bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermophysical properties of bacterial poly(3‐hydroxybutyrate): Characterized by TMA, DSC, and TMDSC
Authors: Wei Liqing , McDonald Armando G. 
Published: May 2015

ABSTRACTThe melting, isothermal and nonisothermal crystallization behaviors of poly(3‐hydroxybutyrate) (PHB) have been studied by means of temperature modulated differential scanning calorimetry (TMDSC) and conventional DSC. Various experimental conditions including isothermal/annealing temperatures (80, 90, 100, 105, 110, 120, 130, and 140°C), cooling rates (2, 5, 10, 20, and 50°C/min) and heating rates (5, 10, 20, 30, 40, and 50°C/min) have been investigated. The lower endothermic peak (Tm1) representing the original crystals prior to DSC scan, while the higher one (Tm2) is attributed to the melting of the crystals formed by recrystallization. Thermomechanical analysis (TMA) was used to evaluate the original melting temperature (Tmelt) and glass transition temperature (Tg) as comparison to DSC analysis. The multiple melting phenomenon was ascribed to the melting‐recrystallization‐remelting mechanism of the crystallites with lower thermal stability showing at Tm1. Different models (Avrami, Jeziorny‐modified‐Avrami, Liu and Mo, and Ozawa model) were utilized to describe the crystallization kinetics. It was found that Liu and Mo's analysis and Jeziorny‐modified‐Avrami model were successful to explain the nonisothermal crystallization kinetic of PHB. The activation energies were estimated in both isothermal and nonisothermal crystallization process, which were 102 and 116 kJ/mol in respective condition. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42412.
Creatinine adsorption capacity of electrospun polyacrylonitrile (PAN)‐zeolite nanofiber membranes for potential artificial kidney applications
Authors: Lu Limin , Samarasekera Champika , Yeow John T.W. 
Published: May 2015

ABSTRACTInnovative dialysis membranes are needed for dialysis, which is the primary treatment for patients with end stage renal disease. In this study, we developed a polyacrylonitrile zeolite nanofiber composite membrane using an electrospinning process to adsorb uremic toxins through molecular sieve mechanism. Scanning electron microscope images revealed that the average diameter of the fiber fabricated with 10 wt % polyacrylonitrile was 673 nm and that of polyacrilonitirle‐zeolite membranes were 277−419 nm. The creatinine adsorption behavior of 500‐KOA (L), 720‐KOA (Farrierite), 840‐NHA (ZSM‐5), and 940‐HOA (Beta) zeolite powders were investigated. Among all the zeolites, 940‐HOA zeolites showed the best performance. The creatinine adsorption capacity of 940‐zeolite powders increased from 2234 µg/g in 50 µmol/L creatinine solution to 25423 µg/g in 625 µmol/L creatinine solution. The speed of adsorption was very quick; 0.025 g of 940‐zeolite powders can eliminate 91% of 2 µmol creatinine in 5 min. The zeolites incorporated inside the membrane had higher creatinine adsorption capacity than free zeolites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42418.
Hybrid biocomposites with enhanced thermal and mechanical properties for structural applications
Authors: Birat KC , Panthapulakkal Suhara , Kronka Andrei , Agnelli Jose Augusto M. , Tjong Jimi , Sain Mohini 
Published: May 2015

ABSTRACTThe current work focuses on enhancing the mechanical and thermal properties of sisal fiber reinforced composites that were previously used in developing interior automotive trims. In order to extend their use in other structural applications, two hybrid biocomposites with the combination of sisal (SF) and glass fiber (GF)‐SF20/GF10 and SF10/GF20 were blended with polypropylene via extrusion and injection molding process. Critical material properties such as density, fogging, acoustic, mechanical, thermal, and rheological properties were evaluated and results were analyzed using ANOVA. Hybridization of SF and GF enhanced flexural strength and thermal properties of the biocomposites by 33 and 19%, respectively, while no significant change in acoustic, impact and rheological properties were observed. The properties of the hybrid biocomposites were compared with the material specification of a battery tray and it was found that these hybrid biocomposites could be better alternative materials in structural applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42452.
Linear and nonlinear viscoelasticity of oleogels based on vegetable oil and ethylene vinyl acetate copolymer/isotactic polypropylene blends
Authors: Alfonso Jose Enrique Martín , Valencia Concepción 
Published: May 2015

ABSTRACTThis work deals with a rheological study of oleogels based on high‐oleic sunflower oil (HOSO) and ethylene vinyl acetate copolymer (EVA) / isotactic polypropylene (iPP) blends. EVA copolymers with different vinyl acetate content were used. With this aim, linear small amplitude oscillatory shear (SAOS) and nonlinear (relaxation) measurements combined with polarized optical microscopy were carried out. Oleogels were prepared by using the mixing rheometry technique in a batch mixer. Oscillatory strain amplitude sweep tests showed that the end from the viscoelastic linear region for oleogels was accompanied by opposite trends for viscoelastic moduli. SAOS tests showed that all the oleogels present similar behavior characteristic of polymeric systems with physical entanglements. It was found that the elastic equilibrium modulus and loss tangent increases with iPP content. On the other hand, nonlinear relaxation tests presented a strong dependence on the strain applied and the Soskey–Winter model was found to provide an accurate description of the damping function of these oleogels. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42477.
Regulation of Inflammation and Angiogenesis in Giant Cell Arteritis by Acute‐Phase Serum Amyloid A
Authors: O'Neill Lorraine , Rooney Peadar , Molloy Danielle , Connolly Mary , McCormick Jennifer , McCarthy Geraldine , Veale Douglas J. , Murphy Conor C. , Fearon Ursula , Molloy Eamonn 
Published: May 2015

ObjectiveGiant cell arteritis (GCA) is pathologically characterized by dysfunctional angiogenesis and inflammatory cell infiltration. Acute‐phase serum amyloid A (A‐SAA) is an acute‐phase reactant, but is also produced at sites of inflammation and may contribute to vascular inflammation in atherosclerosis. This study was undertaken to examine the effect of A‐SAA on proinflammatory pathways and angiogenesis in GCA, using a novel ex vivo temporal artery tissue explant model.MethodsSerum A‐SAA levels were measured by enzyme‐linked immunosorbent assay (ELISA). Temporal artery explants and peripheral blood mononuclear cell (PBMC) cultures were established from patients with GCA. Temporal artery explant morphology, viability, and spontaneous release of proinflammatory mediators following 24‐hour culture were assessed by hematoxylin and eosin, calcein viability staining, and ELISA. Temporal artery explants and PBMC cultures were stimulated with A‐SAA (10 μg/ml), and interleukin‐6 (IL‐6), IL‐8, vascular endothelial growth factor, Ang2, and matrix metalloproteinase 2 (MMP‐2)/MMP‐9 were quantified by ELISA and gelatin zymography. The effect of conditioned medium from temporal artery explants on angiogenesis was assessed using endothelial cell Matrigel tube‐formation assays. Temporal artery explants were also embedded in Matrigel, and myofibroblast outgrowth was assessed.ResultsSerum A‐SAA levels were significantly higher in GCA patients versus healthy controls (P < 0.0001). Intact tissue morphology, cell viability, and spontaneous cytokine secretion were demonstrated in temporal artery explants. A‐SAA treatment induced a significant increase in the levels of IL‐6 and IL‐8 from temporal artery explants (P < 0.05) and IL‐8 from PBMCs (P < 0.05) compared to basal conditions. Conditioned medium from A‐SAA–treated explants significantly induced angiogenic tube formation (P < 0.05 versus basal controls). Finally, A‐SAA induced myofibroblast outgrowth and MMP‐9 activation.ConclusionOur findings demonstrate a functional role for A‐SAA in regulating temporal artery inflammation, angiogenesis, and invasion, all key processes in the pathogenesis of GCA.
Reset Control Systems With Time‐Varying Delay: Delay‐Dependent Stability And Gain Performance Improvement
Authors: Zhao Guanglei , Wang Jingcheng 
Published: May 2015

AbstractThis paper considers the stability analysis of reset control systems with time‐varying delay. Based on sector reset conditions, delay‐dependent exponential stability and finite gain
stability conditions are proposed, and piecewise Lyapunov functions are used such that less conservative results can be obtained, moreover,
gain performance improvement results are presented to show the advantage of reset control. Numerical examples are given to show the effectiveness.
Nitrilase‐catalyzed conversion of (R,S)‐mandelonitrile by immobilized recombinant Escherichia coli cells harboring nitrilase
Authors: Zhang Xin‐Hong , Liu Zhi‐Qiang , Xue Ya‐Ping , Xu Ming , Zheng Yu‐Guo 
Published: May 2015

Abstract(R)‐(−)‐Mandelic acid (R‐MA) is widely used both as a versatile intermediate for pharmaceuticals and a resolving agent in chiral resolution processes. In the current study, to improve the stability of operation, recombinant Escherichia coli cells expressing nitrilase from Alcaligenes faecalis were immobilized for the enantioselective hydrolysis of (R,S)‐mandelonitrile to R‐MA. Different immobilization methods including entrapment matrices, entrapment matrices cross‐linked by cross‐linking and polymerization agents, and direct cross‐linking cells using glutaraldehyde (GA) or bionic silicon were investigated. To facilitate industrial solid–liquid separation, the direct cross‐linking recombinant E. coli cells using diatomite/GA/polyethyleneimine with 135.95% relative activity compared with free cells was chosen using water as the reaction medium. The operational stability of the immobilized cells was obviously superior to that of free cells, without significant activity loss after 28 cycles of batch reaction and the successive production of R‐MA could reach 1.88 M. Moreover, the immobilized cells showed good storage stability with about 52% relative activity after storing for 30 days at 4 °C. Therefore, the immobilized biocatalyst is very promising for upscale production of optically pure R‐MA with high performance and low cost.
Pure rhombohedral Bi1‐xEuxPO4 nano‐/micro‐structures: fast synthesis, shape evolution and luminescence properties
Authors: Yu Dongyan , Liang Yujun , Zhang Mengfei , Li Guogang , Yan Chunjie 
Published: May 2015

AbstractBiPO4 and Eu‐doped BiPO4 crystals were synthesized via a simple precipitation route at room temperature, employing Bi(NO3)3 and (NH4)2HPO4 as the reactants, Eu2O3 as the dopant and citric acid as a template. X‐ray powder diffraction analyses showed that pure rhombohedral BiPO4 form was obtained, and was the preferential orientation growth of the crystal. Field emission scanning electron microscope observations showed that the concentration of Bi3+ obviously changed the products' morphologies from nanosphere, hollow sphere to hexagonal prism. The acidity of the solution and the contents of citric acid and Eu3+ ion tailored the size of the final crystals. Effects of concentration of Eu3+ ion on the luminescence emission intensity were also investigated. Copyright © 2015 John Wiley & Sons, Ltd.
Photophysical and electrochemical properties of a dysprosium‐zinc tetra(4‐sulfonatophenyl)porphyrin complex
Authors: Chen Wen‐Tong , Liu Dong‐Sheng , Xu Ya‐Ping , Luo Qiu‐Yan , Pei Yun‐Peng 
Published: May 2015

AbstractA dysprosium‐zinc porphyrin, [DyZn(TPPS)H3O]n (1) (TPPS = tetra(4‐sulfonatophenyl)porphyrin), was prepared through solvothermal reactions and structurally characterized by single‐crystal X‐ray diffraction analyses. Complex 1 features a three‐dimensional (3‐D) porous open framework that is thermally stable up to 400 °C. Complex 1 displays a void space of 215 Å3, occupying 9.2% of the unit cell volume. The fluorescence spectra reveal that it shows an emission band in the red region. The fluorescence lifetime is 39 µsec and the quantum yield is 1.7%. The cyclic voltammetry (CV) measurement revealed one quasi‐reversible wave with E1/2 = 0.30 V. Copyright © 2015 John Wiley & Sons, Ltd.
Development of highly sensitive sensor system for methane utilizing cataluminescence
Authors: Gong Gu. , Zhu Hua 
Published: May 2015

AbstractA gaseous sensor system was developed for the detection of methane based on its cataluminescence emission. Cataluminescence characteristics and optimal conditions were studied in detail under optimized experimental conditions. Results showed that the methane cataluminescence sensor system could cover a linear detection range from 10 to 5800 ppm (R = 0.9963, n = 7) and the detection limit was about 7 ppm (S/N = 3), which was below the standard permitted concentration. Moreover, a linear discriminant analysis method was used to test the recognizable performance of the methane sensor. It was found that methane, ethane, propane and pentane could be distinguished clearly. Its methane sensing properties, including improved sensitivity, selectivity, stability and recognition demonstrated the TiO2/SnO2 materials to be promising candidates for constructing a cataluminescence‐based gas sensor that could be used for detecting explosive gas contaminants. Copyright © 2015 John Wiley & Sons, Ltd.
A chemiluminescence method to detect hydroquinone with water‐soluble sulphonato‐(salen)manganese(III) complex as catalyst
Authors: Zhang Guangbin , Tang Yuhai , Sun Yang , Yu Hua , Du Wei , Fu Qiang 
Published: May 2015

AbstractA water‐soluble sulphonato‐(salen)manganese(III) complex with excellent catalytic properties was synthesized and demonstrated to greatly enhance the chemiluminescence signal of the hydrogen peroxide − luminol reaction. Coupled with flow‐injection technique, a simple and sensitive chemiluminescence method was first developed to detect hydroquinone based on the chemiluminescence system of the hydrogen peroxide–luminol–sulphonato‐(salen)manganese(III) complex. Under optimal conditions, the assay exhibited a wide linear range from 0.1 to 10 ng mL–1 with a detection limit of 0.05 ng mL–1 for hydroquinone. The method was applied successfully to detect hydroquinone in tap‐water and mineral‐water, with a sampling frequency of 120 times per hour. The relative standard deviation for determination of hydroquinone was less than 5.6%, and the recoveries ranged from 96.8 to 103.0%. The ultraviolet spectra, chemiluminescence spectra, and the reaction kinetics for the peroxide–luminol–sulphonato‐(salen)manganese(III) complex system were employed to study the possible chemiluminescence mechanism. The proposed chemiluminescence analysis technique is rapid and sensitive, with low cost, and could be easily extended and applied to other compounds. Copyright © 2015 John Wiley & Sons, Ltd.
Hairpin formation promoted by the heterochiral dinipecotic acid segment: A DFT study
Authors: Kang Young Kee , Park Hae Sook 
Published: May 2015

ABSTRACTConformational preferences for the turn and β‐hairpin structures of Ala‐based peptides [Ac‐Alan‐(R)‐Nip‐(S)‐Nip‐Alan‐X (n = 0–2; X = NHMe or NMe2)] containing nipecotic acid (Nip) residues were carried out using the density functional M06‐2X and the implicit solvation model SMD in CH2Cl2 and/or water. The turn structure of the (R)‐Nip‐(S)‐Nip segment with a C10 H‐bond between two terminal groups was found to be most preferred (populated at 98.9%) in CH2Cl2; this structure is consistent with IR and 1H NMR results. The stabilities of the β‐hairpins containing the (R)‐Nip‐(S)‐Nip segment as a turn motif relative to the extended structures increased with peptide sequence length. The relative strengths of the H‐bonds between the carbonyl oxygen and the amide hydrogen appeared to be responsible for stabilizing the turn and β‐hairpin structures in CH2Cl2. In addition, the (R)‐Nip‐(S)‐Nip segment exhibited the capability to be incorporated into one of the two β‐turn motifs of gramicidin S (GS). The structure of this GS derivative (GS‐Nip2) was generally similar to the native peptide but was less hydrophobic and it is therefore expected to exhibit lower hemolytic activity; however, further experiments are needed to evaluate its antimicrobial activity. The structure of GS‐Nip2 was somewhat more flexible than GS in solvents of higher polarity. Thus, our calculated results regarding the turn and β‐hairpin motifs of the (R)‐Nip‐(S)‐Nip segment indicate that this structure might be useful for the design of bioactive macrocyclic peptides containing β‐hairpin mimics as well as binding epitopes in protein–protein and protein–nucleic acid recognitions. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 609–617, 2015.
Probing the role of sequence in the assembly of three‐dimensional DNA crystals
Authors: Saoji Maithili , Zhang Daoning , Paukstelis Paul J. 
Published: May 2015

ABSTRACTDNA is a widely used biopolymer for the construction of nanometer‐scale objects due to its programmability and structural predictability. One long‐standing goal of the DNA nanotechnology field has been the construction of three‐dimensional DNA crystals. We previously determined the X‐ray crystal structure of a DNA 13‐mer that forms a continuously hydrogen bonded three‐dimensional lattice through Watson‐Crick and non‐canonical base pairs. Our current study sets out to understand how the sequence of the Watson‐Crick duplex region influences crystallization of this 13‐mer. We screened all possible self‐complementary sequences in the hexameric duplex region and found 21 oligonucleotides that crystallized. Sequence analysis showed that one specific Watson‐Crick pair influenced the crystallization propensity and the speed of crystal self‐assembly. We determined X‐ray crystal structures for 13 of these oligonucleotides and found sequence‐specific structural changes that suggests that this base pair may serve as a structural anchor during crystal assembly. Finally, we explored the crystal self‐assembly and nucleation process. Solution studies indicated that these oligonucleotides do not form base pairs in the absence of cations, but that the addition of divalent cations leads to rapid self‐assembly to higher molecular weight complexes. We further demonstrate that crystals grown from mixtures of two different oligonucleotide sequences contain both oligonucleotides. These results suggest that crystal self‐assembly is nucleated by the formation of the Watson‐Crick duplexes initiated by a simple chemical trigger. This study provides new insight into the role of sequence for the assembly of periodic DNA structures. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 618–626, 2015.
A sensitive and efficient method for trace analysis of some phenolic compounds using simultaneous derivatization and air‐assisted liquid–liquid microextraction from human urine and plasma samples followed by gas chromatography–nitrogen phosphorous detection
Authors: Farajzadeh Mir Ali , Afshar Mogaddam Mohammad Reza , Alizadeh Nabil Ali Akbar 
Published: May 2015

AbstractIn present study, a simultaneous derivatization and air‐assisted liquid–liquid microextraction method combined with gas chromatography–nitrogen phosphorous detection has been developed for the determination of some phenolic compounds in biological samples. The analytes are derivatized and extracted simultaneously by a fast reaction with 1‐flouro‐2,4‐dinitrobenzene under mild conditions. Under optimal conditions low limits of detection in the range of 0.05–0.34 ng mL−1 are achievable. The obtained extraction recoveries are between 84 and 97% and the relative standard deviations are less than 7.2% for intraday (n = 6) and interday (n = 4) precisions. The proposed method was demonstrated to be a simple and efficient method for the analysis of phenols in biological samples. Copyright © 2015 John Wiley & Sons, Ltd.
Highly sensitive HPLC‐DAD method for the assay of gefitinib in patient plasma and cerebrospinal fluid: application to a blood‐brain barrier penetration study
Authors: Fang Luo , Song Yu , Weng Xu , Li Fanzhu , Xu Yaping , Lin Nengming 
Published: May 2015

AbstractThe quantification of intracranial gefitinib (GEF) exposure is limited owing to the sensitivity of analytical equipment. Although mass spectrometry (MS) is the preferred method because of its high sensitivity, the equipment is not available in many laboratories, especially in developing Asian countries. In this paper, we developed a highly sensitive high performance liquid chromatography‐diode array detector (HPLC‐DAD) method for the assay of GEF in human cerebrospinal fluid (CSF) and plasma. GEF was extracted from CSF and plasma by solid‐phase extraction and liquid–liquid extraction, respectively. The chromatographic separation was performed on a C18 column with gradient elution of 0.1% triethylamine solution and acetonitrile, then finally detected at 344 nm. This method was validated and proved to be highly sensitive with a lower limit of quantitation value of 0.11 ng/mL in CSF and 11 ng/mL in plasma. The blood–brain barrier penetration ratio of GEF ranged from 1.48 to 2.41%. This method provides a reliable MS‐independent solution for the quantitation of GEF in patients’ CSF and plasma. Copyright © 2015 John Wiley & Sons, Ltd.
Transcarotid balloon valvuloplasty in neonates and small infants with critical aortic valve stenosis utilizing continuous transesophageal echocardiographic guidance: A 22 year single center experience from the cath lab to the bedside
Authors: Patel Sunil , Saini Ashish P. , Nair Athira , Weber Howard S. 
Published: May 2015

ObjectiveUtilization of continuous transesophageal echocardiographic guidance (cTEE) during transcarotid balloon valvuloplasty (TCBV) in neonates and small infants with critical aortic valve stenosis (AS) allows for continuous hemodynamic assessment and improved outcomes.BackgroundPreferred method of intervention for critical AS remains controversial due to conflicting results.MethodsSince 1992, 30 neonates and small infants with critical AS and adequate left ventricular (LV) volumes underwent TCBV with cTEE. Critical AS was defined as ductal dependent systemic circulation, LV systolic dysfunction, or an echo gradient ≥100 mm Hg with evidence of hypoperfusion.ResultsThe median age at intervention was 4 days (range 1–54 days). Nineteen (63%) patients required PGE1 and 25 (85%) had LV dysfunction. All procedures were performed with cTEE guidance. The initial 15 patients were performed in the cath lab whereas the subsequent 15 patients were performed at the bedside without fluoroscopy. The peak systolic gradient decreased from 70 to 24 mm Hg (P < 0.001). Four (13%) early deaths were secondary to associated cardiac anomalies although one patient developed severe aortic valve insufficiency (AI) immediately post intervention. At discharge, two patients (8%) had ≥ moderate AI. At a mean follow‐up of 9 years (range: 2.2–20 years), there were 15 additional aortic valve interventions. Freedom from aortic valve reintervention at 10 years was 55% and actuarial survival rate at 10 and 15 years was 82%.ConclusionBedsides TCBV with cTEE guidance is effective palliation for neonates and small infants with critical AS and allows for continuous hemodynamic assessment without the use of ionizing radiation. Our early and late results appear comparable to surgical valvotomy. © 2015 Wiley Periodicals, Inc.