Objective We performed a diffusion tensor imaging (DTI) study to explore the value of mode of anisotropy (MO) and other DTI-derived indices in assessing white matter fiber damage with mild to moderate Alzheimer disease (AD) patients. Methods This study was a prospective study. From February 2015 to February 2018, 33 patients with mild to moderate AD according to criteria were prospectively recruited as AD group at the First Affiliated Hospital of Wenzhou Medical University. Twenty healthy age-, sex-matched volunteers were recruited as normoal conctrast (NC) group. All subjects were performed by conventional brain MRI and DTI scans. The MO, anisotropic fraction (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AxD) of white matter fibers were obtained from DTI images after TBSS post-processing. The statistical analyses of DTI indices between AD group and NC group were carried out in Functional MRI Software Library software. Results As compared with NC group, we found 1 cluster with significant decrease FA and increase RD in AD group, the affected fibers involving bilateral anterior thalamic radiation, corticospinal tract, cingulate gyrus, hippocampus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, uncinated fasciculus, superior longitudinal fasciculus (P<0.05). The MD value increase(P<0.1) was found to coincide with the decrease of FA and the increase of RD, while no significant increase or decrease in P<0.05. Three clusters of MO increases (P<0.05) accompanying with increases of AxD were found in left anterior limb of internal capsule, bilateral posterior limb of internal capsule, posterior forceps, left centrum semiovale and parietal lobe. Two clusters of MO decreases (P<0.05) accompanying with decreases of FA and increases of RD were found in fornix, forceps, external capsule, centrum semiovale and left frontal lobe. Conclusions The combination of MO with DTI routine tensor indices (FA, RD, MD, AxD) can further reveal the microstructural damage of white matter fibers in AD, especially to crossing-fibers. The abnormalities of MO combined with FA, RD and MD reveal the degeneration of both bundles of crossing-fibers,and the abnormalities of MO combined with AxD reveal that the white matter damage was mainly caused by axon damage of one bundle of cross fibers.

Objective: To investigate the characteristics, temporal trend of silicosis, and provide basis for risk assessment and precise prevention and control of occupational diseases. Methods: Using descriptive statistics to analyze the reported cases of silicosis by SPSS 20.0 software. Reported silicosis cases, the constituent ratio, the incidence age and the working age at onset were analyzed by a linear trend test. Analyzing the variation trends of regional, industry, economic type and enterprise scale distributions by the chi-square trend test. Moreover, using Moran's I method for spatial autocorrelation analysis and trend-surface analysis. Results: (1) During 2006 to 2015, Guangdong province had reported 1, 428 cases of silicosis, mainly gathered in Foshan, Zhongshan, Guangzhou, Shenzhen, which included 1391 male cases accounting for 97.41%. And the average incidence age was 45 (39, 51) . The average working age of onset was 9 (5.5, 15) . In economic type distribution, the private economy took the main part, accounting for 59.1%. In enterprise scale distribution, it was dominated by small and medium enterprises (SMEs) , accounting for 32.4% and 37.3% respectively. In industry distribution, most cases were gathered in materials and mining industry, accounting for 32.1% and 22.9% respectively. (2) The number of silicosis cases, the incidence age and the working age of onset showed a rising trend (P<0.01) . Meanwhile, the constituent ratios of medium-sized enterprises and building materials industry were increasing (P<0.05) . The annual variation trends of regional, economic type and age distributions were not statistically significant (P> 0.05) . (3) The spatial distribution trend showed an inverted U type, which was firstly raised and then declined from south to north and from east to west. The distribution characteristic demonstrated some high-high cluster areas, including Chancheng, Nanhai, Shunde, Panyu, Dongguan, Pengjiang, and Zhongshan. While Wuhua showed a high-low outlier form (P<0.01) . Conclusion Silicosis cases, age and working age of onset were on the rise, as well as the industry and enterprise scale distributions of occupational diseases presented a certain trend in Guangdong province from 2006 to 2015. There were high-high cluster and high-low outlier phenomena in spatial distribution with spatial correlation. Therefore, our work of silicosis epidemic trend and distribution may provide some bases for the occupational disease risk assessment and control.

Objective To discuss the influence of the change in ceiling-mounted shield positions on the radiation doses to the first and second operators during percutaneous coronary intervention.Methods In this study,the entrance surface dose (ESD) rates were measured for the first and second operators at 125 cm and 155 cm height on different ceiling-mounted shield positions separately through transradial approach.Measurements were repeated 20 times for each position and T test was used for statistical analysis of dose rate arithmetic mean values.Results For the first operator,the effective dose values were obtained only on left foot position.The ESD rate values at ceiling-mounted shield position close to patient were higher than that close to operators (t125 =46.9,t155 =4.1,P ＜0.05).For the second operator,the ESD rate values on his foot position,right foot position,left anterior oblique position and right anterior oblique position at ceiling-mounted shield position close to the operator,were higher than that close to the patient separately (t125 =11.9,24.4,11.2,2.7,t155 =16.1,2.8,14.4,28.8,P ＜ 0.05).The ESD rate values on head position,left foot position,left head position at ceiling-mounted shield position close to the operator,were lower than that close to the patient (t125 =-4.3,-2.4,-80.4,t155 =-10.2,-6.7,-152.6,P ＜ 0.05).Conclusions The change in the ceiling-mounted shield positions gave rise to change in radiation dose to the operators.The changes in radiation doses caused by the changes in ceiling-mounted shield positions are different in various angiographic positions.Ceiling-mounted shield should be used in a reasonable way in agreement with different positions in percutaneous coronary intervention so as to effectively reduce operators radiation dose.

Objective To investigate the long-term effects of propofol postconditioning on cerebral ischemia-reperfusion (I/R) injury in rats.Methods One hundred and forty-four healthy male SD rats,aged 7-8 weeks,weighing 250-280 g,were equally and randomly divided into 4 groups:sham operation group (group S),I/R group,propofol postconditioning group (group P) and intralipid group (group I).The animals were anesthetized with intraperitoneal 10％ chloral hydrate 300 mg/kg.Focal cerebral ischemia was induced by occlusion of middle cerebral artery for 60 min using a nylon thread with a rounded tip which was inserted into internal carotid artery in groups I/R,P and I.Two hour infusion of propofol was started at 20 mg· kg- 1· h- 1 immediately after the onset of reperfusion in group P,while the equal volume of normal saline was given instead in S and I/R groups,and 10％ intralipid was given instead in group I.Five rats in each group were chosen on day 1,14 and 28 after operation for assessment of neurological behavior and detection of cerebral infarct volume.Six rats in each group were chosen to perform Morris water maze test at day 9 and 23 after operation for 6 consecutive days.Five rats in each group were sacrificed on day 1,14 and 28 after operation and the hippocampal tissues were isolated for determination of the expression of GluR1-containing AMPA (GluR1-AMPA) receptor and GluR1-AMPA receptor in cell membrane.The ratio of GluR1-AMPA receptor in cell membrane/GluR1-AMPA receptor was calculated.Results Compared with group S,neurological behavior scores and the number of animals' swimming across the platform were significantly decreased,cerebral infarct volume was significantly enlarged,escape latency was significantly prolonged,and ratio of GluR1-AMPA receptor in cell membrane/GluR1-AMPA receptor was significantly increased ( P ＜ 0.05),while no significant change in the expression of GluR1-AMPA receptor was found in I/R group ( P ＞0.05).Propofol postconditioning inhibited cerebral I/R-induced changes mentioned above ( P ＜ 0.05).Conclusion The brain protection against focal I/R injury by propofol postconditioning can last for 28 days after operation and the inhibition of trafficking of GluR1-AMPA receptor from cytoplasm to cell membrane may contribute to this long-term brain protection.

Objective To investigate MRI signal features and MRI appearances of patients with advanced stage in polyacrylamide hydrophilic gel injection for facial plasty.Methods In this study,MRI of 11 cases with 23 polyacrylamide hydrophilic gel injection of facial plasty for 6 to 10 years were retrospectively reviewed.All images were acquired with GE 3.0T MR imaging unit.MR sequences,including FSE T1WI,FSE FS T2WI,and STIR were applied with 8-channel brain coil.MRIs sliced through the maxillofacial region in the transverse,coronal and sagittal planes.Results In 11 cases of 23 polyacrylamide hydrophilic gel injection,there were different degrees of capsule rupture and induration in 6 polyacrylamide hydrophilic gel injection,and the images showed sporadic callosities such as subcutaneous nodules and nodules in glands or muscles ; hydrogel migration in 8 polyacrylamide hydrophilic gel injection.Secondary deformity occured in 80 ％ cases,in which the most cases were induced by hydrogel migration.Conclusions Magnetic resonance imaging can make clear of the type of rupture and the distribution leakage of polyacrylamide hydrophilic gel for facial plasty and it is an ideal approach for advanced patients with polyacrylamide hydrophilic gel injection for follow-up.