Разработка технологии изготовления свс-фильтров из интерметаллидов никеля и алюминия

Приведен массовый состав исходной шихты для самораспространяющегося высокотемпературного синтеза интерметаллидов в зависимости от содержания никеля в шихте. Изложена методика и порядок технологических операций при изготовлении фильтров различных размеров и геометрической формы, а также пути регулирования пористой структуры и способы их реализации

The Three Faces of Omega_m: Testing Gravity with Low and High Redshift SN Ia Surveys

Peculiar velocities of galaxies hosting Type Ia supernovae generate a significant systematic effect in deriving the dark energy equation of state w, at level of a few percent. Here we illustrate how the peculiar velocity effect in SN Ia data can be turned from a 'systematic' into a probe of cosmological parameters. We assume a flat Lambda-Cold Dark Matter model (w=-1) and use low and high redshift SN Ia data to derive simultaneously three distinct estimates of the matter density Omega_m which appear in the problem: from the geometry, from the dynamics and from the shape of the matter power spectrum. We find that each of the three Omega_m's agree with the canonical value Omega_m=0.25 to within 1 sigma, for reasonably assumed fluctuation amplitude and Hubble parameter. This is consistent with the standard cosmological scenario for both the geometry and the growth of structure. For fixed Omega_m = 0.25 for all three Omega_m's, we constrain gamma = 0.72 +/- 0.21 in the growth factor Omega_m(z)^gamma, so we cannot currently distinguish between standard Einstein gravity and predictions from some modified gravity models. Future surveys of thousands of SN Ia, or inclusion of peculiar velocity data, could significantly improve the above tests.Comment: accepted for publication in MNRAS (Letters), 5 pages, 4 figures. Small changes to improve the text and the figures. Some further discussion, 1 equation and 1 reference adde

Integrating biological vasculature into a multi-organ-chip microsystem

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.A chip-based system mimicking the transport function of the human cardiovascular system has been established at minute but standardized microsystem scale. A peristaltic on-chip micropump generates pulsatile shear stress in a widely adjustable physiological range within a microchannel circuit entirely covered on all fluid contact surfaces with human dermal microvascular endothelial cells. This microvascular transport system can be reproducibly established within four days, independently of the individual endothelial cell donor background. It interconnects two standard tissue culture compartments, each of 5 mm diameter, through microfluidic channels of 500 μm width. Further vessel branching and vessel diameter reduction down to a microvessel scale of approximately 40 μm width was realised by a two-photon laser ablation technique applied to inserts, designed for the convenient establishment of individual organ equivalents in the tissue culture compartments at a later time. The chip layout ensures physiological fluid-to-tissue ratios. Moreover, an in-depth microscopic analysis revealed the fine-tuned adjustment of endothelial cell behaviour to local shear stresses along the microvasculature of the system. Time-lapse and 3D imaging two-photon microscopy were used to visualise details of spatiotemporal adherence of the endothelial cells to the channel system and to each other. The first indicative long-term experiments revealed stable performance over two and four weeks. The potential application of this system for the future establishment of human-on-a-chip systems and basic human endothelial cell research is discussed.BMBF, 0315569, GO-Bio 3: Multi-Organ-Bioreaktoren für die prädiktive Substanztestung im Chipforma

Cardiac displacement tracking with data assimilation combining a biomechanical model and an automatic contour detection

International audienceData assimilation in computational models represents an essential step in building patient-specific simulations. This work aims at circumventing one major bottleneck in the practical use of data assimilation strategies in cardiac applications, namely, the difficulty of formulating and effectively computing adequate data-fitting term for cardiac imaging such as cine MRI. We here provide a proof-of-concept study of data assimilation based on automatic contour detection. The tissue motion simulated by the data assimilation framework is then assessed with displacements extracted from tagged MRI in six subjects, and the results illustrate the performance of the proposed method, including for circumferential displacements, which are not well extracted from cine MRI alone

Acetazolamide to Prevent Adverse Altitude Effects in COPD and Healthy Adults

Background We evaluated the efficacy of acetazolamide in preventing adverse altitude effects in patients with moderate to severe chronic obstructive pulmonary disease (COPD) and in healthy lowlanders 40 years of age or older. Methods Trial 1 was a randomized, double-blind, parallel-design trial in which 176 patients with COPD were treated with acetazolamide capsules (375 mg/day) or placebo, starting 24 hours before staying for 2 days at 3100 m. The mean (±SD) age of participants was 57±9 years, and 34% were women. At 760 m, COPD patients had oxygen saturation measured by pulse oximetry of 92% or greater, arterial partial pressure of carbon dioxide less than 45 mm Hg, and mean forced expiratory volume in 1 second of 63±11% of predicted. The primary outcome in trial 1 was the incidence of the composite end point of altitude-related adverse health effects (ARAHE) at 3100 m. Criteria for ARAHE included acute mountain sickness (AMS) and symptoms or findings relevant to well-being and safety, such as severe hypoxemia, requiring intervention. Trial 2 comprised 345 healthy lowlanders. Their mean age was 53±7 years, and 69% were women. The participants in trial 2 underwent the same protocol as did the patients with COPD in trial 1. The primary outcome in trial 2 was the incidence of AMS assessed at 3100 m by the Lake Louise questionnaire score (the scale of self-assessed symptoms ranges from 0 to 15 points, indicating absent to severe, with 3 or more points including headache, indicating AMS). Results In trial 1 of patients with COPD, 68 of 90 (76%) receiving placebo and 42 of 86 (49%) receiving acetazolamide experienced ARAHE (hazard ratio, 0.54; 95% confidence interval [CI], 0.37 to 0.79; P<0.001). The number needed to treat (NNT) to prevent one case of ARAHE was 4 (95% CI, 3 to 8). In trial 2 of healthy individuals, 54 of 170 (32%) receiving placebo and 38 of 175 (22%) receiving acetazolamide experienced AMS (hazard ratio, 0.48; 95% CI, 0.29 to 0.80; chi-square statistic P=0.035). The NNT to prevent one case of AMS was 10 (95% CI, 5 to 141). No serious adverse events occurred in these trials. Conclusions Preventive treatment with acetazolamide reduced the incidence of adverse altitude effects requiring an intervention in patients with COPD and the incidence of AMS in healthy lowlanders 40 years of age or older during a high-altitude sojourn. (Funded by the Swiss National Science Foundation [Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung], Lunge Zürich, and the Swiss Lung Foundation; ClinicalTrials.gov numbers, NCT03156231 and NCT03561675.

Operationalization of a multidimensional sex/gender concept for quantitative environmental health research and implementation in the KORA study: Results of the collaborative research project INGER

BackgroundIn environmental health research, sex and gender are not yet adequately considered. There is a need to improve data collection in population-based environmental health studies by comprehensively surveying sex/gender-related aspects according to gender theoretical concepts. Thus, within the joint project INGER we developed a multidimensional sex/gender concept which we aimed to operationalize and to test the operationalization for feasibility.MethodsIn an iterative process, we created questionnaire modules which quantitatively captured the requirements of the INGER sex/gender concept. We deployed it in the KORA cohort (Cooperative Health Research in the Region of Augsburg, Germany) in 2019 and evaluated response and missing rates.ResultsThe individual sex/gender self-concept was surveyed via a two-step approach that asked for sex assigned at birth and the current sex/gender identity. Additionally, we used existing tools to query internalized sex/gender roles and externalized sex/gender expressions. Adapted to the KORA population, we asked for discrimination experiences and care and household activities contributing to explain structural sex/gender relations. Further intersectionality-related social categories (e.g., socio-economic position), lifestyle and psychosocial factors were covered through data available in KORA. We could not identify appropriate tools to assess the true biological sex, sexual orientation and ethnic/cultural identity, which have yet to be developed or improved. The response-rate was 71%, the evaluation of 3,743 questionnaires showed a low missing rate. Prevalence of marginalized groups regarding sex/gender identity and definable by experiences of discrimination was very low.ConclusionWe have shown how the multidimensional INGER sex/gender concept can be operationalized according to an European and North American understanding of sex/gender for use in quantitative research. The questionnaire modules proved feasible in an epidemiologic cohort study. Being a balancing act between theoretical concepts and its quantitative implementation our operationalization paves the way for an adequate consideration of sex/gender in environmental health research

Peculiar Velocities into the Next Generation: Cosmological Parameters From Large Surveys without Bias from Nonlinear Structure

We investigate methods to best estimate the normalisation of the mass density fluctuation power spectrum (sigma_8) using peculiar velocity data from a survey like the Six degree Field Galaxy Velocity Survey (6dFGSv). We focus on two potential problems (i) biases from nonlinear growth of structure and (ii) the large number of velocities in the survey. Simulations of LambdaCDM-like models are used to test the methods. We calculate the likelihood from a full covariance matrix of velocities averaged in grid cells. This simultaneously reduces the number of data points and smooths out nonlinearities which tend to dominate on small scales. We show how the averaging can be taken into account in the predictions in a practical way, and show the effect of the choice of cell size. We find that a cell size can be chosen that significantly reduces the nonlinearities without significantly increasing the error bars on cosmological parameters. We compare our results with those from a principal components analysis following Watkins et al (2002) and Feldman et al (2003) to select a set of optimal moments constructed from linear combinations of the peculiar velocities that are least sensitive to the nonlinear scales. We conclude that averaging in grid cells performs equally well. We find that for a survey such as 6dFGSv we can estimate sigma_8 with less than 3% bias from nonlinearities. The expected error on sigma_8 after marginalising over Omega_m is approximately 16 percent.Comment: Accepted for publication in MNRAS, 12 pages, 5 figures. V2 Discussion clarified, 1 figure added, improvements to the text and figures; V3 Figure 5 Plotting error corrected, SN1a contours smalle

Zwitterionically modified alginates mitigate cellular overgrowth for cell encapsulation

Foreign body reaction (FBR) to implanted biomaterials and medical devices is common and can compromise the function of implants or cause complications. For example, in cell encapsulation, cellular overgrowth (CO) and fibrosis around the cellular constructs can reduce the mass transfer of oxygen, nutrients and metabolic wastes, undermining cell function and leading to transplant failure. Therefore, materials that mitigate FBR or CO will have broad applications in biomedicine. Here we report a group of zwitterionic, sulfobetaine (SB) and carboxybetaine (CB) modifications of alginates that reproducibly mitigate the CO of implanted alginate microcapsules in mice, dogs and pigs. Using the modified alginates (SB-alginates), we also demonstrate improved outcome of islet encapsulation in a chemically-induced diabetic mouse model. These zwitterion-modified alginates may contribute to the development of cell encapsulation therapies for type 1 diabetes and other hormone-deficient diseases