308 research outputs found

    Electron correlations for ground state properties of group IV semiconductors

    Full text link
    Valence energies for crystalline C, Si, Ge, and Sn with diamond structure have been determined using an ab-initio approach based on information from cluster calculations. Correlation contributions, in particular, have been evaluated in the coupled electron pair approximation (CEPA), by means of increments obtained for localized bond orbitals and for pairs and triples of such bonds. Combining these results with corresponding Hartree-Fock (HF) data, we recover about 95 % of the experimental cohesive energies. Lattice constants are overestimated at the HF level by about 1.5 %; correlation effects reduce these deviations to values which are within the error bounds of this method. A similar behavior is found for the bulk modulus: the HF values which are significantly too high are reduced by correlation effects to about 97 % of the experimental values.Comment: 22 pages, latex, 2 figure

    Effective tax levels using the Devereux/Griffith methodology. Project for the EU Commission TAXUD/2013/CC/120: Final report

    Full text link
    [Introduction] This 2016 report of the project TAXUD/2013/CC/120 presents estimates of the effective tax rates on investment in the EU member states, FYROM and Turkey as well as Norway, Switzerland, Canada, Japan and the United States. The work presented in this report updates for the year 2016 the analyses of the previous projects within the former Framework Contract TAXUD/2008/CC/099 and the current Framework Contract TAXUD/2013/CC/120. Following the methodology used in previous work, we apply the Devereux and Griffith framework to compute effective tax levels. The report considers primarily taxes on corporations in each country, but also includes analyses of personal taxes on investment and saving. It also considers both cross-border investment and investment by small and medium sized enterprises (SME). Background information to the applied model can be found in Devereux and Griffith (1999, 2003), Schreiber et al. (2002) and European Commission (2008, p. 3-54). In addition, the European Commission has recently published studies on the specific impact of interest and inflation rates, tax planning and the debt/equity bias on forward-looking effective tax rates. This report is organized as follows. Section A introduces the tax parameters for the period 1998 - 2016 covered by this report. These tax parameters form the basis of the computations of effective tax rates. Section B provides worked examples for several countries for a better understanding of the model. Section C then provides detailed results for domestic investment in all countries covered in this report. In addition to results focusing on the corporate level, this report comprehensively includes the analysis of personal taxes on investment and saving at the shareholder level for three different types of shareholders when calculating effective tax rates on domestic investment. Section D presents estimates for effective tax burdens of cross-border investment if all countries were either locations of investment or locations of the investor. Finally, Section E provides effective tax burdens of SMEs in selected countries. Please note that all results presented in this report refer to the legal situation as of 1 July 2016

    Polymorphic residues in rice NLRs expand binding and response to effectors of the blast pathogen

    Get PDF
    Accelerated adaptive evolution is a hallmark of plant-pathogen interactions. Plant intracellular immune receptors (NLRs) often occur as allelic series with differential pathogen specificities. The determinants of this specificity remain largely unknown. Here, we unravelled the biophysical and structural basis of expanded specificity in the allelic rice NLR Pik, which responds to the effector AVR-Pik from the rice blast pathogen Magnaporthe oryzae. Rice plants expressing the Pikm allele resist infection by blast strains expressing any of three AVR-Pik effector variants, whereas those expressing Pikp only respond to one. Unlike Pikp, the integrated heavy metal-associated (HMA) domain of Pikm binds with high affinity to each of the three recognized effector variants, and variation at binding interfaces between effectors and Pikp-HMA or Pikm-HMA domains encodes specificity. By understanding how co-evolution has shaped the response profile of an allelic NLR, we highlight how natural selection drove the emergence of new receptor specificities. This work has implications for the engineering of NLRs with improved utility in agriculture

    Isotopic evidence of high reliance on plant food among Later Stone Age hunter-gatherers at Taforalt, Morocco

    Get PDF
    The transition from hunting-gathering to agriculture stands as one of the most important dietary revolutions in human history. Yet, due to a scarcity of well-preserved human remains from Pleistocene sites, little is known about the dietary practices of pre-agricultural human groups. Here we present the isotopic evidence of pronounced plant reliance among Late Stone Age hunter-gatherers from North Africa (15,000–13,000 cal BP), predating the advent of agriculture by several millennia. Employing a comprehensive multi-isotopic approach, we conducted zinc (δ66Zn) and strontium (87Sr/86Sr) analysis on dental enamel, bulk carbon (δ13C) and nitrogen (δ15N) and sulfur (δ34S) isotope analysis on dentin and bone collagen, and single amino acid analysis on human and faunal remains from Taforalt (Morocco). Our results unequivocally demonstrate a substantial plant-based component in the diets of these hunter-gatherers. This distinct dietary pattern challenges the prevailing notion of high reliance on animal proteins among pre-agricultural human groups. It also raises intriguing questions surrounding the absence of agricultural development in North Africa during the early Holocene. This study underscores the importance of investigating dietary practices during the transition to agriculture and provides insights into the complexities of human subsistence strategies across different regions. © The Author(s) 2024

    Design aspects for prognostic factor studies

    Get PDF
    Prognostic research is clinically relevant and ultimately facilitates stratified medicine. However, its quality and output are limited. More guidance is needed to improve understanding and thus quality. On behalf of the topic group 'TG5: study design' of the STRATOS initiative and for the general readership, this article describes key concepts and issues for prognostic factor studies, a sub-area of prognosis research. After providing a general overview on prognosis research, the article covers aspects such as aims, estimands and designs of prognostic factor studies, highlighting standards and current practice. Focusing on prognostic factor studies that assess a single factor at a time and a binary outcome, this article is complemented by a glossary of terms and a list of general aspects to consider in prognostic factor studies

    Case Report: Full recovery in severe ParvovirusB19 myocarditis with DCM phenotype: the impact of rASD and PAB

    Get PDF
    BackgroundThe incidence of parvovirus B19 (B19 V)-associated myocarditis progressing to dilated cardiomyopathy (DCM) is on the rise. We hypothesize that a comprehensive treatment regimen enables cardiac regeneration in young patients with life-threatening B19 V myocarditis.MethodsFour patients with clinical and imaging evidence of DCM were referred due to suspected myocarditis. An endomyocardial biopsy (EMB) confirmed the diagnosis. The diastolic dysfunction associated with heart failure and reduced left ventricular ejection fraction (HFrEF) was established invasively. Before surgical pulmonary artery banding (PAB), a transcatheter procedure was performed to create a restrictive atrial defect (rASD).ResultsThe drug-treated patients (ages 15–26 months) had a mean LV-EF of 22.5% (20%–25%), a left ventricular end-diastolic diameter (LVEDD) of 49 (45–51) mm (Z-score >5), and elevated LVED pressures (>18 mmHg). EMB revealed B19V-associated acute/subacute or chronic active myocarditis with characteristics of DCM. Drug therapy, including immunoglobulins and creating a rASD, resulted in clinical improvement and enhanced right ventricular function. However, LV enlargement and dysfunction persisted. Four weeks after surgical PAB, all patients showed improvement and were discharged home. The pressure gradient across the PAB ranged from 40 to 45 mmHg, and LVEDD decreased to a mean z-score of +3.5. Within three to six months, LVEDD normalized, and LV-EF increased to a mean of 63% (range: 57%–68%). Clinical and cardiac improvements were sustained over a median follow-up of 7.5 years.ConclusionA holistic treatment approach allows functional regeneration in B19 V myocarditis with obvious end-stage DCM. Restrictive ASD creation is required before surgical PAB when HFrEF is associated with a diastolic dysfunction component

    Effect of photon flux densities on regulation of carotenogenesis and cell viability of Haematococcus pluvialis (Chlorophyceae)

    Get PDF
    The green alga Haematococcus pluvialis produces large amounts of the pink carotenoid astaxanthin under high photon flux density (PFD) and other oxidative stress conditions. However, the regulation and physiological role of carotenogenesis leading to astaxanthin formation is not well understood. Comparative transcriptional expression of five carotenoid genes along with growth and pigment composition as a function of PFD was studied using a wild-type and an astaxanthin-overproduction mutant of H. pluvialis NIES144. The results indicate that astaxanthin biosynthesis was mainly under transcriptional control of the gene encoding carotenoid hydroxylase, and to a lesser extent, the genes encoding isopentenyl isomerase and phytoene desaturase, and to the least extent, the genes encoding phytoene synthase and carotenoid oxygenase. The expression of a plastid terminal oxidase (PTOX) gene ptox2 underwent transient up-regulation under elevated PFDs, suggesting that PTOX may be functionally coupled with phytoene desaturase through the plastoquinone pool and may play a role in reducing redox-potential-dependent and oxygen-concentration-dependent formation of reactive oxygen species in the chloroplast. Over-expression of both the carotenogenic and PTOX genes confers to the astaxanthin-overproduction mutant more effective photoprotective capability than that of the wild type under photooxidative stress

    TIMP-2 Fusion Protein with Human Serum Albumin Potentiates Anti-Angiogenesis-Mediated Inhibition of Tumor Growth by Suppressing MMP-2 Expression

    Get PDF
    TIMP-2 protein has been intensively studied as a promising anticancer candidate agent, but the in vivo mechanism underlying its anticancer effect has not been clearly elucidated by previous works. In this study, we investigated the mechanism underlying the anti-tumor effects of a TIMP-2 fusion protein conjugated with human serum albumin (HSA/TIMP-2). Systemic administration of HSA/TIMP-2 effectively inhibited tumor growth at a minimum effective dose of 60 mg/kg. The suppressive effect of HSA/TIMP-2 was accompanied by a marked reduction of in vivo vascularization. The anti-angiogenic activity of HSA/TIMP-2 was directly confirmed by CAM assays. In HSA/TIMP-2-treated tumor tissues, MMP-2 expression was profoundly decreased without a change in MT1-MMP expression of PECAM-1-positive cells. MMP-2 mRNA was also decreased by HSA/TIMP-2 treatment of human umbilical vein endothelial cells. Zymographic analysis showed that HSA/TIMP-2 substantially decreased extracellular pro-MMP-2 activity (94–99% reduction) and moderately decreased active MMP-2 activity (10–24% reduction), suggesting MT1-MMP-independent MMP-2 modulation. Furthermore, HSA/TIMP-2 had no effect on in vitro active MMP-2 activity and in vivo MMP-2 activity. These studies show that HSA/TIMP-2 potentiates anti-angiogenic activity by modulating MMP-2 expression, but not MMP-2 activity, to subsequently suppress tumor growth, suggesting an important role for MMP-2 expression rather than MMP-2 activity in anti-angiogenesis

    Methylseleninic acid promotes antitumour effects via nuclear FOXO3a translocation through Akt inhibition

    Get PDF
    Selenium supplement has been shown in clinical trials to reduce the risk of different cancers including lung carcinoma. Previous studies reported that the antiproliferative and pro-apoptotic activities of methylseleninic acid (MSA) in cancer cells could be mediated by inhibition of the PI3K pathway. A better understanding of the downstream cellular targets of MSA will provide information on its mechanism of action and will help to optimize its use in combination therapies with PI3K inhibitors. For this study, the effects of MSA on viability, cell cycle, metabolism, apoptosis, protein and mRNA expression, and reactive oxygen species production were analysed in A549 cells. FOXO3a subcellular localization was examined in A549 cells and in stably transfected human osteosarcoma U2foxRELOC cells. Our results demonstrate that MSA induces FOXO3a nuclear translocation in A549 cells and in U2OS cells that stably express GFP-FOXO3a. Interestingly, sodium selenite, another selenium compound, did not induce any significant effects on FOXO3a translocation despite inducing apoptosis. Single strand break of DNA, disruption of tumour cell metabolic adaptations, decrease in ROS production, and cell cycle arrest in G1 accompanied by induction of apoptosis are late events occurring after 24h of MSA treatment in A549 cells. Our findings suggest that FOXO3a is a relevant mediator of the antiproliferative effects of MSA. This new evidence on the mechanistic action of MSA can open new avenues in exploiting its antitumour properties and in the optimal design of novel combination therapies. We present MSA as a promising chemotherapeutic agent with synergistic antiproliferative effects with cisplatin. (C) 2015 Elsevier Ltd. All rights reserved.Ministerio de Ciencia e Innovacion, Spain [SAF2011-25726]; Agencia de Gestio d'Ajuts Universitaris i de Recerca (AGAUR)-Generalitat de Catalunya [2014SGR1017]; Ministerio de Economia y Competitividad, Spain [SAF2014-56059-R]; Fundacao para a Ciencia e a Tecnologia (FCT) Research Center [UID/BIM/04773/2013CBMR 1334]; National Institute of Health, USA [1R01CA118434-01A2, 1P01CA163223-01A1]; National Science Foundation, USA [EPS-0447479]; FCT [SFRH/BPD/84634/2012]; prize ICREA Academia for excellence in research; ICREA Foundation-Generalitat de Cataluny
    corecore