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1.
In 4 experiments, rats received 1 of several outcomes for engaging in various instrumental responses in the presence of discriminative stimuli. Discriminative stimuli shared some response-outcome relations but not others. When a response was subsequently extinguished in the presence of 1 discriminative stimulus, that produced relatively more decrement in responding in other stimuli that shared the same response-outcome relation. Other discriminative stimuli, in the presence of which that response had been reinforced by other outcomes and in which the original outcome had reinforced another response, were less affected. Moreover, postextinction devaluation of that outcome suggested that the particular response-outcome relation extinguished had undergone decrement. These results suggest that discriminative stimuli have relatively specific associations with the response-outcome relations that obtain in their presence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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BACKGROUND: The terminal Gal alpha1,3Galactose (alphaGal) determinant is present on all porcine glycoproteins and glycolipids, but is not expressed by human cells. Consequently human sera contain anti-alphaGal natural antibodies. The human blood group B antigen [Gal alpha1,3(Fuc1,2)Galactose] is differentiated from the alphaGal epitope by the presence of a fucosyl group. METHODS: To determine whether the expression of the B antigen has any effect on the level of alphaGal-reactive natural antibodies, equal numbers (n=12) of A, B, AB, and O serum samples were evaluated by ELISA and flow cytometry. RESULTS: A significant reduction in IgG alphaGal reactivity was observed with serum samples from B antigen-expressing donors (B, AB) relative to non-B antigen-expressing donors (A, O). CONCLUSIONS: These results are consistent with the possibility that anti-alphaGal antibodies in non-B antigen-expressing individuals include a subset that is reactive with the structurally related B antigen and that this subset is absent in B and AB individuals.  相似文献   

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According to construal level theory (N. Liberman, Y. Trope, & E. Stephan, in press; Y. Trope & N. Liberman, 2003), people use a more abstract, high construal level when judging, perceiving, and predicting more psychologically distal targets, and they judge more abstract targets as being more psychologically distal. The present research demonstrated that associations between more distance and higher level of construal also exist on a pure conceptual level. Eight experiments used the Implicit Association Test (IAT; A. G. Greenwald, D. E. McGhee, & J. L. K. Schwartz, 1998) to demonstrate an association between words related to construal level (low vs. high) and words related to four dimensions of distance (proximal vs. distal): temporal distance, spatial distance, social distance, and hypotheticality. In addition to demonstrating an association between level of construal and psychological distance, these findings also corroborate the assumption that all 4 dimensions of psychological distance are related to level of construal in a similar way and support the notion that they all are forms of psychological distance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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In the ABO blood group system, several subgroups have been described based on: 1) the difference of reactivities of the red cells with anti-A, anti-B, anti-A1, and anti-H, 2) the presence or absence of anti-A, anti-B, anti-A1, anti-H, and anti-HI in serum, and 3) the presence of A, B, H substances in the saliva of ABH secretors. Subgroups of A are more frequent in Caucasians than in Japanese, while those of B are more frequent in Japanese. Both the red cell typing (testing red cells for A and B antigens) and serum typing (testing the antibodies in the serum against red cells of known ABO groups) are important to identify and not to overlook these ABO subgroups. When transfusion is required in individuals with these subgroups, compatible blood products must be selected according to the presence or absence of antibodies active at 37 degrees C.  相似文献   

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Because of the strong association of active smoking with fetal growth retardation, increasing interest has focused on whether there is also an association with exposure to environmental tobacco smoke (ETS). We examined this issue in a retrospective study and by conducting a review of the literature and data pooling. In our study, nonsmoking women with singleton livebirths born in 1986-87 (n = 992) provided information on exposure to ETS for 1 h or more per day and paternal smoking. The risk of low birthweight (LBW, < 2500 g) was not increased in infants of ETS-exposed women, but there was a somewhat increased risk for LBW at term (adjusted odds ratio [OR] 1.8, 95% confidence interval [CI] 0.6, 4.8) and small-for-gestational-age (< 10th percentile of weight; OR = 1.4, 95% CI = 0.8, 2.5). These results were in the range of 16 other studies in the literature that had odds ratios from 1.0 to 2.2. A weighted average of the results of all studies on LBW at term or small-for-gestational-age yielded a pooled estimate of 1.2 [95% CI = 1.1, 1.3] in nonsmoking women. The pooled estimate of mean birthweight indicated a decrement of 28 g with ETS exposure of nonsmoking women [95% CI = -41, -16], with a greater decrement (about 40 g) seen among more homogeneous studies.  相似文献   

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Occurrence and distribution of glycoprotein H substances in blood type O human erythrocyte membrance were studied using an alpha N-acetylgalactosaminyltransferase (A-enzyme) purified from milk of blood type A women. Erythrocytes of blood group O, nonsecretors and secretors alike, contain H substances that serve as a substrate for this transferase, and the H determinants seem to occur in all three erythrocyte membrane glycoproteins (periodic acid-Schiff (PAS)-1, PAS-2, and PAS-3). Structural studies of the A glycoproteins obtained by the transferase action, suggested that all erythrocyte H glycoproteins contain only type 2 antigenic determinant.  相似文献   

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We have encountered a paternity case where exclusion of the putative father was only observed in the ABO blood group (mother, B; child, A1; putative father, O), among the many polymorphic markers tested, including DNA fingerprints and microsatellite markers. Cloning a part of the ABO gene, PCR-amplified from the trio's genomes, followed by sequencing the cloned fragments, showed that one allele of the child had a hybrid nature, comprising exon 6 of the B allele and exon 7 of the O1 allele. Based on the evidence that exon 7 is crucial for the sugar-nucleotide specificity of A1 and B transferases and that the O1 allele is only specified by the 261G deletion in exon 6 of the consensus sequence of the A1 allele, we concluded that the hybrid allele encodes a transferase with A1 specificity, resulting, presumably, from de novo recombination between the B and O1 alleles of the mother during meiosis. Screening of random populations demonstrated the occurrence of four other hybrid alleles. Sequencing of intron VI from the five hybrid alleles showed that the junctions of the hybrid alleles were located within intron VI, the intron VI-exon 7 boundaries, or exon 7. Recombinational events seem to be partly involved in the genesis of sequence diversities of the ABO gene.  相似文献   

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ABO genotyping was carried out using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) method on the dried remains of nine human mummies which had been discovered at Taklamakan desert in 1912. In all the nine mummies, ABO genotype could be determined as BO type, and ABO phenotype of the eight mummies with hair specimen could be revealed as B type using absorption-elution method. These results mean that ABO phenotype estimated from its genotype by PCR-RFLP was consistent with that by absorption-elution method in all of the eight cases examined. And in the other one child mummy, ABO phenotype could not be examined because of no hair specimen. Although it is impossible to assess the allele frequency of ABO blood group system in the populations having lived in Gao Chang at that time, the present study shows a possibility of ABO genotyping from ancient human remains.  相似文献   

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The ahthors present new data on the character of the vaccine process in children associated with the characteristics of the blood group ABO, MNSs and Rh systems. The greater frequency of occurrence and more manifest reactions were noted in children with blood groups A, B, AB, M and Rho (D) - in comparison with those having blood groups O, Rho (D) +, MN and N. There was a significant prevalence of chromosomal aberrations in the primarily immunized children with blood groups A in comparison with groups O, B and AB. The data obtained pointed to the negative effect of the mimi-rating antigens of the smallpox virus on the immunogenesis in smallpox. Search for methods of releasing the vaccine of these antigens is necessary for reduction of the reactogenic properties and increase of immunogenecity of the smallpox vaccines.  相似文献   

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We have encountered an allele which seems to be another type of O allele at the human histo-blood group ABO locus. We have determined the nucleotide sequence of this allele over the coding region in the last two coding exons. This allele does not possess the single-nucleotide deletion found common among all the O alleles previously analyzed. Compared with A1 allele, this allele has three nucleotide substitutions resulting in two amino acid substitutions. The introduction of these amino acid substitutions into the A1 transferase expression construct apparently abolished the enzymatic activity of A1 transferase.  相似文献   

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The results of this study indicate that tobacco smoking may have a deleterious effect on the learning process. One hundred and fifteen male volunteers were assessed on four learning tasks. Those Ss who smoked in excess of 12 cigarettes per day did significantly less well, as a group, than nonsmokers and light smokers on three of the four learning tests.  相似文献   

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The crucial issues in a policy debate are often matters of perception and interpretation rather than fact, and the values and norms that influence perceptions are central to an understanding of conflict in the policy arena. For example, science's norms of objectivity and disinterestedness are being modified today to accommodate closer academic-industry ties. The author traces in detail how these ties and the accompanying public distrust have developed, beginning with the post-World-War-II increase in public support for basic research and continuing with subsequent pieces of legislation that lowered the barriers between academic and industrial research in order to reap economic benefits. He then analyzes the impact of financial incentives in university-industry relationships on science and on public perceptions of science, and the price both science and the public would pay if the public loses trust in science and refuses to support it. He also reviews the history of the ill-fated National Institutes of Health guidelines for university-industry collaborations proposed in 1979 and the subsequent history of the policy on this topic recently adopted by the Public Health Service. He maintains that the PHS policy poses both a risk (the temptation to enforce the policy loosely) and an opportunity (for research institutions to grasp the initiative and develop meaningful conflict-of-interest guidelines of their own). But the policy falls short of responding to the much broader range of concerns associated with university-industry research collaboration, for example, the possible effects of such collaboration on the traditional openness and sharing among scientists. The available data on these effects are mixed. He concludes by maintaining that scientists and their industry partners should address the issues surrounding their collaboration now rather than waiting for negative events to trigger public arousal and force a mutually unsatisfying political solution. This article is one of three in this issue of Academic Medicine that deal with issues of conflict of interest in university-industry research relationships. These articles are discussed in an overview that precedes them.  相似文献   

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