女性掌握某些科技产品使用权

在某些科技产品的使用过程中,美国女性的主导权超过男人,比如观看电视节目、DVR使用、浏览社会类媒体网站,甚至是打游戏。这个调查结果是由Solution Research Group发布的一个新的、关于"女性和数字生活方式"报告发布的。     

A longitudinal elasticity study of hair from the human head in forensic medicine

A rapid and sensitive method for assessing hair keratin stretch elasticity modulus has been developed. The technique is based on measuring the oscillation resonance frequency of hair fragments fixed at one end. The first results indicate a high sensitivity of the method and the possibility of its use in forensic medicine.     

High-performance 0.07-μm CMOS with 9.5-ps gate delay and 150 GHzfT

We report room-temperature 0.07-μm CMOS inverter delays of 13.6 ps at 1.5 V and 9.5 ps at 2.5 V for an SOI substrate; 16 ps at 1.5 V and 12 ps at 2.5 V for a bulk substrate. This is the first room-temperature sub-10 ps inverter ring oscillator delay ever reported. PFETs with very high drive current and reduction in parasitic resistances and capacitances for both NFETs and PFETs, realized by careful thermal budget optimization, contribute to the fast device speed. Moreover, the fast inverter delay was achieved without compromising the device short-channel characteristics. At V_dd=1.5 V and I_off ~2.5 nA/μm, minimum L_eff is about 0.085 μm for NFETs and 0.068 μm for PFETs. PFET I_on is 360 μA/μm, which is the highest value ever reported at comparable V_dd and I_off. The SOI MOSFET has about one order of magnitude higher I_off than a bulk MOSFET due to the floating-body effect. At around 0.07 μm L_eff, the NFET cut-off frequencies are 150 GHz for SOI and 135 GHz for bulk. These performance figures suggest that subtenth-micron CMOS is ready for multi-gigahertz digital circuits, and has good potential for RF and microwave applications     

Cubic Phase GaN on Nano‐grooved Si (100) via Maskless Selective Area Epitaxy

A method of forming cubic phase (zinc blende) GaN (referred as c‐GaN) on a CMOS‐compatible on‐axis Si (100) substrate is reported. Conventional GaN materials are hexagonal phase (wurtzite) (referred as h‐GaN) and possess very high polarization fields (～MV/cm) along the common growth direction of <0001>. Such large polarization fields lead to undesired shifts (e.g., wavelength and current) in the performance of photonic and vertical transport electronic devices. The cubic phase of GaN materials is polarization‐free along the common growth direction of <001>, however, this phase is thermodynamically unstable, requiring low‐temperature deposition conditions and unconventional substrates (e.g., GaAs). Here, novel nano‐groove patterning and maskless selective area epitaxy processes are employed to integrate thermodynamically stable, stress‐free, and low‐defectivity c‐GaN on CMOS‐compatible on‐axis Si. These results suggest that epitaxial growth conditions and nano‐groove pattern parameters are critical to obtain such high quality c‐GaN. InGaN/GaN multi‐quantum‐well structures grown on c‐GaN/Si (100) show strong room temperature luminescence in the visible spectrum, promising visible emitter applications for this technology.     

Superoxide dismutase mimetics inhibit neutrophil-mediated human aortic endothelial cell injury in vitro

In this study, we evaluated the ability of low molecular weight manganese-based superoxide dismutase mimetics to attenuate neutrophil-mediated oxygen radical damage to human aortic endothelial cells in vitro. Human neutrophils, when exposed to tumor necrosis factor-alpha and the complement compound C5a, induced endothelial damage assessed by the release of 51Cr into the medium. This damage correlated with the amount of superoxide generated by neutrophils. Three superoxide dismutase mimetics, with catalytic rate constants for superoxide dismutation ranging from 4 to 9 x 10(7) M-1 S-1, inhibited neutrophil- or xanthine oxidase-mediated endothelial cell injury in a concentration-dependent manner. A similar manganese-based compound with no detectable superoxide dismutase activity was ineffective in inhibiting injury. Fluorescent studies of the neutrophil respiratory burst showed that the superoxide dismutase mimetics were protective without interfering with the generation of superoxide by activated neutrophils. Catalase, elastase inhibitors, and desferrioxamine mesylate (an iron chelator and hydroxyl radical scavenger) were not protective against cell injury. This investigation demonstrates that neutrophil-mediated human aortic endothelial cell injury in vitro is mediated by the superoxide anion and that low molecular weight manganese-based superoxide dismutase mimetics are effective in abrogating this damage.     

Hormonal regulation of an islet-specific enhancer in the pancreatic homeobox gene STF-1

The homeobox protein STF-1 appears to function as a master control switch for expression of the pancreatic program during development. Here we characterize a composite enhancer which directs STF-1 expression to pancreatic islet cells via two functional elements that recognize the nuclear factors HNF-3beta and BETA-2. In keeping with their inhibitory effects on islet cell maturation, glucocorticoids were found to repress STF-1 gene expression by interfering with HNF-3beta activity on the islet-specific enhancer. Overexpression of HNF-3beta suppressed glucocorticoid receptor-mediated inhibition of the STF-1 gene, and our results suggest that the expansion of pancreatic islet precursor cells during development may be restricted by hormonal cues which regulate STF-1 gene expression.     

Constrained multi-item inventory systeṁs an implicit approach

This paper examines the N-item deterministic inventory model subject to a single linear constraint. Functional relationships between the Lagrangian multipliers and shifts occurring simultaneously in multiple system parameters are identified and used to establish effective initial bounds on the optimal multiplier, Φ^*, in closed form. A recursive process which rapidly converges to Φ^* is also presented. Finally, a comparative analysis highlighting the efficiency of the proposed process in relation to existing algorithms is exhibited.     

Electrodeposition of copper on copper in the presence of dithiothreitol

Studies of the -SH group effect present in dithiothreitol (DTE) with respect to morphology and electrode kinetics of copper electrodeposits on the (1 1 1) plane of a copper single crystal and polycrystalline copper from highly purified solutions of acidified copper sulphate were made. At 2.0 and 5.0 mA cm^–2 there was a truncation of pyramids to layers and ridges and then to polycrystalline growth with an increase in the concentration of DTE in the bath. At higher current densities the change was from pyramids to thin hexagonal blocks, dragged pyramids and then to polycrystalline growth. Interestingly, the above morphological changes repeated at two different concentrations of DTE corresponding to two -SH groups present in the molecule. Levelling of the grains was observed at all current densities studied on a polycrystalline substrate. The electrode kinetic parameters have been correlated with the morphological changes and transport mechanisms have been proposed for different concentrations of the additive.