bluuebunny/crossref_metadata_2025_split huggingface dataset:
13C and 1H MAS NMR Study of Benzene and p-Xylene in Zeolites and a Mesoporous Material FSM-16
Authors: Satozawa Masatoshi , Kunimori Kimio , Hayashi Shigenobu 
Published: June 2006

Abstract
13C and 1H MAS NMR spectra have been measured at room temperature for benzene and p-xylene adsorbed in H-ZSM-5, Na-, and H-type mordenites with different Si/Al2 ratios, H-Y, Na-Y, Na-X, and FSM-16 to study the dynamics of the guest species in the host materials. The second moments M2 evaluated from the SSB intensity in 13C CP/MAS NMR spectra were used to predict the motion of the guest species. Benzene molecules rotate about the C6 axis freely, and reorientation of the C6 axis takes place in H-ZSM-5. The para axis of p-xylene molecule is fixed in H-ZSM-5. The reorientations of the guest species become isotropic in the faujasite-type zeolites, Na-Y, H-Y, and Na-X. In FSM-16, translation diffusion takes place in addition to the isotropic rotation like in the liquid state. The mobilities of benzene molecules are in the following order, mordenite &lt; H-ZSM-5 &lt; Na-Y &lt; Na-X &lt; H-Y &lt; FSM-16, while those of p-xylene molecules are in the following order. H-ZSM-5 &lt; mordenite &lt; Na-Y &lt; Na-X ≈ H-Y &lt; FSM-16. There is a good correlation between the pore size and the mobility of the guest species, with the exception of the mordenite/benzene systems.
Low Multielectron Reduction Potentials of Emerald Green [60]Fullerenes
Authors: Canteenwala Taizoon , Li Wenguang , Wang Hsing-Ling , Chiang Long Y 
Published: June 2006

Abstract
Unique double-triphenylene interconnected all-trans 18-trannulene electronic configuration of dodecaethylated emerald green fullerene (EFn), C60[–C(CH3)(CO2Et)2]6 or EF-6MC2, allows the fullerene cage to retain similar affinity for electrons as C60 and high multielectron accepting capability with E1Red = −0.36 V, E2Red = −0.88 V, and E3Red = −1.45 V vs. Ag/AgCl.
Greenish-yellow Light-emitting, Long-lasting Phosphorescence in Eu2+-doped CaO–CaBr2–SiO2 Phosphor System
Authors: Xia Zhiguo , Li Qiang , Sun Jiayue 
Published: June 2006

Abstract
Novel greenish-yellow light long-lasting afterglow material, Eu2+-doped CaO–CaBr2–SiO2 phosphor system, is prepared by the conventional high-temperature solid-state method. Photoluminescence (PL) spectrum reveals that it exhibits a strong blue emission band centered at 469 nm with some asymmetry on the long wavelength side, while this phosphor emits greenish-yellow light and shows strong long-lasting phosphorescence after it is excited with 365-nm UV light. The phosphorescence lasts for more than 1 h in the light perception of the dark-adapted human eye (0.32 mcd/m2). The possible phosphorescence mechanism is also investigated.
Selective Hydrogenation of Naphthols to Tetralones over Supported Palladium Catalysts in Supercritical Carbon Dioxide Solvent
Authors: Mine Eiichi , Hiyoshi Norihito , Sato Osamu , Rode Chandrashekhar V , Shirai Masayuki 
Published: June 2006

Abstract
Naphthols were selectively hydrogenated to the corresponding tetralones over supported palladium metal catalysts in supercritical carbon dioxide solvent.
Organic Nanoparticles of Porphyrin without Self-aggregation
Authors: Ou Zhong-min , Yao Hiroshi , Kimura Keisaku 
Published: June 2006

Abstract
Well-dispersed organic nanoparticles of porphyrin with narrow size distribution were successfully prepared in aqueous solution based on the “ion-association” method. No self-aggregation of the constituent porphyrin chromophores was confirmed. The nanoparticles exhibit interesting optical properties; a large bathochromic shift in the absorption and a remarkable resolution increase in the fluorescence compared to those for the corresponding aqueous-phase porphyrin.
Effects of aerosols on trade wind cumuli over the Indian Ocean: Model simulations
Authors: Mcfarquhar Greg M. , Wang Hailong 
Published: June 2006

AbstractAn Eulerian non‐hydrostatic anelastic fluid model using a warm cloud bulk parametrization is used to study responses of trade wind cumuli to increased cloud drop concentrations produced by enhanced aerosol numbers and to absorption from aerosols containing soot. Simulations are initialized using temperature and moisture profiles measured during the Indian Ocean Experiment (INDOEX) and sea surface temperatures retrieved from the Tropical Rainfall Measuring Mission microwave imager. Cloud covers between 4 and 10% and cloud‐averaged liquid water contents of between 0.01 and 0.6 g m−3 more closely match values retrieved and measured in situ during INDOEX than those modelled in past studies; previous studies found larger cloud coverage associated with cloud spreading below a strong inversion not present in the INDOEX soundings.As in previous studies, a diurnal cycle with reductions of cloud cover and liquid water path (LWP) after sunrise is seen, with absorbing aerosols within cloud augmenting the decrease in cloud cover. Variations in aerosol vertical profiles can change semi‐direct radiative forcing at the surface (top of the atmosphere) from +1.6(+1.3)W m−2 when aerosols are confined to cloud compared to −0.4(−0.6)W m−2 when aerosols occur below cloud. Low‐level water‐vapour mixing ratios decrease as vertical motions increase, the vertical motions being enhanced by below‐cloud solar heating and cloud‐top radiative cooling and suppressed by in‐cloud heating. Cloud cover and LWP are larger for stronger vertical motions, explaining the dependence of radiative forcing on aerosol profile. In the late afternoon and evening, increases in radiative cooling and sensible and latent heat flux, occurring due to reductions in mixed‐layer temperature and vapour, allow cloud cover and LWP to recover to values like those found in simulations without absorbing aerosols. Copyright © 2006 Royal Meteorological Society.
Observations of the depth of ice particle evaporation beneath frontal cloud to improve NWP modelling
Authors: Forbes Richard M. , Hogan Robin J. 
Published: June 2006

AbstractThe evaporation (sublimation) of ice particles beneath frontal ice cloud can provide a significant source of diabatic cooling which can lead to enhanced slantwise descent below the frontal surface. The strength and vertical extent of the cooling play a role in determining the dynamic response of the atmosphere, and an adequate representation is required in numerical weather‐prediction (NWP) models for accurate forecasts of frontal dynamics. In this paper, data from a vertically pointing 94 GHz radar are used to determine the characteristic depth‐scale of ice particle sublimation beneath frontal ice cloud. A statistical comparison is made with equivalent data extracted from the NWP mesoscale model operational at the Met Office, defining the evaporation depth‐scale as the distance for the ice water content to fall to 10% of its peak value in the cloud. The results show that the depth of the ice evaporation zone derived from observations is less than 1 km for 90% of the time. The model significantly overestimates the sublimation depth‐scales by a factor of between two and three, and underestimates the local ice water content by a factor of between two and four. Consequently the results suggest the model significantly underestimates the strength of the evaporative cooling, with implications for the prediction of frontal dynamics. A number of reasons for the model discrepancy are suggested. A comparison with radiosonde relative humidity data suggests part of the overestimation in evaporation depth may be due to a high RH bias in the dry slot beneath the frontal cloud, but other possible reasons include poor vertical resolution and deficiencies in the evaporation rate or ice particle fall‐speed parametrizations. © Royal Meteorological Society, 2006. The contribution of R. M. Forbes is Crown copyright..
Simulations of low‐level convergence lines over north‐eastern Australia
Authors: Thomsen Gerald L. , Smith Roger K. 
Published: June 2006

AbstractWe describe high‐resolution numerical model simulations of low‐level convergence lines over north‐eastern Australia using the Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5). The simulations are for selected events that were documented during the Gulf Lines Experiment, held in September–October 2002. The calculations provide further insights into the dynamics of the convergence lines and the mechanisms involved in their formation. In particular they show two clearly distinct convergence lines, one that corresponds to the morning glory and one which corresponds to the North Australian Cloud Line; the former originates from the east‐coast sea breeze over Cape York Peninsula south of about 14°S, while the latter originates from the east‐coast sea breeze north of this latitude. They support also a recently proposed conceptual model for the generation of southerly morning glories and show for the first time the separation of a bore‐like disturbance following the collision of a nocturnal cold front to the south of the inland trough with a sea‐breeze front to the north of the trough. Moreover, they show the progressive transition of the east‐coast sea‐breeze front and the inland cold front from gravity‐current‐like flows to bore‐like disturbances overnight to form north‐easterly and southerly morning glories, respectively. Copyright © 2006 Royal Meteorological Society.
An estimate of the global impact of multiple scattering by clouds on outgoing long‐wave radiation
Authors: Costa S. M. S. , Shine K. P. 
Published: June 2006

AbstractAlthough the potential importance of scattering of long‐wave radiation by clouds has been recognised, most studies have concentrated on the impact of high clouds and few estimates of the global impact of scattering have been presented. This study shows that scattering in low clouds has a significant impact on outgoing long‐wave radiation (OLR) in regions of marine stratocumulus (−3.5 W m−2 for overcast conditions) where the column water vapour is relatively low. This corresponds to an enhancement of the greenhouse effect of such clouds by 10%. The near‐global impact of scattering on OLR is estimated to be −3.0 W m−2, with low clouds contributing −0.9 W m−2, mid‐level cloud −0.7 W m−2 and high clouds −1.4 W m−2. Although this effect appears small compared to the global mean OLR of 240 W m−2, it indicates that neglect of scattering will lead to an error in cloud long‐wave forcing of about 10% and an error in net cloud forcing of about 20%. Copyright © 2006 Royal Meteorological Society.
An improved implicit predictor–corrector scheme for boundary layer vertical diffusion
Authors: Diamantakis Michail , Wood Nigel , Davies Terry 
Published: June 2006

AbstractTime integration of the parametrized boundary layer vertical diffusion in models of the atmosphere, used in numerical weather prediction (NWP) and climate modelling, can produce noise which appears as two‐time‐step oscillations in boundary layer tendencies. The origin of this noise was considered by Kalnay and Kanamitsu who analysed a number of schemes, two of which were based on a predictor–corrector approach. Here, a generalization of these two schemes is presented which results in unconditional stability for practical NWP vertical diffusion problems. The proposed generalization improves the stability of the original schemes. Asymptotic error analysis shows that this improvement is achieved without loss of accuracy, and that a small reduction in the leading error term is possible. Second‐order accuracy is feasible but in this case unconditional stability can be achieved only for linear or mildly nonlinear problems. Numerical experiments and model simulations support the analysis presented in this paper. The limitations and strengths of the scheme are exposed and suggestions for a practical implementation are made. This scheme is ideally suited as a component of a more general predictor–corrector algorithm for the problem of physics–dynamics coupling, for example that of Cullen and Salmond. © Crown copyright, 2006.
Verification region selection and data assimilation for adaptive sampling
Authors: Bishop Craig H. , Etherton Brian J. , Majumdar Sharanya J. 
Published: June 2006

AbstractAdaptive or targeted observations supplement routine observations at a pre‐specified targeting time. Adaptive observation locations are selected to supplement routine observations in an attempt to minimize the forecast error variance of a future target forecast within some predefined verification region (VR) at some predefined verification time. Ideally, the VR is placed in a location where unusually large forecast errors are likely. Here, we compare three methods of selecting VRs: a climatological method based on seasonal averages of forecast errors; an unconditioned method based on verification time ensemble spread; and a conditioned method based on an ensemble transform Kalman filter (ETKF) estimate of forecast error variance given the routine observations to be taken at the targeting time. To test the effectiveness of the three approaches, observation‐system simulation experiments on a chaotic barotropic flow were performed using an imperfect model. To test the sensitivity of our results to the type of forecast error covariance model used in the data assimilation (DA) scheme, two types of DA schemes were tested: an isotropic and a hybrid scheme. For isotropic DA, correlations between vorticity forecast errors at any two points were solely a function of the distance between the points; for hybrid DA, the forecast error covariance matrix was a linear combination of the covariance matrix used in isotropic DA and the sample covariance matrix of an ETKF ensemble. For each of the three VRs, the ETKF was used to select two adaptive observations. To assess targeted‐observation‐induced error reductions, forecast errors with and without targeted observations were computed for the VR, the total domain and also for an empirical VR which was defined to be the VR with the largest forecast error without targeted observations. The sensitivity, to the type of DA scheme employed, of the ETKF's ability to distinguish high‐impact targeted observations from low‐impact observations, was also examined. Amongst other things, it was found that: conditioned VRs were more prone to large errors than the other VRs; and the targeted‐observation‐induced reduction in forecast error variance was largest when hybrid DA and conditioned VRs were used, as was the range of forecast impacts distinguished by ETKF predictions. Copyright © 2006 Royal Meteorological Society.
Dynamics of the MAP IOP 15 severe Mistral event: Observations and high‐resolution numerical simulations
Authors: Guéenard V. , Drobinski P. , Caccia J. L. , Tedeschi G. , Currier P. 
Published: June 2006

AbstractThis paper investigates the fundamental processes involved in a severe Mistral event that occurred during the Mesoscale Alpine Program (from 6 to 9 November 1999). The Mistral refers to a violent north/north‐westerly wind blowing in south‐eastern France from the Rhône valley to the French Riviera. The study is based on measurements from radiosoundings launched from Lyon and Nîmes and from two UHF wind profilers located near Marseille and Toulon allowing a good description of the flow in the complex terrain formed by the southwestern Alps. Observational results are compared with RAMS non‐hydrostatic numerical simulations performed with 27 km, 9 km and 3 km nested grids. The numerical simulations capture the flow complexity both upstream of the Alps and in the coastal area affected by the Mistral. They correctly reproduce horizontal wind speeds and directions, vertical velocities, virtual potential temperature and relative humidity documented by the observational network. The simulations are used to point out the main dynamical processes generating the Mistral. It is found that flow splitting around the Alps and around the isolated peaks bordering the south‐eastern part of the Rhône valley (Mont Ventoux 1909 m, Massif du Lubéron 1425 m) induces the low‐level jet observed near Marseille that lasts for 36 hours. The high‐resolution simulation indicates that the transient low‐level jet lasting for only 9 hours observed at Toulon is due to a gravity wave breaking over local topography (the Sainte Baume 1147 m) where hydraulic jumps are involved. A mountain wake with two opposite‐sign potential‐vorticity banners is generated. The mesoscale wake explains the westward progression of the large‐scale Alpine wake. Copyright © 2006 Royal Meteorological Society.
Low potential for stratospheric dynamical change to be implicated in the large winter warming in the central Antarctic Peninsula
Authors: Roscoe H. K. , Marshall G. J. , King J. C. 
Published: June 2006

AbstractStratospheric change associated with the Antarctic ozone hole is clearly implicated in changing surface climate near 65°S in late summer, in both measurements and models, via downward propagation of height anomalies following the final warming. But one of the largest changes in surface temperature in Antarctica has occurred in the Antarctic Peninsula at 60 to 65°S in winter, and most of the change at 65°S occurred before the ozone hole. Stratospheric change can cause tropospheric change in Antarctic winter by modifying the reflection and refraction of planetary waves, whereby a stronger stratospheric vortex moves the tropospheric jets polewards, which can modify the Southern Annular Mode (SAM) in surface pressure that forces the tropospheric circumpolar winds. We examine stratospheric influence on the SAM in winter by inter‐annual correlation of the SAM with the solar‐cycle and volcanic aerosols, which act to change forcing of the stratospheric vortex in winter. Correlations are a maximum in June (midwinter) and are significant then, but are poor averaged over winter months. Hence the potential of change in the stratosphere to change Antarctic tropospheric climate in winter by dynamical means is low. This negative result is important given the proven high potential for change in summer by dynamical means. Copyright © 2006 Royal Meteorological Society.
Radar scattering by aggregate snowflakes
Authors: Westbrook C. D. , Ball R. C. , Field P. R. 
Published: June 2006

AbstractThe radar scattering properties of realistic aggregate snowflakes have been calculated using the Rayleigh–Gans theory. We find that the effect of the snowflake geometry on the scattering may be described in terms of a single universal function, which depends only on the overall shape of the aggregate and not the geometry or size of the pristine ice crystals which compose the flake. This function is well approximated by a simple analytic expression at small sizes; for larger snowflakes we fit a curve to our numerical data. We then demonstrate how this allows a characteristic snowflake radius to be derived from dual wavelength radar measurements without knowledge of the pristine crystal size or habit, while at the same time showing that this detail is crucial to using such data to estimate ice water content. We also show that the ‘effective radius’, characterizing the ratio of particle volume to projected area, cannot be inferred from dual wavelength radar data for aggregates. Finally, we consider the errors involved in approximating snowflakes by ‘air–ice spheres', and show that for small enough aggregates the predicted dual wavelength ratio typically agrees to within a few percent, provided some care is taken in choosing the radius of the sphere and the dielectric constant of the air–ice mixture; at larger sizes the radar becomes more sensitive to particle shape, and the errors associated with the sphere model are found to increase accordingly. Copyright © 2006 Royal Meteorological Society.
Ablation of Proliferating Marrow with 5-Fluorouracil Allows Partial Purification of Mesenchymal Stem Cells
Authors: Wang Zhuo , Song Junhui , Taichman Russell S. , Krebsbach Paul H. 
Published: June 2006

Abstract
The ability to identify and maintain mesenchymal stem cells in vitro is a prerequisite for the ex vivo expansion of cells capable of effecting mesenchymal tissue regeneration. The aim of this investigation was to develop an assay to enrich and ultimately purify mesenchymal stem cells. To enrich the population of mesenchymal stem cell-like cells, rats or mice were administered 5-fluorouracil (5-FU) in vivo. Limiting dilution analysis demonstrated that 5-FU-treated bone marrow had the potential to form colony-forming units-fibroblastic (CFU-F) at a 10-fold or sixfold enrichment compared to normal bone marrow in rats or mice, respectively. In vivo and in vitro differentiation assays supported the enrichment and purification effects. In vitro, bone marrow cultures from 5-FU-treated bone marrow demonstrated lineage-specific gene expression in lineage-specific medium conditions in contrast to the multilineage gene expression of control bone marrow cultures. In vivo implantation of 5-FU-treated cells that were not expanded in culture generated ossicles containing an intact bone cortex and mature hematopoietic components, whereas non-5-FU-treated bone marrow only formed fibrous tissues. Our results demonstrate that enrichment of a quiescent cell population in the bone marrow by in vivo treatment of 5-FU spares those undifferentiated mesenchymal stem cells and influences the differentiation of bone marrow stromal cells in vitro and in vivo. This prospective identification of a population of mesenchymal cells from the marrow that maintain their multilineage potential should lead to more focused studies on the characterization of a true mesenchymal stem cell.
Splenic Endothelial Cell Lines Support Development of Dendritic Cells from Bone Marrow
Authors: Despars Geneviève , O'Neill Helen C. 
Published: June 2006

Abstract
Although growth factors are commonly used to generate dendritic cells (DCs) in vitro, the role of the microenvironment necessary for DC development is still poorly understood. The mixed splenic stromal cell population STX3 defines an in vitro microenvironment supportive of DC development. Dissection of cellular components of the STX3 stroma should provide information about a niche for DC development. STX3 was therefore cloned by single-cell sorting, and a panel of 102 splenic stromal cell lines was established. Four representative splenic stromal cell lines that support hematopoiesis from bone marrow are described here in terms of stromal cell type and DC production. All four stromal lines express the endothelial genes Acvrl1, Cd34, Col18a1, Eng, Flt1, Mcam, and Vcam1 but not Cd31 or Vwf. Three of the four lines form tube-like structures when cultured on Matrigel. Their endothelial maturity correlates with the ability to support myeloid DC development from bone marrow. A fourth cell line, unable to form tube-like structures in Matrigel, produced large granulocytic cells expressing CD11b and CD86 but not CD11c and CD80. Conditioned media from splenic stromal cell lines also support DC production, indicating that soluble growth factors and cytokines produced by stromal lines drive DC development. This article reports characterization of immature endothelial cell lines derived from spleen that are supportive of DC development and predicts the existence of such a cell type in vivo which regulates DC development within spleen.
Linear Filtering and Recursive Credibility Estimation
Authors: Zehnwirth Ben 
Published: June 2006

AbstractRecursive credibility estimation is discussed from the viewpoint of linear filtering theory. A conjunction of geometric interpretation and the innovation approach leads to general algorithms not developed before. Moreover, covariance characterizations considered by other researchers drop our elegantly as a result of geometric considerations. Examples are presented of Kalman type filters valid for non-Gaussian measurements.