1,112 results on '"S. Chhabra"'
Search Results
102. Methods to extract molecular and bulk chemical information from series of complex mass spectra with limited mass resolution
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P. S. Chhabra, Douglas R. Worsnop, Reddy L. N. Yatavelli, Manjula R. Canagaratna, Harald Stark, Joel R. Kimmel, S. Thompson, Michael J. Cubison, Jose L. Jimenez, and John T. Jayne
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Chemical ionization ,010504 meteorology & atmospheric sciences ,Resolution (mass spectrometry) ,Series (mathematics) ,Chemistry ,Analytical chemistry ,010501 environmental sciences ,Condensed Matter Physics ,Mass spectrometry ,01 natural sciences ,Chemical space ,Spectral line ,Computational physics ,Ion ,Mass spectrum ,Physical and Theoretical Chemistry ,Instrumentation ,Spectroscopy ,0105 earth and related environmental sciences - Abstract
The resolution of mass spectrometers is often insufficient to conclusively identify all peaks that may be present in recorded spectra. Here, we present new methods to extract consistent molecular and bulk level chemical information by constrained fitting of series of complex organic mass spectra with multiple overlapping peaks. Possible individual peaks in a group of overlapping peaks are identified by both defining a chemical space and by free peak fitting. If simply all possible formulas from the chemical space would be used to fit each peak, the result would not be well constrained. The free peak fitting algorithm provides information about likely peak locations. A new algorithm then reconciles the results of both methods and produces a final peak list for use in subsequent fitting, while using all available experimental constraints. Comparison to ultra-high resolution data suggests that the real peak density is substantially higher than can be resolved with the instrument resolution. Bulk chemical properties such as carbon number (nC) and carbon oxidation state (OS C ) can be calculated from the fit results. For mixtures of compounds dominated by C, H, O and N, bulk properties can be reliably extracted, even though some formula assignments may remain uncertain. This ability to retrieve correct bulk parameters even if not all assigned formulas are correct originates from the relationship between mass defects of individual peaks and the chemical parameters under our CHON composition assumptions. Retrieving consistent bulk parameters across series of many mass spectra is essential for extracting time trends, e.g. for field measurements taking place over several weeks. We illustrate the fitting method using a sample data set from a chemical ionization mass spectrometer with a resolution of approximately 4000 (M/dM), operated using acetate reagent ions. Spectral simulation experiments validate the analysis method by showing good agreement of intensities for many specific ions, as well as for bulk chemical parameters. An alternative method to directly extract bulk chemical information from the raw spectra without the need of any peak assignment or peak fitting is also introduced, which shows good agreement with the peak fitting results. The latter method can be applied very rapidly without the need for complex analysis procedures, e.g. as a quick online diagnostic during data acquisition.
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- 2015
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103. Influence of socio-economic status on access to different components of SCI management across Indian population
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H S Chhabra and A M Bhalla
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Adult ,Male ,medicine.medical_specialty ,media_common.quotation_subject ,India ,Poison control ,Social class ,Suicide prevention ,Occupational safety and health ,Young Adult ,Surveys and Questionnaires ,Injury prevention ,medicine ,Humans ,Socioeconomic status ,Spinal Cord Injuries ,Retrospective Studies ,media_common ,business.industry ,Disease Management ,Human factors and ergonomics ,General Medicine ,Social Class ,Neurology ,Physical therapy ,Female ,Neurology (clinical) ,business ,Welfare ,Demography - Abstract
To assess the influence of financial constraints on access to different components of spinal cord injury (SCI) management in various socio-economic strata of the Indian population. Indian Spinal Injuries Centre (ISIC). One hundred fifty SCI individuals who came for follow-up at ISIC between March 2009 and March 2013 with at least 1 year of community exposure after discharge were included in the study. Socio-economic classification was carried out according to the Kuppuswamy scale, a standard scale for the Indian population. A self-designed questionnaire was administered. No sample was available from the lower group. There was a statistically significant difference (P
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- 2015
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104. Functional Properties of Select Dry Bean Seeds and Flours
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Sahil, Gupta, Guneet S, Chhabra, Changqi, Liu, Jasamrit S, Bakshi, and Shridhar K, Sathe
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Chemical Phenomena ,Food Handling ,Food, Preserved ,Seeds ,Water ,Fabaceae ,Lens Plant ,Soybeans - Abstract
Select functional properties of 21 dry beans and soybean seeds and their corresponding flours were evaluated. Among the tested seeds, dark-red and light-red kidney beans had larger length (L)/breadth (B) ratios than the rest. Lentil seeds were the smallest (L/B = 0.98), thinnest (2.23 mm), and lightest (density 1.14 g/cmUnderstanding the functional properties of the dry bean seeds and flours is important for designing handling, transportation, storage, and processing methods for these beans and in guiding the selection of appropriate dry bean flours as food ingredients.
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- 2018
105. Birth place, practices - a research agenda
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S. Chhabra
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Birth Place ,Child care ,Paediatric neurology ,Reproductive health care ,Pediatric rehabilitation ,Political science ,medicine ,Public administration ,medicine.disease_cause ,Vaginal infections ,Pediatric cardiology ,Paediatric anaesthesia - Published
- 2018
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106. Lack of Small Family Norms in low Resource Settings
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S. Chhabra
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Gender equity ,Low resource ,business.industry ,media_common.quotation_subject ,Vasectomy ,Fertility ,law.invention ,Condom ,Sterilization (medicine) ,law ,Medicine ,Local language ,business ,Socioeconomic status ,Demography ,media_common - Abstract
Background: Fertility is determined by many factors, so there are variations in pregnancies, births. Family size varies within, between societies. Socioeconomic status, environment, culture, education, couples’ understanding, every day life play vital roles. Objectives: Present study was done to know sterilization practices by couples of rural, tribal communities of Melghat region Amravati, Maharashtra, India. Materials and methods: Study subjects were 520 married women of 20-35 years. If non pregnant then with one or more births, at least one live child. If pregnant then with second pregnancy onwards, willing to give consent for providing desired information as per predesigned, pretested questionnaire in local language. Results: Of 520 women, 198 had one live child, no one had sterilization. There was hardly any birth spacing/planning, except occasional use of condom by educated, very few. Of 322 women with 2 or more live children, only 77 (26%) had sterilization, no vasectomy. Two hundred women had 2 live children, 43 (21.5%) of them had sterilization, 122 had >2 live children, only 34 (28%) had sterilization. Only 17 (13.9%) of 122 women had sterilization with 1 male and 1 female child, none with no male child, irrespective of number of female children, Mostly women had sterilization after 3 male children, 60 of 77 (77.92%) had sterilization after 2 or more male children. Conclusion: Fertility was high creating more problems for tribal communities with extremely low resources. Only women underwent sterilization. Not only son was essential, there was desire of more than 2 male children. It is essential to create awareness about advantages of small families for health, social, economic aspects and about gender equity.
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- 2018
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107. Awareness of Reproductive Health amongst Rural School Dropout Girls
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S. Chhabra and Annapurna
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Sexually transmitted disease ,medicine.medical_specialty ,business.industry ,media_common.quotation_subject ,Shyness ,medicine.disease ,law.invention ,Menstruation ,Acquired immunodeficiency syndrome (AIDS) ,Condom ,law ,Family medicine ,Pill ,medicine ,Menarche ,Psychology ,business ,media_common ,Reproductive health - Abstract
Introduction: In schools adolescents get opportunities to share personal perceptions, doubts with peers, teachers, not possible if they do not go to school. Lack of awareness, information about reproductive health might lead to problems during adolescence, future life. Objectives: To know awareness of reproductive health, among rural school dropout girls. Materials and methods: Present study was carried out in 772 rural adolescent school dropout girls, neither going to school, nor on fixed job, nor married from 53 villages near medical institute. Because of resource crunch, study visits were clubbed with nurse midwives’ visits to villages for community based maternal care. After consent information was collected by interviews in privacy, mostly at girls homes with pre-tested questionnaire, in local language by social worker. Results: Of 772, girls 760 had gone to schools, stopped, (drop outs), 12 had never gone. In 16.70% of 772 reason was financial, 20.33% said that school was far off, 20.20% were not allowed to go because they were girls, 25.51% had other reasons. 17.05% of 760 discontinued because had failed in examination, could not study, Only 58.03% of 772 girls had heard of menstruation pre menarche. Meaning of menarche was known to 41.96%. Care to be taken during menstruation was known only to 15.96% pre menarche. When menstruation occurred reaction was fear in 26.55%, anxiety in 22.40%, shyness 18.31%, irritability 13.86%. However 18.91% had no reaction, with no difference whether they knew or not. Whatever little bit girls knew, 18.97% were told by mothers. 18.97% friends, 14.73% doctors in meets/programs. Over all 58.03% had heard about contraception. Ninety (20.08)% girls had some knowledge of oral contraceptive pills, 18.97% had heard about condom. Knowledge about HIV AIDS was in 58.3%, 27.00% b from radio, 26.78% television, 23.88% by doctors. Only 38.61% knew that HIV was sexually transmitted disease. Knowledge about sexual relationship was only in seven girls. Conclusion: A wholesome approach for community based awareness encompassing basics in reproductive health is essential, more so because some rural girls never go to school many stop going early in their life due to various reasons.
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- 2018
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108. Application of high-resolution time-of-flight chemical ionization mass spectrometry measurements to estimate volatility distributions of α-pinene and naphthalene oxidation products
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J. T. Jayne, Joel R. Kimmel, Harald Stark, Paul Davidovits, Andrew T. Lambe, Manjula R. Canagaratna, Timothy B. Onasch, P. S. Chhabra, and D. R. Worsnop
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chemistry.chemical_classification ,Atmospheric Science ,Chemical ionization ,010504 meteorology & atmospheric sciences ,Double bond ,lcsh:TA715-787 ,Chemistry ,lcsh:Earthwork. Foundations ,Environmental chamber ,Analytical chemistry ,010501 environmental sciences ,7. Clean energy ,01 natural sciences ,lcsh:Environmental engineering ,Ion ,Time of flight ,chemistry.chemical_compound ,Fragmentation (mass spectrometry) ,13. Climate action ,Reagent ,lcsh:TA170-171 ,0105 earth and related environmental sciences ,Naphthalene - Abstract
Recent developments in high-resolution time-of-flight chemical ionization mass spectrometry (HR-ToF-CIMS) have made it possible to directly detect atmospheric organic compounds in real time with high sensitivity and with little or no fragmentation, including low-volatility, highly oxygenated organic vapors that are precursors to secondary organic aerosol formation. Here, using ions identified by high-resolution spectra from an HR-ToF-CIMS with acetate reagent ion chemistry, we develop an algorithm to estimate the vapor pressures of measured organic acids. The algorithm uses identified ion formulas and calculated double bond equivalencies, information unavailable in quadrupole CIMS technology, as constraints for the number of possible oxygen-containing functional groups. The algorithm is tested with acetate chemical ionization mass spectrometry (acetate-CIMS) spectra of O3 and OH oxidation products of α-pinene and naphthalene formed in a flow reactor with integrated OH exposures ranged from 1.2 × 1011 to 9.7 × 1011 molec s cm−3, corresponding to approximately 1.0 to 7.5 days of equivalent atmospheric oxidation. Measured gas-phase organic acids are similar to those previously observed in environmental chamber studies. For both precursors, we find that acetate-CIMS spectra capture both functionalization (oxygen addition) and fragmentation (carbon loss) as a function of OH exposure. The level of fragmentation is observed to increase with increased oxidation. The predicted condensed-phase secondary organic aerosol (SOA) average acid yields and O/C and H/C ratios agree within uncertainties with previous chamber and flow reactor measurements and ambient CIMS results. While acetate reagent ion chemistry is used to selectively measure organic acids, in principle this method can be applied to additional reagent ion chemistries depending on the application.
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- 2015
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109. Sequential Decision Process for Tradespace Exploration by Bounding Probabilistic Decision Criteria Using Mean-Risk Analysis
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Gordon P. Warn and Jaskanwal P. S. Chhabra
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Risk analysis ,Tradespace ,Operations research ,Computer science ,Process (engineering) ,Bounding overwatch ,Probabilistic logic ,Multiple-criteria decision analysis ,Sequential decision - Abstract
Uncertainty is an integral part of decision making. While performing tradespace analysis multiple design alternatives need to be compared with respect to uncertain decision criteria in order to identify non-dominated design alternatives. However when the decision criteria is obtained from a computationally intensive numerical analysis or from an experimental analysis it might not be feasible to precisely derive distributions of the decision criteria for all design alternatives in the tradespace. In this study it is hypothesized that the availability of precise distributions of decision criteria for all design alternatives in the tradespace is not necessary and appropriate decisions can be made on the basis of imprecise distributions of decision criteria. Key contribution of this study is to investigate an approach using mean-risk analysis to sequentially evaluate a tradespace of design alternatives by bounding and sequentially reducing the imprecision in evaluation of experimental/numerical performance. A sequential decision process is presented where models of increasing fidelity are used to discriminate dominated design alternatives from the tradespace on the basis of imprecise distributions of decision criteria. Application of the framework is demonstrated on a multi-objective discrete choice problem of designing a two bar truss.
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- 2017
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110. Target classification in SAS imagery using orthogonal basis selection
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Andrew M. Wallace, Yan Pailhas, Yvan Petillot, James R. Hopgood, and Puneet S. Chhabra
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Engineering ,Side-scan sonar ,business.industry ,Pattern recognition ,Sparse approximation ,Sonar ,Orthogonal basis ,Set (abstract data type) ,Synthetic aperture sonar ,Computer vision ,Artificial intelligence ,business ,Focus (optics) ,Selection (genetic algorithm) - Abstract
This work proposes an approach that finds efficient representations for training and classification of different mine like objects (MLOs) in underwater imagery, e.g. side scan sonar and synthetic aperture sonar (SAS). The focus is on the design and selection of a compact, optimal and a non linear snbspace, a dictionary, based on the gradient and curvature models in 2D images. Here, the traditional sparse approximation formulation is decoupled and modified by an additional discriminating objective function and a corresponding selection strategy is proposed. During training, using a set of labelled sonar images, a single optimised discriminatory dictionary is learnt which can then be used to represent MLOs. During classification, this dictionary together with optimised coefficient vectors is used to label scene entities. Evaluation of our approach has resulted in classification accuracies of 95% and 94% on realistic synthetic side-scan images and real CMRE SAS imagery, respectively.
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- 2017
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111. Investigation of the Sustainability and Resilience Characteristics of Buildings Including Existing and Potential Assessment Metrics
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Jaskanwal P. S. Chhabra, Vaclav Hasik, Melissa M. Bilec, and Gordon P. Warn
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business.industry ,Sustainability ,Environmental resource management ,Potential assessment ,Business ,Resilience (network) ,Environmental planning - Published
- 2017
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112. MON-121 Does hepcidin level contribute significantly to anemia management in chronic kidney disease patients on heamodialysis? – A cross-sectional study
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N.P. Aggarwal, Amit Gupta, N. Singh, S. Chhabra, T. Sarkar, and L.K. Jha
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medicine.medical_specialty ,biology ,Nephrology ,business.industry ,Cross-sectional study ,Hepcidin ,Internal medicine ,medicine ,biology.protein ,business ,medicine.disease ,Anemia management ,Kidney disease - Published
- 2019
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113. PS1071 PRELIMINARY RESULTS OF A PHASE 1 DOSE ESCALATION STUDY OF THE FIRST-IN-CLASS ANTI-CD74 ANTIBODY DRUG CONJUGATE (ADC), STRO-001, IN PATIENTS WITH ADVANCED B-CELL MALIGNANCIES
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N. Shah, A. Krishnan, J. Burke, J. Melear, A. Spira, L. Popplewell, C. Andreadis, S. Chhabra, J. Sharman, J. Kaufman, J. Cohen, R. Niesvizky, T. Martin, C. DiLea, J. Kuriakose, S. Matheny, and A. Molina
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Antibody-drug conjugate ,medicine.anatomical_structure ,CD74 ,business.industry ,Dose escalation ,medicine ,Cancer research ,In patient ,Hematology ,business ,B cell - Published
- 2019
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114. P021: Interventions to reduce emergency department door-to-ECG times: a systematic review
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J. Perry, D. Eagles, E. Kwok, and S. Chhabra
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business.industry ,Emergency Medicine ,Psychological intervention ,Medicine ,Medical emergency ,Emergency department ,business ,medicine.disease - Abstract
Introduction: We wished to identify emergency department interventions that lead to improvement in door-to-ECG times for adults presenting with symptoms suggestive of acute coronary syndrome (ACS). Methods: Two reviewers searched Medline, Embase, CINAHL and Cochrane CENTRAL from inception to April 2018 for studies in adult emergency departments with an identifiable intervention to reduce median door-to-ECG times when compared to the institution's baseline. Quality was assessed using the ‘Quality Improvement Minimum Quality Criteria Set’ (QI-MQCS) critical appraisal tool. The primary outcome was the absolute median reduction in door-to-ECG times as calculated by the difference between the post-intervention time and pre-intervention time. Results: Two reviewers identified 809 unique articles, yielding 11 before-after quality improvement studies that met eligibility criteria (N = 15,622 patients). The majority of studies (10/11) reported bundled interventions and most (10/11) showed statistical improvement in door-to-ECG times. The most common interventions were: having a dedicated ECG machine and technician in triage (5/11); improved triage education (4/11); improved triage disposition (2/11); and data feedback mechanisms (1/11). Conclusion: There are multiple interventions that show promise for reducing emergency department door-to-ECG times. Effective bundled interventions include having a dedicated ECG technician, triage education and better triage disposition. These changes, bundled together, can help intuitions attain best practice guidelines. Emergency departments must first understand their local context before adopting any single or group of interventions.
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- 2019
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115. Consumers’ Attitudes Toward Functional Foods: A Review.
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A., Bakshi, S., Chhabra, and R., Kaur
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ENRICHED foods , *ANTIOXIDANTS , *CONSUMER attitudes , *DIET , *DIETARY fiber , *MINERALS , *MICRONUTRIENTS , *VITAMINS , *FUNCTIONAL foods - Abstract
The market for functional foods, fortified with added nutrients such as minerals, vitamins, micronutrients, antioxidants and fibers, is on the rise. In this review, we discuss the concept and nature of functional foods, the constituents or ingredients that are commonly used to fortify these foods, and the purpose of fortification. Finally, the review surveys consumers’ attitudes toward functional foods and their importance to help their development and marketing. [ABSTRACT FROM AUTHOR]
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- 2020
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116. Safety of prolonged latency in preterm prelabor rupture of membranes
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S, Chhabra, primary and P, Kalra, additional
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- 2018
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117. Histomorphometry of Umbilical Cord and its Vessels in Pre- Eclampsia as Compared to Normal Pregnancies
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S Chhabra, Manisha Barnwal, SK Rathi, and S Nanda
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medicine.medical_specialty ,Fetus ,Eclampsia ,Formalin fixed paraffin embedded ,Planimeter ,business.industry ,Urology ,medicine.disease ,Umbilical cord ,Umbilical vein ,Surgery ,medicine.anatomical_structure ,Obstetrics and gynaecology ,medicine ,Vein ,business - Abstract
Aims: To study and compare the morphometric alteration in the umbilical cord obtained from thirty normal pregnancies (Group-I) and thirty pre-eclamptic pregnancies (Group-II). Methods: Morphological changes in umbilical cords were examined on formalin fixed paraffin embedded section. Various parameters were measured by planimeter. Results: In pre-eclamptic group total vessel area, total vein area, total luminal area of vein, and wall thickness of arteries were increased, whereas jelly area and wall thickness of vein were decreased as compared to normal group. Conclusion: Increased umbilical arterial thickness, decreased umbilical vein wall thickness and increased luminal area of vein which could be a predictor of intrauterine growth retardation in term pre-eclamptic patients. Nepal Journal of Obstetrics and Gynaecology / Vol 7 / No. 1 / Issue 13 / Jan- June, 2012 / 28-32 DOI: http://dx.doi.org/10.3126/njog.v7i1.8832
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- 2013
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118. Maternal morbidity with early onset hypertensive disorders during pregnancy
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Singh A and S. Chhabra
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Pregnancy ,medicine.medical_specialty ,Placental abruption ,Obstetrics ,business.industry ,Maternal morbidity ,Late onset ,medicine.disease ,Hypertensive retinopathy ,Late Onset Disorders ,medicine ,Gestation ,Maternal death ,business - Abstract
Background: Hypertensive disorders of pregnancy (HDsP) are being divided into early onset (EO), late onset (LO) disorders, depending upon gestation at diagnosis, because of differences in causes, pathology, outcome and sequale. It seems EO HDsP cause much more morbidity in the mother. Objective: To know differences in maternal morbidity EO HDsP compared to late onset disorders. Material Method: Study was done to know complications in cases of 1046 cases of EO LO HDsP, managed over 2 years, 11.73% of 8920 births during the study period. EO cases were (Category A)-20 to
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- 2017
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119. Birth Preparedness and Complications Readiness for Safe Birth, Safe Womanhood and Safe Childhood
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S Chhabra
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medicine.medical_specialty ,Obstetrics ,business.industry ,Family medicine ,Birth preparedness ,medicine ,business - Published
- 2016
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120. Discriminating Underwater LiDAR Target Signatures Using Sparse Multi-Spectral Depth Codes
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Aurora Maccarone, Andrew M. Wallace, Gerald S. Buller, Aongus McCarthy, and Puneet S. Chhabra
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Wavelength ,Geography ,Lidar ,business.industry ,Histogram ,Multispectral image ,Waveform ,Photonics ,Underwater ,business ,Photon counting ,Remote sensing - Abstract
The analysis and discrimination of underwater multi-spectral full-waveform LiDAR signatures acquired using a single-photon counting sensor is presented. We use a realistic scaled exemplar of a marine environment, with known and unknown targets, and show how we can both discriminate different materials and detect and locate mines. Each waveform is a temporal photon histogram whose inherent nature changes with the laser wavelength, target geometry and environment. Discriminatory dictionaries for target materials and mine types are learnt by making multi-spectral measurements. An accuracy of 97.8% and 98.7% was achieved for material and mine type discrimination, respectively.
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- 2016
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121. Practices for Prevention, Therapy of Primary Dysmenorrhoea
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S Chhabra
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medicine.medical_specialty ,business.industry ,Physical therapy ,Medicine ,Primary dysmenorrhoea ,business - Published
- 2016
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122. Primary malignant melanoma of aryepiglottic fold
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R Sen, PK Gupta, H Yadav, A Sharma, P Parmar, and S Chhabra
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Larynx ,Pathology ,medicine.medical_specialty ,business.industry ,Melanoma ,General Medicine ,medicine.disease ,Lesion ,03 medical and health sciences ,Rare tumor ,0302 clinical medicine ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,medicine ,Neoplasm ,medicine.symptom ,030223 otorhinolaryngology ,business ,neoplasms ,Aryepiglottic fold - Abstract
Background : Primary malignant melanoma rarely arises from noncutaneous tissues that contain melanocytes. Head and neck mucosal melanomas account for 0.7% to 3.8% of all melanomas. Here we report a case of primary malignant melanoma of aryepiglottic fold. Result : Here we reported a case of primary malignant melanoma of aryepiglottic fold. Conclusion : Primary aryepiglottic fold melanoma is an exceptionally rare neoplasm with early distant metastases and aggressive fatal course. Early diagnosis and proper line of treatment are crucial for survival. Physicians should keep a high index of suspicion for diagnosis of this rare tumor especially in old age with pigmented or non-pigmented lesion in larynx.
- Published
- 2016
123. α-pinene photooxidation under controlled chemical conditions – Part 1: Gas-phase composition in low- and high-NOx environments
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P. S. Chhabra, Paul O. Wennberg, Katherine A. Schilling, Man Nin Chan, John H. Seinfeld, Nathan C. Eddingsaas, Lindsay D. Yee, and C. L. Loza
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Atmospheric Science ,chemistry.chemical_compound ,Ammonium sulfate ,Pinene ,Chemistry ,Yield (chemistry) ,Inorganic chemistry ,Sulfuric acid ,Composition (visual arts) ,Sulfate ,Chemical composition ,Aerosol - Abstract
The gas-phase oxidation of α-pinene produces a large amount of secondary organic aerosol (SOA) in the atmosphere. A number of carboxylic acids, organosulfates and nitrooxy organosulfates associated with α-pinene have been found in field samples and some are used as tracers of α-pinene oxidation. α-pinene reacts readily with OH and O3 in the atmosphere followed by reactions with both HO2 and NO. Due to the large number of potential reaction pathways, it can be difficult to determine what conditions lead to SOA. To better understand the SOA yield and chemical composition from low- and high-NOx OH oxidation of α-pinene, studies were conducted in the Caltech atmospheric chamber under controlled chemical conditions. Experiments used low O3 concentrations to ensure that OH was the main oxidant and low α-pinene concentrations such that the peroxy radical (RO2) reacted primarily with either HO2 under low-NOx conditions or NO under high-NOx conditions. SOA yield was suppressed under conditions of high-NOx. SOA yield under high-NOx conditions was greater when ammonium sulfate/sulfuric acid seed particles (highly acidic) were present prior to the onset of growth than when ammonium sulfate seed particles (mildly acidic) were present; this dependence was not observed under low-NOx conditions. When aerosol seed particles were introduced after OH oxidation, allowing for later generation species to be exposed to fresh inorganic seed particles, a number of low-NOx products partitioned to the highly acidic aerosol. This indicates that the effect of seed acidity and SOA yield might be under-estimated in traditional experiments where aerosol seed particles are introduced prior to oxidation. We also identify the presence of a number of carboxylic acids that are used as tracer compounds of α-pinene oxidation in the field as well as the formation of organosulfates and nitrooxy organosulfates. A number of the carboxylic acids were observed under all conditions, however, pinic and pinonic acid were only observed under low-NOx conditions. Evidence is provided for particle-phase sulfate esterification of multi-functional alcohols.
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- 2012
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124. Subacute oral and dermal toxicity of tert-butyl hydroperoxide in Fischer F344/N rats and B6C3F1 mice
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Maria B. Kadiiska, Rajendra S. Chhabra, Daphne Vasconcelos, Milton R. Hejtmancik, and Mamta Behl
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Male ,medicine.medical_specialty ,No-observed-adverse-effect level ,Toxicology ,Muscle hypertrophy ,Mice ,Lethargy ,tert-Butylhydroperoxide ,Dermis ,Oral administration ,Internal medicine ,medicine ,Animals ,Skin ,Mouth ,Dose-Response Relationship, Drug ,Epidermis (botany) ,Chemistry ,Electron Spin Resonance Spectroscopy ,General Medicine ,Hyperplasia ,medicine.disease ,Rats, Inbred F344 ,Rats ,medicine.anatomical_structure ,Endocrinology ,Anesthesia ,Toxicity ,Female - Abstract
Tert-butyl hydroperoxide (TBHP) is a catalyst frequently used in oxidation and sulfonation reactions in the plastics industry. Since the toxicological evaluation of TBHP remains unknown, the National Toxicology Program (NTP) designed studies to characterize and compare TBHP toxicity by the dermal and oral (gavage) routes in male and female Fischer 344 rats and B6C3F1 mice in 14-day exposures. Rats and mice were administered TBHP at 22, 44, 88, 176 or 352 mg/kg in 0.5% aqueous methylcellulose for the gavage studies. In the dermal studies, mice were administered the same doses as above, while rats were administered four doses (22, 44, 88, 176 mg/kg) in 50% aqueous acetone. Results from the gavage studies revealed treatment-related decreases in survival in male rats and body weights in both male and female rats in the 352 mg/kg group. Clinical signs included post-treatment lethargy, thinness, abnormal breathing, ruffled fur, and/or ataxia which occurred sporadically. The male mice showed a statistically significant decrease in body weight in the 44, 88, 176, and 352 mg/kg groups. The major target organs of toxicity were the forestomach in male and female rats and mice, and the esophagus in male and female rats and in male mice. In addition, there was an increase in the absolute and relative liver weight in female mice with hepatocellular hypertrophy in the top-dose group only. Results from spin trapping experiments revealed the presence of electron paramagnetic resonance signals from radical adducts in the blood and organic extracts of the liver and kidneys of rats treated by gavage with 176 mg/kg TBHP, suggesting the involvement of free- radical generation. The no observed adverse effect level (NOAEL) was considered to be 22 mg/kg in rats and male mice, and 44 mg/kg in female mice. In the dermal studies, there was no effect on survival, body weight, or organ weights in either rats or mice. TBHP administration at the site of application resulted in dermal irritation, hyperkeratosis, hyperplasia, and/or inflammation of the epidermis and inflammation of the dermis at 176 mg/kg and above in male and female rats. Dermal irritation at the site of application was noted in all the mice exposed to 352 mg/kg TBHP. Histopathological lesions in the epidermis and dermis were seen in the 88-352 mg/kg males and in the 176-352 mg/kg females. The NOAEL was found to be 88 mg/kg for male rats and female mice, and 44 mg/kg for female rats and male mice. In conclusion, these studies demonstrate that TBHP is metabolized to free radicals and is a contact irritant affecting skin by the dermal route of exposure, and forestomach and esophagus by oral administration. There was no evidence of systemic absorption by the dermal route of exposure based on lack of pathological findings (Supported by National Institute of Environmental Health Sciences Contract No. N01-ES-65406).
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- 2012
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125. Comparative dermal toxicity of dicyclohexylcarbodiimide and diisopropylcarbodiimide in rodents
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Mamta Behl, Inok Surh, Rajendra S. Chhabra, and Susan A. Elmore
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Male ,Pathology ,medicine.medical_specialty ,Necrosis ,Cell ,Inflammation ,Pharmacology ,Toxicology ,law.invention ,Mice ,law ,hemic and lymphatic diseases ,medicine ,Animals ,Carcinogen ,Skin ,integumentary system ,Chemistry ,fungi ,General Medicine ,Hyperplasia ,medicine.disease ,Rats, Inbred F344 ,Rats ,Carbodiimides ,medicine.anatomical_structure ,Dicyclohexylcarbodiimide ,Toxicity ,Recombinant DNA ,Female ,Animal studies ,medicine.symptom ,circulatory and respiratory physiology - Abstract
Dicyclohexylcarbodiimide (DCC) and Diisopropylcarbodiimide (DIC) are two representative chemicals in the carbodiimide class of chemicals used in industry as stabilizing agents. There is a potential of dermal exposure to these agents in chemical, pharmaceutical and recombinant DNA industries. The National Toxicology Program conducted a number of animal studies to characterize toxicity and carcinogenicity of DIC and DCC. Dermal administration of DCC and DIC in F344/N rats and B6C3F1 mice for 90-days induced skin irritation at the site of application in a dose-dependent manner. Microscopically, dose-dependent increases in epidermal hyperplasia and chronic inflammation were observed. We further evaluated the effects of dermal exposure of DCC and DIC in p53 haploinsufficient and Tg.AC mouse models. Results revealed the skin as the primary target of DCC and DIC exposure as indicated by dose - dependent skin lesions (hyperplasia, inflammation and necrosis). DCC induced squamous cell papillomas in Tg.AC mice but did not induce any neoplastic lesions in p53 haploinsufficient mice. Dermal application of DIC did not induce any neoplastic lesions in Tg.AC mice and p53 haploinsufficient mice. Based on these studies, it was predicted that DIC would be negative and DCC positive for carcinogenic activity in the traditional two-year bioassay. In the subsequent studies, the carcinogenic potential of DIC only in F344 rats and B6C3F1 mice in a traditional 2-year chronic carcinogenicity bioassay was evaluated by the dermal route. Findings revealed the skin as the major target organ of toxicity in both sexes in rats and in male mice. There were no neoplastic lesions observed in rats or mice with the administration of DIC. In rats, there were clinical signs of toxicity in the highest dose-group which included ataxia, excitability, impaired gait, low muscle tone, abnormal breathing, lethargy, and seizures. This was accompanied by non-neoplastic lesions in the brain and lung only at the highest dose level. In conclusion, both DIC and DCC are dermal toxicants. DIC did not have any carcinogenic activity in transgenic mouse models or in the traditional NTP two-year carcinogenicity studies in F344 rats and B6C3F1 mice. DCC was positive in the Tg.AC mouse model and likely to be carcinogenic in the 2-year bioassay as well.
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- 2011
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126. Liver toxicity and carcinogenicity in F344/N rats and B6C3F1 mice exposed to Kava Kava
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Abraham Nyska, Po C. Chan, Barney Sparrow, Milton R. Hejtmancik, Gregory S. Travlos, Rajendra S. Chhabra, Laurene M. Fomby, and Mamta Behl
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Male ,Carcinogenicity Tests ,Mice, Inbred Strains ,Pharmacology ,Toxicology ,Article ,Drug Administration Schedule ,Muscle hypertrophy ,Mice ,Carcinoma ,medicine ,Animals ,Carcinogen ,Kava ,Sex Characteristics ,Dose-Response Relationship, Drug ,business.industry ,General Medicine ,Hepatocellular adenoma ,medicine.disease ,Rats, Inbred F344 ,Rats ,Dose–response relationship ,Liver ,Toxicity ,Female ,Chemical and Drug Induced Liver Injury ,business ,Corn oil ,Food Science - Abstract
Kava Kava is an herbal supplement used as an alternative to antianxiety drugs. Although some reports suggest an association of Kava Kava with hepatotoxicity , it continues to be used in the United States due to lack of toxicity characterization. In these studies F344/N rats and B6C3F1 mice were administered Kava Kava extract orally by gavage in corn oil for two weeks, thirteen weeks or two years. Results from prechronic studies administered Kava Kava at 0.125- to 2g/kg body weight revealed dose-related increases in liver weights and incidences of hepatocellular hypertrophy. In the chronic studies, there were dose-related increases in the incidences of hepatocellular hypertrophy in rats and mice administered Kava Kava for up to 1 g/kg body weight. This was accompanied by significant increases in incidences of centrilobular fatty change. There was no treatment- related increase in carcinogenic activity in the livers of male or female rats in the chronic studies. Male mice showed a significant dose-related increase in the incidence of hepatoblastomas. In female mice, there was a significant increase in the combined incidence of hepatocellular adenoma and carcinoma in the low and mid dose groups but not in the high dose group. These findings were accompanied by several nonneoplastic hepatic lesions.
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- 2011
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127. Need for relooking into management of eclampsia
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A Kakani, S Chhabra, and D Goyal
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Microbiology (medical) ,medicine.medical_specialty ,lcsh:Arctic medicine. Tropical medicine ,Conservative management ,lcsh:RC955-962 ,Maternal-fetoneonatal outcome ,lcsh:Medicine ,Perinatal outcome ,Baby ,Pregnancy ,Convulsion ,medicine ,Eclampsia ,Obstetrics ,business.industry ,Incidence (epidemiology) ,fungi ,lcsh:R ,medicine.disease ,Infectious Diseases ,Gestation ,medicine.symptom ,business ,Delivery - Abstract
Objective: To explore the incidence, types, profiles, gestation, therapies, maternal-fetoneonatal outcomes with special reference to conservative eclampsia management in preterm cases with live baby. Methods: A critical analysis of eclampsia cases over two decades was performed to explore outcomes with different therapies. Results: Of 64 014 deliveries, 416 cases of eclampsia were managed, giving an incidence of 0.65% of births with decreasing trends (0.79% in Block A and 0.56% in Block E). 132 (31.73%) had lytic cocktail, (58.69% in Block A and 2.66% in Block E), 76 (18.27%) had magnesium sulphate (MgSO4) and pethidine or diazepam (30.43% in Block A and 5.33% in Block E), 208 (50.00%) received MgSO4 and nifedipine (10.86% in Block A and 92.00% in Block E). Mean induction delivery interval with lytic cocktail was 23.2 hours (shortest), and MgSO4 with sedatives, 48 hours, and MgSO4 with nifedipine, 72 hours (longest). In 33 cases, induction could be postponed if babies were live, preterm and mothers ’ convulsions could be controlled. Lytic cocktail perinatal mortality rate (PMR) was 765.15. PMR of MgSO4 with sedatives was 500. PMR of MgSO4 with nifedipine was 346. Conclusions: Though some babies died in utero, in carefully selected cases with close supervision, pregnancy may be continued with eclampsia to increase fetal maturity without risk to mother, in settings where resources are scarce for very very low birth weight babies. Conservative management improves perinatal outcome but a careful balance of maternal wellbeing is essential.
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- 2011
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128. Elemental composition and oxidation of chamber organic aerosol
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John H. Seinfeld, Manjula R. Canagaratna, D. R. Worsnop, P. S. Chhabra, Lynn M. Russell, Nga L. Ng, Richard C. Flagan, and A. L. Corrigan
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Atmospheric Science ,Ozonolysis ,Hydrogen ,Chemistry ,Analytical chemistry ,Ternary plot ,chemistry.chemical_element ,Mass spectrometry ,lcsh:QC1-999 ,Spectral line ,Aerosol ,lcsh:Chemistry ,lcsh:QD1-999 ,Elemental analysis ,Van Krevelen diagram ,lcsh:Physics - Abstract
Recently, graphical representations of aerosol mass spectrometer (AMS) spectra and elemental composition have been developed to explain the oxidative and aging processes of secondary organic aerosol (SOA). It has been shown previously that oxygenated organic aerosol (OOA) components from ambient and laboratory data fall within a triangular region in the f44 vs. f43 space, where f44 and f43 are the ratios of the organic signal at m/z 44 and 43 to the total organic signal in AMS spectra, respectively; we refer to this graphical representation as the "triangle plot." Alternatively, the Van Krevelen diagram has been used to describe the evolution of functional groups in SOA. In this study we investigate the variability of SOA formed in chamber experiments from twelve different precursors in both "triangle plot" and Van Krevelen domains. Spectral and elemental data from the high-resolution Aerodyne aerosol mass spectrometer are compared to offline species identification analysis and FTIR filter analysis to better understand the changes in functional and elemental composition inherent in SOA formation and aging. We find that SOA formed under high- and low-NOx conditions occupy similar areas in the "triangle plot" and Van Krevelen diagram and that SOA generated from already oxidized precursors allows for the exploration of areas higher on the "triangle plot" not easily accessible with non-oxidized precursors. As SOA ages, it migrates toward the top of the triangle along a path largely dependent on the precursor identity, which suggests increasing organic acid content and decreasing mass spectral variability. The most oxidized SOA come from the photooxidation of methoxyphenol precursors which yielded SOA O/C ratios near unity. α-pinene ozonolysis and naphthalene photooxidation SOA systems have had the highest degree of mass closure in previous chemical characterization studies and also show the best agreement between AMS elemental composition measurements and elemental composition of identified species within the uncertainty of the AMS elemental analysis. In general, compared to their respective unsaturated SOA precursors, the elemental composition of chamber SOA follows a slope shallower than −1 on the Van Krevelen diagram, which is indicative of oxidation of the precursor without substantial losss of hydrogen, likely due to the unsaturated nature of the precursors. From the spectra of SOA studied here, we are able to reproduce the triangular region originally constructed with ambient OOA compents with chamber aerosol showing that SOA becomes more chemically similar as it ages. Ambient data in the middle of the triangle represent the ensemble average of many different SOA precursors, ages, and oxidative processes.
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- 2011
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129. Vitex agnus castus - an overview
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Gurmeet S. Chhabra and Kala S. Kulkarni
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vitex agnus castus, pharmacology, chemistry, clinical applications ,lcsh:RZ409.7-999 ,lcsh:Miscellaneous systems and treatments - Abstract
Vitex agnus castus was already in ancient medicinal art as an official medicinal plant and is named in the work of Hippocrates, Dioskurides, Theophrastus and others. This review attempts to encompass the available literature on Vitex agnus castus with respect to its pharmacognostic characters, traditional uses, chemical constituents and summary of various pharmacological activities and clinical effects. Other aspects such as toxicology and precautions are also discussed.
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- 2011
130. A review of alternatives to di (2-ethylhexyl) phthalate-containing medical devices in the neonatal intensive care unit
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J S Chhabra, E M Reitano, Robin M. Whyatt, E D S Van Vliet, and G P Bergen
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endocrine system ,medicine.medical_specialty ,Neonatal intensive care unit ,Polyurethanes ,Silicones ,Benzoates ,chemistry.chemical_compound ,Plasticizers ,Diethylhexyl Phthalate ,Intensive Care Units, Neonatal ,Humans ,Maternal fetal ,Medicine ,Neonatology ,Intensive care medicine ,Equipment and Supplies, Hospital ,Equipment Safety ,Extramural ,business.industry ,organic chemicals ,Phthalate ,Obstetrics and Gynecology ,Equipment Design ,chemistry ,Polyethylene ,Pediatrics, Perinatology and Child Health ,Safety Equipment ,business - Abstract
To conduct an extensive literature and toxicological database review on substitute compounds and available alternative medical products to replace polyvinyl chloride (PVC) and/or di(2-ethylhexyl) phthalate (DEHP), and conduct a DEHP-medical inventory analysis at a large metropolitan neonatal intensive care unit (NICU).A systematic search for DEHP-free alternative products was performed using online databases. An informal audit of a large metropolitan NICU was undertaken in 2005 and 2006; 21 products were identified that could potentially contain DEHP. Availability of DEHP-free alternatives was determined through company websites and phone interviews.Two alternative approaches are available for replacing DEHP in NICU medical products: (1) replacement by DEHP-free plasticizers; and (2) replacement of PVC entirely through the use of other polymers. Both approaches seem to provide less harmful substitutes to DEHP, but support PVC-free polymers as the preferred alternative. However, significant data gaps exist, particularly for the alternative polymers. In all, 10 out of 21 (48%) products in the NICU audit were DEHP-free; six consisted of alternative polymers and four of alternative plasticizers. Of the remaining 11 products, only three were available without DEHP at the time of the audit.Because of significant data gaps, systematic toxicological testing of DEHP-free alternatives is imperative. Continued development of alternative products is also needed.
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- 2011
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131. Changing world, changing trusts and health providers' sufferings
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S. Chhabra
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Health personnel ,Nursing ,Workplace violence ,Perception ,media_common.quotation_subject ,Workforce ,Liability ,General Medicine ,Cochrane Library ,Psychology ,Healthcare providers ,media_common ,Variety (cybernetics) - Abstract
Workplace violence (WPV) is a serious problem anywhere, but is one of the most complex issues in health settings. Many factors contribute to WPV is health setting, health workers functioning in stressful environment, 24-h access to many, presence of drugs, and human sufferings with limitations in care. Violence may take a variety of forms, verbal aggression to physical assault, use of deadly weapons against physicians, others, and even patients. It is, therefore, associated with a variety of risks to workers safety, as well as organizational liability. The objective was to know happenings and challenges in the prevention of violence against health providers. This simple review of available studies and opinions was done by using Uptodate, ERMED CONSORTIUM, Cochrane Library, Delnet, and MedIND, and self-experiences were added. Physical violence (PV) against doctors and other health personnel is increasingly being reported. It is believed that more than 75% of doctors face violence during their practice. Almost half of the violent incidents occur in critical care units. WPV has been categorized into physical and mental, but all types of violence are destructive, in one or other way. There is evidence that female health workers are exposed to PV more often than others. It is essential to identify risk factors in order to prevent and manage WPV against health providers. Reasons for violent outbursts include inadequate workforce, infrastructure to treat patient load, and long waiting times. Many health personnel never report exposure of violence to anyone because of various reasons including perception that reporting was useless. Though it is difficult to completely eliminate violence in health-care settings, and although there is no “one-size-fits-all” approach for prevention, there are many ways to reduce the potential for violent occurrences and to minimize the impact if violence does occur.
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- 2019
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132. Recovery of Ocular Motor Cranial Nerve Palsy After Herpes Zoster Ophthalmicus
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Karl C. Golnik and Manpreet S. Chhabra
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Adult ,Male ,Pediatrics ,medicine.medical_specialty ,Time Factors ,genetic structures ,Ocular motor ,Cranial nerve palsy ,Oculomotor Nerve ,Chart review ,Oculomotor Nerve Diseases ,medicine ,Humans ,Aged ,Retrospective Studies ,Aged, 80 and over ,business.industry ,Follow up studies ,virus diseases ,Retrospective cohort study ,Recovery of Function ,Middle Aged ,eye diseases ,Ophthalmology ,Herpes Zoster Ophthalmicus ,Female ,Neurology (clinical) ,business ,Follow-Up Studies - Abstract
To report the course of ocular motor cranial nerve palsy due to herpes zoster.A retrospective chart review identified patients with ocular motor cranial nerve palsy occurring at the time of herpes zoster ophthalmicus. Patients were seen by a single neuro-ophthalmologist from 1994 to 2012.Twenty-one patients were identified; 3 were excluded because of incomplete follow-up. Nine (50%) had complete recovery and 8 (44%) had partial recovery but no diplopia in primary gaze (mean time = 10 weeks). One patient with complete ophthalmoplegia had persistent diplopia in primary position for recovery.Ophthalmoplegia secondary to herpes zoster ophthalmicus has good long-term prognosis for recovery.
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- 2014
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133. Diagnostic criteria of traumatic central cord syndrome. Part 2: A Questionnaire Survey among Spine Specialists
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J J, van Middendorp, M H, Pouw, K C, Hayes, R, Williams, H S, Chhabra, C, Putz, R P H, Veth, A C H, Geurts, S, Aito, J, Kriz, W, McKinley, F W A, van Asbeck, A, Curt, M G, Fehlings, H, Van de Meent, A J F, Hosman, J, Benito, and University of Zurich
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medicine.medical_specialty ,610 Medicine & health ,Central Cord Syndrome ,Diagnosis, Differential ,Central nervous system disease ,Disability Evaluation ,Surveys and Questionnaires ,medicine ,Humans ,Paralysis ,Spinal cord injury ,Rachis ,Human Movement & Fatigue [NCEBP 10] ,Muscle Weakness ,Spinal Cord Trauma ,business.industry ,Data Collection ,Questionnaire ,General Medicine ,medicine.disease ,Central cord syndrome ,2728 Neurology (clinical) ,Vertebral canal ,Neurology ,2808 Neurology ,Physical therapy ,10046 Balgrist University Hospital, Swiss Spinal Cord Injury Center ,Neurology (clinical) ,medicine.symptom ,business - Abstract
Item does not contain fulltext STUDY DESIGN: A questionnaire survey. OBJECTIVES: To evaluate the need for the introduction of quantitative diagnostic criteria for the traumatic central cord syndrome (TCCS). SETTING: An online questionnaire survey with participants from all over the world. METHODS: An invitation to participate in an eight-item online survey questionnaire was sent to surgeon members of AOSpine International. RESULTS: Out of 3340 invited professionals, 157 surgeons (5%) from 41 countries completed the survey. Whereas most of the respondents (75%) described greater impairment of the upper extremities than of the lower extremities in their own TCCS definitions, symptoms such as sensory deficit (39%) and bladder dysfunctions (24%) were reported less frequently. Initially, any difference in motor strength between the upper and lower extremities was considered most frequently (23%) as a 'disproportionate' difference in power. However, after presenting literature review findings, the majority of surgeons (61%) considered a proposed difference of at least 10 points of power (based on the Medical Research Council scale) in favor of the lower extremities as an acceptable cutoff criterion for a diagnosis of TCCS. Most of the participants (40%) felt that applying a single criterion to the diagnosis of TCCS is insufficient for research purposes. CONCLUSION: Various definitions of TCCS were used by physicians involved in the spinal trauma care. The authors consider a difference of at least 10 motor score points between upper and lower extremity power a clear diagnostic criterion. For clinical research purposes, this diagnostic criterion can be considered as a face valid addendum to the commonly applied TCCS definition as introduced by Schneider et al. 01 september 2010
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- 2010
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134. A rare case of a retroperitoneal cystic lymphangioma
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Raunaq S. Chhabra, Deepali H. Janugade, Aniket Surushe, and Hemant B. Janugade
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body regions ,medicine.medical_specialty ,business.industry ,Rare case ,Lymphangioma ,medicine ,Retroperitoneal cystic lymphangioma ,Surgical excision ,Radiology ,Retroperitoneal cyst ,medicine.disease ,business - Abstract
Retroperitoneal Lymphangiomas are rare and account for only 1% of lymphangiomas. They usually present in infancy, rarely they may present symptomatically in adulthood. We present a case of a 19-year old female with a symptomatic retroperitoneal lymphangioma. It was treated with complete surgical excision. Retroperitoneal lymphangiomas are rare. Imaging alone cannot differentiate them from other retroperitoneal cystic masses. Surgical excision is the treatment of choice and required for final diagnosis.
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- 2018
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135. Safety of magnetic resonance imaging of deep brain stimulator systems: a serial imaging and clinical retrospective study
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Edward K. Sung, Roy A.E. Bakay, Aviva Abosch, Vaninder S Chhabra, Robert E. Gross, and Klaus Mewes
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Dystonia ,medicine.medical_specialty ,Deep brain stimulation ,medicine.diagnostic_test ,business.industry ,medicine.medical_treatment ,Retrospective cohort study ,Magnetic resonance imaging ,General Medicine ,medicine.disease ,Deep brain stimulator ,Imaging phantom ,Serial imaging ,medicine ,In patient ,Radiology ,business - Abstract
Object With the expanding indications and increasing number of patients undergoing deep brain stimulation (DBS), postoperative MR imaging is becoming even more important in guiding clinical care and practice-based learning; important safety concerns have recently emerged, however. Although phantom model studies have driven conservative recommendations regarding imaging parameters, highlighted by 2 recent reports describing adverse neurological events associated with MR imaging in patients with implanted DBS systems, the risks of MR imaging in such patients in clinical practice has not been well addressed. In this study, the authors capitalized on their large experience with serial MR imaging (3 times per patient) to use MR imaging itself and clinical outcomes to examine the safety of MR imaging in patients who underwent staged implantation of DBS electrodes for Parkinson disease, tremor, and dystonia. Methods Sixty-four patients underwent staged bilateral lead implantations between 1997 and 2006, and each patient underwent 3 separate MR imaging sessions subsequent to DBS placement. The first of these was performed after the first DBS placement, the second occurred prior to the second DBS placement, and third was after the second DBS placement. Follow-up was conducted to examine adverse events related either to MR imaging or to DBS-induced injury. Results One hundred and ninety-two MR images were obtained, and the mean follow-up time was 3.67 years. The average time between the first and second, and second and third MR imaging sessions was 19.4 months and 14.7 hours, respectively. Twenty-two MR imaging–detected new findings of hemorrhage were documented. However, all new findings were related to acute DBS insertion, whereas there were no new findings after imaging of the chronically implanted electrode. Conclusions Although potential risks of MR imaging in patients undergoing DBS may be linked to excessive heating, induced electrical currents, disruption of the normal operation of the device, and/or magnetic field interactions, MR imaging can be performed safely in these patients and provides useful information on DBS lead location to inform patient-specific programming and practice-based learning.
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- 2010
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136. Role of myofibroblasts and collagen type IV in patients of IgA nephropathy as markers of renal dysfunction
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RW Minz, A Bakshi, S Chhabra, K Joshi, and V Sakhuja
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Creatinine ,Pathology ,medicine.medical_specialty ,biology ,business.industry ,myofibroblasts ,Renal function ,Collagen type IV ,IgA nephropathy ,medicine.disease ,Nephropathy ,chemistry.chemical_compound ,chemistry ,Nephrology ,Fibrosis ,biology.protein ,Medicine ,Immunohistochemistry ,Original Article ,Antibody ,business ,Myofibroblast ,Grading (tumors) - Abstract
The aim was to evaluate the role of a-smooth muscle actin (SMA) and collagen type IV as markers of chronicity in renal biopsies of IgA nephropathy patients and to correlate the degree of their interstitial expression with renal function as judged by serum creatinine. Renal biopsies from 29 clinically, histologically and immunologically confirmed cases of IgA nephropathy were reviewed to assess activity and chronicity indices. Immunohistochemical stains for alpha-SMA and collagen type IV was performed on 23 patients with adequate tissue available in the block. The interstitial expression of alpha-SMA and collagen type IV was then correlated with chronicity and activity indices, serum creatinine and 24 hours urinary protein. Pearson's coefficient of correlation, unpaired-t test were used for statistical analysis. alpha-SMA and collagen type IV were shown to be expressed in the interstitium in all 22 cases showing interstitital fibrosis. Both showed a similar distribution pattern with predominant periglomerular and peritubular positivity. The cases were divided into two groups (low and high grade) depending on the percentage of interstitial area showing positivity for these two antibodies. On statistical analysis, the expression of both a-smooth muscle actin and collagen type IV showed a striking correlation with the histological chronicity index (P0.01). A positive correlation was also noted with the serum creatinine at the time of diagnosis. It is seen that an immunohistochemical approach to grading interstitial fibrosis as in this study is far simpler than the histological grading systems prevalent and is an important baseline prognostic indicator.
- Published
- 2010
137. Toxicity and carcinogenicity studies of methylene blue trihydrate in F344N rats and B6C3F1 mice
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Charles D. Hébert, Douglas W. Bristol, Rajendra S. Chhabra, John C. Peckham, Scott S. Auerbach, and Gregory S. Travlos
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Male ,medicine.medical_specialty ,Adenoma ,Carcinogenicity Tests ,Mice, Inbred Strains ,Kaplan-Meier Estimate ,Toxicology ,Mice ,Species Specificity ,Neoplasms ,Internal medicine ,Carcinoma ,Animals ,Medicine ,Neoplastic transformation ,Lung ,Chronic toxicity ,Sex Characteristics ,Hyperplasia ,Dose-Response Relationship, Drug ,business.industry ,Body Weight ,Mammary Neoplasms, Experimental ,General Medicine ,Hematopoietic Stem Cells ,medicine.disease ,Survival Analysis ,Rats, Inbred F344 ,Small intestine ,Blood Cell Count ,Rats ,Pancreatic islet cell adenoma ,Methylene Blue ,Dose–response relationship ,Endocrinology ,medicine.anatomical_structure ,Toxicity ,Carcinogens ,Female ,business ,Food Science - Abstract
Methylene blue trihydrate has a variety of biomedical and biologically therapeutic applications. Groups of 50 male and 50 female rats and mice were administered methylene blue trihydrate in 0.5% aqueous methylcellulose solution by gavage at doses of 0, 5, 25, or 50mg/kg bw/day (rats) or 0, 2.5, 12.5, and 25mg/kg bw/day (mice), 5 days per week for 2 years. In rats survival of all dosed groups was similar to that of the vehicle controls, whereas mice exhibited a dose-dependent increase in survival. Rats receiving 25 and 50mg/kg bw/day and mice receiving 25mg/kg bw/day developed mild anemia. The incidences of pancreatic islet cell adenoma and adenoma or carcinoma (combined) were increased in all dosed groups of male rats, but increases were statistically significant in 25mg/kg bw/day males only and the dose-response was non-linear. There was a corresponding increase in the incidence of pancreatic islet cell hyperplasia but statistically significant only in the 50mg/kg bw/day male rats. There were no significant increases in neoplastic transformation observed in the mice; however, positive trends were noted for adenoma or carcinoma (combined) of the small intestine and malignant lymphoma.
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- 2010
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138. Glyoxal uptake on ammonium sulphate seed aerosol: reaction products and reversibility of uptake under dark and irradiated conditions
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Richard C. Flagan, John H. Seinfeld, Frank N. Keutsch, Melissa M. Galloway, Arthur W. H. Chan, P. S. Chhabra, and Jason D. Surratt
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Atmospheric Science ,Inorganic chemistry ,respiratory system ,Photochemistry ,complex mixtures ,Oligomer ,lcsh:QC1-999 ,Aerosol ,lcsh:Chemistry ,chemistry.chemical_compound ,Monomer ,chemistry ,lcsh:QD1-999 ,Glyoxal ,Ammonium ,Glycolic acid ,Isoprene ,lcsh:Physics ,Organosulfate - Abstract
Chamber studies of glyoxal uptake onto ammonium sulphate aerosol were performed under dark and irradiated conditions to gain further insight into processes controlling glyoxal uptake onto ambient aerosol. Organic fragments from glyoxal dimers and trimers were observed within the aerosol under dark and irradiated conditions. Glyoxal monomers and oligomers were the dominant organic compounds formed under the conditions of this study; glyoxal oligomer formation and overall organic growth were found to be reversible under dark conditions. Analysis of high-resolution time-of-flight aerosol mass spectra provides evidence for irreversible formation of carbon-nitrogen (C-N) compounds in the aerosol. We have identified 1H-imidazole-2-carboxaldehyde as one C-N product. To the authors' knowledge, this is the first time C-N compounds resulting from condensed phase reactions with ammonium sulphate seed have been detected in aerosol. Organosulphates were not detected under dark conditions. However, active photochemistry was found to occur within aerosol during irradiated experiments. Carboxylic acids and organic esters were identified within the aerosol. An organosulphate, which had been previously assigned as glyoxal sulphate in ambient samples and chamber studies of isoprene oxidation, was observed only in the irradiated experiments. Comparison with a laboratory synthesized standard and chemical considerations strongly suggest that this organosulphate is glycolic acid sulphate, an isomer of the previously proposed glyoxal sulphate. Our study shows that reversibility of glyoxal uptake should be taken into account in SOA models and also demonstrates the need for further investigation of C-N compound formation and photochemical processes, in particular organosulphate formation.
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- 2009
139. Photooxidation of 2-Methyl-3-Buten-2-ol (MBO) as a Potential Source of Secondary Organic Aerosol
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Richard C. Flagan, Frank N. Keutsch, John H. Seinfeld, Paul O. Wennberg, Allan J. Kwan, Arthur W. H. Chan, Melissa M. Galloway, and P. S. Chhabra
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Ammonium sulfate ,Light ,Acetaldehyde ,Nitric Oxide ,Trees ,chemistry.chemical_compound ,Hemiterpenes ,Pentanols ,Pentanes ,Butadienes ,Environmental Chemistry ,Organic chemistry ,Organic Chemicals ,Particle Size ,Sulfate ,NOx ,Aerosols ,chemistry.chemical_classification ,Air Pollutants ,Glycolaldehyde ,Aqueous solution ,Glyoxal ,General Chemistry ,Oxygen ,Hydrocarbon ,chemistry ,Yield (chemistry) ,Gases ,Volatilization ,Environmental Monitoring - Abstract
2-Methyl-3-buten-2-ol (MBO) is an important biogenic hydrocarbon emitted in large quantities by pine forests. Atmospheric photooxidation of MBO is known to lead to oxygenated compounds, such as glycolaldehyde, which is the precursor to glyoxal. Recent studies have shown that the reactive uptake of glyoxal onto aqueous particles can lead to formation of secondary organic aerosol (SOA). In this work, MBO photooxidation under high- and low-NO(x) conditions was performed in dual laboratory chambers to quantify the yield of glyoxal and investigate the potential for SOA formation. The yields of glycolaldehyde and 2-hydroxy-2-methylpropanal (HMPR), fragmentation products of MBO photooxidation, were observed to be lower at lower NO(x) concentrations. Overall, the glyoxal yield from MBO photooxidation was 25% under high-NO(x) and 4% under low-NO(x) conditions. In the presence of wet ammonium sulfate seed and under high-NO(x) conditions, glyoxal uptake and SOA formation were not observed conclusively, due to relatively low (30 ppb) glyoxal concentrations. Slight aerosol formation was observed under low-NO(x) and dry conditions, with aerosol mass yields on the order of 0.1%. The small amount of SOA was not related to glyoxal uptake, but is likely a result of reactions similar to those that generate isoprene SOA under low-NO(x) conditions. The difference in aerosol yields between MBO and isoprene photooxidation under low-NO(x) conditions is consistent with the difference in vapor pressures between triols (from MBO) and tetrols (from isoprene). Despite its structural similarity to isoprene, photooxidation of MBO is not expected to make a significant contribution to SOA formation.
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- 2009
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140. Persistence of fruitless caesarean sections in Indian rural women
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S. Chhabra, S. Raman, and A. Jaiswal
- Subjects
Rural Population ,medicine.medical_specialty ,medicine.medical_treatment ,India ,Pregnancy ,Infant Mortality ,medicine ,Humans ,Caesarean section ,Perinatal Mortality ,reproductive and urinary physiology ,Retrospective Studies ,Health consequences ,Cesarean Section ,Perinatal mortality ,Obstetrics ,business.industry ,Infant, Newborn ,Obstetrics and Gynecology ,Surgical procedures ,medicine.disease ,female genital diseases and pregnancy complications ,surgical procedures, operative ,Fetal Mortality ,Female ,fruitless ,Rural area ,Rural women ,business - Abstract
Caesarean section is one of the commonest major surgical procedures in public and private hospitals. The worldwide rise in the caesarean section rate during the last 50 years is cause for alarm and a matter of concern. This increase deserves international attention not only because of health consequences, resource administration and policies, but also because high caesarean section rates are not associated with low perinatal mortality rates. The present study is an analysis of indications of caesarean sections performed with no take-home baby ('fruitless' caesarean section) between April 1983 and March 2007. It was revealed that the caesarean section rate has increased from 15.47% of births in 1983 to 37.96% births in 2007, and 03.75% of these were fruitless. The overall perinatal mortality rate has reduced from 91.56 in 1983 to 51.20 in 2007, for various reasons. This analysis reveals a large increase in caesarean sections with many being fruitless. While the major causes of perinatal mortality were sepsis, prematurity and congenital anomalies which need to be addressed, it is also essential to review the indications of caesarean section, so as to prevent fruitless caesarean sections.
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- 2009
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141. TRAIL Agonists on Clinical Trials for Cancer Therapy: The Promises and the Challenges
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Vaninder S Chhabra, Chunhai Hao, Anita C. Bellail, Patrick Mulligan, and Ling Qi
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medicine.drug_class ,Apoptosis ,Pharmacology ,Monoclonal antibody ,TNF-Related Apoptosis-Inducing Ligand ,Clinical Trials, Phase II as Topic ,Immune system ,Monitoring, Immunologic ,Neoplasms ,Animals ,Humans ,Medicine ,Clinical Trials as Topic ,Clinical Trials, Phase I as Topic ,biology ,business.industry ,Antibodies, Monoclonal ,Cancer ,General Medicine ,medicine.disease ,Recombinant Proteins ,Clinical trial ,Receptors, TNF-Related Apoptosis-Inducing Ligand ,Monoclonal ,Cancer cell ,biology.protein ,Tumor necrosis factor alpha ,Cisplatin ,Antibody ,business - Abstract
Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is normally expressed in the human immune system and plays a critical role in antitumor immunity. TRAIL interacts with the death receptors, DR4 and DR5, and activates intracellular apoptotic pathway in cancer cells. This discovery has resulted in a rapid development of cancer therapeutic agents that can activate this apoptotic pathway. These therapeutic agents include recombinant human TRAIL (rhTRAIL) and its agonistic monoclonal antibody (MAb) against DR4 and DR5. Phase I trials have established the safety and tolerability of these TRAIL agonists in patients. Phase II trials are currently evaluating the therapeutic efficacy of TRAIL agonists as single agents or in combination with established cancer therapeutics. This review outlines the advances and the challenges in the development of these TRAIL agonists as effective clinical cancer therapeutics.
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- 2009
- Full Text
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142. Possibilities of Planned Small Families in Communities with Lack of Awareness and Scarce Resources
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S, Chhabra, primary
- Published
- 2018
- Full Text
- View/download PDF
143. Secondary organic aerosol (SOA) formation from reaction of isoprene with nitrate radicals (NO3)
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Paul O. Wennberg, Havala O. T. Pye, Richard C. Flagan, P. S. Chhabra, Jason D. Surratt, John D. Crounse, A. J. Kwan, Arthur W. H. Chan, Armin Sorooshian, Nga L. Ng, and John H. Seinfeld
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chemistry.chemical_classification ,Atmospheric Science ,Radical ,Photochemistry ,Aerosol ,Atmosphere ,Troposphere ,chemistry.chemical_compound ,Hydrocarbon ,chemistry ,Volume (thermodynamics) ,Nitrate ,Environmental chemistry ,Isoprene - Abstract
Secondary organic aerosol (SOA) formation from the reaction of isoprene with nitrate radicals (NO3) is investigated in the Caltech indoor chambers. Experiments are performed in the dark and under dry conditions (RH<10%) using N2O5 as a source of NO3 radicals. For an initial isoprene concentration of 18.4 to 101.6 ppb, the SOA yield (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted) ranges from 4.3% to 23.8%. By examining the time evolutions of gas-phase intermediate products and aerosol volume in real time, we are able to constrain the chemistry that leads to the formation of low-volatility products. Although the formation of ROOR from the reaction of two peroxy radicals (RO2) has generally been considered as a minor channel, based on the gas-phase and aerosol-phase data it appears that RO2+RO2 reaction (self reaction or cross-reaction) in the gas phase yielding ROOR products is a dominant SOA formation pathway. A wide array of organic nitrates and peroxides are identified in the aerosol formed and mechanisms for SOA formation are proposed. Using a uniform SOA yield of 10% (corresponding to Mo≅10 μg m−3), it is estimated that ~2 to 3 Tg yr−1 of SOA results from isoprene+NO3. The extent to which the results from this study can be applied to conditions in the atmosphere depends on the fate of peroxy radicals in the nighttime troposphere.
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- 2008
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144. Eye Manifestations of Intrauterine Infections and Their Impact on Childhood Blindness
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Marilyn B. Mets and Manpreet S Chhabra
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Adult ,Pediatrics ,medicine.medical_specialty ,viruses ,Eye disease ,Eye Infections ,Congenital cytomegalovirus infection ,medicine.disease_cause ,Lymphocytic choriomeningitis ,Rubella ,Toxoplasmosis, Congenital ,Herpesviridae ,Chickenpox ,Pregnancy ,medicine ,Humans ,Pregnancy Complications, Infectious ,biology ,business.industry ,Infant, Newborn ,Childhood blindness ,Herpes Simplex ,medicine.disease ,biology.organism_classification ,Toxoplasmosis ,Ophthalmology ,Flavivirus ,Cytomegalovirus Infections ,Immunology ,Female ,business - Abstract
Intrauterine infections are important causes of childhood blindness in both developed and developing countries. Chorioretinal scars are the most characteristic eye manifestation of a congenital or prenatal infection. The various ocular manifestations of congenital infections, summarized by the mnemonic TORCH, and recent additions to the "other" category (lymphocytic choriomeningitis virus and West Nile virus) are discussed.
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- 2008
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145. Toxicity and carcinogenicity of methyl isobutyl ketone in F344N rats and B6C3F1 mice following 2-year inhalation exposure
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John R. Bucher, Ronald A. Herbert, Matthew D. Stout, Rajendra S. Chhabra, Joseph H. Roycroft, Grace E. Kissling, and Fernando Suarez
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Adenoma ,Male ,medicine.medical_specialty ,Mice, Inbred Strains ,Weight Gain ,Toxicology ,Article ,Mice ,Liver Neoplasms, Experimental ,Neoplasms ,Internal medicine ,medicine ,Chronic Progressive Nephropathy ,Animals ,Inhalation exposure ,Inhalation Exposure ,Kidney ,Dose-Response Relationship, Drug ,Inhalation ,Chemistry ,Carcinoma ,Methyl n-Butyl Ketone ,Hyperplasia ,medicine.disease ,Survival Analysis ,Kidney Neoplasms ,Rats, Inbred F344 ,Rats ,Endocrinology ,medicine.anatomical_structure ,Renal papilla ,Toxicity ,Carcinogens ,Female - Abstract
Methyl isobutyl ketone (MIBK) is primarily used as a denaturant for rubbing alcohol, as a solvent and in the manufacture of methyl amyl alcohol. Inhalation of vapors is the most likely route of exposure in the work place. In order to evaluate the potential of MIBK to induce toxic and carcinogenic effects following chronic exposure, groups of 50 male and 50 female F344/N rats and B6C3F1 mice were exposed to MIBK at concentrations of 0, 450, 900, or 1800 ppm by inhalation, 6 h/day, 5 days per week for 2 years. Survival was decreased in male rats at 1800 ppm. Body weight gains were decreased in male rats at 900 and 1800 ppm and in female mice at 1800 ppm. The primary targets of MIBK toxicity and carcinogenicity were the kidney in rats and the liver in mice. In male rats, there was increased mineralization of the renal papilla at all exposure concentrations. The incidence of chronic progressive nephropathy (CPN) was increased at 1800 ppm and the severity was increased in all exposed groups. There were also increases in renal tubule hyperplasia at all exposure concentrations, and in adenoma and adenoma or carcinoma (combined) at 1800 ppm; these lesions are thought to represent a continuum in the progression of proliferative lesions in renal tubule epithelium. These increases may have resulted from the increased severity of CPN, either through α2μ-globulin-dependent or -independent mechanisms. An increase in mononuclear cell leukemia at 1800 ppm was an uncertain finding. Adrenal medulla hyperplasia was increased at 1800 ppm, and there was a positive trend for increases in benign or malignant pheochromocytomas (combined). In female rats, there were increases in the incidence of CPN in all exposure concentrations and in the severity at 1800 ppm, indicating that CPN was increased by mechanisms in addition to those related to α2μ-globulin. There were renal mesenchymal tumors, which have not been observed in historical control animals, in two female rats at 1800 ppm. The relationship of these tumors to exposure to MIBK was uncertain. Hepatocellular adenomas, and adenoma or carcinoma (combined) were increased in male and female mice exposed to 1800 ppm. There were also treatment-related increases in multiple adenomas in both sexes.
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- 2008
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146. Emergency Obstetric Care, Essentialities for Prevention of Maternal/Neonatal Mortality/Morbidity
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S, Chhabra, primary
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- 2017
- Full Text
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147. Concerns about Validity of Caesarian Section for Foetal Distress with No Risk in Mother – Baby
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S, Chhabra, primary
- Published
- 2017
- Full Text
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148. Research Article
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S, Chhabra, primary
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- 2017
- Full Text
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149. Effect of NOx level on secondary organic aerosol (SOA) formation from the photooxidation of terpenes
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Jesse H. Kroll, Richard C. Flagan, Nathan F. Dalleska, John H. Seinfeld, Armin Sorooshian, Paul O. Wennberg, D. C. McCabe, Nga L. Ng, Arthur W. H. Chan, Shane M. Murphy, A. J. Kwan, P. S. Chhabra, and Jason D. Surratt
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chemistry.chemical_classification ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,Monoterpene ,010501 environmental sciences ,Photochemistry ,01 natural sciences ,Aerosol ,chemistry.chemical_compound ,Hydrocarbon ,chemistry ,13. Climate action ,Yield (chemistry) ,Longifolene ,Isomerization ,NOx ,Isoprene ,0105 earth and related environmental sciences - Abstract
Secondary organic aerosol (SOA) formation from the photooxidation of one monoterpene (α-pinene) and two sesquiterpenes (longifolene and aromadendrene) is investigated in the Caltech environmental chambers. The effect of NOx on SOA formation for these biogenic hydrocarbons is evaluated by performing photooxidation experiments under varying NOx conditions. The NOx dependence of α-pinene SOA formation follows the same trend as that observed previously for a number of SOA precursors, including isoprene, in which SOA yield (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted) decreases as NOx level increases. The NOx dependence of SOA yield for the sesquiterpenes, longifolene and aromadendrene, however, differs from that determined for isoprene and α-pinene; the aerosol yield under high-NOx conditions substantially exceeds that under low-NOx conditions. The reversal of the NOx dependence of SOA formation for the sesquiterpenes is consistent with formation of relatively low-volatility organic nitrates, and/or the isomerization of large alkoxy radicals leading to less volatile products. Analysis of the aerosol chemical composition for longifolene confirms the presence of organic nitrates under high-NOx conditions. Consequently the formation of SOA from certain biogenic hydrocarbons such as sesquiterpenes (and possibly large anthropogenic hydrocarbons as well) may be more efficient in polluted air.
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- 2007
- Full Text
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150. Secondary organic aerosol formation from m-xylene, toluene, and benzene
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Nga L. Ng, Richard C. Flagan, Jesse H. Kroll, Arthur W. H. Chan, P. S. Chhabra, and John H. Seinfeld
- Subjects
chemistry.chemical_classification ,Atmospheric Science ,Radical ,respiratory system ,Photochemistry ,m-Xylene ,behavioral disciplines and activities ,Toluene ,Aerosol ,chemistry.chemical_compound ,Hydrocarbon ,chemistry ,Benzene ,NOx ,Oxidation rate - Abstract
Secondary organic aerosol (SOA) formation from the photooxidation of m-xylene, toluene, and benzene is investigated in the Caltech environmental chambers. Experiments are performed under two limiting NOx conditions; under high-NOx conditions the peroxy radicals (RO2) react only with NO, while under low-NOx conditions they react only with HO2. For all three aromatics studied (m-xylene, toluene, and benzene), the SOA yields (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted) under low-NOx conditions substantially exceed those under high-NOx conditions, suggesting the importance of peroxy radical chemistry in SOA formation. Under low-NOx conditions, the SOA yields for m-xylene, toluene, and benzene are constant (36%, 30%, and 37%, respectively), indicating that the SOA formed is effectively nonvolatile under the range of Mo(>10 μg m−3) studied. Under high-NOx conditions, aerosol growth occurs essentially immediately, even when NO concentration is high. The SOA yield curves exhibit behavior similar to that observed by Odum et al. (1996, 1997a, b), although the values are somewhat higher than in the earlier study. The yields measured under high-NOx conditions are higher than previous measurements, suggesting a "rate effect" in SOA formation, in which SOA yields are higher when the oxidation rate is faster. Experiments carried out in the presence of acidic seed aerosol reveal no change of SOA yields from the aromatics as compared with those using neutral seed aerosol.
- Published
- 2007
- Full Text
- View/download PDF
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