2,557 research outputs found

    Simple Metals at High Pressure

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    In this lecture we review high-pressure phase transition sequences exhibited by simple elements, looking at the examples of the main group I, II, IV, V, and VI elements. General trends are established by analyzing the changes in coordination number on compression. Experimentally found phase transitions and crystal structures are discussed with a brief description of the present theoretical picture.Comment: 22 pages, 4 figures, lecture notes for the lecture given at the Erice course on High-Pressure Crystallography in June 2009, Sicily, Ital

    Intraseasonal Dynamics and Dominant Sequences in H3N2 Influenza

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    Long-term influenza evolution has been well studied, but the patterns of sequence diversity within seasons are less clear. H3N2 influenza genomes sampled from New York State over ten years indicated intraseasonal changes in evolutionary dynamics. Using the mean Hamming distance of a set of amino acid or nucleotide sequences as an indicator of its diversity, we found that influenza sequence diversity was significantly higher during the early epidemic period than later in the influenza season. Diversity was lowest during the peak of the epidemic, most likely due to the high prevalence of a single dominant amino acid sequence or very few dominant sequences during the peak epidemic period, corresponding with rapid expansion of the viral population. The frequency and duration of dominant sequences varied by influenza protein, but all proteins had an abundance of one distinct sequence during the peak epidemic period. In New York State from 1995 to 2005, high sequence diversity during the early epidemic suggested that seasonal antigenic drift could have occurred primarily in this period, followed by a clonal expansion of typically one clade during the peak of the epidemic, possibly indicating a shift to neutral drift or purifying selection

    The influence of C3 and C4 vegetation on soil organic matter dynamics in contrasting semi-natural tropical ecosystems

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    Variations in the carbon isotopic composition of soil organic matter (SOM) in bulk and fractionated samples were used to assess the influence of C3 and C4 vegetation on SOM dynamics in semi-natural tropical ecosystems sampled along a precipitation gradient in West Africa. Differential patterns in SOM dynamics in C3/C4 mixed ecosystems occurred at various spatial scales. Relative changes in C=N ratios between two contrasting SOM fractions were used to evaluate potential site-scale differences in SOM dynamics between C3- and C4-dominated locations. These differences were strongly controlled by soil texture across the precipitation gradient, with a function driven by bulk 13C and sand content explaining 0.63 of the observed variability. The variation of 13C with soil depth indicated a greater accumulation of C3-derived carbon with increasing precipitation, with this trend also being strongly dependant on soil characteristics. The influence of vegetation thickening on SOM dynamics was also assessed in two adjacent, but structurally contrasting, transitional ecosystems occurring on comparable soils to minimise the confounding effects posed by climatic and edaphic factors. Radiocarbon analyses of sand-size aggregates yielded relatively short mean residence times ( ) even in deep soil layers, while the most stable SOM fraction associated with silt and clay exhibited shorter in the savanna woodland than in the neighbouring forest stand. These results, together with the vertical variation observed in 13C values, strongly suggest that both ecosystems are undergoing a rapid transition towards denser closed canopy formations.However, vegetation thickening varied in intensity at each site and exerted contrasting effects on SOM dynamics. Thisstudy shows that the interdependence between biotic and abiotic factors ultimately determine whether SOM dynamics of C3- and C4-derived vegetation are at variance in ecosystems where both vegetation types coexist. The results highlight the far-reaching implications that vegetation thickening may have for the stability of deep SOM. © 2015, Copernicus Publications

    A case of life-threatening post-operative diffuse alveolar hemorrhage in patient with recent chemotherapy -A case report-

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    A 53-year-old woman who had undergone total gastrectomy and received adjuvant chemotherapy two months ago underwent adhesiolysis of the small bowel. She presented with sudden desaturation and dyspnea of unknown etiology at postanesthetic care unit. Following ET intubation, the endotracheal tube suction revealed massive hemoptysis. Bilateral lung infiltrated on her chest radiograph and bronchofibroscopic examination disclosed a diffuse hemorrhage on both lung fields without bleeding focus. These findings were consistent with diffuse alveolar hemorrhage (DAH) syndrome. As per our knowledge and search, this is the first reported case of DAH that occurred during the recovery period immediately after general anesthesia. DAH is known to have a high mortality rate and an early detection followed by adequate treatment is essential

    Impaired metabolism in donor kidney grafts after steroid pretreatment

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    We recently showed in a randomized control trial that steroid pretreatment of the deceased organ donor suppressed inflammation in the transplant organ but did not reduce the rate or duration of delayed graft function (DGF). This study sought to elucidate such of those factors that caused DGF in the steroid-treated subjects. Genome-wide gene expression profiles were used from 20 steroid-pretreated donor-organs and were analyzed on the level of regulatory protein protein interaction networks. Significance analysis of microarrays (SAM) yielded 63 significantly down-regulated sequences associated with DGF that could be functionally categorized according to Protein ANalysis THrough Evolutionary Relationships ontologies into two main biologic processes: transport (P < 0.001) and metabolism (P < 0.001). The identified genes suggest hypoxia as the cause of DGF, which cannot be counterbalanced by steroid treatment. Our data showed that molecular pathways affected by ischemia such as transport and metabolism are associated with DGF. Potential interventional targeted therapy based on these findings includes peroxisome proliferator-activated receptor agonists or caspase inhibitors

    A Risk Score to Predict Type 2 Diabetes Mellitus in an Elderly Spanish Mediterranean Population at High Cardiovascular Risk

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    Abstract Introduction: To develop and test a diabetes risk score to predict incident diabetes in an elderly Spanish Mediterranean population at high cardiovascular risk. Materials and Methods: A diabetes risk score was derived from a subset of 1381 nondiabetic individuals from three centres of the PREDIMED study (derivation sample). Multivariate Cox regression model ß-coefficients were used to weigh each risk factor. PREDIMED-personal Score included body-mass-index, smoking status, family history of type 2 diabetes, alcohol consumption and hypertension as categorical variables; PREDIMED-clinical Score included also high blood glucose. We tested the predictive capability of these scores in the DE-PLAN-CAT cohort (validation sample). The discrimination of Finnish Diabetes Risk Score (FINDRISC), German Diabetes Risk Score (GDRS) and our scores was assessed with the area under curve (AUC). Results: The PREDIMED-clinical Score varied from 0 to 14 points. In the subset of the PREDIMED study, 155 individuals developed diabetes during the 4.75-years follow-up. The PREDIMED-clinical score at a cutoff of $6 had sensitivity of 72.2%, and specificity of 72.5%, whereas AUC was 0.78. The AUC of the PREDIMED-clinical Score was 0.66 in the validation sample (sensitivity = 85.4%; specificity = 26.6%), and was significantly higher than the FINDRISC and the GDRS in both the derivation and validation samples. Discussion: We identified classical risk factors for diabetes and developed the PREDIMED-clinical Score to determine those individuals at high risk of developing diabetes in elderly individuals at high cardiovascular risk. The predictive capability of the PREDIMED-clinical Score was significantly higher than the FINDRISC and GDRS, and also used fewer items in the questionnaire

    Stereotactic Body Radiotherapy for Isolated Para-aortic Lymph Node Recurrence after Curative Resection in Gastric Cancer

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    The aim of this study was to investigate whether stereotactic body radiotherapy (SBRT) can salvage gastric cancer patients with para-aortic lymph node (PALN) recurrence. From January 2003 to December 2006, 7 patients were treated for isolated PALN recurrence from gastric cancer after curative resection. Follow up durations ranged from 19 to 33 months (median; 26 months), and SBRT doses from 45 Gy to 51 Gy (median 48 Gy) in 3 fractions. Disease progression-free and overall survivals and toxicities were recorded. Response to treatment was assessed by computed tomography. Final patient outcomes were as follows: 2 were alive without evidence of disease, 3 remained alive with disease, and 2 patients died of disease. Five of 7 patients showed complete response and 2 patients partial response between 3 and 11 months after SBRT. Three-year overall and disease progression-free survival rates post-SBRT were 43% and 29%, respectively. No severe complication was detected during follow-up. Selected patients with isolated PALN recurrence can be salvaged by SBRT without severe complications
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