By using a self-developed IF power and a ASTM contact material experimental system of small-capacity and variable frequency, the value of arcing characteristics and the welding force of the silver-based contact material are acquired under low voltage, resistive load and small current at 400 Hz and 50 Hz. By means of an electricity-ray analytical balance, SEM and EDAX, the weighing values of the contact materials and the changes of AgCdO, AgNi, AgC and AgW contact material surface profile and micro-area constituent are obtained and analyzed. The arc erosion causes of silver-based alloy contact materials at 400 Hz and 50 Hz are also discussed.

AIM:To investigate the effect of cigarette smoking condensate on histone deacetylase 2 (HDAC2) and inflammatory mediators in mouse myoblast C 2C12 cells.METHODS:C2C12 cells were treated with cigarette smoke extract (CSE).HDAC2 siRNA was transfected into the cells using Lipofectamine TM 2000.The levels of interleukin-8 (IL-8) and tumor necrosis factor-α( TNF-α) in the culture supernatants were measured by ELISA , and the expression of HDAC2 at mRNA and protein levels was determined by real-time PCR and Western blotting .RESULTS:The expression of HDAC2 at mRNA and protein levels in CSE group was lower than that in control group (P<0.05).The supernatant levels of IL-8 and TNF-αin CSE group were significantly higher than those in control group ( P<0.05 ) .When the cells were transfected with HDAC2 siRNA followed by CSE stimulation , the expression of HDAC2 at mRNA and protein levels was de-creased , and the supernatant levels of IL-8 and TNF-αwere significantly increased as compared with CSE group and control group (P<0.05).CONCLUSION: Under the oxidative stress condition , C2C12 cells generate high levels of IL-8 and TNF-αby down-regulating the expression of HDAC2.

Objective To explore the application value of contrast-enhanced ultrasound(CEUS) in evaluating the effect of neoadjuvant chemotherapy(NAC) on breast cancer.Methods Image features of 80 breast cancer patients with neoadjuvant chemotherapy were observed and analyzed by CEUS.In the process,the changes of primary foci before and after neoadjuvant chemotherapy and the changes of qualitative and quantitative indexes of blood perfusion were evaluated.The correlation between qualitative change and pathological response was also studied.Results The change of focus size measured by CEUS was higher than that of conventional ultrasound before and after neoadjuvant chemotherapy(P ＜0.05).However,there was no significant difference between the two measurements before NAC(P ＞ 0.05).All the qualitative observation indexes of the ultrasound contrast after NAC revealed obviously benign conversion(P ＜0.05).Among them,the pathological response was closely related to the changes of the enhancement degree,the distribution of the contrast agent,the order of the contrast and the contrast mode.After NAC,the perfusion parameters of the lesions showed slowly crawl and slowly retreat,low enhancement and the diminished total amount of microcirculation perfusion.Conclusions Before and after neoadjuvant chemotherapy,the changes of the lesion size deteted by CEUS were more close to the pathological evaluation than those detected by conventional ultrasound.The benign outcome of qualitative and quantitative indexes of the CEUS was more obvious than the changes of the lesion size,which had practical value for guiding the neoadjuvant chemotherapy for breast cancer,especially the CEUS indexes related to pathological assessment.

Objective To discuss the development and content of Chinese mental health assessment guideline.Methods Following literature review,initial assessment items were outlined by authors.A questionnaire survey concerniug assessment criteria was then conducted among the authorities in tbe field of psychology or psychiatry,A working group meeting was held to make the final decision.Results Ninety-five of 192 questionnaires were finally received,and those who knew much well about mental health accounted for 85.3％.Of 24 commonly used definition and criteria,5 assessment criteria and 15 essential items were agreed to use for mental health evaluation in Chinese populations.Conclusion The development of Chinese mental health assessment guideline is important to modify mental health evaluation and health care services in China.

Objective:To investigate the synergistic effect and mechanism of the combined application of recombinant human bone morphogenetic protein-2(rhBMP-2) and basic fibroblast growth factor (bFGF).Methods:24KM male mice were randomly divided into6 groups with4 mice in each group, namely,GroupA(control group),GroupB(only treated with collagen),GroupC(treated with 2 ng bFGF+collagen),GroupD(treated with4 μg rhBMP-2+collagen),GroupE(treated with4 μg rhBMP-2+2 ng bFGF+collagen) andGroupF(treated with4 μg rhBMP-2+4 ng bFGF+collagen). The composites were implanted into the intermuscular septum of hind legs mice; whereas in control group, intermuscular septum of mice was separated and no implantation was performed. General observation, detection of concentration of calcium content, micro computed tomography (Micro-CT), three-dimensional reconstruction scan, measurement of bone mineral density(BMD), bone volume fraction(BVF) and trabecular thickness(Tb.Th), as well as histological observation withHE staining andALP andCD34 immumohistochemical staining were performed.Results:Ectopic osteogenesis was found inGroupsD,E andF mice.The difference in concentration of calcium contentswas statistically significant betweenGroupsD andE(P<0.05), but insignificant betweenGroupsE andF(P>0.05).Micro-CT and three-dimensional reconstruction revealed continuous newborn bone substance in external surface of ectopic bone formation, and the center of bone formation did not show obvious substantial filling by bone substance.The differences in BMD,BVF andTb.Th were statistically significant betweenGroupsD andE orF(P<0.01 or <0.05). HE staining showed that inGroupsD,E andF, newborn bone substance was mainly located at the edge of ectopic bone formation, and the bone formation inGroupsE andF was better than that in GroupD.ALP andCD34 immumohistochemical staining revealed the positive expression mainly at the edge of ectopic bone formation, and area of positiveexpression inGroupsE andF was larger than that inGroupsD.Conclusions:rhBMP-2 possesses the capacity to induce ectopic osteogenesis independently, but bFGF does not have this ability; the combined application of rhBMP-2 and bFGF can enhance the synergetic effect on inducing ectopic osteogenesis.

Objective There were few studies of prediction on type 2 diabetic patients with acute pulmonary thromboembo?lism.To evaluate the performance of the Padua score, revised Geneva score and Wells PE score in the prediction value of diagnosis of type 2 diabetes mellitus with acute pulmonary thromboembolism( APTE) . Methods 151cases with suspected APTE of type 2 diabe?tes were collected from January 2013 to December 2015 by a retrospective case analysis mode. Among 151 pations,80 cases had diag?nosed with pulmonary thromboembolism.The receiver operating characteristic (ROC) curve was used to evaluate the probability of type 2 diabetic patients with APTE predicted by the Padua, the revised Geneva and the Wells PE score. We calculated the Youden Index for the cut?off point. Results The area under curve( AUC) of the ROC curve in the Padua score, revised Geneva score and Wells PE score for APTE was 0.804±0.035、0.635±0.045 and 0.705±0.043. The area under the ROC curve of the Padua score was the highest and there was a significant difference compared with the revised Geneva( P<0.016 7) . The comparison of Padua score and Wells PE for the predication value was no statistically significant difference ( P>0.016 7) . The comparison of revised Geneva score and Wells PE for the predication value was no statistically significant difference ( P>0.016 7) . The cut?off of Padua score was 3 points and Youden Index was 0.51. The cut?off of Revised Geneva was 3 points and Youden In?dex was 0.24. The cut?off of Wells PE score was 1 points and Youden Index was 0.39. Conclusion Padua score, revised Geneva score and Wells PE score in predicting diabetes patients have some ex?tent clinical value terms, which Padua score has higher predictive value than the Revised Geneva.The predictive value of Padua score and Wells PE score was equivalent.However, the predictive value of Padua score is limited.

Objective:To investigatethe maternal and infant adverse outcomes of group B streptococcus (GBS) colonization during the late pregnancy.Methods:A total of 567 pregnant women who underwent obstetrics and gynecology examination in Yuyao People′s Hospital from December 2018 to June 2019 were selected for the study. Internal vaginal secretions of all the pregnant women were extracted from the lower 1/3 of the vagina for bacterial culture, and GBS culture and screening were performed on pregnant women. According to the results of GBS screening, pregnant women were divided into GBS negative group (8 cases) and GBS positive group (559 cases). The general condition and pregnancy outcomes of pregnant women were compared between the two groups, and the correlation between pregnancy outcomes and streptococcus colonization was analyzed.Results:There were no statistically significant differences in age, gestational weeks, number of births, number of pregnancies, history of abortion, residence area and ethnicity between the two groups ( P>0.05). The incidence of premature rupture of membranes and fetal distress in GBS positive group were higher than those in GBS negative group:5/8 vs. 7.69%(43/559), 3/8 vs. 5.01%(28/559), and the differences were statistically significant ( P<0.05). Spearman single factor correlation analysis showed that GBS colonization in pregnant women were positively correlated with premature rupture of membranes and fetal distress ( r = 0.632, 0.573, P<0.05). Conclusions:GBS colonization in late pregnancy is closely related to pregnancy outcomes, and strengthening GBS screening has great significance to reduce adverse pregnancy outcomes.

Objective To investigate the chemical properties of superficial cardiac neurons. Methods By means of immunohistochemical ABC technique,the study was performed concerning the distribution of calcitonin gene-related peptide(CGRP) and substance P(SP) in the canine main cardiac superficial plexus. Results CGRP-immunoreactive(IR) neurons were found in every plexus,but SP-IR neurons could be observed only in dorsal atria plexus(DAP),inter atria plexus(IAP) and aorta-pulmonary plexus(A-PP).The shape and size of CGRP-IR and SP-IR neurons were similar.The comparative study on atria and ventricles indicated that CGRP-IR and SP-IR neurons in atria were more than those in ventricles.Numerous CGRP-IR,SP-IR nerve fibers could be observed in each fat pats and intermyocardiocytes.These nerve fibers were usually situated near blood vessels,or were attached to vessel wall.Somewhat CGRP-IR and SP-IR nerve fibers were connected with myocardiocytes in some regions.Conclusion The results indicated that actually existed two peptides in canine cardiac superficial plexus.These implied that the regulations of the two kinds of peptidergic neurons to atria and ventricle were different.The two kinds of neurons mentioned above were likely to perform different or similar functions in canine heart.CGRP and SP could possibly modulate the activities of myocardiocytes and vessels of heart directly.

Objective To reduce the screening positive rate (SPR) and improve clinical efficiency of maternal serum screening for Down's syndrome.Methods Nine thousand and thirty-three cases of second trimester maternal serum screening for Down's syndrome were included from Apr.2013 to Apr.2014 in the present study.The screening results,all basic data and equation curves were analyzed retrospectively.Based on the data from the authors' laboratory,the important adjustment parameters were simulated.Combined with postnatal follow-up results,the quality and clinical performance of second trimester serum screening for Down's syndrome were evaluated.Results The SPR of second trimester serum screening for Down's syndrome was 6.69％(604/9033),the detection rate (DR) was 75％(3/4),and FPR was 6.65％(601/9033).The median multiple of median (MOM) of alpha-fetoprotein (AFP) was low and SPR was high,and MOM of free human chorionic gonadotropin β subunit (free hCGβ) were high and SPR was high,while MOM of unconjugated estriol (uE3) were a little bit low,and SPR was slightly high.Considering these three factors,it is believed that the screening positive rate is high.By the simulation adjustments of MOM value equations (AFP and free hCGβ) and weight correction equation,the SPR reduced to 4.11％(371/9033) after recalculating the risk,FPR declined to 4.07％(368/9033),and no more Down's syndrome fetus were missed compared with postnatal follow-up results.Conclusion Based on a localized setting depending on the local laboratory data,we suggest that the MOM value distributions(AFP,free hCGβ and uE3) and maternal weight should be regularly adjusted since it is a useful way to reduce the false-positive rate and improve clinical efficiency of maternal serum screening for Down's syndrome.