bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of spontaneous polarization on GaInN/GaN quantum well structures
Authors: Thomsen M. , Jönen H. , Rossow U. , Hangleiter A.
Published: June 2011

Using electron beam irradiation, cathodoluminescence, and photoluminescence under ultrahigh vacuum conditions, we study the effect of spontaneous polarization on polar (0001) and nonpolar (11−00) GaInN/GaN quantum well structures. We use cathodoluminescence measurements with an electron beam irradiation time of up to several hours. A drastic blueshift of the quantum well emission accompanied by a 100-fold increase of intensity is observed in polar samples. These changes can be described by an activation of the spontaneous polarization field due to the desorption of surface charges, which counteracts the piezoelectric field in the quantum well. Etching or annealing of the surface leads to similar effects. The influence of the sample structure was investigated by varying the cap thickness of the samples. A different time- dependent behavior of changes in the quantum well emission energy and the intensity depending on cap thickness and acceleration voltage was observed. This can be explained by de-screening and screening effects induced by the electron beam which are discussed in detail. For nonpolar (11−00) samples, no change in quantum well emission energy or intensity was observed. This is consistent with a spontaneous-polarization-induced surface field in the c-plane case and verifies the absence of the spontaneous polarization field in the nonpolar (11−00) direction.
A multiconfigurational time-dependent Hartree-Fock method for excited electronic states. I. General formalism and application to open-shell states
Authors: Miranda R. P. , Fisher A. J. , Stella L. , Horsfield A. P.
Published: June 2011

The solution of the time-dependent Schrödinger equation for systems of interacting electrons is generally a prohibitive task, for which approximate methods are necessary. Popular approaches, such as the time-dependent Hartree-Fock (TDHF) approximation and time-dependent density functional theory (TDDFT), are essentially single-configurational schemes. TDHF is by construction incapable of fully accounting for the excited character of the electronic states involved in many physical processes of interest; TDDFT, although exact in principle, is limited by the currently available exchange-correlation functionals. On the other hand, multiconfigurational methods, such as the multiconfigurational time-dependent Hartree-Fock (MCTDHF) approach, provide an accurate description of the excited states and can be systematically improved. However, the computational cost becomes prohibitive as the number of degrees of freedom increases, and thus, at present, the MCTDHF method is only practical for few-electron systems. In this work, we propose an alternative approach which effectively establishes a compromise between efficiency and accuracy, by retaining the smallest possible number of configurations that catches the essential features of the electronic wavefunction. Based on a time-dependent variational principle, we derive the MCTDHF working equation for a multiconfigurational expansion with fixed coefficients and specialise to the case of general open-shell states, which are relevant for many physical processes of interest.
Rotating sample magnetometer for cryogenic temperatures and high magnetic fields
Authors: Eisterer M. , Hengstberger F. , Voutsinas C. S. , Hörhager N. , Sorta S. , Hecher J. , Weber H. W.
Published: June 2011

We report on the design and implementation of a rotating sample magnetometer (RSM) operating in the variable temperature insert (VTI) of a cryostat equipped with a high-field magnet. The limited space and the cryogenic temperatures impose the most critical design parameters: the small bore size of the magnet requires a very compact pick-up coil system and the low temperatures demand a very careful design of the bearings. Despite these difficulties the RSM achieves excellent resolution at high magnetic field sweep rates, exceeding that of a typical vibrating sample magnetometer by about a factor of ten. In addition the gas-flow cryostat and the high-field superconducting magnet provide a temperature and magnetic field range unprecedented for this type of magnetometer.
Upper continuity bounds on the relative q-entropy for q > 1
Authors: Rastegin Alexey E.
Published: June 2011

Generalized entropies and relative entropies are the subject of active research. Similar to the standard relative entropy, the relative q-entropy is generally unbounded for q > 1. Upper bounds on the quantum relative q-entropy in terms of norm distances between its arguments are obtained in finite-dimensional context. These bounds characterize a continuity property in the sense of Fannes.
Room-temperature-operated sensitive hybrid gas sensor based on amorphous indium gallium zinc oxide thin-film transistors
Authors: Zan Hsiao-Wen , Li Chang-Hung , Yeh Chun-Cheng , Dai Ming-Zhi , Meng Hsin-Fei , Tsai Chuang-Chuang
Published: June 2011

An organic sensing layer is capped onto an amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) to form a hybrid sensor. The organic layer, served as a second gate, forms a p-n junction with the a-IGZO film. Oxidizing or reducing vapor molecules act like electron acceptors or electron donors to change the potential of the organic layer and the current of a-IGZO TFT. A sensitive and reversible response to 100 ppb ammonia and 100 ppb acetone is obtained at room temperature. This letter opens a route to develop low-cost large-area bio/chemical sensor arrays based on the emerging a-IGZO TFT technology.
Room temperature operation of GaAsP(N)/GaP(N) quantum well based light-emitting diodes: Effect of the incorporation of nitrogen
Authors: Robert C. , Bondi A. , Thanh T. Nguyen , Even J. , Cornet C. , Durand O. , Burin J. P. , Jancu J. M. , Guo W. , Létoublon A. , Folliot H. , Boyer-Richard S. , Perrin M. , Chevalier N. , Dehaese O. , Tavernier K. , Loualiche S. , Le Corre A.
Published: June 2011

This letter deals with the electroluminescence emission at room temperature of two light-emitting diodes on GaP substrate, based on ternary GaAsP/GaP and quaternary GaAsPN/GaPN multiple quantum wells. In agreement with tight-binding calculations, an indirect band gap is demonstrated from the temperature-dependent photoluminescence for the first structure. High efficiency photoluminescence is then observed for the second structure. Strong electroluminescence and photocurrent are measured from the diode structures at room temperature at wavelengths of 660 nm (GaAsP/GaP) and 730 nm (GaAsPN/GaPN). The role of the incorporation of nitrogen on the optical band gap and on the nature of interband transitions is discussed.
Electroluminescence emission from light-emitting diode of p-ZnO/(InGaN/GaN) multiquantum well/n-GaN
Authors: Park Tae-Young , Choi Yong-Seok , Kim Sang-Mook , Jung Gun-Young , Park Seong-Ju , Kwon Bong-Joon , Cho Yong-Hoon
Published: June 2011

We report on the fabrication and characteristics of light-emitting diodes (LEDs) which consist of antimony (Sb) doped p-ZnO, (InGaN/GaN) multiquantum well (MQW), and n-GaN. An electroluminescence (EL) emission at a wavelength of 468 nm is observed from the hybrid LEDs after thermal annealing at 750 °C, showing that Sb-doped p-ZnO can be used as a hole supplying layer in hybrid LEDs. Furthermore, the EL peaks are redshifted as the injection current is increased, indicating that the compressive strain in MQW layers is relaxed due to Sb-doped p-ZnO layer.
Reaction of aluminum clusters with water
Authors: Ohmura Satoshi , Shimojo Fuyuki , Kalia Rajiv K. , Kunaseth Manaschai , Nakano Aiichiro , Vashishta Priya
Published: June 2011

The atomistic mechanism of rapid hydrogen production from water by an aluminum cluster is investigated by ab initio molecular dynamics simulations on a parallel computer. A low activation-barrier mechanism of hydrogen production is found, in which a pair of Lewis acid and base sites on the cluster surface plays a crucial role. Hydrogen production is assisted by rapid proton transport in water via a chain of hydrogen-bond switching events similar to the Grotthuss mechanism, where hydroxide ions are converted to water molecules at the Lewis-acid sites and hydrogen atoms are supplied at the Lewis-base sites. The activation free energy is estimated along various reaction paths associated with hydrogen production, and the corresponding reaction rates are discussed based on the transition state theory.
Activation-induced cytidine deaminase (AID) is required for B-cell tolerance in humans
Authors: Meyers Greta , Ng Yen-Shing , Bannock Jason M. , Lavoie Aubert , Walter Jolan E. , Notarangelo Luigi D. , Kilic Sara S. , Aksu Guzide , Debré Marianne , Rieux-Laucat Frédéric , Conley Mary Ellen , Cunningham-Rundles Charlotte , Durandy Anne , Meffre Eric
Published: June 2011

Impaired immune functions leading to primary immunodeficiencies often correlate with paradoxical autoimmune complications; patients with hyper-IgM syndromes who are deficient in activation-induced cytidine deaminase (AID), which is required for class-switch recombination and somatic hypermutation, are prone to develop autoimmune diseases. To investigate the impact of AID-deficiency on early B-cell tolerance checkpoints in humans, we tested by ELISA the reactivity of recombinant antibodies isolated from single B cells from AID-deficient patients. New emigrant/transitional and mature naive B cells from AID-deficient patients express an abnormal Ig repertoire and high frequencies of autoreactive antibodies, demonstrating that AID is required for the establishment of both central and peripheral B-cell tolerance. In addition, B-cell tolerance was further breached in AID-deficient patients as illustrated by the detection of anti-nuclear IgM antibodies in the serum of all patients. Thus, we identified a major and previously unsuspected role for AID in the removal of developing autoreactive B cells in humans.
Effects of gap and elevated pressure on ethanol reforming in a non-thermal plasma reactor
Authors: Hoang Trung Q , Zhu Xinli , Lobban Lance L , Mallinson Richard G
Published: June 2011

Production of hydrogen for fuel cell vehicles, mobile power generators and for hydrogen-enhanced combustion from ethanol is demonstrated using energy-efficient non-thermal plasma reforming. A tubular reactor with a multipoint electrode system operated in pulsed mode was used. Complete conversion can be achieved with high selectivity (based on ethanol) of H2 and CO of 111% and 78%, respectively, at atmospheric pressure. An elevated pressure of 15 psig shows improvement of selectivity of H2 and CO to 120% and 87%, with a significant reduction of C2H
x
side products. H2 selectivity increased to 127% when a high ratio (29.2) of water-to-ethanol feed was used. Increasing CO2 selectivity is observed at higher water-to-ethanol ratios indicating that the water gas shift reaction occurs. A higher productivity and lower C2H
x
products were observed at larger gas gaps. The highest overall energy efficiency achieved, including electrical power consumption, was 82% for all products or 66% for H2 only.
Analysis of solid products formed in atmospheric non-thermal carbon monoxide plasma
Authors: Geiger Robert , Staack David
Published: June 2011

Thermodynamic analysis indicates that non-equilibrium plasma-chemistry of carbon monoxide can lead to the deposition of solid carbon oxides at low temperatures. Using a dielectric barrier discharge we are able to create deposits from CO readily at atmospheric pressure conditions. Deposition rates are on the order of 0.2 mg min−1 at power of 12 W corresponding to about 1000 kW-h kg−1. Deposition rates increase with power although the most efficient deposition of carbon oxides is at lower power. Higher powers tend to increase the gas temperature and the carbon content of the films; this can be related to chemical kinetic considerations. Deposition rates are not significant functions of flow rate in the reactor, due to no significant depletion of the precursor over the range of flow rates tested. Gaseous products of the reactor were mainly unconverted CO precursor and trace amounts of CO2. The deposited material was characterized by elemental analysis, MALDI and ESI MS, FTIR and NMR. The material has chemical composition and characteristics similar to high pressure CO polymers and carbon suboxide polymers chemically formed from the monomer. Although some significant differences are observed including: a more disordered structure, slightly higher carbon incorporation and hydrogen incorporation, both latter conditions potentially resulting from the film reacting with water vapour after exposure to air.
Dry reforming of methane over a Ni/Al2O3 catalyst in a coaxial dielectric barrier discharge reactor
Authors: Tu Xin , Gallon Helen J , Twigg Martyn V , Gorry Peter A , Whitehead J Christopher
Published: June 2011

A coaxial double dielectric barrier discharge (DBD) reactor is developed for plasma-catalytic conversion of CH4 and CO2 into syngas and other valuable products. A supported metal catalyst (Ni/Al2O3) reduced in a methane discharge is fully packed into the discharge region. The influence of the Ni/Al2O3 catalyst packed into the gas gap on the electrical characteristics of the discharge is investigated. The introduction of the catalyst pellets leads to a transition in discharge behaviour from a typical filamentary microdischarge to a combination of spatially limited microdischarges and a predominant surface discharge on the catalyst surface. It is also found that the breakdown voltage of the CH4/CO2 discharge significantly decreases when the reduced catalyst is fully packed in the discharge area. Conductive Ni active sites dispersed on the catalyst surface contribute to the expansion of the discharge and enhancement of charge transfer. In addition, plasma-catalytic dry reforming of CH4 is carried out with the reduced Ni/Al2O3 catalyst using a mixing ratio of CH4/CO2 = 1 and a total flow rate of 50 ml min−1. An increase in H2 selectivity is observed compared with dry CH4 reforming with no catalyst, while the H2/CO molar ratio significantly increases from 0.84 to 2.53 when the catalyst is present.
Plasma–catalytic hybrid system using spouted bed with a gliding arc discharge: CH4 reforming as a model reaction
Authors: Lee H , Sekiguchi H
Published: June 2011

A combination of a gliding arc discharge and a spouted catalytic bed was used to investigate a plasma–catalytic hybrid system using CH4 reforming as a model reaction. Alumina-supported catalysts that contained 0.5 wt% of Pt, Pd, Rh, and Ru (denoted as Pt/Al2O3, Pd/Al2O3, Rh/Al2O3 and Ru/Al2O3, respectively) were used. For comparison, active Al2O3 particles were also examined. The conversion of CH4 and the selectivity of the product were investigated by changing the feed flow rate and reaction time. The production of C2H2, H2 and soot was observed in the gliding arc discharge without a catalyst. Using Pt/Al2O3 and Pd/Al2O3with the gliding arc discharge, C2H4, C2H6 and C2H2 were produced. It is considered that C2H4 and C2H6 were formed by the hydrogenation of C2H2 on the active site of Pt/Al2O3 and Pd/Al2O3. A stronger resistance to deactivation was shown in the presence of Pd/Al2O3 than in the presence of Pt/Al2O3, whereas the selectivity of hydrocarbon using Rh/Al2O3 and Ru/Al2O3 showed a tendency similar to that in active Al2O3 and non-catalytic experiments. The proposed reactor has a potential to improve the selectivity of the plasma process.
Dissociation of CO2 in a low current gliding arc plasmatron
Authors: Nunnally T , Gutsol K , Rabinovich A , Fridman A , Gutsol A , Kemoun A
Published: June 2011

The process of CO2 dissociation was studied in a non-equilibrium gliding arc plasmatron (GAP). The GAP was designed not only for efficient reforming but also to ensure significant variability of reactor parameters. The effect of vortex flow configuration on efficiency was also studied in the reactor by comparing forward vortex flow and reverse vortex flow. The maximum thermodynamic efficiency of the dissociation process was determined to be approximately 43%. The high level of efficiency may be attributed to non-equilibrium vibrational excitation of CO2 and a high-temperature gradient between gliding arc and the surrounding gas that results in fast quenching.
Selective conversion of methane to synthetic fuels using dielectric barrier discharge contacting liquid film
Authors: Nozaki Tomohiro , Goujard Valentin , Yuzawa Shuhei , Moriyama Shota , Ağıral Anıl , Okazaki Ken
Published: June 2011

This paper presents the reaction mechanism of single-step methane partial oxidation to methanol at room temperature using non-thermal plasma microreactor. Macroscopic quantities of hydrogen peroxide (H2O2) and methyl hydroperoxide (CH3OOH) are produced when methane is partially oxidized at room temperature (about 5 °C). CH3OOH is known to be the principle intermediate of incomplete methane oxidation product such as CH3OH and HCHO, but has not been demonstrated experimentally so far. H2O2 promotes post-plasma oxidation of oxygenates in the condensed plasma-synthesized liquid. At an early stage of in-liquid oxidation, H2O2 oxidizes HCHO into HCOOH preferentially; subsequently, HCOOH is fully oxidized to CO2 and H2O. Depending upon the concentration of oxygenates and H2O2, electrical conductivity of the plasma solution dramatically increased, which detrimentally influences plasma properties. Methane partial oxidation with air was also investigated from a practical viewpoint. Generation of active nitrogen species (ANS) is the key to promoting overall methane conversion in the presence of oxygen; however, fragile oxygenates were also decomposed by ANS, thus selectivity for useful oxygenates was degraded in the presence of nitrogen. When oxygen is fully consumed, CH4 conversion is also terminated and water gas shift reaction (CO + H2O = CO2 + H2) becomes predominant.
Final report on the Seventh International Comparison of Absolute Gravimeters (ICAG 2005)*
Authors: Jiang Z , Francis O , Vitushkin L , Palinkas V , Germak A , Becker M , D'Agostino G , Amalvict M , Bayer R , Bilker-Koivula M , Desogus S , Faller J , Falk R , Hinderer J , Gagnon C , Jakob T , Kalish E , Kostelecky J , Lee Chiungwu , Liard J , Lokshyn Y , Luck B , Mäkinen J , Mizushima S , Le Moigne N , Origlia C , Pujol E R , Richard P , Robertsson L , Ruess D , Schmerge D , Stus Y , Svitlov S , Thies S , Ullrich C , Van Camp M , Vitushkin A , Ji W , Wilmes H
Published: June 2011

The Bureau International des Poids et Mesures (BIPM), Sèvres, France, hosted the 7th International Comparison of Absolute Gravimeters (ICAG) and the associated Relative Gravity Campaign (RGC) from August to September 2005.

ICAG 2005 was prepared and performed as a metrological pilot study, which aimed:

(1) To determine the gravity comparison reference values;

(2) To determine the offsets of the absolute gravimeters; and

(3) As a pilot study to accumulate experience for the CIPM Key Comparisons.

This document presents a complete and extensive review of the technical protocol and data processing procedures. The 1st ICAG–RGC comparison was held at the BIPM in 1980–1981 and since then meetings have been organized every 4 years.

In this paper, we present an overview of how the meeting was organized, the conditions of BIPM gravimetric sites, technical specifications, data processing strategy and an analysis of the final results. This 7th ICAG final report supersedes all previously published reports.

Readings were obtained from participating instruments, 19 absolute gravimeters and 15 relative gravimeters. Precise levelling measurements were carried out and all measurements were performed on the BIPM micro-gravity network which was specifically designed for the comparison.
Spontaneous transition of core radial electric field driven by magnetic islands in the H-1NF heliac
Authors: Kumar S.T.A. , Blackwell B.D. , Howard J. , Harris J.H.
Published: June 2011

This paper reports an experimental observation of spontaneous transition of the core radial electric field to a large positive value (E

r
∼ 5 kV m−1), with a strong electric-field shear (∼700 kV m−2) in a low temperature (T
e ∼ 10 eV) radio frequency generated argon plasma in the H-1NF heliac stellarator. The transition, which seems to be driven by a spontaneous excitation of m = 2 magnetic islands near the core, is associated with a localized increase in the plasma density and excitation of coherent low frequency (∼3 kHz) oscillations possibly due to unstable E

r
shear driven modes. Evidence suggests development of the core electron-root scenario, which previously has been observed only at high temperature electron cyclotron heated plasmas.
eResponseNet: a package prioritizing candidate disease genes through cellular pathways
Authors: Huang Jialiang , Liu Yi , Zhang Wei , Yu Hong , Han Jing-Dong J.
Published: June 2011

Motivation: Although genome-wide association studies (GWAS) have found many common genetic variants associated with human diseases, it remains a challenge to elucidate the functional links between associated variants and complex traits.

Results: We developed a package called eResponseNet by implementing and extending the existing ResponseNet algorithm for prioritizing candidate disease genes through cellular pathways. Using type II diabetes (T2D) as a study case, we demonstrate that eResponseNet outperforms currently available approaches in prioritizing candidate disease genes. More importantly, the package is instrumental in revealing cellular pathways underlying disease-associated genetic variations.

Availability: The eResponseNet package is freely downloadable at http://hanlab.genetics.ac.cn/eResponseNet.

Contact:  jdhan@picb.ac.cn

Supplementary Information:  Supplementary data are available at Bioinformatics online.
Food and feeding habits of cod (Gadus morhua) on the Faroe Bank
Authors: Magnussen Eyðfinn
Published: June 2011

Magnussen, E. 2011. Food and feeding habits of cod (Gadus morhua) on the Faroe Bank. – ICES Journal of Marine Science, 68: 1909–1917. Data from ten bottom surveys on the Faroe Bank during the years 1994–1998 are used to describe the feeding habits of cod on the Faroe Bank. Cod are clearly omnivorous in their diet. Overall, fish were found in 82% of the stomachs, accounting for 59% of the food by weight, but just 35% of the food items by number. Of the fish, lesser sandeel was the most common, making up 78% of the fish biomass consumed. Cannibalism was practically non-existent. In some years, the squid Loligo forbesi formed an important component of the diet, was the main food and identified in up to 64% of the stomachs, and constituting 60% by weight of the diet; in other years, it was a negligible part. Crustaceans were found in 48% of the stomachs, accounting for 16% by weight but as much as 44% by numbers. The diet of cod shifts ontogenetically, with stomach fullness greater and nutrient quality of prey higher for cod <70 cm.
Robert Fabyan and the Nuremberg Chronicle
Authors: Payne M.T.W.
Published: June 2011

This article identifies one of Robert Fabyan's source books, his copy of the Nuremberg Chronicle, which contains extensive notes and annotations in his hand. The volume is among the collections at Guildhall Library, London. The marginal notes are of particular interest, not only for the light they shed on Fabyan's working practice, but also because the similarities with the hands of the extant manuscripts of the latter part of the Great Chronicle of London, and The Newe Cronycles of England and Fraunce (Fabyan's Chronicle), demonstrate Fabyan's involvement in each work. This attribution has been doubted for some time. Fabyan also added interesting ownership and purchase information to the Nuremberg Chronicle.
purL gene expression affects biofilm formation and symbiotic persistence of Photorhabdus temperata in the nematode Heterorhabditis bacteriophora
Authors: An Ruisheng , Grewal Parwinder S.
Published: June 2011

Extensive studies of the well-known legume and rhizobium symbiosis model system suggest that the purine metabolic pathway plays a key role in microbe–plant interactions, although the exact mechanism is unknown. Here, we report the impact of a key purine metabolic gene,purL, on the symbiotic interaction between the bacteriumPhotorhabdus temperataand its nematode partnerHeterorhabditis bacteriophora. Real-time PCR assays showed that thepurLgene was upregulated inP. temperatain the nematode infective juvenile compared with artificial media. Mutation of thepurLgene by in-frame deletion dramatically decreased the capacity of the bacterium to persist in infective juveniles and its ability to form biofilmin vitro. It was further demonstrated thatpurLgene expression was positively related to bacterial biofilm formation and the symbiotic persistence of the bacterium in nematode infective juveniles. A ΔpurLmutant lost the ability to support infective juvenile formation in the media which weakly supported biofilm formation, suggesting that a critical level of biofilm formation is required by the bacteria to support infective juvenile formation and thus establish their partnership. In addition, the defects in both biofilm formation and symbiotic ability due to the disruption of thepurLgene could be partially restored by the addition of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), an intermediate of the purine biosynthesis pathway. Overall, these data indicate that the purine metabolic pathway is important in microbe–animal symbioses, and that it may influence symbiotic interactions at the level of biofilm formation.
Lactobacillus S-layer protein inhibition of Salmonella-induced reorganization of the cytoskeleton and activation of MAPK signalling pathways in Caco-2 cells
Authors: Li Pengcheng , Yu Qinghua , Ye Xiaolan , Wang Zhisheng , Yang Qian
Published: June 2011

Surface layer (S-layer) proteins are crystalline arrays of proteinaceous subunits that are present as the outermost component of the cell wall in severalLactobacillusspecies. The S-layer proteins have been shown to play a role in the antimicrobial activity of certain lactobacilli. However, it is not fully understood how the S-layer proteins exert this biological function. The aim of this study was to test the hypothesis thatLactobacillus acidophilusS-layer proteins antagonizeSalmonellaTyphimurium (S. Typhimurium) infection by protecting against F-actin cytoskeleton rearrangements and the activation of mitogen-activated protein kinase (MAPK) signalling pathways. Monolayer transepithelial electrical resistance (TER) was measured afterS. Typhimurium infection in Caco-2 cultured human intestinal cells withL. acidophilusS-layer proteins. F-actin rearrangement and MAPK activation were also assessed by immunofluorescence staining or Western blotting. The results showed that whenS. Typhimurium was co-incubated with S-layer proteins, theS.Typhimurium-induced Caco-2 cell F-actin rearrangement was reduced, and theS.Typhimurium-induced TER decrease and interleukin 8 (IL-8) secretion were attenuated. Additionally,L. acidophilusS-layer proteins could inhibitS.Typhimurium-induced phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun amino-terminal kinase (JNK) and p38. This study indicates thatL. acidophilusS-layer proteins are able to inhibitS. Typhimurium infection through blockingS. Typhimurium-induced F-actin rearrangements andS. Typhimurium-induced ERK1/2, JNK and p38 activation in Caco-2 cells. These data provide a rationale for the use of lactobacillus S-layer proteins as therapeutic and preventative agents, at least in infectious diarrhoea.
Genetic analysis of surface motility in Acinetobacter baumannii
Authors: Clemmer Katy M. , Bonomo Robert A. , Rather Philip N.
Published: June 2011

The Gram-negative pathogen Acinetobacter baumannii strain M2 was found to exhibit a robust surface motility on low-percentage (0.2–0.4 %) agar plates. These patterns of motility were dramatically different depending on whether Difco or Eiken agar was used. Motility was observed in many, but not all, clinical and environmental isolates. The use of drop collapse assays to demonstrate surfactant production was unsuccessful, and the role of surfactants in A. baumannii M2 motility remains unclear. Surface motility was impaired by an insertion in pilT, encoding a gene product that is often required for retraction of the type IV pilus. Motility was also dependent on quorum sensing, as a null allele in the abaI autoinducer synthase decreased motility, and the addition of exogenous N-(3-hydroxy)-dodecanoylhomoserine lactone (3-OH C12-HSL) restored motility to the abaI mutant. Transposon mutagenesis was used to identify additional genes required for motility and revealed loci encoding various functions: non-ribosomal synthesis of a putative lipopeptide, a sensor kinase (BfmS), a lytic transglycosylase, O-antigen biosynthesis (RmlB), an outer membrane porin (OmpA) and de novo purine biosynthesis (PurK). Two of the above genes required for motility were highly activated by quorum sensing, and may explain, in part, the requirement for quorum sensing in motility.
Maintenance nitrogen requirements of adult female ostriches (Struthio camelus)
Authors: Bennett D. C. , Kaneko A. , Karasawa Y.
Published: June 2011

Successful ostrich farming requires knowledge of the nutritional needs of the birds. While much information is available on the nutritional value of various feed ingredients fed to ostriches, there is little known about their specific nutrient requirements. In this study, we measured the maintenance nitrogen requirements (MNR) of ostriches by nitrogen balance. We predict, based on the previous analysis of nitrogen requirements of various species of birds, that ostriches would have a MNR of 13.6–19.1 g N/day and a total endogenous nitrogen loss (TENL) of 2.8–5.1 g N/day. Three adult female ostriches were fed five pelleted diets containing 0.6–2.3% N [4–14.6% crude protein (CP)], 17.5 kJ/g gross energy (11.4 kJ/g ME) and 30% neutral detergent fibre. Each dietary trial consisted of a 10‐day adaptation period, followed by a 5‐day total excreta collection period. Body mass (109 ± 3 kg) and metabolizable energy intake (20.5 ± 0.7 MJ/day) were unaffected by dietary nitrogen levels. After correcting for excreta nitrogen losses during drying, MNR was calculated to be 481 mg N/kg0.75/day or 16.2 g N/day (100 g CP/day), and TENL as 310 mg N/kg0.75/day or 10.5 g N/day. Failure to correct for the 10.9 ± 4.1% average N losses during drying would underpredict the ‘true’ MNR by 35% and TENL by 46%. Our estimate for MNR of ostriches predicts a dietary requirement of 6.7% protein. Our estimate of TENL was nearly twice that predicted, possibly reflecting the high fibre content of their diet.
Quality of Life and Sexual Health After Sex Reassignment Surgery in Transsexual Men
Authors: Wierckx Katrien , Van Caenegem Eva , Elaut Els , Dedecker David , Van de Peer Fleur , Toye Kaatje , Weyers Steven , Hoebeke Piet , Monstrey Stan , De Cuypere Griet , T’Sjoen Guy
Published: June 2011

Introduction

Although sexual health after genital surgery is an important outcome factor for many transsexual persons, little attention has been attributed to this subject.

Aims

To provide data on quality of life and sexual health after sex reassignment surgery (SRS) in transsexual men.

Methods

A single-center, cross-sectional study in 49 transsexual men (mean age 37 years) after long-term testosterone therapy and on average 8 years after SRS. Ninety-four percent of the participants had phalloplasty.

Main Outcome Measures

Self-reported physical and mental health using the Dutch version of the Short Form-36 Health Survey; sexual functioning before and after SRS using a newly constructed specific questionnaire.

Results

Compared with a Dutch reference population of community-dwelling men, transsexual men scored well on self-perceived physical and mental health. The majority reported having been sexually active before hormone treatment, with more than a quarter having been vaginally penetrated frequently before starting hormone therapy. There was a tendency toward less vaginal involvement during hormone therapy and before SRS. Most participants reported an increase in frequency of masturbation, sexual arousal, and ability to achieve orgasm after testosterone treatment and SRS. Almost all participants were able to achieve orgasm during masturbation and sexual intercourse, and the majority reported a change in orgasmic feelings toward a more powerful and shorter orgasm. Surgical satisfaction was high, despite a relatively high complication rate.

Conclusion

Results of the current study indicate transsexual men generally have a good quality of life and experience satisfactory sexual function after SRS.
Sexual Function in Female Patients with Obstructive Sleep Apnea
Authors: Petersen Marian , Kristensen Ellids , Berg Søren , Giraldi Annamaria , Midgren Bengt
Published: June 2011

Introduction

Obstructive sleep apnea is defined as repetitive (≥5/hour) partial or complete cessation of breathing during sleep. Whereas obstructive sleep apnea is often considered to be associated with sexual problems in men, studies concerning effects of obstructive sleep apnea on female sexual function and distress are sparse.

Aim

To investigate sexual dysfunction and sexual distress in female patients with obstructive sleep apnea and to determine which factors are of importance for their sexual function.

Methods

We investigated 80 female patients (ages 28–64) admitted to a sleep laboratory and who after investigation received a diagnosis of obstructive sleep apnea. All subjects answered questions drawn from three self-administered questionnaires on sexuality. The results were compared with a population sample (N = 240).

Main Outcome Measure

Data from nocturnal respiratory recordings. Female Sexual Function Index, Female Sexual Distress Scale and four questions from Life Satisfaction-11 (Lisat-11).

Results

Female Sexual Function Index indicated that obstructive sleep apnea patients were at a higher risk for having sexual difficulties. Female Sexual Distress Scale showed significantly more sexual distress in the obstructive sleep apnea group. Manifest Female Sexual Dysfunction (combined data from Female Sexual Function Index and Female Sexual Distress Scale) showed that female patients with obstructive sleep apnea also had more sexual dysfunction. Severity of sleep apnea was, however, not related to any of these indices but consumption of psychopharmaca was. In Lisat-11, we found that obstructive sleep apnea females scored lower than women in the population sample regarding life as a whole but not regarding domains of closeness.

Conclusions

This study indicates that sexuality of women with untreated obstructive sleep apnea is negatively affected compared with a female population sample. This was not related to severity of obstructive sleep apnea, whereas psychopharmaca may act as an important confounder.
Effect of Periodontitis on Erectile Function and Its Possible Mechanism
Authors: Zuo Zili , Jiang Jun , Jiang Rui , Chen Feng , Liu Junxiang , Yang Haifan , Cheng Yong
Published: June 2011

Introduction

Periodontitis is one of the important risk factors resulting in cardiovascular diseases. Erectile dysfunction (ED) is strongly correlated with cardiovascular diseases. The expression of endothelial nitric oxide synthase (eNOS) in penile tissue has an important role in the mechanism of erection.

Aim

To investigate the effect of periodontitis on erectile function and the possible mechanism.

Methods

After induction of periodontitis in rat, the ratio of maximum intracavernosal pressure/mean arterial pressure (ICPmax/MAP) × 100, the expression of eNOS in penile tissue, the level of serum C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α), and the ultrastructural changes of the cavernous tissue were examined and compared between periodontitis rats (group A) and control rats (group B).

Main Outcome Measure

Periodontitis significantly decrease not only the ICPmax/MAP × 100 and the expression of eNOS but also the activity of NOS and the level of cyclic guanosine monophosphate (cGMP) in cavernous tissue of rat.

Results

After electrostimulation by 3 and 5 voltage, the ratio of ICPmax/MAP × 100 in group A was significantly less than that in group B (19.54 ± 6.16 vs. 30.45 ± 3.12; 30.91 ± 5.61 vs. 50.52 ± 9.52, respectively; P < 0.05).The level of serum CRP and TNF-α in group A is significantly higher in group B (P < 0.05).The quantitative real-time reverse transcription polymerase chain reaction study demonstrated no statistically significant difference in the expression of mRNA of eNOS in cavernous tissue between the two groups (P > 0.05).But there was significant decrease in eNOS protein of the cavernous tissue in group A than in group B (P < 0.05). Total NOS activity and cGMP level in cavernosal tissue were significantly lower in group A than in group B (P < 0.05). There was no significant alternation occurred in the ultrastructures of penile cavernous tissue.

Conclusions

The function of penile erection is impaired by periodontitis. The decreased in the expression of eNOS and NOS activity in penile cavernous tissue caused by mild systemic inflammatory status in periodontitis may be one of the important risk factors of ED.
Relationship Between Erectile Dysfunction and Silent Myocardial Ischemia in Type 2 Diabetic Patients with No Known Macrovascular Complications
Authors: García-Malpartida Katherine , Mármol Rosario , Jover Ana , Gómez-Martínez Manuel J. , Solá-Izquierdo Eva , Victor Victor M. , Rocha Milagros , Sanmiguel Darío , Hernández-Mijares Antonio
Published: June 2011

Introduction

Erectile dysfunction (ED) is associated with cardiovascular disease (CVD) because it is highly prevalent among those with cardiovascular risk factors (CVRFs). Moreover, it precedes the development of CVD and is considered a subrogate marker of subclinical CVD.

Aim

The aim of this study was to evaluate the presence of ED among patients with type 2 diabetes (DM2) without macroangiopathy, and to assess the association between ED and other CVRFs, chronic diabetes complications, silent myocardial ischemia (SMI), and peripheral arterial disease (PAD).

Methods

One hundred fifty-four male patients with DM2 and without clinical evidence of CVD were included in the study. The presence of ED, PAD, SMI, chronic diabetic complications, and other CVRFs was evaluated in these patients.

Main Outcome Measures

PAD; SMI; ED; 24-hour blood pressure Holter; lipid profile; insulin resistance; testosterone; chronic inflammation; nephropathy; retinopathy; neuropathy.

Results

Prevalence of ED was 68.2%. Patients with ED were older and characterized by DM2, systolic blood pressure (BP), retinopathy, and insulin treatment of longer duration than patients without ED, even when adjusting for age was performed. Adjusting for duration of diabetic condition revealed significant differences in age and systolic BP. Independent factors for ED were age (57.7 ± 7.5 years, relative risks [RR 1.1], P = 0.003) and duration of diabetes (9[3–15] years, RR 1.1, P = 0.006). SMI was detected in 13.6% of patients (18.1% in patients with ED vs. 4.1% in patients without ED). Asymptomatic PAD was detected in 13.2% of subjects (14.4% in patients with ED vs. 10.4% in patients without).

Conclusions

ED is highly prevalent in DM2, and is associated with the presence of SMI, higher systolic BP and chronic microvascular diabetic complications.
Determination of trace amounts of β tegafur in commercial α tegafur by powder X-ray diffractometric analysis
Authors: Petkune Sanita , Bobrovs Raitis , Actiņš Andris
Published: June 2011

Objectives

The main objective of this work was to develop a suitable analytical technique for determining trace amounts of the thermodynamically stable solid form in bulk samples of metastable form, to a sensitivity of 0.005%–1.0%. Tegafur (5-fluoro-1-(tetrahydro-2-furyl)-uracil) α and β crystalline forms were used as a model for this problem.

Methods

The trace content of the thermodynamically stable β polymorphic form in tegafur samples was increased by promoting phase transition from the bulk of thermodynamically metastable α form to β form, and achieving sufficient β form content for a quantitative powder X-ray diffractometry (PXRD) analysis. The phase transition was stimulated by adding water to the samples and then grinding in controlled conditions (temperature, time, grinding speed). A calibration line was constructed using the least squares method.

Key findings

By using a solvent that does not form hydrates with the analysed polymorphs, it was possible to promote the phase transformation from metastable form to the thermodynamically stable form. After sample preparation, the thermodynamically stable solid form content in the analysed mixture had increased proportionally to the initial weight fraction (0.005%–1.0%) of the stable form seed crystals in the samples, and the coefficient of proportionality was 43.0 ± 0.9, with a standard deviation Sn = 1.5%.

Conclusions

A simple, sensitive, semi-quantitative analytical method was developed for the low-level determination of the thermodynamically stable polymorphic form in mixtures of thermodynamically stable and metastable polymorphs.
Impact of Time-Resolved Entropy Measurement on a One-and-One-Half-Stage Axial Turbine Performance
Authors: Mansour M. , Chokani N. , Kalfas A. I. , Abhari R. S.
Published: June 2011

An accurate assessment of unsteady interactions in turbines is required, so that this may be taken into account in the design of the turbine. This assessment is required since the efficiency of the turbine is directly related to the contribution of unsteady loss mechanisms. This paper presents unsteady entropy measurements in an axial turbine. The measurements are conducted at the rotor exit of a one–and-one-half-stage unshrouded turbine that is representative of a highly loaded, high-pressure stage of an aero-engine. The unsteady entropy measurements are obtained using a novel miniature fast-response probe, which has been developed at ETH Zurich. The entropy probe has two components: a one-sensor fast-response aerodynamic probe and a pair of thin-film gauges. The probe allows the simultaneous measurement of the total temperature and the total pressure from which the time-resolved entropy field can be derived. The measurements of the time-resolved entropy provide a new insight into the unsteady loss mechanisms that are associated with the unsteady interaction between rotor and stator blade rows. A particular attention is paid to the interaction effects of the stator wake interaction, the secondary flow interaction, and the potential field interaction on the unsteady loss generation at the rotor exit. Furthermore, the impact on the turbine design of quantifying the loss in terms of the entropy loss coefficient, rather than the more familiar pressure loss coefficient, is discussed in detail.
Nonlinear Flutter in Fan Stator Vanes With Time Dependent Fixity
Authors: Srivastava R. , Panovsky J. , Kielb R. , Virgin L. , Ekici K.
Published: June 2011

A new mechanism for fan stator vane failure in turbofan engines at high speed and high loading has been identified and reported in this paper. Highly destructive vane failures have been encountered at Honeywell in a development fan with composite stator vanes. Measured data indicated nonlinear high amplitude vibratory response in fan stator vanes on the stall side of the fan map at high speeds. Analysis showed that under certain steady loading, vane fixity at the hub could change, significantly reducing the vane natural frequency. At this lower natural frequency, the vane was found to be aeroelastically unstable, and calculated response exhibited characteristics similar to those observed during failure. An engine test conducted to validate the role of hub fixity in vane failures showed the failure to be a self-excited phenomenon and not driven by an external source of excitation. It was also shown that failures occur in vanes that are not rigidly fixed, validating the role of hub fixity in vane failures. Test results along with analysis confirm the role of time dependent hub fixity leading to the highly destructive flutter responsible for vane failures.
Experimental Investigation of Endwall and Suction Side Blowing in a Highly Loaded Compressor Stator Cascade
Authors: Nerger Daniel , Saathoff Horst , Radespiel Rolf , Gümmer Volker , Clemen Carsten
Published: June 2011

The following paper describes an experimental investigation of a highly loaded stator cascade with a pitch to chord ratio of t/l=0.6. Experiments without as well as with active flow control by means of endwall and suction side blowing were conducted. Five-hole-probe measurements in pitchwise and spanwise directions as well as endwall oil flow visualizations were carried out in order to determine the performance of the cascade and to analyze the flow phenomena occurring. To quantify the effectivity of the active flow control method, taking the additional energy input into account, corrected losses and an efficiency, which relates the difference of flow power deficit with and without active flow control to the flow power of the blowing jet itself, were evaluated. Even though an increase of static pressure rise could be achieved, a decrease of the total pressure losses was possible for a few operating points only.
Modifications of the Polylactic Acid Surface Properties by DBD Plasma Treatment at Atmospheric Pressure
Authors: Vergne C. , Buchheit O. , Eddoumy F. , Sorrenti E. , Di Martino J. , Ruch D.
Published: June 2011

In this study, nitrogen plasma treatment at atmospheric pressure was used to modify the surface of polylactic acid (PLA), especially its low surface energy and wettability, which do not favor the interface adhesion with another material when blended. The dielectric barrier discharge (DBD) configuration was selected. Treatment time was varied, and induced chemical and topographical surface modifications were assessed. Attention was first focused on the effect of the treatment duration on the hydrophilicity and the topography of PLA. Results showed that plasma treatment enhanced the PLA surface hydrophilicity. The overall surface roughness was also found to be increased. Moreover, both properties rose with increasing treatment time. Thus, according to the Wenzel’s relation, the surface roughening contributed to the enhancement of the PLA hydrophilicity generated by plasma treatment. Then, the chemical surface changes induced by specific plasma activation were studied. Analyses pointed out the incorporation of hydrophilic groups such as nitrogen functional species after treatment. The stability of this treatment under air was also investigated: measurements showed that the hydrophobic recovery mainly occurred the first hours of storage.
Wear Simulation of a Reciprocating Seal
Authors: Békési Nándor , Váradi Károly , Felhős Dávid
Published: June 2011

Modeling of the complex tribological behavior of the elastomer parts is required when designing sliding seal applications. Friction, wear, and lubrication mechanisms of rubber-like materials differ from those in case of metals, ceramics, and rigid polymers; therefore, their modeling also requires other techniques. Tribological behavior of a sliding seal was investigated both experimentally and numerically. In the experimental setup, the counterpart of the seal was pressed and rubbed against the section of the seal in various lubrication conditions. The worn surface of the seal was inspected using white light profilometry. The test configuration was modeled by FEA. A wear algorithm (based on the linear wear theory) with an attached damage analysis was applied to the frictional contact simulation. The nonlinear and time dependent material behavior of the seal was also taken into account. The results of the tribological simulation (in which the internal friction and the effects of damage by rupture of the rubber material were considered) are in good agreement with the results of the surface inspections done on the worn seal specimens. The presented wear simulation technique of deactivating elements is suitable for modeling wear that is larger than the size of the elements in the FE mesh.