bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discrete element modeling of dynamic behaviors of railway ballast under cyclic loading with dilated polyhedra
Authors: Ji S. , Sun S. , Yan Y. 
Published: July 2016

SummaryThe dynamic behaviors of railway ballast under cyclic loading are simulated with discrete element method (DEM). Dilated polyhedra are constructed based on the Minkowski sum operator in order to resemble the irregular shapes of ballast particles. The polyhedral particle generation, contact detection between particles and contact laws are presented. Ballast box tests with periodic lateral boundaries are conducted to simulate the dynamics of the sleeper and ballast particles. The settlement and effective stiffness of ballast bed are investigated under cyclic loadings with five distinct frequencies. The settlement of ballast bed is significant in the first several cycles and increases with the number of cycles gradually. The higher frequency loading generates larger displacement in the same simulation time. The effective stiffness of ballast bed increases gradually. To study the effect of particles' sharpness, dilated polyhedra with different dilating radii and spherical particles are also developed. Simulation results show the sharper the ballast particles are, the smaller the produced settlement. Copyright © 2016 John Wiley & Sons, Ltd.
The improved H∞ controller design for nonlinear networked control systems with random communication delays
Authors: Nian Xiaohong , Dai Liqiong , Sun Miaoping , Wang Haibo , Guo Hua 
Published: July 2016

SummaryThis paper is concerned with the observer‐based H∞ controller design problem for nonlinear networked control systems with random communication delays. Firstly, the dynamic observer‐based control scheme is modelled, where the control input of the observer is different from the control input of the plant. Then, a less conservative delay‐dependent H∞ stabilization criterion is derived by using an improved Lyapunov function. And the proof of stabilization criterion is completed in terms of four cases when the time delays in two communication channels are constant or time‐varying, respectively. The derived stabilization criterion is formulated in the form of a non‐convex matrix inequality, which can be solved by an optimal cone complementary linearization iteration algorithm to obtain the minimum disturbance attenuation level. Finally, several numerical examples and an illustrative example are provided to clarify the effectiveness and merits of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd.
Highly purified eicosapentaenoic acid ameliorates cardiac injury and adipose tissue inflammation in a rat model of metabolic syndrome
Authors: Ito S. , Sano Y. , Nagasawa K. , Matsuura N. , Yamada Y. , Uchinaka A. , Murohara T. , Nagata K. 
Published: July 2016

SummaryIntroductionn‐3 Polyunsaturated fatty acids such as eicosapentaenoic acid (EPA), which are abundant in fish oil, have been shown to delay the onset of cardiovascular events. We previously established DahlS.Z‐Leprfa/Leprfa (DS/obese) rats, which are derived from a cross between Dahl salt‐sensitive and Zucker rats, as a model of metabolic syndrome. This study has now explored the influence of highly purified EPA on cardiac and adipose tissue pathophysiology in this animal model.Materials and methodsDS/obese rats were administered EPA (300 or 1,000 mg kg−1 d−1, per os) or vehicle from age 9 to 13 weeks. Homozygous lean (DahlS.Z‐Lepr+/Lepr+, or DS/lean) littermates were studied as controls.ResultsWhereas EPA had no effect on body weight, food intake or systolic blood pressure in DS/obese rats, it attenuated cardiac fibrosis, diastolic dysfunction, oxidative stress and inflammation in these animals. In addition, EPA did not affect insulin resistance but reduced adipocyte hypertrophy and inflammation in visceral fat of DS/obese rats. Moreover, EPA increased circulating levels of adiponectin as well as attenuated both the down‐regulation of AMP‐activated protein kinase phosphorylation and the up‐regulation of phosphorylation of the p65 subunit of nuclear factor‐kB in the heart of DS/obese rats.ConclusionsTreatment of DS/obese rats with EPA did not affect hypertension but reduced cardiac fibrosis and diastolic dysfunction, with the latter effects being accompanied by AMP‐activated protein kinase activation and inactivation of nuclear factor‐kB signalling in the heart, possibly as a result of an increase in adiponectin secretion. EPA may be suitable for the treatment of cardiac injury associated with metabolic syndrome.
Adolescent versus parent reports on asthma and asthma symptoms
Authors: Romano‐Zelekha Orly , Graif Yael , Sultan Serine , Livne Irit , Shohat Tamy 
Published: July 2016

SummaryPurposeEpidemiological studies of asthma in adolescence commonly rely on self‐reports. This study aimed to compare adolescent and parent reports regarding the presence of asthma and asthma symptoms in two ethnic groups, Jews and Arabs, living in the same country.MethodsEighth‐grade pupils attending five schools in Tel Aviv and four schools in two Arab cities in Israel were asked to complete the self‐report International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire in the classroom. Their parents were interviewed by telephone using the parental ISAAC questionnaire. We assessed prevalence rates of asthma and asthma symptoms according to adolescent and parent responses. Agreement between adolescents and parents was assessed by Cohen's kappa coefficient.ResultsAdolescents reported more asthma and asthma symptoms than their parents in both the Jewish (327 adolescent‐parent pairs) and the Arab (335 adolescent‐parent pairs) groups. Both groups showed moderate adolescent‐parent chance‐corrected agreement for current asthma (kappa 0.59 in Jews, 0.52 in Arabs, P = 0.60) and lifetime asthma (kappa 0.53 Jews, 0.44 in Arabs, P = 0.33); and slight to fair chance‐corrected agreement for asthma symptoms. There were no statistically significant differences between the Jewish and Arab populations in chance‐corrected agreement for any of the parameters assessed.ConclusionsJewish and Arab adolescents more often report asthma and asthma symptoms than do their parents. This seems to be a cross‐cultural phenomenon. Therefore, particular attention should be paid to the source of information when comparing prevalence of asthma and asthma symptoms across studies. Pediatr Pulmonol. 2017;52:154–159. © 2016 Wiley Periodicals, Inc.
Eradication of methicillin resistant Staphylococcus aureus detected for the first time in cystic fibrosis: A single center observational study
Authors: Kappler Matthias , Nagel Felicitas , Feilcke Maria , Kröner Carolin , Pawlita Ingo , Naehrig Susanne , Ripper Jan , Hengst Meike , von Both Ulrich , Forstner Maria , Hector Andreas , Griese Matthias 
Published: July 2016

SummaryObjectiveTo retrospectively identify CF patients with methicillin resistant Staphylococcus aureus (MRSA) and to assess the long‐term success of an eradication scheme introduced in 2002 for all newly colonized patients.PatientsAll microbiological results from all 505 CF patients followed between 2002 and 2012 were analyzed focusing on the detection of MRSA.MethodsRetrospective patient record analysis of MRSA positive CF patients regarding eradication and clinical outcome.ResultsWe identified 57 patients with MRSA, mean age 15.3 years (range: 0.6–36.9, incidence 0.9%/year). Of these, nine patients were lost to follow‐up; seven chronically colonized patients were excluded from the intervention. Eradication was suggested to all patients, 37/41 gave their consent to the following two‐step approach: (i) dual iv antibiotic treatment over 3 weeks, accompanied by hygienic directives and topical therapy for 5 days followed by a 6‐week period with dual oral antibiotic therapy and inhalation with vancomycin. (ii) Each new MRSA detection was treated with 6 weeks inhalation of vancomycin and topical therapy for 5 days. Long‐term eradication was rated by the microbiological status in the third year after first detection. MRSA was eradicated in 31 of 37 patients (84%) whose clinical course was stable (mean FEV1 one year before MRSA 80.4%, 3 years after MRSA 81.0%).ConclusionsMRSA colonization mandates complex and expensive hygienic measures which are not well accepted by patients. Therefore, MRSA eradication is desirable. Intensive therapy regimens may be successful in patients with CF and might help to maintain a stable clinical course. Pediatr Pulmonol. 2016;51:1010–1019. © 2016 Wiley Periodicals, Inc.
Quantum information entropy of Eckart potential
Authors: Pooja  , Kumar R. , Kumar G. , Kumar R. , Kumar Anil 
Published: July 2016

AbstractIn this work, the position and momentum space information densities of the Eckart potential are graphically demonstrated and their properties are studied. The position space information densities have quite an asymmetric shape depending on the values of quantum numbers. The information entropy is obtained and Bialynicki‐Birula and Mycielski inequality is numerically saturated for some parameters of the potential. It is shown that the inequality is saturated with increasing potential depth.
Characterization of phenolic compounds in coal tar by gas chromatography/negative‐ion atmospheric pressure chemical ionization mass spectrometry
Authors: Ma Sutian , Ma Chao , Qian Kejun , Zhou Yasong , Shi Quan 
Published: July 2016

RationalePhenolic compounds are commonly found in fossel fuels and bio‐oils, and have a detrimental effect on the chemical stability of the fuels. A selective analytical method is needed to characterize the phenolic compounds in complex hydrocarbon mixtures.MethodsGas chromatography/atmospheric pressure chemical ionization mass spectrometry (GC/APCI‐MS) was used to characterize the phenolic compounds in a low‐temperature coal tar and its narrow distillate fractions.ResultsNegative‐ion APCI selectively ionized phenolic compounds in the coal tar. The [M–H]− and [M–H + O]− ions were derived from monohydric phenols, while [M–H]−, [M‐2H]−, and [M–2H + O]− were from benzenediols. Monohydric phenolic compounds with 1–4 aromatic rings and some dihydric phenolic compounds were identified. The results from GC/APCI‐MS were validated by those from negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICRMS).ConclusionsNegative‐ion GC/APCI‐MS was proposed and successfully used to characterize phenolic compounds in coal tar samples. This technique can potentially be used for the characterization of phenolic compounds in other complex hydrocarbon systems. Copyright © 2016 John Wiley & Sons, Ltd.
Studies on the Mechanism of Fluorescence Quenching of CdS quantum dots by 2‐Amino‐7‐Nitrofluorene and 2‐(N,N‐dimethylamino)‐7‐Nitrofluorene
Authors: Dandpat Shiba Sundar , Sahu Prabhat Kumar , Sarkar Moloy 
Published: July 2016

AbstractMechanism for fluorescence quenching of CdS quantum dots in presence of 2‐Amino‐7‐Nitrofluorene (ANF) and 2‐(N,N‐dimethylamino)‐7‐Nitrofluorene (DMANF) has been investigated using steady‐state and time‐resolved fluorescence spectroscopy. Lowering of emission intensity along with a reduction in average lifetime of CdS quantum dots has been observed with addition of both ANF and DMANF. This quenching is also accompanied with an enhancement in the emission intensity of ANF and DMANF. From these observations, resonance energy transfer is anticipated to take place in the present case. However, a careful analysis of rate constants, Stern‐Volmer plot, steady‐state and lifetime decay profiles showed that the quenching is observed not due to energy transfer, rather due to other competing processes like static quenching and photoinduced charge transfer between the dyads. The high bimolecular quenching rate constants estimated from Stern‐Volmer plot support the presence of static quenching of CdS quantum dots. Analysis of redox potential values of CdS quantum dots, ANF and DMANF has shown the possibility for photoinduced charge transfer in the present systems.
Thickness Dependence of Acidity and Microstructure in Nafion Films
Authors: Singhal Nancy , Datta Anindya 
Published: July 2016

AbstractThin films of Nafion of various thickness viz. 6 and 1 µm, 280, 80 and 33 nm have been probed using the fluorescent molecule 2‐(2′‐pyridyl)benzimidazole (2PBI), at low as well as high hydration levels. The acidity of these films has been found to be less than that of Nafion 117 membrane at hydrated conditions. This has been ascribed to the high water uptake of the films compared to the membrane and the consequent decrease in the local concentration of protons. The fluorophore reports a significant decrease in the acidity of the film upon annealing them, for all values of thickness. Surprisingly, the acidity in annealed film is lesser than in nonannealed films in which H3O+ ions are exchanged with Na+ ions. Acid treatment of the annealed films causes a reversal of this effect, except for the film with thickness less than 80 nm. Thus, pockets inaccessible to proton appear to form in the ultrathin films. The effective proton concentration depends on the thickness of the films and decreases with decrease in thickness of the films. This may be due to the association of protons to sulfonate ions at lower thickness.
Sodium Cyanate Mediated Synthesis of Sulfonylurea and Sulfonyltriuret from Sulfonyl Chloride and Amine
Authors: Hadianawala Murtuza , Shaik Althaf , Hasija Nisha , Vasu Anuji K. , Datta Dr Bhaskar 
Published: July 2016

AbstractSynthetic methods providing access to sulfonylureas are immensely valuable considering the wide usage of sulfonylurea derivatives as hypoglycemic drugs and herbicides. In this work, the scope of a sodium cyanate mediated single‐step synthesis of sulfonylureas from amines and sulfonyl chlorides as starting materials has been examined. Success of the single‐step reaction in affording desired aliphatic and aromatic sulfonylurea products depends on the combination of suitable nucleophilicity of amines and reactivity of sulfonyl chlorides. In addition to providing access to sulfonylureas, the interplay of reactivities of the amine and sulfonyl chloride is found to result in emergence of specific oligomeric products that are characterized as novel sulfonyltriurets. In effect, the sodium cyanate mediated single‐step reaction for synthesis of sulfonylureas also provides a method for synthesis of specific sulfonyltriurets. Electronic effects accompanying the amine and sulfonyl chloride modulate the nature of major product between sulfonylureas and sulfonyltriurets. The sodium cyanate mediated single‐step reaction is thus sought to be considered as a method for synthesis of sulfonyltriurets in addition to sulfonylureas.
Electrochemical Properties of APCVD α‐Fe2O3 Nanoparticles at 300 oC
Authors: Vernardou Dimitra , Apostolopoulou Maria , Katsarakis Nikolaos , Koudoumas Emmanouil , Drosos Charalampos , Parkin Ivan P. 
Published: July 2016

AbstractThe growth of hematite (FeIII oxide) by atmospheric pressure chemical vapor deposition was possible at 300 oC by controlling the nitrogen flow rate through the iron precursor bubbler. An increase of crystallinity along with the presence of compact interconnected nanoparticles was observed upon increasing the nitrogen flow rate. The amount of incorporated charge was the highest for the 0.6 L min−1 coating presenting reversibility after a period of 1400 s as obtained from chronoamperometry measurements. Additionally, the charge transfer of lithium‐ions across the FeIII oxide / electrolyte interface was easier enhancing its performance presenting capacitance retention of 94 % after 500 scans. The importance of nitrogen flow rate towards the deposition of an anode with good stability and effective electrochemical behavior is highlighted.
The Mechanism and Modelling of Shunt Current in the Vanadium Redox Flow Battery
Authors: Skyllas‐Kazacos Maria , McCann John , Li Yifeng , Bao Jie , Tang Ao 
Published: July 2016

AbstractTo date, no physical model has been proposed to describe the mechanism of shunt currents in bipolar electrochemical reactors with a common electrolyte manifold. In this paper, we show that under the influence of the cell voltage driving force, the bipolar electrode provides an internal electrical pathway that allows electrons to flow from the negative half‐cell of one cell, to the positive half‐cell of the adjacent cell, leading to self‐discharge reactions that can occur even when the stack is at open‐circuit. This is made possible, by the presence of the interconnecting channels and common electrolyte manifolds that enable the flow of hydrogen or other charge carrying ions to complete the circuit. The larger the number of cells in the cell stack, the larger the number of internal pathways for electrons and protons to flow, so the greater the shunt current losses.
Metagenome Mining: A Sequence Directed Strategy for the Retrieval of Enzymes for Biocatalysis
Authors: Jeffries Jack W. E. , Dawson Natalie , Orengo Christine , Moody Thomas S. , Quinn Derek J. , Hailes Helen C. , Ward John M. 
Published: July 2016

AbstractBiocatalytic reactions are increasingly being used as a sustainable strategy in organic synthesis and it is recognised that there is need for new enzyme discovery. To establish the utility and versatility of a metagenomics approach, metagenomic DNA extracted from the oral cavity was sequenced and used to create an in silico contig library. This enables individual open reading frames, operons or all the enzymes of a particular family to be identified and then retrieved from the original DNA by PCR. As proof of principle a lactate dehydrogenase, a malate dehydrogenase and transketolases were identified in silico, successfully cloned and assayed. This new enzyme retrieval sequence directed method gives constructive access to metagenomic diversity and importantly improves on the low hit rate experienced when using conventional metagenomic screens.
Celecoxib and octreotide synergistically ameliorate portal hypertension via inhibition of angiogenesis in cirrhotic rats
Authors: Gao Jin-Hang , Wen Shi-Lei , Feng Shi , Yang Wen-Juan , Lu Yao-Yao , Tong Huan , Liu Rui , Tang Shi-Hang , Huang Zhi-Yin , Tang Ying-Mei , Yang Jin-Hui , Xie Hui-Qi , Tang Cheng-Wei 
Published: July 2016

AbstractAbnormal angiogenesis is critical for portal hypertension in cirrhosis. Except for etiological treatment, no efficient medication or regime has been explored to treat the early stage of cirrhosis when angiogenesis is initiated or overwhelming. In this study, we explored an anti-angiogenesis effort through non-cytotoxic drugs octreotide and celecoxib to treat early stage of cirrhotic portal hypertension in an animal model. Peritoneal injection of thioacetamide (TAA) was employed to induce liver cirrhosis in rats. A combination treatment of celecoxib and octreotide was found to relieve liver fibrosis, portal venous pressure, micro-hepatic arterioportal fistulas, intrahepatic and splanchnic angiogenesis. Celecoxib and octreotide exerted their anti-angiogenesis effect via an axis of cyclooxygenase-2/prostaglandin E2/EP-2/somatostatin receptor-2, which consequently down-regulated phosphorylation of extracellular signal-regulated kinase (p-ERK)–hypoxia-inducible factor-1α (HIF-1α)–vascular endothelial growth factor (VEGF) integrated signaling pathways. In conclusions, combination of celecoxib and octreotide synergistically ameliorated liver fibrosis and portal hypertension of the cirrhotic rats induced by TAA via the inhibition of intrahepatic and extrahepatic angiogenesis. The potential mechanisms behind the regimen may due to the inactivation of p-ERK–HIF-1α–VEGF signaling pathway.
Evaluating ship superstructure aerodynamics for maritime helicopter operations through CFD and flight simulation
Authors: Forrest J.S. , Kaaria C.H. , Owen I. 
Published: July 2016

ABSTRACTThe unsteady air flow over and around the helicopter landing deck of a naval vessel is known to cause high pilot workload and to limit the helicopter's operational envelope for launch and recovery. Previous research has suggested that modifications to the ship's hangar edges can beneficially modify the flow over the deck. This paper examines the effectiveness of five hangar-edge modifications using computational fluid dynamics–generated airwakes and flight mechanics modelling, as well as piloted flight trials in a motion-base simulator. Results are presented, in terms of unsteady helicopter loads and pilot workload ratings, for modifications to the windward vertical rear edge of the hangar and with an oblique wind. The results demonstrate that while the airwake can be altered by superstructure modifications, the integrated effect of the altered airwake on the entire helicopter does not necessarily give the desired result; indeed of the five modifications tested, two were seen to be beneficial while three caused an increase in pilot workload compared with the unmodified hangar. Overall, the paper shows that the airwake can be modified by superstructure design changes, and that the effect on the helicopter can be measured through modelling and simulation. It is also demonstrated that making judgements on the severity of the airwake based on the aerodynamic flow field alone can be misleading. The benefit of these simulation tools is that they can be used during the ship design process to evaluate the effect of the superstructure aerodynamics, rather than wait until after the ship is built.
The Corporate Social Performance of Developing Country Multinationals
Authors: Zyglidopoulos Stelios , Williamson Peter , Symeou Pavlos 
Published: July 2016

ABSTRACT:In this article, we explore the Corporate Social Performance (CSP) of Developing Country Multinationals (DMNCs). We argue that in competing internationally, DMNCs often face both reputation and legitimacy deficits, which they address by improving their CSP. We develop a series of hypotheses to explain the variation in CSP between DMNCs and domestic-only firms from developing countries and also examine variations in CSP between DMNCs depending on the extent of their multinationality and portfolio of host countries. Our findings support all our hypotheses, which suggest that DMNCs display enhanced levels of CSP compared to their domestic-only counterparts. CSP is also found to be positively related to the DMNCs’ degree of multinationality, but with a declining incremental impact, whereas entry into developed markets leads to a greater improvement in DMNCs’ CSP than expansion into developing markets. We highlight the implications of our findings for managers and researchers.
OPEN QUESTIONS ABOUT RAMSEY-TYPE STATEMENTS IN REVERSE MATHEMATICS
Authors: PATEY LUDOVIC 
Published: July 2016

AbstractRamsey’s theorem states that for any coloring of then-element subsets of ℕ with finitely many colors, there is an infinite setHsuch that alln-element subsets ofHhave the same color. The strength of consequences of Ramsey’s theorem has been extensively studied in reverse mathematics and under various reducibilities, namely, computable reducibility and uniform reducibility. Our understanding of the combinatorics of Ramsey’s theorem and its consequences has been greatly improved over the past decades. In this paper, we state some questions which naturally arose during this study. The inability to answer those questions reveals some gaps in our understanding of the combinatorics of Ramsey’s theorem.