bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of a phosphorus/silicon hybrid and its synergistic effect with melamine polyphosphates on flame retardant polypropylene system
Authors: Huang Y. W. , Song M. L. , Ma J. J. , Lu Z. Y. , Yang J. X. , Cao K. 
Published: November 2012

AbstractA novel flame retardant (SDPS) containing POSi bands was synthesized by a condensation polymerization of diphenylhydroxysilane and spirocyclic pentaerythritol di(phosphate monochloride). The structure of SDPS was confirmed by Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H NMR). Limiting oxygen index (LOI) test showed that when loading 22.5 wt % SDPS and 7.5 wt % in polypropylene, LOI value markedly increased to 31.4% in comparison with PP/SDPS (30 wt %) and PP/MP (30 wt %) systems. Combusting experiment further proved a synergistic effect of SDPS and melamine polyphosphates (MP) in flame retarding of polypropylene. Thermogravimetric analysis (TGA) and FTIR‐TG results revealed that the synergistic effect was attributed to a catalyzed breaking down of POSi bands in the presence of MP, which acted as an acid catalyst, consequently leading to a facilitated char and silica forming process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Temperature and pH effects on the stability and rheological behavior of the aqueous suspensions of smart polymers based on N‐isopropylacrylamide, chitosan, and acrylic acid
Authors: do Nascimento Marques Nívia , Curti Priscila Schroeder , da Silva Maia Ana Maria , Balaban Rosangela de Carvalho 
Published: November 2012

AbstractThis study describes the stability and rheological behavior of suspensions of poly(N‐isopropylacrylamide) (PNIPAM), poly(N‐isopropylacrylamide)‐chitosan (PNIPAM‐CS), and poly(N‐isopropylacrylamide)‐chitosan‐poly(acrylic acid) (PNIPAM‐CS‐PAA) crosslinked particles sensitive to pH and temperature. These dual‐sensitive materials were simply obtained by one‐pot method, via free‐radical precipitation copolymerization with potassium persulfate, using N,N′‐methylenebisacrylamide as a crosslinking agent. Incorporation of the precursor materials into the chemical networks was confirmed by elementary analysis and infrared spectroscopy. The influence of external stimuli such as pH and temperature, or both, on particle behavior was investigated through rheological measurements, visual stability tests, and analytical centrifugation. The PNIPAM‐CS particles showed higher stability in acid and neutral media, whereas PNIPAM‐CS‐PAA particles were more stable in neutral and alkaline media, both below and above the lower critical solution temperature of PNIPAM (stability data). This is due to different interparticle interactions as well as those between the particles and the medium (also evidenced by rheological data), which were also influenced by the pH and temperature of the medium. Based on the results obtained, we found that the introduction of pH‐sensitive polymers to crosslinked PNIPAM particles not only produced dual‐sensitive materials but also allowed particle stability to be adjusted, making phase separation faster or slower, depending on the desired application. Thus, it is possible to adapt the material to different media. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Real‐Time Fluorescence Turn‐On Detection of Alkaline Phosphatase Activity with a Novel Perylene Probe
Authors: Chen Jian , Jiao Huping , Li Wenying , Liao Dongli , Zhou Huipeng , Yu Cong 
Published: November 2012

AbstractA tetracationic perylene probe (probe 2) was designed and synthesized. Probe 1 was used for the real‐time fluorescence turn‐on assay of alkaline phosphatase (ALP) activity and inhibitor screening. Probe 1 monomer fluorescence could be very efficiently quenched by ATP through the formation of an ATP/probe 1 complex. ALP triggered the degradation of ATP, the breakdown of the ATP/probe 1 complex, and the recovery of the probe 1 monomer fluorescence. In the presence of an ALP inhibitor, a decrease in fluorescence recovery was observed.
Enhancing the Photocatalytic Activity of Anatase TiO2 by Improving the Specific Facet‐Induced Spontaneous Separation of Photogenerated Electrons and Holes
Authors: Liu Chang , Han Xiguang , Xie Shuifen , Kuang Qin , Wang Xue , Jin Mingshang , Xie Zhaoxiong , Zheng Lansun 
Published: November 2012

AbstractRecently, it has been proven that directional flow of photogenerated charge carriers occurs on specific facets of TiO2 nanocrystals. Herein, we demonstrate that the photocatalytic activity of anatase TiO2 nanocrystals in both photoreduction and photooxidation processes can be enhanced by selectively depositing Pt nanoparticles on the {101} facets, which strengthens spontaneously surface‐induced separation between photogenerated electrons and holes in the photocatalysis process. An optimal ratio of the oxidative {001} facets to the reductive {101} facets exists with regard to the photocatalysis of the faceted TiO2 nanocrystals, and this is crucial for balancing the recombination and redox reaction rates of photogenerated electrons and holes. The present work might help us gain deeper insight into the relation between the specific surface of semiconductor photocatalysts and their photocatalytic activities and provides us with a new route to design photocatalysts with high photocatalytic activity.
Process model comparison and transferability across bioreactor scales and modes of operation for a mammalian cell bioprocess
Authors: Craven Stephen , Shirsat Nishikant , Whelan Jessica , Glennon Brian 
Published: November 2012

AbstractA Monod kinetic model, logistic equation model, and statistical regression model were developed for a Chinese hamster ovary cell bioprocess operated under three different modes of operation (batch, bolus fed‐batch, and continuous fed‐batch) and grown on two different bioreactor scales (3 L bench‐top and 15 L pilot‐scale). The Monod kinetic model was developed for all modes of operation under study and predicted cell density, glucose glutamine, lactate, and ammonia concentrations well for the bioprocess. However, it was computationally demanding due to the large number of parameters necessary to produce a good model fit. The transferability of the Monod kinetic model structure and parameter set across bioreactor scales and modes of operation was investigated and a parameter sensitivity analysis performed. The experimentally determined parameters had the greatest influence on model performance. They changed with scale and mode of operation, but were easily calculated. The remaining parameters, which were fitted using a differential evolutionary algorithm, were not as crucial. Logistic equation and statistical regression models were investigated as alternatives to the Monod kinetic model. They were less computationally intensive to develop due to the absence of a large parameter set. However, modeling of the nutrient and metabolite concentrations proved to be troublesome due to the logistic equation model structure and the inability of both models to incorporate a feed. The complexity, computational load, and effort required for model development has to be balanced with the necessary level of model sophistication when choosing which model type to develop for a particular application. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013
Improving the fermentation performance of saccharomyces cerevisiae by laccase during ethanol production from steam‐exploded wheat straw at high‐substrate loadings
Authors: Alvira Pablo , Moreno Antonio D. , Ibarra David , Sáez Felicia , Ballesteros Mercedes 
Published: November 2012

AbstractOperating the saccharification and fermentation processes at high‐substrate loadings is a key factor for making ethanol production from lignocellulosic biomass economically viable. However, increasing the substrate loading presents some disadvantages, including a higher concentration of inhibitors (furan derivatives, weak acids, and phenolic compounds) in the media, which negatively affect the fermentation performance. One strategy to eliminate soluble inhibitors is filtering and washing the pretreated material. In this study, it was observed that even if the material was previously washed, inhibitory compounds were released during the enzymatic hydrolysis step. Laccase enzymatic treatment was evaluated as a method to reduce these inhibitory effects. The laccase efficiency was analyzed in a presaccharification and simultaneous saccharification and fermentation process at high‐substrate loadings. Water‐insoluble solids fraction from steam‐exploded wheat straw was used as substrate and Saccharomyces cerevisiae as fermenting microorganism. Laccase supplementation reduced strongly the phenolic content in the media, without affecting weak acids and furan derivatives. This strategy resulted in an improved yeast performance during simultaneous saccharification and fermentation process, increasing significantly ethanol productivity. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013
Optimal projection for transcatheter aortic valve implantation determined from the reference projection angles
Authors: Cockburn James , Trivedi Uday , Belder Adam de , Hildick‐Smith David 
Published: November 2012

AbstractIntroduction: An optimal fluoroscopic working view projection (OP) with all three aortic sinuses aligned is crucial during trans‐catheter aortic valve implantation (TAVI). The aim of this study was to identify simple reference projection angles, which would act as a starting point for the operator to help determine OP for patients undergoing TAVI. Methods: During the period under consideration, 50 patients underwent TAVI. Procedural data and outcomes were collected prospectively on a dedicated database. Optimal angiographic deployment angles were achieved for all patients by starting in an anteroposterior caudal 15 degrees projection and then adjusting according to the initial image, with multiple small volume contrast injections undertaken to determine when all three aortic cusps were aligned (OP). Results: OP angles for the 50 cases were plotted on a graph. After normality testing confirmed that all angles were normally distributed, regression analysis enabled a regression line to be calculated. The equation for the regression line was defined as cranial/caudal intercept −16.4 ± 1.5 (SE of the coefficient), P < 0.0001, slope of regression line LAO/RAO + 0.53 ± 0.1 (SE of the coefficient SE), P < 0.0001). Conclusions: As the regression line and its equation represents an acceptable estimate of the true relationship between Cranial/Caudal and LAO/RAO, to determine OP while remaining close to the regression line we suggest starting in LAO = 8.9, Caudal = −11.4 (which represent the mean values of these two variables), and then increasing the caudal angle by approximately 0.5 degrees for every increase of 1 degree of the LAO angle or decreasing the caudal angle by 0.53 degrees for every decrease of 1 degree in LAO until all three aortic sinuses are in line which represents OP. © 2012 Wiley Periodicals, Inc.
On the Way to Cofactor Regeneration in Nanopores: Tailoring Porous Materials for Glucose‐6‐phosphate Dehydrogenase Immobilization
Authors: Fried Dorothee I. , Tropp Kristin , Fröba Michael 
Published: November 2012

AbstractMesoporous cellular siliceous foams (MCF) and hierarchical porous carbons are prepared and functionalized to tailor the interactions between glucose‐6‐phosphate dehydrogenase (G6PDH) from Leuconostoc mesenteroides and the surface of the porous supports. The electrostatic properties of the surfaces were investigated with zeta potential titrations and the porosity was determined by gas adsorption and mercury porosimetry. The hydrophobicity of the porous carbons even after oxidation resulted in low uptake, high leaching, and low activities. In contrast, high loading densities of up to 110 mg g−1 support were observed with aminopropyl‐modified MCF as a result of strong electrostatic interactions. G6PDH was used here to produce the cofactor NADPH under conversion of Glucose‐6‐phosphate to 6‐phosphogluconate (Scheme 2). The activity of the protein in this reaction was almost retained and high thermal and storage stabilities have been observed compared to the free enzyme. These results show that an effective conversion of the substrate Glucose‐6‐phosphate coupled to a production of the cofactor NADPH from NADP+ was achieved by successful immobilization of G6PDH on MCF.
Aerobic Oxidation of Thiols Catalyzed by Copper Nanoparticles Supported on Diamond Nanoparticles
Authors: Dhakshinamoorthy Amarajothi , Navalon Sergio , Sempere David , Alvaro Mercedes , Garcia Hermenegildo 
Published: November 2012

AbstractAfter purification by Fenton treatment, commercial diamond nanoparticles (NPs) are a suitable solid support for the deposition of Cu nanoparticles. Heating at 500 °C under hydrogen proved to be a convenient annealing process for Fenton‐purified diamond NPs that decreased the population of surface carboxylic acid groups and lead to samples with average Cu particle sizes of 3–4 nm. The samples of Cu NPs supported on diamond NPs have been characterized by IR and X‐ray photoelectron spectroscopy, as well as XRD and TEM. It was concluded that the samples contained Cu0 as well as CuI and CuII species. The resulting diamond‐supported Cu NPs were highly active for the selective aerobic oxidation of aromatic thiols to the corresponding disulfides, whereas aliphatic thiols exhibited much lower reactivity because of some poisoning and catalyst deactivation produced by aliphatic thiols. The Cu catalysts used for thiophenol oxidation could be reused in four consecutive runs with 4 % of decrease in the catalytic activity. This Cu catalyst exhibited similar catalytic activity, but is considerably more affordable, as an analogous diamond‐supported Au catalyst.
Highly Selective 1,4‐ and 1,6‐Addition of P(O)H Compounds to p‐Quinones: A Divergent Method for the Synthesis of C‐ and O‐Phosphoryl Hydroquinone Derivatives
Authors: Xiong Biquan , Shen Ruwei , Goto Midori , Yin Shuang‐Feng , Han Li‐Biao 
Published: November 2012

AbstractThe reaction of P(O)H compounds with p‐quinones could proceed through either 1,4‐ or 1,6‐addition pathways by employing different additives to selectively give the corresponding C‐ and O‐phosphoryl hydroquinone derivatives in good yields. Oxidative double 1,4‐addition of P(O)H compounds to p‐quinones was also achieved by tuning the solvent, affording a facile synthesis of bis‐substituted hydroquinones with phosphorus functionality. Further studies on these reactions by using optically active H‐phosphinates showed that all addition reactions took place stereospecifically with retention of configuration at the phosphorus center. The findings lead to the establishment of a divergent method for the synthesis of C‐ and O‐phosphoryl hydroquinone derivatives from easily available P(O)H compounds.
Development of the Travelling Wave Bioreactor – A Concept Study
Authors: Kaiser Stephan C. , Kraume Matthias , Eibl Dieter 
Published: November 2012

AbstractThis study presents the concept of the travelling wave single‐use bioreactor, based on an orbitally shaken, annular‐shaped vessel. A numerical model was developed for early design studies in order to reduce the number of prototypes. The flow characteristics in two different vessel shapes were investigated. It was shown that the orbital motion combined with the toroidal shape of the bioreactor create the desired wave characteristics in the contents of the vessel.
Solvatochromism and Nonradiative Decay of Intramolecular Charge‐Transfer Excited States: Bands‐of‐Energy Model, Thermodynamics, and Self‐Organization
Authors: Pavlovich Vladimir S. 
Published: November 2012

AbstractThe fluctuations of orientation and induction interactions in solution and their impact on the broadening of absorption and fluorescence spectra are considered in terms of a bands‐of‐energy model. Also covered is the application of principles of thermodynamics and self‐organization of systems for calculation of solvatochromic shift, among them a component owing to the work on electronic polarization of solvent at the instant of electronic transition in the solute. The findings on solvatochromic shift and spectral broadening open the way to the calculation of solvent effects on the rate constant of nonradiative transitions. As demonstrated herein for 15 fluorophores, the novel theory of nonradiative decay of the intramolecular charge‐transfer excited states is carried out for dyes and organic compounds of different nature, both for polar and nonpolar media.
Effect of NaCl on ESPT‐Mediated FRET in a CTAC Micelle: A Femtosecond and FCS Study
Authors: Mandal Amit Kumar , Ghosh Shirsendu , Das Atanu Kumar , Mondal Tridib , Bhattacharyya Kankan 
Published: November 2012

AbstractFemtosecond upconversion, single‐molecule fluorescence resonance energy transfer (sm‐FRET) and fluorescence correlation spectroscopy (FCS) are applied to study the competition between excited‐state proton transfer (ESPT) and FRET [to rhodamine 6G (R6G)] of 8‐hydroxypyranine‐1,3,6‐trisulfonate (HPTS) in cetyltrimethylammonium chloride (CTAC) micelles. Pyranine exhibits dual emission atλem=430 nm for ROH and 520 nm for RO−. The absorption spectrum of R6G (acceptor) has very good overlap with the RO−emission and poor overlap with ROH emission. It is observed that FRET occurs readily from the RO−* state of HPTS (donor) to R6G (acceptor). Multiple timescales of FRET were detected from the rise time of acceptor emission. The different timescales correspond to different donor–acceptor distances. The ultrafast components (8.5 and 13 ps) are assigned to FRET at a close contact of donor and acceptor (≈20 Å). The longer components (500 and 800 ps) arise from long‐distance FRET from the donor to the acceptor (≈40 Å) located in different regions of the CTAC micelle. The larger donor–acceptor distances agree with those obtained from an sm‐FRET study. On addition of 4 MNaCl to CTAC, the rate of proton transfer (kPT) slowed by about eight and two times, respectively, for the fast and slow sites of the CTAC micelle. As a result, the intensity of the ROH emission increases and that of RO−decreases. The decrease in the intensity of the RO−emission causes a decrease in the efficiency of FRET.
ortho‐Phenylenediamine: An Effective Spacer to Build Highly Magnetic Fe3O4/Au Nanocomposites
Authors: Zhao Xinmei , Hosmane Narayan S. , Wu Aiguo 
Published: November 2012

Abstract1,2‐Diaminobenzene, popularly known as ortho‐phenylenediamine (PDA), is found to be a prototype spacer for the deposition of gold nanoparticles on the surfaces of Fe3O4 microspheres. Upon carbonization with PDA, the morphology of the product changes significantly, and the resulting nanocomposites exhibit enhanced magnetism beyond the saturation value of Fe3O4. The Fe3O4/Au nanocomposites show good surface‐enhanced Raman spectroscopy activity with a detection limit of 10−15 M.
Metal‐Supported Aluminosilicate Ultrathin Films as a Versatile Tool for Studying the Surface Chemistry of Zeolites
Authors: Shaikhutdinov Shamil , Freund Hans‐Joachim 
Published: November 2012

AbstractThe application of a variety of “surface‐science” techniques to elucidate surface structures and mechanisms of chemical reactions at zeolite surfaces has long been considered as almost impossible because of the poor electrical and thermal conductivity of those materials. Here, we show that the growth of a thin aluminosilicate film on a metal single crystal under controlled conditions results in adequate and well‐defined model systems for zeolite surfaces. In principle, silicate films that contain metals other than Al (e.g. Ti, Fe, etc) may be prepared in a similar way. We believe that this approach opens up a new playground for experimental and theoretical modeling of zeolites, aimed at a fundamental understanding of structure–reactivity relationships in such materials.
Deposition of Au Thin Films and Nanoparticles by MOCVD
Authors: Parkhomenko Roman G. , Morozova Natalia B. , Zharkova Galina I. , Shubin Yuri V. , Trubin Sergey V. , Kriventsov Vladimir V. , Kuchumov Boris M. , Koretskaya Tatiana P. , Igumenov Igor K. 
Published: November 2012

AbstractUsing metal‐organic (MO)CVD, gold films and arrays of gold nanoparticles are obtained from volatile organometallic dimethylgold(III) complexes with O, N, S donor ligands. As precursors, such compounds as (CH3)2Au(OAc), (CH3)2Au(piv), (CH3)2Au(OQ), (CH3)2Au(SQ), (CH3)2Au(thd), and (CH3)2Au(dtc) were used. Deposition processes are carried out within a low pressure (LP)CVD reactor with additional vacuum ultraviolet (VUV) stimulation, with and without a hydrogen reactant gas. The influence of precursor structure on the morphology of the deposited layers is demonstrated. The use of precursor (CH3)2Au(OQ) results in obtaining ultra‐thin continuous gold film ∼3 nm thick. It is established that with hydrogen reactant gas injected into the system, the amount of impurities in the film decreases. With the VUV stimulation, the gold content in the films amounts to almost 100%; in addition, the morphology of coatings is observed to change significantly. According to the X‐ray diffraction (XRD) phase analysis, gold crystallites in the films grow mainly in the [111] direction.
A Study on Sc2O3‐Stabilized Zirconia Obtained by MOCVD as a Potential Electrolyte for Solid Oxide Fuel Cells
Authors: El Habra Naida , Sartori Andrea , Bolzan Marco , Favaro Monica , Casarin Maurizio , Boldrini Stefano , Doubova Lioudmila , Rossetto Gilberto 
Published: November 2012

AbstractDense, crack‐free thin films (<5 µm) of the nanostructured scandia‐zirconia system (Sc2O3:ZrO2) stabilized in the cubic‐fluorite phase (c‐ZrO2) are deposited through conventional low‐pressure metal‐organic(LP‐MO) CVD by using β‐diketonate metal complexes as precursors [(Zr(tmhd)4 and Sc(tmhd)3, with –tmhd = 2,2,6,6‐tetramethyl‐3,5‐heptanedionate]. The compositional (energy dispersive X‐ray spectroscopy – EDX), structural (X‐ray diffraction – XRD) and morphological (field emission gun–environmental scanning electron microscopy – FEG‐ESEM) analyses, confirmed the growth of dense partially and fully stabilized ZrO2, a suitable electrolyte for solid oxide fuel cells (SOFC). Results of impedance spectroscopy, which investigates the electrical conductivity of coating, deposited as thin as possible to guarantee the uniform covering of a porous substrate, are reported. Results of thin films of yttria‐zirconia system (Y2O3:ZrO2), deposited with the same method, are also reported for comparison.
HIKES: Hierarchical key establishment scheme for wireless sensor networks
Authors: Ibriq J. , Mahgoub I. 
Published: November 2012

SUMMARYThis paper presents a hierarchical key establishment scheme called HIKES. The base station in this scheme, acting as the central trust authority, empowers randomly selected sensors to act as local trust authorities authenticating, on its behalf, the cluster members and issuing private keys. HIKES uses a partial key escrow scheme that enables any sensor node selected as a cluster head to generate all the cryptographic keys needed to authenticate other sensors within its cluster. This scheme localizes secret key issuance and reduces the communication cost with the base station. HIKES provides an efficient broadcast authentication in which source authentication is achieved in a single transmission and a good defense for the routing mechanism. HIKES defends the routing mechanism against most known attacks and is robust against node compromise. HIKES also provides high addressing flexibility and network connectivity to all sensors in the network, allowing sensor addition and deletion. Simulation results have shown that HIKES provides an energy‐efficient and scalable solution to the key management problem. Copyright © 2012 John Wiley & Sons, Ltd.