OEXP Analysis Tools Workshop

This publication summarizes the software needs and available analysis tools presented at the OEXP Analysis Tools Workshop held at the NASA Langley Research Center, Hampton, Virginia on June 21 to 22, 1988. The objective of the workshop was to identify available spacecraft system (and subsystem) analysis and engineering design tools, and mission planning and analysis software that could be used for various NASA Office of Exploration (code Z) studies, specifically lunar and Mars missions

Conceptual design of a synchronous Mars telecommunications satellite

Future missions to Mars will require a communications system to link activities on the Martian surface with each other and with mission controllers on Earth. A conceptual design is presented for an aerosynchronous communications satellite to provide these links. The satellite provides the capability for voice, data/command, and video transmissions. The mission scenario assumed for the design is described, and a description of a single aerosynchronous satellite is explained. A viable spacecraft design is then presented. Communication band selection and channel allocation are discussed. The communications system conceptual design is presented along with the trades used in sizing each of the required antennas. Also, the analyses used to develop the supporting subsystem designs are described as is the communications impact on each subsystem design

Cardiac spheroids as promising in vitro models to study the human heart microenvironment.

Three-dimensional in vitro cell systems are a promising alternative to animals to study cardiac biology and disease. We have generated three-dimensional in vitro models of the human heart ("cardiac spheroids", CSs) by co-culturing human primary or iPSC-derived cardiomyocytes, endothelial cells and fibroblasts at ratios approximating those present in vivo. The cellular organisation, extracellular matrix and microvascular network mimic human heart tissue. These spheroids have been employed to investigate the dose-limiting cardiotoxicity of the common anti-cancer drug doxorubicin. Viability/cytotoxicity assays indicate dose-dependent cytotoxic effects, which are inhibited by the nitric oxide synthase (NOS) inhibitor L-NIO, and genetic inhibition of endothelial NOS, implicating peroxynitrous acid as a key damaging agent. These data indicate that CSs mimic important features of human heart morphology, biochemistry and pharmacology in vitro, offering a promising alternative to animals and standard cell cultures with regard to mechanistic insights and prediction of toxic effects in human heart tissue

NOUVELLE APPROCHE DE LA METHODE DES VOLUMES FINIS ‘MVF’ DEDIEE A LA RESOLUTION DES PROBLEMES ELECTROMAGNETIQUES 3D

Nous proposons dans le cadre de ce travail une nouvelle approche de la méthode des volumes finis dédié principalement à lamodélisation tridimensionnelle des phénomènes électromagnétiques au sein des dispositifs électrotechniques. Le maillageadopté est un maillage non-structuré qui requiert un mailleur indépendant, spécifique, parfaitement adapté à l’algorithmenumérique. Son rôle est de partitionner l’application étudiée en cellules élémentaires de forme aussi variée que des trianglesdans le cas bidimensionnel et tétraèdres voir prismatique dans le cas tridimensionnel. Cette approche est avantageuse comparéeaux approches présentées dans des travaux précédents par le faite quelle s’adapte parfaitement à la modélisationtridimensionnelle des problèmes électromagnétiques dans des dispositifs ayants des géométries complexe d’une part, d’autrepart, elle peut résoudre des problèmes électromagnétiques où les matériaux magnétiques sont utilisés dans la conception desdispositifs étudiés, contrairement à celles déjà présenté précédemment, où seulement on peut traiter les problèmes ayant desdispositifs conçut à partir des matériaux amagnétiques [1] voir diamagnétiques [2] comme par exemple les matériauxsupraconducteurs à haute température critique. L’ensemble des modèles mathématiques et numériques est implémenté dans uncode de calcul tridimensionnel sous environnement Matlab. La validité du travail présenté est atteinte par la comparaison desrésultats obtenus avec des résultats expérimentaux trouvés dans la littérature [3]

Stereocontrolled, multi-functional sequence-defined oligomers through automated synthesis

In contrast to biomacromolecules, synthetic polymers generally lack a defined monomer sequence, therefore one of the challenges of polymer chemists these days is gaining more control over the primary structure of synthetic polymers and oligomers. In this work, stereocontrolled sequence-defined oligomers were synthesised using a thiolactone-based platform. Step-wise elongation of the oligomer occursviaring-opening of the thiolactone, resulting in the formation of stereocenters along the backbone. These initial studies indicate remarkable differences in the strength of non-covalent interactions in isotactic and atactic oligomers. Different side-chain moieties were introduced using alkyl halide building blocks and the synthetic protocol was succesfully optimised and automated. Furthermore, the possible post-synthesis modification of the oligomers was demonstrated using 'click' chemistry

Mobile applications in government services (mG-App) from user's perspectives: A predictive modelling approach

YesMobile applications are becoming a preferred delivery method for the government sector and contributing to more convenient and timely services to citizens. This study examines the intention to use mobile applications for the government services (mG-App) in Oman. This study extended the Unified Theory of Acceptance and Use of Technology (UTAUT) model by including two constructs namely trust and information quality. Data were collected from 513 mobile application users across Oman. The research model was analysed in two stages. First, structural equation modelling (SEM) was employed to determine significant determinants affecting users’ acceptance of mG-App. In the second stage, a neural network model was used to validate SEM results and determine the relative importance of determinants of acceptance of mG-App. The findings revealed that trust and performance expectancy are the strongest determinants influencing the acceptance of mG-App. The findings of this research have provided theoretical contributions to the existing research on mG-App and practical implications to decision-makers involved in the development and implementation of mG-App in in Oman

Effet du dilueur et de la température du stockage sur les paramètres de motilité des spermatozoïdes du bélier conservés à l’état liquide

The objective of this work was to compare the effect of eight extenders (Skim milk, INRA96®, Tris Eggs Yolk, Triladyl®, Ovipro®, Andromed®, Optixcel® and Duragen®) on ram sperm motion parameters. Two experiments were carried out to determine the effect of extenders on ram sperm preservation at 15°C (Experiment 1), or at 5°C (Experiment 2). Semen was collected using an artificial vagina weekly for 10 weeks from two breeds (INRA180, n=4, on Monday and Boujaâd, n=4, on Friday). Aliquots were extended in each extender to a final concentration of 0.8 × 109 spermatozoa/ml and stored at 15°C or 5°C for 24 h. Motility and kinematic parameters assessment were performed using a CASA system. Sperm motility and kinematic parameters decreased significantly over time of storage in all extenders and storage temperature. The overall CASA parameters were affected by extenders in different manners depending on breed and storage temperature. Skim milk, Duragen®, and INRA96® provided the best CASA results. Keywords: Semen, extender, motility, kinematic parameters, storage temperature, ram breed.L’objectif de ce travail était de comparer l’effet de huit dilueurs (lait écrémé, INRA96®, Tris jaune d’œuf, Triladyl®, Ovipro®, Andromed®, Optixcel® et Duragen®) sur les paramètres du mouvement du sperme du bélier. Deux expérimentations ont été réalisées pour déterminer l’effet des dilueurs sur la conservation du sperme de bélier à 15°C (expérimentation 1), ou à 5°C (expérimentation 2). Le sperme a été collecté à l’aide d’un vagin artificiel chaque semaine durant 10 semaines des deux races ovines (INRA180, n=4, lundi et Boujaâd, n=4, vendredi). Des aliquotes du sperme ont été diluées dans chaque dilueur à une concentration finale de 0,8 x 109 spermatozoïdes/ml et conservées à 15°C ou 5°C durant 24 heures. La motilité et les paramètres cinétiques ont été évalués à l’aide d’un système CASA. La motilité des spermatozoïdes et les paramètres cinétiques ont diminué significativement au cours du temps de stockage dans tous les dilueurs et les températures de stockage. Les dilueur ont affecté les paramètres générés par le système CASA de différentes manières en fonction de la race et de la température du stockage. Le lait écrémé, Duragen® et INRA96® ont fourni les meilleurs résultats de CASA. Mots-clés: Sperme, dilueurs, motilité, paramètres cinétiques, température du stockage, race du bélier

MicroRNA Changes Up to 24 h following Induced Hypoglycemia in Type 2 Diabetes

Hypoglycemia, as a complication of type 2 diabetes (T2D), causes increased morbidity and mortality but the physiological response underlying hypoglycemia has not been fully elucidated. Small noncoding microRNA (miRNA) have multiple downstream biological effects. This pilot exploratory study was undertaken to determine if induced miRNA changes would persist and contribute to effects seen 24 h post-hypoglycemia. A parallel, prospective study design was employed, involving T2D (n = 23) and control (n = 23) subjects. The subjects underwent insulin-induced hypoglycemia (2 mmol/L; 36 mg/dL); blood samples were drawn at baseline, upon the induction of hypoglycemia, and 4 h and 24 h post-hypoglycemia, with a quantitative polymerase chain reaction analysis of miRNA undertaken. The baseline miRNAs did not differ. In the controls, 15 miRNAs were downregulated and one was upregulated (FDR < 0.05) from the induction of hypoglycemia to 4 h later while, in T2D, only four miRNAs were altered (downregulated), and these were common to both cohorts (miR-191-5p; miR-143-3p; let-7b-5p; let-7g-5p), correlated with elevated glucagon levels, and all were associated with energy balance. From the induction of hypoglycemia to 24 h, 14 miRNAs were downregulated and 5 were upregulated (FDR < 0.05) in the controls; 7 miRNAs were downregulated and 7 upregulated (FDR < 0.05) in T2D; a total of 6 miRNAs were common between cohorts, 5 were downregulated (miR-93-5p, let-7b-5p, miR-191-5p, miR-185-5p, and miR-652-3p), and 1 was upregulated (miR-369-3p). An ingenuity pathway analysis indicated that many of the altered miRNAs were associated with metabolic and coagulation pathways; however, of the inflammatory proteins expressed, only miR-143-3p at 24 h correlated positively with tumor necrosis factor-α (TNFa; p < 0.05 and r = 0.46) and negatively with toll-like receptor-4 (TLR4; p < 0.05 and r = 0.43). The MiRNA levels altered by hypoglycemia reflected changes in counter-regulatory glucagon and differed between cohorts, and their expression at 24 h suggests miRNAs may potentiate and prolong the physiological response. Trial registration: ClinicalTrials.gov NCT03102801