72 research outputs found
Role of Image-Guided Percutaneous Drainage in Pancreatic Collections
No full textAbstractAcute pancreatitis is one of the major gastrointestinal conditions that lead to around 300,000 hospital admissions per year in the United States. While mild inflammation of the pancreas is often managed conservatively, progression of the disease process to necrosis significantly increases the overall morbidity and mortality and often requires surgical or other interventional techniques for management. The purpose of this review is to describe the role of percutaneous drainage for the management of complicated pancreatitis.</jats:p
NMR studies of silicate and aluminosilicate solutions as precursors for zeolites
No full textThe search for a detailed understanding of the mechanism of zeolite synthesis has, over the past two decades, promoted many investigations into the species present in (alumino)silicate solutions. It is generally accepted that dissolved (alumino)silicate species are involved as precursors in the nucleation of zeolites. Several techniques have been employed to understand the mechanism of formation of these complex structures. NMR spectroscopy has been shown to be a very powerful tool for the detection and characterization of (alumino)silicate species in the solutions in question. This thesis presents a comprehensive study of certain silicate solutions employmg (^29)Si NMR which has extended the knowledge gained in previous studies. The role of structure-direction on the distribution of silicate species in silicate solutions is discussed, the results providing more understanding of this effect. The effects of pH, temperature, Si/cation ratio and silica concentration on the distribution of silicate anions were also studied.Aluminium-27 NMR was applied to investigate the local structure about alummium atoms in a series of alumino silicate solutions with Si:Al mole ratios pertinent to zeolite synthesis. The kinetics of the reaction of aluminate with silicate anions have been studied by investigating the temporal evolutions of (^29)Al NMR spectra and by 2D NMR exchange spectroscopy. Structural analyses of two new silicate crystals were carried out by single-crystal X-ray diffraction. Liquid- and solid-state NMR spectroscopy were employed to characterize the mother liquors, the powdered polycrystalline products, and their melts.The Zeolite SUZ-9 was characterized by application of multinuclear magnetic resonance spectroscopy : (^29)Si, (^27)Al, (^13)C and (^1)H NMR spectra of this zeolite were studied
Comparison of clinical outcome between pyeloperfused versus non-pyeloperfused microwave ablation of renal cell carcinoma
No full textPurpose: We present the outcomes of microwave ablation (MWA) of renal cell carcinoma (RCC) with and without pyeloperfusion. Material and methods: A retrospective review of patients' records was undertaken to identify patients with RCC, who were treated with MWA with and without adjunctive pyeloperfusion. The distance between the tumour and ureter as well as the tumour size were measured on axial imaging. Pyeloperfusion was performed in nine patients in this series after placement of a ureteral stent and instilment of diluted contrast into the ureter. MWAs of the tumours were performed under computed tomography (CT) guidance. Hydrodissection was performed to displace at-risk organs. Creatinine was measured as renal function index after and before the procedure. A CT scan was performed at the end of the procedure and also after one, three, and six months, to identify the presence of residual disease and complications. Results: Eighteen biopsies of proven RCC were treated with 20 sessions of MWA. The average follow-up time for this study was 180 days. The average distance between the ureter and the tumour in axial CT view was 20.8 (± 2.9) mm. Primary efficacy was achieved in 88% of pyeloperfused patients and in 100% of the non-pyeloperfused patients. Two pyeloperfused patients required secondary procedure, and full secondary efficacy was achieved for both. There was only one grade 2 urological complication, which occurred in a patient who underwent pyeloperfusion. Creatinine was not significantly different after the procedure in this study (p-value 0.4). Conclusion: In this study MWAs of RCCs were successfully performed using pyeloperfusion as a protective measure against thermal injury to the ureter
Ureteral protection during microwave ablation of renal cell carcinoma: combined use of pyeloperfusion and hydrodissection
No full textA 56-year-old female with past medical history of thrombotic microangiopathy presented to her physician with nonspecific abdominal pain. A magnetic resonance imaging scan was obtained, which revealed a 3.1 cm mass arising from medial lower pole of the left kidney that was subsequently shown to be renal cell carcinoma by percutaneous biopsy. Because of her history of thrombotic microangiopathy and other comorbidities, she was deemed a nonsurgical candidate and was therefore referred to interventional radiology for thermal ablation. Computed tomography (CT)-guided microwave ablation was performed with the combined use of pyeloperfusion and hydrodissection for maximal ureteral protection. Follow-up unenhanced CT scan obtained one month after ablation showed a normal collecting system without evidence of hydronephrosis or urinoma
Microwave ablation of hepatocellular carcinoma metastatic to peritoneum : diagnostic value of hydrodissection
No full textLarge Scale Solar Power Integration in Distribution Grids: PV Modelling, Voltage Support and Aggregation Studies
No full textLong term supporting schemes for photovoltaic (PV) system installation have led to accommodating large numbers of PV systems within load pockets in distribution grids. High penetrations of PV systems can cause new technical challenges, such as voltage rise due to reverse power flow during light load and high PV generation conditions. Therefore, new strategies are required to address the associated challenges. Moreover, due to these changes in distribution grids, a different response behavior of the distribution grid on the transmission side can be expected. Hence, a new equivalent model of distribution grids with high penetration of PV systems is needed to be addressed for future power system studies. The thesis contributions lie in three parts. The first part of the thesis copes with the PV modelling. A non-proprietary PV model of a three-phase, single stage PV system is developed in PSCAD/EMTDC and PowerFactory. Three different reactive power regulation strategies are incorporated into the models and their behavior are investigated in both simulation platforms using a distribution system with PV systems. In the second part of the thesis, the voltage rise problem is remedied by use of reactive power. On the other hand, considering large numbers of PV systems in grids, unnecessary reactive power consumption by PV systems first increases total line losses, and second it may also jeopardize the stability of the network in the case of contingencies in conventional power plants, which supply reactive power. Thus, this thesis investigates and develops the novel schemes to reduce reactive power flows while still keeping voltage within designated limits via three different approaches: 1. decentralized voltage control to the pre-defined set-points 2. developing a coordinated active power dependent (APD) voltage regulation Q(P) using local signals 3. developing a multi-objective coordinated droop-based voltage (DBV) regulation Q(V) using local signals In the third part of the thesis, furthermore, a gray-box load modeling is used to develop a new static equivalent model of a complex distribution grid with large numbers of PV systems embedded with voltage support schemes. In the proposed model, variations of voltage at the connection point simulate variations of the model’s active and reactive power. This model can simply be integrated into load-flow programs and replace the complex distribution grid, while still keeping the overall accuracy high. The thesis results, in conclusion, demonstrate: i) using rms-based simulations in PowerFactory can provide us with quite similar results using the time domain instantaneous values in PSCAD platform; ii) decentralized voltage control to specific setpoints through the PV systems in the distribution grid is fundamentally impossible due to the high level voltage control interaction and directionality among the PV systems; iii) the proposed APD method can regulate the voltage under the steady-state voltage limit and consume less total reactive power in contrast to the standard characteristic Cosf (P) proposed by German Grid Codes; iv) the proposed optimized DBV method can directly address voltage and successfully regulate it to the upper steady-state voltage limit by causing minimum reactive power consumption as well as line losses; v) it is beneficial to address PV systems as a separate entity in the equivalencing of distribution grids with high density of PV systems.Engineering, Systems and ServicesTechnology, Policy and Managemen
Serving Up Change: A Food Ethics Workshop
No full textDecisions about institutional food procurement take place in several public contexts, including public K-12 schools, public universities, public prisons, and hunger-relief agencies. Food sourcing decisions are often guided by institutional values such as animal welfare, cost, accessibility, convenience, cultural appropriateness, social acceptability, healthfulness, freshness, quality, workers’ rights, localness, and environmental sustainability. At times, these values might not align with the values of constituents of whom these institutions serve. Civic engagement can be used to identify value conflicts, reduce the extent of those conflicts, and find a path to their appropriate resolution. Principled civic engagement practices can also create equitable and inclusive environments in which dialogue can take place. The resulting decisions can benefit in terms of legitimacy, respectfulness, and epistemic soundness. The goal of this workshop is help public school food service directors learn about civic engagement skills so food procurement decisions can become more equitable and just.AUTHOR AFFILIATION: Dan Remley, associate professor and OSU Extension field specialist, [email protected] (Corresponding Author); Glennon Sweeney, senior research associate, Kirwan Institute for the Study of Race and Ethnicity at Ohio State; Karima Samadi, OSU Extension program coordinator; Tannya Forcone, graduate research assistant, Kirwan Institute for the Study of Race and Ethnicity at Ohio StateThis workshop will help nonprofit institutions develop inclusive dialogue with constituents around food values. Partnerships with Extension or public health can facilitate these engagements. At the end of the workshop, individuals will be charged and equipped with leading initiatives in their locale
Bank erosion processes in waterways
No full textWaterways serve for several functions besides transporting goods and people. The ecological importance of navigable rivers has taken much attention during recent decades bringing efforts to improve these natural corridors for fauna and flora (Boeters et al., 1997). Following the policy of the European Water Framework Directive (WFD), many Dutch river reaches have been recently restored through the removal of bank protections in search for better riparian habitats (Florsheim et al., 2009), but they also result exposed to erosive forces. Large uncertainties generally surround the prediction of erosion rates (e.g. Samadi et al., 2009) due to complex flow characteristics in the near-bank region, variable soil properties, etc. A better understanding of bank erosion processes is then of interest to predict erosion rates and improve the design of future interventions. A.J.F. Hoitink, T.V. de Ruijsscher, T.J. Geertsema, B. Makaske, J. Wallinga, J.H.J. Candel, J. Poelman (Eds.) NCR days 2017, Febr. 1-3, 2017. Book of abstracts, NCR publication 41-2017.Rivers, Ports, Waterways and Dredging EngineeringEnvironmental Fluid Mechanic
Investigating The Effect of Transcutaneous Electrical Nerve Stimulation on The Severity of Restless Legs Syndrome in Hemodialysis Patients
No full textBackground and Aim: Restless leg syndrome (RLS) is one of the most common complications of hemodialysis patients. Transcutaneous electrical nerve stimulation (TENS) may affect RLS by reducing pain and increasing blood supply and oxygen supply. The present study was conducted to determine the effect of electrical nerve stimulation through the skin on the severity of restless leg syndrome in hemodialysis patients.
Materials and Methods: This clinical trial study was conducted on 60 patients undergoing hemodialysis treatment in the dialysis department of Vasei Sabzevar and Imam Khomeini Esfrain Hospitals, from December of 2022 to March 2023. The participants were randomly selected in two intervention (30 people) and control groups (30 people). TENS was used with a frequency of 100 Hz in the intervention group and 20 Hz in the control group. The severity of RLS was measured before and after intervention using the RLS questionnaire in two groups. Data analysis was done using SPSS 22 and statistical tests (independent t, paired t-test, and chi-square).
Results: After the intervention, the severity of RLS in the intervention and control groups was 13.93±2.56 and 17.63±3.30, respectively, and the independent t-test showed a significant difference (p=0.001).
Conclusion: The results of this study showed that the use of TENS is effective in relieving of RLS in hemodialysis patients, so it can be used as a complementary method in the treatment of hemodialysis patients
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