bluuebunny/crossref_metadata_2025 huggingface dataset:
Disruptive Hearing Technologies and Mild Sensorineural Hearing Loss II: Current Research on Affordable Hearing Technologies and Direct-to-Consumer Models
Authors: Johnson Carole , Danhauer Jeffrey , Jilla Anna
Published: June 2018

Recently, President Trump signed into law the Food and Drug Administration (FDA) Reauthorization Act of 2017, which included the Over-the-Counter Hearing Aid Act designed to provide greater public accessibility to and affordability of amplification for individuals with self-identified mild and moderate hearing loss through the provision of over-the-counter (OTC) hearing aids (HAs) with a direct-to-consumer (DTC) delivery model. American Speech-Language-Hearing Association and American Academy of Audiology Position Statements on OTC HAs state that these devices should only be used for adults with mild hearing losses. DTC amplification and service delivery has been available to consumers in a variety of forms for a significant period of time. However, FDA-regulated OTC HAs will not be available as described in the new law until the FDA publishes the required guidance related to the technology, safety, and labeling of such devices. With the clear similarities in mind between present and future amplification options, a literature search was conducted to review studies assessing outcomes for low-cost and DTC HAs and service-delivery models to inform what we may expect as OTC HAs enter the market. Nine studies were identified which assessed: (1) electroacoustic capabilities of low-cost and DTC HAs, (2) use of these devices in field trials, or (3) efficacy of DTC models. None of the studies reported outcomes specifically for participants with mild hearing loss. The studies had poor external validity because none included all factors that would exist in realistic uses of OTC HAs within a DTC model. Additional research will be needed as OTC HAs become available and different delivery models are proposed.
Healthcare consumers’ sensitivity to costs: a reflection on behavioural economics from an emerging market
Authors: Vuong Quan-Hoang , Ho Tung-Manh , Nguyen Hong-Kong , Vuong Thu-Trang
Published: June 2018

Decision-making regarding healthcare expenditure hinges heavily on an individual's health status and the certainty about the future. This study uses data on propensity of general health exam (GHE) spending to show that despite the debate on the necessity of GHE, its objective is clear—to obtain more information and certainty about one’s health so as to minimise future risks. Most studies on this topic, however, focus only on factors associated with GHE uptake and overlook the shifts in behaviours and attitudes regarding different levels of cost. To fill the gap, this study analyses a dataset of 2068 subjects collected from Hanoi (Vietnam) and its vicinities using the baseline-category logit method. We evaluate the sensitivity of Vietnamese healthcare consumers against two groups of factors (demographic and socioeconomic-cognitive) regarding payment for periodic GHE, which is not covered by insurance. Our study shows that uninsured, married and employed individuals are less sensitive to cost than their counterparts because they value the information in reducing future health uncertainty. The empirical results challenge the objections to periodic health screening by highlighting its utility. The relevance of behavioural economics is further highlighted through a look at the bounded rationality of healthcare consumers and private insurance companies in using and providing the service, respectively.
Coexistence of ferroelectric phases and electric field induced structural transformation in sodium potassium bismuth titanate ceramics
Authors: Veera Gajendra Babu M. , Bagyalakshmi B. , Giridharan N. V. , Dhayanithi D. , Sundarakannan B.
Published: June 2018

Lead-free sodium potassium bismuth titanate (1−x)[Na0.5Bi0.5TiO3]-x[K0.5Bi0.5TiO3] (NKBTx) ceramics have been believed to be a rhombohedral crystal system with R3c symmetry up to x = 0.16 mole fraction, right now. For the first time, on the contrary, we have disclosed the existence of a low-symmetry (MA)-type monoclinic phase (69%) along with rhombohedral R3c (31%) in the NKBT0.10 sample from Rietveld studies on conventional and high-energy synchrotron powder diffraction data in the unpoled state. The peak splitting and reduced FWHM of {110}pc and {111}pc reflections after poling indicate the field-induced structural transformation. Rietveld analysis reveals that the monoclinic (Cc) phase is partially transformed to rhombohedral (R3c) at 50 kV/cm. Two distinct dielectric anomalies are noticed in the dielectric curve at 120 and 310 °C corresponding to freezing temperature (Tf) and glass-like transition temperature (Tm), respectively. The dielectric diffusivity (γ) estimated from the modified Curie-Weiss law reveals that the sample has a relaxor behavior. Structural inhomogeneity in the nanoscale region due to cation disorder in the A-site causes relaxing nature. A well-saturated square-like ferroelectric hysteresis loop is obtained with a remnant polarization and a coercive field of 35.8 μC/cm2 and 47 kV/cm, respectively. A piezoelectric constant (d33) of 85 pC/N is obtained for the sample which is somewhat higher than that of pure Na0.5Bi0.5TiO3 ceramics.
A detailed study on the structures of steady-state collisionless kinetic sheath near a dielectric wall with secondary electron emission. I. Classic sheath and its structure transition
Authors: Qing Shaowei , Wu Chengyu
Published: June 2018

It is well known that plasma sheath presents a classic sheath structure when the dielectric-wall total electron emission coefficient Γ ≤ Γc (<1). However, the structural transition of a classic sheath near a dielectric wall when Γ→Γc is controversial about transiting to a space-charge limited (SCL) sheath or inverse sheath. In this study, the classic sheath between a Maxwellian low-temperature plasma source and a dielectric surface that emits secondary electrons is carefully investigated using a 1D3V, steady-state, kinetic sheath model within a broad range of plasma electron temperatures Te. Using the Monte Carlo method to simulate secondary electron emission (SEE) events that are based on the self-consistent primary electron velocity distribution function at the wall and a detailed SEE model, it is found that the total emitted electron velocity distribution function (EEVDF) perpendicular to the dielectric wall approximately satisfies a three-temperature Maxwellian distribution. Due to the relatively high average energy of this total EEVDF, for cases of Te with cold plasma ion assumption: (1) the critical SCL sheath does not exist; (2) Γc reaches unit; (3) the sheath disappears when Te = Tec (i.e., Γ = 1); and (4) as Te increases, the classic sheath will transit to an inverse sheath structure. Further comparative calculations predict that the magnitude of emitted electrons' average energy may lead to different experimental results between thermionic emitting surfaces which have a “cold” half-Maxwellian EEVDF and SEE surfaces. However, when the finite plasma ion temperature is considered, at the transition point, the cold plasma ion assumption is expected to be invalid, and thus a fully kinetic sheath model should be built to reveal the potential new transition regime.
Tuning flexural elastic wave propagation in electroactive phononic crystals
Authors: Zhou Xiaoling , Xu Yanlong , Wang Longqi
Published: June 2018

In this paper, we investigate the flexural elastic wave propagation properties in phononic crystals (PCs) consisting of co-axial steel and electrorheological (ER) elastomer pillars deposited on a thin plate. The finite element method and the super cell technique are used to calculate the band structures and transmission spectra. It is found that the band gap boundaries of the PCs can be tuned by applying an electric field to the ER elastomer component. The relationship between the band gap boundaries and the electric field is given. It is also found that point and line defects can be created by properly applying an electric field to some of the cells. These defects bring defect bands inside the original band gaps and lead to elastic wave confinement in the point defect or along the line defect. The dependence of the defect band frequencies on the electric field is expounded. Band gap tunability, wave confinement, and wave guiding achieved by applying electric field in this paper are useful in applications of flexural vibration reduction and energy harvesting in engineering.
Saturable absorption by carbon nanotubes on silica microtoroids
Authors: Kumagai Tsutaru , Hirota Naoya , Sato Katsuya , Namiki Koki , Maki Hideyuki , Tanabe Takasumi
Published: June 2018

Saturable absorption is a key technology for shaping the waveform of light such as in passive mode-locking. The combination of high-Q optical microcavities with a saturable absorber allows stable lasing and soliton formation. This work describes saturable absorption by carbon nanotubes (CNTs) on silica microtoroids. CNTs, which are saturable absorbers capable of a fast response time and broadband absorption, were grown on silica microtoroids by chemical vapor deposition (CVD). Raman spectroscopy revealed that the CNTs are in good quality (G/D ratio ∼ 7) and about 1.0 nm in diameter, thus confirming that a sample for use in the telecommunication band can be prepared by CVD. A counter-propagating pump-probe experiment enabled us to investigate the characteristics of CNTs as saturable absorbers while suppressing thermo-optic bistability in a microcavity system. The results revealed a saturable absorption coefficient of 0.042 cm−1, a saturable intensity of 25.9 MW/cm2, and a modulation depth of 28%. This is the first step toward the demonstration of the robust mode-locking in a silica microtoroid consisting of CNTs.
Tutorial: Common path self-referencing digital holographic microscopy
Authors: Anand A. , Chhaniwal V. , Javidi B.
Published: June 2018

Quantitative phase imaging of cells provides important morphological information about them, leading to their characterization, comparison, and identification. The interference principle when applied to microscopy provides high-contrast quantitative phase images of otherwise transparent objects along with their thickness information. The two-beam off-axis geometry of interference microscopes, in which the light beam interacting with the object interferes with a separate reference beam, is preferred since it leads to single shot quantitative phase imaging methodologies. But these techniques lead to bulky setups, with lower temporal stability not suitable for the measurement of nanometer-level cell thickness fluctuations. Self-referencing interference microscopes manipulate a portion of the light beam interacting with the cells to act as the reference, leading to compact, temporally stable geometries ideal for the measurement of cell dynamics. Here we present an overview of our efforts in the development of self-referencing digital holographic microscopes and their use in quantitative phase imaging of cells.
Space-charge and thermal effects in relativistic crossed-field devices
Authors: Marini Samuel , Rizzato Felipe B. , Pakter Renato
Published: June 2018

In this paper, a fully kinetic theory for the relativistic electron flow in a crossed-field device is developed and analyzed. The theory takes into account self-electric, self-magnetic, and thermal effects and allows determining the final stationary state achieved by the electrons in phase-space. A number of different possible stationary modes are identified and described in detail. Particular attention is given to the study of how space charge and thermal effects affect the magnetic insulation when the external magnetic field exceeds the Hull cutoff field. In the nonrelativistic limit, it is found that there is only a single mode transition that leads to the loss of the magnetic insulation. This transition is completely independent of the electron density and occurs for relatively large injection temperatures. On the other hand, in a moderate relativistic regime a much richer scenario is found with the onset of a series of stationary state mode transitions as both electron density and injection temperature are varied. In particular, it is found that the transitions and the consequent loss of magnetic insulation may occur even at very low injection temperatures. Self-consistent numerical simulation results are also presented and used to verify the theoretical findings.
A microscopic model of the Stokes–Einstein relation in arbitrary dimension
Authors: Charbonneau Benoit , Charbonneau Patrick , Szamel Grzegorz
Published: June 2018

The Stokes–Einstein relation (SER) is one of the most robust and widely employed results from the theory of liquids. Yet sizable deviations can be observed for self-solvation, which cannot be explained by the standard hydrodynamic derivation. Here, we revisit the work of Masters and Madden [J. Chem. Phys. 74, 2450–2459 (1981)], who first solved a statistical mechanics model of the SER using the projection operator formalism. By generalizing their analysis to all spatial dimensions and to partially structured solvents, we identify a potential microscopic origin of some of these deviations. We also reproduce the SER-like result from the exact dynamics of infinite-dimensional fluids.
Symmetric autobalanced Ramsey interrogation for high-performance coherent-population-trapping vapor-cell atomic clock
Authors: Abdel Hafiz M. , Coget G. , Petersen M. , Calosso C. E. , Guérandel S. , de Clercq E. , Boudot R.
Published: June 2018

We report a high-performance pulsed coherent population trapping (CPT) Cs cell atomic clock using the implementation of a symmetric auto-balanced Ramsey (SABR) interrogation sequence. The latter method is found to reduce the light-power induced frequency shift by an order of magnitude compared to a previous experiment using a simple auto-balanced Ramsey interrogation. The contribution of this shift to the clock frequency stability is now rejected in the 10−16 range at 104 s averaging time. Additional tricks, including a compensation method to reduce the laser amplitude noise contribution and the generation of novel error signals for local oscillator frequency and phase correction, have been implemented using a FPGA-based digital electronics board in order to improve the clock short-term stability by a of factor 2. The Allan deviation of the SABR-CPT clock, extracted from a selected 3 × 104 s-long dataset, is 2 × 10−13 τ−1∕2 and averages down to the level of 2.5 × 10−15 at 104 s. These results are encouraging to stimulate the development of hot cell CPT-based clocks for industrial, scientific, and instrumentation applications.
Characterisation of a sub-20 ps temporal resolution pulse dilation photomultiplier tube
Authors: Gales S. G. , Horsfield C. J. , Meadowcroft A. L. , Leatherland A. E. , Herrmann H. W. , Hares J. D. , Dymoke-Bradshaw A. K. L. , Milnes J. S. , Kim Y. H. , Kleinrath H. G. , Meaney K. , Zylstra A. B. , Parker S. , Hussey D. , Wilson L. , James S. F. , Kilkenny J. D. , Hilsabeck T. J.
Published: June 2018

A pulse-dilation photomultiplier tube (PD-PMT) with sub-20 ps temporal resolution has been developed for use with γ-ray-sensitive gas Cherenkov detectors at the National Ignition Facility to improve the diagnosis of nuclear fusion burn history and the areal density of the remaining capsule ablator. The pulse-dilation mechanism entails the application of a time-dependent, ramp waveform to a photocathode-mesh structure, introducing a time-dependent photoelectron accelerating potential. The electric field imparts axial velocity dispersion to outgoing photoelectrons. The photoelectron pulse is dilated as it transits a drift region prior to amplification in a microchannel plate and read out with a digital oscilloscope. We report the first measurements with the prototype PD-PMT demonstrating nominal <20 ps FWHM across a 400 ps measurement window and <30 ps FWHM for an extracted charge up to 300 pC. The output peak areas are linear to within 20% over 3 orders of magnitude of input intensity. 3D particle in cell simulations, which included space charge effects, have been carried out to investigate the device temporal magnification, resolution, and linearity.
Insights into the dehydrogenation of 2-thiouracil induced by slow electrons: Comparison of 2-thiouracil and 1-methyl-2-thiouracil
Authors: Kopyra Janina , Kopyra Konstancja K. , Abdoul-Carime Hassan , Branowska Danuta
Published: June 2018

In the present contribution, we study dissociative electron attachment to 1-methyl-2-thiouracil that has been synthesized and purified prior to the measurements. We compare the results with those previously obtained from 2-thiouracil. The comparison of the yield of the dehydrogenated parent anion from both the compounds allows us to assign the site from which the H atom is expulsed and to predict the mechanism that is involved in the formation of the peaks within the ion yield curve. It appears that the dehydrogenation observed for 2-thiouracil arising from the vibrational Feshbach resonances (at 0.7 and 1.0 eV) and a π*/σ* transition (at 0.1 eV) involves the bond cleavage at the N1 site, while that at the N3 site operates via the π*/σ* transition and occurs in the energy range of 1.1–3.3 eV. Besides the loss of the H atom from 1-methyl-2-thiouracil, we observe a relatively strong signal due to the loss of an entire methyl group (not observed from methyl-substituted thymine and uracil) that is formed from the N1–CH3 bond cleavage and can mimic the N-glycosidic bond cleavage within the DNA macromolecule.
Waste heat recovery in an oscillating heat pipe using interfacial electrical double layers
Authors: Shen Qingchen , Chang Chao , Tao Peng , Ning Ziyang , Rong Shujian , Liu Yanming , Song Chengyi , Wu Jianbo , Shang Wen , Deng Tao
Published: June 2018

This work presents the recovery of thermal energy through the oscillation of liquid plugs induced by phase transition within the oscillating heat pipe (OHP) during the quick heat-transfer process of the OHP. Using the electrical double layer at the liquid-solid interface in the OHP, this study demonstrated that the waste heat can be recycled and converted into useful electric energy. This recycling system generated more than 1 V of output voltage and more than 1.6 μW of peak power. The electric output generated from such a process can be used to power up small electronic devices, such as capacitors and light-emitting diodes (LEDs). The findings in this work provide an alternative approach to harvest waste heat in many devices or systems that involve the generation and removal of waste heat.
Lead-free perovskite ceramics with ultraviolet-tunable optical and magnetic properties at room temperature
Authors: Shannigrahi Santiranjan , Khoo Khoong Hong , Laskowski Robert , Tan Chee Kiang Ivan , Sharma Mohit , Lim Suo Hon , Liew Siao Li
Published: June 2018

Potassium sodium niobate (KNN) is a lead free ceramic that can potentially replace PZT (Pb(ZrTi)O3). However, KNN suffers from a few major disadvantages. These include the presence of highly volatile alkaline elements and stoichiometry sensitive properties coupled with severe difficulties in controlling the composition. In this work, La doped sodium potassium niobate based perovskite (ABO3) ceramics, more specifically [{(1-x)(K0.5Na0.5)xLa}Nb(1–2x/5)O3] (0 < x < 0.1), have been developed. Among these, the material at 5 mol. % La doping appears with an unusually high density up to 99% of its theoretical value, while densities of the parent K0.5N0.5NbO3 (KNN) ceramics typically only reach ∼70% to 89% of the theoretical limit. The developed ceramics in their circular and rectangular disk form with thickness 0.8 mm show transparency and most importantly, this transparency is electrically tunable up to 52%. Additionally, the material shows sensitivity of its magnetic and optical properties to ultraviolet (UV) irradiation, i.e., these materials transform to a metastable and reversible state that exhibits graded color change from clear to deep blue and shows a considerable increase in magnetization under UV exposure. This feature makes the developed ceramics attractive for the fabrication of new generation devices; e.g., powerless UV detectors as well as protectors, since it absorbs UV completely. Based on first-principles calculations, we developed a model that attributes these observations to the occupancy of La fxyz orbitals induced by UV excitations. The model also indicates that UV induced absorption in the visible range and magnetism are related.
Nucleation and propagation of thermomagnetic avalanches in thin-film superconductors (Review Article)
Authors: Vestgården J. I. , Johansen T. H. , Galperin Y. M.
Published: June 2018

Stability of the vortex matter—magnetic flux lines penetrating into the material—in type-II superconductor films is crucially important for their application. If some vortices get detached from pinning centres, the energy dissipated by their motion will facilitate further depinning, and may trigger an electromagnetic breakdown. In this paper, we review recent theoretical and experimental results on development of the above mentioned thermomagnetic instability. Starting from linear stability analysis for the initial critical-state flux distribution we then discuss a numerical procedure allowing to analyze developed flux avalanches. As an example of this approach we consider ultra-fast dendritic flux avalanches in thin superconducting disks. At the initial stage the flux front corresponding to the dendrite's trunk moves with velocity up to 100 km/s. At later stage the almost constant velocity leads to a specific propagation regime similar to ray optics. We discuss this regime observed in superconducting films coated by normal strips. Finally, we discuss dramatic enhancement of the anisotropy of the flux patterns due to specific dynamics. In this way we demonstrate that the combination of the linear stability analysis with the numerical approach provides an efficient framework for understanding the ultra-fast coupled nonlocal dynamics of electromagnetic fields and dissipation in superconductor films.
Theory of type-II superconductivity in ferromagnetic metals with triplet pairing
Authors: Mineev V. P.
Published: June 2018

The superconducting state in uranium compounds UGe2, URhGe and UCoGe is formed at temperatures far below the Curie temperature pointing on nonconventional nature of superconductivity in these materials—namely the superconductivity with triplet pairing. The emergence of superconductivity is accompanied by the slight magnetization expulsion typical for the type-II superconductors. Following classic Abrikosov paper I develop the theory of type-II superconductivity in application to two-band ferromagnetic metal with equal spin triplet pairing.
Full-dimensional quantum dynamics calculations for H + CHD3 → H2 + CD3: The effect of multiple vibrational excitations
Authors: Ellerbrock Roman , Manthe Uwe
Published: June 2018

Initial state-selected reaction probabilities for the H + CHD3 → H2 + CD3 reaction starting from various different ro-vibrational states of CHD3 are studied by accurate full-dimensional (12D) quantum dynamics calculation for vanishing total angular momentum (J = 0). The calculations employ the quantum transition state concept and the multi-layer multi-configurational time-dependent Hartree approach. First results focusing on fundamental excitations and the reactivity borrowing effect were communicated recently [R. Ellerbrock and U. Manthe, J. Chem. Phys. 147, 241104 (2017)]. In the present work, all vibrational states of the methane reactant are considered. It is found that energy deposited in overtones and combination bands is less efficient in promoting reactivity than expected from separable or sudden models. Furthermore, the effects of rotational excitation on the reactivity are studied in detail.
Power factor enhancement in a composite based on the half-Heusler antimonide TmNiSb
Authors: Synoradzki Karol , Ciesielski Kamil , Kępiński Leszek , Kaczorowski Dariusz
Published: June 2018

Electrical transport studies of half-Heusler (HH)-based composites (TmNiSb)1−x(TmNiSn)x were carried out in a wide temperature range aimed at searching for possible enhancement in the thermoelectric power factor (PF) over that observed in the parent compound TmNiSb. The best thermoelectric performance was found in the sample with x = 0.25, which showed PF = 1.3 × 10−3 W/mK at 1000 K, i.e., about 70% larger than PF of TmNiSb at the same temperature. The PF improvement was obtained due to the formation in the composite system of a microstructure in which semiconducting-like particles of TmNiSb were covered with a metallic layer of TmNiSn. The largest Seebeck coefficient S = 137 μV/K was observed for HH alloy TmNiSb at 560 K. In turn, TmNiSn showed a metallic behavior with small negative thermoelectric power (S = –2.6 μV/K).
How many reptiles are killed by cats in Australia?
Authors: Woinarski J. C. Z. , Murphy B. P. , Palmer R. , Legge S. M. , Dickman C. R. , Doherty T. S. , Edwards G. , Nankivell A. , Read J. L. , Stokeld D.
Published: June 2018

Context Feral cats (Felis catus) are a threat to biodiversity globally, but their impacts upon continental reptile faunas have been poorly resolved. Aims To estimate the number of reptiles killed annually in Australia by cats and to list Australian reptile species known to be killed by cats. Methods We used (1) data from >80 Australian studies of cat diet (collectively >10 000 samples), and (2) estimates of the feral cat population size, to model and map the number of reptiles killed by feral cats. Key results Feral cats in Australia’s natural environments kill 466 million reptiles yr–1 (95% CI; 271–1006 million). The tally varies substantially among years, depending on changes in the cat population driven by rainfall in inland Australia. The number of reptiles killed by cats is highest in arid regions. On average, feral cats kill 61 reptiles km–2 year–1, and an individual feral cat kills 225 reptiles year–1. The take of reptiles per cat is higher than reported for other continents. Reptiles occur at a higher incidence in cat diet than in the diet of Australia’s other main introduced predator, the European red fox (Vulpes vulpes). Based on a smaller sample size, we estimate 130 million reptiles year–1 are killed by feral cats in highly modified landscapes, and 53 million reptiles year–1 by pet cats, summing to 649 million reptiles year–1 killed by all cats. Predation by cats is reported for 258 Australian reptile species (about one-quarter of described species), including 11 threatened species. Conclusions Cat predation exerts a considerable ongoing toll on Australian reptiles. However, it remains challenging to interpret the impact of this predation in terms of population viability or conservation concern for Australian reptiles, because population size is unknown for most Australian reptile species, mortality rates due to cats will vary across reptile species and because there is likely to be marked variation among reptile species in their capability to sustain any particular predation rate. Implications This study provides a well grounded estimate of the numbers of reptiles killed by cats, but intensive studies of individual reptile species are required to contextualise the conservation consequences of such predation.
Squeezing and stick–slip friction behaviors of lubricants in boundary lubrication
Authors: Xu Rong-Guang , Leng Yongsheng
Published: June 2018

Significance

Lubricant films under extreme confinement at nanometer scales play a crucial role in lubrication engineering. Improved understanding of squeezing and friction behaviors of such ultrathin films can lead to strategies for preventing surface failure and efficient national energy usage. Through computer simulations we show that lubricant films under compression can solidify below some critical monolayers distance. Under sliding friction these solidified films exhibit stick–slip friction in which the slip occurs at solid–lubricant interfaces. However, dilation of the lubricant during slips (a signature of shear melting) is never observed, which is consistent with other experimental findings. These insights, with strong support from surface force balance experiments, may open the way to improved lubricant design.
Healing tourists with religion: Saint Rita's cult in Poland.
Authors: Kuźma I. B.
Published: June 2018

This chapter examines the emergence of the cult of St Rita of Cascia in Poland, in Krakow in particular, where the post-communist era has seen the development, especially in Catholic areas, of new processional routes associated with transnational cults. An examination of the Polish petitions of the faithful directed to St Rita has shown that most requests concern physical and mental health.
Saint Rita of Cascia: an evolving devotion in Dublin's inner city.
Authors: Kiely T.
Published: June 2018

This chapter explores the evolution and anatomy of the devotional practice among a predominantly female congregation, who attend a weekly novena mass in Dublin, Ireland, to seek favours and support from a saint (St Rita of Cascia) who is simultaneously a figure from medieval Italy and an ordinary woman like them, who understands their ongoing practical worries.
NOD is a plus end–directed motor that binds EB1 via a new microtubule tip localization sequence
Authors: Ye Anna A. , Verma Vikash , Maresca Thomas J.
Published: June 2018

Chromosome congression, the process of positioning chromosomes in the midspindle, promotes the stable transmission of the genome to daughter cells during cell division. Congression is typically facilitated by DNA-associated, microtubule (MT) plus end–directed motors called chromokinesins. The Drosophila melanogaster chromokinesin NOD contributes to congression, but the means by which it does so are unknown in large part because NOD has been classified as a nonmotile, orphan kinesin. It has been postulated that NOD promotes congression, not by conventional plus end–directed motility, but by harnessing polymerization forces by end-tracking on growing MT plus ends via a mechanism that is also uncertain. Here, for the first time, it is demonstrated that NOD possesses MT plus end–directed motility. Furthermore, NOD directly binds EB1 through unconventional EB1-interaction motifs that are similar to a newly characterized MT tip localization sequence. We propose NOD produces congression forces by MT plus end–directed motility and tip-tracking on polymerizing MT plus ends via association with EB1.
Microtubules assemble near most kinetochores during early prometaphase in human cells
Authors: Sikirzhytski Vitali , Renda Fioranna , Tikhonenko Irina , Magidson Valentin , McEwen Bruce F. , Khodjakov Alexey
Published: June 2018

For proper segregation during cell division, each chromosome must connect to the poles of the spindle via microtubule bundles termed kinetochore fibers (K-fibers). K-fibers form by two distinct mechanisms: (1) capture of astral microtubules nucleated at the centrosome by the chromosomes’ kinetochores or (2) attachment of kinetochores to noncentrosomal microtubules with subsequent transport of the minus ends of these microtubules toward the spindle poles. The relative contributions of these alternative mechanisms to normal spindle assembly remain unknown. In this study, we report that most kinetochores in human cells develop K-fibers via the second mechanism. Correlative light electron microscopy demonstrates that from the onset of spindle assembly, short randomly oriented noncentrosomal microtubules appear in the immediate vicinity of the kinetochores. Initially, these microtubules interact with the kinetochores laterally, but end-on attachments form rapidly in the first 3 min of prometaphase. Conversion from lateral to end-on interactions is impeded upon inhibition of the plus end–directed kinetochore-associated kinesin CenpE.
Tracking the sarcoplasmic reticulum membrane voltage in muscle with a FRET biosensor
Authors: Sanchez Colline , Berthier Christine , Allard Bruno , Perrot Jimmy , Bouvard Clément , Tsutsui Hidekazu , Okamura Yasushi , Jacquemond Vincent
Published: June 2018

Ion channel activity in the plasma membrane of living cells generates voltage changes that are critical for numerous biological functions. The membrane of the endoplasmic/sarcoplasmic reticulum (ER/SR) is also endowed with ion channels, but whether changes in its voltage occur during cellular activity has remained ambiguous. This issue is critical for cell functions that depend on a Ca2+ flux across the reticulum membrane. This is the case for contraction of striated muscle, which is triggered by opening of ryanodine receptor Ca2+ release channels in the SR membrane in response to depolarization of the transverse invaginations of the plasma membrane (the t-tubules). Here, we use targeted expression of voltage-sensitive fluorescence resonance energy transfer (FRET) probes of the Mermaid family in differentiated muscle fibers to determine whether changes in SR membrane voltage occur during depolarization–contraction coupling. In the absence of an SR targeting sequence, FRET signals from probes present in the t-tubule membrane allow calibration of the voltage sensitivity and amplitude of the response to voltage-clamp pulses. Successful SR targeting of the probes was achieved using an N-terminal domain of triadin, which completely eliminates voltage-clamp–activated FRET signals from the t-tubule membrane of transfected fibers. In fibers expressing SR-targeted Mermaid probes, activation of SR Ca2+ release in the presence of intracellular ethyleneglycol-bis(β-amino-ethyl ether)-N,N,N′,N′-tetra acetic acid (EGTA) results in an accompanying FRET signal. We find that this signal results from pH sensitivity of the probe, which detects cytosolic acidification because of the release of protons upon Ca2+ binding to EGTA. When EGTA is substituted with either 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid or the contraction blocker N-benzyl-p-toluene sulfonamide, we find no indication of a substantial change in the FRET response caused by a voltage change. These results suggest that the ryanodine receptor–mediated SR Ca2+ efflux is well balanced by concomitant counterion currents across the SR membrane.
Deep convolutional networks for quality assessment of protein folds
Authors: Derevyanko Georgy , Grudinin Sergei , Bengio Yoshua , Lamoureux Guillaume
Published: June 2018

Motivation

The computational prediction of a protein structure from its sequence generally relies on a method to assess the quality of protein models. Most assessment methods rank candidate models using heavily engineered structural features, defined as complex functions of the atomic coordinates. However, very few methods have attempted to learn these features directly from the data.

Results

We show that deep convolutional networks can be used to predict the ranking of model structures solely on the basis of their raw three-dimensional atomic densities, without any feature tuning. We develop a deep neural network that performs on par with state-of-the-art algorithms from the literature. The network is trained on decoys from the CASP7 to CASP10 datasets and its performance is tested on the CASP11 dataset. Additional testing on decoys from the CASP12, CAMEO and 3DRobot datasets confirms that the network performs consistently well across a variety of protein structures. While the network learns to assess structural decoys globally and does not rely on any predefined features, it can be analyzed to show that it implicitly identifies regions that deviate from the native structure.

Availability and implementation

The code and the datasets are available at https://github.com/lamoureux-lab/3DCNN_MQA.

Supplementary information

Supplementary data are available at Bioinformatics online.
PTPN11 Gain-of-Function Mutations Affect the Developing Human Brain, Memory, and Attention
Authors: Johnson Emily M , Ishak Alexandra D , Naylor Paige E , Stevenson David A , Reiss Allan L , Green Tamar
Published: June 2018

The Ras-MAPK pathway has an established role in neural development and synaptic signaling. Mutations in this pathway are associated with a collection of neurodevelopmental syndromes, Rasopathies; among these, Noonan syndrome (NS) is the most common (1:2000). Prior research has focused on identifying genetic mutations and cellular mechanisms of the disorder, however, effects of NS on the human brain remain unknown. Here, imaging and cognitive data were collected from 12 children with PTPN11-related NS, ages 4.0–11.0 years (8.98 ± 2.33) and 12 age- and sex-matched typically developing controls (8.79 ± 2.17). We observe reduced gray matter volume in bilateral corpus striatum (Cohen’s d = −1.0:−1.3), reduced surface area in temporal regions (d = −1.8:−2.2), increased cortical thickness in frontal regions (d = 1.2–1.3), and reduced cortical thickness in limbic regions (d = −1.6), including limbic structures integral to the circuitry of the hippocampus. Further, we find high levels of inattention, hyperactivity, and memory deficits in children with NS. Taken together, these results identify effects of NS on specific brain regions associated with ADHD and learning in children. While our research lays the groundwork for elucidating the neural and behavioral mechanisms of NS, it also adds an essential tier to understanding the Ras-MAPK pathway’s role in human brain development.
TRPV4 increases cardiomyocyte calcium cycling and contractility yet contributes to damage in the aged heart following hypoosmotic stress
Authors: Jones John L , Peana Deborah , Veteto Adam B , Lambert Michelle D , Nourian Zahra , Karasseva Natalia G , Hill Michael A , Lindman Brian R , Baines Christopher P , Krenz Maike , Domeier Timothy L
Published: June 2018

Aims

Cardiomyocyte Ca2+ homeostasis is altered with aging via poorly-understood mechanisms. The Transient Receptor Potential Vanilloid 4 (TRPV4) ion channel is an osmotically-activated Ca2+ channel, and there is limited information on the role of TRPV4 in cardiomyocytes. Our data show that TRPV4 protein expression increases in cardiomyocytes of the aged heart. The objective of this study was to examine the role of TRPV4 in cardiomyocyte Ca2+ homeostasis following hypoosmotic stress and to assess the contribution of TRPV4 to cardiac contractility and tissue damage following ischaemia–reperfusion (I/R), a pathological condition associated with cardiomyocyte osmotic stress.

Methods and results

TRPV4 protein expression increased in cardiomyocytes of Aged (24–27 months) mice compared with Young (3–6 months) mice. Immunohistochemistry revealed TRPV4 localization to microtubules and the t-tubule network of cardiomyocytes of Aged mice, as well as in left ventricular myocardium of elderly patients undergoing surgical aortic valve replacement for aortic stenosis. Following hypoosmotic stress, cardiomyocytes of Aged, but not Young exhibited an increase in action-potential induced Ca2+ transients. This effect was mediated via increased sarcoplasmic reticulum Ca2+ content and facilitation of Ryanodine Receptor Ca2+ release and was prevented by TRPV4 antagonism (1 μmol/L HC067047). A similar hypoosmotic stress-induced facilitation of Ca2+ transients was observed in Young transgenic mice with inducible TRPV4 expression in cardiomyocytes. Following I/R, isolated hearts of Young mice with transgenic TRPV4 expression exhibited enhanced contractility vs. hearts of Young control mice. Similarly, hearts of Aged mice exhibited enhanced contractility vs. hearts of Aged TRPV4 knock-out (TRPV4−/−) mice. In Aged, pharmacological inhibition of TRPV4 (1 μmol/L, HC067047) prevented hypoosmotic stress-induced cardiomyocyte death and I/R-induced cardiac damage.

Conclusions

Our findings provide a new mechanism for hypoosmotic stress-induced cardiomyocyte Ca2+ entry and cell damage in the aged heart. These finding have potential implications in treatment of elderly populations at increased risk of myocardial infarction and I/R injury.
Animal Models for Preclinical Development of Allogeneic Hematopoietic Cell Transplantation
Authors: Graves Scott S , Parker Maura H , Storb Rainer
Published: June 2018

Since its inception in the 1950s, hematopoietic cell transplantation (HCT) has become a highly effective clinical treatment for malignant and nonmalignant hematological disorders. This milestone in cancer therapy was only possible through decades of intensive research using murine and canine animal models that overcame what appeared in the early days to be insurmountable obstacles. Conditioning protocols for tumor ablation and immunosuppression of the recipient using irradiation and chemotherapeutic drugs were developed in mouse and dog models as well as postgrafting immunosuppression methods essential for dependable donor cell engraftment. The random-bred canine was particularly important in defining the role of histocompatibility barriers and the development of the nonmyeloablative transplantation procedure, making HCT available to elderly patients with comorbidities. Two complications limit the success of HCT: disease relapse and graft versus host disease. Studies in both mice and dogs have made significant progress toward reducing and to some degree eliminating patient morbidity and mortality associated with both disease relapse and graft versus host disease. However, more investigation is needed to make HCT more effective, safer, and available as a treatment modality for other non-life-threatening diseases such as autoimmune disorders. Here, we focus our review on the contributions made by both the murine and canine models for the successful past and future development of HCT.
An ultraspherical spectral method for linear Fredholm and Volterra integro-differential equations of convolution type
Authors: Hale Nicholas
Published: June 2018

The Legendre-based ultraspherical spectral method for ordinary differential equations (Olver, S. & Townsend, A. (2013) A fast and well-conditioned spectral method. SIAM Rev., 55, 462–489.) is combined with a formula for the convolution of two Legendre series (Hale, N. & Townsend, A. (2014a) An algorithm for the convolution of Legendre series. SIAM J. Sci. Comput., 36, A1207–A1220.) to produce a new technique for solving linear Fredholm and Volterra integro-differential equations with convolution-type kernels. When the kernel and coefficient functions are sufficiently smooth, then the method is spectrally accurate and the resulting almost-banded linear systems can be solved with linear complexity.
Persistent Complex Bereavement Disorder
Authors: Charney Meredith E. , Wieman Sarah , Leblanc Nicole , Simon Naomi
Published: June 2018

Grief is an intensely painful, but natural and normal psychological response following the death of a loved one. Although there is no uniform pattern for adapting to loss, for the majority of people, acute grief naturally evolves over time into a more integrated, less painful form of grief in a way that is healthy and adaptive; this enables return to a satisfying life without the deceased. However, a growing literature has shown that complications can arise such that the natural recovery from acute grief stalls and grief becomes persistently intense and debilitating. This chapter describes the etiology, diagnostic and clinical features, differential diagnosis, epidemiology, pathophysiology, assessment, and treatment of this condition, termed “complicated grief,” “traumatic grief,” “prolonged grief,” or “persistent complex bereavement disorder.”
Culture and Trauma-Related Disorders
Authors: Hinton Devon E. , Lewis-Fernández Roberto
Published: June 2018

This chapter examines the role of culture in trauma-related experience. Although it focuses primarily on posttraumatic stress disorder (PTSD), it proposes a model and analytic approach that will apply to other trauma-related disorders. Culture is defined here in a broad sense. However, there is considerable variation within a group, and the given examples of cultural factors prioritize intercultural variation over intracultural variation. The rest of the chapter examines PTSD from a cross-cultural perspective. A general model of culture and trauma-related disorder that is applicable to all trauma-related disorders is presented. Then the cultural influence on the rates of PTSD and on the meaning and salience of particular PTSD symptoms are reviewed, followed by a discussion of the content validity of the diagnostic category of PTSD in assessing trauma-related disorder across cultures. The chapter concludes with reflections on the clinical utility of the PTSD construct when viewed in cultural context.
PTSD in Women
Authors: Maeng Lisa Y. , Milad Mohammed R.
Published: June 2018

This chapter focuses primarily on the influence of female sex as a risk factor for posttraumatic stress disorder (PTSD). Prevalence rates suggest that women are especially vulnerable to developing PTSD. Despite changes in diagnostic criteria and examination across varied populations, the prevalence of PTSD remains consistently twice as high in women as men. This chapter examines sex differences in both incidence and presentation of PTSD. It then moves to a discussion of the neurobiological factors of PTSD in women, further examining stress and fear regulation mechanisms and the circuitry that may underlie the disproportionate vulnerability to PTSD development in women. The influence of gonadal hormones on PTSD symptomology is also explored in this chapter with a focus on estrogen and progesterone.
Susceptibility, Resilience, and Trajectories
Authors: Tsai Jack , Jones Natalie , Pietrzak Robert H. , Harpaz-Rotem Ilan , Southwick Steven M.
Published: June 2018

Nearly everyone experiences a highly stressful or traumatic event during their lifetime. However, individual responses to such events vary widely from person to person. Some people respond with symptoms of anxiety, depression, acute stress, or posttraumatic stress disorder, yet others experience minimal or no psychiatric symptoms after trauma. What makes one person more susceptible and another more resilient to the negative effects of trauma? What are the different adaptive trajectories of trauma survivors and what determines their trajectory? These are some of the questions that are examined in this chapter, which focuses on what is currently known about resilience to stress. The chapter is divided into five sections: definition, prevalence, and measurement of resilience; longitudinal studies on trajectories after trauma exposures; research on factors that are predictive of resilience and different trajectories; interventions that have been developed to increase resilience; and discussion about future directions for research on resilience.
Public Sector, Disaster, and Military Population-Based Responses to Trauma and Disaster
Authors: Ritchie Elspeth Cameron , O’Brien Kevin
Published: June 2018

This chapter focuses on systems issues for disaster outreach and intervention across the public and military public health and mental health systems. It examines how systems are organized for disasters and how community interventions are aimed to prevent or mitigate trauma-and stressor-related disorders and enhance community resilience at the population level. The chapter reviews briefly the military and associated elements of the Veterans Health Administration federal systems which has helped shape disaster response. Key innovations in disaster mental health response are outlined. The chapter describes the health care systems in the military, the Veterans Administration, and the public health sector. The authors first focus on the military, noting military resources are often called upon in civilian disasters when local response capabilities are overwhelmed. The ways in which military experience with mental health response to disaster has shaped the development of the approach to disaster response in public health systems are described.