bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single layer light‐emitting diodes from copolymers comprised of mesogen‐jacketed polymer containing oxadiazole units and PVK
Authors: Wang Ping , Chai Chunpeng , Wang Fuzhi , Chuai Yutao , Chen Xiaofang , Fan Xinghe , Zou Dechun , Zhou Qifeng 
Published: January 2008

AbstractA series of copolymers PCt‐co‐Poly(N‐vinylcarbazole) were synthesized through common radical polymerization, in which P‐Ct as a kind of mesogen‐jacketed liquid crystalline polymer was introduced, and the effects of copolymers composing variation on the optical properties of the polymers were studied. The structures and properties of the copolymers were characterized and evaluated by thermogravimetric (TGA), UV, photoluminescence (PL), cyclic voltammetry (CV), and electroluminescence (EL) analyses. All the polymers enjoy high thermal stability. PL peaks in the film show blue‐shift compared with in solutions and fluorescent quantum efficiency decreased with the N‐vinylcarbazole (nvk) content increasing, which supported the efficient energy transfer from nvk units to the oxadiazole units. CV revealed that, with the incorporation of nvk to the copolymer, these copolymers had high‐lying HOMO energy levels ranging from −5.94 to −6.09 eV. Single‐layer light‐emitting diodes (LEDs) with the configuration of ITO/PEDOT/PCt‐nvk/Mg:Ag/Ag were fabricated, which emit a blue light around 450 and 490 nm with a maximum luminance of 703 cd/m2. The device performance varies with the content of nvk and device configuration, with device configuration (b) and PCt‐nvk8 giving the best value of external quantum efficiency of 0.27%. We show here that by proper design copolymer structure and modification of device configuration can exhibit strong blue EL in higher external quantum efficiency. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1843–1851, 2008
Novel aliphatic poly(ester‐carbonate) with pendant allyl ester groups and its folic acid functionalization
Authors: Hu Xiuli , Chen Xuesi , Liu Shi , Shi Quan , Jing Xiabin 
Published: January 2008

AbstractA series of novel poly(ester‐carbonate)s bearing pendant allyl ester groups P(LA‐co‐MAC)s were prepared by ring‐opening copolymerization of L‐lactide (LA) and 5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxan‐2‐one (MAC) with diethyl zinc (ZnEt2) as initiator. NMR analysis investigated the microstructure of the copolymer. DSC results indicated that the copolymers displayed a single glass‐transition temperature (Tg), which was indicative of a random copolymer, and the Tg decreased with increasing carbonate content in the copolymer. Then NHS‐activated folic acid (FA) first reacted with 2‐aminoethanethiol to yield FA‐SH; grafting FA‐SH to P(LA‐co‐MAC) in the presence of TEA produced P(LA‐co‐MAC)/FA. The structure of P(LA‐co‐MAC)/FA and its precursor were confirmed by 1H NMR and XPS analysis. Cell experiments showed that FA‐grafted P(LA‐co‐MAC) had improved adhesion and proliferation behavior of vero cells on the polymer films. Therefore, the novel FA‐grafted block copolymer is expected to find application in drug delivery or tissue engineering. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1852–1861, 2008
Living star polymer formation (RAFT) studied via electrospray ionization mass spectrometry
Authors: Chaffey‐Millar Hugh , Hart‐Smith Gene , Barner‐Kowollik Christopher 
Published: January 2008

AbstractA mass spectrometry analysis has been performed on complex architecture polymeric material produced during reversible addition fragmentation chain transfer (RAFT) polymerizations yielding star polymers. Para‐acetoxystyrene (AcOSty) has been polymerized at 60 °C, using azobisisobutyronitrile (AIBN) as the thermally decomposing initiator, in the presence of the R‐group approach tetrafunctional RAFT agent (1,2,4,5‐tetrakis‐(2‐phenyl‐thioacetyl‐sulfanylmethyl)‐benzene). In addition to ideal star material, a variety of products unique to this mode of polymerization have been identified. These include star–star couples, stars terminated with initiator fragments, star–star couples terminated with initiator fragments and linear polymers, supporting the notion that these species are responsible for the structured molecular‐weight distributions measured for these systems when analyzed via gel permeation chromatography. The analysis begins with a study of AcOSty polymerizing (i) in the absence of any mediating agent and (ii) in the presence of a monofunctional RAFT agent, revealing the mode of termination of propagating poly(AcOSty) radicals as combination and that some ionization biases exist among variants of poly (AcOSty). The interpretation of the mass spectrometry data has been aided by a novel kinetic model of star polymerizations, allowing the rationalization of experimental observations with theoretical expectations. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1873–1892, 2008
The influence of variant PE‐b‐PEO segments on physical properties of LLDPE graft copolymers
Authors: Li Lili , Yin Jinghua , Costa Giovanna , Stagnaro Paola 
Published: January 2008

AbstractA method was adopted to fix a series of polymers of PE‐b‐PEO with different PEO/PE segments on the chains of LLDPE. Maleic anhydride (MA) reacting with hydroxyl group of PE‐b‐PEO (mPE‐b‐PEO) was used as the intermediate. The structures of intermediates and graft copolymers were approved by 1H NMR and FTIR. XPS analysis revealed a great amount of oxygen on the surface of grafted copolymers although the end group of PEO was fixed on the LLDPE chains through MA. Thermal properties of the graft copolymers as determined by differential scanning calorimetry (DSC) showed that PE segments in the grafted monomers could promote the heterogeneous nucleation of the polymer, increase Tc, and crystal growth rate. While the amorphous PEO segments which attached to the crystalline PE segments in LLDPE, impaired their ability to fit the crystal lattice, and depressed the crystallization of LLDPE backbones. In this study, it was also verified through the dynamic rheological data that increasing Mn of grafted monomers significantly increased the complex viscosity and enhanced the shear‐thinning behavior. Long‐branched chains formed by grafted monomers enhanced the complex moduli (G′ and G″) value and retarded relaxation rate. However, there were little influence on the rheological properties when increasing the amounts of PEO segments (or decreasing PE segments) of grafted monomers with similar molecular weight. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 506–515, 2008
Plasticization of amorphous perfluoropolymers
Authors: Lugert Elizabeth C. , Lodge Timothy P. , Bühlmann Philippe 
Published: January 2008

AbstractPoly(perfluoro‐4‐vinyloxy‐1‐butene), which is also known as Cytop, and poly[4,5‐difluoro‐2,2‐bis(trifluoromethyl)‐1,3‐dioxole]‐co‐poly(tetrafluoroethylene) copolymers with dioxole monomer contents of 65% or 87% (known as Teflon AF1600 and Teflon AF2400, respectively) were plasticized with four fluorous compounds. While plasticization of all polymers with perfluoroperhydrophenanthrene, perfluoro(1‐methyldecalin), a perfluorotetraether with three trifluoromethyl side groups and one hydrogen atom, and a linear perfluorooligoether with an average of 14.3 ether groups per molecule was successful, these four plasticizers affected the 12 blends very differently. A threshold of plasticization beyond which further increases in the plasticizer volume fraction did not further affect the glass transition temperature, Tg, was observed for some blends. Also, the limit of miscibility ranged from as low as 20% plasticizer content to complete miscibility at all volume fractions. The blends of Teflon AF2400 or Teflon AF1600 with high contents of the oligoether provided Tg values as low as −114 °C, lower than for any other fully miscible blend. The occurrence of two glass transitions in an intermediate range of plasticizer volume ratios for these two types of blends can be explained by distinct local environments rather than macroscopic phase separation, as anticipated by the Lodge‐McLeish model. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 516–525, 2008
Appetite stimulants use in cystic fibrosis
Authors: Nasr Samya Z. , Drury Donna 
Published: January 2008

AbstractCystic fibrosis (CF) is an autosomal recessive disease. It affects multiple body organs. The lungs and pancreas are the most affected which results in progressive lung damage and pancreatic insufficiency. Due to the disease process, CF patients require significantly higher caloric intake than recommended for other individuals. The nutritional goal for CF patients is to achieve normal growth and development and, once genetic potential is reached, to maintain good nutritional status throughout life. Evidence has shown that lung function is closely associated with nutritional status in CF and that nutritional status is an independent predictor of survival. Most CF patients are on a high calorie diet to help achieve normal growth and development and maintain good lung function. Inadequate caloric intake in CF can lead to malnutrition. Malnutrition in CF requires careful, multidisciplinary history taking, physical exam, and overall patient/family assessment. Only by determining the actual cause of the malnutrition can appropriate and safe therapies be used to treat it. Appetite stimulants, although efficacious in treating malnutrition in CF, should only be prescribed if decreased food intake secondary to inadequate appetite is the principal cause of the malnutrition and all other contributing factors have been assessed, ruled‐out or treated. In this review, we attempted to summarize the use of several appetite stimulants used in CF and other diseases to improve appetite and maximize caloric intake. Pediatr Pulmonol. 2008; 43:209–219. © 2008 Wiley‐Liss, Inc.
Premorbid factors and outcome associated with respiratory virus infections in a pediatric intensive care unit
Authors: Hon Kam Lun , Hung Erica , Tang Julian , Chow Chung Mo , Leung Ting Fan , Cheung Kam Lau , Ng Pak Cheung 
Published: January 2008

AbstractObjectivesThe purpose of this study was to report the clinical features and outcome of all children with a laboratory proven diagnosis of respiratory virus infection admitted to a university Pediatric Intensive Care Unit (PICU).MethodsRetrospective study between January 2003 and April 2007 was carried out in the PICU. Every child with a laboratory‐confirmed viral infection was included.Results54 viruses were identified in 49 children (27 M, 22 F) over a 52‐month period. The three respiratory virus species, respiratory syncytial virus (RSV) (n = 17), influenza (n = 13) and parainfluenza (n = 12), accounted for 86% of these 49 cases. PICU admissions due to influenza A (n = 10) were more common than influenza B (n = 3), whereas parainfluenza type 3 (n = 7) was the commonest subtype of parainfluenza infection. Comparing these three common viruses, the mean age of children admitted with RSV was lower than with influenza or parainfluenza (1.2 years vs. 5.6 years vs. 2.4 years, P = 0.003). Pre‐existing conditions such as prematurity and chronic lung disease were only present in children with RSV infection. These respiratory viruses caused both upper (croup) and lower respiratory tract diseases (bronchiolitis, pneumonia). Extrapulmonary presentations were less prevalent and included encephalitis, seizures, cardiac arrest, coexisting diabetes ketoacidosis and acute lymphoblastic leukemia. One patient with RSV and another with influenza A died during their PICU stay. Nearly half of these patients required ventilatory support or received systemic corticosteroids, and 88% received initial broad spectrum antibiotic coverage. Approximately one in five of them had nebulised adrenaline, airway endoscopies or bacterial co‐infections. Adenovirus was isolated in four patients and two (both with adenovirus type 3) died during the PICU stay.ConclusionsIn PICU, respiratory viral infections were associated with significant morbidity and life‐threatening conditions. Pediatr Pulmonol. 2008; 43:275–280. © 2008 Wiley‐Liss, Inc.
Prolonged, documented home‐monitoring of oxygenation in infants and children
Authors: Gélinas Jean‐François , Davis G. Michael , Arlegui Cheryl , Côté Aurore 
Published: January 2008

AbstractRationaleAlthough home cardiorespiratory monitors have been used for a few decades, they do not give information on oxygenation status during events. Pulse oximeters with low false‐alarm rates are now available but with no standards for alarm adjustment.ObjectiveTo determine, in a population of children monitored at home with a pulse oximeter, whether the chosen alarm levels could safely identify potentially significant events early on but also limit the number of alarms for non‐significant events.MethodsRetrospective cohort study of all children monitored at home with a pulse oximeter (n = 37) between 2002 and 2007. Clinical information and Hb‐O2 saturation (SpO2) recordings were reviewed. Audible alarm was set‐up when SpO2 reached 85% with a delay of 5 or 10 sec.ResultsA total of 24,127 hr of valid data were available for analysis. There were 13,228 events >4 sec of which 9177 (69%) were events lasting <10 sec. We determine that, with an audible alarm being triggered when SpO2 reached 85% with no delay or a delay of 5 or 10 sec, audible alarms would have occurred at a rate of 3.6, 0.9, and 0.2 alarm/night (median), respectively. Thirteen patients needed intervention following alarms. Ten patients were readmitted to the hospital on the basis of increased frequency of alarms confirmed as true events on the recordings, but in the absence of clinical deterioration.ConclusionThe monitor was able to alert parents as to potentially dangerous events while the alarm adjustment limited the number of alarms for non‐significant events. Pediatr Pulmonol. 2008; 43:288–296. © 2008 Wiley‐Liss, Inc.
Variability in measurements of micro lengths with a white light interferometer
Authors: Ferri Carlo , Brousseau Emmanuel 
Published: January 2008

AbstractThe effect of the discretionary set‐up parameters scan length and initial scanner position on the measurements of length performed with a white light interferometer microscope was investigated. In both analyses, two reference materials of nominal lengths 40 and 200 µm were considered. Random effects and mixed effects models were fitted to the data from two separate experiments. Punctual and interval estimates of variance components were provided. Copyright © 2008 John Wiley & Sons, Ltd.
Scanning Probe‐based Fabrication of 3D Nanostructures via Affinity Templates, Functional RNA, and Meniscus‐mediated Surface Remodeling
Authors: Chung Sung‐Wook , Presley Andrew D. , Elhadj Selim , Hok Saphon , Hah Sang Soo , Chernov Alex A. , Francis Matthew B. , Eaton Bruce E. , Feldheim Daniel L. , Deyoreo James J. 
Published: January 2008

AbstractDeveloping generic platforms to organize discrete molecular elements and nanostructures into deterministic patterns on surfaces is one of the central challenges in the field of nanotechnology. Here we review three applications of the atomic force microscope (AFM) that address this challenge. In the first, we use two‐step nanografting to create patterns of self‐assembled monolayers (SAMs) to drive the organization of virus particles that have been either genetically or chemically modified to bind to the SAMs. Virus‐SAM chemistries are described that provide irreversible and reversible binding, respectively. In the second, we use similar SAM patterns as affinity templates that have been designed to covalently bind oligonucleotides engineered to bind to the SAMs and selected for their ability to mediate the subsequent growth of metallic nanocrystals. In the final application, the liquid meniscus that condenses at the AFM tip‐substrate contact is used as a physical tool to both modulate the surface topography of a water soluble substrate and guide the hierarchical assembly of Au nanoparticles into nanowires. All three approaches can be generalized to meet the requirements of a wide variety of materials systems and thereby provide a potential route toward development of a generic platform for molecular and materials organization. SCANNING 30: 000–000, 2008. © 2008 Wiley Periodicals, Inc.
The feedback method of teaching macroeconomics: is it effective?
Authors: Wheat I. David 
Published: January 2008

AbstractThe conventional method of teaching macroeconomics to undergraduates relies on static graphs, an approach with documented pedagogical problems. In contrast, the feedback method uses causal loop diagrams and interactive computer simulation models. This paper describes the feedback method and four experiments that tested its effectiveness. Two experiments examined student preferences for methods of learning macroeconomics (e.g., using static graphs or a causal loop diagram), and a significant majority preferred the feedback method. In the third experiment, students showed more understanding of GDP when they had access to a stock‐and‐flow feedback diagram of the economy. In the final experiment, students using causal loop diagrams displayed more understanding of business cycle dynamics than those with access to a conventional aggregate supply‐and‐demand graph. Searching for feedback structure in the economy and using computer simulation to connect structure with behavior appears to be a promising method for learning macroeconomics. Copyright © 2007 John Wiley & Sons, Ltd.
Characterizations of bismuth telluride films from Mott‐Schottky plot and spectroscopic ellipsometry
Authors: Zimmer Alexandre , Stein Nicolas , Johann Luc , Terryn Herman , Boulanger Clotilde 
Published: January 2008

AbstractCapacitance measurement results (via the so‐called Mott‐Schottky plot) and Infrared spectroscopic ellipsometry (IRSE) analysis have been carried out in order to study semiconducting properties of electroplated thin films of bismuth telluride (Bi2Te3) without any electrical contact. Electrochemical impedance measurements at 10 kHz exhibited that films characterized n‐type semiconductors, depending upon potentials applied above and below the flat‐band potential. By IRSE study, the energy band gap Eg was found to be about 0.11 eV independent of the film composition and the electrical resistivity of about 30 µΩ.m. By combining IRSE and capacitance measurement results, dielectric constant ε and carrier concentration of the samples were calculated without any assumptions. Copyright © 2008 John Wiley & Sons, Ltd.
EIS studies of electrodeposition process of manganese and copper doped ZnO wires
Authors: Sima Marian , Enculescu Ionut , Sima Mariana , Vasile Eugen , Visan Teodor 
Published: January 2008

AbstractElectrodeposition of manganese‐ and copper‐doped ZnO wires into polycarbonate membranes, from an aqueous solution containing 0.05 mol dm−3 Zn(NO3)2 + 0.01 mol dm−3 Mn(NO3)2 + 0.0005 mol dm−3 Cu(NO3)2 + 0.0075 mol dm−3 lactic acid, pH = 4.7 was investigated using linear sweep voltammetry and electrochemical impedance spectroscopy (EIS). The equivalent electrical circuits for fitting experimental results were similar to those for characterization of metal/polymer coating systems. Impedance data and voltammetric curves showed that an increase of local pH due to reduction process of nitrate ions induces the co‐precipitations of metal ions in the proximity of electrode as oxides. Copyright © 2008 John Wiley & Sons, Ltd.
Placebo effect‐adjusted assessment of quality of life in placebo‐controlled clinical trials
Authors: Eickhoff Jens C. 
Published: January 2008

AbstractQuality of life (QoL) has become an accepted and widely used endpoint in clinical trials. The analytical tools used for QoL evaluations in clinical trials differ from those used for the more traditional endpoints, such as response to disease, overall survival or progression‐free survival. Since QoL assessments are generally performed on self‐administered questionnaires, QoL endpoints are more prone to a placebo effect than traditional clinical endpoints. The placebo effect is a well‐documented phenomenon in clinical trials, which has led to dramatic consequences on the clinical development of new therapeutic agents. In order to account for the placebo effect, a multivariate latent variable model is proposed, which allows for misclassification in the QoL item responses. The approach is flexible in the sense that it can be used for the analysis of a wide variety of multi‐dimensional QoL instruments. For statistical inference, maximum likelihood estimates and their standard errors are obtained using a Monte Carlo EM algorithm. The approach is illustrated with analysis of data from a cardiovascular phase III clinical trial. Copyright © 2008 John Wiley & Sons, Ltd.
A multi‐level two‐part random effects model, with application to an alcohol‐dependence study
Authors: Liu Lei , Ma Jennie Z. , Johnson Bankole A. 
Published: January 2008

AbstractTwo‐part random effects models (J. Am. Statist. Assoc. 2001;96:730–745;Statist. Methods Med. Res. 2002;11:341–355) have been applied to longitudinal studies for semi‐continuous outcomes, characterized by a large portion of zero values and continuous non‐zero (positive) values. Examples include repeated measures of daily drinking records, monthly medical costs, and annual claims of car insurance. However, the question of how to apply such models to multi‐level data settings remains. In this paper, we propose a novel multi‐level two‐part random effects model. Distinct random effects are used to characterize heterogeneity at different levels. Maximum likelihood estimation and inference are carried out through Gaussian quadrature technique, which can be implemented conveniently in freely available software—aML. The model is applied to the analysis of repeated measures of the daily drinking record in a randomized controlled trial of topiramate for alcohol‐dependence treatment. Copyright © 2008 John Wiley & Sons, Ltd.
n‐Dimensional effectiveness metric‐compensating reward scheme in performance‐based logistics contracts
Authors: Sols Alberto , Nowicki David , Verma Dinesh 
Published: January 2008

AbstractA paradigm shift is occurring in the relationship between suppliers and customers as the public sector continues to embrace the notion of Performance Based Logistics (PBL). There is now an increasing reliance on PBL concepts to define and monitor contractual relationships in both public and private industry. Successful PBL relationships are certainly faced with a number of challenges and difficulties. As uncovered by the work of Sols, Verma, and Nowicki [Eng Management J 19(2) (June 2007), 40– 50], the principle impediment to a successful PBL outcome is the proper formulation and mutual understanding, between supplier and customer, of the underlying financial reward/penalty model central to any PBL arrangement. The current state of the literature focuses on compensation structures based on only a single performance metric, which in most cases is insufficient to properly capture, reward, and penalize the supplier's performance. Instead, it is imperative to define and monitor multiple performance metrics to more accurately portray the performance the supplier is delivering in accordance to the customer's explicit expectations. This paper formulates an n‐dimensional performance‐based reward model for use in PBL contracts. Each dimension corresponds to a performance metric and the n‐dimensional reward model includes the notion of acceptable degree of variation in effectiveness (or, equivalently, a proportionality zone), of customer's acceptable compensation among metrics when there is overperformance for some and underperformance for others. An illustrative example is presented to show the applicability to PBL contractual relationships. © 2008 Wiley Periodicals, Inc. Syst Eng