bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidation of Benzyl Alcohols by the Laccase-Mediator System (LMS) a Comprehensive Kinetic Description
Authors: Potthast A. , Rosenau T. , Fischer K.
Published: March 2005

Investigations into the reaction kinetics of the laccase-mediator system (LMS) have been carried out. Two widely used mediators, 2,2′-azino-bis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS,3) and 1-hydroxybenzotriazole (HOBT,4), were compared by means of a model reaction, the oxidation of 2,4-dimethoxybenzyl alcohol (DMBA,1) to 2,4-dimethoxybenzaldehyde (DMA,2). The consumption of dioxygen was recorded electrochemically, substrate consumption and product formation were monitored by GLC.

With ABTS as the mediator, the LMS reaction proceeded in two clearly distinguishable stages. The first phase is characterized by a fast decrease in oxygen with zero-order kinetics and no detectable formation of 2,4-dimethoxybenzaldehyde (2). ABTS is converted into oxidized species, the cation radical6and the dication7, respectively. In the second phase, oxygen consumption was considerably slower and followed a second-order kinetics, while the benzaldehyde was produced according to a zero-order rate law. According to the kinetic studies, the ABTS dication, but not the enzyme itself, is acting as the actual oxidant. The rate of oxidation product formation increased with increasing mediator / benzyl alcohol ratio. Less oxygen than the equivalent amount was consumed in the second reaction stage indicating that the oxidized ABTS formed in the first stage acts as an oxidant reservoir, being reduced to ABTS in turn.

The LMS reaction with HOBT (4) as the mediator did not exhibit distinguishable phases, and was characterized by a comparatively slow oxygen uptake with zero-order kinetics throughout. Enzymatic oxidation of HOBT to the HOBT radical (5), which acts as the actual oxidant towards the benzyl alcohol, was the rate-determining step. The production of 2,4-dimethoxybenzaldehyde thus followed a zeroorder rate law as well. The reaction rate increased with increasing HOBT / benzyl alcohol ratios. Increasing concentrations of4caused less oxygen to be consumed per equivalent of benzaldehyde formed, indicating the occurrence of another reaction pathway at high mediator charges. At low HOBT / benzyl alcohol ratios the HOBT radical (5) acts as one-electron oxidant and is reduced to HOBT in a reversible process. In contrast, at higher HOBT / benzyl alcohol ratios5acts as a three-electron oxidant, being irreversibly reduced to benzotriazole. At commonly employed mediator concentrations, a superposition of both mechanisms results. The pure borderline cases can only be observed at HOBT / benzyl alcohol ratios below 1 and above 6, respectively.
Centrifuge Modeling of Rigid Square Footings on Weak Jointed Rock
Authors: Dunham L , Valsangkar AJ , Schriver AB
Published: March 2005

Four series of centrifuge tests were performed using a model rock made from a mixture of sand, bentonite, cement, and water. Tests were conducted to determine the effect of horizontal and vertical discontinuities in the bedrock on the load settlement response of a rigid, shallow footing. A prototype footing, measuring 1 m × 1 m, was simulated in the study. Horizontal and vertical joints, in-filled with compressible material, were simulated by incorporating thin seams of styrofoam. Results from this study are compared to the commonly used methods used to predict the ultimate bearing capacity of footings on jointed rock mass. It is concluded that the existing methods to predict the bearing capacity are conservative for the range of design parameters studied in this research.
Behavior of Irradiated Type 316 Stainless Steels under Low-Strain-Rate Tensile Conditions
Authors: Yoshitake T , Yamagata I , Akasaka N , Nakamura Y , Tsai H , Cole J , Allen T
Published: March 2005

The effects of lower strain rate on the tensile behavior of 12 % cold-worked type 316 stainless steels irradiated in the EBR-II reactor under low-dose-rate and moderate temperature conditions were investigated. Tensile tests were carried out at a strain rate of 1 × 10−7/s. Post-test fractography and microstructural characterization were also performed. Irradiation temperature and dose appeared to have the greatest effect on hardening and ductility loss, whereas dose rate appeared to have less apparent effects. In conjunction with earlier work performed on the same material at a strain rate of 1 × 10−3/s, there was no significant effect of strain rate on tensile behavior under the irradiation conditions examined. For fracture behavior, the material after irradiation exhibited typical ductile fracture during both high and low-strain-rate tests.
Fracture and Strength of Ceramic Notched Elements under Compression
Authors: Zheng X , Zhao K , Yan J , Wang H
Published: March 2005

Experimental results of the compression fracture strength of ceramic notched elements are summarized and analyzed in the present paper. The fracture model of ceramic notched elements under compression can be put forward based on Griffith's theory of brittle fracture. It is shown that the fracture of Al2O3 ceramics under compression loading is a typical brittle one induced by tensile stress, irrespective of whether the specimens are with or without a notch. The test results show that the product of the compression notch strength and the stress concentration factor is equal to the compression fracture strength, and the validity of the above-mentioned fracture model is thus checked. Finally, the procedures for predicting the fracture criteria with given survivability for Al2O3 ceramic notched elements can be developed based on the test results and the analysis mentioned above.
A Methodology for Fuel Tank Durability Test Development
Authors: Mayer J M , Long KW , Lee Y-L
Published: March 2005

A method is presented that describes the selection of a multiaxial or a uniaxial testing procedure to validate fuel tank strap durability. Strain gage rosette data recorded from a proving ground schedule were used to determine the loading experienced on the fuel tank strap. Representative testing was conducted using both multiaxial and uniaxial testing procedures. This method utilizes advanced durability software and fatigue analysis to evaluate both multiaxial and uniaxial laboratory test results. The method establishes a set of criteria for the selection of multiaxial or uniaxial durability test procedures.
Sequential Development of Electrical and Chemical Synaptic Connections Generates a Specific Behavioral Circuit in the Leech
Authors: Marin-Burgin Antonia , Eisenhart F. James , Baca Serapio M. , Kristan William B. , French Kathleen A.
Published: March 2005

Neuronal circuits form during embryonic life, even before synapses are completely mature. Developmental changes can be quantitative (e.g., connections become stronger and more reliable) or qualitative (e.g., synapses form, are lost, or switch from electrical to chemical or from excitatory to inhibitory). To explore how these synaptic events contribute to behavioral circuits, we have studied the formation of a circuit that produces local bending (LB) behavior in leech embryos. This circuit is composed of three layers of neurons: mechanosensory neurons, interneurons, and motor neurons. The only inhibition in this circuit is in the motor neuron layer; it allows the animal to contract on one side while relaxing the opposite side. LB develops in two stages: initially touching the body wall causes circumferential indentation (CI), an embryonic behavior in which contraction takes place around the whole perimeter of the segment touched; one or 2 d later, the same touch elicits adult-like LB. Application of bicuculline methiodide in embryos capable of LB switched the behavior back into CI, indicating that the development of GABAergic connections turns CI into LB. Using voltage-sensitive dyes and electrophysiological recordings, we found that electrical synapses were present early and produced CI. Inhibition appeared later, shaping the circuit that was already connected by electrical synapses and producing the adult behavior, LB.
Rückführung dynamischer Kraft- und Drehmomentmessungen mithilfe von Laser-Doppler-Interferometrie (Traceabilty of Dynamic Force and Torque Calibrations by Means of Laser-Doppler-Interferometry)
Authors: Bruns Thomas , Kobusch Michael
Published: March 2005

Der vorliegende Artikel stellt die neusten Entwicklungen der Physikalisch-Technischen Bundesanstalt (PTB) im Bereich dynamischer Kalibriermethoden für Kraft- und Drehmomentaufnehmer vor. Zusätzlich zu den bereits seit einiger Zeit vorhandenen Einrichtungen zur Kalibrierung mit sinusförmigen Kräften sind zwei neue Geräte im Laufe der letzten drei Jahre entwickelt und aufgebaut worden: eines zur rückführbaren Erzeugung stoßförmiger Kräfte, das andere zur dynamischen Kalibrierung mit (zunächst sinusförmigen) Drehmomenten.
Elektrophile Aktivierung und Cycloisomerisierung von Eninen: ein Weg zu funktionalen Cyclopropanen
Authors: Bruneau Christian
Published: March 2005

Umsetzungen von Eninen in Gegenwart von Übergangsmetallkatalysatoren spielen bei selektiven Synthesen cyclischer Verbindungen seit jeher eine wichtige Rolle. Ein bedeutender Fortschritt waren jüngste Entwicklungen bei der Aktivierung von Kohlenstoff‐Kohlenstoff‐Dreifachbindungen durch elektrophile Metallzentren, die neue Ansätze für die selektive Synthese von Cyclopropanderivaten aus Eninen hervorbrachten. Am Mechanismus dieser Reaktionen sind katalytische Spezies mit sowohl ionischem als auch Cyclopropylcarbenoid‐Charakter beteiligt. Diese Art der Aktivierung könnte auch bei anderen ungesättigten Kohlenwasserstoffen sowie für katalytische Reaktionssequenzen angewendet werden. Dieser Kurzaufsatz diskutiert die neuesten Entwicklungen bei der elektrophilen Aktivierung von Eninen und zeigt, dass einfache Katalysatoren wie [Ru3(CO)12], PtCl2 und kationische Goldkomplexe wirksame Vorstufen für die katalytische Synthese von funktionalen polycyclischen Verbindungen sind.
Transport of small molecules through mechanically elongated polymeric membranes
Authors: Puri P. , Hinestroza J. , De Kee D.
Published: March 2005

This contribution presents an analysis of the problem of diffusion through membranes, incorporating a realistic downstream boundary condition. The analysis can be applied to operations involving geomembranes. Graphs are presented to show the effect of the various dimensionless parameters. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1200–1203, 2005
Synthesis and characterization of novel phenyl‐substituted poly(p‐phenylene vinylene) derivatives
Authors: Tang Rupei , Xu Xinjun , Cheng Caixia , Yu Gui , Liu Yunqi , Xi Fu
Published: March 2005

Two novel phenyl‐substituted poly(p‐phenylene vinylene) derivatives, poly{2‐[3′,4′‐(2″‐ethylhexyloxy)(3″,7″‐dimethyloctyloxy)benzene]‐1,4‐phenylenevinylene} (EDP‐PPV) and poly{2‐[3′,4′‐(2″‐ethylhexyloxy)(3″,7″‐dimethyloctyloxy)benzene]‐5‐methoxy‐1,4‐phenylenevinylene} (EDMP‐PPV), and their copolymer, poly{2‐[3′,4′‐(2″‐ethylhexyloxy)(3″,7″‐dimethyloctyloxy)benzene]‐1,4‐phenylene‐vinylene‐co‐2‐[3′,4′‐(2″‐ethylhexyloxy)(3″,7″‐dimethyloctyloxy)benzene]‐5‐methoxy‐1,4‐phenylenevinylene} (EDP‐co‐EDMP‐PPV; 4:1, 1:1, and 1:4), were successfully synthesized according to the Gilch route. The structures and properties of the monomers and the resulting conjugated polymers were characterized with 1H‐NMR, 13C‐NMR, elemental analysis, gel permeation chromatography, thermogravimetric analysis, ultraviolet–visible absorption spectroscopy, and photoluminescence and electroluminescence (EL) spectroscopy. The EL polymers possessed excellent solubility in common solvents and good thermal stability with a 5% weight loss temperature of more than 380°C. The weight‐average molecular weights and polydispersity indices of EDP‐PPV, EDMP‐PPV, and EDP‐co‐EDMP‐PPV were 1.40–2.58 × 105, and 1.19–1.52, respectively. Double‐layer light‐emitting diodes with the configuration of indium tin oxide/polymer/tris(8‐hydroxyquinoline)aluminum/Al devices were fabricated, and EDP‐co‐EDMP‐PPV (1:1) showed the highest EL performance and exhibited a maximum luminance of 1050 cd/m2 at 19.5 V. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1259–1266, 2005
An EPR and ENDOR Investigation of a Series of Diazabutadiene–Group 13 Complexes
Authors: Baker Robert J. , Farley Robert D. , Jones Cameron , Mills David P. , Kloth Marc , Murphy Damien M.
Published: March 2005

Paramagnetic diazabutadienegallium(II or III) complexes, [(Ar‐DAB)2Ga] and [{(Ar‐DAB.)GaX}2] (X=Br or I; Ar‐DAB={N(Ar)C(H)}2, Ar=2,6‐diisopropylphenyl), have been prepared by reactions of an anionic gallium N‐heterocyclic carbene analogue, [K(tmeda)][:Ga(Ar‐DAB)], with either “GaI” or [MoBr2(CO)2(PPh3)2]. A related InIII complex, [(Ar‐DAB.)InCl2(thf)], has also been prepared. These compounds were characterised by X‐ray crystallography and EPR/ENDOR spectroscopy. The EPR spectra of all metal(III) complexes incorporating the Ar‐DAB ligand, [(Ar‐DAB.)MX2(thf)n] (M=Al, Ga or In; X=Cl or I; n=0 or 1) and [(Ar‐DAB)2Ga], confirmed that the unpaired spin density is primarily ligand centred, with weak hyperfine couplings to Al (a=2.85 G), Ga (a=17—25 G) or In (a=26.1 G) nuclei. Changing the N substituents of the diazabutadiene ligand to tert‐butyl groups in the gallium complex, [(tBu‐DAB.)GaI2] (tBu‐DAB={N(tBu)C(H)}2), changes the unpaired electron spin distribution producing 1H and 14N couplings of 1.4 G and 8.62 G, while the aryl‐substituted complex, [(Ar‐DAB.)GaI2], produces couplings of about 5.0 G. These variations were also manifested in the gallium couplings, namely aGa ∼1.4 G for [(tBu‐DAB.)GaI2] and aGa ∼25 G for [(Ar‐DAB.)GaI2]. The EPR spectra of the gallium(II) and indium(II) diradical complexes, [{(Ar‐DAB.)GaBr}2], [{(Ar‐DAB.)GaI}2], [{(tBu‐DAB.)GaI}2] and [{(Ar‐DAB.)InCl}2], revealed doublet ground states, indicating that the GaGa and InIn bonds prevent dipole–dipole coupling of the two unpaired electrons. The EPR spectrum of the previously reported complex, [(Ar‐BIAN.)GaI2] (Ar‐BIAN=bis(2,6‐diisopropylphenylimino)acenaphthene) is also described. The hyperfine tensors for the imine protons, and the aryl and tert‐butyl protons were obtained by ENDOR spectroscopy. In [(Ar‐DAB.)GaI2], gallium hyperfine and quadrupolar couplings were detected for the first time.
Intronic sequence variants of the CDKN2A gene in melanoma pedigrees
Authors: Harland Mark , Taylor Claire F. , Bass Sylvia , Churchman Michael , Randerson‐Moor Juliette A. , Holland Elizabeth A. , Mann Graham J. , Bishop D. Timothy , Newton Bishop Julia A.
Published: March 2005

Germ‐line mutations of the tumor‐suppressor gene CDKN2A predispose individuals to melanoma in families worldwide. However, coding mutations of CDKN2A have not been detected in a significant proportion of those affected. The identification of a disease‐associated intronic mutation of CDKN2A in UK families, which has proved to be the most common CDKN2A mutation as yet identified in this population, has highlighted the possibility that additional causal mutations may lie within the intronic sequence of the gene. In this article, we describe the comprehensive screening of 109 English and 26 Australian melanoma pedigrees for intronic mutations of CDKN2A. In total, 24 sequence variants were identified across the two introns of the gene. We show evidence that two of the CDKN2A intronic variants (IVS1+1104 C > A and IVS1−1104 C > G) predispose to melanoma. IVS1+1104 was shown to result in the aberrant splicing of both p16INK4a and p14ARF mRNA. Overall, however, the proportion of English melanoma families with these variants is small. © 2005 Wiley‐Liss, Inc.
Conformation and dynamics of a self‐avoiding sheet: Bond‐fluctuation computer simulation
Authors: Pandey Ras B. , Anderson Kelly L. , Heinz Hendrik , Farmer B.L.
Published: March 2005

The conformation and dynamics of a self‐avoiding sheet are analyzed by the bond‐fluctuating Monte Carlo method. The mean‐square displacement of the center of mass of the sheet and that of its center node (R) show asymptotic diffusive behavior. The segmental dynamics in short and long time regimes can be deduced from the motion of the center node described by the power law$R_n^2 \simeq C_1 t^{2\mu } + C_2 t^{2\nu }$with μ ≃ 0.13 and ν ≃ ½, whereC1andC2are fitting constants andtis the time. The radius of gyration,Rg, scales with the linear size,Ls, of the sheet asRg≃Nγwith γ ≃ ½ andN=L, and this is consistent with the conformational analysis of open tethered membranes with excluded‐volume constraints. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1041–1046, 2005
Specific heat of RNi4Al (R = Y, Ce, Nd) compounds
Authors: Toliński T. , Szewczyk A. , Gutowska M. , Kowalczyk A.
Published: March 2005

The temperature dependence of the specific heat for the YNi4Al, CeNi4Al and NdNi4Al compounds has been studied. The first one is nonmagnetic and serves as a reference material. The Ce‐based compound is paramagnetic and shows an anomaly related to a Kondo and/or antiferromagnetic interaction, whereas the Nd‐based compound reveals a peak at 6 K connected with a transition to the ferromagnetic order. The specific heat has been analyzed considering the electronic contribution, the Schottky anomaly, and the lattice contribution in frames of the Debye model.

Anomaly in specific heat and minimum in resistivity [8].

image

Anomaly in specific heat and minimum in resistivity [8].

(© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pairwise non‐parametric non‐inferiority tests in 3 × 3 cross‐over trials: should we adjust for period?
Authors: Duchateau Luc , Janssen Paul
Published: March 2005

Before an active compound can be registered as a drug, it needs to be demonstrated that it does not cause particular unwanted compound specific side effects. Demonstrating non‐inferiority of an active drug with placebo with respect to an unwanted side effect is often based on pharmacodynamic 3 × 3 cross‐over trials, with the third treatment arm consisting of a positive control. The main comparison then is the pairwise comparison between active drug and placebo. In this paper, two different non‐parametric methods with adjustment for period effect are compared with the non‐parametric non‐adjusted test and the parametric period‐adjusted test with respect to size and power. The non‐parametric test with period adjustment based on rank alignment has generally the largest power, but its size exceeds the nominal significance level. The non‐parametric test with period adjustment based on stratification has low power for trials with a small number of subjects. The non‐parametric test without period adjustment is a valid alternative in such cases, but its power decreases substantially in the presence of period effects. In the case of unbalanced designs, however, only the non‐parametric test with period adjustment based on stratification can be used. Copyright © 2005 John Wiley & Sons, Ltd.
Scale and seasonal sex‐ratio trends in northern goshawk Accipiter gentilis broods
Authors: Byholm Patrik , Brommer Jon E. , Saurola Pertti
Published: March 2005

In many populations of size dimorphic birds, brood sex ratios change with advancing laying date. The slopes of these trends, however, vary in time and space, both between and within species. We studied brood sex ratios (proportion of males) of northern goshawks Accipiter gentilis in Finland in relation to laying date using ringing data from 1989 to 1998. At the nationwide scale, i.e. the whole of Finland, between‐year variation in offspring sex ratio was moderate, and the sex ratio did not change with later laying date. At a regional scale, the sex ratio was seasonally constant in one region but decreased in another, although the laying‐date/brood‐size relationship was identical. Hence, the size and sex composition of goshawk broods are locally two uncoupled facets of reproduction. Both the national and regional patterns differ drastically from the pattern of a Dutch population, where sex ratio increased seasonally. We suggest that spatial variation in inter‐annual seasonal sex‐ratio trends might be indicative of the scale at which sex‐ratio feedback functions. The sex ratio of breeders is a factor that could add to the understanding of the observed geographical differences in seasonal sex‐ratio patterns.
Wooded habitat edges as refugia from microtine herbivory in tallgrass prairies
Authors: Nickel Anne M. , Danielson Brent J. , Moloney Kirk A.
Published: March 2005

Meadow voles, Microtus pennsylvanicus, affect the species composition, distribution, and succession of plants in grassland ecosystems, but the effects of voles on herbaceous plants when grasslands are bordered by wooded edges is not known. We investigated the impact of wooded edges on vole distribution and herbivory of relatively palatable and unpalatable native prairie plant species by studying five reconstructed tallgrass prairies with wooded edges in central Iowa. A 50×50 m trapping grid at each site was established to determine the proportion of voles captured at various distances from the edge. We found that meadow voles were less abundant at wooded edges and, in general, increased in number toward the prairie interior. Seedlings of purple prairie clover (Dalea purpurea) and Illinois bundleflower (Desmanthus illinoensis), a relatively palatable and unpalatable species, respectively, were transplanted onto simulated gopher mounds 2, 5, 10, 20 and 30 m from the edge. The number of plants grazed per species per mound was determined 1 week and 4 weeks after planting. The amount of herbivory on both species was significantly different by distance, with fewer plants eaten 2 m from the edge. Interestingly, the amount of herbivory on relatively unpalatable plants did not differ from more palatable plants. Herbivory on both plant species also varied by site, such that sites with lower vole density tended to have lower amounts of herbivory. These results indicate that wooded edges do have an effect on meadow vole distribution and native prairie seedling herbivory. Because voles avoid wooded edges, seedlings of any species may experience a small refuge from herbivory along wooded edges.
Women and the Spanish-American Wars of Independence: An Overview
Authors: Brewster Claire
Published: March 2005

This article looks at the ways in which Spanish American women exploited the political and social turmoil of the late 18th and early 19th centuries to move beyond their traditional sphere of influence in the home. Women directly participated in the Túpac Amaru Rebellion (1780–1781) and in the Wars of Independence (1810–1825) providing funding, food supplies, infrastructure and reinforcements for the troops, and nursing the wounded. Others contributed by taking part in the physical fighting (both openly and disguised as men) and a few led troops into battle. This article looks at some of the individuals behind the statistics and reveals their determination to participate despite the punishments imposed on women found guilty of disloyalty to the Spanish crown. Spanish colonial law had to be amended to ensure that women dissidents were given as equally harsh sentences as men. In the immediate post-independence period, rather than be seen as misfits or a threat to the patriarchal system, several of these women were given national awards.
Embodying Memory: Women and the Legacy of the Military Government in Chile
Authors: Moenne María Elena Acuña
Published: March 2005

The article argues that the prohibition of abortion in Chile, other than when the mother's life is in danger, is a form of human rights violation targeting women specifically. The Pro-Birth Policy was established in Pinochet's Chile as a response to the previous government's attempts, under Allende, to encourage family planning and to educate and inform women about their choices. This had been done to put an end to the increase in back-street abortions with the inevitable toll on women's lives. Pinochet's regime reversed these women-oriented family planning policies, and criminalized abortion, on the basis of costs to the state and, more importantly, the need to increase the birth rate for reasons of national security. Women's bodies were used by the Pinochet regime, both by sexual violence and torture, and by the denial of women's reproductive and sexual rights, as a means to impose discipline and order on society. The fact that this is still not acknowledged in the construction of a collective memory indicates that the issue has not yet been resolved in democratic Chile.
Ultra-high vacuum scanning tunneling microscopy and theoretical studies of 1-halohexane monolayers on graphite
Authors: Müller Thomas , Werblowsky Tova L. , Florio Gina M. , Berne Bruce J. , Flynn George W.
Published: March 2005

A simple model system for the 2D self-assembly of functionalized organic molecules on surfaces was examined in a concerted experimental and theoretical effort. Monolayers of 1-halohexanes were formed through vapor deposition onto graphite surfaces in ultrahigh vacuum. Low-temperature scanning tunneling microscopy allowed the molecular conformation, orientation, and monolayer crystallographic parameters to be determined. Essentially identical noncommensurate monolayer structures were found for all 1-halohexanes, with differences in image contrast ascribed mainly to electronic factors. Energy minimizations and molecular dynamics simulations reproduced structural parameters of 1-bromohexane monolayers quantitatively. An analysis of interactions driving the self-assembly process revealed the crucial role played by small but anisotropic electrostatic forces associated with the halogen substituent. While alkyl chain dispersion interactions drive the formation of a close-packed adsorbate monolayer, electrostatic headgroup forces are found to compete successfully in the control of both the angle between lamella and backbone axes and the angle between surface and backbone planes. This competition is consistent with energetic tradeoffs apparent in adsorption energies measured in earlier temperature-programmed desorption studies. In accordance with the higher degree of disorder observed in scanning tunneling microscopy images of 1-fluorohexane, theoretical simulations show that electrostatic forces associated with the fluorine substituent are sufficiently strong to upset the delicate balance of interactions required for the formation of an ordered monolayer. The detailed dissection of the driving forces for self-assembly of these simple model systems is expected to aid in the understanding of the more complex self-assembly processes taking place in the presence of solvent.
Mediating Factors for the Long‐term Effects of Parental Alcoholism in Women: The Contribution of Other Childhood Stresses and Resources
Authors: Griffin Margaret L. , Amodeo Maryann , Fassler Irene , Ellis Michael A. , Clay Cassandra
Published: March 2005

The primary aim of this study was to identify the stresses and resources in childhood that mediate the relationship between parental alcoholism and adult outcomes in women. Adult outcomes included alcohol problems and measures of psychosocial adjustment. Standardized measures and a face‐to‐face interview were used to collect data on 290 community‐dwelling women, with siblings as collateral informants. Mediation analysis showed that the effect of parental alcoholism on several adult outcomes was indirect, mediated by the other stresses and resources examined. Contextual models such as those presented here are helpful in understanding the long‐term effects of childhood environment on women.
Does ultraviolet reflectance accentuate a sexually selected signal in terns?
Authors: Bridge Eli S. , Eaton Muir D.
Published: March 2005

Unlike the majority birds that replace their primaries once each year, most Sterna terns practice an unusual repeated wing molt, wherein a variable number of inner primaries are replaced twice or even three times in a single year. This seemingly redundant replacement of the primaries may serve as a sexually selected indicator of quality in that terns may evaluate potential mates based on the number of primaries they were able to replace twice or three times prior to the breeding season. To evaluate the potential of repeated molt as a social signal, we compared light‐reflectance curves and photon catches for new (twice‐molted) and old (once‐molted) primaries in three species of terns. We observed that old feathers reflected considerably less light across all wavelengths and found that in two of the three species examined the ultraviolet reflectance was disproportionably reduced in old feathers relative to the reduction in visible reflectance. Thus, the UV component of coloration in tern wing feathers may accentuate the difference between the new feathers generated by repeated wing molt and older, more worn feathers, thereby reinforcing a sexually selected signal of quality.
Review article: 13C‐urea breath test in the diagnosis of Helicobacter pylori infection – a critical review
Authors: Gisbert J. P. , Pajares J. M.
Published: March 2005

The urea breath test is a non‐invasive, simple and safe test which provides excellent accuracy both for the initial diagnosis of Helicobacter pylori infection and for the confirmation of its eradication after treatment.

Some studies have found no differences between urea breath test performed under non‐fasting conditions. The simplicity, good tolerance and economy of the citric acid test meal probably make its systematic use advisable. The urea breath test protocol may be performed with relatively low doses (<100 mg) of urea: 75 mg or even 50 mg seem to be sufficient. With the most widely used protocol (with citric acid and 75 mg of urea), excellent accuracy is obtained when breath samples are collected as early as 10–15 min after urea ingestion.

A unique and generally proposed cut‐off level is not possible because it has to be adapted to different factors, such as the test meal, the dose and type of urea, or the pre‐/post‐treatment setting. Fortunately, because positive and negative urea breath test results tend to cluster outside of the range between 2 and 5‰, a change in cut‐off value within this range would be expected to have little effect on clinical accuracy of the test.
Factors relating to soil fertility and species diversity in both semi‐natural and created meadows in the West Midlands of England
Authors: McCrea A. R. , Trueman I. C. , Fullen M. A.
Published: March 2005

The post‐war decline in the area and diversity of neutral meadows in Britain, resulting from agricultural intensification, has prompted schemes to restore and create new habitats. Their success relies on understanding the relations between soil fertility and species diversity. We have investigated these relations, using multivariate analysis, in 28 semi‐natural meadows and eight artificially created urban meadows. Mineralizable nitrogen was the most important soil characteristic in the semi‐natural sites; the more N the soil contained the fewer were the species characteristic of traditional meadows. Both potassium and total magnesium favoured diversity, perhaps because their deficiency in many traditionally managed meadows jeopardizes the survival of broad‐leaved species in competition with grasses. Available lead, at sub‐lethal concentrations and measured as a Pb:Ca ratio, appeared to favour diversity in the semi‐natural sites, possibly by inhibiting the uptake of P by competitive grasses and allowing the less competitive species associated with diversity to flourish. The main differences between the soils of the artificial and the semi‐natural meadows were that the former contained more extractable P and less mineralizable N and organic matter. It seems that large soil phosphorus concentrations may be the main reason why relatively few species colonize or survive in grassland on many urban soils.
Attraction of garden chafer, Phyllopertha horticola, to floral Japanese beetle lure
Authors: Ruther J. , Tolasch T.
Published: March 2005

Field experiments using funnel traps were performed on a golf course to investigate the attractiveness of a floral Japanese beetle lure for adults of the garden chafer, Phyllopertha horticola, a common European turf pest. Traps baited with 10 mg of the floral lure consisting of phenylethyl propionate + eugenol + geraniol (3 : 7 : 3) captured more adult garden chafers of both sexes than non‐baited control traps. In contrast, 1,3‐dimethyl‐2,4‐(1H, 3H)‐quinazolinedione, the sex pheromone of the closely related pale‐brown chafer P. diversa, neither influenced alone nor in combination with the floral lure the behaviour of adult garden chafers. The results suggest that the floral Japanese beetle lure might be used for monitoring or control of P. horticola.
Reproductive biology and pollinator limitation in a deceptive orchid, Serapias vomeracea (Orchidaceae)
Authors: PELLEGRINO GIUSEPPE , GARGANO DOMENICO , NOCE MARIA ELENA , MUSACCHIO ALDO
Published: March 2005

Deceptive orchid species that offer no floral rewards to pollinators often experience pollinator limitation. Serapias vomeracea is considered a particular example of terrestrial orchids using deceptive strategies because its sepals, petals and the lateral lobes of the hypochile form a small tube imitating a little hole that the insects use to rest. The pollination biology and breeding system were investigated in two populations of S. vomeracea in order to examine the extent of pollinator limitation. Visiting insects were immobile in the Serapias flowers during the early morning and late evening. The main pollinators were Oedemeridae and Lymexylidae (Coleoptera), but Hymenoptera (Ceratina, Eucera, Osmia) were also observed. Fruit set did not vary in response to floral display size, suggesting that variations in flower number per inflorescence and plant height were not responsible for attracting pollinators and thus reproductive success. Although S. vomeracea is self‐compatible, bagged inflorescences produced no fruits. Artificial pollination resulted in 95–100% fruit set by induced autogamy, 95–100% by geitonogamous pollination and 90–95% by xenogamous pollination. Fruit set in the open‐pollinated control was 13–18%. Fruit production was not related to the size, number or position of flowers. Pollinator observation and supplemented hand‐pollination indicated a positive relationship between fruit set and pollinator visitations in this species.
Angiogenesis: now and then
Authors: COSTA CARLA , SOARES RAQUEL , SCHMITT FERNANDO
Published: March 2005

Angiogenesis or new blood vessel formation plays an essential role during embryogenesis, adult vascular remodeling and in several pathological disorders, as in tumor development. Although sprouting of blood vessels is the principal angiogenic mechanism, additional ones, such as the recruitment of bone marrow‐derived cells, have recently been described. These processes are controlled by several molecules, although members of the VEGF family of angiogenic factors and its receptors seem to be the main mediators. Initially, VEGF receptors were described as endothelial specific; however, further studies have reported their presence in several types of cells of non‐endothelial origin, such as tumor cells. This VEGF receptor altered expression has suggested an angiogenesis‐independent growth advantage mechanism on certain types of cancers by the generation of autocrine loops. A possible role in tumorigenesis and a potential novel target in cancer therapy have been hypothesized. Detection of other receptors and molecules considered to be angiogenic players has also been observed on tumor cells. Currently, their clinical significance as well as their potential as therapeutic targets for the treatment of certain cancers is being evaluated, having in mind the future development of promising mechanism‐based therapies. The aspects mentioned above are the main focus of this review, which aims to throw light on recent findings respecting angiogenesis and novel therapeutic approaches.
Eocene shoshonitic mafic dykes intruding the Monashee Complex, British Columbia: a petrogenetic relationship with the Kamloops Group volcanic sequence?
Authors: Adams Matthew G , Lentz David R , Shaw Cliff SJ , Williams Paul F , Archibald Douglas A , Cousens Brian
Published: March 2005

The newly named Three Valley Suite (TVS) kersantite lamprophyre to shoshonitic mafic dykes of the Monashee Complex are inferred to be hypabyssal feeder dykes to an alkaline to calc-alkaline volcanic suite related to the Kamloops Group. These dykes were emplaced in a subvertical north-trending orientation coincident with inferred Eocene crustal extension (~50.0 Ma), based on the flat 40Ar/39Ar step-heating plateau of contact-metamorphic muscovite on the margin of a TVS dyke. These weakly altered mafic dykes are fine grained with phenocrysts (0.52.0 mm) of phlogopite, augite, amphibole, and olivine (pseudomorphed by clays), rare labradorite, and both primary and secondary carbonates set in a fine-grained groundmass of similar mineralogy consistent with their classification as plagioclase-bearing potassic diorite to kersantite lamprophyre. The dykes are weakly silica-undersaturated and alkalic (2.8 wt.% K2O, 7.7 wt.% MgO), with high large ion lithophile element contents (~300 times primitive mantle) and elevated high-field-strength element contents, with a prominent negative Nb (Ta) anomaly, and have radiogenic Nd and Sr isotopic signatures; these geochemical attributes are consistent with a calc-alkaline shoshonitic affinity. Therefore, it is inferred that the subducting oceanic plate influenced subcrustal mantle wedge metasomatism in the region. Decompression partial melting of this metasomatised lithospheric mantle was initiated by coupled rapid unroofing, regional trans pression, slab rollback, and slab window development to the south. The TVS is similar to the mafic volcanic rocks within the nearby Eocene volcanic rocks, suggesting that these dykes represent the feeder system to a volcanic field that is now eroded, i.e., a broad-terrane association.
Simple analytic equations of state for Sutherland fluids and square-well fluids
Authors: Jiuxun Sun
Published: March 2005

A simple analytic expression satisfying the limitation condition at low density for the radial distribution function of hard spheres is developed in terms of a polynomial expansion of nonlinear base functions and the CarnahanStarling equation of state. The simplicity and precision for the expression is superior to the well-known PercusYevick expression. The coefficients contained in the expression were determined by fitting the Monte-Carlo data for the first coordination shell, and by fitting both the Monte-Carlo data and the numerical results of the PercusYevick expression for the second coordination shell. The expression has been applied to develop analytic equations of state for Sutherland fluids and square-well fluids. The numerical results are in good agreement with computer-simulation data. PACS Nos.: 61.20.Gy, 64.10.+h, 05.70.Ce
Accurate Kohn-Sham potential for the 1s2s 3S state of the helium atom: Tests of the locality and the ionization-potential theorems
Authors: Salomonson Sten , Moller Fredrik , Lindgren Ingvar
Published: March 2005

The local KohnSham potential is constructed for the 1s2s 3S state of the helium atom, using the procedure proposed by van Leeuwen and Baerends (Phys. Rev. A, 49, 2138 (1994)) and the many-body electron density, obtained from the pair-correlation program of Salomonson and Öster (Phys. Rev. A, 40, 5559 (1989)). The KohnSham orbitals reproduce the many-body density very accurately, demonstrating the validity of the KohnSham model and the locality theorem in this case. The ionization-potential theorem, stating that the KohnSham energy eigenvalue of the outermost electron orbital agrees with the negative of the corresponding many-body ionization energy (including electronic relaxation), is verified in this case to nine digits. A KohnSham potential is also constructed to reproduce the HartreeFock density of the same state, and the KohnSham 2s eigenvalue is then found to agree with the same accuracy with the corresponding HartreeFock eigenvalue. This is consistent with the fact that in this model the energy eigenvalue equals the negative of the ionization energy without relaxation due to Koopmans' theorem. Related calculations have been performed previously, particularly for atomic and molecular ground states, but none of matching accuracy. In the computations presented here there is no conflict between the locality of the KohnSham potential and the exclusion principle, as claimed by Nesbet (Phys. Rev. A, 58, R12 (1998)). PACS Nos.: 31.15.Ew, 31.15.Pf, 02.30.Sa
Gene fusions and gene duplications: relevance to genomic annotation and functional analysis
Authors: Serres Margrethe H , Riley Monica
Published: March 2005

Background

Escherichia coli a model organism provides information for annotation of other genomes. Our analysis of its genome has shown that proteins encoded by fused genes need special attention. Such composite (multimodular) proteins consist of two or more components (modules) encoding distinct functions. Multimodular proteins have been found to complicate both annotation and generation of sequence similar groups. Previous work overstated the number of multimodular proteins in E. coli. This work corrects the identification of modules by including sequence information from proteins in 50 sequenced microbial genomes.

Results

Multimodular E. coli K-12 proteins were identified from sequence similarities between their component modules and non-fused proteins in 50 genomes and from the literature. We found 109 multimodular proteins in E. coli containing either two or three modules. Most modules had standalone sequence relatives in other genomes. The separated modules together with all the single (un-fused) proteins constitute the sum of all unimodular proteins of E. coli. Pairwise sequence relationships among all E. coli unimodular proteins generated 490 sequence similar, paralogous groups. Groups ranged in size from 92 to 2 members and had varying degrees of relatedness among their members. Some E. coli enzyme groups were compared to homologs in other bacterial genomes.

Conclusion

The deleterious effects of multimodular proteins on annotation and on the formation of groups of paralogs are emphasized. To improve annotation results, all multimodular proteins in an organism should be detected and when known each function should be connected with its location in the sequence of the protein. When transferring functions by sequence similarity, alignment locations must be noted, particularly when alignments cover only part of the sequences, in order to enable transfer of the correct function. Separating multimodular proteins into module units makes it possible to generate protein groups related by both sequence and function, avoiding mixing of unrelated sequences. Organisms differ in sizes of groups of sequence-related proteins. A sample comparison of orthologs to selected E. coli paralogous groups correlates with known physiological and taxonomic relationships between the organisms.
A Novel Triaxial Apparatus for Thermo-Mechanical Testing of Soils
Authors: Cekerevac C , Laloui L , Vulliet L
Published: March 2005

This paper describes a new triaxial apparatus for testing the thermo-mechanical behavior of soils. This triaxial apparatus accommodates samples 55 mm in diameter and 110mm in height. The cell is designed to perform compression tests under pressures up to 2 MPa and with temperatures ranging from 5°C to 90°C. The calibration of the device, as well as its precision and accuracy, is widely discussed in the paper. The related experimental procedures are also discussed. Finally, the results of tests performed on Kaolin are presented in order to highlight the features of the apparatus and to show some induced thermal effects on soils.
Measuring Soil Contact Pressure on a Solid Boundary and Quantifying Soil Arching
Authors: Talesnick M
Published: March 2005

The paper presents the design, development, and calibration of a soil contact pressure transducer, based on the null method. Air pressure regulated in a tightly controlled PID loop balances the output of a strain gage bridge bonded to the sensing element. This action maintains the sensing element in an underflected state. The result is that the membrane does not interact with the surrounding soil, and errors due to arching are eliminated. In theory, the air pressure required to keep the sensing element in its undeflected state should be equal to the soil contact pressure applied at the soil boundary interface.

Calibration of the sensor reveals that its response is exactly as anticipated. The ratio between the required null pressure and applied soil pressure at the boundary interface is 1:1 and independent of soil type, soil stiffness, and load history. The paper presents calibration of the sensor for two very different sands, each at two significantly different levels of relative density.

The sensitivity of the sensor is a function of the control software. In its present version the sensor responds accurately to pressure imbalances of 0.3 kPa.
Statistics of Decision Making in the Leech
Authors: Garcia-Perez Elizabeth , Mazzoni Alberto , Zoccolan Davide , Robinson Hugh P. C. , Torre Vincent
Published: March 2005

Animals continuously decide among different behaviors, but, even in invertebrates, the mechanisms underlying choice and decision are unknown. In this article, leech spontaneous behavior was tracked and quantified for up to 12 h. We obtained a statistical characterization, in space and time domains, of the decision processes underlying selection of behavior in the leech. We found that the spatial distribution of leech position in a uniform environment is isotropic (the same in all directions), but this isotropy is broken in the presence of localized external stimuli. In the time domain, transitions among behaviors can be described by a Markov process, the structure of which (allowed states and transitions) is highly conserved across individuals. Finally, a wide range of recurrent, deterministic motifs was identified in the apparently irregular and unstructured exploratory behavior. These results provide a rigorous description of the inner dynamics that control the spontaneous and continuous flow of behavioral decisions in the leech.
Zur Modellierung und aktiven Schwingungsunterdrückung in Stahlwalzanlagen (On Modelling and Active Vibration Rejection in Steel Rolling Mills)
Authors: Schlacher Kurt , Holl Johann , Fuchshumer Stefan
Published: March 2005

Dieser Beitrag beschäftigt sich mit der systemtheoretischen Analyse und der aktiven Unterdrückung eines Vibrationsproblems bei (Stahl-) Walzanlagen, das unter der Bezeichnung Chatter bekannt ist. Als Grundlage für die Systemanalyse und den Reglerentwurf wird ein mathematisches Modell einer mehrgerüstigen Walzanlage vorgestellt, das speziell den Bandumformvorgang unter Berücksichtigung eines nicht kreisförmigen Kontaktbereiches zwischen Walze und Band sowie die Kopplung der Gerüste beschreibt. Anhand dieses Modells kann nachgewiesen werden, dass in Abhängigkeit des Betriebspunktes der Anlage eine mechanische Rückkopplung zur Instabilität des dynamischen Systems führen kann, womit auch der so genannte Dritte Oktav Chatter erklärt wird. Zu seiner aktiven Unterdrückung werden unter Berücksichtigung der wesentlichen Nichtlinearitäten des Systems zwei Regelungskonzepte vorgestellt, zum einen ein passivitätsbasierter Reglerentwurf und zum anderen eine Regelung basierend auf der Theorie der differentiellen Flachheit.