bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase transitions in the adsorbed molecular chains
Authors: Lykah Victor , Syrkin Evgen
Published: August 2006

Rotational excitations of molecular adsorbed layers are studied theoretically. Nonlinear dynamical equations are obtained with accounting of quadrupolar interactions between molecules and freezing of translational degrees of freedom. The equilibrium positions of the molecules are found to be experimentally observed structures with alternating rotational ordering of planar rotors along the direction to the nearest neighbor (for linear or square structures) under low temperature. Dynamical analysis gives an integral of motion (energy) of the chain that in the long-wave limit leads consequently to the existence of four phases. The first one corresponds to oscillations near equilibrium ordered states. The second phase corresponds to low-energy rotational excitations along ‘valleys’ (easy directions in the effective potential) that do not destroy strong correlations between molecules while structural data can show rotational disorder (melting). The third phase corresponds to an energy that is enough to travel between ‘valleys’; only some ‘islands’ in the angle space are forbidden. Complete destruction of correlation when the energy is over the peaks of the effective potential corresponds to the fourth phase. Therefore rotational melting is a complex phenomenon that has several stages.
Superconducting states of the cylinder with a single vortex in magnetic field according to the Ginzburg-Landau theory
Authors: Zharkov Gely
Published: August 2006

Self-consistent solutions of the nonlinear Ginzburg-Landau (GL) equations are investigated numerically for a superconducting (SC) cylinder, placed in an axial magnetic field, with a single vortex on the axis (m=1). Two modes, which show the original state of the cylinder, SC or normal (s
0 andn
0), are studied. The field increase (FI) and the field decrease (FD) regimes are studied. The critical fields destroying the SC state withm=1 are found in both regimes. It is shown that in a cylinder of radiusR and GL-parameter ϰ, there exist a number of solutions depending only on the radial co-ordinater corresponding to different states such as M,e, d, p,i, n,
$$\bar n$$
,n
*, and the state diagram on the plane of the variables (ϰ,R) is described. The critical fields corresponding to intrastate transitions and the onset of hysteresis are obtained. The critical fieldH
0(R) dividing the paramagnetic and diamagnetic states of the cylinder withm=1 is determined. The limiting fields of supercooling or superheating of the normal state at which the restoration of the SC state occurs are established. It is shown, that (in both casesm=1,0) there exist two critical parameters,
$$\kappa _0 = {1 \mathord{\left/ {\vphantom {1 {\sqrt 2 = 0.707}}} \right. \kern-\nulldelimiterspace} {\sqrt 2 = 0.707}}$$
and
$$\kappa _0 = 0.93$$
, which divide bulk SC into three groups (with
$$\kappa< \kappa _0 ,\kappa _0 \leqslant \kappa \leqslant \kappa _c $$
and
$$\kappa > \kappa _c $$
), in accordance with the behavior in a magnetic field. The parameters
$$\kappa _0 $$
and
$$\kappa _c $$
mark the boundary for the existence of a supercooled normal
$$\bar n$$
-state in FD-regime and a superheated SC M-state in FI-regime respectively. It is shown, that the value
$$\kappa _* = 0.417$$
, which was claimed in a number of papers as related to type-I superconductors, is illusory.
Specific solutions of the generalized Korteweg-de Vries equation with possible physical applications
Authors: Bracken Paul
Published: August 2006

Solutions for a type of generalized Korteweg-de Vries equation which should have physical impact will be determined here. These types of solutions should have applications in the study of intrinsic localized modes optical waveguide arrays and fluid dynamics. It is shown that trigonometric and hyperbolic solutions can be obtained by matching powers and coefficients of the independent terms in the equation after the assumed solution has been substituted. As well, solutions to the equation in terms of more complicated Jacobe elliptic functions are determined.
Study of relaxation processes in monomolecular films by the step compression experiment
Authors: Vajda Ján , Weis Martin , Baranĉok Drahoslav , Cirák Július , Tomćík Pavol
Published: August 2006

Maxwell's displacement current flowing through a metal electrode/air gap/Langmuir monolayer was detected. MDC experimental results obtained during a step compression mode are presented and contrasted with the Debye-Brown rotational model. As an alternative approach a theoretical model based on an analogy with a nonideal gas of polar molecules is derived from Lagrange's equation of motion.
A numerical solution of a two-dimensional transport equation
Authors: Martin Olga
Published: August 2006

In this paper we present a variational method for approximating solutions of the Dirichlet problem for the neutron transport equation in the stationary case. Error estimates from numerical examples are used to evaluate an approximation of the solution with respect to the steps of two grids.
Pseudo-MV algebra of fractions and maximal pseudo-MV algebra of quotients
Authors: Piciu Dana
Published: August 2006

The aim of this paper is to define the notions of pseudo-MV algebra of fractions and maximal pseudo-MV algebra of quotients for a pseudo-MV algebra (taking as a guide-line the elegant construction of complete ring of quotients by partial morphisms introduced by G. Findlay and J. Lambek-see [14], p.36). For some informal explanations of the notion of fraction see [14], p. 37. In the last part of this paper the existence of the maximal pseudo-MV algebra of quotients for a pseudo-MV algebra (Theorem 4.5) is proven and I give explicit descriptions of this MV-algebra for some classes of pseudo MV-algebras.
Representation of finite groups and the first Betti number of branched coverings of a universal Borromean orbifold
Authors: Toda Masahito
Published: August 2006

The paper studies the first homology of finite regular branched coverings of a universal Borromean orbifold called B
4,4,4ℍ3. We investigate the irreducible components of the first homology as a representation space of the finite covering transformation group G. This gives information on the first betti number of finite coverings of general 3-manifolds by the universality of B
4,4,4. The main result of the paper is a criterion in terms of the irreducible character whether a given irreducible representation of G is an irreducible component of the first homology when G admits certain symmetries. As a special case of the motivating argument the criterion is applied to principal congruence subgroups of B
4,4,4. The group theoretic computation shows that most of the, possibly nonprincipal, congruence subgroups are of positive first Betti number.
Affinely equivalent complete flat manifolds
Authors: Sadowski Michal
Published: August 2006

Let E
Aff(Γ,G, m) be the set of affine equivalence classes of m-dimensional complete flat manifolds with a fixed fundamental group Γ and a fixed holonomy group G. Let n be the dimension of a closed flat manifold whose fundamental group is isomorphic to Γ. We describe E
Aff(Γ,G, m) in terms of equivalence classes of pairs (ε, ρ), consisting of epimorphisms of Γ onto G and representations of G in ℝm-n. As an application we give some estimates of card E
Aff(Γ,G, m).
Hyperpolarizability of 6-vertex carboranes quantum chemical study
Authors: Suponitsky Kyrill , Timofeeva Tatiana
Published: August 2006

Structure and molecular first hyperpolarizability (β) of nitro-amino-substituted 6-vertex 1,6-carboranes are investigated by means of DFT calculations. The results obtained have revealed that the relative orientation of substituents with respect to the carborane cage influences bond lengths distribution in the cage, which leads to significant changes in the values of hyperpolarizabilities. Calculations with different basis sets have demonstrated that the value of β is not significantly affected by the choice of basis set. The calculated data shows that hyperpolarizability of carborane molecules substituted for carbon atoms is lower than when substituted for boron atoms. For latter molecule, the value of β is of the same order as that of para-nitroaniline molecule.
Epicatechin-copper 9II) complexes: Damage of small intestinal epithelium
Authors: Stavrescu Ruxandra , Kimura Takahide , Hayakawa Fumiko , Ando Takashi
Published: August 2006

Four epicatechins [(−)-epicatechin (EC), (−)-epicatechin gallate (ECg), (−)-epigallocatechin (EGC), (−)-epigallocatechin gallate (EGCg)] and their corresponding copper complexes were compared with regard to their effect on the viability of Caco-2 colon cancer cells in vitro, measured by 3-(4,5-dimethylthyazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay. The viability of Caco-2 cells exposed to EC (1 mM), ECg (1 mM) or EGC (1mM) respectively, for 30 min, was comparable to that of the saline control group, while EGCg (1 mM) apparently enhanced cellular activity. in contrast, the cells treated with epicatechin-copper complexes were killed. Bivalent copper 91 mM), in similar conditions, did not affect the cells. No cell leakage or other histological differences were observed, implying a rapid cell death. The suggested mechanism of killing is by OH radical attack, produced in the presence of epicatechin-copper complexes, but not in the presence of either of the epicatechins or copper alone. The reaction sites are discussed.
1,3-bis(2,4,6-trinitrophenylaminooxy)propane and its 4-cyano-2,6-dinitrophenyl congener: Synthesis and properties
Authors: Covaci Irina , Ionita Petre , Caproiu Miron , Socoteanu Radu , Constantinescu Titus , Balaban Alexandru
Published: August 2006

Starting from N-hydroxyphthalimide (5) and 1,3-dibromopropane (6) we obtained 1,3-bis(phthalimidooxy)propane (7) which led to 1,3-bis(aminooxy)propane dihydrochloride (8). From its reaction with picryl chloride or 4-cyano-2,6-dinitrochlorobenzene, the two title compounds (4b, 4a) were obtained.

1H-NMR and 13C-NMR spectra are presented. For comparison with the analogous N-methoxy-2,6-dinitro-4-R-anilines 1a, 1b (R=CN or R=NO2), wer report the hydrophobic characteristics (by RPTLC), electronic spectra for the neutral compounds and their anions, pKa values, and the behavior towards oxidizers (DPPH, PbO2, Pb(CH3COO)4, KMnO4 and Ag2O); DPPH converts compounds 1a, 1b and 4a, 4b into betainic structures 2a, 2b respectively.
Synthesis of vinca alkaloids and related compounds 991. A new heterocyclic system
Authors: Csókási Pál , Gács-Baitz Eszter , Szántay Csaba
Published: August 2006

Utilising our earlier intermediate obtained by the umpolung reactivity of quinolizidine enamines, a new heterocyclic system: (11bSR, 15aSR)-1,2,3,6,11,14,15,15a-Octahydro-5H-indolo [2′,3′:3,4]pyrido[2,1-j]-1,6-naphthyridin-13(12H)-one was synthesised and its biological effects evaluated. Although modest, significant and selective effects were detected.
Determination of imazalil by on-line coupled capillary isotachophoresis with capillary zone electrophoresis
Authors: Kvasnička František , Dobiáš Jaroslav , Klaudisová-Chudáčková Kamila
Published: August 2006

A simple, rapid and reproducible capillary isotachophoretic on-line coupled with capillary zone electrophoresis (CITP-CZE) method for the determination of IMz in food packaging extracts and its residues in apples is described. A good separation of the IMZ from other sample constituents was achieved within 15 minutes without any sample clean up. Method characteristics (linearity, accuracy, intra-assay and detection limit) were determined. Less amount of time involved, sufficient sensitivity and low running cost are the important attributes of CITP-CZE method.
Ab initio and infrared spectral study of 4′-substituted phenylthiolbenzoates
Authors: Ivanova Bojidarka , Arnaudov Michail
Published: August 2006

The geometry of the 4′-cyano-(4′-CNPTB) and the 4′-methoxy-(4′-MePTB) phenylthiolbenzoates were obtained by ab initio calculations employing 6–31G basis set at Hartee-Fock level of theory. The results predict an extended form of the molecules and torsional angle between the phenyl rings at 90.85(6)0 and 90.87(3)0, respectively. On the basis of vibrational analysis the frequency assignment was carried out. The calculated frequencies were compared with the experimental IR spectral data in carbon tetrachloride, carbon disulfide solutions and in solid state.
A study of background emissions enhancements in nitrogen afterglows, due to addition of discharged O2, in connection with the reactions {N2 (A3Σu+, υ) + O(3P)}, {O2 (a1Δg) + N(4S)} and {O2 (a1Δg) + N2 (A3Σu+)}
Authors: Kamaratos Efstathios
Published: August 2006

Intensity enhancement due to the addition of discharged O2 is examined for background N2 (B Πg → A3Σu+) emissions in various flowing nitrogen afterglows. Possible implications are reported for the experimentally determined rate constants for the reactions {N2 (A3Σu+, υ) + O(3P)}, and {O2 (a1Δg) + N(4S)}, as a result of the present study. The present, as well as previously reported, N2 (B Πg → A3Σu+) emissions intensity enhancements suggest complementary conclusions. Previous differences in experimental results reported for the {O2 (a1Δg) + N(4S)} reaction [based on studies observing the decay of either O2 (a1Δg) molecules or N(4S) atoms alone] are reconciled by a unifying additional interpretation. This interpretation leads to a rate constant estimate for the energy transfer reaction, {O2 (a1Δg) + N(2(A3Σu+)}, deduced to account for the above N2 (B3Πg → A3Σu+) emissions intensity enhancements.
Mechanistic investigations of oxidation of isatins by sodium N-chlorobenzenesulfonamide in alkaline medium: A kinetic study
Authors: Puttaswamy  , Jagadeesh R.
Published: August 2006

Oxidation of isatins (isatin, 5-methylisatin, 5-bromoisatin and 5-nitroisatin) to their anthranilic acids was performed efficiently with sodium N-chlorobenzenesulfonamide or chloramine-B (CAB) in alkaline medium at 35±0.1°C. The reactions follow identical kinetics for all the isatins, being first-order dependence each in [CAB]o and [Isatin]o and inverse fractional-order on [NaOH]. Addition of halide ions and benzenesulfonamide, reduction product of CAB, do not significantly affect the rate. Variation of ionic strength of the medium had no effect on the rate, while the dielectric effect is negative. The solvent isotope effect was studied using D2O. Activation parameters for the overall reaction have been computed. The rates satisfactorily correlate with the Hammett σ relationship and the reaction constant ρ is −0.31 signifies that electron releasing groups accelerate the reaction while the electron withdrawing groups retard the rate. Values of ΔH≠ and ΔS≠ are linearly related and an isokinetic relationship is observed with β=376 K, indicating the reaction is controlled by enthalpy. The stoichiometry of the title reaction is found to be 1∶1. Oxidation products of isatins were identified as their corresponding anthranilic acids and the yields were found to be around 90 %. The observed results have been explained by a plausible mechanism and the related rate law deduced. This method offers several advantages including high yield of the products, short reaction times, easier isolation of products, and stable, cost effective and relatively non-toxic reagents, which make the reaction process simple and smooth.
Determination of p-nitrobenzene-azo-naphthol by an oscillating chemical reaction using the analyte pulse perturbation technique
Authors: Gao Jinzhang , Sun Kanjun , Yang Wu , Zhou Huixian
Published: August 2006

A simple analytical method for the determination of p-nitrobenzene-azo-naphthol was proposed by a sequential perturbation with different amounts of p-nitrobenzene-azo-naphthol on an oscillating chemical system. The method involves a Cu(II)-catalysed oscillating reaction between hydrogen peroxide and sodium thiocyanate in alkaline medium with the aid of continuous-flow stirred tank reactor (CSTR). A good linear relationship between the changes, oscillation amplitude or/and period, and the concentration of p-nitrobenzene-azo-naphthol was obtained. The use of analyte pulse perturbation technique provides a possibility of sequential determination in a same oscillating system, due to a new steady state that reappeared rapidly after each perturbation. The calibration curve fits a linear equation very well when the concentration of p-nitrobenzene-azo-naphthol ranging from 5.2×10−7 to 3.3×10−3M. Influence of temperature, injection point, flow rate and reactants variables on this system were investigated in detail.
Synthesis, spectral characterization, redox and antimicrobial activity of Schiff base transition metal(II) complexes derived from 4-aminoantipyrine and 3-salicylideneacetylacetone
Authors: Raman Natarajan , Thangaraja Chinnathangavel , Johnsonraja Samuelraj
Published: August 2006

A novel tetradentate N2O2 type Schiff base, synthesized from 1-phenyl-2,3-dimethyl-4-aminopyrazol-5-one(4-aminoantipyrine) and 3-salicylidene-acetylacetone, forms stable complexes with transition metal ions such as CuII, NiII, CoII and ZnII in ethanol. Microanalytical data, magnetic susceptibility, IR, UV-Vis.,1H-NMR, ESR and Mass spectral techniques were used to confirm the structures. Electronic absorption spectra of the complexes suggest a square-planar geometry around the central metal ion. These complexes show higher conductance values, supporting their electrolytic nature. The monomeric nature of the complexes was confirmed from their magnetic susceptibility values. Cyclic voltammogram of the copper(II) and nickel(II) complexes in DMSO solution at 300 K were recorded and the results are discussed. The X-band ESR spectra of the copper complex were recorded and the molecular orbital coefficient values were calculated from the spectra. The in vitro antimicrobial activities of the investigated compounds were tested against bacteria such as Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis and Escherichia coli and fungi like Aspergillus niger and Rhizoctonia bataicola. Most of the metal chelates show higher antimicrobial activity for the above microorganisms than that of the free ligand.
Bioaccumulation study of acrylates in algae (Chlorella kessleri) by Py-GC and Py-GC/MS
Authors: Halás Ladislav , Oriňák Andrej , Sharif Abubaker , Ádámová Monika , Ladomerský Juraj
Published: August 2006

Acrylate monomers methylmethacrylate (MMA) and cyclohexylmethacrylate (CHMA) bioaccumulation has been determined in aquatic organism, algae (Chlorella kessleri). Algae were collected in amount of 0.4 mg and directly injected to the pyrolytical cell. In algae bodies accumulated monomers were analysed by pyrolysis gas chromatography (Py-GC) and pyrolysis gas chromatography coupled with mass spectrometry (Py-GC/MS). Traces of the accumulated monomers in algae body can be determined after 1-, 2-, 3-weeks of incubation. Maximum content of MMA was determined after 3-week of experiment, contrariwise in the case of CHMA after 2-week exposition. Relationship with pyrolysis temperature has also been studied.
Redundant wavelet processing on the half‐axis with applications to signal denoising with small delays: theory and experiments
Authors: Chaplais François , Tsiotras Panagiotis , Jung Dongwon
Published: August 2006

A wavelet transform on the negative half real axis is developed using an average‐interpolation scheme. This transform is redundant and can be used to perform causal wavelet processing, such as on‐line signal denoising, without delay. Nonetheless, in practice some boundary effects occur and thus a small amount of delay is required to reduce them. The effect of this delay is studied using a numerical example of a signal with large noise and sharp transients. It is shown that the delay required to obtain acceptable denoising levels is decreased by using the proposed redundant transform instead of a non‐redundant one. We also present results from the experimental implementation of the proposed algorithm for the denoising of a feedback signal during the control of a three‐phase permanent‐magnet synchronous brushless DC motor. Copyright © 2006 John Wiley & Sons, Ltd.
How do simple programs behave
Authors: Wolfram Stephen
Published: August 2006

Whereas once the world view of the ancient world was shifted by Pythagorean mathematics, scientific knowledge and human perception has been contested in the 21st century by developments in computation. In his ground‐breaking book Stephen Wolfram, the British physicist and creator of the Mathematica program, asserted that the complexity of the universe could be clearly understood in terms of simple programs. Here in an exclusive extract, Wolfram describes how one of the most straightforward programs, cellular automata, despite adhering to simple rules, yields some surprisingly complex results. Copyright © 2006 John Wiley & Sons, Ltd.
Metaphysics of genetic architecture and computation
Authors: Chu Karl
Published: August 2006

Karl Chu ruminates on the far‐reaching impact that the convergence of computation and biogenetics will have on the unfolding history of man and nature. Could the world be ‘moving into the so‐called Post‐Human Era, which will bring forth a new kind of biomachinic mutation of organic and inorganic substances’? How can architects reconfigure the practice of their discipline in order to meet the demands of this computational and biogenetic revolution? Copyright © 2006 John Wiley & Sons, Ltd.
Codes, eros and craft: an interview with Evan Douglis
Authors: Silver Mike
Published: August 2006

From a studio in Brooklyn, New York, Evan Douglis has carved out an international reputation for innovative research into self‐generative systems, membrane technology and contemporary fabrication. In the last decade, this work has largely been expressed through interactive installations, a medium that is compatible with Douglis's curatorial interests (he was the director of the architecture galleries at Columbia University for eight years). However, with the opening last year of the REptile, Haku Japanese Restaurant in New York, and the ongoing development of the REptile tile product line, Douglis is currently working at new building and manufacturing scales. As Chair of the Department of Undergraduate Architecture at the Pratt Institute since 2003, his influence on a generation of younger designers has been palpable. Here, guest‐editor Mike Silver discusses with Douglis the significance for him of the interface between the algorithmic and the material. Copyright © 2006 John Wiley & Sons, Ltd.
Colors restaurant
Authors: Merkel Jayne
Published: August 2006

One of the few good things to come out of the World Trade Center disaster was the Restaurant Opportunities Center of New York (ROC‐NY), a nonprofit organisation formed after 11 September to provide ongoing support to displaced workers and families of victims from the centre's Windows on the World restaurant. Now ROC‐NY has 700 members, is working to improve conditions for restaurant workers all over the city, and is helping displaced workers from all the World Trade Center restaurants open cooperatively owned restaurants of their own. Jayne Merkel describes the first, the ambitious Colors, which has 58 owners from 24 countries, most of whom once worked at the enormous Windows on the World at the top of the famous twin towers. Copyright © 2006 John Wiley & Sons, Ltd.
The Crown Liquor Saloon, Belfast
Authors: Peyton Jane
Published: August 2006

Jane Peyton, the author of Pub Scene, raises her glass and writes a eulogy in celebration of one of Britain's finest 19th‐century gin palaces: The Crown Liquor Saloon, which remained a ‘dowager’ in Belfast during the troubles. Copyright © 2006 John Wiley & Sons, Ltd.
Photoelectrochemical Reactivity of a Hybrid Electrode Composed of Polyoxophosphotungstate Encapsulated in Titania Nanotubes
Authors: Xie Y. B.
Published: August 2006

A polyoxometalate‐modified titania hybrid electrode with a tailored microstructure is studied for its photoelectrochemical applications. A highly ordered TiO2 nanotube array is prepared by low‐voltage anodization followed by calcination. Functionalized polyoxophosphotungstate–titania/titanium (POW–TiO2/Ti) hybrid electrodes are synthesized by encapsulating POW nanoaggregates in the TiO2 nanotube array. The morphological characteristics and structures of POW–TiO2 composites are examined by field‐emission scanning electron microscopy, X‐ray diffraction, energy dispersive X‐ray spectroscopy, and Fourier transform IR spectroscopy. The photoelectrochemical properties of the POW–TiO2/Ti electrodes are investigated by anodic polarization photocurrent‐response measurements. Photocatalytic/photoelectrocatalytic reactivities of microstructured and nanotubular POW–TiO2/Ti photoanodes are studied for their use in the degradation of recalcitrant organic pollutants.
Early childhood stress and adult age mortality—A study of dental enamel hypoplasia in the medieval Danish village of Tirup
Authors: Boldsen Jesper L.
Published: August 2006

This study explores how linear enamel hypoplasia (LEH) affects mortality in the village of Tirup (A.D. 1150–1350), Denmark. Data consist of information on 583 skeletons aged 1 year or more. Three partly overlapping subsamples were defined. (1) 104 skeletons of young children aged 1–6 years and 120 skeletons of adults giving information on LEH. (2) 458 skeletons aged 6 years or more. (3) 109 adult skeletons (aged 20 years or more) that provided transition analysis age estimates, sex assessments, and LEH information. Of the 109 skeletons in Subsample 3, 60 had no and 49 had at least one LEH. In Subsample 1, it was found that the case fatality rate for episodes potentially leading to LEH dropped from over 0.5 in 1‐year olds to around 0.1 in 3–5‐year olds. Only models with heterogeneity of frailty could describe late childhood and adolescent mortality. Further, it was shown that only a model with continuously varying frailty preserved heterogeneity to adulthood. Among young adult females and males in all adult ages, people with LEH experienced a higher mortality than people without it. Among males, the mortality rate ratio (MRR) was 2.28. The analyses indicate that the MRR gives an unbiased estimate for the extra risk of dying for adult males with LEH. The values of the case fatality rates for young children might be slightly biased upward because of a higher than average number of older children and adolescents dying with LEH. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.
Biosynthetische anorganische Chemie
Authors: Lu Yi
Published: August 2006

Anorganische Chemie und Biologie können sehr voneinander profitieren. Nachdem anorganische Synthese und physikalische Chemie zu den großen Erfolgen bei der Aufklärung der Rolle von Metallionen in biologischen Systemen beigetragen haben, sollen nun biologische Systeme bei der Weiterentwicklung der Koordinationschemie helfen. Ein Beispiel dafür sind kleine, stabile, leicht herstellbare und gut charakterisierte Proteinliganden für die Synthese neuer anorganischer Verbindungen. Diese “biosynthetische anorganische Chemie” wird erst dank einiger Entwicklungen in der Biologie möglich. Der Aufsatz beginnt mit Fortschritten bei der Synthese genauer Modelle von komplexen Metalloproteinen. Anschließend wird gezeigt, wie das Konzept für anorganische Chemie ebenso wie Biologie neuartige Verbindungen hervorbringen kann. Im Vordergrund stehen “Synthesetricks”, die von biologischen Systemen erlernt wurden, sowie neue Strukturen.
Spatial distribution of fishing effort in relation to seafloor habitats in the Kattegat, a GIS analysis
Authors: Nilsson Per , Ziegler Friederike
Published: August 2006

High‐resolution fishing effort data from the Kattegat, an important fishing ground for Swedish and Danish fishermen, was analysed in a Geographical Information System (GIS). Data were based on position data for individual tows reported by Swedish fishermen during 2001–2003.

Gear dimension and towing speed data were used to calculate an index for area swept per hour for each main gear type in use in the area. These indexes were multiplied by fishing effort and a grid theme of fishing intensity was created after GIS analysis.

Around 44% of the entire area was affected by Swedish fisheries during the study period, hence 56% was not affected.

Effort was highly concentrated in certain areas and 10% of the total area was covered more than twice per year.

Overlaying the effort data set with habitat maps classified according to the European Nature Information System (EUNIS) showed that the fishing pressure differed between habitats. For deep rocky and muddy habitats, almost the entire area was affected by fisheries during the study period, while both intensity and proportion affected were lower in sandy sediments and gravels.

Around 55% of the deep rocky habitats were trawled more than twice per year. Of the muddy seafloor areas, 41% were covered more than twice per year and 4% more than once a month by trawls.

The biological effects of the fishing intensities found were analysed using a database (MarLIN) containing assessments of marine habitat recoverability. All habitats except muds are probably in a nearly or fully recovered condition (as defined by MarLIN). A considerable part of the muddy habitats are in a permanently altered condition owing to fishing disturbance taking place more frequently than the indicated recovery time.

Danish fishermen report more fishing effort in the area than do Swedes. Owing to differences in reporting fishing positions, Danish fisheries could not be included in the present study. Scaling up the results to include Danish fisheries is discussed.

The results of the present study could be used to target habitat management goals more precisely, while minimizing the negative impact of restrictions on the fishing sector.

A prerequisite for performing similar studies is the availability of high‐resolution fishing effort data and high‐resolution benthic habitat maps.

Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of Substituted 1,3‐Diene Synthetic Equivalents by a Ru‐Catalyzed Diyne Hydrative Cyclization
Authors: Trost Barry M. , Huang Xiaojun
Published: August 2006

Catalyzed by [CpRu(CH3CN)3]PF6, the hydrative cyclization of dipropargylic sulfone substrates provides an effective way to synthesize highly functionalized substituted 3‐sulfolenes. The amount of water is crucial for the reactivity of this cycloisomerization reaction. The scope and limitations of the Ru‐catalyzed cycloisomerization are discussed. A marked ketone‐directing effect was observed for the first time in ruthenium‐catalyzed cyclizations. A plausible mechanism for the ketone‐directed cycloisomerization is also rationalized. The utility of this method was demonstrated by both sulfur dioxide extrusion of the 3‐sulfolenes to afford 1,3‐dienes and subsequent inter‐ or intramolecular Diels–Alder reactions.
Combining Treatment Selection and Definitive Testing
Authors: Proschan Michael A. , Hunsberger Sally A.
Published: August 2006

This is a discussion of the following two papers appearing in this special issue on adaptive designs: ‘An adaptive hierarchical test procedure for selecting safe and efficient treatments’ by Franz König, Peter Bauer and Werner Brannath, and ‘An adaptive two‐stage design with treatment selection using the conditional error function approach’ by Jixian Wang. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of particle size based separation of milled corn stover on AFEX pretreatment and enzymatic digestibility
Authors: Chundawat Shishir P.S. , Venkatesh Balan , Dale Bruce E.
Published: August 2006

Particle size and compositional variance are found to have a substantial influence on ammonia fiber explosion (AFEX) pretreatment and enzymatic hydrolysis of lignocellulosic biomass. Corn stover was milled and fractionated into particle sizes of varying composition. The larger particle size fractions (rich in corn cob and stalk portions) were found to be more recalcitrant to hydrolysis compared to the smaller size fractions (rich in leaves and husk portion). Electron spectroscopy for chemical analysis (ESCA) and Fourier transform infrared spectroscopy (FTIR) were used for biomass surface and bulk compositional analysis, respectively. The ESCA results showed a 15–30% decrease in the O/C (oxygen to carbon) ratio after the pretreatment indicating an increase in the hydrophobic nature of biomass surface. FTIR results confirmed cleavage of the lignin–carbohydrate complex (LCC) for the AFEX‐treated fractions. The spectroscopic results indicate the extraction of cleaved lignin phenolic fragments and other cell wall extractives to the biomass surface upon AFEX. Water washing of AFEX‐treated fractions removed some of the hydrophobic extractives resulting in a 13% weight loss (dry weight basis). Phenolic content of wash stream was evaluated by the modified Prussian blue (MPB) method. Removal of ligno‐phenolic extractives from the AFEX‐treated biomass by water washing vastly improved the glucan conversion as compared to the unwashed samples. Reduction in substrate particle size was found to affect the AFEX process and rate of hydrolysis as well. Implications of the stover particle size, composition, and inhibitory role of the phenolic fragments on an integrated biorefinery are discussed. Biotechnol. Bioeng. 2007;96: 219–231. © 2006 Wiley Periodicals, Inc.
A study on the mediating role of disgust with meat in the prediction of red meat consumption among young females
Authors: Kubberød Elin , Ueland Øydis , Risvik Einar , Henjesand Inge Jan
Published: August 2006

Recent studies have examined young females' negative sentiments toward meat in the western world. This paper explored the role of various factors that may trigger disgust with meat and hence avoidance of red meat among young females. These include negative body esteem, disgust motivations related to ideational concerns, sensory‐affective concerns, and anticipation of negative consequences relating to the consumption of meat. The investigation showed that all of these factors were positively related to disgust with meat, and disgust with meat influenced red meat consumption negatively.

Copyright © 2006 John Wiley & Sons, Ltd.
Consumption and community: choices for women over forty
Authors: Szmigin Isabelle , Carrigan Marylyn
Published: August 2006

Women in their 40s face a range of issues regarding how they choose to present themselves to the world; often these choices involve forms of consumption. We talked to two groups of British women and discussed how they felt about themselves and the pressures upon them. We present a discussion which aims to synthesize some of the key features of how these women face their futures and suggest potential theoretical positions to help encapsulate women's present and future selves. We suggest that there are a number of pressures that may engender alternative consumption choices and these are often set within a wider sense of female community. The concept of community should prove useful for further theorising on women's future consumption choices.

Copyright © 2006 John Wiley & Sons, Ltd.
Positive vs. negative switching barriers: the influence of service consumers' need for variety
Authors: Vázquez‐Carrasco Rosario , Foxall Gordon R.
Published: August 2006

In this study, we deal with the existing debate related to the establishment of switching barriers retaining customers in the relationship with a provider. In particular, we demonstrate that ‘positive’ switching barriers (relational benefits) play a greater role that the ‘negative’ ones (switching costs and availability and attractiveness of other providers' offers) in determining customer satisfaction and retention. On the other hand, we include customers' need for variety in the proposed model, in order to demonstrate that a higher level of this psychological trait will lead to a lower perception of the existence of switching barriers. The hypotheses proposed have been tested for a services context on a sample of 800 individuals, using the technique ‘Partial Least Squares’ (PLS). Our findings lead to some interesting managerial implications.

Copyright © 2006 John Wiley & Sons, Ltd.
Head‐to‐Head Cross‐Linked Adduct between the Antitumor Unit Bis(μ‐N,N′‐di‐p‐tolylformamidinato)dirhodium(II,II) and the DNA Fragment d(GpG)
Authors: Chifotides Helen T. , Dunbar Kim R.
Published: August 2006

Reactions of the compound cis‐[Rh2(DTolF)2(CH3CN)6](BF4)2, a formamidinate derivative of the class of antitumor compounds [Rh2(O2CR)4] (R=Me, Et, Pr), with 9‐ethylguanine (9‐EtGuaH) or the dinucleotide d(GpG) proceed by substitution of the acetonitrile groups, with the guanine bases spanning the RhRh bond, in a bridging fashion, through sites N7/O6. In the case of 9‐EtGuaH, both head‐to‐head (HH) and head‐to‐tail (HT) isomers are formed, whereas with the tethered bases in d(GpG), only one right‐handed conformer HH1R [Rh2(DTolF)2{d(GpG)}] is present in solution. For both cis‐[Rh2(DTolF)2(9‐EtGuaH)2](BF4)2 and [Rh2(DTolF)2{d(GpG)}], the absence of N7 protonation at low pH and the substantial decrease of the pKa values for N1‐H deprotonation, support N7/O6 binding of the bases to the dirhodium core. The N7/O6 binding of the bases is further corroborated by the downfield shift by Δδ∼4.0 ppm of the 13C NMR resonances for the C6 nuclei as compared to the corresponding resonances of the free ligands. The HH arrangement of the guanine bases in [Rh2(DTolF)2{d(GpG)}] is indicated by the intense H8/H8 ROE cross‐peaks in the 2D ROESY NMR spectrum. Complete characterization of the [Rh2(DTolF)2{d(GpG)}] conformer by 2D NMR spectroscopy supports anti‐orientation and N (C3′‐endo) conformation for both deoxyribose residues. The N‐pucker for the 5′‐G base is universal in such cross‐links, but it is very unusual for platinum and unprecedented for dirhodium HH cross‐linked adducts to have both deoxyribose residues in the N‐type conformation. The bulk, the nonlabile character, and the electron‐donating ability of the formamidinate bridging groups spanning the dirhodium core affect the nature of the preferred dirhodium DNA adducts. Molecular modeling studies performed on [Rh2(DTolF)2{d(GpG)}] corroborate the structural features obtained by NMR spectroscopy.
Noninvasive magnetic resonance thermography of soft tissue sarcomas during regional hyperthermia
Authors: Gellermann Johanna , Hildebrandt Bert , Issels Rolf , Ganter Hildegard , Wlodarczyk Waldemar , Budach Volker , Felix Roland , Tunn Per‐Ulf , Reichardt Peter , Wust Peter
Published: August 2006

BACKGROUND

The objective of this study was to evaluate noninvasive magnetic resonance (MR) thermography for the monitoring of regional hyperthermia (RHT) in patients with soft tissue sarcomas of the lower extremities and pelvis.

METHODS

Noninvasive MR monitoring during RHT was performed in 9 patients who had high‐risk soft tissue sarcomas of the lower extremities or pelvis during neoadjuvant chemotherapy plus RHT in the scope of the European Organization for Research and Treatment of Cancer 62961/European Society for Hyperthermic Oncology RHT‐95 study. Anatomic and temperature‐sensitive data sets were acquired every 10 minutes before and during RHT (using gradient‐echo‐sequences with variable echo times). MR temperature distributions were derived from the phase differences by using the proton‐resonance frequency shift method. A phase convolution setting phase shifts to zero in the fat tissue was performed as a drift correction. The mean MR temperatures in the tumor and muscles and the index temperatures (e.g., T90, which covers 90% of the target volume) and thermal doses were determined and compared with pathohistologic responses and direct temperature measurements if available.

RESULTS

Thirty of 72 MR‐thermography data sets (>40% of heat sessions) were evaluable. A significant correlation was observed between pathohistologic response (defined as a necrosis rate ≥90%) and standardized thermal parameters, such as thermal dose cumulative equivalent minutes at 43°C to 90% of the target volume (T90) (P = .050), mean T90 (P = .048), or T50 (P = .050). The correlation of 13 conventional temperature measurements performed in selected patients and sessions invasively in the tumor or noninvasively in rectum and bladder revealed an excellent correlation with MR temperatures (R2 = .96).

CONCLUSIONS

Noninvasive MR thermography of soft tissue sarcoma was feasible and suitable for validating the quality of heating during RHT. Cancer 2006. © 2006 American Cancer Society.
Characterization of O2–CeO2 Interactions Using In Situ Raman Spectroscopy and First‐Principle Calculations
Authors: Choi Y. M. , Abernathy Harry , Chen Hsin‐Tsung , Lin M. C. , Liu Meilin
Published: August 2006

Interactions between O2 and CeO2 are examined experimentally using in situ Raman spectroscopy and theoretically using density‐functional slab‐model calculations. Two distinct oxygen bands appear at 825 and 1131 cm−1, corresponding to peroxo‐ and superoxo‐like species, respectively, when partially reduced CeO2 is exposed to 10 % O2. Periodic density‐functional theory (DFT) calculations aid the interpretation of spectroscopic observations and provide energetic and geometric information for the dioxygen species adsorbed on CeO2. The O2 adsorption energies on unreduced CeO2 surfaces are endothermic (0.91<ΔEads<0.98 eV), while those on reduced surfaces are exothermic (−4. 0<ΔEads<−0.9 eV), depending on other relevant surface processes such as chemisorption and diffusion into the bulk. Partial reduction of surface Ce4+ to Ce3+ (together with formation of oxygen vacancies) alters geometrical parameters and, accordingly, leads to a shift in the vibrational frequencies of adsorbed oxygen species compared to those on unreduced CeO2. Moreover, the location of oxygen vacancies affects the formation and subsequent dissociation of oxygen species on the surfaces. DFT predictions of the energetics support the experimental observation that the reduced surfaces are energetically more favorable than the unreduced surfaces for oxygen adsorption and reduction.
Kinetics and Thermodynamics of Halide and Nitrite Oxidation by Mammalian Heme Peroxidases
Authors: Arnhold Jürgen , Monzani Enrico , Furtmüller Paul G. , Zederbauer Martina , Casella Luigi , Obinger Christian
Published: August 2006

The human heme peroxidases myeloperoxidase (MPO),eosinophil peroxidase (EPO) and lactoperoxidase (LPO) are able to oxidise (pseudo)halides and nitrite to reactive species that participate in host defence against foreign microorganisms as well as in immunomodulation and tissue degradation in certain pathologies. The heme in EPO and LPO is covalently linked to the apoprotein by two ester bonds, whereas in MPO it is additionally linked by a unique sulfonium ion bond to a methionine residue. As a consequence, the prosthetic group in MPO is significantly distorted from a planar conformation. These structural differences are reflected by distinct spectral and redox properties as well as reactivities toward chloride, bromide, iodide, thiocyanate and nitrite, which function as endogenous two‐ and one‐electron donors for these enzymes in vivo. Standard reduction potentials at pH 7 have been determined for all redox couples involved in the halogenation and peroxidase cycle of MPO and LPO and partially of EPO. A detailed thermodynamic analysis of the formation of reactive halide species by MPO and EPO was also performed. Thus, for the first time, a comprehensive analysis of reactions catalysed by human heme peroxidases is presented that allows a better understanding of their role in physiological and pathophysiological processes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Quantum Chemical Analysis of the Enantiomerisation Mechanism of Complexes of the Type [MII(XU)4]F+(M = Pt, Pd, Ni; X = S, Se, Te;U = urea)
Authors: Puchta Ralph , Meier Roland , van Eikema Hommes Nico J. R. , van Eldik Rudi
Published: August 2006

The enantiomerisation pathway for {[Pt(thiourea)4]}F+[a model for theC4‐symmetric [Pt(SU)4]SiF6(SU = thiourea) complex] and derivatives is explored by density functional theory (B3LYP/LANL2DZp) und the activation barrier for the one‐step process fromC4toC4′ via aC4transition state is computed. The substitution of Pt2+by Pd2+and Ni2+and the exchange of selenourea and tellurourea increase the barrier. ({[Pt(thiourea)4]}F+: 4.2 kcal/mol, {[Pd(thiourea)4]}F+: 4.5 kcal/mol, {[Ni(thiourea)4]}F+: 7.6 kcal/mol, {[Pt(selenourea)4]}F+: 5.3 kcal/mol, {[Pt(tellurourea)4]}F+: 8.8 kcal/mol). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Biological Evaluation of the Trifluoromethyl Analog of (4S)‐4,5‐Dihydroxy‐2,3‐pentanedione (DPD)
Authors: Frezza Marine , Balestrino Damien , Soulère Laurent , Reverchon Sylvie , Queneau Yves , Forestier Christiane , Doutheau Alain
Published: August 2006

The asymmetric synthesis of the trifluoromethyl analogue of (4S)‐4,5‐dihydroxy‐2,3‐pentanedione [(4S)‐DPD], the metabolic precursor of the bacterial quorum sensing (QS) autoinducer AI‐2, is described. The trifluoromethyl group was introduced by treating (trifluoromethyl)trimethylsilane with an α‐methylene ester resulting from a Baylis–Hillman reaction between (tert‐butyldimethylsilyloxy)acetaldehyde and a vinylamide derived from Oppolzer’s sultam reagent. The α‐diketonic moiety is formed during the last step by reductive ozonolysis of the hemiketal form of an α‐methylene trifluoromethyl ketone. Biological evaluation shows that this analogue is a weaker inducer of QS in Vibrio harveyi bacteria than DPD. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A semi‐analytical solution for groundwater responses to stream‐stage variations and tidal fluctuations in a coastal aquifer
Authors: Kim Kue‐Young , Kim Taehee , Kim Yongje , Woo Nam‐Chil
Published: August 2006

A two‐dimensional semi‐analytical solution to analyse stream–aquifer interactions in a coastal aquifer where groundwater level responds to tidal effects is presented. The conceptual model considered is a two‐dimensional subsurface system with stream and coastline boundaries at right angles. The dimensional and non‐dimensional boundary value problems were solved for water level in the aquifer by successive application of Laplace and Fourier transform techniques, and the results were obtained by numerical inversion of the transformed solution. The solution was then verified by reducing the solutions to one‐dimensional known problems and comparing the results with those from previous studies. Hypothetical examples were used to examine the characteristics of water‐level variations due to the variations in stream stage and the fluctuations in tide level. Sensitivity analysis indicated that streambed leakance has no influence over the amplitude of groundwater fluctuations, but that the effect of stream stage increases with increasing leakance. Little difference was observed in the water level for different aquifer penetration ratios with narrow stream width. Increases in streambed leakance caused increases in the effect of aquifer penetration by the stream on the water level. An increased specific yield value resulted in decreased amplitude of water fluctuations and mean water level, and showed that water‐level variations due to stream and tidal boundaries are sensitive to specific yield. Copyright © 2006 John Wiley & Sons, Ltd.