排序方式: 共有43条查询结果,搜索用时 15 毫秒
1.
Jordan A. Cannon Pavlo A. Krokhmal Russell V. Lenth Robert Murphey 《Biomedical signal processing and control》2010,5(3):229-236
We consider the problem of on-the-fly detection of temporal changes in the cognitive state of human subjects due to varying levels of difficulty of performed tasks using real-time EEG and EOG data. We construct the Cognitive State Indicator (CSI) as a function that projects the multidimensional EEG/EOG signals onto the interval [0,1] by maximizing the Kullback–Leibler distance between distributions of the signals, and whose values change continuously with variations in cognitive load. During offline testing (i.e., when evolution in time is disregarded) it was demonstrated that the CSI can serve as a statistically significant discriminator between states of different cognitive loads. In the online setting, a trend detection heuristic (TDH) has been proposed to detect real-time changes in the cognitive state by monitoring trends in the CSI. Our results support the application of the CSI and the TDH in future closed-loop control systems with human supervision. 相似文献
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Saribaş AS Mobasseri A Pristatsky P Chen X Barthelson R Hakes D Wang J 《Glycobiology》2004,14(12):1217-1228
Heparan sulfate/heparin N-deacetylase/N-sulfotransferase-1 (NDST-1) is a critical enzyme involved in heparan sulfate/heparin biosynthesis. This dual-function enzyme modifies the GlcNAc-GlcA disaccharide repeating sugar backbone to make N-sulfated heparosan. N-sulfation is an absolute requirement for the subsequent epimerization and O-sulfation steps in heparan sulfate/heparin biosynthesis. We have expressed rat liver (r) NDST-1 in Saccharomyces cerevisiae as a soluble protein. The yeast-expressed enzyme has both N-deacetylase and N-sulfotransferase activities. N-acetyl heparosan, isolated from Escherichia coli K5 polysaccharide, de-N-sulfated heparin (DNSH) and completely desulfated N-acetylated heparan sulfate (CDSNAcHS) are all good substrates for the rNDST-1. However, N-desulfated, N-acetylated heparin (NDSNAcH) is a poor substrate. The rNDST-1 was partially purified on heparin Sepharose CL-6B. Purified rNDST-1 requires Mn(2+) for its enzymatic activity, can utilize PAPS regenerated in vitro by the PAPS cycle (PAP plus para-nitrophenylsulfate in the presence of arylsulfotransferase IV), and with the addition of exogenous PAPS is capable of producing 60-65% N-sulfated heparosan from E. coli K5 polysaccharide or Pasteurella multocida polysaccharide. 相似文献
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Ardanov Pavlo Ovcharenko Leonid Zaets Iryna Kozyrovska Natalia Pirttilä Anna Maria 《Biological Control》2011,56(1):43-49
Priming plants by non-pathogenic bacteria allows the host to save energy and to reduce time needed for development of defense reaction during a pathogen attack. However, information on the role of endophytes in plant defense is limited. Here, the ability of endophytic bacteria to promote growth and resistance of potato plants towards infection by the necrotroph Pectobacterium atrosepticum was studied. A Pseudomonas sp. strain was selected due to antagonism towards bacterial pathogens and a Methylobacterium sp. strain because of efficient plant colonization. The aim of this study was to find if there is any correlation between plant growth promotion and induction of resistance by endophytes of potato, as well as to study the putative mechanisms of endophytes interacting with the plant during resistance induction. Both tested strains promoted growth of potato shoots but only the Pseudomonas sp. increased potato resistance towards the soft rot disease. Induction of disease resistance by the Methylobacterium sp. was inversely proportional to the size of bacterial population used for inoculation. The plant antioxidant system was moderately activated during the induction of resistance by the biocontrol strains. qPCR data on expression of marker genes of induced systemic resistance and acquired systemic resistance in endophyte-infected Arabidopsis plants showed activation of both salicylic acid and jasmonate/ethylene-dependent pathways after challenge inoculation with the pathogen. We suggest that some endophytes have the potential to activate both basal and inducible plant defense systems, whereas the growth promotion by biocontrol strains may not correlate with induction of disease resistance. 相似文献
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Michelle T. Burstein Pavlo Kyryakov Adam Beach Vincent R. Richard Olivia Koupaki Alejandra Gomez-Perez Anna Leonov Sean Levy Forough Noohi Vladimir I. Titorenko 《Cell cycle (Georgetown, Tex.)》2012,11(18):3443-3462
Our studies revealed that LCA (lithocholic bile acid) extends yeast chronological lifespan if added to growth medium at the time of cell inoculation. We also demonstrated that longevity in chronologically aging yeast is programmed by the level of metabolic capacity and organelle organization that they developed before entering a quiescent state and, thus, that chronological aging in yeast is likely to be the final step of a developmental program progressing through at least one checkpoint prior to entry into quiescence. Here, we investigate how LCA influences longevity and several longevity-defining cellular processes in chronologically aging yeast if added to growth medium at different periods of the lifespan. We found that LCA can extend longevity of yeast under CR (caloric restriction) conditions only if added at either of two lifespan periods. One of them includes logarithmic and diauxic growth phases, whereas the other period exists in early stationary phase. Our findings suggest a mechanism linking the ability of LCA to increase the lifespan of CR yeast only if added at either of the two periods to its differential effects on various longevity-defining processes. In this mechanism, LCA controls these processes at three checkpoints that exist in logarithmic/diauxic, post-diauxic and early stationary phases. We therefore hypothesize that a biomolecular longevity network progresses through a series of checkpoints, at each of which (1) genetic, dietary and pharmacological anti-aging interventions modulate a distinct set of longevity-defining processes comprising the network; and (2) checkpoint-specific master regulators monitor and govern the functional states of these processes. 相似文献
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Ali Bakr Joschka Hey Gianluca Sigismondo Chun-Shan Liu Ahmed Sadik Ashish Goyal Alice Cross Ramya Lakshmana Iyer Patrick Müller Max Trauernicht Kersten Breuer Pavlo Lutsik Christiane
A Opitz Jeroen Krijgsveld Dieter Weichenhan Christoph Plass Odilia Popanda Peter Schmezer 《Nucleic acids research》2021,49(20):11666
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An analytical expression for the drying time of thin lumber is derived, based on a method presented in this study. The laws of moisture content change in wood as function of mass transfer are used for the theoretical approach. The diffusion equation for moisture content is set up for a three-dimensional block of lumber based on the assumption of uniform initial distribution of moisture throughout the specimen. The boundary condition stipulates that the moisture gradient at the boundary is proportional to the deviation of the moisture content of the slab from the equilibrium value at that temperature. These conditions are used to derive an analytical expression for the time required to get from an initial moisture distribution to a desired final moisture content of thin lumber. For a sample calculation, the result of drying time agrees within 10% with the prediction of previously published analytical formulas for the drying curve. 相似文献
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Sherry C. Wen Sharon J. Tollefson Monika Johnson Pavlo Gilchuk Kelli L. Boyd Bryan Shepherd Sebastian Joyce John V. Williams 《Journal of virology》2014,88(18):10963-10969
Human metapneumovirus (HMPV) is a major cause of respiratory disease. The role of NK cells in protection against HMPV is unclear. We show that while HMPV-infected C57BL/6 mice had higher numbers of functional lung NK cells than mock-treated mice, comparing NK cell-depleted and control mice did not reveal differences in lung viral titers, histopathology, cytokine levels, or T cell numbers or function. These data indicate that NK cells are not required for host control of HMPV. 相似文献
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Clara T. Schoeder Pavlo Gilchuk Amandeep K. Sangha Kaitlyn V. Ledwitch Delphine C. Malherbe Xuan Zhang Elad Binshtein Lauren E. Williamson Cristina E. Martina Jinhui Dong Erica Armstrong Rachel Sutton Rachel Nargi Jessica Rodriguez Natalia Kuzmina Brooke Fiala Neil P. King Alexander Bukreyev James E. Crowe Jr. Jens Meiler 《PLoS pathogens》2022,18(5)
The three human pathogenic ebolaviruses: Zaire (EBOV), Bundibugyo (BDBV), and Sudan (SUDV) virus, cause severe disease with high fatality rates. Epitopes of ebolavirus glycoprotein (GP) recognized by antibodies with binding breadth for all three ebolaviruses are of major interest for rational vaccine design. In particular, the heptad repeat 2 –membrane-proximal external region (HR2-MPER) epitope is relatively conserved between EBOV, BDBV, and SUDV GP and targeted by human broadly-neutralizing antibodies. To study whether this epitope can serve as an immunogen for the elicitation of broadly-reactive antibody responses, protein design in Rosetta was employed to transplant the HR2-MPER epitope identified from a co-crystal structure with the known broadly-reactive monoclonal antibody (mAb) BDBV223 onto smaller scaffold proteins. From computational analysis, selected immunogen designs were produced as recombinant proteins and functionally validated, leading to the identification of a sterile alpha motif (SAM) domain displaying the BDBV-HR2-MPER epitope near its C terminus as a promising candidate. The immunogen was fused to one component of a self-assembling, two-component nanoparticle and tested for immunogenicity in rabbits. Robust titers of cross-reactive serum antibodies to BDBV and EBOV GPs and moderate titers to SUDV GP were induced following immunization. To confirm the structural composition of the immunogens, solution NMR studies were conducted and revealed structural flexibility in the C-terminal residues of the epitope. Overall, our study represents the first report on an epitope-focused immunogen design based on the structurally challenging BDBV-HR2-MPER epitope. 相似文献
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Maksimov P Zerweck J Maksimov A Hotop A Gross U Spekker K Däubener W Werdermann S Niederstrasser O Petri E Mertens M Ulrich RG Conraths FJ Schares G 《PloS one》2012,7(3):e34212