bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Characterization of DNA Double Strand Breaks with Tip‐Enhanced Raman Scattering
Authors: Lipiec Ewelina , Sekine Ryo , Bielecki Jakub , Kwiatek Wojciech M. , Wood Bayden R. 
Published: November 2013

AbstractDNA double strand breaks (DSBs) are deadly lesions that can lead to genetic defects and cell apoptosis. Techniques that directly detect DNA DSBs include scanning electron microscopy, atomic force microscopy (AFM), and fluorescence based approaches. While these techniques can be used to identify DSBs they provide no information on the molecular events occurring at the break. Tip‐enhanced Raman scattering (TERS) can provide molecular information from DNA at the nanoscale and in combination with AFM provides a new way to visualize and characterize the molecular structure of DSBs. DSBs result from cleavage at the 3’‐ and 5’‐bonds of deoxyribose upon exposure to UVC radiation based on the observation of POH and methyl/methylene deformation modes enhanced in the TERS spectra. It is hypothesized that strand fragments are hydrogen‐terminated at the lesion, indicating the action of free radicals during photon exposure.
Accelerated Self‐Replication under Non‐Equilibrium, Periodic Energy Delivery
Authors: Zhang Rui , Walker David A. , Grzybowski Bartosz A. , Olvera de la Cruz Monica 
Published: November 2013

AbstractSelf‐replication is a remarkable phenomenon in nature that has fascinated scientists for decades. In a self‐replicating system, the original units are attracted to a template, which induce their binding. In equilibrium, the energy required to disassemble the newly assembled copy from the mother template is supplied by thermal energy. The possibility of optimizing self‐replication was explored by controlling the frequency at which energy is supplied to the system. A model system inspired by a class of light‐switchable colloids was considered where light is used to control the interactions. Conditions under which self‐replication can be significantly more effective under non‐equilibrium, cyclic energy delivery than under equilibrium constant energy conditions were identified. Optimal self‐replication does not require constant energy expenditure. Instead, the proper timing at which energy is delivered to the system is an essential controllable parameter to induce high replication rates.
Influence of room‐temperature‐stretching technology on the crystalline morphology and microstructure of PVDF hard elastic film
Authors: Lei Caihong , Hu Bing , Xu Ruijie , Cai Qi , Shi Wenqiang 
Published: November 2013

ABSTRACTThe crystalline morphology and microstructure during stretching of polyvinylidene fluoride hard elastic film under room temperature was followed using wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). It was found that an endotherm plateau from the contribution of some new crystals formed during annealing appeared and some thinner lamellae existed in the annealed film. During stretching, the endotherm plateau disappeared and those thinner lamellae transformed into β‐phase. At the same time, some initial pores were observed. With increasing stretching ratio from 20 to 100%, the β‐phase content increased, whereas within the strain rate range of 0.003–0.034 s−1, its content was least under 0.017 s−1. During stretching, lamellae separation, crystalline morphology transformation and disappearance of grown crystals formed by annealing coexisted. From the viewpoint of pore initiation, less crystalline morphology transformation was beneficial for the lamellae separation. Higher stretching ratio resulted in the breakage of separated lamellae. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40077.
Hydrogel composites based on linear low‐density polyethylene‐g‐poly (acrylic acid)/Kaolin or halloysite nanotubes
Authors: Irani Maryam , Ismail Hanafi , Ahmad Zulkifli 
Published: November 2013

ABSTRACTTwo series of superabsorbent hydrogel composites were prepared using waste linear low‐density polyethylene, acrylic acid, and two types of clays including kaolin and halloysite nanotube (HNT) through emulsion polymerization. The effects of the clay content on Water absorbency were investigated to obtain a high swelling capacity. The prepared samples were characterized using FTIR, SEM, thermogravimetric analysis, XRD, solid‐state 13C Nuclear Magnetic Resonance spectroscopy, and 29Si NMR. SEM characterization of the samples showed that the hydrogel composites have more pores and a higher swelling ratio than the clay‐free hydrogels. The hydrogel composite containing kaolin had higher water absorbency compared to the hydrogel composites with HNT. The swelling behavior of the hydrogel composite was investigated in various saline solutions. The hydrogel composite containing 5 wt % kaolin had the highest water absorbency (760 g/g in distilled water). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40101.
Largely improved crystallization behavior and thermal stability of poly(L‐lactide) via the synergistic effects of graphene oxide and carbon nanotubes
Authors: Chen Hai‐Ming , Shao Li‐Na , Shen Ying , Yang Jing‐Hui , Huang Ting , Zhang Nan , Wang Yong , Zhang Chao‐liang 
Published: November 2013

ABSTRACTGraphene oxide (GO) and carbon nanotubes (CNTs) and their compound were introduced into semicrystalline poly(l‐lactide) (PLLA) to prepare the corresponding binary and/or ternary nanocomposites, respectively. The dispersion states of nanofillers in different nanocomposites were investigated using UV‐Vis spectroscopy, scanning electron microscopy (SEM) and rheological measurement. The results showed that when GO and CNTs were simultaneously present in the PLLA matrix, good dispersion states of both GO and CNTs could be achieved and the ternary nanocomposites exhibited percolated network structure. The effects of different nanofillers on the crystallization behavior of PLLA matrix were comparatively investigated under the different crystallization conditions including melt crystallization process (nonisothermal and isothermal crystallization from the melt) and cold crystallization (crystallization occurring from an amorphous state during the annealing process). The results showed that GO and CNTs exhibited apparent synergistic effects in improving crystallization ability and enhancing crystallinity of PLLA matrix. Study on the thermal stability of nanocomposites showed that the presence of nanofillers greatly improved the thermal stability of PLLA matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40143.
Chemical Variability and Antioxidant Activity of Limbarda crithmoides L. Essential Oil from Corsica
Authors: Andreani Stéphane , De Cian Marie‐Cecile , Paolini Julien , Desjobert Jean‐Marie , Costa Jean , Muselli Alain 
Published: November 2013

AbstractThe chemical compositions of 25 Corsican Limbarda crithmoides ssp. longifolia essential oils were investigated for the first time using GC‐FID, GC/MS, and NMR analyses. Altogether, 65 compounds were identified, accounting for 90.0–99.3% of the total oil compositions. The main components were p‐cymene (1; 15.1–34.6%), 3‐methoxy‐p‐cymenene (4; 11.8–28.5%), 2,5‐dimethoxy‐p‐cymenene (5; 5.9–16.4%), thymol methyl ether (6; 1.3–14.9%), α‐phellandrene (2; 0.9–11.9%), and α‐pinene (3; 0.2–13.4%). The chemical variability of the Corsican oil samples was studied using multivariate statistical analysis, which allowed the discrimination of two main clusters. A direct correlation between the water salinities of the plant locations and the chemical compositions of the L. crithmoides essential oils was evidenced. Indeed, essential oils rich in 1 (30.4–34.6%) were found in samples growing in the wetlands of the southern oriental coast, which exhibit high salinity levels (24.4±0.2–33.9±0.2 ppt), and essential oils with lower contents of 1 (15.1–27.3%) were isolated form samples growing in the wetlands of northern Corsica, which exhibit lower salinity levels (10.90±0.20–15.47±0.15 ppt). The antioxidant potential of L. crithmoides essential oil was also investigated, by assessing the DPPH.‐ and ABTS.+‐scavenging activities and the reducing power of ferric ions, and was found to be interesting. Moreover, using bioassay‐guided fractionation of the essential oil, a higher antioxidant activity was obtained for the oxygenated fraction and both ester and alcohol subfractions.
Pressure‐Dependent Effect of Hydrogen Adsorption on Structural and Electronic Properties of Pt/γ‐Al2O3 Nanoparticles
Authors: Mistry Hemma , Behafarid Farzad , Bare Simon R. , Roldan Cuenya B. 
Published: November 2013

AbstractUnderstanding the interaction of hydrogen with subnanometer platinum nanoparticles (NPs) under industrially relevant conditions is of great importance to heterogeneous catalysis. In this work, we investigate the pressure‐dependent changes in hydrogen coverage on size‐ and shape‐selected Pt/γ‐Al2O3 NPs by in situ X‐ray absorption near‐edge structure (XANES) analysis. Difference XANES calculations revealed an increase in the H/Pt ratio from 1.9 to 2.5 upon increasing the hydrogen pressure from 1 to 21 bar at room temperature (1 bar=100 kPa). In addition, extended X‐ray absorption fine structure measurements of the local geometrical structure showed changes in PtPt bond length and coordination number, revealing a morphological transformation in the NPs from a 2 D to a 3 D shape under increasing H2 pressure at room temperature. Such shape evolution leads to a decrease in the NP–support contact area and is thus expected to affect the NP stability against coarsening.
Bifunctional (Cyclopentadienone)Iron–Tricarbonyl Complexes: Synthesis, Computational Studies and Application in Reductive Amination
Authors: Moulin Solenne , Dentel Hélène , Pagnoux‐Ozherelyeva Anastassiya , Gaillard Sylvain , Poater Albert , Cavallo Luigi , Lohier Jean‐François , Renaud Jean‐Luc 
Published: November 2013

AbstractReductive amination under hydrogen pressure is a valuable process in organic chemistry to access amine derivatives from aldehydes or ketones. Knölker’s complex has been shown to be an efficient iron catalyst in this reaction. To determine the influence of the substituents on the cyclopentadienone ancillary ligand, a series of modified Knölker’s complexes was synthesised and fully characterised. These complexes were also transformed into their analogous acetonitrile iron–dicarbonyl complexes. Catalytic activities of these complexes were evaluated and compared in a model reaction. The scope of this reaction is also reported. For mechanistic insights, deuterium‐labelling experiments and DFT calculations were undertaken and are also presented.
Mesoporous Anatase TiO2 Nanorods as Thermally Robust Anode Materials for Li‐Ion Batteries: Detailed Insight into the Formation Mechanism
Authors: Seisenbaeva Gulaim A. , Nedelec Jean‐Marie , Daniel Geoffrey , Tiseanu Carmen , Parvulescu Vasile , Pol Vilas G. , Abrego Luis , Kessler Vadim G. 
Published: November 2013

AbstractUniformly mesoporous and thermally robust anatase nanorods were produced with quantitative yield by a simple and efficient one‐step approach. The mechanism of this process was revealed by insertion of Eu3+ cations from the reaction medium as luminescent probes. The obtained structure displays an unusually high porosity, an active surface area of about 300 m2g−1 and a specific capacity of 167 mA h g−1 at a C/3 rate, making it attractive as an anode electrode for Li‐ion batteries. An additional attractive feature is its remarkable thermal stability; heating to 400 °C results in a decrease in the active surface area to a still relatively high value of 110 m2 g−1 with conservation of open mesoporosity. Thermal treatment at 800 °C or higher, however, causes transformation into a non‐porous rutile monolith, as commonly observed with nanoscale titania.
Control of limit cycle oscillations in a multiple‐sampled digitally controlled buck converter
Authors: Bradley Mark , Alarcón Eduard , Feely Orla 
Published: November 2013

SummaryDigital control in switching power converters has been proposed and researched in recent years. However, one of the problems which arise in these circuits is that of quantization‐induced limit cycle oscillations, which are generally considered to be undesirable. In this work, we investigate the addition of new control terms in the feedback loop of the system, in order to actively prevent these limit cycles from occurring. Firstly, the addition of a sinusoidal signal is considered, and then a more complicated signal which focuses on interrupting how the system switches between duty cycle levels is presented. The methods are effective in removing the limit cycle oscillations which arise in the system. Copyright © 2013 John Wiley & Sons, Ltd.
Hemin Functionalized Multiwalled Carbon Nanotubes as a Matrix for Sensitive Electrogenerated Chemiluminescence Cholesterol Biosensor
Authors: Wu Xiaoping , Chai Yaqin , Yuan Ruo , Chen Shihong , Zhang Meihe , Zhang Juanjuan 
Published: November 2013

AbstractBased on hemin‐MWCNTs nanocomposite and hemin‐catalyzed luminol‐H2O2 reaction, a sensitive electrogenerated chemiluminescence (ECL) cholesterol biosensor was proposed in this paper. Firstly, hemin‐MWCNTs was prepared via π–π stacking and modified on the surface of GCE. Subsequently, cholesterol oxidase (ChOx) was adsorbed on the modified electrode to achieve a cholesterol biosensor. Hemin‐MWCNTs nanocomposite provided the electrode with a large surface area to load ChOx, and endowed the nanostructured interface on the electrode surface to enhance the performance of biosensor. The biosensor responded to cholesterol in the linear range from 0.3 µM to 1.2 mM with a detection limit of 0.1 µM (S/N=3).
On sparse sensing and sparse sampling of coded signals at sub‐Landau rates
Authors: Peleg Michael , Shamai Shlomo 
Published: November 2013

ABSTRACTAdvances in information‐theoretic analysis of sparse sampling of continuous uncoded signals at sampling rates exceeding the Landau rate were reported in recent works. This work examines sparse sampling of coded signals at sub‐Landau sampling rates. It is shown that with coded and with discrete signals, the Landau condition may be relaxed, and the sampling rates required for signal reconstruction and for support detection can be lower than the effective bandwidth. Equivalently, the number of measurements in the corresponding sparse sensing problem can be smaller than the support size. Tight bounds on information rates and on signal and support detection performance are derived for the Gaussian sparsely sampled channel and for the frequency‐sparse channel using the context of state dependent channels. Support detection results are verified by a simulation. When the system is high‐dimensional, the required signal to noise ratio is shown to be finite but high and rising with decreasing sampling rate; in some practical applications, it can be lowered by reducing the a‐priory uncertainty about the support, for example, by concentrating the frequency support into a finite number of subbands. The sub‐Landau sampling rates are analysed also in large systems with discrete signal constellations replacing the coding. Copyright © 2013 John Wiley & Sons, Ltd.
Double Asymmetric Induction in the Synthesis of Enantiomeric α‐Aminophosphonic Acids Mediated by Sulfinimines
Authors: Łyżwa Piotr 
Published: November 2013

ABSTRACTA double asymmetric induction in the synthesis of α‐aminophosphonic acids is described. It involves the nucleophilic addition of anions of enantiomeric dimenthyl phosphites to both (+)‐(S)‐ and (–)‐(R)‐enantiomers of N‐(p‐tolylsulfinyl)benzaldimine and subsequent acidic hydrolysis of the adducts formed. The match and mismatch effects were observed.
Copper‐Catalyzed One‐Pot Synthesis of Functionalized Pyrroles from Sulfonyl Azides, Alkynes, and (p‐Toluenesulfonyl)methyl Isocyanide
Authors: Yavari Issa , Nematpour Manijeh 
Published: November 2013

AbstractKetenimine intermediates generated by the addition of copper acetylides to sulfonyl azides are trapped by (p‐toluenesulfonyl)methyl isocyanide (TsCH2NC), in the presence of Et3N, to afford functionalized pyrroles in moderate‐to‐good yields.
Interaction between silver nanoparticles of 20 nm (AgNP20) and human neutrophils: induction of apoptosis and inhibition of de novo protein synthesis by AgNP20 aggregates
Authors: Poirier Michelle , Simard Jean‐Christophe , Antoine Francis , Girard Denis 
Published: November 2013

ABSTRACTCytotoxic and proinflammatory properties of silver nanoparticles (AgNPs) have been reported in few studies but the direct interaction between AgNPs and neutrophils, which play a key role in inflammation, has never been documented. Here, we examined the role of AgNPs with a starting size of 20 nm (AgNP20) in human neutrophils. Using dynamic light scattering for the characterization of NPs suspended under identical conditions to those used for in vitro experiments, we found that, at 10 µg ml–1, 92% of AgNP20 possess a diameter of 17.1 nm but, at 100 µg ml–1, a tri‐modal size distribution with large aggregates was observed (> 500 nm). Neutrophil cell size increased when treated with AgNP20 and transmission electronic microscopy experiments revealed that AgNP20 can rapidly interact with the cell membrane, penetrate neutrophils, localize in vacuole‐like structures, and be randomly distributed in the cytosol after 24 h. Treatment with 100 µg ml–1 AgNP20 for 24 h (but not 10 µg ml–1) increased the neutrophil apoptotic rate and inhibited de novo protein synthesis. We conclude that AgNP20 induced apoptosis and can act as potent inhibitors of de novo protein synthesis at 100, but not 10 µg ml–1 in human neutrophils. Copyright © 2013 John Wiley & Sons, Ltd.
Perceptions of Age and Creativity in the Workforce
Authors: Chan Kara , Hui Anna , Cheng Sheung‐Tak , Ng Yu Leung 
Published: November 2013

AbstractAs the workforce ages it becomes important to examine if there is misperception of creativity and age in work contexts. A laboratory experiment examined perceptions of the creativity of a team with both young and old workers and of a team composed entirely of young workers. Scripted videos portrayed such teams engaged in designing an outdoor advertising campaign. Altogether, 220 participants were randomly assigned to watch one of the video clips and complete a structured questionnaire. No significant differences were observed in the perceptions of the two teams' performance or of the quality of the resulting advertising proposal. In general, there was also no significant difference in the individual characteristics attributed to the four characters on the teams. However, participants aged 35 or above evaluated both teams and all four characters more favorably than participants aged 20–34.
The influence of divalent metal ions on low pH induced LacDNA structural changes as probed with UV resonance Raman spectroscopy
Authors: Muntean Cristina M. , Salehi Mohammad , Niebling Stephan , Walkenfort Bernd 
Published: November 2013

UV (275 nm) resonance Raman spectra of LacDNA 22‐mer duplex [d(TAATGTGAGTTAGCTCACTCAT) · d(ATGAGTGAGCTAACTCACATTA)], which contain protein binding sites within the E. coli lac promoter, were measured at two pH values (6.4 and 3.45) in the absence and presence of Mn2+ and Ca2+ metal ions, respectively. Also, the UV (275 nm) resonance Raman markers of the corresponding oligonucleotide d(TAATGTGAGTTAGCTCACTCAT) and of its complementary anti‐sense strand d(ATGAGTGAGCTAACTCACATTA) were established and tentatively assigned.Large changes in the UV (275 nm) resonance Raman spectra of LacDNA duplex were observed at pH 3.45 as compared with the corresponding spectrum at pH 6.4, in the absence of divalent metal ions and at low concentrations of Ca2+ ions, respectively. Major changes comprise: adenine protonation, GC base pair protonation, DNA bases unstacking and changes in the hydrogen bonding strength between the strands of different LacDNA complexes, respectively. Divalent metal ions (Mn2+ and Ca2+) were found to inhibit LacDNA protonation even at low concentrations. Manganese(II) ions are much more effective in this regard, as compared with calcium(II) ions. Binding of Mn2+ ions to N7 of guanine and, possibly, in a lesser extent to adenine was observed as judging from the difference Raman bands at 1315, 1354 and 1493 cm−1. Copyright © 2013 John Wiley & Sons, Ltd.
Precision Synthesis of Bio‐Based Acrylic Thermoplastic Elastomer by RAFT Polymerization of Itaconic Acid Derivatives
Authors: Satoh Kotaro , Lee Dong‐Hyung , Nagai Kanji , Kamigaito Masami 
Published: November 2013

Bio‐based polymer materials from renewable resources have recently become a growing research focus. Herein, a novel thermoplastic elastomer is developed via controlled/living radical polymerization of plant‐derived itaconic acid derivatives, which are some of the most abundant renewable acrylic monomers obtained via the fermentation of starch. The reversible addition–fragmentation chain‐transfer (RAFT) polymerizations of itaconic acid imides, such as N‐phenylitaconimide and N‐(p‐tolyl)itaconimide, and itaconic acid esters, such as di‐n‐butyl itaconate and bis(2‐ethylhexyl) itaconate, are examined using a series of RAFT agents to afford well‐defined polymers. The number‐average molecular weights of these polymers increase with the monomer conversion while retaining relatively narrow molecular weight distributions. Based on the successful controlled/living polymerization, sequential block copoly­merization is subsequently investigated using mono‐ and di‐functional RAFT agents to produce block copolymers with soft poly(itaconate) and hard poly(itaconimide) segments. The properties of the obtained triblock copolymer are evaluated as bio‐based acrylic thermoplastic elastomers.
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Dynamic Multi‐Phase, Multi‐Zone Modeling of Flash Separators for Highly Viscous Polymerization Processes
Authors: Pladis Prokopis , Baltsas Apostolos , Kanellopoulos Vasileios , Kiparissides Costas 
Published: November 2013

SummaryA multi‐phase, multi‐zone mathematical model is developed to describe the dynamic operation of an industrial high‐pressure flash separator for a ternary (Ethylene–Vinyl acetate–EVA) system. The proposed description of the high‐pressure separator can take into account the complex gas carry‐under and liquid droplets carry‐over phenomena occurring during the non‐equilibrium operation of the separator. Numerical simulations have been carried out to determine the effect of operating conditions on the dynamic operation and separation efficiency of a HPS unit operating in series with an industrial scale high‐pressure EVA autoclave. The proposed model is capable of simulating the dynamic operation of an industrial‐scale HPS over a wide range of operating conditions and EVA copolymer grades.