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691.
Pathak S.D. Grimm P.D. Chalana V. Yongmin Kim 《IEEE transactions on medical imaging》1998,17(5):762-771
New biopsy techniques, increased life expectancy, and prostate-specific antigen (PSA) screening have contributed to an increase in the reported incidence of prostate cancer. Among several treatment options available to the patients, transperineal prostate brachytherapy has emerged as a medically successful, cost-effective outpatient procedure for treating localized prostate cancer. Transperineal prostate brachytherapy employs transrectal ultrasound (TRUS) as the primary imaging modality to accurately preplan and subsequently execute the placement of radioactive seeds into the prostate. Under TRUS guidance, a needle (preloaded with radioactive seeds) is inserted through a template guide, through the perineum and into a predetermined prostate target. The pubic arch, formed by the central union of pelvic bones, is a potential barrier to the passage of these needles in the prostate. A critical aspect, therefore, in the planning and execution of the brachytherapy procedure is the accurate assessment of pubic arch interference (PAI) in relation to the prostate. Traditionally, the evaluation of PAI has involved computed tomography correlate scanning or crude subjective evaluations. In this paper, the authors describe a new method of assessing PAI by detecting the pubic arch via image processing on the TRUS images. The PAI detection (PAID) algorithm first uses a technique known as sticks to selectively enhance the contrast of linear features in ultrasound images. Next, the enhanced image is thresholded via percentile thresholding. Finally, the authors fit a parabola (a model for the pubic arch) recursively to the thresholded image. Their evaluation result from 15 cases indicates that the algorithm can successfully detect the pubic arch with 90% accuracy. Based on this study, the authors believe that detecting the pubic arch and assessing PAI can be done practically and more accurately in the clinical setting using TRUS rather than the current available methods 相似文献
692.
S Pathak MA Nemeth AS Multani GN Thalmann AC von Eschenbach LW Chung 《Canadian Metallurgical Quarterly》1997,76(9):1134-1138
A human prostate tumour cell line, LNCaP C4-2, when injected into athymic male nude mice, produced tumours containing: (1) only human cancer cells similar to those injected; (2) only murine stromal cells containing abnormal chromosome constitutions; or (3) both human prostate cancer cells similar to those injected and the transformed murine stromal cells with altered chromosome constitutions. Karyotypic analysis of murine metaphases from all the host-derived tumours showed mostly pseudodiploid chromosome constitutions, with multiple copies (amplification) of mouse chromosome 15 and the absence of a typical Y chromosome. Fluorescence in situ hybridization analysis of these murine cells, using a biotin-labelled total human DNA painting probe, further demonstrated the absence of human DNA and the presence of only mouse metaphase and interphase cells in these transformed stromal cells. These results suggest that cancer cells are capable of inducing neoplastic transformation in stromal cells of the host organ by some, as yet unknown, epigenetic mechanism(s). 相似文献
693.
Mining affects physical and chemical changes in the mine environment resulting in water pollution. Based on the geological distribution the coal mines in the state of Madhya Pradesh, the Coalfield can be categorised into three basins Northern, Southern and Satpura. The Northern belt lies along the Sone Valley whilst the Southern one lies within mahanadi Valley and the Satpura basin lies south of the alluvial tract. Mine water pollution study reported in this paper is concerned with Chapha Incline, Umaria Coalfield in Eastern Madhya Pradesh. The water analysis was carried out on representative samples obtained from the site on pre- Monsoon and post- monsoon seasons, and reference samples were obtained from the area in the vicinity of the site of investigation. The samples were analysed in the laboratory for determining water quality parameters including trace element detections and microbial analyses. The chemical analysis results of mine water are presented in the form of Durov diagrams. 相似文献
694.
A relatively simple approach is described for developing the complete eigenfunction expansion of time-harmonic electric (bar{E} ) and magnetic (bar{H} ) fields within exterior or interior regions containing an arbitrarily oriented electric current point source. In particular, these results yield directly the complete eigenfunction expansion of the electric and magnetic dyadic Green's functionsbarbar{G}_{e} andbarbar{G}_{m} that are associated withbar{E} andbar{H} , respectively. This expansion ofbarbar{G}_{e} andbarbar{G}_{m} contains only the solenoidal type eigenfunctions. In addition, the expansion ofbarbar{G}_{e} also contains an explicit dyadic delta function term which is required for making that expansion complete at the source point. The explicit dyadic delta function term inbarbar{G}_{e} is found readily from a simple condition governing the behavior of the eigenfunction expansion at the source point, provided one views that condition in the light of distribution theory. These general expressions for the eigenfunction expansion ofbarbar{G}_{e} andbarbar{G}_{m} reduce properly to those obtained previously for special geometries by Tai. 相似文献
695.
Members of the nonreceptor tyrosine kinase family appear to be targeted to caveolae membrane. We have used a Rat-1 cell expressing a temperature sensitive pp60(v-src) kinase to assess the initial changes that take place in caveolae after kinase activation. Within 24-48 h after cells were shifted to the permissive temperature, a set of caveolae-specific proteins became phosphorylated on tyrosine. During this period there was a decline in the caveolae marker protein, caveolin-1, a loss of invaginated caveolae, and a 70% decline in the sphingomyelin content of the cell. One of the phosphorylated proteins was caveolin-1 but it was associated in coimmunoprecipitation assays with both a 30 kDa and a 27 kDa tyrosine-phosphorylated protein. Finally, the cells changed from having a typical fibroblast morphology to a rounded shape lacking polarity. In light of the recent evidence that diverse signaling events originate from caveolae, pp60(v-src) kinase appears to cause global changes to this membrane domain that might directly contribute to the transformed phenotype. 相似文献
696.
An Al-4·5Cu-10Pb alloy was processed by spray forming as well as impeller mixing followed by chill casting methods. The microstructure,
mechanical properties and dry sliding wear characteristics of the alloy were evaluated. The spray formed alloy showed an equiaxed
grain morphology with a uniform dispersion of lead particles in the matrix phase. In contrast a cellular-dendritic morphology
of the primary phase was the characteristic feature of the alloy processed by impeller mixing and chill casting method. The
spray formed alloy indicated its superior mechanical properties and low wear rate particularly at higher applied load and
sliding velocity. The possible reason for this behaviour is discussed in the light of microstructure of the alloy and the
nature of the worn out surfaces of the wear test specimens. 相似文献
697.
Chatterji S. Ranjan K. Bhardwaj A. Namrata Srivastava A.K. Kumar A. Jha M.K. Shivpuri R.K. Khanna S.L. 《IEEE transactions on nuclear science》2004,51(2):298-312
The performance of metal-overhang (MO) equipped silicon micro-strip sensors, after irradiation for the preshower detector to be used in compact muon solenoid (CMS)experiment at the large hadron collider (LHC), CERN, has been studied through simulations. Detailed calculations using Hamburg model have allowed the parameterization of these effects and helped to simulate the operation scenario of MO equipped sensors over ten years of LHC operation. The utility of overhanging metal extension as junction termination technique after space charge sign inversion (SCSI) has been explored in detail for the first time in this work. Several interesting results like a shift in the optimal oxide thickness in MO equipped structures after irradiation have been reported. The comparison of dielectric and semi-insulator passivated MO equipped structures after irradiation has been studied. Also, the impact of various crucial geometrical parameters like device depth (W/sub N/), width of back N/sup +/ layer used for ohmic contact (W/sub N//sup +/), strip width (W), strip pitch (P) and width of overhang extension (W/sub MO/) on the MO equipped structure after SCSI has been presented in detail. 相似文献
698.
SR Gaval SN Shrikhande SK Makhija NS Tankhiwale AA Pathak AM Saoji 《Canadian Metallurgical Quarterly》1996,50(12):335-338
A total of 62 suspected patients of plague were investigated for evidence of Yersinia pestis, by blood culture, lymph node aspirate culture, sputum culture, animal inoculation and serology for f1 antibodies against f1 antigen of Yersinia pestis. None of the samples was positive by direct smear examination and culture for Yersinia pestis, as well as for serology. The non positivity of the cultures is discussed. 相似文献
699.
Some studies on the impact behavior of banded microalloyed steel 总被引:10,自引:0,他引:10
Microalloyed steels are used in automobile industries, offshore platforms and in structural applications. It is essential to establish a relation between service consition such as temperature, loading rate and fracture behavior of the steel. Impact study on new material is very handy to understand the mechanicl properties in a rapid and inexpensive way. The present investigation aims to assess impact toughness (CVN), ductile brittle transition temperature (DBTT, 25J), and initiation dynamic fracture toughness (Jld*) of the indigenously developed microallayed seel. The steel has shown banding with alternate layers of ferrite and pearlite. The banding concentration (ferrite bands per mm) has been altered by heat treatment. Presence of banding has given spikes and splits in impact fracture. Change in banding concentration has affected DBTT of the steel, upper shelf energy and the extent of splitting. A model of crack divider with respect to the present microstructure has been analyzed. Banding in divider orientation improves the impact as well as initiation dynamic fracture toughness of the steel. The effect of temperature on splitting is also discussed. Splits in fractured surface disappear with decreasing temperature and higher numbers of splits yield lower toughness. Further, initiation dynamic fracture toughness is calculated for all temperatures and correlated with impact toughness. 相似文献
700.
A computer method is presented for the analysis of moderately thick flanged shells of revolution such as are used for reactor pressure vessels. The shell may be subjected to symmetrical or unsymmetrical loads and a thermal environment. The method employs a finite element discretization for modelling the flange portions, and a theory appropriate to moderately thick shells for the remainder of the pressure vessel. The governing differential equations for the shell portions are put in the Goldberg-Bogdanoff first-order form and integrated numerically using a scheme such as a Runge-Kutta process. The finite element stiffness matrix for a flange region is used to form a superelement influence coefficient matrix, permitting the flange region to be treated as a giant step in the numerical integration process. 相似文献