bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of novel antigens recognized by serum autoantibodies from anti‐CD1 TCR‐transgenic lupus mice
Authors: Hueber Wolfgang , Zeng Defu , Sharpe Orr , Robinson William H. , Strober Samuel , Utz Paul J. 
Published: May 2004

AbstractIn this study, we further characterize the humoral autoimmune response in the recently described anti‐CD1 autoreactive T cell receptor‐transgenic mouse lupus model (CD1 lupus model). We discovered and characterized novel autoantigens, comprising a protein of 105 kDa (p105) and a novel RNA molecule of 140 base pairs (bp) that is likely associated with p105, and several additional factors with distinct biochemical properties. In the CD1 lupus model, lethally irradiated BALB/c/nu/nu mice were injected intravenously with sorted bone marrow cells and sorted splenic T cells from donor BALB/c mice expressing TCR α and β transgenes that encode autoreactivity for CD1d. Adoptive hosts injected with the single‐positive (CD4+ and CD8+) subset of transgenic cellsdeveloped anti‐double‐stranded DNA antibodies and a lupus‐like illness. Sera were analyzed by Western blotting and immunoprecipitation. Antigens were characterized by biochemical and serological methods. Serum autoantibodies from 5 of 12 (42%) CD1 lupus mice immunoprecipitated a 105‐kDa protein, termed p105. p105 was associated with a small RNA of ∼140 bp. Anti‐p105 autoantibodies appeared early in the course of disease. Serological and biochemical characterization suggested that p105 was distinct from known lupus autoantigens of similar molecular masses, indicating that p105 represents anovel autoantigen in lupus.
Extended presentation of specific MHC‐peptide complexes by mature dendritic cells compared to other types of antigen‐presenting cells
Authors: Zehn Dietmar , Cohen Cyril J. , Reiter Yoram , Walden Peter 
Published: May 2004

AbstractDendritic cells are known as the most potent antigen‐presenting cells for the induction of T cell‐mediated immune responses. To discriminate between the presentation of antigens and the co‐stimulatory aspects of this high immunostimulatory capacity, we used recombinant antibodies with T cell receptor‐like specificity to detect defined MHC‐peptide complexes on living cells. Mature human dendritic cells (mDC) were compared with immature DC (iDC), monocytes, CD4+ T lymphocytes, melanoma cells, T2 cells and B lymphoblastoid cells for their capacity to present MHC class I‐restricted tumor‐associated T cell epitopes and were found to display the specific peptides two to six times longer than other cells. The most short‐lived peptide had an average half‐life of 8.7 h on mDCvs. 3.5 h on B lymphoblastoid cells, while the most long‐lived peptide had a half‐life of 118.5 h vs. 20.7 h on these two cell types. The decay kinetics of specific MHC‐peptide complexes on iDC were among the fastest observed. The high potency of dendritic cells to induce specific T cell responses is thus based, in addition to the expression of co‐stimulatory molecules, on an extended antigenic memory, which increases the likelihood and the extent of contacts between dendritic cells and antigen‐specific T cells.
AgC10, a mucin from Trypanosoma cruzi, destabilizes TNF and cyclooxygenase‐2 mRNA by inhibiting mitogen‐activated protein kinase p38
Authors: Alcaide Pilar , Fresno Manuel 
Published: May 2004

AbstractSecretion of proinflammatory mediators by activated macrophages plays an important role in the immune response to Trypanosoma cruzi. We have previously reported that AgC10, a glycosylphosphatidylinositol‐anchored mucin from T. cruzi, inhibits TNF secretion by activated macrophages (de Diego, J., Punzon, C., Duarte, M. and Fresno, M., Alteration of macrophage function bya Trypanosoma cruzi membrane mucin. J. Immunol. 1997. 159: 4983–4989). In this report we have further investigated the molecular mechanisms underlying this inhibition. AgC10 inhibited TNF, IL‐10 and cyclooxygenase‐2 (COX‐2) synthesis by macrophages activated with LPS or LPS plus IFN‐γ in a dose‐dependent manner. AgC10 did not affect other aspects of macrophage activation induced by LPS, such as inducible nitric oxide synthase (iNOS) expression. AgC10 also had no effect on TNF or COX‐2 transcription or the induction of their promoters but inhibited the stability of TNF and COX‐2 mRNA, which are regulated post‐transcriptionally by the mitogen‐activated protein kinase (MAPK) p38 pathway. AgC10 was found to inhibit both the activation and the activity of p38 MAPK, since MAPK activated protein kinase‐2 (MAPKAP‐K2 or MK‐2) phosphorylation was also strongly inhibited. This led to TNF and COX‐2 mRNA destabilization. In contrast, AgC10 did not affect p38 activation induced by TNF. Furthermore, AgC10 inhibition must lie upstream in the MAPK activation pathway by LPS, since this mucin also inhibited extracellularly regulated kinase (ERK) and Jun kinase (JNK)activation.
Interferon γ suppresses glucocorticoid augmentation of macrophage clearance of apoptotic cells
Authors: Heasman Sarah J. , Giles Katherine M. , Rossi Adriano G. , Allen Judith E. , Haslett Christopher , Dransfield Ian 
Published: May 2004

AbstractOne of beneficial effects of glucocorticoids (GC) in inflammation may be the augmentation of macrophages' capacity for phagocytosis of apoptotic cells, a process that has a central role in resolution of inflammation. Here we define the phenotype of GC‐treated monocyte‐derived macrophages, comparing to IFN‐γ‐treated and IL‐4‐treated monocyte‐derived macrophages and combinatorial treatment. Our data indicate that the cytokine microenvironment at an inflammatory site will critically determine monocyte functional capacity following treatment with GC. In particular, whilst GC exert dominant regulatory effects over IFN‐γ in terms of cell surface receptor repertoire and morphology, the acquisition of a macrophage capacity for clearance of apoptotic cells is prevented bycombined treatment. In terms of mechanism, GC augmentation of phagocytosis was reversed even when monocytes were pre‐incubated with GC for the first 24 h of culture, a period that is critical for induction of a highly phagocytic macrophage phenotype. These findings have important implications for the effectiveness of GC in promoting acquisition of a pro‐phagocytic macrophage phenotype in inflammatory diseases associated with high levels of IFN‐γ
Homophilic interaction of NTBA, a member of the CD2 molecular family: induction of cytotoxicity and cytokine release in human NK cells
Authors: Falco Michela , Marcenaro Emanuela , Romeo Elisa , Bellora Francesca , Marras Daniele , Vély Frédéric , Ferracci Géraldine , Moretta Lorenzo , Moretta Alessandro , Bottino Cristina 
Published: May 2004

AbstractNK‐T‐B antigen (NTBA) is a CD2 family member that functions as a coreceptor in human NK cell activation. Several receptor/ligand interactions occur between different members of this molecular family. In this study, in order to identify the natural ligand of NTBA, we produced a chimeric protein formed by the NTBA extracellular region fused with the Fc portion of human IgG1 (termed NTBA‐Fc*). NTBA‐Fc* specifically binds to NTBA cell transfectants but not to cells transfected with other CD2 family members including CD2, CD48, CD84, CD150, CD229, and CD244. Moreover, NTBA‐Fc* also binds to NTBA+ but not to NTBA– T cell lines. Enzyme‐linked immunosorbent assays, plasmon resonance analysis, as well as NTBA‐Fc*‐mediated down‐regulation of NTBA surface expression further confirmed the occurrence of NTBA/NTBA homophilic interaction. Functionally, in NK cells, NTBA‐Fc* promoted a strong production of IFN‐γ and TNF‐α. Moreover, NTBA‐transfected targets displayed increased susceptibility to NK‐mediated killing as compared to untransfected cells and this effect was specifically inhibited by anti‐NTBA mAb. Altogether our data indicate that NTBA is characterized by self recognition.
The frictional resistance characteristics of a bedrock‐influenced river channel
Authors: Heritage G. L. , Moon B. P. , Broadhurst L. J. , James C. S. 
Published: May 2004

AbstractMuch of the published literature relating to reach‐scale total ﬂow resistance concentrates on alluvial rivers and little mention is made of the more extreme resistance found in bedrock‐inﬂuenced river systems. This paper presents the results of a detailed investigation of total ﬂow resistance variation for ﬁve channel types on the Sabie River, South Africa (cohesive mixed anastomosed, uncohesive mixed anastomosed, mixed pool–rapid, alluvial braided and alluvial single thread) over a range of discharges. Manning's ‘n’ and Darcy‐Weisbach f resistance coefﬁcients are calculated using Barnes' methodology (H. H. Barnes, US Geological Survey Water Supply Paper 1849, 1967). These data are analysed at the scales of channel type and morphologic unit and the resultant resistance values are compared with the literature. Generally the low‐ﬂow friction values estimated for the bedrock‐inﬂuenced channel types are higher than any reported. Flow resistance quantiﬁcation of the alluvial channel type study sites on the Sabie River produced values slightly higher than earlier studies of similar morphologies. In situations where signiﬁcant areas of irregular bedrock are exposed (cohesive mixed anastomosed and mixed pool–rapid channel types) the high ﬂow resistance coefﬁcients at low discharges probably reﬂect energy dissipation due to hydraulic jumps and internal distortions; however, these values fall as discharge increases to values comparable to those recorded for step–pool rivers. It is suggested that the slightly elevated resistance coefﬁcients recorded in the alluvial channel types are the result of the vegetation roughness component, operating when the macro‐channel bar features are inundated. Copyright © 2004 John Wiley & Sons, Ltd.
Centrosome amplification and aneuploidy in bone marrow failure patients
Authors: Kearns William G. , Yamaguchi Hiroki , Young Neal S. , Liu Johnson M. 
Published: May 2004

AbstractPatients with bone marrow failure are at risk for development of hematopoietic progenitor clones with abnormal numbers of chromosomes (aneuploidy) and leukemia. Numerical centrosome abnormalities or mutations in genes associated with the mitotic spindle checkpoint (BUB1 and MAD2) are two important mechanisms that can induce abnormal mitosis resulting in aneuploid daughter cells. To assess the role of these mechanisms, we used fluorescence in situ hybridization techniques to determine aneuploidy and centrosome copy number and PCR‐SSCP to identify gene mutations of BUB1 and MAD2 in marrow cells of 25 patients. No mutations were found in BUB1 or MAD2 genes. However, we found that cells with more than two centrosomes exhibited aneuploidy for three or more chromosomes. We conclude that centrosome amplification may be associated with the development of a clonal population of potentially preleukemic aneuploid cells. © 2004 Wiley‐Liss, Inc.
Rural tourism in Spain
Authors: Barke Michael 
Published: May 2004

AbstractThe paper describes the rapid recent growth in rural tourism facilities in Spain and attempts to account for the regional variations that exist. The range of activities involved in rural tourism is described and a significant trend towards the development of ‘active’ leisure pursuits in rural areas is identified. This clearly implies a major change in the use of the countryside, albeit in specific locations, but therefore calls into question the assertion of some scholars that rural restructuring is not a feature of contemporary Spain. In assessing the wider impact of rural tourism policies as part of overall rural development, however, it is clear that the main beneficiaries are not necessarily local residents. Copyright © 2004 John Wiley & Sons, Ltd.
Rural tourism development in the USA
Authors: Gartner William C. 
Published: May 2004

AbstractRural tourism has been a subject of study since the early days of tourism scholarship. Most of tourism's deleterious impacts were identified from studies conducted in rural settings. It is only recently, however, that rural tourism has become a special focus of study, dissimilar enough from urban tourism, to be a study subject unto itself.This paper reviews some of the history of rural tourism development in North America with most of the attention paid to the USA's experience, with some examples from Canada. The reason for this is the huge economic difference between the two countries with respect to tourism flows and impacts. In reviewing the history of rural development in the USA, the argument is made that most developments are unplanned and result from market and economic forces that have greatly transformed the American rural landscape. A review of these transformational forces is provided. It is also shown that rural destinations are used, primarily, by local tourists and do not, with few exceptions, cater to an international clientele.After the historical perspective is presented an argument is made that current rural tourism development practices rely on an old paradigm, which is to use local attributes as the primary basis for development and marketing strategies. This has led, in recent years, to a great deal of development attention being paid to the cultural/heritage attributes of a place. Using research conducted in the state of Minnesota on highway travellers and tourists to rural destinations, a new way to look at actual and potential visitors is offered. Instead of an attribute‐specific development approach, a benefits‐based model is suggested as a different way to position rural tourism destinations. Copyright © 2004 John Wiley & Sons, Ltd.
Sustainable leisure life modes and rural welfare economy. The case of the Randers Fjord area, Denmark
Authors: Hjalager Anne‐Mette 
Published: May 2004

AbstractAs increasing attention has been paid to rural tourism as a specific form of tourism development, so too has the scope of research into tourism in rural areas become more diverse. Typically, studies focus primarily upon the economic developmental contribution of rural tourism, although a significant amount of work has been undertaken on the consequences of rural tourism development and attitudes/motivations on the part of visitors and/or local communities. However, no attempt has yet been made to integrate studies of both visitors and local communities within the framework of rural tourism development policy.The purpose of this paper is to address this gap in the literature. Drawing on a study of tourism in the Randers Fjord, a relatively underdeveloped area of rural Denmark, it identifies and analyses three groups of tourists characterised by life modes: (i) traditionalists, (ii) peace seekers and (iii) adventurers. In each case, expectations, behaviour and future needs are revealed through qualitative interviews. The predominant (traditionalist) life mode of tourists, it is argued, closely matches that of the area's residents. This, the paper suggests, presents significant barriers to the development and enhancement of tourism, as do the prevailing economic structures and employment patterns. Thus, tourism development policy should take into account both tourists' and locals' life modes in order to progress towards sustainable rural tourism development. Copyright © 2004 John Wiley & Sons, Ltd.
Rural tourism — meeting the challenges of the new South Africa
Authors: Briedenhann Jennifer , Wickens Eugenia 
Published: May 2004

AbstractRural tourism in South Africa has undergone fundamental change since the advent of political democracy in 1995. Previously perceived as a ‘white man's thing’, rural tourism is increasingly finding a home amongst South Africa's formerly marginalised rural communities. The country has considerable potential in attracting tourists in search of new, exciting experiences in areas of unexploited natural beauty and rich cultural resources. The concept of rural tourism has mushroomed to include adventure tourism activities, cultural tourism and, lately, a new phenomenon in rural communities known as ‘township tourism’. There are, however, substantial challenges to be overcome if the rural tourism sector is to achieve its goals. These include a lack of capacity at local government level, the difficulties involved in operationalising community‐based rural tourism and the dearth of entrepreneurial expertise, management skills and capital with which to expand the rural tourism infrastructure. Copyright © 2004 John Wiley & Sons, Ltd.
Thermotropic Liquid Crystals of Main‐Chain Polyesters having a Mesogenic 4,4′‐Biphenyldicarboxylate Unit, 14
Authors: Osada Kensuke , Koike Masao , Tagawa Hirotaka , Tokita Masatoshi , Watanabe Junji 
Published: May 2004

AbstractSummary: Anisotropy in molecular motions of a glassy smectic CA (SmCA) liquid crystal of a main‐chain BB‐5(3‐Me) polyester was examined by dynamic mechanical analysis (DMA) for fibrous monodomain samples with two distinct orientations of smectic layers perpendicular and parallel to the fiber axis. The α‐process attributed to micro‐Brownian motion of the polymer on the glass transition shows clear anisotropy explainable by the nature of the smectic layer structure. Time‐temperature superposition is applicable to the α‐process, so that the frequency of the micro‐Brownian motion in the SmCA phase can be estimated despite the narrow frequency range in DMA. The results suggest that the decoupling of the molecular motions in two characteristic directions are parallel and perpendicular to the layer. The amplitude of the micro‐Brownian motion in the layer normal direction is 3 times smaller than that in the layer direction, and the frequency in the layer normal direction is 2.5 times higher than that in the layer direction.Illustration of molecular packing structures: fiber A (left side) and fiber B (right side) with the orientations of polymers parallel and perpendicular to the fiber, respectively.imageIllustration of molecular packing structures: fiber A (left side) and fiber B (right side) with the orientations of polymers parallel and perpendicular to the fiber, respectively.
A Model Study of Ti(OBu)4 Catalyzed Reactions during Reactive Blending of Polyethylene (PE) and Poly(ethylene terephthalate) (PET)
Authors: Coltelli Maria‐Beatrice , Savi Stefania , Della Maggiore Irene , Liuzzo Vincenzo , Aglietto Mauro , Ciardelli Francesco 
Published: May 2004

AbstractSummary: The effect of metal catalysts in promoting the formation of the comb copolymer between a very low density polyethylene (VLDPE) grafted with diethyl maleate and PET has been studied in this paper following a model study based on low molecular weight molecules resembling the local structure of the reactive groups in the reference macromolecules. Ti(OBu)4 was used as the catalyst and the reactions were carried out under the same conditions as in the case of the macromolecules species. The model mixtures have been analyzed by FT‐IR, 1H and 13C NMR spectroscopy, thermogravimetric analysis (TGA) and GC‐MS and evidence of the degradation of ester bonds, deactivation of hydroxyl terminals of PET and the possible crosslinking of functionalized polyolefin have been observed. The molecular model process agrees with results obtained for the macromolecular system blending PET and VLDPE grafted with diethyl maleate in a Brabender mixer in the presence of Ti(OBu)4, as evaluated by mixer torque values and selective extraction results. Therefore, the present model study allows us to both obtain information about reaction mechanism in the complex melt biphasic system and to suggest new strategies to optimize the process.Brabender torque/time graphics of PET in presence of different amounts of Ti(OBu)4.imageBrabender torque/time graphics of PET in presence of different amounts of Ti(OBu)4.
Deactivation Kinetics of Metallocene‐Catalyzed Ethene Polymerization at High Temperature and Elevated Pressure
Authors: Dornik Hans Peter , Luft Gerhard , Rau Alexander , Wieczorek Thomas 
Published: May 2004

AbstractSummary: The kinetics of ethene polymerization with metallocene/[Me2PhNH]+[B(C6F5)4]−/AliBu3 (ternary systems) and metallocene/methylaluminoxan (MAO) systems respectively has been investigated at 100–140 °C and 7 MPa. Overall, eight different unbridged and ansa‐metallocenes were tested. The effect of ligand structure, cocatalyst and catalyst concentration on the thermostability and the activation energy of deactivation were studied. Deactivation with respect to the catalyst concentration followed a first order reaction. The half‐life as well as the activation energy of the ternary systems depended strongly on ligand structure while the ligand structure of MAO‐activated metallocenes merely influenced the half‐life. The half‐life associated with MAO activation is approximately twice as high as that in ternary activation. Based on these results, conclusions about the deactivation reactions have been drawn.Influence of catalyst concentration on deactivation.imageInfluence of catalyst concentration on deactivation.
Co‐Micellization Investigated by Pulsed Field Gradient‐NMR Spectroscopy
Authors: Gröger Stefan , Geschke Dieter , Kärger Jörg , Stallmach Frank , Koňák Čestmír 
Published: May 2004

AbstractSummary: Pulse field gradient‐NMR (PFG‐NMR) spectroscopy is determined to be a more suitable method for the investigation of self‐association processes in multi‐component (co)polymer systems than light scattering methods. Here the co‐micellization of mixtures of the diblock copolymer polystyrene‐block‐(hydrogenated polyisoprene) (PS‐HPI) and the triblock copolymer polystyrene‐block‐(hydrogenated polybutadiene)‐block‐polystyrene (PS‐HPB‐PS) in decane is investigated by PFG‐NMR spectroscopy and the results compared to those experimentally determined by static (SLS) and dynamic (DLS) light scattering. As expected, diffusion coefficients determined by PFG‐NMR spectroscopy are systematically lower than those from DLS. The PFG‐NMR measurements provided higher values of c(X)/ctot than the model calculations, illustrating that the basic assumption used in the calculations, i.e., that the number concentration of co‐micelles in mixed solutions follows the dilution with a triblock copolymer solution, 1 − X, is not fully valid at high X (weight fraction of PS‐HPB) values.Comparison of PFG‐NMR spectroscopy and SLS (c/ctot = equilibrium concentration of free PS‐HPB‐PS over the total concentration of copolymers in solution, X = weight fraction of PS‐HPB).magnified imageComparison of PFG‐NMR spectroscopy and SLS (c/ctot = equilibrium concentration of free PS‐HPB‐PS over the total concentration of copolymers in solution, X = weight fraction of PS‐HPB).
Structure Formation During the Isothermal Crystallization of an Oriented Blend of Isotactic Polystyrene with Poly(2,6‐dimethyl‐1,4‐phenylene oxide)
Authors: Dikshit Asok Kumar , Kaito Akira 
Published: May 2004

AbstractSummary: Isothermal crystallization of an oriented blend of isotactic polystyrene (iPS) with poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) was studied by in situ polarized FT‐IR spectroscopy and wide‐angle X‐ray diffraction. The structural organization during the oriented crystallization consists of three stages. The first stage is the orientation relaxation of molecular chains of iPS and PPO, the degree of orientation of iPS increases in the second stage, and the oriented chains of iPS crystallize in the third stage.magnified image
Mimetics of Eggshell Membrane Protein Fibers by Electrospinning
Authors: Yi Feng , Guo Zhao‐Xia , Hu Ping , Fang Zhuang‐Xi , Yu Jian , Li Qiang 
Published: May 2004

AbstractSummary: Mimetics of eggshell membrane protein fibers have been obtained with an electrospinning technique based on soluble eggshell membrane protein (SEP) prepared previously. Poly(ethylene oxide), a biocompatible and water soluble polymer, is used to improve the processability of SEP. Blends of SEP/PEO aqueous solutions were electrospun. The diameters of the fibers are 0.3–20 μm depending on the concentration of the solution and the proportion of SEP/PEO. Two “cross‐linking” methods are investigated in order to improve the anti‐water property of the fibers.Scanning electron micrograph of electrospun fibers.magnified imageScanning electron micrograph of electrospun fibers.