973 research outputs found
Energy conditions in f(R) gravity and Brans-Dicke theories
The equivalence between f(R) gravity and scalar-tensor theories is invoked to
study the null, strong, weak and dominant energy conditions in Brans-Dicke
theory. We consider the validity of the energy conditions in Brans-Dicke theory
by invoking the energy conditions derived from a generic f(R) theory. The
parameters involved are shown to be consistent with an accelerated expanding
universe.Comment: 9 pages, 1 figure, to appear in IJMP
Insider trading and future stock returns in firms with concentrated ownership levels
Peer reviewedPostprin
One-year prognosis of patients with normal myocardial perfusion imaging using technitium-99m sestamibi in suspected coronary artery disease: A single-center experience of 1,047 patients
Introduction: The aim of the present study was to evaluate the clinical outcome of a normal stress technetium-99m (99mTc)-Sestamibi single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with different probabilities of coronary artery disease (CAD). Material and Methods: A total of 1,047 subjects with a normal 99mTc-MIBI SPECT were followed up for one year and hard and soft cardiac events were assessed. Hard cardiac events were defined as cardiac death or non-fatal myocardial infarction (MI). Soft cardiac events included the patient's development of recurrent chest pain requiring coronary revascularization or significant stenosis in coronary arteries on angiography. Results: Overall, 1,047 patients (248 men and 799 women; mean age: 60.07 ± 12.31, range 29-92) were enrolled. Three hard cardiac events occurred in the groups; two had cardiac arrest and one non-fatal MI. As a result, the annualized hard cardiac event rate was 0.28%, the annualized cardiac mortality rate was 0.19%, and the rate of overall annualized cardiac events was 1.25%. Furthermore, there was a significant difference in cardiac events among patients with various pretest likelihoods of CAD (p value=0.04). Conclusion: Our data confirmed that patients with a normal 99mTc-Sestamibi myocardial SPECT are associated with a very low incidence of cardiovascular events. © The Author(s) 2011
OntoJob: Automated Ontology Learning from Labor Market Data
Due to the rapidly changing labor market and the consequently widening information gap between the labor market and education, there is a need for methods that can tackle, or at least ease, the construction of labor market ontologies. The current study set out to examine the viability of Ontology Learning (OL) methods for the (semi-)automated construction of labor market ontologies and / or taxonomies. The purpose of this paper is to propose an unsupervised framework, OntoJob, that can identify and extract from raw vacancy text instances, attributes, and relations, such as job titles, worker qualities, and the non-Taxonomic 'is-A' relations between those concepts, and convert those to an expressive descriptive logic. Evaluation of the extracted worker qualities from OntoJob, using a small sample of 5621 job postings representing 1048 occupations, showed an overall lexical precision of 0.36 and recall of 0.22. </p
Chemoenzymatic Hydrogen Production from Methanol through the Interplay of Metal Complexes and Biocatalysts
Microbial methylotrophic organisms can serve as great inspiration in the development of biomimetic strategies for the dehydrogenative conversion of C1 molecules under ambient conditions. In this Concept article, a concise personal perspective on the recent advancements in the field of biomimetic catalytic models for methanol and formaldehyde conversion, in the presence and absence of enzymes and co-factors, towards the formation of hydrogen under ambient conditions is given. In particular, formaldehyde dehydrogenase mimics have been introduced in stand-alone C1-interconversion networks. Recently, coupled systems with alcohol oxidase and dehydrogenase enzymes have been also developed for in situ formation and decomposition of formaldehyde and/or reduced/oxidized nicotinamide adenine dinucleotide (NADH/ NAD+). Although C1 molecules are already used in many industries for hydrogen production, these conceptual bioinspired low-temperature energy conversion processes may lead one day to more efficient energy storage systems enabling renewable and sustainable hydrogen generation for hydrogen fuel cells under ambient conditions using C1 molecules as fuels for mobile and miniaturized energy storage solutions in which harsh conditions like those in industrial plants are not applicable.Peer reviewe
Comparing efficacy of montelukast versus doxycycline in treatment of moderate acne
Background: Treatment of acne is an important issue for reducing the cosmetic and psychological burden of disease. Regarding the inflammatory effect of LT-B4 in acne lesions and action mechanism of Montelukast, this study was performed to determine the efficacy of Montelukastin acne treatment comparison with doxycycline. Materials and Methods: In a randomized clinical trial that was performed in Dermatology Clinic in a Training Tertiary Health Care Center in Tehran, Iran since January 2012 to May 2014, 52 patients with moderate acne were evaluated. The included patients were randomly assigned to receive doxycycline 100 mg/day plus 1 Clindamycin solution (Group 1) or Montelukast 5 mg daily plus 1 clindamycin solution (Group 2). The acne severity index was measured and compared between two groups at baseline (on admission), 1-month and 3 months later. Independent-Sample-T, Chi-Square, and Repeated-Measure ANOVA tests were used and were considered statistically significant at P < 0.05. Results: The mean age was 26.8 ± 7.1 in Group 1 and25 ± 4.8 in Group 2 (P = 0.1). 73 women and 26.7 4 men in Group 1 and 86.7 women, and 13.3 men in Group 2 (P = 0.01). The mean acne severity index at baseline was 18.2 ± 6.1 and 19 ± 4.2 in Montelukast and doxycycline group, respectively (P = 0.679). The mean acne severity index after 1-month was 10.5 ± 6.2 and 12.9 ± 3.3 in Montelukast and doxycycline group, respectively (P = 0). Finally, the mean acne severity index after 3 months follow-up was 8.6 ± 4.8 and 8.2 ± 1.2 in Montelukast and doxycycline group, respectively (P = 0.01). There was no significant difference between two groups regarding the amount of decrease in acne severity index across the study (P = 0.186). However, each groups showed a significant reduction in the acne severity index, separately (P = 0.001). Conclusion: It may be concluded that Montelukast is an effective and safe medication for moderate-level acne treatment. © 2015, Isfahan University of Medical Sciences(IUMS). All rights reserved
An electrochemical study of acrylate bone adhesive permeability and selectivity change during in vitro ageing: a model approach to the study of biomaterials and membrane barriers
This study assessed the solute permeability of a family of UV and moisture cured acrylates-based adhesives during in vitro ageing in pH 7.4 buffer. Acrylates have a potential role in bone fracture fixation, but their inability to allow microsolute exchange between the fractured bone surfaces may contribute to ineffective healing. Cyclic voltammetry and chronoamperometry were used to determine the diffusion coefficients for various electrochemically active probe molecules (O2, H2O2, acetaminophen, catechol, uric acid and ascorbic acid) at proprietary acrylic, urethane – acrylate and cyanoacrylate adhesives. All adhesives proved to be impermeable for up to 9 days ageing, following which a near-exponential increase in permeability resulted for all solutes. At 18 days, the diffusion coefficients were in the range of 10-5 cm2s-1 for O2 and H2O2 and 10-6 cm2s-1 for the organic solutes; no transport selectivity was seen between the latter. Adhesive joint strength showed a direct, inverse, correlation with permeability, with the more hydrophilic cyanoacrylates showing the greatest loss of strength. Adhesive permeabilisation does not appear to be compatible with the retention of bonding strength, but it serves as a new non-destructive predictor of adhesion strength change during ageing and practical use
Upregulation of circulating cancer stem cell marker, DCLK1 but not Lgr5, in chemoradiotherapy-treated colorectal cancer patients
Cancer stem cell (CSC) markers have attracted considerable attention in tumor diagnostic, prognostic, and therapeutic implications. Detection of cancer stem cells in circulating blood using cancer stem cell markers has received remarkable attention recently. In this study, we aimed to investigate the messenger RNA (mRNA) expression level of Lgr5 and DCLK1 as most proposed colorectal CSC markers in blood circulation also determine the subsequent association to patients� clinical and pathological findings. Peripheral blood mononuclear cells (PBMCs) of 58 patients with colorectal cancer at stage I�IV with 33 out of 58 patients undergoing preoperative chemoradiotherapy (CRT), as well as 58 healthy controls have been isolated and the extracted RNAs were analyzed using real-time PCR. The mRNA expression pattern of CSC markers of patients and controls was compared using ��Ct method. The expression level of Lgr5 was significantly higher in colorectal cancer (CRC) patients comparing to healthy group (4.8-fold change, p < 0.001). Also there was a significant increase in expression level of Lgr5 in patients at stages III and IV comparing to stages I and II (p = 0.031) and higher grades (p = 0.039) of CRC. The expression of DCLK1 was also elevated in patients significantly (2.7-fold change, p < 0.001) and the related expression was increased by increasing disease stage (p = 0.025). Combination of DCLK1 and Lgr5 markers was analyzed by logistic regression and proved to be a slightly better marker compared to each marker alone. Interestingly the DCLK1 expression level was significantly higher in patients undergoing preoperative CRT (p = 0.041); however, no association to neoadjuvant CRT was observed for Lgr5. Considering the over-expression of DCLK1 and Lgr5 in circulating blood of CRC patients comparing to controls, our results might emphasize on the presence of CSCs in blood of these patients which might be attributed to their clinical and pathological characteristics and may lead to apply in future clinical implications. Moreover, the higher expression level of DCLK1 in patients undergoing CRT can propose it as a more relevant candidate among CSC markers comparing to Lgr5 for CRC patients. © 2015, International Society of Oncology and BioMarkers (ISOBM)
Numerical analysis of shipping water impacting a step structure
Shipping water, the flow washing over and impacting the upper decks of ships and offshore structures, occurs frequently during their service life and often causes structural problems. For engineers to design safe floating structures subjected to shipping water it is essential to gain an in-depth understanding of its depth and flow field, and the resulting impact forces. In this work, Computational Fluid Dynamics (CFD) is applied to understand the physics of shipping water washing over a stepped platform. We find that the most accurate solutions are obtained with the turbulence closure. The hydrodynamic load generated by the shipping water is found to strongly depends on the kinematic energy of the water hitting the step. It is shown that with smaller values of the freeboard a more dynamic flow ensues, with a stronger vortex and larger velocity gradient resulting in deeper shipping water and a larger impact force
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