Objective To investigate the image quality difference of the virtual monochromatic spectral(VMS) images synthesized from fast kilovoltage switching and dual-source dual-energy CT for a given radiation dose. Methods A plurality of disposable syringes containing 15 mg/ml iodine contrast agent and saline were placed on the surface of the male anthropomorphic phantom consisting ofhead neck and torso, GE HD750 gemstone spectral imaging and Siemens Somatom Definition Flash dual energy CT protocols were performed on the phantom for a same dose(volume CT dose index 6.52 mGy), and VMS images (40, 60, 70, 80, 100, 120, 140 keV) were reconstructed and obtained(VMSkV switching and VMSdual-source image), respectively. The objective image noise, iodine signal noise ratio(SNR), iodine contrast noise ratio (CNR) and CT values were measured. The results were analyzed using the paired t test and ANOVA. Results All VMS iodine CT values were gradually decreased with the increasing of keV , and iodine CT values on VMSdual-source images were greater than on VMSkV switching images(P<0.05), VMSkV switching iodine CT values in descending order from the head , chest, abdomen at less than 100 keV,while most VMSdual-source iodine CT values were highest on chest(P<0.05). VMSdual-source and VMSkV switching image noise were highest at 40 keV and successively raised from the head, chest , abdomen. VMSkV switching image noise gradually decreased with the increase of keV in the range of 40 to 70 keV , gradually increased up to the trough after 70 keV from 80 keV gradually decreased, while VMSdual-source image noise was lowest at 70 keV or 80 keV , and then with the keV increased gradually increased. Image noise on VMSkV switching images in the range of 40 to 100 keV were higher than that on VMSdual-source images and lower in the range of 100 to 140 keV at most part(P<0.05). VMSdual-source and VMSkV switching iodine SNR were highest at 40 keV or 60 keV,SNR on VMSdual-source images are greater than on VMSkV switching images except 40 keV images on head and abdomen(P<0.05) . VMSdual-source and VMSkV switching iodine CNR were highest at 60 keV,CNR on VMSdual-source images are greater than on VMSkV switching images except 40 keV images on head 100 keV and 120 keV on abdomen(P<0.05).SNR and CNR decreased from the head, chest, abdomen (P<0.05). Conclusion VMS images synthesized from fast kilovoltage switching and dual-source dual-energy CT have different image quality performance at most keV and body parts, but VMS imaging at approximately 70 keV yielded lower image noise, and at approximately 60 keV yielded highest SNR and CNR.

Objective To survey the employment intention of medical students in different universities in China.Methods A total of 1354 fourth-year or above medical students from 6 medical universities in China were selected for survey by random cluster sampling.A self-designed questionnaire was used to investigate the basic information of students and their employment intention.Results Overall 46.5％ (620/1333) of all students choose cities in economically-developed region as their desired working sites.45.5 ％ (363/797) of students studying in 4 Shanghai medical universities and 34.5％ (185/536) in other 2 non-Shanghai universities would first choose their original cities as working sites,respectively.81.3％ (1078/1326) of students preferred working in large public hospital,especially for those studying for higher degrees (88.0％,581/660).51％ of undergraduates expected 4000 RMB as monthly pay for graduation.Male students (54.6％,332/608) expected more income than female (47.9％,335/700),graduates (57.9％,377/651) expected higher payment than undergraduates (44.1％,290/657).Conclusion The survey shows that medical students in China mainly prefer cities and large public hospitals as working sites for their career development.

Objective To evaluate the pathogenesis and disease progression by detecting the expression of Serum High mobility group protein 1 (HMGB1) and TLR2 in monocytes of patients with systemic lupus erythematosus (SLE).Methods Forty patients with SLE were selected randomly,20 patients were in active disease group and others were in stable disease group.The expression of HMGB1 in the serum of these cases were detected by enzyme linked immunosorbent assay (ELISA) and TLR2 on CD14+ monocytes in the peripheral blood were detected by FCM.The correlation between these indexes and clinical,laboratory indexes about SLE were analyzed using one-way ANOVA,and Kruskal-Wallis test.Results The expression levels of HMGB-1 in serum was [(48.9±11.3) μg/L] in the active group,while that was [(14.8±1.9) μg/L] in the stable group was,and [(13.5±3.6) μg/L] in the control group.HMGB1 in the active SLE group was significantly higher (P＜0.05) when compared with that of the stable and control group.The expression of TLR2 in the peripheral blood mononuclear cells was [(96.7±1.3)％] in the active group,[(83.5±9.1)％] in the stable group,and [(83.3±9.9)％] in the control group TLR2 in the active SLE group was up-regulated when compared with the stable and control groups (P＞0.05).There were positive correlation between the serum levels of HMGB1and TLR2 in the peripheral blood mononuclear cells (r=0.551,P＜0.05).Conclusion The expression levels of HMGB-1 in serum and the expression of TLR2 in peripheral blood mononuclear cells may participate in the pathological processes of SLE.

Objective To investigate the effects of hyperbaric oxygen (HBO) therapy following spinal cord injury (SCI) and its mechanisms. Methods Thirty Sprague-Dawley rats were randomly divided into two groups after inducing SCI models using a modified version of Allen's method. The HBO group received HBO treatment 2 h after the procedure and were then treated 100 min every day for 5 consecutive days. All the rats were evaluated 1 h before the operation, and 1 h, 10 d and 20 d afterward using BBB scores and inclined plane experiments. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured. At twenty days, all the rats were sacrificed and their spinal cords were examined pathologically using HE staining. Results Average BBB scores and climbing ability in the HBO group were better than in the control group at the 10th and 20th day after the operation. Compared to the control group, SOD increased significantly and MDA decreased significantly in the HBO group at the 2nd and 5th day after the operation. There was less cystic degeneration of the spinal cord in the HBO group. Conclusions HBO demonstrated a positive effect after SCI. Oxygen free radicals might be one of the mechanisms for the better recovery.

Objective: To study the effects of chromium on glucose and lipid metabolism and gene expression in diabetic rats.Methods: Male Wistar rats were assigned to three groups:normal control(NC), alloxan-induced diabetic control group(DM), and DM with chromium supplementation group(DM+Cr). Cr 200 ?g/(kg bw?d) was supplemented orally for 60 days. At the end of the treatment, the blood glucose, lipid and serum insulin were measured, and the changes in gene expression among three groups were studied by mRNA differential display technique.Results: Blood glucose in DM+Cr group decreased significantly than that before experiment. The levels of serum TG, TC, LDL-C and AI in DM+Cr group were lower than those of DM group, while the serum HDL-C levels were higher. Serum insulin was not improved obviously in DM+Cr group. 11 cDNA fragments larger than 400 bp expressed differences in skeletal muscles between DM+Cr group and DM group and were isolated, 4 of which expressed higher in DM+Cr group, while the rest expressed higher in DM group.Conclusion: Chromium supplementation could partially improve the disorders of glucose and lipid metabolism, and have an impact on some gene expression in diabetic rats, which may contribute to the regulating effects on its disorders of metabolism.

Objective To investigate the effect of percutaneous vertebroplasty and kyphoplasty (PKP) on bone density and serum leptin in patients with osteoporotic thoracolumbar compression fractures. Methods One hundred and two patients with osteoporotic thoracolumbar vertebral compression fractures and 100 cases of healthy control were treated with PKP surgery. The serum leptin and adiponectin, and the bone mineral density of the lumbar spine were determined. Results patients Levels of the serum leptin and adiponectin in patients with osteoporotic thoracolumbar vertebral compression fracture were significantly higher than those with non osteoporotic fracture patients (P < 0.05). One month post-PVP, the levels of serum leptin and adiponectin in the two groups were significantly decreased (P < 0.05). postoperative group of The lumbar bone density at 1 month post-operation was is significantly higher than that before operation in each group (P < 0.05, respectively), with no significant difference between the two groups. The levels of serum leptin and adiponectin were negatively correlated with the bone mineral density (BMD) (P < 0.05). Conclusions tLevels of serum adiponectin and leptin were both increased in osteoporotic or non bone osteoporosis thoracolumbar vertebral compressor fractures. The percutaneous vertebroplasty forming operation could effectively reduce the serum level of leptin and adiponectin, and improve the bone mineral density of the lumbar vertebrae.

Objective To examine the short-and middle-term efficacy and refracture rate in patients with thoracolumbar fracture having percutaneous kyphoplasty (PKP) and determine their correlation with the severity of osteoporosis.Methods A retrospective analysis was conducted on 247 patients with thoracolumbar fracture undergone PKP from January 2008 to February 2014.Mean age of the patients (94 males and 153 females) was 63.2 years (range,50-81 years).Ground-level falls occurred in 119 patients,traffic injuries in 72 patients and high falls in 56 patients.The patients were assigned to osteopenia group and osteoporosis group based on the preoperative bone mineral density.Visual analogue score (VAS),Roland-Morris disability survey scale (RDQ),vertebral compression rate,kyphotic Cobb angle and refracture rate were recorded before and after operation.Efficacy in correlation with the severity of osteoporosis was evaluated.Results Mean duration of follow-up was 24.3 months (range,18-36 months).Three days after operation,VAS descended from (7.7 ± 2.1) points to (4.3 ± 1.1) points in osteopenia group and from (7.7 ± 2.0) points to (4.2 ± 1.5) points in osteoporosis group (P ＜ 0.05);RDQ descended from (21.2 ± 1.5) points to (10.4 ± 2.5) points in osteopenia group and from (20.8 ± 1.9) points to (11.2 ± 1.7) points in osteoporosis group (P ＜ 0.05);rate of vertebral body compression descended from (42.2 ± 10.5) ％ to (3.2 ± 0.5) ％ in osteopenia group and from (46.2 ± 12.7) ％ to (2.9 ± 0.8) ％ in osteoporosis group (P ＜ 0.05);kyphotic Cobb angle descended from (21.2 ± 9.5) ° to (7.2 ±2.4) °in osteopenia group and from (23.1 ± 8.9) ° to (7.1 ± 2.6) ° in osteoporosis group (P ＜ 0.05).Three years after operation,all the parameters remained better than these before operation,with the value higher in osteoporosis group than in osteopenia group (P ＜ 0.05).Rate of refracture was higher in osteoporosis group after operation,compared to that in osteopenia group (P ＜ 0.05).Conclusions The clinical short-term result is satisfactory,but refracture rate is increased with the osteoporosis aggravation.Targeting osteoporosis therapy is important to obtain a better mid-term results.

Objective To compare the differences of pulmonary nodule detection rates between iterative reconstruction (sinogram affirmed iterative reconstruction,SAFIRE)algorithm and filtered back projection (FBP) algorithm in chest CT, and to evaluate the detection accuracy.Methods Three groups of tube voltage values of 80,100,and 120 kV were defaulted on the new dual-source CT,with automatic mAs care dose 4D technology, the chest phantom with simulated pulmonary nodules was scanned, then the images were reconstructed with FBP and SAFIRE (grade 1-5 ),respectively. The detection rates of simulated pulmonary nodules in the chest CT images reconstructed of SAFIRE (grade 1-5 )and FBP were compared, and their diameters and CT values were measured.Results With the same tube voltage, no significant difference was found in the detection rate of simulated pulmonary nodules between SAFIRE (grade 1-5 )and FBP (P>0.05 ), the diameter deviation of simulated nodules of SAFIRE (grade 3 )was less than FBP, and the difference in the average CT value of the simulated nodules between SAFIRE (grade 3)and FBP was not statistically significant (P>0.05);the simulated nodule detection rate of 100 kV was equivalent to the detection rate of 120 kV,the simulated nodule (-800 HU and 3 mm )detection rate of 80 kV was less than that of 120 kV;as the tube voltage reduced,or simulated nodule diameter decreased,or the density of simulated nodule reduced,the nodule’s diameter deviation was increased. Conclusion Compared with FBP,the capabilities of SAFIRE in pulmonary nodule detection in different densities and different sizes are same,and SAFIRE algorithm is helpful for accurate displaying of pulmonary nodules,and it can be used for low-dose CT lung cancer screening program.

Objective To evaluate the accuracy and efficiency of the Monte Carlo software in measuring the radiation dose to the patients who received the CCTA (Coronary Computed Tomography Angiography) examination.Methods A anthropomorphic chest phantom underwent CCTA using three scan parameters (tube voltage 80 kV,100 kV and 120 kV).Computer Software ImpactDose 2.0 was used to compute the chest organ dose on the basis of the three groups tube voltage CT scan characteristic,and the stimulation results of ImpactDose 2.0 software was verified by use of anthropomorphic phantom thermoluminescence dosimeter experiment method.Results For all the measured organs except for lung,the absorbed organ dose and effective dose of three groups of tube voltages of CCTA measured by the InpactDose 2.0 was lower than those as measured by anthropomorphic phantom study.The relative error of both methods was within ± 50％.Conclusions Monte Carlo software can be used to estimate the levels of radiation dose during CCTA examination with a tolerable error within the acceptable range.

To study the implementation of the epidemic prevention by the authorities of the concession and late Qing dynasty through investigation of the prevention and treatment of pestilence in Shanghai from 1872 to 1911, this paper analyzes the issues concerning municipal administration, inspection and disinfection, food sanitation, vaccination, regulatory legislation and health promotion, etc. The experiences are summarized in the study. The lessons drawn from what the concession authority did to prevent pestilence imply that the implementation of health promotion should be carried out according to the variation of the time, location and population, and that traditional Chinese medicine should be involved in the prevention and treatment of pestilence.