The study of dispersion by indicator dilution techniques in blood and other fluids flowing through tubes and bifurcating networks

Imperial Users onl

Optimalus galios paskirstymas mikrotinkle

Internationally, power demand is booming so, renewable energy based distributed generator and Microgrid spider network will increasingly play a decisive role in electricity production, distribution and most advantageous level power sharing. A Microgrid comprises of various sort of load and disseminated generators that work as a solitary controllable framework. Presently a day, control gadgets are on edge about wellbeing when the utility network associated with Microgrid or other inexhaustible assets at interconnected or islanded mode. The main goal of this thesis is to inspect and propose using a multi-input DC-DC power converter for grid connected hybrid Microgrid system to reduce the cost and share the power at optimal level. In the system, it consists of the multi-input DC-DC converter and full-bridge DC-AC IGBT inverter. If the fluctuation is more in the output of renewable energy resources than maximum power point tracking algorithm is used by input sources of PV and the wind. The integration of DC bus and Hybrid Microgrid renewable power supply system implemented and simulated using MATLAB/SIMULINK as compared to use directly AC bus. Methods that have been used to control stability in Microgrid by load sharing are analysed in this thesis. Also in this thesis, a price-based demand response is proposed using to share power in Microgrid. By utilizing this technique it is less demanding to keep up security amongst request and era. It is an imperative about dynamic and receptive power control in the power framework, particularly when the diverse sort of Microgrid sustainable power source assets associated with the utility network. As a result, how the modelling of the power grid infrastructure with Microgrid connected renewable energy resources are controlled and discussed here and the result of controlling load, frequency, voltage and current are achieved here. On the basis of parameters results the power sharing is possible at optimal level with system balancing and reduce the cost

Bland embolization of benign liver tumors: Review of the literature and a single center experience

Transarterial embolization has shown promise as a safe, effective, and less invasive treatment modality for benign liver lesions (hemangioma, focal nodular hyperplasia (FNH), and hepatic adenoma (HA)) with fewer complications compared to surgical intervention. There is no consensus regarding the most appropriate embolization material(s) for the treatment of benign liver tumors. The purpose of this study was to review the current literature regarding the transarterial embolization of benign liver tumors and to share our single center experience. This was a non-blinded, retrospective, single-institution review of the bland embolization of benign liver tumors. Clinical data and imaging before and after embolization were used to evaluate lesion response to transarterial embolization. Twelve patients were included in the study. Five patients with six hemangiomas were treated. Pain was a presenting complaint in all five of these patients. The median change in tumor volume was -12.4% and ranged from -30.1% to +42.3%. One patient with two FNH lesions was treated, and both lesion volumes decreased by more than 50%. Six patients with 10 adenomas were treated. Pain was a presenting complaint in three patients, and five patients had a lesion \u3e5 cm. The median change in tumor volume was -67.0% and ranged from -92.9% to +65.8%. Bland transarterial embolization of liver hemangiomas, FNH, and HA can be an effective and minimally invasive treatment modality to control the size and/or symptoms of these lesions. There is a variable response depending on tumor type and the embolization materials used

Coblation for metastatic vertebral disease

PURPOSEPlasma-mediated radiofrequency ablation (coblation) creates a cavity for directed polymethylmethacrylate deposition through molecular dissociation, providing a safe and efficacious cementoplasty for patients with high-risk, painful vertebral body metastatic disease. The purpose of this study was to retrospectively review and report details regarding the feasibility, safety, and efficacy of coblation and cementoplasty for treating painful advanced vertebral body metastatic disease.MATERIALS AND METHODSFifteen patients with painful metastatic vertebral body fractures with a posterior cortical defect and/or epidural tumor extension underwent percutaneous coblation and cementoplasty. Each patient’s medical record was reviewed for technical success, imaging outcome, complications, and palliative effect.RESULTSOf the 15 cases, 14 were completed successfully. Postprocedure imaging studies demonstrated adequate cement deposition within the targeted vertebral body without cement extravasation or fracture progression during the 1–3 months follow-up period. Pain relief was achieved in all patients, and no neurological damage was reported (mean follow-up, 141.1±132.5 days).CONCLUSIONPercutaneous image-guided coblation-mediated cavity creation prior to vertebroplasty allows for safe, efficacious cement deposition in patients with metastatic foci. Future studies prospectively comparing this procedure with other standard-of-care regimens are warranted

Gastrointestinal bleeding detection on digital subtraction angiography using convolutional neural networks with and without temporal information

PURPOSE: Digital subtraction angiography (DSA) offers a real-time approach to locating lower gastrointestinal (GI) bleeding. However, many sources of bleeding are not easily visible on angiograms. This investigation aims to develop a machine learning tool that can locate GI bleeding on DSA prior to transarterial embolization. METHODS: All mesenteric artery angiograms and arterial embolization DSA images obtained in the interventional radiology department between January 1, 2007, and December 31, 2021, were analyzed. These images were acquired using fluoroscopy imaging systems (Siemens Healthineers, USA). Thirty-nine unique series of bleeding images were augmented to train two-dimensional (2D) and three-dimensional (3D) residual neural networks (ResUNet++) for image segmentation. The 2D ResUNet++ network was trained on 3,548 images and tested on 394 images, whereas the 3D ResUNet++ network was trained on 316 3D objects and tested on 35 objects. For each case, both manually cropped images focused on the GI bleed and uncropped images were evaluated, with a superimposition post-processing (SIPP) technique applied to both image types. RESULTS: Based on both quantitative and qualitative analyses, the 2D ResUNet++ network significantly outperformed the 3D ResUNet++ model. In the qualitative evaluation, the 2D ResUNet++ model achieved the highest accuracy across both 128 × 128 and 256 × 256 input resolutions when enhanced with the SIPP technique, reaching accuracy rates between 95% and 97%. However, despite the improved detection consistency provided by SIPP, a reduction in Dice similarity coefficients was observed compared with models without post-processing. Specifically, the 2D ResUNet++ model combined with SIPP achieved a Dice accuracy of only 80%. This decline is primarily attributed to an increase in false positive predictions introduced by the temporal propagation of segmentation masks across frames. CONCLUSION: Both 2D and 3D ResUNet++ networks can be trained to locate GI bleeding on DSA images prior to transarterial embolization. However, further research and refinement are needed before this technology can be implemented in DSA for real-time prediction. CLINICAL SIGNIFICANCE: Automated detection of GI bleeding in DSA may reduce time to embolization, thereby improving patient outcomes

Establishing a telemedicine program for interventional radiology: a study of patient opinion and experience

PURPOSEThe COVID-19 pandemic forced healthcare officials to implement new policies, such as the use of virtual consultations over office-based medical appointments, to reduce the transmission of the virus. The purpose of this study is to quantitatively compare patients’ experiences with virtual outpatient telemedicine encounters at a single academic institution in Interventional Radiology (IR) and in-person visits during the course of the COVID-19 pandemic. METHODSThe TeleENT Satisfaction Questionnaire and the Medical Communication Competence Scale (MCCS) were used to survey patients’ satisfaction with both in-person and virtual office visits. RESULTSNinety respondents (38 in-person, 52 virtual) acknowledged numerous benefits of virtual visits versus in-person office visits including reductions in time, cost, and potential viral transmission risk during the COVID-19 pandemic. No statistically significant difference was noted, based on a Likert scale from 1 to 7, between in-person and virtual visits (all p > 0.05) for scheduling related factors. No statistically significant difference was noted in any of the MCCS subscales between the two cohorts in regards to medical information communication (all p > 0.05). A majority of patients with virtual encounters (82.7%) stated that it was easy to obtain an electronic device for use during the telemedicine visit, and 73.1% of patients felt that setting up the telemedicine encounter was easy.CONCLUSIONThis study demonstrates that telemedicine is an acceptable alternative to in-office appointments and could increase access to IR care outside of the traditional physician-patient interaction. With telemedicine visits, patients can communicate their concerns and obtain information from the doctor with noninferior communication compared to in-person visits

Concomitant Use of Single Antiplatelet Therapy With Edoxaban or Warfarin in Patients With Atrial Fibrillation: Analysis From the ENGAGE AF‐TIMI48 Trial

Background: We studied the concomitant use of single antiplatelet therapy (SAPT) on the efficacy and safety of the anti‐Xa agent edoxaban in patients with atrial fibrillation (AF). Methods and Results: ENGAGE AF‐TIMI 48 was a randomized trial that compared 2 dose regimens of edoxaban with warfarin. We studied both the approved high‐dose edoxaban regimen (HDER; 60 mg daily reduced by one half in patients with anticipated increased drug exposure), as well as a lower‐dose edoxaban regimen (LDER; 30 mg daily, also reduced by one half in patients with anticipated increased drug regimen). SAPT (aspirin in 92.5%) was administered at the discretion of the treating physician. Cox proportional hazard regressions stratified by SAPT at 3 months with treatment as a covariate were performed. The 4912 patients who received SAPT were more frequently male, with histories of coronary artery disease and diabetes, and had higher CHADS 2Vasc and HAS BLED scores than did the 14 977 patients not receiving SAPT. When compared to patients not receiving SAPT, those receiving SAPT had a higher incidence of major bleeding; (adjusted hazard ratio [HR adj]=1.46; 95% CI, 1.27–1.67, P<0.001). SAPT did not alter the relative efficacy of edoxaban compared to warfarin in preventing stroke or systemic embolic events (SEEs): edoxaban versus warfarin without SAPT, hazard ratio (HR adj for HDER)=0.94; (95% CI: 0.77–1.15) with SAPT, HR adj=0.70 (95% CI: 0.50–0.98), P interaction (P int)=0.14. (HR adj for LDER versus warfarin without SAPT=1.19 (95% CI 0.99–1.43) With SAPT, 1.03 (95% CI, 0.76–1.39) P int=0.42. Major bleeding was lower with edoxaban than warfarin both without SAPT, HR adj for HDER=0.80 (95% CI, 0.68–0.95), and with SAPT, HR adj=0.82 (95% CI, 0.65–1.03; P int=0.91). For LDER without SAPT (HR adj=0.56 [95% CI 0.46–0.67]) and with SAPT (HR adj=0.51 [95% CI 0.39–0.66]). Conclusions: Patients with AF who were selected by their physicians to receive SAPT in addition to an anticoagulant had a similar risk of stroke/SEE and higher rates of bleeding than those not receiving SAPT. Edoxaban exhibited similar relative efficacy and reduced bleeding compared to warfarin, with or without concomitant SAPT. Clinical Trial Registration URL: http://www.clinicaltrials.gov/. Unique identifier: NCT00781391

Optimalus galios paskirstymas mikrotinkle.

Internationally, power demand is booming so, renewable energy based distributed generator and Microgrid spider network will increasingly play a decisive role in electricity production, distribution and most advantageous level power sharing. A Microgrid comprises of various sort of load and disseminated generators that work as a solitary controllable framework. Presently a day, control gadgets are on edge about wellbeing when the utility network associated with Microgrid or other inexhaustible assets at interconnected or islanded mode. The main goal of this thesis is to inspect and propose using a multi-input DC-DC power converter for grid connected hybrid Microgrid system to reduce the cost and share the power at optimal level. In the system, it consists of the multi-input DC-DC converter and full-bridge DC-AC IGBT inverter. If the fluctuation is more in the output of renewable energy resources than maximum power point tracking algorithm is used by input sources of PV and the wind. The integration of DC bus and Hybrid Microgrid renewable power supply system implemented and simulated using MATLAB/SIMULINK as compared to use directly AC bus. Methods that have been used to control stability in Microgrid by load sharing are analysed in this thesis. Also in this thesis, a price-based demand response is proposed using to share power in Microgrid. By utilizing this technique it is less demanding to keep up security amongst request and era. It is an imperative about dynamic and receptive power control in the power framework, particularly when the diverse sort of Microgrid sustainable power source assets associated with the utility network. As a result, how the modelling of the power grid infrastructure with Microgrid connected renewable energy resources are controlled and discussed here and the result of controlling load, frequency, voltage and current are achieved here. On the basis of parameters results the power sharing is possible at optimal level with system balancing and reduce the cost

Evaluation of springback prediction capability using uniform pure bending

Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering"May 2006."Includes bibliographic references (leaves 52-54)The aim of this study is to develop uniform pure bending as an objective test for determining the accuracy of springback prediction by employing different FEA techniques. A complete theoretical solution for the bending moment and change in sheet thickness is available only for uniform pure bending of perfectly plastic sheets. However, plastic hinging develops naturally in simulations of bending perfectly plastic sheets. We have developed a method to prevent plastic hinging and achieve uniform pure bending of sheets by applying constraint equations to nodes along the center fiber. The error in the bending moment for forming (E1), the error due to incomplete unloading during springback (E2), and error in the change of curvature corresponding to the change in bending moment during unloading (E3) are considered independently to get insights into the reasons for discrepancies between finite element analysis and theoretical results for springback. Uniform pure bending is also used to study the bending moment and springback experienced with work-hardening materials. Comparisons have been made with analytical solutions containing minor approximations in terms of the behavior of the material near the center fiber, which is subject to reverse loading. The fact that two different theoretical models for the material undergoing reverse deformation yield results that differ by less than 1% leads to a high degree of confidence in the theoretical models. We have used uniform pure bending to study the inherent springback prediction capability of different types of element analysis, convergence parameters, and discretization level in two different finite element analysis packages, namely MARC and ABAQUS. For simulations in ABAQUS using two dimensional elements and a perfectly plastic material model, the bending moment given by FEA is less than that predicted by the theoretical model by about -3%, indicating lesser springback than that predicted by theory. However for three dimensional elements, the bending moment is higher by about 10% for a relative curvature (%) of 0.2. For a coarse discretization (about 4 elements around a 90° bend), this error increases to about 37%. For a work-hardening material model, two dimensional elements predict 12% less bending moment than the theory, indicating an under-prediction in springback. Shell elements with reduced integration give an under-prediction of springback and show a negative error value between 2% and 10% for the simulations with different integration points, while shell with full integration show a positive total error of abut 3%, indicating a higher springback than predicted by theory. Changing the convergence tolerance value by 100 from the default value shows a 2% change in calculated results. For MARC, the two dimensional elements under-predicts springback by 10%, while the three dimensional elements have shown over-prediction up to 30% in moment calculations. Based on the findings, uniform pure bending is recommended as a benchmark test for identifying the intrinsic accuracy with which springback can be predicted by FEA simulations using different simulation parameters. Uniform pure bending can be used to develop effective guidelines for reliable finite element simulations of springback