bluuebunny/crossref_metadata_2025_split huggingface dataset:
Can solving of wordchains be explained by phonological skills alone?
Authors: Asbjørnsen Arve E. , Obrzut John E. , Eikeland Ole‐Johan , Manger Terje 
Published: June 2009

AbstractThe present study focussed on the determinants for effective solving of the Wordchains Test (WCT) in a normative sample of Norwegian junior high‐school students. Forty voluntary participants from a rural school district in Western Norway completed the WCT along with tests of general intellectual capacity, single word and non‐word reading, auditory working memory, and visual scanning. All measures correlated significantly with each other except for general non‐verbal abilities were not correlated with visual scanning. A stepwise multiple regression analysis, using the WCT as the dependent variable, yielded a model that included single word reading, letter recognition, and working memory as independent variables. This model accounted for 75% of the variance in WCT performance. This finding suggests that phonological skills only have an indirect influence on WCT performance. Thus, the core deficit in dyslexia, i.e. impaired phonological skills, may be related to the development of word recognition skills, but have no direct effect on the WCT performance in a normative sample. Copyright © 2009 John Wiley & Sons, Ltd.
Implicit solution of time spectral method for periodic unsteady flows
Authors: Su Xinrong , Yuan Xin 
Published: June 2009

AbstractThe present paper investigates the implicit solution of time spectral model for periodic unsteady flows. In the time spectral model, the physical time derivative is approximated using spectral method. The robustness issues associated with implicit solution of time spectral model are analyzed and validated by numerical results. It is found that spectral approximation of the time derivative weakens the diagonal dominance property of the Jacobian matrix, resulting in the deterioration of stability and convergence speed. In this paper we propose to solve the coupled governing equations implicitly using multigrid preconditioned generalized minimal residual (GMRES) method, which demonstrates favorable convergence speed. Also it is demonstrated that the current method is insensitive to the variations of frequency and number of harmonics. Comparison of computation results with dual time step unsteady computation validates the high efficiency of the current method. Copyright © 2009 John Wiley & Sons, Ltd.
Computation of heat transfer enhancement in a plate‐fin heat exchanger with triangular inserts and delta wing vortex generator
Authors: Sachdeva Gulshan , Vasudevan R. , Kasana K. S. 
Published: June 2009

AbstractLongitudinal vortices disrupt the growth of the thermal boundary layer, thereby the vortex generators producing the longitudinal vortices are well known for the enhancement of heat transfer in compact heat exchangers. The present investigation determines the heat transfer characteristics with secondary flow analysis in plate fin triangular ducts with delta wing vortex generators. This geometrical configuration is investigated for various angles of attack of the wing i.e. 15°, 20°, 26° and 37° and Reynolds numbers 100 and 200. The constant wall temperature boundary condition is used. The solution of the complete Navier Stokes equation and the energy equation is carried out using the staggered grid arrangement. The performance of the combination of triangular secondary fins and delta wing with stamping on slant surfaces has also been studied. Copyright © 2009 John Wiley & Sons, Ltd.
Distributed cell assemblies for general lexical and category‐specific semantic processing as revealed by fMRI cluster analysis
Authors: Pulvermüller Friedemann , Kherif Ferath , Hauk Olaf , Mohr Bettina , Nimmo‐Smith Ian 
Published: June 2009

AbstractHere, we ask whether frontotemporal cortex is functionally dissociated into distributed lexical and category‐specific semantic networks. To this end, fMRI activation patterns elicited during the processing of words from different semantic categories were categorized usingk‐means cluster algorithms. Results showed a distributed pattern of inferiorfrontal, superiortemporal, and fusiform activation shared by different word categories. This shared activation contrasted with patterns of category‐specific semantic activation in widely distributed neural systems. Clustering revealed congruent functional specificity of focal area activations in frontal and temporal cortex; thus suggesting a correspondence between functional partitionings of frontocentral mirror neuron systems and those of inferiortemporal lexical and semantic circuits. Action words related to the face, arms, and legs specifically activated the motor system in a somatotopic manner, whereas form‐related words activated prefrontal areas. Similar functional specificity was evident in temporal cortex, where a different semantic topography emerged for form‐ and action‐related words. Results were replicated in a separate data set, therefore recommending fMRI cluster analysis as a reliable method for scrutinizing the brain basis of lexical, semantic, and conceptual systems in humans. As focal modules do not explain the distributed character of functionally specific clusters and their distinct topographies are at variance with general distributed processing accounts, the functionally‐homogenous distributed clusters specific to semantic types are best explained by specifically‐distributed cortical circuits which, similar to Hebbian cell assemblies, represent functional units with specific roles in cognitive processing, especially in lexical and semantic access and memory. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Mapping brain abnormalities in boys with autism
Authors: Brun Caroline C. , Nicolson Rob , Leporé Natasha , Chou Yi‐Yu , Vidal Christine N. , DeVito Timothy J. , Drost Dick J. , Williamson Peter C. , Rajakumar Nagalingam , Toga Arthur W. , Thompson Paul M. 
Published: June 2009

AbstractChildren with autism spectrum disorder (ASD) exhibit characteristic cognitive and behavioral differences, but no systematic pattern of neuroanatomical differences has been consistently found. Recent neurodevelopmental models posit an abnormal early surge in subcortical white matter growth in at least some autistic children, perhaps normalizing by adulthood, but other studies report subcortical white matter deficits. To investigate the profile of these alterations in 3D, we mapped brain volumetric differences using a relatively new method, tensor‐based morphometry. 3D T1‐weighted brain MRIs of 24 male children with ASD (age: 9.5 years ± 3.2 SD) and 26 age‐matched healthy controls (age: 10.3 ± 2.4 SD) were fluidly registered to match a common anatomical template. Autistic children had significantly enlarged frontal lobes (by 3.6% on the left and 5.1% on the right), and all other lobes of the brain were enlarged significantly, or at trend level. By analyzing the applied deformations statistically point‐by‐point, we detected significant gray matter volume deficits in bilateral parietal, left temporal and left occipital lobes (P= 0.038, corrected), trend‐level cerebral white matter volume excesses, and volume deficits in the cerebellar vermis, adjacent to volume excesses in other cerebellar regions. This profile of excesses and deficits in adjacent regions may (1) indicate impaired neuronal connectivity, resulting from aberrant myelination and/or an inflammatory process, and (2) help to understand inconsistent findings of regional brain tissue excesses and deficits in autism. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Spatial deficits in a virtual water maze in amnesic participants with hippocampal damage
Authors: Goodrich‐Hunsaker Naomi J. , Livingstone Sharon A. , Skelton Ronald W. , Hopkins Ramona O. 
Published: June 2009

AbstractThe Morris water maze is a standard paradigm for the testing of hippocampal function in laboratory animals. Virtual versions of the Morris water maze are now available and can be used to assess spatial learning and memory ability in both healthy and brain injured participants. To evaluate the importance of the hippocampus in spatial learning and memory, we tested five amnesic participants with selective hippocampal damage using a virtual water maze called the Arena Maze. The amnesic participants with hippocampal damage were impaired on the invisible platform (place) task that required them to use distal cues, but were able to navigate almost as well as comparison participants when the invisible platform was marked by a single proximal cue. These results not only confirm that the hippocampus plays a necessary role in human navigation in large‐scale environments but also provides a new link between the mnemonic and navigational roles of the hippocampus. © 2009 Wiley‐Liss, Inc.
Effect of CaTiO3–CaCO3 prepared by alkoxide method on cell response
Authors: Rodriguez Andrea P. , Inoue Miho , Tanaka Toshiyuki , Miyake Michihiro , Sfer Ana M. , Kishimoto Etsuo , Tsujigiwa Hidetsugu , Rivera Rosario S. , Nagatsuka Hitoshi 
Published: June 2009

AbstractIn recent years, calcium titanate (CaTiO3) and carbon‐containing materials have gained much attention in a number of biomedical material researches. To maximize the advantages of both materials, we developed a novel alkoxide method to get “calcium titanate with calcium carbonate” (CaTiO3–CaCO3). The objective was to evaluate the crystallinity and elemental composition of CaTiO3–CaCO3 prepared by alkoxide method, CaTiO3–aC elaborated by modified thermal decomposition method, commercially‐prepared CaTiO3, and the effect of these materials on the bone marrow stromal cell. Hydroxyapatite was used as positive control material. We examined the cellular proliferation, osteoblastic differentiation, and mineralization of KUSA/A1 cells cultured with the materials. The results showed that CaTiO3–CaCO3 and CaTiO3–aC contained evidence of calcium carbonate enhancing cell proliferation, osteoblastic differentiation, and mineralization. On the contrary, the commercially‐prepared CaTiO3 revealed absence of calcium carbonate with lower cell response than the other groups. The results indicated that calcium carbonate could play a key role in the cell response of CaTiO3 material. In conclusion, our findings suggest that CaTiO3–CaCO3 could be considered an important candidate as a biomaterial for medical and dental applications. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res 2010
Wnt antagonist SFRP3 inhibits the differentiation of mouse hepatic progenitor cells
Authors: Bi Yang , Huang Jiayi , He Yun , Zhu Gao‐Hui , Su Yuxi , He Bai‐Cheng , Luo Jinyong , Wang Yi , Kang Quan , Luo Qing , Chen Liang , Zuo Guo‐Wei , Jiang Wei , Liu Bo , Shi Qiong , Tang Min , Zhang Bing‐Qiang , Weng Yaguang , Huang Ailong , Zhou Lan , Feng Tao , Luu Hue H. , Haydon Rex C. , He Tong‐Chuan , Tang Ni 
Published: June 2009

AbstractWnt/β‐catenin pathway plays an important role in regulating embryonic development. Hepatocytes differentiate from endoderm during development. Hepatic progenitor cells (HPCs) have been isolated from fetal liver and extrahepatic tissues. Most current studies in liver development and hepatic differentiation have been focused on Wnts, β‐catenin, and their receptors. Here, we sought to determine the role of Wnt antagonists in regulating hepatic differentiation of fetal liver‐derived HPCs. Using mouse liver tissues derived from embryonic day E12.5 to postnatal day (PD) 28, we found that 13 of the 19 Wnt genes and almost all of Wnt receptors/co‐receptors were expressed in most stages. However, Wnt antagonists SFRP2, SFRP3, and Dkk2 were only detected in the early stages. We established and characterized the reversible stable HPCs derived from E14.5 mouse fetal liver (HP14.5). HP14.5 cells were shown to express high levels of early liver progenitor cell markers, but low levels or none of late liver markers. HP14.5 cells were shown to differentiate into mature hepatocytes upon dexamethasone (Dex) stimulation. Dex‐induced late marker expression and albumin promoter activity in HP14.5 cells were inhibited by exogenous expression of SFRP3. Furthermore, Dex‐induced glycogen synthesis of PAS‐positive HP14.5 cells was significantly inhibited by SFRP3. Therefore, our results have demonstrated that the expression of Wnt antagonists decreases as hepatic differentiation progresses, suggesting that a balanced Wnt signaling may be critical during mouse liver development and hepatic differentiation. J. Cell. Biochem. 108: 295–303, 2009. © 2009 Wiley‐Liss, Inc.
Computational determination of fundamental pathway and activation barriers for acetohydroxyacid synthase‐catalyzed condensation reactions of α‐keto acids
Authors: Xiong Ying , Liu Junjun , Yang Guang‐Fu , Zhan Chang‐Guo 
Published: June 2009

AbstractAcetohydroxyacid synthase (AHAS) is the first common enzyme in the biosynthetic pathway leading to the production of various branched‐chain amino acids. AHAS is recognized as a promising target for new antituberculosis drugs, antibacterial drugs, and herbicides. Extensive first‐principles quantum mechanical (QM) and hybrid quantum mechanical/molecular mechanical (QM/MM) calculations have enabled us, in this study, to uncover the fundamental reaction pathway, determine the activation barriers, and obtain valuable insights concerning the specific roles of key amino acid residues for the common steps of AHAS‐catalyzed condensation reactions of α‐keto acids. The computational results reveal that the rate‐determining step of the AHAS‐catalyzed reactions is the second reaction step and that the most important amino acid residues involved in the catalysis include Glu144′, Gln207′, Gly121′, and Gly511 that form favorable hydrogen bonds with the reaction center (consisting of atoms from the substrate and cofactor) during the reaction process. In addition, Glu144′ also accepts a proton from cofactor thiamin diphosphate (ThDP) through hydrogen bonding during the catalytic reaction. The favorable interactions between the reaction center and protein environment remarkably stabilize the transition state and, thus, lower the activation barrier for the rate‐determining reaction step by ∼20 kcal/mol. The activation barrier calculated for the rate‐determining step is in good agreement with the experimental activation barrier. The detailed structural and mechanistic insights should be valuable for rational design of novel, potent AHAS inhibitors that may be used as promising new anti‐tuberculosis drugs, antibacterial drugs, and/or herbicides to overcome drug resistance problem. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Note on asymptotically good packings
Authors: Martin Daniel M. , Rödl Vojtěch 
Published: June 2009

AbstractGiven 𝓁<k<n, a partial Steiner (n, k, 𝓁)‐system 𝒫 is a family of k‐element subsets of an n‐element set such that every 𝓁‐element subset is contained in at most one member of 𝒫. The second author, followed by several others, verified a conjecture of P. Erdős and H. Hanani stating that, for every n, there exists a partial Steiner (n, k, 𝓁)‐system of size \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}$${{\left( {1 - o\left( 1 \right)} \right)\left( {_{\ell }^{n} } \right)} \mathord{\left/ {\vphantom {{\left( {1 - o\left( 1 \right)} \right)\left( {_{\ell }^{n} } \right)} {\left( {_{\ell }^{k} } \right)}}} \right. \kern-\nulldelimiterspace} {\left( {_{\ell }^{k} } \right)}}$$\end{document}. While all known proofs involve the “semi‐random method”, in this short manuscript we use an algebraic construction (European J Combin 16(1) (1995), 35–40; Problems Control Inform Theory/Problemy Upravlen Teor Inform 12(1) (1983), 3–10) and complement it by an elementary counting argument to obtain a simple proof of the above fact. © 2009 Wiley Periodicals, Inc. J Combin Designs 17: 448–455, 2009
E2F4 expression is required for cell cycle progression of normal intestinal crypt cells and colorectal cancer cells
Authors: Garneau Hugo , Paquin Marie‐Christine , Carrier Julie C. , Rivard Nathalie 
Published: June 2009

AbstractThe generation of knock‐out mice for E2F4 gene expression has suggested a role for this transcription factor in establishing and/or maintaining the intestinal crypt compartment. Having previously demonstrated that E2F4 is cytoplasmic in quiescent‐differentiated cells but nuclear in growth factor‐stimulated proliferative cells, the present study was aimed at determining the role of E2F4 in the control of human intestinal epithelial proliferation. Results herein demonstrate that lentiviral infection of an shRNA which specifically knocked‐down E2F4 expression slowed down G1/S phase transition and the proliferation rate of normal human intestinal epithelial cells (HIEC) and of colon cancer cells. Protein expression of Cdk2, cyclins D1 and A, Cdc25A and c‐myc was markedly down‐regulated in shE2F4‐expressing cells; by contrast, expression of the cell cycle inhibitors p21Cip/Waf and p27Kip1 was increased. In addition, the expression of many genes involved in DNA synthesis was down‐regulated in shE2F4‐expressing cells, whereas no modulation in E2F1 expression was observed. A decrease in E2F4 in colon cancer cell lines also resulted in a reduction in soft‐agar growth capacity. Immunofluorescence experiments in human fetal intestine revealed that cells expressing high nuclear levels of E2F4 also expressed cyclin A protein. Lastly, E2F4 and its target cyclin A were up‐regulated and mostly nuclear in human colorectal tumor cells in comparison to the corresponding benign epithelium. These results indicate that nuclear E2F4 may be determinant in the promotion of proliferation of human intestinal epithelial crypt cells and colorectal cancer cells. J. Cell. Physiol. 221: 350–358, 2009. © 2009 Wiley‐Liss, Inc.
Neural stem cells in the developing and adult brains
Authors: Qu Qiuhao , Shi Yanhong 
Published: June 2009

AbstractNeural stem cells exist in the mammalian developing and adult nervous system. Recently, tremendous interest in the potential of neural stem cells for the treatment of neurodegenerative diseases and brain injuries has substantially promoted research on neural stem cell self‐renewal and differentiation. Multiple cell‐intrinsic regulators coordinate with the microenvironment through various signaling pathways to regulate neural stem cell maintenance, self‐renewal, and fate determination. This review focuses on essential intracellular regulators that control neural stem cell maintenance and self‐renewal in both embryonic brains and adult nervous system. These factors include the orphan nuclear receptor TLX, the high‐mobility‐group DNA binding protein Sox2, the basic helix‐loop‐helix transcription factor Hes, the tumor suppressor gene Pten, the membrane‐associated protein Numb, and its cytoplasmic homolog Numblike. The aim of this review is to summarize our current understanding of neural stem cell regulation through these important stem cell regulators. J. Cell. Physiol. 221: 5–9, 2009. © 2009 Wiley‐Liss, Inc
Chemokine‐derived peptides as carriers for gene delivery to CXCR4 expressing cells
Authors: Egorova Anna , Kiselev Anton , Hakli Marika , Ruponen Marika , Baranov Vladislav , Urtti Arto 
Published: June 2009

AbstractBackgroundCell and tissue‐specific DNA delivery can be achieved by derivatizing vehicles with a targeting ligand for certain receptor. CXCR4 is a receptor of chemokine stromal cell‐derived factor (SDF)‐1 and viral protein viral macrophage inflammatory protein (vMIP)‐II. It is expressed on some types of stem and cancer cells. The present study aimed to design and characterize the group of CXCR4 targeted peptides for receptor‐mediated gene delivery. We focused on bifunctional peptide carriers: two derived from N‐terminal sequences of SDF‐1 and one from vMIP‐II.MethodsThree synthetic chemokine‐derived peptides, designated long CDP (KPVSLSYRSPSRFFESH‐K9‐biotin), short CDP (KPVSLSYR‐K9‐biotin) and viral CDP (D‐LGASWHRPDK‐K9‐biotin), were evaluated for gene delivery to CXCR4 positive and negative cells. Oligolysine K9‐biotin was used as a control. The Lys 8 moiety binds DNA electrostatically, whereas C‐terminal lysine was modified with biotin to study intracellular uptake of the peptides. Complex formation with DNA was monitored by ethidium bromide fluorescence quenching.ResultsAll peptides condensed plasmid DNA. Gene delivery by CDP/DNA complexes is glycerol‐dependent and the level of luciferase expression with signal modified carriers was comparable with the efficacy of polyethylenimine (PEI) in CXCR4 expressing cell lines (A172, HeLa) and was ten‐ to 50‐fold higher compared to unmodified peptide. By contrast, CDP transfection efficacy on CXCR4‐negative cells (chinese hamster ovary) was much lower than in PEI. Intracellular uptake analysis of biotin‐labeled peptides indicated that CDPs entered cells more efficiently than oligolysine.ConclusionsThe small, bifunctional peptides reported in the present study may be useful in gene delivery to (and gene therapy of) the different tumors and other cells expressing CXCR4. Copyright © 2009 John Wiley & Sons, Ltd.
Enzymatic synthesis of N‐methylhistamine labeled with deuterium and tritium
Authors: Šamonina J. , Kańska M. 
Published: June 2009

AbstractThe isotopomers of Nπ‐methylhistamine (πMeHA) and Nτ‐methylhistamine (τMeHA) labeled with deuterium and tritium at the α‐carbon atom of the side chain were obtained using the enzyme histidine decarboxylase (HDC, EC 4.1.1.22) from Lactobacillus 30a. The deuterium labeled isotopomers [(αR)‐2H]‐πMeHA and [(αR)‐2H]‐τMeHA were synthesized by enzymatic decarboxylation of Nπ‐methyl‐, and Nτ‐methyl‐L‐histidines (respectively) in a fully deuteriated incubation medium. The same decarboxylation carried out in a tritiated medium resulted in tritiated [αR‐3H]‐πMeHA and [αR‐3H]‐τMeHA isotopomers of N‐methylhistamine. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis of highly pure 14C‐labelled DL‐allantoin and 13C NMR analysis of labelling integrity
Authors: Patching Simon G. 
Published: June 2009

AbstractA number of synthetic approaches are assessed to prepare allantoin labelled with 14C given certain requirements and technical limitations. A method that fulfils these criteria is described to achieve the synthesis of highly pure 14C‐labelled allantoin with the label introduced to the ureido carbonyl group in the final step by reaction of 5‐chlorohydantoin with [14C]urea. The chosen method favours high purity at the expense of radiochemical yield, which is achieved at a level of 8%. The integrity of the label is then investigated by performing an NMR analysis of 13C‐labelled allantoin synthesized by the same method. The 13C NMR spectrum confirms partial scrambling of the label to the C‐2 position by equilibration of the product via a putative bicyclic intermediate, which had been suggested by other workers. The 14C‐labelled allantoin synthesized by this method is therefore assigned as DL‐[H2N14CO/14C‐2]allantoin. This study also includes the first full characterization of a side product, 5‐hydroxy‐5‐methoxyhydantoin, obtained by the reaction of a 5‐hydroxyhydantoin intermediate with the methanol solvent. Copyright © 2009 John Wiley & Sons, Ltd.