bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular dissection of PI3Kβ synergistic activation by receptor tyrosine kinases, GβGγ, and Rho-family GTPases
Authors: Duewell Benjamin R. , Wilson Naomi E. , Bailey Gabriela M. , Peabody Sarah E. , Hansen Scott D.
Published: January 2024

The class 1A phosphoinositide 3-kinase (PI3K) beta (PI3Kβ) is functionally unique in the ability to integrate signals derived from receptor tyrosine kinases (RTKs), heterotrimeric guanine nucleotide-binding protein (G-protein)-coupled receptors (GPCRs), and Rho-family GTPases. The mechanism by which PI3Kβ prioritizes interactions with various membrane tethered signaling inputs, however, remains unclear. Previous experiments have not been able to elucidate whether interactions with membrane-tethered proteins primarily control PI3Kβ localization versus directly modulate lipid kinase activity. To address this gap in our understanding of PI3Kβ regulation, we established an assay to directly visualize and decipher how three distinct protein interactions regulate PI3Kβ when presented to the kinase in a biologically relevant configuration on supported lipid bilayers. Using single molecule Total Internal Reflection Fluorescence (TIRF) Microscopy, we determined the mechanism controlling membrane localization of PI3Kβ, prioritization of signaling inputs, and lipid kinase activation. We find that auto-inhibited PI3Kβ prioritizes interactions with RTK-derived tyrosine phosphorylated (pY) peptides before engaging either GβGγ or Rac1(GTP). Although pY peptides strongly localize PI3Kβ to membranes, stimulation of lipid kinase activity is modest. In the presence of either pY/GβGγ or pY/Rac1(GTP), PI3Kβ activity is dramatically enhanced beyond what can be explained by simply increasing the strength of membrane localization. Instead, PI3Kβ is synergistically activated by pY/GβGγ and pY/Rac1(GTP) through a mechanism consistent with allosteric regulation.
Spatial-temporal order-disorder transition in angiogenic NOTCH signaling controls cell fate specification
Authors: Kang Tae-Yun , Bocci Federico , Nie Qing , Onuchic José Nelson , Levchenko Andre
Published: January 2024

Angiogenesis is a morphogenic process resulting in the formation of new blood vessels from pre-existing ones, usually in hypoxic micro-environments. The initial steps of angiogenesis depend on robust differentiation of oligopotent endothelial cells into the Tip and Stalk phenotypic cell fates, controlled by NOTCH-dependent cell-cell communication. The dynamics of spatial patterning of this cell fate specification are only partially understood. Here, by combining a controlled experimental angiogenesis model with mathematical and computational analyses, we find that the regular spatial Tip-Stalk cell patterning can undergo an order-disorder transition at a relatively high input level of a pro-angiogenic factor VEGF. The resulting differentiation is robust but temporally unstable for most cells, with only a subset of presumptive Tip cells leading sprout extensions. We further find that sprouts form in a manner maximizing their mutual distance, consistent with a Turing-like model that may depend on local enrichment and depletion of fibronectin. Together, our data suggest that NOTCH signaling mediates a robust way of cell differentiation enabling but not instructing subsequent steps in angiogenic morphogenesis, which may require additional cues and self-organization mechanisms. This analysis can assist in further understanding of cell plasticity underlying angiogenesis and other complex morphogenic processes.We investigate the spatial and temporal patterns of Tip/Stalk specification and the ensuing angiogenic sprouting by using a novel controlled micro-engineered experimental model of angiogenesis and a set of mathematical models of the spatially resolved, cell population-level VEGF-NOTCH signaling. Our analysis provides a dynamic view of the initial step of angiogenesis, revealing fluctuations in its onset, and features suggesting transitions between order and disorder in cell organization. These findings suggest how a potentially very restrictive patterning mechanism can become sensitive to a variety of environmental cues. This sensitivity can be crucial for proper vascularization of a damaged organ, and may suggest new ways of analyzing angiogenesis in the context of cancer and other pathologies. This analysis also suggests a framework for understanding of other instances of NOTCH-mediated patterning processes.
Kunnskapsoppsummering og klassifisering av tiltaket: Flyt
Authors: Sagatun Åse , Grøm Sæle Rannveig
Published: January 2024

Bakgrunn: Flyt er et livsmestringsprogram for elever på 10. trinn som har til hensikt å gjøre deltakere bedre rustet til å gjennomføre videregående skole. Programmet er et styrkebasert gruppetiltak for ungdom i risiko for å droppe ut fra videregående, men ungdom uten kjent risiko inkluderes også. For elever omfatter tiltaket totalt 80 timer med organiserte aktiviteter fordelt på helg- og kveldssamlinger gjennom ca. 15 måneder, med oppstart i begynnelsen av 10 klasse. Foreldre deltar på fire samlinger. Kronprinsparets Fond er tiltaksutviklere, eiere av tiltaket og står for opplæring av veiledere i programmet. Tiltaket gjennomføres lokalt i kommunen. Det første kullet til å prøve programmet gjennomførte i 2019, og i 2022-23 gjennomføres det i 17 kommuner.
Metode: Denne kunnskapsoppsummeringen bygger på et systematisk litteratursøk i databasene Embase, Medline og Psykinfo, NORART, Cochrane, Cristin, NORA, SCOPUS og SweMed. Det er også søkt i internasjonale kunnskapsdatabaser om evidens samt innhentet informasjon om tiltaket fra tiltakseier. Litteratursøk og annen innhentet informasjon ble gjennomgått for å identifisere nordiske effektstudier, internasjonale oppsummeringsstudier og eventuelt andre norske studier om tiltaket.
Resultater: Resultatene består av en vurdering av tiltakets beskrivelse, foreliggende effektstudier, forskningsmetodisk kvalitet og implementeringskvalitet. Flyt er godt beskrevet og bygger på et kjent teorigrunnlag. Det er gjennomført to norske evalueringer som har kartlagt brukererfaringer ved intervju, samt endring på noen variabler målt ved spørreskjema. Det foreligger ingen nordiske effektstudier av tiltaket.
Konklusjon: Flyt har en god teoretisk forankring og detaljerte beskrivelser av innhold og prosedyrer. Vi anbefaler å gjennomføre effektstudier som adresserer målsetningene eksplisitt med et tilstrekkelig stringent design. Flyt klassifiseres på evidensnivå 2 – Teoretisk begrunnede tiltak.
FACILITADORES Y BARRERAS PARA LA IMPLEMENTACIÓN DE UN PROGRAMA DE ENFERMERÍA DE PRÁCTICA AVANZADA EN CHILE
Authors: Márquez-Doren Francisca , Lucchini-Raies Camila , González-Agüero Marcela , Varela-Loreto Camila , Palma-Rivadeneira Silvia
Published: January 2024

INTRODUCCIÓN: El desarrollo de la Enfermería de Práctica Avanzada se ha transformado en una tendencia global en las últimas décadas. Desde que esta formación de posgrado emergió en Estados Unidos ha trascendido a otros continentes y países. Si bien en la región de las Américas estos programas aún tienen un carácter incipiente, la Organización Panamericana de la Salud ha realizado esfuerzos constantes para relevar su aporte al logro del acceso universal de salud y al fortalecimiento de la atención primaria de salud y a la fuerza laboral de Enfermería. OBJETIVO: Este artículo presenta una reflexión acerca de la implementación de un programa de Práctica Avanzada en Chile, analizando facilitadores y desafíos del proceso. DESARROLLO: En respuesta a las necesidades del país y al contexto, la Escuela de Enfermería UC abrió su primer programa en 2021, específicamente en el área de la oncología, enfocado a abordar las brechas de acceso y cobertura en el área. Se plantean facilitadores y desafíos de la implementación que coinciden con lo que ocurre a nivel internacional CONCLUSIONES: Las fortalezas como los desafíos identificados proporciona una clara orientación para avanzar en la implementación y permiten proyectar estrategias basadas en evidencia y con pertinencia contextual, que consideren e integren las iniciativas exitosas publicadas y los logros obtenidos.
Вода — как много в этом слове…, "Природа"
Authors: Наточин Ю.В.
Published: January 2024

Природа познания, выяснение взаимосвязи между сутью явлений и нашим чувственным восприятием, наукой и искусством рассматриваются на примере воды, которая составляет большую часть поверхности Земли, высока ее доля и в теле человека. Она радует глаз, служит предметом изучения разных наук, источником творческого вдохновения.
Men’s Sheds and Mental Health in Rural Communities: Exploring the Benefits of a Community-Level Program
Authors: Banack Clark , Whitfield Kyle Y. , Isley Serena
Published: January 2024

Rural regions across North America continue to suffer from a lack of community-level mental health supports. This exploratory study explores whether Men’s Sheds, bottom-up, community-driven groups designed to support retired and older men’s mental health by mimicking the social and collaborative aspects of “work-life” by creating opportunities to engage in project-based woodworking, metalworking or mechanics, are generating positive mental health outcomes for their members in rural communities in Alberta, Canada. Relying on a set of semi-structured interviews with participants across two rural Alberta Men’s Sheds, in addition to a sociodemographic and self-rating questionnaire, we demonstrate that the participants in these Sheds enjoy clear and significant mental health benefits by generating opportunities for camaraderie, a sense of purpose and a sense of inclusion. Although not an appropriate substitute for more formal mental health supports in certain situations, we conclude that supporting the formation of new Men’s Sheds throughout rural areas represents a worthwhile investment in the mental health of a group of vulnerable citizens.
Enhancing Literacy: A Comparative Analysis of the Effectiveness of Project Bear and Arangkada Pagbasa Reading Interventions in Claver National High School (S.Y. 2022-2024)
Authors: Salibay Maricel Ocon
Published: January 2024

This study evaluates the effectiveness of two reading intervention programs, PROJECT B.E.A.R and ARANGKADA PAGBASA, implemented in Claver National High School over two academic years (2022-2024). The Philippine Informal Reading Inventory (Phil-IRI) pretest initially identified many students as struggling readers. Post-intervention results indicated a marked improvement in reading skills, demonstrating the effectiveness of both programs. The study highlights the importance of collaborative efforts involving teachers, parents, and the local government unit (L.G.U.) in addressing reading difficulties. Comparative analysis of both programs offers insights into effective strategies for enhancing literacy among high school students.
Dynamics of Crop Diversification in Midlands of Kerala, India
Authors: Aiswarya G. B.  , Kshirsagar P. J.  , Banekol S. S.  , Bhosale S. S.  , Sawant M. S.
Published: January 2024

Aims: This study presents the extent of crop diversification as well as the reasons in the three districts of Kerala state; Thiruvananthapuram, Kottayam and Kannur which falls in the midland region of Kerala.

Methodology: Secondary data on area under cultivation of various crops for the time period of 2005-06 to 2020-21 was subjected to analysis using Simpson Index, Modified Entropy Index and Markov chain analysis.

Results: Kannur was found to be highly diversified with high value of Simpson Index of around 0.79 followed by Thiruvananthapuram with SI of around 0.74. Transitional probability matrix of Thiruvananthapuram revealed that coconut, spices and condiments retained more area in the district followed by non-food crops with an area retention. Non-food crops retained highest area followed by coconut, spices and condiments in Kottayam. More area occupying crop in Kannur was found to be non-food crops followed by coconut, spices and condiments. However, overall scenario in midland region showed that more area was occupied by non-food crops followed by coconut, spices and condiments.

Conclusion: The period from 2005-06 to 2020-21 showed changing pattern of acreage distribution in the three selected districts of Kerala with a declining trend in total cropped area and shift from food crops to non-food crops.
Metronidazole Induces the Metazoan Death of Giardia Trophozoites with the Aid of Pyruvate
Authors: Raj Dibyendu , Nozaki Tomoyoshi , Dutta Shanta , Ganguly Sandipan
Published: January 2024

Background: Metronidazole is the most common drug for the treatment of infectious agent Giardia. The trophozoites need to fight against the oxidative stress generated by metronidazole for their survival. It has been reported that trophozoites possesses several enzymes involved in response to oxidative stress like pyruvate-ferredoxin oxidoreductase, NADH oxidase, peroxiredoxin to combat the harsh condition. These enzyme systems generally act on the amitochondriate trophozoites to attenuate the reactive oxygen species generation which causes cytotoxicity but the actual mechanism of trophozoites death due to metronidazole treatment was still not clear.
Methods: The present study aims to establish the effects of pyruvate in Giardia trophozoites exposed to metronidazole treatment. Intracellular reactive oxygen species (ROS) production by Giardia trophozoite suspension was monitored in the presence and absence of pyruvate with the help of a dichlorodihydrofluoresceine diacetate (H2DCFDA) based assay. In the present study, we have investigated the effects of pyruvate on DNA damage in the trophozoites during metronidazole stress. We have also looked into the expression levels of some genes to show their relevance to metronidazole stress.
Results: The exogenously addition of physiologically relevant concentration of pyruvate was shown to elevate the rate of ROS generation in Giardia suspension under metronidazole stress. Our results provide evidence that exogenously added pyruvate have induced lipid peroxidation of stressed Giardia. Several known genes are modulated due to the exposure of metronidazole in trophozoites.
Conclusion: These results suggest that pyruvate is the key regulatory metabolite that helps generation of different radicals to initiate apoptotic like death in Giardia trophozoites during metronidazole exposure.
Identification of early signs of change/mental disorders in puerpera to promote self-care / Identificação de sinais precoces de alteração/ transtornos mentais em puérperas para promoção do autocuidado
Authors: Silva Jéssica Kelly Alves Machado da , Santos Amuzza Aylla Pereira dos , Pontes Crislane de Oliveira , Silva Jovânia Marques de Oliveira e , Nascimento Yanna Cristina Moraes Lira , Santos Clarice Isabel Rosa dos
Published: January 2024

Objetivo: identificar sinais precoces de alterações e/ou transtornos mentais em puérperas para promoção do autocuidado. Método: a população estudada foram puérperas atendidas na unidade básica de saúde. Resultados: as puérperas participantes enquadram-se como mulheres em idade reprodutiva, classificadas como mães adolescentes e mães adultas jovens. São mulheres que reconhecem a necessidade da prática do autocuidado, mas que possuem alguns entraves ligados às mais diferentes realidades e cotidiano em que estas estão inseridas, tornando fatores de risco para transtornos/alterações mentais durante o ciclo gravídico-puerperal.  Conclusões: a efetivação da assistência integral à saúde das mulheres, ocorridas durante o pré-natal, parto e nascimento, são condições essenciais para a prevenção de transtornos e doenças mentais ocorridos numa fase tão ímpar que é o período puerperal.
Mechanical and surface properties of polysulfide‐based polyurea modified with aminoethylaminopropyl poly(dimethylsiloxane)
Authors: Quan Yi Wu , Wang Qing Jun , Fang Jiang Ling , Chen Qing Min
Published: November 2002

A series of polysulfide‐based polyureas with different siloxane contents were synthesized, and they were based on isophorone diisocyanate, liquid polysulfide oligomer, aminoethylaminopropyl poly(dimethyl siloxane) (AEAPS), and 2,5‐diamino‐3,6‐dimethylmercapto‐toluene. The mechanical and surface properties were investigated with attenuated total reflectance Fourier transform infrared spectroscopy, surface contact angles, electron spectroscopy for chemical analysis, and stress–strain analysis. Siloxane was enriched on the surfaces of these elastomers, and the tensile properties of the elastomers did not change markedly with the AEAPS modification. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 584–588, 2003
Synthesis of novel reactive coalescing agents and their application in a latex coating
Authors: Lahtinen Maarit , Glad Essi , Koskimies Salme , Sundholm Franciska , Rissanen Kari
Published: November 2002

The syntheses and the performance of five glycidyl compounds as novel reactive coalescing agents are presented. The reactive coalescing agents were synthesized with moderate yields, structures were verified using spectroscopic methods, and the properties of glycidyl compounds such as boiling points and evaporation rates were measured. The applicability of five glycidyl compounds as reactive coalescing agents was tested in characterized carboxyl functional latex. Properties like pendulum hardness, gloss, and efficiency of the glycidyl compound to reduce the minimum film‐formation temperature (MFFT) of the latex were measured from the cured latex films. The application test results were compared to the commercial nonreactive coalescing agent, Nexcoat™ 795. The films with synthesized reactive coalescing agents with carboxyl functional latex were found to have good pendulum hardness and excellent gloss. Also, the efficiency of three glycidyl compounds in lowering the MFFT of the latex was competitive with the commercial coalescing agent. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 610–615, 2003
Utilization of lignocellulosic fibers in molded polyester composites
Authors: Hassan Mohammad L. , Nada Abd‐Alla M. A.
Published: November 2002

Using rice straw, bagasse, and cotton stalk fibers as reinforcing fillers in polyester composite was studied. The effects of fiber loading and fiber size on the modulus of rupture (MOR), modulus of elasticity (MOE), tensile strength, water absorption, and thickness swelling were investigated as well. The effect of esterification using maleic anhydride on the aforementioned properties also was studied. Ultraviolet light resistance and thermal behavior of the produced composites were also investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 653–660, 2003
Effects of single‐walled carbon nanotubes on the crystallization behavior of polypropylene
Authors: Valentini L. , Biagiotti J. , Kenny J. M. , Santucci S.
Published: November 2002

Polypropylene matrix composites reinforced with single‐walled carbon nanotubes (SWNTs) were produced with different nanotube concentrations. The characterization of these new materials was performed by differential scanning calorimetry and Raman and Fourier transform infrared spectroscopy to obtain information on the matrix–nanotube interaction, on the crystallization kinetics of polypropylene, and especially on the macrostructure and organization of the nanotubes in the composite. On the one hand, the results confirmed the expected nucleant effect of nanotubes on the crystallization of polypropylene, but on the other hand, this effect was not linearly dependent on the SWNT content: there was a saturation of the nucleant effect at low nanotube concentrations. Raman spectroscopy was successfully applied to demonstrating that in the composite films, the crystallization kinetics were strongly affected by the distance between the nanotube bundles as a result of a different intercalation of the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 708–713, 2003
Lateral variation within a hiatal‐condensed bed and the controls on the formation and occurrence of berthierine ooids: a case study from the Middle Jurassic of NE England, UK
Authors: Williams M.E.
Published: November 2002

Shallow‐marine sandstone and berthierinic, ooidal, sandy limestone form the Hackness Rock Member (HRM), a Callovian‐age hiatal‐condensed bed in NE England. The HRM was deposited in response to a rise in relative sea‐level. Apart from the major hiatal surfaces represented by two significant non‐sequences, it contains a number of other hiatal surfaces representing shorter periods of time. Although the HRM has its own distinctive bioclastic concentrations, early diagenetic mineral assemblages and specific types and degrees of bioturbation, the expression of this bed is variable even over short distances.

Variations in the topography of the sea floor produced local hollows and highs, which account for the lateral variability of the HRM and controlled where berthierine ooids formed. Hollows created ‘clastic/colloidal’ traps where finer‐grained sediment accumulated and had low physical mobility; these conditions favoured intra‐sedimentary growth of berthierine ooids in an early (sub‐oxic) diagenetic environment. In contrast, highs were more susceptible to storm reworking and material was more mobile; these conditions resulted in a lower overall rate of accumulation and a lower degree of shallow, sub‐surface diagenesis. Copyright © 2002 John Wiley & Sons, Ltd.
Role of human heme oxygenase‐1 in attenuating TNF‐α‐mediated inflammation injury in endothelial cells
Authors: Kushida Taketoshi , Volti Giovanni Li , Quan Shuo , Goodman Alvin , Abraham Nader G.
Published: November 2002

Heme oxygenase (HO) is the rate‐limiting enzyme in the formation of bilirubin, an antioxidant, and carbon monoxide (CO), a cell cycle modulator and a vasodilator. Cyclooxygenase (COX) is a hemeprotein that catalyzes the conversion of arachidonic acid (AA) to various prostanoids, which play an important role in the regulation of vascular endothelial function in normal and disease states. The influence of suppression or overexpression of HO isoforms on COX expression and synthesis of prostanoids is of considerable physiological importance. Consequently, the goal of the present study was to determine whether the heme‐HO system regulates COX enzyme expression and activity in vascular endothelial cells in the absence and presence of TNF‐α (100 ng/ml). Endothelial cells stably transfected with the retrovirus containing the human HO‐1 gene exhibited a several‐fold increase in HO‐1 protein levels, which was accompanied by an increase in HO activity and a marked decrease in PGE2 and 6‐keto PGF1α levels. We also assessed the effect of retrovirus‐mediated HO‐1 gene transfer in the sense and antisense orientation on HO‐1 expression and cell cycle progression in human endothelial cells. The levels of CO and HO activity were increased in cells transduced with the HO‐1 sense and were greatly suppressed in cells transduced with HO‐1 antisense as compared to control sham‐transduced cells (P < 0.05). The percentage of the G1‐phase in cells transduced with HO‐1 significantly increased (41.4% ± 9.1) compared with control endothelial cells (34.8% ± 4.9). We measured COX activity by determining the levels of PGI2 and PGE2. The levels of PGI2 decreased in cells transduced with HO‐1 sense and increased in cells transduced with HO‐1 in antisense orientation. The expression of p27 was also studied and showed a marked decrease in cells transduced with HO‐1 sense and a marked increase in the HO‐1 antisense transduced cells. Cell cycle analysis of endothelial cell DNA distributions indicated that the TNF‐α‐induced decrease in the proportion of G1‐phase cells and increase in apoptotic cells in control cultures could be abrogated by transfection with HO‐1 in the sense orientation. Tin mesoporphyrin (SnMP) reversed the protective effect of HO‐1. These results demonstrate that overexpressing HO‐1 mitigated the TNF‐α‐mediated changes in cell cycle progression and apoptosis, perhaps by a decrease in the levels of COX activity. J. Cell. Biochem. 87: 377–385, 2002. © 2002 Wiley‐Liss, Inc.
Anchorage‐independent phosphorylation of p130Cas protects lung adenocarcinoma cells from anoikis
Authors: Wei Lin , Yang Yu , Zhang Xin , Yu Qiang
Published: November 2002

The regulation and function of the signaling adaptor protein p130Cas in tumor cell anchorage‐independent survival, or anoikis resistance, were investigated in human lung adenocarcinoma cells. The tyrosine phosphorylation and function of p130Cas during cell detachment were analyzed in tumor cells and compared with that of normal epithelial cells. Cell detachment trigged rapid dephosphorylation of p130Cas in the nontumorigenic and anoikis‐sensitive normal epithelial cells, but had no effect on the tyrosine phosphorylation of p130Cas in the anoikis‐resistant lung adenocarcinoma cells. Further analysis revealed that the total tyrosine kinase activities associated with p130Cas in the lung tumor cells are anchorage‐independent and are significantly higher than that in the normal cells, in which the p130Cas‐associated tyrosine kinase activities are anchorage‐dependent. Analysis of two known p130Cas‐associated tyrosine kinases FAK and Src indicated that the regulation of tyrosine phosphorylation of FAK and Src are altered in the tumor cells. Inhibition of Src specifically abolished phosphorylation of p130Cas and induced anoikis. Furthermore, overexpression of dominant‐negative forms of p130Cas also induced apoptosis. Taken together, these data suggest that p130Cas mediates a cell survival signal from cell–matrix interaction. Alterations in tumor cells that lead to constitutive phosphorylation of p130Cas can prevent cells from anoikis, hence contribute to tumor cell anchorage independence and metastasis. J. Cell. Biochem. 87: 439–449, 2002. © 2002 Wiley‐Liss, Inc.
Structurally adaptive hot spots at a protein interaction interface on TRAF3
Authors: Ely Kathryn R. , Li Chenglong
Published: November 2002

Tumor necrosis factor (TNF) signaling is controlled by receptors and intracellular signaling pathways that activate the NF‐κB transcription factor. The resulting signals elicit immune responses and have important implications for disorders such as autoimmunity or allergic reactions. TNF‐receptor‐associated factors (TRAFs) bind to the cytoplasmic portion of TNFRs as well as downstream regulators and thus are co‐inducers of the signal transduction. TRAF3 binds to diverse receptors and regulators by accomodating a conserved motif that is embedded in completely different structural frameworks. Thus, the protein–protein contact region on TRAF3 represents a binding interface that is structurally and functionally adaptive. In this report, three ‘hot spots’ at the TRAF3 protein–interaction interface are defined that provide the principal contact regions for different binding partners. The side‐chains of residues at these ‘hot spots’ are flexible and undergo movements on binding the different partners. These side chain rearrangements provide a structural adaptability that promotes interaction with a variety of distinct proteins. It is proposed that similar adaptive ‘hot spots’ are also present on the binding surfaces of TRAF1, TRAF2 and TRAF5. Copyright © 2002 John Wiley & Sons, Ltd.
Planar antenna array design with a multi‐purpose GA‐based procedure
Authors: Caorsi Salvatore , Lommi Andrea , Massa Andrea , Piffer Stefano , Trucco Andrea
Published: November 2002

This paper deals with the synthesis of planar arrays. In the framework of iterative search procedures, a method based on a genetic algorithm (GA) is presented. Starting from the definition of a suitably defined cost function, thinning and weighting a randomly generated array configuration, the multi‐purpose stochastic procedure is able to satisfy various antenna constraints to determines an optimal trade‐off among contrasting requirements. In order to confirm the reliability of the proposed approach (also in comparison with the related literature), some highly optimized antenna array designs are reported and discussed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 428–430, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10629
Array beam scanning by element frequency tuning
Authors: Shafai L. , Daneshmand M.
Published: November 2002

The relationship between the resonance frequency of an antenna and the phase of its radiated field is established, indicating that the frequency or dimensional tuning may be used for beam scanning of the arrays. For microstrip patch antennas the range of far field phase variation within the element bandwidth is determined. Examples for limited beam scans of four element arrays are considered and studied. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 430–434, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10630
New CAD model to calculate the resonant frequency of inverted microstrip circular patch antennas
Authors: Guha Debatosh , Siddiqui Jawad Y.
Published: November 2002

In this paper, a new CAD model is proposed to calculate accurate resonant frequencies of inverted microstrip circular patch antennas having a wide range of parameters. This model incorporates all the effects of various dimensions and dielectrics used. Computed results for the first few modes are compared with some new measurements. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 434–437, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10631
Two‐arm microstrip spiral antenna with a circular aperture on the ground plane
Authors: Oh Daeyoung , Kim Myungki , Park Ikmo
Published: November 2002

This paper presents a two‐arm microstrip spiral antenna with a circular aperture on the ground plane that produces either an axial beam or a tilted beam, depending on the operating frequency. A 50‐Ω microstrip feedline is divided into two 100‐Ω lines that feed the spiral antenna from the outer end of the spiral arms with a 180° phase difference at fo. The antenna is realized on a planar form without any balun circuit using a microstrip structure, which is easily compatible with millimeter‐ and microwave‐integrated circuits. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 453–455, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10636
Mutual impedance formula between patch antennas based on synthetic asymptote and variable separation
Authors: Sun Y. X. , Chow Y. L. , Fang D. G.
Published: November 2002

A formula for mutual impedance between patch antennas is constructed based on the physics of the static near field and the radiation far field of the couplings. This leads to asynthetic asymptoteform [1] of separated variables of the center‐to‐center distancerand the azimuth angle ϕ. Only 12 coefficients are to be determined by matching with a full‐wave analysis through commercial software, such as IE3D. Our formula is accurate and complete, with no restriction on the detailed structures of patch, feed, and substrate. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 466–470, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10640
Photonic band gap studies on periodic metallic structures in the microwave region
Authors: Tiwari Manoj K. , Gupta K. K. , Gupta H. C. , Dube D. C.
Published: November 2002

We present our experimental findings on microstrip‐type metallic photonic band gap (PBG) periodic structures prepared using a commercial aluminum foil. Effect of change in geometry of the periodic dielectric structure, namely, period, rectangular hole length, and defect on PBG, is studied. It is found that as the rectangular‐hole‐cut dimension decreases in terms of length, the lower edge of the band gap decreases toward the lower frequency side of the microwave region. It is also observed that as the defect length increases, the band gap edge again shifts toward the lower frequency side. These findings of band gap with air as substrate confirm the role of wave impedance in purely metallic periodic structures. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 483–486, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10644
Influence of birefringence on soliton switching in a twin‐core fiber coupler
Authors: Li Hong , Huang Dexiu , Wang D. N.
Published: November 2002

In this paper, the effects of randomly varying birefringence on soliton switching in a twin‐core fiber coupler are discussed in detail by numerical simulation. The results obtained show that these effects on sub‐ps soliton switching cannot be neglected, they would degrade the quality of the coupler. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 502–506, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10649
Theoretical justification of empirical additivity schemes for conformational energies
Authors: Šatkovskienė D.
Published: November 2002

Additivity of conformational energy of saturated molecules has been studied using the perturbation theory for density matrix. Analytical expressions for both total and conformational energies have been obtained and analyzed up to the third‐order members. It is shown that the conformational energy of compounds under investigation can be presented as a sum of transferable increments corresponding to the energies of separate conformational segments and their sequences. The role of end groups in determination of energies of conformational segments is revealed. The influence of substitution has been investigated. The dependence of subtle conformational effects on common structural peculiarities of Hamiltonians of saturated molecules has been concluded. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Computation of two‐center Coulomb integrals over Slater‐type orbitals using elliptical coordinates
Authors: Özmen Ayhan , Karakaş Asli , Atav Ülfet , Yakar Yusuf
Published: November 2002

A general analytic formula is obtained for the two‐center Coulomb integrals over Slater‐type orbitals in elliptical coordinates. Finite series expansions are used in the evaluation of the radial part of the integrals. The analytic formula is expressed in terms of a product of the well‐known auxiliary functions Ak(p) and Bk(p) and incomplete gamma functions. Recursive relations for the computer evaluation of these functions are given as well. The recursive relations are stable and our computer results are in good agreement with the benchmark values given in the literature. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Linear inequalities for density matrices: III
Authors: Davidson Ernest R.
Published: November 2002

Diagonal linear inequalities are derived for three‐ and four‐body reduced density matrices. These give a different insight into the previous derivations of linear inequalities for the two‐body reduced density matrix. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Characterization of molecular complexity
Authors: Randić Milan , Plavs̆ić Dejan
Published: November 2002

We put forward a novel index of molecular complexity, ξ, taking into account the symmetry of a molecular graph and the specificity of structural components considered. The ξ index is defined as the sum of augmented valences of all mutually nonequivalent vertices in a molecular graph. The augmented valence of a vertex in a graph is the sum of its valence and valences of all neighboring vertices with the weight 1/2d depending on their distance, d, from the vertex. The ξ index is examined on the set of octane isomers and some special classes of graphs. It is also compared with a certain number of alternative complexity measures considered in the literature. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Automated test case generation for the stress testing of multimedia systems
Authors: Zhang Jian , Cheung S. C.
Published: November 2002

With the advancement in network bandwidth and computing power, multimedia systems have become a popular means for information delivery. However, general principles of system testing cannot be directly applied to testing of multimedia systems on account of their stringent temporal and synchronization requirements. In particular, few studies have been made on the stress testing of multimedia systems with respect to their temporal requirements under resource saturation. Stress testing is important because erroneous behavior is most likely to occur under resource saturation. This paper presents an automatable method of test case generation for the stress testing of multimedia systems. It adapts constraint solving techniques to generate test cases that lead to potential resource saturation in a multimedia system. Coverage of the test cases is defined upon the reachability graph of a multimedia system. The proposed stress testing technique is supported by tools and has been successfully applied to a real‐life commercial multimedia system. Although our technique focuses on the stress testing of multimedia systems, the underlying issues and concepts are applicable to other types of real‐time systems. Copyright © 2002 John Wiley & Sons, Ltd.
Lessons learned from automating tests for an operations support system
Authors: Fecko Mariusz A. , Lott Christopher M.
Published: November 2002

We present experience gained in automating tests for an operations support system. A major portion of the effort was devoted to extending a commercial test tool so that testers could easily manipulate graphical user interface (GUI) objects on two implementations of the application. For this purpose, we developed a test automation library as support infrastructure for writing tests. The challenges and tradeoffs are discussed such as simplicity/complexity for a tester versus a library developer, hiding/exposing window hierarchy to the tester, providing common methods for different types of GUI objects, transparently manipulating custom GUI widgets, and coping with data‐dependent test cases. We discuss the requirements of test code reusability, maintainability, and portability, and describe the solutions we found. In addition, we offer observations about benefits and pitfalls of test automation, our recommendations for maximizing return on investment, and results from automating a variety of tests. Copyright © 2002 John Wiley & Sons, Ltd.
Size and Political Trust: Evidence from Denmark, the Netherlands, Norway, and the United Kingdom
Authors: Denters Bas
Published: November 2002

This paper deals with two questions on the relations between the size of political systems and political trust. First, does citizens' trust in national elected officials differ from their trust in local elected officials? Second, what is the relationship between citizens' trust in elected local government officials and the size of local government units? These questions were answered on the basis of survey data from Denmark, the Netherlands, Norway and the United Kingdom. We found that trust in local officeholders is typically and often considerably higher than trust in national politicians. Moreover, the evidence from these four countries suggests that size of municipality has a modest negative effect on political trust. Further evidence suggests that this negative effect is the result of a tendency of citizens in small municipalities to be more satisfied with their local government than residents in large units. This further evidence also shows that whatever its origins (intensive personal relations or a dense network of civil organisations) social trust is not vital for an adequate understanding of political trust.
The costs and benefits of the Internet as a marketing and communications tool: the attitudes, perceptions and experiences within the non‐profit environmental sector in Scotland
Authors: Illingworth Lorraine , Williams Dorothy , Burnett Simon
Published: November 2002

Discusses the findings of a study investigating the attitudes, perceptions and experiences of Scottish non‐profit environmental organisations and the costs and benefits of the Internet as a marketing and communications tool. Aims to ascertain whether the size of the organisation and the level of Internet use determines the perceptions and beliefs of non‐profit organisations within the environmental sector in Scotland and whether these factors also determines the costs and benefits experienced by Internet users. Finds that regardless of size or the level of use, organisations believe the Internet is a cost‐effective way to market their organisations and promote awareness. However, attitudinal factors affect the level of use by small organisations. Overall the organisations within the sample have indicated that the Internet is a low cost, high benefit marketing solution.
Household ecological footprinting for active distance learning and challenge of personal lifestyles
Authors: Crompton Sally , Roy Robin , Caird Sally
Published: November 2002

This paper introduces a new distance learning course, “Working with our environment: technology for a sustainable future”. An inter‐disciplinary team within the Technology Faculty of the Open University developed this undergraduate course, which enrols over 1,500 students per year. One of the overall course aims is to help students understand how the use of technology to meet human material needs contributes to environmental effects. The process of producing this course, its philosophy, aims and design will be briefly discussed. At the start of the course a lifestyle environmental assessment activity, called EcoCal, is integrated within students’ study materials. The activity enables students to assess the main impacts on the environment arising from their own households’ consumption of transport, energy, food and water and production of waste. Through the use either of a printed questionnaire or publicly available software students can calculate their “ecological footprints” and then consider and model the effects of changes to their lifestyles. Through the combination of undertaking this activity and submitting an appropriate assignment, students are encouraged to think critically and creatively about their personal and household impacts on the environment and how these might be reduced. At the end of the course students are surveyed to explore whether their attitudes and behaviour have changed.
New sources of clustering in the digital economy
Authors: Romano Aldo , Passiante Giuseppina , Elia Valerio
Published: November 2002

Using a sample of 29 virtual clusters, the paper examines new sources of clustering in the digital economy. The “virtual cluster” phenomenon highlights the most significant effect of the development of the information and communication technologies in the business environment. A virtual cluster is conceived as an e‐business community, made up of customers, suppliers, distributors and commerce providers sharing digital and knowledge networks for collaboration and competition. The purpose of this paper is to set out the characteristics of a new competitive space, in which a strategic role is played by virtual processes among partners, and to review the traditional sources of clustering in the digital economy environment (Romano et al., 1999). More specifically, this paper attempts to show the emerging overlap between digital and knowledge networks, which generates a new competitive space within a new global‐virtual learning environment. Finally, assuming that traditional sources of clustering are generally identified in specialisation (based on a sophisticated division of labour) and geographic proximity, the paper discusses how the role of organisational proximity acts as a substitute for geographic proximity in supporting coordination and tacit knowledge exchange. As it emerges from the analysis of our cases, from a managerial point of view, organisational proximity may be achieved through the implementation of supply chain management (SCM) and customer relationship management (CRM) strategies. An earlier version of this paper was presented at the 23rd Institute of Small Business Affairs Annual Resource and Policy Conference in November 1999 in Leeds, UK.
The role of non‐executive directors in UK SMEs
Authors: Berry Aidan , Perren Lew
Published: November 2002

Influential reports combined with media attention on directors’ remuneration has sparked academic and practitioner interest in the whole area of corporate governance. Cadbury’s suggestion to strengthen the independent governance role has led to particular interest in non‐executive directors (NEDs). More recently, the role of NEDs in the governance of small and medium‐size enterprises (SMEs) has started to generate attention, and a number of registers of NEDs are established. Indeed, the role of NEDs in SMEs received special attention in the recent Hampel report (1998). Until recently, only two papers directly addressed the role of NEDs in SMEs; both papers were by Mileham and used data obtained from a survey concerned with the role of NEDs carried out with Institute of Management members. This research made a useful contribution, but had a number of limitations. More recently, the increased interest in the role of NEDs in SMEs has sparked further research, but there is still a need for an overall picture of NED and mentor involvement in UK SMEs. The research in this paper addresses this need by presenting the results from a survey sent to 5,279 UK SMEs selected from the Yellow Pages Business Database. The questionnaire was designed to provide a general overview of NED and mentor involvement in SMEs and to allow the following questions to be answered: How many SMEs have NEDs, and are there any firm size patterns? Are there firm age patterns? Are there firm sector patterns? Does firm size influence the formality of NED procedures? What does the managing director believe NEDs add? Are firms with NEDs more successful than those without a NED? Does the profile of the managing director matter? Does a firm’s size influence NED involvement? How do firms acquire NEDs? Why do some SMEs not have NEDs? The paper presents these findings and explores the implications for SMEs and policy advisors.
The impact of the Web on the stockbroking industry: Big Bang 2
Authors: Scullion Martin , Nicholas David
Published: November 2002

An investigation of what effect online trading is having on the traditional stockbrokerage industry. There have been lots of discussions and articles written over the last couple of years debating whether the traditional stockbrokerage model is about to be upstaged by the new online version touted by the online brokerage industry. With so many diverse views being portrayed it is difficult to fully gauge the real impact that online trading is having on the traditional stock brokerage industry. A large‐scale questionnaire and interview study was conducted to get some answers.
The global digital divide; beyond hICTeria
Authors: Menou Michel J.
Published: November 2002

Questions the values and wisdom of those proposing to tackle the global digital divide. Why, for instance, the concern for the digital divide and not the health divide? Questions too the methods for determining and measuring the divide and the naive assumption that the Internet itself can transform the destinies of the digitally poor. What is really at issue is not finding the best way of bringing the Internet to the poor, but finding the best way for the poor to take advantage of the Internet in order to improve their lot.
Health kiosk use: a national comparative study
Authors: Nicholas David , Huntington Paul , Williams Peter
Published: November 2002

Provides an initial analysis of the use of InTouch with Health touch screen information kiosks located throughout the UK. Presents data for more than 50 kiosks and models use to a variety of variables. The data were collected via kiosk transaction logs and questionnaire. Seeks to explain use differences between kiosks. The amount of kiosk use and the number of kiosk users were explained in terms of both neighbourhood factors and kiosk host factors. Significant variables determining the amount of use and number of users include the size of the kiosk host organisation and whether intermediary help is available to the kiosk user, either from a health professional or a receptionist. The general economic well‐being of the area was found to be significant in explaining the length of session time, while word of mouth and help from other users was a significant variable explaining the number of session pages viewed.