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991.
992.
Inverse dynamics based simulations on musculoskeletal models is a commonly used method for the analysis of human movement. Due to inaccuracies in the kinematic and force plate data, and a mismatch between the model and the subject, the equations of motion are violated when solving the inverse dynamics problem. As a result, dynamic inconsistency will exist and lead to residual forces and moments. In this study, we present and evaluate a computational method to perform inverse dynamics-based simulations without force plates, which both improves the dynamic consistency as well as removes the model?s dependency on measured external forces. Using the equations of motion and a scaled musculoskeletal model, the ground reaction forces and moments (GRF&Ms) are derived from three-dimensional full-body motion. The method entails a dynamic contact model and optimization techniques to solve the indeterminacy problem during a double contact phase and, in contrast to previously proposed techniques, does not require training or empirical data. The method was applied to nine healthy subjects performing several Activities of Daily Living (ADLs) and evaluated with simultaneously measured force plate data. Except for the transverse ground reaction moment, no significant differences (P>0.05) were found between the mean predicted and measured GRF&Ms for almost all ADLs. The mean residual forces and moments, however, were significantly reduced (P>0.05) in almost all ADLs using our method compared to conventional inverse dynamic simulations. Hence, the proposed method may be used instead of raw force plate data in human movement analysis using inverse dynamics. 相似文献
993.
Stephen H Gregory Leslie P Cousens Nico van Rooijen Ed A D?pp Timothy M Carlos Edward J Wing 《Journal of immunology (Baltimore, Md. : 1950)》2002,168(1):308-315
Most bacteria that enter the bloodstream are taken up by the liver. Previously, we reported that such organisms are initially bound extracellularly and subsequently killed by immigrating neutrophils, not Kupffer cells as widely presumed in the literature. Rather, the principal functions of Kupffer cells demonstrated herein are to clear bacteria from the peripheral blood and to promote accumulation of bactericidal neutrophils at the principal site of microbial deposition in the liver, i.e., the Kupffer cell surface. In a mouse model of listeriosis, uptake of bacteria by the liver at 10 min postinfection i.v. was reduced from approximately 60% of the inoculum in normal mice to approximately 15% in mice rendered Kupffer cell deficient. Immunocytochemical analysis of liver sections derived from normal animals at 2 h postinfection revealed the massive immigration of neutrophils and their colocalization with Kupffer cells. Photomicrographs of the purified nonparenchymal liver cell population derived from these infected mice demonstrated listeriae inside neutrophils and neutrophils within Kupffer cells. Complementary adhesion molecules promoted the interaction between these two cell populations. Pretreatment of mice with mAbs specific for CD11b/CD18 (type 3 complement receptor) or its counter-receptor, CD54, inhibited the accumulation of neutrophils in the liver and the elimination of listeriae. Complement was not a factor; complement depletion affected neither the clearance of listeriae by Kupffer cells nor the antimicrobial activity expressed by infiltrating neutrophils. 相似文献
994.
Joerg Seidler Nico Zinn Erik Haaf Martin E. Boehm Dominic Winter Andreas Schlosser Wolf D. Lehmann 《Amino acids》2011,41(2):311-320
It is hypothesized that metal ion-mediated adsorption of phosphorylated peptides on stationary phases of LC-columns is the
major cause for their frequently observed poor detection efficiency in LC-MS. To study this phenomenon in more detail, sample
solutions spiked with metal ion-mobilizing additives were analyzed by reversed phase μLC-ICP-MS or nanoLC-ESI-MS. Using μLC-ICP-MS,
metal ions were analyzed directly as atomic ions. Using electrospray ionization, either metal ion chelates or phosphopeptide
standard mixtures injected in subpicomole amounts were analyzed. Deferoxamine, imidazole, ascorbate, citrate, EDTA, and the
tetrapeptide pSpSpSpS were tested as sample additives for the interlinked purposes of metal ion-mobilization and improvement
of phosphopeptide recovery. Iron probably represents the major metal ion contamination of reversed phase columns. Based on
the certified iron level in LC-grade solvents, a daily metal ion load of >10 pmol was estimated for typical nanoLC flow rates.
In addition, phosphopeptide fractions from IMAC columns were identified as source for metal ion contamination of the LC column,
as demonstrated for Ga3+-IMAC. The three metal ion-chelating additives, EDTA, citrate and pSpSpSpS, were found to perform best for improving the LC
recovery of multiply phosphorylated peptides injected at subpicomole amounts. The benefits of metal ion-mobilizing LC (mimLC)
characterized by metal ion complexing sample additives is demonstrated for three different instrumental setups comprising
(a) a nanoUPLC-system with direct injection on the analytical column, (b) a nanoLC system with inclusion of a trapping column,
and (c) the use of a HPLC-Chip system with integrated trapping and analytical column. 相似文献
995.
996.
Blomme B Van Steenkiste C Grassi P Haslam SM Dell A Callewaert N Van Vlierberghe H 《American journal of physiology. Gastrointestinal and liver physiology》2011,300(5):G833-G842
N-glycosylation of immunoglobulin G (IgG) has an important impact on the modification of the total serum N-glycome in chronic liver patients. Our aim was to determine the role and magnitude of the alterations in which hepatocytes and B cells are involved in two mouse models of chronic liver disease. Common bile duct ligation (CBDL) and subcutaneous injections with CCl(4) were induced in B cell-deficient and wild-type (WT) mice. IgG depletion was performed with beads covered with protein A/G and the depletions were evaluated by SDS-PAGE and Western blot analysis. N-glycan analysis was performed by improved DSA-FACE technology. Structural analysis of the mouse serum N-glycans was performed by exoglycosidase digests and MALDI-TOF mass spectrometry of permethylated glycans. The alterations seen in B cell-deficient mice closely resembled the alterations in WT mice, in both the CBDL and the CCl(4) models. N-glycan analysis of the IgG fraction in both mouse models revealed different changes compared with humans. Overall, the impact of IgG glycosylation on total serum glycosylation was marginal. Interestingly, the amount of fibrosis present in CBDL B cell-deficient mice was significantly increased compared with CBDL WT mice, whereas the opposite was true for the CCl(4) model as determined by Sirius red staining. However, this had no major effect on the alteration of N-glycosylation of serum proteins. Alterations of total serum N-glycome in mouse models of chronic liver disease are hepatocyte-driven. Undergalactosylation of IgG is not present in mouse models of chronic liver disease. 相似文献
997.
In the twenty-first century, scientists will want to steer the microbial black box in (engineered) ecosystems, rather than
only study and describe them. This strategy led to a new way of thinking: Microbial Resource Management (MRM). For the last
few years, MRM has been utilized to consolidate and communicate our acquired knowledge of the microbiome to many areas of
the scientific community. This shared knowledge has brought us closer to formulating a plan toward the analysis, and at a
later stage, the management of our varied microbial communities and to look at ways of harnessing their unique abilities for
future practices. We require this acquired knowledge for a more sustainable solution to our ongoing global challenges such
as our diminishing energy and water supply. Like any successful concept, MRM must be updated to adapt to new molecular technologies,
and thus, in this review, MRM has been reengineered to encompass these changes. This review reports how MRM has been used
successfully over the last few years within various environments and how we can broaden its capabilities to increase its compliance
in the face of state of the art ever changing technologies. Not only have we reengineered and improved MRM, but also we have
discussed how newly formed relationships between technologies can provide the full picture of these complex microbial communities
and their interactions for future opportunities. 相似文献
998.
Skin temperature shows spontaneous ultradian fluctuations during everyday-life wakefulness. Previous work showed that mild manipulations of skin temperature affect human sleep and vigilance, presumably by influencing neuronal systems involved in both thermal sensing and arousal regulation. We therefore examined whether fluctuations in skin temperature are associated with those in vigilance level under conditions similar to everyday-life situations requiring sustained attention. Eight healthy participants (30.1 ± 8.1 years, M ± SD) participated in a 2-day protocol, during which vigilance and skin temperature were assessed 4 times per day in a silent, dimly lit, temperature-controlled room. Vigilance was assessed by measuring reaction speed and lapses on a novel sustained vigilance task specifically designed to increase lapse rate and range of reaction times. Skin temperature was sampled at 30-second intervals from 3 locations: distal, intermediate, and proximal temperatures were obtained from the middle finger (T(finger) ), the wrist (T(wrist)), and the infraclavicular area (T(chest)), respectively. Furthermore, 3 distal to proximal gradients were calculated. Mixed-effect regression analyses were used to evaluate the association of the fluctuations in temperatures and gradients and those in response speed and lapse probability. Especially the spontaneous fluctuations in proximal temperature were negatively associated with fluctuations in response speed and positively with lapse rate. If individual T(chest) temperature ranges were classified into 10 deciles, they accounted for 23% of the variance in response speed and 11% of the variance in lapse rate. The findings indicate coupling between the spontaneous fluctuations in skin temperature and vigilance during the day and are compatible with the hypothesis of overlap in brain networks involved in the regulation of temperature and vigilance. From an applied point of view, especially proximal skin temperature assessment may be of use in vigilance monitoring. 相似文献
999.
Animal models with high predictive power are a prerequisite for translational research. The closer the similarity of a model to Parkinson??s disease (PD), the higher is the predictive value for clinical trials. An ideal PD model should present behavioral signs and pathology that resemble the human disease. The increasing understanding of PD stratification and etiology, however, complicates the choice of adequate animal models for preclinical studies. An ultimate mouse model, relevant to address all PD-related questions, is yet to be developed. However, many of the existing models are useful in answering specific questions. An appropriate model should be chosen after considering both the context of the research and the model properties. This review addresses the validity, strengths, and limitations of current PD mouse models for translational research. 相似文献
1000.
CD2 associated protein (CD2AP) is an adaptor protein that plays an important role in cell to cell union needed for the kidney
function. It contains three N-terminal SH3 domains that are able to interact among others with CD2, ALIX, c-Cbl and Ubiquitin.
To understand the role of the individual SH3 domains of this adaptor protein we have performed a complete structural, thermodynamic
and dynamic characterization of the separate domains using NMR and DSC. The energetic contributions to the stability and the
backbone dynamics have been related to the structural features of each domain using the structure-based FoldX algorithm. We
have found that the N-terminal SH3 domain of both adaptor proteins CD2AP and CIN85 are the most stable SH3 domains that have
been studied until now. This high stability is driven by a more extensive network of intra-molecular interactions. We believe
that this increased stabilization of N-terminal SH3 domains in adaptor proteins is crucial to maintain the necessary conformation
to establish the proper interactions critical for the recruitment of their natural targets. 相似文献