bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantifying brain volumes for Multiple Sclerosis patients follow‐up in clinical practice – comparison of 1.5 and 3 Tesla magnetic resonance imaging
Authors: Lysandropoulos Andreas P. , Absil Julie , Metens Thierry , Mavroudakis Nicolas , Guisset François , Van Vlierberghe Eline , Smeets Dirk , David Philippe , Maertens Anke , Van Hecke Wim 
Published: January 2016

AbstractIntroductionThere is emerging evidence that brain atrophy is a part of the pathophysiology of Multiple Sclerosis (MS) and correlates with several clinical outcomes of the disease, both physical and cognitive. Consequently, brain atrophy is becoming an important parameter in patients' follow‐up. Since in clinical practice both 1.5Tesla (T) and 3T magnetic resonance imaging (MRI) systems are used for MS patients follow‐up, questions arise regarding compatibility and a possible need for standardization.MethodsTherefore, in this study 18 MS patients were scanned on the same day on a 1.5T and a 3T scanner. For each scanner, a 3D T1 and a 3D FLAIR were acquired. As no atrophy is expected within 1 day, these datasets can be used to evaluate the median percentage error of the brain volume measurement for gray matter (GM) volume and parenchymal volume (PV) between 1.5T and 3T scanners. The results are obtained with MSmetrix, which is developed especially for use in the MS clinical care path, and compared to Siena (FSL), a widely used software for research purposes.ResultsThe MSmetrix median percentage error of the brain volume measurement between a 1.5T and a 3T scanner is 0.52% for GM and 0.35% for PV. For Siena this error equals 2.99%. When data of the same scanner are compared, the error is in the order of 0.06–0.08% for both MSmetrix and Siena.ConclusionsMSmetrix appears robust on both the 1.5T and 3T systems and the measurement error becomes an order of magnitude higher between scanners with different field strength.
Restabilization of Acrylic Acid in Isoperibolic Reactors
Authors: Pfeifer Christian A. , Vizer Artur , Vogel Herbert 
Published: January 2016

AbstractThe spontaneous polymerization, i.e, runaway, of acrylic acid during storage is a serious problem which may endanger life and facilities. In respond to a starting polymerization, effective emergency measures are necessary. For these investigations, a polytropic reactor setup, namely, an isoperibolic reactor is introduced to offer a rational access to restabilization studies. Furthermore, safety diagrams are created where the used amount of stabilizer is plotted against the polymerization progress in terms of the rising temperature. Such diagrams display the minimum required amount of the shortstopper (RESTAB™) for terminating a runaway polymerization. The suitability of the reaction setup is investigated using unstabilized acrylic acid.
Bismuth Nanoparticles Embedded in Carbon Spheres as Anode Materials for Sodium/Lithium‐Ion Batteries
Authors: Yang Fuhua , Yu Fan , Zhang Zhian , Zhang Kai , Lai Yanqing , Li Jie 
Published: January 2016

AbstractSodium‐ion batteries (SIBs) are regarded as an attractive alternative to lithium‐ion batteries (LIBs) for large‐scale commercial applications, because of the abundant terrestrial reserves of sodium. Exporting suitable anode materials is the key to the development of SIBs and LIBs. In this contribution, we report on the fabrication of Bi@C microspheres using aerosol spray pyrolysis technique. When used as SIBs anode materials, the Bi@C microsphere delivered a high capacity of 123.5 mAh g−1 after 100 cycles at 100 mA g−1. The rate performance is also impressive (specific capacities of 299, 252, 192, 141, and 90 mAh g−1 are obtained under current densities of 0.1, 0.2, 0.5, 1, and 2 A g−1, respectively). Furthermore, the Bi@C microsphere also proved to be suitable LIB anode materials. The excellent electrochemical performance for both SIBs and LIBs can attributed to the Bi@C microsphere structure with Bi nanoparticles uniformly dispersed in carbon spheres.
Peroxide Coordination of Tellurium in Aqueous Solutions
Authors: Mikhaylov Alexey A. , Medvedev Alexander G. , Churakov Andrei V. , Grishanov Dmitry A. , Prikhodchenko Petr V. , Lev Ovadia 
Published: January 2016

AbstractTellurium–peroxo complexes in aqueous solutions have never been reported. In this work, ammonium peroxotellurates (NH4)4Te2(μ‐OO)2(μ‐O)O4(OH)2 (1) and (NH4)5Te2(μ‐OO)2(μ‐O)O5(OH)⋅1.28 H2O⋅0.72 H2O2 (2) were isolated from 5 % hydrogen peroxide aqueous solutions of ammonium tellurate and characterized by single‐crystal and powder X‐ray diffraction analysis, by Raman spectroscopy and thermal analysis. The crystal structure of 1 comprises ammonium cations and a symmetric binuclear peroxotellurate anion [Te2(μ‐OO)2(μ‐O)O4(OH)2]4−. The structure of 2 consists of an unsymmetrical [Te2(μ‐OO)2(μ‐O)O5(OH)]5− anion, ammonium cations, hydrogen peroxide, and water. Peroxotellurate anions in both 1 and 2 contain a binuclear Te2(μ‐OO)2(μ‐O) fragment with one μ‐oxo‐ and two μ‐peroxo bridging groups. 125Te NMR spectroscopic analysis shows that the peroxo bridged bitellurate anions are the dominant species in solution, with 3–40 %wt H2O2 and for pH values above 9. DFT calculations of the peroxotellurate anion confirm its higher thermodynamic stability compared with those of the oxotellurate analogues. This is the first direct evidence for tellurium–peroxide coordination in any aqueous system and the first report of inorganic tellurium–peroxo complexes. General features common to all reported p‐block element peroxides could be discerned by the characterization of aqueous and crystalline peroxotellurates.
The Chemical Bond in C2
Authors: Hermann Markus , Frenking Gernot 
Published: January 2016

AbstractQuantum chemical calculations using the complete active space of the valence orbitals have been carried out for HnCCHn (n=0–3) and N2. The quadratic force constants and the stretching potentials of HnCCHn have been calculated at the CASSCF/cc‐pVTZ level. The bond dissociation energies of the C−C bonds of C2 and HC≡CH were computed using explicitly correlated CASPT2‐F12/cc‐pVTZ‐F12 wave functions. The bond dissociation energies and the force constants suggest that C2 has a weaker C−C bond than acetylene. The analysis of the CASSCF wavefunctions in conjunction with the effective bond orders of the multiple bonds shows that there are four bonding components in C2, while there are only three in acetylene and in N2. The bonding components in C2 consist of two weakly bonding σ bonds and two electron‐sharing π bonds. The bonding situation in C2 can be described with the σ bonds in Be2 that are enforced by two π bonds. There is no single Lewis structure that adequately depicts the bonding situation in C2. The assignment of quadruple bonding in C2 is misleading, because the bond is weaker than the triple bond in HC≡CH.
Hydrazine‐Assisted Liquid Exfoliation of MoS2 for Catalytic Hydrodeoxygenation of 4‐Methylphenol
Authors: Liu Guoliang , Ma Hualong , Teixeira Ivo , Sun Zhenyu , Xia Qineng , Hong Xinlin , Tsang Shik Chi Edman 
Published: January 2016

AbstractA simple but effective method to exfoliate bulk MoS2 in a range of solvents is presented for the preparation of colloid flakes consisted of one to a few molecular layers by application of ultrasonic treatment in N2H4. Their high yield in solution and exposure of more active surface sites allows the synthesis of corresponding solid catalysts with remarkably high activity in hydrodeoxygenation of 4‐methylphenol and this method can also be applied to other two dimensional materials.
Seed‐Mediated Growth of Silver Nanocubes in Aqueous Solution with Tunable Size and Their Conversion to Au Nanocages with Efficient Photothermal Property
Authors: Lin Zhen‐Wen , Tsao Yu‐Chi , Yang Min‐Yi , Huang Michael H. 
Published: January 2016

AbstractTwo seed‐mediated approaches for the growth of silver nanocubes in aqueous solution have been developed. Addition of a silver‐seed solution to a mixture of cetyltrimethylammonium chloride (CTAC), silver trifluoroacetate, and ascorbic acid and heating the solution at 60 °C for 1.5 h produces uniform Ag nanocubes with tunable sizes from 23 to 60 nm by simply adjusting the volume of silver‐seed solution introduced. Alternatively, the silver‐seed solution can be injected into a mixture of cetyltrimethylammonium bromide (CTAB), silver nitrate, copper sulfate, and ascorbic acid and heated to 80 °C for 2 h to generate 46 nm silver nanocubes. Plate‐like Ag nanocrystals exposing {111} surfaces can be synthesized by reducing Ag(NH3)2+ with ascorbic acid in a CTAC solution. Relatively large Ag nanocubes were converted to cuboctahedral Au/Ag and Au nanocages and nanoframes with empty {111} faces through a galvanic replacement reaction. The nanocages showed a progressive plasmonic band red‐shift with increasing Au content. The nanocages exhibited high and stable photothermal efficiency with solution temperatures quickly reaching beyond 100 °C when irradiated with an 808 nm laser for large heat and water vapor generation.
Decarboxylative Trifluoromethylating Reagent [Cu(O2CCF3)(phen)] and Difluorocarbene Precursor [Cu(phen)2][O2CCF2Cl]
Authors: Lin Xiaoxi , Hou Chuanqi , Li Haohong , Weng Zhiqiang 
Published: January 2016

AbstractThis article describes the new economic decarboxylative trifluoromethylating reagent [Cu(phen)(O2CCF3)] (1; phen=1,10‐phenanthroline) and the efficient difluorocarbene precursor [Cu(phen)2][O2CCF2Cl] (2). Treatment of copper tert‐butoxide with phen and subsequent addition of trifluoroacetic acid or chlorodifluoroacetic acid afforded air‐stable complexes 1 and 2, respectively, which were characterized by X‐ray crystallography. The copper(I) ion in 1 is coordinated by a bidentate phen ligand, a monodentate trifluoroacetate group, and a molecule of CH3CN in a distorted tetrahedral coordination geometry. The molecular structure of 2 adopts an ionic form that consists of a [Cu(phen)2]+ cation and a chlorodifluoroacetate anion. Complex 1 reacted with a variety of aryl and heteroaryl halides to form trifluoromethyl (hetero)arenes in good yields. The corresponding Hammett plot exhibited a linear relationship and a reaction parameter (ρ)=+0.56±0.02, which indicated that the trifluoromethylation reaction proceeded via a nucleophilic reactive species. Complex 2 reacts with phenols to produce aryl difluoromethyl ethers in modest‐to‐excellent yields. Mechanistic investigations revealed that the difluoromethylation reaction proceeds by initial copper‐mediated formation of difluorocarbene and subsequent concerted addition of difluorocarbene to the phenol to form a three‐center transition state.
Generation of Oxazolidine‐2,4‐diones Bearing Sulfur‐Substituted Quaternary Carbon Atoms by Oxothiolation/Cyclization of Ynamides
Authors: Huang Hai , Fan Junzhen , He Guangke , Yang Zhimin , Jin Xiaodong , Liu Qi , Zhu Hongjun 
Published: January 2016

AbstractA novel method for metal‐free oxothiolation of ynamides to construct oxazolidine‐2,4‐diones bearing sulfur‐substituted quaternary carbon atoms has been developed. It represents a rare C−O bond cleavage of ynamides, as well as a facile and tandem approach for the formation of C−O, C−S, and C−Cl bonds. This redox‐neutral protocol can be applied to the synthesis of multisubstituted oxazolidine‐2,4‐diones with good chemoselectivity and good yields of isolated products under mild conditions.
Point‐to‐Plane Nonhomogeneous Electric‐Field‐Induced Simultaneous Formation of Giant Unilamellar Vesicles (GUVs) and Lipid Tubes
Authors: Zhu Chuntao , Zhang Ying , Wang Yinan , Li Qingchuan , Mu Wei , Han Xiaojun 
Published: January 2016

AbstractIt is well‐known that homogeneous electric fields can be used to generate giant unilamellar vesicles (GUVs). Herein we report an interesting phenomenon of formation of GUVs and lipid tubes simultaneously using a nonhomogeneous electric field generated by point‐to‐plane electrodes. The underlying mechanism was analyzed using finite element analysis. The two forces play main roles, that is, the pulling force (F) to drag GUVs into lipid tubes induced by fluid flow, and the critical force (Fc) to prevent GUVs from deforming into lipid tubes induced by electric fields. In the center area underneath the needle electrode, the GUVs were found because F is less than Fc in that region, whereas in the edge area the lipid tubes were obtained because F is larger than Fc. The diffusion coefficient of lipid in the tubes was found to be 4.45 μm2 s−1 using a fluorescence recovery after photobleaching (FRAP) technique. The method demonstrated here is superior to conventional GUV or lipid tube fabrication methods, and has great potential in cell mimic or hollow material fabrication using GUVs and tubes as templates.
Fully C/N‐Polynitro‐Functionalized 2,2′‐Biimidazole Derivatives as Nitrogen‐ and Oxygen‐Rich Energetic Salts
Authors: Yin Ping , He Chunlin , Shreeve Jean'ne M. 
Published: January 2016

AbstractThrough the use of a fully C/N‐functionalized imidazole‐based anion, it was possible to prepare nitrogen‐ and oxygen‐rich energetic salts. When N,N‐dinitramino imidazole was paired with nitrogen‐rich bases, versatile ionic derivatives were prepared and fully characterized by IR, and 1H, and 13C NMR spectroscopy and elemental analysis. Both experimental and theoretical evaluations show promising properties for these energetic compounds, such as high density, positive heats of formation, good oxygen balance, and acceptable stabilities. The energetic salts exhibit promising energetic performance comparable to the benchmark explosive RDX (1,3,5‐trinitrotriazacyclohexane).
Cytotoxicity of Postmodified Zeolitic Imidazolate Framework‐90 (ZIF‐90) Nanocrystals: Correlation between Functionality and Toxicity
Authors: Yen Chia‐I , Liu Szu‐Mam , Lo Wei‐Shang , Wu Jhe‐Wei , Liu Yi‐Hsin , Chein Rong‐Jie , Yang Renqiang , Wu Kevin C.‐W. , Hwu Jih Ru , Ma Nianhan , Shieh Fa‐Kuen 
Published: January 2016

AbstractUsing a simple method, the aldehyde groups of zeolitic imidazolate framework‐90 (ZIF‐90) nanocrystals were converted into carboxyl, amino, and thiol groups, without affecting the integrity of the framework. Notably, for the first time, correlations between functionality and cytotoxicity are also demonstrated via in vitro cytotoxicity assays. The positive charged aminated‐ZIF‐90 presumably results in either perturbation of cell membrane, more efficient cell uptake, or both. Therefore, the half‐maximal effective (EC50) concentration of aminated‐ZIF‐90 has a higher cytotoxicity of about 30 μg mL−1.
Partial oxidation of methane to syngas over Pt/Rh/MgO catalyst supported on FeCralloy woven fibre
Authors: Ma Zhenni , Ouzilleau Philippe , Trevisanut Cristian , Neagoe Cristian , Lotfi Samira , Boffito Daria C. , Patience Gregory S. 
Published: January 2016

AbstractIntegrating a high‐pressure syngas step with Fischer‐Tropsch synthesis (FT) in a single vessel reduces investment and operating costs for Gas‐to‐Liquids technology (GtL). Methane catalytic partial oxidation (CPOX) to produce syngas for FT is an economic opportunity for micro‐refineries. Many metals and metal oxides selectively convert natural gas to CO and , but they also form coke, which must be removed intermittently, otherwise it deactivates the catalyst and can foul the reactor and process lines. Here, we prepared a 1 % mass fraction (0.01 g/g) Pt/Rh (Pt/Rh = 9) catalyst supported on MgO over FeCralloy woven fibre via solution combustion synthesis. At 900 °C, from 0.1–2 MPa, and with a 2:1 feed composition of to , the reaction consumed all the oxygen and we obtained a ratio of 2 (ideal for FT). At low pressure and a 0.1 s residence time the catalyst converted 90 % of the methane at 90 % CO selectivity. At 2 MPa, CO yield reached 50 % ( 80 % conversion and 57 % selectivity). Based on thermodynamic calculations, less than 5 % coke forms below . At high pressure and short residence time (0.1 s), the coke yield (presumed to be coke crystallites) was 24 %. Increasing the residence time to 0.3 s reduced the amount of coke by 33 % because it is metastable.
New Insight into the Structure–Activity Relationships of the Selective Excitatory Amino Acid Transporter Subtype 1 (EAAT1) Inhibitors UCPH‐101 and UCPH‐102
Authors: Hansen Stinne W. , Erichsen Mette N. , Huynh Tri H. V. , Ruiz Josep A. , Haym Isabell , Bjørn‐Yoshimoto Walden E. , Abrahamsen Bjarke , Hansen Jeanette , Storgaard Morten , Eriksen Anette L. , Jensen Anders A. , Bunch Lennart 
Published: January 2016

AbstractIn the present study, we made further investigations on the structure–activity requirements of the selective excitatory amino acid transporter 1 (EAAT1) inhibitor, 2‐amino‐4‐(4‐methoxyphenyl)‐7‐(naphthalen‐1‐yl)‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromene‐3‐carbonitrile (UCPH‐101), by exploring 15 different substituents (R1) at the 7‐position in combination with eight different substituents (R2) at the 4‐position. Among the 63 new analogues synthesized, we identified a number of compounds that unexpectedly displayed inhibitory activities at EAAT1 in light of understanding the structure–activity relationship (SAR) of this inhibitor class extracted from previous studies. Moreover, the nature of the R1 and R2 substituents were observed to contribute to the functional properties of the various analogues in additive and non‐additive ways. Finally, separation of the four stereoisomers of analogue 14 g (2‐amino‐4‐([1,1′‐biphenyl]‐4‐yl)‐3‐cyano‐7‐isopropyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromene) was carried out, and in agreement with a study of a related scaffold, the R configuration at C4 was found to be mandatory for inhibitory activity, while both the C7 diastereomers were found to be active as EAAT1 inhibitors. A study of the stereochemical stability of the four pure stereoisomers 14 g‐A–D showed that epimerization takes places at C7 via a ring‐opening, C−C bond rotation, ring‐closing mechanism.
Relaxing the maximum dc input amplitude vs. consumption trade‐off in differential‐input band‐pass biquad filters
Authors: Oreggioni Julián , Castro‐Lisboa Pablo , Silveira Fernando 
Published: January 2016

SummaryThis paper shows that an important part of the power consumption of a biquad band‐pass filter is associated with the feedback loop that fixes the high‐pass frequency and blocks the direct current (dc) input signals. The dc input amplitude that can be blocked is related to the maximum output current that one of the transconductors can provide, hence impacting on the required consumption through this effect. Then, a technique that efficiently blocks the dc input signal and fixes the high‐pass frequency is introduced and analyzed in depth. Moreover, an architecture for ultra‐low‐power differential‐input biquads is fully presented. The proposed architecture enables lowering the power consumption or blocking higher levels of dc input without jeopardizing the power consumption. Results show that the proposed architecture, compared with a traditional one, presents a 30% reduction in power consumption and more than doubles the dc input that can be blocked. Copyright © 2016 John Wiley & Sons, Ltd.
Will climate change impact the potential distribution of a native vine (Merremia peltata) which is behaving invasively in the Pacific region?
Authors: Taylor Subhashni , Kumar Lalit 
Published: January 2016

AbstractMerremia peltata is a species with uncertain status in the island nations of the Pacific region. It has been designated introduced and invasive in some countries whereas it is considered native in others. Recent increase in its abundance across some island landscapes have led to calls for its designation as an invasive species of environmental concern with biological control being suggested as a control strategy. Climate change will add to the complications of managing this species since changes in climate will influence its range limits. In this study, we develop a process‐oriented niche model of M. peltata using CLIMEX to investigate the impacts of climate change on its potential distribution. Information on the climatic requirements of M. peltata and its current geographic distribution were used to calibrate the model. The results indicate that under current climate, 273,132 km2 of the land area in the region is climatically unsuitable or marginal for M. peltata whereas 664,524 km2 is suitable to highly suitable. Under current climate, areas of climatic suitability for M. peltata were identified on the archipelagos of Fiji, Papua New Guinea, Solomon Islands and Vanuatu. By the end of the century, some archipelagos like Fiji, Hawaii, New Caledonia and Vanuatu will probably become more suitable while PNG and Solomon Islands become less suitable for M. peltata. The results can be used to inform biosecurity planning, management and conservation strategies on islands.
Fixation probability of rare nonmutator and evolution of mutation rates
Authors: James Ananthu , Jain Kavita 
Published: January 2016

AbstractAlthough mutations drive the evolutionary process, the rates at which the mutations occur are themselves subject to evolutionary forces. Our purpose here is to understand the role of selection and random genetic drift in the evolution of mutation rates, and we address this question in asexual populations at mutation‐selection equilibrium neglecting selective sweeps. Using a multitype branching process, we calculate the fixation probability of a rare nonmutator in a large asexual population of mutators and find that a nonmutator is more likely to fix when the deleterious mutation rate of the mutator population is high. Compensatory mutations in the mutator population are found to decrease the fixation probability of a nonmutator when the selection coefficient is large. But, surprisingly, the fixation probability changes nonmonotonically with increasing compensatory mutation rate when the selection is mild. Using these results for the fixation probability and a drift‐barrier argument, we find a novel relationship between the mutation rates and the population size. We also discuss the time to fix the nonmutator in an adapted population of asexual mutators, and compare our results with experiments.
Effects of polyploidy and reproductive mode on life history trait expression
Authors: Larkin Katelyn , Tucci Claire , Neiman Maurine 
Published: January 2016

AbstractPloidy elevation is increasingly recognized as a common and important source of genomic variation. Even so, the consequences and biological significance of polyploidy remain unclear, especially in animals. Here, our goal was to identify potential life history costs and benefits of polyploidy by conducting a large multiyear common garden experiment in Potamopyrgus antipodarum, a New Zealand freshwater snail that is a model system for the study of ploidy variation, sexual reproduction, host–parasite coevolution, and invasion ecology. Sexual diploid and asexual triploid and tetraploid P. antipodarum frequently coexist, allowing for powerful direct comparisons across ploidy levels and reproductive modes. Asexual reproduction and polyploidy are very often associated in animals, allowing us to also use these comparisons to address the maintenance of sex, itself one of the most important unresolved questions in evolutionary biology. Our study revealed that sexual diploid P. antipodarum grow and mature substantially more slowly than their asexual polyploid counterparts. We detected a strong negative correlation between the rate of growth and age at reproductive maturity, suggesting that the relatively early maturation of asexual polyploid P. antipodarum is driven by relatively rapid growth. The absence of evidence for life history differences between triploid and tetraploid asexuals indicates that ploidy elevation is unlikely to underlie the differences in trait values that we detected between sexual and asexual snails. Finally, we found that sexual P. antipodarum did not experience discernable phenotypic variance‐related benefits of sex and were more likely to die before achieving reproductive maturity than the asexuals. Taken together, these results suggest that under benign conditions, polyploidy does not impose obvious life history costs in P. antipodarum and that sexual P. antipodarum persist despite substantial life history disadvantages relative to their asexual counterparts.