bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expressions of nitrotyrosine and TUNEL immunoreactivities in cultured rat spinal cord neurons after exposure to glutamate, nitric oxide, or peroxynitrite
Authors: Manabe Y. , Wang J.M. , Murakami T. , Warita H. , Hayashi T. , Shoji M. , Abe K. 
Published: August 2002

AbstractAlthough excitotoxic and oxidative stress play important roles in spinal neuron death, the exact mechanism is not fully understood. We examined cell damage of primary culture of 11‐day‐old rat spinal cord by addition of glutamate, nitric oxide (NO) or peroxynitrite (PN) with detection of nitrotyrosine (NT) or terminal deoxynucleotidyl transferase‐mediated dUTP‐biotin in situ nick end labeling (TUNEL). With addition of glutamate, NOC18 (a slow NO releaser) or PN, immunoreactivity for NT became stronger in the cytoplasm of large motor neurons in the ventral horn at 6 to 48 hr and positive in the axons of the ventral horn at 24 to 48 hr. TUNEL positive nuclei were found in spinal large motor neurons from 24 hr, and the positive cell number greatly increased at 48 hr in contrast to the vehicle. Pretreatment of cultures with α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA)/kainate receptor antagonist, NO‐suppressing agent, and antioxidant protected the immunoreactivity for NT or TUNEL. The present results suggest that both excitotoxic and oxidative stress play an important role in the upregulation of NT nitration and the apoptotic pathway in cultured rat spinal neurons. J. Neurosci. Res. 65:371–377, 2001. © 2001 Wiley‐Liss, Inc.
Differential sensitivity in the survival of oligodendrocyte cell lines to overexpression of myelin proteolipid protein gene products
Authors: Bongarzone Ernesto R. , Jacobs Erin , Schonmann Vilma , Kampf Kathy , Campagnoni Celia W. , Campagnoni Anthony T. 
Published: August 2002

AbstractThe proteolipid (PLP) gene encodes at least four proteins, including the classic PLP and DM20, which are important components of the myelin sheath, and the recently identified soma‐restricted (sr) isoforms, srPLP and srDM20. The classic PLP and DM20 gene products have been implicated in oligodendrocyte survival by overexpression studies in vitro and in vivo. The classic and sr proteolipids are targeted to different cellular compartments in the oligodendrocyte, suggesting different cellular functions. Accordingly, we examined the effects of in vitro overexpression of the sr‐PLP/DM20 isoforms on the survival of stably transfected, conditionally immortalized, oligodendroglial cell lines and compared this to overexpression of the classic and the jimpy‐mutated proteolipids. The results indicate that overexpression of either normal or jimpy classic PLP/DM20 resulted in a dramatic reduction in the survival of the oligodendrocyte cell lines at the nonpermissive temperature, but not the COS‐7 cell line, a cell line expressing the same oncogene constitutively. Survival of the oligodendrocyte cell lines was significantly less affected when either the sr‐PLP/DM20 or the dopamine D‐2 receptor, another cell membrane protein, was overexpressed in the cell lines. These results suggest that overexpression of the “classic” PLP or DM20 can compromise the survival of oligodendrocytes whether or not they are mutated. Furthermore, they suggest that the internal mechanisms for normal targeting of the PLP/DM20 isoforms of either the “classic” or the “sr” types influence the oligodendrocyte's ability to survive when these proteolipids are overexpressed. J. Neurosci. Res. 65:485–492, 2001. © 2001 Wiley‐Liss, Inc.
Role of load bearing in acetylcholinesterase regulation in rat skeletal muscles
Authors: Pregelj Peter , Sketelj Janez 
Published: August 2002

AbstractSlow antigravity muscles differ from fast muscles with regard to load bearing performed during contraction. We examined the importance of load bearing in regulation of acetylcholinesterase (AChE) expression in slow and fast rat muscles. The levels of AChE mRNA in the slow soleus muscles are about 30% of those in the fast extensor digitorum longus (EDL) muscles. In the soleus muscles unloaded for 8 days by hindlimb suspension, AChE mRNA levels were not significantly different from those in the control soleus muscles. In the suspended animals, AChE transcripts in the EDL muscles decreased to about 80% of control levels. Reduction of the resting muscle tension by joint fixation did not significantly affect the levels of AChE mRNA in the unloaded soleus muscles. Phasic high‐frequency electrical stimulation of the unloaded soleus muscles via the sciatic nerve increased their AChE mRNA levels to about 50% of those in the EDL muscles. The levels observed after phasic stimulation were significantly higher than those after low‐frequency tonic stimulation, indicating the importance of muscle activation pattern for AChE regulation also in the absence of load bearing. The AChE mRNA levels in the soleus muscles overloaded for 8 days by synergist muscle ablation increased significantly to about 50% of those in the EDL muscle. The load bearing during muscle contraction seems to be a relatively unimportant extrinsic factor in the regulation of the AChE mRNA levels in muscle fibers, except when an increased load induces muscle hypertrophy accompanied by the fusion of satellite cells with the muscle fibers. © 2002 Wiley‐Liss, Inc.
New Zealand climate change information derived by multivariate statistical and artificial neural networks approaches
Authors: Mpelasoka F.S. , Mullan A.B. , Heerdegen R.G. 
Published: August 2002

AbstractClimate change impact assessment requires data at the spatial and the temporal resolution at which impacts occur. The outputs of the current global climate models (GCMs) cannot be used directly in the development of desired climate change scenarios due to their coarse resolution. Artificial neural network (ANN) and multivariate statistics (MST) models were adapted to derive changes of site precipitation and temperature characteristics in a comparative study of their potential in downscaling GCM outputs. They were calibrated and verified using observed site temperature and precipitation over New Zealand and circulation variables from the National Center for Environment Prediction (NCEP) reanalysis.Subsequently, the models were used to derive changes of mean monthly precipitation and temperature characteristics from circulation variables projected in a transient climate change experiment performed by the Hadley Centre Global Climate Model (HadCM2). HadCM2 validated well with respect to NCEP reanalysis for its ‘present climate’ simulation. The predicted changes in seasonal mean sea level pressure fields over the ‘New Zealand region’ include intensified westerly flow particularly in winter. Therefore, the HadCM2 outputs contain information that can be used to derive localized climate change characteristics.Both downscaling models capture similar general patterns of change from the same GCM output, although they show substantial differences in localized characteristics, particularly for precipitation. The MST model suggests greater warming than the ANN model but both show larger temperature rises in summer and spring than in other seasons. Precipitation changes have marked spatial variation in their magnitude and direction; although by 2070–2099 more sites show precipitation increases than decreases, except for spring, and precipitation increases are more common in the North Island than the South Island. This intercomparison of two downscaling methods demonstrates an important source of uncertainty in regional climate change scenarios in addition to differing regional responses of GCMs. Copyright © 2001 Royal Meteorological Society
The determination of observed atmospheric differences between heavy and light precipitation events in New Jersey, USA
Authors: Harnack Robert , Apffel Kirk , Georgescu Matei , Baines Shaun 
Published: August 2002

AbstractThe climatology of a limited sample of heavy precipitation events occurring in New Jersey, USA, is studied via statistical averaging and frequency histograms of environmental conditions at the event location. Also, the spatial distribution of related circulation features is examined. In addition, statistical differences between conditions accompanying the heavy (HEAVY) and a selected sample of light (LIGHT) precipitation events is determined. A large number of surface, standard level, stability and wind shear variables are employed as well as synoptic‐scale circulation features. Variables that are identified as statistically significant, after a Student's t‐test is applied to a sample mean and standard deviation are listed by season. In addition, scatter plot and composite maps are produced to illustrate conditions concurrent with the onset of heavy precipitation.In general, there are only slight differences between values obtained for the HEAVY sample and the LIGHT sample. However, the differences are large enough for some variables in some seasons that the forecaster may be able to use these results to advantage. In particular: (i) a significantly warmer and moister atmosphere at selected levels is indicated for the HEAVY sample for Autumn and Winter but not for Spring and Summer; (ii) upper‐tropospheric divergence is significantly greater in all seasons except Summer; and (iii) wind shear is significantly larger in all seasons except Summer.There is much similarity in the mean position of examined synoptic features such as troughs, vorticity maxima, jet axes and jet streaks for the two samples. However, the amplitude of circulation in the troposphere is much larger for the HEAVY sample, especially in the lower troposphere. In addition, the 850‐hPa wind maximum axis (low‐level jet indication) is much more often oriented from south to north and located within 300 km of the event location for the HEAVY cases.There was surprisingly no significant sample difference found for static stability and precipitable water in any season.Based on the results reported here, the forecaster is particularly advised to examine the tropospheric circulation amplitude and the position of low and upper‐level jet axes and jet streaks before forecasting heavy precipitation in the mid‐Atlantic region of the USA. Copyright © 2001 Royal Meteorological Society
The regional scale impact of land cover change simulated with a climate model
Authors: Zhao Mei , Pitman A. J. 
Published: August 2002

AbstractA series of 17‐year integrations using the NCAR CCM3 (at about 2.8° × 2.8° resolution) were performed to investigate the regional‐scale impact of land cover change. Our aim was to determine the impact of historical land cover change on the regional‐scale climate over the regions where most change occurred: Europe, India and China. The change from natural to current land cover was estimated using BIOME3 to predict the natural vegetation type, and then using remotely sensed data to estimate the locations where land cover had been changed through human activity. Results show statistically significant changes in the 15‐year averaged 1000 hPa wind field, mean near‐surface air temperature, maximum near‐surface air temperature and the latent heat flux over the regions where land cover change was imposed. These changes disappeared if the land cover over a particular region was omitted, indicating that our results cannot be explained by model variability. An analysis of changes on an averaged monthly time scale showed large changes in the maximum daily temperature in (Northern Hemisphere) summer and little change in the minimum daily temperature, resulting in changes in the diurnal temperature range. The change in the diurnal temperature range could be positive or negative depending on region, time of year and the precise nature of the land cover changes. Our results indicate that the inclusion of land cover change scenarios in simulations of the 20th century may lead to improved results. The impact of land cover changes on regional climates also provides support for the inclusion of land surface models that can represent future land cover changes resulting from an ecological response to natural climate variability or increasing carbon dioxide. Copyright © 2002 Royal Meteorological Society.
Comparison of different earth radiation budget experiment data sets over tropical oceans
Authors: Ho Chang‐Hoi , Chou Ming‐Dah , Sui Chung‐Hsiung 
Published: August 2002

AbstractWe compare radiation budgets derived from different Earth Radiation Budget Experiment (ERBE) archives over the tropical oceans (30S and 30N) from 1985 to 1989. Two ERBE data sets are used. One is taken from the Earth Radiation Budget Satellite (ERBS), and the other from the combined ERBS, National Oceanic and Atmospheric Administration (NOAA) 9, and NOAA 10 satellites. The domain‐mean all‐sky outgoing longwave radiation (OLR) derived from the combined data set shows a notable change in early 1987 when NOAA 10 replaced NOAA 9. This change is also found in longwave (LW) cloud radiative forcing (CRF), all‐sky shortwave (SW) radiation, and SWCRF. The ERBS, however, does not show such changes.We also examine the sensitivity of cloud–radiation interaction to the sea surface temperature (SST) of the tropical oceans. In general, each component of radiative feedbacks derived from the two ERBE data have the same sign, although they show a certain degree of discrepancy in the magnitude. The discrepancy is more notable for averaged quantities over the entire tropical oceans, particularly over the subtropics where convective activities are relatively weak. The combined data show a larger sensitivity of LWCRF and SWCRF to SST than those of the ERBS, consistent with the above results. The response of clouds to an increase in SST has a net cooling effect when using the combined data but has a net heating effect when using the ERBS data (−0.80 W m−2 K−1 versus 0.48 W m−2 K−1). Most of the discrepancies of the net CRF between the two ERBE data sets can be accounted for by the difference in the sensitivity of all‐sky OLR (4.52 W m−2 K−1 versus 1.73 W m−2 K−1). Copyright © 2002 Royal Meteorological Society.
Cold marine indicators of the late Quaternary: the new dinoflagellate cyst genus Islandinium and related morphotypes
Authors: Head Martin J. , Harland Rex , Matthiessen Jens 
Published: August 2002

AbstractRound, brown, spiny dinoflagellate cysts characterise many modern high‐latitude assemblages. Abundance is often highest where summer sea‐surface temperatures seldom exceed 7 °C and where winter sea‐surface temperatures are around 0 °C, making this morphological group important for reconstructing cold intervals within marine Quaternary sequences. Our analysis of modern sediments from the Beaufort Sea of Arctic Canada, the Kara and Laptev seas of Arctic Russia, and across the Arctic Ocean, allows us to recognise the new cyst genus Islandinium along with the extant species Islandinium minutum (Harland and Reid in Harland et al., 1980) new combination (basionym: Multispinula? minuta), Islandinium? cezare (de Vernal et al., 1989 ex de Vernal in Rochon et al., 1999) new status and combination (basionym: Multispinula? minuta var. cezare) sensu lato, and Echinidinium karaense new species. Of these, the generotype Islandinium minutum is a well‐known but morphologically problematic species. We have re‐examined the type material from the Beaufort Sea and studied specimens from across the Arctic, and our observations clarify ambiguities in the original description of this species. The archeopyle of Islandinium minutum results from the loss of three apical plates, an unusual style among peridiniphycidean dinoflagellates. The asymmetrical location of these plates around the apex is distinctive, and probably contributed to earlier misunderstandings of the archeopyle. Previous attributions to Multispinula? and Algidasphaeridium? are unsustainable. Maps showing the distribution of Islandinium minutum are given for the Northern Hemisphere and show this species to be polar to north‐temperate, whereas Islandinium? cezare s.l. and Echinidinium karaense appear to be more restricted to polar environments. Copyright © 2001 John Wiley & Sons, Ltd.
Changes in the porous silicon structure induced by laser radiation
Authors: Salcedo Walter Jaimes , Ramirez Fernandez Francisco J. , Rubim Joel C. 
Published: August 2002

AbstractPorous silicon (PS) films were investigated by Raman, and photoluminescence spectroscopies using different laser excitations at 488.0, 514.5, 632.8, and 782.0 nm. The exposure of PS layers to high laser powers causes an increase in the 480 cm−1 Raman intensity and a shift and enhancement of the PL emission. A laser‐assisted surface reaction is proposed to explain these observations. The analysis of the first‐ and second‐order Raman spectra showed that the band gaps of the PS films are indirect as in bulk c‐Si. The Raman phonon and the PL spectra and also the spectral distribution of the linear polarization degree (LPD) of PS layers were shown to be dependent on the laser excitation energy. This dependence cannot be explained within the quantum confinement model. A mechanism for the PL emission in PS layers is presented in which the radioactive recombination of electron–hole pairs occurs in localized centres (the Si—O—SiR moieties) at the pore/crystallite interface. These quasi‐molecular centres are Jahn–Teller active, i.e. the radioactive recombination is a phonon‐assisted phenomenon. Copyright © 2001 John Wiley & Sons, Ltd.
Low‐wavenumber Raman scattering spectroscopy in studies of new gallium‐doped silica glass‐based transparent vitroceramic medium
Authors: Ceccato R. , Maschio R. Dal , Ferrari M. , Gialanella S. , Lipinska‐Kalita K. E. , Mariotto G. , Montagna M. , Ohki Y. , Rossi F. 
Published: August 2002

AbstractOptically transparent, silica glass‐based vitroceramic material doped with gallium oxide was obtained by standard glass fusion and appropriate thermal treatments. Low‐wavenumber Raman scattering spectroscopy allowed the determination of the microstructure and in particular the size distribution of nanoparticles embedded in the amorphous matrix. The nanocrystal growth was accurately controlled by heat treatment conditions. Transmission electron microscopy and X‐ray diffraction measurements revealed the presence of a single crystalline phase, spherical‐shaped nanoaggregates, homogeneously distributed in the transparent composite medium. Copyright © 2001 John Wiley & Sons, Ltd.
Resonance Raman spectroscopic study of the neutral flavin radical complex of DNA photolyase from Escherichia coli
Authors: Murgida Daniel H. , Schleicher Erik , Bacher Adelbert , Richter Gerald , Hildebrandt Peter 
Published: August 2002

AbstractThe neutral flavin radical complex of DNA photolyase from Escherichia coli was studied by resonance Raman spectroscopy for the first time. The experiments were carried out with enzyme variants that lack the light‐harvesting methenyltetrahydrofolate cofactor so that the resonance Raman spectra exclusively display the vibrational bands of the flavin radical in the catalytic site. Spectral changes induced upon H–D exchange and upon substituting the natural flavin by its 15N‐labelled isotopomer allow a tentative assignment of the prominent bands in the region between 1200 and 1650 cm−1. It is shown that most of the bands observed with 568 nm excitation originate from modes localized in the isoalloxazine ring. In conjunction with previous data on flavin radicals, the present results allow the identification of the marker bands that appear to be particularly sensitive towards changes in the electron density distribution of this ring and, hence, reflect the specific intermolecular interactions in the catalytic site. Copyright © 2001 John Wiley & Sons, Ltd.
In situ Raman monitoring of chromium oxide scale growth for stress determination
Authors: Mougin Julie , Rosman Noël , Lucazeau Guy , Galerie Alain 
Published: August 2002

AbstractRaman spectra of a growing chromia (Cr2O3) layer generated by oxidation of pure chromium at 750 °C under 150 mbar of oxygen were recorded in situ every 5 min. The wavenumber evolution of the main Raman band versus oxidation time was interpreted in terms of mechanical stress development. Comparison with Raman spectra of a fully relaxed spalled chromia layer submitted to high‐pressure and high‐temperature treatments showed that internal compressive stresses develop during the growth, varying from −2.1 GPa when the scale is very thin to −2.4 GPa when the scale reaches a thickness of 0.6 µm. Relaxation phenomena seem to take place during isothermal oxidation. During cooling, thermal stresses are induced, which are purely elastic according to the perfect reversibility of cooling–heating cycles. Copyright © 2001 John Wiley & Sons, Ltd.
How to determine the pressure of a methane‐containing gas mixture by means of two weak Raman bands, ν3 and 2ν2
Authors: Brunsgaard Hansen S. , Berg R. W. , Stenby E. H. 
Published: August 2002

AbstractRaman spectra of a pure CH4 sample, two CH4C2 H6 mixtures and a CH4N2 mixture were obtained as a function of pressure at pressures up to 39.6 MPaA (MPa absolute). These spectra are presented in the region 3120–2980 cm−1. A clear pressure dependence of the area ratio between two weak methane bands, ν3 (asymmetric CH stretching) and 2ν2 (overtone of the asymmetric CH bending), is observed; the methane ν3 band intensity is lowered relative to the methane 2ν2 as the pressure is raised. The intensity ratios between these two bands, I(ν3)/I(2ν2), were determined and plotted as a function of pressure. Surprisingly it is observed that the ratio at a fixed pressure is independent of the composition and thereby of the surroundings in which the methane molecule is vibrating. A model function to predict the pressure is given. From a practical point of view, the present results could be useful for determining directly the total pressure in methane mixtures the composition of which is not known. Copyright © 2002 John Wiley & Sons, Ltd.
Raman spectroscopic study of azurite and malachite at 298 and 77 K
Authors: Frost R. L. , Martens W. N. , Rintoul L. , Mahmutagic E. , Kloprogge J. T. 
Published: August 2002

AbstractAzurite [Cu2+3(CO3)2(OH)2] and malachite [Cu2+2(CO3)(OH)2] are both monoclinic hydroxy carbonates of copper. The Raman spectra of these two minerals were collected at both 298 and 77 K together with the single crystal Raman spectra of azurite at 298 K. The spectra of both azurite and malachite contain modes of three separate vibrational groups: OH, CO3 and Cu O. Accordingly, for azurite the bands at 3453 and 3427 cm−1 have been assigned as the O H stretching mode with the O H bending modes found at 1035 and 952 cm−1. Malachite displays two hydroxyl stretching bands at 3474 and 3404 cm−1 at 298 K which shift to 3470 and 3400 cm−1 at 77 K while O H out‐of‐plane bending modes are found at 1045 and 875 cm−1. For the carbonate group, bands are observed at 1090 cm−1 (ν1), 837 and 817 cm−1 (ν2), 1490 and 1415 cm−1 (ν3) and 769 and 747 cm−1 (ν4). The effect of collecting the spectra at 77 K results in considerable band narrowing. The Raman spectra of the single crystals of azurite show the orientation dependence of the vibrational modes. A mechanism for ν2 splitting is proposed whereby vertical carbonate ions couple to form an in‐phase and out‐of‐phase bending modes. Combination of these vibrational modes such as ν1 + ν3, ν1 + ν3, ν1 + ν4 and 2ν2 are found at 2530, 2414, 1860, and 1670 cm−1, respectively. IR bands for the Cu O stretching modes are observed at 495 and 400 cm−1, while Cu O bending modes occur at 455 and 345 cm−1. Bands at 305 and 240 cm−1 are assigned to the O Cu OH bending modes. The Raman out‐of‐plane bending modes are found at 194 and 170 cm−1. For the carbonate group, infrared bands are observed at 1095 cm−1 (ν1), 834 and 816 cm−1(ν2), 1430 and 1419 cm−1 (ν3) and 764 and 739 cm−1 (ν4). Combination of the CO3 vibrational modes ν1 + ν4 is observed at 1860 cm−1. IR bands for Cu O stretching modes are observed at 580, 570 and 505 cm−1. Copyright © 2002 John Wiley & Sons, Ltd.