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21.
22.
EP Groody 《Canadian Metallurgical Quarterly》1996,6(3):323-327
The detection of foodborne microorganisms has traditionally been done using microbiologically based methods. Such "gold standard" methods are generally reliable but have the disadvantages of being labor intensive, subjective, and time consuming. Over the last several years, the development of DNA probe-based methods has simplified the methods used to detect organisms such as Salmonella, Listeria, and E. coli by targeting the unique DNA or RNA sequences of these organisms using DNA probes and nonradioactive detection. 相似文献
23.
V. A. Bashkin 《Programming and Computer Software》2010,36(4):187-196
A new method for modeling distributed systems—nets of active resources—is presented. The expressive power of this formalism
is similar to that of ordinary Petri nets, but its syntax relies on a different modeling principle: instead of partitioning
model components (nodes of the graph) into agents and resources (transitions and places), partitioning of the ways of interaction
(arcs of the graph) in terms of production and consumption is introduced. Direction of an arc determines whether the interaction
is active or passive: one and the same component upon different firings may play role of both an agent and a resource. In
nets of active resources and their syntactic extensions, there appears an opportunity for convenient formalization of various
semantic properties, such as simultaneous work of agents, agent blocking, redundancy of the number of agents, a possibility
of replacement of an unreliable node by a reliable one, and the like. A method for constructing distributed applications based
on dynamically configured sets of executable modules is considered. It is shown that the use of nets of active resources allows
one to specify their structure, as well as to formulate properties of such systems, in a natural way. 相似文献
24.
We have previously demonstrated that mouse brain membrane fractions have a specific, saturable receptor for diadenylated nucleotides. Binding is specific for two adenosines, and the length of the phosphate bridge is critical, with four phosphates being optimal [Hilderman et al. (1991) J. Biol. Chem. 266, 6915-6918]. In this report, we demonstrate that adenosine 5',5"'-P1,P4-tetraphosphate (Ap4A) binding to its receptor is dependent upon an activation step that requires divalent cations and a serine protease. Monoclonal antibodies (Mabs) are identified that inhibit Ap4A binding to its membrane receptor. These antibodies recognize a 212-kDa membrane protein. However, SDS-PAGE analysis of Ap4A cross-linked to membrane fractions reveals that Ap4A is not attached to the 212-kDa peptide but to a 30-kDa polypeptide. Appearance of the 30-kDa polypeptide is dependent on the activation step, and one of the inhibitory antibodies blocks its appearance. We suggest that the protease-dependent processing step involves cleavage of the 212-kDa component with the appearance of an active 30-kDa receptor. 相似文献
25.
The decomposition of petroleum hydrocarbons in gray forest soil (Moscow oblast) under the action of peat compost was evaluated under model conditions. It was noted that the decomposition of hydrocarbons increased simultaneously with an increase in the activity of catalase and dehydrogenase enzymes, which directly participate in this process. 相似文献
26.
Bashkin JK 《Chemical reviews》2000,100(12):4265-4266
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EP Nacheva CD Grace M Bittner DH Ledbetter RB Jenkins AR Green 《Canadian Metallurgical Quarterly》1998,100(2):93-105
A comparative analysis of the differentiation pattern, the proliferative behaviour, and the level of apoptosis between human benign and malignant neoplasms of smooth-muscle (SM) tissue is lacking. The clinical, histopathological, immunochemical, and immunocytochemical features of leiomyomas (LM) and leiomyosarcomas (LMS) were investigated by a panel of monoclonal antibodies specific for some differentiation markers of SM tissue (SM myosin and alpha-actin, desmin, and SM22) and for markers of non-muscle tissue (vimentin and non-muscle myosin). Proliferating normal and neoplastic cells were identified by proliferating-cell nuclear antigen (PCNA)/Ki67 immunostainings and the apoptotic cells were revealed by means of the terminal-deoxynucleotidyltransferase-mediated dUTP nick-end labelling technique. Gel electrophoresis and Western blotting, performed with anti-(SM1/SM2 myosin isoform) antibody, indicated quantitative differences between LMS and LM, which mirrored higher positive to negative nuclear ratios for PCNA, Ki67 and apoptosis in malignant as opposed to benign neoplasms. With LM, however, a similar SM1 to SM2 ratio could be associated with different proliferation levels. Uterine, gastric and intestinal LMS displayed specific patterns of SM1/SM2 and/or non-muscle myosin expression that were not paralleled by different levels of proliferation/apoptosis. While the level of PCNA/Ki67 correlated with the level of apoptosis in normal SM tissues and LM, that of LMS did not. In vivo at the cellular level, LM and uterine LMS displayed a near-uniform SM tissue differentiation, whereas the other LMS displayed a lesser or a heterogeneous immunoreactivity. In vitro, cultured LMS cells showed a limited and peculiar expression of SM myosin. In conclusion, there is no reciprocal relationship between degree of differentiation and the level of proliferation, as exemplified by the finding that the less differentiated intestinal LMS displays the lowest proliferative behaviour and that the relatively more differentiated gastric LMS/metastasis is more proliferative. 相似文献
30.
To evaluate the clinical significance of serum levels of hepatocyte growth factor (HGF) in colorectal cancer patients, we measured the venous and portal concentrations of HGF in 60 patients. The tissue concentrations in the tumour and adjacent normal mucosa were also determined. The serum HGF concentration for the peripheral venous blood of the patients was significantly higher than that in normal controls. The content of HGF in cancer tissue was also significantly higher than that in normal mucosa, and it was correlated with the serum HGF concentration for the peripheral venous blood. The serum concentration of HGF reflected pathological features, including tumour size and lymph node or liver metastasis, and it showed an association with various preoperative nutritional parameters and the preoperative haemoglobin level. The serum HGF concentration was also correlated with the serum concentrations of immunosuppressive acidic protein and interleukin-6, indices of the host's immunological condition. Serum HGF seems to be a useful index of the disease status of patients with colorectal carcinoma. 相似文献