bluuebunny/crossref_metadata_2025 huggingface dataset:
Stick‐slip and creep behavior in lubricated granular material: Insights into the brittle‐ductile transition
Authors: Reber Jacqueline E. , Hayman Nicholas W. , Lavier Luc L.
Published: May 2014

Crustal deformation can occur via stick‐slip events, viscous creep, or strain transients at variable rates. Here we explore such strain transients with physical experiments comprising a quasi‐two‐dimensional shear zone with elastic, acrylic discs and interstitial viscous silicone. Experiments of solely elastic discs produce stick‐slip events and an overall (constant volume) strengthening. The addition of the viscous silicone enhances localization but does not greatly change the overall pattern of strengthening. It does, however, damp the stick‐slip events, leading to transient, creep‐like behavior that approaches the behavior of a Maxwell body. There is no gradual transition from frictional to viscous deformation with increasing amounts of silicone, suggesting that the mixed rheology is in effect as soon as an interstitial fluid is present. Our experiments support the hypothesis that a possible cause for strain transients in nature is an interstitial viscous phase in shear zones.
Exploring the cross correlations and autocorrelations of the ULF indices and incorporating the ULF indices into the systems science of the solar wind‐driven magnetosphere
Authors: Borovsky Joseph E. , Denton Michael H.
Published: May 2014

The ULF magnetospheric indicesSgr,Sgeo,Tgr, andTgeoare examined and correlated with solar wind variables, geomagnetic indices, and the multispacecraft‐averaged relativistic‐electron fluxFin the magnetosphere. The ULF indices are detrended by subtracting off sine waves with 24 h periods to formSgrd,Sgeod,Tgrd, andTgeod. The detrending improves correlations. Autocorrelation‐function analysis indicates that there are still strong 24 h period nonsinusoidal signals in the indices which should be removed in future. Indications are that the ground‐based indicesSgrdandTgrdare more predictable than the geosynchronous indicesSgeodandTgeod. In the analysis, a difference index ∆Smag ≈ Sgrd− 0.693Sgeodis derived: the time integral of ∆Smaghas the highest ULF index correlation with the relativistic‐electron fluxF. In systems‐science fashion, canonical correlation analysis (CCA) is used to correlate the relativistic‐electron flux simultaneously with the time integrals of (a) the solar wind velocity, (b) the solar wind number density, (c) the level of geomagnetic activity, (d) the ULF indices, and (e) the type of solar wind plasma (coronal hole versus streamer belt): The time integrals of the solar wind density and the type of plasma have the highest correlations withF. To create a solar wind‐Earth system of variables, the two indicesSgrdandSgeodare combined with seven geomagnetic indices; from this, CCA produces a canonical Earth variable that is matched with a canonical solar wind variable. Very high correlations (rcorr = 0.926) between the two canonical variables are obtained.
Altering the Substrate Specificity of Reductase CgKR1 from Candida glabrata by Protein Engineering for Bioreduction of Aromatic α‐Keto Esters
Authors: Huang Lei , Ma Hong‐Min , Yu Hui‐Lei , Xu Jian‐He
Published: May 2014

A versatile keto ester reductase CgKR1, exhibiting a broad substrate spectrum, was obtained from Candida glabrata by genome data mining. It showed the highest activity toward an aliphatic β‐keto ester, ethyl 4‐chloro‐3‐oxobutanoate (COBE), but much lower activity toward bulkier α‐keto esters with an aromatic group, such as methyl ortho‐chlorobenzoylformate (CBFM) and ethyl 2‐oxo‐4‐phenylbutyrate (OPBE). By rational design of the active pocket, the substrate specificity of the reductase was significantly altered and this tailor‐made reductase showed a much higher activity toward aromatic α‐keto esters (∼7‐fold increase in kcat/Km toward CBFM) and lower activity toward aliphatic keto esters (∼12‐fold decrease in kcat/Km toward COBE). Meanwhile, the thermostability of the reductase was enhanced by a consensus approach. Such improvements may yield practical catalysts for the asymmetric bioreduction of these aromatic α‐keto esters

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Scandium‐Catalyzed Cascade Cyclization to Produce Cyclobutane‐Fused Tetrahydroquinoline, Chromane, Thiochromane, and Tetrahydronaphthalene Derivatives
Authors: Nakano Shun‐ichi , Kakugawa Kazumi , Nemoto Tetsuhiro , Hamada Yasumasa
Published: May 2014

We have succeeded in the highly diastereoselective synthesis of cyclobutane‐fused multi‐cyclic compounds using a scandium‐catalyzed cascade cyclization. Using 3–10 mol% of scandium(III) triflate [Sc(OTf)3], various cyclobutane‐fused tetrahydroquinoline derivatives as well as its chromane, thiochromane, and tetrahydronaphthalene analogues were obtained in good to excellent yields. Derivatizations of the reaction products, as well as the plausible reaction mechanism, are also discussed.

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Poly(4‐vinylimidazolium)s/Diazabicyclo[5.4.0]undec‐7‐ene/Zinc(II) Bromide‐Catalyzed Cycloaddition of Carbon Dioxide to Epoxides
Authors: Seo Ue Ryung , Chung Young Keun
Published: May 2014

Poly(4‐vinylimidazolium)s, derived from the self‐immobilization of 4‐vinylimidazoliums, with diazabicyclo[5.4.0]undec‐7‐ene (DBU) and zinc bromide (ZnBr2) are used as a highly efficient catalyst for the chemical fixation of carbon dioxide. This catalytic system has been applied for the preparation of cyclic carbonates from terminal epoxides and carbon dioxide. Many functional groups, including chloro, vinyl, ether, and hydroxy groups are well tolerated in the reactions. Moreover, the catalytic system was found to catalyze the conversion of more sterically congested epoxides which are generally considered to be challenging substrates for fabricating the cyclic organic carbonates. In addition, the disubstituted epoxides are found to react with retention of configuration. The polymer precatalyst is easily recovered and reused. A plausible reaction mechanism is proposed.

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Improved and Practical Synthesis of [2,4,5‐Tris(trimethylsilyl)‐ phenyl](phenyl)iodonium Triflate and Utilization as a 1,4‐Benzdiyne Synthon
Authors: Gondo Keisuke , Kitamura Tsugio
Published: May 2014

An efficient and improved method for preparing [2,4,5‐tris(trimethylsilyl)phenyl](phenyl)iodonium triflate as a 1,4‐benzdiyne synthon was developed by using phenyiodonium diacetate/boron triflouride⋅diethyl etherate [PhI(OAc)2/BF3⋅OEt2] reagent. The iodonium triflate generated 3,4‐bis(trimethylsilyl)benzyne quantitatively to give cycloadducts with tetraphenylcyclopentadienone, furan and anthracene in high yields. These cycloadducts bearing two trimethylsilyl groups were transformed into the corresponding aryne precursors, which underwent subsequent cycloaddition reactions to afford polycyclic aromatic compounds such as 1,4‐dihydro‐1,4‐epoxyanthracene, naphthotriazole, triptycene, and anthratriazole derivatives in good to high yields. The total reactions are formally considered as double cycloaddition reactions of 1,4‐benzdiyne. This practical and useful formal benzdiyne strategy is described.

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Mesoporous TiO2‐Sn/C Core‐Shell Nanowire Arrays as High‐Performance 3D Anodes for Li‐Ion Batteries
Authors: Liao Jin‐Yun , Manthiram Arumugam
Published: May 2014

Three‐dimensional mesoporous TiO2‐Sn/C core‐shell nanowire arrays are prepared on Ti foil as anodes for lithium‐ion batteries. Sn formed by a reduction of SnO2 is encapsulated into TiO2 nanowires and the carbon layer is coated onto it. For additive‐free, self‐supported anodes in Li‐ion batteries, this unique core‐shell composite structure can effectively buffer the volume change, suppress cracking, and improve the conductivity of the electrode during the discharge‐charge process, thus resulting in superior rate capability and excellent long‐term cycling stability. Specifically, the TiO2‐Sn/C nanowire arrays display rechargeable discharge capacities of 769, 663, 365, 193, and 90 mA h g−1 at 0.1C, 0.5C, 2C 10C, and 30C, respectively (1C = 335 mA g−1). Furthermore, the TiO2‐Sn/C nanowire arrays exhibit a capacity retention rate of 84.8% with a discharge capacity of over 160 mA h g−1, even after 100 cycles at a high current rate of 10C.
Variable‐emittance infrared electrochromic skins combining unique conducting polymers, ionic liquid electrolytes, microporous polymer membranes, and semiconductor/polymer coatings, for spacecraft thermal control
Authors: Chandrasekhar Prasanna , Zay Brian J. , Lawrence David , Caldwell Edmonia , Sheth Rubik , Stephan Ryan , Cornwell John
Published: May 2014

Variable emittance (ε) is a property vital for the increasing needs in thermal control of future microspacecraft. This article describes fabrication, function, and performance of thin‐film, flexible, variable‐emittance (V‐E) electrochromic skins that use a conducting polymer/‐Au/‐microporous membrane (CP/Au/µP) base, and a new, unique ionic liquid electrolyte (IonEl). Poly(aniline‐co‐diphenyl amine) with a long‐chain polymeric dopant is used as the CP. A unique, patented device design yields no barrier between the active, electrochromic CP surface and the external environment, except for a thin, infrared‐transparent semiconductor/polymer film that lowers solar absorptance [α(s)] and protects from atomic‐O/far‐UV. Use of the IonEl requires special activation methods. Data presented show tailorable ε variations from 0.19 to 0.90, Δε values of >0.50 (which is the highest reported thus far for any functional V‐E material, to our knowledge), α(s) < 0.35, and nearly indefinite cyclability. Extended space durability testing, including calorimetric thermal vacuum and continuous light/dark cycling over >7 months under space conditions (<10−5Pa vacuum, far‐UV), show excellent durability. Other data show resistance to solar wind, atomic‐O, electrostatic discharge, and micrometeoroids. These lightweight, inexpensive, advanced polymeric materials represent the only technology that can work with micro‐ (<20 kg) and nano‐ (<2 kg) spacecraft, thus eventually allowing for much greater flexibility in their design and potentially “democratizing” the entire space industry, for example, allowing small firms to launch their own, dedicated satellites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 40850.
Polymer‐based route to ferroelectric lead strontium titanate thin films
Authors: Benkler Manuel , Hobmaier Jost , Gleißner Uwe , Medesi Anna , Hertkorn Daniel , Hanemann Thomas
Published: May 2014

Ceramic films with high values of ferroelectricity, piezoelectricity, and dielectricity with perovskite structure, like lead zirconate titanate (PZT, PbZrxTi1‐xO3), lead strontium titanate (PST, PbxSr1‐xTiO3), and barium strontium titanate (BST, BaxSr1−xTiO3), are subjects of intensive research due to their use in sensors, energy harvesters, capacitors, and FeRAMs. Here a novel, simple way to produce micropatterned perovskite PST thin films on silicon substrates by a polymer‐based direct UV‐lithography process is presented. By acrylic acid modification of PST precursor sols it is possible to generate photosensitive metal organic PST precursor xerogel films by spin‐coating and subsequently drying on silicon wafers. These films can be patterned by UV‐lithography and developed with organic solvents. The resulting patterned gel films can be crystallized in air via rapid thermal annealing. The obtained perovskite thin ceramic films are polycrystalline and fine grained. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40901.
Preparation of polymer electrolytes based on the polymerized imidazolium ionic liquid and their applications in lithium batteries
Authors: Li Mingtao , Wang Lu , Du Tingting
Published: May 2014

The polymer electrolytes based on a polymerized ionic liquid (PIL) as polymer host and containing 1,2‐dimethyl‐3‐butylimidazolium bis(trifluoromethanesulfonyl)imide (BMMIM‐TFSI) ionic liquid, lithium TFSI salt, and nanosilica are prepared. The PIL electrolyte presents a high ionic conductivity, and it is 1.07 × 10−3 S cm−1 at 60°C, when the BMMIM‐TFSI content reaches 60% (the weight ratio of BMMIM‐TFSI/PIL). Furthermore, the electrolyte exhibits wide electrochemical stability window and good lithium stripping/plating performance. Preliminary battery tests show that Li/LiFePO4 cells with the PIL electrolytes are capable to deliver above 146 mAh g−1 at 60°C with very good capacity retention. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40928.
Can the impact of non‐Western academic books be measured? An investigation of Google Books and Google Scholar for Malaysia
Authors: Abrizah A. , Thelwall Mike
Published: May 2014

Citation indicators are increasingly used in book‐based disciplines to support peer review in the evaluation of authors and to gauge the prestige of publishers. However, because global citation databases seem to offer weak coverage of books outside the West, it is not clear whether the influence of non‐Western books can be assessed with citations. To investigate this, citations were extracted from Google Books and Google Scholar to 1,357 arts, humanities and social sciences (AHSS) books published by 5 university presses during 1961–2012 in 1 non‐Western nation, Malaysia. A significant minority of the books (23% in Google Books and 37% in Google Scholar, 45% in total) had been cited, with a higher proportion cited if they were older or in English. The combination of Google Books and Google Scholar is therefore recommended, with some provisos, for non‐Western countries seeking to differentiate between books with some impact and books with no impact, to identify the highly‐cited works or to develop an indicator of academic publisher prestige.
Social impact of scholarly articles in a citation network
Authors: García Jose A. , Rodriguez‐Sánchez Rosa , Fdez‐Valdivia Joaquín
Published: May 2014

The intent of this article is to use cooperative game theory to predict the level of social impact of scholarly papers created by citation networks. Social impact of papers can be defined as the net effect of citations on a network. A publication exerts direct and indirect influence on others (e.g., by citing articles) and is itself influenced directly and indirectly (e.g., by cited articles). This network leads to an influence structure of citing and cited publications. Drawing on cooperative game theory, our research problem is to translate into mathematical equations the rules that govern the social impact of a paper in a citation network. In this article, we show that when citation relationships between academic papers function within a citation structure, the result is social impact instead of the (individual) citation impact of each paper. Mathematical equations explain the interaction between papers in such a citation structure. The equations show that the social impact of a paper is affected by the (individual) citation impact of citing publications, immediacy of citing articles, and number of both citing and cited papers. Examples are provided for several academic papers.
Variability of weather regimes in the North Atlantic‐European area: past and future
Authors: Hertig Elke , Jacobeit Jucundus
Published: May 2014

The concept of weather regimes represents a process‐oriented method of organizing the varying states of the atmospheric circulation. We define weather regimes as preferred, or recurrent, circulation patterns. We use a suite of reanalysis products and general circulation model (GCM) simulations to assess the reproducibility and variability of the regimes. We find distinct variability of the regimes in observational periods as well as in future projections. Most notable is the high variability of the North Atlantic Oscillation (NAO) regime anomaly patterns in the GCM simulations which is not evident in reanalyses, and the substantial increase of variability regarding the frequency of occurrence of the Atlantic ridge regime and the NAO+ regime.
Understanding and representing atmospheric convection across scales: recommendations from the meeting held at Dartington Hall, Devon, UK, 28–30 January 2013
Authors: Holloway Christopher E. , Petch Jon C. , Beare Robert J. , Bechtold Peter , Craig George C. , Derbyshire Stephen H. , Donner Leo J. , Field Paul R. , Gray Suzanne L. , Marsham John H. , Parker Douglas J. , Plant Robert S. , Roberts Nigel M. , Schultz David M. , Stirling Alison J. , Woolnough Steven J.
Published: May 2014

As weather and climate models move towards higher resolution, there is growing excitement about potential future improvements in the understanding and prediction of atmospheric convection and its interaction with larger‐scale phenomena. A meeting in January 2013 in Dartington, Devon was convened to address the best way to maximise these improvements, specifically in a UK context but with international relevance. Specific recommendations included increased convective‐scale observations, high‐resolution virtual laboratories, and a system of parameterization test beds with a range of complexities. The main recommendation was to facilitate the development of physically based convective parameterizations that are scale‐aware, non‐local, non‐equilibrium, and stochastic.
Development of all‐in‐one multicistronic Tet‐On lentiviral vectors for inducible co‐expression of two transgenes
Authors: Huang Yide , Zhen Ruonan , Jiang Meiqin , Yang Jie , Yang Yun , Huang Zhen , Lin Yao
Published: May 2014

Inducible co‐expression of multiple genes is often needed in research. Here we describe a single‐vector‐based Tet‐On inducible system for co‐expression of two transgenes. The two transgenes (DsRed1 and eGFP as model genes) and reverse tetracycline‐controlled transactivator were separated by internal ribosomal entry sites and 2A sequences, and their transcription was controlled by the same tetracycline responsive element. Two novel vectors with different internal ribosomal entry sites and 2A positions on the vectors were constructed. The DsRed1 and eGFP in cells transduced with both vectors are undetectable in the absence of doxycycline and can be efficiently induced in the presence of doxycycline in vitro and in vivo. These two vectors can be useful tools when regulated co‐expression of two ecotopic genes is needed.
Self‐reported immature defense style as a predictor of outcome in short‐term and long‐term psychotherapy
Authors: Laaksonen Maarit A. , Sirkiä Carlos , Knekt Paul , Lindfors Olavi
Published: May 2014

Objective

Identification of pretreatment patient characteristics predictive of psychotherapy outcome could help to guide treatment choices. This study evaluates patients' initial level of immature defense style as a predictor of the outcome of short‐term versus long‐term psychotherapy.

Method

In the Helsinki Psychotherapy Study, 326 adult outpatients with mood or anxiety disorder were randomized to individual short‐term (psychodynamic or solution‐focused) or long‐term (psychodynamic) psychotherapy. Their defense style was assessed at baseline using the 88‐item Defense Style Questionnaire and classified as low or high around the median value of the respective score. Both specific (Beck Depression Inventory [BDI], Hamilton Depression Rating Scale [HDRS], Symptom Check List Anxiety Scale [SCL‐90‐Anx], Hamilton Anxiety Rating Scale [HARS]) and global (Symptom Check List Global Severity Index [SCL‐90‐GSI], Global Assessment of Functioning Scale [GAF]) psychiatric symptoms were measured at baseline and 3–7 times during a 3‐year follow‐up.

Results

Patients with high use of immature defense style experienced greater symptom reduction in long‐term than in short‐term psychotherapy by the end of the 3‐year follow‐up (50% vs. 34%). Patients with low use of immature defense style experienced faster symptom reduction in short‐term than in long‐term psychotherapy during the first year of follow‐up (34% vs. 19%).

Conclusion

Knowledge of patients' initial level of immature defense style may potentially be utilized in tailoring treatments. Further research on defense styles as outcome predictors in psychotherapies of different types is needed.
Phosphoramidates as Novel Activity‐Based Probes for Serine Proteases
Authors: Haedke Ute R. , Frommel Sandra C. , Hansen Fabian , Hahne Hannes , Kuster Bernhard , Bogyo Matthew , Verhelst Steven H. L.
Published: May 2014

Activity‐based probes (ABPs) are small molecules that exclusively form covalent bonds with catalytically active enzymes. In the last decade, they have especially been used in functional proteomics studies of proteases. Here, we present phosphoramidate peptides as a novel type of ABP for serine proteases. These molecules can be made in a straightforward manner by standard Fmoc‐based solid‐phase peptide synthesis, allowing rapid diversification. The resulting ABPs covalently bind different serine proteases, depending on the amino acid recognition element adjacent to the reactive group. A reporter tag enables downstream gel‐based analysis or LC‐MS/MS‐mediated identification of the targeted proteases. Overall, we believe that these readily accessible probes will provide new avenues for the functional study of serine proteases in complex proteomes.
OPLS methods for the analysis of hyperspectral images—comparison with MCR‐ALS
Authors: Dumarey Melanie , Galindo‐Prieto Beatriz , Fransson Magnus , Josefson Mats , Trygg Johan
Published: May 2014

Two new, orthogonal projections to latent structures (OPLS) based methods were proposed to analyze hyperspectral images, enabling the visualization of multiple chemical compounds in one matrix without the need of extensive preprocessing. Both proposed methods delivered images representing the chemical distribution in the ribbon similar to the more traditional multivariate curve resolution–alternating least squares (MCR‐ALS) method, but their image background was less dynamic resulting in a stronger chemical contrast. This indicated that the methods successfully removed structured variation orthogonal to the chemical information (pure spectra of individual compounds), which was confirmed by the fact that physical scattering effects caused by grooves and edges were captured in the images visualizing the orthogonal components of the model. Hereby, the OPLS‐based method employing the pure spectra as weights in the OPLS algorithm was more successful in distinguishing compounds with a similar spectral signal than the transposed OPLS algorithm (pure spectra of individual compounds were used as response in OPLS model). It should be noted that for the main compounds, the MCR‐ALS method enabled easier visual interpretation compared to the OPLS‐based methods by setting all values below zero to zero, resulting in a higher contrast between pixels containing the studied compound and pixels not containing that compound. Copyright © 2014 John Wiley & Sons, Ltd.
Mechanistic Investigation of the Reaction of Epoxides with Heterocumulenes Catalysed by a Bimetallic Aluminium Salen Complex
Authors: Beattie Christopher , North Michael
Published: May 2014

The bimetallic aluminium(salen) complex [(Al(salen))2O] is known to catalyse the reaction between epoxides and heterocumulenes (carbon dioxide, carbon disulfide and isocyanates) leading to five‐membered ring heterocycles. Despite their apparent similarities, these three reactions have very different mechanistic features, and a kinetic study of oxazolidinone synthesis combined with previous kinetic work on cyclic carbonate and cyclic dithiocarbonate synthesis showed that all three reactions follow different rate equations. An NMR study of [Al(salen)]2O and phenylisocyanate provided evidence for an interaction between them, consistent with the rate equation data. A variable‐temperature kinetics study on all three reactions showed that cyclic carbonate synthesis had a lower enthalpy of activation and a more negative entropy of activation than the other two heterocycle syntheses. The kinetic study was extended to oxazolidinone synthesis catalysed by the monometallic complex Al(salen)Cl, and this reaction was found to have a much less negative entropy of activation than any reaction catalysed by [Al(salen)]2O, a result that can be explained by the partial dissociation of an oligomeric Al(salen)Cl complex. A mechanistic rationale for all of the results is presented in terms of [Al(salen)]2O being able to function as a Lewis acid and/or a Lewis base, depending upon the susceptibility of the heterocumulene to reaction with nucleophiles.
Long‐Range Chemical Ligation from N→N Acyl Migrations in Tryptophan Peptides via Cyclic Transition States of 10‐ to 18‐Members
Authors: Biswas Suvendu , Kayaleh Roger , Pillai Girinath G. , Seon Christopher , Roberts Ian , Popov Vadim , Alamry Khalid A. , Katritzky Alan R.
Published: May 2014

Chemical ligations to form native peptides from N→N acyl migrations in Trp‐containing peptides via 10‐ to 18‐membered cyclic transition states are described. In this study, a statistical, predictive model that uses an extensive synthetic and computational approach to rationalize the chemical ligation is reported. N→N acyl migrations that form longer native peptides without the use of Cys/Ser/Tyr residues or an auxiliary group at the ligation site were achieved. The feasibility of these traceless chemical ligations is supported by the NC bond distance in N‐acyl isopeptides. The intramolecular nature of the chemical ligations is justified by using competitive experiments and theoretical calculations.
Vibrational Spectra of Chemical and Isotopic Variants of Oxyluciferin, the Light Emitter of Firefly Bioluminescence
Authors: Maltsev Oleg V. , Yue Ling , Rebarz Mateusz , Hintermann Lukas , Sliwa Michel , Ruckebusch Cyril , Pejov Ljupčo , Liu Ya‐Jun , Naumov Panče
Published: May 2014

The chemical complexity of oxyluciferin (OxyLH2), the light‐emitting molecule in the bioluminescence of fireflies, originates from the possibility of keto/enol tautomerism and single or double deprotonation. Herein, we present detailed infrared spectroscopic analysis of OxyLH2 and several of its chemical isomers and isotopomers. To facilitate the future characterization of its biogenic forms, we provide accurate assignments of the solid‐state and solution FTIR spectra of OxyLH2 based on comparison to six isotopically labeled variants ([2‐13C]‐OxyLH2, [3‐15N]‐OxyLH2, [4‐13C]‐OxyLH2, [5‐13C]‐OxyLH2, [2′‐13C]‐OxyLH2, [3′‐15N]‐OxyLH2), five closely related structural analogues, and theoretically computed spectra. The computed DFT harmonic vibrational force fields (B3LYP and M06 functionals with basis sets of varying flexibility up to 6‐311++G**) reproduce well the observed shifts in the IR spectra of both isotopically labeled and structurally related analogues.
Understanding Bacterial Bioluminescence: A Theoretical Study of the Entire Process, from Reduced Flavin to Light Emission
Authors: Hou Cong , Liu Ya‐Jun , Ferré Nicolas , Fang Wei‐Hai
Published: May 2014

Bacterial bioluminescence (BL) has been successfully applied in water‐quality monitoring and in vivo imaging. The attention of researchers has been attracted for several decades, but the mechanism of bacterial BL is still largely unknown due to the complexity of the multistep reaction process. Debates mainly focus on three key questions: How is the bioluminophore produced? What is the exact chemical form of the bioluminophore? How does the protein environment affect the light emission? Using quantum mechanics (QM), combined QM and molecular mechanics (QM/MM) and molecular dynamic (MD) calculations in gas‐phase, solvent and protein environments, the entire process of bacterial BL was investigated, from flavin reduction to light emission. This investigation revealed that: 1) the chemiluminescent decomposition of flavin peroxyhemiacetal does not occur through the intramolecular chemical initiated electron exchange luminescence (CIEEL) or the “dioxirane” mechanism, as suggested in the literature. Instead, the decomposition occurs according to the charge‐transfer initiated luminescence (CTIL) mechanism for the thermolysis of dioxetanone. 2) The first excited state of 4a‐hydroxy‐4a,5‐dihydroFMN (HFOH) was affirmed to be the bioluminophore of bacterial BL. This study provides details regarding the mechanism by which bacterial BL is produced and is helpful in understanding bacterial BL in general.
Mechanistic Study of a Switch in the Regioselectivity of Hydroheteroarylation of Styrene Catalyzed by Bimetallic Ni–Al through CH Activation
Authors: Chen Wen‐Ching , Lai Ying‐Chieh , Shih Wei‐Chun , Yu Ming‐Shiuan , Yap Glenn P. A. , Ong Tiow‐Gan
Published: May 2014

We previously reported a highly efficient protocol for bimetallic Ni–Al‐catalyzed hydroheteroarylation of styrene with benzimidazole based on CH bond activation. We have now delineated the mechanism of this process, providing a rationale for an observed switch in regioselectivity in the presence of the Lewis acid, AlMe3. The present mechanistic study gives insights for the rational development of catalysts that exhibit required linear/branched selectivity.
Preparation and Enantioselectivity Binding Studies of a New Chiral Cobalt(II)porphyrin‐Tröger's Base Conjugate
Authors: Tatar Ameneh , Valík Martin , Novotná Jana , Havlík Martin , Dolenský Bohumil , Král Vladimír , Urbanová Marie
Published: May 2014

A new bis[cobalt(II)porphyrin]‐Tröger's base conjugate was studied as a potential receptor for methyl esters of several amino acids. The conjugate was prepared as racemate, and then resolved via preparative high‐performance liquid chromatography (HPLC) on a chiral column. The high affinity to lysine, histidine, and proline methyl esters was found by complexation studies followed by UV‐Vis spectroscopy. The studies of pure enantiomers, followed by UV‐Vis and electronic circular dichroism spectroscopy, revealed the highest enantioselectivity for lysine methyl ester. Chirality 26:361–367, 2014. © 2014 Wiley Periodicals, Inc.
Comparative effectiveness of aggressive versus nonaggressive treatment among men with early‐stage prostate cancer and differing comorbid disease burdens at diagnosis
Authors: Daskivich Timothy J. , Lai Julie , Dick Andrew W. , Setodji Claude M. , Hanley Janet M. , Litwin Mark S. , Saigal Christopher ,   the Urologic Diseases in America Project
Published: May 2014

BACKGROUND

This study sought to compare the effectiveness of aggressive versus nonaggressive treatment in reducing cancer‐specific mortality for older men with early‐stage prostate cancer across differing comorbid disease burdens at diagnosis.

METHODS

In total, the authors sampled 140,553 men aged ≥66 years with early‐stage prostate cancer who were diagnosed between 1991 and 2007 from the Surveillance, Epidemiology, and End Results‐Medicare database. Propensity‐adjusted competing‐risks regression analysis was used to compare the risk of cancer‐specific mortality between men who received aggressive versus nonaggressive treatment among comorbidity subgroups.

RESULTS

In propensity‐adjusted competing‐risks regression analysis, aggressive treatment was associated with a significantly lower risk of cancer‐specific mortality among men who had Charlson scores of 0, 1, and 2 but not among men who had Charlson scores ≥3 (subhazard ratio, 0.85; 95% confidence interval, 0.62‐1.18). The absolute reduction in 15‐year cancer‐specific mortality between men who received aggressive versus nonaggressive treatment was 6.1%, 4.3%, 3.9%, and 0.9% for men with Charlson scores of 0, 1, 2, and ≥3, respectively. Among men who had well‐differentiated and moderately‐differentiated tumors, aggressive treatment again was associated with a lower risk of cancer‐specific mortality for those who had Charlson scores of 0, 1, and 2 but not for those who had Charlson scores ≥3 (subhazard ratio, 1.14; 95% confidence interval, 0.70‐1.89). The absolute reduction in 15‐year cancer‐specific mortality between men who received aggressive versus nonaggressive treatment was 3.8%, 3%, 1.9%, and −0.5% for men with Charlson scores of 0, 1, 2, and ≥3, respectively.

CONCLUSIONS

The cancer‐specific survival benefit from aggressive treatment for early‐stage prostate cancer diminishes with increasing comorbidity at diagnosis. Men with Charlson scores ≥3 garner no survival benefit from aggressive treatment. Cancer 2014;120:2432–2439. © 2014 American Cancer Society.
Climbing fiber projections in relation to zebrin stripes in the ventral uvula in pigeons
Authors: Pakan Janelle M.P. , Graham David J. , Wylie Douglas R.
Published: May 2014

The cerebellum consists of sagittally oriented zones that are delineated by afferent input, Purkinje cell response properties, and the expression of molecular markers such as zebrin II (ZII). ZII is heterogeneously expressed in Purkinje cells such that there are parasagittal stripes of high expression (ZII+) interdigitated with stripes of little or no expression (ZII−). In pigeons, folium IXcd consists of seven pairs of ZII+/− stripes denoted P1+/− (medial) to P7+/− (lateral). In the present study we examined the climbing fiber input to the medial half of folium IXcd, the ventral uvula, which spans the medial two stripe pairs (P1+/− to P2+/−). Purkinje cells in the ventral uvula respond to patterns of optic flow resulting from self‐motion through the environment along translational axes and their climbing fibers originate in the lateral half of the medial column in the inferior olive (mcIO). Using anterograde injections into this region of the mcIO, we found the following topographic relationship: climbing fibers from the caudal lateral mcIO were located in P1+ and medial P1− ZII stripes; climbing fibers from the rostral lateral mcIO were located in lateral P2+ and P2− ZII stripes, and climbing fibers from the middle lateral mcIO were located in lateral P1− and medial P2+ ZII stripes. These data complement our previous findings showing a topographic relationship between Purkinje cell responses to optic flow visual stimuli and ZII stripes. Taken together, we suggest that a ZII+/− stripe pair may represent a functional unit in the pigeon vestibulocerebellum. J. Comp. Neurol. 522:3629–3643, 2014. © 2014 Wiley Periodicals, Inc.
Intravenous pharmacokinetics, local tolerability, and hemolysis of an SBE7‐β‐cyclodextrin formulation of the neurokinin‐1 receptor antagonist vestipitant
Authors: Brigandi Richard A. , Russ Steven F. , Petit Chantal , Johnson Brendan , Croy Scott , Hodsman Peter , Muller Fran
Published: May 2014

Vestipitant is a potent and selective neurokinin 1 (NK‐1) receptor antagonist that was investigated as a potential treatment for post‐operative nausea and vomiting (PONV). A previous mannitol‐based formulation of vestipitant was associated with hemolytic activity in preclinical studies. In an effort to reduce the hemolytic potential and develop an IV formulation of vestipitant that could be administered more rapidly, an IV formulation containing sulfobutylether‐7‐beta‐cyclodextrin (SBE7‐β‐CD, Captisol™) was developed and tested in a phase 1 clinical study. This was a randomized, single‐blind (subjects and investigator—blinded, sponsor‐unblinded), placebo controlled, dose escalation study in healthy subjects in which 7 cohorts of 8 subjects per cohort received SBE7‐β‐CD ‐based vestipitant (2 mg/mL) or placebo (saline) in a 3:1 ratio (active:placebo) at different doses and infusion rates. The results demonstrated the ability to infuse up to 48 mg vestipitant in a 2 mg/mL formulation over 30 seconds with no evidence of hemolytic effects. Cohorts of subjects at lower doses and longer infusion duration (>1 minute) reported more AEs related to the infusion site than those at the higher doses and faster infusion rates.
Synthesis of Sulfonic Acid Containing Ionic‐Liquid‐Based Periodic Mesoporous Organosilica and Study of Its Catalytic Performance in the Esterification of Carboxylic Acids
Authors: Elhamifar Dawood , Karimi Babak , Moradi Abbas , Rastegar Javad
Published: May 2014

A new sulfonic acid containing ionic‐liquid‐based periodic mesoporous organosilica (PMO‐IL‐SO3H) material was prepared and its catalytic application was investigated in the esterification of carboxylic acids with alcohols. The PMO‐IL‐SO3H nanocatalyst was first characterized with diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and nitrogen sorption analysis. Then, the catalytic performance of this material was studied in the esterification of carboxylic acids with short‐ and long‐chain aliphatic alcohols, cyclic alcohols, and benzylic alcohols under solvent‐free conditions. The results showed that the catalyst has superior activity for the conversion of several alcohols to afford the corresponding ester products in excellent yields and high purity. Moreover, the catalyst could be recovered and reused several times without a significant decrease in activity and product selectivity.
Recycling Nanoparticle Catalysts without Separation Based on a Pickering Emulsion/Organic Biphasic System
Authors: Liu Huifang , Zhang Zhiming , Yang Hengquan , Cheng Fangqin , Du Zhiping
Published: May 2014

A conceptually novel methodology is explored for in situ recycling of nanoparticle catalysts based on transforming a conventional organic/aqueous biphasic system into a Pickering emulsion/organic biphasic system (PEOBS). The suggested PEOBS exists as two phases, with the nanoparticle catalyst “anchored” in the Pickering emulsion phase, but is “continuous” between the organic phase and the continuous phase of the Pickering emulsion. Aqueous hydrogenations are used to evaluate the reaction performances of PEOBS, and the underlying principles of PEOBS are preliminarily elaborated. The unique properties of PEOBS lead to many intriguing findings, which are unlikely to be achieved in the reported biphasic systems. PEOBS exhibits more than a fourfold enhancement in catalysis efficiency in comparison with a conventional biphasic system. Impressively, PEOBS enables the organic product to be facilely isolated through simple decantation and the nanoparticle catalyst can be recycled in situ without the need for “separation”. Its recycling effectiveness is justified by ten reaction cycles without significant catalyst loss. The simple protocol, in conjunction with the stability to simultaneously achieve high catalysis efficiency and excellent catalyst recyclability, makes PEOBS a promising methodology to develop more sustainable nanocatalysis.
A multi‐objective optimization model based on immune algorithm in wireless mesh networks
Authors: Chen Jing , He Kun , Du Ruiying , Yu Fajiang , Yuan Quan , Wang Lina , Fu Cai
Published: May 2014

With the characteristics of high self‐organized, dynamic, and interoperable, the wireless mesh network (WMN) is deemed as a potential technology to be applied widely for home, enterprise, and social public service. Many current optimization schemes usually focus on a single metric such as network deployment cost, throughput, QoS, and so on, but few schemes consider that the optimized metric may affect other metrics of WMN. In practice, the influence among the different metrics is often nonignorable. To optimize the performance from a global perspective, we propose a multi‐objective optimization model based on immune algorithm (MOM‐IA), which provides a paradigm to find the optimal solution satisfying some different restriction conditions. To simplify, MOM‐IA mainly analyzes the restriction relationship of connectivity, redundancy, and throughput, which are the multiple objects. Considering the characteristic of dynamic and the discrete integer parameters in WMN, we design a longtime evolution immune algorithm to solve the MOM. Finally, the analysis of experiments presents that MOM‐IA has good performance in solution set diversity and Pareto‐front distribution, which means the probability to find the optimal solution in WMN. Copyright © 2014 John Wiley & Sons, Ltd.
Desmoplastic small round cell tumor with sphere‐like clusters mimicking adenocarcinoma
Authors: Hattori Yukinori , Yoshida Akihiko , Sasaki Naoshi , Shibuki Yasuo , Tamura Kenji , Tsuta Koji
Published: May 2014

Desmoplastic small round cell tumor (DSRCT) is a rare and aggressive neoplasm that predominantly affects young men. DSRCT often presents as multiple nodules on the serosal surface and is histologically categorized as a small round cell tumor. However, the cytological spectrum of DSRCT is not fully understood because of its rarity. Here, we report an unusual case of DSRCT that showed spheres of cells without stromal cores in pleural fluid cytology material, a finding that is typically associated with metastatic adenocarcinoma and mesothelioma. The specimen from a simultaneous needle biopsy showed the classic histology of DSRCT, comprising nests of small round cells set in desmoplasia. The diagnosis of DSRCT was further supported by immunohistochemical coexpression of cytokeratin and desmin, as well as Ewing sarcoma breakpoint region 1 gene rearrangement, which was determined by fluorescence in situ hybridization. The unusual cytological finding in this case illustrates a potential pitfall of the cytological diagnosis of pleural fluid or ascites. DSRCT should not be excluded from the differential diagnosis when sphere‐like round cell clusters are observed in pleural or abdominal effusion, particularly in young male patients. Diagn. Cytopathol. 2015;43:214–217. © 2014 Wiley Periodicals, Inc.
Transcriptionally regulated cell adhesion network dictates distal tip cell directionality
Authors: Wong Ming‐Ching , Kennedy William P. , Schwarzbauer Jean E.
Published: May 2014

Background: The mechanisms that govern directional changes in cell migration are poorly understood. The migratory paths of two distal tip cells (DTC) determine the U‐shape of the C. elegans hermaphroditic gonad. The morphogenesis of this organ provides a model system to identify genes necessary for the DTCs to execute two stereotyped turns. Results: Using candidate genes for RNAi knockdown in a DTC‐specific strain, we identified two transcriptional regulators required for DTC turning: cbp‐1, the CBP/p300 transcriptional coactivator homologue, and let‐607, a CREBH transcription factor homologue. Further screening of potential target genes uncovered a network of integrin adhesion‐related genes that have roles in turning and are dependent on cbp‐1 and let‐607 for expression. These genes include src‐1/Src kinase, tln‐1/talin, pat‐2/α integrin and nmy‐2, a nonmuscle myosin heavy chain. Conclusions: Transcriptional regulation by means of cbp‐1 and let‐607 is crucial for determining directional changes during DTC migration. These regulators coordinate a gene network that is necessary for integrin‐mediated adhesion. Overall, these results suggest that directional changes in cell migration rely on the precise gene regulation of adhesion. Developmental Dynamics 243:999–1010, 2014. © 2014 Wiley Periodicals, Inc.
Endoderm‐specific deletion of Tbx1 reveals an FGF‐independent role for Tbx1 in pharyngeal apparatus morphogenesis
Authors: Jackson Abigail , Kasah Sahrunizam , Mansour Suzanne L. , Morrow Bernice , Basson M. Albert
Published: May 2014

Background: The T‐box transcription factor Tbx1, is essential for the normal development of multiple organ systems in the embryo. One of the most striking phenotypes in Tbx1−/− embryos is the failure of the caudal pharyngeal pouches to evaginate from the foregut endoderm. Despite considerable interest in the role of Tbx1 in development, the mechanisms whereby Tbx1 controls caudal pouch formation have remained elusive. In particular, the question as to how Tbx1 expression in the pharyngeal endoderm regulates pharyngeal pouch morphogenesis in the mouse embryo is not known. Results: To address this question, we produced mouse embryos in which Tbx1 was specifically deleted from the pharyngeal endoderm and, as expected, embryos failed to form caudal pharyngeal pouches. To determine the molecular mechanism, we examined expression of Fgf3 and Fgf8 ligands and downstream effectors. Although Fgf8 expression is greatly reduced in Tbx1‐deficient endoderm, FGF signaling levels are unaffected. Furthermore, pouch morphogenesis is only partially perturbed by the loss of both Fgf3 and Fgf8 from the endoderm, indicating that neither are required for pouch formation. Conclusions: Tbx1 deletion from the pharyngeal endoderm is sufficient to cause caudal pharyngeal arch segmentation defects by FGF‐independent effectors that remain to be identified. Developmental Dynamics 243:1143–1151, 2014. © 2014 Wiley Periodicals, Inc.
Development of Sensor and Control Systems of a Wearable Robot to Walk on a Step
Authors: Oda Yuki , Kagawa Takahiro , Uno Yoji
Published: May 2014

The goal of our study is to develop a system for walking on a step using a wearable robot. Our system consists of (1) sensing of a step from the movement of the walker, (2) detection of the foot placement state related to the step, and (3) generation of gait patterns of climbing and stepping down for the step. In the generation of gait patterns for the step, toe trajectories are generated according to the height of the step to avoid collision of the swinging leg with the step. The hip trajectory is generated by an optimization technique that minimizes the sum of the joint angular jerk of the robot subject to constraints on the hip position and the velocity at toe liftoff. Each joint angle trajectory is calculated from the generated trajectories by means of inverse kinematic equations. We investigated the feasibility of the proposed sensor and control systems for two steps with different heights.
Optimal Digital Controller Design for a Servo Motor Taking Account of Intersample Behavior
Authors: Akiyoshi Tatsuro , Imai Jun , Funabiki Shigeyuki
Published: May 2014

A continuous‐time plant with a discretized continuous‐time controller does not yield stability if the sampling rate is lower than some certain level. Thus far, high‐performance electronic control has made use of expensive hardware needed to implement discretized continuous‐time controllers; low‐cost hardware generally does not have a sufficiently high sampling rate. This technical note presents results comparing performance indexes with and without intersample behavior, and provides some answers to the question of how a low‐specification device can control a plant effectively. We consider a machine simulating wafer handling robots, which is an electromechanical system driven by a direct drive motor, at a semiconductor factory. We illustrate the controller design for the robot with and without intersample behavior, and present simulations and experimental results using these controllers. Taking intersample behavior into account proves to be effective in improving control performance and makes it possible to choose a relatively long sampling period. Controller design in terms of the performance index with intersample behavior makes it possible to deal with situations in which a sufficiently short sampling period may not be employed, and freedom of controller design may be widened, especially regarding the choice of the sampling period.