Inhibition of UV-induced immune suppression and interleukin-10 production by plant oligosaccharides and polysaccharides

Application of Aloe barbadensis poly/oligosaccharides to UV-irradiated skin prevents photosuppression of delayed-type hypersensitivity (DTH) responses in mice. We tested the hypothesis that these carbohydrates belong to a family of biologically active, plant-derived polysaccharides that can regulate responses to injury in animal tissues. C3H mice were exposed to 5 kJ/m2 UVB from unfiltered FS40 sunlamps and treated with between 1 pg and 10 micrograms tamarind xyloglucans or control polysaccharides methylcellulose or dextran in saline. The mice were sensitized 3 days later with Candida albicans. Tamarind xyloglucans and purified Aloe poly/oligosaccharides prevented suppression of DTH responses in vivo and reduced the amount of interleukin (IL)-10 observed in UV-irradiated murine epidermis. Tamarind xyloglucans were immunoprotective at low picogram doses. In contrast, the control polysaccharides methylcellulose and dextran had no effect on immune suppression or cutaneous IL-10 at any dose. Tamarind xyloglucans and Aloe poly/oligosaccharides also prevented suppression of immune responses to alloantigen in mice exposed to 30 kJ/m2 UVB radiation. To assess the effect of the carbohydrates on keratinocytes, murine Pam212 cells were exposed to 300 J/m2 UVB radiation and treated for 1 h with tamarind xyloglucans or Aloe poly/oligosaccharides. Treatment of keratinocytes with immunoprotective carbohydrates reduced IL-10 production by approximately 50% compared with the cells treated with UV radiation alone and completely blocked suppressive activity of the culture supernatants in vivo. The tamarind xyloglucans also blocked UV-activated phosphorylation of SAPK/JNK protein but had no effect on p38 phosphorylation. These results indicate that animals, like plants, may use carbohydrates to regulate responses to environmental stimuli.     

The Interaction of Benzyl Alcohol with Trimethoxyboroxine : Amine Adducts of Triarylboroxines as Model Compounds

The interaction of benzyl alcohol with trimethoxyboroxine has been investigated by hydrogen-1 and carbon-13 NMR and IR spectroscopy. These techniques indicate formation of a weak Lewis acid/base adduct, additionally stabilized by a hydrogen-bonding interaction, which undergoes rapid ligand exchange at room temperature. The system has been modelled by the synthesis and characterization of a series of amine-triarylboroxine adducts. These adducts rapidly undergo ligand dissociation-recombination in solution with ΔG⁺ of ca. 40-50 kJ/mol.     

Mid-infrared pulses generated from the mixing output of an amplified, dual-wavelength Ti:sapphire system

We demonstrate the generation of femtosecond mid-infrared pulses by direct difference-frequency mixing in a AgGaS(2) crystal of two intense pulses from a dual-wavelength oscillator that have been simultaneously amplified in a single regenerative amplifier. A pulse energy of as much as 1.6 muJ was achieved at wavelengths of 9-11 mum.     

Angularly correlated two-electron repulsion operators

The Bohr model for two-electron atoms is modified to include angular correlation effects in an empirical fashion. An extension of the model to two-centers is given. Simple expressions for one- and two-center Coulomb repulsion integrals are derived and compared with semi-empirical approximations.

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Zusammenfassung Die Bohrsche Modellvorstellung für ein Atom mit zwei Elektronen wird so modifiziert, daß die Winkelkorrelation empirisch berücksichtigt wird. Die Erweiterung dieses Modells auf zwei Zentren wird angegeben. Einfache Ausdrücke für Ein- und Zweizentren-Coulombintegrale werden abgeleitet und mit semiempirischen Näherungen verglichen.

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Based on a thesis submitted by RWS to the State University of New York at Albany in partial fulfillment of the requirements for the degree of Ph. D.     

The temporal effect in listeners with mild to moderate cochlear hearing impairment

This study examines the relationship between a temporal masking effect and cochlear hearing impairment. The threshold level of a long-duration broadband masker needed to mask a short-duration tonal signal was measured for signals presented 2 ms (short-delay) or 202 ms (long-delay condition) after masker onset. The difference between these thresholds is the temporal effect. In two previous studies with normal-hearing listeners, estimates of gain of the cochlear active process derived from such data suggested a decrease in gain during the course of the masker. This hypothesis was further examined in the present study by testing listeners with mild to moderate cochlear hearing impairment. Results are consistent with a decrease in gain in the short-delay condition with increasing hearing impairment, and also less change in gain with increasing hearing impairment.     

The BP<N> Cohomology of Elementary Abelian Groups

In this paper we define three elements of a certain generalisedcohomology ring BPm, n* BV_k. Here m, n and k are non-negativeintegers with k+mn+1, there is a fixed prime p not exhibitedin the notation, and V_k is an elementary Abelian p-group ofrank k. We show that these elements are equal; this is striking,because the three definitions are very different. The significanceof our equation is not yet entirely clear, but it makes contactwith other work in the literature in a number of fascinatingways.     

Entropically Driven Self‐Assembly of Lysinibacillus sphaericus S‐Layer Proteins Analyzed Under Various Environmental Conditions

S‐Layer proteins are an example of bionanostructures that can be exploited in nanofabrication. In addition to their ordered structure, the ability to self‐assembly is a key feature that makes them a promising technological tool. Here, in vitro self‐assembly kinetics of SpbA was investigated, and found that it occurs at a rate that is dependent on temperature, its concentration, and the concentration of calcium ions and sodium chloride. The activation enthalpy (120.81 kJ · mol^?1) and entropy (129.34 J · mol^?1 · K^?1) obtained infers that the incorporation of monomers incurs in a net loss of hydrophobic surface. By understanding how the protein monomers drive the self‐assembly at different conditions, the rational optimization of this process was feasible.

     

Modeling of a two-color, two-stage, ultrafast Yb-doped fiber amplifier

We have modeled a two-stage, Yb-doped fiber amplifier system to amplify two-color ultrafast laser pulses in near-infrared. The first and second stages namely preamplifier and power amplifier are single-clad, single-mode and double-clad, single-mode Yb-doped fibers respectively. From numerical simulations of the modeled fiber amplifiers, the optimal lengths of the two fibers to have equal power at two colors centered at 1035 nm and 1105 nm are in agreement with our experimental results. Numerical simulations have also been performed to demonstrate the impact of using a flat-top, two-color seed spectrum on the system performance.