Electronic Nose Functionality for Breath Gas Analysis during Parabolic Flight

The presence of humans in space represents a constant threat for their health and safety. Environmental factors such as living in a closed confinement, as well as exposure to microgravity and radiation, are associated with significant changes in bone metabolism, muscular atrophy, and altered immune response, which has impacts on human performance and possibly results in severe illness. Thus, maintaining and monitoring of crew health status has the highest priority to ensure whole mission success. With manned deep space missions to moon or mars appearing at the horizon where short-term repatriation back to earth is impossible the availability of appropriate diagnostic platforms for crew health status is urgently needed. In response to this need, the present experiment evaluated the functionality and practicability of a metal oxide based sensor system (eNose) together with a newly developed breath gas collecting device under the condition of altering acceleration. Parabolic flights were performed with an Airbus A300 ZeroG at Bordeaux, France. Ambient air and exhaled breath of five healthy volunteers was analyzed during steady state flight and parabolic flight maneuvres. All volunteers completed the study, the breath gas collecting device valves worked appropriately, and breathing through the collecting device was easy and did not induce discomfort. During breath gas measurements, significant changes in metal oxide sensors, mainly sensitive to aromatic and sulphur containing compounds, were observed with alternating conditions of acceleration. Similarly, metal oxide sensors showed significant changes in all sensors during ambient air measurements. The eNose as well as the newly developed breath gas collecting device, showed appropriate functionality and practicability during alternating conditions of acceleration which is a prerequisite for the intended use of the eNose aboard the International Space Station (ISS) for breath gas analysis and crew health status monitoring. The observed changes in breath gas composition are most likely associated with changes in ambient air volatile organic and inorganic compound composition and require further evaluation.     

High-Precision Nucleation Rate Measurements for Higher Melting Metals

Nucleation of a crystal in undercooled melts of higher melting face-centered-cubic-metals has often been studied in the past. However, the data available were not of sufficient accuracy and only covered nucleation rates in too small of a range to allow precise conclusions concerning the nature of the underlying process as well as concerning important parameters such as the solid–liquid interface free energy that can in principle be deducted from such analyses. One way to circumvent ambiguities and analyze nucleation kinetics under well-defined conditions experimentally is given by performing statistically significant numbers of repeated single droplet experiments. Application of proper statistics analyses yields nucleation rates that are independent of a specific nucleation model. The first studies that were conducted in accordance with this approach on pure model materials revealed that the approach is valid. The results are comparable to those obtained by classic nucleation theory applied to experimental data, and it was shown that one might need to rethink the common assumption that heterogeneous nucleation is almost always responsible for solidification initiation. The current results also show that often-used models for the solid–liquid interface free energy might lead to overestimated values.     

All in good time: knowledge introduction,restructuring, and development of shared opinions as different stages in collaborative writing

When learners collaborate with each other in order to elaborate on a particular subject, this collaboration may be influenced by the differing perspectives the learners have on the topic. There has been very little research to date on how differing perspectives have an impact in collaboration situations in which people are supposed to form a shared opinion on a particular topic. In this study, we analyzed which stages people’s activities pass through on their way to reaching shared opinions in a collaborative writing task. We examined how dyads of secondary school students, who in a previous instructional session had dealt with differing theoretical approaches to media effects, collaborated in writing a shared text about the topic of media violence. Quantitative analysis indicated that the participants engaged in different activities at different stages of the collaboration processes: In the early stages they were predominantly engaged in introducing the knowledge that they had acquired in the previous lesson. This activity was replaced in the middle stage of the collaboration by restructuring activities. Forming and phrasing shared opinions rarely occurred until very late in the collaboration, but played the leading role in the final stage. We applied a qualitative content analysis to illustrate these different activities by presenting examples of the collaboratively written texts. In doing so, we discuss the distinct activities as well as their character and functionalities for collaboration.     

Effects of calcium chloride and calcium lactate applications with osmotic pretreatment on physicochemical aspects and consumer acceptances of dried papaya

This study explored the effects of calcium chloride (CaCl₂) and calcium lactate (Ca‐L) pretreatments prior to osmotic dehydration on physicochemical characteristics and consumer acceptance of dried papaya. Three different calcium concentrations [0.5, 1.5 and 2.5% (w/v)] were applied to samples before they were soaked in a 30 °Brix sucrose solution and subsequently dried at 70 °C. The results showed that the dried samples treated with calcium exhibited significantly lower moisture content, water activity, apparent density and shrinkage, while volume was higher when compared to the control. Calcium applications did not obviously influence sugar content of samples and maintained the quality of dried papaya in terms of colour and textural characteristics. Calcium chloride at 2.5% (w/v) was found to particularly impart undesirable bitterness to the dried papaya. In contrast, using 2.5% (w/v) Ca‐L provided the best acceptance scores. Thus, the use of Ca‐L could be an alternative to CaCl₂ in the pretreatment of fruits prior to drying as it offers improved quality.     

Development of bottleneck detection methods allowing for an effective fault repair prioritization in machining lines of the automobile industry

Fault repair prioritization is an important topic for organizing operators in every plant where their numbers are restricted. Prioritization helps the operators to focus on critical machines to increase the machining line’s output. The goal of this paper is to define and test effective fault repair prioritization methods based on analytically identified bottlenecks. For that purpose, several bottleneck detection methods known from the literature were analyzed; however, none of them was able to be used for a fault repair prioritization in typical machining lines of the automobile industry. Hence, three new bottleneck detection methods are going to be introduced in this paper. The new methods focus on the detection of short-term and real-time bottlenecks, as well as on near future bottlenecks. At the end of the paper the effectiveness of the new methods is tested using a simulation model of a real machining line in the automobile industry.     

Three-dimensional structure of a mutant E.coli aspartate aminotransferase with increased enzymic activity

The aspartate and tyrosine aminotransferases from Escherichiacoli have 43% sequence identity and nearly identical activesites. Both are equally good enzymes for dicarboxylate substrates,but the latter transaminates aromatic amino acids 1000 timesfaster. In an attempt to discover the critical residues forthis differential substrate specificity, the aspartate aminotransferasemutant V39L has recently been prepared. It showed improved k_cal/K_mvalues for aspartate, glutamate and tyrosine and the correspondingoxo acids, mainly due to two to ten times lower K_m values. Forexample, the K_m values of V39L (wild type) for Asp and Glu are0.12 (1.0) and 0.85 (2.7) mM respectively. The mutant was co-crystallizedwith 30 mM maleate from both polyethylene glycol and ammoniumsulfate. Both structures were solved and refined to R-factorsof 0.22 and 0.20 at 2.85 and 2.5 Å resolution respectively.They bear strong resemblance to the closed structure of thewild type enzyme complexed with maleate. The unexpected featureis that, for the first time, the closed form was produced incrystals grown from ammonium sulfate. It is concluded that themutation has shifted the conformational equilibrium towardsthe closed form, which leads to generally reduced substrateK_mS     

ProMeKreis设计指南：用于有利于回用的产品开发的辅助方法

 在BMBF联合计划的ProMeKreis范围内，制订了有利于回用的产品开发方法，它可作为“有利于回用的产品开发的指南”，这一“指南”是一个综合性的辅助方法，有利于产品的整修、改进和使用，其中与给料有关的使用过程的系统研究和优化导致设计过程中的处理方法有显著的改进。