Biological functionalization of the amine-terminated Si(100) surface by glycine

A peptide reaction of glycine on an amine-terminated Si(100) surface was investigated using C 1s, N 1s, O 1s, and Si 2p core-level spectroscopy, where the amine-terminated Si(100) surface was prepared using NH₃. In-situ thermal treatments at a mild temperature of 50 °C after the adsorption of glycine on a room-temperature amine-terminated Si(100) surface induced the peptide reaction between the carboxyl group of glycine and the amine group of the surface. This suggests that the amine-terminated Si(100) surface can be an excellent template for constructing a junction between a biomaterial and a Si surface using a dry process.     

Reputation and efficiency: A non-parametric assessment of America’s top-rated MBA programs

Widely publicized reports of fresh MBAs getting multiple job offers with six-figure annual salaries leave a long-lasting general impression about the high quality of selected business schools. While such spectacular achievement in job placement rightly deserves recognition, one should not lose sight of the resources expended in order to accomplish this result. In this study, we employ a measure of Pareto-Koopmans global efficiency to evaluate the efficiency levels of the MBA programs in Business Week’s top-rated list. We compute input- and output-oriented radial and non-radial efficiency measures for comparison. Among three tier groups, the schools from a higher tier group on average are more efficient than those from lower tiers, although variations in efficiency levels do occur within the same tier, which exist over different measures of efficiency.     

厚尾相依序列的均值变点估计

本文研究了厚尾相依序列的均值变点估计. 证明了变点的CUSUM估计的一致性并得到了收敛速度.在方差无穷的情况下推广了H\'{a}jek--R\'{e}nyi不等式.     

Phase conjugator with two coherent beams in a BaTiO3:Ce crystal

A phase conjugator which includes two coherent beams that are incident upon one of a-faces of a BaTiO3:Ce crystal without internal reflection is performed experimentally. Based on the four-wave mixing, the mechanism of this conjugator is investigated numerically. In comparison with the corresponding self-pumped phase conjugator, the phase-conjugate behavior of this conjugator is established much more quickly, its phase conjugate reflectivity is greater in some cases and the intensity threshold is lower by over two orders of magnitude. The configuration of this conjugator is easy to perform because the output response exists over a wide range of angular and lateral positions of the two incident beams on the crystal.     

Electrochemical behavior of dopamine and ascorbic acid at osmium(II) complex cationic monolayer modified gold electrodes.

The electrooxidation of dopamine (DA) and ascorbic acid (AA) was studied using gold electrodes modified by a cationic self-assembled monolayer of [Os(bpy)2(bpy-(CH2),3SH)]2+ by cyclic voltammetry. At an [Os(bpy)2(bpy-(CH2)13SH)]2+/Au electrode, the oxidation peak of DA shifted to a much more positive potential as compared with that of a bare gold electrode, while the oxidation peak potential of AA showed a slightly negative shift due to their different electrostatic interactions with the cationic monolayer. Thus, a sufficient potential difference was achieved for distinguishing the electrochemical responses of DA and AA. However, when CH3(CH2)11SH was mixed into the cationic monolayer, the enhanced packing of the mixed monolayer blocked the access of DA or AA to the electrode, resulting in further positive shifts for both oxidation-peak potentials.     

Enhanced spin–orbit torque efficiency in Pt100−xNix alloy based magnetic bilayer

The binary alloy/ferromagnetic metal heterostructure has drawn extensive attention in the research field of spin–orbittorque(SOT)due to the potential enhancement of SOT efficiency via composition engineering.In this work,the magneticproperties and SOT efficiency in the Pt100?xNix/Ni78Fe22 bilayers were investigated via the spin-torque ferromagneticresonance(ST-FMR)technique.The effective magnetic anisotropy field and effective damping constant extracted by analyzing the ST-FMR spectra show a weak dependence on the Ni concentration.The effective spin-mixing conductanceof 8.40×10¹⁴??1·m?2and the interfacial spin transparency Tin of 0.59 were obtained for the sample of Pt70Ni30/NiFebilayer.More interestingly,the SOT efficiency that is carefully extracted from the angular dependence of ST-FMR spectrashows a nonmonotonic dependence on the Ni concentration,which reaches the maximum at x=18.The enhancement ofthe SOT efficiency by alloying the Ni with Pt shows potential in lowering the critical switching current.Moreover,alloyingrelatively cheaper Ni with Pt may promote to reduce the cost of SOT devices.     

A Simplified Optimal Control Method for Homoclinic Bifurcations

A simplified optimal control method is presented for controlling or suppressing homoclinic bifurcations of general nonlinear oscillators with one degree-of-freedom. The simplification is based on the addition of an adjustable parameter and a superharmonic excitation in the force term. By solving an optimization problem for the optimal amplitude coefficients of the harmonic and superharmonic excitations to be used as the controlled parameters, the force term as the controller can be designed. By doing so, the control gain and small optimal amplitude coefficients can be obtained at lowest cost. As the adjustable parameter decreases, a gain of some amplitude coefficient ratio is increased to the highest degree, which means that the region where homoclinic intersection does not occur will be enlarged as much as possible, leading to the best possible control performance. Finally, it is shown that the theoretical analysis is in agreement with the numerical simulations on several concerned issues including the identification of the stable and unstable manifolds and the basins of attraction.     

Enhancement of CO2 sorption uptake on hydrotalcite by impregnation with K2CO3

The awareness of symptoms of global warming and its seriousness urges the development of technologies to reduce greenhouse gas emissions. Carbon dioxide (CO(2)) is a representative greenhouse gas, and numerous methods to capture and storage CO(2) have been considered. Recently, the technology to remove high-temperature CO(2) by sorption has received lots of attention. In this study, hydrotalcite, which has been known to have CO(2) sorption capability at high temperature, was impregnated with K(2)CO(3) to enhance CO(2) sorption uptake, and the mechanism of CO(2) sorption enhancement on K(2)CO(3)-promoted hydrotalcite was investigated. Thermogravimetric analysis was used to measure equilibrium CO(2) sorption uptake and to estimate CO(2) sorption kinetics. The analyses based on N(2) gas physisorption, X-ray diffractometry, Fourier transform infrared spectrometry, Raman spectrometry, transmission electron microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy were carried out to elucidate the characteristics of sorbents and the mechanism of enhanced CO(2) sorption. The equilibrium CO(2) sorption uptake on hydrotalcite could be increased up to 10 times by impregnation with K(2)CO(3), and there was an optimal amount of K(2)CO(3) for a maximum equilibrium CO(2) sorption uptake. In the K(2)CO(3)-promoted hydrotalcite, K(2)CO(3) was incorporated without changing the structure of hydrotalcite and it was thermally stabilized, resulting in the enhanced equilibrium CO(2) sorption uptake and fast CO(2) sorption kinetics.     

Magnetic bead-based approach to monitoring of cigarette smoke-induced DNA oxidation damage and screening of natural protective compounds

Cigarette smoking can damage DNA and induce spontaneous mutagenesis or carcinogenesis. Here, we describe a novel strategy for in situ monitoring of cigarette smoke-induced DNA oxidation damage and offer a method for screening natural compounds that protect DNA against tobacco smoke. The present protocol takes advantage of a fast and simple magnetic separation/mixing method and a highly sensitive chemiluminescence (CL) ELISA. The DNA immobilized on the magnetic beads was oxidized by the smoke in the absence or presence of natural compounds, and then oxidative DNA was conveniently held by magnetic force, whereas the complex tobacco smoke matrix and any remaining compounds were completely eliminated by extensive washing, and possible interferences were thus removed and oxidative damage was then sensitively monitored by CL ELISA. A library of 32 natural products was then screened and three were found to protect DNA from oxidative damage and thus may be promising compounds for the development of new drugs. Moreover, the protection effect of these three natural compounds against DNA oxidation damage was successfully classified by directly spiking them in the reference cigarettes. In addition, the potential to screen a mixture in a complex sample matrix, such as crude extracts, was also demonstrated, and hence the proposed technique can screen compounds within a complex matrix and enhance the screening throughput.