With the development of the computer simulation technology and the digital simulation technology, the traditional calculation method has been gradually replaced by the digital method to deal the road traffic accident scene and analyse the process. The PC-Crash software simulation system can reconstruct the traffic accidents within 32 vehicles, and the accuracy of reconstruction has been fully verified, which is widely used by the transport police department and the accreditation agency. In this paper, the research of road traffic accident reconstruction using PC-Crash software is reviewed, and the application of road traffic accident reconstruction technology based on PC-Crash software and some existing problems in forensic practice are discussed, which provides reference for the research and identification of road traffic accident simulation and reconstruction and theoretical basis for accident treatment.
Accidents, Traffic ; Computer Simulation ; Humans ; Models, Theoretical ; Police ; Software

OBJECTIVE: This study aims to assess the effects of the different thicknesses of body-shade resin layers on the color of polyetheretherketone (PEEK)-Crea.lign restorations. METHODS: Five PEEK specimens with the thickness of 0.6 mm were prepared. The color values of PEEK specimens were measured. Afterward, opaque-shade resin layers (0.1 mm) and body-shade resin layers (1.5 mm) were stacked with mold. The five specimens were evenly ground to a thickness of 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.2, and 0.0 mm in sequence. After grinding and ultrasonic cleaning, the color value was measured. RESULTS: With the constant thickness of PEEK and 0.1 mm thickness of opaque-shade resin layer, the L*, a*, and b* values all showed downward trend with the increased thickness of the body-shade resin layer (1.0-1.4 mm). With the constant thickness of PEEK and 0.1 mm thickness of opaque-shade resin layer, the color difference between the adjacent groups was less than 1.5 NBS. This difference between nonadjacent groups was more than 1.5 NBS when the thickness of the body-shade resin layer reached 0.6 mm. Color difference between PEEK-Crea.lign restoration and PEEK was more than 1.5 NBS. CONCLUSIONS The thickness change in the body-shade resin layers influence the color of the PEEK-Crea.lign restorations. Using A2 shade Crea.lign, opaque-shade resin layer thickness is 0.1 and 0.6 mm thickness of body-shade resin layer can produce color which clinically acceptable.
Color ; Composite Resins ; Ketones ; Polyethylene Glycols

OBJECTIVES: To study the effect of hypertensive disorders of pregnancy on peripheral venous blood cell count in preterm infants with a gestational age of 28-34 weeks. METHODS: A total of 227 preterm infants with a gestational age of 28-34 weeks who were admitted to the Department of Pediatrics, the First Hospital Affiliated to Kunming Medical University, from January to December 2020, and whose mothers had hypertensive disorders of pregnancy were enrolled as the study group. A total of 227 preterm infants with a gestational age of 28-34 weeks who were admitted during the same period and whose mothers did not have hypertensive disorders of pregnancy were enrolled as the control group. According to maternal blood pressure during pregnancy, the study group was divided into three subgroups: gestational hypertension (n=75), mild preeclampsia (n=81), and severe preeclampsia (n=71). According to the birth weight of the preterm infants, the study group was divided into two subgroups: small for gestational age (SGA) (n=113) and appropriate for gestational age (AGA) (n=114). Peripheral blood cell count on day 1 after birth was compared between the study and control groups, as well as between the subgroups of the study group. RESULTS: Compared with the control group, the study group had significantly lower white blood cell count, absolute neutrophil count, and blood platelet count (P<0.05) and significantly higher incidence rates of leucopenia and neutropenia (P<0.05). The subgroup analysis showed that the mild preeclampsia and severe preeclampsia subgroups had significantly lower white blood cell count, absolute neutrophil count, and blood platelet count than the gestational hypertension subgroup (P<0.05), and that the SGA subgroup had significantly lower white blood cell count, absolute neutrophil count, and blood platelet count than the AGA subgroup (P<0.05). CONCLUSIONS Hypertensive disorders of pregnancy can affect the peripheral venous blood cell count of preterm infants, which is more significant in infants with maternal preeclampsia and SGA infants.
Child ; Female ; Gestational Age ; Humans ; Hypertension, Pregnancy-Induced ; Infant ; Infant, Newborn ; Infant, Premature ; Infant, Small for Gestational Age ; Platelet Count ; Pregnancy

Integrin is a family of transmembrane heterodimer receptor formed by α and β two subunits, which transduces external signals into cells through reaction with extracellular matrix and is crucial to cell survival, migration, and differentiation. With the deep studies on multipotential differentiation of mesenchymal stem cells (MSCs), researchers found that the differentiation of MSCs depends on integrin related signaling pathways, including MAPK, Wnt and PI3K signaling pathways and so on. However, there are many factors affecting the expression and activation of integrin, such as nano morphology microenvironment, ascorbic acid, bone morphogenetic protein-2, fibronectin, cadherin, fluid shear stress and so on. In this review, we mainly discuss the integrin expression, the promoting effects of integrin on the differentiation of MSCs and their underlying mechanisms.

OBJECTIVE: To explore the relationship between occupational stress response and psychological symptoms of metro-drivers and the mediating role of neurotic personality. METHODS: A total of 396 metro-drivers in a subway operating company were selected as the research subjects using judgment sampling method. Their psychological symptoms, neurotic personality and occupational stress response were evaluated using the Symptom Checklist 90, the Neurotic Subscales of NEO Five-Factor Inventory, and the Personal Strain Questionnaire of Occupational Stress Inventory Revised Edition. RESULTS: The scores of psychological symptoms, neurotic personality and occupational stress response in the metro-drivers were(148.8±42.7),(29.3±6.3) and(104.2±14.2), respectively. The occupational stress of metro-drivers was positively correlated with the psychological symptoms score(correlation coefficient was 0.45, P<0.01), and neurotic personality was positively correlated with occupational stress response and psychological symptoms scores(correlation coefficients were 0.44 and 0.53 respectively, all P<0.01). The occupational stress response of metro-drivers played a direct effect on their psychological symptoms, and the direct effect was 0.825. Neurotic personality played a partial mediating effect between occupational stress response and psychological symptoms, and the mediating effect was 0.537, accounting for 39.4% of the total effect. CONCLUSION: The neurotic personality of metro-drivers plays a partial mediating role between occupational stress response and psychological symptoms.

Objective: In order to understand the current situation and influencing factors of teaching quality in a Medical University in Yunnan, thus improving the teaching quality of the teachers. Methods: The self-made evaluation forms for teachers' teaching quality which include 9 first-level indicators were adopted. In December 2016, a survey was conducted on some students from grade 2013 to 2016 about the teachers who gave them lectures from September to December 2016, involving 7 different majors, 23 teachers and 18 courses. SPSS 21.0 was used for data analysis. Enumeration data were described by frequencies and percentages. Univariate and multivariate Logistic regression analyses were used for satisfaction. Results: There were 1 542 valid questionnaires collected in this survey. Univariate Logistic regression analysis showed that there were 6 factors related to the overall satisfaction of teachers' classroom teaching quality, which were "whether the courses are professional (OR=1.430)", "curriculum difficulty (OR=1.731)", "curriculum progression (OR=1.620)", "learning time after class (OR=1.141)", "interest before class (OR=1.565)", and "interest after class (OR=2.291)", respectively. Conclusion "courses are professional", "courses are too easy", and "the progression of courses is slow " are favorable factors for high satisfaction degree, while "courses are set up by the departments that the students belong", "learning time used after class is too short", and "interest for study is decreased after class" may be unfavorable factors for high satisfaction degree.

OBJECTIVE: To explore the method and curative effect of double bundle reconstruction of posterior cruciate ligament with total internal short tendon technique. METHODS: From October 2010 to June 2018, 50 patients with simple posterior cruciate ligament rupture were admitted, including 35 males and 15 females, ranging in age from 20 to 45 years old, 16 with acute injury and 34 with old injury. The posterior cruciate ligament (PCL) was reconstructed by double bundle technique with the whole internal short tendon. The two ends of the transplanted ligament were fixed by titanium plate suspended with adjustable loop. The Lysholm knee score and IKDC score were used to evaluate the clinical effects. RESULTS: All the 50 patients were followed up, and the duration ranged from 6 to 60 months, with a mean of (28.84±9.52) months. At the latest follow up, the knee joint activity returned to normal range. The median value of Lysholm knee score was 54 before operation and 100 after operation. According to the IKDC score, there were 0 case of grade A, 0 case of grade B, 20 cases of grade C and 30 cases of grade D before operation;29 cases of grade A, 19 cases of grade B, 1 case of grade C and 1 case of grade D after operation;the difference was statistically significant (<0.01). CONCLUSION Arthroscopic double bundle reconstruction of posterior cruciate ligament with short internal tendon is safe and reliable, with less tendon transplantation, more stable fixation, and more bone reserve, which is beneficial for healing and renovation. The short term effect is positive.
Adult ; Anterior Cruciate Ligament Injuries ; Arthroscopy ; Female ; Humans ; Joint Instability ; Knee Joint ; Male ; Middle Aged ; Posterior Cruciate Ligament ; Tendons ; Treatment Outcome ; Young Adult

Objective : To ob serve the expression and trends of tight j unction proteins Occludin and zonula occluden-1 (ZO-1) in blood brain barrier (BBB) of rats with traumatic brain injury (TBI) , and to explore the intervention effect of cannabidiol (CBD) on the BBB . Methods : The TBI model of rat was prepared by modified “Feeney free fall method ”and randomly divided into three groups : the sham operated group ( Sham group) , the model group (TBI + vehicle group) and the CBD intervention group ( TBI + CBD group) , with 24 rats in each group . Each group was subdivided into six time points : 8 h , 1 , 2 , 3 , 5 and 7 d after injury. The expression of Occludin and ZO-1 , which are closely related to the permeability of BBB , was detected by immunohistochemistry , immuno fluorescence staining and Western blot at different points . The permeability of BBB was detected by sodium fluores cein assay. Results : The results of immunohistochemistry showed that compared with Sham group , the positive ex pression of Occludin and ZO-1 decreased with time after brain trauma ( P < 0.05) , and both reached the lowest level at 2 d . The expression levels of Occludin and ZO-1 were up regulated after 1 d of CBD intervention ( P < 0.05) . Immunofluorescence staining showed a similar trend to Western blot results , with Occludin and ZO-1 fluo rescence expression intensity and protein expression reduced after TBI compared with Sham group ( P < 0.05 ) . And the expression levels of Occludin and ZO-1 were up regulated after 2 d of CBD intervention (P < 0.05) . The results of fluorescein sodium experiment showed that the BBB integrity of brain tissue was destroyed after TBI , and the permeability increased after TBI (P < 0.01) . The permeability of BBB decreased after CBD intervention (P < 0.05) . Conclusion The expression of tight junction proteins O ccludin and ZO-1 decreases after TBI , and the permeability of BBB is disrupted , and CBD intervention reverses the disruption of the BBB by TBI .

OBJECTIVETo find a simpler, effectiver with less side-effect method for treatment of ectopic pregnancy.

METHODSOne hundred and fourteen patients of ectopic pregnancy were divided into two groups, the 56 patients in Group A were treated with Mifepristone and Chinese herbal medicine (CHM), and 58 patients in Group B were treated with Methotrexate and CHM. The therapeutic effect in both groups was observed and compared.

RESULTSThe rate of success in Group A was 82.14% and in Group B 70.69%, comparison between them showed no significance (P > 0.05). Time for successful treatment was 14.54 +/- 5.87 days in Group A and 9.00 +/- 5.09 days in Group B, comparison of them showed significant difference (P < 0.01). Insignificance revealed in comparison between the occurrence of side-effects for the groups, such as nausea, vomiting, diarrhea, liver dysfunction and lowering of white blood cells, but significance was shown in re-menstruation time (43.43 +/- 1.77 days vs 38.38 +/- 1.13 days, P < 0.05).

CONCLUSIONTreatments of combined CHM with Mifepristone or Methotrexate showed similar therapeutic effect in treating ectopic pregnancy, but the latter showed a quicker initiation and less side-effects in delaying the re-menstruation time.

Abortifacient Agents ; therapeutic use ; Adult ; Drug Therapy, Combination ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Humans ; Methotrexate ; therapeutic use ; Mifepristone ; therapeutic use ; Phytotherapy ; Pregnancy ; Pregnancy, Ectopic ; drug therapy

OBJECTIVETo assess the feasibility of performing enhanced pulmonary vein computed tomography (CT) with low radiation dose using tube voltage of 100 kV combined with current automatic regulation technology.

METHODSPatients were divided into 100 kV group (n=26) and 120 kV group (n=43) based on the tube voltages, and their pulmonary veins were scanned with current automatic regulation technology. The image qualities of these two groups were compared using quantitative and qualitative approaches.

RESULTSThe effective dose in 100 kV group was 24% lower than that in 120 kV group (p<0.01) . The image quality was similar between these two groups (p>0.05) : the contrast to noise ratio was not significantly different (p>0.05) ; for the scores of image quality estimated by the eye, they were 5 in 13 cases, 4 in 11 cases, and 3 in 2 cases in 100 kV group and 5 in 31 cases, 4 in 8 cases, and 3 in 4 cases in 120 kV group (p>0.05) .

CONCLUSIONThe enhanced pulmonary vein CT with tube voltage of 100 kV and 120 kV combined with current automatic regulation technology can reduce the radiation dose without sacrificing the image quality.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Coronary Angiography ; methods ; Feasibility Studies ; Female ; Humans ; Male ; Middle Aged ; Phantoms, Imaging ; Pulmonary Veins ; diagnostic imaging ; Radiation Dosage ; Signal-To-Noise Ratio ; Tomography, X-Ray Computed ; methods ; Young Adult