美伤兵用上新型假肢

美国医学专家不久前为一名右腿高位截肢的伤兵安装了一条新型假肢。     

“四个自由度肌电控制全臂假肢”肩关节机构的设计

全臂假肢肩关节结构，不但要符合人手臂的外形特征，而且在结构设计的布局上还要考虑仿生性和造型的美观逼真。由于在肩关节处要承受相当大的力矩，肩关节机构要经得起前臂的较大负载外力，所以功能可靠更为重要。因此关肩节机构的 设计具有相当的难度。本机构利用蜗轮蜗杆传动的优点，来实现肩关节前屈后伸运动。克服了链传间隙大的缺点，缩短了力臂改善了肩关节处的受力状态，并且在假肢的上臂安装了上臂手动旋转环，其既可在任意     

基于脑电信号识别采集的假肢控制系统

本文介绍了脑电信号（EEG）的模式识别和步骤,分析了EEG采集领域的发展和医学原理。通过研究脑电信号和假肢运动的联系,总结脑电控制假肢的可行性结论。设计出从头皮电极到模／数转换器的基于脑电信号识别采集的假肢控制系统,能够满足脑电假肢的各种要求。     

截肢与假肢装配

截肢后则终生失去肢体的一部分,必然造成缺陷和残废。因此,在决定截肢时,应抱慎重的态度,必须严格掌握截肢的适应症。假肢能够补偿失去肢体的部分功能。假肢受残肢支配,假肢装配后能否发挥良好的功能,一方面取决于残肢条件,另一方面取决于假肢的质量,是一门医疗与工程密切结合的科学。因此要求外科医生应具有假肢装配常识,在截肢时尽可能保留一个较好的残肢,为假肢的装配创造良好的条件,争取获得最好的功能恢复。假肢制造者亦应有些人体生理解剖知识,使假肢的结构适合生物力学的要求。鉴于目前国内在医疗与工程的结合方面尚属初步,相互之间缺乏了解,因此本文对有关问题进行些讨论。     

人机共融的主动型下肢假肢分层控制策略探讨

为研究当前主动型下肢假肢控制问题的解决策略,提出了主动型下肢假肢设计和分类的通用控制框架,包括3个分层结构:上层控制器、中层控制器、底层控制器。其中,上层控制器感知运动意图;中层控制器将运动意图转换为预期的装置状态,用于底层控制器的跟踪参考;底层控制器通过反馈控制或者前馈控制计算出预期装置状态与当前装置状态的误差,驱动假肢执行这些命令,形成控制闭环。结果表明,该通用控制框架可完整阐释主动型下肢假肢的人—机—环境共融关系,明确了分层控制策略的层级任务,为未来主动型下肢假肢的发展提供了理论指导。     

新一代假肢

全世界每年因战争、交通事故、工伤和疾病而须截肢者有数百万人之多，然而其中还不到一半的在手术后有幸能安装假肢，而且即使装上了假肢，也会有行动仍然不便而且声响很大的缺点——原因很简单：目前制造假肢基本上仍沿用了40～50年代的老技术。     

新一代智能假肢

全世界每年因战争、交通事故、工伤和疾病而需截肢者有数百万之多，然而其中仅有不到三分之一的人在手术后有幸安装上假肢，而且即便装上了假肢，也会有行动不便而且声响很大的缺点。为了让截肢者安上更舒适的假肢，更好地恢复生活质量，世界各国的科学家们开展了多项研究。     

有“感觉”的智能仿生腿

随着社会的发展科技的进步,人类的假肢制作的材料及工艺较以往有了很大的提高。德国奥托博克公司最近研制的智能仿生腿,使假肢有了“感觉”。 这种智能仿生腿(C-leg)实际上是一个由电脑控制的液压人工膝关节系统。该系统在膝关节及脚部设有受力的传感装置,可将假肢的运动状态以每秒50次的采样频率,向电脑提供信     

日本开发出新型癌症诊断技术

日本京都大学等机构研究人员联合开发出一种能定位癌组织的新型癌症诊断技术,并希望首先将这项技术应用于乳腺癌的检查。     

立足精细化管理 全面构建全成本核算体系

精细化管理是一种新型管理理念,它注重“精”、“细”,提倡“细节决定成败”。把精细化管理应用到全成本核算工作中,是一次新的尝试。首先探讨了全成本核算实行精细化管理的具体做法,分析了实行全成本核算需要把握的4个关系和4个问题,然后阐述了实行全成本核算的初步成效,最后得出全成本核算精细化管理的4点启示,包括加强组织领导、整合核算机构、统一信息平台、强化绩效考评。     

Construction of a linkage map of the Rennell Island Tall coconut type (Cocos nucifera L.) and QTL analysis for yield characters.

AFLP and SSR DNA markers were used to construct a linkage map in the coconut (Cocos nucifera L.; 2n = 32) type Rennell Island Tall (RIT). A total of 227 markers were arranged into 16 linkage groups. The total genome length corresponded to 1971 cM for the RIT map, with 5-23 markers per linkage group. QTL analysis for yield characters in two consecutive sampling periods identified nine loci. Three and two QTLs were detected for number of bunches and one and three QTLs for number of nuts. The correlation of trait values between characters and evaluation periods is partially reflected in identical QTLs. The QTLs represent characters that are important in coconut breeding. The cosegregation of markers with these QTLs provides an opportunity for marker-assisted selection in coconut breeding programmes.     

A genetic map of Blumeria graminis based on functional genes, avirulence genes, and molecular markers

A genetic map of the powdery mildew fungus, Blumeria graminis f. sp. hordei, an obligate biotrophic pathogen of barley, is presented. The linkage analysis was conducted on 81 segregating haploid progeny isolates from a cross between 2 isolates differing in seven avirulence genes. A total of 359 loci were mapped, comprising 182 amplified fragment length polymorphism markers, 168 restriction fragment length polymorphism markers including 42 LTR-retrotransposon loci and 99 expressed sequence tags (ESTs), all the seven avirulence genes, and a marker closely linked to the mating type gene. The markers are distributed over 34 linkage groups covering a total of 2114 cM. Five avirulence genes were found to be linked and mapped in clusters of three and two, and two were unlinked. The Avr(a6) gene was found to be closely linked to markers suitable for a map-based cloning approach. A linkage between ESTs allowed us to demonstrate examples of synteny between genes in B. graminis and Neurospora crassa.     

A new endo-beta-galactosidase acting on the Gal beta 1-3Gal linkage of the proteoglycan linkage region.

A new type of endo-beta-galactosidase acting on the linkage region of peptidochondroitin sulfate was isolated from the mid-gut gland of the mollusk Patinopecten. The purification procedure included ammonium sulfate precipitation, Sephacryl S-200HR gel filtration, DEAE-Sephacel chromatography, and TSKgel Phenyl-5PW RP high performance liquid chromatography. The purified enzyme was free from exoglycosidases, sulfatases, and phosphatases. The specificity of the enzyme was as follows. 1) It acted on the internal galactoside linkage of sugar chains; 2) it specifically hydrolyzed the galactosylgalactose (Gal beta 1-3Gal) linkage, but not the galactosylxylose (Gal beta 1-4Xyl) linkage in the linkage region of peptidoglycans; 3) the enzyme activity was unaffected by the type of glycosaminoglycan, chondroitin sulfate, dermatan sulfate or heparan sulfate used as a substrate; 4) keratan sulfate and some oligosaccharides from glycolipid were not degraded by the enzyme. These properties of the endo-beta-galactosidase characterize it as a new endo-beta-galactosidase with unique specificity.     

Problems of the oncology outpatient: role of the liaison health visitor.

A survey by a liaison health visitor of outpatients attending an oncology department has identified and enumerated the principal problems with which she is confronted, and defined her role. The main medical symptoms of concern to the patient at home and needing attention by the liaison health visitor were anorexia, nausea, vomiting, and constipation: inadequate pain control due to poor drug compliance was also common. Other functions of the liaison health visitor include providing nursing aids and prostheses, support for bereaved relatives, and liaison with the community health care team.     

Structural design of the active site for covalent attachment of the heme to the protein matrix: studies on a thermostable cytochrome P450

The molecular basis of the post-translational modification involving covalent attachment of the heme with a glutamic acid observed in some enzymes of the CYP4 family of heme monooxygenases has been investigated using site-directed mutagenesis of CYP175A1 from Thermus thermophilus. Earlier studies of CYP4 as well as the G248E mutant of CYP101A1 showed covalent linkage of the heme to a conserved glutamic acid of helix I. We have introduced Glu/Asp at the Leu80 position in the β-turn of CYP175A1, on the basis of molecular modeling studies, to assess whether formation of such a covalent linkage is limited only to helix I or whether such modification may also take place with the residue that is spatially located at a position appropriate for activation by the heme peroxidase reaction. Tandem mass spectrometry analyses of the tryptic digest of the wild type and mutants of CYP175A1 were conducted to identify any heme-bound peptide. Tryptic digestion of the L80E mutant of CYP175A1 preincubated with H(2)O(2) showed formation of GLE(-heme)TDWGESWKEARK supporting covalent linkage of Glu80 with the heme in the mutant enzyme. No such heme-bound peptides were found if the sample was not preincubated in H(2)O(2), indicating no activation of the Glu by the heme peroxidase reaction, as proposed earlier. The wild type or L80D mutant of the enzyme did not give any heme-bound peptide. Thus, the results support the idea that covalent attachment of the heme to an amino acid in the protein matrix depends on the structural design of the active site.     

Ubiquitin and ubiquitin-modified proteins activate the Pseudomonas aeruginosa T3SS cytotoxin, ExoU

Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that possesses a type III secretion system (T3SS) critical for evading innate immunity and establishing acute infections in compromised patients. Our research has focused on the structure-activity relationships of ExoU, the most toxic and destructive type III effector produced by P. aeruginosa. ExoU possesses phospholipase activity, which is detectable in vitro only when a eukaryotic cofactor is provided with membrane substrates. We report here that a subpopulation of ubiquitylated yeast SOD1 and other ubiquitylated mammalian proteins activate ExoU. Phospholipase activity was detected using purified ubiquitin of various chain lengths and linkage types; however, free monoubiquitin is sufficient in a genetically engineered dual expression system. The use of ubiquitin by a bacterial enzyme as an activator is unprecedented and represents a new aspect in the manipulation of the eukaryotic ubiquitin system to facilitate bacterial replication and dissemination.     

Intérêt d'une double voie d'abord dans la chirurgie caverneuse complexe

Extensive cavernous body fibrosis is responsible for organic impotence when the lesions have advanced. Those fibrotic lesions can be caused by penile trauma, severe peyronie's disease, priapism (mostly post ICI) and rejection of a previously implanted prosthese. Sexual activity can be restored, mainly the erections, and is posiible with the insertion of penile prosthese. As a result of important anatomical changes, due to irregular indurations and retractions of the corpora, this surgery can be very difficult. The use of a double incisional approach (sub-coronal and perineal, degloving the penis out of its shaft through the perineal incision), allows, inspite of a potentially increased risk of infection, a total exposure making implantation and reconstruction much easier. The study of this limited series (from 1990 to 1996, 19 patients were operated with this procedure), allows to draw some preliminary conlusions about the pathology, the technique, the operatory (pre-, per-, and post-) precautions of this surgical procedure that treats serious erectile tissue fibrosis. Results are satisfactorily concerning recovery of penile rigidity as well as sexual activity.     

A comprehensive linkage map of the pig based on a wild pig - Large White intercross

A comprehensive linkage map, including 236 linked markers with a total sex-average map length of about 2300 cM, covering nearly all parts of the pig genome has been established. Linkage groups were assigned to all 18 autosomes, the X chromosome and the X/Y pseudoautosomal region. Several new gene assignments were made including the assignment of linkage group U1 (EAK-HPX) to chromosome 9. The linkage map includes 77 type I loci informative for comparative mapping and 72 in situ mapped markers physically anchoring the linkage groups on chromosomes. A highly significant heterogeneity in recombination rates between sexes was observed with a general tendency towards an excess of female recombination. The average ratio of female to male recombination was estimated at 1–4:1 but this parameter varied between chromosomes as well as between regions within chromosomes. An intriguing finding was that blood group loci were overrepresented at the distal ends of linkage groups.     

Identification of a New Locus for Autosomal Recessive Charcot–Marie–Tooth Disease with Focally Folded Myelin on Chromosome 11p15

Autosomal recessive Charcot–Marie–Tooth disease type 4B (CMT4B) is a demyelinating hereditary motor and sensory neuropathy characterized by abnormal folding of myelin sheaths. A locus for CMT4B has previously been mapped to chromosome 11q23 in a southern Italian pedigree. We initially excluded linkage in two Tunisian families with CMT4B to chromosome 11q23, demonstrating genetic heterogeneity within the CMT4B phenotype. Subsequently, using homozygosity mapping and linkage analysis in the largest Tunisian pedigree, we mapped a new locus to chromosome 11p15. A maximum two-point lod score of 6.05 was obtained with the marker D11S1329. Recombination events refined the CMT4B locus region to a 5.6-cM interval between markers D11S1331 and D11S4194. The second Tunisian CMT4B family was excluded from linkage to the new locus, demonstrating the existence of at least a third locus for the CMT4B phenotype.     

Cotransduction of his and trp loci by phage SV1 in Streptomyces venezuelae

Abstract A new tryptophan auxotroph of Streptomyces venezuelae was isolated by transduction of a histidine mutant to His⁺ after hydroxylamine mutagenesis of the transducing lysate. Cotransduction of at least two his genes and two trp genes was then demonstrated. One trp and two his markers were not cotransducible with this gene cluster, but the separate trp marker, trp -4, was cotransducible with a nic marker. These results are compatible with the distribution of similar markers on the conjugational linkage map of S. coelicolor A3(2), and so support the hypothesis of conservation of linkage relationships among putative homologous loci within the genus Streptomyces .