bluuebunny/crossref_metadata_2025_split huggingface dataset:
Indirect detection of lung perfusion using susceptibility‐based hyperpolarized gas imaging
Authors: Dimitrov Ivan E. , Insko Erik , Rizi Rahim , Leigh John S. 
Published: January 2005

AbstractPurposeTo address the problem of inadequate signal‐to‐noise ratio (SNR) encountered in lung perfusion magnetic resonance imaging (MRI) by developing an indirect detection based on the strong hyperpolarized (HP) gas signal.Materials and MethodsOur model is based on detecting the effects of gadolinium (Gd) flowing through lung capillaries by recording the phase of the nearby alveolar HP gas. In a HP gas 3He phantom we imaged gas phases before and after removing tubes containing paramagnetic solution away from the phantom. We also imaged HP gas phases in pig lungs before and after injection of Gd. Finally, parenchymal spin phase in excised lungs was measured as a function of Gd concentration.ResultsIn the phantom, the differential phase map displayed a pattern characteristic of a susceptibility‐induced dipole field, showing the possibility of an indirect detection. In vivo, the differential phase map showed homogeneous appearance, as expected for uniform perfusion in healthy lungs. Ex vivo, the parenchymal spin phases were shown to depend linearly on Gd concentration.ConclusionOur method should allow indirect perfusion (Q) and direct ventilation (V) to be assessed simultaneously, thus allowing for diagnosis of V/Q mismatches. The linear dependency of parenchymal spin phase vs. Gd concentration may allow for quantification of lung perfusion. J. Magn. Reson. Imaging 2005;21:149–155. © 2005 Wiley‐Liss, Inc.
3.0‐Tesla MR angiography of intracranial aneurysms: Comparison of time‐of‐flight and contrast‐enhanced techniques
Authors: Gibbs Gordon F. , Huston John , Bernstein Matthew A. , Riederer Stephen J. , Brown Robert D. 
Published: January 2005

AbstractPurposeTo determine whether 3.0‐T elliptical‐centric contrast‐enhanced (CE) magnetic resonance (MR) angiography is superior to 3.0‐T elliptical‐centric time‐of‐flight (TOF) MR angiography in the detection and characterization of intracranial aneurysms, and to determine whether increasing the acquisition matrix size in 3.0‐T CE MR angiography improves image quality.Materials and MethodsA total of 50 consecutive patients referred for MR angiographic evaluation of a known or suspected intracranial aneurysm underwent MR angiography, including three‐dimensional TOF and elliptical‐centric CE techniques at 3.0 T. The 3.0‐T three‐dimensional TOF and 3.0‐T CE examinations were graded for image quality. A blind review identified the presence and location of aneurysms.ResultsA total of 28 aneurysms were identified in 23 of the 50 patients. The 3.0‐T TOF MR angiography had a higher mean score for image quality than the 3.0‐T elliptical‐centric CE MR angiography (P < 0.0001). A total of 14 patients with aneurysms had conventional angiography for comparison. The 3.0‐T TOF showed all the aneurysms, whereas 3.0‐T CE MR angiography did not show 1 of 19 aneurysms when conventional angiography was the reference standard.ConclusionFor imaging intracranial aneurysms, 3.0‐T TOF MR angiography offers better image quality than 3.0‐T CE MR angiography using the elliptical‐centric technique. J. Magn. Reson. Imaging 2005;21:97–102. © 2005 Wiley‐Liss, Inc.
Loss of synaptophysin‐positive boutons on lumbar motor neurons innervating the medial gastrocnemius muscle of the SOD1G93A G1H transgenic mouse model of ALS
Authors: Zang Da Wei , Lopes Elizabeth C. , Cheema Surindar S. 
Published: January 2005

AbstractAmyotrophic lateral sclerosis (ALS) is a common form of motor neuron disease (MND) that involves both upper and lower nervous systems. In the SOD1G93A G1H transgenic mouse, a widely used animal model of human ALS, a significant pathology is linked to the degeneration of lower motor neurons in the lumbar spinal cord and brainstem. In the current study, the number of presynaptic boutons immunoreactive for synaptophysin was estimated on retrogradely labeled soma and proximal dendrites of α and γ motor neurons innervating the medial gastrocnemius muscle. No changes were detected on both soma and proximal dendrites at postnatal day 60 (P60) of α and γ motor neurons. By P90 and P120, however, α motor neuron soma had a reduction of 14 and 33% and a dendritic reduction of 19 and 36%, respectively. By P90 and P120, γ motor neuron soma had a reduction of 17 and 41% and a dendritic reduction of 19 and 35%, respectively. This study shows that levels of afferent innervation significantly decreased on surviving α and γ motor neurons that innervate the medial gastrocnemius muscle. This finding suggests that the loss of motor neurons and the decrease of synaptophysin in the remaining motor neurons could lead to functional motor deficits, which may contribute significantly to the progression of ALS/MND. © 2005 Wiley‐Liss, Inc.
Dehydroascorbic acid prevents oxidative cell death through a glutathione pathway in primary astrocytes
Authors: Kim Eun Joo , Park Yong Gou , Baik Eun Joo , Jung Se Jung , Won Ran , Nahm Taik Sang , Lee Bae Hwan 
Published: January 2005

AbstractAscorbic acid (AA) is a well‐known antioxidant. It also has pro‐oxidant effects, however, in the presence of free transition metals. Because of the pro‐oxidant effects of AA, dehydroascorbic acid (DHA), an oxidized form of AA, has been used as a substitute for AA. DHA has been shown recently to have a protective effect in an experimental stroke model. This study was carried out to determine if DHA has different effects from AA on hydrogen peroxide (H2O2)‐induced oxidative cell death in primary astrocytes. DHA was found to prevent cell death and reverse mitochondrial dysfunction after exposure to H2O2. DHA significantly increased the glutathione peroxidase (GPx) and glutathione reductase (GR) activities 1 hr after H2O2 exposure. Moreover, DHA not only reversed the decrease in the glutathione (GSH) levels, but also significantly enhanced it by stimulating the pentose phosphate pathway (PPP) 15 hr after H2O2 exposure. DHA also reduced production of reactive oxygen species (ROS) after H2O2 exposure. In contrast, AA accelerated H2O2‐induced cell death. To determine if the pro‐oxidant effect of AA is related to iron, the effect of AA on cell death was examined using an iron chelator, desferrioxamine. Even though co‐pretreatment with AA and desferrioxamine could abrogate the aggravating effects of AA on H2O2‐induced cell death at early stages, it could not prevent H2O2‐induced cell death over a 24‐hr period. These results suggest that DHA has distinct effects from AA and prevent H2O2‐induced cell death by increasing the GSH levels mediated by the GPx and GR activities and PPP. © 2005 Wiley‐Liss, Inc.
Growth‐associated protein‐43 is degraded via the ubiquitin‐proteasome system
Authors: De Moliner K.L. , Wolfson M.L. , Perrone Bizzozero N. , Adamo A.M. 
Published: January 2005

AbstractGrowth‐associated protein‐43 (GAP‐43) is a phosphoprotein whose expression in neurons is related to the initial establishment and remodeling of neural connections. GAP‐43 gene expression is known to be regulated at both the transcriptional and the postranscriptional levels. However, very little is known about the cellular mechanism involved in the degradation of this protein. Ubiquitin (Ub) is well known for its role in targeting cytoplasmic proteins for degradation by the 26S proteasome. The ubiquitin‐proteasome system (UPS) consists of a conserved cascade of three enzymatic components that attach Ub covalently to various substrates and control the degradation of protein involved in several important cellular processes. In this study, we investigated the degradation of GAP‐43 in transfected NIH 3T3 cells and neuronal cultures. We found that the proteasome inhibitors, lactacystin and MG132 increased the cellular GAP‐43 level, leading to the accumulation of polyubiquitinated forms of this protein in transfected cells and that the Ub‐proteasome pathway is also involved in the turnover of this protein in neurons. We conclude based on our findings that GAP‐43 is a substrate of the UPS. © 2005 Wiley‐Liss, Inc.
An increase in intracellular free calcium ions by nicotinic acetylcholine receptors in a single cultured rat cortical astrocyte
Authors: Oikawa Hirotaka , Nakamichi Noritaka , Kambe Yuki , Ogura Masato , Yoneda Yukio 
Published: January 2005

AbstractNeuronal nicotinic acetylcholine receptors (nAChRs) are composed of an assembly between at least seven alpha (α2–α7, α9) and three beta (β2–β4) subunits in mammals. The addition of 50 mM KCl or 1 mM nicotine immediately increased the number of cells with high fluorescence intensity in rat cortical astrocytes on fluo‐3 fluorescence measurement. Nicotine was effective at increasing the fluorescence intensity in astrocytes cultured for 2 days after replating, but not in those used 1 or 5 days after replating, without markedly affecting the cellular viability irrespective of the exposure period. Nicotine markedly increased the fluorescence intensity in a concentration‐dependent manner at a concentration range of 10–100 μM in cultured astrocytes when analyzed on a responsive single cell. In these responsive single cells, the increase by nicotine was significantly prevented by the heteromeric α4/β2 subtype antagonist dihydro‐β‐erythroidine and the homomeric α7 subtype antagonist methyllycaconitine, as well as by nifedipine and EGTA but not thapsigargin. Methyllycaconitine failed to inhibit further the increase by nicotine in the presence of nifedipine, however, whereas the expression of mRNA was seen for all mammalian neuronal nAChR subunits in cultured rat cortical astrocytes as well as neurons. These results suggest that nicotine may increase intracellular free Ca2+ through the influx of extracellular Ca2+ across L‐type voltage‐gated Ca2+ channels rather than Ca2+ release from intracellular stores, in a manner related to the α4/β2 and/or α7 nAChR channels functionally expressed in cultured rat cortical astrocytes. © 2005 Wiley‐Liss, Inc.
Deglaciation of the Irish Sea Basin: a critique of the glaciomarine hypothesis
Authors: McCarroll Danny 
Published: January 2005

AbstractThe glaciomarine model for deglaciation of the Irish Sea basin suggests that the weight of ice at the last glacial maximum was sufficient to raise relative sea‐levels far above their present height, destabilising the ice margin and causing rapid deglaciation. Glacigenic deposits throughout the basin have been interpreted as glaciomarine. The six main lines of evidence on which the hypothesis rests (sedimentology, deformation structures, delta deposits, marine fauna, amino‐acid ratios and radiocarbon dates) are reviewed critically. The sedimentological interpretation of many sections has been challenged and it is argued that subglacial sediments are common rather than rare and that there is widespread evidence of glaciotectonism. Density‐driven deformation associated with waterlain sediments is rare and occurs where water was ponded locally. Sand and gravel deposits interpreted as Gilbert‐type deltas are similarly the result of local ponding or occur where glaciers from different source areas uncoupled. They do not record past sea‐levels and the ad hoc theory of ‘piano‐key tectonics’ is not required to explain the irregular pattern of altitudes. The cold‐water foraminifers interpreted as in situ are regarded as reworked from Irish Sea sediments that accumulated during much of the late Quaternary, when the basin was cold and shallow with reduced salinities. Amino‐acid age estimates used in support of the glaciomarine model are regarded as unreliable. Radiocarbon dates from distinctive foraminiferal assemblages in northeast Ireland show that glaciomarine sediments do occur above present sea‐level, but they are restricted to low altitudes in the north of the basin and record a rise rather than a fall in sea‐level. It is suggested here that the oldest dates, around 17 000 yr BP, record the first Late Devensian (Weichselian) marine inundation above present sea‐level. This accords with the pattern but not the detail of recent models of sea‐level change. Copyright © 2001 John Wiley & Sons, Ltd.
Subglacial bedform geomorphology of the Irish Ice Sheet reveals major configuration changes during growth and decay
Authors: Clark Chris D. , Meehan Robert T. 
Published: January 2005

AbstractThe belated realisation that ribbed (Rogen) moraines form such an integral part of Irish geomorphology, and the piecemeal approach to previous drumlin mapping, is probably responsible for the highly contrasting views of palaeoflow patterns of the Irish Ice Sheet. Using a high resolution (25 m) digital elevation model we present morphological maps of a large part (100 × 100 km) of the so‐called ‘Drumlin Belt’ of north central Ireland. The landforms comprise mostly ribbed moraine much larger than found elsewhere (up to 16 km in length), which in places are superimposed on each other. Contrary to most prior assessments we find the bedform record to contain numerous and overlapping episodes of bed formation (ribbed moraine, drumlins and crag‐and‐tails) that provide a palimpsest record of changing flow geometries. These demonstrate an ice sheet with a centre of mass and flow geometry that changed during growth and decay.Using distinctive flow patterns and relative age relationships between them we reconstruct ice sheet evolution into four phases during a single glacial cycle. In phase 1 (early in the glacial cycle), Scottish and local ice coalesced to form a northeast‐centred Irish Ice Sheet. As it grew its centre of mass migrated southwards, culminating in a major N–S divide positioned down the east of Ireland (phase 2, ca. Last Glacial Maximum). During retreat, the centre of mass migrated at least 120 km northwards and became established in northwest Ireland and at this point a dramatic bedforming event produced one of the world's largest and most contiguous ribbed moraine fields (phase 3). Final deglaciation is thought to be by fragmentation into many topographically controlled minor ice‐caps (phase 4). Rather than any dramatic or unexpected behaviour, the reconstructed phases indicate a relatively predictable pattern of ice sheet growth and decay with changes in centres of mass, and does not require major readvances or ice‐stream events. Copyright © 2001 John Wiley & Sons, Ltd.
Glaciomarine deposition around the Irish Sea basin: some problems and solutions
Authors: Knight Jasper 
Published: January 2005

AbstractReconstructing the depositional processes and setting (marine or terrestrial depositional environment) of late Devensian age glacigenic sediments around the Irish Sea basin (ISB) is critical for developing an all‐embracing and consistent glacial model that can account for all observed field evidence. Identifying episodes of marine and terrestrial glacial deposition from field data is considered the first step in achieving this goal. Criteria for distinguishing marine and terrestrial glacial environments in the ISB include the geomorphology, sedimentology and faunal content (biofacies) of the associated deposits.Exposures of glacigenic sediments around the ISB are very diverse in terms of their morphosedimentary characteristics and associated biofacies, and thus inferred depositional processes and setting. Possible reasons for the diverse geological record include the differing geometry of eastern and western ISB coasts, time‐transgressive ice retreat, and differential land rebound effects as a result of forebulge collapse and neotectonics. Poor geochronometric control on ice sheet events has not helped the correlation of ISB events with glacial and climatic events elsewhere. Future investigations of glacial sites around the ISB should use an integrated methodological approach involving a range of geomorphological, sedimentary and biofacies data, and dating control where possible. This will help in developing a more precise and holistic late Devensian glacial model that is constrained rigorously by field geological evidence. Copyright © 2001 John Wiley & Sons, Ltd.
Sea‐level change in the Irish Sea since the Last Glacial Maximum: constraints from isostatic modelling
Authors: Lambeck Kurt , Purcell Anthony P. 
Published: January 2005

AbstractModels of glacio‐hydroisostatic sea‐level change have been published for the British Isles that are broadly consistent with the observational evidence, as well as with glaciological constraints. It has been argued, however, that the models fail to represent sea‐level change along the Irish Sea margins and in southern Ireland for the post‐deglaciation period. The argument rests on the interpretation of the depositional environment of the elevated ‘Irish Sea Drift’ on both sides of the Irish Sea: whether this is terrestrial or glaciomarine. The isostatic models for the British Isles are consistent with the former interpretation in that sea‐levels on either side of the Irish Sea, south of about the Isle of Man, are not predicted to have risen above present sea‐level at any time since the deglaciation of the Irish Sea. This implies that ice over both the Irish Sea and Ireland was relatively thin (ca. 600–700 m over Ireland). If the glaciomarine interpretation of the elevated Irish Sea Drift is correct, then the maximum ice thickness over central and southern Ireland would have to reach 2000 m, exceeding that over Scotland. Furthermore, for the resulting sea‐level change to be consistent with the Holocene evidence, this thick ice sheet could not have extended to the eastern side of the Irish Sea. Nor could it have been very thick at its northern and western limits. If such an ice model is extreme and incompatible with glaciological observations then the alternative is to accept the interpretation of the Irish Sea Drift as terrestrial in origin. Copyright © 2001 John Wiley & Sons, Ltd.
Devensian glacigenic sedimentation and landscape evolution in the Cardigan area of southwest Wales
Authors: Hambrey Michael J. , Davies Jeremy R. , Glasser Neil F. , Waters Richard A. , Dowdeswell Julian A. , Wilby Philip R. , Wilson David , Etienne James L. 
Published: January 2005

AbstractThe depositional processes associated with late Devensian ice in areas bordering the Irish Sea basin have been the subject of considerable debate. Among the key areas around the Irish Sea, southwest Wales occupies a particularly crucial position because it is here that ice flowing from the north impinged upon the coast orthogonally and encroached inland. Two main hypotheses have emerged concerning deglaciation of the Irish Sea basin. The traditional hypothesis holds that sedimentation was ice‐marginal or subglacial, whereas an alternative hypothesis that emerged in the 1980s argued that sedimentation was glaciomarine. Southwest Wales is well‐placed to contribute to this debate. However, few detailed sedimentological studies, linked to topography, have been made previously in order to reconstruct glacial environments in this area. In this paper, evidence is presented from four boreholes drilled recently in the Cardigan area, combined with data from coastal and inland exposures in the lower Teifi valley and adjacent areas. A complex history of glaciation has emerged: (i) subglacial drainage channel formation in pre‐Devensian time, (ii) deposition of iron‐cemented breccias and conglomerates possibly during the last interglacial (or in the early/mid‐Devensian interstadial), (iii) late Devensian ice advance across the region, during which a glaciolacustrine sequence over 75 m thick accumulated, within a glacial lake known as Llyn Teifi, (iv) a second high‐level glaciolacustrine succession formed near Llandudoch, (v) outside the Teifi valley, ice‐marginal, subglacial and glaciofluvial sediments were also laid down, providing a near‐continuous cover of drift throughout the area. Glacial advance was characterized by reworking, deformation and sometimes erosion of the underlying sediments. The glaciomarine hypothesis is thus rejected for southwest Wales. Copyright © 2001 John Wiley & Sons, Ltd.
Surface‐enhanced Raman spectroscopy of insect nuclear polyhedrosis virus
Authors: Bao Pei‐Di , Huang Tian‐Quan , Liu Xin‐Ming , Wu Tie‐Qiao 
Published: January 2005

AbstractThe surface‐enhanced Raman scattering (SERS) spectra of polydrin of Trabala vishnou nuclear polyhedrosis virus (sample 1) and polydrin of Dendrolimus punctatus nuclear polyhedrosis virus (sample 2) adsorbed in silver hydrosol were investigated. The features in the adsorption mode, enhancement character and mechanism of the SERS spectra of these two samples were compared and are discussed. It was found that the molecules of sample 1 adsorbed on the silver surface through carboxyl and amino groups, and the molecules of sample 2 through the sulfur atom and also carboxyl and amino groups. The chemisorption of the molecules of both samples and their short‐range character indicate that the molecular mechanism is the primary enhancement in the SERS spectra of molecules of these two insect viruses. Copyright © 2001 John Wiley & Sons, Ltd.
The Raman spectra of Cr3O8 and Cr2O5
Authors: Maslar J. E. , Hurst W. S. , Vanderah T. A. , Levin I. 
Published: January 2005

AbstractThe Raman spectra of polycrystalline Cr3O8 and Cr2O5 powders were measured. The powders were prepared by thermal decomposition of CrO3 under flowing oxygen. Their composition was verified with x‐ray diffraction. Raman spectra were excited with both 514.5 and 647.1 nm radiation. The spectral intensities were corrected for wavelength‐dependent instrumental response. Tentative peak descriptions were made by comparison of the Cr3O8 and Cr2O5 spectra with reported spectra of crystalline chromium oxides. Copyright © 2001 John Wiley & Sons, Ltd.
Influence of nickel on hydroxyapatite crystallization
Authors: Guerra‐López J. , Pomés R. , Védova C. O. Della , Viña R. , Punte G. 
Published: January 2005

AbstractThe influence of Ni on the crystallinity and thermal stability of calcium–nickel hydroxyapatite solid solutions was studied by x‐ray diffraction, infrared and Raman spectroscopy and thermal and chemical analysis. The data reported confirm the assumption that nickel produces a reduction in the degree of crystallinity and a decrease in thermal stability of the synthesized materials. The effect of nickel on calcium Hydroxyapatite (CaHap) crystallization is similar to that exhibited by Mg and Zn. However, in this case, the substituent influence is not limited to the crystal surface and it was possible to determine its incorporation into the CaHap structure. Copyright © 2001 John Wiley & Sons, Ltd.
Non‐destructive analysis of paintings using Fourier transform Raman spectroscopy with fibre optics
Authors: Vandenabeele Peter , Verpoort Francis , Moens Luc 
Published: January 2005

AbstractIn recent decades, Raman spectroscopy has attracted increasing attention in the field of art investigation. Inorganic and organic pigments and also binding media and varnishes can be identified in various objects of art. Instead of sampling the artefacts, Raman spectroscopy, being a non‐destructive method, can be used for the direct analysis of small artefacts and gemstones. Larger artefacts, such as paintings, are not so easily examined without sampling. Therefore, the possibilities of fibre optics Fourier transform (FT) Raman analysis of paintings were explored in this work. The pigments in several paintings could be identified, even though most of these were covered with a varnish layer. The laser beam was focused through the varnish and the Raman signal of the pigments was detected. Results are presented for the fibre optics FT‐Raman investigation of paintings by Lucebert, Degas, de Chirico and Magritte. Copyright © 2001 John Wiley & Sons, Ltd.