BACKGROUND: Authors' previous studies showed that U-shaped plate could give continuously pressure to broken ends of fractured bone and make the fractured region in an optimal environment and promote union of fracture.OBJECTIVE: To discuss the loading ability of modified U-shaped plate.DESIGN, TIME AND SETTING: The single sample experiment was performed at the Laboratory of Materials Mechanics, Central South University from December 1990 to April 2001.MATERIALS: Plain bone plate is provided by Jiangsu Jinlu, China. AO plate and dynamic compression plate are purchased from MATHYS, Switzerland. U-shaped plate is a modified plate with a U-shaped arm in the middle of a common plate (Patent number 012497304).METHODS: We measured the mechanics of experimental mode to understand the compressing and distorting ability, m test theoretic calculation and to compare with common plate, AO plate and dynamic compression plate.MAIN OUTCOME MEASURES: Bending ability and distorting ability.RESULTS: Compared with the same usage of AO-Plate and dynamic compression plate at sagittal face, the bending ability of U-shaped plate could increase respectively by 107.5% and 21.5%, and the distorting ability increase respectively by 406% and 58%. Distorting ability increased by 31.9%, compared with limited contact dynamic compress plate (LC-DCP).CONCLUSION: Modified U-shaped plate is an eligible plate of enough strength and rigidity, compared with common AO plate and compress plate.

Objective To observe pre-syncopal limited tolerance and cardiovascular responses to head-up tilt combined with lower body negative pressure (HUT/LBNP) following exposure to head-down tilt (HDT, -1 Gz). Method Exposures to HUT/LBNP (-60 mmHg) in control session (without preceding 30 s -1 Gz treatment) and in simulated push-pull effect (PPE) session (with preceding 30 s -1 Gz treatment) were performed in 8 healthy adults. The changes of hemodynamic parameters were monitored by electrical impedance instrument during the experiments. Result The mean endurance time in presyncopal symptom limited HUT/LBNP in control session and in simulated PPE session were 8.4±2.1 min and 4.5±2.4 min, respectively, the two means were significantly different (P< 0.01). In simulated PPE session, as compared with baseline, heart rate (HR) during HDT was significantly lowered (P<0.01), while stroke volume (SV) and cardiac output (CO) were increased significantly (P<0.01). During HUT/LBNP, the increased percentage (relative to baseline) of HR in PPE session was lower than these in control session (P<0.05); the decreased percentages of SV and CO during HUT/LBNP in PPE session were both higher than those in control session (P<0.05). During HUT/LBNP, arterial pulse pressure (PP) of control session was significantly decreased than the value of baseline value (P<0.05); Total peripheral resistance (TPR) of PPE session was significantly increased than baseline value (P<0.05). Conclusion Tolerance time before the appearance of presyncopal symptoms during HUT/LBNP decreases and cardiovascular responses to HUT/LBNP are impaired, preceding exposure to HDT.

The article described the characteristics of research teaching and try to adopt a different research teaching methods based on the characteristics of the contents of each chapter of aerospace biodynamics to enhance the effectiveness of military medicine lesson and cultivate innovative thinking ability of students in military schools.

Objective To clone the fragment of hepatitis C virus(HCV) core gene and express it in E.coli.Methods The fragment of HCV core gene(approximate 366bp) was amplified by PCR and inserted into the pMD18-T vector.The cloned HCV core gene,which was confirmed by the digestion with EcoRⅠ/BamHⅠ,was subcloned into the expression vector pBV220 to construct recombinant plasmid pBV220/HCV-C.The expressed gene product was identified by SDS-PAGE and Western blotting.Results The fragment of HCV core gene was expressed successfully after temperature induction and a protein of 14 000 u was resulted.Conclusion Expression of the HCV-C gene in E.coli was achieved,which may be helpful for further studies on characterizations of HCV-C gene.

Objective To investigate the role of spinal cord chemokine CXC ligand13(CXCL13) in the formation of rat bone cancer pain(BCP).Methods Twenty healthy female SD rats weighing 160-200 g were divided into four groups(n=5):sham operation group(S),BCP group(BP),small interference RNA(siRNA) negative control(NC-siRNA) group (NC) and CXCL13-siRNA group(CS).Normal saline was given by tibial medullary cavity injection in the S group.The tibial BCP model was established by tibial medullary cavity injection of equivalent Walker-256 breast cancer cells in the group BP,NC and CS.NC-siRNA lentivirus and CXCL13-siRNA lentivirus were injected intrathecally in the group NC and CS respectively.The mechanical pain threshold was measured on 1 d before model construction and on postoperative 7,9,14,21 d.The rats were killed after pain threshold measurement.The spinal cord and tibial tissue were taken.The co-expression of spinal CXCL13,microglia specific marker Iba-1 and neuron specific neucleoprotein NeuN was determined by using the immunofluorescence double standard staining,and expressions of CXCL13 and ionized calcium binding adaptor molecule-1 (Iba-1) protein and mRNA in spinal cord were detected by Western blot and RT-PCR;the HE staining microscopy was adopted to observe the tibial bone structure destroy situation.Results Compared with group S,the mechanical pain threshold in theBP group and NC group was decreased on 7-21 d after inoculation,CXCL13 expression in neuron was significantly increased and microglia was obviously activated,the expression of CXCL13 and Iba-1 protein and mRNA was significantly elevated (P＜0.05);compared with the NC group,the mechanical pain threshold on 9-21 d after model construction in the CS group was significantly increased,CXCL13 expression in neurons was significantly decreased,microglia activation was decreased and expression of CXCL13 and Iba-1 protein and mRNA was significantly decreased(P＜0.05);HE staining showed that the model groups appeared the tumor growth in bone marrow cavity,moreover which was eroded outwards and destroyed bone cortex,but no abnormality was found in the S group.Conclusion Spinal cord CXCL13 is involved in the BCP formation in rats by activating microglia.

In order to effectively increase capacity of Cu2+ absorption by Penicillium from Cu2+-containing aqueous solution and to study the mechanisms of absorption, effects of eight pre-treatment methods on Cu2+ absorption of Penicillium janthinellum strain GXCR were compared. The results showed that the efficiency of Cu2+ absorption obviously increased through pre-treatment by homogenization, homogenization-basification (NaOH), oven dry (80 degrees C), homogenization-salinification (NaCl), homogenization-detergent and homogenization-polarization (C2H6SO), but significantly decreased after acidification pretreatment with H2SO4. In comparison with the previous reports, the pretreatment in a homogenization-NaOH way could more efficiently enhance the Cu2+ absorption capacity of this fungus. Homogenization-basification (0.5 mol/L NaOH) increased Cu2+ biosorption by 47.95%. The Cu2+ absorption of the mycelia treated by homogenization-basification followed Langmuir isotherm equation, suggesting a surface absorption process. After four cycles of absorption-desorption, mycelia pretreated by homogenization-alkalization still had 70.82% of Cu2+ biosorption efficiency. Infrared reflectance analysis indicated that alkalization treatment made marked effects on molecular groups of C-H, C=O, and C=O in COOH on the mycelial surfaces, and -OH was a key Cu2+-binding group. It is therefore suggested that the Cu2+ absorption by the GXCR is likely to be a chemical absorption process through Cu2+ binding with -OH group on the mycelia.
Adsorption ; Biodegradation, Environmental ; Copper ; metabolism ; Penicillium ; metabolism ; Physical Phenomena ; Sodium Hydroxide ; chemistry ; Waste Disposal, Fluid ; methods ; Water Pollutants, Chemical ; metabolism