bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved method for dispersing clay in a monomer or bis(2‐hydroxyl ethyl terephthalate) before in situ polymerization of poly(ethylene terephthalate)/montmorillonite nanocomposites
Authors: Labde Rohan , Lofgren Elizabeth A. , Jabarin Saleh A.
Published: January 2012

Natural montmorillonite (MMT) clay nanomaterials were successfully dispersed in poly(ethylene terephthalate) (PET) through two new and enhanced in situ polymerization methods. In the case of PET/MMT nanocomposites prepared through the esterification (ES) reaction clay‐addition method, unmodified MMT clays were dispersed in water and, then, the ethylene glycol monomer of PET before the preparation of bis(2‐hydroxyl ethyl) terephthalate (BHET) nanocomposites, which later underwent in situ polymerization. For nanocomposites prepared through the polycondensation (PC) reactor method, selected amounts of clay were dispersed in ethanol, with stirring inside the reactor. A portion of crushed BHET was then added to the PC reactor, and the combined mixture was stirred to achieve dispersion. The remaining BHET was added and mixed, the ethanol was evaporated by heating, and in situ polymerization was initiated. Morphological analysis by X‐ray diffraction and transmission electron microscopy confirmed the presence of exfoliated and intercalated clay structures in the nanocomposites prepared through both ES and PC clay‐addition methods. Nanocomposites containing lower concentrations of clay showed increases in the oxygen barrier properties in comparison to values obtained for the unmodified PET. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mechanical properties of polypropylene blended with esterified and alkylated lignin
Authors: Maldhure Atul V. , Ekhe J. D. , Deenadayalan E.
Published: January 2012

Lignin does not show miscibility with commercial polyolefins. Therefore, industrial waste lignin was modified in two different ways and subsequently blended with commercial polypropylene (PP) up to 25 wt %. A Brabender electronic plasticorder was used for melt mixing at 190°C. The influence of different modifications on the mechanical properties and processing stability was studied for both polymer blends. The blends of PP and lignin modified (esterified) with maleic anhydride showed less deterioration in the mechanical properties compared to blends of PP and alkylated lignin with dichloroethane. Intermolecular interactions between the PP matrix and modified lignin were concluded on the basis of indicative values derived from various relevant theoretical models to the experimental data. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synergistic effect of phosphorus‐containing nanosponges on intumescent flame‐retardant polypropylene
Authors: Lai Xuejun , Zeng Xingrong , Li Hongqiang , Yin Changyu , Zhang Haili , Liao Feng
Published: January 2012

A novel nanosponge (NS) was synthesized via the crosslinking of β‐cyclodextrin with epoxy resin. Subsequently, a phosphorus‐containing nanosponge (P–NS) was prepared by the absorbance of resorcinol bis(diphenyl phosphate) into the NS, and it was used as a synergistic agent of intumescent flame retardance in a polypropylene (PP)/melamine pyrophosphate/pentaerythritol composite. The synergistic effect between P–NS and the intumescent flame retardant (IFR) was investigated by thermogravimetry, limiting oxygen index (LOI) testing, vertical burning (UL‐94) testing, cone calorimeter testing, and scanning electron microscopy (SEM). The results show that P–NS significantly improved the flame retardancy of the PP/IFR composite. When 3.0 wt % P–NS replaced the same amount of IFR in the composite, the LOI value increased from 29.0 to 32.5%, the UL‐94 rating was enhanced from V‐1 to V‐0, and the peak heat release rate decreased substantially from 343 to 235 kW/m2. Simultaneously, the total heat release and mass loss rate decreased dramatically. Furthermore, the SEM results show that the quality of char formation of the PP/IFR/P–NS was superior to that of the PP/IFR composite. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Maleic anhydride based copolymer dispersions for surface modification of polar substrates
Authors: Gunbas I. D. , Wouters M. E. L. , Hendrix M. M. R. M. , van Benthem R. A. T. M. , Koning C. E. , Noordover B. A. J.
Published: January 2012

In this article, we report the modification of poly(styrene‐alt‐maleic anhydride) (PSMA) with monofunctional amine‐terminated poly(dimethyl siloxane) (PDMS–NH2) by thermal imidization, followed by the preparation and characterization of a surfactant‐free artificial latex thereof and application of this latex onto cotton fabric. The imidization reaction was monitored by NMR and attenuated total reflection Fourier transform infrared (ATR–FTIR) spectroscopy. 1,2‐Cyclohexyldicarboxylic anhydride was chosen as a model compound for the PSMA copolymer; this allowed a more detailed characterization by NMR and ATR–FTIR spectroscopy. After the PSMA/PDMS–NH2 imidization reached completion, a fraction of the anhydrides were ammonolyzed. In this way, a self‐emulsifying latex with an average particle diameter of approximately 145 nm and a ζ potential of −56 mV was obtained. It was found that the PDMS‐modified PSMA latex in which 30 mol% of the initial amount of anhydride groups were previously imidized by using PDMS‐NH2 and a fraction of the anhydrides were ammonolyzed with 0.3 eq. of NH3 (PSMA30) was stable in the pH range 4–10. The water contact angle values of the latex‐coated cotton textile fabric indicated a hydrophobized surface, with a static contact angle of 135.7°± 1.2°. The washing studies with a standard soap solution of the cotton samples with or without crosslinker showed that the crosslinked PSMA30 offered a good coating durability to the cotton. This waterborne resin based on surfactant‐free latices displayed promising properties for coating applications and seemed to be very suitable for the hydrophobization of polar surfaces. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Catalytic performance and nanoclay effects on post‐solid‐state polyamidation: The case of polyamide 6,6 nanocomposites
Authors: Boussia A. C. , Konstantakopoulou M. O. , Vouyiouka S. N. , Papaspyrides C. D.
Published: January 2012

The catalytic performance of common additives was explored during the solid‐state postpolymerization (SSP) of polyamide 6,6 prepolymers. In particular, the influence of a phosphorous‐containing antioxidant and its combination with a nanofiller (clay) was examined during the SSP reaction at 200°C for times up to 4 h. The antioxidant, at a concentration of 1 phr, was found to strongly accelerate the SSP process by more than quintupling (435%) the reaction rate. The antioxidant–clay system (1 phr each) also catalyzed the SSP process and resulted in a near tripling (197%) of the reaction rate; this implied, however, a reduced single antioxidant catalytic performance. The latter was attributed to counteractions involving the diffusivity of polycondensation water versus clay hydrophilicity and to physical adsorption phenomena between the antioxidant and the clay. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Enhanced swelling properties of a novel sodium alginate‐based superabsorbent composites: NaAlg‐g‐poly(NaA‐co‐St)/APT
Authors: Shi Xiaoning , Wang Wenbo , Kang Yuru , Wang Aiqin
Published: January 2012

A novel alginate‐based superabsorbent composite with enhanced swelling properties was synthesized by simultaneously grafted copolymerization partially neutralized acrylic acid (NaA), styrene (St) onto the sodium alginate (NaAlg) backbones in the presence of attapulgite (APT). The structure and morphology of the synthesized superabsorbent composites were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet‐visible (UV‐vis) spectra and Field emission scanning electron microscope (FESEM). Major factors affecting the swelling ratio according to Flory's theory were discussed. The superabsorbent composite synthesized under optimum reaction conditions exhibits the maximum swelling ratio of 587 g/g in distilled water and 73 g/g in 0.9 wt % NaCl solution. Compared with NaAlg‐g‐PNaA hydrogel, the simultaneous introduction of tiny amount of St and APT not only enhanced the swelling ratio but also increased the initial swelling rate. In addition, the effects of salt and pH medium on the swelling behaviors were investigated, and the results indicated that the composite showed smart swelling behavior in multivalent salt solution and better pH‐responsitivity in the pH 2.2 and 7.4 solutions, which makes it promising for drug delivery application. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis, spectroscopy, and electrochemical investigation of new conjugated polymers containing thiophene and 1,3,4‐thiadiazole in the main chain
Authors: Patil Prashant S. , Haram Nanda S. , Pal Ravindra R. , Periasamy N. , Wadgaonkar Prakash P. , Salunkhe Manikrao M.
Published: January 2012

Novel photoluminescent donor–acceptor poly(p‐phenylenevinylene)‐type conjugated polymers containing thiophene and 1,3,4‐thiadiazole units in the main chain were synthesized from 2,5‐bis(5‐bromomethyl‐2‐thienyl)‐1,3,4‐thiadiazole and 1,3/1,4‐benzenedialdehyde by Wittig–Horner reaction. The synthesized polymers were characterized by the use of thermal analysis and spectroscopic (infrared, UV‐visible absorption, and photoluminescence) measurement. The resultant material exhibited bluish green, green, and orange fluorescence in their solution and thin film and solid forms, respectively. The redox property of the polymers has also been studied by cyclic voltammetry. The optical and electrochemical studies reveal that these novel polymers are new promising materials for the development of efficient polymer light‐emitting diodes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Structure‐related behavior of hybrid organic–inorganic materials prepared in different synthesis conditions from Zr‐based NBBs and 3‐methacryloxypropyl trimethoxysilane
Authors: Di Maggio R. , Callone E. , Girardi F. , Dirè S.
Published: January 2012

The copolymerization of zirconium oxo‐clusters (Zr12) with 3‐methacryloxypropyl (trimethoxy)silane (MPTMS), using a Si/Zr molar ratio of 4, was investigated. The hybrid samples were prepared both with and without organosilane prehydrolysis. Differential scanning calorimetry (DSC), multinuclear liquid, and solid state NMR analyses and Fourier transform infrared (FTIR) spectroscopy were used to characterize the hybrid materials and study the influence of synthesis conditions on condensation and polymerization. The degree of condensation (DOC) of the silsesquioxane network and the polymerization yield are generally high. However, the organosilane prehydrolysis step leads to the reduction of the extent of phase interaction, thus favoring the phase separation between silica‐zirconia‐based domains. Dynamic mechanical spectroscopy (DMS) analyses were performed on the hybrid polymers obtained by means of the two synthetic pathways. The sample prepared without the organosilane prehydrolysis step presents a higher glass transition temperature (Tg) than the one with silane prehydrolysis. By heating above the Tg, the samples retain shape and size, due to the lack of viscous flow. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
New stabilizers for polystyrene based on 2‐thioacetic acid benzothiazol complexes
Authors: Yousif Emad , Salimon Jumat , Salih Nadia
Published: January 2012

The photostabilization of polystyrene (PS) films by 2‐thioacetic acid benzothiazol with Sn(II), Cd(II), Ni(II), Zn(II), and Cu(II) complexes was investigated. The PS films containing complexes of concentration 0.5% by weight were produced by the casting method from chloroform solvent. The photostabilization activities of these compounds were determined by monitoring the carbonyl and hydroxyl indices with irradiation time. The changes in viscosimetric average molecular weight of PS with irradiation time were also tracked (using benzene as a solvent). The quantum yield of the chain scission (ϕcs) of these complexes in PS films was evaluated and found to range between 3.60 × 10−6 and 7.78 × 10−6. The results obtained showed that the rate of photostabilization of PS in the presence of the additive is in the following trend: Ni(L)2 > Cu(L)2 > Zn(L)2 > Cd(L)2 > Sn(L)2. According to the experimental results obtained, several mechanisms were suggested depending on the structure of the additive. Among UV absorption, peroxide decomposer and radical scavenger for photostabilizer additive mechanisms were suggested. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Electrospinning of cellulose nanofibers from ionic liquids: The effect of different cosolvents
Authors: Härdelin Linda , Thunberg Johannes , Perzon Erik , Westman Gunnar , Walkenström Pernilla , Gatenholm Paul
Published: January 2012

Cellulose was electrospun with various concentrations of ionic liquid and cosolvent. Three different cosolvents were used in this study; dimethylacetamide (DMAc), dimethyl formamide (DMF), and dimethyl sulfoxide (DMSO). The cosolvents were added to modify the viscosity, electrical conductivity, and surface tension of the solutions. The solubility of cellulose in ionic liquids is highly affected by changes in solvent properties on the molecular level in the binary solvent systems. The difference in molecular structure of the cosolvents and the interactions between cosolvent and ionic liquid can explain the difference in dissolution power of the cosolvents. Scanning electron microscope (SEM) was used to characterize electrospun cellulose fibers. For the systems tested the importance of having a rather high viscosity and high surface tension, and some degree of shear thinning to produce fibers is shown. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of organic ligands with conjugated π‐bonds on the structure of iodine–α‐dextrin complexes
Authors: Yuldasheva Gulnara A. , Zhidomirov Georgii M. , Ilin Aleksandr I.
Published: January 2012

Using X‐ray data for iodine–α‐dextrin complexes and the results of quantum chemical ab initio restricted Hartree–Fock/3‐21G** level calculations, a model of drug active complex (AC) Armenicum with anti‐HIV action was proposed. It was suggested that the drug AC contains molecular iodine allocated inside of α‐dextrin helix and coordinated by lithium halogenides and a protein component of lymphocyte ribosomes. The electronic structure of I2 in this complex differs from its characteristics in complexes with organic ligands or the free I2. In the considered ACs, the molecular iodine displays acceptor (donor) properties toward the α‐dextrins (lithium halogenides). A mechanism of Armenicum anti‐HIV action is suggested. Under the influence of molecular iodine‐containing drug AC, the structure of HIV DNA is modified—it becomes more π‐donor‐active against proteins and peptide nucleotides of viral DNA form a stable complex with molecular iodine and lithium halogenides.
Scientific discovery as a combinatorial optimisation problem: How best to navigate the landscape of possible experiments?
Authors: Kell Douglas B.
Published: January 2012

A considerable number of areas of bioscience, including gene and drug discovery, metabolic engineering for the biotechnological improvement of organisms, and the processes of natural and directed evolution, are best viewed in terms of a ‘landscape’ representing a large search space of possible solutions or experiments populated by a considerably smaller number of actual solutions that then emerge. This is what makes these problems ‘hard’, but as such these are to be seen as combinatorial optimisation problems that are best attacked by heuristic methods known from that field. Such landscapes, which may also represent or include multiple objectives, are effectively modelled in silico, with modern active learning algorithms such as those based on Darwinian evolution providing guidance, using existing knowledge, as to what is the ‘best’ experiment to do next. An awareness, and the application, of these methods can thereby enhance the scientific discovery process considerably. This analysis fits comfortably with an emerging epistemology that sees scientific reasoning, the search for solutions, and scientific discovery as Bayesian processes.
Effects of 6 months of endurance training on neutrophil functions to produce reactive oxygen species and mental states in male long‐distance runners
Authors: Kumae Takashi , Suzukawa Kazuhiro , Ishii Takashi
Published: January 2012

To clarify changes of neutrophil functions, mental conditions and relationships among them, 19 male elite long‐distance runners participated in this study for 6 months. Examinations, with informed consent, were carried out once a month. According to the results of physical characteristics, it was thought that training intensity was reduced after the main race, Hakone‐Ekiden. Neutrophil functions were estimated by indices of reactive oxygen species production, determined by luminol‐ and lucigenin‐dependent chemiluminescence (LmCL and LgCL, respectively) and cytochrome c reduction methods. The peak times (PT) in LmCL and LgCL (LgPT) were most prolonged in January and December, respectively. The peak heights (PH) in LmCL (LmPH) were enhanced in February. Decreased levels of negative categories in the profile of mood state (POMS) questionnaire and the total mood state (TMS) of POMS were observed in February without significance. Correlation analysis using measured values revealed significant negative correlation between LmPH and negative categories in POMS; however, these correlations were possibly a mere appearance, caused by personal differences. After eliminating personal differences, LgPT correlated positively to depression (p < 0.05), anger (p < 0.05), fatigue (p < 0.01) and TMS (p < 0.05). These results suggest that the mean time from the recognition of foreign matter to the maximum production of superoxide from neutrophils is prolonged in the mentally suppressed conditions found under continuous physical training. Copyright © 2012 John Wiley & Sons, Ltd.
Plant bioreactors – the taste of sweet success
Authors: Stoger Eva
Published: January 2012

See accompanying article by Pham et al. DOI: 10.1002/biot.201100430
Quantitation of unbound sunitinib and its metabolite N‐desethyl sunitinib (SU12662) in human plasma by equilibrium dialysis and liquid chromatography–tandem mass spectrometry: application to a pharmacokinetic study
Authors: Rais Rana , Zhao Ming , He Ping , Xu Linping , Deeken John F. , Rudek Michelle A.
Published: January 2012

A rapid, selective, and sensitive liquid chromatography–tandem mass spectrometry method was developed and validated for the simultaneous determination of unbound sunitinib and its active metabolite N‐desethyl sunitinib in plasma. Plasma and post‐dialysis buffer samples were extracted using a liquid–liquid extraction procedure with acetonitrile–n‐butylchloride (1:4, v/v). Chromatographic separation was achieved on a Waters X‐Terra® MS RP18 column with a mobile phase consisting of acetonitrile and water (60:40, v/v) containing formic acid (0.1%, v/v) using an isocratic run, at a flow‐rate of 0.2 mL/min. Analytes were detected by electrospray tandem mass spectrometry in the selective reaction monitoring mode. Linear calibration curves were generated over the ranges 0.1–100 and 0.02–5 ng/mL for sunitinib and 0.2–200 and 0.04–10 ng/mL for N‐desethyl sunitinib in plasma and in phosphate‐buffered solution, respectively. The values for both within‐day and between‐day precision and accuracy were well within the generally accepted criteria for analytical methods. The analytical range was sufficient to determine the unbound and total concentrations of both analytes. The method was applied for measurement unbound concentrations in addition to total concentrations of sunitinib and its metabolite in plasma of a cancer patient receiving 50 mg daily dose. Copyright © 2012 John Wiley & Sons, Ltd.
Gene networking and inflammatory pathway analysis in a JMJD3 knockdown human monocytic cell line
Authors: Das Nando Dulal , Jung Kyoung Hwa , Choi Mi Ran , Yoon Hyun Soo , Kim Seung Hyun , Chai Young Gyu
Published: January 2012

JMJD3, a Jumonji C family histone demethylase, is induced by transcription factor, nuclear factor‐kappa B (NF‐κB), in response to various stimuli. JMJD3 is crucial for erasing histone‐3 lysine‐27 trimethylation (H3K27me3), a modification associated with transcriptional repression and is responsible for the activation of a diverse set of genes. Here, we identify the genes in human leukaemia monocyte (THP‐1) human monocytic cells that are significantly affected by the stable knockdown (kd) of JMJD3. Global gene expression levels were detected in stable JMJD3 knockdown THP‐1 cells and in tumor necrosis factor‐alpha (TNF‐α)‐stimulated JMJD3‐kd THP‐1 cells by using a 12‐plex NimbleGen human whole genome array. In addition, datasets were analysed by using Ingenuity Pathway Analysis. Stable knockdown of JMJD3 in THP‐1 cells affected particularly in expression levels and in downstream effects on inflammatory signalling pathways. JMJD3 attenuation down‐regulates various key genes in NF‐κB, chemokine and CD40 signalling, and mostly affects inflammatory disease response molecules. In addition, chromatin immunoprecipitation revealed that JMJD3‐kd could inhibit several NF‐κB‐regulated inflammatory genes by recruiting repressive histone‐3 lysine‐27 trimethylation to their promoters. Moreover, this study significantly highlights the connexion of NF‐κB with JMJD3, which suggests an epigenetic regulation in different signalling pathways. Finally, this study establishes novel JMJD3 targets through Ingenuity Pathway Analysis. Copyright © 2012 John Wiley & Sons, Ltd.
Pressure and Electrical Resistivity Measurements on Hot Expanded Metals: Comparisons with Quantum Molecular Dynamics Simulations and Average‐Atom Approaches
Authors: Clérouin J. , Starrett C. , Noiret P. , Renaudin P. , Blancard C. , Faussurier G.
Published: January 2012

We present experimental results on pressures and resistivities of expanded nickel and titanium at respective densities of 0.1 g/cm3 and 0.2 g/cm3, and in a range of temperature of 1‐3 eV that corresponds to the warm dense matter (WDM) regime. These data are used to benchmark different theoretical approaches. A comparison is presented between fully 3‐dimensional quantum molecular dynamics (QMD) methods, based on density functional theory, with average‐atom (AA) methods, that are essentially one dimensional. AA methods are used to identify interband transitions and photoionization thresholds. In this regime the evaluation of the thermodynamic properties as well as electrical properties is difficult due to the concurrence of density and thermal effects which directly drive the metal‐non‐metal transition. QMD simulations are also helpful to give a precise estimation of the temperature of experiments which is not directly accessible [1] (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Long‐Range Correlations of the Surface Charge Density Between Electrical Media with Flat and Spherical Interfaces
Authors: Šamaj L.
Published: January 2012

We study the asymptotic long‐range behavior of the time‐dependent correlation function of the surface charge density induced on the interface between two media of distinct dielectric functions which are in thermal equilibrium with one another as well as with the radiated electromagnetic field. We start with a short review which summarizes the results obtained by using quantum and classical descriptions of media, in both non‐retarded and retarded regimes of particle interactions. The classical static result for the flat interface is rederived by using a combination of the microscopic linear response theory and the macroscopic method of electrostatic image charges. The method is then applied to the case of a spherically shaped interface between media (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge Correlations in a Harmonic Trap
Authors: Wrighton J. , Kählert H. , Ott T. , Ludwig P. , Thomsen H. , Dufty J. , Bonitz M.
Published: January 2012

A system of N classical Coulomb charges trapped in a harmonic potential displays shell structure and orientational ordering. The local density profile is well understood from theory, simulation, and experiment. Here, pair correlations are considered for this highly inhomogeneous system for both the fluid and ordered states. In the former, it is noted that there is a close relationship to pair correlations in the uniform one component plasma. For the ordered state, it is shown that the disordered “tiling” is closely related to the ground state Thomson sites for a single sphere (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Classical Representation of a Quantum System at Equilibrium
Authors: Dufty J. W. , Dutta S.
Published: January 2012

A quantum system at equilibrium is represented by a corresponding classical system, chosen to reproduce the thermodynamic and structural properties. The objective is to develop a means for exploiting strong coupling classical methods (e.g., MD, integral equations, DFT) to describe quantum systems. The classical system has an effective temperature, local chemical potential, and pair interaction that are defined by requiring equivalence of the grand potential and its functional derivatives with respect to the external and pair potentials for the classical and quantum systems. Practical inversion of this mapping for the classical properties is effected via the hypernetted chain approximation, leading to representations as functionals of the quantum pair correlation function. As an illustration, the parameters of the classical system are determined approximately such that ideal gas and weak coupling RPA limits are preserved (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conduction of Strongly Coupled Electrons Through Narrow Channels on Liquid Helium Surface: Simulation
Authors: Totsuji H.
Published: January 2012

The conduction of electrons through narrow channels formed on the surface of liquid helium is analyzed by numerical simulations. It is shown that, when electrons are strongly coupled, we have nonlinear and even negative dependence of conductance on the width of the constriction which is controlled by the gate voltage (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamic Structure Factor for a Harmonic Oscillator and the Harmonic Oscillator Chain
Authors: Wierling A. , Sawada I.
Published: January 2012

The recurrance relation method is employed to determine the dynamic structure factor for the single harmonic oscillator and a linear chain of harmonic oscillators. Approximative schemes based on this approach are proposed. Comparison is made with exactly known results (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Equation of State of Al Based on the Thomas–Fermi Model
Authors: Shemyakin O.P. , Levashov P.R. , Khishchenko K.V.
Published: January 2012

A wide‐range semiempirical equation of state for aluminum applicable both at near‐normal conditions and in dense plasma is presented. The finite‐temperature Thomas–Fermi model is used for the thermal contribution of electrons thus diminishing the number of fitting parameters and giving information about a mean ion charge. The constructed equation of state agrees with majority of available shock‐wave data (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Instabilities in Yukawa Liquids
Authors: Rosenberg M. , Kalman G. J. , Hartmann P.
Published: January 2012

A strongly coupled Yukawa liquid is a system of charged particles which interact via a screened Coulomb interaction and in which the electrostatic energy between neighboring particles is larger than their thermal energy but not large enough for crystallization. Various plasma systems including ultracold neutral plasmas and complex (dusty) plasmas can exist in this strongly coupled liquid phase.Here we investigate instabilities driven by the relative streaming of plasma components in three‐dimensional Yukawa liquids with a focus on complex plasmas. This includes a dust acoustic instability driven by weakly coupled ions streaming through the dust liquid, and a dust‐dust instability driven by the counter‐streaming of strongly coupled dust grains. Compared to the Vlasov behavior we find there can be a substantial modification of the unstable wavenumber spectrum due to strong coupling effects (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of small RNAs in Xenopus tropicalis gastrulae
Authors: Faunes Fernando , Almonacid Leonardo I. , Melo Francisco , Larrain Juan
Published: January 2012

Here, we report and characterize deep sequencing data and bioinformatics analysis of small RNAs from Xenopus tropicalis gastrula. A total of 17,553,124 reads with perfect match to the genome derived from 2,616,053 unique sequences were identified. Seventy‐seven percent of theses sequences were not found in previous reports from X. tropicalis oocytes and somatic tissues. Bioinformatics analyses indicate that a large fraction of the small RNAs are PIWI‐interacting RNAs. Up to 23.9% of small RNAs mapped to transposable elements and 27% to genic regions. Most of abundant transposable derived small RNAs are found in oocyte and gastrula libraries, suggesting that transposon needs to be silenced also during early development. Additionally, miRNAs were identified and many of them are not present in oocytes, suggesting that miRNA expression is stage specific. To the best of our knowledge, this is the first high throughput data release and bioinformatics characterization of small RNAs during Xenopus development. genesis 50:260–270, 2012. © 2012 Wiley Periodicals, Inc.
Development of xenopus resource centers: The national xenopus resource and the european xenopus resource center
Authors: Pearl Esther J. , Grainger Robert M. , Guille Matthew , Horb Marko E.
Published: January 2012

Xenopus is an essential vertebrate model system for biomedical research that has contributed to important discoveries in many disciplines, including cell biology, molecular biology, physiology, developmental biology, and neurobiology. However, unlike other model systems no central repository/stock center for Xenopus had been established until recently. Similar to mouse, zebrafish, and fly communities, which have established stock centers, Xenopus researchers need to maintain and distribute rapidly growing numbers of inbred, mutant, and transgenic frog strains, along with DNA and protein resources, and individual laboratories struggle to accomplish this efficiently. In the last 5 years, two resource centers were founded to address this need: the European Xenopus Resource Center (EXRC) at the University of Portsmouth in England, and the National Xenopus Resource (NXR) at the Marine Biological Laboratory in Woods Hole, MA. These two centers work together to provide resources and support to the Xenopus research community. The EXRC and NXR serve as stock centers and acquire, produce, maintain and distribute mutant, inbred and transgenic Xenopus laevis and Xenopustropicalis lines. Independently, the EXRC is a repository for Xenopus cDNAs, fosmids, and antibodies; it also provides oocytes and wild‐typefrogs within the United Kingdom. The NXR will complement these services by providing research training and promoting intellectual interchange through hosting minicourses and workshops and offering space for researchers to perform short‐term projects at the Marine Biological Laboratory. Together the EXRC and NXR will enable researchers to improve productivity by providing resources and expertise to all levels, from graduate students to experienced PIs. These two centers will also enable investigators that use other animal systems to take advantage of Xenopus' unique experimental features to complement their studies. genesis 50:155–163, 2012. © 2012 Wiley Periodicals, Inc.
Lactide Polymerisation with Complexes of Neutral N‐Donors – New Strategies for Robust Catalysts
Authors: dos Santos Vieira Ines , Herres‐Pawlis Sonja
Published: January 2012

Ring‐opening polymerisation of cyclic esters represents a growing field of research, because the resulting polymers are biodegradable and mostly based on renewable raw materials, which ensures increasing interest in this process within the context of green chemistry. Up to now, neutral N‐donor ligands have been overlooked in their potential to stabilise catalytically active systems. This contribution summarises recent developments in this area as well as their applicability in lactide polymerisation with special regard to the reaction conditions. When a use on the industrial scale is targeted, tolerance towards moisture, air, lactide impurities and high temperatures is an important issue to be considered during catalyst design. A multitude of sodium, calcium and zinc complexes with amines, carbenes, guanidines, phosphinimines, pyridines and tris(pyrazolyl)methanes is discussed and their activity in lactide polymerisation is highlighted.
Assignment of Absolute Configuration of Bis‐γ‐pyrone Polypropionates from Marine Pulmonate Molluscs
Authors: Wang Jian‐Rong , Carbone Marianna , Gavagnin Margherita , Mándi Attila , Antus Sándor , Yao Li‐Gong , Cimino Guido , Kurtán Tibor , Guo Yue‐Wei
Published: January 2012

The absolute configurations of onchidione (1), previously reported from the marine pulmonate Onchidium sp., and the related alcohols onchidiol (2) and 4‐epi‐onchidiol (3), first described as methanolysis products of 1, were assigned by X‐ray diffraction analysis and solid‐state time‐dependent density functional theory electronic circular dichroism. Alcohol 3 was incorrectly reported as the C‐16 epimer of 2.
Practical Synthesis of Unsymmetrical Diarylacetylenes from Propiolic Acid and Two Different Aryl Bromides
Authors: Tartaggia Stefano , De Lucchi Ottorino , Gooßen Lukas J.
Published: January 2012

A palladium catalyst that mediates the one‐pot sequential Sonogashira and decarboxylative coupling of propiolic acid with two different aryl bromides has been developed. Selective coupling of the first aryl bromide was achieved in the presence of a copper‐free, monometallic catalyst generated in situ from allylpalladium chloride dimer and SPhos with tetra‐n‐butylammonium fluoride as the base in an N‐methyl‐2‐pyrrolidone/water solvent mixture. Upon addition of another aryl bromide and raising the temperature from 50 to 80 °C, the intermediate arylpropiolic acid underwent decarboxylative coupling to give the corresponding diarylacetylene. Thus, the new system permits a one‐pot three‐component synthesis of unsymmetrical diarylacetylenes from widely available aryl bromides, rather than expensive aryl iodides, and propiolic acid, rather than (trimethylsilyl)acetylene, as an inexpensive and easy‐to‐handle acetylene synthon. The process is highly selective, modular, and gives access to a wide range of unsymmetrical diarylacetylenes in good yields.
Role of cell cycle‐associated proteins in microglial proliferation in the axotomized rat facial nucleus
Authors: Yamamoto Shinichi , Kohsaka Shinichi , Nakajima Kazuyuki
Published: January 2012

We analyzed cell cycle‐associated proteins, including cyclins, cyclin‐dependent protein kinases (Cdks), and Cdk inhibitors (CdkIs) in the axotomized rat facial nucleus. Immunoblotting revealed that cyclin A and cyclin D are induced 3–5 days after transection. The induced cyclin A was immunohistochemically recognized in microglia. Cdk2 and Cdk4 were also detected in the facial nucleus. The CdkI p21 was elevated 5 days after axotomy. Inhibition experiments in vitro using a cFms (receptor for macrophage‐colony stimulating factor, M‐CSF) inhibitor indicated that M‐CSF‐cFms signaling leads to upregulation of the levels of cyclin A, cyclin D, proliferating cell nuclear antigen (PCNA), and cFms in microglia. The role of cyclin A/Cdk2 activity in M‐CSF‐dependent microglial proliferation was ascertained using the specific inhibitor purvalanol A. Experiments using specific mitogen‐activated protein kinase inhibitors suggested that c‐Jun N‐terminal kinase (JNK) is associated with M‐CSF‐dependent induction of cyclins and PCNA, whereas p38 is associated with cFms induction. Both JNK and p38 were proved to be phosphorylated by stimulation with M‐CSF. Our results indicated that cyclin A, cyclin D, Cdk2, Cdk4, and p21 are involved in microglial proliferation in the transected facial nucleus, and that the M‐CSF‐dependent upregulations of cyclins/PCNA and cFms in microglia are differentially regulated by JNK and p38. © 2012 Wiley Periodicals, Inc.
Double‐blind controlled trial of venlafaxine for treatment of adults with attention deficit/hyperactivity disorder
Authors: Amiri Shahrokh , Farhang Sara , Ghoreishizadeh Mohammad Ali , Malek Ayyoub , Mohammadzadeh Soleiman
Published: January 2012

Background

Attention deficit/hyperactivity disorder (ADHD) is one of the most common mental disorders beginning in childhood that may continue to adulthood. The purpose of this study was to evaluate the possible therapeutic effect of venlafaxine in adults with ADHD.

Methods

In a double‐blind setting, drug‐naïve adults with a diagnosis of ADHD based on DSM‐IV‐TR criteria were randomly selected to receive either venlafaxine (up to 225 mg/day) or a placebo for 6 weeks. The Conners Adult ADHD Rating Scale self‐report screening version was administered before and during the treatment at 2‐week intervals to measure the therapeutic effects.

Results

The mean age (SD) of patients was 30.5 (8.1) years. Eleven out of 20 patients receiving venlafaxine and 13 out of 21 patients receiving the placebo were male. The two groups were not significantly different in terms of age, educational level, weight, or blood pressure.

Significant decrease was observed in both subscales (inattentive, hyperactive/impulsive), total ADHD symptoms score, and ADHD index in both the venlafaxine and the placebo groups. Seventy‐five percent of treatment group versus 20% of placebo group met treatment response criteria when defined as a 25% drop in total ADHD score (p = 0.001).

No serious adverse effects were reported during the trial.

Conclusions

In this double‐blind trial, the symptoms of adult ADHD decreased after a 6‐week trial of either venlafaxine or a placebo with no significant difference. However, a significant treatment response defined as a 25% drop in ADHD index (measured by a self‐report scale) was achieved by venlafaxine. The interpretation of these results is limited by the short duration of follow‐up in this study. Copyright © 2012 John Wiley & Sons, Ltd.
Glycopeptidolipids: Immuno‐modulators in greasy mycobacterial cell envelope
Authors: Mukherjee Raju , Chatterji Dipankar
Published: January 2012

Species of opportunistic mycobacteria are the major causative agent for disseminating pulmonary infections in immuno‐compromised individuals. These naturally resistant strains recruit a unique type of glycolipid known as glycopeptidolipids (GPLs), noncovalently attached to the outer surface of their thick lipid rich cell envelope. Species specific GPLs constitute the chemical determinants of most nontuberculous mycobacterial serotypes, and their absence from the cell surface confers altered colony morphology, hydrophobicity, and inability to grow as biofilms. The objective of this review is to present a comprehensive account and highlight the renewed interest on this much neglected group of pleiotropic molecules with respect to their structural diversity and biosynthesis. In addition, the role of GPLs in mycobacterial survival, both intracellular and in the environment is also discussed. It also explores the possibility of identifying new targets for intervening Mycobacterium avium complex‐related infections. These antigenic molecules have been considered to play a pivotal role in immune suppression and can also induce various cytokine mediated innate immune responses, the molecular mechanism of which remains obscure. © 2012 IUBMB IUBMB Life, 2012
The recombinant kringle domain of urokinase plasminogen activator inhibits VEGF165‐induced angiogenesis of HUVECs by suppressing VEGFR2 dimerization and subsequent signal transduction
Authors: Kim Byeong Mo , Lee Dong‐Heon , Choi Hyun Jin , Lee Kee‐Ho , Kang Su Jin , Joe Young Ae , Hong Yong‐Kil , Hong Sung Hee
Published: January 2012

The recombinant kringle domain (UK1) of urokinase plasminogen activator was previously reported to exert antiangiogenic activity against Vascular Endothelial Growth Factor (VEGF)‐induced angiogenesis in both in vitro and in vivo models. In this study, we explored the molecular signaling mechanisms involved in the antiangiogenic activity of UK1 by examining VEGF signaling proteins. VEGF165 stimulates the phosphorylation of VEGF signaling molecules, and pretreatment with UK1 blocked VEGF‐induced signal transduction associated with proliferation, survival, and migration. UK1 also suppressed VEGF165‐induced activation of MMP‐2. Moreover, UK1 suppressed the phosphorylation and activation of VEGFR2 in VEGF‐stimulated human umbilical cord vein endothelial cells (HUVECs) by blocking the dimerization of VEGFR2. Overall, our findings suggest that UK1 inhibits VEGF‐induced proliferation, migration, and matrix metalloproteinase activity of HUVECs by suppressing VEGFR2 dimerization and subsequent angiogenic signals. © 2012 IUBMB IUBMB Life, 2012
Osteoblast-specific overexpression of human interleukin-7 rescues the bone mass phenotype of interleukin-7–deficient female mice
Authors: Aguila Hector L , Mun Se Hwan , Kalinowski Judith , Adams Douglas J , Lorenzo Joseph A , Lee Sun-Kyeong
Published: January 2012

Interleukin-7 is a critical cytokine for lymphoid development and a direct inhibitor of in vitro osteoclastogenesis in murine bone marrow cultures. To explore the role of IL-7 in bone, we generated transgenic mouse lines bearing the 2.3-kb rat collagen 1α1 promoter driving the expression of human IL-7 specifically in osteoblasts. In addition, we crossed these mice with IL-7–deficient mice to determine if the alterations in lymphopoiesis, bone mass, and osteoclast formation observed in the IL-7 knockout (KO) mice could be rescued by osteoblast-specific overexpression of IL-7. Here, we show that mice overexpressing human IL-7 in the osteoblast lineage showed increased trabecular bone volume in vivo by µCT and decreased osteoclast formation in vitro. Furthermore, targeted overexpression of IL-7 in osteoblasts rescued the osteopenic bone phenotype and B-cell development of IL-7 KO mice but did not have an effect on T lymphopoiesis, which occurs in the periphery. The bone phenotypes in IL-7 KO mice and targeted IL-7–overexpressing mouse models were observed only in females. These results likely reflect both direct inhibitory effects of IL-7 on osteoclastogenesis in vivo and sex-specific differences in responses to IL-7. © 2012 American Society for Bone and Mineral Research.
Fracture risk in women with breast cancer: A population-based study
Authors: Melton L Joseph , Hartmann Lynn C , Achenbach Sara J , Atkinson Elizabeth J , Therneau Terry M , Khosla Sundeep
Published: January 2012

A positive association has been reported between greater bone density and higher breast cancer risk, suggesting that these women could be at reduced risk of fracture. To estimate fracture risk among unselected community women with breast cancer and to systematically assess associations with various risk factors including breast cancer treatments, we conducted a population-based historical cohort study of 608 Olmsted County, MN, USA, women with invasive breast cancer first diagnosed in 1990 to 1999 (mean age 61.6 ± 14.8 years), who were followed for 5776 person-years. Altogether, 568 fractures were observed in 270 women (98 per 1000 person-years). Overall fracture risk was elevated 1.8-fold, but the absolute increase in risk was only 9%, and 56% of the women did not experience a fracture during follow-up. Excluding pathologic fractures (15%) and those found incidentally (24%), to allow for ascertainment bias, the standardized incidence ratio was 1.2 (95% confidence interval [CI] 0.99 to 1.3) for total fracture risk and 0.9 (95% CI 0.7 to 1.2) for osteoporotic fracture risk alone. Various breast cancer treatments were associated with an increased risk of fracture, but those associations were strongest for pathologic fractures, which were relatively more common among the women who were premenopausal when their breast cancer was diagnosed. Moreover, underlying clinical characteristics prompting different treatments may have been partially responsible for the associated fracture outcomes (indication bias). These data thus demonstrate that breast cancer patients in general are not at greatly increased risk of fracture but neither are they protected from fractures despite any determinants that breast cancer and high bone density may have in common. © 2012 American Society for Bone and Mineral Research.
Chemically modified fullerene derivatives as photosensitizers in photodynamic therapy: A first‐principles study
Authors: Zhou Cai‐Hua , Zhao Xiang
Published: January 2012

The first‐principles density functional theory (DFT) and its time‐dependent approach (TD‐DFT) are used to characterize the electronic structures and optical spectra properties of five chemically modified fullerenes. It is revealed that the metal fullerene derivatives possess not only stronger absorption bands in visible light regions than organically modified fullerene but also the large energy gaps (ΔES–T > 0.98 eV) between the singlet ground state and the triplet state, which imply their significant aspect of potential candidates as a photosensitizer. We have found that a new metal‐containing bisfullerene complexes (Pt(C60)2), with the extended conjugated π‐electrons, much degenerate orbitals and a uniform electrostatic potential surface, behave more pre‐eminent photosensitizing properties than other examined fullerene derivatives. © 2012 Wiley Periodicals, Inc.
Sonographic findings in a fatal case of transient myeloproliferative disorder
Authors: Goswami Shima , Phatak Tej
Published: January 2012

Transient myeloproliferative disorder is a unique disease in infants with Down syndrome that typically resolves spontaneously. In this report, we present a fatal case of transient myeloproliferative disorder with unusual sonographic findings including adrenal gland enlargement and thickening of the corpus callosum. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012;
IS HUMAN DEVELOPMENT MULTIDIMENSIONAL?
Authors: French Declan , Moore Michael , Canning David
Published: January 2012

Stiglitz's Commission on the Measurement of Economic Performance and Social Progress (CMEPSP) argued that well‐being is multidimensional and identified eight distinct dimensions. Conventional linear techniques confirm that a large number of dimensions are needed to describe development. In contrast, a new non‐linear technique that we introduce from chaos theory shows that a smaller number of dimensions are needed to span the development space. From the analysis, variables representing the Health, Education, Inequality and Individual Rights areas of life quality would provide a broad picture of development, whereas income per capita adds little extra information. Copyright © 2012 John Wiley & Sons, Ltd.
Global modeling of nonlinear circuits using the finite‐difference Laguerre time‐domain/alternative direction implicit finite‐difference time‐domain method with stability investigation
Authors: Mirzavand R. , Abdipour A. , Moradi G. , Movahhedi M.
Published: January 2012

This paper describes a new unconditionally stable numerical method for the full‐wave physical modeling of semiconductor devices by a combination of the finite‐difference Laguerre time‐domain (FDLTD) and alternative direction implicit finite‐difference time‐domain (ADI‐FDTD) approaches. The unconditionally stable method by using FDLTD scheme for the electromagnetic model and semi‐implicit ADI‐FDTD approach for the active model leads to a significant decrease in the full‐wave simulation time. Numerical simulations of an example transistor and a power amplifier show the efficiency of presented method for the full‐wave simulation of mm‐wave active circuits. Copyright © 2012 John Wiley & Sons, Ltd.