Effect of Laser Phototherapy on Enzymatic Activity of Salivary Glands of Hamsters Treated with 5‐Fluorouracil

The chemotherapeutic agent 5‐Fluorouracil (5‐FU) can induce salivary gland hypofunction (SGH); however, previous studies did not reach final conclusions on the influence of this drug on glandular tissue. Thus, the aim of this study was to investigate the effect of 5‐FU on submandibular (SMs) and sublingual glands (SLs), as well as, the effect of laser phototherapy (LPT) on SGH induced by 5‐FU. Eighty‐five hamsters were divided into three groups: control (C), chemotherapy (CT) and laser (L), and the SGH was induced by two injections of 5‐FU in groups CT and L. The irradiation was performed using a diode (λ780 nm/20 mW/5 J cm^?2/0.2 J and 10 s per point/spot size of 0.04 cm²) and applied daily. On the euthanasia day, SMs and SLs were removed and biochemical analyses were carried out. The lactate dehydrogenase activity was increased in group CT when compared with group C for SLs and SMs (P < 0.05). In addition, the peroxidase and catalase activities were increased and superoxide dismutase was decreased by 5‐FU (P < 0.05). However, LPT appears to be a protective mechanism against oxidative stress, tending to alter the activity of these antioxidant enzymes, suggesting LPT as a promising therapy to modulate the 5‐FU harmful effect.     

Screening and Xylanase Production by Streptomyces sp. Grown on Lignocellulosic Wastes

Xylanases have raised interest because of their potential applications in various industrial fields, including the pulp and paper industries, bioethanol production, and the feed industry. In bioethanol production from lignocellulosic compounds, xylanase can improve the hydrolysis of cellulose into fermentable sugars, since the xylan restricts the cellulases from acting efficiently. In this work, a new thermophilic Streptomyces sp. was selected for its ability to produce xylanase. Carbon source selection is an important factor in the production of hemicellulases. The highest activity was obtained when Streptomyces sp. I3 was grown in the presence of wheat bran. Xylanase activity was partially characterized concerning the effect of pH and temperature on activity and thermostability, and the effects of different metal ions were also tested. The pH and temperature profile showed optimal activity at pH 6.0/70 °C. Zymogram analysis showed multiple xylanases (39, 21, 18, and 17 kDa). Xylanases studied in this work are thermophilic, thermostable, and active in a wide pH range; they have potential to be used in the development of new processes of biotechnological interest.     

Synthesis of nickel(II) triazolenaphthalocyanine and related macrocycles.

The synthesis of novel monbenzotriazolephthalocyanines (3-6), low-symmetry phthalocyanine analogues, is described for the first time using a novel and simple stepwise strategy which involves the use of substituted naphthalodinitriles 8-11 and appropriately substituted three-unit compounds such as 7. Belonging to the same family, compound 1, which we have called triazolenaphthalocyanine, has been prepared by a statistical method from compound 2 and 3,5-diamino-1,2,4-triazole. Compound 1 shows a bathochromic shift of the Q-band in UV-vis spectrum due to the fusing of benzene rings to the triazolephthalocyanine core.     

Low-temperature heat transport in α-HgI2 single crystals

The thermal conductivity of several samples from α-HgI₂ crystals grown by two different methods has been measured from 50 mK to 200 K. The thermal conductivity is found to be intrinsic but anisotropic above 15 K: it is smaller along c-axis than along a-axis, the anisotropy ratio being about 5 between 15 and 200 K. Below 15 K, the thermal conductivity is sample dependent and the calculated Casimir limit is not reached at the lowest temperatures. The results have been interpreted considering phonon scattering by structural defects. A simple quantitative analysis of the curves suggests that phonons are scattered mainly by large clusters of interstitial defects due to the lack of stoichiometry of the crystals; the typical dimensions of these clusters are not smaller than 1 μm perpendicular to c-axis and 0.3 /gmm along c-axis. The presence of plane defects is also detected. Point defect scattering is relatively small and explained by residual metallic impurities and carbon at interstitial sites. The intrinsic anisotropy is briefly discussed.     

Covalent Immobilization of α-Galactosidase from <Emphasis Type="Italic">Penicillium griseoroseum</Emphasis> and its Application in Oligosaccharides Hydrolysis

Partially purified α-Galactosidase from Penicillium griseoroseum was immobilized onto modified silica using glutaraldehyde linkages. The effective activity of immobilized enzyme was 33%. Free and immobilized α-galactosidase showed optimal activity at 45 °C and pH values of 5 and 4, respectively. Immobilized α-galactosidase was more stable at higher temperatures and pH values. Immobilized α-galactosidase from P. griseoroseum maintained 100% activity after 24 h of incubation at 40 °C, while free enzyme showed only 32% activity under the same incubation conditions. Defatted soybean flour was treated with free and immobilized α-galactosidase in batch reactors. After 8 h of incubation, stachyose was completely hydrolyzed in both treatments. After 8 h of incubation, 39% and 70% of raffinose was hydrolyzed with free and immobilized α-galactosidase respectively. Immobilized α-galactosidase was reutilized eight times without any decrease in its activity.     

The generalized corona theorem

The results of this paper have been presented by the second author at the joint AMS-DMV Meeting 1993 in Heidelberg (Germany)     

Thin-layer chromatographic determination of catecholamines, 5-hydroxytryptamine, and their metabolites in biological samples: a review

A review of methodology for separation, detection, and quantitative determination of catecholamines, 5-hydroxytryptamine, and their acidic metabolites in biological tissue and fluids by thin-layer chromatography is presented. Selected procedures, including fluorometric scanning densitometry for catecholamine acetyl derivatives and color scanning densitometry for acids, are described.     

Oscillation of Functions in the Hölder Class

Potential Analysis - We study the size of the set of points where the α-divided difference of a function in the Hölder class Λα is bounded below by a fixed positive constant....