bluuebunny/crossref_metadata_2025 huggingface dataset:
Dicaffeoylquinic acids in Yerba mate (Ilex paraguariensis St. Hilaire) inhibit NF‐κB nucleus translocation in macrophages and induce apoptosis by activating caspases‐8 and ‐3 in human colon cancer cells
Authors: Puangpraphant Sirima , Berhow Mark A. , Vermillion Karl , Potts Greg , Gonzalez de Mejia Elvira
Published: June 2011

Scope: The biological functions of caffeoylquinic acid (CQA) derivatives from various plant sources have been partially elucidated. The objectives were to isolate and purify diCQAs from Yerba mate tea leaves and assess their anti‐inflammatory and anti‐cancer capabilities in vitro and explore their mechanism of action.

Methods and results: Methanol extracts of dried mate leaves were resolved by flash chromatography and further purified resulting in two fractions one containing 3,4‐ and 3,5‐diCQAs and the other 4,5‐diCQA with NMR‐confirmed structures. Both fractions inhibited LPS‐induced RAW 264.7 macrophage inflammation by suppressing nitric oxide/inducible nitric oxide and prostaglandin E2/cyclooxygenase‐2 pathways through inhibiting nucleus translocation of Nuclear factor κB subunits, p50 and p65. The diCQA fractions inhibited Human colon cancer cells CRL‐2577 (RKO) and HT‐29 cell proliferation by inducing apoptosis in a time‐ and concentration‐dependent manner, but did not affect the protein levels of p21, p27, p53, and Bax:Bcl‐2 ratio in RKO cells. In HT‐29 cells, however, the diCQA fractions increased Bax:Bcl‐2 ratio. The diCQA fractions increased the activation of caspase‐8 leading to cleavage of caspase‐3 in both RKO and HT‐29 colon cancer cells.

Conclusion: The results suggest that diCQAs in Yerba mate could be potential anti‐cancer agents and could mitigate other diseases also associated with inflammation.
The influence of Cd(ZnO) on the structure, optical and thermal stabilities of polyvinyl chloride nanocomposites
Authors: Mahmoud Waleed E. , Al‐Ghamdi A. A.
Published: June 2011

The doping of nanomaterials into polymers creates novel nanocomposite materials with desired properties. The influence of these nanoscale fillers on the structure and optical and thermal stabilities of polymer are the crucial clue to introduce these novel nanocomposites to service life applications. In this work, cadmium doped zinc oxide (Cd0.5Zn0.5O) nanopowders with a uniform particle size of around 10 nm have been synthesized, purified, and blended with polyvinyl chloride (PVC) by solution mixing to prepare PVC/Cd0.5Zn0.5O nanocomposite films. The structure and morphology of PVC/Cd0.5Zn0.5O nanocomposite films have been characterized using transmission electron microscopy. The results showed that as the amount of nanoscale fillers increases the nanocrystals tend to aggregates and the size of these aggregates increases from 25 to 100 nm. The UV–vis spectra showed that the prepared PVC/Cd0.5Zn0.5O nanocomposite films are highly transparent. The transparency at higher concentrations slightly decreased as a consequence of light scattering due to large aggregates. The thermogravimetric results showed that a small amount of Cd0.5Zn0.5O nanopowders (<0.6 wt%) without further surface modification can greatly improve the thermal stability of PVC. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Rapid Identification of Calotropagenin Glycosides Using High‐Performance Liquid Chromatography Electrospray Ionisation Tandem Mass Spectrometry
Authors: Kanojiya Sanjeev , Madhusudanan K. P.
Published: June 2011

Introduction

Cardiac glycosides in Calotropis procera have therapeutic use as inhibitors of Na+/K+‐ATPase to regulate heart contractions. A large amount of research attention has been received by these compounds towards their identification and structural characterisation. In order to achieve rapid identification of cardiac glycosides in phytochemical extracts a liquid chromatography tandem mass spectrometry (LC‐MS/MS) method has been developed involving metal cationisation by post‐column addition of alkali salts for the unambiguous determination of their molecular weights.

Objective

Identification of cardiac glycosides in Calotropis procera leaf extract.

Results

Calotropagenin and its 10 glycosides were unambiguously identified. The daughter ions at m/z 387, 369, 359, 351, 341 and 323 in their MS/MS spectra were attributed to the calotropagenin aglycone unit.

Conclusion

High performance liquid chromatography in combination with electrospray ionization tandem mass spectrometry involving metal cationisation by post column addition of alkali salts was successfully utilised for the rapid identification of calotropagenin glycosides/derivatives in Calotropis procera extract. Copyright © 2011 John Wiley & Sons, Ltd.
Amniopatch for iatrogenic rupture of the fetal membranes
Authors: Deprest Jan , Emonds Marie‐Paule , Richter Jute , DeKoninck Philip , Van Mieghem Tim , Van Schoubroeck Dominique , Devlieger Roland , De Catte Luc , Lewi Liesbeth
Published: June 2011

With the increased use of invasive fetal procedures, the number of women facing post‐procedure membrane rupture is increasing. Here we review the use of platelets and fresh frozen plasma for sealing iatrogenic fetal membrane defects by describing the mechanisms of action of the amniopatch procedure as well as published experience. In cases of iatrogenic preterm pre‐labour rupture of the membranes, amniopatch effectively seals the fetal membranes in over two‐thirds of cases. There is a risk of 16% of in utero fetal death, which may occur at varying intervals from the procedure and often for unknown reasons. Amniopatch has also been used as a treatment of chorionic membrane separation. In summary, current experience suggests that in cases of early onset but persistent amniotic fluid leakage following an invasive fetal procedure, amniopatch is an option. Copyright © 2011 John Wiley & Sons, Ltd.
NMR investigation of aniline oligomers produced in the oxidation of aniline in alkaline medium
Authors: Kříž Jaroslav , Konyushenko Elena N , Trchová Miroslava , Stejskal Jaroslav
Published: June 2011

The chloroform‐soluble products of aniline or (15N)aniline oxidation in alkaline medium were analysed using one‐ and two‐dimensional 1H NMR, 13C NMR and 15N NMR spectroscopy. Among the products, two were found to be prominent, namely a carbonyl‐containing semiquinonoid and a phenazine‐like structure. The probable mechanism of their formation is suggested. Copyright © 2011 Society of Chemical Industry
Oriented structure in stretched isotactic polypropylene melt and its unexpected recrystallization: optical and X‐ray studies
Authors: Zheng Guoqiang , Jia Zhenhua , Li Songwei , Dai Kun , Liu Baochen , Zhang Xiaoli , Mi Liwei , Liu Chuntai , Chen Jingbo , Shen Changyu , Peng Xiangfang , Li Qian
Published: June 2011

At an extremely small extrusion rate, an isotactic polypropylene melt was extruded through a slit die of an extruder. Simultaneously, the extruded melt was stretched at various stretching rates (SRs) at the die exit. The oriented structure and its subsequent recrystallization via self‐seeding were investigated using polarized optical microscopy, two‐dimensional wide‐angle X‐ray scattering and small‐angle X‐ray scattering. As expected, much slenderer and denser oriented structures were formed at larger SR, which indicates that orientation is preferably promoted with increasing SR. In the case of the crystalline morphology developed during recrystallization, a shish kebab‐like structure was retrieved via the surviving oriented structure after annealing. Unexpectedly, for the sheet stretched at higher SR, a mainly sparse and short shish kebab structure was observed. For the sheet stretched at lower SR, a dense and long shish kebab structure was observed. This suggests that the oriented structure in the sheet stretched at lower SR has a better thermal stability than that in the sheet stretched at higher SR. This is discussed based on the relaxation of entangled junctions in the stretched networks with respect to varying chain length. Copyright © 2011 Society of Chemical Industry
Hartree–Fock and density functional theory study of remote substituent effects on heterolytic Fe―C bond energies of p‐G‐C6H4CH2Fe(CO)2(η5‐C5H5) and p‐G‐C6H4(H)(CN)CFe(CO)2(η5‐C5H5)
Authors: Zeng Qing , Li Zucheng
Published: June 2011

Knowledge of the strength of the metal–ligand bond breaking and formation is fundamental for an understanding of the thermodynamics underlying many important stoichiometric and catalytic organometallic reactions. Quantum chemical calculations at different levels of theory have been used to investigate heterolytic Fe―C bond energies of para‐substituted benzyldicarbonyl(η5‐cyclopentadienyl)iron, p‐G‐C6H4CH2Fp [1, G = NO2, CN, COMe, CO2Me, CF3, Br, Cl, F, H, Me, MeO, NMe2; Fp = (η5‐C5H5)(CO)2Fe], and para‐substituted α‐cyanobenzyldicarbonyl(η5‐cyclopentadienyl)iron, p‐G‐PANFp [2, PAN = C6H4CH(CN)]. The results show that BP86 and TPSSTPSS can provide the best price/performance ratio and more accurate predictions in the study of ΔHhet(Fe―C)'s. The good linear correlations [r = 0.98 (g, 1a), 0.99 (g, 2b)] between the substituent effects of heterolytic Fe―C bond energies [ΔΔHhet(Fe―C)'s] of series 1 and 2 and the differences of acidic dissociation constants (ΔpKa) of C―H bonds of p‐G‐C6H4CH3 and p‐G‐C6H4CH2CN imply that the governing structural factors for these bond scissions are similar. And the excellent linear correlations [r = −1.00 (g, 1c), −0.99 (g, 2d)] between ΔΔHhet(Fe―C)'s and the substituent σp− constants show that these correlations are in accordance with Hammett linear free energy relationships. The polar effects of these substituents and the basis set effects influence the accuracy of ΔHhet(Fe―C)'s. ΔΔHhet(Fe―C)'s(1, 2) follow the Capto‐dative Principle. The detailed knowledge of the factors that determine the Fp―C bond strengths would greatly aid in understanding reactivity patterns in many processes. Copyright © 2011 John Wiley & Sons, Ltd.
Low‐bandgap donor–acceptor copolymers with 4,6‐bis(3′‐(2‐ethylhexyl)thien‐2′‐yl)thieno[3,4‐c][1,2,5]thiadiazole: synthesis, optical, electrochemical, and photovoltaic properties
Authors: Cimrová Věra , Kmínek Ivan , Pavlačková Petra , Výprachtický Drahomír
Published: June 2011

Two new low‐bandgap alternating copolymers (CEHTF and CEHTP) consisting of 4,6‐bis(3′‐(2‐ethylhexyl)thien‐2′‐yl)thieno[3,4‐c][1,2,5] thiadiazole and 9,9‐bis(2‐ethylhexyl)fluorene or 2,5‐bis(isopentyloxy)benzene were synthesized by Suzuki coupling reaction of corresponding comonomers. Their optical, electrochemical, and photovoltaic (PV) properties were studied and are reported. Both the copolymers exhibited long‐wavelength absorption covering the whole visible spectral region, which is in CEHTP thin films extended up to near infrared region, ambipolar redox properties, and electrochromism. High‐electron affinities and low‐optical bandgap values, 1.37 and 1.15 eV, were determined for CEHTF and CEHTP, respectively. PV devices with bulk heterojunction made of blends of copolymers and fullerene derivative [6,6]‐phenyl‐C61‐butyric acid methyl ester ([60]PCBM) were prepared and characterized. Effects of intramolecular charge transfer strength and side‐chain nature and length on photophysical properties are discussed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Pyrenylamine‐functionalized aromatic polyamides as efficient blue‐emitters and multicolored electrochromic materials
Authors: Kung Yi‐Chun , Hsiao Sheng‐Huei
Published: June 2011

A series of novel aromatic polyamides with pyrenylamine in the backbone were prepared from a newly synthesized dicarboxylic acid monomer, N,N‐di(4‐carboxyphenyl)‐1‐aminopyrene, and various aromatic diamines via the phosphorylation polyamidation technique. These polyamides were readily soluble in many organic solvents and could be solution‐cast into tough and amorphous films. They had useful levels of thermal stability with glass‐transition temperatures in the range of 276–342 °C and 10% weight loss temperatures in excess of 500 °C. The dilute N‐methyl‐2‐pyrrolidone (NMP) solutions of these polymers exhibited fluorescence maxima around 455–540 nm with quantum yields up to 56.9%. The polyamides also showed remarkable solvatochromism of the emission spectra. Their films showed reversible electrochemical oxidation and reduction accompanied by strong color changes from colorless neutral state to purple oxidized state and to yellow reduced state. The polyamide 4g containing the pyrenylamine units in both diacid and diamine sides exhibited easily accessible p‐ and n‐doped states, together with multicolored electrochromic behaviors. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and fluorescent properties of model compounds for conjugated polymer containing maleimide units at the main chain
Authors: Onimura Kenjiro , Matsushima Mieko , Nakamura Munetoshi , Tominaga Tatsuya , Yamabuki Kazuhiro , Oishi Tsutomu
Published: June 2011

2,3‐Diaryl substituted maleimides as model compounds of conjugated maleimide polymers [poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar)] were synthesized from 2,3‐dibromo‐N‐substituted maleimide (DBrRMI) [R= cyclohexyl (DBrCHMI) and n‐hexyl (DBrHMI)] and aryl boronic acid using palladium catalysts. To clarify structures of conjugated polymer containing maleimide units at the main chain, 13C NMR spectra of 2‐aryl or 2,3‐diaryl substituted maleimides were compared with those of N‐substituted maleimide polymers. Copolymers obtained with DBrRMI via Suzuki‐Miyaura cross‐coupling polymerizations or Yamamoto coupling polymerizations were dehalogenated structures at the terminal end. This dehalogenation may contribute to the low polymerizability of DBrRMIs. On the other hand, the π‐conjugated compounds showed high solubility in common organic solvents. The N‐substituents of maleimide cannot significantly affect the photoluminescence spectra of 2,3‐diaryl substituted maleimides derivatives. The fluorescence spectra of poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar) varied with N‐substituents of the maleimide ring. When exposed to ultraviolet light of wavelength 352 nm, a series of 1,4‐phenylene‐ and/or 2,5‐thienylene‐based copolymers containing N‐substituted maleimide derivatives fluoresced in a yellow to blue color. It was found that photoluminescence emissions and electronic state of π‐conjugated maleimide derivatives were controlled by aryl‐ and N‐substituents, and maleimide sequences of copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
ATRP of MMA under 60Co γ‐irradiation at room temperature
Authors: Chen Qifeng , Zhang Zhengbiao , Zhou Nianchen , Cheng Zhenping , Zhu Jian , Zhang Wei , Zhu Xiulin
Published: June 2011

In this work, atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was successfully carried out at room temperature (25 °C) under 60Co γ‐irradiation environment. The polymerization proceeded smoothly with high conversion (>90%) within 7 h. The polymerizations kept the features of controlled radical polymerization: first‐order kinetics, well‐predetermined number‐average molecular weights (Mn,GPC), and narrow molecular weight distributions (Mw/Mn < 1.25). 1H NMR spectroscope and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry confirmed that poly(methyl methacrylate) (PMMA) chain was end‐capped by the initiator moieties. The Cu(II) concentration could reduce to 20 ppm level while keeping good control over molecular weights. This is the first successful example for the ATRP of MMA under 60Co γ‐irradiation at room temperature. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Estimation of Possible Mechanisms of Escherichia coli Inactivation by Plasma Treated Sodium Chloride Solution
Authors: Oehmigen Katrin , Winter Jörn , Hähnel Marcel , Wilke Christian , Brandenburg R. , Weltmann Klaus‐Dieter , von Woedtke Thomas
Published: June 2011

Treatment of aqueous liquids by surface‐DBD in atmospheric air resulted in bactericidal activity of the liquid itself. A 7 min treatment of sodium chloride (NaCl) solution and its immediate addition to Escherichia coli resulted in a complete bacteria inactivation (≥7 log) after 15 min exposure time. With a 30 min delay between plasma treatment of liquid and its addition to the bacteria, bactericidal effect was reduced but still detectable. Nitrate (${\rm NO}_{2}^{{-} } $), nitrite (${\rm NO}_{2}^{{-} } $), and hydrogen peroxide (H2O2), respectively, as well as strong acidification are detected in plasma treated liquids and can explain this bactericidal activity partially. Combination of 1.5 mg · L−1 ${\rm NO}_{2}^{{-} } $ and 2.5 mg · L−1 H2O2 at pH 3 results in maximum 3.5 log E. coli reduction within 60 min. Plasma diagnostics and liquid analytics are combined with theoretical considerations to focus possible reaction channels of plasma–water interactions. Using FT‐IR, stable molecules like nitrous oxide (N2O), ozone (O3), carbon dioxide (CO2), and traces of nitric acid (HNO3) and/or peroxynitrous acid (ONOOH) were measured. Reactions of these molecules from the plasma/gas phase with the aqueous liquid can result in acidification and generation of H2O2, ${\rm NO}_{2}^{{-} } $, and ${\rm NO}_{3}^{{-} } $ or peroxynitrite (ONOO−), respectively, via reactions which are associated with the occurrence of several more or less stable but biologically active chemical intermediates like ${\rm NO}^{ \bullet } $ or nitrogen dioxide (${\rm NO}_{2}^{ \bullet } $). On the other hand, H2O2, ${\rm NO}_{2}^{{-} } $, and ${\rm NO}_{3}^{{-} } $/ONOO− could serve as starting reaction partners to generate ${\rm NO}^{ \bullet } $, ${\rm HO}^{ \bullet } $, ${\rm NO}_{2}^{ \bullet } $, or hydroxyl radicals (${\rm HOO}^{ \bullet } $) in the liquid.
Adenosine induces cell‐cycle arrest and apoptosis in androgen‐dependent and ‐independent prostate cancer cell lines, LNcap‐FGC‐10, DU‐145, and PC3
Authors: Aghaei Mahmoud , Karami‐Tehrani Fatemeh , Panjehpour Mojtaba , Salami Siamak , Fallahian Faranak
Published: June 2011

BACKGROUND

Adenosine has been shown to inhibit cell growth and induce apoptosis in the several cancer cells via intrinsic and extrinsic pathway. The present study was designed to understand the mechanism underlying adenosine‐induced apoptosis in the DU‐145, PC3, and LNcap‐FGC10 human prostate cancer cells.

METHODS

To observe cell viability and proliferation, MTT assay, cell counting, and BrdU assay were carried out in DU‐145, PC3, and LNcap‐FGC10 cells. Apoptosis was assessed with the analysis of cell cycle, Hoechst 33258 staining, propidium iodide and annexin‐V staining, reactive oxygen species (ROS) formation, mitochondrial membrane potential (ΔΨM) measurement, caspase‐3 activity assay, Bcl‐2 and Bax protein expression. Moreover, the expression of adenosine receptors and the effects of adenosine receptor (A1, A2a, and A3) antagonists were examined.

RESULT

Adenosine significantly reduced cell proliferation in a dose‐dependent manner in DU‐145, PC3, and LNcap‐FGC10 cell lines. Adenosine induced arrest in the cell‐cycle progression in G0/G1 phase through Cdk4/cyclinD1‐mediated pathway. Adenosine induced apoptosis, which was determined by morphological changes and increased sub‐G1 population. Furthermore, increase of ROS, loss of MMP, activation of caspase‐3, and down‐regulation of Bcl‐2 expression was observed. A1, A2a, A2b, and A3 adenosine receptors mRNA are expressed in the cell lines. Moreover, adenosine‐induced apoptosis was inhibited by MRS1220, A3 adenosine receptor antagonist.

CONCLUSION

Our results suggest that adenosine induced apoptosis in prostate cancer cells via the mitochondrial pathway and is related to the adenosine receptors. These data might suggest that adenosine could be used as an agent for the treatment of prostate cancer. Prostate 72:361–375, 2012. © 2011 Wiley Periodicals, Inc.
Aryldiones incorporating a [1,4,5]oxadiazepane ring. Part 2: Chemistry and biology of the cereal herbicide pinoxaden
Authors: Muehlebach Michel , Cederbaum Fredrik , Cornes Derek , Friedmann Adrian A , Glock Jutta , Hall Gavin , Indolese Adriano F , Kloer Daniel P , Le Goupil Gael , Maetzke Thomas , Meier Hans , Schneider Rudolf , Stoller André , Szczepanski Henry , Wendeborn Sebastian , Widmer Hansjuerg
Published: June 2011

BACKGROUND: Pinoxaden is a new cereal herbicide that provides outstanding levels of post‐emergence activity against a broad spectrum of grass weed species for worldwide selective use in both wheat and barley.

RESULTS: Factors influencing activity and tolerance to pinoxaden were in part linked to distinct structural parts of the active ingredient. Three complementary contributions that decisively impact upon the herbicidal potency against grasses were identified: a preferred 2,6‐diethyl‐4‐methyl aromatic substitution pattern, a dione area suitable for proherbicide formation and beneficial adjuvant effects. The uptake and translocation pattern of pinoxaden when coapplied with its tailored adjuvant were analysed by autoradiography, indicating extensive and rapid penetration, followed by effective distribution throughout the plant. Crop injury reduction on incorporation of the [1,4,5]oxadiazepane ring into the aryldione template was reinforced with safener technology. Comparative studies on the behaviour of pinoxaden applied either alone or in combination with the safener cloquintocet‐mexyl demonstrated that addition of the safener resulted in significant enhancement of metabolic degradation in wheat and barley, providing excellent crop tolerance and a substantial selectivity margin without adverse effects on weed control.

CONCLUSION: The biological potential of pinoxaden and its active principle pinoxaden dione in terms of grass weed control and tolerance in cereals was fully exploited by inclusion of the safener cloquintocet‐mexyl in the formulation in combination with a specific and tailor‐made tank‐mix adjuvant based on methylated rape seed oil. Copyright © 2011 Society of Chemical Industry
The phytotoxicity of natural tetramic acid derivatives
Authors: Zhao Huaping , Cui Zhipeng , Gu Yucheng , Liu Yuxiu , Wang Qingmin
Published: June 2011

Natural tetramic acid derivatives have attracted a great deal of interest of chemists because of their structural features and the broad range of biological activities. This paper focuses on five naturally occurring tetramic acid derivatives reported to have phytotoxicity and discusses their common structural characteristics. Copyright © 2011 Society of Chemical Industry
Esterase inhibition by synergists in the western flower thrips Frankliniella occidentalis
Authors: López‐Soler Neus , Cervera Amelia , Quinto Vicente , Abellán Jaime , Bielza Pablo , Martínez‐Pardo Rafael , Garcerá Maria Dolores
Published: June 2011

BACKGROUND: Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is among the most important crop pests in the south‐eastern region of Spain. Its increasing resistance to insecticides constitutes a serious problem, and understanding the mechanisms involved is therefore of great interest. Use of synergists to inhibit the enzymes involved in insecticide detoxification is widely used to determine their responsibility for insecticide resistance. However, they do not always act as intended or expected, and caution must be exercised when interpreting synergist results.

RESULTS: Laboratory‐selected strains of WFT were used to analyse the effects of the synergists piperonyl butoxide (PBO), S,S,S‐tributyl phosphorotrithioate (DEF) and methiocarb on total esterase activity. Significant differences were found, indicating esterase activity inhibition by DEF, a lower effect for methiocarb and a small inhibition of the activity by PBO. Esterase isoenzyme inhibition by these compounds showed a similar result; this assay revealed an extreme sensitivity of Triplet A (resistance‐associated esterases) to DEF. In an in vivo assay carried out with these compounds at different incubation times, only DEF caused posterior in vitro esterase activity inhibition, with a maximum effect 1 h after treatment.

CONCLUSION: In this work, only DEF shows true synergistic inhibition of WFT esterases. Copyright © 2011 Society of Chemical Industry
Traps and defects in pre‐ and post‐ stressed AlGaN–GaN high electron mobility transistors
Authors: Sin Yongkun , Foran Brendan , Joh Jungwoo , del Alamo Jesus A.
Published: June 2011

We used deep level transient spectroscopy (DLTS) and HR‐TEM techniques to study traps and defects in pre‐ and post‐stressed AlGaN/GaN high electron mobility transistors (HEMTs) grown by MOCVD on semi‐insulating SiC substrates. DLTS identified two dominant traps with activation energies of 0.5 and 0.7 eV in both pre‐ and post‐stressed GaN HEMTs. Electrical stress resulted in a significant increase in the density of 0.5 eV traps. This is attributed to point defects (most likely N antisites) in the AlGaN barrier and clearly suggests that these traps play a critical role in degradation of the devices. Cross‐sectional TEM confirmed physical damage on the edge of the gate that was likely due to the inverse piezoelectric effect.
Low resistance Mo/Al/Mo/Au ohmic contact scheme to InAlN/AlN/GaN heterostructure
Authors: Lee Jaesun , Yan Minjun , Ofuonye Benedict , Jang Jaehyung , Gao X. , Guo Shiping , Adesida Ilesanmi
Published: June 2011

Mo/Al/Mo/Au metallization scheme was investigated to develop low‐resistance ohmic contacts on InAlN/AlN/GaN field‐effect transistor heterostructure using a pre‐metallization surface treatment with SiCl4 plasma in a reactive ion etching system and a relatively low‐temperature anneal at 650 °C. The contact resistance and specific contact resistivity were dramatically improved to as low as 0.15 Ω mm and 7.8 × 10−7 Ω cm2 at 650 °C, respectively.
Ridge‐type AlGaInN‐based laser diode structure by selective regrowth
Authors: Zhao Wei , Detchprohm Theeradetch , Hou Wenting , Li Yufeng , Wetzel Christian
Published: June 2011

We report the development of a novel ridge‐type AlGaInN‐based laser diode structure fabricated by a metal organic vapor phase epitaxial regrowth method. The selective‐area regrowth of AlGaN was optimized and compared with regular planar growth. An AlN fraction of 13% in the regrown ridge was concluded from the cathodoluminescence spectrum. The laser diode structure showed superluminescence at 465 nm under optical excitation. Under electrical excitation a super‐linear increase of the light output power was observed.
Theoretical study on pressure‐induced phase transition and thermal properties of HgAl2Se4
Authors: Verma Udai Pratap , Singh Poonam , Jensen Per
Published: June 2011

The structural, electronic, and thermal properties of mercury selenoaluminate; a defect chalcopyrite compound has been studied by the first principle approach. HgAl2Se4 is a ternary semiconducting compound, crystallizes in defect chalcopyrite structure within I‐4 space group at ambient conditions. A pressure‐induced structural phase transition from body‐centered tetragonal (BCT) to spinel phase has been confirmed. The lattice constants, equilibrium volume, bulk modulus, and its pressure derivative for both phases are found to be in excellent agreement with the available experimental results. The structural and electronic properties of spinel phase are reported for the first time. The quasiharmonic Debye model is applied to study the thermal and vibrational effects for the stable BCT phase. Thermal parameters such as Grüneisen parameter, Debye temperature, specific heat, etc., have been determined as a function of pressure and temperature. Reported results will simulate further interest in theoretical and experimental research in the emerging field of optoelectronics.
Microphotoluminescence studies on GaN‐based airpost pillar microcavities containing InGaN quantum wells and quantum dots
Authors: Sebald Kathrin , Lohmeyer Henning , Kalden Joachim , Seyfried Moritz , Figge Stephan , Kruse Carsten , Dartsch Heiko , Tessarek Christian , Hommel Detlef , Gutowski Jürgen
Published: June 2011

We report on the optical properties of monolithic GaN‐based airpost pillar microcavities (MCs) with embedded InGaN quantum wells or quantum dots (QDs), respectively. The presented MCs are designed by use of different kinds of distributed Bragg reflectors consisting of either AlGaN/GaN, AlInN/GaN, or superlattices of AlN/InGaN and GaN. A quality factor of up to Q = 260 has been achieved. Airpost pillar MCs, providing a three‐dimensional optical confinement, are realized by focused ion beam etching starting from an all‐epitaxially grown vertical‐cavity surface‐emitting laser structure. Pillar diameters below 1 µm are well controllable. The sidewalls are smooth and show a damaged surface layer of a thickness less than 2 nm only. Microphotoluminescence (µ‐PL) measurements reveal the longitudinal and transversal mode spectra of the cavities in good agreement with theoretical calculations based on a vectorial transfer‐matrix method. Furthermore, the spectra of the QD based samples reveal distinct spectrally sharp emission lines around 2.73 eV which can be attributed to the emission of single‐InGaN QDs and traced up to 120 K.

magnified image

Scanning electron micrograph of a GaN‐based airpost pillar superimposed by the µ‐PL spectrum of a pillar with a diameter of d = 1.8 µm. The measurement performed at T = 150 K reveals the discrete resonator modes.
A novel fabrication method of CNT‐CP composite single nanowires self‐templated by dielectrophoresis and electropolymerization
Authors: An Taechang , Choi WooSeok , Joo Sang Woo , Lim Geunbae
Published: June 2011

A new method for fabricating carbon nanotube‐conducting polymer (CNT‐CP) composite single nanowires is reported. The method developed is highly efficient, reliable, and economical because it obviates the time consuming process of template fabrication and the post‐synthesis task of positioning nanowires. Single nanowires with diameters of 50‐500 nm are fabricated between electrodes, self‐templated by dielectrophoresis and electropolymerization. Fabrication of an individually addressed nanowire array with cantilever electrodes on a microchip is demonstrated.

magnified image

SEM images of CNT‐CP composite single nanowires. Scale bar is 2 µm.

(© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antimycobacterial and Synergistic Effects of 18β‐Glycyrrhetinic Acid or Glycyrrhetinic acid‐30‐piperazine in Combination with Isoniazid, Rifampicin or Streptomycin against Mycobacterium bovis
Authors: Zhou Xuezhang , Zhao Li , Liu Xiaoming , Li Xueqiang , Jia Fang , Zhang Yuyan , Wang Yujiong
Published: June 2011

18ß‐Glycyrrhetinic acid (18ßGA) is a major bioactive component of liquorice with known activity. In this study, we found that both 18ßGA and its derivative glycyrrhetinic acid‐30‐piperazine (PGA), have potent antimycobacterial properties against the drug‐susceptible and drug‐resistant Mycobacterium bovis. More importantly, they exhibited synergistic effects with the first‐line drugs isoniazid (INH), rifampicin (RIF) and streptomycin (SM) against clinical M. bovis isolates, including drug‐resistant strains. In combination with a subinhibitory concentration of 18ßGA, the minimum inhibitory concentrations (MICs) of the anti‐tuberculosis agents decreased, ranging from 4‐ to 16‐, 4‐ to 8‐ and 4‐ to 8‐fold for INH (fractional inhibitory concentration index (FICI) 0.125–0.375), RIF (FICI 0.118–0.281) and SM (FICI 0.094–0.275), respectively. In the presence of PGA, MICs for the first‐line agents resulted in a 4–16‐fold decrease for INH (FICI 0.094–0.266, RIF (FICI 0.114–0.313) and SM (FICI 0.094–0.281). Additionally, the MICs of 18ßGA or PGA alone showed significant decreases ranging from 8‐ to 16‐, 8‐ to 64‐ and 8‐ to 128‐fold in the presence of INH, RIF and SM, respectively. These findings indicate that 18ßGA and its derivatives might serve as potential therapeutic compounds for future antimycobacterial drug development. Copyright © 2011 John Wiley & Sons, Ltd.
Direct Manipulation of a Single Potassium Channel Gate with an Atomic Force Microscope Probe
Authors: Kitta Mitsunori , Ide Toru , Hirano Minako , Tanaka Hiroyuki , Yanagida Toshio , Kawai Tomoji
Published: June 2011

Ion channels are membrane proteins that regulate cell functions by controlling the ion permeability of cell membranes. An ion channel contains an ion‐selective pore that permeates ions and a sensor that senses a specific stimulus such as ligand binding to regulate the permeability. The detailed molecular mechanisms of this regulation, or gating, are unknown. Gating is thought to occur from conformational changes in the sensor domain in response to the stimulus, which results in opening the gate to permit ion conduction. Using an atomic force microscope and artificial bilayer system, a mechanical stimulus is applied to a potassium channel, and its gating is monitored in real time. The channel‐open probability increases greatly when pushing the cytoplasmic domain toward the membrane. This result shows that a mechanical stimulus at the cytoplasmic domain causes changes in the gating and is the first to show direct evidence of coupling between conformational changes in the cytoplasmic domain and channel gating. This novel technology has the potential to be a powerful tool for investigating the activation dynamics in channel proteins.
Measurement of Mass Transfer during Dip‐Pen Nanolithography with Phospholipids
Authors: Biswas Soma , Hirtz Michael , Fuchs Harald
Published: June 2011

Dip‐pen nanolithography (DPN) has been extensively used before for patterning surfaces; however a complete understanding of the ink transport mechanisms is still lacking. Moreover, quality control of the fabricated structures is a bottleneck in DPN fabrication, and one aspect of this is the quantification of the ink mass transfer to the substrate during the lithographic process. There is a demand for measuring the exact amount of molecules deposited on a surface by lithographic methods, especially for biological applications. This article demonstrates a quantitative method for measuring the amount of ink transferred onto the substrate in DPN with phospholipids by dynamic force spectroscopy. To achieve this, the harmonic oscillation of a microcantilever in an atomic force microscope is used, obtaining picogram mass sensitivity in the determination of mass deposition.
A component‐based middleware platform for reconfigurable service‐oriented architectures
Authors: Seinturier Lionel , Merle Philippe , Rouvoy Romain , Romero Daniel , Schiavoni Valerio , Stefani Jean‐Bernard
Published: June 2011

ThetextitService Component Architecture (SCA) is a technology‐independent standard for developing distributed Service‐oriented Architectures (SOA). The SCA standard promotes the use of components and architecture descriptors, and mostly covers the lifecycle steps of implementation and deployment. Unfortunately, SCA does not address the governance of SCA applications and provides no support for the maintenance of deployed components. This article covers this issue and introduces the FRASCATI platform, a run‐time support for SCA with dynamic reconfiguration capabilities and run‐time management features. This article presents the internal component‐based architecture of the FRASCATI platform, and highlights its key features. The component‐based design of the FRASCATI platform introduces many degrees of flexibility and configurability in the platform itself and it can host the SOA applications. This article reports on micro‐benchmarks highlighting that run‐time manageability in the FRASCATI platform does not decrease its performance when compared with the de facto reference SCA implementation: Apache TUSCANY. Finally, a smart home scenario illustrates the extension capabilities and the various reconfigurations of the FRASCATI platform. Copyright © 2011 John Wiley & Sons, Ltd.
Three‐dimensional ultrasonographic assessment of compression effect on urethra following tension‐free vaginal tape and transobturator tape procedures
Authors: Lin K.‐L. , Juan Y.‐S. , Lo T.‐S. , Liu C.‐M. , Tsai E.‐M. , Long C.‐Y.
Published: June 2011

Objective

To compare the anatomical difference using three‐dimensional (3D) ultrasound between the urethra at rest and during straining, in women who have undergone a tension‐free vaginal tape (TVT) or TVT‐obturator tape (TVT‐O) procedure for stress urinary incontinence (SUI).

Methods

We reviewed retrospectively 48 women with SUI who had undergone either a TVT (n = 24) or a TVT‐O (n = 24) procedure. All women underwent urinalysis, pelvic examination, pad test, 3D perineal ultrasonography and personal interview about urinary symptoms within 1 year after surgery.

Results

After both TVT and TVT‐O procedures, the area and longest and shortest diameters of the hypoechoic core of the mid‐urethra were significantly smaller during straining than during resting (P < 0.01). The distance between tape and urethra was similarly smaller during straining in both groups. Analysis of ultrasound measurements in women reporting success (n = 40) and those reporting failure (n = 8) of the procedure showed the area and longest and shortest diameters of the hypoechoic core of the mid‐urethra to be significantly smaller during straining than during resting in both groups (P < 0.01). However, the shortest diameter of the proximal and distal urethra during straining were significantly smaller only in the successful group (P < 0.01).

Conclusion

There are differences in urethral morphology during straining compared with during resting in women with TVT and those with TVT‐O, regardless of tape procedure. A urethral compression effect of slings may have an important role in the continence mechanism. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Comparison of transvaginal sonography and double‐contrast barium enema for diagnosing deep infiltrating endometriosis of the posterior compartment
Authors: Savelli L. , Manuzzi L. , Coe M. , Mabrouk M. , Di Donato N. , Venturoli S. , Seracchioli R.
Published: June 2011

Objectives

To compare the diagnostic accuracy of transvaginal sonography (TVS) and double‐contrast barium enema (DCBE) in the preoperative detection of deep infiltrating endometriosis (DIE) of the posterior compartment.

Methods

This was a prospective study of 69 consecutive patients with results of pelvic examination or symptoms suggestive of DIE of the posterior compartment. TVS and DCBE were performed before surgery by two groups of physicians specialized in endometriosis, each blinded to the results of the other technique. Imaging data were compared with histopathologic analysis of the resected specimen (gold standard). Sensitivity, specificity, positive and negative predictive values and test accuracies were calculated for both imaging modalities.

Results

Sixty seven of the 69 women had a nodule of DIE confirmed at laparoscopy and histopathologic examination. TVS diagnosed DIE in 57 (85%) of these patients, while DCBE revealed the presence of the lesion in 24 (36%) women. For the diagnosis of posterior DIE, TVS and DCBE had, respectively, a sensitivity of 85% and 36%, specificity of 100% and 100%, positive predictive value of 100% and 100%, negative predictive value of 17% and 4% and accuracy of 85.5% and 38%. In patients with pure bowel DIE the sensitivity was 91% and 43%, specificity was 100% and 100%, positive predictive value was 100% and 100%, negative predictive value was 29% and 6% and accuracy was 91% and 45%, respectively.

Conclusions

TVS has a much higher sensitivity than does DCBE in detecting the presence of posterior DIE and should thus be regarded as the imaging modality of choice when there is clinical suspicion of the disease. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Generalized linear models
Authors: Neuhaus John , McCulloch Charles
Published: June 2011

The class of generalized linear models (GLMs) extends the classical linear model for continuous, normal responses to describe the relationship between one or more predictor variablesx1,…,xpand a wide variety of nonnormally distributed responsesYincluding binary, count, and positive‐valued variates. GLMs expand the class of response densities from the normal to an exponential family that contains the normal, Poisson, binomial, and other popular distributions as special cases. The models produce estimated expected values that conform to response constraints and allow nonlinear relationships between predictors and expected values. It is straightforward to construct the likelihood for a set of data so that maximum likelihood and related likelihood‐based methods are popular techniques for parameter estimation and inference. A key point with GLMs is that many of the considerations in model construction are the same as for standard linear regression models as the models have many common features.WIREs Comp Stat2011 3 407–413 DOI: 10.1002/wics.175

This article is categorized under:

Statistical Models > Generalized Linear Models
Correlates of Homeless Episodes Among Indigenous People
Authors: Whitbeck Les B. , Crawford Devan M. , Sittner Hartshorn Kelley J.
Published: June 2011

This study reports the correlates of homeless episodes among 873 Indigenous adults who are part of an ongoing longitudinal study on four reservations in the Northern Midwest and four Canadian First Nation reserves. Descriptive analyses depict differences between those who have and have not experienced an episode of homelessness in their lifetimes. Multivariate analyses assess factors associated with a history of homeless episodes at the time of their first interview and differentiate correlates of “near homelessness” (i.e., doubling up) and “homeless episodes” (periods of actual homelessness). Results show that individuals with a history of homeless episodes had significantly more individual and family health, mental health, and substance abuse problems. Periods of homelessness also were associated with financial problems. Among the female caretakers who experienced episodes of homelessness over the course of the study, the majority had been homeless at least once prior to the start of the study and approximately one‐fifth met criteria for lifetime alcohol dependence, drug abuse, or major depression. Family adversity during childhood was also common for women experiencing homelessness during the study.
Systems of Care: The Story Behind the Numbers
Authors: Brashears Freda , Davis Cliff , Katz-Leavy Judith
Published: June 2011

This article presents a brief description of a longitudinal study of system‐level change, offers observations about what has been learned about the evolution of systems of care from the unique and qualified perspectives of the group of site visitors who gathered the data for the study, and identifies a set of issues that needs to be addressed to advance the system of care model in community based care of children and youth with behavioral health needs and their families. The article describes the system of care assessment portion of the national evaluation of the Federal Children's Mental Health Initiative and presents a brief summary of accumulated findings from the assessments conducted in communities funded in six successive waves of awards to provide context for the site visitors’ observations and the authors’ recommendations. The authors draw upon the expert observations of the site visitors, who represent many different disciplines and backgrounds, which suggest that, as a set of guiding principles, the system of care philosophy and approach seem to have become accepted standards of program practice and system operation in the funded sites, although implementation is uneven across principles and sites. The article concludes with the authors’ identification of high‐level system issues that must be addressed more effectively if systems of care are to come to scale.
Exploratory Bi-Factor Analysis
Authors: Jennrich Robert I. , Bentler Peter M.
Published: June 2011

Bi-factor analysis is a form of confirmatory factor analysis originally introduced by Holzinger. The bi-factor model has a general factor and a number of group factors. The purpose of this article is to introduce an exploratory form of bi-factor analysis. An advantage of using exploratory bi-factor analysis is that one need not provide a specific bi-factor model a priori. The result of an exploratory bi-factor analysis, however, can be used as an aid in defining a specific bi-factor model. Our exploratory bi-factor analysis is simply exploratory factor analysis using a bi-factor rotation criterion. This is a criterion designed to approximate perfect cluster structure in all but the first column of a rotated loading matrix. Examples are given to show how exploratory bi-factor analysis can be used with ideal and real data. The relation of exploratory bi-factor analysis to the Schmid–Leiman method is discussed.
Perceived parental psychological control and adolescent depressive experiences: A cross‐cultural study with Belgian and South‐Korean adolescents
Authors: Soenens Bart , Park Seong‐Yeon , Vansteenkiste Maarten , Mouratidis Athanasios
Published: June 2011

In recent research on psychologically controlling parenting, debate has arisen about the cross‐cultural relevance of this construct, with some scholars arguing that the developmental outcomes of psychological control are culture‐bound and others arguing that the detrimental effects of psychological control generalize across cultures. This study aimed to add to this debate by examining the relevance of a distinction between two domain‐specific expressions of psychological control (i.e., dependency‐oriented and achievement‐oriented) in Belgian (N = 290) and South‐Korean (N = 321) adolescents. Multi‐group path analyses showed that associations between the domains of psychological control, depressive personality, and depressive symptoms were similar between the two samples. Overall, the findings are in line with the notion that the effects of psychological control generalize across culture.
Specialized multimodal outpatient treatment for children with chronic pain: Treatment pathways and long‐term outcome
Authors: Hechlerl Tanja , Martinl Annick , Blankenburgl Markus , Schroederl Sandra , Kosfelderl Joachim , Hölscherl Lisa , Deneckel Heide , Zernikowl Boris
Published: June 2011

Objective: Despite the increased recognition of paediatric chronic pain, centres for providing appropriate treatment are scarce, and much remains unknown about optimal treatment approaches. The purpose of this study was to investigate effectiveness of multimodal outpatient treatment (MOT) through the examination of treatment pathways and long‐term outcomes.

Methods: Within an observational longitudinal study, 275 children (4–18 years) formed the study group and received MOT. Over a 12‐month period, we followed the progress of the study group to identify how many children completed treatment, how many continued treatment and how many were stepped‐up to more intensive treatment. To investigate significant and clinically relevant changes in primary and secondary outcomes the study group was assessed at three consecutive treatment sessions (initial session, 3‐, 6‐month visit) and 12 months following the initial session.

Results: Analysis of treatment pathways showed that 1/3 of the children did not attend the prescribed second and third visit to the clinic. Cessation of treatment correlated with significant improvement. Only a small number of children were still in treatment at 12‐month follow‐up (12%) or needed more intensive treatment (11%). At 12‐month follow‐up, almost 70% of children in the study group were able to attend school regularly. Pain intensity, pain‐related disability and inappropriate coping strategies were significantly reduced at 3‐month visit and remained stable at the subsequent time points.

Conclusions: MOT appears to be beneficial for children with chronic pain. A short intensive intervention (comprising of a total of 2.5‐h) can lead to substantial improvements even for severely affected children.