[Advance in immunotherapy on biliary tract cancers]

Biliary tract cancers(BTC),including gallbladder cancer and cholangiocarcinoma,has the characteristics of low early diagnosis rate,complex anatomy,insensitivity to radiotherapy and chemotherapy, and poor prognosis.In recent years,immunotherapy as a new method,has made great progress in the treatment of advanced malignant tumors.Immunotherapy is gradually applied in the treatment of BTC,such as inhibitory agents targeting the immune checkpoint receptor pathway,adoptive immunotherapy and tumor vaccines.

Zika virus NS2A protein induces the degradation of KPNA2 (karyopherin subunit alpha 2) via chaperone-mediated autophagy

KPNA2/importin-alpha1 (karyopherin subunit alpha 2) is the primary nucleocytoplasmic transporter for some transcription factors to activate cellular proliferation and differentiation. Aberrant increase of KPNA2 level is identified as a prognostic marker in a variety of cancers. Yet, the turnover mechanism of KPNA2 remains unknown. Here, we demonstrate that KPNA2 is degraded via the chaperone-mediated autophagy (CMA) and that Zika virus (ZIKV) enhances the KPNA2 degradation. KPNA2 contains a CMA motif, which possesses an indispensable residue Gln109 for the CMA-mediated degradation. RNAi-mediated knockdown of LAMP2A, a vital component of the CMA pathway, led to a higher level of KPNA2. Moreover, ZIKV reduced KPNA2 via the viral NS2A protein, which contains an essential residue Thr100 for inducing the CMA-mediated KPNA2 degradation. Notably, mutant ZIKV with T100A alteration in NS2A replicates much weaker than the wild-type virus. Also, knockdown of KPNA2 led to a higher ZIKV viral yield, which indicates that KPNA2 mediates certain antiviral effects. These data provide insights into the KPNA2 turnover and the ZIKV-cell interactions.

[Influence of the stiffness of three-dimensionally bioprinted extracellular matrix analogue on the differentiation of bone mesenchymal stem cells into skin appendage cells]

Objective: To observe the influence of the stiffness of three-dimensionally bioprinted extracellular matrix analogue on the differentiation of bone marrow mesenchymal stem cells (BMSCs) into skin appendage cells. Methods: (1) Sodium alginate of 1 g and 4 g gelatin, 3 g sodium alginate and 8 g gelatin were mixed respectively, and the two mixtures were dissolved in 100 mL ultra-pure water respectively to prepare two sodium alginate-gelatin composite hydrogels, named 1A4G hydrogel and 3A8G hydrogel, which were used in the subsequent experiments. The morphology of the two hydrogels at room temperature, after condensation for 15-30 min at 4 ℃ (the same condensation condition below), after condensation and cross-linking with 25 g/L calcium chloride solution (the same cross-linking condition below), and after condensation and three-dimensional printing with a three-dimensional bioprinter (the same three-dimensional printer below) and cross-linking were observed respectively. Young's modulus (stiffness) of the two kinds of hydrogels was measured by Young's modulus tester after condensation and cross-linking (n=3). Two kinds of hydrogels were cross-linked and freeze-dried, and their pore structure was observed by scanning electron microscope. Two hydrogels were cross-linked and freeze-dried, and the porosity was detected by anhydrous ethanol replacement method (n=3). (2) BMSCs were isolated from femur and tibia of 20 C57BL/6 mice (no limitation with sex, born 7 days) and cultured, and the second passage of cells was used for further test. The BMSCs single cell suspension (1.0×10(7) /mL) was mixed with 1A4G hydrogel and 3A8G hydrogel respectively at 1∶9 volume ratio to prepare BMSCs-loaded 1A4G hydrogel and BMSCs-loaded 3A8G hydrogel for three-dimensional printing. One construct was printed with 1 mL cell-loaded hydrogel (the same dosage for printing below). Mesenchymal stem cells (MSCs) specific medium was added after cross-linking, and the printed constructs were divided into 1A4G group and 3A8G group according to the hydrogel. One construct of each group cultured for 7 days was tested with live/dead kit to count the live cells and dead cells in 50-fold field of view. Nine printed constructs from each of the two groups were taken, and BMSCs of nine wells (1.0×10(6) per well) cultured with 2 mL MSCs specific medium were set as two-dimensional culture group. After 1, 3, 5 day (s) of culture, three printed constructs from 1A4G group and 3A8G group respectively and three wells of cells from two-dimensional culture group were taken to detect the absorbance value in culture medium by cell counting kit 8, denoting the cell proliferation activity. (3) BMSCs-loaded 1A4G hydrogel and BMSCs-loaded 3A8G hydrogel of 10 mL respectively were prepared as in experiment (2), which were respectively mixed with 0.5 mL plantar dermis homogenate extracted from 10 C57BL/6 mice of 1 day postnatal with unknown sex, then three-dimensionally printed, cross-linked, cultured with MSCs specific medium for 3 days and then changed to sweat gland specific medium. The printed constructs were divided into 1A4G group and 3A8G group according to their hydrogel. After 7 days of culture with sweat gland specific medium, the expressions of epithelial cell surface markers cytokeratin-5 (CK5) and CK14, sweat gland cell surface markers CK18 and Na(+) /K(+) -ATPase (NKA), and hair follicle cell surface markers CK17 and alkaline phosphatase (ALP) at protein level in cells of printed constructs in the two groups were detected by immunofluorescence method. The expressions of CK5, CK14, CK18, NKA (detecting ATP1a1), CK17, and ALP at mRNA level in cells of printed constructs in the two groups were detected with real-time fluorescent quantitative reverse transcription polymerase chain reaction (n=3). Data were statistically analyzed with independent sample t test, Fisher's exact probability test, analysis of variance for factorial design, and Bonferroni method. Results: (1) Compared with that of 3A8G hydrogel, 1A4G hydrogel had lower viscosity and better fluidity at room temperature. Both kinds of hydrogels were gel-like after condensation, based on which, the shape of cross-linked hydrogels was uniform and regular, with three-dimensional printing and cross-linking made hrdrogels forming solid crisscross cylindrical constructs. The Young's modulus of 1A4G hydrogel was (52±6) kPa, which was obviously lower than (218±5) kPa of 3A8G hydrogel (t=40.470, P<0.01). The pore structure of the two hydrogels was similar, with all the cross-sections showing porous network structure. The porosity of the two hydrogels was similar (t=0.930, P>0.05). (2) The distribution of live/dead cells between 1A4G group and 3A8G group was similar after 7 days of culture (P>0.05), most of which were live cells. The absorbance value in culture medium of printed constructs among 1A4G group, 3A8G group, and two-dimensional culture group didn't show statistically significant differences after 1, 3, 5 day (s) of culture (P>0.05). Compared with that after 1 day of culture within each group, the absorbance value in culture medium of printed constructs in 1A4G group and 3A8G group was significantly increased after 3 and 5 days of culture (P<0.05 or P<0.01), and the absorbance value in culture medium of cells in two-dimensional culture group was significantly increased after 5 days of culture (P<0.01). Compared with that after 3 days of culture within each group, the absorbance value in culture medium of printed constructs in 1A4G group and 3A8G group and that of cells in two-dimensional culture group was significantly increased after 5 days of culture (P<0.01). (3) After 7 days of culture with sweat gland specific medium, the CK5, CK14, CK18, NKA, CK17, and ALP were positively expressed at protein level in cells of printed constructs in the two groups. After 7 days of culture with sweat gland specific medium, the expressions of CK5, CK14, CK18, and NKA at mRNA level in cells of printed constructs were close between the two groups (t=0.362, 0.807, 0.223, 1.356, P>0.05); the expressions of CK17 and ALP at mRNA level in cells of printed constructs in 3A8G group were 1.96±0.21 and 55.57±11.49, respectively, which were significantly higher than 1.05±0.42 and 2.01±0.27 in 1A4G group (t=3.333, 8.074, P<0.05 or P<0.01). Conclusions: BMSCs cultured three-dimensionally in 1A4G and 3A8G hydrogels tend to differentiate into sweat gland cells, but the BMSCs cultured three-dimensionally in 3A8G hydrogel show a stronger tendency to differentiate into hair follicle cells than the cells cultured in 1A4G hydrogel. It suggests that relatively high stiffness of three-dimensionally bioprinted extracellular matrix analogue facilitates not only differentiation of BMSCs into sweat gland cells, but also their differentiation into hair follicle cells.

Application Exploration of Participation Rules in Environmental Damage Identification

Abstract

[Research progress on the occurrence and prevention of low back pain in naval officers and soldiers]

Low back pain (LBP) is a common occupational disease among naval officers and soldiers. This article reviewed the incidence of LBP in naval personnel in different positions in recent years, and analyzed the causes combined with the operating environment and occupational characteristics of personnel in different positions in order to clarify the causes of LBP in naval officers and soldiers in different positions and improve their awareness of the disease. Moreover, this study aims to help naval officers and soldiers to take protective measures in training life to reduce the incidence of LBP.

[Effectiveness and safety of sofosbuvir/velpatasvir combination ± ribavirin in the treatment of Chinese adults with chronic hepatitis C virus infection]

Objective: To understand the effectiveness and safety sofosbuvir/velpatasvir (SOF/VEL) combination ±ribavirin in the treatment of chronic hepatitis C virus (HCV) infection in China. Methods: A total of 96 Chinese adults with chronic HCV infection who were treated with SOF/VEL combination ± ribavirin for 12 weeks between July 2018 and February 2020 were selected. HCV RNA, routine blood test, liver, kidney and coagulation function, abdominal Color Doppler ultrasound or CT and liver stiffness were detected at baseline, 4 weeks of treatment, end of treatment and 12 weeks of follow-up. Adverse events and laboratory abnormalities during the treatment were recorded. A t-test was used to compare the measurement data between the two groups, and the analysis of variance was used for multiple group comparison. Results: A total of 93 cases (96.9%) achieved sustained virological response (SVR12), of which 3 cases had relapsed. 88 cases (91.7%, 88/96) had achieved rapid virological response (RVR). 96 cases (100%) had achieved virological response by the end of treatment (EOT). In patients with decompensated liver cirrhosis, the average baseline Child-Pugh score and Model for End-Stage Liver Disease score was 7.4±1.0, and 11.4±1.7, respectively. Among them, 12 cases of the SOF/VEL combined with RBV treatment had achieved SVR12 (100%) at 12 weeks, while only 3 of the 5 cases of single-tablet regimen of SOF/VEL had achieved SVR12 (60%). There was no significant difference between creatinine levels and baseline during or 12 weeks after treatment. The incidence of adverse events in patients with chronic hepatitis C and compensated cirrhosis was 6.3% (5/79), while that in patients with decompensated cirrhosis was 35.3% (6/17). The most common adverse events were hyperbilirubinemia, fatigue and anemia. There were no serious adverse events, deaths or discontinuation of treatment due to adverse events. Conclusion: SOF/VEL combination ± ribavirin in the treatment of various common genotypes of chronic hepatitis C, compensated cirrhosis, decompensated cirrhosis and hepatocellular carcinoma has higher SVR12 in China, and the tolerance and safety are good.

[Evaluation of drug-drug interactions between yimitasvir phosphate capsules with sofosbuvir tablets, omeprazole magnesium enteric-coated tablets, and rosuvastatin calcium tablets]

Objective: To evaluate the drug-drug interactions and the tolerability of combined medication between yimitasvir phosphate capsules with sofosbuvir tablets, omeprazole magnesium enteric-coated tablets, and rosuvastatin calcium tablets in healthy volunteers. Methods: A randomized, open, and continuous administration design was used in trial 1 (yimitasvir phosphate capsules with sofosbuvir tablets). 28 subjects were randomly divided into two groups. A non-randomized, open design was used in trial 2 (yimitasvir phosphate capsules with omeprazole magnesium enteric-coated tablets), and included 42 subjects divided into three groups. The open design method was used in trial 3 (yimitasvir phosphate capsules with rosuvastatin calcium tablets), and included 14 subjects. The plasma concentrations of yimitasvir phosphate, sofosbuvir and their main metabolites GS-331007, omeprazole and rosuvastatin were validated by a liquid chromatography/tandem mass spectrometry (LC-MS/MS). The pharmacokinetic parameters were calculated by Phoenix winNonlin software. Results: (1) in trial 1, after single and co-administration, the 90% CI of sofosbuvir C(max) and AUC(0-tau) geometric mean ratio (GMR) were 152.0% (118.0% ~ 197.0%) and 230.0% (184.0% ~ 287.0%), with an increase of 52.0% and 130.0% compared to single dose of sofosbuvir, respectively. The 90% CI of GS-331007 C(max) GMR was 74.0% (67.5% ~ 81.2%) and reduced by 26% compared to single dose of sofosbuvir. (2) in trial 2, the 90% CI of C(max) GMR after yimitasvir single or co-administration at the same time, with a 4-hours interval, or with a 12- hours interval were 68.9% (44.5% ~ 106.7%) , 64.0% (43.8% ~ 93.6%) and 56.4%(38.9% ~ 81.9%), and the 90% CI of AUC(0-t) GMR were 68.6% (46.5% ~ 101.2%), 68.3% (47.6% ~ 98.0%) and 60.5% (41.8% ~ 87.5%), respectively. Compared with single dose of yimitasvir, the C(max) and AUC(0-t) were decreased by 31.1% and 31.4%, 36.0% and 31.7%, 43.6% and 39.5%, respectively. (3) In trial 3, after single and co-administration, the 90% CI of rosuvastatin C(max) and AUC(0-72) GMR were 172.4% (153.6% ~ 193.5%) and 158.0% (144.3% ~ 172.9%), respectively, with an increase of 74.9% and 60.5% compared to single dose of rosuvastatin. There were no serious adverse events and adverse events leading to withdrawal from the trial. Conclusion: Yimitasvir phosphate capsules have drug-drug interactions with sofosbuvir tablets, omeprazole magnesium enteric-coated tablets, and rosuvastatin calcium tablets.

[Clinical value of extended radical resection for pT3 stage gallbladder cancer]

Objective: To investigate the clinical value of extended radical resection for stage pT3 gallbladder cancer (GBC). Methods: The clinical and pathological data of 323 patients with stage pT3 GBC who received regional radical resection or extended radical resection in 7 domestic hepatobiliary centers in China from January 2013 to December 2018 were retrospectively analyzed. The propensity score matching method was used to select 36 cases in each of the regional radical resection group (group A1) and the extended radical resection group (group B1). The surgical indicators and overall survival rates of the two groups were compared, and prognostic factors were analyzed. Results: The number of positive lymph nodes [2(0,3)] and the total number of lymph nodes removed [3(1,4)] in group B1 were both higher than those in group A1 [1(0,1), 4(2,7)] (all P<0.05). There was no significant difference in other clinical and pathological factors between the two groups (all P>0.05). The 1, 3, and 5-year survival rates of group A1 were 75%, 44%, and 29%, respectively, which were significantly higher than those of group B1 of 50%, 15%, and 11% (χ(2)=11.311, all P<0.001). Extensive radical resection (HR=2.161, 95%CI: 1.222-3.821), hepatic parenchymal invasion (HR=2.324, 95%CI: 1.305-4.139), positive lymph node rate ≥1/3 (HR=2.927, 95%CI: 1.641-5.220), and ⅢB/ⅣB staging (HR=3.325, 95%CI: 1.750-6.320) are risk factors for the prognosis of GBC patients (all P<0.05), of which extended radical resection (HR=1.969, 95%CI: 1.083-3.581) was an independent risk factor for prognosis (P<0.05). When the ratio of positive lymph nodes was<1/3 and the tumor invaded the hepatic parenchyma, the overall survival rate of group B1 was significantly lower than that of group A1 (all P<0.05). Conclusions: The overall survival rate in patients with stage pT3 GBC whose lymph node positive rate<1/3 and/or hepatic parenchymal invaded cannot be improved by extended radical resection. Extended radical resection is an independent risk factor for patient prognosis.

[Preparation and preliminary research on the characteristics of modified nano-bioglass hydrogel]

Objective: To explore the preparation and preliminary research on the characteristics of modified nano-bioglass hydrogel. Methods: (1) The nano-bioglass suspension was prepared by adding 67 mL nano-silica suspension into 400 mL saturated calcium hydroxide solution, and its suspension stability was observed. (2) The hydrogel with final mass fraction of 10% gelatin and 1% sodium alginate was prepared and set as control group. On the basis of the hydrogel in control group, the nano-bioglass suspension prepared in experiment (1) was added to prepare the hydrogel with the final mass fraction of 0.5% bioglass, 10% gelatin, and 1% sodium alginate, and the hydrogel was set as the experimental group. The gelling time at 4 and 25 ℃and the dissolution time at 37 ℃ of hydrogel in 2 groups were recorded, and the gelation at 4 and 25 ℃and dissolution condition at 37 ℃of the hydrogel in 2 groups were observed. The hydrogel in 2 groups were collected and cross-linked with 25 g/L calcium chloride solution after cold bath at 4 ℃, and the compression modulus was measured by Young's modulus tester. In addition, the hydrogel in 2 groups were collected and cross-linked as before, and freeze-drying hydrogel was made at -20 ℃. The relative volumes were measured and the porosity of hydrogel in 2 groups was calculated. The number of sample in the experiment was 3. (3) Fibroblasts (Fbs) were isolated and cultured from 12 C57BL/6J mice of 24 hours old and the morphology was observed by inverted microscope, and the third passage of Fbs were cultured for the following experiment. Fbs were collected to make single cell suspension with the cell concentration of 1×10(5)/mL. The single cell suspension was divided into experimental group and control group according the random number table (the same grouping method below), which were added with hydrogel in experimental group and control group prepared in experiment (2), respectively. At culture hour 12, 24, and 48, cells of 3 wells in each group were collected to detect the survival rate by cell counting kit 8 method. (4) The third passage Fbs were collected to prepare the single cell suspension with the cell concentration of (3.0~4.5)×10(7)/mL, which was divided into experimental group and control group, with 1 tube in each group. The single cell suspension in 2 groups were added with green fluorescent probe DIO for staining and then added with 9 mL hydrogel in experimental group and control group prepared in experiment (2), respectively. The mixed solution of Fbs and hydrogel in 2 groups was cross-linked as before to make cell-loaded hydrogel. On culture day 3, the survival of cells in the hydrogel was observed by laser confocal microscope. The cell-loaded hydrogel was prepared as before and without added with green fluorescent probe DIO. On culture day 7, the adhesion and extension of cells in the hydrogel were observed by scanning electron microscope. (5) Twelve 6-week-old female BALB/c-nu nude mice were collected and divided into experimental group and control group, with 6 mice in each group. A round full-thickness skin defect wound with diameter of 1 cm was made on the back of each mouse. Immediately after injury, one cell-loaded hydrogel block in the experimental group and the control group prepared in experiment (4) was placed in the wound of each mouse in the experimental group and the control group, respectively. On post injury day (PID) 7 and 14, 3 nude mice in each group were sacrificed to collect the wound and wound margin tissue, which was stained with hematoxylin-eosin to observe the wound healing. Data were statistically analyzed with independent sample t test. Results: (1) The nano-bioglass particles could be uniformly dispersed in water and had good suspension stability. (2) The hydrogels of the 2 groups were molten at 37 ℃, and no precipitation of particle was observed. The dissolving time of the hydrogel in the experimental group and the control group at 37 ℃ was 5 and 10 min, respectively. The gelation time of the hydrogel in the experimental group and the control group at 25 ℃ was 30 and 180 min, respectively, and the gelation time of the 2 groups at 4 ℃ was 5 and 10 min, respectively. The compression modulus of hydrogel in the experimental group was (53±6) kPa, which was significantly higher than (23±6) kPa in the control group (t=6.364, P<0.01). The porosity of the hydrogel in the experimental group was (86.1±2.1)%, which was similar to (88.2±4.4)% in the control group (t=1.210, P>0.05). (3) The cells were in long fusiform, and the proportion of nuclei was high, which was accorded with the morphological characteristics of Fbs. At culture hour 12, 24, and 48, the survival rate of cells in the experimental group was (84±4)%, (89±4)%, and (130±10)%, which was similar to (89±5)%, (90±4)%, and (130±11)% in the control group, respectively (t=1. 534, 0.611, 0.148, P>0.05). (4) On culture day 3, the cells in the two groups had complete morphology in the hydrogel, no nuclear lysis or disappearance were observed, the cytoplasm remained intact, and the fluorescence intensity of the cells in the experimental group was significantly stronger than that in the control group. On culture day 7, the cells in the experimental group and the control group adhered and stretched in the hydrogel, and the number of cells in the experimental group adhered to the hydrogel was significantly more than that in the control group. On PID 7, the wound area of the nude mice in the control group and the experimental group were reduced, the reduction area of mice in the experimental group was more obvious, and a large amount of inflammatory cells were seen in and around the wound in the 2 groups. On PID 14, the wound area of the nude mice in the control group was larger than that of the experimental group, and the number of inflammatory cells in and around the wound was significantly more than that in the experimental group. Conclusions: Nano-bioglass hydrogel possesses good physical, chemical, and biological properties, cell loading potential, and the ability to promote wound healing, which means it has a good potential in clinical application.

[Establishment and clinical testing of pancreatic cancer Faster R-CNN AI system based on fast regional convolutional neural network]

Objective: To investigate the effectiveness of an enhanced CT automatic recognition system based on Faster R-CNN for pancreatic cancer and its clinical value. Methods: In this study, 4 024 enhanced CT imaging sequences of 315 patients with pancreatic cancer from January 2013 to May 2016 at the Affiliated Hospital of Qingdao University were collected retrospectively, and 2 614 imaging sequences were input into the faster R-CNN system as training dataset to create an automatic image recognition model, which was then validated by reading 1 410 enhanced CT images of 135 cases of pancreatic cancer.In order to identify its effectiveness, 3 750 CT images of 150 patients with pancreatic lesions were read and a followed-up was carried out.The accuracy and recall rate in detecting nodules were recorded and regression curves were generated.In addition, the accuracy, sensitivity and specificity of Faster R-CNN diagnosis were analyzed, the ROC curves were generated and the area under the curves were calculated. Results: Based on the enhanced CT images of 135 cases, the area under the ROC curve was 0.927 calculated by Faster R-CNN. The accuracy, specificity and sensitivity were 0.902, 0.913 and 0.801 respectively.After the data of 150 patients with pancreatic cancer were verified, 893 CT images showed positive and 2 857 negative.Ninety-eight patients with pancreatic cancer were diagnosed by Faster R-CNN.After the follow-up, it was found that 53 cases were post-operatively proved to be pancreatic ductal carcinoma, 21 cases of pancreatic cystadenocarcinoma, 12 cases of pancreatic cystadenoma, 5 cases of pancreatic cyst, and 7 cases were untreated.During 5 to 17 months after operation, 6 patients died of abdominal tumor infiltration, liver and lung metastasis.Of the 52 patients who were diagnosed negative by Faster R-CNN, 9 were post-operatively proved to be pancreatic ductal carcinoma. Conclusion: Faster R-CNN system has clinical value in helping imaging physicians to diagnose pancreatic cancer.

[Research Yi Jia on the literature of "Fangji Zhuan" in Songshi]

"Fangji Zhuan"(, Biographies of Technicians), a chapter from Songshi(, History of the Song) uses time as a sequence and adopts a narrative method. It contains 42 talents, including ephemeris, five elements of law, medical practitioners, and Taoists. Among them, there are 25 good medical practitioners, which are rich in content and detailed in history. Based on the biographies of medical doctors in "Fangji Zhuan", this article summarizes and records the life history of 25 different types of medical doctors in terms of divisions, contributions, rewards and punishments, etc., which reflects the career status of medical doctors in the Song Dynasty to a certain extent. The role and contribution in medical development are of great significance.

[Feasibility of the determination of plasma vardenafil level in rat by performance liquid chromatography-tandem mass spectrometry]

Objective: To develope and validate a reliable and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination of vardenafil concentration in plasma of rat. Methods: Plasma samples of normal Sprague-Dawley rats were collected. A Phenomenex Synergi Polar-RP 80A column (2.0 mm×50 mm, 4 µm) was used. Column temperature was set at 30 ℃. Mobile phase A was 0.1% formic acid in water; mobile phase B was 0.1% formic acid in acetonitrile. The flow rate was 0.4 ml/minutes. Quantitative determination was performed by electrospray ionization, operating in positive ion multiple reaction monitoring (MRM) mode. Cisapride was used as the internal standard. The feasibility of the method was evaluated by examining its specificity, linearity and quantitative range, precision and accuracy, matrix effects, and stability. Results: Under the selected chromatographic and mass spectrometry conditions, the monitoring ions of vardenafil and internal standard were mass-to-charge ratio（m/z) 489.3/151.2 and 466.4/234.2, the retention times of vardenafil and internal standard were 2.62 and 2.80 minutes, respectively, and the peak shape was satisfactory. The method has good linearity in the concentration range of 0.2-200 ng/ml. The intra-batch precision (%CV) and accuracy (%DEV) of vardenafil were 1.5%-9.7% and -6.8%-6.6%, respectively. The inter-batch precision and accuracy of vardenafil were 3.1% -8.4% and -3.7%-4.6%, respectively. In this sample processing method, the extraction recovery rate of vardenafil was obtained at range of 88.2%-104.6%, which met the requirements for the investigation of extraction recovery rate. In this sample processing method, the normalized matrix factor of each quality control concentration of vardenafil was 1.04, 0.85, and 1.04, and the coefficient of variation (%CV) was in the range of 1.7%-10.7%, which met the requirements for the investigation of matrix effects. Variations of short-term stability, long-term stability, and stability of 4 freeze-thaw cycles of vardenafil was within ±15%, and the coefficient of variation were within 5%. Conclusion: The high performance liquid chromatography-tandem mass spectrometry method established in this study is feasible for the measurement of concentration of vardenafil in rat plasma and this method has good specificity and high accuracy, and can be used to detect the concentration of vardenafil in rat plasma.

[Etiology and molecular-epidemiological characteristics of viral meningo-encephalitis in Zhejiang province, 2002-2018]

Objective: To understand the pathogens and molecular-epidemiologic characteristics of viral meningo-encephalitis in Zhejiang province during 2002 to 2018. Methods: All the samples were collected from suspected patients admitted to the hospitals under the monitoring program. Of the total samples, 2 173 were cerebrospinal fluids while the other 455 were stool specimens. Cerebrospinal fluid (CSF) samples were subject to real-time qPCR for the detection of Human enterovirus (HEV), Mumps virus (MuV), Herpes simplex virus (HSV), Cytomegalovirus (CMV) and Japanese encephalitis virus (JEV). Stool sample were subject to real-time qPCR for HEV. ELISA was used to detect the IgM antibodies in CSF, in the 5 kinds of virus mentioned above. VP1 genes from all RNA-positive specimen were amplified, sequenced, for typing and for evolution analysis. Results: 871 (40.1%) of the 2 173 samples were detected as HEV nucleic acid positive during 2002 to 2018. 654 (38.1%) of the 1 718 CSF sample were HEV nucleic acid positive while 217 (47.7%) of the 455 stool sample were HEV nucleic acid positive. Among the total positive nucleic acid sample, 670 of them were VP1 sequence positive, including 5 HEV-A and 665 HEV-B. There were 23 HEV serotypes, including Coxsackievirus (CV) CVA4, CVA6, CVA9, CVA10, CVB1-5, Echovirus (EchoV; E) E3, E4, E6,E7, E9, E11, E14, E16, E18, E21, E25, E30, E33 and EV-71. The top three serotypes went to E30, E6 and CVB5. These three serotypes presented enhanced viral activity in every several years. 795 CSF samples were detected as virus nucleic acid positive, including 374 HEV, 6 MuV, 5 HSV and 5 CMV, from 2012 to 2015 and in 2018. 5 kinds of IgM antibodies were detected simultaneously in 368 CSF samples, including 2 HEV positive, 6 JEV positive and 1 MuV positive for 5 viruses, respectively. Except for EV-71, there were 517 EchoV and 152 CV viruses presented, with the ratio of 3.4∶1. These two kinds of viruses alternately changed for each predominant epidemic strains in every 3-5 years. Based on VP1, results from the phylogenetic tree showed that HEV from Zhejiang province clustered into HEV-A and HEV-B clades respectively. E30 developed both h and i sub-genotypes. Conclusions: HEV-B seemed the main pathogen for viral meningo-encephalitis in Zhejiang province. Ratio of positive detection on EchoV was significantly higher than that on CV. These two kinds of virus alternately presented changing tendency in every several years. Predominant epidemic strains E30, CVB5 and E6 were presenting enhanced viral activity, also in every several years. High correlation was found in both HEV viral activity from the surveillance sites and in time line of the viral meningo-encephalitis outbreaks.

[Controversy and focus on the clinical cognition of hilar cholangiocarcinoma]

For patients with hilar cholangiocarcinoma, surgical resection is their only chance of cure. However, the overall prognosis remains dismal. Inrecent years, the clinical cognition, diagnosis and treatment strategies of hilar cholangiocarcinoma have made great progress. Still, a series of controversies remain unresolved and there's an apparent lack of high-level evidence in the current guidelines. These problems are not only related to the reasonable choice of operation and the prognosis of patients, but also account for the source of clinical heterogeneity in multicenter clinical trials. This article reviews and discusses some debatable issues with the aim toinspire future studies.

[Analysis of the relationship between the number of lymph nodes examined and prognosis for curatively resected gallbladder carcinoma: a multi-institutional study]

Objective: To examine the role of the number of lymph nodes examined(NLNE) on the prognosis of patients with curatively resected gallbladder carcinoma(GBC). Methods: The clinicopathological data and prognosis of 401 patients with GBC who underwent radical surgery from six institutions of China from January 2013 to December 2017 were analyzed retrospectively. There were 153 males(38.2%) and 248 females(61.8%), with age of (62.0±10.5) years (range: 30-88 years). Fifty-three patients(22.2%) were accompanied by jaundice. All patients underwent radical resection+regional lymphadenectomy.R0 or R1 resection was confirmed by postoperative pathological examination.The different cut-off values of NLNE were determined by the X-tile software, the optimal cut-off values were identified by analyzing the relationship between different cut-off values of NLNE with survival rate. Kaplan-Meier method was used for survival analysis. Univariate and multivariate analysis were implemented respectively using the Log-rank test and Cox proportional hazard model. Results: Among the 401 patients enrolled, 135 cases (33.6%) had lymphatic metastasis, of which 98 cases were in N1 stage(24.4%) and 37 cases were in N2 stage(9.2%).A total of 2 794 NLNE were retrieved, with a median count of 6 (5).The median positive lymph nodes count was 0 (1), and the median positive lymph nodes ratio was 0 (IQR, 0-0.2). Since the 12 and 15 were determined as the cut-off values by X-tile, all patients were divided into three groups of 1-11, 12-15 and ≥16.The 3-year survival rate of the three groups was 45.2%, 74.5%, 12.0% respectively, with statistically significant difference between three groups (χ(2)=10.94, P<0.01). The results of multivariate analysis showed that NLNE was an independent prognostic factor for overall survival (P<0.05). Further analysis was performed specifically for subgroup of T stages. For T1b patients, the prognosis of the NLNE with 1-7 group was significantly better than that of the ≥8 group(χ(2)=4.610, P<0.05). For T2 patients, the prognosis of the TLNE ≥7 group was significantly better than that of 1 -6 group (χ(2)=4.287, P<0.05). For T3 and T4 patients, the prognosis of the TLNE with 12 - 15 group was significantly better than that of 1 -11 group (χ(2)=5.007, P<0.01) and ≥16 group (χ(2)=10.158, P<0.01). Conclusions: The NLNE is an independent factor affecting the prognosis of patients with GBC.For patients with stage T1b,8 lymph nodes should be retrieved; for patients with stage T2,extensive dissection of more than 6 lymph nodes can significantly improve the prognosis.For advanced patients (stages T3 and T4), extensive dissection with 12-15 lymph nodes is recommended. However, it fails to get more survival benefits by dissecting more than 16 lymph nodes.

[Treatment of postprandial discomfort syndrome in the elderly: a multi-centered prospective randomized controlled clinical study]

Objective: To evaluate the efficacy and safety of Oryz-Aspergillus enzyme and pancreatin tablets (Combizym(®)) in the treatment of postprandial distress syndrome (PDS) in the elderly, compared with gastrointestinal motility drugs. Methods: A prospective randomized controlled trial was designed and registered in the China Clinical Trials Registry (ChiCTR-IPR-16008185). The elderly patients with PDS were randomly divided into three groups, including Mosapride group with Mosapride citrate tablets 5 mg 3 times per day for 2 weeks; Combizym(®) group with Combizym tablets 244 mg 3 times per day for 2 weeks; combined treatment group with both drugs and same doses for 2 weeks. The modified Nepean dyspepsia index (NDSI) score, discomfort intensity score and PDS score were calculated on patients before treatment, at the end of first and second week of treatment, as well as 4 weeks after treatment finished, respectively. Adverse effects were evaluated. Results: A total of 323 patients from 16 tertiary hospitals in China were enrolled in this study. Among them, 105 patients were in Mosapride group, 109 in Combizym(®) group and 109 in combined treatment group. There were 148 males (45.8%) and 175 females (54.2%) with median age 71.4±9.0 years (60-100 years). Baseline characteristics of three groups were comparable. After treatment, the NDSI scores in three groups all decreased significantly (P<0.001), while they were similar between groups (P>0.05). The discomfort intensity score and PDS score in three groups showed a significant reduction after treatment (P<0.001), especially in the combined treatment group. Compared with Mosapride group, the scores in Combizym(®) group decreased significantly after one or two weeks [discomfort intensity score: after one week, 4.0(2.5, 8.0) vs. 6.0(3.0, 10.0); after two weeks, 3.0(0.0, 5.0) vs. 4.0(2.0, 6.0); all P<0.05. PDS score: after one week, 6.0(3.0, 9.0) vs. 7.0(3.5, 10.5); after two weeks, 3.0(0.0, 5.0) vs. 4.0(2.0, 7.0); all P<0.05]. The efficacy rate in all patients after first week of treatment was over 15.0%. The efficacy rates after two weeks were 55.2%, 68.8% and 73.4% in Mosapride group, Combizym(®) group and combined treatment group, respectively. After two week treatment, the efficacy rates in Combizym(®) group (P=0.041) and combined group (P=0.006) were higher than that of Mosapride group. The recurrence rate of Mosapride group was 9.5%, which was significantly higher than that of Combizym(®) group (1.8%, P<0.05) and combined treatment group (1.8%, P<0.05). There were no serious adverse effects in the three groups. Conclusions: The efficacy of Oryz-Aspergillus enzyme and pancreatin tablets is comparable with that of Mosapride in elderly PDS patients, with fewer adverse effects and low recurrence rate. Combination regimen indicates better efficacy than that of Oryz-Aspergillus enzyme and pancreatin tablets or Mosapride alone.

[Recommendations for public health protection against flood disaster]

Flood disaster is one of the most serious natural disasters in the world, and it could pose an inestimable impact on the affected people. Based on existing laws, regulations, and emergency manuals in China, extensive literature review, epidemiological and related protection evidence, and expert consultation, this study analyzed different health risk factors of flood disaster and proposed a multi-stage, multi-population, and multi-phase comprehensive protection measures for the public in the perspective of pre-event prevention, in-event intervention and post-event rescue strategy, which could provide a scientific basis for improving the level of public health protection against the flood disaster and corresponding health outcomes.

Prediction of staggered stacking 2D BeP semiconductor with unique anisotropic electronic properties

By comprehensive structure design and first-principles calculations, we report a novel two-dimensional (2D) BeP nanomaterial with exotic structural and properties. This BeP 2D material is formed by a couple honeycomb sheets by slab staggered stacking and strong interlayer bondings. It behaves as a natural 2D semiconductor with several notable properties: a modest bandgap (~1.34 eV), high room-temperature electron mobility (~10⁴ cm² V^-1 s^-1) and high visible-light absorption coefficient (~10⁵ cm^-1); Moreover, due to the unique stacking topology, BeP may display distinctive direction-dependent electric transport by the anisotropic polarity of electron and hole mobilities, that is, it exhibits n-type (electron mobility  >  hole mobility) along the armchair direction while acts as p -type (hole mobility  >  electron mobility) in the zigzag direction, thus promising for applications in nanoelectronics. The BeP has good dynamic and thermal stabilities and is also the lowest-energy structure of 2D space indicated by particle swarm search, implying the high feasibility of experimental synthesis.

Hybridization Dynamics in CeCoIn_{5} Revealed by Ultrafast Optical Spectroscopy

We investigate the quasiparticle dynamics in the prototypical heavy fermion CeCoIn_{5} using ultrafast optical pump-probe spectroscopy. Our results indicate that this material system undergoes hybridization fluctuations before the establishment of heavy electron coherence, as the temperature decreases from ∼120  K (T^{†}) to ∼55  K (T^{*}). We reveal that the anomalous coherent phonon softening and damping reduction below T^{*} are directly associated with the emergence of collective hybridization. We also discover a distinct collective mode with an energy of ∼8  meV, which may be experimental evidence of the predicted unconventional density wave. Our findings provide important information for understanding the hybridization dynamics in heavy fermion systems.

[Advances in the research of poststernotomy dehiscence and repair with tissue flap transplantation]

Sternotomy is a routine surgical pathway for heart, lung, and mediastinal surgery. Poststernotomy dehiscence is a common complication of sternotomy, in which infection after poststernotomy dehiscence is one of the most serious postoperative complications in cardiothoracic surgery. Previously, conventional dressing, negative pressure wound therapy, and skin stretching device were used in the treatment of poststernotomy dehiscence, but the outcome of each single method was poor, which caused great pain and burden to the patients and their families. In recent years, tissue flap containing rich blood supply has drawn a lot of attention because of its good wound cover, stable thoracic reconstruction, low infection recurrence rate, and less postoperative complication. In this paper, we reviewed the epidemiological characteristics of poststernotomy dehiscence, and summarized the various classifications for poststernotomy dehiscence and the therapeutic effects of different tissue flap repair. We hope that this review would provide a basis for further construction of the treatment system for poststernotomy dehiscence and the formation of a treatment guideline.

[Effect of the number of previous spontaneous abortions on the first in vitro fertilization cycle]

Objective: To investigate the effect of the number of previous spontaneous abortions on the first in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) cycle. Methods: A retrospective case-control study was conducted to analyze the clinical data of 1 279 patients who received IVF/ICSI treatment for the first time from July 2014 to July 2018 in Tianjin Central Hospital of Gynecology Obstetrics;they were divided into 0 time group (group A, n=924), 1 time group (group B, n=267) and 2 times group (group C, n=88) for comparison, according to the previous frequency of spontaneous abortions. Results: There were no statistically significant differences in age, basal testosterone, estradiol, progesterone, prolactin and embryo quality in group A, B and C (all P>0.05). The biochemical pregnancy rate of group C (9.1%) was higher than those of the other two groups (4.1% and 4.1%; all P>0.05). The clinical pregnancy rate of group A (42.5%) [>group B (40.4%) and >group C (35.2%)] was not statistically significant(P>0.05).Early abortion rate in group A (8.9%) was<group B (15.7%), also <group C (38.7%), there were significant differences (all P<0.05).The live birth rate of group C (21.6%) was significantly lower than that of group A (35.5%; P<0.05), but the difference between group C and group B (30.7%) was not statistically significant (P>0.05). Conclusions: Women with a history of one- or two-time spontaneous abortion have no obvious effect on embryo quality, and have a negative impact of clinical pregnancy rate, early abortion rate, live birth rate in the first IVF/ICSI cycle; especially for patients with a history of two times spontaneous abortion, early abortion rate has a significant increase, live birth rate decreases significantly, suggesting that patients with a history of two times of spontaneous abortion should find the causes of miscarriage according to the process of recurrent spontaneous miscarriage and receive treatment if necessary before subsequent pregnancy.