bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of silicone oil on the morphology and properties of polycarbonate
Authors: Kim Sung‐Ryong , Kim Dong‐Ju 
Published: May 2008

AbstractTwo types of silicone oil, poly(dimethyldiphenyl siloxane) (PDMDPS) and poly(dimethyl siloxane) (PDMS), were added to polycarbonate (PC), and the morphological, mechanical, rheological, and thermal changes of the PC/silicone oil were investigated. A scanning electron microscope showed that the dispersed droplets of the silicone oils in the PC matrix and the size of the dispersed phases were enlarged with increasing amounts of silicone oil. A transition from brittle to ductile failure was observed with increasing PDMDPS. The impact strength of neat PC at −30°C was 8 kgf cm/cm, which increased to 52 kgf cm/cm with the addition of PDMDPS. It appears that, at low temperature, the phenyl group in PDMDPS is more effective for toughening. A higher decomposition temperature and the bulkier molecular structure of PDMDPS, compared to PDMS, resulted in a smaller increase in the melt flow index of PC/PDMDPS than for PC/PDMS. The glass transition temperature, initiation temperature of thermal weight loss, and heat distortion temperature of PC/silicone oil systems were decreased with an increase in the silicone oil. The blending of PC with PDMDPS provided a practical way to develop a combination of high tensile strength and impact strength at a low temperature with applicable comprehensive properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
English‐Arabic proper‐noun transliteration‐pairs creation
Authors: Fattah Mohamed Abdel , Ren Fuji 
Published: May 2008

AbstractProper nouns may be considered the most important query words in information retrieval. If the two languages use the same alphabet, the same proper nouns can be found in either language. However, if the two languages use different alphabets, the names must be transliterated. Short vowels are not usually marked on Arabic words in almost all Arabic documents (except very important documents like the Muslim and Christian holy books). Moreover, most Arabic words have a syllable consisting of a consonant‐vowel combination (CV), which means that most Arabic words contain a short or long vowel between two successive consonant letters. That makes it difficult to create English‐Arabic transliteration pairs, since some English letters may not be matched with any romanized Arabic letter. In the present study, we present different approaches for extraction of transliteration proper‐noun pairs from parallel corpora based on different similarity measures between the English and romanized Arabic proper nouns under consideration. The strength of our new system is that it works well for low‐frequency proper noun pairs. We evaluate the new approaches presented using two different English‐Arabic parallel corpora. Most of our results outperform previously published results in terms of precision, recall, and F‐Measure.
Organic‐Inorganic Hybrid Materials for Efficient Enantioseparation Using Cellulose 3,5‐Dimethylphenylcarbamate and Tetraethyl Orthosilicate
Authors: Ikai Tomoyuki , Yamamoto Chiyo , Kamigaito Masami , Okamoto Yoshio 
Published: May 2008

AbstractThe hybrid bead‐type chiral packing material (CPM) for preparative enantioseparation has been prepared from the cellulose 3,5‐dimethylphenylcarbamate containing a small number of 3‐(triethoxysilyl)propyl groups in the presence of tetraethyl orthosilicate, by a sol‐gel reaction in an aqueous surfactant solution. The obtained hybrid bead‐type CPM was packed into a column and evaluated by high‐performance liquid chromatography. When compared with the commercially available Chiralpak IB, which is prepared by the immobilization of cellulose 3,5‐dimethylphenylcarbamate on silica gel, the hybrid bead‐type CPM was shown to exhibit a similar chiral recognition and possess a higher loading capacity.
NMR Studies on Monofunctionalized Fullerenyl Cation and Anion Encapsulating a H2 Molecule
Authors: Murata Michihisa , Ochi Yuta , Kitagawa Toshikazu , Komatsu Koichi , Murata Yasujiro 
Published: May 2008

Abstract1H NMR chemical shifts of molecular hydrogen encapsulated in dichloromethyl–C60 cation and (1‐octynyl)–C60 anion were studied to clarify the difference in magnetic shielding effects inside the fullerene cages. The signals of the H2 molecule inside both cationic and anionic C60 cages appeared at lower fields than those of the neutral counterparts. These results were interpreted based on the results of NICS calculations. It was demonstrated that the H2 molecule inside the C60 cages can serve as an excellent NMR probe of aromaticity for both cationic and anionic C60 derivatives.
Brain‐derived neurotrophic factor and autism: maternal and infant peripheral blood levels in the Early Markers for Autism (EMA) study
Authors: Croen Lisa A. , Goines Paula , Braunschweig Daniel , Yolken Robert , Yoshida Cathleen K. , Grether Judith K. , Fireman Bruce , Kharrazi Martin , Hansen Robin L. , Van de Water Judy 
Published: May 2008

AbstractTo investigate levels of brain‐derived neurotrophic factor (BDNF) in mid‐pregnancy and neonatal blood specimens as early biologic markers for autism, we conducted a population‐based case–control study nested within the cohort of infants born from July 2000 to September 2001 to women who participated in the prenatal screening program in Orange County, CA. Cases (n=84) were all children receiving services for autism at the Regional Center of Orange County. Two comparison groups from the same study population were included: children with mental retardation or developmental delay (n=49) receiving services at the same regional center, and children not receiving services for developmental disabilities, randomly sampled from the California birth certificate files (n=159), and frequency matched to autism cases on sex, birth year, and birth month. BDNF concentrations were measured in archived mid‐pregnancy and neonatal blood specimens drawn during routine prenatal and newborn screening using a highly sensitive bead‐based assay (Luminex, Biosource Human BDNF Antibody Bead Kit, Invitrogen‐Biosource, Carlsbad, CA). The concentration of BDNF in maternal mid‐pregnancy and neonatal specimens was similar across all three study groups. These data do not support previous findings of an association between BDNF and autism and suggest that the concentration of BDNF during critical periods of early neurodevelopment is not likely to be a useful biomarker for autism susceptibility.
Self–other relations in social development and autism: multiple roles for mirror neurons and other brain bases
Authors: Williams Justin H.G. 
Published: May 2008

AbstractMirror neuron system dysfunction may underlie a self–other matching impairment, which has previously been suggested to account for autism. Embodied Cognition Theory, which proposes that action provides a foundation for cognition has lent further credence to these ideas. The hypotheses of a self–other matching deficit and impaired mirror neuron function in autism have now been well supported by studies employing a range of methodologies. However, underlying mechanisms require further exploration to explain how mirror neurons may be involved in attentional and mentalizing processes. Impairments in self–other matching and mirror neuron function are not necessarily inextricably linked and it seems possible that different sub‐populations of mirror neurons, located in several regions, contribute differentially to social cognitive functions. It is hypothesized that mirror neuron coding for action–direction may be required for developing attentional sensitivity to self‐directed actions, and consequently for person‐oriented, stimulus‐driven attention. Mirror neuron networks may vary for different types of social learning such as “automatic” imitation and imitation learning. Imitation learning may be more reliant on self–other comparison processes (based on mirror neurons) that identify differences as well as similarities between actions. Differential connectivity with the amygdala–orbitofrontal system may also be important. This could have implications for developing “theory of mind,” with intentional self–other comparison being relevant to meta‐representational abilities, and “automatic” imitation being more relevant to empathy. While it seems clear that autism is associated with impaired development of embodied aspects of cognition, the ways that mirror neurons contribute to these brain–behavior links are likely to be complex.
Missing the big picture: impaired development of global shape processing in autism
Authors: Suzanne Scherf K. , Luna Beatriz , Kimchi Ruth , Minshew Nancy , Behrmann Marlene 
Published: May 2008

AbstractIndividuals with autism exhibit hypersensitivity to local elements of the input, which may interfere with the ability to group visual elements perceptually. We investigated the development of perceptual grouping abilities in high‐functioning individuals with autism (HFA) across a wide age range (8–30 years) using a classic compound letter global/local (GL) task and a more fine‐grained microgenetic prime paradigm (MPP), including both few‐ and many‐element hierarchical displays. In the GL task, contrary to the typically developing (TD) controls, HFA participants did not develop an increasing sensitivity to the global information with age. In the MPP, like the TD controls, individuals with autism at all three age groups evinced a bias to individuate the few‐element displays. However, contrary to the TD controls, the HFA group failed to show age‐related improvements in the ability to encode the global shape of the many‐element displays. In fact, across the age range, the HFA group was consistently faster than the TD controls at perceiving the local elements in these displays. These results indicate that in autism the full process of garnering shape information from perceptual grouping, which is essential for the ability to do fast and efficient object recognition and identification, never matures, and this is especially evident in adolescence when this ability begins to improve in TD individuals. The atypical development of these perceptual organizational abilities may disrupt processing of visually presented objects, which may, in turn, fundamentally impede the development of major aspects of the social and emotional behaviors in individuals with autism.
Gel formation and low‐temperature intramolecular conformation transition of a triple‐helical polysaccharide lentinan in water
Authors: Zhang Yangyang , Xu Xiaojuan , Zhang Lina 
Published: May 2008

AbstractThe gelation behavior of the triple‐helical polysaccharide lentinan fractions having different molecular weights in water at 25°C were studied by using a rheometer. The analysis of concentration and molecular weight dependence of shear stress and shear viscosity showed that aqueous lentinan is a typical shear‐thinning fluid, possessing potential as a viscosity control agent, and that a weak gel with entangled network structure formed. The dynamic oscillatory behavior of lentinan in the temperature range of 1–15°C was also investigated by rheologic method. The storage modulus G′ and complex viscosity η* increased first with decreasing temperature, and underwent a maximum centered at 7–9°C, and then decreased with further decreasing temperature. This abnormal phenomenon was ascribed to formation of rigid structure in the gel state, which was confirmed by the experimental results from micro‐DSC. The micro‐DSC curves showed that an endothermic peak appeared at 7–9°C for lentinan in water upon heating, which was attributable to the intramolecular order–disorder structure transition similar to triple‐helical polysaccharide schizophyllan. Namely, at lower temperature, the side glucose residues of lentinan (triplix II) formed a well‐organized triple‐helical structure (triplix I) through hydrogen‐bonding with the surrounding water molecules. Moreover, this conformation transition was proved to be thermally reversible. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 852–861, 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
Incidence of perforated diverticulitis and risk factors for death in a UK population
Authors: Morris C R , Harvey I M , Stebbings W S L , Hart A R 
Published: May 2008

AbstractBackgroundPerforated diverticulitis (PD) remains a serious acute abdominal condition. The aims of this study were to measure its incidence in a large UK population and to identify factors affecting outcomes.MethodsComputerized searches of hospital coding databases for PD were performed in five hospitals in East Anglia, UK. Data were collected from hospital records over 5 years (1995–2000). Incidence was calculated using population data, and factors associated with mortality and morbidity were identified using univariable and multivariable testing.ResultsSome 202 patients with PD were identified, of whom 93·1 per cent underwent surgery and 24·3 per cent died. The age-adjusted adult incidence of perforation was 3·5 per 100 000 per annum, with a standardized female to male ratio of 1·3 (95 per cent confidence interval (c.i.) 1·1 to 1·5) to 1. Risk factors for death were increased age (odds ratio (OR) 3·5 (95 per cent c.i. 1·9 to 6·1)), pre-existing renal disease (OR 18·7 (1·6 to 211·4)) and pre-existing use of non-steroidal anti-inflammatory drugs (NSAIDs) (OR 3·1 (1·3 to 7·3)).ConclusionPD is uncommon, with the highest incidence in women over 65 years old. Mortality rates are high, particularly in those taking NSAIDs or with pre-existing renal impairment.
Analysis of Cibacron blue F3G‐A interaction with therapeutic proteins by MALDI‐TOF mass spectrometry
Authors: Sutkeviciute Ieva , Sereikaite Jolanta , Bumelis Vladas‐Algirdas 
Published: May 2008

AbstractThe formation of the complexes between Cibacron blue F3G‐A and two therapeutic proteins, recombinant human interferon‐α2b and recombinant human growth hormone, was investigated. The method of time‐resolved limited proteolysis coupled with MALDI‐TOF mass spectrometry was used. The analysis of peptide maps revealed that A17HR19 and L20HQLAFDTYQEFEEAYIPK38 of hGH, and R14TLMLLAQMR23 and D33RHDFGFPQEEFGNQFQK50 of hIFN‐α2b, exhibit affinity to Cibacron blue F3G‐A. Copyright © 2008 John Wiley & Sons, Ltd.
Using RNA interference to identify the different roles of SMAD2 and SMAD3 in NIH/3T3 fibroblast cells
Authors: Zheng Rong , Xiong Qi , Zuo Bo , Jiang SiWen , Li FengE , Lei MingGang , Deng ChangYan , Xiong YuanZhu 
Published: May 2008

AbstractSmad proteins are principal intracellular signaling mediators of transforming growth factor β (TGF‐β) that regulate a wide range of biological processes. However, the identities of Smad partners mediating TGF‐β signaling are not fully understood. We firstly examined the expression of Smad2 and Smad3 induced by TGF‐β 1 in normal NIH/3T3 cells. The expression of Smad2 and Smad3 was assessed by RT‐PCR and Western blotting. The results showed that the expression of Smad2 was increased after treatment with TGF‐βI, but Smad3 was more sensitive to TGF‐βI than Smad2. RNA interference (RNAi) provides a new approach for elucidation of gene function. Use of hairpin siRNA expression vectors for RNAi has provided a rapid and versatile method for assessing gene function in mammalian cells. Here, we have constructed Smad2 and Smad3 hairpin siRNA expression plasmids, and then transfected them into mouse NIH/3T3 cells. Endogenous Smad2 and Smad3 proteins decreased significantly at 48 h after transfection. We found the expression of Smad3 in Smad2‐depleted cells was increased, however, the expression of Smad2 in Smad3‐depleted cells was not changed. Consistently, the expression of Smad4 mRNA was also attenuated in Smad3‐depleted cells. From these data, we suggest that Smad3, but not Smad2, may play a key role in TGF‐β signaling. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis of a Stabilized Version of the Imidazolone DNA Lesion
Authors: Mueller Heiko , Hopfinger Mathias , Carell Thomas 
Published: May 2008

AbstractImidazolone (dIz) is an abundant, highly mutagenic, and rather unstable DNA lesion that can cause dG→dC transversion mutations. dIz is generated in DNA by a variety of oxidative processes such as type I photooxidation. Herein we report the synthesis of a carbocyclic nucleoside analogue of dIz and of DNA containing this stabilized lesion analogue. The carbocyclic modification protects this lesion analogue from anomerization. As the repair of the lesion analogue by DNA glycosylases is not possible, this analogue should allow cocrystallization studies together with wild‐type repair enzymes. Characterization of the lesion analogue was performed by using spectroscopic methods and enzymatic digestion experiments of the oligonucleotides.
Ionic Liquids and Proteases: A Clean Alliance for Semisynthesis
Authors: Wehofsky Nicole , Wespe Christian , Cerovsky Vaclav , Pech Andreas , Hoess Eva , Rudolph Rainer , Bordusa Frank 
Published: May 2008

AbstractHerein we present the first report on protease‐catalysed ligation of cleavage‐sensitive peptide and protein fragments in ionic‐liquid‐containing solvent systems. By applying the newly established [MMIM][Me2PO4]/buffer mixture as a reaction medium, significant advantages over purely aqueous or conventional organic solvent‐containing media could be identified, including in particular the use of active wild‐type proteases as biocatalysts, the suppression of any competitive proteolytic side reactions, the high turnover rates compared to classical organic solvents and the high stability of chemically labile reactants.
The Corrin Moiety of Coenzyme B12 is the Determinant for Switching the btuB Riboswitch of E. coli
Authors: Gallo Sofia , Oberhuber Michael , Sigel Roland K. O. , Kräutler Bernhard 
Published: May 2008

AbstractRiboswitches are regulatory elements in the 5′‐untranslated region (5′‐UTR) of bacterial mRNAs that bind certain metabolites with high specificity and affinity. The 202 nucleotide (nt)‐long btuB riboswitch RNA of E. coli interacts specifically with coenzyme B12 and its derivatives thereby leading to changes in the RNA structure and hence to an altered expression of the downstream btuB gene. We report the investigations of the rearrangement of the three‐dimensional structure of the btuB riboswitch upon binding to four different B12 derivatives: coenzyme B12, vitamin B12, adenosyl factor A and adenosyl‐cobinamide. In‐line probing experiments have shown that the corrin ring plays the crucial role in switching the three‐dimensional riboswitch structure. Instead, the apical ligands influence only the binding affinity of the B12 derivative to the btuB riboswitch.
Self‐Assembly of Two Different Hierarchical Nanostructures on Either Side of an Organic Supramolecular Film in One Step
Authors: Shi Naien , Yin Gui , Han Min , Jiang Lei , Xu Zheng 
Published: May 2008

AbstractWe fabricated different hierarchical organic nanostructures on each side of a supramolecular film, by using hydrogen‐bonding interactions between tetrapyridylporphyrin and benzene‐1,3,5‐tricarboxylic acid at the H2O/CHCl3 interface. The surface of the film that faces water is composed of nanoprism arrays, whereas the surface facing CHCl3 is composed of three‐dimensional sunflower‐like hierarchical micro‐ and nanostructures. FTIR spectral evidence showed that all pyridyl groups of the tetrapyridylporphyrin hydrogen bonded to the carboxylic acid groups of 1,3,5‐benzene‐tricarboxylic acid. The aggregation modes of porphyrin presented in this supramolecular film were studied by UV/Vis and fluorescence spectroscopy. Moreover, each side of the film exhibits distinct soakage properties.
Supramolecular Tandem Enzyme Assays for Multiparameter Sensor Arrays and Enantiomeric Excess Determination of Amino Acids
Authors: Bailey David M. , Hennig Andreas , Uzunova Vanya D. , Nau Werner M. 
Published: May 2008

AbstractThe coupling of an enzymatic transformation with dynamic host‐guest exchange allows the unselective binding of macrocycles to be used for highly selective analyte sensing. The resulting supramolecular tandem enzyme assays require the enzymatic substrate and its corresponding product to differ significantly in their affinity for macrocycles, for example, cation receptors, and to show a differential propensity to displace a fluorescent dye from its host‐guest complex. The enzymatic transformation results in a concomitant dye displacement that can be accurately followed by optical spectroscopy, specifically fluorescence. By exploiting this label‐free continuous enzyme assay principle with the fluorescent dye Dapoxyl and the macrocyclic host cucurbit[7]uril, a multiparameter sensor array has been designed, which is capable of detecting the presence of amino acids (e.g. histidine, arginine, lysine, and tyrosine) and their decarboxylases. Only in the presence of both, the particular amino acid and the corresponding decarboxylase, is the amine or diamine product formed. These products are more highly positively charged than the substrate, have a higher affinity for the macrocycle and, therefore, displace the dye from the complex. The extension of the high selectivity and μM sensitivity of the tandem assay principle has also allowed for the accurate measurement of D‐lysine enantiomeric excesses of up to 99.98 %, as only the L‐enantiomer is accepted by the enzyme as a substrate and is converted to the product that is responsible for the observed fluorescence signal.
The Tandem Ring‐Closing Metathesis–Isomerization Approach to 6‐Deoxyglycals
Authors: Schmidt Bernd , Biernat Anne 
Published: May 2008

AbstractProtected 3,6‐dideoxyglycals have been synthesized de novo as single isomers starting from ethyl lactate by using the tandem RCM–isomerization reaction as the key step. Different relative configurations become accessible by addition of vinyl‐ or allyl–metal compounds to protected lactaldehydes under Cram‐chelate or Felkin–Anh control. The concept is exemplified for glycals of L‐rhodinose and L‐amicetose, as well as for ring‐expanded non‐natural analogues thereof. This novel approach to glycals is also applicable to the synthesis of disaccharide glycals via a reiterative strategy, as exemplified for the dimer of L‐rhodinose and its non‐natural ring expanded analogue.