bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of NaCl on Granulometric Characteristics and Polymorphism in Batch‐Cooling Crystallization of Glycine
Authors: Hrkovac Martina , Kardum Jasna Prlić , Ukrainczyk Neven 
Published: November 2014

AbstractThe effect of NaCl added in different quantities on thermodynamic properties, granulometric characteristics, and structure of glycine in a crystallization process was investigated. Solubilities of α‐ and γ‐polymorphs in the presence of varying amounts of NaCl were analyzed. In order to examine the impact of the additive on granulometric properties of glycine, crystal morphology was examined by observing crystals under a scanning electron microscope. Crystal size distribution was determined by sieve analysis. By X‐ray diffraction analysis, the critical concentration of NaCl at which the structure of glycine changed, could be defined. The purity of obtained polymorphs was confirmed by Fourier transform infrared spectroscopy.
Porous Coordination Polymers of Diverse Topologies Based on a Twisted Tetrapyridylbiaryl: Application as Nucleophilic Catalysts for Acetylation of Phenols
Authors: Seth Saona , Venugopalan Paloth , Moorthy Jarugu Narasimha 
Published: November 2014

AbstractPorous coordination polymers (CPs) with partially uncoordinated pyridyl rings based on rationally designed polypyridyl linkers are appealing from the point of view of their application as nucleophilic catalysts. A D2d‐symmetric tetradentate organic linker L, that is, 2,2′,6,6′‐tetramethoxy‐3,3′,5,5′‐tetrakis(4‐pyridyl)biphenyl, was designed and synthesized for metal‐assisted self‐assembly aimed at porous CPs. Depending on the nature of the metal ion and the counter anion, the ligand L is found to function as a 3‐ or 4‐connecting building block leading to porous CPs of diverse topologies. The reaction of L with Zn(NO3)2 and Cd(NO3)2 yields porous 2 D CPs of “fes” topology, in which the tetrapyridyl linker L serves as a 3‐connecting unit with its free pyridyl rings well exposed into the pores. The functional utility of these porous CPs containing uncoordinated pyridyl rings is demonstrated by employing them as efficient heterogeneous nucleophilic catalysts for acetylation of a number of phenols with varying electronic properties and reactivities.
Electron Transfer‐Initiated Epoxidation and Isomerization Chain Reactions of β‐Caryophyllene
Authors: Steenackers Bart , Campagnol Nicolò , Fransaer Jan , Hermans Ive , De Vos Dirk 
Published: November 2014

AbstractThe abundant sesquiterpene β‐caryophyllene can be epoxidized by molecular oxygen in the absence of any catalyst. In polar aprotic solvents, the reaction proceeds smoothly with epoxide selectivities exceeding 70 %. A mechanistic study has been performed and the possible involvement of free radical, spin inversion, and electron transfer mechanisms is evaluated using experimental and computational methods. The experimental data—including a detailed reaction product analysis, studies on reaction parameters, solvent effects, additives and an electrochemical investigation—all support that the spontaneous epoxidation of β‐caryophyllene constitutes a rare case of unsensitized electron transfer from an olefin to triplet oxygen under mild conditions (80 °C, 1 bar O2). As initiation of the oxygenation reaction, the formation of a caryophyllene‐derived radical cation via electron transfer is proposed. This radical cation reacts with triplet oxygen to a dioxetane via a chain mechanism with chain lengths exceeding 100 under optimized conditions. The dioxetane then acts as an in situ‐formed epoxidizing agent. Under nitrogen atmosphere, the presence of a one‐electron acceptor leads to the selective isomerization of β‐caryophyllene to isocaryophyllene. Observations indicate that this isomerization reaction is a novel and elegant synthetic pathway to isocaryophyllene.
Can CH⋅⋅⋅π Interactions Be Used To Design Single‐Chain Magnets?
Authors: Singh Mukesh Kumar , Rajaraman Gopalan 
Published: November 2014

AbstractThis theoretical study suggests that CH⋅⋅⋅π stacking interactions between monomeric units can be used to design novel single‐chain magnets (SCMs), as the sign of coupling is predictable and such chains inherently yield negative axial anisotropy, a condition often difficult to achieve in conventional SCMs.
Ruthenium(II)‐Catalyzed CH Acyloxylation of Phenols with Removable Auxiliary
Authors: Raghuvanshi Keshav , Rauch Karsten , Ackermann Lutz 
Published: November 2014

AbstractIntermolecular CH acyloxylations of phenols with removable directing groups were accomplished with a versatile ruthenium catalyst. Specifically, a cationic ruthenium(II) complex, formed in situ, enabled the chemoselective CH oxygenations of a broad range of substrates. The catalyst proved tolerant of synthetically valuable functional groups, and the substrate scope included both (hetero)aromatic and, the more challenging, aliphatic carboxylic acids. The proposed reaction mechanism involves a reversible CH ruthenation and an oxidatively induced CO‐bond‐forming reductive elimination.
Oxoanionic Noble Metal Compounds from Fuming Nitric Acid: The Palladium Examples Pd(NO3)2 and Pd(CH3SO3)2
Authors: Bruns Jörn , Klüner Thorsten , Wickleder Mathias S. 
Published: November 2014

AbstractThe oxidation of elemental palladium at 100 °C in a mixture of fuming nitric acid and a pyridine‐SO3 complex leads to the anhydrous nitrate Pd(NO3)2 (monoclinic, P21/n, Z=2, a=469.12(3) pm, b=593.89(3) pm, c=805.72(4) pm, β=105.989(3)°, V=215.79(2) Å3). The Pd2+ ions are in square‐planar coordination with four monodentate nitrate groups which are connected to further palladium atoms, leading to a layer structure. The reaction of elemental palladium with a mixture of fuming nitric acid and methanesulfonic acid at 120 °C leads to single crystals of Pd(CH3SO3)2 (monoclinic, P21/n, Z=2, a=480.44(1) pm, b=1085.53(3) pm, c=739.78(2) pm, β=102.785(1)°, V=376.254(17) Å3). Also in this structure the Pd2+ ions are in square‐planar coordination with four monodentate anions; however, the connection to adjacent palladium atoms leads to a chain‐type structure. The thermal decomposition of the compounds has been investigated by means of DSC/TG measurements. Furthermore, IR and Raman spectra have been recorded, and an assignment of the observed vibrational frequencies has been carried out based on theoretical investigations.
New Polyoxometalates Containing Hybrid Polymers and Their Potential for Nano‐Patterning
Authors: Kalyani Vishwanath , Satyanarayana V. S. V. , Singh Vikram , Pradeep Chullikkattil P. , Ghosh Subrata , Sharma Satinder K. , Gonsalves Kenneth E. 
Published: November 2014

AbstractTwo new polyoxometalate (POM)‐based hybrid monomers (Bu4N)5(H)[P2V3W15O59{(OCH2)3CNHCO(CH3)CCH2}] (2) and (S(CH3)2C6H4OCOC(CH3)=CH2)6[PVMo10O40] (5) were developed by grafting polymerizable organic units covalently or electrostatically onto Wells–Dawson and Keggin‐type clusters and were characterized by analytical and spectroscopic techniques including ESI‐MS and/or single‐crystal X‐ray diffraction analyses. Radical initiated polymerization of 2 and 5 with organic monomers (methacryloyloxy)phenyldimethylsulfonium triflate (MAPDST) and/or methylmethacrylate (MMA) yielded a new series of POM/polymer hybrids that were characterized by 1H, 31P NMR and IR spectroscopic techniques, gel‐permeation chromatography as well as thermal analyses. Preliminary tests were conducted on these POM/polymer hybrids to evaluate their properties as photoresists using electron beam (E‐beam)/extreme ultraviolet (EUV) lithographic techniques. It was observed that the POM/polymer hybrid of 2 with MAPDST exhibited improved sensitivity under EUV lithographic conditions in comparison to the MAPDST homopolymer resist possibly due to the efficient photon harvesting by the POM clusters from the EUV source.
Electrochemical Properties of Yolk–Shell‐Structured Zn–Fe–S Multicomponent Sulfide Materials with a 1:2 Zn/Fe Molar Ratio
Authors: Won Jong Min , Lee Jong‐Heun , Kang Yun Chan 
Published: November 2014

AbstractYolk–shell‐structured Zn–Fe–S multicomponent sulfide materials with a 1:2 Zn/Fe molar ratio were prepared applying a sulfidation process to ZnFe2O4 yolk–shell powders. The Zn–Fe–S powders had mixed sphalerite (Zn,Fe)S and hexagonal FeS crystal structures. The discharge capacities of the Zn–Fe–S powders sulfidated at 350 °C at a constant current density of 500 mA g−1 for the first, second, and fiftieth cycles were 1098, 912, and 913 mA h g−1, respectively. The powders exhibited a high discharge capacity of 602 mA h g−1 even at the high current density of 10 A g−1. The synergistic effect of yolk–shell structure and multicomponent composition improved the electrochemical properties of Zn–Fe–S powders.
Copper‐Catalyzed Difunctionalization of Activated Alkynes by Radical Oxidation–Tandem Cyclization/Dearomatization to Synthesize 3‐Trifluoromethyl Spiro[4.5]trienones
Authors: Hua Hui‐Liang , He Yu‐Tao , Qiu Yi‐Feng , Li Ying‐Xiu , Song Bo , Gao Pin , Song Xian‐Rong , Guo Dong‐Hui , Liu Xue‐Yuan , Liang Yong‐Min 
Published: November 2014

AbstractA copper‐catalyzed difunctionalizing trifluoromethylation of activated alkynes with the cheap reagent sodium trifluoromethanesulfinate (NaSO2CF3 or Langlois’ reagent) has been developed incorporating a tandem cyclization/dearomatization process. This strategy affords a straightforward route to synthesis of 3‐(trifluoromethyl)‐spiro[4.5]trienones, and presents an example of difunctionalization of alkynes for simultaneous formation of two carbon–carbon single bonds and one carbon–oxygen double bond.
Highly Sensitive INHIBIT and XOR Logic Gates Based on ICT and ACQ Emission Switching of a Porphyrin Derivative
Authors: Xu Xiao‐Ling , Lin Fu‐Wen , Xu Wei , Wu Jian , Xu Zhi‐Kang 
Published: November 2014

AbstractFluorescence‐switch‐based logic devices are very sensitive compared with most of the reported devices based on UV/Vis absorption systems. Herein, we demonstrate that a simple molecule, 5,10,15,20‐tetra‐(4‐aminophenyl)porphyrin (TAPP), shows protonation‐induced multiple emission switches through intramolecular charge transfer and/or aggregation‐caused quenching. Highly sensitive INHIBIT and XOR logic gates can be achieved by combining the intermolecular assembly with the intramolecular photoswitching of diprotonated TAPP (TAPPH22+). In addition, molecular simulations have been performed by DFT for a better understanding of the emission‐switching processes.
Asymmetric anti‐Selective Michael Reaction of Imidazole‐Modified Ketones with trans‐β‐Nitroalkenes
Authors: Yang Dongxu , Wang Linqing , Li Dan , Han Fengxia , Zhao Depeng , Wang Rui 
Published: November 2014

AbstractThe successful application of imidazole‐modified ketones in asymmetric anti‐selective Michael reactions with trans‐β‐nitroalkenes is presented by employing a newly developed 3‐bromothiophene‐modified chiral diamine ligand. The corresponding conjugate adduct was submitted to further transformations with Grignard reagents to solve the problem of α‐site selectivity of simple linear ketones. Additionally, the syn‐selective product was obtained by treating the anti‐selective adduct with a simple base. In this way, the site‐specific products for both diastereomers in the asymmetric conjugate addition of simple ketones to nitroalkenes can be obtained.
Formal [4+2] Reaction between 1,3‐Diynes and Pyrroles: Gold(I)‐Catalyzed Indole Synthesis by Double Hydroarylation
Authors: Matsuda Yuka , Naoe Saori , Oishi Shinya , Fujii Nobutaka , Ohno Hiroaki 
Published: November 2014

AbstractIndole synthesis by a gold(I)‐catalyzed intermolecular formal [4+2] reaction between 1,3‐diynes and pyrroles has been developed. This reaction involves the hydroarylation of 1,3‐diynes with pyrroles followed by an intramolecular hydroarylation to give the 4,7‐disubstituted indoles. This reaction can also be applied to the synthesis of carbazoles when indoles are used as the nucleophiles instead of pyrroles.
Intramolecular CN Bond Activation and Ring‐Expansion Reactions of N‐Heterocyclic Carbenes
Authors: Hemberger Patrick , Bodi Andras , Berthel Johannes H. J. , Radius Udo 
Published: November 2014

AbstractIntramolecular ring‐expansion reactions (RER) of the N‐heterocyclic carbene 1,3‐dimethylimidazolin‐2‐ylidene were observed upon vacuum ultraviolet (VUV) photoexcitation. Similarly to RERs reported in the solvent phase, for the reaction of NHCs with main‐group‐element hydrides, hydrogen transfer to the NHC carbon atom is the crucial initial step. In an ionization‐mediated protonation, 1,3‐dimethylimidazolin‐2‐ylidene forms an imidazolium ion, which is the rate‐limiting step on the pathway to two six‐membered ring products, namely, methylpyrimidinium and ‐pyrazinium ions. To unravel the reaction path, we have used imaging photoelectron photoion coincidence spectroscopy with VUV synchrotron radiation, as well as high‐level composite method calculations. Similarities and differences between the mechanism in the gas phase and in the condensed phase are discussed.
Should small papillary thyroid cancer be observed? A population‐based study
Authors: Nilubol Naris , Kebebew Electron 
Published: November 2014

BACKGROUNDSome centers have advocated selecting patients with small papillary thyroid cancer (PTC) to undergo active surveillance without surgical treatment. The objectives of the current study were to analyze thyroid cancer (TC)‐related mortality in a population‐based cohort and to determine the impact of small PTCs (defined as tumors ≤2 cm in greatest dimension) on TC‐related mortality.METHODSData on patients with TC of follicular cell origin from the National Cancer Institute's Surveillance, Epidemiology, and End Results 17 Registries database (1988‐2007) were used to analyze the characteristics of PTCs ≤2 cm in patients who died from TC‐related causes. The effects of clinical features on disease‐specific survival were analyzed.RESULTSOver the 20‐year study period, the rate of TC‐related mortality was 2.8% (n = 1753 of 61,523 patients). Of the patients who died from TC‐related causes, 38% had PTC, 10% had follicular TC, and 31.3% had anaplastic TC. PTCs ≤2 cm accounted for 12.3% of TC‐related mortalities. Compared with patients who did not experience TC‐related mortality from PTCs ≤2 cm, there were significantly higher rates of men (30% vs 17%;P < .01), patients aged ≥45 years (92% vs 52%;P < .01), tumors measuring >1 cm (59% vs 46%;P < .01), extrathyroid extension (41% vs 11%;P < .01), lymph node metastases (77% vs 28%;P < .01), and distant metastases (31% vs 1%;P < .01) among the patients who died from PTCs ≤2 cm. Independent risk factors for death from PTCs ≤2 cm included age ≥45 years, lymph node and distant metastases, extrathyroid extension, and undergoing less than thyroid lobectomy.CONCLUSIONSBecause 12.3% of patients who experienced TC‐related deaths had PTCs ≤2 cm despite undergoing thyroidectomy, the current results indicate that nonoperative management for patients who have PTCs ≤2 cm should be used with caution. Patients aged ≥45 years with PTCs ≤2 cm should undergo thyroidectomy.Cancer 2015;121:1017–1024.©2014 American Cancer Society.
Sodium channel β1 subunit localizes to axon initial segments of excitatory and inhibitory neurons and shows regional heterogeneity in mouse brain
Authors: Wimmer Verena C. , Harty Rosemary C. , Richards Kay L. , Phillips A. Marie , Miyazaki Haruko , Nukina Nobuyuki , Petrou Steven 
Published: November 2014

ABSTRACTThe β1 subunit of voltage‐gated sodium channels, Navβ1, plays multiple roles in neurons spanning electrophysiological modulation of sodium channel α subunits to cell adhesion and neurite outgrowth. This study used immunohistochemistry to investigate Navβ1 subneuronal and regional expression. Navβ1 was enriched at axon initial segments (AIS) and nodes of Ranvier. Navβ1 expression at the AIS was detected throughout the brain, predominantly in the hippocampus, cortex, and cerebellum. Despite expression of Navβ1 in both excitatory and inhibitory AIS, it displayed a marked and fine‐grained heterogeneity of expression. Such heterogeneity could have important implications for the tuning of single neuronal and regional excitability, especially in view of the fact that Navβ1 coexpressed with Nav1.1, Nav1.2, and Nav1.6 subunits. The disruption of Navβ1 AIS expression by a human epilepsy‐causing C121W genetic mutation in Navβ1 was also investigated using a mouse model. AIS expression of Navβ1 was reduced by approximately 50% in mice heterozygous for the C121W mutation and was abolished in homozygotes, suggesting that loss of Navα subunit modulation by Navβ1 contributes to the mechanism of epileptogenesis in these animals as well as in patients. J. Comp. Neurol. 523:814–830, 2015. © 2015 Wiley Periodicals, Inc.
Parallelizing the execution of native data mining algorithms for computational biology
Authors: Coro Gianpaolo , Candela Leonardo , Pagano Pasquale , Italiano Angela , Liccardo Loredana 
Published: November 2014

SummaryData mining is being increasingly used in biology. Biologists are adopting prototyping languages, like R and Matlab, to facilitate the application of data mining algorithms to their data. As a result, their scripts are becoming increasingly complex and also require frequent updates. Application to large datasets becomes impractical and the time‐to‐paper increases. Furthermore, even if there are various systems that can be used to efficiently process large datasets, for example, using Cloud and High Performance Computing, they usually require procedures to be translated into specific languages or to be adapted to a certain computing platform. Such modifications can speed up the processing, but translation is not automatic, especially in complex cases, and can require a large amount of programming effort and accurate validation. In this paper, we propose an approach to parallelize data mining procedures in the form of compiled software or R scripts developed by biology communities of practice. Our approach requires minimal alteration of the original code. In many cases, there is no need for code modification. Furthermore, it allows for fast updating when a new version is ready. We clarify the constraints and the benefits of our method and report a practical use case to demonstrate such benefits compared with a standard execution. Our approach relies on a distributed network of web services and ultimately exposes the algorithms as‐a‐Service, to be invoked by remote thin clients. Copyright © 2014 John Wiley & Sons, Ltd.
Divide‐and‐conquer approach for solving singular value decomposition based on MapReduce
Authors: Zhao Shuoyi , Li Ruixuan , Tian Wenlong , Xiao Weijun , Dong Xinhua , Liao Dongjie , Khan Samee U. , Li Keqin 
Published: November 2014

SummarySingular value decomposition (SVD) shows strong vitality in the area of information analysis and has significant application value in most of the scientific big data fields. However, with the rapid development of Internet, the information online reveals fast growing trend. For a large‐scale matrix, applying SVD computation directly is both time consuming and memory demanding. There are many works available to speed up the computation of SVD based on the message passing interface model. However, to deal with large‐scale data processing, a MapReduce model has many advantages over a message passing interface model, such as fault tolerance, load balancing and simplicity. For a MapReduce environment, existing approaches only focus on low rank SVD approximation and tall‐and‐skinny matrix SVD computation, and there are no implementations of full rank SVD computation. In this paper, we propose a MapReduce‐based implementation for solving divide‐and‐conquer SVD algorithm. To achieve high performance, we design a two‐stage task scheduling strategy based on the mathematical characteristics of divide‐and‐conquer SVD algorithm. To further strengthen the performance, we propose a row‐index‐based divide algorithm, a pipelined task scheduling method, and revised block matrix multiplication in MapReduce framework. Experimental result shows the efficiency of our algorithm. Our implementation can accommodate full rank SVD computation of large‐scale matrix very efficiently. Copyright © 2014 John Wiley & Sons, Ltd.
Analyzing runtime adaptability of collaboration patterns
Authors: Dorn Christoph , Taylor Richard N. 
Published: November 2014

SummaryThe recent two decades have witnessed the emergence of large‐scale, interaction‐intensive systems. A system's provided user‐centric communication and coordination mechanisms have a significant impact on its runtime management. Beyond a certain size, manual monitoring and management are no longer feasible. Hence, it is highly important for a system designer to becoming aware of the most suitable interaction mechanisms and their implications on system adaptability. Specifically, a system designer requires knowledge on what adaptation primitives are available, whether these are system‐driven or user‐driven, how long they will take, what impact do they have on collaboration state, and under what conditions they can be enacted. These aspects vary considerably across collaboration patterns.In this paper, we investigate a collaboration structure's adaptability based on behavior, asynchrony, state, and execution context. We subsequently discuss seven distinctively different collaboration patterns in terms of those aspects. Based on a motivating scenario, we ultimately demonstrate how these patterns and insights into their inherent adaptability may guide design decision impact and trade‐off analysis. Copyright © 2014 John Wiley & Sons, Ltd.
Multi‐tenancy authorization models for collaborative cloud services
Authors: Tang Bo , Sandhu Ravi , Li Qi 
Published: November 2014

SummaryThe cloud service model intrinsically caters to multiple tenants, most obviously not only in public clouds but also in private clouds for large organizations. Currently, most cloud service providers isolate user activities and data within a single tenant boundary with no or minimum cross‐tenant interaction. It is anticipated that this situation will evolve soon to foster cross‐tenant collaboration supported by Authorization as a Service. At present, there is no widely accepted model for cross‐tenant authorization. Recently, Calero et al. informally presented a multi‐tenancy authorization system (MTAS), which extends the well‐known role‐based access control model by building trust relations among collaborating tenants. In this paper, we formalize this MTAS model and propose extensions for finer‐grained cross‐tenant trust. We also develop an administration model for MTAS. We demonstrate the utility and practical feasibility of MTAS by means of an example policy specification in extensible access control markup language. To further test the metrics of the model, we develop a prototype system and conduct experiments on it. The result shows that the prototype has 12‐ms policy decision overhead on average and is scalable. We anticipate that researchers will develop additional multi‐tenant authorization models before eventual consolidation and convergence to standard industry practice. Copyright © 2014 John Wiley & Sons, Ltd.