bluuebunny/crossref_metadata_2025 huggingface dataset:
On a class of singular Trudinger‐Moser type inequalities and its applications
Authors: Marcos do Ó João , de Souza Manassés
Published: August 2011

This paper deals with an improvement of a class of the Trudinger‐Moser inequality with a singular weight associated to the embedding of the standard Sobolev space H10(Ω) into Orlicz spaces for any smooth domain \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\Omega \subset \mathbb {R}^2$\end{document}, in particular for \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\Omega = \mathbb {R}^2$\end{document}. As an application of this result, using the Ekeland variational principle and the mountain‐pass theorem we establish sufficient conditions for the existence and multiplicity of weak solutions for the following class of problems

where a ∈ [0, 2), V(x) is a continuous positive potential bounded away from zero and which can be “large” at the infinity, the nonlinearity f(s) behaves like \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$e^{\alpha s^2}$\end{document} when |s| → +∞ and \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$h \in (H^1(\mathbb {R}^2))^*$\end{document} is a small perturbation. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Obsessive‐compulsive symptoms in primary focal dystonia: A controlled study
Authors: Barahona‐Corrêa Bernardo , Bugalho Paulo , Guimarães João , Xavier Miguel
Published: August 2011

Primary focal dystonia is an idiopathic neurological disorder causing involuntary muscle contraction. Its pathophysiology probably involves the basal ganglia and cortical‐basal pathways. Primary dystonia appears to be associated with significant obsessive‐compulsive symptoms, but evidence remains scarce and contradictory. We addressed the following research questions: (1) Do primary dystonia patients have high obsessive‐compulsive symptom scores? (2) Are these symptoms more severe in dystonia than in controls with equivalent peripheral neurological disorders? and (3) Is psychopathology different in botulinum toxin‐treated and ‐untreated dystonia patients? This work was a cross‐sectional, descriptive, controlled study comprising 45 consecutive patients with primary focal dystonia (i.e., blepharospasm, spasmodic torticollis, or writer's cramp) 46 consecutive patients with hemifacial spasm, cervical spondylarthropathy, or carpal tunnel syndrome, and 30 healthy volunteers. Assessment included the DSM‐IV based psychiatric interview, Symptom Checklist 90R, Yale‐Brown Obsessive‐Compulsive Scale and Checklist, and the Unified Dystonia Rating Scale. Dystonia patients had higher Yale‐Brown Obsessive‐Compulsive Symptom scores than both control groups. Dystonia patients with obsessive‐compulsive symptom scores above cut‐off for clinical significance predominantly developed hygiene‐related symptoms. Major depression and generalized anxiety disorder were the most frequent psychiatric diagnoses in primary focal dystonia. Obsessive‐compulsive disorder frequency was 6.7%. Primary focal dystonia patients have higher obsessive‐compulsive symptom scores than individuals with similar functional disabilities resulting from other neurological disorders, suggesting that obsessive‐compulsive symptoms in dystonia are not reactive to chronic disability. Dystonic muscle contractions and obsessive‐compulsive symptoms may share a common neurobiological basis related to cortical‐basal dysfunction. Psychopathology, especially obsessive‐compulsive symptoms, should be actively explored and treated in primary focal dystonia. © 2011 Movement Disorder Society
Modeling the Microstructure of Acrylic‐Polyurethane Hybrid Polymers Synthesized by Miniemulsion Polymerization
Authors: Reyes Yuri , Lopez Aitziber , Asua José M.
Published: August 2011

A computer simulation is presented for the prediction of the detailed microstructure of acrylic‐polyurethane hybrid polymers synthesized by miniemulsion polymerization. The simulation considers the polymerization of a mixture of acrylic monomers, one of them having a hydroxyl group, in the presence of a diisocyanate terminated prepolymer and a diol. The simulation approach is able to reproduce the experimental tendency (gel content, sol molecular weight and swelling capability) and provide additional information that is not attainable otherwise, as the distribution of pendant PU chains and dangling acrylic chains and the loop size distribution of the hybrid network. The analysis of such complex structures opens the possibility of tuning the performance of crosslinked emulsion polymers by adjusting their microstructure.

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A Polymerization Kinetics Comparison between a Metallocene Catalyst Activated by Tetrakis(pentafluorophenyl) Borate and MAO for the Polymerization of Ethylene in a Semi‐batch Solution Reactor
Authors: Mehdiabadi Saeid , Soares Joaõ B. P. , Bilbao Daniel , Brinen Jeffrey L.
Published: August 2011

This work investigates the effects of activator species on catalyst reactivity in the semi‐batch, solution polymerization of ethylene using rac‐dimethylsilyl‐bis(indenyl)hafnium dimethyl catalyst. The two activators compared are methylalumoxane and tetrakis(pentafluorophenyl) borate dimethylanilinium salt ([B(C6F5)4]–[Me2NHPh]+). For each of the catalyst/activator systems, monomer and activator concentrations were varied to gain a basic understanding of polymerization kinetics, allowing for direct comparison of each system. Copolymerization experiments involving 1‐octene were also carried out to further investigate the influence of activator type on copolymerization kinetics and products.

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Unimodal Particle Size Distribution Latexes: Effect of Reaction Conditions on Viscosity and Stability at High Solids Content
Authors: Mariz Inês de F. A. , de la Cal José C. , Leiza Jose R.
Published: August 2011

The effect of process variables on the stability and viscosity of high solids content (HSC) latexes (60 wt%) with unimodal particle size distribution (PSD) (centered in 300 nm) synthesized by conventional seeded semibatch emulsion polymerization was investigated. The effect of the use of carboxylic monomers and its type, the concentration and type of surfactants and the pH of the polymerization were considered. It was found that the more stable latexes were produced under basic pH and using carboxylic monomers in the formulation. When carboxylic monomers were not used stable latexes could also be obtained, but using slightly larger concentrations of the anionic surfactant. The use of non‐ionic surfactants in combinations with anionic ones during the synthesis of the latexes was deleterious in all the cases. The viscosity of the latexes was shear thinning and latexes synthesized at basic pH and with higher concentration of surfactant presented relatively higher viscosities.

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Application of Parameter Selection and Estimation Techniques in a Thermal Styrene Polymerization Model
Authors: Woloszyn John D. , McAuley Kimberley B.
Published: August 2011

A model is developed to describe thermally‐initiated polymerization of styrene between 100 and 170 °C. The model accounts for generation and consumption of styrene adduct. Chain transfer to adduct is the only transfer reaction used. Autoacceleration is modeled using the break‐point method of Hui and Hamielec. Using formal ranking and parameter selection techniques that account for parameter sensitivity, correlation and uncertainty, 4 of the 40 model parameters are selected for estimation to improve fit between model predictions and data. After estimation, the model predicts conversion data with a standard error of 5%, and provides excellent fit to a MWD curve obtained at 100 °C. Simulation results confirm that high‐temperature degradation reactions are not important in the temperature range of interest.

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Kinetics and Modeling of Solution ARGET ATRP of Styrene, Butyl Acrylate, and Methyl Methacrylate
Authors: Li Xiaohui , Wang Wen‐Jun , Li Bo‐Geng , Zhu Shiping
Published: August 2011

This work reports a kinetic model for the activator‐regenerated‐by‐electron‐transfer atom‐transfer radical polymerization (ARGET ATRP) and its verification by the experimental data of solution ARGET ATRP of styrene, methyl methacrylate, and butyl arylate from literatures. The effects of ATRP equilibrium constant K and apparent reducing rate coefficient kr on the ARGET ATRP kinetics are investigated. A highly active initiation/catalyst system with a large K results in a poor control of the polymerization while an increased kr promotes the polymerization rate but the formation of dead polymer chains. Reducing agent with a moderate kr gives good control over ARGET ATRP. It is not feasible to use a moderate catalyst system for the ARGET ATRP of highly active monomers.

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Degenerative Joint Disease and Social Status in the Terminal Late Archaic Period (1000–500 b.c.) of Ohio
Authors: Woo Eun Jin , Sciulli Paul W.
Published: August 2011

This research presents an analysis of the inferred Late Archaic social structure in Ohio based on degenerative joint disease (DJD, also known as osteoarthritis) and mortuary practices. We tested the hypothesis that mechanical loading involving physical activities is differentially distributed in a population along levels or types of social stratification. This hypothesis was investigated via statistical treatment of DJD as a skeletal stress marker of activity, its occurrence by age and sex, an association with grave goods, and spatial distribution in terminal Late Archaic cemeteries. The skeletal samples used in this study came from three cemeteries, the Boose, Kirian‐Treglia (KT), and Duff sites, dating to the Ohio terminal Late Archaic period.

In general, the high overall prevalence of DJD in these people indicates that this population led a rigorous life. This study hypothesized that the burials in the Late Archaic period in Ohio might be socially patterned as evidenced from the unequal distribution of grave goods and skeletal variability in DJD. Nevertheless, the analyses suggest that there is no statistical association between DJD and mortuary practices including grave goods and burial location in a cemetery. As observed in numerous hunter–gatherer populations, the societies in our sample were also characterized by the absence of a marked social stratification. The results suggest that there were only ‘natural inequalities’ in Late Archaic societies due to biological factors, such as age and sex. Copyright © 2011 John Wiley & Sons, Ltd.
Managing dopamine agonist withdrawal syndrome in Parkinson's disease
Authors: Lindahl Andrea J , MacMahon Douglas G
Published: August 2011

Dopamine agonist withdrawal syndrome (DAWS) has recently been named in the Archives of Neurology. It describes a cluster of symptoms occurring in Parkinson's disease patients with impulse control disorders on tapering down or withdrawal of their dopamine agonist. Drs Lindahl and MacMahon discuss the risk factors for the development of DAWS and some approaches to its management. Copyright © 2011 Wiley Interface Ltd
Psychiatric diagnosis needs a more scientific approach
Authors: Titmarsh Steve , Goodyer Ian
Published: August 2011

A more rigorous and scientific approach to characterisation and diagnosis of mental illness, particularly among children, could help reduce the number of patients who do not respond to treatment. That was the view put forward by Professor Ian Goodyer, Professor of Child and Adolescent Psychiatry at Cambridge University in his Keynote Lecture at the 10th Latest Advances in Psychiatry Symposium held in London in March. Steve Titmarsh reports. Copyright © 2011 Wiley Interface Ltd
Comparison of a memory service database with primary care dementia registers
Authors: O'Kelly Allison , Richards Giles
Published: August 2011

Under the Quality Outcome Framework (QOF), points are awarded to GP practices that keep a dementia register and record patient reviews. The aim of this audit was to compare the East Cornwall Memory Service's database of diagnosed patients against the QOF registers for dementia held by nine GP practices in East Cornwall. Copyright © 2011 Wiley Interface Ltd
A novel protocol for the preparation of uniform polymer microspheres with high yields through step polymerization of isophorone diisocyanate
Authors: Jiang Xubao , Kong Xiang Zheng , Zhu Xiaoli
Published: August 2011

Uniform polymer microspheres with neat surface are of high interests. Precipitation polymerization of vinylic monomers remains a very limited process owing to very low monomer concentration allowed. Here, a fully novel protocol for the production of uniform polymeric microspheres is presented. Using one single monomer, isophorone diisocyanate, highly monodisperse polyurea microspheres were achieved with very high yield in a very short time period via precipitation polymerization in water–acetone mixed solvent. Results demonstrated that the ratio of water–acetone and polymerization temperature played important roles in the process. The size of the microspheres was readily adjustable by varying monomer concentration, water/acetone ratio or polymerization temperature. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Poly(allyl glycidyl ether)‐A versatile and functional polyether platform
Authors: Lee Bongjae F. , Kade Matthew J. , Chute Jerred A. , Gupta Nalini , Campos Luis M. , Fredrickson Glenn H. , Kramer Edward J. , Lynd Nathaniel A. , Hawker Craig J.
Published: August 2011

Allyl glycidyl ether, polymerized from potassium alkoxide/naphthalenide initiators under both neat and solution conditions was shown to be a highly controlled process. In both cases, molar masses (10–100 kg/mol) were determined by the reaction stoichiometry, and low polydispersity indices (1.05–1.33) could be obtained with a full understanding of the dominant side reaction, isomerization of the allyl side chain, being developed. The degree of isomerization of allyl to cis‐prop‐1‐enyl ether groups (0–10% mol) was not correlated to the molar mass or polydispersity of the polymer but was dictated by the polymerization temperature. This allows the extent of isomerization to be reduced to essentially zero under either melt or solution conditions at polymerization temperatures of less than 40 °C. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Controlled epoxidation of poly(styrene‐b‐isoprene‐b‐styrene) block copolymer for the development of nanostructured epoxy thermosets
Authors: Garate Hernan , Mondragon Iñaki , Goyanes Silvia , D'Accorso Norma B.
Published: August 2011

To be used as templates for nanostructured thermosets, a commercial poly(styrene‐b‐isoprene‐b‐styrene) (SIS) block copolymer (BCP) was epoxidized by three different epoxidation procedures. An exhaustive analysis of methodologies using metal catalyzed/hydrogen peroxide, dimethyldioxirane (DMDO), and meta‐chloroperbenzoic acid (m‐CPBA) was performed to obtain reactive BCPs. The DMDO approach was the best strategy to obtain highly epoxidized SIS BCP (85 mol %) without formation of side products. Careful control in BCP epoxidation by metal catalyzed/hydrogen peroxide and m‐CPBA approaches led to a maximum epoxidation degree (ED) of approximately 60 mol % without the formation of side products. The ED by metal catalyzed/hydrogen peroxide strategy could be further increased to 69 mol %, but a significant amount of crosslinking, ring opening, and polymer chain scission reactions were detected by spectroscopic and chromatographic techniques. The miscibility of epoxidized BCPs with diglycidyl ether of bisphenol‐A epoxy system before and after curing was analyzed to develop nanostructured epoxy thermosets. For ED higher than 69 mol %, BCPs were miscible, while those with lower ED presented macrophase separation. Highly epoxidized BCPs obtained by the DMDO methodology were successfully used to obtain ordered nanodomains inside the epoxy matrix, as determined by atomic force microscopy. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Modulating catalytic activity of polymer‐based cuAAC “click” reactions
Authors: Bell Craig A. , Jia Zhongfan , Perrier Sébastien , Monteiro Michael J.
Published: August 2011

The copper(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction is used to synthesize complex polymer architectures. In this work, we demonstrate the control of this reaction at 25 °C between polystyrene (PSTY) chains through modulating the catalytic activity by varying the combinations of copper source (i.e., Cu(I)Br or copper wire), ligand (PMDETA and/or triazole ligand), and solvent (toluene or DMF). The fastest rate of CuAAC was found using Cu(I)Br/PMDETA ligand in toluene, reaching near full conversion after 15 min at 25 °C. For the same catalysts system, DMF also gave fast rates of “click” (95% conversion in 25 min). Cu(0) wire in toluene gave a conversion of 98% after 600 min, a much higher rate than that observed for the same catalyst system used in DMF. When the PSTY had a chemically bound triazole ring close to the site of reaction, the rate of CuAAC in toluene increased significantly, 97% in 180 min at 25 °C, in agreement with our previously published results. This suggests that rapid rates can be obtained using copper wire and will have direct applications to the synthesis of compound where air, removal of copper, and reuse of the copper catalyst are required. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Homogeneous radical polymerization of 2‐hydroxyethyl methacrylate mediated by cyclometalated cationic Ruthenium(II) complexes with PF6− and Cl− in protic media
Authors: Diaz Maria Ortencia Gonzalez , Morales Salvador Lopez , Lagadec Ronan Le , Alexandrova Larissa
Published: August 2011

Cationic coordinatively saturated complexes of ruthenium(II), [Ru(o‐C6H4‐2‐py)(phen)(MeCN)2]+, bearing different counterions of PF6− and Cl− have been used in the radical polymerization of 2‐hydroxyethyl methacrylate in protic media and acetone under homogeneous conditions. Exchange of PF6− by Cl− increases the solubility of the complex in water. Both complexes led to the fast polymerization under mild conditions, but control was achieved only in methanol and acetone and was better for the complex with Cl−. The polymerization accelerated in aqueous media and proceeded to a high conversion even with a monomer/catalyst = 2000/1, but without control. Polymerization mediated by complex bearing Cl− was slower in protic solvents but faster in acetone and always resulted in lower molecular weight polymers. Thus, the nature of the anion strongly affected the catalytic activity of the complexes and may serve as way of fine‐tuning the catalytic properties. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Donor–acceptor diethynylsilane oligomers: A second‐order nonlinear optical material
Authors: Machado Ana E. De A. , Souza Leonardo A. De , Dos Santos Hélio F. , Almeida Wagner B. De
Published: August 2011

The interest in the study of oligomers has been motivated mainly because of their solubility in common solvents and also their capacity to be crystallized, which allowed for chemical processing leading to important applications in the area of material sciences. In this work, we carried out an investigation of polydiethynylsilane (PDES) decamers substituted with electron donor (D) and acceptor (A) groups, which is certainly of relevance, once PDES itself is known to display large third‐order optical susceptibility. Therefore, density functional theory calculations of static first hyperpolarizability (β) were performed using various functionals with the 6‐31G(d) basis set along with correlated MP2 calculation used as reference for comparison. The influence of A and D substituents on the magnitude of β was investigated by matching the acceptor (dicyanovinyl, nitrobenzene) and donor (propyl, propoxy, and phenylamine) groups attached at both ends of the oligomer. The largest β value was predicted for the derivative having the phenylamine and dicyanovinyl groups, which is around 30 times the relative value for the nonsubstituted decamer, what is a very impressive enhancement reported for the first time in the literature, strongly suggesting that disubstituted diethynylsilane decamers are potential building blocks for molecular‐based materials with second‐order nonlinear responses. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1410–1419, 2011
Modification of Polydimethylsiloxane Thin Films in H2 Radio‐frequency Plasma Investigated by Infrared Reflection Absorption Spectroscopy
Authors: Danilov Vladimir , Wagner Hans‐Erich , Meichsner Jürgen
Published: August 2011

The plasma modification of polydimethylsiloxane (PDMS) thin films was studied by means of Fourier Transform Infrared Reflection Absorption Spectroscopy (FT‐IRRAS). The spin‐coated PDMS films (10–175 nm) were prepared on aluminium coated glass substrates, and their thickness was measured by spectroscopic ellipsometry. The direct hydrogen RF plasma interaction with PDMS is compared with the hydrogen plasma radiation, only. The evolution of the thin film IR absorption spectrum was monitored, and the changes of PDMS characteristic absorption bands as well as the formation of new bands are discussed. In particular, the appearance of a new band at 1 230 cm−1 was observed, and it was identified as LO phonon band of SiOx.

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Ion and Vacuum Ultraviolet Photon Beam Effects in 193 nm Photoresist Surface Roughening: The Role of the Adamantyl Pendant Group
Authors: Chung Ting‐Ying , Graves David B. , Weilnboeck Florian , Bruce Robert L. , Oehrlein Gottlieb S. , Li Mingqi , Hudson Eric A.
Published: August 2011

Previous studies have identified a synergistic effect of ion bombardment, vacuum ultraviolet (VUV) radiation, and moderate substrate heating in 193 nm photoresist (PR) surface roughening. The degree of surface roughness is comparable to that obtained from typical plasma etch processes. Ion bombardment results in a carbon‐rich surface layer with a thickness of a few nanometers, and VUV radiation causes bulk modification to a depth of about 100 nm. The probable difference in mechanical properties between the carbon‐rich surface layer and the softened underlayer is proposed to be the main cause of PR surface roughening. In the same vacuum beam apparatus, we further characterize the roughening of associated homopolymers: poly‐(2‐methyl‐2‐adamantyl methacrylate) (p‐MAMA) and poly‐(R‐functionalized adamantyl methacrylate) (p‐RAMA). MAMA is the leaving group, and RAMA is the polar group in 193 nm PR, respectively. Monitored by ex situ transmission FTIR and in situ mass spectrometry, p‐MAMA undergoes temperature‐dependent bulk degradation during VUV exposure while p‐RAMA is relatively insensitive to VUV. We identify the adamantyl leaving group as one of the main photolysis products from p‐MAMA. Higher substrate temperatures increase the vapor pressure and facilitate desorption of the detached adamantyl leaving group. The adamantane loss/detachment shows strong correlation to PR surface roughening. A bi‐layer wrinkling mechanism is proposed to qualitatively explain the observed surface roughening. The present results demonstrate that PR leaving group content and structure can couple to plasma etching processes and strongly alter post‐etch surface morphology.

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Parent‐reported ISAAC written questionnaire may underestimate the prevalence of asthma in children aged 10–12 years
Authors: Kim Myoung Hee , Kwon Ji‐Won , Kim Hyo Bin , Song Younghwa , Yu Jinho , Kim Woo‐Kyung , Kim Byeong‐Ju , Lee So Yeon , Kim Kyoung‐Won , Ji Hye‐Mi , Kim Kyu‐Earn , Shin Yee‐Jin , Kim Ho , Hong Soo‐Jong
Published: August 2011

Objectives

The aim of the present study was to compare the validity of the International Study of Asthma and Allergies in Childhood (ISAAC) written (WQ) and audiovisual questionnaires (AVQ 3.0) in two age‐groups (10–12 and 13–15 years, respectively).

Methods

The 13–15 year olds performed the self‐completed the WQ and AVQ on the same day. The 10–12 year olds performed the self‐completed the AVQ and the parent‐completed WQ was completed by their parents. The methacholine challenge test was conducted in 10–12 year olds from one elementary school.

Results

In 10–12 year olds, the AVQ detected a generally higher prevalence of asthma symptoms than WQ. In 13–15 year olds, this was reversed. In 10–12 year olds, poor agreement was found between the parent‐completed WQ and the self‐reported AVQ. In 13–15 year olds, moderate agreement was found between the self‐reported WQ and AVQ. Low sensitivity was found, in predicting bronchial hyper‐responsiveness (BHR) for all questions of both WQ and AVQ in 10–12 year olds. However, the AVQ had slightly higher sensitivity than WQ, with the exception of wheeze ever, although it was not statistically significant.

Conclusion

The ISAAC AVQ may be another effective instrument for assessing the prevalence of asthma symptoms in children aged 10–12 years, whereas the parent‐reported‐WQ may underestimate the prevalence of asthma symptoms in this age‐group. Pediatr Pulmonol. 2012; 47:36–43. © 2010 Wiley Periodicals, Inc.
A comparison of fluoroscopic airway screening with flexible bronchoscopy for diagnosing tracheomalacia
Authors: Sanchez M.O. , Greer M.C. , Masters I.B. , Chang A.B.
Published: August 2011

Background

Flexible bronchoscopy (FB) is the gold standard method of diagnosing tracheomalacia but it is not always feasible in settings with limited resources. Fluoroscopy is sometimes performed as an alternative diagnostic tool but there are no prospective studies that have evaluated the diagnostic accuracy of airway fluoroscopy for tracheomalacia using a‐priori definitions. We determined the sensitivity, specificity, and likelihood predictive ratio of airway fluoroscopy compared with FB in children suspected of having an airway abnormality.

Methods

Airway fluoroscopic examination was undertaken within 2‐weeks of a FB in children aged <18‐years and reported by a pediatric radiologist blinded to FB data. Fluoroscopic and FB methods and diagnostic criteria were standardized and defined a‐priori. Tracheomalacia diagnosed by FB were independently scored (mild, moderate, severe) by 2 pulmonologists in a blinded manner.

Results

In 22 children (median age 33 months, range 1–187) evaluated for airway abnormality, tracheomalacia was found in 21 children at bronchoscopy. Of these, fluoroscopy detected tracheomalacia in five children. Airway fluoroscopy was poorly sensitive (23.8%) but highly specific (100%), positive likelihood ratio was 8.6. However, in moderate‐severe tracheomalacia, the sensitivity improved to 57.1% but the specificity reduced (93.3%). The agreement between bronchoscopists for tracheomalacia severity was excellent, weighted kappa 0.74 (95% CI 0.77, 0.98).

Conclusion

Airway fluoroscopy cannot replace FB which remains the tool for definitively diagnosing airway malacia. However, in absence of other modalities for diagnosis fluoroscopy should be considered in the setting of persistent respiratory symptoms compatible with the clinical picture of tracheomalacia. Pediatr Pulmonol. 2012; 47:63–67. © 2010 Wiley Periodicals, Inc.
Defining pulmonary exacerbation in children with non‐cystic fibrosis bronchiectasis
Authors: Kapur Nitin , Masters Ian B. , Morris Peter S. , Galligan John , Ware Robert , Chang Anne B.
Published: August 2011

Rationale

Exacerbations in non‐cystic fibrosis (CF) bronchiectasis are associated with worsening lung functions and quality of life. A standardized definition of exacerbation could improve clinical care and research.

Objective

To formulate a clinically useful definition of pulmonary exacerbation for pediatric non‐CF bronchiectasis.

Methods

A cohort of 69 children with non‐CF bronchiectasis was prospectively followed for 900 child‐months. The changes in clinical, systemic, and lung function parameters from 81 exacerbations were statistically evaluated using conditional logistic regression, receiver operating characteristic, sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) to formulate a definition of a pulmonary exacerbation. Formation of major and minor criteria was statistically based and models were developed.

Measurements and Main Results

Wet cough and cough severity (score ≥2) over 72‐hr were the best predictors of an exacerbation with area under the curve (AUC) of 0.85 (95% CI 0.79–0.92) and 0.84 (95% CI 0.77–0.91), respectively. Sputum color, chest pain, dyspnea, hemoptysis, and chest signs were significant though minor criteria. Inclusion of serum C‐reactive protein, amyloid‐A, and IL6 to the definition improved its specificity and PPV. Our final combined model consisted of one major with one investigatory criterion (PPV 91%, NPV 72%); two major criteria (PPV 79%, NPV 91%); or one major and two minor criteria (PPV 79%, NPV 94%).

Conclusions

Pulmonary exacerbation in children with non‐CF bronchiectasis can be validly predicted using a standardized assessment of clinical features, with additional systemic markers improving predictive values. This definition potentially facilitates earlier detection (leading to appropriate management) of exacerbations. Pediatr Pulmonol. 2012; 47:68–75. © 2010 Wiley Periodicals, Inc.
Initial Pseudomonas aeruginosa treatment failure is associated with exacerbations in cystic fibrosis
Authors: Mayer‐Hamblett Nicole , Kronmal Richard A. , Gibson Ronald L. , Rosenfeld Margaret , Retsch‐Bogart George , Treggiari Miriam M. , Burns Jane L. , Khan Umer , Ramsey Bonnie W. ,   for the EPIC Investigators
Published: August 2011

Rationale

The risk of pulmonary exacerbation following Pseudomonas aeruginosa (Pa) acquisition in children with cystic fibrosis (CF) is unknown.

Objectives

To determine if failure of antibiotic therapy to eradicate Pa and frequency of Pa recurrence are associated with increased exacerbation risk.

Methods

The cohort included 282 children with CF who participated in the EPIC trial ages 1–12 with newly acquired Pa, defined as either a first lifetime Pa positive respiratory culture or positive after two years of negative cultures (past isolation of Pa but >2 years prior to the trial). All received antibiotics to promote initial eradication followed by 15 months of intermittent maintenance antibiotics. Quarterly cultures were used to define initial eradication success and subsequent number of Pa recurrences. A standardized symptom‐based definition of exacerbation was utilized. Cox proportional hazards models were used to estimate exacerbation risk.

Results

Failure to initially eradicate Pa was associated with exacerbation risk (hazard ratio [HR]: 2.49, 95% confidence interval [CI] 1.26, 4.93). In 245/282 with successful initial eradication during the trial, past isolation of Pa >2 years before the trial was the most significant predictor of exacerbation (HR 1.62, 95% CI 1.12, 2.35). In 37/282 who failed initial eradication, persistent Pa during the maintenance phase (1 or more Pa recurrences after failure to initially eradicate) added even greater exacerbation risk (HR 4.13, 95% CI 1.28, 13.32).

Conclusions

Children with CF who fail to eradicate after initial antibiotic treatment are at higher risk of subsequent exacerbation, suggesting clinical benefit to successful early eradication of Pa infection. Pediatr Pulmonol. 2012; 47:125–134. © 2011 Wiley Periodicals, Inc.
Variable human phenotype associated with novel deletions of the PHOX2B gene
Authors: Jennings Lawrence J. , Yu Min , Rand Casey M. , Kravis Nicole , Berry‐Kravis Elizabeth M. , Patwari Pallavi P. , Weese‐Mayer Debra E.
Published: August 2011

Background

Clinical testing for PHOX2B mutations is widely used for patients with any symptoms suggestive of hypoventilation (with/without anatomic/physiologic autonomic dysregulation), though not necessarily with the congenital central hypoventilation syndrome (CCHS) phenotype. Consequently, a multitude of referrals for clinical PHOX2B testing (fragment analysis of the 20 polyalanine repeat region and/or sequencing of entire coding region) have no identifiable mutation. Whole gene deletions/duplications have recently been identified as a common disease‐causing mechanism, but have not been reported in a clinical population referred for PHOX2B testing. The objective of this study was to determine if PHOX2B exon or whole gene deletion/duplication would be identified in a subset of patients referred for PHOX2B testing.

Hypothesis

We hypothesized that PHOX2B exon or whole gene deletion or duplication would be identified in a subset of cases who were referred for genetic testing but not found to have a PHOX2B mutation with currently available clinical PHOX2B testing.

Methods

Genomic DNA samples from patients that tested negative for PHOX2B mutations using fragment analysis and/or sequencing, and control samples, were screened for PHOX2B exon deletions/duplications by multiplex ligation‐dependent probe amplification with confirmation by array comparative genomic hybridization.

Results

Deletions of/in PHOX2B were identified in 4/250 patients and 0/261 controls. The deletions ranged from 6,216 base pairs (involving only PHOX2B exon 3) to 2.6 megabases (involving all of PHOX2B and 12 other genes). The case with PHOX2B partial exon 3 deletion had a CCHS‐compatible phenotype (hypoventilation, Hirschsprung disease). Phenotypes for the other three cases, all PHOX2B whole‐gene deletions, were varied including: (1) apparent life threatening event, (2) full CCHS necessitating artificial ventilation with ganglioneuroblastoma, and (3) hypoventilation during sleep. Family studies of two of the four probands showed these deletions to be maternally inherited; the mothers also had phenotypic findings of autonomic dysfunction.

Conclusions

PHOX2B exon or whole gene deletion should be considered as another mechanism of disease which may include CCHS, Hirschsprung disease, and/or tumors of neural crest origin, although the genotype–phenotype relationship requires further clarification. Pediatr Pulmonol. 2012; 47:153–161. © 2011 Wiley Periodicals, Inc.
Structural classification and properties of ketoacyl synthases
Authors: Chen Yingfei , Kelly Erin E. , Masluk Ryan P. , Nelson Charles L. , Cantu David C. , Reilly Peter J.
Published: August 2011

Ketoacyl synthases (KSs) catalyze condensing reactions combining acyl‐CoA or acyl‐acyl carrier protein (acyl‐ACP) with malonyl‐CoA to form 3‐ketoacyl‐CoA or with malonyl‐ACP to form 3‐ketoacyl‐ACP. In each case, the resulting acyl chain is two carbon atoms longer than before, and CO2and either CoA or ACP are formed. KSs also join other activated molecules in the polyketide synthesis cycle. Our classification of KSs by their primary and tertiary structures instead of by their substrates and the reactions that they catalyze enhances insights into this enzyme group. KSs fall into five families separated by their characteristic primary structures, each having members with the same catalytic residues, mechanisms, and tertiary structures. KS1 members, overwhelmingly named 3‐ketoacyl‐ACP synthase III or its variants, are produced predominantly by bacteria. Members of KS2 are mainly produced by plants, and they are usually long‐chain fatty acid elongases/condensing enzymes and 3‐ketoacyl‐CoA synthases. KS3, a very large family, is composed of bacterial and eukaryotic 3‐ketoacyl‐ACP synthases I and II, often found in multidomain fatty acid and polyketide synthases. Most of the chalcone synthases, stilbene synthases, and naringenin‐chalcone synthases in KS4 are from eukaryota. KS5 members are all from eukaryota, most are produced by animals, and they are mainly fatty acid elongases. All families except KS3 are split into subfamilies whose members have statistically significant differences in their primary structures. KS1 through KS4 appear to be part of the same clan. KS sequences, tertiary structures, and family classifications are available on the continuously updated ThYme (Thioester‐active enzYme) database.
Fabrication of adherent porous diamond films on sintered WC‐13 wt.%Co substrates by bias enhanced hot filament chemical vapour deposition
Authors: Wei Q. , Ashfold M. N. R. , Yu Z. M. , Ma L.
Published: August 2011

Porous diamond (PD) films have been grown on sintered WC‐13 wt.%Co substrates by bias enhanced hot filament (HF) chemical vapour deposition (CVD) methods and characterized by scanning electron microscopy (SEM), laser Raman spectroscopy and X‐ray diffraction (XRD). The PD films show excellent adhesion under Rockwell indentation testing. Factors encouraging the growth of diamond film with high porosity are discussed.

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Effect of argon addition on the growth of thick single crystal diamond by high‐power plasma CVD
Authors: Tallaire Alexandre , Rond Catherine , Bénédic Fabien , Brinza Ovidiu , Achard Jocelyn , Silva François , Gicquel Alix
Published: August 2011

Diamond films were synthesized with up to 50% argon in the gas phase using high power plasma‐assisted chemical vapour deposition (PACVD). This resulted in a strong increase of the deposition rates. Polycrystalline diamond (PCD) films grown with Ar have shown a higher incorporation of sp2 phases but with no dramatic change in crystal morphologies. Thick single crystal diamond films did not show any obvious change in crystal quality though. By using optical emission spectroscopy (OES) and plasma simulation, it was found that the gas temperature is increased by the addition of argon by at least 500 K. This in turn promotes dissociation of H2 into H‐atom as would be obtained from an increase of the plasma power density. High‐power PACVD with argon addition is thus an efficient technique for the fast growth of thick single crystal films without the cost and additional problems related to an increase of the injected microwave power.
On the quantum efficiency of InGaN light emitting diodes: Effects of active layer design, electron cooler, and electron blocking layer
Authors: Li X. , Zhang F. , Okur S. , Avrutin V. , Liu S. J. , Özgür Ü. , Morkoç H. , Hong S. M. , Yen S. H. , Hsu T. S. , Matulionis A.
Published: August 2011

Efficiency and efficiency retention in InGaN LEDs has recently received considerable attention. In this realm, we investigated internal quantum efficiency (IQE) and relative external quantum efficiency (EQE) of c‐plane InGaN LEDs designed for emission at ∼420 nm from the active region which contains multiple quantum wells (MQWs) of different barrier height (either In0.01Ga0.99N or In0.06Ga0.94N barriers) and thickness (3 and 12 nm) as well as a 9‐nm double heterostructure (DH). Pulsed electroluminescence (EL) and laser excitation power‐dependent measurements indicated that both the relative EQE and the IQE were enhanced due to the incorporated two‐layer InGaN stair‐case electron injector (SEI) with indium mole fraction steps of 4 and 8% as compared to the conventional AlGaN electron blocking layer (EBL). Furthermore, the lowered In0.06Ga0.94N interwell barriers (LB) instead of the traditional In0.01Ga0.99N barriers improved the EQE and the IQE of MQW LEDs. Specifically, the MQW LEDs with the 6‐period 2‐nm In0.2Ga0.8N quantum well and 3‐nm In0.06Ga0.94N barrier structure showed 6% higher IQE at an injected carrier density of 6 × 1018 cm−3 and 35% higher EQE as compared to that of the same structure with a higher In0.01Ga0.99N barrier. The DH LEDs showed 30% higher EQEs compared to MQW LEDs, albeit at a relatively higher injection current density of 150 A/cm2. The relatively low EQE in the DH LEDs at low injection levels is attributed to spatial separation of electrons and holes due to confinement in the interfacial triangular well and thus the associated decrease in radiative efficiency and possible increase in nonradiative recombination due to degradation of material quality with increasing InGaN layer thickness.
Map‐aided localization in sparse global positioning system environments using vision and particle filtering
Authors: Miller Isaac , Campbell Mark , Huttenlocher Dan
Published: August 2011

A map‐aided localization approach using vision, inertial sensors when available, and a particle filter is proposed and empirically evaluated. The approach, termed PosteriorPose, uses a Bayesian particle filter to augment global positioning system (GPS) and inertial navigation solutions with vision‐based measurements of nearby lanes and stop lines referenced against a known map of environmental features. These map‐relative measurements are shown to improve the quality of the navigation solution when GPS is available, and they are shown to keep the navigation solution converged in extended GPS blackouts. Measurements are incorporated with careful hypothesis testing and error modeling to account for non‐Gaussian and multimodal errors committed by GPS and vision‐based detection algorithms. Using a set of data collected with Cornell's autonomous car, including a measure of truth via a high‐precision differential corrections service, an experimental investigation of important design elements of the PosteriorPose estimator is conducted. The algorithm is shown to statistically outperform a tightly coupled GPS/inertial navigation solution both in full GPS coverage and in extended GPS blackouts. Statistical performance is also studied as a function of road type, filter likelihood models, bias models, and filter integrity tests. © 2011 Wiley Periodicals, Inc.
RANGE–Robust autonomous navigation in GPS‐denied environments
Authors: Bachrach Abraham , Prentice Samuel , He Ruijie , Roy Nicholas
Published: August 2011

This paper addresses the problem of autonomous navigation of a micro air vehicle (MAV) in GPS‐denied environments. We present experimental validation and analysis for our system that enables a quadrotor helicopter, equipped with a laser range finder sensor, to autonomously explore and map unstructured and unknown environments. The key challenge for enabling GPS‐denied flight of a MAV is that the system must be able to estimate its position and velocity by sensing unknown environmental structure with sufficient accuracy and low enough latency to stably control the vehicle. Our solution overcomes this challenge in the face of MAV payload limitations imposed on sensing, computational, and communication resources. We first analyze the requirements to achieve fully autonomous quadrotor helicopter flight in GPS‐denied areas, highlighting the differences between ground and air robots that make it difficult to use algorithms developed for ground robots. We report on experiments that validate our solutions to key challenges, namely a multilevel sensing and control hierarchy that incorporates a high‐speed laser scan‐matching algorithm, data fusion filter, high‐level simultaneous localization and mapping, and a goal‐directed exploration module. These experiments illustrate the quadrotor helicopter's ability to accurately and autonomously navigate in a number of large‐scale unknown environments, both indoors and in the urban canyon. The system was further validated in the field by our winning entry in the 2009 International Aerial Robotics Competition, which required the quadrotor to autonomously enter a hazardous unknown environment through a window, explore the indoor structure without GPS, and search for a visual target. © 2011 Wiley Periodicals, Inc.
Aerial remote sensing in agriculture: A practical approach to area coverage and path planning for fleets of mini aerial robots
Authors: Barrientos Antonio , Colorado Julian , Cerro Jaime del , Martinez Alexander , Rossi Claudio , Sanz David , Valente João
Published: August 2011

In this paper, a system that allows applying precision agriculture techniques is described. The application is based on the deployment of a team of unmanned aerial vehicles that are able to take georeferenced pictures in order to create a full map by applying mosaicking procedures for postprocessing. The main contribution of this work is practical experimentation with an integrated tool. Contributions in different fields are also reported. Among them is a new one‐phase automatic task partitioning manager, which is based on negotiation among the aerial vehicles, considering their state and capabilities. Once the individual tasks are assigned, an optimal path planning algorithm is in charge of determining the best path for each vehicle to follow. Also, a robust flight control based on the use of a control law that improves the maneuverability of the quadrotors has been designed. A set of field tests was performed in order to analyze all the capabilities of the system, from task negotiations to final performance. These experiments also allowed testing control robustness under different weather conditions. © 2011 Wiley Periodicals, Inc.
AUTOMATIC DELINEATION OF FUNCTIONAL RIVER REACH BOUNDARIES FOR RIVER RESEARCH AND APPLICATIONS
Authors: Parker C. , Clifford N. J. , Thorne C. R.
Published: August 2011

The river reach is a pervasive term within contemporary river research and applications. Yet, despite its prevalence, there is a notable lack of consistency in its definition. This paper identifies the presence of two broad types of reach definition within the academic literature, operational and functional, and argues that a functional definition is more suitable for applications within river research and management. A range of sequence zonation algorithms that were originally derived for geological well‐log analysis were compared for their ability to automatically identify functional reach boundaries. An analysis of variance‐based global boundary hunting algorithm was identified as the most suitable. To demonstrate the potential practical applications of automatic reach delineation methods, two case studies where functional reach boundaries have been identified were described: first, in a sequence of predicted sediment transport capacities for use in a reach‐based sediment transport model; and second, in a sequence of RHS Habitat Quality Assessment scores for identification of lengths of channel in need of habitat restoration efforts. Finally, the paper discusses how this type of functional reach identification procedure might be applied in other areas of river research and applications and how a multivariate version of a statistical zonation algorithm might prove useful in facilitating integrated catchment management by identifying reach boundaries common across all variables of interest in the system. Copyright © 2011 John Wiley & Sons, Ltd.
Surface roughness analysis of hardened steel after high‐speed milling
Authors: Twardowski Paweł , Wojciechowski Szymon , Wieczorowski Michał , Mathia Thomas
Published: August 2011

The work refers to analysis of various factors affecting surface roughness after end milling of hardened steel in high‐speed milling (HSM) conditions. Investigations of milling parameters (cutting speed vc, axial depth of cut ap) and the process dynamics that influence machined surface roughness were presented, and a surface roughness model, including cutter displacements, was elaborated. The work also involved analysis of surface profile charts from the point of view of vibrations and cutting force components.

The research showed that theoretic surface roughness resulting from the kinematic–geometric projection of cutting edge in the workpiece is significantly different from the reality. The dominant factor in the research was not feed per tooth fz (according to the theoretical model) but dynamical phenomena and feed per revolution f. SCANNING 33: 386–395, 2011. © 2011 Wiley Periodicals, Inc.