苦参碱对豚鼠心肌电生理及机械特性的影响

目的　观察苦参碱对离体豚鼠右心室乳头状肌动作电位及收缩力 (Fc)的影响 ,以探讨其抗心律失常的作用机制。方法　采用标准玻璃微电极技术记录心肌细胞动作电位 ,肌力换能器同步记录心肌收缩力。结果　苦参碱 10、2 5、5 0 μmol·L-1可浓度依赖性地延长快反应动作电位(FAP)的复极 5 0 %时程 (APD50 )、复极 90 %时程 (APD90 )和有效不应期 (ERP) ,延长高钾除极组织胺及氯化钡诱发的慢反应动作电位 (SAP)的APD50 、APD90 ;但对FAP、SAP的动作电位振幅 (APA)、0期最大除极速率 (Vmax)及Fc无明显影响。结论　结果提示苦参碱对心肌细胞钠、钙离子通道无明显影响 ,其延长APD的作用可能是阻断心肌钾通道的结果。     

产业集群竞争力理论的演变

西方产业集群理论中对产业集群竞争力分析最为著名的有马歇尔的外部经济理论、克鲁格曼的新经济地理学理论和波特新竞争优势理论等。马歇尔是从新古典经济学的角度,通过研究工业组织这种生产要素,间接表明了企业为了追求外部规模经济而集聚。克鲁格曼的新经济地理学产业群模型从理论上证明了制造业(工业)活动倾向于空间集聚的一般性趋势,并阐明由于外在环境的限制,产业区集聚的空间格局可以是多样的,产业集聚空间格局的形成及锁定效应,是经济活动收益递增和运输成本相互作用的产物。迈克尔·波特从组织变革、价值链、经济效率和柔性方面所创造的竞争优势角度重新审视产业集群的形成机理和价值,并提出了国家竞争优势的“钻石模型”。产业集群竞争力理论随着产业集群的不断发展而相应地演变成系统的理论体系,并不断为全球化背景下的区域发展提供新的政策和管制思路。     

不同型号聚羧乙烯对口腔粘附缓释膜质量的比较

目的　比较不同型号生物粘附剂———聚羧乙烯对口腔粘附缓释膜质量的影响。方法　以中药复方溃宁为模型药,通过对给药系统的粘附力、体外释放速率等的测定进行评价。结果　3种膜剂的粘附力分别为CP934:6 6. 8±4 .5g/cm2 ;CP971 :5 5 . 9±4 .7g/cm2 ;CP974 :5 2 . 8±4 .4g/cm2 。体外释放速率(T50 )分别为CP934:2 4 0min ;CP971 :30 0min ;CP974 :1 0 0min。结论　不同型号的生物粘附剂聚羧乙烯对口腔粘附缓释膜的质量有显著影响;膜的粘附性CP934最大,CP974最小;释放速率CP974型最快,CP971型最慢。     

某部队官兵血清阴性脊柱关节病发病规律调查

目的 调查血清阴性脊柱关节病(SpA)在不同地区不同兵种部队中的发病及流行特点。方法 采用COPCORD询问表,对内陆平原地区、南疆干旱地区、北疆寒冷高原地区及沿海潮湿地区,包括陆、海、空三军共21750人进行四级调查,初步诊断病例行X线及HLA-B27检测。结果 SpA患病率4.87‰,其中强直性脊柱炎(AS)患病率2.11‰,反应性关节炎(ReA)患病率0.276‰,未分化脊柱关节病(uSpA)患病率2.39‰,AS、uSpA在海军中患病率高于其他兵种。AS在高原寒冷地区及沿海潮湿地区的患病率高于干旱地区及内陆地区,uSpA在沿海潮湿地区的患病率高于干旱地区及内陆地区。结论 AS、uSpA在部队的患病率接近普通人群,在海军中患病率高于其他兵种,在高原寒冷及潮湿环境地区部队的患病率增高。     

Biomechanics of occlusion – implications for oral rehabilitation

The dental occlusion is an important aspect of clinical dentistry; there are diverse functional demands ranging from highly precise tooth contacts to large crushing forces. Further, there are dogmatic, passionate and often diverging views on the relationship between the dental occlusion and various diseases and disorders including temporomandibular disorders, non‐carious cervical lesions and tooth movement. This study provides an overview of the biomechanics of the masticatory system in the context of the dental occlusion's role in function. It explores the adaptation and precision of dental occlusion, its role in bite force, jaw movement, masticatory performance and its influence on the oro‐facial musculoskeletal system. Biomechanics helps us better understand the structure and function of biological systems and consequently an understanding of the forces on, and displacements of, the dental occlusion. Biomechanics provides insight into the relationships between the dentition, jaws, temporomandibular joints, and muscles. Direct measurements of tooth contacts and forces are difficult, and biomechanical models have been developed to better understand the relationship between the occlusion and function. Importantly, biomechanical research will provide knowledge to help correct clinical misperceptions and inform better patient care. The masticatory system demonstrates a remarkable ability to adapt to a changing biomechanical environment and changes to the dental occlusion or other components of the musculoskeletal system tend to be well tolerated.     

Quantitative examination of isometric tongue protrusion forces in children with oro‐facial dysfunctions or myofunctional disorders

Oro‐facial dysfunctions (OFD) or oro‐facial myofunctional disorders in children lead to severe problems in teeth and jaw position, articulation, chewing and swallowing. The forces of the tongue, the central muscle for articulation, chewing and swallowing are focused on in several studies. In this examination, isometric tongue protrusion forces (TPF) of children with OFD and controls were compared. Thirty participants with OFD and 30 controls were presented a target force level as a straight line on a monitor that they were supposed to match by generating an isometric tongue force for different target levels (0.25 N and 0.5 N). Correlations of the severity of OFD (symptom score) with the capacities of the TPF 0.25 N and 0.5 N were calculated. Statistical differences were obvious in TPF variability and the accuracy, depending on the weight. Tongue contact time, expressed as per cent (TCT, total contact: 100%), was significantly lower in children with OFD (P = .005). Mean and median TPF was not different between groups. The predictive value of TPF for OFD revealed a level of 58.6% for TPF 0.25 N and 74.5% for TPF 0.5 N. Correlations of the severity of OFD were seen for some parameters. Subjects with OFD show significantly lower competencies in accuracy and endurance of tongue protrusion forces. This may have a high impact on phenotyping children with OFD and influence therapeutical approaches.     

Ultrathin films of charged polysaccharides assembled alternately with linear polyions

As a means of preparation of biocompatible molecular surfaces, an alternate assembly of charged polysaccharides and oppositely-charged synthetic polymers was conducted. Cationic chitosan was assembled alternately with anionic poly(sodium styrenesulfonate) (PSS) at pH 4. Regular film growth and its dependence on ionic strength were detected by the quartz crystal microbalance (QCM) method. Averaged film thicknesses for the chitosanCPSS layer were 15, 31, 46, and 69 A° , respectively, when 0, 0.25, 0.5, and 1 M of NaCl was contained in aqueous chitosan. Adsorption of chitosan did not reach saturation in 20 min at 0 M NaCl, while the adsorption became saturated within 6 min with 0.25 M NaCl. Anionic sodium chondroitin sulfate was also assembled in alternation with cationic poly(dimethyldiallylammonium chloride) (PDDA) at pH 6.5. The adsorption of chondroitin sulfate was less sensitive to ionic strength. Surface morphology of chitosan–PSS films was investigated by non-contact atomic force microscopy (AFM) observation. Maximum height difference and Ra value for a 1000 × 1000 nm area were 11 and 0.69 nm, respectively, indicating the formation of a molecularly flat surface by alternate layer-by-layer adsorption.     

Sound side joint contact forces in below knee amputee gait with an ESAR prosthetic foot

The incidence of knee and hip joint osteoarthritis in subjects with below knee amputation (BK) appears significantly higher compared to unimpaired subjects, especially in the intact side. However, it is controversial if constant higher loads on the sound side are one of the major factors for an increased osteoarthritis (OA) incidence in subjects with BK, beside other risk factors, e.g. with respect to metabolism. The aim wasto investigate joint contact forces (JCF) calculated by a musculoskeletal model in the intact side and to compare it with those of unimpaired subjects and to further elucidate in how far increased knee JCF are associated with increased frontal plane knee moments. A group of seven subjects with BK amputation and a group of ten unimpaired subjects were recruited for this study. Gait data were measured by 3D motion capture and force plates. OpenSim software was applied to calculate JCF. Maximum joint angles, ground reaction forces, and moments as well as time distance parameters were determined and compared between groups showing no significant differences, with some JCF components of knee and hip even being slightly smaller in subjects with BK compared to the reference group. This positive finding may be due to the selected ESAR foot. However, other beneficial factors may also have influenced this positive result such as the general good health status of the subjects or the thorough and proper fitting and alignment of the prosthesis.     

Disorders characterized by predominant or exclusive dermal inflammation

Some cutaneous inflammatory disorders are typified by a predominant or exclusive localization in the dermis. They can be further subdivided by the principal cell types into lymphocytic, neutrophilic, and eosinophilic infiltrates, and mixtures of them are also seen in a proportion of cases. This review considers such conditions. Included among the lymphoid lesions are viral exanthems, pigmented purpuras, gyrate erythemas, polymorphous light eruption, lupus tumidus, and cutaneous lymphoid hyperplasia. Neutrophilic infiltrates are represented by infections, Sweet syndrome, pyoderma gangrenosum, and hidradenitis suppurativa, as well as a group of so-called “autoinflammatory” dermatitides comprising polymorphonuclear leukocytes. Eosinophil-dominated lesions include arthropod bite reactions, cutaneous parasitic infestations, the urticarial phase of bullous pemphigoid, Wells syndrome (eosinophilic cellulitis), hypereosinophilic syndrome, and Churg-Strauss disease. In other conditions, eosinophils are admixed with neutrophils in the corium, with or without small-vessel vasculitis. Exemplary disorders with those patterns include drug eruptions, chronic idiopathic urticaria, urticarial vasculitis, granuloma faciale, and Schnitzler syndrome (chronic urticarial with a monoclonal gammopathy).