ANALYSIS OF MUSCLE STRENGTH CHARACTERISTICS FOR FLEXION AND EXTENSION OF THE KNEE JOINT IN FEMALE CYCLING ATHLETES

The purpose of this study was to analyze the characteristics of muscle strength that is involved in extension and flexion of the knee joint in female cyclists. The flexion and extension exercise of the knee joint is the main source of the muscle power used by the bicycle athlete. It is also one of the subjects which attracts a great deal of attention from scientific researchers and instructors of physical culture both inside and outside of China. For the present study, an advanced CYBEX6000 dynamic testing equipment were used to carry out a considerable amount of research on athletes in various sports events. Based on the published studies from national and international, a specific theory, analysis and exploration were made to the working condition of muscle flexion and extension of the knee joint from the bicycle athlete. The following conclusion was gotten from the comparison between experienced athletes engaged in swimming and boat racing. It was found that athletes engaged in different sports, have different working characteristics of muscle strength from the knee joint. For the experienced bicycle athletes, with the acceleration of rotating speed of the knee joint, the descending degree of the maximum extension muscle torque is much greater than that of the flexion muscle

Expansion dynamics of Bose-Einstein condensates in a synthetic magnetic field

We investigate the expansion dynamics of spin-orbit-coupled Bose-Einstein condensates subjected to a synthetic magnetic field, after their release from an external harmonic trap. Our findings reveal that the condensate experiences a spin-dependent rotation and separation due to the rigid-like rotational velocity field, which leads to a spin density deflection. The deflection angle reaches a peak at a time that is inversely related to the frequency of the harmonic trap. When the detuning gradient is below a critical value for vortex nucleation, our analytical results derived from a spinor hydrodynamic theory align closely with numerical results using the coupled Gross-Pitaevskii equations. Beyond this critical value, we also numerically simulated the expansion dynamics of the condensates containing vortices with negative circulation. Our findings highlight the pivotal role of the rigid-like rotational velocity field on the dynamics of the condensate and may stimulate further experimental investigations into the rich superfluid dynamics induced by synthetic magnetic fields.Comment: 8 pages, 6 figure

CoMP Transmission in Downlink NOMA-Based Cellular-Connected UAV Networks

In this paper, we study the integration between the coordinated multipoint (CoMP) transmission and the non-orthogonal multiple access (NOMA) in the downlink cellular-connected UAV networks with the coexistence of aerial users (AUs) and terrestrial users (TUs). Based on the comparison of the desired signal strength to the dominant interference strength, the AUs are classified into CoMP-AUs and Non-CoMP AUs, where the former receives transmissions from two cooperative BSs, and constructs two exclusive NOMA clusters with two TUs, respectively. A Non-CoMP AU constructs a NOMA cluster with a TU served by the same BS. By leveraging the tools from stochastic geometry, we propose a novel analytical framework to evaluate the performance of the CoMP-NOMA based cellular-connected UAV network in terms of coverage probability, and average ergodic rate. We reveal the superiority of the proposed CoMP-NOMA scheme by comparing with three benchmark schemes, and further quantify the impacts of key system parameters on the network performance. By harvesting the benefits of both CoMP and NOMA, we prove that the proposed framework can provide reliable connection for AUs by using CoMP and enhance the average ergodic rate through NOMA technique as well.Comment: 29 pages,10 figures, submitted to a transaction journa

Apical conicity ratio: A new index on left ventricular apical geometry after myocardial infarction

ObjectiveOur objective was to introduce a new index to evaluate left ventricular aneurysm by quantitative analysis of left ventricular apical geometry.MethodsA total of 116 selected subjects underwent magnetic resonance imaging, 28 healthy volunteers, 29 patients with dilated cardiomyopathy, and 59 patients with ischemic heart disease (26 with left ventricular aneurysm; 33 with no aneurysm). The apical conicity ratio was calculated as the ratio of left ventricular apical area over apical triangle.ResultsDiastolic apical conicity ratio of patients with left ventricular aneurysm was 1.62 ± 0.20 and systolic apical conicity ratio was 1.78 ± 0.43. After left ventricular reconstruction, the diastolic apical conicity ratio decreased to 1.47 ± 0.23 and the systolic ratio to 1.51 ± 0.21, which came close to the normal level, whereas other global indices remained. In patients with dilated cardiomyopathy, sphericity index and eccentricity index increased significantly without changes in the apical conicity ratio. Among patients with ischemic heart disease, the apical conicity ratio of the group with left ventricular aneurysm was significantly higher than that of the group without an aneurysm when the other indices between the 2 groups showed no statistically difference. Receiver operating characteristic curves showed only apical conicity ratio had high power of discriminating left ventricular aneurysm from no aneurysm.ConclusionsThe new index, apical conicity ratio, can be used to quantify the regional left ventricular deformation, especially in patients with left ventricular aneurysm resulting from myocardial infarction

Knockout of the S-acyltransferase Gene, PbPAT14, Confers the Dwarf Yellowing Phenotype in First Generation Pear by ABA Accumulation.

The development of dwarf fruit trees with smaller and compact characteristics leads to significantly increased fruit production, which is a major objective of pear (Pyrus bretschneideri) breeding. We identified the S-acylation activity of PbPAT14, an S-acyltransferase gene related to plant development, using a yeast (Saccharomyces cerevisiae) complementation assay, and also PbPAT14 could rescue the growth defect of the Arabidopsis mutant atpat14. We further studied the function of PbPAT14 by designing three guide RNAs for PbPAT14 to use in the CRISPR/Cas9 system. We obtained 22 positive transgenic pear lines via Agrobacterium-mediated transformation using cotyledons from seeds of Pyrus betulifolia ('Duli'). Six of these lines exhibited the dwarf yellowing phenotype and were homozygous mutations according to sequencing analysis. Ultrastructure analysis suggested that this dwarfism was manifested by shorter, thinner stems due to a reduction in cell number. A higher level of endogenous abscisic acid (ABA) and a higher transcript level of the ABA pathway genes in the mutant lines revealed that the PbPAT14 function was related to the ABA pathway. Overall, our experimental results increase the understanding of how PATs function in plants and help elucidate the mechanism of plant dwarfism

Band Structure Engineering of Interfacial Semiconductors Based on Atomically Thin Lead Iodide Crystals

To explore new constituents in two-dimensional materials and to combine their best in van der Waals heterostructures, are in great demand as being unique platform to discover new physical phenomena and to design novel functionalities in interface-based devices. Herein, PbI2 crystals as thin as few-layers are first synthesized, particularly through a facile low-temperature solution approach with the crystals of large size, regular shape, different thicknesses and high-yields. As a prototypical demonstration of flexible band engineering of PbI2-based interfacial semiconductors, these PbI2 crystals are subsequently assembled with several transition metal dichalcogenide monolayers. The photoluminescence of MoS2 is strongly enhanced in MoS2/PbI2 stacks, while a dramatic photoluminescence quenching of WS2 and WSe2 is revealed in WS2/PbI2 and WSe2/PbI2 stacks. This is attributed to the effective heterojunction formation between PbI2 and these monolayers, but type I band alignment in MoS2/PbI2 stacks where fast-transferred charge carriers accumulate in MoS2 with high emission efficiency, and type II in WS2/PbI2 and WSe2/PbI2 stacks with separated electrons and holes suitable for light harvesting. Our results demonstrate that MoS2, WS2, WSe2 monolayers with very similar electronic structures themselves, show completely distinct light-matter interactions when interfacing with PbI2, providing unprecedent capabilities to engineer the device performance of two-dimensional heterostructures.Comment: 36 pages, 5 figure

Research on Quality and Flavor Characteristics of Five Kinds of Commercially Available Sour Fish Sauce in Qiandongnan

Five kinds of commercially available sour fish sauce were taken as the research object to clarify their quality and flavor characteristics. The physicochemical and nutritional indexes, free amino acids, and volatile components were analyzed. The results showed that the moisture, ash, total acid, amino acid nitrogen, reducing sugar, protein, vitamin C and fat contents in the five kinds of sour fish sauce were significantly different (P<0.05). In total, 17 free amino acids were detected, including 7 essential amino acids and 10 non-essential amino acids. The content of total free amino acids in the samples ranged from 7.954~14.998 mg/g. The total content of free amino acids in sample Z was the highest at 14.998 mg/g. The content of umami glutamic acid was the highest in the L sample, which was 4.689 mg/g, and the taste activity value (TAV) reached 15.63, which was much higher than that of other samples. The electronic nose results showed that the main volatile components of five kinds of sour fish sauce were nitrogen oxides, short-chain alkanes, inorganic sulfur compounds, alcohol ether aldehydes, and organic sulfides. Principal component analysis could differentiate between different sour fish sauces. In this study, 57 volatile components were detected in five kinds of sour fish sauce using gas chromatography-mass spectrometry (GC-MS), including 20 esters, 14 alcohols, 14 alkenes, 2 acids, 2 phenols, 3 aldehydes and 2 ketones. Using orthogonal least squares-discriminant analysis (OPLS-DA) and variable important projection (VIP) selection, eighteen key volatile aroma compounds, including zingalene, ethanol, ethyl cetanoate, ethyl linoleate, limonene, acetic acid, linalool, ethyl myristate, 4-ethyl-2-methoxyphenol, phenethyl alcohol, alpha-curcumene, methyl salicylate, β-sesquiphellandrene, citral, isoamyl alcohol, camphene, β-bisabolene and geraniol, were identified in the five kinds of sour fish sauce. In conclusion, the results provide a basis for the quality evaluation and comprehensive development of sour fish sauce