BACKGROUND: With the continuous development of materials science, magnesium alloy vascular stent materials have become a hot research. Because of the mechanical properties and biocompatibility of commercial magnesium alloy, it is difficult to meet the requirements of vascular stents. Therefore, effective measures to improve the sten's surface properties and comprehensive performance become the focus of research.OBJECTIVE: To study the histology and surface modification of vascular stents in rapidly solidified Mg-Zn-Y-Nd alloy.Methods: The low-zinc Mg-2Zn-0.2Y alloy with good mechanical properties and corrosion resistance was selected as the basic material, and Nd and Zn elements were added to refine the alloy stents. After the microstructure of the stent was extruded, the surface modification of the stent was completed and the comprehensive properties of the alloy were improved. The new magnesium alloy for the stent was obtained and the stent surface was modified. The metallographic microstructure, scanning electron microscopy and radiological analysis were used to study the microstructure and mechanical properties of the prepared stents. The mechanical properties of the stents were investigated by hardness and tensile tests.RESULTS AND CONCLUSION: (1) Metallographic microstructure results showed that: when Y elements were not added, the second phase of the magnesium alloy was rod-shaped, and there were a few granules embedded in the matrix. After addition of 0.5% Y elements, in the second phase of the magnesium alloy stent, the shafts were significantly reduced in number, and granules were increased in number and evenly distributed in the body. After the addition of 1% Y,the second phase number increased, a large number of dendrites were visible in the grains, and discontinuous rods existed in the second phase. After the addition of 1.5% Y, the second phase was rod-shaped, with mixture of large and local dendrites in the alloy. (2) X-ray diffraction test results: Mn-Zn-0.5Nd alloy and Mn-Zn-1.0Nd alloy contained the same phases (Mg4Zn7 and (Nd, Y) 2Zn17 phase). When the concentration of Nd increased to 1%, the new MgZn2 phase appeared in the alloy. (3) SEM & EDS test results of modified magnesium alloy showed that after magnesium alloy modification, the second phase contained Zn, Nd and Y elements, and their contents were very close. EDS analysis showed that after the addition of Zr elements, the level of Zn elements in the lamellar second phase decreased significantly, and the level of Nd and Y elements increased, indicating a more stable performance. (4) Micro-hardness test results showed that with the increasing of the content of magnesium alloy, the alloy microhardness increased. (5)Tensile test results showed that the tensile strength and yield strength of the Mg-Zn-Y-0.5Nd-Zr stent were significantly higher than those of Mg-Zn-Y-0.5Nd, Mg-Zn-Y-1.0Nd,Mg-Zn-Y-1.0Nd-Zr stents (P < 0.05); and the elongation at break of Mg-Zn-Y-0.5Nd-Zr and Mg-Zn-Y-1.0Nd-Zr stents was significantly higher than that of Mg-Zn-Y-1.0Nd and Mg-Zn-Y-0.5Nd stents (P < 0.05). To conclude, with Mg-2Zn-0.2Y as core materials, the material modification could be completed by the addition of Nd and Zn elements, and the surface modification could be implemented by extruding and refining the stent microstructure. The modified material has excellent properties.

Objective To investigate the adrenal histopathology damage in critically ill non-survival children,and the incidence of adrenal damage,and to explore the risk factors for the adrenal hemorrhage and necrosis in critically ill children.Methods A total of 141 critically ill non-survival children was admitted in this study in Hunan Children's Hospital from January 1,2005 to December 30,2012.Clinical data in children were systematically collected,including age,sex,sodium,potassium,blood gas analysis,liver and kidney function,blood clotting function,etiology,treatment and pediatric clinical illness score (PCIS) or neonatal critical illness score (NCIS),and pathological data.All data were analyzed by SPSS 18.0.Results Logistic regression analysis showed the factors of adrenal hemorrhage and necrosis of critically ill non-survival children were sepsis,PCIS score ＜ 80 critically ill children are risk factors for adrenal hemorrhage necrosis (P ＜ 0.05),ORwas 3.659 (95％ CI:1.344-9.965),and 2.325 (95％ CI:1.028 -5.258).Intravenous corticosteroids were protective factors for critically ill non-survival children with adrenal hemorrhage necrosis (P ＜ 0.05),and ORwas 0.377 (95％ CI:0.163-0.875).Conclusions There were two significant risk factors of adrenal hemorrhage and necrosis:sepsis and critical illness score less than 80 points.Intravenous corticosteroid is a protective factor in critically ill children.

Background Whether serum uric acid are related with ischemic stroke in essential hypertension (EH) is controversial. Objective To delineate the relationship between serum uric acid and ischemic stroke in EH. Methods A retrospective study was conducted in a cohort of 729 EH patients. Patients were classified into four groups according to serum uric acid level. The odds ratio for ischemic stroke was calculated with the lowest quartile as the reference. Results The prevalence of ischemic stroke in EH with quartile 4 of uric acid was higher than that in EH with quartile 1(37.9% vs 17.6%,P

Objective To investigate the effect of metabolic syndrome(MS) on the atrial fibrillation(AF) in patients with essential hypertension(EH).Methods A cross-sectional study was conducted in a cohort of 1810 hospitalization essential hypertension patients,which were divided into EH+non MS group(n=1155) and EH+MS group(n=655) according to MS criteria.Results Incidence of AF in EH+MS group was higher than that in EH+non MS group(14.4% vs 8.3%,P

Objective To investigate the expression of apoptosis-related neuclosome assembly protein-1(NAP-1) gene in related brain region of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP) treated mice and beta-amyloid treated rats. Methods The animal models with central nervous system degeneration were established by consecutive administration of MPTP to C57BL mice and injection of beta-amyloid to brain ventricular of SD rats. The RNA in striatum and substantia nigra of mice and the RNA in cortex and hippocampus of rats were extracted. The levels of NAP-1 mRNA in these samples were estimated by RT-PCR. Results For mice, the expression of NAP-1 were decreased after MPTP treatment in substantia nigra, while its expression showed no significant change in striatum. In contrast, no effect on NAP-1 gene expression by beta-amyloid injection can be detected in cortex and hippocampus of rats. Conclusions The apoptosis of dopaminergic neurons in nigrostriatal pathway after MPTP treatment may be related to the expression of NAP-1 gene. But the mechanism of neurodegeneration after beta-amyloid injection in rats may be different.

AIM: To obtain differentially expressed cDNA fragments in the cerebellum of rats and screen unknown expressed sequence tag (EST). METHODS: Suppression subtractive hybridization (SSH) was carried out, in which the cDNA fragments of cerebellum were taken as "tester" and correspondingly that of cerebrum and brain stem as "driver". The homogeneous sequences between the tester and driver were excluded and the rare sequences in cerebellum were enriched by SSH. The differentially expressed cDNA fragments were further cloned for the construction of subtracted cDNA libraries and sequencing. RESULTS: 32 clones were selected and 34 cDNA fragments were sequenced. 8 of 32 were proved to be true positive with reverse Northern assay, 13 of 34 fragments were identified to be new cDNA fragment and given the gene sequence numbers by GenBank (AW288461-AW288474). CONCLUSION: SSH is very useful method for screening differentially expressed genes. Our data may be helpful to understand the molecular mechanism of brain function.

Objective:To explore the role of DKK-1 andβ-catenin expressions in progression of proximal gastric cancer (PGC). Methods:The expression of DKK-1 andβ-catenin in 61 cases with PGC and para-neoplastic tissues and 20 cases with normal gastric mucosa was detected by immunohistochemistry. The related clinical significance in the cases was studied. Results:The positive expression rate of DKK-1 and the abnormal expression rate ofβ-catenin in the tissue sections of PGC were 34.4%(21/61) and 68.9%(42/61), respectively. The positive expression rate of DKK-1 and the abnormal expression rate ofβ-catenin in para-carcinoma tissues were 8.2%(5/61) and 6.6%(4/61) , respectively. The positive expression rate of DKK-1 and the abnormal expression rate ofβ-catenin in normal gastric mucosa were 15.0%(3/20) and 10.0%(2/20), respectively. The expression rate was significantly higher in PGC than that in the other tissues (P<0.05). The expression of DKK-1 was positively related to that ofβ-catenin in PGC (r=0.454, P<0.05), but not in the others. Conclusion:Higher expressions of DKK-1 and the abnormal expression ofβ-catenin are closely related to the occurrence of PGC.

Objective To evaluate the mode of referral by response time for inter-hospital transfer of critically ill pediatric patients,and subsequently some measures taken for minimizing the response time in referral process.Methods A total of 9231 patients (≤14 years) transferred from primary hospital were included in a cross-section study.Information about age,sex,referral radius,the seasonal variation for inter-hospital transport of critically ill pediatric patients,time of referral telephone call and response time were collected.All computations were performed using the Statistic Package for Social Sciences for Windows version 18.0.Differences between groups were assessed by x2 tests or Wilcoxon test or Kruskal-Wallis for categorical data.Results Among all critically ill pediatric patients for the inter-hospital transfer,male to female ratio was 2.24:1,and the majority of patients were neonates and infants.Median retrieval mobilization time was 30 min (interquartile range,20-50 min).This study has demonstrated that referral time,age categories,referral radius,different years and seasons were associated with response time.Conclusions With the improvement of technologies and management mechanism,the response time was apparently minimized since the beginning of interhospital transportation.But there is still plenty of room for shortening rsponse time compared with advanced Westem countries.

BACKGROUND:For the department of orthopedics, digital technology can be used for a three-dimensional reconstruction of the fracture site, and visual virtual reset. This not only can preoperatively plan the operation path, make reasonable operation plan, but also can predict the prognosis after surgery. OBJECTIVE:To discuss the feasibility and clinical effect of digital technology for three-dimensional measurement and preoperative design in intertrochanteric fracture patients undergoing proximal femoral nail antirotation. METHODS:Eighty patients of intertrochanteric fractures, who underwent proximal femoral nail antirotation in the Changyi People’s Hospital from January 2010 to January 2014, were selected in this study. According to the order of visiting, they were randomly divided into traditional treatment group and three-dimensional design group, with 40 cases in each group. Patients in the traditional treatment group received proximal femoral nail antirotation. Patients in the three-dimensional design group received preoperative CT scan to establish the digital three-dimensional model of intact femur. The analog was reset by technology. The length and diameter of medul ary cavity were measured. The appropriate specifications of intramedul ary nail were selected. On this basis, the plan of the operation and implementation of operation were made. Operation time, intraoperative bleeding volume and blood transfusion were recorded in the two groups. Hip function was evaluated by hip Harris score. RESULTS AND CONCLUSION:(1) Operations in the two groups were successful. Significant differences in operation time, intraoperative bleeding volume and blood transfusion were determined between the two groups (P<0.05). No significant difference in length of stay was detected between the two groups (P>0.05). (2) Al patients were fol owed up. Postoperative wound was healed. Broken nail or broken rod was not found at the end of the study. (3) At the end of the fol ow-up, the excel ent and good rate of Harris hip score was 95%in the traditional treatment group and 93%in the three-dimensional design group;no significant difference was detected between the two groups. (4) Results suggested that the application of digital department of orthopedics technology for the treatment of intertrochanteric fracture of femur in patients with preoperative three-dimensional measurement and surgical design can significantly shorten the operation time and improve hip function.

Objective To analyze the spatial distribution patterns of rodent community and the risk factors of disease transmission in natural foci of Xiji County,Ningxia,in order to provide a scientific basis for disease control and prevention.Methods Rodents were captured at different habitats in different latitudes which were selected with a stratified sampling method in 2012-2013.Capture rate of different rodent species and spatial distribution patterns of the animal community were analyzed.Antigen and antibody of hantavirus were detected in lung tissue and blood of the rodents with immunofluorescence and enzyme-linked immunosorbent assay (ELISA),respectively.Serum F1 antibody of Yersinia pestis (Y.pestis) was detected with indirect hemagglutination test and Y.pestis from liver and spleen tissue was cultured in vitro.Results Fourteen species of rodents were captured,belonging to 2 orders,7 families and 9 genera.Among them,ground squirrels and wood mouse were dominant species,accounted for 49.56％ (112/226) and 34.51％ (78/226) of the community,respectively.Infections of hantavirus and Y.pestis were not found in the rodent's community.Conclusion With the improvement of ecological environment in Xiji County,the spatial distribution patterns of rodent community is changing; the risk of zoonotic plague is reduced,but the risk of hemorrhagic fever with renal syndrome is being.