bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Aging and Other Cardiovascular Risk Factors on Baroreflex Sensitivity
Authors: Piccirillo Gianfranco , Di Giuseppe Vincenza , Nocco Marialuce , Lionetti Marco , Moisè Antonio , Naso Camilla , Tallarico Demetrio , Marigliano Vincenzo , Cacciafesta Mauro 
Published: July 2002

OBJECTIVES: To examine the influence of known cardiovascular risk factors (cholesterol, blood glucose levels, arterial pressures, heart rate, and aging) on baroreflex sensitivity.DESIGN: An observational epidemiological study.SETTING: Geriatric Division at the Policlinico Umberto Primo, University of Rome La Sapienza.PARTICIPANTS: Two hundred three subjects whose ages ranged from 9 to 94 years, apparently healthy and free of detectable clinical evidence of atherosclerosis.MEASUREMENTS: All subjects underwent determination of baroreflex sensitivity by phenylephrine infusion (BSphe), and by a noninvasive method derived from spectral analysis of R‐R interval and arterial pressure variabilities (α index).RESULTS: The population, subdivided into tertiles for each variable studied, had lower BSphe values and lower α indexes as a function of age, plasma low‐density lipoprotein (LDL) cholesterol, and systolic blood pressure. The α index was significantly lower in both groups with elevated LDL cholesterol levels than in those with lower levels (II and III vs I tertile, P < .001), whereas BSphe differed significantly only in the two groups who had extreme levels of LDL (I vs III tertile, P < .001). Multiple regression analysis identified a negative association of the α index with age (P < .001), heart rate (P < .01), area under the glucose‐response curve (P < .001), and LDL cholesterol (P < .01), but of BSphe only with age (P < .001) and heart rate (P < .01).CONCLUSION: These findings indicate that some risk factors for coronary heart disease adversely influence baroreflex sensitivity.
Diluted magnetic semiconductors
Authors: Furdyna J. K. 
Published: July 2002

We review the physical properties of diluted magnetic semiconductors (DMS) of the type AII1−xMnxBVI (e.g., Cd1−xMnxSe, Hg1−xMnxTe). Crystallographic properties are discussed first, with emphasis on the common structural features which these materials have as a result of tetrahedral bonding. We then describe the band structure of the AII1−xMnxBVI alloys in the absence of an external magnetic field, stressing the close relationship of the sp electron bands in these materials to the band structure of the nonmagnetic AIIBVI ‘‘parent’’ semiconductors. In addition, the characteristics of the narrow (nearly localized) band arising from the half-filled Mn 3d5 shells are described, along with their profound effect on the optical properties of DMS. We then describe our present understanding of the magnetic properties of the AII1−xMnxBVI alloys. In particular, we discuss the mechanism of the Mn++-Mn++ exchange, which underlies the magnetism of these materials; we present an analytic formulation for the magnetic susceptibility of DMS in the paramagnetic range; we describe a somewhat empirical picture of the spin-glasslike freezing in the AII1−xMnxBVI alloys, and its relationship to the short range antiferromagnetic order revealed by neutron scattering; and we point out some not yet fully understood questions concerning spin dynamics in
DMS revealed by electron paramagnetic resonance. We then discuss the sp-d exchange interaction between the sp band electrons of the AII1−xMnxBVI alloy and the 3d5 electrons associated with the Mn atoms. Here we present a general formulation of the exchange problem, followed by the most representative examples of its physical consequences, such as the giant Faraday rotation, the magnetic-field-induced metal-to-insulator transition in DMS, and the properties of the bound magnetic polaron. Next, we give considerable attention to the extremely exciting physics of quantum wells and superlattices involving DMS. We begin by describing the properties of the two-dimensional gas existing at a DMS interface. We then briefly describe the current status of the AII1−xMnxBVI layers and superlattices (systems already successfully grown; methods of preparation; and basic nonmagnetic properties of the layered structures). We then describe new features observed in the magnetic behavior of the quasi-two-dimensional ultrathin DMS layers; and we discuss the exciting possibilities which the sp-d exchange interaction offers in the quantum-well situation. Finally, we list a number of topics which involve DMS but which have not been explicitly covered in this review such as elastic properties of DMS, DMS-based devices, and the emerging work on diluted magnetic semiconductors other than the AII1−xMnxBVI alloys—and we provide relevant literature references to these omitted topics.
A complete basis set model chemistry. V. Extensions to six or more heavy atoms
Authors: Ochterski Joseph W. , Petersson G. A. , Montgomery J. A. 
Published: July 2002

The major source of error in most ab initio calculations of molecular energies is the truncation of the one-electron basis set. Extrapolation to the complete basis set second-order (CBS2) limit using the N−1 asymptotic convergence of N-configuration pair natural orbital (PNO) expansions can be combined with the use of relatively small basis sets for the higher-order (i.e., MP3, MP4, and QCI) correlation energy to develop cost effective computational models. Following this strategy, three new computational models denoted CBS-4, CBS-q, and CBS-Q, are introduced. The mean absolute deviations (MAD) from experiment for the 125 energies of the G2 test set are 2.0, 1.7, and 1.0 kcal/mol, respectively. These results compare favorably with the MAD for the more costly G2(MP2), G2, and CBS-QCI/APNO models (1.6, 1.2, and 0.5 kcal/mol, respectively). The error distributions over the G2 test set are indistinguishable from Gaussian distribution functions for all six models, indicating that the rms errors can be interpreted in the same way that experimental uncertainties are used to assess reliability.
However, a broader range of examples reveals special difficulties presented by spin contamination, high molecular symmetry, and localization problems in molecules with multiple lone pairs on the same atom. These characteristics can occasionally result in errors several times the size expected from the Gaussian distributions. Each of the CBS models has a range of molecular size for which it is the most accurate computational model currently available. The largest calculations reported for these models include: The CBS-4 heat of formation of tetranitrohydrazine (91.5±5 kcal/mol), the CBS-4 and CBS-q isomerization energies for the conversion of azulene to naphthalene (ΔHcalc=−35.2±1.0 kcal/mol, ΔHexp=−35.3±2.2 kcal/mol), and the CBS-Q heat of formation of SF6 (ΔHcalc=−286.6±1.3 kcal/mol, ΔHexp=−288.3±0.2 kcal/mol). The CBS-Q value for the dissociation energy of a C–H bond in benzene (113.1±1.3 kcal/mol) is also in agreement with the most recent experimental result (112.0±0.6 kcal/mol). The CBS-QCI/APNO model is applicable to the prediction of the C–H bond dissociation energies for the primary (100.7±0.7 kcal/mol calc.) and secondary (97.7±0.7 kcal/mol calc., 97.1±0.4 kcal/mol exp.) hydrogens of propane.
Dialectical dialogue: the struggle for speech, repressive silence, and the shift to multiplicity
Authors: Gurevitch Zali 
Published: July 2002

ABSTRACTIn the present essay I intend to explore ‘dialectical dialogue’ in three distinct moments: the battle for recognition, the ethics of giving recognition, and the multiplicity of conversation. The essay begins with Hegel's figures of Master and Slave portraying the struggle of speech for recognition. This struggle culminates in a duel for mastery, which implies the repression and silencing of the other's speech. Ethical dialogue comes as a response to repressive silence, calling the other into egalitarian exchange. Ethical dialogue as such, however, remains within the dialectical framework of agonistic relations. To shift from dialectics to multiplicity, the essay turns from the politics of recognition to the poetics of conversation, to polyphony and to passage. I will follow the three moments both separately, through particular dialogic instances and theoretical perspectives, and as they develop, respond to, and shift from one to the other. Together they will portray an idea of the ‘social’ as a critical dialogic stance with its inherent dialectical betweenness and potential opening and expanding multiplicity.
Analysing patterns of religious participation in post‐communist Eastern Europe1
Authors: Need Ariana , Evans Geoffrey 
Published: July 2002

ABSTRACTIt is generally thought that processes of modernization generic to industrialized societies have resulted in a process of secularization with respect to conventional religious participation and observance in most Western countries. It is not at all clear, however, whether the post‐communist societies of Eastern Europe have followed this pattern. In this we paper we examine whether levels of religiosity in ten post‐communist societies – five generally Catholic in orientation and five Orthodox – are consistent with secularization theory, or whether instead they display, as some have suggested, the impact of seven decades of atheistic communism followed by a recent resurgence among the young. For this purpose we examine denominational membership and church attendance using descriptive and multivariate analysis of large‐scale national sample surveys conducted in the mid‐1990s. We find that age and educational differences in participation rates follow patterns expected on the basis of secularization theory with no evidence of resurgence among younger groups. Also, however, Catholic participation rates are significantly higher than Orthodox ones, indicating the importance of denomination in understanding patterns of religiosity in the post‐communist context.
Preventing and curtailing injecting drug use: a review of opportunities for developing and delivering ‘route transition interventions’
Authors: HUNT NEIL , GRIFFITHS PAUL , SOUTHWELL MATHEW , STILLWELL GARRY , STRANG JOHN 
Published: July 2002

AbstractInjecting is an important cause of viral and bacterial infection among drug users and is also associated with increased risk of overdose and severe dependence. Even when aggregate numbers of illicit drug users remain constant, significant health and social benefits may be achieved by a reduction in the prevalence and/or frequency of injecting. Yet, to date, little attention has been paid to reducing injecting (rather than drug use) as a policy objective. This paper reviews a range of ‘route transition interventions' (RTIs) that can be used to reduce injecting and its associated harms. Two points for intervention are distinguished: preventing injecting among existing non‐injecting drug users and promoting the transition away from injecting among current injectors. Targets for basic research and programme evaluation are discussed. In particular, it is argued that the time is now right for regional or national case studies that investigate how injecting can be reduced. [Hunt N, Griffiths P, Southwell M, Stillwell G, Strang J. Preventing and curtailing injecting drug use: a review of opportunities for developing and delivering route transition interventions’. Drug Alcohol Rev 1999;18:441–451]
Hepatitis B and C in alcohol‐dependent patients admitted to a UK alcohol inpatient treatment unit
Authors: Martínez‐Raga José , Marshall E. Jane , Keaney Francis , Best David , Ball David , Strang John 
Published: July 2002

AbstractThe prevalence of hepatitis B and C infection was studied in a sample of alcohol‐dependent patients admitted to a specialist alcohol inpatient unit to identify factors associated with hepatitis B and C infection. Laboratory, clinical and socio‐demographic data were collected from 277 admissions over a 3‐year period who were tested routinely for markers of hepatitis B and C infection. Of the 275 subjects tested for hepatitis C, 27 (9.8%) were positive to the hepatitis anti‐HCV IgG antibody. Of the 275 subjects tested for hepatitis B, 30 (10.9%) were positive to the hepatitis anti‐HBc IgG antibody. Few differences were found between hepatitis B positive and negative subjects. Hepatitis C positive individuals were more likely than Hepatitis C negative patients to have also been infected with the hepatitis B virus (p < 0.001), to have an unplanned discharge (p < 0.005) and to have ever used cannabis (p < 0.005), cocaine (p < 0.001), amphetamines (p < 0.001) or heroin (p < 0.001). They were also more likely to have a co‐morbid antisocial personality disorder (p < 0.001), a lifetime diagnosis of opiate dependence (p < 0.001) and cocaine dependence (p < 0.005), higher serum gamma glutamyl transferase (GGT) levels (p < 0.05) and a lower platelet count (p < 0.05). These findings may help clinicians to identify those alcohol dependent patients with risk factors for hepatitis virus infection.
Key Role of the Cdx2 Homeobox Gene in Extracellular Matrix–mediated Intestinal Cell Differentiation
Authors: Lorentz Olivier , Duluc Isabelle , Arcangelis Adèle De , Simon-Assmann Patricia , Kedinger Michèle , Freund Jean-Noël 
Published: July 2002

To explore the role of homeobox genes in the intestine, the human colon adenocarcinoma cell line Caco2-TC7 has been stably transfected with plasmids synthesizing Cdx1 and Cdx2 sense and antisense RNAs. Cdx1 overexpression or inhibition by antisense RNA does not markedly modify the cell differentiation markers analyzed in this study. In contrast, Cdx2 overexpression stimulates two typical markers of enterocytic differentiation: sucrase-isomaltase and lactase. Cells in which the endogenous expression of Cdx2 is reduced by antisense RNA attach poorly to the substratum. Conversely, Cdx2 overexpression modifies the expression of molecules involved in cell–cell and cell–substratum interactions and in transduction process: indeed, E-cadherin, integrin-β4 subunit, laminin-γ2 chain, hemidesmosomal protein, APC, and α-actinin are upregulated. Interestingly, most of these molecules are preferentially expressed in vivo in the differentiated villi enterocytes rather than in crypt cells. Cdx2 overexpression also results in the stimulation of HoxA-9 mRNA expression, an homeobox gene selectively expressed in the colon. In contrast, Cdx2-overexpressing cells display a decline of Cdx1 mRNA, which is mostly found in vivo in crypt cells. When implanted in nude mice, Cdx2-overexpressing cells produce larger tumors than control cells, and form glandular and villus-like structures.
Laminin-1 is known to stimulate intestinal cell differentiation in vitro. In the present study, we demonstrate that the differentiating effect of laminin-1 coatings on Caco2-TC7 cells is accompanied by an upregulation of Cdx2. To further document this observation, we analyzed a series of Caco2 clones in which the production of laminin-α1 chain is differentially inhibited by antisense RNA. We found a positive correlation between the level of Cdx2 expression, that of endogenous laminin-α1 chain mRNA and that of sucrase-isomaltase expression in these cell lines.
Taken together, these results suggest (a) that Cdx1 and Cdx2 homeobox genes play distinct roles in the intestinal epithelium, (b) that Cdx2 provokes pleiotropic effects triggering cells towards the phenotype of differentiated villus enterocytes, and (c) that Cdx2 expression is modulated by basement membrane components. Hence, we conclude that Cdx2 plays a key role in the extracellular matrix–mediated intestinal cell differentiation.
Detecting cryptically simple protein sequences using the SIMPLE algorithm
Authors: Albà M. Mar , Laskowski Roman A. , Hancock John M. 
Published: July 2002

Abstract
Motivation: Low-complexity or cryptically simple sequences are widespread in protein sequences but their evolution and function are poorly understood. To date methods for the detection of low complexity in proteins have been directed towards the filtering of such regions prior to sequence homology searches but not to the analysis of the regions per se. However, many of these regions are encoded by non-repetitive DNA sequences and may therefore result from selection acting on protein structure and/or function.
Results: We have developed a new tool, based on the SIMPLE algorithm, that facilitates the quantification of the amount of simple sequence in proteins and determines the type of short motifs that show clustering above a certain threshold. By modifying the sensitivity of the program simple sequence content can be studied at various levels, from highly organised tandem structures to complex combinations of repeats. We compare the relative amount of simplicity in different functional groups of yeast proteins and determine the level of clustering of the different amino acids in these proteins.
Availability: The program is available on request or online at http://www.biochem.ucl.ac.uk/bsm/SIMPLE
Contact: j.hancock@cs.rhul.ac.uk
* To whom correspondence should be addressed.
Rangelands, pastoralists and governments: interlinked systems of people and nature
Authors: Walker Brian H. , Janssen Marco A. 
Published: July 2002

We analyse commercially operated rangelands as coupled systems of people and nature. The biophysical components include: (i) the reduction and recovery of potential primary production, reflected as changes in grass production per unit of rainfall; (ii) changes in woody plants dependent on the grazing and fire regimes; and (iii) livestock and wool dynamics influenced by season, condition of the rangeland and numbers of wild and feral animals. The social components include the managers, who vary with regard to a range of cognitive abilities and lifestyle choices, and the regulators who vary in regard to policy goals.
We compare agent–based and optimization models of a rangeland system. The agent–based model leads to recognition that policies select for certain management practices by creating a template that governs the trajectories of the behaviour of individuals, learning, and overall system dynamics. Conservative regulations reduce short–term loss in production but also restrict learning. A free–market environment leads to severe degradation but the surviving pastoralists perform well under subsequent variable conditions. The challenge for policy makers is to balance the needs for learning and for preventing excessive degradation. A genetic algorithm model optimizing for net discounted income and based on a population of management solutions (stocking rate, how much to suppress fire, etc.) indicates that robust solutions lead to a loss of about 40% compared with solutions where the sequence of rainfall was known in advance: this is a similar figure to that obtained from the agent–based model.
We conclude that, on the basis of Levin's three criteria, rangelands with their livestock and human managers do constitute complex adaptive systems. If this is so, then command–and–control approaches to rangeland policy and management are bound to fail.
Binding specificity and the ligand dissociation process in the E. coli biotin holoenzyme synthetase
Authors: Kwon Keehwan , Streaker Emily D. , Beckett Dorothy 
Published: July 2002

AbstractThe binding of the Escherichia coli biotin holoenzyme synthetase to the two ligands, biotin and bio‐5′‐AMP, is coupled to disorder‐to‐order transitions in the protein. In the structure of the biotin complex, a “glycine‐rich” loop that is disordered in the apo‐enzyme is folded over the ligand. Mutations in three residues in this loop result in significant changes in the affinity of the enzyme for both biotin and bio‐5′‐AMP. The kinetic basis of these losses in the affinity resides primarily in changes in the unimolecular rates of dissociation of the complexes. In this work, isothermal titration calorimetry has been employed to examine the detailed thermodynamics of binding of three loop mutants to biotin and bio‐5′‐AMP. The energetic features of dissociation of the protein•ligand complexes also have been probed by measuring the temperature dependencies of the unimolecular dissociation rates. Analysis of the data using the Eyring formalism yielded entropic and enthalpic contributions to the energetic barrier to dissociation. The thermodynamic results coupled with the known structures of the apo‐enzyme and biotin complex have been used to formulate a model for progression from the ground‐state complex to the transition state in biotin dissociation. In this model, the transition‐state is characterized by both partial disruption of noncovalent bonds and acquisition of some of the disorder that characterizes the glycine‐rich loop in the absence of ligand.
A test of proposed rules for helix capping: Implications for protein design
Authors: Sagermann Martin , Mårtensson Lars‐Göran , Baase Walter A. , Matthews Brian W. 
Published: July 2002

Abstractα‐helices within proteins are often terminated (capped) by distinctive configurations of the polypeptide chain. Two common arrangements are the Schellman motif and the alternative αL motif. Rose and coworkers developed stereochemical rules to identify the locations of such motifs in proteins of unknown structure based only on their amino acid sequences. To check the effectiveness of these rules, they made specific predictions regarding the structural and thermodynamic consequences of certain mutations in T4 lysozyme. We have constructed these mutants and show here that they have neither the structure nor the stability that was predicted. The results show the complexity of the protein‐folding problem. Comparison of known protein structures may show that a characteristic sequence of amino acids (a sequence motif) corresponds to a conserved structural motif. In any particular protein, however, changes in other parts of the sequence may result in a different conformation. The structure is determined by sequence as a whole, not by parts considered in isolation.
Low levels of asparagine deamidation can have a dramatic effect on aggregation of amyloidogenic peptides: Implications for the study of amyloid formation
Authors: Nilsson Melanie R. , Driscoll Miles , Raleigh Daniel P. 
Published: July 2002

AbstractThe polypeptide hormone amylin forms amyloid deposits in Type 2 diabetes mellitus and a 10‐residue fragment of amylin (amylin20–29) is commonly used as a model system to study this process. Studies of amylin20–29 and several variant peptides revealed that low levels of deamidation can have a significant effect on the secondary structure and aggregation behavior of these molecules. Results obtained with a variant of amylin20–29, which has the primary sequence SNNFPAILSS, are highlighted. This peptide is particularly interesting from a technical standpoint. In the absence of impurities the peptide does not spontaneously aggregate and is not amyloidogenic. This peptide can spontaneously deamidate, and the presence of less than 5% of deamidation impurities leads to the formation of aggregates that have the hallmarks of amyloid. In addition, small amounts of deamidated material can induce amyloid formation by the purified peptide. These results have fundamental implications for the definition of an amyloidogenic sequence and for the standards of purity of peptides and proteins used for studies of amyloid formation.