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1.
人体跟骨冲击损伤的生物力学研究   总被引:4,自引:0,他引:4  
目的探讨人体跟骨在冲击载荷作用下跟骨损伤的机制,为指导临床手术、固定和康复服务。方法建立跟骨动力学实验模型,采集20例新鲜人体尸跟骨标本,进行冲击实验。结果根据实验结果,得到了高速冲击载荷作用下人体跟骨的动态冲击响应,测量了人体跟骨冲击动力学性质,跟骨压缩性应变形成的粉碎性骨折。结论结果表明有必要建立人体跟骨损伤标准,包括跟骨生物力学冲击响应、骨粘弹性性质、决定伤害容限,评估损伤防护体系。  相似文献   

2.
模拟舰船冲击对人体下肢骨骼轴向压缩损伤特性研究   总被引:2,自引:0,他引:2  
目的非接触性水下爆炸在极短的时间内产生巨大的加速度,引起舰船装备的破坏和人员严重损伤,尤其是人员下肢骨骼极易受到冲击损伤,严重影响舰船战斗力。材料与方法为了研究舰船冲击运动对人体下肢主要骨骼的损伤,采用12具新鲜的下股骨骼(包括股骨、胫骨、距骨、腓骨、跟骨)人体尸体标本,模拟舰船冲击运动的特性,在冲击机上进行静态和动态压缩测试实验。结果获取人体下股骨骼在静态和动态载荷作用下的压缩特性,如破坏载荷、压缩变形等,并对数据进行分析计算,得到下肢骨骼过载加速度估算值、骨骼损伤特点、动荷系数等参数,提出现有的下肢骨骼的冲击损伤耐受性及标准。结论在人体下肢骨骼中,跟骨和股骨的破坏载荷应是最低的,其动态抗压性能也较差,这与舰船冲击伤以跟骨及股骨损伤发生率较高的实际情况相符合。  相似文献   

3.
目的利用膝关节有限元模型和模拟跳伞着陆实验数据,对半蹲式跳伞着陆过程进行数值模拟,并分析膝关节损伤的机理。方法对16名健康志愿者进行半蹲式模拟跳伞实验,跳落高度分别为0.32m,0.52m和0.72m。基于核磁共振成像建立人体膝关节的三维有限元模型,采用实验测得的膝关节运动学和地面反力数据对跳伞着陆过程进行数值模拟。结果关节内组织的应力水平随着跳落高度的增加而增加,外侧半月板和关节软骨承受了较大的载荷,前交叉韧带和内侧副韧带在屈膝角度达到最大时产生明显的应力集中。结论跳伞着陆的高速冲击是造成关节损伤的直接原因,外侧关节软骨和半月板更易受到损伤,前交叉韧带和内侧副韧带较易在屈膝幅度最大时发生撕裂。  相似文献   

4.
为了验证汽车碰撞过程中人体颈部的损伤情况,建立了人体颈椎C4-C6部分有限元生物力学模型,模型组织包括皮质骨、松质骨、纤维环、髓核、韧带以及关节面,并在各组织接触部位设置了接触,以便更好地模拟模型在前冲击下的运动趋势。对模型施加前冲击载荷,研究各组织的应力及应变分布情况。经过验证,模型在前冲击过程中,其位移模拟数据基本在实验数据区间范围内,模拟了颈椎C4-C6部分在前冲击载荷下的运动趋势,具有较好的生物逼真度,基本反映了人体颈部冲击动力学响应。  相似文献   

5.
目的 构建并验证含动脉的骨盆-股骨-软组织复合体的三维有限元模型,研究骨盆动脉在侧向冲击条件下的力学响应。方法 基于1名女性志愿者的骨盆CT图像,建立骨盆及其动脉的三维有限元模型,包括骨、动脉、周围软组织以及骶髂关节、髋关节和耻骨联合等骨盆关节软骨和韧带。采用线弹性实体单元模拟骨骼,采用非线性的弹性连接单元模拟韧带,软组织包括软骨、包裹软组织和动脉等采用超弹性材料和实体单元仿真。以22.1 kg的冲击质量,3.13和5 m/s的冲击速度对坐位下的复合体进行侧面碰撞,记录模型的输出。结果 计算结果与文献报道的实验结果一致。3.31和5 m/s冲击速度下动脉的最大等效应力分别为98和216 kPa,最大拉伸应变为14.9%和20%,但不至于导致动脉断裂。结论 所建立的骨盆-股骨-软组织复合模型可用于冲击载荷下骨盆动脉的动态响应和损伤分析,为预测动脉损伤程度提供生物力学依据。  相似文献   

6.
目的 探讨头部肌肉及边界条件对头部碰撞动态响应的影响。方法 通过人体扫描CT图片构建3种人体头部三维物质点碰撞模型,第1种为简化的自由头部模型(SHFr),包括头骨、膜层、脑组织,头部自由;第2种为带肌肉的自由头部模型(MHFr),包括头部肌肉、头骨、膜层、脑组织,头部自由;第3种为带肌肉的肩部固定的模型(MHSFi),包括头部肌肉、头骨、膜层、脑组织、肩部肌肉、肩颈部骨骼,肩部下缘固定。一铅质圆柱体锤以6.4 m/s初始速度垂直撞击前额部位,通过物质点法模拟计算3种模型的动态响应。结果 在本数值模拟条件下,SHFr、MHFr、MHSFi 3种模型的头部加速度峰值分别为6.018×103、4.69×103、4.76×103 m/s2。结论 头部肌肉的存在会分散头部的受力分布,扩大头部受力面积,减小受伤程度;在短时间冲击过程中,头部自由与肩部固定对头部动态响应的影响不大。  相似文献   

7.
根据乘员碰撞事故中人体膝关节的生物力学响应特性,应用有限元(FE)方法和碰撞模拟技术,构建了一个人体膝关节模型。模型按人体解剖学结构构建,由股骨内、外侧髁,胫骨内、外侧髁,腓骨小头、髌骨、软骨、半月板以及主要韧带构成。通过比较模型仿真和尸体碰撞实验在轴向载荷条件下膝关节受刚性碰撞的响应结果,验证了模型的有效性。该模型为研究人体膝关节损伤机理提供了可靠的基础数据,并可应用于乘员损伤防护装置的设计和开发。  相似文献   

8.
不同载荷作用下头部生物力学响应仿真分析   总被引:1,自引:0,他引:1       下载免费PDF全文
目的建立符合解剖结构的人颅骨三维有限元模型,研究多种载荷作用下头部生物力学响应。方法通过建立具有解剖结构的高精度头部有限元模型,颅骨采用能模拟骨折的弹塑性材料本构模型,结合已发表的正面冲击颅内压实验、动态颅骨骨折实验、头部跌落实验结果,仿真再现实验过程中头部受冲击载荷作用下的生物力学响应、颅骨骨折及头部不同速度下的跌落响应。结果前碰撞表现出冲击与对冲侧正-负颅内压分布,相近载荷下枕骨变形比前额、顶骨严重,跌落中速度越快损伤越大。结论建立精确解剖结构的头部有限元模型可以较好模拟头部在冲击、跌落等载荷下的生物力学响应。通过量化接触力、颅内压力等参数来评价头部损伤风险,为防护系统的设计提供科学依据。  相似文献   

9.
张敏  张露  杨梅  张英  杨济宁      秦雨萍     《中国医学物理学杂志》2023,(2):226-231
目的:分析在爆炸冲击与侧向瞬时倾倒时,人体手臂内部的损伤效应。方法:以中国数字人中肩部到指尖的727张影像数据作为数据基础,经过组织分割、三维建模以及逆抄数的方式获得组织结构几何实体,在COMSOL Multiphysics 5.5有限元仿真软件中建立人体前臂损伤机制模型,通过在载荷面加载1.4×106N/m2的冲击力,响应时间2×10-5s,以此分析前臂受到应力时的冲击力扩散机制。结果:通过建模分析发现,由于皮肤、脂肪、肌肉是粘弹性组织,当机体受到应力冲击时,应力会通过变形的方式将能量释放出来,在应力冲击下这些组织损伤并不明显。然而,由于骨骼是刚性组织,外界施加的能量在此处没法转化成位移消散,从而导致在骨骼处会有大量能量蓄积,骨骼处的应力张量最大。当应力张量超过骨骼最大承受值时,就会引起骨折来进行能量转移。结论:在应力冲击中,由于粘弹性组织可以将应力能量转化成位移来实现能量消散,而刚性组织无法实现,从而导致在应力冲击中,骨骼的损伤是非常明显的。  相似文献   

10.
目的 为了研究头部在钝器作用下的生物力学响应及损伤机理。 方法 利用CT图像数据和MRI图像数据对头部骨骼与内部软组织进行几何重建,然后画分网格,构建颅脑有限元模型。另一方面,对连于躯干的头部标本进行10 m/s的低速冲击,测试冲击部位接触力、顶部应变及冲击的对侧(枕部)加速度。把构建的有限元模型导入MADYMO软件进行相同条件下模拟仿真,从输出模块里输出相应部位的结果。 结果 仿真结果表明模型的头部接触力、顶部应变、对撞侧加速度与头部标本冲击实验测得值能较好吻合。 结论 建立的头部有限元模型及采用的仿真方法可满足头部钝器损伤的仿真研究需要。  相似文献   

11.
Renal dysplasia and asplenia in two sibs   总被引:2,自引:0,他引:2  
A family is reported in which two sibs, one male and the other female, both died within 24 hours of birth with enlarged polycystic kidneys. Postmortem histology in the second child showed gross renal dysplasia. In both children the pancreas was enlarged, nodular and cystic but the liver appeared macroscopically normal. In the second child, histological examination confirmed pancreatic fibrosis with cystic dilation of ducts, but showed portal fibrosis with bile duct proliferation in the liver.
This combination of findings is very reminiscent of those in a girl and her brother reported by Ivemark et al. (1959). The children reported here also showed absence or hypoplasia of the spleen, cardiac anomalies and other features of the Ivemark syndrome (Ivemark 1955), a quite different, usually sporadic, congenital disorder. It is suggested that the children described here have a distinct lethal congenital disorder, probably inherited in an autosomal recessive manner.  相似文献   

12.
Over 200 schizophrenic patients belonging to three major and interrelated pedigree complexes have been investigated over the past 30 years in a North Swedish geographically isolated population, presently numbering about 6,000. An intensive investigation of a number of biochemical correlates and genetic markers in a few selected families belonging to one of the major pedigrees has indicated new strategies for the current research program.
Schizophrenia, as defined operationally, is significantly associated with decreased activities of two enzymes (1) blood platelet monoamine oxidase, (2) plasma dopamine-β-hydroxylase, and (3) with the genetic marker Gc2 (group specific antigen). Both enzymes are subject to genetic variation. A positive score for linkage between schizophrenia and low plasma DBH activity has been calculated, but, so far, available data are insufficient for discrimination between linkage and partial contribution of genetically controlled low plasma DBH to the pathogenesis of the disease. Alternatively, both mechanisms could be involved.
As a model for continued research, schizophrenia is explained as based on a double dominant-recessive genotype (Aabb), representing a vulnerability which in about 50 % of cases develops into clinical schizophrenia. It is suggested that the dominant mutation (A) operates on or affects MAO activity, and that the recessive genotype (bb) is instrumental in low variates of DBH activity and very likely such variates within the normal range of physiological variation. Moreover, it is suggested that the combined effects of MAO- and DBH-reduced efficiency on the metabolism of e.g. dopamine could be an essential pathogenic mechanism for the schizophrenic illness which is segregating in this population.  相似文献   

13.
About 1900, modern food selection and processing caused widespread epidemics of the B vitamin deficiency diseases of beriberi and pellagra which, for genetic reasons, often expressed as different diseases ranging from bowel and heart disease to dermatoses and psychoses. But the B vitamins merely help convert essential fatty acids (EFA) into the prostaglandin (PG) tissue regulators and it now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, we have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA (w3) of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA. Since substrate EFA is processed by many B vitamin catalysts, an EFA deficiency will mimic a panhypovitaminosis B, i.e., a mixture of substrate beriberi and substrate pellagra resembling vitamin beriberi and pellagra but exhibiting as even more diverse endemic disease. This would consitute a second stage of the Modern Malnutrition and explain why some workers now hold the dominant diseases of modermized societies to be new, nutritionally based, pellagraform yet lipid-related and to range, once again, from heart disease to psychosis. It is an assumption that our dominant diseases are unrelated to each other or are merely revealed by our diagnostic acumen and therapeutic success; and that hydrogenating millions of tons of food oils annually, to destroy the rancidity producing w3-EFA, is safe for primates. Extensive beriberiform disease is reported here in 32 typical cases taken from medical practice which responds strikingly to linseed oil supplements (60% w3-EFA) in confirmation of identical results in Capuchins.  相似文献   

14.
15.
Recent advancements in agricultural biotechnology have created a need for analytical techniques to determine introduced proteins in crops enhanced through modern biotechnology techniques. These proteins are expressed in plant tissues and may be present in food ingredients. Immunoassays are ideally suited for protein detection and may be used as both quantitative and threshold methods. Microplate ELISA and lateral flow devices are two of the most commonly used immunoassay formats for agricultural biotechnology applications. This paper provides general background information and a discussion of criteria for the validation and application of immunochemical methods to the analysis of proteins introduced into plants and food ingredients using biotechnology methods. It is the result of a collaborative effort of members of the Analytical Environmental Immunochemical Consortium. This collaborative effort represents the combined expertise of several organizations to reach consensus on establishing guidelines for the validation and use of immunoassays. Further, the paper offers developers and users a consistent approach to adopting the technology as well as aid in producing accurate and meaningful results.  相似文献   

16.
Newton H 《Medical history》2011,55(2):153-182
Sick children were ubiquitous in early modern England, and yet they have received very little attention from historians. Taking the elusive perspective of the child, this article explores the physical, emotional, and spiritual experience of illness in England between approximately 1580 and 1720. What was it like being ill and suffering pain? How did the young respond emotionally to the anticipation of death? It is argued that children’s experiences were characterised by profound ambivalence: illness could be terrifying and distressing, but also a source of emotional and spiritual fulfilment and joy. This interpretation challenges the common assumption amongst medical historians that the experiences of early modern patients were utterly miserable. It also sheds light on children’s emotional feelings for their parents, a subject often overlooked in the historiography of childhood. The primary sources used in this article include diaries, autobiographies, letters, the biographies of pious children, printed possession cases, doctors’ casebooks, and theological treatises concerning the afterlife.  相似文献   

17.
The preparation steps usually necessary for obtaining ultrathin frozen sections of biological material (chemical prefixation, enclosing, cryoprotective treatment, freezing, sectioning, and post-staining the sections for transmission electron microscopy) are submitted to a critical analysis. The application of cryo-ultramicrotomy, in particularly for cytochemical purposes, is reviewed. Fundamental considerations of chemical prefixation and poststaining are supported by examples from yeast cytology. Furthermore, the efficiency of the cryo-ultramicrotomy (electron optical resolution of ultrastructural details) is demonstrated on yeast cells and protoplasts.  相似文献   

18.
There is a sharp difference in how one views TCR structure–function–behaviour dependent on whether its recognition of major histocompatibility complex‐encoded restriction elements (R) is germline selected or somatically generated. The generally accepted or Standard model is built on the assumption that recognition of R is by the V regions of the αβ TCR, which is not driven by allele specificity, whereas the competing model posits that recognition of R is allele‐specific. The establishing of allele‐specific recognition of R by the TCR would rule out the Standard model and clear the road to a consideration of a competing construct, the Tritope model. Here, the case for allele‐specific recognition (germline selected) is detailed making it obvious that the Standard model is untenable.  相似文献   

19.
Zusammenfassung Die Lagerung des Körpers hat wesentlichen Einfluß auf die Balance der transkapillären Bewegung eiweißarmer Flüssigkeit, das heißt auf das Gesamt-Starling-Gleichgewicht im Kreislauf. Aufrichten aus der horizontalen Lage hat Hämokonzentration, Hinlegen Hämodilution zur Folge. Folglich beeinflußt Lageänderung das Blut- und Plasmavolumen und darüber hinaus Werte wie Eiweißkonzentration, Hämatokrit oder Hämoglobinkonzentration im Blut.In der vorliegenden Arbeit wird die Möglichkeit vorgestellt, mittels der Biegeschwingermethode durch Dichtemessungen an Kapillarblut und -plasma diese orthostatischen Einflüsse auf hämatologische Zustandsvariable zu quantifizieren und ihren zeitlichen Verlauf mit hoher Auflösung zu erfassen.Im Durchschnitt ergab sich infolge Aufrichten des Körpers (70°) aus der Horizontalen eine Verringerung des Plasmavolumens um 6,6% nach 10 und um 11,1% nach 30 min; Hinlegen bewirkte nach 10 min eine Erhöhung des Plasmavolumens um 6,5% und nach 30 min um 10,5%. Entsprechende Blutvolumenveränderungen zwischen 5 und 10% gingen auch aus den Blutdichteänderungen bei orthostatischen Reizen hervor.Eine wichtige praktische Konsequenz ist die Forderung nach Beachtung der Körperlage vor und während Blutabnahmen, vor allem bei Verlaufsmessungen hämatologischer Größen bei ein und demselben Patienten oder bei statistischen Vergleichen verschiedener Kollektive.Diese Arbeit wurde vom Fonds zur Förderung der Wissenschaftlichen Forschung unterstützt  相似文献   

20.
There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub-Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide-treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.  相似文献   

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