Development of a dynamic index finger and thumb model to study impairment

Modeling of the human hand provides insight for explaining deficits and planning treatment following injury. Creation of a dynamic model, however, is complicated by the actions of multi-articular tendons and their complex interactions with other soft tissues in the hand. This study explores the creation of a musculoskeletal model, including the thumb and index finger, to explore the effects of muscle activation deficits. The OpenSim model utilizes physiological axes of rotation at all joints, passive joint torques, and appropriate moment arms. The model was validated through comparison with kinematic and kinetic experimental data. Simulated fingertip forces resulting from modeled musculotendon loading largely fell within one standard deviation of experimental ranges for most index finger and thumb muscles, although agreement in the sagittal plane was generally better than for the coronal plane. Input of experimentally obtained electromyography data produced the expected simulated finger and thumb motion. Use of the model to predict the effects of activation deficits on pinch force production revealed that the intrinsic muscles, especially first dorsal interosseous (FDI) and adductor pollicis (ADP), had a substantial impact on the resulting fingertip force. Reducing FDI activation, such as might occur following stroke, altered fingertip force direction by up to 83° for production of a dorsal fingertip force; reducing ADP activation reduced force production in the thumb by up to 62%. This validated model can provide a means for evaluating clinical interventions.     

Inferior parietal somatosensory neurons coding face-hand coordination in Japanese macaques

Neuronal activities of the anterior part of the inferior parietal lobule (area 7b or PF) were investigated in five awake Japanese monkeys. There were neurons which had specific combinations of receptive field (RF) locations, most typically in both the face and hand; we refer to these as Face-Hand neurons. The most interesting property of the Face-Hand neurons is that some of these neurons responded to specific behavior executed with synergism between the face (especially the mouth) and hand movements; namely, face-hand coordinated behavior (e.g., eating behavior). We call these cells Face-Hand coordination neurons (52% of all the Face-Hand neurons). These neurons discharged more strongly when the animal executed face-hand coordinated behavior, especially eating behavior, than when somatosensory stimuli were given to RFs passively, or when face movements and hand movements were executed separately. We thus propose that the neuronal activities of area 7b are related to the representation of face-hand coordination.     

Functional and morphological affinities of the subadult hand (O.H. 7) from Olduvai Gorge.

Study of the O.H. 7 hand was based primarily on morphological comparisons with a large series of hand skeletons of extant hominoid primates. Most of the hand elements are fragmentary or have missing epiphyses and only comparisons based on qualitative morphological observations are possible. The distal phalanges are complete, however, and were analyzed metrically utilizing univariate and multivariate statistical techniques. To compensate for size differences among the Hominoidea a number of size adjustments were employed. None of the adjustments were totally satisfactory from theoretical and practical standpoints and none completely eliminated the influence of size. There is no entirely satisfactory procedure to eliminate size and it is advisable to use several techniques that are not closely related, to compare the results and interpret them with caution. In certain features the wrist and fingers resemble those of African apes; in others they are more like modern human hands; in still others they are unique. The scaphoid and the proximal articular surface of the trapezium retain ape-like features, as do the proximal and middle phalanges. The pollical carpometacarpal joint and the distal phalanges are closer in morphology to those of modern humans. The scaphoid, proximal phalanges and middle phalanges of rays II-V indicate a hand capable of a strong power grip. A number of features of the thumb and the distal phalanges suggest that the O.H. 7 individual was capable of more precise manipulation that extant apes. FLK NN-A, a first distal phalanx, does not closely resemble the first distal phalanx of any of the living Hominoidea. Multivariate distance analysis indicates, however, that it is closest in overall morphology to the pollical distal phalanx of modern humans. In some features not included in the metric analysis, FLK NN-A also resembles the hallucial distal phalanx of modern humans.     

布依族人手的应用人类学研究

本文探讨了布依族人手的形态特征, 为体质人类学积累资料和整形外科、机械设备、工具制造、手防护用具等设计提供形态学依据。采用国际通用的手部测量方法, 测量了312名(男153,女159) 布依族人手44项指标。所测数据均为男性大于女性(P<0.01), 测量项目右侧大于左侧的男性为75%, 女性为81.82%; 手形厚度、围度、长度和宽度差异均具有统计学意义(P<0.05或P<0.01); 掌指数男性为96.56、女性为93.84, 手指数男性为46.12、女性为45.66。结果表明, 布依族人手形态具有左右侧非对称性和明显的性别差异; 手型呈短宽型, 指型呈短粗型。     

汉族湘语族群的7项不对称行为特征

在湖南省娄底地区调查了汉族湘语族群507例(男269例、女238例)高中学生的7项不对称行为特征(扣手、利手、叠臂、叠腿、利足、起步类型和优势眼)。研究结果显示:1)湘语族群叠臂与起步类型L型率高于R型率, 其余5项均R型率高于L型率。2)湘语族群利手、叠臂、利足出现率存在性别间差异, 其余4项出现率均不存在性别间差异。3)在已发表的资料中, 湘语族群扣手和起步类型右型率中等偏高, 利手右型率处于中等水平, 叠臂和叠腿右型率低,利足和优势眼右型率高。4)主成分分析结果显示, 汉族各族群不对称行为特征有一定的共性, 相对接近于中国北亚类型族群, 而与南亚类型族群差距较大。中国族群间不对称行为特征的差异, 主要反映在叠臂率差异、利足率差异。     

Conditional deletion of Hand2 reveals critical functions in neurogenesis and cell type-specific gene expression for development of neural crest-derived noradrenergic sympathetic ganglion neurons

Neural crest-derived structures that depend critically upon expression of the basic helix-loop-helix DNA binding protein Hand2 for normal development include craniofacial cartilage and bone, the outflow tract of the heart, cardiac cushion, and noradrenergic sympathetic ganglion neurons. Loss of Hand2 is embryonic lethal by E9.5, obviating a genetic analysis of its in-vivo function. We have overcome this difficulty by specific deletion of Hand2 in neural crest-derived cells by crossing our line of floxed Hand2 mice with Wnt1-Cre transgenic mice. Our analysis of Hand2 knock-out in neural crest-derived cells reveals effects on development in all neural crest-derived structures where Hand2 is expressed. In the autonomic nervous system, conditional disruption of Hand2 results in a significant and progressive loss of neurons as well as a significant loss of TH expression. Hand2 affects generation of the neural precursor pool of cells by affecting both the proliferative capacity of the progenitors as well as affecting expression of Phox2a and Gata3, DNA binding proteins important for the cell autonomous development of noradrenergic neurons. Our data suggest that Hand2 is a multifunctional DNA binding protein affecting differentiation and cell type-specific gene expression in neural crest-derived noradrenergic sympathetic ganglion neurons. Hand2 has a pivotal function in a non-linear cross-regulatory network of DNA binding proteins that affect cell autonomous control of differentiation and cell type-specific gene expression.     

九牛造杀虫活性成分研究

无公害农药具有杀虫活性高、无污染、与环境相容性好等特点,开发此类农药具有重要意义[1,2].     

The effects of wrist motion and hand orientation on muscle forces: A physiologic wrist simulator study

Although the orientations of the hand and forearm vary for different wrist rehabilitation protocols, their effect on muscle forces has not been quantified. Physiologic simulators enable a biomechanical evaluation of the joint by recreating functional motions in cadaveric specimens. Control strategies used to actuate joints in physiologic simulators usually employ position or force feedback alone to achieve optimum load distribution across the muscles. After successful tests on a phantom limb, unique combinations of position and force feedback – hybrid control and cascade control – were used to simulate multiple cyclic wrist motions of flexion-extension, radioulnar deviation, dart thrower’s motion, and circumduction using six muscles in ten cadaveric specimens. Low kinematic errors and coefficients of variation of muscle forces were observed for planar and complex wrist motions using both novel control strategies. The effect of gravity was most pronounced when the hand was in the horizontal orientation, resulting in higher extensor forces (p < 0.017) and higher out-of-plane kinematic errors (p < 0.007), as compared to the vertically upward or downward orientations. Muscle forces were also affected by the direction of rotation during circumduction. The peak force of flexor carpi radialis was higher in clockwise circumduction (p = 0.017), while that of flexor carpi ulnaris was higher in anticlockwise circumduction (p = 0.013). Thus, the physiologic wrist simulator accurately replicated cyclic planar and complex motions in cadaveric specimens. Moreover, the dependence of muscle forces on the hand orientation and the direction of circumduction could be vital in the specification of such parameters during wrist rehabilitation.