Objective:To investigate the effects of different shapes of implant on stress distribution in implant-bone interface and to select the most appropriate shape for orthodontic anchorage. Method:3-dimesional finite element analysis method was used to analyze the stress and strain in implant-bone interface of knife-edged threaded, square threaded and smooth type implants.Results: The first,second and third main stress (MPa) of knife-edged threaded implant were 6.67, 1.47 and 0.52 respectively with 7.72 MPa of Von Mises stress;those of square threaded 13.00,2.51,0.57 and 11.8;smooth type 10.50,2.50,0.67 and 12.60,respectively. The variables of alveolar bone at the cervix of knife-edged threaded,square threaded and smooth type implants were (0.11×10-3), （0.13×10-3） and （0.94×10-4) mm respectively. Conclusion: The stress in knife-edged threaded implant-bone interface and alveolar bone deformation at the cervix of the implants is minimal,therefore the implants are more suitable for orthodontic anchorage.

Objective:To establish a 3-dimensional finite element model for implant in molar deprived region of mandible. And to lay basis for precise analysis for the biomechanic characteristics of implant anchorage system. Methods:The cross section outline drawn from the molar deprived region of mandible was input into a computer, and ANSYS 5.5 (Swanson Analysis Systems, Inc. Houston, USA) finite element analysis software was used to perform the finite element modeling of the mandible.Results:The cross section outline of the mandible,imitated by a spline curve was smooth and lifelike. This cross section outline was extruded into a three dimensional model. The three dimensional models of the implant and mandible could be smartly meshed to obtain the finite element model of mechanics. Conclusion: An effective 3-dimensional finite element biomechanical analysis model for implant as orthodontic anchorage was established.

Stereotactic body radiotherapy (SBRT) can treat the lesions in asurgical manner and inhibit tumor cell proliferation.Furthermore,it has a character of non-invasive,which shortens the duration of treatment.Although surgery and radiotherapy are the major means for early stage peripheral non-small cell lung cancer,some studies in recent years show that SBRT has certain advantages in local control ratio and adverse reaction compared with radiotherapy,and acquires the similar curative effect with surgery.

BACKGROUND:Many studies reported the relationship of the mechanical properties and water content about bone tissue, which is one of organizations containing the lowest water content on human body. Researches on effect of water on biological tribology behavior of bone tissue have been rarely reported and are the experimental study generally. OBJECTIVE:To explore the influence and the damage mechanism of water on biological tribology behavior of bone tissue, by comparing multiscale numerical model established with the experiment. METHODS:Dehydration of the bone tissue was studied by nanoindentation test and both reciprocating sliding and impact wear tests. A multi-scale finite element model was constructed under a flat-on-ball configuration. RESULTS AND CONCLUSION:The viscoelasticity and the tribological properties of bone tissue significantly decreased as well as the different wear mechanisms under applied loading after drying. The analytical results indicated that there were high stress condition, which incurred the micro-crack initiation and the appearance of peeling and wear, around the Haversian canal, circumferential lamellas and the interstitial tissues. Meso-scale:dehydration weakened the function of absorption and interruption of stress, which facilitated crack extension in pore. Micro-scale:the high stress gradient of structure of canaliculi and lacunae is an important cause of tissue damage.

OBJECTIVE:To improve the writing quality prescriptions of traditional Chinese medicines and to facilitate the standardization of traditional Chinese medicine prescriptions.METHODS:A total of 15 000 prescriptions were sampled in our hospital in 2006 for an analysis of the problems in accordance with the related standards specified in Chinese Pharmacopoeia(CP,2005 edition)and the new "Prescription management method".RESULTS:The problems manifested as nonstandard in drug name and footnotes,or overdosage and so on.CONCLUSION:We should strengthen the management of the traditional Chinese drugs and improve our pharmaceutical care.

Objective To investigate the interactional roles corticosterone and stress played during the PTSD-Like memory impairment.Methods First we established the model of PTSD-like memory using three levels of electric shock:0 mA,0.8 mA and 1.4 mA.The freezing time percent of each group were calculated 24 hours later in order to find which group of rats obtained the PTSD-like memory,and generalizing tests was used to verify it.After the model was established,rats received adrenalectomy (ADX) were operated bilaterally in order to investigate the effect of corticosterone and fed with corticosterone in the drinking water 7 days before fear conditioning.These rats were divided into four groups:control group (no corticosterone supplement,0 mA shock),Cort group (corticosterone supplement,0 mA shock),shock group (no corticosterone supplement,1.4 mA shock),Cort-shock group (corticosterone supplement,1.4 mA shock).A two-way factorial analysis of variance was used to determine whether there was a significant interaction between corticosterone and shock.Results The freezing time percent of group 0.8 mA raised compared with the group 0 mA,whereas the freezing time percent of group 1.4 mA showed reversely and the generalizing effects appeared,compared with group 0.8 mA.In two-way factorial analysis design,the freezing time percent of Cort-shock group significantly increased (P＜0.05) compared with other groups,and there was no significant variance among the other groups.Corticosterone (F=6.464,P＜0.05) and stress (F=53.419,P ＜0.01) played parts in the formation of PTSD-like memory impairment,and they interacted with each other (F=11.580,P＜0.05).Conclusion PTSD-like memory impairment can be induced on rats with high (1.4 mA) electrical shock,and they have interactional effect with each other in the process.

Objective To evaluate the diagnostic value of radionuclide salivagram in children with pulmonary aspiration.Methods From March 2012 to June 2015,a total of 62 patients (37 males,25 females;age range:2 d-14 years) with suspected pediatric aspiration pneumonia were enrolled in this retrospective study.All patients underwent gastroesophageal reflux (GER) imaging and(or) radionuclide salivagram.Detection rate of pulmonary aspiration by the two imaging techniques was compared with x2 test.Results Of 62 patients,14 were diagnosed as pulmonary aspiration,including 1 detected by GER imaging,and 13 detected by salivagram.The detection rate for pulmonary aspiration by radionuclide salivagram (26.0％,13/50) was significantly higher than that by GER imaging (3.1％,1/32;x2=7.211,P＜0.05).Eight of the 13 cases with pulmonary aspiration diagnosed by radionuclide salivagram underwent upper gastrointestinal radiography,and 5 cases had visible contrast agent in the airway.Conclusion Radionuclide salivagram has a higher detection rate for pulmonary aspiration compared to GER imaging,and has good concordance with the traditional upper gastrointestinal radiography.

Background Retina fixed flat-mount perfused by Evans blue (EB) is a common method for the evaluation of blood-retinal barrier (BRB).However,previous method is inconvenient for some laboratories because the retinal specimen can not be observed by gereral microscope rather than confocal laser scanning microscope after the fixation.Objective This study was to modify the preparing way of flat-mounted retina in order to obtain transparent specimen for the observation of rat retinal vessels and the evaluation of leakage under the ordinary fluorescence microscope.Methods Forty male SD rats were divided into the control group,diabetes mellitus (DM) 1-month group,DM 3-month group and DM 6-month group according to the random number table.Streptozotocinum (STZ) of 2％ dissolved in 0.05 mmol/L sodium citrate-hydrochloric acid buffer was intraperitoneally injected in SD rats to establish DM models,and the equal volume of solvent was injected in the same way in the control rats.One month,three months and six months after injection,EB of 30 g/L was injected via rat femoral vein in the dose of 45 mg/kg.Fifteen minutes after injection of EB,the rats were sacrificed and the retinas were isolated and cut radially to prepare the flat-mounted retinas in PBS immediately and then were dried till the specimens were transparent.The specimens were examined under the fluorescence microscope.The percentage of EB leakage was quantitatively calculated by IPP 6.0 software.All procedures were performed following approval of the institutional animal care and use committee of Tianjin Medical University.Results The retina morphology was normal in the control group,and EB filled the vessels,exhibiting the red fluorescence under the fluorescence microscope.Compared with the control group,retinal background fluorescence was enhanced slightly in the DM 1-month group,and focal leakage of the EB from capillaries and focal dilated vessels were found in the DM 3-month group,further,vascular caliber inequality,retinal hypoperfusion area and a larger number of hyperfluorescence areas were seen in the DM 6-month group.The percentage of leakage area was (0.05 ±0.02) ％,(0.27 ±0.06) ％,(1.17 ±0.18)％ and (4.77 ±0.66)％ in the control group,DM 1-month group,DM 3-month group and DM 6-month group,respectively,showing a significant difference among the four groups (F =795.800,P＜0.001),and the leakage area was obviously larger in the DM 3-month group and DM 6-month group than that in thecontrol group (q'=10.338,q'=43.475,both at P＜0.001).Conclusions Modified EB-perfused retinal wholemount method is easy and helpful for clear visualization of retinal vessel leakage induced by BRB breakdown in the diabetic rats under the common fluorescence microscope.

Objective To compare the prescrotal orchiopexy and traditional inguinal orchiopexy in the clinical treatment of children with low cryptorchidism.Methods Seventy-two patients(78 testes)who underwent orchiopexy in our hospital during March 2006 to May 2011 were retrospectively analyzed.And the undescended testis could be manipulated beyond the external inguinal ring under anaesthesia.Matching conditions were age differences among 3 months,same preoperative testicular positioning,same surgeon and same side.Using the paired study of 1 to 1,all the patients were divided into 2 groups: prescrotal orchiopexy(group A)and the traditional inguinal orchiopexy(group B),each group included 36 patients(39testes).Mean age was 5.4 years(group A)and 5.5 years(group B).The time of operation and restore standing,success rate and complications,including hernia,hydrocele,testicular atrophy and ascent were compared between the 2 groups.Results All the patients were successfully operated.The average surgical time for the prescrotal and inguinal groups were 33 and 41 min(P =0.0022),and average time of standing was 1.2 and 5.4 d(P =0.0003).All the patients had no wound infection.Followup ranged from 3 to 65 months.No hernia,hydrocele,testicular atrophy and ascent were identified in either group.The ratios of successful surgery were 100％ in the two groups.Conclusions The prescrotal orchiopexy is simple,safe,and effective in the cases that testis could be pushed down through the external inguinal ring.Compared with traditional inguinal approach,the advantages of prescrotal approach are shorter operative time,fewer traumas,less pain,faster recovery and cosmetic results.

Pyroptosis is a form of new programmed cell death which is dependent on Caspase-1 in recent years.When it' s stimulated by various dangerous signals from hepatic ischemia-reperfusion injury,the intracellular pattern recognition receptors are assembled into inflammasomes and Caspase-1 which was transformed into active form.Activated Caspase-1 promotes the maturation and secretion of pro-inflammatory cytokines IL-1β and IL-18,initiates the innate immunity rapidly and then induces severe inflammatory reaction.In addition,Caspase-1 can also cleave Gasdermin D and release its N-terminal domain triggering pyroptosis.Many studies showed that pyroptosis play a crucial role in hepatic ischemia-reperfusion injury.In this review,we discussed the activation mechanism and research progress of pyroptosis in hepatic ischemia-reperfusion injury.