This paper analyses the significance of applying investigating study to teaching practice of medical physics at present.It introduces the establishment of a research project of investigating study in medical physics and specific research methods.

Digital X-ray photography has been applied to clinical medicine in recent 3years.This paper introduces the development situation of the flat detectors for digital X-ray photography.The technical indexes and structure differences of the detectors are presented in this paper.

Objective To discuss effective nursing measures for patients with congenital hypospadia with the application of urethral stent.Methods 142 patients with congenital hypospadia were selected and used soft stent during and after operation.The urethral orifice was kept smooth after operation and the stent was removed until 2 weeks after operation.Results Two patients complicated with urethral fistula,one was because of the poor blood supply of the skin flap and the other because of the edema of the skin flap and the remove of stent.Other patients received good treatment effect. Conclusion Application of urethral stent in patients with congenital hypospadia could reduce the incidence of infection and increase the success rate of operation.

Objective To observe the biomechanics of the anterior and posterior interosseous talo-calcaneal ligaments (ITCLs) . Methods Load-displacement characteristics of the subtalar joint were studied in 12 cadaver specimens whose ankle joints were mutilated. The ankle articular surfaces of the talus and the post-calcaneus were exposed. Bone blocks were then embedded in polymethylmethacrylate. The an-terior ITCLs were abscised in 6 of them, and the posterior ITCLs in the other 6. A multi-functional biome-chanical machine was used to perform the biomechanical tests on the specimens. Results When the anterior ITCLs were cut, the tali moved to the anterior-lateral side. When the posterior ITCLs were cut, the tali mostly moved to the anterior-interior side. Conclusions The anterior and posterior ITCLs have dif-ferent roles in maintaining stability of the subtalar joint. Since the posterior ITCLs seem more important than the anterior ones, they should have priority in ITCL reconstruction.

The paper is aimed to study the enzymatic hydrolysis of the activatable cell-penetrating peptide (ACPP) that was designed and synthesized. The ACPP was composed of three parts, polyanionic sequence peptide, peptide sequence that specifically cleaved by matrix metalloproteinase (MMP) and cell penetrating peptide (CPP). The ACPP was hydrolyzed by type IV collagenase (MMP-2/9) under the condition of 37 degrees C and was monitored by reversed-phase high performance liquid chromatography (RP-HPLC). The efflux of peak was collected and detected by matrix assisted laser desorption ionization orthogonal time of flight mass spectrometry (MALDIO-TOF-MS) to speculate the sequences of the peptide fragments. The results indicated that the ACPP could be cleaved by type IV collagenase at target site as predicted, released CPP. The half life of the cleavage was about 4 h. Meanwhile, the peptide fragments may be cleaved again at other sites by type IV collagenase.

Oncogenesis is a sophisticated process which is polygenic , multi-stage,and multi-step.Livin as an apoptosis inhibi-ting factor , is one of the members of apoptosis inhibiting factor family , it expresses highly in many tumor tissues , and is closely related to the occurrence and development of urological tumor .Tumor growth can be inhibited by interfering the expression of Livin in tumor tis-sue,which will reduce the resistance to apoptosis and increase the rate of cell apoptosis .In recent years , more and more attention was paid to the studies of Livin on gene targeting therapy .Further research of Livin might provide new ideas for the early diagnosis , clinical treatment and evaluation of prognosis of tumor .

Objective To evaluate the effect of sevoflurane preconditioning on autophagy during ischemiareperfusion (I/R) injury to isolated rat hearts and the role of PI3K/Akt signaling pathway.Methods Healthy adult male Wistar rats,aged 6-8 weeks,weighing 250-280 g,were anesthetized.Their hearts were excised and perfused in a Langendorff apparatus.Eighty-four isolated rat hearts with I/R injury were randomly divided into 7 groups (n =12 each):normal control group (NC group),I/R group,sevoflurane preconditioning group (S + I/R group),normal control plus wortmannin group (NC + W group),I/R plus wortmannin group (I/R + W group),sevoflurane preconditioning plus wortmannin group (S + I/R + W group),and solvent group (S + I/R + D group).In NC group,the hearts were continuously perfused with K-H solution for 180 min.In I/R group,the hearts were perfused with K-H solution for 30 min,and then subjected to ischemia for 30 min followed by 120 min of reperfusion.In S+ I/R group,the hearts were perfused with K-H solution for 10 min,and then with K-H solution saturated with 2.5％ sevoflurane for 15 min,followed by 5 min washout with K-H solution before ischemia.In NC + W group,wortmannin (PI3K inhibitor) 15 μg/kg was injected intraperitoneally at 30 min before chest opening,and the other procedures were similar to those previously described in group NC.In I/R + W group,wortmarnin 15 μg/kg was injected intraperitoneally at 30 min before chest opening,and the other procedures were similar to those previously described in group I/R.In S + I/R + W group,wortmannin 15 μg/kg was injected intraperitoneally at 30 min before chest opening,and the other procedures were similar to those previously described in S + I/R group.In S + I/R + D group,dimethyl sulfoxide 1.5 ml/kg was injected intraperitoneally at 30 min before chest opening,and the other procedures were similar to those previously described in group S + I/R.The HR,± dp/dtmax,left ventricular developed pressure (LVDP) and left ventricular end-diastolic pressure (LVEDP) were recorded at the end of equilibration and reperfusion.At the end of reperfusion,coronary effluent was collected to detect lactate dehydrogenase (LDH) activity,and myocardial specimens were obtained to calculate the percentage of myocardial infract size.The expression of autophagy marker LC3-Ⅱ and Akt,phosphor-Akt (p-Akt),mammalian target of rapamycin (mTOR),and phosphor-mTOR (p-mTOR) was determined by Western blot.Results Compared with NC group,no significant change was found in the parameters of hemodynamics in NC + W group,and HR,± dp/dtmax and LVDP were significantly decreased,LVEDP,myocardial infract size,and LDH activity were increased,LC3-Ⅱ expression was up-regulated,and the expression of p-Akt and p-mTOR was down-regulated in the other groups.Compared with group I/R,HR,± dp/dtmax,and LVDP were significantly increased,LVEDP,myocardial infract size,and LDH activity were decreased,LC3-Ⅱ expression was downregulated,and the expression of p-Akt and p-mTOR was up-regulated in S + I/R and S + I/R + D groups,and no significant change was found in each parameter in S+ I/R+ W group.Compared with S + I/R group,HR,± dp/ dtmax and LVDP were significantly decreased,LVEDP,myocardial infract size and LDH activity were increased,LC3-Ⅱ expression was up-regulated,and the expression of p-Akt and p-mTOR was down-regulated in S + I/R + W group,and no significant change was found in each parameter in S + I/R + D group.Conclusion Sevoflurane preconditioning can decrease autophagy of myocardial cells during I/R through activating PI3K/Akt signaling pathway and enhancing mTOR activity in the downstream,thus protecting isolated rat hearts against I/R injury.

Many studies have proved that the subchondral bone plays an important role in the development of osteoarthritis,and may be the initial factor of the disease,but the exact relationship between articular cartilage degeneration and subchondral bone sclerosis is still unclear.Subchondral bone sclerosis caused by bone remodeling abnormality severely decreases the ability of subchondral bone stress absorption and protective function of articular cartilage,which finally leads to cartilage degeneration and osteoarthritis deterioration.Studying the role of subchondral bone in the pathogenesis of osteoarthritis and developing potential drugs to regulate subchondral bone remodeling will provide a new way of prevention and treatment for osteoarthritis.

Four 14 to 19, year old boys are used as subjects in this study. The first part of this study attempts to investigate the vitamin C status of these subjects when they are consuming the ordinary diet served in the college staff dining room. The vitamin C content of the whole meal is determined by the dye titration method for ten days. During the first 2 days, blood samples are taken from finger tips and the plasma analyed for vitamin C by the Farmer and Abt method. 24-hour urine samples are also collected and the vitamin C content determined.After the first 3 days, in addition to the vitamin C in the diet, the subjects are subjected to vitamin C saturation by taking orally 400 mg of vitamin C form orange juice for two days followed by 5 days of 100 mg supplementation of crystalline vitamin C. Plasma vitamin C and 24-hour urinary vitamin C are ag(?) studied. Following this procedure, the subjects are considered ready for experimentation. They are put on an experimental diet similar to their ordinary d(?) but devoid of vitamin C. The vitamin C intake level is controlled. Three lev(?) are tried: 70 mg, 50 mg, and 30 mg daily. Each level is fed for 14 days. The vitamin C of the first seven days is provided by vegetables frequently used (?) Canton and crystalline vitamin C is used during the latter 7 days for comparison. Cantonese cabbage(Brassica chinensis L.), Kan Lan Tsai(Brassica alboclabia, R.) and Chinese celery cabbage(Brassica pekinensis, R.)are used for supplying vitamin C during the 70, 50 and 30 mg levels respectively. Plasma vitamin C and 24-hour urinary excretion are determined for the last 5 days of each period.The vitamin C content of the medical college diet averages 43.7 mg per day for the 10 days analyzed. Plasma vitamin C of the subjects ranges from 0.25 to 0.61 mg percent, averaging 0.37 mg percent. 24-hour urinary excretion varies between 3.3 and 74.8 mg daily.During saturation, plasma vitamin C of one subject increases after the first dose, while its content in the plasma of the other three subjects also shows gradual rise. Urinary excretions show immediate and considerable increases on the first day with each of the subjects.During the 70 mg vitamin C daily intake level, plasma vitamin C average 0.45 mg percent and 0.48 mg percent for Brassica chinensis, L. and for crystalline vitamin C respectively. Daily urinary excretions average 19.4 and 18.4 mg. for the two periods. When the vitamin C intake is reduced to 50 mg daily, an average of 0.40 mg percent of plasma ascorbic acid is found for Brassica alboclabia, L. and 0.32 mg percent for crystalline vitamin C. Urinary excretion decreases to 15.2 and 11.9 mg daily. At the 30 mg daily intake level, plasma vitamin C falls to 0.32 mg percent for Chinese celery cabbage and 0.31 mg percent for crystalline vitamin C. Total urinary vitamin C falls to 9.9 and 9.0 mg.The vitamin C from these 3 vegetables are at least as efficiently utilized as crystalline vitamin C.While it is not quite possible to draw definite conclusions in regard to vitamin C requirement of these subjects from the results of this study, there are suggestions however that a daily intake of about 50 mg of vitamin C may be able to maintain a fairly satisfactory state of vitamin C nutrition.

Medical assistance systems are an integral part of the health security system and they represent the integrity and adequacy of health risk protection. The overwhelming majority of developed countries have already es-tablished medical assistance systems to improve the accessibility of healthcare services and provide catastrophic pro-tection for families, especially for the poor. The paper conducts a comparative study of typical foreign medical assis-tance systems, where in the general method by which developed countries embed catastrophe protection mechanisms into public healthcare security systems and provide tilt protection to the needy is described. Medical assistance is pro-vided on a means-test basis and the development of private health insurance is encouraged to alleviate pressure on the public side. Corresponding implications for China are also warranted, including the provision of tilt protection to the needy, to re-define objects and standards of medical assistance, and enhance the coordination of different medical se-curity systems.