bluuebunny/crossref_metadata_2025 huggingface dataset:
Wide tuning range cmos millimeter‐wave vco using resistors‐added mosfet varactor
Authors: Chang Ho‐Jun , Kim Sung‐Jun , Lim Chang‐Woo , Yun Tae‐Yeoul
Published: May 2012

This article presents a CMOS millimeter‐wave voltage‐controlled oscillator (VCO), which provides a wide tuning range using a resistors‐added MOSFET varactor.Large resistors connected to the source and bulk allow a MOSFET varactor to lower minimum capacitance and to maintain maximum capacitance compared to a conventional MOSFET varactor. Thus, the total capacitance tuning range of the proposed varactor is expanded to ±46.1%, allowing a VCO with the new varactor to possess a frequency tuning range of 13.4% from 29.3 to 33.5 GHz. The measured phase noise is −97.8 dBc/Hz at a 1‐MHz offset at the center frequency of 31.3 GHz. The VCO in a 0.18‐μm standard CMOS process dissipates 12.6 mW from a 1.8‐V supply voltage. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1777–1783, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26983
Resonance assignments of diastereotopic CH2 protons in the anomeric side chain of selenoglycosides by means of 2J(Se,H) spin‐spin coupling constants
Authors: Rusakov Yury Yu. , Krivdin Leonid B. , Kumar Ambati Ashok , Szilágyi László , Kövér Katalin E.
Published: May 2012

Unambiguous resonance assignments of diastereotopic CH2 protons in the anomeric side chain of nine alkyl‐ and aralkylselenoglycosides have been carried out on the basis of experimental CPMG‐HSQMBC measurements and theoretical second order polarization propagator approach (SOPPA) calculations of geminal 77Se‐1H spin‐spin coupling constants involving diastereotopic pro‐R and pro‐S protons. Theoretical conformational analyses have been performed at the MP2/6‐311G** level. The conformational space of each of the selenoglycosides under study could be adequately described as a mixture of six interconverting conformers with the molar fractions depending on the nature of the side chain substituent at the selenium atom. The good agreement observed between measured and the weighted conformational averaged values of the calculated coupling constants provides a basis for reliable diastereotopic assignments in this type of carbohydrate structures. Copyright © 2012 John Wiley & Sons, Ltd.
An augmented Lagrangian algorithm for contact mechanics based on linear regression
Authors: Zavarise G. , De Lorenzis L.
Published: May 2012

The penalty method for the solution of contact problems yields an approximate satisfaction of the contact constraints. Augmentation schemes, which can be adopted to improve the solution, either include the contact forces as additional unknowns or are strongly affected by the penalty parameter and display a poor convergence rate. In a previous investigation, an unconventional augmentation scheme was proposed, on the basis of estimating the ‘exact’ values of the contact forces through linear interpolation of a database extracted by the previous converged states. An enhanced version of this method is proposed herein. With respect to the original method, the enhanced one eliminates some numerical problems and improves the regularity of the convergence path by carrying out the estimate through linear regression methods. The resulting convergence rate is superlinear, and the method is quite insensitive to the penalty parameter. The main underlying concept is that, within the iterative solution of a non‐linear problem, linear regression techniques may be used as a tool to ‘shoot’ faster to the final solution, on the basis of a set of intermediate data. The generality of this concept makes it potentially applicable to contact problems in more general settings, as well as to other categories of non‐linear problems. Copyright © 2012 John Wiley & Sons, Ltd.
Preparation and properties of fluorine‐containing polysiloxanes obtained via ring‐opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane catalyzed by rare earth solid superacid SO$_{4}^{2-}$/TiO2/Ln3+
Authors: Yang Xiongfa , Shao Qian , Yang Linlin , Cao Cheng , Hua Xilin , Wu Lianbin , Lai Guoqiao
Published: May 2012

Traditional catalysts such as (CH3)4NOH, NaOH, KOH, n‐BuLi and CF3SO3H can catalyze the copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane to afford fluorine‐containing polysiloxanes. However, use of these catalysts poses significant difficulties in handling and separation. In this work, fluorine‐containing polysiloxanes were synthesized through a novel and environmentally friendly method: ring‐opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane catalyzed by rare earth solid superacid SO$_{4}^{2-}$/TiO2/Ln3+. The effects of reaction conditions were examined in detail. The yield sequence of various rare earth catalysts is Nd ∼ La ∼ Y ∼ Sm > Gd, while the number‐average molecular weight sequence is Nd > La > Y > Sm > Gd. The optimum conditions for the ring‐opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane are as follows: [Nd3+] = 0.05 mol L−1 and $[\hbox{SO}_{4}^{2-}] = 1.85$ mol L−1 in the immersing solution, SO$_{4}^{2-}$/TiO2/Nd3+ calcined at 500 °C and the copolymerization conducted at 80 °C for 40 min. Structures of resulting copolymers were characterized using size exclusion chromatography, 1H NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis and contact angle measurements. According to the copolymerization features, a cationic equilibrium reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry
Commercial biodegradable material for food contact: methodology for assessment of service life
Authors: Dopico‐García María Sonia , Ares‐Pernas Ana , González‐Rodríguez María Victoria , López‐Vilariño José Manuel , Abad‐López María José
Published: May 2012

Control of the durability of commercial biodegradable materials when used as food packaging is relevant to guarantee the safety of food. The service life performance of a commercial material based on poly(lactic acid) was assessed through an aging test which mimics its real use (immersion in water at 40 °C for up to 6.5 months). The ability of different techniques for the evaluation of polymer decomposition was investigated and two types of degradation were shown, a reversible physical aging and a permanent deterioration due to hydrolysis. Physical aging was reflected in differential scanning calorimetry scans by increased glass transition temperature and corresponding enthalpy. A gradual decrease of crystallization temperature and increase of melting temperature and crystallinity were also observed. The progressive loss of mechanical properties reflected the sum of both types of degradation. Hardness, flexural modulus and flexural strength were more sensitive to deterioration than strain. The highest toughness of the material was achieved at two months. The cleavage of polymer chains and release of substances caused increased migration levels, especially marked for long time periods. Water uptake and migration levels followed a concordant pattern and experienced the highest increases. A simple protocol for quality control based on the obtained results is suggested. Copyright © 2012 Society of Chemical Industry
Proteomic analysis of the microenvironment of developing oocytes
Authors: Twigt John , Steegers‐Theunissen Regine P. , Bezstarosti Karel , Demmers Jeroen A. A.
Published: May 2012

We utilized a setup based on extensive pre‐fractionation of proteolytic peptides and nanoflow reversed‐phase LC‐MS/MS to identify the (sub)proteome of human follicular fluid (FF). In this in‐depth screen, 246 specific proteins were identified, the majority of which are involved in coagulation‐ and immune‐response pathways. Our aim is to define a set of FF protein markers, which could predict oocyte quality.
Protein alteration of HepG2.2.15 cells induced by iron overload
Authors: Fang Caiyun , Zhao Chao , Liu Xiaohui , Yang Pengyuan , Lu Haojie
Published: May 2012

Hepatitis B can progress into hepatocellular carcinoma. Body irons may interfere with the clearance of hepatitis B virus (HBV) and contribute to genesis of tumor. To investigate the role of iron played in HBV‐related pathogenesis, here we studied the effect of iron with different concentrations and valence states on growth of HepG2.2.15 cells and secretion of virus proteins. A strong tolerance of HepG2.2.15 cells to iron challenge was found. The concentration of hepatitis B surface antigen in cell culture medium was decreased after iron stimulation. Lower concentrations of iron facilitated hepatitis B e‐antigen (HBeAg) secretion. Fe2+ appeared more effective on HBeAg secretion than Fe3+ did. In parallel, the differential protein profiles in HepG2.2.15 cells were studied by iTRAQ and LC‐MS/MS. The differentially expressed proteins were mainly involved in stress response, signal transduction, apoptosis, etc. Four proteins (14‐3‐3 β/α, VCP, migration inhibitory factor, and Nup153) were verified by Western‐blotting and found to be consistent with the iTRAQ data. Interestingly, nuclear import of Nuclear factor kappa B (NFκB) and its activity were found to be affected by the decreased Nup153 in iron stimulated HepG2.2.15 cells. The results may indicate possible molecular mechanism how the synergism of HBV and iron stimulation damages host liver cells.
PRDB: Protein Repeat DataBase
Authors: Jorda Julien , Baudrand Thierry , Kajava Andrey V.
Published: May 2012

Rapidly increasing genomic data present new challenges for scientists: making sense of millions of amino acid sequences requires a systematic approach and information about their 3D structure, function, and evolution. Over the last decade, numerous studies demonstrated the fundamental importance of protein tandem repeats and their involvement in human diseases. Bioinformatics analysis of these regions requires special computer programs and databases, since the conventional approaches predominantly developed for globular domains have limited success. To perform a global comparative analysis of protein tandem repeats, we developed the Protein Tandem Repeat DataBase (PRDB). PRDB is a curated database that includes the protein tandem repeats found in sequence databanks by the T‐REKS program. The database is available at http://bioinfo.montp.cnrs.fr/?r=repeatDB
Enhanced identification of peptides lacking basic residues by LC‐ESI‐MS/MS analysis of singly charged peptides
Authors: Biniossek Martin L. , Schilling Oliver
Published: May 2012

Peptide sequences lacking basic residues (arginine, lysine, or histidine, referred to as “base‐less”) are of particular importance in proteomic experiments targeting protein C‐termini or employing nontryptic proteases such as GluC or chymotrypsin. We demonstrate enhanced identification of base‐less peptides by focused analysis of singly charged precursors in liquid chromatography (LC) electrospray ionization (ESI) tandem mass spectrometry (MS/MS). Singly charged precursors are often excluded from fragmentation and sequence analysis in LC‐MS/MS. We generated different pools of base‐less and base‐containing peptides by tryptic and nontryptic digestion of bacterial proteomes. Focused LC‐MS/MS analysis of singly charged precursor ions yielded predominantly base‐less peptide identifications. Similar numbers of base‐less peptides were identified by LC‐MS/MSanalysis targeting multiply charged precursors. There was little redundancy between the base‐less sequences derived by both MS/MSschemes. In the present experimental outcome, additional LC‐MS/MSanalysis of singly charged precursors substantially increased the identification rate of base‐less sequences derived from multiply charged precursors. In conclusion, LC‐MS/MSbased identification of base‐less peptides is substantially enhanced by additional focused analysis of singly charged precursors.
Proteomic identification of E6AP as a molecular target of tamoxifen in MCF7 cells
Authors: Lochab Savita , Pal Pooja , Kanaujiya Jitendra K. , Tripathi Shashi B. , Kapoor Isha , Bhatt Madan L. B. , Sanyal Sabyasachi , Behre Gerhard , Trivedi Arun K.
Published: May 2012

Tamoxifen (Tam) is most widely used selective estrogen receptor modulator (SERM) for treatment of hormone‐responsive breast cancer. Despite being regularly used in clinical therapy for breast cancer since 1971, the mechanism of Tam action remains largely unclear. In order to gain insights into Tam‐mediated antibreast cancer actions, we applied 2DE and MS based proteomics approach to identify target proteins of Tam. We identified E6‐associated protein, i.e. E6AP (UBE3A) among others to be regulated by Tam that otherwise is upregulated in breast tumors. We confirmed our 2DE finding by immunoblotting and further show that Tam leads to inhibition of E6AP expression presumably by promoting its autoubiquitination, which is coupled with nuclear export and subsequent proteasome‐mediated degradation. Furthermore, we show that Tam‐ and siE6AP‐mediated inhibition of E6AP leads to enhanced G0–G1 growth arrest and apoptosis, which is also evident from significant upregulation of cytochrome‐c, Bax, p21, and PARP cleavage. Taken together, our data suggest that, Tam‐targeted E6AP inhibition is in fact required for Tam‐mediated antibreast cancer actions. Thus, E6AP may be a therapeutic target in breast cancer.
Protein interaction networks in medicine and disease
Authors: Taylor Ian W. , Wrana Jeffrey L.
Published: May 2012

The physical interaction of proteins is subject to intense investigation that has revealed that proteins are assembled into large densely connected networks. In this review, we will examine how signaling pathways can be combined to form higher order protein interaction networks. By using network graph theory, these interaction networks can be further analyzed for global organization, which has revealed unique aspects of the relationships between protein networks and complex biological phenotypes. Moreover, several studies have shown that the structure and dynamics of protein networks are disturbed in complex diseases such as cancer progression. These relationships suggest a novel paradigm for treatment of complex multigenic disease where the protein interaction network is the target of therapy more so than individual molecules within the network.
Computational structural analysis of protein interactions and networks
Authors: Hooda Yogesh , Kim Philip M.
Published: May 2012

Protein interactions have been at the focus of computational biology in recent years. In particular, interest has come from two different communities – structural and systems biology. Here, we will discuss key systems and structural biology methods that have been used for analysis and prediction of protein–protein interactions and the insight these approaches have provided on the nature and organization of protein–protein interactions inside cells.
Interactome mapping for analysis of complex phenotypes: Insights from benchmarking binary interaction assays
Authors: Braun Pascal
Published: May 2012

Protein interactions mediate essentially all biological processes and analysis of protein–protein interactions using both large‐scale and small‐scale approaches has contributed fundamental insights to the understanding of biological systems. In recent years, interactome network maps have emerged as an important tool for analyzing and interpreting genetic data of complex phenotypes. Complementary experimental approaches to test for binary, direct interactions, and for membership in protein complexes are used to explore the interactome. The two approaches are not redundant but yield orthogonal perspectives onto the complex network of physical interactions by which proteins mediate biological processes. In recent years, several publications have demonstrated that interactions from high‐throughput experiments can be equally reliable as the high quality subset of interactions identified in small‐scale studies. Critical for this insight was the introduction of standardized experimental benchmarking of interaction and validation assays using reference sets. The data obtained in these benchmarking experiments have resulted in greater appreciation of the limitations and the complementary strengths of different assays. Moreover, benchmarking is a central element of a conceptual framework to estimate interactome sizes and thereby measure progress toward near complete network maps. These estimates have revealed that current large‐scale data sets, although often of high quality, cover only a small fraction of a given interactome. Here, I review the findings of assay benchmarking and discuss implications for quality control, and for strategies toward obtaining a near‐complete map of the interactome of an organism.
Dissecting the Escherichia coli periplasmic chaperone network using differential proteomics
Authors: Denoncin Katleen , Schwalm Jaclyn , Vertommen Didier , Silhavy Thomas J. , Collet Jean‐Francois
Published: May 2012

β‐Barrel proteins, or outer membrane proteins (OMPs), perform many essential functions in Gram‐negative bacteria, but questions remain about the mechanism by which they are assembled into the outer membrane (OM). In Escherichia coli, β‐barrels are escorted across the periplasm by chaperones, most notably SurA and Skp. However, the contributions of these two chaperones to the assembly of the OM proteome remained unclear. We used differential proteomics to determine how the elimination of Skp and SurA affects the assembly of many OMPs. We have shown that removal of Skp has no impact on the levels of the 63 identified OM proteins. However, depletion of SurA in the skp strain has a marked impact on the OM proteome, diminishing the levels of almost all β‐barrel proteins. Our results are consistent with a model in which SurA plays a primary chaperone role in E. coli. Furthermore, they suggest that while no OMPs prefer the Skp chaperone pathway in wild‐type cells, most can use Skp efficiently when SurA is absent. Our data, which provide a unique glimpse into the protein content of the nonviable surA skp mutant, clarify the roles of the periplasmic chaperones in E. coli.
Effects of acidity and emulsifier concentration on the distribution of vitamin C in a model food emulsion
Authors: Pastoriza‐Gallego María José , Losada‐Barreiro Sonia , Bravo‐Díaz Carlos
Published: May 2012

We have analyzed the effects of acidity and emulsifier concentration on the distribution of ascorbic acid or vitamin C (VC) in a model emulsion prepared by mixing octane, acidic (HCl) water and the non‐ionic surfactant hexaethyleneglycol monododecyl ether (C12E6). VC is oil insoluble, and only the partition constant between the interfacial and aqueous regions (PWI) is needed to describe its distribution within the emulsion. The PWI values are calculated from the kinetic analyses of the variation of the observed rate constant (kobs) determined electrochemically for the reaction between the hydrophobic 4‐hexadecylbenzenediazonium (16‐ArN2+) ions and VC with the emulsifier concentration. The determined PWI values (PWI = 4–25) are low in comparison with those obtained for more hydrophobic antioxidants like vitamin E, and pH dependent, decreasing upon decreasing the acidity of the medium. These low values are reflected in the distribution of VC so that a large fraction (70%) is located in the aqueous region at low emulsifier concentrations. At a given pH, the %VC in the aqueous region decreases upon increasing the emulsifier concentration; meanwhile, at a given emulsifier concentration %VC increases upon lowering the acidity. The intrinsic rate constants in the interfacial region kI for the reaction between 16‐ArN2+ and VC have also been determined at different acidities. Their variation with the pH follows an upward bend curve, suggesting an inverse dependence of kI with the acidity of the medium, in keeping with the proposed mechanism for the reaction. The results may be of some interest to the food and pharmaceutical industries because of the extensive use of VC as antioxidant or preservative and because of the health benefits of VC. Copyright © 2012 John Wiley & Sons, Ltd.
Tuning the sugar‐response of boronic acid block copolymers
Authors: Cambre Jennifer N. , Roy Debashish , Sumerlin Brent S.
Published: May 2012

A detailed study of the pH‐ and sugar‐responsive behavior of poly(3‐acrylamidophenylboronic acid pinacol ester)‐b‐poly(N,N‐dimethylacrylamide) (PAPBAE‐b‐PDMA) block copolymers is presented. Reversible addition‐fragmentation chain transfer (RAFT) polymerization of the pinacol ester of 3‐acrylamidophenylboronic acid resulted in homopolymers with molecular weights between 12,000 and 37,000 g/mol. The resulting homopolymers were employed as macro‐chain transfer agents during the polymerization of N,N‐dimethylacrylamide (DMA). Successful chain extension and removal of the pinacol protecting groups to yield poly(3‐acrylamidophenylboronic acid)‐b‐PDMA (PAPBA‐b‐PDMA) with free boronic acid moieties resulted in pH‐ and sugar‐responsive block copolymers that were subsequently investigated for their behavior in aqueous solution. The PAPBA‐b‐PDMA block copolymers were capable of solution self‐assembly due to the PAPBA block being water‐insoluble below its pKa. The resulting aggregates were demonstrated to solubilize and release model hydrophobic compounds, as demonstrated by fluorescence studies. Dissociation of the aggregates was induced by raising the pH above the pKa of the boronic acid residues or by adding sugars capable of forming boronate esters. Aggregate size, dissociation kinetics, and the effect of various sugars were considered. The critical sugar concentration needed to induce aggregate dissociation was tuned by incorporation of hydrophilic DMA units within the PAPBA responsive segment to yield PDMA‐b‐poly(3‐acrylamidophenylboronic acid‐co‐DMA) block copolymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
A Simple Hydrothermal Method for the Growth of ZnO Crystals
Authors: Peng Yingzi , Huo Dexuan , Zheng Liang , Qian Zhenghong
Published: May 2012

ZnO microstructures have been grown from zinc chloride (ZnCl2) and ammonia solution at 100 °C for 1 – 24 hours. X‐ray diffraction, scanning electron microscope and field‐emission scanning microscope were utilized to investigate the structural properties and morphology of the ZnO crystals. Structural investigations show that phase‐pure hexagonal structure ZnO has been successfully synthesized, and the hexagonal structure ZnO can be achieved in solutions with an appropriate range of concentrations. Under our experimental conditions, several different morphologies of ZnO structures were obtained, including flower‐like and bar flower‐like. The relationship between the morphology and experimental conditions are discussed.
Experimental Study on Powder Flowability Using Vibration Shear Tube Method
Authors: Zainuddin Imran M. , Yasuda Masatoshi , Horio Takehiko , Matsusaka Shuji
Published: May 2012

The flowability of powders with different mass median diameters ranging from micrometers to nanometers was measured using the vibration shear tube method. In the measurement system used in this study, the powder was discharged through a narrow gap between a vibrating tube edge and a flat bottom surface, where each particle could experience high shear forces to overcome the adhesion and friction forces. The vibration amplitude was increased during the measurement, and the mass of particles discharged was measured at constant time intervals. From the relationship between the mass flow rate and the vibration acceleration, static and dynamic properties of the powders were evaluated using the critical vibration acceleration, characteristic mass flow rate, and gradient of mass flow rate. The correlation between the static and dynamic properties was studied in detail.
Influence of the annealing temperature on CuAlxGa1−xSe2 thin films obtained by selenization
Authors: López‐García J. , Guillén C. , Herrero J.
Published: May 2012

CuAlxGa1−xSe2 (CAGS) is an attractive wide‐bandgap chalcopyrite for buffer and top cell in tandem solar cells avoiding the use of expensive In. Polycrystalline CAGS thin films with chalcopyrite structure and strongly oriented along the (112) plane have been obtained by a sequential process of vacuum evaporation and selenization, with different x values ranging from 0 to 1. The temperature of selenization has been varied between 450 and 550 °C and it has resulted on a critical parameter in the complete and homogeneous formation and crystalline quality of the CAGS thin films. The proportion of Al(x) also affects the temperature required for selenization. At least 500 °C is necessary to obtain complete formation of CAGS for x > 0.1 whereas for x ≤ 0.1 the formation takes place in a wide range of annealing temperatures. Resistivity, roughness, band gap energy, texture coefficient C112 and crystallite size tend to increase as the selenization or annealing temperature increases. CAGS thin film properties are optimized at 525 °C for high Al proportions for which some deterioration proceeded at higher temperatures whereas at low Al proportions, a similar behaviour for 525 and 550 °C is observed.
Nanostructured thin film silicon solar cells efficiency improvement using gold nanoparticles
Authors: Pudasaini Pushpa Raj , Ayon Arturo A.
Published: May 2012

We report the computational modeling of localized surface plasmon effects arising on gold (Au) nanoparticles deposited on silicon nanohole (SiNH) textured surface for thin film silicon solar cells application. Detailed balance analysis is carried out for the limiting efficiency of an optimized SiNH array textured surface in combination with the surface and bottom‐of‐a‐trench Au nanoparticle array described herein. We found that for the proposed geometry of the solar cell, the short circuit current density (JSC) and the power conversion efficiency (PCE) are 31.57 mA/cm2 and 25.42%, respectively, that compare favorably to the predicted JSC and PCE values of 25.45 mA/cm2 and 20.87% for an optimized SiNH textured surface without Au nanoparticles. We optimized the silicon dioxide/silicon nitride (SiO2/Si3N4) stack as a passivation layer, retaining the higher optical absorption. The scattering of incident radiation by the Au nanoparticles near their localized plasmon resonance is responsible for higher optical absorption and hence the higher predicted values for JSC and PCE.
Influence of pulsed laser annealing on the optical properties of ZnO nanorods
Authors: Lin T. N. , Huang C. P. , Shu G. W. , Shen J. L. , Hsiao C. S. , Chen S. Y.
Published: May 2012

The effect of pulsed laser annealing (PLA) on the photoluminescence (PL) properties of ZnO nanorods was investigated. As the fluence of pulsed laser increases, the UV PL in ZnO nanorods shows a general increasing trend, except at a range of fluences from 10 to 70 mJ/cm2. It is found that the treatment with the PLA at the fluence of 70 mJ/cm2 leads to a larger improvement of crystalline properties than that with rapid thermal annealing (RTA). The relationship between PL intensity and fluence of pulsed lasers can be well explained by a combination of the deterioration in surface crystallinity and the increased donor densities after PLA.
Effect of the pn junction engineering on Si microwire‐array solar cells
Authors: Dalmau Mallorquí A. , Epple F. M. , Fan D. , Demichel O. , Fontcuberta i Morral A.
Published: May 2012

We report on the impact of the doping concentration design on the performance of silicon microwire arrays as photovoltaic devices. We have fabricated arrays with different p‐ and n‐doping profiles and thicknesses, obtaining mean efficiencies as high as 9.7% under AM 1.5G solar illumination. The results reveal the importance of scaling the microwire diameter with the depletion width resulting from doping concentrations. The doping of the core should be kept low in order to reduce bulk recombination. Furthermore, the thickness of the n‐shell should be kept as thin as possible to limit the emitter losses.
Band structure of magneto‐metallo‐dielectric photonic crystals with hybrid one‐ and two‐dimensional periodicity
Authors: Reyes‐Ayona E. , Halevi P.
Published: May 2012

We calculate the band structure of a magneto‐metallo‐dielectric photonic crystal (PC) with hybrid one‐ and two‐dimensional periodicity. Namely, the permittivity (permeability) is periodic in a plane (single direction). The metallic and magnetic properties are described, respectively, by means of the Drude model and a specific permeability model for Barium‐M ferrite. Because of the dispersion of both the permeability and the permittivity, we obtain a non‐standard eigenvalue problem which is possible to solve by means of a linearization technique. We found that the first band of this PC is very sensitive to the filling fraction of the magnetic component: by changing this fraction from 0.20 to 0.16 the slope – and effective index of refraction – changes from positive to negative.
Bonferroni‐based correction factor for multiple, correlated endpoints
Authors: Shi Qian , Pavey Emily S. , Carter Rickey E.
Published: May 2012

Multiple testing and its impact on the type I and type II error rates are frequently discussed in the statistical and biomedical literature. The Bonferroni adjustment is one of the most widely used approaches, yet it suffers from poor statistical performance when there are correlated test statistics. For example, it is criticized to be too conservative. Nonetheless, part of the strong appeal of the Bonferroni approach is the straightforward implementation and relatively intuitive explanation. In this manuscript, a novel adaptation to the traditional Bonferroni approach that accounts for correlated data is proposed. A simple correction factor based on intraclass correlation is applied to the standard Bonferroni method to overcome the shortcomings of the standard Bonferroni adjustment yet maintains its advantages. The method is motivated by an early phase clinical trial examining the effect of a study medication on marijuana craving, which is commonly quantified into four correlated constructs. A detailed simulation study demonstrated that the proposed approach is statistically sound and appropriate for a wide range of common settings. Copyright © 2012 John Wiley & Sons, Ltd.
Impact of safety monitoring on error probabilities of binary efficacy outcome analyses in large phase III group sequential trials
Authors: Weng Yanqiu , Zhao Wenle , Palesch Yuko
Published: May 2012

In phase III clinical trials, some adverse events may not be rare or unexpected and can be considered as a primary measure for safety, particularly in trials of life‐threatening conditions, such as stroke or traumatic brain injury. In some clinical areas, efficacy endpoints may be highly correlated with safety endpoints, yet the interim efficacy analyses under group sequential designs usually do not consider safety measures formally in the analyses. Furthermore, safety is often statistically monitored more frequently than efficacy measures. Because early termination of a trial in this situation can be triggered by either efficacy or safety, the impact of safety monitoring on the error probabilities of efficacy analyses may be nontrivial if the original design does not take the multiplicity effect into account. We estimate the actual error probabilities for a bivariate binary efficacy–safety response in large confirmatory group sequential trials. The estimated probabilities are verified by Monte Carlo simulation. Our findings suggest that type I error for efficacy analyses decreases as efficacy–safety correlation or between‐group difference in the safety event rate increases. In addition, although power for efficacy is robust to misspecification of the efficacy–safety correlation, it decreases dramatically as between‐group difference in the safety event rate increases. Copyright © 2012 John Wiley & Sons, Ltd.
A novel control architecture for physiological tremor compensation in teleoperated systems
Authors: Ghorbanian A. , Zareinejad M. , Rezaei S.M. , Sheikhzadeh H. , Baghestan K.
Published: May 2012

Background

Telesurgery delivers surgical care to a ‘remote’ patient by means of robotic manipulators. When accurate positioning of the surgeon's tool is required, as in microsurgery, physiological tremor causes unwanted imprecision during a surgical operation. Accurate estimation/compensation of physiological tremor in teleoperation systems has been shown to improve performance during telesurgery.

Method

A new control architecture is proposed for estimation and compensation of physiological tremor in the presence of communication time delays. This control architecture guarantees stability with satisfactory transparency. In addition, the proposed method can be used for applications that require modifications in transmitted signals through communication channels. Stability of the bilateral tremor‐compensated teleoperation is preserved by extending the bilateral teleoperation to the equivalent trilateral Dual‐master/Single‐slave teleoperation. The bandlimited multiple Fourier linear combiner (BMFLC) algorithm is employed for real‐time estimation of the operator's physiological tremor.

Results

Two kinds of stability analysis are employed. In the model‐base controller, Llewellyn's Criterion is used to analyze the teleoperation absolute stability. In the second method, a nonmodel‐based controller is proposed and the stability of the time‐delayed teleoperated system is proved by employing a Lyapunov function. Experimental results are presented to validate the effectiveness of the new control architecture. The tremorous motion is measured by accelerometer to be compensated in real time. In addition, a Needle‐Insertion setup is proposed as a slave robot for the application of brachytherapy, in which the needle penetrates in the desired position. The slave performs the desired task in two classes of environments (free motion of the slave and in the soft tissue).

Conclusion

Experiments show that the proposed control architecture effectively compensates the user's tremorous motion and the slave follows only the master's voluntary motion in a stable manner. Copyright © 2012 John Wiley & Sons, Ltd.
Milling of rice grains: The roles of starch structures in the solubility and swelling properties of rice flour
Authors: Hasjim Jovin , Li Enpeng , Dhital Sushil
Published: May 2012

Rice flours with different particle sizes and degrees of damaged starch granules were produced by hammer milling and cryogenic milling of rice grains, where degradation of starch molecules was evident in the hammer‐milled flours, but not in the cryogenically milled flours. The solubility and swelling properties of the resulting rice flours were determined in cold (30°C) and hot water (90°C). The cold‐ and hot‐water starch solubility was strongly correlated with the degree of damaged starch granules, and weakly with the particle size of rice flour. No evident correlations were observed between starch solubility and the molecular structures, indicating that molecular degradation by milling process was not the only precondition of increased starch solubility. Possible mechanism for the observed correlations is that increasing surface area and/or exposure of loosely packed inner part of starch granules with increasing degree of damaged starch granules allowed more starch molecules to leach out in cold and hot water. Furthermore, the cold‐water swelling of rice flour was strongly correlated with the degree of damaged starch granules, possibly due to the rapid hydration of damaged starch granules, whereas the hot‐water swelling did not show any correlations with flour particle size and granular and molecular starch structures. The results have provided better insights in the relationship between starch structures and solubility and swelling properties of rice flour, which can be used to improve the manufacture and selection criteria of rice flour for better products.
Systems engineering of Omid, the first domestic satellite of the I.R. of Iran
Authors: Shahrabi H. , Pourtakdoust Seid H. , Abolghasemi M. , Tivay M.
Published: May 2012

In keeping with the continuing effort toward the development of a domestic space research and development program in recent years, the Omid National Satellite (ONS) is the first domestically manufactured satellite from the Islamic Republic of Iran. As a technology demonstration, it was launched and utilized successfully in February 2009. Despite the simple mission of the ONS, because it was the first full‐scale successful space deployment experience for the country, the domestic manufacturing capabilities for satellite and launch technologies were boosted. More importantly, the country's domestic platform for future space projects was established. Considering the important role of systems engineering (SE) in the localization of the Iranian space industry, this paper aims to present the ONS space program in terms of its SE management , conceptual design, subsystem descriptions with technical specifications, integration, testing, and development. The operational in‐orbit aspects will also be described. The project generated a high level of hope and a sense of achievement among the many skilled national engineers who worked on the project. The specific and general lessons learned that are emphasized in this paper will be incorporated into the country's future space programs and will be used to support the development of the next generation of small satellites. © 2012 Wiley Periodicals, Inc. Syst Eng
A versatile method for preparation of hydrated microbial–latex biocatalytic coatings for gas absorption and gas evolution
Authors: Gosse Jimmy L , Chinn Mari S , Grunden Amy M , Bernal Oscar I , Jenkins Jessica S , Yeager Chris , Kosourov Sergey , Seibert Michael , Flickinger Michael C
Published: May 2012

We describe a latex wet coalescence method for gas-phase immobilization of microorganisms on paper which does not require drying for adhesion. This method reduces drying stresses to the microbes. It is applicable for microorganisms that do not tolerate desiccation stress during latex drying even in the presence of carbohydrates. Small surface area, 10–65 μm thick coatings were generated on chromatography paper strips and placed in the head-space of vertical sealed tubes containing liquid to hydrate the paper. These gas-phase microbial coatings hydrated by liquid in the paper pore space demonstrated absorption or evolution of H2, CO, CO2 or O2. The microbial products produced, ethanol and acetate, diffuse into the hydrated paper pores and accumulate in the liquid at the bottom of the tube. The paper provides hydration to the back side of the coating and also separates the biocatalyst from the products. Coating reactivity was demonstrated for Chlamydomonas reinhardtii CC124, which consumed CO2 and produced 10.2 ± 0.2 mmol O2 m−2 h−1, Rhodopseudomonas palustris CGA009, which consumed acetate and produced 0.47 ± 0.04 mmol H2 m−2 h−1, Clostridium ljungdahlii OTA1, which consumed 6 mmol CO m−2 h−1, and Synechococcus sp. PCC7002, which consumed CO2 and produced 5.00 ± 0.25 mmol O2 m−2 h−1. Coating thickness and microstructure were related to microbe size as determined by digital micrometry, profilometry, and confocal microscopy. The immobilization of different microorganisms in thin adhesive films in the gas phase demonstrates the utility of this method for evaluating genetically optimized microorganisms for gas absorption and gas evolution.
La consultation psychologique dans l’indication d’une prothèse pénienne : une expérience originale de complémentarité médicopsychologique
Authors: Mormont C. , Andrianne R.
Published: May 2012

Au Centre d’Étude et de Traitement des Insuffisances Sexuelles Masculines (CETISM) de notre département universitaire d’urologie, une consultation psychologique est systématiquement programmée lorsque la prothèse pénienne est considérée par le patient — et l’urologue — comme une solution possible de sa défaillance érectile.

Cette consultation comporte trois objectifs essentiels: repérer les cas — rares — de contre-indication psychopathologique, compléter l’information déjà donnée au patient lors des consultations médicochirurgicales et explorer les aspects relationnels, affectifs, cognitifs et érotiques susceptibles d’intervenir dans la prise de décision et dans l’intégration de la solution prothétique.

Elle vise aussi et surtout à rendre à l’homme sa position centrale, active, non seulement dans la prise de décision, mais encore dans l’élaboration d’un projet de vie qui tient compte de cette décision (positive ou négative), position qu’il a souvent perdue au moment où il est devenu « impuissant ».
Radiocarbon chronology of Holocene glacial and climatic events in southeastern Altai (Central Asia)
Authors: Agatova A.R. , Nazarov A.N. , Nepop R.K. , Orlova L.A.
Published: May 2012

The geomorphological studies and radiocarbon dating of moraine complexes and the tree line within the North Chuya Ridge, along with active slope processes, soil formation, and peat formation in southeastern Gorny Altai, constrain the age of the main glacial and climatic events in this area at 7 ka to the first half of the 19th century. It is for the first time in the history of Altai studies that 57 absolute dates were obtained for glaciation in a vast but climatically and neotectonically homogeneous area. The new data refute the conventional idea that the Holocene glaciation in this mountain land comprised eight stages of the gradual retreat of the Late Würm (Sartan) glaciation. Also, they evidence that glaciation in the upper parts of the troughs retreated almost completely no later than 7 ka and valley glaciers in southeastern Altai were activated many times in the second half of the Holocene. Data are given on the morphology and age of three moraine generations reflected in the topography. A combination of temperature minima and humidity maxima led to a catastrophically rapid and the largest (up to 5–6 km) ice advance at the Akkem Stage (4.9–4.2 ka). In addition to the radiocarbon data, the time limits of the Historical stage (2.3–1.7 ka) were defined more precisely using dendrochronological and archaeological data from Scythian burials of Pazyryk culture in SE Altai. The moraines closest to the present-day glaciers formed at the Aktru Stage (late 13th–middle 19th century). During warm interglacials, the glaciers waned considerably or retreated completely and the zone of recent glaciation was reforested. As a result of progressive aridization in the Holocene, the glaciers in southeastern Altai waned at each successive stage, and their mass balance was not positive during the greatest temperature minimum of the last millennium (middle 19th century).
Orderings and signatures of higher level on multirings and hyperfields
Authors: Gładki Paweł , Marshall Murray
Published: May 2012

Multirings are objects like rings but with multi-valued addition. In the present paper we extend results of E. Becker and others concerning orderings of higher level on fields and rings to orderings of higher level on hyperfields and multirings and, in the process of doing this, we establish higher level analogs of the results previously obtained by the second author. In particular, we introduce a class of multirings called ℓ-real reduced multirings, define a natural reflection A ⇝ Qℓ-red(A) from the category of multirings satisfying to the full subcategory of ℓ-real reduced multirings, and provide an elementary first-order description of these objects. The relationship between ℓ-real reduced hyperfields and the spaces of signatures defined by Mulcahy and Powers is also examined.
Performance of empirical BLUP and Bayesian prediction in small randomized complete block experiments
Authors: FORKMAN J. , PIEPHO H-P.
Published: May 2012

The model for analysis of randomized complete block (RCB) experiments usually includes two factors: block and treatment. If treatment is modelled as fixed, best linear unbiased estimation (BLUE) is used, and treatment means estimate expected means. If treatment is modelled as random, best linear unbiased prediction (BLUP) shrinks the treatment means towards the overall mean, which results in smaller root-mean-square error (RMSE) in prediction of means. This theoretical result holds provided the variance components are known, but in practice the variance components are estimated. BLUP using estimated variance components is called empirical best linear unbiased prediction (EBLUP). In small experiments, estimates can be unreliable and the usefulness of EBLUP is uncertain. The present paper investigates, through simulation, the performance of EBLUP in small RCB experiments with normally as well as non-normally distributed random effects. The methods of Satterthwaite (1946) and of Kenward & Roger (1997, 2009), as implemented in the SAS System, were studied. Performance was measured by RMSE, in prediction of means, and coverage of prediction intervals. In addition, a Bayesian approach was used for prediction of treatment differences and computation of credible intervals. EBLUP performed better than BLUE with regard to RMSE, also when the number of treatments was small and when the treatment effects were non-normally distributed. The methods of Satterthwaite and of Kenward & Roger usually produced approximately correct coverage of prediction intervals. The Bayesian method gave the smallest RMSE and usually more accurate coverage of intervals than the other methods.
Barbara Hepworth and The Tonsillectomy
Authors: Kane Kevin J
Published: May 2012

The Garnett Passe and Rodney Williams Foundation, a major medical research foundation in Melbourne, has recently acquired a hitherto unknown and uncatalogued painting by Dame Barbara Hepworth, the celebrated British sculptor and artist. It is of the Foundation's nominal patron Garnett Passe performing a tonsillectomy, probably at the London Clinic, in 1948. This article gives an account of Barbara Hepworth and her relationships with Garnett Passe and Norman Capener, the two surgeons who introduced her to this subject and who led to the creation of this unique work of art.
‘Take it from the top’: northern conceptions about identity in the western Arctic and beyond
Authors: Robinson Suzanne
Published: May 2012

During the last decades the Arctic has become more central on the world stage. However, despite increased interest how much do people really know about ‘the north’ and the ‘northern people’? The aim of this article is to chronicle a research project by students, who saw themselves as northerners, that used video to capture northerners’ definitions of the north, as well as asking the community about what they wanted newcomers and southern Canada to know about the north. The group also embarked on a new discipline of northerners studying ‘the south’. 43 students interviewed 95 people in the Beaufort Delta, Northwest Territories and 25 people in Edmonton, Alberta. The student researchers’ responses and that of their interviewees are some of the most direct messages on how northerners view their identity and that of their fellow southern Canadians. This project created a video tool to share, educate, and commence a dialogue between people about the north straight from the source.