This paper aims to establish a method for the determination of sulfur dioxide in sulfur fumigation Chinese herbs. Sample powder and hydrochloric acid solution were isolated by paraffin layer in order to avoid early reactions, with the generation of sulfur dioxide, headspace with airtight needle was used to transfer sulfur dioxide into gas chromatograph, and detected with thermal conductivity detector. The analytical performance was demonstrated by the analysis of 12 herbs, spiked at four concentration levels. In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) within 15%, were obtained. The limit of detection (LOD) was below 10 mg x kg(-1). Standard addition can be used for low recovery samples. The method is simple, less time-consuming, specific and sensitive. Methods comparison revealed that gas chromatography is better than traditional titration in terms of method operability, accuracy and specificity, showing good application value.

The paper is to report the establishment of a method for the determination of multi-residue organochlorine and pyrethroid pesticides in traditional Chinese medicines (TCMs). Fifty-six pesticides were extracted by high-speed homogenization, and then purified through gel permeation chromatography (GPC) and solid phase extraction (SPE) cartridges. The residues were simultaneously identified and quantified by GC-ECD equipped with dual tower, dual column and two micro-ECD detectors. The analytical performance was demonstrated by the analysis of 3 TCMs samples' extracts, spiked at three concentration levels for each pesticide. In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) better than 15%, were obtained. The limit of detection (LOD) for most of the targeted pesticides tested was below 0.01 mg kg(-1). The method had good extraction efficiency, purification effect and good reproducibility, which could be applied to the determination of organochlorine and pyrethroid pesticide residues in the routine analysis of TCMs.

To identify Salvia shandongensis and its relatives at molecular level, the psbA-trnH intergenic region of three species including Salvia shandongensis, Salvia miltiorrhiza and S. miltiorrhiza f. alba were amplified and sequenced. Sequences were assembled with CodonCode Aligner. The K2P genetic distances between Salvia shandongensis and its relatives were calculated and UPGMA tree was performed by MEGA5.0. The results indicated that the lengths of psbA-trnH regions of Salvia shandongensis were about 391 bp, while the lengths of psbA-trnH regions of Salvia miltiorrhiza and S. miltiorrhiza f. alba were about 386 bp. The psbA-trnH sequences showed considerable variations between species and thus were revealed as a promising candidate for barcoding of Salvia shandongensis and its relatives. The intra-specific genetic distances of Salvia shandongensis were 0, while the intra-specific genetic distances of Salvia miltiorrhiza and S. miltiorrhiza f. alba were 0.002 and 0.001 respectively. Additionally, the genetic distance of Salvia shandongensis and Salvia miltiorrhiza ranged from 0.034 to 0.04, and the genetic distance of Salvia shandongensis and S. miltiorrhiza f. alba ranged from 0.005 to 0.008, the intra-specific genetic distances of Salvia shandongensis were much smaller than that of Salvia miltiorrhiza and S. miltiorrhiza f. alba; clustering results showed that there were obvious differences between Salvia shandongensis, Salvia miltiorrhiza and S. miltiorrhiza f. alba, which was consistent with morphological characteristics. This study not only firstly provides the scientific basis for establishing the taxonomy position in molecular level and revealing their genetic relationships of S. shandongensis, S. miltiorrhiza and S. miltiorrhiza f. alba; but also provides DNA molecular identification scientific basis for the development of new medicinal plant resources of Salvia shandongensis. Our results suggest that the psbA-trnH intergenic spacer region can be used as a barcoding to identify Salvia shandongensis, Salvia miltiorrhiza and S. miltiorrhiza f. alba.

Carcinoma, Squamous Cell ; Epithelial Cells ; Humans ; Papilloma

AIM: The multi-residues method was used to determine organophosphorus pesticides in traditional Chinese herbal medicines (TCHMs).METHODS: Fifty three pesticides were extracted by high-speed homogenization,and then cleaned sequentially by C_(18) and Carb/NH2 solid phase extraction (SPE) cartridges.The residues were simultaneously identified and quantified by GC-FPD equipped with dual tower,dual column and two FPD detectors.RESULTS: The analytical performance was demonstrated by the analysis of 6 TCHMs samples extracts,spiked at three concentration levels for each pesticide.In general,the recoveries ranging from 70% to 120%,with relative standard deviations (RSDs) less than 15%,were obtained.The limit of detection (LOD) for most of the targeted pesticides tested was below 0.01 mg/kg.CONCLUSION: The method has good extraction efficiency,purification effect and good reproducibility,which can be applied to the determination of organophosphorus pesticide residues in the routine analysis of TCHMs.

AIM:To study a method for the determination of 13 N-methylcarbamate peticides in traditional Chinese herbal medicines(TCHMs).METHODS:Thirteen pesticides were extracted by acetonitrile,and purified through solid phase extraction(SPE)cartridges,then detected by HPLC with post-column derivatization and Fluorescense Detector excited wavelength was 330 nm,emissive wavelength was 465 nm.RESULTS:The analytical performance was demonstrated by the analysis of 6 TCHMs samples' extracts,spiked at three concentration levels for each pesticide.In general,the recoveries ranging from 74.1 to 108.8%,with relative standard deviations(RSDs)better than 15%,were obtained.The limit of quantification(LOD)of 13 pesticides from 0.000 3 to 0.06 mg/kg.CONCLUSION:The method has good extraction efficiency and purification effect,which could be standard of N-methylcarbamate peticides residues in the routine analysis of TCMs.

Objective:To investigate the current status of satisfaction with training program and loyalty to the university among professional postgraduate students majoring in clinical medicine, as well as the association between satisfaction with training program and loyalty to the university.Methods:The 2017 National Medical Student Satisfaction Survey Database was used. A total of 1 944 professional postgraduate students in the second or third year, as well as those with delayed graduation, from 59 postgraduate training colleges and universities who participated in clinical internship were selected. SPSS 20.0 software was used for analysis; descriptive analysis was used to describe satisfaction with training program and loyalty to the university; factor analysis was adopted to calculate comprehensive satisfaction score to reduce the number of variables; logistic regression analysis was applied to investigate the association of general information and satisfaction with training program with loyalty to the university.Results:The professional postgraduate students majoring in clinical medicine had a degree of 60.44% of loyalty to the university. Satisfaction with training program reflected low satisfaction at each link of the training program. For every 1-point increase in the comprehensive satisfaction scores of the four links of courses, research training, college support, and practice, the loyalty to the university was increased to 2.11, 1.83, 1.77, and 1.75 times as the original, respectively, of the baseline scores.Conclusion:There is still room for further improvement in the satisfaction with training program and the loyalty to the university among professional postgraduate students majoring in clinical medicine, and the satisfaction with training program is closely associated with the loyalty to the university. Colleges and universities need to take measures for courses, practice, research training, and college support, so as to improve satisfaction and thus enhance loyalty to the university.

Objective To compare the prevalence of HIV/STD and related health care seeking behaviors among male STD clinic attendees between Xi'an and Xianyang cities.Methods During June and July 2016,206 male STD clinic attendees were studied in Xi'an city,with another 221 male STD clinic attendees in Xianyang city.Cross-sectional questionnaire survey was used to collect attendees' behavioral information.Blood samples were collected via HIV/HCV/Syphilis testing.Results The prevalence rate of HIV infection was 2.4％ (5/206) in Xi'an and 0.9％ (2/221) in Xianyang,with no statistical significant difference between the two cities.The prevalence rate of syphilis was 4.9％ (10/206) in Xi'an,which was significantly lower than 13.6％ (30/221) in Xianyang.The proportion of respondents,diagnosed with other sexually transmitted diseases,in Xi'an was higher than that of Xianyang.The proportions of commercial heterosexual sex and sex with temporary sexual partners in the past 3 months were 18.0％ (37/206) and 15.5％ (32/206) in Xi'an,lower than 46.6％ (103/221) and 15.8％ (35/221) in Xianyang (x2 =39.70,P ＜0.01;x2 =-0.01,P=0.93).The proportions of condom use with commercial sex workers or temporary sexual partners in the past 3 months among Xi'an were 37.8％ (14/37) and 6.3％ (2/32),lower than 93.1％ (95/102)and 57.1％ (20/35) in Xianyang (x2=49.06,P＜0.01;x2=19.63,P＜0.01).Conclusion Differences were noticed between Xi'an and Xianyang city in terms of STD and HIV prevalences,behaviors related to commercial sex and use of condoms among the male STD clinic attendees that calling for targeted actions in control of high risk behaviors in both HIV/AIDS and STDs transmission.

Objective:To investigate the physicochemical and biological properties of different magnesium modified calcium phosphate bone cements.Methods:The different magnesium modified calcium phosphate bone cements were divided into magnesium citrate, magnesium lactate, magnesium malate, magnesium phosphate and magnesium glycinate groups, each of which was added with different magnesium agents in the proportion of 0%, 1%, 3% and 5% of the total weight of calcium phosphate bone cements. The initial and final setting time, injectability, anti-collapse performance and compressive strength of different magnesium modified calcium phosphate bone cements were tested. Furthermore, the screened bone cement extracts were used to culture with third generation osteoblasts. Bioactivity assays were performed using the Cell Proliferation and Toxicity Assay Kit (CCK-8). Alkaline phosphatase (ALP) staining and Alizarin Red S (ARS) staining were performed on osteoblasts to observe the osteogenic activity of magnesium malate modified calcium phosphate bone cements.Results:The addition of different proportions of different magnesium agents led to the shortening of the initial and final setting time of modified calcium phosphate bone cements. Moreover, the final setting time of 5% magnesium malate modified calcium phosphate bone cements was the shortest (<40 minutes), which was significantly shorter compared with other magnesium agents in the same proportion (all P<0.05). With the addition of different magnesium agents in different proportions, the injectability of bone cements was gradually increased, and the injectability of 5% magnesium malate calcium phosphate bone cements reached the highest for (87.3±1.9)%, which was significantly increased compared with other magnesium agents in the same proportion (all P<0.05). The anti-collapse performance of bone cements was decreased with the addition of different magnesium agents in different proportions. Magnesium citrate, magnesium phosphate and magnesium glycinate modified calcium phosphate bone cements could not resist the flushing of deionized water. In particular, magnesium malate modified calcium phosphate bone cements had the best anti-collapse performance, with the maximum weight loss rate for only (9.8±2.3)% after 30 minutes of deionized water flushing, which was better than the rest of the groups (all P<0.05). The compressive strength of magnesium lactate and magnesium phosphate modified calcium phosphate bone cements showed a decrease compared with original calcium phosphate bone cements, while the compressive strength of magnesium citrate and magnesium malate modified calcium phosphate bone cements was significantly increased compared with original calcium phosphate bone cements, of which 3% magnesium malate modified calcium phosphate bone cements had the greatest compressive strength of (6.2±0.2)MPa, significantly higher than the rest of the groups (all P<0.05). The sieve test yielded magnesium malate modified calcium phosphate bone cement, which had a weight loss of (27.0±0.9)% at 35 days in vitro. The release of magnesium ions was increased with increasing magnesium malate dose in the in vitro environment of magnesium malate modified calcium phosphate bone cements in different ratios. A stable magnesium ion release was achieved within 35 days.Also, the pro-proliferative and osteogenic effects of modified calcium phosphate bone cements on osteoblasts were more obvious with increase of magnesium malate dose. For 5% magnesium malate modified calcium phosphate bone cements, the cell number, ALP staining area ratio and calcium nodule area ratio were significantly increased compared with the groups in the proportion of 0% and 1% magnesium malate (all P<0.05). Conclusions:Among magnesium citrate, magnesium lactate, magnesium malate, magnesium phosphate and magnesium glycinate modified calcium phosphate bone cements, magnesium malate modified calcium phosphate bone cements have relatively suitable setting time, excellent anti-collapse performance and mechanical strength. Meanwhile, 5% magnesium malate modified calcium phosphate bone cements have better biological activity among different ratios of magnesium malate modified calcium phosphate bone cements, suggesting a potential value for clinical application.

Objective:To assess the influence of a virtual simulation-based training system for composite resin filling on the knowledge acquisition, skill development, and overall learning experience of undergraduate stomatology students.Methods:Forty-one undergraduate students of grade 2019 majoring in stomatology were divided into two groups for preclinical training before their internships: the experimental group used a virtual training system for composite resin filling, while the control group watched instructional videos of the procedure. The two groups were compared for their first performance in composite resin filling during the internships and teaching feedback. The t-test and chi-square test were conducted for data analysis using SPSS 20.0. Results:After repeatedly using the virtual training system for composite resin filling, the students in the experimental group were able to master the key operational points of the procedure, all achieving high scores (an average of 91.77 points) with an average time of 10.39 minutes. During the internship phase, the experimental group and control group showed significant differences in the accuracy rates of instrument selection (85.71% vs. 40.00%), adhesive applying (76.19% vs. 45.00%), and layered filling (100.00% vs. 75.00%; all P<0.05). All the students unanimously recognized the value of the virtual simulation system and expressed their willingness to use it for preclinical training before internships. Nineteen students (90.48%) were satisfied with the learning experience with the virtual simulation training system. Conclusions:The virtual simulation training system for composite resin filling can improve students' understanding and proficiency levels of the technique before clinical internships, facilitating a smoother transition to the internship phase.