bluuebunny/crossref_metadata_2025_split huggingface dataset:
NMR diffusion measurements of strong signals: the PGSE‐Q‐switch experiment
Authors: Price William S. , Wälchli Markus 
Published: November 2002

AbstractNMR diffusion measurements of samples with strong resonances are particularly problematic owing to the effects of radiation damping and become even more difficult at higher static fields and with more sensitive probes. Here, a new PGSE sequence incorporating Q‐switching that totally removes the effects of radiation damping is presented. The sequence affords the possibility of performing diffusion measurements of concentrated samples at normal sample volumes at high field, and thus has particular relevance for gradient calibration, diffusive diffraction and LC–NMR experiments. Further, because the relaxation behaviour of all of the species is unaffected by radiation damping, the incorporation of sophisticated sequence elements is facilitated and data analysis is simplified. The new sequence is demonstrated on a sample containing 90% water and 1% ethanol. Copyright © 2002 John Wiley & Sons, Ltd.
Use of 1H NMR‐determined diffusion coefficients to characterize lipoprotein fractions in human blood plasma
Authors: Liu Maili , Tang Huiru , Nicholson Jeremy K. , Lindon John C. 
Published: November 2002

AbstractThe 1H NMR spectra of human blood plasma show, inter alia, prominent resonances from the methyl and methylene groups of the fatty acyl chains from the triglycerides, phospholipids and cholesteryl esters of lipoproteins. Each band shows some degree of peak resolution due to chemical shift differences between the lipoprotein fractions, namely very low‐density lipoprotein (VLDL), low‐density lipoprotein (LDL) and high‐density lipoprotein (HDL). In order to assign resonances within the NMR bands to individual lipoproteins, previous studies relied upon the measurement of pure fractions obtained by ultracentrifugation. Here a new approach was used where the lipoprotein peaks in the NMR spectrum were deconvolved mathematically and the area of each sub‐peak was monitored using an NMR pulse sequence to yield the diffusion coefficient relating to each sub‐peak and hence to each type of lipoprotein. The validity of the deconvolution results was confirmed by comparison of 1H NMR spectra measured at 600 and 800 MHz. The diffusion coefficient is directly related to the hydrodynamic radius of the particle and hence provides an unambiguous assignment. The derived diffusion coefficients of the lipoprotein fractions therefore provide a direct assignment of the NMR bands and also give a measure of lipoprotein particle size, the results being in agreement with those from conventional measurements. Copyright © 2002 John Wiley & Sons, Ltd.
Translational diffusion measured by PFG‐NMR on full length and fragments of the Alzheimer Aβ(1–40) peptide. Determination of hydrodynamic radii of random coil peptides of varying length
Authors: Danielsson Jens , Jarvet Jüri , Damberg Peter , Gräslund Astrid 
Published: November 2002

AbstractPFG‐NMR methods were used to measure the translational diffusion coefficients for the Aβ peptide involved in Alzheimer's disease and also for a series of fragments of this peptide. The peptides ranged from a pentamer to the full length Aβ(1–40). They were studied at 25° C and physiological pH in aqueous solution. The measured diffusion coefficients, including those of known monomeric peptides, were fitted without systematic deviations to a scaling law function of the molecular mass. We concluded that under these conditions Aβ(1–40) is in monomeric form. From the diffusion coefficient data, hydrodynamic radii rH were evaluated for the peptides. When combining our results on non‐ or weakly structured peptides with previously reported results on denatured proteins, we found that the hydrodynamic radii for the combined dataset could be well described by the same scaling law relating them to the molecular weight. The same law would even encompass data on single amino acids and di‐ and tripeptides measured by classical methods. From the above‐mentioned experimental data, scaling law parameters were determined. The relation between the measured hydrodynamic radius (rH) and the molecular weight of the polypeptide chain (Mr) for amino acids, peptides and denatured proteins is rH = 0.27Mr0.50 Å. There is a remarkably good fit to this function for the measured hydrodynamic radii in a large range, almost three orders of magnitude, of molecular weights. The numerical value of the exponent, 0.5, is an indication that these polymers behave as Gaussian chains. Copyright © 2002 John Wiley & Sons, Ltd.
Composite concrete‐timber structures
Authors: Ceccotti Ario 
Published: November 2002

AbstractComposite concrete–timber building and bridge structures are gaining in importance throughout the world. The approach is to pour fresh concrete over the timber. Mechanical linkage between hardened concrete and timber is provided through keyed indentations in the timber or various sorts of mechanical fasteners inserted in the timber before the concrete is poured. The technique is commented on from research and design points of view.
Immediate and delayed VEGF‐mediated NO synthesis in endothelial cells: Role of PI3K, PKC and PLC pathways
Authors: Gélinas David S , Bernatchez Pascal N , Rollin Simon , Bazan Nicolas G , Sirois Martin G 
Published: November 2002

The mechanism(s) by which vascular endothelial growth factor (VEGF) induces endothelial nitric oxide synthase (eNOS) activation remain(s) unclear up to a certain extent. Therefore, we sought to evaluate the contribution of numerous pathways in VEGF‐induced nitric oxide (NO) synthesis by measuring cGMP production. In addition, as VEGF induces the synthesis of NO and platelet‐activating factor (PAF), we wanted to assess if the induction of PAF and NO is contributing to the synthesis of each other.
Herein, we show that a treatment of endothelial cells with a phospholipase C (PLC) inhibitor (U73122), a calmodulin antagonist (W‐7) or with intracellular calcium chelators (EGTA/AM, BAPTA/AM) prevented VEGF‐mediated eNOS Ser1177‐phosphorylation and NO synthesis measured by cGMP production.
Pretreatment with phosphatidylinositol 3‐kinase (PI3K) (Wortmannin, LY294002) or protein kinase C (PKC) (GF109203X, Ro318220) inhibitors attenuated eNOS Ser1177‐phosphorylation mediated by VEGF, but did not alter immediate (0–10 min) cGMP synthesis induced by VEGF, but abrogated by up to 84% the delayed (10–30 min) cGMP synthesis.
Pretreatment with PAF synthesis inhibitors or with PAF receptor antagonists did not abrogate neither eNOS Ser1177‐phosphorylation nor cGMP synthesis mediated by VEGF.
In conclusion, VEGF induces an immediate cGMP synthesis through the PLC‐Ca2+/CaM pathway, and that the induction of delayed cGMP synthesis implies Akt and PKC activity.

British Journal of Pharmacology (2002) 137, 1021–1030. doi:10.1038/sj.bjp.0704956
Rol percibido en la relación del profesional de la salud con el paciente y cumplimiento terapéutico
Authors: Nouvilas Encarnación 
Published: November 2002

Dentro del estudio de los procesos sociocognitivos implicados en la conducta de salud, el objetivo de este estudio es obtener la percepción de rol de las personas implicadas en la relación del profesional de la salud con el paciente. Así como su asociación con el cumplimiento terapéutico del paciente. Cien pacientes de hipertensión arterial esencial y cien profesionales de la salud (médicos y de enfermería) respondieron a los cuestionarios especialmente elaborados para este trabajo. El cumplimiento terapéutico lo valoramos mediante una medida combinada de autoinforme y consecución de los objetivos terapéuticos. Los resultados mostraron que el rol del paciente podría evaluarse por los profesionales sanitarios en función de tres dimensiones fundamentales (obediencia/resistencia hacia la asistencia sanitaria; confianza/desconfianza hacia los profesionales sanitarios y cumplimiento/incumplimiento hacia los tratamientos terapéuticos). El rol de médico percibido por los pacientes se definió de forma más amplia y exigente que el rol de la enfermera. Y por último, observamos diferencias entre los pacientes cumplidores y los incumplidores respecto a algunas características atribuidas al rol del médico.
Burnout y engagement. Relación con el desempeño, madurez profesional y tendencia al abandono de los estudiantes
Authors: Manzano Guadalupe 
Published: November 2002

El objetivo de este trabajo es analizar el burnout y su constructo hipotético opuesto “el engagement” en estudiantes universitarios. Además de determinar qué variables influyen en uno u otro, y profundizar en las relaciones entre estos dos constructos, estudiamos hasta qué punto pueden explicar, junto a algunas variables demográficas, el comportamiento de los estudiantes respectoa tres variablesps icosociales: desempeño, madurez profesional y tendencia al abandon. La muestra esta compuesta por 1284 individuos (33,2% hombres y 66,7% mujeres) que cursan la Licenciatura en Administración y Dirección de Empresas en la Facultad de Ciencias Económicas y Empresariales de la Universidad del País Vasco. Entre los resultados hallados, cabe destacar: 1. -La relación negativa entre las escalas del burnout agotamiento emocional y cinismo y las del engagement vigor, dedicación y absorción; así como una relación positiva entre la competencia percibida (burnout) y las tres escalas del engagement. 2. -La existencia de diferencias significativasen las dimensiones de burnout y engagement en función del sexo. 3. -La edad es el único factor que se repite en la explicación de las tres variables psicosociales. Las escalas del burnout y engagement contribuyen, de forma diferente, a la explicación de cada una de dichas variables.
Niveles de análisis en el estudio de liderazgo carismático
Authors: López-Zafra Esther , Morales J. Francisco 
Published: November 2002

En este artículo revisamos brevemente el concepto de niveles de análisis y nos centramos en su aplicación al estudio de Liderazgo Carismático ya que este enfoque apenas si se ha tenido en cuenta y es prácticamente nulo su empleo en España. Desde nuestro punto de vista consideramos que Carisma es un fenómeno que se incardina en el grupo, ya que existen diferencias significativas entre grupos de trabajo cuyo líder es carismático y aquellos otros cuyo líder no lo es. Esto nos hace pensar que debe explicarse en el nivel grupal. Una técnica que sirve para comprobar el nivel de análisis adecuado es el denominado «análisis intra-entre»» (A.I.E. o W.A.B.A. Within-and Between entities analysis) que explicamos brevemente en este artículo. Para realizar nuestro estudio hemos administrado el M.L.Q. (Multifactor Leadership Questionnaire) junto con otras escalas en 39 unidades de producción (N total=199). Los resultados favorecen nuestra hipótesis en la dirección entregrupos en la relación entre Carisma y algunas variables. Por el contrario, otras relaciones se explican en el nivel intragrupo. Al final, ofrecemos una discusión de porqué se producen estos resultados y sus implicaciones.
Tendencias emergentes en el comportamiento de ocio: el ocio serio y su evaluación
Authors: Codina Núria 
Published: November 2002

Se considera la expresión personal como una tendencia de comportamiento asociada a los cambios que experimentan las sociedades industriales avanzadas. Se analiza esta tendencia en el ámbito del ocio y, a falta de planteamientos más específicos, se muestra que ésta puede explicarse a partir de una teoría formulada recientemente con otros objetivos, la del ocio serio de Stebbins. Con base en ésta, observamos que numerosas actividades pueden darse como ocios serios y que el actual comportamiento en el ocio globalmente tiende a colorearse de cierto carácter serio, de manera que presenta el aspecto borroso de los sistemas complejos. También observamos que se valora positivamente el ocio serio a partir de su estudio en el “aquí y ahora” y a través de la percepción subjetiva. Cuestionamos estas valoraciones mostrando que para avanzar en el conocimiento y evaluación psicosocial del ocio, especialmente del ocio serio, debe considerarse el carácter multiforme, ambivalente y transitorio del fenómeno en relación con el contexto sociocultural, así como las variables analíticas del ocio. Finalmente, explicamos que el consumo de un ocio serio puede derivar en un ocio consumidor, con consecuencias negativas para la persona y su entorno.
Self epitopes shared between human skeletal myosin and Streptococcus pyogenes M5 protein are targets of immune responses in active juvenile dermatomyositis
Authors: Massa Margherita , Costouros Nick , Mazzoli Federica , De Benedetti Fabrizio , La Cava Antonio , Le Tho , de Kleer Isme , Ravelli Angelo , Liotta Margaret , Roord Sarah , Berry Charles , Pachman Lauren M. , Martini Alberto , Albani Salvatore 
Published: November 2002

AbstractObjectiveTo identify self T cell epitopes associated with proinflammatory immune responses and clinically active juvenile dermatomyositis (juvenile DM). The target of our search for relevant epitopes was represented by amino acid sequences shared between human skeletal myosin and Streptococcus pyogenes M5 protein. The long‐term objective of the project is to identify suitable targets for immunotherapy of the disease.MethodsWe used computerized algorithms to identify putative agretopes on both the human myosin and Streptococcus M5 proteins. Direct binding assays for homolog peptides were used to confirm such predictions. Antigenicity and functional cross‐reactivity were evaluated by cytotoxicity assays and by measurement of cytokine levels. Specific T cells were isolated by T cell capture, and T cell receptor (TCR) Vβ gene usage was identified by reverse transcriptase–polymerase chain reaction.ResultsWe identified peptides that are targets of disease‐specific cytotoxic T cell responses. T cell reactivity against the self peptides correlates with clinical signs of early, active myositis. Such reactivity is accompanied by production of proinflammatory cytokines, which may contribute to the damage. T cell cross‐recognition of bacterial and human homologs was shown functionally as well as by sorting peptide‐specific T cells and identifying oligoclonal and largely overlapping TCR Vβ gene usage.ConclusionThese findings represent the first identification of a self epitope in juvenile DM, providing a potential candidate for antigen‐specific immune therapy.
Risk factors for progressive cartilage loss in the knee
Authors: Biswal Sandip , Hastie Trevor , Andriacchi Thomas P. , Bergman Gabrielle A. , Dillingham Michael F. , Lang Philipp 
Published: November 2002

AbstractObjectiveTo evaluate the rate of progression of cartilage loss in the knee joint using magnetic resonance imaging (MRI) and to evaluate potential risk factors for more rapid cartilage loss.MethodsWe evaluated baseline and followup MRIs of the knees in 43 patients (minimum time interval of 1 year, mean 1.8 years, range 52–285 weeks). Cartilage loss was graded in the anterior, central, and posterior regions of the medial and lateral knee compartments. Knee joints were also evaluated for other pathology. Data were analyzed using analysis of variance models.ResultsPatients who had sustained meniscal tears showed a higher average rate of progression of cartilage loss (22%) than that seen in those who had intact menisci (14.9%) (P ≤ 0.018). Anterior cruciate ligament (ACL) tears had a borderline significant influence (P ≤ 0.06) on the progression of cartilage pathology. Lesions located in the central region of the medial compartment were more likely to progress to more advanced cartilage pathology (progression rate 28%; P ≤ 0.003) than lesions in the anterior (19%; P ≤ 0.564) and posterior (17%; P ≤ 0.957) regions or lesions located in the lateral compartment (average progression rate 15%; P ≤ 0.707). Lesions located in the anterior region of the lateral compartment showed less progression of cartilage degradation (6%; P ≤ 0.001). No specific grade of lesion identified at baseline had a predilection for more rapid cartilage loss (P ≤ 0.93).ConclusionMRI can detect interval cartilage loss in patients over a short period (<2 years). The presence of meniscal and ACL tears was associated with more rapid cartilage loss. Cartilage lesions located in the central region of the medial compartment showed more rapid progression of cartilage loss than cartilage lesions in the anterior and posterior portions of the medial compartment. The findings in this study suggest that patients entering clinical trials investigating antiarthritis regimens may need to be randomized based on location of the lesion.
Migration of CX3CR1‐positive T cells producing type 1 cytokines and cytotoxic molecules into the synovium of patients with rheumatoid arthritis
Authors: Nanki Toshihiro , Imai Toshio , Nagasaka Kenji , Urasaki Yasuyo , Nonomura Yoshinori , Taniguchi Ken , Hayashida Kenji , Hasegawa Jun , Yoshie Osamu , Miyasaka Nobuyuki 
Published: November 2002

AbstractObjectiveRheumatoid arthritis (RA) is characterized by chronic inflammation of multiple joints. Large numbers of T cells, which produce type 1 cytokines, infiltrate into RA synovium. Chemokines and chemokine receptors are considered to contribute to the T cell infiltration. In this study, we examined the role of CX3CL1/fractalkine and its receptor CX3C chemokine receptor 1 (CX3CR1) in the T cell migration into RA synovium.MethodsUsing flow cytometry, immunohistochemistry, and reverse transcription–polymerase chain reaction, we analyzed CX3CR1 expression by peripheral blood and synovial T cells, and CX3CL1 expression in synovium from patients with RA. Cytokine and cytotoxic molecule expression by CX3CR1‐positive T cells was analyzed by flow cytometry.ResultsCX3CR1 expression by peripheral CD4+ and CD8+ T cells was up‐regulated in RA patients. The peripheral CD4+ and CD8+ T cells expressing CX3CR1 predominantly produced interferon‐γ and tumor necrosis factor α, and expressed cytotoxic molecules such as granzyme A and perforin. Furthermore, CX3CR1+,CD3+ T cells infiltrated into RA synovium. CX3CL1, the unique ligand of CX3CR1, was expressed by endothelial cells and synoviocytes in RA synovium, but not in osteoarthritis synovium.ConclusionOur findings suggest that the interactions of CX3CL1 and CX3CR1 might contribute to the accumulation of CX3CR1+ T cells expressing type 1 cytokines and possessing cytotoxic granules in RA synovium.
Artefacts and pitfalls in diffusion measurements by NMR
Authors: Sørland Geir Humborstad , Aksnes Dagfinn 
Published: November 2002

AbstractWhen applying pulsed field gradient (PFG) NMR experiments to determine the molecular mobility characterized by the diffusion coefficient, it is crucial to have control over all experimental parameters that may affect the performance of the diffusion experiment. This could be diffusion measurement in the presence of magnetic field transients, internal magnetic field gradients, either constant or spatially varying, convection, mechanical vibrations, or in the presence of physical restrictions affecting the diffusion propagator. The effect of these parameters on the diffusion experiment is discussed and visualized. It is also outlined how to minimize their influence on the measured diffusivity that is extracted from the PFG‐NMR experiment. For an expanded and more general treatment we refer to the excellent reviews by Dr William S. Price (Concepts Magn. Reson. 1997; 9: 299; 1998; 10: 197) and the references therein. Copyright © 2002 John Wiley & Sons, Ltd.
Scope of droplet size measurements in food emulsions by pulsed field gradient NMR at low field
Authors: van Duynhoven J. P. M. , Goudappel G. J. W. , van Dalen G. , van Bruggen P. C. , Blonk J. C. G. , Eijkelenboom A. P. A. M. 
Published: November 2002

AbstractLow‐field NMR instrumentation offers a user‐friendly and cost‐effective means for assessment of water and oil droplet size measurements in food emulsions. Examples are given of major food application areas, and these are supported with validation data in terms of precision and equivalence to other methods. The NMR method gives the same results as other techniques, such as microscopy, laser diffraction and electric sensing, but with similar or better precision. NMR distinguishes itself by a simple and non‐perturbing sample preparation procedure (in addition to the aforementioned advantages). For reliable results, the NMR parameters should be properly chosen and adjusted. A survey is given of experimental NMR parameters than can have an impact on the performance of water and oil droplet size determination. Copyright © 2002 John Wiley & Sons, Ltd.
NMR methods applied to anisotropic diffusion
Authors: Furó István , Dvinskikh Sergey V. 
Published: November 2002

AbstractThe methodology of NMR experiments intended to measure anisotropic diffusion is reviewed. Experiments of this kind preferably require oriented samples and/or orientation‐dependent spin coupling and/or magnetic field gradients in different directions. One strategy of diffusion experiments in anisotropic systems with broad NMR lines employs line narrowing techniques, thereby allowing for efficient gradient encoding/decoding. Depending on the nuclei, spin couplings and samples, the preferred methods vary from decoupling through echo techniques to magic angle sample orientation and spinning. Another avenue to efficient gradient encoding/decoding is through very strong magnetic field gradients. Either way, anisotropic diffusion reveals new structural features as illustrated by a few selected examples in liquid crystals and in biological tissues. Copyright © 2002 John Wiley & Sons, Ltd.
Performance of timber buildings under seismic load. Part 1: experimental studies
Authors: Lam Frank , Filiatrault Andre , Kawai Naohito , Nakajima Shiro , Yamaguchi Nobuyoshi 
Published: November 2002

AbstractSeveral comprehensive research programmes were initiated recently in North America and Japan to improve our understanding of the seismic performance of timber buildings. A large database of experimental results and innovative modelling approaches were developed in these programmes. This paper is Part 1 of a two‐part series. It provides brief summaries of the performance of timber structures in the Northridge and Kobe earthquakes, and reports highlights from the state‐of‐art North American and Japanese experimental research activities. Part 2 of the paper will focus on the modelling aspect of this interesting and important problem.