Direct laser writing of μ-chips based on hybrid C–Au–Ag nanoparticles for express analysis of hazardous and biological substances

Micro-chips based on organic–inorganic hybrid nanoparticles (NPs) composed of nanoalloys of gold (Au) and silver (Ag) embedded in an amorphous carbonaceous matrix (C–Au–Ag NPs) were prepared directly on a substrate by the laser- induced deposition (for short: LID) method. The C–Au–Ag NPs show a unique plasmon resonance which enhances Raman scattering of analytes, making the μ-chips suitable to detect ultra-low-volumes (10−12 liter) and concentrations (10−9 M) of bio-agents and a hazardous compound. These micro-chips constitute a novel, flexible solid-state device that can be used for applications in point-of-care diagnostics, consumer electronics, homeland security and environmental monitoring

Isolation of renal brush-border membrane vesicles by a low-speed centrifugation; effect of sex hormones on Na⁺-H⁺ exchange in rat and mouse kidney

Na+-H+ exchange in rat and mouse renal brush-border membrane vesicles was studied by fluorescence quenching of the ΔpH indicator, acridine orange. Brush-border membrane vesicles were isolated by a modified Mg/EGTA-precipitation method at low speed centrifugation (8000 × g). The enzymatic characteristics of these membrane vesicles were similar to those obtained by the original high-speed centrifugation method (Biber et al. (1981) Biochim. Biophys. Acta, 647, 169–176). The rates of Na+-H+ exchange in renal brush-border membrane vesicles from male and female rats were similar. Neither ovariectomy nor treatment of ovariectomized rats with estradiol or testosterone changed the activity of Na+-H+ exchanger. The rates of Na+-H+ exchange in the mouse were smaller than in the rat indicating the existence of species differences. Na+-H+ exchange in mouse renal brush-border membranes exhibit strong sex differences, the rates in the male being higher than in the female. Castration of male mice led to a decrease in Na+-H+ exchanges to values found in females. Treatment of castrated mice with estradiol had no effect. In contrast, treatment with testosterone increased the rat of the exchanger by more than 100%. The effect of testosterone was restricted to the Vmax of the Na+-H+ exchanger, whereas the apparent Km for Na+ remained unchanged. Na+-dependent d-glucose transport in mouse renal luminal membranes exhibited also sex differences due to the potent stimulatory effect of testosterone. Therefore, Na+-H+ exchange and Na+-dependent d-glucose transport in the mouse kidney are under control of androgen hormones. This effect could be in close connection with the wellknown renotropic action of androgens in the mouse

Systematic tuning of segmented magnetic nanowires into three-dimensional arrays of 'bits'

A method is presented for the preparation of a three-dimensional magnetic data storage material system. The major ingredients are an inert nanoporous matrix prepared by anodization and galvanic plating of magnetic and non-magnetic metals in wire shape inside the cylindrical pores. The individual nanomagnets consist of a nickel-cobalt alloy, the composition of which is tuned systematically by adjusting the electrolytic bath composition at one optimal applied potential. The lowest magnetocrystalline anisotropy is obtained at the composition Ni60Co40, as quantified by superconducting quantum interference device magnetometry. Wires of this composition experience a pinning-free propagation of magnetic domain walls, as determined by single-wire magneto-optical Kerr effect magnetometry. Adding copper into the electrolyte allows one to generate segments of Ni60Co40 separated by non-magnetic copper. The segment structure is apparent in individual nanowires imaged by scanning electron microscopy, UV-photoelectron emission microscopy, and transmission electron microscopy. The single-domain structure of the wire segments is evidenced by magnetic force microscopy

Medical teachers' attitudes towards science and motivational orientation for medical research

BACKGROUND: Research is an important motivating factor for pursuing a career in academic medicine, but the relation between motivation and other factors involved in scientific research are not clear. ----- PURPOSE: To explore the motivational orientation for doing research and its relation with attitudes towards science and publication practice among members of faculty at a medical school. ----- METHODS: We used a Science Attitude Survey and the Work Preference Inventory (intrinsic and extrinsic motivational orientation using 4 Likert-type scales of motivation, possible range 1-5) to survey two groups of teachers at the Zagreb University School of Medicine (n = 327, 66% response rate): professors, elected to tenure-track positions (n = 150), and instructor/research fellows working on or just completing their thesis (n = 177). RESULTS: Overall, teachers scored highest on the Enjoyment subscale of intrinsic motivational orientation (mean score +/- standard deviation 4.3 +/- 0.42 for professors vs 4.1 +/- 0.42 for instructors/research fellows, P = 0.001, t-test). Professors also scored higher than instructors/research fellows on the Challenge subscale of intrinsic motivational orientation (3.8 +/- 0.55 vs. 3.5 +/- 0.64, P < 0.001, t-test), whereas instructors/research fellows scored higher on the Compensation subscale of extrinsic motivational orientation (3.5 +/- 0.74 vs. 3.1 +/- 0.71, P < 0.001, t-test). Multiple linear regression analysis showed that the number of publications was positively associated with scores on the Science Attitude Survey and the Challenge subscale of intrinsic motivation, and negatively associated with scores on the Compensation subscale of extrinsic motivation. ----- CONCLUSIONS: Members of the medical faculty differ in motivational orientation for research depending on their academic status, and their motivation is associated more with requirements for academic advancement than with research. These findings have important implications for developing strategies for enhancing academic research production

Systematic tuning of segmented magnetic nanowires into three-dimensional arrays of ‘bits’

A method is presented for the preparation of a three-dimensional magnetic data storage material system. The major ingredients are an inert nanoporous matrix prepared by anodization and galvanic plating of magnetic and non-magnetic metals in wire shape inside the cylindrical pores. The individual nanomagnets consist of a nickel–cobalt alloy, the composition of which is tuned systematically by adjusting the electrolytic bath composition at one optimal applied potential. The lowest magnetocrystalline anisotropy is obtained at the composition Ni60Co40, as quantified by superconducting quantum interference device magnetometry. Wires of this composition experience a pinning-free propagation of magnetic domain walls, as determined by single-wire magneto-optical Kerr effect magnetometry. Adding copper into the electrolyte allows one to generate segments of Ni60Co40 separated by non-magnetic copper. The segment structure is apparent in individual nanowires imaged by scanning electron microscopy, UV-photoelectron emission microscopy, and transmission electron microscopy. The single-domain structure of the wire segments is evidenced by magnetic force microscopy.The research leading to these results has received funding from the European Community's Seventh Framework Program under Grant No. 309589 (M3d). KRS and AN acknowledge funding from Europ¨aischer Fonds fur regionale Entwicklung ¨ (EFRE). Andreas Neff was supported by a scholarship of the Beilstein Institute. ES and MM gratefully acknowledge the nancial support by the German Research Foundation (DFG) through the Cluster of Excellence EXC315 “Engineering of Advanced Materials” and the Research training group GRK1896 “In situ microscopy with electrons, X-rays and scanning probes”