bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molybdenum anchored on NH2‐modified spherical SiO2: A highly efficient and stable catalyst for oxidative desulfurization of fuel oil
Authors: Hu Zhen , Lu Shuxiang , Huang Xiaoqiao , Li Jianxin , Duan Yongsheng , Yan Lijun , Yao Yue , Liao Xiaoyuan 
Published: August 2018

A catalyst (Mo‐NH2‐SiO2) has been synthesized via anchoring of Mo species onto the surface of 3‐aminopropyltriethoxysilane‐modified SiO2 (NH2‐SiO2) and applied in the catalytic oxidative desulfurization of fuel oil. Structure and properties of the catalyst were investigated using X‐ray diffraction, transmission electron microscopy, X‐ray photoelectron and Fourier transform infrared spectroscopies and nitrogen adsorption–desorption measurements. The hydrophilic/hydrophobic characters of the catalyst were also studied. The results demonstrated that the synthesized catalyst possessed highly dispersed Mo species with an electron‐rich state and a strong hydrophobic character, which contributed significantly to increases of both catalytic activity and stability. Dibenzothiophene in model oil could be removed completely, and the removal of sulfur from diesel oil (21 500 ppmw) also reached 80.4% at 60°C in 60 min. Furthermore, the catalyst was recycled in ten reaction runs without obvious influence on activity. This work provides a novel way for preparing high‐activity and stable catalysts for oxidative desulfurization of fuel oil, which will have potential industrial applications.
Using fish scales (Sardina pilchardus) within ethylene‐propylene‐diene ter monomer rubber as bio‐based filler
Authors: Akbay İsmail Kutlugün , Güngör Ahmet , Özdemir Tonguç 
Published: August 2018

ABSTRACTProper management of waste bio‐based materials is an important subject to protect the environment in a sustainable manner. In this study, ethylene‐propylene‐diene monomer (EPDM) composites with different fish scale content were prepared and properties of these composites were investigated. Mechanical tests, gel content, curing, and thermal properties were analyzed. In addition, rheological and morphological analyses were also carried out. It was seen that EPDM rubber and fish scale composite have a good compatibility. The addition of fish scale improved the mechanical properties of the final material. Moreover, an increase in gel content and in swelling ratio was obtained for the composite samples containing fish scale. Moving die rheometer tests are concluded that fish scale has acted like an agent that improves the vulcanization process. Thermal gravimetric analysis result pointed out that the thermal stability of the composite developed is higher than neat EPDM. It was concluded that 40 phr fish scale content gives best results. The kinetic study demonstrated that fish scale is compatible with the matrix and improves the vulcanization process. The results have shown that using the fish scale as a bio‐based filler is a facile and green way to accommodate the bio‐based wastes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46698.
g‐C3N4 Inverse Opals with Isotype Heterostructure for Enhanced Visible‐Light‐Driven Photocatalysis
Authors: Yu Jie , Zhou Liang , Lei Juying , Wang Lingzhi , Zhang Jinlong , Liu Yongdi 
Published: August 2018

AbstractThe photocatalytic activity of g‐C3N4 is limited by the low surface area and the fast recombination of photogenerated charges. In this work, a g‐C3N4 quantum dot (CNQDs) modified g‐C3N4 inverse opal (CN IO) metal‐free composite (CNQDs/CN IO) was successfully synthesized by a simple calcination method. CNQDs/CN IO exhibited outstanding photocatalytic activity in the removal of organic pollutants represented by phenol, which can be ascribed to (i) the inverse opal structure that enhances the light harvesting, facilitates mass transfer, and provides adequate surface area for photocatalytic reactions; (ii) the incorporation of CNQDs in the framework of g‐C3N4 promotes photogenerated charge separation and transfer across the interfaces between CN IO and CNQDs, leading to excellent photoelectrochemical properties. The strategy of self‐modification of g‐C3N4 with special structures provides a rational design idea to fabricate highly efficient metal‐free photocatalysts.
Heuristic policies for stochastic knapsack problem with time‐varying random demand
Authors: Lu Yingdong 
Published: August 2018

AbstractIn this paper, we consider the classic stochastic (dynamic) knapsack problem, a fundamental mathematical model in revenue management, with general time‐varying random demand. Our main goal is to study the optimal policies, which can be obtained by solving the dynamic programming formulated for the problem, both qualitatively and quantitatively. It is well known that, when the demand size is fixed and the demand distribution is stationary over time, the value function of the dynamic programming exhibits extremely useful first‐ and second‐order monotonicity properties, which lead to monotonicity properties of the optimal policies. In this paper, we are able to verify that these results still hold even in the case that the price distributions are time dependent. When we further relax the demand size distribution assumptions and allow them to be arbitrary, for example, in random batches, we develop a scheme for using value function of alternative unit demand systems to provide bounds to the value function. These results confirm some of the basic understandings of the stochastic knapsack problem. As a natural consequence, we propose a new class of heuristic policies, two‐dimensional switch‐over policies, and discuss numerical procedures for optimizing the parameters of the policies. Extensive numerical experiments demonstrate that these switch‐over policies can provide performances that are in a close neighborhood of the optimum statistically.
Study on fluorescence properties of HCV antiviral (velpatasvir) and its fluorimetric determination in presence of sofosbuvir; application to stability study and human plasma
Authors: Omar Mahmoud A. , Abdel‐Lateef Mohamed A. , Ali Ramadan , Derayea Sayed M. 
Published: August 2018

AbstractVelpatasvir (VLP) is a new, oral, direct‐acting antiviral with potent inhibitory activity against all hepatitis C virus (HCV) genotypes. A highly sensitive, simple, fast and specific one fluorometric method for determination of VLP in the presence of sofosbuvir was developed and validated. The fluorescence behavior of VLP in different organic solvents was examined and explained. Methanol was concluded to be the best sensitizing reagent. The native fluorescence intensity of VLP was accomplished at 383 nm with 339 nm for excitation wavelength. The impacts of experimental variables included pH, various organized media, and time of stability were examined and optimized. A linear relationship was achieved between the VLP concentration and the fluorescence intensity in a range of 5 to 5 × 103 ng mL−1 with 0.70 and 0.23 ng mL−1, for quantitation and detection limits respectively. The proposed method was utilized for analyzing of VLP in human plasma and additionally expanded to examine the stability of VLP after its exposure to various stress conditions, like oxidative, alkaline, acidic, UV, daylight and sunlight conditions, according to ICH guidelines. Furthermore, the kinetics of acidic and oxidative degradations of VLP was examined. Moreover, the half‐life times of the reaction (t1/2) and the first‐order reaction rate constants were estimated. Finally, a suggestion for the degradation pathway was presented.
Steamed bread—A review of manufacturing, flour quality requirements, and quality evaluation
Authors: Huang Sidi , Miskelly Diane 
Published: August 2018

AbstractBackground and objectivesSteamed bread is a staple food in northern China and is also popular in the south of China and many Asian countries. It is a fermented food made from wheat flour, and the steaming process gives a product with a thin, white skin, an upright profile, and internal crumb ranging from dense and firm to open and soft, depending on the style and region.FindingsThis review presents an overview of the major manufacturing methods in commercial production and the factors influencing product quality, including processing and flour quality. Forty years of research has helped refine wheat quality requirements for the different styles of steamed bread, but there are still conflicting reports on basic wheat quality requirements and ingredient effects which hinder progress in the field.ConclusionsIn order for manufacturers to obtain the flour quality they require, all sectors of the chain must work to understand the interaction of production method and flour quality for each style of steamed bread and each region. This includes development and implementation of objective methods of steamed bread quality assessment.Significance and noveltyBy considering both the style of steamed bread and method of manufacture as described in this review, it is possible to select the most appropriate methods and quality evaluation parameters. This should enable future researchers to present conclusions which may be useful to later workers.
Photocatalysis for Hydrogen Production and CO2 Reduction: The Case of Copper‐Catalysts
Authors: Christoforidis Konstantinos C. , Fornasiero Paolo 
Published: August 2018

AbstractProblems derived from climate change dictate the reestablishment of our prospective in energy production. In this direction, converting solar energy through photocatalysis into suitable fuels such as hydrogen and carbon‐based fuels by water splitting and CO2 reduction, respectively, has been established as a promising approach. Currently, the main concern in this field is the development of cost‐effective and efficient photocatalysts. Among the different systems studied, Cu‐based photocatalysts are considered attractive candidates for both applications due to their relative low‐cost, the natural abundance of the constituents and their promising reactivity. In this review, the current progress in the field of Cu‐based photoactive materials for both H2 production and CO2 reduction will be discussed. Finally, an outlook on the challenges and future research directions is given.
Catalytic Amplification of Au144 Nanocluster Collisions by Hydrogen Evolution Reaction
Authors: Zhou Min , Wang Dengchao , Mirkin Michael V. 
Published: August 2018

AbstractQuantification of the charge‐transfer kinetics at single catalytic nanoparticles is both, challenging and crucial for fundamental understanding and practical application in catalysis and energy storage. We report here the quantification of catalytic activity of single Au144 nanoclusters towards hydrogen evolution reaction in mixed organic media. The electrocatalytic amplification by the proton reduction reaction was used to detect current spikes produced by collisions of single Au144 nanoclusters (1.6 nm in diameter) with a carbon ultramicroelectrode. Relatively short (ms‐scale) current spikes were recorded at the naturally hydrophilic carbon surface, while longer (seconds) collision current responses were observed at the hydrophobic carbon fibre electrode treated by acetone. The kinetics of the hydrogen evolution reaction at a single Au nanocluster was evaluated by measuring the amplitudes of current spikes at different overpotentials. The relationship between the current amplitude and the overpotential yielded a linear Tafel plot with the 114 mV/decade slope. This approach is potentially useful for quantifying the electron‐transfer kinetics at singe catalytic nanoclusters and larger nanoparticles.
Chemometrical study of spectral curve fitting constraint on self‐modelling curve resolution methods
Authors: Khodadadi Karimvand Somaiyeh , Abdollahi Hamid 
Published: August 2018

AbstractRotational ambiguity is a significant concern of chemometricians when using soft modeling methods to resolve bilinear data. Applying different types of constraints appropriate to a system under study can significantly reduce rotational ambiguity in soft models and the resulting range of feasible solutions. The first and most commonly used constraint is non‐negativity and can be applied to concentration and spectral response profiles as appropriate. Unimodality constraints, trilinearity constraints, and physical chemical modeling of concentration profiles are natural constraints that can significantly reduce rotational ambiguity in soft modeling curve resolution methods. Also, functional fitting of spectral response profiles (eg, peak shape modeling) has been used as a constraint for resolving spectroscopic data matrices. In the present work, the use of peak shape model constraints for spectral profiles was investigated using the Voigt function (a combination of Gaussian and Lorentzian functions). Mixture spectra of a simulated two‐component system and a real data set were fitted to several different Voigt models.The results of applying peak shape models on the range of feasible solutions for simulated and real data sets and simultaneously fitting the data to different models show that spectral peak shape constraints are not effective for limiting the range of feasible bands. Indeed, the non‐specific spectral Voigt model does not provide enough information about spectra to be effective for significant reduction of rotational ambiguity. These studies show that in the absence of sufficient information, many sets of peak functions can be well‐fitted to spectra and rotational ambiguity is not improved when resolving bilinear spectroscopic data.
Diferrate [Fe2(CO)6(μ‐CO){μ‐P(aryl)2}]− as Self‐Assembling Iron/Phosphor‐Based Catalyst for the Hydrogen Evolution Reaction in Photocatalytic Proton Reduction—Spectroscopic Insights
Authors: Fischer Steffen , Rösel Arend , Kammer Anja , Barsch Enrico , Schoch Roland , Junge Henrik , Bauer Matthias , Beller Matthias , Ludwig Ralf 
Published: August 2018

AbstractThis work is focused on the identification and investigation of the catalytically relevant key iron species in a photocatalytic proton reduction system described by Beller and co‐workers. The system is driven by visible light and consists of the low‐cost [Fe3(CO)12] as catalyst precursor, electron‐poor phosphines P(R)3 as co‐catalysts, and a standard iridium‐based photosensitizer dissolved in a mixture of THF, water, and the sacrificial reagent triethylamine. The catalytic reaction system was investigated by operando continuous‐flow FTIR spectroscopy coupled with H2 gas volumetry, as well as by X‐ray absorption spectroscopy, NMR spectroscopy, DFT calculations, and cyclic voltammetry. Several iron carbonyl species were identified, all of which emerge throughout the catalytic process. Depending on the applied P(R)3, the iron carbonyl species were finally converted into [Fe2(CO)6(μ‐CO){μ‐P(R)2}]−. This involves a P−C cleavage reaction. The requirements of P(R)3 and the necessary reaction conditions are specified. [Fe2(CO)6(μ‐CO){μ‐P(R)2}]− represents a self‐assembling, sulfur‐free [FeFe]‐hydrogenase active‐site mimic and shows good catalytic activity if the substituent R is electron poor. Deactivation mechanisms have also been investigated, for example, the decomposition of the photosensitizer or processes observed in the case of excessive amounts of P(R)3. [Fe2(CO)6(μ‐CO){μ‐P(R)2}]− has potential for future applications.
Hybridization of Pd Nanoparticles with UiO‐66(Hf) Metal‐Organic Framework and the Effect of Nanostructure on the Catalytic Properties
Authors: Bakuru Vasudeva Rao , Velaga Bharath , Peela Nageswara Rao , Kalidindi Suresh Babu 
Published: August 2018

AbstractMetal‐organic frameworks (MOFs) have emerged as a new class of supports for metal nanoparticles(NPs) in heterogeneous catalysis because of possible synergetic effects between the two components. In addition, MOFs also can be coated over metal NPs to influence the entire nanoparticle's surface. Herein, NPs were hybridized with UiO‐66(Hf) MOF possessing Brønsted acidic sites (on secondary building units) and fabricated Pd@UiO‐66 (Hf) core–shell and Pd/UiO‐66(Hf) supported catalysts. These hybrid materials exhibited enhanced catalytic properties (TOF increased up to 2.5 times) compared to individual counterparts or their physical mixture for dehydrogenation of ammonia borane(AB) in non‐aqueous medium(1,4‐dioxane). Further, nanostructure of the hybrid material had pronounced influence on the catalytic properties. The core–shell catalyst exhibited highest activity towards H2 generation from AB owing to greater contact interface between Pd and MOF. Further, phenylacetylene semi‐hydrogenation with AB over Pd@UiO‐66 (Hf) furnished styrene selectivity as high as 93.2 % at ∼100 % conversion mostly due to the regulated phenylacetylene diffusion through UiO‐66(Hf) shell.
Synthesis of (±)‐Merrilactone A by a Desymmetrization Strategy
Authors: Liu Wentan , Wang Bo 
Published: August 2018

AbstractA concise synthesis of (±)‐merrilactone A has been accomplished featuring desymmetrization of a Cs‐symmetric dilactone, RhI‐catalyzed intramolecular hydroacylation of a 4‐alkynal, and TiIII‐mediated reductive radical cyclization of epoxy‐allene.
Design of a Production Process for Poly(oxymethylene) Dimethyl Ethers from Dimethyl Ether and Trioxane
Authors: Breitkreuz Christian Frederik , Schmitz Niklas , Ströfer Eckhard , Burger Jakob , Hasse Hans 
Published: August 2018

AbstractPoly(oxymethylene) dimethyl ethers (OME) are promising synthetic fuels. When compared to fossil diesel fuel, OME reduce the soot formation in diesel engines. OME can be produced from the C1 platform syngas via different routes. This work investigates an OME production process via dimethyl ether and trioxane. The process is simulated and optimized using process simulation with varying model depth. As no experimental data are available on the chemical equilibrium of the reaction of dimethyl ether and trioxane, chemical equilibrium constants are partly estimated from formation data of the reactants.
Predictors of long‐term mortality with cardiac resynchronization therapy in mild heart failure patients with left bundle branch block
Authors: Biton Yitschak , Costa Jason , Zareba Wojciech , Baman Jayson R. , Goldenberg Ilan , McNitt Scott , Solomon Scott D. , Polonsky Bronislava , Kutyifa Valentina 
Published: August 2018

BackgroundCardiac resynchronization therapy (CRT) is highly beneficial in patients with heart failure (HF) and left bundle branch block (LBBB); however, up to 30% of patients in this selected group are nonresponders.HypothesisWe hypothesized that clinical and echocardiographic variables can be used to develop a simple mortality risk stratification score in CRT.MethodsBest‐subsets proportional‐hazards regression analysis was used to develop a simple clinical risk score for all‐cause mortality in 756 patients with LBBB allocated to the CRT with defibrillator (CRT‐D) group enrolled in the multicenter automatic defibrillator implantation trial with cardiac resynchronization therapy. The score was used to assess the mortality risk within the CRT‐D group and the associations with mortality reduction with CRT‐D vs implantable cardioverter defibrillator (ICD) in each risk category.ResultsFour clinical variables comprised the risk score: age ≥ 65, creatinine ≥ 1.4 mg/dL, history of coronary artery bypass graft, and left ventricular ejection fraction (LVEF) < 26%. Every 1 point increase in the score was associated with 2‐fold increased mortality within the CRT‐D arm (P < 0.001). CRT‐D was associated with mortality reduction as compared with ICD only in patients with moderate risk: score 0 (HR = 0.80, P = 0.615), score 1 (HR = 0.54, P = 0.019), score 2 (HR = 0.54, P = 0.016), score 3‐4 risk factors (HR = 1.08, P = 0.811); however, the device by score interaction was not significant (P = 0.306). The score was also significantly predictive of left ventricular reverse remodeling (P < 0.001).ConclusionsFour clinical variables can be used for improved mortality risk stratification in mild HF patients with LBBB implanted with CRT‐D.
The impact of clinical vs administrative claims coding on hospital risk‐adjusted outcomes
Authors: O'Brien Emily C. , Li Shuang , Thomas Laine , Wang Tracy Y. , Roe Matthew T. , Peterson Eric D. 
Published: August 2018

BackgroundComorbid condition and hospital risk‐adjusted outcomes prevalence were compared based on clinical registry vs administrative claims data.HypothesisRisk‐adjusted outcomes will vary depending on the source of comorbidity data used.MethodsClinical data from hospitalized Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association (ACC/AHA) Guidelines (CRUSADE) non‐ST‐segment elevation myocardial infarction (NSTEMI) patients ≥65 years was linked to Medicare claims. Eight common comorbid conditions were coded and compared between registry data (derived from medical record review) and claims data; hospital‐level observed vs expected ratios and outlier status for 30‐day readmission and mortality were calculated using logistic generalized estimating equations for clinical vs claims data.ResultsOf 68 199 NSTEMI patients, 48.1% were female, 86.9% were white, and median age was 78. Degree of agreement between data sources for comorbid condition prevalence was 67.8% for myocardial infarction and 89.3% for diabetes. Overall, multivariable model performance was similar: Medicare mortality c‐statistics is 0.69 vs CRUSADE is 0.71; readmission c‐statistics is 0.59 for both. Hospital ratings were similar regardless of data source (mortality, R2 = 0.97863; readmission, R2 = 0.97858). Eighty‐two hospitals were mortality outliers in claims‐based models; of these, 70 were outliers in registry‐based models. Forty‐five hospitals were readmission outliers in claims‐based models; of these, 39 were outliers in registry‐based models.ConclusionsThere were significant differences in individual comorbid condition prevalence when derived from registries vs claims, but hospital‐level outcomes were comparable.
Effect of node centrality for IoT device selection in opportunistic networks: A comparison study
Authors: Cuka Miralda , Elmazi Donald , Bylykbashi Kevin , Spaho Evjola , Ikeda Makoto , Barolli Leonard 
Published: August 2018

SummaryOpportunistic networks (Oppnets) are a subclass of delay‐tolerant networks where communication opportunities (contacts) are intermittent and there is no need to establish an end‐to‐end link between communication nodes. The Internet of Things (IoT) presents the notion of large networks of connected devices, sharing data about their environments and creating a diverse ecosystem of sensors, actuators, and computing nodes. IoT networks consist of heterogeneous collections of resource constrained nodes that closely interact with their environment. There are different issues for these networks. One of them is the selection of IoT devices to carry out a task in Oppnets. In this work, we implement and compare two fuzzy‐based systems (FBSs) for selecting the IoT device that completes the task in Oppnets. We call these systems FBSIDS1 and FBSIDS2. For FBSIDS1, we use three input parameters: IoT device storage, IoT device waiting time (IDWT), and IoT device remaining energy. The output parameter is IoT device selection decision. For FBSIDS2, we consider four input parameters by adding IoT device node centrality (IDNC) as a new parameter. Comparing the complexity of FBSIDS1 and FBSIDS2, FBSIDS2 is more complex than FBSIDS1. However, FBSIDS2 is more flexible and makes a better selection of IoT devices than FBSIDS1. The simulation results show that IoT device selection is increased up to 33% and 71% by increasing IDNC and IDWT, respectively, for FBSIDS2, and up to 46% and 61% by increasing IDWT and IDNC, respectively, for FBSIDS1.