bluuebunny/crossref_metadata_2025_split huggingface dataset:
Forecasting scintillation activity and equatorial spread F
Authors: Anderson David N. , Redmon Robert J. 
Published: January 2017

AbstractWhen transionospheric radio waves propagate through an irregular ionosphere with plasma depletions or “bubbles,” they are subject to sporadic enhancement and fading, which is referred to as scintillation. Communication and navigation systems may be subject to these detrimental effects if the scintillation is strong enough. It is critical to have knowledge of the current ionospheric conditions so that system operators can distinguish between the natural radio environment and system‐induced failures. In this paper we briefly describe the Forecasting Ionospheric Real‐time Scintillation Tool UHF scintillation forecasting technique, which utilizes the observed characteristic parameter h′F from a ground‐based, ionospheric sounder near the magnetic equator. The prereversal enhancement in vertical E × B drift velocity after sunset is the prime driver for creating plasma depletions and bubbles. In addition, there exists a “threshold” in the h′F value at 1930 LT, h′Fthr, such that, on any given evening, if h′F is significantly above h′Fthr, then scintillation activity is likely to occur, and if it is below h′Fthr, scintillation activity is unlikely to occur. We use this technique to explain the lack of scintillation activity prior to the Halloween storm in October 2003 in the Peruvian longitude sector. In addition, we have carried out a study which forecasts the occurrence or nonoccurrence of equatorial spread F (ESF), on a night‐to‐night basis, in five longitude sectors. The overall forecasting success is greater than 80% for each of the five longitude sectors.
Subgrid parameterization for snow depth over mountainous terrain from flat field snow depth
Authors: Helbig N. , van Herwijnen A. 
Published: January 2017

AbstractSnow depth is an important variable for a variety of models including land‐surface, meteorological, and climate models. Various measurement networks were therefore developed to measure snow depth on the ground. Measurement stations are generally located in gentle terrain (flat field measurements) most often at lower or mid elevation. While these sites have provided a wealth of information, various studies have questioned the representativity of such flat field measurements for the surrounding topography, especially in alpine regions. Using highly resolved snow depth maps at the peak of winter from two distinct climatic regions in Switzerland and in the Spanish Pyrenees, we developed two parameterizations to estimate domain‐averaged snow depth in coarse‐scale model applications over complex topography using easy to derive topographic parameters. The first parameterization uses a commonly applied linear lapse rate. Removing the dominant elevation gradient in mean snow depth revealed remaining underlying correlations with other topographic parameters, in particular the sky view factor. The second parameterization combines a power law elevation trend scaled with the subgrid parameterized sky view factor. Using a variety of statistic measures showed that the more complex parameterization performs better when using mean high‐resolution flat field snow depth. The performances slightly decreased when formulating the parameterizations for a single flat field snow depth measurement. Nevertheless, the more complex parameterization still outperformed the linear lapse rate model. As the parameterization was developed independently of a specific geographic region, we suggest it could be used to assimilate flat field snow depth or snowfall into coarse‐scale snow model frameworks.
Iron‐Catalyzed Isopropylation of Electron‐Deficient Aryl and Heteroaryl Chlorides
Authors: Sanderson James N. , Dominey Andrew P. , Percy Jonathan M. 
Published: January 2017

AbstractTraditional methods for the preparation of secondary alkyl‐substituted aryl and heteroaryl chlorides challenge both selectivity and functional group tolerance. This contribution describes the use of statistical design of experiments to develop an effective procedure for the preparation of isopropyl‐substituted (hetero)arenes with minimal isopropyl to n‐propyl isomerization. The reaction tolerates electronically diverse aryl chloride coupling partners, with excellent conversion observed for strongly electron‐deficient aromatic rings, such as esters and amides. Electron‐rich systems, including methyl‐ and methoxy‐substituted aryl chlorides, were found to be less reactive. Furthermore, the reaction was found to be most successful when heteroaryl chlorides were submitted to the cross‐coupling protocol. By mapping substituent effects on reaction selectivity, we were able to show that electron‐deficient aryl chlorides are essential for efficient coupling, and use electronic structure calculations to predict the likelihood of successful coupling through the estimation of the electron affinity of each aryl chloride. Moderate isolated yields were achieved with selected aryl chlorides, and moderate to good isolated yields were obtained for all the heteroaryl chlorides coupled. Excellent selectivity was observed when a 2,6‐dichloroquinoline was used, allowing mono‐substitution on a challenging substrate.magnified image
Bactericidal antibiotics promote oxidative damage and programmed cell death in sinonasal epithelial cells
Authors: Kohanski Michael A. , Tharakan Anuj , London Nyall R. , Lane Andrew P. , Ramanathan Murugappan 
Published: January 2017

BackgroundAntibiotics are widely and heavily used in the treatment of chronic sinusitis. Bactericidal antibiotics can stimulate reactive oxygen species (ROS) formation, a proinflammatory response, and cell death in cultured human sinonasal epithelial cells (SNECs). Sulforaphane (SFN) is a potent stimulator of the antioxidant nuclear factor erythroid 2‐related factor 2 (Nrf‐2) system and a suppressor of inflammation. In this study we utilized SFN to further explore the relationship between levofloxacin treatment, ROS formation, and the cell death response.MethodsSNECs were collected from patients during endoscopic sinus surgery and grown in culture at the air‐liquid interface. Differentiated SNECs were stimulated with levofloxacin with or without SFN pretreatment. ROS were quantified. Apoptosis markers of caspase‐3 activity and DNA fragmentation were quantified.ResultsCultured SNECs treated with levofloxacin resulted in a significant increase in activity of the proapoptotic caspase‐3 protease (5.9‐fold, p = 0.01). The increase in activity was suppressed by pretreatment with SFN (1.9‐fold). ROS levels increased with levofloxacin treatment (range, 1.2‐fold to 1.8‐fold), but were not significantly suppressed by pretreatment with SFN (range, 1.0‐fold to 1.3‐fold).ConclusionIn this study, we demonstrate that treatment of cultured SNECs with levofloxacin leads to an increase in caspase‐3 activity. SFN pretreatment suppresses the increased apoptotic response possibly through its antioxidant stimulating properties. Our results suggest that levofloxacin treatment stimulates a potent proapoptotic possibly through an ROS‐dependent mechanism. Future studies will explore if this antibiotic‐induced response is harmful to recovery of function in those with sinusitis.
In situ synthesis of metallophthalocyanines into pores of MIL‐101: A novel and green strategy for preparation of host–guest catalysts
Authors: Boroujeni Mahmoud Borjian , Hashemzadeh Alireza , Shaabani Ahmad , Amini Mostafa M. 
Published: January 2017

A novel strategy is developed to encapsulate metallophthalocyanines (MPcs, M = Cu, Ni and Co) into MIL‐101 to give MPcs@MIL‐101 via in situ synthesis of MPcs from component fragments in 1‐butyl‐3‐methylimidazolium bromide as an ionic liquid. This strategy overcomes some drawbacks of existing methods for encapsulation of MPcs into metal–organic frameworks. The chemical and structural properties of MPcs@MIL‐101 were determined using scanning electron microscopy, powder X‐ray diffraction, and Fourier transformation infrared and flame atomic absorption spectroscopies. The results showed that CuPc@MIL‐101, which was used as a ‘ship‐in‐a‐bottle’ catalyst, demonstrates excellent catalytic performance in the oxidative amidation of aldehydes with amine salts. It is confirmed that CuPc@MIL‐101 can be reused up to five times without significant loss of its activity.
Viscoelastic rheology in the melting and crystallization domain: Application to polypropylene copolymers
Authors: Aris‐Brosou Margaux , Vincent Michel , Agassant Jean‐François , Billon Noëlle 
Published: January 2017

ABSTRACTThe purpose of this article was to study the relationship between the rheological properties and the crystallization or melting of two polypropylene‐based copolymers used in the welding of the coating of offshore pipelines. The materials microstructure was studied via X‐ray diffraction, scanning electron microscopy, and optical microscopy. Differential scanning calorimetry was used to determine the crystallization and melting properties at different cooling and heating rates. Dynamic rheological analysis was used to define the rheological properties in the molten and in the transition zone from the molten to solid state and inversely. Both experiments (DSC and rheology) were performed under non‐isothermal conditions to allow complete accessibility to the transition zone. Crystallization and melting are both complex processes in which coexist amorphous and crystalline phases in the sample. A correlation between the rheological properties and crystallization was proposed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44690.
A traditional aboriginal condiment as an antioxidant agent in the development of biodegradable active packaging
Authors: López de Dicastillo Carol , Bruna Julio , Torres Alejandra , Alvarado Nancy , Guarda Abel , Galotto María José 
Published: January 2017

ABSTRACTIn this study, antioxidant food‐packaging materials were developed by the incorporation of merkén, an aboriginal Chilean spice, into a biodegradable polymer matrix, poly(lactic acid). Antioxidant activity assays and the phenolic content of merkén showed interesting results compared to other condiments, such as oregano and parsley. Active materials with merkén at 3 and 5 wt % were successfully obtained by extrusion. Chromatographic analysis revealed the chemical composition of merkén, and its active material was based on interesting flavonoids and organic acids, such as catechin, myricetin, and gallic and ellagic acids. Scanning electron micrographs showed that the merkén particles accumulated in aggregates; this resulted in an increase in the permeability values and a reduction in the crystallinity and mechanical properties of the polymer matrix. Nevertheless, these materials presented interesting antioxidant activities as radical scavengers on aqueous food simulants. The kinetics of release was dependent on the type of food and the nominal content of merkén in the films. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44692.
Photochemistry of 2,6‐di(4′‐azidobenzylidene)‐methylcyclohexanone in polymer matrices
Authors: Avadanei Mihaela 
Published: January 2017

ABSTRACT2,6‐Di(4′‐azidobenzylidene)‐methylcyclohexanone (ABC) was one of the most used photoinitiators in negative photoresists industry, rendering insolubility of the resist films at short UV exposure times (several minutes). Although the photodecomposition of aromatic azides is very well established, the peculiarities of the irradiation medium impose specific reaction pathways for arylnitrenes. In this study, photoreactions of arylnitrenes resulted from ABC photolysis were applied in the photoinitiated crosslinking of 1,2‐polybutadiene (1,2‐PB), under soft monochromatic UV irradiation (365 nm). To elucidate the crosslinking mechanism, studies on a model compound were performed. 3‐Methyl‐1‐butene was chosen to simulate the monomeric unit of 1,2‐PB. As a support in photoproducts identifying and with the purpose of a deeper investigation of the ABC photochemistry alone, ABC was photolysed in a rigid matrix of poly(methyl methacrylate). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44694.
Antioxidation and mechanism of phosphites including the free phenolic hydroxyl group in polypropylene
Authors: Meng Xin , Jiang Zewen , Xin Zhong , Chen Weijie , Sheng Yan , Wu Chushi 
Published: January 2017

ABSTRACTInhibiting the degradation of polypropylene (PP) in melt processing and usage is an important issue in the plastic industry. It is becoming more and more urgent to increase the antioxidation of phosphites alone while maintaining the water resistance. In this study, one phosphite antioxidant, named bis‐2,2′‐methyl‐4,6‐di‐tert‐butylphenyl phosphite (BM46TBPP), which contains a water‐resistant inner ring and a free phenolic hydroxyl group together, was synthesized. Then, antioxidation in PP was characterized with multiple extrusions and oxidation induction times (OITs). Finally, the hydrogen‐donating ability of this antioxidant was tested with 2,2‐diphenyl‐1‐picrylhydrazyl radical colorimetry to explain the antioxidation mechanism. The results show that the phosphite BM46TBPP displays better antioxidation than tris(2,4‐di‐tert‐butylphenyl) phosphite (Irgafos 168) in melt processing and OIT testing. Furthermore, the priority of this antioxidant was more obvious when it was used in the presence of oxygen, so the antioxidant even made the PP stabilized by it alone show a longer OIT value than the PP stabilized by the complex system including Irgafos 168 and 2,4‐di‐tert‐butylphenol because there was a free phenolic hydroxyl group in the BM46TBPP antioxidant molecule and the hydroxyl group made the antioxidant show intermolecular synergistic antioxidation through hydrogen donation to radicals. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44696.
Correlation of the polymer hydrophilicity and membrane fabrication process on the properties of asymmetric membranes in a vapor‐induced phase‐inversion process
Authors: Zhu Jianhua , Zhang Qifeng , Zheng Jifu , Hou Shuhua , Zhang Suobo , Li Shenghai 
Published: January 2017

ABSTRACTIn this study, we sought a better understanding of how the hydrophilicity of a polymer affects the morphology and performance of membranes. Three types of polymer with different hydrophilicity solution systems were considered: poly(aryl ether ketone) bearing a hydroxyl group (PEK–OH‐100) with N,N‐dimethylformamide (DMF); poly(aryl ether ketone) bearing a 50% fraction hydroxyl group with DMF, and cardo poly(aryl ether ketone) with DMF. These systems were used to investigate the evolution of the morphology and variation in performance versus a change in the hydrophilicity of the polymer. In addition, the fundamental thermodynamic influence of the solution systems on the phase‐inversion process was investigated by cloud‐point measurement and Hansen solubility parameter theory to determine the role of polymer hydrophilicity on the stability of the polymer solution in humid surroundings. The performance of the membranes was tested via testing of the pure water flux, porosity, and rejection of bovine serum albumin (BSA) with respect to variations in the polymer hydrophilicity, evaporation time, relative humidity, and molecular weight of the polymer. The resulting optimal membrane exhibited a flux of 329.3 L m−2 h−1 and a 99.3% rejection of BSA at a relative humidity of 90% and an evaporation time of 3 s. The hydrophilic PEK–OH‐100 membranes have promising applications in protein separation and the porous support of reverse‐osmosis membranes and so on. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44701.
The toughening behavior of PLLA and its asymmetric PLLA/PDLA blends with lower optical purity
Authors: Guo Yanmei , Shao Jun , Hou Haoqing 
Published: January 2017

ABSTRACTLinear poly(d‐lactide) (PDLA) with various molecular weights is synthesized and incorporated into commercial poly(l‐lactide) (PLLA) with different optical purities. And then, the crystallization, mechanical and thermal properties of the PLLA and PLLA/PDLA cast films are investigated. In the PLLA and PDLA/PLLA specimens with lower optical purity, few homochiral crystallites (HC) form in all the specimens and only a small amount of PLA stereocomplex crystallites (SC) are observed in the blends. The elongation at break of all the specimens is extraordinary high, >300%. Dynamic mechanical analyses indicate that the destruction temperature increases at first, and then depresses as enlarging the molecular weight of PDLA in these blends. For the PLLA and PLLA/PDLA with higher optical purity, more content of HC develops in neat PLLA, and both SC and HC produce in the PLLA/PDLA specimens. However, the strains of neat specimens and binary blends are much lower than that of specimens with lower optical purity. The specimens with higher optical purity exhibit higher destruction temperatures and lower loss factors. The high content of crystals (SC and HC) would act as the physical cross‐linking points and provide a key factor to impede the deformation of neat PLLA and binary blends during stretching, which should result in the fragile behavior of the PLLA and PLLA/PDLA blends with higher optical purity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44730.
Elaboration of performance of tea dust–polypropylene composites
Authors: Rathod Yogita , Bari Pravin , Hansora D. P. , Mishra Satyendra 
Published: January 2017

ABSTRACTIn this research work, dynamic, mechanical, and thermophysical properties of untreated and 5, 7, and 10 wt % styrene treated tea dust (TD):polypropylene (PP) composites prepared by injection‐molding machine were elaborated. There were distinctive and significant improvement observed in mechanical properties (tensile strength, tensile modulus, and elongation at break), physical analysis (water swelling), dynamic mechanical properties (storage modulus, loss modulus, and tan δ), and thermal behavior and surface morphological properties of styrene treated TD:PP (40:60) composites as compared to that of untreated one. The tensile strength (from 7.00 to 9.95 MPa), tensile modulus (from 350 to 715 MPa), storage modulus (from 8500 to ∼10,500 MPa), and loss modulus (from ∼150 to ∼200 MPa) increased on 10 wt % styrene treatment of TD over the untreated TD:PP (40:60) composites. The styrene treated TD:PP (40:60) composites behaved as more elastic than their pure counterpart. Styrene treated TD:PP (40:60) composites were more thermally more stable (85 °C difference) as compared to virgin PP. Overall, this research also indicates the use of TD waste. An improvement in dispersion of styrene treated TD particles in PP was also observed in the preparation of the PP composites due to good compatibility of styrene with PP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44750.
Removal of Cd2+ ions from aqueous solution using cassava starch–based superabsorbent polymers
Authors: Bai Wenbo , Fan Liren , Zhou Yang , Zhang Yin , Shi Jiyan , Lv Guohua , Wu Yongfeng , Liu Qi , Song Jiqing 
Published: January 2017

ABSTRACTA comprehensive feasibility study on the adsorption of Cd2+ ions by cassava starch–based superabsorbent polymers (CST‐SAPs) as the biosorbent was investigated as a function of adsorbent dosage, pH, initial concentration, contact time, and temperature. An orthogonal experiment and range analysis were applied to optimize the adsorption conditions. Adsorbent dosage and initial concentration were the most sensitive variables for adsorption capacity. The maximum adsorption value of Cd2+ ions was determined as 347.46 mg/g at pH 6.0, initial concentration of 200 mg/L, and contact temperature and time of 323 K and 6 h, respectively, with 0.1 g adsorbent dosage. The equilibrium data were well described by a Langmuir model, and the adsorption process was well fitted by pseudo‐second‐order kinetics. The Fourier transform infrared spectroscopy (FTIR) data confirmed that acrylic acid and acrylic amide grafted onto the cassava starch. The X‐ray diffraction and FTIR results for the Cd2+‐absorbed CST‐SAP (CST‐SAP‐Cd2+) samples showed that the CST‐SAP could effectively adsorb Cd2+ ions and that the characteristic groups were translocated by chelation. The scanning electron microscopy results for the CST‐SAP revealed that the surface of the polymer was rough, and the layered structure that was full of folds caused an enhanced specific surface; such conditions were beneficial to Cd2+ ion adsorption. It was concluded that the CST‐SAP was an excellent adsorbent for Cd2+ ion removal from aqueous solution. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44758.
A Multinational Arab Genome‐Wide Association Study Identifies New Genetic Associations for Rheumatoid Arthritis
Authors: Saxena Richa , Plenge Robert M. , Bjonnes Andrew C. , Dashti Hassan S. , Okada Yukinori , Gad El Haq Wessam , Hammoudeh Mohammed , Al Emadi Samar , Masri Basel K. , Halabi Hussein , Badsha Humeira , Uthman Imad W. , Margolin Lauren , Gupta Namrata , Mahfoud Ziyad R. , Kapiri Marianthi , Dargham Soha R. , Aranki Grace , Kazkaz Layla A. , Arayssi Thurayya 
Published: January 2017

ObjectiveGenetic factors underlying susceptibility to rheumatoid arthritis (RA) in Arab populations are largely unknown. This genome‐wide association study (GWAS) was undertaken to explore the generalizability of previously reported RA loci to Arab subjects and to discover new Arab‐specific genetic loci.MethodsThe Genetics of Rheumatoid Arthritis in Some Arab States Study was designed to examine the genetics and clinical features of RA patients from Jordan, the Kingdom of Saudi Arabia, Lebanon, Qatar, and the United Arab Emirates. In total, >7 million single‐nucleotide polymorphisms (SNPs) were tested for association with RA overall and with seropositive or seronegative RA in 511 RA cases and 352 healthy controls. In addition, replication of 15 signals was attempted in 283 RA cases and 221 healthy controls. A genetic risk score of 68 known RA SNPs was also examined in this study population.ResultsThree loci (HLA region, intergenic 5q13, and 17p13 at SMTNL2/GGT6) reached genome‐wide significance in the analyses of association with RA and with seropositive RA, and for all 3 loci, evidence of independent replication was demonstrated. Consistent with the findings in European and East Asian populations, the association of RA with HLA–DRB1 amino acid position 11 conferred the strongest effect (P = 4.8 × 10−16), and a weighted genetic risk score of previously associated RA loci was found to be associated with RA (P = 3.41 × 10−5) and with seropositive RA (P = 1.48 × 10−6) in this population. In addition, 2 novel associations specific to Arab populations were found at the 5q13 and 17p13 loci.ConclusionThis first RA GWAS in Arab populations confirms that established HLA‐region and known RA risk alleles contribute strongly to the risk and severity of disease in some Arab groups, suggesting that the genetic architecture of RA is similar across ethnic groups. Moreover, this study identified 2 novel RA risk loci in Arabs, offering further population‐specific insights into the pathophysiology of RA.