美国IM236—2489冷冻切片机的故障检修

故障现象：切片机通电后,压缩机不起动运转,但可听到轻微的嗡嗡声,热保护继电器几秒钟后动作、触点断开。如此反复动作,压缩机也不起动。　　原理分析：ＩＭ２３６－２４８９冰冻切片机的制冷系统设计独特,温度控制方式有别于其它制冷设备,而且冷冻台与仓内的制冷可分别控制。此冰冻切片机工作温度范围在－４０℃～＋４０℃之间。系统设有数字ＬＥＤ温度显示,通过转换开关,冷冻台与仓内的温度可分别显示,设定温度范围在－３９℃～＋３９℃。该机采用真空镀膜全封闭压缩机,二十四小时连续工作,压缩机的频繁动作会给压缩机造成很大…     

自制袖珍心音监听器及其应用

我们利用日本 Kenz-ES(DX)型电子听诊器胸端及国产莺歌牌晶体管中波段袖珍收音机改装成心音监听器,用于监听患者心音,简便易行,效果满意,现报告如下:制做及原理打开收音机外壳,从印刷电路板的     

Role of transforming growth factor P and bone morphogenetic protein composite on repair of bone defects

Bonerepairisacomplicatedprocess.Recentstudiesdemonstratedthatseveralgrowthfactorsplayanimportantroleinboneformation.Bonemorphogeneticproteins(BMPs)induceboneformationthroughstimulatingundifferentlatedmesenchymalproliferationanddifferentiationandinitiatingheterotopicboneformation.Transforminggrowthfactor5(TGF--0),mostabundantinquantityofthegrowthfactorsinthebody,stronglypromotestheembryogenesis,traumahealing,matrixsynthesis,osteoandosteochondralformationandboneremodeling.Ourpreviousexperimen…     

ECG—6511心电图机走纸马达的代换

ECG6511心电图机的走纸马达系直流6V电机，售价750元，价格较高且又一时难以买到。我们采用易购且又价廉的录音机走带电机（型号为EG530AD－6B的直流6V电机）代换，只花8元钱就解决了问题，效果很好，机器使用二年，至今工作正常。故障现象：开机后，按Start键，无论是25mm／s档还是50mm／s档，马达都不转。故障分析：由晶振X201产生32kHz的脉冲，经过Q204放大整形后，送到分频器IC209进行分频，从其⑤、①脚分别输出512Hz和256Hz的脉冲信号，再经速度控制转换门IC205D和IC205B送到相位比较器IC201的（14）脚，分别作为50mm／s和…     

Evaluation of transforming growth factor β and bone morphogenetic protein composite on healing of bone defects

ＥｖａｌｕａｔｉｏｎｏｆｔｒａｎｓｆｏｒｍｉｎｇｇｒｏｗｔｈｆａｃｔｏｒβａｎｄｂｏｎｅｍｏｒｐｈｏｇｅｎｅｔｉｃｐｒｏｔｅｉｎｃｏｍｐｏｓｉｔｅｏｎｈｅａｌｉｎｇｏｆｂｏｎｅｄｅｆｅｃｔｓＳｕｎＹｕｐｅｎｇ孙玉鹏，ＺｈａｎｇＷａｎｑｉｎｇ张皖清，Ｍ...     

INDUCTION OF OSTEOGENESIS BY BOVINE PLATELET TRANSFORMING GROWTH FACTOR-BETA (TGF-β) IN ADULT MOUSE FEMUR

TGF-β has been shown to be one of the most important regulators in chondrogenesis and osteogenesis. Daily subperiosteal injection of TGF-β, which was extracted and purified from bovine platelets, into adult mouse femur resulted in proliferation and differentiation of the mesenchymal cells, chondrogenesis, and endochondral osteogenesis. After cessation of the injection, the endochondral ossification occurred widely, resulting in replacement of the cartilage with new bone. These phenomena demonstrate that exogenous TGF-β stimulates mesenchymal proliferation and differentiation that occur in early fracture healing and suggest the possibility of clinical appli cation of TGF-β for fracture repair and bone transplantation.     

ROLE OF TRANSFORMING GROWTH FACTOR β （TGF-β）IN REPAIRING OF BONE DEFECTS

TGF-β is a multifunctlonal cytoklne that regulates many aspects of cellular function, including periosteal mesenchymal cell proliferation, differontlation. This experiment is to study its effects on bone defect repair. A rabbit radial bone defect model was used to evaluate the effect of TGF-β, which was extracted and purified from bovine blood platelets, on the healing of a large segmental osteoperiosteal defect. A1.5-centinaeter segmental defect was created in the mid upper part of the radial shaft of adult rabbits. The defect was filled with implant containing TGF-β that consisted of carrier and bovine TGF-β Limbs servedas controls received carrier alone. The defects were examined radiographically and histologically at 4, 8,12, 16 and 20 weeks after implantation. The results showed that in TGF-β implant group, the defect areasat 12 weeks post operation were bridged by uniform new bone and the cut ends of cortex could not be seen Fwhile in control group, the defects remained clear. Only a sraall amount of new bone formed as a cap onthe cut bone ends. In the experimental group, new lamellar and woven bone formed in continuity with thecut ends of the cortex. An entirely raedullar canal appears to be forming and contained normal-appearanclng marrow elements； while the control group displayed entirely fibrous tissue within the defect site. Remnants of the cancellous bone carrier were observed in the control specimen. These data demonstrate that exogenous TGF-β initiate osteogenesis and stimulate the bone defects repair in animal model.