Application of incremental polymeric scales for high precision piezoelectric angular positioning system

A high precision piezoelectric rotational stage with low-cost incremental polymeric scales is proposed and investigated in this work. For avoiding datum plane surface errors caused by application of additional bearings to support the rotational part, the latter one contacts with a stationary piezoelectric disc, which oscillates in travelling wave mode, at three specific points via contacting ring. The resolution of rotation is determined only by geometrical errors of external surface of the piezoelectric disc and can be easily achieved to be in the range of 1 µm. Low-cost polymeric scales are applied to measure angular displacement by means of moiré fringes. Peculiarities of scales fabrication are defined taking into consideration the final accuracy of the device

Assessing the Perceived Effectiveness of the Basic Communication Course: An Examination of the Mass-Lecture Format Versus the Self-Contained Format

This article evaluates the most effective and efficient instructional format for basic communication courses. The results of the analysis lend support to the use of the mass-lecture/laboratory format. Although B. Erikson and D. Strommer indicated that feelings of anonymity, common in the large lecture class, diminished motivation, commitment and personal responsibility of the students, this study did not find similar results. Students indicated, across both instructional formats, comparable perceptions of student motivation, teacher nonverbal immediacy and teacher credibility. It appears that the mass-lecture/laboratory format was perceived by students as being as effective as self-contained sections of basic courses

Self-efficacy Among Students of Pedagogical Universities

This article deals with the questions of self-efficacy among students of pedagogical universities. Results have shown that students-athletes had higher level of physical self-efficacy than students non-athlete

Light-induced reflectivity transients in black-Si nanoneedles

© 2015 Elsevier B.V. All rights reserved. The change in reflectivity of black-Si (b-Si) upon optical excitation was measured by the pump-probe technique using picosecond laser pulses at 532 (pump) and 1064 nm (probe) wavelengths. The specular reflection from the random pattern of plasma-etched b-Si nano-needles was dominated by the photo-excited free-carrier contribution to the reflectivity. The kinetics of the reflectivity were found to be consistent with surface structural and chemical analysis, performed by scanning and transmission electron microscopy, and spectroscopic ellipsometry. The surface recombination velocity on the b-Si needles was estimated to be ~102cm/s. Metalization of b-Si led to much faster recombination and alteration of reflectivity. The reflectivity spectra of random b-Si surfaces with different needle lengths was modeled by a multi-step refractive index profile in the Drude formalism. The dip in the reflectivity spectra and the sign reversal in the differential reflectivity signal at certain b-Si needle sizes is explained by the model

Polypyrrole-Fe2O3 nanohybrid materials for electrochemical storage

We report on the synthesis and electrochemical characterization of nanohybrid polypyrrole (PPy) (PPy/Fe2O3) materials for electrochemical storage applications. We have shown that the incorporation of nanoparticles inside the PPy notably increases the charge storage capability in comparison to the “pure” conducting polymer. Incorporation of large anions, i.e., paratoluenesulfonate, allows a further improvement in the capacity. These charge storage modifications have been attributed to the morphology of the composite in which the particle sizes and the specific surface area are modified with the incorporation of nanoparticles. High capacity and stability have been obtained in PC/NEt4BF4 (at 20 mV/s), i.e., 47 mAh/g, with only a 3% charge loss after one thousand cyles. The kinetics of charge–discharge is also improved by the hybrid nanocomposite morphology modifications, which increase the rate of insertion–expulsion of counter anions in the bulk of the film. A room temperature ionic liquid such as imidazolium trifluoromethanesulfonimide seems to be a promising electrolyte because it further increases the capacity up to 53 mAh/g with a high stability during charge–discharge processes

Alcohol Mixed with Energy Drinks: Consumption Patterns and Motivations for Use in U.S. College Students

Binge drinking in college students is widespread and known to cause significant harms and health hazards for the drinker. One factor that may be exacerbating hazardous drinking in young people is the new popular trend of consuming alcohol mixed with energy drinks (AmED). However, rates of AmED use and motivations for AmED consumption in college students have not been well established. In this study, 706 undergraduate college students from a university in the United States participated in a web-based survey that queried self-reported alcohol, energy drink, and AmED use. In addition, motivations for using AmEDs were assessed. The results indicated that for all participants, 81% reported that they have tried at least one energy drink in the past and 36% reported consumption of at least one energy drink in the past 2 weeks. Alcohol consumption patterns were similar to findings from U.S. national surveys of college drinking, as 37% of respondents were classified as binge drinkers and 23% abstained from drinking. In the whole sample (including the alcohol abstainers), 44% reported trying AmED at least once and 9% reported AmED consumption at least once in the past 2 weeks. 78% of respondents agreed with the statement that AmEDs appeal to underage drinkers. When AmED users were asked about various motivations for consuming AmEDs, users reported that they consumed these beverages to get drunk and reduce sedation compared to alcohol alone. In conclusion, the consumption of AmEDs is common in U.S. college students. Motivations for using AmEDs include the reduction of the sedative effects of alcohol, an important interoceptive cue that one should stop drinking

Hedgehog-Interacting Protein is a multimodal antagonist of Hedgehog signalling

Hedgehog (HH) morphogen signalling, crucial for cell growth and tissue patterning in animals, is initiated by the binding of dually lipidated HH ligands to cell surface receptors. Hedgehog-Interacting Protein (HHIP), the only reported secreted inhibitor of Sonic Hedgehog (SHH) signalling, binds directly to SHH with high nanomolar affinity, sequestering SHH. Here, we report the structure of the HHIP N-terminal domain (HHIP-N) in complex with a glycosaminoglycan (GAG). HHIP-N displays a unique bipartite fold with a GAG-binding domain alongside a Cysteine Rich Domain (CRD). We show that HHIP-N is required to convey full HHIP inhibitory function, likely by interacting with the cholesterol moiety covalently linked to HH ligands, thereby preventing this SHH-attached cholesterol from binding to the HH receptor Patched (PTCH1). We also present the structure of the HHIP C-terminal domain in complex with the GAG heparin. Heparin can bind to both HHIP-N and HHIP-C, thereby inducing clustering at the cell surface and generating a high-avidity platform for SHH sequestration and inhibition. Our data suggest a multimodal mechanism, in which HHIP can bind two specific sites on the SHH morphogen, alongside multiple GAG interactions, to inhibit SHH signalling

Self Assembled Hole Transporting Monolayer for Highly Efficient Perovskite Solar Cells

The unprecedented emergence of perovskite based solar cells PSCs has been accompanied by an intensive search of suitable materials for charge selective contacts. For the first time a hole transporting self assembled monolayer SAM as the dopant free hole selective contact in p i n PSCs is used and a power conversion efficiency of up to 17.8 with average fill factor close to 80 and undetectable parasitic absorption is demonstrated. SAM formation is achieved by simply immersing the substrate into a solution of a novel mole cule V1036 that binds to the indium tin oxide surface due to its phosphonic anchoring group. The SAM and its modifications are further characterized by Fourier transform infrared and vibrational sum frequency generation spectroscopy. In addition, photoelectron spectroscopy in air is used for measuring the ionization potential of the studied SAMs. This novel approach is also suitable for achieving a conformal coverage of large area and or tex tured substrates with minimal material consumption and can potentially be extended to serve as a model system for substrate based perovskite nucleation and passivation control. Further gains in efficiency can be expected upon SAM optimization by means of molecular and compositional engineerin