bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the electrospinning of PVDF: influence of the experimental conditions on the nanofiber properties
Authors: Cozza Erika Simona , Monticelli Orietta , Marsano Enrico , Cebe Peggy 
Published: July 2012

AbstractThe characteristics of poly(vinylidene fluoride) (PVDF) nanofibers, prepared by applying the electrospinning technique from N,N‐dimethylformamide/acetone mixtures, were studied by varying the experimental conditions. The nanofiber morphology was assessed by scanning electron microscopy, while wide angle X‐ray diffraction and infrared spectroscopy were performed to study the crystallinity. The influence of the electrospinning conditions, such as kind of solvent mixture, polymer concentration, voltage tension, airflow and humidity, on nanofiber morphology was studied. In particular, the latter parameter, generally not considered, was found to modify the electrospun mat structure in a relevant way. Generally, the above technique turns out to be capable of strongly affecting the polymorphism of the polymer, namely β phase formation was higher in the electrospun mats compared with cast films, which displayed a non‐polar α crystal phase. As far as the influence of the electrospinning conditions on PVDF crystal structure is concerned, modification of the experimental parameters did not affect the α/β ratio. Nevertheless, comparing the behavior of two commercial PVDF samples with similar molecular masses, our results show that the polymer which forms a higher content of β phase in its cast films allowed electrospun mats characterized by almost complete formation of β phase to be obtained. Copyright © 2012 Society of Chemical Industry
Isolation of π‐conjugated system through polyfluorene from electronic coupling with side‐chain substituents by cardo structures
Authors: Yeo Hyeonuk , Tanaka Kazuo , Chujo Yoshiki 
Published: July 2012

AbstractThe electronic coupling via the cardo structure in polyfluorene (PFs) was investigated. The series of fluorene units alternatively having alkoxyphenyl as an electron‐donating group (EDG) and/or alkyl benzoate as an electron‐withdrawing group (EWG) at the cardo carbon were synthesized. From the investigation of optical properties of the polymers containing these fluorene units, it was found that the electronic states of the substituents at the cardo carbons and the PF main chains should be less influenced by the introduction of EDG and/or EWG at the cardo structure. Furthermore, these preservation effects in the cardo‐PFs were observed in the film states even after the thermal treatment. We conclude that the electronic structures of the PF main chain are highly preserved from the correlations with the substituents at the cardo carbons. This is the first example, to the best of our knowledge, to survey the systematic information on the electronic structures of the cardo‐PFs and offer the preservation effect of the optical properties from the introduction of EDGs and EWGs at the cardo carbon. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Isotropic–nematic phase separation and demixing in mixtures of spherical nanoparticles with length‐polydisperse nanorods
Authors: Green Micah J. 
Published: July 2012

AbstractAn extension of Onsager theory is developed to simulate isotropic–nematic phase separation in a mixture of spheres with length‐polydisperse system of rods. This work is motivated by recent experimental data on nanorod liquid crystals. Prior theoretical investigations indicate that both polydispersity and the presence of spheres should increase the biphasic–nematic phase transition, that is, the nematic cloud point. Results indicate that the phase diagrams undergo drastic changes depending upon both particle geometry and rod length polydispersity. The key geometric factor is the ratio between the sphere diameter and the rod diameter. In general, length fractionation is enhanced by the addition of spheres, which may be experimentally advantageous for separating short nanorods from a polydisperse population. Simulation results also indicate that the nematic cloud and shadow curves may cross one another because of the scarcity of spheres in the shadow phase. In general, these results do indicate that the nematic cloud point increases as a function of sphere loading; however, in certain areas of phase space, this relationship is nonmonotonic such that the nematic cloud point may actually decrease with the addition of spheres. This work has application to a wide range of nanoparticle systems, including mixtures of spherical nanoparticles with nanorods or nanotubes. Additionally, a number of nonspherical particles and structures may behave as spheres, including crumpled graphene and tightly coiled polymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Promoting consultation recording practice in oncology: identification of critical implementation factors and determination of patient benefit
Authors: Hack Thomas F. , Ruether J. Dean , Weir Lorna M. , Grenier Debjani , Degner Lesley F. 
Published: July 2012

AbstractObjectiveThe objectives of this implementation study were to (i) address the evidentiary, contextual, and facilitative mechanisms that serve to retard or promote the transfer and uptake of consultation recording use in oncology practice and (ii) follow patients during the first few days following receipt of the consultation recording to document, from the patient's perspective, the benefits realized from listening to the recording.MethodsNine medical and nine radiation oncologists from cancer centers in three Canadian cities (Calgary, Vancouver, and Winnipeg) recorded their primary consultations for 228 patients newly diagnosed with breast (n = 174) or prostate cancer (n = 54). The Digital Recording Use Semi‐Structured Interview was conducted at 2 days and 1 week postconsultation. Each oncologist was provided a feedback letter summarizing the consultation recording benefits reported by their patients.ResultsSixty‐nine percent of patients listened to at least a portion of the recording within the first week following the consultation. Consultation recording favorableness ratings were high: 93.6% rated the intervention between 75 and 100 on a 100‐point scale. Four main areas of benefit were reported: (i) anxiety reduction; (ii) enhanced retention of information; (iii) better informed decision making; and (iv) improved communication with family members. Eight fundamental components of successful implementation of consultation recording practice were identified.ConclusionsFurther randomized trials are recommended, using standardized measures of the patient‐reported benefit outcomes reported herein, to strengthen the evidence base for consultation recording use in oncology practice. Copyright © 2012 John Wiley & Sons, Ltd.
Respiratory function at age 8–9 after extremely low birthweight or preterm birth in Victoria in 1997
Authors: Hacking Douglas F. , Gibson Anne‐Marie , Robertson Colin , Doyle Lex W. ,   for the Victorian Infant Collaborative Study Group (VICS)
Published: July 2012

AbstractTo determine if respiratory function at 8 years of age in extremely low birth weight (ELBW; birth weight <1,000 g) or extremely preterm (EPT, <28 weeks' gestation) children born in 1997 remains worse than normal birth weight (NBW; birth weight, >2,499 g) and term (37–42 weeks) controls, particularly in those ELBW/EPT children who had bronchopulmonary dysplasia (BPD). This was a cohort study of 201 consecutive ELBW/EPT survivors born in the state of Victoria during 1997, and 199 contemporaneous randomly selected NBW/term controls. Respiratory function was measured at 8 years of age according to standard guidelines, and compared with previous cohorts born in 1991–1992. Respiratory function data were available for almost 75% of both cohorts. ELBW/EPT subjects had substantial reductions in airflow compared with controls (e.g., mean difference in forced expiratory volume in 1 sec [FEV1] −0.91 SD, 95% confidence interval [CI] −1.19 to −0.63 SD, and in maximum expiratory flow between 25% and 75% of vital capacity [FEF25–75%] −0.96 SD, 95% CI −1.22 to −0.71). These differences were similar to those observed between ELBW/EPT and controls subjects born in 1991–1992. Within the ELBW/EPT cohort, children who had BPD in the newborn period had significant reductions in both the FEV1 (−0.76 SD) and FEF25–75% (−0.58 SD) compared with those who did not have BPD, which were not statistically significant from those in the 1991–92 cohort. ELBW/EPT children born in 1997 still have significantly abnormal lung function compared with NBW/term controls, but results were similar to an earlier era when survival rates were lower. Pediatr Pulmonol. 2013; 48:449–455. © 2012 Wiley Periodicals, Inc.
Usefulness of impulse oscillometry and fractional exhaled nitric oxide in children with Eosinophilic bronchitis
Authors: Kim Yoon Hee , Kim Kyung Won , Baek Jiyoung , Park Hyun Bin , Kim Hyemi , Song Kyung‐Joo , Lee Jae Myun , Sohn Myung Hyun , Kim Kyu‐Earn 
Published: July 2012

AbstractBackgroundEosinophilic bronchitis (EB) is a common cause of chronic cough. Although EB shares many immunopathologic features with asthma, it does not show airway hyperresponsiveness or reversible airway obstruction by spirometry.ObjectiveCompared to healthy children without pulmonary disease, we hypothesized that EB patients would demonstrate abnormal pulmonary function and inflammation with impulse oscillometry (IOS) and fractional exhaled nitric oxide (FeNO), which are more sensitive tests of these parameters than spirometry.MethodsA total of 232 children with asthma, 109 with EB, and 115 control subjects were enrolled. We compared pulmonary function parameters and FeNO levels among the three groups. Additionally, we designated a screening cutoff value of FeNO combined with IOS parameters to distinguish EB from the control group, and identify which children with EB have more asthmatic characteristics.ResultsBy IOS, the bronchodilator response of the EB and asthma groups increased significantly compared to controls for both reactance at 5 Hz (Δ X5) and reactance area (Δ AX) (P < 0.0001). Cutoff values to distinguish EB from controls were a Δ X5 of −20% (sensitivity, 77.5%; specificity, 49.6%), and Δ AX of −30% (sensitivity, 75.0%; specificity, 46.0%), when the FeNO is 20 ppb.ConclusionsReversible airway obstruction in IOS and elevated FeNO levels can be detected in children with EB. This would support that EB in children shows airway characteristics similar to those of asthma, and that a continuum exists between asthma and EB. Pediatr Pulmonol. 2013; 48:221–228. © 2012 Wiley Periodicals, Inc.
Classic kaposi sarcoma with pulmonary involvement mimicking endobronchial tuberculosis in a child
Authors: Cakir Fatma B. , Cakir Erkan , Tuzuner Nukhet , Kut Arif 
Published: July 2012

AbstractKaposi' sarcoma (KS) is a low‐grade vascular neoplasm and classic KS, a subtype of KS, is extremely rare in children. Childhood pulmonary involvement in classic KS has not been reported in the literature. We describe an HIV‐seronegative pediatric case with a fulminant course of classic KS with pulmonary involvement mimicking endobronchial tuberculosis. Pediatr Pulmonol. 2013; 48:310–312. © 2012 Wiley Periodicals, Inc.
Electrodeposition of a Pt–PrO2−x electrocatalyst on diamond electrodes for the oxidation of methanol
Authors: Chen Liang , Hu Jingping , Foord John S. 
Published: July 2012

AbstractThe electrodeposition of Pt–PrO2−x nanostructures on boron‐doped diamond electrodes was explored by decorating platinum nanoparticles with praseodymium oxide, for application as an electrocatalyst in the electrooxidation of methanol in direct methanol fuel cells. A high loading of platinum with good stability was deposited by adopting a two‐stage protocol, which involved a stepped potential route and a chronoamperometric approach. Praseodymium oxide was then coated on the platinum particles from solutions containing praseodymium nitrate and hydrogen peroxide. The porous microstructure of the resulting catalyst was characterized by X‐ray photoelectron spectroscopy and scanning electron microscope, along with electrochemical measurement. The addition of praseodymium oxide to the Pt resulted in a higher catalytic activity profile for methanol oxidation along with an improved resistance to poisoning effects caused by incompletely oxidized carbonaceous species.
Etch‐pit formation mechanism induced on HPHT and CVD diamond single crystals by H2/O2 plasma etching treatment
Authors: Naamoun M. , Tallaire A. , Silva F. , Achard J. , Doppelt P. , Gicquel A. 
Published: July 2012

AbstractH2/O2 plasma treatments offer advantages over other etching processes of diamond as a technique to prepare the substrate surface prior to chemical vapor deposition (CVD) diamond growth. It allows removing defects induced on the surface by polishing, thus leading to an improved morphology and limiting the stress within the grown crystal. Moreover, they present the advantage to be performed in situ just before the CVD diamond growth. In this work, H2/O2 plasma treatments were performed so that threading dislocations and other defects are etched preferentially, thus leaving typical etch‐pits. The defect densities in several high pressure high temperature (HPHT) and CVD diamond crystals were then quantified and compared; in particular defects originating from polishing could be distinguished from extended defects inside the crystal. Furthermore, the defect density was found to be of the order of 105/cm2 for HPHT crystals, which was approximately one order of magnitude lower than that measured in low cost commercial CVD monocrystals. The use of laser microscopy also allowed observing the morphology, size and depth of different etch‐pits of 〈001〉‐oriented and misoriented crystals and their evolution with etching time in order to get a better understanding of defect density and formation during CVD growth.
Luminescence of defects and breakdown sites in multicrystalline silicon solar cells
Authors: Mankovics D. , Klossek A. , Krause Ch. , Arguirov T. , Seifert W. , Kittler M. 
Published: July 2012

AbstractWe studied the correlation between the appearance of defects and of breakdowns in fully processed solar cells by electroluminescence imaging. Images under forward and reverse bias were recorded, revealing defective areas and breakdown sites of the cells, respectively. In the experiments presented here an InGaAs camera system was used, which allows us to detect short wave infrared light in the 900–1700 nm range. Applying a forward bias the band‐to‐band luminescence (1.1 eV/1150 nm) and the defect‐related luminescence (0.8 eV/1550 nm) were imaged. Both imaging techniques reveal mainly dislocation‐rich areas and grain boundaries. Applying a reverse bias (approximately −10 V), breakdown luminescence occurs. It was found that the distribution of the breakdown sites across the solar cells is different from the distribution of the defects showing luminescence at 0.8 eV (grain boundaries, dislocations). The spatial separation between those defects and the breakdown sites was clearly evidenced by high resolution imaging. Possible reasons for such spatial separation are discussed.
A re‐examination of cobalt‐related defects in n‐ and p‐type silicon
Authors: Scheffler Leopold , Kolkovsky Vladimir , Weber Jörg 
Published: July 2012

AbstractIn the present work cobalt‐doped n‐ and p‐type silicon samples were studied by means of deep level transient spectroscopy (DLTS) and Laplace‐DLTS (LDLTS). We demonstrate that two dominant DLTS peaks previously assigned to a substitutional Co defect have different annealing behaviour and therefore belong to different defects. After wet chemical etching three other peaks (E90, E140 and H160) were observed in the samples. The intensity of the peaks becomes larger in the H‐plasma treated samples. This together with depth profiling demonstrates that the peaks are hydrogen‐related defects. The origin of the peaks will be discussed.
Electrospray ionisation mass spectrometric studies for the determination of palladium after pre‐concentration by disposable pipette extraction
Authors: Jaison P. G. , Kumar Pranaw , Telmore Vijay M. , Aggarwal Suresh K. 
Published: July 2012

RATIONALEElectrospray ionisation mass spectrometric (ESI‐MS) analysis of Pd in complex matrices is difficult due to the multiplicity of matrix effects. Two different approaches, internal standard and matrix separation, were investigated for developing a reliable analytical procedure for the trace level determination of Pd in simulated high‐level liquid waste (SHLLW) solutions.METHODSAn ESI mass spectrometer with a quadrupole‐time‐of‐flight analyser was used to study the speciation of the palladium‐benzoylthiourea (Pd‐BTU) complex and to determine the Pd content. The Pd‐BTU complex was selectively pre‐concentrated using disposable pipette extraction (DPX). Extraction parameters as well as ESI‐MS parameters such as concentration of BTU, acidity, composition of medium and capillary voltage, etc., were optimized based on the major species [Pd(BTU)2S]+.RESULTSThe method gave quantitative and selective pre‐concentration of the Pd‐BTU complex from SHLLW. Linearity from 5 ppb to 200 ppb and a limit of detection of 0.012 ppb were obtained for Pd. No interference from the neighboring elements, viz. ruthenium, rhodium, silver and cadmium, was observed during the determination of Pd based on the [Pd(BTU)2S]+peak. The ESI signal intensity was not influenced by the presence of the many other elements in the SHLLW solution.CONCLUSIONSGood sensitivity, tolerance to matrix concentration and the absence of interference from neighboring elements make the method very promising for the determination of Pd at low levels in complex samples. We have demonstrated the capability of ESI‐MS for the quantification of Pd in complex matrices and its potential for providing data on speciation, using the Pd‐BTU complex. Copyright © 2012 John Wiley & Sons, Ltd.
Characterization of lipid A profiles from Shigella flexneri variant X lipopolysaccharide
Authors: Casabuono Adriana C. , van der Ploeg Claudia A. , Rogé Andrés D. , Bruno Susana B. , Couto Alicia S. 
Published: July 2012

RATIONALEIn developing countries, Shigella flexneri (Sf) is the major causative agent of the endemic shigellosis (bacillary dysentery) responsible annually for one million fatalities mostly among infants. Lipopolysaccharides (LPSs) are characteristic components of the outer membrane of the overwhelming majority of Gram‐negative bacteria. Since lipid A is essential for the viability of the Gram‐negative bacteria, it is subject to extensive chemical studies with new analytical techniques.METHODSLipid A was released by mild acid hydrolysis from the lipopolysaccharide which was obtained via the phenol/water extraction, purified and analyzed by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) and matrix‐assisted laser desorption/ionization laser‐induced dissociation tandem mass spectrometry (MALDI‐LID‐MS/MS).RESULTSA detailed structural study of the whole lipid A obtained from S. flexneri variant X was carried out for the first time. Thus, we have shown that lipid A is a heterogeneous mixture having different numbers of acylated and phosphoethanolamine groups attached to the diglucosamine backbone. Furthermore, we found in the phenol phase an unusual hepta‐acylated lipid A species, although the abundance was very low.CONCLUSIONSMALDI‐TOF‐MS allowed us to unravel the lipid A heterogeneity, which was not previously reported in Sf LPS. It is well known that slight variations of the chemical structure of lipid A may change its biological activity. Thus, the knowledge of the detailed chemical structure represents an essential step for further development of new preventive or therapeutically active compounds. Copyright © 2012 John Wiley & Sons, Ltd.
Identification, quantification and carbon stable isotopes determinations of organic acids in monofloral honeys. A powerful tool for botanical and authenticity control
Authors: Daniele Gaëlle , Maitre Dany , Casabianca Hervé 
Published: July 2012

RATIONALEThe analytical composition and botanical origin of honey are basic data used to determine the quality of this foodstuff. Although proteins are used to characterise the analytical composition of honey, they can be eliminated during its ultrafiltration and, in the case of honeys not saturated with their own pollen, the use of proteins does not work well. As acidity is a well‐known characteristic of honey and organic acids are present at around 0.5% in honey, we therefore investigated an alternative method to the protein‐based White method, using organic acids as new internal standards instead of proteins.METHODSThe qualitative and quantitative analyses of 14 organic acids were carried out by ion chromatography with an electrochemical detector. The 13C/12C isotopic ratios of the honeys, and of the organic acids extracted from them with an anion exchange resin, were determined by isotope ratio mass spectrometry.RESULTSGluconic acid is the predominant organic acid in honey, at between 1.8 and 12.7 g/kg. For fir honey the major acid is galacturonic acid at around 4.6 g/kg. The isotopic ratios of honeys and of their acids are strongly linked. Correlations between the δ13C values of the honey and the acids were significant, and better than those obtained using proteins.CONCLUSIONSThis study has provided a method to differentiate honeys from seven botanical origins, based on organic acid analysis. By combining various organic acid contents and isotopic ratio values through statistical processing by Principal Component Analysis it is possible to differentiate honey samples as a function of their botanical origin. Copyright © 2012 John Wiley & Sons, Ltd.
Development of liquid chromatography/mass spectrometry based screening assay for PfTrxR inhibitors using relative quantitation of intact thioredoxin
Authors: Munigunti Ranjith , Calderón Angela I. 
Published: July 2012

RATIONALEPlasmodium falciparum (Pf) thioredoxin reductase (TrxR) catalyzes the reduction of thioredoxin disulfide (Trx–S2) to thioredoxin dithiol (Trx–(SH)2) that is essential for antioxidant defense mechanism and DNA synthesis in the parasite and is a validated drug target for new antimalarial agents.METHODSIn this study, we have developed a liquid chromatography/mass spectrometry (LC/MS)‐based functional assay to identify inhibitors of PfTrxR by quantifying the product formed (Trx–(SH)2) in the enzymatic reaction. Relative quantitation of the reaction product (intact Trx–(SH)2) was carried out using an Agilent 6520 QTOF mass spectrometer equipped with a positive mode electrospray ionization (ESI) source.RESULTSThe calibration curve prepared for Trx–(SH)2 at concentrations ranging from 1.8 to 116.5 µg/mL was linear (R2 >0.998). The limit of detection (LOD) and limit of quantification (LOQ) of Trx–(SH)2 were at 0.45 and 1.8 µg/mL respectively. To validate the developed functional assay we have screened reference compounds 1, 2 and 3 for their PfTrxR inhibitory activity and ten natural compounds (at 10 μM) which were earlier identified as ligands of PfTrxR by a UF‐LC/MS based binding assay.CONCLUSIONSThe developed LC/MS‐based functional assay for identification of inhibitors of PfTrxR is a sensitive and reliable method that is also amendable for high‐throughput format. This is the first representation of a relative quantitation of intact Trx–(SH)2 using LC/MS. Copyright © 2012 John Wiley & Sons, Ltd.