bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficacy of the pyrethroid alpha‐cypermethrin against Bactrocera oleae populations from Greece, and improved diagnostic for an iAChE mutation
Authors: Margaritopoulos John T , Skavdis George , Kalogiannis Nikos , Nikou Dimitra , Morou Evangelia , Skouras Panagiotis J , Tsitsipis John A , Vontas John 
Published: April 2008

AbstractBACKGROUND: The most important pest of olive orchards worldwide is the olive fruit fly Bactrocera oleae (Gmelin). Its control in Greece has been based on organophosphates (OPs), but their intense use has led to the development of resistance. A test previously developed to monitor the trait may not be as robust as originally thought. The pyrethroid alpha‐cypermethrin has recently been registered for bait sprays, as an alternative to OPs.RESULTS: The susceptibility of 20 B. oleae populations to alpha‐cypermethrin was examined. Variation was observed in their response, with LD50 ranging from 0.14 to 3.28 ng insect−1 and resistance factors from 2.3 to 54.7. Resistance mechanisms were investigated. Cytochrome P450 monoxygenase activities showed an association with resistance. Sequences in the domain IIS4–IIS6 of the B. oleae para‐type sodium channel were also analysed, but no resistance‐associated mutations were identified. Finally, a novel diagnostic assay able to reliably monitor the frequency of the iAChE G488S resistance mutation was developed.CONCLUSION: This is the first attempt to evaluate the efficacy of alpha‐cypermethrin against B. oleae from Greece. Data showed that it can be used effectively, but also highlighted the importance of continuous monitoring. The IIS4–IIS6 sodium channel region is the default area in which to look for resistance mutations if target‐site resistance to pyrethroids arises. The application of the novel iAChE molecular diagnostic may facilitate the introduction of pyrethroids alongside OPs currently in use. Copyright © 2008 Society of Chemical Industry
Synthesis of full length PB1‐F2 influenza A virus proteins from ‘Spanish flu’ and ‘bird flu’
Authors: Röder René , Bruns Karsten , Sharma Alok , Eissmann André , Hahn Friedrich , Studtrucker Nicole , Fossen Torgils , Wray Victor , Henklein Peter , Schubert Ulrich 
Published: April 2008

AbstractThe proapoptotic influenza A virus PB1‐F2 protein contributes to viral pathogenicity and is present in most human and avian isolates. Previous synthetic protocols have been improved to provide a synthetic full length H1N1 type PB1‐F2 protein that is encoded by the ‘Spanish flu’ isolate and an equivalent protein from an avian host that is representative of a highly pathogenic H5N1 ‘bird flu’ isolate, termed SF2 and BF2, respectively. Full length SF2, different mutants of BF2 and a number of fragments of these peptides have been synthesized by either the standard solid‐phase peptide synthesis method or by native chemical ligation of unprotected N‐ and C‐terminal peptide fragments. For SF2 chemical ligation made use of the histidine and the cysteine residues located in positions 41 and 42 of the native sequence, respectively, to afford a highly efficient synthesis of SF2 compared to the standard SPPS elongation method. By‐product formation at the aspartic acid residue in position 23 was prevented by specific modifications of the SPPS protocol. As the native sequence of BF2 does not contain a cysteine residue two different mutants of BF2 (Y42C) and BF2 (S47C) with appropriate cysteine exchanges were produced. In addition to the full length molecules, fragments of the native sequences were synthesized for comparison of their physical characteristics with those from the H1N1 human isolate A/Puerto Rico/8/34 (H1N1). All peptides were analyzed by mass spectrometry, 1H NMR spectroscopy, and SDS‐PAGE. The protocols allow the synthesis of significant amounts of PB1‐F2 and its related peptides. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Polarization dependent photoluminescence of charged quantum dot molecules
Authors: Stinaff E. A. , Ramanathan Swati , Wijesundara Kushal C. , Garrido Mauricio , Scheibner M. , Bracker A. S. , Gammon D. 
Published: April 2008

AbstractWe present the polarization dependent photoluminescence from coupled InAs quantum dots. We find polarization memory signatures consistent with those reported for single quantum dots. We also observe a continuous change in the polarization memory of the positively charged exciton as it changes charge configuration due to a hole tunnelling as a function of applied bias. This may provide a method for electrical control of the anisotropic exchange interaction which would be useful for spin manipulation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and optical properties of a‐plane AlN and Al rich AlN/AlxGa1–xN quantum wells grown on r‐plane sapphire substrates
Authors: Tahtamouni T. Al , Sedhain A. , Lin J. Y. , Jiang H. X. 
Published: April 2008

AbstractA‐plane AlN epilayers and AlN/Al0.65Ga0.35N quantum wells (QWs) have been grown on r‐plane sapphire substrates by metal organic chemical vapor deposition. The growth surface and high crystalline quality were confirmed by x‐ray diffraction. Photoluminescence (PL) spectroscopy has been employed to probe the optical quality of the grown templates and QWs. The PL emission intensity of a‐plane AlN has been compared with that of c‐plane AlN. It was shown that the surface emission intensity of a‐plane AlN epilayers is compara‐ ble to that of c‐plane AlN. The PL emission properties of a‐ and c‐plane AlN/Al0.65Ga0.35N QWs were studied and compared. It was found that the low temperature PL characteristics of a ‐plane QWs are primarily governed by the quantum size effect, whereas those of c ‐plane QWs are significantly affected by the polarization fields. The PL decay time was found to be only weakly dependent on the well width, Lw, for a ‐plane QWs, whereas a strong dependence of the PL decay time on Lw was observed for c ‐plane QWs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improvement of GaN‐based LED with SiO2 photonic crystal on an ITO film by holographic lithography
Authors: Yen H. H. , Kuo H. C. , Yeh W. Y. 
Published: April 2008

AbstractGaN‐based light‐emitting diode (LED) with SiO2 photonic crystals (PCs) structure made by holographic lithography on an indium‐tin‐oxide (ITO) film was fabricated. The PCs made on SiO2 but an ITO film both improves the light extraction efficiency of the GaN‐based LED and prevents the sheet resistance increasing of the ITO film from the dry etching damage. It was found that the forward voltage at 20 mA of the GaN‐based LED with SiO2 PCs on an ITO film was 1.9% higher than the GaN‐based LED with a planar ITO film only. The output power of GaN‐based LED with SiO2 PCs on an ITO film at 20mA was 17.1%, 26.5% and 125.3% higher than that of the GaN‐based LEDs with the planar SiO2/ITO, planar ITO or Ni/Au surface layers, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN vertical n‐p junctions prepared by Si ion implantation
Authors: Kocan M. , Umana‐Membreno G. A. , Recht F. , Baharin A. , Fichtenbaum N. A. , McCarthy L. , Keller S. , Menozzi R. , Mishra U. K. , Parish G. , Nener B. D. 
Published: April 2008

AbstractWe report on n‐p junctions formed on p/p+ GaN layers by silicon ion‐implantation. Post‐implantation damage removal was performed by annealing at 1260 °C in N2/NH3 ambient. Rectifying behaviour observed in current‐voltage measurements was associated with the n‐p junctions formed by ion‐implantation. In circular devices with a vertical n‐p junction topology, light emission under forward bias conditions was observed as a ring near the periphery of the n‐contact region, confirming the existence of an electrically active n‐p junction. The electrical‐characteristics of the n‐p diodes does not seem to be limited by the quality of the implanted junction but rather by the high spreading resistance of the underlying p+ contact layer, for which activation was incomplete. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sidewall epitaxial lateral overgrowth of nonpolar a‐plane GaN by metalorganic vapor phase epitaxy
Authors: Iida Daisuke , Kawashima Takeshi , Iwaya Motoaki , Kamiyama Satoshi , Amano Hiroshi , Akasaki Isamu 
Published: April 2008

AbstractA major obstacle to achieving high‐performance devices using nonpolar a‐plane and m‐plane GaN is the existence of high‐density threading dislocations and stacking faults. Low‐defect‐density nonpolar plane GaN films were previously grown by sidewall epitaxial overgrowth using metalorganic vapor phase epitaxy [1, 2]. In this study, we control the growth‐rate ratio of Ga‐polar GaN to N‐polar GaN by adjusting the V/III ratio. It is possible to grow GaN only from the N‐face sidewall of grooves by maintaining a high V/III ratio, which reduces the number of coalescence regions on grooves and decreases the threading‐dislocation density and stacking‐fault density. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nitride based nanotransistors as new sources and detectors of THz radiations
Authors: Fatimy A. El , Teppe F. , Boubanga S. , Dyakonova N. , Gil B. , Coquillat D. , Seliuta D. , Valušis G. , Poisson M.‐A. , Morvan E. , Gaquiere Ch. , Theron D. , Cappy A. , Knap W. 
Published: April 2008

AbstractThe plasma waves in gated two‐dimensional electron gas have a linear dispersion law, similar to the sound waves. The transistor channel is acting as a resonator cavity for the plasma waves, which can reach frequencies in the Terahertz (THz) range for a sufficiently short gate length Field Effect Transistors (FETs). THz emission and detection by nanometer III‐V transistors have been recently reported. In this work we report on THz emission and detection by nanometer GaN/AlGaN HEMTs. In particular, we show that specific GaN properties allow to observe THz emission up to room temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport properties in n‐type AlGaN/AlN/GaN‐superlattices
Authors: Hertkorn J. , Brückner P. , Gao C. , Scholz F. , Chuvilin A. , Kaiser U. , Wurstbauer U. , Wegscheider W. 
Published: April 2008

AbstractIn order to improve the lateral conductivity in optoelectronic devices, we have investigated Si‐doped AlGaN/AlN/GaN‐superlattices. As a first step we performed calculations of the band structure of Al‐GaN/AlN/GaN modulation doped multi heterostructures. Based on these results we worked on optimizing the growth of low Al content (xAl ≤ 20%) superlattices by MOVPE. Several tens of abrupt and graded AlGaN/AlN/GaN‐layer pairs could be grown crack‐free on 2 μm thick n‐GaN layers deposited on sapphire substrates with AlN nucleation. By Van‐der‐Pauw Hall measurements, we determined that the lateral conductivity of a 1.5 μm thick superlattice structure is a factor of four higher than in highly n‐doped bulk material with comparable thickness without compromising too much the vertical conductivity as confirmed by two step TLM‐measurements. At 4K we could demonstrate an extremely high effective mobility of 18760 cm2/Vs at n=2×1014 cm–2 (R=1.6Ω/®), a clear verification of our excellent crystal quality. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effects of growth temperature on the crystallinity of GaN in gallium hydride vapor phase epitaxy method
Authors: Yamada Norihide , Imade Mamoru , Kitano Yoshihiro , Kawamura Fumio , Yoshimura Masashi , Kitaoka Yasuo , Sasaki Takatomo , Mori Yusuke 
Published: April 2008

AbstractHigh temperature growth was investigated as a way of improving the crystallinity and surface morphology of the gallium hydride vapor phase epitaxy (GaH‐VPE) crystal growth method. In this method, gallium hydride (GaHx: x=1, 2, 3) is characteristically used as a Ga source to grow GaN crystals. We previously confirmed that the growth rate of GaN increased with GaHx supply and could attain almost the same rate as that of the hydride vapor phase epitaxy (HVPE) method. However, an improvement of the surface morphology and crystallinity of GaN crystals was required. In the present study, the dependence of growth temperature on the crystallinity and the surface morphology of grown crystals was investigated, resulting in both a flat surface and an improvement in crystallinity at temperatures higher than 1150 °C. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computer systems availability evaluation using a segregated failures model
Authors: Vilkomir Sergiy A. , Parnas David L. , Mendiratta Veena B. , Murphy Eamonn 
Published: April 2008

AbstractThis paper presents the segregated failures model (SFM) of availability of fault‐tolerant computer systems with several recovery procedures. This model is compared with a Markov chain model and its advantages are explained. The basic model is then extended for the situation when the coverage factor is unknown and the failure escalation rates must be used instead. A simple practical analytical approach to availability evaluation is provided and illustrated in detail by estimating the availability of two versions of a reliable clustered computing architecture. For these examples, numeric values of availability indexes are computed and the contribution of each recovery procedure to total system availability is analysed. Copyright © 2008 John Wiley & Sons, Ltd.
Estimating selection pressures on HIV‐1 using phylogenetic likelihood models
Authors: Kosakovsky Pond S. L. , Poon A. F. Y. , Zárate S. , Smith D. M. , Little S. J. , Pillai S. K. , Ellis R. J. , Wong J. K. , Leigh Brown A. J. , Richman D. D. , Frost S. D. W. 
Published: April 2008

AbstractHuman immunodeficiency virus (HIV‐1) can rapidly evolve due to selection pressures exerted by HIV‐specific immune responses, antiviral agents, and to allow the virus to establish infection in different compartments in the body. Statistical models applied to HIV‐1 sequence data can help to elucidate the nature of these selection pressures through comparisons of non‐synonymous (or amino acid changing) and synonymous (or amino acid preserving) substitution rates. These models also need to take into account the non‐independence of sequences due to their shared evolutionary history. We review how we have developed these methods and have applied them to characterize the evolution of HIV‐1 in vivo. To illustrate our methods, we present an analysis of compartment‐specific evolution of HIV‐1 env in blood and cerebrospinal fluid and of site‐to‐site variation in the gag gene of subtype C HIV‐1. Copyright © 2008 John Wiley & Sons, Ltd.
Factors affecting enrollment in literacy studies for English‐ and Spanish‐speaking cancer patients
Authors: Du Hongyan , Valenzuela Veronica , Diaz Patricia , Cella David , Hahn Elizabeth A. 
Published: April 2008

AbstractBackground: Study participation bias can affect inferences regarding outcomes.Objective: The objective is to compare characteristics of participants and non‐participants of two literacy studies.Methods: Two studies of literacy and health‐related quality of life were conducted in English‐ and Spanish‐speaking cancer patients. Patients had a range of literacy skills, and each enrolled patient received $20.Results: Nine hundred and twenty‐two English‐speaking patients were approached. Among the 651 who met eligibility criteria, 420 were enrolled (64.5 per cent). Four hundred and eighty‐seven Spanish‐speaking patients were approached. Among the 455 who met eligibility criteria, 414 were enrolled (91.0 per cent) (p<0.001). Multiple imputations were performed to impute missing data. Multivariable logistic regression revealed that recruiting site was the only factor predictive of enrollment in Spanish‐speaking patients. Age, education, and recruiting site were important predictors in English‐speaking patients. Sensitivity analysis using patients with complete data generated similar results.Conclusions: Spanish‐speaking patients enrolled at a much higher rate than English‐speaking patients, which is encouraging for future research in this underserved population. One important literacy‐related factor (education) did not affect enrollment in Spanish‐speaking patients, suggesting that there was no selection bias in this study. Recruiting sites with more indigent patients and long clinic waiting times had higher enrollment, suggesting that monetary compensation and time availability may be important considerations in study participation. Copyright © 2008 John Wiley & Sons, Ltd.
From Healthy Start to Hurricane Katrina: Using GIS to eliminate disparities in perinatal health
Authors: Curtis Andrew 
Published: April 2008

AbstractThis paper provides a summary of the invited talk at the 2007 CDC & ATSDR 11th Biennial Symposium on Statistical Methods conference in which a university‐non‐profit collaboration targeted the elimination of racial disparities in perinatal health with the use of a Geographic Information System (GIS). This program will be described in four temporal stages; the pre‐program early years (1999–2001) where the health burden is defined, leading to the Healthy Start years (2001–2005), in which spatial analyses, methods to effectively disseminate GIS results, the creation of the Baton Rouge Healthy Start database, and a move toward a conceptual goal of creating a holistic neighborhood GIS‐health model are all described. The Katrina years (September 2005–early 2006) portrays the impact of the disaster and how the collaboration changed as resources from both were directed toward both response and recovery. The final section of the paper, the Post‐Katrina years (early 2006 and ongoing) describes how the health landscape of Louisiana, including Baton Rouge as well as New Orleans, has worsened after the storms. An argument is made that the relationships and GIS structure developed during the collaboration's pre‐Katrina years, even though stretched, provide the flexibility to analyze and cope with a Katrina‐type shock to the system. Copyright © 2008 John Wiley & Sons, Ltd.
Modeling and simulation of net centric system of systems using systems modeling language and colored Petri‐nets: A demonstration using the global earth observation system of systems
Authors: Rao Madwaraj , Ramakrishnan Sreeram , Dagli Cihan 
Published: April 2008

AbstractUnderstanding the operations of a large ‘‘net‐centric system‐of‐systems’’ requires in‐depth knowledge of the interfaces and the interactions among the various systems, subsystems, and components. Architectural modeling can help in reducing the complexity involved in designing large networked systems. This paper demonstrates a modeling approach for network centric systems. An example of such a complex system is the Global Earth Observation System of Systems (GEOSS)— a system for monitoring and collecting information related to Earth's resources. The GEOSS is an evolving complex network centric system. The modeling of the GEOSS has been demonstrated using the Systems Modeling Language (SysML). In this paper, architecture representation using SysML demonstrates an object‐oriented approach of model development. This paper discusses issues related to architecture description, development, presentation, and integration for the chosen domain. This paper also highlights some of the differences between SysML, which is used to model a wide range of systems, and Unified Modeling Language (UML), which is primarily used to model information systems only. Finally, in order to synthesize an executable model from the static views developed using SysML, Colored Petri‐nets (CP‐nets) have been used. The executable model, constructed using CP nets, is used to validate the architecture against the static model. Overall, this research defines a methodology to model and simulate complex network centric system of systems in order to understand and simulate their behavior using a scenario based approach. © 2008 Wiley Periodicals, Inc. Syst Eng
Trans-polar-fat: all Inuit are not equal
Authors: Counil Émilie , Dewailly Éric , Bjerregaard Peter , Julien Pierre 
Published: April 2008

As part of the rapid socio-cultural transition observed in Arctic populations, the Inuit diet is changing. We present original data derived from the baseline Inuit Health in Transition cohort study regarding biological levels ofn-3 fatty acids andtrans-fatty acids (TFA), lipids with opposite health effects found respectively in traditional marine diets and recently introduced low-quality imported foods. A total of 524 Inuit from the Disko Bay area (Greenland) and 888 Inuit from the fourteen communities of Northern Québec (Nunavik) participated in the study. We measured the fatty acid profile of erythrocyte (RBC) membrane phospholipids (PL) as a surrogate for individual intakes. Moreover, the contribution of store-bought foods to energy intakes was assessed through dietary questionnaires. Our results show that whilen-3 fatty acid levels were slightly lower in Nunavik (9·4 % of RBC membrane PL) than in Greenland (12·1 %), TFA levels were on average nearly thrice as high in Nunavik Inuit (1·20 %) as they were in Greenlanders (0·43 %). Moreover, younger Nunavik Inuit accumulated higher intakes of TFA and lower intakes ofn-3 fatty acids. Finally, the average proportion of energy derived from store-bought foods was high in both groups (77·5 % and 83·5 %), especially in youth. Our results call for action to rehabilitate and recover access to country foods and point to the importance for Nunavik and the entire circumpolar world to follow the example of Denmark and Greenland, which imposed a maximum content of 2 g/100 g fat on industrially producedtrans-fats in 2003.
Identification of a dietary pattern characterized by high-fat food choices associated with increased risk of breast cancer: the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study
Authors: Schulz Mandy , Hoffmann Kurt , Weikert Cornelia , Nöthlings Ute , Schulze Matthias B. , Boeing Heiner 
Published: April 2008

Epidemiological studies conducted thus far have mainly used a single-nutrient approach which may not be sufficient in detecting diet–cancer relationships. The aim of the study was to examine the association of a food pattern based on explained variations in fatty acid intake by means of reduced rank regression with breast cancer risk. Study participants were female subjects (n 15 351) of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study free of cancer at baseline and with complete dietary and outcome information followed for an average of 6·0 years. Among those, 137 incident cases of invasive breast cancer were identified. We identified a food pattern characterized by low consumption of bread, and fruit juices, and high consumption of processed meat, fish, butter and other animal fats, and margarine explaining >42 % of total variation in fatty acid intake (SFA, MUFA, n-3 PUFA, n-6 PUFA). Intake of all four fatty acid fractions was positively associated with the pattern score. Adherence to this food pattern adjusted for covariates was associated with a two-fold risk (hazard ratio 2·00; 95 % CI 1·30, 3·09) of breast cancer comparing extreme tertiles of the pattern score. There was no evidence of effect modification by menopausal status, overweight status and use of hormone replacement therapy, respectively. In conclusion, a food pattern characterized by high-fat food choices was significantly associated with increased risk of breast cancer. Given that the food pattern was high in all fatty acid fractions, we found evidence for total dietary fat rather than for specific fatty acids to be associated with breast cancer risk.