bluuebunny/crossref_metadata_2025 huggingface dataset:
Whistler modes in highly nonuniform magnetic fields. II. Propagation in three dimensions
Authors: Stenzel R. L. , Urrutia J. M.
Published: August 2018

In a large laboratory plasma, the properties of whistler modes are investigated in highly nonuniform magnetic fields. In an extension to previous measurements in two dimensions (2D), the present work shows new phenomena such as wave splitting in the third dimension and shedding of cross-field helicon-like modes. Three-dimensional (3D) data also permit the correct calculations of the field derivatives (∇⋅, ∇×), helicity density (J ⋅ B), Hall electric fields, phase and energy flow, and out-of-plane field structures, which are not visible from 2D data. Novel findings are the loss of the angular momentum of an m = 1 helicon mode, the splitting of a single wave packet into two wave packets in the direction of the loop axis, and the shedding of perpendicular whistler modes with angular momentum. The 3D effects cannot be explained by nonuniformities in the density and the 2D ambient magnetic field B0. They may arise from the conservation of orbital angular momentum whose direction changes along a curved magnetic field. It results in a precessional motion which creates asymmetries in the third dimension. Further effects are the interference of oppositely propagating helicon modes on circular field lines which creates linear polarization near the conjugate point of the antenna. Detached whistler modes are excited in the oscillating near-zone field. The waves propagate nearly perpendicular to the ambient field. The field polarization is right-hand circular around the oblique wave vector k but not around B0. Since the wave field is force-free the wave magnetic field lines form twisted field lines or writhed flux tubes. From streamlines of hodogram normals, it is shown that the wave exhibits a helical phase flow similar to helicon modes. These observations show the complexity of whistler modes in nonuniform magnetic fields, even under the simplest conditions of a uniform, unbounded plasma and linear waves. The results may be of interest to other laboratory plasmas and space plasmas in nonuniform magnetic fields. Meaningful comparisons require 3D field data which are rarely available.
Effects of collision on the time-independent states of a non-neutral plasma diode
Authors: Pramanik Sourav , Kuznetsov Victor I. , Chakrabarti Nikhil
Published: August 2018

A theoretical investigation is presented on the steady states of a planar plasma diode where static ions uniformly occupy the inter-electrode region. A cold and purely monochromatic electron beam is injected from the emitter plate, and the emitted electrons are carried to the collector plate through the uniform background of stationary ions. It is considered that the electrons suffer collisions with the other particles (with ions or neutral atoms) during its transportation through the inter-electrode gap. The effects of collisions are incorporated through a simplified one-dimensional model. With the help of Lagrangian description of fluid-Maxwell's equations, time-independent states are explored for arbitrary values of the neutralization parameter. Using the emitter electric field as a characteristic parameter, the steady-state solutions are categorized into “Bursian” and “Non-Bursian” branches in “emitter electric field vs diode gap” parametric space. The Non-Bursian solutions are found to be very sensitive to the dissipative term as they only exist for small, non-zero values of the normalized collision-frequency.
Development of new platforms for hydrodynamic instability and asymmetry measurements in deceleration phase of indirectly driven implosions on NIF
Authors: Pickworth L. A. , Hammel B. A. , Smalyuk V. A. , Robey H. F. , Tommasini R. , Benedetti L. R. , Berzak Hopkins L. , Bradley D. K. , Dayton M. , Felker S. , Field J. E. , Haan S. W. , Haid B. , Hatarik R. , Hartouni E. , Holunga D. , Hoppe M. , Izumi N. , Johnson S. , Khan S. , Kohut T. , Lahmann B. , Landen O. L. , LePape S. , MacPhee A. G. , Marley E. , Meezan N. B. , Milovich J. , Nagel S. R. , Nikroo A. , Pak A. E. , Petrasso R. , Remington B. A. , Rice N. G. , Scott H. A. , Springer P. T. , Stadermann M. , Walters C. , Widmann K. , Hsing W. W.
Published: August 2018

Hydrodynamic instabilities and asymmetries are a major obstacle in the quest to achieve ignition at the National Ignition Facility (NIF) as they cause pre-existing capsule perturbations to grow and ultimately quench the fusion burn in experiments. This paper reviews the development of two new experimental techniques to measure high-mode instabilities and low-mode asymmetries in the deceleration phase of indirect drive inertial confinement fusion implosions. In the first innovative technique, self-emission from the hot spot was enhanced with an argon dopant to “self-backlight” the shell in-flight, imaging the perturbations in the shell near peak velocity. Experiments with pre-imposed two-dimensional perturbations showed hydrodynamic instability growth of up to 7000× in areal density. These experiments discovered unexpected three-dimensional structures originating from the capsule support structures. These new 3-D structures became one of the primary concerns for the indirect drive ICF program that requires their origin to be understood and their impact mitigated. In a second complementary technique, the inner surface of the decelerating shell was visualized in implosions using x-ray emission of a high-Z dopant added to the inner surface of the capsule. With this technique, low mode asymmetry and high mode perturbations, including perturbations seeded by the gas fill tube and capsule support structure, were quantified near peak compression. Using this doping method, the role of perturbations and radiative losses from high atomic number materials on neutron yield was quantified.
One-transistor one-resistor (1T1R) cell for large-area electronics
Authors: Ghenzi N. , Rozenberg M. , Pietrobon L. , Llopis R. , Gay R. , Beltrán M. , Knez M. , Hueso L. , Stoliar P.
Published: August 2018

We developed a one-transistor one-resistor cell composed of one TiO2-based resistive switching (RS) device and one ZnO-based thin-film transistor (TFT). We study the electric characteristics of each component individually, and their interplay when both work together. We explored the direct control of bipolar RS devices, using our TFTs to drive current in both directions. We also report striking power implications when we swap the terminals of the RS device. The target of our work is the introduction of RS devices in large-area electronic (LAE) circuits. In this context, RS devices can be beneficial regarding functionality and energy consumption, when compared to other ways to introduce memory cells in LAE circuits.
Oxygen-vacancy-induced reversible control of ferroelectric polarization in Ba4Eu2Fe2Nb8O30 ceramics
Authors: Hong Jiang Sheng , Huang Yu Hui , Wu Yong Jun , Fu Mao Sen , Li Juan , Liu Xiao Qiang
Published: August 2018

Ba4Eu2Fe2Nb8O30 ceramics with a tetragonal tungsten bronze structure were synthesized under different sintering and annealing conditions. The maximum polarization of air-sintered samples decreased from 4.0 μC/cm2 to 3.6 μC/cm2 after annealing in an oxygen atmosphere. In contrast, the maximum polarization of oxygen-sintered samples improved from 3.5 μC/cm2 to 7.0 μC/cm2 after annealing in a nitrogen atmosphere. A reversible enhancement of remanent polarization (0.2 μC/cm2) induced by oxygen vacancies was also detected by the positive up negative down method. This reversible control of ferroelectric polarization was assumed to be associated with the structure modulation induced by oxygen vacancies. To prove this, selected area electron diffraction patterns were studied. The results showed that the oxygen vacancies would influence the direction of O-octahedral tilting and promote the commensurate modulation in Ba4Eu2Fe2Nb8O30, which contributed to the enhanced ferroelectric properties.
Steady-state reaction rate of diffusion-controlled reactions in sheets
Authors: Grebenkov Denis S. , Krapf Diego
Published: August 2018

In many biological situations, a species arriving from a remote source diffuses in a domain confined between two parallel surfaces until it finds a binding partner. Since such a geometric shape falls in between two- and three-dimensional settings, the behavior of the macroscopic reaction rate and its dependence on geometric parameters are not yet understood. Modeling the geometric setup by a capped cylinder with a concentric disk-like reactive region on one of the lateral surfaces, we provide an exact semi-analytical solution of the steady-state diffusion equation and compute the diffusive flux onto the reactive region. We explore the dependence of the macroscopic reaction rate on the geometric parameters and derive asymptotic results in several limits. Using the self-consistent approximation, we also obtain a simple fully explicit formula for the reaction rate that exhibits a transition from two-dimensional to three-dimensional behavior as the separation distance between lateral surfaces increases. Biological implications of these results are discussed.
Effects of kinematic parameters on three-dimensional flapping wing at low Reynolds number
Authors: Han Jiakun , Yuan Zongjing , Chen Gang
Published: August 2018

In nature, creatures such as birds, insects, and fish have excellent flight and mobility capabilities. The prominent flight performance of many creatures employing flapping wings has attracted researchers to study the aerodynamics of bionic flapping wings, which has potential application in designing micro air vehicles and autonomous underwater vehicles. Bionic movements usually have to adapt to the low Reynolds number environment. It is noteworthy that the flow field of a flapping wing at low Reynolds numbers flow state is closely related to the complex non-linear shedding and viscous phenomenon, especially in a three-dimensional (3D) flapping wing. In order to observe the influence of the viscous phenomenon on flapping wing propulsive performance at low Reynolds numbers, the flow field characteristics of the 3D flapping wing under different Reynolds numbers are discussed using the immersed boundary-lattice Boltzmann method with the Chinese supercomputer TianHe-II in this paper. The influence of kinematic parameters on the flow characteristics at low Reynolds number is particularly emphasized, considering that the biological movement involves many kinematic parameters, the unsteady flow field and vortex structure around the flapping wing are analyzed in detail. This study reports that the law of the flapping wing propulsive performance strongly depends on kinematic parameters that affect the vortex changes. The underlying flow mechanism behind flapping wing performance at low Reynolds numbers has been explored, which will make it possible to apply superior kinematic parameters to improve the propulsive performance of a flapping-like new airplane.
Note: Optical fiber two-way time transfer based on single photon counting approach
Authors: Trojanek Pavel , Prochazka Ivan
Published: August 2018

We are reporting on time transfer parameters of a newly presented method of the Two-Way Time Transfer (TWTT) using the single photon counting approach. The method utilizes two Single Photon Avalanche Diode (SPAD) detectors located on both ends of the optical channel. Each of the SPAD detectors measures the common signal taken from both communication directions on its location. The mixed signal is then mathematically decomposed back to the original, separated signals, whose time shifts are then measured, and the absolute time shift of the two distant time scales is calculated. The photon counting approach was utilized due to its great beneficence for the TWTT as most of the systematic errors can be eliminated, and, additionally, an optical power of only about −100 dBm is necessary for the measurement. It makes the method usable in optical fiber channels with the lengths of more than 500 km without any amplification. The presented TWTT method can be performed for any communication wavelength when proper SPAD detectors are used. In our free-air experiment, we utilized two commonly used multimode small form factor pluggable laser modules and the SPAD detector developed by our group. The long-term timing stability of the SPAD detectors and the timing system used is better than 100 fs. The ultimate precision of the time transfer of less than 1 ps for averaging times of hours was achieved, and the reliability of the new TWTT method was proven.
Interband absorption in PbTe/PbSnTe-based type-II superlattices
Authors: Ishida Akihiro , Naruse Kazuma , Nakashima Seisuke , Takano Yasushi , Du Shaoqing , Hirakawa Kazuhiko
Published: August 2018

Short-period PbTe/Pb1−xSnxTe/CaTe (x = 0.36, 0.48) superlattices were prepared on a KCl (100) substrate and their interband optical absorption was measured. The superlattice indicated strong absorption of more than 2500 cm−1, corresponding to the electron transition from the first valence subband in the PbSnTe layer to the conduction subband in the PbTe layer, which can give enough optical gain for laser operation under inversion population. The absorption coefficient increased with lowering of temperature in the wavelength region from 7 to more than 20 μm. The enhancement of the absorption coefficient was explained by the enhancement of the overlap of wave functions and the two-dimensional density of states in the type-II superlattice retaining a large value even with reduced band gap. The conduction-band offset of the PbTe/Pb0.64Sn0.36Te type-II heterojunction was estimated to be 120 meV.
Energy of the quasi-free electron in CO and HD: Probing intermolecular potentials within the local Wigner-Seitz model
Authors: Evans C. M. , Flor Baxter , Krynski Kamil , Streeter Zachary , Findley G. L.
Published: August 2018

We present the quasi-free electron energy V0(ρ) in the weakly polar fluids CO and HD from gas to liquid densities ρ, on noncritical isotherms, and at a temperature near the critical isotherm. These results represent the first systematic investigation of V0(ρ) in polar fluids across a broad density range and illustrate that field enhanced photoemission can be used to obtain data in such systems. We show that the local Wigner-Seitz model for V0(ρ), when coupled with thermodynamic data for the fluids, can yield optimized intermolecular potential parameters, as well as the magnitude of the zero kinetic energy electron scattering length.
An ultra-thin coplanar waveguide filter based on the spoof surface plasmon polaritons
Authors: Wang Jun , Zhao Lei , Hao Zhang-Cheng , Cui Tie Jun
Published: August 2018

In this letter, a coplanar waveguide (CPW) filter based on spoof surface plasmon polaritons (SSPPs) in the microwave frequency band is proposed, which can achieve multi-band transmission by using periodic holes etched on the middle line of a CPW. Compared to the conventional SSPP designs, the proposed SSPP-based waveguide filter removes the gradual structure for the mode conversion. Simultaneously, the transmission efficiency of high-order modes is obviously improved by employing periodic holes etched on both the side grounds of the CPW. The physical mechanism of the proposed SSPP-based waveguide filter is explained with the aid of the dispersion curves and electric field distributions. Experimental results validate the proposed concept, and the measured results are in good agreement with the simulated ones, which indicates that the proposed SSPP-based waveguide filter can find potential applications in plasmonic integrated circuits at microwave frequencies.
Destabilization of pseudo-Jahn–Teller distortion in cesium-doped hexagonal tungsten bronzes
Authors: Yoshio Satoshi , Okada Mika , Adachi Kenji
Published: August 2018

In Cs-doped hexagonal tungsten bronzes (Cs-HTBs), X-ray diffraction–Rietveld analysis has revealed that an increase in the alkali dopant and oxygen vacancies (VO) elongate the c-axis, contract the a-axis, and decrease the deviations of the W–O distance and W coordinates from those of a regular WO6 octahedron. These structural changes are interpreted as a destabilization of pseudo-Jahn–Teller (PJT) distortion by electron donation from Cs+ and VO. A dramatic difference is observed in the destabilization efficiency between the donated electrons from Cs+ and VO, suggesting that the former and latter electrons should be delocalized and localized, respectively. First-principles density functional theory calculations using optB86b-vdW functionals reproduced the behavior of c-axis elongation and a-axis contraction by Cs doping. The projected orbital density of states indicates that the Cs-derived electrons are donated to W-5dyz and W-5dzx orbitals to extend along the c-axis, whereas the VO-derived electrons are donated to W-5dxy and W-5dx2−y2 orbitals to strongly localize in the a–b plane. In HTBs, an anisotropic increase and decrease in the t2g* antibonding electrons from the doped alkali are concluded to induce the anisotropic structural change in PJT distortions.
Surface action spectroscopy with rare gas messenger atoms
Authors: Wu Zongfang , Płucienik Agata , Liu Yun , Naschitzki Matthias , Wachsmann Walter , Gewinner Sandy , Schöllkopf Wieland , Kuhlenbeck Helmut , Freund Hans-Joachim
Published: August 2018

Action spectroscopy with inert gas messengers is commonly used for the characterization of aggregates in the gas phase. The messengers, often rare gas atoms or D2 molecules, are attached to the gas phase aggregates at low temperature. Vibrational spectra of the aggregates are measured via detection of inert gas desorption following a vibrational excitation by variable-energy infrared light. We have constructed an apparatus for the application of action spectroscopy to surfaces of solids with the aim of establishing a new method for the vibrational spectroscopy of surfaces and deposited clusters. Experiments performed for neon covered V2O3(0001) show that this method can provide information about surface vibrations. Besides the surface sensitive channel, there is also a bulk sensitive one as demonstrated with the example of CeO2(111) thin film data. Unlike infrared reflection absorption spectroscopy, normalization to a reference spectrum is not required for action spectroscopy data, and unlike high resolution electron energy loss spectroscopy, the action spectroscopy method does not suffer from moderate resolution nor from multiple excitations. Selective decoration of specific surface features with messenger atoms may be utilized to focus the spectroscopic information onto these features.
Extended operating temperature window of giant negative thermal expansion in Sn-doped Ca2RuO4
Authors: Takenaka K. , Inoue N. , Mizuno Y. , Okamoto Y. , Katayama N. , Sakai Y. , Nishikubo T. , Azuma M.
Published: August 2018

Colossal negative thermal expansion (NTE) recently discovered in layered ruthenate Ca2RuO4 is achieved by microstructural effects because of the crystal grains showing highly anisotropic thermal distortion and the pores in the sintered body. To improve the NTE properties, we have investigated element-substitution effects. We discovered that Sn doping expanded the operating-temperature window toward higher temperatures up to 700 K and improved the temperature linearity of NTE without decreasing the total volume change related to NTE. We discuss changes in NTE properties caused by Sn doping in terms of the electronic states and the structural transformation.
Displacement current during the formation of positive streamers in atmospheric pressure air with a highly inhomogeneous electric field
Authors: Beloplotov Dmitry V. , Lomaev Mikhail I. , Sorokin Dmitry A. , Tarasenko Victor F.
Published: August 2018

This paper presents experimental data on the dynamics of positive streamers formation in a highly inhomogeneous electric field under threshold for the breakdown of the gap conditions as well as at high voltage. The glow of the streamer was registered with a four-channel intensified charge-coupled device camera with simultaneous recording of voltage and current characteristics per pulse. It was shown that the streamer appearance is accompanied by a displacement current pulse induced by a redistribution of the electric field strength in the gap. We call this current the dynamic displacement current (DDC). The DDC value changes during the streamer propagation in the gap. It reaches the maximum values when the streamer starts and when it is close to bridge the gap. The DDC was also registered with a collector placed behind the grid plane electrode which is usually applied for the registration of runaway electrons when a negative streamer is formed. It was shown that the DDC allows to study the features of the streamer formation.
New Products
Authors: Mandelis Andreas
Published: August 2018

In order to supplement manufacturers’ information, this Department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications.
A narrative review and synthesis to inform health workforce preparation for the Health Care Homes model in primary healthcare in Australia
Authors: McKittrick Rachel , McKenzie Rosemary
Published: August 2018

The Australian Government Health Care Homes (HCH) model recently implemented in general practice targets people with chronic complex conditions. Identifying how general practitioners (GPs) and practice nurses (PNs) can work within this model is important given existing health workforce challenges. A narrative review and synthesis has been undertaken to develop a preliminary understanding of this, incorporating literature describing health workforce challenges, GP and PN functions, and team-based care; supplemented by interviews with key informants from within the primary healthcare system. Narrative synthesis principles guided literature analysis. Interview data were thematically analysed. A clear rationale for health workforce reform was ascertained and functions for the GP and PN under the HCH model were determined. The model was found to be an opportunity for an enhanced PN role in a team-based approach to care with the GP. Challenges to advancing the PN role and team-based care were identified, including the medical dominance of the health system and the significant culture change required by general practices to fully implement the model. Enablers included strong nursing leadership and improved ongoing education for PNs to unlock their capacity. The HCH model is an opportunity to strengthen primary healthcare, provided concerted action is taken regarding these challenges and enablers.
Amelioration by quercetin of insulin resistance and uterine GLUT4 and ERα gene expression in rats with polycystic ovary syndrome (PCOS)
Authors: Neisy Asma , Zal Fatemeh , Seghatoleslam Atefeh , Alaee Sanaz
Published: August 2018

Insulin resistance (IR) and infertility are two major complications of polycystic ovary syndrome (PCOS), which are the results of changes in certain parts of the reproductive and metabolic systems. We aimed to observe the effect of quercetin on dehydroepiandrosterone (DHEA)-induced PCOS and insulin resistance in rats. All animals were divided into five groups and DHEA was used to induce PCOS. Bodyweight and ovarian morphology of all groups were observed. Fasting blood glucose and insulin levels were analysed. The homeostasis model assessment of insulin resistance (HOMA-IR) method was used for IR level determination. The expression of oestrogen receptor α (ERα) and glucose transporter 4 (GLUT4) genes in the uterus was examined by real-time polymerase chain reaction. Liver hexokinase (HK) and glucokinase (GK) activity was determined using spectrophotometry. Quercetin significantly improved the IR state in PCOS rats. PCOS resulted in a decrease in liver GK and an increase in liver HK specific activity, whereas quercetin increased both liver HK and GK activity. Our data also showed a significant reduction in uterine ERα and GLUT4 expression in the PCOS group, which was increased by quercetin. A remarkable effect of quercetin was the intensive reduction of PCOS-IR and significant induction of uterine GLUT4 and ERα gene expression; it could thus be a possible effective treatment for PCOS and its complications, IR and infertility.
Generating carbon schwarzites via zeolite-templating
Authors: Braun Efrem , Lee Yongjin , Moosavi Seyed Mohamad , Barthel Senja , Mercado Rocio , Baburin Igor A. , Proserpio Davide M. , Smit Berend
Published: August 2018

Significance

Nanocarbons can be characterized by their curvature—that is, positively curved fullerenes, zero-curved graphene, and negatively curved schwarzites. Schwartzites are fascinating materials but have not been synthesized yet, although disordered materials with local properties similar to schwarzites (“random schwarzites”) have been isolated. A promising synthetic method allows for the interior surfaces of zeolites to be templated with

s
p

2

carbon, but theoretical study of these zeolite-templated carbons (ZTCs) has been limited because of their noncrystalline structures. In this work, we develop an improved molecular description of ZTCs, show that they are equivalent to schwartzites, and thus make the experimental discovery of schwarzites ex post facto. Our topological characterization of ZTCs lends insights into how template choice allows for the tunability of ordered microporous carbons.
Assessment of the austemperability of high-silicon cast steels through Jominy hardenability tests
Authors: Tenaglia Nicolás Emanuel , Boeri Roberto Enrique , Massone Juan Miguel , Basso Alejandro Daniel
Published: August 2018

The austemperability of seven high silicon cast steels with different alloy contents was characteri sed. The maximum round bar diameter that can be fully austempered changed from about 10 mm for an unalloyed steel to more than 70 mm for a low-alloy steel. The austemperability was calculated by applying a procedure based on a standard Jominy test and the characterisation of the microstructure along the Jominy sample. The method, which was validated experimentally, creates a relatively simple procedure to measure austemperability. Processing factors such as the ability of the salt bath to extract heat and the austempering temperature are accounted for the method. The metallographic study revealed the influence of microsegregation on hardenability, which is particularly important for cast steels.
Predation risk affects egg mass but not egg steroid hormone concentrations in yellow-legged gulls
Authors: Possenti Cristina Daniela , Bentz Alexandra Bea , Romano Andrea , Parolini Marco , Caprioli Manuela , Rubolini Diego , Navara Kristen , Saino Nicola
Published: August 2018

Predators have both direct, consumptive effects on their prey and non-lethal effects on physiology and behavior, including reproductive decisions, with cascading effects on prey ecology and evolution. Here, we experimentally tested such non-lethal effects of exposure to increased predation risk on clutch size, egg mass, and the concentration of yolk steroid hormones in the yellow-legged gull Larus michahellis. We simulated increased predation risk by displaying stuffed predators (adult fox Vulpes vulpes, and adult buzzard Buteo buteo) to breeding adults before egg laying. The concentration of corticosterone, which has been shown to increase under exposure to maternal predation risk in other species, and of testosterone did not differ between eggs from mothers exposed to the predators and eggs from control mothers (i.e., eggs exposed to a novel object of similar size and position to the stuffed predators). The concentration of the two hormones negatively covaried. Clutch size did not vary according to experimental treatment, whereas egg mass was markedly larger in clutches from nests exposed to predators than in clutches from control nests. By increasing egg mass, mothers may reduce the risk of cooling of the eggs when incubation is impeded by predators, boost energy reserves, reduce post-natal detectability caused by food solicitation, and/or enhance development at hatching, thus increasing the chances of offspring survival. In general, our results are inconsistent with most of the few previous studies on similar non-lethal predator effects and suggest that such effects may vary among species according to ecological conditions, social behavior, and developmental mode.
Impact of an artificial structure on the benthic community composition in the southern North Sea: assessed by a morphological and molecular approach
Authors: Klunder Lise , Lavaleye Marc S S , Filippidi Amalia , van Bleijswijk Judith D L , Reichart Gert-Jan , van der Veer Henk W , Duineveld Gerard C A , Mienis Furu
Published: August 2018

Man-made structures in the North Sea are known to act as artificial reefs by providing a habitat for sessile epifauna in a predominantly soft sediment environment. This epifauna is hypothesized to cast a so-called “shadow” over the soft sediment ecosystem by altering the nutrient composition in the overlying water column. In addition, the structure itself could alter currents and thereby influence the deposition and erosion of the sediments in the wake of the platform. This study aims to assess the long-term effects of a gas platform in the southern North Sea on the surrounding benthic community by both morphological and molecular identification of benthic species. The species composition and a set of abiotic factors of the sediment around a gas platform were assessed along four transects. Differences for the abiotic factors were found in the closer vicinity of the platform in the direction corresponding to the predominant currents. The number of benthic fauna families found in the molecular approach were on average three times higher than for the morphological approach. Both approaches showed that small differences occurred primarily due to changes in sedimentary organic matter content. Differences in species composition were more pronounced between transects rather than between distances from the platform.
Development and validation of the PEPPER framework (Prenatal Exposure PubMed ParsER) with applications to food additives
Authors: Boland Mary Regina , Kashyap Aditya , Xiong Jiadi , Holmes John , Lorch Scott
Published: August 2018

Background

Globally, 36% of deaths among children can be attributed to environmental factors. However, no comprehensive list of environmental exposures exists. We seek to address this gap by developing a literature-mining algorithm to catalog prenatal environmental exposures.

Methods

We designed a framework called

PEPPER

Prenatal Exposure PubMed ParsER to a) catalog prenatal exposures studied in the literature and b) identify study type. Using PubMed Central, PEPPER classifies article type (methodology, systematic review) and catalogs prenatal exposures. We coupled PEPPER with the FDA’s food additive database to form a master set of exposures.

Results

We found that of 31 764 prenatal exposure studies only 53.0% were methodology studies. PEPPER consists of 219 prenatal exposures, including a common set of 43 exposures. PEPPER captured prenatal exposures from 56.4% of methodology studies (9492/16 832 studies). Two raters independently reviewed 50 randomly selected articles and annotated presence of exposures and study methodology type. Error rates for PEPPER’s exposure assignment ranged from 0.56% to 1.30% depending on the rater. Evaluation of the study type assignment showed agreement ranging from 96% to 100% (kappa = 0.909, p < .001). Using a gold-standard set of relevant prenatal exposure studies, PEPPER achieved a recall of 94.4%.

Conclusions

Using curated exposures and food additives; PEPPER provides the first comprehensive list of 219 prenatal exposures studied in methodology papers. On average, 1.45 exposures were investigated per study. PEPPER successfully distinguished article type for all prenatal studies allowing literature gaps to be easily identified.
Corynebacterium macginleyi-associated Blebitis: A Case Report
Authors: Qin Vincent , Laurent Terry , Ledoux Aurélie
Published: August 2018

Purpose:

The purpose of this study was to report a rare case of posttrabeculectomy bleb-related infection associated with Corynebaterium macginleyi, a rare conjunctival pathogen.

Methods:

Case description including clinical imaging and microbiology data, and literature review of Corynebacterium macginleyi-related infections.

Results:

A 60-year-old glaucomatous female patient presented with a bleb-related infection 6 years after trabeculectomy in her right eye, suggestive of blebitis. No bleb-related endophthalmitis was reported.

Conclusions:

C. macginleyi is a rare conjunctival pathogen that can cause conjunctivitis and, rarely, bleb-related infections.
Micropulse Versus Continuous Wave Transscleral Cyclophotocoagulation in Refractory Pediatric Glaucoma
Authors: Abdelrahman Ahmed M. , El Sayed Yasmine M.
Published: August 2018

Purpose:

The aim of this study was to compare the safety and efficacy of micropulse cyclophotocoagulation (MP-CPC) and transscleral continuous wave cyclophotocoagulation (CW-CPC) for the treatment of refractory glaucoma in the pediatric age group.

Methods:

This prospective study included 45 eyes of 36 children requiring transscleral cyclophotocoagulation, in the period spanning from September 2016 to August 2017, using micropulse (MP-CPC) or continuous wave (CW-CPC) modes. The intraocular pressure (IOP) reduction, success rates, and complications were compared for both groups. Success was defined as an IOP of 5 to 21 mm Hg, in the absence of vision-threatening complications at 6 months.

Results:

The MP-CPC group included 17 eyes, in patients aged 67.8±48 months, and the CW-CPC group included 28 eyes, in patients aged 61.3±38.3 months. There was a tendency toward lower IOP in the MP-CPC group at all follow-ups, almost reaching statistical significance at 2 weeks and 3 months (P=0.05). IOP reduction was 63% in the MP-CPC group and 67% in the CW-CPC group (P=0.6). The success rate was higher in the MP-CPC group (71% vs. 46% in the CW-CPC group), but the difference was not significant (P=0.1). No significant complications were noted in the MP-CPC group whereas, in the CW-CPC group, 1 eye developed phthisis bulbi, and 2 eyes had severe pain and uveitis (P=0.3).

Conclusions:

Both the MP-CPC and CW-CPC are effective in lowering the IOP in children with refractory glaucoma. However, the rate of complications, pain, and inflammation seem to be lower with the micropulse mode, making it a safer alternative for cyclophotocoagulation, especially since retreatments are often needed.
CO2 Laser-assisted Deep Sclerectomy Combined With Phacoemulsification in Patients With Primary Open-angle Glaucoma and Cataract
Authors: Yu Xiaojiao , Chen Chunlin , Sun Min , Dong Denghao , Zhang Shuoji , Liu Pei , Yuan Rongdi , Ye Jian
Published: August 2018

Purpose:

To assess the safety and efficacy of CO2 laser-assisted sclerectomy surgery (CLASS) combined with phacoemulsification in patients with primary open-angle glaucoma (POAG) and visually significant cataracts.

Materials and Methods:

This was a prospective, uncontrolled, interventional case series. Seventeen patients (17 eyes) diagnosed with POAG and cataracts were enrolled starting from November 2015. All subjects underwent CLASS combined with phacoemulsification surgery by the same surgeon. After the surgery, all patients were followed for 12 months. The preoperative to postoperative changes in intraocular pressure (IOP), glaucoma medication requirements, best-corrected visual acuity and adverse events were recorded.

Results:

The results of 17 eyes of 17 patients were included in the statistical analysis. The baseline mean IOP was 23.94±8.57 mm Hg (mean±SD), and patients used 2.18±0.88 types of antiglaucoma medication. At 12 months postsurgery, the mean IOP was 14.67±2.97 mm Hg, and patients used 0.59±0.87 types of antiglaucoma medication (both P<0.001). The logarithm of the minimal angle of resolution of the best-corrected visual acuity improved from 0.77±0.42 preoperatively to 0.33±0.47 postoperatively (P<0.05). Two patients experienced intraoperative perforation accompanied by iris prolapse. One patient exhibited postoperative choroidal detachment.

Conclusions:

CLASS with phacoemulsification may become a safe and effective intervention for patients with POAG and visually significant cataracts.
Evaluating the Effect of Coenzyme Q10 Augmentation on Treatment of Bipolar Depression
Authors: Mehrpooya Maryam , Yasrebifar Fatemeh , Haghighi Mohammad , Mohammadi Younes , Jahangard Leila
Published: August 2018

Background

Bipolar disorder (BPD) is a chronic and recurrent mood disorder characterized by episodes of mania, hypomania, and major depression. Based on available evidence, mitochondrial dysfunction, oxidative stress, and inflammation have important roles in the pathophysiology of bipolar depression. More specifically, it seems that coenzyme Q10 (CoQ10), a mitochondrial modulator, as well as an antioxidant and anti-inflammatory agent, might be effective in modulating these pathophysiological pathways. Accordingly, the aim of this study was to investigate whether and to what extent, compared with placebo, adjuvant CoQ10 might improve symptoms of depression in patients with BPD.

Methods

A total of 69 patients with BPD with a current depressive episode were randomly assigned either to the adjuvant CoQ10 (200 mg/d) or to the placebo group. Standard medication consisting of mood stabilizers and antidepressants was consistent 2 months prior and during the study. Depression severity for each patient was assessed based on the Montgomery-Asberg Depression Rating Scale scores at baseline, fourth week, and eighth week of the study.

Results

Symptoms of depression decreased over time in both groups. Compared with the placebo group, adjuvant CoQ10 to a standard medication improved symptoms of depression after 8 weeks of treatment. In addition, at the end of the study, it turned out that more responders were observed in the CoQ10 group, compared with the placebo group. CoQ10 had minimal adverse effects and was well tolerated.

Conclusions

The present pattern of results suggests that among patients with BPD, compared with placebo, adjuvant CoQ10 probably because of its antioxidant and anti-inflammatory properties can improve symptoms of depression over a period of 8 weeks.
Persistent Oxidative Stress in Vestibular Schwannomas After Stereotactic Radiation Therapy
Authors: Robinett Zachary N. , Bathla Girish , Wu Angela , Clark James Jason , Sibenaller Zita A. , Wilson Thomas , Kirby Patricia , Allen Bryan G. , Hansen Marlan R.
Published: August 2018

Objective:

Stereotactic radiation therapy is increasingly used to treat vestibular schwannomas (VSs) primarily and to treat tumor remnants following microsurgery. Little data are available regarding the effects of radiation on VS cells. Tyrosine nitrosylation is a marker of oxidative stress following radiation in malignant tumors. It is not known how long irradiated tissue remains under oxidative stress, and if such modifications occur in benign neoplasms such as VSs treated with significantly lower doses of radiation. We immunostained sections from previously radiated VSs with an antibody that recognizes nitrosylated tyrosine residues to assess for ongoing oxidative stress.

Study Design:

Immunohistochemical analysis.

Methods:

Four VSs, which recurred after excision, were treated with stereotactic radiation therapy. Ultimately each tumor required salvage reresection for regrowth. Histologic sections of each tumor before and after radiation were immunolabeled with a monoclonal antibody specific to nitrotyrosine and compared. Two VSs that underwent reresection of a growing tumor remnant without previous radiation therapy served as additional controls.

Results:

Irradiated tumors enlarged in volume by 3.16 to 8.62 mL following radiation. Preradiation sections demonstrated little to no nitrotyrosine immunostaining. Three of four of irradiated VSs demonstrated increased nitrotyrosine immunostaining in the postradiation sections compared with preradiation tumor sections. Nonirradiated VSs did not label with the antinitrotyrosine antibody.

Conclusions:

VSs exhibit oxidative stress up to 7 years after radiotherapy, yet these VSs continued to enlarge. Thus, VSs that grow following radiation appear to possess mechanisms for cell survival and proliferation despite radiation-induced oxidative stress.
Outcomes Following Modified Tympanomastoidectomy With Soft-wall Reconstruction
Authors: Doerfer Karl W. , Friedland David R.
Published: August 2018

Objective:

To report outcomes following modified tympanomastoidectomy with soft-wall reconstruction (MTMSWR).

Study Design:

Retrospective cohort.

Setting:

Tertiary referral center.

Patients:

Forty-seven patients (48 ears) with aggressive cholesteatoma undergoing MTMSWR.

Interventions:

Canal wall down (CWD) tympanomastoidectomy with temporalis fascia reconstruction of the posterior external auditory canal (EAC).

Main Outcome Measures:

Cholesteatoma recidivism; hearing outcomes; degree of soft-wall retraction; time to epithelialization; otorrhea.

Results:

All ears had some form of ossicular compromise. There were 41 ears with completed surveillance of which 39% demonstrated recidivism for cholesteatoma. Of these, 68.8% had a small cholesteatoma foci averaging 3.7 mm. Air pure-tone average remained stable or improved for 60.0% and declined ≤ 20 dB for 85.7%. Excluding ears unable to undergo ossicular chain reconstruction, final air-bone gap was ≤ 30 dB for 66.7%. Retraction of the reconstructed wall was absent-to-mild in 34.7% and moderate-to-full in 52.1%. Thirteen percent had soft-wall breakdown. Average time to full epithelialization of the wall was 58.5 days.

Conclusions:

MTMSWR is an option for restoring the posterior EAC wall following CWD surgery. Recidivism is comparable to canal wall up surgery, and hearing outcomes are generally better than CWD. Other advantages include rapid epithelialization, low rates of otorrhea, and restoration of a self-cleaning EAC regardless of retraction into the mastoid cavity.
Direct Acoustic Cochlear Implants Lead to an Improved Speech Perception Gap Compared to Conventional Hearing Aid
Authors: Maier Hannes , Lenarz Thomas , Dolležal Lena-Vanessa , Busch Susan
Published: August 2018

Objectives:

The objectives of this study was to evaluate the aided speech perception in quiet of direct acoustic cochlear implant (DACI) patients and the speech perception gap in comparison with hearing aid users.

Study Design:

Retrospective comparative study.

Setting:

Tertiary referral center.

Patients:

Adults with moderate-to-severe mixed hearing loss who have been implanted with a DACI and fitted with a processor for at least 6 months.

Intervention(s):

Comparison of aided monosyllabic word scores and speech perception gap of 59 DACI-implanted ears speech perception gap with published data on 208 ears aided with a conventional hearing aid (HA) divided into four different hearing loss groups between 35 and 75 dB HL.

Main Outcome Measure(s):

Aided monosyllabic word score, predicted maximum monosyllabic word recognition score (PBmax) and speech perception gap.

Results:

In terms of aided speech perception, DACI patients with cochlear reserves between 45 and 65 dB HL have a significant advantage compared with conventional HA users. A speech perception gap of 11% points for DACI and 21% points for conventional HAs were determined and an approximation of PBmax is achieved by 52% of the DACI patients compared with only 36% of the HA users.

Conclusions:

For patients with moderate-to-severe inner ear hearing loss between 45 and 65 dB HL, better speech perception in quiet is obtained with the DACI system. Compared with conventional hearing aids, speech performance with the DACI is closer to the maximally possibly score PBmax.
Adolescent Obesity Is an Independent Risk Factor for Sensorineural Hearing Loss: Results From the National Health and Nutrition Examination Survey 2005 to 2010
Authors: Kohlberg Gavriel D. , Demmer Ryan T. , Lalwani Anil K.
Published: August 2018

Objective:

We investigated the hypothesis that childhood obesity is a risk factor for sensorineural hearing loss (SNHL) independent of other metabolic risk factors.

Study Design:

A complex, multistage, stratified geographic area design for collecting representative data from noninstitutionalized US population.

Methods:

A total of 5,638 adolescents between age 12 and 19 from the NHANES database (2005–2010) were studied. Subjects with body mass index >= 95th percentile were classified as obese. SNHL was defined as average pure-tone greater than 15 dB HL for 0.5, 1, and 2 kHz or 3, 4, 6, and 8 kHz in at least 1 ear. Multivariable logistic regression models assessed incident hearing loss odds across obese patients in comparison with normal weight individuals (5th–85th percentile). Multivariable models included age, sex, socioeconomic status, race, smoke exposure, high density lipoprotein level, triglyceride level, elevated blood pressure measurement, hemoglobin A1C level, and C-reactive protein level.

Results:

The rate of SNHL was 21.5% in obese and 13.44% in normal weight adolescents (p < 0.0001). In multivariable analyses, obesity was associated with 1.73-fold increase in the odds of SNHL (95% CI: 1.25–2.40, p value = 0.006). Potentially confounding and mediating factors had minimal effect on the odds of SNHL in obese study participants (OR range of 1.69–1.75, all p values <= 0.01).

Conclusions:

Obesity is associated with higher prevalence of SNHL in adolescents independent of other potential risk factors. Future longitudinal investigations and mechanistic studies are warranted.
High Incidence and Clinical Significance of MYC Rearrangements in Primary Cutaneous Diffuse Large B-Cell Lymphoma, Leg Type
Authors: Schrader Anne M.R. , Jansen Patty M. , Vermeer Maarten H. , Kleiverda Johanna K. , Vermaat Joost S.P. , Willemze Rein
Published: August 2018

Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT) and primary cutaneous follicle center lymphoma (PCFCL) are cutaneous B-cell lymphomas (CBCL) with different clinical characteristics and behavior. PCDLBCL-LT is the most aggressive CBCL with a relatively poor prognosis. In nodal diffuse large B-cell lymphoma (DLBCL), rearrangements of the MYC gene, especially in combination with a second hit in BCL2 and/or BCL6, and double protein expression of MYC and BCL2 (DE) are adverse prognostic factors. As the clinical significance of these factors in CBCL is largely unknown, we studied the frequency and prognostic value of MYC rearrangements and DE in a cohort of 44 patients with PCDLBCL-LT and 17 patients with PCFCL. Compared with nodal DLBCL (9% to 14%), the PCDLBCL-LT patients had a high incidence of MYC rearrangements (32%), but only 2 patients (4%) had a second hit, both with BCL6. PCDLBCL-LT patients with a MYC rearrangement showed an inferior disease-specific survival (Log-rank, P=0.036) and disease-free survival (Log-rank, P=0.028), but no significant adverse effect on overall survival (Log-rank, P=0.157) at 5 years compared with patients without a MYC rearrangement. DE, present in 65% of the PCDLBCL-LT patients, was not associated with reduced survival. In the PCFCL group, MYC rearrangements and DE were not detected. In conclusion, this study identifies a high incidence of MYC rearrangements in PCDLBCL-LT compared to nodal DLBCL and further shows that a MYC rearrangement is an inferior prognostic marker in these patients. Therefore, our data suggest that it is useful to perform MYC-FISH in all newly diagnosed PCDLBCL-LT patients.