bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of Nox4 in osteoclasts
Authors: Yang Su , Zhang Yizhong , Ries William , Key Lyndon 
Published: April 2004

AbstractA new superoxide‐generating enzyme, NADPH oxidase 4 (Nox4), contributes to osteoclastic superoxide production. In this study, we demonstrated that Nox4 is expressed at a higher level in osteoclasts than that in precursor cells. This result suggested that Nox4 is upregulated during the differentiation and development of osteoclasts. Cotransfection of Nox4/P22 DNA resulted in enhanced superoxide production in osteoclasts, indicating that P22 may be a necessary factor for the Nox4 activity. In addition, expression of both cathepsin K and TRAP is increased significantly in osteoclasts cotransfected with Nox4/P22. Further study revealed that JNK was activated and that NF‐κB was inhibited in Nox4/P22 cotransfected osteoclasts. These findings suggest that superoxide and/or superoxide derived molecules may modulate the signal transduction pathways necessary for osteoclasts to function. © 2004 Wiley‐Liss, Inc.
C‐terminal region of protein kinase CK2α: How the structure can affect function and stability of the catalytic subunit
Authors: Grasselli Elena , Tomati Valeria , Bernasconi Marco V. , Nicolini Claudio , Vergani Laura 
Published: April 2004

AbstractA novel mutant of the catalytic α subunit of human protein kinase CK2 (CK2α) was designed in an attempt to clarify the role of the carboxylic‐terminal segment characteristic of vertebrates, excluding fish. Starting from the sequence alignments, we constructed a phylogenetic tree of the primary structure of CK2α. On this basis, we substituted two distal prolines with alanines (PA 382‐384). Theoretical calculations and spectropolarimetry measurements, performed both on native and mutant subunits, indicate an increased content of α‐helix after this double amino acidic substitution. In order to clarify the structure/function relationship of the C‐terminal region, we verified if the structural change affects the catalytic activity of CK2α. The mutant exhibits slightly increased phosphorylation efficiency, but reduced ability to transfer phosphate in comparison with the native subunit. At last, we compared the thermal stability of the mutant with respect to the native subunit and we tested the proteolytic degradability. The observation that the PA 382‐384 mutant exhibits an increased thermal and proteolytic stability suggests that this mutant could be employed to solve the three‐dimensional (3D) structure of human CK2α and to overcome difficulties in crystallizing the native form. © 2004 Wiley‐Liss, Inc.
Anti‐apoptotic effects of curcumin on photosensitized human epidermal carcinoma A431 cells
Authors: Chan Wen‐Hsiung , Wu Hsin‐Jung 
Published: April 2004

AbstractPhotodynamic treatment (PDT) can elicit a diverse range of cellular responses, including apoptotic cell death. Previously, we showed that PDT stimulates caspase‐3 activation and subsequent cleavage and activation of p21‐activated kinase 2 (PAK2) in human epidermal carcinoma A431 cells. Curcumin, the yellow pigment of Curcuma longa, is known to have anti‐oxidant and anti‐inflammatory properties. In the present study, using Rose Bengal (RB) as the photosensitizer, we investigated the effect of curcumin on PDT‐induced apoptotic events in human epidermal carcinoma A431 cells. We report that curcumin prevented PDT‐induced JNK activation, mitochondrial release of cytochrome c, caspase‐3 activation, and cleavage of PAK2. Using the cell permeable dye DCF‐DA as an indicator of reactive oxygen species (ROS) generation, we found that both curcumin and ROS scavengers (i.e., l‐histidine, a‐tocopherol, mannitol) abolished PDT‐stimulated intracellular oxidative stress. Moreover, all these PDT‐induced apoptotic changes in cells could be blocked by singlet oxygen scavengers (i.e., l‐histidine, a‐tocopherol), but were not affected by the hydroxyl radical scavenger mannitol. In addition, we found that SP600125, a JNK‐specific inhibitor, reduced PDT‐induced JNK activation as well as caspase‐3 activation, indicating that JNK activity is required for PDT‐induced caspase activation. Collectively, these results demonstrate that singlet oxygen triggers JNK activation, cytochrome c release, caspase activation and subsequent apoptotic biochemical changes during PDT and show that curcumin is a potent inhibitor for this process. © 2004 Wiley‐Liss, Inc.
Sampling protein conformations and pathways
Authors: Lei Ming , Zavodszky Maria I. , Kuhn Leslie A. , Thorpe M. F. 
Published: April 2004

AbstractProtein flexibility and rigidity can be analyzed using constraint theory, which views proteins as 3D networks of constraints involving covalent bonds and also including hydrophobic interactions and hydrogen bonds. This article describes an algorithm, ROCK (Rigidity Optimized Conformational Kinetics), which generates new conformations for these complex networks with many interlocked rings while maintaining the constraints. These new conformations are tracked for the flexible regions of a protein, while leaving the rigid regions undisturbed. An application to HIV protease demonstrates how large the flap motion can be. The algorithm is also used to generate conformational pathways between two distinct protein conformations. As an example, directed trajectories between the closed and the occluded conformations of the protein dihydrofolate reductase are determined. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1133–1148, 2004
Some remarks on domination
Authors: Archdeacon D. , Ellis‐Monaghan J. , Fisher D. , Froncek D. , Lam P.C.B. , Seager S. , Wei B. , Yuster R. 
Published: April 2004

AbstractWe prove a conjecture of Favaron et al. that every graph of order n and minimum degree at least three has a total dominating set of size at least n/2. We also present several related results about: (1) extentions to graphs of minimum degree two, (2) examining graphs where the bound is tight, and (3) a type of bipartite domination and its relation to transversals in hypergraphs. © 2004 Wiley Periodicals, Inc. J Graph Theory 46: 207–210, 2004
Edge colorings of complete graphs without tricolored triangles
Authors: Gyárfás András , Simony Gábor 
Published: April 2004

AbstractWe show some consequences of results of Gallai concerning edge colorings of complete graphs that contain no tricolored triangles. We prove two conjectures of Bialostocki and Voxman about the existence of special monochromatic spanning trees in such colorings. We also determine the size of largest monochromatic stars guaranteed to occur. © 2004 Wiley Periodicals, Inc. J Graph Theory 46: 211–216, 2004
Effects of phosphorus and zinc fertilizer on cadmium uptake and distribution in flax and durum wheat
Authors: Jiao You , Grant Cynthia A , Bailey Loraine D 
Published: April 2004

AbstractCadmium accumulation in crops presents a potential risk to human health. To understand the difference between dicotyledonous and monocotyledonous species in respect of Cd accumulation, and to develop fertilizer management practices to minimise Cd uptake, a growth chamber study was conducted to evaluate the interactive effects of Cd concentration in phosphate and Zn fertilizer on Cd uptake in flax (Linum usitatissimum L) and durum wheat (Triticum turgidum L). Cadmium concentration was higher in flax than durum wheat shoots. Cadmium concentration was lower and Zn concentration higher in the flax seed and durum wheat grain than in the root, shoot or straw of both species. These results suggest that flax has comparatively ineffective barriers discriminating against the transport of Cd from the root to the shoot via the xylem, and that both crops may restrict Cd translocation to the seed/grain via the phloem. Commercial grade monoammonium phosphate (NH4H2PO4) or triple superphosphate (Ca(H2PO4)2) produced higher seed Cd concentrations than did reagent grade P in flax but not in durum wheat. Application of P significantly decreased seed/grain Zn concentration and increased seed/grain Cd concentration. Zinc addition at 20 mg Zn kg−1 soil with P decreased seed/grain Cd concentration (average 42.2% for flax, 65.4% for durum wheat), Cd accumulation (average 37.2% for flax, 62.4% for durum wheat) and Cd translocation to the seed/grain (average 20.0% for flax, 34.5% for durum wheat) in both crops. These results indicate that there is an antagonistic effect of Zn on Cd for root uptake and distribution within the plant. Copyright © 2004 Society of Chemical Industry
Effect of different packing treatments on the microbiological and physicochemical characteristics of untreated green olives of the Conservolea cultivar
Authors: Panagou Efstathios Z 
Published: April 2004

AbstractMicrobiological, physicochemical and organoleptic changes were studied in non‐pasteurised samples of untreated green olives cv Conservolea stored at 20 °C for 180 days under different preservation treatments (acidified brine and modified atmospheres). The microbial flora consisted of lactic acid bacteria and yeasts, while no enterobacteria and pseudomonads were enumerated in any package. Although no thermal treatment was applied to the packages, no sediment formation was observed due to the growth of propionic bacteria. Olives packed in brine supplemented with 0.3% lactic and 0.3% citric acids presented the highest acidity, the lowest brine and flesh pH and the lowest dark brine colour as measured by the parameter A440−A700. Olives packed in modified atmospheres (vacuum, 40% CO2/30% O2/30% N2 and air) presented a progressive loss of fruit firmness and colour with time. At the end of the storage period, olives packed in aerobic conditions and 40% CO2/30% O2/30% N2 presented the lowest firmness and skin colour and were unacceptable to the panellists. The best quality characteristics were maintained in vacuum‐packed olives, as indicated by the higher organoleptic scores. Firmness degradation followed first‐order kinetics (r2 > 0.980) and the expected shelf‐life was 23, 15 and 9 months for olives packed in vacuum, 40% CO2/30% O2/30% N2 and air respectively. Copyright © 2004 Society of Chemical Industry
Synthesis and Characterisation of Side‐Chain Liquid Crystalline Poly[1‐({[(4‐cyano‐4′‐biphenyl)oxy]alkyl}oxy)‐2,3‐epoxypropane]
Authors: Han Xiangen , Shanks Robert A. , Pavel Dumitru 
Published: April 2004

AbstractSummary: A new series of side‐chain liquid‐crystal polymers, the poly[1‐({[(4‐cyano‐4′‐biphenyl)oxy]alkyl}oxy)‐2,3‐epoxypropane], has been synthesized in which the spacer length is varied from 2 to 8 methylene units. The synthesis used for the chemical modification of polyepichlorohydrin (PECH) involved the phase transfer catalyzed etherification of the chloromethyl groups with sodium 4‐cyano‐4′‐biphenoxide and lithium n‐(4‐cyano‐4′‐oxybiphenyl)‐alkanoates. All the resulting polymers (except polymers 7 and 8), including that without spacer, characterized by 1H NMR, and IR, exhibit thermotropic liquid crystalline mesomophism. The thermal behavior of the polymers has been characterized using differential scanning calorimetry (DSC) and polarized light microscopy (POM) equipped with hot‐stage. A more pronounced odd‐even effect in the clearing temperatures is observed on increasing the spacer length in which the odd members display slightly higher values, which were also dependent on the substitution degree of PECH. The flexible PECH chain assists nematic LC formation compared with other more rigid backbone polymers where a smectic phase is often encountered with the same mesogen. A comparison of the thermal properties of the cyanobiphenyl based series reported here. Polyacrylate (PA) and poly(methacrylate)‐based (PMA) SCLCPs containing 4‐cyanobiphenyl as the mesogenic unit are consistent with the general rule that increasing backbone flexibility for a given mesogenic unit and spacer length enhance the clearing temperature. This was not found from the PECH‐based series, which show the lower clearing temperature than the PMA and PA series, even though they have more flexible backbone than PA and PMA series. So the clearing temperature is not solely determined by the flexibility of the backbone.Schlieren textures of PECHOC2‐B taken at 110 °C (cooling from isotropic phase after annealing 1 h).magnified imageSchlieren textures of PECHOC2‐B taken at 110 °C (cooling from isotropic phase after annealing 1 h).
Variation on a theme of Schütte
Authors: Jäger Gerhard , Probst Dieter 
Published: April 2004

AbstractLet ≺ be a primitive recursive well‐ordering on the natural numbers and assume that its order‐type is greater than or equal to the proof‐theoretic ordinal of the theory T. We show that the proof‐theoretic strength of T is not increased if we add the negation of the statement which formalizes transfinite induction along ≺. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
N,N‐Dimethylformamide Additions to the Solution for the Electrospinning of Poly(ε‐caprolactone) Nanofibers
Authors: Hsu Chen‐Ming , Shivkumar Satya 
Published: April 2004

AbstractSummary: Additives that exhibit polyelectrolyte behavior such as N,N‐dimethylformamide (DMF) may improve the electrospinning characteristics of viscoelastic polymer solutions. DMF additions to the solution lead to extensive jet splaying, thereby reducing the fiber diameter significantly. Nanofibrous structures with diameters of the order of 150 nm can be produced by the addition of about 10 vol.‐% DMF to the solvent (chloroform). DMF additions also yield a narrow, unimodal distribution of fibers, compared to the bimodal distribution typically detected in electrospun polymers.Jet breakdown without (left) and with DMF addition to the solution.imageJet breakdown without (left) and with DMF addition to the solution.
Morphology and Tensile Strength Prediction of in situ Microfibrillar Poly(ethylene terephthalate)/Polyethylene Blends Fabricated via Slit‐Die Extrusion‐Hot Stretching‐Quenching
Authors: Li Zhong‐Ming , Yang Wei , Xie Bang‐Hu , Shen Kai‐Zhi , Huang Rui , Yang Ming‐Bo 
Published: April 2004

AbstractSummary: In situ microfibrillar poly(ethylene terephthalate) (PET)/polyethylene blends (MRB) were successfully fabricated by slit‐die extrusion‐hot stretching‐quenching. The morphology of this new material is mainly influenced by the composition and the hot stretching. Appropriate PET concentrations and a comparatively high hot stretching ratio could facilitate the fibrillation of PET domains during processing. The expression employed for prediction of the tensile strength for the microfibrillar blend was proved to be desirable. The prediction was, generally, in agreement with the experimental results, although the values of some parameters were approximated.SEM micrograph of the cryofractured surface of the in situ microfibrillar PET/PE blend after injection molding.imageSEM micrograph of the cryofractured surface of the in situ microfibrillar PET/PE blend after injection molding.
Preparation and Combustion Properties of Flame Retardant Styrene‐Butyl Acrylate Copolymer/Graphite Oxide Nanocomposites
Authors: Zhang Rui , Hu Yuan , Xu Jiayan , Fan Weicheng , Chen Zuyao , Wang Qinan 
Published: April 2004

AbstractSummary: Styrene‐butyl acrylate copolymer (St‐BA)/graphite oxide (GO) nanocomposites and St‐BA/GO/MPP [melamine poly(metaphosphate)] composites were prepared via an intercalation process by the ball‐milling method and characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and field emission scanning electron microanalyzer (SEM). Cone calorimetry experiments were carried out to evaluate their flammability. The cone calorimetry data suggested that the addition of GO can decrease the heat release rate of St‐BA copolymers significantly. Furthermore, there was also a synergistic effect on the fire retardant property by the combination of GO and MPP. However, no prominent effect of the GO content on the reduction of peak heat release rate (HRR) in nanocomposites could be found.SEM image of the fractured surface of St‐BA/GO/MPP hybrid.imageSEM image of the fractured surface of St‐BA/GO/MPP hybrid.
A Kinetic Study on the Thermal Degradation of Multi‐Walled Carbon Nanotubes‐Reinforced Poly(propylene) Composites
Authors: Seo Min‐Kang , Park Soo‐Jin 
Published: April 2004

AbstractSummary: The influence of the multi‐walled carbon nanotubes (MWNTs) content on the thermal degradation behavior of MWNTs‐reinforced poly(propylene) (PP) composites was investigated by using non‐isothermal thermogravimetric analysis (TGA). Kinetic parameters of degradation were evaluated by using the Flynn‐Wall‐Ozawa iso‐conversional method and the pseudo first‐order method. As a result, compared with pristine PP, MWNTs‐PP nanocomposites have lower peak temperatures of degradation, narrower degradation temperature ranges and a higher amount of residual weight at the end of the degradation, which is likely to be a result of specific interactions between complimentary functional groups. The values of the reaction order of MWNTs‐PP nanocomposites determined by the Kissinger method are close to 1 in the non‐isothermal degradation process. There is a good correlation between the Ea in region II and the peak temperature of degradation for the composites.Activation energies for degradation of different contents of MWNTs‐filled PP nanocomposites as a function of conversion.imageActivation energies for degradation of different contents of MWNTs‐filled PP nanocomposites as a function of conversion.
Structure and Mechanical Properties of Composites of Poly(6‐hexanelactam) Combining Solid Tribological Additives and Reinforcing Components
Authors: Horský Jaroslav , Kolařík Jan , Fambri Luca 
Published: April 2004

AbstractSummary: Three types of composites of polyamide 6 (PCL) with hybrid tribological additives were synthesized via anionic adiabatic “in situ” polymerization of 6‐hexanelactam (ε‐caprolactam) initiated with metallic sodium and activated with either cyclic trimer of phenyl isocyanate or diphenylmethane 4,4′‐diisocyanate. Combinations of the additives and their maximum applied concentrations (in wt.‐%) were the following: MoS2/graphite(G)/oil(O) (5/16/9), short carbon fibers (CF)/G/O (5/20/10), and copper phthalocyanine (CPC) (7). Dynamic mechanical thermal analysis (DMTA) indicates a secondary (β) transition at about −65 °C and the main (α) transition at temperatures close to 20 °C; the storage modulus passes through a shallow maximum as a function of the total content of additives. Tensile creep and indentation creep concurrently evidenced some increase in compliance with rising fraction of incorporated compounds. Stress‐strain tests in flexure show that flexural strength and toughness monotonically decreased with the content of MoS2/G/O or CF/G/O, whereas the flexural modulus passed through a flat maximum. On the other hand, the strength and modulus were decreasing with CPC content, while toughness and Charpy impact tests showed some improvement.Flexural toughness afU as a function of filler content Cad in adiabatic anionic polymerization of 6‐hexanelactam.imageFlexural toughness afU as a function of filler content Cad in adiabatic anionic polymerization of 6‐hexanelactam.
Simple and Fast Organic Device Encapsulation Using Polyisobutene
Authors: Toniolo Rogério , Hümmelgen Ivo A. 
Published: April 2004

AbstractSummary: We demonstrate the use of polyisobutene (PIB) in a glass encapsulation method suitable for organic devices. The PIB viscosity at environmental temperatures provides a fast and non‐aggressive passivant layer formation method for device protection with glass. Due to its fully aliphatic character, PIB is suitable for passivating organic light‐emitting and photovoltaic devices. The observed preservation of encapsulated Ca films demonstrates the PIB suitability for air‐unstable metals passivation. Stable I(V) characteristics and increased operational lifetime were observed in PIB‐encapsulated organic devices. This encapsulation method is cheap, simple, and dispenses intensive equipment use, so that it is appropriate even for laboratories with restricted experimental facilities.Setup used for Ca samples testing. The right Ca contact was encapsulated with PIB and a glass cover plate (dashed square). The electrical diagram of the apparatus used to obtain the resistance behavior is also shown.imageSetup used for Ca samples testing. The right Ca contact was encapsulated with PIB and a glass cover plate (dashed square). The electrical diagram of the apparatus used to obtain the resistance behavior is also shown.
Riesz potential and Sobolev embeddings on generalized Lebesgue and Sobolev spaces Lp(·) and Wk,p(·)
Authors: Diening Lars 
Published: April 2004

AbstractWe study the Riesz potentials Iαf on the generalized Lebesgue spaces Lp(·)(ℝd), where 0 < α < d and Iαf(x) ≔ ∫ |f(y)| |x – y|α – d dy. Under the assumptions that p locally satisfies |p(x) – p(x)| ≤ C/(– ln |x – y|) and is constant outside some large ball, we prove that Iα : Lp(·)(ℝd) → Lp♯(·)(ℝd), where $ {\textstyle {1 \over {p ^{\sharp} (x)}} = {1 \over {p(x)}} - {\alpha \over d}} $. If p is given only on a bounded domain Ω with Lipschitz boundary we show how to extend p to $ \tilde p $ on ℝd such that there exists a bounded linear extension operator ℰ : W1,p(·)(Ω) ↪ $ W^{1, {\tilde p}} $(ℝd), while the bounds and the continuity condition of p are preserved. As an application of Riesz potentials we prove the optimal Sobolev embeddings Wk,p(·)(ℝd) ↪Lp*(·)(Rd) with $ {\textstyle {1 \over {p ^{\ast} (x)}} = {1 \over {p(x)}} - {k \over d}} $ and W1,p(·)(Ω) ↪ Lp*(·)(Ω) for k = 1. We show compactness of the embeddings W1,p(·)(Ω) ↪ Lq(·)(Ω), whenever q(x) ≤ p*(x) – ε for some ε > 0. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Harmonic functions on the real hyperbolic ball II Hardy‐Sobolev and Lipschitz spaces
Authors: Grellier Sandrine , Jaming Philippe 
Published: April 2004

AbstractIn this paper, we pursue the study of harmonic functions on the real hyperbolic ball started in [13]. Our focus here is on the theory of Hardy‐Sobolev and Lipschitz spaces of these functions. We prove here that these spaces admit Fefferman‐Stein like characterizations in terms of maximal and square functionals. We further prove that the hyperbolic harmonic extension of Lipschitz functions on the boundary extend into Lipschitz functions on the whole ball. In doing so, we exhibit differences of behaviour of derivatives of harmonic functions depending on the parity of the dimension of the ball and on the parity of the order of derivation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boundedness in nonlinear oscillations
Authors: Yang Xiaojing 
Published: April 2004

AbstractIn this paper, the boundedness of all solutions of the nonlinear differential equation(φp(x′))′ + αφp(x+) – βφp(x–) + f(x) = e(t)is studied, where φp(u) = |u|p–2 u, p ≥ 2, α, β are positive constants such that $ \alpha ^{-{1 \over p}} + \beta ^{-{1 \over p }} $ = 2w–1 with w ∈ ℝ+\ℚ, f is a bounded C5 function, e(t) ∈ C6 is 2πp‐periodic, x+ = max{x, 0}, x– = max{–x, 0}. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stereospecific Polymerization of Isoprene with Nd(BH4)3(THF)3/MgBu2 as Catalyst
Authors: Bonnet Fanny , Visseaux Marc , Pereira Angela , Bouyer Frédéric , Barbier‐Baudry Denise 
Published: April 2004

AbstractSummary: The neodymium trisborohydride Nd(BH4)3(THF)3 (THF = tetrahydrofuran) has been used as a catalyst precursor for isoprene polymerization for the first time. Associated to an excess of Al(Et)3, the resulting catalyst is moderately active, giving a mixture of cis‐ and trans‐ polymer. Addition of a stoichiometric amount of MgBu2 to Nd(BH4)3(THF)3 affords a stereospecific catalyst providing trans‐1,4‐polyisoprene, more than 96% regular. That dual component Nd/Mg system also shows a better efficiency and good control of the molecular weights. A molecular structure is tentatively attributed to a bimetallic active species, based on 1H NMR experiments.Possible Nd/Al and Nd/Mg active initiating species.imagePossible Nd/Al and Nd/Mg active initiating species.