bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent progress of high efficiency white LEDs
Authors: Narukawa Yukio , Narita Junya , Sakamoto Takahiko , Yamada Takao , Narimatsu Hiroki , Sano Masahiko , Mukai Takashi 
Published: May 2007

AbstractWe fabricated three types of white light emitting diodes (LEDs). The first is the white LED, which has a high general color rendering index (Ra) of 97 and CRI‐No. 9 of 96. The CRI‐No. 9 denotes the color reproduction in the red region. These values are higher than those of a tri‐phosphor fluorescent lamp (Ra = 85 and CRI‐No. 9 = 8). The second is the high efficiency white LED fabricated from the small‐size high efficiency blue LED chip. The output power (Po), the external quantum efficiency (ηex) and wall‐plug efficiency (WPE) of the small‐size blue LED were 35.0 mW, 63.3% and 56.3%, respectively, at a forward‐bias current of 20 mA. The luminous flux (Φ), luminous efficiency (ηL) and WPE of the second white LED are 8.6 lm, 138 lm/W and 41.7%, respectively. The luminous efficiency is 1.5 times greater than that of a tri‐phosphor fluorescent lamp (90 lm/W). The third is the high power white LED fabricated from the larger‐size blue LED chip. Po, ηex and W.P.E. are 458 mW, 47.2% and 39.7%, respectively, at 350 mA. Φ, ηL and WPE of the third white LED are 106 lm, 91.7 lm/W and 27.7% at 350 mA, respectively. Moreover, Φ of 247 lm and 402 lm at 1 A and 2 A are obtained, respectively. Φ at 2 A is equivalent to the total flux of a 30 W incandescent lamp. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomic study of molecular wires composed of thiophene oligomers
Authors: Bai P. , Li E. P. , Ong E. A. , Collier P. , Loh K. P. 
Published: May 2007

AbstractIn this paper, we study the electron conductance of thiophene oligomers based molecular wires through atomic structures using the first principles method based on density functional theory and nonequilibrium Green's function. The molecular wires are built by sandwiching various thiophene oligomers between two metal electrodes via terminal groups at atomic levels. The effects of alkyl substituents on the thiophene oligomers are modelled by varying inter‐ring angles of the oligomers. Thiophene dimers, tetramers and hexamers are used to studied thiophene size effects. The projected orbitals, energy gaps, transmission functions and current–voltage characteristics of the molecular wires are calculated and analyzed. Results show that the molecular wires with the planar structures of thiophene oligomers have larger electron transmission functions, hence better electronic conductance than those with twist structures. The conductance of molecular wires decreases when the chain length of the thiophene oligomer increases. The results can provide guidance for design of thiophene molecular electronic wires and other devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Metabolite identification by data‐dependent accurate mass spectrometric analysis at resolving power of 60 000 in external calibration mode using an LTQ/Orbitrap
Authors: Lim Heng‐Keang , Chen Jie , Sensenhauser Carlo , Cook Kevin , Subrahmanyam Vangala 
Published: May 2007

AbstractPerformance evaluation of accurate mass measurement by the LTQ/Orbitrap, at a resolving power of 60 000 and in external calibration mode, indicated that the Orbitrap is capable of providing high mass accuracy of <2 ppm for over 24 h post‐calibration. This, together with limited trade‐off between sensitivity and resolving power plus a wide dynamic range for mass accuracy, suggested that the LTQ/Orbitrap is an ideal analytical tool for structural elucidation of metabolites. The application of the LTQ/Orbitrap to identification of human liver microsomal metabolites of carvedilol was evaluated, using parent mass list triggered data‐dependent multiple‐stage accurate mass analysis, at a resolving power of 60 000 in external calibration mode. A metabolite identification workflow was developed to utilize chemical formulas from high‐resolution accurate mass measurements to confirm structures of product ions of a drug proposed by Mass Frontier, illustrated by identification of structures used to establish lineage of product ions of carvedilol, which later served as a template for identification of its metabolites. A total of 58in vitrometabolites of carvedilol were detected using 5‐ppm mass tolerance filters for theoreticalm/zof protonated molecules of predicted metabolites in addition to product ions and neutral mass losses diagnostic of carvedilol. The chemical formulas with unsaturation numbers calculated from the accuratem/zof precursor and product ions can be used to assign, with a high degree of confidence, the structures of metabolites and the sites of metabolism. The mass accuracies obtained for all full scan MS and MSnspectra were <2 ppm. The majority of the metabolites identified agreed with those previously reported except for those that have not been reported before. For example, several glutathione conjugates of carvedilol were reported for the first time, which may explain the reported hepatotoxicity during clinical trials and recent clinical use. Copyright © 2007 John Wiley & Sons, Ltd.
Impact of approximating or ignoring within‐study covariances in multivariate meta‐analyses
Authors: Ishak K. Jack , Platt Robert W. , Joseph Lawrence , Hanley James A. 
Published: May 2007

AbstractMultivariate meta‐analyses are used to derive summary estimates of treatment effects for two or more outcomes from a joint model. In addition to treatment effects, these models also quantify the correlations between outcomes across studies. To be fully specified, the model requires an estimate of the covariance or correlations between outcomes observed in each study. These are rarely available in published reports, so that analysts must either approximate
these or ignore correlations between effect estimates from the same studies. We examined the impact of errors in approximating within‐study covariances on the parameters of multivariate models in a simulation study. We found that treatment effect and heterogeneity estimates were not strongly affected by inaccurate approximations, but estimates of the correlation between outcomes were sometimes highly biased. The potential for error is greatest when the covariance between outcomes within‐ and between‐studies are of comparable scale. Copyright © 2007 John Wiley & Sons, Ltd.
A spatial structural equation modelling framework for health count responses
Authors: Congdon Peter , Almog Michael , Curtis Sarah , Ellerman Raymond 
Published: May 2007

AbstractA structural equation model is proposed for the impact on area health referral counts of spatially correlated latent constructs. One type of construct is indicator based and represents the underlying morbidity or health need; such constructs are derived in a normal errors measurement model involving a set of observed socio‐economic indicators. Another set of residual constructs represents particularities of service configuration or spatially correlated risks that cannot be proxied by observed indicators. The structural model relates the referral outcomes to both types of construct in a Poisson regression. While multiple spatial factors based on measured socio‐economic indicators have already been proposed, the extension to include both indicator‐based and residual factors is novel. Further novel features are to represent spatially structured heterogeneity and nonlinearity in the impact of the indicator‐based constructs. A case study considers the modelling of a single indicator‐based morbidity construct (taken to represent a need for care) in 62 New York counties, with responses being psychiatric referrals to ambulatory and hospital care. Copyright © 2007 John Wiley & Sons, Ltd.
Ultrastructural effects of DDT, DDD, and DDE on neural cells of the chicken embryo model
Authors: Bornman M. S. , Pretorius E. , Marx J. , Smit E. , van der Merwe C. F. 
Published: May 2007

AbstractHuman exposure to environmental compounds with estrogenic activity and the potential effects on human health is the subject of ongoing scientific debates. Their potential effects raise concern regarding neurological development after prenatal exposure. Central to this debate is the pesticide 1,1,1‐trichloro‐2,2‐bis(4‐chlorophenyl)ethane (DDT). Although it has apparent low acute toxicity in mammals, DDT has a long residual persistence and laboratory research has indicated that it acts on the CNS by interfering with Na+/K+ pump mechanism of the neuronal membranes, causing disruption in Ca2+ homeostasis. Potentially this may lead to both apoptosis and necrosis. The present study investigates the effects of DDT and two of its metabolites DDD and DDE on the ultramorphology of neural cells, using a previously published chicken embryo model. Results indicate cellular swelling, budding, and increased membrane permeability for all three chemicals, accompanied by karyolysis in the DDE group (typical features of oncosis). These results support the finding of other researchers as well as the concerns of the WHO that DDT and its metabolites may cause neurotoxicity after prenatal exposure. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 328–336, 2007.
Predicting acute copper toxicity to valve closure behavior in the freshwater clam Corbicula fluminea supports the biotic ligand model
Authors: Liao Chung‐Min , Jou Li‐John , Lin Chieh‐Ming , Chiang Kuo‐Chin , Yeh Ching‐Hung , Chou Berry Yun‐Hua 
Published: May 2007

AbstractThe objective of this paper is to employ biotic ligand model (BLM) to link between acute copper (Cu) toxicity and its effect on valve closure behavior of freshwater clam Corbicula fluminea in order to further support for the BLM that potentially offers a rapid and cost‐effective method to conduct the acute toxicity tests for freshwater clam exposed to waterborne Cu. Reanalysis of published experimental data of C. fluminea closure daily rhythm and dose–response profiles based on the laboratory‐acclimated clams showed that a BLM‐based Hill model best described the free Cu2+‐activity‐valve closure response relationships. Our proposed Cu‐BLM‐Corbicula model shows that free ionic form of waterborne Cu binds specifically to a biotic ligand (i.e., clam gills) and impairs normal valve closure behavior, indicating that a fixed‐level of metal accumulation at a biotic ligand is required to elicit specific biological effects. With derived mechanistic‐based Cu‐BLM‐Corbicula model, we show that the site‐specific EC50(t) and valve closure behavior at any integrated time can be well predicted, indicating that our model has the potential to develop a biomonitoring system as a bioassay tool to on‐line measure waterborne Cu levels in aquatic systems. Our results confirm that BLM can be improved to analytically and rigorously describe the bioavailable fraction of metal causing toxicity to valve closure behavior in freshwater C. fluminea. We suggest that the Cu‐BLM‐Corbicula model can be used to assist in developing technically defensible site‐specific water quality criteria and performing ecological risk assessment and to promote more focused and efficient uses of resources in the regulation and control of metals and the protection of the aquatic ecosystems. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 295–307, 2007.
A homogenization result for a parabolic equation with Preisach hysteresis
Authors: Kopfová J. 
Published: May 2007

AbstractIn this paper we consider an initial boundary value parabolic problem [cu + 𝒫[u]]_t ‐ div(a ċ ν u) = f, with Preisach hysteresis 𝒫. The functions c, a, and the density function ψ of the Preisach operator are allowed to depend also on the space variable x. The equation is homogenized by considering a sequence of equations with spatially periodic data cϵ, aϵ, and ψϵ, where the spatial period ϵ converges to 0. Properties of hysteresis operators and the concept of two‐scale convergence are used to show the convergence of the corresponding solutions to the solution of the homogenized problem.
Numerical solutions of 2‐D steady incompressible flow in a driven skewed cavity
Authors: Erturk E. , Dursun B. 
Published: May 2007

AbstractThe benchmark test case for non‐orthogonal grid mesh, the “driven skewed cavity flow”, first introduced by Demirdžić et al. [5] for skew angles of α = 30° and α = 45°, is reintroduced with a more variety of skew angles. The benchmark problem has non‐orthogonal, skewed grid mesh with skew angle (α). The governing 2‐D steady incompressible Navier‐Stokes equations in general curvilinear coordinates are solved for the solution of driven skewed cavity flow with non‐orthogonal grid mesh using a numerical method which is efficient and stable even at extreme skew angles. Highly accurate numerical solutions of the driven skewed cavity flow, solved using a fine grid (512 × 512) mesh, are presented for Reynolds number of 100 and 1000 for skew angles ranging between 15° ⩽ α ⩽ 165°.
Antioxidative and prooxidative effects of quercetin on A549 cells
Authors: Robaszkiewicz Agnieszka , Balcerczyk Aneta , Bartosz Grzegorz 
Published: May 2007

AbstractQuercetin, a common plant polyphenol, has been reported to show both antioxidant and prooxidant properties. We studied the effects of quercetin on A549 cells in in vitro culture. We found that low concentrations of the flavonoid stimulated cell proliferation and increased total antioxidant capacity (TAC) of the cells; while higher concentrations of the flavonoid decreased cell survival and viability, thiol content, TAC and activities of superoxide dismutase, catalase and glutathione S‐transferase. Quercetin decreased production of reactive oxygen species in the cells but produced peroxides in the medium. The cellular effects of quercetin are therefore complex and include both antioxidant effects and induction of oxidative stress due to formation of reactive oxygen species in the extracellular medium.
Sulfation of Nod Factors via nodHPQ Is nodD Independent in Rhizobium tropici CIAT899
Authors: Folch-Mallol Jorge Luis , Manyani Hamid , Marroquí Silvia , Sousa Carolina , Vargas Carmen , Nava Noreide , Colmenero-Flores José Manuel , Quinto Carmen , Megías Manuel 
Published: May 2007

A cosmid from the Rhizobium tropici CIAT899 symbiotic plasmid, containing most of the nodulation genes described in this strain, has been isolated. Although this cosmid does not carry a nodD gene, it confers ability to heterologous Rhizobium spp. to nodulate R. tropici hosts (Phaseolus vulgaris, Macroptilium atropurpureum, and Leucaena leucocephala). The observed phenotype is due to constitutive expression of the nodABCSUIJ operon, which has lost its regulatory region and is expressed from a promoter present in the cloning vector. Thin-layer chromatography (TLC) analysis of the Nod factors produced by this construction shows that it is still capable of synthesizing sulfated compounds, suggesting that the nodHPQ genes are organized as an operon that is transcribed in a nodD-independent manner and is not regulated by flavonoids. Se ha aislado un cósmido del plásmido simbiótico de Rhizobium tropici CIAT899 que contiene la mayoría de los genes de nodulación descrito para esta estirpe, menos el gen regulador nodD. La introducción de este cósmido en una estirpe curada del plásmido simbiótico de R. tropici CIAT899 permite la nodulación en las plantas ensayadas (Phaseolus vulgaris, Macroptilium atropurpureum, y Leucaena leucocephala). El fenotipo observado se debe a la expresión constitutiva del operón nodABCSUIJ bajo el promotor del gen de resistencia a la kanamicina, que lleva el vector donde se ha clonado el fragmento de ADN. Análisis por cromatografia de capa fina demuestran que esta construcción es capaz de sulfatar el extremo reductor del factor Nod. Estas evidencias sugieren que los genes nodHPQ constituyen un operón, y que su expresión es independiente del gen regulador nodD.
First Report of Root Rot of Bean and Soybean Caused by Rhizoctonia zeae in Turkey
Authors: Erper I. , Karaca G. , Özkoç I. 
Published: May 2007

To determine the species of Rhizoctonia on bean and soybean plants grown in Samsun (Turkey), field surveys were performed at 104 locations during 2001 and 2002. Rhizoctonia spp. were obtained from isolations from the necrotic lesions on the hypocotyl and rhizosphere soils. Species were identified according to Ogoshi (3) on the basis of hyphal and colony morphology and anastomosis reaction with known tester isolates (provided by M. Hyakumachi, Gifu University, Japan). Fifty Rhizoctonia spp. isolates obtained from these locations were identified as Rhizoctonia zeae (teleomorph Waitea circinata var. zeae). Nine of the 27 bean isolates and 8 of the 23 soybean isolates were recovered from plant tissues. These isolates had optimum temperature (32°C) for growth. Colonies were orange when young, becoming salmon colored with age. Sclerotia formed both on the agar surface or submerged in the medium. Superficial sclerotia were more uniform and nearly spherical, mostly 0.2 to 0.5 mm in diameter, and they were first orange and then turned brown. Pathogenicity was tested with three R. zeae isolates grown on sterile oat seeds at 25°C for 10 days. Bean and soybean seedlings grown in 1-liter plastic pots containing sterile potting mix (field soil/composted manure/sand 2:2:1 [v/v]) at true-leaf stage were inoculated by placing five infested oat seeds adjacent to the roots. Sterile oat seeds were used for controls. After 3 to 4 weeks of incubation at 17 to 25°C in a glasshouse, roots of the plants were cleaned with tap water and evaluated for disease severity. Four replicate pots were used for each isolate/plant combination. All isolates produced superficial brown lesions on roots and hypocotyls similar to those observed on plants used for isolations and root growth declined. R. zeae was reisolated from the lesions on all bean and soybean plants used for the pathogenicity test. While R. zeae was previously reported from Johnsongrass roots (1) and corn kernels (2), to our knowledge, this is the first report of R. zeae isolated from bean and soybean plants and rhizosphere soils in Turkey. References: (1) E. Demirci, and C. Eken. Plant Dis. 83:200, 1999. (2) E. Demirci and S. Kordali. Plant Dis. 83:879, 1999. (3) A. Ogoshi. Rev. Plant. Prot. Res. 8:93, 1975.
First Report of Botryosphaeria ribis as a Branch Dieback Pathogen of Olive Trees in Spain
Authors: Romero M. A. , Sánchez M. E. , Trapero A. 
Published: May 2007

Botryosphaeria spp. are known to produce cankers and dieback in several woody hosts. Since 2001, a severe disease resulting in the dieback of branches was observed in olive (Olea europaea) orchards in Andalucía, southern Spain, where the only cultivar affected was Gordal de Sevilla. The affected trees showed abundant dead twigs, and wilted leaves remained attached. These symptoms were similar to those caused by Resseliella oleisuga, a bark borer insect common in the region. Closer inspection showed no evidence of insects, but revealed reddish brown bark lesions that girdled the affected branches. When the outer bark was removed, the affected tissue appeared dark brown, in contrast to the yellowish green of healthy inner bark. A Fusicoccum sp. was consistently isolated from the necrotic bark. Conidia produced in black pycnidia were hyaline, aseptate, fusoid, with a truncate base averaging 19.9 × 6.7 μm, becoming pale brown with all cells the same color, and developing one or two septa when germinated. These characteristics conform to Fusicoccum ribis (1), the anamorph of B. ribis. Pathogenicity of two isolates from symptomatic branches was determined by stem inoculations of 4-year-old cv. Gordal de Sevilla grafted on wild olive trees growing in plastic pots containing a sand/lime/peat soil mixture. Both isolates were inoculated by three techniques. In the first, 7-mm-diameter agar plugs bearing actively growing mycelium were applied to 7-mm-diameter bark wounds made with a cork borer on the middle point of stems (averaging 10 mm in diameter). In the second technique, the same type of inoculum was applied directly to the bark without any wounding. For the third technique, 100 μl of conidial suspension in water (2 × 105 conidia per ml) was applied to bark wounds. The inoculated stem sections were wrapped in Parafilm to retain moisture. All inoculated and control plants (only sterile agar medium or sterile water added) were kept in a greenhouse and watered as needed. There were three replicate plants per isolate and inoculation technique. After 3 months, all plants inoculated with mycelium applied to wounds showed girdling and apical death with browning and wilting of leaves above the inoculation point. In the treatments where mycelium was applied to unwounded bark or where conidial suspensions were applied to wounds, small bark cankers developed to 56 mm long, but neither girdling nor foliar wilting were observed. No symptoms developed in the control plants. There were no significant differences in pathogenicity between the two F. ribis isolates. F. ribis was recovered from necrotic bark from every inoculated plant. These results demonstrate that B. ribis is pathogenic on cv. Gordal de Sevilla olives, and they indicate that bark wounding favors lesion development but is not needed for infection. Reference: (1) B. Slippers et al. Mycologia 96:83, 2004.
First Report of Rust Caused by Puccinia carthami on Safflower in Oman
Authors: Deadman M. L. , Al Sadi A. M. , Al Jahdhami S. , Aime M. C. 
Published: May 2007

Safflower (Carthamus tinctorius L.) is a minor, but culturally important crop in Oman; the dried flowers produce a pigment used in facial ornamentation. Although Oman is not a commercial producer of safflower, the region is a center of diversity and a source of genetic material for breeding programs. Production of oil from safflower has potential in Oman, where plant growth is prolific. In April 2004, leaf samples showing rust symptoms were collected from Mudhaibi, 100 km south of Muscat. Chestnut brown pustules covered both sides of the leaves, but not the stems, and yielded urediniospores and teliospores typical of the pathogen. Urediniospores were globose, 25 μm in diameter with three germ pores. Two-celled teliospores were chestnut brown, minutely verrucose, with a single, depressed germ pore in each cell. The pathogen was identified as Puccinia carthami Corda (voucher specimen deposited in the U.S. National Fungus Collections, BPI863557; nuclear ribosomal large subunit DNA voucher sequence deposited in GenBank, Accession No. AY787782). On the basis of phylogenetic analyses, the rust from Oman belongs to a complex of closely related Puccinia spp. that infects members of the Cardueae. Elsewhere, in addition to leaf infections, P. carthami causes foot and root disease of safflower (1) with teliospores surviving in the soil and on seed to initiate new infections. Germplasm is now being collected and will be screened for variation in response to rust infection. Reference: (1) M. L. Schuster et al. Phytopathology 42:211, 1952.