291 research outputs found

    Involvement of spectrin in cell-surface receptor capping in lymphocytes.

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    Anaerobic Threshold Individualized Assessment in a Young Swimmer

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    A contemporary dose selection algorithm for stereotactic radiosurgery in the treatment of brain metastases - An initial report.

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    Indications and treatment goals for SRS have changed since the publication of RTOG 90-05. We present initial retrospective outcomes from a new dose selection algorithm in use at our institution felt to be more contemporary with doses being used in the radiosurgery community today and report our local control and toxicity outcomes. This dose selection algorithm will be subject to a forthcoming prospective phase 2 trial.To evaluate safety and efficacy of an institutional dose selection algorithm in the treatment of brain metastases (BM) with single fraction radio-surgery (SRS).The medical records of 65 patients with ≤10 BM treated with GK at our institution between April 2012 and October 2012 were reviewed retrospectively. The prescription doses used in this study ranged from 16-22Gy and were based upon RTOG 90-05 guideline doses subsequently modified at our institution depending on lesion number, lesion volume, institutional experience and prior history of whole brain radiation therapy (WBRT). Primary endpoint was local recurrence (LR) with additional outcomes measured including distant intracranial recurrence (DIR), death without local recurrence (DWLR) and alive and disease free (ADF). Fine Gray competing risk analysis was used to examine factors affecting local recurrence.Median follow up was 8.9 months (range 1.0-29.6months) and 12 month overall survival was 37% (95% CI 24.9-49.1%). Overall local recurrence rate was 7.7%. On competing risks regression analysis, no variable was significantly associated with local recurrence, including previous whole brain radiotherapy (WBRT), (SHR 1.21 [95%CI 0.13-11.5], p=0.87 and radioresistant versus radiosensitive histology (SHR 0.51 [95% CI 0.06-7.73], p=0.55). No patient developed grade 3 or higher neurotoxicity at 12 months following GK.Initial local control and toxicity results from our institutional dose selection algorithm are reported here. Comparison of our results with RTOG 90-05 is difficult due to significant differences in the patient population and their treatments. The applicability of this algorithm merits further investigation across multiple centers for the purpose of treatment and clinical trial standardization in single fraction SRS and will be the subject of a forthcoming phase 2 prospective study within our own institution

    Report of the ICES\NAFO Joint Working Group on Deep-water Ecology (WGDEC), 11–15 March 2013, Floedevigen, Norway.

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    On 11 February 2013, the joint ICES/NAFO WGDEC, chaired by Francis Neat (UK) and attended by ten members met at the Institute for Marine Research in Floedevi-gen, Norway to consider the terms of reference (ToR) listed in Section 2. WGDEC was requested to update all records of deep-water vulnerable marine eco-systems (VMEs) in the North Atlantic. New data from a range of sources including multibeam echosounder surveys, fisheries surveys, habitat modelling and seabed imagery surveys was provided. For several areas across the North Atlantic, WGDEC makes recommendations for areas to be closed to bottom fisheries for the purposes of conservation of VMEs

    A Clinically Relevant Variant of the Human Hydrogen Sulfide-Synthesizing Enzyme Cystathionine β -Synthase: Increased CO Reactivity as a Novel Molecular Mechanism of Pathogenicity?

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    The human disease classical homocystinuria results from mutations in the gene encoding the pyridoxal 5′-phosphate- (PLP-) dependent cystathionine β-synthase (CBS), a key enzyme in the transsulfuration pathway that controls homocysteine levels, and is a major source of the signaling molecule hydrogen sulfide (H2S). CBS activity, contributing to cellular redox homeostasis, is positively regulated by S-adenosyl-L-methionine (AdoMet) but fully inhibited upon CO or NO• binding to a noncatalytic heme moiety. Despite extensive studies, the molecular basis of several pathogenic CBS mutations is not yet fully understood. Here we found that the ferrous heme of the reportedly mild p.P49L CBS variant has altered spectral properties and markedly increased affinity for CO, making the protein much more prone than wild type (WT) CBS to inactivation at physiological CO levels. The higher CO affinity could result from the slightly higher flexibility in the heme surroundings revealed by solving at 2.80-Å resolution the crystallographic structure of a truncated p.P49L. Additionally, we report that p.P49L displays impaired H2S-generating activity, fully rescued by PLP supplementation along the purification, despite a minor responsiveness to AdoMet. Altogether, the results highlight how increased propensity to CO inactivation of an otherwise WT-like variant may represent a novel pathogenic mechanism in classical homocystinuria

    Application of particle filters to regional-scale wildfire spread

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    European Conference on Thermophysical Properties (ECTP)European Conference on Thermophysical Properties (ECTP), Porto, PORTUGALPorto, PORTUGAL, SEP 05-05, 2014SEP 05-05, 2014International audienceThis paper demonstrates the capability of particle filters for sequentially improving the simulation and forecast of wildfire propagation as new fire front observations become available. Particle filters, also called Sequential Monte Carlo (SMC) methods, fit into the domain of inverse modeling procedures, where measurements are incorporated (assimilated) into a computational model so as to formulate some feedback information on the uncertain model state variables and/or parameters, through representations of their probability density functions (PDF). Based on a simple sampling importance distribution and resampling techniques, particle filters combine Monte Carlo samplings with sequential Bayesian filtering problems. This study compares the performance of the Sampling Importance Resampling (SIR) and of the Auxiliary Sampling Importance Resampling (ASIR) filters for the sequential estimation of a progress variable and of vegetation parameters of the Rate Of fire Spread (ROS) model, which are all treated as state variables. They are applied to a real-world case corresponding to a reduced-scale controlled grassland fire experiment for validation; results indicate that both the SIR and the ASIR filters are able to accurately track the observed fire fronts, with a moderate computational cost. Particle filters show, therefore, their good ability to predict the propagation of controlled fires and to significantly increase fire simulation accuracy. While still at an early stage of development, this data-driven strategy is quite promising for regional-scale wildfire spread forecasting

    Algorithms for design optimization of chemistry of hard magnetic alloys using experimental data

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    A multi-dimensional random number generation algorithm was used to distribute chemical concentrations of each of the alloying elements in the candidate alloys as uniformly as possible while maintaining the prescribed bounds on the minimum and maximum allowable values for the concentration of each of the alloying elements. The generated candidate alloy compositions were then examined for phase equilibria and associated magnetic properties using a thermodynamic database in the desired temperature range. These initial candidate alloys were manufactured, synthesized and tested for desired properties. Then, the experimentally obtained values of the properties were fitted with a multi-dimensional response surface. The desired properties were treated as objectives and were extremized simultaneously by utilizing a multi-objective optimization algorithm that optimized the concentrations of each of the alloying elements. This task was also performed by another conceptually different response surface and optimization algorithm for double-checking the results. A few of the best predicted Pareto optimal alloy compositions were then manufactured, synthesized and tested to evaluate their macroscopic properties. Several of these Pareto optimized alloys outperformed most of the candidate alloys on most of the objectives. This proves the efficacy of the combined meta-modeling and experimental approach in design optimization of the alloys. A sensitivity analysis of each of the alloying elements was also performed to determine which of the alloying elements contributes the least to the desired macroscopic properties of the alloy. These elements can then be replaced with other candidate alloying elements such as not-so-rare earth elements

    Deep Eutectic Solvents (DES) based on sulphur for silicon surfaces as alternative lubricants

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    Encontro realizado na Universidade Nova de Lisboa de 24-27 de junho de 2019.Deep eutectic mixtures composed of hydrogen-bond donors and hydrogen-bond acceptors, the so-called DESs, have recently being proposed as possible “green” alternatives to mineral oils and ionic liquids (ILs) in the lubrication of steel surfaces. DESs have similar physical properties to ILs but have the advantage of being cheaper and easier to prepare. In this work, new DESs containing sulphur units in their structure were prepared and tested in the lubrication of silicon surfaces which are relevant for nano/microelectromechanical systems (NEMS/MEMS). The following new DESs were prepared: dibutil-ethyl sulfonium ethylsulfate: polyethylene glycol ([S4,4,2][EtSO4]:PEG), ethyl-tetrahydrothiophenium ethylsulfate: polyethylene glycol ([C2-THT][EtSO4]:PEG, cis-1-ethyl-3methylimidazolium canforsulfonate: polyethylene glycol ([C2MIM][(S)-CSA]:PEG), and 1,3-dimethylpiridinium methyl sulfate: polyethylene glycol ([C1-3-pic][MeSO4]:PEG). Other DES, already known, were tested for comparison purposes: tetrabutylammonium bromide: ‎tetrahydrothiophene 1,1-dioxide ([N4,4,4,4][Br]:Sulfolane), choline chloride: polyethylene glycol (ChCl:PEG), and tetrabutylammonium bromide: polyethylene glycol ([N4,4,4,4][Br]:PEG). All DESs were characterized in terms of their water content, viscosity, wettability, and tribological properties. The friction coefficients were measured in a nanotribometer using steel spheres against Si surfaces. The new DES prepared from ILs based on the sulfur-containing anions showed good tribological performance, but the best results were obtained with [C2MIM][(S)-CSA]:PEG and [C1-3-pic][MeSO4]:PEG which reduced the friction coefficients to values < 0.1, typical of excellent lubrication conditions.Fundação para a Ciência e a Tecnologia (FCT-Portugal) and COMPETE (FEDER), within projects UID/QUI/00100/2013, UID/NAN/50024/2013 and PTDC/CTM-POL/3698/2014info:eu-repo/semantics/draf
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