241 research outputs found

    Evaluation of Subepithelial Abnormalities of the Appendix by Endoscopic Ultrasound

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    Background. The use of through-the-scope (TTS) miniprobe catheter endoscopic ultrasound is a valuable technique for evaluating subepithelial lesions in the proximal colon. Few reports include the evaluation of the appendix by EUS. Objective. To describe endoscopic and endosonographic characteristics of subepithelial lesions of the appendix. Methods. Retrospective case series in a single academic medical center. Adult patients referred for evaluation of subepithelial lesions of the appendix identified by colonoscopy between April 1, 2003 to February 29, 2008. Data were abstracted from an electronic endoscopic database for all patients undergoing miniprobe endoscopic ultrasound examination of the appendix. Medical records were reviewed for patient followup and outcomes. Results. Nine cases were identified. Seven (78%) patients were female. Seven (78%) utilized the 12 MHz miniprobe device and two (22%) used the 20 MHz device. Three mucoceles were described and confirmed by surgical resection. Cases also included one inverted appendix, one gastrointestinal stromal tumor, and one lipoma. In three cases, no abnormality was found. Conclusions. EUS evaluation of the appendix is feasible with standard miniprobe devices and may assist in the selection of patients who may benefit from surgical management

    Quality of Life in Chronic Pancreatitis is Determined by Constant Pain, Disability/Unemployment, Current Smoking, and Associated Co-Morbidities

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    OBJECTIVES: Chronic pancreatitis (CP) has a profound independent effect on quality of life (QOL). Our aim was to identify factors that impact the QOL in CP patients. METHODS: We used data on 1,024 CP patients enrolled in the three NAPS2 studies. Information on demographics, risk factors, co-morbidities, disease phenotype, and treatments was obtained from responses to structured questionnaires. Physical and mental component summary (PCS and MCS, respectively) scores generated using responses to the Short Form-12 (SF-12) survey were used to assess QOL at enrollment. Multivariable linear regression models determined independent predictors of QOL. RESULTS: Mean PCS and MCS scores were 36.7+/-11.7 and 42.4+/-12.2, respectively. Significant (P \u3c 0.05) negative impact on PCS scores in multivariable analyses was noted owing to constant mild-moderate pain with episodes of severe pain or constant severe pain (10 points), constant mild-moderate pain (5.2), pain-related disability/unemployment (5.1), current smoking (2.9 points), and medical co-morbidities. Significant (P \u3c 0.05) negative impact on MCS scores was related to constant pain irrespective of severity (6.8-6.9 points), current smoking (3.9 points), and pain-related disability/unemployment (2.4 points). In women, disability/unemployment resulted in an additional 3.7 point reduction in MCS score. Final multivariable models explained 27% and 18% of the variance in PCS and MCS scores, respectively. Etiology, disease duration, pancreatic morphology, diabetes, exocrine insufficiency, and prior endotherapy/pancreatic surgery had no significant independent effect on QOL. CONCLUSIONS: Constant pain, pain-related disability/unemployment, current smoking, and concurrent co-morbidities significantly affect the QOL in CP. Further research is needed to identify factors impacting QOL not explained by our analyses

    Magic Numbers and Optical Absorption Spectrum in Vertically Coupled Quantum Dots in the Fractional Quantum Hall Regime

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    Exact diagonalization is used to study the quantum states of vertically coupled quantum dots in strong magnetic fields. We find a new sequence of angular momentum magic numbers which are a consequence of the electron correlation in the double dot. The new sequence occurs at low angular momenta and changes into the single dot sequence at a critical angular momentum determined by the strength of the inter-dot electron tunneling. We also propose that the magic numbers can be investigated experimentally in vertically coupled dots. Because of the generalized Kohn theorem, the far-infrared optical absorption spectrum of a single dot is unaffected by correlation but the theorem does not hold for two vertically coupled dots which have different confining potentials. We show that the absorption energy of the double dot should exhibit discontinuities at the magnetic fields where the total angular momentum changes from one magic number to another.Comment: 4 pages, 3 Postscript figures, RevTeX. (to appear in Phys.Rev.B

    Mechanisms of CFTR Functional Variants That Impair Regulated Bicarbonate Permeation and Increase Risk for Pancreatitis but Not for Cystic Fibrosis

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    CFTR is a dynamically regulated anion channel. Intracellular WNK1-SPAK activation causes CFTR to change permeability and conductance characteristics from a chloride-preferring to bicarbonate-preferring channel through unknown mechanisms. Two severe CFTR mutations (CFTRsev) cause complete loss of CFTR function and result in cystic fibrosis (CF), a severe genetic disorder affecting sweat glands, nasal sinuses, lungs, pancreas, liver, intestines, and male reproductive system. We hypothesize that those CFTR mutations that disrupt the WNK1-SPAK activation mechanisms cause a selective, bicarbonate defect in channel function (CFTRBD) affecting organs that utilize CFTR for bicarbonate secretion (e.g. the pancreas, nasal sinus, vas deferens) but do not cause typical CF. To understand the structural and functional requirements of the CFTR bicarbonate-preferring channel, we (a) screened 984 well-phenotyped pancreatitis cases for candidate CFTRBD mutations from among 81 previously described CFTR variants; (b) conducted electrophysiology studies on clones of variants found in pancreatitis but not CF; (c) computationally constructed a new, complete structural model of CFTR for molecular dynamics simulation of wild-type and mutant variants; and (d) tested the newly defined CFTRBD variants for disease in non-pancreas organs utilizing CFTR for bicarbonate secretion. Nine variants (CFTR R74Q, R75Q, R117H, R170H, L967S, L997F, D1152H, S1235R, and D1270N) not associated with typical CF were associated with pancreatitis (OR 1.5, p = 0.002). Clones expressed in HEK 293T cells had normal chloride but not bicarbonate permeability and conductance with WNK1-SPAK activation. Molecular dynamics simulations suggest physical restriction of the CFTR channel and altered dynamic channel regulation. Comparing pancreatitis patients and controls, CFTRBD increased risk for rhinosinusitis (OR 2.3, p<0.005) and male infertility (OR 395, p<<0.0001). WNK1-SPAK pathway-activated increases in CFTR bicarbonate permeability are altered by CFTRBD variants through multiple mechanisms. CFTRBD variants are associated with clinically significant disorders of the pancreas, sinuses, and male reproductive system.Fil: LaRusch, Jessica. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Jung, Jinsei. Yonsei University College of Medicine; Corea del SurFil: General, Ignacio. University of Pittsburgh; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lewis, Michele D.. Mayo Clinic. Division of Gastroenterology and Hepatology; Estados UnidosFil: Park, Hyun Woo. Yonsei University College of Medicine; Corea del SurFil: Brand, Randall E.. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Gelrud, Andres. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Anderson, Michelle A.. University of Michigan; Estados UnidosFil: Banks, Peter A.. Brigham and Women’s Hospital. Division of Gastroenterology; Estados UnidosFil: Conwell, Darwin. Brigham and Women’s Hospital. Division of Gastroenterology; Estados UnidosFil: Lawrence, Christopher. Medical University of South Carolina; Estados UnidosFil: Romagnuolo, Joseph. Medical University of South Carolina; Estados UnidosFil: Baillie, John. University of Duke; Estados UnidosFil: Alkaade, Samer. St. Louis University. School of Medicine; Estados UnidosFil: Cote, Gregory. Indiana University; Estados UnidosFil: Gardner, Timothy B.. Dartmouth-Hitchcock Medical Center; Estados UnidosFil: Amann, Stephen T.. North Mississippi Medical Center; Estados UnidosFil: Slivka, Adam. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Sandhu, Bimaljit. Virginia Commonwealth University Medical Center; Estados UnidosFil: Aloe, Amy. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Kienholz, Michelle L.. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Yadav, Dhiraj. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Barmada, M. Michael. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Bahar, Ivet. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: Lee, Min Goo. Yonsei University College of Medicine; Corea del SurFil: Whitcomb, David C.. Univeristy of Pittsburgh. School of Medicine; Estados UnidosFil: North American Pancreatitis Study Group. No especifica

    Temporal turnover and the maintenance of diversity in ecological assemblages

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    Temporal variation in species abundances occurs in all ecological communities. Here, we explore the role that this temporal turnover plays in maintaining assemblage diversity. We investigate a three-decade time series of estuarine fishes and show that the abundances of the individual species fluctuate asynchronously around their mean levels. We then use a time-series modelling approach to examine the consequences of different patterns of turnover, by asking how the correlation between the abundance of a species in a given year and its abundance in the previous year influences the structure of the overall assemblage. Classical diversity measures that ignore species identities reveal that the observed assemblage structure will persist under all but the most extreme conditions. However, metrics that track species identities indicate a narrower set of turnover scenarios under which the predicted assemblage resembles the natural one. Our study suggests that species diversity metrics are insensitive to change and that measures that track species ranks may provide better early warning that an assemblage is being perturbed. It also highlights the need to incorporate temporal turnover in investigations of assemblage structure and function

    Establishing Foundation Archives: A Reader and Guide to First Steps

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    This publication is an anthology of papers presented at a conference held at the Rockefeller Archive Center in January 1990, and sponsored by the Council on Foundations. This collaboration of the Archive Center and the Council provided a rare opponunity for foundations to learn both why preserving documents is imponant and how several foundations have approached finding a repository or setting up and managing an archives. Participants in the conference had the added privilege of conferring with experts and seeing an operating archive as they toured the Rockefeller Archive Center.Foundations are institutions that are shaping private initiatives for the public good, so documenting this aspect of American society falls uniquely under the stewardship of the organizations themselves. Foundation documents often provide the only surviving records of the important contributions of nonprofits and foundations to civic life. These records will help to inform future judgments and ensure that the history of the field is not lost. The publication of this volume was intended to make the information shared at the conference more widely available and to provide an entry point and a primer for foundations as they begin their records and archives journey

    Double Core Evolution X. Through the Envelope Ejection Phase

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    The evolution of binary systems consisting of an asymptotic giant branch star of mass equal to 3 M_sun or 5 M_sun, and a main sequence star of mass equal to 0.4 M_sun or 0.6 M_sun with orbital periods > 200 days has been followed from the onset through the late stages of the common envelope phase. Using a nested grid technique, the three-dimensional hydrodynamical simulations of an asymptotic giant branch star with radii approximately 1 A.U. indicate that a significant fraction of the envelope gas is unbound (about 31% and 23% for binaries of 3 M_sun and 0.4 M_sun, and 5 M_sun and 0.6 M_sun respectively) by the ends of the simulations, and that the efficiency of the mass ejection process is about 40%. While the original volume of the giant is virtually evacuated in the late stages, most of the envelope gas remains marginally bound on the grid. At the ends of our simulations, when the orbital decay timescale exceeds about 5 years, the giant core and companion orbit one another with a period of about 1 day (2.4 days for a binary involving a more evolved giant), although this is an upper limit to the final orbital period. For a binary of 5 M_sun and 0.4 M_sun, the common envelope may not be completely ejected.Comment: 34 pages, 16 figures, accepted to Ap

    Chronic pancreatitis: Pediatric and adult cohorts show similarities in disease progress despite different risk factors

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    Objectives: To investigate the natural history of chronic pancreatitis (CP), patients in the North American Pancreatitis Study2 (NAPS2, adults) and INternational Study group of Pediatric Pancreatitis: In search for a cuRE (INSPPIRE, pediatric) were compared. Methods: Demographics, risk factors, disease duration, management and outcomes of 224 children and 1,063 adults were compared using appropriate statistical tests for categorical and continuous variables. Results: Alcohol was a risk in 53% of adults and 1% of children (p<0.0001); tobacco in 50% of adults and 7% of children (p<0.0001). Obstructive factors were more common in children (29% vs 19% in adults, p=0.001). Genetic risk factors were found more often in children. Exocrine pancreatic insufficiency was similar (children 26% vs adult 33%, p=0.107). Diabetes was more common in adults than children (36% vs 4% respectively, p<0.0001). Median emergency room visits, hospitalizations, and missed days of work/school were similar across the cohorts. As a secondary analysis, NAPS2 subjects with childhood onset (NAPS2-CO) were compared to INSPPIRE subjects. These two cohorts were more similar than the total INSPPIRE and NAPS2 cohorts, including for genetic risk factors. The only risk factor significantly more common in the NAPS2-CO cohort compared with the INSPPIRE cohort was alcohol (9% NAPS2-CO vs 1% INSPPIRE cohorts, p=0.011). Conclusions: Despite disparity in age of onset, children and adults with CP exhibit similarity in demographics, CP treatment, and pain. Differences between groups in radiographic findings and diabetes prevalence may be related to differences in risk factors associated with disease and length of time of CP

    An overview of population-based algorithms for multi-objective optimisation

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    In this work we present an overview of the most prominent population-based algorithms and the methodologies used to extend them to multiple objective problems. Although not exact in the mathematical sense, it has long been recognised that population-based multi-objective optimisation techniques for real-world applications are immensely valuable and versatile. These techniques are usually employed when exact optimisation methods are not easily applicable or simply when, due to sheer complexity, such techniques could potentially be very costly. Another advantage is that since a population of decision vectors is considered in each generation these algorithms are implicitly parallelisable and can generate an approximation of the entire Pareto front at each iteration. A critique of their capabilities is also provided
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