bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoinhibition in Mutants of Arabidopsis Deficient in Thylakoid Unsaturation
Authors: Vijayan Perumal , Browse John
Published: July 2002

Thylakoid lipid composition in higher plants is characterized by a high level of fatty acid unsaturation. We have screened four mutants of Arabidopsis that have reduced levels of fatty acid unsaturation. Three of the mutant lines tested, fad5,fad6, and the fad3-2 fad7-2 fad8 triple mutant, were more susceptible to photoinhibition than wild-type Arabidopsis, whereas one mutant, fab1, was indistinguishable from wild type. The fad3-2 fad7-2 fad8triple mutant, which contains no trienoic fatty acids in its thylakoid membranes, was most susceptible to photoinhibition. Detailed investigation of photoinhibition in the triple mutant revealed that the rate of photoinactivation of PSII was the same in wild-type and mutant plants. However, the recovery of photoinactivated PSII was slower infad3-2 fad7-2 fad8, relative to wild type, at all temperatures below 27°C. These results indicate that trienoic fatty acids of thylakoid membrane lipids are required for low-temperature recovery from photoinhibition in Arabidopsis.
Mutagenesis of the Glucose-1-Phosphate-Binding Site of Potato Tuber ADP-Glucose Pyrophosphorylase1
Authors: Fu Yingbin , Ballicora Miguel A. , Preiss Jack
Published: July 2002

Lysine (Lys)-195 in the homotetrameric ADP-glucose pyrophosphorylase (ADPGlc PPase) fromEscherichia coli was shown previously to be involved in the binding of the substrate glucose-1-phosphate (Glc-1-P). This residue is highly conserved in the ADPGlc PPase family. Site-directed mutagenesis was used to investigate the function of this conserved Lys residue in the large and small subunits of the heterotetrameric potato (Solanum tuberosum) tuber enzyme. The apparent affinity for Glc-1-P of the wild-type enzyme decreased 135- to 550-fold by changing Lys-198 of the small subunit to arginine, alanine, or glutamic acid, suggesting that both the charge and the size of this residue influence Glc-1-P binding. These mutations had little effect on the kinetic constants for the other substrates (ATP and Mg2+ or ADP-Glc and inorganic phosphate), activator (3-phosphoglycerate), inhibitor (inorganic phosphate), or on the thermal stability. Mutagenesis of the corresponding Lys (Lys-213) in the large subunit had no effect on the apparent affinity for Glc-1-P by substitution with arginine, alanine, or glutamic acid. A double mutant, SK198RLK213R, was also obtained that had a 100-fold reduction of the apparent affinity for Glc-1-P. The data indicate that Lys-198 in the small subunit is directly involved in the binding of Glc-1-P, whereas they appear to exclude a direct role of Lys-213 in the large subunit in the interaction with this substrate.
Interaction of Osmotic Stress, Temperature, and Abscisic Acid in the Regulation of Gene Expression in Arabidopsis
Authors: Xiong Liming , Ishitani Manabu , Zhu Jian-Kang
Published: July 2002

The impact of simultaneous environmental stresses on plants and how they respond to combined stresses compared with single stresses is largely unclear. By using a transgene (RD29A-LUC) consisting of the firefly luciferase coding sequence (LUC) driven by the stress-responsive RD29A promoter, we investigated the interactive effects of temperature, osmotic stress, and the phytohormone abscisic acid (ABA) in the regulation of gene expression in Arabidopsis seedlings. Results indicated that both positive and negative interactions exist among the studied stress factors in regulating gene expression. At a normal growth temperature (22°C), osmotic stress and ABA act synergistically to induce the transgene expression. Low temperature inhibits the response to osmotic stress or to combined treatment of osmotic stress and ABA, whereas low temperature and ABA treatments are additive in inducing transgene expression. Although high temperature alone does not activate the transgene, it significantly amplifies the effects of ABA and osmotic stress. The effect of multiple stresses in the regulation ofRD29A-LUC expression in signal transduction mutants was also studied. The results are discussed in the context of cold and osmotic stress signal transduction pathways.
Microsomal Electron Transfer in Higher Plants: Cloning and Heterologous Expression of NADH-Cytochromeb5Reductase from Arabidopsis
Authors: Fukuchi-Mizutani Masako , Mizutani Masaharu , Tanaka Yoshikazu , Kusumi Takaaki , Ohta Daisaku
Published: July 2002

AtCBR, a cDNA encoding NADH-cytochrome (Cyt)b5 reductase, and AtB5-A and AtB5-B, two cDNAs encoding Cyt b5, were isolated from Arabidopsis. The primary structure deduced from the AtCBR cDNA was 40% identical to those of the NADH-Cyt b5reductases of yeast and mammals. A recombinant AtCBR protein prepared using a baculovirus system exhibited typical spectral properties of NADH-Cyt b5 reductase and was used to study its electron-transfer activity. The recombinant NADH-Cytb5 reductase was functionally active and displayed strict specificity to NADH for the reduction of a recombinant Cyt b5 (AtB5-A), whereas no Cytb5 reduction was observed when NADPH was used as the electron donor. Conversely, a recombinant NADPH-Cyt P450 reductase of Arabidopsis was able to reduce Cytb5 with NADPH but not with NADH. To our knowledge, this is the first evidence in higher plants that both NADH-Cyt b5 reductase and NADPH-Cyt P450 reductase can reduce Cyt b5 and have clear specificities in terms of the electron donor, NADH or NADPH, respectively. This substrate specificity of the two reductases is discussed in relation to the NADH- and NADPH-dependent activities of microsomal fatty acid desaturases.
Winter Survival of Transgenic Alfalfa Overexpressing Superoxide Dismutase1
Authors: McKersie Bryan D. , Bowley Stephen R. , Jones Kim S.
Published: July 2002

To test the hypothesis that enhanced tolerance of oxidative stress would improve winter survival, two clones of alfalfa (Medicago sativa) were transformed with a Mn-superoxide dismutase (Mn-SOD) targeted to the mitochondria or to the chloroplast. Although Mn-SOD activity increased in most primary transgenic plants, both cytosolic and chloroplastic forms of Cu/Zn-SOD had lower activity in the chloroplast SOD transgenic plants than in the nontransgenic plants. In a field trial at Elora, Ontario, Canada, the survival and yield of 33 primary transgenic and control plants were compared. After one winter most transgenic plants had higher survival rates than control plants, with some at 100%. Similarly, some independent transgenic plants had twice the herbage yield of the control plants. Prescreening the transgenic plants for SOD activity, vigor, or freezing tolerance in the greenhouse was not effective in identifying individual transgenic plants with improved field performance. Freezing injury to leaf blades and fibrous roots, measured by electrolyte leakage from greenhouse-grown acclimated plants, indicated that the most tolerant were only 1°C more freezing-tolerant than alfalfa clone N4. There were no differences among transgenic and control plants for tetrazolium staining of field-grown plants at any freezing temperature. Therefore, although many of the transgenic plants had higher winter survival rates and herbage yield, there was no apparent difference in primary freezing injury, and therefore, the trait is not associated with a change in the primary site of freezing injury.
Isolation, Chromosomal Localization, and Differential Expression of Mitochondrial Manganese Superoxide Dismutase and Chloroplastic Copper/Zinc Superoxide Dismutase Genes in Wheat1
Authors: Wu Guohai , Wilen Ronald W. , Robertson Albert J. , Gusta Lawrence V.
Published: July 2002

Superoxide dismutase (SOD) gene expression was investigated to elucidate its role in drought and freezing tolerance in spring and winter wheat (Triticum aestivum). cDNAs encoding chloroplastic Cu/ZnSODs and mitochondrial MnSODs were isolated from wheat. MnSOD and Cu/ZnSOD genes were mapped to the long arms of the homologous group-2 and -7 chromosomes, respectively. Northern blots indicated that MnSOD genes were drought inducible and decreased after rehydration. In contrast, Cu/ZnSOD mRNA was not drought inducible but increased after rehydration. In both spring and winter wheat seedlings exposed to 2°C, MnSOD transcripts attained maximum levels between 7 and 49 d. Transcripts of Cu/ZnSOD mRNA were detected sooner in winter than in spring wheat; however, they disappeared after 21 d of acclimation. Transcripts of both classes of SOD genes increased during natural acclimation in both spring and winter types. Exposure of fully hardened plants to three nonlethal freeze-thaw cycles resulted in Cu/Zn mRNA accumulation; however, MnSOD mRNA levels declined in spring wheat but remained unchanged in winter wheat. The results of the dehydration and freeze-thaw-cycle experiments suggest that winter wheat has evolved a more effective stress-repair mechanism than spring wheat.
The Localization and Expression of the Class II Starch Synthases of Wheat1
Authors: Li Zhongyi , Chu Xiusheng , Mouille Gregory , Yan Liuling , Kosar-Hashemi Behjat , Hey Sandra , Napier Johnathan , Shewry Peter , Clarke Bryan , Appels Rudi , Morell Matthew K. , Rahman Sadequr
Published: July 2002

The starch granules of hexaploid wheat (Triticum aestivum) contain a group of three proteins known as SGP-1 (starch granule protein-1) proteins, which have apparent molecular masses of 100, 108, and 115 kD. The nature and role of these proteins has not been defined previously. We demonstrate that these polypeptides are starch synthases that are present in both the starch granule and the soluble fraction at the early stages of wheat endosperm development, but that are exclusively granule bound at mid and late endosperm development. A partial cDNA clone encoding a fragment of the 100-kD protein was obtained by screening a wheat endosperm cDNA expression library using monoclonal antibodies. Three classes of cDNA were subsequently isolated from a wheat endosperm cDNA library by nucleic acid hybridization and were shown to encode the 100-, 108-, and 115-kD proteins. The cDNA sequences are highly homologous to class II starch synthases and have the highest homology with the maize SSIIa (starch synthase IIa) gene. mRNA for the SGP-1 proteins was detected in the leaf, pre-anthesis florets, and endosperm of wheat and is highly expressed in the leaf and in the grain during the early to mid stages of development. We discuss the roles of the SGP-1 proteins in starch biosynthesis in wheat.
Coordinate Changes in Carbon Partitioning and Plastidial Metabolism during the Development of Oilseed Rape Embryos
Authors: Eastmond Peter J. , Rawsthorne Stephen
Published: July 2002

Measurements of metabolic fluxes in whole embryos and isolated plastids have revealed major changes in the pathways of carbon utilization during cotyledon filling by oilseed rape (Brassica napus L.) embryos. In the early cotyledon stage (stage A), embryos used sucrose (Suc) predominantly for starch synthesis. Plastids isolated from these embryos imported glucose-6-phosphate (Glc-6-P) and partitioned it to starch and fatty acids synthesis and to the oxidative pentose phosphate pathway in the ratio of 2:1:1 on a hexose basis. Of the substrates tested, Glc-6-P gave the highest rates of fatty acid synthesis by the plastids and pyruvate was used weakly. By the mid- to late-cotyledon stage (stage C), oil accumulation by the embryos was rapid, as was their utilization of Suc for oil synthesis in vitro. Plastids from C-stage embryos differed markedly from those of stage-A embryos: (a) pyruvate uptake and utilization for fatty acid synthesis increased by respectively 18- and 25-fold; (b) Glc-6-P partitioning was predominantly to the oxidative pentose phosphate pathway (respective ratios of 1:1:3); and (c) the rate of plastidial fatty acid synthesis more than doubled. This increased rate of fatty synthesis was dependent upon the increase in pyruvate uptake and was mediated through the induction of a saturable transporter activity.
Sensing of Osmotic Pressure Changes in Tomato Cells
Authors: Felix Georg , Regenass Martin , Boller Thomas
Published: July 2002

Cells of tomato (Lycopersicon esculentum) growing in suspension gradually depleted their culture medium and caused a steady decrease in its osmolality. When confronted with a sudden change in medium osmolality (a hypo-osmotic or hyperosmotic shock), respectively, these cells responded with volume changes and stress symptoms such as rapid extracellular alkalinization, efflux of K+-ions, and induction of 1-aminocyclopropane-1-carboxylate synthase acid, the key enzyme of ethylene biosynthesis. This array of stress symptoms is well known from cultured plant cells treated with microbial elicitors. Compared with elicitor treatment, induction of responses by hyperosmotic shock was slow and occurred only after increases of approximately 200,000 Pa in osmotic pressure. In contrast, hypo-osmotic shock induced responses without measurable lag and faster than elicitor treatments. Measurable medium alkalinization was induced when medium osmolality was reduced by as little as approximately 10 mosmol, a change corresponding to only approximately 0.2 bar in osmotic pressure. Like treatment with elicitors, hypo-osmotic shock induced specific changes in protein phosphorylations as demonstrated by in vivo labeling with [33P]orthophosphate. Exposure of cells to consecutive up- and down-shifts in medium osmolality showed that sensing of osmotic changes occurred within seconds, whereas adaptation to new osmotic conditions proceeded over hours. In conclusion, suspension-cultured plant cells display rapid, easily measurable macroscopic responses to osmotic shock and provide an interesting model system to study osmoregulation, a key process in plant growth and development.
Cell Division Activity during Apical Hook Development
Authors: Raz Vered , Koornneef Maarten
Published: July 2002

Growth during plant development is predominantly governed by the combined activities of cell division and cell elongation. The relative contribution of both activities controls the growth of a tissue. A fast change in growth is exhibited at the apical hypocotyl of etiolated seedlings where cells grow at different rates to form a hook-like structure, which is traditionally assumed to result from differential cell elongation. Using new tools we show asymmetric distribution of cell division during early stages of hook development. Cell divisions in the apical hook were predominantly found in subepidermal layers during an early step of hook development, but were absent in mutants exhibiting a hookless phenotype. In addition, during exaggeration of hook curvature, which is mediated by ethylene, a rapid change in the combined activities of cell division and cell elongation was detected. Our results indicate a fast change in cell division activity during apical hook development. We suggest that cell division together with cell elongation contributes to apical hook growth. Our results emphasize the change in the relative contribution of cell division and cell elongation in a fast growing structure like the apical hook.
A Patch-Clamp Study on the Physiology of Aluminum Toxicity and Aluminum Tolerance in Maize. Identification and Characterization of Al3+-Induced Anion Channels
Authors: Piñeros Miguel A. , Kochian Leon V.
Published: July 2002

The presence of Al3+ in the rhizosphere induces citrate efflux from the root apex of the Al-tolerant maize (Zea mays) hybrid South American 3, consequently chelating and reducing the activity of toxic Al3+ at the root surface. Because citrate is released from root apical cells as the deprotonated anion, we used the patch-clamp technique in protoplasts isolated from the terminal 5 mm of the root to study the plasma membrane ion transporters that could be involved in Al-tolerance and Al-toxicity responses. Acidification of the extracellular environment stimulated inward K+ currents while inhibiting outward K+currents. Addition of extracellular Al3+ inhibited the remaining K+ outward currents, blocked the K+inward current, and caused the activation of an inward Cl−current (anion efflux). Studies with excised membrane patches revealed the existence of Al-dependent anion channels, which were highly selective for anions over cations. Our success in activating this channel with extracellular Al3+ in membrane patches excised prior to any Al3+ exposure indicates that the machinery required for Al3+ activation of this channel, and consequently the whole root Al3+ response, is localized to the root-cell plasma membrane. This Al3+-activated anion channel may also be permeable to organic acids, thus mediating the Al-tolerance response (i.e. Al-induced organic acid exudation) observed in intact maize root apices.
N-Acetylglucosamine and Glucosamine-Containing Arabinogalactan Proteins Control Somatic Embryogenesis
Authors: van Hengel Arjon J. , Tadesse Zewdie , Immerzeel Peter , Schols Henk , van Kammen Ab , de Vries Sacco C.
Published: July 2002

In plants, complete embryos can develop not only from the zygote, but also from somatic cells in tissue culture. How somatic cells undergo the change in fate to become embryogenic is largely unknown. Proteins, secreted into the culture medium such as endochitinases and arabinogalactan proteins (AGPs) are required for somatic embryogenesis. Here we show that carrot (Daucus carota) AGPs can contain glucosamine andN-acetyl-d-glucosaminyl and are sensitive to endochitinase cleavage. To determine the relevance of this observation for embryogenesis, an assay was developed based on the enzymatic removal of the cell wall from cultured cells. The resulting protoplasts had a reduced capacity for somatic embryogenesis, which could be partially restored by adding endochitinases to the protoplasts. AGPs from culture medium or from immature seeds could fully restore or even increase embryogenesis. AGPs pretreated with chitinases were more active than untreated molecules and required an intact carbohydrate constituent for activity. AGPs were only capable of promoting embryogenesis from protoplasts in a short period preceding cell wall reformation. Apart from the increase in embryogenesis, AGPs can reinitiate cell division in a subpopulation of otherwise non-dividing protoplasts. These results show that chitinase-modified AGPs are extracellular matrix molecules able to control or maintain plant cell fate.
Azospirillum brasilense and Azospirillum lipoferum Hydrolyze Conjugates of GA20 and Metabolize the Resultant Aglycones to GA1 in Seedlings of Rice Dwarf Mutants
Authors: Cassán Fabricio , Bottini Rubén , Schneider Gernot , Piccoli Patricia
Published: July 2002

Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd andAzospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy anddx, when the inoculated seedlings were supplied with [17,17-2H2]GA20-glucosyl ester or [17,17- 2H2]GA20-glucosyl ether. Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17-2H2]GA20 and its subsequent 3β-hydroxylation to [17,17-2H2]GA1 by the microorganism for the dy mutant, and by both the rice plant and microorganism for the dx mutant.
The Arabidopsis Cell Plate-Associated Dynamin-Like Protein, ADL1Ap, Is Required for Multiple Stages of Plant Growth and Development
Authors: Kang Byung-Ho , Busse James S. , Dickey Carrie , Rancour David M. , Bednarek Sebastian Y.
Published: July 2002

Dynamin and dynamin-like proteins are GTP-binding proteins involved in vesicle trafficking. In soybean, a 68-kD dynamin-like protein called phragmoplastin has been shown to be associated with the cell plate in dividing cells (Gu and Verma, 1996). Five ADL1 genes encoding dynamin-like proteins related to phragmoplastin have been identified in the completed Arabidopsis genome. Here we report that ADL1Ap is associated with punctate subcellular structures and with the cell plate in dividing cells. To assess the function of ADL1Ap we utilized a reverse genetic approach to isolate three separate Arabidopsis mutant lines containing T-DNA insertions inADL1A. Homozygous adl1A seeds were shriveled and mutant seedlings arrested soon after germination, producing only two leaf primordia and severely stunted roots. Immunoblotting revealed that ADL1Ap expression was not detectable in the mutants. Despite the loss of ADL1Ap, the mutants did not display any defects in cytokinesis, and growth of the mutant seedlings could be rescued in tissue culture by the addition of sucrose. Although these sucrose-rescued plants displayed normal vegetative growth and flowered, they set very few seeds. Thus, ADL1Ap is critical for several stages of plant development, including embryogenesis, seedling development, and reproduction. We discuss the putative role of ADL1Ap in vesicular trafficking, cytokinesis, and other aspects of plant growth.
Buyer‐supplier relationships in the UK fresh produce industry
Authors: White Helen M.F.
Published: July 2002

Examines the dynamic changes that have occurred in the provision of fresh fruit and vegetables to the multiple retail sector in the UK over the last ten years. Supported by both conceptual development and empirical evidence, examines the nature, perceptions and evidence for managed portfolios of relationships that exist between a selection of suppliers and representatives from the major UK multiple retail chains. Recommendations are made to suppliers in managing their retail relationships for long‐term growth and security.
Changes in supermarket sales during and after a staged health promotion campaign
Authors: Närhinen Maria , Nissinen Aulikki , Puska Pekka
Published: July 2002

To test the feasibility of the use of supermarket sales data in evaluating a local point of purchase intervention and to assess the impact of the intervention six and 12 months later. Staged point of purchase intervention pilot study followed by a longitudinal observational study. The study was carried out in one supermarket in Mikkeli, Finland. Foods were classified as healthier or reference products based on their labelled content of salt and saturated fat. The sales of packaged foods containing reduced amounts of salt and/or saturated fat were promoted with a stepwise increasing intervention culminating in a “heart week”. In addition all unplanned promotional activities during the intervention were surveyed. Information on the sales of both the promoted products and reference products was collected daily from the supermarket’s computer system. Direct and proportional sales of both single products and whole food groups were analysed during the intervention and at follow‐up. In addition the supermarket environment and the supermarket’s advertising in the local newspaper were checked. Short‐term variations in the sales could be seen related to the promotion activities. During the heart week the sales of actively promoted healthier products increased by 37‐49 per cent. Variations in the sales of reference products could also be seen; the proportional sales of some healthier products declined significantly when the reference products were actively promoted. The supermarket environment was still affected by the intervention at both follow‐ups. The mean percentage salt content of the weekly sales had declined in all food groups and the mean percentage fat content had either declined or remained unchanged. Computerised sales data provide a useful and rapid means of evaluating supermarket based interventions. The intervention had an impact on the supermarket environment which was visible at follow‐up.
Making connections: innovation and collective learning in small businesses
Authors: Mitra Jay
Published: July 2002

Investigates the learning process in innovation and, in particular, the collective learning which underlines different types of innovation within the context of small‐ to medium‐sized enterprises (SMEs). Argues that innovation is often the result of interaction of various subjects, technologies, people and organisations, and that it is the learning that is derived from such interaction which underpins innovative activity. SMEs are better able to innovate when they are part of clusters because it is through the networking process and the management of externalities (key elements in clustering) that they develop new products, processes and services.
Mentoring in further and higher education: learning from the literature
Authors: Woodd Maureen
Published: July 2002

Concentrates on the mentoring support for teachers in further education (FE) and higher education (HE), rather than the mentoring of students following qualification programmes. Raises issues of definition and argues the need for peer mentoring. Evaluates mentoring models and explores issues of role modelling, selection, styles, skills and qualities. Covers literature from the USA, Canada, Australia and Europe and spans the period 1793‐1996, starting with a British Library reference called “The Female Mentor” and including the recent upsurge in mentoring interest across business and the professions.
Agile manufacturing
Authors: Parkinson Sharon
Published: July 2002

There have been a number of attempts to describe and promote more flexible approaches to manufacturing. This paper describes the principles underpinning a method known as agile manufacturing ‐‐ designed to be flexible and responsive and to bring together the engineering and marketing arms of the business to meet customer needs ‐‐ and discusses the kinds of technological support that are available to support the method.
Evolution of organizations in the new millennium
Authors: Harung Harald S. , Heaton Dennis P. , Alexander Charles N.
Published: July 2002

Progressive stages in the evolution of organizations correspond to progressively deeper aspects of the mind. The stage of task‐based management emphasized the more superficial sensorimotor and concrete thinking capacities; this approach of rigid rules and structures is now unsuited for an increasingly knowledge‐based economy. The next stage, process‐based management, makes greater use of the intellect of organizational members to design, implement, and evaluate systemic productivity improvements. A few organizations today demonstrate the lasting success of values‐based organizing, managing on the level of feelings and ego. The new millennium will see organizations that utilize the deepest level of human consciousness, connecting the human mind to the intelligence of natural law which spontaneously organizes for optimal simplicity, synergy, and holistic progress.
The search for reconciling insights: a “really useful” tool for managing paradox
Authors: Marsh Sheila , Macalpine Marion
Published: July 2002

This article uses stories from organisations to show how the “Helvig Square” can be an accessible and stimulating tool for managers learning to manage paradox. Many of us have been socialised and educated into binary, “either/or” thinking. As managers we find it hard to cope with current management dilemmas, such as how to plan and stay flexible, how to devolve decisions and keep corporate focus. In this article we build on the work of Pascale who uses the concept of paradox and working with “contending opposites”. This is important thinking, but we show how people can still be entrenched in opposing camps and unable to engage in meaningful dialogue. We explore how managers can expand their thinking through using the Helvig Square. This framework provides a tool which represents the problem more fully, offers a means of analysis and enables a focus on action.
Opinion paper: from interlending and document delivery to co‐operative collections and document access
Authors: Bjørnshauge Lars
Published: July 2002

By providing users with electronic fee‐paid access to co‐operatively‐developed digital collections, librarians can overcome some of their budgetary problems and can continue to have a role in meeting the information needs of research workers. If they continue to believe that interlending and document supply services should be free or subsidised then the quality of these ser bvices will continue to decline and dissatisfied users will gradually turn to commercial information providers to meet their needs.
Compressibility effects in modelling turbulent high speed mixing layers
Authors: Sellers Cheryl L. , Chandra Suresh
Published: July 2002

For high speed shear layers, variable density extensions of standard incompressible turbulence models have not proved to be adequate in explaining the experimentally observed reduction in growth rate with increase in the convective Mach number. Recently, Sarkar et al. suggested that, in addition to modelling the pressure dilatation, another dilatational correlation ‐ the compressible dissipation ‐ should be considered because of the enhanced dissipation known to be present in compressible turbulence. They have used the compressibility‐corrected model ‐ limited to the second power of the turbulent Mach number ‐ with the SPARK code for the computation of high speed shear layers and have obtained satisfactory agreement with some of the available experimental data. This simple algebraic compressibility model has been modified to include a fourth order turbulent Mach number term. Comparison of the predictions with results of several analytical models and experimental work shows good agreement.
Determination of the boundary temperature errors by variation of two temperature sensor locations in a one‐dimensional inverse heat conduction problem
Authors: Chen Tzu‐Fang , Lin Sui , Wang Joseph C.Y.
Published: July 2002

Investigates errors of the reconstruction temperatures at boundaries caused by variation of the locations of two temperature sensors in a one‐dimensional inverse heat conduction problem (IHCP) by using a time marching implicit finite difference inverse solver. Numerical simulation results of selected functions indicate that errors of the reconstruction temperature at each boundary can be presented by a simple relation. Each relation contains an unknown coefficient which can be determined by using one numerical simulation through the inverse solver of a pair specified sensor locations. This relation can then be used for estimating the other recovery errors at the boundary without using the inverse solver.
A case study of women academics’ views on equal opportunities, career prospects and work‐family conflicts in a British university
Authors: Forster Nick
Published: July 2002

This paper reports on the views that women academics have about their career prospects, equal opportunities and the conflicts they experience between their work and personal lives in one UK university. The university in question has formal equal opportunities policies and gender monitoring systems in place. However, very few women have progressed into senior academic roles. They continue to be handicapped by well‐ingrained structural and cultural barriers and by promotion systems that still largely rely on the publication records of candidates for appointments and promotions. But this is only half the story. Some of the women we interviewed reported that they had opted to put their careers on hold because of domestic and family responsibilities. A few have resigned themselves to never achieving senior positions because of these commitments. The wider implications of these findings are discussed, including the possible effects that this will have on recruiting women graduates into careers in higher education in the future.
Fire safety management at passenger terminals
Authors: Howarth Derek J. , Kara‐Zaitri Chakib
Published: July 2002

Discusses fire safety management in passenger terminals. Describes the design, development, implementation and validation of a fire safety management model for use in airports, railway and bus stations. The research carried out is based on a comprehensive analysis of 25 terminals (air, bus, rail and sea) in the UK and Europe. Develops the relationship existing between fire risk, people and fire safety management. Although the model is still being reviewed and augmented, it has already produced interesting results and has proved to be an efficient, robust and quantifiable tool for use by fire safety managers.
Constructing difficult‐to‐guess passwords
Authors: Cresson Wood Charles
Published: July 2002

Passwords have a convenience which other access controls do not. However, they must be made more effective through difficult‐to‐guess, easy‐to‐remember techniques, supported by policies and rules for their construction and expiration. Provides some guidelines for choosing passwords.
Determining responsibility for development of the moving assembly line
Authors: Heizer Jay H.
Published: July 2002

The development of the moving automobile final assembly line was a major milestone in manufacturing. The techniques required to make it work are demanding, but the resulting increase in productivity is phenomenal. Consequently, and not surprisingly, some people have claimed a major role in its development. The initial date for this innovation is either July 1908, or August 1913 and credit is given to Henry Ford, Charles Sorensen, Clarence Avery, or W.C. Klann, depending on whom one reads. This paper tries to clarify what happened on these dates and who was responsible. Investigation reveals that each of these men did play a role in development of the moving automobile assembly line.
Numerical analysis of stereolithography processes using the finite element method
Authors: Bugeda Gabriel , Cervera Miguel , Lombera Guillermo , Onate Eugenio
Published: July 2002

Stereolithography (SLA) is one of the most important techniques used in rapid prototyping processes. It has a great industrial interest because it allows for dramatic time savings with respect to traditional manufacturing processes. One of the main sources of error in the final dimensions of the prototype is the curl distortion effect owing to the shrinkage of the resin during the SLA process. Presents a study of the influence of different constructive and numerical parameters in the curl distortion, an analysis which was made using the computer code stereolithography analysis program, developed to model SLA processes using the finite element method. Also briefly presents this code.
Oligomerization of acidic fibroblast growth factor is not a prerequisite for its cell proliferation activity
Authors: Arunkumar Alphonse I. , Kumar Thallampuranam Krishnaswamy S. , Kathir Karuppanan Muthusamy , Srisailam Sampath , Wang Han‐Min , Leena Philominathan Sagaya Theresa , Chi Ya‐Hui , Chen Ho‐Chz , Wu Chieh‐Hsi , Wu Rong‐Tsun , Chang Gu‐Gang , Chiu Ing‐Ming , Yu Chin
Published: July 2002

Oligomerization of fibroblast growth factors (FGFs) induced on binding to heparin or heparan sulfate proteoglycan is considered to be crucial for receptor activation and initiation of biological responses. To gain insight into the mechanism of activation of the receptor by FGFs, in the present study we investigate the effect(s) of interaction of a heparin analog, sucrose octasulfate (SOS), on the structure, stability, and biological activities of a recombinant acidic FGF from Notophthalmus viridescens (nFGF‐1). SOS is found to bind to nFGF‐1 and significantly increase the thermodynamic stability of the protein. Using a variety of techniques such as size‐exclusion chromatography, sedimentation velocity, and multidimensional nuclear magnetic resonance (NMR) spectroscopy, it is shown that binding of SOS to nFGF‐1 retains the protein in its monomeric state. In its monomeric state (complexed to SOS), n‐FGF‐1 shows significant cell proliferation activity. 15N and 1H chemical shift perturbation and the intermolecular nuclear Overhauser effects (NOEs) between SOS and nFGF‐1 reveal that the ligand binds to the dense, positively charged cluster located in the groove enclosed by β‐strands 10 and 11. In addition, molecular modeling based on the NOEs observed for the SOS‐nFGF‐1 complex, indicates that SOS and heparin share a common binding site on the protein. In conclusion, the results of the present study clearly show that heparin‐induced oligomerization of nFGF‐1 is not mandatory for its cell proliferation activity.
LiveBench‐1: Continuous benchmarking of protein structure prediction servers
Authors: Bujnicki Janusz M. , Elofsson Arne , Fischer Daniel , Rychlewski Leszek
Published: July 2002

We present a novel, continuous approach aimed at the large‐scale assessment of the performance of available fold‐recognition servers. Six popular servers were investigated: PDB‐Blast, FFAS, T98‐lib, GenTHREADER, 3D‐PSSM, and INBGU. The assessment was conducted using as prediction targets a large number of selected protein structures released from October 1999 to April 2000. A target was selected if its sequence showed no significant similarity to any of the proteins previously available in the structural database. Overall, the servers were able to produce structurally similar models for one‐half of the targets, but significantly accurate sequence‐structure alignments were produced for only one‐third of the targets. We further classified the targets into two sets: easy and hard. We found that all servers were able to find the correct answer for the vast majority of the easy targets if a structurally similar fold was present in the server's fold libraries. However, among the hard targets—where standard methods such as PSI‐BLAST fail—the most sensitive fold‐recognition servers were able to produce similar models for only 40% of the cases, half of which had a significantly accurate sequence‐structure alignment. Among the hard targets, the presence of updated libraries appeared to be less critical for the ranking. An “ideally combined consensus” prediction, where the results of all servers are considered, would increase the percentage of correct assignments by 50%. Each server had a number of cases with a correct assignment, where the assignments of all the other servers were wrong. This emphasizes the benefits of considering more than one server in difficult prediction tasks. The LiveBench program (http://BioInfo.PL/LiveBench) is being continued, and all interested developers are cordially invited to join.
The application of frequency‐modulated continuous wave modulated thermoacoustic imaging in geological media
Authors: Liu Chang , Wang Chang , Mao Xu , Zhang Weite , Martínez‐López Raquel Isabel , Heredia‐Juesas Juan , Martinez‐Lorenzo Jose
Published: February 2025

A thermoacoustics imaging system is investigated in this paper to enhance conventional imaging modalities in geological subsurface situational awareness applications. While thermoacoustics imaging has traditionally been used in biological scenarios like breast cancer detection, this work aims to extend thermoacoustics imaging to geophysical applications by demonstrating that water‐saturated sand can be distinguished from dry and oil‐saturated sand based on their amplitude differences. This breakthrough enables the feasibility of monitoring water distribution in these media. Moreover, to compensate for the low conversion efficiency from electromagnetic power to thermoacoustics amplitude, the signal modulation method is used by applying the frequency‐modulated continuous wave techniques. The experiment results show that the frequency‐modulated continuous wave can enhance the signal‐to‐noise ratio while maintaining a similar resolution as the pulse‐excited thermoacoustics wave. These findings pave the way for the future use of thermoacousticsimaging in subsurface sensing and imaging of fluid flow and transport in porous media.
Thermodynamics Underpinning the Microbial Community‐Level Nitrogen Energy Metabolism
Authors: Seto Mayumi , Sasaki Risa , Ooka Hideshi , Nakamura Ryuhei
Published: February 2025

Nitrogen compounds often serve as crucial electron donors and acceptors in microbial energy metabolism, playing a key role in biogeochemical cycles. The energetic favorability of nitrogen oxidation–reduction (redox) reactions, driven by the thermodynamic properties of these compounds, may have shaped the evolution of microbial energy metabolism, though the extent of their influence remains unclear. This study quantitatively evaluated the similarity between energetically superior nitrogen reactions, identified from 988 theoretically plausible reactions, and the nitrogen community‐level network, reconstructed as a combination of enzymatic reactions representing intracellular to interspecies‐level reaction interactions. Our analysis revealed significant link overlap rates between these networks. Notably, composite enzymatic reactions aligned more closely with energetically superior reactions than individual enzymatic reactions. These findings suggest that selective pressure from the energetic favorability of redox reactions can operate primarily at the species or community level, underscoring the critical role of thermodynamics in shaping microbial metabolic networks and ecosystem functioning.
Voxel‐Based Dosimetry as a Means for Treatment Personalisation in Radioembolization: A Systematic Review
Authors: Schlegel R. N. , Griffin S. , Merchant A. , Ma D. , Owen A.
Published: February 2025

Introduction

Radionuclide therapy including 90Y radioembolization is an established form of brachytherapy for treatment of malignancy including hepatocellular carcinoma. Currently, there are several methods available to estimate patient absorbed dose, including voxel‐based dosimetry, that can achieve a level of personalisation in the planning and outcome assessments of radioembolization. Despite the advantages of voxel‐based dosimetry, it remains a relatively new concept in radioembolization. This study evaluates if voxel‐based dosimetry was associated with improved treatment efficacy in radioembolization planning.

Methods

A systematic review was conducted by searching relevant databases (Medline Ovid, PubMed, Embase Ovid, CINAHL Complete, Cochrane Library, CENTRAL, Australian New Zealand Clinical Trials Registry, ClinicalTrials.gov, WHO International Trials Registry, Google Scholar) for literature regarding voxel‐based dosimetry in radioembolization.

Results

A total of 41 papers were included for this systematic review. Review of these studies revealed that voxel‐based dosimetry can benefit numerous aspects of radioembolization in radionuclide therapy including predicting tumour response, toxicity and patient survival. Numerous studies also indicated that voxel‐based dosimetry in radioembolization is a more accurate approach in establishing a dose‐effect relationship in targeted radionuclide therapy when compared to other methods. Despite these promising findings, these studies did not investigate or comment on the accuracy of voxel‐based dosimetry.

Conclusion

The evidence from this review highlights that voxel‐based dosimetry can improve treatment efficacy in radioembolization planning. However, further studies are required to validate the accuracy and feasibility of voxel‐based dosimetry in clinical practice.
Influence of laser parameters on texturing of 3Y‐TZP and Ce‐TZP/Al2O3/SrAl12O19 composite
Authors: Fabris Douglas , Ränke Fabian , Fredel Márcio C. , Lasagni Andrés F. , Henriques Bruno
Published: February 2025

The development of new materials and surface functionalization processes has been extensively studied to further improve the performance of implants. This work explores the direct laser writing method as a potential alternative to produce controlled textures on the surface of traditional 3Y‐TZP and a novel high‐toughness composite (Ce‐TZP/Al2O3/SrAl12O19). A 532 nm picosecond laser source is used to produce lines in sintered samples of both materials with different values of laser fluence, repetition rate, and scanning speed. The resulting textured samples are analyzed using confocal and scanning electron microscopes. Both materials were successfully textured using the laser technique, but the groove morphology and geometry are highly dependent on the parameters used. While low energy results in shallow and irregular grooves, high energy can result in crack and resolidification layer. Overall, for the same set of parameters, the laser produced wider and deeper grooves in the nanocomposite (up to 30 µm wide and 26 µm deep) than in the 3Y‐TZP (up to 12 µm wide and 6 µm deep). Hence, this work showed the feasibility of laser texturing of traditional 3Y‐TZP and the novel Ce‐TZP/Al2O3/SrAl12O19 that can be further explored to functionalize their surfaces for biomedical applications.
An mHealth app technology to strengthen adverse event management of multi‐drug‐resistant tuberculosis in Vietnam: Protocol for a process evaluation of the V‐SMART trial
Authors: Nguyen Binh Hoa , Dang Tho T. H. , Hoang Duy Trinh , Do Thu Thuong , Van Dinh Luong , Nguyen Viet Nhung , Vu Dinh Hoa , Drabarek Dorothy , Nguyen Tram N. B. , Vu Dang , Nguyen Thu Anh , Marks Guy B. , Negin Joel , Fox Greg J. , Bernays Sarah , Yapa H. Manisha
Published: February 2025

Background

Drug‐related adverse events cause poorer treatment outcomes amongst people with multi‐drug‐resistant tuberculosis, exacerbating a major global public health problem. The Harnessing new mHealth technologies to Strengthen the Management of Multi‐Drug‐Resistant Tuberculosis in Vietnam (V‐SMART) trial tests whether a mobile health (mHealth) application (app) can optimise management of drug‐related adverse events, within routine health services in Vietnam. Implementation of digital health within routine services is complex and driven by behaviour change as well as a range of health system factors. Understanding implementation is key to informing the evidence base for digital health prior to scale up, despite its potential appeal.

Methods

Through a process evaluation of the V‐SMART trial, we aim to (i) understand the multi‐drug‐resistant tuberculosis service delivery context and how trial procedures are implemented within services; (ii) describe ‘dose’ and ‘reach’ of the app; and (iii) understand health worker and patient perspectives of app implementation and identify areas for improvement.

To achieve this, we will (i) conduct process maps (patient flow maps) to describe implementation of the mHealth intervention within routine multi‐drug‐resistant tuberculosis health services including adverse event management pathways at different levels of the health system; (ii) measure app usage by all participating health workers and people with multi‐drug‐resistant tuberculosis over time; and (iii) conduct a total of up to 45 semi‐structured interviews in seven provinces, with people with multi‐drug‐resistant tuberculosis, health workers, and policymakers, to identify determinants of app uptake and suggestions for future person‐centred app design. Interview topic guides are informed by the Theoretical Framework for Acceptability, Normalisation Process Theory, and the Tailored Implementation of Chronic Diseases framework respectively.

Discussion

The process evaluation will strongly complement the parent trial impact evaluation, and the economic evaluation. Moreover, it will inform future tailored approaches to scaling up digital health as part of broader health system strengthening initiatives.