253 research outputs found
Audiovisual Biofeedback Improves Cine-Magnetic Resonance Imaging Measured Lung Tumor Motion Consistency.
PURPOSE: To assess the impact of an audiovisual (AV) biofeedback on intra- and interfraction tumor motion for lung cancer patients. METHODS AND MATERIALS: Lung tumor motion was investigated in 9 lung cancer patients who underwent a breathing training session with AV biofeedback before 2 3T magnetic resonance imaging (MRI) sessions. The breathing training session was performed to allow patients to become familiar with AV biofeedback, which uses a guiding wave customized for each patient according to a reference breathing pattern. In the first MRI session (pretreatment), 2-dimensional cine-MR images with (1) free breathing (FB) and (2) AV biofeedback were obtained, and the second MRI session was repeated within 3-6 weeks (mid-treatment). Lung tumors were directly measured from cine-MR images using an auto-segmentation technique; the centroid and outlier motions of the lung tumors were measured from the segmented tumors. Free breathing and AV biofeedback were compared using several metrics: intra- and interfraction tumor motion consistency in displacement and period, and the outlier motion ratio. RESULTS: Compared with FB, AV biofeedback improved intrafraction tumor motion consistency by 34% in displacement (P=.019) and by 73% in period (P<.001). Compared with FB, AV biofeedback improved interfraction tumor motion consistency by 42% in displacement (P<.046) and by 74% in period (P=.005). Compared with FB, AV biofeedback reduced the outlier motion ratio by 21% (P<.001). CONCLUSIONS: These results demonstrated that AV biofeedback significantly improved intra- and interfraction lung tumor motion consistency for lung cancer patients. These results demonstrate that AV biofeedback can facilitate consistent tumor motion, which is advantageous toward achieving more accurate medical imaging and radiation therapy procedures
Detubularized isolated ureterosigmoidostomy in a complicated common cloaca: A case report
Urinary incontinence in a child secondary to a severe congenital anatomical disorder or due to complication of a previous surgery can be difficult to manage. Decisions can be especially hard when a redo procedure is being considered. We present one such case where a 6 year old girl previously operated for cloaca was brought with incontinence and after much consideration of options available, underwent a modified ureterosigmoidostomy to aid in her continence. The modification used was detubularized isolated ureterosigmoidostomy, described by Atta et al in 1996
Feasibility of FSPV-Grid Tied System in Urban Regions of Chhattisgarh State in India
Received: 12 January 2024. Revised: 29 February 2024. Accepted: 8 March 2024. Available online: 31 March 2024.This study presents a novel generation theory based on FSPV system together with grid integration in Chhattisgarh state. In this study four regions mainly two industries and two local loads have been chosen to evaluate the results. There is availability of nearby water sources at the selected sites. The technical, economical and environmental aspects of a proposed FSPV-grid tied system is analyzed in the same selected regions of Chhattisgarh and the results are compared with an existing grid-only system. The entire system of four major sites in the state are simulated using HOMER energy, powered by the National Renewable Energy Laboratory (NREL), United States. At the moment, all of the selected systems are powered by the grid-only system, and data has been collected for the same.
The results of HOMER energy are further classified based on economic parameters such as NPC, LCOE, operating cost, system cost and paybacks. The second category includes technical parameters such as production proportion whereas, the third category includes environmental parameters of pollutants and water saving. The obtained results show that the FSPV-grid system as compared to grid-only system's NPC is reduced to 27%, 7.03%, 10.76%, 12.13%, LCOE is reduced to 69%, 27.8%, 44%, 44.6%, with paybacks of 10.11 years, 12.28 years, 11.99 years, and 12.21 years and IRRs of 8.8%, 7.7%, 8%, 7.7% respectively by following the production proportions of 77.7% and 22.3%, 54.2% and 45.8%, 65.2% and 34.8%, and 65% and 35% from FSPV and grid system, Also, CO2 emissions were reduced by 44.6%, 38.06%, 40.62%, and 41.23% compared to the gridonly system for all four selected sites in this study, which can help the attached industries and local loads gain carbon credit points
Octreotide in Intestinal Lymphangiectasia: Lack of a Clinical Response and Failure to Alter Lymphatic Function in a Guinea Pig Model
Intestinal lymphangiectasia, which can be classified as primary or secondary, is an unusual cause of protein-losing enteropathy. The main clinical features include edema, fat malabsorption, lymphopenia and hypoalbuminemia. Clinical management generally includes a low-fat diet and supplementation with medium chain triglycerides. A small number of recent reports advocate the use of octreotide in intestinal lymphangiectasia. It is unclear why octreotide was used in these studies; although octreotide can alter splanchnic blood flow and intestinal motility, its actions on lymphatic function has never been investigated. A case of a patient with intestinal lymphangiectasia who required a shunt procedure after failing medium chain triglycerides and octreotide therapy is presented. During the management of this case, all existing literature on intestinal lymphangiectasia and all the known actions of octreotide were reviewed. Because some of the case reports suggested that octreotide may improve the clinical course of intestinal lymphangiectasia by altering lymphatic function, a series of experiments were undertaken to assess this. In an established guinea pig model, the role of octreotide in lymphatic function was examined. In this model system, the mesenteric lymphatic vessels responded to 5-hydroxytryptamine with a decrease in constriction frequency, while histamine administration markedly increased lymphatic constriction frequency. Octreotide failed to produce any change in lymphatic function when a wide range of concentrations were applied to the mesenteric lymphatic vessel preparation. In conclusion, in this case, octreotide failed to induce a clinical response and laboratory studies showed that octreotide did not alter lymphatic function. Thus, the mechanisms by which octreotide induced clinical responses in the cases reported elsewhere in the literature remain unclear, but the present study suggests that it does not appear to act via increasing lymphatic pumping
Impact of audiovisual biofeedback on interfraction respiratory motion reproducibility in liver cancer stereotactic body radiotherapy.
INTRODUCTION: Irregular breathing motion exacerbates uncertainties throughout a course of radiation therapy. Breathing guidance has demonstrated to improve breathing motion consistency. This was the first clinical implementation of audiovisual biofeedback (AVB) breathing guidance over a course of liver stereotactic body radiotherapy (SBRT) investigating interfraction reproducibility. METHODS: Five liver cancer patients underwent a screening procedure prior to CT sim during which patients underwent breathing conditions (i) AVB, or (ii) free breathing (FB). Whichever breathing condition was more regular was utilised for the patient's subsequent course of SBRT. Respiratory motion was obtained from the Varian respiratory position monitoring (RPM) system (Varian Medical Systems). Breathing motion reproducibility was assessed by the variance of displacement across 10 phase-based respiratory bins over each patient's course of SBRT. RESULTS: The screening procedure yielded the decision to utilise AVB for three patients and FB for two patients. Over the course of SBRT, AVB significantly improved the relative interfraction motion by 32%, from 22% displacement difference for FB patients to 15% difference for AVB patients. Further to this, AVB facilitated sub-millimetre interfraction reproducibility for two AVB patients. CONCLUSION: There was significantly less interfraction motion with AVB than FB. These findings demonstrate that AVB is potentially a valuable tool in ensuring reproducible interfraction motion
Thirty Years After Michael E. Porter: What Do We Know About Business Exit?
Although a business exit is an important corporate change initiative, the buyer’s side seems to be more appealing to management researchers than the seller’s because acquisitions imply growth, i.e., success. Yet from an optimistic viewpoint, business exit can effectively create value for the selling company. In this paper we attempt to bring the relevance of the seller’s side back into our consciousness by asking: What do we know about business exit? We start our exploration with Porter (1976), focusing on literature that investigates the antecedents of, barriers to, and outcomes of business exit. We also include studies from related fields such as finance and economics.1 Through this research we determine three clusters of findings: factors promoting business exit, exit barriers, and exit outcomes. Overall, it is the intention of this paper to highlight the importance of business exit for research and practice. Knowing what we know about business exits and their high financial value we should bear in mind that exit need not mean failure but a new beginning for a corporation
Razvoj i vrednovanje dvoslojnih tableta propranolol hidroklorida
The objective of the present research was to develop a bilayer tablet of propranolol hydrochloride using superdisintegrant sodium starch glycolate for the fast release layer and water immiscible polymers such as ethyl cellulose, Eudragit RLPO and Eudragit RSPO for the sustaining layer. In vitro dissolution studies were carried out in a USP 24 apparatus I. The formulations gave an initial burst effect to provide the loading dose of the drug followed by sustained release for 12 hrs from the sustaining layer of matrix embedded tablets. In vitro dissolution kinetics followed the Higuchi model via a non-Fickian diffusion controlled release mechanism after the initial burst release. FT-IR studies revealed that there was no interaction between the drug and polymers used in the study. Statistical analysis (ANOVA) showed no significant difference in the cumulative amount of drug release after 15 min, but significant difference (p 0.005) in the amount of drug released after 12 h from optimized formulations was observed.U radu je opisan razvoj dvoslojnih tableta propranolol hidroklorida, koristeći superdezintegrator škrob glikolat natrij u sloju za brzo oslobađanje i polimere koji se ne miješaju s vodom (etil celuloza, Eudragit RLPO i Eudragit RSPO) u sloju za usporeno oslobađanje. In vitro oslobađanje praćeno je u USP aparatu I te je uočeno početno naglo oslobađanje ljekovite tvari iza kojeg slijedi polagano oslobađanje tijekom 12 sati. In vitro kinetika oslobađanja prati Higouchijev model, dok mehanizam kontroliranog oslobađanja ne slijedi Fickov zakon poslije početnog naglog oslobađanja. FT-IR studije ukazuju da nema interakcije između ljekovite tvari i polimera upotrebljenih u oblikovanju. Statistička analiza (ANOVA) nije pokazala značajne razlike u kumulativnoj količini oslobođenog lijeka iz optimiranih formulacija poslije 15 minuta i polije 12 h
Practices participating in a dental PBRN have substantial and advantageous diversity even though as a group they have much in common with dentists at large
<p>Abstract</p> <p>Background</p> <p>Practice-based research networks offer important opportunities to move recent advances into routine clinical practice. If their findings are not only generalizable to dental practices at large, but can also elucidate how practice characteristics are related to treatment outcome, their importance is even further elevated. Our objective was to determine whether we met a key objective for The Dental Practice-Based Research Network (DPBRN): to recruit a diverse range of practitioner-investigators interested in doing DPBRN studies.</p> <p>Methods</p> <p>DPBRN participants completed an enrollment questionnaire about their practices and themselves. To date, more than 1100 practitioners from the five participating regions have completed the questionnaire. The regions consist of: Alabama/Mississippi, Florida/Georgia, Minnesota, Permanente Dental Associates, and Scandinavia (Denmark, Norway, and Sweden). We tested the hypothesis that there are statistically significant differences in key characteristics among DPBRN practices, based on responses from dentists who participated in DPBRN's first network-wide study (n = 546).</p> <p>Results</p> <p>There were statistically significant, substantive regional differences among DPBRN-participating dentists, their practices, and their patient populations.</p> <p>Conclusion</p> <p>Although as a group, participants have much in common with practices at large; their substantial diversity offers important advantages, such as being able to evaluate how practice differences may affect treatment outcomes, while simultaneously offering generalizability to dentists at large. This should help foster knowledge transfer in both the research-to-practice and practice-to-research directions.</p
Dominant activating RAC2 mutation with lymphopenia, immunodeficiency, and cytoskeletal defects
Ras-related C3 botulinum toxin substrate 2 (RAC2), through interactions with reduced NAD phosphate oxidase component p67 phox , activates neutrophil superoxide production, whereas interactions with p21-activated kinase are necessary for fMLF-induced actin remodeling. We identified 3 patients with de novo RAC2[E62K] mutations resulting in severe T- and B-cell lymphopenia, myeloid dysfunction, and recurrent respiratory infections. Neutrophils from RAC2[E62K] patients exhibited excessive superoxide production, impaired fMLF-directed chemotaxis, and abnormal macropinocytosis. Cell lines transfected with RAC2[E62K] displayed characteristics of active guanosine triphosphate (GTP)-bound RAC2 including enhanced superoxide production and increased membrane ruffling. Biochemical studies demonstrated that RAC2[E62K] retains intrinsic GTP hydrolysis; however, GTPase-activating protein failed to accelerate hydrolysis resulting in prolonged active GTP-bound RAC2. Rac2+/E62K mice phenocopy the T- and B-cell lymphopenia, increased neutrophil F-actin, and excessive superoxide production seen in patients. This gain-of-function mutation highlights a specific, nonredundant role for RAC2 in hematopoietic cells that discriminates RAC2 from the related, ubiquitous RAC1
Divide and Privatize: Firms Break-Up and Performance
We analyze the long-term effects of divesture and ownership change on corporate performance. We employ a unique data set for a large number of Czech firms spanning the period 1996-2005. We employ a propensity score matching procedure to deal with endogeneity problems. Our results, which are generally in line with the positive effects of divestiture found in the developed-market literature, show that the initial effects of divestiture are positive but after a certain point they quickly diminish over time
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