bluuebunny/crossref_metadata_2025 huggingface dataset:
Rational in situ tuning of a supramolecular photocatalyst for hydrogen evolution
Authors: Kaufhold S. , Imanbaew D. , Riehn C. , Rau S.
Published: September 2017

In situ exchange of co-ligands in a molecular photocatalyst significantly boosts light driven hydrogen formation.
Chalcogenide and pnictide nanocrystals from the silylative deoxygenation of metal oxides
Authors: Lin Chia-Cheng , Tan Shannon J. , Vela Javier
Published: September 2017

Transition metal chalcogenides and pnictides are interesting in optoelectronics and catalysis. We present a generalized method to transform preformed metal oxide nanocrystals into sulfides, selenides, or phosphides via silylative deoxygenation with trimethylsilyl reagents. In all reactions studied, simultaneous decomposition of excess silyl reagent produces a protective, amorphous silica coating around the newly formed nanocrystals.
Advanced sodium storage property in an exfoliated MoO3 anode: the stability and performance improvement by in situ impedance mapping
Authors: Roy Amlan , Dutta Prasit Kumar , Mitra Sagar
Published: September 2017

A two-step modification to morphology in conjunction with in situ PEIS mapping are employed to achieve high capacity and improved retention in a stepwise manner.
Rational design of Li3VO4@carbon core–shell nanoparticles as Li-ion hybrid supercapacitor anode materials
Authors: Lim Eunho , Lim Won-Gwang , Jo Changshin , Chun Jinyoung , Kim Mok-Hwa , Roh Kwang Chul , Lee Jinwoo
Published: September 2017

A Li-ion hybrid supercapacitor (Li-HSC) delivering high energy within seconds (excellent rate performance) with stable cycle life is one of the most highly attractive energy storage devices.
Hydrogen production with ultrahigh efficiency under visible light by graphene well-wrapped UiO-66-NH2 octahedrons
Authors: Wang Yang , Yu Yu , Li Rui , Liu Huijin , Zhang Wei , Ling Lianjie , Duan Wubiao , Liu Bo
Published: September 2017

The proposed electrons transfer mechanism for graphene well-wrapped UiO-66-NH2 octahedrons.
Synthesis of nanostructured graphite via molten salt reduction of CO2 and SO2 at a relatively low temperature
Authors: Chen Zhigang , Gu Yuxing , Hu Liangyou , Xiao Wei , Mao Xuhui , Zhu Hua , Wang Dihua
Published: September 2017

A low temperature graphitization process integrates SO2 and CO2 capture and reduction, promising a novel method to prepare graphite.
Trans Male Voice in the First Year of Testosterone Therapy: Make No Assumptions
Authors: Hancock Adrienne B. , Childs Kayla D. , Irwig Michael S.
Published: September 2017

Purpose

The purpose of this study was to prospectively examine changes in gender-related voice domain of pitch measured by fundamental frequency, function-related domains of vocal quality, range, and habitual pitch level and the self-perceptions of transmasculine people during their first year of testosterone treatment.

Method

Seven trans men received 2 voice assessments at baseline and 1 assessment at 3, 6, 9, and 12 months after starting treatment.

Results

Vocal quality measures varied between and within participants but were generally within normal limits throughout the year. Mean fundamental frequency (MF0) during reading decreased, although to variable extents and rates. Phonation frequency range shifted down the scale, although it increased in some participants and decreased in others. Considering MF0 and phonation frequency range together in a measure of habitual pitch level revealed that the majority of participants spoke using an MF0 that was low within their range compared with cisgender norms. Although the trans men generally self-reported voice masculinization, it was not correlated with MF0, frequency range, or habitual pitch level at any time point or with MF0 note change from baseline to 1 year of testosterone treatment, but correlations should be interpreted with caution due to the heterogeneous responses of the 7 participants.

Conclusion

In trans men, consideration of voice deepening in the context of objective and subjective measures of voice can reveal unique profiles and inform patient care.
Robust stock and bond allocation with end-of-horizon effects
Authors: Dziecichowicz Michael , Thiele Aurélie C.
Published: September 2017

We propose an approach to portfolio management over a finite time horizon that (i) does not require the precise knowledge of the underlying probability distributions, instead relying on range forecasts for the stock returns, and (ii) allows the fund manager to capture the degree of the investor’s risk aversion through a single, intuitive parameter called the budget of uncertainty. This budget represents the worst-case number of time periods with poor performance that the investor is willing to plan for. An application of this setting is target-date funds for pension fund management. We describe an efficient procedure to compute the dynamic allocation between (riskless) bonds and (riskier) stocks at each time period, and we illustrate the risk-to-time-horizon tradeoff on optimal allocation tables, which can easily be provided to fund participants to help them select their strategy. The proposed approach refines rules implemented by practitioners and provides an intuitive framework to incorporate risk in applications with end of horizon effects. In contrast with existing literature providing robust fund management approaches to mathematically sophisticated finance professionals, our goal is to provide a simple framework for less quantitative fund participants who seek to understand how stock return uncertainty and planned retirement date affect the optimal stock-vs-bond allocation in their portfolio. We extend our procedure to the case when the investor’s wealth is penalized for falling short of performance benchmarks across the time horizon. We also discuss the case where the manager can invest in multiple stocks. Numerical results are provided.
Characterization of a microwave-excited atmospheric-pressure argon plasma jet using two-parallel-wires transmission line resonator
Authors: Choi J. , Eom I. S. , Kim S. J. , Kwon Y. W. , Joh H. M. , Jeong B. S. , Chung T. H.
Published: September 2017

This paper presents a method to produce a microwave-excited atmospheric-pressure plasma jet (ME-APPJ) with argon. The plasma was generated by a microwave-driven micro-plasma source that uses a two-parallel-wire transmission line resonator (TPWR) operating at around 900 MHz. The TPWR has a simple structure and is easier to fabricate than coaxial transmission line resonator (CTLR) devices. In particular, the TPWR can sustain more stable ME-APPJ than the CTLR can because the gap between the electrodes is narrower than that in the CTLR. In experiments performed with an Ar flow rate from 0.5 to 8.0 L·min−1 and an input power from 1 to 6 W, the rotational temperature was determined by comparing the measured and simulated spectra of rotational lines of the OH band and the electron excitation temperature determined by the Boltzmann plot method. The rotational temperature obtained from OH(A-X) spectra was 700 K to 800 K, whereas the apparent gas temperature of the plasma jet remains lower than ∼325 K, which is compatible with biomedical applications. The electron number density was determined using the method based on the Stark broadening of the hydrogen Hβ line, and the measured electron density ranged from 6.5 × 1014 to 7.6 × 1014 cm−3. TPWR ME-APPJ can be operated at low flows of the working gas and at low power and is very stable and effective for interactions of the plasma with cells.
Multitarget search on complex networks: A logarithmic growth of global mean random cover time
Authors: Weng Tongfeng , Zhang Jie , Small Michael , Yang Ji , Bijarbooneh Farshid Hassani , Hui Pan
Published: September 2017

We investigate multitarget search on complex networks and derive an exact expression for the mean random cover time that quantifies the expected time a walker needs to visit multiple targets. Based on this, we recover and extend some interesting results of multitarget search on networks. Specifically, we observe the logarithmic increase of the global mean random cover time with the target number for a broad range of random search processes, including generic random walks, biased random walks, and maximal entropy random walks. We show that the logarithmic growth pattern is a universal feature of multi-target search on networks by using the annealed network approach and the Sherman-Morrison formula. Moreover, we find that for biased random walks, the global mean random cover time can be minimized, and that the corresponding optimal parameter also minimizes the global mean first passage time, pointing towards its robustness. Our findings further confirm that the logarithmic growth pattern is a universal law governing multitarget search in confined media.
Heteroepitaxial growth of tetragonal Mn2.7−xFexGa1.3 (0 ≤ x ≤ 1.2) Heusler films with perpendicular magnetic anisotropy
Authors: Kalache Adel , Markou Anastasios , Selle Susanne , Höche Thomas , Sahoo Roshnee , Fecher Gerhard H. , Felser Claudia
Published: September 2017

This work reports on the structural and magnetic properties of Mn2.7−xFexGa1.3 Heusler films with different Fe content x (0 ≤ x ≤ 1.2). The films were deposited heteroepitaxially on MgO single crystal substrates, by magnetron sputtering. Mn2.7−xFexGa1.3 films with the thickness of 35 nm were crystallized in a tetragonal D022 structure with (001) preferred orientation. Tunable magnetic properties were achieved by changing the Fe content x. Mn2.7−xFexGa1.3 thin films exhibit high uniaxial anisotropy Ku ≥ 1.4 MJ/m3, coercivity from 0.95 to 0.31 T, and saturation magnetization from 290 to 570 kA/m. The film with Mn1.6Fe1.1Ga1.3 composition shows high Ku of 1.47 MJ/m3 and energy product (BH)max of 37 kJ/m3 at room temperature. These findings demonstrate that Mn2.7−xFexGa1.3 films have promising properties for mid-range permanent magnet and spintronic applications.
Epitaxial thin films of Dirac semimetal antiperovskite Cu3PdN
Authors: Quintela C. X. , Campbell N. , Shao D. F. , Irwin J. , Harris D. T. , Xie L. , Anderson T. J. , Reiser N. , Pan X. Q. , Tsymbal E. Y. , Rzchowski M. S. , Eom C. B.
Published: September 2017

The growth and study of materials showing novel topological states of matter is one of the frontiers in condensed matter physics. Among this class of materials, the nitride antiperovskite Cu3PdN has been proposed as a new three-dimensional Dirac semimetal. However, the experimental realization of Cu3PdN and the consequent study of its electronic properties have been hindered due to the difficulty of synthesizing this material. In this study, we report fabrication and both structural and transport characterization of epitaxial Cu3PdN thin films grown on (001)-oriented SrTiO3 substrates by reactive magnetron sputtering and post-annealed in NH3 atmosphere. The structural properties of the films, investigated by x-ray diffraction and scanning transmission electron microscopy, establish single phase Cu3PdN exhibiting cube-on-cube epitaxy (001)[100]Cu3PdN||(001)[100]SrTiO3. Electrical transport measurements of as-grown samples show metallic conduction with a small temperature coefficient of the resistivity of 1.5 × 10−4 K−1 and a positive Hall coefficient. Post-annealing in NH3 results in the reduction of the electrical resistivity accompanied by the Hall coefficient sign reversal. Using a combination of chemical composition analyses and ab initio band structure calculations, we discuss the interplay between nitrogen stoichiometry and magneto-transport results in the framework of the electronic band structure of Cu3PdN. Our successful growth of thin films of antiperovskite Cu3PdN opens the path to further investigate its physical properties and their dependence on dimensionality, strain engineering, and doping.
High voltage performance of a dc photoemission electron gun with centrifugal barrel-polished electrodes
Authors: Hernandez-Garcia C. , Bullard D. , Hannon F. , Wang Y. , Poelker M.
Published: September 2017

The design and fabrication of electrodes for direct current (dc) high voltage photoemission electron guns can significantly influence their performance, most notably in terms of maximum achievable bias voltage. Proper electrostatic design of the triple-point junction shield electrode minimizes the risk of electrical breakdown (arcing) along the insulator-cable plug interface, while the electrode shape is designed to maintain <10 MV/m at the desired operating voltage aiming at little or no field emission once conditioned. Typical electrode surface preparation involves diamond-paste polishing by skilled personnel, requiring several weeks of effort per electrode. In this work, we describe a centrifugal barrel-polishing technique commonly used for polishing the interior surface of superconducting radio frequency cavities but implemented here for the first time to polish electrodes for dc high voltage photoguns. The technique reduced polishing time from weeks to hours while providing surface roughness comparable to that obtained with diamond-paste polishing and with unprecedented consistency between different electrode samples. We present electrode design considerations and high voltage conditioning results to 360 kV (∼11 MV/m), comparing barrel-polished electrode performance to that of diamond-paste polished electrodes. Tests were performed using a dc high voltage photogun with an inverted-geometry ceramic insulator design.
Interactions between coherent twin boundaries and phase transition of iron under dynamic loading and unloading
Authors: Wang Kun , Chen Jun , Zhang Xueyang , Zhu Wenjun
Published: September 2017

Phase transitions and deformation twins are constantly reported in many BCC metals under high pressure, whose interactions are of fundamental importance to understand the strengthening mechanism of these metals under extreme conditions. However, the interactions between twins and phase transition in BCC metals remain largely unexplored. In this work, interactions between coherent twin boundaries and α ↔ ε phase transition of iron are investigated using both non-equilibrium molecular dynamics simulations and the nudged elastic band method. Mechanisms of both twin-assisted phase transition and reverse phase transition are studied, and orientation relationships between BCC and HCP phases are found to be 111¯BCC||1¯21¯0HCP and 11¯0BCC||0001HCP for both cases. The twin boundary corresponds to 101¯0HCP after the phase transition. It is amazing that the reverse transition seems to be able to “memorize” and recover the initial BCC twins. The memory would be partly lost when plastic slips take place in the HCP phase before the reverse transition. In the recovered initial BCC twins, three major twin spacings are observed, which are well explained in terms of energy barriers of transition from the HCP phase to the BCC twin. Besides, the variant selection rule of the twin assisted phase transition is also discussed. The results of present work could be expected to give some clues for producing ultra-fine grain structures in materials exhibiting martensitic phase transition.
Comparison of superhydrophobic drag reduction between turbulent pipe and channel flows
Authors: Im Hyung Jae , Lee Jae Hwa
Published: September 2017

It has been known over several decades that canonical wall-bounded internal flows of a pipe and channel share flow similarities, in particular, close to the wall due to the negligible curvature effect. In the present study, direct numerical simulations of fully developed turbulent pipe and channel flows are performed to investigate the influence of the superhydrophobic surfaces (SHSs) on the turbulence dynamics and the resultant drag reduction (DR) of the flows under similar conditions. SHSs at the wall are modeled in spanwise-alternating longitudinal regions with a boundary with no-slip and shear-free conditions, and the two parameters of the spanwise periodicity (P/δ) and SHS fraction (GF) within a pitch are considered. It is shown, in agreement with previous investigations in channels, that the turbulent drag for the pipe and channel flows over SHSs is continuously decreased with increases in P/δ and GF. However, the DR rate in the pipe flows is greater than that in the channel flows with an accompanying reduction of the Reynolds stress. The enhanced performance of the DR for the pipe flow is attributed to the increased streamwise slip and weakened Reynolds shear stress contributions. In addition, a mathematical analysis of the spanwise mean vorticity equation suggests that the presence of a strong secondary flow due to the increased spanwise slip of the pipe flows makes a greater negative contribution of advective vorticity transport than the channel flows, resulting in a higher DR value. Finally, an inspection of the origin of the mean secondary flow in turbulent flows over SHSs based on the spatial gradients of the turbulent kinetic energy demonstrates that the secondary flow is both driven and sustained by spatial gradients in the Reynolds stress components, i.e., Prandtl’s secondary flow of the second kind.
Improved scatter correction with factor analysis for planar and SPECT imaging
Authors: Knoll Peter , Rahmim Arman , Gültekin Selma , Šámal Martin , Ljungberg Michael , Mirzaei Siroos , Segars Paul , Szczupak Boguslaw
Published: September 2017

Quantitative nuclear medicine imaging is an increasingly important frontier. In order to achieve quantitative imaging, various interactions of photons with matter have to be modeled and compensated. Although correction for photon attenuation has been addressed by including x-ray CT scans (accurate), correction for Compton scatter remains an open issue. The inclusion of scattered photons within the energy window used for planar or SPECT data acquisition decreases the contrast of the image. While a number of methods for scatter correction have been proposed in the past, in this work, we propose and assess a novel, user-independent framework applying factor analysis (FA). Extensive Monte Carlo simulations for planar and tomographic imaging were performed using the SIMIND software. Furthermore, planar acquisition of two Petri dishes filled with 99mTc solutions and a Jaszczak phantom study (Data Spectrum Corporation, Durham, NC, USA) using a dual head gamma camera were performed. In order to use FA for scatter correction, we subdivided the applied energy window into a number of sub-windows, serving as input data. FA results in two factor images (photo-peak, scatter) and two corresponding factor curves (energy spectra). Planar and tomographic Jaszczak phantom gamma camera measurements were recorded. The tomographic data (simulations and measurements) were processed for each angular position resulting in a photo-peak and a scatter data set. The reconstructed transaxial slices of the Jaszczak phantom were quantified using an ImageJ plugin. The data obtained by FA showed good agreement with the energy spectra, photo-peak, and scatter images obtained in all Monte Carlo simulated data sets. For comparison, the standard dual-energy window (DEW) approach was additionally applied for scatter correction. FA in comparison with the DEW method results in significant improvements in image accuracy for both planar and tomographic data sets. FA can be used as a user-independent approach for scatter correction in nuclear medicine.
Numerical sensitivity analysis of a variational data assimilation procedure for cardiac conductivities
Authors: Barone Alessandro , Fenton Flavio , Veneziani Alessandro
Published: September 2017

An accurate estimation of cardiac conductivities is critical in computational electro-cardiology, yet experimental results in the literature significantly disagree on the values and ratios between longitudinal and tangential coefficients. These are known to have a strong impact on the propagation of potential particularly during defibrillation shocks. Data assimilation is a procedure for merging experimental data and numerical simulations in a rigorous way. In particular, variational data assimilation relies on the least-square minimization of the misfit between simulations and experiments, constrained by the underlying mathematical model, which in this study is represented by the classical Bidomain system, or its common simplification given by the Monodomain problem. Operating on the conductivity tensors as control variables of the minimization, we obtain a parameter estimation procedure. As the theory of this approach currently provides only an existence proof and it is not informative for practical experiments, we present here an extensive numerical simulation campaign to assess practical critical issues such as the size and the location of the measurement sites needed for in silico test cases of potential experimental and realistic settings. This will be finalized with a real validation of the variational data assimilation procedure. Results indicate the presence of lower and upper bounds for the number of sites which guarantee an accurate and minimally redundant parameter estimation, the location of sites being generally non critical for properly designed experiments. An effective combination of parameter estimation based on the Monodomain and Bidomain models is tested for the sake of computational efficiency. Parameter estimation based on the Monodomain equation potentially leads to the accurate computation of the transmembrane potential in real settings.
Low-temperature magnetic behavior of nanostructured ferrite compositions prepared by plasma spraying
Authors: Lepeshev A. A. , Ushakov A. V. , Karpov I. V.
Published: September 2017

Peculiarities of low-temperature behavior of the magnetic properties of disordered spinel ferrites, prepared by means of dilution with the P2O5 amorphizing agent and by rapid quenching, were investigated. A sharp increase in the saturation magnetization σS, of ferrite compositions (1-x)MeFe2O4·xP2O5 (where Me is Ni, Fe, Mn, etc.), was observed at temperatures T < 80 K. It was established that the temperature dependences of σS and χ−1 (where χ is the magnetic susceptibility) of the nickel ferrite composition (x = 0.6) have an extremum at T = 11 K. In this case, the effect of “memory” is observed for σS(T), which represents the dependence of σS (T = 4.2 K) on the magnitude of the magnetic field in which cooling was carried out. The asymptotic Curie temperature was determined by extrapolation of the linear part of the χ−1(T) dependence and found to be equal to −150 K. We present an analysis of the observed dependences from the viewpoint of a complex magnetic state, combining the features of the near antiferromagnetic and ferrimagnetic boundary-surface spin ordering.
Photocurrent and photoluminescence characteristics of AlGaAs/GaAs double-heterostructures with a pair of two-dimensional electron and hole channels
Authors: Kushida T. , Ohmori M. , Sakaki H.
Published: September 2017

AlGaAs/GaAs/AlGaAs double-heterostructures having two-dimensional electron and hole channels at the respective interfaces are studied by measuring their photocurrent and photoluminescence characteristics. Under the weak photoexcitation, it is found that photo-generated electrons and holes are driven by a built-in electric field between the two channels and flow out mostly as a photocurrent to the respective electrodes, making the photoluminescence negligibly small. When the excitation reaches a certain level, some of photo-generated electrons and holes accumulate in each channel and weaken the built-in field, leading to an exponential increase in photoluminescence or the radiative recombination of electrons and holes. When the excitation gets strong, photo-generated carriers are lost mostly in the form of photoluminescence, resulting in the saturation of photocurrent. A theoretical model to explain these findings is presented. A possibility of using this type of study to clarify operating mechanisms of super-junction devices is suggested.
On the interplay of morphology and electronic conductivity of rotationally spun carbon fiber mats
Authors: Opitz Martin , Go Dennis , Lott Philipp , Müller Sandra , Stollenwerk Jochen , Kuehne Alexander J. C. , Roling Bernhard
Published: September 2017

Carbon-based materials are used as electrode materials in a wide range of electrochemical applications, e.g., in batteries, supercapacitors, and fuel cells. For these applications, the electronic conductivity of the materials plays an important role. Currently, porous carbon materials with complex morphologies and hierarchical pore structures are in the focus of research. The complex morphologies influence the electronic transport and may lead to an anisotropic electronic conductivity. In this paper, we unravel the influence of the morphology of rotationally spun carbon fiber mats on their electronic conductivity. By combining experiments with finite-element simulations, we compare and evaluate different electrode setups for conductivity measurements. While the “bar-type method” with two parallel electrodes on the same face of the sample yields information about the intrinsic conductivity of the carbon fibers, the “parallel-plate method” with two electrodes on opposite faces gives information about the electronic transport orthogonal to the faces. Results obtained for the van-der-Pauw method suggest that this method is not well suited for understanding morphology-transport relations in these materials.
Transparent broadband metamaterial absorber based on resistive films
Authors: Sheokand Harsh , Ghosh Saptarshi , Singh Gaganpreet , Saikia Mondeep , Srivastava Kumar Vaibhav , Ramkumar J. , Anantha Ramakrishna S.
Published: September 2017

In this paper, an optically transparent metamaterial with broadband absorption is presented theoretically and demonstrated experimentally. The design comprises of structures made of resistive films of indium-tin-oxide and the metamaterial exhibits over 10 dB absorption in the frequency range of 6.06–14.66 GHz. The novelty of the structure lies in its large absorption bandwidth along with a reduced thickness and optical transparency compared to broadband absorbers reported earlier. Besides, the proposed design is polarization-insensitive and gives rise to angular independent absorption for both transverse electric and transverse magnetic polarizations. The absorption mechanism in the structure has been studied by deriving an equivalent circuit model as well as analyzing several design parameters. Finally, a prototype of the proposed structure has been fabricated and measured, which shows good agreement with the simulated results.
The mean random cover time for various search strategies follows a logarithmic, versus linear, growth pattern
Authors: Hendricks-Sturrup Rachele
Published: September 2017

Researchers describe a natural logarithmic growth pattern that slowly increases in proportion to the number of search targets in random information search processes.
The Islamic State’s information warfare
Authors: Siegel Alexandra A. , Tucker Joshua A.
Published: September 2017

How successful is the Islamic State’s online strategy? To what extent does the organization achieve its goals of attracting a global audience, broadcasting its military successes, and marketing the Caliphate? Using Twitter and YouTube search data, collected throughout 2015 and early 2016, we assess how suspected ISIS accounts, sympathizers, and opponents behave across two social media platforms, offering key insights into the successes and limitations of ISIS’s information warfare strategy. Analyzing the tweet content and metadata from 16,364 suspected ISIS accounts, we find that a core network of ISIS Twitter users are producing linguistically diverse narratives, touting battlefield victories and depicting utopian life in the Caliphate. Furthermore, a dataset of over 70 million tweets, as well as analysis YouTube search data, indicates that although pro-ISIS content spreads globally and remains on message, it is far less prolific than anti-ISIS content. However, this anti-ISIS content is not necessarily anti-extremist or aligned with Western policy goals.
Covert co-activation of bilinguals’ non-target language
Authors: Shook Anthony , Marian Viorica
Published: September 2017

When listening to spoken language, bilinguals access words in both of their languages at the same time; this co-activation is often driven by phonological input mapping to candidates in multiple languages during online comprehension. Here, we examined whether cross-linguistic activation could occur covertly when the input does not overtly cue words in the non-target language. When asked in English to click an image of a duck, English-Spanish bilinguals looked more to an image of a shovel than to unrelated distractors, because the Spanish translations of the words duck and shovel (pato and pala, respectively) overlap phonologically in the non-target language. Our results suggest that bilinguals access their unused language, even in the absence of phonologically overlapping input. We conclude that during bilingual speech comprehension, words presented in a single language activate translation equivalents, with further spreading activation to unheard phonological competitors. These findings support highly interactive theories of language processing.
Mechanical stability of boron-based coatings grown on Incoloy 909 superalloy by thermochemical diffusion
Authors: Gaona-Martínez Mauro J. , Alonso-Saavedra Omar F. , Ramírez-Ramírez Javier H. , Castillo-Elizondo Jaime A. , Zapata-Hernández Oscar , Pérez-González Francisco A. , Gallardo-Hernández Ezequiel A. , Colás Rafael , Garza-Montes-De-Oca Nelson F.
Published: September 2017

Incoloy 909 superalloy was treated at 950°C to form coatings of different chemical composition by thermochemical diffusion. Packing of the samples in reactive powders lead to the formation of iron borides (Fe2B and FeB) together with nickel boride, NiB, and nickel silicide, Ni2Si, on the surface of the alloy depending on the exposure time. X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy analyses suggest that growth of the coatings is controlled by diffusion of reactive species into the metal structure. Microabrasion wear resistance of the coated specimens was studied at 1 N load for a fixed sliding speed of 0.11 m s−1 and it was compared against uncoated samples of the alloy. It was found that coating the alloy for 12 and 20 h increased the hardness of the alloy and therefore its wear resistance.
Winners and losers as mangrove, coral and seagrass ecosystems respond to sea-level rise in Solomon Islands
Authors: Albert Simon , Saunders Megan I , Roelfsema Chris M , Leon Javier X , Johnstone Elizabeth , Mackenzie Jock R , Hoegh-Guldberg Ove , Grinham Alistair R , Phinn Stuart R , Duke Norman C , Mumby Peter J , Kovacs Eva , Woodroffe Colin D
Published: September 2017

A 2007 earthquake in the western Solomon Islands resulted in a localised subsidence event in which sea level (relative to the previous coastal settings) rose approximately 30–70 cm, providing insight into impacts of future rapid changes to sea level on coastal ecosystems. Here, we show that increasing sea level by 30–70 cm can have contrasting impacts on mangrove, seagrass and coral reef ecosystems. Coral reef habitats were the clear winners with a steady lateral growth from 2006–2014, yielding a 157% increase in areal coverage over seven years. Mangrove ecosystems, on the other hand, suffered the largest impact through a rapid dieback of 35% (130 ha) of mangrove forest in the study area after subsidence. These forests, however, had partially recovered seven years after the earthquake albeit with a different community structure. The shallow seagrass ecosystems demonstrated the most dynamic response to relative shifts in sea level with both losses and gains in areal extent at small scales of 10–100 m. The results of this study emphasize the importance of considering the impacts of sea-level rise within a complex landscape in which winners and losers may vary over time and space.
Reply to Comment on ‘High-income does not protect against hurricane losses’
Authors: Geiger Tobias , Frieler Katja , Levermann Anders
Published: September 2017

Recently a multitude of empirically derived damage models have been applied to project future tropical cyclone (TC) losses for the United States. In their study (Geiger et al 2016 Environ. Res. Lett.
11 084012) compared two approaches that differ in the scaling of losses with socio-economic drivers: the commonly-used approach resulting in a sub-linear scaling of historical TC losses with a nation’s affected gross domestic product (GDP), and the disentangled approach that shows a sub-linear increase with affected population and a super-linear scaling of relative losses with per capita income. Statistics cannot determine which approach is preferable but since process understanding demands that there is a dependence of the loss on both GDP per capita and population, an approach that accounts for both separately is preferable to one which assumes a specific relation between the two dependencies. In the accompanying comment, Rybski et al argued that there is no rigorous evidence to reach the conclusion that high-income does not protect against hurricane losses. Here we affirm that our conclusion is drawn correctly and reply to further remarks raised in the comment, highlighting the adequateness of our approach but also the potential for future extension of our research.
Facilitated Extinction Training to Improve Pharmacotherapy for Smoking Cessation: A Pilot Feasibility Trial
Authors: Brandon Thomas H , Unrod Marina , Drobes David J , Sutton Steven K , Hawk Larry W , Simmons Vani N , Brandon Karen O , Roetzheim Richard G , Meltzer Lauren R , Miller Ralph R , Cahill Shawn P
Published: September 2017

Introduction

Varenicline reduces smoking satisfaction during the pre-cessation run-in period, which may contribute to extinction of cravings and smoking behavior. Research indicates that efficacy is enhanced when the run-in period is increased from 1 to 4 weeks, providing a longer extinction opportunity. We hypothesized that efficacy could be further enhanced by harnessing basic and applied research on extinction. We developed a pre-cessation extinction-facilitating intervention and tested its feasibility in a pilot trial.

Methods

The facilitated extinction (FE) intervention comprised brief counseling and workbook-recommending strategies to maximize extinction processes during the run-in, including instructions to smoke at a normal rate across contexts and cues, and use of an extinction cue to enhance generalization. Participants were randomly assigned to one of three varenicline interventions: standard (1-week run-in), extended (4-week run-in), and extended + FE. Interventions were delivered prior to the target quit date (TQD). Assessments were conducted in weeks 1 and 4 pre-TQD and 1 and 3 months post-TQD, with focus on feasibility indices.

Results

Recruitment and retention goals were met (N = 58). Treatment satisfaction was high across groups. The majority of FE participants adhered to instructions and maintained their usual smoking rate during the run-in period. Greater decreases in craving and smoking satisfaction were observed among participants in both extended groups versus the standard group (p < .005).

Conclusions

Feasibility was demonstrated. Participants adhered to the FE intervention, thereby optimizing the number and variety of extinction trials. Findings support testing the novel FE smoking cessation intervention in a fully powered trial.

Implications

This study expands the research on the clinical benefits of extending the pre-cessation run-in period of varenicline. It introduces the hypothesis that further benefit might be achieved by translating basic behavioral research, as well as cue-exposure research and therapy for other disorders, to improve the extinction and generalization processes thought to underlie much of varenicline’s effect. A FE intervention was developed and found acceptable to smokers and feasible to implement in a research setting. The study sets the stage for a subsequent randomized controlled trial.
Posterior Amorphous Corneal Dystrophy Associated With Keratoglobus: A Case Report
Authors: Fay Jonathan , Herzlich Alexandra A. , Florakis George J.
Published: September 2017

Purpose:

Posterior amorphous corneal dystrophy (PACD) is a rare disorder characterized by sheet-like opacification of the posterior corneal stroma, corneal thinning, and decreased corneal curvature. It is not known to be associated with progressive corneal ectasia. In this report, we examine the course of a patient with PACD who developed bilateral keratoglobus-type corneal ectasia.

Methods:

The clinical history of a single patient is reviewed from birth through age 15. Visual acuity, refraction, ultrasound pachymetry, anterior segment optical coherence tomography, corneal topography, and corneal tomography are presented.

Results:

The patient was noted to have bilateral cloudy corneas at birth. Congenital infection, metabolic disease, and glaucoma were ruled out. Anterior segment optical coherence tomography demonstrated posterior stromal opacification typical of PACD. Over time, the patient progressed from best uncorrected visual acuity of 20/20-2 OD and 20/25-3 OS to PROSE lens-corrected visual acuity of 20/30-3 OD and 20/30-3 OS. Central corneal thinness progressed from 491 to 408 μm in the right eye and from 505 to 389 μm in the left eye. Steepening in corneal axial/sagittal curvature developed in both eyes beginning inferiorly then involving the corneas diffusely.

Conclusions:

In this case report, we illustrate progressive corneal ectasia in a patient with PACD. Although both conditions may represent changes in the structure and integrity of corneal collagen, whether an association exists between the 2 conditions is unknown.
“Bubble-in-the-Roll” Technique Using the Endoject DMEK Injector: Influence of the Air Bubble on Endothelial Cell Loss
Authors: Akbaba Yasemin , Weller Julia M. , Rössler Kathrin , Armitage W. John , Schlötzer-Schrehardt Ursula , Kruse Friedrich E. , Tourtas Theofilos
Published: September 2017

Purpose:

To evaluate the impact of the air bubble on endothelial cell loss using the “bubble-in-the-roll” technique during Descemet membrane endothelial keratoplasty (DMEK).

Methods:

Twenty DMEK grafts not suitable for transplantation were manually prepared from organ-cultured corneoscleral discs and injected into culture media using the Endoject DMEK injector (Medicel AG, Wolfhalden, Switzerland). Based on the injection method, the grafts were divided into 2 groups: In group A (n = 10), a small air bubble was placed inside the graft roll while it was in the injector. In group B (n = 10), the grafts were injected without an air bubble inside the graft roll. Main outcome measures included endothelial cell density (ECD) after graft stripping and graft injection.

Results:

There were no statistically significant differences between groups A and B in donor age, storage duration, and donor ECD. ECD decreased from 1929 ± 145 cells/mm2 to 1796 ± 303 cells/mm2 after graft stripping in group A and from 1801 ± 226 cells/mm2 to 1709 ± 290 cells/mm2 in group B. ECD after graft injection further decreased to 1683 ± 291 cells/mm2 in group A and to 1651 ± 292 cells/mm2 in group B. Endothelial cell loss after graft stripping and graft injection was not statistically significant between groups A and B (P = 0.29 and P = 1, respectively).

Conclusions:

The bubble-in-the-roll technique for injection and unfolding of the graft is a safe method for graft delivery into the anterior chamber guaranteeing orientation of the graft without harming the endothelium.
Meibomian Gland Dysfunction Associated With Periocular Radiotherapy
Authors: Woo Young Jun , Ko JaeSang , Ji Yong Woo , Kim Tae-im , Yoon Jin Sook
Published: September 2017

Purpose:

To investigate the influence of periocular radiotherapy on meibomian glands.

Methods:

We evaluated 28 patients (40 eyes) who received radiotherapy (RT group) for conjunctival or orbital lymphoma and 30 age-matched control subjects (60 eyes). Subjects underwent slit-lamp examination of the eyelids, Schirmer test, meibography, and evaluation of tear film breakup time (TBUT), Ocular Surface Disease Index (OSDI) scores, meibomian glands evaluation (meiboscore, meibum expressibility, and lid margin abnormality scores), and tear film lipid layer thickness using an ocular surface interferometer. These parameters were compared between subjects in the RT and control groups.

Results:

Meiboscores as well as meibum expressibility and OSDI scores in the RT group were significantly higher compared with those in the control group (1.6 ± 0.9 vs. 0.4 ± 0.6, 1.6 ± 1.0 vs. 0.2 ± 0.4, and 48.1 ± 21.4 vs. 6.2 ± 4.4, respectively, P < 0.001, all), whereas the Schirmer value (9.2 ± 5.1 vs. 12.3 ± 5.2, P = 0.004), TBUT (4.2 ± 2.5 vs. 6.4 ± 2.6, P = 0.001), and lipid layer thickness (61.0 ± 29.3 vs. 85.2 ± 20.0, P < 0.001) in the RT group were lower compared with those in the control group. The percentage of meibomian gland dropout was significantly correlated with age (P = 0.025) and total radiation dose (P = 0.012), regardless of the target location of irradiation. Even low-dose irradiated eyes (<30 Gy) exhibited significantly higher meiboscores (P < 0.001) and shorter TBUT (P = 0.005) compared with control eyes.

Conclusions:

Eyes that received periocular radiotherapy exhibited relatively high tear film instability induced by meibomian gland dysfunction, contributing to the high severity of dry eye symptoms.
Endocrine Mucin-Producing Sweat Gland Carcinoma of the Eyelid Associated With Mucinous Adenocarcinoma
Authors: Charles Norman C. , Proia Alan D. , Lo Christopher
Published: September 2017

Endocrine mucin-producing sweat gland carcinoma, a rare, low-grade neoplasm with predilection for the eyelids, has been posited as a precursor to invasive mucinous adenocarcinoma. Endocrine mucin-producing sweat gland carcinoma and its concurrence with mucinous adenocarcinoma have received little attention in the ophthalmic literature. The combination of the 2 histologic patterns parallels endocrine ductal carcinoma in situ of the breast and its transition to Type B invasive mucinous carcinoma. The authors describe a 59-year-old man who developed a tumor of the right upper eyelid showing endocrine mucin-producing sweat gland carcinoma in the outer dermis and extensive mucinous carcinoma in the deeper tissue. Immunohistochemical analysis showed positivity for endocrine markers chromogranin, synaptophysin, CD56, estrogen, and progesterone in each histologic component of the tumor. This research was conducted in conformity with the Helsinki Declaration and HIPPA regulations.
Multiple Shiny Papules With Central Umbilication on the Back
Authors: Nguyen Catherine M. , Jacob Sharon E.
Published: September 2017

Teledermatology is a term to describe the provision of dermatologic medical services through telecommunication technology. This is a teledermatology case of multiple shiny papules with central umbilication on the back.
Biomineralized Conductive PEDOT:PSS-Coated PLA/PHBV/HA Nanofibrous Membranes
Authors: Hassan Mohd Izzat , Masnawi Noor Nabilah , Sultana Naznin
Published: September 2017

Conductive materials are potential candidates for developing bone tissue engineering scaffolds as they are nontoxic and can enhance bone tissue regeneration. Their bioactivity can be enhanced by depositing biomineralization in simulated body fluid (SBF). In the current study, a composite electrospun membrane made up of poly(lactic) acid, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and hydroxyapatite was fabricated using an electrospinning method. The fabricated membranes were dip-coated with a conductive polymer solution, poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate), to induce conductivity. Characterization of the membranes based on characteristics such as morphology, chemical bonding, and wettability was conducted using scanning electron microscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and contact angle measurement. From the results, biomineralization of both coated and noncoated composite membranes was observed on the surface of nanofibers after 21 days in SBF. The membranes provide a superhydrophilic surface as shown by the contact angle. In conclusion, this biomimetic electrospun composite membrane could be used to further support cell growth for bone tissue engineering application.
Predictors of Pancreatic Cancer–Associated Weight Loss and Nutritional Interventions
Authors: Nemer Laura , Krishna Somashekar G. , Shah Zarine K. , Conwell Darwin L. , Cruz-Monserrate Zobeida , Dillhoff Mary , Guttridge Denis C. , Hinton Alice , Manilchuk Andrei , Pawlik Timothy M. , Schmidt Carl R. , Talbert Erin E. , Bekaii-Saab Tanios , Hart Phil A.
Published: September 2017

Objectives

Pancreatic ductal adenocarcinoma (PDAC) is often accompanied by weight loss. We sought to characterize factors associated with weight loss and observed nutritional interventions, as well as define the effect of weight loss on survival.

Methods

Consecutive subjects diagnosed with PDAC (N = 123) were retrospectively evaluated. Univariate analysis was used to compare subjects with and without substantial (>5%) weight loss. Multivariate logistic regression was performed to identify factors associated with weight loss, and survival analyses were performed using Kaplan-Meier curves and Cox survival models.

Results

Substantial weight loss at diagnosis was present in 71.5% of subjects and was independently associated with higher baseline body mass index, longer symptom duration, and increased tumor size. Recommendations for nutrition consultation and pancreatic enzyme replacement therapy occurred in 27.6% and 36.9% of subjects, respectively. Weight loss (>5%) was not associated with worse survival on multivariate analysis (hazard ratio, 1.32; 95% confidence interval, 0.76–2.30), unless a higher threshold (>10%) was used (hazard ratio, 1.77; 95% confidence interval, 1.09–2.87).

Conclusions

Despite the high prevalence of weight loss at PDAC diagnosis, there are low observed rates of nutritional interventions. Weight loss based on current criteria for cancer cachexia is not associated with poor survival in PDAC.
Diagnosing Chronic Pancreatitis
Authors: Issa Yama , van Santvoort Hjalmar C. , van Dieren Susan , Besselink Marc G. , Boermeester Marja A. , Ahmed Ali Usama
Published: September 2017

Objectives

This study aims to compare the M-ANNHEIM, Büchler, and Lüneburg diagnostic tools for chronic pancreatitis (CP).

Methods

A cross-sectional analysis of the development of CP was performed in a prospectively collected multicenter cohort including 669 patients after a first episode of acute pancreatitis. We compared the individual components of the M-ANNHEIM, Büchler, and Lüneburg tools, the agreement between tools, and estimated diagnostic accuracy using Bayesian latent-class analysis.

Results

A total of 669 patients with acute pancreatitis followed-up for a median period of 57 (interquartile range, 42–70) months were included. Chronic pancreatitis was diagnosed in 50 patients (7%), 59 patients (9%), and 61 patients (9%) by the M-ANNHEIM, Lüneburg, and Büchler tools, respectively. The overall agreement between these tools was substantial (κ = 0.75). Differences between the tools regarding the following criteria led to significant changes in the total number of diagnoses of CP: abdominal pain, recurrent pancreatitis, moderate to marked ductal lesions, endocrine and exocrine insufficiency, pancreatic calcifications, and pancreatic pseudocysts. The Büchler tool had the highest sensitivity (94%), followed by the M-ANNHEIM (87%), and finally the Lüneburg tool (81%).

Conclusions

Differences between diagnostic tools for CP are mainly attributed to presence of clinical symptoms, endocrine insufficiency, and certain morphological complications.