Analytical method of clofencet in animal fishery products by LC/MS

A method for the determination of clofencet in animal and fishery products was developed, using liquid chromatography with electrospray ionization mass spectrometry (LC/ESI-MS). The sample was homogenized with water and hexane, and the homogenate was extracted with acetonitrile, then acetonitrile-water (4 : 1). An aliquot of the crude extract was passed through a C18 cartridge column (1,000 mg), and the eluate was concentrated. A solution of 10% sodium chloride and 1% sodium hydrogen carbonate, and ethyl acetate were added to the residue, and the mixture was shaken. After shaking, the aqueous phase was recovered and acidified with hydrochloric acid, and then clofencet was extracted with ethyl acetate. The extract was evaporated to dryness and the residue was dissolved in methanol-water (3 : 7). Clofencet was analyzed by LC/MS. The recoveries of clofencet from ten kinds of animal and fishery products were 77.8-97.8%, and the relative standard deviations were 0.6-5.8% (n=5). S/N of the peak of clofencet was >10 and no interfering peak was found in animal and fishery products fortified at 0.01 mg/kg.     

Regulation of CTL by ecto-nictinamide adenine dinucleotide (NAD) involves ADP-ribosylation of a p56lck-associated protein

Receptor-mediated activation of T lymphocytes involves protein phosphorylation by several protein tyrosine kinases, among those the src-related enzymes p56lck and p59fyn. Accumulating evidence supports the notion that these enzymes are regulated by tyrosine phosphorylation and dephosphorylation, but much is yet to be learned about regulation of their activity. Here we demonstrate that p56lck but not p59fyn exists as a complex with a 40-kDa protein, which in its ADP-ribosylated form inhibits p56lck kinase activity. ADP-ribosylation of this protein is mediated by an arginine-specific mono-ADP-ribosyltransferase, which makes use of extracellular nicotinamide adenine dinucleotide (NAD). This enzyme is a glycosyl-phosphatidylinositol-anchored protein releasable from the surface of cytotoxic T cells by glycosyl-phosphatidylinositol-specific phospholipase C. Release of arginine-specific mono-ADP-ribosyltransferase results in failure of extracellular NAD to downmodulate p56lck kinase activity. Concomitant to suppression of the kinase by NAD, CD8 mediated transmembrane signaling and p56lck kinase activation are inhibited.     

Grinding Forces and Elastic Recovery in Ceramic Materials

Understanding grinding technology using a diamond grinding wheel is very important to achieve the dimensional accuracy of the final product in structural application of ceramics. Because Si₃N₄ is very difficult to grind, its grindability, which is estimated from the grinding force, is examined with regard to some of its physical properties. The difficult-to-grind nature of Si₃N₄ depends on its high elastic recovery energy.     

An integrated switched-capacitor signal processing design system

A CAD system integrating switched-capacitor network function synthesis, circuit synthesis, and layout is presented. The tool addresses the design of programmable gain, cosine, interpolation, and arbitrary transfer functions in addition to canonical filter structures. Amplifier design is based on numerical optimization of highly accurate analytic models derived with the aid of symbolic-mathematics-based model development aids. The physical design of the filter is created by a general-purpose switched-capacitor circuit synthesizer. The tool makes it possible to synthesize a complete switched-capacitor signal path with full handcrafted quality in a single day. Examples taken from actual IC designs illustrate the utility and accuracy of the various functions     

Ferrimagnetic Particles in the Lung Part 1: The Magnetizing Process

The magnetization process of ferrimagnetic particles in the lung takes place when an external magnetic field is applied to the lung; the particles both become magnetized and rotate toward alignment with the applied field. The purpose here is to consolidate previous and new measurements of this process, for Fe3O4 particles in the human lung, and to interpret the measurements. The particular quantity measured was Bn, the remanent magnetic field at the chest produced by the particles after removal of the applied field. Bn was measured as a function of three variables. The first two are the strength and duration of the applied field, yielding the remanent magnetization curve and the viscosity curve respectively; these were measured both for particles initially unmagnetized and initialiy magnetized. The curves are qualitatively explained by a simple physics model consisting of single-domain and multidomain particles; these reside in a viscous fluid and experience physiological impulses (relaxation) which oppose the alignment during magnetization. The third variable is the state of breathing; Bn was measured when normal breathing was switched to exhale-and-hold during either magnetization or measurement. The effects on Bn of this switch are explained by considering the alveolar walls; forced exhalation is assumed to "crumple" the walls, thereby realigning the particles contained in the alveoli.     

An investigation of strain hardening and creep in an AI-6061/AI2O3 metal matrix composite

Experiments were conducted to compare the influence of temperature on the flow and strain-hardening characteristics of an Al-6061 metal matrix composite, reinforced with ∼20 vol pct of Al₂O₃-based microspheres, with the unreinforced monolithic alloy. At room temperature, the yield stresses and the strain-hardening rates are higher in the composite material in the asquenched condition and after aging at 448 K for periods of time up to 300 hours. The 0.2 pct proof stress and the strain-hardening rate decrease with increasing temperature in both materials, but the rate of decrease is faster in the composite so that the unreinforced monolithic alloy exhibits higher yield stresses and strain-hardening rates at temperatures in the vicinity of 600 K. Under conditions of constant stress at high temperatures, the composite exhibits both a higher creep strength than the monolithic alloy and higher values for the stress exponents for creep. Formerly Visiting Scholar, Kyushu University, is Associate Professor, Department of Metallurgy, Xian Institute of Metallurgy and Construction Engineering, Xian 710055, People’s Republic of China.     

Blockage of mesenteric lymphatic flow in rats

An experimental model of blockage of the mesenteric lymphatic flow (MLF) in rats was designed, and morphologic changes of mesenteric lymphatic vessels (MLV) and lymph nodes were investigated by mesenteric lymphangiography and histopathologic examination. Body weight in rats with blockage of MLF did not increase normally. Mesenteric lymphangiography revealed dilation of the MLV, reverse flow into the peripheral MLV, and leakage of contrast medium, resulting in chylous ascites. Remarkable dilation of the lymphatic sinuses and dilated and increased rough endoplasmic reticulum in lymphocytes in the mesenteric lymph nodes due to lymph stagnation were observed by light and electron microscopic examination, respectively.     

Fosfomycin reduces CD15s-related antigen expression of Streptococcus pyogenes

We have transfected a full-lenght cDNA-encoding human tissue inhibitor of metalloproteinases-1 (TIMP-1) by lipofection in highly invasive F3II mouse mammary sarcomatoid carcinoma cells. In vitro, overexpression of TIMP-1 was associated with abrogation of metalloproteinase activity, extended doubling time, and a more flattened, epithelioid polyhedric morphology. Female Balb/c mice inoculated subcutaneously with TIMP-1 transfectant exhibited a prolonged tumor latency and tumor burden was significantly lower in early stages of tumor growth. Control F3II cells grew by invading the muscular and adipose layers of the subcutis, dermis, and dermal papillae. On the contrary, mammary carcinoma cells transfected with TIMP-1 grew without signs of active invasion of dermis. Tumors also revealed a decreased amount of necrosis and host inflammatory cell infiltrates. However, histological analysis did not demonstrate any change in vascular density. Animals bearing F3II tumors overexpressing TIMP-1 showed a significant reduction in the size of metastatic lung nodules. These data suggested that TIMP-1 overexpression may reduce local invasion and delay the progression of the metastatic disease in the present mammary tumor model.     

Brasilinolide A, a new macrolide antibiotic produced by Nocardia brasiliensis: producing strain, isolation and biological activity

A new 32-membered macrolide antibiotic, brasilinolide A was isolated from the fermentation broth of Nocardia sp. IFM 0406. The producer was identified as Nocardia brasiliensis. The antibiotic was only active against Aspergillus niger, but not active against other fungi including yeasts as well as other filamentous like fungi and bacteria. Brasilinolide A exerted an immunosuppressive activity in the assay system of a mixed lymphocyte reaction (MLR).