Don\u27t Bite The Hand That\u27s Feeding You

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Crystal structure of a murine α-class glutathione S-transferase involved in cellular defense against oxidative stress

Glutathione S-transferases (GSTs) are ubiquitous multifunctional enzymes which play a key role in cellular detoxification. The enzymes protect the cells against toxicants by conjugating them to glutathione. Recently, a novel subgroup of α-class GSTs has been identified with altered substrate specificity which is particularly important for cellular defense against oxidative stress. Here, we report the crystal structure of murine GSTA4-4, which is the first structure of a prototypical member of this subgroup. The structure was solved by molecular replacement and refined to 2.9 Å resolution. It resembles the structure of other members of the GST superfamily, but reveals a distinct substrate binding site.

On assessing grindability of recycled and ore-based crankshaft steel: an approach combining data analysis with material science

Material-related grindability variations when grinding recycled and ore-based steel can significantly impair the process efficiency during finishing of automotive crankshafts. To address this problem and to achieve more robust grinding processes, the underlying causes of variation need to be understood. The present work investigates the feasibility of using quality data obtained during production to study grindability variations and identify material-related effects. Analysis of non-destructive inspection protocols indicates steel supplier-dependent differences in grindability. However, no systematic grindability differences between recycled and ore-based steel could be identified. Possible correlations between grindability and material characteristics obtained from supplied steel certificates are discussed

EGF Signal Propagation during C. elegans Vulval Development Mediated by ROM-1 Rhomboid

During Caenorhabditis elegans vulval development, the anchor cell (AC) in the somatic gonad secretes an epidermal growth factor (EGF) to activate the EGF receptor (EGFR) signaling pathway in the adjacent vulval precursor cells (VPCs). The inductive AC signal specifies the vulval fates of the three proximal VPCs P5.p, P6.p, and P7.p. The C. elegans Rhomboid homolog ROM-1 increases the range of EGF, allowing the inductive signal to reach the distal VPCs P3.p, P4.p and P8.p, which are further away from the AC. Surprisingly, ROM-1 functions in the signal-receiving VPCs rather than the signal-sending AC. This observation led to the discovery of an AC–independent activity of EGF in the VPCs that promotes vulval cell fate specification and depends on ROM-1. Of the two previously reported EGF splice variants, the longer one requires ROM-1 for its activity, while the shorter form acts independently of ROM-1. We present a model in which ROM-1 relays the inductive AC signal from the proximal to the distal VPCs by allowing the secretion of the LIN-3L splice variant. These results indicate that, in spite of their structural diversity, Rhomboid proteins play a conserved role in activating EGFR signaling in C. elegans, Drosophila, and possibly also in mammals

Physics-based approach for predicting dissolution‒diffusion tool wear in machining

A new approach is proposed to predict the thermally-activated dissolution-diffusion wear of carbide tools. Departing from the iterative procedure used for such nonlinear processes, a direct response surface approach that correlates the cutting conditions and wear level to the interface temperature is presented. For prediction of wear evolution, a calibrated thermodynamic model that describes chemical interaction between the tool and workpiece materials is combined with the FE simulation of machining process, considering the pressure-dependent thermal constriction resistance phenomenon. The accuracy of predicting flank wear in turning C50 plain carbon steel ‒ where dissolution-diffusion wear mechanism prevails ‒ is validated experimentally

On mechanics and monitoring of plunge-roll rotary dressing of grinding wheels

A study is made into the mechanics and monitoring of rotary plunge-roll dressing of grinding wheels using a roll with multi-layer diamonds contained in a hybrid, metal-ceramic bond. A fundamental relationship is obtained between grinding/dressing specific energy and the dressing aggressiveness number Aggrd, revealing a distinct size effect. Results also indicate (i) a nearly linear relationship between grinding and dressing specific energy, and (ii) direct proportionality between dressing specific energy and the acoustic emission (AE) signal. SEM observations indicate that smaller Aggrd produces a grit-dulling phenomenon different from grinding-induced dulling of the grits by attrition, which causes rapid workpiece-material adhesion

The faradaic efficiency of the lithium-thionyl chloride battery

The efficiency of converting chemical energy into electrical energy has been studied for the case of D-size, low and medium rate lithium-thionyl chloride (Li/TC) cells, under DC and various pulsed loads. Microcalorimetric monitoring of the heat output during discharge allowed the direct measurement of the faradaic efficiency, and showed that self-discharge is far more pervasive than previously acknowledged by researchers and battery manufacturers. Evaluations of the cell dynamics prove that current load and temperature fluctuations combine to disrupt the lithium passivation and to greatly enhance self-discharge. Typical faradaic efficiencies for DC range from abut 30% at low current density to 90% at moderate and 75% at high current density. Pulsed current further depresses these efficiency levels, except at very low average current densities. The decreased faradaic efficiency of Li/TC batteries in certain pulse situations needs to be studied further to define the range of applications for which it can be successfully used

Monitoring protocol to assess the overall performance of lighting and daylighting retrofit projects

In the field of lighting and daylighting, standard monitoring procedures to assess the overall performance of retrofit projects are scarce. Nevertheless the access to monitored data is crucial to assess whether daylighting or electric lighting systems deliver the expected performance in terms of cost-effectiveness and energy efficiency. In order to bridge this gap, a monitoring protocol is under development as part of the International Energy Agency – Solar Heating and Cooling Programme (IEA-SHC) Task 50 ‘Advanced Lighting Solutions for Retrofitting Buildings’. The protocol focuses on lighting and/or daylighting (façade or roof) retrofit in the non-residential building stock. It covers four key aspects: energy efficiency, costs, quality of the lighting environment and user satisfaction. The main features of this protocol are presented in this paper, along with some lessons learned from the ongoing application on selected case studies