583 research outputs found

    Ab-initio investigation of phonon dispersion and anomalies in palladium

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    In recent years, palladium has proven to be a crucial component for devices ranging from nanotube field effect transistors to advanced hydrogen storage devices. In this work, I examine the phonon dispersion of fcc Pd using first principle calculations based on density functional perturbation theory. While several groups in the past have studied the acoustic properties of palladium, this is the first study to reproduce the phonon dispersion and associated anomaly with high accuracy and no adjustable parameters. In particular, I focus on the Kohn anomaly in the [110] direction.Comment: 19 pages, preprint format, 7 figures, added new figures and discussio

    Long-term use of antibiotics and risk of colorectal adenoma

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    Objective—Recent evidence suggests that antibiotic use, which alters the gut microbiome, is associated with an increased risk of colorectal cancer. However, the association between antibiotic use and risk of colorectal adenoma, the precursor for the majority of colorectal cancers, has not been investigated. Design—We prospectively evaluated the association between antibiotic use at age 20–39 and 40–59 (assessed in 2004) and recent antibiotic use (assessed in 2008) with risk of subsequent colorectal adenoma among 16,642 women aged ≄60 enrolled in the Nurses’ Health Study who underwent at least one colonoscopy through 2010. We used multivariate logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Results—We documented 1,195 cases of adenoma. Increasing duration of antibiotic use at age 20–39 (Ptrend=0.002) and 40–59 (Ptrend=0.001) was significantly associated with an increased risk of colorectal adenoma. Compared to non-users, women who used antibiotics for ≄2 months between age 20–39 had a multivariable OR of 1.36 (95% CI: 1.03–1.79). Women who used ≄2 months of antibiotics between age 40–59 had a multivariable OR of 1.69 (95% CI: 1.24–2.31). The associations were similar for low-risk vs. high-risk adenomas (size ≄1 cm, or with tubulovillous/villous histology, or ≄3 detected lesions), but appeared modestly stronger for proximal compared with distal adenomas. In contrast, recent antibiotic use within the past 4 years was not associated with risk of adenoma (Ptrend=0.44). Conclusions—Long-term antibiotic use in early to middle adulthood was associated with increased risk of colorectal adenoma

    Dietary Patterns and Risk of Colorectal Cancer Subtypes Classified by Fusobacterium nucleatum in Tumor Tissue

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    Importance—Fusobacterium nucleatum appears to play a role in colorectal carcinogenesis through suppression of host immune response to tumor. Evidence also suggests that diet influences intestinal F. nucleatum. However, the role of F. nucleatum in mediating the relationship between diet and the risk of colorectal cancer is unknown. Objective—To test the hypothesis that the associations of prudent diets (rich in whole grains and dietary fiber) and Western diets (rich in red and processed meat, refined grains, and desserts) with colorectal cancer risk may differ according to the presence of F. nucleatum in tumor tissue. Design—Prospective cohort study. Setting—The Nurses’ Health Study (1980–2012) and the Health Professionals Follow-up Study (1986–2012). Participants—121,700 US female nurses and 51,529 US male health professionals aged 30 to 55 years and 40 to 75 years, respectively, at enrollment. Exposures—Prudent and Western dietary patterns. Main Outcomes and Measures—Incidence of colorectal carcinoma subclassified by F. nucleatum status in tumor tissue, determined by quantitative polymerase chain reaction. Results—We documented 1,019 incident colon and rectal cancer cases with available F. nucleatum data among predominantly white 137,217 individuals over 26–32 years of follow-up encompassing 3,643,562 person-years. The association of prudent diet with colorectal cancer significantly differed by tissue F. nucleatum status (Pheterogeneity = .01). Prudent diet score was associated with a lower risk of F. nucleatum-positive cancers [Ptrend = .003; multivariable hazard ratio of 0.43 (95% confidence interval 0.25–0.72) for the highest vs. the lowest prudent score quartile], but not with F. nucleatum-negative cancers (Ptrend = .47). Dietary component analyses suggested possible differential associations for the cancer subgroups according to intakes of dietary fiber (Pheterogeneity = .02). There was no significant heterogeneity between the subgroups according to Western dietary pattern scores (Pheterogeneity = .23). Conclusions and Relevance—Prudent diets rich in whole grains and dietary fiber are associated with a lower risk for F. nucleatum-positive colorectal cancer but not F. nucleatum-negative cancer, supporting a potential role for intestinal microbiota in mediating the association between diet and colorectal neoplasms

    Trend in admissions, clinical features and outcome of preeclampsia and eclampsia as seen from the intensive care unit of the Douala General Hospital, Cameroon

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    Introduction: Hypertensive disorders in pregnancy (HDP) are a major cause of maternal morbidity and mortality. We aimed at determining the trends in admission, profiles and outcomes of women admitted for preeclampsia and eclampsia to an intensive care unit (ICU) in Cameroon. Methods: A retrospective study involving 74 women admitted to the ICU of the Douala General Hospital for severe preeclampsia and eclampsia from January 2007 to December 2014. Clinical profiles and outcome data were obtained from patient records. Statistical analysis was performed using SPSS version 20. Results: Of the 74 women admitted to ICU (72.5% for eclampsia), mean age was 30.2years and the majority (90.5%) were aged 20-39 years. While overall trend in admission for HDP increased over the years, mortality remained stable. Mean gestational age (GA) on admission was 34.0 weeks (33.5 for preeclampsia vs 35.4 for eclampsia). Most patients presented with complications of which acute kidney injury was most frequent (66.7%). Visual problems were more common in patients with eclampsia compared to preeclampsia (p=0.01). HELLP syndrome and acute pulmonary oedema (APO) were predominant in patients with preeclampsia, while cerebrovascular accidents (CVA) occurred more in patients with eclampsia. Overall mortality was 24.3%. Presence of APO was associated with mortality in multivariable analysis (O.R.= 0.03, p=0,01). Conclusion: Trends in admission for HDP were increasing with high but stable mortality rate. Patients presented late most of whom with complications. Interventions improving antenatal care services and multidisciplinary management approach may improve maternal outcome in patients with HDP

    Dysferlinopathy in Switzerland: clinical phenotypes and potential founder effects.

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    BACKGROUND: Dysferlin is reduced in patients with limb girdle muscular dystrophy type 2B, Miyoshi myopathy, distal anterior compartment myopathy, and in certain Ethnic clusters. METHODS: We evaluated clinical and genetic patient data from three different Swiss Neuromuscular Centers. RESULTS: Thirteen patients from 6 non-related families were included. Age of onset was 18.8 ± 4.3 years. In all patients, diallelic disease-causing mutations were identified in the DYSF gene. Nine patients from 3 non-related families from Central Switzerland carried the identical homozygous mutation, c.3031 + 2 T>C. A possible founder effect was confirmed by haplotype analysis. Three patients from two different families carried the heterozygous mutation, c.1064_1065delAA. Two novel mutations were identified (c.2869 C>T (p.Gln957Stop), c.5928 G>A (p.Trp1976Stop)). CONCLUSIONS: Our study confirms the phenotypic heterogeneity associated with DYSF mutations. Two mutations (c.3031 + 2 T>C, c.1064_1065delAA) appear common in Switzerland. Haplotype analysis performed on one case (c. 3031 + 2 T>C) suggested a possible founder effect

    Evaluation of CSF and plasma biomarkers of brain melanocortin activity in response to caloric restriction in humans

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    The melanocortin neuronal system, which consists of hypothalamic proopiomelanocortin (POMC) and agouti-related protein (AgRP) neurons, is a leptin target that regulates energy balance and metabolism, but studies in humans are limited by a lack of reliable biomarkers to assess brain melanocortin activity. The objective of this study was to measure the POMC prohormone and its processed peptide, ÎČ-endorphin (ÎČ-EP), in cerebrospinal fluid (CSF) and AgRP in CSF and plasma after calorie restriction to validate their utility as biomarkers of brain melanocortin activity. CSF and plasma were obtained from 10 lean and obese subjects after fasting (40 h) and refeeding (24 h), and from 8 obese subjects before and after 6 wk of dieting (800 kcal/day) to assess changes in neuropeptide and hormone levels. After fasting, plasma leptin decreased to 35%, and AgRP increased to 153% of baseline. During refeeding, AgRP declined as leptin increased; CSF ÎČ-EP increased, but POMC did not change. Relative changes in plasma and CSF leptin were blunted in obese subjects. After dieting, plasma and CSF leptin decreased to 46% and 70% of baseline, CSF POMC and ÎČ-EP decreased, and plasma AgRP increased. At baseline, AgRP correlated negatively with insulin and homeostasis model assessment (HOMA-IR), and positively with the Matsuda index. Thus, following chronic calorie restriction, POMC and ÎČ-EP declined in CSF, whereas acutely, only ÎČ-EP changed. Plasma AgRP, however, increased after both acute and chronic calorie restriction. These results support the use of CSF POMC and plasma AgRP as biomarkers of hypothalamic melanocortin activity and provide evidence linking AgRP to insulin sensitivity

    Effets de l’amprolin-300 Ws sur quelques paramùtres de croissance et de reproduction chez le lapin mñle (Oryctolagus cuniculus)

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    Objectif : L’objectif de la prĂ©sente Ă©tude a Ă©tĂ© de rechercher les effets de l’Amprolin-300, un anticoccidien largement utilisĂ© en mĂ©decine vĂ©tĂ©rinaire, sur quelques paramĂštres de croissance et de reproduction chez le lapin mĂąle de race locale. MĂ©thodologie et rĂ©sultats : Vingt-quatre (24) lapins ĂągĂ©s de 5 mois environ et pesant entre 2,01 et 2,78 kg ont Ă©tĂ© rĂ©partis en 4 lots comparables de 6 lapins chacun. Ils ont Ă©tĂ© traitĂ©s pendant 60 jours avec diffĂ©rentes doses d’Amprolin-300 ws via l’eau de boisson : 0 ; 30 ; 60 et 110 mg/kg de poids corporel. Les rĂ©sultats obtenus ont rĂ©vĂ©lĂ© que la consommation d’eau a significativement (p<0,05) diminuĂ© chez les lapins traitĂ©s aux doses 60 et 110 mg/kg de poids corporel par rapport aux tĂ©moins. Le gain de poids et le gain moyen quotidien ont diminuĂ© de maniĂšre significative (p<0,05) chez les animaux traitĂ©s aux doses 30 et 60 mg/kg de poids corporel par rapport aux animaux du lot tĂ©moin. Par contre, l’indice de consommation a diminuĂ© de façon significative (p<0,05) chez les animaux tĂ©moins et chez ceux qui ont ingĂ©rĂ© la plus forte dose d’Amprolin-300 ws (110 mg/kg de poids corporel) comparĂ© aux lapins traitĂ©s avec les doses 30 et 60 mg/kg respectivement. Le pH de la semence a significativement (p<0,05) augmentĂ© chez les mĂąles traitĂ©s aux doses 30 et 60 mg/kg de poids corporel par rapport Aux mĂąles du lot tĂ©moin. La motilitĂ© individuelle et la concentration des spermatozoĂŻdes ont diminuĂ© de maniĂšre significative (p<0,05) chez les lapins qui ont ingĂ©rĂ© la plus forte dose d’anticoccidien par rapport aux lapins tĂ©moins. Conclusion et application des rĂ©sultats : Ainsi, Ă  la dose de 110 mg/kg de poids corporel, l’Amprolin-300 ws a rĂ©duit la consommation alimentaire, le gain de poids, le gain moyen quotidien, le poids spĂ©cifique et le pH de la semence. Cette dose a Ă©galement inhibĂ© la spermatogenĂšse et rĂ©duit le pourcentage de spermatozoĂŻdes mobiles. Son usage devrait donc ĂȘtre rĂšglementĂ©.Mots clĂ©s : Amprolin-300 ws, lapin mĂąle, production et fertilitĂ©.Objective: In this study, the effects of Amprolin-300 ws, an anticoccidiostat abundantly used in veterinary medicine, on some growth and reproductive parameters in male rabbits were investigated. Methodology and results: Twenty four (24) rabbits aged 5 months and weighing between 2.01 and 2.78 kg were divided into 4 comparable groups of six rabbits each and treated for 60 days with different doses of Amprolin-300 ws from drinking water: 0, 30, 60 and 110 g/kg of body weight. The results showed that water consumption was significantly (p<0.05) decreased in rabbits treated with 60 and 110 mg/kg of body weight of Amprolin-300 compared to control rabbits. Body weight gain and average daily gain decreased significantly (p<0.05) in animals treated with 30 and 60 mg/kg of body weight compared to control rabbits. On the other hand, feed efficiency decreased significantly (p<0.05) in control animals and those who ingested the highest dose (110 mg/kg of body weight) compared to rabbits treated with 30 and 60 mg/kg of body weight respectively. The pH of semen increased significantly (p<0.05) in animals treated with 30 and 60 mg/kg of body weight compared to control animals. Individual motility and sperm concentration decreased significantly (p<0.05) in rabbits who received the highest dose of Amprolin-300 compared to control rabbits. Conclusion and application of results: Thus, at the dose of 110 mg/kg body weight, Amprolinws-300 reduced in male rabbit, food consumption, body and average daily weight gain, specific weight and pH of semen. It inhibited spermatogenesis and reduced sperm mobility. Therefore its use should be regulated

    Gravitational lensing on the Cosmic Microwave Background by gravity waves

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    We study the effect of a stochastic background of gravitational waves on the gravitational lensing of the Cosmic Microwave Background (CMB) radiation. It has been shown that matter density inhomogeneities produce a smoothing of the acoustic peaks in the angular power spectrum of the CMB anisotropies. A gravitational wave background gives rise to an additional smoothing of the spectrum. For the most simple case of a gravitational wave background arising during a period of inflation, the effect results to be three to four orders of magnitude smaller than its scalar counterpart, and is thus undetectable. It could play a more relevant role in models where a larger background of gravitational waves is produced.Comment: 6 pages, RevTeX file, 1 figur
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