bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antimicrobial Poly(2‐methyloxazoline)s with Bioswitchable Activity through Satellite Group Modification
Authors: Krumm Christian , Harmuth Simon , Hijazi Montasser , Neugebauer Britta , Kampmann Anne‐Larissa , Geltenpoth Helma , Sickmann Albert , Tiller Joerg C. 
Published: March 2014

AbstractBiocides are widely used for preventing the spread of microbial infections and fouling of materials. Since their use can build up microbial resistance and cause unpredictable long‐term environmental problems, new biocidal agents are required. In this study, we demonstrate a concept in which an antimicrobial polymer is deactivated by the cleavage of a single group. Following the satellite group approach, a biocidal quaternary ammonium group was linked through a poly(2‐methyloxazoline) to an ester satellite group. The polymer with an octyl‐3‐propionoate satellite group shows very good antimicrobial activity against Gram‐positive bacterial strains. The biocidal polymer was also found to have low hemotoxicity, resulting in a high HC50/MIC value of 120 for S. aureus. Cleaving the ester satellite group resulted in a 30‐fold decrease in antimicrobial activity, proving the concept valid. The satellite group could also be cleaved by lipase showing that the antimicrobial activity of the new biocidal polymers is indeed bioswitchable.
Affinity precipitation of a monoclonal antibody from an industrial harvest feedstock using an ELP‐Z stimuli responsive biopolymer
Authors: Sheth Rahul D. , Jin Mi , Bhut Bharat V. , Li Zhengjian , Chen Wilfred , Cramer Steven M. 
Published: March 2014

ABSTRACTIn this work, a proof of concept elastin‐like polypeptide‐Z domain fusion (ELP‐Z) based affinity precipitation process is developed for monoclonal antibody (mAb) purification from industrial harvest feeds. Greater than 99% mAb recoveries are obtained during the initial binding step of the process for both pure mAb and the mAb harvest feeds. Great than 90% overall mAb yields are also obtained for the subsequent elution step of the process with no measurable mAb aggregation. The process is shown to result in more than 2 logs of host cell protein (HCP) and more than 4 logs of DNA clearance from the harvest feed. While the overall mAb yield and HCP clearance for the affinity precipitation process was comparable to Protein A chromatography the DNA clearance was clearly superior. Performance is maintained for mAb final elution concentrations up to 20 g/L, demonstrating the ability of the process to both concentrate and purify the mAb. Effective ELP‐Z regeneration is also demonstrated using 0.1 M NaOH with no adverse effect on subsequent capture efficiency. Finally, the reusability of the ELP‐Z construct and robustness of the process is demonstrated for up to three purification‐regeneration cycles with minimal product and impurity carryover and high yields and purity. This work demonstrates that the ELP‐Z based precipitation approach can be successfully employed as an affinity capture step for industrial mAbs. Biotechnol. Bioeng. 2014;111: 1595–1603. © 2014 Wiley Periodicals, Inc.
Activin A supplement in the hESCs culture enhances the endoderm differentiation efficiency
Authors: Guo Shuren , Mao Xiaohuan , He Fucheng , Liu Hongchun , Ming Liang 
Published: March 2014

AbstractActivin A is a critical regulator in human embryonic stem cells (hESCs) maintenance and differentiation. Different concentrations of Activin A affect hESC maintenance and differentiation in different ways. A high concentration favors anterior primitive streak and gives rise to DE if the stimulation persists. hESCs were cultured with and without 10 ng/mL Activin A supplement respectively. The two groups of cells were differentiated into endoderm cells with 100 ng/mL Activin A and other reagents. Microarray‐based DNA methylation was analyzed with the Infinium Human Methylation450 BeadChip on these two groups. There was a significant difference in endoderm differentiation efficiency (average efficiency: 71 vs. 58.5%, P < 0.05). hESCs cultured with Activin A supplement had an increased propensity to form definitive endoderm cells in response to Activin A and Wnt signal. Differentially Methylated Regions (DMRs) between these two groups were found. DMRs were related to the stem cell maintenance and gene regulation by peroxisome proliferators via PPARα, indicating that hESCs maintained with Activin A supplement had stronger “stemness.”
Michael Addition of N‐Unprotected 2‐Oxindoles to Nitrostyrene Catalyzed by Bifunctional Tertiary Amines: Crucial Role of Dispersion Interactions
Authors: Reiter Christoph , López‐Molina Sònia , Schmid Bernhard , Neiss Christian , Görling Andreas , Tsogoeva Svetlana B. 
Published: March 2014

AbstractBifunctional thiourea‐ or sulfonamide‐derived tertiary amines catalyze the enantioselective nitro‐Michael addition of N‐unprotected 3‐substituted 2‐oxindoles to nitrostyrene in up to 99 % yields, 94:6 er, and 87:13 dr. Overcoming the necessity to introduce and remove activating or protecting groups at the nitrogen moiety leads to a reduction of energy use, costs, and waste. Transition‐state geometries for the formation of all possible stereoisomers in the nitro‐Michael addition of N‐unprotected 3‐substituted 2‐oxindole to nitrostyrene catalyzed by Takemoto’s tertiary amine–thiourea are calculated. It is shown that the relative positions and binding patterns of the reactants and the catalyst molecule are largely determined by van der Waals interactions.
Ethylene Polymerization Catalyzed by Pyrene‐Tagged Iron Complexes: The Positive Effect of π‐Conjugation and Immobilization on Multiwalled Carbon Nanotubes
Authors: Zhang Liping , Zhang Wenjuan , Serp Philippe , Sun Wen‐Hua , Durand Jérôme 
Published: March 2014

Abstract2‐[1‐(2,6‐Diisopropylphenylimino)ethyl]‐6‐[1‐(pyren‐1‐ylimino)ethyl]pyridine (L1) and 2,6‐bis[1‐(pyren‐1‐ylimino)ethyl]pyridine (L2) were synthesized and used to prepare the corresponding Fe complexes Fe1 and Fe2 from FeCl2. All new compounds were characterized, and single‐crystal XRD analysis of Fe1 was performed. The π‐conjugated pyrenyl substituent enhanced the catalytic activity of the Fe complexes, which display high activity in ethylene polymerization up to 107 gPE molFe−1 h−1 (PE=polyethylene). These Fe complexes were easily immobilized on multiwalled carbon nanotubes (MWCNTs) through noncovalent π–π interactions. The supported precatalysts showed better ethylene polymerization activity than their homogeneous counterparts to produce well‐dispersed MWCNT/PE composite materials.
Aluminum‐Doped Hafnium Oxynitride: Effect of Cation Doping on Oxygen‐Reduction‐Reaction Activity in Acid Media
Authors: Chisaka Mitsuharu , Muramoto Hirokazu 
Published: March 2014

AbstractAl atoms are doped into Hf sites in HfOx nanoparticles supported on carbon black to incorporate O defects without decreasing the Hf valence. The oxygen reduction reaction activity is enhanced by the Al doping, and Al atoms are stable following the N doping into the O sites and accelerated degradation tests involving 20 000 potential cycles.
On the Importance of Decarbonylation as a Side‐Reaction in the Ruthenium‐Catalysed Dehydrogenation of Alcohols: A Combined Experimental and Density Functional Study
Authors: Sieffert Nicolas , Réocreux Romain , Lorusso Patrizia , Cole‐Hamilton David J. , Bühl Michael 
Published: March 2014

AbstractWe report a density functional study (B97‐D2 level) of the mechanism(s) operating in the alcohol decarbonylation that occurs as an important side‐reaction during dehydrogenation catalysed by [RuH2(H2)(PPh3)3]. By using MeOH as the substrate, three distinct pathways have been fully characterised involving either neutral tris‐ or bis‐phosphines or anionic bis‐phosphine complexes after deprotonation. α‐Agostic formaldehyde and formyl complexes are key intermediates, and the computed rate‐limiting barriers are similar between the various decarbonylation and dehydrogenation paths. The key steps have also been studied for reactions involving EtOH and iPrOH as substrates, rationalising the known resistance of the latter towards decarbonylation. Kinetic isotope effects (KIEs) were predicted computationally for all pathways and studied experimentally for one specific decarbonylation path designed to start from [RuH(OCH3)(PPh3)3]. From the good agreement between computed and experimental KIEs (observed kH/kD=4), the rate‐limiting step for methanol decarbonylation has been ascribed to the formation of the first agostic intermediate from a transient formaldehyde complex.
[RhIII(Cp*)]‐Catalyzed ortho‐Selective Direct C(sp2)H Bond Amidation/Amination of Benzoic Acids by N‐Chlorocarbamates and N‐Chloromorpholines. A Versatile Synthesis of Functionalized Anthranilic Acids
Authors: Ng Fo‐Ning , Zhou Zhongyuan , Yu Wing‐Yiu 
Published: March 2014

AbstractA RhIII‐catalyzed direct ortho‐CH amidation/amination of benzoic acids with N‐chlorocarbamates/N‐chloromorpholines was achieved, giving anthranilic acids in up to 85 % yields with excellent ortho‐selectivity and functional‐group tolerance. Successful benzoic acid aminations were achieved with carbamates bearing various amide groups including NHCO2Me, NHCbz, and NHTroc (Cbz=carbobenzyloxy; Troc=trichloroethylchloroformate), as well as secondary amines, such as morpholines, piperizines, and piperidines, furnishing highly functionalized anthranilic acids. A stoichiometric reaction of a cyclometallated rhodium(III) complex of benzo[h]quinoline with a silver salt of N‐chlorocarbamate afforded an amido–rhodium(III) complex, which was isolated and structurally characterized by X‐ray crystallography. This finding confirmed that the CN bond formation results from the cross‐coupling of N‐chlorocarbamate with the aryl–rhodium(III) complex. Yet, the mechanistic details regarding the CN bond formation remain unclear; pathways involving 1,2‐aryl migration and rhodium(V)– nitrene are plausible.
Simultaneous In Situ Measurement of Oxygen Consumption and Product Formation during Oxidation of Cyclohexane
Authors: Fräulin Christine , Rinke Günter , Dittmeyer Roland , Waters Gerrit , Nilles Michael 
Published: March 2014

AbstractEine auf der Laser‐Raman‐Spektroskopie basierende, ortsaufgelöste In‐situ‐Messtechnik mit hoher Nachweisempfindlichkeit wurde entwickelt, um Flüssigphasenreaktionen unter definierten Bedingungen in einem Mikrokanalreaktor zu untersuchen. Dieses Verfahren erlaubt die gleichzeitige Messung der Konzentrationen von gelöstem molekularen Sauerstoff und Oxidationsprodukten in organischen Flüssigkeiten während der Reaktion. Es kann als neues Werkzeug für detaillierte kinetische Untersuchungen verwendet werden. Hier werden erste Ergebnisse der Untersuchungen der unkatalysierten Cyclohexanoxidation vorgestellt.
Accurate Prediction of IrH Bond Dissociation Enthalpies by Density Functional Theory Methods
Authors: Zhou Yi , Liu Dingjia , Fu Yao , Yu Haizhu , Shi Jing 
Published: March 2014

AbstractThe iridium hydride complexes have been extensively used in organic reactions, such as oxidation and hydrogenation reactions. In many of these reactions, the dissociation or formation of IrH bond plays an important role in determining the overall reaction rates and yields. In the present study, the accuracy of different theoretical methods for prediction of IrH bond strengths has been examined on the basis of the previously reported IrH BDEs of 17 different complexes. Comparing the performance of different DFT functionals (e.g. B3LYP, TPSS, M06), different basis sets (including the different effective core potentials (ECP) on Ir and I atoms, and the total electron basis sets on the other atoms), and different solvation models (SMD, CPCM, and IEFPCM) in solution phase single point calculations, we found that the gas‐phase calculation with TPSS/(LanL2DZ: 6‐31G(d)) method is relatively more accurate than the other gas‐phase calculation methods, and can well simulate the IrH BDEs in low‐polarity solvents (such as chlorobenzene and dichloroethane). Finally, efforts were put in analyzing the structure‐activity relationships between the ligand structure (around Ir center) and the IrH BDEs. We wish the present study could benefit future studies on the Ir‐H complexes involved organic reactions.
Batchsubmit: a high‐volume batch submission system for earthquake engineering simulation
Authors: Mohan Anup , Hacker Thomas , Rodgers Gregory P. , Islam Tanzima 
Published: March 2014

SUMMARYNetwork for Earthquake Engineering Simulation (NEES) is a network of 14 earthquake engineering labs distributed across the USA. As a part of the NEES effort NEESComm operates a comprehensive cyberinfrastructure that consists of the NEEShub and the NEES Project Warehouse. NEESComm provides consistent access to several high performance computing (HPC) venues. These venues include Extreme Science and Engineering Discovery Environment, the Open Science Grid, Purdue Supercomputers, and NEEShub servers. In this paper, we describe the system we developed, batchsubmit, which allows NEES researchers to make use of all these venues through the NEEShub science gateway. Copyright © 2014 John Wiley & Sons, Ltd.
High‐Resolution Tracking of Single‐Molecule Diffusion in Membranes by Confocalized and Spatially Differentiated Fluorescence Photon Stream Recording
Authors: Sahl Steffen J. , Leutenegger Marcel , Hell Stefan W. , Eggeling Christian 
Published: March 2014

AbstractThe performance of a method is assessed which allows for the spatiotemporal tracking of single dye‐labeled molecules during two‐dimensional (2D) diffusional transits through the focal area of a modified confocal microscope. In addition to facilitating the observation of molecular diffusion paths at the shot‐noise limit of bright organic emitters with spatial and temporal precisions of ∼10–20 nm and <0.5 ms, respectively, the direct access to the complete stream of detected photons is beneficial for characterizing nanoscale details such as transient pausing (binding). We discuss technical aspects of this approach, along with results from its application to measuring lipid membrane dynamics in live mammalian cells. Presented topics include a discussion of the advantages of the single‐photon collection mode and instrument as well as computational considerations for the localization process. A proof‐of‐principle experiment shows that optical nanoscopy by stochastic single‐molecule switching and position readout could be implementable in parallel with such fast molecular tracking. This would allow direct access to contextual imaging data of local cytoskeletal structural elements or localized longer‐lived protein assemblies.
Solution‐Processed Mesoscopic Bi2S3:Polymer Photoactive Layers
Authors: MacLachlan Andrew J. , O'Mahony Flannan T. F. , Sudlow Anna L. , Hill Michael S. , Molloy Kieran C. , Nelson Jenny , Haque Saif A. 
Published: March 2014

AbstractThe fabrication of solution‐processed nontoxic mesoporous Bi2S3 structures is demonstrated and the suitability of these structures for use in hybrid solar cells investigated. Mesoporous Bi2S3 electrodes are prepared via thermal decomposition of a thin film composed of a bismuth xanthate single source precursor. The resultant Bi2S3 films are made up of regular needles with approximate dimensions of 50×500 nm, as confirmed by scanning electron microscopy (SEM). The crystallinity of the Bi2S3 is found to be dependent on the annealing temperature, as determined by X‐ray diffraction. The porous Bi2S3 films are infiltrated with the hole conductor P3HT to generate novel hybrid films, and laser‐based transient absorption spectroscopy is used to interrogate the charge‐separation reaction at the resulting Bi2S3/P3HT heterojunction. Specifically, optical excitation of the hybrid films results in efficient and long‐lived charge separation (microsecond to millisecond timescale), thereby rendering such films suitable for the development of novel low‐cost solar‐energy conversion devices.
CO2 Recycling: A Key Strategy to Introduce Green Energy in the Chemical Production Chain
Authors: Perathoner Siglinda , Centi Gabriele 
Published: March 2014

AbstractThe introduction of renewable energy in the chemical production chain is a key strategic factor both to realize a sustainable, resource‐efficient, low‐carbon economy and society and to drive innovation and competiveness in the chemical production. This Concept discusses this concept in terms of motivations, perspectives, and impact as well as technical barriers to achieve this goal. It is shown how an important element to realize this scenario is to foster the paths converting carbon dioxide (CO2) into feedstock for the chemical/process industry, which is one of the most efficient methods to rapidly introduce renewable energy into the chemical production chain. Some of the possible options to proceed in this direction are discussed, with focus on the technical barriers and enabling factors such as catalysis. The tight interconnection between CO2 management and the use of renewable energy is evidenced.
Affine Projection‐Type Blind Multiuser Detection with Block Length Control under the Multipath Environment
Authors: Tanabe Nari , Takezawa Masatoshi , Furukawa Toshihiro 
Published: March 2014

SUMMARYThis paper proposes affine‐projection blind multiuser detection with block length control for improvement of convergence speed in DS‐CDMA (direct sequence code division multiple access) systems in a multipath environment. The traditional method of controlling the block length is discussed for the situation in which the desired signal of the system is given. But due to the difficulty of the application of the above method to blind multiuser detection, some suitable improvements are performed in the proposed method. These give the proposed method advantages over the traditional detectors.
Push–Pull‐Type Purine Nucleoside‐Based Fluorescent Sensors for the Selective Detection of Pd2+ in Aqueous Buffer
Authors: Li Jian‐Ping , Wang Hui‐Xuan , Wang Hai‐Xia , Xie Ming‐Sheng , Qu Gui‐Rong , Niu Hong‐Ying , Guo Hai‐Ming 
Published: March 2014

AbstractPush–pull‐type purine nucleoside‐based fluorescent sensor L1 bearing a chelating N,N‐bis(2‐pyridylmethyl)amine group at the C6 position was designed and synthesized. Sensor L1 showed clear and selective detection of Pd2+ in aqueous buffer, and it is the first “on–off”‐type purine nucleoside‐based fluorescent sensor for Pd2+.
Uranium accumulation and toxicity in the green alga Chlamydomonas reinhardtii is modulated by pH
Authors: Lavoie Michel , Sabatier Sébastien , Garnier-Laplace Jacqueline , Fortin Claude 
Published: March 2014

Abstract

The effects of pH on metal uptake and toxicity in aquatic organisms are currently poorly understood and remain an evolving topic in studies about the biotic ligand model (BLM). In the present study, the authors investigated how pH may influence long-term (4 d) uranium (U) accumulation and chronic toxicity in batch cultures of the freshwater green alga Chlamydomonas reinhardtii. The toxicity expressed as a function of the free uranyl ion was much greater at pH 7 (effective concentration, 50% [EC50] = 1.8 × 10−9 M UO22+) than at pH 5 (EC50 = 1.2 × 10−7 M UO22+). The net accumulation rate of U in algal cells was much higher at pH 7 than at pH 5 for the same free [UO22+], but the cells exposed at pH 5 were also more sensitive to intracellular U than the cells at pH 7 with EC50s of 4.0 × 10−15 and 7.1 × 10−13 mol of internalized U cell−1, respectively. The higher cellular sensitivity to U at pH 5 than at pH 7 could be explained partly by the increase in cytosolic U binding to algal soluble proteins or enzymes at pH 5 as observed by subcellular fractionation. To predict U accumulation and toxicity in algae accurately, the important modulating effects of pH on U accumulation and U cellular sensitivity should be considered in the BLM. Environ Toxicol Chem 2014;33:1372–1379. © 2014 SETAC
HMTP: Multipath transport protocol for multihoming wireless erasure networks
Authors: Hwang Younghak , Saha Abhijit , Choi Hanbit , Lim Hyuk , Obele Brownson O. 
Published: March 2014

AbstractThis paper proposes a fountain‐code‐based multipath transport protocol, called heterogeneous multipath transport protocol (HMTP), and evaluates its performance. HMTP improves the throughput performance and path utilisation of multihoming wireless erasure networks. It solves the receive buffer blocking problem and eliminates the need for retransmissions and in‐order packet delivery, both of which severely degrade the performance of existing multipath transport protocols in multihoming networks. The encoding and decoding algorithms of HMTP are based on efficient and computationally inexpensive coding algorithms such as LT codes. To minimise the fountain encoding/decoding overhead, complexity and computational cost while ensuring the desired decoding performance, the appropriate values of the parameters of the LT codes are determined. We implement and extensively evaluate the performance of HMTP using both NS‐2 simulator and an 802.11 wireless local area network laboratory test bed. Our simulations and experimental results show that HMTP significantly outperforms the concurrent multipath transfer stream control transmission protocol, especially in multihoming 802.11 wireless local area networks. Copyright © 2014 John Wiley & Sons, Ltd.
Survey of volatile substances in kitchen utensils made from acrylonitrile–butadiene–styrene and acrylonitrile–styrene resin in Japan
Authors: Abe Yutaka , Yamaguchi Miku , Mutsuga Motoh , Kawamura Yoko , Akiyama Hiroshi 
Published: March 2014

AbstractResidual levels of 14 volatile substances, including 1,3‐butadiene, acrylonitrile, benzene, ethylbenzene, and styrene, in 30 kitchen utensils made from acrylonitrile–butadiene–styrene resin (ABS) and acrylonitrile–styrene resin (AS) such as slicers, picks, cups, and lunch boxes in Japan were simultaneously determined using headspace gas chromatography/mass spectroscopy (HS‐GC/MS). The maximum residual levels in the ABS and AS samples were found to be 2000 and 2800 μg/g of styrene, respectively. The residual levels of 1,3‐butadiene ranged from 0.06 to 1.7 μg/g in ABS, and three of 15 ABS samples exceeded the regulatory limit for this compound as established by the European Union (EU). The residual levels of acrylonitrile ranged from 0.15 to 20 μg/g in ABS and from 19 to 180 μg/g in AS. The levels of this substance in seven ABS and six AS samples exceeded the limit set by the U.S. Food and Drug Administration (FDA). Furthermore, the levels of acrylonitrile in three AS samples exceeded the voluntary standard established by Japanese industries. These results clearly indicate that the residual levels of some volatile compounds are still high in ABS and AS kitchen utensils and further observations are needed.