BACKGROUND:There are numerous studies about mechanical changes of recast cobalt-chromium ceramic al oys. However, little is reported on the mechanical properties of cobalt-chromium ceramic al oys containing once-used al oys after recasts.
OBJECTIVE:To study the effects of different proportion of once-used al oys to recasting cobalt-chromium al oys on their mechanical properties, including tensile strength, yield strength, elongation and hardness.
METHODS:Cobalt-chromium al oys cast samples were prepared and recast for three times (40%once-used al oys were added per time). The tensile strength, 0.2%yield strength, percentage of elongation, flexural strength and Vickers hardness of each specimen were measured. In addition, microscopic metal ographic observation was done.
RESULTS AND CONCLUSION:Being recast for three times, cobalt-chromiun al oys showed no significant differences on their tensile strength, 0.2%yield strength, percentage of elongation, flexural strength and Vickers hardness. GenerationⅠal oy samples had uniform size, smal diameter and smal carbide size distributing along the grain boundary, mainly exhibiting spherical and irregular wormlike forms. Generations Ⅱ and Ⅲ samples were uniform in shape, but crystal grains were coarsened a little. Carbide from Generation IV samples began to be coarsened, irregular wormlike carbides were increased in amount, and a few of non-metal ic inclusions could be found in grains. Cobalt-chromium al oys can be recast after addition of 40%once-used al oys for three times at least in air environment, without decrease of the mechanical properties.

[Objective]To investigate the characteristics and clinical results of open reduction and internal fixation for fractures of the calcaneus for earthquake patients.[Method]The fractures were classified according to Sanders classification.Fifteen cases(24 fractures) were treated by open reduction and internal fixation.Thirteen cases(21 fractures) were followed up from four,four and half months(average of 4.2 months).[Result]All fractures had been healed.Functional results were evaluated using Marryland Foot Score and excellent results occured in 9(42.9%),good in 10(47.6%),fair in 2(9.5%) and the satisfactory rate was 90.5%.Two cases of incision infection were cured by skin flap transplantation.[Conclusion]Open reduction and internal fixation is an effective method for treatment of displaced intra-articular fractures of the calcaneus.Earthquake patients are not fit for early operation.They should be treated with operation after normal functional index and stable psychological situation.

Objective To observe therapeutic benefits of intravenously transplanted hone marrow mesenchymal stem cells (BMMSCs) on alcohol-associated dementia (AAD) rat model and study its underlying mechanisms.Methods BMMSCs were isolated by the method of differential adhesion and membrane antigens were detected with flowcytometric analysis.To establish AAD model,SD rats were intragastricly administrated with ethanol (20％,8ml/kg) for 28 days.Then BMMSCs were labeled with DAPI and injected into the blood via caudal vein.And animals were evaluated by observing Morris Maze behavior,hippocampal morphology and neuronal apoptosis.The expression of BDNF was detected by the method of immunohistochemistry.And the activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) in rat blood serum were also measured.Results The results of flowcytometry analysis indicated BMMSCs were CD29,CD90-positive,and CD45,CD34-negative.And the cells labeled with DAPI were observed in rat hippocampus 3 days after intravenous injection.Compared with PBS group,the escape latency of rats in BMMSC group was apparently shortened((10.17 ±0.71)s vs.(4.71 ± 0.34)s,P ＜0.01).And the morphological structure was repaired and neuronal apoptosis was reduced in rat hippocampus after BMMSC transplanting((72.67 ± 2.73) vs.(55.5 ± 5.14),P＜0.05).Immunohistochemical results showed that the expression of BDNF was significantly increased in the hippocampus of rats in BMMSC group ((71.54 ± 13.71) vs.(135.25 ± 22.20),P ＜0.05).Also,the activity of GSH-Px was apparently improved in the blood serum of rats treated with BMMSC transplanting ((526.89 ± 62.73) vs.(2592.75 ±243.73),P ＜0.01),but no change for that of T-SOD.Conclusion The results provide a novel therapeutic strategy for improving learning and memory function and reducing hippocampal damage induced by ethanol administration,which is closely related to enhance BDNF expression in the hippocampus and improve the activity of antioxidants.

Objective To reconstitute hair follicles in mice using graft chambers,and to study the effect of different cell types on hair follicle regeneration.Methods Full-thickness skin was obtained from the back of C57BL/6 neonatal mice.Then,epidermal cell suspensions were prepared by shredding epidermis after trypsinization,hair follicles and dermal cells were collected by filtration,low-speed centrifugation and density gradient centrifugation,and hair follicle epithelial cells were obtained via trypsinization of hair follicles followed by filtration.Nude mice were classified into four groups to be transplanted with epidermal cells + follicular buds,dermal cells alone,epidermal cells + follicular buds + dermal cells,follicular epithelial cells + dermal cells,respectively.The cells were implanted into the dorsal skin of nude mice using fold chambers.After the grafting,the growth of skin and hairs was observed at the grafted sites on week 1,2,4 and 8,and skin specimens were obtained on week 2,4,and 8 for histological study of hair follicles using hematoxylin-eosin staining.Results After grafting,the chambers on the back of nude mice began to shed with crust formation on week 1; stunted hairs came out and follicle-like structures were seen under the microscope on week 2 at the grafted sites,normal hairs were observed on week 4 and 8 in all the mice except for those transplanted with epidermal cells + follicular buds,and the growth of hairs in mice grafted with epidermal cells + follicular buds + dermal cells and mice grafted with follicular epithelial cells +dermal cells was superior to that in mice grafted with dermal cells alone.Conclusions Hair follicles can regenerate after hair follicle cell transplantation into dorsal chambers in nude mice.Both epidermal cells and dermal cells play indispensable roles in hair follicle reconstitution.

Objective To study the role of src-suppressed C kinase substrate (SSeCKS) in the secretion of tumor necrosis factor (TNF-α) in rat pulmonary micro-vascular endothelial cells (PMVEC) induced by lipopolysaccharide (LPS).Methods Wistar rat PMVEC cultured in vitro were randomly (random number) divided into several groups (n =4) as per exposure to given dosage of LPS for different lengths of time and to different dosages of LPS for given length of time.After PMVEC exposed to 10 mg/L LPS for 1 hour (h),3 h,6 h,12 h and 24 h or 0.1 mg/L,1 mg/L and 10 mg/L LPS for 24 h,the levels of TNF-αin the supernatant of culture medium were examined by the method of enzyme linked immunosorbent assay (ELISA).Another PMVEC was pre-treated by protein kinase C (PKC) inhibitor bis-indolylmaleimide (BIM) for 0.5 h or had the transfection of SSeCKS-specific small interfering RNA (siRNA) for 48 h before 10 mg/L LPS challenge for 24 h,and subsequently the supernatant was also examined by ELISA.One-way analysis of variance (ANOVA) was employed for statistical analysis by SPSS version 10.0 to compare values among all groups.A significant difference was presumed as a probability value ＜ 0.05.Results After PMVEC incubated with 0.1 mg/L,1 mg/L and 10 mg/L LPS for 24 hours,the levels of TNF-αsecreted were (253.70 ± 23.55),(327.88 ± 37.25),(403.20 ± 36.22),respectively,which were higher than that in un-stimulated PMVEC (82.28 ± 22.56,all P =0.000).After 10 mg/L LPS challenge for one hour,the level of TNF-αin the supernatant of PMVEC raised substantially (170.11 ±49.22),peaked at the time of 6 h (404.82 ± 13.78),then persisted at a higher level until 24 h (395.67 ± 36.23) than that in un-stimulated PMVEC (84.60 ± 23.61,P =0.001,0.000,0.000,respectively).After PMVEC pre-incubated with BIM,the level of LPS-induced TNF-αdecreased obviously (200.44 ± 27.39 vs.402.28 ± 31.07,P =0.000).Compared with LPS challenged PMVEC (407.28 ± 32.64),depletion of endogenous SSeCKS in PMVEC after inhibited by SSeCKS-siRNA significantly attenuated increase in the level of LPS-induced TNF-α (195.20 ± 13.28,P =0.000).Conclusions Down-activation of SSeCKS and PKC can inhibit the secretion of TNF-αin PMVEC induced by LPS,relieving the inflammatory response of PMVEC.

Objective We tried to design a Instructor Rating Scale Identified by Nursing Students,and then evaluate its rehability and validity.Methods The original item pool was formulated by investigating 351 nursing students with convenience samphng method to develop a prehminary scale.Then it was used to investigate 273 nursing students to test its rehability and validity.Results The formal scale consisted of six dimensions,which contained 19 items.The cumative contribution rate of these dimensions was 62.30％.The Cronbach's α coefficient was 0.54,test and re-test reliability was 0.48.Conclusions The Instructor Rating Scale Identified by Nursing Students can be applied to evaluate the instructors by nursing students.

Objective To compare the changes in TLR4-NF-κB signaling pathway in infant and adult mice infected with influenza virus, and to provide experimental evidence for the study of immunopathological mechanism in pediatric respiratory virus susceptibility. Methods Immunohistochemistry and RT-PCR were applied to detect the expressions of lung TLR4 and NF-κB P65 mRNA and proteins in the infant and adult mice, and to compare the changes in TLR4-NF-κB P65 signaling pathway after infection with influenza virus.Results (1) The infant model group showed the strongest expression of TLR4 protein in the lung tissue, compared with that in the normal group and adult model group showing significant differences (P<0.05).(2) The expression of NF-κB P65 protein in the lung tissue was strongest in the infant model group, and it was gradually increased over time, showing a significant difference between each time point and the next time point (P<0.05).(3) The infant model group showed the strongest expression of TLR4 mRNA in lung tissue, significantly higher than that in the normal and adult model groups (P<0.05).(4) The expression of NF-κB P65 mRNA in the lung tissue was highest in the infant model group, and significantly higher than that in the normal and the adult model groups ( P<0.05) , and it was gradually increased with the time.Conclusions The over-activation of TLR4-NF-κB P65 signaling pathway may be one of the immunopathological mechanisms of serious injury in the lung tissue in infant rats.

Objective:To compare the clinical effects and improvement of serum hormone levels of kidney tonifying and blood circulation recipe and mirena in the treatment of perimenopasual dysfunctional uterine bleeding.Methods:92 cases of perimenopausal patients with dysfunctional uterine bleeding in our hospital from July 2013 to November 2016 were selected and divided into group A and group B with 46 cases in each group.Group A was orally administered with kidney tonifying and blood circulation recipe,and group B was administered with mirena.Both groups were treated for 3 periods.The efficacy and incidences of adverse effect in two groups were observed.The levels of serum hormones and hemoglobin (Hb),and endometial thickness (ET) were detected in two groups.The indices of serum hormone included follicle-stimulating hormone (FSH),luteinizing hormone (LH),progestone (P) and estradiol (E2).Results:No significant difference was found in the total effective rate between two groups (P＞0.05).After treatment,the levels of serum FSH,LH,E2 and P as well as ET and Hb in both groups were all significantly lower than those before treatment (P＜0.01),and the levels of serum FSH,LH,E2 and P as well as ET of group B were significantly lower than those of group A (P＜0.01),no significant difference in the Hb level between two groups (P＞0.05).The incidence of adverse reactions of group B (15.22％) was significantly higher than that of group A(0％) (P＜0.01).Conclusions:The kidney tonifying and blood circulation recipe had similar effect as mirena in the treatment of perimenopasual dysfunctional uterine bleeding,while mirena had strong improving effect in serum hormone level and ET,kidney tonifying and blood circulation recipe had higher security.

Purpose To investigate the diagnostic value of dual energy CT spectrum curve combined with CT morphology in central lymph node metastasis of papillary thyroid carcinoma (PTC).Materials and Methods Thirty-one PTC patients who accepted dual energy CT double-phase enhanced scan before surgery were analyzed.Central lymph nodes with short diameter ＞ 5 mm were labelled using axial plus 3D positioning.Preoperative labelled lymph nodes were collected and marked during operation.The CT morphology of metastatic lymph nodes was analyzed.The spectrum curve slope (K) difference between metastatic and non-metastatic lymph nodes of arterial-phase and venous-phase primary lesion was compared.The critical K value and the diagnostic efficacy of K value combined with morphology were obtained according to receiver operating characteristic (ROC) curve.Results A total of 73 central lymph nodes were obtained from 31 patients,among which 51 were metastatic and 22 were non-metastatic.There was no significant difference in K value between metastatic and non-metastatic lymph nodes of arterial phase group (P＞0.05).While,there was a significant difference in K value between metastatic and non-metastatic lymph nodes of venous phase group (P＜0.05).For venous phase,the sensitivity and specificity of the K value in diagnosing central lymph node metastasis were 62.7％ and 59.1％,respectively,and combined with morphology,the sensitivity and specificity reached 76.5％ and 81.8％,respectively.Conclusion The K value of CT spectrum curve is of certain significance in predicting PTC central lymph node metastasis,and the K value combined with CT morphology can improve the accuracy of diagnosis.

BACKGROUND:Chitin has been found to be a good biomaterial, but research on chitin carrying corneal epithelial cel s for rabbit corneal epithelial injury is little reported. OBJECTIVE:To investigate the repair outcomes of chitin hybrid membrane carrying corneal epithelial cel s in the rabbit corneal epithelial injury.METHODS:Eighteen New Zealand white rabbits were enrol ed and made into left corneal epithelial injury models, and then randomized into two groups and treated with chitin hybrid membrane carrying corneal epithelial cel s (experimental group) and chitin hybrid membrane (control group), respectively. The damage area, histological changes and ultrastructure of the cornea were observed at 1, 3, and 7 days after implantation. RESULTS AND CONCLUSION:Damage area of the cornea in the experimental group was significantly less than that in the control group at 1 and 3 days after implantation (P<0.05), and the cornea in both two groups healed wel at 7 days after implantation. At 7 days after implantation, in both two groups, the corneal epithelium with six layers adhered to the corneal stroma closely, which was repaired completely and regularly. Comparatively speaking, the cornea in the experimental group possessed smooth outer layer. Besides, in the experimental group, the hexagonal corneal epithelial cel s arranged closely with flat surface;while the hexagonal corneal epithelial cel s in the control group showed no smooth surface and gaps between cel s. These results indicate that chitin hybrid membrane carrying corneal epithelial cel s promotes the repair of rabbit corneal epithelial injury.