bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoinduced Processes in a Dendritic Zn Porphyrin Structure with a Free‐Base Porphyrin Core
Authors: Flamigni Lucia , Talarico Anna Maria , Ventura Barbara , Sooambar Chloé , Solladié Nathalie 
Published: March 2006

AbstractThe photophysical characterization of a nonameric porphyrin assembly made up of a central free‐base and eight peripheral zinc porphyrins connected by flexible nucleosidic linkers, and the identification of the photoinduced processes taking place in the array, is reported. Both singlet–singlet and triplet–triplet energy transfer from the peripheral zinc porphyrins to the free‐base porphyrin core is detected. The kinetic parameters of singlet–singlet energy transfer are interpreted by assuming the existence of several nonequilibrated conformations in the array due to the flexibility of the linkages. A fast quenching of the donor beyond the time detection limit of the instrument is also hypothesized and assigned to strong interactions between the zinc chromophores in close contact which can give self‐quenching phenomena. For the zinc porphyrin triplet excited state, a triplet–triplet annihilation is detected at moderate photon flux as a consequence of multi‐excitation of the same array. Drastic reduction of the photon flux allows us to determine the triplet energy transfer rate from zinc porphyrin to free‐base porphyrin, which is the final recipient of the energy collected by the array. The decay of the triplet state of the core free‐base porphyrin is prolonged with respect to the model, indicating a shielding effect of the peripheral groups. Complexation experiments with monodentate and didentate bases have been performed in order to gain insight into the spatial arrangement of the zinc porphyrin chromophores and the proposed mechanism of self‐quenching. Association of didentate bases increases the rigidity of the multi‐porphyrin structure and improves the energy collection ability.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
In Search of Binary Hybrid Systems in Manganese Chemistry: The Synthesis, Spectroscopic and Structural Characterization, and Magnetic Properties of a New Species in the Aqueous MnII‐Quinic System
Authors: Menelaou Melita , Raptopoulou Catherine P. , Terzis Aris , Tangoulis Vassilis , Salifoglou Athanasios 
Published: March 2006

AbstractManganese is a metal with diverse (bio)chemical reactivity in aqueous media in the presence of biologically relevant ligands. Key to that reactivity is the existence of soluble and bioavailable forms of MnII across the physiological range of pH. To probe the interactions arising between MnII and the low‐molecular‐mass ligand D‐(–)‐quinic acid, research efforts were targeted at the synthetic aqueous chemistry in the requisite binary system. The pH‐specific synthetic reaction of MnII with D‐(–)‐quinic acid led to the isolation of the new species [Mn2(C7H11O6)4]n·nH2O (1). Complex 1 was characterized by elemental analysis, spectroscopic techniques (EPR, FTIR), thermal and magnetic studies, and X‐ray crystallography. The molecular lattice of 1 reveals the presence of dimeric units of MnII centers, with the quinate ligands coordinated to the metal ions through variable binding modes, indicating the diversity of chemical reactivity in the system. The octahedral MnII centers in the molecular assembly of 1 serve as chemical prototypes of the forms of interactions that most likely develop in biologically relevant fluids, similar to those encountered in plant exudates and plant cellular structures. Concurrently, the physicochemical features of 1 (from the 3D hydrogen‐bonding network to the magnetic susceptibility properties and EPR spectral results) exemplify the key features that constitute the rudiments of MnII‐organic hybrid lattices of specific functions and (bio)chemical reactivity patterns. The collective properties of 1 are discussed in the context of their occurrence in natural binary MnII‐influenced systems and advanced metal‐hybrid materials of potential applications. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Illusory and spurious correlations: distinct phenomena or joint outcomes of exemplar‐based category learning?
Authors: Meiser Thorsten , Hewstone Miles 
Published: March 2006

AbstractStereotype formation about novel groups was analyzed with trivariate stimulus distributions that were generated by group membership, valence of behavior, and a context variable. Within this stimulus setting, we manipulated the confounding role of the context variable and the distinctiveness of events in terms of their relative infrequency. The experimental procedure allowed us to analyze illusory and spurious correlations in a joint framework, to conduct focused tests for memory effects of relative infrequency and to investigate the detection of covariations with the context variable. The results revealed that illusory and spurious correlations were formed without enhanced memory for infrequent events and with existing covariations of the confounding context factor being well extracted. These observations suggest that illusory and spurious correlations can be understood without assuming specific cognitive processes that are tied to the particular characteristics of a given stimulus distribution, such as enhanced memory in the case of relative infrequency and neglect of a context variable in the case of a confounding factor. Instead, computer simulations with an exemplar‐based learning model demonstrated that exemplar‐based category learning may provide a coherent and integrative theoretical framework for illusory correlations, spurious correlations and true contingency learning in social cognition. Copyright © 2006 John Wiley & Sons, Ltd.
A Bayesian hierarchical model for local precipitation by downscaling large‐scale atmospheric circulation patterns
Authors: Mendes Jorge M. , Turkman K. F. , Corte‐Real J. 
Published: March 2006

AbstractPrecipitation over the Western part of Iberian Peninsula is known to be related to the large‐scale sea level pressure field and thus to advection of humidity into this area. The major problem is to downscale this synoptic atmospheric information to local daily precipitation patterns. One way to handle this problem is by weather‐state models, where, based on the pressure field, each day is classified into a weather state and precipitation is then modeled within each weather state via multivariate distributions.In this paper, we propose a spatiotemporal Bayesian hierarchical model for precipitation. Basic objective and novelty of the paper is to capture and model the essential spatiotemporal relationships that exist between large‐scale sea level pressure field and local daily precipitation. A specific local spatial ordering that mimics the essential large‐scale patterns is used in the likelihood. The model is then applied to a network of rain gauge stations in the river Tagus valley. The inference is then carried out using appropriate MCMC methods. Copyright © 2006 John Wiley & Sons, Ltd.
Studies on vapor phase extraction of rose oil enhanced by β‐glucosidase
Authors: Zhiping Yang , Weirong Yao , He Qian 
Published: March 2006

Abstractβ ‐Glucosidase was applied in vapor extraction of rose oil to enhance the release of aroma compounds. Before vapor extraction, the rose flower was first hydrolyzed by β‐glucosidase. The conditions of enzyme hydrolysis were optimized, including the amount of β‐glucosidase, stirring rate, time, temperature of the enzymatic reaction, the ratio of rose to buffer, and the time of vapor extraction. Compared with the aroma released from rose without enzyme hydrolysis, the odor was preferred by a panel of assessors. The distillates were analyzed by gas chromatography–mass spectrometry (GC‐MS). The amount of aroma released from rose with enzyme hydrolysis was much more than the control, by calculating the total peak area. The difference between the components of the two samples were also identified. Copyright © 2006 John Wiley & Sons, Ltd.
Developmental and skill effects on the neural correlates of semantic processing to visually presented words
Authors: Chou Tai‐Li , Booth James R. , Bitan Tali , Burman Douglas D. , Bigio Jordan D. , Cone Nadia E. , Lu Dong , Cao Fan 
Published: March 2006

AbstractFunctional magnetic resonance imaging (fMRI) was used to explore the neural correlates of semantic judgments to visual words in a group of 9‐ to 15‐year‐old children. Subjects were asked to indicate if word pairs were related in meaning. Consistent with previous findings in adults, children showed activation in bilateral inferior frontal gyri (Brodmann area [BA] 47, 45) and left middle temporal gyrus (BA 21). Words with strong semantic association elicited significantly greater activation in bilateral inferior parietal lobules (BA 40), suggesting stronger integration of highly related semantic features. By contrast, words with weak semantic association elicited greater activation in left inferior frontal gyrus (BA 45) and middle temporal gyrus (BA 21), suggesting more difficult feature search and more extensive access to semantic representations. We also examined whether age and skill explained unique variance in the patterns of activation. Increasing age was correlated with greater activation in left middle temporal gyrus (BA 21) and inferior parietal lobule (BA 40), suggesting that older children have more elaborated semantic representations and more complete semantic integration processes, respectively. Decreasing age was correlated with activation in right superior temporal gyrus (BA 22) and decreasing accuracy was correlated with activation in right middle temporal gyrus (BA 21), suggesting the engagement of ancillary systems in the right hemisphere for younger and lower‐skill children. Hum. Brain Mapping 2006. © 2006 Wiley‐Liss, Inc.
Effect of molecular weight on the transfection efficiency of novel polyurethane as a biodegradable gene vector
Authors: Shau Min‐Da , Tseng S‐Ja , Yang Tsung‐Fu , Cherng Jong‐Yuh , Chin Wei‐Kuo 
Published: March 2006

AbstractNew polyurethane 2‐diethylaminoethylamine‐polyurethane (LGEA‐PU) containing poly(ethylene glycol) segments and tertiary amines was synthesized. LGEA‐PU self‐assembled readily with the plasmid DNA (pCMV‐βgal) in HEPES buffer and was characterized by dynamic light scattering, zeta potential, atomic force microscopy, and XTT cell viability assays. To examine the effect of molecular weight of LGEA‐PU systems on transfection, LGEA‐PU systems of four different molecular weights (LGEA‐PU99, LGEA‐PU59, LGEA‐PU24, and LGEA‐PU7) were prepared. This study found that LGEA‐PU99, LGEA‐PU59, and LGEA‐PU24 were able to bind plasmid DNA and yielded positively charged complexes with a nano‐sized transfection (<200 nm). The LGEA‐PU59/DNA complexes were able to transfect COS‐7 cells in vitro with higher transfection efficiency than the other LGEA‐PU systems. These results demonstrated that molecular weights of LGEA‐PU systems had a significant effect on transferring ability, except for LGEA‐PU99, which showed the strongest DNA condensation. Examination of the cytotoxicity of PEI and LGEA‐PU systems revealed that LGEA‐PU systems had lower cytotoxicity. In this article, LGEA‐PU59 seemed to be a novel cationic polyurethane for gene delivery and an interesting candidate for further study. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
In vitro and in vivo proposal of an artificial esophagus
Authors: Marzaro Maurizio , Vigolo Simonetta , Oselladore Barbara , Conconi Maria Teresa , Ribatti Domenico , Giuliani Stefano , Nico Beatrice , Perrino Giampiero , Nussdorfer Gastone Giovanni , Parnigotto Pier Paolo 
Published: March 2006

AbstractArtificial materials and autologous tissues used for esophageal reconstruction often induce complications like stenosis and leakage at long‐term follow‐up. This study evaluates the possibility to obtain in vitro an implantable tissue‐engineered esophagus composed of homologous esophageal acellular matrix and autologous smooth muscle cells (SMCs). Acellular matrices obtained by detergent‐enzymatic method did not present any major histocompatibility complex marker and expressed bFGF as protein, showing angiogenic activity in vivo on the chick embryo chorioallantoic membrane (CAM). Moreover, they supported cell adhesion, and inasmuch as just after 24 h from seeding, the scaffold appeared completely covered by SMCs. To verify the biocompatibility of our constructs, defects created in the porcine esophageal wall were covered using homologous acellular matrices with and without cultures of autologous SMCs. At 3 week from surgery, the patches composed of only acellular matrices showed a more severe inflammatory response and were negative for α‐smooth muscle actin immunostaining. In contrast, the cell‐matrix implants presented ingrowth of SMCs, showing an early organization into small fascicules. Collectively, these results suggest that patches composed of homologous esophageal acellular matrix and autologous SMCs may represent a promising tissue‐engineering approach for the repair of esophageal injuries. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Regeneration of bicortical defects in the iliac crest of estrogen‐deficient sheep, using new biodegradable polyurethane bone graft substitutes
Authors: Gogolewski Sylwester , Gorna Katarzyna , Turner A. Simon 
Published: March 2006

AbstractPorous scaffolds for cancellous bone graft substitutes were prepared from new experimental biodegradable aliphatic polyurethane elastomers with varying hydrophilicity. The ratios of the hydrophilic‐to‐hydrophobic content in the polymers were 30–70, 50–50, and 70–30%, respectively. The hydrophilic component consisted of poly(ethylene oxide) diol and the hydrophobic component of poly(ϵ‐caprolactone) diol. To promote the materials' biological performance, the calcium complexing moiety, the polysaccharide, and vitamin D3were incorporated into the polymer chain upon synthesis. The scaffolds had an interconnected porous structure with an average pore size in the range of 300–2000 μm and pore‐to‐volume ratios of (85 ± 5)%. The bone substitutes were implanted (press‐fit) in biocortical 10 × 10 mm2defects created in the tuber coxae of 21 skeletally mature Warhill ewes, which were ovariectomized 12 months prior to implantation. At the time of euthanasia at 18 and 25 months, all the defects in the ilium implanted with polyurethane bone substitutes had healed with new bone. The extent of bone healing depended on the chemical composition of the polymer from which the implant was made, although for the same material there were animal‐related differences in healing. The structure of the newly formed cancellous bone was radiographically and histologically similar to the native bone. The implants from polymers with the incorporated calcium‐complexing additive were the most effective promoters of bone healing, followed by those with vitamin D3and polysaccharide‐containing polymer. There was no bone healing in the control defects. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Controlling biofilm formation with an N‐halamine‐based polymeric additive
Authors: Luo Jie , Chen Zhaobin , Sun Yuyu 
Published: March 2006

AbstractAn N‐halamine‐based polymeric additive, poly[(6‐morpholino‐s‐triazine‐2,4‐diyl)‐N‐chloro‐[2,2,6,6‐tetramethyl‐4‐piperidyl)imino]‐hexamethylene[(2,2,6,6–4‐piperidyl) imino]] (APA‐1), was prepared in this study. The chemical structure of APA‐1 was confirmed by iodometric titration, 1H NMR, and 13C NMR analysis. APA‐1 was incorporated into polyurethane through solvent casting. The resultant materials demonstrated potent antimicrobial functions against Staphylococcus epidermidis. Zone of inhibition studies showed that APA‐1 inactivated the bacteria through contact, without leaching out of the polyurethane samples. In vitro studies illustrated that APA‐1‐containing polyurethane could prevent the colonization and biofilm formation of S. epidermidis for at least 28 days. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Retracted: Sphingosine kinase 1 regulates pro‐inflammatory responses triggered by TNFα in primary human monocytes
Authors: Zhi Liang , Leung Bernard P. , Melendez Alirio J. 
Published: March 2006

AbstractMonocytes play an important role in inflammation, angiogenesis, and atherosclerosis. During these processes monocytes release pre‐formed proinflammatory mediators from granules, and synthesize de novo cytokines and chemokines important in the amplification of the inflammatory response. One of the most prominent triggers of inflammatory responses is the cytokine TNFα. However, the intracellular signaling cascades triggered by TNFα are not fully understood. In this study we investigated the roles of SPHK on the TNFα‐triggered responses on human primary monocytes. We show that TNFα rapidly triggers S1P generation and activation of SPHK. Moreover, our data shows that SPHK1 is the isoform activated by TNFα, and plays an essential role on the TNFα‐triggered intracellular Ca2+ signals, degranulation, cytokine production, and activation of NFκB, thus suggesting a pivotal role for SPHK1 on the proinflammatory responses triggered by TNFα. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
Increased mobilization of c‐kit+ Sca‐1+ Lin− (KSL) cells and colony‐forming units in spleen (CFU‐S) following de novo formation of a stem cell niche depends on dynamic, but not stable, membranous ossification
Authors: Nagayoshi Kazunari , Ohkawa Hiroyuki , Yorozu Keigo , Higuchi Masato , Higashi Sayumi , Kubota Naoki , Fukui Hiroyasu , Imai Nobuo , Gojo Satoshi , Hata Jun‐ichi , Kobayashi Yoshiro , Umezawa Akihiro 
Published: March 2006

AbstractStem cells are thought to inhabit in a unique microenvironment, known as “niche,” in which they undergo asymmetric cell divisions that results in reproducing both stem cells and progenies to maintain various tissues throughout life. The cells of osteoblastic lineage have been identified as a key participant in regulating the number of hematopoietic stem cells (HSCs). HSCs receive their regulatory messages from the microenvironment in the bone marrow. This would account for a reason why the localization of hematopoiesis is usually restricted in the bone marrow. To clarify the above possibility we employed a cell implantation‐based strategy with a unique osteoblast cell line (KUSA‐A1) derived from a C3H/He mouse. The implantation of KUSA‐A 1 cells resulted in the generation of ectopic bones in the subcutaneous tissues of the athymic BALB/c nu/nu mice. Subsequently the mice obtained a greater amount of the bone marrow than normal mice, and they showed an increased number of HSCs. These results indicate that the newly generated osteoblasts‐derived ectopic bones are responsible for the increase in the number of the HSC population. Furthermore, the increased number of HSCs directly correlates with both the magnitude of dynamic osteogenic process and the size of the newly generated bone or “niche.” J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
Wnt induction of chondrocyte hypertrophy through the Runx2 transcription factor
Authors: Dong Yu‐Feng , Soung Do Y. , Schwarz Edward M. , O'Keefe Regis J. , Drissi Hicham 
Published: March 2006

AbstractWe investigated the molecular mechanisms underlying canonical Wnt‐mediated regulation of chondrocyte hypertrophy using chick upper sternal chondrocytes. Replication competent avian sarcoma (RCAS) viral over‐expression of Wnt8c and Wnt9a, upregulated type X collagen (col10a1) and Runx2 mRNA expression thereby inducing chondrocyte hypertrophy. Wnt8c and Wnt9a strongly inhibited mRNA levels of Sox9 and type II collagen (col2a1). Wnt8c further enhanced canonical bone morphogenetic proteins (BMP‐2)‐induced expression of Runx2 and col10a1 while Wnt8c and Wnt9a inhibited TGF‐β‐induced expression of Sox9 and col2a1. Over‐expression of β‐catenin mimics the effect of Wnt8c and Wnt9a by upregulating Runx2, col10a1, and alkaline phosphatase (AP) mRNA levels while it inhibits col2a1 transcription. Western blot analysis shows that Wnt8c and β‐catenin also induces Runx2 protein levels in chondrocytes. Thus, our results indicate that activation of the canonical β‐catenin Wnt signaling pathway induces chondrocyte hypertrophy and maturation. We further investigated the effects of β‐catenin‐TCF/Lef on Runx2 promoter. Co‐transfection of lymphoid enhancer factor (Lef1) and β‐catenin in chicken upper sternal chondrocytes together with deletion constructs of the Runx2 promoter shows that the proximal region spanning the first 128 base pairs of this promoter is responsible for the Wnt‐mediated induction of Runx2. Mutation of the TCF/Lef binding site in the −128 fragment of the Runx2 promoter resulted in loss of its responsiveness to β‐catenin. Additionally, gel‐shift assay analyses determined the DNA/protein interaction of the TCF/Lef binding sites on the Runx2 promoter. Finally, our site‐directed mutagenesis data demonstrated that the Runx2 site on type X collagen promoter is required for canonical Wnt induction of col10a1. Altogether we demonstrate that Wnt/β‐catenin signaling is regulated by TGF‐β and BMP‐2 in chick upper sternal chondrocytes, and mediates chondrocyte hypertrophy at least partly through activation of Runx2 which in turn may induce col10a1 expression. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
p16 inhibits matrix metalloproteinase‐2 expression via suppression of Sp1‐mediated gene transcription
Authors: Wang Chie‐Hong , Chang Hui‐Chiu , Hung Wen‐Chun 
Published: March 2006

AbstractPrevious studies demonstrate that p16, a cyclin‐dependent kinase inhibitor and a tumor suppressor, may inhibit matrix metalloproteinase‐2 (MMP‐2) expression in human cancer cells to suppress tumor invasion and metastasis. However, the detailed mechanism is still unclear. Our results show that p16 inhibits MMP‐2 expression via transcriptional repression. Promoter deletion and mutation analysis indicates that p16 acts through the Sp1 transcription factor‐binding site located between −72 and −64 bp region from the transcriptional start site of the human MMP‐2 promoter to repress gene expression. DNA affinity precipitation assay (DAPA) and chromatin immuno‐precipitation (CHIP) assay demonstrate that Sp1 proteins constitutively bind to this consensus sequence in vitro and in vivo. p16 attenuates Sp1 binding to the MMP‐2 promoter to suppress gene transcription and overexpression of Sp1 may counteract p16‐induced downregulation of MMP‐2. CyclinA/CDK complex may directly phosphorylate Sp1 and enhance its DNA‐binding activity. Thus, we investigated the effect of p16 on the interaction between cyclin A and Sp1. Our results indicate that p16 induces downregulation of cyclin A and CDK2, reduces the interaction between cyclin A and Sp1, and attenuates phosphorylation of Sp1. Ectoexpression of cyclin A counteracts p16‐mdeiated inhibition of DNA binding of Sp1 and activates MMP‐2 promoter activity and mRNA expression. Collectively, our results suggest that p16 suppresses MMP‐2 by blocking Sp1‐mediated gene transcription. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.