bluuebunny/crossref_metadata_2025_split huggingface dataset:
TAK1‐mediated induction of nitric oxide synthase gene expression in glial cells
Authors: Bhat Narayan R. , Shen Qin , Fan Fan 
Published: September 2003

AbstractInflammatory cell signaling leading to transcriptional activation is primarily mediated by signal transduction via mitogen‐activated protein kinase (MAPK) and NFκB pathways. A common upstream kinase that signals the activation of these pathways is TGFβ–activated kinase 1 (TAK1), which itself becomes activated in response to cytokines and upon engagement of a class of cell surface receptors involved in innate immunity, that is Toll‐like receptors (TLRs) by bacterial and viral pathogens. This study directly tests the role of TAK1 in the induction of inducible nitric oxide (NO) synthase (iNOS) in glial cells, which represent immune‐regulatory cells of the CNS, by transient transfection assays. Transfection of C‐6 glia, primary astrocytes and a rat microglial cell line with TAK1 (but not its inactive form) along with its activator protein, TAK1‐binding protein 1 (TAB1) resulted in a marked stimulation of a co‐transfected rat iNOS promoter‐reporter construct (iNOS‐Luc). TAK1‐induced iNOS‐Luc activity was substantially inhibited by pharmacological inhibitors of the known downstream kinases, p38 MAPK and JNK (SB203580 and SP620125), and was almost completely blocked by co‐expression of a phosphorylation mutant of IκB. TAK1/TAB1 also induced the production of NO and the expression of iNOS in microglial cells in a p38 MAPK‐, JNK‐ and NFκB‐dependent manner. The results of these studies provide evidence for an important role for TAK1‐mediated intracellular signaling, via p38 MAPK, JNK and NFκB, in the transcriptional activation of iNOS in glial cells.
Is there a meaningful definition of sustainability?
Authors: Owens Susan 
Published: September 2003

AbstractAlthough the concept of ‘sustainable development’ has been hailed for its reconciliatory poten- tial, it has failed in practice to resolve enduring conflicts. Exploring the evolution of the concept—from its 19th-century antecedents through Brundtland to contemporary ‘Panglossian’ interpretations—the paper argues that difficulties of implementation are not transient but have deep roots. No conception of sustainable development can be adopted without making fundamental ethical and political choices, but the debate about such choices is nevertheless of great importance. It is argued that we should abandon our search for a singular, consensual definition of sustainability, but try as best we can to make progress in the absence of consensus.
Finite element modelling of contracting skeletal muscle
Authors: Oomens C. W. J. , Maenhout M. , van Oijen C. H. , Drost M. R. , Baaijens F. P. 
Published: September 2003

To describe the mechanical behaviour of biological tissues and transport processes in biological tissues, conservation laws such as conservation of mass, momentum and energy play a central role. Mathematically these are cast into the form of partial differential equations. Because of nonlinear material behaviour, inhomogeneous properties and usually a complex geometry, it is impossible to find closed-form analytical solutions for these sets of equations. The objective of the finite element method is to find approximate solutions for these problems.The concepts of the finite element method are explained on a finite element continuum model of skeletal muscle. In this case, the momentum equations have to be solved with an extra constraint, because the material behaves as nearly incompressible. The material behaviour consists of a highly nonlinear passive part and an active part. The latter is described with a two-state Huxley model. This means that an extra nonlinear partial differential equation has to be solved. The problems and solutions involved with this procedure are explained. The model is used to describe the mechanical behaviour of a tibialis anterior of a rat. The results have been compared with experimentally determined strains at the surface of the muscle. Qualitatively there is good agreement between measured and calculated strains, but the measured strains were higher.
Inverse and forward dynamics: models of multi–body systems
Authors: Otten E. 
Published: September 2003

Connected multi–body systems exhibit notoriously complex behaviour when driven by external and internal forces and torques. The problem of reconstructing the internal forces and/or torques from the movements and known external forces is called the ‘inverse dynamics problem’, whereas calculating motion from known internal forces and/or torques and resulting reaction forces is called the ‘forward dynamics problem’. When stepping forward to cross the street, people use muscle forces that generate angular accelerations of their body segments and, by virtue of reaction forces from the street, a forward acceleration of the centre of mass of their body. Inverse dynamics calculations applied to a set of motion data from such an event can teach us how temporal patterns of joint torques were responsible for the observed motion. In forward dynamics calculations we may attempt to create motion from such temporal patterns, which is extremely difficult, because of the complex mechanical linkage along the chains forming the multi–body system.
To understand, predict and sometimes control multi–body systems, we may want to have mathematical expressions for them. The Newton–Euler, Lagrangian and Featherstone approaches have their advantages and disadvantages. The simulation of collisions and the inclusion of muscle forces or other internal forces are discussed. Also, the possibility to perform a mixed inverse and forward dynamics calculation are dealt with. The use and limitations of these approaches form the conclusion.
Nitrogen Deficiency Increases Volicitin-Induced Volatile Emission, Jasmonic Acid Accumulation, and Ethylene Sensitivity in Maize
Authors: Schmelz Eric A. , Alborn Hans T. , Engelberth Juergen , Tumlinson James H. 
Published: September 2003

Abstract
Insect herbivore-induced plant volatile emission and the subsequent attraction of natural enemies is facilitated by fatty acid-amino acid conjugate (FAC) elicitors, such as volicitin [N-(17-hydroxylinolenoyl)-l-glutamine], present in caterpillar oral secretions. Insect-induced jasmonic acid (JA) and ethylene (E) are believed to mediate the magnitude of this variable response. In maize (Zea mays) seedlings, we examined the interaction of volicitin, JA, and E on the induction of volatile emission at different levels of nitrogen (N) availability that are known to influence E sensitivity. N availability and volicitin-induced sesquiterpene emission are inversely related as maximal responses were elicited in N-deficient plants. Plants with low N availability demonstrated similar volatile responses to volicitin (1 nmol plant-1) and JA (100 nmol plant-1). In contrast, plants with medium N availability released much lower amounts of volicitin-induced sesquiterpenes compared with JA, suggesting an alteration in volicitin-induced JA levels. As predicted, low N plants exhibited greater sustained increases in wound- and volicitin-induced JA levels compared with medium N plants. N availability also altered volicitin-E interactions. In low N plants, E synergized volicitin-induced sesquiterpene and indole emission 4- to 12-fold, with significant interactions first detected at 10 nL L-1 E. Medium N plants demonstrated greatly reduced volicitin-E interactions. Volicitin-induced sesquiterpene emission was increased by E and was decreased by pretreatment the E perception inhibitor 1-methylcyclopropene without alteration in volicitin-induced JA levels. N availability influences plant responses to insect-derived elicitors through changes in E sensitivity and E-independent JA kinetics.
Class I Chitinase and β-1,3-Glucanase Are Differentially Regulated by Wounding, Methyl Jasmonate, Ethylene, and Gibberellin in Tomato Seeds and Leaves
Authors: Wu Chun-Ta , Bradford Kent J. 
Published: September 2003

Abstract
Class I chitinase (Chi9) and β-1,3-glucanase (GluB) genes are expressed in the micropylar endosperm cap of tomato (Lycopersicon esculentum) seeds just before radicle emergence through this tissue to complete germination. In gibberellin (GA)-deficient mutant (gib-1) seeds, expression of Chi9 and GluB mRNA and protein is dependent upon GA. However, as expression occurs relatively late in the germination process, we investigated whether the genes are induced indirectly in response to tissue wounding associated with endosperm cap weakening and radicle protrusion. Wounding and methyl jasmonate (MeJA) induced Chi9 expression, whereas ethylene, abscisic acid, sodium salicylate, fusicoccin, or β-aminobutyric acid were without effect. Chi9 expression occurred only in the micropylar tissues when seeds were exposed to MeJA or were wounded at the chalazal end of the seed. Expression of Chi9, but not GluB, mRNA was reduced in germinating seeds of the jasmonate-deficient defenseless1 tomato mutant and could be restored by MeJA treatment. Chi9 expression during germination may be associated with “wounding” from cell wall hydrolysis and weakening in the endosperm cap leading to radicle protrusion, and jasmonate is involved in the signaling pathway for this response. Among these treatments and chemicals (other than GA), only MeJA and wounding induced a low level of GluB expression in gib-1 seeds. However, MeJA, wounding, and particularly ethylene induced both genes in leaves, whereas GA induced only Chi9 in leaves. Although normally expressed simultaneously during tomato seed germination, Chi9 and GluB genes are regulated distinctly and tissue specifically by hormones and wounding.
Negative Regulation of Abscisic Acid Signaling by theFagus sylvaticaFsPP2C1 Plays A Role in Seed Dormancy Regulation and Promotion of Seed Germination
Authors: González-García Mary Paz , Rodríguez Dolores , Nicolás Carlos , Rodríguez Pedro Luis , Nicolás Gregorio , Lorenzo Oscar 
Published: September 2003

AbstractFsPP2C1 was previously isolated from beech (Fagus sylvatica) seeds as a functional protein phosphatase type-2C (PP2C) with all the conserved features of these enzymes and high homology to ABI1, ABI2, and PP2CA, PP2Cs identified as negative regulators of ABA signaling. The expression of FsPP2C1 was induced upon abscisic acid (ABA) treatment and was also up-regulated during early weeks of stratification. Furthermore, this gene was specifically expressed in ABA-treated seeds and was hardly detectable in vegetative tissues. In this report, to provide genetic evidence on FsPP2C1 function in seed dormancy and germination, we used an overexpression approach in Arabidopsis because transgenic work is not feasible in beech. Constitutive expression of FsPP2C1 under the cauliflower mosaic virus 35S promoter confers ABA insensitivity in Arabidopsis seeds and, consequently, a reduced degree of seed dormancy. Additionally, transgenic 35S:FsPP2C1 plants are able to germinate under unfavorable conditions, as inhibitory concentrations of mannitol, NaCl, or paclobutrazol. In vegetative tissues, Arabidopsis FsPP2C1 transgenic plants show ABA-resistant early root growth and diminished induction of the ABA-response genes RAB18 and KIN2, but no effect on stomatal closure regulation. Seed and vegetative phenotypes of Arabidopsis 35S:FsPP2C1 plants suggest that FsPP2C1 negatively regulates ABA signaling. The ABA inducibility of FsPP2C1 expression, together with the transcript accumulation mainly in seeds, suggest that it could play an important role modulating ABA signaling in beechnuts through a negative feedback loop. Finally, we suggest that negative regulation of ABA signaling by FsPP2C1 is a factor contributing to promote the transition from seed dormancy to germination during early weeks of stratification.
Differential Regulation of Glucose-6-Phosphate Dehydrogenase Isoenzyme Activities in Potato
Authors: Hauschild Rüdiger , von Schaewen Antje 
Published: September 2003

Abstract
In plants, Glc-6-phosphate dehydrogenase (G6PDH) isoenzymes are present in the cytosol and in plastids. The plastidic enzymes (P1 and P2) are subject to redox regulation, but mechanisms that adjust cytosolic G6PDH activity are largely unknown. We adopted a leaf disc system for monitoring the effects of various conditions on G6PD isoform expression and enzyme activities in potato (Solanum tuberosum). Cytosolic G6PDH activity remained constant during water incubation in the dark. In continuous light or in the presence of metabolizable sugars in the dark, cytosolic G6PDH activity increased 6-fold within 24 h. Cycloheximide incubation demonstrated that enhanced cytosolic G6PDH activity depends on de novo protein synthesis. Osmotic change, phosphate sequestration, or oxidative stress did not affect cytosolic G6PDH activity. Furthermore, enzyme activity and protein contents closely followed the corresponding mRNA levels. Together with the fact that multiple SURE elements are present in the promoter region of the gene, these results suggest that cytosolic G6PDH activity is regulated by sugar availability at the transcriptional level. Plastidic G6PDH activity stayed constant during water incubation in the light and dropped to minimal levels within 6 h in the dark. Conversely, plastidic G6PDH activity of leaf discs incubated on Paraquat rose to 10-fold higher levels, which was not prevented by cycloheximide. Similar increases were found with nitrite, nitrate, or sulfate. No major changes in protein or mRNA contents of the plastidic P1 and P2 isoforms were registered. K m (Glc-6-phosphate) values of plastidic G6PDH activity differed between samples incubated on water or Paraquat, suggesting posttranslational modification of the plastidic enzyme(s). Immunoprecipitation of 32P-labeled samples with P1 isoform-specific antibodies showed that the chloroplast enzyme is subject to protein phosphorylation. Obviously, in extended dark periods, G6PDH activity in the stroma is restricted but can be stimulated in response to high demands for NADPH.
Properties of Fructan:Fructan 1-Fructosyltransferases from Chicory and Globe Thistle, Two Asteracean Plants Storing Greatly Different Types of Inulin
Authors: Vergauwen Rudy , Van Laere André , Van den Ende Wim 
Published: September 2003

Abstract
Remarkably, within the Asteraceae, a species-specific fructan pattern can be observed. Some species such as artichoke (Cynara scolymus) and globe thistle (Echinops ritro) store fructans with a considerably higher degree of polymerization than the one observed in chicory (Cichorium intybus) and Jerusalem artichoke (Helianthus tuberosus). Fructan:fructan 1-fructosyltransferase (1-FFT) is the enzyme responsible for chain elongation of inulin-type fructans. 1-FFTs were purified from chicory and globe thistle. A comparison revealed that chicory 1-FFT has a high affinity for sucrose (Suc), fructose (Fru), and 1-kestose as acceptor substrate. This makes redistribution of Fru moieties from large to small fructans very likely during the period of active fructan synthesis in the root when import and concentration of Suc can be expected to be high. In globe thistle, this problem is avoided by the very low affinity of 1-FFT for Suc, Fru, and 1-kestose and the higher affinity for inulin as acceptor substrate. Therefore, the 1-kestose formed by Suc:Suc 1-fructosyltransferase is preferentially used for elongation of inulin molecules, explaining why inulins with a much higher degree of polymerization accumulate in roots of globe thistle. Inulin patterns obtained in vitro from 1-kestose and the purified 1-FFTs from both species closely resemble the in vivo inulin patterns. Therefore, we conclude that the species-specific fructan pattern within the Asteraceae can be explained by the different characteristics of their respective 1-FFTs. Although 1-FFT and bacterial levansucrases clearly differ in their ability to use Suc as a donor substrate, a kinetic analysis suggests that 1-FFT also works via a ping-pong mechanism.
Preparing for the Pox: A Theory of Smallpox in Bengal and Britain
Authors: Naraindas Harish 
Published: September 2003

This essay is to be conceived in two parts. The first part is an exegesis of an eighteenth-century tract on the practice of smallpox inoculation in Bengal written by a Scottish medic. Cited repeatedly in the contemporary history and anthropology of smallpox in India, it has been invariably used to highlight the
technique
of inoculation in eighteenth-century India. Caught in disciplinary cleaving between anthropology and history, its original import has not been addressed. The exegesis in restoring the text to its intended import, argues that it offers a
theory
of smallpox, and in this theory the technique of inoculation is a moment in larger therapeutics. The latter-day privileging of this moment has resulted in seeing the nineteenth-century as a standoff between variolation (smallpox inoculation) and vaccination. The exegesis, however, recasts this as a passage from a therapeutics to a pure prophylactics that caccination represents. Having restored what I think is the central concern of the essay, I then begin to ask whether the essay is actually about the manner of inoculating for the smallpox in Bengal as Holwell says it is or is it actually about its practice in Britain. It is this very restoration, when we locate the essay in 18th century Britain, that allows us, in the latter part of the essay, to to see that not only is the theoretical articulation "induced" by his audience, but also every detail of the
description of the practice
, which has hitherto been seen as a description determined by his experience in India, is equally induced and
determined by his location in Britain
. While this could lead me to argue that Holwell's essay has nothing to do with India, I suggest that what the text effects, if not represents, is a kind of
translation
: one that is both possible and enabled by the fact that the kind of medical theory and practice that underlies disease and its cure is similar - not identical - in India and Britain.
Total ozone observations prior to the IGY. I: A history
Authors: Brönnimann S. , Staehelin J. , Farmer S. F. G. , Cain J. C. , Svendby T. , Svenøe T. 
Published: September 2003

AbstractCurrent data archives of total ozone measurements, with only few exceptions, provide data only since the International Geophysical Year (IGY, July 1957 to June 1958) when a global network was established. However, total ozone data from the period prior to the IGY could be useful to study the past variability of the stratosphere. For this purpose, we have systematically compiled information and data from approximately 60 total ozone measurement series prior to 1957. This paper provides an overview of the measurement principles and techniques, discusses the historical and scientific context of the observations and summarizes specific information for each series (location, time period of observation, instrument, responsible person, current state and availability of the data, references). In an accompanying paper the quality of 17 data series is critically assessed and some corrections are proposed. © Royal Meteorological Society, 2003. S. F. G. Farmer's contribution is Crown copyright
The impact of the cooling time‐scale on the subgrid moisture field during cloud formation through homogeneous cooling
Authors: Stiller Olaf 
Published: September 2003

AbstractCloud formation induced by homogeneous cooling has recently been found to substantially alter the moisture distribution. This study uses cloud‐resolving simulations of an idealized atmospheric layer to investigate the impact of the cooling time τ (i.e. of how fast the cooling is applied) on this process. The findings can be interpreted as an increased mixing (of air with different moisture content) for increasing τ. More specifically the mixing‐induced decrease of the moisture fluctuations and the corresponding decrease of the cloud water content are stronger for larger τ.This enhanced mixing is explained by the atmosphere's fast degrees of freedom (related to buoyancy oscillations) whose influence is found to grow for increasing τ. Exploiting scale separation between the different time‐scales, the behaviour of the fast degrees of freedom is deduced from the system's energy budget where the energy of the fast degrees of freedom is produced by the slow cooling process. © Crown copyright, 2003. Royal Meteorological Society
Shallow cumulus convection: A validation of large‐eddy simulation against aircraft and Landsat observations
Authors: Neggers R. A. J. , Duynkerke P. G. , Rodts S. M. A. 
Published: September 2003

AbstractLarge‐eddy simulation (LES) results of shallow cumulus convection are directly evaluated against in‐cloud aircraft measurements, as made during the Small Cumulus Microphysics Study (SCMS). To this purpose an LES case is first constructed, based on available observations (during SCMS). Then the simulations are directly compared with the in‐cloud measurements by using conditionally sampled fields. An advantage of the SCMS dataset is the combination of a range of different surface measurements, in‐cloud measurements by an aircraft at many levels in the cloud layer, and the availability of high‐resolution Landsat images.The results show that given the correct initial and boundary conditions the LES concept is capable of realistically predicting the bulk thermodynamic properties of temperature, moisture and liquid‐water content of the cumulus‐cloud ensemble as observed in SCMS. Furthermore, the vertical component of the in‐cloud turbulent kinetic energy and the cloud size distribution in LES were in agreement with the observations. These results support the credibility of cloud statistics as produced by LES in general, and encourage its use as a tool for testing hypotheses and developing parametrizations of shallow cumulus cloud processes.Several hypotheses which make use of conditionally sampled fields were tested on the SCMS data. The magnitudes and the decrease with height of the bulk entrainment rate following from the SCMS data confirm the typical values of the order of magnitude of 10−3 m−1 as reported in several other recent LES studies. An alternative formulation of the lateral entrainment rate as a function of the liquid‐water content and the mean lapse rate agrees well with the original form based on the conserved variables. Applying an often‐used simplified equation for the cloud vertical velocity to the aircraft measurements results in a reasonably closed budget. Copyright © 2003 Royal Meteorological Society