bluuebunny/crossref_metadata_2025 huggingface dataset:
The effectiveness of some compounds derived from antifouling paints in promoting imposex in Nassarius reticulatus
Authors: Barroso C.M. , Reis-Henriques M.A. , Ferreira M.S. , Moreira M.H.
Published: October 2002

Adult Nassarius reticulatus were exposed for two to three months to dissolved tributyltin (TBT), dibutyltin (DBT), triphenyltin (TPT) and diphenyltin (DPT) chlorides and to copper sulphate (CuSO4) in order to study the effectiveness of these compounds to induce imposex (penis and vas deferens development). The dialkyltins and copper did not promote imposex under exposure to 500 ng Sn l−1 and 500 ng Cu l−1. However, dissolved nominal concentrations varying between 100 and 500 ng Sn l−1 of TBT or TPT induced imposex in, respectively, 22 to 43% and 24 to 44% of the females. The testosterone titres of females increased significantly after two months' exposure to 250 ng Sn l−1 of TPT and TBT and the same happened to males exposed to 100 and 250 ng TPT-Sn l−1 and to 250 ng TBT-Sn l−1.
The prevalence of Hematodinium in Nephrops norvegicus from the western Irish Sea
Authors: Briggs R.P. , McAliskey M.
Published: October 2002

Infection of Nephrops norvegicus by a dinoflagellate parasite belonging to the genus Hematodinium, is reported in populations of Nephrops from the Irish Sea. Diseased animals are recognized by an opaque vivid body colour and high densities of parasites in the haemolymph. Infection causes a general morbidity of the host along with a reduction in swimming performance, which eventually leads to the death of the host lobster. Research vessel cruises performed over the period 1994–2001 have shown Hematodinium to occur in populations of Nephrops from the Irish Sea throughout this period. High infection prevalence during the month of April and negligible levels during October agree with published data on seasonal infection levels in Scottish Nephrops stocks. Data on spatial and temporal infection prevalence are presented for the first time for the Irish Sea and show variation between stations and between years. Mean infection prevalence peaked at 18% of captured Nephrops during April 1996 and was followed by a downward trend to 2001. Infection predominates in small Nephrops (<30 mm carapace length) and in females is normally associated with immature animals. Although a positive correlation with seawater salinity was noted, preliminary analysis did not show a relationship between prevalence and other environmental factors.
Effects of sponge encrustation on the swimming behaviour, energetics and morphometry of the scallop Chlamys hastata
Authors: Donovan Deborah A. , Bingham Brian L. , Farren Heather M. , Gallardo Rodolfo , Vigilant Veronica L.
Published: October 2002

The effect of sponge encrustation on swimming ability of Chlamys hastata was determined by investigating swimming behaviour, scallop morphometry, and energy expended during swimming with and without commensal epibionts. Scallops swam significantly longer after sponge encrustation was removed from their shells, but no significant differences were detected in swimming elevation or distance. Scallops with sponge encrustation showed no adductor muscle hypertrophy or changes in shell morphometry compared to scallops without encrustation. However, C. hastata did exhibit scaling relationships associated with maximizing swimming efficiency. Specifically, shell width and adductor muscle mass were positively allometric with shell height, while shell mass was negatively allometric with shell height. Scallops increased their energy expenditure (both aerobic and anaerobic) during valve-clapping, but no significant difference was detected between unencrusted (43·0 μmol adenosine triphosphate [ATP] consumed during a two min escape swim) and sponge-encrusted (40·0 μmol ATP) scallops. Scallops in both treatments derived 86% of the energy used for swimming from anaerobic sources. The lack of substantial differences between scallops with and without commensal sponges is partially explained by the observation that even heavy sponge encrustation increases the immersed weight of the scallop by only 5%. The presence of a sponge encrustation does not appear to inhibit swimming by this scallop species.
Shell morphology in Cerastoderma spp. (Bivalvia: Cardiidae) and its significance for adaptation to tidal and non-tidal coastal habitats
Authors: Mariani Stefano , Piccari Fabrizio , De Matthaeis Elvira
Published: October 2002

Several morphological characteristics of the shell in cockles (genus Cerastoderma) were investigated. A significant inverse relationship between rib number and shell curve was revealed in Cerastoderma glaucum. Morphometric and meristic descriptors were correlated with some environmental factors, such as salinity and temperature. Analysis of allometry in C. glaucum and Cerastoderma edule revealed significant differences between the two species. The results are discussed from an adaptive perspective, providing possible hypotheses on the steps which might have driven the evolution of form of the studied species during the process of adaptation to coastal tidal and confined habitats.
Range extension of three lessepsian migrant fish (Fistularia commersoni, Sphyraena flavicauda, Lagocephalus suezensis) in the Mediterranean Sea
Authors: Bilecenoglu Murat , Taşkavak Ertan , Kunt K. Bogaç
Published: October 2002

Two Red Sea immigrant fish species, Fistularia commersoni (Fistularidae) and Sphyraena flavicauda (Sphyraenidae), are reported for the first time from the Anatolian coast (Turkey) and for the second time from the Mediterranean Sea. Occurrence of Lagocephalus suezensis (Tetraodontidae) at the southern Turkish coast is substantiated and a new record of this species in the Aegean Sea is presented.
Foraging behaviour and feeding success of the black‐necked stork (Ephippiorhynchus asiaticus) in Dudwa National Park, Uttar Pradesh, India
Authors: Maheswaran Gopinathan , Rahmani Asad R.
Published: October 2002

Foraging behaviour of the black‐necked stork (BNS) Ephippiorhynchus asiaticus was studied in 1996 and 1997 in Dudwa National Park (DNP), Uttar Pradesh, India. The storks were observed using tactile and visual techniques to catch fish. Of the 929 fish seen caught in 2 years, 894 (96%) were caught by a tactile mode of feeding and the remaining 35 (4%) by a visual mode of feeding. The rate of foraging attempts by BNS fluctuates with that of season in DNP and coincides with prey abundance. Immediately after the monsoon when the water level was high, BNS had to search for prey more often, as the prey became widespread. Whereas in summer when the water level decreased, the concentration of the fish was higher, which helps BNS to catch fish in quick succession. Prey behaviour and the condition of the wetland determined the selection of the tactile foraging technique among the BNS in DNP. The black‐necked storks were more successful in the early hours of the day (06:00–10:00) and they were generally more successful or preferred to feed on medium‐sized fish (i.e. 5–10 cm) in DNP. Prey profitability was highest for larger size fish and decreased as the prey size decreased. Principal component analysis showed that prey size, handling time of each prey, the month and water depth determined foraging success in 1996 and 1997.
Anabolic agents in frail elderly patients
Authors: Hubbard Ruth , Pierce Andrew
Published: October 2002

Use of the term frailty in the medical literature has increased significantly in the last 20 years. A MEDLINE search using the combined terms ‘frail’ and ‘elderly’ yielded 473 articles published between 1996 and 2001, compared with 85 between 1980 and 1985. This increasing interest in frailty has been fuelled by evidence that the ‘frail elderly’ are the group most likely to benefit from geriatric intervention programmes and
by the close links between frailty and longer
hospital stays, nursing home utilization and
mortality.
Respite care
Authors: Vetter Norman J
Published: October 2002

Elderly people and their carers are not homogeneous groups, but are highly diverse in terms of their age, ethnicity, income, housing, education, geographical location and access to providers of health. In planning provision, particularly respite care, we need to focus attention on the needs and preferences of those who are not currently receiving help, as well as on the satisfaction with existing services of those who are. There been evidence for some years, for instance, that those in rural areas have different needs from those in urban areas.
Percutaneous Freehand™ System Intramuscular Electrode Placement
Authors: HAUSMAN M. R. , MASTERS J. E.
Published: October 2002

The FreeHand™ (NeuroControl Corporation, USA) system is an implantable electronic neuroprosthesis designed to stimulate muscles of tetraplegic upper limbs to achieve lateral pinch and simple grasp. When first introduced, the system required insertion through multiple large incisions, but recently introduced intramuscular electrodes have allowed the development of a percutaneous electrode placement technique. The technique minimizes incisions, decreases overall operative time and patient morbidity and improves the outcome by minimizing tendon adhesions.
The Distribution of Solitary Enchondromata at the Hand
Authors: GAULKE R.
Published: October 2002

The location of 327 solitary enchondromata of the hand reported in the English and German medical literature and 30 solitary enchondromata treated at our hospital was studied. Four were located in the carpus, 70 in the metacarpals and 283 in the phalanges. There were highly significant preferences for involvement of the proximal phalanges and the little finger ray. The proximal phalanx of the little finger was the most commonly involved bone.
Simple Curettage without Bone Grafting for Enchondromata of the Hand: With Special Reference to Replacement of the Cortical Window
Authors: GOTO T. , YOKOKURA S. , KAWANO H. , YAMAMOTO A. , MATSUDA K. , NAKAMURA K.
Published: October 2002

We studied 23 patients (25 bones) with enchondromata of the hand which were treated with simple curettage without bone grafting. The cortical window was replaced in 18 bones (group A), whereas it was not replaced in six bones (group B). In one bone, only half of the cortical window was replaced. Local recurrence was not seen in any patient. Although bone grafting was not performed, new bone formation was observed in all the patients. Radiographic and functional results were excellent in most bones. Restoration of the continuity of the cortex was seen at 3 (range, 1.5–4) months in group A and 8 (range, 6–12) month s in group B. This restoration is important for the recovery of mechanical strength and we therefore consider that the cortical window should be replaced, unless this is impractical.
Measurements of magnetic field fluctuations using an array of Hall detectors on the TEXTOR tokamak
Authors: Ďuran I. , Stöckel J. , Mank G. , Finken K. H. , Fuchs G. , Oost G. Van
Published: October 2002

Hall detectors have been used to measure the magnetic field together with its’ fluctuations in the boundary of a tokamak. The results show, that the measurements which have been performed so far, mainly by use of coils together with subsequent integration, either on-line or later by computer, can be substituted by Hall probe measurements giving the desired value of B directly. Because the integration of the coil signal becomes more and more difficult with long pulses, Hall detectors may give advantages in future fusion devices. We implemented a stack of nine Hall detectors mounted on three planes on a rod in such a way, that the three components of the magnetic field can be measured. To avoid capacitive and charge pickup from the plasma, the probes are electrically shielded. The damping due to skin effect within this shield has been taken into account. The probes have been calibrated using a known magnetic field of a straight wire driven with a LC bank. This field has been precisely measured with a Rogowski coil. The dependence of the Hall coefficient on the frequency has been measured and the pickup in the feeds due to Ḃ has been withdrawn from the results. We demonstrate the method with measurements on the TEXTOR tokamak, where we could clearly detect the small stray fields associated with magnetohydrodynamic (MHD) fluctuations. On TEXTOR we have been able to detect the MHD activity preceding discharge disruptions as well as the precursors of the so called sawteeth. The results are compared to those of other diagnostics on TEXTOR as, e.g., magnetic loops and electron cyclotron emission, and they do well compare.
Electrical resistivity of steels and face-centered-cubic iron
Authors: Bohnenkamp Ulrich , Sandström Rolf , Grimvall Göran
Published: October 2002

Literature data for the electrical resistivity of austenitic and ferritic steels are analyzed in a model that takes into account their composition and microstructure. The resistivity in these systems is so high that one must allow for its saturation. That effect is described with the shunt-resistor model, and saturation at 1.68 μΩm. Our analysis yields the contributions to the resistivity of austenite per weight percent from the solute elements N, C, Nb, Si, Ti, Cu, Ni, Cr, and Mo, with the contribution decreasing in this order. For ferrite, the contribution of the solute elements Si, Mn, Cu, Ni, Mo, and Cr was determined, with the contribution decreasing in this order. The data allow us to obtain the previously unknown resistivity of metastable pure γ-iron (fcc Fe) near room temperature, and find an interpolation formula for the resistivity up to 1183 K where the γ phase becomes stable. The resistivity in metastable γ-iron is significantly larger than the resistivity in stable α-Fe (bcc Fe) below 1000 K. This difference is attributed to a strong electron scattering due to spin disorder in γ-iron at intermediate temperatures.
Transport in random quantum dot superlattices
Authors: Gómez I. , Domínguez-Adame F. , Diez E. , Orellana P.
Published: October 2002

We present a model based on the two-dimensional transfer matrix formalism to calculate single-electron states in a random wide-gap semiconductor quantum dot superlattice. With a simple disorder model both the random arrangement of quantum dots (configurational disorder) and the spatial inhomogeneities of their shape (morphological disorder) are considered. The model correctly describes channel mixing and broadening of allowed energy bands due to elastic electron scattering by disorder.
Surface control of optical properties in silicon nanoclusters
Authors: Puzder Aaron , Williamson A. J. , Grossman Jeffrey C. , Galli Giulia
Published: October 2002

Density functional and quantum Monte Carlo calculations are employed to determine the effect of surface passivants on the optical gap of silicon nanoclusters. Our results show that quantum confinement is only one mechanism responsible for visible photoluminescence and that the specific surface chemistry must be taken into account in order to interpret experimental results. Significant changes occur in the optical gap of fully hydrogenated silicon nanoclusters when the surface contains passivants that change the bonding network at the surface. In the case of just one double-bonded oxygen atom, the gap reduction computed as a function of the nanocluster size demonstrates that one contaminant can greatly alter the optical gap. A further significant reduction of the gap occurs with multiple double-bonded oxygen contamination, providing a consistent interpretation of several recent experiments. We predict that other passivants that distort the tetrahedral bonding network at the surface, including other double-bonded groups and in some cases bridged oxygen, will also significantly affect the optical gap. Conversely, single-bonded passivants will have a minimal influence on the optical gap. A discussion of the difference in the strength of the optical transitions for clusters with different passivants is presented.
Gas temperature gradients in a CF4 inductive discharge
Authors: Abada Hana , Chabert Pascal , Booth Jean Paul , Robiche Jérôme , Cartry G.
Published: October 2002

The neutral gas temperature in a CF4 planar inductive discharge was measured with space and time resolution using laser-induced fluorescence of the CF radical with analysis of the rotationally resolved excitation spectra. Strong temperature gradients are observed and temperatures as high as 900 K are reached at the reactor center at 50 mTorr with a power density of 0.15 W/cm3. The temperature at the reactor center increases with both gas pressure and power, but is independent of the gas flow rate. A simple model based on the global thermal energy balance is proposed to explain these results. The fraction of the injected rf power consumed in gas heating varies from 4.4% to 42% under our conditions (5–50 mTorr, 250 W rf power). Axial temperature profiles were measured in the steady state and in the time afterglow. The typical temperature relaxation times are several hundreds of microseconds. A numerical two-dimensional, time-dependent thermal model is in good agreement with the results.
Photoelectron transport in CsI and CsBr coating films of alkali antimonide and CsI photocathodes
Authors: Shefer E. , Breskin A. , Boutboul T. , Chechik R. , Singh B. K. , Cohen H. , Feldman I.
Published: October 2002

The transport of low-energy (<3 eV) photoelectrons in CsI and CsBr films was investigated by direct photoionization in the film and by photoinjection of electrons from underlying K–Cs–Sb, Cs3Sb, and CsI photocathodes. Photoelectron energy distributions and the photoyield dependence on film thickness were studied, assisted by in situ x-ray photoelectron spectroscopy surface characterizations. A model describing electron transport through the coating film was used, which correlated well with experimental results from the various material combinations, coating thickness, and photon energies. The model provides valuable information on the interface potential barrier of theses systems, as well as quantum-yield attenuation length and photoelectron energy distributions.
Response to “Comment on ‘Conduction and low frequency channel noise of GaAs based pseudomorphic high electron mobility transistors’ ” [J. Appl. Phys. 91, 3318 (2002)]
Authors: Valenza M. , Vildeuil J. C. , Rigaud D.
Published: October 2002

This article gives several answers to the comments of Py and Buehlmann about our article “Conduction and low frequency channel noise of GaAs based pseudomorphic high electron mobility transistors” [J. Appl. Phys. 91, 3318 (2002)].
Size effect and fatigue mechanism in ferroelectric thin films
Authors: Jin H. Z. , Zhu Jing
Published: October 2002

Ferroelectric thin films such as barium strontium titanate (BST) and lead zirconate titanate (PZT) are potential materials for high-density dynamic/ferroelectric random-access memory applications. However, the properties of BST and PZT thin films are observed to be significantly inferior to their bulk counterparts. In addition, ferroelectric PZT films, when configured with metal electrodes, generally experience loss of switchable polarization (fatigue) under repetitive electrical cycling. We have reported previously that an interfacial defect layer was observed in BST/Pt interfaces. In this article, we discussed the possible origin of the interfacial defect layer and the effect it has on the thickness-dependent properties. We further suggested that fatigue in ferroelectrics could be explained by a field screening mechanism in which only a small fraction of the applied voltage is seen by the film bulk due to the screening effect of the interfacial layers.
Impact of localized states on the recombination dynamics in InGaN/GaN quantum well structures
Authors: Feng Shih-Wei , Cheng Yung-Chen , Chung Yi-Yin , Yang C. C. , Lin Yen-Sheng , Hsu Chen , Ma Kung-Jeng , Chyi Jen-Inn
Published: October 2002

Multiple-component decays of photoluminescence (PL) in InGaN/GaN quantum wells have been widely reported. However, their physical interpretations have not been well discussed yet. Based on wavelength-dependent and temperature-varying time-resolved PL measurements, the mechanism of carrier transport among different levels of localized states (spatially distributed) in such an indium aggregated structure was proposed for interpreting the early-stage fast decay, delayed slow rise, and extended slow decay of PL intensity. Three samples of the same quantum well geometry but different nominal indium contents, and hence different degrees of indium aggregation and carrier localization, were compared. The process of carrier transport was enhanced with a certain amount of thermal energy for overcoming potential barriers between spatially distributed potential minimums. In samples of higher indium contents, more complicated carrier localization potential structures led to enhanced carrier transport activities. Free exciton behaviors of the three samples at high temperatures are consistent with previously reported transmission electron microscopy results.
Microstructure and magnetic properties of Co/Pd multilayered thin films with C or Si seedlayer
Authors: Onoue T. , Asahi T. , Kuramochi K. , Kawaji J. , Osaka T. , Ariake J. , Ouchi K. , Sáfrán G. , Yaguchi N.
Published: October 2002

Microstructure and magnetic properties of sputter deposited Co/Pd multilayered perpendicular magnetization films with amorphous C or Si seedlayer were investigated. The angstrom scale surface roughness of the seedlayer causes fine crystal grains to form in the Co/Pd multilayer and to decrease the extent of intergranular exchange coupling, while it obstructs the formation of a regular interface between Co and Pd layers. The Si seedlayer, which exhibits a surface roughness lower than the C seedlayer, yields Co/Pd multilayered films with the lowest intergranular exchange coupling and the highest coercivity. The improvement in magnetic properties of the Co/Pd film with Si seedlayer is attributable mainly to the formation of Pd2Si at the interface between the Co/Pd layer and the Si seedlayer. The Pd2Si provides suitable nucleation sites for the grain growth of Co/Pd multilayered film that can be utilized as a perpendicular magnetic recording medium.
Electrostatic free energy calculations using the generalized solvent boundary potential method
Authors: Banavali Nilesh K. , Im Wonpil , Roux Benoı̂t
Published: October 2002

Free energy perturbation (FEP) calculations using all-atom molecular dynamics simulations with a large number of explicit solvent molecules are a powerful approach to study ligand–macromolecule association processes at the atomic level. One strategy to carry out FEP calculations efficiently and reduce computational time is to consider the explicit dynamics of only a small number of atoms in a localized region around the ligand. Such an approximation is motivated by the observation that the factors governing binding specificity are dominated by interactions in the vicinity of the ligand. However, a straightforward truncation of the system may yield inaccurate results as the influence exerted by the remote regions of the macromolecule and the surrounding solvent through long-range electrostatic effects may be significant. To obtain meaningful results, it is important to incorporate the influence of the remote regions of the ligand–macromolecule complex implicitly using some effective potential. The generalized solvent boundary potential (GSBP) that was developed recently [W. Im, S. Bernèche, and B. Roux, J. Chem. Phys. 114, 2924 (2001)] is an efficient computational method to represent the long-range electrostatic interactions arising from remote (outer) regions in simulations of a localized (inner) region with a small number of explicit atoms. In the present work, FEP calculations combined with GSBP are used to illustrate the importance of these long-range electrostatic factors in estimation of the charging free energy of an aspartate ligand bound to the aspartyl-tRNA synthetase. Calculations with explicit spherical simulation inner regions of different radii are used to test the accuracy of the GSBP method and also illustrate the importance of explicit protein and solvent dynamics in the free energy estimation. The influence of the represented outer region is tested using separate simulations in which the reaction field and/or the protein static field are excluded. Both components are shown to be essential to obtain quantitatively meaningful results. The ability of implicitly treating the influence of protein fluctuations in the outer region using a protein dielectric constant is examined. It is shown that accurate charging free energy calculations can be performed for this system with a spherical region of 15 to 20 Å radius, which roughly corresponds to 1500–3500 moving atoms. The results indicate that GSBP in combination with FEP calculations is a precise and efficient approach to include long-range electrostatic effects in the study of ligand binding to large macromolecules.
High-resolution infrared spectra of the C-H asymmetric stretch vibration of jet-cooled methoxy radical (CH3O)
Authors: Han Jia-xiang , Utkin Yu. G. , Chen Hong-bing , Burns L. A. , Curl R. F.
Published: October 2002

The high-resolution infrared spectrum of jet-cooled methoxy radical (CH3O) in the region 2850–2940 cm−1 has been recorded at about 26 K in a pulsed slit-jet expansion producing the radical by excimer laser flash photolysis. A perpendicular band centered near 2885 cm−1 was assigned to a portion of the C-H asymmetric stretch vibration (ν4) of CH3O by means of ground-state combination differences. Five ΔP=+1 subbands with P″=−1.5, −0.5, 0.5, 1.5, 2.5, and J″ up to 9.5 have been assigned. Because of the low jet temperature, the assigned transitions all arise from the ground E3/2 fine-structure component of the lowest vibronic state. Preliminary analysis yields values of A, B, and D of 5.232(12), 0.913(8), and 2.5(1.5)×10−5 cm−1, respectively. A small hyperfine splitting was observed in the P″=0.5 series transitions.
The structures of small gold cluster anions as determined by a combination of ion mobility measurements and density functional calculations
Authors: Furche Filipp , Ahlrichs Reinhart , Weis Patrick , Jacob Christoph , Gilb Stefan , Bierweiler Thomas , Kappes Manfred M.
Published: October 2002

A combined experimental and theoretical study of small gold cluster anions is performed. The experimental effort consists of ion mobility measurements that lead to the assignment of the collision cross sections for the different cluster sizes at room temperature. The theoretical study is based on ab initio molecular dynamics calculations with the goal to find energetically favorable candidate structures. By comparison of the theoretical results with the measured collision cross sections as well as vertical detachment energies (VDEs) from the literature, we assign structures for the small Aun− ions (n<13) and locate the transition from planar to three-dimensional structures. While a unique assignment based on the observed VDEs alone is generally not possible, the collision cross sections provide a direct and rather sensitive measure of the cluster structure. In contrast to what was expected from other metal clusters and previous theoretical studies, the structural transition occurs at an unusually large cluster size of twelve atoms.
Angular distributions and dichroism of photoelectrons ejected from fixed-in-space molecules of definite symmetry: Application to the C2v symmetry group
Authors: Kuznetsov V. V. , Cherepkov N. A. , Fecher G. H. , Schönhense G.
Published: October 2002

A theoretical investigation of the angular distributions of photoelectrons (ADP) ejected from fixed-in-space molecules or clusters having C2v symmetry is presented. The consideration is based on an expansion of the photoelectron wave functions in symmetry-adapted spherical harmonics. The ADP is derived for linearly polarized, circularly polarized, and unpolarized light in the case when the light beam is parallel to the C2 axis of the molecule. The twofold symmetry of the target reveals itself most clearly for circularly polarized or unpolarized light if the dependence on the azimuthal angle is studied for a fixed polar angle. The circular dichroism in the angular distribution (CDAD) is investigated for the general case of an arbitrary direction of the photon beam. It is shown on model examples that the CDAD has characteristic zeros in the mirror planes of the molecule that may be used to determine the symmetry of the initial state. For linearly polarized light the photoelectron angular distributions have a more complicated dependence on the azimuthal angle, though it also may be used to distinguish between different initial states. The examples presented in this paper demonstrate the general properties of the angular distributions as well as properties of the circular and linear dichroism in the angular distribution.
Molecular simulation study of the c(4×2) superlattice structure of alkanethiol self-assembled monolayers on Au(111)
Authors: Zhang Luzheng , Goddard William A. , Jiang Shaoyi
Published: October 2002

We report a molecular simulation study of the c(4×2) superlattice structure of alkanethiols on Au(111) based on an accurate force field developed from ab initio quantum chemical calculations. Quantum chemical calculations were performed on both clusters and periodic systems of methylthiols on Au(111) surfaces. Molecular mechanics and dynamics simulations of alkanethiols with various chain lengths on Au(111) were carried out. The c(4×2) superlattice structure was predicted for various chain lengths at a wide range of temperatures using the developed all-atom force field. Simulation results further show that tilt angle decreases as temperature increases, whereas monolayer thickness increases. The accurate force field developed is useful to molecular simulation studies of various systems involving self-assembled monolayers of alkanethiols on gold surfaces.
Switching the magnetic configuration of a spin valve by current-induced domain wall motion
Authors: Grollier J. , Lacour D. , Cros V. , Hamzic A. , Vaurès A. , Fert A. , Adam D. , Faini G.
Published: October 2002

We present experimental results on the displacement of a domain wall by injection of a dc current through the wall. The samples are 1-μm-wide long stripes of a CoO/Co/Cu/NiFe classical spin-valve structure. The stripes have been patterned by electron-beam lithography. A neck has been defined at 1/3 of the total length of the stripe and is pinning center for the domain walls, as shown by the steps of the giant magnetoresistance curves at intermediate levels (1/3 or 2/3) between the resistances corresponding to the parallel and antiparallel configurations. We show by electric transport measurements that, once a wall is trapped, it can be moved by injecting a dc current higher than a threshold current of the order of magnitude of 107 A/cm2. We discuss the different possible origins of this effect, i.e., local magnetic field created by the current and/or spin transfer from spin-polarized current.
Metal and composite nanocluster precipitate formation in silicon dioxide implanted with Sb+ ions
Authors: Ignatova V. A. , Lebedev O. I. , Wätjen U. , Van Vaeck L. , Van Landuyt J. , Gijbels R. , Adams F.
Published: October 2002

Amorphous thin SiO2 layers of different thickness on a Si(111) substrate were implanted with 12 keV 121Sb+ ions at fluences between 1×1015 cm−2 and 5×1015 cm−2, followed by thermal annealing. Formation of nanocrystal precipitates was established by high-resolution electron microscopy. The size and the distribution of the nanocrystals formed around the initial depth of implantation were studied in the as-implanted samples. The crystalline structure of these nanocrystals was also explored and the presence of antimony oxide Sb2O3 in the form of valentinite was proven. After the annealing step, the implanted material was observed to spread into a wider band and even to split into two discrete bands. The presence of antimony oxide in the intermediate phase (as-implanted layer of Sb) was confirmed using Fourier transform laser microprobe mass spectrometry. No definite signals of Sb2O3 could be detected in the annealed samples.
Angular dependence of the switching field of thin-film longitudinal and perpendicular magnetic recording media
Authors: Coffey Kevin R. , Thomson Thomas , Thiele Jan-Ulrich
Published: October 2002

An experimental survey of the angular dependence of the remanent switching fields for longitudinal and perpendicular magnetic recording media is presented and compared to the Stoner–Wohlfarth and Kondorsky models of magnetic switching. An experimental procedure is used where the remanence measured in the easy-axis direction is used to define the switching field for all angles of the applied field. Clear differences between different types of media are found. CoPtCrB alloy longitudinal recording media are found primarily to have a Stoner–Wohlfarth switching character. In contrast, the switching of perpendicular Co/Pd multilayer media is a mixture of Stoner–Wohlfarth rotation and domain-wall motion.
Mechanism of carrier transport in aluminum-doped zinc oxide
Authors: Tahar Radhouane Bel Hadj , Tahar Noureddine Bel Hadj
Published: October 2002

The conduction mechanism in aluminum-doped zinc oxide has been studied. Structural investigation shows that crystallographic orientation as well as grain boundary scattering can be neglected. Based on the analysis of the Hall mobility, it has been found that scattering at neutral and ionized impurities dominates the mobility. Further improvement in the mobility can be achieved by lowering the density of neutral impurities through careful control of the film processing parameters.
High-efficiency optical phase conjugation by degenerate four-wave mixing in volume media of disperse red 1-doped poly(methyl methacrylate)
Authors: Bian Shaoping , Zhang Weiya , Kim Sun Il , Embaye Natnael B. , Hanna Gabriel J. , Park Jeong Joon , Canfield Brian K. , Kuzyk Mark G.
Published: October 2002

High-efficiency optical phase conjugation (PC) by degenerate four-wave mixing in stress-processed volume media of disperse red 1 (DR1)-doped poly(methyl methacrylate) in the transparent region (647 nm) is reported. With vertically polarized counterpropagating pump waves, PC reflectivities of 43% and 37% were achieved, respectively, for a horizontally and vertically polarized probe wave, which is 50 times higher than the value reported on resonance. Reflectivities over 30% were achieved over a wide range of intensity for both polarization configurations. Photoinduced reorientation of the DR1 chromophore through trans-cis-trans isomerization is the dominant mechanism for the PC wave generation. Other mechanisms involved in the configuration of all vertical polarization waves are also examined. The roles of the polymer matrix and azo-dye photoisomerization in this high-efficiency PC process are also discussed.
Laser removal of paraffin wax from glass surfaces
Authors: Hirschausen D. , Kane D. M.
Published: October 2002

Waxes and thermopolymers are commonly used to mount optical and photonic materials prior to polishing and singularization. After demounting, residual wax/thermopolymer can adhere to the component surface, frequently in the form of particles. Dry, ultraviolet-pulsed laser cleaning has been demonstrated to effectively remove paraffin wax particles, prepared on a glass surface using a wax aerosol technique. This method produces dome-shaped particles. Experimental evidence suggests the dome-shaped particles are vaporized by the absorption of the energy from the laser pulse. A theoretical model based on vaporization has been developed and this leads to predictions of the critical fluence for single laser pulse removal of dome-shaped particles which is in good agreement with that experimentally measured (220 mJ/cm2). The model also gives insight into the geometries and relative thermal properties of the “particles” and surface, which are important in determining whether removal by vaporization is a viable process.
Optimization of Sm3+ fluorescence in Sm-doped yttrium aluminum garnet: Application to pressure calibration in diamond-anvil cell at high temperature
Authors: Sanchez-Valle Carmen , Daniel Isabelle , Reynard Bruno , Abraham Robert , Goutaudier Christelle
Published: October 2002

Sm 3+ concentration in Sm-doped yttrium aluminum garnet (Sm3+:YAG) has been optimized for fluorescence yield and synthesis procedure for the production of strain-free small grain-size powder established. Concentration of 0.5 wt % Sm3+ displays an optimal fluorescence signal, three to five times stronger than the generally proposed concentration (4 wt %). The fluorescence of the samples has been studied as a function of temperature (300–873 K) and pressure (0–15 GPa). A comparison with standard pressure scales shows that the pressure evolution of Sm3+:YAG fluorescence is insensitive to the doping rate, and that temperature has only a limited effect on the pressure scale established at 300 K. The present results indicate that pressure can be determined from the Y1 line of 0.5 wt % Sm-doped YAG, with temperature correction for ϖ at room pressure and constant pressure shift, within the 300–873 K and 10−4−15 GPa pressure-temperature range, through the linear relation: P (GPa)=0.127×[(ϖ0−0.018×ΔT)−ϖ] where ϖ0 corresponds to the Y1 frequency value at ambient conditions (16 185 cm−1).
Giant microcavity enhancement of second-harmonic generation in all-silicon photonic crystals
Authors: Dolgova T. V. , Maidykovski A. I. , Martemyanov M. G. , Fedyanin A. A. , Aktsipetrov O. A. , Marowsky G. , Yakovlev V. A. , Mattei G.
Published: October 2002

Second-harmonic generation (SHG) spectra of single and coupled porous silicon-based photonic crystal microcavities are studied in both frequency and wave vector domains. For the fundamental field resonant to the microcavity mode the second-harmonic intensity is enhanced by 102 times in comparison with that outside the photonic band gap. SHG spectroscopy in identical microcavities coupled through the intermediate Bragg reflector reveals two SHG peaks if the fundamental field is in resonance with the splitted mode of coupled microcavities. The spatial confinement of the resonant fundamental radiation is directly probed at the microcavity cleavage by scanning near-field optical microscopy.
Phase transformations of the decomposition type in systems with orbital degeneracy
Authors: Ivanov M. A. , Tkachev N. K. , Fishman A. Ya.
Published: October 2002

The immiscibility phase diagrams of systems exhibiting the cooperative Jahn–Teller effect are investigated. It is found that the Jahn–Teller mechanism of interaction between ions is capable of describing the main topologically different types of immiscibility phase diagrams in quasibinary systems.
On the origin of the blueshift from type-II quantum dots emission using microphotoluminescence
Authors: Nakaema M. K. K. , Iikawa F. , Brasil M. J. S. P. , Ribeiro E. , Medeiros-Ribeiro G. , Carvalho W. , Maialle M. Z. , Degani M. H.
Published: October 2002

We have studied type-II InP/GaAs self-assembled quantum dots by microphotoluminescence spectroscopy. Sharp spectral features were observed on top of a broad emission band. They are associated to statistical fluctuations from the ensemble of dots. Photoluminescence measurements as a function of the excitation intensity revealed markedly distinct behaviors: the broadband contour shows a large blueshift while the energy positions of the sharp features remain basically constant. We show that the large blueshift of the broad emission band in type-II quantum dots is not due to the barrier interface potential variation, but to the state filling of higher-energy states.
Tax-based Mechanisms in Urban Regeneration: Dublin and Chicago Models
Authors: McGreal Stanley , Berry Jim , Lloyd Greg , McCarthy John
Published: October 2002

The increasing interest in the potential use of fiscal incentives as a mechanism for stimulating urban renewal has been highlighted by a number of influential policy sources. This paper assesses the application and outcomes of tax-based incentives in urban regeneration, with particular focus upon the differing models represented by Dublin (Ireland) and Chicago (USA). Issues considered include utilisation of tax incentives, drawing-down of benefits, role of actor groups, ability to lever private-sector finance, impact on property market performance and wider economic influences. Conclusions advance the case for tax-based mechanisms as an instrument in the delivery of urban regeneration but stress the need for complementary structures to exploit fully the fiscal incentives.
Comparative Metabolism and Toxicokinetics of 14C-ResorcinoI Bis-Diphenylphosphate (RDP) in the Rat, Mouse, and Monkey
Authors: Freudenthal Ralph I. , McDonald Lee J. , Johnson Jodie V. , McCormick David L. , Henrich Richard T.
Published: October 2002

As part of a comprehensive program to examine the safety and toxicokinetics of the flame retardant, resorcinol bis-diphenylphosphate (RDP), the metabolism and toxicokinetics of RDP was determined after exposure of rats and monkeys to 14C-RDP via intravenous, inhalation, oral, or dermal routes. The metabolism of RDP was also determined in mice. Blood, urine, and fecal samples were collected at specified times for the quantification of 14C levels. Expired air was collected from rats. Excreta samples were quantitatively extracted. Chromatographic profiles of urinary and fecal metabolites were generated for multiple animals from each group. The major metabolites were isolated and then purified by a multistep chromatographic process. Structures of urinary and fecal metabolites were determined by HPLC-mass spectrometry (MS), MS-MS, and MS-MS-MS techniques. The metabolic pattern in all three species is complex. In certain urine and feces samples, radioactivity was associated with more than 30 HPLC peaks. There was little interanimal variability in metabolic profiles. No differences between species or sexes were apparent. The parent molecule, RDP, was present in significant amounts only in the feces of animals exposed by inhalation or gavage; this appears to reflect unabsorbed ingested material. Structures of all major urinary and fecal metabolites (representing 5% of the administered dose) in rats and primates were identified. The major fecal metabolites were resorcinol diphenylphosphate (RDP half ester), hydroxy-RDP half ester, dihydroxy-RDP, and hydroxy-RDP. Major urinary metabolites were identified as resorcinol, resorcinyl glucuronide, and resorcinyl sulfate. A small amount of 14CO2 was expired. This study confirms that RDP is metabolized in an identical manner by rats, mice, and primates, and that the rat and mouse are appropriate surrogates (animal models) in which to assess the toxicity of RDP. In both rats and primates, the highest peak plasma concentration (Cmax) and greatest area under the curve (AUC) was obtained with intravenous (TV) administration. In rats the Cmax for inhalation, oral, and dermal exposures were 42%, 10%, and 1%, respectfully. The AUC values for these three routes were 60%, 58%, and 15% of the IV AUC. Approximately 20% of the dermal dose was absorbed in the rat whereas primates absorbed only 10% of the applied dermal dose. Tissue accumulation and retention of radioactivity was minimal, indicating complete clearance of the administered dose.
Effect of Melatonin on Phase I and II Biotransformation Enzymes in Streptozotocin-Induced Diabetic Rats
Authors: Maritim Alice C. , Moore Brian H. , Sanders Ruth A. , Watkins John B.
Published: October 2002

Melatonin, a pineal secretory product known to be a scavenger of oxygen radicals, is widely used as a dietary supplement, although its toxicity has not been well characterized. Melatonin was administered (10 mg/kg IP in gum tragacanth, once a day for 4 successive days) to normal and 30-day streptozotocin-induced diabetic male Sprague-Dawley rats, after which activities of phase I and phase II biotransformation enzymes were assessed in the liver, kidney, intestine, and spleen. Most melatonin-induced effects were seen in the liver, and a few in extrahepatic tissues. In the liver, the effects of diabetes were reversed in two instances: hydroxylation of benzo[a]pyrene and glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene. In contrast to its effect on the phase I enzymes studied, whose activities were inhibited or unaffected by melatonin treatment, this treatment led to increased activity of glucuronyl transferase toward 4-methylumbelliferone in intestine of diabetic rats and toward 4-hydroxybiphenylin liver of normal rats. Hepatic glutathione S-transferaseactivity was also induced in normal rats after melatonin treatment, though the diabetic induction of this enzyme activity was reversed by melatonin. These results suggest that in addition to being a radical scavenger, melatonin, after 4 days of administration, does not induce the phase I enzymes studied, but may induce some hepatic phase II enzymes in normal but not diabetic rats.
The pharmacology of psilocybin
Authors: Passie Torsten , Seifert Juergen , Schneider Udo , Emrich Hinderk M.
Published: October 2002

Psilocybin (4‐phosphoryloxy‐N,N‐dimethyltryptamine) is the major psychoactive alkaloid of some species of mushrooms distributed worldwide.These mushrooms represent a growing problem regarding hallucinogenic drug abuse. Despite its experimental medical use in the 1960s, only very few pharmacological data about psilocybin were known until recently. Because of its still growing capacity for abuse and the widely dispersed data this review presents all the available pharmacological data about psilocybin.
Ethyl glucuronide: on the time course of excretion in urine during detoxification
Authors: Wurst Friedrich Martin , Seidl Stephan , Ladewig Dieter , Müller‐Spahn Franz , Alt Andreas
Published: October 2002

Ethyl glucuronide (EtG) is a promising new biological state marker of recent alcohol consumption that detects alcohol use reliably over a definite time period. Other currently available markers lack acceptable sensitivity and specificity. Our aim is to elucidate under naturalistic conditions the time course of EtG excretion in urine following alcohol consumption and to show how this can be utilized for monitoring and prognosis in patients. There are no other existing data on this issue to date. One hundred and thirty‐eight urine samples from 28 male alcohol withdrawal patients were drawn every 3‐24 hours for up to 94 hours after hospitalization. Breath ethanol concentration (mean) at hospitalization was 900 mg/L. Patient age in years was 40.3 (mean). Determination of urine EtG was performed by gas chromatography/mass spectrometry (GC/MS) with deuterium‐labelled EtG as an internal standard. The strongest correlations (p<0.01) were found between EtG determinations in the different patient when breath ethanol concentrations (BEC) were 0 and 48 hours after BEC=0 (r=0.747), EtG 24 and 48 hours after BEC=0 (r=0.872), and in the time frame of detection (hours) of EtG and EtG 48 hours after BEC=0 (r=0.762). No significant correlation was found (Mann‐Whitney test) between EtG concentrations in urine at different time points between the groups of patients with (a) 1 or less‐2, (b) 3‐4 or more previous hospitalizations, (c) a history of seizures (yes/no) or (d) an age above or below the median (40.5). EtG excretion in urine is not random, but seems rather to follow a kinetic profile. Furthermore our preliminary data indicate, that there is no significant difference for EtG concentration in urine when correlated to group variables such as age, seizures and hospitalizations.
Leiomyosarcoma of Bone Arising in Association with a Bone Infarct
Authors: Petra M. , Gibbons C. L. M. H. , Athanasou N. A.
Published: October 2002

Both primary leiomyosarcoma of bone and sarcoma arising in association with a bone infarct are rare events. In this case
report we describe for the first time a case of leiomyosarcoma arising in a bone infarct. The tumour arose in a medullary
infarct in the proximal femur of an elderly patient. As in other cases of sarcoma arising in a bone infarct, the prognosis was
poor, the patient dying within 6 months of diagnosis.