bluuebunny/crossref_metadata_2025 huggingface dataset:
Interfacial properties of Lennard-Jones chains by direct simulation and density gradient theory
Authors: Duque Daniel , Pàmies Josep C. , Vega Lourdes F.
Published: November 2004

We perform a series of molecular dynamics simulations of Lennard-Jones chains systems, up to tetramers, in order to investigate the influence of temperature and chain length on their phase separation and interfacial properties. Simulation results serve as a test to check the accuracy of a statistical associated fluid theory (soft-SAFT) coupled with the density gradient theory. We focus on surface tension and density profiles. The simulations allow us to discuss the success and limitations of the theory and how to estimate the only adjustable parameter, the influence parameter. This parameter is obtained by fitting the surface tension, and then used to obtain the density profiles in a predictive manner. A good agreement is found if the temperature dependence of this parameter is neglected.
Exact decoupling of the Dirac Hamiltonian. II. The generalized Douglas–Kroll–Hess transformation up to arbitrary order
Authors: Reiher Markus , Wolf Alexander
Published: November 2004

In order to achieve exact decoupling of the Dirac Hamiltonian within a unitary transformation scheme, we have discussed in part I of this series that either a purely numerical iterative technique (the Barysz–Sadlej–Snijders method) or a stepwise analytic approach (the Douglas–Kroll–Hess method) are possible. For the evaluation of Douglas–Kroll–Hess Hamiltonians up to a pre-defined order it was shown that a symbolic scheme has to be employed. In this work, an algorithm for this analytic derivation of Douglas–Kroll–Hess Hamiltonians up to any arbitrary order in the external potential is presented. We discuss how an estimate for the necessary order for exact decoupling (within machine precision) for a given system can be determined from the convergence behavior of the Douglas–Kroll–Hess expansion prior to a quantum chemical calculation. Once this maximum order has been accomplished, the spectrum of the positive-energy part of the decoupled Hamiltonian, e.g., for electronic bound states, cannot be distinguished from the corresponding part of the spectrum of the Dirac operator. An efficient scalar-relativistic implementation of the symbolic operations for the evaluation of the positive-energy part of the block-diagonal Hamiltonian is presented, and its accuracy is tested for ground-state energies of one-electron ions over the whole periodic table. Furthermore, the first many-electron calculations employing sixth up to fourteenth order DKH Hamiltonians are presented.
The “JK-only” approximation in density matrix functional and wave function theory
Authors: Kollmar Christian
Published: November 2004

Various energy functionals applying the “JK-only” approximation which leads to two-index two-electron integrals instead of four-index two-electron integrals in the electron–electron interaction term of the electronic energy are presented. Numerical results of multiconfiguration self-consistent field calculations for the best possible “JK-only” wave function are compared to those obtained from the pair excitation multiconfiguration self-consistent (PEMCSCF) method and two versions of density matrix functional theory. One of these is derived making explicit use of some necessary conditions for N representability of the second-order density matrix. It is shown that this method models the energy functional based on the best possible “JK-only” wave function with good accuracy. The calculations also indicate that only a minor fraction of the total correlation energy is incorporated by “JK-only” approaches for larger molecules.
Collisionally assisted, highly selective laser isotope separation of carbon-13
Authors: Polianski M. , Boyarkin O. V. , Rizzo T. R.
Published: November 2004

We have further developed our recently reported two-laser technique for highly selective molecular isotope separation of carbon-13 [Boyarkin, Kowalczyk, and Rizzo, J. Chem. Phys. 118, 93 (2003)] with the objective of increasing the yield. An essential feature of this approach in its original conception is the significant increase of isotopic selectivity that occurs through collisions during the time between the overtone preexcitation laser pulse and the multiphoton dissociation pulse. We demonstrate here that under certain conditions, this collisional enhancement of the selectivity works equally well when the two pulses are overlapped in time, allowing the overall isotopic selectivity of the process to remain high while achieving a significant increase in the absolute dissociation yield. We also find that proper shaping of the CO2 laser dissociation pulse makes the fluence required for dissociation sufficiently low to allow irradiation of a large reaction volume by unfocused laser beams. Together, these factors may make this laser isotope separation scheme competitive with existing separation methods.
Vibrational mode and collision energy effects on reaction of H2CO+ with C2D4
Authors: Liu Jianbo , Van Devener Brian , Anderson Scott L.
Published: November 2004

We report the effects of collision energy (Ecol) and five different H2CO+ vibrational modes on the reaction of H2CO+ with C2D4 over the center-of-mass Ecol range from 0.1 to 2.1 eV. Properties of various complexes and transition states were also examined computationally. Seven product channels are observed. Charge transfer (CT) has the largest cross section over the entire energy range, substantially exceeding the hard sphere cross section at high energies. Competing with CT are six channels involving transfer of one or more hydrogen atoms or protons and one involving formation of propanal, followed by hydrogen elimination. Despite the existence of multiple deep wells on the potential surface, all reactions go by direct mechanisms, except at the lowest collision energies, where short-lived complexes appear to be important. Statistical complex decay appears adequate to account for the product branching at low collision energies, however, even at the lowest energies, the vibrational effects are counter to statistical expectations. The pattern of Ecol and vibrational mode effects provide insight into factors that control reaction and interchannel competition.
Statistical mechanics of wormlike polymers from a new generating function. II. The force-elongation relationship
Authors: Carri Gustavo A.
Published: November 2004

In a recent paper [J. Chem. Phys., 121, 6064 (2004)] we developed a method to solve the wormlike chain model of semiflexible polymers. In this note we apply this method to evaluate the force-elongation relationship. It is found that our result agrees qualitatively with experimental data and the results obtained using three other theoretical treatments of semiflexible polymers for all values of the semiflexibility parameter. Quantitative comparisons are presented in the limit of long chains where good quantitative agreement with experimental data and two of the aforementioned theoretical studies are observed for elongations up to 60%, approximately. The limit of stiff chains was also studied and good quantitative agreement with other theoretical results is observed. These results complement the ones reported in our previous paper and show the robustness of our method.
Statistical analysis of the velocity field in a mechanical precessing jet flow
Authors: Mi J. , Nathan G. J.
Published: November 2004

An experimental investigation of a precessing jet issuing from a mechanically rotating nozzle directed at an angle of α=45° relative to the axis of rotation is reported. Both conventional and conditional statistics of the velocity field of the jet were measured using a combined hot-wire and cold-wire (to identify any reverse flow) probe. Three distinct values (≈0.005, 0.01, and 0.02) of the precession Strouhal number Stp (≡ rotation frequency × nozzle diameter / jet exit bulk velocity) were used to assess the effect of varying Stp. The measurements reveal that the Strouhal number in general has significant influence on the entire mixing field generated by a precessing jet. The occurrence of precession at all the Strouhal numbers of investigation produces a central recirculation zone at x⩽7d, where x is a distance measured from the rotating nozzle exit. A critical Strouhal number, i.e., Stp,cr≈0.008 for the present case, is identified: at Stp⩾Stp,cr the core jet converges to the axis of rotation while at Stp⩾Stp,cr it does not. The characteristics of the turbulent flow in the near and intermediate regions are quite different and depend upon the magnitude of Stp. The near-field region, x∕d⩽10–15, is dominated by a regime of global precession of the entire jet. As a result, the large-scale entrainment of the ambient fluid is substantially enhanced while the fine-scale turbulent mixing is suppressed. Under the supercritical regime (i.e., Stp⩾Stp,cr), the jet in the far field resembles some features of the nonprecessing counterpart. Nevertheless, significant differences still retain in the statistical properties.
Nonlinear evolution of Mack modes in a hypersonic boundary layer
Authors: Chokani Ndaona
Published: November 2004

In hypersonic boundary layer flows the nonlinear disturbance evolution occurs relatively slowly over a very long length scale and has a profound effect on boundary layer transition. In the case of low-level freestream disturbances and negligible surface roughness, the transition is due to the modal growth of exponentially growing Mack modes that are destabilized by wall cooling. Cross-bicoherence measurements, derived from hot-wire data acquired in a quiet hypersonic tunnel, are used to identify and quantify phase-locked, quadratic sum and difference interactions involving the Mack modes. In the early stages of the nonlinear disturbance evolution, cross-bicoherence measurements indicate that the energy exchange between the Mack mode and the mean flow first occurs to broaden the sidebands; this is immediately followed by a sum interaction of the Mack mode to generate the first harmonic. In the next stages of the nonlinear disturbance evolution, there is a difference interaction of the first harmonic, which is also thought to contribute to the mean flow distortion. This difference interaction, in the latter stages, is also accompanied by a difference interaction between Mack mode and first harmonic, and a sum interaction, which forces the second harmonic. Analysis using the digital complex demodulation technique, shows that the low-frequency, phase-locked interaction that is identified in the cross bicoherence when the Mack mode and first harmonic have large amplitudes, arises due to the amplitude modulation of Mack mode and first harmonic.
Predissociation spectroscopy of the argon-solvated H5O2+ “zundel” cation in the 1000–1900 cm−1 region
Authors: Headrick Jeffrey M. , Bopp Joseph C. , Johnson Mark A.
Published: November 2004

Predissociation spectra of the H5O2+⋅Ar1,2 cluster ions are reported in the 1000–1900 cm−1 region. The weakly bound argon atoms enable investigation of the complex in a linear action mode, and the resulting spectra are much simpler than those reported previously in this region [Asmis et al., Science 299, 1375 (2003) and Fridgen et al., J. Phys. Chem. A 108, 9008 (2004)], which were obtained using infrared multiphoton dissociation of the bare complex. The observed spectrum consists of two relatively narrow bands at 1080 and 1770 cm−1 that are likely due to excitation of the shared proton and intramolecular bending vibrations of the two water molecules, respectively. The narrow linewidths and relatively small (60 cm−1) perturbation introduced by the addition of a second argon atom indicate that the basic “zundel” character of the H5O2+ ion survives upon complexation.
Near-infrared electronic spectrum of CH2+
Authors: Gottfried Jennifer L. , Oka Takeshi
Published: November 2004

Four vibronic bands of the Ã 2B1(Πu)←X̃ 2A1 electronic transition of CH2+ have been observed in the near infrared from ∼11 000–13 000 cm−1 using a highly sensitive spectrometer based on a Ti:sapphire laser and a positive column plasma. The two states are derived from the lowest Πu2 state of the linear conformation as a result of a strong Renner–Teller effect. As expected, the rovibronic structure of the CH2+ spectrum is very similar to that of the isoelectronic BH2 radical reported by Herzberg and Johns. Results of a preliminary analysis are given in which the rotational structures of the two states are treated independently, the ground state as a near-prolate asymmetric rotor and the excited state as a linear molecule.
A Methodology for Assessing National Sustainable Development Strategies
Authors: Cherp Aleg , George Clive , Kirkpatrick Colin
Published: November 2004

At the Rio Earth Summit of 1992 governments undertook to develop and adopt national sustainable development strategies as a key component of implementing the goals of Agenda 21. Only partial progress was reported at the 2002 World Summit in Johannesburg, with uncertainty as to the effectiveness of those strategies that had been introduced. This paper describes a methodology for assessing a country's progress in implementing a national sustainable development strategy (NSDS) and for identifying potential areas for improvement. Five key principles of sustainable development and strategic planning are identified, and a set of assessment criteria are proposed for testing their implementation. The results of applying the methodology in two Eastern European countries, Belarus and Slovakia, are reported. These case studies suggest that the proposed NSDS assessment methodology has considerable potential for strengthening sustainability planning at the national level. The effectiveness of the NSDS assessment methodology in strengthening national processes for sustainable development and strategic planning will also require greater transparency and accountability in governance practices. This suggests that progress in improving the quality of NSDS processes is likely to be conditional on broader considerations of institution building and governance reform.
Europeanisation and the Uneven Convergence of Environmental Policy: Explaining the Geography of EMAS
Authors: Perkins Richard , Neumayer Eric
Published: November 2004

In this paper we seek to advance current understanding of uneven convergence in the context of EU environmental policy, and specifically, the Eco-Management and Audit Scheme (EMAS). Using a large-sample, quantitative methodology, we examine three broad sets of determinants hypothesised to influence geographic patterns of policy convergence: (1) cross-national market integration; (2) compatibility between the domestic regulatory context and European policy requirements; and (3) bottom-up pressure from market and societal actors. Our analysis provides empirical support for all three hypothesised determinants. Measures of import–export ties, regulatory burden, past policy adoptions, environmental demand from civil society, and levels of economic productivity are all found to be statistically significant predictors of national EMAS counts. Against a backdrop of geographically diverse regulatory institutions, societal conditions, and trading relationships, we conclude that unevenness is an inevitable feature of Europeanisation.
Policy toward Novice, Serial, and Portfolio Entrepreneurs
Authors: Westhead Paul , Ucbasaran Deniz , Wright Mike , Binks Martin
Published: November 2004

Support is being provided to increase the pool of novice entrepreneurs who have no prior business ownership experience. Policymakers and practitioners are, however, considering whether to allocate resources towards portfolio and serial entrepreneurs who have prior business ownership experience. To inform this policy debate, similarities and differences between novice, serial, and portfolio entrepreneurs in Scotland and their 354 surveyed firms are highlighted. Evidence suggests that portfolio entrepreneurs have more diverse resources than either serial or novice entrepreneurs. On average, portfolio entrepreneurs appear to offer more attractive growth prospects than other entrepreneurs. A case for support tailored to the aspirations and needs of novice, serial, and portfolio entrepreneurs is presented.
Mixing the Grant Cocktail: Towards an Understanding of the Outcomes of Financial Support to Small Firms
Authors: McGuinness Seamus , Hart Mark
Published: November 2004

One of the key policy objectives of government at national and regional level, is to overcome the constraints preventing local industry achieving greater competitiveness in the international market-place. This paper examines the impact of grant assistance to Northern Ireland small firms delivered over the period 1994–97 by the former Local Enterprise Development Unit through its Growth Business Support Programme (GBSP). Previous work by the authors showed that there was some tentative evidence to suggest a link between employment growth and grant aid provided to very small firms (fewer than 10 employees) assisted under the GBSP. The central objective of the empirical work reported in this paper is to extend the previous analysis by understanding the extent to which the value of financial assistance influences growth (employment, turnover, and productivity measures) and if differential impacts arise depending on the nature and timing (lag structures) of the grant assistance.
Support Services for SMEs: Does the ‘Franchisee’ Make a Difference to the Business Link Offer?
Authors: Bennett Robert , Robson Paul
Published: November 2004

Business Link is a government-financed support body for small firms in England in which local franchisees provide a range of business advice services. Franchisees must act as independent bodies with the franchise as their ‘only line of business’. Yet franchisees are of various types: some are de facto partnerships, some are linked to chambers of commerce, some are linked to other bodies, and some are private sector companies. Although all are arm's length of any related organisation, and work to a standardised contract and target regime, it is possible that the type of franchisee makes a difference to the management of the franchise, how the targets are prioritised, and how this affects referrals and links to other service providers. This in turn could be reflected in the level of market penetration and user experiences. This paper assesses, using analysis of variance, the relationship of the type of franchisee with propensity to charge fees, market penetration, impact, and customer satisfaction. It shows that there are significant effects of the franchise on client impact and satisfaction, but not on market penetration. In general, chambers of commerce and private sector franchisees perform best. But there is immense variability of all measures of performance, with all franchise types providing both high performing and poorly performing Business Links. This variability, which is of long standing, provides one of the strongest challenges to the credibility and justification for providing a government-financed support system. Within this pattern, fees in general have little statistical relationship with client satisfaction.
Location of Casualty Collection Points
Authors: Drezner Tammy
Published: November 2004

In this paper I find the best location of casualty collection points (CCPs). CCPs are expected to become operational in case of a human-made or natural disaster with mass casualties, such as a high-magnitude earthquake. Five objective functions are suggested and analyzed: p-median, p-center, p-maxcover, min-variance, and Lorenz curve. Multiobjective models are also analyzed. To illustrate the location problem, the models are applied to a scenario based on a large earthquake hitting Orange County, CA as a case study. The optimal locations for the CCPs using the objective functions are found, analyzed, and compared.
A genetic analysis of parasite resistance traits in a tropically adapted line of Bos taurus
Authors: Henshall J. M.
Published: November 2004

For cattle raised in tropical and subtropical environments, production can be limited by the susceptibility of many breeds to parasites. Chemical control, coupled with the use of breeds with higher levels of resistance to parasites, allows beef production to be a viable industry, but at a cost. The Hereford Shorthorn (HS) line of beef cattle at Rockhampton has been used extensively to study genetic aspects of parasite resistance. The hypothesis that a gene with a large effect on resistance to cattle ticks is segregating in this line of cattle has been raised in the past, and is considered again here, with the benefit of data recorded up to the late 1990s. A model in which no major gene effect is fitted provides a satisfactory fit to the data, providing little evidence in support of the segregation of major genes for resistance to either ticks or worms in the HS line. This conclusion is supported by the lack of animals of extreme resistance in later generations, an unlikely result if key animals are assumed to be homozygous in earlier generations.
Evaluation of the impacts of deep open drains on groundwater levels in the wheatbelt of Western Australia
Authors: Ali Riasat , Hatton Tom , George Richard , Byrne John , Hodgson Geoff
Published: November 2004

Abstract. Over one million hectares of the wheatbelt of Western Australia (WA) are affected by secondary salinisation and this area is expected to increase to between 3 and 5 million hectares if current trends continue. Deep open drains, as an engineering solution to dryland salinity, have been promoted over the past few decades; however, the results of initial experiments were variable and no thorough analysis has been done. This research quantifies the effects of deep open drains on shallow and deep groundwater at farm and subcatchment level.
Analysis of rainfall data showed that the only dry year (below average rainfall) after the construction of drainage in the Narembeen area of WA (in 1998 and 1999) was 2002. The dry year caused some decline in groundwater levels in the undrained areas but had no significant impact in the drained areas. The study found that the effect of drains on the groundwater levels was particularly significant if the initial water levels were well above the drain bed level, permeable materials were encountered, and drain depth was adequate (2.0–3.0 m). Visual observations and evidence derived from this study area suggested that if the drain depth cut through more permeable, macropore-dominated siliceous and ferruginous hardpans, which exist 1.5–3 m from the soil surface, its efficiency exceeded that predicted by simple drainage theory based on bulk soil texture. The effect of drains often extended to distances away (>200 m) from the drain. Immediately following construction, drains had a high discharge rate until a new hydrologic equilibrium was reached. After equilibrium, flow largely comprised regional groundwater discharge and was supplemented by quick responses driven by rainfall recharge. Comparison between the hydrology of the drained and undrained areas in the Wakeman subcatchment showed that, in the valley floors of the drained areas, the water levels fluctuated mainly between 1.5 and 2.5 m of the soil surface during most of the year. In the valley floors of the undrained areas, they fluctuated between 0 and 1 m of the soil surface. The impact of an extreme rainfall event (or unusual wet season) on drain performance was predicted to vary with distance from the drain. Within 100 m from the drain, water levels declined relatively quickly, whereas it took a year before the water levels at 200–300 m away from the drain responded. The main guidelines that can be recommended based on the results from this study are the drain depth and importance of ferricrete layer. In order to be effective, a drain should be more than 2 m deep and it should cut through the ferricrete layer that exists in many landscapes in the wheatbelt.
Seed coat specific weight in Lupinus angustifolius: influence of genotype and environment and relationship with seed coat proportion
Authors: Mera M. , Jerez R. , Miranda H. , Rouanet J. L.
Published: November 2004

Abstract. The relatively high seed coat proportion of the narrow-leafed lupin reduces its economic value. This character has been shown to be affected by seed weight, and this limits the use of seed coat proportion as a selection criterion. We examined the variation for seed coat specific weight, a potential alternative selection criterion, and tested its relationship with seed coat proportion and seed weight. Seeds were sampled from mainstem pods of 14 winter-sown genotypes of Lupinus angustifolius L. grown at 4 southern Chile sites over 2 years. Seed coat specific weight had an overall mean of 30.1 mg/cm2. Highly significant genotypic effects were found (range 28.9–32.1 mg/cm2). The ranges for sites and years were 29.1–31.1 and 28.9–31.2 mg/cm2, respectively. Genotypes interacted significantly with years, but not with sites. Broad-sense heritability was 0.59, a value that predicts a good response to selection for this character. Seed coat specific weight was weakly correlated (rph = 0.11*) with seed coat proportion, and was not associated with mean seed weight. Seed coat proportion was negatively correlated with mean seed weight (rph = –0.75***) and had high broad-sense heritability (0.95). The correlation between seed coat specific weight and a theoretical seed coat thickness, calculated under the assumptions of equal mass density of seed coat, cotyledons, and embryo, and a spherical-shaped seed, was r = 0.14*. Phenotypic and genotypic correlations between seed coat specific weight and number of seeds per pod were 0.41 and 0.84, respectively. Our results indicate that selection for low seed coat proportion will lead to larger seeded genotypes, but will not reduce seed coat specific weight. Selection for low seed coat proportion after crosses would presumably be effective in reducing seedcoat specific weight if all segregating materials were uniformly large seeded, but that scenario is unrealistic. The evidence presented here suggests that selection for low seed coat specific weight (or measures correlated with it) in segregating populations will be necessary in order to increase the proportion of higher value kernels in seeds and to improve the economic yield of lupins.
The VASP tetramerization domain is a right-handed coiled coil based on a 15-residue repeat
Authors: Kühnel Karin , Jarchau Thomas , Wolf Eva , Schlichting Ilme , Walter Ulrich , Wittinghofer Alfred , Strelkov Sergei V.
Published: November 2004

The vasodilator-stimulated phosphoprotein (VASP) is a key regulator of actin dynamics. We have determined the 1.3-Å resolution crystal structure of the 45-residue-long tetramerization domain (TD) from human VASP. This domain forms a right-handed α-helical coiled-coil structure with a similar degree of supercoiling as found in the widespread left-handed coiled coils with heptad repeats. The basis for the right-handed geometry of VASP TD is a 15-residue repeat in its amino acid sequence, which reveals a characteristic pattern of hydrophobic residues. Hydrophobic interactions and a network of salt bridges render VASP TD highly thermostable with a melting point of 120°C.
Costimulatory B7-H1 in renal cell carcinoma patients: Indicator of tumor aggressiveness and potential therapeutic target
Authors: Thompson R. Houston , Gillett Michael D. , Cheville John C. , Lohse Christine M. , Dong Haidong , Webster W. Scott , Krejci Kent G. , Lobo John R. , Sengupta Shomik , Chen Lieping , Zincke Horst , Blute Michael L. , Strome Scott E. , Leibovich Bradley C. , Kwon Eugene D.
Published: November 2004

Expression of B7-H1, a costimulating glycoprotein in the B7 family, is normally restricted to macrophage-lineage cells, providing a potential costimulatory signal source for regulation of T cell activation. In contrast, aberrant expression of B7-H1 by tumor cells has been implicated in impairment of T cell function and survival, resulting in defective host antitumoral immunity. The relationship between tumor-associated B7-H1 and clinical cancer progression is unknown. Herein, we report B7-H1 expression by both renal cell carcinoma (RCC) tumors of the kidney and RCC tumor-infiltrating lymphocytes. In addition, our analysis of 196 clinical specimens reveals that patients harboring high intratumoral expression levels of B7-H1, contributed by tumor cells alone, lymphocytes alone, or tumor and/or lymphocytes combined, exhibit aggressive tumors and are at markedly increased risk of death from RCC. In fact, patients with high tumor and/or lymphocyte B7-H1 levels are 4.5 times more likely to die from their cancer than patients exhibiting low levels of B7-H1 expression (risk ratio 4.53; 95% confidence interval 1.94–10.56;P< 0.001.) Thus, our study suggests a previously undescribed mechanism whereby RCC may impair host immunity to foster tumor progression. B7-H1 may prove useful as a prognostic variable for RCC patients both pre- and posttreatment. In addition, B7-H1 may represent a promising target to facilitate more favorable responses in patients who require immunotherapy for treatment of advanced RCC.
Adapting to an invasive species: Toxic cane toads induce morphological change in Australian snakes
Authors: Phillips Ben L. , Shine Richard
Published: November 2004

The arrival of invasive species can devastate natural ecosystems, but the long-term effects of invasion are less clear. If native organisms can adapt to the presence of the invader, the severity of impact will decline with time. In Australia, invasive cane toads (
Bufo marinus
) are highly toxic to most snakes that attempt to eat them. Because snakes are gape-limited predators with strong negative allometry for head size, maximum relative prey mass (and thus, the probability of eating a toad large enough to be fatal) decreases with an increase in snake body size. Thus, the arrival of toads should exert selection on snake morphology, favoring an increase in mean body size and a decrease in relative head size. We tested these predictions with data from specimens of four species of Australian snakes, collected over >80 years. Geographic information system layers provided data on the duration of toad exposure for each snake population, as well as environmental variables (latitude, precipitation, and temperature). As predicted, two toad-vulnerable species (
Pseudechis porphyriacus
and
Dendrelaphis punctulatus
) showed a steady reduction in gape size and a steady increase in body length with time since exposure to toads. In contrast, two species at low risk from toads (
Hemiaspis signata
and
Tropidonophis mairii
) showed no consistent change in these morphological traits as a function of the duration of toad exposure. These results provide strong evidence of adaptive changes in native predators as a result of the invasion of toxic prey.
ErbB2 is required for ductal morphogenesis of the mammary gland
Authors: Jackson-Fisher Amy J. , Bellinger Gary , Ramabhadran Rajani , Morris Jacqueline K. , Lee Kuo-Fen , Stern David F.
Published: November 2004

The
ERBB2
/
HER2
/
NEU
receptor tyrosine kinase gene is amplified in up to 30% of human breast cancers. The frequent and specific selection of this receptor kinase gene for amplification in breast cancer implies that it has important normal functions in the mammary gland. To investigate the functions of ErbB2 during normal mouse mammary gland development, we transplanted mammary buds from genetically rescued
ErbB2
–/–
embryos that express ErbB2 in the cardiac muscle.
ErbB2
–/–
mammary buds transplanted to a wild-type mammary fat pad support outgrowth of an epithelial tree that advances only slowly through the mammary fat pad at puberty. This penetration defect is associated with structural defects in terminal end buds, characterized by a decrease in body cell number, an increased presence of cap-like cells in the prelumenal compartment, and the presence of large luminal spaces. Lobuloalveolar development was not affected in glands that developed from
ErbB2
–/–
transplanted tissue. The results may have implications for the aggressive phenotypes associated with
ERBB2
-overexpressing mammary carcinomas.
7α-Hydroxypregnenolone acts as a neuronal activator to stimulate locomotor activity of breeding newts by means of the dopaminergic system
Authors: Matsunaga Masahiro , Ukena Kazuyoshi , Baulieu Etienne-Emile , Tsutsui Kazuyoshi
Published: November 2004

It is becoming clear that steroids can be synthesizedde novoby the brain and other nervous systems. Such steroids are called neurosteroids, andde novoneurosteroidogenesis from cholesterol is a conserved property of vertebrate brains. In this study, we show that the newt brain actively produces 7α-hydroxypregnenolone, a previously undescribed amphibian neurosteroid that stimulates locomotor activity. 7α-hydroxypregnenolone was identified as a most abundant amphibian neurosteroid in the newt brain by using biochemical techniques combined with HPLC, TLC, and GC-MS analyses. The production of 7α-hydroxypregnenolone in the diencephalon and rhombencephalon was higher than that in the telencephalon and peripheral steroidogenic glands. In addition, 7α-hydroxypregnenolone synthesis in the brain showed marked changes during the annual breeding cycle, with a maximal level in the spring breeding period when locomotor activity of the newt increases. Behavioral analysis of newts in the nonbreeding period demonstrated that administration of this previously undescribed amphibian neurosteroid acutely increased locomotor activity.In vitroanalysis further revealed that 7α-hydroxypregnenolone treatment resulted in a dose-dependent increase in the release of dopamine from cultured brain tissue of nonbreeding newts. The effect of this neurosteroid on locomotion also was abolished by dopamine D2-like receptor antagonists. These results indicate that 7α-hydroxypregnenolone acts as a neuronal activator to stimulate locomotor activity of breeding newts through the dopaminergic system. This study demonstrates a physiological function of 7α-hydroxypregnenolone that has not been described previously in any vertebrate class. This study also provides findings on the regulatory mechanism of locomotor activity from a unique standpoint.
Phospholipid bilayer surface configuration probed quantitatively by
31
P field-cycling NMR
Authors: Roberts Mary F. , Redfield Alfred G.
Published: November 2004

31
P relaxation of the diester phosphate of phospholipids in unilamellar vesicles has been studied from 0.004 to 11.7 T. Relaxation at very low fields, below 0.1 T, shows a rate increase that reflects a residual dipolar interaction with neighboring protons, probably dominated by the glycerol C3 protons. This interaction is not fully averaged by faster motion such as rotational diffusion perpendicular to the membrane surface. The remaining dipolar interaction, modulated by overall rotational diffusion of the vesicle and lateral diffusion of the lipid molecules, is responsible for the very low-field relaxation. These measurements yield a good estimate of the time-average angle between the membrane surface and the vector connecting the phosphorus to the glycerol C3 protons, based on the classic theory by Woessner [Woessner, D. E. (1962)
J
.
Chem. Phys.
37
,
647–654]. Dynamic information is also obtained. Implications for solid-state NMR and other studies are discussed.
A critical role for

p27
kip1

gene dosage in a mouse model of prostate carcinogenesis
Authors: Gao Hui , Ouyang Xuesong , Banach-Petrosky Whitney , Borowsky Alexander D. , Lin Yong , Kim Minjung , Lee Hansol , Shih Weichung-Joseph , Cardiff Robert D. , Shen Michael M. , Abate-Shen Cory
Published: November 2004

In human prostate cancer, the frequent down-regulation of p27
kip1
protein expression is correlated with poor clinical outcome, yet

p27
kip1

rarely undergoes mutational inactivation. Here, we investigate the consequences of reducing or eliminating

p27
kip1

function for prostate carcinogenesis in the context of a mouse modeling lacking the
Nkx3.1
homeobox gene and the
Pten
tumor suppressor. Unexpectedly, we find that triple mutant mice heterozygous for a

p27
kip1

null allele (
Nkx3.1
+/– or –/–
;
Pten
+/–
;
p27
+/–
) display enhanced prostate carcinogenesis, whereas mice that are homozygous null for

p27
kip1

(
Nkx3.1
+/– or –/–
;
Pten
+/–
;
p27
–/–
) show inhibition of cancer progression. Expression profiling reveals that
Cyclin D1
is highly up-regulated in compound

p27
kip1

heterozygotes, but is down-regulated in the compound

p27
kip1

homozygous mutants. Using RNA interference in prostate cancer cell lines with distinct

p27
kip1

gene doses, we show that prostate tumorigenicity depends on levels of

p27
kip1

and that the consequences of

p27
kip1

gene dosage can be attributed, in part, to altered levels of Cyclin D1. Our findings suggest that

p27
kip1

possesses dosage-sensitive positive as well as negative modulatory roles in prostate cancer progression.
Functional regulatory immune responses against human cartilage glycoprotein-39 in health vs. proinflammatory responses in rheumatoid arthritis
Authors: van Bilsen Jolanda H. M. , van Dongen Henrike , Lard Leroy R. , van der Voort Ellen I. H. , Elferink Diënne G. , Bakker Aleida M. , Miltenburg André M. M. , Huizinga Tom W. J. , de Vries René R. P. , Toes René E. M.
Published: November 2004

The class of immune response against autoantigens could profoundly influence the onset and/or outcome of autoimmune diseases. Until now, there is only limited information on the antigen-specific balance between proinflammatory and regulatory responses in humans. Here we analyzed the natural immune response against a candidate autoantigen in rheumatoid arthritis, human cartilage glycoprotein-39 (HC gp-39). Peripheral blood mononuclear cells from healthy individuals reacted against HC gp-39 with the production of IL-10 but not IFN-γ.Ex vivoassays indicated that the naturally occurring HC gp-39-specific immune response in bulk is powerful enough to suppress antigen-specific recall responses, demonstrating that rather than being unresponsive, the HC gp-39-directed immune response in healthy individuals shows a strong bias toward a regulatory phenotype. Moreover, CD4+T cell lines directed against HC gp-39 expressed CD25, glucocorticoid-induced tumor necrosis factor receptor, and Foxp3 molecules and were capable of suppressing antigen-specific T cell responses. Cell–cell contact was required for this suppression. As opposed to healthy individuals, the HC gp-39-directed immune response in 50% of patients with rheumatoid arthritis exhibits polarization toward a proinflammatory T helper 1 phenotype and is significantly less powerful in suppressing antigen-specific recall responses. Together these findings indicate that the presence of HC gp-39-specific immune responses in healthy individuals may have an inhibitory effect on inflammatory responses in areas where HC gp-39 is present. Furthermore, these data indicate that the class of HC gp-39-directed immune response in rheumatoid arthritis patients has shifted from an antiinflammatory toward a proinflammatory phenotype.
EST-based genome-wide gene inactivation identifies ARAP3 as a host protein affecting cellular susceptibility to anthrax toxin
Authors: Lu Quan , Wei Wensheng , Kowalski Paul E. , Chang Annie C. Y. , Cohen Stanley N.
Published: November 2004

The lethality of infection by
Bacillus anthracis
is largely due to its plasmid-encoded toxins, which consist of a carrier protein, the protective antigen (PA), in combination with either the lethal-factor or edema-factor moiety. During
B. anthracis
infections, PA secreted by bacteria binds to membrane receptors of susceptible cells, is cleaved proteolytically, attaches to lethal factor or edema factor, undergoes oligomerization and internalization, and transports its toxin partners to acidic endosomes where they are released into the cytosol. To identify specific host functions that mediate these events, we used RNA encoded by a lentivirus-based library of ≈40,000 human ESTs to inactivate chromosomal genes in a human cell population, and we isolated clones that survived PA-dependent toxin-induced death. This phenotypic screen and subsequent analysis identified ARAP3, which is a phosphoinositide-binding protein implicated previously in membrane vesicle trafficking and cytoskeletal organization, as a mammalian host-cell gene that is essential for normal anthrax toxicity. ARAP3 deficiency produced by antisense expression of an ARAP3 EST impaired entry of PA and its bound toxigenic moieties into both human and mouse cells, resulting in reduced toxin sensitivity. Our results demonstrate the usefulness of antisense EST libraries for global chromosomal gene inactivation, establish the practicality of loss-of-function phenotypic screens for the identification of genomic loci required for pathogen effects in mammalian cells, and reveal an important role for ARAP3 in cellular internalization of anthrax toxin.
‘TRIPs‐plus’ patent privileges—an intellectual property ‘Cargo cult’ in Australia
Authors: LAWSON CHARLES , PICKERING CATHERINE
Published: November 2004

This article challenges the desirability of implementing more than the minimum patent standards required by Australia’s commitment to the World Trade Organisation’s Agreement on Trade Related Aspects of Intellectual Property Rights (so‐called ‘TRIPs‐plus’ measures). We argue that there has not been an adequate analysis of what the various TRIPs‐plus measures actually are under the Patents Act 1990 (Cth), and that these measures have not been subjected to a competition analysis as required by the Competition Principles Agreement. This is, we contend, reminiscent of ‘cargo cult’ as Australian policy makers appear to reason that the most developed nations have benefited from innovation with TRIPs‐plus measures, and so with similar measures, those same benefits will accrue to Australia.
Beyond broadcasting: the digital future of public service broadcasting
Authors: ARIÑO MÓNICA , AHLERT CHRISTIAN
Published: November 2004

This article looks at the impact of digitization on television. Early treatments of digital television (DTV) have become outdated by technical and market developments. This paper reviews these developments and reconsiders the public policy and regulatory issues surrounding DTV, particularly with respect to public service broadcasting in Europe. Convergence trends are examined and we find that it happens, but differently than expected. This raises serious doubts concerning whether current models and conceptualizations of public service broadcasting can address future challenges of pluralism and diversity if they remain constrained by traditional understandings of broadcasting.
Models of co‐occurring substance misuse and psychosis: are personality traits the missing link?
Authors: HIDES LEANNE , LUBMAN DAN I. , DAWE SHARON
Published: November 2004

Traditional models of co‐occurring substance misuse in psychosis, including the vulnerability and coping (self‐medication) hypotheses, have tended to focus on state‐specific factors, such as the severity of substance misuse or psychotic symptoms. In contrast, more recent personality models posit that co‐morbidity is related to individual differences in stable trait‐specific personality variables that underlie affective outcomes, coping strategies and subsequent risk for substance use. This paper reviews the current evidence base for these three models, and suggests that future research examine the inter‐relationships between trait and state‐specific personality, affective and behavioural variables on co‐morbidity.
Cannabis use and psychotic disorders: an update
Authors: HALL WAYNE , DEGENHARDT LOUISA , TEESSON MAREE
Published: November 2004

This paper evaluates three hypotheses about the relationship between cannabis use and psychosis in the light of recent evidence from prospective epidemiological studies. These are that: (1) cannabis use causes a psychotic disorder that would not have occurred in the absence of cannabis use; (2) that cannabis use may precipitate schizophrenia or exacerbate its symptoms; and (3) that cannabis use may exacerbate the symptoms of psychosis. There is limited support for the first hypothesis. As a consequence of recent prospective studies, there is now stronger support for the second hypothesis. Four recent prospective studies in three countries have found relationships between the frequency with which cannabis had been used and the risk of receiving a diagnosis of schizophrenia or of reporting psychotic symptoms. These relationships are stronger in people with a history of psychotic symptoms and they have persisted after adjustment for potentially confounding variables. The absence of any change in the incidence of schizophrenia during the three decades in which cannabis use in Australia has increased makes it unlikely that cannabis use can produce psychoses that would not have occurred in its absence. It seems more likely that cannabis use can precipitate schizophrenia in vulnerable individuals. There is also reasonable evidence for the third hypothesis that cannabis use exacerbates psychosis.
A review of research on residential programs for people with severe mental illness and co‐occurring substance use disorders
Authors: BRUNETTE MARY F. , MUESER KIM T. , DRAKE ROBERT E.
Published: November 2004

Substance use disorder is the most common and clinically significant co‐morbidity among clients with severe mental illnesses, associated with poor treatment response, homelessness and other adverse outcomes. Residential programs for clients with dual disorders integrate mental health treatment, substance abuse interventions, housing and other supports. Ten controlled studies suggest that greater levels of integration of substance abuse and mental health services are more effective than less integration. Because the research is limited by methodological problems, further research is needed to establish the effectiveness of residential programs, to characterize important program elements, to establish methods to improve engagement into and retention in residential programs and to clarify which clients benefit from this type of service.
Quantitative Drug Levels in Stimulant Psychosis: Relationship to Symptom Severity, Catecholamines and Hyperkinesia
Authors: Batki Steven L. , Harris Debra S.
Published: November 2004

To examine the relationship between quantitative stimulant drug levels, catecholamines, and psychotic symptoms, nineteen patients in a psychiatric emergency service with a diagnosis of amphetamine‐ or cocaine‐induced psychosis were interviewed, and plasma and urine were collected for quantitative assays of stimulant drug and catecholamine metabolite levels. Methamphetamine or amphetamine levels were related to several psychopathology scores and the global hyperkinesia rating. HVA levels were related to global hyperkinesia but not to psychopathology ratings. Although many other factors such as sensitization may play a role, intensity of stimulant‐induced psychotic symptoms and stereotypies appears to be at least in part dose‐related.