Objective To develop a mathematical model for clinical calculation of and to verify its practical accuracy in tissue phantom ratios (TPRS). Methods An exponential attenuation algorithm was designed to express the TPRS through a function of any depth and field size of the primary beam with a beam hardening correction coefficient. In our model,the variation of attenuation coefficient with the field size was described by an attenuation factor and the hardening coefficient was replaced by a correction factor. Results From fitting in with the published TPR data of 6, 18 and 24?MV X-rays at the normalization depth sufficient for electron equilibrium, it was found that the attenuation factor can be described by a second-order function of field sizes. And the correction factor exhibited a linear relation to the attenuation factor. In order to determine the five parameters needed to calculate the above attenuation factor and correction factor, only eight TPR values at four extreme and mode rate field sizes were measured. A linear fit to the quality index(QI) showed that these parameters were strongly energy-dependent with R2 ranging from 0.844 to 1.000. The attenuation coefficient and hardening coefficient of the primary beam were calculated directly from two parameters. The derived initial attenuation coefficients from QI fitted well to published experimental data and the hardening coefficients were also consistent with measured data. Compared with practical measured results,the error rate of derived functional TPRS,presented within 1.5% at 6?MV, 1.2% at 18?MV and 1.1% at 24?MV X-ray.The principal attenuation and havdening coefficients were also obtained from our developed model.Conclusions The derived model is able to accurately describe the central axis dose distribution of the primary photon beam and be used to calculate the clinical TPR table from limited TPR values.

Objective The aim of this study is to observe the clinical characteristics and surgical effects of macular hole retinal detachment in high myopia patients with pars plana vitrectomy (PPV)and secondary internal limiting membrane (ILM)peeling.Methods This was a retrospective study.The clinical data of 1 5 patients (1 5 eyes)with macular hole retinal detachment and high myopia,who underwent primary PPV and secondary ILM peeling,were analyzed,including disease history,refraction diopter,ocular axis length,posterior scleral staphyloma,BCVA,macular reattachment and macular hole heeling.There were 3 males (3 eyes)and 12 female (12 eyes),the average age was (60.80 ± 5.85 )years.All patients were examined by best corrected visual acuity (BCVA ), slit lamp microscopy with 90D pre-lens, indirect ophthalmoscopy,A scan and optical coherence tomography (OCT).After the first PPV and silicone oil tamponade,a shallow retinal detachment around the macular hole,especially around the scleral staphyloma was detected by OCT.During the 2nd surgery to remove the silicone oil,ILM peeling and C3 F8 tamponade were performed.Results The average refraction diopter was (- 12.6 ± 1.86)D,the average ocular axial length (29.82±0.993)mm and the average disease duration was (5.20±1.24)months.All eyes had total retinal detachment of all four quadrants,choroid detachment and macular choroidal atrophy,and type ⅡCurtin posterior scleral staphyloma. After the second surgery, all had retina attached by fundus examination.OCT examination indicated that macular hole closure in 7 eye,macular hole attached and retinal attached in 8 eyes.Their BCVA improved after both the first and second surgery (P =0.000),the BCVA after second surgery was better than that after first surgery (P =0.038).Conclusions The clinical characteristic of our series of patients were as follows:long history,with choroidal detachment and type ⅡCurtin posterior scleral staphyloma.All 1 5 eyes showed retinal attached after secondary ILM peeling.The secondary ILM peeling and C3 F8 tamponade may improve the visual outcome and retinal reattachment rate.

After a descrption of the background of patron-driven acquisition ( PDA) or demand-driven acquision (DDA) and its short-term loan model, purchase model, auto-purchase model, librain-purchase model, and evi-dence-based acquisition model, the total amount of resources in common PDA platform, PDA models and their users were analyzed.The key problems in PDA implementation were pointed out, such as formulation of criteria for the development of resources, control of funds, mangement of MARC data, and assessment of PDA project, and sug-gestions were put forward for their solution .

It is the trend to integrate the curriculum contents and strengthen the ability training in reform of edu-cation model at present .After the abilities to develop and maintain medical informatics-related information sys-tems, to process medical information and to provide medical information service were analyzed, certain suggestions were put forward for the practical teaching reform of medical informatics according to the requirements of ability training and the characteristics of subject knowledge structure .

The lung cancer outbreak takes the first place in the global malignant tumor outbreak,becoming mainly reason to make death.Non-small cell lung cancer accounts for 80% of lung cancer around,70%～80% has already belonged to a later period while diagnosing(Ⅲ～Ⅳ period),It is the recommendation mode for later period NSCLC that the chemotherapy and radio treatment to put.The solution of using DDP/CBP with taxanens/gemcitabine/vinorelbine can raise curative effect further.It is a new way to treat later period NSCLC that is to use targeted treatment drug.

Objectives To analyze the influence factors for promoting appropriate health technologies to rural health workers in Zhejiang province. Methods 1957 health workers from county and township levels were surveyed by questionnaires, regarding their use of appropriate technologies. Results The influence factors for rural health workers to employ such technologies include their medical competency, training approach and technical categories. Those medical workers of higher education are

Medicine, Chinese Traditional ; Translations

The languages, types and number of digital resources in 8 domestic medical and pharmaceutical college and university libraries were analyzed , which showed that although certain successes have been achieved in devel-opment of digital resources in these libraries, there are some problems needing to be solved, such as weakness in new digital resources development , insufficient integration of free and open access resources , insufficient organiza-tion and revealing of resources .Suggestions were put forward for the solution of these problems , such as optimizing digital resource structure, developing characteristic digital resources, sufficient organizing and revealing digital re-sources.

0.05),but significantly between VEGF levels before(261?135 pg/ml) and after(679?175 pg/ml) treatment in control group(P

Objective To study whether G3PD modifier protein (MP) could repair tubular epidermal cell(TEC) and ameliorate renal functions in aged rats with gentamycin induced acute tubular necrosis(ATN). Methods Aged and young rats were randomly divided into 3 groups, namely aged and young normal groups, aged and young model groups and the aged and young MP groups. The animal models of acute renal failure (ARF) were induced by gentamycin (140 mg?kg -1 ?d -1 , ip?7 d). Nitric oxide (NO) concentration was determined by Cd activated cadmium reduction method, malonaldehyde(MDA) with thiobarbituric acid test, superoxide dismutase(SOD) with hydroxylamine test, serum creatinine (Scr) with picric acid method, and the renal histology was observed by light and electron microscopy. Results NO was significantly higher in the aged MP group than that in the aged model group 〔serum: (94.29?7.68)?mol/L vs (70.14?5.53)?mol/L, P