CuxNi1-xO nanostructures and their nanocomposites with reduced graphene oxide: Synthesis,characterization, and photocatalytic applications

NiO nanostructure was synthesized using a simple co-precipitation method and was embedded on reduced graphene oxide surface via ultrasonication. Structural investigations were made through X-ray diffraction (XRD) and functional groups were confirmed by Fourier transform infrared spectroscopy (FTIR). XRD analysis revealed the grain size reduction with doping. Fourier transform infrared spectroscopy confirmed the presence of metal-oxygen bond in pristine and doped NiO nanostructure as well as the presence of carbon containing groups. Scanning electron microscopy (SEM) indicated that the particle size decreased when NiO nanostructure was doped with copper. BET surface area was found to increase almost up to 43 m²/g for Cu doped NiO nanostructure/rGO composite. Current-voltage measurements were performed using two probe method. UV–Visible spectroscopic profiles showed the blue and red shift for Cu doped NiO nanostructure and Cu doped NiO Nanostructure/rGO composite respectively. Rate constant for Cu doped NiO nanostructure/rGO composite found to increase 4.4 times than pristine NiO nanostructure.     

美国珠宝评估业与珠宝保险评估

珠宝首饰的评估在美国的发展也是循序渐进的，依据市场与需求进行的，珠宝评估业的规模正在不断扩大，所提供的服务也正在细化，并向更加专业化的方向发展。     

Copper substituted nickel ferrite nanoparticles anchored onto the graphene sheets as electrode materials for supercapacitors fabrication

Nickel ferrites with high theoretical capacitance value as compared to the other metal oxides have been applied as electrode material for energy storage devices i.e. batteries and supercapacitors. High tendency towards aggregation and less specific surface area make the metal oxides poor candidate for electrochemical applications. Therefore, the improvements in the electrochemical properties of nickel ferrites (NiFe₂O₄) are required. Here, we report the synthesis of graphene nano-sheets decorated with spherical copper substituted nickel ferrite nanoparticles for supercapacitors electrode fabrication. The copper substituted and unsubstituted NiFe₂O₄ nanoparticles were prepared via wet chemical co-precipitation route. Reduced graphene oxide (rGO) was prepared via well-known Hummer's method. After structural characterization of both ferrite (Ni_1-xCu_xFe₂O₄) nanoparticles and rGO, the ferrite particles were decorated onto the graphene sheets to obtain Ni_1-xCu_xFe₂O₄@rGO nanocomposites. The confirmation of preparation of these nanocomposites was confirmed by scanning electron microscopy (SEM). The electrochemical measurements of nanoparticles and their nanocomposites (Ni_0.9Cu_0.1Fe₂O₄@rGO) confirmed that the nanocomposites due to highly conductive nature and relatively high surface area showed better capacitive behavior as compared to bare nanoparticles. This enhanced electrochemical energy storage properties of nanocomposites were attributed to the graphene and also supported by electrical (I-V) measurements. The cyclic stability experiments results showed ~65% capacitance retention after 1000 cycles. However this retention was enhanced from 65% to 75% for the copper substituted nanoparticles (Ni_0.9Cu_0.1Fe₂O₄) and 65–85% for graphene based composites. All this data suggest that these nanoparticles and their composites can be utilized for supercapacitors electrodes fabrication.     

Ionization of high Rydberg states of calcium by electric fields

Abstract

Measurements of electric field ionization of high Rydberg states populated by two-photon excitation are reported. We use a novel technique, in which the extraneous ionization background due to other causes is suppressed, resulting in higher accuracy and sensitivity than otherwise achievable. The method is applied to a series in the calcium spectrum which exhibits an interesting anomaly around n = 63 in previous experiments by laser spectroscopy using thermionic diode detection. In the present experiments, collisions are highly improbable, and it is demonstrated that electric field ionization then occurs without any detectable anomaly around n = 63. The implications of this for the interpretation of the effect are discussed.     

Prevailing wage legislation and public school construction efficiency: a stochastic frontier approach1

Stochastic frontier regression is used to examine the effect of introducing prevailing wage legislation on public school construction efficiency in British Columbia. Prior to the legislation, public school projects were from 16% to 19% smaller, in terms of square feet, than comparable private structures. However, likelihood ratio tests consistently indicate that the coefficients measuring the effect of the policy on the size differential between covered and uncovered projects are not statistically different from zero. These results suggest that construction wage requirements did not alter input utilisation in a way that significantly affected construction output. Average inefficiency for school construction in British Columbia over the period of the study is 12.1%.     

手机电视技术和标准最新进展

手机电视目前已成为手机产业的热门话题,在相关技术日趋成熟、同时一些实验性质的试播计划获得成功的情况下,电信运营商对这项技术的兴趣也越来越高.内嵌手机电视功能的手机量产化之后预计将迅速成为电信运营商的采购重点.本文介绍了手机电视的相关技术、探讨了移动手机电视中所需的零件.     

Xenobiotic Metabolism: The Effect of Acute Kidney Injury on Non-Renal Drug Clearance and Hepatic Drug Metabolism

Acute kidney injury (AKI) is a common complication of critical illness, and evidence is emerging that suggests AKI disrupts the function of other organs. It is a recognized phenomenon that patients with chronic kidney disease (CKD) have reduced hepatic metabolism of drugs, via the cytochrome P450 (CYP) enzyme group, and drug dosing guidelines in AKI are often extrapolated from data obtained from patients with CKD. This approach, however, is flawed because several confounding factors exist in AKI. The data from animal studies investigating the effects of AKI on CYP activity are conflicting, although the results of the majority do suggest that AKI impairs hepatic CYP activity. More recently, human study data have also demonstrated decreased CYP activity associated with AKI, in particular the CYP3A subtypes. Furthermore, preliminary data suggest that patients expressing the functional allele variant CYP3A5*1 may be protected from the deleterious effects of AKI when compared with patients homozygous for the variant CYP3A5*3, which codes for a non-functional protein. In conclusion, there is a need to individualize drug prescribing, particularly for the more sick and vulnerable patients, but this needs to be explored in greater depth.     

Enhanced electrocatalytic performance of cyano groups containing conducting polymer supported catalyst for oxidation of formic acid

A new palladium (Pd) based catalyst was developed using poly(diphenylamine-co-3-aminobenzonitrile) (P(DPA-co-3ABN)) as the new catalyst support. The sizes, distribution and stability of Pd nanoparticles (Pd NPs) are strongly influenced by the cyano group (–CN) present in P(DPA-co-3ABN). Field emission scanning electron microscopy image and energy dispersive x-ray analysis revealed good dispersion of Pd NP onto P(DPA-co-3ABN) matrix. The electrocatalytic activity of P(DPA-co-3ABN)/Pd catalyst electrode (CE) was investigated in terms of formic acid (FA) electro oxidation. The onset potential and catalytic current for the electro oxidation of FA are higher at P(DPA-co-3ABN)/Pd-CE as compared to PdNPs loaded pristine PDPA catalyst electrode (PDPA/Pd-CE). P(DPA-co-3ABN)/Pd-CE exhibited 18 time higher electrocatalytic current than PDPA/Pd-CE for oxidation of FA.     

Antibiotic susceptibility profile of group B streptococcus acquired vertically

OBJECTIVE: To determine the contemporary antibiotic susceptibility profile of vertically acquired group B streptococcal isolates. METHODS: Susceptibility to ampicillin, penicillin G, erythromycin, clindamycin, cefazolin, and gentamicin was assessed by two methods, minimal inhibitory concentration and disc diffusion. RESULTS: The susceptibility profiles of 119 colonizing and eight invasive strains of group B streptococcus isolated from January 1996 to September 1997 at two hospitals in Birmingham, Alabama-University of Alabama at Birmingham and Cooper Green-were studied. Minimal inhibitory concentration determinations indicated that all colonizing strains were susceptible or moderately susceptible to ampicillin and penicillin G. Resistance was noted by at least one strain to each of the other antibiotics; all were resistant to gentamicin, whereas 27 (21%) were resistant to erythromycin, five (4%) to clindamycin, and one (1%) to cefazolin. All of the eight invasive strains were susceptible or moderately susceptible to ampicillin, penicillin G, clindamycin, and cefazolin; one (13%) was resistant to erythromycin, and all were resistant to gentamicin. Disc diffusion results generally were concordant with minimal inhibitory concentration results, although by disc diffusion fewer isolates were classified as susceptible, and more as moderately susceptible, to ampicillin and penicillin G than by minimal inhibitory concentration. CONCLUSION: Universal susceptibility of group B streptococcus to members of the penicillin family supports the continued use of penicillin G or ampicillin for early onset neonatal group B streptococcal disease prevention. For patients allergic to beta-lactam agents, clindamycin (4% resistance) may be a better alternative than erythromycin (21% resistance).     

"Conflicting" motion cues to the visual and vestibular self-motion systems around 0.06 Hz evoke simulator sickness

The basic question this research addressed was, how does simulator sickness vary with simulated motion frequency? Participants were 11 women and 19 men, 20 to 63 years of age. A visual self-motion frequency response curve was determined using a Chattecx posture platform with a VR4 head-mounted display (HMD) or a back-projected dome. That curve and one for vestibular self-motion specify a frequency range in which vestibular and visual motion stimuli could produce conflicting self-motion cues. Using a rotating chair and the HMD, a third experiment supported (p < .01) the hypothesis that conflicting cues at the frequency of maximum "crossover" between the curves (about 0.06 Hz) would be more likely to evoke simulator sickness than would conflicting cues at a higher frequency. Actual or potential applications of this work include a preliminary design guidance curve that indicates the frequency range of simulated motion that is likely to evoke simulator or virtual reality sickness; for simulators intended to operate in this frequency range, appropriate simulator sickness interventions should be considered during the design process.