bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonisothermal crystallization kinetics of polyamide 6 and ethylene‐co‐butyl acrylate blends
Authors: Balamurugan G. Prasath , Maiti S. N. 
Published: November 2007

AbstractThe nonisothermal melt‐crystallization behavior of PA6 and EBA blends at varying EBA content was investigated using differential scanning calorimetry at different scanning rates. Several macrokinetic models such as Avrami, Jeziorny, Ozawa, Liu, Ziabicki, and Tobin were applied to analyze the crystallization behavior thoroughly under nonisothermal conditions. The Avrami and Tobin model predicted that, for pure PA6 and PA6/EBA blends, simultaneous growth of all forms of crystal structures such as fibrillar, disc‐like, and spherulitic proceeds at an increasing nucleation rate. However, when applied to blends for isothermal crystallization, the Avrami model predicted that the crystallization process is diffusion‐controlled for pure PA6 and PA6/EBA blend containing higher content of EBA (50 phr), where the nylon‐6 chains were able to diffuse freely to crystallize under isothermal conditions. Liu model predicted that, at unit crystallization time, a higher cooling rate should be used to obtain a higher degree of crystallinity for both PA6 and PA6/EBA blends. The kinetic crystallizability of PA6 in the blends calculated using Ziabicki's approach varies depending upon the nucleation density and PA6‐rich regions present in the blend compositions. Nucleation activity of the blends estimated by Dobreva and Gutzowa method reveals that the EBA particles are inert at lower concentrations of EBA and do not act as nucleating agent for PA6 molecules in the blends. The activation energy of nonisothermal crystallization, calculated using Augis–Bennett, Kissinger, and Takhor methods indicated that the activation energy is slightly lower for the blends when compared to the neat PA6. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Microgel formation and thermo‐mechanical properties of UV‐curing unsaturated polyester acrylates
Authors: Nebioglu Ahmet , Soucek Mark D. 
Published: November 2007

AbstractThe effect of internal and terminal unsaturation on the properties of the acrylated polyester films was investigated. Four types of acrylated polyester resin were prepared using adipic acid, maleic anhydride, neopentyl glycol, trimethylolpropane, and acrylic acid. Terminal and internal double bond content as well as branching was adjusted by the molar quantities of trimethylolpropane and maleic anhydride, respectively. A reactive diluent, trimethylolpropane triacrylate (TMPTA), was also used. A three‐factor, three‐level Box‐Behnken design was used to investigate complex nonlinear relationships. Dynamic mechanical, fracture toughness, and tensile properties were evaluated with respect to the amount of terminal and internal unsaturation, and reactive diluent concentration. It was found that microgel formation extensively affects the final UV‐cured film properties. Small quantities of microgels function as micro‐support units, whereas high extent of microgelation causes phase separation through cluster formation and hence, decreases the mechanical properties. It is essential to control the extent of microgelation and phase separation to optimize product performance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Isolation and functional analysis of a 24‐residue linear α‐helical antimicrobial peptide from Korean blackish cicada, Cryptotympana dubia (Homoptera)
Authors: Park Doo‐Sang , Leem Jae Yoon , Suh Eun Young , Hur Jang Hyun , Oh Hyun‐Woo , Park Ho‐Yong 
Published: November 2007

AbstractA new antimicrobial peptide, cryptonin, was isolated and characterized from the adult Korean blackish cicada, Cryptotympana dubia. It consists of 24 amino acid residues and has a molecular weight of 2,704 Da on mass spectroscopy. The predicted α‐helical structure analysis and increased helix percent in 40% trifloroethanol of cryptonin suggests that it belongs to the typical linear α‐helix forming peptide. Binding of the biotin‐labeled cryptonin at the surface of E. coli cells and increased influx of propidium iodide in E. coli after cryptonin treatment indicates that it kills microbial cells by binding bacterial cell surfaces and disrupting the cell permeability. Cryptonin showed strong antibacterial (MIC 1.56–25 μg/ml) and antifungal (MIC 3.12–50 μg/ml) activities against tested bacteria and fungi including two antibiotic‐resistant bacterial strains; methicilin‐resistant S. aureus and vancomycin‐resistant Enterococci (MIC 25 μg/ml, each). Arch. Insect Biochem. Physiol. 66:204–213, 2007. © 2007 Wiley‐Liss, Inc.
An investigation into the native‐like properties of de novo designed cavitand‐based four‐helix bundle proteins
Authors: Huttunen‐Hennelly Heidi E. K. , Sherman John C. 
Published: November 2007

AbstractWe investigated the hydrophobic packing of two previously designed caviteins, LG2 and LG3, which differ by one Gly in the linker regions between the peptide sequence and the cavitand scaffold. We sought to diminish the putative native‐like properties of LG2 and LG3, and see if we could diagnose a change in the conformational specificity of the hydrophobic core. We replaced the leucine residues with norleucine residues at the hydrophobic positions in LG2 and LG3, to create NG2 and NG3, respectively. LG2 exhibited more dispersion, but less sharp signals than LG3 in the amide region of its 1H NMR spectrum. NG3 and NG2 were found to be slightly less helical and significantly less stable toward guanidine hydrochloride compared with their reference caviteins. The 1H NMR spectrum of NG2 was very similar to that of LG2, whereas there was a noticeable loss in the number and sharpness of the amide signals of NG3 compared with LG3. These data suggest that LG3 is very well packed; a loss in conformational specificity resulted from replacement of the leucine residues with norleucine residues. In contrast, the packing and dynamics of the hydrophobic core in LG2 were similar to those in NG2 (both more modest than LG3), as their 1H NMR spectra were virtually indistinguishable. Overall, substitution of leucine by norleucine provided an efficient, convenient, and informative probe of the packing and dynamics of our caviteins' hydrophobic cores. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 37–50, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
γ‐Zein secondary structure in solution by circular dichroism
Authors: Bicudo Tatiana C. , Bicudo Rogério C. , Forato Lucimara A. , Beltramini Leila M. , Batista Luiz A. R. , Filho Rubens Bernardes , Colnago Luiz A. 
Published: November 2007

AbstractThe proline‐rich N‐terminal domain of γ‐zein has been reported in relevant processes, which include its ability to cross the cell membranes. Evidences indicate that synthetic hexapeptide (PPPVHL), naturally found in N‐terminal portion of γ‐zein, can adopt the polyproline II (PPII) conformation in aqueous solution. The secondary structure of γ‐zein in maize protein bodies had been analyzed by solid state Fourier transform infrared and nuclear magnetic resonance spectroscopies. However, it was not possible to measure PPII content in physiological environment since the β‐sheet and PPII signals overlap in both solid state techniques. Here, the secondary structure of γ‐zein has been analyzed by circular dichroism in SDS aqueous solution with and without ditiothreitol (DTT), and in 60% of 2‐propanol and water with DTT. The results show that γ‐zein has high helical content in all solutions. The PPII conformation was present at about 7% only in water/DTT solution. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 175–178, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley. com
Web‐based analysis for student‐generated complex genetic profiles
Authors: Kass David H. , LaRoe Robert 
Published: November 2007

AbstractA simple, rapid method for generating complex genetic profiles using Alu‐based markers was recently developed for students primarily at the undergraduate level to learn more about forensics and paternity analysis. On the basis of the Cold Spring Harbor Allele Server, which provides an excellent tool for analyzing a single Alu variant, we present a new web‐based system for analyzing several genetic loci, including Hardy‐Weinberg equilibrium, genetic drift, and Fst genetic‐distance calculations, as well as analyzing eight loci profiles simultaneously for forensic purposes. By analyzing several loci, students can determine more precisely the relatedness of populations as well as develop a greater appreciation for the use of DNA markers in forensic analysis by concurrently assessing the frequencies of genotypes for eight genetic loci.
Developing a new interdisciplinary lab course for undergraduate and graduate students: Plant cells and proteins
Authors: Jez Joseph M. , Schachtman Daniel P. , Berg R. Howard , Taylor Christopher G. , Chen Sixue , Hicks Leslie M. , Jaworski Jan G. , Smith Thomas J. , Nielsen Erik , Pikaard Craig S. 
Published: November 2007

AbstractStudies of protein function increasingly use multifaceted approaches that span disciplines including recombinant DNA technology, cell biology, and analytical biochemistry. These studies rely on sophisticated equipment and methodologies including confocal fluorescence microscopy, mass spectrometry, and X‐ray crystallography that are beyond the scope of traditional laboratory courses. To equip the advanced undergraduate and beginning graduate students with an enabling base of knowledge and initial experience with advanced protein research methodologies, a laboratory course entitled Plant Cells and Proteins was developed in a partnership between Washington University and the Donald Danforth Plant Science Center in St. Louis. In this one semester course, 10–12 students obtain hands‐on experience with plant tissue culture, gene transformation, subcellular localization of fluorescent recombinant proteins using confocal microscopy, purification of affinity‐tagged recombinant proteins, isolation of total protein extracts, enzymatic assays, one‐ and two‐dimensional gel electrophoresis, MALDI‐TOF and ESI‐Q‐TOF mass spectrometry, protein crystallization, and X‐ray diffraction. The course is taught as a series of modules, each led by an expert researcher. Students are evaluated based on a series of graded written reports and tests of their mastery of key concepts, interpretations, and the limitations of the experimental methods.
Irritable bowel syndrome: symptomatic treatment versus integrative psychotherapy
Authors: Kraft Tom , Kraft David 
Published: November 2007

AbstractIrritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder thought to affect 10% to 20% of the population worldwide. Essentially the paper is in two parts. The first part of the paper investigates the world literature and a variety of up to date treatment approaches which, with the exception of cognitive‐behavioural therapy (CBT) which also has beneficial effects on patients' overall mood and bloating, are designed to manage individual symptoms of IBS. The review examines the efficacy of pharmaceutical agents (antispasmodics, antidepressants, antidiarrhoeals and the new serotonergic modifying agonists/antagonists), dietary control (fibre, lactose free products, partially hydrolyzed guar gum, peppermint oil, prebiotics and probiotics), CBT (with or without the use of an audiotape) and the standard gut‐directed hypnotherapy approach of the Manchester Model.In the second half, in sharp contrast to the symptomatic treatments, the authors give a detailed account of a 54‐year‐old female patient with refractory IBS in a setting of a phobic anxiety state. The treatment approach – a combination of psychotherapy and hypnosis – was designed to effect a complete recovery rather than to manage individual symptoms. This case study exemplifies the complex nature of IBS symptoms in relation to the patient's emotions. It was necessary for her to work through these emotional problems so that she did not need to express her intense hostility through her bowels. These problems were expressed both in the psychotherapy sessions as well as in the hypnotherapy. The patient made a full recovery and this was maintained at the follow‐up a year later. Copyright © 2007 British Society of Experimental & Clinical Hypnosis. Published by John Wiley & Sons, Ltd.
Theoretical insight into the influences of α‐substituents in aliphatic aldehydes on the enantioselectivities of aldol reactions
Authors: Fan Jian‐Fen , He Liang‐Jun , Sun Yun‐Peng 
Published: November 2007

AbstractDensity functional theory has been applied to study the influences of α‐substituents in aliphatic aldehydes on the enantioselectivities of the (S)‐proline‐catalyzed direct aldol reactions. Reaction scenarios of three kinds of aliphatic aldehydes were investigated. Four transition states associated with the stereocontrolling step of each reaction have been obtained. They are corresponding to the syn and anti arrangements of enamine intermediates and the si and re attacks to the carbonyl group of an aldehyde. The solvent effect of DMSO was investigated using self‐consistent reaction field method based on the polarizable continuum model. The computed energies of transition states explain the origin of the catalysis and enantioselectivities for these (S)‐proline‐catalyzed aldol reactions and reveal the influences of α‐substituents in aliphatic aldehydes on the enantioselectivities of these reactions. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
A Density Functional Study on the Hydrolysis Process of Non‐classical Transplatin(II) with Two Same Planar Heterocycle Amines
Authors: YUAN Qing‐Hui , ZHOU Li‐Xin 
Published: November 2007

AbstractIn the present work, the hydrolysis process of non‐classical transplatin(II) with two same planar heterocycle amines has been studied using hybrid density functional theory (B3LYP) and IEF‐PCM solvation models. Optimizations were performed at the B3LYP level using a combined basis set of (LanL2DZ+6‐31+G(d,p)) with single‐point energy evaluations using the B3LYP/6‐31++G(3df,2pd) approach in vacuo and in aqueous solution. For the obtained structures of reactants, intermediates, transition states, and products, both thermodynamic (reaction energies and Gibbs energies) and kinetic (reaction barriers) characteristics were estimated. In comparison with cisplatin, decreased activation energies were obtained. The result implies that the non‐classical transplatin with two same planar heterocycle amines increases the equatorial steric effect and lowers reaction barriers, which may assist in designing novel Pt‐based anticancer drugs.
Dynamic Assemblies and Photophysical Changes of Zinc Porphyrin Dimer Regulated by N‐Containing Ligands
Authors: ZHOU Zai‐Chun , HE Lin , ZHU Yi‐Zhou , ZHENG Jian‐Yu 
Published: November 2007

AbstractZinc porphyrin dimer (1) has been designed and synthesized as a novel host of N‐containing ligands. The assembly behavior and photophysical changes of its host‐guest complexes were evaluated by 1H NMR, fluorescence, and UV‐visible titrations, and the processes reveal that the host‐guest assembly first creates a stable sandwich complex, then an axial coordination equilibrium appears between the sandwich complex and free ligand. The changes of absorption spectra of the assembly processes rely on the stabilities of the complexes, and fluorescence quenching depends on the axial coordination equilibrium, which indicates that the axial ligation/de‐ligation dynamics is indeed a pathway from the excited state to the ground state for metalloporphyrin complexes.
Preconcentration and Determination of Copper(II) Using Octadecyl Silica Membrane Disks Modified by 1,5‐Diphenylcarhazide and Flame Atomic Absorption Spectrometry
Authors: MOGHIMI Ali 
Published: November 2007

AbstractA simple and reproducible method for the rapid extraction and determination of trace amounts of copper(II) ions using octadecyl‐bonded silica membrane disks modified by 1,5‐diphenylcarbazide (DPC) and atomic absorption spectrometry was presented, which was based on complex formation on the surface of the ENVI‐18 DISKTM disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution was efficient and quantitative. The effect of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break‐through volume was found to be about 1000 mL providing a preconcentration factor of 400. The maximum capacity of the disks was found to be (255±5) µg for Cu2+, and the limit of detection of the proposed method was 5 ng per 1000 mL. The method was applied to the extraction and recovery of copper in different water samples.
L‐Proline Catalyzed Solvent‐Free Knoevenagel Condensation for the Synthesis of 3‐Substituted Coumarins
Authors: KARADE Nandkishor. N. , GAMPAWAR Sumit V. , SHINDE Sandeep. V. , JADHAV Wamanrao. N. 
Published: November 2007

AbstractL‐Proline was utilized as an efficient organo‐catalyst for the environmentally benign synthesis of 3‐substituted coumarins by the Knoevenagel condensation of substituted 2‐hydroxybenzaldehydes with reactive methylene compounds under solvent free conditions.
New Sesquiterpene Glycosides from Culture Hairy Roots of Catharanthus roseus
Authors: CHUNG ILL‐Min , ALI Mohd , CHUN Se‐Chul , LEE Sun‐Joo , SAN Ka‐Yiu , CHRISTIE A. M. Peebles , AHMAD Ateeque 
Published: November 2007

AbstractTwo new compounds cadin‐2‐en‐1β‐ol‐1β‐D‐glucuronopyranoside (1), guaia‐1,7‐dien‐3β,13‐diol‐13α‐D‐ glucofuranoside (2) along with three known compounds have been isolated from the culture hairy roots of Catharanthus roseus. Their structures have been elucidated with the help of 500 MHz NMR using 1D and 2D spectral methods: viz: 1H and 13C NMR, 1H‐1H COSY, 1H‐13C HETCOR and DEPT aided by EIMS, FAB‐MS, HR‐FABMS and IR spectroscopy.
Kinetic Resolution of 2‐Chloro‐1‐(3,4‐dichlorophenyl)ethanol by Lipase‐Catalyzed Transesterification
Authors: WANG Ming‐Hui , LI Ya‐Feng , LIU Yong‐Jun , ZHANG Shu‐Sheng 
Published: November 2007

AbstractKinetic resolution of racemic 2‐chloro‐1‐(3,4‐dichlorophenyl)ethanol was performed by free Alcaligene sp. lipase‐catalyzed irreversible transesterification affording the (R)‐isomer with ≧ 95% ee and the (S)‐isomer with ≧ 90% ee. The activity of lipase Alcaligene sp. strongly depends on the basicity of the reaction system, and an organic base such as triethylamine can enhance the activity of the lipase and enantioselectivity markedly.
A Convenient Synthesis of 2‐Arylnaphtho[1,2‐d]oxazole Derivatives Promoted by Triethylamine
Authors: LI Hong , WEI Kun , WU Yang‐Jie 
Published: November 2007

AbstractA variety of 2‐arylnaphtho[1,2‐d]oxazole derivatives were efficiently synthesized in moderate to high yields by the reaction of aromatic aldehydes with 1‐amino‐2‐naphthol derivatives in the presence of triethylamine in refluxing ethanol in air. Seven new 2‐arylnaphtho[1,2‐d]oxazole derivatives were obtained and characterized by the spectral data and elemental analysis. In addition, the X‐ray crystal structures of 2‐[4‐(N,N‐dimethylamino)phenyl]naphtho[1,2‐d] oxzole (3d) and 1,1′‐bis(naphtho[1,2‐d]oxazol‐2‐yl)ferrocene (3n) have been determined.
Supramolecular Assemblies in Salts of 2,2′‐Biimidazole with 5‐Sulfosalicylic Acid and 3,4,5‐Trihydroxybenzoic Acid
Authors: LI Yan‐Ping , YANG Pin 
Published: November 2007

AbstractSupramolecular assemblies of 2,2′‐biimidazole with 5‐sulfosalicylic acid and 3,4,5‐trihydroxybenzoic acid, have been synthesized and characterized by single‐crystal X‐ray diffraction methods. Both the two proton‐transfer compounds of 2,2′‐biimidazole with 3‐carboxy‐4‐hydroxybenzenesulfonic acid (5‐sulfosalicylic acid, 5‐SSA) [namely bis(2‐(2‐1H‐imidazolyl)‐1H‐imidazolium) 4‐hydroxybenzene‐3‐carboxylate‐1‐sulfonate monohydrate, 2(C6H7N4)+· C7H4O6S2−·H2O, (I)] and 3,4,5‐trihydroxybenzoic acid [namely 2,2′‐bi‐1H‐imidazolium bis(3,4,5‐trihydroxybenzoate) tetrahydrate, C6H8N42+·2(C7H5O5)−·4(H2O), (II)] feature extensively hydrogen‐bonded three‐dimensional network structures having significant interlayer π‐ π interactions between the cation and anion species. In I, a 5‐SSA2− dianionic species results from deprotonation of both the sulfonic and the carboxylic acid groups, all available O‐atom acceptors interact with all cation and water molecule donors by hydrogen bonds. In II, the formula unit displays a crystallographic inversion symmetry. The structural information about the two complexes between 2,2′‐biimidazole compound and benzenecarboxylic acids obtained in this work will be particularly important for the rational design of supramolecular organic functional materials.
Expression and Purification of ZNF191(243–368) in Three Expression Systems
Authors: ZHAO Dong‐Xin , TENG Xin‐Cheng , DING Zhi‐Chun , HUANG Zhong‐Xian 
Published: November 2007

AbstractZNF191(243–368), a new human zinc finger protein, probably relates to some hereditary diseases and cancers. To obtain adequate amount of ZNF191(243–368) for the study of its property, structure and function, three different expression systems of inclusion‐body, glutathione S‐transferase (GST), and hexahistidine (6×His) were used and compared. Among these systems, the expression level of ZNF191(243–368) was increased in inclusion body system under a higher isopropylthio‐β‐D‐galactoside (IPTG) concentration, but the non‐target proteins were also increased more, which made its purification more difficult and the yield lower. The expression of His‐tag fusion protein was almost not affected by IPTG concentration, temperature and inducing time. At a high IPTG concentration the highest expression yield for GST fusion protein was obtained. And the fusion proteins can be partially purified by a single affinity chromatography step. The fusion protein systems show advantages for expression of these proteins.
Synthesis, X‐ray Structure and Aggregation Effect of Tetramethoxy Substituted Dibenzo[fg,op]naphthacene
Authors: CHENG Xiao‐Hong , FU Chang‐Jin 
Published: November 2007

AbstractTetramethoxy substituted dibenzo[fg,op]naphthacene was synthesised by using Friedel‐Crafts acylation, tandem Aldol‐Michael solvent‐free reaction and palladium catalyzed dehydrohalogenation cyclization as key steps. The X‐ray structure of the product and its aggregation effect in solvent were also reported.
Novel interaction partners of Bardet‐Biedl syndrome proteins
Authors: Oeffner F. , Moch C. , Neundorf A. , Hofmann J. , Koch M. , Grzeschik K. H. 
Published: November 2007

AbstractBardet‐Biedl syndrome (BBS) is a rare, developmental disorder characterized by six major symptoms: rod‐cone dystrophy, obesity, polydactyly, renal abnormalities, learning difficulties, and hypogonadism. Secondary features include cardiac and hepatic anomalies, metabolic disturbancies, and hearing loss. BBS is genetically heterogeneous with 12 disease genes (BBS1–BBS12) described thus far. Current data suggest a functional disturbance in ciliary function and intraflagellar transport being associated with the phenotype. However, the precise functions of the BBS proteins have yet to be elucidated. This study focuses on the detection of protein factors interacting with BBS proteins. Applying yeast two‐hybrid (Y2H) technology we found a series of novel, functionally potentially plausible binding partners of BBS1, BBS2, BBS4, and BBS7. Protein interactions were supported by coimmunoprecipitation analyses (ALDOB, EPAS1) and substantiated by colocalization studies at the subcellular level (ALDOB, EXOC7, FLOT1, KRT18, PAX2). Our work provides new insights into the understanding of BBS interactions and thus their biological function. Cell Motil. Cytoskeleton 2007. © 2007 Wiley‐Liss, Inc.