1,659 research outputs found

    Li and Na adsorption on graphene and graphene oxide examined by density functional theory quantum theory of atoms in molecules and electron localization function

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    Adsorption of Li and Na on pristine and defective graphene and graphene oxide (GO) is studied using density functional theory (DFT) structural and electronic calculations, quantum theory of atoms in molecules (QTAIM), and electron localization function (ELF) analyses. DFT calculations show that Li and Na adsorptions on pristine graphene are not stable at all metal coverages examined here. However, the presence of defects on graphene support stabilizes both Li and Na adsorptions. Increased Li and Na coverages cause metal nucleation and weaken adsorption. Defective graphene is associated with the presence of band gaps and, thus, Li and Na adsorptions can be used to tune these gaps. Electronic calculations show that Li– and Na–graphene interactions are Coulombic: as Li and Na coverages increase, the metal valences partially hybridize with the graphene bands and weaken metal–graphene support interactions. However, for Li adsorption on single vacancy graphene, QTAIM, ELF, and overlap populations calculations show that the Li-C bond has some covalent character. The Li and Na adsorptions on GO are significantly stronger than on graphene and strengthen upon increased coverages. This is due to Li and Na forming bonds with both carbon and oxygen GO atoms. QTAIM and ELF are used to analyze the metal–C and metal–metal bonds (when metal nucleation is present). The Li and Na clusters may contain both covalent and metallic intra metal–metal bonds: This effect is related to the adsorption support selection. ELF bifurcation diagrams show individual metal–C and metal–metal interactions, as Li and Na are adsorbed on graphene and GO, at the metal coverages examined here

    Involvement of the Rcs regulon in the persistence of Salmonella Typhimurium in tomatoes

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    It is becoming clear that human enteric pathogens, like Salmonella, can efficiently colonize vegetative and reproductive organs of plants. Even though the bacterium's ability to proliferate within plant tissues has been linked to outbreaks of salmonellosis, little is known about regulatory and physiological adaptations of Salmonella, or other human pathogens, to their persistence in plants. A screen of Salmonella deletion mutants in tomatoes identified rcsA and rcsB genes as those under positive selection. In tomato fruits, populations of Salmonella rcsB mutants were as much as 100-fold lower than those of the wild type. In the follow-up experiments, competitive fitness of rcsA and rcsB mutants was strongly reduced in tomatoes. Bioinformatics predictions identified a putative Salmonella RcsAB binding box (TTMGGAWWAABCTYA) and revealed an extensive putative RcsAB regulon, of which many members were differentially fit within tomatoes

    Analysis of Mandibular Fractures Caused by Work Related Accidents. Retrospective Descriptive Study

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    Indexación: Web of Science; Scielo.El objetivo de este estudio fue evaluar la tendencia de los pacientes con fracturas mandibulares asociados a accidentes laborales. Se realizó un estudio descriptivo retrospectivo en todos los casos de fracturas mandibulares que asistieron al servicio de cirugía maxilofacial del Hospital Clínico Mutual de Seguridad C.Ch.C., Santiago de Chile en un periodo de 4 años (enero 2009 - diciembre 2012). Todas las fracturas mandibulares fueron consignadas. La información fue recopilada a través de revisión de fichas clínicas electrónicas. Entre los años 2009 al 2012 se presentaron un total de 74 pacientes incluidos en el estudio con 102 rasgos de fracturas mandibulares. La fractura más común fue la de cóndilo mandibular (35 pacientes). Se observó una tasa de complicaciones del 8%. Los resultados mostrados en este estudio están en línea con la literatura y el análisis de este reporte provee información para el diseño de planes de prevención de riesgos, especialmente para desarrollar medidas de protección facial. Nivel de Evidencia: Tipo II. Estudio descriptivo.ABSTRACT: The objective of this study was to evaluate the tendency of patients with mandibular fractures associated with working accidents. A retrospective descriptive study was performed in all cases of mandibular fractures who attended the maxillofacial surgery service at the Clinical Hospital Mutual Seguridad C.CH.C. Santiago de Chile, in a 4-year period (January 2009 - December 2012). All mandibular fractures were recorded. The information was collected through review of electronic medical records. Between 2009 and 2012, 74 patients were included in the study with 102 lines of mandibular fractures. The most common fracture was the mandibular condyle (35 patients). The complication rate was 8%. The results shown in this study are in line with the literature and the analysis of this report provides information for the design of risk prevention plans, especially in developing measures of facial protection.http://ref.scielo.org/p5w48

    Impact of Tumor LINE-1 Methylation Level and Neoadjuvant Treatment and Its Association with Colorectal Cancer Survival

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    Recent studies suggest that long-interspersed nucleotide element-1 (LINE-1) hypomethylation is commonly found in colorectal cancer (CRC), and is associated with worse prognosis. However, the utility of LINE-1 methylation on the prognosis of CRC is still controversial, and may be due to the fact that some clinical and pathological features may affect LINE-1 methylation. Thus, the aim of this study was to assess the prognostic value of tumor LINE-1 methylation in CRC, through their association with the CRC clinical and pathological characteristics. Survival of sixty-seven CRC patients was evaluated according to the median of tumor LINE-1 methylation, as well as pathological and oncological variables. We also studied the association between LINE-1 methylation and pathological features, and finally, we assessed the overall and disease-free survival of LINE1 methylation, stratified by neoadjuvant treatment and further checked by multivariate Cox regression to assess the statistical interactions. LINE-1 was hypomethylated in the CRC tumor with respect to the tumor adjacent-free area (p < 0.05), without association with any other clinical and oncological features, nor with overall and disease-free survival rates for CRC. Relevantly, in neoadjuvant treatment, LINE-1 methylation was associated with survival rates. Thus, disease-free and overall survival rates of treated CRC patients were worse in the hypomethylated LINE-1 tumors than those with normal LINE-1 methylation (p = 0.004 and 0.0049, respectively). Indeed, LINE-1 was hypermethylated more in the treated patients than in the non-treated patients (p < 0.05). The present study showed that tumor LINE-1 hypomethylation was associated with worse survival rates in only treated patients. Our data suggest an interactive effect of neoadjuvant treatment and tumor LINE-1 methylation, which could be a specific-tissue biomarker to predict survival of the treated patients, and help to personalize treatment in CRC

    "The Ising model on spherical lattices: dimer versus Monte Carlo approach"

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    We study, using dimer and Monte Carlo approaches, the critical properties and finite size effects of the Ising model on honeycomb lattices folded on the tetrahedron. We show that the main critical exponents are not affected by the presence of conical singularities. The finite size scaling of the position of the maxima of the specific heat does not match, however, with the scaling of the correlation length, and the thermodynamic limit is attained faster on the spherical surface than in corresponding lattices on the torus.Comment: 25 pages + 6 figures not included. Latex file. FTUAM 93-2

    CASSIS: The Cornell Atlas of Spitzer/Infrared Spectrograph Sources. II. High-resolution observations

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    The Infrared Spectrograph (IRS) on board the Spitzer Space Telescope observed about 15,000 objects during the cryogenic mission lifetime. Observations provided low-resolution (R~60-127) spectra over ~5-38um and high-resolution (R~600) spectra over ~10-37um. The Cornell Atlas of Spitzer/IRS Sources (CASSIS) was created to provide publishable quality spectra to the community. Low-resolution spectra have been available in CASSIS since 2011, and we present here the addition of the high-resolution spectra. The high-resolution observations represent approximately one third of all staring observations performed with the IRS instrument. While low-resolution observations are adapted to faint objects and/or broad spectral features (e.g., dust continuum, molecular bands), high-resolution observations allow more accurate measurements of narrow features (e.g., ionic emission lines) as well as a better sampling of the spectral profile of various features. Given the narrow aperture of the two high-resolution modules, cosmic ray hits and spurious features usually plague the spectra. Our pipeline is designed to minimize these effects through various improvements. A super sampled point-spread function was created in order to enable the optimal extraction in addition to the full aperture extraction. The pipeline selects the best extraction method based on the spatial extent of the object. For unresolved sources, the optimal extraction provides a significant improvement in signal-to-noise ratio over a full aperture extraction. We have developed several techniques for optimal extraction, including a differential method that eliminates low-level rogue pixels (even when no dedicated background observation was performed). The updated CASSIS repository now includes all the spectra ever taken by the IRS, with the exception of mapping observations

    Health Seeking Behaviour and Treatment Intentions of Dengue and Fever:A Household Survey of Children and Adults in Venezuela

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    BACKGROUND:Dengue in Venezuela is a major public health problem with an increasing incidence of severe cases. Early diagnosis and timely treatment influences the outcome of dengue illness, as delay in care-seeking is significantly associated with complications leading to severe dengue. We aimed to understand patterns of health seeking behaviour (HSB) in individuals exposed to high dengue incidence in order to improve early attendance to health centres. METHODS:Between September 2013 and February 2014 a cross-sectional household survey was performed in Maracay, Venezuela. Intended HSB of adults and children's parents/guardians was assessed with respect to fever or suspected dengue. Data was collected through structured questionnaires from 105 individuals. RESULTS:Most individuals felt at risk of dengue and believed it could be a deadly disease. In the case of suspected dengue, the majority (60%) would choose to first seek medical help versus first treating at home, in contrast to 11% in the case of fever. Amongst those who decided to visit a doctor, a suspected dengue infection would prompt them to search medical help earlier than if having only fever (p<0.001). Multivariate analysis modelling showed that the independent factors associated with the intention to firstly visit a doctor versus treating at home in the case of dengue were feeling at risk (OR = 3.29; p = 0.042) and being an adult (as opposed to caring for a child as a parent/guardian; OR = 3.33, p = 0.021), while having had a previous dengue infection (OR = 0.29; p = 0.031) and living in the neighbourhood Caña de Azúcar (OR = 0.28, p = 0.038) were negatively associated with seeking medical care as their first action. CONCLUSION:Knowledge of HSB related to dengue is scarce in the Americas, our study attempts to contribute to a better understanding of HSB in this region. Improving early dengue disease recognition and awareness may enhance prompt attendance to medical care in affected populations and thereby reduce mortality and severity of dengue. Especially for those with a previous dengue infection, efforts have to be made to promote prompt health centre attendance

    Serologic Evidence of West Nile Virus Infection in Horses, Coahuila State, Mexico

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    Serum samples were obtained from 24 horses in the State of Coahuila, Mexico, in December 2002. Antibodies to West Nile virus were detected by epitope-blocking enzyme-linked immunosorbent assay and confirmed by plaque reduction neutralization test in 15 (62.5%) horses. We report the first West Nile virus activity in northern Mexico

    Reduction in the Incidence of Type 2 Diabetes With the Mediterranean Diet: Results of the PREDIMED-Reus nutrition intervention randomized trial

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    OBJECTIVE - To test the effects of two Mediterranean diet (MedDiet) interventions versus a low-fat diet on incidence of diabetes. RESEARCH DESIGN AND METHODS - This was a three-arm randomized trial in 418 nondiabetic subjects aged 55-80 years recruited in one center (PREDIMED-Reus, northeastern Spain) of the Prevención con Dieta Mediterránea [PREDIMED] study, a large nutrition intervention trial for primary cardiovascular prevention in individuals at high cardiovascular risk. Participants were randomly assigned to education on a low-fat diet (control group) or to one of two MedDiets, supplemented with either free virgin olive oil (1 liter/week) or nuts (30 g/day). Diets were ad libitum, and no advice on physical activity was given. The main outcome was diabetes incidence diagnosed by the 2009 American Diabetes Association criteria. RESULTS - After a median follow-up of 4.0 years, diabetes incidence was 10.1% (95% CI 5.1-15.1), 11.0% (5.9 -16.1), and 17.9% (11.4 -24.4) in the MedDiet with olive oil group, the MedDiet with nuts group, and the control group, respectively. Multivariable adjusted hazard ratios of diabetes were 0.49 (0.25- 0.97) and 0.48 (0.24-0.96) in the MedDiet supplemented with olive oil and nuts groups, respectively, compared with the control group. When the two MedDiet groups were pooled and compared with the control group, diabetes incidence was reduced by 52% (27- 86). In all study arms, increased adherence to the MedDiet was inversely associated with diabetes incidence. Diabetes risk reduction occurred in the absence of significant changes in body weight or physical activity. CONCLUSIONS - MedDiets without calorie restriction seem to be effective in the prevention of diabetes in subjects at high cardiovascular risk. © 2011 by the American Diabetes Association.This study was funded, in part, by the Spanish Ministry of Health (Instituto de Salud Carlos III) (projects PI051839, PI070240, PI1001407, G03/140, and RD06/0045), Fondo Europeo de Desarrollo Regional, and the Public Health Division of the Department of Health of the Autonomous Government of Catalonia in collaboration with Merck Sharp & Dohme. The Fundación Patrimonio Comunal Olivarero and Hojiblanca SA (Málaga, Spain), California Walnut Commission (Sacramento, CA), Borges SA (Reus, Spain), and Morella Nuts SA (Reus, Spain) donated the olive oil, walnuts, almonds, and hazelnuts, respectively, used in the study.Peer Reviewe

    Total dairy consumption in relation to overweight and obesity in children and adolescents: A systematic review and meta-analysis

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    A systematic review and meta-analysis of cross-sectional and prospective cohort studies was conducted to assess the associations between total dairy consumption and its different subtypes with the prevalence and incidence of overweight, obesity, and overweight/obesity in children and adolescents. A literature search was conducted in Medline through PUBMED and Cochrane Library databases until October 18, 2021. Articles reporting the risk estimates as odd ratios (OR), risk ratios (RR), or hazard ratios and their corresponding 95% confidence interval (CI) for the association between dairy product consumption and the risk of overweight and/or obesity were included. In the meta-analysis from cross-sectional studies, results showed an inverse association between total dairy consumption and obesity prevalence (OR (95% CI): 0.66 (0.48–0.91). No significant associations were found between milk or yogurt and obesity prevalence risk. Regarding prospective studies, total milk consumption was positively associated with overweight prevalence (OR (95% CI): 1.13 (1.01–1.26)) and incidence (RR (95%CI): 1.17 (1.01–1.35)) risk. Evidence from pooled analysis of cross-sectional studies suggested an inverse association between total dairy consumption and obesity. However, there is limited and no conclusive evidence to confirm an inverse relationship from pooled analysis of prospective studies in children and adolescents
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