Molecular characterization and determination of the coding capacity of the genome of equine herpesvirus type 2 between the genome coordinates 0.235 and 0.258 (theEcoRI DNA fragment N; 4.2 kbp)

The complete DNA nucleotide sequence of theEcoRI DNA fragment N (0.235 to 0.258 viral map units) of equine herpes virus type 2 (EHV-2) strain T400/3 was determined. This DNA fragment comprises 4237 bp with a base composition of 55.23% G+C and 44.77% A+T. Nineteen open reading frames (ORFs) of 50-287 amino acid (aa) residues were detected. ORF number 10 is located between the nucleotide position 2220 and 2756 coding for a protein of 179 amino acid residues. This protein shows significant homology to the cytokine synthesis inhibitory factor (CSIF; interleukin 10) of human (76.4%) and mouse (68.5%), and to the Epstein-Barr virus (EBV) protein BCRF1 (70.6%). The existence of an interleukin 10 (IL-10) analogous gene within the genome of the EHV-2 was confirmed by screening the genome of nine EHV-2 strains using specific oligonucleotide primers corresponding to the 5 and 3 region of this particular gene by polymerase chain reaction. In all experiments an 870 bp DNA product was amplified. The specifity of the amplified DNA fragments obtained from individual EHV-2 strains was confirmed by DNA-DNA hybridization experiments. The DNA sequence analysis of the amplified DNA products of the EHV-2 strain LK was carried out. This analysis revealed the identity of the corresponding IL-10 gene (540 bp) of this strain to the IL-10 gene of EHV-2 strain T400/3. The presented data indicate that the EHV-2 genome harbors a viral interleukin 10-like gene. This is further evidence that the IL-10 gene can be present in the genomes of members of the Herpesviridae family.     

血清中Zn,Cu,Mn,Cr和Se微量元素与口腔恶性肿瘤的关系

本研究测定与肿瘤关系密切的微量元素Ｚｎ、Ｃｕ、Ｍｎ、Ｃｒ和Ｓｅ在口腔颌面部正常者与良、恶性肿瘤患者血清中含量共９１例。结果表明微量元素Ｚｎ、Ｃｕ、Ｍｎ、Ｃｒ和Ｓｅ在口腔颌面部肿瘤与其它部位肿瘤一样有明显变化。用模式识别方法以微量元素作为指标，对良恶性肿瘤进行鉴别诊断，有一定的临床意义。     

内骨架一体化小腿假肢的生物力学研究

一体化假肢是以聚合物为材料从接受腔到假腿一体成型的新型下肢假肢，它比传统型假肢更经济、美观、轻便，具有较大的应用前景。目前的相关研究主要集中在设计与制作及少量的临床研究方面。由于一体化假肢与传统型假肢在结构上的差异，有必要对其进行应力分析。本研究的目的是开展内骨架一体化假肢的生物力学研究，本研究基于内骨架一体化小腿假肢的真实几何构型，建立三维有限元模型，计算该模型在模拟Heel OH步态时相的载荷作用下的应力分布；在保持该模型的几何形状不变的情况下，建立了三个不同壁面厚度的一体化小腿假肢的有限元模型，分析壁面厚度对一体化小腿假肢应力分布的影响；通过分别赋予模型四种不同高分子聚合物的材料力学特性值，分析不同材料的一体化假肢的应力分布特点；分别对模型施加与正常步态的五个典型时相对应的载荷，分析一体化小腿假肢在各步态时相的应力分布特点。本研究结果对一体化假肢设计有指导价值。     

Trabecular Shear Stresses Predict <Emphasis Type="Italic">In Vivo</Emphasis> Linear Microcrack Density but not Diffuse Damage in Human Vertebral Cancellous Bone

Linear microcracks and diffuse damage (staining over a broad region) are two types of microscopic damage known to occur in vivo in human vertebral trabecular bone. These damage types might be associated with vertebral failure. Using microcomputed tomography and finite element analysis for specimens of cancellous bone, we estimated the stresses in the trabeculae of human vertebral tissue for inferosuperior loading. Microdamage was quantified histologically. The density of in vivo linear microcracks was, but the diffuse damage area was not, related to the estimates of von Mises stress distribution in the tissue. In vivo linear microcrack density increased with increasing coefficient of variation of the trabecular von Mises stress and with increasing average trabecular von Mises stress generated per superoinferior apparent axial stress. Nonlinear increase in linear crack density, similar to the increase of the coefficient of variation of trabecular shear stresses, with decreasing bone stiffness and bone volume fraction suggests that damage may accumulate rather rapidly in diseases associated with low bone density due to the dramatic increase of shear stresses in the tissue. © 2003 Biomedical Engineering Society. PAC2003: 8719Rr, 8719Xx, 8759Ls, 8759Fm, 8710+e     

数值模拟鼻甲的切除对鼻腔内气体流场的影响

量化研究鼻腔结构的变化对鼻腔内气体流场分布的影响.通过CT图像对鼻腔结构进行三维重建并用有限元方法对气体流场进行数值分析.对重建的鼻腔模型的一侧,分别去掉部分中鼻甲和部分下鼻甲并用有限元方法再次进行数值分析,将得到的结果与原始模型进行比较.观察气体流场分布的变化,在两侧鼻腔的流量分布均有变化,在去掉部分鼻甲的一侧流场和气压的分布也有所改变.通过数值模拟,我们量化的显示了鼻腔结构的变化对鼻腔内气体流场分布的影响.     

白发与黑发的微量元素分析

本文应用EPM-810Q电子探针,对53例35～60岁健康成年人白发与黑发(指长在同一部位、相邻单根白发与黑发),进行微量元素分析,结果表明:白发中Mg、Al、Cd、Ca、Cr、Mn、Fe、Se微量元素含量明显小于黑发,而Cu、Zn、Pb元素含量大于黑发。以上差异有显著性意义(P<0.001),并对上述差异进行了讨论。     

脐带血血清中六种微量元素含量的研究

本对100例健康胎儿脐带血血清中六种微量元素（锌，铁，铜，钙，镁，锰）含量进行了测定，结果提示，所测的六种元素含量在男，田性胎儿之间似无明显差异（P＞0．05），与成人比较，胎儿的锌，铁，锰含量高于成人，铜，钙含量低于成人，镁含量与成人相近。     

Morphomechanics of the humero-ulnar joint: II. Concave incongruity determines the distribution of load and subchondral mineralization

Background: A deeper joint socket (concave incongruity) is found at most angles of flexion of the humero-ulnar joint and maintained over a wide range of physiological loading. It is, however, unclear how far this incongruity affects the distribution of load and subchondral mineralization of this joint as compared with a congruous configuration. Methods: Two nonlinear, axisymmetrical finite element models with two cartilage layers were constructed, one congruous and one incongruous, with a joint space of realistic magnitude. The distribution of subchondral mineralization was determined by computed tomography osteoabsorptiometry in the same six specimens that were investigated in the first part of the study, and compared with the biomechanical data obtained there and the predictions of the models. Results: In the congruous case, the center of the socket is highly loaded, whereas the periphery does not experience mechanical stimulation. A central bone density maximum is predicted. With concave incongruity the position of the contact areas shifts from the joint margin towards the center as the load increases, and the peak stresses are considerably lower. A bicentric ventro-dorsal distribution pattern of subchondral mineralization is predicted, and this is actually found in the six specimens. Conclusions: Concave incongruity is shown to determine load transmission and subchondral mineralization of the humero-ulnar joint. It is suggested that this shape leads to a more even distribution of stress, provides intermittent stimulation of the cartilaginous tissue, and has beneficial effects on the metabolism, nutrition, and lubrication of the articular cartilage during cyclic loading. © 1995 Wiley-Liss, Inc.     

Mathematical three-dimensional solid modeling of biventricular geometry

The characterization of regional myocardial stress distribution has been limited by the use of idealized mathematical representations of biventricular geometry. State-of-the-art computer-aided design and engineering (CAD/CAE) techniques can be used to create complete, unambiguous mathematical representations (solid models) of complex object geometry that are suitable for a variety of applications, including stress-strain analyses. We have used advanced CAD/CAE software to create a 3-D solid model of the biventricular unit using planar geometric data extracted from anex vivo canine heart. Volumetric analysis revealed global volume errors of 4.7%, −1.3%, −1.6%, and −1.1% for the left ventricular cavity, right ventricular cavity, myocardial wall, and total enclosed volumes, respectively. Model errors for 34 in-plane area and circumference determinations (mean ±SD) were 5.3±6.7% and 3.8±2.7%. Error analysis suggested that model volume errors may be due to operator variability. These results demonstrate that solid modeling of theex vivo biventricular unit yields an accurate mathematical representation of myocardial geometry which is suitable for meshing and subsequent finite element analysis. The use of CAD/CAE solid modeling in the representation of biventricular geometry may thereby facilitate the characterization of regional myocardial stress distribution.     

Predicting Skull Loading: Applying Multibody Dynamics Analysis to a Macaque Skull

Evaluating stress and strain fields in anatomical structures is a way to test hypotheses that relate specific features of facial and skeletal morphology to mechanical loading. Engineering techniques such as finite element analysis are now commonly used to calculate stress and strain fields, but if we are to fully accept these methods we must be confident that the applied loading regimens are reasonable. Multibody dynamics analysis (MDA) is a relatively new three dimensional computer modeling technique that can be used to apply varying muscle forces to predict joint and bite forces during static and dynamic motions. The method ensures that equilibrium of the structure is maintained at all times, even for complex statically indeterminate problems, eliminating nonphysiological constraint conditions often seen with other approaches. This study describes the novel use of MDA to investigate the influence of different muscle representations on a macaque skull model (Macaca fascicularis), where muscle groups were represented by either a single, multiple, or wrapped muscle fibers. The impact of varying muscle representation on stress fields was assessed through additional finite element simulations. The MDA models highlighted that muscle forces varied with gape and that forces within individual muscle groups also varied; for example, the anterior strands of the superficial masseter were loaded to a greater extent than the posterior strands. The direction of the muscle force was altered when temporalis muscle wrapping was modeled, and was coupled with compressive contact forces applied to the frontal, parietal and temporal bones of the cranium during biting. Anat Rec, 291:491–501, 2008. © 2008 Wiley‐Liss, Inc.