bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of phosphinated bisphenol from acid‐fragmentation of 1,1,1‐tris(4‐hydroxyphenyl)ethane and its application in high‐performance cyanate esters
Authors: Lin Ching Hsuan , Lin Hung Tse , Tian Yu Wei , Dai Shenghong A. , Su Wen Chiung 
Published: September 2011

AbstractWe reveal a route for the preparation of phosphinated bisphenol, 1,1‐bis(4‐hydroxyphenyl)‐1‐(6‐oxido‐6H‐dibenz <c,e> <1,2> oxaphosphorin‐6‐yl)ethane (2), via a one‐pot reaction of 1,1,1‐tris(4‐hydroxyphenyl)ethane and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide (DOPO) in the catalysis of p‐toluenesulfonic acid. A two‐step reaction mechanism, acid‐fragmentation of 1,1,1‐tris(4‐hydroxyphenyl)ethane followed by nucleophilic addition of DOPO, is proposed for the synthesis. Based on (2), a dicyanate ester derivative, 1,1‐bis(4‐cyanatophenyl)‐1‐(6‐oxido‐6H‐dibenz <c,e> <1,2> oxaphosphorin‐6‐yl)ethane (3) was prepared and co‐cured with a commercially available dicyanate ester, the dicyanate ester of bisphenol A (BACY). Experimental data show that incorporating (3) into BACY enhances the flame retardancy and dielectric properties with little penalty to the thermal properties. A thermoset with Tg 274 °C, coefficient of thermal expansion (CTE) 49 ppm/°C, Dk 3.04 (1 GHz), Td (5%,) N2: 435 °C, air: 424 °C, and UL‐94 V‐0 rating can be achieved via this approach. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
Pi‐conjugated chain extenders for the synthesis of optoelectronic segmented polyurethanes
Authors: Harvey Christopher P. , Tovar John D. 
Published: September 2011

AbstractThe optical properties of mechanochromic materials change under mechanical stress. Segmented polyurethanes are elastomers composed of amorphous, saturated chain soft segments, and rigid pi‐conjugated hard domains. Within aggregates of hard domains pi–pi interactions may form and result in perturbation of the optoelectronic properties of the system. Disruption and restoration of these electronic interactions within the material may lead to observable mechanochromic response. A series of oligothiophene diols and diamines, as well as a naphthalene diimide diol, have been synthesized for incorporation into the hard domains of segmented polyurethanes and polyureas using long poly(tetramethylene oxide) chains as soft segments. The resulting polymers were evaluated to determine their extent of polymerization and their thermal stability. The optical properties of the materials were studied in solution and as thin films. Where possible the electrochemical properties of the polymers were also explored. The length of the soft segment chains in the segmented polyurethanes hindered electronic coupling of hard domains. Future work involving smaller, more solubilizing soft segments may allow for easier material characterization and mechanochromic response. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
TREN versus Me6‐TREN as ligands in SET‐LRP of methyl acrylate
Authors: Nguyen Nga H. , Levere Martin E. , Percec Virgil 
Published: September 2011

AbstractThe commercially available tris(2‐aminoethyl)amine (TREN) was used as ligand to mediate the single‐electron transfer‐living radical polymerization (SET‐LRP) of methyl acrylate in dimethyl sulfoxide initiated with the bifunctional initiator bis(2‐bromopropionyl)ethane and catalyzed by both nonactivated and activated Cu(0) wire. A comparative study between TREN and tris(2‐dimethylaminoethyl)amine (Me6‐TREN) ligand, that is more commonly used in SET‐LRP, demonstrated that TREN provided a slower polymerization but the chain‐ends functionality of the resulting bifunctional poly(methyl acrylate) was near quantitative and comparable to that obtained when Me6‐TREN was used as a ligand. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012.
Decoupling the effects of crystallinity and orientation on the shear piezoelectricity of polylactic acid
Authors: Lovell Conrad S. , Fitz‐Gerald James M. , Park Cheol 
Published: September 2011

AbstractShear piezoelectricity has been shown to be linearly proportional to the product of polymer crystallinity and orientation. However, investigations concerning the singular and cumulative effects of these parameters are incomplete since these studies relied exclusively on using orientation to alter crystallinity. In this research, polylactic acid (PLA) samples were fabricated by a dual drawing/annealing process to expand the investigation into the relationship between crystallinity, orientation, and shear piezoelectricity. The results of this study show for the first time that PLA shear piezoelectricity possesses a stronger relationship with the product of crystallinity and orientation than either of these parameters individually. However, this research also shows that processing of PLA for shear piezoelectric applications should focus only on achieving large degrees of orientation, which will inherently lead to increases in crystallinity as well. This approach will optimize PLA's shear sensing capabilities while avoiding certain detrimental effects, specifically embrittlement and a reversal of polymer chain orientation, which can occur during annealing. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1555–1562, 2011
Evolution of surfactant protein‐D levels in children with ventilator‐associated pneumonia
Authors: Said Ahmed S. , Abd‐ElAziz Manal M. , Farid Mohamed M. , Abd‐ElFattah Magid A. , Abdel‐Monim Mahmoud T. , Doctor Allan 
Published: September 2011

AbstractRationaleThe pathobiology of ventilator‐associated pneumonia (VAP) in children is poorly understood; investigation has been limited by lack of universally applied diagnostic criteria and reliable biomarkers for this condition.ObjectivesWe evaluated the clinical pulmonary infection score (CPIS) in diagnosing VAP and prospectively characterized the relationship between surfactant protein‐D (SP‐D) metabolism and VAP.MethodsChildren admitted to an Egyptian PICU requiring intubation were screened for the absence of primary pulmonary pathology. Thirty‐nine children underwent two evaluations: during the first 36 hr following intubation and after 4 days of mechanical ventilation. During both, bronchoalveolar lavage fluid (BALF) was obtained for culture and SP‐D assay. CPIS was computed during the second evaluation.ResultsOptimum performance of the CPIS against BALF culture occurred at a cutoff value of 6, (ROC AUC of 0.89 ± 0.05). Children who developed VAP had significantly higher SP‐D levels, both preceding (129.9 ± 33.5 ng/ml at the 1st BAL)—and following positive BALF culture (249.5 ± 51.2 ng/ml at the 2nd BAL), compared to children whose BALF remained sterile (62.6 ± 18.1 ng/ml and 64.9 ± 9.4 ng/ml; P < 0.001). This increase in SP‐D levels was most evident in children infected with Pseudomonas aeruginosa compared to children with Klebsiella pneumonia or S. aureus.ConclusionsThe CPIS performed well against BALF culture. We observed a bacterial species‐specific difference in SP‐D levels in children who developed VAP; this change preceded detection of infection by CPIS or BALF culture. Pediatr Pulmonol. 2012; 47:292–299. © 2011 Wiley Periodicals, Inc.
Clinical predictors of nasal continuous positive airway pressure requirement in acute bronchiolitis
Authors: Evans Jordan , Marlais Matko , Abrahamson Ed 
Published: September 2011

AbstractIntroductionThere is growing use of nasal continuous positive airway pressure ventilation (nCPAP) for infants with bronchiolitis, based on clinical assessment of severity. Despite this there have been no studies which identify clinical predictors for the requirement of nCPAP.ObjectiveTo identify clinical factors in infants with acute bronchiolitis in the emergency department (ED), which might predict a requirement for nCPAP following admission.Materials and MethodsRetrospective review of pediatric ED case notes was conducted on bronchiolitis admissions to one dedicated Paediatric ED over a 12‐month period. Potential predictors were identified through literature review. Data extraction of predictors was carried out and recorded for each case. Logistic regression was conducted for each variable to identify statistically significant predictors of nCPAP requirement.ResultsTwenty‐eight (17%) of the 163 admitted infants received nCPAP. The strongest predictors of nCPAP requirement in were as follows: oxygen requirement within the ED (P < 0.001), lower oxygen saturation (P < 0.001), younger age at presentation (P = 0.002), higher respiratory rate (P = 0.002), higher heart rate (P = 0.003), lower Glasgow Coma Scale score (0.006), and younger gestational age (P = 0.024).ConclusionWe have identified clinical variables that were predictive of nCPAP requirement in infants admitted to our unit with bronchiolitis, oxygen requirement in the ED being the strongest single predictor. This is the first such study in the UK, and we hope it may be a starting point for further work that may provide an evidence base to aid clinicians in predicting the use of nCPAP in infants with bronchiolitis. Pediatr Pulmonol. 2012; 47:381–385. © 2011 Wiley Periodicals, Inc.
Ventilation homogeneity improves with growth early in life
Authors: Chakr Valentina C. , Llapur Conrado J. , Sarria Edgar E. , Mattiello Rita , Kisling Jeffrey , Tiller Christina , Kimmel Risa , Poindexter Brenda , Tepper Robert S. 
Published: September 2011

AbstractSome studies have suggested that lung clearance index (LCI) is age‐independent among healthy subjects early in life, which implies that ventilation distribution does not vary with growth. However, other studies of older children and adolescents suggest that ventilation becomes more homogenous with somatic growth. We describe a new technique to obtain multiple breath washout (MBWO) in sedated infants and toddlers using slow augmented inflation breaths that yields an assessment of LCI and the slope of phase III, which is another index of ventilation inhomogeneity. We evaluated whether ventilation becomes more homogenous with increasing age early in life, and whether infants with chronic lung disease of infancy (CLDI) have increased ventilation inhomogeneity relative to full‐term controls (FT). FT (N = 28) and CLDI (N = 22) subjects between 3 and 28 months corrected‐age were evaluated. LCI decreased with increasing age; however, there was no significant difference between the two groups (9.3 vs. 9.5; P = 0.56). Phase III slopes adjusted for expired volume (SND) increased with increasing breath number during the washout and decreased with increasing age. There was no significant difference in SND between full‐term and CLDI subjects (211 vs. 218; P = 0.77). Our findings indicate that ventilation becomes more homogenous with lung growth and maturation early in life; however, there is no evidence that ventilation inhomogeneity is a significant component of the pulmonary pathophysiology of CLDI. Pediatr Pulmonol. 2012; 47:373–380. © 2011 Wiley Periodicals, Inc.
Serial interferon‐γ release assay in children with latent tuberculosis infection and children with tuberculosis
Authors: Nenadić Nataųa , Kirin Branka Kristić , Letoja Ivka Zoričić , Plavec Davor , Topić Renata Zrinski , Dodig Slavica 
Published: September 2011

AbstractBackgroundInterferon‐γ (IFN‐γ) release assay (IGRA) is used for diagnosis of latent tuberculosis infection (LTBI), and for serial testing of active tuberculosis (TB). The aim of this study was to evaluate the results of IGRA for diagnosis and treatment monitoring of children with LTBI and children with TB. IGRA was performed in BCG vaccinated children before and six months after the beginning of treatment.MethodsA total of 59 BCG vaccinated children aged 4–18 years were investigated due to exposure to active TB. The participants were divided into two groups: Group 1, children with LTBI (N = 41), and Group 2, children with TB (N = 18). IGRA (QuantiFERON‐TB Gold In‐Tube) was performed twice, i.e., before treatment and at the end of prophylaxis and therapy.ResultsThere was no significant difference in IFN‐γ concentrations between Group 1 and Group 2 subjects either before or after the treatment. Difference between pre‐treatment and post‐treatment IFN‐γ concentrations compared in either Group 1 or Group 2 was not statistically significant. During follow‐up, children with LTBI did not develop active TB. In addition, in children with TB, signs and symptoms of TB improved with anti‐TB therapy.ConclusionThis study showed that the concentrations of IFN‐γ did not differ in children with LTBI and TB either before or at the end of treatment. IGRA may remain positive over a long period of time. It seems that IGRA is not useful for monitoring treatment of children with LTBI and children with TB. Pediatr Pulmonol. 2012; 47:401–408. © 2011 Wiley Periodicals, Inc.
Calculation of rate spectra from noisy time series data
Authors: Voelz Vincent A. , Pande Vijay S. 
Published: September 2011

AbstractAs the resolution of experiments to measure folding kinetics continues to improve, it has become imperative to avoid bias that may come with fitting data to a predetermined mechanistic model. Toward this end, we present a rate spectrum approach to analyze timescales present in kinetic data. Computing rate spectra of noisy time series data via numerical discrete inverse Laplace transform is an ill‐conditioned inverse problem, so a regularization procedure must be used to perform the calculation. Here, we show the results of different regularization procedures applied to noisy multiexponential and stretched exponential time series, as well as data from time‐resolved folding kinetics experiments. In each case, the rate spectrum method recapitulates the relevant distribution of timescales present in the data, with different priors on the rate amplitudes naturally corresponding to common biases toward simple phenomenological models. These results suggest an attractive alternative to the “Occam's razor” philosophy of simply choosing models with the fewest number of relaxation rates. Proteins 2012. © 2011 Wiley Periodicals, Inc.
Electron‐beam induced phase transformation in β‐Ag2Se thin films
Authors: Yin Kuibo , Xia Yidong , Liu Zhiguo , Yin Jiang , Sun Litao 
Published: September 2011

AbstractThe microstructure of room‐temperature silver selenide thin films prepared by pulsed laser deposition (PLD) was investigated by transmission electron microscope (TEM). Two phases existed in room‐temperature silver selenide. One was orthorhombic phase (O) and the other was identified as monoclinic phase (M) by TEM tilting experiments. The monoclinic phase can transform to orthorhombic phase along [100]M direction under the irradiation of electron beam. Thermal stress induced by the difference of coefficient of thermal expansion (CTE) of Ag2Se and Cu gridding/NaCl substrate is thought to play an important role in this phase transformation.
Effects of B2O3–Li2O additions on the dielectric properties of screen printing Ba0.6Sr0.4TiO3 thick films
Authors: Zeng Yike , Gao Can , Zhang Guangzu , Jiang Shenglin 
Published: September 2011

AbstractBa0.6Sr0.4TiO3 (BST) thick films were fabricated on Al2O3 substrate via the screen printing technology by using B2O3–Li2O additions as liquid‐phase sintering aids. The effects of doping of B2O3 and Li2CO3 on the phase compositions, microstructures, and dielectric tunable properties of the thick films were investigated systematically. The X‐ray diffraction patterns showed that BST diffraction peaks shifted toward higher angle with the B2O3–Li2O doping content, which indicated the substitution of B3+ and Li+ in Ba2+ site. It was also found that the grain size and electrical properties of the thick film were strongly affected by the glass content. The grain size and the relative permittivity decreased obviously with the increase of B2O3–Li2O additive. In addition, for the thick film with 4.5 wt% glass content, optimized sintering, and electrical properties were obtained: the sintering temperature of 900 °C, relative permittivity of 312 (at 10 kHz), dielectric loss of 0.0039, tunability of 16.2% (at 3 kV/mm). These good sintering and electrical properties indicate that BST thick film with B2O3–Li2O addition is benefit for the development of LTCC technology and tunable devices.
Origin of the waves in ‘A case‐study of mesoscale spectra of wind and temperature, observed and simulated’: Lee waves from the Norwegian mountains
Authors: Larsén Xiaoli Guo , Larsen Søren , Hahmann Andrea N. 
Published: September 2011

AbstractThis note uses SAR images, satellite cloud pictures and point measurements together with simulations using the Weather Research and Forecasting (WRF) model to identify the origin of the gravity waves over Denmark on 6 November 2006, studied recently. The wave characteristics, concerning their initiation and ending, propagation, spatial orientation and wavelength, are consistent among the different data sources. This evidence and the key wave parameters derived from the WRF simulation, including the Scorer parameter and wave tilt, all suggest that the waves are lee waves generated by uplift from the Norwegian mountains. Copyright © 2011 Royal Meteorological Society
Differential heating influence on hailstorm vortex pair evolution
Authors: Ćurić M. , Janc D. 
Published: September 2011

AbstractWe study herein the relationship between hailstorm vortex pair evolution and complex orography. In particular, the effects of differential heating are analysed to evaluate how they can affect the propagation of split hailstorms over complex terrain and impact on the spatial distribution of hail. For these reasons, this investigation is targeted at the characteristics of intense hailstorms over a particular area which is well‐known as their source, as well as the hail point‐frequency spatial distribution over such an area. The methods used include observations and a numerical cloud model. The investigations lead to the following findings.The key mechanism for a favoured right‐moving split hailstorm under strong low‐level directional shear is found. This is differential heating of the sunward and sunshaded sides of the valley. For this reason, stronger convection over the sunward side of the valley compared to that over its sunshaded side leads to a weaker vertical wind shear. In such a scenario, additional vertical vorticity components are generated that weaken the former existing vortices. The resulting effect is stronger weakening of the anticyclonic part of the cloud than its cyclonic counterpart. Finally, we have established the conceptual model of the vortex pair modified by differential heating.The other findings are as follows: the spatial distribution of the maximum values of hail point‐frequency associated with air‐mass hailstorms is well correlated with the tracks of split hailstorms. It shows the regular spatial pattern due to the corresponding cell‐regeneration behaviour. As a consequence, hail point‐frequency maxima more often occur in the valley than over the nearby areas. Hail point‐frequency maximum locations associated with frontal clouds are more or less uniform in the along‐line direction of a front. Copyright © 2011 Royal Meteorological Society
Moving average correction method for compensation of differential column shortenings in high‐rise buildings
Authors: Woo Park Sung , Woon Choi Se , Seon Park Hyo 
Published: September 2011

SUMMARYThe differential length changes of vertical members in a high‐rise building due to elastic, creep and shrinkage shortenings are of primary concern since the differential shortening of the vertical members causes unexpected damages on structural and nonstructural members. In contrast to researches on prediction methods for calculation of the amount of the shortenings, only few methods or algorithms of compensation of the differential column shortenings have been reported. In this paper, a practical compensation method using moving average correction is presented. The proposed method is applied to the compensation of the differential shortenings of the vertical members in a 70‐story high‐rise building. The performance of the moving average correction method is compared with the optimal compensation method based on simulated annealing algorithm. It is demonstrated that the magnitude of the differential shortening or the degree of the slab tilt due to the length changes in the vertical members can be controlled without using structural optimization techniques. Copyright © 2011 John Wiley & Sons, Ltd.
Slowmation: Preservice elementary teachers representing science knowledge through creating multimodal digital animations
Authors: Hoban Garry , Loughran John , Nielsen Wendy 
Published: September 2011

AbstractResearch has identified the value of learners using technology to construct their own representations of science concepts. In this study, we investigate how learners, such as preservice elementary teachers, design and make a narrated animation to represent their science knowledge. The type of animation exemplified is called a “Slowmation” (abbreviated from “Slow Animation”), which is a simplified way for preservice teachers to make an animation that integrates features from claymation, object animation, and digital storytelling. Drawing on semiotic theory, a case study of three preservice elementary teachers, who were audio and video recorded as they created a slowmation, illustrates how the construction process enabled them to engage with a science concept in multiple ways. Findings suggest that when preservice teachers create a slowmation, they design and make a sequence of five representations, each being a semiotic system with particular affordances that link as a semiotic progression: (i) research notes; (ii) storyboard; (iii) models; and (iv) digital photographs, which culminate in (v) a narrated animation. In this study, the authors present their theoretical framework, explain how the preservice teachers created a slowmation using a sequence of representations to show their science knowledge and discuss the implications of these findings for learners in universities and schools. © 2011 Wiley Periodicals, Inc. J Res Sci Teach 48: 985–1009, 2011
Student learning in science simulations: Design features that promote learning gains
Authors: Scalise Kathleen , Timms Michael , Moorjani Anita , Clark LaKisha , Holtermann Karen , Irvin P. Shawn 
Published: September 2011

AbstractThis research examines science‐simulation software available for grades 6–12 science courses. The study presented, funded by the National Science Foundation, had two objectives: a literature synthesis and a product review. The literature synthesis examines research findings on grade 6–12 student learning gains and losses using virtual laboratories and science‐simulation software, derived from a review of 79 relevant studies identified. Based on that literature, significant aspects of how such products influence student learning are identified. Tables summarize the research‐based evidence about best practices in instructional design for such virtual lab and simulation products. Some products were then reviewed as case studies to determine in what ways and to what extent they implement such research‐identified best practices. The overall goal was to consider where the most progress is being made in effective virtual‐lab and simulation products, and what directions future development should take. The intent is to inform science educators, teachers, administrators, and policy makers who are using, buying, and examining middle and high school instructional materials. © 2011 Wiley Periodicals, Inc. J Res Sci Teach 48: 1050–1078, 2011