bluuebunny/crossref_metadata_2025 huggingface dataset:
Full color light‐emitting electrospun nanofibers prepared from PFO/MEH‐PPV/PMMA ternary blends
Authors: Chen Hsieh‐Chih , Wang Cheng‐Ting , Liu Cheng‐Liang , Liu Yu‐Cheng , Chen Wen‐Chang
Published: January 2009

In this study, luminescence electrospun (ES) nanofibers based on ternary blends of poly(9,9‐dioctylfluoreny‐2,7‐diyl) (PFO)/poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV)/poly(methyl methacrylate) (PMMA) were prepared from chloroform solutions using a single capillary spinneret. Effects of PFO/MEH‐PPV ratio on the morphology and photophysical properties were studied while the PMMA weight percentage was fixed at 90 wt %. The morphologies of the prepared ES fibers were characterized by FE‐SEM and fluorescence microscopy. The obtained fibers had diameters around a few hundred nm and pore sizes in the range of 30–35 nm. The emission colors of the PFO/MEH‐PPV/PMMA blend ES fibers changed from blue, white, yellowish‐green, greenish‐yellow, orange, to yellow, as the MEH‐PPV composition increased. In contrast, the emission colors of the corresponding spin‐coated films were blue, orange, pink‐red, red, and deep‐red. Based on the values of solubility parameters, the PFO and MEH‐PPV are miscible to each other and trapped in the PMMA matrix. Hence, energy transfer between these two polymers is possible. The smaller aggregated domains in the ES fiber compared to those of spin‐coated films possibly reduce the efficiency of energy transfer, leading to different emission colors. Also, the prepared ES fibers had higher photoluminescence efficiencies than those of the spin‐coated films. Pure white light‐emitting fibers prepared from the PFO/MEH‐PPV/PMMA blend ratio of 9.5/0.5/90 had the Commission Internationale de L'Eclairage (CIE) coordinate of (0.33, 0.31). Our results showed that different color light‐emitting ES fibers were produced through optimizing the composition of semiconducting polymer in the transparent polymer matrix. This type of ES fibers could have potential applications as new light sources or sensory materials for smart textiles. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 463–470, 2009
Organic–inorganic hybrid hydrogels involving poly(N‐isopropylacrylamide) and polyhedral oligomeric silsesquioxane: Preparation and rapid thermoresponsive properties
Authors: Zeng Ke , Fang Yuan , Zheng Sixun
Published: January 2009

3‐Acryloxypropylhepta(3,3,3‐trifluoropropyl) polyhedral oligomeric silsesquioxane (POSS) was synthesized and used as a modifier to improve the thermal response rates of poly(N‐isopropylacrylamide) (PNIPAM) hydrogel. The radical copolymerization among N‐isopropylacrylamide (NIPAM), the POSS macromer and N,N′‐methylenebisacrylamide was performed to prepare the POSS‐containing PNIPAM cross‐linked networks. Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) showed that the POSS‐containing PNIPAM networks displayed the enhanced glass transition temperatures (Tg's) and improved thermal stability when compared with plain PNIPAM network. The POSS‐containing PNIPAM hydrogels exhibited temperature‐responsive behavior as the plain PNIPAM hydrogels. It is noted that with the moderate contents of POSS, the POSS‐containing PNIPAM hydrogels displayed much faster response rates in terms of swelling, deswelling, and re‐swelling experiments than plain PNIPAM hydrogel. The improved thermoresponsive properties of hydrogels have been interpreted on the basis of the formation of the specific microphase‐separated morphology in the hydrogels, that is, the POSS structural units in the hybrid hydrogels were self‐assembled into the highly hydrophobic nanodomains, which behave as the microporogens and promote the contact of PNIPAM chains and water. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 504–516, 2009
Optical properties of MOCVD HfO2 films
Authors: Ayupov Boris , Zherikova Kseniya , Gelfond Nikolai , Morozova Natalia
Published: January 2009

Hafnium(IV) 2,2,6,6‐tetramethylheptane‐3,5‐dionate Hf(thd)4 was used for depositing HfO2 coatings by MOCVD in vertical reactor in different conditions. Monochromatic null ellipsometry was applied to characterize the film thickness and refractive index using different optical model of samples. The definition of sample optical anisotropy points to the growth of HfO2 nanocrystals during film annealing. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and optical properties of Eu2+ doped CaGa2S4–CaS composite bicolor phosphor for white LED
Authors: Jabbarov R. , Musayeva N. , Scholz F. , Wunderer T. , Turkin A. N. , Shirokov S. S. , Yunovich A. E.
Published: January 2009

In the present paper, we report the optical properties of the bicolor composite phosphor on the base of CaS and Ga2S3 and study the possibility using this composite to obtain a white light LED. In particular, the energy transfer between the green and red emission bands of the bicolor composite phosphor activated by Eu2+ ions was studied. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic and dielectric properties of pure and doped barium hexaferrite nanoparticles at microwave frequencies
Authors: Dimri Mukesh C. , Stern R. , Kashyap Subhash C. , Bhatti K. P. , Dube D. C.
Published: January 2009

Preparation of barium hexaferrite nanoparticles by chemical route and investigations of their dielectric and magnetic properties at microwave frequencies (8–12 GHz) are reported in the present paper. Measurements of these properties were carried out at microwave frequencies by using a cavity perturbation technique. It is observed that the values of the permittivity and permeability of nanoparticles are lower than the corresponding values for the bulk material. The effects of particle size, calcination temperature and compositional dependence on structural, microstructural and magnetic properties are also discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural evolution and visible photoluminescence of Zn–ZnO nanophosphor
Authors: Ghosh Avijit , Choudhary R. N. P.
Published: January 2009

The Zn–ZnO nanostructure thin films are prepared by an inexpensive vacuum arc‐discharge method combined with vacuum annealing. The structural analysis of the grazing‐incidence X‐ray diffraction pattern using the Rietveld method showed the formation of Zn–ZnO in a single phase. The coexistence of Zn and ZnO in the thin‐film sample was also confirmed using transmission electron microscopy technique. Studies of optical properties by photoluminescence (PL) spectroscopy exhibit a strong violet emission accompanied by weak blue and green emission. The origin of defect emission of Zn–ZnO nanostructure was analyzed. Thus, the existence of metallic Zn nanocrystals embedded in ZnO islands provides a considerable change in the PL mechanism. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic field dependences of galvanomagnetic properties of polycrystalline Bi–Sb solid solutions
Authors: Rogacheva E. I. , Drozdova A. A. , Izhnin I. I. , Dresselhaus M. S.
Published: January 2009

The dependences of the Hall coefficientRHand magnetoresistance Δρ/ρon magnetic field (B= 0.01–1.0 T) for polycrystalline Bi–Sb solid solutions with various Sb concentrations (0–15 at% Sb) were obtained at 77 K and 300 K. On the basis of theRH(B) and Δρ/ρ(B) dependences, the values of magnetic fieldBccorresponding to the boundary of the region characterized by a constancy ofRHand a quadratic dependence of Δρ/ρ(B), i.e. satisfying the criterion of weak magnetic field behavior, were determined. It was established that a decrease in temperature leads to a shift of the critical valuesBcto smaller magnetic fields. It was shown that the dependence ofBcon composition of Bi–Sb solid solutions exhibits a non‐monotonic behavior: in the vicinity of ∼3 at% Sb and ∼8 at% Sb, where distinct minima are observed. The appearance of the minima was attributed to a sharp increase in the charge carrier mobility at the mentioned Sb concentrations due to the transition to a gapless state accompanied by the band inversion, and to the semimetal–semiconductor transition, respectively. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
CMOS‐compatible nanoscale gas‐sensor based on field effect
Authors: Velasco‐Velez J. J. , Chaiyboun A. , Wilbertz C. , Woellenstein J. , Bauersfeld M. , Doll T.
Published: January 2009

The integration of a solid state gas sensor of the metal oxide sensor type into CMOS technology still is a challenge because of the high temperatures during metal oxide annealing and sensor operation that do not comply with silicon device stability. In the presence of an external electric field sensor sensitivity can be controlled through a change of the Fermi energy level and consequently it is possible to reduce the operation temperature. Based in this effect, a novel field effect gas sensor was developed resembling a reversed insulated gate field effect transistor (IGFET) with the thickness of gas sensing layer in the range of the Debye length (LD). Under these conditions the controlling electrical field reaches the sensitive surface and a modulation of the Fermi energy level occurs, producing an effective control of gas sensitivity and sensor response. In this paper several aspects are treated, like technological fabrication process, complete sensor characterization by means of an electrical model and sensor response measurements. Other effects as base‐line drift effects and layer thickness implications also are studied. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low vacuum photo electron emitting thin films
Authors: Zimmer C. , Medyanyk K. , Schoenhense G. , Krischok S. , Lorenz P. , Schubert J. , Doll T.
Published: January 2009

Impact ionisation is a standard procedure to ionise gaseous or vaporisable substances in organic mass spectrometry. In this work, a “softer” ionisation is introduced which seems to be an alternative ion source for reducing collision between substance molecules and the hot internal walls of the box. Through collision mainly found in impact ionisation sources, fragments are built especially from thermally sensitive substances falsifying the spectra. We present here photoelectron emitting materials for the soft ionisation using semiconducting compounds, galliumn nitride (GaN), and a representative of the borides, lanthanum hexaboride (LaB6). They are evaluated by photoelectron spectroscopic studies. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical insulation properties of sputter‐deposited SiO2, Si3N4 and Al2O3 films at room temperature and 400 °C
Authors: Bartzsch Hagen , Glöß Daniel , Frach Peter , Gittner Matthias , Schultheiß Eberhard , Brode Wolfgang , Hartung Johannes
Published: January 2009

In this paper the breakdown field strength and resistivity of sputter‐deposited Al2O3, SiO2 and Si3N4 layers are investigated in the temperature range between room temperature and 400 °C. All the investigated layers showed excellent insulation properties, even at elevated sample temperature. One example of industrial application is the deposition of electrical insulation layers onto the membranes of pressure sensors using cluster type sputter equipment
A stochastic lightning‐flash scheme for 3D explicitly resolving cloud models
Authors: Molinié G. , Escobar J. , Gazen D.
Published: January 2009

The paper presents a stochastic lightning‐flash scheme designed for mesoscale cloud‐resolving models (MCRMs). The lightning‐flash scheme is implemented on‐line in an MCRM. It is fully parallellized and vectorized.

A lightning flash is schematized as two single conducting channels (single tracks) propagating in opposite directions from the lightning ignition point, and of branch patterns propagating from the single tracks. On the base of scale similarities between lightning flashes and discharges in dielectrics at centimetre scales, a stochastic scheme has been designed to compute branch trajectories. A fractal relationship is used to limit the branch number. Charge neutralization operates along the single tracks and branch trajectories to threshold the cloud charge density.

The scheme has been implemented in the French meteorological community model MésoNH. Two kinds of tests were designed to assess the scheme's capabilities. A first set consists of single‐lightning simulations, which demonstrate that, thanks to branches, the simulated lightning flashes are (i) able to reach sparse electric charges and (ii) are fractal objects. The second set consists of comprehensive 3D‐thundercloud life‐cycle simulations. A simple non‐inductive charging process is activated in order to assess the sensitivity of thundercloud electrical behaviour to lightning patterns. It is shown that, paradoxically, lightning flashes with quasi‐plane branch propagations (i.e. fractal dimension close to 2) lead to more steady electrical behaviour than those completely filling volumes (i.e. fractal dimension close to 3). Copyright © 2009 Royal Meteorological Society
Monitoring the observation impact on the short‐range forecast
Authors: Cardinali Carla
Published: January 2009

This paper describes the use of forecast sensitivity to observations as a diagnostic tool to monitor the observation impact on the 24‐hour forecast range. In particular, the forecast error is provided by the control experiments (using all observations available) of two sets of observing system experiments performed at ECMWF, a month in summer 2006 and a month in winter 2007, respectively. In such a way, the observation data impact obtained with the forecast sensitivity is compared with the observing system experiment's data impact; differences and similarities are highlighted. Globally, the assimilated observations decrease the forecast error; locally, some poor performances are detected that are related either to the data quality or to the suboptimality of the data assimilation system. It is also found that the synoptic situation can affect the measurements or can produce areas of large field variability that the assimilation system cannot model correctly. Copyright © 2009 Royal Meteorological Society
Review of multinomial and multiattribute quality control charts
Authors: Topalidou Elisabeth , Psarakis Stelios
Published: January 2009

Attribute control charts are very useful nowadays for monitoring processes where the quality characteristics cannot be measured in a continuous scale, which may be manufacturing processes from industrial settings, health‐care processes or processes from service industries and environments of non‐manufacturing quality‐improvement efforts. Many of the above cases, however, involve the monitoring of multiple attributes simultaneously, thus leading to the case of multinomial and multiattribute quality control methods, which are better than the simultaneous use of multiple uni‐attribute methods. In this study, an attempt to review the research previously conducted on multiattribute quality control is made in order to help the interested researchers and practitioners get informed about the references on the relevant research in this field, regarding the design, performance and applications of multiattribute control charts. Copyright © 2009 John Wiley & Sons, Ltd.
Proximal Knowledge‐based Classification
Authors: Mangasarian O. L. , Wild E. W. , Fung G. M.
Published: January 2009

Prior knowledge over general nonlinear sets is incorporated into proximal nonlinear kernel classification problems as linear equalities. The key tool in this incorporation is the conversion of general nonlinear prior knowledge implications into linear equalities in the classification variables without the need to kernelize these implications. These equalities are then included into a proximal nonlinear kernel classification formulation (G. Fung and O. L. Mangasarian, Proximal support vector machine classifiers, inProceedings KDD‐2001: Knowledge Discovery and Data Mining, F. Provost and R. Srikant (eds), San Francisco, CA, New York, Association for Computing Machinery) that is solvable as a system of linear equations. Effectiveness of the proposed formulation is demonstrated on a number of publicly available classification datasets. Nonlinear kernel classifiers for these datasets exhibit marked improvements upon the introduction of nonlinear prior knowledge compared with nonlinear kernel classifiers that do not utilize such knowledge. Copyright © 2009 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 1: 000‐000, 2009
A novel approach for chlorine determination in acidic medium by total reflection x‐ray fluorescence
Authors: Misra N. L. , Varga Imre , Dhara Sangita , Aggarwal Suresh K.
Published: January 2009

A novel approach for chlorine (Cl) determination in acidic medium using total reflection x‐ray fluorescence (TXRF) is reported. It is based on the addition of a known excess amount of AgNO3 solution to the sample containing Cl for precipitating silver chloride (AgCl). This is followed by TXRF determination of Ag in supernatant after filtering, employing Cd as an internal standard. Tungsten (W) continuum excitation at 50 kV and 38 mA was used for TXRF measurements. Ag Kα line of the analyte, Ag and Cd Kα line of the internal standard, Cd were used for such determinations of Ag. Six samples of NaCl were prepared in HNO3 medium of different molarities to obtain the Cl concentrations ranging from 1 to 60 µg/ml. The precision of such TXRF determinations of Cl in nitric acid medium samples was found to be better than 10% (1σ) and the results deviated from the expected Cl concentrations by less than 15%. An overall laboratory and reagents blank of 1.5 ± 0.5 µg/ml was obtained limiting the applicability of this approach to Cl levels of about 5 µg/ml. This can be improved by using ultra clean laboratory and high purity reagents. Copyright © 2009 John Wiley & Sons, Ltd.
Cake shortenings
Authors: Hartnett D. I.
Published: January 2009

Abstract and Summary

Triglycerides have been traditionally used in cakes to provide tenderness and grain. Specialty cake shortenings are used today to improve batter aeration, cake volume, grain, and to extend shelf life. The role of emulsifiers in providing improved shortening characteristics will be discussed. The features that will contribute to a quality cake shortening ‐ manufacturing procedures, characteristics, and specifications ‐ will be reviewed. Methods of use and handling will be related to cake quality.
Distribution of short chain n‐fatty acids in retort water from green river oil shale
Authors: Wen C. S. , Yen T. F.
Published: January 2009

Abstract and Summary

n‐Fatty acids in the range of C2 to C10 were found in retort water from a simulated in situ retorting process of Green River oil shale. The distribution of these fatty acids shows no preference between molecules of odd and even numbers of carbon atoms. A comparison with retort water from an aboveground retorting proces suggests that differences in the distribution of these acids depend largely on the technique and operating conditions employed in the retorting process.
Effects of surface active compounds on thermal denaturation of DNA
Authors: Tsujii K. , Tokiwa F.
Published: January 2009

Abstract and Summary

The interaction of surface active compounds (including N‐lauroyl amino acids) withself thymus DNA in aqueous solutions has been studied by measurements of the melting temperature of the DNA. The results suggest that the surface active nature of these additives is not the primary factor governing the interaction with DNA, but their molecular structure is very important in the interaction.
Composition of wax from seed flax straw
Authors: Tulloch A. P. , Hoffman L. L.
Published: January 2009

Abstract and Summary

Wax from leaves and stems of ripe seed flax contains hydrocarbons (14%), esters (35%), aldehydes, (12%), free acids (2%), free alcohols (17%), and unidentified material (20%). The chain length range of the hydrocarbons is C25‐C33 (major component C29); of the esters is C40‐C52 (major component C46); of the combined acids is C14‐C30 (major component C18); and of the combined and free alcohols, the aldehydes, and the free acids is C22‐C32 (major component C28).
Adaptation and Psychometric Evaluation of the Multidimensional Scale of Perceived Social Support for Arab American Adolescents
Authors: Ramaswamy Vidya , Aroian Karen J. , Templin Thomas
Published: January 2009

The multidimensional scale of perceived social support (MSPSS) was revised for Arab American adolescents (MSPSS‐AA). Items measuring social support from significant others were omitted and items measuring support from school personnel were added based on advice from cultural experts. The sample consisted of 635 Arab American young adolescents in metropolitan Detroit. Confirmatory factor analysis (CFA) supported the proposed three‐factor solution (family, friends, and school personnel). Internal consistency coefficients for the three subscales of family (α = 0.63), friends (α = 0.75), school personnel (α = 0.72) were good. As predicted, perceived support from family, friends, and school personnel were inversely related to self reports of daily hassles and internalizing behavior and positively related to assistance seeking coping, which provides evidence for construct validity. Support for discriminant validity was also demonstrated with significantly larger correlations between the MSPSS‐AA Family subscale and daily hassles specific to parents and the MSPSS‐AA Friend subscale and daily hassles specific to peers. These finding suggest that the MSPSS‐AA is reliable and valid for use with Arab‐American adolescents.
Destiny and heavenly ordinances: Two perspectives on the relationship between Heaven and human beings in Confucianism
Authors: Weixiang DING
Published: January 2009

As a pair of important categories in traditional Chinese culture, “ming 命 (destiny or decrees)” and “tian ming 天命 (heavenly ordinances)” mainly refer to the constraints placed on human beings. Both originated from “ling 令 (decrees),” which evolved from “wang ling 王令 (royal decrees)” into “tian ling 天令 (heavenly decrees),” and then became “ming” from a throne because of the decisive role of “heavenly decrees” over a throne. “Ming” and “tian ming” have different definitions: “Ming” represented the limits Heaven placed on the natural lives of human beings and was an objective force that men could not direct, but was embodied in human beings as their “destiny”; “Tian ming” reflected the moral ideals of human beings in their self-identification; It originated in man but had to be verified by Heaven, and it was therefore the true ordinance that Heaven placed on human beings. “Ming” and “tian ming” are two perspectives on the traditional relationship between Heaven and human beings, and at the same time Confucians and Daoists placed different emphasis on them.
Aesthetic judgment: The power of the mind in understanding Confucianism
Authors: Xialing XIE
Published: January 2009

Mou Zongsan incorrectly uses Kant’s practical reason to interpret Confucianism. The saying that “what is it that we have in common in our minds? It is the li 理 (principles) and the yi 义 (righteousness)” reveals how Mencius explains the origin of li and yi through a theory of common sense. In “the li and the yi please our minds, just as the flesh of beef and mutton and pork please our mouths,” “please” is used twice, proving aesthetic judgment is necessary to understanding Mencius. An analysis of Zhu Xi and Wang Yangming’s ideas will show that Confucianism should be interpreted by appealing to aesthetic judgment, and a discussion of Kant’s theory of judgment and Gadamer’s critique of Kant’s theory will support the same point. The conclusion is that Chinese moral philosophy should be interpreted through aesthetic judgment.
The Philosophies of Laozi and Zhuangzi and the Bamboo-slip Essay Hengxian
Authors: Yu QIANG
Published: January 2009

The bamboo slip essay Hengxian 恒先 is historically valuable because it serves to further the ontological understanding and comprehension of issues related to the existence of the universe from the perspective of Laozi’s Daoist thought. Hengxian explores important propositions such as how “Qi originated and activated itself” and “they came out of the same source but differed in nature” from several aspects. The idea that “Hengxian is ‘being’ without any definiteness” responds to the issue of the relationship of difference and identity of all things in the world, and thus examines the interdependent relationships between subjects and objects. It proposes that humans can further understand the existence of the universe through cognitive activities and practices such as “analysis and comparison” in which objective realities are checked. The issues discussed in Hengxian are consistent with Laozi’s Dao de jing, the works of Zhuangzi, Huangdi sijing 黄帝四经 (The Four Classics from the Emperor Yellow) and other Daoist works, and deserve significant attention.
LiMn2O4–yBr
y
Nanoparticles Synthesized by a Room Temperature Solid-State Coordination Method
Authors: Huang Yudai , Jiang Rongrong , Bao Shu-Juan , Cao Yali , Jia Dianzeng
Published: January 2009

LiMn2O4–y
Br
y
nanoparticles were synthesized successfully for the first time by a room temperature solid-state coordination method. X-ray diffractometry patterns indicated that the LiMn2O4–y
Br
y
powders were well-crystallized pure spinel phase. Transmission electron microscopy images showed that the LiMn2O4–y
Br
y
powders consisted of small and uniform nanosized particles. Synthesis conditions such as the calcination temperature and the content of Br−were investigated to optimize the ideal condition for preparing LiMn2O4–y
Br
y
with the best electrochemical performances. The optimized synthesis condition was found in this work; the calcination temperature is 800 °C and the content of Br−is 0.05. The initial discharge capacity of LiMn2O3.95Br0.05obtained from the optimized synthesis condition was 134 mAh/g, which is far higher than that of pure LiMn2O4, indicating introduction of Br−in LiMn2O4is quite effective in improving the initial discharge capacity.
The mammalian nonsense‐mediated mRNA decay pathway: To decay or not to decay! Which players make the decision?
Authors: Silva Ana Luísa , Romão Luísa
Published: January 2009

Nonsense‐mediated mRNA decay (NMD) degrades mRNAs carrying premature translation termination codons (PTCs). Although the core process and several NMD effectors are conserved among species, the involvement of a splicing‐dependent signal seems to be specific for mammalian PTC definition. Still, recent data shed new light on physical parameters and mechanistic pathways involved in NMD. Here, we examine these findings, updating the roles for potential NMD players, such as the exon junction complex and the cytoplasmic poly(A)‐binding protein 1 – the former acting as enhancer rather than an essential factor and the latter functioning as NMD repressor.
Functional characterization of the DnaK chaperone system from the archaeon Methanothermobacter thermautotrophicusΔH
Authors: Popp Simone L. , Reinstein Jochen
Published: January 2009

We characterized the biochemical and functional properties of the DnaK system from the archaeon Methanothermobacter thermautotrophicus ΔH. In contrast to the eubacterial chaperone components the archaeal Hsp70 system shows thermal transitions only slightly above the optimal environmental temperature (65 °C). Nevertheless, it prevents aggregation of luciferase in the physiological temperature range of the organism, but is also fully functional at 30 °C in luciferase refolding. Additionally, GrpE
M.th.
and DnaJ
M.th.
substitute their eubacterial counterparts whereas DnaK
M.th.
is only functional with its native cochaperones which could be attributed to a functional specialization of the eubacterial chaperones during evolution.
Conformation‐dependent single‐chain variable fragment antibodies specifically recognize beta‐amyloid oligomers
Authors: Wang Xiao-ping , Zhang Jun-hua , Wang Yu-jiong , Feng Ying , Zhang Xi , Sun Xiao-xia , Li Ji-liang , Du Xue-ting , Lambert Mary P. , Yang Shi-gao , Zhao Min , Klein William L. , Liu Rui-tian
Published: January 2009

Increasing evidence indicates that beta‐amyloid (Aβ) oligomers rather than monomers or fibrils are the major toxic agents that specifically inhibit synaptic plasticity and long‐term potentiation (LTP) in Alzheimer's disease (AD). Neutralization of Aβ oligomeric toxicity was found to reverse memory deficits. Here, we report four single‐chain variable fragment (scFv) antibodies isolated from the naive human scFv library by phage display that specifically recognized Aβ oligomers but not monomers and fibrils. These conformation‐dependent scFv antibodies inhibit both Aβ fibrillation and cytotoxicity and bind to the same type of eptitope displayed on the Aβ oligomers. Such scFv antibodies specifically targeting toxic Aβ oligomers may have potential therapeutic and diagnostic applications for AD.
Early maternal deprivation in rats induces gender‐dependent effects on developing hippocampal and cerebellar cells
Authors: Llorente Ricardo , Gallardo Meritxell López , Berzal Alvaro Llorente , Prada Carmen , Garcia‐Segura Luis Miguel , Viveros María‐Paz
Published: January 2009

Adult animals submitted to a single prolonged episode of maternal deprivation [24 h, postnatal day 9–10] show behavioral alterations that resemble specific symptoms of schizophrenia. According to the neurodevelopmental theory, these behavioral deficits might be mediated by detrimental neurodevelopmental processes that might be associated, at least partially, with stress‐induced corticosterone responses. In order to address this hypothesis, we have focused on the hippocampus and cerebellar cortex, two brain regions that show high density of glucocorticoid receptors, and analyzed possible neuronal and glial alterations by immunohistochemical techniques. To evaluate the presence of degenerated neurons we used Fluoro‐Jade‐C (FJ‐C) staining and for the study of astrocytes we employed glial fibrillary acidic protein (GFAP). Within control animals, females showed significantly more GFAP positive cells than males and a trend towards more FJ‐C positive cells. Maternal deprivation induced neuronal degeneration and astroglial changes in the hippocampus and cerebellar cortex of neonatal rats that, in general, were more marked in males. This differential effect may be attributable to a greater vulnerability of males to this kind of early environmental insult and/or to sex‐dependent differences in the onset and/or progression of the effects. The present experimental procedure may be instrumental in elucidating sex‐dependent mechanisms of neurodevelopmental psychiatric disorders with a basis in early environmental insults.
Mitochondrial alterations in aging rat brain: effective role of (−)‐epigallo catechin gallate
Authors: Srividhya Ravichandran , Zarkovic Kamelija , Stroser Marina , Waeg Georg , Zarkovic Neven , Kalaiselvi Periandavan
Published: January 2009

Aging is a multi‐factorial process which involves deprivation in body's metabolism. Brain mitochondria are prone to oxidative damage owing to their high metabolic rate. The decline in antioxidant system during aging augments the neuronal damage to mitochondrial components like antioxidant system, Kreb's cycle enzymes and electron transport chain complexes. Since brain is an organ rich in fatty acids, lipid peroxidation products like hydroxynonenal are predominant. Those lipid peroxidation products conjugate with amino acids to form adducts which alter their structural and functional properties. Epigallo catechin gallate is a potent antioxidant which is rich in green tea extract. This study elucidated the antioxidant potential of epigallo catechin gallate to counteract the mitochondrial oxidative damage in brain. The study comprised of young (3–4 months old; 150 ± 20 g) and aged (above 24 months; 420 ± 20 g) male albino rats of Wistar strain in Groups I and II. Groups III and IV comprised of young and aged rats supplemented with epigallo catechin gallate (2 mg/kg body weight) for 30 days. Antioxidants, Kreb's cycle enzymes and electron transport chain complexes were assayed in the mitochondrial fraction. Hydroxynonenal expression was carried out using immunohistochemical analysis. Epigallo catechin gallate supplementation decreased the expression of hydroxynonenal in aged brain, up‐regulated the antioxidant system and augmented the activities of Kreb's cycle enzymes and electron transport chain complexes in aged brain mitochondria thus proving its antioxidant potential at the level of mitochondria.
Analyzing haplodiploid inheritance of insecticide resistance in whitefly biotypes
Authors: Crowder D.W. , Horowitz A.R. , Tabashnik B.E. , Dennehy T.J. , Denholm I. , Gorman K. , Carrière Y.
Published: January 2009

We developed new methods for analyzing inheritance of insecticide resistance in haplodiploid arthropods and applied them to elucidate resistance of the whiteflyBemisia tabaci(Gennadius) to an insect growth regulator, pyriproxyfen. Two invasive biotypes of this devastating crop pest, the B biotype in Arizona and the Q biotype in Israel, have evolved resistance to pyriproxyfen. Here, we incorporated data from laboratory bioassays and crossing procedures exploiting haplodiploidy into statistical and analytical models to estimate the number of loci affecting pyriproxyfen resistance in strains of both biotypes. In tests with models of one to ten loci, the best fit between expected and observed mortality occurred with a two-locus model for the B biotype strain (QC-02) and for one- and two-locus models for the Q biotype strain (Pyri-R). The estimated minimum number of loci affecting resistance was 1.6 for the B biotype strain and 1.0 for the Q biotype strain. The methods used here can be applied to insecticide resistance and other traits in haplodiploid arthropods.
Investigating the diet of the omnivorous mirid Dicyphus hesperus using stable isotopes
Authors: Bennett J.A. , Gillespie D.R. , VanLaerhoven S.L.
Published: January 2009

Omnivory involves numerous feeding relationships and a complex web of interactions. When using omnivores in biocontrol, these interactions need to be understood to maximize feeding on the target species and minimize non-target interactions. Dicyphus hesperus is used along with Encarsia formosa for biocontrol of whiteflies in greenhouse tomato crops. Dicyphus hesperus is a generalist omnivore which feeds on all components of the system. To quantify these interactions, stable isotope analysis was used to identify trophic position with nitrogen isotopes (δ15N) and plant sources with carbon isotopes (δ13C). Feeding trials were used to establish baseline isotopic data for D. hesperus and their diet, including Verbascum thapsus, an alternative plant food. Cage trials were used to monitor population abundances and the isotopic signature of D. hesperus. In feeding trials, D. hesperus were enriched relative to their food, suggesting an elevated trophic position. However, large amounts of isotopic variation were found within all diet components, with only V. thapsus exhibiting a distinct signature. In cage trials, the average δ15N and δ13C of the omnivore declined over time, coinciding with declines in total available prey, though it may be confounded by changes in temperature. The range of δ13C, but not the range of δ15N, also declined over time. This suggests a change in the plant source within the diet, but also some unquantified variability within the population. We suggest that diet variability exists within D. hesperus populations, declining as prey become less abundant.
The first account of the mating disruption technique for the control of California red scale, Aonidiella aurantii Maskell (Homoptera: Diaspididae) using new biodegradable dispensers
Authors: Vacas S. , Alfaro C. , Navarro-Llopis V. , Primo J.
Published: January 2009

Semiochemical-based pest management programs have been increasingly used to provide environmentally friendly methods for the control of major insect pests. The efficacy of the mating disruption technique has been demonstrated for several moth pests. Unfortunately, not many experiments on mating disruption to control diaspididae species have been documented. In this work, biodegradable dispensers for mating disruption with increasing pheromone loads were used in order to study the potential of this technique for the control of Aonidiella aurantii Maskell. Field trial results demonstrated that dispensers loaded with 50 mg (a.i.) (20 g ha−1) and 100 mg (a.i.) (40 g ha−1) of sex pheromone were the most suitable, achieving significant reductions in male catches, compared to an untreated plot. In treated plots, virtually a 70% reduction in damage to fruit was recorded. Pheromone release profiles of all the dispensers were also studied under field conditions. We found that emission values >250 μg day−1 were the most suitable. This study suggests a new biodegradable dispenser capable of interfering with normal A. aurantii chemical communication. The use of mating disruption as a control method against A. aurantii is discussed.
Heligmosomoides polygyrusreduces infestation ofIxodes ricinusin free-living yellow-necked mice,Apodemus flavicollis
Authors: FERRARI N. , CATTADORI I. M. , RIZZOLI A. , HUDSON P. J.
Published: January 2009

Free-living animals are usually inhabited by a community of parasitic species that can interact with each other and alter both host susceptibility and parasite transmission. In this study we tested the prediction that an increase in the gastrointestinal nematodeHeligmosomoides polygyruswould increase the infestation of the tickIxodes ricinus, in free-living yellow-necked mice,Apodemus flavicollis. An extensive cross-sectional trapping survey identified a negative relationship betweenH. polygyrusandI. ricinuscounter to the prediction. An experimental reduction of the nematode infection through anthelmintic treatment resulted in an increase in tick infestation, suggesting that this negative association was one of cause and effect. Host characteristics (breeding condition and age) and habitat variables also contributed to affect tick infestation. While these results were counter to the prediction, they still support the hypothesis that interactions between parasite species can shape parasite community dynamics in natural systems. Laboratory models may act differently from natural populations and the mechanism generating the negative association is discussed.
The influence of clonal diversity and intensity-dependence on trematode infections in an amphipod
Authors: KEENEY D. B. , BRYAN-WALKER K. , KHAN N. , KING T. M. , POULIN R.
Published: January 2009

Individual animals are often infected not only by different parasite species, but also by multiple genotypes of the same parasite species. Genetic relatedness among parasites sharing a host is expected to modulate their strategies of resource exploitation, growth and virulence. We experimentally examined the effects that genetic diversity and infection intensity had on host mortality, infectivity and growth of the marine trematodeMaritrema novaezealandensisin amphipod hosts. The presence of 2 versus 1 parasite genotype during infection did not influence subsequent host mortality, had different effects on infectivity among genotypes and did not influence growth or variation in parasite growth. Density-dependent growth reductions revealed that the number of parasites infecting a host was more important than their genetic relatedness. Temperature, host size, and host sex influenced the degree to which density-dependent factors affected parasite growth. Our results suggest that the effects of parasite relatedness vary among parasite genotypes in this trematode species, and reveal that many factors play an important role during parasite development and transmission.
A novel phylogeny for the genus Echinococcus, based on nuclear data, challenges relationships based on mitochondrial evidence
Authors: SAARMA U. , JÕGISALU I. , MOKS E. , VARCASIA A. , LAVIKAINEN A. , OKSANEN A. , SIMSEK S. , ANDRESIUK V. , DENEGRI G. , GONZÁLEZ L. M. , FERRER E. , GÁRATE T. , RINALDI L. , MARAVILLA P.
Published: January 2009

The taxonomic status of Echinococcus, an important zoonotic cestode genus, has remained controversial, despite numerous attempts to revise it. Although mitochondrial DNA (mtDNA) has been the source of markers of choice for reconstructing the phylogeny of the genus, results derived from mtDNA have led to significant inconsistencies with earlier species classifications based on phenotypic analysis. Here, we used nuclear DNA markers to test the phylogenic relationships of members of the genus Echinococcus. The analysis of sequence data for 5 nuclear genes revealed a significantly different phylogeny for Echinococcus from that proposed on the basis of mitochondrial DNA sequence data, but was in agreement with earlier species classifications. The most notable results from the nuclear phylogeny were (1) E. multilocularis was placed as basal taxon, (2) all genotypes of Echinococcus granulosus grouped as a monophyletic entity, and (3) genotypes G8 and G10 clustered together. We conclude that the analysis of nuclear DNA data provides a more reliable means of inferring phylogenetic relationships within Echinococcus than mtDNA and suggest that mtDNA should not be used as the sole source of markers in future studies where the goal is to reconstruct a phylogeny that does not only reflect a maternal lineage, but aims to describe the evolutionary history at species level or higher.
Elevated levels of urinary hydrogen peroxide, advanced oxidative protein product (AOPP) and malondialdehyde in humans infected with intestinal parasites
Authors: CHANDRAMATHI S. , SURESH K. , ANITA Z. B. , KUPPUSAMY U. R.
Published: January 2009

Oxidative stress has been implicated as an important pathogenic factor in the pathophysiology of various life-threatening diseases such as cancer, cardiovascular diseases and diabetes. It occurs when the production of free radicals (generated during aerobic metabolism, inflammation, and infections) overcome the antioxidant defences in the body. Although previous studies have implied that oxidative stress is present in serum of patients with parasitic infection there have been no studies confirming oxidative stress levels in the Malaysian population infected with intestinal parasites. Three biochemical assays namely hydrogen peroxide (H2O2), lipid peroxidation (LP) and advanced oxidative protein product (AOPP) assays were carried out to measure oxidative stress levels in the urine of human subjects whose stools were infected with parasites such asBlastocystis hominis,Ascaris,Trichuris, hookworm and microsporidia. The levels of H2O2, AOPP and LP were significantly higher (P<0·001,P<0·05 andP<0·05 respectively) in the parasite-infected subjects (n=75) compared to the controls (n=95). In conclusion, the study provides evidence that oxidative stress is elevated in humans infected by intestinal parasites. This study may influence future researchers to consider free radical-related pathways to be a target in the interventions of new drugs against parasitic infection and related diseases.
A Number Problem
Authors: Wilson N. Y.
Published: January 2009

A and B study an array of counters, placed in straight lines on a table, in separated groups (e.g. 28, 53, 1, 16). The counters are to be removed under the following conditions :–

Each “player” may take away

(1) one counter from anywhere (e.g. 27, 53, 1, 16) or (28, 20, 32, 1, 16) etc.

or (2) three counters from anywhere (e.g. 28, 53, 14) or (27, 52, 1, 15) or (28, 25, 17, 6, 2, 1, 16) etc.

or (3) two adjacent counters from one group (e.g. 28, 51, 1, 16) or (28, 53, 1, 8, 6) etc.
An Alternative Proof of a Theorem on the Lebesgue Integral
Authors: Josephson B. D.
Published: January 2009

The theorem concerned is the following: iff is continuous in [a, b], and f exists and is finite except at an enumerable set of points and Lebesgue integrable in [a, b], then
Plane Collineations
Authors: Hartley E. M.
Published: January 2009

If in a complex projective plane a point P, with coordinate vector x, corresponds to a point p*, with coordinate vector x*, under a non-singular collineation, then

x* = Ax

where A is a non-singular 3×3 matrix, the coordinates and the elements of A being complex numbers.
Linear Ordinary Differential Equations with Constant Coefficients: Identification of Boole's Integral with that of Cauchy
Authors: Parsons D. H.
Published: January 2009

We consider an equation with constant coefficients

where a≠0 and f(x) is continuous in a suitable interval. Suppose that the symbolic polynomial P(D) has been fully decomposed into its (real or complex) linear factors, so that the equation may be written

where b1, …, bq are distinct, and m1+…+mq = n. The Complementary Function being now known, we may write down a particular integral of (1) by Cauchy's method.
Inertia Invariants of a Set of Particles
Authors: Slater N. B.
Published: January 2009

The formal object of this note is the calculation of the principal moments of inertia of a set of particles at their mass centre, in terms of their mutual distances; he calculation brings in some identities which although simple may be in part novel.
A New Look for Hamiltonian Dynamics
Authors: Kilmister C. W.
Published: January 2009

It seems a pity that Hamiltonian dynamics—contact transformations and so on—is regarded as a fearsome subject, too time-consuming to teach to most students; for it is the one branch of dynamics to point a way to new developments in this century. Moreover the basic ideas are extremely simple, but presented in an unfortunate way in all the text-books.
Lithospheric electrical imaging of the Deccan trap covered region of western India
Authors: Patro Prasanta K. , Sarma S. V. S.
Published: January 2009

We present here the results of magnetotelluric (MT) studies carried out along a 330 km long NE‐SW trending traverse from Daulatabad at the northeastern end to Koyna on the southwestern end across the Deccan volcanic province (DVP) in western India. The 2‐D MT modeling results obtained along this traverse together with those from other MT traverses in this area are examined and integrated with the results from deep seismic sounding, 3‐D teleseismic tomography, and heat flow studies. The deep geoelectric section as deduced from MT models point out to a two layered lithospheric mantle structures with an upper very high‐resistive layer (several thousands of ohm m) and a bottom relatively conductive one (a few tens of ohm m to a few hundred ohm m). The lithospheric electrical structure is inferred to be linked to compositional changes associated with a depleted lithospheric upper mantle in the Dharwar craton. An impressive feature that the study has brought out is the presence of a well‐defined lithospheric upper mantle conductor in the depth range of 80–120 km limited to the middle segment of the MT traverse from Sangole to Partur over the DVP. The electrical characterization of the region including the presence of upper mantle conductor shows close similarities with that of other similar cratonic regions like the Slave and Superior cratons in northwestern Canada.
Characterizing the South Atlantic Bight seasonal variability and cold‐water event in 2003 using a daily cloud‐free SST and chlorophyll analysis
Authors: Miles Travis N. , He Ruoying , Li Mingkui
Published: January 2009

Concurrent MODIS sea surface temperature (SST) and chlorophyll‐a (Chl‐a) data are used with a new technique: Data Interpolating Empirical Orthogonal Function (DINEOF) method to produce daily, 4‐km, cloud‐free SST and Chl‐a analyses for the South Atlantic Bight in 2003. Comparisons between SST analysis and in situ buoy temperature demonstrate the utility of DINEOF. To quantify linkages between surface wind, SST, and Chl‐a variations, Empirical Orthogonal Function (EOF) analysis is applied to North American Regional Reanalysis winds, and cloud‐free DINEOF SST and Chl‐a analyses. Wind EOF modes highlight upwelling winds from June to September. While the first SST mode represents seasonal heat flux variations, the second SST mode shows a direct response to upwelling winds with an abrupt drop in SST. The top two Chl‐a EOF modes show less connection with wind. More subsurface Chl‐a and nutrient observations are needed to quantify its relation with surface wind.