Evaluation Polyurethane Elastomeric Compound Cps-796-65, Type II

Performance evaluation tests on encapsulating polyurethane elastomeric compound, type II

On the definition and practical use of crystal-based azimuthal angles

A diffractometer‐independent definition of the azimuthal angle ψ of a Bragg reflection is proposed. After completion of intensity measurement, instrument‐dependent and partly redundant quantities such as orientation matrix and setting angles may be replaced by ψ, values without loss of information. Data‐treatment software, such as absorption‐ and anisotropic extinction‐correction programs, become instrument independent and completely general. Formulae are given to compute ψ for equatorial and non‐equatorial diffraction geometries

Curriculum challenges faced by rural-origin health science students at South African medical schools

Background. The current shortage of healthcare workers in rural communities demands attention. The sourcing of rural-origin students (ROSs) has been suggested, but retention of these students in their  chosen degrees is crucial. Addressing the tertiary education challenges that ROSs face is critical to ensuring their success.Objective. To focus on the various challenges influencing throughput of ROSs.Method. This article is one of a series of investigations into various aspects of university life and career choices of health science students. Data were collected at three South African universities by the Collaboration for Health Equity through Education and Research (CHEER) collaborators. Ethical permission was sought from each institution. Health science students at the relevant institutions consented to completing a self-administered questionnaire. The data were analysed on SPSS and ÷2 tests were used to describe the statistical significance of the results.Results. Academic course content was the greatest challenge as perceived by students. Differences  between rural and urban students were significant in all aspects of university life studied. Technological challenges were five times more common for ROSs. Differences between first- and final-year students were not as marked, although the personal challenges and academic course content became easier as students progressed through their degree.Conclusion. Although ROSs face similar challenges as students of urban origin, in some instances these are enhanced and magnified. These students are more likely to find various aspects of university life challenging. To improve the success and retention of ROSs, adequate support structures are essential

Engineering robust polar chiral clathrate crystals

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Royal Society of Chemistry 2013.The R-(+)-enantiomeric form of Dianin's compound and the S-(+)-enantiomeric form of its direct thiachroman analogue both obtained chromatographically employing a cellulose tris(3,5-dimethylphenylcarbamate) column, are shown to undergo supramolecular assembly to form a polar clathrate lattice which is stable even in the absence of a consolidating guest component

Evidence of strategic periodicities in collective conflict dynamics

We analyze the timescales of conflict decision-making in a primate society. We present evidence for multiple, periodic timescales associated with social decision-making and behavioral patterns. We demonstrate the existence of periodicities that are not directly coupled to environmental cycles or known ultraridian mechanisms. Among specific biological and socially-defined demographic classes, periodicities span timescales between hours and days, and many are not driven by exogenous or internal regularities. Our results indicate that they are instead driven by strategic responses to social interaction patterns. Analyses also reveal that a class of individuals, playing a critical functional role, policing, have a signature timescale on the order of one hour. We propose a classification of behavioral timescales analogous to those of the nervous system, with high-frequency, or $\alpha$-scale, behavior occurring on hour-long scales, through to multi-hour, or $\beta$-scale, behavior, and, finally $\gamma$ periodicities observed on a timescale of days.Comment: 22 pages, 7 figures, 1 table. Accepted for publication in Journal of the Royal Society Interfac

A redetermination at low temperature of the structure of triethyl­ammonium bromide

The structure of the title compound, C6H16N+·Br−, was determined at low temperature and the cell dimensions were comparable to those reported for room-temperature studies [James, Cameron, Knop, Newman & Falp, (1985). Can. J. Chem. 63, 1750–1758]. Initial analysis of the data led to the assignment of P31 c as the space group rather than P63 mc as reported for the room-temperature structure. Careful examination of the appropriate |F o| values in the low-temperature data showed that the equalities |F( kl)| = |F(h l)| and |F(hkl)| = |F(hk )| did not hold at low temperature, confirming P31c as the appropriate choice of space group. As a consequence of this choice, the N atom sat on a threefold axis and the ethyl arms were not disordered as observed at room temperature. The crystal studied was an inversion twin with a 0.68 (3):0.32 (3) domain ratio

Bis[4-(dimethyl­amino)phen­yl]diazene oxide

The asymmetric unit of the title compound, C16H20N4O, contains six independent approximately planar mol­ecules and is best described as a commensurate modulation of a P21/c parent. Two sets of disordered mol­ecules share almost the same locations (related by an in-plane translation), ensuring that the c-glide plane condition is not attained. C—H⋯O inter­actions provide structural cohesion. The site occupancy factors of the disordered molecules are ca 0.72/0.28 and 0.67/0.33

Diphenyl[2-(phenyl­sulfon­yl)propan-2-yl]-λ5-phosphane­thione

The title compound, C21H21O2PS2, was obtained from the corresponding dilithio methandiide by treatment with iodo­methane. The bond lengths and angles deviate considerably from those in the dimetallated compound. These differences are most pronounced in the PCS backbone. While the title compound features C—P and C—S distances of 1.9082 (17) and 1.8348 (17) Å, respectively, the dianion showed C—Pav distances shortened by 11% [1.710 (4) Å] and C—S distances shortened by 12% [1.614 (3) Å]. Additionally, the P—C—S angle experiences a contraction by methyl­ation of the dianion from 121.4 (2) to 111.96 (9)° in the title compound

Ethyl 2-[3-(3,5-Dinitrobenzo­yl)thio­ureido]benzoate

In the title compound, C17H14N4O7S, the dihedral angle between the two benzene rings is 9.04 (15)°. The centroid–centroid distance of 3.9825 (19) Å between nearly parallel benzene rings of adjacent mol­ecules suggests the existence of π-π stacking. Inter­molecular and intra-mol­ecular N—H⋯O hydrogen bonding is present in the structure. The eth­oxy group is disordered over two sets of sites with an occupancy ratio of 0.580 (15):0.420 (15). The crystal studied was an inversion twin