Compositional changes in

The compositional changes in Al-Li-(Mg)-(Cu) alloys induced by oxidation at high temperature (450 °C to 570 °C) were investigated by secondary ion mass spectrometry (SIMS). It was found that the alloy surface beneath the oxide layer was depleted in both Li and Mg as a consequence of the selective oxidation of these elements, whereas Cu concentration was nearly constant or slightly increased in the affected zone. The measured-concentration profiles of Li and Mg were modeled using a diffusion equation to obtain diffusion data for the alloys. The depletion profiles also provided information regarding the interfacial-alloy composition and the depletion depth. The effect of alloying elements on the oxidation and depletion behavior is discussed. Secondary ion mass spectrometry data were quantified using the relative sensitivity factor method, and the quantification procedure is described in detail.     

Knockouts of Se-glutathione peroxidase-1 and Cu,Zn superoxide dismutase exert different impacts on femoral mechanical performance of growing mice

The objective of this study was to determine the impact of knockout of Cu,Zn-superoxide dismutase (SOD1) and Se-glutathione peroxidase-1 (GPX1) on murine bone biomechanical properties. Femora samples were collected from wild-type (WT), SOD1-knockout [SOD1(-/-)] and GPX1-knockout [GPX1(-/-)] female mice (9-wk old, n = 7-8 per genotype) to assay for bone enzyme activities and mechanical properties in three point bending. Prior to testing, all mice were fed a torula yeast diet supplemented with 0.4 mg Se/kg as sodium selenite. Compared with the WT mice, SOD1(-/-) mice displayed a series of reductions (p < 0.05): 24% in body mass, 8% in femoral length, 43% in femoral structural strength, and 32% in bending stiffness. When differences in body size were accounted for, femoral failure moment in SOD1(-/-) mice remained lower (p < 0.05) than that of WT. Femoral tartrate resistant acid phosphatase activity in SOD1(-/-) was 47% greater (p < 0.05) than the WT. In contrast, GPX1(-/-) mice showed no significant differences in femoral mechanical properties from those of WT mice. In conclusion, knockout of SOD1 exerted a greater impact on femoral mechanical characteristics than that of GPX1 in growing mice.     

Developing an Antibody–Drug Conjugate Approach to Selective Inhibition of an Extracellular Protein

Antibody–drug conjugates (ADCs) are a growing class of therapeutics that harness the specificity of antibodies and the cell-killing potency of small-molecule drugs. Beyond cytotoxics, there are few examples of the application of an ADC approach to difficult drug discovery targets. Here, we present the initial development of a non-internalising ADC, with a view to selectively inhibiting an extracellular protein. Employing the wellinvestigated matrix metalloproteinase-9 (MMP-9) as our model, we adapted a broad-spectrum, nonselective MMP inhibitor for conjugation and linked this to a MMP-9-targeting antibody. The resulting ADC fully inhibits MMP-9, and ELISA results suggest antibody targeting can direct a nonselective inhibitor.     

Bandlike transport in strongly coupled and doped quantum dot solids: a route to high-performance thin-film electronics

We report bandlike transport in solution-deposited, CdSe QD thin-films with room temperature field-effect mobilities for electrons of 27 cm(2)/(V s). A concomitant shift and broadening in the QD solid optical absorption compared to that of dispersed samples is consistent with electron delocalization and measured electron mobilities. Annealing indium contacts allows for thermal diffusion and doping of the QD thin-films, shifting the Fermi energy, filling traps, and providing access to the bands. Temperature-dependent measurements show bandlike transport to 220 K on a SiO(2) gate insulator that is extended to 140 K by reducing the interface trap density using an Al(2)O(3)/SiO(2) gate insulator. The use of compact ligands and doping provides a pathway to high performance, solution-deposited QD electronics and optoelectronics.     

Simultaneous line center and linewidth measurement using dual frequency modulation spectroscopy

We propose a method to simultaneously measure the center frequency of a spectral feature and the frequency linewidth of the feature. The method relies on dual frequency modulation of a carrier frequency, which probes the spectral feature, and phase sensitive detection of the transmitted signal at the two modulation frequencies. The detected signals provide two servo-stabilization signals for frequency control of the carrier frequency to the resonance line center and one of the modulation frequencies to the resonance linewidth.     

The effect of extreme temperature in an oxidising atmosphere on dense tantalum carbide (TaC)

This study describes the microstructure development as dense tantalum carbide (TaC), which is subjected to extreme temperature environments (3,000 °C) in the presence of oxygen. These are conditions that structural materials are expected to experience in hypersonic aero-propulsion applications. The conditions produce molten oxide which may provide a temporary resistance to rapid oxidation and may go some way to repair thermal shock cracks, however, at the same time the liquid is observed to attack the dense ceramic both chemically and mechanically. A reaction mechanism is suggested which involves dissolution of TaC in the oxide melt and a two step oxidation; first the reaction of TaC with oxygen to form Ta(O,C) and TaO _x , resulting in dissolved dissociated carbon, followed by the reaction of dissolved carbon with oxygen to produce gas. This microstructural analysis of one of the candidate ultra-high temperature ceramic materials for hypersonic flight provides new insight into the mechanism of TaC oxidation and the role of the liquid oxide layer in acting not only as a protective layer to further oxidation, as is commonly reported, but also as a dynamic component that promotes erosion of the TaC surface and is a source of further oxygenation of the TaC surface. If the formation of the liquid phase can be better controlled and the reaction of the liquid phase with the matrix be slowed and stabilised, then the formation of a liquid phase at the surface of TaC may provide a key to designing materials that can withstand the rigours of hypersonic flight.     

Flexibly Monitoring Group Sequential Survival Trials When Testing is Based Upon a Weighted Log-Rank Statistic

Abstract

We consider the repeated group sequential testing of a survival endpoint with a time-varying treatment effect using a weighted log-rank statistic. The emphasis of this article is on the monitoring of this statistic where information growth is nonlinear. We propose using a constrained boundaries approach to maintain the planned operating characteristics of a group sequential design. A simulation study is presented to demonstrate the operating characteristics of the method together with a case study to illustrate the procedure. We show that when monitoring a weighted log-rank statistic, the entry and survival distribution needs to be estimated at interim analyses.     

Relationships between protein and other chemical composition and texture of tofu made from soybeans grown in different locations

Understanding quantitative relationships between protein and other chemical components in diverse soybean genotypes (lines) grown in different locations and the firmness of tofu can provide scientific insight for selecting soybean suitable for tofu making. Locations showed significant effects on seed components, including total protein, major storage proteins, subunits and polypeptides of the major storage proteins, and calcium, but not magnesium or phytic acid. Results showed that 11S content, but not 11S/7S ratio, was only correlated with filled tofu firmness when analyzed over all locations. A strong and positive correlation between firmness and A₃ polypeptide of the 11S protein content was found for both pressed tofu (r = 0.80, p < 0.001) and filled tofu (r = 0.76, p < 0.001) over three locations (overall pooled data) and within most individual locations. The correlation of filled tofu firmness and A₃ polypeptide was significant for each of the three individual locations. However, the correlation of pressed tofu firmness and A₃ polypeptide content was significant at two of three locations. Mean calcium content was positively correlated with mean pressed and filled tofu firmness over all locations, but calcium was not correlated with pressed tofu firmness at any individual location, and only one location showed a significant correlation of calcium and filled tofu firmness. In addition, pressed tofu firmness was found to be negatively correlated with tofu yield. The findings that A₃ polypeptide's strong relationship with tofu firmness within certain locations may be used by the food industry to select proper soybean for manufacturing tofu and to facilitate tofu soybean breeding for tofu making.     

Traumatic brain injury and posttraumatic stress disorder: a preliminary investigation of neuropsychological test results in PTSD secondary to motor vehicle accidents

In the present investigation involvement of endothelial-derived reactive oxygen species (ROS) and their interaction with nitric oxide (NO), during norepinephrine (NE)-induced contraction of rat aortic rings was studied. NE (1x10(-10) M to 1x10(-5) M) caused concentration-dependent contractio n of the endothelium intact aortic rings. In the presence of hydroxyl radical scavengers, histidine (1x10(-3) M), mannitol (3x10(-3) M), dimethyl sulfoxide (50x10(-3) M) or thiourea (1x10(-3) m), superoxide dismutase (superoxide radical scavenger, SOD 10 or 100 U ml-1) or catalase (hydrogen peroxide inactivator 3, 10, or 100 U ml-1) the concentration-response curve of NE was shifted towards the right. Interestingly, in NG-nitro-l-arginine methyl ester (L-NAME) (1x10(-5) M, a NO synthase inhibitor) pretreated rings, NE-induced contractions were not inhibited by SOD or extracellular hydroxyl radical scavengers (mannitol and histidine). However, in these rings NE-induced contractions were found to be attenuated by endogenous hydroxyl radical scavengers (thiourea and DMSO) or catalase. In the endothelium denuded rings no significant effect of these scavengers on NE-induced contractions was observed. These results thus indicate the involvement of endothelium-derived hydrogen peroxide, superoxide and hydroxyl radicals in the NE-induced contractions. In addition, endothelial NO interacts with the ROS generated during rat aortic ring contractions.     

Surveillance and investigation of homicides at work: California fatality assessment and control evaluation program

The authors describe California's Fatality Assessment and Control Evaluation program, a state-based surveillance and investigation program for traumatic occupational fatalities. FACE has identified occupational homicides as a priority for targeted prevention efforts to reduce the incidence of work-related fatalities.