bluuebunny/crossref_metadata_2025 huggingface dataset:
Isomerisation of Erythro‐ and Threo‐Succinyl Units in Alternating Alkene‐Maleic Acid Copolymers: A Promising Route to New Microstructures
Authors: Komber Hartmut , Steinert Volker
Published: January 2005

Summary: A first route to the isomerisation of erythro‐ and threo‐2,3‐disubstituted succinyl units in alternating alkene‐maleic acid copolymers is presented. The isomerisation reactions of the disodium salt of ethene‐maleic acid copolymer were carried out in aqueous solution at 180–240 °C in an autoclave. It is demonstrated that the erythro‐content can be changed from 17% up to 67%. The dissociation of methine CH bonds with the intermediate formation of a sp2 hybridised carbon is proposed as the mechanism.

Isomerisation equilibrium between the threo‐ and erythro‐form of the 2,3‐disubstituted succinyl unit.

image

Isomerisation equilibrium between the threo‐ and erythro‐form of the 2,3‐disubstituted succinyl unit.
Cover Picture: Macromol. Rapid Commun. 2/2005
Authors: Hafrén Jonas , Córdova Armando
Published: January 2005

Cover: The first direct organocatalytic ring‐opening polymerization from cellulose fibers is presented. The synthesis was based on organocatalytic bulk ring‐opening polymerization (ROP) of ε‐caprolactone with cellulose cotton fiber and filter paper as the initiators. Organic acid catalysis provides a new method for the synthesis of valuable nanomaterials as well as polyesters for biomedical applications.

Further details can be found in the Communication by J. Hafrén* and A. Córdova* on page 82.
The role of ASTM E27 methods in hazard assessment part II: Flammability and ignitability
Authors: Britton Laurence G. , Cashdollar Kenneth L. , Fenlon William , Frurip David , Going John , Harrison B. Keith , Niemeier Jeff , Ural Erdem A.
Published: January 2005

Accurate flammability and ignitability data for chemicals form the cornerstone of procedures used to assess the hazards associated with commercial chemical production and use. Since 1967 the ASTM E27 Committee on the Hazard Potential of Chemicals has issued numerous, widely used consensus standards dealing with diverse testing and predictive procedures used to obtain relevant chemical hazard properties. The decision to issue a standard rests solely with the membership, which consists of representatives from industry, testing laboratories, consulting firms, government, academia, and instrument suppliers. Consequently, the procedures are automatically relevant, timely, and widely applicable. The purpose of this paper is to highlight some of the widely used standards, complemented with hypothetical but relevant examples describing the testing strategy, interpretation, and application of the results. A further goal of this paper is to encourage participation in the consensus standards development process.

The paper is published in two parts. The first part (in the preceding issue of Process Safety Progress) dealt with the E27 standards pertaining to thermodynamics, thermal stability, and chemical compatibility. The second part, published here, focuses on the flammability, ignitability, and explosibility of fuel and air mixtures. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005
High‐Tccuprate superconductivity in a nutshell
Authors: Won Hyekyung , Haas Stephan , Parker David , Maki Kazumi
Published: January 2005

Since the discovery of high‐Tccuprate superconductivity in 1986 many new experimental techniques and theoretical concepts have been developed. In particular it was shown that the BCS theory of d‐wave superconductivity describes semi‐quantitatively the high‐Tcsuperconductivity. Furthermore, it was demonstrated that Volovik's approach is extremely useful for finding the quasiparticle properties in the vortex state. Here we survey these developments and forecast future directions. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hubbard model in the ferromagnetic state. Dimer and trimer approach
Authors: Matlak M. , Słomska T. , Grabiec B.
Published: January 2005

We consider the Hubbard model for the sc lattice which consists of interacting, parallel lying dimer (trimer) planes. Each plane is a collection of equidistant, interacting, parallel lying dimers (trimers). We apply the exact solution of the dimer (trimer) problem after introducing the intrinsic symmetry breaking leading to the ferromagnetic ordering. We present preliminary, test results concerning the phase diagram of the system. In both approximations (dimer and trimer approach) there is a threshold for the ferromagnetic ordering at the Coulomb repulsion U = Ucr. The trimer approach gives a better saturation for the Curie temperature TC vs. U in comparison to the dimer approach. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mutagenic and antimutagenic potential of the medicinal plants M. laevigata and C. xanthocarpa
Authors: Fernandes J. B. F. , Vargas V. M. F.
Published: January 2005

Aqueous extracts of medicinal plants (Mikania laevigata and Campomanesia xanthocarpa) were screened for the presence of mutagenic activity in the Salmonella/microsome assay. The extracts of Campomanesia xanthocarpa showed frameshift (TA97a strain) signs of mutagenic activity without exogenous metabolism (S9 fraction). The infusions of Mikania laevigata, negative for mutagenic activity, showed high percentages of inhibition of mutagenesis induced by mutagens 2AF (2‐aminoﬂuorene), in the presence of exogenous metabolism (S9 fraction), for frameshift (TA98) and base pair substitution (TA100) lesions. In addition, these inhibitions were observed against mutagen SAZ (sodium azide) in assays with the TA100 strain, without exogenous metabolism (S9 fraction). A synergistic effect was also observed in frameshift mutagenic events, with direct action in the presence of 4NQO (4‐oxide‐1‐nitroquinoline) and a tendency to a low percentage of action enhancement, in the presence of the 2AF mutagen. The variable responses observed in the extract assays show the potentials for interaction of the different active principles in genetic material. Copyright © 2003 John Wiley & Sons, Ltd.
Antibacterial and antifungal activity of juniper berry oil and its selected components
Authors: Filipowicz Natalia , Kamiński Marcin , Kurlenda Julianna , Asztemborska Monika , Ochocka J. Renata
Published: January 2005

Juniper berry oil is stated to possess a wide spectrum of pharmacological activities and its monographs are included in some National Pharmacopoeias. The antibacterial and antifungal activity of the oil was reported by some authors. In our study we estimated the antibacterial and antifungal activity of three different juniper berry oils and their main components. All the micro‐organisms used in this experiment were isolated from patients of Regional Hospital of Gdańsk and some of them showed resistance against commonly used antibiotics. Only one of the oils (labelled A) revealed good antimicrobial properties. None of the single oil components was a stronger antibacterial and antifungal inhibitor than the oil A itself. Our data suggest that the antimicrobial activity of juniper oil A is the result of either the speciﬁc composition of the oil A (highest concentration of (−)‐α‐pinene, p‐cymene and β‐pinene) or activity of a single non‐identiﬁed compound. The presence of an adulterant in the oil was excluded. Copyright © 2003 John Wiley & Sons, Ltd.
The protective effect of Allium sativum L. clove aqueous and methanolic extracts against hypoxia‐induced lethality in mice
Authors: Hosseinzadeh Hossein , Sadati Nargess
Published: January 2005

The antihypoxic activity of Allium sativum clove (garlic) aqueous and methanolic extracts was studied in mice.

The extracts of garlic showed that the antihypoxic effect was dose‐dependent. The minimum effective doses of aqueous and methanolic extracts were 0.2 g/kg and 5.12 g/kg, respectively. Phenytoin, 50 mg/kg, and R‐phenylisopropyladenosine (R‐PIA), 1.6 mg/kg (R‐PIA) as positive controls increased survival time up to 52.5 ± 2.9 min and 120.5 ± 6 min, respectively, compared to normal saline (34.73 ± 0.71 min). The high doses of aqueous (16.9 g/kg) and methanolic (12.8 g/kg) extracts increased survival time up to 73.17 ± 4.9 and 68.41 ± 3.7, respectively.

These results indicated that the extracts of A. sativum cloves have a protective effect against hypoxia‐induced lethality in mice. Copyright © 2003 John Wiley & Sons, Ltd.
The activity against leukocyte eicosanoid generation of essential oil and polar fractions of Adesmia boronioides Hook.f.
Authors: González S. B. , Houghton P. J. , Hoult J. R. S.
Published: January 2005

The polar fractions (methanol and aqueous extract) and essential oil of Adesmia boronioides aerial parts were tested in vitro at concentrations of 15 and 50 µg/mL, for their effects on the COX and 5‐LOX pathways of eicosanoid generation (TXB2, PGE2 and LTB4) in stimulated rat peritoneal leukocytes. Potent inhibition of LTB4 generation was displayed by the methanol extract and the essential oil, whereas the aqueous extract was essentially inactive. The methanol extract also caused potent inhibition of TXB2 generation but the essential oil and the aqueous extract were much less active. The effects on PGE2 production were much less striking, implying that the main effect is on thromboxane synthetase rather than on COX. Although the essential oil caused LDH release in leukocytes treated concurrently with ionophore, suggesting substantial toxicity to the cells, this extract did not affect cell viability according to the MTT test when incubated with the cells in the absence of ionophore. The two other extracts did not affect cell viability at the concentrations tested. It is concluded that Adesmia boronioides contains substance(s) that preferentially inhibit the 5‐lipoxygenase activity of arachidonic acid metabolism and suggest that this may contribute to the antiinﬂammatory actions of extracts of this plant. Copyright © 2003 John Wiley & Sons, Ltd.
Essential amino acids interacting with flavonoids: A theoretical approach
Authors: Codorniu‐Hernández Edelsys , Mesa‐Ibirico Ariel , Hernández‐Santiesteban Richel , Montero‐Cabrera Luis A. , Martínez‐Luzardo Francisco , Santana‐Romero Jorge L. , Borrmann Tobias , Stohrer Wolf‐D.
Published: January 2005

The interaction of two flavonoid species (resorcinolic and fluoroglucinolic) with the 20 essential amino acids was studied by the multiple minima hypersurface (MMH) procedures, through the AM1 and PM3 semiempirical methods. Remarkable thermodynamic data related to the properties of the molecular association of these compounds were obtained, which will be of great utility for future investigations concerning the interaction of flavonoids with proteins. These results are compared with experimental and classical force field results reported in the available literature, and new evidences and criteria are shown. The hydrophilic amino acids demonstrated high affinity in the interaction with flavonoid molecules; the complexes with lysine are especially extremely stable. An affinity order for the interaction of both flavonoid species with the essential amino acids is suggested. Our theoretical results are compared with experimental evidence on flavonoid interactions with proteins of biomedical interest. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Wigner function of the rotating Morse oscillator
Authors: Stanek Jerzy , Konarski Jerzy
Published: January 2005

We present an analytical expression of the Wigner distribution function (WDF) for the bound eigenstates of the rotating Morse oscillator (RMO). The effect of rotational excitation on the WDF on the quantum phase space has been demonstrated. This effect has been visualized by a series of contour diagrams for given rovibrational quantum states. Rotations of the molecule have been proved to qualitatively and quantitatively change the Wigner function. As a result, the most probable distance between atoms in a rotating molecule changes, and depends on the parity of the vibrational quantum number. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Microcapillary liquid chromatography/tandem mass spectrometry using alkaline pH mobile phases and positive ion detection
Authors: Tomlinson Andy J. , Chicz Roman M.
Published: January 2005

Extending the dynamic range of microcapillary liquid chromatography/tandem mass spectrometry (LC/MS/MS) peptide sequencing methods is essential for extracting new discoveries from proteomic studies. The complexity of global protein digests and in vivo processed peptide repertoires (as isolated from immunologically important HLA complexes) have led to the development of novel separation methods to increase the number of peptides identified by a single analysis. Separation of complex mixtures by multidimensional high‐performance liquid chromatography (HPLC) decreases the number of isolated peptides contained in each fraction and increases the likelihood of detecting low abundant peptides in a background of dominant signals. In this study, we have evaluated the use of two dimensions of reversed‐phase chromatography for resolving and sequencing naturally processed HLA‐A2 presented peptide repertoires. The first dimension of separation was reversed‐phase chromatography using the strong ion pairing reagent trifluoroacetic acid (TFA) to ensure the highest efficiency of peptide fractionation. The second dimension of reversed‐phase chromatography was online with an electrospray ionization (ESI) ion trap mass spectrometer. Mobile phases used for the second dimension of chromatography were modified with volatile reagents including a contemporary acetate‐modified acidic solvent, which was compared with mobile phases prepared with ammonium hydroxide at an alkaline pH. As expected, we demonstrate improved separation of the HLA‐A2 presented fractions using the alkaline pH conditions. However, less obvious was the improved peptide signal‐to‐noise detected for peptide signals by positive ion ESI ion trap mass spectrometric detection, which was attributed to a reduced chemical background when using the alkaline pH mobile phases that allowed the ion trap to fill with the peptide ions until the automatic gain control detected a full trap. The term ‘wrong‐way‐round ionization’ has been used to describe intense [M+H]+ ions generated during ESI under strongly basic solutions. Ultimately, a larger number of the HLA‐A2 peptide repertoire was sequenced by coupling TFA‐modified reversed‐phase fractionation with alkaline‐modified microcapillary LC/MS/MS analysis of each fraction. In the present report, we compare the two second‐dimension approaches and demonstrate the quality of data that was acquired using alkaline pH reversed‐phase conditions. Copyright © 2003 John Wiley & Sons, Ltd.
Mass spectrometric study of aliphatic α‐carbonyl azides
Authors: Duarte M. Filomena , Martins Filipa , Fernandez M. Tereza , Langley G. John , Rodrigues Paula , Barros M. Teresa , Costa M. Lourdes
Published: January 2005

A series of derivatives of 2‐azidoacetic acid and 2‐azidoacetone were synthesized and their behaviour under electron ionization conditions was investigated. This paper reports the electron ionization fragmentation mechanisms for five aliphatic α‐carbonyl azides, which were clarified by accurate mass measurements and B/E linked scans. The substituent influences the abundance and the nature of the ions resulting from the molecular ion fragmentation. Copyright © 2003 John Wiley & Sons, Ltd.
Key issues in assessing the feasibility of reintroducing the great bustard Otis tarda to Britain
Authors: Osborne Patrick E.
Published: January 2005

The great bustard is a globally-threatened species needing conservation action across Europe. This paper discusses key issues in the case for reintroducing the bird to Britain. Great bustards became extinct as a breeding species in Britain in 1832 probably as a result of hunting, agricultural change and inclement weather. The factors that caused the loss are no longer thought to operate. Suitable habitat exists in pockets across England and especially on Salisbury Plain where a large area is protected for military training and conservation purposes. The Plain combines short grass areas for lekking, long grassland for feeding and adjacent arable land for nesting. Pilot studies on arthropods in long grassland suggest that their density is sufficient for chick-rearing but the precautionary creation of additional food-rich areas among arable crops is recommended. Genetic studies indicate that Britain's bustards probably belonged to the central European group and that restocking should not use birds from Iberia. Only Russia has sufficient birds to supply a reintroduction project and losses there through nest destruction are high. By rescuing eggs, artificially incubating them and transporting chicks to Britain, the project should have zero detriment to the donor population. Modelling indicates that 40 chicks will need to be brought to Britain for 5–10 years to build a founder population of 100 birds. Although focused on direct action in Britain, the project will promote grassland conservation across Europe and serve as a model for translocating bustards elsewhere.
Diet and habitat associations of bush dogs Speothos venaticus in the Interior Atlantic Forest of eastern Paraguay
Authors: Zuercher Gerald L. , Gipson Philip S. , Carrillo Osvaldo
Published: January 2005

The diet and habitat associations of bush dogs Speothos venaticus, categorized as Vulnerable on the IUCN Red List, are virtually unknown in the wild. In eastern Paraguay, bush dogs occur in the Reserva Natural del Bosque Mbaracayú. The Reserve contains one of the largest remaining fragments of the Interior Atlantic Forest in Paraguay as well as cerrado and grassland habitats. We analysed bush dog faeces to determine their diet. Bush dogs in the Reserve mostly ate vertebrates. Although small mammals (marsupials and rodents) were the most numerically dominant foods, agoutis Dasyprocta azarae and pacas Cuniculus paca represented 90.5% of biomass consumed. Cecropia fruit was also present in the diet. This is the first documentation of fruit consumption by bush dogs. Signs of bush dogs were detected in all habitats, with the greatest proportion in high forest.
Supervisory attentional control following carbon monoxide poisoning
Authors: JONES KERRY , KINSELLA GLYNDA JANE , ONG BEN , SCHEINKESTEL CARLOS
Published: January 2005

This study tested the hypothesis that carbon monoxide poisoning would
produce a deficit of attentional control, the supervisory attention
system, as indexed by attention switching and attentional scheduling,
and that routine attentional orienting would be unaffected.
Seventy-three cases of carbon monoxide poisoning were assessed at 3
days and 1 month post poisoning on tasks of attentional orienting, and
tasks of the supervisory attention system. The results were compared to
a group of 53 healthy community participants. A deficit of the
supervisory attentional system was documented on a task of attention
switching in survivors of both deliberate and accidental CO poisoning,
leaving attentional scheduling intact. There was no deficit of
attentional orienting in the current study. Alteration of consciousness
was found to predict subsequent supervisory attention system impairment
in correlation analyses, and the deficit was persistent for a 1 month
follow-up period. (JINS, 2004, 10, 843–850.)
Motor learning in children with spina bifida: Dissociation between
performance level and acquisition rate
Authors: EDELSTEIN KIM , DENNIS MAUREEN , COPELAND KIM , FREDERICK JON , FRANCIS DAVID , HETHERINGTON ROSS , BRANDT MICHAEL E. , FLETCHER JACK M.
Published: January 2005

The cerebellum is part of a neural circuit involved in procedural
motor learning. We examined how congenital cerebellar malformations
affect mirror drawing performance, a procedural learning task that
involves learning to trace the outline of a star while looking at the
reflection of the star in a mirror. Participants were 88 children with
spina bifida myelomeningocele, a neural tube defect that results in
lesions of the spinal cord, dysmorphology of the cerebellum, and
requires shunt treatment for hydrocephalus, and 35 typically developing
controls. Participants completed 10 trials in the morning and 10 trials
following a 3-hr delay. Although children with spina bifida
myelomeningocele were initially slower at tracing and made more errors
than controls, all participants improved their performance of the task,
as demonstrated by increased speed and accuracy across trials.
Moreover, degree of cerebellar dysmorphology was not correlated with
level of performance, rate of acquisition, or retention of mirror
drawing. The results suggest that congenital cerebellar dysmorphology
in spina bifida does not impair motor skill learning as measured by
acquisition and retention of the mirror drawing task. (JINS,
2004, 10, 877–887.)
Relation between subjective fogginess and neuropsychological
testing following concussion
Authors: IVERSON GRANT L. , GAETZ MICHAEL , LOVELL MARK R. , COLLINS MICHAEL W.
Published: January 2005

The purpose of this study was to examine the relation between the
subjective report of feeling foggy at one-week post concussion and
acute neuropsychological outcome. The outcome variables were derived
from a computerized neuropsychological screening battery, Immediate
Post-Concussion Assessment and Cognitive Testing (ImPACT). Participants
were 110 high school students who sustained a sports-related concussion
and were evaluated 5–10 days post injury (M = 6.8 days).
Athletes were divided into two groups on the basis of self-reported
fogginess. The first group reported no fogginess (n = 91),
whereas the second group reported experiencing some degree of fogginess
(n = 19) on a 6-point scale. The athletes with persistent
fogginess experienced a large number of other post-concussion symptoms,
compared to the athletes with no reported fogginess. In addition, the
athletes with persistent fogginess had significantly slower reaction
times, reduced memory performance, and slower processing speed. Thus,
athletes with any degree of self-reported fogginess at one-week post
injury are likely to have adverse effects from their concussions in
multiple domains. (JINS, 2004, 10, 904–906.)
Long-term neuropsychological outcomes of very low birth weight: Associations with early risks for periventricular brain insults
Authors: TAYLOR H. GERRY , MINICH NORI , BANGERT BARBARA , FILIPEK PAULINE A. , HACK MAUREEN
Published: January 2005

Few follow-up studies of children with very low birth weight (VLBW, <1,500 g) have examined neuropsychological sequelae at later ages or neonatal risks as predictors of these outcomes. The present study assessed cognitive skills at mean age 16 years in 48 participants with <750 g birth weight, 47 with 750–1,499 g birth weight, and 52 term-born controls. Our major objectives were to delineate the long-term cognitive consequences of VLBW, and to determine if risks for periventricular brain insults accounted for variations in outcomes. Analysis revealed poorer outcomes for the <750 g group than for term-born controls on nearly all measures, with specific impairments in visual–motor skills, spatial memory, and executive function. Predictors of outcome for participants with VLBW included lower birth weight, lower weight for gestational age, and a longer period of oxygen requirement for chronic lung disease. The longer-term consequences of VLBW are consistent with expectations based on early brain pathology and suggest limitations to functional plasticity. (JINS, 2004,10, 987–1004.)
Solar influence on the Indian Ocean Monsoon through dynamical processes
Authors: Kodera Kunihiko
Published: January 2005

The result of paleoclimate studies on the relationship between the Indian monsoon and solar activity, inferred from the analysis of stalagmites in Oman, is confirmed by using a modern meteorological dataset from 1958–1999. The present result suggests that the solar influence on monsoon activity is not due to a change in radiative heating in the troposphere but, rather, originates from the stratosphere through modulation of the upwelling in the equatorial troposphere, which produces a north‐south seesaw of convective activity over the Indian Ocean sector during summer. Higher precipitation over Arabia and India, thus, occurs during high solar activity.
Evolution of melt‐vapor surface tension in silicic volcanic systems: Experiments with hydrous melts
Authors: Mangan Margaret , Sisson Thomas
Published: January 2005

We evaluate the melt‐vapor surface tension (σ) of natural, water‐saturated dacite melt at 200 MPa, 950–1055°C, and 4.8–5.7 wt % H2O. We experimentally determine the critical supersaturation pressure for bubble nucleation as a function of dissolved water and then solve for σ at those conditions using classical nucleation theory. The solutions obtained give dacite melt‐vapor surface tensions that vary inversely with dissolved water from 0.042 (±0.003) J m−2 at 5.7 wt % H2O to 0.060 (±0.007) J m−2 at 5.2 wt % H2O to 0.073 (±0.003) J m−2 at 4.8 wt % H2O. Combining our dacite results with data from published hydrous haplogranite and high‐silica rhyolite experiments reveals that melt‐vapor surface tension also varies inversely with the concentration of mafic melt components (e.g., CaO, FeOtotal, MgO). We develop a thermodynamic context for these observations in which melt‐vapor surface tension is represented by a balance of work terms controlled by melt structure. Overall, our results suggest that cooling, crystallization, and vapor exsolution cause systematic changes in σ that should be considered in dynamic modeling of magmatic processes.
Earthquake statistics at Parkfield: 2. Probabilistic forecasting and testing
Authors: Schorlemmer D. , Wiemer S. , Wyss M. , Jackson D. D.
Published: January 2005

In paper 1 (Schorlemmer et al., 2004) we showed that the spatial b value (of the Gutenberg‐Richter relation) distribution at the Parkfield segment of the San Andreas fault remained stationary for the past 35 years. In this paper (paper 2) we extend those results, construct two probabilistic forecasts (H1 with a spatially varying b value and H2 with a uniform b value), and test these hypotheses against each other. Both hypotheses use a spatially varying seismicity level (a value) determined from past seismicity. We used a range of sampling parameters (magnitude threshold, cell size, etc.) to assure robust results. We found that in most of the tests, hypothesis H1 showed a higher likelihood than H2, although both are a poor approximation to the seismicity data. The most positive results for H1 are obtained for testing magnitude ranges down to M = 1.5 and with sampling radii as defined in paper 1 as appropriate for Parkfield. The superior performance of H1 suggests that spatially varying b values should be considered in earthquake forecasts.
Upper mantle structure in the south central Chilean subduction zone (30° to 36°S)
Authors: Wagner L. S. , Beck S. , Zandt G.
Published: January 2005

Regional P and S wave travel time data were used to obtain three‐dimensional seismic tomography models for Vp, Vs, and Vp/Vs above the subducting slab in central Chile and Argentina. In this region, there is an abrupt change from a normal subduction geometry south of 33°S to a flat subduction geometry to the north. We find low Vp, low Vs, and high Vp/Vs ratios in the southern half of our study area directly beneath the modern active volcanic arc, which we interpret as localized pockets of melt. In the northern half of our study area, above where the subducting Nazca plate flattens at 100 km depth, we find low Vp, high Vs, and low Vp/Vs ratios. These unusual results point to a lack of melt or hydrated mineralogies such as serpentine, both of which are characterized by high Vp/Vs values. The only mantle rocks that have low Vp/Vs and high Vs are Mg‐rich compositions, such as dehydrated serpentinite or orthopyroxenite. We suggest that significant portions of the mantle overlying the flat slab consist of orthopyroxenite, formed by a transient fluxing of silica‐rich fluids. Such fluids may have come from sediments that were subducted during the initiation of flat subduction at this latitude at ∼10 Ma. This would imply that the hydration of mantle material above a flat slab can be a transient phenomenon, which leaves little residual‐free water behind but significantly alters the mantle chemistry.
Fabrication and modeling of narrow capillaries for vacuum system gas inlets
Authors: Quaade Ulrich J. , Jensen Søren , Hansen Ole
Published: January 2005

Micrometer-sized cylindrical capillaries with well-controlled dimensions are fabricated using deep reactive ion etching. The flow through the capillaries is experimentally characterized for varying pressures, temperatures, and diameters. For the parameters used, it is shown that the Knudsen number is in the intermediate flow regime, and Knudsen’s expression for the flow fit the data well. The flow properties of the capillaries make them ideal for introducing gas into vacuum systems and in particular mass spectrometers.
Manganese-substituted cobalt ferrite magnetostrictive materials for magnetic stress sensor applications
Authors: Paulsen J. A. , Ring A. P. , Lo C. C. H. , Snyder J. E. , Jiles D. C.
Published: January 2005

Metal bonded cobalt ferrite composites have been shown to be promising candidate materials for use in magnetoelastic stress sensors, due to their large magnetostriction and high sensitivity of magnetization to stress. However previous results have shown that below 60°C the cobalt ferrite material exhibits substantial magnetomechanical hysteresis. In the current study, measurements indicate that substituting Mn for some of the Fe in the cobalt ferrite can lower the Curie temperature of the material while maintaining a suitable magnetostriction for stress sensing applications. These results demonstrate the possibility of optimizing the magnetomechanical hysteresis of cobalt ferrite-based composites for stress sensor applications, through control of the Curie temperature.
Secondary structures of short peptide chains in the gas phase:  Double resonance spectroscopy of protected dipeptides
Authors: Chin Wutharath , Dognon Jean-Pierre , Canuel Clélia , Piuzzi François , Dimicoli Iliana , Mons Michel , Compagnon Isabelle , von Helden Gert , Meijer Gerard
Published: January 2005

The conformational structure of short peptide chains in the gas phase is studied by laser spectroscopy of a series of protected dipeptides, Ac-Xxx-Phe-NH2, Xxx=Gly, Ala, and Val. The combination of laser desorption with supersonic expansion enables us to vaporize the peptide molecules and cool them internally; IR/UV double resonance spectroscopy in comparison to density functional theory calculations on Ac-Gly-Phe-NH2 permits us to identify and characterize the conformers populated in the supersonic expansion. Two main conformations, corresponding to secondary structures of proteins, are found to compete in the present experiments. One is composed of a doubly γ-fold corresponding to the 27 ribbon structure. Topologically, this motif is very close to a β-strand backbone conformation. The second conformation observed is the β-turn, responsible for the chain reversal in proteins. It is characterized by a relatively weak hydrogen bond linking remote NH and CO groups of the molecule and leading to a ten-membered ring. The present gas phase experiment illustrates the intrinsic folding properties of the peptide chain and the robustness of the β-turn structure, even in the absence of a solvent. The β-turn population is found to vary significantly with the residues within the sequence; the Ac-Val-Phe-NH2 peptide, with its two bulky side chains, exhibits the largest β-turn population. This suggests that the intrinsic stabilities of the 27 ribbon and the β-turn are very similar and that weakly polar interactions occurring between side chains can be a decisive factor capable of controlling the secondary structure.
Anomalous resisto-acoustic effect for leaky surface acoustic waves
Authors: Zaitsev B. D. , Kuznetsova I. E. , Teplykh A. A.
Published: January 2005

First the existence of anomalous resisto-acoustic effect for weakly inhomogeneous surface acoustic waves in structure “piezoelectric crystal—thin conducting film” was experimentally confirmed. At that the experimental value of the positive change in velocity turned out to be significantly less than the theoretically expected value for the ideal state of the crystal surface. The investigation showed that this effect is extremely sensitive to real state of the waveguide surface, which is caused by mechanical and chemical processing of sample, and also by technology of film deposition and removing. Taking into account the real state of the surface led to good agreement of theoretical results with experimental data.
Study of the noise of micromechanical oscillators under quality factor enhancement via driving force control
Authors: Tamayo Javier
Published: January 2005

The performance of devices based on micro- and nanomechanical oscillators depends critically on the quality factor (Q). The quality factor can be externally increased about two orders of magnitude by coherent amplification of the oscillation at resonance with a fast feedback amplifier. Here, theory and experiments performed with microcantilevers are presented to study the oscillation noise under external Q enhancement and how it differs from the noise when the Q is naturally enhanced by decreasing the mechanical energy loss. The application of the feedback amplifier produces a significant increase of the thermal noise and the noise that arises from the cantilever-displacement sensor. The main consequence is that the signal-to-noise ratio (S/N) remains constant and independent of the Q enhancement when measuring the amplitude and phase of the oscillation in the slope detection technique. This behavior is opposite to the enhancement of the S/N when the Q naturally increases, which is proportional to Q1∕2, ignoring instrumental sources of noise. More important, by taking into account the maximum driving force provided by the actuator, it is concluded that external Q enhancement does not enhance the sensitivity of devices based on micro- and nanomechanical oscillators, using the slope detection technique. The lack of sensitivity enhancement is attributed to the fact that thermal forces are not altered by the increase of the quality factor via the fast feedback amplifier. Finally, it is proposed to use the fast feedback amplifier in a different measurement mode to obtain high sensitivity. This consists in the self-excitation of the cantilever without application of a reference driving force, and the measurement of the frequency of the oscillation. Self-excitation of the cantilever produces amplification of the noise and its squeezing around the resonant frequency, hence the oscillation resembles Brownian motion of the cantilever with a superior quality factor.
Stark effect in the optical absorption in quantum wires
Authors: Lee Johnson , Spector Harold N.
Published: January 2005

We have calculated the effect of a transverse electric field on the ground and the first few excited states of the electrons confined in a quantum wire and used these results to examine the effect of the electric field on the intersubband optical absorption in such quantum wires. The electric field removes the degeneracies between several of the excited states in the wire, which leads to peaks in the intersubband optical absorption of the wire. The application of the electric field leads to a Stark shift of the electron energies, which is quadratic in the field at low fields but becomes almost linear in the field at high fields. The electric field shifts the peaks in a manner which depends upon the polarization of the optical field with respect to the applied electric field. We have also investigated the range of wire radii and electric fields at which the infinite well model is valid in a material where the height of the confining potential barrier is finite. We have found that for small wire radii and strong electric fields, the infinite well model breaks down.
Optimization techniques for the estimation of the thickness and the optical parameters of thin films using reflectance data
Authors: Ventura S. D. , Birgin E. G. , Martínez J. M. , Chambouleyron I.
Published: January 2005

The present work considers the problem of estimating the thickness and the optical constants (extinction coefficient and refractive index) of thin films from the spectrum of normal reflectance R. This is an ill-conditioned highly underdetermined inverse problem. The estimation is done in the spectral range where the film is not opaque. The idea behind the choice of this particular spectral range is to compare the film characteristics retrieved from transmittance T and from reflectance data. In the first part of the paper a compact formula for R is deduced. The approach to deconvolute the R data is to use well-known information on the dependence of the optical constants on photon energy of semiconductors and dielectrics and to formulate the estimation as a nonlinear optimization problem. Previous publications of the group on the subject provide the guidelines for designing the new procedures. The consistency of the approach is tested with computer-generated thin films and also with measured R and T spectral data of an a-Si:H film deposited onto glass. The algorithms can handle satisfactorily the problem of a poor photometric accuracy in reflectance data, as well as a partial linearity of the detector response. The results on gedanken films and on a-Si:H indicate a very good agreement between expected and retrieved values.
Ridge structure transformation by group-III species modification during the growth of (Al,Ga)As on patterned substrates
Authors: Williams R. S. , Ashwin M. J. , Jones T. S. , Neave J. H.
Published: January 2005

AlAs growth by molecular-beam epitaxy has been successfully achieved on ⟨100⟩-aligned mesas on GaAs (001) patterned substrates. The final ridge morphology was found to be radically different from that observed from the homoepitaxial growth of GaAs on similar substrates. The significant modification to the final ridge profile is related to the reduction of the adatom diffusion length when using Al as the group-III species. These results provide direct evidence of a growth mode modification with alteration of the group-III element from Ga to Al and have significant implications for controlling the ridge formation process and for fabrication of more complex structures.
Control of a fluid particle under simulated deep-ocean conditions in a high-pressure water tunnel
Authors: Haljasmaa Igor V. , Vipperman Jeffrey S. , Lynn Ronald J. , Warzinski Robert P.
Published: January 2005

An apparatus that permits the observation of liquid CO2 particles in a simulated deep-ocean environment was designed, modeled, constructed, and tested. Analysis concerning the vertical stability and control of the fluid particle in a countercurrent flow loop is presented. The vertical position of the particle was found to vary due to the gradual dissolution of the CO2 into the water and various other random effects. Using linearized equations for spherical particle motion in the fluid flow, a second-order dynamic equation is derived and analyzed. The servocontrol system consists of a video system that digitizes particle position in a viewing window and a centrifugal pump that can control the speed of the countercurrent flow in order to maintain the particle within the observation window of a charge-coupled device camera. Currently, the system is being used to obtain information on the dissolution behavior of CO2 in seawater at various conditions of pressure and temperature that simulate ocean depths down to 3400m. This information can be used to predict the fate of CO2 drops in the ocean, whether released from natural seeps, leaks from suboceanic geologic CO2 storage sites, or from engineered deep-ocean injection systems. The study of other liquids and gases is also possible.
Role of SDF1 chemokine in the development of lateral line efferent and facial motor neurons
Authors: Sapède Dora , Rossel Mireille , Dambly-Chaudière Christine , Ghysen Alain
Published: January 2005

Most sensory systems are innervated by efferent neurons as well as by afferent neurons. The efferent innervation modulates the sensitivity of the receptor cells or of the sensory terminals. In the posterior lateral line system of the zebrafish, two efferent nuclei have been described in the hindbrain. Here we examine the development of the efferent neurons. We show that their axons are guided toward the target organ along the lateral line nerve while their cell bodies migrate posteriorward across rhombomeres to achieve their final position in rhombomeres 6/7. This migration depends on the SDF1 chemokine. We show that the migration of motor neurons of the facial nucleus from rhombomere 4 to 6 is also affected in
sdf1a
morphants (embryos injected with morpholine-conjugated antisense oligonucleotides). We propose that SDF1/CXCR4-mediated cell migration is preferentially associated with movement along the anteroposterior axis of the animal.
Relationship between retroviral DNA-integration-site selection and host cell transcription
Authors: Maxfield Lori F. , Fraize Camilla D. , Coffin John M.
Published: January 2005

Retroviral DNA integration occurs throughout the genome; however, local “hot spots” exist where a strong preference for certain sites over others are seen, and more global preferences associated with genes have been reported. Previous data from our laboratory suggested that there are fewer integration events into a DNA template when it is undergoing active transcription than when it is not. Because these data were generated by using a stably transfected foreign gene that was only weakly inducible, we have extended this observation by comparing integration events into a highly inducible endogenous gene under both induced and uninduced transcriptional states. To examine the influence of transcription on site selection directly, we analyzed the frequency and distribution of integration of avian retrovirus DNA into the metallothionein gene, before and after its induction to a highly sustained level of expression by addition of ZnSO
4
. We found a 6-fold reduction in integration events after 100-fold induction of transcription. This result implies that, despite an apparent preference for integration of retroviral DNA into transcribed regions of host DNA, high-level transcription can be inhibitory to the integration process. Several possible models for our observation are as follows. First, when a DNA template is undergoing active transcription, integration might be blocked by the RNA polymerase II complex because of steric hindrance. Alternatively, the integrase complex may require DNA to be in a double-stranded conformation, which would not be the case during active transcription. Last, transcription might lead to remodeling of chromatin into a structure that is less favorable for integration.
Somatostatin receptor scintigraphy with 99mTc-depreotide (neospect) in discriminating between malignant and benign lesions in the diagnosis of lung cancer: a pilot study
Authors: Bååth M. , Kölbeck K. G. , Danielsson R.
Published: January 2005

Purpose: To evaluate the diagnostic value of a new somatostatin analog, 99mTc-Depreotide, in differentiating benign from malignant lesions in patients with pulmonary nodules or masses.

Material and Methods: A pilot study was performed on 28 patients referred to our Lung Department on suspicion of lung cancer. A chest X-ray, computed tomography (CT) of the thorax and upper abdomen, and scintigraphy were done - scintigraphy following the administration of 740 MBq 99mTc-Depreotide. Planar and tomographical imaging of the thorax and whole-body scanning with a gamma camera were done, and diagnostic outcome of the scintigrams was compared to CT, pathology, and clinical outcome.

Results: Of 21 patients who had a focal high uptake of Depreotide, 17 were malignancies. One patient had two lesions with high Depreotide uptake, lung cancer, and pneumonia in the contralateral lung. Two patients with sarcoidosis and one with bilateral round atelectasis also had high Depreotide uptake bilaterally. Seven of the 8 patients with no uptake were true negative: 5 hamartomas and 2 round atelectases. One small lung cancer in the pleura sinus did not have Depreotide uptake.

Conclusion: The somastotatin analog Depreotide is promising for discriminating between malignant and benign lung lesions.
Dynamic Recruitment of Nek2 Kinase to the Centrosome Involves Microtubules, PCM-1, and Localized Proteasomal Degradation
Authors: Hames Rebecca S. , Crookes Renarta E. , Straatman Kees R. , Merdes Andreas , Hayes Michelle J. , Faragher Alison J. , Fry Andrew M.
Published: January 2005

Centrosomes undergo dramatic changes in composition and activity during cell cycle progression. Yet mechanisms involved in recruiting centrosomal proteins are poorly understood. Nek2 is a cell cycle–regulated protein kinase required for regulation of centrosome structure at the G2/M transition. Here, we have addressed the processes involved in trafficking of Nek2 to the centrosome of human adult cells. We find that Nek2 exists in small, highly dynamic cytoplasmic particles that move to and from the centrosome. Many of these particles align along microtubules and a motif was identified in the Nek2 C-terminal noncatalytic domain that allows both microtubule binding and centrosome localization. FRAP experiments reveal that 70% of centrosomal Nek2 is rapidly turned over (t1/2∼ 3 s). Microtubules facilitate Nek2 trafficking to the centrosome but only over long distances. Cytoplasmic Nek2 particles colocalize in part with PCM-1 containing centriolar satellites and depletion of PCM-1 interferes with centrosomal recruitment of Nek2 and its substrate C-Nap1. Finally, we show that proteasomal degradation is necessary to allow rapid recruitment of new Nek2 molecules to the centrosome. Together, these data highlight multiple processes involved in regulating the abundance of Nek2 kinase at the centrosome including microtubule binding, the centriolar satellite component PCM-1, and localized protein degradation.
Yos1p Is a Novel Subunit of the Yip1p–Yif1p Complex and Is Required for Transport between the Endoplasmic Reticulum and the Golgi Complex
Authors: Heidtman Matthew , Chen Catherine Z. , Collins Ruth N. , Barlowe Charles
Published: January 2005

Yeast Yip1p is a member of a conserved family of transmembrane proteins that interact with Rab GTPases. Previous studies also have indicated a role for Yip1p in the biogenesis of endoplasmic reticulum (ER)-derived COPII transport vesicles. In this report, we describe the identification and characterization of the uncharacterized open reading frame YER074W-A as a novel multicopy suppressor of the thermosensitive yip1-4 strain. We have termed this gene Yip One Suppressor 1 (YOS1). Yos1p is essential for growth and for function of the secretory pathway; depletion or inactivation of Yos1p blocks transport between the ER and the Golgi complex. YOS1 encodes an integral membrane protein of 87 amino acids that is conserved in eukaryotes. Yos1p localizes to ER and Golgi membranes and is efficiently packaged into ER-derived COPII transport vesicles. Yos1p associates with Yip1p and Yif1p, indicating Yos1p is a novel subunit of the Yip1p–Yif1p complex.