53 results on '"S. Arabshahi"'
Search Results
2. Validation of a 24 h recall questionnaire culturally modified for use in rural south Indian populations
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A.K. Subasinghe, A.G. Thrift, R.G. Evans, S. Arabshahi, O. Suresh, K. Kartik, K. Kalyanram, and K.Z. Walker
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Nutrition. Foods and food supply ,TX341-641 ,Biochemistry ,QD415-436 - Published
- 2014
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3. High calcium and iron deficiencies in an elderly rural south Indian population
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A.K. Subasinghe, K.Z. Walker, R.G. Evans, V.K. Srikanth, K. Kartik, K. Kalyanram, S. Arabshahi, O. Suresh, and A.G. Thrift
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Nutrition. Foods and food supply ,TX341-641 ,Biochemistry ,QD415-436 - Published
- 2014
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- View/download PDF
4. Salt and hypertension in rural and urban populations of low to middle income countries: A systematic review and meta-analysis
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A.K. Subasinghe, S. Arabshahi, D. Busingye, R.G. Evans, K.Z. Walker, M.A. Riddell, and A.G. Thrift
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Nutrition. Foods and food supply ,TX341-641 ,Biochemistry ,QD415-436 - Published
- 2014
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5. Unified modeling and experimental realization of electrical and thermal percolation in polymer composites
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Navid Sarikhani, Zohreh S. Arabshahi, Abbas Ali Saberi, and Alireza Z. Moshfegh
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Condensed Matter - Materials Science ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,General Physics and Astronomy ,Physics - Applied Physics ,Applied Physics (physics.app-ph) - Abstract
Correlations between electrical and thermal conduction in polymer composites are blurred due to the complex contribution of charge and heat carriers at the nanoscale junctions of filler particles. Conflicting reports on the lack or existence of thermal percolation in polymer composites have made it the subject of great controversy for decades. Here, we develop a generalized percolation framework that describes both electrical and thermal conductivity within a remarkably wide range of filler-to-matrix conductivity ratios (Y_f/Y_m), covering 20 orders of magnitude. Our unified theory provides a genuine classification of electrical conductivity with typical Y_f/Y_m >= 10^10 as insulator-conductor percolation with the standard power-law behavior, and of thermal conductivity with 10^2, 112 pages (to appear in Applied Physics Reviews)
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- 2022
6. The energy spectrum of X‐rays from rocket‐triggered lightning
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S. Arabshahi, J. R. Dwyer, E. S. Cramer, J. E. Grove, C. Gwon, J. D. Hill, D. M. Jordan, R. J. Lucia, I. B. Vodopiyanov, M. A. Uman, and H. K. Rassoul
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- 2015
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7. Synthesis of MWCNTs Using Monometallic and Bimetallic Combinations of Fe, Co and Ni Catalysts Supported on Nanometric SiC via TCVD
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F. Shahi, M. Akbarzadeh Pasha, A. A. Hosseini, and Z. S. Arabshahi
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Bimetallic catalyst ,Nanometric SiC ,Monometallic catalyst ,lcsh:TP1-1185 ,MWCNTs ,lcsh:Chemical technology ,Wet impregnation ,TCVD - Abstract
Nanometric Carbid Silicon (SiC) supported monometallic and bimetallic catalysts containing Fe, Co, Ni transition metals were prepared by wet impregnation method. Multiwall carbon nanotubes (MWCNTs) were synthesized over the prepared catalysts from catalytic decomposition of acetylene at 850°C by thermal chemical vapor deposition (TCVD) technique. The synthesized nanomaterials (catalysts and CNTs) were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Raman spectroscopy. In this paper, using of nanometric SiC powder as catalyst support was examined and the effect of applied catalyst type on characteristics of grown CNTs was investigated. The results revealed that iron, cobalt and nickel are in oxide, cobalt ferrite (CoFe2O4) and nickel ferrite (NiFe2O4) forms and nanometric SiC powder can be applied as an appropriate catalyst support in CNT growth process. It was observed that the produced CNTs on bimetallic Fe-Co possess smaller average diameter, less amorphous carbon and denser morphology compared to other binary metallic combinations. It was found that the catalytic activity of bimetallic composition decreased in the order of Fe-Co> Fe-Ni> Co-Ni. Furthermore, the monometallic Fe catalyst has the most catalytic activity compared to monometallic Co and Ni catalysts.
- Published
- 2015
8. An analytical approach for calculating energy spectra of relativistic runaway electron avalanches in air
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Ningyu Liu, Hamid K. Rassoul, E. S. Cramer, Igor Vodopiyanov, Joseph R. Dwyer, and S. Arabshahi
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Physics ,Electron avalanche ,Range (particle radiation) ,Geophysics ,Field (physics) ,Space and Planetary Science ,Ionization ,Electric field ,Monte Carlo method ,Electron ,Atomic physics ,Radiation length ,Computational physics - Abstract
Simplified equations describing the transport and energy spectrum of runaway electrons are derived from the basic kinematics of the continuity equations. These equations are useful in modeling the energy distribution of energetic electrons in strong electric fields, such as those found inside thunderstorms. Dwyer and Babich (2011) investigated the generation of low-energy electrons in relativistic runaway electron avalanches. The paper also developed simple analytical expressions to describe the detailed physics of Monte Carlo simulations of relativistic runaway electrons in air. In the current work, the energy spectra of the runaway electron population are studied in detail. Dependence of electron avalanche development on properties such as the avalanche length, radiation length, and the effective Moller scattering efficiency factor are discussed in detail. To describe the shapes of the electron energy spectra for a wide range of electric field strengths, the diffusion term responsible for random deviation of electron energy ionization loss from the mean value is added to the kinetic equation. We find that the diffusion in energy space helps maintain an exponential energy spectrum for electric fields that approach the runaway electron threshold field.
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- 2014
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9. The structure of X-ray emissions from triggered lightning leaders measured by a pinhole-type X-ray camera
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Joseph R. Dwyer, Martin A. Uman, J. W. Matten, Hamid K. Rassoul, A. G. Reid, David M. Smith, Ningyu Liu, M. Schaal, R. J. Lucia, E. S. Cramer, S. Arabshahi, J. D. Hill, and D. M. Jordan
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Physics ,Atmospheric Science ,Dart ,Meteorology ,Monte Carlo method ,Radius ,Astrophysics ,Electron ,Type (model theory) ,Electric charge ,Lightning ,Geophysics ,Space and Planetary Science ,Earth and Planetary Sciences (miscellaneous) ,Pinhole (optics) ,computer ,computer.programming_language - Abstract
We investigate the structure of X-ray emissions from downward triggered lightning leaders using a pinhole-type X-ray camera (XCAM) located at the International Center for Lightning Research and Testing. This study builds on the work of Dwyer et al. (2011), which reported results from XCAM data from the 2010 summer lightning season. Additional details regarding the 2010 data are reported here. During the 2011 summer lightning season, the XCAM recorded 12 out of 17 leaders, 5 of which show downward leader propagation. Of those five leaders, one dart-stepped leader and two chaotic dart leaders are the focus of this paper. These three leaders displayed unique X-ray emission patterns: a chaotic dart leader displayed a diffuse structure (i.e., a wide lateral “spraying” distribution of X-rays), and a dart-stepped leader and a chaotic dart leader exhibited compact emission (i.e., a narrow lateral distribution of strong X-ray emission). These two distinct X-ray emission patterns (compact and diffuse) illustrate the variability of lightning leaders. Using Monte Carlo simulations, we show that the diffuse X-ray source must originate from a diffuse source of energetic electrons or possibly emission from several sources. The compact X-ray sources originate from compact electron sources, and the X-ray source region radius and electric charge contained within the X-ray source region were between 2 and 3 m and on the order of 10–4 C, respectively. For the leaders under investigation, the X-ray source region average currents were determined to be on the order of 102 A.
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- 2014
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10. Numerical simulations of compact intracloud discharges as the Relativistic Runaway Electron Avalanche-Extensive Air Shower process
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Joseph R. Dwyer, S. Arabshahi, Amit K. Nag, Vladimir A. Rakov, and Hamid K. Rassoul
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Physics ,Geophysics ,Air shower ,Relativistic runaway electron avalanche ,Meteorology ,Space and Planetary Science ,Electric field ,Narrow bipolar pulse ,Moment (physics) ,Thunderstorm ,Cosmic ray ,Electron ,Computational physics - Abstract
[1] Compact intracloud discharges (CIDs) are sources of the powerful, often isolated radio pulses emitted by thunderstorms. The VLF-LF radio pulses are called narrow bipolar pulses (NBPs). It is still not clear how CIDs are produced, but two categories of theoretical models that have previously been considered are the Transmission Line (TL) model and the Relativistic Runaway Electron Avalanche-Extensive Air Showers (RREA-EAS) model. In this paper, we perform numerical calculations of RREA-EASs for various electric field configurations inside thunderstorms. The results of these calculations are compared to results from the other models and to the experimental data. Our analysis shows that different theoretical models predict different fundamental characteristics for CIDs. Therefore, many previously published properties of CIDs are highly model dependent. This is because of the fact that measurements of the radiation field usually provide information about the current moment of the source, and different physical models with different discharge currents could have the same current moment. We have also found that although the RREA-EAS model could explain the current moments of CIDs, the required electric fields in the thundercloud are rather large and may not be realistic. Furthermore, the production of NBPs from RREA-EAS requires very energetic primary cosmic ray particles, not observed in nature. If such ultrahigh-energy particles were responsible for NBPs, then they should be far less frequent than is actually observed.
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- 2014
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11. Current Status and the 10 Years Trend in the Malnutrition Indexes of Children under 5 years in Iran
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R Sheikholeslam, M Naghavi, Z Abdollahi, M Zarati, S Vaseghi, F Sadeghi Ghotbabadi, F Kolahdooz, K Samadpour, M Minaei, and S Arabshahi
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Stunting ,RC86-88.9 ,Medical emergencies. Critical care. Intensive care. First aid ,Underweight ,Iran ,Children ,Wasting - Abstract
Background & Objective: Malnutrition is one of the main nutritional problems among children under 5 years especially in developing countries. The effects of malnutrition in this range of age group includes ; disorder of mental and physical growth and development, increase in the morbidity and mortality, decrease of the learning capacity. A detailed epidemiological picture of the prevalent malnutrition status among children under 5 years in different regions of Iran enables health policy makers to identify priorities, establish political commitment and design appropriate interventional programs to prevent and control malnutrition and improve nutritional status of children. To determine the prevalence rate of malnutrition among children under 5 years. Methods: Demographic data, weight and height of 34200 Iranian children between 0-72 months old in 28 provinces of the country in 2005 year based on a cluster sampling were gathered. The subjects' weight and height were measured by trained staff. Prevalence of underweight, stunting, and wasting indicators was determined by measuring the weight and height of subjects in urban and rural areas. EPI6 statistical software, version b6/04, was used for all statistical analyses. Results: 4.7% of the children aged less than five years suffered from stunting (95% CI: 4.5- 4.9%) The prevalence of this type of malnutrition among urban children is significantly less than rural children (95% CI: 3.1- 3.5% and 6.5-7.1% respectively). Meanwhile the prevalence of underweight was 5.2% in the country (95% CI: 5.1-5.4% while the prevalence of this type of malnutrition was significantly less among urban children than those in rural ones. Moreover, the prevalence of wasting was 3.7% (95%CI: 3.5-3.9%) and there was a significant difference in this regard between the urban and rural children. Thus this indicator was significantly higher among urban children than those in rural areas (95%CI: 3.8-4.3% and 3.0-3.5% respectively). Conclusion: The results of the study show that the prevalence of protein-energy malnutrition was low among Iranian children under five years old. In comparison with previous studies, it is felt that there has been a prudent decrease in all malnutrition in all levels. However, there were significant differences in the prevalence of malnutrition in different provinces, which has resulted in the differences in their developmental stages as well. It appears that subjective strategies are required to improve the nutritional and health status among children under five in all provinces.
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- 2008
12. The energy spectrum of X‐rays from rocket‐triggered lightning
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C. Gwon, J. D. Hill, R. J. Lucia, Martin A. Uman, D. M. Jordan, Joseph R. Dwyer, S. Arabshahi, J. E. Grove, Hamid K. Rassoul, E. S. Cramer, and Igor Vodopiyanov
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Physics ,Atmospheric Science ,Photomultiplier ,Scintillation ,Photon ,Spectrometer ,business.industry ,Radiation ,Lightning ,Geophysics ,Optics ,Relativistic runaway electron avalanche ,Space and Planetary Science ,Earth and Planetary Sciences (miscellaneous) ,Atmospheric electricity ,business - Abstract
Although the production of X-rays from natural and rocket-triggered lightning leaders have been studied in detail over the last 10 years, the energy spectrum of the X-rays has never been well measured because the X-rays are emitted in very short but intense bursts that result in pulse pileup in the detectors. The energy spectrum is important because it provides information about the source mechanism for producing the energetic runaway electrons and about the electric fields that they traverse. We have recently developed and operated the first spectrometer for the energetic radiation from lightning. The instrument is part of the Atmospheric Radiation Imagery and Spectroscopy (ARIS) project and will be referred to as ARIS-S (ARIS Spectrometer). It consists of seven 3′′ NaI(Tl)/photomultiplier tube scintillation detectors with different thicknesses of attenuators, ranging from no attenuator to more than 1′′ of lead placed over the detector (all the detectors are in a 1/8′′ thick aluminum box). Using X-ray pulses preceding 48 return strokes in 8 rocket-triggered lightnings, we found that the spectrum of X-rays from leaders is too soft to be consistent with Relativistic Runaway Electron Avalanche. It has a power law dependence on the energies of the photons, and the power index, λ, is between 2.5 and 3.5. We present the details of the design of the instrument and the results of the analysis of the lightning data acquired during the summer of 2012.
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- 2015
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13. Observation of a gamma-ray flash at ground level in association with a cloud-to-ground lightning return stroke
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E. S. Cramer, Ningyu Liu, M. Schaal, Hamid K. Rassoul, Joseph R. Dwyer, S. Arabshahi, Douglas M. Jordan, Martin A. Uman, and J. D. Hill
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Physics ,Atmospheric Science ,Ecology ,Meteorology ,Gamma ray ,Paleontology ,Soil Science ,Upper-atmospheric lightning ,Forestry ,Astrophysics ,Aquatic Science ,Oceanography ,Solar physics ,Lightning ,Flash (photography) ,Geophysics ,Relativistic runaway electron avalanche ,Space and Planetary Science ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Thunderstorm ,Earth-Surface Processes ,Water Science and Technology ,Terrestrial gamma-ray flash - Abstract
[1] Terrestrial gamma-ray flashes (TGFs) are bright, sub-millisecond bursts of gamma-rays, originating within the Earth's atmosphere. Most TGFs have been detected by spacecraft in low-Earth orbit. Only two TGFs have previously been observed from within our atmosphere: one at ground level and one from an aircraft at 14.1 km. We report on a new TGF-like gamma-ray flash observed at ground level, detected by the 19-station Thunderstorm Energetic Radiation Array (TERA) at the University of Florida/Florida Tech International Center for Lightning Research and Testing (ICLRT). The gamma-ray flash, which had a duration of 52.7 μs, occurred on June 30, 2009 during a natural negative cloud-to-ground lightning return stroke, 191 μs after the start of the stroke. This event is the first definitive association of a gamma-ray flash with natural CG lightning and is among the most direct links to a specific lightning process so far. For this event, 19 gamma-rays were recorded, with the highest energy exceeding 20 MeV. The high-energy radiation exhibited very different behavior from the typical x-ray emission from lightning. Specifically, the gamma-ray flash had a much harder energy spectrum, consistent with relativistic runaway electron avalanche (RREA) multiplication; it did not arrive in sub-microsecond bursts, typical of leader emission from lightning, and it occurred well after the start of the return stroke, which has not been previously observed for the x-ray emission from lightning. Nevertheless, we present evidence that the source region for the gamma ray flash was the same as that for the preceding leader x-ray bursts.
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- 2012
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14. Electric field of a relativistic electron avalanche
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Thomas C. Marshall, Vernon Cooray, Joseph R. Dwyer, Gerald Cooray, and S. Arabshahi
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Electromagnetic field ,Physics ,Physics::Instrumentation and Detectors ,business.industry ,Electron ,Radiation ,Avalanche breakdown ,Transverse mode ,Computational physics ,Electron avalanche ,Impact ionization ,Nonlinear Sciences::Adaptation and Self-Organizing Systems ,Optics ,Electric field ,business - Abstract
In the present study, electromagnetic fields of accelerating charges were utilized to evaluate the electromagnetic fields generated by a relativistic electron avalanche. In the analysis it is assumed that all the electrons in the avalanche are moving with the same speed. In other words, the growth or the decay of the number of electrons takes place only at the head of the avalanche. It is shown that the radiation is emanating only from the head of the avalanche where electrons are being accelerated. It is also shown that an analytical expression for the radiation field of the avalanche at any distance can be written directly in terms of the e-folding length of the avalanche. This makes it possible to extract directly the spatial variation of the e-folding length of the avalanche from the measured radiation fields.
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- 2012
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15. Steps towards CAD-FEA integration
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David C. Barton, S. Arabshahi, and N. K. Shaw
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Scheme (programming language) ,Structure (mathematical logic) ,Engineering drawing ,Computer science ,Process (engineering) ,General Engineering ,CAD ,computer.software_genre ,Finite element method ,Computer Science Applications ,Transformation (function) ,Modeling and Simulation ,Computer Aided Design ,computer ,Software ,Abstraction (linguistics) ,computer.programming_language - Abstract
Using current Computer Aided Design (CAD) and Finite Element Analysis (FEA) pre-processing systems, a large proportion of the analyst's time is spent preparing an idealised model of a part or structure for analysis. Although complete geometric information for the part is often available in the form of a solid model, this is seldom taken advantage of because of the amount of time required to simplify and idealise the geometry for the subsequent meshing stage. In fact, analysts often find it easier to reconstruct the idealised model from scratch, a process which is error prone and prohibits linking the analysis results to the product in a formal way. This paper gives an overview of a future system which would allow and encourage more automated CAD-FEA transformation using tools that operate directly on the solid model. Functional components for such a system are discussed together with issues that should be addressed in order to achieve a fully integrated CAD-FEA transformtion scheme. The overall aim is to make the transition from a solid model to an idealised model suitable for analysis an easier, more robust and less time-consuming task.
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- 1993
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16. Simulating the impact of kraft pulping and bleaching parameters on Eucalyptus camaldulensis pulp properties using MATLAB
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Raimo O. Malinen, Pedram Fatehi, Yonghao Ni, Zainab Ziaee, and S. Arabshahi
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Chlorine dioxide ,General Chemical Engineering ,Pulp (paper) ,Hexenuronic acid ,Mineralogy ,engineering.material ,Pulp and paper industry ,Kappa number ,HEXA ,chemistry.chemical_compound ,Eucalyptus camaldulensis ,chemistry ,Kraft process ,engineering ,Chemical pulp - Abstract
In this work, Eucalyptus camaldulensis was evaluated as the raw material for chemical pulp under different pulping and bleaching conditions. The pulping was carried out at different H-factors, and at different effective alkalis. The resulting pulps were then oxygen delignified and bleached using various dosages of bleaching chemicals in a D0EpD1 sequence. The effect of independent variables (pulping or bleaching variables) on dependent variables (pulp properties) was analysed based on the multivariable least square method via MATLAB software. An agreement was found between the results predicted from the models and the experimental data. To obtain a kappa number of 15, the optimum pulping conditions were a temperature of 155°C, a time of 225 min, and an EA of 23%. Also, the hexenuronic acid (HexA) content of cooked pulp was significantly decreased in the chlorine dioxide bleaching stages, and was only marginally related to the final HexA content of bleached pulps. Dans ce travail, on evalue l'Eucalyptus camaldulensis comme matiere premiere pour produire de la pulpe chimique dans differentes conditions de desintegration et de blanchiment. La desintegration a ete effectuee a differents facteurs H et avec differents materiaux alcalins. Les pulpes resultantes etaient ensuite delignifiees a l'oxygene et blanchies avec differents dosages d'agents chimiques de blanchiment dans une sequence D0EpD1. On a analyse l'effet des variables independantes (variables de desintegration ou de blanchiment) sur les variables dependantes (proprietes des pulpes) en se basant sur la methode multivariable des moindres carres via un logiciel MATLAB. On a obtenu une bonne correspondance entre les resultats predits par les modeles et les donnees experimentales. Pour obtenir un nombre kappa de 15, les conditions optimales de desintegration etaient : temperature de 155°C, duree de 225 min et une valeur de EA de 23%. De plus, le contenu d'acide hexenuronique (HexA) de la pulpe etait significativement reduit durant les etapes de blanchiment au dioxyde de chlore et n'etait que marginalement lie au contenu final de HexA des pulpes blanchies.
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- 2010
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17. Towards integrated design and analysis
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David C. Barton, S. Arabshahi, and N. K. Shaw
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Functional specification ,Engineering drawing ,Integrated design ,Engineering ,business.industry ,Applied Mathematics ,General Engineering ,computer.software_genre ,Computer Graphics and Computer-Aided Design ,Automation ,Finite element method ,Software ,Systems analysis ,Computer Aided Design ,business ,computer ,Requirements analysis ,Analysis - Abstract
A systems analysis technique is used to investigate and better understand the processes involved in finite element modelling. Two different starting points are considered: engineering drawings and solid models. The breakdown of activities involved in finite element analysis from a solid model is used as a requirements definition and functional specification for software tools to facilitate automation of finite modelling and eventual integration of design and analysis.
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- 1991
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18. Functional Connectivity Changes on Resting-State fMRI after Mild Traumatic Brain Injury: A Systematic Review.
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Dogra S, Arabshahi S, Wei J, Saidenberg L, Kang SK, Chung S, Laine A, and Lui YW
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- Humans, Brain diagnostic imaging, Brain physiopathology, Rest, Nerve Net diagnostic imaging, Nerve Net physiopathology, Brain Mapping methods, Connectome methods, Magnetic Resonance Imaging methods, Brain Concussion diagnostic imaging, Brain Concussion physiopathology
- Abstract
Background: Mild traumatic brain injury is theorized to cause widespread functional changes to the brain. Resting-state fMRI may be able to measure functional connectivity changes after traumatic brain injury, but resting-state fMRI studies are heterogeneous, using numerous techniques to study ROIs across various resting-state networks., Purpose: We systematically reviewed the literature to ascertain whether adult patients who have experienced mild traumatic brain injury show consistent functional connectivity changes on resting-state -fMRI, compared with healthy patients., Data Sources: We used 5 databases (PubMed, EMBASE, Cochrane Central, Scopus, Web of Science)., Study Selection: Five databases (PubMed, EMBASE, Cochrane Central, Scopus, and Web of Science) were searched for research published since 2010. Search strategies used keywords of "functional MR imaging" and "mild traumatic brain injury" as well as related terms. All results were screened at the abstract and title levels by 4 reviewers according to predefined inclusion and exclusion criteria. For full-text inclusion, each study was evaluated independently by 2 reviewers, with discordant screening settled by consensus., Data Analysis: Data regarding article characteristics, cohort demographics, fMRI scan parameters, data analysis processing software, atlas used, data characteristics, and statistical analysis information were extracted., Data Synthesis: Across 66 studies, 80 areas were analyzed 239 times for at least 1 time point, most commonly using independent component analysis. The most analyzed areas and networks were the whole brain, the default mode network, and the salience network. Reported functional connectivity changes varied, though there may be a slight trend toward decreased whole-brain functional connectivity within 1 month of traumatic brain injury and there may be differences based on the time since injury., Limitations: Studies of military, sports-related traumatic brain injury, and pediatric patients were excluded. Due to the high number of relevant studies and data heterogeneity, we could not be as granular in the analysis as we would have liked., Conclusions: Reported functional connectivity changes varied, even within the same region and network, at least partially reflecting differences in technical parameters, preprocessing software, and analysis methods as well as probable differences in individual injury. There is a need for novel rs-fMRI techniques that better capture subject-specific functional connectivity changes., (© 2024 by American Journal of Neuroradiology.)
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- 2024
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19. A Comprehensive and Broad Approach to Resting-State Functional Connectivity in Adult Patients with Mild Traumatic Brain Injury.
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Arabshahi S, Chung S, Alivar A, Amorapanth PX, Flanagan SR, Foo FA, Laine AF, and Lui YW
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- Humans, Male, Female, Adult, Middle Aged, Brain Concussion diagnostic imaging, Brain Concussion physiopathology, Rest, Young Adult, Connectome methods, Brain diagnostic imaging, Brain physiopathology, Brain Mapping methods, Nerve Net diagnostic imaging, Nerve Net physiopathology, Magnetic Resonance Imaging methods
- Abstract
Background and Purpose: Several recent works using resting-state fMRI suggest possible alterations of resting-state functional connectivity after mild traumatic brain injury. However, the literature is plagued by various analysis approaches and small study cohorts, resulting in an inconsistent array of reported findings. In this study, we aimed to investigate differences in whole-brain resting-state functional connectivity between adult patients with mild traumatic brain injury within 1 month of injury and healthy control subjects using several comprehensive resting-state functional connectivity measurement methods and analyses., Materials and Methods: A total of 123 subjects (72 patients with mild traumatic brain injury and 51 healthy controls) were included. A standard fMRI preprocessing pipeline was used. ROI/seed-based analyses were conducted using 4 standard brain parcellation methods, and the independent component analysis method was applied to measure resting-state functional connectivity. The fractional amplitude of low-frequency fluctuations was also measured. Group comparisons were performed on all measurements with appropriate whole-brain multilevel statistical analysis and correction., Results: There were no significant differences in age, sex, education, and hand preference between groups as well as no significant correlation between all measurements and these potential confounders. We found that each resting-state functional connectivity measurement revealed various regions or connections that were different between groups. However, after we corrected for multiple comparisons, the results showed no statistically significant differences between groups in terms of resting-state functional connectivity across methods and analyses., Conclusions: Although previous studies point to multiple regions and networks as possible mild traumatic brain injury biomarkers, this study shows that the effect of mild injury on brain resting-state functional connectivity has not survived after rigorous statistical correction. A further study using subject-level connectivity analyses may be necessary due to both subtle and variable effects of mild traumatic brain injury on brain functional connectivity across individuals., (© 2024 by American Journal of Neuroradiology.)
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- 2024
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20. Risk factors for incident cardiovascular events and their population attributable fractions in rural India: The Rishi Valley Prospective Cohort Study.
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Birhanu MM, Zengin A, Joshi R, Evans RG, Kalyanram K, Kartik K, Riddell MA, Suresh O, Srikanth VK, Arabshahi S, Thomas N, and Thrift AG
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- Humans, India epidemiology, Female, Male, Middle Aged, Prospective Studies, Adult, Incidence, Risk Factors, Proportional Hazards Models, Diabetes Mellitus epidemiology, Obesity, Abdominal epidemiology, Obesity, Abdominal complications, Cardiovascular Diseases epidemiology, Cardiovascular Diseases etiology, Hypertension epidemiology, Rural Population statistics & numerical data
- Abstract
Objective: We prospectively determined incident cardiovascular events and their association with risk factors in rural India., Methods: We followed up with 7935 adults from the Rishi Valley Prospective Cohort Study to identify incident cardiovascular events. Using Cox proportional hazards regression, we estimated hazard ratios (HRs) with 95% confidence intervals (95% CI) for associations between potential risk factors and cardiovascular events. Population attributable fractions (PAFs) for risk factors were estimated using R ('averisk' package)., Results: Of the 4809 participants without prior cardiovascular disease, 57.7% were women and baseline mean age was 45.3 years. At follow-up (median of 4.9 years, 23,180 person-years [PYs]), 202 participants developed cardiovascular events, equating to an incidence of 8.7 cardiovascular events/1000 PYs. Incidence was greater in those with hypertension (hazard ratio [HR] [95% CI] 1.73 [1.21-2.49], adjusted PAF 18%), diabetes (1.96 [1.15-3.36], 4%) or central obesity (1.77 [1.23, 2.54], 9%) which together accounted for 31% of the PAF. Non-traditional risk factors such as night sleeping hours and number of children accounted for 16% of the PAF., Conclusions: Both traditional and non-traditional cardiovascular risk factors are important contributors to incident cardiovascular events in rural India. Interventions targeted to these factors could assist in reducing the incidence of cardiovascular events., (© 2024 The Authors Tropical Medicine & International Health Published by John Wiley & Sons Ltd.)
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- 2024
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21. Comparison of the performance of cardiovascular risk prediction tools in rural India: the Rishi Valley Prospective Cohort Study.
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Birhanu MM, Zengin A, Evans RG, Joshi R, Kalyanram K, Kartik K, Danaei G, Barr E, Riddell MA, Suresh O, Srikanth VK, Arabshahi S, Thomas N, and Thrift AG
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- Male, Humans, Risk Factors, Prospective Studies, Australia, Risk Assessment methods, Heart Disease Risk Factors, Cardiovascular Diseases diagnosis, Hypertension
- Abstract
Aims: We compared the performance of cardiovascular risk prediction tools in rural India., Methods and Results: We applied the World Health Organization Risk Score (WHO-RS) tools, Australian Risk Score (ARS), and Global risk (Globorisk) prediction tools to participants aged 40-74 years, without prior cardiovascular disease, in the Rishi Valley Prospective Cohort Study, Andhra Pradesh, India. Cardiovascular events during the 5-year follow-up period were identified by verbal autopsy (fatal events) or self-report (non-fatal events). The predictive performance of each tool was assessed by discrimination and calibration. Sensitivity and specificity of each tool for identifying high-risk individuals were assessed using a risk score cut-off of 10% alone or this 10% cut-off plus clinical risk criteria of diabetes in those aged >60 years, high blood pressure, or high cholesterol. Among 2333 participants (10 731 person-years of follow-up), 102 participants developed a cardiovascular event. The 5-year observed risk was 4.4% (95% confidence interval: 3.6-5.3). The WHO-RS tools underestimated cardiovascular risk but the ARS overestimated risk, particularly in men. Both the laboratory-based (C-statistic: 0.68 and χ2: 26.5, P = 0.003) and non-laboratory-based (C-statistic: 0.69 and χ2: 20.29, P = 0.003) Globorisk tools showed relatively good discrimination and agreement. Addition of clinical criteria to a 10% risk score cut-off improved the diagnostic accuracy of all tools., Conclusion: Cardiovascular risk prediction tools performed disparately in a setting of disadvantage in rural India, with the Globorisk performing best. Addition of clinical criteria to a 10% risk score cut-off aids assessment of risk of a cardiovascular event in rural India., Lay Summary: In a cohort of people without prior cardiovascular disease, tools used to predict the risk of cardiovascular events varied widely in their ability to accurately predict who would develop a cardiovascular event.The Globorisk, and to a lesser extent the ARS, tools could be appropriate for this setting in rural India.Adding clinical criteria, such as sustained high blood pressure, to a cut-off of 10% risk of a cardiovascular event within 5 years could improve identification of individuals who should be monitored closely and provided with appropriate preventive medications., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)
- Published
- 2024
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22. Improving across-dataset brain tissue segmentation for MRI imaging using transformer.
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Rao VM, Wan Z, Arabshahi S, Ma DJ, Lee PY, Tian Y, Zhang X, Laine AF, and Guo J
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Brain tissue segmentation has demonstrated great utility in quantifying MRI data by serving as a precursor to further post-processing analysis. However, manual segmentation is highly labor-intensive, and automated approaches, including convolutional neural networks (CNNs), have struggled to generalize well due to properties inherent to MRI acquisition, leaving a great need for an effective segmentation tool. This study introduces a novel CNN-Transformer hybrid architecture designed to improve brain tissue segmentation by taking advantage of the increased performance and generality conferred by Transformers for 3D medical image segmentation tasks. We first demonstrate the superior performance of our model on various T1w MRI datasets. Then, we rigorously validate our model's generality applied across four multi-site T1w MRI datasets, covering different vendors, field strengths, scan parameters, and neuropsychiatric conditions. Finally, we highlight the reliability of our model on test-retest scans taken in different time points. In all situations, our model achieved the greatest generality and reliability compared to the benchmarks. As such, our method is inherently robust and can serve as a valuable tool for brain related T1w MRI studies. The code for the TABS network is available at: https://github.com/raovish6/TABS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Rao, Wan, Arabshahi, Ma, Lee, Tian, Zhang, Laine and Guo.)
- Published
- 2022
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23. Association of hypertension with infection and inflammation in a setting of disadvantage in rural India.
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Busingye D, Evans RG, Arabshahi S, Riddell MA, Srikanth VK, Kartik K, Kalyanram K, Zhu X, Suresh O, and Thrift AG
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- Male, Female, Humans, Case-Control Studies, Rural Population, Inflammation diagnosis, Inflammation epidemiology, India epidemiology, Biomarkers, Homocysteine, C-Reactive Protein metabolism, Hypertension diagnosis, Hypertension epidemiology, Hypertension complications
- Abstract
We assessed the association of hypertension with markers of inflammation and infection in a rural and disadvantaged Indian population. In a case-control study, we age- and gender-matched 300 cases with hypertension to 300 controls without hypertension. Blood pressure was measured according to a strict protocol. We measured markers of inflammation and infection including serum high-sensitivity C-reactive protein (hs-CRP), blood lymphocyte count, serum homocysteine, tooth loss, overcrowding and exposure to fecal contamination. Multivariable conditional logistic regression was used to determine their association with hypertension. Median serum hs-CRP was 42% greater in cases than controls, while median serum homocysteine was 10% greater. In multivariable conditional logistic regression, elevated homocysteine (OR 1.75, 95% CI 1.09-2.82), greater lymphocyte count (OR 1.49, 95% CI 1.01-2.01) and exposure to fecal contamination, defined as a distance from the field used for toilet purposes to the household of ≤50 m (OR 2.38, 95% CI 1.07-5.29), were independently associated with hypertension in this rural population. In separate analyses for each gender, elevated hs-CRP (OR 2.62, 95% CI 1.04-6.58) was associated with hypertension in men, whereas edentulism (OR 4.75, 95% CI 1.62-13.96) was associated with greater odds of hypertension in women. Our findings demonstrate specific associations between hypertension and markers of inflammation and infection including hs-CRP, homocysteine, lymphocyte count, edentulism and exposure to fecal contamination. Thus, strategies aimed at reducing inflammation and infection may reduce the burden of hypertension in such settings of disadvantage in rural India., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)
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- 2022
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24. Renal and dietary factors associated with hypertension in a setting of disadvantage in rural India.
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Evans RG, Subasinghe AK, Busingye D, Srikanth VK, Kartik K, Kalyanram K, Suresh O, Arabshahi S, Curkpatrick I, O'Dea K, Walker KZ, Kaye M, Yang J, Thomas N, Arulappan G, and Thrift AG
- Subjects
- Adult, Blood Pressure, Humans, India epidemiology, Sodium, Hypertension epidemiology, Rural Population
- Abstract
Using a case-control design, we determined risk factors associated with hypertension in a disadvantaged rural population in southern India. Three hundred adults with hypertension and 300 age- and sex-matched controls were extensively phenotyped. Underweight (29%, body mass index < 18.0 kg m
-2 ), chronic kidney disease (25%, estimated glomerular filtration rate <60 ml min-1 1.73 m-2 ) and anemia (82%) were highly prevalent. The ratio of sodium to potassium excretion was high (8.2). In multivariable conditional logistic regression of continuous variables dichotomized by their median value, hypertension was independently associated with greater abdominal adiposity as assessed by waist-hip ratio [odds ratio (95% confidence interval), 1.89 (1.21-2.97)], lesser protein intake as assessed by 24 h urea excretion [0.39 (0.24-0.65)], and lesser plasma renin activity [0.54 (0.35-0.84)]. Hypertension tended to be independently associated with lesser serum potassium concentration [0.66 (0.44-1.01), P = 0.06]. Furthermore, those with hypertension reported less frequent intake of vegetables and urinary sodium-potassium ratio correlated positively with serum sodium-potassium ratio (r = 0.18). Hypertension was also independently associated with lesser blood hemoglobin concentration [0.48 (0.26-0.88)]. Blood hemoglobin concentration was positively associated with serum iron (r = 0.41) and ferritin (r = 0.25) concentration and negatively associated with total iron binding capacity (r = -0.17), reflecting iron-deficiency anemia. Our findings indicate potential roles for deficient intake of potassium and protein, and iron-deficiency anemia, in the pathophysiology of hypertension in a setting of disadvantage in rural India. Imbalanced intake of potassium and sodium may be driven partly by deficient intake of vegetables or fruit., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited part of Springer Nature.)- Published
- 2021
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25. ASHA-Led Community-Based Groups to Support Control of Hypertension in Rural India Are Feasible and Potentially Scalable.
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Riddell MA, Mini GK, Joshi R, Thrift AG, Guggilla RK, Evans RG, Thankappan KR, Chalmers K, Chow CK, Mahal AS, Kalyanram K, Kartik K, Suresh O, Thomas N, Maulik PK, Srikanth VK, Arabshahi S, Varma RP, D'Esposito F, and Oldenburg B
- Abstract
Background: To improve the control of hypertension in low- and middle-income countries, we trialed a community-based group program co-designed with local policy makers to fit within the framework of India's health system. Trained accredited social health activists (ASHAs), delivered the program, in three economically and developmentally diverse settings in rural India. We evaluated the program's implementation and scalability. Methods: Our mixed methods process evaluation was guided by the United Kingdom Medical Research Council guidelines for complex interventions. Meeting attendance reports, as well as blood pressure and weight measures of attendees and adherence to meeting content and use of meeting tools were used to evaluate the implementation process. Thematic analysis of separate focus group discussions with participants and ASHAs as well as meeting reports and participant evaluation were used to investigate the mechanisms of impact. Results: Fifteen ASHAs led 32 community-based groups in three rural settings in the states of Kerala and Andhra Pradesh, Southern India. Overall, the fidelity of intervention delivery was high. Six meetings were delivered over a 3-month period to each of the intervention groups. The mean number of meetings attended by participants at each site varied significantly, with participants in Rishi Valley attending fewer meetings [mean (SD) = 2.83 (1.68)] than participants in West Godavari (Tukeys test, p = 0.009) and Trivandrum (Tukeys test, p < 0.001) and participants in West Godavari [mean (SD) = 3.48 (1.72)] attending significantly fewer meetings than participants in Trivandrum [mean (SD) = 4.29 (1.76), Tukeys test, p < 0.001]. Culturally appropriate intervention resources and the training of ASHAs, and supportive supervision of them during the program were critical enablers to program implementation. Although highly motivated during the implementation of the program ASHA reported historical issues with timely remuneration and lack of supportive supervision. Conclusions: Culturally appropriate community-based group programs run by trained and supported ASHAs are a successful and potentially scalable model for improving the control of hypertension in rural India. However, consideration of issues related to unreliable/insufficient remuneration for ASHAs, supportive supervision and their formal role in the wider health workforce in India will be important to address in future program scale up. Trial Registration: Clinical Trial Registry of India [CTRI/2016/02/006678, Registered prospectively]., Competing Interests: RG is a shareholder in several global medical and bio-pharmaceutical companies as part of his investment portfolio. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Riddell, Mini, Joshi, Thrift, Guggilla, Evans, Thankappan, Chalmers, Chow, Mahal, Kalyanram, Kartik, Suresh, Thomas, Maulik, Srikanth, Arabshahi, Varma, D'Esposito and Oldenburg.)
- Published
- 2021
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26. Brain Amyloid Burden and Resting-State Functional Connectivity in Late Middle-Aged Hispanics.
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Tahmi M, Rippon B, Palta P, Soto L, Ceballos F, Pardo M, Sherwood G, Hernandez G, Arevalo R, He H, Sedaghat A, Arabshahi S, Teresi J, Moreno H, Brickman AM, Razlighi QR, and Luchsinger JA
- Abstract
Non-linear relations of brain amyloid beta (Aβ) with task- based functional connectivity (tbFC) measured with functional magnetic resonance imaging (fMRI) have been reported in late middle age. Our objective was to examine the association between brain Aβ and resting-state functional connectivity (rsFC) in late middle-aged adults. Global brain Aβ burden was ascertained with
18 F-Florbetaben Positron Emission Tomography (PET); rsFC was ascertained on 3T Magnetic Resonance Imaging (MRI) among 333 late middle-aged Hispanics adults without dementia in four major brain functional connectivity networks: default mode network (DMN), fronto-parietal control network (FPC), salience network (SAL) and dorsal attention network (DAN). We examined the relationship of global brain Aβ with rsFC using multivariable linear regression adjusted for age, sex, education, and APOE-ε4 genotype. We quantified the non-linear associations both with quadratic terms and by categorizing Aβ into three groups: low Aβ, intermediate Aβ, and positive Aβ. We found no significant linear or non-linear associations between Aβ, measured either continuously or categorically, with rsFC in the examined networks. Our null findings may be explained by the younger age of our participants in whom amyloid burden is relatively low. It is also possible that the recently reported non-linear relationship is exclusive to task fMRI and not rsfMRI., (Copyright © 2020 Tahmi, Rippon, Palta, Soto, Ceballos, Pardo, Sherwood, Hernandez, Arevalo, He, Sedaghat, Arabshahi, Teresi, Moreno, Brickman, Razlighi and Luchsinger.)- Published
- 2020
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27. Molecular characterization of Shigella species isolated from diarrheal patients in Tehran, Iran: phylogenetic typing and its association with virulence gene profiles and a novel description of Shigella invasion associated locus.
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Arabshahi S, Novinrooz A, Ranjbar R, and Imani Fooladi AA
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- Diarrhea microbiology, Dysentery, Bacillary microbiology, Humans, Iran epidemiology, Multiplex Polymerase Chain Reaction, Phylogeny, Shigella genetics, Shigella pathogenicity, Virulence Factors genetics, Dysentery, Bacillary epidemiology, Shigella isolation & purification
- Abstract
The present study aims to employ a multiplex PCR-based method for phylogenetic typing of Shigella and determine the frequency of several virulence genes among Shigella phylogenetic clades and species. Species identification, phylogenetic typing of 44 previously diagnosed Shigella isolates, and frequency of virulence genes and loci, virA, virB, virF, ipaBCD, ial, sen, and set1A were investigated through performing several PCR assays. Distribution of virulence genes among Shigella phylogenetic clades and species was determined by the statistical analysis. The identities of 40 isolates out of 44 were confirmed as Shigella, and these isolates were classified in four phylogenetic clades, S1 (7.5%), S2 (52.5%), S3 (20%), and S5 (20%) and 4 species, S. sonnei (52.5%), S. flexneri (22.5%), S. dysenteriae (20%), and S. boydii (5%). The prevalence of virA, virB, virF, ipaBCD, ial, sen, and set1A was determined as 67.5%, 72.5%, 72.5%, 65%, 75%, 40%, and 5%, respectively. The presence of sen, uidA, or set1A was found to be statistically correlated with either of Shigella phylogenetic clades or species. A significant statistically association was also determined between set1A and Shigella phylogenetic clades. Furthermore, the nucleotide sequence of invasion-associated locus (ial) was determined and mapped on Shigella genome through in silico analysis. The current study shows the distribution of Shigella isolates and its key virulence genes within the five recently described phylogenetic clades for the first time in the Asia. This is also the first description of ial nucleotide sequence and its exact location on Shigella genome after its initial identification.
- Published
- 2020
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28. Effectiveness of a scalable group-based education and monitoring program, delivered by health workers, to improve control of hypertension in rural India: A cluster randomised controlled trial.
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Gamage DG, Riddell MA, Joshi R, Thankappan KR, Chow CK, Oldenburg B, Evans RG, Mahal AS, Kalyanram K, Kartik K, Suresh O, Thomas N, Mini GK, Maulik PK, Srikanth VK, Arabshahi S, Varma RP, Guggilla RK, D'Esposito F, Sathish T, Alim M, and Thrift AG
- Subjects
- Adolescent, Adult, Aged, Blood Pressure physiology, Blood Pressure Determination methods, Cluster Analysis, Female, Follow-Up Studies, Humans, Hypertension diagnosis, India epidemiology, Male, Middle Aged, Surveys and Questionnaires, Treatment Outcome, Young Adult, Community Health Workers, Delivery of Health Care methods, Hypertension epidemiology, Hypertension therapy, Patient Education as Topic methods, Rural Population
- Abstract
Background: New methods are required to manage hypertension in resource-poor settings. We hypothesised that a community health worker (CHW)-led group-based education and monitoring intervention would improve control of blood pressure (BP)., Methods and Findings: We conducted a baseline community-based survey followed by a cluster randomised controlled trial of people with hypertension in 3 rural regions of South India, each at differing stages of epidemiological transition. Participants with hypertension, defined as BP ≥ 140/90 mm Hg or taking antihypertensive medication, were advised to visit a doctor. In each region, villages were randomly assigned to intervention or usual care (UC) in a 1:2 ratio. In intervention clusters, trained CHWs delivered a group-based intervention to people with hypertension. The program, conducted fortnightly for 3 months, included monitoring of BP, education about hypertension, and support for healthy lifestyle change. Outcomes were assessed approximately 2 months after completion of the intervention. The primary outcome was control of BP (BP < 140/90 mm Hg), analysed using mixed effects regression, clustered by village within region and adjusted for baseline control of hypertension (using intention-to-treat principles). Of 2,382 potentially eligible people, 637 from 5 intervention clusters and 1,097 from 10 UC clusters were recruited between November 2015 and April 2016, with follow-up occurring in 459 in the intervention group and 1,012 in UC. Mean age was 56.9 years (SD 13.7). Baseline BP was similar between groups. Control of BP improved from baseline to follow-up more in the intervention group (from 227 [49.5%] to 320 [69.7%] individuals) than in the UC group (from 528 [52.2%] to 624 [61.7%] individuals) (odds ratio [OR] 1.6, 95% CI 1.2-2.1; P = 0.001). In secondary outcome analyses, there was a greater decline in systolic BP in the intervention than UC group (-5.0 mm Hg, 95% CI -7.1 to -3.0; P < 0.001) and a greater decline in diastolic BP (-2.1 mm Hg, 95% CI -3.6 to -0.6; P < 0.006), but no detectable difference in the use of BP-lowering medications between groups (OR 1.2, 95% CI 0.8-1.9; P = 0.34). Similar results were found when using imputation analyses that included those lost to follow-up. Limitations include a relatively short follow-up period and use of outcome assessors who were not blinded to the group allocation., Conclusions: While the durability of the effect is uncertain, this trial provides evidence that a low-cost program using CHWs to deliver an education and monitoring intervention is effective in controlling BP and is potentially scalable in resource-poor settings globally., Trial Registration: The trial was registered with the Clinical Trials Registry-India (CTRI/2016/02/006678)., Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: CKC reports grants from the National Health and Medical Research Council (NHMRC) and National Heart Foundation, outside the submitted work; RGE reports grants from the NHMRC, during the conduct of the study. KKal, KKar and AGT report grants from NHMRC for this study and for other projects outside the submitted work; RKG reports a grant from the European Commission and the Ministry of Science and Higher Education, Republic of Poland under the H2020-MSCA-COFUND-2016-DP Grant (Grant Agreement No. 754432). RKG reports being a stock holder in three Indian multinational pharmaceutical (Ajanta Pharma Limited, Divi’s Laboratories Limited, and NATCO Pharma Limited); no other relationships or activities that could appear to have influenced the submitted work exist.
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- 2020
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29. In-silico design and production of a novel antigenic chimeric Shigella IpaB fused to C-terminal of Clostridium perfringens enterotoxin.
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Arabshahi S, Derakhshandeh A, Nayeri Fasaei B, and Novinrooz A
- Subjects
- Animals, Antigens, Bacterial immunology, Bacterial Proteins chemistry, Bacterial Proteins immunology, Enterotoxins chemistry, Enterotoxins immunology, Epitopes genetics, Epitopes immunology, Female, Humans, Mass Spectrometry, Mice, Models, Molecular, Protein Conformation, Protein Domains genetics, Recombinant Fusion Proteins immunology, Structure-Activity Relationship, Antigens, Bacterial genetics, Bacterial Proteins genetics, Computational Biology methods, Enterotoxins genetics, Protein Engineering, Recombinant Fusion Proteins genetics
- Abstract
The emergence of antibiotic-resistant phenotypes in Shigella serotypes and the high mortality rate, approximately one million dead annually, in affected patients announce a global demand for an effective serotype-independent vaccine against Shigella. This study aims to design, express, and purify a novel chimeric protein, as a serotype-independent vaccine candidate against Shigella containing full-length Shigella invasion plasmid antigen B (IpaB) and a C-terminal fragment (residues 194-319) of Clostridium perfringens enterotoxin (C-CPE) as a mucosal adjuvant. Several online databases and bioinformatics software were utilized to design the chimeric protein and the relative recombinant gene. The recombinant gene encoding IpaB-CPE
194-319 was synthesized, cloned into pACYCDuet-1 expression vector, and transferred to E. coli Bl21 (DE3) cells. IpaB-CPE194-319 was then expressed in auto-induction medium, purified and characterized using MALDI-TOF-TOF mass spectrometry. Followed by subcutaneous injection of the purified IpaB-CPE194-319 to BALB/c mice, antigenicity of this chimeric protein was determined through performing dot-blot immunoassay on nitrocellulose membrane using mice sera. The outcomes of this study show the successful design, efficient expression, and purification of IpaB-CPE194-319 divalent chimeric protein under mentioned conditions. The obtained results also demonstrate the intrinsic antigenic property of IpaB-CPE194-319 .- Published
- 2019
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30. Knowledge of risk factors for hypertension in a rural Indian population.
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Busingye D, Arabshahi S, Evans RG, Riddell MA, Srikanth VK, Kartik K, Kalyanram K, Zhu X, Suresh O, Howard G, and Thrift AG
- Abstract
Objective: To study knowledge of risk factors and consequences of hypertension in a rural population in South India., Methods: This is a community-based study conducted among adults of a rural population in the Rishi Valley, India. Residents of randomised rural villages were invited to participate in a study of hypertension. We obtained measures of blood pressure, height, weight, waist and hip circumferences and questionnaire-based information on knowledge about hypertension, sociodemographic characteristics and health behaviours. Multivariable logistic regression analyses were conducted to determine the factors associated with knowledge of risk factors for hypertension (knowledge of ≥2 risk factors)., Results: The study comprised 641 adults; 132 aware and 218 unaware of their hypertension, and 291 with normal blood pressure. Only 31% of participants knew that hypertension adversely affects an individual's health and 7% knew the benefits of treating hypertension. Almost a third (30%) of those aware of their hypertensive status, and 48% overall, did not know any of the risk factors for hypertension. Being aware of one's hypertensive status (OR 2.51, 95% CI 1.44 to 4.39), being treated for hypertension, male sex, younger age, having some schooling, abdominal obesity and physical inactivity were associated with better knowledge of risk factors for hypertension., Conclusion: Knowledge of risk factors and consequences of hypertension in this disadvantaged population was poor. There was better knowledge of risk factors in some, but not all, people who were aware of having hypertension. Screening and targeted educational programmes are warranted in this population to improve health behaviours and reduce the consequences of hypertension., Competing Interests: Competing interests: None declared.
- Published
- 2019
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31. In silico design of a novel chimeric shigella IpaB fused to C terminal of clostridium perfringens enterotoxin as a vaccine candidate.
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Arabshahi S, Nayeri Fasaei B, Derakhshandeh A, and Novinrooz A
- Subjects
- Amino Acid Sequence, B-Lymphocytes immunology, B-Lymphocytes microbiology, Bacterial Proteins chemistry, Bacterial Proteins immunology, Binding Sites, Clostridium perfringens metabolism, Clostridium perfringens pathogenicity, Databases, Protein, Dysentery, Bacillary immunology, Dysentery, Bacillary prevention & control, Enterotoxins chemistry, Enterotoxins immunology, Epitopes, B-Lymphocyte genetics, Epitopes, B-Lymphocyte immunology, Escherichia coli genetics, Escherichia coli metabolism, Genetic Engineering methods, Humans, Models, Molecular, Plasmids chemistry, Plasmids metabolism, Protein Binding, Protein Conformation, alpha-Helical, Protein Conformation, beta-Strand, Protein Interaction Domains and Motifs, Recombinant Fusion Proteins chemistry, Recombinant Fusion Proteins immunology, Shigella immunology, Shigella pathogenicity, Shigella Vaccines genetics, Shigella Vaccines immunology, Bacterial Proteins genetics, Clostridium perfringens genetics, Enterotoxins genetics, Epitopes, B-Lymphocyte chemistry, Recombinant Fusion Proteins genetics, Shigella genetics, Shigella Vaccines chemistry
- Abstract
This study aimed to design a novel chimeric protein in silico to serve as a serotype-independent vaccine candidate against Shigella. The chimera contains amino acid residues 240-460 of Shigella invasion plasmid antigen B (IpaB) and the C-terminus of Clostridium perfringens enterotoxin (C-CPE). Amino acid sequences of 537 peptide linkers were obtained from two protein linker databases. 3D structures of IpaB-CPE
290-319 , IpaB-CPE184-319 , IpaB-CPE194-319 and 537 newly designed IpaB-linker-CPE290-319 constructs with varying linker regions were predicted. These predicted 3D structures were merged with the 3D structures of native IpaB240-460 , CPE194-319 , CPE184-319 and CPE290-319 to select the structure most similar to native IpaB and C-CPE. Several in silico tools were used to determine the suitability of the selected IpaB-C-CPE structure as a vaccine candidate. None of the 537 linkers was capable of preserving the native structure of CPE290-319 within the IpaB-linker-CPE290-319 structure. In silico analysis determined that the IpaB-CPE194-319 3D structure was the most similar to the 3D structure of the respective native CPE domain and that it was a stable chimeric protein exposing multiple B-cell epitopes. IpaB-CPE194-319 was designed for its capability to bind to human intestinal epithelial and M cells and to accumulate on these cells. The predicted B-cell epitopes are likely to be capable of inducing a mucosal antibody response in the human intestine against Shigella IpaB. This study also showed that the higher binding affinities of CPE184-319 and CPE194-319 to claudin molecules than those of CPE290-319 is the result of preserving the 3D structures of CPE184-319 and CPE194-319 when they are linked to the C-termini of other proteins.- Published
- 2018
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32. Dietary patterns and weight change: 15-year longitudinal study in Australian adults.
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Arabshahi S, Ibiebele TI, Hughes MCB, Lahmann PH, Williams GM, and van der Pols JC
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- Adult, Aged, Australia epidemiology, Body Mass Index, Dietary Fats administration & dosage, Female, Follow-Up Studies, Fruit, Humans, Life Style, Longitudinal Studies, Male, Meat, Middle Aged, Nutrition Assessment, Principal Component Analysis, Risk Factors, Sample Size, Socioeconomic Factors, Surveys and Questionnaires, Vegetables, Diet, Obesity epidemiology, Weight Gain
- Abstract
Background: Dietary intake is one of the most modifiable risk factors associated with obesity. However, data on the relationship between dietary patterns and long-term weight change are limited., Purpose: We therefore investigated the association between dietary patterns and 15-year weight change in a sample of 1186 Australian adults (1992-2007)., Methods: We measured body weight and collected data on socio-demographic and lifestyle characteristics in 1992 and 2007. Applying principal component analysis to 38 food groups from a food frequency questionnaire collected at baseline, we identified two dietary patterns: 'meat-and-fat' and 'fruit-and-vegetable.' Using generalized estimating equations, multivariable regression models, stratified by sex, were adjusted for concurrent changes in socio-demographic and lifestyle variables., Results: The average increase in body weight of men in the highest tertile of the meat-and-fat pattern was more than twice that of men in the lowest tertile; mean weight change (95 % CI): 4.8 (-0.1, 9.7) kg versus 2.3 (-2.6, 7.1) kg, P-for-trend = 0.02. In contrast, average weight gain of men in the highest tertile of the fruit-and-vegetable pattern was only about half that of men in the lowest tertile; mean weight change (95 % CI): 2.9 (-2.0, 7.8) kg versus 5.4 (-1.5, 10.4) kg, P-for-trend = 0.02. Among women, dietary patterns were not related to weight change., Conclusions: These dietary patterns predict change in body weight in men, but not in women. In this cohort, a dietary pattern high in fruit and vegetables was related to less weight gain in men than a dietary pattern high in meat and fat.
- Published
- 2017
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33. Factors associated with awareness, treatment and control of hypertension in a disadvantaged rural Indian population.
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Busingye D, Arabshahi S, Evans RG, Srikanth VK, Kartik K, Kalyanram K, Riddell MA, Zhu X, Suresh O, and Thrift AG
- Subjects
- Aged, Blood Pressure drug effects, Blood Pressure Determination methods, Female, Health Knowledge, Attitudes, Practice, Health Services Accessibility statistics & numerical data, Humans, India epidemiology, Male, Middle Aged, Needs Assessment, Prevalence, Risk Factors, Rural Population statistics & numerical data, Socioeconomic Factors, Antihypertensive Agents therapeutic use, Hypertension diagnosis, Hypertension drug therapy, Hypertension epidemiology
- Abstract
The aim of this study was to identify factors associated with awareness, treatment and control of hypertension in a rural setting in India. Following screening of the population, all individuals with hypertension (blood pressure (BP) ⩾140/90 mm Hg or taking antihypertensive medications) were invited to participate in this study. We measured BP, height, weight, skinfolds, waist and hip circumference, and administered a questionnaire to obtain information regarding socioeconomic and behavioural characteristics. Multivariable logistic regression was used to determine factors associated with awareness, treatment and control of hypertension. We recruited 277 individuals with hypertension. Awareness (43%), treatment (33%) and control (27%) of hypertension were poor. Greater distance to health services (odds ratio (OR) 0.56 (95% confidence interval (CI)) 0.32-0.98) was associated with poor awareness of hypertension while having had BP measured within the previous year (OR 4.72, 95% CI 2.71-8.22), older age and greater per cent body fat were associated with better awareness. Factors associated with treatment of hypertension were having had BP measured within the previous year (OR 6.18, 95% CI 3.23-11.82), age ⩾65 years, physical inactivity and greater per cent body fat. The only factor associated with control of hypertension was greater per cent body fat (OR 1.05, 95% CI 1.01-1.11). Improving geographic access and utilisation of health services should improve awareness and treatment of hypertension in this rural population. Further research is necessary to determine drivers of control.
- Published
- 2017
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34. In-silico design, expression, and purification of novel chimeric Escherichia coli O157:H7 OmpA fused to LTB protein in Escherichia coli.
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Novinrooz A, Zahraei Salehi T, Firouzi R, Arabshahi S, and Derakhshandeh A
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- Animals, Blotting, Western, Computer Simulation, Electrophoresis, Polyacrylamide Gel, Female, Mice, Mice, Inbred BALB C, Plasmids, Bacterial Outer Membrane Proteins genetics, Escherichia coli O157 genetics, Escherichia coli Proteins genetics, Recombinant Fusion Proteins genetics
- Abstract
E. coli O157:H7, one of the major EHEC serotypes, is capable of developing bloody diarrhea, hemorrhagic colitis (HC), and fatal hemolytic uremic syndrome (HUS) and is accompanied by high annual economic loss worldwide. Due to the increased risk of HC and HUS development following antibiotic therapy, the prevention of infections caused by this pathogen is considered to be one of the most effective ways of avoiding the consequences of this infection. The main aim of the present study was to design, express, and purify a novel chimeric protein to develope human vaccine candidate against E. coli O157:H7 containing loop 2-4 of E. coli O157:H7, outer membrane protein A (OmpA), and B subunit of E. coli heat labile enterotoxin (LTB) which are connected by a flexible peptide linker. Several online databases and bioinformatics software were utilized to choose the peptide linker among 537 analyzed linkers, design the chimeric protein, and optimize the codon of the relative gene encoding this protein. Subsequently, the recombinant gene encoding OmpA-LTB was synthesized and cloned into pET-24a (+) expression vector and transferred to E. coli BL21(DE3) cells. The expression of OmpA-LTB chimeric protein was then carried out by induction of cultured E. coli Bl21 (DE3) cells with 1mM isopropyl-β-D-thiogalactopyranoside (IPTG). The purification of OmpA-LTB was then performed by nickel affinity chromatography. Expression and purification were analyzed by sodium dodecyl sulphate poly acrylamide gel electrophoresis. Moreover, the identity of the expressed protein was analyzed by western blotting. SDS-PAGE and western immunoblotting confirmed the successful expression of a 27 KDa recombinant protein after 24 hours at 37°C post-IPTG induction. OmpA-LTB was then successfully purified, using nickel affinity chromatography under denaturing conditions. The yield of purification was 12 mg per liter of culture media. Ultimately, we constructed the successful design and efficient expression and purification of OmpA-LTB divalent under the above-mentioned conditions.
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- 2017
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35. Dietary behaviours, weight loss attempts and change in waist circumference: 15-year longitudinal study in Australian adults.
- Author
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Arabshahi S, Lahmann PH, Hughes MC, Williams GW, and van der Pols JC
- Subjects
- Australia, Humans, Feeding Behavior, Waist Circumference, Weight Loss
- Abstract
Background and Objectives: Dietary behaviours are suitable as clearly identifiable targets of dietary counselling to prevent weight gain. We therefore investigated associations between dietary behaviours, weight loss attempts and waist circumference change., Methods and Study Design: Participants were a community-based sample population residing in Nambour, Australia, including 1,317 adults, aged 25-75 years at baseline. Waist circumference was measured in 1992 and 2007, and dietary behaviours data were derived concurrently from repeated self-completed short dietary questions. Multivariable models, stratified by sex, were adjusted for potential confounders., Results: In men, consumption of visible fat on meat and in women, weight loss attempts in the last 10 years were the most important predictors of waist circumference gain independent of socio-demographic and lifestyle characteristics and energy intake. Men who consumed most visible fat on meat had a 2.6 times larger yearly increase in waist circumference than men who tended to cut the fat off meat: 0.47 (95% CI 0.23, 0.72) vs 0.18 (95% CI 0.01, 0.34) cm/year, p=0.01. Women who reported that they were always trying to lose weight had a 2.7 times larger yearly increase in waist circumference than women who never tried to lose weight: 0.78 (0.54, 1.02) vs 0.29 (0.06, 0.52) cm/year, p=0.0001. Other dietary behaviours were not associated with change in waist circumference., Conclusions: Consumption of visible fat on meat by men and more frequent attempts to lose weight by women were main dietary behaviours associated with gain in abdominal adiposity in Australian adults.
- Published
- 2017
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36. Cluster randomised feasibility trial to improve the Control of Hypertension In Rural India (CHIRI): a study protocol.
- Author
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Riddell MA, Joshi R, Oldenburg B, Chow C, Thankappan KR, Mahal A, Thomas N, Srikanth VK, Evans RG, Kalyanram K, Kartik K, Maulik PK, Arabshahi S, Varma RP, Guggilla RK, Suresh O, Mini GK, D'Esposito F, Sathish T, Alim M, and Thrift AG
- Subjects
- Adult, Cluster Analysis, Community Health Services organization & administration, Cross-Sectional Studies, Feasibility Studies, Female, Focus Groups, Humans, Hypertension epidemiology, India epidemiology, Male, Middle Aged, Patient Acceptance of Health Care statistics & numerical data, Quality of Life, Rural Population, Self Care, Socioeconomic Factors, Health Services Accessibility organization & administration, Hypertension prevention & control, Hypertension therapy, Rural Health Services organization & administration
- Abstract
Introduction: Hypertension is emerging in rural populations of India. Barriers to diagnosis and treatment of hypertension may differ regionally according to economic development. Our main objectives are to estimate the prevalence, awareness, treatment and control of hypertension in 3 diverse regions of rural India; identify barriers to diagnosis and treatment in each setting and evaluate the feasibility of a community-based intervention to improve control of hypertension., Methods and Analysis: This study includes 4 main activities: (1) assessment of risk factors, quality of life, socioeconomic position and barriers to changes in lifestyle behaviours in ∼14 500 participants; (2) focus group discussions with individuals with hypertension and indepth interviews with healthcare providers, to identify barriers to control of hypertension; (3) use of a medicines-availability survey to determine the availability, affordability and accessibility of medicines and (4) trial of an intervention provided by Accredited Social Health Activists (ASHAs), comprising group-based education and support for individuals with hypertension to self-manage blood pressure. Wards/villages/hamlets of a larger Mandal are identified as the primary sampling unit (PSU). PSUs are then randomly selected for inclusion in the cross-sectional survey, with further randomisation to intervention or control. Changes in knowledge of hypertension and risk factors, and clinical and anthropometric measures, are assessed. Evaluation of the intervention by participants provides insight into perceptions of education and support of self-management delivered by the ASHAs., Ethics and Dissemination: Approval for the overall study was obtained from the Health Ministry's Screening Committee, Ministry of Health and Family Welfare (India), institutional review boards at each site and Monash University. In addition to publication in peer-reviewed articles, results will be shared with federal, state and local government health officers, local healthcare providers and communities., Trial Registration Number: CTRI/2016/02/006678; Pre-results., Competing Interests: Conflicts of Interest: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)
- Published
- 2016
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37. Novel dietary intake assessment in populations with poor literacy.
- Author
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Subasinghe AK, Thrift AG, Evans RG, Arabshahi S, Suresh O, Kartik K, Kalyanram K, and Walker KZ
- Subjects
- Adult, Aged, Aged, 80 and over, Body Mass Index, Energy Intake, Female, Food, Humans, India, Male, Mental Recall, Middle Aged, Poverty, Pregnancy, Rural Population, Surveys and Questionnaires, Young Adult, Diet, Diet Records, Literacy, Nutrition Assessment
- Abstract
Background and Objectives: Cultural and/or environmental barriers make the assessment of dietary intake in rural populations challenging. We aimed to assess the accuracy of a meal recall questionnaire, adapted for use with impoverished South Indian populations living in rural areas., Methods and Study Design: Dietary data collected by recall versus weighed meals were compared. Data were obtained from 45 adults aged 19-85 years, living in rural Andhra Pradesh, who were recruited by convenience sampling. Weighed meal records (WMRs) were conducted in the household by a researcher aided by a trained field worker. The following day, field workers conducted a recall interview with the same participant. Eight life size photographs of portions of South Indian foods were created to aid each participant's recall and a database of nutrients was developed to calculate nutrient intake. Pearson correlations were used to assess the strength of associations between intake of energy and nutrients calculated from meal recalls versus WMRs. Least products regression was conducted to examine fixed and proportional bias. Bland-Altman plots were constructed to measure systematic or differential bias., Results: Significant correlations were observed between estimates for energy and nutrients obtained by the two methods (r2=0.19-0.67, p<0.001). No systematic bias was detected by Bland-Altman plots. Recall method underestimated the intake of protein and fat in a manner proportional to the level of intake., Conclusions: Our culturally adapted meal recall questionnaire provides an accurate measure for assessment of the intake of energy, macronutrients and some micronutrients in rural Indian populations.
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- 2016
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38. Association between salt and hypertension in rural and urban populations of low to middle income countries: a systematic review and meta-analysis of population based studies.
- Author
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Subasinghe AK, Arabshahi S, Busingye D, Evans RG, Walker KZ, Riddell MA, and Thrift AG
- Subjects
- Causality, Humans, Incidence, Poverty, Risk Factors, Socioeconomic Factors, Developing Countries statistics & numerical data, Hypertension epidemiology, Rural Population statistics & numerical data, Sodium Chloride, Dietary administration & dosage, Urban Population statistics & numerical data
- Abstract
Background and Objectives: The prevalence of hypertension, the greatest contributor to mortality globally, is increasing in low-and-middle income countries (LMICs). In urban regions of LMICs, excessive salt intake is associated with increased risk of hypertension. We aimed to determine whether this is the case in rural regions as well., Methods and Study Design: We performed a meta-analysis of studies in rural and urban areas of LMICs in which the association of salt and hypertension were assessed using multivariable models., Results: We identified 18 studies with a total of 134,916 participants. The prevalence of high salt intake ranged from 21.3% to 89.5% in rural and urban populations. When salt was analysed as a continuous variable, a greater impact of salt on hypertension was found in urban (n=4) (pooled effect size (ES) 1.42, 95% CI 1.19, 1.69) than in rural populations (n=4) (pooled ES 1.07, 95% CI 1.04, 1.10, p for difference <0.001). In studies where salt was analysed continuously, a greater impact of salt on hypertension was observed in lean rural populations (BMI <23 kg/m2) than in non-lean rural populations (BMI >=23 kg/m2, p for difference <0.001)., Conclusions: The prevalence of high salt intake is similar in rural and urban regions. Excessive salt intake has a greater impact on the prevalence of hypertension in urban than rural regions. BMI appears to modify the relationship between salt and hypertension in rural populations.
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- 2016
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39. Authors' Response to: Data sources for measuring the socioeconomic gradient of hypertension in rural populations of low- and middle-income countries.
- Author
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Busingye D, Riddell MA, Evans RG, Arabshahi S, Subasinghe AK, and Thrift AG
- Subjects
- Humans, Educational Status, Hypertension, Income, Rural Health
- Published
- 2015
- Full Text
- View/download PDF
40. Predictors of change in weight and waist circumference: 15-year longitudinal study in Australian adults.
- Author
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Arabshahi S, Lahmann PH, Williams GM, and van der Pols JC
- Published
- 2015
- Full Text
- View/download PDF
41. Distribution of virulence genes and multiple drug-resistant patterns amongst different phylogenetic groups of uropathogenic Escherichia coli isolated from patients with urinary tract infection.
- Author
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Derakhshandeh A, Firouzi R, Motamedifar M, Motamedi Boroojeni A, Bahadori M, Arabshahi S, Novinrooz A, and Heidari S
- Subjects
- Anti-Bacterial Agents pharmacology, Disk Diffusion Antimicrobial Tests, Drug Resistance, Multiple, Bacterial, Female, Genes, Bacterial, Humans, Male, Phylogeny, Polymerase Chain Reaction, Uropathogenic Escherichia coli drug effects, Uropathogenic Escherichia coli isolation & purification, Virulence genetics, Escherichia coli Infections microbiology, Urinary Tract Infections microbiology, Uropathogenic Escherichia coli genetics, Uropathogenic Escherichia coli pathogenicity, Virulence Factors genetics
- Abstract
A total of 85 Uropathogenic Escherichia coli (UPEC) isolates were screened against ceftiofur, oxacillin, nitrofurantoin and lincospectin using Kirby-Bauer disc diffusion method, following CLSI guidelines. Prevalence of virulent factor genes amongst the isolates was determined by PCR, using gene-specific primers against the different virulent factors. Statistical analysis of the data was performed using SPSS software. The prevalence of traT, ompT, Iss, malX and ibeA genes was 47.1%, 38.8%, 20%, 16.5% and 9.4%, respectively. The most prevalent gene in group A and D was traT, whilst in group B2 was Iss. The highest resistance has been shown against oxacillin (98.8%), followed by ceftiofur (77.6%), whilst resistance to lincospectin (2.4%) and nitrofurantoin (12.9%) had the lowest frequencies. Multidrug resistance was shown in 82.35% of the isolates, whilst this study recommend lincospectin and nitrofurantoin as choice drugs for treatment, but more investigation of the bacterial pathogenicity associated with urinary tract infection (UTI) may contribute to a better medical intervention., (© 2014 The Society for Applied Microbiology.)
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- 2015
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42. Virulence Characteristics and Antibiotic Resistance Patterns among Various Phylogenetic Groups of Uropathogenic Escherichia coli Isolates.
- Author
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Derakhshandeh A, Firouzi R, Motamedifar M, Arabshahi S, Novinrooz A, Boroojeni AM, Bahadori M, and Heidari S
- Subjects
- Anti-Bacterial Agents pharmacology, Humans, Phylogeny, Uropathogenic Escherichia coli classification, Uropathogenic Escherichia coli genetics, Virulence genetics, Drug Resistance, Bacterial genetics, Escherichia coli Infections microbiology, Urinary Tract Infections microbiology, Uropathogenic Escherichia coli drug effects, Uropathogenic Escherichia coli pathogenicity
- Abstract
The aim of this study was to determine the resistance patterns of uropathogenic Escherichia coli (UPEC) isolates and to investigate the frequency of several virulence genes, including fimH, papA, hlyD, cnf-1, sitA, and tsh, among various phylogenetic groups of UPEC isolates. A total of 85 E. coli isolates were recovered from urine samples from outpatients with a clinical diagnosis of uncomplicated urinary tract infections. A molecular approach to examine the antimicrobial resistance patterns was employed using PCR and the disc diffusion method. The detected frequencies of the virulence factor genes determined using PCR were: fimH (34.1%), papA (9.4%), hlyD (21.2%), cnf-1 (3.5%), sitA (15.3%), and tsh (27.1%). These results revealed that the isolates were resistant to trimethoprim-sulfamethoxazole (SXT) (74.1%), cefotaxime (CTX) (68.2%), and amoxicillin-clavulanic acid (AMC) (94.1%), and they were relatively less resistant to N (56.5%). According to these results, further investigation is needed to determine exactly whether or not SXT, CTX, and AMC are appropriate antibiotics for the treatment of UPEC infections in southern Iran. Although these results demonstrate that fimH is the most frequent virulence gene among UPEC isolates, the high prevalence of isolates that do not encode fimH (75.9%) and the relatively low frequency of isolates that carry other virulence genes require further investigation to clarify the role of the other potential virulence factors in the pathogenesis of these isolates.
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- 2015
- Full Text
- View/download PDF
43. Rejoinder: Socioeconomic gradients and hypertension in low- and middle-income countries: a straw man and no solutions.
- Author
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Busingye D, Evans RG, Arabshahi S, Subasinghe AK, Riddell MA, and Thrift AG
- Subjects
- Humans, Educational Status, Hypertension, Income, Rural Health
- Published
- 2014
- Full Text
- View/download PDF
44. Do the socioeconomic and hypertension gradients in rural populations of low- and middle-income countries differ by geographical region? A systematic review and meta-analysis.
- Author
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Busingye D, Arabshahi S, Subasinghe AK, Evans RG, Riddell MA, and Thrift AG
- Subjects
- Humans, Occupations, Population Surveillance, Poverty, Rural Population, Social Class, Socioeconomic Factors, Educational Status, Hypertension, Income, Rural Health
- Abstract
Background: Of the 1 billion people with hypertension globally, two-thirds reside in low- and middle-income countries (LMICs). The risk of hypertension in LMICs is thought to be positively associated with socioeconomic status (SES). However, recent studies have provided data inconsistent with this concept. Thus, we assessed the association between SES and hypertension in rural populations of LMICs. Further, we explored whether this association differs according to geographical region., Methods: Through a search of databases we identified population-based studies that presented risk estimates for the association between SES, or any of its proxies, and hypertension. Meta-analyses were conducted using a random effects model., Results: Overall, no association was detected between educational status and hypertension, whereas a positive association was observed with income. Interestingly, educational status was inversely associated with hypertension in East Asia {effect size [ES] 0.82 [95% confidence interval (CI) 0.78, 0.87]} but positively associated in South Asia [ES 1.28 (95% CI 1.14, 1.43)]. Higher income, household assets or social class were positively associated with hypertension in South Asia whereas no association was detected in East Asia and Africa. Compared with other occupations, farmers or manual labourers were associated with a lower risk for hypertension. Further, in regions such as Latin America, few studies were identified that fulfilled our inclusion criteria., Conclusions: We provide evidence that the association between hypertension and SES in rural populations of LMICs in Asia varies according to geographical region. This has important implications for targeting intervention strategies aimed at high-risk populations in different geographical regions., (© The Author 2014; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.)
- Published
- 2014
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45. Adiposity has a greater impact on hypertension in lean than not-lean populations: a systematic review and meta-analysis.
- Author
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Arabshahi S, Busingye D, Subasinghe AK, Evans RG, Riddell MA, and Thrift AG
- Subjects
- Body Mass Index, Female, Humans, Hypertension physiopathology, Male, Obesity physiopathology, Risk, Rural Population, Thinness, Urban Population, Waist Circumference, Adiposity, Hypertension complications, Obesity complications
- Abstract
More than 75 % of people with hypertension live in low-to-middle income countries (LMICs). Based on the mismatch theory of developmental origins of disease, we hypothesised that the impact of adiposity on hypertension is augmented in lean compared with not-lean populations in rural areas of LMICs (RLMICs). We reviewed studies from RLMICs in which the association between body mass index (BMI) or waist circumference (WC) and hypertension was assessed using multivariable models. Applying random effect models, we conducted separate meta-analyses, depending on whether BMI/WC was assessed as a continuous or categorical variable. In each analysis, the studies were ranked by the mean BMI of the total population. Those populations with a mean BMI below the median were categorised as lean and those above the median as not-lean. We identified 46 studies of BMI and 12 of WC. The risk of hypertension was greater in lean than in not-lean populations. Obese males in lean populations were 45 % more likely to be hypertensive compared to obese males in not-lean populations, ratio of the two effect sizes: 1.45 (95 % CI 1.04, 2.03), p = 0.027. Also, individuals with WC above normal in lean populations were 52 % more likely to be hypertensive than their counterparts in not-lean populations, ratio of the two effect sizes: 1.52 (95 % CI 1.06, 2.17), p = 0.021. We conclude that the risk of hypertension associated with adiposity is greater in lean than in not-lean populations. This provides further evidence for the mismatch theory and highlights the need for strategies to improve nutrition in disadvantaged RLMICs.
- Published
- 2014
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46. Predictors of change in weight and waist circumference: 15-year longitudinal study in Australian adults.
- Author
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Arabshahi S, Lahmann PH, Williams GM, and van der Pols JC
- Subjects
- Adult, Aged, Australia, Body Mass Index, Diet, Female, Follow-Up Studies, Health Behavior, Humans, Life Style, Linear Models, Longitudinal Studies, Male, Middle Aged, Motor Activity, Multivariate Analysis, Parity, Pregnancy, Socioeconomic Factors, Surveys and Questionnaires, Body Weight, Waist Circumference
- Abstract
Background/objectives: This study examines which socio-demographic and lifestyle characteristics are associated with weight and waist circumference (WC) change in a cohort of Australian adults over a 15-year period (1992-2007). Further, it tests the effect of period of birth (birth cohort) on mean weight and WC at two time points, 15 years apart., Subjects/methods: Up to three repeated measures of weight (n=1437) and WC (n=1317) were used. Self-reported data on socio-demographic and lifestyle characteristics were derived from repeated questionnaires. Multivariable models, stratified by sex, were adjusted for potential confounders., Results: Participants born more recently were heavier, on average, than those in the same age group 15 years earlier, but there was no such secular trend in WC. Age at baseline was associated with change in weight and WC, but the pattern was different: participants gained weight up to age 55 years, while WC gain continued to 65 years. In women, higher level of recreational physical activity was associated with lower WC gain (P<0.05). Parity was also associated with WC change in women (P<0.05), but there was no linear trend., Conclusions: Age was the most important factor associated with change in weight and WC in both sexes, apparently reducing the influence of all potential covariates. Among women, physical activity and parity were also associated with change in weight and WC. This study provides longitudinal evidence to support public health efforts that address the continuous increases in average weight and WC of many populations around the world.
- Published
- 2014
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47. Discharge is a critical time to influence 10-year use of secondary prevention therapies for stroke.
- Author
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Thrift AG, Kim J, Douzmanian V, Gall SL, Arabshahi S, Loh M, and Evans RG
- Subjects
- Aged, Antihypertensive Agents therapeutic use, Female, Follow-Up Studies, Humans, Incidence, Logistic Models, Male, Patient Compliance, Stroke drug therapy, Survival Analysis, Survivors, Victoria epidemiology, Patient Discharge statistics & numerical data, Secondary Prevention methods, Stroke prevention & control
- Abstract
Background and Purpose: When optimally managed, patients with stroke are less likely to have further vascular events. We aimed to identify factors associated with optimal use of secondary prevention therapies in long-term survivors of stroke., Methods: We carefully documented discharge medications at baseline and self-reported use of medications at annual follow-up in the Northeast Melbourne Stroke Incidence Study (NEMESIS). We defined optimal medication use when patients reported taking (1) antihypertensive agents and (2) statin and antithrombotic agents (ischemic stroke only). Logistic regression was used to assess factors associated with optimal medication use between 2 and 10 years after stroke., Results: We recruited 1241 patients with stroke. Optimal prescription at discharge from hospital was the most important factor associated with optimal medication use at each time point: odds ratio (OR), 32.2 (95% confidence interval [CI], 13.6-76.1) at 2 years; OR, 7.86 (95% CI, 4.48-13.8) at 5 years (425 of 505 survivors); OR, 6.04 (95% CI, 3.18-11.5) at 7 years (326 of 390 survivors); and OR, 2.62 (95% CI, 1.19-5.77) at 10 years (256 of 293 survivors). Associations were similar in men and women. The association between optimal prescription at discharge and optimal medication use at each time point was greater in those who were not disadvantaged, particularly women., Conclusions: Prescription of medications at hospital discharge was the strongest predictor of ongoing medication use in survivors of stroke, even at 10 years after stroke. Ensuring that patients with stroke are discharged on optimal medications is likely to improve their long-term management, but further strategies might be required among those who are disadvantaged.
- Published
- 2014
- Full Text
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48. Association between farming and chronic energy deficiency in rural South India.
- Author
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Subasinghe AK, Walker KZ, Evans RG, Srikanth V, Arabshahi S, Kartik K, Kalyanram K, and Thrift AG
- Subjects
- Adult, Anemia etiology, Anthropometry, Asthenia etiology, Chronic Disease, Cross-Sectional Studies, Eating, Female, Hemoglobins analysis, Humans, India epidemiology, Male, Motor Activity physiology, Nutrition Disorders complications, Prevalence, Socioeconomic Factors, Agriculture statistics & numerical data, Anemia epidemiology, Asthenia epidemiology, Nutrition Disorders epidemiology, Rural Population statistics & numerical data
- Abstract
Objective: To examine factors associated with chronic energy deficiency (CED) and anaemia in disadvantaged Indian adults who are mostly involved in subsistence farming., Design: A cross-sectional study in which we collected information on socio-demographic factors, physical activity, anthropometry, blood haemoglobin concentration, and daily household food intake. These data were used to calculate body mass index (BMI), basal metabolic rate (BMR), daily energy expenditure, and energy and nutrient intake. Multivariable backward stepwise logistic regression was used to assess socioeconomic and lifestyle factors associated with CED (defined as BMI<18 kg/m²) and anaemia., Setting: The study was conducted in 12 villages, in the Rishi Valley, Andhra Pradesh, India., Subjects: Individuals aged 18 years and above, residing in the 12 villages, were eligible to participate., Results: Data were available for 1178 individuals (45% male, median age 36 years (inter quartile range (IQR 27-50)). The prevalence of CED (38%) and anaemia (25%) was high. Farming was associated with CED in women (2.20, 95% CI: 1.39-3.49) and men (1.71, 95% CI: (1.06-2.74). Low income was also significantly associated with CED, while not completing high school was positively associated with anaemia. Median iron intake was high: 35.7 mg/day (IQR 26-46) in women and 43.4 mg/day (IQR 34-55) in men., Conclusions: Farming is an important risk factor associated with CED in this rural Indian population and low dietary iron is not the main cause of anaemia. Better farming practice may help to reduce CED in this population.
- Published
- 2014
- Full Text
- View/download PDF
49. Is stroke incidence in low- to middle-income countries driven by economics?
- Author
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Thrift AG and Arabshahi S
- Subjects
- Developing Countries statistics & numerical data, Humans, Incidence, Risk Factors, Social Class, Stroke economics, Developing Countries economics, Income, Stroke epidemiology
- Abstract
The incidence of stroke in low- to middle-income countries now exceeds that in high-income countries. These low- to middle-income countries also have greater case fatality and a younger age of stroke onset, factors that contribute to a high stroke burden. Macroeconomic indicators of socioeconomic status, such as health expenditure, appear to be inversely associated with stroke incidence. However, there are often large socioeconomic gradients between regions such as between urban and rural regions. This article emphasizes that macroeconomic indicators are likely to mask regional disparities in stroke incidence. Public health messages and prevention strategies must therefore be targeted regionally rather than nationwide. Without a comprehensive and multifaceted approach to prevention, the epidemic of stroke will continue., (© 2012 The Authors. International Journal of Stroke © 2012 World Stroke Organization.)
- Published
- 2012
- Full Text
- View/download PDF
50. Diet quality and change in anthropometric measures: 15-year longitudinal study in Australian adults.
- Author
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Arabshahi S, van der Pols JC, Williams GM, Marks GC, and Lahmann PH
- Subjects
- Adult, Aged, Anthropometry, Australia, Body Mass Index, Feeding Behavior, Female, Humans, Longitudinal Studies, Male, Middle Aged, Multivariate Analysis, Obesity prevention & control, Sex Factors, Surveys and Questionnaires, Waist Circumference, Diet, Obesity physiopathology
- Abstract
Evidence from longitudinal studies on the association between diet quality and change in anthropometric measures is scarce. We therefore investigated the relationship between a recently developed food-based dietary index and change in measured BMI and waist circumference (WC) in Australian adults (1992-2007). We used data from the Australian population-based Nambour Skin Cancer Study comprising 1231 adults aged 25-75 years at baseline (1992). We applied generalised estimating equations (GEE) to examine the association between diet quality and change in anthropometric measures. Dietary intake was assessed by an FFQ in 1992, 1996 and 2007. Diet quality was estimated using the dietary guideline index (DGI), developed to reflect the dietary guidelines for Australian adults; a higher score indicating increased compliance. Multivariable models, stratified by sex, were adjusted for sociodemographic and lifestyle characteristics. We show that men with higher diet quality had a lower gain in BMI as compared to those with low diet quality during the 15-year follow-up. In a multivariable adjusted model, as compared to men in quartile 1 (reference), those in the highest quartile had the lowest gain in BMI (mean (95 % CI): 0.05 (0.00, 0.09) v. 0.11 (0.06, 0.16) kg/m2 per year, P =0.01). Diet quality was inversely, but non-significantly associated with change in WC. In women, DGI score was unrelated to change in any body measure. Energy underreporting did not explain the lack of association. We conclude that adherence to a high-quality diet according to Australian dietary guidelines leads to lower gain in BMI and WC in middle-aged men, but not in women.
- Published
- 2012
- Full Text
- View/download PDF
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