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21.
TG Benedek 《Canadian Metallurgical Quarterly》1993,11(1):53-59
Previous work has shown that exposure to many non-mutagenic stresses causes greater UV resistance in Escherichia coli K12 via an error-free, excision repair-dependent process. Induction of the latter should enhance liquid holding recovery in the bacteria. The results in this paper show that this is the case and that the increased UV-resistance is due entirely to an increase in the capacity of the cells for DNA excision repair. The latter arises wholly or in part from an increase in the intracellular level of the key enzyme of the pathway, UvrABC endonuclease. 相似文献
22.
The contribution of nitric oxide (NO) to capsaicin-evoked plasma extravasation was studied in rat hindpaw skin. Two inhibitors of NO synthase were used: 7-nitroindazole, with a selectivity for nerve-derived NO, and the L-arginine derivative, N(omega)-nitro-L-arginine (L-NOARG), which is a non-selective inhibitor. Plasma extravasation was induced by intraplantar injection of 5 microg/50 microl capsaicin and measured by the Evans blue leakage technique. Both acute and chronic administration of 7-nitroindazole significantly reduced capsaicin-evoked plasma extravasation in rat hind-paw skin, whereas L-NOARG enhanced it. This enhancement was abolished non-stereospecifically by either L- or D-arginine. Our results suggest that NO production from different sources yields a complex action in maintaining the endothelial integrity in neurogenic plasma extravasation. 相似文献
23.
László Benedek 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1937,74(4):297-302
Zusammenfassung In den paprikaanbauenden Gegenden, so in Szeged und Kalocsa ist die Tatsache bekannt, daß von mit Paprikaabfällen gefütterten Hühnern gelegte Eier einen rötlich gefärbten Dotter haben. Solche Eier sind infolge ihrer erhöhten Farbkraft sehr beliebt und werden von Hausfrauen sowie von Teigwarenfabrikanten gerne gekauft und sogar mit höheren Preisen bezahlt. Im Laufe meiner Versuche beabsichtigte ich, die Höhe der Ablagerung des roten Farbstoffes im Dotter festzustellen. Die quantitativen Verhätnisse der Farbstoffablagerung wurden auf colorimetrischem Wege geprüft, und zwar auf Grund einer willkürlich gewählten colorimetrischen Einheit, die der Farbtiefe einer 0,02 proz. Kaliumbichromatlösung von 100 mm Schichtdicke entsprach. Wie es aus den mitgeteilten Tabellen zu entnehmen ist, trat die rötliche Dotterfärbung bald auf und stieg im Laufe der Fütterung auf das Mehrfache des zuerst untersuchten Eies. Während der Versuchszeit konnte an den Hühnern keine physiologische Änderung wahrgenommen werden. Die mitgeteilte Erscheinung könnte vielleicht im Winter zur Zeit des Grünfuttermangels eine praktische Bedeutung erlangen. 相似文献
24.
Lithium reactions with intermetallic-compound electrodes 总被引:3,自引:0,他引:3
Intermetallic compounds are under investigation as possible anode materials in lithium batteries. The compounds on which the Argonne National Laboratory group has primarily focused were selected on the basis of structural compatibility between host and product (lithiated) phases. In this presentation, we discuss the additional insights into the behavior of intermetallic-compound anodes that are available from materials modeling. 相似文献
25.
G. Benedek R. E. Grisenti M. Käsz J. P. Toennies 《Journal of Low Temperature Physics》2007,146(3-4):393-402
The regular periodic intensity bursts recently observed in the expansion of solid 4He into vacuum have anomalies that have been attributed to a transition to some new solid phase induced by excess vacancies.
Here it is shown that a small concentration of 3He, from 1% down to 0.1%, added to the 4He solid is sufficient to remove all the anomalies. The origin of the observed anomalies is discussed in the light of these
new experiments.
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DC Kadunce JW Vaughan MT Wallace G Benedek BE Stein 《Canadian Metallurgical Quarterly》1997,78(6):2834-2847
The present studies were initiated to explore the basis for the response suppression that occurs in cat superior colliculus (SC) neurons when two spatially disparate stimuli are presented simultaneously or in close temporal proximity to one another. Of specific interest was examining the possibility that suppressive regions border the receptive fields (RFs) of unimodal and multisensory SC neurons and, when activated, degrade the neuron's responses to excitatory stimuli. Both within- and cross-modality effects were examined. An example of the former is when a response to a visual stimulus within its RF is suppressed by a second visual stimulus outside the RF. An example of the latter is when the response to a visual stimulus within the visual RF is suppressed when a stimulus from a different modality (e. g., auditory) is presented outside its (i.e., auditory) RF. Suppressive regions were found bordering visual, auditory, and somatosensory RFs. Despite significant modality-specific differences in the incidence and effectiveness of these regions, they were generally quite potent regardless of the modality. In the vast majority (85%) of cases, responses to the excitatory stimulus were degraded by >/=50% by simultaneously stimulating the suppressive region. Contrary to expectations and previous speculations, the effects of activating these suppressive regions often were quite specific. Thus powerful within-modality suppression could be demonstrated in many multisensory neurons in which cross-modality suppression could not be generated. However, the converse was not true. If an extra-RF stimulus inhibited center responses to stimuli of a different modality, it also would suppress center responses to stimuli of its own modality. Thus when cross-modality suppression was demonstrated, it was always accompanied by within-modality suppression. These observations suggest that separate mechanisms underlie within- and cross-modality suppression in the SC. Because some modality-specific tectopetal structures contain neurons with suppressive regions bordering their RFs, the within-modality suppression observed in the SC simply may reflect interactions taking place at the level of one input channel. However, the presence of modality-specific suppression at the level of one input channel would have no effect on the excitation initiated via another input channel. Given the modality-specificity of tectopetal inputs, it appears that cross-modality interactions require the convergence of two or more modality-specific inputs onto the same SC neuron and that the expression of these interactions depends on the internal circuitry of the SC. This allows a cross-modality suppressive signal to be nonspecific and to degrade any and all of the neuron's excitatory inputs. 相似文献