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When it comes to the measurement of yield stress, the experimental procedure appears to play a significant role. Using a series of experiments, in which the effects of time dependence and shear banding were identified and taken into account, we determined the dynamic and static yield stresses of the materials as unique, test-independent properties. We studied the shear rheological properties of an aqueous suspension of Laponite®, which is a highly time-dependent (thixotropic) material. To minimize the irreversible effect of aging on its material properties, the Laponite® dispersion was aged for 347 days under a controlled environment. For comparison, an aqueous solution of Carbopol®—a slightly time-dependent material—was also investigated. The peak values of the shear stress evolution in constant shear rate tests were compared with the static and dynamic yield stress values. We noticed that, as the shear rate is reduced the peak stress value tends asymptotically to the dynamic yield stress for the slightly time-dependent material, but to slightly above the static yield stress for the thixotropic material. For the Laponite® suspension, at relatively low shear rates, we observed that peak stresses are influenced by shear banding. By simulating stress evolution curves using stress step-changes, we eliminated the influence of shear banding and discovered that the lowest yielding point coincides with the static yield stress. In addition, we provided the complete flow curve for the Laponite® suspension, showing the role of the static and dynamic yield stresses, and the unattainable zone which is closely related to steady shear banding effects. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) has been detected in the microbiota of wildlife, yet little is known about the origin and impact within the ecosystem. Due to the shortage of nonepizootic surveillance, there is limited understanding of the natural prevalence and circulation of AMR bacteria in the wild animal population, including avian species. In this surveillance study, feces from wild birds in proximity to the River Cam, Cambridge, England, were collected and Pseudomonas spp. were isolated. Of the 115 samples collected, 24 (20.9%; 95% CI, 12.6%‒29.2%) harbored Pseudomonas spp. of which 18 (75%; 95% CI, 58%‒92%) had a multiple antibiotic resistance (MAR) index greater than 0.2. No Pseudomonas spp. isolate in this study was pansusceptible. Resistance was found among the 24 isolates against ciprofloxacin (87.5%; 95% CI, 74.3%‒100%) and cefepime (83.3%; 95% CI, 68.4%‒98.2%), both of which are extensively used to treat opportunistic Pseudomonas spp. infections. The prevalence of Pseudomonas spp. in the wild bird feces sampled during this study is greater than previous, similar studies. Additionally, their multidrug resistance profile provides insight into the potential risk for ecosystem contamination. It further highlights the importance of a One Health approach, including ongoing surveillance efforts that help to develop the understanding of how wildlife, including avifauna, may contribute and disperse AMR across the ecosystem. [ABSTRACT FROM AUTHOR]

SGTs (small glutamine-rich TPR-containing proteins) are dimeric proteins that belong to the class of co-chaperones characterized by the presence of TPR domains (containing tetratricopeptide repeats). Human (SGTA) and yeast (Sgt2) SGTs are characterized by three distinct domains: an N-terminal dimerization domain, a central TPR-domain important for binding to other proteins (chaperones included) and a C-terminal domain involved in hydrophobic interactions. Both these SGTs are involved in the cellular PQC (protein quality control) system, as they interact with chaperones and have functions that aid stress recovery. However, there are differences between them, such as structural features and binding specificities, that could be better understood if other orthologous proteins were studied. Therefore, we produced and characterized a putative SGT protein, designated AaSGT, from the mosquito Aedes aegypti , which is a vector of several diseases, such as dengue and Zika. The protein was produced as a folded dimer which was stable up to 40 °C and was capable of binding to AaHsp90 and fully protecting a model protein, α-synuclein, from aggregation. The conformation of AaSGT was investigated by biophysical tools and small angle X-ray scattering, which showed that the protein had an elongated conformation and that its C-terminal domain was mainly disordered. The results with a C-terminal deletion mutant supported these observations. Altogether, these results are consistent with those from other functional SGT proteins and add to the understanding of the PQC system in Aedes aegypti , an important aim that may help to develop inhibitory strategies against this vector of neglected diseases. [Display omitted] • AaSGT provides phenotype complementation in yeast using a heat sensitivity assay. • AaSGT is capable of fully protecting α-Synuclein from aggregation. • AaSGT has an elongated conformation with a disordered C-terminus. [ABSTRACT FROM AUTHOR]

• Aqueous solvation significantly influences the geometric and electronic parameters of diclofenac. • The diclofenac exhibits selective intermolecular hydrogen bonding, primarily with the atom O of group carbonyl and H of group hydroxyl. • Certain hydrogen bonds in diclofenac demonstrate prolonged mean residence times, indicating strong interactions. • Hydrogen bonds in diclofenac -water interactions vary in strength, with some approaching covalent bond characteristics. • Intramolecular NH⋯OH and NH⋯Cl hydrogen bonds crucially affect DDEA's crystal growth and solubility. Diclofenac, a widely used non-steroidal anti-inflammatory drug with analgesic, anti-inflammatory, and antipyretic properties, presents a challenge in oral administration due to its low aqueous solubility and subsequent low bioavailability. This issue, primarily attributed to the drug's high hydrophobicity, can lead to adverse side effects. To address this, our study delves into the aqueous solvation process of diclofenac through molecular modeling, employing both Carr-Parrinello molecular dynamics and Density Functional Theory. This combined approach enables a comprehensive investigation of the molecular interactions that influence solubility, encompassing non-polar interactions (van der Waals dispersion forces), dipole interactions, and hydrogen bonding. Our results highlight the formation of intermolecular interactions with water molecules through OH⋯O water and CO⋯H water hydrogen bonds. Additionally, we observe intramolecular hydrogen bonds within diclofenac (NH⋯OH and NH⋯Cl) and weaker interactions involving CH⋯Cl. Notably, the protonation of diclofenac contributes to molecular rigidity, hindering hydrogen bonding with adjacent water molecules further. These insights offer a deeper understanding of the solubility challenges associated with diclofenac, paving the way for improved drug formulations that enhance bioavailability. The application of Carr-Parrinello molecular dynamics and density functional theory in this study highlights their valuable role in addressing complex drug solubility and design issues. [ABSTRACT FROM AUTHOR]

Objective A Modified Incremental Step Test (MIST) performed in the home may facilitate entirely home-based pulmonary rehabilitation programs. The aims of this study were to investigate the reliability and responsiveness, and the utility of the MIST for exercise prescription in people with stable chronic lung disease. Methods The MIST was undertaken at the center and home in random order, before and after pulmonary rehabilitation, with 2 tests at each time point. Reliability was assessed using intraclass correlation coefficient. Responsiveness was evaluated as effect size. The minimal important difference was appraised using distribution and anchor-based methods. In a substudy, physiological responses to MIST were measured by a portable metabolic system, followed by a constant step rate test at 60% of peak oxygen uptake (VO2peak), to evaluate utility for exercise prescription. Results Forty-six participants were recruited (29% of eligible candidates). There was excellent reliability for number of steps recorded in home- and center-based settings (intraclass correlation coefficient = 0.954, 95% CI = 0.915–0.976). A small-moderate effect size was demonstrated following pulmonary rehabilitation (0.34), and the minimal detectable change was 7 steps. All participants in the substudy achieved 60% of VO2peak and achieved steady state by the fourth minute, with 60% of VO2peak corresponding to a mean 37% (95% CI = 29–44) of the MIST final level. Conclusions The MIST is reliable and responsive to pulmonary rehabilitation in people with stable chronic respiratory disease. It provides new opportunities to assess exercise capacity, prescribe exercise training, and reassess exercise program outcomes in environments where established field walking tests are not feasible. Impact Pulmonary rehabilitation is a highly effective treatment that is underutilized worldwide. Home-based pulmonary rehabilitation may improve access for patients and deliver equivalent clinical outcomes but is limited by the availability of a robust exercise test that can be used at home to assess exercise capacity and prescribe training intensity. This study tested the clinimetric properties of the MIST and demonstrated a new way to assess exercise capacity, prescribe exercise training of an appropriate intensity, and reassess exercise capacity in environments where established field walking tests are not feasible. [ABSTRACT FROM AUTHOR]

We introduce a constitutive model to describe the rheological behavior of gelled waxy crude oil. The irreversible time-dependence effects were experimentally characterized and incorporated into the model. The model is developed with basis on the data of standard rheological tests to determine the parameters of novel material functions that arise in the model development procedure, namely, flow curve, destruction, and construction tests. The fluidity is directly employed as the indicator of the structuring level of the material. Good agreement is observed between the model predictions and the data, corroborating its potential as a useful tool in the study of start-up flows of gelled crudes in pipelines. [ABSTRACT FROM AUTHOR]

The aim of this work is to evaluate the fractionation of E. globulus industrial kraft liquor by ultrafiltration. A sequential membrane process, using three tubular membranes with nominal cut-offs of 5, 15 and 50 kDa, was applied and the results showed that ultrafiltration is an efficient process for kraft liquor fractionation according to its molecular weight. The obtained ultrafiltration fractions, retentates from 5, 15 and 50 kDa membranes and also permeate from 5 kDa membrane, were studied and the differences between its composition and properties were assessed. In addition, the lignins in fractions were isolated by acid precipitation and studied through nitrobenzene oxidation and 13 C and 31 P NMR, being able to establish the differences in their composition and structural characteristics and consequently find the more adequate commercial application as high added-value products. Lignin isolated from the retentate of 50 kDa membrane shows the higher molecular weight and the higher content of carbohydrates and inorganics. On the other hand, from the permeate of 5 kDa membrane it was obtained the less contaminated lignin and the one with the highest content of uncondensed structures and the highest DC, representing an important source of phenolic monomers through oxidative depolymerization. [ABSTRACT FROM AUTHOR]

The recovery of purified fractions of vanillin and syringaldehyde (V&S) from an oxidized lignin medium has attracted considerable attention driven by the high added value of these products and the importance of lignin valorization processes in biorefineries. Polymeric resins with high specific area can be a viable option for the adsorption of aromatic compounds in polar solvents and desorption with less polar solvents for their recovery. In this work, mono-component batch and fixed bed adsorption experiments were performed with V&S on Sepabeads SP700 in ethanol:water (90:10, % V/V) solutions to obtain the respective isotherm models at 298 K and 313 K. The adsorption behaviors of V&S were described by Linear and Freundlich models. On the perspective of the real application of Sepabeads SP700 for recovery of V&S, fixed bed was first loaded with an aqueous solution of each compound and then desorption was performed with ethanol:water (90:10, % V/V). More than 84% of each compound was readily desorbed within 6 bed volumes, yielding concentration factors between 19-fold and 67-fold, relative to the inlet feed concentration. The desorption histories at the outlet of the fixed bed were successfully described by the mathematical model comprising the equilibrium isotherms and linear driving force rate equations to describe the diffusional mass transfer inside the resin. This work demonstrates that the adsorption of V&S from aqueous solution into Sepabeads SP700 bed and desorption with ethanol:water (90:10, % V/V) solution is a promising approach for the recovery of these compounds from lignin oxidation mixture. The high level of concentration achieved with this strategy and the type of solvent used is favorable for any further processing step, such as crystallization or spray drying. [ABSTRACT FROM AUTHOR]

Pulp and paper mill and biorefinery side-streams are rich in lignin which can be partially converted to vanillin and syringaldehyde through an oxidation process. These value-added compounds can be recovered with an integrated separation process encompassing an adsorption step. In this work the potential of a macroporous polymeric resin, Sepabeads SP700, was assessed. The resin was characterized regarding particle size, solid density, apparent density and particle porosity by means of laser dispersion, helium pycnometry and mercury intrusion porosimetry, respectively. Values within the ranges given by supplier were achieved: solid density, apparent density, particle size and particle porosity were 1294 g L −1 , 1012 g L −1 , 483 μm and 0.73 mL pores mL −1 particle , respectively. Batch equilibrium isotherms for three different temperatures 283/288, 298 and 333 K were found for vanillin and syringaldehyde in aqueous solutions. Experimental results were fitted to Langmuir and Freundlich isotherm models. Equilibrium isotherms were validated by fixed bed studies at different temperatures and feed concentrations. A mathematical model comprising the equilibrium isotherms, linear driving force approximation, and intraparticle mass transfer resistances was used to describe the adsorption/desorption histories of concentration at the outlet of the fixed bed experiments. Although Langmuir model reasonably fit to the experimental results, the empirical Freundlich model was best to describe the experimental results for equilibrium concentrations bellow 1 g L −1 . [ABSTRACT FROM AUTHOR]

The Ordinary Differential Equations (ODEs) of dynamic models that are used in process monitoring, control or optimization, are not only functions of time and states, but also of measured variables. So far two possibilities for the numerical integration of such ODEs were given: (i) a fixed step size integration schema could be applied, matching the step size to the time instances of the measurements; or (ii) using an adaptive step size method while interpolating the measurements. While fixed step size methods are computationally expensive, the repetitive interpolation of measurements for the application of adaptive step size methods is prone to errors and time prohibitive, especially for great numbers of measured variables. In this paper, an adaptive step size numerical integration method is proposed and evaluated for dynamic neural network/hybrid semi-parametric models. The method evaluates the ODEs only at time instances at which online measurements are available and adapts the step size according to those time instances. The numerical solution of the ODEs is provided at time instances which are specified by the user, i.e. at time instances of offline measured states. The rationale behind the proposed method is carefully analyzed, and it is demonstrated that its application along with a hybrid model/dynamic neural network model can result into a significant reduction of number of function evaluations, in the studied cases about 50%, while adhering user specified error tolerances for the numerical integration. In addition, the mutual interference between step-size adaption, parameter identification, coping of the neural network and model performance is studied, a fact that other studies have paid little to no attention. [ABSTRACT FROM AUTHOR]

This systematic review searched for the evidence to use bovine teeth as substitutes for human teeth in laboratory studies testing several properties. The PubMed/MEDLINE, Web of Science, Lilacs (Bireme), BBO and Scopus electronic databases were searched to select laboratorial studies comparing the human teeth with bovine teeth. English and Spanish languages, without date restriction, were included. The search was performed using the keywords: bovine tooth, human tooth, root dentin, enamel and coronary dentin. It was retrieved 1544 potentially eligible articles. 157 articles were indicated for full-text analysis and 79 studies were excluded. At the end of the selection, 78 articles were included in the review. Of the 60 articles evaluated, 15.5% indicated bovine teeth as substitutes for human teeth in laboratory studies, 15.5% indicated substitution with caution, 31% presented the possibility of substitution, 8.7% did not indicate the substitution and 29.3% did not specify the decision. The search showed that in general there is the possibility of human tooth replacement by bovine, both for enamel and dentin substrates, in microleakage studies, organic and inorganic analysis, coefficient of thermal expansion, spectrofluorometry, hardness and microhardness, morphology and radiodensity. [ABSTRACT FROM AUTHOR]

Background/objectives: Flaxseed has functional properties in the reduction of the risk of chronic non-communicable diseases such as cardiovascular disease, diabetes and cancer. Regardless of its high energy density, the consumption of flaxseed tends to promote body weight maintenance. The purpose of this study was to evaluate energy and macronutrient balance after flaxseed consumption. Subjects/methods: Twenty four healthy volunteers were allocated into 3 experimental groups, when they consumed flaxseed (FS), defatted flaxseed flour (FF), or flaxseed oil (FO). During the control period they were provided a diet without flaxseed products for 7-9 days. Following that diets containing 70 g of one of the flaxseed products were consumed for another 7-9 day- period. Test foods were consumed exclusively in the laboratory and fecal excretion was collected during the study. There was a higher energy excretion (P < 0.05) in the FF and FS groups, compared to their control and FO group. Results: The excretions of total lipid and the PUFA α-linolenic acid were higher in FS group (P < 0.05). Conclusions: The intake of 70 g/day of FS and FF raised lipid and energy excretion, which may mitigated the effect of flaxseed consumption on body weight. [ABSTRACT FROM AUTHOR]

Technologies and processes for lignocellulosic conversion in biorefineries are emergent subjects of research for which a reliable analysis of raw materials and quantification of yields of reaction products are required. This paper presents the development of an analytical method, using solid-phase extraction (SPE), for application to the reaction mixture of the oxidation of wood-derived lignin. The aim of the method is to extract the high value added aldehydes for quantification by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). SPE and conventional liquid−liquid extraction (LLE) were evaluated and compared concerning recoveries and precision: (i) solutions of standard phenolic compounds (in alkaline medium and in lignin as matrix) and (ii) real samples and spiked real samples. The presence of lignin in the solutions decreases the recoveries of compounds from about 100% (no lignin) to 91% (for prepared solutions of lignin) and 94% (for real samples). This decrease was clearly evident with the increase of concentration of phenolic compounds in spiked real samples. The recovery averages and precision of SPE were higher than those of LLE and less affected by the presence of lignin. The results gathered and discussed in this work revealed SPE as an alternative to LLE: it is less time-consuming and has higher accuracy and precision for the quantification of phenolic compounds as reaction products of lignin oxidation. [ABSTRACT FROM AUTHOR]

Liquid−liquid equilibrium experimental data for refined sunflower seed oil, artificially acidified with commercial oleic acid or commercial linoleic acid and a solvent (ethanol water), were determined at 298.2 K. This set of experimental data and the experimental data from Cuevas et al.,(1) which were obtained from (283.2 to 333.2) K, for degummed sunflower seed oil-containing systems were correlated using NRTL and UNIQUAC models with temperature-dependent binary parameters. The deviation between experimental and calculated compositions presented average values of (1.13 and 1.41) % for NRTL and UNIQUAC equations, respectively, indicating that the models were able to correctly describe the behavior of compounds under different temperature and solvent hydration. [ABSTRACT FROM AUTHOR]

Plasma edge turbulence in Tokamak Chauffage Alfvén Brésilien (TCABR) [R. M. O. Galvão et al., Plasma Phys. Contr. Fusion 43, 1181 (2001)] is investigated for multifractal properties of the fluctuating floating electrostatic potential measured by Langmuir probes. The multifractality in this signal is characterized by the full multifractal spectra determined by applying the wavelet transform modulus maxima. In this work, the dependence of the multifractal spectrum with the radial position is presented. The multifractality degree inside the plasma increases with the radial position reaching a maximum near the plasma edge and becoming almost constant in the scrape-off layer. Comparisons between these results with those obtained for random test time series with the same Hurst exponents and data length statistically confirm the reported multifractal behavior. Moreover, the persistence of these signals, characterized by their Hurst exponent, present radial profile similar to the deterministic component estimated from analysis based on dynamical recurrences. [ABSTRACT FROM AUTHOR]

The present paper reports phase equilibrium experimental data for two systems composed by peanut oil or avocado seed oil + commercial oleic acid + ethanol + water at 298.2 K and different water contents in the solvent. The addition of water to the solvent reduces the loss of neutral oil in the alcoholic phase and improves the solvent selectivity. The experimental data were correlated by the NRTL and UNIQUAC models. The global deviations between calculated and experimental values were 0.63 % and 1.08 %, respectively, for the systems containing avocado seed oil. In the case of systems containing peanut oil those deviations were 0.65 % and 0.98 %, respectively. Such results indicate that both models were able to reproduce correctly the experimental data, although the NRTL model presented a better performance. [ABSTRACT FROM AUTHOR]

In the present work, we investigate the ability of recently proposed computational operators to characterize the problem of pattern formation by fluid flow and mass transport in a viscous binary fluid mixture under osmosedimentation. We perform a numerical investigation of these patterns using three computational operators (R² → R), computed from the spatial mass distribution, the streamlines, and the velocity fields. Our main goal is to demonstrate the ability of these computational operators to distinguish different dynamical regimes in the complex patterns arising from the osmosedimentation process. [ABSTRACT FROM AUTHOR]

AbstractThe study of the holm oak forests of the lower and upper mesomediterranean of the south of the Iberian Peninsula, and new syntaxons of holm oak forests not assigned until now are contributed. The plant dynamics is provided and completed, and the importance of the learning of plant description and dynamics by university students, future environmental managers, is specified. Taking into account the strong anthropic action with the consequent destruction of holm oak forests, it is necessary to enhance the knowledge of plant dynamics to decipher the potential vegetation, and to be able to apply the vegetation series as a basis for agronomic and forestry management. In this work, we propose a new vegetation series. We propose the association Aristolochio baeticae-Quercetum rotundifoliae nova for the biogeographic sector Granadino-Almijarense (Montes de Málaga) and as a first dynamic stage of the microforest of Olea europea var. sylvestris obtained by deforestation. The study of the Iberian olive groves allows us to propose two new associations Aristolochio baeticae-Oleetum sylvestris and Ephedro fragilis-Oleetum sylvestris. [ABSTRACT FROM AUTHOR]

Accessible Summary: What is known on the subject?: Trauma among psychiatric nurses and other healthcare workers is related to workplace violence, but other risk factors may also contribute, including those occurring before, during or after workplace violence. What does this paper add to existing knowledge?: Most previously identified PTSD risk factors were not tested or supported in research with psychiatric nurses, although there is promising evidence for risk factors including severe or injurious assault, cumulative exposure, burnout, and other worker characteristics.We identify directions for research needed to improve knowledge, including collecting data before nurses experience workplace violence, defining workplace risk factors consistently and conducting and reporting qualitative analysis. What are the implications for practice?: Provide training in risk assessment and violence prevention to psychiatric nurses.Offer mental health support to those exposed to violence, especially with cumulative exposure. Introduction: Psychiatric nurses are at risk of workplace violence and post‐traumatic stress disorder (PTSD). There is limited understanding of pre‐trauma and post‐trauma risk factors. Aim: Our aim was to review factors associated with workplace PTSD in psychiatric nurses. Method: We searched quantitative and qualitative studies from 1980 to 2019 in 23 databases plus abstracts for studies on psychiatric hospital nursing staff, potentially traumatic workplace events, workplace factors and PTSD. Following duplicate abstract (n = 10,064) and full‐text (n = 199) screening, data were extracted in duplicate from 19 studies. Using best‐fit framework synthesis, we identified workplace violence, pre‐trauma and post‐trauma risk factors. Results: Six variables yielded evidence in at least two empirical studies scoring at least 6/8 on a quality measure, or one such study plus more than one other study ("promising": severe/injurious assault, cumulative exposure, burnout, poor mental health, low compassion satisfaction, neuroticism). Four were supported by at least one better quality study or at least two others ("suggestive": gender, poor training, any physical aggression exposure, compassion fatigue). Discussion: Pre‐trauma measures, consistent definitions of workplace exposures and thorough reporting of quantitative results are needed to improve research. Implications for Practice: Violence prevention and mental health care for exposed nurses appear the most promising targets for PTSD prevention. Therefore, it is particularly important to understand workplace violence and mental health among nurses working in psychiatric hospitals. [ABSTRACT FROM AUTHOR]

Rationale: Depression is often associated with memory impairment, a clinical feature of Alzheimer's disease (AD), but no effective treatment is available. 7-Chloro-4-(phenylselanyl) quinoline (4-PSQ) has been studied in experimental models of diseases that affect the central nervous system. Objectives: The pharmacological activity of 4-PSQ in depressive-like behavior associated with memory impairment induced by acute restraint stress (ARS) in male Swiss mice was evaluated. Methods: ARS is an unavoidable stress model that was applied for a period of 240 min. Ten minutes after ARS, animals were intragastrically treated with canola oil (10 ml/kg) or 4-PSQ (10 mg/kg) or positive controls (paroxetine or donepezil) (10 mg/kg). Then, after 30 min, mice were submitted to behavioral tests. Corticosterone levels were evaluated in plasma and oxidative stress parameters; monoamine oxidase (MAO)-A and MAO -B isoform activity; mRNA expression levels of kappa nuclear factor B (NF-κB); interleukin (IL)-1β, IL-18, and IL-33; phosphatidylinositol-se-kinase (PI3K); protein kinase B (AKT2), as well as acetylcholinesterase activity were evaluated in the prefrontal cortex and hippocampus. Results: 4-PSQ attenuated the depressive-like behavior, self-care, and memory impairment caused by ARS. Based on the evidence, we believe that effects of 4-PSQ may be associated, at least in part, with the attenuation of HPA axis activation, attenuation of alterations in the monoaminergic system, modulation of oxidative stress, reestablishment of AChE activity, modulation of the PI3K/AKT2 pathway, and reduction of neuroinflammation. Conclusions: These results suggested that 4-PSQ exhibited an antidepressant-like effect and attenuated the memory impairment induced by ARS, and it is a promising molecule to treat these comorbidities. [ABSTRACT FROM AUTHOR]

This paper offers an in-depth look into beam shaping and polarization control as two of the most promising techniques for improving industrial laser cutting of metal sheets. An assessment model is developed for the study of such effects. It is built upon several modifications to models as available in literature in order to evaluate the potential of a wide range of considered concepts. This includes different kinds of beam shaping (achieved by extra-cavity optical elements or asymmetric diode staking) and polarization control techniques (linear, cross, radial, azimuthal). A fully mathematical description and solution procedure are provided. Three case studies for direct diode lasers follow, containing both experimental data and parametric studies. In the first case study, linear polarization is analyzed for any given angle between the cutting direction and the electrical field. In the second case several polarization strategies are compared for similar cut conditions, evaluating, for example, the minimum number of spatial divisions of a segmented polarized laser beam to achieve a target performance. A novel strategy, based on a 12-division linear-to-radial polarization converter with an axis misalignment and capable of improving cutting efficiency with more than 60%, is proposed. The last case study reveals different insights in beam shaping techniques, with an example of a beam shape optimization path for a 30% improvement in cutting efficiency. The proposed techniques are not limited to this type of laser source, neither is the model dedicated to these specific case studies. Limitations of the model and opportunities are further discussed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • SP700 was used in the adsorption studies of vanillic (VA) and syringic (SA) acids. • Batch experiments of VA and SA in water were fitted with Bi-Langmuir model. • Dynamic experiments were performed for different temperatures and feed concentrations. • Breakthroughs were described with the axially dispersed plug flow model. • More than 83% of VA and SA were readily desorbed with ethanol:water (90:10 %V/V). Abstract In this work the adsorption of vanillic (VA) and syringic (SA) acids onto the nonpolar resin SP700 was investigated aiming to collect data to evaluate their separation from a lignin oxidation mixture containing other phenolic compounds. The respective adsorption equilibrium isotherms in aqueous solutions were assessed at three different temperatures 288, 298 and 333 K and experimental results were fitted with Bi-Langmuir isotherm model. Maximum adsorption capacities of 0.486 g g−1 dry resin and 0.407 g g−1 dry resin were obtained for VA and SA, respectively. Dynamic studies at different temperatures and feed concentrations were performed and a mathematical model comprising the Bi-Langmuir equilibrium isotherm, axial dispersed plug flow, intraparticle mass transfer resistance expressed with linear driving force approximation with no temperature gradients and constant porosity along the bed successfully described the adsorption concentration histories at the outlet of the fixed bed. More than 83% of each phenolic acid was readily eluted within 5 min elution with ethanol:water (90:10 %V/V) solution allowing obtaining a final concentrated solution with 5.8–11.7 g L−1. [ABSTRACT FROM AUTHOR]

In this work, we report on a technique—namely, the photoinduced magnetotunneling technique—which allows the direct experimental observation of tunneling of holes through valence-band Landau levels in n-i-n double-barrier resonant tunneling structures. Photocurrent–voltage curves exhibit several peaks associated with the complex nature of the dispersion of holes under parallel electric and magnetic fields applied to the sample. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Muscle degenerative diseases such as Duchenne Muscular Dystrophy are incurable and treatment options are still restrained. Understanding the mechanisms and factors responsible for muscle degeneration and regeneration will facilitate the development of novel therapeutics. Several recent studies have demonstrated that Galectin-1 (Gal-1), a carbohydrate-binding protein, induces myoblast differentiation and fusion in vitro, suggesting a potential role for this mammalian lectin in muscle regenerative processes in vivo. However, the expression and localization of Gal-1 in vivo during muscle injury and repair are unclear. We report the expression and localization of Gal-1 during degenerative–regenerative processes in vivo using two models of muscular dystrophy and muscle injury. Gal-1 expression increased significantly during muscle degeneration in the murine mdx and in the canine Golden Retriever Muscular Dystrophy animal models. Compulsory exercise of mdx mouse, which intensifies degeneration, also resulted in sustained Gal-1 levels. Furthermore, muscle injury of wild-type C57BL/6 mice, induced by BaCl2 treatment, also resulted in a marked increase in Gal-1 levels. Increased Gal-1 levels appeared to localize both inside and outside the muscle fibers with significant extracellular Gal-1 colocalized with infiltrating CD45+ leukocytes. By contrast, regenerating muscle tissue showed a marked decrease in Gal-1 to baseline levels. These results demonstrate significant regulation of Gal-1 expression in vivo and suggest a potential role for Gal-1 in muscle homeostasis and repair. [ABSTRACT FROM AUTHOR]

Annatto seed oil (ASO) and cupuassu seed fat (CSF) were combined at the ratios: 30:70, 50:50, and 70:30 (% w/w). Their fatty acid profile, nutritional quality, FTIR (Fourier Transform Infrared) spectra, and rheological behavior were evaluated. ASO increased the content of polyunsaturated fatty acids in the blends; whereas CSF conferred higher contents of monounsaturated fatty acids. The blends exhibited low atherogenicity and thrombogenicity indices, suggesting nutritional advantages. The Newtonian fluid behavior and FTIR results suggested that mixing ASO and CSF at different proportions did not affect the functional groups. ASO showed an activation energy value which indicated that this fat viscosity was more sensitive to temperature changes. The Newtonian model proved to be suitable to describe the behavior of samples, according to statistical fit parameters R², χ², and RSS. The resulting blends presented improved physicochemical properties and nutritional attributes, indicating their feasibility for the development of new products. [ABSTRACT FROM AUTHOR]

Xylopia laevigata (Annonaceae), known locally as “meiú” or “pindaíba”, is widely used in folk medicine in Northeastern Brazil. In the present work, we performed phytochemical analyses of the stem of X. laevigata, which led to the isolation of 19 alkaloids: (–)-roemerine, (+)-anonaine, lanuginosine, (+)-glaucine, (+)-xylopine, oxoglaucine, (+)-norglaucine, asimilobine, (–)-xylopinine, (+)-norpurpureine, (+)-N-methyllaurotetanine, (+)-norpredicentrine, (+)-discretine, (+)-calycinine, (+)-laurotetanine, (+)-reticuline, (–)-corytenchine, (+)-discretamine and (+)-flavinantine. The in vitro cytotoxic activity toward the tumor cell lines B16-F10 (mouse melanoma), HepG2 (human hepatocellular carcinoma), K562 (human chronic myelocytic leukemia) and HL-60 (human promyelocytic leukemia) and non-tumor peripheral blood mononuclear cells (PBMCs) was tested using the Alamar Blue assay. Lanuginosine, (+)-xylopine and (+)-norglaucine had the highest cytotoxic activity. Additionally, the pro-apoptotic effects of lanuginosine and (+)-xylopine were investigated in HepG2 cells using light and fluorescence microscopies and flow cytometry-based assays. Cell morphology consistent with apoptosis and a marked phosphatidylserine externalization were observed in lanuginosine- and (+)-xylopine-treated cells, suggesting induction of apoptotic cell death. In addition, (+)-xylopine treatment caused G2/M cell cycle arrest in HepG2 cells. These data suggest that X. laevigata is a potential source for cytotoxic alkaloids. [ABSTRACT FROM AUTHOR]

There are many available methods to measure the human energy consumption. Due to the high cost and small number of laboratories able to perform it, the direct calorimetry and doubly labeled water technique are rarely used to measure the energy expenditure. As consequence, there is an increase use of the indirect calorimetry and bioelectrical impedance analysis methods by researchers and predictive equations by physicians to calculate the total energy requirements in research and in clinic. Objective: To evaluate the basal energy expenditure (GEB) and total energy expenditure (GET) of healthy subjects comparing results of indirect calorimetry (CI), bioelectrical impedance analysis (BIA) and predictive equations such as estimated energy requirements (EER), Fleish, FAO/WHO/UNU 1985 and 2001. Material and methods: It was evaluated the energy expenditure in 81 subjects of both gender by CI and BIA. Of these, the GEB by predictive equations FAO/WHO/ UNU 1985 and 2001 and the GET by EER, Fleisch and FAO/WHO/UNU 1985 and 2001 were calculated. The data was analyzed with the software Sigma Stat for Windows version 2.03 and Dunn's test was used for comparison of mean obtained with methods and equations (p < 0.05). Results: It was verified that 60.5% of the participants were men. The majority of subjects were eutrofic. BIA showed significant differences between men and women. The differences between the values of GEB, obtained by BIA and CI, were statistically significant only for women (p < 0.05) with an underestimation of the GEB results obtained by BIA in relation to those obtained by CI. Significant difference was found between the predictive equations and CI for both sexes, also demonstrating an underestimation of the equations in relation to CI. It was observed an overestimation of GET with the predictive equations of FAO/WHO/UNU/85 and 2001 in relation to EER and Fleisch for both sexes. Conclusion: The estimation of GEB can be carried out by both BIA and CI, although BIA must be used with criteria since it underestimates in a significant way for women. In relation to the predictive equations, overestimation can develop positive energy balance in populations with risks for overweight and obesity. Thus, it is necessary comparisons to identify the limitations of each method. [ABSTRACT FROM AUTHOR]

Multi-robot navigation is a challenging task, especially for many robots, since individual gains may more often than not adversely affect the global gain. This paper investigates the problem of multiple robots moving towards individual goals within a common workspace whereas the motion of every individual robot is deduced by a novel Particle Swarm Optimization (PSO) tuned Feed Forward Neural Network (FFNN). Motion coordination among the robots is implemented using a cooperative coordination algorithm that identifies critical robots and maintains cooperation count while actuating deviation in select robots. The contribution of this paper is twofold; firstly in hybridizing the Artificial Neural Network(ANN) by employing PSO, an evolutionary algorithm, to find optimal values of deviation for every critical robot using velocity and acceleration constraints, secondly ensuing the convergence of the PSO by carrying first and second order stability analysis. Experiments have been carried out to evaluate and validate the efficacy of the proposed coordination schemes by changing the number of robots under hundred different scenarios each, and the founded results demonstrate the efficacy of the proposed schemes. [ABSTRACT FROM AUTHOR]

Background: Although leprosy is largely curable with multidrug therapy, incomplete treatment limits therapeutic effectiveness and is an important obstacle to disease control. To inform efforts to improve treatment completion rates, we aimed to identify the geographic and socioeconomic factors associated with leprosy treatment default in Brazil. Methodology/Principal findings: Using individual participant data collected in the Brazilian national registries for social programs and notifiable diseases and linked as part of the 100 Million Brazilian Cohort, we evaluated the odds of treatment default among 20,063 leprosy cases diagnosed and followed up between 2007 and 2014. We investigated geographic and socioeconomic risk factors using a multivariate hierarchical analysis and carried out additional stratified analyses by leprosy subtype and geographic region. Over the duration of follow-up, 1,011 (5.0%) leprosy cases were observed to default from treatment. Treatment default was markedly increased among leprosy cases residing in the North (OR = 1.57; 95%CI 1.25–1.97) and Northeast (OR = 1.44; 95%CI 1.17–1.78) regions of Brazil. The odds of default were also higher among cases with black ethnicity (OR = 1.29; 95%CI 1.01–1.69), no income (OR = 1.41; 95%CI 1.07–1.86), familial income ≤ 0.25 times Brazilian minimum wage (OR = 1.42; 95%CI 1.13–1.77), informal home lighting/no electricity supply (OR = 1.53; 95%CI 1.28–1.82), and household density of > 1 individual per room (OR = 1.35; 95%CI 1.10–1.66). Conclusions: The findings of the study indicate that the frequency of leprosy treatment default varies regionally in Brazil and provide new evidence that adverse socioeconomic conditions may represent important barriers to leprosy treatment completion. These findings suggest that interventions to address socioeconomic deprivation, along with continued efforts to improve access to care, have the potential to improve leprosy treatment outcomes and disease control. [ABSTRACT FROM AUTHOR]

Highlights • The work is unique as it is first known technique to exploit recurrent neural networks to support Prime Matrix Factorization. • Exploits the implicit content of microblogs to generate distributed representations. • Exploits the explicit factors like likes, favorites, followers and friends to model relationships between hashtags and users more accurately. • Uses implicit and explicit features to performed supported matrix factorization under regularization. • Experimentations show significant improvement over standard prime factorization methods. Abstract Microblogging is one of the most prevalent media for sharing news on the Internet. Microblogging platforms, such as Twitter have proven to be of great success in targeted marketing, alerting about natural disasters and promoting government policies among others; But most of this relevant information in microblogs is side-lined, owing to information overload, rendering any practical utility of the platform as ineffective. Hence, it is crucial to filter data and recommend only relevant information to the users. Interestingly, to pertain and appeal to a certain community, users make the use of hashtags (#), which in turn, helps in the efficient categorization and summarization of microblogs. In this paper, we exploit this advantage through a novel framework for a recommendation system, Distributed Representation based Supported Matrix Factorization (DRSMF) build on top of Probabilistic Matrix Factorization (PMF) and Recurrent Neural Networks (RNNs). The RNNs generate character-level distributed representations for each tweet to overcome the solecistic use of sentence structure in microblogs. The framework further performs a multi-modal analysis on the microblog posts to recommend similar users and hashtags , which assists in countering information-overload. Our framework outperforms standard PMF techniques by the use of constrained regularisation on latent factor representations. [ABSTRACT FROM AUTHOR]

The clinical expression of systemic lupus erythematosus (SLE) is influenced by genetic and environmental factors and therefore varies between ethnicities. Information on the epidemiology of SLE in Brazil is scarce and practically limited to studies conducted in socioeconomically developed regions (South and Southeast). The objective of this study was to describe the clinical and immunological aspects and outcome of a cohort of patients with SLE treated at a university hospital in northeastern Brazil and compare patterns related to age at onset: childhood (cSLE), adult (aSLE), and late (lSLE). A random sample of 414 records (women: 93.5%) were reviewed. The mean age at SLE onset and the mean disease duration were 28.9 ± 10.9 years and 10.2 ± 6.6 years, respectively. Most patients had aSLE (n = 338; 81.6%), followed by cSLE (n = 60; 14.5%) and lSLE (n = 16; 3.9%). The female/male ratio was 6.5:1 in cSLE and 16.8:1 in aSLE; in lSLE, all patients were female (p = 0.05). During follow-up, the cSLE group presented higher rates of nephritis (70% vs. 52.9% vs. 12.5%; p = 0.0001) and leuko/lymphopenia (61.7% vs. 43.8% vs. 56.2%; p = 0.02). No significant differences were found for anti-dsDNA, anti-Sm, and antiphospholipid antibodies. Treatment with immunosuppressants was significantly more common, and higher doses of prednisone were used, in cSLE. The prevalence of cardiovascular diseases were more frequent in lSLE (p = 0.03). No significant differences were found between the three groups with regard to mean damage accrual (SDI), remission, and mortality. Although cSLE presented higher rates of nephritis and leuko/lymphopenia, more frequent use of immunosuppressants and higher prednisone doses than aSLE and lSLE, the three groups did not differ significantly with regard to damage accrual, remission, and mortality. [ABSTRACT FROM AUTHOR]

Buriti oil is an example of an Amazonian palm oil of economic importance. The local population uses this oil for the prevention and treatment of different diseases; however, there are few studies in the literature that evaluate its properties. In this study, detailed chemical and antioxidant properties of Buriti oil were determined. The predominant fatty acid was oleic acid (65.6%) and the main triacylglycerol classes were tri-unsaturated (50.0%) and di-unsaturated-mono-saturated (39.3%) triacylglycerols. The positional distribution of the classes of fatty acids on the triacylglycerol backbone indicated a saturated and unsaturated fatty acid relationship similar in the three-triacylglycerol positions. All tocopherol isomers were present, with a total content of 2364.1 mg·kg-1. α-tocopherol constitutes 48% of the total tocopherol content, followed by γ- tocopherol (45%). Total phenolic (107.0 mg gallic acid equivalent·g-1 oil) and β-carotene (781.6 mg·kg-1) were particularly high in this oil. The highest antioxidant activity against the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) was obtained at an oil concentration of 50 mg·mL-1 (73.15%). The antioxidant activity evaluated by the Oxygen Radical Absorbance Capacity (ORAC) was 95.3 µmol Trolox equivalent·g-1 oil. These results serve to present Buriti oil as an Amazonian resource for cosmetic, food and pharmaceuticals purposes. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of nitrogen doses using urea or coated urea by polymers, in contents of nitrogen and chlorophyll in leaf, agronomic characteristics and yield of corn under no-tillage system, cultivated in Savanna region. The experiment was conducted during the growing season of 2008/09 and 2009/10, in Selvíria - MS in an Oxisol with loamy texture. A randomized block design with four replications was used, disposed in a factorial scheme 4 × 2, being: four N doses (0, 40, 80 and 120 kg ha-1) applied in topdressing, as urea in two forms (conventional and coated by polymers). The polymer that covers the urea is not efficient under the soil and climatic conditions of low altitude Savannah with the use of irrigation, because it provided similar results to conventional urea for agronomic characteristics and grain yield of corn. The increase of N dose influence positively the N and chlorophyll leaf contents, plant height, number of grains per line and mass of 100 grains. The topdressing application of 88 kg ha-1 of N provides maximum grain yield of corn, regardless of the form of urea used. [ABSTRACT FROM AUTHOR]

The Internet explosion makes energy consumption of the ICT sector a global concern. Nowadays, the power consumption of access networks increases rapidly due to the rollout of broadband services. Cable access networks provide Internet access over the existing cable television systems. Among all wired access networks, they have the second biggest user base, which is still growing fast due to the release of the new industry standard, DOCSIS 3.0. Therefore, we expect that cable access networks will play an important role in the ICT sector of future smart cities. In order to boost up bidirectional throughput, DOCSIS 3.0 introduces the channel bonding technology, which could lead to increased power consumption if not properly managed. In this article, we present a few energy-saving algorithms that could be used by the cable operators to improve the energy efficiency of cable access networks using channel bonding. The discussions cover both the network-wide energy-saving algorithm and the customer-side energy-saving algorithm, and provide investigations on the trade-offs between energy-saving and other network performance metrics, including packet delay and protocol overhead. Our numerical results suggest that effective energy saving can be achieved in wideband cable access networks with the proposed algorithms, and the packet delay and protocol overhead can be reduced if we choose the key parameters properly. [ABSTRACT FROM PUBLISHER]

AbstractLongitudinal mosquito surveys were carried out in southern Portugal from 2004 to 2007, in a wetland area (Comporta, District of Setúbal) and around the perimeter of a dam irrigation plant that created the largest artificial lake in Europe, 250 km2(Alqueva, Districts of Évora and Beja). Our aim was to study the diversity, abundance, and seasonal dynamics of mosquitoes, comparing these two different areas, to screen mosquitoes for West Nile Virus (WNV), an arboviral agent already detected in Portugal, because these areas are populated with abundant avian fauna. Monthly collections of adult mosquitoes were carried out by Centers for Disease Control light-traps with CO2and by indoor resting collections. Mosquitoes were identified and screened for arboviruses by reverse transcriptase (RT)-polymerase chain reaction directed toward amplification of a 217-bp fragment of the NS5 gene. Mosquito peak densities were observed in July–August in Comporta and May–June, with a plateau in July–October, in Alqueva. However, densities were far higher in Comporta area (220,821 specimens) than in Alqueva area (9442 specimens), with a clear difference in species distribution, as in Comporta the predominant species was Culex theileri(85%), followed by Aedes caspius(6%), Anopheles atroparvus(4%), and Culex pipiens sensu latu(s.l.) (3%), whereas in Alqueva the predominant species was Cx. pipienss.l. (56%), followed by An. atroparvus(18%), Cx. theileri(14%), and Culiseta longiareolata(9%). Female mosquitoes (8842 in 175 pools) of the species Ae. caspius, An. atroparvus, Culex mimeticus, Cx. pipiensSensu latu(s.l.), Cx. theileri, and Culex univittatuswere screened and found to be negative for WNV genomic RNA. Although there was no detection of WNV sequences in mosquitoes, vigilance should continue as the circulation of virus has been previously detected more than once in Portugal, in humans, animals, and mosquitoes, and in other surrounding Mediterranean countries. [ABSTRACT FROM AUTHOR]

In this work, the toxicological assessment towards filamentous fungi (Penicilliumsp.) as model eukaryotic organisms of sixteen ionic liquids (containing an imidazolium, pyridinium, or cholinium cation) is presented. Amongst these fungi are members which show much higher tolerance towards ionic liquids than any other microorganism so far studied. Furthermore, guided by the paradigm that the choice of an ionic liquid as catalyst can alter the outcome of a given chemical reaction, the ability of ionic liquids to alter the metabolic profile in fungi was studied. The metabolic footprint, as investigated by electrospray ionisation mass spectrometry, revealed that fungal cultures respond to specific ionic liquids by changing their cell biochemistry, resulting in an altered pattern of secondary metabolites. [ABSTRACT FROM AUTHOR]

The aim of this work is to solve the case study singular model involving the Neumann–Robin, Dirichlet, and Neumann boundary conditions using a novel computing framework that is based on the artificial neural network (ANN), global search genetic algorithm (GA), and local search sequential quadratic programming method (SQPM), i.e., ANN-GA-SQPM. The inspiration to present this numerical framework comes through the objective of introducing a reliable structure that associates the operative ANNs features using the optimization procedures of soft computing to deal with such stimulating systems. Four different problems that are based on the singular equations involving Neumann–Robin, Dirichlet, and Neumann boundary conditions have been occupied to scrutinize the robustness, stability, and proficiency of the designed ANN-GA-SQPM. The proposed results through ANN-GA-SQPM have been compared with the exact results to check the efficiency of the scheme through the statistical performances for taking fifty independent trials. Moreover, the study of the neuron analysis based on three and 15 neurons is also performed to check the authenticity of the proposed ANN-GA-SQPM. [ABSTRACT FROM AUTHOR]

Opportunistic networks (OppNets) are a type of challenged network where there is no guaranteed of end-to-path between the nodes for data delivery because of intermittent connectivity, node mobility and frequent topology changes. In such an environment, the routing of data is a challenge since the battery power of the mobile nodes drains out quickly because of multi-routing activities such as scanning, transmitting, receiving, and computational processing, effecting the overall network performance. In this paper, a novel routing protocol for OppNets called Energy-Efficient Check-and-Spray Geocast Routing (EECSG) is proposed, which introduces an effective way of message distribution in the geocasting region to all residing nodes while saving the energy consumption by restricting the unnecessary packet transmission in that region. A Check-and-Spray technique is also introduced to eliminate the overhead of packets in the geocast region. The proposed EECSG is evaluated by simulations and compared against the Efficient and Flexible Geocasting for Opportunistic Networks (GSAF) and the Centrality- Based Geocasting for Opportunistic networks (CGOPP) routing protocols in terms of average latency, delivery ratio, number of messages forwarded, number of dead nodes, overhead ratio, and hop count, showing superior performance. [ABSTRACT FROM AUTHOR]

In recent years, edge computing has emerged as a new concept in the computing paradigm that empowers several future technologies, such as 5G, vehicle-to-vehicle communications, and the Internet of Things (IoT), by providing cloud computing facilities, as well as services to the end users. However, open communication among the entities in an edge based IoT environment makes it vulnerable to various potential attacks that are executed by an adversary. Device authentication is one of the prominent techniques in security that permits an IoT device to authenticate mutually with a cloud server with the help of an edge node. If authentication is successful, they establish a session key between them for secure communication. To achieve this goal, a novel device authentication and key management mechanism for the edge based IoT environment, called the lightweight authentication and key management scheme for the edge based IoT environment (LDAKM-EIoT), was designed. The detailed security analysis and formal security verification conducted by the widely used "Automated Validation of Internet Security Protocols and Applications (AVISPA)" tool prove that the proposed LDAKM-EIoT is secure against several attack vectors that exist in the infrastructure of the edge based IoT environment. The elaborated comparative analysis of the proposed LDAKM-EIoT and different closely related schemes provides evidence that LDAKM-EIoT is more secure with less communication and computation costs. Finally, the network performance parameters are calculated and analyzed using the NS2 simulation to demonstrate the practical facets of the proposed LDAKM-EIoT. [ABSTRACT FROM AUTHOR]

Following the initial idea presented in Amaral et al (2017 Eur. J. Phys38 025206), we address Kelvin’s inversion of coordinates, which exchanges the radial coordinate for its inverse, in arbitrary dimensional electrostatics. For two- and three-dimensional configurations (planar and cylindrical symmetries) detailed analyses are provided. Using this symmetry, which is rather overlooked in usual electromagnetism textbooks, a wide range of problems is correlated showing that some complicated situations are much simpler in a dual description. We also show that the Lagrangian changes by a total derivative term under the studied inversion leading to action invariance. [ABSTRACT FROM AUTHOR]

Objective To identify factors associated with diarrhoea occurrence in children in a city in a middle-income country, with high access to water and sanitation. Methods A case–control study in the city of Salvador, north-eastern Brazil was conducted from November 2002 to August 2004. The study population consisted of children presenting at a health facility. A total of 1688 cases of diarrhoea and 1676 controls were selected. Data collection was by a questionnaire and structured observation during home visits. The explanatory variables were grouped according to a conceptual model defined previously. Analysis was done using a hierarchical approach, to provide a more dynamic view of the transmission characteristics of childhood diarrhoea. Non-conditional logistic regression was used, and odds ratio and population-attributable fractions were estimated. Results Socioeconomic factors contributed most to determining diarrhoea occurrence, followed by interpersonal contact, while factors related to food preparation, the environment and water and sanitation made a smaller contribution. Conclusion The findings indicate that the transmission of diarrhoea is influenced by factors from all hierarchical levels, with interpersonal transmission playing a relatively higher role than previously thought. This is compatible with a predominance of viruses and other agents spread by interpersonal routes including Shigella, Giardia and Cryptosporidium. Diarrhoea control strategies in similar settings (middle-income countries in which a large proportion of the population has access to water and sanitation) must give greater emphasis to policies geared towards reducing person-to-person transmission for the prevention of diarrhoea. [ABSTRACT FROM AUTHOR]