bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ethylene polymerization and ethylene/hexene copolymerization with vanadium(III) catalysts bearing heteroatom‐containing salicylaldiminato ligands
Authors: Wu Ji‐Qian , Pan Li , Liu San‐Rong , He Li‐Peng , Li Yue‐Sheng 
Published: June 2009

AbstractA series of novel vanadium(III) complexes bearing heteroatom‐containing group‐substituted salicylaldiminato ligands [RNCH(ArO)]VCl2(THF)2 (Ar = C6H4, R = C3H2NS, 2a; C7H4NS, 2c; C7H5N2, 2d; Ar = C6H2tBu2 (2,4), R = C3H2NS, 2b) have been synthesized and characterized. Structure of complex 2c was further confirmed by X‐ray crystallographic analysis. The complexes were investigated as the catalysts for ethylene polymerization in the presence of Et2AlCl. Complexes 2a–d exhibited high catalytic activities (up to 22.8 kg polyethylene/mmolV h bar), and affording polymer with unimodal molecular weight distributions at 25–70 °C in the first 5‐min polymerization, whereas produced bimodal molecular weight distribution polymers at 70 °C when polymerization time prolonged to 30 min. The catalyst structure plays an important role in controlling the molecular weight and molecular weight distribution of the resultant polymers produced in 30 min polymerization. In addition, ethylene/hexene copolymerizations with catalysts 2a–d were also explored in the presence of Et2AlCl, which leads to the high molecular weight and unimodal distributions copolymers with high comonomer incorporation. Catalytic activity, comonomer incorporation, and polymer molecular weight can be controlled over a wide range by the variation of catalyst structure and the reaction parameters, such as comonomer feed concentration, polymerization time, and polymerization reaction temperature. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3573–3582, 2009
The potential use of spirometry during methacholine challenge test in young children with respiratory symptoms
Authors: Vilozni Daphna , Livnat Galit , Dabbah Husein , Elias Nael , Hakim Fahed , Bentur Lea 
Published: June 2009

AbstractBackgroundThe concentration of methacholine that causes a fall of 20% from baseline forced expiratory volume in the first second (PC20‐FEV1) in the methacholine challenge test (MCT) is not usually considered a diagnostic tool in preschool children since PC20‐FEV1 may not be achievable <6 years of age.AimTo assess the usefulness of various spirometry indices obtained during MCT in a large group of 3‐ to 6‐year‐old children with respect to their clinical diagnosis.MethodsStandardized MCT (inhaled triple‐concentration increments [0.057–13.925 mg] of methacholine solution) was performed by 84 children previously diagnosed with asthma (asthmatics) and 48 with prolonged cough (coughers). Spirometry was determined at baseline and between inhalations; PC20‐FEV1 and PC25‐FEV0.5 were calculated.ResultsPC20‐FEV1 values were significantly less in the asthmatics than in the coughers (mean ± SD was 3.21 ± 4.32 vs. 22.35 ± 3.66 ml/mg). Similarly, PC25‐FEV0.5 was 1.48 ± 3.08 in the asthmatics and 9.45 ± 12.59 mg/ml/Mch in the coughers, P < 0.0001. A cut‐off at 4.0 mg/ml for PC20‐FEV1 had 77.4% sensitivity and 75.0% specificity, a cut‐off at 2.2 mg/ml for PC25‐FEV0.5 had 73.8% sensitivity and 72.9% specificity, for clinical diagnosis of asthma. PC25‐FEV0.5 also showed a correlation with age.ConclusionsOur findings suggest that MCT can be performed in preschool children with various respiratory symptoms. PC25‐FEV0.5 may be a better end‐point parameter. Children with a clinical diagnosis of asthma respond to a lower MCT concentration than children with cough. Further studies are needed to determine airway responsiveness in healthy young children and to further assess the contribution of MCT to the clinical diagnosis in this age group. Pediatr Pulmonol. 2009; 44:720–727. © 2009 Wiley‐Liss, Inc.
Mannitol and exercise challenge tests in asthmatic children
Authors: Kersten Elin T.G. , Driessen Jean M.M. , van der Berg Julianne D. , Thio Bernard J. 
Published: June 2009

AbstractBackgroundBronchial hyperresponsiveness (BHR), a characteristic feature of asthma, can be assessed through standardized bronchial provocation tests (BPT). Exercise as a BPT is used in diagnosing and monitoring exercise induced bronchoconstriction (EIB). Recently a novel osmotic BPT has been developed, using dry powder mannitol. The aim of this study was to investigate the clinical utility of the mannitol challenge to identify asthmatic children with EIB.Materials and MethodsThirty‐three clinically stable children, aged 9–18 years, with a history of EIB, performed both mannitol and exercise provocation challenges. Data were composed of a cross tabulation comparing the reaction on exercise provocation challenge to mannitol challenge. Correlations between post‐exercise fall in FEV1 and response–dose ratio (RDR) and PD15 of mannitol were calculated.ResultsTwenty‐five children completed both tests. Pearson's correlation between log‐transformed RDR for mannitol and post‐exercise fall in FEV1 was rp = 0.666 (P < 0.001). There was no significant relationship between the log PD15 of mannitol and post‐exercise fall in FEV1. Children on long acting bronchodilator agents (LABA) were significantly (P < 0.05) more likely to have a positive response on the mannitol challenge. Positive and negative predictive values of the mannitol challenge for EIB were 69% and 91%.ConclusionMannitol challenge appears to be a suitable alternative for an exercise provocation test to assess EIB in asthmatic children. Given the negative predictive value of 91%, it is especially useful to exclude EIB. Pediatr Pulmonol. 2009; 44:655–661. © 2009 Wiley‐Liss, Inc.
Decreased risk for atopic disorder associated with highly hyperreactive tuberculin skin test reaction in children and adolescents
Authors: Marija Maćešić , Mirjana Turkalj , Žaneta Jelčić , Slavica Dodig , Branka Kristić‐Kirin , Boro Nogalo , Davor Plavec 
Published: June 2009

AbstractBackgroundIt is speculated that the exposure to Mycobacterium tuberculosis, either by infection or by Bacillus Calmette‐Guérin vaccination, may inhibit the onset of atopy by the modification of immune profiles leading to a shift of TH1/TH2 balance to the TH1 side.ObjectiveOne hundred eighty‐six patients hyperreactive at tuberculin skin test (TST) were examined in order to investigate the prevalence of atopic disorder, particularly referring to the association between the size of the TST induration and the prevalence of sensitization and manifest atopic disorder.MethodsThe study consisted of a family history record, patients' medical history assessment and clinical examination, skin prick test (SPT), serum total and allergen‐specific IgE (sIgE) measurement and eosinophil count.ResultsAtopic disorder was present in 49 (26.3%) patients tested. No significant difference between the groups based on the TST induration size (15–24 mm vs. ≥25 mm) was found for gender distribution, family atopy history, total IgE measurement, eosinophil count, positive SPT, and the presence of sIgE. A significant difference was found for the age median (14.0 years vs. 13.0 years), childhood atopy record, and manifest atopic disorder. No association between the size of the TST induration and the incidence of allergic sensitization was demonstrated. However, a significant inverse association between the size of the TST induration and manifest atopic disorder was demonstrated.ConclusionIn patients highly hyperreactive at TST, the size of the induration is inversely associated with manifest atopic disorder. Pediatr Pulmonol. 2009; 44:701–705. © 2009 Wiley‐Liss, Inc.
High flow nasal cannula therapy as respiratory support in the preterm infant
Authors: Dani Carlo , Pratesi Simone , Migliori Claudio , Bertini Giovanna 
Published: June 2009

AbstractWe reviewed the literature on the effects of high flow nasal cannula (HFNC) and heated, humidified, high‐flow, nasal cannula (HHHFNC) treatment in preterm infants. We found nine studies, but only two were randomized controlled trials. These studies show that: HFNC application is associated to the delivery of continuous distending pressure (CDP) in patients with closed mouth, whose value is proportional to the delivered flow only in smaller infants; the CDP delivered by HFNC is unpredictable and present large inter‐patient and intra‐patient variability; the use of recently available HHHFNC devices is effective in minimizing nasal mucosa injuries compared to traditional HFNC; the effectiveness of HHHFNC versus NCPAP for the treatment of apnoea of prematurity, respiratory distress syndrome, and the prevention of extubation failure, has been poor investigated and firm conclusions cannot be drawn on this matter. In conclusion, on the basis of published data, the routinary application of HFNC should be limited to patients requiring oxygen‐therapy, HHHFNC devices should be preferred to HFNC, but their employment as an alternative to NCPAP should wait for the conclusion of randomized controlled trials. Pediatr Pulmonol. 2009; 44:629–634. © 2009 Wiley‐Liss, Inc.
Trace Detection of Explosives Vapours by Molecularly Imprinted Polymers for Security Measures
Authors: Bunte Gudrun , Heil Moritz , Röseling Dirk , Hürttlen Jürgen , Pontius Heike , Krause Horst 
Published: June 2009

AbstractIn view of the recent terror acts for example against aviation or underground transportation systems, it is obvious that the detection techniques used today for explosives are inadequate and have to be improved. In concern with national security there is need for inexpensive, rapid, highly sensitive and selective sensors. In this respect, mass‐sensitive devices coated with substance specific molecularly imprinted polymers (MIPs) look promising to achieve low‐cost detection devices capable of detecting gaseous explosives traces fast, sensitively and reliably. Preliminary results and possible concepts for MIP‐based low‐cost sensors are presented in this paper.
A Look Behind Electrochemical Detection of Explosives
Authors: Rabenecker Peter , Pinkwart Karsten 
Published: June 2009

AbstractFew years ago, the Fraunhofer Institute for Chemical Technology started researching the detection of the explosive TNT (2,4,6‐trinitrotoluene) in contaminated soil. This research resulted in a European patent and a sensor prototype. After successful transfer of the developed detection technology from the solid to the gaseous phase, nearly 20 additional explosives were researched. Most of these explosives were nitroaromatic compounds, but in the last few years some work has also been done with peroxide explosives as a response to terrorist threats. The current article shows the good ability of electrochemical sensors to the trace detection or discrimination of explosives.
Technology of Foamed Propellants
Authors: Böhnlein‐Mauß Jutta , Kröber Hartmut 
Published: June 2009

AbstractFoamed propellants are based on crystalline explosives bonded in energetic reaction polymers. Due to their porous structures they are distinguished by high burning rates. Energy content and material characteristics can be varied by using different energetic fillers, energetic polymers and porous structures. Foamed charges can be produced easily by the reaction injection moulding process. For the manufacturing of foamed propellants a semi‐continuous remote controlled production plant in pilot scale was set up and a modified reaction injection moulding process was applied.
Blast Load Diagnostic
Authors: Held Manfred 
Published: June 2009

AbstractDamage is mostly caused by the impulse transferred to the target. Therefore, the impulsive load measurements are summarized, which were mostly performed with simple and inexpensive test arrangements. This was possible, especially in the near field, where blast and blast fragment loads were causing damage to the soft as well as harder target structures. For more details, the used arrangements and results can be found in the reference list.
US regional income change and migration: 1995–2004
Authors: Shumway J. Matthew , Otterstrom Samuel 
Published: June 2009

AbstractOne of the most important concepts found in the migration literature is that it is a selective process, both in terms of who migrates and in the migrants' individual movement trajectories. The selectivity of migration means that the population structure at both origin and destination will change over time through migration, thus influencing the socio‐economic fabric of both sending and receiving regions. In this study we are primarily interested in the selectivity of migration relative to income and how migration affects the distribution of income across metropolitan areas in the U.S. We first cluster metropolitan areas by housing costs and then examine the flow of income migration relative to these costs using IRS county‐to‐county migration data for the years 1994/95 through 2003/04. Both total aggregate and per capita incomes by housing market clusters show some significant changes over the time frame used in this paper with moderate priced housing markets and non‐metropolitan areas the biggest gainers in aggregate income and some high priced housing markets and (once again) nonmetropolitan areas the biggest gainers in per capita income. Copyright © 2009 John Wiley & Sons, Ltd.
Metastability in the resistance of polycrystalline La0.8Li0.2MnO3
Authors: Knott J. C. , Lewis R. A. 
Published: June 2009

AbstractBulk polycrystalline La0.8Li0.2MnO3 is found to switch between a low‐resistance state and a high‐resistance state on thermal cycling. The low‐temperature, high‐resistance state exhibits strong electroresistance whereas the high‐temperature, low‐resistance state does not. The change in resistance between the two distinct states is of two orders of magnitude. It is proposed that the observed metastability may serve as the basis for resistive thermal‐switching devices.magnified image(© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sample size considerations for Japanese patients in a multi‐regional trial based on MHLW guidance
Authors: Quan Hui , Zhao Peng‐Liang , Zhang Ji , Roessner Martin , Aizawa Kyo 
Published: June 2009

AbstractSince the publication of the International Conference on Harmonization E5 guideline, new drug approvals in Japan based on the bridging strategy have been increasing. To further streamline and expedite new drug development in Japan, the Ministry of Health, Labour and Welfare, the Japanese regulatory authority, recently issued the ‘Basic Principles on Global Clinical Trials' guidance to promote Japan's participation in multi‐regional trials. The guidance, in a Q&A format, provides two methods as examples for recommending the number of Japanese patients in a multi‐regional trial. Method 1 in the guidance is the focus of this paper. We derive formulas for the sample size calculations for normal, binary and survival endpoints. Computations and simulation results are provided to compare different approaches. Trial examples are used to illustrate the applications of the approaches. Copyright © 2009 John Wiley & Sons, Ltd.
A comparative method to evaluate and validate stochastic parametrizations
Authors: Hermanson Leon , Hoskins Brian , Palmer Tim 
Published: June 2009

AbstractThere is a growing interest in using stochastic parametrizations in numerical weather and climate prediction models. Previously, Palmer (2001) outlined the issues that give rise to the need for a stochastic parametrization and the forms such a parametrization could take. In this article a method is presented that uses a comparison between a standard‐resolution version and a high‐resolution version of the same model to gain information relevant for a stochastic parametrization in that model. A correction term that could be used in a stochastic parametrization is derived from the thermodynamic equations of both models. The origin of the components of this term is discussed. It is found that the component related to unresolved wave–wave interactions is important and can act to compensate for large parametrized tendencies. The correction term is not proportional to the parametrized tendency. Finally, it is explained how the correction term could be used to give information about the shape of the random distribution to be used in a stochastic parametrization. Copyright © 2009 Royal Meteorological Society
Path‐following algorithms and experiments for an unmanned surface vehicle
Authors: Bibuli Marco , Bruzzone Gabriele , Caccia Massimo , Lapierre Lionel 
Published: June 2009

AbstractThis paper addresses the problem of path following in two‐dimensional space for underactuated unmanned surface vehicles (USVs), defining a set of guidance laws at the kinematic level. The proposed nonlinear Lyapunov‐based control law yields convergence of the path‐following error coordinates to zero. Furthermore, the introduction of a virtual controlled degree of freedom for the target to be followed on the path removes singularity behaviors present in other guidance algorithms proposed in the literature. Some heuristic approaches are then proposed to face the problem of speed of advance adaptation based on path curvature measurement and steering action prediction. Finally a set of experimental results of all the proposed guidance laws, carried out with the Charlie USV, demonstrates the feasibility of the proposed approach and the performance improvements, in terms of precision in following the reference path and transient reduction, obtained by introducing speed adaptation heuristics. © 2009 Wiley Periodicals, Inc.
Semiparametric ROC surfaces for continuous diagnostic tests based on two test measurements
Authors: Wan Shuwen , Zhang Biao 
Published: June 2009

AbstractWe propose a semiparametric method for estimating ROC surfaces for continuous diagnostic tests based on two test measurements. Such a three‐class diagnostic problem based on two test measurements arises naturally from some DNA amplification‐related diagnostic scenarios. Simulation results show that our proposed semiparametric ROC surface estimator is more efficient than the nonparametric counterpart and is quite comparable with the parametric counterpart when model assumption of the data is correctly specified for the parametric method. Moreover, when the parametric model assumption is not true, our proposed semiparametric method is superior to both nonparametric and parametric methods. Some discussions and a simulated example along with R programs for implementation of the proposed method are also provided. Copyright © 2009 John Wiley & Sons, Ltd.
A simple G‐computation algorithm to quantify the causal effect of a secondary illness on the progression of a chronic disease
Authors: van der Wal W. M. , Prins M. , Lumbreras B. , Geskus R. B. 
Published: June 2009

AbstractProgression of a chronic disease can lead to the development of secondary illnesses. An example is the development of active tuberculosis (TB) in HIV‐infected individuals. HIV disease progression, as indicated by declining CD4 + T‐cell count (CD4), increases both the risk of TB and the risk of AIDS‐related mortality. This means that CD4 is a time‐dependent confounder for the effect of TB on AIDS‐related mortality. Part of the effect of TB on AIDS‐related mortality may be indirect by causing a drop in CD4. Estimating the total causal effect of TB on AIDS‐related mortality using standard statistical techniques, conditioning on CD4 to adjust for confounding, then gives an underestimate of the true effect. Marginal structural models (MSMs) can be used to obtain an unbiased estimate. We describe an easily implemented algorithm that uses G‐computation to fit an MSM, as an alternative to inverse probability weighting (IPW). Our algorithm is simplified by utilizing individual baseline parameters that describe CD4 development. Simulation confirms that the algorithm can produce an unbiased estimate of the effect of a secondary illness, when a marker for primary disease progression is both a confounder and intermediary for the effect of the secondary illness. We used the algorithm to estimate the total causal effect of TB on AIDS‐related mortality in HIV‐infected individuals, and found a hazard ratio of 3.5 (95 per cent confidence interval 1.2–9.1). Copyright © 2009 John Wiley & Sons, Ltd.
Parent contribution and organizational control in international joint ventures
Authors: Chen Dong , Park Seung Ho , Newburry William 
Published: June 2009

AbstractOrganizational control scholars have recently noted how control use is not singular in organizations, but rather, different types of control are used to achieve different purposes. In international joint ventures (IJVs), we suggest that output, process, and social control are exercised by both foreign and local parent firms. We then hypothesize that a parent firm's usage of these three control types is influenced by its resource contributions. Using a sample of IJVs in China, we find that property‐based contribution is linked with output and process control, and knowledge‐based contribution is related to process and social control. The results also show differences in control practices between foreign and local parent firms. The findings provide important implications for the design and implementation of control systems in IJVs.
Parallel Preparation of Densely Packed Arrays of 150‐nm Gold‐Nanocrescent Resonators in Three Dimensions
Authors: Retsch Markus , Tamm Matthias , Bocchio Noelia , Horn Natalie , Förch Renate , Jonas Ulrich , Kreiter Maximilian 
Published: June 2009

AbstractMetallic nanostructures show interesting optical properties due to their plasmonic resonances, and when arranged in three‐dimensional (3D) arrays hold promise for optical metamaterials with negative refractive index. Towards this goal a simple, cheap, and parallel method to fabricate large‐area, ordered arrays of 150‐nm gold nanocrescents supporting plasmonic resonances in the near‐infrared spectral range is demonstrated. In this process hexagonally ordered monolayers of monodisperse colloids are prepared by a simple floating technique, and subsequently the individual particles are size‐reduced in a plasma process and used as a shadow mask with the initial lattice spacing. The resulting two‐dimensional array of plasmonic resonators is coated with a transparent silica layer, which serves as a support for a second layer prepared by the identical process. The mutual orientation of the nanostructures between the individual layers can be freely adjusted, which determines the polarization‐dependent absorption of the array and opens the possibility to introduce chirality in this type of 3D metamaterial. The iteration of this simple and efficient methodology yields 3D arrays with optical features as sharp as those of the individual nanocrescents, and shows strong potential for large‐scale production of high‐quality optical metamaterials.