1,889 research outputs found

    The role of SPP/SPPL intramembrane proteases in membrane protein homeostasis

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    Signal peptide peptidase (SPP) and the four SPP-like proteases SPPL2a, SPPL2b, SPPL2c and SPPL3 constitute a family of aspartyl intramembrane proteases with homology to presenilins. The different members reside in distinct cellular localisations within the secretory pathway and the endo-lysosomal system. Despite individual cleavage characteristics, they all cleave single-span transmembrane proteins with a type II orientation exhibiting a cytosolic N-terminus. Though the identification of substrates is not complete, SPP/SPPL-mediated proteolysis appears to be rather selective. Therefore, according to our current understanding cleavage by SPP/SPPL proteases rather seems to serve a regulatory function than being a bulk proteolytic pathway. In the present review, we will summarise our state of knowledge on SPP/SPPL proteases and in particular highlight recently identified substrates and the functional and/or (patho)-physiological implications of these cleavage events. Based on this, we aim to provide an overview of the current open questions in the field. These are connected to the regulation of these proteases at the cellular level but also in context of disease and patho-physiological processes. Furthermore, the interplay with other proteostatic systems capable of degrading membrane proteins is beginning to emerge

    TAGS-related indium compounds and their thermoelectric properties – the solid solution series (GeTe)_xAgIn_ySb_(1-y)Te_2 (x = 1–12; y = 0.5 and 1)

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    Various members of the solid solution series (GeTe)_xAgIn_ySb_(1−y)Te_2 can be obtained by quenching high-temperature phases (x = 12 for y = 1 and x > 5 for y = 0.5). In contrast, high-temperature and high-pressure conditions (2.5 GPa, 350 °C) are required for the synthesis of members with In contents >3.6 atom% (such as x 5 adopt the α-GeTe structure type (3 + 3 coordination). Thus, in all samples investigated, 3 or 4 cations are disordered at one Wyckoff position. The quenched high-temperature or high-pressure phases, respectively, are almost homogeneous. Their powder X-ray diffraction patterns suggest pure phases; yet, high-resolution electron microscopy occasionally reveals a very small extent of nanoscopic precipitates as well as dislocations and twinning. (GeTe)_(5.5)AgIn_(0.5)Sb_(0.5)Te_2 shows a maximal ZT value of 0.75 even when (partial) decomposition into the TAGS material (GeTe)_(11)AgSbTe_2 and chalcopyrite-type AgInTe_2 has occurred at 300 °C. (GeTe)_(5.5)AgInTe_2 prepared under high-pressure conditions exhibits a ZT value of 0.6 at 125 °C, i.e. far below the decomposition temperature and thus is an interesting new low-temperature thermoelectric material

    Spectrophotometric Characterization of Thin Semi-Transparent Aluminum Films Prepared by Electron Beam Evaporation and Magnetron Sputtering

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    Aluminum thin films with thicknesses between approximately 10 and 60 nm have been deposited by evaporation and sputtering techniques. Layer characterization focused on reflectance, optical constants, and surface quality. Reflectance fits have been performed using a merger of three standard dispersion models, namely the Drude model, the Lorentzian oscillator model, and the beta-distributed oscillator model. A thickness dependence of the optical constants could be established in the investigated thickness range

    Peer review analysis in the field of radiation oncology: results from a web-based survey of the Young DEGRO working group

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    PURPOSE To evaluate the reviewing behaviour in the German-speaking countries in order to provide recommendations to increase the attractiveness of reviewing activity in the field of radiation oncology. METHODS In November 2019, a survey was conducted by the Young DEGRO working group (jDEGRO) using the online platform “eSurveyCreator”. The questionnaire consisted of 29 items examining a~broad range of factors that influence reviewing motivation and performance. RESULTS A total of 281 responses were received. Of these, 154 (55%) were completed and included in the evaluation. The most important factors for journal selection criteria and peer review performance in the field of radiation oncology are the scientific background of the manuscript (85%), reputation of the journal (59%) and a~high impact factor (IF; 40%). Reasons for declining an invitation to review include the scientific background of the article (60%), assumed effort (55%) and a low IF (27%). A~double-blind review process is preferred by 70% of respondents to a single-blind (16%) or an open review process (14%). If compensation was offered, 59% of participants would review articles more often. Only 12% of the participants have received compensation for their reviewing activities so far. As compensation for the effort of reviewing, 55% of the respondents would prefer free access to the journal's articles, 45% a discount for their own manuscripts, 40% reduced congress fees and 39% compensation for expenses. CONCLUSION The scientific content of the manuscript, reputation of the journal and a~high IF determine the attractiveness for peer reviewing in the field of radiation oncology. The majority of participants prefer a~double-blind peer review process and would conduct more reviews if compensation was available. Free access to journal articles, discounts for publication costs or congress fees, or an expense allowance were identified to increase attractiveness of the review process

    Nanostructures in Te/Sb/Ge/Ag (TAGS) Thermoelectric Materials Induced by Phase Transitions Associated with Vacancy Ordering

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    Te/Sb/Ge/Ag (TAGS) materials with rather high concentrations of cation vacancies exhibit improved thermoelectric properties as compared to corresponding conventional TAGS (with constant Ag/Sb ratio of 1) due to a significant reduction of the lattice thermal conductivity. There are different vacancy ordering possibilities depending on the vacancy concentration and the history of heat treatment of the samples. In contrast to the average α-GeTe-type structure of TAGS materials with cation vacancy concentrations <3%, quenched compounds like Ge_(0.53)Ag_(0.13)Sb_(0.27)□_(0.07)Te_1 and Ge_(0.61)Ag_(0.11)Sb_(0.22)□_(0.06)Te_1 exhibit “parquet-like” multidomain nanostructures with finite intersecting vacancy layers. These are perpendicular to the pseudocubic 111 directions but not equidistantly spaced, comparable to the nanostructures of compounds (GeTe)_nSb_2Te_3. Upon heating, the nanostructures transform into long-periodically ordered trigonal phases with parallel van der Waals gaps. These phases are slightly affected by stacking disorder but distinctly different from the α-GeTe-type structure reported for conventional TAGS materials. Deviations from this structure type are evident only from HRTEM images along certain directions or very weak intensities in diffraction patterns. At temperatures above 400 °C, a rock-salt-type high-temperature phase with statistically disordered cation vacancies is formed. Upon cooling, the long-periodically trigonal phases are reformed at the same temperature. Quenched nanostructured Ge_(0.53)Ag_(0.13)Sb_(0.27)□_(0.07)Te_1 and Ge_(0.61)Ag_(0.11)Sb_(0.22)□_(0.06)Te_1 exhibit ZT values as high as 1.3 and 0.8, respectively, at 160 °C, which is far below the phase transition temperatures. After heat treatment, i.e., without pronounced nanostructure and when only reversible phase transitions occur, the ZT values of Ge_(0.53)Ag_(0.13)Sb_(0.27)□_(0.07)Te_1 and Ge_(0.61)Ag_(0.11)Sb_(0.22)□_(0.06)Te_1 with extended van der Waals gaps amount to 1.6 at 360 °C and 1.4 at 410 °C, respectively, which is at the top end of the range of high-performance TAGS materials

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis
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