Filter Results
40681 results
Titanium white (TiO2) has been widely used as a pigment in the 20th century. However, its most photocatalytic form (anatase) can cause severe degradation of the oil paint in which it is contained. UV light initiates TiO2-photocatalyzed processes in the paint film, degrading the oil binder into volatile components resulting in chalking of the paint. This will eventually lead to severe changes in the appearance of a painting. To date, limited examples of degraded works of art containing titanium white are known due to the relatively short existence of the paintings in question and the slow progress of the degradation process. However, UV light will inevitably cause degradation of paint in works of art containing photocatalytic titanium white.
Data Types:
  • Slides
  • Image
  • Tabular Data
  • Document
The purpose of the study was to separate and identify the unknown surfactants present in flowback and produced water from oil and gas wells in the Denver-Julesburg Basin (Niobrara Formation) in Weld County, Colorado, USA. Weld County has been drilled extensively during the last five years for oil and gas between 7000–8000 feet below land-surface. Polypropylene glycols (PPGs) and polyethylene glycols carboxylates (PEG-Cs) were found for the first time in these flowback and produced water samples. These ethoxylated surfactants may be used as friction reducers, clay stabilizers, and surfactants. Ultrahigh-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UHPLC/QTOF-MS) was used to separate and identify the different classes of PPGs, PEG-Cs, and their isomers. The Kendrick mass scale was applied along with mass spectrometry/mass spectrometry (MS-MS) with accurate mass for rapid and unequivocal identification. The PPGs and their isomers occur at the ppm concentration range and may be useful as “fingerprints” of hydraulic-fracturing. Comparing these detections to the compounds used in the fracturing process from FracFocus 3.0 (https://fracfocus.org), it appears that both PPGs and polyethylene glycols (PEGs) are commonly named as additives, but the PEG-Cs have not been reported. The PEG-Cs may be trace impurities or degradation products of PEGs.
Data Types:
  • Slides
  • Image
  • Tabular Data
Randomized control trials (RCTs) have long been the gold standard for allowing causal inferences to be made regarding the efficacy of a treatment under investigation, but traditional RCT data analysis perspectives do not take into account a common reality: imperfect participant compliance to treatment. Recent advances in both maximum likelihood parameter estimation and mixture modeling methodology have enabled treatment effects to be estimated, in the presence of less than ideal levels of participant compliance, via a Complier Average Causal Effect (CACE) structural equation mixture model. CACE is described in contrast to “intent to treat” (ITT), “per protocol”, and “as treated” RCT data analysis perspectives. CACE model assumptions, specification, estimation, and interpretation will all be demonstrated with simulated data generated from a randomized controlled trial of cognitive-behavioral therapy for Juvenile Fibromyalgia. CACE analysis model figures, linear model equations, and Mplus estimation syntax examples are all provided.
Data Types:
  • Image
  • Tabular Data
  • Document
  • File Set
This paper focuses on a perishable product supply chain with a vendor and multiple retailers. These retailers, densely spread in a distribution zone, are sensitive to price, delivery time and product quality. With the aim of optimizing the vendor’s expected long-run average profit during a shipment consolidation cycle, an analytical model is proposed for this problem. According to the upper bound expressions of the expected long-run average profit, the approximate optimal time policy and freshness-keeping cost are given based on a certain range of time parameter. Our theoretical findings are verified through a numerical case. Some useful managerial insights are obtained by analyzing the sensitivity of this model from six perspectives, which are market scenarios, types of perishable products, quality requirements of all retailers, cost parameters, line-haul time and vehicle capacity.
Data Types:
  • Image
  • Tabular Data
  • File Set
The aim of this study is to assess the effect of switching to rotigotine transdermal patch on severity of restless legs syndrome (RLS) in patients who experienced acute augmentation with previous oral dopaminergics.
Data Types:
  • Image
  • Tabular Data
  • Document
  • File Set
We aimed to examine health-related physical fitness and its demographic and clinical correlates in patients recently treated with autologous stem cell transplantation.
Data Types:
  • Slides
  • Tabular Data
  • Document
A low-salt diet has been the main treatment modality for Ménière's disease (MD) since the 1930s, although the mechanisms behind this therapy have not yet been elucidated. Salt reduction is associated with a physiological increase in plasma aldosterone concentration. Several experimental reports have suggested that aldosterone may increase endolymph absorption in the inner ear, particularly in the endolymphatic sac. Therefore, aldosterone elevations due to a low-salt diet may increase endolymph absorption in the endolymphatic sac. In this study, urinary sodium excretion, plasma aldosterone, and other hormones were measured during low-salt diet therapy in patients with MD.
Data Types:
  • Slides
  • Image
  • Tabular Data
This study extends a neoclassical growth model to include the accumulation of physical capital and energy consumption within a panel of fifty states (plus the District of Columbia) in the U.S. The theoretical model allows us to examine the implications for convergence in economic growth and energy intensity. From the theoretical model, we formulate an empirical approach using a dynamic panel model that is estimated using a general method of moments framework to test the conditional rates of convergence. The empirical results indicate convergence in energy intensity, and our estimates accurately predict both the growth in and convergence of energy intensity across our entire sample. Consistent with other findings in the literature, our results imply that energy use, over the past four decades, plays a small and positive role in state-level, per capita economic growth and convergence. Based on these results, we discuss policy implications for state-level income growth and energy consumption.
Data Types:
  • Image
  • Tabular Data
  • File Set
In this paper, we propose a new metaheuristic to solve the Risk constrained Cash-in-Transit Vehicle Routing Problem (Rctvrp). The Rctvrp is a variant of the well-known capacitated vehicle routing problem and models the problem of routing vehicles in the cash-in-transit sector. In the Rctvrp, the risk associated with a robbery represents a critical aspect that is treated as a limiting factor subject to a maximum risk threshold.
Data Types:
  • Image
  • Tabular Data
  • File Set
miRNAs are integral for maintaining immune homeostasis and self-tolerance. The influence of miRNAs on T-cell differentiation and plasticity are critical in the development of chronic rejection of transplanted hearts. In this study, we sought to determine whether the knockout of miR-155 affects the development of cardiac allograft vasculopathy (CAV) in a murine model.
Data Types:
  • Image
  • Tabular Data
  • File Set
5