bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluating the law of the wall in two-dimensional fully developed turbulent channel flows
Authors: Zanoun E.-S. , Durst F. , Nagib H.
Published: September 2003

This article is concerned with the mean velocity distributions of two-dimensional fully developed turbulent plane-channel flows. To yield reliable information, the authors performed detailed hot-wire measurements for more than 12 Reynolds numbers. The experimental investigations covered a wide range of the Reynolds numbers up to Reτ≈5×103, where Reτ is based on the wall friction velocity and the channel half-height. From the distribution of the mean velocity gradient (dU+/dy+)=f(y+) the entire flow field was analyzed, resulting in a logarithmic region for the mean velocity profile in the inertial sublayer, extending almost up to the center of the channel at higher Reynolds numbers. The analysis of the experimental results yield a value of the von Kármán constant, κ, close to 0.37(≈1/e) independent of the Reynolds number and the additive constant B=3.70, which is close to 10/e, i.e., U+=e ln y++10/e=(1/0.37)ln y++3.70.
Electrical and physical properties of HfO2 films prepared by remote plasma oxidation of Hf metal
Authors: Yamamoto Kazuhiko , Hayashi Shigenori , Niwa Masaaki , Asai Masayuki , Horii Sadayoshi , Miya Hironobu
Published: September 2003

The electrical and physical properties of thin hafnium oxide (HfO2) films fabricated by a remote plasma oxidation of a hafnium metal were investigated. The HfO2 capacitors with TiN electrodes exhibited excellent electrical characteristics such as equivalent oxide thickness (EOT) of 0.65 nm with leakage current density of 2.7 A/cm2 at the gate bias of Vfb-1 (V). The HfO2 thickness dependence of the EOT demonstrated that the permittivity of 19 for HfO2 layer and the interfacial layer thickness of 0.36 nm. X-ray photoelectron spectroscopy study revealed that the oxygen radicals oxidize the Hf metal selectively than Si substrate, leading to an increase of permittivity of HfO2 with reduced interfacial layer growth.
Oxide-assisted growth and characterization of Ge/SiOx nanocables
Authors: Meng Xiang-Min , Hu Jun-Qing , Jiang Yang , Lee Chun-Sing , Lee Shuit-Tong
Published: September 2003

Germanium/SiO x nanocables were prepared via simple thermal evaporation of SiO and Ge powders in an alumina tube with Ar premixed with 5%H2 as the carrier gases. The product was characterized by scanning electron microscopy, transmission electron microscopy (TEM) with energy dispersive x-ray spectroscopy system, and high-resolution TEM. The Ge/SiOx nanocables had diameters in the range of 60–150 nm and lengths of several tens of micrometers. The growth of the Ge/SiOx nanocables was considered to occur via the combination of oxide-assisted growth and vapor–liquid–solid processes, and the composition of the nanocables was determined by the relative supply of the Ge and SiO vapors.
Ultraviolet light selective photodiode based on an organic–inorganic heterostructure
Authors: Yamaura J. , Muraoka Y. , Yamauchi T. , Muramatsu T. , Hiroi Z.
Published: September 2003

We show a perfect ultraviolet (UV) light selective and sensitive photovoltaic cell easily fabricated. The device consists of a water-soluble p-type semiconducting polymer PEDOT-PSS: poly(3,4-ethylenedioxythiophene) doped by poly(4-styrenesulfonate) film deposited on a Nb-doped titanium oxide (SrTiO3:Nb) substrate. For the PEDOT-PSS/SrTiO3:Nb heterostructure, the photosensitivity at zero bias for the UV light with L=1 mW/cm2 is estimated to be 0.05 A/W, corresponding to a quantum yield of 16% electron/photon. This device is only activated in the UV region (λ<390 nm), and then, it exhibits a large response to the UV–B light (290–320 nm).
Sharp exciton emission from single InAs quantum dots in GaAs nanowires
Authors: Panev Nikolay , Persson Ann I. , Sköld Niklas , Samuelson Lars
Published: September 2003

We have performed photoluminescence spectroscopy on single GaAs nanowires with InAs quantum dots in the form of thin slices of InAs, possibly alloyed with Ga as InGaAs, incorporated into the GaAs. The nanowires were grown by chemical beam epitaxy using gold nanoparticles as catalysts. The photoluminescence measurements showed rich spectra consisting of sharp lines with energies and excitation power dependency behavior very similar to that observed for Stranski–Krastanow-grown InAs/GaAs quantum dots. By reducing the excitation power density we were able to obtain a quantum dot spectrum consisting of only one single sharp line—the exciton line.
Electron dynamics in InNxSb1−x
Authors: Mahboob I. , Veal T. D. , McConville C. F.
Published: September 2003

Electron transport properties in InNxSb1−x are investigated for a range of alloy compositions. The band structure of InNxSb1−x is modeled using a modified k⋅p Hamiltonian. This enables the semiconductor statistics for a given x value to be calculated from the dispersion relation of the E− subband. These calculations reveal that for alloy compositions in the range 0.001⩽x⩽0.02 there is only a small variation of the carrier concentration at a given plasma frequency. A similar trend is observed for the effective mass at the Fermi level. Measurements of the plasma frequency and plasmon lifetime for InNxSb1−x alloys enable the carrier concentration and the effective mass at the Fermi level to be determined and a lower limit for the electron mobility to be estimated.
Formation of Large Opals via Drying of Wet Colloidal Crystals
Authors: Salgueiriño-Maceira Verónica , Rodríguez-González Benito , Hellweg Thomas , Liz-Marzán Luis M.
Published: September 2003

The formation of opal structures with large crystalline domains is demonstrated through the formation of colloidal crystals in ethanol of surface-modified colloidal silica spheres containing small CdS nuclei, followed by controlled drying at room temperature. The high quality of the opals was characterized by scanning electron microscopy (SEM) and, more importantly, also by small-angle neutron scattering (SANS), which allows probing of the entire sample and provides important information on the crystal structure.
Flash NanoPrecipitation of Organic Actives and Block Copolymers using a Confined Impinging Jets Mixer
Authors: Johnson Brian K. , Prud'homme Robert K.
Published: September 2003

A new technology to form nanoparticles of hydrophobic organic actives at high concentration and yield, as well as methods to characterize the process, are presented. In Flash NanoPrecipitation, an organic active and an amphiphilic diblock copolymer are molecularly dissolved in an organic phase and mixed rapidly with a miscible anti-solvent to afford precipitation of the active with a tunable, narrow submicron particle size distribution from 1 μm to 80 nm. The enabling components are a novel ‘analytical’ (quantified mixing time) confined impinging jets (CIJ) mixer for millisecond stream homogenization and amphiphilic diblock copolymers which alter the organic nucleation and growth, provide steric stabilization for the particles, and offer a functional surface for the particle. Applications in enhanced pharmaceutical delivery, dye preparation, and pesticide formulation are specifically targeted.
Hydrogen-Bonded Macrocluster Formation of 1-Propanol and 2-Propanol on Silica Surfaces
Authors: Mizukami Masashi , Kurihara Kazue
Published: September 2003

We have investigated the adsorption of 1- and 2-propanol on silica surfaces from their mixtures with cyclohexane using a combination of colloidal probe atomic force microscopy, adsorption excess isotherms, and FTIR spectroscopy in the ATR mode. The adsorption isotherm indicated that a similar amount of each alcohol was adsorbed on the silica surfaces. FTIR spectra revealed that 1-propanol adsorbed on the surface employing hydrogen-bonding between the surface silanol groups and the hydroxyl groups of 1-propanol as well as between the hydroxyl groups of 1-propanol in the form of a linear zig-zag structure. This structure is similar to the linear hydrogen-bonded structure of ethanol, which we have found on silica and called a ‘surface molecular macrocluster’ (M. Mizukami, M. Moteki, K. Kurihara, J. Am. Chem. Soc. 2002, 124, 12 889). The contact of adsorbed layers of 1-propanol on the opposed silica surfaces brought about the long-range attraction extending to 69 ± 9 nm at 0.1 mol-% 1-propanol. 2-Propanol was also adsorbed on the surface by the hydrogen-bonding, however, in the form of a cyclic structure. No long-range attraction was observed in the 2-propanol/cyclohexane binary liquids at 0.1–6.0 mol-%. The absence of a long-range attraction can be explained by the cyclic aggregation structure of 2-propanol on the surface.
A revision of the Australasian species of Dicranoloma (Bryophyta, Dicranaceae)
Authors: Klazenga Niels
Published: September 2003

A revision of the Australasian (Australian and New Zealand) species of Dicranoloma (Renauld) Renauld is presented. Fifteen species are accepted: Dicranoloma austroscoparium (Müll.Hal. ex Broth.) Watts & Whitel., D. billarderi (Brid. ex anon.) Paris, D. braunii (Müll.Hal. ex Bosch & Sande Lac.) Paris, D. daymannianum E.B. Bartram, D. diaphanoneuron (Hampe & Müll.Hal.) Paris, D. dicarpum (Nees) Paris, D. eucamptodontoides (Broth. & Geh.) Paris, D. fasciatum (Hedw.) Paris, D. leichhardtii (Hampe) Watts & Whitel., D. menziesii (Taylor) Renauld, D. obesifolium (R.Br.bis) Broth., D. platycaulon Dixon, D. plurisetum Dixon, D. robustum (Hook.f. & Wilson) Paris and D. trichopodum (Mitt.) Broth. Fifteen new synonymies were made. New lectotypifications have been made where necessary. Thirteen species occur in Australia and 10 in New Zealand. D. austroscoparium, D.�diaphanoneuron and D. leichhardtii are endemic to Australia, while D. plurisetum and D. obesifolium are endemic to New Zealand. Moreover, D. platycaulon, D. fasciatum and D. trichopodum are endemic to the region. D. daymannianum and D. fasciatum are newly reported from Australia. All recognised species are described and illustrated and distribution maps and a key to the species have been provided.
Acid buffering capacity and potential acidification of cotton soils in northern New South Wales
Authors: Singh Balwant , Odeh I.O.A. , McBratney A. B.
Published: September 2003

Soil acidity has been of major concern in Australia since European settlement. Acidification processes have been accelerated due to agricultural activities such as N fertiliser application and leguminous N-fixation in farm rotations. In this paper, we measured the acid buffering capacity (pHBC) of Vertosols, soils used predominantly for growing cotton in northern New South Wales. The pHBC values were used to calculate decrease in soil pH assuming net acid input due to agricultural practices. We combined the acidification results with geostatistics to spatially simulate the decline in soil pH of surface soils over time. The results indicate that it would take 10–417 years for soil pH to decrease by 1 unit on an assumed acid input of 5�kmol�H+/ha.year. Soil pH will drop by 1 unit within 100 years for 90% of the soils and within 15 years for 10% of the soils. This reflects the variability of the pHBC for the studied soils. In 50 years from present, most of the eastern and north-western parts of the study region may become highly acidic with soil pH declining to 5.5. There may be a potential threat to sustainable agriculture from acidification in the region, although more work needs to be done to corroborate the counter-effects of water fluxes and carbonate dissolution. Sensitivity analysis indicates that even at low levels of acid input, some areas in the study region may experience significant decline in soil pH in the surface layer.
Mathematical modelling of the cellular mechanics of plants
Authors: Bruce David M.
Published: September 2003

The complex mechanical behaviour of plant tissues reflects the complexity of their structure and material properties. Modelling has been widely used in studies of how cell walls, single cells and tissue respond to loading, both externally applied loading and loads on the cell wall resulting from changes in the pressure within fluid–filled cells. This paper reviews what approaches have been taken to modelling and simulation of cell wall, cell and tissue mechanics, and to what extent models have been successful in predicting mechanical behaviour. Advances in understanding of cell wall ultrastructure and the control of cell growth present opportunities for modelling to clarify how growth–related mechanical properties arise from wall polymeric structure and biochemistry.
Modelling the control of interceptive actions
Authors: Beek P. J. , Dessing J. C. , Peper C. E. , Bullock D.
Published: September 2003

In recent years, several phenomenological dynamical models have been formulated that describe how perceptual variables are incorporated in the control of motor variables. We call these short–route models as they do not address how perception–action patterns might be constrained by the dynamical properties of the sensory, neural and musculoskeletal subsystems of the human action system. As an alternative, we advocate a long–route modelling approach in which the dynamics of these subsystems are explicitly addressed and integrated to reproduce interceptive actions. The approach is exemplified through a discussion of a recently developed model for interceptive actions consisting of a neural network architecture for the online generation of motor outflow commands, based on time–to–contact information and information about the relative positions and velocities of hand and ball. This network is shown to be consistent with both behavioural and neurophysiological data. Finally, some problems are discussed with regard to the question of how the motor outflow commands (i.e. the intended movement) might be modulated in view of the musculoskeletal dynamics.
The ARG1-LIKE2 Gene of Arabidopsis Functions in a Gravity Signal Transduction Pathway That Is Genetically Distinct from the PGM Pathway
Authors: Guan Changhui , Rosen Elizabeth S. , Boonsirichai Kanokporn , Poff Kenneth L. , Masson Patrick H.
Published: September 2003

The arl2 mutants of Arabidopsis display altered root and hypocotyl gravitropism, whereas their inflorescence stems are fully gravitropic. Interestingly, mutant roots respond like the wild type to phytohormones and an inhibitor of polar auxin transport. Also, their cap columella cells accumulate starch similarly to wild-type cells, and mutant hypocotyls display strong phototropic responses to lateral light stimulation. The ARL2 gene encodes a DnaJ-like protein similar to ARG1, another protein previously implicated in gravity signal transduction in Arabidopsis seedlings. ARL2 is expressed at low levels in all organs of seedlings and plants. arl2-1 arg1-2 double mutant roots display kinetics of gravitropism similar to those of single mutants. However, double mutants carrying both arl2-1 and pgm-1 (a mutation in the starch-biosynthetic gene PHOSPHOGLUCOMUTASE) at the homozygous state display a more pronounced root gravitropic defect than the single mutants. On the other hand, seedlings with a null mutation in ARL1, a paralog of ARG1 and ARL2, behave similarly to the wild type in gravitropism and other related assays. Taken together, the results suggest that ARG1 and ARL2 function in the same gravity signal transduction pathway in the hypocotyl and root of Arabidopsis seedlings, distinct from the pathway involving PGM.
Factors affecting adoption of electronic commerce technologies by SMEs: an Australian study
Authors: Lawson Robyn , Alcock Carole , Cooper Joan , Burgess Lois
Published: September 2003

Using the Internet for electronic business has become an area of action for the Australian government. This paper presents research results from two regional areas, which indicate that while most manufacturing SMEs use e‐mail, very few are involved in electronic commerce activities. Major barriers are concern about security and privacy of transactions, cost of consultants, and lack of IT expertise of staff. Employing people with appropriate knowledge has been added to current training methods such as on‐the‐job training. Results from the two regional areas are found to be consistent. Comparisons between small and medium organisations highlight some differences.
SME e‐business and supplier‐customer relations
Authors: Stone Merlin
Published: September 2003

This article starts with definitions of e‐business and a summary of what it means for businesses. This is followed by a quick description of a model of e‐business adoption. It then argues that modelling has reached a secure enough state for us to be able to predict benefits of adoption with some certainty and to determine a cost‐effective way forward for most smaller businesses. It then reviews briefly some evidence about adoption and interprets this in the light of the previous arguments. This article is very definitely an opinion article. It is not based on a comprehensive research programme. Rather, it is based on an interpretation of the masses of private and confidential evidence that flow in the veins of IBM, to which the author has access. It is skewed towards how e‐business affects the relationships between companies and their customers.
The Development of Argument Skills
Authors: Kuhn Deanna , Udell Wadiya
Published: September 2003

This work sought to obtain experimental evidence to corroborate cross‐sectional patterns of development in argument skills and to evaluate the effectiveness of an intervention designed to foster development of these skills in academically at‐risk 13‐ to 14‐year‐olds. Students participated in 16 sessions of a collaborative, goal‐based activity providing dense exercise of argumentive thinking. One condition included peer dialogues; another did not. The former was the more effective, although both groups progressed. Participants showed increased frequency of usage of powerful argumentive discourse strategies, such as counterargument, and decreased frequency of less effective strategies. Quality of individual arguments (for or against a claim) also improved, supporting the existence of a close relation between these two kinds of argument skills.
Do Young Children Always Say Yes to Yes–No Questions? A Metadevelopmental Study of the Affirmation Bias
Authors: Heather Fritzley V. , Lee Kang
Published: September 2003

The present study investigated whether yes–no questions would lead to a yes bias in young children. Four experiments were conducted in which 2‐ to 5‐year‐olds were asked comprehensible and incomprehensible yes–no questions concerning familiar and unfamiliar objects. Consistent findings were obtained: (a) 2‐year‐olds displayed a consistent yes bias; (b) 4‐ and 5‐year‐olds exhibited no response bias toward comprehensible questions and a nay‐saying bias toward incomprehensible questions; and (c) 3‐year‐olds' results were mixed, suggesting that the age of 3 years is a period of developmental transition in response tendency toward yes–no questions. The findings suggest that yes–no questions are suitable for older children, providing they are comprehensible, but may result in biased results when used with younger children and when incomprehensible.
Prosocial Development in Relation to Children's and Mothers' Psychological Problems
Authors: Hay Dale F. , Pawlby Susan
Published: September 2003

The study tested whether children's prosocial behavior was negatively or positively related to children's and mothers' psychological problems. Participants were 149 London families when mothers were pregnant and followed up in infancy and at ages 4 and 11. Children's cooperation at 4 and general prosocial tendencies at 11 were negatively associated with externalizing problems but unrelated to internalizing problems. A subgroup of children who were more prosocial than average expressed clinically significant worries about family members. Maternal depression decreased prosocial behavior in the eyes of adults, but children of depressed mothers saw themselves to be prosocial. Early cooperation protected children against later risk for externalizing problems, even when their early behavioral problems were taken into account.
Testing the Dynamic Field Theory: Working Memory for Locations Becomes More Spatially Precise Over Development
Authors: Schutte Anne R. , Spencer John P. , Schöner Gregor
Published: September 2003

The dynamic field theory predicts that biases toward remembered locations depend on the separation between targets, and the spatial precision of interactions in working memory that become enhanced over development. This was tested by varying the separation between A and B locations in a sandbox. Children searched for an object 6 times at an A location, followed by 3 trials at a B location. Two‐ and 4‐year‐olds', but not 6‐year‐olds', responses were biased toward A when A and B were 9‐in. and 6‐in. apart. When A and B were separated by 2 in., however, 4‐ and 6‐year‐olds' responses were biased toward A. Thus, the separation at which responses were biased toward A decreased across age groups, supporting the predictions of the theory.
The Role of Mental Health Factors and Program Engagement in the Effectiveness of a Preventive Parenting Program for Head Start Mothers
Authors: Baydar Nazli , Reid M. Jamila , Webster‐Stratton Carolyn
Published: September 2003

Head Start centers were randomly assigned to intervention (parent training) or control conditions, and the role of maternal mental health risk factors on participation in and benefit from parent training was examined. Parenting was measured by parent report and independent observation in 3 domains: harsh/negative, supportive/positive, inconsistent/ineffective parenting. Structural equation modeling showed that parent engagement training was associated with improved parenting in a dose‐response fashion. Mothers with mental health risk factors (i.e., depression, anger, history of abuse as a child, and substance abuse) exhibited poorer parenting than mothers without these risk factors. However, mothers with risk factors were engaged in and benefited from the parenting training program at levels that were comparable to mothers without these risk factors.
Correlation of Quantitative Risk Results for High Hazard Processes
Authors: Wang Yanjun , West Harry H. , Teague Tom L. , Hasan Najmul , Mannan M. Sam
Published: September 2003

A quantitative risk analysis was conducted to evaluate the design of the VX neutralization subsystem and related support facilities of the U.S. Army Newport Chemical Agent Disposal Facility. Three major incidents including agent release, personnel injury, and system loss were studied using fault tree analysis methodology. Each incident was assigned a risk assessment code based on the severity level and probability of occurrence of the incident. Safety mitigations or design changes were recommended to bring the “undesired” risk level (typical agent release events) to be “acceptable with controls” or “acceptable.”
Application of Geostatistics to Risk Assessment
Authors: Thayer William C. , Griffith Daniel A. , Goodrum Philip E. , Diamond Gary L. , Hassett James M.
Published: September 2003

Geostatistics offers two fundamental contributions to environmental contaminant exposure assessment: (1) a group of methods to quantitatively describe the spatial distribution of a pollutant and (2) the ability to improve estimates of the exposure point concentration by exploiting the geospatial information present in the data. The second contribution is particularly valuable when exposure estimates must be derived from small data sets, which is often the case in environmental risk assessment. This article addresses two topics related to the use of geostatistics in human and ecological risk assessments performed at hazardous waste sites: (1) the importance of assessing model assumptions when using geostatistics and (2) the use of geostatistics to improve estimates of the exposure point concentration (EPC) in the limited data scenario. The latter topic is approached here by comparing design‐based estimators that are familiar to environmental risk assessors (e.g., Land's method) with geostatistics, a model‐based estimator. In this report, we summarize the basics of spatial weighting of sample data, kriging, and geostatistical simulation. We then explore the two topics identified above in a case study, using soil lead concentration data from a Superfund site (a skeet and trap range). We also describe several areas where research is needed to advance the use of geostatistics in environmental risk assessment.
Microstructural evolution during film growth
Authors: Petrov I. , Barna P. B. , Hultman L. , Greene J. E.
Published: September 2003

Atomic-scale control and manipulation of the microstructure of polycrystalline thin films during kinetically limited low-temperature deposition, crucial for a broad range of industrial applications, has been a leading goal of materials science during the past decades. Here, we review the present understanding of film growth processes—nucleation, coalescence, competitive grain growth, and recrystallization—and their role in microstructural evolution as a function of deposition variables including temperature, the presence of reactive species, and the use of low-energy ion irradiation during growth.
Composition control and dielectric properties of bismuth zinc niobate thin films synthesized by radio-frequency magnetron sputtering
Authors: Lu Jiwei , Chen Zhiqiang , Taylor Troy R. , Stemmer Susanne
Published: September 2003

Radio-frequency sputtering was used to deposit near-stoichiometric Bi1.5Zn1.0Nb1.5O7 (BZN) films. Composition, crystallinity, and phase purity of the films were investigated by Rutherford backscattering spectrometry, x-ray diffraction, and transmission electron microscopy (TEM). X-ray diffraction detected cubic pyrochlore in films that were annealed above 400 °C. Films were fully crystallized at 750 °C. TEM and electron diffraction confirmed the cubic pyrochlore structure of the grains. Dielectric constant and loss were measured using planar Si/SiO2/Pt/BZN/Pt and Al2O3/Pt/BZN/Pt capacitor structures, respectively. After annealing at 750 °C, films on Pt coated silicon wafers showed a permittivity of 170, low dielectric losses, and a large electric field tunability of the dielectric constant at a measurement frequency of 1 MHz. Dielectric loss tangents improved when substrates were moderately heated during deposition.
How metals bind: The deformable-jellium model with correlated electrons
Authors: Tran Hoang T. , Perdew John P.
Published: September 2003

Atoms cohere to form solids largely due to exchange and correlation. The volume is set by a balance between the expansive electronic kinetic energy and the compressive exchange-correlation energy. These effects are simply illustrated by the jellium model, in which the valence electrons neutralize a positive background charge that is rigidly uniform. But the formation of free atoms under extreme expansion is found only in the deformable-jellium model. Deformable jellium is condensed matter in miniature, displaying not only bulk cohesion with a realistic equation of state and surface effects, but also phonons and plasmons and their soft mode instabilities. By drawing an analogy with the motion of shoppers in a mall, we also discuss an intuitive picture of exchange and correlation (the tendency of electrons not to bump into other electrons or into themselves).
Toxins-Antitoxins: Plasmid Maintenance, Programmed Cell Death, and Cell Cycle Arrest
Authors: Hayes Finbarr
Published: September 2003

Antibiotic resistance, virulence, and other plasmids in bacteria use toxin-antitoxin gene pairs to ensure their persistence during host replication. The toxin-antitoxin system eliminates plasmid-free cells that emerge as a result of segregation or replication defects and contributes to intra- and interspecies plasmid dissemination. Chromosomal homologs of toxin-antitoxin genes are widely distributed in pathogenic and other bacteria and induce reversible cell cycle arrest or programmed cell death in response to starvation or other adverse conditions. The dissection of the interaction of the toxins with intracellular targets and the elucidation of the tertiary structures of toxin-antitoxin complexes have provided exciting insights into toxin-antitoxin behavior.
Which Future for Humanity?
Authors: Pielke Roger A.
Published: September 2003

Our Final Hour
A Scientist's Warning; How Terror, Error, and Environmental Disaster Threaten Humankind's Future in This Century--On Earth and Beyond. by Martin Rees. Basic Books (Perseus), New York, 2003. 238 pp. $25, C$39. ISBN 0-465-06862-6.

Our Final Century
The 50/50 Threat to Humanity's Survival. by Martin Rees. William Heinemann, London, 2003. 238 pp. £17.99. ISBN 0-434-00809-5.

Exploring reasons why the prospects for human survival on Earth may be dire, Rees provides a calm consideration of apocalyptic scenarios that science and technology have made possible.
Drinking and Its Burden in a Global Perspective: Policy Considerations and Options
Authors: Room Robin , Graham Kathryn , Rehm Jürgen , Jernigan David , Monteiro Maristela
Published: September 2003

Aims: To identify the policy implications of the magnitude and characteristics of alcohol consumption and problems, viewed globally, and to summarize conclusions on the effectiveness of the strategies available to policymakers concerned with reducing rates of alcohol problems. Design/Methods/Setting: This summative article draws on the findings of the articles preceding it and of reviews of the literature. Findings and Conclusions: Overall volume of consumption is the major factor in the prevalence of harms from drinking. Since consumption and associated problems tend to increase with economic development, policymakers in developing economies should be especially aware of the need to develop policies to minimize overall increases in alcohol consumption. Unrecorded consumption is also an important consideration for policy in many parts of the world, and poses difficulties for alcohol control policies. Drinking pattern is also an important contributing factor toward alcohol-related harm. Although some drinking patterns have been shown to produce beneficial health effects, because the net effect of alcohol on coronary disease is negative in most parts of the world, policies that promote abstinence or lower drinking overall may be the safest options. Moreover, sporadic intoxication is common in many parts of the world, and policies are unlikely to change this drinking pattern at least in the short to medium term. At the same time, because injuries comprise a large proportion of the burden of alcohol, it is appropriate to enhance these policies with targeted harm reduction strategies such as drinking and driving countermeasures and interventions focused on reducing alcohol-related violence in specific high-risk settings. Alcohol consumption is a major factor for the global burden of disease and should be considered a public health priority globally, regionally, and nationally for the vast majority of countries in the world. The need for alcohol policy is even stronger when it is taken into consideration that the burden of alcohol estimated in the WHO Global Burden of Disease project includes primarily health problems related to drinking. From the limited evidence available, however, social problems related to drinking seem to impose at least as much burden. Moreover, the burden for both social and health harms fall not only on the drinker, but also on others. There is a broad literature on policy interventions to reduce alcohol problems. Effective strategies include controls over distribution and sale, taxation, drinking-driving countermeasures, brief interventions by health workers or counselors, and selected harm reduction measures. There is a need to develop the growing literature on comparative evaluations of cost-effectiveness of such strategies. In addition, international agreements are needed to support the effectiveness of national strategies.
The Discriminant Validity of Alcohol Use Disorder in Well-Functioning Men with Hazardous Alcohol Use
Authors: de Bruijn H. , Korzec A. , Arndt T. , van den Brink W.
Published: September 2003

The purpose of this study was to establish the discriminant validity of alcohol use disorder (AUD) diagnoses within a population of well-functioning male heavy drinkers. A group of 57 subjects with a consumption of at least 28 alcoholic units (AU)/week was recruited from wine-tasting clubs. Within this group, a comparison was made between those individuals who met the criteria of AUD and those who did not. We compared the subjective and objective health status and drinking habits of both groups. No significant differences were found between the individuals with AUD and those without AUD, or between individuals with alcohol dependence and those without AUD, except for their drinking pattern. These findings raise doubt of the discriminant validity of AUD diagnoses in well-educated heavy wine drinkers.
Highly Efficient Gene Transduction into the Brain Using High-Titer Retroviral Vectors
Authors: Nanmoku Koji , Kawano Masako , Iwasaki Yasuno , Ikenaka Kazuhiro
Published: September 2003

Moloney murine leukemia retroviral vectors are more suitable as tools for gene delivery in vivo in comparison to other vectors due to their stable expression and absence of cytotoxicity. However, because of their low titers and poor proliferation rate in the adult nervous system, the application of retroviral vectors to the nervous system has been limited. To overcome this disadvantage, we have attempted to achieve higher viral titers and apply them to the embryonic mouse brain. By utilizing our improved packaging cell line and concentrating the viral supernatant by the low-speed centrifugation method, we have successfully increased the retroviral titer up to 1012 cfu/ml. This titer is over 106-fold greater than routinely achieved retroviral titers, and is comparable to, or even higher than, those of adenoviral vectors. We investigated the efficacy of gene transfer into the nervous system, which has thus far proven quite recalcitrant to genetic transfer by characteristically low retroviral titers. Using our retroviral preparation, we have demonstrated the highly efficient delivery and long-term expression of a foreign gene into neural cells both in vitro and in vivo. Moreover, we demonstrated that predominant gene delivery into the neurons of one cortical layer can be achieved by choosing an appropriate date of retroviral infection.
Distinguishing Features of Progenitor Cells in the Late Embryonic and Adult Hippocampus
Authors: Limke Tobi L. , Cai Jingli , Miura Takumi , Rao Mahendra S. , Mattson Mark P.
Published: September 2003

Adult neurogenesis occurs within the subgranular layer of the hippocampal dentate gyrus. In this study, we examined dividing cells in the late embryonic and adult rat hippocampus to identify distinguishing characteristics and potential neural stem cell population(s), as identified by the putative neural stem cell markers FGFR4 and Sox1. In embryonic hippocampal cells in primary culture, basic fibroblast factor caused cell proliferation, increased telomerase activity and upregulation of FGFR4 mRNA. In both the embryonic and adult brains, proliferating cells express Sox1, as well as markers for neuronal- and glial-restricted precursors. However, the cell markers associated with cells expressing proliferative cell nuclear antigen (PCNA) and Sox1 differed between late embryonic and adult hippocampus, suggesting that there are important differences between adult and embryonic neurogenesis.
Percutaneous Fixation of Comminuted Fractures of the Femur and Tibia
Authors: Pospula Wieslaw , Abu Al Noor Tarek , Ezzat Farid , Abdul Malak Farid
Published: September 2003

Objective: To present initial experience of treating patients with comminuted fractures of the diaphyseal and metaphyseal areas of the femur and tibia. Subjects and Methods: Sixteen patients were involved in the study. All the16 patients (11 males and 5 females, average age 34 years) with closed, comminuted fractures of femur (n = 9) and tibia (n = 7) were operated on using the principle of minimal access surgery and biological fixation that maximally preserved the soft tissues and fracture hematoma. Results: All the fractures united, operated limbs had good function, and no complications occurred. Conclusion: Our findings indicate that minimal access surgery is a useful fixation method in the treatment of comminuted diaphyseal and metaphyseal fractures of the femur and tibia.
Risk Factors, Subtypes and Outcome of Ischaemic Stroke in Kuwait – A Hospital-Based Study
Authors: Al-Shammri S. , Shahid Z. , Ghali A. , Mehndiratta M.M. , Swaminathan T.R. , Chadha G. , Sharma P.N. , Akanji A.O.
Published: September 2003

Objective: To report on stroke subtypes, associated risk factors and outcome in Kuwait. Methods: The records of 62 patients (30 male, 32 female) admitted with diagnosis of stroke to Kuwait Oil Company Hospital, Kuwait, a tertiary care hospital, during a 5-year period (1995–1999), were retrospectively reviewed. Results: Small artery infarction was the most common subtype and occurred in 37 subjects (59.7%); less common were atherosclerotic large artery strokes (19 patients, 30.6%) and strokes of cardio-embolic origin (6 patients, 9.7%). Identifiable risk factors or associated morbidities were hypertension (72.5%), diabetes mellitus (69.4%), ischaemic heart disease (14.5%), history of migraine (8.1%), lone atrial fibrillation (5.0%), and valvular heart disease (1.6%). The most important determinants of a deleterious 30-day outcome, as indicated by severe disability or death, were female gender, lack of use of anti-platelet drugs, presence of a large artery infarction stroke subtype, and cardio-embolic stroke. Conclusion: Prevalence of hypertension and diabetes is high among patients with stroke in Kuwait, with rates higher than those found in any previous reports from the Gulf region. Two unusual observations were that women had a rather high frequency of stroke, and infarction of the small artery was more common than that of the large artery. Outcome, as indicated by severe disability or death, was worse among women, elderly patients, and those with large artery atherosclerotic and cardio-embolic strokes. There is some evidence that such a deleterious outcome might be ameliorated with use of anti-platelet drugs.
Antimicrobial Susceptibility, Phage Typing and Plasmid Profile of Salmonella enterica Serotype paratyphi A Strains Isolated in Kuwait
Authors: Panigrahi D. , Chugh T.D. , West P.W.J. , Dimitrov T.Z. , Groover S. , Mehta G.
Published: September 2003

Objective: To determine the antimicrobial susceptibility, phage type and plasmid profile pattern of Salmonella enterica serotype paratyphi A strains isolated in Kuwait. Material and Methods: From January 1995 to December 1999, 106 strains of S. enterica serotype paratyphi A isolated from an equal number of cases of enteric fever, attending the Infectious Disease and Mubarak Al-Kabeer Hospitals in Kuwait were investigated. The isolates were tested for antimicrobial susceptibility to 8 commonly used antimicrobial agents. Their phage type and plasmid profile patterns were determined using an international set of phages and Qiagen plasmid mini kit, respectively. Results: All of the isolates were susceptible to ciprofloxacin, cefuroxime, ceftazidime, piperacillin and co-trimoxazole. One hundred isolates were susceptible to ampicillin, 99 to chloramphenicol and 98 to tetracycline. None of the isolates was multidrug resistant. Sixty-six percent of the isolates were phage type I, 27.4% phage type II and 6.6% were untypable. All phage type I and untypable strains had 3 plasmids of 2.2, 5 and 20 kb, whereas phage type II strains had only 1 plasmid of 20 kb. Conclusion: The findings indicate that while all of the isolates of the S. enterica serotype paratyphi A were susceptible to 4 of the drugs tested, some were resistant to ampicillin, chloramphenicol or tetracycline, thereby indicating the need for continued surveillance and monitoring of antimicrobial susceptibility of these isolates.
A Molecular Look at the Glomerular Barrier
Authors: Miner Jeffrey H.
Published: September 2003

The glomerular barrier is the kidney’s physical block to the unrestricted flow of molecules from the plasma into the urinary space. Its exquisite selectivity allows solutes and water in the glomerular capillaries to pass through, but it prevents the bulk of plasma proteins, most notably albumin, from crossing. Classically, the barrier consists of three distinct components: glomerular endothelium, glomerular basement membrane, and glomerular epithelium (podocytes). In this review, I discuss these three components, with particular emphasis on the barrier presumed to be imparted by a specialized podocyte cell–cell junction, the glomerular slit diaphragm.
TGF-β1 Induces Aberrant Laminin Chain and Collagen Type IV Isotype Expression in the Glomerular Basement Membrane
Authors: Chai Qing , Krag Søren , Miner Jeffrey H. , Randel Nyengaard Jens , Chai Song , Wogensen Lise
Published: September 2003

Transforming growth factor-β1 (TGF-β1) contributes to the thickening of the glomerular basement membrane (GBM), abnormal deposition of extracellular matrix (ECM) therein and expansion of the mesangial matrix (MM) in several glomerular kidney diseases. However, the influence of TGF-β1 on the expression of collagen IV isotypes and laminin chains in the GBM and the MM in vivo is not known in detail. By using transgenic mice with TGF-β1 expression targeted to the juxtaglomerular apparatus and a combination of immunohistochemistry, Western blotting, immunoelectron microscopy and in situ hybridization, we investigated the contribution of different laminin chains and collagen type IV isotypes to the basement membrane thickening and mesangial expansion. We report that exposure of the glomerulus to TGF-β1 in vivo induces aberrant deposition of fetal laminin α1, α2 and β1 chains and collagen type IVα1/α2 in the GBM. On the other hand, the TGF-β1-mediated expansion of the mesangial ECM is dominated by the normal components. We found that the cellular origin of at least laminin α1 and α2 chains may be the glomerular endothelial cells. We speculate that the endothelial cells could contribute to TGF-β1-induced glomerulopathy and should be considered as target cells for early intervention in glomerular diseases associated with TGF-β1 in man.
Total Right Ventricular Exclusion Improves Left Ventricular Function in Patients With End-Stage Congestive Right Ventricular Failure
Authors: Takagaki Masami , Ishino Kozo , Kawada Masaaki , Ohtsuki Shin-ichi , Hirota Masanori , Tedoriya Takeo , Tanabe Yasuharu , Nakai Mikizo , Sano Shunji
Published: September 2003

Background—

We developed a total right ventricular (RV) exclusion procedure for the treatment of isolated congestive RV failure. The objective of the present study was to elucidate the effects of a complete removal of RV volume overload (RVVO) on the surgically created single left ventricle (LV).

Methods and Results—

Three adults (2 arrhythmogenic RV dysplasia, 1 Ebstein) and 5 children (all Ebstein) in NYHA class IV underwent the procedure. The RV free wall was resected from the heart, and the tricuspid orifice was closed. Pulmonary blood supply was obtained by a cavopulmonary connection in 6 patients and a systemic-pulmonary shunt in 2. The LV function was evaluated by 2-dimensional echocardiography 1 month after the surgery. All patients are alive. The paradoxical movement of the interventricular septum and geometry of the LV expressed by its eccentricity (2.1 to 1.2,
P
<0.01) were normalized after the operation in all 8 patients. LV end-diastolic volumes (59% to 109% of normal value,
P
<0.01), indexed maximal left atrial area (6.5 to 10.5 cm
2
/m
2
,
P
<0.01), LV ejection fraction (27% to 62%,
P
<0.01), and cardiac index (2.1 to 3.3 L/min/m
2
,
P
<0.05) all significantly increased.

Conclusion—

Removal of the RVVO by means of the total RV exclusion procedure provides effective volume loading, restores a cylindrical shape, and improves contractile function of the LV, thus leading to increased systemic output.
Stability of Ascending Aortic Dilatation Following Aortic Valve Replacement
Authors: Andrus Bruce W. , O’Rourke Daniel J. , Dacey Lawrence J. , Palac Robert T.
Published: September 2003

Background—

Replacement of the ascending aorta (Asc Ao) at the time of aortic valve replacement (AVR) is controversial because the risk of progressive dilatation following valve replacement is uncertain. Our aim was to determine the natural history of ascending aortic dilatation following AVR.

Methods and Results—

We studied 185 patients undergoing AVR at our institution between 1992 and 1999. Clinical and echocardiographic data were obtained by merging our institutional echocardiographic database with the DHMC component of the Northern New England Cardiovascular Disease Study Group database. Baseline Asc Ao measurements obtained from intraoperative transesophageal echocardiograms or early (<8 weeks) postoperative transthoracic echocardiograms were compared with late follow-up measurements (mean follow-up 30.0±23.4 months). During follow-up, there was no increase in the mean Asc Ao diameter (3.6±0.6 cm versus 3.6±0.6 cm, p=NS). Progressive aortic dilatation, defined as an increase in diameter >0.3 cm, occurred in 27/185 patients (15%). Baseline Asc Ao dilatation (≥3.5 cm) was present in 107/185 patients (58%). In this subset of patients, there was no increase in mean Asc Ao diameter (4.0±0.4 versus 3.9±0.6 cm, p=NS) and progressive aortic dilatation occurred in only 10 patients (9.3%). No patients with baseline aortic dilatation (range, 3.5 to 5.3 cm) dilated beyond 5.5 cm on follow-up (range, 2.4 to 5.5 cm). There were no clinical or valvular characteristics that predicted progressive Asc Ao dilatation.

Conclusions—

An increase in Asc Ao dilatation occurs infrequently following AVR and therefore, argues against routine Asc Ao replacement at the time of AVR.
Prognosis of Retrograde Dissection From the Descending to the Ascending Aorta
Authors: Kaji Shuichiro , Akasaka Takashi , Katayama Minako , Yamamuro Atsushi , Yamabe Kenji , Tamita Koichi , Akiyama Maki , Watanabe Nozomi , Tanemoto Kazuo , Morioka Shigefumi , Yoshida Kiyoshi
Published: September 2003

Background—

Natural history of aortic dissection (AD) with intimal tear in the descending or abdominal aorta and retrograde extension into the ascending aorta (retrograde AD) remains unknown. The purpose of this study was to elucidate medium-term prognosis of patients with retrograde AD.

Methods and Results—

Study population consisted of 109 patients with acute type A AD. There were 27 patients (25%) with retrograde AD and 82 patients (75%) with intimal tear in the ascending aorta (antegrade AD). In antegrade AD patients, 60 patients underwent surgery and 22 patients were treated medically. In retrograde AD patients, 14 patients showed localized crescentic high attenuation area along the ascending aortic wall without enhancement in computed tomography. Transesophageal echocardiography revealed complete thrombosis of false lumen (FL) in the ascending aorta (retrograde thrombosed). The remaining 13 patients showed incomplete or no thrombosis (retrograde nonthrombosed). All retrograde nonthrombosed AD patients underwent surgery except for 1 patient with stroke, whereas all retrograde thrombosed AD patients were treated medically. In-hospital mortality rate of retrograde AD patients was significantly lower than that of antegrade AD patients (15% versus 38%,
P
=0.027). The survival rates in retrograde AD patients were all 85% at 1, 2, and 5 years, which were significantly higher than those of antegrade AD patients (63%, 62%, and 57%, respectively)(
P
=0.009).

Conclusions—

Patients with type A retrograde AD have better medium-term prognosis than patients with antegrade AD. Retrograde AD patients with thrombosed FL in the ascending aorta could be treated medically with timed surgical repair.