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薛敏敏 《合成纤维》2007,36(6):48-50
自1992年来,市场上出现一种新型的纤维素纤维Lyocell纤维。它具有改进的性能,并用N-甲基吗琳-N-氧化物(NMMO)作为纤维素的直接溶剂进行生产。Lodz工业大学化学纤维系和天然纤维研究所已开始研究纳米纤维素纤维——新一代Lyocell纤维,生产时也使用NMMO。论述了Lyocell纤维技术范围内研究工作的最新发展,主要是纳米纤维素纤维的研究工作。  相似文献   
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Multifocal fibrosclerosis, as the name implies, concerns disseminated fibrous processes that manifest as Riedel's thyroiditis, idiopathic retroperitoneal fibrosis, mediastinal fibrosis, sclerosing cholangitis, and pseudotumor of the orbit. Certain cases of fibrosis of the parotid gland, the lacrimal glands, and the lung may belong in the same category. The cases of two patients with Riedel's thyroiditis, one of whom also has retroperitoneal fibrosis, are described. Unusual changes in the small and middle-sized veins in the fibrous tissue in the thyroid and in the retroperitoneum, best designated "occlusive phlebitis," seem to be characteristic of the multifocal fibrosclerosis. They may contribute to the disease process.  相似文献   
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Gene expression profiling via quantitative real-time PCR is a robust technique widely used in the life sciences to compare gene expression patterns in, e.g., different tissues, growth conditions, or after specific treatments. In the field of plant science, real-time PCR is the gold standard to study the dynamics of gene expression and is used to validate the results generated with high throughput techniques, e.g., RNA-Seq. An accurate relative quantification of gene expression relies on the identification of appropriate reference genes, that need to be determined for each experimental set-up used and plant tissue studied. Here, we identify suitable reference genes for expression profiling in stems of textile hemp (Cannabis sativa L.), whose tissues (isolated bast fibres and core) are characterized by remarkable differences in cell wall composition. We additionally validate the reference genes by analysing the expression of putative candidates involved in the non-oxidative phase of the pentose phosphate pathway and in the first step of the shikimate pathway. The goal is to describe the possible regulation pattern of some genes involved in the provision of the precursors needed for lignin biosynthesis in the different hemp stem tissues. The results here shown are useful to design future studies focused on gene expression analyses in hemp.  相似文献   
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The influence of anti-IGF-1 and anti-transforming growth factor beta (TGF-beta) neutralizing antibodies on preadipocyte differentiation and secretion of IGFBPs was examined in serum free porcine stromal-vascular cultures. Cultures were stained for morphological analysis and conditioned media were collected for: TGF-beta determination by ELISA, IGF-1 by RIA, and IGFBP analysis by ligand blotting. After 6 d of treatment, anti-TGF-beta increased fat proportions by 2.7 fold compared to controls. Anti-IGF-1 decreased fat cell proportions by 14-fold. Anti-TGF-beta increased concentrations of IGF-1 5.8-fold and IGFBP-2 and IGFBP-3 by 8- and 7-fold in conditioned media whereas IGFBP-4 decreased 5-fold. Anti-IGF-1 increased concentrations of IGFBP-2 and 3 by 9- and 35-fold, respectively. TGF-beta increased concentrations of IGFBP-1, 2 and 3 by 3-fold, 18-fold and 3-fold, respectively, after 9 d in culture (6 d of treatment). There was no change in TGF-beta levels in anti-IGF-1 treated cultures compared to controls. Control antibodies and negative controls had no effect. These results provide evidence that endogenously produced IGF-1 and TGF-beta has a major influence on preadipocyte differentiation in serum free media by modulating IGFBP production/secretion.  相似文献   
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Models are currently available for representing the dynamical behavior of most water network components. Such models are relatively simple, accurate and can be easily solved. However, there is no generally accepted dynamic model of a pressure reducing valve (PRV). The key contributions of this paper are the development of several dynamic models—two phenomenological, one behavioral, and one linear—to represent the behavior of PRVs. The models vary in complexity but perform similarly. Experimental data is used to assess the accuracy of the models. The phenomenological models are derived from physical laws and provide an excellent but complex representation of a PRV. The behavioral model is simpler and sufficient for most practical purposes. The linear model does not take the needle valve setting (which controls the valve’s speed) into account and therefore has limited use.  相似文献   
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1. A method developed for the isolation of phosvitin from chicken egg yolk was successfully applied to the isolation of phosvitin from salmon eggs. 2. Salmon roe phosvitin is smaller in molecular size than chicken egg phosvitin. 3. Circular dichroism spectra of all phosvitins investigated displayed good similarities with spectra showing characteristics of unordered and beta-sheet secondary structure. 4. The main component in the Fourier transform infrared spectra of chicken egg phosvitin is indicative of unordered conformation, whereas the Fourier infrared data of the salmon egg phosvitin are consistent with more of beta-sheet structure compared to the chicken egg phosvitin.  相似文献   
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Apolipoprotein[a] (apo[a]) is a highly polymorphic glycoprotein that forms a covalent complex with apolipoprotein B-100 (apoB-100), producing a lipoprotein species referred to as lipoprotein[a] (Lp[a]). We have studied the effects of alterations in glycosylation of apo[a] on its intracellular processing and secretion as well as its ability to associate with low density lipoprotein (LDL) apoB-100. HepG2 cells transfected with a 6 kringle IV (6 K-IV) apo[a] minigene were treated with tunicamycin, an inhibitor of N-linked glycosylation, which eliminated apo[a]-B-100 complexes from the media. Tunicamycin treatment also reduced secretion of the 6 K-IV apo[a] protein from transfected McA-RH7777 cells by approximately 50%, but completely eliminated secretion of apo[a] species containing 9 and 17 K-IV repeats. Mixing experiments, performed with radiolabeled media (+/-tunicamycin) from transfected McA-RH7777 cells, demonstrated no alteration in the extent of association of apo[a] with human LDL. Similar mixing experiments using culture media from glycosylation-defective mutant chinese hamster ovary (CHO) cells transfected with the same apo[a] minigene showed identical results. Apo[a] secretion was demonstrated in all mutant cell lines in the absence of either N- or O-linked (or both) glycosylation. The mechanisms underlying the reduced secretion of apo[a] from transfected hepatoma cells were examined by pulse-chase radiolabeling and apo[a] immunoprecipitation. Tunicamycin treatment altered the efficiency of precursor apo[a] processing from the ER by increasing its ER retention time. The increased accumulation of precursor apo[a] in the ER was associated with alterations in the kinetics of association with two resident endoplasmic reticulum (ER) chaperone proteins, calnexin and BiP. These findings suggest that the glycosylation state and size of apo[a] appear to play a role in regulating its efficient exit from the endoplasmic reticulum. However, neither N- nor O-linked glycosylation of apo[a] exerts a major regulatory role in its covalent association with apoB-100.  相似文献   
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The founder and first director of the C.C.R. enumerates the principles that led to the conception and the achievement of the C.C.R. He reviews the principal rescue activities during these 25 years and mentions the development of supplementary activities on safety, ergonomics and respiratory protection during the last few years.  相似文献   
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