bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative assessment of cardiac output and left ventricular function by noninvasive phase‐contrast and cine MRI: Validation study with invasive pressure‐volume loop analysis in a swine model
Authors: Lin Hung‐Yu , Freed Darren , Lee Trevor W.R. , Arora Rakesh C. , Ali Ayyaz , Almoustadi Waiel , Xiang Bo , Wang Fei , Large Stephen , King Scott B. , Tomanek Boguslaw , Tian Ganghong
Published: May 2011

Purpose:

To validate noninvasive cardiac output measurements of phase‐contrast magnetic resonance imaging (PC‐MRI) and cine MRI using an invasive pressure‐volume (PV) loop technique on a swine model.

Materials and Methods:

We compared three methods for evaluating cardiac function at rest and under pharmaceutical low‐dose inotropic infusion conditions: 1) phase‐contrast MRI, 2) cine MRI, and 3) PV loop relationship. These measurements were made in 14 domestic pigs under rest conditions. Identical MRI acquisitions and PV loop analysis were performed on six pigs from the same group that received an infusion of dobutamine 2.5 μg/kg/min. Cardiac outputs from all measurements were analyzed and compared using linear regression and Bland–Altman analysis.

Results:

Noninvasive PC‐MRI and cine MRI did not show any significant differences compared to an invasive PV loop technique for measurement of cardiac output under both rest (PC‐MRI, cine MRI, and PV loop, 3.17 ± 0.45, 3.18 ± 0.61, 3.45 ± 0.41 L/min, respectively) and pharmaceutical low‐dose inotropic infusion conditions (PC‐MRI, cine MRI, and PV loop, 4.78 ± 0.53, 4.7 ± 0.6, 4.96 ± 0.48 L/min, respectively). Statistical analysis showed good agreement of cardiac output measurements at rest (R2 = 0.83) and under low‐dose inotropic infusion conditions (R2 = 0.74) using PC‐MRI and PV loop techniques. Cardiac output measurement using cine MRI and PV loop techniques also showed good agreement at rest (R2 = 0.85) and under low‐dose inotropic infusion conditions (R2 = 0.76). Furthermore, cardiac outputs determined with the three modalities showed good agreement over a wide range of heart rates (90–180 bpm).

Conclusion:

MRI can provide a reliable, noninvasive measurement of cardiac output that can be carried out without the complications that are inherent with current invasive procedures. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.
Substitution and proton doping effect on SrZrO3 behaviour: high‐pressure Raman study
Authors: Slodczyk Aneta , Limage Marie‐Hélène , Colomban Philippe , Zaafrani Oumaya , Grasset Frédéric , Loricourt Johan , Sala Béatrice
Published: May 2011

The high‐pressure Raman studies of pure, Yb‐modified, protonated and non‐protonated SrZrO3 dense ceramics were performed between 0.1 and 40 GPa using a diamond anvil cell. Lanthanide‐modified, protonated SrZrO3 perovskites are potential materials for electrolytic membrane in fuel cells and electrolysers working at medium temperature. The comparison of the Raman spectra shows important differences in the pressure behaviour between the pure and Yb‐modified SrZrO3 ceramics. SrZrO3 exhibits a rigid structure without any structural modification, whereas for both SrZr0.93 Yb0.07 O2.965 and SrZr0.93 Yb0.07 O2.962 H0.003 a sequence of structural modifications at 10, 20 and 35 GPa is revealed. The character of these structural modifications is very similar to that observed as a function of the temperature (orthorhombic Pnma 750 °C → pseudo‐tetragonal Imma 840 °C → tetragonal I4/mcm 1070 °C → cubic Pm3m), which suggests that they can be considered as the phase transitions. Despite the low level of proton content (0.3% mole/mole), significant difference between protonated and non‐protonated compounds is observed for the 700–750 cm−1 doublet assigned to the ZrO octahedron stretching mode, perturbed by an oxygen atom vacancy and/or neighbouring Yb ion. The location of proton is discussed. Copyright © 2011 John Wiley & Sons, Ltd.
A highly sensitive LC‐MS/MS method capable of simultaneously quantitating celiprolol and atenolol in human plasma for a cassette cold‐microdosing study
Authors: Minamide Yoshiyuki , Osawa Yukio , Nishida Hiroshi , Igarashi Harue , Kudoh Shinobu
Published: May 2011

A highly sensitive simultaneous quantitative method for a cassette cold‐microdosing study on celiprolol and atenolol was developed with liquid chromatography–tandem mass spectrometry. The method utilizes a combination of solid‐phase extraction (SPE) with strong cation exchange (SCX) cartridge columns and reversed‐phase chromatography with an ODS analytical column. SCX‐SPE cartridge columns (100 mg sorbent) were used for a selective extraction of celiprolol, atenolol and metoprolol (internal standard) from 500 μL of human plasma samples. Turbo‐ion spray at positive mode was employed for the ionization of the drug compounds. Quantitation was performed on a triple quadrupole mass spectrometer by selected reaction monitoring with the transitions of m/z 380 to m/z 251 for celiprolol and m/z 267 to m/z 145 for atenolol. Separation of analytes was achieved on an ODS column (100 mm length×2.1 mm id, 3 μm) by a gradient elution with 10 mM formic acid and methanol by varying their proportion at a flow rate of 0.2 mL/min. The method was validated in the range of 1–250 pg/mL for celiprolol and 2.5–250 pg/mL for atenolol and was successfully applied to the elucidation of pharmacokinetic profiling in a cold cassette microdosing study of the β‐blockers.
Rapid analysis of aldehydes by simultaneous microextraction and derivatization followed by GC‐MS
Authors: Ye Qing , Zheng Dagui , Liu Linhai , Hong Liming
Published: May 2011

Ultrasound‐assisted dispersive liquid–liquid microextraction (UDLLME) and simultaneous derivatization followed by GC‐MS was developed for the analysis of four aldehydes including acetaldehyde (ACE), propionaldehyde (PRO), butyraldehyde (BUT) and valeraldehyde (VAL) in water samples. In the proposed method, the aldehydes were derivatized with O‐2,3,4,5,6‐(pentafluorobenzyl)hydroxylamine (PFBHA) and extracted by UDLLME in aqueous solution simultaneously; finally, the derivatives were analyzed by GC‐MS. The experimental parameters were investigated and the method validations were studied. The optimal conditions were: aqueous sample of 5 mL, PFBHA of 50 μL, 1.0 mL ethanol (disperser solvent) containing 20 μL chlorobenzene (extraction solvent), ultrasound time of 2 min and centrifuging time of 3 min at 6000 rpm. The proposed method provided satisfactory precision (RSD 1.8–10.2%), wide linear range (0.8–160 μg/L), good linearity (R2 0.9983–0.9993), good relative recovery (85–105%) and low limit of detection (0.16–0.23 μg/L). The proposed method was successfully applied for the analysis of aldehydes in water samples. The experimental results showed that the proposed method was a very simple, rapid, low‐cost, sensitive and efficient analytical method for the determination of trace amount of aldehydes in water samples.
A novel RP‐HPLC method for simultaneous determination of potassium sorbate and sodium benzoate in soft drinks using C18‐bonded monolithic silica column
Authors: Can Nafiz O. , Arli Goksel , Lafci Yigit
Published: May 2011

Potassium sorbate and sodium benzoate are food additives that are generally employed for prevention of food spoilage originating from bacteria, molds or yeasts. Although these compounds were generally recognized as safe due to their low risk of acute and chronic toxicity, they have limitations of usage to protect human health. Development and validation of a novel RP‐HPLC method, in which a C18‐bonded monolithic silica column was used as stationary phase to assay these compounds, is described for the first time. Aliquots of 10 μL of samples were injected into chromatograph and eluted using phosphate buffer (0.025 M, pH 2.0)–water–acetonitrile (50:45:5, v/v/v) solution, which was pumped at the rate of 3.0 mL/min. To sharpen the peaks, 10 mM octylamine was added to the mobile phase. Potassium sorbate and sodium benzoate were detected at about 12th and 14th min, respectively, and quantified at 230 nm using photodiode array detector. A total of 41 samples were prepared by simply filtering through 0.45 μm filters after sonication, and injected into the system without any pre‐treatment steps. Applicability of the method was demonstrated by performing total procedure on samples of different brands and types, and their compliance to official regulations was assessed.
Involvement of the transcription factor twist in phenotype alteration through epithelial–mesenchymal transition in lung cancer cells
Authors: Nakashima Harunori , Hashimoto Naozumi , Aoyama Daisuke , Kohnoh Takashi , Sakamoto Koji , Kusunose Masaaki , Imaizumi Kazuyoshi , Takeyama Yoshihiro , Sato Mitsuo , Kawabe Tsutomu , Hasegawa Yoshinori
Published: May 2011

Epithelial–mesenchymal transition (EMT), which involves the persistent loss of epithelial markers and expression of mesenchymal markers, is assumed to have a critical role in not only tissue development during embryogenesis but also central mechanisms that enhance the invasive and metastatic ability of cancer cells. Twist has been identified to play an essential role in EMT‐mediated tumor invasion and metastasis. Although recent studies suggest that twist expression levels in tissue specimens of lung cancer might be associated with prognosis, the expression of twist in lung cancer cells itself and its effect have not been fully evaluated. Here, we evaluated twist expression and its effect on phenotype alteration in lung cancer cell lines. Twist expression varied among human lung cancer cell lines. The lung cancer cell lines with high twist expression also tended to show a high vimentin/E‐cadherin ratio, which was supported by a migration assay, in which high twist expression gave rise to high cell motility. Furthermore, in comparison to control cells, the lung cancer cells with ectopic expression of twist showed a significant phenotype alteration through EMT and an increasing ability to migrate in vitro, in part, due to a tenfold increase in matrix metalloproteinases activity and almost a 60% increase in modulation of focal adhesion kinase activity, although a contribution of microRNA appeared unlikely in our study. Our present analysis of twist expression in lung cancer provide clues to comprehensive understanding of the mechanisms, by which metastasis often develops in lung cancer. © 2011 Wiley Periodicals, Inc.
Quality of life in patients with treated and clinically stable Wilson's disease
Authors: Svetel Marina , Pekmezović Tatjana , Tomić Aleksandra , Kresojević Nikola , Potrebić Aleksandra , Ješić Rada , Kostić Vladimir S.
Published: May 2011

Health‐related quality of life (HRQoL) in Wilson's disease (WD) has not been extensively studied. Therefore, the purpose of this cross‐sectional study was to identify clinical and demographic factors influencing HRQoL in 60 treated, clinically stable patients with WD using a generic questionnaire, the Medical Outcomes Study Short‐Form 36‐Item Health Survey (SF‐36). The level of disability and grading of WD multisystemic manifestations were assessed by the Global Assessment Scale for WD (GAS for WD). The Mini Mental State Examination (MMSE) and the 21‐item Hamilton Depression Rating Scale (HDRS) scoring were also applied by the same trained interviewers. Lower scores on the SF‐36 domains were found in patients with neurological compared with those with a predominantly hepatic form of WD. The HRQoL of patients with WD and psychiatric symptoms was also lower than that of those without them. Finally, significant inverse correlations were obtained between the various SF‐36 domains and all the following: period of latency from the first symptoms/signs appearance and treatment initiation, MMSE and HDRS scores, and different domains of the GAS for WD. © 2011 Movement Disorder Society
Phenethyl isothiocyanate sensitizes human cervical cancer cells to apoptosis induced by cisplatin
Authors: Wang Xiantao , Govind Sudha , Sajankila Shyama P. , Mi Lixin , Roy Rabindra , Chung Fung‐Lung
Published: May 2011

Scope: Naturally‐occurring chemopreventive agent phenethyl isothiocyanate (PEITC), derived primarily from watercress, has been shown to inhibit cell growth and induce apoptosis in cancer cells. In this study, we examined the potential of PEITC in enhancing cisplatin‐induced apoptosis in cervical cancer cells and its mechanisms.

Methods and results: HeLa cells were exposed to PEITC, cisplatin or both. Pretreatment of cells with PEITC strongly enhanced cisplatin‐induced cytotoxicity. PEITC activated the mitogen‐activated protein kinases, including c‐Jun N‐terminal kinase (JNK), extracellular signal‐related kinase (ERK), and p38. Caspase‐3 activity assay demonstrated that the synergistic induction of apoptosis was significantly attenuated by MEK1/2 inhibitor U0126, but not by JNK or p38 inhibitor, suggesting that ERK activation is responsible for the synergistic effect. We found that NF‐κB signaling pathway is not involved in the synergistic effect. Sulforaphane and benzyl isothiocyanate, two other members of the isothiocyanate family, also sensitize HeLa cells to apoptosis induced by cisplatin. Furthermore, we found that the synergistic effect was also observed in cervical cancer C33A and breast cancer MCF‐7 cells but not in normal mammary epithelial MCF‐10A cells. Finally, we demonstrated that Noxa induction was associated with apoptosis induced by PEITC plus cisplatin.

Conclusion: Taken together, this study shows that PEITC can sensitize cancer cells to apoptosis induced by cisplatin and this effect is mediated through ERK activation, suggesting the potential of PEITC to be used as an adjuvant with cisplatin in combination therapeutic treatments.
Vertical handover (VHO) framework for future collaborative wireless networks
Authors: Dimitriou Nikos , Sarakis Lambros , Loukatos Dimitrios , Kormentzas George , Skianis Charalambos
Published: May 2011

The paper focuses on the concept of the vertical handover (VHO) among collaborative wireless networks, which is the necessary driver for seamless mobility and thus for the ability of the user to be always best connected. The paper discusses the required enabling architecture for distributed VHO decision making that is based on the principles of the IEEE 1900.4 standard and on the key media‐independent signaling procedure related to the IEEE 802.21 standard. The proposed framework combines the ‘lower‐layer’ and ‘higher layer’ intelligence in a unified and media‐independent way, to drive handover decisions based on rich terminal and network context information. The paper provides a detailed description of the VHO framework and of the key interactions between its key functional blocks. Additionally, the paper includes a series of validation results corresponding to an implementation of the presented framework. Furthermore, the paper includes a discussion comparing the capabilities offered by the proposed framework with those proposed by other similar proposals, which shows the potential benefits and tradeoffs of the introduced concepts. Copyright © 2011 John Wiley & Sons, Ltd.
NASCA‐HMBC, a New NMR Methodology for the Resolution of Severely Overlapping Signals: Application to the Study of Agathisflavone
Authors: Bayiha Ba Njock Gaétan , Bartholomeusz Trixie Ann , Foroozandeh Mohammadali , Pegnyemb Dieudonné Emmanuel , Christen Philippe , Jeannerat Damien
Published: May 2011

Introduction

Standard NMR 2D heteronuclear HMBC spectra have a low resolution in the indirect carbon dimension, making it very difficult to assign signals to individual carbons when their chemical shifts are < 0.3 ppm apart.

Objective

To establish spectral aliasing for HMBC experiments to improve the resolution in the carbon dimension without increasing the total experimental time and avoiding ambiguities in the observed chemical shifts.

Methodology

The NASCA‐HMBC (Non‐ambiguous Assignment by Superposition of Coupled Aliased HMBC) methodology combines a pair of HMBC spectra recorded with slightly different carbon windows to provide typically one order of magnitude increase in the resolution and unambiguous chemical shifts.

Results

The application of this methodology to a biflavonoid found in Ouratea gilgiana resulted in spectra with a sufficiently high resolution to make the assignment straightforward and report, for the first time, the full assignment of agathisflavone.

Conclusion

The methodology should find many applications in dimeric and oligomeric compounds such as peptides, carbohydrates, polyketides and other cases where signal clustering is expected. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis, structure and properties of polyimide–silica hybrid composites based on biphenyltetracarboxylic dianhydride
Authors: Jena Kishore K , Raju Kothapalli VSN , Rout Tapan K
Published: May 2011

A simple and efficient way of synthesizing nanocomposite films using a dispersion technique is reported, with the resulting films having improved mechanical and thermal properties. Nano‐SiO2 was used in a biphenyltetracarboxylic dianhydride‐based poly(amic acid) precursor and found to be dispersed up to 7 wt% without any additives. The composites were cast to make 10 µm solid films to establish structure and property relationships between liquid and solid film. The structures of the liquid composite materials were studied using NMR and Fourier transform infrared spectroscopy. Solid film properties such as tensile strength, contact angles and thermal behaviour were evaluated for comparison. The properties of the composite films were found to be enhanced compared to polyimide film itself. Atomic force microscopy and macroscale mechanical measurements showed that composite films with more dipolar bonding interactions have higher elastic moduli and are more deformable. They yield higher adhesion energies, and therefore composite coatings offer greater adhesion. There was a limitation in the film formation beyond 5 wt% of silica. Copyright © 2011 Society of Chemical Industry
Synthesis of pyrene‐capped polystyrene for dispersion of pristine single‐walled carbon nanotubes
Authors: Yan Yehai , Yang Shaobei , Cui Jian , Jakisch Lothar , Pötschke Petra , Voit Brigitte
Published: May 2011

Pyrene‐capped polystyrene (PyPS) with various molecular weights (M̄n) was synthesized through the anionic polymerization method and characterized using UV, Fourier transform infrared and NMR spectroscopy and gel permeation chromatography. The polymers were then used for non‐covalent functionalization of pristine single‐walled carbon nanotubes (SWNTs). The functionalization efficiency was assessed by measuring the SWNT dispersibility in chloroform. In the presence of PyPS, the dispersibility can be as high as 372.5 mg L−1, and the dispersions containing more than 1.25 mg mL−1 of PyPS are very stable with no solid deposits observed after being centrifuged at 5000 rpm for 15 min. Once the PyPS concentration is converted to the molar concentration of the pyrene unit and the dispersibility redefined as nanotube content per molar pyrene unit, the renewed dispersibility is found to be independent of M̄n of PyPS within the detected M̄n range. For a certain PyPS polymer, however, both nanotube dispersibility and dispersion stability are strongly dependent on the PyPS concentration. These results suggest that PyPS may be used as an excellent dispersant for subsequent preparation of polystyrene/SWNT composites. Copyright © 2011 Society of Chemical Industry
The “Management-Per-Result” Approach to International Development Project Design
Authors: Ika Lavagnon A. , Lytvynov Vasyl
Published: May 2011

Results-based management (RBM) has proved to be a valuable tool for international development project management; however, there are some inconsistencies that limit the use of RBM at the design phase to manage for results. This article presents a “management-per-result” approach to reinforcing the project design function of RBM and illustrates its application to a real-life project. Shying away from a technocratic approach, it emphasizes a “quick-and-dirty” approach and proposes an updated version of the logical framework to include success criteria and factors and very rough estimates for both project costs and benefits for targeted project results for different types of projects (infrastructure development, “process” type of project, and so forth).
The key Cl− ligand for metal‐to‐ligand charge transfer in mononuclear terpyridine ruthenium(II) and binuclear ruthenium(II) tetrapyridylpyrazine complexes
Authors: Yoshikawa N. , Yamabe S. , Kanehisa N. , Inoue T. , Takashima H. , Tsukahara K.
Published: May 2011

Electronic structures of binuclear ruthenium complexes [Ru2(terpy)2(tppz)]4+ (1A) and [Ru2Cl2(L)2(tppz)]2+ {L = bpy (2A), phen (3A), and dpphen (4A)} were studied by density functional theory calculations. Abbreviations of the ligands (Ls) are bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline, dpphen = 4,7‐diphenyl‐1,10‐phenanthroline, terpy = 2,2′:6′,2″‐terpyridine, and tppz = tetrakis(2‐pyridyl)pyrazine. Their mononuclear reference complexes [Ru(terpy)2]2+ (1B) and [RuClL(terpy)]+ {L = bpy (2B), phen (3B), and dpphen (4B)} were also examined. Geometries of these mononuclear and binuclear Ru(II) complexes were fully optimized. Their geometric parameters are in good agreement with the experimental data. The binuclear complexes were characterized by electrospray ionization mass spectrometry, UV–Vis spectroscopy, and cyclic voltammograms. Hexafluorophosphate salts of binuclear ruthenium complexes of 3A and 4A were newly prepared. The crystal structure of binuclear complex 1A(PF6)4 was also determined.

Orbital interactions were analyzed to characterize the metal‐to‐ligand charge‐transfer (MLCT) states in these complexes. The Cl− ligand works to raise the orbital energy of the metal lone pair, which leads to the low MLCT state. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of monomer water solubility on cationic microemulsion polymerization of three components (water, surfactant, and monomer)
Authors: Arellano Jesús , Flores Jorge , Zuluaga Fabio , Mendizábal Eduardo , Katime Issa
Published: May 2011

Here, we present the oil/water (O/W) microemulsion polymerization in three‐component microemulsions of n‐butyl acrylate, ethyl acrylate, and methyl acrylate, monomers with similar chemical structures but different water solubilities using the cationic surfactant dodecyl trimethyl ammonium bromide. The effects of monomer water solubility, initiator type and initial monomer concentration on the polymerization kinetics were studied. Reaction rates were high with final conversions between 70 and 98% depending on the monomer and reaction conditions. The final latexes were bluish, with a particle size ranging between 20 and 50 nm and polymer with molar masses in the order of 106 g mol−1. Increasing monomer water solubility resulted in a slower reaction rate, larger particles and a lower number density of particles. A higher reaction rate, larger average particle size and higher particle number density were obtained by increasing the monomer concentration. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis, characterization, and rheological properties of multiarm stars with poly(glycidol) core and poly(methyl methacrylate) arms by AGET ATRP
Authors: Morell Mireia , Voit Brigitte , Ramis Xavier , Serra Àngels , Lederer Albena
Published: May 2011

Well‐defined multiarm star block copolymers poly(glycidol)‐b‐poly(methyl methacrylate) (PGOHBr‐b‐PMMAx) with an average number of PMMA arms of 85, 55, and 45 have been prepared. The core‐first approach has been selected as the methodology using atom transfer radical polymerization (ATRP) of MMA from an activated hyperbranched poly(glycidol) as the core. These activated hyperbranched macroinitiators were prepared by esterification of hyperbranched poly(glycidol) (PGOH) with 2‐bromoisobutyryl bromide. The effect of monomer/initiator ratio, catalyst concentration, time, temperature, and solvent on the growing of the arms has been studied in detail in order to optimize the process and to diminish the radical‐radical coupling. The final products and intermediates were characterized by means of size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) and Fourier transform‐infrared (FTIR) spectroscopy. The length of PMMA arms was determined by SEC after cleavage of ester bond linked to PGOH core. Glass transition temperature (Tg), thermal stability and rheological properties of the multiarm star copolymers were also studied. Finally, tapping mode atomic force microscopy (TMAFM) allowed the clear visualization of nano‐sized particles (80–200 nm) corresponding to individual star molecules. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of pyrene end‐capped A6 dendrimer and star polymer with phosphazene core via “click chemistry”
Authors: Gorur Mesut , Yilmaz Faruk , Kilic Adem , Sahin Zeynep M. , Demirci Ali
Published: May 2011

Novel hexa‐armed and pyrene (Pyr) end‐capped phosphazene dendrimer [N3P3‐(Pyr)6] and star polymer with poly(ε‐caprolactone) (PCL) arms [N3P3‐(PCL‐Pyr)6] were prepared via two series of reactions. In these series, core‐first approach was used starting from a hexa‐hydroxy functional phosphazene derivative (N3P3‐(OH)6). It was used as an initiator in the ring‐opening polymerization of ε‐caprolactone to prepare a hexa‐armed PCL star polymer (N3P3‐(PCL‐OH)6). Hydroxyl functionalities of N3P3‐(OH)6 and N3P3‐(PCL‐OH)6 were then successfully converted into bromide and azide, in turn. Further end‐group modifications of azide functional dendrimer precursor (N3P3‐(N3)6) and star polymer (N3P3‐(PCL‐N3)6) were achieved quantitatively via the Cu(I) catalyzed click reaction between azide functional groups and 1‐ethynyl pyrene in the final step. Moreover, the pyrene end‐capped phosphazene dendrimer and star polymer were used in noncovalent functionalization of multiwalled carbon nanotubes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Influence of dc Pulsed Atmospheric Pressure Plasma Jet Processing Conditions on Polymer Activation
Authors: Dowling Denis P. , O'Neill Feidhlim T. , Langlais Simon J. , Law Victor J.
Published: May 2011

Plasma treatments are widely used to activate polymer surfaces prior to adhesive bonding. This study investigates the influence of plasma treatment conditions on the surface activation of a range of polymers using the PlasmaTreat (Open Air) system. In this study the effect of dc pulse plasma cycle time, compressed air flow rate and the plasma jet nozzle to substrate distance on the plasma discharge was examined. The influence that the dc pulse plasma cycle time parameter has on the activation of polypropylene, polystyrene and polycarbonate was also investigated. The level of polymer surface activation was evaluated based on the change in water contact angle after plasma treatment. The polymer surface properties were also monitored using AFM and XPS measurements. The heating effect of the plasma was monitored using both infrared thermographic camera and thermocouple measurements. Plasma diagnostics measurements were obtained using the photo‐diode and optical emission spectroscopy techniques. From this study it was concluded that for the PlasmaTreat system the level of plasma activation was closely correlated with the dc pulsed plasma cycle time, which is a measure of the plasma intensity. For example, the more intense plasma obtained with shorter cycle times gave higher levels of polymer activation. The optimized pulsed plasma cycle times were found to be specific for a given polymer type and related to their thermal properties. The pulsed cycle times were also found to correlate with both the substrate and plasma gas temperatures.

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The role of Pax2 in mouse prostate development
Authors: Xu Ben , Hariharan Arun , Rakshit Sabita , Dressler Gregory R. , Wellik Deneen M.
Published: May 2011

BACKGROUND

Loss‐of‐function of Pax2 results in severe defects of the male reproductive system, and Pax2 expression is detected in mouse prostate lobes and human prostatic cancers. However, the role for Pax2 in prostate development remains poorly understood.

METHODS

The expression of Pax2 was examined by in situ hybridization at various developmental stages. Urogenital sinuses were dissected out at E18.5 from mouse Pax2 mutants and controls, cultured in vitro or grafted under the renal capsule of CD1 nude mice. The expression of prostate developmental regulatory factors was analyzed by semi‐quantitative real‐time PCR or immuohistochemistry.

RESULTS

Pax2 is expressed in the epithelial cells of prostate buds. Loss‐of‐function of Pax2 does not affect the initiation of prostatic buds, but in vitro culture assays show that the prostates of Pax2 mutants are hypomorphic and branching is severely disrupted compared to controls. RT‐PCR data from Pax2 mutant prostates demonstrate increased expression levels of dorsolateral prostate marker MSMB and ventral prostate marker SBP and dramatically reduced expression levels of anterior prostate marker TGM4.

CONCLUSIONS

Pax2 is essential for mouse prostate development and regulates prostatic ductal growth, branching, and lobe‐specific identity. These findings are important for understanding the molecular regulatory mechanisms in prostate development. Prostate 72:217–224, 2012. © 2011 Wiley Periodicals, Inc.
Assessment of resistance risk in Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) to chlorantraniliprole
Authors: Lai Tiancai , Su Jianya
Published: May 2011

BACKGROUND: Beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), is a major pest of numerous cultivated crops. Chlorantraniliprole, the first commercialised ryanodine receptor insecticide from the anthranilic diamide class, has exceptional insecticidal activity on a range of lepidopteran pests. The aim of this study was to assess the resistance of S. exigua to chlorantraniliprole in the laboratory.

RESULTS: A field‐collected population of S. exigua was selected after repeated exposure to chlorantraniliprole to determine the risk of resistance evolution. After 22 generations of selection, there was a 12.0‐fold increase in LC50. The realised heritability (h2) of resistance was estimated as 0.1082 by using threshold trait analysis. The projected rate of resistance evolution indicated that, if h2 = 0.1082 and 70% of the population was killed at each generation, then a tenfold increase in LC50 would be expected in 21.7 generations for chlorantraniliprole.

CONCLUSION: These results show that the risk of resistance development to chlorantraniliprole exists in S. exigua after continuous application. Copyright © 2011 Society of Chemical Industry
Psychoses: an evidence‐based approach to drug treatment
Authors: Livingston Martin
Published: May 2011

Of the wide range of drugs available to treat psychoses, atypicals are often preferred as they may be better tolerated. Our Drug review discusses the properties and uses of current drug treatments, followed by sources of further information and a review of prescription data. Copyright © 2011 Wiley Interface Ltd
The use of combined medications in the treatment of type 2 diabetes
Authors: Bailey Cliff , Wallymahmed Maureen , Brice Richard
Published: May 2011

Diabetes is a complex disease and patients often require multiple therapies to control the condition. For some patients, the prospect of taking several different drugs can be daunting, especially if they are already taking medications for other conditions. This Expert Panel Discussion considers which patients could benefit from taking drugs in a combined formulation, at what stage combined formulations should be used and what combined formulations are available. Copyright © 2011 Wiley Interface Ltd
Diagnosis and management of suspected drug allergies
Authors: Farooque Sophie
Published: May 2011

Allergic reactions can be caused by commonly prescribed drugs and can lead to fatal anaphylaxis. Here, the author describes the typical reactions to the drugs implicated and how and when to investigate a suspected drug allergy. Copyright © 2011 Wiley Interface Ltd
Alternatives to Pulmicort MDIs
Authors: Chaplin Steve
Published: May 2011

Scrip points highlights the problems that can arise when writing prescriptions and advises how queries from the pharmacy can be reduced and potentially dangerous errors avoided. Copyright © 2011 Wiley Interface Ltd
The current status of ultraviolet laser diodes
Authors: Yoshida Harumasa , Kuwabara Masakazu , Yamashita Yoji , Uchiyama Kazuya , Kan Hirofumi
Published: May 2011

We report on nitride laser diode lasing at short ultraviolet wavelengths. We first present room temperature operations of GaN/AlGaN multiple‐quantum‐well (MQW) laser diodes under pulsed current mode. Then we report on the results of thorough investigation of the device characteristics. The optical and temperature characteristics as well as the carrier recombination of the devices have been investigated. We lastly present the first demonstration of indium‐free nitride laser diode. The laser operation of the AlGaN MQW laser diodes open the door to laser operation at shorter ultraviolet wavelengths.
GaGdN/AlGaN multiple quantum disks grown by RF‐plasma‐assisted molecular‐beam epitaxy
Authors: Tambo H. , Hasegawa S. , Uenaka M. , Zhou Y. K. , Emura S. , Asahi H.
Published: May 2011

III–V‐based diluted magnetic semiconductor (DMS) GaGdN/AlGaN multiple quantum disks (MQDisks) were fabricated on Si (001) substrates with native silicon oxides by RF‐plasma‐assisted molecular‐beam epitaxy (RF‐MBE). It was found that the degree of the c‐axis orientation of GaGdN/AlGaN MQDisks and the Ga atomic configuration around Gd atom were improved due to the growth of AlGaN disks, comparing with the GaGdN nanorods grown without AlGaN disks. Additionally, GaGdN/AlGaN MQDisks showed larger saturation magnetisation than that of the GaGdN nanorods. With increasing the height of AlGaN disk, saturation magnetisation was increased.
Dielectric function of Al‐rich AlInN in the range 1–18 eV
Authors: Sakalauskas E. , Behmenburg H. , Schley P. , Gobsch G. , Giesen C. , Kalisch H. , Jansen R. H. , Heuken M. , Goldhahn R.
Published: May 2011

The ordinary dielectric function (DF) is presented for high quality Al‐rich Al1−xInxN alloy films pseudomorphically grown on GaN in the photon energy range 1–18 eV determined by spectroscopic ellipsometry at room temperature (synchrotron radiation – BESSY II). The (0001)‐oriented layers with In content of 14.3 and 15.4% were grown by metal‐organic vapour phase epitaxy on thick GaN buffers with sapphire substrates. The sharp onset of the imaginary part of the DF defines the direct absorption edge. In previous studies the DF of Al‐rich AlInN were investigated in the photon energy range 1–10 eV, and three high‐energy critical points (CPs) of the band structure (Van Hove singularities) were observed. The current study was performed in the extended photon energy range 10–18 eV and three CPs of the band structure at ∼10.6, ∼12.5 and ∼14.2 eV were detected. XRD measurements revealed the pseudomorphic growth of AlInN films and yielded the composition. Finally, the band gap value of 4.68 eV and high‐frequency dielectric constant value of 4.55 were evaluated for sample with 15.4% In content.
Growth of high‐quality InSb layer on (001) Si substrate with an initial intermediate‐layer of InAs quantum dots
Authors: Lim J. Y. , Song J. D. , Choi W. J. , Ahn J. P. , Yang H. S.
Published: May 2011

In this study, we have attempted a growth of InSb film on the cost‐effective, (001)‐Si substrate inserting a thin intermediate‐layer of InAs quantum dots (QDs) at the InSb/Si interface. Analysis of the interface region using transmission electron microscopy reveals that, during the subsequent InSb‐growth process, InAs QDs have disappeared leaving instead a thin interlayer of InAs. The resulting 2.8‐µm‐thick InSb film on (001) Si is found to have an electron mobility of 40 907 cm2/Vs at 300 K, which turned out to be the highest value for InSb with comparable thickness grown on Si substrate.
Optical and structural properties of silicon‐rich silicon oxide films: Comparison of ion implantation and molecular beam deposition methods
Authors: Nikitin Timur , Aitola Kerttu , Novikov Sergei , Räsänen Markku , Velagapudi Rama , Sainio Jani , Lahtinen Jouko , Mizohata Kenichiro , Ahlgren Tommy , Khriachtchev Leonid
Published: May 2011

We compare optical and structural properties of silicon‐rich silicon oxide (SiOx, x ∼ 1.8) films obtained by ion implantation and molecular beam deposition (MBD). Before annealing, amorphous clusters (≥2 nm) are present in the MBD samples whereas these are absent for ion implantation, and the absorption at 488 nm is much stronger for MBD. Upon annealing, the absorption coefficient increases for the implanted material but the opposite change occurs for MBD. For both preparation methods, annealing at ∼1100 °C produces silicon nanocrystals (Si‐nc) and enhances the 1.5‐eV photoluminescence (PL) whereas annealing at 1200 °C decreases the PL, especially for the implanted sample. The Si–SiO2 phase separation is not complete even after annealing at 1200 °C.
Magnetization reversal in Co‐base nanowire arrays
Authors: Vázquez Manuel , Vivas Laura G.
Published: May 2011

The magnetic behaviour of ordered arrays of magnetic nanowires is controlled by the combined action of anisotropy energy terms determined by geometrical shape, crystalline structure and magnetostriction, as well as by the magnetostatic interactions among them. A number of works have been reported on the role of magnetostatic interaction in arrays of nanowires, sometimes focusing on nanowires with vanishing crystalline and magnetostrictive energy terms. Here, in turn we are interested in Co‐base nanowires whose magnetocrystalline anisotropy plays a very important role. Arrays of Co‐base nanowires offer novel, sometimes unexpected behaviour that is not fully understood. Such results are connected to their magnetocrystalline anisotropy, and to their complex magnetization reversal mode. Arrays of Co and Co‐base nanowires have been fabricated by template‐assisted method, by electroplating into highly ordered self‐assembled pores of nanoporous alumina membranes. Their hcp or fcc crystal structure is confirmed to depend on length of nanowires as well as on the presence of selected elements in the composition. The magnetic behaviour of these arrays has been experimentally investigated as a function of (i) geometry (e.g. diameter and, particularly short length) and (ii) composition (e.g. adding Ni or Pd). A complementary study on its temperature dependence reveals the nature of the dominant anisotropy, while the angular dependence of hysteresis loops (e.g. coercivity and remanence) enables a deeper analysis of the magnetization reversal process. Micromagnetic reversal modes are reviewed and modelling and simulations procedures introduced. Complex rotational mechanisms are concluded to be responsible for the reversal process following micromagnetic modes distinct from those pure classically established.

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SEM image of an array of Co‐base nanowires.
Study of edge termination structures for high power GaN Schottky diodes
Authors: Sundaramoorthy Vinoth Kumar , Nistor Iulian
Published: May 2011

Different structures of field plate termination were analysed by numerical simulation to enhance the breakdown voltage of quasi‐vertical GaN Schottky diodes. A bevel shaped field plate achieved a maximum breakdown voltage of 1990 V for 1.5 µm thick oxide layer with 18 µm bevel width. Maximum breakdown voltage was achieved when the bevel angle is 5°. A fabrication friendly 4 step field plate structure achieved a breakdown voltage of 1650 V and 1970 V respectively, with oxide and silicon nitride passivation. The width and thickness of the first step were the most influential factors in deciding the maximum breakdown voltage. A multi‐step field plate structure, which is an emulation of bevel structure, achieved a breakdown voltage of 1600 V and 1850 V with oxide and silicon nitride passivation layers, respectively. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical simulations of radiative recombination time in polar InGaN quantum wells
Authors: Gladysiewicz M. , Kudrawiec R. , Syperek M. , Misiewicz J. , Siekacz M. , Cywinski G. , Skierbiszewski C. , Suski T.
Published: May 2011

The radiative recombination time (τr) was calculated for inhomogeneous polar InGaN QWs emitting in the green spectral range. These calculations were performed in the framework of a model where the τr is inversely proportional to the electron‐hole overlap integral. In order to simulate inhomogeneities in this model, it was assumed that the QW width, barrier widths and indium concentration vary with a Gaussian distribution where the nominal QW width, barrier widths and indium concentration correspond to the mean value in this distribution and their fluctuations correspond to the deviation from the main value. The τr was calculated for five thousands of randomly generated InGaN QWs and next the spectral map of PL decay was generated for the calculated τr which correspond to various QW regions. The obtained maps were compared with the measured maps of PL decay for InGaN QWs emitting in the green spectral range. It has been clearly shown that QW inhomogenities (i.e., QW width fluctuations and indium concentration fluctuations) lead to a spectral dispersion of the τr and the non‐exponential behavior of PL decay curves. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of recessed ohmic contacts for AlGaN/AlN/GaN heterostructures using C(V) characterization of MSHM structures
Authors: Fagerlind Martin , Rorsman Niklas
Published: May 2011

Recess etching is used to reduce the resistance of ohmic contacts to an AlGaN/AlN/GaN heterostructure. The minimization of the resistance relies on exact etching of the barrier. For this purpose C(V) measurements of the etched contacts, before annealing, are used to characterize the effect of the recess etch. Using the C(V) measurements a Cl2/Ar based ICP/RIE etch recipe with a stabilized etch rate of approximately 3 Å/s is developed. By utilizing the recess etch the contact resistivity is reduced from the non etched 0.9 Ω · mm to 0.3 Ω · mm when approximately 2 nm remains of the barriers, while maintaining a low sheet resistance. The C(V) measurements make it possible to monitor sheet carrier density vs. etch depth. Furthermore, the C(V) measurement gives large‐area average values that is not easily obtained with AFM measurements (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Erbium doped silica‐hafnia glass ceramic waveguides
Authors: Berneschi Simone , Chiappini Andrea , Ferrari Maurizio , Pelli Stefano , Righini Giancarlo C.
Published: May 2011

Aim of this paper is to present a short review of the main results obtained in our laboratories on Er3+‐doped SiO2: HfO2 glass ceramic waveguides fabricated by sol–gel route and dip–coating technique, employing either top–down or bottom–up approach (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light induced 2D chiral structure on the surface of azo‐polymer films
Authors: Kandjani Sohrab Ahmadi , Barille Regis , Nunzi Jean‐Michel , Kheradmand Reza , Tajalli H.
Published: May 2011

In this experimental work, we present a simple method for fabrication of 2D chiral structure on the surface of an azo‐polymer film. It has been shown that illuminating of an azo‐polymer film with a single uniform laser beam can create the surface relief pattern on the surface of the film. For different state of polarization different structures are obtained. Under ∼33° incidence angle and for 45° polarization direction, the formed structure is asymmetric, and it does not have a symmetry axis in the 2D plane. The AFM images of these patterns are not superimposable with their mirror images if we rotate the images in their planes. On the other hand, the mirror images of Fourier Transform of AFM images also are not coinciding with Fourier Transform of AFM images. Consequently, this structure is a 2D chiral structure. These patterns are shown the capability to rotate the polarization state of diffracted light in the transmission regime. The changes in the polarization state of light associate with the chirality of sample. This is a one‐step very simple and reversible method to fabricate 2D chiral systems (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of structural factors related to spectroscopic data and redox potentials of CuT1 models through DFT tools
Authors: Vázquez‐Lima Hugo , Guadarrama Patricia
Published: May 2011

Six complexes, mimics of T1 Cu active site, were studied under the density functional theory framework and their redox potentials were theoretically estimated with an average error of 0.095 V. Among different functionals, the hybrid functional PBE0 gave the best results to reproduce geometric parameters and to estimate redox potentials. The use of computational methods allowed the identification of relevant structural factors to rationalize spectroscopic and redox potential measurements. The inclusion of explicit molecules of solvent (tetrahydrofurane) showed that only those complexes with net positive charge exhibit coordination with the solvent. The consideration of such interaction permits the correct estimation of redox potentials. When the equilibrium between possible coordination isomers of T1 Cu models is taken into account, a reinterpretation of spectroscopic data (EPR and UV‐vis) is possible. These equilibria are governed mainly by entropic contributions and the solvation energy. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Privacy protection for vehicular ad hoc networks by using an efficient revocable message authentication scheme
Authors: Fan Chun‐I , Hsu Ruei‐Hau , Chen Wei‐Kuei
Published: May 2011

Correctness of exchanged information and guaranteeing the privacy of vehicle owners are the two most significant security concerns for VANETs. Pseudonymous public key infrastructure (PPKI) is a practical solution to these two issues. Almost all PPKI technologies are comprehensive schemes, such as the group signature‐based and identity‐based cryptosystems. An applicable PPKI scheme for secure vehicular communication (VC) should support revocability because it is a significant functionality in VANETs to revoke certificates of vehicles for surrendering or transferring the registrations. However, the computation or space complexity in most of the revocable PPKI‐based protocols is linear when the number of vehicles or revoked vehicles increases over time. This drawback markedly degrades the efficiency and stability of secure VC. This work therefore reduces the computation complexities of authentication message verification, certificate tracing, membership revocation, and space complexity of system parameters (e.g., revocation information and public keys), such that they are independent of the number of vehicles or revoked vehicles using a novel and efficient PPKI mechanism based on bilinear mapping. The proposed scheme uses the concept of accumulator schemes and transfers the computation of accumulators from vehicles to certificate authority (CA) for achieving constant computation and storage complexities on vehicles. The computation of accumulators on CA is also low in the proposed scheme. Finally, we formally prove that the proposed scheme, which is based on q‐strong Diffie–Hellman, n‐Diffie–Hellman exponent (DHE), variant n‐DHE, and decision linear Diffie–Hellman assumptions, is secure under the definitions of traceability and anonymity. Copyright © 2011 John Wiley & Sons, Ltd.