Photon Counting Detector(PCD)is a device used to detect X-ray photons,which can directly convert the energy of photons into electrical signals to achieve photon counting and measurement.PCD-based energy spectrum computed tomography(PCD-CT)technology can provide additional energy spectral imaging information,and improve imaging quality while reducing radiation dose.Compared with energy integrating detectors(EID),PCD has advantages of high energy conversion efficiency,good imaging quality,exquisite structural design,and wide application range.It has broad application prospects in ultra-low-dose CT,specific disease diagnosis,and industrial inspection.The application of PCD-CT in spectral CT imaging was reviewed to provide a useful reference for its application in clinical medical diagnosis and industrial applications.

The construction of "Double First-class" has started a new journey of higher education in China. Scientific, reasonable and objective evaluation on universities is the foundation and important guarantee for the construction of first-class universities. On the basis of introducing the main university evaluation system at home and abroad, the selection of representative Chinese and world university evaluation system for comparative study has strong guiding significance for the establishment of first-class university evaluation system. Under the background of "Double First-Class" construction, based on Chinese characteristics, the author puts forward some thoughts and suggestions on perfecting the university evaluation system in China.

Objective Knowledge-motivation-psychological model was set up and tested through structural equation model to provide evidence on HIV prevention related strategy in Men who have Sex with Men (MSM).Methods Snowball sampling method was used to recruit a total of 550 MSM volunteers from two MSM Non-Governmental Organizations in Urumqi,Xinjiang province.HIV prevention related information on MSM was collected through a questionnaire survey.A total of 477 volunteers showed with complete information.HIV prevention related Knowledge-motivationpsychological model was built under related experience and literature.Relations between knowledge,motivation and psychological was studied,using a ‘structural equation model’ with data from the fitting questionnaires and modification of the model.Results Structural equation model presented good fitting results.After revising the fitting index:RMSEA was 0.035,NFI was 0.965 and RFI was 0.920.Thereafter the exogenous latent variables would include knowledge,motivation and psychological effects.The endogenous latent variable appeared as prevention related behaviors.The standardized total effects of motivation,knowledge,psychological on prevention behavior were 0.44,0.41 and 0.17 respectively.Correlation coefficient of motivation and psychological effects was 0.16.Correlation coefficient on knowledge and psychological effects was-0.17 (P＜0.05).Correlation coefficient of knowledge and motivation did not show statistical significance.Conclusion Knowledge of HIV and motivation of HIV prevention did not show any accordance in MSM population.It was necessary to increase the awareness and to improve the motivation of HIV prevention in MSM population.

Objective To explore the protective effects of schisandrin B (Sch B) on hypoxia injury induced by cobaltous chloride (CoCl2) in human proximal renal tubular epithelial (HK-2) cells, and the possible mechanism thereof. Methods HK-2 cells were randomly assigned to four groups:control group (Con, cells were untreated), CoCl2 group (CoCl2, cells were treated with 600μmol/L CoCl2 for 24 h), Sch B pretreat group (CoCl2+Sch B, cells were pretreated with 1μmol/L and 10μmol/L Sch B for 2 h) and Sch B group (Sch B, cells were treated with 1μmol/L and 10μmol/L Sch B for 2 h). CCK-8 kit was used to detect the cell viability of four groups. Flow cytometry was used to detect the apoptotic rate of four groups. The protein expression of hypoxia-inducible factor 1α(HIF-1α) was assessed by Western blot assay. The expressions of HIF-1α and inducible nitric oxide synthase (iNOS) mRNA were determined by RT-PCR. Results Compared with the control group, after treated with 600 μmol/L CoCl2, the cell viability was decreased, and the apoptosis was increased, the expressions of HIF-1α and iNOS mRNA were up-regulated in HK-2 cells. There was no significant difference in the expression of HIF-1α mRNA between control group and CoCl2 group. Compared with the CoCl2 group, after pretreated with 1μmol/L and 10μmol/L Sch B, the cell viability was increased and the apoptosis was decreased, the expressions of HIF-1α and iNOS were down-regulated in HK-2 cells. There were no significant differences in the cell viability and apoptotic rate between control group and Sch B group. Conclusion Pretreatment with Sch B can reduce the apoptosis of HK-2 cells by inhibiting the expression of HIF-1α and iNOS mRNA, which shows protective effects on hypoxia injury.

OBJECTIVETo generate a mouse model of chronic hepatitis B (CHB) infection by performing in vivo transduction of hepatitis B virus (HBV) covalently closed circular (ccc)DNA.

METHODSNude mice were injected with HBV cccDNA at doses of 1.5, 1.0 or 0.5 mug/ml. A control group was generated by giving equal injection volumes of physiological saline. The serum levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) on post-injection days 1 and 3, weeks 1-6, 8 and 10 were assayed by reflection immunoassay. At post-injection week 10, all animals were sacrificed and liver tissues were collected. Copies of HBV DNA in serum and liver tissue were detected by real-time PCR. HBV antigens in liver tissue were detected of by immunohistochemistry. Pathological analysis of liver tissue carried out with hematoxylin-eosin staining. Linear correlation of data was determined by statistical analysis.

RESULTSHBsAg and HBeAg were detected in sera from all three groups of cccDNA-injected mice staring at post-injection day 1 and lasting through week 10. The levels of HBsAg over the 10-week period showed two patterns of increase-decrease;the lowest level was detected at week 4 and the highest level was detected at week 8. In contrast, the levels of HBeAg over the 10-week period showed three patterns of increase-decrease; the lower levels were detected at weeks 2 and 4 and the higher levels at weeks 3 and 6. HBV DNA copies in liver tissues showed a cccDNA dose-dependent descending trend over the 10-week study period (1.5 mug/ml:1.14E+07 ± 6.51E+06 copies/g, 1.0 mug/ml:9.81E+06 ± 9.32E+06 copies/g, and 0.5 mug/ml:3.72E+06 ± 2.35E+06 copies/g; Pearson's r =0.979). HBV DNA copies in sera showed the pattern of 1.0 mug/ml cccDNA more than 1.5 mug/ml cccDNA more than 0.5 mug/ml cccDNA, and in general were higher than those detected in the liver tissues. Liver tissues from all cccDNA-injected mice showed positive immunohistochemistry staining for both HBsAg and HBeAg. HE staining showed that the liver tissues of all cccDNA-injected mice had severe fatty and vacuolar degeneration and less obvious structure of liver lobules (compared to the liver tissues from control mice).

CONCLUSIONThe CHB mouse model successfully established in this study by in vivo transduction of HBV cccDNA may represent a useful tool to study the pathogenic mechanisms and potential antiviral treatments of human CHB.

Animals ; DNA, Circular ; administration & dosage ; DNA, Viral ; administration & dosage ; Disease Models, Animal ; Hepatitis B Surface Antigens ; blood ; Hepatitis B e Antigens ; blood ; Hepatitis B virus ; genetics ; physiology ; Hepatitis B, Chronic ; virology ; Male ; Mice ; Mice, Nude ; Transduction, Genetic ; Virus Replication

Objective To analyze the expression of Galectin-3 in thyroid follicular tumors and its clinical significance in differential diagnosis between benign and malignant thyroid follicular tumor.Methods The expression of Galectin-3 in 120 cases of thyroid follicular carcinoma and 80 cases of thyroid follicular adenoma was detected by immunohistochemical technique.Results The expression rate of Galectin-3 in thyroid follicular carcinoma was significantly higher than that in follicular adenoma(84％ vs 19％,P ＜ 0.01).Strong positive expression of Galectin-3 was found in 40％ cases of thyroid follicular carcinoma and no case of thyroid follicular adenoma.Conclusions The expression of Galectin-3 can be regarded as an important parameter for differential diagnosis between benign and malignant thyroid follicular tumor.

Objective To explore the clinicopathologic characteristics and treatment of medullary thyroid carcinoma(MTC).Methods The data of 42 cases of MTC admitted to Fujian Medical University Provincial Clinical College from Jan 1995 to Feb 2010 were retrospectively analyzed.Surgery was performed in all the 42 cases.All were proved to be MTC by pathology.Results Surgery was performed in all the 42 cases.All were proved to be MTC by pathology.The lymph node metastasis rate was 76.19％ (32/42).The central lymph node metastasis rate was 61.90％ (26/42).All the 42 cases were followed up for 1 to 502 months with 102 months as the median.35 cases(83.33％)were followed up for more than 5 years and the 5-year overall survival rate was 85.71％ (30/35).Death occurred in 5 cases.Conclusions The lymph node metastasis rate of MTC is high.The treatment should be based on the principle of radical resection.Total thyroidectomy should be recommended to treat primary tumor.Lymph node dissection should be as thorough as possible.Central compartment neck dissection should be done in all cases.

Objective To summarize the experience of diagnosis and treatment strategy of pancreatic injury.Methods The data of 36 cases of pancreatic injurics admitted to Fujian Medical University Provincial Clinical College from 1990 to 2011 were analyzed retrospectively.Results 14 cases(39％)were diagnosed preoperatively,and the other cases were diagnosed during the laparotomy.2 cases underwent non-surgical treatment.34 cases underwent surgical treatment,among whom 23 cases underwent pancreatic debridement and drainage,6 cases underwent distal pancreatectomy(4 cases undergoing distal pancreatectomy plus splenectomy included),4 cases underwent distal Roux-Y pancreajejunostomy plus proximal pancreas closure,and 1 case underwent pancreatoduodenectomy.31 cases (86％) were cured,and 5 cases died (14％).Conclusions Most of the pancreatic injury is diagnosed through laparotomy.Surgical opcration is the main approach to treat pancreatic injury.Nonsurgical treatment is primarily limited to grade Ⅰ and Ⅱ pancreatic injury without obvious peritonitis,major pancreatic duct injury,and associated injuries.Surgical procedure should be selected based on the grading scale of pancreatic injury,associated injuries and overall conditions of the patient.

Objective To evaluate the real-time genotyping and quantitative PCR(RT-GQ-PCR)method by comparing it with direct sequence analysis and the multiplex-PCR method.Methods RT-GQ-PCR,direct sequence analysis and the multiplex-PCR method were used to detect HBV genotypes of 113 patient samples with HBV-DNA positive.ResultsThe detection rate of RT-GQ-PCR and direct sequence analysis was 100%,and the multiplex-PCR is 94.69%.The concordance between RT-GQ-PCR and the multiplex-PCR is perfect(Kappa value =0.915),and the consistency of RT-GQ-PCR and direct sequence analysis is pretty good(Kappa value = 0.742),specially at detecting single genotype.Twenty-eight samples with genotypes B and C dual infections were detected by RT-GQ-PCR,but only 19 samples by the multiplexPCR and 13 samples by direct sequence analysis.Conclusion The RT-GQ-PCR is convenient,rapid and accurate in HBV genotyping,especially more sensitive than direct sequence analysis and the multiplex-PCR for detecting dual genotypes.The method is applicable for large-scale epidemiological study.

Objective To analyze the characteristics and hepatotropism of this negative element HBVnt453-250 sequence.Methods pHBv453-250,pHBV250-453.plucHBV453-250 and plucHBV250-453 were constructed,with luciferase and enhanced green fluorecence protein(EGFP)gene as the reporter gene,respectively.After transfection of HepG2 cells with these plasmids,luciferase assays,real-time PCR and western blot assays were used to detect the gene transcription and expression level.The SV40 promoter of pGL3 control and pHBV453-250 were replaced by the cytomegalovirus early promoter,resulting in plasmids pCMVcontrol(luc)and pCMV453-250(luc).Results Compared with pHBV453-250,the mutant plasmids.with the inhibitory element inserted in difierent site or inverted orientation.exerted similar downregulation of Juciferase gene transcription and expression.Western blot analysis demonstrated the similar repression when EGFP was used as the reporter gene.By transfeeted to HepG2 cell line,the plasmid pCMV453-250(1UC)could reduce lneiferase activity(36.56%)compared with pCMLcontrol(luc).When the plasmids plueHBV453-250 and plucHBV250-453 were transfected to non-liver cell lines(A549,HeLa),luciferase gene was expressed weakly,compared with that of pGL3control(P＜0.05).Conclusion The inhibitory effect of HBVnt453-250 sequence acted in both orientation-and position-independent manners,and had no promoter selectivity and funotioned in hepatocyte-independent manner.