bluuebunny/crossref_metadata_2025 huggingface dataset:
Testing the purchasing power parity through I(2) cointegration techniques
Authors: Bacchiocchi Emanuele , Fanelli Luca
Published: June 2005

This paper contributes to the empirical literature on the purchasing power parity (PPP) over the post‐Bretton Woods period by providing a time‐series based interpretation of the controversial evidence characterizing the dynamics of real exchange rates. It is shown that the persistence of deviations from the PPP between a set of European countries and the United States may be empirically attributed to the presence of I(2) stochastic trends in prices using Consumer Price Indices. Interestingly, the slow adjustment towards the equilibrium can be modelled through ‘integral‐proportional’ equilibrium correction models and this evidence can be partly reconciled with theories where the inflation rate reduces the markup of profit‐maximizing firms acting on imperfectly competitive markets. Copyright © 2005 John Wiley & Sons, Ltd.
Radiation synthesis of poly(N‐vinyl‐2‐pyrrolidone)–κ‐carrageenan hydrogels and their use in wound dressing applications. I. Preliminary laboratory tests
Authors: Şen Murat , Avcı Esra Nazan
Published: June 2005

Poly(N‐vinyl‐2‐pyrrolidone)–κ‐carrageenan hydrogels (PVP‐KC) were prepared by irradiating the mixtures of aqueous solutions of PVP, KC, potassium chloride, and poly(ethylene glycol) by γ‐rays at different doses. Their preliminary laboratory tests were evaluated to identify their usability in wound dressing applications. For investigation of the effect of components on the gelation of PVP, sol–gel analyses were made and gel fractions of the hydrogels were determined. Mechanical experiments were conducted for both unirradiated and irradiated samples. For investigation of the fluid uptake capacity of the hydrogels, swelling experiments were performed in pseudo‐extracellular fluid solution at various temperatures. Acidity/alkalinity (pH) and electrical conductivity tests were achieved from aqueous extracts of hydrogels, and bioadhesion strength of the hydrogels was investigated on human skin. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Improving the blood compatibility of polyurethane using carbon nanotubes as fillers and its implications to cardiovascular surgery
Authors: Meng J. , Kong H. , Xu H. Y. , Song L. , Wang C. Y. , Xie S. S.
Published: June 2005

Blood compatibility has been an occlusion for biomaterials used in the cardiovascular system. In this work, a multiwalled carbon nanotubes‐polyurethane composite (MWNT‐PU) was prepared through a controlled co‐precipitation. The surface chemical composition of treated carbon nanotubes was analyzed with XPS and the thermal behaviors of composite were characterized by DSC. The platelet adhesion and activation caused by the composite were evaluated by using SEM and flow cytometric analysis, respectively, and the disruption of red blood cells was analyzed through measuring the absorbance of free hemoglobin. The experimental results demonstrated that: (1) Multiwalled carbon nanotubes (MWNTs) with oxygen‐containing functional groups could be well dispersed in polyurethane matrix through a controlled coprecipitation; (2) the composite surface displayed a significantly improved anticoagulant function, which can be indicative of the promising potentials of carbon nanotube‐based materials in the implants and medical devices applied in blood‐contacting environments. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Effects of nano HAP on biological and structural properties of glass bone cement
Authors: Fu Qiang , Zhou Nai , Huang Wenhai , Wang Deping , Zhang Liying , Li Haifeng
Published: June 2005

A novel type of glass‐based nanoscale hydroxyapatite (HAP) bioactive bone cement (designed as GBNHAPC) was synthesized by adding nanoscale hydroxyapatite crystalline (20–40 nm), into the self‐setting glass‐based bone cement (GBC). The inhibition rate of nanoscale HAP and micron HAP on osteosarcoma U2‐OS cells was examined. The effects of nanoscale HAP on the crystal phase, microstructure and compressive strength of GBNHAPC were studied, respectively. It was concluded that nanoscale HAP could inhibit the cell proliferation, whereas micron HAP could not, and that nanoscale HAP could be dispersed in the cement evenly and the morphology did not change significantly after a longer immersion time. XRD and FTIR results show nanoscale HAP did not affect the setting reaction of the cement. Furthermore, GBNHAPC had a higher compressive strength (92.6 ± 3.8 MPa) than GBC (80.1 ± 3.0 MPa). It was believed that GBNHAPC might be a desirable biomaterial that could not only fill bone defects but also inhibit cancer cell growth. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
A novel osteotropic biomaterial OG‐PLG: In vitro efficacy
Authors: Whang Kyumin , Grageda Edgar , Khan Ambereen , McDonald Jonathan , Lawton Mark , Satsangi Neera
Published: June 2005

Previously, a novel osteotropic biomaterial, OG‐PLG [simvastatin grafted to poly(lactide‐co‐glycolide), PLG], was synthesized and shown to have degradation‐controlled release kinetics. The objective here was to determine the effect of grafting statins to PLG on bone regeneration in vitro. Rat bone marrow cells were stimulated in vitro with simvastatin dissolved in media, saponified simvastatin dissolved in media, simvastatin released through diffusion from emulsion freeze‐dried scaffolds, and OG‐PLG. Unstimulated cultures and cultures stimulated with dexamethasone were used as negative and positive controls, respectively. In vitro bone formation was assessed using the alkaline phosphatase (ALP) and von Kossa assays at different times up to 16 days. ALP analysis revealed that saponified simvastatin at 10−7M and OG‐PLG significantly increased ALP expression at various time points. von Kossa assay showed that simvastatin, saponified simvastatin, and OG‐PLG significantly enhanced mineralization, with the effect from OG‐PLG being the most significant. In short, OG‐PLG significantly enhanced in vitro bone cell mineralization beyond the effect of simvastatin or saponified simvastatin dissolved in media and simvastatin released via diffusion from scaffolds. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Arsenic trioxide (As2O3) inhibits invasion of HT1080 human fibrosarcoma cells: Role of nuclear factor‐κB and reactive oxygen species
Authors: Park Myung‐Jin , Lee Jae‐Young , Kwak Hee‐Jin , Park Chang‐Min , Lee Hyung‐Chahn , Woo Sang Hyeok , Jin Hyun‐Ok , Han Chul‐Ju , An Sungkwan , Lee Seung‐Hoon , Chung Hee Yong , Park In‐Chul , Hong Seok‐Il , Rhee Chang Hun
Published: June 2005

In order to define the role of As2O3 in regulating the tumor cell invasiveness, the effects of As2O3 on secretion of matrix metalloproteinases (MMPs) and urokinase plasminogen activator (uPA), and in vitro invasion of HT1080 human fibrosarcoma cells were examined. As2O3 inhibited cell adhesion to the collagen matrix in a concentration dependent manner, whereas the same treatment enhanced cell to cell interaction. In addition, As2O3 inhibited migration and invasion of HT1080 cells stimulated with phorbol 12‐myristate 13‐aceate (PMA), and suppressed the expression of MMP‐2, ‐9, membrane type‐1 MMP, uPA, and uPA receptor (uPAR). In contrast, As2O3 increased the expression of tissue inhibitor of metalloproteinase (TIMP)‐1 and PA inhibitor (PAI)‐1, and reduced the MMP‐2, ‐9, and uPA promoter activity in the presence and absence of PMA. Furthermore, the promoter stimulating and DNA binding activity of nuclear factor‐κB (NF‐κB) was blocked by As2O3, whereas the activator protein‐1 activity was unchanged. Pretreatment of the cells with N‐acetyl‐L‐cysteine (NAC) significantly prevented suppression of MMPs and uPA secretion, DNA binding activity of NF‐κB, and in vitro invasion of HT1080 cells by As2O3, suggesting a role of reactive oxygen species (ROS) in this process. These results suggest that As2O3 inhibits tumor cell invasion by modulating the MMPs/TIMPs and uPA/uPAR/PAI systems of extracellular matrix (ECM) degradation. In addition, the generation of ROS and subsequent suppression of NF‐κB activity by As2O3 might partly be responsible for the phenomena. Overall, As2O3 shows potent activity controlling tumor cell invasiveness in vitro. © 2005 Wiley‐Liss, Inc.
Compartmentalization of hnRNP‐K during cell cycle progression and its interaction with calponin in the cytoplasm
Authors: Laury‐Kleintop Lisa D. , Tresini Maria , Hammond Olivia
Published: June 2005

Coronary artery blockage, due to cardiovascular disease, is routinely treated by either balloon‐angioplasty or bypass surgery. The limited success of these clinical interventions is due at least in part to smooth muscle cell (SMC) proliferation. Here we show that heterogeneous nuclear ribonucleoprotein complex K (hnRNP‐K) protein levels increase in SMC with response to serum stimulation in vitro, in the aortas from an animal model of atherosclerosis, and in occluded human vein segments. hnRNP‐K is a multi‐functional protein that has been studied primarily in cancer cells and has been suggested to play a role in cell cycle progression. We show that in untransformed, cultured SMC, hnRNP‐K protein sub‐cellular localization modulates through the cell cycle in both the cytoplasm and nucleus. Using cycloheximide, we observed that cytoplasmic accumulation of hnRNP‐K protein at later time points in the cell cycle occurred with a concomitant decrease in nuclear hnRNP‐K protein, suggesting a translocation of nuclear hnRNP‐K protein to the cytoplasm. Also, because we did not observe an increase in hnRNP‐K protein at early time points in the cell cycle in the presence of cycloheximide, we propose that the early increase in cytoplasmic hnRNP‐K protein following serum stimulation is due to new hnRNP‐K protein synthesis. When present in the cytoplasm, hnRNP‐K is part of a multi‐protein complex that consists of at least two other proteins, calponin and ERK1/2. Our findings from this study are intriguing because they suggest that cytoplasmic hnRNP‐K in SMC is part of a signaling complex that may be involved in growth‐stimulated post‐transcriptional regulation. © 2005 Wiley‐Liss, Inc.
Overexpression of regucalcin suppresses cell proliferation in cloned rat hepatoma H4‐II‐E cells: Involvement of intracellular signaling factors and cell cycle‐related genes
Authors: Yamaguchi Masayoshi , Daimon Yuko
Published: June 2005

The role of regucalcin, which is a regulatory protein in intracellular signaling pathway, in the regulation of cell proliferation was investigated by using the cloned rat hepatoma H4‐II‐E cells overexpressing regucalcin. The hepatoma cells (wild type) and stable regucalcin/pCXN2 transfectants were cultured for 72 h in a medium containing 10% fetal bovine serum (FBS) to obtain subconfluent monolayters. The proliferation of cells was significantly suppressed in transfectants cultured for 24–72 h. The proliferation of wild‐type cells was significantly inhibited when the cells were cultured for 72 h in a medium containing an inhibitor of transcriptional activity or protein synthesis. Such an effect was not seen in transfectants. The presence of various inhibitors of protein kinase including PD 98059 (10−7 or 10−6 M), dibucaine (10−6 M), wortmannin (10−8 or 10−6 M), or genistein (10−5 M) caused a significant inhibition of the proliferation of wild‐type cells. These inhibitory effects were not seen in transfectants. Staurosporine (10−8 − 10−7 M) significantly inhibited the proliferation of wild‐type cells and transfectants. Also, the effect of vanadate (10−5 M), an inhibitor of protein tyrosine phosphatase, or Bay K 8644 (10−6 M), an agonist of calcium entry into cells, in inhibiting the proliferation of wild‐type cells was not observed in transfectants. Moreover, the proliferation of wild‐type cells was significantly inhibited in the presence of roscovitine (10−7 or 10−6 M) or sulforaphane (10−7 M), which induces cell‐cycle arrest. Such effect was not seen in transfectants. The inhibitory effect of sodium butyrate (8.3 × 10−4 M) on proliferation of wild‐type cells was also induced in transfectants. Gene expression in hepatoma cells cultured for 72 h with 10% FBS was determined by using reverse transcription‐polymerase chain reaction (RT‐PCR). The expression of p21 mRNA was significantly enhanced in transfectants, while cdc2a and chk2 mRNA expression were not significantly changed. Insulin‐like growth factor‐I (IGF‐I) mRNA expression was significantly suppressed in transfectants. This study demonstrates that overexpression of regucalcin has a suppressive effect on cell proliferation that is partly mediated through various intracellular signaling‐related factors, and that the effect may be partly involved in the change in p21 or IGF‐I mRNA expression. The finding further supports that regucalcin plays an important role as a suppressor in the enhancement of cell proliferation. © 2005 Wiley‐Liss, Inc.
Methionine aminopeptidases type I and type II are essential to control cell proliferation
Authors: Bernier Sylvie G. , Taghizadeh Nazbeh , Thompson Charles D. , Westlin William F. , Hannig Gerhard
Published: June 2005

The dependence of cell growth on methionine aminopeptidase (MetAP) function in bacteria and yeast is firmly established. Here we report experimental evidence that the control of cell proliferation in mammalian cells is directly linked and strictly dependent on the activity of both MetAP‐1 and MetAP‐2. The targeted downregulation of either methionine aminopeptidase MetAP‐1 or MetAP‐2 protein expression by small interfering RNA (siRNA) significantly inhibited the proliferation of human umbilical vein endothelial cells (HUVEC) (70%–80%), while A549 human lung carcinoma cell proliferation was less inhibited (20%–30%). The cellular levels of MetAP‐2 enzyme were measured after MetAP‐2 siRNA treatment and found to decrease over time from 4 to 96 h, while rapid and complete depletion of MetAP‐2 enzyme activity was observed after 4 h treatment with two pharmacological inhibitors of MetAP‐2, PPI‐2458 and fumagillin. When HUVEC and A549 cells were treated simultaneously with MetAP‐2 siRNA and PPI‐2458, or fumagillin, which irreversibly inhibit MetAP‐2 enzyme activity, no additive effect on maximum growth inhibition was observed. This strongly suggests that MetAP‐2 is the single critical cellular enzyme affected by either MetAP‐2 targeting approach. Most strikingly, despite their significantly different sensitivity to growth inhibition after targeting of either MetAP‐1 or MetAP‐2, HUVEC, and A549 cells, which were made functionally deficient in both MetAP‐1 and MetAP‐2 were completely or almost completely inhibited in their growth, respectively. This closely resembled the observed growth inhibition in genetically double‐deficient map1map2 yeast strains. These results suggest that MetAP‐1 and MetAP‐2 have essential functions in the control of mammalian cell proliferation and that MetAP‐dependent growth control is evolutionarily highly conserved. © 2005 Wiley‐Liss, Inc.
Myosin light chain kinase and acto‐myosin contractility modulate activation of the ERK cascade downstream of oncogenic Ras
Authors: Helfman David M. , Pawlak Geraldine
Published: June 2005

The actin cytoskeleton is recognized as an important component of both adhesion‐ and growth factor‐dependent signaling, but its role in oncogene‐dependent signaling has received much less attention. In this study, we investigated the role played by the acto‐myosin cytoskeleton and its main regulators, i.e., myosin light chain kinase and Rho kinase, in oncogenic Ki‐Ras‐induced signaling. We found that activation of the ERK cascade by Ras is dependent on acto‐myosin contractility, under the regulation of myosin light chain kinase but not Rho kinase. Inhibition of myosin II or myosin light chain kinase caused a complete loss of ERK phosphorylation in a time‐ and dose‐dependent manner, but proved dispensable for activation of the PI3K pathway. We also provide evidence that the target of myosin light chain kinase lays at the level of Raf activation. Since myosin light chain kinase is a target of ERK, these results suggest a previously uncharacterized signaling pathway involving Ras‐mediated alterations of the actin cytoskeleton, which might play a critical role in ERK activation by the Ras oncogene and contribute to aberrant signaling and enhanced cell motility. In addition, restoration of stress fibers following ectopic expression of tropomyosin 2 resulted in reduced levels of ERK phosphorylation. Finally, these studies suggest that myosin light chain kinase but not Rho kinase plays an essential role in the generation of ERK signaling in transformed cells and indicate distinct cellular roles for Rho‐kinase and myosin light chain kinase‐dependent functions involving the regulation of acto‐myosin contractility. © 2005 Wiley‐Liss, Inc.
Role of c‐Jun N‐terminal kinase in the PDGF‐induced proliferation and migration of human adipose tissue‐derived mesenchymal stem cells
Authors: Kang Yong Jung , Jeon Eun Su , Song Hae Young , Woo Jae Suk , Jung Jin Sup , Kim Yong Keun , Kim Jae Ho
Published: June 2005

Platelet‐derived growth factor (PDGF) is a critical regulator of proliferation and migration for mesenchymal type cells. In this study, we examined the role of mitogen‐activated protein (MAP) kinases in the PDGF‐BB‐induced proliferation and migration of human adipose tissue‐derived mesenchymal stem cells (hATSCs). The PDGF‐induced proliferation was prevented by a pretreatment with the c‐Jun N‐terminal kinase (JNK) inhibitor, SP600125. However, it was not prevented by a pretreatment with a p38 MAP kinase inhibitor, SB202190, and a specific inhibitor of the upstream kinase of extracellular signal‐regulated kinase (ERK1/2), U0126. Treatment with PDGF induced the activation of JNK and ERK in hATSCs, and pretreatment with SP600125 specifically inhibited the PDGF‐induced activation of JNK. Treatment with PDGF induced the cell cycle transition from the G0/G1 phase to the S phase, the elevated expression of cyclin D1, and the phosphorylation of Rb, which were prevented by a pretreatment with SP600125. In addition, the PDGF‐induced migration of hATSCs was completely blocked by a pretreatment with SP600125, but not with U0126 and SB202190. These results suggest that JNK protein kinase plays a key role in the PDGF‐induced proliferation and migration of mesenchymal stem cells. © 2005 Wiley‐Liss, Inc.
FRNK, the autonomously expressed C‐terminal region of focal adhesion kinase, is uniquely regulated in vascular smooth muscle: Analysis of expression in transgenic mice
Authors: Hayasaka Haruko , Simon Kate , Hershey E. Daniel , Masumoto Koh‐hei , Parsons J. Thomas
Published: June 2005

FRNK, the autonomously expressed carboxyl‐terminal region of focal adhesion kinase (FAK), is expressed in tissues that are rich in vascular smooth muscle cells (VSMCs). Here we report the generation of transgenic mice harboring the putative FRNK promoter fused to LacZ and examine the promoter activity in situ via expression of β‐galactosidase. The transgenic mice exhibited expression of β‐galactosidase predominantly in arterial VSMCs in large and small blood vessels of major organs. Upregulation of β‐galactosidase activity was observed in tunica media following carotid injury, indicating that the FRNK promoter is activated in VSMCs in response to injury. Robust expression of β‐galactosidase in blood vessels was also detected in the developing embryo. However, expression was also observed in the midline, the nose and skin epidermis, indicating distinct transcriptional regulation of the FRNK promoter in embryogenesis. To analyze FRNK expression in vitro, we identified a 116 bp sequence in the FRNK promoter that was sufficient to function as an enhancer when fused to the minimal actin promoter and expressed in cultured smooth muscle cells. Mutation of AP‐1 and NF‐E2 binding consensus sequences within this element abrogated enhancer activity, supporting the involvement of this promoter element in VSMC expression of FRNK. © 2005 Wiley‐Liss, Inc.
Virtual reality of stem cell transplantation to repair injured myocardium
Authors: Lum Lawrence G. , Padbury James F. , Davol Pamela A. , Lee Randall J.
Published: June 2005

The search for the fountain of youth continues into the 21st century with hopes that embryonic or hematopoietic stem cells (SC) will repair injured tissues in the heart, lungs, pancreas, muscles, nerves, liver, or skin. This commentary focuses on the potential of SC for inducing cardiac regeneration after myocardial injury, the barriers to SC treatment that need to be overcome for ensuring successful cardiac repair, and the experimental approaches that can be applied to the problem. © 2005 Wiley‐Liss, Inc.
PDGF‐BB induces vascular smooth muscle cell expression of high molecular weight FGF‐2, which accumulates in the nucleus
Authors: Pintucci Giuseppe , Yu Pey‐Jen , Saponara Fiorella , Kadian‐Dodov Daniella L. , Galloway Aubrey C. , Mignatti Paolo
Published: June 2005

Basic fibroblast growth factor (FGF‐2) and platelet‐derived growth factor (PDGF) are implicated in vascular remodeling secondary to injury. Both growth factors control vascular endothelial and smooth muscle cell proliferation, migration, and survival through overlapping intracellular signaling pathways. In vascular smooth muscle cells PDGF‐BB induces FGF‐2 expression. However, the effect of PDGF on the different forms of FGF‐2 has not been elucidated. Here, we report that treatment of vascular aortic smooth muscle cells with PDGF‐BB rapidly induces expression of 20.5 and 21 kDa, high molecular weight (HMW) FGF‐2 that accumulates in the nucleus and nucleolus. Conversely, PDGF treatment has little or no effect on 18 kDa, low‐molecular weight FGF‐2 expression. PDGF‐BB‐induced upregulation of HMW FGF‐2 expression is controlled by sustained activation of extracellular signal‐regulated kinase (ERK)‐1/2 and is abolished by actinomycin D. These data describe a novel interaction between PDGF‐BB and FGF‐2, and indicate that the nuclear forms of FGF‐2 may mediate the effect of PDGF activity on vascular smooth muscle cells. © 2005 Wiley‐Liss, Inc.
Adaptation of a fast Fourier transform‐based docking algorithm for protein design
Authors: Huang Po‐Ssu , Love John J. , Mayo Stephen L.
Published: June 2005

Designing proteins with novel protein/protein binding properties can be achieved by combining the tools that have been developed independently for protein docking and protein design. We describe here the sequence‐independent generation of protein dimer orientations by protein docking for use as scaffolds in protein sequence design algorithms. To dock monomers into sequence‐independent dimer conformations, we use a reduced representation in which the side chains are approximated by spheres with atomic radii derived from known C2 symmetry‐related homodimers. The interfaces of C2‐related homodimers are usually more hydrophobic and protein core‐like than the interfaces of heterodimers; we parameterize the radii for docking against this feature to capture and recreate the spatial characteristics of a hydrophobic interface. A fast Fourier transform‐based geometric recognition algorithm is used for docking the reduced representation protein models. The resulting docking algorithm successfully predicted the wild‐type homodimer orientations in 65 out of 121 dimer test cases. The success rate increases to ∼70% for the subset of molecules with large surface area burial in the interface relative to their chain length. Forty‐five of the predictions exhibited less than 1 Å Cα RMSD compared to the native X‐ray structures. The reduced protein representation therefore appears to be a reasonable approximation and can be used to position protein backbones in plausible orientations for homodimer design. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1222–1232, 2005
Conformations, energies, and intramolecular hydrogen bonds in dicarboxylic acids: Implications for the design of synthetic dicarboxylic acid receptors
Authors: Nguyen Thanh Ha , Hibbs David E. , Howard Siân T.
Published: June 2005

The various conformers of the dicarboxylic acids HO2C(CH2)nCO2H, n = 1–4, were obtained using density functional methods (DFT), both in the gas phase and in the aqueous phase using a polarized continuum model (PCM). Several new conformers were identified, particularly for the two larger molecules glutaric (n = 3) and adipic acid (n =4). The PCM results show that the stability of most conformers were affected, many becoming unstable in the aqueous phase; and the energy ordering of conformers is also different. The results suggest that conformational preferences could be important in determining the design and stability of appropriate synthetic receptors for glutaric and adipic acid. Geometry changes between gas and aqueous phases were most marked in those conformers containing an intramolecular hydrogen bond. Additional calculations have probed the strength of intramolecular hydrogen bonds in these dicarboxylic acids. In the cases of glutaric and adipic acid, the strength of the intramolecular hydrogen bond were estimated to be around 28–29 kJ/mol, without any vibrational energy correction. The intramolecular hydrogen bond energies in malonic and succinic acid were also estimated from the calculated H‐bond distances using an empirical relationship. Intramolecular H‐bond redshifts of 170–250 cm−1 have been estimated from the results of the harmonic frequency analyses. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1233–1241, 2005
Optimization of auxiliary basis sets for the LEDO expansion and a projection technique for LEDO–DFT
Authors: Götz Andreas W. , Kollmar Christian , Hess Bernd A.
Published: June 2005

We present a systematic procedure for the optimization of the expansion basis for the limited expansion of diatomic overlap density functional theory (LEDO‐DFT) and report on optimized auxiliary orbitals for the Ahlrichs split valence plus polarization basis set (SVP) for the elements H, LiF, and NaCl. A new method to deal with near‐linear dependences in the LEDO expansion basis is introduced, which greatly reduces the computational effort of LEDO–DFT calculations. Numerical results for a test set of small molecules demonstrate the accuracy of electronic energies, structural parameters, dipole moments, and harmonic frequencies. For larger molecular systems the numerical errors introduced by the LEDO approximation can lead to an uncontrollable behavior of the self‐consistent field (SCF) process. A projection technique suggested by Löwdin is presented in the framework of LEDO–DFT, which guarantees for SCF convergence. Numerical results on some critical test molecules suggest the general applicability of the auxiliary orbitals presented in combination with this projection technique. Timing results indicate that LEDO–DFT is competitive with conventional density fitting methods. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1242–1253, 2005
Linear Ramsey numbers of sparse graphs
Authors: Shi Lingsheng
Published: June 2005

The Ramsey number R(G1,G2) of two graphs G1 and G2 is the least integer p so that either a graph G of order p contains a copy of G1 or its complement Gc contains a copy of G2. In 1973, Burr and Erdős offered a total of $25 for settling the conjecture that there is a constant c = c(d) so that R(G,G)≤ c|V(G)| for all d‐degenerate graphs G, i.e., the Ramsey numbers grow linearly for d‐degenerate graphs. We show in this paper that the Ramsey numbers grow linearly for degenerate graphs versus some sparser graphs, arrangeable graphs, and crowns for example. This implies that the Ramsey numbers grow linearly for degenerate graphs versus graphs with bounded maximum degree, planar graphs, or graphs without containing any topological minor of a fixed clique, etc. © 2005 Wiley Periodicals, Inc. J Graph Theory
The number of pancyclic arcs in a k‐strong tournament
Authors: Yeo Anders
Published: June 2005

A tournament is a digraph, where there is precisely one arc between every pair of distinct vertices. An arc is pancyclic in a digraph D, if it belongs to a cycle of length l, for all 3 ≤ l ≤ |V (D) |. Let p(D) denote the number of pancyclic arcs in a digraph D and let h(D) denote the maximum number of pancyclic arcs belonging to the same Hamilton cycle of D. Note that p(D) ≥ h(D). Moon showed that h(T) ≥ 3 for all strong non‐trivial tournaments, T, and Havet showed that h(T) ≥ 5 for all 2‐strong tournaments T. We will show that if T is a k‐strong tournament, with k ≥ 2, then p(T)  ≥ 1/2, nk and h(T) ≥ (k + 5)/2. This solves a conjecture by Havet, stating that there exists a constant αk, such that p(T) ≥ αk n, for all k‐strong tournaments, T, with k ≥ 2. Furthermore, the second results gives support for the conjecture h(T) ≥ 2k + 1, which was also stated by Havet. The previously best‐known bounds when k ≥ 2 were p(T) ≥ 2k + 3 and h(T) ≥ 5. © 2005 Wiley Periodicals, Inc. J Graph Theory
Re‐dating of Chinese celadon shards excavated on Mapungubwe Hill, a 13thcentury Iron Age site in South Africa, using Raman spectroscopy, XRF and XRD
Authors: Prinsloo Linda C. , Wood Nigel , Loubser Maggi , Verryn Sabine M. C. , Tiley Sian
Published: June 2005

Chinese celadon shards of the Longquan type, believed to date from the Southern Song dynasty (1127–1279AD), were excavated in 1934 on Mapungubwe Hill, a 13th century Iron Age site in the Limpopo valley, South Africa. We studied the shards with Raman spectroscopy, x‐ray fluorescence (XRF) spectroscopy and x‐ray diffraction (XRD). The Raman polymerization index (Ip), calculated from the spectra of the glaze of the shards, indicated a higher firing temperature than expected for the relatively calcium‐rich Longquan glazes of the Southern Song dynasty. XRF analysis of the glaze and XRD measurements of the bulk of the shards supported this view and date the shards to possibly the Yuan (1279–1368AD) or even early Ming (1368–1644AD) dynasties. These results have an impact on the chronology of the history of the region and therefore call for further research of a comparative nature of other Chinese celadon shards excavated on archaeological sites in Africa, in addition to additional carbon dates of Mapungubwe hill. Copyright © 2005 John Wiley & Sons, Ltd.
Basic scheduling problems with raw material constraints
Authors: Grigoriev Alexander , Holthuijsen Martijn , van de Klundert Joris
Published: June 2005

One of the achievements of scheduling theory is its contribution to practical applications in industrial settings. In particular, taking finiteness of the available production capacity explicitly into account, has been a major improvement of standard practice. Availability of raw materials, however, which is another important constraint in practice, has been largely disregarded in scheduling theory. This paper considers basic models for scheduling problems in contemporary manufacturing settings where raw material availability is of critical importance. We explore single scheduling machine problems, mostly with unit or all equal processing times, and Lmax and Cmax objectives. We present polynomial time algorithms, complexity and approximation results, and computational experiments. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.
Metabolic differences between primary and recurrent human brain tumors: a 1H NMR spectroscopic investigation
Authors: Lehnhardt Fritz‐Georg , Bock Christian , Röhn Gabriele , Ernestus Ralf‐Ingo , Hoehn Mathias
Published: June 2005

High‐resolution proton magnetic resonance spectroscopy was performed on tissue specimens from 33 patients with astrocytic tumors (22 astrocytomas, 11 glioblastomas) and 13 patients with meningiomas. For all patients, samples of primary tumors and their first recurrences were examined. Increased anaplasia, with respect to malignant transformation, resulting in a higher malignancy grade, was present in 11 recurrences of 22 astrocytoma patients. Spectroscopic features of tumor types, as determined on samples of the primary occurrences, were in good agreement with previous studies. Compared with the respective primary astrocytomas, characteristic features of glioblastomas were significantly increased concentrations of alanine (Ala) (p = 0.005), increased metabolite ratios of glycine (Gly)/total creatine (tCr) (p = 0.0001) and glutamate (Glu)/glutamine (Gln) (p = 0.004). Meningiomas showed increased Ala (p = 0.02) and metabolite ratios [Gly, total choline (tCho), Ala] over tCr (p = 0.001) relative to astrocytomas, and N‐acetylaspartate and myo‐inositol were absent. Metabolic changes of an evolving tumor were observed in recurrent astrocytomas: owing to their consecutive assessments, more indicators of malignant degeneration were detected in astrocytoma recurrences (e.g. Gly, p = 0.029; tCho, p = 0.034; Glu, p = 0.015; tCho/tCr, p = 0.001) in contrast to the comparison of primary astrocytomas with primary glioblastomas. The present investigation demonstrated a correlation of the tCho‐signal with tumor progression. Significantly elevated concentrations of Ala (p = 0.037) and Glu (p = 0.003) and metabolite ratio tCho/tCr (p = 0.005) were even found in recurrent low‐grade astrocytomas with unchanged histopathological grading (n = 11). This may be related to an early stage of malignant transformation, not yet detectable morphologically, and emphasizes the high sensitivity of 1H NMR spectroscopy in elucidating characteristics of brain tumor metabolism. Copyright © 2005 John Wiley & Sons, Ltd.
Intraobserver and interobserver reproducibility of three‐dimensional gray‐scale and power Doppler ultrasound examinations of the cervix in pregnant women
Authors: Rovas L. , Sladkevicius P. , Strobel E. , Valentin L.
Published: June 2005

Objectives

To determine intraobserver and interobserver reproducibility of three‐dimensional (3D) gray‐scale and power Doppler ultrasound examinations of the cervix in pregnant women.

Methods

Thirty‐two pregnant women underwent transvaginal 3D gray‐scale and power Doppler ultrasound examination of the cervix by two examiners. Each observer acquired two volumes, and they each analyzed their volumes twice using the commercially available software Virtual Organ Computer‐aided AnaLysis (VOCAL™). The variables analyzed were cervical volume (cm3), vascularization index (VI), flow index (FI) and vascularization flow index (VFI). Intraobserver repeatability was expressed as the difference between two measurement results (mean difference ± 2 SD, i.e. limits of agreement) and as intraclass correlation coefficient (intra‐CC). Interobserver agreement was expressed as the difference between the results of the two observers (limits of agreement) and as interclass correlation coefficient (inter‐CC). The contribution of various factors (examiner, acquisition, analysis of acquired volume) to intrasubject variance was estimated using different analysis of variance models. All statistical analyses were performed using log‐transformed data. The results presented are those obtained after antilogarithmic transformation, i.e. the results are presented as ratios between two results of the same observer, or as ratios between the results of Observer 1 and Observer 2.

Results

All intraobserver and interobserver log‐transformed differences were normally distributed. There was no systematic bias between the two observers. Both intra‐ and inter‐CC values were high (0.93–0.98) for all variables except FI (0.63–0.88), despite the limits of agreement being wide, especially for VI (widest range 0.4–2.4) and VFI (widest range 0.3–2.6). Acquisition explained most of the intrasubject variance of the flow indices, the contribution of examiner and analysis being unimportant.

Conclusions

Given the wide range between the lower and upper limits of agreement, it would probably not be possible to detect anything but large differences or changes in cervical volume or cervical flow indices using current 3D ultrasound techniques. Because acquisition explained most of the intrasubject variance, the average of several repeated acquisitions should be used to enhance reproducibility. However, it is not worth doing more than one analysis of an acquired volume, because the effect of analysis on measurement results is small. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
A cross‐layer cost‐function based rate adaptation mechanism for the WCDMA system with multi‐class services by transport format selection
Authors: Wang Li‐Chun , Chen Ming‐Chi , Chen Yi‐Cheng
Published: June 2005

The growing demand of high speed multi‐class data transmissions poses new challenges on wireless networks. The major objectives of the next generation wireless networks include: (1) achieving high data throughput in the fast varying wireless channel; (2) transmitting multi‐class data by service multiplexing; and (3) controlling the delay for delay sensitive service. To achieve these goals, in the context of wideband code division multiple access (WCDMA) system, we propose a cost‐function based rate adaptation mechanism by taking account of both physical layer channel impacts and higher layer performance parameters, such as buffer occupancy and service priority. We implement this cross‐layer rate mechanism by exploiting the transport format (TF) selection procedure in the medium access control (MAC) layer of the WCDMA system. Through the proposed cross‐layer cost function, the TF selection procedure can dynamically adapt suitable spreading factors every transmission time interval (TTI), usually 10–80 ms. Through simulations in a flat Rayleigh fading channel, we show that the proposed cross‐layer cost‐function based rate adaptation mechanism can effectively improve throughput and reduce the buffer occupancy for multi‐class services for the WCDMA system at the cost of slightly higher power efficiency. Copyright © 2005 John Wiley & Sons, Ltd.
Color‐aware power and rate adaptation in IP‐based CDMA radio access networks
Authors: Friderikos V. , Wang L. , Iwamura M. , Aghvami A. H.
Published: June 2005

With IP technology being in the epicenter of future wireless networks, IP‐centric resource management is currently receiving an increasing research attention. In this paper, a power and rate adaptation semantic is proposed that integrates quality of service (QoS) information from the IP layer of the differentiated services (DiffServ) architecture together with lower layer criteria in order to optimize packet transmission over the wireless interface. An optimization problem is formulated based on the output of a time sliding window three color marker (TSWtcm) of the ingress DiffServ node in the radio access network (RAN), where color aware power and rate control are performed. The critical impetus of the proposed approach besides minimization of the transmitted power is mainly twofold. Firstly, to achieve the required per‐class aggregate data rate, while prioritizing and ensuring QoS of in‐profile packets and secondly, to increase aggregate power gains by penalizing out‐of‐profile packets. The seminal aspect of the proposed scheme is that tangible power gains can be achieved by differentiating transmission of conformant and non‐conformant packets while at the same time the power gains within each AF classes can be utilized to enhance the performance of in‐profile traffic. To buttress the case, both theoretical and simulation results are meticulously presented that depict architectural and performance related aspects of the proposed scheme. Copyright © 2005 John Wiley & Sons, Ltd.
CICADA: a novel scheme for improving TCP performance over wireless links
Authors: Ghaboosi Kaveh , Khalaj Babak Hossein
Published: June 2005

In this paper, by making slight modifications in protocol stack of wireless access points, the proposed CICADA scheme aims at isolating problems related to wireless section of a transmission control protocol (TCP) connection from its wired portion, using IP spoofing and virtual protocol stack scheme. As the simulation results for an 802.11 based system show, the proposed scheme improves the overall network throughput for both DCF and PCF scenarios, while reducing the mean and variance of end‐to‐end delay for voice and video flows due to smarter bandwidth allocation to elastic and real‐time traffic. In addition, the proposed scheme uses a centralized network address translation (NAT) structure that prevents undesired disconnections during handovers and achieves a smaller handoff delay compared with other schemes. CICADA also improves the privacy of wireless sections by constructing virtual protocol stacks corresponding to mobile stations and using hierarchical two‐level NAT structure in infrastructure networks in order to protect the distribution system against outside attacks. Copyright © 2005 John Wiley & Sons, Ltd.
Linking lacustrine cycles with syn-sedimentary tectonic episodes: an example from the Codó Formation (late Aptian), northeastern Brazil
Authors: PAZ J. D. S. , ROSSETTI D. F.
Published: June 2005

The Codó Formation exposed in the eastern Grajaú Basin, northeastern Brazil, consists mostly of black shales, limestones and evaporites arranged into several shallowing-upward cycles formed by progradation of lake deposits. Three ranks of cycles are distinguished. The lower-rank cycles correspond to millimetric interbeddings of: bituminous black shales with evaporites, calcimudstones or peloidal wackestone–packstone; grey/green shale with calcimudstone, peloidal wackestone–packstone or ostracodal wackestone/grainstone; and ostracodal wackestone/grainstone and/or calcimudstones with cryptomicrobial mats and ooidal/pisoidal packstones. The intermediate-rank cycles average 1.7 m in thickness and are formed by complete and incomplete cycles. Complete cycles show a transition from central to intermediate and then to marginal facies associations and include two types: C1 cycle with central lake deposits consisting of evaporites and black shales; and C2 cycle with central lake deposits formed by grey/green shale. Complete cycles were produced by the upward gradation from central to marginal environments of the lake or saline pan–sabkha system. Incomplete cycles are those where at least one facies association is lacking, having been formed by successions either with central and intermediate facies associations (I1) or intermediate and marginal facies associations (I2). The higher-rank cycles are, on average, 5.2 m thick and consist of four depositional units that display shallowing-upward successions formed by complete and incomplete intermediate-rank cycles that vary their distribution upward in the section, and are bounded by sharp surfaces. While the lower-rank cycles display characteristics that reveal their seasonal signature, detailed sedimentological characterization and understanding of stratal stacking patterns related to the intermediate and higher-rank cycles support a genesis linked to syn-sedimentary tectonic activity. This is particularly suggested by the high facies variability, limited lateral extension, and frequent and random thickness changes of the intermediate-rank cycles. Additionally, the four higher-rank cycles recognized in the Codó Formation match with stratigraphic zones having different styles of soft-sediment deformation structures attributed to seismic activities. Therefore, the several episodes of lake shallowing recorded in the Codó Formation are linked to seismic pulses that alternated with sediment deposition. This process would have created significant changes in the lake water level and resulted in sharply bounded successions with upward gradation from deeper to relatively shallower facies associations.
Peace parks in Southern Africa: bringers of an African Renaissance?
Authors: van Amerom Marloes , Büscher Bram
Published: June 2005

The pursuit of an African Renaissance has become an important aspect of regional cooperation between South Africa and its neighbours. Transfrontier conservation areas, or ‘Peace Parks’ as they are popularly called, have been identified as key instruments to promote the African Renaissance dream, and are increasingly advocated and justified on this basis. By fostering joint conservation (and tourism) development in Southern Africa's marginalised border regions, Peace Parks are claimed to further international peace, regional cooperation and poverty reduction, and thus serve basic ideals of the African Renaissance. This article critically explores this assumption. Using the joint South African-Mozambican-Zimbabwean Great Limpopo Park as a case study, it argues that in reality the creation of Peace Parks hardly stimulates and possibly even undermines the realisation of the African Renaissance ideals of regional cooperation, emancipation, cultural reaffirmation, sustainable economic development and democratisation. So far, their achievement has been severely hindered by domination of national interests, insufficient community consultation, and sensitive border issues such as the illegal flows of goods and migrants between South Africa and neighbouring countries. Furthermore, exacerbation of inter-state differences induced by power imbalances in the region, and harmonisation of land use and legal systems across boundaries, are increasingly becoming sources of conflict and controversy. Some of these problems are so severe, we conclude, that they might eventually even undermine support for African Renaissance as a whole. Utmost care is thus required to optimally use the chances that Peace Parks do offer in furthering an African Renaissance.
Business, government and economic policymaking in the new South Africa, 1990–2000
Authors: Handley Antoinette
Published: June 2005

The stated economic policy of the African National Congress (ANC) underwent a dramatic shift in the 1990s, away from a soft-left redistributionist position to one much more closely aligned with the policy preferences of the South African business community. To what extent can this shift be attributed to lobbying efforts by that community? The article reviews the development of economic policy by the ANC in the 1990s, and concludes that while business was undoubtedly influential in this process, much of that influence was indirect and derived from two sets of sources: first, the international policy consensus around the neo-liberal reform agenda; and second, indirect signals from ‘the market’ by means of such mechanisms as movements in the value of the currency, and investor and business confidence.
Engendering civil society: oil, women groups and resource conflicts in the Niger Delta region of Nigeria
Authors: Ikelegbe Augustine
Published: June 2005

Civil society has been an active mobilisational and agitational force in the resource conflicts of the Niger Delta region in Nigeria. The paper examines the gender segment of civil society and its character, forms and roles in these conflicts. The central argument is that marginality can be a basis of gendered movements and their engagement in struggles for justice, accommodation and fair access to benefits. Utilising secondary data and primary data elicited from oral interviews, the study identifies and categorises women groupings and identifies their roles and engagements in the oil economy. It finds that community women organisations (CWOs), with the support of numerous grass-roots women organisations, are the most active and frequently engaged in the local oil economies, where they have constructed and appropriated traditional women protests as an instrument of engagement. The paper notes the implications of women protest engagements and particularly their exasperation with previous engagements, the depth of their commitments, and the extension of the struggle beyond the threshold of normal social behaviour.