Migration of forgotten stent into renal pelvis

Stent migration is a well recognized complication of forgotten stents, but migration into the renal pelvis is rarely documented. We present a case of migration and coiling of a forgotten stent in the renal pelvis, and discuss briefly, the etiological factors for the phenomenon and associated problems in management

Analysis and MPPT control of a wind-driven three-phase induction generator feeding single-phase utility grid

In this study, a three-phase diode bridge rectifier and a single-phase voltage source inverter topology has been proposed for feeding single-phase utility grid employing a three-phase induction generator fed from wind energy. A self-excited induction generator configuration has been chosen for wide speed operation of wind turbine system, which gives the scope for extracting maximum power available in the wind. In addition to maximum power point tracking (MPPT), the generator can be loaded to its rated capacity for feeding single-phase utility grid using a three-phase induction machine, whereas it is not possible with existing configurations because of the absence of power converters. For the proposed system, MPPT algorithm has been devised by continuously monitoring the grid current and a proportional resonant controller has been employed for grid synchronisation of voltage source inverter with single-phase grid. A MATLAB/Simulink model of the proposed system has been developed to ascertain its successful working by predetermining the overall performance characteristics. The present proposal has also been tested with sag, swell and distortion in the grid voltage. The control strategy has been implemented using field programmable gate array (FPGA) controller with modularised programming approach. The efficacy of the system has been demonstrated with the results obtained from an experimental set-up in the laboratory

Latent tuberculosis infection and renal transplantation – Diagnosis and management

Background: Tuberculosis (TB) continues to be the commonest infectious disease cause of death worldwide. Tuberculosis is an important infectious disease cause of morbidity and death in renal transplant recipients. Tuberculosis can also cause loss of kidney allograft. Objectives: The purpose of this viewpoint is to highlight the issues related to prevention, diagnosis and treatment of tuberculosis in renal transplant recipients. Methods: The PubMed database was searched for publications and guidelines on diagnosis and management of LTBI in renal transplantation. Publications on renal allograft recipients with LTBI and TB in post-operative period were also analysed. Specialist Society guidelines were also used. Findings: Tuberculosis is one of the most important infectious disease-related causes of morbidity and death in transplant recipients. LTBI in allograft recipients continues to be a clinical management problem. It can occur either from donor kidney or from endogenous reactivation of latent tuberculosis infection or from acquiring new Mycobacterium tuberculosis infection. Tuberculosis can also cause loss of kidney allograft. Conclusions: Kidney transplantation is now universally performed in high and low Tuberculosis endemic countries. A high index of awareness of the possibility of TB disease or LTBI is required prior to renal transplant aligned to reduce renal allograft damage, morbidity and death due to tuberculosis. WHO Management recommendations for LTBI screening and treatment should be followed. Keywords: Latent tuberculosis infection (LTBI), Renal transplantation, Interferon gamma assay, Tuberculin skin test, Allograft, Immune suppressio

Wind-driven SEIG supplying DC microgrid through a single-stage power converter

Nowadays, there is an increased emphasis on utilizing the renewable energy sources and selection of suitable power converters for supplying dc microgrid. Among the various renewable energy sources, wind energy stands first in terms of installed capacity. So, an attempt is made in this paper for supplying dc microgrid utilizing wind energy. A self-excited induction generator has been used in the proposed wind energy conversion system (WECS). A single-stage power converter, namely, semi-converter is connected between the SEIG and dc grid terminals for closed-loop control of the proposed system. A perturb and observe (P&O) based maximum power point tracking (MPPT) algorithm has been developed and implemented using a dsPIC30F4011 digital controller. In this MPPT algorithm, the firing angle of the converter is adjusted by continuously monitoring the dc grid current for a given wind velocity. For analyzing the proposed system, a MATLAB/Simulink model has been developed by selecting the various components starting from wind-turbine model to the power converter supplying dc microgrid. Successful working of the proposed WECS has also been shown through experimental results obtained on a prototype model developed in the laboratory

Comparison of Pneumatic Vs Holmium Yag Laser in Proximal Ureteral Stones-A Retrospective Observational Study

Introduction: Global prevalence of urolithiasis is approximately 14%, which varies depending upon age, gender, geographical location, and ethnicity.Upper urinary tract constitutes majority of stone burden, only 5% of stones are found within the bladder.Urolithiasis presents a significant economic burden on the healthcare systems across the world.Materials and Methods: A retrospective observational study was conducted at Department of Urology and Renal Transplantation, Sri Ramachandra Institute of Higher Education and Research (SRIHER), Chennai,India Demographic details of patients, history and physical examination findings, biochemical evaluation (serum creatinine, blood urea nitrogen), urinalysis, and urine culture sensitivity test results, duration of surgery, duration of hospital stay, stone migration, stone recurrence, and complication were recorded from the case files.Results: mean age of the patients in pneumatic lithotripsy group was 41.58±12.66 and in laser Lithotripsy group was 45.12±11.16. Independent-t-test was computed to find the significant mean difference between the groups. It revealed that there is no statistically significant mean difference found between the both groups regarding age. Hence both groups were similar. The mean operation time(minutes) of the patients in pneumatic lithotripsy group was 24.00±7.56 and in laser Lithotripsy group was 23.73±6.39. Independent-t-test was computed to find the significant mean difference between the groups. It revealed there is no statistically significant mean difference found between the both groups regarding operation time (minutes).Conclusion: Holmium laser is costly, less commonly available while pneumatic is cheap and widely used. Our study, establishes the supremacy of HO:YAG laser over pneumatic lithotripsy in proximal ureteric calculi and should be preferred modality, if it is available and economically feasible

Testicular leiomyosarcoma with metastasis

Primary leiomyosarcoma of testis is a rare entity with few cases reported in literature. Primary leiomyosarcoma of testis usually occurs following radiotherapy or long-term anabolic steroid use. Without these predisposing factors, its occurrence is rare. In the present study, we present a rare case of primary leiomyosarcoma of testis occurring in an elderly patient, with an unusual presentation mimicking epididymo-orchitis and metastasis eight months following high inguinal orchidectomy

Analysis and control of induction generator supplying stand-alone AC loads employing a Matrix Converter

This paper proposes a Capacitor Excited Induction Generator (CEIG)-Matrix Converter (MC) system for feeding stand-alone AC loads. The variable output voltage magnitude and frequency from CEIG is converted into a constant voltage magnitude and frequency at the load terminals by controlling MC using Space Vector Modulation (SVM) technique. This single-stage MC is turned up as a good alternative for the proposed system against commonly used AC/DC/AC two stage power converters. The configuration and implementation of the closed-loop control scheme employing dSPACE 1103 real time controller have been fully described in the paper. The proposed closed-loop controller regulates the AC load voltage irrespective of changes in the prime mover speed and load. A method for predetermining the steady-state performance of the proposed system has been developed and described with relevant analytical expressions. The effectiveness of the proposed system is exemplified through simulation results for various operating conditions. The proposed control technique is further validated using an experimental setup developed in the laboratory