Research progress on three-dimensional evaluation methods for facial asymmetry / 口腔疾病防治

@#Facial symmetry evaluation has always been a hot topic of concern for doctors who engage in the study of facial beauty disciplines such as orthodontics, dentistry, and plastic surgery. Although scholars at home and abroad have carried out much research on the evaluation of facial symmetry with a variety of emerging technologies and methods, there is still a lack of unified standards for the evaluation of facial asymmetry due to the complexity of the content and methods and individual subjectivity. Facial asymmetry involves changes in the length, width and height of the face. It is a complex dental and maxillofacial malformation whose early identification and accurate evaluation are particularly important. Clinically, in addition to the necessary dental and maxillofacial examinations, it is also necessary to evaluate facial asymmetry with the help of corresponding auxiliary methods. This paper gives a summary of the commonly used three-dimensional evaluation methods. The evaluation methods of facial asymmetry can be divided into 5 categories: qualitative analysis, quantitative analysis, dynamic analysis, mathematical analysis, and artificial intelligence analysis. After the analysis and summarization of the characteristics, advantages and limitations of each method in clinical applications, it is found that although these methods vary in accuracy, evaluation scope, diagnosis nature and calculation method, etc., the three-dimensional evaluation methods are more objective, more accurate and more convenient and will become the mainstream evaluation method for facial asymmetry with further development of three-dimensional measurement technologies.

Assessment of apical pressures at different automated irrigant flow rates: an ex vivo study based on computational fluid dynamic analysis / Avaliação de pressões apicais em diferentes taxas de fluxo irrigante automatizadas: um estudo ex vivo baseado em análise dinâmica de fluidos computacionais

Objective: The current study aimed at assessing the induced apical pressure at various simulated irrigant flow rates. Materials and Methods: Forty eight freshly extracted single-rooted premolars were decoronated and prepared to size 30 0.04 taper using HY-Flex CM rotary file system and were scanned using cone-beam computed tomography (CBCT). The scanned images were reconstructed to three-dimensional Computer-aided design models (CAD) and the 3D needle was also reconstructed. Finally, simulations were done by placing the 30 gauge open-ended needle 3 mm short of the working length. Results: There was a statistically significant difference (p<0.05) among the different groups compared. 1 ml/min flow rate induced the least apical pressures (p<0.05) as compared to the other types. Conclusion: 1 ml/min flow rates induced the least apical pressures when open-ended needles are used for irrigation.(AU)

Objetivo: O presente estudo teve como objetivo avaliar a indução de pressão apical em várias taxas de fluxo irrigante simuladas. Material e Métodos: Quarenta e oito raízes de pré-molares unirradiculares recém extraídos tiveram suas coroas removidas, foram preparados para uma conicidade de tamanho 30 0.04 através de um sistema rotatório de limas HYFlex CM e foram escaneados via tomografia computadorizada cone-beam (CBCT). As imagens escaneadas e as agulhas para irrigação foram reconstruídas em modelos tridimensionais de design assistido por computador (CAD). Ao final, foram feitas simulações através de agulhas de calibre 30 e 3 mm a menos que o comprimento de trabalho. Resultados: Houve diferença estatisticamente significativa (p<0.05) entre os diferentes grupos. A taxa de fluxo de 1 ml/min induziu as menores pressões apicais (p<0.05) quando comparada às demais taxas. Conclusão: Taxas de fluxo de 1 ml/min induziram as menores pressões apicais quando agulhas de ponta aberta foram utilizadas para irrigação (AU)

Dynamic Analysis on Static-Vibration Coupled Loading in Accelerating Orthodontic Tooth Movement / 医用生物力学

Objective To analyze stress distributions on mandible bone and periodontal ligaments during acceleration of orthodontic tooth movement by mechanical vibration, and investigate the mechanism of static-vibration coupled loading to accelerate orthodontic tooth movement. MethodsThe finite element model including tooth, periodontal ligament, cancellous bone and cortical bone was established by Mimics，SolidWorks，Geomagic and ANSYS Workbench software. Conventional static orthodontic force and low-magnitude high-frequency mechanical vibration loads were applied to the finite element model for dynamic analysis. ResultsThe compression and tension zones of alveolar bone and periodontal tissues were identified based on Y-normal stress distribution of alveolar bone and periodontal tissues, which was periodic with the same frequency as the applied low-magnitude high-frequency vibration. The von Mises stress of alveolar bone and periodontal tissues also showed periodic changes, but the compression and tension zones of alveolar bone and periodontal tissues could not be identified based on von Mises stress distribution of alveolar bone and periodontal tissues. Conclusions In the field of orthodontics, Y-normal stress is a reasonable mechanical stimulus, and static-vibration coupled loading is an effective method for accelerating orthodontic treatment. The research findings can provide guidance for low-magnitude high-frequency mechanical vibration to accelerate orthodontic tooth movement.

A primary exploration for the monitoring and early warning system of hemostatic consumables / 中国医学装备

Objective: To explore how to establish a supernormal management system with functions of early warning and intervention through monitoring the dynamic state of clinical use of hemostatic consumables in the operation-decision system of hospital so as to provide reference bases for strengthening management of clinical application of hemostatic consumables in hospital. Methods: The supernormal early warning materials of the same hospital consumable in the Jan, Feb. of 2017 and the Jan, Feb. of 2016 were ranked, respectively. And the usage amount of hemostatic materials, service condition of hemostatic materials in variously clinical department and the used dynamic state of hemostatic materials in patient were carried out statistical analysis. And then, the policy suggestion of supernormal early warning intervention for hemostatic materials was primarily proposed. Results: Since the monitoring of operation-decision system of hospital for consumables was adopted, the service condition of hemostatic materials in most of clinical departments of Jan., Feb. of 2017 were better than that of Jan., Feb of 2016. Conclusion: Through the standardization construction for hospital, the clinical application management of hemostatic materials has been strengthened, and the safety, efficiency, economy and intelligent use of hemostatic materials have been ensured.

Implicit Dynamic Analysis on Tightening Procedure of Cancellous Lag Screw Placement / 医用生物力学

Objective To simulate the tightening procedure of a cancellous lag screw by using the implicit dynamic analysis method, and to evaluate the stress distributions on the screw-bone interface. Methods Finite element models of a lag screw with the surrounding bone were developed, and the implicit solver was set up for implicit dynamic analysis on the tightening procedure of the lag screw. The mechanical properties of the screw-bone interface were also analyzed according to strain and stress distributions on the screw and the surrounding bone. Results The stress of the lag screw was mainly distributed in the proximal portion of the screw thread rod. The high-stress region of the bone around the screw was located outside the outer edge of the screw, and it was approximately equal to the depth of the thread. The area of high-stress distributions on the bone was the main region that resisted screw stripping. Conclusions The method of implicit dynamic analysis can accurately simulate the mechanical properties of the screw-bone interface during screw tightening. The discovery of high-stress distributions on the surrounding bone can help researchers to further understand and improve the stability of screw insertion.

Dynamic econometrical analysis on effects of health resources inputs on residents health in Beijing / 中华医院管理杂志

Objective To learn the present status of health resources in Beijing and analyze the scale and direction of the impacts of health resources inputs on health outputs. Methods To avoid spurious regression of time sequence, macro statistics of health indicators were collected from four districts, with co-integration test and error correction model used, to analyze the impacts of health resources inputs and health demands on residents′ health outputs. Results The indicators of the number of hospital beds per thousand people, government health expenditure and disposable income of residents had positive influence on health outputs, while the ratio of doctor and nurse, and the dependency ratio of population were the two negative impacts on health. But there was no significant difference between these two negative effect indicators. Conclusions Health improvement can be promoted by increased medical and health resources, but better balance of health resources allocation is imperative among regions. More nursing personnel should be trained in order to improve the efficiency of human resource for health. The government health expenditure should be improved so as to build continuous medical service system.

Dynamic Analysis of the Temperature and the Concentration Profiles of an Industrial Rotary Kiln Used in Clinker Production

ABSTRACT Cement is one of the most used building materials in the world. The process of cement production involves numerous and complex reactions that occur under different temperatures. Thus, there is great interest in the optimization of cement manufacturing. Clinker production is one of the main steps of cement production and it occurs inside the kiln. In this paper, the dry process of clinker production is analysed in a rotary kiln that operates in counter flow. The main phenomena involved in clinker production is as follows: free residual water evaporation of raw material, decomposition of magnesium carbonate, decarbonation, formation of C3A and C4AF, formation of dicalcium silicate, and formation of tricalcium silicate. The main objective of this study was to propose a mathematical model that realistically describes the temperature profile and the concentration of clinker components in a real rotary kiln. In addition, the influence of different speeds of inlet gas and solids in the system was analysed. The mathematical model is composed of partial differential equations. The model was implemented in Mathcad (available at CCA/UFES) and solved using industrial input data. The proposal model is satisfactory to describe the temperature and concentration profiles of a real rotary kiln.

Dynamic analysis of pediatricians′ resource allocation in China from 2010 to 2015 / 中华医院管理杂志

Objective To analyze the dynamic flow of pediatricians from 2010 to 2015, their present deployment and workload as compared with physicians across the country, in order to provide reference for their effective allocation.Methods Selecting data indexes from Chinese Statistical Yearbook and China Health and Family Planning Yearbook, and using Excel for statistics of relevant index data.By means of horizontal and vertical comparisons, a dynamic analysis was made on such indexes as the number of pediatricians, that of pediatricians per thousand children, and the number of hospital admissions and the number of hospitalizations per pediatrician.Results The total of pediatricians only increased by 2.32% from 2010 to 2015.On the other hand, the number of pediatricians per thousand population only accounted for 23.42% of physicians per thousand population in 2015.These five years witnessed a 40.58% workload increase of outpatient/emergency visits per pediatrician, and 36.70% increase of discharged inpatients.Conclusions China is faced with the challenges of shortage and insufficient supply of pediatricians, worsened by excessive workloads.It is advisable to improve pediatrician development pattern, raise their remuneration, and ease their workload, for the sake of better healthcare for children.

Dynamic Analysis of the Utilization of Opioid Analgesics in Cancer Pain Inpatients of Our Hospital / 中国药房

OBJECTIVE:To provide reference for rational use of cancer pain narcotic drugs in our hospital. METHODS:The amount of narcotic drugs in our hospital was analyzed statistically during second quarter of 2012 to second quarter of 2015. RE-SULTS:12 specifications and 4 dosage forms of narcotic drugs were involved in our hospital during second quarter of 2012 to sec-ond quarter of 2015. Total amount of narcotic drugs was in an increasing tendency. Oxycodone hydrochloride sustained-release tablet was the largest quantity of narcotic drug used and grew fastest. The amount of surgical drugs kept stable,while total amount of oral preparation increased significantly,in particular,a significant increase in Morphine tablets. CONCLUSIONS:The application of narcotic drugs in our hospital is basically reasonable. The preferred oral principle has been implemented,and treatment of cancer pain is more standardized.

Dynamic analysis of the preparation of Huangqi injection / 国际中医中药杂志

Objective To dynamically the preparation process of Huangqi injection and to verify the rationality and existing problems of the process. Methods The preparation was made by the current standard (WS3-B-3335-98) issued by Ministry of Health, and the solid amount of the key processes were measured. The HPLC separation was performed on a Agilent Zorbax Bio-C18 reversed-phase column (250 mm × 4.6 mm, 5μm) in gradient mode of acetonitrile-water with UV detection at 254 nm. The column temperature was kept at 25 ℃, and the flow rate of mobile phase was 1.0 ml/min. Results Solid amounts of different operations of Huangqi injection were measured accurately. The content of the third water extracts was only 6.1%, and the changes of HPLC pointed the content of the 12 peaks of the second peaks decreased obviously. Conclusion The technological rationality of Huangqi injection need to be verified and optimized, the dynamic analysis of HPLC describes the changes of chemical constituents of Huangqi injection qualitatively, which also provides a reference value for establishing its fingerprint.

Techniques of molecular network analysis in study on network pharmacology / 国际药学研究杂志

The technology of network analysis,based on a variety of disciplines theory,is the core technology in the research of network pharmacology,through which we can mine specified information from molecular networks from multi-angle and multi-level. It has been used to investigate and obtain valuable information about the ingredients/drugs with specific pharmacological effects ,the key nodes,modules and motifs with specific biological function,and physiological mechanism of drug action,pathogenesis of dis?ease,or biomarker of disease,especially for the complex disease represented by Alzheimer′s disease(AD). In this paper,the general techniques of network analysis in network pharmacology study are reviewed.

Techniques of molecular network analysis in study on network pharmacology / 国际药学研究杂志

The technology of network analysis, based on a variety of disciplines theory, is the core technology in the research of network pharmacology, through which we can mine specified information from molecular networks from multi-angle and multi-level. It has been used to investigate and obtain valuable information about the ingredients/drugs with specific pharmacological effects, the key nodes, modules and motifs with specific biological function, and physiological mechanism of drug action, pathogenesis of disease, or biomarker of disease, especially for the complex disease represented by Alzheimer’s disease (AD). In this paper, the general techniques of network analysis in network pharmacology study are reviewed.

Dynamic analysis of white blood cells in patients with cavitary pulmonary tuberculosis during chemotherapy procedure / 国际检验医学杂志

Objective To analyze the dynamic changes of white blood cells in patients with cavitary pulmonary tuberculosis (CPTB) during chemotherapy procedure ,and explore immunological indexes which could evaluate the curative effect and prognosis . Methods 85 cases of patients with CPTB (CPTB group) and 100 healthy people conducted physical examination (control group) were enrolled in this study ,The immunological indexes of white blood cells were detected and compared between CPTB group and control group ,and dynamic changes of white blood cells were analyzed in patients with CPTB .Results Compared with the control group ,absolute lymphocyte count and percentage of lymphocyte were decreased in the CPTB group before chemotherapy ,while the total white blood cells count ,absolute neutrophil count and percentage of neutrophil ,absolute monocyte count and percentage of monocyte were increased in the CPTB group before chemotherapy ,there were statistically significant differences between the two groups(P<0 .05) .Except the absolute lymphocyte count ,other indexes were statistically increased or decreased during chemothera‐py procedure .Conclusion After chemotherapy ,the immunological reactions induced by lymphocyte are under inhibitory state .The dynamic changes of white blood cells could reflect the state of cellular immunity in patients with CPTB during chemotherapy ,which could be helpful for the evaluation of curative effect and prognosis .

Dynamic analysis on endo phylohormone during bolting time of roots in Saponikovia cata / 中草药

Objective: Through determining the contents of growth hormone (IAA), gibberellic acid (GA), and abscisic acid (ABA) to make the content changes of IAA, GA, and ABA clear before and after bolting time in the roots of Saponikovia cata, so as to provide the theoretical basis for studying the early bolting mechanism in the roots of S. cata. Methods: The contents of IAA, GA, and ABA before and after the bolting time were determined by HPLC. The chromatographic conditions were as follows: C18 ODS RP column, temperature: 35°C, detection wavelength: 254 nm, volumn flow: 0.7 mL/min, mobile phase: methanol-acetonitrile -0.7% acetic acid (40:15:45). Results: The content variation trend of IAA and GA in the roots, stems, and leaves of S. cata was almost the same during the bolting time. The contents of IAA and GA in the roots of S. cata revealed the downgrade tendency sharply after bolting; The contents of IAA and GA in the roots of S. cata before bolting were obviously higher than those after bolting. The content variation trends of ABA in the roots, stems, and leaves of S. cata were the same during the bolting time, but far more different from IAA and GA. Although there was the little fluctuation of ABA before bolting, the contents of ABA after bolting were sharply upgraded and were obviously higher than those before bolting. Conclusion: The phenomenon of early bolting in the roots of S. cata directly relates to the endo phylohormone level, so we may extrapolate that the levels of endo phylohormone could straightly cause the bolting in the roots of S. cata or not.

Classificação de sinais de vozes saudáveis e patológicas por meio da combinação entre medidas da análise dinâmica não linear e codificação preditiva linear / Healthy and pathological voice assessment by means of nonlinear dynamic analysis measures and linear predictive coding

Análise acústica tem sido sugerida como uma ferramenta auxiliar não invasiva e de baixo custo ao diagnóstico de patologias laríngeas. Diversas são as técnicas empregadas, entre as quais técnicas baseadas no modelo linear de produção da fala e na análise dinâmica não linear de sinais de vozes. O primeiro método é baseado na Teoria fonte-filtro, em que a fonte é a laringe e o filtro é o trato vocal. Nesse modelo, os sons surdos são modelados por uma fonte de ruído aleatório e os sons sonoros por um trem de impulsos na frequência fundamental do locutor. Na abordagem não linear são considerados aspectos da voz humana, não explorados no modelo linear, tais como: variação temporal da forma do trato vocal, as ressonâncias associadas à sua fisiologia, as perdas devido ao atrito nas paredes internas do trato vocal, a radiação do som nos lábios, o acoplamento nasal e o comportamento dinâmico associado à vibração das pregas vocais. Neste trabalho são associadas as duas abordagens e avaliado o desempenho na classificação com as características, de forma individual, e a partir da combinação das mesmas. São empregadas oito medidas oriundas da análise dinâmica não linear (dimensão de correlação, quatro medidas de entropia, expoente de Hurst, maior expoente de Lyapunov e o primeiro mínimo da função de informação mútua), além de coeficientes LPC, obtidos a partir da análise preditiva linear. Os resultados sugerem a viabilidade da técnica empregada para a discriminação entre vozes saudáveis e patológicas em geral, como também entre vozes afetadas por patologias laríngeas distintas como edema, nódulos e paralisia nas pregas vocais.

Acoustic analysis has been suggested as a noninvasive aiding and low cost tool for laryngeal disease diagnosis. Several techniques are employed using either the linear model of speech production, or the nonlinear dynamic analysis of voice signals. The first method is based on source-filter theory, in which the source is the larynx and the filter is the vocal tract. In this model, the unvoiced sounds are modeled by a random noise source and the voiced ones by impulse train at the speaker fundamental frequency. In nonlinear approach, aspects of the human voice are considered, not explored in the linear model, such as temporal variation of the vocal tract shape, resonances associated with its physiology, losses due to friction in the vocal tract inner walls, sound radiation in the lips, nose coupling and dynamic behavior associated with vocal fold vibration. This work combines the two approaches and evaluates the performance in classifying the features individually, and from their combination. Eight measures are employed derived from the nonlinear dynamic analysis (correlation dimension, four entropy measures, Hurst exponent, the largest Lyapunov exponent and the first minimum of mutual information function), besides LPC coefficients obtained from linear predictive analysis. The results suggest the feasibility of the employed technique to discriminate between healthy and pathological voices in general, but also among specific laryngeal diseases as vocal fold edema, nodules and paralysis.

Dynamic analysis on comprehensive quality progress effectiveness of military medical undergraduates of different sorts / 中华医学教育探索杂志

Objective To compare the effort intensities in comprehensive quality development of military medical undergraduates of different sorts and to discuss its improvement.Methods Comprehensive quality of undergraduates of 2010 grade (630 persons including 16 cadres) was assessed by comprehensive quality assessment index system.Based on data envelopment analysis,ratio of actual output (comprehensive quality development) against ideal value was taken as progress effectiveness to reflect the comprehensive development.SPSS 16.0 software was used for statistical processing and analysis.Score of each quality was analyzed and nondimensionalize was performed.Undergraduates' progress effectiveness was compared using analysis of variance.Results In September 2011,progress effectiveness of undergraduates without military status was higher than that of soldiers in comprehensive quality,ideology and morality,science,culture,profession,psychological quality and basic ability (F =34.659,49.234,119.273,12.641,103.814,65.105,P ＜ 0.001).Progress effectiveness in the former was higher than that of the latter in physical fitness.(F =7.363,P ＜ 0.01).In March 2012,progress effectiveness of undergraduates without military status was higher than that of soldiers in comprehensive quality,ideology and morality,science,culture,profession,psychological quality,basic ability and physical fitness (F =28.017,10.847,33.559,24.630,48.767,10.460,38.251,P ＜0.01).Conclusions Comprehensive quality development of undergraduates is a continuous dynamic course.One year's observation shows that at early stage,all qualities of undergraduates without military status improve quickly except physical fitness with more subjective efforts.The two sorts of undergraduates belong to forward effect.

Protocolo para el análisis funcional de prótesis para pacientes con amputación parcial de pie / Protocol for the Functional Analysis of Prosthesis in Patients with Partial Foot Amputation

En la actualidad el desarrollo de prótesis presenta problemas que aún no se han solucionado por completo. A pesar de que se han desarrollado varios estudios enfocados a evaluar el funcionamiento de las prótesis, los trabajos que se presentan en la literatura se realizan con suposiciones de carga, de materiales, e incluso se practican bajo condiciones estáticas. La técnica de correlación de imágenes digitales ha sido útil en diversas aplicaciones, pero ha sido poco explorada en el ambiente de las prótesis. En este trabajo se presenta una técnica capaz de medir la deformación real en sistemas protésicos de pacientes amputados, bajo condiciones de carga y postura reales. Empleando el método de correlación de imágenes digitales es posible evaluar la prótesis del paciente sin necesidad de instrumentarla o modificarla. Además es posible conocer los principales puntos de deformación sin tener que fracturar la pieza. Con esta técnica es posible medir las principales zonas de deformación de un sistema protésico, con la ventaja de que la evaluación se pueden llevar a cabo aplicando cargas y posturas reales de un paciente en un análisis dinámico.

At present, the development of prostheses presents problems that have yet to be completely solved. Despite that various studies have been developed to evaluate the functioning of these prostheses, the works presented in the literature are conducted with suppositions of burden, of materials, and are even practiced under static conditions. The technique of Digital image correlation (DIC) has been useful in diverse applications, but has been scarcely explored in the ambience of prostheses. In this work, we present a technique capable of measuring the real deformation of prosthetic systems in patients with amputations, under real conditions of load and posture. Employing the DIC method, it is possible to evaluate a patient?s prosthesis without the need for instrumenting or modifying it. In addition, it is possible to know the main points of deformation without having to ultimate load the piece. With this technique, it is possible to measure the prosthetic system?s main deformation zones, with the advantage that evaluation can be performed applying the real loads and postures of a patient in a dynamic analysis.

Dynamic analysis of Oncomelania snail distribution in Jiangsu Province,2004-2008 / 中国血吸虫病防治杂志

Objective To analyze the characteristics and changes of Oncomdania snail distribution in regions with different epidemic types and degrees of Jiangsu Province,so as to provide the evidence for implementing the feasible schistosomiasis control strategy.Methods A retrespeetive survey was performed,and the 5-year database of snail status in Jiangsu Province was established based on the collected reports of snail habitat cards and schistosomiasis control in Jiangsu Province from 2004 to 2008.The changes of snail areas,infected snail aroas,infection rates of snails in different years were analyzed,and tIIe annual vailations of snail areas,infected snail areas and infection rates of snails in areas with different epidemic types and degrees were eomparedI Results The actual snail areas and infected snail areas decreased by 3 799.86 hm~2 and 2 006.35 hm~2.respectively in Jiangsu Province.2006-2008.with the annual meaan decreasing rates of 9.64% and 18.83%.Among them,the actual snail areas in marshland and lake regions,water net regions and mountainous regions decreased by 3 546.10.209.19 hm~2 and 44.57 hm~2,respectively,with the annual meall decreasing rates of 9.59%,10.29% and 11.18%,respectively.An area of 22.02 hm~2 of new snail habitatswas detected during the 5 years,and thewater net regions accounted for 89.24%.Theproportions of actual snail areas in historical snail ale,as were between 2.77% and 5.36%.Among them.the proportions of actual snail areas in historical accumulative snail area8 in transmission-uncontrolled.trailsmission-controlled and transmission-interrupted areas were 13.29%-22.82%,0.88%-3.54% and 0.14%-0.32%,respectively,and there were significant differences among them(P<0.01).The constituent ratios of the actual snail areaswere 93.79%-95.60%.3.67%-5.45% and 0.73%-1.01%, respectively in marshland and lake regions,water net regions and mountainous regions from 2004 to 2008.The infection rate of snails in Jiangsu Province reduced from 0.15% in 2004 to 0.02% in 2008,with a reduction rate of 85.50%(P<0.01).The constituent ratios of infected snail areas in transmission-uncontrolled, transmission-controlled and transmission-interrupted areas were 98.15%-100%,0-0.81%, and 0-1.43%,respectively.Conclusions As a whole,there is a decreasing tendency of snail areas and infected snail areas in Jiangsu Province.and the snail control has been consohdated step by step in transmission-interrupted areas.The effective control of snails in marshland and lake regions and infected snails in transmission-uncontrolled areas are the key points in the future schistosomiasis control of Jiangsu Province.

Dynamic analysis on impacting during baseball batting / 医用生物力学

Objective By a thorough analysis of the baseball batting to provide a theoretical instruction for baseball players with a simple and efficient dynamic model. Method Based on the moment of impulse theory, the closed form linear equations were derived by the dynamic analysis of the hinged multi-rigid body model. The numerical results would be obtained after solving the equations. Results (1) The batting speeds have been obtained by the numerical calculation under various conditions of different initial speeds of the baseball and bat; (2) The knockout speeds of wood bats are much smaller than the aluminum ones; (3) The coefficient of restitution has the significant effect on the batting speeds, and has no effects on sweet spot and center of position. Conclusions The numerical results are consistent with the data of experiments in reference. The calculating procedure is easy for baseball coaches and players to understand and can be applied in the training of baseball batting directly.

Experimental study on the half-squat parachute landing for driving and validating the inverse dynamic simulation / 医用生物力学

Objective To provide data for establishing, driving and validating the inverse dynamics model of AnyBody Modeling System, the simulated half squat parachute landing experiment was designed and relevant data were collected. Method The subject was required to jump from a 0.32 m high platform to simulate the half squat parachute landing. The kinematic parameter of lower extremity joint, the ground reaction force and the surface electromyogram (SEMG) of four main muscles in the lower extremity joint were measured simultaneously. Results The angle changes of hip, knee and ankle along with time in three anatomical planes, the ground reaction force of right foot and the trajectory of the center of pressure were collected within 1 second just before and after the subject landing. These data would be used to drive the muscleskeletal model, while the data for measuring electromyogram activity would be used to validate the model. Conclusions The experiment meets the requirement of muscleskeletal model analysis, which can be used for further study of half squat parachute landing.