Shaping ability of the M4 handpiece and Safety Hedstrom Files in simulated root canals

The aim of this study was to assess the shaping ability of the M4 reciprocating handpiece and Safety Hedstrom files in simulated canals. A total of 40 simulated canals of various angles and positions of curvature were prepared with an M4 handpiece using Safety Hedstrom files oriented with the ground, flattened surface towards the inner aspect of the curve. A standard regimen was adopted throughout. Pre- and post-operative longitudinal images of the canals were taken with a video camera and stored and manipulated in a computer with image analysis software. The presence of canal aberrations and the amount and location of resin material removed as a result of preparation were determined from composite images of superimposed pre- and post-operative views. Preparation time varied significantly (P<0.001) between the canal types; overall, 20° canals were prepared more quickly than 40° canals. Zips and elbows were observed in 16 out of the 40 canals with most (11) being created in 40° specimens. Ledges were found in 19 canals and perforations in only 1. There were no significant differences between canal shapes for these aberrations. Excessive removal of material from the inner aspect of the canal at the curve to create a danger zone was found in 20 canals, but only in those with 40° curves. Significant differences in total canal width between the canal types were seen at the zips (P<0.05), elbows (P<0.05) and danger zones (P<0.001). Transportation at the danger zones varied significantly (P<0.001) between canal types. Under the conditions of this study, the M4 handpiece and Safety Hedstrom files created hour-glass preparations in a substantial proportion of canals. In reality, the Safety Hedstrom file with its one flattened surface was ineffective at reducing removal of material along the inner aspect of canal curves in severely curved specimens and clearly has the potential to create strip perforations in teeth.     

Changing the College AOD Environment for Primary Prevention

Identifying environmental factors reflected to alcohol use is important for program planning and evaluation in college alcohol and drug prevention programs. Little has been written concerning uses of data in environmental prevention efforts. This paper presents four brief interrelated case studies of how environmental modifications were used by a college alcohol prevention project to 1) change the marketing practices and service policies of a student-oriented bar, 2) alter the sales practices of a campus bookstore concerning alcohol paraphernalia, 3) to develop a campaign with the goal of reducing risk factors related to heavy drinking at private student parties, and 4) stop an unsafe bus from transporting students to bars in Mexico. Creative use of such environmental prevention approaches has potential benefit to colleges and universities concerned with the primary prevention of alcohol-related problems experienced by students.     

5-Fu经过ENT还是CNT进入胰腺癌细胞

目的通过测定细胞内5-Fu浓度的变化,判断5-Fu进入细胞的通道。方法细胞培养至2×107后,分为ENT非阻断组和ENT阻断组,前者培养基中仅加入100 ng/L的5-Fu,后者培养基中加入100μmol/L潘生丁和100 ng/L的5-Fu,分别作用15、30、1 h、2 h、4 h后收集细胞,测定细胞中5-Fu含量,并计算单细胞中5-Fu的浓度。结果ENT非阻断组和ENT阻断组细胞内5-Fu的含量,在五个位点上均有较大的差异性(P<0.01)。结论5-Fu既可通过ENT进入细胞,又可通过CNT进入细胞。     

城市生活垃圾收运模式研究——以深圳市为例

介绍了深圳垃圾收运系统,对以垃圾压缩车为主、配套小型垃圾转运站和桶屋的旧模式与以集装箱垃圾运输车为主、配备环保型转运站的新模式的运行费用进行了比较,指出新模式的费用较低,技术优势、规模效应和管理效益显著.     

大鼠周围神经端侧吻合后再生轴突的功能恢复

目的：探讨周围神经端侧吻合后感觉轴突和运动轴突再生的差异以及比较神经端端吻合与端侧吻合的效果。方法：２０只雄性ＳＤ大鼠,随机分为两组,Ａ组为右侧腓神经切断,远侧断端与胫神经行端侧吻合;Ｂ组为右侧腓神经切断,即行端端吻合;两组大鼠左侧留作正常对照。ＨＲＰ染色逆行追踪检测轴突再生神经元。结果：实验侧疹髓前角及脊神经节可见ＨＲＰ标记细胞,端端吻合效果显著好于端侧吻合后再生纤维中感觉纤维和运动纤维兼而有之     

How to improve histopathological results in the biopsy diagnosis of gut dysganglionosis

In a methodological survey, the technical prerequisites for optimal histopathological diagnosis of gut dysganglionosis are presented. To make a proper diagnosis, the pediatric surgeon or gastroenterologist and the pathologist must consider certain preconditions. The most important steps for the optimal biopsy diagnosis of an aganglionosis, an ultrashort Hirschsprung segment, a intestinal neuronal dysganglionosis (IND), a ganglioneuromatosis, a hypogenesis, or immaturity of the vegetative gut innervation are: (1) taking 3–4 biopsies the size of a peppercorn (3–5 mm³) with submucosa; (2) the best instruments for taking rectal mucosal biopsies are forceps and scissors or a conventional large biopsy forceps; and (3) biopsies may be taken 1 cm, 3–4 cm, 6–9 cm, and 9–12 cm (or from a preternatural anus) above the pectinate line. A biopsy containing mucosa, muscularis mucosae, and submucosa guarantees a satisfying histopathological diagnosis. The native biopsies can be transported on water-ice if the distance to the pathologist takes no longer than 4–6 h. For long distances, biopsies have to be frozen on dry ice (CO₂ –80 °C) and transported in a sufficient amount of dry ice (adapted to the time of transportation). For biopsy processing, the following points are important: a total of 122 to 160 15-m-thick native cryostat serial sections have to be cut per biopsy and distributed on four microscope slides. Forty sections are used for lactic dehydrogenase reactions, 32 for succinic dehydrogenase reactions, and the rest for an acetylcholinesterase (AChE) reaction. An AChE reaction alone is sufficient for the diagnosis of Hirschsprung's disease (HD), but never for IND or other developmental malformations of the submucous and myenteric plexuses. Enzymehistotopochemical reactions allow the assessment of functional parameters. These reactions, in contrast to immunohistochemical staining, offer information about the functional activity of special gut structures, e. g., increased AChE activity in nerve fibers of the rectal wall in HD or a lack of dehydrogenase activity in immature ganglia.     

Effect of distance and population size on patient trips in a prefecture of Japan: Application of a transportation distribution model to the demand for and supply of health services

The gravity model, a method for analyzing transportation distribution in transportation engineering, was used to explain patient trips between ten health service regions in a Japanese prefecture. The OD (Origin-Destination) tables were constructed with zoning by regions, distinguishing between out- and inpatients. The observed trips were determined from the data of a survey conducted in 1992 that reported the locations of patient residences and chosen medical facilities. The base values used in the model calculations were the population size of each region and the road distance between the centers of regions. Problems of intrazonal trip were avoided by setting a mean intrazonal movement distance. This model was calibrated by the linear regression method with simultaneous validation by the index of correlation coefficients. The model was found to accurately simulate the effect of distance on the choice of medical facilities and the differences between the characteristics of in- and out-patients. The population value in use showed the relation not only with demand but also the supply of clinical services. It was suggested that the model presented here was useful in the allocation of medical resources and would help explain the relationship between suppliers and consumers of medical services.     

简易标准运血箱的研制与应用

采用发泡聚苯乙烯（EPSⅡ级）及双瓦楞纸箱为材料制作标准运血箱，以湿冰为冷源，经试验测试表明该箱具有良好的隔热保温和抗压抗震功能，适用于平战时大批量的血液运输，是实现战时血液储运标准化、模块化的理想包装容器。     

Analysis of time intervals related to STEMI management in 2008–2016

IntroductionA modern treatment of patients with ST segment elevation myocardial infarction (STEMI) is based on a rapid primary percutaneous coronary intervention with direct recanalization of the affected coronary artery (dPCI). The outcome of the treatment depends largely on the pre-hospital care management, which can reduce the total ischaemic time and subsequently improve patient's outlook.AimsThe principal aims of this retrospective study were to assess the development of time intervals related to the pre-hospital care and the effect of the mode of transportation to the cathlab (primary vs secondary) on these intervals in patients with acute STEMI treated by primary PCI in 2008, 2010, 2012, 2014 and 2016.MethodsWe have analysed patients with STEMI treated using PCI within 12 h of symptoms onset. In total, 1250 patients were included. To evaluate the development over the last 8 years, uni- and multivariate analyses were used. Categorical variables were analysed using chi-squared tests while continuous variables were analysed using one-way ANOVA and general linear models. The effect of the year and of mode of transportation on time intervals were studied.ResultsThe time intervals did not significantly differ among years with the exception of 2014 where the reason of the deviation was however not related to the quality of the pre-hospital care. The 120 min limit from the first medical contact to unblocking the affected artery (FMCTB) was met in more than 80% patients (80.8), the recommended limit of 90 min in 55.2% of patients. The key factor affecting the total ischaemic time was however the patients’ choice of the mode of transportation – in patients who opted for the primary route of transportation, i.e., called the ambulance, the intervals were significantly shorter (FMCTB on average by 38.2 min and total ischaemic time by 92.9 min). The principal delays were detected in the patients’ delay (103 min inpatients with primary transportation route, 131 in patients with secondary route) as well as, unfortunately, in the intervals between reporting the patients’ problem to the system and ECG-confirmed diagnosis (26 min if the patient calls ambulance vs 52 min if they present at a general practitioner or outpatient clinic) and subsequent transportation to the cathlab (60 min for primary route, 97 for secondary). The latter two should be in particular targeted and we can see a significant room for improvement here.ConclusionThe time intervals do not vary among individual years (with some exceptions). The route of transportation, which is a patient's choice, on the total ischaemic time is however a crucial and predominant factor affecting the total ischaemic time as well as individual intervals.