bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the effect of pressure on viscosity at high shear rates by using an injection molding machine
Authors: Volpe Valentina , Pantani Roberto
Published: May 2017

The effect of pressure on rheological behavior of polymer melts is surely a significant phenomenon for polymer processing, and its determination has been the object of several studies which highlighted the difficulties in performing accurate measurements. Even more important is the determination of this effect at very high shear rates, which cannot easily be obtained by conventional rheometers. In this work, a slit rheometer was located at the nozzle of the injection molding machine to obtain rheological measurements by means of two pressure transducers. Pressure values were analyzed by an original method to evaluate the pressure coefficient and the viscosity at zero pressure. The zero pressure viscosity aligned with independent rheological measurements obtained in previous works. The effect of pressure on viscosity was described by means of a parameter whose values resulted to be in line with those obtained in previous works, although the highest shear rates explored in this work were at least one order of magnitude larger. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45277.
Graphene‐based molecularly imprinted polymer for separation and pre‐concentration of trace polycyclic aromatic hydrocarbons in environmental water samples
Authors: Kibechu Rose Waithiegeni , Sampath Srinivasan , Mamba Bhekie Brilliance , Msagati Titus Alfred Makudali
Published: May 2017

A composite of reduced graphene oxide and pyrene‐imprinted polymer was synthesized and employed as a solid phase for extraction of five selected polycyclic aromatic hydrocarbons (PAHs) from water samples. Gas chromatography‐time of flight/mass spectrometry was employed in the analysis of the extracts. The composite was prepared by a free radical polymerization of methacrylic acid and 4‐vinylpyridine as monomers and ethylene glycol dimethacrylate as a crosslinker. The adsorption studies were carried out through batch binding studies. The binding capacity for the imprinted and non‐imprinted composite was 101.83 and 68.21 µg g−1, respectively. The adsorption followed the pseudo 2nd order and well fitted the Langmuir isotherm. Mean recoveries ranging from 73% to 105.4% for both spiked deionized water and environmental water samples were obtained when the imprinted composites were employed in solid phase extraction of the PAHs. The composites could be re‐used for five times without a significant loss in recoveries. The proposed method was employed for the analysis of spiked environmental water samples and did not show significant changes in the recoveries showing there were no matrix interferences. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45300.
Alkyl amine functional dextran macromonomer‐based thin film composite loose nanofiltration membranes for separation of charged and neutral solutes
Authors: Trivedi Jaladhi S. , Bera Anupam , Jewrajka Suresh K.
Published: May 2017

Thin film composite (TFC) nanofiltration membranes with defined porous structure of the separation layer are desirable for the concentration of neutral solute and separation of salts from a mixture. Herein, we report the formation of TFC membranes composed of polyamide (PA) separation layer by the interfacial polymerization between new dextran‐butyl amine (Dex‐NH2) macromonomer and trimesoyl chloride on polysulfone support membrane. The membranes prepared with 1%–1.5% (wt/vol) of Dex‐NH2 exhibited water permeance of 110–116 L m−2 h−1 MPa−1 with 62%–71% rejection of Na2SO4 and 12%–14% rejection of MgCl2. The membranes also showed about 91% rejection of poly(ethylene glycol) of molecular weight 2000 g/mol and about 11% rejection of NaCl. A decrease in permeance and ions selectivity was observed with increasing concentration of Dex‐NH2. The dextran chains attached to the PA network restrict the diffusion of Dex‐NH2 toward the interfacial zone and thereby assist the formation of porous and thin PA layer compared to that when free amine (alkyl diamine) was used. These membranes are applicable for the separation of small molecular weight neutral solutes from mixture containing monovalent salts. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45301.
Thermosensitive polymeric micelles based on the triblock copolymer poly(d,l‐lactide)‐b‐poly(N‐isopropyl acrylamide)‐b‐poly(d,l‐lactide) for controllable drug delivery
Authors: Li Peng , Zhang Zhenfang , Su Zhiqiang , Wei Gang
Published: May 2017

A thermosensitive amphiphilic triblock copolymer, poly(d,l‐lactide) (PLA)‐b‐poly(N‐isopropyl acrylamide) (PNIPAAM)‐b‐PLA, was synthesized by the ring‐opening polymerization of d,l‐lactide; the reaction was initiated from a dihydroxy‐terminated poly(N‐isopropyl acrylamide) homopolymer (HO‐PNIPAAM‐OH) created by radical polymerization. The molecular structure, thermosensitive characteristics, and micellization behavior of the obtained triblock copolymer were characterized with Fourier transform infrared spectroscopy, 1H‐NMR, gel permeation chromatography, dynamic light scattering, and transmission electron microscopy. The obtained results indicate that the composition of PLA‐b‐PNIPAAM‐b‐PLA was in good agreement with what was preconceived. This copolymer could self‐assemble into spherical core–shell micelles (ca. 75–80 nm) in aqueous solution and exhibited a phase‐transition temperature around 26 °C. Furthermore, the drug‐delivery properties of the PLA‐b‐PNIPAAM‐b‐PLA micelles were investigated. The drug‐release test indicated that the synthesized PLA‐b‐PNIPAAM‐b‐PLA micelles could be used as nanocarriers of the anticancer drug adriamycin (ADR) to effectively control the release of the drug. The drug‐delivery properties of PLA‐b‐PNIPAAM‐b‐PLA showed obvious thermosensitive characteristics, and the release time of ADR could be extended to 50 h. This represents a significant improvement from previous PNIPAAM‐based drug‐delivery systems. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45304.
Texts as actions: Requests in online chats between reference librarians and library patrons
Authors: Zemel Alan
Published: May 2017

Virtual reference services provide opportunities for library patrons to produce requests of reference librarians through quasi‐synchronous computer‐mediated exchanges in which requests and deliverables are produced as online textual objects. Text postings only become the actions they perform, such as an information request or deliverable, through the recipient's work of reading. Text postings thus are designed for their recipients and are built in ways that instruct particular readings. In this paper, I show that patron requests are interactional achievements co‐constituted by librarians and patrons through the exchange of text postings that are designed to be seen as requests. The Reference and User Services Association offers guidelines for online interactions between librarians and patrons. However, such guidelines provide only general recommendations by which librarians may overcome difficulties in identifying the specific information needs of patrons. I examine actual chat logs of virtual reference interactions and describe how librarians engage with patrons to co‐construct actionable requests to specify and fulfill patron information needs. Conversation analytic methods are used to identify the way texts are produced to instruct recipients in the ways they are to be read and how these texts serve, through reading's work, as an analysis of the actions prior texts perform.
Metabolic profiling of quercetin in rats using ultra‐performance liquid chromatography/quadrupole‐time‐of‐flight mass spectrometry
Authors: Wu Ming‐jiang , Wu Xiao‐lei , Zhang De‐qin , Qiu Feng , Ding Li‐qin , Ma Hao‐ling , Chen Xin‐ze
Published: May 2017

Quercetin, a kind of major flavonoid found in many traditional chinese medicines, is an effective substance for treatments such as lowering blood lipids. However, the studies on quercetin have been mainly focused on its pharmacological effect; the treatment of diseases on a material basis, particularly the metabolites derived from quercetin in vivo, has not been evaluated. In this study, we determined the levels, distributions and types of quercetin's metabolites in plasma, urine, feces and bile of rats after a single oral administration of quercetin at a dose of 80 mg/kg, using ultra‐performance liquid chromatography/quadrupole‐time‐of‐flight mass spectrometry (UPLC‐Q‐TOF/MS). A total of 36 metabolites of quercetin were identified, including 11 metabolites in plasma, 34 metabolites in urine, 12 metabolites in feces and 21 metabolites in bile. The results showed that phase I metabolites were reduction metabolites and phase II metabolites mainly included glucuronidation, sulfation and methylation metabolites. These results provide important information on the metabolism of quercetin, which will be helpful for its further development and utilization.
Associations between ABO blood groups and pancreatic ductal adenocarcinoma: influence on resection status and survival
Authors: El Jellas Khadija , Hoem Dag , Hagen Kristin G , Kalvenes May Britt , Aziz Sura , Steine Solrun J , Immervoll Heike , Johansson Stefan , Molven Anders
Published: May 2017

Both serology‐based and genetic studies have reported an association between pancreatic cancer risk and ABO blood groups. We have investigated this relationship in a cohort of pancreatic cancer patients from Western Norway (n = 237) and two control materials (healthy blood donors, n = 379; unselected hospitalized patients, n = 6149). When comparing patient and blood donor ABO allele frequencies, we found only the A1 allele to be associated with significantly higher risk for pancreatic ductal adenocarcinoma (PDAC) (23.8% vs. 17.9%; OR = 1.43, P = 0.018). Analyzing phenotypes, blood group A was more frequent among PDAC cases than blood donors (50.8% vs. 40.6%; OR = 1.51, P = 0.021), an enrichment fully explained by the A1 subgroup. Blood group O frequency was lower in cases than in blood donors (33.8% vs. 42.7%; OR = 0.69, P = 0.039). This lower frequency was confirmed when cases were compared to hospitalized patients (33.8% vs. 42.9%; OR = 0.68, P = 0.012). Results for blood group B varied according to which control cohort was used for comparison. When patients were classified according to surgical treatment, the enrichment of blood group A was most prominent among unresected cases (54.0%), who also had the lowest prevalence of O (28.7%). There was a statistically significant better survival (P = 0.04) for blood group O cases than non‐O cases among unresected but not among resected patients. Secretor status did not show an association with PDAC or survival. Our study demonstrates that pancreatic cancer risk is influenced by ABO status, in particular blood groups O and A1, and that this association may reflect also in tumor resectability and survival.
Lipid and Phenolic Constituents from Seeds of Hypericum perforatum L. and Hypericum tetrapterum Fr. and their Antioxidant Activity
Authors: Heinrich Miriam , Lorenz Peter , Daniels Rolf , Stintzing Florian C. , Kammerer Dietmar R.
Published: May 2017

Seeds of Hypericum perforatum and H. tetrapterum were extracted with dichloromethane and methanol and investigated by chromatographic and mass spectrometric methods. Both species yielded a fatty oil fraction amounting to 30.5% and 18.0% of the seed weight, respectively. Linoleic acid (C18:2n‐6) was shown to be the predominant fatty acid constituent. Moreover, xanthone derivatives, i.e. tetrahydroxyxanthones (THX), xanthone‐glycosides and xanthone‐sulfonates, were assigned in methanolic extracts. For structure elucidation, one representative xanthone, namely 1,3,6,7‐THX, was synthesized and analyzed via HPLC‐DAD/MSn and GC/MS. Total THX contents were quantitated applying a validated HPLC‐DAD method, resulting in 1.25 g/kg (H. perforatum) and 0.27 g/kg (H. tetrapterum), respectively. Moreover, the free radical scavenging capacity of the methanol extracts was tested using the DPPH antioxidant assay. Both, H. perforatum (IC50 = 8.7 mg/l) and 1,3,6,7‐THX (IC50 = 3.0 mg/l), exhibited good DPPH free radical scavenging activity compared to Trolox (IC50 = 6.6 mg/l).
Acetazolamide Inhibits the Level of Tyrosinase and Melanin: An Enzyme Kinetic, In Vitro, In Vivo, and In Silico Studies
Authors: Abbas Qamar , Raza Hussain , Hassan Mubashir , Phull Abdul Rehman , Kim Song Ja , Seo Sung‐Yum
Published: May 2017

Melanin is the major factor that determines skin color and protects from ultraviolet radiation. In present study we evaluated the anti‐melanogenesis effect of acetazolamide (ACZ) using four different approaches: enzyme kinetic, in vitro, in vivo and in silico. ACZ demonstrated significant inhibitory activity (IC50 7.895 ± 0.24 μm) against tyrosinase as compared to the standard drug kojic acid (IC50 16.84 ± 0.64 μm) and kinetic analyses showed that ACZ is a non‐competitive inhibitor without cytotoxic effect. In in vitro experiments, A375 human melanoma cells were treated with 20 or 40 μm of ACZ with or without 50 μm of l‐DOPA. Western blot results showed that ACZ significantly (P < 0.05) decreased the expression level of tyrosinase at 40 μm. Zebrafish embryos were treated with 10, 20 or 40 μm of ACZ and of positive control kojic acid. At 72 h of treatment with ACZ and kojic acid, ACZ significantly (P < 0.001) decreased the embryos pigmentation to 40.8% of untreated embryos at the dose of 40 μm of ACZ while kojic acid decreased only 25.0% of pigmentation at the same dose of kojic acid. In silico docking were performed against tyrosinase using PyRx tool. Docking studies suggested that His244, Asn260 and His85 are the major interacting residues in the binding site of the protein. In conclusion, our results suggest that ACZ is a good candidate for the inhibition of melanin and it could be used as a lead for developing the drugs for hyperpigmentary disorders and skin whitening.
Porous Aromatic Framework as an Efficient Metal‐Free Electro‐catalyst for Non‐enzymatic H2O2 Sensing
Authors: Yuan Rongrong , Gu Yue , Ren Hao , Liu Jia , Zhu Guangshan
Published: May 2017

A porous aromatic framework (referred as PAF‐39) based on tetrakis(4‐(9H‐carbazol‐9‐yl)phenyl)methane has been designed and synthesized by oxidative coupling polymerization. PAF‐39 exhibits high surface area and high heat of adsorption (Qst) of CO2. Especially, the PAF material was applied for non‐enzymatic H2O2 sensing.
Two‐Dimensional Covalent Organic Frameworks for Optoelectronics and Energy Storage
Authors: Mandal Amal Kumar , Mahmood Javeed , Baek Jong‐Beom
Published: May 2017

Synthetic polymers with branched macromolecules and outstanding functional‐group tolerance exhibit diverse and useful properties that influence most aspects of modern life. Extending polymerization strategies to two dimensions (2D) allows precise integration of building units into extended structures with periodic skeletons and ordered nanopores. The construction principle of these frameworks is to direct the topological evolution in a predictable manner with controlled geometry, dimensions and structural periodicity. This unique designable feature of 2D covalent organic frameworks (2D‐COFs) with versatile properties makes them an emerging material platform, with great interest for areas such as gas storage, separation, catalysis and optoelectronics. In this Focus Review, we discuss the recent progress in 2D‐COFs as optoelectronic materials with an emphasis on their semiconducting, energy‐conversion and energy‐storage properties.
Performance of the Ishihara, D‐15, and City University colour vision test as a function of intraocular straylight
Authors: Zlatkova Margarita , Robinson Elizabeth , Beirne Raymond O.
Published: May 2017

Three colour vision tests, the Ishihara test, the City University Test (CUT), and the D‐15 test were studied as a function of induced intraocular straylight, using a commercially available light‐scattering filter. Thirty young individuals (aged 17‐28 years) with no ocular abnormalities and normal colour vision participated in the study. Intraocular straylight was estimated in all individuals using a psychophysical compensation method with the C‐Quant straylight meter, with and without the light‐scattering filter which caused an increase in intraocular straylight typical of that found for cataract. Under normal viewing conditions all the subjects passed each of the 3 tests with no errors. When viewing the Ishihara test plates through the filter, 10 out of the 30 observers made at least 1 error. Three subjects also made errors on the desaturated CUT test plates, but all subjects still passed the D‐15 test with the filter. The errors in the Ishihara test correlated with the amount of intraocular straylight, as measured with the C‐Quant. This study indicates that interpretation of the Ishihara test in a clinical environment will be made more difficult in individuals with higher levels of straylight.
A generic parallel pattern interface for stream and data processing
Authors: del Rio Astorga David , Dolz Manuel F. , Fernández Javier , García J. Daniel
Published: May 2017

Current parallel programming frameworks aid developers to a great extent in implementing applications that exploit parallel hardware resources. Nevertheless, developers require additional expertise to properly use and tune them to operate efficiently on specific parallel platforms. On the other hand, porting applications between different parallel programming models and platforms is not straightforward and demands considerable efforts and specific knowledge. Apart from that, the lack of high‐level parallel pattern abstractions, in those frameworks, further increases the complexity in developing parallel applications. To pave the way in this direction, this paper proposes GRPPI, a generic and reusable parallel pattern interface for both stream processing and data‐intensive C++ applications. GRPPI accommodates a layer between developers and existing parallel programming frameworks targeting multi‐core processors, such as C++ threads, OpenMP and Intel TBB, and accelerators, as CUDA Thrust. Furthermore, thanks to its high‐level C++ application programming interface and pattern composability features, GRPPI allows users to easily expose parallelism via standalone patterns or patterns compositions matching in sequential applications. We evaluate this interface using an image processing use case and demonstrate its benefits from the usability, flexibility, and performance points of view. Furthermore, we analyze the impact of using stream and data pattern compositions on CPUs, GPUs and heterogeneous configurations.
A Free‐Radical Pathway to Hydrogenated Phenanthrene in Molecular Clouds—Low Temperature Growth of Polycyclic Aromatic Hydrocarbons
Authors: Thomas Aaron M. , Lucas Michael , Yang Tao , Kaiser Ralf I. , Fuentes Luis , Belisario‐Lara Daniel , Mebel Alexander M.
Published: May 2017

The hydrogen‐abstraction/acetylene‐addition mechanism has been fundamental to unravelling the synthesis of polycyclic aromatic hydrocarbons (PAHs) detected in combustion flames and carbonaceous meteorites like Orgueil and Murchison. However, the fundamental reaction pathways accounting for the synthesis of complex PAHs, such as the tricyclic anthracene and phenanthrene along with their dihydrogenated counterparts, remain elusive to date. By investigating the hitherto unknown chemistry of the 1‐naphthyl radical with 1,3‐butadiene, we reveal a facile barrierless synthesis of dihydrophenanthrene adaptable to low temperatures. These aryl‐type radical additions to conjugated hydrocarbons via resonantly stabilized free‐radical intermediates defy conventional wisdom that PAH growth is predominantly a high‐temperature phenomenon and thus may represent an overlooked path to PAHs as complex as coronene and corannulene in cold regions of the interstellar medium like in the Taurus Molecular Cloud.
Growth of the complex borates YxRySc2+z(BO3)4 (R = Nd, Pr, x + y + z = 2) with huntite structure
Authors: Kokh A. E. , Kuznetsov A. B. , Pestryakov E. V. , Maillard A. , Maillard R. , Jobard C. , Kononova N. G. , Shevchenko V. S. , Kragzhda A. A. , Uralbekov B. , Kokh K. A.
Published: May 2017

Bulk crystals of new huntite type borates were grown by TSSG method using eutectic LiBO2–LiF as a flux. Chemical composition, X‐ray diffraction, optical absorption and fluorescence spectra of the grown samples were studied.
A study of microstructure and optical absorption properties of Cu(In,Ga,Al)Se2 powders
Authors: Ma Qiang , Zhang WeiJia , Ma Denghao , Jiang Zhaoyi , Ma Xiaobo , Fan Zhiqiang
Published: May 2017

CuInxGayAl1‐x‐ySe2 powders were prepared using a solvothermal reaction technique in ethylenediamine at 290°C for 20 hours. The microstructure and optical absorption properties of the powders were investigated by XRD, SEM, TEM, XPS and UV‐Vis‐NIR spectra. The results indicated that the Al atom was successfully incorporated into the CuInxGa1‐xSe2 lattices, and Al doping had a significant effect on the microstructure, especially at the (112) crystal orientation. It was found that the peak of (112) shifted obviously to higher 2θ values with the increasing aluminum content. Transmission electron microscope observation revealed that the size of the CuInxGayAl1‐x‐ySe2 nanoparticles could be adjusted by varying the stoichiometric ratio of the In, Ga and Al, and the proper Al incorporation could reduce the density of the stacking faults and nanotwins in the CuInxGayAl1‐x‐ySe2 materials. XRD analysis indicated that the Al incorporation could effectively substitute In and Ga atoms. Finally, the band gap was obtained by UV‐Vis‐NIR spectra, and the results implied that the optical absorption value decreased and optical band gap increased significantly with the incorporation of Al, and it is close to the optimal band gap (1.37 eV) of solar cells when the stoichiometric ratio of the Al was between 0.2 and 0.3.
High‐Efficiency Perovskite Solar Cell Based on Poly(3‐Hexylthiophene): Influence of Molecular Weight and Mesoscopic Scaffold Layer
Authors: Nia Narges Yaghoobi , Matteocci Fabio , Cina Lucio , Di Carlo Aldo
Published: May 2017

Here, we investigated the effect of the molecular weight (MW) of poly 3‐hexylthiophene (P3HT) hole‐transport material on the performance of perovskite solar cells (PSCs). We found that by increasing the MW the photovoltaic performances of the cells are enhanced leading to an improvement of the overall efficiency. P3HT‐based PSCs with a MW of 124 kDa can achieve an overall average efficiency of 16.2 %, double with respect to the ones with a MW of 44 kDa. Opposite to spiro‐OMeTAD‐based PSCs, the photovoltaic parameters of the P3HT‐based devices are enhanced by increasing the mesoporous TiO2 layer thickness from 250 to 500 nm. Moreover, for a titania scaffold layer thickness of 500 nm, the efficiency of P3HT‐based PSCs with high MW is larger than the spiro‐OMeTAD based PSCs with the same scaffold layer thickness. Recombination reactions of the devices were also investigated by voltage decay and electrochemical impedance spectroscopy. We found that the relationship between P3HT MW and cell performance is related to the reduction of charge recombination and to the increase of the P3HT light absorption by increasing the MW.
Design and deployment of a smart system for data gathering in aquaculture tanks using wireless sensor networks
Authors: Parra Lorena , Sendra Sandra , Lloret Jaime , Rodrigues Joel J.P.C.
Published: May 2017

The design of monitoring systems for marine areas has increased in the last years. One of the many advantages of wireless sensor networks is the quick process in data acquisition. The information from sensors can be processed, stored, and transmitted using protocols efficiently designed to energy saving and establishing the fastest routes. The processing and storing of data can be very useful for taking intelligent decisions for improving the water quality. The monitoring of water exchange in aquaculture tanks is very important to monitor the fish welfare. Thus, this paper presents the design, deployment, and test of a smart data gathering system for monitoring several parameters in aquaculture tanks using a wireless sensor network. The system based on a server is able to request and collect data from several nodes and store them in a database. This information can be postprocessed to take efficient decisions. The paper also presents the design of a conductivity sensor and a level sensor. These sensors are installed in several aquaculture tanks. The system was implemented using Flyport modules. Finally, the data gathering system was tested in terms of consumed bandwidth and the delay Transmission Control Protocol (TCP) packets delivering data from the sensors.
Ferrocene‐Based, Potentially D,C,D‐Coordinating (D = O, S), Pincer‐Type Proligands and Their Organotin Derivatives
Authors: Nayyar Bastian , Koop Stefan , Lutter Michael , Jurkschat Klaus
Published: May 2017

Metalation of 1,3‐diiodoferrocene provided ferrocene‐based D,C,D‐containing (D = O, S) pincer‐type ligands [(η5‐Cp)Fe(η5‐C5H3‐1,3‐{P(D)R2}2)] (1: D = O, R = OiPr; 2: D = O, R = OPh; 3: D = S, R = Ph). The corresponding organotin derivatives [(η5‐Cp)Fe(η5‐C5H2‐1‐SnPh3‐2,5‐{P(O)(OiPr)2}2)] (4), [(η5‐Cp)Fe(η5‐C5H2‐1‐SnPh2I‐2,5‐{P(O)(OiPr)2}2)] (5), and [(η5‐Cp)Fe(η5‐C5H2‐1‐SnMe3‐2,4‐{P(S)Ph2}2)] (6) are reported as well. The compounds were characterized by elemental analysis, 1H, 13C, 31P, 119Sn NMR and IR spectroscopy, ESI mass spectrometry, and single‐crystal X‐ray diffraction (3 and 4).
On the Role of PTB7‐Th:[70]PCBM Blend Concentration in ortho‐Xylene on Polymer Solar‐Cell Performance
Authors: Salamandra Luigi , La Notte Luca , Paronesso Giorgia , Susanna Gianpaolo , Cinà Lucio , Polino Giuseppina , Mattiello Leonardo , Catini Alexandro , Di Natale Corrado , Martinelli Eugenio , Di Carlo Aldo , Brunetti Francesca , Brown Thomas M. , Reale Andrea
Published: May 2017

The use of low‐band‐gap polymers as donors is a new approach to realize high‐efficiency polymer solar cells. Among the low bandgap polymers, poly{4,8‐bis[5‐(2‐ethylhexyl)thiophen‐2‐yl]benzo[1,2‐b;4,5‐b′]dithiophene‐2,6‐diyl‐alt‐[4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene]‐2‐carboxylate‐2‐6‐diyl} (PTB7‐Th) is one of the most promising candidates, thanks to the possibility of exploiting deposition protocols (technique, solvent, concentration) from the most‐known poly{[4,8‐bis(2‐ethylhexyloxy)benzo(1,2‐b:4,5‐b′)dithiophene]‐2,6‐diyl‐alt‐[4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene]‐2‐carboxylate‐2‐6‐diyl} (PTB7) and the fact that it shows a power conversion efficiency (PCE) exceeding 10 %. In this paper, we focus on the role of the ink concentration for film deposition and the formation of the active layer. The effect of the solid content (PTB7‐Th:[70]PCBM; [70]PCBM=[6,6]‐phenyl‐C71‐butyric acid methyl ester) in an ortho‐xylene‐based solution on the performance of the polymer solar cell was investigated. Further, a correlation between the solid content and the1,8‐diiodooctane additive in the ink formulation with respect to device performance was discussed. A remarkable PCE of 8.2 % was demonstrated.
Factors determining subsidence in urbanized floodplains: evidence from MT‐InSAR in Seville (southern Spain)
Authors: Ruiz‐Constán Ana , Ruiz‐Armenteros Antonio M. , Galindo‐Zaldívar Jesús , Lamas‐Fernández Francisco , Sousa Joaquim João , Sanz de Galdeano Carlos , Pedrera Antonio , Martos‐Rosillo Sergio , Caro Cuenca Miguel , Delgado J. Manuel , Hanssen Ramon F. , Gil Antonio J.
Published: May 2017

Major rivers have traditionally been linked with important human settlements throughout history. The growth of cities over recent river deposits makes necessary the use of multidisciplinary approaches to characterize the evolution of drainage networks in urbanized areas. Since under‐consolidated fluvial sediments are especially sensitive to compaction, their spatial distribution, thickness, and mechanical behavior must be studied. Here, we report on subsidence in the city of Seville (Southern Spain) between 2003 and 2010, through the analysis of the results obtained with the Multi‐Temporal InSAR (MT‐InSAR) technique. In addition, the temporal evolution of the subsidence is correlated with the rainfall, the river water column and the piezometric level. Finally, we characterize the geotechnical parameters of the fluvial sediments and calculate the theoretical settlement in the most representative sectors. Deformation maps clearly indicate that the spatial extent of subsidence is controlled by the distribution of under‐consolidated fine‐grained fluvial sediments at heights comprised in the range of river level variation. This is clearly evident at the western margin of the river and the surroundings of its tributaries, and differs from rainfall results as consequence of the anthropic regulation of the river. On the other hand, this influence is not detected at the eastern margin due to the shallow presence of coarse‐grain consolidated sediments of different terrace levels. The derived results prove valuable for implementing urban planning strategies, and the InSAR technique can therefore be considered as a complementary tool to help unravel the subsidence tendency of cities located over under‐consolidated fluvial deposits. Copyright © 2017 John Wiley & Sons, Ltd.
Standardized toxicity testing may underestimate ecotoxicity: Environmentally relevant food rations increase the toxicity of silver nanoparticles to Daphnia
Authors: Stevenson Louise M. , Krattenmaker Katherine E. , Johnson Erica , Bowers Alexandra J. , Adeleye Adeyemi S. , McCauley Edward , Nisbet Roger M.
Published: May 2017

Daphnia in the natural environment experience fluctuations in algal food supply, with periods when algal populations bloom and seasons when Daphnia have very little algal food. Standardized chronic toxicity tests, used for ecological risk assessment, dictate that Daphnia must be fed up to 400 times more food than they would experience in the natural environment (outside of algal blooms) for a toxicity test to be valid. This disconnect can lead to underestimating the toxicity of a contaminant. We followed the growth, reproduction, and survival of Daphnia exposed to 75 and 200 µg/L silver nanoparticles (AgNPs) at 4 food rations for up to 99 d and found that AgNP exposure at low, environmentally relevant food rations increased the toxicity of AgNPs. Exposure to AgNP at low food rations decreased the survival and/or reproduction of individuals, with potential consequences for Daphnia populations (based on calculated specific population growth rates). We also found tentative evidence that a sublethal concentration of AgNPs (75 µg/L) caused Daphnia to alter energy allocation away from reproduction and toward survival and growth. The present findings emphasize the need to consider resource availability, and not just exposure, in the environment when estimating the effect of a toxicant. Environ Toxicol Chem 2017;36:3008–3018. © 2017 SETAC
A collaborative key management scheme for distributed smart objects
Authors: Hendaoui Fatma , Eltaief Hamdi , Youssef Habib
Published: May 2017

Secure communication of Internet of Things (IoT) devices relies on cryptographic approaches whose robustness is based on the security of encryption keys. For instance, an adequate key management scheme must be used to properly manage the used keys. Designing an efficient and robust key management scheme for the connected devices is a challenging task. Reported key management schemes suffer from several deficiencies such as the single point of failure and the non–trade‐off between scalability, connectivity, and resiliency. This paper first reviews key management schemes in the context of the IoT. Then, we propose a collaborative lightweight key management scheme that secures the keys during the life cycle of the embedded devices. Our proposal relies on the collaboration of the smart devices, where all the devices participate in the construction of the global key. Following the analytical and the comparative studies, we show that our proposal can be integrated in several communication protocols designated for embedded devices such as IEEE 802.15.4. Simulation results validate the analytical study and show that the proposed collaborative group key scheme exhibits superior performance when compared with two corresponding schemes reported in the literature.
Relation Between Ni Particle Shape Change and Ni Migration in Ni–YSZ Electrodes – a Hypothesis
Authors: Mogensen M. B. , Hauch A. , Sun X. , Chen M. , Tao Y. , Ebbesen S. D. , Hansen K. V. , Hendriksen P. V.
Published: May 2017

This paper deals with degradation mechanisms of Ni–YSZ electrodes for solid oxide cells, mainly solid oxide electrolysis cells (SOECs), but also to some extent solid oxide fuel cells (SOFCs). Analysis of literature data reveals that several apparently different and even in one case apparently contradicting degradation phenomena are a consequence of interplay between loss of contact between the Ni–YSZ (and Ni–Ni particles) in the active fine‐structured composite fuel electrode layer and migration of Ni via weakly oxidized Ni hydroxide species. A hypothesis that unravels the apparent contradiction and explains qualitatively the phenomena is presented, and as a side effect, light has been shed on a degradation phenomenon in solid oxide fuel cells (SOFCs) that has been observed during a decade.
Scale‐up of Solid Oxide Fuel Cells with Magnetron Sputtered Electrolyte
Authors: Solovyev A. A. , Lebedynskiy A. M. , Shipilova A. V. , Ionov I. V. , Smolyanskiy E. A. , Lauk A. L. , Remnev G. E. , Maslov A. S.
Published: May 2017

The possibility of fabricating large‐area solid oxide fuel cells (SOFC) with thin film electrolyte using a commercial physical vapor deposition technology is investigated. Yttria‐stabilized zirconia (YSZ)/gadolinium‐doped ceria (GDC) bilayer electrolyte is successfully deposited on a 10 × 5 cm2 commercial NiO/YSZ anode support by reactive magnetron sputtering. The microstructure of the fuel cells was studied by scanning electron microscopy. Current‐voltage characteristics of fuel cells at a temperature of 750°C and their power stability under electrical load were investigated. Single cells with La0.6Sr0.4Co0.2Fe0.8O3/ Gd0.1Ce0.9O1.95 (LSCF/GDC) cathode had an open cell voltage of 1.14 V and a maximum power density of 490 mW cm−2 at 750 °C using H2/N2 gas mixture as fuel and air as the oxidant. Three‐cell planar SOFC stack using 10 × 5 cm2 anode‐supported unit cells with power density of 450 mW cm−2 at a voltage of 0.7 V per cell has been assembled and tested.
Catalyst regeneration using CO2 as reactant through reverse‐Boudouard reaction with coke
Authors: Pereira Sérgio Castro , Ribeiro M. Filipa , Batalha Nuno , Pereira Marcelo Maciel
Published: May 2017

The possibility of CO2 recycling into standard refinery can largely mitigate greenhouse gas emissions. It was previously demonstrated that alumina modified by either potassium or lithium in the presence of vanadium was able to promote the reaction of CO2 with coke in the presence of O2 during the regeneration step of a spent catalyst. Herein, vanadium‐sodium and vanadium‐calcium on alumina were used to achieve that reaction. These catalysts showed slightly lower conversion compared to previously catalysts. However, regardless of the type of group I and II elements, all catalysts showed very similar apparent activation energy (Eaapp) for the coke oxidation with CO2 reaction (), i.e., in the range of 188–193 kJ.mol−1. In contrast without vanadium, Eaapp was in the range of 242–253 kJ.mol−1. Therefore, CO2 is activated in a site composed of V‐O‐(group I or II) in the coke proximity. Moreover, these results clearly support that vanadium plays the main role in the type of activation complex, independently of the group I and II metal used and most probably in the dissociative step of CO2. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.
White matter microstructure in athletes with a history of concussion: Comparing diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI)
Authors: Churchill Nathan W. , Caverzasi Eduardo , Graham Simon J. , Hutchison Michael G. , Schweizer Tom A.
Published: May 2017

Sport concussion is associated with disturbances in brain function in the absence of gross anatomical lesions, and may have long‐term health consequences. Diffusion‐weighted magnetic resonance imaging (MRI) methods provide a powerful tool for investigating alterations in white matter microstructure reflecting the long‐term effects of concussion. In a previous study, diffusion tensor imaging (DTI) showed that athletes with a history of concussion had elevated fractional anisotropy (FA) and reduced mean diffusivity (MD) parameters. To better understand these effects, this study compared DTI results to neurite orientation dispersion and density imaging (NODDI), which was used to estimate the intracellular volume fraction (VIC) and orientation dispersion index (ODI). Sixty‐eight (68) varsity athletes were recruited, including 37 without a history of concussion and 31 with concussion >6 months prior to imaging. Univariate analyses showed elevated FA and decreased MD for concussed athletes, along with increased VIC and reduced ODI, indicating greater neurite density and coherence of neurite orientation within white matter. Multivariate analyses also showed that for athletes with a history of concussion, white matter regions with increased FA had increased VIC and decreased ODI, with greater effects among athletes who were imaged a longer time since their last concussion. These findings enhance our understanding of the relationship between the biophysics of water diffusion and concussion neurobiology for young, healthy adults. Hum Brain Mapp 38:4201–4211, 2017. © 2017 Wiley Periodicals, Inc.
The implications of regional variations in rainfall for reconstructing rainfall patterns using tree rings
Authors: Haines Heather A. , Olley Jon M.
Published: May 2017

In Australia, multidecadal periods of floods and droughts have major economic consequences. Due to the short duration of Australian instrumental precipitation records, it is difficult to determine the patterns of these multidecadal periods. Proxy records can be used to create long‐term rainfall reconstructions for regions that are lacking instrumental data. However, the spatial extent over which single‐site proxy records can be applied is poorly understood. Southeast Queensland (SEQ) is an area where tree rings can be used to reconstruct long‐term rainfall patterns, but their regional representation is unknown. In this study, the spatial variability in rainfall across SEQ is investigated from 1908 to 2007 using 140 instrumental rainfall stations. Pearson correlation analysis between stations is used to create groups at the r = 0.80, 0.85, and 0.90 correlation levels, and then annual deviations from the mean are determined. These patterns indicate that rainfall is not uniform across SEQ but can be broken into 2 main spatially consistent groups. Each of these groups is broken down into several subgroups with higher correlation levels. Long‐term streamflow records are found to be correlated to rainfall patterns local to the streamflow stations, indicating that analysis of extreme events should consider spatial precipitation variability. Finally, the only currently available proxy rainfall reconstruction for the region, a 140‐year Toona ciliata tree ring width record from Lamington National Park, is compared to rainfall groups at different correlation levels across all of SEQ. The correlation between the reconstruction and the rainfall station groupings is best for the groups within which the tree‐ring record is spatially located, and this correlation improves as rainfall group correlation increases. Correlation is nearly nonexistent for groupings located at a distance from the tree‐ring site. These results demonstrate the importance of assessing the spatial variability of precipitation so that the spatial applicability of proxy records can be assessed.
Preschoolers' cognitive and emotional self‐regulation in pretend play: Relations with executive functions and quality of play
Authors: Slot Pauline Louise , Mulder Hanna , Verhagen Josje , Leseman Paul P.M.
Published: May 2017

The preschool period is marked by rapid growth of children's self‐regulation and related executive functions. Self‐regulation is considered an important aspect of school readiness and is related to academic and social–emotional outcomes in childhood. Pretend play, as part of the early childhood curriculum, is hypothesized to support self‐regulation. An important question concerns whether self‐regulation should be considered an individual ability or, partly, a situated skill that is influenced by aspects of the classroom context. The aims of this study were to investigate the degree to which 3‐year‐olds showed cognitive and emotional self‐regulation in a naturalistic play setting and to examine how test‐based measures of children's cool and hot executive functions and the quality of their pretend play contributed to this observed self‐regulation. The results indicated that 3‐year‐olds showed aspects of cognitive and emotional self‐regulation. Cool executive functions appeared significantly related to emotional self‐regulation, whereas hot executive functions were not significantly related to cognitive or emotional self‐regulation. The quality of pretend play was strongly associated with cognitive self‐regulation and, to a lesser extent, emotional self‐regulation. The findings of this study suggest that both preschoolers' cool executive functions and the quality of play contributed to their self‐regulation skills in naturalistic settings.

Highlights

Preschoolers' cognitive and emotional self‐regulation in a naturalistic play setting are two interrelated but separate constructs.

Children's cognitive executive functions predict observed emotional self‐regulation during pretend play.

The quality of pretend play is strongly associated with children's cognitive self‐regulation and, to a lesser extent, emotional self‐regulation.
Osteoporosis in Crisis: It's Time to Focus on Fracture
Authors: Binkley Neil , Blank Robert D , Leslie William D , Lewiecki E Michael , Eisman John A , Bilezikian John P
Published: May 2017

A crisis in osteoporosis treatment exists; the majority of those who sustain fracture do not receive treatment to reduce future fracture risk. This crisis presents an opportunity to focus the field from osteoporosis to fracture, the outcome of consequence. Proposed here is a change in focus suggesting that 1) attempts to define the level of trauma leading to fracture are counterproductive and that all fractures in older adults merit consideration of evaluation and 2) bone loss is not the entire problem but rather part of a broader syndrome including osteoporosis, sarcopenia, and other factors leading to fracture. With this approach, all fractures in older adults should be evaluated for potential lifestyle, non-pharmacological, and pharmacological interventions that could be implemented to reduce the risk of fracture recurrence. © 2017 American Society for Bone and Mineral Research.
Poor peripheral blood stem cell mobilization affects long‐term outcomes in multiple myeloma patients undergoing autologous stem cell transplantation
Authors: Moreb Jan S. , Byrne Michael , Shugarman Ilicia , Zou Fei , Xiong Sican , May William S. , Norkin Maxim , Hiemenz John , Brown Randall , Cogle Christopher , Wingard John R. , Hsu Jack W.
Published: May 2017

Background

Peripheral blood stem cell (PBSC) mobilization is routinely undertaken prior to autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM). A number of studies have identified risk factors for poor PBSC mobilization, however, little data exists to correlate mobilization with disease‐specific outcomes in this patient population. Prospective work in MM has demonstrated similar outcomes in a homogenous patient population.

Methods

In this single institution analysis, we retrospectively studied the impact of poor PBSC mobilization on progression free survival (PFS) and OS in MM patients undergoing PBSC mobilization. Poor mobilizers are defined as patients that collected < 4 × 106 CD34+ cells/kg over maximum of 5 apheresis days, or those that required ≥2 mobilization cycles to achieve this target.

Results

We confirm that poor PBSC mobilization is significantly associated with a shortened PFS (P = .0012) and OS (P = .0005) compared with good mobilizers. Our univariate analysis also shows that independent risk factors for poor mobilization include male gender, higher ideal body weight, and a greater median number of lines of chemotherapy prior to PBSC mobilization. However, by multivariate analysis, only number of prior lines of chemotherapy remains significantly predictive of poor mobilization (Odds ratio 1.857, P = .0095). The use of high‐dose G‐CSF (> 10 mcg/kg/day) and/or plerixafor can significantly improve mobilization and ASCT chances in this population.

Discussion

These data indicate that poor mobilization can be predictable and is associated with more aggressive disease biology and worse outcomes, warranting intensive post‐ASCT management.
Combined Angiography and Late Gadolinium Enhancement Acquisition to Improve Assessment of Pulmonary Vein Isolation for Atrial Fibrillation
Authors: Lam Adrian , Okene Erica , Parikh Ankit , Zhong Xiaodong , Tejada Thor , Hoskins Michael , Lloyd Michael , Oshinski John N.
Published: May 2017

Purpose

To develop a Shared K‐space (SharK) magnetic resonance imaging (MRI) sequence that combines angiographic and late gadolinium enhancement (LGE) acquisitions to improve atrial wall segmentation and scar identification, and to develop a novel visualization method that quantifies scar encirclement of pulmonary veins postablation treatment for atrial fibrillation.

Materials and Methods

A SharK sequence was developed and used at 3T to image the left atrium in 11 patients postcryoballoon ablation. The effects of sharing k‐space between the angiographic and LGE acquisitions on the accuracy of scar were assessed. The left atrial wall was segmented and points about each pulmonary vein (PV) ostia were projected onto a bullseye to quantitatively compare PV encirclement. The parameters used to quantify encirclement were varied to perform a sensitivity analysis.

Results

Compared to using a complete set of k‐space, total atrial scar differences were significant only when sharing >75% k‐space (P = 0.014), and 90% sensitivity and specificity for identifying scar was achieved when sharing 50% k‐space. In patients, the right PVs showed more intersubject variance in encirclement compared to the left PVs. A 100° anteroinferior portion of the left PVs was always encircled, while the superior segments of both right PVs was ablated in only 6/11 patients.

Conclusion

A SharK sequence was developed to combine angiographic and LGE imaging for atrial wall segmentation and scar identification. The PV bullseye quantifies and localizes encirclement about the PVs. The left PVs showed a higher amount of scar encirclement and less variability compared to the right PVs.

Level of Evidence: 2

Technical Efficacy: Stage 1

J. Magn. Reson. Imaging 2018;47:477–486.