bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal dusting of ferritic Fe‐Al‐M‐C (M = Ti, V, Nb, Ta) alloys in CO‐H2‐H2O gas mixtures at 650 °C
Authors: Schneider A. , Zhang J.
Published: October 2003

Iron aluminides are known for their resistance to high temperature oxidation and sulphidation. Only little information is available about carburisation and metal dusting of Fe‐Al alloys. Metal dusting experiments with Fe‐15Al and Fe‐15Al‐2M‐1C alloys (in at.%) with M = Ti, V, Nb, or Ta were conducted at 650°C in CO‐H2‐H2O gas mixtures with the carbon activity ac = 28. The kinetics of the carbon transfer was measured using thermogravimetric analysis (TGA). It is shown that the mass gain kinetics decreases by adding the alloying elements Nb, Ta, V, or Ti with C. Alloying with titanium and carbon leads to the most significant decreasing effect. The metallographic cross section observation showed a general metal wastage for Fe‐15Al, but local pitting for the Fe‐15Al‐2Nb‐1C and Fe‐15Al‐2Ta‐1C alloys. For the Fe‐15Al‐2V‐1C and Fe‐15Al‐2Ti‐1C alloys no significant attack was observed. Needle‐ or plate‐like Fe3AlCx precipitates were detected in the carburised samples. The existence of this ternary carbide with perovskite structure was predicted by thermodynamic calculations using the software Thermo‐Calc. The morphology of graphite on the surface was analysed by scanning electron microscopy (SEM). Mainly fine filaments with iron containing particles were detected. Cementite was detected in the coke layer by X‐ray diffraction analysis (XRD).
Synthesis of Conjugated Carbazole Trimers and Pentamers by Suzuki Coupling
Authors: Paliulis Osvaldas , Ostrauskaite Jolita , Gaidelis Valentas , Jankauskas Vygintas , Strohriegl Peter
Published: October 2003

A series of N‐alkylcarbazol‐3,6‐diyl trimers and pentamers has been synthesized by stepwise Suzuki coupling. The trimers with isopropyl and longer alkyl substituents at the nitrogen atom and all the pentamers form stable glasses with glass transition temperatures varying from 30 to 148 °C for the trimers and 65 to 104 °C for the pentamers. The ionization potential of the N‐alkylcarbazol‐3,6‐diyl trimers is 5.25 eV and 5.20 eV for the pentamers. N‐alkylcarbazol‐3,6‐diyl compounds typically exhibit hole‐drift mobilities in the range of 10−4–10−6 cm2 · V−1 · s−1. The highest hole‐drift mobility observed in an amorphous film of N‐octylcarbazol‐3,6‐diyl pentamer reached 10−3 cm2 · V−1 · s−1 at an applied electric field of 8.1 × 105 V · cm−1.

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Analysis of Crosslinked Styrene‐Butadiene Rubbers by Liquid Chromatography and FT‐IR Spectroscopy, 1
Authors: Pasch Harald , Siewing Anja , Heinz Lars‐Christian
Published: October 2003

Crosslinked styrene‐butadiene and butadiene rubbers can efficiently be analyzed by liquid chromatography and FT‐IR spectroscopy. In a first step the vulcanizate is pyrolyzed under mild conditions. The resulting high molar mass fragments are extracted from the bulk material and analyzed by size exclusion chromatography. The molar masses of the extractables are in the range of 3 000 to 25 000 g/mol. The chemical composition as a function of molar mass is visualized by coupled SEC‐FT‐IR spectroscopy. By quantitative analysis of the FT‐IR spectra the concentrations of the different structural units, including styrene, 1,4‐trans‐butadiene, 1,2‐vinylbutadiene, and 1,4‐cis‐butadiene, are determined. It is shown that the chemical composition of the original non‐crosslinked rubbers and the chemical composition of the extractables are rather identical. Therefore, this technique can be used to obtain structural information on rubber formulations even in the case when the material is already vulcanized.

SEC chromatograms of SBR 1712 and the extractables after pyrolysis, stationary phase: SDV linear, mobile phase: THF, detector: ELSD.

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SEC chromatograms of SBR 1712 and the extractables after pyrolysis, stationary phase: SDV linear, mobile phase: THF, detector: ELSD.
Dynamic Mechanical and Thermal Properties of Modified Poly(propylene) Wood Fiber Composites
Authors: Hristov Velichko , Vasileva Stefanka
Published: October 2003

Dynamic mechanical and thermal properties of poly(propylene) (PP)/wood fiber composites have been studied using Dynamic Mechanical Analysis (DMA). In order to modify the PP matrix maleated poly(propylene) (PPMA) and poly(butadiene‐styrene) rubber were used as compatibilizer and impact modifier, respectively. tan δ peak temperature of the compatibilized systems was found to increase in comparison to that of composites without coupling agent, indicating improved adhesion and interaction between PP matrix and wood fibers. The storage modulus (E′)‐temperature (T) relationship of all composites is characterized by two transition points. The E′ of compatibilized composites exhibits higher values than those of the uncompatibilized ones at low temperatures (up to the β‐relaxation). In the temperature interval from β‐transition to 60 °C, the composites containing PPMA have lower modulus, and above 60 °C the E′‐T curves tend to converge. DSC indicates that the wood fibers act as nucleating agent for PP. Maleated poly(propylene) slightly retards the crystallization rate, resulting in a composite structure, composed mainly of large spherulites, with a higher crystallinity index. Fourier Transform Infrared (FT‐IR) microscopy was also applied to explore the interface between wood fibers and PP matrix. The strong absorption band at 1 738 cm−1 in the IR spectrum scanned at the interfacial region between the fiber and matrix indicated that PPMA had probably reacted either by formation of ester bonds or hydrogen bonding with hydroxyl groups from cellulose.

Optical micrograph of PPWF composite in polarized light.

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Optical micrograph of PPWF composite in polarized light.
Biodegradations of block copolymers composed of L‐ or D,L‐lactide and six‐membered cyclic carbonates prepared with organolanthanide initiators
Authors: Tsutsumi Chikara , Yamamoto Katsuhiro , Ichimaru Akiko , Nodono Mitsufumi , Nakagawa Katsuhiko , Yasuda Hajime
Published: October 2003

Diblock copolymerizations of L‐ or D,L‐lactide (LA) with trimethylene carbonate (TMC) or 2,2‐dimethyltrimethylene carbonate (2,2‐DTMC) with SmMe(C5Me5)2‐(tetrahydrofuran) as an initiator and triblock copolymerizations of L‐ or D,L‐LA/cyclic carbonates/L‐ or D,L‐LA with [Sm(C5Me5)2]2(PhCCCCPh) as an initiator generated the desired block copolymers. This article describes the comparison of biodegradabilities by proteinase K and a compost and mechanical properties between the resulting di‐ or triblock copolymers and random copolymers composed of L‐ or D,L‐LA and cyclic carbonates. The scanning electron microscopic profiles of resulting polymers were measured to understand the morphological change during biodegradation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3572–3588, 2003
Amino alcohol additives for the fast living radical polymerization of methyl methacrylate with RuCl2(PPh3)3
Authors: Ando Tsuyoshi , Sawauchi Chie , Ouchi Makoto , Kamigaito Masami , Sawamoto Mitsuo
Published: October 2003

A series of amino alcohols [e.g., R2N(CH2)nOH (R = Me, Et, etc.; n = 2, 3, or 4)] were examined as additives for rate enhancement and finer reaction control in the living radical polymerization of methyl methacrylate with RuCl2(PPh3)3. In general, these additives were more effective in acceleration than the corresponding amines as well as mixtures of an amine and a nonsubstituted alcohol, diamines, or diols. For example, 2‐(diethylamino)ethanol significantly accelerated the polymerization (23 h, 91% at 60 °C) and gave polymers with narrower molecular weight distributions [weight‐average molecular weight/number‐average molecular weight (Mw/Mn) = 1.23], with respect to the system without the additive (550 h, 95%, Mw/Mn ∼ 2.0 at 80 °C; no polymerization at 60 °C). 1H NMR analysis showed the interaction between the amino alcohols and RuCl2(PPh3)3, which apparently formed a more active catalyst. Amino alcohols were also effective in Ru(Ind)Cl(PPh3)2‐catalyzed systems (96% in 8 h at 80 °C). High‐molecular‐weight poly(methyl methacrylate) (Mn ∼ 1.1 × 105) was synthesized with the RuCl2(PPh3)3/2‐(diethylamino)ethanol system, in which the polymerization reached 97% conversion in 4 h. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3597–3605, 2003
Reversible catenation of coordination rings with Pd(II) and/or Pt(II) metal centers: Chirality induction through catenation
Authors: Hori Akiko , Kataoka Hisashi , Akasaka Akihiko , Okano Takashi , Fujita Makoto
Published: October 2003

A Pd(II)‐linked coordination ring is reversibly transformed into its catenanted dimer at room temperature through the efficient organic stacking of the component rings. An analogous Pt(II)‐linked ring is also catenated only at high temperature (100 °C), but not at room temperature because of the kinetic inertness of Pt(II)‐ligand interaction. Interestingly, the combination of the Pd(II)‐ and the Pt(II)‐linked coordination rings selectively gives a Pd(II)/Pt(II) cross‐catenane, because the kinetically inert Pt(II) ring can be catenated only via the dissociation of the kinetically labile Pd(II) ring. Planer conformation of the monomer rings is twisted upon catenation, inducing helical chirality in the catenated structure. Thus, induced circular dichroism (ICD) is observed in the catenation when chiral‐1,2‐cyclohexandiamine is attached as a chiral auxiliary on the metal centers. The ICD decreases with increasing temperature due to less effective chiral aromatic stacking at higher temperature. The Pd(II) ring shows higher ICD than the Pt(II) ring, probably due to the more flexible conformation of the Pd(II) ring that can adopt chiral orientation easily. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3478–3485, 2003
Rod–coil block copolymers: An iterative synthetic approach via living free‐radical procedures
Authors: Gopalan Padma , Li Xuefa , Li Mingqi , Ober Christopher K. , Gonzales Chad P. , Hawker Craig J.
Published: October 2003

A modular approach has been developed for the synthesis of rod–coil block copolymers involving the initial preparation of a macroinitiator based on the rod block followed by the growth of the coil segment with living free‐radical procedures. The key feature of this strategy is the utilization of an alkoxyamine group from the beginning of the synthesis, which serves as a solubilizing group and ensures that each rod block contains a single initiating fragment. Using this approach permits block copolymers based on insoluble biphenyl ester oligomers to be conveniently prepared with coil segments that range from styrenes to acrylates to 1,3‐dienes. The tendency of the rod segments to crystallize is strongly dependent on the weight fraction of the rod segment and the chemical nature of the coil segment. Rod–coil molecules containing at least 25–35 wt % polystyrene or poly(n‐butyl acrylate) coil segments show a two‐dimensional hexagonal arrangement of rod aggregates, as characterized by transmission electron microscopy and small‐angle X‐ray scattering. Polyisoprene block copolymers exhibit a lamellar microstructure with short rigid domains in which the rod units lie in an interdigitated smectic C arrangement. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3640–3656, 2003
Nucleobase‐induced supramolecular polymerization in the solid state
Authors: Rowan Stuart J. , Suwanmala Phiriyatorn , Sivakova Sona
Published: October 2003

Supramolecular polymerization, that is, the self‐assembly of polymer‐like materials through the utilization of the noncovalent bond, has been a developing area of research over the last decade. In this article, we report the synthesis of nucleobase‐terminated (N6‐anisoyl‐adenine and thymine) low‐molecular‐weight poly(tetrahydrofuran) macromonomers (<2000 g mol−1). The adenine‐derived supramolecular telechelic polymer self‐assembled in the solid state to yield materials with film‐ and fiber‐forming capabilities. This material was thermally reversible and exhibited a ceiling temperature, above which a drop in viscosity was observed and fibers could no longer be obtained. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3589–3596, 2003
The contributions of Sam Greenhouse to research on psychiatric diagnosis and psychopharmacology
Authors: Katz Martin M. , Berman Nancy
Published: October 2003

Sam Greenhouse began his involvement in mental disorders research in 1954 when appointed chief of the Theoretical Statistics and Mathematics section at the National Institute of Mental Health. He remained with the NIMH until 1966. Despite moving on to several other positions at the NIH and at the university during the ensuing years, he continued as a consultant to NIMH investigators. He also participated actively as an advisor and co‐investigator on a number of important collaborative research programmes launched by the Institute in the 1970s and 1980s. His contributions to the design and methodology of the first clinical trials of drugs for the treatment of schizophrenia, to research aimed at revising the national and international classification systems for the mental disorders, and his participation in the planning of the first attempt to use the collaborative research model to test hypotheses about the genesis of a specific mental disorder (depression), are described. Finally, the signal importance of the ‘profile analysis of variance’ method that he and Seymour Geisser developed, to research on personality and mental disorders, is examined in detail. The authors describe applications of the method in their own research on the classification of the mental disorders, predicting response to drug treatment and the variations in the expression of mental illness across different cultures. Sam worked in mental health during an era of revolutionary changes in the diagnosis and treatment of mental disorders. The field was acutely aware of his many contributions to the progress of research and his colleagues are very grateful to have had the opportunity to work with him. Copyright © 2003 John Wiley & Sons, Ltd.
The analysis of profile data—revisited
Authors: Geisser Seymour
Published: October 2003

We revisit a former problem that led to much commentary regarding a proposed use of testing whether profiles for several groups in a repeated measurement scenario were parallel. Here we review previous approaches and propose Bayesian model selection to indicate whether the profiles can be considered parallel and if so support an estimation procedure for the profile differences. Copyright © 2003 John Wiley & Sons, Ltd.
Over‐ruling a group sequential boundary—a stopping rule versus a guideline
Authors: Lan K. K. Gordon , Lachin John M. , Bautista Oliver
Published: October 2003

We evaluate the properties of group sequential procedures where the trial is continued even though the boundary for statistical significance (stopping) to demonstrate effectiveness has been crossed. In this case, one may buy‐back the previously spent alpha probability to be re‐spent or re‐distributed at future looks. We show that such plans using an O'Brien–Fleming‐like spending function have a negligible effect on the final type I error probability and on the ultimate power of the study. With a Pocock‐like bound, however, there is a small additional loss in power. We also show that this approach can be simplified by using a fixed‐sample size Z critical value for future looks after buying‐back previously spent alpha, such as using a critical Z value of 1.96 for α=0.025. We show that this procedure preserves the type I error probability while incurring a minimal loss in power. In this sense, one still has a stopping boundary rather than simply a guideline. This concept is discussed relative to monitoring procedures for inferiority or futility, and cases where both an upper and lower boundary are employed. Copyright © 2003 John Wiley & Sons, Ltd.
Clinical trials, epidemiology, and public confidence
Authors: Seigel Daniel
Published: October 2003

Critics in the media have become wary of exaggerated research claims from clinical trials and epidemiological studies. Closer to home, reviews of published studies find a high frequency of poor quality in research methods, including those used for statistical analysis.

The statistical literature has long recognized that questionable research findings can occur when investigators fail to set aside their own outcome preferences as they analyse and interpret data. These preferences can be related to financial interests, a concern for patients, peer recognition, and commitment to a hypothesis. Several analyses of published papers provide evidence of an association between financial conflicts of interest and reported results.

If we are to regain professional and lay confidence in research findings some changes are required. Clinical journals need to develop more competence in the review of analytic methods and provide space for thorough discussion of published papers whose results are challenged. Graduate schools need to prepare students for the conflicting interests that surround the practice of statistics. Above all, each of us must recognize our responsibility to use analytic procedures that illuminate the research issues rather than those serving special interests. Copyright © 2003 John Wiley & Sons, Ltd.
Direct and vicarious victimization at school and at home as risk factors for suicidal cognition among Italian adolescents☆
Authors: Baldry Anna C. , Winkel Frans Willem
Published: October 2003

Suicidal cognition is defined here as the combination of thinking about committing suicide and engaging in self‐harm and is considered to indicate maladjustment following an extreme internalized reaction to negative life events. Victimization at home and at school might lead some youth to suicidal cognition. The present study aimed to examine cross‐sectional predictors of suicidal cognition focusing on the unique influence of ‘direct victimization’ at school by peers and at home by parents, over and above that of vicarious victimization (i.e. exposure to domestic violence). Participants were 998 adolescents randomly recruited from high schools in Italy who had to fill in a cross‐sectional survey measuring different dimensions associated with suicidal cognition.

Thoughts about committing suicide and self‐harming in the previous 6 months were reported by almost a fourth of the whole sample, with girls having these thoughts more frequently than boys. A high prevalence rate was reported also for direct victimization at school (over half of the sample), and at home (a third of the sample) and for vicarious victimization at home (reported by a fifth of the entire sample).

Multiple hierarchical regressions showed that a significant proportion of the total variance of suicidal cognition was explained by gender and age, meaning that older girls are more at risk of suicidal cognition than boys; relational victimization at school is also a risk factor. Direct victimization at home by the father for boys and by the father and the mother for girls significantly predicted suicidal cognition after controlling for exposure to domestic violence.
The code of the long-term biomass cycles in the Barents Sea
Authors: Yndestad Harald
Published: October 2003

Barents Sea capelin (Mallotus villosus), Norwegian spring-spawning herring (Cluea harengus), and Northeast Arctic cod (Gadus morhua) have been associated with large fluctuations of biomass growth. The cause of these large fluctuations has been poorly understood and led to problems in biomass management. The identification of a deterministic cause would provide the possibility of forecasting future biomass fluctuations. In this investigation, the Kola Section sea temperature and the biomasses of capelin, herring, and cod have been analyzed by a wavelet transform to identify the source of the long-term cycles. The wavelet analysis shows that the Kola Section temperature has dominant cycles at the lunar-nodal tide cycles of 3×18.6=55.8, 18.5 and 18.6/3 = 6.2 years. The recruitment of Barents Sea capelin, Norwegian spring-spawning herring, and Northeast Arctic cod has adopted an optimal recruitment cycle close to the stationary 6.2 years Kola temperature cycle. Long-term biomass growth is correlated to the phase relation between the biomass eigen-frequency cycle and the Kola temperature cycles. The biomasses of capelin, herring and cod have long-term growth when the 6.2 and 18.6 years Kola temperature cycles are positive at the same time. There is a long-term biomass reduction when the temperature cycles are not positive at the same time, and a biomass collapse when the temperature cycles are negative at the same time. The deterministic property of the 18.6 years lunar-nodal tide provides a new way of long-term biomass forecasting over periods of 50–80 years or more.
Observations and modeling of the tidal bottom boundary layer on the southern flank of Georges Bank
Authors: Werner Sandra R. , Beardsley Robert C. , Lentz Steven J. , Hebert David L. , Oakey Neil S.
Published: October 2003

We examine the vertical structure of the tidally driven bottom boundary layer during nearly homogeneous (N2 < 10−5 s−2) and strongly stratified (N2 ∼ 10−4 s−2) conditions in a shallow coastal region dominated by semidiurnal tides. From moored array and shipboard measurements taken at a 76‐m‐deep study site on the southern flank of Georges Bank, we infer tidal velocity profiles, bottom stress estimates, Richardson numbers, and turbulent dissipation rates. On the basis of our measurements, we discuss changes in tidal boundary‐layer dynamics in the presence of weak and strong stratification. We compare observations to results from two different one‐dimensional numerical circulation models: a two‐layer eddy viscosity model with linear eddy viscosity distribution in the lower layer and constant eddy viscosity in the upper layer (2LK), and a continuously varying eddy viscosity model (both in time and in the vertical) with Mellor‐Yamada level 2.5 closure (MY2.5). Both models compare favorably with observations during nearly homogeneous conditions, but show disagreement with data when the water column is strongly stratified. In the case of 2LK, the model overestimates the bottom stress and does not reproduce the observed velocity maximum at mid‐depth. This behavior is clearly related to the absence of buoyancy effects in the simplistic turbulence closure scheme. The advanced MY2.5 scheme, on the other hand, reproduces the observed velocity distribution and bottom stress well. However, the model also predicts an abrupt adjustment from the turbulent bottom boundary layer to a nearly nonturbulent region above which is not supported by our Richardson number estimates and observed turbulent dissipation rates. Potential reasons explaining the discrepancies between observations and MY2.5 include high‐frequency internal‐wave mixing and underestimation of the critical Richardson number used by the model to describe the transition from active to decaying turbulence.
Spectral UV Measurements at Sodankylä during 1990–2001
Authors: Lakkala K. , Kyrö E. , Turunen T.
Published: October 2003

A Brewer spectrophotometer MK II has measured UV irradiances since 1990 at Sodankylä (67°N,27°E), Finland. In this paper, the observed spectral features of the time series 1990–2001 are studied. In order to exclude the seasonal variation of irradiances due to the variation of solar zenith angle (SZA), only the narrow SZA interval from 63° to 65° was chosen. The data have been temperature, cosine, noise spike and wavelength‐shift corrected. In order to study long‐term changes in spectral UV irradiance, a linear regression line was fitted to the monthly mean irradiances from April to August. No statistically significant changes were observed for any months for the 12‐year period 1990–2001. One reason is that the period is rather short in comparison to the high natural inter‐annual variability of UV. The indistinct trend over this particular period could be also expected from the corresponding ozone changes: A decrease in the early 1990's with an increase toward more normal values in recent years, the smallest value occurring in the middle of the period. This makes the calculated UV changes highly dependent on the time period chosen. The biggest effect was seen in April, where the relative change at 305 nm varied from −5.0% to 12.1% per year for the periods 1993–2001 and 1990–1997, respectively. The analysis further shows that, although many other parameters, such as changes in cloudiness, aerosols, and albedo, contribute to UV changes, ozone has been a prominent factor at Sodankylä at the short wavelength end of the spectrum.
Experimental and field study of the effects of lithological contrasts on thrust‐related deformation
Authors: Teixell Antonio , Koyi Hemin A.
Published: October 2003

The influence of mechanical contrasts related to stratigraphy on thrust‐related deformation are investigated by sandbox modeling using combinations of granular materials possessing different mechanical properties and by structural analysis of a natural example from the Spanish Pyrenees. The models used in this study consist of loose sand and glass microbeads, in varied stratigraphic thicknesses and sequences, and the natural example consists of a weakening‐upward sequence of sandstones and carbonates. In both cases, layers of different composition had a mechanical significance and accommodated shortening differently. Model sand and natural sandstone exhibited most shortening by thrust imbrication irrespective of stratigraphic position, whereas glass microbeads and carbonates exhibited wider deformation zones and enhanced folding, accompanied by displacement reduction along thrust surfaces cutting them. Transitions of structural style were guided by the stratigraphy rather than by a simple unidirectional propagation from a step up. Layer‐parallel shortening was accommodated by diverse mechanisms but did not vary significantly in layers which had different properties. The magnitude with which mechanical contrasts were expressed in the models was influenced by the strength at the décollement zone. The effect of mechanical contrast was more profound in models shortened above a low‐friction décollement.
Baroclinic instability and transient features of mesoscale surface circulation in the Black Sea: Laboratory experiment
Authors: Blokhina M. D. , Afanasyev Y. D.
Published: October 2003

The circulation in the Black Sea is characterized by a strong basin‐wide current along the shore in the cyclonic direction (the Rim Current). Satellite and field data demonstrate that this circulation is subject to mesoscale variability in the form of meanders, eddies, and filaments. The unstable cyclonic boundary current was modeled in a new series of laboratory experiments on a rotating platform using a scaled model of the Black Sea. The dynamical similarity of the important dimensionless control parameters including the normalized Rossby deformation radius, the Rossby number, and the Ekman number was satisfied in the experiments. The results demonstrate the development of the baroclinic instability due to freshwater discharge imitating the river inflow in the Black Sea. The typical wavelength of the baroclinic instability observed in the experiments is analogous to that observed in the satellite images of the Black Sea when compared to characteristic dimensions of the basin. The cyclonic boundary current in the laboratory model is dynamically similar to the Rim Current. Persistent transient features of the circulation of the Black Sea, such as the so‐called Batumi Eddy and the Sevastopol Eddy as well as other features, were reproduced in the experiments when the background rotation rate of the system was varied.
Multiple scales and the relationship between density and spatial aggregation in littoral zone communities
Authors: Stoffels Rick J. , Closs Gerard P. , Burns Carolyn W.
Published: October 2003

Understanding the constraints on community composition at multiple spatial scales is an immense challenge to community and ecosystem ecologists. As community composition is basically the composite result of species’ spatial patterning, studying this spatial patterning across scales may yield clues as to which scales of environmental heterogeneity influence communities. The now widely documented positive interspecific relationship between ‘regional’ range and mean ‘local’ abundance has become a generalisation describing the spatial patterning of species at coarse scales. We address some of the shortcomings of this generalisation, as well as examine the cross‐scale spatial patterning (aggregation and density levels) of littoral‐benthic invertebrates in very large lakes. Specifically, we (a) determine whether the positive range‐abundance relationship can be reinterpreted in terms of the actual spatial structure of species distributions, (b) examine the relationship between aggregation and density across different spatial scales, and (c) determine whether the spatial patterning of species (e.g. low density/aggregated distribution) is constant across scales, that is, whether our interpretation of a species spatial pattern is dependent on the scale at which we choose to observe the system.

Spatial aggregation of littoral invertebrates was generally a negative function of mean density across all spatial scales and seasons (autumn and spring). This relationship may underlie positive range‐abundance relationships. Species that were uncommon and highly aggregated at coarse spatial scales can be abundant and approach random distributions at finer spatial scales. Also, the change in spatial aggregation of closely related taxa across spatial scales was idiosyncratic. The idiosyncratic cross‐scale spatial patterning of species implies that multiple scales of environmental heterogeneity may influence the assembly of littoral communities. Due to the multi‐scale, species‐specific spatial patterning of invertebrates, littoral zone communities form a complex spatial mosaic, and a ‘spatially explicit’ approach will be required by limnologists in order to link littoral‐benthic community patterns with ecosystem processes in large oligotrophic lakes.
Palatability, decomposition and insect herbivory: patterns in a successional old‐field plant community
Authors: Schädler Martin , Jung Gertraud , Auge Harald , Brandl Roland
Published: October 2003

We tested the hypothesis that selective feeding by insect herbivores in an old‐field plant community induces a shift of community structure towards less palatable plant species with lower leaf and litter tissue quality and may therefore affect nutrient cycling.

Leaf palatability of 20 herbaceous plant species which are common during the early successional stages of an old‐field plant community was assayed using the generalist herbivoresDeroceras reticulatum(Mollusca: Agriolomacidae) andAcheta domesticus(Ensifera: Gryllidae). Palatability was positively correlated with nitrogen content, specific leaf area and water content of leaves and negatively correlated with leaf carbon content and leaf C/N‐ratio.

Specific decomposition rates were assessed in a litter bag experiment. Decomposition was positively correlated with nitrogen content of litter, specific leaf area and water content of living leaves and negatively correlated with leaf C/N‐ratio.

When using phylogentically independent contrasts the correlations between palatability and decomposition versus leaf and litter traits remained significant (except for specific leaf area) and may therefore reflect functional relationships.

As palatability and decomposition show similar correlations to leaf and litter traits, the correlation between leaf palatability and litter decomposition rate was also significant, and this held even in a phylogenetically controlled analysis. This correlation highlights the possible effects of invertebrate herbivory on resource dynamics.

In a two‐year experiment we reduced the density of above‐ground and below‐ground insect herbivores in an early successional old‐field community in a two‐factorial design by insecticide application. The palatability ranking of plants showed no relationship with the specific change of cover abundance of plants due to the reduction of above‐ or below‐ground herbivory. Thus, changes in the dominance structure as well as potentially associated changes in the resource dynamics are not the result of differences in palatability between plant species. This highlights fundamental differences between the effects of insect herbivory on ecosystems and published results from vertebrate‐grazing systems.
Increase in the Production of Interleukin‐10 Early After Implantation is Related to the Success of Pregnancy
Authors: WU MING‐YIH , CHEN HSIN‐FU , CHEN SHEE‐UAN , CHAO KUANG‐HAN , YANG YU‐SHIH , HO HONG‐NERNG
Published: October 2003

PROBLEM: To study the correlation of interleukin (IL)‐10, IL‐11 leukemia inhibitory factor (LIF), placental growth factor (PlGF), and transforming growth factor (TGF)‐β and outcome of human pregnancy.  METHOD OF STUDY: We prospectively measured the serum levels of these cytokines in patients undergoing in vitro fertilization (IVF) programs. A total of 60 women (non‐pregnant, n=27; early abortions, n=12; normal pregnancies, n=21) were enrolled. 
RESULTS: There was no difference in the cytokines studied on D0 and D14 among the three groups of women. The increase in PlGF from D0 to D14 after human chorionic gonadotropin (hCG) injection was greater in pregnant women than in non‐pregnant women; however, the difference did not reach significance (P=0.068). The increase in IL‐10 production from D14 to D21 was significant in women with successful pregnancies compared to women in the abortion group.  CONCLUSIONS: This increase in IL‐10 may be important in sustaining a normal pregnancy early after implantation.
A randomized controlled trial of oral selegiline plus nicotine skin patch compared with placebo plus nicotine skin patch for smoking cessation
Authors: Biberman R. , Neumann R. , Katzir I. , Gerber Y.
Published: October 2003

Objectives  To compare the effect of oral selegiline plus nicotine patch with placebo plus nicotine patch on smoking cessation rates.

Design  Randomized double‐blind placebo‐controlled trial.

Setting  Three community‐based clinics.

Participants  One hundred and nine male and female smokers aged 18–55 years, who smoked at least 15 cigarettes/day.

Interventions  Oral selegiline, 2.5 mg, or placebo twice/day initiated 1 week before the quit day, followed by 5 mg oral selegiline or placebo twice daily for 26 weeks, plus active nicotine skin patch to all participants for the first 8 weeks only. Measures of continuous abstinence rates up to 52 weeks, withdrawal symptoms, blood pressure and adverse events incidence.

Findings  Twenty‐five per cent (14 of 56) were continuously abstinent for 52 weeks in the selegiline plus nicotine group compared with 11% (6 of 53) in the placebo plus nicotine group (P = 0.08). Craving for cigarettes was lower in the selegiline plus nicotine group 4 weeks after quit day (P = 0.02).

Conclusions  Adding selegiline to nicotine patch was associated with a doubling of the 52‐week continuous abstinence rate, but this difference was not statistically significant. Selegiline significantly reduced craving for cigarettes and appeared to mitigate the need for nicotine replacement therapy. The results suggest that selegiline is a promising drug for future smoking cessation research.
Prevalence of illicit drug use in young Australian women, patterns of use and associated risk factors
Authors: Turner Cathy , Russell Anne , Brown Wendy
Published: October 2003

Objectives  To estimate the prevalence of illicit drug use in young Australian women, determine their patterns of drug use and identify associated risk factors.

Methods  Data were collected in 2000 as part of the second survey of the youngest cohort in the Australian Longitudinal Study on Women's Health (n = 9512).

Results  Among women aged 22–27 years, 58% reported having used an illicit drug at some time with most (57%) having used cannabis. Amphetamines (16%), ecstasy/designer drugs (15%) and LSD (14%) were the next three most commonly used drugs. Four different patterns of drug use were identified: past users of cannabis only (39%); current users of cannabis only (17%); past multiple drug users (13%) and current multiple drug users (31%). Living in a de‐facto relationship or never being married, living with non‐family members, a history of physical abuse, sexual intercourse, smoking and binge drinking were associated significantly with exclusive use of cannabis and with use of multiple drugs compared to never using illicit drugs. Living with a partner, experience of sexual or emotional abuse, pregnancy, diagnosis of depression and taking sleeping medication were associated significantly with being a multiple drug user, but not for exclusive cannabis use. Multiple drug users had, on average, used cannabis 2–3 years before using any other drug.

Conclusions  Given the strong association found between smoking, heavy drinking and drug use of varied patterns, public health initiatives targeted at preventing young women from smoking and drinking should additionally target illicit drug use.
Genes, disease and medicine
Authors: DYKES COLIN W.
Published: October 2003

1Information and technologies derived from genomic research are beginning to revolutionize the study of disease. It is now being predicted that the human genome sequencing project will be more than 90% complete by the end of this decade and that most of the major genes involved in common diseases will have been identified by that time. Correlations between genetic mutations, disease susceptibility, and adverse reactions to drugs are already being established and it seems inevitable that this will lead to the development of novel therapies accurately targeted at subsets of patients most likely to show a favourable response.

2Targeted therapies present a significant challenge to the pharmaceutical industry because the potential market for such drugs is likely to be smaller than for current ‘phenotypic’ treatments. However, application of molecular genetic technologies may allow parallel reductions in development costs since it should be more straightforward to demonstrate efficacy and safety in accurately selected patient groups, reducing the requirement for large clinical trials.

3Gene‐based diagnostics have the potential to radically improve medical practice, and progress in genetic testing technology has been impressive. Yet there is growing concern that commercial and other pressures may result in genetic testing being made widely available before the biological consequences of mutations in disease susceptibility genes are fully understood and before the legal, ethical and psychological consequences of testing have been fully debated.
Relevance of induction of human drug‐metabolizing enzymes: pharmacological and toxicological implications
Authors: PARK B. K. , KITTERINGHAM N. R. , PIRMOHAMED M. , TUCKER G. T.
Published: October 2003

1Human drug‐metabolizing systems can be induced, or activated, by a large number of exogenous agents including drugs, alcohol, components in the diet and cigarette smoke, as well as by endogenous factors.

2Such perturbation of enzyme activity undoubtedly contributes to both intra‐ and inter‐individual variation both with respect to the rate and route of metabolism for a particular drug. Induction may, in theory, either attenuate the pharmacological response or exacerbate the toxicity of a particular drug, or both.

3The clinical impact of enzyme induction will depend upon the number of different enzyme isoforms affected and the magnitude of the inductive response within an individual, and also on the therapeutic indices of the affected substrates.

4The toxicological implications will be determined either by any change in the route of metabolism, or by a disturbance of the balance between activation and detoxication processes, which may be isozyme selective.
Pharmacokinetics of 619C89, a novel neuronal sodium channel inhibitor, in acute stroke patients after loading and discrete maintenance infusions
Authors: HUSSEIN Z. , FRASER I. J. , LEES K. R. , MUIR K. W. , LUNNON M. W. , HOBBIGER S. F. , POSNER J.
Published: October 2003

1This was a multi‐centre, placebo controlled, randomized, dose‐escalating design study in which five dosing regimens of 619C89/placebo were evaluated in 48 stroke patients. Loading infusions of 0.5, 1, 1.5, 2 and 2.5 mg kg−1 over 1 h were followed by respective maintenance infusions of 0.25, 0.5, 0.75, 1 and 1.25 mg kg−1 over 30 min at 8 hourly intervals for 3 days.

2Plasma concentrations of 619C89 and its N‐oxide, 341C90, and N‐demethylated, 78C90, metabolites were assayed using an LC–MS–MS method. Plasma concentration‐time profiles after the final maintenance infusion were subjected to conventional noncompartmental pharmacokinetic analysis.

3For 619C89, geometric CL means ranged between 0.71 and 0.99 l h−1 kg−1 for maintenance infusions up to 1.25 mg kg−1 over 30 min, with an overall mean of 0.85 l h−1 kg−1 (95% CI: 0.70–1.04 l h−1 kg−1). Geometric Vss means ranged between 13.2 and 27.9 l kg−1 for the same doses, with an overall mean of 22.5 l kg−1 (95% CI: 16.4–30.9 l kg−1). The ANOVA results revealed that neither CL, Vss nor t1/2 were significantly different across the five dosing regimens (P values: 0.82, 0.54 and 0.61, respectively).

4Average AUC for 341C90 was 270% and that for 78C90 was 62% of the AUC for 619C89. The AUCm/AUCp‐ratios were similar at all dose levels for each metabolite. Values of t1/2 for 341C90 were similar to those of 619C89 whereas t1/2 for 78C90 was about three‐fold longer than that of parent drug.

5In conclusion, the pharmacokinetics of 619C89 are independent of dose in acute stroke patients. The pharmacokinetics of 341C90 are probably formation rate‐limited and those of 78C90 are elimination rate‐limited and are also dose‐independent.
Transgenic mouse models in carcinogenesis: interaction of c‐myc with transforming growth factor α and hepatocyte growth factor in hepatocarcinogenesis
Authors: THORGEIRSSON SNORRI S. , SANTONI‐RUGIU ERIC
Published: October 2003

1Overexpression of the c‐myc oncogene is associated with a variety of both human and experimental tumours, and cooperation of other oncogenes and growth factors with the myc family are critical in the evolution of the malignant phenotype.

2Double transgenic mice bearing fusion genes consisting of mouse albumin enhancer/promoter‐mouse c‐myc cDNA and mouse metallothionein 1 promoter‐human transforming growth factor (TGF‐α) cDNA were generated to investigate the interaction of these genes in hepatic oncogenesis and to provide a general paradigm for characterizing the interaction of nuclear oncogenes and growth factors in tumourigenesis.

3Coexpression of c‐myc and TGF‐α as transgenes in the mouse liver resulted in a tremendous acceleration of neoplastic development in this organ as compared to expression of either of these transgenes alone. The two distinct cellular reactions that occurred in the liver of the double transgenic mice prior to the appearance of liver tumours were dysplastic and apoptotic changes in the existing hepatocytes followed by emergence of multiple focal lesions composed of both hyperplastic and dysplastic cell populations.

4These observations suggest that the interaction of c‐myc and TGF‐α, during development of hepatic neoplasia contributes to the selection and expansion of the preneoplastic cell populations which consequently increases the probability of malignant conversion.

5We have now extended these studies and examined the interaction of hepatocyte growth factor (HGF) with c‐myc during hepatocarcinogenesis in the transgenic mouse model. While sustained overexpression of c‐myc in the liver leads to cancer, coexpression of HGF and c‐myc in the liver delayed the appearance of preneoplastic lesions and prevented malignant conversion. Similarly, tumour promotion by phenobarbitone was completely inhibited in the c‐myc/HGF double transgenic mice whereas phenobarbitone was an effective tumour promoter in the c‐myc single transgenic mice.

6The results indicate that HGF may function as a tumour suppressor during early stages of liver carcinogenesis, and suggest the possibility of therapeutic application for this cytokine. Furthermore, we show for the first time that interaction of c‐myc with HGF or TGF‐α results in profoundly different outcomes of the neoplastic process in the liver.
Single‐dose pharmacokinetics of ampicillin and tobramycin administered by hypodermoclysis in young and older healthy volunteers
Authors: CHAMPOUX N. , DU SOUICH P. , RAVAOARINORO M. , PHANEUF D. , LATOUR J. , CUSSON J. R.
Published: October 2003

1To test the feasibility of administering antibiotics by subcutaneous infusion to the elderly, we compared the pharmacokinetics of tobramycin (single dose of 80 mg) given by hypodermoclysis (HDC) with the kinetics of the antibiotic injected intravenously (i.v.) in 10 young (<50 years old) and 10 elderly (>65 years old) healthy volunteers. Similar studies were performed with ampicillin (single dose of 1 g) in 12 young and 10 older healthy volunteers.

2Compared with the i.v. route, HDC delayed the time to reach the maximal plasma concentration (tmax) of tobramycin in young volunteers: 32±6 (s.d.) min vs 88±46, P<0.005, and older volunteers: 27±4 min vs 89±15, P<0.005. Administration of the antibiotics by HDC was well tolerated. The plasma concentration of tobramycin 30 min after the end of infusion (C60) was lower (P<0.05) following HDC than after the i.v. route in both young, 2.2±0.7 vs 3.5±0.8 μg ml−1, and elderly subjects, 2.2±0.8 vs 3.8±0.9. μg ml−1.

3The area under the curve (AUC) of tobramycin given by HDC was slightly smaller than when given i.v., i.e. in young subjects: 740±225 (s.d.) vs 893±223 μg ml−1 min, NS, and in the elderly: 980±228 vs 1056±315 μg ml−1 min, NS.

4When ampicillin was administered by HDC, the tmax was also delayed in young volunteers: 45±18 vs 23±6 min, and in the elderly: 49±18 vs 27±4 min, P<0.005, the AUC was greater by HDC than i.v. in the young volunteers: 4527±1658 μg ml−1 min vs 3810±1033 μg ml−1 min and in the elderly: 6795±2094 μg ml−1 min vs 4217±1518 μg ml−1 min, and the C60 was higher by HDC in the young: 27±7 vs 24±9 μg ml−1, and in the elderly: 32±9 vs 23±11 μg ml−1, P<0.05.

5In conclusion, HDC delays the entry of the antibiotic into the systemic circulation, but did not affect the amount available. HDC was well tolerated and could become an adequate method for antibiotic administration to the elderly.
Clinical pharmacology of β3‐adrenoceptors
Authors: LIPWORTH BRIAN J.
Published: October 2003

1An atypical non β1/β2‐adrenoceptor (AR) subtype (β3‐AR) has been identified which is selectively stimulated by a group of ligands which mediate lipolytic and thermic responses in brown and white adipose tissue.

2Molecular studies have shown that β3‐AR in man are mainly expressed in visceral adipocytes, and to a lesser extent in gall‐bladder and colon. In vitro studies with β3‐AR agonists have shown activity at other sites including skeletal muscle and myocardium.

3Regulation of β3‐AR may differ from β1/β2‐AR subtypes in that continuous agonist exposure does not result in receptor down‐regulation.

4A polymorphism of the human β3‐AR gene (Trp64Arg) has been identified which is associated with obesity, insulin resistance and an earlier onset of non‐insulin‐dependent diabetes mellitus (NIDDM). Studies are required to establish whether expression of the mutant gene results in altered metabolic responses to β3‐AR stimulation in man.

5There is accumulating evidence to support a therapeutic role of β3‐AR agonists in NIDDM because of anti‐obesity and anti‐diabetic activity, as a consequence of thermogenic effects as well as increased insulin sensitivity and glucose tolerance.

6Selectivity studies with BRL35135 and isoprenaline in humans have demonstrated a β3‐AR mediated component to thermogenesis which is dissociated from β1/β2‐mediated effects on carbohydrate and fat metabolism. Similar studies have suggested a functional β3‐AR mediating cardiac but not airway responses in humans. An evaluation of β3‐AR agonists in irritable bowel syndrome may be warranted in view of colonic antimotility properties in vitro.