bluuebunny/crossref_metadata_2025 huggingface dataset:
Extrapolation methods for improving convergence of spherical Bessel integrals for the two‐center Coulomb integrals
Authors: Safouhi Hassan , Bouferguene Ahmed
Published: April 2006

Multi‐center two‐electron Coulomb integrals over Slater‐type functions are required for any accurate molecular electronic structure calculations. These integrals, which are numerous, are to be evaluated rapidly and accurately. Slater‐type functions are expressed in terms of the so‐called B functions, which are best suited to apply the Fourier transform method. The Fourier transform method allowed analytic expressions for these integrals to be developed. Unfortunately, the analytic expressions obtained turned out to be extremely difficult to evaluate accurately due to the presence of highly oscillatory spherical Bessel integrals. In this work, we used techniques based on nonlinear transformation and extrapolation methods for improving convergence of these oscillatory spherical Bessel integrals. These techniques, which led to highly efficient and rapid algorithms for the numerical evaluation of three‐ and four‐center two‐electron Coulomb and exchange integrals, are now shown to be applicable to the two‐center two‐electron Coulomb integrals. The numerical results obtained for the molecular integrals under consideration illustrate the efficiency of the algorithm described in the present work compared with algorithms using the epsilon (ε) algorithm of Wynn and Levin's u transform. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Genetic and environmental sources of egg size, fecundity and body size in the migrant skipper, Parnara guttata guttata (Lepidoptera: Hesperiidae)
Authors: Seko Tomokazu , Miyatake Takahisa , Fujioka Shinsuke , Nakasuji Fusao
Published: April 2006

Genetic and environmental sources of egg size, fecundity and body size (forewing length) were examined in the butterfly, Parnara guttata guttata. Phenotypic and genetic correlation and heritability were estimated for these traits under different day‐length and temperature conditions. Egg size and fecundity had relatively high heritabilities, and body sizes in males and females had moderate and high heritability, respectively. Negative phenotypic and genetic correlations between egg size and fecundity were estimated in treatments corresponding to the natural conditions during larval development of the first and second generations. Phenotypic and genetic correlations between body size and egg size differed considerably between insects reared under long and short day‐lengths. Next, genotype–environment interactions were estimated by comparing reaction norms to day‐length or temperature of these traits among families. ANOVA analysis revealed significant genotype–environment interactions in egg size and forewing length in both sexes for day‐length and temperature. These results suggested that a large additive genetic variance for egg size might have been maintained by a genetic trade‐off and/or by genotype–environment interactions in P. g. guttata.
The E3 ubiquitin ligase HOIL‐1 induces the polyubiquitination and degradation of SOCS6 associated proteins
Authors: Bayle Julie , Lopez Sophie , Iwaï Kazuhiro , Dubreuil Patrice , De Sepulveda Paulo
Published: April 2006

The suppressor of cytokine signaling (SOCS) proteins are thought to exert their function through the recruitment of interacting‐proteins to the ubiquitin/proteasome degradation pathway. All SOCS proteins bind an Elongin BC E3 ubiquitin ligase complex through the common Socs‐box. Here, we show that haem‐oxidized IRP2 ubiquitin ligase‐1 (HOIL‐1), another E3 ubiquitin ligase, interacts with SOCS6. The Ubl domain of HOIL‐1 and the SH2 and Socs‐box domains of SOCS6 are required for the interaction. HOIL‐1 expression stabilizes SOCS6 and induces the ubiquitination and degradation of proteins associated with SOCS6. These data suggest that SOCS proteins may interact with different E3 ubiquitin ligases in addition to a common Elongin BC E3 complex.
The Swi/Snf chromatin remodeling complex is essential for hyphal development in Candida albicans
Authors: Mao Xuming , Cao Fang , Nie Xinyi , Liu Haoping , Chen Jiangye
Published: April 2006

The ability of dimorphic transition between yeast and hyphal forms in Candida albicans is one of the vital determinants for its pathogenicity and virulence. We isolated C. albicans SWI1 as a suppressor of the invasive growth defect in a Saccharomyces cerevisiae mutant. Expression of C. albicans SWI1 in S. cerevisiae partially complemented the growth defect of a swi1 mutant in the utilization of glycerol. Swi1 is in a complex with Snf2 in C. albicans, and both proteins are localized in the nucleus independent of the growth form. Deleting SWI1 or SNF2 in C. albicans prevented true hyphal formation and resulted in constitutive pseudohypha‐like growth in all media examined. Furthermore, swi1/swi1 mutant was defective in hypha‐specific gene expression and avirulent in a mouse model of systemic infection. These data strongly suggest the conserved Swi/Snf complex in C. albicans is required for hyphal development and pathogenicity.
MELDB: A database for microbial esterases and lipases
Authors: Kang Ho-Young , Kim Jihyun F. , Kim Myung Hee , Park Seung-Hwan , Oh Tae-Kwang , Hur Cheol-Goo
Published: April 2006

MELDB is a comprehensive protein database of microbial esterases and lipases which are hydrolytic enzymes important in the modern industry. Proteins in MELDB are clustered into groups according to their sequence similarities based on a local pairwise alignment algorithm and a graph clustering algorithm (TribeMCL). This differs from traditional approaches that use global pairwise alignment and joining methods. Our procedure was able to reduce the noise caused by dubious alignment in the distantly related or unrelated regions in the sequences. In the database, 883 esterase and lipase sequences derived from microbial sources are deposited and conserved parts of each protein are identified. HMM profiles of each cluster were generated to classify unknown sequences. Contents of the database can be keyword‐searched and query sequences can be aligned to sequence profiles and sequences themselves.
U/Th age constraints on the absence of ice in the central Inn Valley (eastern Alps, Austria) during Marine Isotope Stages 5c to 5a
Authors: Spötl Christoph , Mangini Augusto
Published: April 2006

Calcitic flowstones are present in fractures of a Pleistocene breccia near Innsbruck, Austria, and record periods of carbonate precipitation in the unsaturated zone between 101,500 ± 1500 and 70,300 ± 1800 yr, constrained by U-series disequilibrium dates. The occurrence of these speleothems, their low carbon isotopic composition, and the lack of infiltrated siliciclastic material demonstrate that the central Inn valley – which harbored one of the most extensive valley glaciers during the last glacial maximum – was ice-free during Marine Isotope Stages 5c to 5a. Climatically warm periods are separated by distinct drops in the oxygen isotopic composition of the speleothem calcite, attributed to strong and possibly seasonally biased atmospheric cooling. During these intervening stadials, which mirror those identified in the Greenland ice cores and marine sea-surface temperature records, calcite deposition apparently came to a halt, but the Inn Valley remained ice-free. The youngest calcite layer formed between ∼74,000 and ∼70,000 yr and places a maximum age limit on the likely expansion of alpine glaciers during the Marine Isotope Stage 5/4 transition, consistent with other speleothem records.
Immunolocalization of metabotropic glutamate receptors 1 and 5 in the synaptic layers of the chicken retina
Authors: SEN MADHUMITA , GLEASON EVANNA
Published: April 2006

We have examined the distribution of metabotropic glutamate receptors (mGluRs) 1 and 5 in the adult chicken retina using preembedding immuno-electronmicroscopy. Immunoreactivity for mGluRs 1 and 5 was found in both the outer plexiform layer (OPL) and the inner plexiform layer (IPL). For mGluR1, OPL labeling was observed at cone pedicles and horizontal and bipolar cell processes. In the IPL, mGluR1 labeling could be found on bipolar cell terminals, as well as postsynaptic processes, including amacrine cell processes. Neither presynaptic nor postsynaptic elements were labeled at rod synapses. For mGluR5, OPL labeling was associated with cone pedicles as well as bipolar and horizontal cell processes. As for mGluR1, rod synapses were unlabeled. In the IPL, labeling for mGluR5 was found on bipolar cell terminals and amacrine cell processes. The presynaptic expression of these receptors in the OPL was confirmed at the light level by double-labeling experiments with SV2. The distributions of mGluRs 1 and 5 indicate that they have the potential to regulate function in both synaptic layers. Furthermore, the similar expression patterns for these two receptors indicate that they might be co-expressed and thus have the potential to interact functionally.
ROUSSEAU'S “PEUT-ETRE”: REFLECTIONS ON THE STATUS OF THE STATE OF NATURE
Authors: KELLY CHRISTOPHER
Published: April 2006

In the Confessions Rousseau provides a very helpful account of the composition of the Discourse on Inequality (as he calls the Second Discourse). This account contains two elements that prefigure the work's reputation among scholars today. First, Rousseau says that, while in his earlier works he had only partially revealed the basis of his thought, the question posed by the Academy of Dijon offered him the occasion to develop his principles, “completely in a work of the greatest importance.” A few pages later he confirms the importance of the Discourse by saying, “Everything that is bold in the Social Contract was previously in the Discourse on Inequality.” A consensus of scholars would, I think, agree that the Discourse is, indeed, a particularly bold work and the first place to look for a rigorous exposition of Rousseau's principles.
Effects of Short-Term Supplementation with Ascorbate, Folate, and Vitamins B6 and B12 on Inflammatory Factors and Estrogen Levels in Obese Postmenopausal Women
Authors: Palmas Walter
Published: April 2006

Little is known about the effects of commonly used vitamins on serum inflammatory markers and the hormonal balance in obese postmenopausal women. We studied the effects of an 8-week open-label supplementation with vitamins C (500 mg), B6 (25 mg), B12 (1 mg), and folate (5 mg) on C-reactive protein, interleukin-6, and estradiol levels in 20 obese (body mass index ≥ 30) postmenopausal women. Outcomes were assessed in a blinded fashion. Folate and vitamin B12 levels rose significantly, suggesting that the supplement was well absorbed and that participants adhered to the protocol. Weight, blood pressure, and serum lipids remained stable. C-reactive protein, interleukin-6, and leptin levels remained unchanged. Estradiol levels rose from a median of 22.0 pg/mL (IQR = 15.9–25.8) at baseline to a median of 27.8 pg/mL (IQR = 23.1–33.9) at follow-up (p = 0.003). Increments in serum estradiol caused by vitamin supplementation in postmenopausal women have not been previously described and probably merit further investigation.
Selbstkontrolle als Arbeitsanforderung - Rekonzeptualisierung und Validierung eines Messinstruments
Authors: Neubach Barbara , Schmidt Klaus-Helmut
Published: April 2006

Zusammenfassung. An immer mehr Arbeitsplätzen wird heute ein kontrolliertes und zielorientiertes Verhalten von den Beschäftigten erwartet: Betrieblicherseits gefordertes Verhalten soll gezeigt und gleichzeitig spontanes Verhalten unterdrückt werden. Ergebnisse aus der Grundlagenforschung lassen vermuten, dass ein derart kontrolliertes Verhalten mit psychischen Kosten verbunden ist. In der Arbeits- und Organisationspsychologie ist über die Auswirkungen tätigkeitsbedingter Selbstkontrolle bislang wenig bekannt. Die hier vorgestellten Skalen geforderte Selbstkontrolle bei der Arbeit und erlebte emotionale Dissonanz ermöglichen eine Berücksichtigung dieser Anforderungen in der arbeitspsychologischen Forschung. Die Analysen zeigen, dass geforderte Selbstkontrolle und emotionale Dissonanz faktoriell distinkte und nur mäßig korrelierte Konstrukte abbilden. Beide Maße weisen zudem bedeutsame Zusammenhänge mit Beanspruchungsmaßen und Fehlzeiten im Jahr nach der Untersuchung auf.
Initiation of localized shear zones in viscoelastoplastic rocks
Authors: Kaus Boris J. P. , Podladchikov Yuri Y.
Published: April 2006

Shear localization is a process of primary importance for the onset of subduction and the evolution of plate tectonics on Earth. In this paper we focus on a model in which shear localization is initiated through shear heating. The rheology employed is linear Maxwell viscoelastic with von Mises plasticity and an exponential dependence of viscosity on temperature. Dimensional analysis reveals that four nondimensional (0‐D) parameters control the initiation of shear zones. The onset of shear localization is systematically studied with 0‐D, 1‐D, and 2‐D numerical models, both under constant stress and under constant velocity boundary conditions. Mechanical phase diagrams demonstrate that six deformation modes exist under constant velocity boundary conditions. A constant stress boundary condition, on the other hand, exhibits only two deformation modes (localization or no localization). Scaling laws for the growth rate of temperature are computed for all deformation modes. Numerical and analytical solutions demonstrate that diffusion of heat may inhibit localization. Initial heterogeneities are required to initiate localization. The derived scaling laws are applied to Earth‐like parameters. For a given heterogeneity size, stable (nonseismic) localization only occurs for a certain range of effective viscosities. Localization is inhibited if viscosity is smaller then a minimum threshold, which is a function of the heterogeneity size. The simplified rheological model is compared with a more realistic and more complex model of olivine that takes diffusion, power law, and Peierls creep into account. Good agreement exists between the models. The simplified model proposed in this study thus reproduces the main physics of ductile faulting. Two‐dimensional late stage simulations of lithospheric‐scale shear localization are presented that confirm the findings of the initial stage analysis.
Spatial heterogeneity of near‐bed hydraulics above a patch of river gravel
Authors: Buffin‐Bélanger Thomas , Rice Stephen , Reid Ian , Lancaster Jill
Published: April 2006

The spatial heterogeneity of fully turbulent, near‐bed flows above gravel river beds is examined using a realistic replica of a natural gravel patch in a large flume. Three‐dimensional velocity time series were obtained at four heights (0.008–0.1 m) above the local bed in each of 99 closely spaced verticals for three flows of increasing intensity. The spatial heterogeneity of time‐averaged velocities and root‐mean‐square velocity fluctuations increases under stronger flows and closer to the bed. However, streamwise velocity becomes spatially homogeneous at a distance from the bed of between 2–4 times the median bed elevation. Heterogeneity in the direction of the velocity vector is independent of mean flow velocity, but in all cases it decreases approximately linearly with distance above the surface. Skewness of the instantaneous velocity distributions suggests that slowly moving fluid emanating from the near‐bed region impinges upon higher levels with greater frequency and greater spatial coverage as the average flow velocity increases. Spatial heterogeneity in turbulent kinetic energy increases with flow velocity and maxima occurr at positions that intercept layers of intense vortex shedding in the lee of obstacle crests. The spatial organization of the flow properties is nonrandom and consistent across the three flows. Simple regression models are developed to provide a basis for investigating the heterogeneity of near‐bed flow at the patch scale (∼2 m2) in gravel bed rivers.
A stochastic model of nitrate transport and cycling at basin scale
Authors: Botter Gianluca , Settin Tommaso , Marani Marco , Rinaldo Andrea
Published: April 2006

A stochastic framework for modelling catchment‐scale hydrologic and nitrate responses (as a byproduct of transport processes and of a biogeochemical model of nitrogen cycling and transformations in heterogeneous soils) is proposed and applied to a 53 km2 basin in northeastern Italy, where observational data and complex land‐use distribution and geomorphology demand suitable descriptions. The model is based on a geomorphological scheme of the hydrologic response coupled with suitable Lagrangian transport models (mass‐response functions) applied in a Montecarlo framework which explicitly addresses the random character of the processes controlling nitrate generation to the hydrologic cycle, and its transformations and transport. This is obtained by coupling the stochastic generation of climatic and rainfall series with the hydrologic and biogeochemical models. Special attention is devoted to the spatial and temporal variability of nitrogen sources of agricultural origin and to the effects of the relative timing and intensity of the forcing rainfall fields on the ensuing nitrate leaching. The influence of random climatic variables on biogeochemical processes affecting the nitrogen cycle in the soil‐water system (e.g., plant uptake, nitrification and denitrification, mineralization) is also considered. Besides its conceptual interest, the relevance of the model stems from the capabilities of estimating the return period of nitrate loads to the receiving water body and the probability distribution of the variables computed. We found that the modes of nitrogen injection through fertilization significantly affect the form of probability distribution of nitrate contained in soil moisture even when the total amount is fixed. As a result, the return period of the water volumes discharged and of the nitrate loads released (in this case into the Venice lagoon) can be linked directly to the ongoing climatic and agricultural regimes, with implications for sustainable management practices.
Solar activity reconstructed over the last 7000 years: The influence of geomagnetic field changes
Authors: Usoskin I. G. , Solanki S. K. , Korte M.
Published: April 2006

The long‐term solar activity, as manifested by sunspot number, has been recently reconstructed on multi‐millennium time scales by S. K. Solanki et al. (2004) from the measured concentration of 14C in tree rings. The exact level of the reconstructed solar activity depends, however, on independently evaluated data of the geomagnetic dipole strength variations. Recently, a new series of the palaeomagnetic dipole moment reconstruction for the last 7000 years has been presented by M. Korte and C. G. Constable (2005a) on the basis of a thorough analysis of global samples. The new palaeomagnetic series yields a systematically lower dipole moment in the past, compared to the earlier geomagnetic reconstructions. We have revised the earlier sunspot activity reconstruction since 5000 BC, using the new geomagnetic data series, and found that it is roughly consistent with the previous results during most of the period, although the revised sunspot number values are in general higher. Nonetheless, it is confirmed with the new palaeomagnetic series that the Sun spends only 2–3% of the time in a state of high activity, similar to the modern episode. This strengthens the conclusion that the modern high activity level is very unusual during the last 7000 years.
Methane hydrate formation and decomposition: Structural studies via neutron diffraction and empirical potential structure refinement
Authors: Thompson Helen , Soper Alan K. , Buchanan Piers , Aldiwan Nawaf , Creek Jefferson L. , Koh Carolyn A.
Published: April 2006

Neutron diffraction studies with hydrogen/deuterium isotope substitution measurements are performed to investigate the water structure at the early, medium, and late periods of methane clathrate hydrate formation and decomposition. These measurements are coupled with simultaneous gas consumption measurements to track the formation of methane hydrate from a gas/water mixture, and then the complete decomposition of hydrate. Empirical potential structure refinement computer simulations are used to analyze the neutron diffraction data and extract from the data the water structure in the bulk methane hydrate solution. The results highlight the significant changes in the water structure of the remaining liquid at various stages of hydrate formation and decomposition, and give further insight into the way in which hydrates form. The results also have important implications on the memory effect, suggesting that the water structure in the presence of hydrate crystallites is significantly different at equivalent stages of forming compared to decomposing. These results are in sharp contrast to the previously reported cases when all remaining hydrate crystallites are absent from the solution. For these systems there is no detectable change in the water structure or the methane hydration shell before hydrate formation and after decomposition. Based on the new results presented in this paper, it is clear that the local water structure is affected by the presence of hydrate crystallites, which may in turn be responsible for the “history” or “memory” effect where the production of hydrate from a solution of formed and then subsequently melted hydrate is reportedly much quicker than producing hydrate from a fresh water/gas mixture.
Structure and stability of xenon insertion compounds of hypohalous acids, HXeOX [X=F, Cl, and Br]: An ab initio investigation
Authors: Jayasekharan T. , Ghanty T. K.
Published: April 2006

The structure and stability of xenon-inserted hypohalous acids HXeOX (X=F, Cl, and Br) have been investigated theoretically using ab initio molecular orbital calculations. All these molecules are found to consist of a nearly linear HXeO moiety and a bend XeOX fragment. Geometrical parameters of HXeOX are comparable with that of experimentally observed HXeOH species. The dissociation energies corresponding to the lowest-energy fragmentation products, HOX+Xe have been computed to be −398.1, −385.5, and −386.7kJ∕mol for HXeOF, HXeOCl, and HXeOBr, respectively, at the MP2 level of theory. The respective barrier heights corresponding to the bent transition states (H–Xe–O bending mode) have been calculated to be 138.1, 138.4, and 138.2kJ∕mol with respect to HXeOX minimum. These species are found to be metastable in their respective potential-energy surface, and the dissociation energies corresponding to the H+Xe+OX products are found to be 56.8, 66.0, and 80.8kJ∕mol for HXeOF, HXeOCl, and HXeOBr, respectively. The energies corresponding to the H+Xe+O+X dissociation channel have been computed to be 272.0, 309.3, and 299.7kJ∕mol for HXeOF, HXeOCl, and HXeOBr, respectively, at the same level of theory. Energetics as well as geometrical considerations suggests that it may be possible to prepare these species experimentally similar to that of HXeOH species at low-temperature laser photolysis experiments.
Pattern transitions on Ge surfaces during low-energy ion beam erosion
Authors: Ziberi B. , Frost F. , Rauschenbach B.
Published: April 2006

During sputtering of Ge surfaces with Xe+ ions at 2keV ion energy at room temperature, self-organized ripple and dot nanostructures with a mean wavelength below 60nm emerge as the ion incidence angle is varied. Dots evolving at normal ion incidence pass into ripple patterns with increasing ion incidence angle. Furthermore, for ion incidence angles above 10deg to the surface normal a gradual transition from ripples to dots is observed. Guided by the previous existence of ripples these evolving dot patterns show a long range hexagonal ordering extending across the whole sample surface.
A carbohydrate-binding protein, Galectin-1, promotes proliferation of adult neural stem cells
Authors: Sakaguchi Masanori , Shingo Tetsuro , Shimazaki Takuya , Okano Hirotaka James , Shiwa Mieko , Ishibashi Satoru , Oguro Hideyuki , Ninomiya Mikiko , Kadoya Toshihiko , Horie Hidenori , Shibuya Akira , Mizusawa Hidehiro , Poirier Françoise , Nakauchi Hiromitsu , Sawamoto Kazunobu , Okano Hideyuki
Published: April 2006

In the subventricular zone of the adult mammalian forebrain, neural stem cells (NSCs) reside and proliferate to generate young neurons. We screened factors that promoted the proliferation of NSCs
in vitro
by a recently developed proteomics technique, the ProteinChip system. In this screen, we identified a soluble carbohydrate-binding protein, Galectin-1, as a candidate. We show herein that Galectin-1 is expressed in a subset of slowly dividing subventricular zone astrocytes, which includes the NSCs. Based on results from intraventricular infusion experiments and phenotypic analyses of knockout mice, we demonstrate that Galectin-1 is an endogenous factor that promotes the proliferation of NSCs in the adult brain.
A neuropeptide Y Y5 antagonist selectively ameliorates body weight gain and associated parameters in diet-induced obese mice
Authors: Ishihara Akane , Kanatani Akio , Mashiko Satoshi , Tanaka Takeshi , Hidaka Masayasu , Gomori Akira , Iwaasa Hisashi , Murai Naomi , Egashira Shin-ichiro , Murai Takashi , Mitobe Yuko , Matsushita Hiroko , Okamoto Osamu , Sato Nagaaki , Jitsuoka Makoto , Fukuroda Takahiro , Ohe Tomoyuki , Guan Xiaoming , MacNeil Douglas J. , Van der Ploeg Lex H. T. , Nishikibe Masaru , Ishii Yasuyuki , Ihara Masaki , Fukami Takehiro
Published: April 2006

Neuropeptide Y (NPY) is thought to have a major role in the physiological control of energy homeostasis. Among five NPY receptors described, the NPY Y5 receptor (Y5R) is a prime candidate to mediate some of the effects of NPY on energy homeostasis, although its role in physiologically relevant rodent obesity models remains poorly defined. We examined the effect of a potent and highly selective Y5R antagonist in rodent obesity and dietary models. The Y5R antagonist selectively ameliorated diet-induced obesity (DIO) in rodents by suppressing body weight gain and adiposity while improving the DIO-associated hyperinsulinemia. The compound did not affect the body weight of lean mice fed a regular diet or genetically obese leptin receptor-deficient mice or rats, despite similarly high brain Y5R receptor occupancy. The Y5R antagonist acts in a mechanism-based manner, as the compound did not affect DIO of Y5R-deficient mice. These results indicate that Y5R is involved in the regulation and development of DIO and suggest utility for Y5R antagonists in the treatment of obesity.
Desensitization of mechano-gated K
2P
channels
Authors: Honoré Eric , Patel Amanda Jane , Chemin Jean , Suchyna Thomas , Sachs Frederick
Published: April 2006

The neuronal mechano-gated K
2P
channels TREK-1 and TRAAK show pronounced desensitization within 100 ms of membrane stretch. Desensitization persists in the presence of cytoskeleton disrupting agents, upon patch excision, and when channels are expressed in membrane blebs. Mechanosensitive currents evoked with a variety of complex stimulus protocols were globally fit to a four-state cyclic kinetic model in detailed balance, without the need to introduce adaptation of the stimulus. However, we show that patch stress can be a complex function of time and stimulation history. The kinetic model couples desensitization to activation, so that gentle conditioning stimuli do not cause desensitization. Prestressing the channels with pressure, amphipaths, intracellular acidosis, or the E306A mutation reduces the peak-to-steady-state ratio by changing the preexponential terms of the rate constants, increasing the steady-state current amplitude. The mechanical responsivity can be accounted for by a change of in-plane area of ≈2 nm
2
between the closed and open conformations. Desensitization and its regulation by chemical messengers is predicted to condition the physiological role of K
2P
channels.
An electronic time scale in chemistry
Authors: Remacle F. , Levine R. D.
Published: April 2006

Ultrafast, subfemtosecond charge migration in small peptides is discussed on the basis of computational studies and compared with the selective bond dissociation after ionization as observed by Schlag and Weinkauf. The reported relaxation could be probed in real time if the removal of an electron could be achieved on the attosecond time scale. Then the mean field seen by an electron would be changing rapidly enough to initiate the migration. Tyrosine-terminated tetrapeptides have a particularly fast charge migration where in <1 fs the charge arrives at the other end. A femtosecond pulse can be used to observe the somewhat slower relaxation induced by correlation between electrons of different spins. A slower relaxation also is indicated when removing a deeper-lying valence electron. When a chromophoric amino acid is at one end of the peptide, the charge can migrate all along the peptide backbone up to the N end, but site-selective ionization is probably easier to detect for tryptophan than for tyrosine.
Immune dysregulation accelerates atherosclerosis and modulates plaque composition in systemic lupus erythematosus
Authors: Stanic Aleksandar K. , Stein Charles M. , Morgan Adam C. , Fazio Sergio , Linton MacRae F. , Wakeland Edward K. , Olsen Nancy J. , Major Amy S.
Published: April 2006

Patients with systemic lupus erythematosus (SLE) have accelerated atherosclerosis. The underlying mechanisms are poorly understood, and investigations have been hampered by the absence of animal models that reflect the human condition of generalized atherosclerosis and lupus. We addressed this problem by transferring lupus susceptibility to low-density lipoprotein (LDL) receptor-deficient (LDLr−/−) mice, an established model of atherosclerosis, creating radiation chimeras with NZM2410-derived, lupus-susceptible, B6.Sle1.2.3congenic or C57BL/6 control donors (LDLr.Sleand LDLr.B6, respectively). LDLr.Slemice developed a lupus-like disease characterized by production of double-stranded DNA autoantibodies and renal disease. When fed a Western-type diet, LDLr.Slechimeras had increased mortality and atherosclerotic lesions. The plaques of LDLr.Slemice were highly inflammatory and contained more CD3+T cells than controls. LDLr.Slemice also had increased activation of CD4+T and B cells and significantly higher antibody to oxidized LDL and cardiolipin. Collectively, these studies demonstrate that the lupus-susceptible immune system enhances atherogenesis and modulates plaque composition.
Fetal and perinatal risk factors for inflammatory bowel disease
Authors: Aspberg Sara , Dahlquist Gisela , Kahan Thomas , Källén Bengt
Published: April 2006

Aim: To study the influence of specific factors and events during pregnancy and the perinatal period on the risk of children developing inflammatory bowel disease. Methods: Population‐based national register study. Linkage between the Swedish Medical Birth Register and the Swedish Hospital Discharge Register during the period 1987 to 2000 identified 455 singleton infants who later developed inflammatory bowel disease. Data for these children were compared with data for all children born in Sweden during the same period. Results: Smoking during early pregnancy reduced the risk of inflammatory bowel disease (odds ratio (OR) 0.71, 95% CI 0.55–0.91). For ulcerative colitis the odds ratio was 0.70 (95% CI 0.56–0.86), and for Crohn's disease 0.73 (95% CI 0.58–0.94). Infections during the neonatal period seemed to increase the risk of inflammatory bowel disease (OR 17.6, 95% CI 3.6–51.6), but the number of observed events was small. The other factors examined did not influence the risk of inflammatory bowel disease.

Conclusion: Maternal smoking during early pregnancy reduces the risk for the child to be hospitalized with a diagnosis of inflammatory bowel disease. Severe neonatal infections may increase the risk. Thus, some exposures during the fetal and neonatal period seem to affect the risk of inflammatory bowel disease later in life.
Physical outcome and school performance of very‐low‐birthweight infants treated with minimal handling and early nasal CPAP
Authors: Dahl Marianne , Kamper Jens
Published: April 2006

Aim: To describe physical outcome and school performance in a cohort of very‐low‐birthweight infants treated with early nasal continuous positive airway pressure (NCPAP)/minimal handling regimen with permissive hypercapnia, in comparison to siblings of normal birthweight. Material and methods: Neonatal and follow‐up data from 213 very‐low‐birthweight infants from 1983–1988 were registered and a questionnaire concerning school achievements was sent to the families of survivors and siblings attending school. Results: Mortality was 22%. Of the survivors, 4% had moderate–severe and 9% mild sequelae. Eighty‐seven per cent of VLBW children and 95% of their siblings attended regular school. Average or above‐average achievement was accomplished by 33 (65%) of the VLBW children and 34 (74%) of the siblings in mathematics, and 35 (69%) and 32 (68%), respectively, in reading/spelling. None of these differences reached statistical significance. However, the performance ratings correlated significantly with socio‐economic conditions.

Conclusion: In this study of infants treated with a regimen of early NCPAP/minimal handling, we found a relatively low incidence of handicaps and impairments. Nearly 90% attended ordinary schools, with near‐average performances in mathematics and reading/spelling, which were not statistically different to their siblings. The overall results indicate that these infants fare at least as well as survivors after conventional treatment.
Glucose intolerance and insulin resistance in extremely premature newborns, and implications for nutritional management
Authors: YEUNG MELINDA Y.
Published: April 2006

Glucose intolerance and postnatal growth retardation are commonly seen in low‐gestation newborns. In contrast to the nutrient compositions of parenteral and enteral nutrition, fetuses at equivalent gestational ages receive much more amino acids (protein) but less glucose and lipids through placental transfer.

Conclusion: A nutrition regime that simulates placental nutrient delivery would potentially minimize glucose intolerance and facilitate early attainment of normal growth velocity with normal body composition after preterm birth.
Sensory and affective components of pain as recorded with the Pain‐O‐Meter (POM) among children with acute and chronic pain
Authors: Jylli Leena , Broström Eva , Hagelberg Stefan , Stenström Christina H. , Olsson Gunnar L. , Langius‐Eklöf Ann
Published: April 2006

Aim: To explore the usefulness of the Pain‐O‐Meter sensory and affective words scale (POM‐WDS) with regard to whether children aged 6–16 who suffer from chronic and acute pain know the words and what words they chose to describe their pain. Methods: Sixty‐one children participated, mean age 11 y, suffering from acute pain (n=25) and pain associated with juvenile idiopathic arthritis (JIA, n=36). Children rated their pain intensity on the POM‐VAS (visual analogue scale, 0–10 cm). Thereafter, children were asked whether each sensory and affective word on the POM‐WDS was known to them, and whether each word described their pain experience. Results: Seventeen out of 23 words were known to at least 70% of the sample. The least recognized word was grinding. Children age 6–16 knew fewer words than the adolescents. Age was a significant determinant for whether the children knew the words grinding (odds ratio (OR) 20.08, p<0.01), gnawing (OR 5.92, p < 0.05), unbearable (OR 8.02, p<0.05), and excruciating (OR 20.17, p<0.001). Terrible (OR 33.3, p<0.05), aching (OR 44.5, p<0.05) and sore (OR 5.4, p<0.05) were selected more often by children with acute pain than with JIA.

Conclusion: Further studies will be required to determine the suitability of using the POM‐WDS with children.
Difficult intubation of a child through laryngeal mask airway with two tracheal tubes
Authors: KENDIIRLI TANIL , INCE ERDAL , KAVAZ ASLI , ÇIFTÇI ERGIN , ALANOĞLU ZEKERIYA , DOĞRU ÜLKER
Published: April 2006

Difficult tracheal intubation occurs infrequently. It is estimated that difficult laryngoscopy occurs in 1–2% of patients. Tracheal intubation of especially small infants can be challenging. When faced with a difficult airway, intubation through a laryngeal mask airway is one method of obtaining a secure airway. Here, we report a 23‐mo‐old girl with chronic lung disease and severe pneumonia, who was admitted to our paediatric intensive care unit. Since the patient could not be intubated by the standard method, because her larynx was up and forward, she was intubated successfully with a laryngeal mask airway through which two consecutive tracheal tubes were inserted.

Conclusion: Laryngeal mask airway has an important role as a back‐up device in case direct visualization of the larynx is not possible.
Biomimetics: its practice and theory
Authors: Vincent Julian F.V , Bogatyreva Olga A , Bogatyrev Nikolaj R , Bowyer Adrian , Pahl Anja-Karina
Published: April 2006

Biomimetics, a name coined by Otto Schmitt in the 1950s for the transfer of ideas and analogues from biology to technology, has produced some significant and successful devices and concepts in the past 50 years, but is still empirical. We show that TRIZ, the Russian system of problem solving, can be adapted to illuminate and manipulate this process of transfer. Analysis using TRIZ shows that there is only 12% similarity between biology and technology in the principles which solutions to problems illustrate, and while technology solves problems largely by manipulating usage of energy, biology uses information and structure, two factors largely ignored by technology.
Elastic and transport properties of cellular solids derived from three-dimensional tomographic images
Authors: Knackstedt Mark A , Arns Christoph H , Saadatfar Mohammad , Senden Tim J , Limaye Ajay , Sakellariou Arthur , Sheppard Adrian P , Sok Rob M , Schrof Wolfgang , Steininger H
Published: April 2006

We describe a three-dimensional imaging and analysis study of eight industrial cellular foam morphologies. The foam morphologies were generated by differing industrial processing methods. Tomograms are acquired on an X-ray micro-computed tomography facility at scales of approximately equal to

at resolutions down to 7 μm. The image quality is sufficient in all cases to measure local structure and connectivity of the foamed material, and the field of view large enough to calculate a range of material properties. Phase separation into solid and porous components is straightforward.

Three-dimensional structural characteristics are measured directly on the porous and solid phases of the images. A number of morphological parameters are obtained, including pore volume-to-surface-area ratio, connectivity, the pore and solid phase size distributions defined by maximal sphere openings and chord length measurements. We further calculate the pore size distribution associated with capillary pressure via simulating of mercury drainage on the digital images.

The binarized microstructures are used as a basis for calculations of transport properties (fluid permeability, diffusivity and thermal conductivity) and elastic moduli. From the data, we generate property–porosity relationships for the range of foam morphologies imaged and quantitatively analyse the effects of porosity and microstructure on the resultant properties of the foams.

We compare our numerical data to commonly used theoretical and empirical property–porosity relationships. For thermal conductivity, we find that the numerical results agree extremely well with an empirical expression based on experimental data of various foams. The upper Hashin–Shtrikman bound also provides an excellent prediction of the data across all densities. From simulation of the diffusivity, we can define the tortuosity of the pore space within the cellular solid. We find that different processing methods lead to strong variations in the tortuosity of the pore space of the foams. For elastic properties, our results show that for the Young modulus,
E
, both the differential effective medium theory and the classical correlation

give a good correlation. Assuming a constant Poisson's ratio

leads to reasonable agreement. The best correlation for

is given by assuming a slight variation in

as a linear function of porosity. The permeability of the foams varies over three orders of magnitude. Correlations for permeability based on the classical Kozeny–Carman equation lead to reasonable agreement, except at the lowest porosities. Permeability estimations based on mercury porosimetry give excellent agreement for all foams.
Cellular automaton approach to electromagnetic wave propagation in dispersive media
Authors: Janowicz M.W , Ashbourn J.M.A , Orłowski Arkadiusz , Mostowski Jan
Published: April 2006

Extensions of Białynicki-Birula's cellular automaton are proposed for studies of the one-dimensional propagation of electromagnetic fields in Drude metals, as well as in both transparent, dispersive and lossy dielectrics. These extensions are obtained by representing the dielectrics with appropriate matter fields, such as polarization together with associated velocity fields. To obtain the different schemes for the integration of the resulting systems of linear partial differential equations, split-operator ideas are employed. Possible further extensions to two-dimensional propagation and for the study of left-handed materials are discussed. The stability properties of the cellular automaton treated as a difference scheme are analysed.
Increase in BrAO1 gene expression and aldehyde oxidase activity during clubroot development in Chinese cabbage (Brassica rapa L.)
Authors: ANDO SUGIHIRO , TSUSHIMA SEIYA , TAGIRI AKEMI , KAMACHI SHINICHIRO , KONAGAYA KEN‐ICHI , HAGIO TAKASHI , TABEI YUTAKA
Published: April 2006

In clubroot disease, gall formation is induced by infection with the obligate biotroph Plasmodiophora brassicae due to increased levels of auxins and cytokinins. Because aldehyde oxidase (AO) may be involved in auxin biosynthesis in plants, we isolated two AO genes (BrAO1 and BrAO2) from Chinese cabbage (Brassica rapa ssp. pekinensis cv. Muso), which are the most similar to AAO1 among Arabidopsis AO genes, and examined their expressions during clubroot development. The expression of BrAO1 was enhanced in inoculated roots from 15 days post‐inoculation (dpi) when visible clubroots were still undetectable. Thereafter, BrAO1 expression increased with clubroot development compared with uninoculated roots, although BrAO2 expression was repressed. In situ hybridization revealed that BrAO1 was strongly expressed in tissues that were invaded by immature plasmodia at 35 dpi, suggesting that BrAO1 expression was enhanced by the pathogen in order to establish its pathogenesis. In addition, we detected AO activity, as evidenced by the occurrence of at least six bands (BrAO‐a to BrAO‐f) in the roots of Chinese cabbage using an active staining method with benzaldehyde and indlole‐3‐aldehyde as the substrate. Coincidental with BrAO1 expression, the signals of BrAO‐a and BrAO‐d increased with inoculation by P. brassicae during clubroot development compared with healthy roots, resulting in an increase in total AO activity. By contrast, the band BrAO‐b decreased post‐inoculation, in parallel with the expression of BrAO2. The other bands of activity were not clearly influenced by the infection. Based on these results, we discuss the involvement of AO in auxin‐overproduction during clubroot development in Chinese cabbage.
Introgression variability among Iberian brown trout Evolutionary Significant Units: the influence of local management and environmental features
Authors: ALMODÓVAR A. , NICOLA G. G. , ELVIRA B. , GARCÍA‐MARÍN J. L.
Published: April 2006

1. A comprehensive analysis was carried out on the effects of stocking on the genetic structure of Iberian brown trout evolutionary lineages. Introgression and genetic diversity were estimated from allozyme results of 307 populations based on own data (180) and available literature (127). Stocking records, angling regulations and environmental features related to hatchery trout performance were also analysed to determine the underlying mechanisms of the introgression effects.

2. Fifty per cent of analysed populations showed introgression by genes of hatchery origin. The mean introgression estimated by the single locus approach was 0.134. An increment of both heterozygosity and polymorphism was observed when introgression increased in stream‐dwelling populations, which could finally produce a homogenisation of the genetic structure of populations and a decrease of the species’ genetic diversity.

3. Introgression rate varied among Iberian evolutionary lineages (Evolutionary Significant Units), and was correlated with the stocking effort, except for the North Atlantic basins. The lack of adaptations for migratory behaviour in hatchery trout could explain the low impact of stocking in North Atlantic rivers where anadromous populations occur.

4. Angling regulation did not seem to influence the survival of hatchery trout. Introgression tends to be higher in heavily stocked localities with fertile waters and stable discharge, which may favour the performance of hatchery trout.

5. Trout management must be based on increasing population size by means of habitat improvement and sustainability of naturally reproducing wild stocks through appropriate angling regulations.
Non‐cardiac chest pain: an update
Authors: Fass R. , Dickman R.
Published: April 2006

Abstract  Non‐cardiac chest pain (NCCP) is very common, affecting up to a quarter of the USA adult population. Recent studies have shown that the disorder has a profound impact on patient's quality of life and is associated with marked increase in utilization of healthcare resources. Non‐cardiac chest pain is a heterogeneous disorder with gastrointestinal and non‐gastrointestinal causes. After excluding a cardiac cause, most NCCP patients are treated by cardiologists or primary care physicians and only the minority are referred to a gastroenterologist for further work‐up. Gastro‐oesophageal reflux disease (GORD) is the most common cause for NCCP. The role of oesophageal dysmotility in NCCP has been discounted in recent years. However, visceral hyperalgesia has been shown to play an important role in symptom generation of non‐GORD‐related NCCP. The main therapeutic interventions in GORD‐related NCCP patients are potent antireflux modalities and pain modulators in those with non‐GORD‐related NCCP.
A single nucleotide polymorphism in the β‐tubulin gene distinguishing two genotypes of Erysiphe necator expressing different symptoms on grapevine
Authors: Amrani L. , Corio‐Costet M.‐F.
Published: April 2006

The biotrophic fungus Erysiphe necator (formerly Uncinula necator), for which two genetic groups have been described in European vineyards, is the causal agent of grapevine powdery mildew. By analysing the pathogen population with respect to polymorphism in the sequence of the β‐tubulin gene, which distinguishes two groups of isolates, a new tool was developed for epidemiological and population studies and tested in the vineyard. As in many ascomycetes, the β‐tubulin gene of E. necator (Entub) includes six introns and seven exons and encodes a 447‐amino‐acid protein. A single nucleotide polymorphism (SNP) in the intron‐3 region of the Entub gene distinguished two genetic groups (A and B). This method was used to examine differences in the ratio of the two groups from a total of 289 grape powdery mildew samples collected at the beginning of the growing season from either flag shoots or leaves with sparse‐spot symptoms in four different vineyards. The SNP in the intron‐3 region of the β‐tubulin gene, similar to SNPs in the CYP51 gene, was associated with genotypes A and B of E. necator and confirmed the existence of two sympatric populations of the pathogen in the French vineyards. Differences in the relative proportions of each group varied with the presence or absence of flag‐shoot symptoms and with the region in which isolates had been collected.