bluuebunny/crossref_metadata_2025 huggingface dataset:
Insights into the mechanistic photodissociation of methyl formate
Authors: Cui Ganglong , Zhang Feng , Fang Weihai
Published: January 2010

In this work, we studied the photodissociation dynamics of methyl formate (CH3OC(O)H) using state-of-the-art multireference configuration interaction with single and double excitation and the complete active space self-consistent field methods. It was found that the direct α-CO bond cleavage in the first excited singlet state (S1) is the dominant dissociation channel, consistent with the recent experiment [S. H. Lee, J. Chem. Phys. 129, 194304 (2008)]. This cleavage mechanism is different from that for aldehydes/ketones where it occurs in the lowest triplet state (T1) as a result of the S1→T1 intersystem crossing. On the basis of comparison to the α-bond fission in the asymmetrically substituted aliphatic carbonyl compounds studied previously, we suggest the photolytic reaction of CH3OC(O)H as a special type of Norrish type I reaction.
Peroxidase biocathodes for a biofuel cell development
Authors: Gomez Celso , Shipovskov Stepan , Ferapontova Elena E.
Published: January 2010

In terms of sustainable energy production, enzymatic biofuel cells are attractive for a number of special applications, such as disposable implantable power suppliers for medical sensor-transmitters and drug delivery/activator systems and self-powered enzyme-based biosensors; they offer practical advantages of using abundant organic raw materials as biofuels for clean and sustainable energy production. In this paper we discuss what power densities can be expected from enzymatic biofuel cells and what are the possibilities and limits for their optimization. As example, in this work, the designed hybrid biofuel cell formed by the battery type Zn anode and the biocathode, comprising horseradish peroxidase (HRP) immobilized on graphite and utilizing H2O2 as an oxidizer, is considered. The cell yields the open circuit voltage Voc of 1.68 and 1.57 V and the short-circuit current density isc of 800 μA cm−2 at pH 6 and 580 μA cm−2 at pH 7.45 in quiescent solutions. The biofuel cell operated at 1.5 V for 6 days; the maximum power density of the cell was 98 μW cm−2 at 0.6 V and pH 6. When coupled to the H2O2-producing glucose oxidizing enzymes (glucose oxidase or pyranose oxidase), the HRP biocathode was functional in the presence of glucose with no essential loss in I-V characteristics. The biocathode performance and possibilities for its optimization were studied and compared with the hitherto existing biocathodes and biofuel cell designs.
The improved performance of dye sensitized solar cells by bifunctional aminosilane modified dye sensitized photoanode
Authors: Zhang Jing , Yang Guangtao , Sun Qiang , Zheng Jun , Wang Peiqing , Zhu Yuejin , Zhao Xingzhong
Published: January 2010

The dye sensitized photoanode is modified by the bifunctional 3-aminopropyltriethoxysilane (APTS). The attenuated total reflection–Fourier transform infrared spectroscopy, the UV-IR spectroscopy, the dye adsorption amount, and the electrochemical impedance spectroscopy were carried out to examine the modification effect. The experiments indicated that the APTS with amino endgroup and triethoxysilane group deprotonated the surface of the dye sensitized photoanode and formed a SiOSi network at the dye sensitized photoanode/redox electrolyte interface. The treading time and concentration of APTS ethanol solution to the performance of dye sensitized solar cells (DSSCs) were checked. The Voc was improved by APTS ethanol solution modification, which was ascribed to the negative movement of the conduction band potential and reduced electron recombination from the TiO2 conduction band to the redox electrolyte. Jsc was impaired by large amounts of APTS modification, which indicated that the excessive APTS modification blocked the charge transport in the DSSC. With moderate concentration of APTS ethanol solution (0.05 mM) modification, the performance of the DSSC was optimized to 7.04% [Jsc=14.8 mA cm−2, Voc=0.666 V, and fill factor (FF)=0.642] compared with the performance of 5.23% (Jsc=11.84 mA cm−2, Voc=0.595 V, and FF=0.67) of the original DSSC at 0.9 sun and AM 1.5.
Hyperpolarizabilities of the methanol molecule: A CCSD calculation including vibrational corrections
Authors: Dutra Adriano S. , Castro Marcos A. , Fonseca Tertius L. , Fileti Eudes E. , Canuto Sylvio
Published: January 2010

In this work we present the results for hyperpolarizabilities of the methanol molecule including vibrational corrections and electron correlation effects at the CCSD level. Comparisons to random phase approximation results previously reported show that the electron correlation is in general important for both electronic contribution and vibrational corrections. The role played by the anharmonicities on the calculations of the vibrational corrections has also been analyzed and the obtained results indicate that the anharmonic terms are important for the dc-Pockels and dc-Kerr effects. For the other nonlinear optical properties studied the double-harmonic approximation is found to be suitable. Comparison to available experimental result in gas phase for the dc-second harmonic generation second hyperpolarizability shows a very good agreement with the electronic contribution calculated here while our total value is 14% larger than the experimental value.
The circadian output gene
takeout
is regulated by
Pdp1ε
Authors: Benito Juliana , Hoxha Valbona , Lama Chamala , Lazareva Anna A. , Ferveur Jean-François , Hardin Paul E. , Dauwalder Brigitte
Published: January 2010

The circadian clock controls many circadian outputs. Although a large number of transcripts are affected by the circadian oscillator, very little is known about their regulation and function. We show here that the
Drosophila takeout
gene, one of the output genes of the circadian oscillator, is regulated similarly to the circadian clock genes
Clock
(
Clk
) and
cry
.
takeout
RNA levels are at constant high levels in

Clk
JRK

mutants. The circadian transcription factor
PAR domain protein 1
(
Pdp1ε
) is a transcription factor that had previously been postulated to control clock output genes, particularly genes regulated similarly to
Clk
. In agreement with this, we show here that
Pdp1ε
is a regulator of
takeout
. Takeout levels are low in flies with reduced
Pdp1ε
and high in flies with increased amounts of
Pdp1ε
. Furthermore, flies with reduced or elevated
Pdp1ε
levels in the fat body display courtship defects, identifying
Pdp1ε
as an important transcriptional regulator in that tissue.
Molecular keys of the tropism of integration of the cholera toxin phage
Authors: Das Bhabatosh , Bischerour Julien , Val Marie-Eve , Barre François-Xavier
Published: January 2010

Cholera toxin is encoded in the genome of CTXφ, a lysogenic filamentous phage of
Vibrio cholerae.
CTXφ variants contribute to the genetic diversity of cholera epidemic strains. It has been shown that the El Tor variant of CTXφ hijacks XerC and XerD, two host-encoded tyrosine recombinases that normally function to resolve chromosome dimers, to integrate at
dif
1, the dimer resolution site of the larger of the two
V. cholerae
chromosomes. However, the exact mechanism of integration of CTXφ and the rules governing its integration remained puzzling, with phage variants integrated at either or both dimer resolution sites of the two
V. cholerae
chromosomes. We designed a genetic system to determine experimentally the tropism of integration of CTXφ and thus define rules of compatibility between phage variants and dimer resolution sites. We then showed in vitro how these rules are explained by the direct integration of the single-stranded phage genome into the double-stranded bacterial genome. Finally, we showed how the evolution of phage attachment and chromosome dimer resolution sites contributes to the generation of genetic diversity among cholera epidemic strains.
Electron traps and their effect on the surface chemistry of TiO
2
(110)
Authors: Papageorgiou Anthoula C. , Beglitis Nikolaos S. , Pang Chi L. , Teobaldi Gilberto , Cabailh Gregory , Chen Qiao , Fisher Andrew J. , Hofer Werner A. , Thornton Geoff
Published: January 2010

Oxygen vacancies on metal oxide surfaces have long been thought to play a key role in the surface chemistry. Such processes have been directly visualized in the case of the model photocatalyst surface TiO
2
(110) in reactions with water and molecular oxygen. These vacancies have been assumed to be neutral in calculations of the surface properties. However, by comparing experimental and simulated scanning tunneling microscopy images and spectra, we show that oxygen vacancies act as trapping centers and are negatively charged. We demonstrate that charging the defect significantly affects the reactivity by following the reaction of molecular oxygen with surface hydroxyl formed by water dissociation at the vacancies. Calculations with electronically charged hydroxyl favor a condensation reaction forming water and surface oxygen adatoms, in line with experimental observations. This contrasts with simulations using neutral hydroxyl where hydrogen peroxide is found to be the most stable product.
Cardioprotective effects of growth hormone-releasing hormone agonist after myocardial infarction
Authors: Kanashiro-Takeuchi Rosemeire M. , Tziomalos Konstantinos , Takeuchi Lauro M. , Treuer Adriana V. , Lamirault Guillaume , Dulce Raul , Hurtado Michael , Song Yun , Block Norman L. , Rick Ferenc , Klukovits Anna , Hu Qinghua , Varga Jozsef L. , Schally Andrew V. , Hare Joshua M.
Published: January 2010

Whether the growth hormone (GH)/insulin-like growth factor 1(IGF-1) axis exerts cardioprotective effects remains controversial; and the underlying mechanism(s) for such actions are unclear. Here we tested the hypothesis that growth hormone-releasing hormone (GHRH) directly activates cellular reparative mechanisms within the injured heart, in a GH/IGF-1 independent fashion. After experimental myocardial infarction (MI), rats were randomly assigned to receive, during a 4-week period, either placebo (n = 14), rat recombinant GH (n = 8) or JI-38 (n = 8; 50 µg/kg per day), a potent GHRH agonist. JI-38 did not elevate serum levels of GH or IGF-1, but it markedly attenuated the degree of cardiac functional decline and remodeling after injury. In contrast, GH administration markedly elevated body weight, heart weight, and circulating GH and IGF-1, but it did not offset the decline in cardiac structure and function. Whereas both JI-38 and GH augmented levels of cardiac precursor cell proliferation, only JI-38 increased antiapoptotic gene expression. The receptor for GHRH was detectable on myocytes, supporting direct activation of cardiac signal transduction. Collectively, these findings demonstrate that within the heart, GHRH agonists can activate cardiac repair after MI, suggesting the existence of a potential signaling pathway based on GHRH in the heart. The phenotypic profile of the response to a potent GHRH agonist has therapeutic implications.
Mutant EGFR is required for maintenance of glioma growth in vivo, and its ablation leads to escape from receptor dependence
Authors: Mukasa Akitake , Wykosky Jill , Ligon Keith L. , Chin Lynda , Cavenee Webster K. , Furnari Frank
Published: January 2010

Epidermal growth factor receptor (EGFR) gene amplification is the most common genetic alteration in high-grade glioma, and ≈50% of EGFR-amplified tumors also harbor a constitutively active mutant form of the receptor, ΔEGFR. Although ΔEGFR greatly enhances tumor growth and is thus an attractive target for anti-glioma therapies, recent clinical experiences with EGFR kinase inhibitors have been disappointing, because resistance is common and tumors eventually recur. Interestingly, it has not been established whether ΔEGFR is required for maintenance of glioma growth in vivo, and, by extension, if it truly represents a rational therapeutic target. Here, we demonstrate that in vivo silencing of regulatable ΔEGFR with doxycycline attenuates glioma growth and, therefore, that it is crucial for maintenance of enhanced tumorigenicity. Similar to the clinical experience, tumors eventually regained aggressive growth after a period of stasis, but interestingly, without re-expression of ΔEGFR. To determine how tumors acquired this ability, we found that a unique gene,KLHDC8, herein referred to asSΔE(Substitute for ΔEGFR Expression)-1, is highly expressed in these tumors, which have escaped dependence on ΔEGFR. SΔE-1 is also expressed in human gliomas and knockdown of its expression in ΔEGFR-independent “escaper” tumors suppressed tumor growth. Taken together, we conclude that ΔEGFR is required for both glioma establishment and maintenance, and that gliomas undergo selective pressure in vivo to employ alternative compensatory pathways to maintain aggressiveness in the event of EGFR silencing. Such alternative pathways function as substitutes for ΔEGFR signaling and should therefore be considered as potential targets for additional therapy.
bZIP transcription factor
zip-2
mediates an early response to
Pseudomonas aeruginosa
infection in
Caenorhabditis elegans
Authors: Estes Kathleen A. , Dunbar Tiffany L. , Powell Jennifer R. , Ausubel Frederick M. , Troemel Emily R.
Published: January 2010

Very little is known about how animals discriminate pathogens from innocuous microbes. To address this question, we examined infection-response gene induction in the nematode
Caenorhabditis elegans
. We focused on genes that are induced in
C. elegans
by infection with the bacterial pathogen
Pseudomonas aeruginosa,
but are not induced by an isogenic attenuated
gacA
mutant. Most of these genes are induced independently of known immunity pathways. We generated a GFP reporter for one of these genes, infection response gene 1 (
irg-1
), which is induced strongly by wild-type
P. aeruginosa
strain PA14, but not by other
C. elegans
pathogens or by other wild-type
P. aeruginosa
strains that are weakly pathogenic to
C. elegans
. To identify components of the pathway that induces
irg-1
in response to infection, we performed an RNA interference screen of
C. elegans
transcription factors. This screen identified
zip-2
, a bZIP transcription factor that is required for inducing
irg-1
, as well as several other genes, and is important for defense against infection by
P. aeruginosa
. These data indicate that
zip-2
is part of a specialized pathogen response pathway that is induced by virulent strains of
P. aeruginosa
and provides defense against this pathogen.
Identification and functional characterization of paxillin as a target of protein tyrosine phosphatase receptor T
Authors: Zhao Yiqing , Zhang Xiaodong , Guda Kishore , Lawrence Earl , Sun Qun , Watanabe Toshio , Iwakura Yoichiro , Asano Masahide , Wei Lanlan , Yang Zhirong , Zheng Weiping , Dawson Dawn , Willis Joseph , Markowitz Sanford D. , Satake Masanobu , Wang Zhenghe
Published: January 2010

Protein tyrosine phosphatase receptor-type T (PTPRT) is the most frequently mutated tyrosine phosphatase in human cancers. However, the cell signaling pathways regulated by PTPRT largely remain to be elucidated. Here, we show that paxillin is a direct substrate of PTPRT and that PTPRT specifically regulates paxillin phosphorylation at tyrosine residue 88 (Y88) in colorectal cancer (CRC) cells. We engineered CRC cells homozygous for a paxillin Y88F knock-in mutant and found that these cells exhibit significantly reduced cell migration and impaired anchorage-independent growth, fail to form xenograft tumors in nude mice, and have decreased phosphorylation of p130CAS, SHP2, and AKT. PTPRT knockout mice that we generated exhibit increased levels of colonic paxillin phosphorylation at residue Y88 and are highly susceptible to carcinogen azoxymethane-induced colon tumor, providing critical in vivo evidence that PTPRT normally functions as a tumor suppressor. Moreover, similarly increased paxillin pY88 is also found as a common feature of human colon cancers. These studies reveal an important signaling pathway that plays a critical role in colorectal tumorigenesis.
Middle Easts, old and new
Authors: Salamé Ghassan
Published: January 2010

This article is the text of an address given by Ghassan Salamé at the ‘Oil and Money’ Conference convened in London, UK, on 21 October 2009. In it, the author deals with what the ambiguous, amorphous, elastic and politically expedient term ‘Middle East’ has connoted historically and what it may or may not denote in political formulations of a given moment. In particular, American, European, Turkish, Iranian, Israeli and Arab views – and the serious implications of these – are examined with superb economy of style. Whether as part of the USdelimited region of the Middle East and North Africa (MENA) or whether as affiliated to the European Union via a Mediterranean Union based on trade relations, the exclusion or inclusion in the Middle East is not a simple matter where regional players such as Iran and Turkey have historical extraterritorial ambitions which would, yet again, appear to be coming to the fore – even when such may threaten internal balances. The author argues that Israel’s position is increasingly problematic due not only to Palestinian demographics, but also to its recent experience against Hezbollah which has mastered asymmetrical warfare at a time when the ability of the United States to defend its primary ally in the region has been cast into doubt. The states of the Arab World have proved ineffectual and certain of them are looking to ‘escape’ from the Middle East into Africa (Libya) or looking to formulate a new regional constellation in which Turkey and Iran will play leading roles (Syria).
The Arab world amidst the global financial crisis of 2008–2009
Authors: Sharma Shalendra D.
Published: January 2010

When the problems in the United States housing sector mushroomed into a global financial crisis by September 2008, it was assumed that Arab countries would remain immune: the oil-rich Gulf Cooperation Council (GCC) countries because of their massive financial reserves, and the resource-poor countries because of their limited linkages to the global economic system – in particular, the global financial markets. However, this assumption has proven to be false. The US subprime mortgage collapse not only pushed the advanced economies into recession, but also it shattered global economic confidence, resulting in a massive financial contagion around the world. What explains the Arab World’s vulnerability to the crisis? How has the crisis impacted both the resource rich and the resource poor? How have Arab countries responded to the crisis, and what must they do to insulate their economies better from the vagaries of global financial markets? This paper addresses these questions.
Hydrogen-induced cracking and hydrogen embrittlement of Ni2MnGa FSMAs
Authors: Shen Liancheng , Su Yanjing , He Jianying , Chu Wuyang , Qiao Lijie
Published: January 2010

Hydrogen-induced cracking and hydrogen embrittlement of Ni50Mn30Ga20 ferromagnetic shape memory alloys (FSMAs) were studied through indentation and tension experiments supplemented with in situ observation. The results showed that for Ni50Mn30Ga20 FSMAs, hydrogen-induced cracking could occur with the residual stress caused by indentation during dynamic hydrogen charging. Hydrogen-induced cracking was initiated and propagated during dynamic hydrogen charging in the pre-cracked specimens under constant deflection. The fracture toughness K
IC decreased from 1.9 MPa m1/2 for the uncharged specimens to 0.4 MPa m1/2 for the samples charged with hydrogen. The possible mechanism of hydrogen-induced cracking and hydrogen embrittlement for Ni50Mn30Ga20 FSMAs is due to diffusible hydrogen decreasing the efficient surface energy.
The effect of surface domain structure on low-field microwave absorption of magnetic microwires
Authors: Buznikov N A
Published: January 2010

A model to describe the low-field microwave absorption of soft magnetic microwires is proposed. The field distributions inside a microwire and microwave absorption are found by means of a solution of Maxwell equations and the Landau–Lifshitz–Gilbert equation. It is shown that the microwave absorption field dependence is sensitive to a domain structure in a microwire surface region. The results obtained are applicable for both the amorphous microwires and the microwires consisting of a conducting nonmagnetic core and a soft magnetic shell.
Ferromagnetic resonance linewidth mechanisms in annealed CoFeSiB glass-covered microwires
Authors: Sossmeier K D , Beck F , Gomes R C , Schelp L F , Carara M
Published: January 2010

Magnetic relaxation of CoFeSiB glass-covered microwire under applied stress and Joule heating annealing was investigated by ferromagnetic resonance (FMR) linewidth experiments. We were able to identify the main damping mechanisms and to quantify these damping terms, showing the effect of annealing and applied stress on the damping terms. The study has shown that there are three main damping mechanisms responsible for the FMR linewidth: the Gilbert damping parameter, a damping mechanism due to anisotropy dispersions and two-magnon scattering. The Gilbert damping parameter is constant and not influenced by annealing and stress. The FMR linewidth is very sensitive to anisotropy dispersions and this mechanism has a considerable contribution to magnetic relaxation. The two-magnon scattering is an assignment of the inhomogeneities present in the samples.
On the electronic origin of the inverse magnetocaloric effect in Ni–Co–Mn–In Heusler alloys
Authors: Vasiliev A N , Heczko O , Volkova O S , Vasilchikova T N , Voloshok T N , Klimov K V , Ito W , Kainuma R , Ishida K , Oikawa K , Fähler S
Published: January 2010

In order to understand the electronic origin of the inverse magnetocaloric effect observed in a Ni–Co–Mn–In system we used a combination of indirect experimental probes as magnetization, resistivity and specific heat. The findings are compared with the band structure of isostructural Heusler alloys such as Ni–Mn–Ga. We suggest that the inverse magnetocaloric effect in Ni–Co–Mn–In originates from the high density of states close to Fermi energy. Within the austenite state this causes ferromagnetic band splitting. The structural change to the martensite allows an alternative way to reduce the high density of states at lower temperatures, which does not require band splitting and thus does not support ferromagnetic order.
Composition of a plasma generated from N2–O2 by an Ar ion jet in a low pressure reactor
Authors: Kutasi Kinga
Published: January 2010

The expansion of a supersonic Ar+ ion jet in a low pressure (0.2 Torr) reactor filled with N2 and O2 has been investigated by means of hydrodynamic modelling. The gas velocity fields and the gas temperature distribution in the three-dimensional reactor have been determined. The formation of different species through the molecular kinetics triggered by the collision of Ar+ ions with N2 and O2 molecules has been studied. We have investigated the effect of the ions velocity and molecular gas flow rates on the gas temperature and species density distributions. We have shown that the main difference between this system and an N2–O2 post-discharge lies in the dissociation degrees of N2 and O2. While in an N2–O2 post-discharge the N2 dissociation degree is low and that of O2 is high, in the present system this can be varied through the gas flow rate of the molecular gases. We have also shown that the NO(X) molecules formation is governed by the surface processes, which is strongly influenced by the state of the surface.
Time-resolved tomographic measurements of temperatures in a thermal plasma jet
Authors: Hlína J , Šonský J
Published: January 2010

Temperatures in a thermal plasma jet were measured using an experimental set-up providing time-resolved scans of plasma optical radiation near 650 nm from four directions. The acquired data were used for reconstructions of time-resolved temperature distributions in measurement planes perpendicular to the plasma jet axis. The plasma torch was fed by the dc power source with a substantial ripple voltage modulation which leads to significant differences between the temperature distributions according to the actual phase of the arc current.
High quality ITO thin films grown by dc and RF sputtering without oxygen
Authors: Tuna Ocal , Selamet Yusuf , Aygun Gulnur , Ozyuzer Lutfi
Published: January 2010

High quality indium tin oxide (ITO) thin films were grown without oxygen by both dc and RF magnetron sputtering techniques on glass substrates. The effects of substrate temperature, film thickness and sputtering method on the structural, electrical and optical properties of the as-grown films were investigated. The results showed that the substrate temperature had substantial effects on the film properties, in particular on the crystallization and resistivity. When the substrate temperature was increased to 150 °C, crystallization in the (2 2 2) plane started appearing for both dc and RF sputtered films. We additionally found that with further increments of substrate temperature, the preferred crystallization orientation changed differently for dc and RF sputtered films. Optical transmission in the visible region for a film thickness of 70 nm was found to be above 85%. The bandgap was calculated to be about 3.64 eV for the substrate temperature of 150 °C for a 70 nm thick film. The value of the bandgap increased with respect to the increment in film thickness as well as substrate temperature. We also measured the temperature dependence of the resistivity and Hall coefficient of the films, and calculated the carrier concentration and Hall mobility. Very low room temperature resistivities for dc and RF magnetron sputtered grown films of about 1.28 × 10−4 Ω cm and 1.29 × 10−4 Ω cm, respectively, were obtained.
Determination of charge carrier transport in radio frequency plasma polymerized aniline thin films
Authors: Sivaraman Sajeev , Anantharaman M R
Published: January 2010

The carrier transport mechanism of polyaniline (PA) thin films prepared by radio frequency plasma polymerization is described in this paper. The mechanism of electrical conduction and carrier mobility of PA thin films for different temperatures were examined using the aluminium–PA–aluminium (Al–PA–Al) structure. It is found that the mechanism of carrier transport in these thin films is space charge limited conduction. J–V studies on an asymmetric electrode configuration using indium tin oxide (ITO) as the base electrode and Al as the upper electrode (ITO–PA–Al structure) show a diode-like behaviour with a considerable rectification ratio.
Gradient index metamaterials realized by drilling hole arrays
Authors: Mei Zhong Lei , Bai Jing , Cui Tie Jun
Published: January 2010

Gradient index metamaterials have wide applications in the microwave and optical fields. Based on the quasi-static theory, such materials at the microwave band have been realized by drilling hole arrays on ordinary dielectric materials. As applications of the gradient index metamaterials, novel devices including a 45° dielectric wave-bending structure, a 16° wave-steering lens and a microwave focusing lens are designed and fabricated. Field mapping measurements validate the proposed gradient index metamaterials and the device designs. The method can be directly and easily extended to the design of cloaks, various lenses, beam shifters and beam-steering devices. It can also be applied in the optical band as long as quasi-static conditions are satisfied. The method and the devices may find applications in integrated circuit systems.
A new model for surface potential decay of corona-charged polymers
Authors: Chen George
Published: January 2010

Surface potential measurement provides a useful tool to gauge the electrical properties of materials. It has been observed that the potential of a sample with an initial high surface potential decays faster than that with an initial lower surface potential, known as the cross-over phenomenon. The phenomenon was found a few decades ago and various theories and models have been proposed. A common feature of the existing models is based on single charge carrier injection from a corona-charged surface. With our recent space charge measurement results on corona-charged samples, double injection from both electrodes has been verified. Based on this new fact, a new model based on bipolar charge injection is proposed and initial numerical simulation reveals that the surface potential cross-over phenomenon can occur under bipolar charge injection.
Outlook vs. Futures: Three Decades of Evidence in Hog and Cattle Markets
Authors: Colino Evelyn V. , Irwin Scott H.
Published: January 2010

The accuracy of hog and cattle price forecasts from four outlook programs is compared with forecasts derived from futures markets. Most of the series begin in the mid to late 1970s and end in 2007. Root mean squared error (RMSE) comparisons indicate the difference between outlook and futures RMSE is relatively small in most cases. In directional terms, outlook forecasts beat futures prices only 2 out of 11 times in hogs, and 1 out of 7 times in cattle. However, the null hypothesis that futures encompasses outlook is rejected in 5 of 11 cases for hogs, and 4 of 7 cases for cattle.
Semiparametric Estimation of Consumer Demand Systems with Micro Data
Authors: Sam Abdoul G. , Zheng Yi
Published: January 2010

Maximum likelihood and two‐step estimators of censored demand systems yield biased and inconsistent parameter estimates when the assumed joint distribution of disturbances is incorrect. This paper proposes a semiparametric estimator that retains the computational advantage of the two‐step approach but is immune to distributional misspecification. The key difference between the proposed estimator and the two‐step estimator is that the parameters of the binary censoring equations are estimated using a distribution‐free single‐index model. We implement the proposed estimator using household‐level data obtained from the Hainan province in China. specification test lends support to our approach.
Is Expected Utility Theory Applicable? A Revealed Preference Test
Authors: Just David R. , Peterson Hikaru Hanawa
Published: January 2010

We proffer a method to assess the adequacy of expected utility theory (EUT) in empirical studies involving discrete and continuous choices. The method calibrates a utility function to revealed choices and rejects EUT for absurd degrees of implied concavity over the wealth at risk. We find EUT rejections in cases where risk‐averse choices are made between gambles with similar stakes, regardless of their absolute sizes. EUT is shown to be applicable only when expected payoffs of gambles are similar, or when more than half of wealth is at risk. We illustrate our method with an application to agricultural production.
Optimal Harvest Licensing When Harvest Success Is Uncertain
Authors: Hussain Abul Maala Tanvir , Tschirhart John
Published: January 2010

Optimal harvests using individual licenses are determined given that a licensee's probabilities of procuring a license and harvesting successfully are less than one. Probabilities are dependent on the resource stock and the number of licenses, and licensees benefit from the harvesting experience itself. Recreational fishing and hunting are applications. The optimum stock may be greater or less than the maximum sustained yield stock, and investing in more stock decreases licenses but increases licensees' success. The optima depend on whether the license agency views applicants as dedicated or social, where the latter are relatively more interested in procuring a license than in a successful harvest.
A National, Longitudinal Study of the Effects of Concentrated Hog Production on Ambient Air Pollution
Authors: Sneeringer Stacy
Published: January 2010

The Environmental Protection Agency is considering regulation of large‐scale hog producers under the federal Clean Air Act, but little is understood about livestock's effects on ambient air quality at the national level. I use the geographic changes in swine industry concentration between 1980 and 2002 to identify ambient air pollution attributable to this industry, controlling for numerous other factors. Doubling the number of hogs per square mile yields a 6.6% increase in sulfur‐based ambient air pollution. Externality costs are estimated to be greater than possible regulatory requirements, suggesting societal gains from regulation.
Observed Changes in Risk during Naturopathic Treatment of Hypertension
Authors: Bradley Ryan , Kozura Eva , Kaltunas Jennifer , Oberg Erica B. , Probstfield Jeffery , Fitzpatrick Annette L.
Published: January 2010

Few outcome assessments are published from complementary and alternative medicine (CAM) practices. We aimed to describe patient and practice characteristics of ND care for hypertension (HTN), quantify changes in blood pressure (BP), and evaluate the proportion achieving control of HTN during care. A retrospective, observational study of ND practice in HTN was performed in an outpatient clinic in WA State. Eighty‐five charts were abstracted for the final analysis. At initiation of care, the mean patient age was 61 years, with 51% having stage 2 HTN, despite common use of anti‐hypertensive medications (47%). Patients with both stage 1 and stage 2 HTN appeared to improve during care, with stage 2 patients achieving mean reductions of −26 mmHg (P < .0001) and −11 mmHg (P < .0001) in systolic BP (SBP) and diastolic BP (DBP), respectively. The proportion of patients achieving control (<140/90 mmHg) in both SBP and DBP was increased significantly from 14 to 44% (P < .033), although the statistical significance was not maintained upon correction for multiple comparisons. BP appears to improve during ND care for HTN, in a high‐risk population. Randomized trials are warranted.
Evaluation ofIn VitroUterotonic Activities of Fruit Extracts ofFicus asperifoliain Rats
Authors: Watcho Pierre , Ngadjui Esther , Alango Nkeng-Efouet Pepin , Benoît Nguelefack Telesphore , Kamanyi Albert
Published: January 2010

The aim of the present study was to determine the uterotonic activities ofFicus asperifoliaand investigate its mechanism. The effects of aqueous and methanol extracts of the dried fruits ofF. asperifolia(0.05–1.60 mg mL−1) were evaluated on estrogenized isolated rat uterus in the presence and absence of atropine (1.73–55.27 nM), pyrilamine maleate (1.25 × 10−3to 40 × 10−3 M), indomethacin (0.06 × 10−5to 2.00 × 10−5 M) or hexamethonium (0.66 × 10−4to 21.43 × 10−4 M). Aqueous (EC50, 0.36 mg mL−1) and methanol (EC50, 0.22 mg mL−1) extracts as well as oxytocin (EC50, 0.02 nM), acetylcholine (EC50, 7.87 nM) and histamine (EC50, 0.76 nM) evoked concentration‐dependent contractions of the uterus. Atropine, pyrilamine maleate and indomethacin concentration dependently blocked the response of the uterus to acetylcholine (IC50, 4.82 nM), histamine (IC50, 2.49 nM) and oxytocin (IC50, 0.07 nM), respectively, and to aqueous extract. Hexamethonium produced graded decreases in oxytocin‐induced uterine contractions (IC50, 0.37 μM), but did not prevent the contractile effects of the aqueous extract (IC50, 9.88 μM). These results suggest thatF. asperifolia‐induced uterotonic effect is related to the release of prostaglandins and contraction of the myometrial cells through muscarinic, oxytocic and H1histamine receptors. These data further give added value to the ethnic use ofF. asperifoliafor its abortificient and contraceptive properties.
Spontaneous vertebral osteomyelitis due to Staphylococcus epidermidis
Authors: Isenberg Yonatan , Parada Jorge P.
Published: January 2010

Few reports in the literature have documented ‘spontaneous’ vertebral osteomyelitis due to Staphylococcus epidermidis. Herein, we describe a case of S. epidermidis lumbar osteomyelitis presenting as progressive back pain, but without a known port of entry or underlying pre-existing high-risk predisposing conditions. A low threshold for the consideration of infectious osteomyelitis is warranted in persons presenting with new, progressive back pain.
McKay agar enables routine quantification of the ‘Streptococcus milleri’ group in cystic fibrosis patients
Authors: Sibley Christopher D. , Grinwis Margot E. , Field Tyler R. , Parkins Michael D. , Norgaard Jens C. , Gregson Daniel B. , Rabin Harvey R. , Surette Michael G.
Published: January 2010

The ‘Streptococcus milleri’ group (SMG) has recently been recognized as a contributor to bronchopulmonary disease in cystic fibrosis (CF). Routine detection and quantification is limited by current CF microbiology protocols. McKay agar was developed previously for the semi-selective isolation of this group. Here, McKay agar was validated against a panel of clinical SMG isolates, which revealed improved SMG recovery compared with Columbia blood agar. The effectiveness of this medium was evaluated by appending it to the standard CF sputum microbiology protocols in a clinical laboratory for a 6-month period. All unique colony types were isolated and identified by 16S rRNA gene sequencing. Whilst a wide variety of organisms were isolated, members of the SMG were the most prevalent bacteria cultured, and McKay agar allowed routine quantification of the SMG from 103 to >108 c.f.u. ml−1 directly from sputum. All members of the SMG were detected [Streptococcus anginosus (40.7 %), Streptococcus intermedius (34.3 %) and Streptococcus constellatus (25 %)] with an overall prevalence rate of 40.6 % in our adult CF population. Without exception, samples where SMG isolates were cultured at 107 c.f.u. ml−1 or greater were associated with pulmonary exacerbations. This study demonstrates that McKay agar can be used routinely to quantify the SMG from complex clinical samples.
Swarming motility, secretion of type 3 effectors and biofilm formation phenotypes exhibited within a large cohort of Pseudomonas aeruginosa clinical isolates
Authors: Murray Thomas S. , Ledizet Michel , Kazmierczak Barbara I.
Published: January 2010

Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen capable of acutely infecting or persistently colonizing susceptible hosts. P. aeruginosa colonizes surfaces in vitro by either biofilm formation or swarming motility. The choice of behaviour is influenced by the physical properties of the surface and specific nutrient availability, and subject to regulatory networks that also govern type 2 and type 3 protein secretion. Biofilm formation by clinical isolates has been well-studied. However, the swarming behaviour of human isolates has not been extensively analysed. We collected isolates from 237 hospitalized patients without cystic fibrosis and analysed motility and secretion phenotypes of each isolate. We found biofilm formation and swarming to be negatively associated, while swarming was positively associated with the secretion of both proteases and type 3 exoenzymes. Most isolates were capable of type 3 secretion and biofilm formation, even though these traits are considered to favour distinct modes of pathogenesis. Our data demonstrate that while clinical isolates display diverse motility, biofilm and secretion phenotypes, many of the predicted relationships between swarming motility and other phenotypes observed in laboratory strains also hold true for bacteria isolated from human patients.
Helicobacter pylori antibiotic resistance and [13C]urea breath test values
Authors: De Francesco Vincenzo , Zullo Angelo , Perna Federico , Giorgio Floriana , Hassan Cesare , Vannella Lucy , Cristofari Francesca , Panella Carmine , Vaira Dino , Ierardi Enzo
Published: January 2010

A correlation between δ over baseline (DOB) values of the [13C]urea breath test (UBT) and Helicobacter pylori clarithromycin resistance has been reported, suggesting a possible predictive role of UBT in therapeutic outcome. However, available data are limited and conflicting. This study aimed to clarify this issue, assessing the possible relationship between H. pylori resistance towards different antibiotics (clarithromycin, metronidazole and levofloxacin) and UBT values. The data showed similar DOB values between susceptible and resistant strains for clarithromycin (46.9±32.3 vs 45.7±30.6; P=0.8), metronidazole (46.4±29.6 vs 47.4±37.9; P=0.8), and levofloxacin (45.0±30.2 vs 54.2±38.4; P=0.08). Likewise, comparable DOB values were observed between susceptible and multidrug-resistant strains (45.4±29.6 vs 54.8±44.8; P=0.1). In conclusion, our data failed to find a significant correlation between UBT values and H. pylori antibiotic resistance.
Mycobacteriophage Ms6 LysB specifically targets the outer membrane of Mycobacterium smegmatis
Authors: Gil Filipa , Grzegorzewicz Anna E. , Catalão Maria João , Vital João , McNeil Michael R. , Pimentel Madalena
Published: January 2010

LysB, a mycobacteriophage Ms6-encoded protein, was previously identified as a lipolytic enzyme able to hydrolyse the ester bond in lipase and esterase substrates. In the present work, we show that LysB can hydrolyse lipids containing mycolic acids from the outer membrane of the mycobacterial cell wall. LysB was shown to hydrolyse the mycolic acids from the mycolyl-arabinogalactan–peptidoglycan complex where the mycolates of the inner leaflet of the outer membrane are covalently attached to an arabinosyl head group. In addition, treatment of the extractable lipids from Mycobacterium smegmatis, Mycobacterium bovis BCG and Mycobacterium tuberculosis H37Ra with LysB showed that trehalose 6,6′-dimycolate (TDM), a trehalose diester of two mycolic acid molecules, was hydrolysed by the enzyme. We have also determined the structures of the mycolic acid molecules that form the M. smegmatis TDM. The identification of a phage-encoded enzyme that targets the outer membrane of the mycobacterial cell wall enhances our understanding of the mechanism of mycobacteriophage lysis.
The outer membrane protein OprQ and adherence of Pseudomonas aeruginosa to human fibronectin
Authors: Arhin Abraham , Boucher Cliff
Published: January 2010

Outer membrane proteins of the Gram-negative organism Pseudomonas aeruginosa play a significant role in membrane permeability, antibiotic resistance, nutrient uptake, and virulence in the infection site. In this study, we show that the P. aeruginosa outer membrane protein OprQ, a member of the OprD superfamily, is involved in the binding of human fibronectin (Fn). Some members of the OprD subfamily have been reported to be important in the uptake of nutrients from the environment. Comparison of wild-type and mutant strains of P. aeruginosa revealed that inactivation of the oprQ gene does not reduce the growth rate. Although it does not appear to be involved in nutrient uptake, an increased doubling time was reproducibly observed with the loss of OprQ in P. aeruginosa. Utilizing an oprQ–xylE transcriptional fusion, we determined that the PA2760 gene, encoding OprQ, was upregulated under conditions of decreased iron and magnesium. This upregulation appears to occur in early exponential phase. Insertional inactivation of PA2760 in the P. aeruginosa wild-type background did not produce a significant increase in resistance to any antibiotic tested, a phenotype that is typical of OprD family members. Interestingly, the in trans expression of OprQ in the ΔoprQ PAO1 mutant resulted in increased sensitivity to certain antibiotics. These findings suggest that OprQ is under dual regulation with other P. aeruginosa genes. Intact P. aeruginosa cells are capable of binding human Fn. We found that loss of OprQ resulted in a reduction of binding to plasmatic Fn in vitro. Finally, we present a discussion of the possible role of the P. aeruginosa outer membrane protein OprQ in adhesion to epithelial cells, thereby increasing colonization and subsequently enhancing lung destruction by P. aeruginosa.
The Swedish new variant of Chlamydia trachomatis: genome sequence, morphology, cell tropism and phenotypic characterization
Authors: Unemo Magnus , Seth-Smith Helena M. B. , Cutcliffe Lesley T. , Skilton Rachel J. , Barlow David , Goulding David , Persson Kenneth , Harris Simon R. , Kelly Anne , Bjartling Carina , Fredlund Hans , Olcén Per , Thomson Nicholas R. , Clarke Ian N.
Published: January 2010

Chlamydia trachomatisis a major cause of bacterial sexually transmitted infections worldwide. In 2006, a new variant ofC. trachomatis(nvCT), carrying a 377 bp deletion within the plasmid, was reported in Sweden. This deletion included the targets used by the commercial diagnostic systems from Roche and Abbott. The nvCT is clonal (serovar/genovar E) and it spread rapidly in Sweden, undiagnosed by these systems. The degree of spread may also indicate an increased biological fitness of nvCT. The aims of this study were to describe the genome of nvCT, to compare the nvCT genome to all availableC. trachomatisgenome sequences and to investigate the biological properties of nvCT. An early nvCT isolate (Sweden2) was analysed by genome sequencing, growth kinetics, microscopy, cell tropism assay and antimicrobial susceptibility testing. It was compared with relevantC. trachomatisisolates, including a similar serovar EC. trachomatiswild-type strain that circulated in Sweden prior to the initially undetected expansion of nvCT. The nvCT genome does not contain any major genetic polymorphisms – the genes for central metabolism, development cycle and virulence are conserved – or phenotypic characteristics that indicate any altered biological fitness. This is supported by the observations that the nvCT and wild-typeC. trachomatisinfections are very similar in terms of epidemiological distribution, and that differences in clinical signs are only described, in one study, in women. In conclusion, the nvCT does not appear to have any altered biological fitness. Therefore, the rapid transmission of nvCT in Sweden was due to the strong diagnostic selective advantage and its introduction into a high-frequency transmitting population.
Genome update: the 1000th genome – a cautionary tale
Authors: Lagesen Karin , Ussery Dave W. , Wassenaar Trudy M.
Published: January 2010

There are now more than 1000 sequenced prokaryotic genomes deposited in public databases and available for analysis. Currently, although the sequence databases GenBank, DNA Database of Japan and EMBL are synchronized continually, there are slight differences in content at the genomes level for a variety of logistical reasons, including differences in format and loading errors, such as those caused by file transfer protocol interruptions. This means that the 1000th genome will be different in the various databases. Some of the data on the highly accessed web pages are inaccurate, leading to false conclusions for example about the largest bacterial genome sequenced. Biological diversity is far greater than many have thought. For example, analysis of multiple Escherichia coli genomes has led to an estimate of around 45 000 gene families — more genes than are recognized in the human genome. Moreover, of the 1000 genomes available, not a single protein is conserved across all genomes. Excluding the members of the Archaea, only a total of four genes are conserved in all bacteria: two protein genes and two RNA genes.
Ab initio structure determination of phase II of racemic ibuprofen by X-ray powder diffraction
Authors: Derollez Patrick , Dudognon Emeline , Affouard Frédéric , Danède Florence , Correia Natália T. , Descamps Marc
Published: January 2010

Annealing of the quenched ibuprofen at 258 K yielded a new crystalline form, called phase II. Powder X-ray diffraction patterns of this phase II were recorded with a laboratory diffractometer equipped with an INEL G3000 goniometer and a curved position-sensitive detector CPS120. The starting structural model was found by a Monte-Carlo simulated annealing method. The final structure was obtained through Rietveld refinements with rigid-body constraints for the phenyl group and soft restraints on the other interatomic bond lengths and bond angles. The cell volume is 5% larger than that of the conventional phase I at 258 K. It is also shown that the orientation of the propanoic acid group is drastically changed with respect to phase I, leading to strong modifications of the orientation of the O—H...O hydrogen bonds with respect to the chains of dimers. These structural considerations could explain the metastable character of this phase II.