16 research outputs found

    Reliability Based Factors of Safety for VIV Fatigue Using NDP Riser High Mode VIV Tests

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    Understanding the level of conservatism in a riser system design for vortex-induced vibration (VIV) fatigue is an important issue for operators. This study represents a demonstration of the calibration methodology to derive consistent values for the Factor of Safety (FoS). The exercise is performed here based on medium scale VIV data and utilizing the most commonly used VIV prediction software by industry. The results emphasize the need for (i) a coherent approach to estimate the FoS to be used and (ii) monitoring/measurement of software improvements as this may increase risk of failure if the influence of such improvements on the FoS is not quantified.DeepStar (Consortium) (DeepStar Phase IX

    The genetic architecture of the human cerebral cortex

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    The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

    Diagnosis of cerebrospinal fluid rhinorrhea : an evidence-based review with recommendations

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    Background: Diagnostic strategies employed for cases of cerebrospinal fluid (CSF) rhinorrhea vary widely due to limited evidence-based guidance. Methods: A systematic review of the literature was performed using PubMed, EMBASE, and Cochrane databases from January 1990 through September 2014, to examine 9 diagnostic and localization modalities for CSF rhinorrhea. Benefit-harm assessments, value judgments and recommendations were made based on the available evidence. Study exclusion criteria were language other than English, pre-1990 studies, case reports, and nonrhinologic leak. All authors agreed on recommendations through an iterative process. Results: We reviewed 68 studies examining 9 practices pertinent to the diagnosis of CSF rhinorrhea, with a highest aggregate grade of evidence of C. The literature does not support the use of the ring sign, glucose testing, radionuclide cisternography (RNC), or computed tomography cisternography (CTC) for identification of CSF leak. Beta-2 transferrin is the most reliable confirmatory test for CSF leak. High-resolution CT (HRCT) is then recommended as the first-line study for localization. Magnetic resonance cisternography (MRC) should be used for CSF leak identification as a second line for each of these if beta-2 transferrin is not available or if HRCT is ambiguous. Intrathecal fluorescein (IF) may also be of benefit in certain clinical scenarios. Conclusion: Despite relatively low levels of evidence, recommendations for the diagnosis and management of CSF rhinorrhea can be made based on the current literature. Higher-level studies are needed to better determine optimal diagnostic and clinical management approaches.9 page(s

    Double Jeopardy? Age, Race, and HRQOL in Older Adults with Cancer

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    Understanding the post-treatment physical and mental function of older adults from ethnic/racial minority backgrounds with cancer is a critical step to determine the services required to serve this growing population. The double jeopardy hypothesis suggests being a minority and old could have compounding effects on health. This population-based study examined the physical and mental function of older adults by age (mean age = 75.7, SD = 6.1), ethnicity/race, and cancer (breast, prostate, colorectal, and gynecologic) as well as interaction effects between age, ethnicity/race and HRQOL. There was evidence of a significant age by ethnicity/race interaction in physical function for breast, prostate and all sites combined, but the interaction became non-significant (for breast and all sites combined) when comorbidity was entered into the model. The interaction persisted in the prostate cancer group after controlling for comorbidity, such that African Americans and Asian Americans in the 75–79 age group report lower physical health than non-Hispanic Whites and Hispanic Whites in this age group. The presence of double jeopardy in the breast and all sites combined group can be explained by a differential comorbid burden among the older (75–79) minority group, but the interaction found in prostate cancer survivors does not reflect this differential comorbid burden

    Data from: Phenotypic evolution shaped by current enzyme function in the bioluminescent courtship signals of sea fireflies

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    Mating behaviours are diverse and noteworthy, especially within species radiations where they may contribute to speciation. Studying how differences in mating behaviours arise between species can help us understand how diversity is generated at multiple biological levels. The bioluminescent courtship displays of cypridinid ostracods (or sea fireflies) are an excellent system for this since amazing variety evolves while using a conserved biochemical mechanism. We find that the evolution of one aspect in this behavioural phenotype - the duration of bioluminescent courtship pulses - is shaped by biochemical function. First, by measuring light production from induced bioluminescence in 38 species, we discovered differences between species in their biochemical reactions. Then, for 16 species of which biochemical, phylogenetic, and behavioral data are all available, we used phylogenetic comparative models to show that differences in biochemical reaction are nonlinearly correlated with the duration of courtship pulses. This relationship indicates that changes to both enzyme (c-luciferase) function and usage have shaped the evolution of courtship displays, but that they differentially contribute to these phenotypic changes. This nonlinear dynamic may have consequences for the disparity of signaling phenotypes observed across species, and demonstrates how unappreciated diversity at the biochemical level can lead to inferences about behavioural evolution

    Hepatocytes express nerve growth factor during liver injury: evidence for paracrine regulation of hepatic stellate cell apoptosis

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    A key feature of recovery from liver fibrosis is hepatic stellate cell (HSC) apoptosis, which serves the dual function of removing the major source of neomatrix and tissue inhibitors of metalloproteinases thereby facilitating matrix degradation. The mechanisms regulating HSC apoptosis remain undefined but may include the interaction of nerve growth factor (NGF) with its receptor, p75, on HSC. In this study, by TaqMan polymerase chain reaction in situ hybridization and immunohistochemistry, we demonstrate that NGF is expressed by hepatocytes during fibrotic injury. Peak hepatocyte expression of NGF (48 hours after CCl4 injection) coincides with maximal rate of apoptosis of HSC by terminal dUTP nick-end labeling staining. Addition of recombinant NGF to HSC in tissue culture causes a dose-dependent increase in apoptosis. NGF regulates nuclear factor (NF)-?B activity, reducing p50/p65 binding detected by electromobility shift assay and reduced NF-?B CAT reporter activities from both basal unstimulated levels and after NF-?B induction by tumor necrosis factor. In each case, a relative reduction in NF-?B binding was associated with a significant increase in caspase 3 activity. These data provide evidence that NGF is expressed during fibrotic liver injury and may regulate number of activated HSCs via induction of apoptosis

    Total intravenous anesthesia improves intraoperative visualization during surgery for high-grade chronic rhinosinusitis: a double-blind randomized controlled trial

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    Total intravenous anesthesia (TIVA) has been proposed as a method to reduce blood loss during endoscopic sinus surgery (ESS). Impaired sinonasal visualization due to mucosal bleeding may be burdensome in cases of chronic rhinosinusitis (CRS) with high-grade inflammatory disease, suggesting a role for TIVA in that disease subgroup.A double-blind, randomized controlled trial was conducted of adults undergoing ESS at a tertiary medical center. Patients considered for inclusion had high-grade CRS defined as either sinonasal polyposis or a preoperative Lund-Mackay score of ≥12. Subjects were randomized to receive either TIVA or inhaled anesthesia (IA) during ESS. The primary outcome measure was intraoperative visibility as rated by 3 blinded reviewers utilizing the 10-point Wormald Surgical Field Grading Scale. Secondary outcomes included operative blood loss, complications, and change in quality of life evaluated by the 22-item Sino-Nasal Outcome Test (SNOT-22).A total of 72 patients were randomized into TIVA (n = 37) and IA (n = 35) study arms. Aggregate median (interquartile range) Wormald scores across all reviewers demonstrated a more favorable visual field with TIVA compared to IA (3.5 [2.4-3.9] vs IA 4.1[3.0-5.8], p = 0.0089). There was significantly less blood loss in the TIVA group compared to the IA group (200 mL [100-450] vs 300 mL [200-500], p = 0.046). Baseline patient characteristics were comparable between cohorts with no significant postoperative complications. No significant changes were detected between postoperative SNOT-22 scores at 3 months (p = 0.278) and at 6 months (p = 0.396) following ESS.TIVA contributes to improved intraoperative visualization and decreased blood loss in patients undergoing ESS for high-grade inflammatory sinus disease
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