bluuebunny/crossref_metadata_2025 huggingface dataset:
Polyacrylates in the presence of an extraordinary monovalent cation—Solution behavior and metal nanoparticle formation
Authors: Urbanski Anna , Hansch Markus , Lopez Carlos G. , Schweins Ralf , Hertle Yvonne , Hellweg Thomas , Polzer Frank , Huber Klaus
Published: July 2018

Sodium polyacrylate (NaPA) in dilute aqueous solution at an ionic strength of [NaNO3] = 0.01M establishes a rich phase behavior in the presence of low amounts of silver cations, which were introduced at a few millimoles or less by replacing the corresponding amount of Na+ cations. Beyond an extremely low level of Ag+ cations, anionic PA chains aggregate. By increasing the concentration of Ag+, the aggregates become denser and keep on growing without limit. Once a certain range of [Ag+] is reached, the instantaneously formed dense aggregates remain stable. Irradiation of the PA aggregate solutions with UV-light induces formation of silver nanoparticles (Ag-Nps). Based on a combination of UV-vis spectroscopy, light scattering, transmission electron microscopy, and small angle neutron scattering, the mechanism of this NaPA assisted formation of Ag-Nps is studied. One focus of the study is lying on the effect of the two different solution states of dense aggregates, corresponding to the unstable growing AgPA aggregates and to the stable AgPA aggregates and another focus is aiming at the characterisation of the morphology of the generated hybrid particles composed of Ag-Nps and hosting PA chains.
Nonlinear ultrasonic response of voids and Cu precipitates in body-centered cubic Fe
Authors: Setyawan Wahyu , Henager Charles H. , Hu Shenyang
Published: July 2018

Interpreting nonlinear ultrasonic signals detected in a nondestructive evaluation of radiation damage requires the knowledge of the correlation between defects and nonlinearity. In this work, molecular dynamics simulations are performed to study the effect of distributed vacancies, voids, Cu atoms, and Cu precipitates on the nonlinear ultrasonic response in body-centered cubic (bcc) Fe. The nonlinearity parameter calculated from the second harmonic amplitude in the perfect lattice is 2.73. Vacancies are found to increase the nonlinearity. However, clusters of vacancies in the form of spherical voids show an opposite effect. This finding can be used to conveniently distinguish vacancies from voids in the material. Unlike vacancies, individual Cu atoms decrease the nonlinearity. Clustering of Cu atoms into Cu precipitates further decreases the nonlinearity. Interestingly, precipitates with a diameter of 2 nm and larger exhibit a similar effect despite their different structure and coherency with the Fe matrix.
Effect of grain boundary misorientation on the apparent diffusivity in nanocrystalline aluminum by atomistic simulation study
Authors: Mohammadzadeh Roghayeh , Mohammadzadeh Mina
Published: July 2018

To obtain a fundamental understanding of the effect of structure and geometry of grain boundary on the diffusion kinetics in nanocrystalline materials, the influence of grain boundary misorientation on the effective diffusion coefficient (apparent diffusivity) in nanocrystalline aluminum was investigated using molecular dynamics simulations. Nine series of [001] symmetric tilt grain boundaries, including high and low symmetric boundary planes, were studied. The apparent diffusivity in the samples was calculated in the temperature range from 423 K to 823 K by monitoring the mean square displacement of atoms as a function of simulation time. A temperature dependence of the effective diffusion coefficient according to the Arrhenius law was obtained for all samples. It is found that the apparent diffusivity is anisotropic and it is a strong function of grain boundary misorientation at low and high temperatures. At all temperatures, Σ29 [001]/(520) symmetric tilt grain boundary with misorientation angle of 43.68° exhibits the highest effective diffusion coefficient among the investigated grain boundaries. The simulation results show that the activation energy and pre-exponential factor are affected significantly by the grain boundary misorientation angle. Moreover, the results indicated that the misorientation dependence of activation energy for diffusion exhibits two local maxima, which correspond to two symmetric tilt grain boundaries. Additional calculation of misorientation dependence of the pre-exponential factor shows two local minima at the same symmetric tilt grain boundaries. The misorientation dependence of the effective diffusion coefficient was explained on the basis of grain boundary energy and the crystallographic structure of grain boundary.
Development of an ordinary mode multi-channel correlation reflectometer on EAST tokamak
Authors: Xiang H. M. , Zhang T. , Wen F. , Qu H. , Wu M. F. , Geng K. N. , Li G. S. , Wang Y. M. , Han X. , Liu Zi X. , Zhong F. B. , Ye K. X. , Zhang S. B. , Gao X.
Published: July 2018

An ordinary-mode polarized multi-channel correlation reflectometer has been developed on the Experimental Advanced Superconducting Tokamak (EAST). The system with four different probing frequencies (i.e., 20.4 GHz, 24.8 GHz, 33 GHz, and 40 GHz) and two poloidally spaced receiving antennas can realize both the radial correlation measurement and the poloidal correlation measurement. These diagnostics focus on the measurement of density fluctuation in the pedestal region to investigate the turbulence transport and H-mode physics on EAST. In this article, the system hardware design, the key component tests, and the system performance are shown in detail.
Impact of the degree of Cu–Zn order in Cu2ZnSn(S,Se)4 solar cell absorbers on defect states and band tails
Authors: Lang Mario , Renz Tobias , Opolka Alexander , Zimmermann Christian , Krämmer Christoph , Neuwirth Markus , Kalt Heinz , Hetterich Michael
Published: July 2018

In order to identify the impact of the degree of Cu–Zn order in kesterite Cu2ZnSn(S,Se)4 solar cell absorbers on defect states and band tails, we perform photoluminescence (PL), photoluminescence excitation, and time-resolved photoluminescence (TRPL) spectroscopy. The PL lineshape and further PL characteristics such as state filling are analysed as a function of Cu–Zn order. Furthermore, TRPL decays and band tails are quantified. No significant modification in the defect states is caused by changes in Cu–Zn order, meaning that the formation of the defect states is not mainly determined by disorder in the Cu–Zn plane. In regard to band tailing, a small tendency to a decrease in the tailing parameter for the states with a high degree of Cu–Zn order compared to states with a low degree of Cu–Zn order is obvious. However, this reduction is small compared to the reduction of the defect density accompanied by the increase in the degree of Cu–Zn order. Hence, band tails are not mainly formed due to disorder in the Cu–Zn planes.
On measuring the fracture energy of model metallic glasses
Authors: Deng Binghui , Shi Yunfeng
Published: July 2018

We report a heuristic approach to measure the fracture energy of model metallic glasses using molecular dynamics simulation. Specifically, we adopted the Rivlin-Thomas method, simplified by Suo et al., which is applicable even with the presence of plastic flow. We further modified the testing condition with semi-rigid holders in our molecular simulations, to avoid unintended fracture near the holders. This method was first applied in measuring the fracture energy of a brittle model glass, which agrees well with direct KIC and JIC measurements (both measurements are independent of the crack size). Furthermore, the fracture energy values of a family of model metallic glasses, ranging from brittle to ductile (BTD), were measured. The Poisson's ratio-fracture energy (v-G, or v-G/2γ, normalized by the surface energy) relation obtained here exhibits a BTD transition at a critical Poisson's ratio of 0.31–0.32, consistent with experimental results.
Formability and magnetic properties of Dy-Co binary amorphous alloys
Authors: Ma L. Y. , Tang B. Z. , Chan K. C. , Zhao L. , Tang M. B. , Ding D. , Xia L.
Published: July 2018

In this study, binary Dy-Co ribbons were synthesized by a conventional melt-spinning approach and glassy ribbons were successfully obtained within the compositional range Dy50Co50 to Dy68Co32. The glass formability and magnetic properties of these amorphous alloys were examined. The compositional dependence of glass formability, Curie temperature and magneto-caloric response of the DyxCo100-x (x=50, 55, 60, 65 and 68) amorphous alloys, as well as the mechanism involved, were determined.
Filamentary velocity scaling validation in the TCV tokamak
Authors: Tsui C. K. , Boedo J. A. , Myra J. R. , Duval B. , Labit B. , Theiler C. , Vianello N. , Vijvers W. A. J. , Reimerdes H. , Coda S. , Février O. , Harrison J. R. , Horacek J. , Lipschultz B. , Maurizio R. , Nespoli F. , Sheikh U. , Verhaegh K. , Walkden N. ,   TCV Team,,   EUROfusion MST1 Team
Published: July 2018

A large database of reciprocating probe data from the edge plasma of TCV (Tokamak à Configuration Variable) is used to test the radial velocity scalings of filaments from analytical theory [Myra et al., Phys. Plasmas 13, 112502 (2006)]. The measured velocities are mainly scattered between zero and a maximum velocity which varies as a function of size and collisionality in agreement with the analytical scalings. The scatter is consistent with mechanisms that tend to slow the velocity of individual filaments. While the radial velocities were mainly clustered between 0.5 and 2 km/s, a minority reached outward velocities as high as 5 km/s or inward velocities as high as −4 km/s. Inward moving filaments are only observed in regions of high poloidal velocity shear in discharges with B × ∇B away from the X-point, a new finding. The filaments have diameters clustered between 3 and 11 mm, and normalized sizes â clustered between 0.3 and 1.1, such that most filaments populate the resistive-ballooning regime; therefore, most of the filaments in TCV have radial velocities with little or no dependence on collisionality. Improvements in cross-correlation techniques and conditional averaging techniques are discussed which reduce the sizes determined for the largest filaments, including those larger than the scrape-off layer.
Enhancement of the deep-level emission and its chemical origin in hexagonal boron nitride
Authors: Tsushima Emi , Tsujimura Takuya , Uchino Takashi
Published: July 2018

Defect-related deep-level emissions at ∼4 eV from hexagonal boron nitride (h-BN) have been extensively investigated during the past decades. Although the emission has often been associated with deep level impurities such as carbon and oxygen, the structural and chemical origins of the emission center have not yet been identified. Here, we perform systematic photoluminescence measurements and quantitative trace impurity analysis of variously heat-treated h-BN samples with different deep-level emission intensities. In contrast to the common belief, no positive correlation between the impurity (carbon and oxygen) concentration and the deep-level emission intensity was found. We also demonstrate that the intensity of the deep-level emission is significantly enhanced by high-temperature heating (∼1900 °C) under an N2 environment and subsequent post-annealing at ∼900 °C. These results suggest that intrinsic defects created under N2-rich conditions are responsible for the deep-level emission. Furthermore, we found that besides the well-recognized zero-phonon line (ZPL) at ∼4.1 eV, additional ZPLs are induced in the near ultraviolet (NUV) region by appropriate annealing of the N2-treated h-BN sample. The results of temperature-dependent and time-resolved PL measurements on these NUV emission bands are given and discussed.
A double network hydrogel with high mechanical strength and shape memory properties
Authors: Zhu Lei , Xiong Chun-ming , Tang Xiao-fen , Wang Li-jun , Peng Kang , Yang Hai-yang
Published: July 2018

Double network (DN) hydrogels as one kind of tough gels have attracted extensive attention for their potential applications in biomedical and load-bearing fields. Herein, we import more functions like shape memory into the conventional tough DN hydrogel system. We synthesize the PEG-PDAC/P(AAm-co-AAc) DN hydrogels, of which the first network is a well-defined PEG (polyethylene glycol) network loaded with PDAC (poly(acryloyloxyethyltrimethyl ammonium chloride)) strands, while the second network is formed by copolymerizing AAm (acrylamide) with AAc (acrylic acid) and cross-linker MBAA (N, N′-methylenebisacrylamide). The PEG-PDAC/P(AAm-co-AAc) DN gels exhibits high mechanical strength. The fracture stress and toughness of the DN gels reach up to 0.9 MPa and 3.8 MJ/m3, respectively. Compared with the conventional double network hydrogels with neutral polymers as the soft and ductile second network, the PEG-PDAC/P(AAm-co-AAc) DN hydrogels use P(AAm-co-AAc), a weak polyelectrolyte, as the second network. The AAc units serve as the coordination points with Fe3+ ions and physically crosslink the second network, which realizes the shape memory property activated by the reducing ability of ascorbic acid. Our results indicate that the high mechanical strength and shape memory properties, probably the two most important characters related to the potential application of the hydrogels, can be introduced simultaneously into the DN hydrogels if the functional monomer has been integrated into the network of DN hydrogels smartly.
Influence of electron donating ability on reverse intersystem crossing rate for one kind of thermally activated delayed fluorescence molecules
Authors: Wang Ming-lang , Fan Jian-zhong , Lin Li-li
Published: July 2018

First-principles calculations are applied for investigating influence of electron donating ability of donor groups in eight thermally activated delayed fluorescence (TADF) molecules on their geometrical structures and transition properties as well as reverse intersystem crossing (RISC) processes. Results show that the diphenylamine substitution in the donor part can slightly change the bond angle but decrease bond length between donor and acceptor unit except for the lowest triplet state (T1) of carbazole-xanthone molecule. As the electron donating ability of donor groups is increased, the overlap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is decreased. As the diphenylamine groups are added in donor part, the delocalization of HOMO is enlarged, which brings a decreased energy gap (ΔES1-T1) between the lowest singlet excited state (S1) and T1 state. Furthermore, with the calculated spin-orbit coupling coefficient (Hso), one finds that the larger value of 〈S1|H^so|T1〉2ΔES1−T12 is, the faster the RISC is. The results show that all investigated molecules are promising candidates as TADF molecules. Overall, a wise molecular design strategy for TADF molecules, in which a small ΔES1-T1 can be achieved by enlarging the delocalization of frontier molecular orbitals with large separation between HOMO and LUMO, is proposed.
Order-Disorder transition of carboxyl terminated chains in polydiacetylenes vesicles probed by second harmonic generation and two-photon fluorescence
Authors: Chen Shun-li , Zhu Xue-feng , Yang Fang-yuan , Pan Xue-cong , Gan Wei , Yuan Qun-hui
Published: July 2018

To understand and control the interfacial properties of polydiacetylenes (PDAs) vesicles with π-conjugated backbone is very important for their colorimetric sensing of chemical and biological targets. In this work, we adopted 10, 12-pentacosadiynoic acid (PCDA) as the model molecule to prepare PDAs vesicles in aqueous solution with different forms (from monomer to blue-to-purple-to-red phase) by controlling the UV irradiation dose. The variations of the interfacial conformation of PDAs vesicles during chromatic transitions were inspected by the adsorption behaviors of probe molecules (4-(4-diethylaminostyry)-1-methylpyridinium iodide, D289) on vesicle surface with surface-specific second harmonic generation (SHG) and zeta potential measurements. Resonant SHG signal from D289 adsorbed on vesicle surface attenuated sharply, and the adsorption free energy as well as the corresponding two-photon fluorescence signal decreased slightly in chromatic transitions. While, the change in the surface density of the adsorbed D289 molecules for PDAs vesicles with different forms was relatively small as estimated from zeta potential measurements. The attenuation of the SHG intensity was thus attributed to the overall order-disorder transition and the changed orientation of D289 molecules caused by the gradual distortion of carboxyl head group driven by backbone perturbation.
Ultrafast dynamics of defect-assisted carrier capture in MoS2 nanodots investigated by transient absorption spectroscopy
Authors: Ke Da , Sui Lai-zhi , Liu Dun-li , Cui Jian-qiu , Zhang Yun-feng , Li Qing-yi , Li Su-yu , Jiang Yuan-fei , Chen An-min , Song Jun-ling , Jin Ming-xing
Published: July 2018

MoS2 nanodots are emerging as promising semiconductor materials for optoelectronic devices. However, most of the recent attention is focused on the fabrication of MoS2 nanodots, and the survey for exciton dynamics of MoS2 nanodots remains less explored. Herein, we use femtosecond transient absorption spectroscopy to investigate the carrier dynamics of MoS2nanodots. Our results show that defect-assisted carrier recombination processes are well consistent with the observed dynamics. The photo-excited carriers are captured by defects with at least two different capture rates via Auger scattering. Four processes are deemed to take part in the carrier relaxation. After photoexcitation, carrier cooling occurs instantly within ~0.5 ps. Then most of carriers are fast captured by the defects, and the corresponding time constant increases from ~4.9 ps to ~9.2 ps with increasing pump fluence, which may be interpreted by saturation of the defect states. Next a small quantity of carriers is captured by the other kinds of defects with a relatively slow carrier capture time within ~65 ps. Finally, the remaining small fraction of carriers relaxes via direct interband electron-hole recombination within ~1 ns. Our results may lead to deep insight into the fundamentals of carrier dynamics in MoS2 nanodots, paving the way for their further applications.
Thermoresponsive Polymer Grafted Porous Silicas as Smart Nanocarriers
Authors: Jadhav Sushilkumar A. , Scalarone Dominique
Published: July 2018

Porous silica particles grafted with various stimuli-responsive polymers are investigated with great interest for their use as smart pharmaceutical nanocarriers in advanced drug delivery systems (DDS). In particular, porous silica particles grafted with thermoresponsive polymers that exhibit thermally triggered on/off gating mechanisms have shown improved performance as hybrid DDS capable of controlling the release of different drugs in various mediums which resemble complex biological environments. In addition, the tuning of the drug release profiles as per requirements has proved possible with modifications to the porous core and the grafted thermoresponsive polymers. This highlight presents a brief discussion of basic preparation techniques and some recent significant developments in the field of thermoresponsive polymer grafted porous silica particles as smart pharmaceutical nanocarriers.
Fish movement patterns in a Neotropical free-flowing tributary located downstream from a large dam
Authors: Casarim Ruanny , Prado Ivo Gavião , Loures Raquel Coelho , Pompeu Paulo Santos
Published: July 2018

In dammed rivers, the conservation of free-flowing tributaries is considered an important strategy to mitigate the negative effects of the dam on fish communities. In this study, we evaluated the importance of a free-flowing tributary of a dammed river as a reproductive migration route. From August 2012 to July 2013, hydroacoustics data were collected alongside active fish sampling using cast nets and ichthyoplankton nets in the São Francisco and Abaeté rivers. Cast net sampling captured 738 individuals and hydroacoustics detected 42196 fishes. In almost all samples and sampling sites, preferential movements to the Abaeté River and the main São Francisco River were observed. The increase in the flow rate of the Abaeté coincided with a greater incidence of fish movements to upstream areas of the tributary. A higher density and proportion of larger fishes, as well as a higher density of ichthyoplankton, were observed in the Abaeté River compared with the main river. Because this tributary is an alternative route for migratory fishes, its protection is essential for fish conservation and therefore maintenance of local fisheries
Biogeographic regions and events of isolation and diversification of the endemic biota of the tropical Andes
Authors: Hazzi Nicolas A. , Moreno Juan Sebastián , Ortiz-Movliav Carolina , Palacio Rubén Darío
Published: July 2018

Significance

This study unifies quantitative methods with dated molecular phylogenies of different lineages to identify biogeographical regions and understand the spatial and temporal evolution of the biota in one of the most biodiverse hotspots of the planet, the tropical Andes. We found complex distribution patterns reflected in a significantly higher number of bioregions than previous regionalization work has identified. In addition, this study found evidence that bioregions’ drivers were processes of Andean uplift and mountain dispersal facilitated by temperature oscillations during the Pleistocene. Therefore, Andean bioregions were formed from a combination of vicariance and dispersal events, which occurred in different time periods. Our results will help set conservation priorities that preserve the evolutionary patterns of biodiversity.
Remediation of a Beneficial Use Impairment at Bluffer’s Park Beach in the Toronto Area of Concern
Authors: Edge T. A. , Hill S. , Crowe A. , Marsalek J. , Seto P. , Snodgrass B. , Toninger R. , Patel M.
Published: July 2018

Bluffer’s Park Beach in the Toronto and Region Area of Concern had a history of beach postings often exceeding 80% of the beach season since the 1980s. A study applied expanded E. coli surveillance and microbial source tracking techniques in 2005–2007 to identify fecal pollution sources contributing to beach postings. Expanded surveillance in the beach vicinity identified significant E. coli hotspots in the foreshore beach sand (pore water max E. coli = 255,000 CFU 100 ml−1) and associated with a marsh inland of the beach. During rain events, streams from the marsh (max E. coli = 173,000 CFU 100 ml−1) and runoff from the parking lot (max E. coli = 4100 CFU 100 ml−1) were observed to overflow across the beach to contaminate beach waters. Microbial source tracking using library-dependent (antibiotic resistance and rep-PCR DNA fingerprinting of E. coli isolates) and library-independent (human HF183 bacterial DNA marker) methods indicated the prevalence of animal fecal pollution sources at the beach rather than human sewage. These results were consistent with sanitary survey information, observations of wildlife in the marsh area, and Gulls and Canada Geese on the beach. In 2006, a bird management program was initiated, and remedial actions continued in advance of the 2008 bathing season to engineer a berm to prevent marsh runoff into beach water and re-direct parking lot drainage into the marsh. Since these remediation actions, Bluffer’s Park Beach has been posted less than 20% of each beach season, and it was awarded a Blue Flag accreditation in 2011.
Monitoring water quality on the central Toronto waterfront: Perspectives on addressing spatiotemporal variability
Authors: Howell E. T. , Dahmer S. C. , Chomicki K. M. , Benoit N. , Boyd D. , Bowen G. S.
Published: July 2018

Toronto Harbour, adjacent to a large urban centre on Lake Ontario, receives inputs from storm sewers, combined sewer overflows, and urban runoff that lead to contrasting water quality over the waterfront. Toronto’s Inner and Outer Harbours, mesotrophic and meso-oligotrophic, respectively, were investigated in 2008 to assess how water quality conditions were affected by loading gradients, weather and lake circulation. Spatially-intensive measurements of UV fluorescence, turbidity, conductivity, and chlorophyll a, together with lab-based analysis of chemistry at discrete sites, were used to depict patterns and contrasts in water quality in the harbour. Spatially-integrated field sensor data were also employed to examine the efficacy of using discrete water quality sampling to represent average conditions. Nitrogen, total phosphorus, dissolved organic carbon, major ions and E. coli gradients were a recurrent feature among surveys with concentrations decreasing away from the Don River mouth. The limited point-sample data reasonably depicted average conditions among areas of the harbour on the days of survey as did the results interpolated for a long-term monitoring station in the Inner Harbour. The strong variability seen within the Inner Harbour indicates that the most affected water quality conditions are likely under represented by area-wide conditions. Temporal variability in water quality, correlated with the discharge from the Don River, was strong yet under represented by the field-based sampling. Empirical prediction of total phosphorus concentrations in the Inner Harbour, and correlated with Don River discharge, were used to demonstrate both the critical need to address temporal variability in monitoring design and the possibility of using empirical predictive approaches drawing upon field sensor data to fill this gap.
Effect of resistance training with different frequencies and subsequent detraining on muscle mass and appendicular lean soft tissue, IGF‐1, and testosterone in older women
Authors: Nascimento Matheus Amarante Do , Gerage Aline Mendes , Silva Danilo Rodrigues Pereira Da , Ribeiro Alex Silva , Machado Daniel Gomes Da Silva , Pina Fábio Luiz Cheche , Tomeleri Crisieli Maria , Venturini Danielle , Barbosa Décio Sabbatini , Mayhew Jerry L. , Cyrino Edilson Serpeloni
Published: July 2018

Objective: To analyse the effect of resistance training (RT) frequency on muscle mass, appendicular lean soft tissue, insulin‐like growth factor 1 (IGF‐1), testosterone, and their changes with detraining in older women. Methods: Forty‐five physically independent older women (≥ 60 years) were randomly assigned to perform RT either two (G2X, n = 21) or three times/week (G3X, n = 24), during 12 weeks (8 exercises, 1 set of 10–15 repetition maximum). Muscle mass and appendicular lean soft tissue, IGF‐1, testosterone, and dietary intake were measured at pre‐training, post‐training, and after detraining (12 weeks). Results: Muscle mass and appendicular lean soft tissue significantly increased post‐training (G2X = +5.5% and G3X = +5.8%, P < .0001) with no differences between groups, and gains were retained after detraining (G2X = 100% and G3X = 99%, P < .0001). IGF‐1 and dietary intake did not change for the groups during the study. Testosterone did not change post‐training but significantly decreased after detraining (G2X = −21% and G3X = −50%, P < .0001). Conclusion: We conclude that lower RT frequency is as effective as higher frequency to improve muscle mass and appendicular lean soft tissue, and to maintain testosterone and IGF‐1. Additionally, detraining may reduce testosterone regardless of RT frequency. These results are specifically for community‐dwelling older women and may not be generalized to other populations.
Corticospinal changes induced by fatiguing eccentric versus concentric exercise
Authors: Garnier Yoann M. , Paizis Christos , Lepers Romuald
Published: July 2018

The present study assessed neuromuscular and corticospinal changes during and after a fatiguing submaximal exercise of the knee extensors in different modes of muscle contraction. Twelve subjects performed two knee extensors exercises in a concentric or eccentric mode, at the same torque and with a similar total impulse. Exercises consisted of 10 sets of 10 repetitions at an intensity of 80% of the maximal voluntary isometric contraction torque (MVIC). MVIC, maximal voluntary activation level (VAL) and responses of electrically evoked contractions of the knee extensors were assessed before and after exercise. Motor evoked potential amplitude (MEP) and cortical silent period (CSP) of the vastus medialis (VM) and rectus femoris (RF) muscles were assessed before, during and after exercise. Similar reductions of the MVIC (−13%), VAL (−12%) and a decrease in the peak twitch (−12%) were observed after both exercises. For both VM and RF muscles, MEP amplitude remained unchanged during either concentric or eccentric exercises. No change of the MEP amplitude input–output curves was observed post‐exercise. For the RF muscle, CSP increased during the concentric exercise and remained lengthened after this exercise. For the VM muscle, CSP was reduced after the eccentric exercise only. For a similar amount of total impulse, concentric and eccentric knee extensor contractions led to similar exercise‐induced neuromuscular response changes. For the two muscles investigated, no modulation of corticospinal excitability was observed during or after either concentric or eccentric exercises. However, intracortical inhibition showed significant modulations during and after exercise.
Molecular subtypes and differentiation programmes of glioma stem cells as determinants of extracellular vesicle profiles and endothelial cell‐stimulating activities
Authors: Spinelli C. , Montermini L. , Meehan B. , Brisson A. R. , Tan S. , Choi D. , Nakano I. , Rak J.
Published: July 2018

We have previously uncovered the impact of oncogenic and differentiation processes on extracellular vesicles (EVs) in cancer. This is of interested in the context of glioma stem cells (GSC) that are responsible for recurrent nature of glioblastoma multiforme (GBM), while retaining the potential to undergo differentiation and self renewal.  GSCs reside in vascular niches where they interact with endothelial cells through a number of mediators including bioactive cargo of EVs. GSCs can be classified as proneural (PN) or mesenchymal (MES) subtypes on the basis of their gene expression profiles and distinct biological characteristics. In the present study we investigated how GSC diversity and differentiation programmes influence their EV‐mediated communication potentials. Indeed, molecular subtypes of GBMs and GSCs differ with respect to their expression of EV‐related genes (vesiculome) and GSCs with PN or MES phenotypes produce EVs with markedly different characteristics, marker profiles, proteomes and endothelial stimulating activities. For example, while EVs of PN GSC are largely devoid of exosomal markers their counterparts from MES GSCs express ample CD9, CD63 and CD81 tetraspanins. In both GSC subtypes serum‐induced differentiation results in profound, but distinct changes of cellular phenotypes including the enhanced EV production, reconfiguration of their proteomes and the related functional pathways. Notably, the EV uptake was a function of both subtype and differentiation state of donor cells. Thus, while, EVs produced by differentiated MES GSCs were internalized less efficiently than those from undifferentiated cells they exhibited an increased stimulatory potential for human brain endothelial cells. Such stimulating activity was also observed for EVs derived from differentiated PN GSCs, despite their even weaker uptake by endothelial cells. These findings suggest that the role of EVs as biological mediators and biomarkers in GBM may depend on the molecular subtype and functional state of donor cancer cells, including cancer stem cells.

Abbreviations: CryoTEM: cryo‐transmission electron microscopy; DIFF: differentiated GSCs; EGF: epidermal growth factor; DUC: differential ultracentrifugation; EV: extracellular vesicle; FGF: fibroblast growth factor; GBM: glioblastoma multiforme; GFAP: glial fibrillary acidic protein; GO: gene ontology; GSC: glioma stem cells; HBEC‐5i: human brain endothelial cells; MES: mesenchymal cells; MTS ‐ [3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium, inner salt; PMT1: proneural‐to‐mesenchyman transition cell line 1; PN: proneural cells; TEM: transmission electron microscopy; WB: western blotting
Discussing What Would Happen: The Role of Thought Experiments in Galileo’s Dialogues
Authors: Palmerino Carla Rita
Published: July 2018

Thought experiments play an important epistemic, rhetorical, and didactic function in Galileo’s dialogues. In some cases, Salviati, Sagredo, and Simplicio agree about what would happen in an imaginary scenario and try to understand whether the predicted outcome is compatible with their respective theoretical assumptions. There are, however, also situations in which the predictions of the three interlocutors turn out to be theory laden. Salviati, Sagredo, and Simplicio not only disagree about what would happen, but they reject one another’s solutions as question begging and sometimes even dismiss one another’s thought experiments as misleading or nonsensical.
Addressing Industry-Funded Research with Criteria for Objectivity
Authors: Elliott Kevin C.
Published: July 2018

In recent years, industry-funded research has come under fire because of concerns that it can be biased in favor of the funders. This article suggests that efforts by philosophers of science to analyze the concept of objectivity can provide important lessons for those seeking to evaluate and improve industry-funded research. It identifies three particularly relevant criteria for objectivity: transparency, reproducibility, and effective criticism. On closer examination, the criteria of transparency and reproducibility turn out to have significant limitations in this context, but the criterion of effective criticism suggests some important strategies for improving the objectivity of industry-funded science.
Understanding Leopold’s Concept of “Interdependence” for Environmental Ethics and Conservation Biology
Authors: Millstein Roberta L.
Published: July 2018

Aldo Leopold’s land ethic, an extremely influential view in environmental ethics and conservation biology, is committed to the claim that interdependence between humans, other species, and abiotic entities plays a central role in our ethical responsibilities. Thus, a robust understanding of “interdependence” is necessary for evaluating the viability of the land ethic and related views, including ecological ones. I characterize and defend a Leopoldian concept of “interdependence,” arguing that it ought to include both negative and positive causal relations. I also show that strength and type of interdependence can vary with time, space, and context.
Renormalization and the Formulation of Scientific Realism
Authors: Fraser James D.
Published: July 2018

Providing a precise statement of their position has long been a central challenge facing scientific realists. This article draws some morals about how realism ought to be formulated from the renormalization group framework in high-energy physics.
The (A)temporal Emergence of Spacetime
Authors: Huggett Nick , Wüthrich Christian
Published: July 2018

This article examines two cosmological models of quantum gravity (from string theory and loop quantum gravity) to investigate the foundational and conceptual issues arising from quantum treatments of the big bang. While the classical singularity is erased, the quantum evolution that replaces it may not correspond to classical spacetime: it may instead be a nonspatiotemporal region that somehow transitions to a spatiotemporal state. The different kinds of transition involved are partially characterized, the concept of a physical transition without time is investigated, and the problem of empirical incoherence for regions without spacetime is discussed.
Strategies of Explanatory Abstraction in Molecular Systems Biology
Authors: Jones Nicholaos
Published: July 2018

I consider three explanatory strategies from recent systems biology that are driven by mathematics as much as mechanistic detail. Analysis of differential equations drives the first strategy; topological analysis of network motifs drives the second; mathematical theorems from control engineering drive the third. I also distinguish three abstraction types: aggregations, which simplify by condensing details; generalizations, which simplify by generalizing details; and structurations, which simplify by contextualizing details. Using a common explanandum as a reference point—namely, the robust perfect adaptation of chemotaxis in Escherichia coli—I argue that each strategy targets various abstraction types to different mechanistic details.
The Evolution of Psychological Altruism
Authors: Piccinini Gualtiero , Schulz Armin
Published: July 2018

We argue that there are two different kinds of altruistic motivation: classical psychological altruism, which generates ultimate desires to help other organisms at least partly for those organisms’ sake, and nonclassical psychological altruism, which generates ultimate desires to help other organisms for the sake of the organism providing the help. We then argue that classical psychological altruism is adaptive if the desire to help others is intergenerationally reliable and, thus, need not be learned. Nonclassical psychological altruism is adaptive when the desire to help others is adaptively learnable. This theory opens new avenues for the interdisciplinary study of psychological altruism.
Natural dye extracts from fruit peels as sensitizer in ZnO-based dye-sensitized solar cells
Authors: Adedokun Oluwaseun , Awodele Mojoyinola Kofoworola , Sanusi Yekinni Kolawole , Awodugba Ayodeji Oladiran
Published: July 2018

As a result of twin problems of environmental pollution and continuous depletion of fossil fuels, a search for renewable and clean energy sources is necessary. This paper discusses the simple extraction techniques without any further purification of natural dyes from some fruit peels and their performance in DSSCs. Natural dyes extracted from fruit peels of Carica papaya, Citrus lanatus, Persea americana and Solanum melongena were used as sensitizers to fabricate ZnO-based dye-sensitized solar cells (DSSCs). The extracts of the natural dyes were characterized and studied using UV-Vis absorption spectroscopy, Fourier transforms infra-red (FTIR) and Photoluminescence (PL) spectroscopy. The photo-anode semiconductor material was prepared and characterized. The photo-voltaic characteristics of the fabricated DSSCs were measured under simulated solar light (power of incident light 100 mWcm-2 from Air Mass 1.5G). These studies indicated the presence of pheophytin ‘a’ in most of the extracts studied as the main pigments with other accessory pigments. The solar to electric conversion efficiencies for the pheophytin ‘a’ dye based solar cells are estimated as 0.017%, 0.013%, 0.010% and 0.011% for Carica papaya, Citrus lanatus, Persea americana and Solanum melongena, respectively. The dye extracts from Carica papaya exhibits higher photo-sensitized performance compared to the other extracts and this is due to the better charge transfer between the dyes of Carica papaya and ZnO photo-anode surface. Conversion of visible light into electricity was accomplished with natural dyes and ZnO-based DSSCs, resulting in excellent photo-electric properties compared to those in literature.
Rethinking Hierarchies in East Asian Historical IR
Authors: MacKay Joseph
Published: July 2018

International relations (IR) has seen a proliferation of recent research on both international hierarchies as such and on historical IR in (often hierarchical) East Asia. This article takes stock of insights from East Asian hierarchies for the study of international hierarchy as such. I argue for and defend an explanatory approach emphasizing repertoires or toolkits of hierarchical super- and subordination. Historical hierarchies surrounding China took multiple dynastic forms. I emphasize two dimensions of variation. First, hierarchy-building occurs in dialogue between cores and peripheries. Variation in these relationships proliferated multiple arrangements for hierarchical influence and rule. Second, Sinocentric hierarchies varied widely over time, in ways that suggest learning. Successive Chinese dynasties both emulated the successes and avoided the pitfalls of the past, adapting their ideologies and strategies for rule to varying circumstances by recombining past political repertoires to build new ones. Taken together, these phenomena suggest new lines of inquiry for research on hierarchies in IR.
Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Pharmacological Treatment
Authors: Arnold Paul M , Anderson Paul A , Chi John H , Dailey Andrew T , Dhall Sanjay S , Eichholz Kurt M , Harrop James S , Hoh Daniel J , Qureshi Sheeraz , Rabb Craig H , Raksin P B , Kaiser Michael G , O’Toole John E
Published: July 2018

QUESTION

Does the administration of a specific pharmacologic agent (eg, methylprednisolone) improve clinical outcomes in patients with thoracic and lumbar fractures and spinal cord injury?

RECOMMENDATION

There is insufficient evidence to make a recommendation; however, the task force concluded, in light of previously published data and guidelines, that the complication profile should be carefully considered when deciding on the administration of methylprednisolone.

Strength of recommendation: Grade Insufficient

The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_5.
A valid alternative for in-person language assessments in brain tumor patients: feasibility and validity measures of the new TeleLanguage test
Authors: De Witte Elke , Piai Vitória , Kurteff Garret , Cai Ruofan , Mariën Peter , Dronkers Nina , Chang Edward , Berger Mitchel
Published: July 2018

Background

Although language deficits after awake brain surgery are usually milder than post-stroke, postoperative language assessments are needed to identify these. Follow-up of brain tumor patients in certain geographical regions can be difficult when most patients are not local and come from afar. We developed a short telephone-based test for pre- and postoperative language assessments.

Methods

The development of the TeleLanguage Test was based on the Dutch Linguistic Intraoperative Protocol and existing standardized English batteries. Two parallel versions were composed and tested in healthy native English speakers. Subsequently, the TeleLanguage Test was administered in a group of 14 tumor patients before surgery and at 1 week, 1 month, and 3 months after surgery. The test includes auditory comprehension, repetition, semantic selection, sentence or story completion, verbal naming, and fluency tests. It takes less than 20 minutes to administer.

Results

Healthy participants had no difficulty performing any of the language tests via the phone, attesting to the feasibility of a phone assessment. In the patient group, all TeleLanguage test scores significantly declined shortly after surgery with a recovery to preoperative levels at 3 months postsurgery for naming and fluency tasks and a recovery to normal levels for the other language tasks. Analysis of the in-person language assessments (until 1 month) revealed a similar profile.

Conclusion

The use of the TeleLanguage battery to conduct language assessments from afar can provide convenience, might optimize patient care, and enables longitudinal clinical research. The TeleLanguage is a valid tool for various clinical and scientific purposes.
Effects of Cigarette Prices on Intention to Quit, Quit Attempts, and Successful Cessation Among African American Smokers
Authors: Keeler Courtney , Max Wendy , Yerger Valerie B , Yao Tingting , Wang Yingning , Ong Michael K , Sung Hai-Yen
Published: July 2018

Introduction

This study examined the effects of cigarette price on intention to quit, quit attempts, and successful cessation among African American smokers in the United States and explored whether price effects differed by income level and menthol use status. Price effects were further compared to White counterparts.

Methods

We used pooled cross-sectional data from 2006 to 2007 and 2010 to 2011 Tobacco Use Supplements to the Current Population Survey to analyze 4213 African American recent active smokers. Three dependent variables were examined: any quit attempts in the past 12 months, successful cessation for at least 3 months, and intention to quit in the next 6 months. For each dependent variable, separate multiple logistic regression models were estimated to determine the impact of cigarette prices.

Results

There was no indication that price was associated with quit attempts or successful cessation, but price was positively associated with increased odds of intending to quit among African American smokers (p < .001). In contrast, prices were positively associated with intention to quit and quit attempts for White smokers. The association between price and intention to quit was significantly positive for African American low-income and menthol smokers but was not statistically significant for African American high-income and non-menthol smokers. There was no evidence of a price effect on quit attempts and successful cessation for each subgroup of African Americans.

Conclusions

Tobacco tax policy alone may not be enough to increase quit attempts or successful cessation among African Americans. Community-based cessation programs tailored toward African American smokers, especially low-income menthol smokers, are needed.

Implications

The results revealed that, among African American smokers, particularly among low-income and menthol smoking African American smokers, price appears to be positively associated with intention to quit; nevertheless, this deterrent effect does not appear to translate to actualized quit attempts or successful cessation. Increasing cigarette prices as a standalone policy may not be independently effective in increasing quit attempts and successful cessation within the African American community. Community-based cessation interventions tailored for African Americans are needed to help further translate desired cessation into actualized quit attempts.
Lateral Transpsoas Approach for Lumbar Indirect Lateral Recess Decompression: 2-Dimensional Operative Video
Authors: Landriel Federico , Hem Santiago , Yampolsky Claudio
Published: July 2018

Neurogenic claudication is a common symptom of lumbar spinal stenosis; its pathophysiology is thought to be ischemia of the nerve roots secondary to compression from surrounding structures. The stenosis of the lateral recesses and neuroforamen can cause these symptoms and its surgical treatment is decompression. The placement of interbody cages that restore the disc space height may indirectly decompress the neuroforamen and alleviate the nerve impingement symptoms. In case of concomitant low-grade spondylolisthesis, interbody devices might also reduce the slippage. We present a technical surgical video of a minimally invasive lateral transpsoas fusion, relying on indirect decompression to treat a patient with neurogenic claudication secondary to grade 1 spondylolisthesis. The patient signed a written consent to publish a video, recording, photograph, image, illustration, and/or information about him.