bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment
Authors: Jang Ji‐Wook , Friedrich Dennis , Müller Sönke , Lamers Marlene , Hempel Hannes , Lardhi Sheikha , Cao Zhen , Harb Moussab , Cavallo Luigi , Heller René , Eichberger Rainer , van de Krol Roel , Abdi Fatwa F. 
Published: August 2017

AbstractWidespread application of solar water splitting for energy conversion is largely dependent on the progress in developing not only efficient but also cheap and scalable photoelectrodes. Metal oxides, which can be deposited with scalable techniques and are relatively cheap, are particularly interesting, but high efficiency is still hindered by the poor carrier transport properties (i.e., carrier mobility and lifetime). Here, a mild hydrogen treatment is introduced to bismuth vanadate (BiVO4), which is one of the most promising metal oxide photoelectrodes, as a method to overcome the carrier transport limitations. Time‐resolved microwave and terahertz conductivity measurements reveal more than twofold enhancement of the carrier lifetime for the hydrogen‐treated BiVO4, without significantly affecting the carrier mobility. This is in contrast to the case of tungsten‐doped BiVO4, although hydrogen is also a donor type dopant in BiVO4. The enhancement in carrier lifetime is found to be caused by significant reduction of trap‐assisted recombination, either via passivation or reduction of deep trap states related to vanadium antisite on bismuth or vanadium interstitials according to density functional theory calculations. Overall, these findings provide further insights on the interplay between defect modulation and carrier transport in metal oxides, which benefit the development of low‐cost, highly‐efficient solar energy conversion devices.
Radikalische Hydrodehalogenierung von Arylbromiden und ‐chloriden mit Natriumhydrid und 1,4‐Dioxan
Authors: Hokamp Tobias , Dewanji Abhishek , Lübbesmeyer Maximilian , Mück‐Lichtenfeld Christian , Würthwein Ernst‐Ulrich , Studer Armido 
Published: August 2017

AbstractEine praktische Methode zur radikalischen Kettenreduktion von diversen Arylbromiden und ‐chloriden wird vorgestellt. In dem thermischen Prozess werden NaH und 1,4‐Dioxan als Reagenzien sowie 1,10‐Phenanthrolin als Initiator eingesetzt. Die Hydrodehalogenierungen können mit typischen radikalischen Cyclisierungsreaktionen kombiniert werden, was ihren radikalischen Charakter belegt. DFT‐Berechnungen und experimentelle Studien stützen den vorgeschlagenen Mechanismus über Elektronenkatalyse.
Application of novel copper organic material for facile microextraction of sodium valproate from human plasma samples: Experimental design optimization and isotherm study
Authors: Bahrani Sonia , Ghaedi Mehrorang , Taghipour Tahere , Mansoorkhani Mohammad Javad Khoshnood , Bagheri Ahmad Reza , Ostovan Abbas 
Published: August 2017

Well‐designed metal organic materials (MOMs) were synthesized and applied for pre‐concentration and determination of sodium valproate (Na‐VP) from biological samples, bound to the copper complex of 1,4‐phenylenedioxydiacetic acid under mild conditions. The channels of this sorbent provide high efficiency and also selectivity. The MOMs were structurally characterized using Fourier transform infrared and energy‐dispersive X‐ray spectroscopies, scanning electron microscopy and X‐ray diffraction, and they were found to have suitable features for quantification of Na‐VP using HPLC coupled with UV detection at λ = 215 nm. Moreover, the rate of adsorption is improved by ultrasonic power and the experimental data are best fitted according to Freundlich adsorption isotherm. According to the central composite design, the best experimental conditions are 280.0 μl, 3.0 min and 17.0 mg for volume of eluent, sonication time and sorbent mass respectively. Calibration plots show linear responses towards Na‐VP concentrations (0.4–18.0 μg ml−1), satisfactory limit of detection (0.06 μg ml−1, S/N = 3) and reasonable enrichment factor (70.58). The coefficient of variation values of both inter‐ and intra‐day analyses were less than 4.0%, indicating a candidate method for the determination of Na‐VP in human plasma with reasonable recovery and efficiency.
Nitro group reduction and Suzuki reaction catalysed by palladium supported on magnetic nanoparticles modified with carbon quantum dots generated from glycerol and urea
Authors: Gholinejad Mohammad , Zareh Fatemeh , Nájera Carmen 
Published: August 2017

Glycerol and urea were used as green and cheap sources of carbon quantum dots (CQD) for modifying Fe3O4 nanoparticles (NPs). The obtained CQD@Fe3O4 NPs were used for the stabilization of palladium species and the prepared catalyst, Pd@CQD@Fe3O4, was characterized using various techniques. This magnetic supported palladium was applied as an efficient catalyst for the reduction of aromatic nitro compounds to primary amines at room temperature using very low palladium loading (0.008 mol%) and also for the Suzuki–Miyaura cross‐coupling reaction of aryl halides as well as challenging heteroaryl bromides and aryl diazonium salts with arylboronic acids and with potassium phenyltrifluoroborate. This magnetically recyclable catalyst was recovered and reused for seven consecutive runs in the reduction of 4‐nitrotoluene to p‐toluidine and for ten consecutive runs in the reaction of 4‐iodoanisole with phenylboronic acid with small decrease of activity. The catalyst reused in the Suzuki reaction was characterized using transmission electron microscopy, vibrating sample magnetometry and X‐ray photoelectron spectroscopy. Using experiments such as hot filtration and poisoning tests, it has been shown that the true catalyst works under homogeneous conditions according to the release–return pathway of active palladium species.
Development of low‐shrinkage composites based on novel crosslinking vinylcyclopropanes
Authors: Tauscher Sven , Catel Yohann , Fässler Pascal , Fischer Urs , Moszner Norbert 
Published: August 2017

ABSTRACTPolymerization shrinkage of methacrylate‐based dental composites remains a major concern in restorative dentistry. Cyclic monomers that undergo ring‐opening polymerization are known to exhibit reduced polymerization shrinkage compared to methacrylates. In this article, the synthesis of four crosslinking 1,1‐disubstituted 2‐vinylcyclopropanes bearing rigid spacers is described. These monomers were synthesized by esterification of 1‐ethoxycarbonyl‐2‐vinylcyclopropane‐1‐carboxylic acid with the corresponding diols. The photopolymerization kinetics of these monomers was investigated by photo‐differential scanning calorimeter using bis(4‐methoxybenzoyl)diethylgermane as the photoinitiator. The synthesized vinylcyclopropanes (VCPs) were shown to be more reactive than the frequently used reactive diluent triethylene glycol dimethacrylate. Composites based on these VCPs showed good mechanical properties and exhibited a significantly reduced volumetric shrinkage and shrinkage stress compared to a corresponding dimethacrylate‐based restorative material. This work highlights the excellent potential of VCPs as alternatives to methacrylates in the development of low‐shrinkage dental composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45577.
Distributed Fixed‐Time Coordinated Tracking for Nonlinear Multi‐Agent Systems Under Directed Graphs
Authors: Ning Boda , Zuo Zongyu , Jin Jiong , Zheng Jinchuan 
Published: August 2017

AbstractThis paper is concerned with the fixed‐time coordinated tracking problem for a class of nonlinear multi‐agent systems under detail‐balanced directed communication graphs. Different from conventional finite‐time coordinated tracking strategies, the fixed‐time approach developed in this paper guarantees that a settling time bound is prescribed without dependence on initial states of agents. First, for the case of a single leader, a distributed protocol based on fixed‐time stability techniques is proposed for each follower to accomplish the consensus tracking in a fixed time. Second, in the presence of multiple leaders, a new distributed protocol is proposed such that states of followers converge to the dynamic convex hull spanned by those of leaders in a fixed time. In addition, for a class of linear multi‐agent systems, sufficient conditions that guarantee the fixed‐time coordinated tracking are provided. Finally, numerical simulations are given to demonstrate the effectiveness of the theoretical results.
Adaptive Terminal Sliding Mode Control for Motion Tracking of a Micropositioning System
Authors: Wang Guangwei , Xu Qingsong 
Published: August 2017

AbstractThis paper presents the design of a novel adaptive terminal sliding mode controller (ATSMC) and its application to motion tracking control of a piezoelectric‐driven micropositioning system. A nonsingular terminal sliding surface is used to achieve fast and finite‐time convergence for the trajectory tracking, and also to avoid the singularity phenomenon in traditional terminal sliding mode design. An adaptive gain law is developed to update the gain of the proposed controller and to provide stable and chattering‐free control action. The stability of the control system has been demonstrated in the sense of Lyapunov. The ATSMC scheme is established based on the output feedback only, which does not require a state observer and facilitates an easy implementation. The proposed controller is implemented on a field‐programmable gate array (FPGA) platform. Comparison study with three conventional controllers has been conducted. Experimental results show the feasibility and effectiveness of the proposed control strategy.
Dynamic Output Feedback Robust MPC With one Free Control Move for LPV Model With Bounded Disturbance
Authors: Ding Baocang , Wang Pengjun , Hu Jianchen 
Published: August 2017

AbstractFor a linear parameter‐varying (LPV) model which is a convex combination of several linear time invariant sub‐models, this paper considers the case when the combining coefficients are unknown (except being nonnegative and their sum being one). For this model with norm‐bounded unknown disturbance, an output feedback robust model predictive control (MPC) is proposed by parameterizing the infinite horizon control moves and estimated states into one free control move, one free estimated state (i.e., one control move and one estimated state as degrees of freedom for optimization) and a dynamic output feedback law. This is the first endeavour to apply the free control move and free estimated state in the output feedback MPC for this model. The algorithm is shown to be recursively feasible and the system state is guaranteed to converge to the neighborhood of the equilibrium point. A numerical example verifies the effectiveness of the proposed algorithm.
Determining Dissipativity of Switched Nonlinear Systems Using Linearization
Authors: Wang Hanmei , Zhao Jun 
Published: August 2017

AbstractLocal strict QSR‐dissipativity of a switched nonlinear system is studied using the linearization technique in this paper. We obtain local strict QSR‐dissipativity of a switched system even if each subsystem is not locally strictly QSR dissipative by designing a switching law. The derived dissipative sufficient condition is characterized by a modified Lyapunov‐Metzler inequality that can be simplified as an LMI by assuming specific forms. Two special forms of local strict QSR‐dissipativity, local input state strict passivity and local L2‐gain, are considered. When the approximate errors of a switched affine system satisfy certain conditions, local strict passivity can be drawn from its linearization. Finally, a numerical example is given to illustrate how to apply the proposed method to achieve passivity of switched nonlinear systems.
Impact of growth mode, phase, and rate on the metabolic state of the extremely thermophilic archaeon Pyrococcus furiosus
Authors: Khatibi Piyum A. , Chou Chung‐jung , Loder Andrew J. , Zurawski Jeffrey V. , Adams Michael W.W. , Kelly Robert M. 
Published: August 2017

AbstractThe archaeon Pyrococcus furiosus is emerging as a metabolic engineering platform for production of fuels and chemicals, such that more must be known about this organism's characteristics in bioprocessing contexts. Its ability to grow at temperatures from 70 to greater than 100°C and thereby avoid contamination, offers the opportunity for long duration, continuous bioprocesses as an alternative to batch systems. Toward that end, we analyzed the transcriptome of P. furiosus to reveal its metabolic state during different growth modes that are relevant to bioprocessing. As cells progressed from exponential to stationary phase in batch cultures, genes involved in biosynthetic pathways important to replacing diminishing supplies of key nutrients and genes responsible for the onset of stress responses were up‐regulated. In contrast, during continuous culture, the progression to higher dilution rates down‐regulated many biosynthetic processes as nutrient supplies were increased. Most interesting was the contrast between batch exponential phase and continuous culture at comparable growth rates (∼0.4 hr−1), where over 200 genes were differentially transcribed, indicating among other things, N‐limitation in the chemostat and the onset of oxidative stress. The results here suggest that cellular processes involved in carbon and electron flux in P. furiosus were significantly impacted by growth mode, phase and rate, factors that need to be taken into account when developing successful metabolic engineering strategies.
Optimization of chemical engineering problems with EMSO software
Authors: Henrique João Paulo , de Sousa Ruy , Secchi Argimiro R. , Ravagnani Mauro A. S. S. , Costa Caliane B. B. 
Published: August 2017

AbstractEMSO software, a free tool for teaching and academic research, presents a favorable environment for simulation and optimization of chemical engineering problems. Although its use in research activities have been demonstrated in the literature, its application as a supporting tool for educational purposes in process systems engineering courses has not been evaluated. The objective of this paper is to demonstrate that this software is suitable as a tool for educational purposes in process systems engineering courses at undergraduate (complementary elective subject) and graduate levels. To accomplish this task, different cases studies, encompassing different sort of programming formulations, are proposed and solved with different solvers in EMSO.
Chemoselective Reduction of Phosphine Oxides by 1,3‐Diphenyl‐Disiloxane
Authors: Buonomo Joseph A. , Eiden Carter G. , Aldrich Courtney C. 
Published: August 2017

AbstractReduction of phosphine oxides to the corresponding phosphines represents the most straightforward method to prepare these valuable reagents. However, existing methods to reduce phosphine oxides suffer from inadequate chemoselectivity due to the strength of the P=O bond and/or poor atom economy. Herein, we report the discovery of the most powerful chemoselective reductant for this transformation to date, 1,3‐diphenyl‐disiloxane (DPDS). Additive‐free DPDS selectively reduces both secondary and tertiary phosphine oxides with retention of configuration even in the presence of aldehyde, nitro, ester, α,β‐unsaturated carbonyls, azocarboxylates, and cyano functional groups. Arrhenius analysis indicates that the activation barrier for reduction by DPDS is significantly lower than any previously calculated silane reduction system. Inclusion of a catalytic Brønsted acid further reduced the activation barrier and led to the first silane‐mediated reduction of acyclic phosphine oxides at room temperature.
Absolute configuration of the ocimene monoterpenoids from Artemisia absinthium
Authors: Julio Luis F. , Burgueño‐Tapia Eleuterio , Díaz Carmen E. , Pérez‐Hernández Nury , González‐Coloma Azucena , Joseph‐Nathan Pedro 
Published: August 2017

AbstractThe absolute configuration (AC) of the naturally occurring ocimenes (−)‐(3S,5Z)‐2,6‐dimethyl‐2,3‐epoxyocta‐5,7‐diene (1) and (−)‐(3S,5Z)‐2,6‐dimethylocta‐5,7‐dien‐2,3‐diol (2), isolated from the essential oils of domesticated specimens of Artemisia absinthium, followed by vibrational circular dichroism (VCD) studies of 1, as well as from the acetonide 3 and the monoacetate 4, both derived from 2, since secondary alcohols are not the best functional groups to be present during VCD studies in solution due to intermolecular associations. The AC follows from comparison of experimental and calculated VCD spectra that were obtained by Density Functional Theory computation at the B3LYP/DGDZVP level of theory. Careful nuclear magnetic resonance (NMR) measurements were compared with literature values, providing for the first time systematic 1H and 13C chemical shift data. Regarding homonuclear 1H coupling constants, after performing a few irradiation experiments that showed the presence of several small long‐range interactions, the complete set of coupling constants for 3, which is representative of the four studied molecules, was determined by iterations using the PERCH software. This procedure even allowed assigning the pro‐R and pro‐S methyl group signals of the two gem‐dimethyl groups present in 3.
Patients without comorbidities at the time of diagnosis of atrial fibrillation: causes of death during long‐term follow‐up compared to matched controls
Authors: Andersson Tommy , Magnuson Anders , Bryngelsson Ing‐Liss , Frøbert Ole , Henriksson Karin M. , Edvardsson Nils , Poçi Dritan 
Published: August 2017

BackgroundLittle is known about the long‐term, cause‐specific mortality risk in patients without comorbidities at the time of diagnosis of atrial fibrillation (AF).MethodsFrom a nation‐wide registry of patients hospitalized with incident AF between 1995 and 2008 we identified 9 519 patients with a first diagnosed AF and no comorbidities at the time of AF diagnosis. They were matched with 12 468 controls. The follow‐up continued until December 2008. Causes of death were classified according to the ICD‐10 codes.ResultsDuring follow‐up, 11.1% of patients with AF and 8.3% of controls died.Cardiovascular diseases were the most common causes of death and the only diagnoses which showed significantly higher relative risk in patients with AF than controls (HR 2.0, 95% CI 1.8‐2.3), and the relative risk was significantly higher in women than in men. Stroke was a more common cause among patients with AF, 13.1% versus 9.7% (HR 2.7, 95% CI 1.8‐4.0), while cerebral hemorrhage was more common among controls, 4.7% versus 10.2% (HR 0.9, 95% CI 0.6‐1.5). The time from AF diagnosis to death was 6.0 ± 3.1 years.ConclusionsIn patients with incident AF and no known comorbidities at the time of AF diagnosis, only cardiovascular diseases were more often causes of death as compared to controls. Women carried a significantly higher relative risk than men.
The role of surgery and adjuvant therapy in lymph node–positive cancers of the gallbladder and intrahepatic bile ducts
Authors: Tran Cao Hop S. , Zhang Qianzi , Sada Yvonne H. , Chai Christy , Curley Steven A. , Massarweh Nader N. 
Published: August 2017

BACKGROUNDLymph node metastasis is a poor prognostic factor for biliary tract cancers (BTCs). The optimal management of patients who have BTC with positive regional lymph nodes, including the impact of surgery and adjuvant therapy (AT), is unclear.METHODSThis was a retrospective cohort study of patients who had T1‐T3N1M0 gallbladder cancer (GBC) and intrahepatic cholangiocarcinoma (IHC) in the National Cancer Database (2004‐2012). Patients were classified by treatment approach (nonoperative, surgery, surgery plus AT). Associations between the overall risk of death and treatment strategy were evaluated with multivariable Cox regression.RESULTSRates of surgical resection were 84.1% for patients with GBC (n = 1335) and 36.6% for those with IHC (n = 1009). The median overall survival of patients in the nonoperative, surgery, and surgery plus AT group was 11.6, 13.3, and 19.6 months, respectively, for those with GBC (log‐rank P < .001), and 12.7, 16.2, and 22.6 months, respectively, for those with IHC (log‐rank P < .001), respectively. Compared with nonoperative therapy, surgery with or without AT was associated with a lower risk of death from GBC (surgery with AT: hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.48‐0.73; surgery without AT: HR, 0.71; 95% CI, 0.56‐0.89) and from IHC (surgery with AT: HR, 0.52; 95% CI, 0.42‐0.63; surgery without AT: HR, 0.70; 95% CI, 0.56‐0.87). AT that included radiation was associated with a lower risk of death relative to surgery alone for patients with GBC regardless of margin status (margin‐negative resection: HR, 0.66; 95% CI, 0.52‐0.84; margin‐positive resection: HR, 0.54; 95% CI, 0.39‐0.75), but adjuvant chemotherapy alone was not. For patients with IHC, no survival benefit was detected with adjuvant chemotherapy or radiation for those who underwent either margin‐positive or margin‐negative resection.CONCLUSIONSThe best outcomes for patients who have lymph node–positive BTCs are associated with margin‐negative resection and, in those who have GBC, the inclusion of adjuvant chemotherapy with radiation regardless of margin status. Cancer 2018;124:74‐83. © 2017 American Cancer Society.
Introducing ToPe‐FFT: An OpenCL‐based FFT library targeting GPUs
Authors: Jan Bilal , Khan Fiaz Gul , Montrucchio Bartolomeo , Chronopoulos Anthony Theodore , Shamshirband Shahaboddin , Khan Abdul Nasir 
Published: August 2017

SummaryIn this paper, we present our implementation of the fast Fourier transforms on graphic processing unit (GPU) using OpenCL. This implementation of the FFT (ToPe‐FFT) is based on the Cooley‐Tukey set of algorithms with support for 1D and higher dimensional transforms using different radices. Factorization for mix‐radices enables our code to target FFTs of near arbitrary length. In systems with multiple graphic cards (GPUs), the library automatically balances the FFT computation thus achieving maximum resource utilization and higher speedup. Based on profiling and micro‐benchmarking of ToPe‐FFT, it is observed that the average speedup of our library for different sizes is 48× faster than the single CPU‐based code using FFTW and 3× faster than NVIDIA's GPU‐based cuFFT library.
Cybersecurity compliance analysis as a service: Requirements specification and application scenarios
Authors: Furfaro Angelo , Gallo Teresa , Garro Alfredo , Saccà Domenico , Tundis Andrea 
Published: August 2017

SummaryCybersecurity compliance analysis is the process of assessing whether the behavior of an IT system or application conforms to the cybersecurity rules and regulations in force. This assessment can be offered as a service by exploiting available cloud technologies, and, indeed, it is one of the services classified by the Cloud Security Alliance (CSA) as part of the security information and event management (SIEM) category of the SecaaS (security as a service) domain. The definition and implementation of this typology of cloud services are challenging activities due to the complexity of both the reference business domain and the compliance analysis services to be provided themselves. The paper exploits a recently proposed requirements methodology, called GOReM (goal‐oriented requirements methodology), to support the conceptualization and subsequent implementation of cybersecurity compliance analysis services. In particular, two different application scenarios regarding compliance analysis of an existing or under development IT system/application are presented and discussed. In both the scenarios, GOReM allows to grasp and understand the many and complex issues to address for providing secure cloud services to worldwide customers, also due to the numerous, different and ever changing legal aspects, which have to be taken into account by service providers.