bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and analysis of properties of a new core–shell silicon‐containing fluoroacrylate latex
Authors: Junyan Liang , Ling He , Weidong Li , Hongjie Luo 
Published: August 2009

AbstractBACKGROUND: Silicon‐containing fluoroacrylate copolymers are potential materials for use in the protection of ancient stone buildings. In the work reported in this paper, a new core–shell silicon‐containing fluoroacrylate latex was prepared through grafting of a fluoroacrylate copolymer latex with polysiloxane.RESULTS: The core–shell silicon‐containing fluoroacrylate latex was successfully synthesized by seed emulsion polymerization and octamethylcyclotetrasiloxane (D4) ring‐opening polymerization in the presence of a mixed emulsifier consisting of a non‐ionic emulsifier and a novel fluorine‐containing anionic emulsifier sodium perfluoro‐octane sulfonate. Transmission electron microscopy, X‐ray photoelectron spectroscopy, static contact angle measurements and scanning electron microscopy‐energy dispersive X‐ray analysis showed that when the D4 content was controlled at 2.84–4.36 wt%, the silicon‐containing fluoroacrylate latex presented a uniform sphere core‐shell structure and had strong hydrophobic and oleophobic characters due to the association of both fluorine and silicon atoms on the latex film surface. The film cross‐section exhibited uniform and dense microstructure without any phase segregation. Additionally, thermogravimetric analysis and tensile test results indicated that all the silicon‐containing fluoroacrylate copolymers displayed better thermal stability and higher flexibility.CONCLUSION: The synthetic core–shell silicon‐containing fluoroacrylate latex showed excellent surface properties, thermal stability and flexibility, and has encouraging prospects in application as a protective coating. Copyright © 2009 Society of Chemical Industry
Synthesis of azobenzene‐functionalized two‐arm, three‐arm and four‐arm telomers using polyfunctional chain transfer agents
Authors: Alam Md Zahangir , Ogata Tomonari , Nonaka Takamasa , Kurihara Seiji 
Published: August 2009

AbstractBACKGROUND: Star‐shaped polymers are very attractive because of their interesting properties such as reduced viscosity, good solubility, low glass transition temperature and fast response to external stimuli. The incorporation of azobenzene moieties in star‐shaped polymers could significantly widen their potential applications in various optical devices. One of the most important properties of the azobenzene chromophore is its reversible trans–cis photoisomerization induced by UV or visible light. Photoisomerization induces conformational changes in azopolymer chains, which in turn lead to macroscopic variations in chemical and physical properties of the surroundings and media.RESULTS: This study reports the synthesis of azobenzene‐functionalized two‐, three‐ and four‐arm telomers via free radical telomerization using the di‐, tri‐ and tetrafunctional chain transfer agents 1,2‐ and 1,4‐benzenedimethanethiol, trimethylolpropane‐tris(2‐mercaptoacetate) and pentaerythritol‐tetrakis(3‐mercaptopropionate), respectively, in the presence of azobisisobutyronitrile. Azotelomers were characterized using gel permeation chromatography and 1H NMR and Fourier transform infrared spectroscopy. Thermal phase transition behaviors were investigated using differential scanning calorimetry and polarized optical microscopy. Azotelomers synthesized in this study showed reversible photoisomerization and a fast generation of birefringence.CONCLUSION: Considering the photoisomerization behavior and birefringence of the two‐, three‐ and four‐arm azotelomers, it can be concluded that they could be potential candidates for use in various optical devices. Copyright © 2009 Society of Chemical Industry
Protein chip analysis of pluripotency‐associated proteins in NIH3T3 fibroblast
Authors: Ajjappala Brijesh S. , Kim Myung‐Sun , Kim Eung‐Yoon , Kim Jae‐Hwan , Kang In‐Cheol , Baek Kwang‐Hyun 
Published: August 2009

AbstractSpecific transcription factors regulate the totipotent and pluripotent capability of embryonic stem cells. Amongst these regulatory transcription factors in embryonic stem cells, Oct4 and Nanog are master factors that also have unique characteristic ability of cell‐specific pluripotency and self‐renewal. The expression of Nanog in fibroblasts confirms increased cell proliferation and transformation of foci‐forming phenotype indicative of its oncogenic potential. The expression of Oct4, interestingly, leads to transformation of non‐tumorgenic mouse into tumorigenic mouse. Our current investigation ascertains that the resultant increase in DNA synthesis and cell proliferation is the consequence of transforming the phenotype into foci formation. We used a manually curetted ProteoChip to carry out the signaling protein microarray analysis, which revealed up‐regulated expression of various proteins including FAK1, MEK1 and Raf1. Some of the proteins explain the mechanism by which Oct4 and Nanog transform the phenotype. In NIH3T3 cells expressed with mouse Oct4 (mOct4), mouse Nanog (mNanog) separately as well as together, the specific knockdown of mFAK1 inhibited morphological transformation of the cells, and their invasion activity. The mFAK1 overexpression leads to morphological transformation as shown with mOct4 and mNanog. Additionally, we showed that the ERK1/2 pathway is involved in the up‐regulation of c‐myc and cyclin D1 expression mediated by mFAK1. Our results signify that the combinatorial signaling protein‐array using biomolecular approach may possibly provide us with a new tool to understand cellular homeostasis.
Proteomic characterization of Phragmites communis in ecotypes of swamp and desert dune
Authors: Cui Suxia , Hu Jia , Yang Bin , Shi Lu , Huang Fang , Tsai Sau‐Na , Ngai Sai‐Ming , He Yikun , Zhang Jianhua 
Published: August 2009

AbstractPhragmites communis Trin. (common reed) is a recognized model plant for studying its adaptation to contrasting and harsh environments. To understand the inherent molecular basis for its remarkable resistance to combined stresses, we performed a comprehensive proteomic analysis of the leaf proteins from two ecotypes, i.e. swamp and desert dune, naturally growing in the desert region of northwestern China. First, a proteome reference map of Phragmites was established based on the swamp ecotype. Proteins were resolved by 2‐D/SDS‐PAGE and identified by MALDI‐TOF/TOF MS. In total, 177 spots were identified corresponding to 51 proteins. The major proteins identified are proteins involved in photosynthesis, glutathione and ascorbic acid metabolism as well as protein synthesis and quality control. Second, the 2‐DE profiles of the two ecotypes were compared quantitatively via DIGE analysis. Compared with swamp ecotype, 51 proteins spots are higher‐expressed and 58 protein spots are lower‐expressed by twofold or more in desert dune ecotype. Major differences were found for the proteins involved in light reaction of photosynthesis, protein biosynthesis and quality control and antioxidative reactions. The physiological significance of such differences is discussed in the context of a flow of complex events in relation to plant adaptation to combined environmental stresses.
Application of iTRAQ to catalogue the skeletal muscle proteome in pigs and assessment of effects of gender and diet dephytinization
Authors: Hakimov Hatam A. , Walters Sandra , Wright Tom C. , Meidinger Roy G. , Verschoor Chris P. , Gadish Moshe , Chiu David K. Y. , Strömvik Martina V. , Forsberg Cecil W. , Golovan Serguei P. 
Published: August 2009

AbstractIn this study iTRAQ was used to produce a highly confident catalogue of 542 proteins identified in porcine muscle (false positive<5%). To our knowledge this is the largest reported set of skeletal muscle proteins in livestock. Comparison with human muscle proteome demonstrated a low level of false positives with 83% of the proteins common to both proteomes. In addition, for the first time we assess variations in the muscle proteome caused by sexually dimorphic gene expression and diet dephytinization. Preliminary analysis identified 19 skeletal muscle proteins differentially expressed between male and female pigs (≥1.2‐fold, p<0.05), but only one of them, GDP‐dissociation inhibitor 1, was significant (p<0.05) after false discovery rate correction. Diet dephytinization affected expression of 20 proteins (p<0.05). This study would contribute to an evaluation of the suitability of the pig as a model to study human gender‐related differences in gene expression. Transgenic pigs used in this study might also serve as a useful model to understand changes in human physiology resulting from diet dephytinization.
Dinuclear Zn(II) catalysts as biomimics of RNA and DNA phosphoryl transfer enzymes: changing the medium from water to alcohol provides enzyme‐like rate enhancements
Authors: Brown R. Stan , Lu Zhong‐Lin , Liu C. Tony , Tsang Wing Yin , Edwards David R. , Neverov Alexei A. 
Published: August 2009

AbstractPhosphodiesters are notoriously hydrolytically inert compounds that are demonstrated to have large accelerations of P‐OR cleavage promoted by transition and lanthanide metal ions in methanol and ethanol media. This review commentary describes recent findings of how a simple mononuclear and a dinuclear Zn(II) complex promote the cleavage of a series of RNA models and DNA models in alcohol media. The discussion centers on the analysis of the mechanisms of cleavage, energetics of the catalytic process, on recent findings of electrophilic assistance of leaving group departure, and the observation of a rapid hydrolytic reaction of a DNA model promoted by the dinuclear Zn(II) complex in ethanol containing less than 2% water. Copyright © 2009 John Wiley & Sons, Ltd.
Design of new neutral organic super‐electron donors: a theoretical study
Authors: Wang Hua‐Jing , Shi Jing , Fang Ming , Li Zhe , Guo Qing‐Xiang 
Published: August 2009

AbstractFor the purpose of designing new functional super‐electron donors (SEDs), the structure and stability of analogous tetrathiafulvalene (TTF) compounds are investigated and compared with those of the parent TTF by quantum chemistry calculations. Density functional theory (DFT) method B3LYP in combination with the polarized continuum model (PCM) is employed to compute the standard redox potentials ($E_{{\rm redox}}^{\rm o} $) of about 80 neutral organic SEDs in acetonitrile. Theoretical models are evaluated through correlation with 40 available experimental data. Excellent agreement between the theoretical predictions and experimental data is found with a mean absolute deviation of 0.08 V. Furthermore, we designed new species related to tetraazafulvalene (TAF) and evaluated their redox potential in search of new SEDs. Copyright © 2009 John Wiley & Sons, Ltd.
Systematic conformational search analysis of the SRR and RRR epimers of 7‐hydroxymatairesinol
Authors: Li Manni Giovanni , Barone Giampaolo , Duca Dario , Murzin Dmitry Yu. 
Published: August 2009

AbstractAn extensive and systematic conformational search was performed on the two epimers of the natural lignan 7‐hydroxymatairesinol (HMR), by means of a home‐made Systematic Conformational Search Analysis (SCSA) code, designed to select more and more stable conformers through sequential geometry optimization of trial structures at increasing levels of calculation theory. In the present case, the starting molecular structures were selected by the semi‐empirical AM1 method and filtered – i.e. decreased in number by choosing the more stable species – on the basis of their energy calculated by the HF method and the 6‐31G(d) basis set. The geometries obtained were further refined by performing density functional theory (DFT) optimizations, using the B3LYP functional and the 6‐31G(d,p) basis set, both in vacuo and in ethanol solution. This procedure allowed us to isolate, at a high level of theory, three groups of epimer conformers characterized by open, semi‐folded, and folded conformations. Moreover, the SCSA allowed us to describe a conformational space made‐up by about 20 species for each of the two epimers. The corresponding energy content of these species was within 27 kJ mol−1 from the absolute minimum found, both in vacuo and in ethanol solution. The conformational analysis, followed by the inspection of the stereochemistry of the two most stable conformers of both epimers, provides support in rationalizing the proposed reaction mechanism of the catalytic hydrogenolysis of the HMR to matairesinol (MAT). Copyright © 2009 John Wiley & Sons, Ltd.
Mechanistic studies of oxidation reactions by fluorescence spectroscopy: a critical assessment
Authors: Schmitt Alexander , Hinkeldey Babette , Hötzer Benjamin , Jung Gregor 
Published: August 2009

AbstractThe synthesis and properties of a ratiometric fluorescent dye system as a probe for the detection of oxidizing species are described. The dye consists of a strongly fluorescent Bodipy label attached to a styryl moiety. The oxidation of the exocyclic double bond by agents for syn‐ and anti‐ dihydroxylation leads to a visible change in fluorescence colour from orange to green. IR spectroscopy provides evidence for the generation of the epoxide in the reaction with peroxides, whereas a ketone and a product of unknown structure are produced in the reaction with osmiumtetroxide, each in contrast to the expected hydroxylations. Based on these first attempts, we discuss the significance of fluorescence spectroscopy to track chemical reactions at low concentrations and give a perspective of how present shortcomings can be overcome. Copyright © 2009 John Wiley & Sons, Ltd.
Fluorescent dendritic polymers and nanostructured coatings for the detection of chemical warfare agents and other analytes
Authors: Hartmann‐Thompson Claire , Keeley Douglas L. , Rousseau Joseph R. , Dvornic Petar R. 
Published: August 2009

AbstractPolyamidoamine (PAMAM) dendrimers of generations zero (G0) to four (G4), and a hyperbranched polyurea (HB‐PU), were functionalized with 1,5‐dansyl (1,5‐D), 2,5‐dansyl (2,5‐D), 2,6‐dansyl (2,6‐D) and nitrobenzofurazan (NBD) fluorophores that change their fluorescence emission wavelength in response to chemical environment, and the resulting dendritic polymers were characterized by MALDI‐TOF mass spectrometry, 1H NMR, 13C NMR, and fluorescence spectroscopy. Fluorophore‐functionalized dendritic polymers were then reacted further with 3‐acryloxypropyldimethoxymethylsilane (AOP‐DMOMS) at various fluorophore to DMOMS substitution ratios. The resulting materials were cast onto glass slides, and cured into robust nanostructured coatings. Coatings with 50% fluorophore–50% DMOMS substitution showed the strongest fluorescence and the best physical properties. Coated coupons were tested against a wide range of analytes including the chemical warfare agent simulants dimethyl methylphosphonate (DMMP) and chloroethylethylsulfide (CEES), and the water‐methanol‐ethanol series. It was found that the ability of the coatings to distinguish between analytes decreased with increasing cross‐link density for both dendrimer and hyperbranched polymer‐based coatings. It was also found that the percent fluorophore substitution and the type of dendritic polymer carrying the fluorophore had no significant effect upon fluorescence emission wavelength, but fluorescence emission wavelength became less dependent upon solvent with increasing dendrimer generation and molecular mass. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5101–5115, 2009
Carboxylic‐functionalized water soluble π‐conjugated polymer: Highly selective and efficient chemosensor for mercury(II) ions
Authors: Balamurugan A. , Reddy M. L. P. , Jayakannan M. 
Published: August 2009

AbstractHere, we report a new carboxylic‐functionalized water soluble π‐conjugated polymer for selective detection of highly toxic Hg2+ in neutral pH condition. carboxylic‐functionalized thiophene containing oligophenylenevinylene was synthesized and polymerized under oxidative route to obtain water soluble polymer. Free carboxylic groups present in the π‐conjugated materials provide opportunity to use pH as external stimuli for studying secondary interaction such as hydrogen bonding and aromatic π‐stacking of the chromophores. The pH changes strongly influence on the molecular interactions in the monomer, whereas the long chain polymer was less disturbed. The polymer showed high selectivity for detecting Hg2+ ions compared with any other transition metal ions in water. The detection efficiency of the polymer was found almost 40 times higher than that of its monomeric unit. Stern‐Volmer constant for the Hg2+ ion sensing was determined through concentration dependent studies as 6.4 × 105 M−1. The carboxylic‐functionalized polymer showed reversibility in the metal‐ion detecting capabilities which was further investigated by NaCl complexation with Hg2+ complex. Both funneling of excitation energy to the Hg2+ center and also excitation energy migration through chain π‐conjugated backbone were correlated to the superior sensing characteristics of the polymer compared to its monomeric counterpart. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5144–5157, 2009
A convenient room temperature polycondensation toward hyperbranched AB2‐type all‐aromatic polyesters with phenol terminal groups
Authors: Erber Michael , Boye Susanne , Hartmann Tobias , Voit Brigitte I. , Lederer Albena 
Published: August 2009

AbstractAs a convenient alternative to the classical melt polycondensation the one‐pot solution polycondensation of suitable AB2 monomers under mild conditions has been successfully adapted to hyperbranched all‐aromatic polyester with phenol terminal groups. The polymerization was performed in solution at room temperature directly using commercially available 3,5‐dihydroxybenzoic acid as monomer and 4‐(dimethylamino) pyridinium 4‐tosylate as catalyst to suppress the formation of N‐acylurea. Different carbodiimides as coupling agents were investigated to find the optimal esterification conditions. The polymers have been characterized extensively and were compared with their well‐known analogs synthesized in melt. The characterization was carried out by NMR spectroscopy, size exclusion chromatography, and asymmetric flow‐field flow fractionation as an alternative separation technique for multifunctional polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5158–5168, 2009
Airway reactivity in children before and after stem cell transplantation
Authors: Bentur Lea , Lapidot Moshe , Livnat Galit , Hakim Fahed , Lidroneta‐Katz Claudia , Porat Iris , Vilozni Daphna , Elhasid Ronit 
Published: August 2009

AbstractStem cell transplantation (SCT) is associated with pulmonary complications. We encountered several children post‐SCT with a clinical picture suggestive of airway hyper‐reactivity (AHR) and evidence of reversible airway obstruction that was not reported pre‐transplant.We evaluated the possibility of increased AHR as assessed by methacholine challenge test (MCT) following the course of SCT, and assessed a possible correlation between AHR and pulmonary complications.This was a prospective study evaluating consecutive patients referred for SCT to the Department of Pediatric Hemato‐Oncology. Evaluation included pulmonary function test and MCT before and after SCT, and assessment of pulmonary complications.Twenty‐one of 33 patients completed the study. The mean PC20 was 14.3 ± 4.1 mg/ml prior to SCT; afterward the mean PC20 decreased to 11.2 ± 5.6 mg/ml (P = 0.018). The number of patients with airway reactivity (PC20 ≤ 8 mg/ml) increased from 2/21 patients before SCT to 8/21 patients after SCT (P = 0.043; McNemar test with Yates correction). Pulmonary complications and hospitalization were recorded in 33.3% of the patients (7/21 patients): 62.5% of the patients (5 patients) with AHR compared to 15.4% (2 patients) in the group without AHR (P = 0.041; Fisher exact test). There were 10 hospitalizations among the 8 patients with positive MCT compared to 2 hospitalizations in 13 patients with negative MCT (median 1 vs. 0, P = 0.045; Mann–Whitney U‐test).Increased airway reactivity was observed in our study following the course of SCT. Positive MCT after SCT may be associated with increased risk of pulmonary complications. Larger prospective studies are needed to evaluate the possible mechanisms responsible for increased AHR and the clinical importance of these findings. Pediatr Pulmonol. 2009; 44:845–850. © 2009 Wiley‐Liss, Inc.
Designed zinc finger protein interacting with the HIV‐1 integrase recognition sequence at 2‐LTR‐circle junctions
Authors: Sakkhachornphop Supachai , Jiranusornkul Supat , Kodchakorn Kanchanok , Nangola Sawitree , Sirisanthana Thira , Tayapiwatana Chatchai 
Published: August 2009

AbstractIntegration of HIV‐1 cDNA into the host genome is a crucial step for viral propagation. Two nucleotides, cytosine and adenine (CA), conserved at the 3′ end of the viral cDNA genome, are cleaved by the viral integrase (IN) enzyme. As IN plays a crucial role in the early stages of the HIV‐1 life cycle, substrate blockage of IN is an attractive strategy for therapeutic interference. In this study, we used the 2‐LTR‐circle junctions of HIV‐1 DNA as a model to design zinc finger protein (ZFP) targeting at the end terminal portion of HIV‐1 LTR. A six‐contiguous ZFP, namely 2LTRZFP was designed using zinc finger tools. The designed motif was expressed and purified from E. coli to determine its binding properties. Surface plasmon resonance (SPR) was used to determine the binding affinity of 2LTRZFP to its target DNA. The level of dissociation constant (Kd) was 12.0 nM. The competitive SPR confirmed that 2LTRZFP specifically interacted with its target DNA. The qualitative binding activity was subsequently determined by EMSA and demonstrated the aforementioned correlation. In addition, molecular modeling and binding energy analyses were carried out to provide structural insight into the binding of 2LTRZFP to the specific and nonspecific DNA target. It is suggested that hydrogen‐bonding interactions play a key role in the DNA recognition mechanisms of the designed ZFP. Our study suggested an alternative HIV therapeutic strategy using ZFP interference of the HIV integration process.
A note on open‐chain transfer matrices from q‐deformed su(2|2)S‐matrices
Authors: Murgan R. 
Published: August 2009

AbstractIn this note, we perform Sklyanin's construction of commuting open‐chain/boundary transfer matrices to the q‐deformed SU(2|2) bulk S‐matrix of Beisert and Koroteev and a corresponding boundary S‐matrix. This also includes a corresponding commuting transfer matrix using the graded version of the q‐deformed bulk S‐matrix. Utilizing the crossing property for the bulk S‐matrix, we argue that the transfer matrix for both graded and non‐graded versions contains a crucial factor which is essential for commutativity.