bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheses, Properties and Structures of [{(C5Me5)2Nb}2NiTe4] and [(tBuC5H4Nb)2Ni5Te7(Ph2PCH2PPh2)2]: The Quest for Tetratelluronickelate Clusters
Authors: Brandl Martin , Ebner Alexander , Kubicki Marek M. , Mugnier Yves , Wachter Joachim , Vigier‐Juteau Estelle , Zabel Manfred
Published: January 2007

The reaction of [Ni(COD)2] with [Cp*2NbTe2H] (1; Cp* = η‐C5Me5) in the presence of Ph2PCH2PPh2(dppm) in boiling toluene gives black‐violet [(Cp*2Nb)2NiTe4] (3). If [Cp′2NbTe2H] (2; Cp′ =tBuC5H4) is used under similar conditions dark‐brown [(Cp′Nb)2Ni5Te7(dppm)2] (4) is formed. The structures of3and4have been determined crystallographically. Complex3contains a severely distorted NiTe4tetrahedron to which two niobocene groups are coordinated. Density functional analysis of the electronic structure of the NiTe4building block shows that it is best described as an [Ni(η2‐Te2)2]2–fragment. The structure of4reveals the presence of two Ni5and Te5tetragonal pyramids stacked into each other in an opposite way. Six of the Te bridges form two triangular faces, each of which is capped by a Cp′Nb fragment. Additionally, two dppm ligands bridge the long Ni–Ni edges of the Ni4bases. Oxidation of3with [(C5H5)2Fe]BPh4gives paramagnetic [(Cp*2Nb)2NiTe4]BPh4(6), whereas oxidation with [(C5H5)2Fe]PF6proceeds with fluoride transfer to give [Cp*2NbF2]PF6(5). Electrochemical studies of3reveal the existence of the redox couples [3]2+/[3]+/[3]0/[3]–/[3]2–. Density functional calculations carried out on the different oxidation states of3reveal the following main features: the persistent presence of Nb–Ni bonds and the retention of Te–Te bonds in cationic and neutral species and their breaking off in reduced forms. Irrespective of the initial site of electrochemical attack, the Te atoms and Cp rings are principally affected in the final products.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Zinc Thiolate Complexes [ZnLn(SR)]+ with Azamacrocyclic Ligands, Part III: The Influence of the Ligand Ln on the Reactivity of Zinc‐Bound Thiolate
Authors: Notni Johannes , Günther Wolfgang , Anders Ernst
Published: January 2007

In this study, we focus on the structure–reactivity relationship of cationic zinc thiolate complexes with the general formula [Zn(Ln)(SR)]ClO4 (Ln: n‐dentate azamacrocyclic ligand; R = phenylmethyl). The complexes feature macrocyclic ligands with ring sizes varying from 11 to 16 atoms and possess three or four nitrogen donors (three of them containing one tertiary nitrogen). Thiol methylations with methyl iodide have been performed in order to determine the relative reactivities, because this reaction has been used before to investigate zinc thiolate reactivity and therefore allows comparison of our results with literature data. The kinetic behaviour was investigated in nitromethane and dichloromethane and was found to be second order in all cases. The observed rate constants vary in the range of k2 = 2.46–55.28×10–3 M–1 s–1 in nitromethane and k2 = 0.23–7.35×10–3 M–1 s–1 in dichloromethane at 300 K. Furthermore, the structures of all thiolate complexes were optimised at the B3LYP/6‐311+G(d) level of theory. Natural bond orbital (NBO) analyses were performed to obtain information on partial charges of the heteroatoms and energies of a lone pair in a p‐type orbital at the zinc‐bound sulfur. In order to elucidate which parameters determine reactivity, selected structural and electronic parameters were correlated with the experimental rate constants. As a result, we found that the reaction is controlled predominantly by frontier orbital energy in dichloromethane and by charge in nitromethane. However, we observed that electronic reactivity control can be overridden by the degree of steric obstruction of the zinc ion, which directly depends on ring size and configuration of the ring nitrogens. The complex [Zn(cyclen)(SR)]ClO4 (5) can therefore not be included in any of the correlations; steric constraint imposed by the comparably small ring system causes an extraordinarily increased reactivity. In turn, this finding provides a new rationale for the high reactivity reported for the cyclen complex [Zn(cyclen)(OH)]+, which has been used as a model for carbonic anhydrase in previous studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Electrogenerated Chemiluminescence Ethanol Biosensor Based on Carbon Nanotube‐Titania‐Nafion Composite Film
Authors: Choi Han Nim , Yoon Sook Hyun , Lyu Young‐Ku , Lee Won‐Yong
Published: January 2007

Mesoporous titania‐Nafion composite doped with carbon nanotube (CNT) has been used for the immobilization of tris(2,2′‐bipyridyl)ruthenium(II) (Ru(bpy)32+) and alcohol dehydrogenase on an electrode surface to yield a highly sensitive and stable electrogenerated chemiluminescence (ECL) ethanol biosensor. The presence of CNT in the composite film increases not only the sensitivity of the ECL biosensor but also the long‐term stability of the biosensor. The present biosensor responds linearly to ethanol in the wide concentration ranges from 1.0×10−5 M to 1.0×10−1 M with a detection limit of 5.0×10−6 M (S/N=3). The present ECL ethanol biosensor exhibited higher ECL response compared to that obtained with the ECL biosensor based on the corresponding composite without CNT. The present CNT‐based ECL biosensor showed good long‐term stability with 75% of its initial activity retained after 2 weeks of storage in 50 mM phosphate buffer at pH 7.0.
In Situ Amperometric Detection of Vesicles and Microgel Phases in an Aggregating System: Calcium Alginate
Authors: DeNardis Nadica Ivošević , Žutić Vera , Svetličić Vesna , Urbani Ranieri
Published: January 2007

In situ amperometric characterization of an aggregating system in terms of molecular adsorption and single microparticle interactions at the electrode interface is demonstrated using a model system: alginate/Ca(II) in an aqueous electrolyte solution. Recording of chronoamperometric curves of oxygen reduction at the dropping mercury electrode is designed for detection of dip‐shaped signals of individual gel microparticles. By addition of Ca(II) decrease of alginate adsorption is accompanied by appearance of signals indicating vesicle type association of alginate molecules and microparticles of gel phase. AFM imaging provided evidence of initial stage in calcium alginate gel formation.
Electrocatalysis and Voltammetric Determination of Dopamine at a Calix[4]arene Crown‐4 Ether Modified Glassy Carbon Electrode
Authors: Lai Guo‐Song , Zhang Hai‐Li , Jin Chuan‐Ming
Published: January 2007

A sensitive and selective electrochemical method for the determination of dopamine (DA) was developed using a calix[4]arene crown‐4 ether (CACE) film modified glassy carbon electrode (GCE).The modified electrode exhibited good electrocatalytic activity for electrochemical oxidation of DA in the pH 6.00 Britton–Robinson buffer solution, and ascorbic acid (AA) did not interfere with it. The diffusion coefficient (D=2.7×10−5 cm2 s−1), and the kinetic parameter such as the electron transfer coefficient (α=0.54) of DA at the surface of CACE were determined using electrochemical approaches. The catalytic oxidation peak currents showed a linear dependence on the DA concentration and a linear analytical curve was obtained in the range of 2.0×10−5–1.0×10−3 M of DA with a correlation coefficient of 0.9990. The detection limit (S/N=3) was estimated to be 3.4×10−6 M. This method was also examined for the determination of DA in an injection sample. In addition, effects of possible interferences were investigated. The present work shows the potential of the proposed method for the fabrication of a modified electrode, as it can be effectively used for voltammetric detection of DA.
The stability of AGC systems with commensurate delays
Authors: Liu Meizhao , Yang Li , Gan Deqiang , Wang Dexin , Gao Fuying , Chen Yan
Published: January 2007

With communication signal delays, a power system control can actually excite sustained oscillations. This paper proposes a method to analyze the stability of such delayed systems and the like. The stability is estimated using delay margins. The main result is nicely based on a sufficient and necessary condition. Simulation results of the Automatic Generation Control (AGC) system of the real‐world East China Power Grid (ECPG) system are reported to validate the methodology. Copyright © 2007 John Wiley & Sons, Ltd.
A proposed modification to the dynamic approach
Authors: Bhushan S.
Published: January 2007

In this paper a modification related to the scale‐invariancy condition, based on a simple dissipation argument coupled with the hypothesis of Chen et al. (J. Fluids Eng. 2005; 127:840–850), is proposed for the dynamic model coefficient evaluation approach. The modification is applied to the Smagorinsky model and used in the calculations of low Reynolds number (Reτ = 180) channel flow, where the scale‐invariancy assumption of the dynamic approach is expected to fail along the wall‐normal direction. A detailed analysis of the results is performed for the mean velocity profile, dissipation characteristics, second and higher order statistics, and the energy spectra. The results are compared with the Smagorinsky, the dynamic Smagorinsky, no model, the modification proposed by Meneveau and Lund (Phys. Fluids 1996; 9(12):3932–3934), and the DNS data. The proposed modification yields a better model coefficient profile and shows definitive improvement of the results for all flow statistics considered. Copyright © 2007 John Wiley & Sons, Ltd.
Stability of fluid–structure thermal simulations on moving grids
Authors: Roe B. , Haselbacher A. , Geubelle P. H.
Published: January 2007

This article analyses the stability of a thermally coupled fluid–structure interaction problem with a moving interface. Two types of fluid and structural discretizations are investigated: finite‐difference/finite‐difference as well as the more traditional finite‐volume/finite‐element (FV/FE) configuration. In either case, the material properties and grid spacing are treated as uniform within each domain. A theoretical stability analysis and corresponding numerical tests show that greater stability is associated with the algorithm in which the fluid domain is passed a Dirichlet condition and the solid domain a von Neumann condition and that the stability of the coupled scheme may be strongly affected by the interface velocity. Furthermore, it shows that the interface velocity has a larger destabilizing effect on the FV/FE discretization than on a finite‐difference/finite‐difference discretization. Copyright © 2007 John Wiley & Sons, Ltd.
The influence of source terms on stability, accuracy and conservation in two‐dimensional shallow flow simulation using triangular finite volumes
Authors: Murillo J. , García‐Navarro P. , Burguete J. , Brufau P.
Published: January 2007

The two‐dimensional shallow water model is a hyperbolic system of equations considered well suited to simulate unsteady phenomena related to some surface wave propagation. The development of numerical schemes to correctly solve that system of equations finds naturally an initial step in two‐dimensional scalar equation, homogeneous or with source terms. We shall first provide a complete formulation of the second‐order finite volume scheme for this equation, paying special attention to the reduction of the method to first order as a particular case.

The explicit first and second order in space upwind finite volume schemes are analysed to provide an understanding of the stability constraints, making emphasis in the numerical conservation and in the preservation of the positivity property of the solution when necessary in the presence of source terms. The time step requirements for stability are defined at the cell edges, related with the traditional Courant–Friedrichs–Lewy (CFL) condition. Copyright © 2007 John Wiley & Sons, Ltd.
Application of second‐order adjoint technique for conduit flow problem
Authors: Kurahashi T. , Kawahara M.
Published: January 2007

This paper presents the way to obtain the Newton gradient by using a traction given by the perturbation for the Lagrange multiplier. Conventionally, the second‐order adjoint model using the Hessian/vector products expressed by the product of the Hessian matrix and the perturbation of the design variables has been researched (Comput. Optim. Appl. 1995; 4:241–262). However, in case that the boundary value would like to be obtained, this model cannot be applied directly. Therefore, the conventional second‐order adjoint technique is extended to the boundary value determination problem and the second‐order adjoint technique is applied to the conduit flow problem in this paper. As the minimization technique, the Newton‐based method is employed. The Broyden–Fletcher–Goldfarb–Shanno (BFGS) method is applied to calculate the Hessian matrix which is used in the Newton‐based method and a traction given by the perturbation for the Lagrange multiplier is used in the BFGS method. Copyright © 2007 John Wiley & Sons, Ltd.
Some recent numerical advances for two‐phase flow modelling in NEPTUNE project
Authors: Hérard J. M. , Hurisse O.
Published: January 2007

This paper is devoted to a brief review of some problems arising in the NEPTUNE project, whose main objective consists in preparing a new generation of two‐phase flow codes covering the whole range of modelling scales for nuclear power plants. Focus is given on multi‐phase flow modelling and on the unsteady coupling of existing codes. Some recent results are displayed and a few open problems are discussed in the manuscript. A draft version of this paper has been presented as an invited lecture during the FVCA4 meeting. Copyright © 2007 John Wiley & Sons, Ltd.
Fingering patterns on an expanding miscible drop in a rotating Hele‐Shaw cell
Authors: Chen Chen‐Hua , Chen Ching‐Yao
Published: January 2007

We perform a detailed numerical study for the evolution of an expanding miscible drop in a rotating Hele‐Shaw cell. Two mathematical formulations applied to model the coating layer expansion during practical spin‐coating process, such as thinning of the layer by cell pressing and drop spreading outward due to injection, are investigated. Including miscible interfacial stresses, we focus on the investigation of dynamical and morphological influences of two different stabilizing parameters: the gap width parameter for the pressing cell and the injecting strength. In the case of a pressing cell, the fingering features of the expanding miscible drop, such as the critical radius, are distinct from those ones in the experiments of spin coating due to the different distributions of the inherent radial velocity. On the other hand, the global interfacial evolutions of an expanding drop with an additional injection bear remarkable resemblances to their immiscible counterparts. The better agreement for an injecting model suggests its appropriateness when we simulate the emerging fingering instabilities in the spin‐coating process. Moreover, we investigate the effects of Coriolis force at higher miscible Bond numbers. Coriolis force affects significantly the onset of fingering instability and the tilting angles of fingers. These stable effects are in line with the results from the previous studies for miscible and immiscible flow fields. Copyright © 2007 John Wiley & Sons, Ltd.
Time use and costs of institutionalised elderly persons with or without dementia: results from the Nordanstig cohort in the Kungsholmen Project—a population based study in Sweden
Authors: Nordberg Gunilla , Wimo Anders , Jönsson Linus , Kåreholt Ingemar , Sjölund Britt‐Marie , Lagergren Mårten , von Strauss Eva
Published: January 2007

Background

The aging of the population has become a worldwide phenomenon. This leads to increased demand for services and with limited resources it is important to find a way to estimate how resources can be match to those with greatest need.

Aims

To analyse time use and costs in institutional care in relation to different levels of cognitive and functional capacity for elderly persons.

Methods

The population consisted of all institutionalised inhabitants, 75 + years, living in a rural community (n = 176). They were clinically examined by physicians and interviewed by nurses. Staff and informal care‐giving time was examined with the RUD (Resource Utilization in Dementia) instrument.

Results

Tobit regression analyses showed that having dementia increased the amount of ADL care time with 0.9 h when compared to those not having dementia, whereas each loss of an ADL function (0–6) added 0.6 h of ADL care time. Analysing the total care time use, the presence of dementia added more than 9 h, while each loss of one ADL function added 2.9 h. There were some informal care contributions, however with no correlation to severity in dependency. The estimated cost for institutional care increased with more than 85% for people being dependent in 5–6 ADL activities compared to persons with no functional dependency, and with 30% for persons with dementia compared to the non‐demented.

Conclusion

There is a variation in time use in institutional settings due to differences in ADL dependency but also whether dementia is present or not. This variation has implications for costs of institutional care. Copyright © 2007 John Wiley & Sons, Ltd.
Chitosan prevents the development of AOM‐induced aberrant crypt foci in mice and suppressed the proliferation of AGS cells by inhibiting DNA synthesis
Authors: Lin Shyr‐Yi , Chan Hing‐Yuen , Shen Fung‐Hsiu , Chen Mei‐Huei , Wang Ying‐Jan , Yu Chung‐Keung
Published: January 2007

We study the effect of fungal‐derived chitosan on the development of chemical‐induced colonic precancerous lesions in ICR mice and delineate its possible molecular mechanisms. In the 2 weeks preventive experiments, mice fed with a diet containing high molecular weight chitosan (HMWC) had significant fewer aberrant crypt foci formation than those fed with control diet. As the treatment extended to 6 weeks, both low molecular weight chitosan (LMWC)‐ and HMWC‐fed mice contained less aberrant crypt foci when compared to control. However, such effect was not observed in mice in the 6 weeks therapeutic experiments. The anti‐tumorigenesis effect of water‐soluble chitosan oligomer (WSCO) was tested on four cancer cell lines. WSCO significantly suppressed AGS and to a less extent, COLO 205 cells proliferation. Flow cytometry analysis of cell cycle distribution indicated that the percentage of S phase reduced significantly in AGS cells treated with WSCO together with a decrease in DNA synthesis rate in BrdU incorporation assay. WSCO treatment also upregulated cell cycle‐related genes p21/Cip and p27/Kip, whereas downregulated that of PCNA. J. Cell. Biochem. 100: 1573–1580, 2007. © 2007 Wiley‐Liss, Inc.
Decorin synthesized by arterial smooth muscle cells is retained in fibrin gels and modulates fibrin contraction
Authors: Johnson Pamela Y. , Potter‐Perigo Susan , Gooden Michel D. , Vernon Robert B. , Wight Thomas N.
Published: January 2007

Fibrin serves as a provisional extracellular matrix (ECM) for arterial smooth muscle cells (ASMC) after vascular injury, yet little is known about the effect of fibrin on ECM remodeling by these cells. To address this question, monkey ASMC were grown on fibrin gels and tissue culture (TC) plastic, and proteoglycan synthesis and accumulation were assessed by radiolabeling. Initial rates of 35S‐sulfate incorporation into proteoglycans were identical for both groups, but increased proteoglycan accumulation was observed in cultures grown for 48 h on fibrin. This increased accumulation on fibrin was due to reduced proteoglycan turnover and retention within the fibrin gel. Decorin and biglycan constituted 40 and 14% of the total proteoglycan in the fibrin gels, whereas their combined contribution was only 12% in control matrices. To explore whether the retention of decorin in fibrin had any influence on the properties of the fibrin gel, ASMC‐mediated fibrin contraction assays were performed. Both de novo synthesis of decorin as well as decorin added during polymerization inhibited the ability of the cells to contract fibrin. In contrast, decorin added exogenously to mature fibrin matrices had no effect on fibrin gel contraction. This study illustrates that decorin derived from ASMC selectively accumulates in fibrin and modifies fibrin architecture and mechanical properties. Such an accumulation may influence wound healing and the thrombotic properties of this provisional pro‐atherosclerotic ECM. J. Cell. Biochem. 101: 281–294, 2007. © 2007 Wiley‐Liss, Inc.
CCK1 and 2 receptors are expressed in immortalized rat brain neuroblasts: Intracellular signals after cholecystokinin stimulation
Authors: Langmesser Sonja , Cerezo‐Guisado Maria I. , Lorenzo Maria J. , Garcia‐Marin Luis J. , Bragado Maria J.
Published: January 2007

Cholecystokinin (CCK) is one of the most abundant neuropeptides in the central nervous system (CNS) where it promotes important functions by activation of receptors CCK1 and CCK2. Our aim was to investigate CCK receptors expression and their downstream intracellular signaling in immortalized rat brain neuroblasts. Results show that CCK1 and CCK2 receptor mRNAs and CCK2 receptor protein are expressed in neuroblasts. CCK incubation of neuroblasts leads to stimulation in a time‐dependent manner of several signaling pathways, such as tyrosine phosphorylation of adaptor proteins paxillin and p130Cas, phosphorylation of p44/p42 ERKs as well as PKB (Ser473). Moreover, CCK‐8 stimulates the DNA‐binding activity of the transcription factor AP‐1. The CCK2 receptor agonist gastrin stimulates ERK1/2 phosphorylation in a comparable degree as CCK does. ERK1/2 phosphorylation activated by CCK‐8 was markedly inhibited by the CCK2 receptor antagonist CR2945. Incubation for 48 h with CCK‐8 increases neuroblasts viability in a similar degree as EGF. In summary, our data clearly identify CCK1 and CCK2 receptor mRNAs and CCK2 receptor protein in brain neuroblasts and show that incubation with CCK promotes cell proliferation and activates the phosphorylation of survival transduction pathways. Stimulation of ERK1/2 phosphorylation by CCK is mainly mediated by the CCK2 receptor. Moreover, this work might provide a novel model of proliferating neuronal cells to further study the biochemical mechanisms by which the neuropeptide CCK exerts its actions in the CNS. J. Cell. Biochem. 100: 851–864, 2007. © 2007 Wiley‐Liss, Inc.
Identification and predominant expression of annexin A2 in epithelial‐type cells of the rice field eel
Authors: Shang Xuan , Sun Jinhua , He Yan , Zhao Wei , Li Qin , Zhou Fang , Chen Bo , Cheng Hanhua , Zhou Rongjia
Published: January 2007

Annexin is the largest family of genes encoding eukaryotic calcium‐binding proteins that do not contain the EF hand motif. Annexin A2 has a common annexin core domain, consisting of four so‐called annexin repeats, and each of these repeats has about 70 amino acids in length. Here we report identification of annexin A2 from rice field eel by degenerate PCR and RACE techniques. Three‐dimensional structure prediction shows that it has similar annexin repeat architecture. Phylogenetic analysis shows that this gene fits with the annexin A2 clade of vertebrates. Subcellular co‐localization and co‐immunoprecipitation indicated annexin A2 interacted with its ligand S100A10, confirming characteristics of the rice field eel annexin A2. RT‐PCR and Western blot results indicate annexin A2 expressed ubiquitously in adult tissues. Immunofluorescence analysis shows obvious immunoreactivity in the nuclear membrane of developing oocytes and base membrane of mature oocytes in ovary and ovotestis. After the gonad differentiates into testis, annexin A2 protein expressed in the site of seminal vesicles epithelium in testis. The results provided a clue to the potential role of annexin A2 in the gonadal differentiation from ovary, via ovotestis to testis of the rice field eel. J. Cell. Biochem. 101: 600–608, 2007. © 2007 Wiley‐Liss, Inc.
Periostin regulates collagen fibrillogenesis and the biomechanical properties of connective tissues
Authors: Norris Russell A. , Damon Brook , Mironov Vladimir , Kasyanov Vladimir , Ramamurthi Anand , Moreno‐Rodriguez Ricardo , Trusk Thomas , Potts Jay D. , Goodwin Richard L. , Davis Jeff , Hoffman Stanley , Wen Xuejun , Sugi Yukiko , Kern Christine B. , Mjaatvedt Corey H. , Turner Debi K. , Oka Toru , Conway Simon J. , Molkentin Jeffery D. , Forgacs Gabor , Markwald Roger R.
Published: January 2007

Periostin is predominantly expressed in collagen‐rich fibrous connective tissues that are subjected to constant mechanical stresses including: heart valves, tendons, perichondrium, cornea, and the periodontal ligament (PDL). Based on these data we hypothesize that periostin can regulate collagen I fibrillogenesis and thereby affect the biomechanical properties of connective tissues. Immunoprecipitation and immunogold transmission electron microscopy experiments demonstrate that periostin is capable of directly interacting with collagen I. To analyze the potential role of periostin in collagen I fibrillogenesis, gene targeted mice were generated. Transmission electron microscopy and morphometric analyses demonstrated reduced collagen fibril diameters in skin dermis of periostin knockout mice, an indication of aberrant collagen I fibrillogenesis. In addition, differential scanning calorimetry (DSC) demonstrated a lower collagen denaturing temperature in periostin knockout mice, reflecting a reduced level of collagen cross‐linking. Functional biomechanical properties of periostin null skin specimens and atrioventricular (AV) valve explant experiments provided direct evidence of the role that periostin plays in regulating the viscoelastic properties of connective tissues. Collectively, these data demonstrate for the first time that periostin can regulate collagen I fibrillogenesis and thereby serves as an important mediator of the biomechanical properties of fibrous connective tissues. J. Cell. Biochem. 101: 695–711, 2007. © 2007 Wiley‐Liss, Inc.
Fractionated and acute irradiation induced signaling in a murine tumor
Authors: Mitra Anirban Kumar , Krishna Malini
Published: January 2007

The effect of fractionated doses of Co60 γ‐irradiation (2 Gy per fraction over 5 days), as is delivered in cancer radiotherapy, was compared with acute doses of 10 and 2 Gy, in a serially transplanted mouse fibrosarcoma grown in Swiss mice. The aspects that were studied included the three major mitogen‐activated protein (MAP) kinases, namely p44 MAP kinase, p38 MAP kinase, and stress‐activated protein (SAP) kinase, which are known to be involved in determining the cell fate following exposure to ionizing radiation. The response of dual specificity phosphatase PAC1 which is involved in the dephosphorylation of MAP kinases was also looked at. There were significant differences in the response to different dose regimens for all the factors studied. Fractionated irradiation elicited an adaptive response with a sustained activation over 7 days of prosurvival p44 MAP kinase which was balanced by the increased activation of proapoptotic p54 SAP kinase up to 1 day post‐irradiation, whereas, phosphorylated p38 MAP kinase showed a decrease at most time points. PAC1 was induced following fractionated irradiation and may be acting as a feed back regulator of p44 MAP kinase. The activation of SAP kinase after fractionated irradiation may be a stress response, whereas, constitutively activated p44 MAP kinase may play an important role in the induction of radioresistance during fractionated radiotherapy of cancer and may serve as a promising target for specific inhibitors to enhance the efficacy of radiotherapy. J. Cell. Biochem. 101: 745–752, 2007. © 2007 Wiley‐Liss, Inc.
Interleukin‐1β selectively decreases the synthesis of versican by arterial smooth muscle cells
Authors: Lemire Joan M. , Chan Christina K. , Bressler Steven , Miller John , LeBaron Richard G. , Wight Thomas N.
Published: January 2007

Proteoglycans accumulate in lesions of atherosclerosis but little is known as to which factors regulate the synthesis of these molecules. Interleukin‐1β (IL‐1β) is a cytokine involved in vascular lesion development but it is not clear whether it has specific effects on proteoglycan synthesis by arterial smooth muscle cells (ASMC). Monkey ASMC were treated with IL‐1β and proteoglycan synthesis assessed using [35S]‐sulfate and [35S]‐Trans amino acid labeling. Four prominent size populations of proteoglycans, as determined by SDS–PAGE gradient gel electrophoresis, were observed in the culture medium and identified as versican, biglycan, decorin, and an unknown population that migrated to the gel interface. IL‐1β treatment decreased significantly the synthesis of versican, while increasing the synthesis of decorin, but having no effect on biglycan synthesis. Northern blot analyses confirmed this selective effect on versican and decorin mRNA transcripts. Nuclear run‐on and RNA inhibition studies showed that decreased mRNA for versican was due to increased mRNA degradation and not to changes in transcription. In addition, IL‐1β increased the synthesis of the population of proteoglycans that separated at the SDS–PAGE gel interface. Chondroitinase ABC lyase digestion of this population revealed a complex of proteins composed of versican (350 kDa), an unidentified protein (215 kDa), and a 23 kDa protein identified by sequence analyses as serglycin. These data demonstrate that IL‐1β selectively downregulates versican synthesis by ASMC, while positively regulating the synthesis of other proteoglycans. J. Cell. Biochem. 101: 753–766, 2007. © 2007 Wiley‐Liss, Inc.
NF‐κB pathway is involved in griseofulvin‐induced G2/M arrest and apoptosis in HL‐60 cells
Authors: Uen Yih‐Huei , Liu Der‐Zen , Weng Meng‐Shih , Ho Yuan‐Soon , Lin Shyr‐Yi
Published: January 2007

Griseofulvin (GF), an oral antifungal agent, has been shown to exert antitumorigenesis effect through G2/M cell cycle arrest in colon cancer cells. But the underlying mechanisms remained obscure. The purpose of this study is to test the cytotoxic effect of GF on HL‐60 and HT‐29 cells and elucidate its underlying molecular pathways. Dose‐dependent and time‐course studies by flow cytometry demonstrated that 30 to 60 µM GF significantly induced G2/M arrest and to a less extend, apoptosis, in HL‐60 cells. In contrast, only G2/M arrest was observed in HT‐29 cells under similar condition. Pretreatment of 30 µM TPCK, a serine protease inhibitor, completely reversed GF‐induced G2/M cell cycle arrest and apoptosis in HL‐60 cells but not in HT‐29 cells. The GF‐induced G2/M arrest in HL‐60 cells is reversible. Using EMSA and super‐shift analysis, we demonstrated that GF stimulated NF‐κB binding activity in HL‐60 cells, which was completely inhibited by pretreatment of TPCK. Treatment of HL‐60 with 30 µM GF activated JNK but not ERK or p38 MAPK and subsequently resulted in phosporylation of Bcl‐2. Pretreatment of TPCK to HL‐60 cells blocked the GF‐induced Bcl‐2 phosphorylation but not JNK activation. Time course study demonstrated that activation of cdc‐2 kinase activity by GF correlated with Bcl‐2 phosphorylation. Taken together, our results suggest that activation of NF‐κB pathway with cdc‐2 activation and phosphorylation of Bcl‐2 might be involved in G2/M cell cycle arrest in HL‐60 cells. J. Cell. Biochem. 101:1165–1175, 2007. © 2007 Wiley‐Liss, Inc.
Generation of insulin‐producing cells from PDX‐1 gene‐modified human mesenchymal stem cells
Authors: Li Yanhua , Zhang Rui , Qiao Haifa , Zhang Heping , Wang Yunfang , Yuan Hongfeng , Liu Qinbin , Liu Daqing , Chen Lin , Pei Xuetao
Published: January 2007

Islet cell replacement is considered as the optimal treatment for type I diabetes. However, the availability of human pancreatic islets for transplantation is limited. Here, we show that human bone marrow‐derived mesenchymal stem cells (hMSCs) could be induced to differentiate into functional insulin‐producing cells by introduction of the pancreatic duodenal homeobox‐1 (PDX‐1). Recombinant adenoviral vector was used to deliver PDX‐1 gene into hMSCs. After being infected with Ad‐PDX‐1, hMSCs were successfully induced to differentiate into insulin‐secreting cells. The differentiated PDX‐1+ hMSCs expressed multiple islet‐cell genes including neurogenin3 (Ngn3), insulin, GK, Glut2, and glucagon, produced and released insulin/C‐peptide in a weak glucose‐regulated manner. After the differentiated PDX‐1+ hMSCs were transplanted into STZ‐induced diabetic mice, euglycemia can be obtained within 2 weeks and maintained for at least 42 days. These findings validate the hMSCs model system as a potential basis for enrichment of human beta cells or their precursors, and a possible source for cell replacement therapy in diabetes. J. Cell. Physiol. 211: 36–44, 2007. © 2007 Wiley‐Liss, Inc.
ß‐adrenergic receptor agonists delay while antagonists accelerate epithelial wound healing: Evidence of an endogenous adrenergic network within the corneal epithelium
Authors: Pullar Christine E. , Zhao Min , Song Bing , Pu Jin , Reid Brian , Ghoghawala Shahed , McCaig Colin , Isseroff R. Rivkah
Published: January 2007

Wound healing is a complex and well‐orchestrated biological process. Corneal epithelial cells (CECs) must respond quickly to trauma to rapidly restore barrier function and protect the eye from noxious agents. They express a high level of ß2‐adrenergic receptors but their function is unknown. Here, we report the novel finding that they form part of a regulatory network in the corneal epithelium, capable of modulating corneal epithelial wound repair. ß‐adrenergic receptor agonists delay CEC migration via a protein phosphatase 2A‐mediated mechanism and decrease both electric field‐directed migration and corneal wound healing. Conversely, ß‐adrenergic receptor antagonists accelerate CEC migration, enhance electric field‐mediated directional migration, and promote corneal wound repair. We demonstrate that CECs express key enzymes required for epinephrine (ß‐adrenergic receptor agonist) synthesis in the cytoplasm and can detect epinephrine in cell extracts. We propose that the mechanism for the pro‐motogenic effect of the ß‐adrenergic antagonist is blockade of the ß2‐adrenergic receptor preventing autocrine catecholamine binding. Further investigation of this network will improve our understanding of one of the most frequently prescribed class of drugs. J. Cell. Physiol. 211: 261–272, 2007. © 2007 Wiley‐Liss, Inc.
From the laboratory bench to the patient's bedside: An update on clinical trials with mesenchymal stem cells
Authors: Giordano Antonio , Galderisi Umberto , Marino Ignazio R.
Published: January 2007

Mesenchymal Stem Cells (MSCs) are non‐hematopoietic multi‐potent stem‐like cells that are capable of differentiating into both mesenchymal and non‐mesenchymal lineages. In fact, in addition to bone, cartilage, fat, and myoblasts, it has been demonstrated that MSCs are capable of differentiating into neurons and astrocytes in vitro and in vivo. MSCs are of interest because they are isolated from a small aspirate of bone marrow and can be easily expanded in vitro. As such, these cells are currently being tested for their potential use in cell and gene therapy for a number of human diseases. Nevertheless, there are still some open questions about origin, multipotentiality, and anatomical localization of MSCs. In this review, we discuss clinical trials based on the use of MSCs in cardiovascular diseases, such as treatment of acute myocardial infarction, endstage ischemic heart disease, or prevention of vascular restenosis through stem cell‐mediated injury repair. We analyze data from clinical trials for treatment of osteogenesis imperfecta (OI), which is a genetic disease characterized by production of defective type I collagen. We describe progress for neurological disease treatment with MSC transplants. We discuss data on amyotrophic lateral sclerosis (ALS) and on lysosomal storage diseases (Hurler syndrome and metachromatic leukodystrophy). A section of review is dedicated to ongoing clinical trials, involving MSCs in treatment of steroid refractory Graft Versus Host Disease (GVHD); periodontitis, which is a chronic disease affecting periodontium and causing destruction of attachment apparatus, heart failure, and bone fractures. Finally, we will provide information about biotech companies developing MSC therapy. J. Cell. Physiol. 211: 27–35, 2007. © 2007 Wiley‐Liss, Inc.
Injury of skeletal muscle and specific cytokines induce the expression of gap junction channels in mouse dendritic cells
Authors: Corvalán Liliana A. , Araya Roberto , Brañes María C. , Sáez Pablo J. , Kalergis Alexis M. , Tobar Jaime A. , Theis Martin , Willecke Klaus , Sáez Juan C.
Published: January 2007

Dendritic cells (DCs) in culture express at least connexin43, a protein subunit of gap junctions, and form gap junction channels, which could be important for T‐cells activation. Here, we evaluated whether DCs express connexins in vivo and also to identify components of their microenvironment that regulate the functional expression of gap junctions. In vivo studies were performed in lymph nodes of mice under control conditions or after skeletal muscle damage. In double immunolabeling studies, connexin45 was frequently detected in DEC205+ DCs in lymph nodes of control animals, whereas connexin43 was rarely found in DCs. However, connexin43 was upregulated in DCs after skeletal muscle damage. Upregulation of connexin43 gene expression by tissue damage was also confirmed in mice carrying a β‐galactosidase reporter gene in a connexin43 allele. The effect of several cytokines on the expression of functional gap junctions between cultured DCs was also tested. Under control conditions, cultured DCs did not communicate via gap junctions. However, after treatment with keratinocyte‐conditioned medium or cytokine mixtures containing at least TNF‐α and IL‐1β, they became transiently coupled through a pathway sensitive to octanol, a gap junction blocker. Cellular coupling induced by effective cytokine mixtures was prevented by IL‐6. Single cytokines (TNF‐α, IL‐1β, IFN‐γ, or IL‐6) or other mixtures than the described above did not induce coupling via gap junctions. Increased levels of connexin43 and connexin45 protein and mRNA accompanied the appearance of cellular coupling. These studies provide demonstration of connexin expression and regulation by specific danger signals in DCs. J. Cell. Physiol. 211: 649–660, 2007. © 2007 Wiley‐Liss, Inc.
BMP‐2 promotes differentiation of osteoblasts and chondroblasts in Runx2‐deficient cell lines
Authors: Liu Tingjiao , Gao Yuhao , Sakamoto Kei , Minamizato Tokutaro , Furukawa Keizo , Tsukazaki Tomoo , Shibata Yasuaki , Bessho Kazuhisa , Komori Toshihisa , Yamaguchi Akira
Published: January 2007

To investigate the molecular mechanism underlying the differentiation of osteoblasts and chondroblasts, we established a clonal cell lines, RD‐C6, from Runx2‐deficient mouse embryos. RD‐C6 cells expressed almost undetectable levels of phenotypes related to osteoblast and chondroblast differentiation at basal culture condition, whereas treatment with recombinant human bone morphogenetic protein‐2 (rhBMP‐2) or transduction of BMP‐2 by adenovirus effectively induced this cell line to express mRNA related to the differentiation of osteoblasts and chondroblasts including alkaline phosphatase, osteocalcin, and osterix. Transduction of Runx2 also induced the expression of these mRNA in RD‐C6 cells. BMP‐2 transduction increased expression levels of mRNA for Msx2 and Dlx5, but Runx2 transduction induced no significant increases in expression levels of these mRNA. Microarray analysis using RD‐C6 cells with or without rhBMP‐2 treatment demonstrated that BMP‐2 upregulated 66 genes including 13 transcription‐related molecules such as Id1, Id2, Id4, Hey1, Smad6, Smad7, and Msx2. To confirm bone and cartilage formation ability of RD‐C6 cells, we transplanted RD‐C6 cells into the peritoneal cavity of athymic mice using diffusion chambers with rhBMP‐2. RD‐C6 cells generated unmineralized cartilage but not bone. These results indicate that BMP‐2 induces Runx2‐deficient cells to express markers related to osteoblast and chondroblast differentiation using a Runx2‐independent pathway, but it failed to induce these cells to differentiate into bone‐forming osteoblasts and mature chondrocytes. J. Cell. Physiol. 211: 728–735, 2007. © 2007 Wiley‐Liss, Inc.
Preliminary studies on the effect of processing on the IgE reactivity of tomato products
Authors: Germini Andrea , Paschke Angelika , Marchelli Rosangela
Published: January 2007

Tomatoes and tomato products, obtained from a market, from companies or prepared in research laboratories, were tested in order to investigate how different processes could modulate the IgE reactivity of these products. The protein fraction of the samples was extracted by using a low‐temperature method in order to avoid degradation, and then separated on SDS PAGE to evaluate the protein profile. All the separated samples were blotted onto nitrocellulose membranes and then individually tested with pooled human sera that had been obtained from patients allergic to tomato, in order to evaluate the potential IgE binding of the protein bands. Heat treatments conventionally employed for the production of tomato‐based products were found to strongly degrade proteins thus dramatically reducing their IgE reactivity; characteristic protein profiles were found for specific processes such as hot and cold break. Ultra‐high‐pressure treatments were found to generally preserve the integrity of tomato proteins and this was reflected by the unaltered IgE reactivity observed. Copyright © 2007 Society of Chemical Industry
Toxicogenomic analysis of gene expression changes in human liver cells after exposure to environmentally friendly lubricants
Authors: Erlenkaemper B. , Eisentraeger A.
Published: January 2007

A lubricant based on synthetic esters and a mixture of this lubricant with additives and metals simulating the intake caused by usage were investigated with various ecotoxicological and genotoxicological tests. Tests with algae, daphnids and bacteria demonstrated an influence of the mixture on ecotoxicity. The genotoxicity tests, however, showed no effects for both samples. In addition, genetic effects were examined in detail by using gene expression profiles of HepG2 cells. Comparison of the set of regulated genes for early and late time points indicated a certain concordance between the genes up‐regulated after 6 and 24 hours of exposure. The correlation for the corresponding down‐regulated gene groups is slightly lower. Generally, the number of regulated genes is low (3–6%) demonstrating a marginal influence. The results indicate that the assessment of gene expression profiles, in addition to the quantification of toxic effects, may give important information on ways of toxic action of a substance. These data can be used in the development of new chemicals or products in order to minimize toxic effects. Copyright © 2007 John Wiley & Sons, Ltd.
Poly(2‐oxazoline)s: Alive and Kicking
Authors: Hoogenboom Richard
Published: January 2007

The development of various living/controlled polymerization techniques has allowed the synthesis of a large variety of well‐defined (co)polymers with varied polymer length, composition, and architecture, for example. Screening this large possible parameter space for a polymer with certain properties can be a very demanding process. Therefore, we aim to rapidly synthesize and systematically screen libraries of copolymers to determine structure‐property relationships that might allow the future design of novel (co)polymers with predictable properties. The cationic ring‐opening polymerization of 2‐oxazolines has been adapted for the synthesis of libraries of well‐defined (co)polymers. In this contribution, the optimization of the polymerization procedure using both high‐throughput experimentation and microwave irradiation is discussed. Subsequently, the microwave‐assisted synthesis of well‐defined libraries of (co)poly(2‐oxazoline)s and the determination of structure‐property relationships for these polymers is described. Moreover, the polymerization of a soy‐based 2‐oxazoline monomer will be illustrated as a ‘green’ approach to replace current oil‐based feedstock by renewable resources.

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Superior Nanoporous Polyimides via Supercritical CO2 Drying of Jungle‐Gym‐Type Polyimide Gels
Authors: Kawagishi Ken , Saito Hiromu , Furukawa Hidemitsu , Horie Kazuyuki
Published: January 2007

We report novel nanoporous polyimides formed from jungle‐gym‐type rigid polyimide gels by supercritical CO2 drying. By virtue of supercritical CO2 drying to avoid the collapse of nanostructure, porosity above 90 vol.‐% was achieved. We found a rich variety of nanoporous structures in the range of 50–800 nm such as crisp fragments, minute network, and highly‐connected beads. These characteristic structures were formed by the competitive progress of liquid‐liquid phase separation and crystallization induced due to the two chemical reactions of end‐crosslinking and thermal imidization during gelation.

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Swelling and Dissolution of Cellulose Part 1: Free Floating Cotton and Wood Fibres in N‐Methylmorpholine‐N‐oxide–Water Mixtures
Authors: Cuissinat Celine , Navard Patrick
Published: January 2007

Summary: Five modes describing the behaviour of cellulose fibres dipped in a chemical have been identified:

Mode 1: Fast dissolution by disintegration into fragments

Mode 2: Large swelling by ballooning, and dissolution

Mode 3: Large swelling by ballooning, and no dissolution

Mode 4: Homogeneous swelling, and no dissolution

Mode 5: No swelling and no dissolution

In the case of the behaviour of wood and cotton cellulose fibres in N‐methylmorpholine‐N‐oxide (NMMO) and water mixtures, four domains of water content have been identified. Below 17% of water up to monohydrate (13%), the fibres are disintegrated into rod‐like fragments and dissolve (mode 1). In NMMO – water mixtures containing 19–24% water, the cellulose fibres exhibit a heterogeneous swelling by forming balloons (composed of dissolved cellulose holds inside a membrane) separated with non‐swollen sections. The whole fibre will completely dissolve (mode 2) in four successive steps (growth of the balloons, burst of the balloons, dissolution of the non‐swollen sections and finally dissolution of the membrane). With still greater water contents (25–30%), only the ballooning phenomenon is observed, with a partial dissolution inside the balloon (mode 3). Above 35% of water, the fibres swell homogeneously and are not dissolving (mode 4).
Electrokinetic Investigations of Oriented Cellulose Polymers
Authors: Reischl Martin , Stana‐Kleinschek Karin , Ribitsch Volker
Published: January 2007

Summary: Electrokinetic investigations of different cellulosic fibres were reviewed with special emphasis on polymer composite materials and textile applications of cellulose fibres. The possibilities in the interpretation of zeta‐potential data regarding chemical and physical modification, specific adsorption, swelling and changes in hydrophobicity/hydrophilicity of cellulose polymers are discussed. Using recent data from literature, advantages and limitations of electrokinetic measurements of oriented polymers are described, finding that the zeta‐potential is a valuable parameter in polymer surface characterisation.