bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Trials of Adult Stuttering Treatment: Comparison of Percentage Syllables Stuttered With Self-Reported Stuttering Severity as Primary Outcomes
Authors: O'Brian Sue , Heard Rob , Onslow Mark , Packman Ann , Lowe Robyn , Menzies Ross G.
Published: May 2020

Purpose

In a companion paper, we found no statistical reason to favor percentage syllables stuttered (%SS) over parent-reported stuttering severity as a primary outcome measure for clinical trials of early stuttering. Hence, considering the logistical advantages of the latter measure, we recommended parent-reported stuttering severity for use as an outcome measure. The present report extends the prior analysis to a comparison of %SS with self-reported stuttering severity (SRSS) for use as an outcome measure in clinical trials of stuttering treatments for adults.

Method

We analyzed data from four randomized clinical trials for adults that incorporated %SS and SRSS data at prerandomization and at 6 months post randomization. We analyzed the distributions associated with the two measures, their agreement, and their estimates of effect sizes.

Results

The positively skewed distribution of %SS warrants much reservation about its value as a clinical trial outcome measure. This skew causes inherent instability because of spurious data associated with low scores, which occur commonly at the low end of such a distribution. This inherent instability is compounded by inherent problems with absolute reliability of %SS measures. These problems are reduced with the much more normal distribution of SRSS.

Conclusions

The logistical arguments in favor of SRSS apply similarly to adults as they do when parents report the stuttering severity of their children. However, there are statistical reasons to favor SRSS over %SS measures as a primary outcome of clinical trials with adult participants: SRSS has acceptable discriminant validity and a normal distribution, and it is less error prone than %SS. We recommend SRSS as a primary outcome for clinical trials of adults with stuttering.
Classroom Listening Experiences of Students Who Are Deaf or Hard of Hearing Using Listening Inventory For Education–Revised
Authors: Nelson Lauri H. , Anderson Karen , Whicker John , Barrett Tyson , Muñoz Karen , White Karl
Published: May 2020

Purpose

This study examined classroom listening experiences reported by students who are deaf or hard of hearing using the Listening Inventory For Education–Revised (LIFE-R).

Method

Retrospective electronic survey responses from 3,584 school-age participants were analyzed using descriptive statistics to report student perceptions of listening difficulty in various classroom scenarios, including the strategies students used when they did not hear or understand. Stratified data were used to explore potential differences between grades and across degree of hearing loss or type of hearing technology.

Results

Average student listening appraisal ratings for 15 classroom, school, and social scenarios was 5.7 based on a 10-point Likert scale (0 =
difficult
, 10 =
easy
), highlighting listening difficulties encountered during the school day. This finding can be considered in context with the average rating of 7.2 reported from a previous study of students with typical hearing using the LIFE-R. The greatest difficulties were reported when trying to listen when other students in the class were making noise and in hearing the comments of other classmates. Average listening difficulty was greater for respondents in Grades 3–6 than those in Grades 7–12. Listening difficulty also generally increased relative to degree of hearing loss. When unable to hear, some students took proactive steps to improve their listening access; some reported they did nothing.

Conclusions

Students who are deaf or hard of hearing can face challenges in hearing and understanding throughout the school day. A functional tool to evaluate and monitor student experiences, such as the LIFE-R, can provide information to make necessary and effective adjustments to classroom instruction and the listening environment.
Optimal Design and Application of Gas Analysis System
Authors: Li Le , Suo Jianqin , Yu Han , Zhang Longxi
Published: May 2020

To accurately measure the performance parameters of an aero-engine combustor under high-temperature and high-pressure environment, such as outlet temperature, combustion efficiency and pollutant emission, the optimal design of the existing gas sampling and analysis system was carried out, the data post-processing method was corrected, and the full-component enthalpy conservation method suitable for calculating combustor outlet temperature was established. A lean direct injection and low-pollution combustor was used to evaluate the performance and application of its gas analysis system and its data post-processing method. The investigation results indicate that the optimized gas analysis system meets the International Civil Aviation Organization's pollutant emission measurement requirements and that it has a fast response and a high data quality. The comparison of the measurement results of the gas analysis system with those of the traditional measurement methods shows that the gas analysis system has a more accurate measurement, a wider condition range and a better stability, thus accurately evaluating the outlet temperature, combustion efficiency and emission characteristics of a gas turbine combustor.
Comparative Study on Modal Decomposition Methods of Unsteady Separated Flow in Compressor Cascade
Authors: Hu Jiawei , Wang Yangang , Liu Hanru , Chen Weixiong , Xu Yong
Published: May 2020

The present work investigated the vortex structure and fluctuation frequency characteristics generated by boundary layer separation of a high-load compressor cascade using modal decomposition methods. The dominant modes and dynamic behaviors of unsteady flow in the cascade were obtained, and the differences of three modal decomposition methods (Proper Orthogonal Decomposition, Dynamic Mode Decomposition and Spectral Proper Orthogonal Decomposition) in feature recognition of cascade flow were discussed. The results show that:(1) The POD method can accurately extract the dominant spatial structure of the flow field, but the modal coefficients are multi-frequency coupled, which makes the dominant modal characteristics of cascade flow unclear. (2) The standard DMD method can obtain the spatial-temporal single frequency mode of cascade flow, as well as their growth rates and frequencies. However, this method is likely to capture the suboptimal mode of large amplitude with large attenuation rate, and fails to obtain the high-frequency coherent structure, which makes it impossible to obtain the dominant feature with limited mode number. (3) The SPOD method, based on spectral characteristics, can obtain spatial and temporal single frequency modes, and there is no modal screening problem. The use of spectral estimation method (SPOD) reduces the sensitivity to numerical noise. This method can obtain the low-rank behavior of cascade flow, which is helpful to understand cascade flow mechanisms. Therefore, SPOD method is more advantageous for the modal analysis of unsteady separated flow in high-load compressor cascade.
Cell Positioning Culture Chip Based on Functional Micro Topological Substrate
Authors: Sa Chenghua , Xue Yan , Wei Chen , Liang Haobin , Xie Li , Ye Fang
Published: May 2020

There are two main categories of cell positioning culture chips:chemical modification of surfaces and physical structure methods. The chemical methods have the advantage of providing a strong binding force, but the instability of chemical materials limits its application. The physical methods have the advantage of good stability for cell positioning, while the nonspecificity of physical structure weakens the ability to regulate cells. Here, we propose a functional micro topological chip. The chip is composed of micro-platform and micro-post array with different adhesion characteristics. At the same time, the chip is prepared by a polymer material with good biocompatibility and high chemical stability; therefore, it has the advantages of strong cell constraint ability and good localization stability. The result of chip performance verification shows that the cell localization rate of the functional micro topological chip is up to 90%, and the chip structure and dimension stability are good. The study provides an important supporting tool for the research of stem cells and their differentiation that need long-term cell culture.
Robust Adaptive Control of Hypersonic Vehicle Considering Inlet Unstart
Authors: Wang Fan , Li Hongjun , Xu Hongyang , Yan Jie , Zhang Jin
Published: May 2020

A large-scale change in the aerodynamic characteristics of the aircraft caused by the inlet unstart of the air-breathing hypersonic vehicle causes a large oscillation of the response or even a control system instability. A model reference adaptive control method considering the influence of inlet unstart is proposed. Firstly, the attitude control system is designed based on LQR-PI method for the model of inlet start, which is used as the reference model. When the inlet unstart, the model reference adaptive control is added on the basis of LQR-PI controller to improve the robustness of the system to the uncertainties caused by the inlet unstart. The method can quickly stabilize the attitude when the inlet unstart, and provides conditions for the inlet restart. Finally, the present method is verified by the simulation results. The simulation results show that when the inlet unstart, the system can re-track quickly the control command, and the steady-state error tends to zero, which verifies the effectiveness of the present method.
Design of Deep Learning VLIW Processor for Image Recognition
Authors: Li Lin , Zhang Shengbing , Wu Juan
Published: May 2020

In order to adapt the application demands of high resolution images recognition and efficient processing of localization in aviation and aerospace fields, and to solve the problem of insufficient parallelism in existing researches, an extensible multiprocessor cluster deep learning processor architecture based on VLIW is designed by optimizing the computation of each layer of deep convolutional neural network model. Parallel processing of feature maps and neurons, instruction level parallelism based on very long instruction word (VLIW), data level parallelism of multiprocessor clusters and pipeline technologies are adopted in the design. The test results based on FPGA prototype system show that the processor can effectively complete the image classification and object detection applications. The peak performance of processor is up to 128 GOP/s when it operates at 200 MHz. For selecting benchmarks, the processor speed is about 12X faster than CPU and 7X faster than GPU at least. Comparing with the results of the software framework, the average error of the test accuracy of the processor is less than 1%.
Warten lohnt sich – Kurzfortbildungen auf der NICU
Authors: Herrmann Anne , Kusma Laura , Kwiatek Astrid
Published: May 2020

Das aus Großbritannien stammende „One Minute Wonder“ findet seit Einführung der Idee in 2010 immer größere Zustimmung. Grund genug für das Autorenteam dieses Beitrags, sich näher mit der Idee zu befassen. Die Facharbeit, die diesem Beitrag zugrunde liegt, hat beim Thieme intensiv-Pflegepreis den 2. Platz erreicht.
Erfolgreiche Therapie einer Alopecia areata partim universalis mit Tofacitinib
Authors: Chapsa M. , Kuske M. , Aschoff R.
Published: May 2020

Alopecia areata ist eine T-Zell-vermittelte, nicht vernarbende Alopezie, die einen großen Einfluss auf die Lebensqualität der Patienten hat. Derzeit gibt es keine zugelassene Therapie, die eine dauerhafte Remission induziert. Kürzlich hat sich der JAK-STAT-Signalweg als mögliches therapeutisches Ziel herausgestellt, und die Ergebnisse der klinischen Studien mit oralen JAK-Inhibitoren (JAKis) zeigten sich vielversprechend. Wir berichten über einen 29-jährigen Patienten mit Alopecia areata partim universalis, der nach Versagen bisheriger Therapien probatorisch mit dem JAKi Tofacitinib behandelt wurde, worunter es zu einer anhaltenden Remission kam.
Pandemie trifft Pflegenotstand
Authors: Özlü Ismail
Published: May 2020

Seit Längerem ist auch politisch klar, dass in der Pflege Personalnotstand herrscht. CoViD-19 verschärft die Lage und öffnet damit quasi „die Büchse der Pandora“. Lesen Sie mehr darüber, welche Maßnahmen in Krisenzeiten helfen sollen und welche Rückschlüsse wir für die Zukunft der Profession ziehen müssen.
Vorbereitung auf Infektionskrankheiten wie COVID-19
Authors: Kleindieck Kristin , Hoersch Dorothea , Meck Alexandra , Merle Uta
Published: May 2020

Die SARS-CoV-2-Pandemie zieht einen erhöhten Bedarf an intensivmedizinischen Ressourcen und Versorgungsmöglichkeiten nach sich. Eine Expertengruppe formuliert auf Basis der Erfahrungen mit dem ersten Verdachtsfall SARS-CoV-2 mehrere Empfehlungen für Intensivstationen. Diese Empfehlungen enthalten Schulungen, Infektionskontrollmaßnahmen, Personalbedarf, Kommunikation und psychosoziale Unterstützung des Personals.
Co-infection of SARS CoV-2 and influenza A in a Pediatric Patient in
Germany
Authors: Wehl Goetz , Laible Monika , Rauchenzauner Markus
Published: May 2020

In December 2019 a novel coronavirus was firstly encountered in Wuhan/China
with a massive outbreak of fatal pneumonia leading to a pandemic declared by the
World Health Organization in March 2020 (WHO Dashboard COVID-19. [WHO web site].
Available from: https://www.who.int/emergencies/diseases/novel-coronavirus-2019),
affecting mainly elderly adults with underlying co-morbidities. Clinical course in
children below the age of 10 years is considered to be mild or even with subclinical
signs (Sinha IP, Ha et al. The Lancet Respiratory medicine
2020;27;S2213–2600(20) 30152-1). We describe a 4 month old infant with
co-infection of SARS CoV-2 and influenza A virus.
A Comparative Evaluation of Effects of Conventional and Herbal Irrigants on Working Length Determination by Third Generation Apex Locator–An In Vitro Study
Authors: Patalbansi Niharika , Kumar Yogesh , Jindal Neetu , Aggarwal Renu , Goyal Shefali
Published: May 2020

Introduction The establishment of accurate working length is one of the most critical steps in endodontic therapy from the biomechanical and obturation points of view. Traditionally, the use of radiography and tactile sense methods were used for working length estimation, but recently, the use of electronic apex locator (EAL) has come into existence. The aim was to evaluate the effect of conventional and herbal irrigants on working length determination by Root ZX.

Materials and Methods A total of 110 extracted single rooted teeth were taken. Standard access cavities were prepared and samples were randomly divided into 11 groups (n = 10) according to the type of irrigating solutions used. The actual root canal length was measured, and the readings in dry conditions and wet conditions were recorded. The point where Root ZX showed beep was recorded and difference was recorded as well. The recorded data was calculated and statistically analyzed using unpaired t-test.

Result In dry conditions, only saline, H2O2, Aloe vera, and green tea gave exact working length using apex locator values. Whereas in wet conditions, only Aloe vera and green tea gave exact working length.

Conclusion Although the irrigants and dry conditions influenced the results, Root ZX can be considered to be accurate, and the difference was within the clinically acceptable range and not statistically significant.
‘Terrible monsters Sin-bred’: Blakean monstrosity in Alan Moore’s graphic novels
Authors: Marchetto Santorun M. Cecilia
Published: May 2020

William Blake’s illuminated books are full of depictions of the monstrous, like Orc’s or Urizen’s metamorphoses, bestial figures such as the Leviathan in The Marriage of Heaven and Hell (c. 1790–1793), and the masses of blood and flesh appearing in The Book of Urizen (1794). In contrast to eighteenth-century discourses in which moral virtue and monstrosity were polar opposites, Blake’s universe is more complex and presents an ambivalent attitude towards revolution and social transgression embodied in the monstrous. The meanings of the monstrous in Blake are associated with evil in his works, where it can be understood as released or repressed energies, two types which correspond, respectively, to liberation or alienation. Via countercultural influence, Blakean antinomianism filtered down to Alan Moore, for whom the notion of evil depends on perspectives; thus, in Moore, the socially unacceptable can appear as monstrous, but monstrosity is also a mode through which to make visible the oppressive order that defines transgression as such. This article will discuss Blake and Moore’s use of visual and verbal aesthetics to identify as monstrous characters like Satan, Urizen and Orc in Blake and William Gull, Asmodeus and Cthulhu in Moore to pinpoint the meanings that underlie them and how the direct or indirect Blakean influence operates in Moore’s works. This will contribute to trace changes in their meanings as they pass from signifying energy to tyranny, from unfallenness to fallenness, or from conventional to visionary perception. This exploration will also show the changes in their mode of representation, contributing to understand the peculiarities of the Gothic side of Moore’s construction of Blakean vision. To do this, a series of parallels found in several examples from Alan Moore’s graphic novels will be analysed, especially Swamp Thing (1984–1987), where the hero is a vegetable–human hybrid; From Hell (1989–1998), where the villain acts as both mad scientist and monster in his perverse endeavour to violently reshape female desire to his will; Promethea (1999–2005), where a divine emanation is perceived as a threatening devil by opposing fundamentalists; and finally the horrible entities in Neonomicon (2010–2011) and Providence (2015–2017).
Effect of micropillars with varying geometry and density on the efficiency of impaction-based quartz crystal microbalance aerosol sensors
Authors: Hajizadehmotlagh Mandana , Paprotny Igor
Published: May 2020

Inertial impaction is frequently used for the collection and subsequent measurement of aerosol particles in resonator-based airborne particulate matter (PM) sensors. However, particle bounce is known to significantly reduce particle collection efficiency (CE) on surfaces exhibiting low roughness, such as those present in quartz crystal microbalance (QCM) PM sensors. This paper shows that the addition of micropillars to impaction surfaces can significantly enhance their particle collection. Similarities in particle capture mechanisms between fibrous filters and pillar-enhanced surfaces are explained, and we show the adaptability of fibrous filter theory to pillared surface collection efficiency. Experiments confirm that the micropillar cross section and spacing have a significant role in particle capture. Pillars with circular, rectangular, and cross-shaped horizontal cross sections with 15 μm height and 12 μm (dense), 20 μm (nominal), and 27 μm (sparse) center-to-center spacings were printed using two-photon micro stereolithography. The efficiency increased by 35%–52% in the dense case, while the effect of the pillar shape was negligible. At nominal spacing, CE depended heavily on the pillar shape. The cross-shaped and circular pillars improved the CE by 26%–29%, although the rectangular pillars were as efficient as the bare surface. No significant difference between the bare and pillar-enhanced surfaces was visible in sparse spacing. We further show that, upon addition of a nominal distribution of micropillars to the surface of a QCM sensor for real-time mass measurements, the sensor response improved significantly (approximately 2.5 times) compared to a QCM with a bare surface.
Extrinsic dopants in quasi-one-dimensional photovoltaic semiconductor Sb2S3: A first-principles study
Authors: Cai Zenghua , Chen Shiyou
Published: May 2020

Extrinsic elements such as C, Zn, Sn, Bi, and Ti had been doped into Sb2S3 in order to increase the electrical conductivity and thus the photovoltaic efficiency. However, the influences of these dopants are so far unclear. Using the first-principles calculations, we show that (i) Zn and Sn doping can slightly increase the p-type conductivity of Sb2S3 through forming ZnSb2 and SnSb2 acceptors, explaining the observed increase in photocurrent and carrier concentration; (ii) in contrast, the formation energies of C dopants on different sites are high, which means C doping cannot increase the conductivity of Sb2S3 obviously, so the highly reduced resistivity of C-doped Sb2S3 in experiments cannot be explained and the effects of C doping should be revisited; (iii) Bii acts as the carrier recombination center, so the photocurrent of the Bi-doped Sb2S3 solar cells decreases; and (iv) the formation energies (concentration) of Tii and TiSb1 donors are extremely low (high), so the photocurrent of the Ti doped Sb2S3 solar cells increases significantly. Considering the influences on both electrical conductivity and carrier non-radiative recombination, we propose that Pb and Cl are relatively benign p-type and n-type dopants, respectively. Cl doping can make Sb2S3 show high n-type conductivity and long minority carrier lifetime, thus offering a promising method for overcoming the current efficiency bottleneck of Sb2S3 solar cells.
Sample container for high-resolution neutron imaging of spent nuclear fuel cladding sections
Authors: Trtik Pavel , Zubler Robert , Gong Weijia , Grabherr Robin , Bertsch Johannes , Duarte Liliana I.
Published: May 2020

In this work, for the first time, high-resolution neutron imaging (true spatial resolution of 13 μm) is used for irradiated nuclear fuel cladding, applying an adapted procedure for transfer, handling, and measurements of highly radioactive samples in combination with the neutron microscope detector at Paul Scherrer Institut. A sample container referred to as an active box for high-resolution neutron imaging of highly active spent nuclear fuel cladding sections was developed. Sections of unirradiated and irradiated cladding of duplex type, having a liner, with hydrogen average concentrations of 420 wppm and 450 wppm were investigated using this device. The irradiated cladding originated from a fuel rod operated for five cycles in a Swiss pressurized water reactor. The irradiated cladding sample was measured inside the active box. Long circumferential hydride accumulations were revealed together with notable hydride precipitation at the liner–substrate interface. Measurements of the unirradiated cladding in air and inside the active box delivered consistent results, confirming the applicability of the developed device for high-resolution neutron imaging.
NWChem: Past, present, and future
Authors: Aprà E. , Bylaska E. J. , de Jong W. A. , Govind N. , Kowalski K. , Straatsma T. P. , Valiev M. , van Dam H. J. J. , Alexeev Y. , Anchell J. , Anisimov V. , Aquino F. W. , Atta-Fynn R. , Autschbach J. , Bauman N. P. , Becca J. C. , Bernholdt D. E. , Bhaskaran-Nair K. , Bogatko S. , Borowski P. , Boschen J. , Brabec J. , Bruner A. , Cauët E. , Chen Y. , Chuev G. N. , Cramer C. J. , Daily J. , Deegan M. J. O. , Dunning T. H. , Dupuis M. , Dyall K. G. , Fann G. I. , Fischer S. A. , Fonari A. , Früchtl H. , Gagliardi L. , Garza J. , Gawande N. , Ghosh S. , Glaesemann K. , Götz A. W. , Hammond J. , Helms V. , Hermes E. D. , Hirao K. , Hirata S. , Jacquelin M. , Jensen L. , Johnson B. G. , Jónsson H. , Kendall R. A. , Klemm M. , Kobayashi R. , Konkov V. , Krishnamoorthy S. , Krishnan M. , Lin Z. , Lins R. D. , Littlefield R. J. , Logsdail A. J. , Lopata K. , Ma W. , Marenich A. V. , Martin del Campo J. , Mejia-Rodriguez D. , Moore J. E. , Mullin J. M. , Nakajima T. , Nascimento D. R. , Nichols J. A. , Nichols P. J. , Nieplocha J. , Otero-de-la-Roza A. , Palmer B. , Panyala A. , Pirojsirikul T. , Peng B. , Peverati R. , Pittner J. , Pollack L. , Richard R. M. , Sadayappan P. , Schatz G. C. , Shelton W. A. , Silverstein D. W. , Smith D. M. A. , Soares T. A. , Song D. , Swart M. , Taylor H. L. , Thomas G. S. , Tipparaju V. , Truhlar D. G. , Tsemekhman K. , Van Voorhis T. , Vázquez-Mayagoitia Á. , Verma P. , Villa O. , Vishnu A. , Vogiatzis K. D. , Wang D. , Weare J. H. , Williamson M. J. , Windus T. L. , Woliński K. , Wong A. T. , Wu Q. , Yang C. , Yu Q. , Zacharias M. , Zhang Z. , Zhao Y. , Harrison R. J.
Published: May 2020

Specialized computational chemistry packages have permanently reshaped the landscape of chemical and materials science by providing tools to support and guide experimental efforts and for the prediction of atomistic and electronic properties. In this regard, electronic structure packages have played a special role by using first-principle-driven methodologies to model complex chemical and materials processes. Over the past few decades, the rapid development of computing technologies and the tremendous increase in computational power have offered a unique chance to study complex transformations using sophisticated and predictive many-body techniques that describe correlated behavior of electrons in molecular and condensed phase systems at different levels of theory. In enabling these simulations, novel parallel algorithms have been able to take advantage of computational resources to address the polynomial scaling of electronic structure methods. In this paper, we briefly review the NWChem computational chemistry suite, including its history, design principles, parallel tools, current capabilities, outreach, and outlook.
ReSpect: Relativistic spectroscopy DFT program package
Authors: Repisky Michal , Komorovsky Stanislav , Kadek Marius , Konecny Lukas , Ekström Ulf , Malkin Elena , Kaupp Martin , Ruud Kenneth , Malkina Olga L. , Malkin Vladimir G.
Published: May 2020

With the increasing interest in compounds containing heavier elements, the experimental and theoretical community requires computationally efficient approaches capable of simultaneous non-perturbative treatment of relativistic, spin-polarization, and electron correlation effects. The ReSpect program has been designed with this goal in mind and developed to perform relativistic density functional theory (DFT) calculations on molecules and solids at the quasirelativistic two-component (X2C Hamiltonian) and fully relativistic four-component (Dirac–Coulomb Hamiltonian) level of theory, including the effects of spin polarization in open-shell systems at the Kramers-unrestricted self-consistent field level. Through efficient algorithms exploiting time-reversal symmetry, biquaternion algebra, and the locality of atom-centered Gaussian-type orbitals, a significant reduction of the methodological complexity and computational cost has been achieved. This article summarizes the essential theoretical and technical advances made in the program, supplemented by example calculations. ReSpect allows molecules with >100 atoms to be efficiently handled at the four-component level of theory on standard central processing unit-based commodity clusters, at computational costs that rarely exceed a factor of 10 when compared to the non-relativistic realm. In addition to the prediction of band structures in solids, ReSpect offers a growing list of molecular spectroscopic parameters that range from electron paramagnetic resonance parameters (g-tensor, A-tensor, and zero-field splitting), via (p)NMR chemical shifts and nuclear spin–spin couplings, to various linear response properties using either conventional or damped-response time-dependent DFT (TDDFT): excitation energies, frequency-dependent polarizabilities, and natural chiroptical properties (electronic circular dichroism and optical rotatory dispersion). In addition, relativistic real-time TDDFT electron dynamics is another unique feature of the program. Documentation, including user manuals and tutorials, is available at the program’s website http://www.respectprogram.org.
Inhomogeneous probe surface induced effect in Kelvin probe force microscopy
Authors: Xu Jie , Bai Gang , Li Jinze , Li Wei
Published: May 2020

The probe in Kelvin probe force microscopy (KPFM) may have an inhomogeneous tip surface by artificial modification or by unexpected wearing or contamination. In the present work, the non-equipotential tip surface induced effect in KPFM with conducting samples was simulated by an analytical multiple-capacitances model and a numerical boundary element model, respectively. The capacitance model showed that the KPFM system satisfies the principle of superposition without couplings between the inhomogeneous tip and inhomogeneous sample induced signals. In addition, the more precise boundary element model demonstrated that the non-uniform tip surface would not change the KPFM resolution but will induce a signal shift depending on tip–sample distance, tip oscillation amplitude, and modulation mode. In the simulations, a cantilever calibration factor of 3/8 was proposed based on the Euler–Bernoulli beam theory. Our simulation result is in good agreement with a recent KPFM distance spectroscopy experiment on a silver sample, and the simulation method is also promising for the future discussion about dielectric samples.
The inhibition of concentrated active baths
Authors: Wang Chen , Jiang Hongyuan
Published: May 2020

Passive tracers in the active bath express fascinating behaviors. However, most studies are restricted to dilute active baths. Here, we use 2D simulation of suspensions consisting of active Brownian particles and a passive disk-shaped tracer to investigate tracers’ diffusive behaviors in a wide range of volume fractions. Due to the competition between the thermal noise and collisions with active particles, tracers express a first transition from the normal diffusion to the superdiffusion at a short time scale and recur to normal diffusion at a long time scale. At a low volume fraction, infrequent active collisions retard the first transition of smaller tracers. At a high volume fraction, active particles with high activity aggregating around tracers induce a bimodal probability distribution function of tracer displacements during superdiffusion. Considering the enhancement of diffusion, the non-dimensional enhanced diffusivity increases asymptotically with the Peclet number. The asymptotic line gives an upper limit of non-dimensional enhanced diffusivity of tracers. Cases with lower enhanced diffusion have a high volume fraction and a low active velocity that indicates the inhibition of concentrated active baths. With the high negentropic work of these cases, the inhibition is explained as the change of the configuration of active baths for introducing tracers.
Field emission and electron energy distributions from point-type triangular-shaped emitters made of thin graphene films
Authors: Serbun P. , Porshyn V. , Bandurin D. , Lützenkirchen-Hecht D.
Published: May 2020

We report on fabrication and detailed characterization of point-type graphene emitters, which can be further used as electron sources in modern vacuum devices. Two-dimensional free-standing and triangular-shaped field emitters with the tip angles of 30°, 60°, and 90° and a height of ∼1 mm were made of thin graphene films of varying thicknesses (2.5-μm and 8-μm). The field emission properties of these emitters were systematically investigated by different measurement techniques. Wider and thicker graphene film emitters exhibited better stability and provided higher emission currents (up to ∼100–420 μA). The short-term current fluctuations stayed within 8%–14%. The graphene film emitter with a tip angle of 90° and 8-μm thick yielded a high field emission current of up to 2.2 mA at 9 V/μm. All emitters reproducible showed a non-linear Fowler–Nordheim behavior, which was correlated with the electron energy spectroscopy results. High-resolved energy spectra showed that up to three discrete peaks can be observed from the graphene edges at currents of <1 μA. The integral energy distributions of electrons at higher currents showed single broad emission spectra with a width of up to 1–2 eV. Additionally, graphene point emitters were characterized in various vacuum environments (Xe, Ar, N2, H2, O2, and air), different pressure levels (2 × 10−4 Pa, 2 × 10−3 Pa, and 2 × 10−2 Pa), and at various distances between the anode and the graphene emitter tip. The results showed that graphene emitters can operate in non-ultrahigh vacuum conditions, and further optimization of the vacuum gap could result in a lower turn-on voltage.
Simulation study for magnetic levitation in pure water exploiting the ultra-high magnetic field gradient product of a hybrid trapped field magnet lens (HTFML)
Authors: Takahashi K. , Fujishiro H. , Ainslie M. D.
Published: May 2020

A hybrid trapped field magnet lens (HTFML) is a promising device that is able to concentrate a magnetic field higher than the applied field continuously, even after removing an external field, which was conceptually proposed by the authors in 2018. In this study, we propose a new additional advantage of the HTFML, which could be applicable for magnetic levitation and separation. The HTFML device consisting of a GdBaCuO bulk cylinder and a GdBaCuO magnetic lens, after the magnetization process from an applied field, Bapp = 10 T, can generate a maximum trapped field, Bc = 11.4 T, as well as an ultra-high magnetic field gradient product, Bz⋅dBz/dz, over ±3000 T2/m at Ts = 20 K, which is higher than that of existing superconducting magnets and large-scale hybrid magnets. Through detailed numerical simulations, the HTFML device is considered for the magnetic separation of a mixture of precious metal particles (Pt, Au, Ag, and Cu) dispersed in pure water, by exploiting the magneto-Archimedes effect. The HTFML can be realized as a compact and mobile desktop-type superconducting bulk magnet system, and there are a wide range of potential industrial applications, such as in the food and medical industries.
Molecular theory of the tilting transition and computer simulations of the tilted lamellar phase of rod–coil diblock copolymers
Authors: Osipov M. A. , Gorkunov M. V. , Berezkin A. V. , Antonov A. A. , Kudryavtsev Y. V.
Published: May 2020

Symmetric rod–coil diblock copolymers have been simulated using the method of dissipative particle dynamics in the broad range of the Flory–Huggins parameter. It has been found that the tilted lamellar phase appears to be the most stable one at strong segregation. The rod–coil copolymer tilt angle and orientational order parameters have been determined as functions of the segregation strength. The density functional theory of rod–coil diblock copolymers has been generalized to the case of the tilted lamellar phase and used to study the stability of the orthogonal lamellar phase with respect to tilt. The orthogonal phase indeed appears to be unstable in the broad region of the parameter space in the case of relatively strong segregation. It has also been shown that the transition into the tilted lamellar phase is determined by a strong coupling between two independent tilt order parameters.
Thermal metamaterials for radiative plus conductive heat flow control
Authors: Dede Ercan M. , Yu Ziqi , Schmalenberg Paul , Iizuka Hideo
Published: May 2020

In this Letter, we show that the heat transferred from a thermal composite hot body emitter may be selectively directed in the far field toward a cold body receiver of choice through the enhanced design of both the anisotropic thermal conductivity of the emitter body and its surface emissivity. Specifically, focused radiosity of a representative cylindrical emitter in a preferential direction is attained by optimizing the layout of high and low thermally conductive materials within the solid in combination with an angularly varying emissivity surface profile. The relationship between the multi-body view factor scene and the thermal metamaterial design is clarified by way of numerical experiments. Subsequent gradient-based co-optimization of the thermal composite confirms the working principles of the device and reveals non-intuitive material and surface coating layouts that further enhance the directional radiative intensity of the emitter. The principles are extendable to the engineering of arbitrarily shaped advanced composites for thermal protection systems, energy conservation, or spacecraft low-energy deep-space maneuvering by way of radiation/conduction heat flow control.
Changes in performance, egg quality and blood parameters of laying hens fed selenium and oregano oil
Authors: Reshadi H. , Torki M. , Mohammadi H.
Published: May 2020

Context Organic and herbal additives in feed may lead to more healthy animal products. For this study, we hypothesised that an organic form of selenium and/or a herbal additive (oregano, Origanum vulgare L.) may improve performance of laying hens. Aims The study was designed to determine the effects of selenium source (SS, sodium selenite; or selenium yeast, SY), oregano essential oil (OEO) and a combination of Se and OEO on performance, egg quality and blood parameters of laying hens. Methods In total, 216 Lohmann LSL-Lite laying hens, 66 weeks of age, were assigned to feed on one of six diets: control group, receiving basal diet (BD); BD + 0.3 mg SS/kg; BD + 0.3 mg SY/kg; BD + 250 mg OEO/kg; BD + 250 mg OEO + 0.3 mg SS/kg; BD + 250 mg OEO + 0.3 mg SY/kg. For each treatment, there were six replicates of six hens each for 12 weeks. Key results Feed conversion ratio was higher (P < 0.05) with the OEO diet than in the control. The SY diet decreased egg production and the OEO diet decreased egg mass (P < 0.05), although this effect was reversed with the SY + OEO diet. This would illustrate a synergistic effect of OEO with SY. Highest and lowest yolk colour values were found with the SY and SS diets, respectively (P < 0.05). Serum uric acid was lower with diets containing Se than the control diet (P < 0.05). Glutathione peroxidase activity was highest with SY and SY + OEO diets and lowest with the OEO diet (P < 0.05). Birds fed the SS + OEO diet showed the highest total antioxidant capacity and those fed SY showed the lowest total antioxidant capacity (P < 0.05). Conclusions Based on the results of the current study, it can be concluded that SY diet have increasing effect on egg weight in laying hens. In addition, novel synergistic effects between OEO and SY diets on improving egg production, egg mass and feed conversion ratio have been found. In terms of oxidative status, the detected synergistic effects between OEO and SS diets on total antioxidant capacity and between OEO and SY diets on glutathione peroxidase (GPx) have not been reported before, that appreciate more clarifying investigations in future. Although, dietary supplemental SY individually and also with OEO increased GPx, adding SS to diet together with OEO showed more improving effect on GPx compared to the separate usage. Implications Dietary supplemental SY can improve egg weight in laying hens. In addition, adding SY to diet of laying hens individually and with OEO have beneficial effects on oxidative status of bird in terms of GPs activity, which in turn can ameliorate the unfavourable impressions of probable environmentally oxidative stress on productive performance.
Barrierless Reactions of Three Benzonitrile Radical Cations with Ethylene
Authors: Shiels Oisin J. , Kelly P. D. , Blanksby Stephen J. , da Silva Gabriel , Trevitt Adam J.
Published: May 2020

Reactions of three protonated benzonitrile radical cations with ethylene are investigated. Product branching ratios and reaction kinetics, measured using ion-trap mass spectrometry, are reported and mechanisms are developed with support from quantum chemical calculations. Reactions proceed via pre-reactive van der Waals complexes with no energy barrier (above the reactant energy) and form radical addition and addition–elimination product ions. Rate coefficients are 4-dehydrobenzonitrilium: 1.72±0.01×10−11 cm3 molecule−1 s−1, 3-dehydrobenzonitrilium: 1.85±0.01×10−11 cm3 molecule−1 s−1, and 2-dehydrobenzonitrilium: 5.96±0.06×10−11 cm3 molecule−1 s−1 (with±50% absolute uncertainty). A ring-closure mechanism involving the protonated nitrile substituent is proposed for the 2-dehydrobenzonitrilium case and suggests favourable formation of the protonated indenimine cation.
E3 ligase RFWD3 is a novel modulator of stalled fork stability in BRCA2-deficient cells
Authors: Duan Haohui , Mansour Sarah , Reed Rachel , Gillis Margaret K. , Parent Benjamin , Liu Ben , Sztupinszki Zsofia , Birkbak Nicolai , Szallasi Zoltan , Elia Andrew E.H. , Garber Judy E. , Pathania Shailja
Published: May 2020

BRCA1/2 help maintain genomic integrity by stabilizing stalled forks. Here, we identify the E3 ligase RFWD3 as an essential modulator of stalled fork stability in BRCA2-deficient cells and show that codepletion of RFWD3 rescues fork degradation, collapse, and cell sensitivity upon replication stress. Stalled forks in BRCA2-deficient cells accumulate phosphorylated and ubiquitinated replication protein A (ubq-pRPA), the latter of which is mediated by RFWD3. Generation of this intermediate requires SMARCAL1, suggesting that it depends on stalled fork reversal. We show that in BRCA2-deficient cells, rescuing fork degradation might not be sufficient to ensure fork repair. Depleting MRE11 in BRCA2-deficient cells does block fork degradation, but it does not prevent fork collapse and cell sensitivity in the presence of replication stress. No such ubq-pRPA intermediate is formed in BRCA1-deficient cells, and our results suggest that BRCA1 may function upstream of BRCA2 in the stalled fork repair pathway. Collectively, our data uncover a novel mechanism by which RFWD3 destabilizes forks in BRCA2-deficient cells.
Microtubules keep large cells in shape
Authors: Meiring Joyce C.M. , Akhmanova Anna
Published: May 2020

Migrating cells need to coordinate extension and retraction of their protrusions to avoid fragmenting. Kopf et al. (2020. J. Cell Biol.https://doi.org/10.1083/jcb.201907154) demonstrate that microtubules help to maintain cell coherence during amoeboid migration by controlling actomyosin contractility in retracting protrusions.
Electron-capture decay in isotopic transfermium chains from self-consistent calculations
Authors: Sarriguren P
Published: May 2020

Weak decays in heavy nuclei with charge numbers Z = 101–109 are studied within a microscopic formalism based on deformed self-consistent Skyrme Hartree–Fock mean-field calculations with pairing correlations. The half-lives of β+ decay and electron capture are compared with α-decay half-lives obtained from phenomenological formulas. Transfermium isotopes of Md, No, Lr, Rf, Db, Sg, Bh, Hs, and Mt that can be produced in the frontier of cold and hot fusion-evaporation channels are considered. Several isotopes are identified whose β+/EC- and α-decay half-lives are comparable. The competition between these decay modes opens the possibility of new pathways towards the islands of stability.
Density compensated diodes for small field dosimetry: comprehensive testing and implications for design
Authors: Georgiou Georgios , Kumar Sudhir , Würfel Jan U , Underwood Tracy S A , Thompson James M , Hill Mark A , Rowbottom Carl G , Fenwick John D
Published: May 2020

Abstract

Purpose. In small megavoltage photon fields, the accuracies of an unmodified PTW 60017-type diode dosimeter and six diodes modified by adding airgaps of thickness 0.6–1.6 mm and diameter 3.6 mm have been comprehensively characterized experimentally and computationally. The optimally thick airgap for density compensation was determined, and detectors were micro-CT imaged to investigate differences between experimentally measured radiation responses and those predicted computationally. Methods. Detectors were tested on- and off-axis, at 5 and 15 cm depths in 6 and 15 MV fields ≥ 0.5 × 0.5 cm2. Computational studies were carried out using the EGSnrc/BEAMnrc Monte Carlo radiation transport code. Experimentally, radiation was delivered using a Varian TrueBeam linac and doses absorbed by water were measured using Gafchromic EBT3 film and ionization chambers, and compared with diode readings. Detector response was characterized via the

 

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formalism, choosing a 4 × 4 cm2 reference field. Results. For the unmodified 60017 diode, the maximum error in small field doses obtained from diode readings uncorrected by

 

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factors was determined as 11.9% computationally at +0.25 mm off-axis and 5 cm depth in a 15 MV 0.5 × 0.5 cm2 field, and 11.7% experimentally at −0.30 mm off-axis and 5 cm depth in the same field. A detector modified to include a 1.6 mm thick airgap performed best, with maximum computationally and experimentally determined errors of 2.2% and 4.1%. The 1.6 mm airgap deepened the modified dosimeter’s effective point of measurement by 0.5 mm. For some detectors significant differences existed between responses in small fields determined computationally and experimentally, micro-CT imaging indicating that these differences were due to within-tolerance variations in the thickness of an epoxy resin layer. Conclusions. The dosimetric performance of a 60017 diode detector was comprehensively improved throughout 6 and 15 MV small photon fields via density compensation. For this approach to work well with good detector-to-detector reproducibility, tolerances on dense component dimensions should be reduced to limit associated variations of response in small fields, or these components should be modified to have more water-like densities.
Estimation of the single-particle band gap and exciton binding energy in two dimensional insulators: a modified G0W0-BSE method approach
Authors: Rukelj Zoran , Despoja Vito
Published: May 2020

In this paper we present an alternative G0W0-BSE procedure, suitable for calculation of the quasi-particle and optical properties in 2D semiconductors. The method completely excludes the spurious Coulomb interaction with 2D crystal replicas. The calculated band gap energies of hexagonal boron nitride (hBN), MoS2 and MoTe2 monolayers are in good agreement with other theoretical results. The 2D Bethe–Salpeter equation is derived and reduced to a 2D-hydrogen Schrödinger equation in which enter the G0W0 band gap, DFT effective masses, and RPA screened Coulomb interaction. This formulation is applied to the problems of determining exciton binding energies and estimating the quasiparticle band gap in hBN, as well as in some transition-metal dichalcogenides. A semiclassical procedure is used in the limit of high polarizability λ in order to obtain the analytical expression for exciton binding energies.