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121.
In prokaryotes, DnaK-DnaJ chaperon is involved in the protein degradation catalyzed by proteases La and ClpA/B complex as shown in E. coli. To extend this into eukaryotic cells, we examined the effects of hsp70 genes, SSA1 and SSB1, and DnaJ genes, SIS1 and YDJ1, on the growth of proteasome subunit mutants of the yeast S. cerevisiae. The results identified SSB1 and SIS1 as a pair of chaperon genes specifically involved in efficient protein turnover in the yeast, whose overexpression suppressed the growth defects caused by the proteasome mutations. Moreover, a single amino acid substitution in the putative peptide-binding site of SSB1 protein profoundly enhanced the suppression activity, indicating that the activity is mediated by the peptide-binding activity of this chaperon. Thus SSB1, with its partner DnaJ, SIS1, modulates the efficiency of protein turnover through its chaperon activity. 相似文献
122.
The vigilance reaction is characterized by a large bradycardia, a pressor response, and inspiratory apnea in anesthetized rabbits and the inhibition of movement in conscious rabbits. This affective response pattern can be elicited by electrical stimulation of the dorsolateral hypothalamus (the hypothalamic vigilance area) or the ventrolateral periaqueductal gray (the periaqueductal gray vigilance area). The present study sought to advance our understanding of the functional relationship between the hypothalamic vigilance area (HVA) and the periaqueductal gray vigilance area (PVA) by measuring the effects of transverse transections of the caudal portion of the ventrolateral PAG (vlPAG) upon the cardiovascular responses elicited from the dorsolateral hypothalamus and the rostral vlPAG. Selective transverse transections of the caudal vlPAG significantly reduced the magnitudes of the bradycardia and pressor response elicited by stimulation of the PVA rostral to the transection site, but had minimal impact on the cardiovascular responses evoked by stimulation of the HVA. These findings suggest that the cardiovascular responses elicited by stimulation of the vlPAG are mediated by a neural pathway that is parallel, at least in part, to the one that subserves the response elicited from the HVA. The results also provide support for the view that the PAG is not an essential structure in the mediation of the autonomic components of affective behaviors involving behavioral inhibition. 相似文献
123.
Fundamental formulas, which, within the framework of the physical model employed, describe the generation and measurement
of electric field strength, are presented.
__________
Translated from Izmeritel'naya Tekhnika, No. 8, pp. 44–47, August, 2008. 相似文献
124.
L. A. Angolenko G. D. Semchenko S. V. Tishchenko V. N. Sidorov 《Refractories and Industrial Ceramics》2009,50(1):52-56
Oxidation resistance has been examined for compacted Al2O3–SiC–C mixtures, which contain an aluminum-chromium-phosphate binder without firing (DTA method) and ones that have been previously
fired and given isothermal heat treatment at 800°C (as indicated by the mass loss). To obtain oxidation-resistant materials,
the content of silicon carbide should not exceed 10 wt.% and the recommended graphite content is not more than 20 wt.%.
Translated from Novye Ogneupory, No. 2, pp. 38 – 43, February, 2009. 相似文献
125.
L. A. Angolenko G. D. Semchenko S. V. Tishchenko O. V. Stepanyuk 《Refractories and Industrial Ceramics》2007,48(5):368-372
A set of studies is presented for the physicomechanical properties of corundum-graphite carbide-containing refractories. The
efficiency of introducing silicon carbide as an antioxidant addition to Al2O3-SiC2-C-materials is established. The structure and phase composition of corundum-graphite silicon carbide-containing refractories
based on an ethyl silicate binder fired in a reducing atmosphere are studied.
__________
Translated from Novye Ogneupory, No. 10, pp. 52–56, October 2007. 相似文献
126.
A theoretical analysis of the operation of a thin radiating biconical antenna is given. Formulas are obtained for the current
distribution in the antenna and its input impedance.
__________
Translated from Izmeritel’naya Tekhnika, No. 1, pp. 43–47, January, 2008. 相似文献
127.
P Klootwijk S Meij GA von Es EJ Müller VA Umans T Lenderink ML Simoons 《Canadian Metallurgical Quarterly》1997,18(6):931-940
AIMS: The selection of ECG leads used for ST monitoring may influence detection and quantitation of ischaemia. METHODS: We compared on-line continuous 48-h 12-lead against 3-lead ST monitoring in 130 unstable angina patients (Mortara. ELI-100). Onset and offset of ST episodes were defined by the lead with the first > or = 100 microV ST change relative to baseline and the lead with the latest return to baseline ST level, respectively. ST episodes were calculated for 12 leads and 3 leads (V2, V5, III) separately. RESULTS: ST episodes were detected in 88 patients (77%) by 12-lead and in 71 patients (62%) by 3-lead ST monitoring (P < 0.02). The median number (25.75%) of episodes/patient was 1 (0.3) for 3-lead and 2 (1.6) for 12-lead (P < 0.0001). The total duration of ischaemia detected during 12-lead far exceeded 3-lead monitoring: 12.3 (1, 58.2) and 1.7 (0, 23.3) min respectively (P < 0.0001). The probability of recurrent ischaemia declined most during the first 24 h of monitoring. After a period without ST changes of 1, 12, 24 and 36 h, the probabilities of recurrent ischaemia were 63, 31, 14 and 9%, respectively. CONCLUSIONS: Continuous 12-lead ST monitoring increases detection rate and duration of ST episodes compared to 3-lead ST monitoring. The use of continuous 12-lead ECG monitoring devices on emergency wards and coronary care units is recommended. 相似文献
128.
An exact solution has been obtained to the integral equation for the current in a frame antenna built with an infinitely narrow gap. The total current at the input is infinite because of the infinite capacity of the gap and the finite thickness of the antenna. 相似文献
129.
AV Feofanov VA Ole?nikov AB Tuzikov AI Ianul' EIu Kriukov NV Bovin IR Nabiev 《Canadian Metallurgical Quarterly》1997,23(11):910-918
Neoglycoconjugates based on polyacrylamide and sialic acid with N-acetylneuraminic acid or sialooligosaccharides as side chains were studied by surface-enhanced Raman scattering (SERS) spectroscopy. It had previously been found that these polymers can effectively inhibit influenza virus adhesion. This study revealed the possibility to evaluate, based on the intensity of SERS signals, the overall availability for interaction and the conformational freedom of sialic acid residues in glycoconjugates. The dependence of these two factors on the structure and density of sialylated side chains was studied. The uniformity of distribution of sialylated side chains in conjugates was shown. Comparison of the results of the SERS spectroscopic study of the conjugates and the data on their inhibitory effect on the adhesion of specific strains of influenza virus allowed the identification of the conjugates for which the availability and conformational freedom of sialic acid are the main factors determining their inhibitory properties. A conclusion was also reached about the predominance of one of the mechanisms (competitive inhibition or steric stabilization) in the inhibitory properties of the specific conjugates. 相似文献
130.