bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expedient Synthesis of N‐Methyl‐ and N‐Alkylamines by Reductive Amination using Reusable Cobalt Oxide Nanoparticles
Authors: Senthamarai Thirusangumurugan , Murugesan Kathiravan , Natte Kishore , Kalevaru Narayana V. , Neumann Helfried , Kamer Paul C. J. , Jagadeesh Rajenahally V. 
Published: November 2017

AbstractN‐Methyl‐ and N‐alkylamines represent important fine and bulk chemicals that are extensively used in both academic research and industrial production. Notably, these structural motifs are found in a large number of life‐science molecules and play vital roles in regulating their activities. Therefore, the development of convenient and cost‐effective methods for the synthesis and functionalization of amines by using earth‐abundant metal‐based catalysts is of scientific interest. In this regard, herein we report an expedient reductive amination process for the selective synthesis of N‐methylated and N‐alkylated amines by using nitrogen‐doped, graphene‐activated nanoscale Co3O4‐based catalysts. Starting from inexpensive and easily accessible nitroarenes or amines and aqueous formaldehyde or aldehydes in the presence of formic acid, this cost‐efficient reductive amination protocol allows the synthesis of various N‐methyl‐ and N‐alkylamines, amino acid derivatives, and existing drug molecules.
Oxidation of Polynuclear Aromatic Hydrocarbons using Ruthenium‐Ion‐Catalyzed Oxidation: The Role of Aromatic Ring Number in Reaction Kinetics and Product Distribution
Authors: Nowicka Ewa , Clarke Tomos J. , Sankar Meenakshisundaram , Jenkins Robert L. , Knight David W. , Golunski Stanislaw , Hutchings Graham J. , Willock David J. , Francisco Manuel , Taylor Stuart H. 
Published: November 2017

AbstractOxidation of aromatic hydrocarbons with differing numbers of fused aromatic rings (2–5), have been studied in two solvent environments (monophasic and biphasic) using ruthenium‐ion‐catalyzed oxidation (RICO). RICO reduces the aromaticity of the polyaromatic core of the molecule in a controlled manner by selective oxidative ring opening. Moreover, the nature of the solvent system determines the product type and distribution, for molecules with more than two aromatic rings. Competitive oxidation between substrates with different numbers of aromatic rings has been studied in detail. It was found that the rate of polyaromatic hydrocarbon oxidation increases with the number of fused aromatic rings. A similar trend was also identified for alkylated aromatic hydrocarbons. The proof‐of‐concept investigation provides new insight into selective oxidation chemistry for upgrading of polyaromatic molecules.
Potential Therapeutic Applications of MnSODs and SOD‐Mimetics
Authors: Bonetta Rosalin 
Published: November 2017

AbstractNatural as well as synthetic antioxidants are constantly being investigated for their efficiency in combatting the effects of oxidative stress, which appears to be the responsible cause of several diseases, including cancer, central nervous system disorders, ischaemia‐reperfusion disorders, cardiovascular conditions, and diabetes. Superoxide dismutases (SODs) constitute the ubiquitous antioxidant defences against oxidative stress that underlies numerous pathological conditions. Therefore, the development of therapeutics aimed at either delivering MnSOD more effectively to target tissues in the body in the form of MnSOD gene therapy, or the synthesis of molecules that mimic the activity of superoxide dismutase is constantly being explored. Classes that have been developed as SOD mimetics include the Mn‐metalloporphyrins, Mn‐cyclic polyamines, Mn‐salen complexes, MnPLED derivatives as well as the nitroxides. Thus far, SOD mimetics have shown remarkable efficacy in several animal models suffering from oxidative stress injuries. A promising approach for the future of SOD and SOD mimic therapeutics appears to involve combination treatment of the antioxidants with radiotherapy or chemotherapy.
Redox‐Dependent Metal−Metal Bonding in Trinuclear Metal Chains: Probing the Transition from Covalent Bonding to Exchange Coupling
Authors: Obies Mohammed , Perkins Nicholas R. , Arcisauskaite Vaida , Heath Graham A. , Edwards Alison J. , McGrady John E. 
Published: November 2017

AbstractThe synthesis and physical properties of two new cationic tri‐metallic chains, [(PEt3)3RuCl3M′Cl3Ru(PEt3)3]1+, M′=Rh and Ir are reported. These are isostructural with a previously reported 17‐electron all‐ruthenium analogue, but replacing a d5 RuIII ion in the central position with d6 RhIII/IrIII has a significant impact on the nature of the metal‐metal interactions. All three materials have been characterized electrochemically at the 18‐, 17‐ and 16‐electron levels. X‐ray crystallography and spectroelectrochemistry, complemented by electronic structure analysis at the DFT and CASPT2 levels, indicate that whilst the presence of a RuIII ion in the center of the chain allows multi‐center covalent bonding to develop, a closed‐shell RhIII/IrIII ion pushes the system towards the exchange‐coupled limit, where the outer Ru centers are only weakly interacting. This family of three isostructural compounds reveals how changes in metal composition can have subtle effects on physical properties of systems that lie close to the localized/delocalized borderline.
Control of Enantioselectivity in Rhodium(I) Catalysis by Planar Chiral Dibenzo[a,e]cyclooctatetraenes
Authors: Melcher Michaela‐Christina , Ivšić Trpimir , Olagnon Charlotte , Tenten Christina , Lützen Arne , Strand Daniel 
Published: November 2017

AbstractPlanar chiral 5,11‐disubstiuted dibenzo[a,e]cyclo‐octatetraenes (dbCOTs) have been developed as the first useful chiral homologs to dbCOT‐ligands for asymmetric applications. Methods enabling the preparation of such compounds on a gram‐scale in enantiomerically pure form are described. Evaluated as ligands in rhodium(I)‐catalyzed 1,4‐ and 1,2‐arylation reactions, tertiary and quarternary stereogenic centers were formed with excellent yields and selectivities of up to >99 % ee. A catalytic asymmetric synthesis of a key cyclization precursor to (−)‐penifulvin A highlights the system in an applied context.
Synthesis of Fucosylated Chondroitin Sulfate Glycoclusters: A Robust Route to New Anticoagulant Agents
Authors: Zhang Xiao , Yao Wang , Xu Xiaojiang , Sun Huifang , Zhao Jinhua , Meng Xiangbao , Wu Mingyi , Li Zhongjun 
Published: November 2017

AbstractFucosylated chondroitin sulfate (FuCS) is a structurally distinct glycosaminoglycan with excellent anticoagulant activity. Studies show that FuCS and its depolymerized fragments exhibit a different anticoagulant mechanism from that of heparin derivatives, with decreased risks of adverse effects and bleeding. However, further exploitation has been hindered by the scarcity of structurally defined oligosaccharides. Herein, facile method is reported for the synthesis of the repeating trisaccharide unit of FuCS based on the degradation of chondroitin sulfate polymers. A series of simplified FuCS glycomimetics that have highly tunable structures, controllable branches, and defined sulfation motifs were generated by copper‐catalyzed alkyne–azide cycloaddition. Remarkable improvement in activated partial thromboplastin time (APTT) assay activities was observed as the branches increased, but no significant influences were observed for prothrombin time (PT) and thrombin time (TT) assay activities. Further FXase inhibition tests suggested that glycoclusters 33 b–40 b selectively inhibited intrinsic anticoagulant activities, but had little effect on the extrinsic and common coagulation pathways. Notably, glycoclusters with the 2,4‐di‐O‐sulfated fucosyl residue displayed the most potency, which was in consistent with that of natural polysaccharides. These FuCS clusters demonstrated potency to mimic linear glycosaminoglycans and offer a new framework for the development of novel anticoagulant agents.
Dichromatic Photocatalytic Substitutions of Aryl Halides with a Small Organic Dye
Authors: Neumeier Michael , Sampedro Diego , Májek Michal , de la Peña O'Shea Víctor A. , Jacobi von Wangelin Axel , Pérez‐Ruiz Raúl 
Published: November 2017

AbstractPhotocatalytic bond activations are generally limited by the photon energy and the efficiency of energy and electron transfer processes. Direct two‐photon processes provide sufficient energy but the ultra‐short lifetimes of the excited states prohibit chemical reactions. The commercial dye 9,10‐dicyanoanthracene enabled photocatalytic aromatic substitutions of non‐activated aryl halides. This reaction operates under VIS‐irradiation via sequential photonic, electronic, and photonic activation of the simple organic dye. The resultant highly reducing excited photocatalyst anion readily effected C−H, C−C, C−P, C−S, and C−B bond formations. Detailed synthetic, spectroscopic, and theoretical studies support a biphotonic catalytic mechanism.
Numerical simulation of a semi‐industrial scale CFB riser using coarse‐grained DDPM‐EMMS modelling
Authors: Adnan Muhammad , Zhang Nan , Sun Fangfang , Wang Wei 
Published: November 2017

AbstractIn this work, a coarse‐grained Dense Discrete Phase Model (DDPM) coupled with the Energy‐Minimization Multi‐Scale (EMMS) drag, was used to simulate the hydrodynamics of a 3D semi‐industrial scale Circulating Fluidized Bed (CFB) with Geldart A particles. The effect of particle numbers in a parcel, an important parameter in a coarse‐grained approach, was investigated. It was found that when parcel diameter falls into the size range of clusters, simulation results are insensitive to particle number in a parcel and generally agree with the experimental data. Further, a comparison between DDPM and Eulerian Two‐Fluid Modelling (TFM) approaches was investigated, both coupled with EMMS and conventional homogenous drag. The simulation results suggested that the effect of meso‐scale structures on drag force needs to be considered in both modelling approaches.
Diagnostic challenges and problem cases in salivary gland cytology: A 20‐year experience
Authors: Salehi Sajad , Maleki Zahra 
Published: November 2017

BACKGROUNDFine‐needle aspiration (FNA) is routinely performed to evaluate salivary gland lesions, and provides valuable information regarding the cytomorphologic features of the lesions. Occasionally, there are overlaps between benign and malignant conditions due to heterogeneity of the cell types, metaplastic changes, and sampling issues. Herein, the authors present a retrospective study of diagnostic pitfalls in salivary gland cytology and the simulating conditions.METHODSA 20‐year retrospective review (1995‐2015) of medical records was performed searching for the cytology reports of patients who underwent FNA of the salivary gland with the words “amendment” or “revision.” Medical records of the revised cases were reviewed for the subsequent surgical follow‐up. All cases with a diagnostic discrepancy between the primary cytologic diagnosis and the final histology diagnosis were included in the current study. The histologic diagnosis was considered the gold standard.RESULTSA total of 19 cases were included in the current study. The cases were divided into 7 categories based on their cytologic diagnoses: 1) nondiagnostic (1 case); 2) benign, nonneoplastic lesion (2 cases); 3) benign salivary gland neoplasm (2 cases); 4) salivary gland neoplasm (4 cases); 5) epithelial neoplasm, not otherwise specified (1 case); 6) markedly atypical cells suspicious for a malignant neoplasm (1 case); and 7) malignant neoplasms (8 cases).CONCLUSIONSThe interpretation of salivary gland FNA can be influenced by several factors including prominent metaplasia, focal atypia, cystic changes, variable cellular components within the lesions, scant cellularity, variants of neoplasms, and a prior history of malignancy. Multiple passes representing the entire mass, imaging findings, and familiarity with salivary gland cytomorphology may improve the diagnostic accuracy. Cancer Cytopathol 2018;126:101‐11. © 2017 American Cancer Society.
Performance comparison between Hadoop and Spark frameworks using HiBench benchmarks
Authors: Samadi Yassir , Zbakh Mostapha , Tadonki Claude 
Published: November 2017

SummaryBig Data has become one of the major areas of research for cloud service providers due to a large amount of data produced every day and the inefficiency of traditional algorithms and technologies to handle these large amounts of data. Big Data with its characteristics such as volume, variety, and veracity (3V) requires efficient technologies to process in real time. To solve this problem and to process and analyze this vast amount of data, there are many powerful tools like Hadoop and Spark, which are mainly used in the context of Big Data. They work following the principles of parallel computing. The challenge is to specify which Big Data's tool is better depending on the processing context. In this paper, we present and discuss a performance comparison between two popular Big Data frameworks deployed on virtual machines. Hadoop MapReduce and Apache Spark are used to efficiently process a vast amount of data in parallel and distributed mode on large clusters, and both of them suit for Big Data processing. We also present the execution results of Apache Hadoop in Amazon EC2, a major cloud computing environment. To compare the performance of these two frameworks, we use HiBench benchmark suite, which is an experimental approach for measuring the effectiveness of any computer system. The comparison is made based on three criteria: execution time, throughput, and speedup. We test Wordcount workload with different data sizes for more accurate results. Our experimental results show that the performance of these frameworks varies significantly based on the use case implementation. Furthermore, from our results we draw the conclusion that Spark is more efficient than Hadoop to deal with a large amount of data in major cases. However, Spark requires higher memory allocation, since it loads the data to be processed into memory and keeps them in caches for a while, just like standard databases. So the choice depends on performance level and memory constraints.
Understanding the Reactive Adsorption of H2S and CO2 in Sodium‐Exchanged Zeolites
Authors: Fetisov Evgenii O. , Shah Mansi S. , Knight Christopher , Tsapatsis Michael , Siepmann J. Ilja 
Published: November 2017

AbstractPurifying sour natural gas streams containing hydrogen sulfide and carbon dioxide has been a long‐standing environmental and economic challenge. In the presence of cation‐exchanged zeolites, these two acid gases can react to form carbonyl sulfide and water (H2S+CO2⇌H2O+COS), but this reaction is rarely accounted for. In this work, we carry out reactive first‐principles Monte Carlo (RxFPMC) simulations for mixtures of H2S and CO2 in all‐silica and Na‐exchanged forms of zeolite beta to understand the governing principles driving the enhanced conversion. The RxFPMC simulations show that the presence of Na+ cations can change the equilibrium constant by several orders of magnitude compared to the gas phase or in all‐silica beta. The shift in the reaction equilibrium is caused by very strong interactions of H2O with Na+ that reduce the reaction enthalpy by about 20 kJ mol−1. The simulations also demonstrate that the siting of Al atoms in the framework plays an important role. The RxFPMC method presented here is applicable to any chemical conversion in any confined environment, where strong interactions of guest molecules with the host framework and high activation energies limit the use of other computational approaches to study reaction equilibria.
Synthesis and Properties of Open Fullerenes Encapsulating Ammonia and Methane
Authors: Bloodworth Sally , Gräsvik John , Alom Shamim , Kouřil Karel , Elliott Stuart J. , Wells Neil J. , Horsewill Anthony J. , Mamone Salvatore , Jiménez‐Ruiz Mónica , Rols Stéphane , Nagel Urmas , Rõõm Toomas , Levitt Malcolm H. , Whitby Richard J. 
Published: November 2017

AbstractWe describe the synthesis and characterisation of open fullerene (1) and its reduced form (2) in which CH4 and NH3 are encapsulated, respectively. The 1H NMR resonance of endohedral NH3 is broadened by scalar coupling to the quadrupolar 14N nucleus, which relaxes rapidly. This broadening is absent for small satellite peaks, which are attributed to natural abundance 15N. The influence of the scalar relaxation mechanism on the linewidth of the 1H ammonia resonance is probed by variable temperature NMR. A rotational correlation time of τc=1.5 ps. is determined for endohedral NH3, and of τc=57±5 ps. for the open fullerene, indicating free rotation of the encapsulated molecule. IR spectroscopy of NH3@2 at 5 K identifies three vibrations of NH3 (ν1, ν3 and ν4) redshifted in comparison with free NH3, and temperature dependence of the IR peak intensity indicates the presence of a large number of excited translational/ rotational states. Variable temperature 1H NMR spectra indicate that endohedral CH4 is also able to rotate freely at 223 K, on the NMR timescale. Inelastic neutron scattering (INS) spectra of CH4@1 show both rotational and translational modes of CH4. Energy of the first excited rotational state (J=1) of CH4@1 is significantly lower than that of free CH4.
Gut microbiota and body composition in anorexia nervosa inpatients in comparison to athletes, overweight, obese, and normal weight controls
Authors: Mörkl Sabrina , Lackner Sonja , Müller Wolfram , Gorkiewicz Gregor , Kashofer Karl , Oberascher Andreas , Painold Annamaria , Holl Anna , Holzer Peter , Meinitzer Andreas , Mangge Harald , Holasek Sandra 
Published: November 2017

AbstractObjectivesAnorexia nervosa (AN) is a heterogeneous eating disorder associated with alterations of body structure and the gut microbiome. We aimed to investigate the gut microbiota composition of a large female cohort including different BMI groups and activity levels along with body composition parameters.Method106 female participants were included in this cross‐sectional study: AN patients (n = 18), athletes (n = 20), normal weight (n = 26), overweight (n = 22), and obese women (n = 20). DNA was extracted from stool samples and subjected to 16S rRNA gene analysis. The software Quantitative Insights Into Microbial Ecology (QIIME) was used to analyze data. Additionally, we performed anthropometric assessments, ultrasound measurements of subcutaneous adipose tissue thickness, bioimpedance analysis, administered depression inventories, and ascertained laboratory parameters and dietary intakes.ResultsAlpha diversity was particularly lower in AN patients and obese participants compared to other groups, while athletes showed highest alpha diversity. Several categories significantly associated with community structure were identified: body fat parameters, serum lipids, CRP, depression scales and smoking. Comparative analysis revealed Coriobacteriaceae as the only enriched phylotype in AN compared to other entities (LDA score >3.5).DiscussionThis study provides further evidence of intestinal dysbiosis in AN and sheds light on characteristics of the gut microbiome in different BMI and physical activity groups. These insights point to new modulation possibilities of the gut microbiota which could improve the standard therapy of AN.
Hemiparasites can transmit indirect effects from their host plants to herbivores
Authors: Haan Nathan L. , Bakker Jonathan D. , Bowers M. Deane 
Published: November 2017

AbstractParasitic plants can serve as critical intermediaries between their hosts and other organisms; however these relationships are not well understood. To investigate the relative importance of plant traits in such interactions, we studied the role of the root hemiparasite,Castilleja levisecta(Orobanchaceae), as a mediator of interactions between the host plants it parasitizes and the lepidopteran herbivoreEuphydryas editha(Nymphalidae), whose caterpillars feed onCastillejaand sequester iridoid glycosides from it. We tested whether the hemiparasite's size, leaf N concentration, and iridoid glycoside concentrations were influenced by the identity of its host plant, and then whether these traits influenced outcomes for the herbivore. We found that the hemiparasite's size and leaf N depended on the host it parasitized, and these traits in turn affected outcomes forE. editha. Specifically,Euphydryas edithasurvival increased with hemiparasite size and caterpillar mass increased with leaf N; caterpillars with greater mass were more likely to survive during diapause. We also found preliminary evidence that host identity influenced iridoid glycoside sequestration by the herbivore. Mean iridoid glycoside concentrations in caterpillars ranged from 1–12% depending on the host being parasitized byCastilleja. This study demonstrates that root parasitism can result in strong indirect effects on higher trophic levels, influencing organisms’ survival, growth, and chemical interactions.
Conductance‐based profiling of nanopores: Accommodating fabrication irregularities
Authors: Bandara Y. M. N. D. Y. , Nichols Jonathan W. , Iroshika Karawdeniya Buddini , Dwyer Jason R. 
Published: November 2017

AbstractSolid‐state nanopores are nanoscale channels through otherwise impermeable membranes. Single molecules or particles can be passed through electrolyte‐filled nanopores by, e.g. electrophoresis, and then detected through the resulting physical displacement of ions within the nanopore. Nanopore size, shape, and surface chemistry must be carefully controlled, and on extremely challenging <10 nm‐length scales. We previously developed a framework to characterize nanopores from the time‐dependent changes in their conductance as they are being formed through solution‐phase nanofabrication processes with the appeal of ease and accessibility. We revisited this simulation work, confirmed the suitability of the basic conductance equation using the results of time‐dependent experimental conductance measurements during nanopore fabrication by Yanagi et al., and then deliberately relaxed the model constraints to allow for (i) the presence of defects; and (ii) the formation of two small pores instead of one larger one. Our simulations demonstrated that the time‐dependent conductance formalism supports the detection and characterization of defects, as well as the determination of pore number, but with implementation performance depending on the measurement context and results. In some cases, the ability to discriminate numerically between the correct and incorrect nanopore profiles was slight, but with accompanying differences in candidate nanopore dimensions that could yield to post‐fabrication conductance profiling, or be used as convenient uncertainty bounds. Time‐dependent nanopore conductance thus offers insight into nanopore structure and function, even in the presence of fabrication defects.