Cross-field gas breakdown in a coaxial cylinder geometry

Sparking potentials in a coaxial cylinder geometry in oxygen and dry air were measured in crossed electric and magnetic fields. From the data effective collision frequencies were calculated using the equivalent pressure concept. It is shown that the equivalent pressure concept holds good for deriving the effective collision frequencies in non-uniform electric fields.

Attitudes towards suicide among Master’s degree students: a cross-cultural comparison between China and Finland

Attitudes towards suicide among Master’s degree students in Chang Sha (China) and Helsinki (Finland) were compared in order to explore possible cross-cultural differences. The sample included 206 Master’s degree students, 101 Chinese and 105 Finnish. Data were collected using the 30-item Multi-Attitudes Suicide Tendency Scale (MAST) and a demographic information form. According to the results, both Chinese and Finnish students held positive attitudes towards life, they held contradictory attitudes towards suicide, with Finnish students having more permissive and liberal attitudes towards suicide than their Chinese counterparts. In addition, three socio-demographic characteristics, namely religion, family structure, and economic status, associated with attitudes towards suicide among the Chinese Master’s degree students; meanwhile, all socio-demographic characteristics, including gender, religion, major subject, family structure, economic status, and received social support related to attitudes towards suicide among the Finnish Master’s degree students. However, after examining the interaction effect between socio-demographics and cultural backgrounds on attitudes towards suicide, the attitudes of Chinese students were more related to gender, marital status, family economic status, and received social support, whereas Finnish students were more influenced by religion. These findings suggest that culture plays an important role in shaping country-specific differences in attitudes towards suicide and their association with socio-demographic characteristics. Understanding individual attitudes towards suicide could help in intervention to prevent the development of suicidal ideation and in providing appropriate psychological counseling to reduce mental problems. Therefore, these cross-cultural differences may provide indications on how to conduct suicide prevention programs while considering culture-specific contexts.

Allergenic Cross-Reactivity between Parthenium and Ragweed Pollen Allergens

Cross-reactivity of allergens from the pollen of the Compositae weeds, Parthenium hysterophorus (American feverfew) and Ambrosia (ragweed), in 2 groups of patients with different geographic distributions was studied. Parthenium-sensitive Indian patients, who were never exposed to ragweed, elicited positive skin reactions with ragweed pollen extracts. A significant correlation in the RAST scores of Parthenium and ragweed-specific IgE was observed with the sera of Parthenium and ragweed-sensitive Indian and US patients, respectively. RAST inhibition experiments demonstrated that the binding of IgE antibodies in the sera of ragweed-sensitive patients to short (Wl) and giant (W3) ragweed allergen discs could be inhibited by up to 94% by Parthenium pollen extracts. Similar inhibition (up to 82%) was obtained when the sera of Parthenium rhinitis patients were incubated with ragweed allergen extracts. A dose-dependent proliferation of lymphocytes from a Parthenium-sensitive rhinitis patient with elevated levels of both Parthenium and ragweed-specific IgE was observed when incubated with Parthenium and ragweed pollen extracts. A 1.6-fold higher proliferation, however, was observed with Parthenium pollen extract at a concentration of 100 µg/ml. These results suggest that shared epitopes present on Parthenium and ragweed pollen allergens are recognized by both Indian and US patients sensitized by exposure to Parthenium and ragweed pollen, respectively. The high degree of cross-reactivity between Parthenium and ragweed pollen allergens suggests that individuals sensitized to Parthenium may develop type-I hypersensitivity reactions to ragweed and vice versa when they travel to regions infested with the weed to which they had not been previously exposed.

Architecture of Physalis Mottle Tymovirus as Probed by Monoclonal Antibodies and Cross-Linking Studies

Physalis mottle tymovirus (previously named belladonna mottle virus, Iowa strain) RNA was cross-linked to its coat protein by exposure of the intact virus to ultraviolet light. The site of cross-linking of the coat protein with the RNA was identified as Lys-10 by sequencing the oligonucleotide-linked tryptic peptide obtained upon HPLC separation subsequent to enzymetic digestion of the cross-linked and dissociated virus. Three monoclonal antibodies PA3B2, PB5G9, and PF12C9, obtained using denatured coat protein as antigen, cross-reacted effectively with the intact virus indicating that the epitopes recognized by these monoclonals are on the surface of the virus. Using the peptides generated by digestion with CNBr, clostripain, V-8 protease, or trypsin and a recombinant protein lacking the N-terminal 21 residues expressed from a cDNA clone, it was shown that PA3B2 recognizes the sequence 22-36 on the coat protein while PB5G9 and PF12C9 recognize region 75-110. These results suggest that Lys-10 is one of the specific sites through which the RNA interacts in the intact virus. The polypeptide segment (region 22-36) following this buried portion as well as the epitope within the region 75-110 are exposed in the intact virus. These observations are consistent with the canonical β-barrel structure observed in certain other plant viruses.

Influence of Raman scattering on the cross phase modulation in optical fibers

The effect of Raman scattering on co-propagation of two short optical pulses is considered. The intra pulse Raman scattering causes the self-frequency shift of each pulse. The effect of the inter pulse Raman scattering is to enhance the frequency shift while the stimulated Raman scattering (SRS) term suppresses (enhances) the frequency shift if the center frequency difference between the optical pulses falls to the right (left) of the Raman gain peak. An expression for the frequency shift as a function of the propagation distance is obtained.

Conformational analysis and design of cross-strand disulfides in antiparallel beta-sheets

Cross-strand disulfides bridge two cysteines in a registered pair of antiparallel beta-strands. A nonredundant data set comprising 5025 polypeptides containing 2311 disulfides was used to study cross-strand disulfides. Seventy-six cross-strand disulfides were found of which 75 and 1 occurred at non-hydrogen-bonded (NHB) and hydrogen-bonded (HB) registered pairs, respectively. Conformational analysis and modeling studies demonstrated that disulfide formation at HB pairs necessarily requires an extremely rare and positive chi(1) value for at least one of the cysteine residues. Disulfides at HB positions also have more unfavorable steric repulsion with the main chain. Thirteen pairs of disulfides were introduced in NHB and HB pairs in four model proteins: leucine binding protein (LBP), leucine, isoleucine, valine binding protein (LIVBP), maltose binding protein (MBP), and Top7. All mutants LIVBP T247C V331C showed disulfide formation either on purification, or on treatment with oxidants. Protein stability in both oxidized and reduced states of all mutants was measured. Relative to wild type, LBP and MBP mutants were destabilized with respect to chemical denaturation, although the sole exposed NHB LBP mutant showed an increase of 3.1 degrees C in T-m. All Top7 mutants were characterized for stability through guanidinium thiocyanate chemical denaturation. Both exposed and two of the three buried NHB mutants were appreciably stabilized. All four HB Top7 mutants were destabilized (Delta Delta G(0) = -3.3 to -6.7 kcal/mol). The data demonstrate that introduction of cross-strand disulfides at exposed NHB pairs is a robust method of improving protein stability. All four exposed Top7 disulfide mutants showed mild redox activity. Proteins 2011; 79: 244-260. (C) 2010 Wiley-Liss, Inc.

Pulsatile flow of a viscous fluid in elliptical pipe of variable cross-section

The pulsatile flow of an incompressible viscous fluid in an elliptical pipe of slowly varying cross-section is considered. Asymptotic series solutions for the velocity distribution and pressure gradient are obtained in terms of Mathieu functions for a low Reynold number flow in which the volume flux is prescribed. An expression for shear stress on the boundary is derived. The physically significant quantities governing the flow are computed numerically and analysed for different types of constrictions. The effect of eccentricity and Womerslay parameter on the flow is discussed.

Formation of a single, rotated-Brass (1 1 0)< 5 5 6 > texture by hot cross-rolling of an Al-Zn-Mg-Cu-Zr alloy

The present work describes the evolution of a strong, single-component rotated-Brass ((1 1 0) < 5 5 6 >) texture in an Al-Zn-Mg-Cu-Zr alloy by an uneven hot cross-rolling with frequent interpass annealing. This texture development is unique because hot rolling of aluminum alloys results in orientation distribution along the ``beta-fibre''. It has been demonstrated that the deformation by cross-rolling of a partially recrystallized grain structure having rotated-Cube and Goss orientations, and the recrystallization resistance of near-Brass-oriented elongated grains play a critical role in development of this texture. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Free convection about cylinders of elliptic cross section embedded in a porous medium

Numerical solutions are presented for the free convection boundary layers over cylinders of elliptic cross section embedded in a fluid-saturated porous medium. The transformed conservation equations of the nonsimilar boundary layers are solved numerically by an efficient finite-difference method. The theory was applied to a number of cylinders and the results compared very well with published analytical solutions. The results are of use in the design of underground electrical cables, power plant steam, and water distribution lines, among others.