bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Research on the Effect of 2‐Ethylhexanol on Water Boiling Heat Transfer at Subatmospheric Pressure
Authors: Yu Lihua , Li Shuai , Ma Guoyuan , Sun Jihong
Published: August 2015

The addition of small amounts of surfactant to water can enhance boiling heat transfer substantially. In this experiment, 2‐ethylhexanol is used as the surfactant, and the critical micelle concentration (CMC) of the 2‐ethylhexanol aqueous solution is determined to be 1000 mg/L. The boiling heat transfer coefficients of the solutions in different concentrations on a horizontal copper rod surface at subatmospheric pressures (1.8 kPa to 3.3 kPa) are calculated according to the experiment results. The results indicate the following: when the concentration is 500 mg/L (lower than the CMC), the boiling heat transfer can be enhanced by up to 22%; when the concentration is 1000 mg/L (equal to the CMC), enhancement is up to about 60%; when the concentration is 2000 mg/L (two times the CMC), boiling heat transfer is diminished by about 60%. To a certain extent, this experiment will guide the enhancement of evaporator heat transfer in water vapor compression refrigeration and heat pump systems.
Cardiotoxin III Inhibits Hepatocyte Growth Factor‐Induced Epithelial‐Mesenchymal Transition and Suppresses Invasion of MDA‐MB‐231 Cells
Authors: Tsai Pei‐Chien , Fu Yaw‐Syan , Chang Long‐Sen , Lin Shinne‐Ren
Published: August 2015

The epithelial‐mesenchymal transition (EMT) is the first step required for breast cancer to initiate metastasis. In this study, hepatocyte growth factor (HGF) was used as a metastatic inducer of MDA‐MB‐231 cells. Cardiotoxin III (CTX III) inhibited HGF‐induced morphological changes and upregulation of E‐cadherin with the concomitant decrease in N‐cadherin and Vimentin protein levels, resulting in inhibition of cell migration and invasion. CTX III‐induced downregulation of transcription factors, Snail, Twist, and Slug, in MDA‐MB‐231 cells. CTX III suppressed c‐Met phosphorylation and downstream activation of phosphatidylinositol 3‐kinase (PI3K)/Akt and extracellular signal‐regulated kinase (ERK)1/2. The c‐Met specific inhibitor PHA665752 attenuated ERK1/2 and Akt phosphorylation, cell migration and invasion, as well as the expressional changes of EMT markers induced by HGF. Taken together, our data suggest that CTX III suppresses HGF/c‐Met‐induced cell migration and invasion by reversing EMT, which involves the inactivation of the HGF/c‐Met‐mediated ERK1/2 and PI3K/Akt pathways in MDA‐MB‐231 cells.
Binding affinities by alchemical perturbation using QM/MM with a large QM system and polarizable MM model
Authors: Genheden Samuel , Ryde Ulf , Söderhjelm Pär
Published: August 2015

The most general way to improve the accuracy of binding‐affinity calculations for protein–ligand systems is to use quantum‐mechanical (QM) methods together with rigorous alchemical‐perturbation (AP) methods. We explore this approach by calculating the relative binding free energy of two synthetic disaccharides binding to galectin‐3 at a reasonably high QM level (dispersion‐corrected density functional theory with a triple‐zeta basis set) and with a sufficiently large QM system to include all short‐range interactions with the ligand (744–748 atoms). The rest of the protein is treated as a collection of atomic multipoles (up to quadrupoles) and polarizabilities. Several methods for evaluating the binding free energy from the 3600 QM calculations are investigated in terms of stability and accuracy. In particular, methods using QM calculations only at the endpoints of the transformation are compared with the recently proposed non‐Boltzmann Bennett acceptance ratio (NBB) method that uses QM calculations at several stages of the transformation. Unfortunately, none of the rigorous approaches give sufficient statistical precision. However, a novel approximate method, involving the direct use of QM energies in the Bennett acceptance ratio method, gives similar results as NBB but with better precision, ∼3 kJ/mol. The statistical error can be further reduced by performing a greater number of QM calculations. © 2015 Wiley Periodicals, Inc.
In vitro sliding‐driven morphological changes in representative esthetic NiTi archwire surfaces
Authors: Choi Samjin , Park Dong‐Jin , Kim Kyung‐A , Park Ki‐Ho , Park Hun‐Kuk , Park Young‐Guk
Published: August 2015

Objectives

This study investigated the effects of sliding on the ultrastructure of three representative esthetic superelastic 0.014 inch nickel‐titanium (NiTi) archwires. Methods: Atomic force microscopy, scanning electron microscopy, and light microscopy were used to estimate the surface roughness of archwires and bracket systems. Energy‐dispersive X‐ray spectroscopy was used to estimate the molecular differences between coated and uncoated areas. A combination of four different types of 0.014 inch metallic wires and two different types of 0.022 inch × 0.028 inch conventional brackets were evaluated by in vitro sliding tests using a novel self‐made tensile‐strength tester with a miniature load cell and syringe pump. The NiTi wires included an uncoated NiTi archwire (CO group), epoxy resin‐coated NiTi archwire (ER group), Teflon®‐coated NiTi archwire (TF group), and Ag/biopolymer‐coated NiTi archwire (AG group). The brackets included contained stainless steel (SS) and ceramic (CE) brackets. Results: Both ER and TF wire groups exhibited less surface roughness than CO wire groups. The AG group showed the highest surface roughness compared with the others because of its silver particles (P<0.001, ANOVA test). In vitro sliding tests led to a significant increase (P < 0.001, ANOVA test) in the surface roughness of all 0.014 inch NiTi wires regardless of bracket type. The wire groups combined with SS brackets were rougher than those of CE brackets regardless of the coating materials because of exfoliation of the coating materials. The TF‐SS group showed the highest increase (fivefold) in surface roughness compared to the others, while the ER groups showed the lowest increase (1.4‐fold) in surface roughness compared with the others (P < 0.001, ANOVA test). Conclusions: The results suggested that the sliding‐driven surface roughness of superelastic NiTi archwires is directly affected by coating materials. Although the efficiency of orthodontic treatment was affected by various factors, epoxy resin‐coated archwires were best for both esthetics and tooth movement when only considering surface roughness. Microsc. Res. Tech. 78:926–934, 2015. © 2015 Wiley Periodicals, Inc.
Increasing microscopy resolution with photobleaching and intensity cumulant analysis
Authors: Brutkowski Wojtek , Dziob Daniel , Bernas Tytus
Published: August 2015

Super‐resolution fluorescence microscopy and its applications for analysis of biological structures are evolving rapidly field. A number of approaches aimed at overcoming the fundamental limit imposed by diffraction have been proposed in recent years. Here we present a modification of super‐resolution optical fluctuation imaging (SOFI), a technique based on spatio‐temporal evaluation of the optical signal from independently fluctuating emitters. Instead of rapid, reversible photoswitching, photobleaching is used to produce irreversible transitions between emitting and nonemitting states of the fluorochrome molecules. Simulated images are used to demonstrate that, in the absence of noise, the proposed SOFI modification increases the efficiency of transfer of high spatial frequencies in a fluorescence microscope. Correspondingly, a decrease of the point spread function (PSF) width is obtained. Moreover, the modified SOFI algorithm is capable of resolving point emitters in the presence of simulated noise. Using real biological images we demonstrate that an increase of resolution is obtained in 2D optical sections through densely packed chromatin in cell nuclei and lamin layer at the nuclear envelope. Finally, the approach is extended to 3D wide‐field microscopy, allowing reduction of out‐of‐focus image blurring. Microsc. Res. Tech. 78:958–968, 2015. © 2015 Wiley Periodicals, Inc.
Effect of in‐office bleaching with 35% hydrogen peroxide with and without addition of calcium on the enamel surface
Authors: Quintela Souza de Moraes Izadora , Nunes de Brito Silva Lucas , Celerino de Moraes Porto Isabel Cristina , de Lima Neto Cantídio Francisco , Barbosa Dos Santos Natanael , Silveira de Mendonça Fragoso Larissa
Published: August 2015

This study aimed to evaluate effectiveness and effects of bleaching with 35% hydrogen peroxide with and without calcium on color, micromorphology, and the replacement of calcium and phosphate on the enamel surface. Thirty bovine enamel blocks (5.0 × 5.0 mm) were placed into the following groups: G1: artificial saliva (control); G2: 35% hydrogen peroxide gel without calcium (Whiteness HP Maxx–FGM); and G3: 35% hydrogen peroxide gel with calcium (Whiteness HP Blue–FGM). Three color measurements were performed with a spectrophotometer: untreated (baseline), after performing staining, and after application of bleaching agents. Calcium deposition on the enamel was evaluated before and after the application of bleaching agents using energy‐dispersive X‐ray spectrometry. The enamel surface micromorphology was observed under scanning electron microscopy. The pH of each product was measured. The data were subjected to one‐factor analysis of variance (ANOVA), and any differences were analyzed using Tukey's test (P < 0.05). G3 showed greater variation in total color after the experiment than G2 and G1; there was no significant difference in calcium or phosphorus concentration before and after the experimental procedures; morphological changes were observed only in G2 and G3; and the pH values of the Whiteness HP Maxx and Whiteness HP Blue bleaching agents were 5.77 and 7.79, respectively. The 35% hydrogen peroxide with calcium showed greater bleaching potential, but the addition of calcium had no effect in terms of reducing morphological changes or increasing the calcium concentration on the enamel surface. Microsc. Res. Tech. 78:975–981, 2015. © 2015 Wiley Periodicals, Inc.
Polymorphisms at IL28B gene as predictors of viral relapse in genotype 4 Egyptian hepatitis C patients
Authors: Esmail Mona Abdelmonem , Hassuna Noha A. , Amr Khalda Sayed , Ghazawy Eman Ramadan , Abdel‐Hamid Mohamed
Published: August 2015

Chronic HCV is one of the commonest causes of chronic liver disease worldwide with about 15% of population infected in Egypt. Certain single nucleotide polymorphisms (SNPs) lying near the IL28B gene were found to affect the spontaneous clearance as well as treatment outcome of HCV. To examine the association between different IL28B variants and the relapse of HCV infection after combined therapy with ribavirin and pegylated interferon (pegIFN). Hundered HCV genotype four patients received 1.5 mg/kg/week peginterferon alfa‐2b plus 800–1400 mg/d ribavirin (weight‐adjusted) for 48 weeks. IL28B polymorphisms (rs12980275, rs12979860, and 1 rs8099917) were studied in responders and relapsers at week 72. Out of 69 patients receiving treatment, 13 (18.8%) were relapsers. By stratifying patients on the basis of the IL‐28/60 genotype (CC vs. CT/TT), CC patients showed lower relapse rates (2.3%) compared with CT/TT patients (46.2%) (P < 0.001). On the basis of the IL‐28/75 genotype (GG vs. GA/AA), the GG patients achieved higher relapse rates (62.5%) compared with GA/AA patients (13.1%) (P = 0.004). Moreover, no statistical significant difference was observed between the TT patients compared with GG/GT patients on the basis of the IL‐28/17 genotype. SNPs at IL‐28/60 and IL‐28/75 are possible predictors of relapse in patients receiving dual treatment. J. Med. Virol. 88:481–486, 2016. © 2015 Wiley Periodicals, Inc.
Contribution and limits of a non‐intrusive Raman spectroscopic method compared with HPLC for routine application to pre‐delivery analytical control of two major camptothecin analogs: irinotecan and topotecan
Authors: Amin Alexandre , Bourget Philippe , Ader Flavie , Vidal Fabrice , Neuzillet Cindy , Baillet‐Guffroy Arlette
Published: August 2015

The purpose of this study was to develop a Raman spectroscopy (RS) method as an effective tool for the non‐intrusive pre‐delivery analytical quality control (AQC) of two camptothecin analogs, i.e. irinotecan (IRI) and topotecan (TPT), which are prescribed and compounded at the hospital. Following a phase of analytical pre‐validation, based on the actual conditions of use of the analogs, the protocol was validated and compared with the reference high‐performance liquid chromatography (HPLC) method. For IRI, AQC by RS has been validated in ranges from 0.94 to 3.27 mg/ml in saline solutions and from 0.89 to 3.30 mg/ml in dextrose solutions. These ranges recover the entire therapeutic concentrations encountered in clinical practice, i.e. 1.08–2.8 mg/ml. The RS and HPLC methods were validated by calculating the accuracy profile and provided excellent results for the analytical validation key criteria. The Spearman and Kendall correlation tests (p‐value < 1.10−11) and the statistical studies performed on the Bland and Altman graphs confirm a strong correlation between RS and HPLC results. However, we show that a routine apparatus is unable to quantify TPT therapeutic concentrations ranging between 25 and 50 µg/ml but that a sufficiently powerful RS bench is able to detect and quantify TPT. Overall, these results confirm the potential of the RS option for future innovative applications. Owing to its analytical and practical qualities, this promising method contributes to the improvement of the safety of the medication circuit at the hospital and to the protection of caregivers and their working environment. Copyright © 2015 John Wiley & Sons, Ltd.
Raman fingerprint of chromate, aluminate and ferrite spinels
Authors: D'Ippolito Veronica , Andreozzi Giovanni B. , Bersani Danilo , Lottici Pier Paolo
Published: August 2015

Synthetic and natural spinel single crystals having compositions closely approaching spinel end‐members ZnCr2O4, MgCr2O4, FeCr2O4, ZnAl2O4, MgAl2O4, CoAl2O4, FeAl2O4, MnAl2O4, MgFe2O4, and FeFe2O4 were investigated by Raman spectroscopy in the 100–900 cm−1 range using both the red 632.8 nm line of a He‐Ne laser and the blue 473.1 nm line of a solid‐state Nd : YAG laser. Each end‐member exhibits a Raman fingerprint with at least one peculiar peak in terms of Raman shift and relative intensity. Chromates and ferrites exhibit the most intense A1g mode at around 680 cm−1, at lower wavenumbers than in the aluminates, in agreement with the heavier atomic mass of Cr and Fe with respect to Al. For aluminate spinels, the most intense and diagnostic peaks in the spectrum are as follows: F2g(1) at 202 cm−1 for MnAl2O4, Eg at 408 cm−1 for MgAl2O4, F2g(2) at 516 cm−1 for CoAl2O4, F2g(3) at 661 cm−1 for ZnAl2O4, and A1g at 748 cm−1 for FeAl2O4. Noteworthy, analyzing the A1g, F2g(3), and, in particular, the Eg peak positions, it is possible to establish which subgroup a spinel belongs to; moreover, a careful inspection of both position and relative intensity of the same peaks allows the determination of the end‐member type. Copyright © 2015 John Wiley & Sons, Ltd.
Visual rhythm for particle analysis in sample‐in‐flow systems: Application for continuous plankton monitoring
Authors: Matuszewski Damian J. , Cesar Roberto M. , Strickler J. Rudi , Baldasso Luis F. , Lopes Rubens M.
Published: August 2015

Planktonic organisms are important components of aquatic ecosystems and there is a growing interest in their exploitation for industrial purposes, such as in biofuel production using microalgae as a biomass source. The evaluation of plankton composition and abundance usually relies on time‐consuming microscopic analysis. However, automatic imaging systems are becoming increasingly available to perform such tasks. Here we present a novel method based on the visual rhythm (VR) approach to detect particles in fluidic systems through imaging techniques. It was tested on large datasets of plankton images and its performance was compared to a traditional frame‐by‐frame (FBF) approach. Performed tests demonstrated that the VR‐based approach is faster and much more precise for plankton detection and segmentation (accuracy above 96% and precision above 95%), while having the same accuracy as the FBF method. Although designed for continuous monitoring of plankton samples, the method can be easily adapted to different applications in which targets to be detected and identified move in a unidirectional flow.
Mass spectrometry in the pharmacokinetic studies of anticancer natural products
Authors: Crotti Sara , Posocco Bianca , Marangon Elena , Nitti Donato , Toffoli Giuseppe , Agostini Marco
Published: August 2015

In the history of medicine, nature has represented the main source of medical products. Indeed, the therapeutic use of plants certainly goes back to the Sumerian and Hippocrates and nowadays nature still represents the major source for new drugs discovery. Moreover, in the cancer treatment, drugs are either natural compounds or have been developed from naturally occurring parent compounds firstly isolated from plants and microbes from terrestrial and marine environment. A critical element of an anticancer drug is represented by its severe toxicities and, after administration, the drug concentrations have to remain in an appropriate range to be effective. Anyway, the drug dosage defined during the clinical studies could be inappropriate for an individual patient due to differences in drug absorption, metabolism and excretion. For this reason, personalized medicine, based on therapeutic drug monitoring (TDM), represents one of most important challenges in cancer therapy. Mass spectrometry sensitivity, specificity and fastness lead to elect this technique as the Golden Standard for pharmacokinetics and drug metabolism studies therefore for TDM. This review focuses on the mass spectrometry‐based methods developed for pharmacokinetic quantification in human plasma of anticancer drugs derived from natural sources and already used in clinical practice. Particular emphasis was placed both on the pre‐analytical and analytical steps, such as: sample preparation procedures, sample size required by the analysis and the limit of quantification of drugs and metabolites to give some insights on the clinical practice applicability. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:213–251, 2017
Conceptualizing a Research Paradigm for Multi‐Objective Modelling in Supply Chain Management
Authors: Oral Muhittin , Kettani Ossama
Published: August 2015

The primary objective of this paper is to offer a particular research paradigm framework that takes into consideration ontological, epistemological, methodological and axiological assumptions for a more meaningful and comprehensive research activities while using multi‐objective modelling approach in supply chain management (SCM) studies. However, the emphasis will be more on the implications of four ontological level definitions for multi‐objective modelling in SCM research through a concept called ‘inclusiveness’. Such a particular research paradigm framework helps SCM researchers broaden their research problem definitions and enhance their multi‐objective modelling process. Copyright © 2015 John Wiley & Sons, Ltd.
Heuristic Based Real‐Time Train Rescheduling System
Authors: Mladenovic Snezana , Veskovic Slavko , Branovic Irina , Jankovic Sladjana , Acimovic Slavisa
Published: August 2015

This article deals with the problem of train rescheduling on a railway network. Starting from a defined network topology and initial timetable, the article considers a dynamic train rescheduling in response to disturbances that have occurred. The train rescheduling problem was mapped into a special case of the job shop scheduling problem and solved by applying a constraint programming approach. To improve the time performance of available constraint programming tool and to satisfy a selected objective function, a combination of three classes of heuristics are proposed: bound heuristics, separation heuristics, and search heuristics. Experimental evaluation of the implemented software in Belgrade railway dispatching area indicates that the proposed approach is capable of providing the support to a real‐life operational railway control. In our solution, the dispatcher has the possibility of choosing the most suitable optimization criterion from the set of seven available ones. © 2015 Wiley Periodicals, Inc. NETWORKS, Vol. 67(1), 32–48 2016
Dynamic vehicle routing problems: Three decades and counting
Authors: Psaraftis Harilaos N. , Wen Min , Kontovas Christos A.
Published: August 2015

Since the late 70s, much research activity has taken place on the class of dynamic vehicle routing problems (DVRP), with the time period after year 2000 witnessing a real explosion in related papers. Our paper sheds more light into work in this area over more than 3 decades by developing a taxonomy of DVRP papers according to 11 criteria. These are (1) type of problem, (2) logistical context, (3) transportation mode, (4) objective function, (5) fleet size, (6) time constraints, (7) vehicle capacity constraints, (8) the ability to reject customers, (9) the nature of the dynamic element, (10) the nature of the stochasticity (if any), and (11) the solution method. We comment on technological vis‐à‐vis methodological advances for this class of problems and suggest directions for further research. The latter include alternative objective functions, vehicle speed as decision variable, more explicit linkages of methodology to technological advances and analysis of worst case or average case performance of heuristics. © 2015 Wiley Periodicals, Inc. NETWORKS, Vol. 67(1), 3–31 2016
Effects of in‐situ functionalization of carbon nanotubes with bis(triethoxysilylpropyl) tetrasulfide (TESPT) and 3‐aminopropyltriethoxysilane (APTES) on properties of epoxidized natural rubber–carbon nanotube composites
Authors: Nakaramontri Yeampon , Nakason Charoen , Kummerlöwe Claudia , Vennemann Norbert
Published: August 2015

Composites of carbon nanotubes (CNT) and epoxidized natural rubber (ENR) were prepared by in‐situ functionalization of CNT with two alternative silane coupling agents: bis(triethoxysilylpropyl) tetrasulfide (TESPT) and 3‐aminopropyltriethoxysilane (APTES). The reactions of ENR molecules with the functional groups on CNT surfaces and with the silane molecules were characterized by Fourier transform infrared. Furthermore, cross‐link density, relaxation behaviors, curing, mechanical, electrical, and morphological properties of pristine ENR and the ENR composites were investigated. Very low percolation thresholds, at CNT concentrations as low as 1 phr, were observed in the ENR–CNT and the ENR–CNT–TESPT composites. This might be attributed to improvements in the chemical linkages between ENR molecules and functional groups on CNT surfaces that led to a homogenous dispersion of CNTs in the ENR matrix, with loose CNT agglomerates. POLYM. ENG. SCI., 55:2500–2510, 2015. © 2015 Society of Plastics Engineers
Effect of solvent additives on bulk heterojunction morphology of organic photovoltaics and their impact on device performance
Authors: Choi Won Tae , Song Jiyun , Ko Jongkuk , Jang Yeongseon , Kim Tae‐Hwan , Han Young‐Soo , Lim Jeewoo , Lee Changhee , Char Kookheon
Published: August 2015

Morphology of the active layer in an organic photovoltaic (OPV) device is known to have a significant impact on the device performance. It is, however, difficult to characterize nanoscale morphologies in detail, especially at the ensemble level. Herein, we report the utilization of small angle neutron scattering (SANS) to investigate variations in the nanoscale morphologies of the active layer of poly(3‐hexylthiophene‐2,5‐diyl):[6,6]‐phenyl‐C61‐butyric acid methyl ester (P3HT:PCBM) bulk heterojunction OPV depending on the composition of casting solvent. Both the power law and the poly hard sphere model were utilized to characterize the state of the donor and acceptor components, respectively, from the obtained SANS data. Furthermore, the relationship between the nanoscale morphology and device performance is outlined. It was found that the use of 2‐chlorophenol, a poor solvent for P3HT and, at the same time, a very good solvent for PCBM, leads to nanomorphology featuring ordered, highly crystalline P3HT and small (15.2 nm) PCBM domains. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 128–134
Influence of sintering temperature on microstructures and energy‐storage properties of barium strontium titanate glass‐ceramics prepared by sol–gel process
Authors: Zhu Jia , Zhang Yong , Song Xiaozhen , Zhang Qian , Yang Dongliang , Chen Yongzhou
Published: August 2015

The sol–gel processing, microstructures, dielectric properties and energy‐storage properties of barium strontium titanate glass‐ceramics over the sintering temperature range of 1000–1150 °C were studied. Through the X‐ray diffraction result, it is revealed that the crystallinity increases as the sintering temperature increased from 1000 to 1080 °C and has reached a steady‐state regime above 1100 °C. Scanning electron microscopy images showed that with the increase of sintering temperature, the crystal size increased. Dielectric measurements revealed that the increase in the sintering temperature resulted in a significant increase in the dielectric constant, a strong sharpness of the temperature‐dependent dielectric response and a pronounced decrease of the temperature of the dielectric maximum. The correlation between charge spreading behavior and activation energies of crystal and glass was discussed by the employment of the impedance spectroscopy studies. As a result of polarization‐electric field hysteresis loops, both the charged and discharged densities increased with increasing sintering temperature. And the maximum value of energy storage efficiency was found to occur at 1130 °C. Finally, the dependence of released energy and power densities calculated from the discharged current–time (I–t) curves on the sintering temperature was studied. The relationship between the energy storage properties and microstructure was correlated.

Polarization–electric field hysteresis loops for the BST glass‐ceramics sintered at different temperatures.
The evolution of the ECMWF hybrid data assimilation system
Authors: Bonavita Massimo , Hólm Elias , Isaksen Lars , Fisher Mike
Published: August 2015

The trend towards using flow‐dependent, ensemble‐based estimates of background‐error covariances has been one of the main themes of atmospheric data assimilation research and development in recent years. In this work it is documented how flow‐dependent ensemble information from the ECMWF ensemble of data assimilations (EDA) has gradually been incorporated into the B model which describes the background‐error covariance matrix at the start of the ECMWF 4D‐Var assimilation window. Starting with background‐error variances for the balanced part of the control vector and observation quality control, the current article extends the flow‐dependency to background‐error variances for the unbalanced part of the control vector and for background‐error correlation structures. The correlations are determined either online from previous days or from a hybrid of climatological and current cycle estimates. Each of these changes is shown to improve both the realism of the modelled B and the accuracy of the analysis and forecast fields produced by the 4D‐Var assimilation cycle which makes use of the improved B. Finally, increasing the resolution at which the EDA 4D‐Vars are run is shown to reduce the underestimation of the EDA‐based error estimates.
On the evaluation of reputation and trust‐based schemes in mobile ad hoc networks
Authors: Abbas Sohail , Merabti Madjid , Llewellyn‐Jones David
Published: August 2015

In multihop networks such as mobile ad hoc networks selfish or misbehaving nodes can degrade network performance. Reputation and trust‐based schemes have been proposed in order to enforce cooperation and to discourage misbehaving nodes. These schemes detect and isolate selfish nodes and maintain network throughput by enabling nodes to construct paths that only include good nodes. In order to punish selfish nodes and restrict their services, selfish nodes are not provided with packet forwarding services anymore by the good nodes in the network. The aim of these schemes is to increase good nodes' benefit (throughput and utility) and to decrease malicious nodes' benefit. In this paper, we demonstrate that the commonly adopted simulation parameters used by the research community for the evaluation of reputation or trust‐based schemes in mobile environments usually produce biased results. We further demonstrate this fact by adopting a widely used reputation‐based scheme as our case study using the commonly used metrics, such as throughput, utility, delay, and overhead. The simulation parameters are analyzed analytically and via simulations in order to demonstrate their main reason of producing inaccurate and biased results. Finally, we compare simulation and analytical results to corroborate our claim and discuss how to mitigate the resulted inaccuracy and biasness. Copyright © 2015 John Wiley & Sons, Ltd.
A nonparametric fiducial interval for the Youden index in multi‐state diagnostic settings
Authors: Batterton Katherine A. , Schubert Christine M.
Published: August 2015

The Youden index is a commonly employed metric to characterize the performance of a diagnostic test at its optimal point. For tests with three or more outcome classes, the Youden index has been extended; however, there are limited methods to compute a confidence interval (CI) about its value. Often, outcome classes are assumed to be normally distributed, which facilitates computational formulas for the CI bounds; however, many scenarios exist for which these assumptions cannot be made. In addition, many of these existing CI methods do not work well for small sample sizes. We propose a method to compute a nonparametric interval about the Youden index utilizing the fiducial argument. This fiducial interval ensures that CI coverage is met regardless of sample size, underlying distributional assumptions, or use of a complex classifier for diagnosis. Two alternate fiducial intervals are also considered. A simulation was conducted, which demonstrates the coverage and interval length for the proposed methods. Comparisons were made using no distributional assumptions on the outcome classes and for when outcomes were assumed to be normally distributed. In general, coverage probability was consistently met, and interval length was reasonable. The proposed fiducial method was also demonstrated in data examining biomarkers in subjects to predict diagnostic stages ranging from normal kidney function to chronic allograph nephropathy. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
Hierarchical likelihood inference on clustered competing risks data
Authors: Christian Nicholas J. , Ha Il Do , Jeong Jong‐Hyeon
Published: August 2015

The frailty model, an extension of the proportional hazards model, is often used to model clustered survival data. However, some extension of the ordinary frailty model is required when there exist competing risks within a cluster. Under competing risks, the underlying processes affecting the events of interest and competing events could be different but correlated. In this paper, the hierarchical likelihood method is proposed to infer the cause‐specific hazard frailty model for clustered competing risks data. The hierarchical likelihood incorporates fixed effects as well as random effects into an extended likelihood function, so that the method does not require intensive numerical methods to find the marginal distribution. Simulation studies are performed to assess the behavior of the estimators for the regression coefficients and the correlation structure among the bivariate frailty distribution for competing events. The proposed method is illustrated with a breast cancer dataset. Copyright © 2015 John Wiley & Sons, Ltd.
Prospective evaluation of the fetal heart using Fetal Intelligent Navigation Echocardiography (FINE)
Authors: Garcia M. , Yeo L. , Romero R. , Haggerty D. , Giardina I. , Hassan S. S. , Chaiworapongsa T. , Hernandez‐Andrade E.
Published: August 2015

Objective

To evaluate prospectively the performance of Fetal Intelligent Navigation Echocardiography (FINE) applied to spatiotemporal image correlation (STIC) volume datasets of the normal fetal heart.

Methods

In all women between 19 and 30 weeks' gestation with a normal fetal heart, an attempt was made to acquire STIC volume datasets of the apical four‐chamber view if the following criteria were met: (1) fetal spine located between 5‐ and 7‐o'clock positions; (2) minimal or absent shadowing (including a clearly visible transverse aortic arch); (3) absence of fetal breathing, hiccups, or movement; and (4) adequate image quality. Each STIC volume successfully acquired was evaluated by STICLoop™ to determine its appropriateness before applying the FINE method. Visualization rates of fetal echocardiography views using diagnostic planes and/or Virtual Intelligent Sonographer Assistance (VIS‐Assistance®) were calculated.

Results

One or more STIC volumes (365 in total) were obtained successfully in 72.5% (150/207) of women undergoing ultrasound examination. Of the 365 volumes evaluated by STICLoop, 351 (96.2%) were considered to be appropriate. From the 351 STIC volumes, only one STIC volume per patient (n = 150) was analyzed using the FINE method, and consequently nine fetal echocardiography views were generated in 76–100% of cases using diagnostic planes only, in 98–100% of cases using VIS‐Assistance only, and in 98–100% of cases when using a combination of diagnostic planes and/or VIS‐Assistance.

Conclusions

In women between 19 and 30 weeks' gestation with a normal fetal heart undergoing prospective sonographic examination, STIC volumes can be obtained successfully in 72.5% of cases. The FINE method can be applied to generate nine standard fetal echocardiography views in 98–100% of these cases using a combination of diagnostic planes and/or VIS‐Assistance. This suggests that FINE could be implemented in fetal cardiac screening programs. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
Emerging challenges for pathogen control and resource recovery in natural wastewater treatment systems
Authors: Verbyla Matthew E. , Cairns Maryann R. , Gonzalez Paola A. , Whiteford Linda M. , Mihelcic James R.
Published: August 2015

Natural wastewater treatment systems have been used for centuries to recover resources through agriculture and aquaculture water reuse. Because the management of wastewater using natural methods relies on the integration of environmental, engineered, economic, and social systems, pathogens cannot be effectively monitored and controlled in these systems using a single approach or a single indicator organism (e.g., monitoring for coliform indicator bacteria). Different types of pathogens are removed at different rates in natural wastewater treatment systems and certain diseases are more important in some regions than they are in others. For natural systems in tropical regions that incorporate water reuse for agriculture or aquaculture, parasites such as soil‐transmitted helminths, Schistosoma, Taenia, or food‐transmitted trematodes may be of greater public health concern than some bacterial pathogens. Professionals and practitioners must consider how social and environmental systems might be shaped by the use of natural wastewater management systems, and how, in turn, natural wastewater management may impact existing socio‐environmental relationships. Because of this, effective pathogen monitoring and control in natural wastewater treatment systems requires coordinated participation from stakeholders in multiple sectors. WIREs Water 2015, 2:701–714. doi: 10.1002/wat2.1101

This article is categorized under:

Engineering Water > Water, Health, and Sanitation
“Unfocus” on foc.us: commercial tDCS headset impairs working memory
Authors: Steenbergen Laura , Sellaro Roberta , Hommel Bernhard , Lindenberger Ulman , Kühn Simone , Colzato Lorenza S.
Published: August 2015

In this study, we tested whether the commercial transcranial direct current stimulation (tDCS) headset foc.us improves cognitive performance, as advertised in the media. A single-blind, sham-controlled, within-subject design was used to assess the effect of online and off-line foc.us tDCS—applied over the prefrontal cortex in healthy young volunteers (n = 24) on working memory (WM) updating and monitoring. WM updating and monitoring, as assessed by means of the N-back task, is a cognitive-control process that has been shown to benefit from interventions with CE-certified tDCS devices. For both online and off-line stimulation protocols, results showed that active stimulation with foc.us, compared to sham stimulation, significantly decreased accuracy performance in a well-established task tapping WM updating and monitoring. These results provide evidence for the important role of the scientific community in validating and testing far-reaching claims made by the brain training industry.
U.S. Border Enforcement and Mexican Immigrant Location Choice
Authors: Bohn Sarah , Pugatch Todd
Published: August 2015

We provide the first evidence on the causal effect of border enforcement on the full spatial distribution of Mexican immigrants to the United States. We address the endogeneity of border enforcement with an instrumental variables strategy based on administrative delays in budgetary allocations for border security. We find that 1,000 additional Border Patrol officers assigned to prevent unauthorized migrants from entering a U.S. state decreases that state’s share of Mexican immigrants by 21.9 %. Our estimates imply that if border enforcement had not changed from 1994 to 2011, the shares of Mexican immigrants locating in California and Texas would each be 8 percentage points greater, with all other states’ shares lower or unchanged.
The Successful Saga of a Cesarean Scar Ectopic with High βHCG Level
Authors: Rohatgi Tanya B. , Buckshee Kamal , Sahni Reeti
Published: August 2015

Cesarean scar ectopic (CSE) is a rare life-threatening condition associated with hemorrhage, uterine rupture, disseminated intravascular coagulation or death during pregnancy. A rampant increase is worrisome. Early diagnosis is critical; awareness and high index of suspicion are essential. We report a 34-year-old woman with two previous cesarean sections, who was diagnosed to have an unruptured, viable CSE with high βHCG level (49,637. 08 mIU/mL). Local as well as systemic methotrexate failed initially. However, success was achieved when modified medical treatment was adopted.
A Pilot Study of a Computerized Decision Support System to Detect Invasive Fungal Infection in Pediatric Hematology/Oncology Patients
Authors: Bartlett Adam , Goeman Emma , Vedi Aditi , Mostaghim Mona , Trahair Toby , O’Brien Tracey A. , Palasanthiran Pamela , McMullan Brendan
Published: August 2015

OBJECTIVE

Computerized decision support systems (CDSSs) can provide indication-specific antimicrobial recommendations and approvals as part of hospital antimicrobial stewardship (AMS) programs. The aim of this study was to assess the performance of a CDSS for surveillance of invasive fungal infections (IFIs) in an inpatient hematology/oncology cohort.

METHODS

Between November 1, 2012, and October 31, 2013, pediatric hematology/oncology inpatients diagnosed with an IFI were identified through an audit of the CDSS and confirmed by medical record review. The results were compared to hospital diagnostic-related group (DRG) coding for IFI throughout the same period.

RESULTS

A total of 83 patients were prescribed systemic antifungals according to the CDSS for the 12-month period. The CDSS correctly identified 19 patients with IFI on medical record review, compared with 10 patients identified by DRG coding, of whom 9 were confirmed to have IFI on medical record review.

CONCLUSIONS

CDSS was superior to diagnostic coding in detecting IFI in an inpatient pediatric hematology/oncology cohort. The functionality of CDSS lends itself to inpatient infectious diseases surveillance but depends on prescriber adherence.

Infect. Control Hosp. Epidemiol. 2015;36(11):1313–1317
The Effect of Contact Precautions on Frequency of Hospital Adverse Events
Authors: Croft Lindsay D. , Liquori Michael , Ladd James , Day Hannah , Pineles Lisa , Lamos Elizabeth , Arnold Ryan , Mehrotra Preeti , Fink Jeffrey C. , Langenberg Patricia , Simoni-Wastila Linda , Perencevich Eli , Harris Anthony D. , Morgan Daniel J.
Published: August 2015

OBJECTIVE

To determine whether use of contact precautions on hospital ward patients is associated with patient adverse events

DESIGN

Individually matched prospective cohort study

SETTING

The University of Maryland Medical Center, a tertiary care hospital in Baltimore, Maryland

METHODS

A total of 296 medical or surgical inpatients admitted to non–intensive care unit hospital wards were enrolled at admission from January to November 2010. Patients on contact precautions were individually matched by hospital unit after an initial 3-day length of stay to patients not on contact precautions. Adverse events were detected by physician chart review and categorized as noninfectious, preventable and severe noninfectious, and infectious adverse events during the patient’s stay using the standardized Institute for Healthcare Improvement’s Global Trigger Tool.

RESULTS

The cohort of 148 patients on contact precautions at admission was matched with a cohort of 148 patients not on contact precautions. Of the total 296 subjects, 104 (35.1%) experienced at least 1 adverse event during their hospital stay. Contact precautions were associated with fewer noninfectious adverse events (rate ratio [RtR], 0.70; 95% confidence interval [CI], 0.51–0.95; P=.02) and although not statistically significant, with fewer severe adverse events (RtR, 0.69; 95% CI, 0.46–1.03; P=.07). Preventable adverse events did not significantly differ between patients on contact precautions and patients not on contact precautions (RtR, 0.85; 95% CI, 0.59–1.24; P=.41).

CONCLUSIONS

Hospital ward patients on contact precautions were less likely to experience noninfectious adverse events during their hospital stay than patients not on contact precautions.

Infect. Control Hosp. Epidemiol. 2015;36(11):1268–1274
Turbulent boundary layer statistics at very high Reynolds number
Authors: Vallikivi M. , Hultmark M. , Smits A. J.
Published: August 2015

Measurements are presented in zero-pressure-gradient, flat-plate, turbulent boundary layers for Reynolds numbers ranging from$\mathit{Re}_{{\it\tau}}=2600$to$\mathit{Re}_{{\it\tau}}=72\,500$($\mathit{Re}_{{\it\theta}}=8400{-}235\,000$). The wind tunnel facility uses pressurized air as the working fluid, and in combination with MEMS-based sensors to resolve the small scales of motion allows for a unique investigation of boundary layer flow at very high Reynolds numbers. The data include mean velocities, streamwise turbulence variances, and moments up to 10th order. The results are compared to previously reported high Reynolds number pipe flow data. For$\mathit{Re}_{{\it\tau}}\geqslant 20\,000$, both flows display a logarithmic region in the profiles of the mean velocity and all even moments, suggesting the emergence of a universal behaviour in the statistics at these high Reynolds numbers.
Flow separation at convex banks in open channels
Authors: Blanckaert K.
Published: August 2015

Laboratory experiments in an open channel bend provide insight into the physics of convex bank flow separation occurring in a variety of channel configurations, including confluences and bifurcations. The edge of the zone of flow separation is characterized by a shear layer, enhanced velocity gradients, tke, turbulent shear stresses and reversal of the streamwise vorticity and vertical velocity. The latter result from turbulence-induced secondary flow near the convex bank. When bankline curvature abruptly increases, flow tends to move away from the convex bank along a straight path, as represented by the inertial forces – including the centrifugal force – in the transverse momentum equation written in curvilinear coordinates. Mass accumulation at the opposite bank leads to a transverse tilting of the water surface, and a pressure gradient towards the convex bank that causes the flow to change direction. The pressure gradient force lags spatially behind the inertial forces, which promotes flow separation. Flow separation typically occurs downstream of the location of maximum change in the bankline curvature, because an abrupt increase in bankline curvature also leads to water surface gradients that cause local flow redistribution towards the convex bank that opposes flow separation. The zone of convex bank flow separation is shaped by the secondary flow induced by streamline curvature and turbulence. The latter is conditioned by the production rate of tke, which crucially depends on the accurate description of the Reynolds stresses. Hydrodynamic, geometric and sedimentologic control parameters of convex bank flow separation are identified and discussed.
The asymptotic downstream flow of plane turbulent wall jets without external stream
Authors: Gersten Klaus
Published: August 2015

The plane turbulent wall-jet flow without externally imposed stream is considered. It is assumed that the wall jet does not emerge from a second wall perpendicular to the velocity vector of the initial wall jet. The (kinematic) momentum flux$K(x)$of the wall jet decreases downstream owing to the shear stress at the wall. This investigation is based on the hypothesis that the total friction force on the wall is smaller than the total inflow momentum flux. In other words, the turbulent wall jet tends to a turbulent ‘half-free jet’ with a non-zero momentum flux$K_{\infty }\;(\text{m}^{3}~\text{s}^{-2})$far downstream. The fact that the turbulent half-free jet is the asymptotic form of a turbulent wall jet is the basis for a singular perturbation method by which the wall-jet flow is determined. It turns out that the ratio between the wall distance$y_{m}$of the maximum velocity and the wall distance$y_{0.5}$of half the maximum velocity decreases downstream to zero. Dimensional analysis leads immediately to a universal function of the dimensionless momentum flux$K(\mathit{Re}_{x})/K_{\infty }$that depends asymptotically only on the local Reynolds number$\mathit{Re}_{x}=\sqrt{(x-x_{0})K_{\infty }}/{\it\nu}$, where$x_{0}$denotes the coordinate of the virtual origin. When the values$K$and${\it\nu}$at the position$x-x_{0}$are known, the asymptotic momentum flux$K_{\infty }$can be determined. Experimental data on all turbulent plane wall jets (except those emerging from a second plane wall) collapse to a single universal curve. Comparisons between available experimental data and the analysis make the hypothesis$K_{\infty }\neq 0$plausible. A convincing verification, however, will be possible in the future, preferably by direct numerical simulations.