Update on the use of percutaneous nephrostomy/balloon dilation for the treatment of renal transplant leak/obstruction

PURPOSE: Retrospective evaluation of the efficacy of percutaneous nephrostomy and nephroureteral stent placement for treatment of post-transplant ureteral leak, and percutaneous nephrostomy and balloon dilation for treatment of post-transplant ureteral obstruction. PATIENTS AND METHODS: Data were reviewed for all patients who underwent percutaneous therapy for complications after renal transplantation between January 1985 and June 1995. A total of 61 patients with complications (leak, n = 17; obstruction, n = 44) had been treated. Patients underwent percutaneous nephrostomy followed by antegrade placement of a nephroureteral stent. In addition, all patients with obstruction also underwent ureteral balloon dilation. Follow-up ranged from 9 weeks to 24 months. Positive outcome was defined as nonsurgical closure of leak, significant improvement in renal function, and removal of the nephroureteral stent with maintenance of stable renal function. RESULTS: Regarding ureteral leak, 10 of 17 patients (59%) healed after treatment. Seven patients (41%) did not respond and went on to surgical repair. All patients with early (n = 13) ureteral obstruction (< 3 months after transplantation), had improved renal function (P < .025). Sixty-two percent of patients with early obstruction were cured (tube out with stable renal function) and 38% went to surgery for ureteral repair. In patients with late (n = 31) obstruction (> 3 months after transplantation), renal function improved in only 58% (P < .01). Only 16% of patients with late obstruction were cured (tube out with stable renal function). Ureteral obstruction was persistent in the remaining patients and did not respond to multiple balloon dilations. All complications were minor and included 23 of 61 (38%) patients with urinary tract infections and nine of 61 (14%) patients with limited hematuria. CONCLUSION: Percutaneous nephrostomy is very effective in improving renal function in patients with early obstruction. It is moderately successful in treating ureteral leak. Ureteral balloon dilatation is moderately effective for treatment of obstruction in the early (< 3 months) postoperative period. However, balloon dilation is minimally successful in curing ureteric obstruction occurring more than 3 months after transplantation.     

Electrospun MgO/Nylon 6 Hybrid Nanofibers for Protective Clothing

Nano-Micro Letters - Magnesia (MgO) nanoparticles were produced from magnesite ore (MgCO3) using ball mill. The crystalline size, morphology and specific SSA were characterized by X-ray diffraction...     

An indexed atlas of digital mammograms for computer-aided diagnosis of breast cancer

Computer-aided diagnosis (cad) systems are being developed to assist radiologists in the interpretation of ambiguous mammographic features corresponding to possible signs of early breast cancer. Databases of digital mammograms are needed for testing such systems; we present an overview of a few such databases. Most databases are limited to single-exam sets of two or four mammograms on which the diagnosis was made, some ground-truth information related to the position of diagnostically significant mammographic features, and the diagnosis. We propose the design of a comprehensive, indexed atlas of digital mammograms. The design of an appropriate indexing scheme facilitates the implementation of content-based retrieval techniques needed for efficient access to and retrieval of relevant cases from the atlas. We also propose the use of mobile software agents for facilitating remote consultation of the atlas. Mobile agents can move between data sources such as the atlas and hospital repositories, perform computational tasks at each site, and return only relevant data to the user. These features reduce the computational requirements of the local computer system, bandwidth requirements, and overall network traffic. Proposed applications of the atlas include research, remote consultation, teaching, evaluation ofcad systems, and self-evaluation by radiologists.     

In the shadow of the boss's boss: Effects of supervisors' upward exchange relationships on employees.

Dyadic relationships in an organizational hierarchy are often nested within one another. For instance, the relationship between a supervisor and an employee is nested within the relationship between that supervisor and his or her boss. In that context, the authors propose that the supervisor's relationship with his or her boss (leader-leader exchange) moderates the effects of the supervisor's relationship with the employee (leader-member exchange). Specifically, the authors argue that leader-member exchange has a stronger positive effect on employees' attitudes toward the organization and its customers when leader-leader exchange is higher. Cross-level analysis of data from 581 frontline nurses and 29 supervisors in a midwestern hospital supports this contention. Implications for research and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative and Qualitative Evaluation of Geometric Deconvolution of Distortion in Limited-View Computed Tomography

Images reconstructed using a set of a few projections spanning a narrow angular range suffer from a systematic geometric distortion due to the point spread function of the reconstruction process. This distortion can be removed by deconvolving a complementary set of projections calculated from the initial reconstruction. Homomorphic deconvolution and inverse filtering techniques were used for this purpose. A second reconstruction is computed from the union of both sets of projections. Although the distortion is removed, the results are noisy due to problems associated with inverse filtering. Two-dimensional (2-D) filtering of the second reconstruction is performed to reduce the noise, while preserving the reduction in geometric distortion. Results obtained using several 2-D filters were compared visually and by point noise content, distortion, and projection error measures. Quantitative measures of geometric distortion removal for test images are also described.     

A new type of Ti-LiNbO3 integrated optical Y branch

A report on the experimental verification of the basic operation of the proposed type of integrated optical Y branch using Ti-diffused lithium niobate is presented. The advantages of this Y branch include low-branching loss, compact size, no need for extra bending or curved elements when used as a 3-dB coupler in M-Z type switches, and freedom from critical fabrication requirements. A branching loss of 0.5 dB is achieved. The necessary three-dimensional analysis of the Ti-diffused Y-branch structure is described     

A modified rule-of-mixtures for prediction of tensile strengths of unidirectional fibre-reinforced composite materials

Measured ultimate tensile strengths in unidirectional fibre-reinforced composite materials have been observed to deviate from the linear predictions of the classical rule-of-mixtures relationship. The physical factors responsible are fibre-fibre interaction, inhomogeneous fibre distribution in the matrix and fibre misorientation to the loading direction. A recent modification to the classic rule-of-mixtures to account for fibre-fibre interaction has already resulted in good agreement between measured and predicted values of ultimate tensile strengths at high fibre volume fractions for Kevlar/epoxy composites. Additional modifications to the rule of mixtures to incorporate both fibre misorientation and inhomogeneous spread have been presented here. These modifications result in greater agreement between measured and predicted ultimate tensile strengths at low fibre volume fractions while retaining the accuracy of prediction at higher fibre volume fractions. Good agreement between measured and predicted values of inhomogeneous fibre spread were obtained at high fibre volume fractions. Furthermore, these additions to the classic rule-of-mixtures can be used to gauge the extent of each of the physical factors responsible for ultimate tensile strength reduction in unidirectional composite materials.     

Effect of nonstoichiometry on mechanical properties of reactive hot‐pressed monolithic ZrCx Ceramic

The reactive hot pressing (RHP) of Zr:C powder mixture at various molar ratios (1:0.5, 1:0.6, and 1:0.67) at applied pressures of 4‐7 MPa and 1200°C resulted in dense ZrC_x ceramics. Nano‐hardness values of ZrC_x are reported to be 21‐31 GPa as “x” was varied from 0.5 to 1.0. However, indentation modulus for all ZrC_x compositions remained at ~350 GPa. Microhardness of the ZrC_x increased from 13 to 15 GPa as the stoichiometry was increased from 0.5 to 1.0. The indentation fracture toughness for ZrC_0.5 was 4 MPa m^1/2, and for ZrC_0.67 it was reduced to 3.6 MPa m^1/2. The 3‐point flexural strength for ZrC_0.5 was determined to be 386 ± 26 MPa, which decreased to 316 ± 20 MPa as the carbon content (ZrC_0.67) was increased. The dry sliding wear of ZrC_0.5 to ZrC_0.6 indicated that the coefficient of friction was increased from 0.73 to 0.86 at 5 N load and 500 m sliding distance. Further, ZrC_0.67 showed a reduction in friction coefficient of 0.81, and this was due to the increase of strong Zr–C covalent bond and unreacted graphite.     

Low-Temperature Processing of ZrB2-ZrC Composites by Reactive Hot Pressing

Dense ZrB₂-ZrC and ZrB₂-ZrC _x∼0.67 composites have been produced by reactive hot pressing (RHP) of stoichiometric and nonstoichiometric mixtures of Zr and B₄C powders at 40 MPa and temperatures up to 1600 °C for 30 minutes. The role of Ni addition on reaction kinetics and densification of the composites has been studied. Composites of ∼97 pct relative density (RD) have been produced with the stoichiometric mixture at 1600 °C, while the composite with ∼99 pct RD has been obtained with excess Zr at 1200 °C, suggesting the formation of carbon deficient ZrC _x that significantly aids densification by plastic flow and vacancy diffusion mechanism. Stoichiometric and nonstoichiometric composites have a hardness of ∼20 GPa. The grain sizes of ZrB₂ and ZrC _x∼0.67 are ∼0.6 and 0.4 μm, respectively, which are finer than those reported in the literature. This article is based on a presentation given in the symposium entitled “Materials Behavior: Far from Equilibrium” as part of the Golden Jubilee Celebration of Bhabha Atomic Research Centre, which occurred during December 15–16, 2006 in Mumbai, India.     

Two-dimensional mullite nanostructure: Synthesis and reinforcement effect on polypropylene/maleic anhydride graft ethylene vinyl acetate matrix

In the present work, we studied the reinforcement effect of mullite nanosheets (MNs) on the properties of polypropylene (PP)/maleic anhydride graft ethylene-vinyl acetate (EVA-g-MA) blend matrix. MNs have been prepared in the presence of polyvinylpyrrolidone (PVP) as the macromolecular surfactant through the sol–gel process followed by a thermal annealing method. The sheet-like morphology of mullite was confirmed by transmission electron microscopy analysis. The surface of the MNs was modified using 3-aminopropyltriethoxysilane. One weight percent of amine-functionalized MNs (AMNs) improved the impact strength of PP/EVA-g-MA blend matrix, which is about 52%. Melt rheology analysis resulted that the nanocomposite exhibited a viscous behavior up to 2.5 wt % of AMNs and above the content ensued a viscoelastic solid-like behavior. X-ray diffraction analysis showed a complete dispersion of AMNs in the PP/EVA-g-MA blend matrix. TEM analysis confirmed that the MNs sheets are residing mostly in EVA-g-MA phase and the interface of PP/EVA-g-MA blend. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48233.