bluuebunny/crossref_metadata_2025 huggingface dataset:
Custo de uso de keynes como instrumento gerenciamento de recursos naturais
Authors: Junqueira Lustosa Maria Cecilia
Published: April 2018

O debate sobre crescimento econômico e meio ambiente está relacionado com o gerenciamento de estoques dos recursos naturais. A necessidade de um instrumento analítico que trate a questão de maneira intertemporal, numa economia monetária e com incertezas, faz resgatar o conceito de custo de uso elaborado por J. M. Keynes. Os recursos naturais, tratados como estoques de capital, estão sujeitos a decisões de torná-los líquidos ou de conservá-los ilíquidos, a depender da avaliação ex-ante da opção de utilizá-los na produção atual ou no futuro. Nesse sentido, o custo de uso é uma variável expectacional e sofre grande influência da taxa de desconto utilizada para atualizar os valores esperados dos rendimentos futuros, se a taxa de desconto social ou a taxa de desconto privada. Evidencia-se o conflito entre o desejo da sociedade de preservar o recurso natural e a maior lucratividade do ponto de vista do cálculo maximizador de lucros individuais.
Crise fiscal, dívida e juros altos: desafios para a macroeconomia brasileira
Authors: Azevedo José Sergio Gabrielli
Published: April 2018

O artigo busca destacar algumas tentativas de flexibilização do tripé macroeconômico de 2003-2015, com ênfase nas questões fiscais e sua relação com a taxa de juros e taxas de cambio. A dificuldade de implementar uma política alternativa é contrastada com a avaliação de que as politicas de ajuste aumentam a desigualdade e revertem as tendências de redução da pobreza, como mostram as experiências internacionais. As dificuldades de cortes das despesas de custeio levam a politicas recessivas, com queda de crescimento de produto, menor receita fiscal, principalmente quando combinada com politicas de juros elevados, que aumentam os desembolsos nominais do setor público. Por fim, a conclusão do artigo é que o conflito distributivo latente na economia brasileira se torna o principal componente do equilíbrio das contas públicas na escolha dos grupos sociais que carregarão o maior peso do ajuste.
Duas evidências da incompleta estabilização macroeconômica brasileira
Authors: Silva Alexandre Manoel Ângelo , Ranciaro Neto Adhemar
Published: April 2018

Este trabalho possui dois importantes objetivos. Primeiro, esquematizar os mecanismos que levam à ausência de completude da estabilização macroeconômica brasileira iniciada em 1994. Segundo, ao fazer uso de dados oficiais do Tesouro Nacional e daqueles que consideram a contabilidade criativa utilizada nos últimos anos, prover duas evidências dessa incompletude: i) desequilíbrio fiscal do Governo Federal por meio de análise de rating; ii) ausência de sustentabilidade da política fiscal do Governo Federal por meio do modelo de Bohn (1998).
Supporting child witnesses during identification lineups: Exploring the effectiveness of registered intermediaries
Authors: Wilcock Rachel , Crane Laura , Hobson Zoe , Nash Gilly , Kirke‐Smith Mimi , Henry Lucy A.
Published: April 2018

Performance at identification lineup was assessed in eighty‐five 6‐ to 11‐year‐old typically developing children. Children viewed a live staged event involving 2 male actors, and were asked to identify the perpetrators from 2 separate lineups (one perpetrator‐present lineup and one perpetrator‐absent lineup). Half the children took part in lineups adapted by a registered intermediary (an impartial, trained professional who facilitates understanding and communication between vulnerable witnesses and members of the justice system), and half took part in “best‐practice” lineups, according to the current guidance for eyewitness identification in England and Wales. Children receiving assistance from a registered intermediary (relative to children who received best‐practice lineups) were more accurate in their identifications for perpetrator‐present lineups, and there was some evidence that they were also more accurate for perpetrator‐absent lineups. This provides the first empirical evidence for the effectiveness of registered intermediary support during identification lineups.
Experimental Study on Tunable Electromagnetic Shielding by Microlattice Materials with Organized Microstructures
Authors: Cai Xiaobing , Hu Mingjun , Zhang Dongxing , Hu Gengkai , Yang Jun
Published: April 2018

Porous metal materials are widely used for preventing electromagnetic interference, control of heat conduction and impact absorbing. However, a limitation associated with porous metals is that their irregular and non‐uniformal microstructures make their functions non‐desirably tunable. In this report, the authors propose a microlattice material with precisely controlled microstructures for electromagnetic (EM) shielding. An effective medium model taking into account of the EM stimulated surface current of the metal wires is developed to characterize the EM shielding effect of the microlattice metal. In addition, a compact and integrated measuring device is constructed by using a 3D printing method for experimental verification. The theoretical predictions agree well with the experimental measurement. The influence of the geometrical parameters of the microlattice metals on EM shielding effect is also studied. The theoretical model and the compact measuring system provide robust and efficient tools for the design of EM shielding materials.
Re‐Use of Marble Stone Powders in Producing Unsaturated Polyester Composites
Authors: Doan Thi Thu Loan , Brodowsky Hanna M. , Gohs Uwe , Mäder Edith
Published: April 2018

The main goal of this study is to evaluate the potential of waste stone powders as filler in composite materials with a matrix of unsaturated polyester. These wastes are generated in the form of stone fragments and stone‐cutting sludge. Ground marble wastes are thoroughly characterized with the aim to use them as fillers: Mineralogical and chemical composition, particle size distribution, and morphology of these waste stone powders are investigated. Unsaturated polyester resin composites with the different stone powder fillers are prepared. The influence of powder type on the composites’ mechanical properties (tensile, bending, impact, and hardness characteristics), water resistance, thermal stability as well as surface fracture morphology of composites are studied. The moduli of the composites increase by 100%, the hardness of the composites may be improved by 80% upon loading with the “waste” filler, leading to an economical material and helping to reduce waste.
A Bubble‐Derived Strategy to Prepare Multiple Graphene‐Based Porous Materials
Authors: Zhang Rujing , Hu Ruirui , Li Xinming , Zhen Zhen , Xu Zhenhua , Li Na , He Limin , Zhu Hongwei
Published: April 2018

Graphene‐based porous structures have triggered tremendous attention due to their promising application in many fields. Recent progress has yielded structures with stochastic porous networks, which limit their controllability and potential performance. It still remains a big challenge for the scalable production to integrate the 2D building block into engineered porous architectures in multidimensions. Here, a versatile technique based on soft bubble templating and fixation by freezing is described to fabricate 3D bubble‐derived graphene foams (BGFs) and 2D bubble‐derived graphene porous membranes (BGPMs). These light‐weight novel structures are carefully tuned. The BGFs show high adsorption capabilities for organic solvents and good recovery in structural deformation. Furthermore, applications of BGFs and BGPMs in strain sensors for wearable devices are discussed, working as a combined system which can both detect the compressive and tensile deformation. This technique can be extended to assemble other nanomaterials as building blocks into macroscopic configurations.
Flexible Near‐Infrared Plastic Phototransistors with Conjugated Polymer Gate‐Sensing Layers
Authors: Han Hyemi , Lee Chulyeon , Kim Hwajeong , Kim Youngkyoo
Published: April 2018

Flexible near‐infrared (NIR) light‐sensing detectors are strongly required in the fast‐growing flexible electronics era, because they can serve as a vision system like eyes in various innovative applications including humanoid robots. Recently, keen interest has been paid to organic phototransistors due to their unique signal amplification and active matrix driving features over organic photodiodes. However, conventional NIR‐sensing organic phototransistors suffer from the limited use of organic materials because the channel layers play a dual role in both charge transport and sensing so that organic semiconducting materials with reasonably high charge mobility can be applied only. Here, it is demonstrated that a conjugated polymer, poly[{2,5‐bis‐(2‐ethylhexyl)‐3,6‐bis‐(thien‐2‐yl)‐pyrrolo[3,4‐c]pyrrole‐1,4‐diyl}‐co‐{2,2′‐(2,1,3‐benzothiadiazole)]‐5,5′‐diyl}] (PEHTPPD‐BT), which exhibits no transistor performance as a channel layer, can stably detect a NIR light (up to 1000 nm) as a gate‐sensing layer (GSL) when it is placed between gate‐insulating layers and gate electrodes. The flexible array (10 × 10) detectors with the PEHTPPD‐BT GSLs could effectively sense NIR light without visible light interference by applying visible light cut films.
Site‐Controlled Single‐Photon Emitters Fabricated by Near‐Field Illumination
Authors: Biccari Francesco , Boschetti Alice , Pettinari Giorgio , La China Federico , Gurioli Massimo , Intonti Francesca , Vinattieri Anna , Sharma MayankShekhar , Capizzi Mario , Gerardino Annamaria , Businaro Luca , Hopkinson Mark , Polimeni Antonio , Felici Marco
Published: April 2018

Many of the most advanced applications of semiconductor quantum dots (QDs) in quantum information technology require a fine control of the QDs' position and confinement potential, which cannot be achieved with conventional growth techniques. Here, a novel and versatile approach for the fabrication of site‐controlled QDs is presented. Hydrogen incorporation in GaAsN results in the formation of N–2H and N–2H–H complexes, which neutralize all the effects of N on GaAs, including the N‐induced large reduction of the bandgap energy. Starting from a fully hydrogenated GaAs/GaAsN:H/GaAs quantum well, the NH bonds located within the light spot generated by a scanning near‐field optical microscope tip are broken, thus obtaining site‐controlled GaAsN QDs surrounded by a barrier of GaAsN:H (laterally) and GaAs (above and below). By adjusting the laser power density and exposure time, the optical properties of the QDs can be finely controlled and optimized, tuning the quantum confinement energy over more than 100 meV and resulting in the observation of single‐photon emission from both the exciton and biexciton recombinations. This novel fabrication technique reaches a position accuracy <100 nm and it can easily be applied to the realization of more complex nanostructures.
Few‐Layer GeAs Field‐Effect Transistors and Infrared Photodetectors
Authors: Guo Jian , Liu Yuan , Ma Yue , Zhu Enbo , Lee Shannon , Lu Zixuan , Zhao Zipeng , Xu Changhao , Lee Sung‐Joon , Wu Hao , Kovnir Kirill , Huang Yu , Duan Xiangfeng
Published: April 2018

The family of 2D semiconductors (2DSCs) has grown rapidly since the first isolation of graphene. The emergence of each 2DSC material brings considerable excitement for its unique electrical, optical, and mechanical properties, which are often highly distinct from their 3D counterparts. To date, studies of 2DSC are majorly focused on group IV (e.g., graphene, silicene), group V (e.g., phosphorene), or group VIB compounds (transition metal dichalcogenides, TMD), and have inspired considerable effort in searching for novel 2DSCs. Here, the first electrical characterization of group IV–V compounds is presented by investigating few‐layer GeAs field‐effect transistors. With back‐gate device geometry, p‐type behaviors are observed at room temperature. Importantly, the hole carrier mobility is found to approach 100 cm2 V−1 s−1 with ON–OFF ratio over 105, comparable well with state‐of‐the‐art TMD devices. With the unique crystal structure the few‐layer GeAs show highly anisotropic optical and electronic properties (anisotropic mobility ratio of 4.8). Furthermore, GeAs based transistor shows prominent and rapid photoresponse to 1.6 µm radiation with a photoresponsivity of 6 A W−1 and a rise and fall time of ≈3 ms. This study of group IV–V 2DSC materials greatly expands the 2D family, and can enable new opportunities in functional electronics and optoelectronics based on 2DSCs.
A Novel Nanocomposite with Superior Antibacterial Activity: A Silver‐Based Metal Organic Framework Embellished with Graphene Oxide
Authors: Firouzjaei Mostafa Dadashi , Shamsabadi Ahmad Arabi , Sharifian Gh. Mohammad , Rahimpour Ahmad , Soroush Masoud
Published: April 2018

Silver‐based nanomaterials have attracted considerable attention due to their antimicrobial activities. In this work, a silver (Ag)‐based metal organic framework (Ag‐MOF) is embellished with graphene‐oxide (GO), leading to the fabrication of a novel Ag‐based nanocomposite (GO‐Ag‐MOF) whose biocidal activity is higher than those of Ag‐MOF and GO nanomaterials. The nanocomposite is characterized using X‐ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscope, Fourier transform infrared spectra, ultraviolet−visible absorption spectra, X‐ray powder diffraction, dynamic light scattering, and nitrogen gas adsorption/desorption. The characterization shows that the Ag‐MOF nanoparticles are uniformly dispersed on the GO nanosheets surfaces without any agglomeration. Toxicities of GO‐Ag‐MOF, Ag‐MOF, and GO are assessed against the Gram‐negative bacteria, Escherichia coli and the Gram‐positive bacteria, Bacillus subtilis using the growth curve, fluorescence imaging, and flow cytometry methods. GO‐Ag‐MOF shows an outstanding antibacterial activity (higher than those of the Ag‐MOF and GO alone). The interaction of GO‐Ag‐MOF and Ag‐MOF with the bacteria leads to the extirpation of 95 and 85% of live bacteria cells, respectively. This study indicates that GO‐Ag‐MOF is a promising antibacterial nanocomposite, especially for biomedical applications.
Constructing Hierarchical Heterostructured Mn3O4/Zn2SnO4 Materials for Efficient Gas Sensing Reaction
Authors: Zhou Tingting , Liu Xiupeng , Zhang Rui , Wang Lili , Zhang Tong
Published: April 2018

Hybrid 1D nanomaterials with hierarchical structure have received a great deal of attention as sensing materials for gas sensors due to their high surface area, excellent catalytic performance, and robust structure. Novel Zn2SnO4 nanorod‐decorated Mn3O4 nanowire 1D nanostructures are prepared by a two‐step hydrothermal method and subsequent heat treatment for application in gas sensors. The branch‐like Mn3O4/Zn2SnO4 composite‐based sensor exhibits high sensitivity and excellent selectivity for the detection of acetone gas. Importantly, the sensitivity of acetone‐gas sensor can be improved by optimizing the content of Zn2SnO4 nanorods on the surface of Mn3O4 nanowires. As a result, such a 1D–1D branch‐like Mn3O4/Zn2SnO4 hierarchical structure with effective p–n heterojunction and large specific surface area would display excellent electron transport property, which determines if the material is capable of recognizing target gases, thus enabling the sensor to achieve high sensitivity.
Strategy for Enhancing Interfacial Effect of Bifunctional Electrocatalyst: Infiltration of Cobalt Nanooxide on Perovskite
Authors: Kim Seona , Kwon Ohhun , Kim Changmin , Gwon Ohhun , Jeong Hu Young , Kim Ka‐Hyun , Shin Jeeyoung , Kim Guntae
Published: April 2018

Recently, hybrid catalysts are a critical issue to realize electrocatalysts having competitive price and effective bifunctional activity for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In the case of hybrid catalysts, synergistic effect is observed through electronic and structural reconstructions at the interface between dissimilar oxides, which provides the improved catalytic activity for ORR and OER. Herein, the Co3O4 deposited Nd0.5Sr0.5CoO3−δ (NSC) catalyst is designed to achieve the strain and ligand effect considered as rationale for synergistic effect. A well‐designed bifunctional hybrid catalyst (Opt‐NSC@Co3O4) is prepared through a useful infiltration technique by tuning the wettability of the precursor solution and the concentration of the Co3O4. Through systematic analysis and re‐design, both the onset potential and the limiting current density for ORR and OER are significantly improved with unique microstructure fabricated by the infiltration technique. Opt‐NSC@Co3O4 shows outstanding cell performance and excellent stability during 60 h with the discharge–charge voltage gap of 0.5 V for a hybrid Li‐air battery. The enhanced electrochemical performance suggests that the derived hybrid catalysts fabricated by the advanced infiltration technique could be promising materials for environmentally benign energy‐related applications.
The Effect of Thickness‐Tunable ZrO2 Shell on Enhancing the Tunneling Magnetoresistance of Fe3O4 Supraparticles
Authors: Mi Shu , Xie Yong , Li Yuanyuan , Liu Rui , Liu Xiaoduo , Smalyukh Ivan I. , Chen Ziyu
Published: April 2018

The core–shell Fe3O4@ZrO2 nanoparticles with controllable shell thickness and core dimensions are synthesized using solvothermal approaches. The introduction of the insulator ZrO2 shell allows realizing the enhancement of tunneling magnetoresistance (TMR) effect of the functional nanomaterials. The influences of temperature, magnetic field, and shell thickness on the TMR are explored. With the shell thickness ≈3 nm TMR ratio of 10% is obtained, which improves the MR compared to the pure Fe3O4 counterpart of 5.7%. Furthermore, the MR is increased first and then decreases with increase of the shell thickness, which suggests that the addition of insulated shell‐layer promotes the electron tunneling among the supraparticles and thereby increases the MR. The fault‐cutting data indicate that the tunneling mechanism occurs mainly through the magnetic‐insulator interfaces rather than the interior nanoparticle interfaces. In addition, the MR with different core‐size presents a monotonic increase with decrease of the size of core.
Giant Auxetic Behaviour in Engineered Graphene
Authors: Grima Joseph N. , Grech Michael C. , Grima‐Cornish James N. , Gatt Ruben , Attard Daphne
Published: April 2018

Graphene monolayers engineered to adopt a corrugated conformation are found to exhibit very pronounced lateral expansion characteristics upon uniaxial stretching in specific directions, i.e. giant negative Poisson's ratio (auxeticity). Such anomalous properties are manifested in‐plane and may be controlled through the shape and amplitude of the wave‐like pattern of the corrugation, which in the case of graphene may be controlled through the introduction of patterned ‘defects’. This confirms that auxeticity via corrugation can be achieved even at the nanoscale, as demonstrated here for graphene with patterned ‘defects’, suggesting that this mechanism should be operational at different scales of structures, thus providing a new blueprint for the design or manufacture of auxetic materials and metamaterials which can have tailor‐made giant negative Poisson's ratio properties.
Fast Sodium‐Ion Conductivity in Supertetrahedral Phosphidosilicates
Authors: Haffner Arthur , Hatz Anna‐Katharina , Moudrakovski Igor , Lotsch Bettina V. , Johrendt Dirk
Published: April 2018

Fast sodium‐ion conductors are key components of Na‐based all‐solid‐state batteries which hold promise for large‐scale storage of electrical power. We report the synthesis, crystal‐structure determination, and Na+‐ion conductivities of six new Na‐ion conductors, the phosphidosilicates Na19Si13P25, Na23Si19P33, Na23Si28P45, Na23Si37P57, LT‐NaSi2P3 and HT‐NaSi2P3, based entirely on earth‐abundant elements. They have SiP4 tetrahedra assembled interpenetrating networks of T3 to T5 supertetrahedral clusters and can be hierarchically assigned to sphalerite‐ or diamond‐type structures. 23Na solid‐state NMR spectra and geometrical pathway analysis show Na+‐ion mobility between the supertetrahedral cluster networks. Electrochemical impedance spectroscopy shows Na+‐ion conductivities up to σ (Na+)=4×10−4 S cm−1. The conductivities increase with the size of the supertetrahedral clusters through dilution of Na+‐ions as the charge density of the anionic networks decreases.
Synthesis of a novel, multifunctional inorganic curing agent and its effect on the flame‐retardant and mechanical properties of intrinsically flame retardant epoxy resin
Authors: Guo Xing , Wang Hongsen , Ma Delong , He Jinnan , Lei Ziqiang
Published: April 2018

Traditional curing agents have only a single property, while traditional synthetic organic flame‐retardant hardeners often show poor tolerance to oxidants, strongly acidic or alkaline reagents, and organic solvents and have toxicity problems. Here, a novel and multifunctional flame‐retardant curing agent of the inorganic substrate multifunctional curing agent of the inorganic substrate (FCIN) was proposed first and successfully prepared, and then an intrinsically flame‐retardant epoxy resin (EP) was prepared by covalently incorporating FCIN nanoparticles (FCINs) into the EP. The curing behavior of the FCINs was investigated, showing that FCIN/EP expresses a higher global activation energy than tetraethylenepentamine (TEPA)/EP and that the FCINs had strong interfacial adhesion to the EP matrix. Additionally, the FCINs were well dispersed and provided a remarkable improvement in mechanical and flame‐retardant properties of the intrinsically flame‐retardant EP. With the incorporation of 9 wt % FCINs into the EP, dramatic enhancements in the strength, modulus under bending, and toughness (∼36%, ∼109%, and ∼586%, respectively) were observed, along with 85.2%, 46.4%, 98.3%, and 77.26% decreases in the peak heat release rate, total heat release, smoke production rate peak, and total smoke production, respectively, with respect to that of TEPA/EP. The mechanisms of its flame‐retardant, smoke‐suppression, and failure behaviors were investigated. The development of this unconventional, multifunctional flame‐retardant curing agent based on an inorganic substrate showed promise for enabling the preparation of a variety of new high‐performance materials (such as intrinsically flame‐retardant EP and functional modified polyesters). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46410.
Micellization of a di‐block copolymer in ethylene glycol and its utilization for suspension of carbonaceous nanostructures
Authors: Cohen Neta , Ziv Efrat , Vasilyev Gleb , Convertine Anthony , Levi‐Kalisman Yael , Yerushalmi‐Rozen Rachel
Published: April 2018

Suspensions of carbonaceous nanoparticles (NPs) in ethylene glycol (EG) can be used as colloidal inks for additive manufacturing and nano‐fluids for heat‐transfer applications. While micellar solutions of surfactants are often used for suspension of the NPs in water, micellization of surfactants in EG is suppressed as compared to aqueous solutions and a well‐defined critical micellization concentration (CMC) is often not observed. Unlike the surfactants, a di‐block copolymer comprising a poly(ethylene glycol) monomethylether methacrylate (PEGMA) segment, 2‐(diethylaminoethyl) methacrylate (DEAEMA) and butyl methacrylate (BMA), poly(O950)‐b‐(DEAEMA‐co‐BMA) was found to assemble into spherical micelles in EG. Surface tension measurements show a well‐defined CMC that depends on the volume fraction of EG. Cryogenic transmission electron microscopy and dynamic light scattering show the presence of spherical micelles with a diameter that reduces with the volume fraction of EG. The micellar solutions were further used for suspending carbonaceous NPs of different geometry and characteristic dimensions: C60 fullerenes, multi‐walled carbon nanotubes, and nanodiamonds. The flow behavior of the suspensions exhibits a relatively low viscosity and mostly Newtonian behavior due to strong interaction between the NPs and the micelles. These suspensions may be used as colloidal inks for two‐dimensional and three‐dimensional printing. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46518.
Design, synthesis, biological evaluations, molecular docking, and in vivo studies of novel phthalimide analogs
Authors: Zahran Magdy A. H. , El‐Aarag Bishoy , Mehany Ahmed B. M. , Belal Amany , Younes Ali S.
Published: April 2018

A series of novel phthalimide analogs containing an indole or brominated indole moiety were synthesized and their antimicrobial activity was evaluated. Compound 8 showed a broad spectrum activity, revealing 53–67% of erythromycin activity on the tested bacteria and 60–70% of miconazole activity on the tested fungi. Anticancer activity was evaluated on the cell lines HepG2, MCF‐7, A549, H1299, and Caco2. The results revealed that the new phthalimide analog 8 has broad‐spectrum anticancer activity toward all the tested cancer cell lines, followed by compound 11, which showed good activity toward all the tested cell lines except for MCF‐7. The ability of the promising analogs 5, 8, and 11 to bind to topoisomerase II DNA gyrase was investigated. Caspase‐3 activation and Bcl‐2 assay of the best active derivatives 8, 11 in addition to compound 5 were evaluated. The antifibrotic activity was studied in an in vivo model and the histopathological studies revealed that treatment with the new compound 8 improved the fibrotic liver tissues to normality.
Flow dependent ensemble spread in seasonal forecasts of the boreal winter extratropics
Authors: MacLeod Dave , O'Reilly Chris , Palmer Tim , Weisheimer Antje
Published: April 2018

Flow‐dependent spread (FDS) is a desirable characteristic of probabilistic forecasts; ensemble spread should represent the expected forecast error. However this is difficult to estimate for seasonal hindcasts as they tend to have a relatively small sample size. Here we use a long (110 year) seasonal hindcast dataset to evaluate FDS in forecasts of boreal winter North Atlantic Oscillation (NAO) and Pacific North American pattern (PNA). A good FDS relationship is found for interannual variations in both the NAO and PNA, with mild underdispersion for negative NAO and PNA events and slight overdispersion for positive NAO. Decadal‐scale variability is seen in forecast errors but not in ensemble spread, which shows little variation on this timescale. Links between forecast errors and tropical heating anomalies are also investigated, though no strong links are found. However, a weak link between strong El Niño warming in the East Pacific and reduced PNA error is suggested.
Proposed dynamic error control techniques for QoS improvement of wireless 3D video transmission
Authors: El‐Shafai W. , El‐Rabaie S. , El‐Halawany M. M. , Abd El‐Samie Fathi E.
Published: April 2018

Error control techniques like error resilience (ER) and error concealment (EC) are efficient techniques to ameliorate the lost macroblocks (MBs) in the 3D video (3DV) communication system. In this paper, we propose efficient and adaptive hybrid ER‐EC algorithms for 3DV transmission over error‐prone wireless channels. At the encoder, adaptive preprocessing ER mechanisms are proposed through using the context adaptive variable length coding entropy, slice structured coding modes, and explicit flexible macroblock ordering mapping. They are used to assist the suggested EC techniques at the decoder to accurately reconstruct the erroneous MBs and frames. At the decoder, an efficient postprocessing EC technique with multiproposition methods is proposed to dynamically select the convenient EC hypothesis method based on the size of the lost MBs, the faulty view, and the frame type. It conceals the received erroneous MBs of intra‐encoded and inter‐encoded frames of the transmitted 3DV by exploiting the temporal, spatial, and inter‐view correlations among frames and views. To further improve the decoded 3DV quality, a weighted overlapping block motion and disparity compensation technique is used to reinforce the performance of the suggested ER‐EC techniques. Experimental results on various 3DV streams prove that the suggested techniques have considerably acceptable subjective and objective 3DV performance. They achieve an improved average peak signal‐to‐noise ratio gain by almost 2.85 dB compared to the conventional error control algorithms at a packet loss rate = 40%.
Maximizing the lifetime of energy‐constrained cooperative spectrum sensing sensor network
Authors: Shukry Suzan , Fahmy Yasmine
Published: April 2018

Adding the cognitive capability to wireless sensor networks allows the sensors to monitor the spectrum and identify the spectrum holes to operate in different frequencies according to the radio environment which result in better spectrum utilization. Spectrum sensing is a main component in any cognitive radio network. In this paper, we propose a new cooperative sensing scheme based on energy detection for cognitive sensor networks which is constrained by the energy limitation of the wireless sensor elements. The proposed scheme minimizes the sensing energy for individual sensor and carefully selects the suitable participant sensors in each cooperative sensing process. This results in maximizing the lifetime of energy‐constrained wireless sensor networks. The proposed scheme also takes into consideration the constraints on the detection accuracy. The simulation results show that the proposed scheme prolonged the lifetime of the cognitive network, makes efficient usage of available spectrum by secondary users, and satisfy the target detection performance.
Evaluation of antioxidant properties of lemon verbena (Lippia citriodora) essential oil and its capacity in sunflower oil stabilization during storage time
Authors: Farahmandfar Reza , Asnaashari Maryam , Pourshayegan Mehdi , Maghsoudi Sara , Moniri Hannaneh
Published: April 2018

In this study, lemon verbena essential oil as a natural antioxidant was used to increase the stability of sunflower oil, and stabilization effects in terms of storage conditions were compared with synthetic antioxidant (BHT). For this purpose, the antioxidant activity of the essential oil was determined by DPPH assay and β‐carotene bleaching method. Then, lemon verbena essential oil (0, 400, 800, and 1,600 ppm) was added to sunflower oil without synthetic antioxidant and stored at 60°C for 60 days. Results from different parameters (peroxide value, free fatty acid, iodine value, total polar compound, carbonyl value, conjugated dienes, and oxidative stability index) were in agreement with each other, suggesting that lemon verbena essential oil (1,600 ppm) could act better than BHT in inhibition of lipid oxidation in sunflower oil and can be used as predominant alternative of synthetic antioxidants.
An fMRI study of finger tapping in children and adults
Authors: Turesky Ted K. , Olulade Olumide A. , Luetje Megan M. , Eden Guinevere F.
Published: April 2018

Functional brain imaging studies have characterized the neural bases of voluntary movement for finger tapping in adults, but equivalent information for children is lacking. When contrasted to adults, one would expect children to have relatively greater activation, reflecting compensation for an underdeveloped motor system combined with less experience in the execution of voluntary movement. To test this hypothesis, we acquired functional magnetic resonance imaging (fMRI) data on 17 healthy right‐handed children (7.48 ± 0.66 years) and 15 adults (24.9 ± 2.9 years) while they performed an irregularly paced finger‐tapping task in response to a visual cue (left‐ and right‐hand examined separately). Whole‐brain within‐group analyses revealed that finger tapping in either age group and for either hand activated contralateral SM1, SMA, ipsilateral anterior cerebellum, and occipital cortices. We used an ANOVA factorial design to test for main effects of Age Group (children vs adults), Hand (left vs. right), and their interactions. For main effects of Age Group, children showed relatively greater activity in left SM1 (extending into bilateral SMA), and, surprisingly, adults exhibited relatively greater activity in right pre‐SMA/SMA (extending into left pre‐SMA/SMA), right lateral globus pallidus, left putamen, and right anterior cerebellum. The interaction of Age Group × Hand revealed that while both groups activated right SM1 during left finger tapping and exhibited signal decreases (i.e., below fixation baseline) during right finger tapping, both these responses were attenuated in children relative to adults. These data provide an important foundation by which to study children with motor disorders.
In vitro effect of graphene structures as an osteoinductive factor in bone tissue engineering: A systematic review
Authors: Mohammadrezaei Dorsa , Golzar Hossein , Rezai Rad Maryam , Omidi Meisam , Rashedi Hamid , Yazdian Fatemeh , Khojasteh Arash , Tayebi Lobat
Published: April 2018

Graphene and its derivatives have been well‐known as influential factors in differentiating stem/progenitor cells toward the osteoblastic lineage. However, there have been many controversies in the literature regarding the parameters effect on bone regeneration, including graphene concentration, size, type, dimension, hydrophilicity, functionalization, and composition. This study attempts to produce a comprehensive review regarding the given parameters and their effects on stimulating cell behaviors such as proliferation, viability, attachment and osteogenic differentiation. In this study, a systematic search of MEDLINE database was conducted for in vitro studies on the use of graphene and its derivatives for bone tissue engineering from January 2000 to February 2018, organized according to the PRISMA statement. According to reviewed articles, different graphene derivative, including graphene, graphene oxide (GO) and reduced graphene oxide (RGO) with mass ratio ≤1.5 wt % for all and concentration up to 50 μg/mL for graphene and GO, and 60 μg/mL for RGO, are considered to be safe for most cell types. However, these concentrations highly depend on the types of cells. It was discovered that graphene with lateral size less than 5 µm, along with GO and RGO with lateral dimension less than 1 µm decrease cell viability. In addition, the three‐dimensional structure of graphene can promote cell‐cell interaction, migration and proliferation. When graphene and its derivatives are incorporated with metals, polymers, and minerals, they frequently show promoted mechanical properties and bioactivity. Last, graphene and its derivatives have been found to increase the surface roughness and porosity, which can highly enhance cell adhesion and differentiation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2284‐2343, 2018.
High resolution photolithography for direct view active matrix organic light‐emitting diode augmented reality displays
Authors: Malinowski Paweł E. , Ke Tung‐Huei , Nakamura Atsushi , Liu Ya‐Han , Vander Velpen Dieter , Vandenplas Erwin , Papadopoulos Nikolas , Kronemeijer Auke Jisk , van der Steen Jan‐Laurens , Steudel Soeren , Kuo Che‐Cheng , Huang Yen‐Yu , Chen Yu‐Hsien , Yeh Ming‐Hua , Gelinck Gerwin , Heremans Paul
Published: April 2018

High‐resolution RGB organic light‐emitting diode frontplane is a key enabler for direct‐view transparent augmented reality displays. In this paper, we demonstrate 1250 ppi passive displays and semi‐transparent active displays. Organic light‐emitting diode photolithography can provide pixel density above 1000 ppi while keeping effective emission area high because of high aperture ratio. Patterns with 2 μm line pitch were successfully transferred to emission layers, indicating possible further pixel density scaling. Lifetime after patterning, key parameter enabling industrialization, is above 150 h (T90 at 1000 nit).
Almost minimizers for semilinear free boundary problems with variable coefficients
Authors: de Queiroz Olivaine S. , Tavares Leandro S.
Published: April 2018

We study regularity results for almost minimizers of the functional
urn:x-wiley:0025584X:media:mana201600103:mana201600103-math-0001where is a matrix with Hölder continuous coefficients. In the case we show that an almost minimizer belongs to , where the exponent η is related with the competition between the Hölder continuity of the matrix , the parameter of almost minimization and γ. In some sense, this regularity is optimal. As far as the case is concerned, our results show that an almost minimizer is locally in each phase and , improving in some sense a recent result of David & Toro.
Association rules method and big data: Evaluating frequent medication combinations associated with fractures in older adults
Authors: Nishtala Prasad S. , Chyou Te‐yuan , Held Fabian , Le Couteur David G. , Gnjidic Danijela
Published: April 2018

Background

The association rules method is a novel methodology to ascertain patterns of medication use and combinations associated with adverse drug events.

Objectives

The aim of this case‐crossover study was to apply the association rules method to ascertain medication combinations contributing to the risk of fractures in older adults.

Methods

A nationwide representative sample of New Zealanders aged ≥65 years was sourced from the pharmaceutical collection. The first‐time coded diagnosis of fracture was extracted from the National Minimum Dataset. Association rule method is a data mining technique that can be used to quickly traverse big datasets to identify a combination of items that co‐occur. The association rules method were applied to identify frequent 11 medication combinations in the case and the control periods (1‐14 days as hazard period, with 35‐day washout period), and the association of fractures with each frequent medication combination were tested by computing a matched odd ratio (OR) and its 95% CI.

Results

We identified a total of 72 184 individuals (mean age 81.5 years) from 2005 to 2014 with incident fracture and exposed to at least 1 medication of interest. The association rules method revealed codeine phosphate (aOR = 11.50, 95% CI, 7.09‐15.20, concomitantly with ibuprofen), zopiclone (aOR = 2.34, 95% CI, 1.49‐3.67, concomitantly with morphine) and quetiapine (OR = 1.95, 95% CI, 1.28‐2.98, concomitantly with zopiclone) were associated with fractures.

Conclusion

The association rules method identified medication exposure combinations containing psychotropic medications and codeine are frequently associated with fractures. This novel methodology applied to big data can be an important tool to ascertain medication combinations associated with adverse drug events.
Chemometric Strategies for Peak Detection and Profiling from Multidimensional Chromatography
Authors: Navarro‐Reig Meritxell , Bedia Carmen , Tauler Romà , Jaumot Joaquim
Published: April 2018

The increasing complexity of omics research has encouraged the development of new instrumental technologies able to deal with these challenging samples. In this way, the rise of multidimensional separations should be highlighted due to the massive amounts of information that provide with an enhanced analyte determination. Both proteomics and metabolomics benefit from this higher separation capacity achieved when different chromatographic dimensions are combined, either in LC or GC. However, this vast quantity of experimental information requires the application of chemometric data analysis strategies to retrieve this hidden knowledge, especially in the case of nontargeted studies. In this work, the most common chemometric tools and approaches for the analysis of this multidimensional chromatographic data are reviewed. First, different options for data preprocessing and enhancement of the instrumental signal are introduced. Next, the most used chemometric methods for the detection of chromatographic peaks and the resolution of chromatographic and spectral contributions (profiling) are presented. The description of these data analysis approaches is complemented with enlightening examples from omics fields that demonstrate the exceptional potential of the combination of multidimensional separation techniques and chemometric tools of data analysis.
Fabrication of Graphene Nanoplatelet/Epoxy Nanocomposites for Lightweight and High‐Strength Structural Applications
Authors: Kim Joonhui , Cha Jaemin , Jun Gwang Hoon , Yoo Sung Chan , Ryu Seongwoo , Hong Soon Hyung
Published: April 2018

Graphene nanoplatelets (GNPs), the most important mass‐produced graphene, are fabricated as a mechanical reinforcement for epoxy matrix nanocomposites. Current performance of GNPs as a reinforcing filler is limited by their agglomeration and weak interfacial interaction with certain polymer matrices. Herein, an approach to produce noncovalently functionalized GNPs (F‐GNPs) is reported that can be extended to the industrial level of mass production. The one‐step functionalization process uses melamine, a low‐cost chemical, to improve the interfacial adhesion and dispersion in an epoxy matrix. The mechanical properties of nanocomposites prepared with the F‐GNP flakes are much better (94.3% and 35.3% enhancements in Young's modulus and tensile strength, respectively) than those of the unfilled pure epoxy. Experimental data are analyzed using the Halpin–Tsai model. The fabrication process developed in this paper provides a strategy to use GNPs at the industrial level in lightweight and high‐strength structural applications.
Impact of social complexity on outcomes in cystic fibrosis after transfer to adult care
Authors: Crowley Erin M. , Bosslet Gabriel T. , Khan Babar , Ciccarelli Mary , Brown Cynthia D.
Published: April 2018

Objective

This study evaluates the roles of medical and social complexity in health care use outcomes in cystic fibrosis (CF) after transfer from pediatric to adult care.

Methods

Retrospective cohort design included patients with CF who were transitioned into adult care at Indiana University from 2005 to 2015. Predictor variables included demographic and comorbidity data, age at transition, treatment complexity score (TCS), and an objective scoring measure of their social complexity (Bob's Level of Social Support, BLSS). Outcome variables included outpatient visit rates and hospitalization rates. Pearson's correlations and linear regression were used to analyze the data.

Results

The median age of the patients (N = 133) at the time of transition was 20 (IQR 19‐23) years. The mean FEV1 % predicted at transition was 69 ± 24%. TCS correlated with outpatient visit rates (r = 0.3, P = 0.003), as well as hospitalization rates (r = 0.4, P < 0.001); while the BLSS only correlated with hospitalization rates (r = 0.7, P < 0.001). After adjusting for covariates, the strongest predictors of post‐transfer hospitalizations are BLSS (P < 0.0001) and pre‐transfer hospitalization rate (P < 0.0001).

Conclusion

Greater treatment complexity is associated with greater healthcare utilization overall, while greater social complexity is associated with increased hospitalizations (but not outpatient visits). Screening young adults for social complexity may identify high‐risk subpopulations and allow for patient centered interventions to support them and prevent avoidable health care use.
High frequency oscillatory ventilation in a cohort of children with respiratory failure
Authors: Stewart Claire A. , Yehya Nadir , Fei Lin , Chima Ranjit S.
Published: April 2018

Objectives

Our objective was to determine survival and variables associated with poor outcomes for patients requiring high frequency oscillatory ventilator (HFOV) support. We tested the ability of markers of oxygenation to predict outcome, specifically, the oxygenation index (OI), both prior to and after initiation of HFOV. We also aimed to examine the effect of immunocompromised condition (IC), and specifically stem cell transplant (SCT), on outcome.

Design

A retrospective, observational study was performed at two pediatric intensive care units (ICU) and included patients treated with HFOV over a 5 year time period. Oxygenation index and PF ratios were calculated for all patients prior to and at 24 h of HFOV support.

Results

Of the 134 patients meeting inclusion criteria, mortality was 42% with a higher rate of mortality (P < 0.001) for both immunocompromised (66%) and SCT patients (83%). Survivors had improved markers of oxygenation at 24 h as compared to non‐survivors (P < 0.001). IC and SCT were the variables most closely associated with mortality. Survivors were placed on HFOV earlier than non‐survivors. The OI at 24 h of HFOV support was the best predictor of mortality among markers of oxygenation.

Conclusions

In this cohort of patients, use of HFOV for pediatric respiratory failure demonstrated a mortality rate in keeping with published data. The presence of an immunocompromised condition was a risk factor for mortality in severe respiratory failure with SCT recipients having the lowest survival rate. The OI at 24 h was the best predictor of mortality, especially in immunocompromised and SCT patients.
Electric Field Induced Pattern Formation on PMMA and ITO Layers
Authors: Kathalingam Adaikalam , Kim Hyun‐Seok
Published: April 2018

This letter reports on electric field induced pattern formation on a spin‐coated PMMA layer. The PMMA layer is coated onto p‐type silicon substrate using a spin coater at 3000 rpm. A perpendicular electric field is produced by applying a potential difference between the PMMA film and a parallel plate ITO conductor with water trapped between them. Different patterns are formed on PMMA and ITO layers depending upon the strength of electric field and time duration. The formed patterns are studied by scanning electron microscopy and atomic force microscopy. Mechanism of pattern formation and examination of formed pattern are discussed in this report.
Silicon Quantum Dots and Their Impact on Different Human Cells
Authors: Belinova Tereza , Vrabcova Lucie , Machova Iva , Fucikova Anna , Valenta Jan , Sugimoto Hiroshi , Fujii Minoru , Hubalek Kalbacova Marie
Published: April 2018

Silicon quantum dots (SiQDs) are interesting low‐dimensional nanostructures whose unique optical and electronic properties can be exploited for imaging, biosensing, or drug delivery. SiQDs with a diameter of around 4 nm co‐doped with boron and phosphorus and evincing fluorescence and dispersibility in aqueous solutions were studied with respect to their impact on different human cells. The level of SiQD cytotoxicity in different types of human cells − osteoblasts, monocytes, macrophages, and mesenchymal stromal cells – was determined. Exposing the cells to increasing concentrations of quantum dots under different conditions and the subsequent evaluation of their cytotoxicity provided an overview of cell‐specific reactions to identical doses. The results revealed the importance of cultivation conditions (e.g., the formation of a protein corona on nanoparticles originating from the media supplement) as well as the significant impact of cell type (the increased sensitivity of monocytes to quantum dots in comparison to other cell types).