bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of heart valve development in larval zebrafish
Authors: Martin Richard Tyler , Bartman Thomas 
Published: May 2009

AbstractMalformations of the cardiac endocardial cushions (ECs) and valves are common congenital dysmorphisms in newborn infants. Many regulators of EC development have been identified, but the process of valve maturation is less well understood. Zebrafish have been used to understand cardiogenesis through 6 days postfertilization, yet mature heart valves are not present at this stage. By analyzing valve development in larval zebrafish, we identify that valve development proceeds in two phases. Valve elongation occurs through 16 dpf independently of localized cell division. Valve maturation then ensues, resulting from deposition of extracellular matrix and thickening of the valves. Whereas elongation is consistent between larvae, maturation varies based on larval size, suggesting that maturation occurs in response to mechanical forces. Taken together, our studies indicate that zebrafish valve morphogenesis occurs in the larval period, and that zebrafish may provide a unique opportunity to study epigenetic mechanisms leading to human congenital valvular disease, when studied at the appropriate developmental stages. Developmental Dynamics 238:1796–1802, 2009. © 2009 Wiley‐Liss, Inc.
Synthesis and Optical Properties of Regioisomerically Pure Alkynyl‐Bridged Bis(phthalocyanines)
Authors: García‐Frutos Eva M. , de la Torre Gema , Vázquez Purificación , Shirk James S. , Torres Tomás 
Published: May 2009

AbstractPbII ethynyl‐ and butadiynyl‐bridged bis(phthalocyaninates) 1a–d, peripherally functionalized with n‐butoxy moieties, have been synthesized by using Pd‐catalyzed cross‐coupling methodologies. Preliminary open‐aperture Z‐scan experiments with nanosecond pulses at 550 nm on solutions of PbII bis(phthalocyaninates) 1b and 1d show strong reduction of the transmission at high intensities, although an irreversible optical behaviour is observed at the experimental time scale. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Calibration of POD reduced‐order models using Tikhonov regularization
Authors: Cordier L. , El Majd B. Abou , Favier J. 
Published: May 2009

AbstractIn this paper we compare various methods of calibration that can be used in practice to improve the accuracy of reduced‐order models based on proper orthogonal decomposition. The bench mark configuration retained corresponds to a case of relatively simple dynamics: a two‐dimensional flow around a cylinder for a Reynolds number of 200. We generalize to the first and second‐order the method of calibration based on Tikhonov regularization recently used in (Physica D: Nonlinear Phenom. 2009; 238:416–427). Finally, we show that for this flow configuration this procedure is the most effective in terms of reduction of errors. Copyright © 2009 John Wiley & Sons, Ltd.
DTNBP1 is associated with imaging phenotypes in schizophrenia
Authors: Narr Katherine L. , Szeszko Philip R. , Lencz Todd , Woods Roger P. , Hamilton Liberty S. , Phillips Owen , Robinson Delbert , Burdick Katherine E. , DeRosse Pamela , Kucherlapati Raju , Thompson Paul M. , Toga Arthur W. , Malhotra Anil K. , Bilder Robert M. 
Published: May 2009

AbstractDystrobrevin binding protein 1 (DTNBP1) has been identified as putative schizophrenia susceptibility gene, but it remains unknown whether polymorphisms relate to altered cerebral structure. We examined relationships between a previously implicated DTNBP1 risk variant [P1578] and global and segmented brain tissue volumes and regional cortical thickness in schizophrenia (n = 62; 24 risk carriers) and healthy subjects (n = 42; 11 risk carriers), across ethnic groups and within Caucasians. Schizophrenia patients showed similar brain volumes, but significantly reduced brain‐size adjusted gray matter and CSF volumes and cortical thinning in a widespread neocortical distribution compared to controls. DTNBP1 risk was found associated with reduced brain volume, but not with tissue sub‐compartments. Cortical thickness, which was weakly associated with brain size, showed regional variations in association with genetic risk, although effects were dominated by highly significant genotype by diagnosis interactions over broad areas of cortex. Risk status was found associated with regional cortical thinning in patients, particularly in temporal networks, but with thickness increases in controls. DTNBP1 effects for brain volume and cortical thickness appear driven by different neurobiological processes. Smaller brain volumes observed in risk carriers may relate to previously reported DTNBP1/cognitive function relationships irrespective of diagnosis. Regional cortical thinning in patient, but not in control risk carriers, may suggest that DTNBP1 interacts with other schizophrenia‐related risk factors to affect laminar thickness. Alternatively, DTNBP1 may influence neural processes for which individuals with thicker cortex are less vulnerable. Although DTNBP1 relates to cortical thinning in schizophrenia, morphological changes in the disorder are influenced by additional genetic and/or environmental factors. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Directional anisotropy of motion responses in retinotopic cortex
Authors: Raemaekers Mathijs , Lankheet Martin J.M. , Moorman Sanne , Kourtzi Zoe , van Wezel Richard J.A. 
Published: May 2009

AbstractRecently, evidence has emerged for a radial orientation bias in early visual cortex. These results predict that in early visual cortex a tangential bias should be present for motion direction. We tested this prediction in a human imaging study, using a translating random dot pattern that slowly rotated its motion direction 360° in cycles of 54 s. In addition, polar angle and eccentricity mapping were performed. This allowed the measurement of the BOLD response across the visual representations of the different retinotopic areas. We found that, in V1, V2, and V3, BOLD responses were consistently enhanced for centrifugal and centripetal motion, relative to tangential motion. The relative magnitude of the centrifugal and centripetal response biases changed with visual eccentricity. We found no motion direction biases in MT+. These results are in line with previously observed anisotropies in motion sensitivity across the visual field. However, the observation of radial motion biases in early visual cortex is surprising considering the evidence for a radial orientation bias. An additional experiment was performed to resolve this apparent conflict in results. The additional experiment revealed that the observed motion direction biases most likely originate from anisotropies in long range horizontal connections within visual cortex. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
The association between −1304T>G polymorphism in the promoter of MKK4 gene and the risk of sporadic colorectal cancer in southern Chinese population
Authors: Wei Yisheng , Wang Lei , Lan Ping , Zhao Hongjun , Pan Zhizhong , Huang Jun , Lu Jiachun , Wang Jianping 
Published: May 2009

AbstractMKK4 (mitogen‐activated protein kinase kinase 4, NM_003010.2), which belongs to the mitogen‐activated protein kinase pathways, possesses functions in tumorigenesis. We hypothesized the genetic variants in MKK4 gene may alter its functions and thus cancer risk. In current hospital‐based case‐control study of 706 patients with sporadic colorectal cancer (CRC) and 723 sex‐age–frequency‐matched control subjects in a southern Chinese population, we genotyped two polymorphisms of MKK4 promoter (i.e., −1304T>G, rs3826392 and −1044A>T, rs3809728) and assessed their associations with the risk of sporadic CRC. Compared with −1304TT genotypes, −1304TG had a significantly decreased risk of CRC (adjusted odds ratios [OR] = 0.56; 95% CI = 0.44–0.72; p = 3.53 × 10−6), the −1304GG carriers had a further decreased risk of CRC (OR = 0.40; 95% CI = 0.23–0.70; p = 1.32 × 10−3), and there was a significant trend for an allele dose effect on risk of CRC (ptrend = 2.64 × 10−7). The decreased risk associated with −1304G variant genotypes (i.e., TG+GG) was more pronounced in the subjects older than 60 years (adjusted OR = 0.41; 95% CI = 0.29–0.57; p = 2.25 × 10−7), in ever drinkers (adjusted OR = 0.41; 95% CI = 0.28–0.59; p = 2.42 × 10−6). The age and alcohol drinking status interacted with −1304G variant genotypes on reducing cancer risk (p values for interaction were 0.015 and 0.043, respectively). Western blotting analysis showed that the levels of Mkk4 protein in sporadic CRC neoplastic tissues were significantly higher in the carriers of −1304G variant genotypes than that in those with −1304TT genotypes. However, no significant association was observed between −1044A>T polymorphism and risk of CRC. To the best of our knowledge, this is the first study of genetic variants in MKK4 and cancer susceptibility. Larger studies are needed to validate our findings. © 2009 UICC
Prospects for pluripotent stem cell‐derived cardiomyocytes in cardiac cell therapy and as disease models
Authors: Freund Christian , Mummery Christine L. 
Published: May 2009

AbstractThe derivation of embryonic stem cells (hESC) from human embryos a decade ago started a new era in perspectives for cell therapy as well as understanding human development and disease. More recently, reprogramming of somatic cells to an embryonic stem cell‐like state (induced pluripotent stem cells, iPS) presented a new milestone in this area, making it possible to derive all cells types from any patients bearing specific genetic mutations. With the development of efficient differentiation protocols we are now able to use the derivatives of pluripotent stem cells to study mechanisms of disease and as human models for drug and toxicology testing. In addition derivatives of pluripotent stem cells are now close to be used in clinical practice although for the heart, specific additional challenges have been identified that preclude short‐term application in cell therapy. Here we review techniques presently used to induce differentiation of pluripotent stem cells into cardiomyocytes and the potential these cells have as disease models and for therapy. J. Cell. Biochem. 107: 592–599, 2009. © 2009 Wiley‐Liss, Inc.
A simple construction of representable relation algebras with non‐representable completions
Authors: Ahmed Tarek Sayed 
Published: May 2009

AbstractWe give a simple new construction of representable relation algebras with non‐representable completions. Using variations on our construction, we show that the elementary closure of the class of completely representable relation algebras is not finitely axiomatizable (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Archimedean classes in integral commutative residuated chains
Authors: Horčík Rostislav , Montagna Franco 
Published: May 2009

AbstractThis paper investigates a quasi‐variety of representable integral commutative residuated lattices axiomatized by the quasi‐identity resulting from the well‐known Wajsberg identity (p → q) → q ≤ (q → p) → p if it is written as a quasi‐identity, i. e., (p → q) → q ≈ 1 ⇒ (q → p) → p ≈ 1. We prove that this quasi‐identity is strictly weaker than the corresponding identity. On the other hand, we show that the resulting quasi‐variety is in fact a variety and provide an axiomatization. The obtained results shed some light on the structure of Archimedean integral commutative residuated chains. Further, they can be applied to various subvarieties of MTL‐algebras, for instance we answer negatively Hájek's question asking whether the variety of ΠMTL‐algebras is generated by its Archimedean members (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fuzzy topology representation for MV‐algebras
Authors: Zhang Jialu , Chen Quanfa 
Published: May 2009

AbstractLet M be an MV‐algebra and ΩM be the set of all σ ‐valuations from M into the MV‐unit interval. This paper focuses on the characterization of MV‐algebras using σ ‐valuations of MV‐algebras and proves that a σ ‐complete MV‐algebra is σ ‐regular, which means that a ≤ b if and only if v (a) ≤ v (b) for any v ∈ ΩM. Then one can introduce in a natural way a fuzzy topology δ on ΩM. The representation theorem forMV‐algebras is established by means of fuzzy topology. Some properties of fuzzy topology δ and its cut topology U are investigated (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micromechanical models of the strength of a sandstone
Authors: Dormieux L. , Jeannin L. , Bemer E. , Le T. H. , Sanahuja J. 
Published: May 2009

AbstractIn this paper, the strength of a sandstone is determined from a micromechanical approach. The microstructure of the rock is described as a porous polycrystal. A von Mises criterion is used for the strength of the solid grains. The grains are surrounded by Mohr–Coulomb interfaces describing the cement phase. The macroscopic strength of the polycrystal is determined by means of nonlinear homogenization techniques. The failure mechanism of the grains is assumed to be ductile. It is combined with a failure mechanism of the interfaces, which is successively assumed to be ductile and brittle. The theoretical predictions are then compared with the experimental data. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis, characterization, and electroluminescent performance of a novel copolyfluorene containing pendant crown ether groups
Authors: Yu Juin‐Meng , Chen Yun 
Published: May 2009

AbstractCopolyfluorene PFC containing pendant crown ether moieties was prepared by the palladium‐catalyzed Suzuki coupling reaction. The photo‐physical and electrochemical properties were investigated by absorption, photoluminescence (PL) spectroscopy, and cyclic voltammetry to elucidate the influence of the crown ether groups. In film state, its PL spectra (peaked at 430 and 452 nm) show noticeable red‐shift relative to 423 and 448 nm of poly(9,9‐dihexylfluorene) (PF). Thermal annealing leads to appearance of new emission at about 520 nm which has been attributed to formation of excimer. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels of PFC were estimated to be −5.68 and −2.65 eV which contributed to balanced charges injection. Double‐layer electroluminescent device using PFC as emitting layer (ITO/PEDOT:PSS/PFC/Ca/Al) revealed maximum luminance (7910 cd/m2) and maximum luminance efficiency (2.3 cd/A) superior to those of PF device (860 cd/m2, 0.29 cd/A). Moreover, inserting a PFC layer between the PF emitting layer and calcium cathode led to reduced turn‐on voltage (4.1 V), much lower than 7.1 and 6.6 V of the double‐layer PFC and PF devices, respectively, and enhanced device performance (2800 cd/m2 and 0.53 cd/A). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2985–2995, 2009
One‐pot synthesis of ABC miktoarm star terpolymers by coupling ATRP, ROP, and click chemistry techniques
Authors: Zhang Yanfeng , Li Changhua , Liu Shiyong 
Published: May 2009

AbstractWe report on the one‐pot synthesis of well‐defined ABC miktoarm star terpolymers consisting of poly(2‐(dimethylamino)ethyl methacrylate), poly(ε‐caprolactone), and polystyrene or poly(ethylene oxide) arms, PS(‐b‐PCL)‐b‐PDMA and PEO (‐b‐PCL)‐b‐PDMA, taking advantage of the compatibility and mutual tolerability of reaction conditions (catalysts and monomers) employed for atom transfer radical polymerization (ATRP), ring‐opening polymerization (ROP), and click reactions. At first, a novel trifunctional core molecule bearing alkynyl, hydroxyl group, and bromine moieties, alkynyl(OH)Br, was synthesized via the esterification reaction of 5‐ethyl‐5‐hydroxymethyl‐2,2‐dimethyl‐1,3‐dioxane with 4‐oxo‐4‐(prop‐2‐ynyloxy)butanoic acid, followed by deprotection and monoesterification of alkynyl(OH)2 with 2‐bromoisobutyryl bromide. In the presence of trifunctional core molecule, alkynyl(OH)Br, and CuBr/PMDETA/Sn(Oct)2 catalytic mixtures, target ABC miktoarm star terpolymers, PS(‐b‐PCL)‐b‐PDMA and PEO(‐b‐PCL)‐b‐PDMA, were successfully synthesized in a one‐pot manner by simultaneously conducting the ATRP of 2‐(dimethylamino)ethyl methacrylate (DMA), ROP of ε‐caprolactone (ε‐CL), and the click reaction with azido‐terminated PS (PS‐N3) or azido‐terminated PEO (PEO‐N3). Considering the excellent tolerability of ATRP to a variety of monomers and the fast expansion of click chemistry in the design and synthesis of polymeric and biorelated materials, it is quite anticipated that the one‐pot concept can be applied to the preparation of well‐defined polymeric materials with more complex chain architectures. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3066–3077, 2009
Antitumor and immunomodulating effects of polysaccharides isolated from Solanum nigrum Linne
Authors: Li Jian , Li Qing‐Wang , Gao Da‐Wei , Han Zeng‐Sheng , Lu Wen‐Zong 
Published: May 2009

AbstractWe have examined the effects of the crude polysaccharides isolated from Solanum nigrum Linne (SNL‐P) in vitro and in vivo against U14 cervical cancer. SNL‐P showed no antiproliferative effects in vitro at a dose up to 1 mg/ml. In vivo administration with SNL‐P (90, 180, 360 mg/kg b.w., p.o.) decreased the number of ascites tumor cells and prolonged the survival time of U14 cervical‐cancer‐bearing mice. FACScan flow cytometer analysis showed that most of the ascites tumor cells were arrested in G2/M phase of cell cycle and the ratio of CD4+/CD8+ peripheral blood T‐lymphocyte subpopulations were restored following treatment of SNL‐P. Furthermore, the treatment with SNL‐P also caused a significant increment in IFN‐γ (p < 0.01, 90, 180 and 360 mg/kg b.w.) and a remarkable decrease in Il‐4 (p < 0.01, 90, 180 mg/kg b.w.; p < 0.05, 360 mg/kg b.w.) by the method of ELISA. These data showed that SNL‐P possess potent antitumor activity and SNL‐P might exert antitumor activity via activation of different immune responses in the host rather than by directly attacking cancer cells on the U14 cervical cancer bearing mice. Thus, SNL‐P could be used as an immunomodulator and an anticancer agent. Copyright © 2009 John Wiley & Sons, Ltd.
A novel 3D classification system for canine impactions—the KPG index
Authors: Kau Chung How , Pan Philip , Gallerano Ron L. , English Jeryl D. 
Published: May 2009

AbstractBackground3D cone beam imaging allows localization of impacted canines, using spatial relationships, with excellent tissue contrast. The aim of this project was to assess the degree of difficulty for the treatment of impacted canines, based on the 3D information provided by cone beam imaging.Methods3D cone beam images taken from subjects with impacted canines were obtained from a private practice and school setting.ResultsA novel measuring scale was devised, based on three different viewpoints, in order to grade the difficulty of impaction and the potential efficacy of treatment. Depending on its anatomical location, the cusp tip and the root tip are each given a number 0–5 in three dimensions taken from a pretreatment image. The sum of the cusp tip and root tip scores in the three views dictated our anticipated difficulty of treatment.ConclusionsA novel method of analysing impactions using cone beam imaging was proposed. This method utilizes the entire three views of a CBCT image. Copyright © 2009 John Wiley & Sons, Ltd.
How do networks and learning drive M&As? An institutional comparison between China and the United States
Authors: Lin Zhiang (John) , Peng Mike W. , Yang Haibin , Sun Sunny Li 
Published: May 2009

AbstractWhat drives mergers and acquisitions (M&As) in different institutional environments? This article builds on the resource dependence perspective and argues that networks, learning, and institutions represent three building blocks that can enhance our understanding of the drivers behind M&As. Specifically, we consider firms as learning actors embedded in network relations and influenced by institutional development, and compare and contrast firms' acquisition activities across the United States and China. Our findings show that there are indeed important learning and network factors that lead to M&As. More interestingly, the impact of such learning and network factors varies sharply across countries with different market‐based institutions. Copyright © 2009 John Wiley & Sons, Ltd.
Senescent Growth Arrest in Mesenchymal Stem Cells Is Bypassed by Wip1-Mediated Downregulation of Intrinsic Stress Signaling Pathways
Authors: Lee Ji-Seon , Lee Mi-Ok , Moon Bo-Hyun , Shim Sung Han , Fornace Albert J. , Cha Hyuk-Jin 
Published: May 2009

AbstractHuman mesenchymal stem cells (hMSCs) have been widely studied as a source of primary adult stem cells for cell therapy because of their multidifferentiation potential; however, the growth arrest (also known as “premature senescence”) often found in hMSCs cultured in vitro has been a major obstacle to the in-depth characterization of these cells. In addition, the inability to maintain constant cell growth hampers the development of additional genetic modifications aimed at achieving desired levels of differentiation to specific tissues; however, the molecular mechanisms that govern this phenomenon remain unclear, with the exception of a few studies demonstrating that induction of p16INK4a is responsible for this senescence-like event. Here, we observed that the premature growth arrest in hMSCs occurs in parallel with the induction of p16INK4a, following abrogation of inhibitory phosphorylation of retinoblastoma protein. These stress responses were concurrent with increased formation of reactive oxygen species (ROSs) from mitochondria and increased p38 mitogen-activated protein kinase (MAPK) activity. The introduction of Wip1 (wild-type p53 inducible phosphatase-1), a well-studied stress modulator, significantly lowered p16INK4a expression and led to p38 MAPK inactivation, although it failed to affect the levels of ROSs. Moreover, the suppression of stress responses by Wip1 apparently extended the life span of hMSCs, compared with control conditions, while maintaining their multilineage differentiation potential. Based on these results, we suggest that senescent growth arrest in hMSCs may result from activation of stress signaling pathways and consequent onset of stress responses, due in part to ROS production during prolonged in vitro culture.Disclosure of potential conflicts of interest is found at the end of this article.
Moral Distress in Rehabilitation Professionals: Results From a Hospital Ethics Survey
Authors: Mukherjee Debjani , Brashler Rebecca , Savage Teresa A. , Kirschner Kristi L. 
Published: May 2009

ObjectiveMoral distress in the rehabilitation setting was examined in a follow‐up survey. The survey had 3 goals: (1) to systematically and anonymously gather data about the ethical issues that employees struggle with in their daily work; (2) to raise the visibility of the hospital‐based ethics program and resources available to employees; and (3) to prioritize and focus the direction of the program's educational seminars, quality improvement projects, and ethics consultation.DesignOnline survey of employees.SettingUrban rehabilitation system of care.ParticipantsThe survey was open to all employees; 207 completed the survey.InterventionsN/AMain Outcome MeasurementsN/AConclusionsThree broad categories of moral distress were identified: institutional ethics, professional practice, and clinical decision‐making. Institutional ethics issues related to the health care environment, such as health care reimbursement pressures and corporate culture. Professional practice issues involved codes of behavior and concepts of professionalism, including patient confidentiality/privacy. Clinical decision‐making included such practical dilemmas as conflicts around goal‐setting, discharge planning, and assessment of decision‐making capacity. An anonymous survey of staff members allowed the hospital ethics program to identify sources of moral distress and prioritize strategies to address them.