bluuebunny/crossref_metadata_2025_split huggingface dataset:
More data on major depression as an antecedent risk factor for first onset of chronic back pain
Authors: CURRIE SHAWN R. , WANG JIANLI 
Published: August 2005

Background. Few epidemiological studies have examined the temporal relationship between chronic pain and depression using longitudinal data. In the present study, we examined major depression as both an antecedent risk factor and consequence of chronic back pain (CBP) in the general population.Method. Data on 9909 pain-free individuals 15 years and older with no history of back problems were drawn from cycle 1 of the National Population Health Survey and followed up 24 months later. Major depression was assessed using a structured diagnostic interview.Results. At cycle 2, the rate of new cases of CBP in persons who were depressed at cycle 1 was 3·6% compared to 1·1% in non-depressed persons. Compared to pain-free individuals, new cases of CBP were more likely to perceive their health status as poor or fair at cycle 1, were less likely to be working, reported more chronic health problems, and sustained a back or neck injury in the preceding 12 months. After controlling for other factors, pain-free individuals diagnosed as major depressed at cycle 1 were almost three times more likely (OR 2·9, 95% CI 1·2–7·0) to develop CBP at cycle 2.Conclusions. Consistent with other longitudinal studies major depression increases the risk of developing future chronic pain. The causal mechanism linking these conditions is unknown however depression may represent a modifiable risk factor in the development of CBP.
Genetic and environmental influences on illicit drug use and tobacco use across birth cohorts
Authors: KENDLER KENNETH S. , GARDNER CHARLES , JACOBSON KRISTEN C. , NEALE MICHAEL C. , PRESCOTT CAROL A. 
Published: August 2005

Background. The prevalence of use of many psychoactive substances has changed considerably in recent years. While genetic factors impact on overall risk for substance use, we know little about whether the etiological importance of these factors differs across birth cohorts. One theory, which postulates that heritability of deviant traits increases in permissive environments, predicts a positive relationship across cohorts between prevalence and heritability of substance use.Method. The lifetime history of use of tobacco, cannabis, cocaine, sedatives and stimulants were assessed in 4826 twins from male–male and female–female pairs born in Virginia from 1934 to 1974. Using empirical methods based on prevalence by birth year, these twins were divided into three cohorts for each substance (e.g. for cannabis 1934–1953, 1954–1968 and 1969–1974). Structural equation modeling was performed using the Mx software package.Results. Prevalence rates for psychoactive substance use differed substantially across cohorts, most markedly for cocaine, sedatives and stimulants, which were highest in the 1958–1963 cohort. However, for all substances, the best-fit model constrained estimates of the etiological role of genetic and environmental risk factors to be equal across both sex and cohort.Conclusions. We found no evidence in this sample for any systematic relationship between heritability and prevalence of psychoactive substance use – which should be a rough index of drug availability and/or acceptability. This sample had reasonable power to detect large changes in heritability across cohorts and at least moderate power to detect relatively small changes.
The application of fracture mechanics to crack propagation in dry soil
Authors: HALLETT P.D. , DEXTER A.R. , SEVILLE J.P.K. 
Published: August 2005

SummaryThe application of fracture mechanics to dry soil has been investigated. Discs moulded from sand and kaolinite pastes, into which artificial tension cracks were introduced, were fractured using the indirect tension technique. The basic linear elastic fracture mechanics (LEFM) approach was found inadequate to describe the observed relation between the imposed flaw size and the failure stress. Fracture mechanics have been extended to dry soil by adding a crack length increment, Δc, to the imposed flaw size, c, to account for energy dissipation by processes other than the creation of new surfaces. This increment seems to represent the effective size of a ‘process zone’ ahead of the crack tip in which energy is dissipated by micro‐cracking and internal friction. Further experiments done using specimens containing two collinear cracks separated by a variable distance and using samples of different size showed that the two cracks behaved effectively as one for separation distances less than about Δc. For specimen sizes much bigger than Δc fracture testing was found to be scale‐invariant for geometrically similar specimens.
Modelling the solid–solution distributions of protons, aluminium, base cations and humic substances in acid soils
Authors: TIPPING E. , BERGGREN D. , MULDER J. , WOOF C. 
Published: August 2005

Summary wham, an equilibrium chemical model for soils, waters and sediments, centred on a discrete‐site/ electrostatic model of humic substances (HS), has been used to analysae batch titration data for organic and mineral horizons of acid soils. In most cases, tolerable fits were obtained by optimizing the soil contents of HS and aluminium, while keeping the model parameters (site densities, equilibrium constants, electrostatic terms) fixed. The optimized contents agreed reasonably with those estimated by chemical extraction. For some mineral soil samples, low in HS and high in aluminium, fitting of the titration data was improved by assuming the formation and dissolution of A1(OH)3 and adjusting its solubility product. Solid‐solution distributions of base cations (Na+, Mg2+, K+, Ca2+, NH+4) could be explained by non‐specific counterion accumulation, with a small degree of selectivity. The WHAM sub‐model for fulvic acid sorption accounted approximately for observed aqueous‐phase concentrations of organic carbon and organically‐complexed aluminium.
Modelling phosphate‐sorption kinetics in acid soils
Authors: FREESE D. , VAN RIEMSDIJK W.H. , VAN DER ZEE S.E.A.T.M. 
Published: August 2005

SummaryA model of P‐sorption kinetics was developed, that accounts for the dependency of reaction rate on concentration, sorbed P content, sorption maximum and time. The sorption phenomena predicted by the model agree with available observations in the literature. The model was tested with batch experiments for 17 acid top– and subsoils. The experiments revealed a significant correlation between the sorption maximum, Fm, and the sum of amorphous iron and aluminium in soils. Plotting the dimensionless P–sorption ratio, F(c, t)/Fm, which may be interpreted as the fractional saturation of the sorption capacity of a soil, against the natural logarithm of the exposure variable, I, gave S–shaped curves. Different parts of the S–shaped curve can be experimentally assessed, depending on the initial fractional saturation of the P–sorption capacity of soils. Apart from this dependency, one set of parameter values sufficed to describe the sorption kinetics of 10 different sandy top– and subsoils. For non–sandy soils, the parameter values differed and depended on the initial P content. The model enables extrapolation to long times, which is necessary for applications to field conditions.
Equilibrium adsorption of isoproturon on soil and pure clays
Authors: WORRALL F. , PARKER A. , RAE J.E. , JOHNSON A.C. 
Published: August 2005

SummaryThe adsorption of isoproturon on soil and pure clay minerals has been investigated as a means of understanding its mobility in soils. Measured adsorption coefficients are correlated with soil and clay mineral properties.Soil organic matter controlled the adsorption of isoproturon at organic carbon contents exceeding 27 g kg−1, whereas at less than this threshold, clay mineral surfaces appeared to control adsorption. The effect of varying temperature suggests that adsorption of isoproturon is a physical process. From the comparison of the fits of linear, Freundlich, and Langmuir adsorption isotherms to the data, the adsorption is best described as a partition process.
Fate of particulate organic matter in soil aggregates during cultivation
Authors: BESNARD E. , CHENU C. , BALESDENT J. , PUGET P. , ARROUAYS D. 
Published: August 2005

SummaryParticulate organic matter (POM) is a labile fraction of soil organic matter which is thought to be physically protected from biodegradation when within soil aggregates. We have developed a fractionation method to separate POM located outside stable soil macroaggregates (> 200 μm) and microaggregates (50–200 μm) from that within them, and applied it to a cultivation sequence of humic loamy soils. The natural abundance of 13C was used to determine the amounts of POM derived from forest and that derived from crop in the free and occluded fractions. In the forest soil the free and occluded POM fractions had the same composition, morphology and isotopic signature. On cultivation the amounts of POM decreased sharply. The loss of C in the POM from forest was mainly from POM outside the aggregates. The POM occluded within microaggregates was found to turnover slowly. This may be due either to its recalcitrant chemical nature or to its physical protection within microaggregates
Simulating soil deformation using a critical‐state model: II. Soil compaction beneath tyres and tracks
Authors: KIRBY J.M. , BLUNDEN B.G. , TREIN C.R. 
Published: August 2005

SummaryA critical‐state finite element model was used to simulate compaction under single and dual tyres and tracks. The compaction involved deformations at three different scales, from small tyres with a contact area of about 70 cm2 (single tyre) supporting a load of about 50 kg, to large tyres of about 1.2 m2 (dual tyres) supporting a load of about 4500 kg. The predictions were compared with measured values for several different quantities. These included: rut depths; vertical displacement and shear strain: vertical stresses; and, void ratios and precompression stress measured on sampled soil cores. In general, the predictions and measurements agreed reasonably well. However, the agreement between prediction and measurement depended on the precision of measurements, soil disturbance, and the volume of soil involved in a measurement relative to the volume of soil influenced by the tyre or track. This study shows that the critical‐state finite element model is useful, offering insight into the compaction process, the dependence of compaction on soil strength and compressibility, and practical implications for soil management.
CD4+CD25+‐Regulatory T Cells from Mouse to Man
Authors: Wing K. , Suri‐Payer E. , Rudin A. 
Published: August 2005

AbstractImmunological tolerance is one of the fundamental concepts of the immune system. During the past decade, CD4+CD25+‐regulatory T cells have emerged as key players in the development of tolerance to autoantigens as well as to foreign antigens. Still many questions remain illusive regarding the basic properties of CD4+CD25+‐regulatory T cells. This review aims to recapitulate some of the current understandings about the phenotype, function and clinical relevance of murine and human CD4+CD25+‐regulatory T cells.
Dexamethasone Induces IL‐10‐Producing Monocyte‐Derived Dendritic Cells with Durable Immaturity
Authors: Xia C.‐Q. , Peng R. , Beato F. , Clare‐Salzler M. J. 
Published: August 2005

AbstractIt is highly desirable that immature dendritic cells (DC) used for tolerance induction maintain steady immature state with predominant interleukin (IL)‐10 production. In this study, we attempted to develop DC with durable immaturity and other tolerogenic features by using dexamethasone (Dex). We found DC derived from human monocytes in the presence of 10−7 m Dex were negative for CD1a. Compared with control transduced DC (Ctrl‐DC), Dex‐DC expressed lower CD40, CD80 and CD86 but equivalent human leucocyte antigen‐DR. Both immature Dex‐ and Ctrl‐DC did not express CD83. Nevertheless, upon stimulation of lipopolysaccharide (LPS) or CD40 ligand, the expression of CD40, CD80, CD83 and CD86 was upregulated on Ctrl‐DC but not on Dex‐DC. The immaturity of Dex‐DC was durable following Dex removal. Interestingly, Dex‐DC maintained production of large amount of IL‐10 and little IL‐12 five days after Dex removed. Further study indicated that high‐level IL‐10 production by Dex‐DC was associated with high‐level phosphorylation of extracellular signal‐regulated kinase (ERK) as blockade of this enzyme markedly attenuated IL‐10 production. Furthermore, Dex‐DC sustained the capability of high phosphorylation of ERK and IL‐10 production 5 days after Dex removal. In addition, Dex‐DC had significantly lower activity in stimulating T‐cell proliferation. Neutralization of IL‐10, to some extent, promoted DC maturation activated by LPS, as well as T‐cell stimulatory activity of Dex‐DC. The above findings suggest that IL‐10‐producing Dex‐DC with durable immaturity are potentially useful for induction of immune tolerance.
Long‐term follow up results of intraductal papillary mucinous tumors of pancreas
Authors: LEE SUN‐YOUNG , LEE KYU TAEK , LEE JONG KYUN , JEON YONG HWAN , CHOI DONGIL , LIM JAE HOON , HEO JIN SEOK , CHOI SEONG HO , JANG KEE‐TAEK , PAIK SEUNG WOON , RHEE JONG CHUL 
Published: August 2005

AbstractBackground and Aim:  Intraductal papillary mucinous tumor (IPMT) of the pancreas can be divided into three clinically distinct subtypes: main duct type, branch duct type and mixed type. Although it has been reported that the branch duct type IPMT is less invasive than the main duct type IPMT, we experienced a number of branch duct type IPMT having a poor prognosis. In the present study we surveyed the survival and recurrence rates according to the subtypes.Methods:  Sixty‐seven IPMT cases were studied to investigate clinical behavior according to the duct types. Diagnostic findings and late results of treatment were reviewed in 27 cases of the main duct type IPMT and in 35 cases of the branch duct type IPMT.Results:  There was no statistically significant difference in the survival analysis between the main duct type IPMT and the branch duct type IPMT (P = 0.93). Seven patients (25.9%) died among the main duct type IPMT while six patients (17.1%) died among the branch duct type IPMT (P = 0.36). Tumor recurrence was noticed in four patients (18.1%) among 22 operated main duct type IPMT and in two patients (6.9%) among 29 operated branch duct type IPMT (P = 0.35).Conclusion:  The long‐term follow up result of the branch duct type IPMT is similar to that of the main duct type IPMT. Therefore, it is not safe just to monitor the branch duct type IPMT without operation. Surgery, whenever possible, is clearly the gold standard for treatment of IPMT, regardless of duct type.
Assessing Fire Potential in a Brazilian Savanna Nature Reserve1
Authors: Mistry Jayalaxshmi , Berardi Andrea 
Published: August 2005

ABSTRACTFire is a natural ecological force in thecerrado. However, the increasing use of fire by people means that conservation areas are subject to frequent burns. The aim of this study was to assess the potential of fire in an ecological reserve in the Brazilian savannas (cerrado) of central Brazil. Data about vegetation type, topography, climate, and fuel characteristics were input into the fire prediction models BEHAVE and FARSITE to simulate fire behavior during different weather conditions and from different entry points into the conservation area. The results indicated that there is a higher probability of fire entry from particular border regions as a result of the fuel characteristics. The presence of invasive grasses, such asMelinis minutiflora, within parts of the reserve also significantly affected the pattern of fire spread. Wind speed greatly increased the spread and extent of fire. The study showed that significant improvements in modeling fire behavior in savannas still need to be made. This study was the initial stage in the development of a decision support system for fire management in thecerrado.
Wood Decomposition of Cyrilla racemiflora (Cyrillaceae) in Puerto Rican Dry and Wet Forests: A 13‐year Case Study1
Authors: Torres Juan A. , González Grizelle 
Published: August 2005

ABSTRACTWe studied the decomposition of Cyrilla racemiflora logs over a 13‐yr period in tropical dry and wet forests in Puerto Rico. The mean mass loss, ratio of soft to hard wood, nutrient concentrations, and the diversity of wood‐inhabiting organisms were greater in logs decomposing in the dry forest than in the wet forest. Termites were also more abundant in the logs collected from the tropical dry forest than the tropical wet forest. High moisture content and a low animal diversity on the logs in the wet forest seem to retard wood decay in this habitat. Wood decay rates in the tropical dry forest can be related to the high diversity of species and functional groups of wood‐inhabiting organisms.
Task Environment and Decentralization: A Cross-National Replication
Authors: Reimann Bernard C. 
Published: August 2005

A study of 19 Northeast Ohio manufacturing firms replicated the major result of a recent study of 30 industrial enterprises in India, in that management concern for task environmental agents was significantly related to the organizations' degree of decentralization. However, where this relationship had been linear in the Indian context, it was curvilinear in the shape of an inverted U in the U.S. setting. For relatively centralized firms a strong positive relationship between decentralization and management concern for task agents was observed, while this relationship actually was negative for the relatively decentralized firms. Some interesting differences between the Indian and American studies were also observed for relationships between decentralization and management concern for individual task agents (such as consumers, suppliers, or employees). In spite of some differences in the measure of both management concern and decentralization between the two studies, the replication of the Indian results in the very different industrial climate of the United States was considered as very encouraging. It suggested that management concern for task environmental agents could be a useful variable for crossnational organization research, since the relationship of this variable to decentralization was found to be similar to that observed in India, but at the same time somewhat more complex in keeping with the more complex industrial environment of the United States.
Interactive Effects of Uncertainty and Self-Control on the Acceptance of Responsibility for, and Satisfaction with, Performance
Authors: Dermer Jerry D. 
Published: August 2005

This study investigates the interactive effects of environmental uncertainty and self-control on the acceptance of responsibility for, and the satisfaction with, performance. A sample of graduate management students completed a questionnaire containing Rotter's locus of control scale and descriptions of four administrative situations, differing in environmental uncertainty and in the amount of self-control possible. Each case was followed by questions about the amount of responsibility they would accept if put in charge, and their satisfaction if they performed above or below average. An analysis of variance was then performed on these data. It was found that the situational factors identified significant differences and interactions but that the locus of control factor did not. Specifically, under both the low and high self-control situations, increasing the amount of environmental uncertainty reduced the amount of responsibility accepted. However, under the low self-control environment there was a significantly greater reduction both in the responsibility accepted and also expected of a subordinate. Similarly, under both levels of self-control, increasing environmental uncertainty lessened satisfaction with good performance and also lessened dissatisfaction with poor performance. However, again there was a significantly greater change under conditions of low self-control than for high self-control. Implications of the findings for the design of administrative systems are discussed.
Interdependence Among Organizational Variables
Authors: Knowles M. C. 
Published: August 2005

This study aimed to investigate the interrelationship between a set of organizational variables. It used a matrix analysis whereby fourteen work organizations or Sections within a company were assessed with respect to ten variables - production, quality, costs, job satisfaction of operatives, job satisfaction of supervisors, work anxiety, accidents, absence, labour turnover and industrial unrest. When the Sections were ranked on the individual measures it was found that wide and consistent differences existed between the Sections; within the Sections the variables were clearly interrelated. This effect could be called the interdependence phenomenon of organizational behaviour. This property was most pronounced in one group of Sections characterized by high performance achievements, favourable attitudes and organizational stability, and in another group of Sections characterized by low achievements, considerable dissatisfaction, and organizational instability involving high levels of accidents, absence, labour turnover or industrial unrest. The data illustrated how processes operating within the functional and dysfunctional work organizations tended to be self-reinforcing and the situations self-perpetuating. The psychological impact of being a member of the different work organizations was marked, and the more dysfunctional the work organization the more prevalent were the manifestations of withdrawal behaviour.
Evidence for ineffective erythropoiesis in severe sickle cell disease
Authors: Wu Catherine J. , Krishnamurti Lakshamanan , Kutok Jeffery L. , Biernacki Melinda , Rogers Shelby , Zhang Wandi , Antin Joseph H. , Ritz Jerome 
Published: August 2005

AbstractPeripheral destruction of sickled erythrocytes is a cardinal feature of sickle cell disease (SCD). Less well established is the potential contribution of ineffective erythropoiesis to the pathophysiology of this hemoglobinopathy. Since patients with SCD frequently develop mixed hematopoietic chimerism after allogeneic nonmyeloablative stem cell transplantation, we used this opportunity to directly compare the differentiation and survival of SCD and donor-derived erythropoiesis in vivo. Donor and recipient erythropoiesis was compared in 4 patients with SCD and 4 without SCD who developed stable mixed hematopoietic chimerism following transplant. Molecular analysis of chimerism in peripheral blood and bone marrow demonstrated higher expression of donor-derived β-globin RNA relative to the level of donor-derived genomic DNA in patients with SCD. Analysis of chimerism in immature (glycophorin A–positive [GYPA+], CD71hi) and mature (GYPA+, CD71neg) erythroblasts confirmed the intramedullary loss of SS erythroblasts with progressive maturation. In patients with SCD, relative enrichment of donor erythroid precursors began to appear at the onset of hemoglobinization. Ineffective erythropoiesis of homozygous hemoglobin S (SS) progenitors thus provides a maturation advantage for homozygous hemoglobin A (AA) or heterozygous hemoglobin S/hemoglobin A (SA) donor erythroid precursor cells that results in greater donor contribution to overall erythropoiesis following stem-cell transplantation and improvement of clinical disease.