bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and evaluation of an ester‐functional alkoxyamine for nitroxide‐mediated polymerization
Authors: Greene Anna C. , Grubbs Robert B. 
Published: October 2009

AbstractThe ester‐functional alkoxyamine 2,2‐dimethyl‐3‐(1‐(4‐(methoxycarbonyl)phenyl)ethoxy)‐4‐(4‐(methoxycarbonyl)phenyl)‐3‐azapentane (2) was efficiently synthesized for use as a functional initiator in nitroxide‐mediated polymerization. Two equivalents of 1‐(4‐(methoxycarbonyl)phenyl)ethyl radical were added across the double bond of 2‐methyl‐2‐nitrosopropane to form alkoxyamine 2, which was found to control the polymerization of styrene, isoprene, and n‐butyl acrylate. The ester moieties were hydrolyzed for subsequent esterification with 1‐pyrenebutanol to form a dipyrene‐labeled initiator that was used to probe nitroxide end‐group fidelity after styrene polymerization. High retention of nitroxide was confirmed by UV‐vis studies over a range of monomer conversions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6342–6352, 2009
Multistimuli responsive grafted poly(ether tert‐amine) (gPEA): Synthesis, characterization and controlled morphology in aqueous solution
Authors: Ren Yanrong , Jiang Xuesong , Liu Rui , Yin Jie 
Published: October 2009

AbstractMultistimuli responsive grafted poly(ether tert‐amine) (gPEAs), which were comprised of poly(propylene oxide) (PPO) in backbone and poly(ethylene oxide) (PEO) as grafted chain, were successfully synthesized through nucleophilic addition/ring‐opening reaction of commercial poly(propylene glycol) diglycidyl ether and Jeffamine L100. These gPEAs exhibit very sharp response to temperature, pH and ionic strength with tunable cloud point (CP). The CP of gPEA aqueous solution increases with increasing the PEO content or decreasing pH value, varying from 27 to 77 °C. Compared with linear PEA101, gPEA110 of completely grafted structure in aqueous solution exhibits sharper response to temperature with ΔT around 1 °C. The results obtained from TEM and dynamic light scattering reveal that gPEAs are dispersed as uniform sized nano‐micelles in aqueous at room temperature, which can further aggregate into mesoglobules of complex structure at high temperature (>CP). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6353–6361, 2009
Polyamido amine dendrimers functionalized with poly(phenylenevinylene) dendrons at their periphery
Authors: Martín‐Zarco Manuela , Toribio Santiago , García‐Martínez Joaquín C. , Rodríguez‐López Julián 
Published: October 2009

AbstractA series of polyamido amine (PAMAM) dendrimers (Generations 2, 3, 4, and 6) fully functionalized at their periphery with first‐ and second‐generation poly (phenylenevinylene) (PPV) dendrons have been efficiently prepared. MALDI‐TOF mass spectrometry proved to be particularly useful for the characterization of the new hybrid dendrimers as well as for the estimation of the average number of PPV dendrons attached to the surface. The optical absorption and emission properties of these systems were studied. The materials display extremely high molar extinction coefficients and emit blue light with only slightly lower fluorescence quantum yields than the corresponding free dendrons. Self‐quenching interactions between PPV units were not observed in THF. However, the luminescence properties underwent a dramatic change when toluene was used as the solvent. The lower polarity of toluene caused shrinkage of the PAMAM structure and brought the PPV chromophores closer together, leading to self‐quenching interactions and excimer formation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6409–6419, 2009
Submicron films prepared from aqueous dispersions of nanoscale polymer crystals
Authors: Tong Qiong , Mecking Stefan 
Published: October 2009

AbstractThin and ultrathin films of polyethylene of variable thickness are obtained from aqueous dispersions of prefabricated nanoscale crystals by spin‐coating. Continuous films with a thickness of only 15 nm, up to 220 nm, homogeneous over hundreds of μm, or assembled discontinuous monolayers of flat‐on lamella particles were prepared, depending on the solids content of the dispersion employed, as revealed by AFM and TEM. The morphology of melt‐recrystallized films was not affected by the surfactant present. Homogeneous continuous films without undesirable dewetting were retained upon melting and recrystallization of the films upon cooling, composed of polygonal spherulites for a thicker film (220 nm), randomly grown edge‐on lamella for a 40 nm film, and dominant flat‐on lamella for a 15 nm thick film. Annealing below Tm resulted in lamella thickening, without changes of crystal orientation or structure of the particle assemblies for discontinuous monolayers. Surfactant adsorbed to the nanocrystals in the aqueous dispersion desorbs at least partially during formation of the nascent films, and upon annealing below the melting point surfactant migrates to the film‐air interface to form aggregates, which can be removed by rinsing, during which the film stays intact and structurally unaltered as revealed, amongst others, by water contact angles. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6420–6432, 2009
A comparative theoretical study of the reactivities of the Al+ and Cu+ ions toward methylamine and dimethylamine
Authors: Liu Peng , Liu Jianqiang , Zhang Dongju , Zhang Changqiao 
Published: October 2009

AbstractA very recent laser ablation‐molecular beam experiment shows that an Al+ ion can react with a single methylamine (MA, CH3NH2) or dimethylamine (DMA, (CH3)2NH) molecule to form a 1:1 ion–molecule complex Al+[CH3NH2] or Al+[(CH3)2NH)], whereas a dehydrogenated complex ion Cu+[CH3N] or Cu+[C2H5N] is detected, respectively, in the similar reaction for a Cu+ ion. Here, we show a comparative density functional theory study for the reactivities of the Al+ and Cu+ ions toward MA and DMA to reveal the intrinsic mechanism. It is found that the interactions of the Al+ ion with MA and DMA are mostly electrostatic, leading to the direct ion–molecule complexes, Al+NH2CH3 and Al+NH( CH3)2, in contrast to the non‐negligible covalent character in the corresponding Cu+‐containing complexes, Cu+NH2CH3 and Cu+NH( CH3)2. The general dehydrogenation mechanism for MA and DMA promoted by the Cu+ ion has been shown, and the preponderant structures contributing to the mass spectra of the product ions Cu+[CH3N] and Cu+[C2H5N] are rationalized as Cu+NHCH2 and Cu+N( CH2)( CH3). The presumed dehydrogenation reactions are also discussed for the Al+‐containing systems. However, the involved barriers are found to be too high to be overcome at low energy conditions. These results have rationalized all the experimental observations well. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Residue mutations in [FeFe]‐hydrogenase impedes O2 binding: A QM/MM investigation
Authors: Dogaru Daniela , Motiu Stefan , Gogonea Valentin 
Published: October 2009

Abstract[FeFe]‐hydrogenases are enzymes that reversibly catalyze the reaction of protons and electrons to molecular hydrogen, which occurs in anaerobic media. In living systems, [FeFe]‐hydrogenases are mostly used for H2 production. The [FeFe]‐hydrogenase H‐cluster is the active site, which contains two iron atoms. The latest theoretical investigations (Tye et al., Inorg Chem, 2008, 47, 2380; Liu and Hu, J Am Chem Soc, 2002, 124, 5175) advocate that the structure of di‐iron air inhibited species are either FeFeOH−, or FeFeOOH, thus O2 has to be prevented from binding to Fed in all di‐iron subcluster oxidation states in order to retain a catalytically active enzyme. By performing residue mutations1 on [FeFe]‐hydrogenases, we were able to weaken O2 binding to distal iron (Fed) of Desulfovibrio desulfuricans hydrogenase (DdH). Individual residue deletions were carried out in the 8 Å apoenzyme layer radially outward from Fed to determine what residue substitutions should be made to weaken O2 binding. Residue deletions and substitutions were performed for three di‐iron subcluster oxidation states, FeFe, FeFe, and FeFe of [FeFe]‐hydrogenase. Two deletions (ΔThr152 and ΔSer202) were found most effective in weakening O2 binding to Fed in FeFe hydrogenase (ΔGQM/MM = +5.4 kcal/mol). An increase in Gibbs energy (+2.2 and +4.4 kcal/mol) has also been found for FeFe and FeFe hydrogenase, respectively. π‐backdonation considerations for frontier molecular orbital and geometrical analyses corroborate the Gibbs energy results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Reaction mechanism of cysteine proteases model compound HSH with diketone inhibitor PhCOCOCH3−nXn, (X = F, Cl,n= 0, 1, 2)
Authors: Shankar R. , Kolandaivel P. , Senthilkumar K. 
Published: October 2009

AbstractCaspases are a family of cysteine proteases, which play a crucial role in apoptosis and inflammation. The reaction mechanisms involving the cysteine proteases model compound HSH with diketone (PhCOCOCH3‐nXn, (X = F, Cl,n= 0, 1, 2) substrate have been studied using B3LYP/6‐311+G* level of density functional theory method. The harmonic vibrational frequencies were calculated at the same level of theory used for the characterization of stationary points and zero‐point vibrational energy corrections. The condensed Fukui functions have been calculated to find the favorable reactive site for the electrophilic (f), nucleophilic (f), and radical (f) attacks in the reactants. The transition states were connected with reactants, intermediate, and products, and the minimum energy paths have been confirmed through intrinsic reaction coordinate calculation. The potential energy barrier between each step of the reactions has been calculated to find the most favorable reaction path. The binding nature of cysteine model compound with diketone substrate has been studied through the interaction energies, bond lengths, electron density, natural bond orbital, and atoms in molecules theory analysis. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Theoretical studies of some sulphonamides as corrosion inhibitors for mild steel in acidic medium
Authors: Ebenso Eno E. , Arslan Taner , Kandemi̇rlı Fatma , Love Ian , Öğretır Cemi̇l , Saracoğlu Murat , Umoren Savıour A. 
Published: October 2009

AbstractDensity functional theory (DFT) at the B3LYP/6‐31G (d,p) and BP86/CEP‐31G* basis set levels and ab initio calculations using the RHF/6‐31G (d,p) methods were performed on four sulfonamides (namely sulfaacetamide (SAM), sulfapyridine (SPY), sulfamerazine (SMR), and sulfathiazole (STI)) used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between molecular structure and their inhibition efficiencies (%IE). The order of inhibition efficiency obtained was SMR > SPY > STI > SAM which corresponded with the order of most of the calculated quantum chemical parameters namely EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), the energy gap (ΔE), the Mulliken charges on the C, O, N, S atoms, hardness (η), softness (S), polarizability (α), dipole moment (μ), total energy change (ΔET), electrophilicity (ω), electron affinity (A), ionization potential (I), the absolute electronegativity (χ), and the fraction of electrons transferred (ΔN). Quantitative structure activity relationship (QSAR) approach has been used and a correlation of the composite index of some of the quantum chemical parameters was performed to characterize the inhibition performance of the sulfonamides studied. The results showed that the %IE of the sulfonamides was closely related to some of the quantum chemical parameters but with varying degrees/order. The calculated %IE of the sulfonamides studied was found to be close to their experimental corrosion inhibition efficiencies. The experimental data obtained fits the Langmuir adsorption isotherm. The negative sign of the EHOMO values and other thermodynamic parameters obtained indicates that the data obtained supports physical adsorption mechanism. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Starch Granule Size Distribution in Grains at Different Positions on the Spike of Wheat (Triticum aestivum L.)
Authors: Dai Zhongmin 
Published: October 2009

AbstractThe present study was carried out to characterize the effects of soil water status, cultivar and grain position on starch granule size distribution. The starch granule size distribution and protein and starch content were determined from three wheat cultivars with reference to the position of the grain on the spike. The results showed that the contents of A‐, B‐ and C‐type starch granules were affected by soil water, genotype and soil water×genotype interaction. Grain position was significant for A‐ and C‐type starch granules. Genotype×grain position and soil water×genotype×grain position interactions only affected C‐type starch granules. Both basal and distal grains on middle spikelets contained three types of starch granules: smaller C‐type granules with diameters <2.0 μm, medium B‐type granules with diameters 2.0–9.8 μm and large A‐type granules with diameters >9.8 μm at maturity. Both percent volume and percent surface area distribution of starch granules in basal grains showed the typical three populations, and those in distal grains exhibited a two‐peak curve. The volume and surface area percentage of C‐type granules and protein content in basal grains were higher than that in distal grains, but those of A, B‐type granules in basal grains were lower than that in distal grains. Compared with irrigation, the percent volume and surface area of B, C‐type starch granules and protein content in basal and distal grains were significantly increased, and those of A‐type were evidently decreased in rainfed condition.
Crystallinity, Thermal and Morphological Characteristics of Resistant Starch Type III Produced by Hydrothermal Treatment of Debranched Cassava Starch
Authors: Mutungi Christopher , Rost Felix , Onyango Calvin , Jaros Doris , Rohm Harald 
Published: October 2009

AbstractCassava starch was debranched using pullulanase and the linear glucans recrystallized by incubation at 60°C or by temperature cycling at 120/60°C, and further subjected to heat‐moisture treatment (HMT). Resistant starch (RS III) contents increased from 21.4 g/100 g in the debranched starch (DS) to 67.3 g/100 g in the debranched starch incubated at 60°C (DRS) and 47.8 g/100 g in the debranched starch subjected to temperature cycling (DCS), and further to 84.8 g/100 g and 88.4% g/100 g in HMT‐DRS and HMT‐DCS, respectively. Total crystallinity varied between 31.4‐59.8% and the crystalline type was C in DS and DRS and A in DCS, HMT‐DRS and HMT‐DCS. The melting properties were characterized by broad endotherms, but the exact melting region and enthalpy were dependent on recrystallization method. The main endothermic peaks of DS and DRS occurred at 103.9 and 109.8°C, respectively, whereas DCS exhibited split endotherms at 113.6 and 138.1°C. Heat‐moisture treatment broadened the endotherms and increased their enthalpies. Scanning electron micrographs revealed surface topography differences related to size and aggregation of individual crystalline bodies.
On the selection of software defect estimation techniques
Authors: Cangussu João W. , Haider Syed W. , Cooper Kendra , Baron Michael 
Published: October 2009

AbstractEstimating the number of defects in a software product is an important and challenging problem. A multitude of estimation techniques have been proposed for defect prediction. However, not all techniques are applicable in all cases. The selection of the proper approach to use depends on multiple factors: the features of the approach; the availability of resources; and the goals for using the estimated defect data. In this paper a survey of existing estimation techniques and a decision support approach for selecting the most suitable defect estimation technique for a project, with specific goals, is proposed. The results of the ranking are a clear indication that no estimation technique provides a single, comprehensive solution; the selection must be done according to a given scenario. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of 660‐nm gallium–aluminum–arsenide low‐energy laser on nerve regeneration after acellular nerve allograft in rats
Authors: Zhang Li‐Xin , Tong Xiao‐Jie , Yuan Xiu‐Hua , Sun Xiao‐Hong , Jia Hua 
Published: October 2009

AbstractPurpose: The purpose of this study was to explore and discuss the effects of 660‐nm gallium–aluminum–arsenide low‐energy laser (GaAlAs LEL) irradiation on neural regeneration after acellular nerve allograft repair of the sciatic nerve gap in rats. Methods: Eight male and female Sprague–Dawley rats were used as nerve donors, and 32 healthy Wistar rats were randomly divided into four groups: normal control group, acellular rat sciatic nerve (ARSN) group, laser group, and autograft group. Twelve weeks after surgery, nerve conduction velocity, restoration rate of tibialis anterior wet muscle weight, myelinated nerve number, and calcitonin gene‐related peptide (CGRP) protein and mRNA expression of the spinal cord and muscle at the injury site were quantified and statistically analyzed. Results: Compared with the ARSN group, laser therapy significantly increased nerve conduction velocity, restoration rate of tibialis anterior wet muscle weight, myelinated nerve number, and CGRP protein and mRNA expression of the L4 spinal cord at the injury site. Conclusions: These findings demonstrate that 660‐nm GaAlAs LEL therapy upregulates CGRP protein and mRNA expression of the L4 spinal cord at the injury site and increases the rate of regeneration and target reinnervation after acellular nerve allograft repair of the sciatic nerve gap in rats. Low‐energy laser irradiation may be a useful, noninvasive adjunct for promoting nerve regeneration in surgically induced defects repaired with ARSN. Synapse 64:152–160, 2010. © 2009 Wiley‐Liss, Inc.
Effects of cAMP‐dependent protein kinase activator and inhibitor on in vivo rolipram binding to phosphodiesterase 4 in conscious rats
Authors: Itoh Tetsuji , Abe Kohji , Hong Jinsoo , Inoue Osamu , Pike Victor W. , Innis Robert B. , Fujita Masahiro 
Published: October 2009

AbstractRolipram is a selective inhibitor of phosphodiesterase‐4 (PDE4), and positron emission tomography (PET) using [11C]rolipram can monitor the in vivo activity of this enzyme that is part of the cAMP second messenger cascade. cAMP‐dependent protein kinase (PKA) phosphorylates PDE4 and increases both enzyme activity and affinity for rolipram. In the present PET study, we examined effects of PKA modulators in conscious rats on the binding of [11C](R)‐rolipram in comparison to the much less active enantiomer [11C](S)‐rolipram. Unilateral injection of a PKA activator (dibutyryl‐cAMP) and a PKA inhibitor (Rp‐adenosine‐3′,5′‐cyclic monophosphorothioate) into the striatum significantly increased and decreased, respectively, the binding of [11C](R)‐rolipram. These effects were not caused by changes in blood flow or delivery of radioligand to brain, since these agents had no effect on the binding of [11C](S)‐rolipram binding. These results support the value of measuring in vivo [11C](R)‐rolipram binding in brain to assess responses to physiological or pharmacological challenges to the cAMP second messenger system. Synapse 64:172–176, 2010. Published 2009 Wiley‐Liss, Inc.
N‐ethyl lidocaine (QX‐314) protects striatal neurons against ischemia: An in vitro electrophysiological study
Authors: Armogida Marta , Giustizieri Michela , Zona Cristina , Piccirilli Silvia , Nisticò Robert , Mercuri Nicola B. 
Published: October 2009

AbstractIn this study, we have investigated the neuroprotective actions of the membrane impermeable, lidocaine analog,N‐ethyl lidocaine (QX‐314) in the striatum. The effects of this drug were compared with those caused by the strictly‐related‐compound and sodium channel blocker lidocaine. To address this issue, electrophysiological recordings were performed in striatal slices, in control condition (normoxia) and during combined oxygen and glucose deprivation (in vitro ischemia). Either QX‐314 or lidocaine induced, to some extent, a protection of the permanent electrophysiological alteration (field potential loss) caused by a period (12 min) of ischemia. Thus, both compounds permitted a partial recovery of the ischemic depression of the corticostriatal transmission and reduced the amplitude of the ischemic depolarization in medium spiny neurons. However, while QX‐314, at the effective concentration of 100 μM, slightly reduced the amplitude of the excitatory field potential and did not affect the current‐evoked spikes discharge of medium spiny striatal neurons, equimolar lidocaine depressed the field potential and eliminated repetitive spikes on a depolarizing step. On the basis of these observations, our results suggest the use of QX‐314 as a neuroprotective agent in ischemic brain disorders. Synapse 64:161–168, 2010. © 2009 Wiley‐Liss, Inc.
Altered response to antidepressant treatment in FoxG1 heterozygous knockout mice
Authors: Kinsler Rebecca , Taylor Mary Morgan , Flores Natasha M. , Leffert Janine J. , Beech Robert D. 
Published: October 2009

AbstractEvidence from a variety of sources suggests that structural alterations in the brain, including neurogenesis, may play a role in both the pathogenesis of mood disorders and the mechanism of action of antidepressants. Previous studies have implicated both the transforming growth factor‐beta (TGF‐β), and the phosphatidyl inositol‐3 kinase (PI3K)‐Akt pathways in the neurogenesis‐promoting and behavioral properties of antidepressants. Forkhead box protein G1 (FoxG1) is a major regulator of both of these pathways, and FoxG1 heterozygous null mice (FoxG1+/−) have previously been reported to have deficits in adult hippocampal neurogenesis and behavioral abnormalities including deficits in contextual fear learning. However the role of FoxG1, if any, in the response to antidepressants has not been previously investigated.To investigate the role of the FoxG1 gene in the behavioral and neurogenic properties of antidepressants, we tested FoxG1+/− mice and littermate controls in two different rodent models of antidepressant action: the tail suspension test and the forced swim test. FoxG1+/− mice showed no response to antidepressants in either of these tests. These results suggest that normal levels of FoxG1 may be required for the behavioral response to antidepressants. Synapse 64:169–171, 2010. © 2009 Wiley‐Liss, Inc.
Effects of the Fas/Fas‐L pathway on fluoride‐induced apoptosis in SH‐SY5Y cells
Authors: Xu Bayi , Xu Zhixia , Xia Tao , He Ping , Gao Ping , He Weihong , Zhang Ming , Guo Lijuan , Niu Qiang , Wang Aiguo 
Published: October 2009

AbstractThe mechanisms underlying fluoride‐induced apoptosis in neurons still remain unknown. To investigate apoptosis, caspase‐3 activity, and mRNA expression of Fas, Fas‐L, and caspases (‐3 and ‐8) induced by fluoride, human neuroblastoma (SH‐SY5Y) cells were incubated with 0, 20, 40, and 80 mg/L sodium fluoride (NaF) for 24 h in vitro. The data show that cell viability in the 40 and 80 mg/L fluoride groups were significantly lower than that of the control group. The percentages of apoptosis in the 40 and 80 mg/L fluoride groups were markedly higher than those in the control group, and they increased with the increase in fluoride concentration. The activity of caspase‐3 and mRNA expression levels for Fas, Fas‐L, and caspases (‐3 and ‐8) in the 40 and 80 mg/L fluoride groups were significantly higher than those in the control group. An agonistic anti‐Fas monoclonal antibody (CH‐11) significantly augmented apoptosis induction by fluoride, showing a synergistic effect, while a Fas‐blocking antibody (ZB4) partly inhibited fluoride‐induced apoptosis of SH‐SY5Y cells. The results indicate that fluoride exposure could induce apoptosis in SH‐SY5Y cells, and the Fas/Fas‐L signaling pathway may play an important role in the process. © 2009 Wiley Periodicals, Inc. Environ Toxicol 26: 86–92, 2011.