bluuebunny/crossref_metadata_2025 huggingface dataset:
Persistence with cholinesterase inhibitor therapy in a population‐based cohort of patients with Alzheimer's disease
Authors: Amuah Joseph E. , Hogan David B. , Eliasziw Misha , Supina Alison , Beck Patricia , Downey Winanne , Maxwell Colleen J.
Published: April 2010

Purpose

To estimate the risk (and determinants) of discontinuing cholinesterase inhibitors (ChEIs) in a population‐based sample of Alzheimer's disease (AD) patients.

Methods

This is a retrospective cohort study based on linked de‐identified administrative health data from the province of Saskatchewan, Canada. The cohort included all AD patients receiving a ChEI prescription during the first year of provincial coverage (2000–2001). Persistence was defined as no gap of 60+ days between depletion and subsequent refill of a ChEI prescription. Kaplan‐Meier analysis was used to estimate the risk of discontinuation over 40 months. Cox regression with time‐varying covariates was used to assess risk factors for ChEI discontinuation.

Results

The sample included 1080 patients (64% female, average age 80 ± 7 years). Baseline mean (SD) Mini‐Mental State Examination (MMSE) and Functional Activities Questionnaire (FAQ) scores were 20.8 (4.4) and 17.5 (7.7), respectively. Over 40 months, 84% discontinued therapy. The 1‐year risk of discontinuation was 66.4% (95%CI 63.5–69.3%). Discontinuation was significantly more likely for females (adjusted HR 1.34, 95%CI 1.16–1.55) and among those with lower MMSE scores (2.52, 2.01–3.17 if <15), not receiving social assistance (1.25, 1.07–1.45), and paying at least 65% of total prescription costs (1.51, 1.30–1.74). It was significantly less likely for patients with frequent physician visits (0.78, 0.66–0.93, for 7–19 vs. <7 visits), higher Chronic Disease Scores (0.74, 0.61–0.89, for 7+ vs. <4), and FAQ scores of 9+ (0.82, 0.69–0.99).

Conclusion

The likelihood of discontinuing ChEI therapy was high in this real‐world sample of AD patients. Significant predictors included clinical, socioeconomic, and practice factors. Copyright © 2010 John Wiley & Sons, Ltd.
Characterization of biodegradable semi‐interpenetrating polymer based on poly(vinyl alcohol) and sodium alginate containing natural neem (Azadirachta indica) for controlled release application
Authors: Riyajan Sa‐Ad , Sakdapipanich Jitladda T
Published: May 2010

A biodegradable novel semi‐interpenetrating polymer network based on poly(vinyl alcohol) (PVA) and sodium alginate containing neem (Azadirachta indica) in the presence of azadirachtin‐A (neem Aza‐A) as well as glutaraldehyde as a crosslinking agent was prepared for use in the controlled released of neem Aza‐A. This is necessary because neem Aza‐A is not stable in the environment. The neem Aza‐A‐containing beads were prepared using various experimental parameters, such as the extent of crosslinking and the amount of loading, in order to optimize the process variables. The chemical structure of the capsule wall was evaluated through X‐ray diffraction. In addition, the swelling behaviour of the capsules and their thermal stability were investigated. The strength of the capsule wall depended on the PVA in the matrix and the crosslinking density. Scanning electron microscopy, electron probe microanalysis and atomic force microscopy data indicated that the structure of the bead walls is rough and nonporous. Swelling results indicated that swelling of the polymeric beads decreases with increasing exposure time to the crosslinking agent. At particular intervals, the remaining concentration of neem Aza‐A was analysed using high‐performance liquid chromatography. The release data were fitted to an empirical equation to estimate the kinetic parameters. The degree of release of neem Aza‐A was controlled by the parameter conditions. Copyright © 2010 Society of Chemical Industry
Largely improved tensile extensibility of poly(L‐lactic acid) by adding poly(ε‐caprolactone)
Authors: Chen Long , Yang Jinghui , Wang Ke , Chen Feng , Fu Qiang
Published: May 2010

Poly(L‐lactic acid) (PLLA) has good biocompatibility, biodegradability and physical properties. However, one of the drawbacks of PLLA is its brittleness due to the stiff backbone chain. In this work, a largely improved tensile toughness (extensibility) of PLLA was achieved by blending it with poly(ε‐caprolactone) (PCL). To obtain a good dispersion of PCL in the PLLA matrix, blends were prepared via a solution‐coagulation method. An increase in extensibility of PLLA of more than 20 times was observed on adding only 10 wt% of PCL, accompanied by a slight decrease in tensile strength. However, annealing of the samples led to a sharp decrease of extensibility due to phase separation and a change of crystalline structure. To conserve the good mechanical properties of PLLA/PCL blends, the blends were crosslinked via addition of dicumyl peroxide during the preparation process. For the crosslinked blend films, the extensibility was maintained nearly at the original high value even after annealing. Morphological analysis of cryo‐fractured and etched‐smoothed surfaces of the PLLA/PCL blends was carried out using scanning electron microscopy. Differential scanning calorimetry and polarized light microscopy experiments were used to check the possible change of crystallinity, melting point and crystal morphology for both PLLA and PCL after annealing. The results indicated that the combination of solution‐coagulation and crosslinking resulted in a good and stable dispersion of PCL in the PLLA matrix, which is considered as the main reason for the observed improvement of tensile toughness. Copyright © 2010 Society of Chemical Industry
A novel highly efficient β‐nucleating agent for polypropylene using nano‐CaCO3 as a support
Authors: Zhang Zishou , Chen Chunyan , Wang Chunguang , Junping Zhang , Mai Kancheng
Published: May 2010

In order to increase the isotactic content of β‐nucleated polypropylene (β‐iPP) and decrease the cost of its production, the investigation and development of novel highly efficient β‐nucleators are important issues. Nano‐CaCO3 was used as a support to prepare a supported β‐nucleator, nano‐CaCO3‐supported calcium pimelate. Fourier transform infrared spectral analysis shows that an in situ chemical reaction takes place between nano‐CaCO3 and pimelic acid. Differential scanning calorimetry results indicate that the crystallization and melting temperatures of β‐phase in supported β‐nucleator‐nucleated iPP are higher than those of calcium pimelate‐nucleated iPP. The β‐nucleating ability of the supported β‐nucleator is little influenced by the cooling rate and crystallization temperature over a wide range. The decreased content of pimelic acid in the supported β‐nucleator slightly decreases the crystallization temperature of iPP but it has no influence on the content of β‐phase in nucleated iPP. A novel supported β‐nucleator has been successfully synthesized via pimelic acid supported on the surface of CaCO3. The crystallization temperature of iPP and melting temperature of β‐phase in iPP nucleated using the supported β‐nucleator are higher than those of iPP nucleated using calcium pimelate. The concept of a supported nucleator will provide a new way to increase the efficiency of polymer additives and to decrease the amounts of them that need to be used by using nanoparticles as supports. Copyright © 2010 Society of Chemical Industry
Centralized solar lantern charging station under ‘lighting a billion lives’ campaign: a technological evolution
Authors: Mohanty Parimita , Dasgupta Nivedita , Sharma Arvind
Published: April 2010

To mitigate the use of kerosene for rural lighting and to promote utilization of solar energy, solar lanterns prove to be a viable and promising option. For addressing the issue of large‐scale dissemination of solar lanterns, a rental model is implemented though ‘Lighting a Billion Lives (LaBL)’ campaign. This paper deals with the technological development and customization of the Centralized Solar Lantern Charging Station (CSLCS) under this campaign.

A single unit in a typical LaBL charging station consists of a Solar Photovoltaic (SPV) module feeding a junction box (JB) containing multiple ports for charging of a certain number of lanterns simultaneously. The first version was developed with an available Compact Fluorescent Lamp (CFL) lantern model. The design calculation of the various components considering the various climatic conditions in India and other required parameters are presented. Further, the optimization of the modular design of the charging station based on the above analysis is given. Subsequently, the second version was developed with features addressing the challenges faced in the first version. The field demands and feasibility of incorporating modifications addressing them are reported in detail. Further, a more advanced and customized third version lanterns with additional features was developed. The versions also involved considerable modifications of the JB and lantern circuitry. Comparative analysis of the obtained efficiencies of all the three configurations is presented.

The concluding section proposes methods that lead to the way forward in establishing a more rugged and customized system addressing the issues of seasonal and technological constrains more efficiently. Copyright © 2010 John Wiley & Sons, Ltd.
Highly efficient dye‐sensitized solar cells using phenothiazine derivative organic dyes
Authors: Xie ZhiBin , Midya Anupam , Loh Kian Ping , Adams Stefan , Blackwood Daniel John , Wang John , Zhang Xuanjun , Chen Zhikuan
Published: April 2010

Two novel organic dyes have been synthesized using electron rich phenothiazine as electron donors and oligothiophene vinylene as conjugation spacers. The two dyes (2E)‐2‐cyano‐3‐(5‐(5‐((E)‐2‐(10‐(2‐ethylhexyl)‐10H‐phenothiazin‐7‐yl)vinyl)thiophen‐2‐yl)thiophen‐2‐yl)acrylic acid (PTZ‐1) and (2E)‐3‐(5‐(5‐(4,5‐bis((E)‐2‐(10‐(2‐ethylhexyl)‐10H‐phenothiazin‐3‐yl)vinyl)thiophen‐2‐yl)thiophen‐2‐yl)thiophen‐2‐yl)‐2‐cyanoacrylic acid (PTZ‐2) were fully characterized and employed in dye‐sensitized solar cells (DSCs) to explore the effect of disubstituted donors on photovoltaic (PV) performance. The solar cells sensitized by the PTZ1 dye have a high IPCE plateau of 80% and achieve a short‐circuit photocurrent density of 12.98 mA/cm2, an open‐circuit voltage of 0.713 V, and a fill factor (ff) of 66.6%, corresponding to a conversion efficiency of 6.17% under AM 1.5 100 mW/cm2 illumination. The different performance of the solar cells based on the two dyes can be understood from the studies of the electron kinetics by electrochemical impedance spectroscopy (EIS). These investigations reveal that disubstituted donors in the organic sensitizers of three or more conjugation units deteriorate the PV performance due to enhanced recombination. Copyright © 2010 John Wiley & Sons, Ltd.
Finding diabetic nephropathy biomarkers in the plasma peptidome by high‐throughput magnetic bead processing and MALDI‐TOF‐MS analysis
Authors: Hansen Henning G. , Overgaard Julie , Lajer Maria , Hubalek Frantisek , Højrup Peter , Pedersen Lykke , Tarnow Lise , Rossing Peter , Pociot Flemming , McGuire James N.
Published: April 2010

Purpose and experimental design: Diabetic nephropathy (DN) is the most common cause of end‐stage renal disease and improved biomarkers would help identify high‐risk individuals. The aim of this study was to discover candidate biomarkers for DN in the plasma peptidome in an in‐house cross‐sectional cohort (n=122) of type 1 diabetic patients diagnosed with normo‐, micro‐, and macroalbuminuria.

Results: Automated, high‐throughput, and reproducible (interassay median CV: 13–14%) plasma peptide profiling protocols involving RPC18 and weak cation exchange magnetic beads on a liquid handling workstation with a MALDI‐TOF‐MS readout were successfully established. Using these protocols and a combined univariate (Kruskal–Wallis) and multivariate (independent component analysis) statistical analysis approach, ten single peptides and three multi‐peptide candidate biomarkers were found. Employment of RPC18 and weak cation exchange magnetic beads proved to be complementary.

Conclusions and clinical relevance: The proteins found in this study, including C3f and apolipoprotein C‐I, represent new candidate biomarkers for DN from the plasma peptidome. The automated procedures and implementation of independent components analysis provide a fast and informative system for analyzing individual patient samples in protein biomarker discovery.
Effects of reduced‐rate methyl bromide applications under conventional and virtually impermeable plastic film in perennial crop field nurseries
Authors: Hanson Bradley D , Gerik James S , Schneider Sally M
Published: May 2010

BACKGROUND: Producers of perennial crop nursery stock in California use preplant soil fumigation to meet state phytosanitary requirements. Although methyl bromide (MB) has been phased out in many agricultural industries, it is still the preferred treatment in the perennial nursery industry and is used under Critical Use Exemptions and Quarantine/Preshipment provisions of the Montreal Protocol. The present research was conducted to evaluate reduced‐rate MB applications sealed with conventional and low‐permeability plastic films compared with the primary alternative material.

RESULTS: Reduced rates (100–260 kg ha−1) of MB applied in combination with chloropicrin (Pic) and sealed with a low‐permeability plastic film provided weed and nematode control similar to the industry standard rate of 392 kg ha−1 MB:Pic (98:2) sealed with high‐density polyethylene (HDPE) film. However, the primary alternative chemical, 1,3‐dichloropropene (1,3‐D), tended to provide slightly lower pest control even on sites with relatively low plant parasitic nematode, soil‐borne pathogen and weed pest pressure.

CONCLUSION: If California regulations change to allow the use of low‐permeability films in broadcast fumigant applications, the results of this research suggest that reduced rates of MB in perennial crop nurseries could serve as a bridge strategy until more technically, economically and environmentally acceptable alternatives are developed. Published 2010 by John Wiley & Sons, Ltd.
Multiple P450 genes overexpressed in deltamethrin‐resistant strains of Helicoverpa armigera
Authors: Brun‐Barale Alexandra , Héma Omer , Martin Thibaud , Suraporn Siripuk , Audant Pascaline , Sezutsu Hideki , Feyereisen René
Published: May 2010

BACKGROUND: Resistance to the pyrethroid insecticide deltamethrin has been a growing problem in the management of Helicoverpa armigera (Hübner) pest populations in West Africa. Detoxification by P450 enzymes appears to be a major mechanism of resistance, but the genes responsible for resistance are unknown.

RESULTS: First, it was shown that deltamethrin resistance in strains from Burkina Faso (Kaya) and from Spain (Seville) were suppressible by piperonyl butoxide and by trichlorophenyl propynyl ether, thus indicating a major role of P450 enzyme(s) in resistance. The larval expression of 21 CYP genes encoding P450 enzymes from six CYP families were then compared by quantitative RT‐PCR. Five genes, CYP4L5, CYP4L11, CYP6AE11, CYP332A1 and CYP9A14, were significantly overexpressed in the Kaya and Seville strains when compared with Heliar, a susceptible strain. Significant overexpression of multiple CYP genes (CYP4M6, CYP4M7, CYP6AE11, CYP9A12, CYP332A1 and CYP337B1) was also found in six field strains with different levels of resistance from Benin, Burkina Faso and Mali.

CONCLUSION: Although functional or genetic evidence for the role of these P450s in resistance remains to be formally established, results suggest that multiple P450 enzymes contribute to deltamethrin resistance. This study is a first step towards the development of molecular tools for the detection of P450‐based resistance in H. armigera. Copyright © 2010 Society of Chemical Industry
Behaviour of trifloxystrobin and tebuconazole on grapes under semi‐arid tropical climatic conditions
Authors: Mohapatra Soudamini , Ahuja Ashok K , Deepa M , Jagadish GK , Prakash GS , Kumar Sampath
Published: May 2010

BACKGROUND: A mixture of trifloxystrobin and tebuconazole is excellent in controlling both powdery and downy mildew of grapes. The objective of the present work was to study the behaviour of trifloxystrobin and tebuconazole on grape berries and soil following treatment with Nativo 75 WG, a formulation containing both fungicides (trifloxystrobin 250 + tebuconazole 500 g kg−1). This study was carried out for planned registration of this mixture for use on grapes in India.

RESULTS: Initial residue deposits of trifloxystrobin and tebuconazole on grapes were below their maximum residue limit (MRL) of 0.5 and 2 mg kg−1, respectively, when Nativo 75 WG was applied at the recommended dose of 175 g product ha−1. The residues dissipated gradually to 0.02 and 0.05 mg kg−1 by 30 days, and were below the quantifiable limit of 0.01 mg kg−1 at the time of harvest (60 days after the last treatment). Trifloxystrobin and tebuconazole dissipated at a pre‐harvest interval (PHI) of 36 and 34 days, respectively, from the recommended treatment dose. The acid metabolite of trifloxystrobin, CGA 321 113, was not detected in grape berries at any point in time. Soil at harvest was free of any pesticide residues.

CONCLUSION: Residue levels of both trifloxystrobin and tebuconazole were below MRLs when grapes were harvested 30 days after the last of four applications of 175 g product ha−1 (trifloxystrobin 44 g AI ha−1, tebuconazole 88 g AI ha−1) under the semi‐arid tropical climatic conditions of India. Copyright © 2010 Society of Chemical Industry
Improving current spreading of GaN‐based LEDs by N ‐pad current surrounding design
Authors: Tsai Chun‐Fu , Su Yan‐Kuin , Lin Chun‐Liang
Published: May 2010

In this report, the motivation of why we attempt to design current spreading, or current surrounding, is try to provide other current paths, expect to improve the current spreading of LEDs and get lower forward voltage at the same time. Attempt to avoid the trade‐off between p ‐electrode area for uniform current spreading and emitting area for light output of LEDs.

Compared to reference LEDs, we can find that the light output intensity of chips with n ‐pad current surrounding design will decay at higher current injection. This can be attributed to the metal on pitch we design, with better current spreading and much metal area connected to n ‐pad, so less current crowding effect and less heat‐accumulation in chips (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cyan and green light emitting diode on non‐polar m ‐plane GaN bulk substrate
Authors: Detchprohm Theeradetch , Zhu Mingwei , You Shi , Li Yufeng , Zhao Liang , Preble Edward A. , Paskova Tanya , Hanser Drew , Wetzel Christian
Published: May 2010

We report the development of non‐polar light emitting diodes (LEDs) covering the emission spectra from 480 to 520 nm (dominant wavelength), i.e. from cyan to the green region. The devices are obtained via GaInN‐based homoepitaxy on non‐polar m ‐plane GaN bulk substrate. Owing to the absence of piezoelectric polarization, these LEDs exhibit stable emission color with a wavelength shift less than 3 nm when the drive current density is changed from 0.1–30 A/cm2. However, we observe a decreasing electroluminescence efficiency as the emission wavelengths increases from cyan to green. We tentatively attribute this to a higher density of defects in the longer wavelength structures. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth mechanism of catalyst‐free [0001] GaN and AlN nanowires on Si by molecular beam epitaxy
Authors: Landré O. , Fellmann V. , Jaffrennou P. , Bougerol C. , Renevier H. , Daudin B.
Published: May 2010

Real‐time in‐situ X‐rays scattering experiments were performed to study the nucleation process of GaN nanowires grown by plasma‐assisted molecular beam epitaxy on AlN(0001)/Si(111). From the comparison between the case of nanowires and the case of GaN quantum dots, it is concluded that nanowire precursor islands are completely relaxed from the beginning. Next, based on high resolution electron microscopy analysis, it is demonstrated that relaxation of nanowire precursors is associated to formation of dislocations at the AlN/GaN interface, establishing that three‐dimensional islanding and plastic strain relaxation of GaN are two necessary conditions for nanowire growth. Along the same lines, we demonstrate that three‐dimensional islanding of AlN on SiO2 leads to formation of AlN nanowires with structural and optical properties characteristic of high quality relaxed material (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quaternary nitride heterostructure field effect transistors
Authors: Rahimzadeh Khoshroo L. , Ketteniss N. , Mauder C. , Behmenburg H. , Woitok J. F. , Booker I. , Gruis J. , Heuken M. , Vescan A. , Kalisch H. , Jansen R. H.
Published: May 2010

We report on AlInGaN/AlN/GaN heterostructures on 2′ sapphire substrates with different compositions grown by metal organic vapor phase epitaxy (MOVPE). High‐resolution X‐Ray diffraction (HRXRD) measurements allowed a reliable thickness determination and indicated sharp interfaces. HRXRD mappings showed good quality and single‐phase growth in all barrier layers. At room temperature, the samples yielded average two‐dimensional carrier densities in the range of 1.51 – 1.81 × 1013 cm‐2, systematically decreasing with rising GaN content in the barrier layer. Room temperature (RT) mobilities up to 1790 cm2/Vs were measured. When cooled to 77 K, the sheet resistivity decreased to 37% of the RT value at no noticeable change of ns. Atomic force microscopy reveals very low roughness and improved step‐flow morphology. Further processing yielded high electron mobility transistors exhibiting a transconductance of around 265 mS/mm for all samples and drain currents ranging from 848 mA/mm to 1051 mA/mm at 0 V gate voltage (Lg = 1 μm) (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dislocation density assessment via X‐ray GaN rocking curve scans
Authors: Booker I. , Rahimzadeh Khoshroo L. , Woitok J. F. , Kaganer V. , Mauder C. , Behmenburg H. , Gruis J. , Heuken M. , Kalisch H. , Jansen R. H.
Published: May 2010

The line shape of X‐ray diffraction (XRD) rocking curves of GaN layers grown epitaxially on (0001) oriented sapphire substrates is analyzed. Measurements performed with double‐ and triple‐crystal setup show a q‐3 and q‐4 intensity decay, respectively, as expected for peak broadening dominated by randomly distributed dislocations. A model developed in [2], based on a restricted random dislocation distribution is fitted to the entire peak shape and used to extract dislocation densities and correlation lengths for edge and screw type threading dislocations. Parameters extracted by double‐ and triple‐crystal x‐ray diffraction measurements agree well with each other but still must be verified by systematic cross‐sectional TEM measurements. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
P‐type doping of semipolar GaN(11$ \bar 2 $2) by plasma‐assisted molecular‐beam epitaxy
Authors: Das A. , Lahourcade L. , Pernot J. , Valdueza‐Felip S. , Ruterana P. , Laufer A. , Eickhoff M. , Monroy E.
Published: May 2010

We report the effect of Mg doping on the growth kinetics of semipolar GaN(11‐22) synthesized by plasma‐assisted molecular‐beam epitaxy. Mg tends to segregate on the surface, inhibiting the formation of the self‐regulated Ga film which is used as a surfactant for the growth of undoped and Si‐doped GaN(11‐22). As a result, the growth widow is reduced for Mg doped layers, and we observe a certain deterioration of the surface morphology. In spite of this difficulties, homogenous Mg incorporation is achieved and layers display p ‐type conductivity for Mg atomic concentration higher than 7×1018 cm‐3. Microscopy studies show no evidence of the pyramidal defects or polarity inversion domains found in Mg‐doped GaN(0001). (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of field emitters using GaN particles
Authors: Minakuchi Yuichiro , Neo Yoichiro , Mimura Hidenori , Hara Kazuhiko
Published: May 2010

The field emission from GaN particles has been demonstrated successfully for the first time. The novel field emitting device has a simple structure consisting of an electrically conductive polymer layer and GaN particles spread randomly on it. The GaN particles used for this device, which were synthesized in advance by the two‐stage vapor phase method, have vertices and ridges formed by well‐developed crystal planes. The electron emission started at an electric field of about 20 V/μm, and the current reached 10 nA at 28 V/μm. The maximum current density was 0.26 mA/cm2at 43 V/μm. The Fowler‐Nordheim (F‐N) plot of the I ‐V data indicated that the observed electron emission is originated from the F‐N tunneling. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Downstream effects of diversion dams on sediment and hydraulic conditions of Rocky Mountain streams
Authors: Baker D. W. , Bledsoe B. P. , Albano C. M. , Poff N. L.
Published: May 2010

Reduced streamflow via flow diversion has the potential to limit the sediment‐transport capacity of downstream channels and lead to accumulation of fine sediments and habitat degradation. To investigate, we examined the effects of variable levels of flow diversion on fine‐sediment deposition, hydraulic conditions and geomorphic alteration. Our study consisted of a detailed field analysis pairing reaches above and below diversion dams on 13 mountain streams in north‐central Colorado and southern Wyoming USA. Diversions are ubiquitous across the American West, yet previous comparative studies on the effects of flow diversion have yielded mixed results. Through application of strict site‐selection criteria, multiple fine‐sediment measures, and an intensive sampling scheme, this study found that channels downstream of diversions contained significantly more fine sediment and slow‐flowing habitat as compared to upstream control reaches. Susceptibility to fine‐sediment accumulation was associated with decreasing basin size, decreasing bankfull depth and smaller d84, and it appears to be magnified in streams of less than 3% slope. Copyright © 2010 John Wiley & Sons, Ltd.
Stable isotope analysis reveals food web structure and watershed impacts along the fluvial gradient of a Mesoamerican coastal river
Authors: Winemiller Kirk O. , Hoeinghaus David J. , Pease Allison A. , Esselman Peter C. , Honeycutt Rodney L. , Gbanaador Donmale , Carrera Elizabeth , Payne Josiah
Published: May 2010

Ecosystem processes and biological community structure are expected to change in a relatively predictable manner along fluvial gradients within river basins. Such predictions are heavily based on temperate rivers, and food web variation along fluvial gradients in Mesoamerican rivers has received limited attention. In this study, we analyzed carbon and nitrogen stable isotope ratios of basal carbon sources and dominant consumer species to examine aquatic food web structure along the fluvial gradient of the Monkey River Basin, Belize. Similar to previous studies in other regions, consumer species richness and functional diversity increased along the downstream fluvial gradient, due in part to the addition of estuarine species in lower reaches and increasing diversity of piscivorous species along the gradient. Aquatic food webs in upstream reaches were primarily supported by allochthonous production sources, and in‐stream sources increased in importance along the downstream gradient. Our study system traversing the Maya Mountain Marine Area Transect also provided a unique opportunity to test the utility of primary consumer δ15N as an indicator of watershed impacts within a tropical basin with a diverse biota and a different type of agricultural impact than typically studied (i.e. banana plantations vs. tilled row cropping). As expected, primary consumer δ15N at sites draining impacted watersheds was enriched compared to values from forested reference sites. Assessment of primary consumer δ15N may be a feasible option for monitoring watershed impacts on aquatic food webs in service of the ridge‐to‐reef conservation strategy adopted for this watershed as well as in other tropical river basins. Copyright © 2010 John Wiley & Sons, Ltd.
Sustainable development as a community of practice: insights from rural water projects in Egypt
Authors: Armanios Daniel Erian
Published: April 2010

A community‐of‐practice (CoP) approach is used to analyze rural water sustainability. In combining CoP with the capability approach (CA), a dichotomy is generated between project goals and project practices and whether they are locally or externally driven. Four possible project scenarios are developed from this framework: empowerment (local goals and practices), apprenticeship (local practices and external goals), assistencialism (external practices and local goals) and determinism (external goals and practices). A novel arrangement of indicators is used that incorporates economic (costs), environmental (natural resources) and engineering (skills) sustainability. A meta‐synthesis of 23 Egyptian rural water projects indicates that sustainability potential should optimize environmental and engineering sustainability on one hand, with economic sustainability on the other. The policy implication is that managing a series of village‐level water projects at a regional level best achieves both economy of scale and adequate cultivation of local practices. However, such a policy is only possible if national institutions enable decentralized regional governance. If institutions resist decentralization, institutional incentives are likely necessary to ensure a more enabling environment. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
Surface characterization of activated carbons obtained from olive bagasse by chemical activation
Authors: Demiral İlknur , Demiral Hakan
Published: April 2010

In this study, activated carbons were prepared from olive bagasse by chemical activation using H3PO4. Chemical activation was carried out by mixing the solution of H3PO4 and olive bagasse with a chemical agent/waste ratio (wt/wt) varying from 1 to 4. The carbonization treatment was performed at 400, 500, 600 and 700 °C. The pore properties including surface area, pore volume, pore size distribution and average pore diameter of the activated carbons were determined by N2 adsorption at 77 K using the Brunauer–Emmett–Teller (BET), t‐plot and density functional theory (DFT) methods. The highest surface area and total pore volume of the activated carbon were 936 m2/gand 0.598 cm3/g, respectively. The pore size distribution showed that the activated carbons include both micro and mesopores. Under the experimental conditions employed, a carbonization temperature of 400 °C with an impregnation ratio of 4 was found to be suitable for producing activated carbon of high surface area. Surface morphologies of the olive bagasse and the activated carbon were investigated by SEM. According to the experimental results, olive bagasse is a suitable raw material for activated carbon production. Copyright © 2010 John Wiley & Sons, Ltd.
Comparing the IR spectra of H‐terminated inner and outer silicon surfaces
Authors: Romano E. , Cerofolini G. F. , Narducci D. , Galati C. , Renna L.
Published: May 2010

An array of nanocavities in silicon offers an inner surface defined by nearly flat, highly ordered, planes which can be passivated by hydrogen injection from aqueous solution of HF. The infrared spectrum shows that the inner surface is mainly constituted by monohydrides in different morphologies. The corresponding signals are very narrow (full width at half maximum at room temperature below 5 cm−1, depending on the line), this being evidence for high local order. Such an inner surface can be used as a benchmark for the assignment of infrared signals observed on outer surfaces, where the sources of errors—and the consequent uncertainty in the spectral attribution—may be large. The comparison between the spectra from a well‐characterized external Si(1 0 0) surface and from an internal one (in both cases hydrogen‐terminated) has allowed a better qualification of the external surface. Copyright © 2010 John Wiley & Sons, Ltd.
SIMS using negative primary ion bombardment
Authors: Pillatsch L. , Wirtz T. , Migeon H.‐N. , Scherrer H.
Published: May 2010

Dynamic secondary ion mass spectrometry (D–SIMS) is an extremely powerful analysis technique for studying surfaces and thin films. The development of ion sources using electronegative elements is necessary to optimize the analysis of the electropositive elements. In this paper, we present SIMS analyses carried out with an F− primary ion beam. We discuss the performance of the duoplasmatron ion source operated with different gas mixtures in order to extract F− primary ions. The brightness of the F− ion beam was calculated and found to be superior to that obtained with an O− ion beam. Finally, we compare the useful yields of positive secondary ions obtained with F− bombardment to those determined for O− primary ions. Copyright © 2010 John Wiley & Sons, Ltd.
Titanium layers on aluminum bond pads: Characterisation of thin layers on rough substrates
Authors: Puchner S. , Zechmann A. , Detzel Th. , Hutter H.
Published: May 2010

A big challenge in the semiconductor industry is to control surface contamination, especially on bond pads, since they might take influence on bond wire adhesion and reliability behavior. The impact of fluorine and organic contamination on wire bonding is already well documented.1Nevertheless, the influence of metal contamination has not yet been investigated in detail.

As titanium contamination has been found on bond pad surfaces, owing to some manufacturing process steps, this presentation concerns preliminary investigations on titanium‐contaminated aluminum structures.

Titanium layers of different thicknesses in the nanometer range have been deposited by means of physical vapor deposition, either directly after aluminum deposition, or after an air break, in order to study their influence on wire bond quality in a systematic manner.

Depth profile measurements have been carried out by means of TOF‐SIMS. In order to study the oxide and the titanium distribution, those measurements have been performed in positive and negative modes.

To overcome the big challenge to distinguish between the thicknesses of thin layers in the nanometer scale, depth profiling parameters were optimized regarding signal intensities.

This work deals with our analytical results and shows the possibility to clearly identify nanoscale layers and interdiffusion areas between different materials by enhanced depth resolution. In the near future, we will quantitatively investigate the impact of different titanium contaminations on bond pads on the adherence of Al‐wedge bonds. Copyright © 2010 John Wiley & Sons, Ltd.
Enhanced dendritic availability of μ‐opioid receptors in inhibitory neurons of the extended amygdala in mice deficient in the corticotropin‐releasing factor‐1 receptor
Authors: Jaferi Azra , Zhou Ping , Pickel Virginia M.
Published: April 2010

Activation of the corticotropin‐releasing factor‐1 (CRF‐1) receptor in the anterolateral BNST (BSTal), a key subdivision of the extended amygdala, elicits opiate‐seeking behavior exacerbated by stress. However, it is unknown whether the presence of CRF‐1 affects expression of the μ‐opioid receptor (μ‐OR) in the many GABAergic BSTal neurons implicated in the stress response. We hypothesized that deletion of the CRF‐1 receptor gene would alter the density and/or subcellular distribution of μ‐ORs in GABAergic neurons of the BSTal. We used electron microscopy to quantitatively examine μ‐OR immunogold and γ‐aminobutyric acid (GABA) immunoperoxidase labeling in the BSTal of CRFr‐1 knockout (KO) compared to wild‐type (WT) mice. To assess regional specificity, we examined μ‐OR distribution in dorsal striatum. The μ‐ORs in each region were predominantly localized in dendrites, many of which were GABA‐immunoreactive. Significantly, more cytoplasmic μ‐OR gold particles per dendritic area were observed selectively in GABA‐containing dendrites of the BSTal, but not of the dorsal striatum, in KO compared to WT mice. In both regions, however, significantly fewer GABA‐immunoreactive axon terminals were present in KO compared to WT mice. Our results suggest that the absence of CRF‐1 results in enhanced expression and/or dendritic trafficking of μ‐ORs in inhibitory BSTal neurons. They also suggest that the expression of CRF‐1 is a critical determinant of the availability of GABA in functionally diverse brain regions. These findings underscore the complex interplay between CRF, opioid, and GABA systems in limbic and striatal regions and have implications for the role of CRF‐1 in influencing the pharmacological effects of opiates active at μ‐ORs. Synapse 65:8–20, 2011. © 2010 Wiley‐Liss, Inc.
Feedback‐based multi‐layered STBC system for MIMO multi‐cellular networks with cochannel interference
Authors: Wang Jui Teng
Published: May 2010

A feedback‐based multi‐layered STBC (MLSTBC) system, which is adapted to cochannel interference, is proposed. This system can adjust its transmitter configuration so that the largest throughput for the given SINR is obtained, also, it can use joint beamforming and power control to minimize cochannel interference so that the throughput requirement is satisfied. We propose an iterative algorithm to realize joint beamforming and power control for the feedback‐based MLSTBC system, and in this algorithm, we derive the required SINR and the corresponding transmitter configuration for attaining the throughput requirement. Some properties and simulation results are presented, they show that the proposed algorithm helps the feedback‐based MLSTBC system increase the probability of the success in meeting the throughput requirement, also they show that the feedback‐based MLSTBC system results in larger throughput than MLSTBC (with fixed transmitter configuration), STBC, and V‐BLAST. Copyright © 2010 John Wiley & Sons, Ltd.
Distributed grid‐type architectures
Authors: Alnoshan Abdullah A. , Rotenstreich Shmuel
Published: May 2010

Research advances in the distributed computing have led to grid computing, which unlike many other areas of distributed computing focuses on large‐scale resource sharing and discovery for better performance. Traditionally, grid computing has been performed in a client/server format. However, recent advances in the area of peer‐to‐peer computing have brought a paradigm shift in the field of distributed systems and have forced researchers in the area of grid computing to discuss peer‐to‐peer grids. In this article, we will review the work done in the area of grid computing and discuss peer‐to‐peer grids with a focus on a framework that provides incentive to the participating resources in a peer‐to‐peer grid environment. The framework provides the basis for defining a utility function that is used by participating nodes to efficiently allocate the resources that are available in a system. We finish by mentioning the evolving area of cloud computing. Copyright © 2010 John Wiley & Sons, Inc.

This article is categorized under:

Software for Computational Statistics > High Performance Software
The quorum‐sensing molecule E,E‐farnesol—its variable secretion and its impact on the growth and metabolism of Candida species
Authors: Weber K. , Schulz B. , Ruhnke M.
Published: May 2010

Diseases caused by Candida species are an increasing problem. Candida species are associated with high overall mortality, due to a variety of virulence factors such as the yeast‐to‐hyphal switch and proteolytic enzymes. The phenomenon of microbial communication known as quorum sensing also seems to play an important role. The main characteristics of the quorum‐sensing molecule E,E‐farnesol are well known for C. albicans. The present study focused on two questions. One of them concerned the secretion of E,E‐farnesol by C. albicans and involved a close examination of the effect of the medium (serum) and the origin of the isolates used. The second one dealt with the activity of E,E‐farnesol in non‐C. albicans species, such as C. tropicalis and C. parapsilosis, e.g. its impact on biofilm formation and growth. Under serum conditions, C. albicans produced up to 58% more E,E‐farnesol at 37 °C than at 30 °C. The growth of all isolates was reduced and delayed by the administration of E,E‐farnesol. Of all Candida species, C. tropicalis isolates were most strongly affected by the addition of E,E‐farnesol. Biofilm formation on polystyrene was affected by E,E‐farnesol treatment in all non‐C. albicans species and C. albicans. E,E‐farnesol exerts its main effect by altering the metabolic activity and growth inhibition of treated Candida species. The results obtained indicate that the presence of E,E‐farnesol in the environment not only regulates the morphology of the Candida species but also affects its fitness. In this regard, the secretion of E,E‐farnesol might provide an advantage for members of the microbial community. Copyright © 2010 John Wiley & Sons, Ltd.
Adverse life events and mental health in middle adolescence
Authors: Flouri Eirini , Kallis Constantinos
Published: May 2010

This study’s aim was to search for the appropriate functional form of the effect of proximal cumulative contextual risk (PCCR), measured with number of adverse life events experienced in the last 6 months, on adolescent psychopathology and prosocial behavior, measured with the Strengths and Difficulties Questionnaire. The study sample was 171 year ten (aged 14–15) adolescents from predominantly socio‐economically disadvantaged families in the UK. Adjustment was made for parental education, and for child’s age, gender, and academic achievement, which was measured with results in Standard Attainment Tests in English, mathematics and science taken in the previous year. PCCR predicted total difficulties, emotional symptoms, conduct problems and hyperactivity. The relationship between PCCR and total difficulties and emotional symptoms was non‐quadratic; the PCCR/externalizing problems relationship was quadratic. The findings highlight the importance of considering both outcome specificity and non‐linear patterns of associations when modelling cumulative contextual risk effects on adolescent psychopathology.
Comparison of brain N-acetylaspartate levels and serum brain-derived neurotrophic factor (BDNF) levels between patients with first-episode schizophrenia psychosis and healthy controls
Authors: Goto N. , Yoshimura R. , Kakeda S. , Moriya J. , Hayashi K. , Ikenouchi-Sugita A. , Umene-Nakano W. , Hori H. , Ueda N. , Korogi Y. , Nakamura J.
Published: May 2010

Background:

N-acetylaspartate (NAA) levels and serum brain-derived neurotrophic factor (BDNF) levels in patients with first-episode schizophrenia psychosis and age- and sex-matched healthy control subjects were investigated. In addition, plasma levels of homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were compared between the two groups.

Method:

Eighteen patients (nine males, nine females; age range: 13–52 years) were enrolled in the study, and 18 volunteers (nine males, nine females; age range: 15–49 years) with no current or past psychiatric history were also studied by magnetic resonance spectroscopy (MRS) as sex- and age-matched controls.

Results:

Levels of NAA/Cr in the left basal ganglia (p = 0.0065) and parieto-occipital lobe (p = 0.00498), but not in the frontal lobe, were significantly lower in patients with first-episode schizophrenia psychosis than in control subjects. No difference was observed between the serum BDNF levels of patients with first-episode schizophrenia psychosis and control subjects. In regard to the plasma levels of catecholamine metabolites, plasma MHPG, but not HVA, was significantly lower in the patients with first-episode psychosis than in control subjects. In addition, a significantly positive correlation was observed between the levels of NAA/Cr of the left basal ganglia and plasma MHPG in all subjects.

Conclusions:

These results suggest that brain NAA levels in the left basal ganglia and plasma MHPG levels were significantly reduced at the first episode of schizophrenia psychosis, indicating that neurodegeneration via noradrenergic neurons might be associated with the initial progression of the disease.
Protein deacetylase SIRT1 in the cytoplasm promotes nerve growth factor‐induced neurite outgrowth in PC12 cells
Authors: Sugino Toshiya , Maruyama Mitsuhisa , Tanno Masaya , Kuno Atsushi , Houkin Kiyohiro , Horio Yoshiyuki
Published: May 2010

SIRT1, a NAD+‐dependent protein deacetylase, is known to have neural functions. However, despite its cytoplasmic expression in some neural cells, its cytoplasmic function, if any, is unknown. Here we found that PC12 (pheochromocytoma) cells expressed SIRT1 in the cytoplasm. Nerve growth factor (NGF)‐induced neurite outgrowth of these cells was promoted by activators of SIRT1, while inhibitors of SIRT1 or SIRT1‐siRNA significantly inhibited it. The overexpression of a mutant SIRT1 that localised to the cytoplasm but not the nucleus enhanced the NGF‐dependent neurite outgrowth, and a cytoplasmic dominant‐negative SIRT1 suppressed it. Thus, cytoplasmic SIRT1 increases the NGF‐induced neurite outgrowth of PC12 cells.
Rho‐kinase mediates lysophosphatidic acid‐induced IL‐8 and MCP‐1 production via p38 and JNK pathways in human endothelial cells
Authors: Shimada Hideaki , Rajagopalan Lakshman E.
Published: May 2010

Lysophosphatidic acid (LPA), an inflammatory mediator that is elevated in multiple inflammatory diseases, is a potent activator of Rho kinase (ROCK) signaling and of chemokine production in endothelial cells. In this study, LPA activated ROCK, p38, JNK and NF‐κB pathways and induced interleukin‐8 (IL‐8) and monocyte chemotactic protein‐1 (MCP‐1) mRNA and protein expression in human endothelial cells. We mapped signaling events downstream of ROCK, driving chemokine production. In summary, MCP‐1 production was partly regulated by ROCK acting upstream of p38 and JNK and mediated downstream by NF‐κB. IL‐8 production was largely driven by ROCK through p38 and JNK activation, but with no involvement of NF‐κB.
Prothymosin α is a component of a linker histone chaperone
Authors: George Eric M. , Brown David T.
Published: May 2010

Linker histone H1 binds with high affinity to naked and nucleosomal DNA in vitro but is rapidly exchanged between chromatin sites in vivo suggesting the involvement of one or more linker histone chaperones. Using permeabilized cells, we demonstrate that the small acidic protein prothymosin α (ProTα) can facilitate H1 displacement from and deposition onto the native chromatin template. Depletion of ProTα levels in vivo by siRNA‐mediated mRNA degradation resulted in a decreased rate of exchange of linker histones as assayed by photobleaching techniques. These results indicate that ProTα is a component of a linker histone chaperone.