bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tantalum as a buffer layer in diamond‐like carbon coated artificial hip joints
Authors: Kiuru Mirjami , Alakoski Esa , Tiainen Veli‐Matti , Lappalainen Reijo , Anttila Asko 
Published: June 2003

AbstractThe acid resistance of tantalum coated and uncoated human hip joint prostheses was studied with commercial CrCoMo acetabular cups. The samples were exposed to 10% HCl solution and the quantities of dissolved Cr, Co, and Mo were measured with proton‐induced X‐ray emission (PIXE). The absolute quantities were obtained with the use of Cr and Se solution standards. Tantalum coatings (thicknesses 4–6 μm) were prepared in vacuum with magnetron sputtering. Tantalum coating decreased the corrosion rate by a factor of 106. As a spinoff from recent wear tests on artificial hip joints it was shown that tantalum has excellent mechanical properties as an intermediate layer of diamond‐like carbon (DLC) coatings. When tantalum was tested together with DLC on three metal‐on‐metal hip joint pairs in a hip simulator, no observable defects occurred during 15 million walking cycles with a periodic 50–300‐kg load (Paul curve). © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 425–428, 2003
Inverse relationship between tensile bond strength and dimensions of bonded area
Authors: Escribano Nuria I. , Del‐Nero Maria O. , de la Macorra Jose C. 
Published: June 2003

AbstractIt is a known fact that there is a relationship between magnitude of bonded area and laboratory tensile test results. This relationship has been described for a range of areas between 1 and 10 mm2, in extracted, nonperfused teeth. The aim of this study is to test this relationship in perfused teeth, with bonded areas ranging from 0.7 to 110.9 mm2. Dentin of 92 sound third human molars was exposed and perfused, and three groups of bonded areas (BA) were delimited: small (0.69–1.89 mm2), medium (8.66–19.54 mm2), and large (58.91–110.86 mm2). Tensile bond strength (TBS) of three adhesive restorative systems was found. The best nonlinear curve estimation was searched (SPSS 9.0) between TBS and BA, for each and all materials. The best estimation was, for all materials, TBS = 4.17 + 10.35/BA (p < 0.0001). © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 419–424, 2003
Difference in polymerization color changes of dental resin composites by the measuring aperture size
Authors: Lee Yong‐Keun , Lim Bum‐Soon , Kim Cheol‐We 
Published: June 2003

AbstractThe objective of this study was to evaluate the influence of the illuminating/viewing aperture diameter of 11 mm/8 mm and 3 mm/3 mm and measuring geometry on the color and polymerization color changes of dental resin composites. Color of resin composites of 12 mm in diameter was measured on a reflection spectrophotometer with SCE and SCI geometry under D65 illumination. Before polymerization, difference in the three‐color coordinates by the material was prominent in spite of the fact that the shade designation of all materials was the same. After polymerization, L* value decreased in hybrid composites but not in packable composites, and changes in a* value were small. When the same aperture size was used, polymerization color change with the SCE was generally higher than those with the SCI. Measured color was different by the aperture size, and the color difference was 16.82–27.05 before polymerization and 20.09–28.51 after polymerization. General trends of polymerization color change were similar in both aperture sizes. Polymerization color changes with 3‐mm aperture size were higher than those with 8‐mm aperture size in hybrid resin composites in both geometries (p < 0.05); however, the color change was material dependent in the case of packable resin composites. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 373–378, 2003
Use of injectable calcium‐phosphate cement for the fixation of titanium implants: An experimental study in goats
Authors: Ooms E. M. , Wolke J. G. C. , van der Waerden J. P. C. M. , Jansen J. A. 
Published: June 2003

AbstractThis in vivo study evaluated the fixation of two types of titanium implants with the use of an injectable calcium‐phosphate (CaP) cement. The cement was either used to create a cement mantle (Type A implant) or as an additive to press‐fit placed titanium plasma sprayed implants (Type B implant). The implants were placed in trabecular bone of the medial femoral condyle of goats and left in place for 2 and 10 weeks. Mechanical evaluation of the implant fixation was done by torque testing. This showed that for the Type A implants the calcium‐phosphate cement's performance was significantly inferior (P < 0.05) to that of polymethylmethacrylate cement fixation. For the two‐week Type B implants a significant increase (P < 0.05) in failure load was found for calcium‐phosphate cemented implants compared with just press‐fitted Type B implants. Histological evaluation revealed that for Type A implants, failure during torque testing occurred at the implant–cement interface. In contrast, for Type B implants, failure occurred in the bone–implant interface for press‐fit–placed devices and in the cement layer for CaP‐cemented devices. Further, the CaP cement was found to be overgrown with new formed bone already after 2 weeks of implantation. The cement showed resorption due to regular bone remodeling. On the basis of these observations, it was concluded that the use of injectable CaP cement might facilitate earlier loading of press‐fit inserted titanium implants. Nevertheless, the results have to be confirmed in dynamical mechanical as well as loaded in vivo studies. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 66B: 447–456, 2003
A formula for the number of Steiner quadruple systems on 2npoints of 2‐rank 2n−n
Authors: Tonchev Vladimir D. 
Published: June 2003

AbstractAssmus [1] gave a description of the binary code spanned by the blocks of a Steiner triple or quadruple system according to the 2‐rank of the incidence matrix. Using this description, the author [13] found a formula for the total number of distinct Steiner triple systems on 2n−1 points of 2‐rank 2n‐n. In this paper, a similar formula is found for the number of Steiner quadruple systems on 2npoints of 2‐rank 2n‐n. The formula can be used for deriving bounds on the number of pairwise non‐isomorphic systems for largen, and for the classification of all non‐isomorphic systems of small orders. The formula implies that the number of non‐isomorphic Steiner quadruple systems on 2npoints of 2‐rank 2n‐ngrows exponentially. As an application, the Steiner quadruple systems on 16 points of 2‐rank 12 are classified up to isomorphism. © 2003 Wiley Periodicals, Inc. J Combin Designs 11: 260–274, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10036
A lower bound on the number of Semi‐Boolean quadruple systems
Authors: Buratti Marco , Del Fra Alberto 
Published: June 2003

AbstractA Steiner quadruple system of order 2nisSemi‐Boolean(SBQS(2n) in short) if all its derived triple systems are isomorphic to the point‐line design associated with the projective geometryPG(n−1, 2). We prove by means of explicit constructions that for anyn, up to isomorphism, there exist at least 2⌊ 3(n−4)/2⌋regularand resolvable SBQS(2n). © 2003 Wiley Periodicals, Inc. J Combin Designs 11: 229–239, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10050
CTGF/Hcs24, hypertrophic chondrocyte‐specific gene product, interacts with perlecan in regulating the proliferation and differentiation of chondrocytes
Authors: Nishida Takashi , Kubota Satoshi , Fukunaga Tomohiro , Kondo Seiji , Yosimichi Gen , Nakanishi Tohru , Takano‐Yamamoto Teruko , Takigawa Masaharu 
Published: June 2003

AbstractConnective tissue growth factor/hypertrophic chondrocyte‐specific gene product 24 (CTGF/Hcs24) plays important roles in the control of the proliferation and differentiation of chondrocytes in vitro. To clarify the mechanisms of regulation by CTGF/Hcs24 with respect to cartilage metabolism, we investigated the interaction between CTGF/Hcs24 and heparan sulfate proteoglycan perlecan. An immunofluorescence study showed that CTGF/Hcs24 was colocalized with heparan sulfate and perlecan in human chondrosarcoma‐derived chondrocytic cell line HCS‐2/8 in vitro. Northern blot analysis showed that perlecan, syndecan‐1, ‐2, and ‐4 transcripts were detected in HCS‐2/8 cells. Particularly, expression of the perlecan gene increased markedly in HCS‐2/8 cells by recombinant CTGF/Hcs24 (rCTGF/Hcs24) treatment. We also found that CTGF/Hcs24 interacted with perlecan from HCS‐2/8 cells in vitro. Furthermore, CTGF/Hcs24‐stimulated gene expression of the aggrecan gene, as well as DNA/proteoglycan synthesis, was diminished when HCS‐2/8 cells were pretreated with heparinase, indicating that the effects of CTGF/Hcs24 on chondrocytes occurred through the interaction between CTGF/Hcs24 and heparan sulfate on the cells. An in vivo study using mouse growth plate revealed that CTGF/Hcs24 produced by hypertrophic chondrocytes was localized from the proliferative to the hypertrophic zone, whereas perlecan was predominantly localized in the prehyphertrophic zone. Consistent with such findings in vivo, the binding of 125I‐rCTGF/Hcs24 to maturing chondrocytes was at higher levels than that to chondrocytes in hypertrophic stages. These findings suggest that CTGF/Hcs24 produced in the hypertrophic region may act on chondrocytes in the proliferative and maturative zone via some heparan sulfate proteoglycan, such as perlecan. J. Cell. Physiol. 196: 265–275, 2003. © 2003 Wiley‐Liss, Inc.
Pro‐apoptotic ASY/Nogo‐B protein associates with ASYIP
Authors: Qi Bing , Qi Yipeng , Watari Akihiro , Yoshioka Naohisa , Inoue Hirokazu , Minemoto Yuzuru , Yamashita Katsumi , Sasagawa Toshiyuki , Yutsudo Masuo 
Published: June 2003

AbstractWe have previously shown that ectopic expression of the ASY/Nogo‐B gene induced apoptosis in various cancer cell lines. Nogo‐A, a splice variant of the ASY, has been reported to have an inhibitory effect on neuronal regeneration in the central nervous system. To investigate the mechanism of ASY‐induced apoptosis or inhibition of neuronal regeneration, we cloned a cDNA for the ASY‐interacting protein from the human cDNA library using the yeast two‐hybrid method, and obtained a cDNA we designated as ASYIP. The ASYIP protein contains two hydrophobic regions and a double lysine endoplasmic reticulum (ER) retrieval motif at its C‐terminus, which was shown to be identical to RTN3, a reticulon family protein of unknown function. We showed that ASY and ASYIP proteins formed a complex also in human cells. Mutational analysis indicated that both of the hydrophobic regions of the ASYIP protein were required for the association. By immunofluorescence analysis, the ASYIP protein was shown to be co‐localized with ASY in the ER. Characterization of the ASYIP gene may be very useful in clarifying the mechanism of ASY‐induced apoptosis or Nogo‐involved inhibition of neuronal regeneration in the central nervous system. J. Cell. Physiol. 196: 312–318, 2003. © 2003 Wiley‐Liss, Inc.
Perivitelline space: Does it play a role in blocking polyspermy in mammals?
Authors: Talbot P. , Dandekar Pramila 
Published: June 2003

AbstractThe perivitelline space of mammalian oocytes changes in size and composition during preimplantation development. Often overlooked in the past, this space contains a hyaluronan‐rich extracellular matrix prior to fertilization and a cortical granule envelope following release of the cortical granules at fertilization. The hyaluronan‐containing matrix of unfertilized oocytes is well developed in some species such as opossums and humans but is scant in rodents including the hamster and mouse. The significance of the hyaluronan‐rich matrix, which attaches to the plasma membrane of the oocytes, is not fully understood. However, hyaluronan, which can inhibit membrane fusion, is present in the perivitelline space (PVS) of unfertilized oocytes and must be negotiated by the fertilizing sperm. Following fertilization, the cortical granule envelope forms as the cortical granules disperse, thereby causing the PVS to increase significantly in size. Calcium is important in the dispersion of the cortical granules following exocytosis. Once formed, the cortical granule envelope in some species is about the same thickness as the zona pellucida, but it is not readily visualized unless it is stained with fluorescent probes or examined ultrastructurally after following stabilization with ruthenium red. The envelope contains proteins that remain in the PVS until the time of blastocyst hatching. Although little work has been done on the functions of the cortical granule envelope, several studies are consistent with the idea that it plays a role in blocking polyspermy. While nicotine increases polyspermy in sea urchins, its effects on polyspermy in human smokers have not been characterized, but could be addressed in human in vitro fertilization labs. Microsc. Res. Tech. 61:349–357, 2003. © 2003 Wiley‐Liss, Inc.
Isometric cycles, cutsets, and crowning of bridged graphs
Authors: Jiang Tao , Kim Seog‐Jin , West Douglas B. 
Published: June 2003

AbstractA graph G is bridged if every cycle C of length at least 4 has vertices x,y such that dG(x,y) < dC(x,y). A cycle C is isometric if dG(x,y) = dC(x,y) for all x,y ∈ V(C). We show that every graph contractible to a graph with girth g has an isometric cycle of length at least g. We use this to show that every minimal cutset S in a bridged graph G induces a connected subgraph. We introduce a “crowning” construction to enlarge bridged graphs. We use this to construct examples showing that for every connected simple graph H with girth at least 6 (including trees), there exists a bridged graph G such that G has a unique minimum cutset S and that G[S] = H. This provides counterexamples to Hahn's conjecture that dG(u,v) ≤ 2 when u and v lie in a minimum cutset in a bridged graph G. We also study the convexity of cutsets in bridged graphs. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 161–170, 2003
On Moore bipartite digraphs
Authors: Fiol M. A. , Gimbert J. , Gómez J. , Wu Y. 
Published: June 2003

AbstractIn the context of the degree/diameter problem for directed graphs, it is known that the number of vertices of a strongly connected bipartite digraph satisfies a Moore‐like bound in terms of its diameter k and the maximum out‐degrees (d1, d2) of its partite sets of vertices. It has been proved that, when d1d2 > 1, the digraphs attaining such a bound, called Moore bipartite digraphs, only exist when 2 ≤ k ≤ 4. This paper deals with the problem of their enumeration. In this context, using the theory of circulant matrices and the so‐called De Bruijn near‐factorizations of cyclic groups, we present some new constructions of Moore bipartite digraphs of diameter three and composite out‐degrees. By applying the iterated line digraph technique, such constructions also provide new families of dense bipartite digraphs with arbitrary diameter. Moreover, we show that the line digraph structure is inherent in any Moore bipartite digraph G of diameter k = 4, which means that G = L G′, where G′ is a Moore bipartite digraph of diameter k = 3. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 171–187, 2003
Two‐factors each component of which contains a specified vertex
Authors: Egawa Yoshimi , Enomoto Hikoe , Faudree Ralph J. , Li Hao , Schiermeyer Ingo 
Published: June 2003

AbstractIt is shown that if G is a graph of order n with minimum degree δ(G), then for any set of k specified vertices {v1,v2,…,vk} ⊂ V(G), there is a 2‐factor of G with precisely k cycles {C1,C2,…,Ck} such that vi ∈ V(Ci) for (1 ≤ i ≤ k) if $n = 3K,\delta(G)\ge\,{{7k-2}\over {3}}$ or 3k + 1 ≤ n ≤ 4k, $\delta (G)\,\ge\,{{2n+k-3}\over {3}}$ or 4k ≤ n ≤ 6k − 3,δ(G) ≥ 3k − 1 or n ≥ 6k − 3, $\delta(G)\ge {{n}\over {2}}$. Examples are described that indicate this result is sharp. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 188–198, 2003
A newly recognized intrinsically knotted graph
Authors: Foisy Joel 
Published: June 2003

AbstractIn [Adams, 1994; The Knot Book], Colin Adams states as an open question whether removing a vertex and all edges incident to that vertex from an intrinsically knotted graph must yield an intrinsically linked graph. In this paper, we exhibit an intrinsically knotted graph for which there is a vertex that can be removed, and the resulting graph is not intrinsically linked. We further show that this graph is minor minimal with respect to being intrinsically knotted. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 199–209, 2003
Study of molecular structures for arylidene derivatives of 3R‐methylcyclohexanone by 1H NMR and molecular simulation
Authors: Pivnenko Nikolay S. , Krivoshey Alexander I. , Kutulya Lidiya A. 
Published: June 2003

AbstractConformational states of the cyclohexanone ring were established for 3R‐methyl‐6‐(4‐phenylbenzylidene)cyclohexanone and several 2,6‐bis(4‐X‐benzylidene)‐3R‐methylcyclohexanones (X = Br, OCOCH3 and C6H5) by 1H NMR spectroscopy combined with molecular simulation using the semi‐empirical methods AM1 and PM3. The first compound studied contains only one arylidene group, and exists predominantly in a chair conformation of the cyclohexanone ring with an equatorial orientation of the methyl substituent in C6D6 and CDCl3 solutions at room temperature (22–23 °C). In contrast, the 2,6‐bis(arylidene) derivatives of 3R‐methylcyclohexanone preferentially adopt conformations with an axially oriented methyl group. The extent of twisting of enone fragments was also characterized for the compounds studied based on simulation results and comparison of chemical shifts for the arylidene protons of appropriate model compounds. Copyright © 2003 John Wiley & Sons, Ltd.
Nitroxide spin probe study of probe size, hydrogen bonding and polymer matrix rigidity effects on poly(acrylic acid)/poly(ethylene oxide) complexes
Authors: Tan Li , Chen Shiming , Ping Zhenghua , Shen Yimin 
Published: June 2003

AbstractAn electron spin resonance (ESR) spin probe study was performed on 1 : 1 by weight poly(acrylic acid) (PAA)/poly(ethylene oxide) (PEO) complex over the 100–450 K temperature range with a series of tetramethylpiperidyloxy‐based spin probes. Measurements of the parameters T5mT, Ta and Td demonstrated the effects of probe size and the strength of hydrogen bonding. The probes in the series Tempone, Tempo, Tempol and Tamine (respectively 4‐oxo‐, unsubstituted, 4‐hydroxy‐ and 4‐amino‐2,2,6,6,‐tetramethylpiperidine ‐1‐oxyl) displayed noticeable increases in the hydrogen‐bonding effect, as indicated by Ta and Td. These increases correlated with increasing hydrogen bond acceptor strength. On the other hand, as the probe size became larger, T5mT gradually increased due to the free volume decrease. These effects were analyzed using the established theoretical relationship of T5mT to probe volume expressed by f. Meanwhile, in order to investigate the effect of polymer matrix rigidity, a similar study was performed with a nitroxide spin probe, 2,2,6,6‐tetramethyl‐1‐piperidine‐1‐oxyl (Tempo), on PAA/PEO complexes of different weight compositions. The quantitative fast motion fraction in the composite ESR spectrum was calculated. The influence of changes in the composition of PAA on the molecular mobility was characterized by changes of the spectral parameters $2A^{'}_{zz}$ and τc. The molecular mobility was shown to diminish with increasing content of PAA in PAA/PEO blends duo to the restriction of the polymer matrix rigidity increase. Copyright © 2003 John Wiley & Sons, Ltd.
Combined use of nuclear magnetic resonance and infrared spectroscopy for studying recognition processes between amphenicolic antibiotics and albumin
Authors: Martini Silvia , Bonechi Claudia , Magnani Agnese , Marchettini Nadia , Corti Piero , Corbini Gianfranco , Rossi Claudio 
Published: June 2003

AbstractBiological reactions are mostly concerned with selective interactions between small ligands and macromolecular receptors. The same ligands may activate responses of different intensities and/or effects in the presence of different receptors. Many approaches based on spectroscopic and non‐spectroscopic methods have been used to study interactions between small ligands and macromolecular receptors, including methods based on NMR and IR spectroscopic analysis of the solution behaviour of the ligand in the presence of receptors. In this work, we investigated the interaction between ovine serum albumin with two amphenicolic antibiotics [chloramphenicol (CAP) and thiamphenicol (TAP)], using a combined approach based on NMR and IR methodologies, furnishing complementary information about the recognition process occurring within the two systems. The two ligands, despite their similar structures, showed different affinities towards albumin. NMR methodology is based on the comparison of selective ($R_{1}^{SE}$) and non‐selective ($R_{1}^{NS}$) spin–lattice relaxation rates of the ligands in the presence and absence of macromolecular receptors and$R_{1}^{NS}$and$R_{1}^{SE}$temperature dependence analysis. From these studies, the ligand–receptor binding strength was evaluated on the basis of the ‘affinity index.’ The derivation of the affinity index from chemical equilibrium kinetics for both the CAP–albumin and TAP–albumin systems allowed a comparison of the abilities of the two amphenicolic antibiotics to interact with the protein. IR methodology is based on the comparison of the ligand–protein ‘complex’ spectra with those of the non‐interacting systems. On the basis of the differences revealed, a more thorough IR analysis was performed in order to understand the structural changes which occurred on both ligand and protein molecules within the interacting system. Copyright © 2003 John Wiley & Sons, Ltd.
Conformational analysis of trinucleotides containing a single abasic residue; mimics of DNA damage
Authors: Baker John M. , Arnold John R. P. , Fisher Julie 
Published: June 2003

AbstractThe conformations of three deoxytrinucleotide analogues [d(TpXpT), where X = T, tetrahydrofuran (THF) or propyl (Pr)] were investigated using 1H NMR spectroscopy as part of our studies of DNA‐base damage. The phosphorus‐decoupled 1H NMR spectrum of each compound was simulated and values for the vicinal proton–proton coupling constants of the sugar ring hydrogens were extracted at several different temperatures, for use in conformational analyses. It was found that the south‐pucker preference of the sugar 3′ to the modification is increased whereas that of the 5′ is decreased relative to the puckers observed for the non‐modified system. The conformational change is <25%. This subtle effect may be sufficient for recognition by DNA repair enzymes. Copyright © 2003 John Wiley & Sons, Ltd.
1H, 13C and 15N NMR investigation of a new, condensed hexahydro‐1,3,5‐triazine
Authors: Simon A. , Tóth G. , Librera C. P. , Adam W. 
Published: June 2003

AbstractTreatment of 2‐acetyl‐2‐methylcyclopentanone with hydrazine hydrate yielded a new condensed hexahydro‐1,3,5‐triazine (3b), which is the first example of the ketimine‐type trimers. A complete 1H, 13C and 15N NMR assignment of the compound was achieved. Copyright © 2003 John Wiley & Sons, Ltd.
Flow injection analysis NMR (FIA–NMR): a novel flow NMR technique that complements LC–NMR and direct injection NMR (DI–NMR)
Authors: Keifer Paul A. 
Published: June 2003

AbstractDetails of a new flow NMR technique, flow injection analysis NMR (FIA–NMR), are presented for the first time. This method blends some aspects of both liquid chromatography–NMR and direct injection NMR, and complements both. FIA‐NMR is shown to be useful as an analytical technique, especially for repetitive analyses, and may also prove useful in the analysis of combinatorial chemistry libraries. The feasibility of FIA‐NMR is demonstrated by the quantitative analysis of an over‐the‐counter pharmaceutical. Copyright © 2003 John Wiley & Sons, Ltd.