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Objective To study the effect of non-self-similar hierarchy on fracture mechanical properties and crack propagation of the biocomposite. Methods The numerical models were established by using ABAQUS, and the stiffness and crack initiation and propagation in the biocomposite with the inclination angles between the axis of the prism and mineralized collagen fibrils θ=0°,20°,40°,60°,80° were simulated by extended finite element method. Results The inclination angle θ had limited influences on biocomposite stiffness at θ≤40°, while biocomposite stiffness decreased with θ at θ>40°. The ultimate tensile strain also increased at θ>40°. Asymmetry in the crack was also found during propagation of matrix surrounded-enhanced phases at θ>0°. The crack propagatation on one side of the long axis of the mineral crystal was relatively easier than that on the other side at θ>0°. Conclusions The non-uniform distributions of cracks were found in biological hard tissues arisen from the non-self-similar hierarchy. The non-uniform crystal arrangement in the biocomposite would result in local damage rather than catastrophic fracture. The findings of this study can provide theoretical support for material design.
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Objective To study the effect of microscopic observation drug susceptibility assay (MODS)for testing Mycobacteri-um tuberculosis in sputum ,and to evaluate its clinical value .Methods A total of 150 sputum samples were collected from patients with pulmonary tuberculosis ,and Mycobacterium tuberculosis were detected by Lowenstein-Jensen (L-J) method and MODS ,and compared the results of the two methods .Results The concordance rates of the test results of sputum sample between MODS and L-J was 77 .8% .The sensitivity and specificity of MODS were 93 .3% and 70 .0% ,positive predictive value (PPV ) was 60 .8% , negative predictive value (NPV) was 95 .4% ,as well as accuracy by MODS was 77 .8% .Conclusion MODS assay could be used as a rapid tuberculosis detection method ,with rapid ,sensitive ,simple ,and other advantages .
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Complications of vascular access are main component of vascular complication in percutaneous cardiovascular intervention.The common complications of femoral access may include hemorrhage and hematoma at access site,vasovagal reflex,pseudoaneurysm,arteriovenous fistula,retroperitoneal hematoma and deep venous thrombosis.The common complications of radial access may include radial artery spasm,radial artery occlusion,vascular injuries or hematoma at forearm and other sites,and osteofascial compartment syndrome.The common complications of ulnar and brachial accesses may include hemorrhage and hematoma at access site,upper limb and hand ischemia,and nerve injuries.Effective prevention and treatment of vascular access complications are key steps to minimize the incidence and hazards of vascular complications in percutaneous cardiovascular intervention.
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Objective To investigate the association between renin-like activity (RA) and angiotensin Ⅱ (AⅡ) and the ovarian hyperstimulation syndrome (OHSS). Methods Blood samples were taken from 42 patients undergoing in vitro fertilization (IVF). According to the ovarian stimulating response, the patients were divided into 4 groups: group Ⅰ, low responders, 7 cases; group Ⅱ, moderate responders, 8 cases; group Ⅲa high responders without using albumin, 7 cases, group Ⅲb, high responders with albumin, 10 cases; group Ⅳ, severe and moderate OHSS, 10 cases. 5 patients for intrauterin insemination with natural cycle as control. Follicular fluid (FF) was collected at oocyte retrieval from 28 IVF patients (including 7 OHSS patients). Fluid from ascites and hydrothorax was obtained from 3 OHSS patients, and peritoneal fluid obtained from 5 infertility patients by laparoscopy and ascitic fluid obtained from 6 ovarian carcinoma patients served as control. RA and AⅡ levels were measured by radioimmunoassay. Results plasma RA and AⅡ levels at mid-luteal phase from OHSS patients [(19.9?19.0)?g?L -1 ?h -1 and (397.0?378.2) ng/L] were significantly higher than those from the other patients ( P
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By studying the physician-related factors in physicianpatient relationship,authors put forwards that excellent medical skill,good medical ethics,favorable communication ability,and adequate knowledge on relevant legal regulations are four key points to handle the physician-patient relationship harmoniously.This article will supply reference from the above aspects for the all-around quality-based education for medical students.
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AIM: To explore the effects of tumor necrosis factor-? (TNF-?) on inducible nitric oxide synthase (iNOS)-nitric oxide (NO) system activity in arginine vasopressin (AVP)-induced rat cardiac fibroblasts (CFs). METHODS: CFs were isolated by trypsin digestion method. Nitrate reductase method, spectrophotometry and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect NO contents, NOS activity and iNOS mRNA expression, respectively. RESULTS: AVP significantly increased iNOS mRNA expression, NOS activity and NO contents in CFs. Combined with AVP, TNF-? enhanced the effects of AVP on iNOS-NO system activity in a concentration-dependent manner. However, if the concentration of TNF-? was too high, the iNOS-NO system activity did not increase accordingly, but slightly decreased instead. CONCLUSION: TNF-? stimulates iNOS-NO system activity in coordination with AVP in CFs. The enhancement of NO contents inhibits ventricular remodeling induced by AVP and TNF-?. [
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Objective To explore the effect of arginine vasopressin(AVP) on proliferation and nitric oxide(NO) synthesis in rat cardiac fibroblasts(CFs). Methods CFs were isolated by trypsin digestion method. The effect of AVP on proliferation and NO synthesis were measured by MTT technique and nitric acid reductase method respectively. Results The MTT OD values of CFs increased in a concentration-dependent manner with the rising of the concentration of AVP and in a time-dependent manner with the prolongation of the culture time. For example, the MTT OD values of 10 -6 mol/L AVP group were higher than those of the control, and the MTT OD values of CFs cultured for 36h were significantly higher than those cultured for 6h when intervened with 10 -7 mol/L AVP. The content of NO of CFs displayed the same change as the MTT OD values. The contents of NO in 10 -7 mol/L and 10 -6 mol/L AVP groups were statistically higher than those of the contral group, 10 -9 mol/L AVP group and 10 -8 mol/L AVP group. The NO contents of CFs cultured for 24h and 36h were significantly higher than those cultured for 6h and 12h. Conclusion AVP can stimulate the proliferation of CFs and the synthesis of NO in neonatal rat. The enhancement of NO contents would inhibit CFs proliferation and myocardial fibrosis induced by AVP.