bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of the tropical and subtropical Atlantic and Pacific Oceans on precipitation variability over Southern Central South America on seasonal time scales
Authors: Berri Guillermo J. , Bertossa Germán I.
Published: March 2004

This paper studies the temporal and spatial patterns of precipitation anomalies over southern central South America (SCSA; 22–40°S and 54–70°W), and their relationship with the sea‐surface temperature (SST) variability over the surrounding tropical and subtropical Atlantic and Pacific Oceans. The data include monthly precipitation from 68 weather stations in central–northern Argentina and neighbouring Brazil, Paraguay and Uruguay, and monthly SSTs from the NOAA dataset with a 2° resolution for the period 1961–93. We use the method of canonical correlation analysis (CCA) to study the simultaneous relationship between bi‐monthly precipitation and SST variability. Before applying the CCA procedure, standardized anomalies are calculated and a prefiltering is applied by means of an empirical orthogonal function (EOF) analysis. Thus, the CCA input consists of 10 EOF modes of SST and between 9 and 11 modes for precipitation and their corresponding principal components, which are the minimum number of modes necessary to explain at least 80% of the variance of the corresponding field. The results show that November–December presents the most robust association between the SST and SCSA precipitation variability, especially in northeastern Argentina and southern Brazil, followed by March–April and May–June. The period January–February, in contrast, displays a weak relationship with the oceans and represents a temporal minimum of oceanic influence during the summer semester. Based on the CCA maps, we identify the different oceanic and SCSA regions, the regional averages of SST and precipitation are calculated, and linear correlation analysis are conducted. The periods with greater association between the oceans and SCSA precipitation are November–December and May–June. During November–December, every selected region over SCSA reflects the influence of several oceanic regions, whereas during May–June only a few regions show a direct association with the oceans. The Pacific Ocean regions have a greater influence and are more widespread over SCSA; the Atlantic Ocean regions have an influence only over the northwestern and the southeastern parts of SCSA. In general, the relationship with the equatorial and tropical Atlantic and Pacific Oceans is of the type warm–wet/cold–dry, whereas the subtropical regions of both oceans show the opposite relationship, i.e. warm–dry/cold–wet. Copyright © 2004 Royal Meteorological Society
Comparison of Stratospheric Zonal Winds and El Niño–Southern Oscillation in Recent Decades
Authors: Kane R. P.
Published: March 2004

A comparison of the plots of the monthly and yearly values indicates that stratospheric winds and El Niño–southern oscillation (ENSO) parameters evolve differently and probably have no relationship with each other. The sharp commencement of the 1997–98 El Niño in February–March 1997 was not accompanied by any particular deviation from the general trend of the wind variation in those months. Spectral analysis for 1979 up to the present indicates that winds have only a quasi‐biennial oscillation (QBO) near 2.40 years as a prominent variation, whereas ENSO has main periodicities near 3.7 and 5.0 years and a small QBO near 2.50 years, slightly but significantly different from the wind QBO. Copyright © 2004 Royal Meteorological Society
Sea‐level pressure variability in the Po Plain (1765–2000) from homogenized daily secular records
Authors: Maugeri Maurizio , Brunetti Michele , Monti Fabio , Nanni Teresa
Published: March 2004

A homogenized 236 year daily regional sea‐level pressure (SLP) record is constructed for the Po Plain (north Italy) by means of six station records: Bologna, Genoa, Lugano, Milan, Padua and Turin. Station records are subjected to a first homogenization in order to reduce all observations to sea level and to 0°C and to correct the bias introduced by calculating daily means using different sets of observation hours. A second homogenization is performed by means of comparison with other Italian and European series. After homogenization, the root‐mean square error of the yearly station records is evaluated within 0.2 hPa after 1880, whereas for the periods 1834–1880 and 1765–1833 it is estimated as between 0.2 and 0.3 hPa and as around 0.4 hPa respectively. Trend analysis is applied to the annual and seasonal regional records and concerns both SLP and its day‐to‐day variability. The results show that neither the SLP nor its day‐to‐day variability have an evident trend when considering the entire 1765–2000 period. However, if the series is divided roughly in two parts, then significant trends can be highlighted. The annual and seasonal regional SLP records are also compared with corresponding regional temperature series. The results show that, especially in spring and in summer, temperature and SLP are in good agreement. Copyright © 2004 Royal Meteorological Society
An imprint and merge algorithm incorporating geometric tolerances for conformal meshing of misaligned assemblies
Authors: White David R. , Saigal Sunil , Owen Steven J.
Published: March 2004

A size tolerant algorithm for imprinting and merging adjacent part geometries is presented in this paper. This approach cleans up misaligned and dirty assembly geometry that is intended for conformal mesh generation. The algorithm first discretizes the boundary edges of adjacent faces into linear segments. The segments are then intersected and a partial intersection graph is calculated from the intersection results. The intersections are calculated by accounting for size tolerances to minimize the effect of misaligned parts on the meshing process. The partial intersection graph is next used to imprint the adjacent faces as appropriate. The imprints are generated using virtual geometry so that the tolerant topology created therein can be employed. Several examples are given to demonstrate the resulting improvement in the mesh quality of conformal meshes. The approach is shown to work robustly with misaligned and poorly defined parts. Copyright © 2004 John Wiley & Sons, Ltd.
Continuous approximation of material distribution for topology optimization
Authors: Matsui K. , Terada K.
Published: March 2004

In this paper, we propose a checkerboard‐free topology optimization method without introducing any additional constraint parameter. This aim is accomplished by the introduction of finite element approximation for continuous material distribution in a fixed design domain. That is, the continuous distribution of microstructures, or equivalently design variables, is realized in the whole design domain in the context of the homogenization design method (HDM), by the discretization with finite element interpolations. By virtue of this continuous FE approximation of design variables, discontinuous distribution like checkerboard patterns disappear without any filtering schemes. We call this proposed method the method of continuous approximation of material distribution (CAMD) to emphasize the continuity imposed on the ‘material field’. Two representative numerical examples are presented to demonstrate the capability and the efficiency of the proposed approach against some classes of numerical instabilities. Copyright © 2004 John Wiley & Sons, Ltd.
A meshless method with enriched weight functions for fatigue crack growth
Authors: Duflot Marc , Nguyen‐Dang Hung
Published: March 2004

The meshless method is particularly appropriate to solve crack propagation problems. In this paper, the fatigue growth of cracks in two‐dimensional bodies is considered. The analysis is based upon Paris' equation. New enriched weight functions are introduced in the meshless method formulation to capture the singularity at the crack tip. Simple problems show the accuracy and efficiency of this method. Then, it is applied to fatigue analysis of single‐ and multi‐cracked bodies under mixed‐mode conditions. Copyright © 2004 John Wiley & Sons, Ltd.
A systems framework for safety and security: The holistic paradigm
Authors: Hessami A. G.
Published: March 2004

New discoveries coupled with the incessant desire to improve performance and reduce cost of products and services tend to encourage the deployment of novel technologies, which are often more complex in nature than their earlier counterparts. However, recent experience bears witness to the need for better vision and foresight in appreciation of the detrimental aspects alongside seemingly beneficial and rewarding facets of modern systems, processes, and products. Among many aspects to the performance of systems, safety is a human‐focused and complex socio‐technical issue. The classical view of safety is largely biased towards the causality of hazardous states and failure of products, processes, and systems, often taking a narrow technical reliability perspective in place of sensitivity to human dimension. Later philosophies have advocated the extension of failure‐based approaches to take into account assessment of likely accidents and consequent harm to people. Against this setting, security, which is a major and more recent concern, is analogous to safety, differing mainly in malicious intent and deliberate causation rather than unplanned random or systematic causes. This paper proposes a new paradigm for holistic systems assurance, of which safety performance and security/vulnerability are key aspects. While principally focused on safety assurance, the proposed paradigm is broadly applicable to any facet of a system's performance and goes beyond the current horizons of systems safety landscape. It develops and proposes a more inclusive approach and extension of current systems safety domain, comprising scope and issues beyond accident causation and consequential loss. It further advocates a more extensive view of loss, encompassing harm to people and damage to the natural habitat as well as detriment to a business enterprise or society at large. References to safety assurance in this paper are synonymous with ensuring health, safety, and welfare of people. © 2004 Wiley Periodicals, Inc. Syst Eng 7: 99–112, 2004
A systems engineering framework for integrated automotive development
Authors: Loureiro Geilson , Leaney Paul G. , Hodgson Mike
Published: March 2004

Automotive development faces tightening regulatory requirements, shortening development cycle times, and growing complexity. To cope with such an environment, it is moving from a traditional evolutionary to a systems engineering approach. Great effort is being made for a shift from the traditional component focus, which has been enhanced by concurrent engineering, to a more broadened view supported by systems thinking. This broader view, however, is in practice strongly focused on the product elements of the system. This paper proposes a systems engineering framework for integrated automotive development—the total view approach. It is a modeling framework that integrates the product, its life cycle processes and their associated organizations throughout the requirements, functional and physical analysis processes, at all levels of the product breakdown structure, deriving attributes as emergent properties of a whole integrated system. The paper justifies the framework through a review of traditional and current automotive development and two case studies. A major benefit of the application of the framework is the ability to investigate early in the product development process the interactions between requirements and attributes not only of the product, but also of its life cycle processes and their associated organisations. This can lead to better product quality, lower life cycle cost, shorter development time, and manageable complexity. © 2004 Wiley Periodicals, Inc. Syst Eng 7: 153–166, 2004
Mavericks and free trade: Chile's pivotal role in the formation of the FTAA
Authors: Vachani Sushil
Published: March 2004

Bilateral and regional trade agreements are gaining importance as the World Trade Organization's
negotiations sputter. The future of regional integration agreements (RIAs) depends not only on large
countries such as the United States and Brazil, but also on small mavericks like Chile. This article examines
the generic roles played by different players in the game to form the Free Trade Area of the Americas
(FTAA), including Chile's pivotal role in helping the United States advance its objective of
creating the FTAA in the face of Brazilian resistance. Managers need to understand the effect of realignment of
trade arrangements on their sources of competitive advantage and adopt strategies to preempt their erosion.
Other small countries that exist in the shadows of large hegemons that dominate developing‐country RIAs
might benefit from lessons provided by Chile. © 2004 Wiley Periodicals, Inc.
A Novel Proton Transfer Self‐Associated Compound from Dipicolinic Acid and Guanidine and Its Cadmium(II) Complex: Synthesis, Characterization, Crystal Structure, and Solution Studies
Authors: Moghimi A. , Sheshmani Sh. , Shokrollahi A. , Aghabozorg H. , Shamsipur M. , Kickelbick G. , Aragoni M. Carla , Lippolis V.
Published: March 2004

A novel 1:2 proton transfer self‐associated compound LH2, (GH+)2(pydc2—), was synthesized from the reaction of dipicolinic acid, pydcH2, (2, 6‐pyridinedicarboxylic acid), and guanidine hydrochloride, (GH+)(Cl—). The characterization was performed using IR, 1H and 13C NMR spectroscopy and single‐crystal X‐ray diffraction. LH2 · H2O crystallizes in the space group C2/c of the monoclinic system and contains eight molecules per unit cell. The unit cell dimensions are: a = 26.480(5)Å, b = 8.055(2)Å, c = 14.068(3)Å. The first coordination complex (GH)2[Cd(pydc)2] · 2H2O, was prepared using LH2 and cadmium(II) iodide, and characterized by 1H and 13C NMR spectroscopy and X‐ray crystallography. The crystal system is triclinic with space group P1¯ with one molecule per unit cell. The unit cell dimensions are: a = 8.5125(7)Å, b = 11.0731(8)Å, c = 13.2404(10)Å. The cadmium(II) atom is six‐coordinated with a distorted octahedral geometry. The two pydc2— units are almost perpendicular to each other. The protonation constants of the building blocks of the pydc‐guanidine adduct, the equilibrium constants for the reaction of pydc2— with guanidine and the stoichiometry and stability of the Cd2+ complex with LH2 in aqueous solution were accomplished by potentiometric pH titration. The solution studies strongly support a self‐association between pydc2— and GH+ with a stoichiometry for the CdII complex similar to that observed for the isolated crystalline complex. In fact, the [Cd(pydc)2]2— complex was found as the most abundant species in solution (> 90 %) at a pH >5.
Modification of intracellular free calcium in cultured F2408 embryo fibroblasts by 3‐substituted‐2‐thiohydantoin derivatives
Authors: Incesu Z. , Benkli K. , Akalin G. , Kaplancikli Z.A.
Published: March 2004

3‐substituted‐2‐thiohydantoin derivatives were synthesized and their structures elucidated by IR, 1H‐NMR spectroscopy and elemental analysis. The cytotoxicity of the 2‐thiohydantoin derivatives to rat embryo fibroblasts (F2408) in vitro was determined, and the effects of these compounds on intracellular free Ca2+, [Ca2+]i, were measured by spectrofluorophotometry. Cytotoxicity was determined by metabolic reduction of a tetrazolium salt to a formazan dye (MTT assay). Compounds 4 and 7 showed cytotoxic activity, with IC50values in the range of 1–1.2 μM. Introduction of either chlorophenyl, metoxyphenyl, nitrophenyl or benzyl groups at C‐3 resulted in concentration‐dependent cytotoxic effects. Compounds 1–6 at 1 μM or more significantly increased [Ca2+]iin a dose‐dependent manner in the cultured fibroblasts. This action may have been mediated through intracellular calcium stores.
Involvement of protein kinases on the process of erythrophagocytis by Entamoeba histolytica
Authors: Batista Evander de J.O , De Souza Wanderley
Published: March 2004

Erythrophagocytic capacity of trophozoites of Entamoeba histolytica is considered a factor in the virulence of this pathogenic protozoan. We present evidence showing that such activity resembles the ingestion of microorganisms by highly differentiated phagocytic cells, such as macrophages. Previous treatment of the trophozoites with genistein or tyrphostin, inhibitors of tyrosine protein kinases, with staurosporine, a protein kinase C inhibitor, and wortmannin, a fungal metabolite that inhibits phosphoinositide 3‐OH kinase, significantly inhibited their erythrophagocytic capacity.
Shape transformation and cytoskeletal reorganization in activated non‐mammalian thrombocytes
Authors: Lee Kyeng‐Gea , Miller Todd , Anastassov Ivan , Cohen D. William
Published: March 2004

The nucleated thrombocytes of non‐mammalian vertebrates are partially flattened, ovoid cells morphologically distinct from mammalian platelets, and the extent of their functional equivalence is unknown. To test whether they resemble platelets in having similar F‐actin‐based post‐activation stages, rapid fixation/extraction/labeling methods were developed to reveal cytoskeletal organization in dogfish thrombocytes by confocal microscopy. Unactivated cells contained cortical F‐actin plus denser F‐actin co‐localizing with outer marginal band (MB) microtubules. In the post‐activation sequence, determined for the first time by continuous observation of individual thrombocytes following thrombin perfusion, cells rounded and blebbed, spread, and eventually flattened extensively. The MB twisted and then became disorganized, with microtubule bundles remaining centrally located and associated with nuclear clefts. In contrast, F‐actin occupied blebs and outward‐spreading cytoplasm, initially in spiky projections, then predominantly in stress fibers, and inhibitors of F‐actin assembly or myosin ATPase blocked shape changes. Thus, the post‐activation stages and cytoskeletal events observed in nucleated thrombocytes were found to parallel those of platelets.
Effects of ascorbic acid and ascorbic acid 2‐phosphate, a long‐acting vitamin C derivative, on the proliferation and differentiation of human osteoblast‐like cells
Authors: Takamizawa Shinji , Maehata Yojiro , Imai Katsuyuki , Senoo Haruki , Sato Sadao , Hata Ryu‐Ichiro
Published: March 2004

In order to investigate the effect of ascorbic acid (AsA) and ascorbic acid 2‐phosphate (Asc 2‐P), a long‐acting vitamin C derivative, on the growth and differentiation of human osteoblast‐like cells, we supplemented the culture medium of MG‐63 cells with various concentrations (0.25 to 1 mM) of these factors. Asc 2‐P significantly stimulated nascent cell growth at all concentrations in the presence of fetal bovine serum (FBS). On the other hand, AsA showed a growth repressive effect depending on its concentration, and that of FBS. Asc 2‐P also increased expression of osteoblast differentiation markers, such as collagen synthesis and alkaline phosphatase (ALP) activity. These stimulative activities of Asc 2‐P were attenuated by inhibitors of collagen synthesis, indicating that these effects were dependent on collagen synthesis. Electron micrographs of the cells showed the formation of a three‐dimensional tissue‐like structure endowed with a mature extracellular matrix in the presence of Asc 2‐P.
Quality of life in chronic pain is more associated with beliefs about pain, than with pain intensity
Authors: Lamé Inge E. , Peters Madelon L. , Vlaeyen Johan W.S. , Kleef Maarten V. , Patijn Jacob
Published: March 2004

Objectives. The objectives of this study were to investigate pain cognitions and quality of life of chronic pain patients referred to a multi‐disciplinary university pain management clinic and to search for predictors of quality of life.

Methods. A heterogeneous group of 1208 chronic pain patients referred to the Maastricht university hospital pain clinic participated in this cross‐sectional study. At the initial assessment, all patients completed a set of questionnaires on demographic variables, cause, location, pain intensity (McGill pain questionnaire, MPQ), pain coping and beliefs (pain coping and cognition list, PCCL), pain catastrophising (pain catastrophising scale, PCS) and eight dimensions of quality of life (Rand‐36).

Results. The results showed that the present sample of heterogeneous pain patients reported low quality of life on each domain and significantly lower scores than has been found in previous studies with other Dutch chronic pain populations. Patients with low back pain and multiple pain localisations experienced most functional limitations. Women reported more pain, more catastrophising thoughts about pain, more disability and lower vitality and general health. When tested in a multiple regression analysis, pain catastrophising turned out to be the single most important predictor of quality of life. Especially social functioning, vitality, mental health and general health are significantly associated with pain catastrophising.

Conclusions. Patients from a multi‐disciplinary university pain clinic experience strikingly low quality of life, whereby low back pain patients and patients with multiple pain localisations have the lowest quality of life. Pain catastrophising showed the strongest association with quality of life, and stronger than pain intensity.
Facilitation and inhibition of withdrawal reflexes following repetitive stimulation: electro‐ and psychophysiological evidence for activation of noxious inhibitory controls in humans
Authors: Bajaj Prem , Arendt‐Nielsen Lars , Andersen Ole K.
Published: March 2004

A systematic evaluation of nociceptive withdrawal reflexes and pain rating was undertaken in order to explore the mechanisms underlying temporal summation of repetitive electrocutaneous stimulation in healthy individuals (n=12; age=27.5 ± 1.5 years). Five‐second subreflex threshold (RT) electrocutaneous stimulation at different frequencies (single stimulus, 5, 10, and 20 Hz) and intensities (0.6RT and 0.8RT) was applied on the dorsum of the foot, and the withdrawal reflex from the ipsilateral biceps femoris muscle was measured. The subjects scored the pain intensity on a visual analogue scale (0–100 mm) for the beginning, the middle and the end phase of the 5 s series of stimulation, and the respective averaged reflex size was calculated. The reflex size increased at stimulus frequencies 10 Hz × 0.8RT and 20 Hz × 0.8RT as compared with 5 Hz × 0.8RT (SNK, P<0.05), and by an increase in current intensity from 0.6RT to 0.8RT (SNK, P<0.05). Pain intensity increased with the increase in the current intensity from 0.6RT to 0.8RT (SNK, P<0.05). Profound activation of inhibition following electrocutaneous pain stimuli was demonstrated by reduction in pain intensity and reflex size during the last second as compared with the first second at 0.6RT current intensity (SNK, P<0.05). The pain intensity peaked between 5 and 10 Hz (P<0.05) and was reduced at 20 Hz for current intensities at 0.8RT (P<0.05). This study provides evidence for both frequency dependent central integration of the repetitive electrocutaneous stimuli and activation of a pain inhibitory system by psychophysical and electrophysiological means, demonstrating the delicate balance between neuronal facilitation and inhibition in the human pain system.
Long term therapy of generalized anxiety disorder
Authors: Rouillon Frédéric
Published: March 2004

Generalized anxiety disorder (GAD) is a common (lifetime prevalence: 5.1%), recurrent condition, which often heralds other psychiatric disorders, notably depression. As by definition it is a disorder progressing over months, treatment should be designed on a long term basis. And yet, few studies have been conducted beyond the classical 6–8 weeks characterizing the acute treatment phase. This is especially true of anxiolytics, but also of antidepressants, with the exception of paroxetine and venlafaxine, which are the only drugs approved in this indication in Western countries. The efficacy of psychotherapy, notably relaxation and cognitive-behavioral therapy, is established in the treatment of GAD, but its preferred indications and possible combination with antidepressants are still to be specified. Long term, not to say very long term studies of GAD, as well as depression, will still be required in the future to improve its management and specify therapeutic modalities (combination treatment, optimal duration, continuous or intermittent therapy, choice of psychotherapeutic techniques or agents, …). Early and adequately prolonged treatment should not only result in more numerous remission periods, but also in decreased frequency of co-morbidities whether depressive, addictive, or of another nature, and should also reduce the social impact of GAD.
Patents as Surrogates for Inimitable and Non-Substitutable Resources
Authors: Markman Gideon D. , Espina Maritza I. , Phan Phillip H.
Published: March 2004

This study tests the view that competitive advantage lies in organizational processes and capabilities to secure patents. Since, by definition, patents are valuable and rare, here we test the extent to which patent citations and claims capture, respectively, inimitability and non-substitutability. Focusing on 85 publicly traded pharmaceutical firms (SIC 2834), we find that once the effects of firm size, past performance, and investment in innovation are held constant, inimitability is significantly related to firm profitability and new product introductions. Non-substitutability is significantly related to new product introductions only.
Chondrocyte apoptosis induced by hydrogen peroxide requires caspase activation but not mitochondrial pore transition
Authors: Lo Marvin Y. , Kim Hubert T.
Published: March 2004

The primary objective of this study was to test the hypothesis that inhibition of mitochondrial permeability transition and/or inhibition of caspase family enzymes can block chondrocyte apoptosis induced by H2O2. Primary human chondrocytes were isolated from normal cartilage by enzymatic digestion. Apoptosis was induced by exposure to H2O2. Chondrocyte apoptosis was quantified using an ELISA for nucleosome formation. Independent confirmation of apoptosis was obtained by TUNEL analysis. H2O2 induced apoptosis in primary human chondrocytes in a time and dose dependent manner. The effects of candidate apoptosis inhibitors were then tested. Chondrocytes were pre‐treated with inhibitors of mitochondrial permeability transition, or one of three different caspase inhibitors, and then incubated with H2O2. Apoptosis was then measured after 16 h of exposure to H2O2. Pre‐treatment with inhibitors of mitochondrial permeability transition did not block apoptosis induced by H2O2. A non‐selective caspase inhibitor, a caspase 3‐selective inhibitor, and a caspase 1‐selective inhibitor, all blocked chondrocyte apoptosis induced by H2O2. These results show that H2O2 triggers chondrocyte apoptosis through caspase activation, independent of mitochondrial membrane permeability transition. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Crosslinking density influences the morphology of chondrocytes photoencapsulated in PEG hydrogels during the application of compressive strain
Authors: Bryant Stephanie J. , Anseth Kristi S. , Lee David A. , Bader Dan L.
Published: March 2004

Chondrocyte deformation, which occurs during mechanical loading, is thought to play an important role in the mechano‐transduction pathway. In designing a scaffold that can be gelled in situ for cartilage tissue engineering, an important consideration is the influence of mechanical loading. This study tested the hypothesis that changes in the crosslinking density of a hydrogel scaffold influence the morphology of encapsulated chondrocytes in response to an applied load. Chondrocytes were entrapped in photo‐crosslinkable hydrogel scaffolds based on poly(ethylene glycol) (PEG) with two crosslinking densities, 0.119 and 0.376 mol/l, with the higher density having a 11‐fold higher compressive modulus. The cell‐embedded hydrogels were subjected to static compressive strains between 0% and 20% after 1 and 6 days of culture. Using confocal laser scanning microscopy, chondrocytes in the highly crosslinked gel at day 1 deformed more than gels in the more loosely crosslinked gel. By day 6, this finding was reversed. When single cells within a region were followed, heterogeneities in cell deformation were observed on both a macroscopic and microscopic scale. These heterogeneities were greater in the highly crosslinked gel. These findings demonstrate that different levels of cell deformation and heterogeneity may be obtained by varying the crosslinking density in PEG hydrogels. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Systematic single base‐pair substitution analysis of DNA binding by the cAMP receptor protein in cyanobacterium Synechocystis sp. PCC 6803
Authors: Omagari Katsumi , Yoshimura Hidehisa , Takano Mitsunori , Hao Dongyun , Ohmori Masayuki , Sarai Akinori , Suyama Akira
Published: March 2004

The cAMP receptor protein SYCRP1 in cyanobacterium Synechocystis sp. PCC 6803 is a regulatory protein that binds to the consensus DNA sequence (5′‐AAATGTGATCTAGATCACATTT‐3′) for the cAMP receptor protein CRP in Escherichia coli. Here we examined the effects of systematic single base‐pair substitutions at positions 4–8 (TGTGA) of the consensus sequence on the specific binding of SYCRP1. The consensus sequence exhibited the highest affinity, and the effects of base‐pair substitutions at positions 5 and 7 were the most deleterious. The result is similar to that previously reported for CRP, whereas there were differences between SYCRP1 and CRP in the rank order of affinity for each substitution.
In vivo non‐specific binding of λ CI and Cro repressors is significant
Authors: Bakk Audun , Metzler Ralf
Published: March 2004

We propose a thermodynamic model that includes the non‐specific binding of the λ phage regulatory proteins CI and Cro. By fitting the model to experimental in vivo data on activities of the two promoters P
RM and P
R versus concentration, we estimate the free energy upon non‐specific binding to be −4.1±0.9 kcal/mol for CI and −4.2±0.8 kcal/mol for Cro. For concentrations >100 nM of CI or Cro, we find that >50% of these proteins are non‐specifically bound. In particular, in a lysogen (∼250 CI monomeric equivalents per cell) nearly 90% of CI is non‐specifically bound.
Functional anatomy of hypnotic analgesia: A PET study of patients with fibromyalgia
Authors: Wik Gustav , Fischer Håkan , Bragée Björn , Finer Basil , Fredrikson Mats
Published: March 2004

Hypnosis is a powerful tool in pain therapy. Attempting to elucidate cerebral mechanisms behind hypnotic analgesia, we measured regional cerebral blood flow with positron emission tomography in patients with fibromyalgia, during hypnotically‐induced analgesia and resting wakefulness. The patients experienced less pain during hypnosis than at rest. The cerebral blood‐flow was bilaterally increased in the orbitofrontal and subcallosial cingulate cortices, the right thalamus, and the left inferior parietal cortex, and was decreased bilaterally in the cingulate cortex. The observed blood‐flow pattern supports notions of a multifactorial nature of hypnotic analgesia, with an interplay between cortical and subcortical brain dynamics.
An investigation of stress and pain perception during manual therapy in asymptomatic subjects
Authors: Vicenzino Bill , Cartwright Tim , Collins David , Wright Anthony
Published: March 2004

Stress perceived by the patient during the application of a manual therapy treatment technique may account for the reported findings of sympathoexcitation and hypoalgesia immediately after its application. This study investigated whether there was a difference in the level of perceived stress and pain before, during and after the application of a treatment condition (treatment, placebo or control technique), or whether the difference related to the time course of subject involvement in the study.

Twenty‐four asymptomatic subjects participated in a double‐blind, placebo‐controlled, within‐subjects study in which stress was measured with a stress rating scale and a stress visual analogue scale. Pain experienced by the subject during the application of the treatment technique was measured with a visual analogue scale and modified McGill pain questionnaire. There was no effect of the treatment condition on perceived stress, but there was a reduction in stress levels over the time course of involvement in the experiment, as demonstrated by pre‐application levels of stress. Pain was not produced by the treatment technique.

This study demonstrated that stress and pain were not features of the lateral glide manipulation of the cervical spine in asymptomatic subjects. If the dorsal periaqueductal grey region is responsible for the initial effects of manual therapy, as has been previously suggested, then stress and pain do not appear to play a role in activating this system during the application of a manual therapy treatment technique in asymptomatic subjects.
Elevated plasma levels of neuropeptide Y in female fibromyalgia patients
Authors: Anderberg Ulla Maria , Liu Zhurong , Berglund Lars , Nyberg Fred
Published: March 2004

Neuropeptide Y(NPY) co‐exists with norepinephrine in the sympathetic nervous system, and NPY may represent the sympathetic‐neuronal output. Fibromyalgia syndrome (FMS) patients have perturbations in the hypothalmic‐pituitary‐adrenal (HPA) axis and in the sympathetic stress axis as well. As opioid peptides, monoamines and sex steroids are integrated in the regulation of stress, it is interesting to further explore the role of NPY in FMS patients, as they show many symptoms that are related to perturbations of those systems.

In this study, plasma NPY levels were assessed in subgroups of FMS patients: cyclic (regular menstrual cycles), non‐cyclic (post‐menopausal), depressed and non‐depressed patients. In order to examine whether pain and other symptoms seen in FMS patients are correlated to the NPY levels, the patients were also registering 15 different symptoms daily during 28 days. Sex and age‐matched healthy controls were recruited for comparisons. Non‐parametric tests were used for the statistical analyses.

The results showed that the NPY levels were significantly elevated in the patients compared to the controls. In the luteal phase of the cyclic patients, the levels of the peptide were higher than in the corresponding controls. For the non‐cyclic patients, there was a positive correlation between physical symptoms and NPY levels, however, pain per se did not reach the significant level of correlation. The non‐depressed patients had the same levels of NPY as the depressed FMS patients, who also had a positive correlation between anxiety and NPY levels.

These results suggest that FMS patients have an altered activity in the NPY system, most likely due to prolonged and/or repeated stress, and that the hormonal state and time of the menstrual cycle also may be of importance in the complex pathophysiologic mechanism behind the development of FMS.
Quantification and immunocytochemical characteristics of trigeminal ganglion neurons projecting to the cornea: Effect of corneal wounding
Authors: De Felipe Carmen , Gonzalez Gertrudis G. , Gallar Juana , Belmonte Carlos
Published: March 2004

The number and immunocytochemical characteristics of trigeminal ganglion neurons providing sensory innervation to the cornea were studied in the mouse. Corneal neurons were retrogradely labelled with fluorogold placed on the cornea after removal of the epithelium with n‐heptanol. Corneal neurons were counted, sized and characterized immunocytochemically with antisera against substance P (SP), calcitonin gene‐related peptide (CGRP), calbindin, calretinin, and with a monoclonal antibody (RT97) against neurofilament proteins. A total of 258 corneal neurons were counted, most of them located in the ophthalmic division of the trigeminal ganglion. They represent only a small fraction (1.3%) of the population of trigeminal ganglion neurons. More than 70% of corneal neurons were classified as ‘small dark’ according to their cell body area and the absence of immunoreactivity to RT97. A low percentage of corneal neurons, usually large in size, contained calcium binding proteins. Fifty‐eight percent of the corneal neurons were immunoreactive to CGRP, and 20% to SP Corneal wounding with NaOH, which affects stromal nerve trunk, did not modify the total number of corneal neurons or their neuropeptide content. However, this increased the total number of calbindin‐positive and decreased the RT97‐positive neurons. Thus, unlike in other nociceptive neurons, peripheral axotomy did not modify the SP/CGRP content of corneal neurons.

Trigeminal ganglion neurons projecting to the cornea are similar in size and neuropeptide content to nociceptive neurons of other territories. Their number is high in relation to the corneal surface, thus confirming that the cornea has a large nociceptive representation in the trigeminal ganglion.
Pain and mechanical injury of human skin following needle insertions
Authors: Egekvist Henrik , Bjerring Peter , Arendt‐Nielsen Lars
Published: March 2004

Needle insertion is a very common invasive procedure, but little has been done to study how pain is related to the mechanical properties of the needle insertion, and how pain from the procedure may be minimized. The aim of the present study was to investigate the pain evoked by standardized needle insertion into the human skin. Needle insertions were performed with continuous registration of the mechanical force on the needle. Forty consecutive needle insertions to the depth of 8 mm with 27G and 30G needles, 2 and 19 mm/s velocities, and at 45 and 90 degree angles to the skin surface were performed in a randomized and blinded design in 30 healthy volunteers. The occurrence, intensity and quality of pain, as well as the maximum mechanical needle penetration force and the total mechanical workload were registered. The mechanical parameters of needle insertions were significantly related to needle size and velocity of insertion. Occurrence of pain and bleeding were significantly related to the needle size. High needle insertion velocity was significantly related to a higher rate of sharp and pricking pain, and low insertion velocity to a significantly higher rate of dull and burning pain. The present study provides quantitative data on pain and mechanical parameters of standardized needle insertions through normal human skin.
PET study on central processing of pain in trigeminal neuropathy
Authors: Hsieh Jen‐Chuen , Meyerson Björn A. , Ingvara Martin
Published: March 2004

Recent functional brain imaging studies with positron emission tomography (PET), in painful peripheral mononeuropathy and nitroglycerin‐provoked cluster headache attacks, suggest a preference of the right hemisphere, especially the anterior cingulate cortex (ACC) and the medial prefrontal cortex (MPFC), in attributing emotional valence and attention to the pain suffering. We have investigated the central processing of painful trigeminal neuropathy (PTN) in patients treated with electric extradural precentral gyrus stimulation (PCGS). Increased regional cerebral blood flow (rCBF) was detected in the right caudal ACC [Brodmann area (BA) 24] and anterior limbic thalamus, while a decreased activity was observed in the right MPFC (BA 9/32) during the habitual‐pain state, in comparison with the pain‐alleviated state regardless of the inflicted side of PTN. The involvement of BA 9/32 and the anterior limbic thalamus spatially extended to the left hemisphere, but the local maxima and a significant negative correlation between the rCBF changes in the two structures were found only in the right hemisphere. The activation of the caudal BA24 further supports the theory that ACC is crucial for the suffering in chronic pain. Our study not only verifies the preferential role of the right hemisphere in the appreciation of pain suffering, but further supports that sustained chronic pain, being devoid of the motivational component of an escape response, targets the right hemisphere, particularly the BA24 of the ACC.
Inferred causes of tree mortality in fragmented and intact Amazonian forests
Authors: D'Angelo Sammya A. , Andrade Ana C. S. , Laurance Susan G. , Laurance William F. , Mesquita Rita C. G.
Published: March 2004

In fragmented tropical landscapes, among the most pervasive causes of ecological change are edge effects – diverse ecological alterations associated with the abrupt, artificial boundaries of forest fragments (Laurance & Bierregaard 1997, Lovejoy et al. 1986, Turner 1996). A striking edge effect in fragmented Amazonian forests is chronically elevated tree mortality (Ferreira & Laurance 1997, Laurance et al. 1998a). Large (> 60 cm diameter) trees are especially vulnerable to fragmentation, dying three times faster within 300 m of edges than in forest interiors (Laurance et al. 2000). Elevated tree mortality alters canopy-gap dynamics, promotes a proliferation of disturbance-adapted successional species (Laurance et al. 1998b), reduces above-ground biomass (Laurance et al. 1997), and accelerates litter production (Didham & Lawton 1999, Sizer et al. 2000) and carbon cycling (Nascimento & Laurance, in press).
Defoliation of a monodominant rain-forest tree by a noctuid moth in Gabon
Authors: Maisels Fiona
Published: March 2004

Relatively little is known of the relationships between many lepidopteran species and their larval food plants in tropical rain forests, compared with temperate ecosystems. Species are often known only from the adult form, and the larvae and aspects of ecology, host plant, etc. are unknown (Williams 1971). Many species in the moth genus Achaea sometimes occur at high enough population densities to be defoliators, and several species are associated especially with forest trees: some are agricultural pests on groundnuts and castor oil plant (Ricinus communis) (Pinhey 1975, M. Shaw, pers. comm.). Achaea catocaloides occurs from West Africa through Uganda to East Africa (Seitz 1925) and has been recorded in interactions with ants in Cameroon (Dejean et al. 1991).
Seedling recruitment failure following dipterocarp mast fruiting
Authors: Blundell Arthur G. , Peart David R.
Published: March 2004

Many rain-forest trees in South-East Asia, including the dominant canopy family Dipterocarpaceae, reproduce in gregarious mast-fruiting events once every 2–11 y (Ashton et al. 1988). The dominant hypothesis for the evolution of masting is that predators are incapable of consuming mast seed crops, so that natural selection has favoured parent trees that fruit in synchrony (Janzen 1974, 1976). Mast flowering and fruiting are visually spectacular and quantified in harvest records for dipterocarp species producing large, oil-rich tengkawang seeds (Curran et al. 1999). Seedling recruitment following a mast is less obvious and has no immediate commercial value. However, a number of pulses of recruitment have been documented (Ashton et al. 1988, Chan 1980, Fox 1972, Liew & Wong 1973). These, together with general acceptance of the satiation hypothesis, have led to the widespread assumption that masts reliably increase seedling density and generate distinct seedling cohorts (Whitmore 1998). Indeed, foresters in Malaysia and Indonesia often recommend harvesting only after a mast, to ensure high densities of seedling regeneration.
Seasonal foraging ecology in a forest avifauna of northern Kenya
Authors: Borghesio Luca , Laiolo Paola
Published: March 2004

We studied the avian foraging ecology in a single montane forest of northern Kenya, analysing the pattern of seasonal variation (wet vs. dry period) and its relationship with habitat structure. The foraging behaviour of 28 species was described in terms of four major dimensions (i.e. foraging technique, food substrate, perching site and perching height). Seasonal rainfall produced an increase in vegetation growth in the lower vegetation layers, while fruiting and flowering peaked in the dry season. We did not find much seasonal variation in foraging ecology when we analysed our data at the species or at the community levels. At the guild level, however, we found some seasonal shifts in perching height, food substrate and foraging technique. Some of these shifts seemed to be determined by food availability and distribution, as omnivores increased fruit consumption when this resource was more abundant, and nectarivores tracked the vertical distribution of flowers. The vertical biomass distribution of this avian community seemed to be largely determined by food. However, seasonal variation in the total biomass of some guilds was probably related to factors not considered in this study, such as breeding, or intra-African migratory movements. Altogether, despite marked seasonal variation in vegetation structure and food resources, the bird assemblage showed little change in its feeding ecology and micro-habitat use. Hence, we suggest that changes in habitat structure and resource levels were coped with primarily by adjusting population density and food requirements through seasonal breeding or migration.
Ordinating tropical moth ensembles from an elevational gradient: a comparison of common methods
Authors: Brehm Gunnar , Fiedler Konrad
Published: March 2004

The analysis of beta diversity (inter-habitat diversity) of very species-rich and incompletely sampled tropical arthropod communities requires the choice of appropriate statistical tools. The performance of the three commonly employed ordination methods, correspondence analysis (CA), detrended correspondence analysis (DCA), and non-metric multidimensional scaling (NMDS), was compared on a large empirical data set of geometrid moths sampled along an altitudinal gradient in an Andean montane rain forest. Despite the high species richness and incompleteness of the ensembles, all methods depicted the same, readily interpretable patterns. Both CA and NMDS showed an arch-like structure, which hints at an underlying coenocline, whereas this arch was computationally eliminated in DCA. For this particular data set, CA and NMDS both provided convincing results while the detrending algorithm of DCA did not improve the interpretability of the data. Of the large number of similarity indices available to be used in combination with NMDS, the binary Sørensen and the abundance-based Normalized Expected Species Shared (NESS) index were tested. Performance of the indices was measured by comparing stress, a measure of poorness-of-fit in NMDS. NMDS ordinations with lowest values of stress were achieved by the NESS index with the parameter m set to its maximum (mmax). In contrast, ordinations based on NESS values with the parameter m set to 1 (identical with Morisita's index), had consistently higher stress values and performed worse than ordinations using Sørensen's index. Hence, if high values of m can be achieved in similar data sets, the NESS index with mmax is recommended for ordination purposes and Morisita's index should be avoided.
Effects of fire, food availability and vegetation on the distribution of the rodent Bolomys lasiurus in an Amazonian savanna
Authors: Layme Viviane Maria Guedes , Lima Albertina Pimentel , Magnusson William Ernest
Published: March 2004

We investigated the relative influences of vegetation cover, invertebrate biomass as an index of food availability and the short-term effects of fires on the spatial variation in densities of the rodent Bolomys lasiurus in an Amazonian savanna. Densities were evaluated in 31 plots of 4 ha distributed over an area of approximately 10×10 km. The cover of the tall grass (Trachypogon plumosus), short grass (Paspalum carinatum), shrubs and the extent of fire did not explain the variance in densities of Bolomys lasiurus. Food availability alone explained about 53% of the variance in B. lasiurus densities, and there was no significant relationship between insect abundance and vegetation structure. Fires had little short-term impact on the density of Bolomys lasiurus in the area we studied. As the species appears to respond principally to food availability, habitat suitability models based on easily recorded vegetation-structure variables, or the frequency of disturbance by fire, may not be effective in predicting the distribution of the species within savannas.