bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ab initio investigation of the LiNbO3 (0001) surface
Authors: Sanna Simone , Gavrilenko Alexander V. , Schmidt Wolf Gero 
Published: December 2009

AbstractThe polar surfaces of ferroelectric LiNbO3 have been investigated by an ab initio thermodynamical approach. Basing on density functional theory total energy calculations, we discuss the relative stability of a series of candidate surface structures with varying stoichiometry and surface reconstruction in dependence on the chemical environment. We determine the equilibrium geometry for the positively and negatively polarised surfaces and then discuss the influence of different stabilising mechanisms on the preferred terminations. Positive and negative surfaces are found to have different structure, stoichiometry and ionisation energy. The positive surface is found to contain more oxygen than the negative surface at similar conditions. Different stabilisation mechanisms like stoichiometry modification and reconstruction contribute to stabilise the polar surfaces (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inhibition of hepatoma 22 tumor by Liquiritigenin
Authors: Zhou Ming , Higo Haruo , Cai Yunqing 
Published: December 2009

AbstractThe purpose of this study was to evaluate the in vivo antitumor effects of liquiritigenin (LQ) on H22 Hepatocarcinoma. After mice were administrated liquiritigenin (10, 20 and 40 mg/kg) intragastrically for 15 days, tumor volume, indices of thymus and spleen, MDA level in serum, optical microscopy, electron microscopy were determined. We have found that LQ had inhibitory effects on transplanted tumors and that the middle dose of LQ was more effective than the others. All LQ groups could increase thymus weight but it had no obvious effect on the spleen. MDA content decreased with LQ treatment but there wasn't a significant difference. In the group treated with LQ, we observed that the nuclei changed markedly and had ultrastructural morphological changes to apoptosis. The study supports that LQ significantly inhibits the growth of H22 in vivo, and might be a promising antihepatoma agent. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of Athamanta turbith fruit essential oils on CCl4‐induced hepatic failure in mice and their antioxidant properties
Authors: Ana Tomić , Biljana Božin , Isidora Samojlik , Marina Milenković , Neda Mimica‐Dukić , Silvana Petrović 
Published: November 2009

AbstractThe effects of essential oils isolated from mature fruits of Athamanta turbith ssp. hungarica (Borbás) Tutin and A. turbith ssp. haynaldii (Borbás & Uechtr.) Tutin (Umbelliferae) on some liver biochemical parameters in mice intoxicated with carbon tetrachloride were investigated. Pretreatment with both essential oils extenuated the effects caused by carbon tetrachloride. In order to investigate in vitro antioxidant properties of the oils, three methods were applied: scavenging of both 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and OH radicals, as well as a test of inhibition of Fe2+/ascorbic‐induced lipid peroxidation. Investigated essential oils exhibited modest antioxidant capacity. Therefore, their influence on biochemical parameters in intoxicated animals might be linked to the inhibition of enzymes (cytochrome P450 2E1) involved in metabolic activation of halomethanes. Copyright © 2009 John Wiley & Sons, Ltd.
Boswellia frereana(frankincense) suppresses cytokine‐induced matrix metalloproteinase expression and production of pro‐inflammatory molecules in articular cartilage
Authors: Blain Emma J. , Ali Ahmed Y. , Duance Victor C. 
Published: November 2009

AbstractThe aim of this study was to assess the anti‐inflammatory efficacy ofBoswellia frereanaextracts in anin vitromodel of cartilage degeneration and determine its potential as a therapy for treating osteoarthritis. Cartilage degradation was inducedin vitroby treating explants with 5 ng/ml interleukin1α (IL‐1α) and 10 ng/ml oncostatin M (OSM) over a 28‐day period, in the presence or absence of 100 μg/mlB. frereana. Treatment of IL‐1α/OSM stimulated cartilage explants withB. frereanainhibited the breakdown of the collagenous matrix.B. frereanareduced MMP9 and MMP13 mRNA levels, inhibited MMP9 expression and activation, and significantly reduced the production of nitrite (stable end product of nitric oxide), prostaglandin E2 and cycloxygenase‐2.Epi‐lupeol was identified as the principal constituent ofB. frereana.This is the first report on the novel anti‐inflammatory properties ofBoswellia frereanain anin vitromodel of cartilage degradation. We have demonstrated thatB. frereanaprevents collagen degradation, and inhibits the production of pro‐inflammatory mediators and MMPs. Due to its efficacy we propose thatB. frereanashould be examined further as a potential therapeutic agent for treating inflammatory symptoms associated with arthritis. Copyright © 2009 John Wiley & Sons, Ltd.
Water quality in the southern Tibetan Plateau: chemical evaluation of the Yarlung Tsangpo (Brahmaputra)
Authors: Huang X. , Sillanpää M. , Gjessing E. T. , Peräniemi S. , Vogt R. D. 
Published: December 2009

AbstractYarlung Tsangpo (Brahmaputra) is the largest river system draining the northern slopes of the Himalayan ranges on the southern Tibetan Plateau. It remains one of only two large non‐regulated rivers in China. In this paper the chemical composition of Yarlung Tsangpo and its major tributaries (Raga Tsangpo, Nyangchu and Lhasa River) are studied. Water samples (n = 55) were collected and measured for major ions, trace elements and nutrients in order to: (1) define the present chemical quality of this water course; (2) address possible mechanisms governing the water chemical compositions, and (3) identify potential sources for contaminants. Multivariable analysis shows that geology and climate are the major explanatory variables for the spatial variation in water chemistry in this river system. In general, water chemistry is mainly controlled by carbonate weathering, with Ca2+ and HCO being the dominant ions. In addition, runoff from brackish/saline lakes and geothermal waters, enriched in Na+, Cl−, SO, Mg2+ and Li, are major contributors of elevated concentrations of these solutes in the headwater regions resulting in a relatively high loading of total dissolved solids (TDS, 146–397 mg L−1). Levels of most heavy metals and total dissolved nutrients were generally found to be low. However, elevated As concentration (avg. 95 μg L−1) in the headwaters and additions from untreated wastewater were evident at some locations. Copyright © 2009 John Wiley & Sons, Ltd.
The influence of substrate surface roughness on microstrip transmission line loss using conventional analyses and length‐scale fractal analysis
Authors: Vincent Tracey , Powers Brendan , Bar‐On Isa 
Published: December 2009

AbstractTwo components of conductor topography can impact conductor loss for signals in the GHz frequency range: conductor–ceramic interface roughness and conductor edge angle. This study is an experimental investigation of the influence of these conductor topographies on conductor loss in microstrip circuits produced by thick‐film technology. The aluminum nitride ceramic substrates have different surface roughnesses due to different surface finish processes. The substrate surfaces were characterized using conventional and length‐scale fractal analysis. The conductor–ceramic interface was measured with a contact profilometer. The conductor edge angle and conductor edge profile were measured optically. It was found that there is a direct correlation between conductor loss and conductor edge angle, whereas there is an inverse correlation between loss and substrate roughness or relative length of the conductor–ceramic interface. This is the opposite result to the conventional expectation of surface roughness effects on conductor loss. There is also a negative correlation between conductor edge angle and surface roughness or relative length. The loss behavior can be explained by the interaction of the conductor paste with the surfaces during processing. The paste tends to spread more on the smoother surfaces, and thus creates an elongated edge of diminishing cross‐section and a small edge angle. This leads to greater conductor loss. Copyright © 2009 John Wiley & Sons, Ltd.
Theoretical Efficiency of Nanostructured Graphene‐Based Photovoltaics
Authors: Yong Virginia , Tour James M. 
Published: November 2009

AbstractGraphene‐based organic photovoltaics (OPVs) have the potential for single‐cell efficiencies exceeding 12% (and 24% in a stacked structure). A generalized equivalent circuit for OPVs is proposed and the validation of the proposed models is verified by simulation. The simulated short‐circuit photocurrent density (computed using the simulated incident photon flux density and quantum yield), simulated current–voltage curve, and simulated 3D surface and 2D contour plots of solar‐power‐conversion efficiency versus carrier mobility and photoactive layer thickness are in good agreement with experimental observations. The results suggest that graphene renders a credible material for the construction of next‐generation flexible solar‐energy‐conversion devices that are low‐cost, high‐efficiency, thermally stable, environmentally friendly, and lightweight.
Prenatal diagnosis of congenital agenesis of the fetal portal venous system
Authors: Achiron R. , Gindes L. , Kivilevitch Z. , Kuint J. , Kidron D. , Boyanover Y. , Yakobson J. , Heggesh J. 
Published: December 2009

AbstractObjectiveTo describe the prenatal diagnosis and review our experience of fetal congenital agenesis of the portal venous system (CAPVS) and to review the current literature on this poorly documented vascular malformation.MethodsThis was a retrospective survey covering the 12‐year period between 1996 and 2008. The database of a single, large, ultrasonographic tertiary academic referral center in Israel was analyzed and cases with a prenatal diagnosis of CAPVS were identified. All fetuses underwent detailed biometric and structural ultrasound examinations and a precise anatomical description of the fetal umbilical, portal and hepatic venous system was noted, as well as the presence of aberrant vessels, shunt location and the presence or absence of the DV. Results of fetal echocardiography, karyotyping and toxoplasma, rubella, cytomegalovirus and herpes evaluations were determined. Medical records were evaluated. Diagnosis was confirmed by pathology, postmortem venography or neonatal ultrasound or venography. Liveborns were examined by a certified neonatologist and long‐term follow‐up from pediatric gastroenterology units was determined.ResultsNine cases with CAPVS were studied. In all cases an aberrant umbilical–portal vein was the primary indication for detailed portal system evaluation. Five fetuses demonstrated total CAPVS (Type I) and four showed partial agenesis of the portal vein (Type II). Among the five Type I fetuses, there was a shunt from the umbilical vein to the inferior vena cava in three (60%), to the right atrium in one and to the coronary sinus in one. In this group, in only one case could we delineate a common confluence between the splenic vein and the superior mesenteric vein shunting to the inferior vena cava. In four cases termination of pregnancy was performed due to additional findings: one case with hydrothorax, ascites and mitral atresia, one with cleft lip/palate and one with trisomy 21. One case had no additional anomalies, but the parents elected to terminate the pregnancy. All four of the Type II fetuses had a portosystemic shunt: in two cases to the right atrium, in one to the iliac vein and in one to the right hepatic vein. In three, the shunt resolved spontaneously. In only one case was abnormal liver function present over a follow‐up period of 2–10 years.ConclusionCAPVS can be detected prenatally. An abnormal course of the umbilical vein necessitates prompt sonographic evaluation of the umbilical–portal venous system and meticulous investigation for additional anomalies. Complete CAPVS may be associated with remote clinical consequences of which the parents should be informed. Partial CAPVS has a favorable prognosis. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Doppler indices of the middle cerebral artery in fetuses with cardiac defects theoretically associated with impaired cerebral oxygen delivery in utero: is there a brain‐sparing effect?
Authors: Berg C. , Gembruch O. , Gembruch U. , Geipel A. 
Published: December 2009

AbstractObjectivesTo assess changes in the Doppler flow profiles of the middle cerebral artery in fetuses with cardiac defects theoretically associated with impaired cerebral oxygen delivery in utero.MethodsZ‐scores were calculated for pulsatility and resistance indices (PI and RI, respectively) of the middle cerebral artery (MCA) and the cerebroplacental ratio (CPR) between 19 and 41 weeks' gestation, and for head circumference at birth (HC), in 113 fetuses with the following isolated cardiac defects: transposition of the great arteries (TGA; n = 18), hypoplastic left heart (HLH; n = 46), severe aortic stenosis (n = 17), pulmonary atresia (n = 18) and tetralogy of Fallot (TOF; n = 14). Pregnancies with uteroplacental dysfunction (indicated by increased uterine and/or umbilical Doppler indices), growth restriction, extracardiac malformations, chromosomal anomalies as well as multiple pregnancies were excluded to avoid any additional hypoxemic effect as strictly as possible. The results were compared with 1378 normal controls.ResultsFetuses with pulmonary atresia, severe aortic stenosis and TOF had no significant alterations of Doppler parameters or HC at birth. In fetuses with TGA, mean Z‐scores of HC at birth were significantly smaller compared with controls (mean ± SD, −0.73 ± 1.25; P < 0.05), but there was no significant difference in the Doppler parameters. Fetuses with HLH had significantly lower MCA‐PI (−0.57 ± 0.74; P < 0.05), MCA‐RI (−0.73 ± 0.85; P < 0.05), CPR (−1.44 ± 1.05; P < 0.05) and HC (−0.50 ± 1.24; P < 0.05) Z‐scores compared with controls.ConclusionsFetuses with cardiac defects theoretically associated with markedly impaired cerebral oxygen delivery in utero (TGA and HLH) have smaller HCs at birth. However, only fetuses with HLH have cerebrovascular alterations that are detectable by evaluation of the Doppler indices MCA‐PI, MCA‐RI and CPR. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
A simple analytical wind park model considering atmospheric stability
Authors: Emeis S. 
Published: December 2009

AbstractThe analytical top‐down wind park model by Emeis and Frandsen1 is enhanced by consistently making both the downward momentum flux and the momentum loss at the rough surface dependent on atmospheric stability. Specifying the surface roughness underneath the turbines in a wind farm in the model gives the opportunity to investigate principal differences between onshore and offshore wind parks, because the roughness length of the sea surface is two to three orders of magnitude lower than the roughness length of land surfaces. Implications for the necessary distance between single turbines in offshore wind farms and the distance between neighbouring wind parks are computed. It turns out from the model simulations that over smooth surfaces offshore the wind speed reduction at hub height in a wind farm is larger than over rough onshore surfaces given the same density of turbines within the park. Mean wind profiles within the park are also calculated from this model. Offshore wind farms must have a larger distance between each other in order to avoid shadowing effects of the upstream farm. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of variance concepts and computations
Authors: Muller Keith E. 
Published: December 2009

AbstractThe analysis of variance (ANOVA) compares means among three or more groups of observations defined by a categorical variable. Any discussion of ANOVA involves intertwined considerations of (1) scientifically informed study design, (2) computational methods, and (3) statistical theory. Our understanding advances at roughly at the same rate in all three aspects. The earliest ANOVA methods were developed in 1925 and required independent Gaussian observations with common variance. The years 1925–1950 saw the flowering of complex variations for evaluating two or more grouping variables (factors) and the possibility of interaction among factors. An interaction occurs whenever the effect of one factor differs across levels of the other. Requiring equal numbers of observations in each group allowed developing sums‐of‐squares formulas practical for electromechanical calculators. The widespread adoption of digital electronic computers during 1950–1975 stimulated a shift to regression‐based calculations allowing unequal group sizes and the use of multivariate methods. During 1975–2000, statisticians generalized ANOVA based on mixed models to allow missing data. The more general methods require iterative solutions of nonlinear systems of equations. The dominance of the mixed‐model approach creates vulnerabilities to computing and modeling errors in practice. Basic numerical analysis concerns (variable scaling, location shift, and error accumulation) can interact badly with some types of coding dummy variables and covariance model selection. Future directions include automation of access to computation and assumption diagnostics. The proliferation of data with large numbers of variables or observations presents challenges at all three interfaces of scientific modeling, computing, and statistical theory. Copyright © 2009 John Wiley & Sons, Inc.This article is categorized under:

Statistical Models > Linear Models
Statistical Models > Classification Models
Nutritional status of selenium in Alzheimer's disease patients
Authors: Cardoso Bárbara Rita , Ong Thomas Prates , Jacob-Filho Wilson , Jaluul Omar , Freitas Maria Isabel d'Ávila , Cozzolino Silvia M. Franciscato 
Published: December 2009

Studies have shown that various antioxidants are decreased in different age-related degenerative diseases and thus, oxidative stress would have a central role in the pathogenesis of many disorders that involve neuronal degeneration, including Alzheimer's disease (AD). The present study aimed to assess the nutritional status of Se in AD patients and to compare with control subjects with normal cognitive function. The case–control study was carried out on a group of elderly with AD (n 28) and compared with a control group (n 29), both aged between 60 and 89 years. Se intake was evaluated by using a 3-d dietary food record. Se was evaluated in plasma, erythrocytes and nails by using the method of hydride generation atomic absorption spectroscopy. Deficient Se intake was largely observed in the AD group. AD patients showed significantly lower Se levels in plasma, erythrocytes and nails (32·59 μg/l, 43·74 μg/l and 0·302 μg/g) when compared with the control group (50·99 μg/l, 79·16 μg/l and 0·400 μg/g). The results allowed us to suggest that AD has an important relation with Se deficiency.
Improving Loran Coverage with Low Power Transmitters
Authors: Lo Sherman C. , Peterson Benjamin B. , Hardy Tim , Enge Per K. 
Published: December 2009

Enhanced Loran (eLoran) is currently being implemented to provide back up to global navigation satellite systems (GNSS) in many critical and essential applications. In order to accomplish this, eLoran needs to provide a high level of availability throughout its desired coverage area. While the current Loran system is generally capable of accomplishing this, worldwide, there remain a number of known areas where improved coverage is desirable or necessary. One example is in the middle of the continental United States where the transmitter density is not adequate for providing the desired availability for applications such as aviation in some parts. This paper examines the use of lower power, existing assets such as differential GPS (DGPS) and Ground Wave Emergency Network (GWEN) stations to enhance coverage and fill these gaps. Two areas covered by the paper are the feasibility and performance benefits of using the antennas at these sites.Using DGPS, GWEN or other existing low frequency (LF) broadcast towers requires the consideration of several factors. The first is the ability of the transmitting equipment to efficiently broadcast on these antennas, which are significantly shorter than those at a Loran station. Recent tests at the US Coast Guard Loran Support Unit (LSU) demonstrated the performance of a more efficient transmitter. This technology allows for the effective use of smaller antennas at lower power levels. Second is the ability to broadcast a navigation signal that is compatible with the Loran system and the potential DPGS broadcast (when using a DGPS antenna). The paper examines some possibilities for navigation signals. The goal is to develop a suitable low power signal that enhances navigation and is feasible for the transmission system.The second part of the paper examines the benefits of using these stations. The benefits depend on the location of the stations and the ability seamlessly to integrate them within the existing Loran infrastructure. Analysis of these factors is presented and the coverage benefits are examined.
Influenza-attributable mortality in Australians aged more than 50 years: a comparison of different modelling approaches
Authors: NEWALL A. T. , VIBOUD C. , WOOD J. G. 
Published: November 2009

SUMMARYThis study aimed to compare systematically approaches to estimating influenza-attributable mortality in older Australians. Using monthly age-specific death data together with viral surveillance counts for influenza and respiratory syncytial virus, we explored two of the most frequently used methods of estimating excess influenza-attributable disease: Poisson and Serfling regression models. These approaches produced consistent age and temporal patterns in estimates of influenza-attributable mortality in older Australians but some variation in the magnitude of the disease burden. Of Australians aged >50 years, average annual estimated influenza-attributable deaths (all cause) ranged from 2314 to 3457 for the Serfling and Poisson regression models, respectively. The excess influenza-attributable disease burden was substantial under all approaches.
Gorse seed bank variability in maritime pine stands
Authors: Gonzalez Maya , Mathieu Alexis , Augusto Laurent , Gire Céline , Bakker Mark R. , Budynek Anne 
Published: December 2009

AbstractEuropean gorse (Ulex europaeusL.) is a spiny shrub that grows spontaneously in the understorey of forests and heathlands in western Europe. Gorse is a pioneer species and forms large seed banks that can persist for a long time while buried deeply in the soil. Although many studies have been conducted on gorse seed banks in invasive contexts and in scrubland ecosystems, few data are available on forests in a native context. The aim of the present study was thus to report on the variability of seed-bank density in ‘critical’ stages in the forest management of pine stands (five stands) in south-western France. We examined variations in the number of gorse seeds as a function of soil depth but also of the presence and abundance of adult gorse in the understorey. Seed-bank density did not show a clear decrease in seed number with pine stand age, principally because gorse also appears to be able to establish itself in mature pine stands, probably thanks to local disturbances. In the pine stands in our study, the presence and abundance of seeds in the soil appeared to depend mostly on the presence of adult gorse as seeders in the understorey. Finally, we observed that, contrary to what has generally been found in scrubland ecosystems, most gorse seeds were located in the 5–10 cm soil layer rather than in the 0–5 cm soil layer. This depletion of the first 5 cm may be linked to seed germination that was not compensated for by the production of new seeds.