Proton-nucleus inelastic cross section at ultra high energy

Energy dependence of proton-nucleus reaction cross section at very high energy is discussed. It is stressed that depending on the gluon distribution near the nuclear surface, proton-nucleous total cross section increases much more rapidly compared to the usual Glauber independent nucleon estimate. The recent observation of smaller X _max than the expected value at UHECR domain can be an indication for such a mechanism.     

Polymeric Derivatives of Chloramphenicol and Their Antibacterial Properties

The polymerizable derivatives of chloramphenicol were prepared and free-radical copolymerized with acrylamide, methacrylic acid, and 2-(dimethylamino)ethyl methacrylate in order to obtain polymers with pharmacological activity. The monomeric and polymeric derivatives were subjected to antibacterial activity tests against Bacillus polymyxa.     

Bis(2‐methyl­imidazolium) hydroxodiphosphatoaluminium

The title compound, (C₄H₇N₂)₂[AlP₂O₇(OH)], is a one‐dimensional extended‐chain aluminophosphate prepared by a solvothermal synthesis from an alcohol system. The infinite [AlP₂O₇(OH)]²⁻ chains composed of AlO₄, PO₂(=O)₂ and PO₂(=O)(OH) tetrahedra are linked via hydrogen bonds to the 2‐methyl­imidazolium cations.     

Thermal stability of alignment of a nematic liquid crystal induced by polyimides exposed to linearly polarized light

The thermal stability of alignment of a nematic liquid crystal (LC) on three polyimide (PI) films exposed to linearly polarized light at 366 nm was investigated. Polarizing optical microscopy analysis indicates that the thermal stability of the LC alignment on the PI film without significant structural change was higher than that with obvious structural change.     

Micro determination of cortisol and cortisone in umbilical cord blood by chemiluminescent high‐performance liquid chromatography

A simple, sensitive and specific chemiluminescent high‐performance liquid chromatography method, based on the luminol reaction, for determination of serum cortisol and cortisone, was established. In infants, placental 11β‐hydroxysteroid dehydrogenase type 2 enzyme (11β‐HSD2) activity may affect adrenal function early after birth. The cortisol–cortisone ratio of serum concentrations in umbilical cord blood is an indicator of placental 11β‐HSD2 activity. The optimum conditions for the luminol reaction were determined to be 1.5 mM luminol, 0.6 M sodium hydroxide, 0.15 mm potassium hexacyanoferrate(III) and 200 mM potassium hexacyanoferrate (II). The calibration curves for cortisol and cortisone exhibited good linearity. The correlation coefficients of the calibration curves were 0.996. The intra‐ and inter‐day precisions were in the ranges: cortisol 7.0–12.2 and 4.4–9.2%, cortisone 5.3–7.0 and 6.2–9.9%. The recoveries of these steroids were in the ranges: cortisol 97–105%, cortisone 94–102%. The limits of detection were as follows: cortisol, 0.17 μg/dl; cortisone 0.15 μg/dl. This assay could be successfully applied to determination of the cortisol–cortiosone ratio of serum concentrations in umbilical cord bloods. Copyright © 2009 John Wiley & Sons, Ltd.     

Acceleration effect of N‐allyl group on thermally induced ring‐opening polymerization of 1,3‐benzoxazine

Thermally induced ring‐opening polymerization of monofunctional N‐allyl‐1,3‐benzoxazine 1a was compared with that of N‐(n‐propyl)‐1,3‐benzoxazine 1b to clarify an unexpected effect of allyl group to promote the polymerization, that is, in spite of the comparable bulkiness of allyl group to n‐propyl group, the polymerization of 1a was much faster than that of 1b . Such a difference in polymerization rate was also observed similarly in the comparison of thermally induced polymerization of a bifunctional N‐allyl‐benzoxazine 2a with that of a bifunctional N‐(n‐propyl) analogue 2b . These observations implied a certain contribution of an electron‐rich C? C double bond of the N‐ally group to promotion of the ring‐opening reaction of 1,3‐benzoxazine into the corresponding zwitterionic species, which would involve a mechanism to stabilize the cationic part of the zwitterionic species based on “neighboring group participation” of the C? C double bond. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010