THE EFFECT OF PASSIVE AND ACTIVE IMPULSE ON THE PERFORMANCES OF DROP JUMPS

This experiment is to investigate the ground reaction forces of lhree diHerent heights of drop-jumps (DJ) in order to understand the eHect of passive and active impulses on the performance of DJ. Eleven subjects were asked to perform DJs. AMIT force-platform and penny electrical gonia-meter were used to record the ground reaction forces and knee angular displacement. After treating the data and discussion, the conclusions were obtained. The active force as well as the active impulse are that of DJ20=DJ40=DJ60 whose result is consistent with the flight-height of these three diHerent DJ. On the other hand, the higher the jump-altitude is, the larger the passive impulse and passive force are. This result is very diHerent from that of flight-height, so the passive impulsive seems to have no help to prompt the performances of DJs. After further examination of the ground reaction force, we found that the key determinant process is the PARFD that slopes down as the jump-heights increase. The DJ60 induces the largest passive impulse but also accompanies negative PARFD. On other hand, the DJ20 induces the smallest passive impulse but accompanies positive PARFD. Finally, the performances of DJ20, DJ40 and DJ60 have no diHerence

THE REGULATION OF LEG STIFFNESS AND EMG ACTIVITIES ON PERSON WITH VISUAL IMPAIRED DURING STEP-DOWN WALKING

The purpose of present study was to evaluate leg muscular regulation and neuromuscular activation by investigating the stiffness and EMG amplitude of normal vision students and visually impaired students. 10 normal vision (age: 24.3±20 years; height: 171.5±4.6cm; mass: 65.9±8.0kg) and 10 visually impaired students (age: 23.2±2.4 years; height: 163.4±9.6cm; mass: 62.8±15.0kg) were served as subjects. AMTI force platform (1200 Hz), Peak Performance motion analysis system (60Hz) and Biovision EMG system were used synchronously to record the ground reaction force, the kinematic parameters and EMG signals of lower extremity during the subjects stepped down from height 20, 30 and 40cm. The results revealed that the regulation of neuromuscular system of the impaired is less efficient compared to the normal one because of lower muscle stiffness and EMG activity

Biomechanical Characteristics and EMG Activities of Weighted Countermovement Jump

The purpose of this study was to investigate the biomechanical characteristics and EMG activities during a weighted countermovement jump (WCMJ) with 0%, 25% and 50% of body weight. Eight male college students participated this study. An AMTI force platform, Penny&Giles goniometer and Biovision EMG system were used synchronously to record the related parameters while subjects performed WCMJs. The results indicate that by increasing load, the eccentric mean force, the maximum force and concentric impulse increases significantly. With the load increase, the EMG activities of soleus and gastrocnemius did not changed significantly, while the eccentric mean EMG amplitude of rectus femoris got greater. This reveals that WCMJ has a marked influence on the lower extremity, especially on the rectus femoris

Plasmonic Circular Nanostructure for Enhanced Light Absorption in Organic Solar Cells

This study attempts to enhance broadband absorption in advanced plasmonic circular nanostructures (PCN). Experimental results indicate that the concentric circular metallic gratings can enhance broadband optical absorption, due to the structure geometry and the excitation of surface plasmon mode. The interaction between plasmonic enhancement and the absorption characteristics of the organic materials (P3HT:PCBM and PEDOT:PSS) are also examined. According to those results, the organic material's overall optical absorption can be significantly enhanced by up to ~51% over that of a planar device. Additionally, organic materials are enhanced to a maximum of 65% for PCN grating pitch = 800 nm. As a result of the PCN's enhancement in optical absorption, incorporation of the PCN into P3HT:PCBM-based organic solar cells (OSCs) significantly improved the performance of the solar cells: short-circuit current increased from 10.125 to 12.249 and power conversion efficiency from 3.2% to 4.99%. Furthermore, optimizing the OSCs architectures further improves the performance of the absorption and PCE enhancement

Risk factors for Kaposi's sarcoma in human immunodeficiency virus patients after initiation of antiretroviral therapy: A nested case–control study in Kenya

AbstractBackground/PurposeThis study aimed to evaluate the association between highly active antiretroviral therapy (HAART) adherence and development of Kaposi's sarcoma (KS) in human immunodeficiency virus (HIV)/AIDS patients.MethodsWe conducted a retrospective nested case–control study of 165 participants (33 cases and 132 controls) receiving HAART care at Maseno Hospital, Kenya, from January 2005 to October 2013. Cases were HIV-positive adults with KS, who were matched with controls in a ratio of 1:4 based on age (±5 years of each case), sex, and KS diagnosis date. Perfect adherence to HAART was assessed on every clinic visit by patients' self-reporting and pill counts. Chi-square tests were performed to compare socioeconomic and clinical statuses between cases and controls. A conditional logistic regression was used to assess the effects of perfect adherence to HAART, the latest CD4 count, education level, distance to health-care facility, initial World Health Organization stage, and number of regular sexual partners on the development of KS.ResultsOnly 63.6% participants reported perfect adherence, and the control group had a significantly higher percentage of perfect adherence (75.0%) than did cases (18.2%). After adjustment for potential imbalances in the baseline and clinical characteristics, patients with imperfect HAART adherence had 20-times greater risk of developing KS than patients with perfect HAART adherence [hazard ratios: 21.0, 95% confidence interval: 4.2–105.1]. Patients with low latest CD4 count (≤350 cells/mm3) had a seven-times greater risk of developing KS than did their counterparts (HRs: 7.1, 95% CI: 1.4–36.2).ConclusionImperfect HAART adherence and low latest CD4 count are significantly associated with KS development

The Design and Analysis of Passive Pitch Control for Horizontal Axis Wind Turbine

AbstractThe purpose of this thesis is to design and analysis of passive pitch control. Design a mechanics to control different revolution of blade's pitch angle. The use of small wind turbines gradually popularization, but how to overcome the low wind speed start-up and the operation under high wind speed, that is the difficult problems encountered by designers. In order to extend the use and the safe of wind speed, this design is required. This paper is focus on the mechanism design of the passive pitch control for the small horizontal axis wind turbine (HAWT). When the wind speed is fast, the rotation speed is also faster and faster. The system uses centrifugal force to make Pulley disk driven the pitch angle of the blade. It can achieve the effect of passive pitch control. The mechanism is our laboratory's patent. Through the experiments in wind tunnel, it can be observed the variation of the performance curve when the pitch rotation. This system not only successfully operates under high wind speed but also has better performance at low wind speed

Identification and subcellular localization of a novel Cu,Zn superoxide dismutase of Mycobacterium tuberculosis

AbstractPeriplasmic copper, zinc superoxide dismutases (Cu,ZnSOD) of several Gram-negative pathogens have been shown to play an important role in protection against exogenous superoxide radicals and in determining virulence of the pathogens. Here we report the cloning and characterization of the sodC gene, encoding Cu,ZnSOD, from the Gram-positive Mycobacterium tuberculosis. The predicted protein sequence contains 240 amino acids with a putative signal peptide at the N-terminus and shows ∼25% identity to other bacterial sodC. Recombinant proteins of a full-length sodC and a truncated form lacking the putative signal peptide were overexpressed in Escherichia coli and affinity purified. Renatured recombinant M. tuberculosis sodC protein possessed characteristics of a Cu,ZnSOD. Immunoblotting with an antiserum against the recombinant M. tuberculosis Cu,ZnSOD allowed detection of a single polypeptide in the lysate of M. tuberculosis. This polypeptide has a similar size as the recombinant protein without the putative signal peptide indicating that the endogenous Cu,ZnSOD in M. tuberculosis might be processed and secreted. Furthermore, immunogold electron microscopic image showed that Cu,ZnSOD is located in the periphery of M. tuberculosis. The enzymatic activity and subcellular localization of this novel Cu,ZnSOD suggest that it may play a role in determining virulence of M. tuberculosis

Genomic diversity of citrate fermentation in Klebsiella pneumoniae

<p>Abstract</p> <p>Background</p> <p>It has long been recognized that <it>Klebsiella pneumoniae </it>can grow anaerobically on citrate. Genes responsible for citrate fermentation of <it>K. pneumoniae </it>were known to be located in a 13-kb gene cluster on the chromosome. By whole genome comparison of the available <it>K. pneumoniae </it>sequences (MGH 78578, 342, and NTUH-K2044), however, we discovered that the fermentation gene cluster was present in MGH 78578 and 342, but absent in NTUH-K2044. In the present study, the previously unknown genome diversity of citrate fermentation among <it>K. pneumoniae </it>clinical isolates was investigated.</p> <p>Results</p> <p>Using a genomic microarray containing probe sequences from multiple <it>K. pneumoniae </it>strains, we investigated genetic diversity among <it>K. pneumoniae </it>clinical isolates and found that a genomic region containing the citrate fermentation genes was not universally present in all strains. We confirmed by PCR analysis that the gene cluster was detectable in about half of the strains tested. To demonstrate the metabolic function of the genomic region, anaerobic growth of <it>K. pneumoniae </it>in artificial urine medium (AUM) was examined for ten strains with different clinical histories and genomic backgrounds, and the citrate fermentation potential was found correlated with the genomic region. PCR detection of the genomic region yielded high positive rates among a variety of clinical isolates collected from urine, blood, wound infection, and pneumonia. Conserved genetic organizations in the vicinity of the citrate fermentation gene clusters among <it>K. pneumoniae</it>, <it>Salmonella enterica</it>, and <it>Escherichia coli </it>suggest that the13-kb genomic region were not independently acquired.</p> <p>Conclusion</p> <p>Not all, but nearly half of the <it>K. pneumoniae </it>clinical isolates carry the genes responsible for anaerobic growth on citrate. Genomic variation of citrate fermentation genes in <it>K. pneumoniae </it>may contribute to metabolic diversity and adaptation to variable nutrient conditions in different environments.</p

A powerful and efficient multivariate approach for voxel-level connectome-wide association studies

We describe an approach to multivariate analysis, termed structured kernel principal component regression (sKPCR), to identify associations in voxel-level connectomes using resting-state functional magnetic resonance imaging (rsfMRI) data. This powerful and computationally efficient multivariate method can identify voxel-phenotype associations based on the whole-brain connectivity pattern of voxels, and it can detect linear and non-linear signals in both volume-based and surface-based rsfMRI data. For each voxel, sKPCR first extracts low-dimensional signals from the spatially smoothed connectivities by structured kernel principal component analysis, and then tests the voxel-phenotype associations by an adaptive regression model. The method's power is derived from appropriately modelling the spatial structure of the data when performing dimension reduction, and then adaptively choosing an optimal dimension for association testing using the adaptive regression strategy. Simulations based on real connectome data have shown that sKPCR can accurately control the false-positive rate and that it is more powerful than many state-of-the-art approaches, such as the connectivity-wise generalized linear model (GLM) approach, multivariate distance matrix regression (MDMR), adaptive sum of powered score (aSPU) test, and least-square kernel machine (LSKM). Moreover, since sKPCR can reduce the computational cost of non-parametric permutation tests, its computation speed is much faster. To demonstrate the utility of sKPCR for real data analysis, we have also compared sKPCR with the above methods based on the identification of voxel-wise differences between schizophrenic patients and healthy controls in four independent rsfMRI datasets. The results showed that sKPCR had better between-sites reproducibility and a larger proportion of overlap with existing schizophrenia meta-analysis findings. Code for our approach can be downloaded from https://github.com/weikanggong/sKPCR. [Abstract copyright: Copyright © 2018 Elsevier Inc. All rights reserved.