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Pr6O11 nanoparticles were obtained by subsequent thermal decomposition of the as-prepared precipitate formed under ambient temperature and pressure using NaOH as precipitant.The calcination process was affected,for 1 h in static air atmosphere,at 400-700 °C temperature range.The different samples were characterized using X-ray diffraction(XRD),transmission electron microscopy(TEM),field emission scanning electron microscopy(FE-SEM),thermogravimetric analysis(TGA),in situ electrical conductivity,and N 2 adsorption/desorption.The obtained results demonstrated that nano-crystalline Pr6O11,with crystallites size of 6-12 nm,started to form at 500 °C.Such value increased to 20-33 nm for the sample calcined at 700 °C.The as-synthesized Pr6O11 nanoparticles presented high electrical conductivity due to electron hopping between Pr(III)-Pr(IV) pairs.  相似文献   

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Thrombopoietin (Mpl ligand), interleukin-6 (IL-6), and interleukin-11 (IL-11) differ in their effects on megakaryocyte maturation and development. In the present study, the impact of these thrombocytopoietic cytokines on biochemical and structural granule and membrane components was examined. Western blotting was performed on equivalent amounts of isolated megakaryocyte or platelet protein and the relative intensities of the enhanced chemiluminescent-visualized bands were quantitated by densitometry. Megakaryocyte growth and development factor (MGDF), a recombinant thrombopoietin-related molecule, significantly increased megakaryocyte fibronectin (72%), thrombospondin (55%), von Willebrand factor (28%) and p-selectin (CD62p) (37%) when compared to equivalent amounts of protein from saline-treated controls (p<0.01). Megakaryocyte fibrinogen was not increased. Ultrastructurally, there was a marked increase in ribosomes and rough endoplasmic reticulum even in mature-appearing megakaryocytes. Platelets from MGDF-treated mice showed small increases in fibronectin (8%), and CD62p (18%), but did not show increases in other measured alpha-granule proteins. Neither IL-6 nor IL-11 increased megakaryocyte or platelet alpha-granule proteins over levels observed in saline controls. IL-11 treated megakaryocytes, while also exhibiting an increase in ribosomes, were characterized by prominent cytoplasmic fragmentation. The study demonstrates the impact of Mpl ligand in increasing synthesized megakaryocyte alpha-granule proteins and of IL-11 in promoting megakaryocyte fragmentation.  相似文献   

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Elaiophylin (1) and two new methyl derivatives, 11-O-monomethylelaiophylin (2) and 11,11'-O-dimethylelaiophylin (3), were isolated from the mycelium cake of Streptomyces strains HKI-0113 and HKI-0114. The structures of 2 and 3 were determined by mass spectrometric and NMR investigations. Compounds 2 and 3 display antimicrobial and moderate cytotoxic activities.  相似文献   

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Vulvar vestibular biopsy specimens from 31 women with clinical and pathologic findings of vulvar vestibulitis were studied using polymerase chain reaction (PCR) for the identification of human papilloma virus (HPV). The PCR technique specifically probed for HPV types 6, 11, 16, and 18. Of the 31 subjects, three were found to have HPV within the biopsy specimens; two had HPV type 11 and one had HPV 16. Five of the 31 cases had histopathologic features of koilocytosis consistent with HPV effect; three of these five were found to have HPV. The findings support the hypothesis that HPV types 6, 11, 16, and 18 are rarely associated with vulvar vestibulitis. The frequencies identified were similar to those seen with control patients. True koilocytosis is the most useful pathologic feature distinguishing HPV-related cases; it is rarely identified in typical vulvar vestibulitis. Nonspecific changes in the vestibular epithelium associated with glycogen effect should not be interpreted as koilocytosis.  相似文献   

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We analysed a complex translocation involving chromosomes 5, 6, 8 and 11 in a case of infant leukemia. Molecular analysis of the MLL gene revealed that MLL was fused with two different genes, AF-6 on chromosome 6q27 and AF-5alpha. AF-5alpha, the 11th partner gene fused with MLL, is a novel gene mapped to chromosome 5q12, which encodes a 31 kDa protein of 269 amino acids and contains a possible nuclear targeting sequence, a potential leucine zipper dimerization motif and an alpha-helical coiled-coil domain. In situ hybridization and molecular cloning analyses demonstrated that two different types of chromosomal recombination had occurred in the cells. One was a three-way translocation among chromosomes 6, 8 and 11, and the other was an insertion of a chromosome 5-derived segment into the breakpoint of chromosomes 8 and 11. Accordingly, the karyotype was defined as del(5)(q11.2q12), der(6)t(6;8) (q27;q11.2), der(8)(8pter-->8q11.2::5q11.2-->5q12::11q23-->++ +11qter), der(11)t(6;11) (q27;q23). Thus, the MLL gene created two different fusion mRNAs, since the chromosome 11 split into two different chromosomes 5 and 6. This is the first report demonstrating fusion of the MLL gene with two different genes by a complex translocation.  相似文献   

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Allelotype analysis of human tumors has been instrumental in the effort to discover and clone novel tumor suppressor genes. However, this approach has not been systematically applied to animal models of carcinogenesis. We describe here the first attempt to allelotype a nonhuman tumor, i.e., chemically induced mouse skin tumors, using a panel of polymorphic microsatellite markers. The results indicated that markers on chromosomes 6 and 7 were imbalanced, consistent with trisomy in both benign and malignant skin tumors. A proportion of carcinomas also showed loss of heterozygosity on chromosome 11, where the p53 gene is located, and more rarely, on chromosomes 4, 6, and 15. The significance of these alterations is highlighted by the observations of no allelic imbalance for markers on 12 other chromosomes.  相似文献   

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The time-dependent loss of the 7-ethoxy-4-trifluoromethylcoumarin (EFC) O-deethylase activity of rat P450 2B1, rabbit P450 2B4, or dog P450 2B11 by 1-ethynylnaphthalene (1EN), 2-ethynylnaphthalene (2EN), 2-(1-propynyl)naphthalene (2PN), 1-ethynylanthracene (1EA), 2-ethynylanthracene, 2-ethynylphenanthrene, 3-ethynylphenanthrene, 9-ethynylphenanthrene (9EPh), 9-(1-propynyl)phenanthrene (9PPh), 4-ethynylpyrene (4EP), and 4-(1-propynyl)biphenyl (4PbP) was investigated. The rate constants for inactivation by the arylalkynes in descending order of effectiveness for the top five compounds were 9EPh>9PPh>1EN, 2EN, 2PN for 2B1, 9EPh>2EN>4EP>1EN, 1EA for 2B4, and 9EPh>1EA>4EP, 9PPh>2EN for 2B11. The size and the shape of the aromatic ring system and the placement of the alkyne functional group were important for inactivation. The most effective inactivator with all the isozymes was 9EPh. This compound also inactivated the EFC activity in microsomes from human lymphoblastoid cells expressing human P450 2B6. The specificity of 9EPh for the inhibition or inactivation of different P450 activities in microsomes from rats treated with various inducing agents was determined by measuring lidocaine, testosterone, p-nitrophenol, or erythromycin metabolism. The greatest effect was observed with the 2B-specific products from lidocaine and testosterone, whereas no effect was seen with p-nitrophenol or erythromycin. When the covalent binding of [3H]2EN to microsomal protein was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography, a radiolabeled protein band that corresponds to 2B1 was observed in the lanes containing microsomes from rats treated with phenobarbital and, to a lesser extent, pyridine and isosafrole after incubation with NADPH. When these microsomes were incubated with [3H]9EPh or [3H]1EP, two NADPH-dependent bands were radiolabeled. One corresponded to 2B1/2 and the other to a protein of approximately 59 kDa, which was observed in the lanes from phenobarbital-treated male and female rats and pyridine-treated male rats. No radiolabeled bands were observed with [3H,14C]4PbP with any of the microsomes.  相似文献   

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AsakindofHPC (highprotonconduc tor)materials ,POMs (polyoxometalates)havereceivedmuchattentionrecentlyforitshigherprotonconductivitiesatroomtemperatureandloweractivationenergy[1 ,2 ] .However ,thepropertyoflosingwatersatmoderatecondition(about 6 0℃ )limitsitsappl…  相似文献   

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The effect of thermally cycling in air with no applied load was studied using the Ti-24A1-11Nb (atomic percent)/SCS-6 composite system. Mechanisms of damage determination were observable cracking and residual tensile properties. Either the number of cycles or the temperature range was varied from specimen to specimen. Effects of number of cycles were investigated using a temperature range of 150 °C to 815 °C. Comparisons of temperature range effects were made at a constant cycle count of 500. Matrix cracking was observed at a †T of 450 °C and greater when oxidation was significant. Transverse cracking was not observed in specimens that were cycled to maximum temperatures where oxidation was insignificant, even for †T's as large as 500 °C. A decrease in tensile properties coincided with the observed transverse matrix cracking. This paper is based on a presentation made in the symposium “Interfaces and Surfaces of Titanium Materials” presented at the 1988 TMS/AIME fall meeting in Chicago, IL, September 25–29, 1988, under the auspices of the TMS Titanium Committee.  相似文献   

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Conducted 2 experiments to investigate the 1st author's cognitive theory of secondary reinforcement effects, which predicts that Ss of a preoperational age (i.e., younger than 7 yrs) should not necessarily learn responses followed by a stimulus object previously instrumental in obtaining a reward, while Ss of a postoperational age should do so. Using 24 1st and 24 5th graders in 2 learning tasks, the prediction was confirmed. Furthermore, verbal responses indicated that the logical operations that presumably influenced the behavior of the older children actually did occur. In Exp II, using 28 2nd and 15 6th graders, the training task was simplified in order to try to facilitate logical reasoning, but the behavior of the younger Ss was not affected. It is concluded that secondary reinforcement of a stimulus–response associative type has yet to be demonstrated, and that secondary reinforcement of a cognitive type is heavily dependent on reasoning ability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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