2,017 research outputs found

    Hillslopes record the growth and decay of landscapes

    Get PDF
    Earth's surface archives the combined history of tectonics and erosion, which tend to roughen landscapes, and sediment transport and deposition, which smooth them. We analyzed hillslope morphology in the tectonically active Dragon’s Back Pressure Ridge in California, United States, to assess whether tectonic uplift history can be reconstructed using measurable attributes of hillslope features within landscapes. Hilltop curvature and hillslope relief mirror measured rates of vertical displacement caused by tectonic forcing, and their relationships are consistent with those expected when idealizing hillslope transport as a nonlinear diffusion process. Hilltop curvature lags behind relief in its response to changing erosion rates, allowing growing landscapes to be distinguished from decaying landscapes. Numerical modeling demonstrates that hillslope morphology may be used to infer changes in tectonic rates

    Hemostatic complications associated with ventricular assist devices.

    Get PDF
    Hemostatic complications are common in patients with ventricular assist devices. The pathophysiologic mechanisms that lead to dysregulated hemostasis involve complex interactions between device surface, sheer stress, and blood flow. These factors lead to various manifestations that require a thorough understanding of the interplay among platelets, coagulation factors, and red cells. In this article, we review the pathophysiology of hematologic complications (bleeding, acquired von Willebrand disease, heparin-induced thrombocytopenia, hemolysis, stroke and pump thrombosis), the clinical manifestations, and the management of each. We summarize the evidence available for management of these entities and provide a pragmatic clinical review

    Global projection of lead-zinc supply from known resources

    Full text link
    © 2018 by the authors. Lead and zinc are used extensively in the construction and automotive industries, and require sustainable supply. In order to understand the future availability of lead and zinc, we have projected global supplies on a country-by-country basis from a detailed global assessment of mineral resources for 2013. The model GeRS-DeMo was used to create projections of lead and zinc production from ores, as well as recycling for lead. Our modelling suggests that lead and zinc production from known resources is set to peak within 15 years (lead 2025, zinc 2031). For lead, the total supply declines relatively slowly post peak due to recycling. If additional resources are found, these peaks would shift further into the future. These results suggest that lead and zinc consumers will need to plan for the future, potentially by: seeking alternative supplies (e.g., mine tailings, smelter/refinery slags); obtaining additional value from critical metals contained in lead-zinc ore deposits to counter lower grade ores; identifying potential substitutes; redesigning their products; or by contributing to the development of recycling industries

    Establishment of novel neuroendocrine carcinoma patient-derived xenograft models for receptor peptide-targeted therapy

    Get PDF
    Gastroenteropancreatic neuroendocrine neoplasms (GEP NENs) are rare cancers consisting of neuroendocrine carcinomas (NECs) and neuroendocrine tumors (NETs), which have been increasing in incidence in recent years. Few cell lines and pre-clinical models exist for studying GEP NECs and NETs, limiting the ability to discover novel imaging and treatment modalities. To address this gap, we isolated tumor cells from cryopreserved patient GEP NECs and NETs and injected them into the flanks of immunocompromised mice to establish patient-derived xenograft (PDX) models. Two of six mice developed tumors (NEC913 and NEC1452). Over 80% of NEC913 and NEC1452 tumor cells stained positive for Ki67. NEC913 PDX tumors expressed neuroendocrine markers such as chromogranin A (CgA), synaptophysin (SYP), and somatostatin receptor-2 (SSTR2), whereas NEC1452 PDX tumors did not express SSTR2. Exome sequencing revealed loss o

    Hypermethioninaemia due to methionine adenosyltransferase I/III (MAT I/III) deficiency: diagnosis in an expanded neonatal screening programme

    Get PDF
    The Expanded Newborn Screening Program (MS/MS) in the region of Galicia (NW Spain) was initiated in 2000 and includes the measurement of methionine levels in dried blood spots. Between June 2000 and June 2007, 140 818 newborns were analysed, and six cases of persistent hypermethioninaemia were detected: one homocystinuria due to cystathionine β-synthase (CβS) deficiency, and five methionine adenosyltransferase I/III (MAT I/III) deficiencies. The five cases of MAT I/III deficiency represent an incidence of 1/28 163 newborns. In these five patients, methionine levels in dried blood spots ranged from 50 to 147 μmol/L. At confirmation of the persistence of the hypermethioninaemia in a subsequent plasma sample, plasma methionine concentrations were moderately elevated in 4 of the 5 patients (mean 256 μmol/L), while total homocysteine (tHcy) was normal; the remaining patient showed plasma methionine of 573 μmol/L and tHcy of 22.8 μmol/L. All five patients were heterozygous for the same dominant mutation, R264H in the MAT1A gene. With a diet not exceeding recommended protein requirements for their age, all patients maintained methionine levels below 300 μmol/L. Currently, with a mean of 2.5 years since diagnosis, the patients are asymptomatic and show developmental quotients within the normal range. Our results show a rather high frequency of hypermethioninaemia due to MAT I/III deficiency in the Galician neonatal population, indicating a need for further studies to evaluate the impact of persistent isolated hypermethioninaemia in neonatal screening programmes

    Employees’ feelings about more meetings: An overt analysis and recommendations for improving meetings

    Get PDF
    Purpose – The purpose of this paper is to identify how employees feel about having more meetings and what can be done to improve employees’ feelings about their work meetings. Design/methodology/approach – Data were obtained from three samples of working adults. The first was a convenience sample recruited by undergraduate students (n = 120), the second was a stratified random sample from a metropolitan area in the southern USA (n = 126), and the third was an internet-based panel sample (n = 402). Constant comparative analysis of responses to open-ended questions was used to investigate the overarching research questions. Findings – It is found that employees enjoy meetings when they have a clear objective, and when important relevant information is shared. Consistent with conservation of resources theory, most employees are unhappy with meetings when they reduce their work-related resources (e.g. meetings constrain their time, lack structure and are unproductive). Practical implications – The data suggest that meetings appear to be both resource-draining and resource-supplying activities in the workplace. Researchers and managers should consider overtly asking about how people feel about meetings, as a means of identifying areas for future research inquiry and targets for improvement in the workplace generally. Originality/value – The paper describes one of the few studies on meetings that ask the participants overtly what their feelings are regarding their workplace meetings. Additionally, the paper illustrates the usefulness of qualitative data analysis as a means for further understanding workplace activities viewing respondents as informants. Keywords United States of America, Employees behaviour, Employees attitudes, Employees participation, Meetings, Meeting demands, Qualitative research, Thematic analysi

    Environmental influences on familial discordance of phenotype in people with homocystinuria: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Non-heritable factors may have an influence on the clinical expression of monogenic inherited metabolic diseases.</p> <p>Case presentation</p> <p>This is a case report of a man whose mother had been diagnosed late in childhood with pyridoxine responsive homocystinuria with lens dislocation and neurodevelopmental delay. These severe complications were not observed in her son who was pyridoxine unresponsive but who had been treated appropriately since early infancy.</p> <p>Conclusion</p> <p>The phenotype of people with homocystinuria can be discordant within a family, with variability in metabolic and clinical expression depending upon both the genotype and therapeutic interventions. Offspring of people with homocystinuria should be screened in early infancy and, if positive, treated appropriately whether they have pyridoxine responsive or unresponsive disease.</p
    • …
    corecore