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排序方式: 共有652条查询结果,搜索用时 15 毫秒
1.
Bruce Y. Lee Sarah M. Bartsch Marie C. Ferguson Patrick T. Wedlock Kelly J. OShea Sheryl S. Siegmund Sarah N. Cox James A. McKinnell 《PLoS computational biology》2021,17(1)
Finding medications or vaccines that may decrease the infectious period of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could potentially reduce transmission in the broader population. We developed a computational model of the U.S. simulating the spread of SARS-CoV-2 and the potential clinical and economic impact of reducing the infectious period duration. Simulation experiments found that reducing the average infectious period duration could avert a median of 442,852 [treating 25% of symptomatic cases, reducing by 0.5 days, reproductive number (R0) 3.5, and starting treatment when 15% of the population has been exposed] to 44.4 million SARS-CoV-2 cases (treating 75% of all infected cases, reducing by 3.5 days, R0 2.0). With R0 2.5, reducing the average infectious period duration by 0.5 days for 25% of symptomatic cases averted 1.4 million cases and 99,398 hospitalizations; increasing to 75% of symptomatic cases averted 2.8 million cases. At $500/person, treating 25% of symptomatic cases saved $209.5 billion (societal perspective). Further reducing the average infectious period duration by 3.5 days averted 7.4 million cases (treating 25% of symptomatic cases). Expanding treatment to 75% of all infected cases, including asymptomatic infections (R0 2.5), averted 35.9 million cases and 4 million hospitalizations, saving $48.8 billion (societal perspective and starting treatment after 5% of the population has been exposed). Our study quantifies the potential effects of reducing the SARS-CoV-2 infectious period duration. 相似文献
2.
Coordinated eye-head movements evoked by the presentation of visual, auditory and combined audio-visual targets were studied in 24 human subjects. At 60 deg located targets latencies of eye and head movements were shorter for auditory than for visual stimuli. Latencies were shorter for bisensory than for monosensory targets. The eye and head latencies were differently influenced by the modality of the stimulus when the eccentricity of the target was changed, but not by the variation of the stimulus duration. The different responses of the eye and the head depending on target modality and target eccentricity can be partially attributed to perceptual and central processing mechanisms, and are important to answer the question about the initial event in coordinated eye-head orientation. 相似文献
3.
Lampert Winfried Fleckner Walter Pott Eckart Schober Ursula Störkel Karl-Ulrich 《Hydrobiologia》1989,(1):415-424
Bioassays of different complexity were compared with respect to their capability to predict the environmental impact of the herbicide atrazine in aquatic systems. Acute toxicity tests with Daphnia did not yield meaningful results. Sublethal tests with Daphnia (feeding inhibition, reduction of growth and reproduction) were more sensitive, but effective concentrations of atrazine were still rather high (2 mg/L). A relatively complicated artificial food chain system that incorporated direct and indirect effects on Daphnia yielded significant reduction of daphnid population growth at 0.1 mg/L. Enclosure experiments with natural communities were by far the most sensitive tools. Community responses could be measured at concentrations as low as 1 µg/L and 0.1 µg atrazine/L. At the lowest concentration, however, communities recovered after three weeks. We conclude that in complex systems indirect effects can be more important than direct effects, so that, contrary to the conditions in simple tests, non-target organisms may be the better indicators of herbicide stress to natural communities. 相似文献
4.
Amino acid sequence of Manduca sexta adipokinetic hormone elucidated by combined fast atom bombardment (FAB)/tandem mass spectrometry 总被引:1,自引:0,他引:1
R Ziegler K Eckart H Schwarz R Keller 《Biochemical and biophysical research communications》1985,133(1):337-342
Combination of Fast Atom Bombardment Tandem Mass Spectrometry with Amino Acid Analysis assigns the amino acid sequence of the Manduca sexta adipokinetic hormone as pGlu-Leu-Thr-Phe-Thr-Ser-Ser-Trp-GlyNH2. Similarities and differences with other invertebrate hormones and with mammalian glucagon are discussed. 相似文献
5.
Synthesis and phosphorylation of cytoskeleton components in foetal,regenerating and adult normal rat hepatocytes during culture 总被引:1,自引:0,他引:1
Georges Baffet Annie Ruelland Bruno Clement Elisabeth Le Rumeur Siegmund Fischer 《Molecular and cellular biochemistry》1985,68(2):97-105
Summary Detergent insoluble material (DIM) was prepared by gentle treatment with detergent from foetal, regenerating and adult normal rat hepatocytes cultured for various times. It retained to some degree the morphology of the cells. After incubation of intact cells with 35S-methionine, most of the labelled DIM proteins were found to be components of the cytoskeleton. They included several cytokeratins, vimentin and actin. The synthesis rate varied with the age of animals and culture conditions. The high synthetic rate of vimentin in foetal and regenerating hepatocytes could be associated with cell proliferation. No correlation was found between cytokeratin synthesis and hepatocyte growth. Most of the cytoskeleton proteins could be phosphorylated in intact cells and in DIM from cultured hepatocytes. However the degree of phosphorylation of these proteins was not related to their synthetic rate. The decreased phosphorylation level in cultured adult rat hepatocytes could be related to the rapid loss of specific functions. 相似文献
6.
Summary Analysis by gas chromatography revealed the presence of small amounts of squalene, but not lanosterol nor ergosterol in Pythium paroecandrum, P. ultimum, P. graminicola, and P. arrhenomonas. However, when acetate-14C was used as a precursor for sterols, even squalene was not found in P. graminicola. The deficiency in the sterol synthesizing mechanism may therefore be at or before the squalene forming step. Both squalene and ergosterol were present in the mycelium of Rhizoctonia solani, as shown by both gas chromatography and by the incorporation of acetate-14C into ergosterol. The absence of ergosterol in Pythium and its presence in Rhizoctonia is consistant with the resistance to the antibiotic filipin of Pythium species and the sensitivity of R. solani. 相似文献
7.
K Thielmann M Schulze H H Hoeppener G Hofmann S Siegmund 《Acta biologica et medica Germanica》1968,21(6):767-780
8.
Summary The growth of several Pythium species is increased between 65 and 100% if cholesterol is added to the growth medium. The optimum concentration is 15 mcg per ml. Mycelium of Pythium ultimum, in which cholesterol is present, incorporates glucose-U-14C and releases 14CO2 at a faster rate than the corresponding sterol free mycelium. In sterol containing cells, more 14CO2 is produced from a given amount of absorbed glucose-U-14C than in sterol free cells, there is thus in sterol containing hyphae a higher level of energy production. This condition can account for the increase in growth due to cholesterol. Only if sterols are present in the cellular membranes of Pythium species is the optimum synthetic capacity reached. 相似文献
9.
Yutaka Ishigami Yasuo Gama Yoh Sano Siegmund Lang Fritz Wagner 《Biotechnology letters》1994,16(6):593-598
Summary Glucose lipid of notable surfactant properties was produced by using hydrocarbon assimilating bacterium of the bacterial strain MM1. Its surface active properties were notable in spite of ,-hydrophilic and bulky molecule. The critical micelle concentration (cmc) was small (0.165 M); surface and interfacial tension for hexadecane at 0.1 % (pH 7.35) solution, 24.6 and 13.3 mN/m, respectively. The emulsifying action was excellent and comparable to those of rhamnolipids. The micelle has the outer radius. 28.5 Å and inner core, 6.7 Å on the basis of the concentric spherical shell model by means of the small angle X-ray solution scattering measurement.Dedicated to Professor Fritz Wagner on the occasion of his 65th birthday. 相似文献
10.
Matthias Kronen Helmar G?rls Hoai-Huong Nguyen Siegmund Reissmann Martin Bohl Jürgen Sühnel Udo Gr?fe 《Journal of peptide science》2003,9(11-12):729-744
Ampullosporin A is a 15-mer peptaibol type polypeptide that induces pigment formation by the fungus Phoma destructiva, forms voltage-dependent ion channels in membranes and exhibits hypothermic effects in mice. The structure of ampullosporin A has been determined by x-ray crystallography. This is the first three-dimensional (3D) structure of the peptaibol subfamily SF6. From the N-terminus to residue 13 the molecule adopts an approximate right-handed alpha-helical geometry, whereas a less regular structure pattern with beta-turn characteristics is found in the C-terminus. Even though ampullosporin A does not contain a single proline or hydroxyproline it is significantly bent. It belongs to both the shortest and the most strongly bent peptaibol 3D structures. The straight structure part encompasses residues Ac-Trp(1)-Aib(10) and is thus less extended than the alpha-helical subunit. The 3D structure of ampullosporin A is discussed in relation to other experimentally determined peptaibol structures and in the context of its channel-forming properties. As a part of this comparison a novel bending analysis based on a 3D curvilinear axis describing the global structural characteristics has been proposed and applied to all 3D peptaibol structures. A sampling of 2500 conformations using different molecular dynamics protocols yields, for the complete ampullosporin A structure, an alpha-helix as the preferred conformation in vacuo with almost no bend. This indicates that solvent or crystal effects may be important for the experimentally observed peptide backbone bending characteristics of ampullosporin A. 相似文献