bluuebunny/crossref_metadata_2025_split huggingface dataset:
An evaluation of the long‐wave radiative transfer code used in the Met Office Unified Model
Authors: Goldblatt C. , Lenton T. M. , Watson A. J. 
Published: April 2009

AbstractA detailed evaluation of the radiative transfer code used in the Met Office Unified Climate/Forecast Model is performed, comparing it with a line‐by‐line model and testing the climatic effects of errors in a radiative‐‐convective model. The radiative forcing at the tropopause due to CO2 changes within SRES scenarios and across Quaternary glacial cycles is represented with reasonable accuracy, suggesting that surface temperature will be correctly predicted. However, this is achieved by partial cancellation of opposing errors in upward and downward fluxes. The changes in the vertical profiles of radiative fluxes and the changes to surface and top‐of‐atmosphere fluxes all show significant errors, even at twice pre‐industrial CO2. This causes a sign error in the change in the convective flux in the radiative‐‐convective model. Performance of the code deteriorates rapidly above four times pre‐industrial CO2. For less‐abundant greenhouse gases, CH4 and N2O, the errors are larger as a proportion of their radiative forcings. Errors for surface and top‐of‐atmosphere fluxes for CO2 are similar to those from the mean of the general circulation model (GCM) codes submitted to the intercomparison of radiation codes for IPCC AR4, implying that errors as found here may not be uncommon in climate models. A renewed emphasis on accuracy in radiative transfer calculations and openness in intercomparison studies is necessary to improve the modelling of climate change. Copyright © 2009 Royal Meteorological Society
A Gill–Matsuno‐type mechanism explains the tropical Atlantic influence on African and Indian monsoon rainfall
Authors: Kucharski F. , Bracco A. , Yoo J. H. , Tompkins A. M. , Feudale L. , Ruti P. , Dell'Aquila A. 
Published: April 2009

AbstractRecent studies using coupled atmosphere–ocean models have shown that the tropical Atlantic has a significant impact on the Indian monsoon. In this article, the observational basis for this teleconnection is examined and the physical mechanism responsible for bridging sea‐surface temperatures (SSTs) in the Atlantic and precipitation over India is investigated with idealized atmospheric general circulation model (AGCM) experiments in which constant SST anomalies are prescribed and ‘switched on’ in the tropical Atlantic region. A simple Gill–Matsuno‐type quadrupole response is proposed to explain the teleconnection between the tropical Atlantic and the Indian basin, with an enforcement of the eastward response likely due to nonlinear interactions with the mean monsoon circulation. The simplicity of this mechanism suggests the reproducibility of this result with a broad range of AGCMs. Copyright © 2009 Royal Meteorological Society
Vertical velocity variance and skewness in clear and cloud‐topped boundary layers as revealed by Doppler lidar
Authors: Hogan Robin J. , Grant Alan L. M. , Illingworth Anthony J. , Pearson Guy N. , O'Connor Ewan J. 
Published: April 2009

AbstractIn this paper, observations by a ground‐based vertically pointing Doppler lidar and sonic anemometer are used to investigate the diurnal evolution of boundary‐layer turbulence in cloudless, cumulus and stratocumulus conditions. When turbulence is driven primarily by surface heating, such as in cloudless and cumulus‐topped boundary layers, both the vertical velocity variance and skewness follow similar profiles, on average, to previous observational studies of turbulence in convective conditions, with a peak skewness of around 0.8 in the upper third of the mixed layer. When the turbulence is driven primarily by cloud‐top radiative cooling, such as in the presence of nocturnal stratocumulus, it is found that the skewness is inverted in both sign and height: its minimum value of around −0.9 occurs in the lower third of the mixed layer. The profile of variance is consistent with a cloud‐top cooling rate of around 30 W m−2. This is also consistent with the evolution of the thermodynamic profile and the rate of growth of the mixed layer into the stable nocturnal boundary layer from above. In conditions where surface heating occurs simultaneously with cloud‐top cooling, the skewness is found to be useful for diagnosing the source of the turbulence, suggesting that long‐term Doppler lidar observations would be valuable for evaluating boundary‐layer parametrization schemes. Copyright © 2009 Royal Meteorological Society
Life cycle of the QBO‐modulated 11‐year solar cycle signals in the Northern Hemispheric winter
Authors: Lu Hua , Gray Lesley J. , Baldwin Mark P. , Jarvis Martin J. 
Published: April 2009

AbstractThis paper provides some insights on the quasi‐biennial oscillation (QBO) modulated 11‐year solar cycle (11‐yr SC) signals in Northern Hemisphere (NH) winter temperature and zonal wind. Daily ERA‐40 Reanalysis and ECMWF Operational data for the period of 1958–2006 were used to examine the seasonal evolution of the QBO‐solar cycle relationship at various pressure levels up to the stratopause. The results show that the solar signals in the NH winter extratropics are indeed QBO‐phase dependent, moving poleward and downward as winter progresses with a faster descent rate under westerly QBO than under easterly QBO. In the stratosphere, the signals are highly significant in late January to early March and have a life span of ∼30–50 days. Under westerly QBO, the stratospheric solar signals clearly lead and connect to those in the troposphere in late March and early April where they have a life span of ∼10 days. As the structure changes considerably from the upper stratosphere to the lower troposphere, the exact month when the maximum solar signals occur depends largely on the altitude chosen.For the low‐latitude stratosphere, our analysis supports a vertical double‐peaked structure of positive signature of the 11‐yr SC in temperature, and demonstrates that this structure is further modulated by the QBO. These solar signals have a longer life span (∼3–4 months) in comparison to those in the extratropics. The solar signals in the lower stratosphere are stronger in early winter but weaker in late winter, while the reverse holds in the upper stratosphere. Copyright © 2009 Royal Meteorological Society
Delocalization in valence bond—Hyperconjugation
Authors: Havenith R. W. A. , van Lenthe J. H. 
Published: April 2009

AbstractWe consider delocalization in small molecules. The valence bond technology allows an arbitrary division of the 1‐electron space in strictly separate, but nonorthogonal, spaces. Allowing or obstructing orbital mixing between subspaces during the SCF procedure is associated with incorporating or eliminating the hyperconjugation effect. We show an example for tert‐butyl and trimethylsilyl cations and radicals. For H2, for which really extensive basis sets are feasible, we extend the basis so far that the delocalization or hyperconjugation effect has nearly disappeared. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Study of the discontinuity of the exchange‐correlation potential in an exactly soluble case
Authors: Gori‐Giorgi Paola , Savin Andreas 
Published: April 2009

AbstractIt was found by Perdew et al. (Phys Rev Lett, 1982, 49, 1691) and by Sham and Schlüter (Phys Rev Lett. 1983, 51, 1884) that the exact Kohn–Sham exchange‐correlation potential of an open system may jump discontinuously as the particle number crosses an integer, with important physical consequences. Recently, Sagvolden and Perdew (Phys Rev A 2008, 77, 012517) have analyzed the discontinuity of the exchange‐correlation potential as the particle number crosses one, with an illustration that uses a model density for the H− ion. In this work, we extend their analysis to the case in which the external potential is the simple harmonic confinement, choosing spring‐constant values for which the two‐electron hamiltonian has an analytic solution. This way, we can obtain the exact, analytic, exchange and correlation potentials for particle number fluctuating between zero and two, illustrating the discontinuity as the particle number crosses one without introducing any model or approximation. We also discuss exchange and correlation separately. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Geometrically faithful homeomorphisms between the electron density and the bare nuclear potential
Authors: Popelier Paul L. A. , Brémond Éric A. G. 
Published: April 2009

AbstractThe topology of the nuclear potential,Vnuc(r), of just over 130 molecules and molecular complexes is investigated and compared with the topology of the electron density ρ(r). As nuclear positions are kept fixed in this comparison, this work screens forgeometrically faithfulhomeomorphisms between ρ(r) andVnuc(r). In this set of molecules spanning simple inorganic moieties, strained (and cyclic) hydrocarbons, (fused) aromatics, boranes, van der Waals complexes, water clusters, and a few biomolecules, about 70% of the systems show this homeomorphism. A simple analytical formula is derived, expressing the position of a (3,−1) critical point in any diatomic as a function of the participating atomic numbers. The topology ofVnuc(r) at one location of a molecule can sensitively depend on the presence or absence of a substituent far away from this location. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Coverage path planning algorithms for agricultural field machines
Authors: Oksanen Timo , Visala Arto 
Published: April 2009

AbstractIn this article, a coverage path planning problem is discussed in the case of agricultural fields and agricultural machines. Methods and algorithms to solve this problem are developed. These algorithms are applicable to both robots and human‐driven machines. The necessary condition is to cover the whole field, and the goal is to find as efficient a route as possible. As yet, there is no universal algorithm or method capable of solving the problem in all cases. Two new approaches to solve the coverage path planning problem in the case of agricultural fields and agricultural machines are presented for consideration. Both of them are greedy algorithms. In the first algorithm the view is from on top of the field, and the goal is to split a single field plot into subfields that are simple to drive or operate. This algorithm utilizes a trapezoidal decomposition algorithm, and a search is developed of the best driving direction and selection of subfields. This article also presents other practical aspects that are taken into account, such as underdrainage and laying headlands. The second algorithm is also an incremental algorithm, but the path is planned on the basis of the machine's current state and the search is on the next swath instead of the next subfield. There are advantages and disadvantages with both algorithms, neither of them solving the problem of coverage path planning problem optimally. Nevertheless, the developed algorithms are remarkable steps toward finding a way to solve the coverage path planning problem with nonomnidirectional vehicles and taking into consideration agricultural aspects. © 2009 Wiley Periodicals, Inc.
Bayesian pharmacovigilance signal detection methods revisited in a multiple comparison setting
Authors: Ahmed Ismaïl , Haramburu Françoise , Fourrier‐Réglat Annie , Thiessard Frantz , Kreft‐Jais Carmen , Miremont‐Salamé Ghada , Bégaud Bernard , Tubert‐Bitter Pascale 
Published: April 2009

AbstractPharmacovigilance spontaneous reporting systems are primarily devoted to early detection of the adverse reactions of marketed drugs. They maintain large spontaneous reporting databases (SRD) for which several automatic signalling methods have been developed. A common limitation of these methods lies in the fact that they do not provide an auto‐evaluation of the generated signals so that thresholds of alerts are arbitrarily chosen. In this paper, we propose to revisit the Gamma Poisson Shrinkage (GPS) model and the Bayesian Confidence Propagation Neural Network (BCPNN) model in the Bayesian general decision framework. This results in a new signal ranking procedure based on the posterior probability of null hypothesis of interest and makes it possible to derive with a non‐mixture modelling approach Bayesian estimators of the false discovery rate (FDR), false negative rate, sensitivity and specificity. An original data generation process that can be suited to the features of the SRD under scrutiny is proposed and applied to the French SRD to perform a large simulation study. Results indicate better performances according to the FDR for the proposed ranking procedure in comparison with the current ones for the GPS model. They also reveal identical performances according to the four operating characteristics for the proposed ranking procedure with the BCPNN and GPS models but better estimates when using the GPS model. Finally, the proposed procedure is applied to the French data. Copyright © 2009 John Wiley & Sons, Ltd.
Electrospray Encapsulation of Hydrophilic and Hydrophobic Drugs in Poly(L‐lactic acid) Nanoparticles
Authors: Valo Hanna , Peltonen Leena , Vehviläinen Satu , Karjalainen Milja , Kostiainen Risto , Laaksonen Timo , Hirvonen Jouni 
Published: April 2009

AbstractAn electrospray method is developed for preparation of beclomethasone‐dipropionate‐ and salbutamol‐sulfate‐loaded biodegradable poly(L‐lactic acid) nanoparticles. Different set‐up parameters for electrospraying are examined on particle size, and preparation conditions are optimized for producing spherical‐drug‐loaded nanoscale particles by controllable processing parameters. Polylactide (PLA)–drug nanoparticles with average diameters of around 200 nm are achieved in a stable cone‐jet mode with a flow rate of 4 µL min−1, polymer concentration of 1%, and ammonium hydroxide content of 0.05%. Morphology and size of the drug–polymer nanoparticles are analyzed by scanning electron microscopy and transmission electron microscopy. Changes in the crystallinity of the PLA polymer and the model drugs are detected by X‐ray powder diffraction, and the absence of molecular interactions are confirmed by thermal analyses. The results indicate clearly that electrospraying is a potential method for producing polymeric nanoparticles and for encapsulating both hydrophilic and hydrophobic drugs efficiently into the nanoparticles.
Designing Nanogadgetry for Nanoelectronic Devices with Nitrogen‐Doped Capped Carbon Nanotubes
Authors: Lee Sang Uck , Belosludov Rodion V. , Mizuseki Hiroshi , Kawazoe Yoshiyuki 
Published: April 2009

AbstractA systematic analysis of electron transport characteristics for 1D heterojunctions with two nitrogen‐doped (N‐doped) capped carbon nanotubes (CNTs) facing one another at different conformations is presented considering the chirality of CNTs (armchair(5,5) and zigzag(9,0)) and spatial arrangement of N‐dopants. The results show that the modification of the molecular orbitals by the N‐dopants generates a conducting channel in the designed CNT junctions, inducing a negative differential resistance (NDR) behavior, which is a characteristic feature of the Esaki‐like diode, that is, tunneling diode. The NDR behavior significantly depends on the N‐doping site and the facing conformations of the N‐doped capped CNT junctions. Furthermore, a clear interpretation is presented for the NDR behavior by a rigid shift model of the HOMO‐ and LUMO‐filtered energy levels in the left and right electrodes under the applied biases. These results give an insight into the design and implementation of various electronic logic functions based on CNTs for applications in the field of nanoelectronics.
Photoconductivity of Bulk‐Film‐Based Graphene Sheets
Authors: Lv Xin , Huang Yi , Liu Zhibo , Tian Jianguo , Wang Yan , Ma Yanfeng , Liang Jiajie , Fu Shipeng , Wan Xiangjian , Chen Yongsheng 
Published: April 2009

AbstractTime‐resolved photoconductivity measurements are carried out on graphene films prepared by using soluble graphene oxide. High photocurrent generation efficiency is observed for these graphene‐based films, and the relationships between their photoconductivity and different preparation methods, incident light intensity, external electric field, and photon energies are investigated. Higher photoconductivity is observed with higher photon energy at same incident light intensity. By fitting the experimental data to the Onsager model, the primary quantum yields for charge separation to generate bound electron–hole pairs and the initial ion‐pair thermalization separation distance are calculated.
DNER, an Epigenetically Modulated Gene, Regulates Glioblastoma-Derived Neurosphere Cell Differentiation and Tumor Propagation
Authors: Sun Peng , Xia Shuli , Lal Bachchu , Eberhart Charles G. , Quinones-Hinojosa Alfredo , Maciaczyk Jarek , Matsui William , DiMeco Francesco , Piccirillo Sara M. , Vescovi Angelo L. , Laterra John 
Published: April 2009

Abstract
Neurospheres derived from glioblastoma (GBM) and other solid malignancies contain neoplastic stem-like cells that efficiently propagate tumor growth and resist cytotoxic therapeutics. The primary objective of this study was to use histone-modifying agents to elucidate mechanisms by which the phenotype and tumor-promoting capacity of GBM-derived neoplastic stem-like cells are regulated. Using established GBM-derived neurosphere lines and low passage primary GBM-derived neurospheres, we show that histone deacetylase (HDAC) inhibitors inhibit growth, induce differentiation, and induce apoptosis of neoplastic neurosphere cells. A specific gene product induced by HDAC inhibition, Delta/Notch-like epidermal growth factor-related receptor (DNER), inhibited the growth of GBM-derived neurospheres, induced their differentiation in vivo and in vitro, and inhibited their engraftment and growth as tumor xenografts. The differentiating and tumor suppressive effects of DNER, a noncanonical Notch ligand, contrast with the previously established tumor-promoting effects of canonical Notch signaling in brain cancer stem-like cells. Our findings are the first to implicate noncanonical Notch signaling in the regulation of neoplastic stem-like cells and suggest novel neoplastic stem cell targeting treatment strategies for GBM and potentially other solid malignancies.
Disclosure of potential conflicts of interest is found at the end of this article.
HOXA3 Modulates Injury-Induced Mobilization and Recruitment of Bone Marrow-Derived Cells
Authors: Mace Kimberly A. , Restivo Terry E. , Rinn John L. , Paquet Agnes C. , Chang Howard Y. , Young David M. , Boudreau Nancy J. 
Published: April 2009

AbstractThe regulated recruitment and differentiation of multipotent bone marrow-derived cells (BMDCs) to sites of injury are critical for efficient wound healing. Previously we demonstrated that sustained expression of HOXA3 both accelerated wound healing and promoted angiogenesis in diabetic mice. In this study, we have used green fluorescent protein-positive bone marrow chimeras to investigate the effect of HOXA3 expression on recruitment of BMDCs to wounds. We hypothesized that the enhanced neovascularization induced by HOXA3 is due to enhanced mobilization, recruitment, and/or differentiation of BMDCs. Here we show that diabetic mice treated with HOXA3 displayed a significant increase in both mobilization and recruitment of endothelial progenitor cells compared with control mice. Importantly, we also found that HOXA3-treated mice had significantly fewer inflammatory cells recruited to the wound compared with control mice. Microarray analyses of HOXA3-treated wounds revealed that indeed HOXA3 locally increased expression of genes that selectively promote stem/progenitor cell mobilization and recruitment while also suppressing expression of numerous members of the proinflammatory nuclear factor κB pathway, including myeloid differentiation primary response gene 88 and toll-interacting protein. Thus HOXA3 accelerates wound repair by mobilizing endothelial progenitor cells and attenuating the excessive inflammatory response of chronic wounds.Disclosure of potential conflicts of interest is found at the end of this article.
Stem Cell Therapy Restores Transparency to Defective Murine Corneas
Authors: Du Yiqin , Carlson Eric C. , Funderburgh Martha L. , Birk David E. , Pearlman Eric , Guo Naxin , Kao Winston W.-Y. , Funderburgh James L. 
Published: April 2009

Abstract
Corneal scarring from trauma and inflammation disrupts vision for millions worldwide, but corneal transplantation, the primary therapy for corneal blindness, is unavailable to many affected individuals. In this study, stem cells isolated from adult human corneal stroma were examined for the ability to correct stromal opacity in a murine model by direct injection of cells into the corneal stroma. In wild-type mice, injected human stem cells remained viable for months without fusing with host cells or eliciting an immune T-cell response. Human corneal-specific extracellular matrix, including the proteoglycans lumican and keratocan, accumulated in the treated corneas. Lumican-null mice have corneal opacity similar to that of scar tissue as a result of disruption of stromal collagen organization. After injection with human stromal stem cells, stromal thickness and collagen fibril defects in these mice were restored to that of normal mice. Corneal transparency in the treated mice was indistinguishable from that of wild-type mice. These results support the immune privilege of adult stem cells and the ability of stem cell therapy to regenerate tissue in a manner analogous to organogenesis and clearly different from that of normal wound healing. The results suggest that cell-based therapy can be an effective approach to treatment of human corneal blindness.
Disclosure of potential conflicts of interest is found at the end of this article.
Differentiation of a Highly Tumorigenic Basal Cell Compartment in Urothelial Carcinoma
Authors: He Xiaobing , Marchionni Luigi , Hansel Donna E. , Yu Wayne , Sood Akshay , Yang Jie , Parmigiani Giovanni , Matsui William , Berman David M. 
Published: April 2009

AbstractHighly tumorigenic cancer cell (HTC) populations have been identified for a variety of solid tumors and assigned stem cell properties. Strategies for identifying HTCs in solid tumors have been primarily empirical rather than rational, particularly in epithelial tumors, which are responsible for 80% of cancer deaths. We report evidence for a spatially restricted bladder epithelial (urothelial) differentiation program in primary urothelial cancers (UCs) and in UC xenografts. We identified a highly tumorigenic UC cell compartment that resembles benign urothelial stem cells (basal cells), co-expresses the 67-kDa laminin receptor and the basal cell-specific cytokeratin CK17, and lacks the carcinoembryonic antigen family member CEACAM6 (CD66c). This multipotent compartment resides at the tumor-stroma interface, is easily identified on histologic sections, and possesses most, if not all, of the engraftable tumor-forming ability in the parental xenograft. We analyzed differential expression of genes and pathways in basal-like cells versus more differentiated cells. Among these, we found significant enrichment of pathways comprising “hallmarks” of cancer, and pharmacologically targetable signaling pathways, including Janus kinase-signal transducer and activator of transcription, Notch, focal adhesion, mammalian target of rapamycin, epidermal growth factor receptor (erythroblastic leukemia viral oncogene homolog [ErbB]), and wingless-type MMTV integration site family (Wnt). The basal/HTC gene expression signature was essentially invisible within the context of nontumorigenic cell gene expression and overlapped significantly with genes driving progression and death in primary human UC. The spatially restricted epithelial differentiation program described here represents a conceptual advance in understanding cellular heterogeneity of carcinomas and identifies basal-like HTCs as attractive targets for cancer therapy.Disclosure of potential conflicts of interest is found at the end of this article.