bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanism of inhibitory effect of citalopram on isolated guinea‐pig atria in relation to adenosine receptor
Authors: Pousti Abbas , Deemyad Tara , Malihi Golrokh
Published: May 2004

The effect of citalopram (CTP), a selective serotonin reuptake inhibitor antidepressant was studied on the rate and force of contractions of isolated guinea‐pig atria. CTP (2–32 μg/ml) caused a dose‐dependent decrease in the contractile force (7%–62%) and in the rate of contractions (11%–72%). These negative inotropic and chronotropic effects of CTP (8 μg/ml) were not prevented by atropine (1 μg/ml) and 3,7 dimethyl‐1‐propargylxanthine (DMPX; 1.5 μg/ml), an adenosine A2 receptor antagonist, but 1,3 dipropargyl‐8‐cyclopentylxanthine (DPCPX; 12 μg/ml), a specific adenosine A1 receptor antagonist significantly blocked these effects (p < 0.001) and theophylline (30 μg/ml) a non‐selective adenosine A1/A2A receptor antagonist also prevented the inotropic and chronotropic effects of CTP. These results suggest that the negative inotropic and chronotropic effect of CTP on isolated guinea‐pig atria is probably mediated through an inhibition of the uptake of adenosine or the A1 receptor mechanism. Copyright © 2004 John Wiley & Sons, Ltd.
Clomipramine, fluoxetine and CYP2D6 metabolic capacity in depressed patients
Authors: Vandel P. , Haffen E. , Nezelof S. , Broly F. , Kantelip J. P. , Sechter D.
Published: May 2004

Cytochrome P450‐2D6 may be involved in the metabolism of many drugs such as psychotropic drugs and its genetic polymorphism is responsible for inter‐individual differences in the therapeutic effect and toxicity of these drugs. Moreover with the same genetic basis, CYP2D6 metabolic capacity variations are observed. Different factors of variation may be involved, among them the prescribed drugs.

The aim of this study was to compare the influence of two types of antidepressants, tricyclic (clomipramine) and serotonergic specific recapture inhibitor (SSRI) (fluoxetine), on the CYP2D6 metabolic capacity of depressed inpatients. The CYP2D6 phenotype (dextromethorphan test) was determined in 56 genotyped (PCR‐SSCP) depressed caucasian inpatients with a heterozygous genotype. Forty‐five subjects were treated with clomipramine and eleven received fluoxetine. The dextromethorphan metabolic ratio (MR) median was significantly higher in the fluoxetine group (0.255) than in the clomipramine group (0.083, p < 0.014). In this study, fluoxetine involved a greater decrease of CYP2D6 metabolic capacity than clomipramine. Clinical implications and the possible connection between a decreased CYP2D6 activity and adverse drug effects were discussed. Caution should be taken when drugs with a low therapeutic index must be coprescribed in such patients. Copyright © 2004 John Wiley & Sons, Ltd.
The impact of ecological risk and perceived discrimination on the psychological adjustment of African American and European American youth
Authors: Prelow Hazel M. , Danoff‐Burg Sharon , Swenson Rebecca R. , Pulgiano Dana
Published: May 2004

The purpose of the present study was to examine the role of cumulative ecological risk (i.e., neighborhood disadvantage and ecologically salient stressful events) and perceived discrimination on the psychological adjustment of urban African American and European American youth. Findings indicated that both cumulative ecological risk and perceived discrimination were associated with poorer psychological adjustment for youth in this study. Hierarchical regression analyses revealed that cumulative ecological risk made a unique contribution to each of the outcome variables. Moreover, perceived discrimination amplified the effect of ecological risk when delinquency was the criterion for African American youth but not for their European American peers. However, contrary to our expectations, perceived discrimination did not moderate the effect of ecological risk when depressive symptomatology was the outcome variable. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 375–389, 2004.
Social support in women with fibromyalgia: Is quality more important than quantity?
Authors: Franks Heather M. , Cronan Terry A. , Oliver Karen
Published: May 2004

The present study is an examination of the effects of quality and quantity of social support on the psychological and physical well‐being of women with fibromyalgia syndrome (FMS). Participants were 568 women who were members of a health maintenance organization (HMO) with a confirmed diagnosis of FMS. Participants were administered a battery of questionnaires assessing their psychological and physical well‐being. Measures of depression, self‐efficacy, helplessness, mood disturbance, health status, impact of FMS, and social support were included. Regression analyses indicated that larger social support networks were associated with greater levels of self‐efficacy for pain and symptom management, while the perceived quality of social support was associated with lower levels of depression, helplessness, mood disturbance, impact of FMS, higher levels of self‐efficacy for function and symptom management, as well as overall psychological well‐being. These findings indicate that the quality of social support is more important than quantity in determining outcomes in women with FMS. Thus, the quality of social support has important financial and psychosocial implications for the individual and for the community as a whole. Future research should examine longitudinal changes in quality of social support and the corresponding changes in health status and psychological well‐being, as well as the effects of integrating manipulations designed to affect the quality of social support into community interventions designed to enhance the well‐being of women with FMS. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 425–438, 2004.
Who do young adult victims of physical assault talk to about their experiences?
Authors: Thomson Rob , Langley John
Published: May 2004

Many victims of physical assaults do not report the assault to the police. In this study we examine whom these victims talked to and how satisfied they were with the help they received. A sample of 374 participants of the Dunedin Multidisciplinary Health and Development Study (DMHDS) who had been assaulted in the preceding 12 months, were asked questions about an assault that had the greatest impact on their life and who they had talked to about it. It was found that not only did very few participants report the assault to the police; most victims talked to no one. If they did talk to someone, they were more likely to talk to friends and family and find them more helpful than the police and other services. Talking to others appears to be influenced by the nature of the assault, as participants were most likely to report serious assaults resulting in injuries requiring medical attention. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 479–488, 2004.
Targeting of HLA‐DR molecules transduces agonistic functional signals in cutaneous melanoma
Authors: Altomonte Maresa , Visintin Alberto , Tecce Raffaele , Leonardi Antonio , Calabro Luana , Fonsatti Ester , Pucillo Carlo , Maio Michele
Published: May 2004

The role of human leukocyte antigens (HLA) class II molecules in transducing intracellular signals in immune cells is well established. Solid tumors of different histotype can also express HLA class II antigens; however, their intracellular signaling ability is essentially unknown. Due to the frequent expression of HLA class II molecules in primary and metastatic lesions, cutaneous melanoma was utilized to investigate whether the engagement of HLA‐DR molecules transduces functional intracellular signal(s). Triggering of HLA‐DR molecules by the anti‐HLA‐DR monoclonal antibody (mAb) L243 induced a significant (P < 0.05) and dose‐dependent growth‐inhibition of metastatic melanoma cells Mel 120, as well as their homotypic aggregation. Furthermore, an increase in tyrosine phosphorylation of multiple cellular proteins with a molecular weight ranging from 66 to 130 kD, including p125 focal adhesion kinase, was observed. Lastly, the engagement of HLA‐DR molecules by mAb L243 inhibited activator protein‐1‐DNA binding. Thus, HLA‐DR molecules expressed on melanoma cells can transduce functional intracellular signals. This finding is consistent with evidences obtained in hematological malignancies, and suggests the potential usefulness of HLA‐DR molecules to set‐up new approaches of targeted therapy in metastatic melanoma. © 2004 Wiley‐Liss, Inc.
Decreased expression of peroxisome proliferator activated receptor γ in CFTR−/− mice
Authors: Ollero Mario , Junaidi Omer , Zaman Munir M. , Tzameli Iphigenia , Ferrando Adolfo A. , Andersson Charlotte , Blanco Paola G. , Bialecki Eldad , Freedman Steven D.
Published: May 2004

Some of the pathological manifestations of cystic fibrosis are in accordance with an impaired expression and/or activity of PPARγ. We hypothesized that PPARγ expression is altered in tissues lacking the normal cystic fibrosis transmembrane regulator protein (CFTR). PPARγ mRNA levels were measured in colonic mucosa, ileal mucosa, adipose tissue, lung, and liver from wild‐type and cftr−/− mice by quantitative RT‐PCR. PPARγ expression was decreased twofold in CFTR‐regulated tissues (colon, ileum, and lung) from cftr−/− mice compared to wild‐type littermates. In contrast, no differences were found in fat and liver. Immunohistochemical analysis of PPARγ in ileum and colon revealed a predominantly nuclear localization in wild‐type mucosal epithelial cells while tissues from cftr−/− mice showed a more diffuse, lower intensity labeling. A significant decrease in PPARγ expression was confirmed in nuclear extracts of colon mucosa by Western blot analysis. In addition, binding of the PPARγ/RXR heterodimer to an oligonucletotide containing a peroxisome proliferator responsive element (PPRE) was also decreased in colonic mucosa extracts from cftr−/− mice. Treatment of cftr−/− mice with the PPARγ ligand rosiglitazone restored both the nuclear localization and binding to DNA, but did not increase RNA levels. We conclude that PPARγ expression in cftr−/− mice is downregulated at the RNA and protein levels and its function diminished. These changes may be related to the loss of function of CFTR and may be relevant to the pathogenesis of metabolic abnormalities associated with cystic fibrosis in humans. © 2004 Wiley‐Liss, Inc.
Cycles and paths in graphs with large minimal degree
Authors: Nikiforov V. , Schelp R. H.
Published: May 2004

Let G be a simple graph of order n and minimal degree > cn (0 < c < 1/2). We prove that (1) There exist n0 = n0(c) and k = k(c) such that if n > n0 and G contains a cycle Ct for some t > 2k, then G contains a cycle Ct − 2s for some positive s < k; (2) Let G be 2‐connected and nonbipartite. For each ε(0 < ε < 1), there exists n0 = n0(c,ε) such that if n ≥ n0 then G contains a cycle Ct for all t with $\left \lceil { 2\over c}\right \rceil -2\leq t\leq 2(1-\varepsilon) cn$. This answers positively a question of Erdős, Faudree, Gyárfás and Schelp. © 2004 Wiley Periodicals, Inc. J Graph Theory 47: 39–52, 2004
Demonstration of multiple novel glycoforms of the stem cell survival factor CCg
Authors: Dahl A. , Eriksson P.S. , Davidsson P. , Persson A.I. , Ekman R. , Westman‐Brinkmalm A.
Published: May 2004

We have investigated the presence of different glycoforms of cystatin C secreted by adult hippocampal rat‐derived stem/progenitor cells (AHPs) into conditioned medium. A glycosylated form of cystatin C (CCg) has been identified previously in conditioned medium from AHPs as an autocrine/paracrine cofactor. Fibroblast growth factor‐2 (FGF2) requires cooperation with CCg to support AHP survival at low density in vitro. The purpose of the present study was to investigate further if cystatin C consists of one glycoform or if several different glycoforms are secreted by AHPs in vitro. The presence of the glycoforms was studied using enzymatic deglycosylation in conjunction with gel electrophoresis and Western blotting. The glycoforms of cystatin C were isolated with a combination of gel electrophoresis and electroelution, yielding the intact glycoforms in liquid phase before enzymatic deglycosylation. Our results revealed several novel glycoforms, in contrast to previous publication. The results suggest that N‐ and O‐linked glycans with sialic acid are attached to cystatin C. Furthermore, we have demonstrated that all glycoforms are present in conditioned medium after only 48 hr of culturing and that all nestin‐positive AHPs are immunopositive against cystatin C. These findings suggest secretion of the glycoforms by cultured AHPs. © 2004 Wiley‐Liss, Inc.
FK506 and a nonimmunosuppressant derivative reduce axonal and myelin damage in experimental autoimmune encephalomyelitis: Neuroimmunophilin ligand‐mediated neuroprotection in a model of multiple sclerosis
Authors: Gold Bruce G. , Voda Jan , Yu Xiaolin , McKeon Gabriel , Bourdette Dennis N.
Published: May 2004

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) in which demyelination and axonal loss result in permanent neurologic disability. We examined the neuroprotective property of the immunosuppressant FK506 (tacrolimus), FK1706 (a nonimmunosuppressant FK506 derivative) and cyclosporin A (CsA) in a chronic relapsing experimental autoimmune encephalomyelitis (EAE) model of MS. Female SJL/J mice were immunized by subcutaneous (s.c.) injection with proteolipid protein 139–151 peptide in complete Freund's adjuvant. At the onset of paralysis, 12–14 days after immunization, mice received daily s.c. injections of FK506 (0.2, 1, and 5 mg/kg), FK1706 (5 mg/kg), CsA (2, 10, and 50 mg/kg), saline or vehicle (30% dimethylsulfoxide) for 30 days. FK506 (at a dose of 5 mg/kg) reduced the severity of the initial disease and suppressed relapses. FK1706 did not significantly alter the clinical course and CsA (at a dose of 50 mg/kg) lessened the severity of the initial episode of EAE but did not alter relapses. In the thoracic spinal cord, FK506 (5 mg/kg), FK1706 (5 mg/kg), and CsA (50 mg/kg) significantly (P < 0.001) reduced the extent of damage in the dorsal, lateral, and ventral white matter by a mean of up to 95, 68, and 30%, respectively. A nonimmunosuppressant dose of FK506 (0.2 mg/kg) also significantly (P < 0.001) reduced the extent of damage in the spinal cord by a mean of up to 45%. Other dosages of these compounds were ineffective. FK506 markedly protects against demyelination and axonal loss in this MS model through immunosuppression and neuroprotection. © 2004 Wiley‐Liss, Inc.
Enhanced production and proteolytic degradation of insulin‐like growth factor binding protein‐2 in proliferating rat astrocytes
Authors: Chesik Daniel , Kühl Nicole M. , Wilczak Nadine , De Keyser Jacques
Published: May 2004

Insulin‐like growth factors (IGFs) protect neurons, are important for oligodendrocyte survival and myelin production, and stimulate the proliferation of astrocytes. The effects of IGFs are regulated by a family of IGF binding proteins (IGFBPs). Astrocytes express predominantly IGFBP‐2. In the present study, primary neonatal rat astrocytes were cultivated in a chemically defined medium to initiate a differentiated cell status. After stimulation with fetal calf serum, astrocytes became hypertrophic and increased proliferation. Western blot analysis of cell lysate of proliferating astrocytes displayed an increased expression of IGFBP‐2. This finding was supported by immunocytochemical images. Semiquantitative polymerase chain reaction analysis demonstrated equal mRNA levels in both differentiated and proliferating astrocytes, suggesting that the increase in IGFBP‐2 production in proliferating astrocytes was exerted at the translational level. Concentrated medium of proliferating cells, however, displayed lower levels of IGFBP‐2 than differentiated cells. When recombinant IGFBP‐2 was incubated with culture media, we found degradation in the medium of proliferating cells, but not in medium of differentiated cells. This degradation could be inhibited with protease inhibitors, indicating that lower levels of IGFBP‐2 in the medium of proliferating astrocytes are due to the presence of proteases. Our results suggest that, in proliferating astrocytes, IGFBP‐2 may help target IGFs to IGF‐1 receptors, and IGFBP‐2 proteases may play a role in enhancing the availability of IGFs. © 2004 Wiley‐Liss, Inc.
Cerebrospinal fluid immunoglobulin G promotes oligodendrocyte progenitor cell migration
Authors: Tiwari‐Woodruff S.K. , Myers L.W. , Bronstein J.M.
Published: May 2004

Multiple sclerosis (MS) is characterized by demyelination of the CNS with associated neurological deficits. Remyelination can occur but is often incomplete. The process of myelin repair requires the proliferation and migration of oligodendrocyte progenitor cells (OPC) into the lesion from the neighboring areas. OPC migration is altered by several factors, including antibodies that bind to OPC surface proteins. We have previously reported elevated anti‐OSP/claudin‐11 antibodies in the cerebrospinal fluid (CSF) of MS patients and that anti‐OSP/claudin‐11 antibodies generated in rabbits can inhibit OPC migration. In the study presented here, we investigated the effect of CSF IgG from MS patients and controls on OPC migration in culture. Rat OPC cultured with CSF from MS patients tended to migrate more than those cultured with control CSF, but this did not reach statistical significance. To determine whether the IgG fraction in the CSF influenced migration, we removed it using protein‐A sepharose. A dramatic decrease in OPC migration was found in both MS (45 ± 24 vs.16 ± 9) and control (40 ± 19 vs. 22 ± 13) samples after IgG was removed (P < .05). Anti‐OSP/claudin‐11 antibody concentration did not significantly correlate with OPC migration. These data demonstrate that CSF IgG promotes OPC migration. Identification of the specific IgG fraction responsible for this effect could lead to novel therapies to promote recovery in MS. © 2004 Wiley‐Liss, Inc.
Cover Picture: Macromol. Chem. Phys. 8/2004
Authors: Renker Sabine , Mahajan Surbhi , Babski Diane T. , Schnell Ingo , Jain Anurag , Gutmann Jochen , Zhang Yuangming , Gruner Sol M. , Spiess Hans W. , Wiesner Ulrich
Published: May 2004

Cover: The cover shows the nanostructure and shape control in polymer‐inorganic hybrids and mesoporous materials as derived from poly(ethylene oxide)‐block‐poly(hexyl methacrylate) block copolymers as structure directing agents. In the polymer‐inorganic composites the PEO block is compatibilized with the inorganic aluminosilicate phase (center). With studies of such advanced materials the areas of polymer science and solid state materials are merged.

Further details can be found in the Full Paper by S. Renker, S. Mahajan, D. T. Babski, I. Schnell, A. Jain, J. Gutmann, Y. Zhang, S. M. Gruner, H. W. Spiess, and U. Wiesner* on page 1021.
Mathematical Modelling and Computer Simulation of Linear Polymer Degradation: Simple Scissions
Authors: Bose Sonia M. , Git Yoav
Published: May 2004

Summary: Degradation of a polymer in a reactor by the degrading agent(s) follows a distinct pattern, primarily influenced by structural integrity and reactor environment. This distinct pattern is recorded in the changes in the evolved molecular weight distribution (MWD) or polymer chain length distribution (PCLD) curve characteristics from the initial intact state. Modern size exclusion chromatography (SEC) is the best laboratory‐based method that can clearly provide these plots in the form of chromatogram; however, detailed molecular information is not available. The nature of molecular destruction can be well‐characterised if the distinct MWD shift patterns can be simulated to fingerprint the different chain scission dynamics. This is investigated by our current research using the power of computer simulation techniques to gain insight into the polymer ageing processes. One such technique for studying simple decay processes is presented here, and the results are compared with experimental findings. The concept of a binary tree scission model is introduced to show chain rupture as a sequence of probabilistic events and as a non‐linear function of time. Two new mathematical algorithms, an iterative Monte Carlo structured probability scheme and a semi‐iterative algebraic exact statistical formulation method, are investigated to implement this model and simulate the evolution of resultant temporal MW distribution. The latter, an innovative approach to mathematical modelling, has the potential to generate a statistically perfect instant MWD decay curve. A statistical comparison of the product yield is presented from the data obtained using a wide variety of simulated scission regimes to determine the sources of variability.

Simulated MWD lateral shift for percent cut scission model showing deviation from the initial MWD (red) over degradation time zones Tj(0 ≥ j ≤ 9) with bimodal and curve broadening effect due to accumulation of varied percent cut range 5–30%.

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Simulated MWD lateral shift for percent cut scission model showing deviation from the initial MWD (red) over degradation time zones Tj(0 ≥ j ≤ 9) with bimodal and curve broadening effect due to accumulation of varied percent cut range 5–30%.
Urotensin‐II receptor peptide agonists
Authors: Carotenuto Alfonso , Grieco Paolo , Novellino Ettore , Rovero Paolo
Published: May 2004

Urotensin II (U‐II) has been known for over 30 years as an important teleost fish hormone, but only recently has it been recognized as the endogenous ligand of a new human G‐protein‐coupled receptor (GPCR) homologous to the GPR14 orphan receptor from rat. Human U‐II was found to be a potent vasoconstrictor, widely distributed in human tissues, possibly contributing to several human cardiovascular diseases. It thus has become a major target of medicinal chemistry research. The common structural feature of U‐II peptides from different species is the C‐terminal portion, characterized by the disulfide bridged cyclic hexapeptide Cys‐Phe‐Trp‐Lys‐Tyr‐Cys. The few structure–activity relationship studies reported to date attributed a critical role to this portion, with the Trp‐Lys‐Tyr motif appearing as the key determinant of U‐II bioactivity. Consequently, this shorter cyclic peptide was used as a template for the development of several synthetic analogues, among which a superagonist, termed P5U: H‐Asp‐cyclo(Pen‐Phe‐Trp‐Lys‐Tyr‐Cys)‐Val‐OH. Conformational studies confirmed the important role of hU‐II C‐terminal cyclic portion, enabling the development of 3D pharmacophore models. These findings should lead to the design of new, potent and selective analogues, acting as agonist or antagonist at the human U‐II receptor, finally contributing to a deeper comprehension of the (patho)physiological significance of this peptide. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 5, 577–588, 2004
A conservative integral for bimaterial notches subjected to thermal stresses
Authors: Banks‐Sills Leslie , Ishbir Chaim
Published: May 2004

In this investigation, a conservative integral based on the Betti reciprocal principle is developed to obtain stress intensity factors for a bimaterial notch in which the body is subjected to a thermal load. The bonded materials are linear elastic, isotropic and homogeneous. According to the linear theory of elasticity, stresses in the neighbourhood of the notch tip are generally singular as a result of the mismatch of the elastic constants. Eigenvalues and eigenfunctions depend upon the mechanical properties and wedge angles. They may be real, complex or power‐logarithmic. Real and complex eigenvalues are considered in this study. The stress intensity factor represents the amplitude of the stress singularity and depends upon material properties, geometry and load or temperature. Because of the highly singular behaviour of one of the integrals that is part of the conservative integral, the former is carried out by a hybrid analytical/numerical scheme.

The finite element method is employed to obtain displacements caused by the temperature distribution in the body. The conservative integral is applied to several problems appearing in the literature. Both good agreement between those results and the ones obtained here, as well as path stability for all problems is attained. A wide range of material parameters is also studied. Copyright © 2004 John Wiley & Sons, Ltd.
A stabilized volume‐averaging finite element method for flow in porous media and binary alloy solidification processes
Authors: Zabaras Nicholas , Samanta Deep
Published: May 2004

A stabilized equal‐order velocity–pressure finite element algorithm is presented for the analysis of flow in porous media and in the solidification of binary alloys. The adopted governing macroscopic conservation equations of momentum, energy and species transport are derived from their microscopic counterparts using the volume‐averaging method. The analysis is performed in a single domain with a fixed numerical grid. The fluid flow scheme developed includes SUPG (streamline‐upwind/Petrov–Galerkin), PSPG (pressure stabilizing/Petrov–Galerkin) and DSPG (Darcy stabilizing/Petrov–Galerkin) stabilization terms in a variable porosity medium. For the energy and species equations a classical SUPG‐based finite element method is employed. The developed algorithms were tested extensively with bilinear elements and were shown to perform stably and with nearly quadratic convergence in high Rayleigh number flows in varying porosity media. Examples are shown in natural and double diffusive convection in porous media and in the directional solidification of a binary‐alloy. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization of the polymer of a dipyrrolyl monomer by pyrolysis mass spectrometry
Authors: Ertas Merve , Hacaloglu Jale , Toppare Levent
Published: May 2004

In this work, characterization of a homopolymer of succinic acid bis(4‐pyrrol‐1‐ylphenyl) ester prepared by galvonastatic polymerization was carried out by direct pyrolysis mass spectrometry. Although decomposition of the monomer yielding mainly butadionic acid and pyrrole occurred under the galvonastatic polymerization conditions, growth of the polymer through the pyrrole moieties was also achieved, yielding a ladder‐type polymer film. The polypyrrole chains contained both quinoid and aromatic units as in the case of polypyrrole, yet the extent of network structure was significantly diminished. A three‐step mechanism is proposed for the thermal decomposition process. The first step involves the cleavage of C4H4NC6H4O end groups. In the second step, decomposition of phenyl ester units and polypyrrole chains having quinoid structure takes place. The final stage of thermal degradation was attributed to decomposition of polypyrrole chains having aromatic structure. Copyright © 2004 Society of Chemical Industry
Robust linear anti‐windup synthesis for recovery of unconstrained performance
Authors: Grimm Gene , Teel Andrew R. , Zaccarian Luca
Published: May 2004

Fixed order anti‐windup augmentation is addressed by considering the dynamics of the mismatch between the constrained and unconstrained responses. The method utilizes LMIs, and the result parallels other recent LMI‐based anti‐windup synthesis methods. Robustness is directly addressed—which is not done in previous LMI work on anti‐windup. An optimal LMI‐based synthesis procedure is provided for static and plant‐order linear anti‐windup augmentation and the performance of the resulting design strategy is shown via a simulation example. Copyright © 2004 John Wiley & Sons, Ltd.
Control of manipulators in a constrained workspace by means of linked invariant sets
Authors: Blanchini Franco , Pellegrino Felice Andrea , Visentini Luca
Published: May 2004

We propose a new technique for controlling manipulators in constrained environments. Based on recent developments on constrained control theory, our approach basically consists in covering the admissible region of the configuration space by partially overlapping convex polyhedra arbitrarily fixed and forming a connected family. Each of these polyhedra, defined in the configuration space, is suitably extended in the state‐space (i.e. configuration‐plus‐velocity space) in order to maintain all the original connections among regions and to be a tracking domain of attraction for the system, i.e. a set of initial states from which a reference signal can be asymptotically approached without constraints violation during the transient. The connection path is not generated a priori, but it is automatically produced on‐line by a hierarchical feedback controller. A high‐level controller selects the confining polyhedron, to which the current state has to be transferred, which is the closest to the one containing the target reference. A low‐level controller solves the problem of locally tracking a suitable crossing point to the desired new region under constraints. The robustness of the scheme as well as the control effort constraints are also taken into account. Copyright © 2004 John Wiley & Sons, Ltd.
An SVD based strategy for receding horizon control of input constrained linear systems
Authors: Rojas Osvaldo J. , Goodwin Graham C. , Serón María M. , Feuer Arie
Published: May 2004

A sub‐optimal receding horizon control strategy for input constrained linear systems is presented. The strategy is based on a singular value decomposition (SVD) of the Hessian of the quadratic performance index generally considered in model predictive control (MPC). The singular vectors are employed to generate a basis function expansion of the unconstrained solution to the finite horizon optimal control problem. At each sampling time, a feasible control sequence is determined by selecting a variable subset of the basis representation. No solution to the associated quadratic program is needed. For cases in which the Hessian is poorly conditioned, the proposed strategy can provide a sub‐optimal solution with minimal performance degradation. Properties of the singular values of the Hessian are also studied: it is shown that, for sufficiently long prediction horizons, the singular values are arbitrarily close to the magnitude of the energy density spectrum of the system seen by the performance index. Copyright © 2004 John Wiley & Sons, Ltd.
Extended anti‐windup control schemes for LTI and LFT systems with actuator saturations
Authors: Wu Fen , Soto Marco
Published: May 2004

In this paper, the popular anti‐windup control scheme will be extended in two important directions. The first scenario is the control of LTI systems subject to actuators with both magnitude and rate constraints. The second case of extension is LFT systems with input saturations. Based on the extended Circle criterion, we will develop convex anti‐windup control synthesis conditions in the form of LMIs for each class of systems. The explicit anti‐windup controller formula are also provided to facilitate compensator construction. The effectiveness of proposed anti‐windup control schemes will be demonstrated using a flight control example. Copyright © 2004 John Wiley & Sons, Ltd.
Rheological Properties of Pastes Obtained from Starches Derived from Immature Cereal Kernels
Authors: Gambuś Halina , Gumul Dorota , Juszczak Lesław
Published: May 2004

The results presented in this work concern the starches of three basic varieties of cereal cultivated in Poland – wheat, rye and barley – harvested at different stages of maturity in 1997 and 1998. Starches from these kernels were isolated by a laboratory method. The flow curves and thixotropic properties of 5% starch pastes at 50°C and controlled shear rates between 0 and 600 s−1 were obtained. All the investigated starch pastes were non‐Newtonian, plastic and thixotropic fluids, that differed in their values of yield stress. The pastes from immature cereal starches were characterised by a higher plasticity because they needed a higher shear stress (τ) to achieve the yield stress (τ01) in comparison with the pastes from the mature cereal starches. At applied shear stress the pastes from the “immature” starches had a higher thixotropy in comparison with the “mature” ones. Pastes from immature starch were more susceptible towards shearing forces but at the same time they exhibited a better ability to rebuild their structure. The description of the flow curves by the Ostwald‐de Waele equation allows the conclusion that pastes from the immature starches have a higher structural viscosity. In addition, the application of the Casson model allows to describe the flow curves and determine the yield stress and the plasticity properties of the investigated pastes. However, the viscosity values calculated from the Casson model do not reflect differences in viscosity among the samples.
Age and tectonic evolution of Neoproterozoic ductile shear zones in the Southern Granulite Terrain of India, with implications for Gondwana studies
Authors: Ghosh Joy Gopal , de Wit Maarten J. , Zartman R. E.
Published: May 2004

The high‐grade rocks of the Southern Granulite Terrain (SGT) of Peninsular India are bounded to the north by the Archean Dharwar Craton. Another high‐grade terrane, the Mesoproterozoic Eastern Ghats, occurs to the northeast of the SGT. The tectonic relationship between these crustal domains is complex. We present new geochronological and structural data that indicate a continuation of the Dharwar Craton into the Southern Granulite Terrain as far south as a newly identified Neoproterozoic shear zone, here named the Karur‐Kamban‐Painavu‐Trichur Shear Zone (KKPTSZ). South of the KKPTSZ, Mesoproterozoic dates of the SGT are similar to those recorded in the Eastern Ghats, and the two domains may have been conterminous. Thirty‐three new U/Pb/Th single zircon and monazite dates of samples from six structural transects across the regional shear zones indicate that the SGT has experienced at least seven thermo‐tectonic events at 2.5 Ga, ∼2.0 Ga, ∼1.6 Ga, ∼1.0 Ga, ∼800 Ma, ∼600 Ma, and ∼550 Ma, and two distinct episodes of metasomatism/charnockitization between 2.50–2.53 and between 0.55–0.53 Ga. Deformation along a number of major shear zones in the SGT is Neoproterozoic to earliest Paleozoic in age, with an early phase (D2) concentrated between 700–800 Ma, and a later phase (D3) between 550 and 600 Ma. Major charnockitization (530–550 Ma) post dates D3, and is, in turn, overprinted by granitization, retrogression, and uplift between 525 and 480 Ma. The KKPTSZ, active between 560 and 570 Ma, is either a terrane boundary, or a tectonized décollement between cover and Archean basement rocks represented by predominantly paragneisses to the south and orthogneisses to the north, respectively. Other regional Neoproterozoic shear zones do not appear to separate allochthonous terranes as previously suggested on the basis of Nd model ages and Rb/Sr biotite/whole rock dates. The Neoproterozoic‐Cambrian tectonothermal history of the SGT and Eastern Ghats is similar to that recorded in parts of Madagascar, East Africa, and Antarctica, and is used to reconstruct parts of central Gondwana, here named the Deccan Continent, with more robust confidence.
Mechanisms of air‐sea CO2 flux variability in the equatorial Pacific and the North Atlantic
Authors: McKinley Galen A. , Follows Michael J. , Marshall John
Published: May 2004

A global ocean general circulation model is used to estimate the magnitude of interannual variability in air‐sea fluxes of CO2 and O2 from 1980–1998 and to examine the controlling mechanisms. The global variability in the air‐sea flux of carbon (±0.5 × 1015 grams Carbon yr−1 (PgC yr−1)) is forced by changes of ΔpCO2 and wind speeds related to the El Niño/Southern Oscillation (ENSO) cycle in the equatorial Pacific. In contrast the air‐sea O2 flux is controlled by two regions: the equatorial Pacific and North Atlantic. The model captures much of the interannual variability of the CO2 flux observed at Bermuda, with some correlation with the North Atlantic Oscillation (NAO) index. However, basin‐scale air‐sea CO2 flux anomalies are not correlated with the NAO due to a rapid neutralization of entrained DIC anomalies by biological uptake and export production in the subpolar gyre. CO2 flux variability estimates from our ocean model and the mean atmospheric inversion results of Bousquet et al. [2000] are in broad agreement in the equatorial Pacific, but not in the North Atlantic. This model suggests that the projection of air‐sea flux anomalies onto the large‐scale, mean air‐sea flux pattern in atmospheric inversions may lead to an overestimate of the flux variability in the extra‐tropics where the patterns of variability do not correspond to those of the mean flux.
Nonmigrating semidiurnal and diurnal tides at 95 km based on wind measurements from the High Resolution Doppler Imager on UARS
Authors: Huang Frank T. , Reber Carl A.
Published: May 2004

For more than a decade, derived results from the High Resolution Doppler Imager (HRDI) on UARS have provided an enormous amount of new and invaluable information on the global variability of atmospheric winds. These and other results have given added impetus to theoretical modeling efforts. Until recent years, the large majority of investigations have focused on migrating tides, and now more results on nonmigrating tides have become available. We provide new results for semidiurnal and diurnal nonmigrating tides based on data from HRDI at 95 km. Much of these results have not been obtained before, and they are substantially different from those that have been previously reported. Our amplitudes are usually significantly larger, with more periodicities in both day of year and latitude than results that have previously appeared in the literature. We also find components (up to longitude wave number 3) that are significant and have not been presented before and that traveling components of larger‐longitude wave numbers 4, 5, and 6 can reach several m/s in amplitude. We compare our results with earlier results based on HRDI measurements and from selected models.
A representer‐based inverse method for groundwater flow and transport applications
Authors: Valstar Johan R. , McLaughlin Dennis B. , te Stroet Chris B. M. , van Geer Frans C.
Published: May 2004

Groundwater inverse problems are concerned with the estimation of uncertain model parameters, such as hydraulic conductivity, from field or laboratory measurements. In practice, model and measurement errors compromise the ability of inverse procedures to provide accurate results. It is important to account for such errors in order to determine the proper weight to give to each source of information. Probabilistic descriptions of model and measurement errors can be incorporated into classical variational inverse procedures, but the computational demands are excessive if the model errors vary over time. An alternative approach based on representer expansions is able to efficiently accommodate time‐dependent errors for large problems. In the representer approach, unknown variables are expanded in finite series which depend on unknown functions called representers. Each representer quantifies the influence of a given measurement on the estimate of a particular variable. This procedure replaces the original inverse problem by an equivalent problem where the number of independent unknowns is proportional to the number of measurements. The representer approach is especially advantageous in groundwater problems, where the total number of measurements is often small. This approach is illustrated with a synthetic flow and transport example that includes time‐dependent model errors. The representer algorithm is able to provide good estimates of a spatially variable hydraulic conductivity field and good predictions of solute concentration. Its computational demands are reasonable, and it is relatively easy to implement. The example reveals that it is beneficial to account for model errors even when they are difficult to estimate.
Deriving high‐resolution sediment load data using a nonlinear deterministic approach
Authors: Sivakumar Bellie , Wallender Wesley W.
Published: May 2004

Accurate estimation of sediment load at high resolutions is crucial for river related activities. The existing methods for high‐resolution load estimation involve either extrapolation and interpolation schemes using high‐resolution water discharge and sediment concentration measurements or direct measurements using load movement detectors. The present study introduces a new (disaggregation) approach, which is based on scaling properties of the sediment load transformation process itself. The load transformation process between different scales is assumed as nonlinear deterministic. The disaggregation approach follows: (1) reconstruction of the scalar (sediment load) series in a multidimensional phase‐space for representing the transformation dynamics; and (2) use of a local approximation (nearest neighbor) method for disaggregation. The effectiveness of the approach is demonstrated by employing it to suspended sediment load data observed in the Mississippi River basin. Data of successively doubled resolutions between daily and 16 days (i.e., daily, 2‐day, 4‐day, 8‐day, and 16‐day) are studied, and disaggregations are attempted between successive resolutions (i.e., 2‐day to daily, 4‐day to 2‐day, 8‐day to 4‐day, and 16‐day to 8‐day). Comparison between the disaggregated values and the actual values (through statistical indicators, time series and scatterplots) reveal excellent agreements for all the cases studied, indicating the suitability of the nonlinear deterministic approach for sediment load disaggregation. The possible nonlinear deterministic nature of the sediment load transformation process between different scales is also evident from the best disaggregation results achieved for low phase‐space dimensions (less than 4) and small number of neighbors (less than 100).
Selective deposition of a gadolinium(III) cluster in a hole opening of single-wall carbon nanohorn
Authors: Hashimoto Ayako , Yorimitsu Hideki , Ajima Kumiko , Suenaga Kazutomo , Isobe Hiroyuki , Miyawaki Jin , Yudasaka Masako , Iijima Sumio , Nakamura Eiichi
Published: May 2004

Selective synthesis of particles of angstrom to nanometer size consisting of one to many metal atoms is instrumental in various applications, but it has been hampered by the tendency of the metal atom to form large clusters. We found, as studied by the state-of-the-art electron microscopic technique, a strategy to produce metal-containing nanoparticles isolated from each other by depositing metal atoms in a hydrophilic hole on or in the interior of a carbon nanotube as demonstrated by the reaction of Gd(OAc)
3
with oxidized single-wall nanohorns. Besides the potential utilities of the deposited metal clusters, the metal deposition protocol provides a method to control permeation of molecules through such openings.
Trade Unions in Local and Regional Development and Governance: The Northern Trades Union Congress in North East England
Authors: Pike Andy , O'Brien Peter , Tomaney John
Published: May 2004

From a position of relative isolation, trade unions have become increasingly important agents in local and regional development and governance in the UK since the election of the New Labour government in 1997. Analysis of the experience of the Northern Trades Union Congress (NTUC) suggests that devolution and regionalisation are exerting increasing pressures upon trade union federations to adopt a multi-level approach to organisation across a range of scales—local, sub-regional, regional, sub-national, national and international—to connect with the evolving multi-layered governance structures of the UK political economy. Strategic multi-level organisation suggests the decentralisation of power, authority and resources within the labour movement—challenging the national and centralised legacy of its collective bargaining history—and a division of labour and set of priorities at the different scales to build the links between local and regional engagement and trade union renewal.
‘Race’, Employment, and Contract Compliance: A Way Forward for Local Authorities?
Authors: Orton Michael , Ratcliffe Peter
Published: May 2004

The concern of this article is with action at the local level to combat racial inequality in employment. It draws on the authors' evaluation of the ‘West Midlands Common Standard’, an innovative policy introduced by a consortium of West Midlands councils to ensure their contractors have, and implement, an equal opportunities in employment policy. The article assesses the impact of the initiative and its potential transferability. It is argued that the Common Standard provides a highly promising model for other local authorities to adopt.
Phylogenetic analysis of wild-type 1 polioviruses isolated during the final period of transmission in Turkey
Authors: Özkaya Etem , Ishiko Hiroaki , Miura Rika , Shimada Yasushi , Alaeddinoglu Iffet , Artuk Cigdem , Miyamura Kikuko , Yamazaki Shudo
Published: May 2004

The last poliomyelitis case associated with a wild poliovirus in Turkey occurred in November 1998. This was the last known case of paralytic poliomyelitis caused by indigenous wild poliovirus in the World Health Organization's European Region. This study investigated the genetic relationships of wild-type 1 polioviruses at the latest period of transmission. A phylogenetic tree was constructed on the basis of the VP1/2A sequence from 14 wild-type 1 polioviruses isolated from Turkey in 1994–1998, along with those from other areas of the world. The Turkey isolates in the latest period of transmission were closely related to each other, forming a cluster distinct from other strains. The results showed that these viruses had been spreading indigenously in the eastern and south-eastern parts of Turkey, and ceased transmission there during 1998. This finding serves as a reference for future poliovirus surveillance both in Turkey and worldwide.
The cell cycle and how it is steered by Kaposi's sarcoma-associated herpesvirus cyclin
Authors: Verschuren Emmy W. , Jones Nic , Evan Gerard I.
Published: May 2004

A timely coordination of cellular DNA synthesis and division cycles is governed by the temporal and spatial activation of cyclin-dependent kinases (Cdks). The primary regulation of Cdk activation is through binding to partner cyclin proteins. Several gammaherpesviruses encode a viral homologue of cellular cyclin D, which may function to deregulate host cell cycle progression. One of these is encoded by Kaposi's sarcoma-associated herpesvirus (KSHV) and is called K cyclin or viral cyclin (v-cyclin). v-Cyclin is expressed in most of the malignant cells that are associated with KSHV infection in humans, labelling v-cyclin as a putative viral oncogene. Here are described some of the major structural and functional properties of mammalian cyclin/Cdk complexes, some of which are phenocopied by v-cyclin. In addition, the molecular events leading to orderly progression through the G1/S and G/M cell cycle phases are reviewed. This molecular picture serves as a platform on which to explain v-cyclin-specific functional properties. Interesting but largely speculative issues concern the interplay between v-cyclin-mediated cell cycle deregulation and molecular progression of KSHV-associated neoplasms.