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Functional assembly of the plasminogen-dependent proteolytic system on the cell surface requires multiple interactions involving urokinase (uPA), urokinase receptor (uPAR), plasminogen activator inhibitors, and other molecules that mediate cell migration and adhesion. We analyzed the in vitro interaction of uPAR-containing particulate cell fractions with the amino-terminal fragment (ATF) of human urokinase and the matrix-like form of vitronectin. Binding and cross-linking of 125I-labeled ATF to crude membrane extracts from LB6-19 mouse cells overexpressing human uPARs in the presence of 25 nM urea-denatured vitronectin led to the formation of Mr 137,000, 92, 000, and 82,000 covalent complexes. Immunoprecipitation of the preformed cross-linked 125I-labeled complexes with anti-vitronectin, anti-uPA, or anti-uPAR antibodies revealed that the Mr 82,000 and 92, 000 species do contain ATF and vitronectin and identified the Mr 137, 000 species as a ternary complex formed by ATF, uPAR, and vitronectin. A similar electrophoretic pattern was displayed by acid-pretreated membranes extracted from MCF-7 breast carcinoma or HT1080 fibrosarcoma cell lines, as well as a ductal breast carcinoma specimen; the latter exhibited complex formation at concentrations of vitronectin lower than 10 nM. Finally, uPAR-vitronectin interaction was further documented by the decreased reactivity of an anti-uPAR polyclonal antibody to acid-pretreated sections of 10 breast carcinomas that had been preincubated with vitronectin. Our findings highlight the ability of uPAR to interact simultaneously with vitronectin and uPA in breast cancer, supporting a dynamic coupling of the molecular mechanisms underlying plasminogen-dependent matrix degradation and cell adhesion.  相似文献   
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Green tea is proved to be a source of various biochemicals, which projects tea to be a health drink. The study investigated free radical scavenging activity of leaf extracts of south Indian tea clones, individual catechin molecules and documented the influence of various additives on the scavenging activity of black tea infusion. Among the tea clones, UPASI-17 contained higher quantum of catechins. Lower content of catechins correlated with low 1,1-diphenyl-2-picrylhydrazyl and hydroxyl scavenging activities. Low scavenging activity was noticed in gallocatechin. A wide variation was found in free radical scavenging activity of individual molecules, leaf extracts, tea liquor and its combination with the additives. Tea liquor along with lemon juice showed the highest free radical scavenging activity. When sugar and lemon juice were amended with tea liquor, free radical scavenging activity declined marginally. Addition of milk and sugar with tea liquor declined the free radical scavenging activity significantly.  相似文献   
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In two experiments, event-related brain potential were recorded to word pairs simultaneously presented to both ears, with instructions to attend to one ear and detect occasional nonwords in that ear. This attentional manipulation yielded four patterns of word repetition on successive trials: first and second presentations attended (AA), both unattended (UU), and across ears (AU and UA). A prominent attenuation of N400 due to immediate repetition of words was observed on AA trials. However, when first presentations were ignored on UU and UA trials, no repetition effect was obtained. These findings indicate that the repetition effect on N400 depends on attentional processing of first presentations.  相似文献   
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Hyuganatsu is a typical Japanese citrus with desirous smell and edible albedo. The objectives of this study are to establish a method for softening hyuganatsu peel without heating and a process for making a high pressure-induced (HP-) marmalade and to compare with heat-induced (H-) marmalade and citrus shaddock family marmalade. Firmness of peel was (greatest to least) pressurized at 500 MPa for 30 min, soaked in citric acid solution at pH 2.7 for 24 h, and boiled for 10 min, respectively. The cell walls of flavedo and albedo did not loosen after pressurization. However, after soaking or heating, the middle lamella of albedo separated. When flavedo was soaked at pH 2.7, 9.3% of pectin was extracted. The amount of naringin was the least in hyuganatsu 〈 pummelo 〈 grapefruit), and juice sacs 〈 flavedo 〈 segment walls 〈 albedo, respectively. Thus, marmalade was processed. Albedo, segment walls and juice sacs of hyuganatsu were homogenized with citric acid solution (pH 2.7) and mixed with sliced flavedo. Then it was soaked for 24 h at pH 2.7. Sucrose was then added (final sugar 50%), vacuum packed, then pressurized for 30 min at 500 MPa or boiled for 10 min, respectively. There was no significant difference in sensory evaluation between HP- and H-marmalade. However, the color, transparency and total evaluation of HP-marmalade were better than H-marmalade. Consequently, total evaluation of hyuganatsu-HP-marmalade was rated highly. So, hyuganatsu was considered to be more suitable for marmalade because it was more palatable than the others.  相似文献   
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The handling and storage of black tea at high humidity increases its moisture content, which encourages microbial growth. γ irradiation is one of the most efficient techniques for the reduction of microorganisms in food. The present study aimed to evaluate the effect of γ irradiation on black tea quality and microbial load, during storage. Irradiation had a significant effect on reducing the microbial load, while untreated samples had a high microbial load. Untreated samples absorbed moisture up to 8.65% in 12 months time, whereas it was 6.0% in the case of irradiated samples. The quality of the irradiated teas exhibited stability in major parameters like theaflavin (TF), thearubigin (TR), highly polymerized substances (HPS), and total liquor colour (TLC). There was no significant difference among the quality characteristics of 7 kGy and 10 kGy irradiated samples during the entire period of storage when compared with 0 day control. Results indicated a deterioration in quality of well packed, but untreated control samples during storage. Irradiation resulted in complete removal of microbes and extended the shelf life of black tea.  相似文献   
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The influence of age after pruning on the biochemical constituents such as catechin fractions, the key enzyme phenylalanine ammonia lyase (PAL) and other compounds which contribute to black tea quality as well as root carbohydrates was investigated. Analyses were done consecutively for 4 years after pruning. The concentration of total catechins was found to be highest in the ‘Cambod’ cultivar UPASI‐17, followed by UPASI‐3 and UPASI‐9 representing ‘Assam’ and ‘China’ jats respectively, under prevailing conditions. A concomitant increase in total catechin content was found up to 3 years followed by a decrease in the fourth year of the pruning cycle, irrespective of the cultivar. PAL, the precursor of catechin biosynthesis, also increased up to 3 years and showed a sharp decrease thereafter. On the other hand, the root carbohydrate reserve and the caffeine content of tea leaves increased steadily up to the fourth year. All the genotypes studied showed the same trend. However, variability in catechin contents was prominent in different clones. Copyright © 2005 Society of Chemical Industry  相似文献   
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The flesh of spaghetti squash separates into strands when cooked. The purpose of this paper is to investigate the cause of strand separation (during cooking) by soaking for 24 h at 35 ℃ in solutions with three kinds of pectin extractant. The changes in strand separation, firmness, histological structure and the pectin of flesh during soaking in 0.01 N HCI solution (pH 2.0), 0.035 M ammonium oxalate solution (pH 4.0) or 2% sodium hexametaphosphate solution (pH 4.0) were investigated. When flesh was soaked in the HCI solution, the separation into strands and removal of calcium and magnesium were greater than that soaked in other pectin extractants. High methoxyl pectin was extracted by soaking in HC1 solution (pH 2.0) due to removal of polyvalent cations. This result shows that high methoxyl pectin glues strands together in the flesh of spaghetti squash. The shape of the cells which constituted strands was round; on the other hand, that of cells surrounded strands was elongated. When cooked in boiling water or soaked at pH 2.0, the shape of the former cells was maintained, but the latter cells, which contributed to adhesion between strands, broke down. Thus, the flesh separated into strands. When flesh was boiled for 15-30 min, pectin degraded and dissolved in the cooking solution; consequently, the flesh separated into strands and also the middle lamella of cell walls of strands separated. However, pectin remaining in strands maintained their crispness.  相似文献   
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Journal of Inorganic and Organometallic Polymers and Materials - In recent times, the global demand for multi-biofunctional tissue scaffolds is rising gradually. The present study deals with the...  相似文献   
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