Reconstitution of a protein disulfide catalytic system

Disulfide bonds are important for the structure and stability of many proteins. In prokaryotes their formation is catalyzed by the Dsb proteins. The DsbA protein acts as a direct donor of disulfides to newly synthesized periplasmic proteins. Genetic evidence suggests that a second protein called DsbB acts to specifically reoxidize DsbA. Here we demonstrate the direct reoxidation of DsbA by DsbB. We have developed a fluorescence assay that allows us to directly follow the reoxidation of DsbA. We show that membranes containing catalytic amounts of DsbB can rapidly reoxidize DsbA to completion. The reaction strongly depends on the presence of oxygen, implying that oxygen serves as the final electron acceptor for this disulfide bond formation reaction. Membranes from a dsbB null mutant display no DsbA reoxidation activity. The ability of DsbB to reoxidize DsbA fits Michaelis-Menten behavior with DsbA acting as a high affinity substrate for DsbB with a Km = 10 microM. The in vitro reconstitution described here is the first biochemical analysis of DsbB and allows us to study the major pathway of disulfide bond formation in Escherichia coli.     

Effects of social power on aspiration setting and striving.

"Individual Ss were observed in a situation similar to the one used by Rotter (1942) for studying the level of aspiration, while they were to perceive themselves as members of a team which was not physically present. In two experimental conditions… the Ss were provided standards of individual performance, for a series of trials, said to originate in others members of their team. Events were so arranged that Ss… did not attain the performance levels put before them by the others… . Assumptions were made that: (a) scores are evaluated in terms of internal levels of aspiration; (b) referent social pressures more strongly influence… internal levels of aspiration than do coercive… and (c) a discrepancy between an internal level of aspiration and an obtained score generates forces to reduce this discrepancy." Results confirmed the hypotheses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pressure-density-temperature measurements of ethylene

As a contribution to current projects on the thermophysical properties of ethylene for the preparation of reference tables, measured PVT data are presented. For the measurements in the single-phase region, two types of equipment have been employed: an expansion apparatus to determine isotherms and a constant volume apparatus to determine isochores. Both the design and calibration of each type of equipment and the experimental procedures are described. The accuracy of the 251 measured PVT data on 10 isotherms and 16 isochores, which cover the temperature range from –30 to 80C, with pressures up to 250 bar, is about 0.1% in the compressibility factors. The critical temperature was determined with the result t _c =9.22±0.02C by visual observation of the disappearance of the meniscus.     

How does the way a weight is carried affect spinal loads?

People often have to carry a weight which increases the spinal load. Few in vivo measured spinal loading data exist for carrying a weight. The aim of this study was to measure the force increase on a vertebral body replacement (VBR) caused by carrying weights in different ways. A telemeterised VBR allowing the measurement of six load components was implanted in five patients suffering from lumbar vertebral body fractures. The patients carried different weights laterally in one or both hands, in front of the body and in a backpack. The force increase with respect to standing was more than twice as high for carrying a weight in front of the body compared with carrying it laterally. A weight of 10 kg in a backpack led to an average force increase of only 35 N. The position of the carried weight relative to the spine strongly affected the spinal load.     

The autonomy-safety-paradox of service robotics in Europe and Japan: a comparative analysis

Service and personal care robots are starting to cross the threshold into the wilderness of everyday life, where they are supposed to interact with inexperienced lay users in a changing environment. In order to function as intended, robots must become independent entities that monitor themselves and improve their own behaviours based on learning outcomes in practice. This poses a great challenge to robotics, which we are calling the “autonomy-safety-paradox” (ASP). The integration of robot applications into society requires the reconciliation of two conflicting aspects: increasing machine autonomy and ensuring safety in end-use. As the level of robot autonomy grows, the risk of accidents will increase, and it will become more and more difficult to identify who is responsible for any damage incurred. However, emphasizing safety impairs the autonomous functioning of the robot. This problem implies the need for a broadened concept of product safety. Our comparative study shows that the institutional framing of the ASP as well as concrete solutions to this problem differs between Europe and Japan in two respects: (1) the understanding of robot agency and (2) the concept of “appropriate” user–robot interaction.     

Interfacial mechanical behavior of 3D printed ABS

We describe an experimental approach for characterizing the local mechanical behavior of acrylonitrile butadiene styrene (ABS) structures processed through fused deposition modeling. ABS test specimens processed in various build orientations were subject to multiscale mechanical tests as well as local morphology and chemical analyses. Instrumented indentation, local dynamic mechanical analysis, and atomic force microscopy tests were used to explore the mechanical behavior and morphology of build surfaces and weld interfaces. An interfacial stiffening effect was found for the majority of the specimens tested, with up to a 40% increase in the indentation elastic modulus measured with respect to the build surfaces. Raman spectroscopy mapping of the interfacial areas revealed ～30% less butadiene/styrene and butadiene/acrylonitrile ratios with respect to analysis of the build surfaces. The results provide insight into the multiscale behavior of additive manufactured structures and offer the potential to guide processing–structure–property understanding of these materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43671.     

Toward neuroadaptive support technologies for improving digital reading: a passive BCI-based assessment of mental workload imposed by text difficulty and presentation speed during reading

User Modeling and User-Adapted Interaction - We investigated whether a passive brain–computer interface that was trained to distinguish low and high mental workload in the...     

Saccharomyces cerevisiae Gle2/Rae1 is involved in septin organization,essential for cell cycle progression

Gle2/Rae1 is highly conserved from yeast to humans and has been described as an mRNA export factor. Additionally, it is implicated in the anaphase‐promoting complex‐mediated cell cycle regulation in higher eukaryotes. Here we identify an involvement for Saccharomyces cerevisiae Gle2 in septin organization, which is crucial for cell cycle progression and cell division. Gle2 genetically and physically interacts with components of the septin ring. Importantly, deletion of GLE2 leads to elongated buds, severe defects in septin‐assembly and their cellular mislocalization. Septin‐ring formation is triggered by the septin‐regulating GTPase Cdc42, which establishes and maintains cell polarity. Additionally, activity of the master cell cycle regulator Cdc28 (Cdk1) is needed, which is, besides other functions, also required for G₂/M‐transition, and in yeast particularly responsible for initiating the apical–isotropic switch. We show genetic and physical interactions of Gle2 with both Cdc42 and Cdc28. Most importantly, we find that gle2? severely mislocalizes Cdc42, leading to defects in septin‐complex formation and cell division. Thus, our findings suggest that Gle2 participates in the efficient organization of the septin assembly network, where it might act as a scaffold protein. © 2017 The Authors. Yeast published by John Wiley & Sons, Ltd.