Relationships among magnetic resonance imaging, histological findings, and IGF-I in steroid-induced osteonecrosis of the femoral head in rabbits

Objective: To study the relationships among magnetic resonance imaging (MRI), histological findings, and insulin-like growth factor-I (IGF-I) in steroid-induced osteonecrosis of the femoral head in rabbits. Methods: Thirty rabbits were randomly divided into experimental Group A (n=15) and control Group B (n=15). The 7.5 mg/kg (2 ml) ofdexamethasone (DEX)and physiological saline (2 ml) were injected into the fight gluteus medius muscle twice at one-week intervals in animals of Groups A and B, respectively. At 4, 8 and 16 weeks after obtaining an MRI, the rabbits were sacrificed and the femoral head from one side was removed for histological study of lacunae empty of osteocytes, subchondral vessels, and size of fat cells under microscopy, and the femoral head from the other side was removed for enzyme-linked immunoadsorbent assay (ELISA) for IGF-I.Results: At 4, 8 and 16 weeks after treatment, no necrotic lesions were detected in Group B, while they were detected in Group A.Light microscopy revealed that the fat cells of the marrow cavity were enlarged, subchondral vessels were evidently decreased,and empty bone lacunae were clearly increased. The IGF-I levels in Group A were significantly higher than those in Group B. At 8 weeks after the DEX injection, the MRI of all 20 femora showed an inhomogeneous, low signal intensity area in the femoral head,and at 16 weeks, the findings of all 10 femora showed a specific "line-like sign". The MRI findings of all femora in Group B were normal. Conclusion: MRI is a highly sensitive means of diagnosing early experimental osteonecrosis of the femoral head. However, the abnormal marrow tissues appeared later than 4 weeks when the expression of IGF-I increased. This reparative factor has an early and important role in response to steroid-induced osteonecrosis of the femoral head, and provides a theoretical foundation for understanding the pathology and designing new therapies.     

强化公共产品意识 推进教育事业发展

按照公共经济学的理论,我们可以依据是否具有完全非竞争性和非排他性这两大特征,将公共产品分为两类,即纯公共产品和准公共产品。教育是一种公共产品,根据其服务和提供的不同特点,我们把义务教育归为纯公共产品,把非义务教育归为准公共产品。为此,我们必须树立和强化教育的公共产品意识,明确政府职责,坚持以政府投入为主,鼓励和扶持社会的多元化投入,推动教育事业健康发展,努力办好让人民群众满意的教育。     

深化实习改革加强实践教学

文章论述了金工实习由原来的仅有车、钳、铸、焊等工种的传统数学模式向现代制造基础实践教学的方向发展,论述了金工实习的内容与方式的改进,教学实践,提出教改新思路.     

Parental Authoritarian Control and Cognitive Complexity

Studies on the conceptual system proposed by Harvey et aJ (1961) suggested that the concrete mode of cognitive functioning is associated with certain developmental factors such as restricted exploration of the environment, overcontrol by parents, avoidance of uncertainty, conformity to external superimposed norms, and discouragement of independence, etc. Using the framework of Harvey, Schroder et al (1967) specified two types of training methods, one of which he called the deductive method. Parents adopting this method provide the child with ready made and fixed rules. The child is taught to avoid uncertainty by looking externally for rules. The variety of perceptions and responses available to the child is highly restricted. The environment is so structured that it is unrealistically oversimplified. Schroder et al believe that this type of training method would bring out a cognitive structure which is characterized by compartmentalization and inability to think in terms of degrees or relativeness.     

谢榛诗学批评的系统架构

谢榛，《明史》卷九十九．卷二八七，列传一七五皆有记载．言李攀龙、王世贞辈“称诗指要，实自榛发也。”其有《四溟山人集》二十卷，诗四卷并《诗家直说》四卷留世，本试图通过《诗家直说》来阐述谢榛对诗歌的发生、本质、艺术构思、鉴赏等问题的系统观点，以期勾勒出谢’榛的诗学批评架构。     

机动车驾驶员疲劳检测系统的研究现状及发展趋势

文章首先介绍了国内外对机动车驾驶员疲劳检测系统的研究现状，阐述了驾驶员疲劳检测的关键技术在于驾驶员疲劳机理和数学模型、驾驶员疲劳检测方法和评价体系、驾驶员疲劳检测系统的商品化等，最后总结了驾驶员疲劳检测系统良好的应用前景和展望了其研究发展趋势。     

军械装备包装改革综合技术研究

介绍国内外军械装备包装发展现状，阐述了军械装备包装改革综合技术研究的重大意义，提出了军械装备包装技术改进的方法和军械装备包装管理改革的措施，探讨了军械装备包装改革今后努力方向。     

土地评估机构资质的立法冲突和解决对策

关于土地评估机构资质的行政立法矛盾已持续多年，给国企改制等市场化趋向产生了延时、不确定和偏失公正等影响，其引发的诉讼还给司法部门带来了抉择难题：这种行政立法矛盾的产生很大程序上与部门利益有关。全文探讨了最终解决矛盾的对策及过渡期的衔接方法。     

略谈新世纪教育的选择

根据新世纪教育发展的走势和要求 ,分析了当代教育的必然选择 ,并就科学教育与人文教育融合、人才培养模式进行了探讨     

Inverstigation on the Separated Turbulent Flow Field in Dual Rectangular Jets

In the present paper,the flow field of dual rectangular jets was numerically simulated by solving the full Reynolds averaged Navier-Stokes equations,where the RNG κ-ε model and the finite volume method were used.The flow structure in dual rectangular jets and the effects of the velocity were investigated.The numerical results agree qualitatively with the experimental data.