Objective To investigate the dosimetric properties of PTW 60019 synthetic diamond detector in small photon beams.Methods A PTW 60019 synthetic diamond detector was tested under 6 and 10 MV photon beams,respectively.Linearity with dose,dose rate dependence and off-axis ratio were measured and compared to those measured by an IBA SFD.Percentage depth doses were measured and compared to those measured by an IBA SFD and a PTW 31010 semiflex chamber.Total scatter factors were measured and compared to those measured by an IBA SFD and a PTW 31016 PinPoint chamber.Results The dose response of a PTW 60019 synthetic diamond detector showed a good linear behavior as a function of dose,with observed deviations below 0.2％ over a dose range from 100 to 1 000 MU.The dose rate response was almost independent,with deviations below 0.2％ in the dose rate range from 37 to 614 MU/min.For the fields of 20-100 mm in diameter,there were dose differences in percentage depth doses within 1％ as compared to an IBA SFD and a PTW 31010 semiflex chamber.For the 10 mm diameter field,the differences were up to 5.8％ in the build-up region.Off-axis ratios measurements showed a good agreement among the involved detectors (＜ 1％).The higher differences appeared in the penumbra region.A good agreement was also found in terms of total scatter factor measurements for the related detectors.Conclusions The observed dosimetric properties of the PTW 60019 synthetic diamond detector indicate that it is a suitable candidate for small photon beam dosimetry.

Objective To discuss the effects and influence of preoperative and postoperative adjunctive intravitreal conbercept in 23G vitrectomy for proliferative diabetic retinopathy (PDR).Methods A retrospective research was performed on 42 PDR eyes from January 2015 to February 2016 in the Second Affiliated Hospital of Nanchang University,who received either intravitreal 0.05 mL conbercept injection 7 days before 23G vitrectomy (group A,n =22) or intravitreal 0.05 mL conbercept injection at the end of 23 G vitrectomy (group B,n =20).The operative time,postoperative vitreous hemorrhage (VH),intraoperative and postoperative other differences of clinical indicators and postoperative best-corrected visual acuity (BCVA) between the two groups were compared.Results The average operation time,intraoperative electric coagulation hemostasis rate,iatrogenic hiatal incidence and intraoperative hemorrhage rate of group A were lower than those of group B (all P ＜ 0.05).BCVA at 6 months after surgery did not differ significantly between two groups (P ＞ 0.05),but the difference was statistically significant between pre-operation and post-operation (P ＜ 0.05).The incidences of early (≤ 1 month) postoperative VH were 18.2％ (4 eyes) and 15.0％ (3 eyes) in group A and B,respectively (P ＞ 0.05).The incidences of later (＞ 1 month) postoperative VH were 27.3％ (6 eyes) and 0 in group A and B,respectively,the difference was statistically significant (P ＜0.05).The percentages of reoperation were 13.6％ (3eyes with postoperative VH) and 10.0％ (2 eyes with traction retinal detachment) respectively in group A and B.The average times of supplementary laser photocoagulation were (2.3 ± 1.0) times and (1.4 ±0.6) times in group A and B,respectively in follow-up period (P ＜ 0.05).Conclusion The adjunctive use of intraoperative intravitreal injection of conbercept can prevent effectively postoperative VH and decrease conveniently the time of supplementary laser photocoagulation in 23G vitrectomy for PDR,as well as the preoperative adjunctive use can decrease the operation time,intraoperative complications and incidences of early postoperative VH.

BACKGROUND: Previous studies have reported that femoral head finite element models are mostly modeled with single or few samples for specific biomechanical research, but there is little research on model stability. OBJECTIVE: To compare the models of normal femoral head and osteonecrosis of the femoral head with multiple samples, and to analyze the accuracy and stability of the models through the comparison of stress distribution and mechanical parameters, so as to provide mechanical basis for prevention and treatment of collapse of osteonecrosis of the femoral head. METHODS: Totally 20 sides uncollapsed of osteonecrosis of the femoral head one year of non-surgical treatment were selected as the experimental group, and the healthy side of 20 patients with unilateral osteonecrosis of the femoral head were set as the normal group. The CT data of the femoral head were collected to establish the finite element model. The stress distribution of normal femoral head and osteonecrosis of the femoral head, the maximum equivalent stress and the maximum total deformation at the weight-bearing area of the femoral head were observed and compared. This study was approved by the Medical Ethics Committee of Wangjing Hospital of China Academy of Chinese Medical Sciences. Patients signed the informed consent. RESULTS AND CONCLUSION: (1) The finite element models of normal proximal femur, non-necrotic proximal femur and necrotic bone were established. The number of elements and nodes were 502 568±114 196, 692 608±154 678; 449 954±125 824, 623 311±171 401; 19 133±13 167, 27 577±19 131, respectively. (2) When the load was set by simulating one-foot standing position, the cloud image showed that when 2.5 times body weight applied to the weight-bearing area of the femoral head; the surface stress of the weight-bearing area of the normal femoral head was uniform. The stress was uniformly distributed in the femoral head along the stress trabeculae, and the calcar femorale bears the most. The stress concentration area appeared on the surface of the weight-bearing area and the necrotic area of osteonecrosis of the femoral head. The stress was scattered and distributed on the inner and outer sides of the femoral neck and the femoral head of osteonecrosis of the femoral head produced more deformation than the normal femoral head. (3) The maximum total deformation of the weight-bearing area of the osteonecrosis of the femoral head and the normal femoral head was (4.14±1.31) mm and (1.36±0.22) mm and the maximum equivalent stress was (1.94±0.77) MPa and (0.75±0.19) MPa, respectively, and with statistically significance (P < 0.05). Moreover, two groups of data tend to be concentrated and the models are stable. Through the comparison of multi-sample normal femoral head and osteonecrosis of the femoral head, the CT gray-assigned method reflects the actual mechanical properties of osteonecrosis of the femoral head, and has good accuracy and stability.

The impact of maternal air pollution exposure on offspring health has received much attention. Precise and feasible exposure estimation is particularly important for clarifying exposure-response relationships and reducing heterogeneity among studies. Temporally-adjusted land use regression (LUR) models are exposure assessment methods developed in recent years that have the advantage of having high spatial-temporal resolution. Studies on the health effects of outdoor air pollution exposure during pregnancy have been increasingly carried out using this model. In China, research applying LUR models was done mostly at the model construction stage, and findings from related epidemiological studies were rarely reported. In this paper, the sources of heterogeneity and research progress of meta-analysis research on the associations between air pollution and adverse pregnancy outcomes were analyzed. The methods of the characteristics of temporally-adjusted LUR models were introduced. The current epidemiological studies on adverse pregnancy outcomes that applied this model were systematically summarized. Recommendations for the development and application of LUR models in China are presented. This will encourage the implementation of more valid exposure predictions during pregnancy in large-scale epidemiological studies on the health effects of air pollution in China.

MicroRNA (miRNA or miR) is a class of highly conserved endogenous non-coding RNA of 21~25nt, which is widely existed in organisms. Currently, miRNA has been proven to be associated with cardiovascular diseases in clinical research, but it has not been reported in the field of forensic medicine. This paper highlights recent findings about miRNA and its application in cardiovascular diseases, and the application aspect of miRNA in sudden cardiac death in forensic science.

Brain natriuretic peptide (BNP), a natriuretic peptide hormone, is mainly secreted by cardiomyocytes when they are pulled by mechanical force. BNP acts to increase natriuresis and decrease vascular resistance, thereby decreasing blood volume, systemic blood pressure and afterload. It is not only the main indicators of cardiac function which is widely used in clinical, recent studies have also shown that it has a very important value in identifying sudden cardiac death(SCD). However, the exact expression of the regulation mechanism is still unknown. This paper reviewed the structure, expression of the regulation mechanism of BNP, and the application progress in clinical and forensic.

Objective To assess the performance of PET-CT in pulmonary carcinoid and to evaluate the efficacy of lymph node metastasis.Methods We retrospectively collected the data of 33 patients with primary pulmonary carcinoid in our center between November 2008 and March 2017.The results of PET-CT were analysed and the relationship among pathological sub-type, tumor size and SUVmax was compared.Results Thirty-three patients had a diagnosis of carcinoid tumor, typical in 10 patients and atypical in 23 patients.The major axis of the tumor was positively correlated with the SUVmax value (P<0.001), and the mean SUVmax of the atypical carcinoid was higher than that of the typical carcinoid(11.27 vs 3.54).The major axis of the tumor was controlled.One-way covariance analysis suggested that the pathological subtype was related to SUVmax(P=0.012).Overall, PET-CT had a sensitivity of 66.7％(95％CI: 12.5％-98.2％) and specificity of 90.9％(95％CI:83. 0％-95.5％).Conclusion Atypical carcinoids showed higher SUVmax than typical carcinoids, but the PET-CT perform-ance of lung carcinoids is not specific.There was a high specificity in evaluating lymph node metastasis.

Objective To reveal the mechanism of action of AS-Ⅳ on HepG2 cells based on molecular dynamics simulation and experimental evaluation. Methods We constructed a "drug-disease" network pharmacological map, analyzed the core genes of astragaloside Ⅳ (AS-Ⅳ) in HCC, screened key signaling pathways, and established a "drug-target" molecular dynamics model. In vitro assay was used to detect migration, proliferation and invasion abilities. Flow cytometry and qRT-PCR were used to detect the effect of AS-Ⅳ on the cell cycle and apoptosis, and the expression of core gene of HepG2. Results The core target of AS-Ⅳ acting on HCC was VEGFA. Compared with the control group, the high concentration of AS-Ⅳ significantly inhibited the migration, invasion and proliferation of HepG2 cells, blocked the metastasis of HepG2 cells from G₁ to G₂ phase, promoted their apoptosis, down-regulated VEGFA expression and up-regulated TGF-β1 expression. Conclusion AS-Ⅳ may inhibit the proliferation of hepatocellular carcinoma cells through multi-target and multi-pathway.

Background and objective Localization of pulmonary ground glass small nodule is the technical dif-ficulty of minimally invasive operation resection. The aim of this study is to evaluate the value of intraoperative computed tomography (CT)-guided localization using a hook-wire system for small ground glass opacity (GGO) in minimally invasive resection, as well as to discuss the necessity and feasibility of surgical resection of small GGOs (<10 mm) through a minimally invasive approach.MethodshTe records of 32 patients with 41 small GGOs who underwent intraoperative CT-guided double-thorn hook wire localization prior to video-assisted thoracoscopic wedge resection from October 2009 to October 2013 were retrospectively reviewed. All patients received video-assisted thoracoscopic surgery (VATS) within 10 min atfer wire localiza-tion. hTe effcacy of intraoperative localization was evaluated in terms of procedure time, VATS success rate, and associated complications of localization.Results A total of 32 patients (15 males and 17 females) underwent 41 VATS resections, with 2 simultaneous nodule resections performed in 3 patients, 3 lesion resections in 1 patient, and 5 lesions in a patient. Nodule di-ameters ranged from 2 mm-10 mm (mean: 5 mm). hTe distance of lung lesions from the nearest pleural surfaces ranged within 5 mm-24 mm (mean: 12.5 mm). All resections of lesions guided by the inserted hook wires were successfully performed by VATS (100% success rate). hTe mean procedure time for the CT-guided hook wire localization was 8.4 min (range: 4 min-18 min). hTe mean procedure time for VATS was 32 min (range: 14 min-98 min). hTe median hospital time was 8 d (range: 5 d-14 d). Results of pathological examination revealed 28 primary lung cancers, 9 atypical adenomatous hyperplasia, and 4 nonspe-ciifc chronic inlfammations. No major complication related to the intraoperative hook wire localization and VATS was noted. Conclusion Intraoperative CT-guided hook wire localization is useful, particularly in small GGO localization in VATS wedge resection and has a signiifcantly low rate of minor complications. Lung GGOs carry a 90% risk of malignancy. Aggressive surgi-cal resection of these GGOs is necessary and feasible through the guidance of intraoperative CT localization technique.

BACKGROUND:Studies have shown that poor dynamic postural control may lead to abnormal movement patterns during exercise,which may increase the risk of lower limb joint and anterior cruciate ligament injury.The stability of the body core is the basis of good dynamic postural control. OBJECTIVE:To investigate the effects of core stability training on dynamic postural control and risk of injury in landing movements,and to compare the differences in training effects between genders. METHODS:Thirty-five college students(male=19,female=16)were recruited for 6 weeks of core stability training.The results of the Y balance test,trunk extensor endurance test,trunk flexor endurance test,lateral bridge endurance test,and landing error scoring system were analyzed before and after training. RESULTS AND CONCLUSION:The 6-week core stability training could improve trunk extensor endurance(P＜0.001),flexor endurance(P＜0.001),and lateral abdominal muscle endurance(P＜0.001).Core stability training could improve forward distance(P=0.026),backward inward distance(P＜0.001),backward outward distance(P=0.005)and comprehensive score(P＜0.001)of Y balance test for male and female college students.Landing error scoring system scores of both male and female college students significantly decreased after 6 weeks of core stability training(P＜0.001)while increasing knee(P＜0.001)and hip flexion angles(P＜0.001),decreasing knee valgus angle(P＜0.001)at the moment of touchdown,and could increase the maximum knee flexion angle(P＜0.001)and decrease the maximum knee valgus angle(P＜0.001).It is concluded that core stability training improves dynamic postural control and improves landing movement patterns,suggesting that it may help reduce the risk of anterior cruciate ligament injury.There are no sex differences in core stability training in terms of increased trunk flexor endurance,lateral bridge muscle group endurance,improved dynamic postural control,and reduced risk of anterior cruciate ligament injury.