bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of a molecular target for glutamate regulation of astrocyte water permeability
Authors: Gunnarson Eli , Zelenina Marina , Axehult Gustav , Song Yutong , Bondar Alexander , Krieger Patrik , Brismar Hjalmar , Zelenin Sergey , Aperia Anita 
Published: February 2008

AbstractAstrocytes play a key role for maintenance of brain water homeostasis, but little is known about mechanisms of short‐term regulation of astrocyte water permeability. Here, we report that glutamate increases astrocyte water permeability and that the molecular target for this effect is the aquaporin‐4 (AQP4) serine 111 residue, which is in a strategic position for control of the water channel gating. The glutamate effect involves activation of group I metabotropic glutamate receptors (mGluR), intracellular calcium release, and activation of calcium/calmodulin‐dependent protein kinase II (CaMKII) and nitric oxide synthase (NOS). The physiological impact of our results is underlined by the finding that mGluR activation increases the rate of hypoosmotic tissue swelling in acute rat hippocampal slices. Cerebral ischemia is associated with an excessive release of glutamate, and in postischemic cerebral edema ablation of AQP4 attenuates the degree of damage. Thus, we have identified AQP4 as the molecular target for drugs that may attenuate the development of brain edema. © 2008 Wiley‐Liss, Inc.
International dynamic risk sharing
Authors: Cavaliere Giuseppe , Fanelli Luca , Gardini Attilio 
Published: February 2008

AbstractIn this paper we examine the implications of international risk sharing among a set of countries in the presence of market frictions which complicate the instantaneous adjustment to the first‐order conditions. We suggest approximating the consumption streams of countries belonging to the risk sharing coalition in terms of a disequilibrium dynamic model embodying forward‐looking adjustment. Econometric methods for estimating and testing the model are discussed. Empirical analysis of a set of core European countries suggests that once preference parameters are allowed to vary across countries, we are able to identify a group of nations that share risks against idiosyncratic permanent income shocks. The equilibrium position, however, is reached after a long adjustment period. Copyright © 2008 John Wiley & Sons, Ltd.
Extreme US stock market fluctuations in the wake of 9/11
Authors: Straetmans S. T. M. , Verschoor W. F. C. , Wolff C. C. P. 
Published: February 2008

AbstractWe apply extreme value analysis to US sectoral stock indices in order to assess whether tail risk measures like value‐at‐risk and extremal linkages were significantly altered by 9/11. We test whether semi‐parametric quantile estimates of ‘downside risk’ and ‘upward potential’ have increased after 9/11. The same methodology allows one to estimate probabilities of joint booms and busts for pairs of sectoral indices or for a sectoral index and a market portfolio. The latter probabilities measure the sectoral response to macro shocks during periods of financial stress (so‐called ‘tail‐βs’). Taking 9/11 as the sample midpoint we find that tail‐βs often increase in a statistically and economically significant way. This might be due to perceived risk of new terrorist attacks. Copyright © 2008 John Wiley & Sons, Ltd.
Structural breaks and GARCH models of exchange rate volatility
Authors: Rapach David E. , Strauss Jack K. 
Published: February 2008

AbstractWe investigate the empirical relevance of structural breaks for GARCH models of exchange rate volatility using both in‐sample and out‐of‐sample tests. We find significant evidence of structural breaks in the unconditional variance of seven of eight US dollar exchange rate return series over the 1980–2005 period—implying unstable GARCH processes for these exchange rates—and GARCH(1,1) parameter estimates often vary substantially across the subsamples defined by the structural breaks. We also find that it almost always pays to allow for structural breaks when forecasting exchange rate return volatility in real time. Combining forecasts from different models that accommodate structural breaks in volatility in various ways appears to offer a reliable method for improving volatility forecast accuracy given the uncertainty surrounding the timing and size of the structural breaks. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and characterization of polymeric implant for kyphoplasty
Authors: Mizrahi Boaz , Shavit Ronen , Domb Abraham 
Published: February 2008

AbstractCopolymers of methyl methacrylate (MMA) and lauryl methacrylate (LMA) were prepared to obtain injectable ductile materials to be used in restoring vertebra height in kyphoplasty. Copolymers with Mw in the range of 130,000 and polydispersity of 1.8 were obtained. Several aspects of the effect of adding LMA monomers were examined including intrinsic viscosity, thermal properties, mechanical properties, and the ability to be injected under high pressure. By increasing the amount of LMA, the ductility of the polymer was increased, accompanied by a decrease in Young's modulus and strength. The copolymer with monomers ratio (MMA:LMA) 1:1 v/v possessed the most suitable mechanical properties and injectability, which may have potential clinical use in orthopedics. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Properties of an injectable low modulus PMMA bone cement for osteoporotic bone
Authors: Boger Andreas , Bohner Marc , Heini Paul , Verrier Sophie , Schneider Erich 
Published: February 2008

AbstractThe use of polymethylmethacrylate (PMMA) cement to reinforce fragile or broken vertebral bodies (vertebroplasty) leads to extensive bone stiffening. Fractures in the adjacent vertebrae may be the consequence of this procedure. PMMA with a reduced Young's modulus may be more suitable. The goal of this study was to produce and characterize stiffness adapted PMMA bone cements. Porous PMMA bone cements were produced by combining PMMA with various volume fractions of an aqueous sodium hyaluronate solution. Porosity, Young's modulus, yield strength, polymerization temperature, setting time, viscosity, injectability, and monomer release of those porous cements were investigated. Samples presented pores with diameters in the range of 25–260 μm and porosity up to 56%. Young's modulus and yield strength decreased from 930 to 50 MPa and from 39 to 1.3 MPa between 0 and 56% porosity, respectively. The polymerization temperature decreased from 68°C (0%, regular cement) to 41°C for cement having 30% aqueous fraction. Setting time decreased from 1020 s (0%, regular cement) to 720 s for the 30% composition. Viscosity of the 30% composition (145 Pa s) was higher than the ones received from regular cement and the 45% composition (100–125 Pa s). The monomer release was in the range of 4–10 mg/mL for all porosities; showing no higher release for the porous materials. The generation of pores using an aqueous gel seems to be a promising method to make the PMMA cement more compliant and lower its mechanical properties to values close to those of cancellous bone. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
The potential role of ribosomal protein S5 on cell cycle arrest and initiation of murine erythroleukemia cell differentiation
Authors: Matragkou Christina N. , Papachristou Eleni T. , Tezias Sotirios S. , Tsiftsoglou Asterios S. , Choli‐Papadopoulou Theodora , Vizirianakis Ioannis S. 
Published: February 2008

AbstractEvidence now exists to indicate that some ribosomal proteins besides being structural components of the ribosomal subunits are involved in the regulation of cell differentiation and apoptosis. As we have shown earlier, initiation of erythroid differentiation of murine erythroleukemia (MEL) cells is associated with transcriptional inactivation of genes encoding ribosomal RNAs and ribosomal proteins S5 (RPS5) and L35a. In this study, we extended these observations and investigated whether transfection of MEL cells with RPS5 cDNA affects the onset of initiation of erythroid maturation and their entrance in cell cycle arrest. Stably transfected MEL cloned cells (MEL‐C14 and MEL‐C56) were established and assessed for their capacity to produce RPS5 RNA transcript and its translated product. The impact of RPS5 cDNA transfection on the RPS5 gene expression patterns and the accumulation of RPS5 protein in inducible transfected MEL cells were correlated with their ability to: (a) initiate differentiation, (b) enter cell cycle arrest at G1/G0 phase, and (c) modulate the level of cyclin‐dependent kinases CDK2, CDK4, and CDK6. The data presented indicate that deregulation of RPS5 gene expression (constitutive expression) affects RPS5 protein level and delays both the onset of initiation of erythroid maturation and entrance in cell cycle arrest in inducer‐treated MEL cells. J. Cell. Biochem. 104: 1477–1490, 2008. © 2008 Wiley‐Liss, Inc.
Praxis and power
Authors: Partridge William L. 
Published: February 2008

AbstractThis article examines Prilleltensky's concept of psychopolitical validity in terms of its locus within the continuum of individual‐relational‐collective well‐being. It argues that the strength of Prilleltensky's position is its emphasis on the need for structural changes in power relationships rather than the imposition of ameliorative interventions. Political action, however, is necessary to advance human well‐being by reducing power inequities. To do so, it is argued requires action that is targeted, measured, and replicable. Empowerment though action alone can become lasting. For that reason, the concept of “praxis” and its implications for the design of empowerment initiatives need to be understood and incorporated within discussions of psychopolitical validity. © 2008 Wiley Periodicals, Inc.
Concentrated disadvantage in urban neighborhoods: psychopolitical validity as a framework for developing psychology‐related solutions
Authors: Nation Maury 
Published: February 2008

AbstractPsychology and community psychologists have been only peripherally involved in studying the sociopolitical factors including power differentials and resource inequities that are at the heart of the connection the between neighborhood conditions and individual well‐being. In this article, the author describes how the concept of psychopolitical validity provides community psychologists a framework for reconceptualizing the research on the effects of low‐income neighborhoods on well‐being. Specific elements of this framework include (a) analyzing the role of power in societal conceptions of social problems and targets of intervention, (b) posing research questions that illuminate the connection between individual and neighborhood well‐being, and (c) developing and implementing a range of techniques that both ameliorate an individual's symptoms and transform the neighborhood context. © 2008 Wiley Periodicals, Inc.
Transdisciplinary, multilevel action research to enhance ecological and psychopolitical validity
Authors: Christens Brian , Perkins Douglas D. 
Published: February 2008

AbstractThe authors explore the implications of recent proposals for a focus on power and social change in community psychology research and add needed contextual and methodological specificity. An expanded model of psychopolitical validity is presented that merges Isaac Prilleltensky's (this issue, pp. 116–136) domains, or stages of empowerment (oppression, liberation, wellness), with four ecological context domains (physical, sociocultural, economic, political) and greater clarity regarding levels of analysis. The physical–environmental context is used to illustrate some of the questions that may be generated by the expanded model. After discussing the role of democratic freedoms and institutions and the equitable distribution of decision‐making power in sustainable community development, the case is made for action research as a potent paradigm to move the field toward those goals. Multilevel and spatial analyses and transdisciplinary research (conceptually and/or methodologically integrative collaboration across multiple disciplines) are underutilized in Community Psychology. © 2008 Wiley Periodicals, Inc.
Confronting psychology's power
Authors: Fox Dennis 
Published: February 2008

AbstractIsaac Prilleltensky (this issue, pp. 116–136) seeks to make community psychology a more effective force for social justice. His discussion of psychopolitical validity raises a number of questions: How perfect must the theoretical framework be to usefully oppose unjust power? In what way is the notion of “psychopolitical validity” most useful? How might an analysis of power apply to community psychology's own institutions? Is redirecting community psychology the most effective way to bring about transformative social change, or is success more likely to come outside psychology? Might more research aimed at understanding the mechanisms of oppression and liberation help oppressors more than liberators? And how can critical psychologists move beyond critique to action? The proposed framework will help facilitate social change only if community psychology also changes itself. © 2008 Wiley Periodicals, Inc.
Power from the people? critical reflection on a conceptualization of power
Authors: Fryer David 
Published: February 2008

AbstractIsaac Prilleltensky's “The Role of Power in Wellness, Oppression, and Liberation: The Promise of Psychopolitical Validity” (2008) is commended as an interesting reading of the literature on power, which interestingly includes some and excludes other relevant writing. However, doubts are expressed as to whether the term “power,” as used in this article by Prilleltensky, is meaningful, necessary, useful, or advisable to community/critical psychology because it is fundamentally individualistic and psychologistic. Instead, it is proposed that power be understood as a dynamic of social systems rather than a property of individuals within them and that the apparent power of individuals is understood as the subjective manifestation of the societal distribution of power. Finally, it is suggested that Prilletensky's article itself functions in politically and ideologically conservative ways in relation to a number of problematically powerful interest groups. © 2008 Wiley Periodicals, Inc.
On power, psychopolitical validity, and play
Authors: Angelique Holly L. 
Published: February 2008

AbstractIn this commentary, the author discusses power as a useful concept for community psychology. Although Prilleltensky's analysis of power (this issue, pp. 116–136) has the potential to shift the ideological foundation of the field, the author notes that he focuses primarily on the ability to coerce and/or resist coercion. The author argues that other conceptions of power should be considered to promote wellness, resist oppression, and move toward liberation. The author discusses ways in which power is manifested and may be exposed. Specifically, the author offers a Foucauldian perspective on power relations and challenge individuals to examine the multiple ways that power is manifested in our own lives. © 2008 Wiley Periodicals, Inc.
Psychopolitical validity: power, culture, and wellness
Authors: Fisher Adrian T. , Sonn Christopher C. 
Published: February 2008

AbstractIn this commentary, the authors review and critique Prilleltensky's model of psychopolitical validity and wellness. Although the overt recognition of power, oppression, and political forces are viewed most favorably, cautions are also given. Of most importance is the way in which his model is based in an undeclared North American model of psychology and culture. The authors examine the disjuncture between the stated aims of psychopolitical validity and the ways in which different cultures and social systems construe the world. The proposal for a political focus on power and oppression is welcomed, but cautions are offered about the commensurability of different worldviews and practices. © 2008 Wiley Periodicals, Inc.
PU.1 and NFATc1 mediate osteoclastic induction of the mouse β3 integrin promoter
Authors: Crotti Tania N. , Sharma Sudarshana M. , Fleming Joseph D. , Flannery Merrilee R. , Ostrowski Michael C. , Goldring Steven R. , McHugh Kevin P. 
Published: February 2008

AbstractExpression of the αvβ3 integrin is required for normal osteoclast function. We previously showed that an evolutionary conserved NFATc1 binding site is required for RANKL induction and NFATc1 transactivation of the human β3 promoter. The mechanism conferring specificity for RANKL induction and NFATc1 transduction of the β3 gene in osteoclast differentiation is unclear since NFATc1 is expressed and activated in numerous cell types that do not express the β3 gene. PU.1 is an ETS family transcription factor in myeloid cells associated with expression of various osteoclast genes. The present study investigates the role of NFATc1 in concert with PU.1 in osteoclast‐specific transcription of the mouse β3 integrin gene. The mouse β3 promoter was transactivated by NFATc1 in RAW264.7 cells and deletion or mutation of either of the conserved NFAT and PU.1 binding sites abrogated transactivation. NFATc1 transactivation of the mouse β3 promoter was specifically dependent on co‐transfected PU.1 in HEK293 cells, to the exclusion of other ETS family members. Direct binding of NFATc1 and PU.1 to their cognate sequences was demonstrated by EMSA and NFATc1 and PU.1 occupy their cognate sites in RANKL‐treated mouse marrow precursors in chromatin immuno‐precipitation (ChIP) assays. TAT‐mediated transduction with dominant‐negative NFATc1 dose‐dependently blocked endogenous expression of the mouse β3 integrin and the formation of TRAP positive multinucleated cells in RANKL‐treated mouse macrophages. These data provide evidence that NFATc1, in concert with PU.1, are involved in regulation of β3 integrin expression during osteoclast differentiation and suggest that PU.1 confers specificity to the NFATc1 response to macrophage lineage cells. J. Cell. Physiol. 215: 636–644, 2008. © 2008 Wiley‐Liss, Inc.
NAADP‐induced Ca2+signaling in response to endothelin is via the receptor subtype B and requires the integrity of lipid rafts/caveolae
Authors: Gambara Guido , Billington Richard A. , Debidda Marcella , D'Alessio Alessio , Palombi Fioretta , Ziparo Elio , Genazzani Armando A. , Filippini Antonio 
Published: February 2008

AbstractWe have investigated the role of NAADP‐mediated Ca2+mobilization in endothelin (ET) signaling via endothelin receptor subtype A (ETA) and endothelin receptor subtype B (ETB) in rat peritubular smooth muscle cells. Microinjection and extracellular application of NAADP were both able to elicit Ca2+release which was blocked by inhibitory concentrations of NAADP, by impairing Ca2+uptake in acidic stores with bafilomycin, and by thapsigargin. Ca2+release in response to selective ETB stimulation was abolished by inhibition of NAADP signaling through the same strategies, while these treatments only partially impaired ETA‐dependent Ca2+signaling, showing that transduction of the ETB signal is dependent on NAADP. In addition, we show that lipid rafts/caveolae contain ETA, ETB, and NAADP/cADPR generating enzyme CD38 and that stimulation of ETB receptors results in increased CD38 activity; interestingly, ETB‐ (but not ETA‐) mediated Ca2+responses were antagonized by disruption of lipid rafts/caveolae with methyl‐β‐cyclodextrin. These data demonstrate a primary role of NAADP in ETB‐mediated Ca2+signaling and strongly suggest a novel role of lipid rafts/caveolae in triggering ET‐induced NAADP signaling. J. Cell. Physiol. 216: 396–404, 2008. © 2008 Wiley‐Liss, Inc.
Surface‐assisted laser desorption/ionization mass spectrometry (SALDI‐MS) of low molecular weight organic compounds and synthetic polymers using zinc oxide (ZnO) nanoparticles
Authors: Watanabe Takehiro , Kawasaki Hideya , Yonezawa Tetsu , Arakawa Ryuichi 
Published: February 2008

AbstractWe have developed surface‐assisted laser desorption/ionization mass spectrometry using zinc oxide (ZnO) nanoparticles with anisotropic shapes (ZnO‐SALDI‐MS). The mass spectra showed low background noises in the low m/z, i.e. less than 500 u region. Thus, we succeeded in SALDI ionization on low molecular weight organic compounds, such as verapamil hydrochloride, testosterone, and polypropylene glycol (PPG) (average molecular weight 400) without using a liquid matrix or buffers such as citric acids. In addition, we found that ZnO‐SALDI has advantages in post‐source decay (PSD) analysis and produced a simple mass spectrum for phospholipids. The ZnO‐SALDI spectra for synthetic polymers of polyethylene glycol (PEG), polystyrene (PS) and polymethylmethacrylate (PMMA) showed the sensitivity and molecular weight distribution to be comparable to matrix‐assisted laser desorption/ionization (MALDI) spectra with a 2,5‐dihydroxybenzoic acid (DHB) matrix. ZnO‐SALDI shows good performance for synthetic polymers as well as low molecular weight organic compounds. Copyright © 2008 John Wiley & Sons, Ltd.
The epineural sleeve technique for nerve graft reconstruction enhances nerve recovery
Authors: Lubiatowski Przemyslaw , Unsal Faik M. , Nair Dileep , Ozer Kagan , Siemionow Maria 
Published: February 2008

AbstractThe purpose of the study was evaluation of nerve recovery following epineural sleeve technique for graft reconstruction in rat sciatic nerve. This technique provides the epineural sleeve to cover and separate the site of coaptation. Animals were divided into three groups: CNG‐conventional nerve grafting, ESN‐epineural sleeve from recipient nerve stumps, ESG‐epineural sleeve from graft. Nerve regeneration was evaluated by pin‐prick, toe‐spread test, walking track analysis and somatosensory‐evoked potentials (SEP), gastrocnemius index (GI), and histomorphometric evaluation. Most parameters (SFI, SEPs, and GI) showed significantly better nerve recovery for ESN group when compared to conventional CNG group. Also ESG group revealed better result for SFI. Better functional results for ESN and ESG groups were further confirmed by histomorphometric analysis: higher axon density and diameters as well as thicker myelin sheath. Epineural sleeve graft technique may be promising method with potential application for nerve reconstructive procedures. Better functional nerve recovery can be anticipated. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
A new training method to improve deep microsurgical skills using a mannequin head
Authors: Takeuchi Mikinobu , Hayashi Nakamasa , Hamada Hideo , Matsumura Nobuhisa , Nishijo Hisao , Endo Shunro 
Published: February 2008

AbstractNeurosurgeons need fine and special microsurgical techniques, such as the ability to suture deep microvasculature. Intensive training is required to perform microsurgery, especially in deep microvascular anastomosis. There have been many previous reports of training methods for typical microsurgical techniques, including suturing of surgical gloves, Silastic tubes, living animals, and chicken wing arteries. However, there have been no reports of training methods to improve deep microsurgical skills under the various hand positions specific to neurosurgical operation. Here, we report a new training method using a mannequin head, water balloons, and clay to mimic actual deep microsurgery in the brain. This method allows trainees to experience microsurgery under various hand positions to approach the affected areas located at various depths in the brain from various angles. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Remark on the regularity for weak solutions to the magnetohydrodynamic equations
Authors: He Cheng , Wang Yun 
Published: February 2008

AbstractWe study the regularity criteria for weak solutions to the incompressible magnetohydrodynamic (MHD) equations. Some regularity criteria, which are related only with u+B or u−B, are obtained for weak solutions to the MHD equations. Copyright © 2008 John Wiley & Sons, Ltd.