397 research outputs found
Video-based Assessments of Colonoscopy Inspection Quality Correlate with Quality Metrics and Highlight Areas for Improvement
Background & Aims
Adenoma detection rate (ADR) and serrated polyp detection rate (SDR) vary significantly among colonoscopists. Colonoscopy inspection quality (CIQ) is the quality with which a colonoscopist inspects for polyps and may explain some of this variation. We aimed to determine the relationship between CIQ and historical ADRs and SDRs in a cohort of colonoscopists and assess whether there is variation in CIQ components (fold examination, cleaning, and luminal distension) among colonoscopists with similar ADRs and SDRs.
Methods
We conducted a prospective observational study to assess CIQ among 17 high-volume colonoscopists at an academic medical center. Over 6 weeks, we video-recorded >28 colonoscopies per colonoscopist and randomly selected 7 colonoscopies per colonoscopist for evaluation. Six raters graded CIQ using an established scale, with a maximum whole colon score of 75.
Results
We evaluated 119 colonoscopies. The median whole-colon CIQ score was 50.1/75. Whole-colon CIQ score (r=0.71; P<.01) and component scores (fold examination r=0.74; cleaning r=0.67; distension r=0.77; all P<.01) correlated with ADR. Proximal colon CIQ score (r=0.67; P<.01) and component scores (fold examination r=0.71; cleaning r=0.62; distension r=0.65; all P<.05) correlated with SDR. CIQ component scores differed significantly between colonoscopists with similar ADRs and SDRs for most of the CIQ skills.
Conclusion
In a prospective observational study, we found CIQ and CIQ components to correlate with ADR and SDR. Colonoscopists with similar ADRs and SDRs differ in their performance of the 3 CIQ componentsâspecific, actionable feedback might improve colonoscopy technique
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Frenemies: how do financial firms vote on their own kind?
The financial sector is unique in being largely self-governed: the majority of financial firmsâ shares are held by other financial institutions. This raises the possibility that monitoring of financial firms is especially undermined by conflicts of interest due to personal and professional links between these firms and their shareholders. To investigate this possibility, we scrutinize the aspect of the financial sectorâs self-governance that is directly observable: mutual fund companiesâ voting of their peersâ stock. We find that considerations specific to investee firmsâ membership in the same industry as their investors do indeed impact voting. This impact is in the direction of supporting the investeeâs management. We show that the own-industry effect reduces director efficacy and lowers firm value as a result. We extend our analysis to other financial companies and show that they also tend to vote more favorably when it comes to their peers. Our results suggest that peer support is a corrupting factor in the financial sectorâs governance
Arginase Promotes Neointima Formation in Rat Injured Carotid Arteries
ObjectiveĂąâŹâArginase stimulates the proliferation of cultured vascular smooth muscle cells
(VSMCs); however, the influence of arginase on VSMC growth in vivo is not known. This study
investigated the impact of arginase on cell cycle progression and neointima formation following
experimental arterial injury.
Methods and ResultsĂąâŹâBalloon injury of rat carotid arteries resulted in a sustained increase in
arginase activity in the vessel wall and the induction of arginase I protein in both the media and
neointima of injured vessels. Furthermore, local perivascular application of the potent and selective
arginase inhibitors S-(2-boronoethyl)-L-cysteine (BEC) or NG-hydroxy-nor-L-arginine (L-OHNA)
immediately after injury markedly attenuated medial and neointimal DNA synthesis and neointima
formation. Substantial arginase I protein and arginase activity was also detected in rat cultured aortic
VSMCs. Moreover, treatment of VSMCs with BEC or L-OHNA, or knockdown of arginase I protein,
arrested cells in the G0/G1 phase of the cell cycle and induced the expression of the cyclin-dependent
protein kinase inhibitor, p21.
ConclusionĂąâŹâThis study demonstrates that arginase is essential for VSMCs to enter the cell cycle
and that arginase I contributes to the remodeling response following arterial injury. Arginase I
represents a potentially new therapeutic target for the treatment of vasculoproliferative disorders.Originally published Arteriosclerosis, Thrombosis, and Vascular Biology, Vol. 29, No. 4, Apr 200
The cyclic GMP modulators YC-1 and zaprinast reduce vessel remodeling through anti-proliferative and pro-apoptotic effects
Guanosine-specific cyclic nucleotide signaling is suggested to serve protective actions in the vasculature; however, the influence of selective pharmacologic modulation of cyclic guanosine monophosphate (GMP)-synthesizing soluble guanylate cyclase (sGC) or cyclic GMP-degrading phosphodiesterase (PDE) on vessel remodeling has not been thoroughly examined. In this study, rat carotid artery balloon injury was performed and the growth-modulating effects of the sGC stimulator YC-1 or the cGMP-dependent PDE-V inhibitor zaprinast were examined. YC-1 or zaprinast elevated vessel cyclic GMP content, reduced medial wall and neointimal cell proliferation, stimulated medial and neointimal cellular apoptosis, and markedly attenuated neointimal remodeling in comparable fashion. Interestingly, sGC inhibition by ODQ failed to noticeably alter neointimal growth, and concomitant zaprinast with YC-1 did not modify any parameter compared to individual treatments. These results provide novel in vivo evidence that YC-1 and zaprinast inhibit injury-induced vascular remodeling through anti-mitogenic and pro-apoptotic actions and may offer promising therapeutic approaches against vasoproliferative disorders. Originally published J Cardiovasc Pharmacol Ther, Vol. 14, No. 2, June 200
Direct Numerical Simulation Of Turbulent Multispecies Channel Flow With Wall Ablation
The design of solid rocket motors requires the prediction of changes induced by the ablation process occurring at the nozzle throat. The present study aims at understand-ing the effects of ablation on the turbulent boundary layer performing direct numerical simulations in a channel flow configuration. An ablation boundary condition for arbitrary chemical composition and pyrolysis scheme is developed and presented in this paper. Then, two DNS of a seven species reacting flow are performed: a) with inert walls; b) with ablated walls. Generated data are compared and analyzed looking at first order statistics. It is shown that the classical law of the wall for velocity and temperature are not appropriate to represent the numerical result. The chemical equilibrium assumption is shown to be valid in the inert case and a wall function consistent with this assumption is in fair agreement with the results. Nomenclature m Ì wall mass flux, kg · mâ2 · sâ1 rÌc carbon surface recession rate, m/s sÌk surface production rate of k, kg · mâ2 · sâ
Do mutual funds have consistency in their performance?
Using a comprehensive data set of 714 Chinese mutual funds from 2004 to 2015, the study investigates these fundsâ performance persistence by using the Capital Asset Pricing model, the Fama-French three-factor model and the Carhart Four-factor model. For persistence analysis, we categorize mutual funds into eight octiles based on their one year lagged performance and then observe their performance for the subsequent
12 months. We also apply Cross-Product Ratio technique to assess the performance
persistence in these Chinese funds. The study finds no significant evidence of persis- tence in the performance of the mutual funds. Winner (loser) funds do not continue to be winner (loser) funds in the subsequent time period. These findings suggest that future performance of funds cannot be predicted based on their past performance.info:eu-repo/semantics/publishedVersio
Complex gastroschisis: a new indication for fetal surgery?
Gastroschisis (GS) is a congenital abdominal wall defect, in which the bowel eviscerates from the abdominal cavity. It is a non-lethal isolated anomaly and its pathogenesis is hypothesized to occur as a result of two hits: primary rupture of the âphysiologicalâ umbilical hernia (congenital anomaly) followed by progressive damage of the eviscerated bowel (secondary injury). The second hit is thought to be caused by a combination of mesenteric ischemia from constriction in the abdominal wall defect and prolonged amniotic fluid exposure with resultant inflammatory damage, which eventually leads to bowel dysfunction and complications. GS can be classified as either simple or complex, with the latter being complicated by a combination of intestinal atresia, stenosis, perforation, volvulus and/or necrosis. Complex GS requires multiple neonatal surgeries and is associated with significantly greater postnatal morbidity and mortality than is simple GS. The intrauterine reduction of the eviscerated bowel before irreversible damage occurs and subsequent defect closure may diminish or potentially prevent the bowel damage and other fetal and neonatal complications associated with this condition. Serial prenatal amnioexchange has been studied in cases with GS as a potential intervention but never adopted because of its unproven benefit in terms of survival and bowel and lung function. We believe that recent advances in prenatal diagnosis and fetoscopic surgery justify reconsideration of the antenatal management of complex GS under the rubric of the criteria for fetal surgery established by the International Fetal Medicine and Surgery Society (IFMSS). Herein, we discuss how conditions for fetoscopic repair of complex GS might be favorable according to the IFMSS criteria, including an established natural history, an accurate prenatal diagnosis, absence of fully effective perinatal treatment due to prolonged need for neonatal intensive care, experimental evidence for fetoscopic repair and maternal and fetal safety of fetoscopy in expert fetal centers. Finally, we propose a research agenda that will help overcome barriers to progress and provide a pathway toward clinical implementation. © 2021 International Society of Ultrasound in Obstetrics and Gynecology
A spatially-VSL gravity model with 1-PN limit of GRT
A scalar gravity model is developed according the 'geometric conventionalist'
approach introduced by Poincare (Einstein 1921, Poincare 1905, Reichenbach
1957, Gruenbaum1973). In principle this approach allows an alternative
interpretation and formulation of General Relativity Theory (GRT), with
distinct i) physical congruence standard, and ii) gravitation dynamics
according Hamilton-Lagrange mechanics, while iii) retaining empirical
indistinguishability with GRT. In this scalar model the congruence standards
have been expressed as gravitationally modified Lorentz Transformations
(Broekaert 2002). The first type of these transformations relate quantities
observed by gravitationally 'affected' (natural geometry) and 'unaffected'
(coordinate geometry) observers and explicitly reveal a spatially variable
speed of light (VSL). The second type shunts the unaffected perspective and
relates affected observers, recovering i) the invariance of the locally
observed velocity of light, and ii) the local Minkowski metric (Broekaert
2003). In the case of a static gravitation field the model retrieves the
phenomenology implied by the Schwarzschild metric. The case with proper source
kinematics is now described by introduction of a 'sweep velocity' field w: The
model then provides a hamiltonian description for particles and photons in full
accordance with the first Post-Newtonian approximation of GRT (Weinberg 1972,
Will 1993).Comment: v1: 11 pages, GR17 conf. paper, Dublin 2004, v2: WEP issue solved,
section on acceleration transformation added, text improved, more references,
same results, v3: typos removed, footnotes, added and references updated, v4:
appendix added, improved tex
Clinical outcomes of EUS-guided drainage of debris-containing pancreatic pseudocysts: a large multicenter study
Background and study aimsâData on clinical outcomes of endoscopic drainage of debris-free pseudocysts (PDF) versus pseudocysts containing solid debris (PSD) are very limited. The aims of this study were to compare treatment outcomes between patients with PDF vs. PSD undergoing endoscopic ultrasound (EUS)-guided drainage via transmural stents. Patients and methodsâRetrospective review of 142 consecutive patients with pseudocysts who underwent EUS-guided transmural drainage (TM) from 2008 to 2014âat 15 academic centers in the United States. Main outcome measures included TM technical success, treatment outcomes (symptomatic and radiologic resolution), need for endoscopic re-intervention at follow-up, and adverse events (AEs). ResultsâTM was performed in 90 patients with PDF and 52 with PSD. Technical success: PDF 87 (96.7â%) vs. PSD 51 (98.1â%). There was no difference in the rates for endoscopic re-intervention (5.5â% in PDF vs. 11.5â% in PSD; Pâ=â0.33) or AEs (12.2â% in PDF vs. 19.2â% in PSD; Pâ=â0.33). Median long-term follow-up after stent removal was 297 days (interquartile range [IQR]: 59â-â424 days) for PDF and 326 days (IQR: 180â-â448 days) for PSD (Pâ=â0.88). There was a higher rate of short-term radiologic resolution of PDF (45; 66.2â%) vs. PSD (21; 51.2â%) (ORâ=â0.30; 95â% CI: 0.13â-â0.72; Pâ=â0.009). There was no difference in long-term symptomatic resolution (PDF: 70.4â% vs. PSD: 66.7â%; Pâ=â0.72) or radiologic resolution (PDF: 68.9â% vs. PSD: 78.6â%; Pâ=â0.72) ConclusionsâThere was no difference in need for endoscopic re-intervention, AEs or long-term treatment outcomes in patients with PDF vs. PSD undergoing EUS-guided drainage with transmural stents. Based on these results, the presence of solid debris in pancreatic fluid collections does not appear to be associated with a poorer outcome
Competing for space in an already crowded market: a mixed methods study of why an online community of practice (CoP) for alcohol harm reduction failed to generate interest amongst the group of public health professionals at which it was aimed
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