bluuebunny/crossref_metadata_2025 huggingface dataset:
The mosquitoes of Armenia: review of knowledge and results of a field survey with first report ofAedes albopictus
Authors: Paronyan Lusine , Babayan Lilit , Manucharyan Arsen , Manukyan Dezdemonia , Vardanyan Haykuhi , Melik-Andrasyan Gayane , Schaffner Francis , Robert Vincent
Published: June 2020

Background: In 2016, a field study was implemented in all Armenian provinces in order to update knowledge on the presence and distribution of both native and invasive mosquito species. Larvae and adult mosquitoes were sampled and identified on the basis of their morphology. Supplementary field surveys were performed in 2017–2018.Results: Between June 20 and July 12, 2016, 117 localities were visited. A total number of 197 sampling units were checked, of which 143 (73%) were positive for mosquitoes (with 1–6 species per sampling unit). A total number of 4157 mosquito specimens were identified to species or species complex level. Ten species represent first records for Armenia:Aedes albopictus, Ae. annulipes, Ae. cataphylla, Ae. cinereus/geminus(probablyAe. cinereus), Ae. flavescens,Anopheles plumbeus,Coquillettidia richiardii,Culex martinii,Cx. torrentiumandCuliseta subochrea. The invasive speciesAe. albopictuswas recorded in a single locality (Bagratashen) at the border point with Georgia, along the main road Tbilisi-Yerevan. This species was further recorded in 2017 and 2018, demonstrating its establishment and spread in north Armenia. These surveys confirm the presence of vectors of malaria parasites (in particularAn. sacharovi) and West Nile virus (Cx. pipiens).Conclusion: The knowledge of the Armenian mosquito fauna is extended to a list of 28 species. The record ofAedes albopictus,an important potential vector of many arboviruses, has important implications for public health.
Endocrine Conditions and COVID-19
Authors: Shekhar Skand , Wurth Rachel , Kamilaris Crystal D. C. , Eisenhofer Graeme , Barrera Francisco J. , Hajdenberg Michelle , Tonleu Joselyne , Hall Janet E. , Schiffrin Ernesto L. , Porter Forbes , Stratakis Constantine A. , Hannah-Shmouni Fady
Published: June 2020

COVID-19 was declared a global pandemic by the WHO and has affected millions of patients around the world. COVID-19 disproportionately affects persons with endocrine conditions, thus putting them at an increased risk for severe disease. We discuss the mechanisms that place persons with endocrine conditions at an additional risk for severe COVID-19 and review the evidence. We also suggest precautions and management of endocrine conditions in the setting of global curfews being imposed and offer practical tips for uninterrupted endocrine care.
Erfahrungen von PhysiotherapeutInnen mit der Behandlung von
Covid-19-PatientInnen – eine narrative Beschreibung der Auswirkungen auf
das Personal
Authors: Best Norman , Mohring Ulrike , Glaser Alexander , Scholz Ulrike , Smolenski Ulrich Christian
Published: June 2020

Der Artikel stellt eine Zusammenfassung persönlicher
Eindrücke dar, die PhysiotherapeutInnen bei Behandlung von
COVID-19-PatientInnen auf der Intensivstation erleben. Es werden seelische
und körperliche Eindrücke geschildert und weitere
Auswirkungen auf soziale und alltägliche Belange aufgezeigt. Von
zentraler Bedeutung sind dabei weniger die Ängste, sondern eher die
Sorgen. Die Arbeit mit COVID-19-Patienten zeigt Auswirkungen auf alle
Bereich des privaten und beruflichen Umfeldes der KollegInnen.
Highly Selective Synthesis of α-Hydroxy, α-Oxy, and α-Oxo Amides by a Post-Passerini Condensation Transformation
Authors: Shiri Morteza , Gholami-Koupaei Zahra , Bandehali-Naeini Farzaneh , Tonekaboni Maryam-Sadat , Soheil-Moghaddam Saeedeh , Ebrahimi Delaram , Karami Sima , Notash Behrouz
Published: June 2020

A post-Passerini condensation transformation can be employed in the synthesis of three types of amides: α-hydroxy, α-oxy, and α-oxo amides. K2CO3 efficiently promotes the solvolysis of α-acetoxy amides to form α-hydroxy amides in methanol. 2-Acetoxy-2-(2-alkynyl­quinolin-3-yl)acetamides in basic methanol are cyclized to 1,3-dihydrofuro[3,4-b]quinoline-1-carboxamides via deacetylation and 5-exo-dig cyclization. Treatment of 2-hydroxy-2-[2-(phenylethynyl)quinolin-3-yl]acetamides with I2 in basic media produces pyrrolo[2,3-b]quinoline-2,3-diones. This cyclization involves intramolecular cyclization, dealkynylative aromatization, and oxidation of the secondary alcohol.
Radical Strategy for the Transition-Metal-Catalyzed Synthesis of γ-Lactones: A Review
Authors: Song Ren-Jie , Wei Bin , Li Ke-Wei , Wu Yan-Chen , Tong Shi-Qi
Published: June 2020

The γ-lactone skeleton is very important component of various natural products, biological molecules, food additives, and perfumes. As a result, much effort has been made towards such compounds. In this review, we summarize recent progress in transition-metal-catalyzed annulation reactions for the formation of γ-lactone derivatives through a radical pathway. Various reagents, such as anhydrides, Togni’s reagent, TMSN3, arenesulfonyl chlorides, arenediazonium salts, dibenzoyl peroxides, O-benzoylhydroxylamine, NFSI, and α-halocarboxylic compounds, used in radical cyclization reactions are described, and the mechanisms of these radical annulation reactions are also discussed.

1 Introduction

2 Annulations of Alkenes with Anhydrides

3 Annulations of Unsaturated Carboxylic Acids with Nucleophiles

4 Annulations of Alkenes with α-Halocarboxylic Compounds

5 Conclusions and Outlook
Photogrammetric Analysis of Orolabial Region in South Indians
Authors: Packiriswamy Vasanthakumar , Kumar Pramod , Bashour Mounir
Published: June 2020

In lip reconstructive surgery, knowledge of orolabial dimensions and position according to ethnicity, age, and gender are important to obtain satisfactory results. Unfortunately, there is a dearth of information related to these values in South Indians. The objective of the present study was to quantify the orolabial dimensions and position in South Indians. Evaluation of orolabial features was performed on standardized frontal and lateral of 400 South Indian subjects (200 males and 200 females), aged 18 to 30 years. The measured parameters were evaluated by an independent t-test. Significant sexual dimorphism was found in 12 of 13 measurements. Except upper lip reference to E plane, all other linear measurements such as mouth width, philtrum width, lower lip reference to E plane, upper lip height, cutaneous upper lip, upper and lower vermilion height, cutaneous lower lip height, lower lip height, and labiotragial distance were significantly greater in males than females. Angular measurements, interlabial angle, and labiomental angle were significantly greater in females. Clinically significant sexual dimorphism existed for mouth width, labiotragial distance, interlabial angle, and labiomental angle (mean difference > 3 mm). Out of the four orolabial indices, only intercanthal/mouth width indices showed a significant sexual difference. In both sexes, the triangular shape of philtral column was most common. Comparative analysis between South Indians and North American whites revealed significant differences in all measurements and some resemblance to the Han Chinese. The knowledge of the obtained mean values might be useful in the maintenance of the functional and aesthetic quality of this region during surgical planning.
Pre-pregnancy Obesity and the Risk of Peripartum Cardiomyopathy
Authors: Cho Seo-Ho , Leonard Stephanie A. , Lyndon Audrey , Main Elliott K. , Abrams Barbara , Hameed Afshan B. , Carmichael Suzan L.
Published: June 2020

Objective The aim of this study is to evaluate the contribution of pre-pregnancy obesity and overweight to peripartum cardiomyopathy.

Study Design This population-based study used linked birth record and maternal hospital discharge data from live births in California during 2007 to 2012 (n = 2,548,380). All women who had a diagnosis of peripartum cardiomyopathy during the childbirth hospitalization or who were diagnosed with peripartum cardiomyopathy during a postpartum hospital readmission within 5 months of birth were identified as cases. Pre-pregnancy body mass index (BMI, kg/m2) was classified as normal weight (18.5–24.9), overweight (25.0–29.9), obesity class 1 (30.0–34.9), obesity class 2 (35.0–39.9), and obesity class 3 (≥40). Because of small numbers, we excluded women with underweight BMI, and in some analyses, we combined obesity classes into one group. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) expressing associations between BMI and peripartum cardiomyopathy, adjusted for maternal age, race/ethnicity, education, health care payer, parity, plurality, and comorbidities.

Results The overall prevalence of peripartum cardiomyopathy during hospital admissions was 1.3 per 10,000 live births (n = 320). Unadjusted ORs were 1.32 (95% CI: 1.01–1.74) for women with overweight BMI and 2.03 (95% CI: 1.57–2.62) for women with obesity, compared with women with normal pre-pregnancy BMI. Adjusted ORs were 1.26 (95% CI: 0.95–1.66) for overweight women and 1.38 (95% CI: 1.04–1.84) for women with obesity. The ORs suggested a dose–response relationship with increasing levels of obesity, but the 95% CIs for the specific classes of obesity included 1.00.

Conclusion Pre-pregnancy obesity was associated with an increased risk of peripartum cardiomyopathy. These findings underscore the importance of BMI during pregnancy. There is a need to recognize the increased risk of peripartum cardiomyopathy in women with high BMI, especially in the late postpartum period.

Key Points
Pain after External and Endonasal Septorhinoplasty—A Propensity Score Matching Analysis
Authors: Gostian Magdalena , Loeser Johannes , Heindl Ludwig , Gostian Antoniu Oreste
Published: June 2020

Guidelines for pain management following septorhinoplasty are lacking, leading to a wide range of therapy regimes even including opioid medication. Thus, the presented study strived to investigate and compare postoperative pain intensities after external and endonasal septorhinoplasty and evaluate whether pain perception is potentially related to patient satisfaction with the aesthetic result. In addition, the effectiveness of an escalating pain treatment protocol was evaluated sparing the necessity of opioid medication. This retrospective study performed at a tertiary referral medical center includes two well-balanced groups of 54 patients each created by propensity score matching out of a total of 161 patients following external or endonasal functional septorhinoplasty performed by a single surgeon between October 1, 2011 and March 31, 2017. Pain intensity was assessed using the visual analogue scale (0–10) on the first three postoperative days (PODs) alongside with the evaluation of the analgesic score. Patients' self-reported outcome was measured with the Utrecht questionnaire, preoperatively, and 3 and 12 months, postoperatively. Postoperative mean pain sensations were similarly high following the external and endonasal approach (F
(2;190) = 2.166, p = 0.118) followed by a linear decrease over the first three PODs (F
(2;190) = 16.84, p < 0.001). Pain sensations were not related to the duration of surgery, gender, patients' age, revision surgery, and the preoperative and postoperative assessment of the nasal appearance. The consumption of metamizole (F
(1,76;172,15) = 2.83, p = 0.065) and ibuprofen (F
(2;196) = 1.037, p = 0.356) were similarly high regardless of the surgical approach. Accordingly, both the endonasal and the external approaches led to comparable postoperative pain intensities and analgesic scores. Pain was treated effectively using a standardized escalating pain treatment protocol sparing the administration of opioids. Pain was not related to patient satisfaction with the nasal appearance pre- and postsurgery.
A Safe Interval between Preoperative Intra-articular Corticosteroid Injections and Subsequent Knee Arthroscopy
Authors: Lee Wonyong , Bhattacharjee Sarah , Lee Michael J. , Ho Sherwin W. , Athiviraham Aravind , Shi Lewis L.
Published: June 2020

The purpose of this study is to evaluate the influence of intra-articular corticosteroid injections prior to knee arthroscopy on the rate of postoperative infection and define a safe timing interval between intra-articular corticosteroid injections and subsequent knee arthroscopy. The PearlDiver Database was used to identify patients who underwent a knee arthroscopy from 2007 to 2017. Patients were sorted into an injection cohort if they received any intra-articular corticosteroid injections within 6 months before surgery and a control cohort if they received no such injections. The injection cohort was then stratified into subgroups based on the timing of the most recent injection. We identified two types of postoperative infection in the 6 months following surgery: a broad definition of infection using knee infection diagnoses, and a narrow definition of infection requiring surgical treatment. The effects of the timing of preoperative corticosteroid injections on the rates of postoperative infection were investigated. The rate of broadly defined postoperative infection was significantly higher in the 0 to 2 weeks injection group (6.90%, 20/290) than the control group (2.01%, 1,449/72,089, p < 0.001; odds ratio [OR]:3.61 [95% confidence interval [CI]: 2.29, 5.70]). We observed a significant difference regarding the rate of narrowly defined postoperative infection requiring surgical treatment between the 0 and 2 weeks injection group (1.38%, 4/290) and the control group (0.27%, 192/72,089, p < 0.001, OR:5.24 [95% CI: 1.94, 14.21]). No significant differences were observed between other subgroups and the control group in both types of postoperative infection. Intra-articular corticosteroid injections within 2 weeks of knee arthroscopy were statistically significantly associated with higher rates of postoperative infection. This is a Level III, retrospective comparative study.
Unruly bodies: resistance, (in)action and hysteresis in a public health intervention
Authors: Hanckel Benjamin , Milton Sarah , Green Judith
Published: June 2020

Schools have long been sites of public health intervention on the bodies of children. Increasingly, these interventions also act on the bodies of educators. Our case study is an intervention focused on the future health of children’s bodies (‘The Daily Mile’), which, we argue, also resulted in the surveillance of educators’ bodies. We draw on Bourdieu’s concept of hysteresis to explore how those bodies can become ‘unruly’ during implementation, in both resisting and being positioned as reluctant. Hysteresis, an under-utilised Bourdieusian concept, proved useful for exploring embodiment at a point when there were mismatches between habitus and the changing field of primary education. We show how the non-participation of some actors (e.g. teachers) was positioned as part of a broader resistance to health as a dominant value, whereas non-participation of less-privileged social actors (e.g. Teaching Assistants) was problematised in different ways. We argue that attending to moments of hysteresis, in which the changing symbolic values of physical capital become explicit, surfaces not just how dominant discourses (e.g. healthism) become reproduced in fields, but also how they change and are resisted, and with what effects.
Exploring Policy Options in Regulating Rural–Urban Migration with a Bayesian Network: A Case Study in Kazakhstan
Authors: Dufhues Thomas , Buchenrieder Gertrud , Sun Zhanli
Published: June 2020

Despite the benefits associated with the free movement of people, governments often try to regulate urban immigration by constraining the agency of potential rural out-migrants in moving to cities and/or in expanding their agency to enable them to stay put. We apply an institutional framework centring on push–pull and retain–repel factors to migration intentions of potential migrants in northern Kazakhstan. We model the effects of these factors on migration intentions with Bayesian Networks and expand the baseline model with three policy scenarios. The results suggest that the effects of policies constraining urban in-migration, e.g. limiting access to affordable housing, are attenuated by social networks and reverse remittances. The supply of accessible and appropriate information on possible income and true housing costs in urban areas presents a promising road to reduce intentions of rural out-migration. Better schools and decentralised tertiary education can also reduce the migration intentions of rural residents.
Tuning carrier localization in In-rich InGaN alloys: Correlations between growth kinetics and optical properties
Authors: Kazazis Stylianos A. , Papadomanolaki Elena , Iliopoulos Eleftherios
Published: June 2020

Alloy clustering and consequent carrier localization in InGaN alloys are important aspects with large effect in materials’ optoelectronic properties and related device operation. Their importance is even higher for alloy compositions close to midrange where alloy compositional fluctuations get stronger. Such fluctuations are considered a result of thermodynamic immiscibility and indium segregation to structural defects. However, their dependence on the epitaxial growth process is unknown. Here, we examined the dependence of the degree of resulting carrier localization on growth surface kinetics in InGaN alloys developed by plasma-assisted molecular beam epitaxy. We deposited a large number of alloy thin films, heteroepitaxially on GaN(0001), under different growth temperatures and metallic surface coverage during growth but with similar compositions (∼40%), thicknesses, and growth rates. Their structure was examined by x-ray diffraction. Carrier localization phenomena were investigated employing temperature dependent photoluminescence, while spectroscopic ellipsometry was applied to determine the films’ complex dielectric function. A strong correlation of compositional uniformity and decreased carrier localization with growth conditions that reduce adatoms surface mobility and enhance “out-of-equilibrium” epitaxy character was revealed. This correlation was largely independent of the effects on films' structural properties. Thus, the importance of epitaxial surface kinetic effects on alloy clustering and localization is highlighted. These results are expected to be applicable to the entire alloy composition range and could pave the way for on demand optimal tuning of their optoelectronic properties depending on application requirements.
A model for plasma–neutral fluid interaction and its application to a study of CT formation in a magnetized Marshall gun
Authors: Dunlea Carl , Xiao Chijin , Hirose Akira
Published: June 2020

A model for plasma/neutral fluid interaction was developed and included in the implementation of non-linear MHD equations to a new code framework. The source rates of ion, electron, and neutral fluid momentum and energy due to ionization and recombination are derived using a simple method that enables the determination of the volumetric rate of thermal energy transfer from electrons to photons and neutral particles in the radiative recombination reaction. This quantity cannot be evaluated with the standard formal procedure of taking moments of the relevant collision operator and has been neglected in other studies. The plasma/neutral fluid interaction model was applied to study compact torus (CT) formation in the Super-Magnetized Ring Test (SMRT) and Spherical Compact Toroid (SPECTOR) magnetized Marshall guns, enabling clarification of the mechanisms behind the significant increases in CT electron density that are routinely observed well after formation on the SPECTOR experiment. Neutral gas, which remains concentrated below the gas valves after CT formation, diffuses up the gun barrel to the CT containment region where it is ionized, leading to the observed electron density increases. This understanding helps account for the exceptionally significant increase in temperature and the markedly reduced density, observed during the electrode edge biasing experiment conducted on SPECTOR. It is thought that edge fueling impediment, a consequence of a biasing-induced transport barrier, is largely responsible for the observed temperature increase and density decrease.
Multi-access fiber-optic time dissemination with bidirectional optical–electrical–optical nodes
Authors: Liu Ying , Wu Guiling , Zhang Hao , Zuo Faxing , Hu Liang , Chen Jianping
Published: June 2020

We first report multi-access time dissemination with bidirectional optical–electrical–optical (BOEO) nodes based on bidirectional time division multiplexing transmission over a single fiber with the same wavelength. Each BOEO node can be simultaneously served as a bidirectional amplifier, an isolator, and a multi-access time dissemination node to boost the faded bidirectional optical signals, to effectively suppress the accumulated noise along the main fiber link, and to extract synchronized time signals, respectively. We experimentally demonstrate multi-access time dissemination with two BOEO nodes in our time dissemination apparatus with the main fiber link up to 350 km. The results illustrate that stabilities in terms of time deviation of 23.2 ps at the integration time of 1 s and 3.8 ps at the integration time of 105 s, 24.3 ps at the integration time of 1 s and 1.3 ps at the integration time of 105 s, and 23.9 ps at the integration time of 1 s and 2.9 ps at the integration time of 105 s are obtained for the main link and access nodes 1 (AN1) and 2 (AN2), respectively. The proposed scheme demonstrated together with preliminary measurement results provides a guidance for future development ultra-long haul fiber-optic time dissemination with the BOEO nodes.
A high-resolution spectroscopic system for remote measurement of plasma parameters
Authors: Hyde A. , Batishchev O.
Published: June 2020

Plasma diagnostics are usually performed with immersive probes that collect the cumulative electric currents created by charged particles. Idealized models are applied to the resulting I–V curves to extract plasma flow parameters. Our non-invasive technique, based on passive emission spectroscopy (PES), allows for the remote measurement of undisturbed plasma parameters via fine spectral effects. Importantly, it can be applied to each plasma species separately, including neutral components. However, extremely high spectral resolution is required to resolve shapes of the spectral lines. We describe a portable instrumentation system that delivers sub-pm resolution in visible and near-infrared regions of the spectrum. It can be used to measure various plasma parameters but most notably allows the drift velocities of ions and neutrals to be resolved with ∼100 m/s precision. We discuss details of our experimental apparatus, along with capabilities and limitations of the PES implementation.
Berezin integral as a limit of Riemann sum
Authors: Scanlon Thomas , Sverdlov Roman
Published: June 2020

Berezin integration of functions of anticommuting Grassmann variables is usually seen as a formal operation, sometimes even defined via differentiation. Using the formalism of geometric algebra and geometric calculus in which the Grassmann numbers are endowed with a second associative product coming from a Clifford algebra structure, we show how Berezin integrals can be realized in the high dimensional limit as integrals in the sense of geometric calculus. We then show how the concepts of spinors and superspace transform into this framework.
Zebra-like patterns in whistler wave emission spectra from nonequilibrium mirror-confined laboratory plasma
Authors: Viktorov M. E. , Shalashov A. G. , Gospodchikov E. D. , Semin N. Yu. , Golubev S. V.
Published: June 2020

Zebra-like patterns have been observed in the electron cyclotron emission spectra from strongly nonequilibrium plasma confined in a table-top mirror magnetic trap. The analysis of the experimental data suggests that the formation of zebra-like patterns could eventually be related to the modulation of the whistler waves by the ion-acoustic waves excited during the abrupt ejection of electrons into a loss cone caused by the development of the whistler instability under the electron cyclotron resonance condition.
Edge expansion parallel cascade selection molecular dynamics simulation for investigating large-amplitude collective motions of proteins
Authors: Takaba Kenichiro , Tran Duy Phuoc , Kitao Akio
Published: June 2020

We propose edge expansion parallel cascade selection molecular dynamics (eePaCS-MD) as an efficient adaptive conformational sampling method to investigate the large-amplitude motions of proteins without prior knowledge of the conformational transitions. In this method, multiple independent MD simulations are iteratively conducted from initial structures randomly selected from the vertices of a multi-dimensional principal component subspace. This subspace is defined by an ensemble of protein conformations sampled during previous cycles of eePaCS-MD. The edges and vertices of the conformational subspace are determined by solving the “convex hull problem.” The sampling efficiency of eePaCS-MD is achieved by intensively repeating MD simulations from the vertex structures, which increases the probability of rare event occurrence to explore new large-amplitude collective motions. The conformational sampling efficiency of eePaCS-MD was assessed by investigating the open–close transitions of glutamine binding protein, maltose/maltodextrin binding protein, and adenylate kinase and comparing the results to those obtained using related methods. In all cases, the open–close transitions were simulated in ∼10 ns of simulation time or less, offering 1–3 orders of magnitude shorter simulation time compared to conventional MD. Furthermore, we show that the combination of eePaCS-MD and accelerated MD can further enhance conformational sampling efficiency, which reduced the total computational cost of observing the open–close transitions by at most 36%.
Symmetry of linear dielectric response tensors: Dispersion models fulfilling three fundamental conditions
Authors: Franta Daniel
Published: June 2020

Physically correct dispersion models must fulfill three fundamental conditions (time-reversal symmetry, Kramers–Kronig consistency, and conformity with sum rules). The application of these conditions on systems exhibiting low crystal symmetry, spatial dispersion, and/or magneto-optic effects is a non-trivial task. The aim of this contribution is to present an approach using decomposition of dielectric tensors into a set of independent spectral functions. For the derivation, the most general case of anisotropic dielectric response with optical activity is considered. The contribution discusses both the natural optical activity exhibiting spatial dispersion and the local magneto-optic effect of rotation of the plane of polarization induced by the external magnetic field. If the response tensor is expressed up to the term linear in the direction of the wave vector, then its symmetry can be classified into 16 types. Formulas expressing each type of the dielectric tensor using independent spectral functions are presented (the most complex case with the lowest symmetry requires 15 spectral functions). The symmetry for different internal and external conditions is demonstrated with the help of several simple models based on solving the classical equations of motion. It is shown that interpreting free particles in the magnetic field as bound particles is not correct. Instead, the Landau levels in a non-dissipative system must be interpreted as splitting of diamagnetic part of the dielectric response, rather than energy of bound states.
Split-gate cavity coupler for silicon circuit quantum electrodynamics
Authors: Borjans F. , Croot X. , Putz S. , Mi X. , Quinn S. M. , Pan A. , Kerckhoff J. , Pritchett E. J. , Jackson C. A. , Edge L. F. , Ross R. S. , Ladd T. D. , Borselli M. G. , Gyure M. F. , Petta J. R.
Published: June 2020

Coherent charge-photon and spin-photon coupling has recently been achieved in silicon double quantum dots (DQDs). Here, we demonstrate a versatile split-gate cavity-coupler that allows more than one DQD to be coupled to the same microwave cavity. Measurements of the cavity transmission as a function of level detuning yield a charge cavity coupling rate of gc/2π= 58 MHz, a charge decoherence rate of γc/2π= 36 MHz, and a cavity decay rate of κ/2π= 1.2 MHz. The charge cavity coupling rate is in good agreement with device simulations. Our coupling technique can be extended to enable simultaneous coupling of multiple DQDs to the same cavity mode, opening the door to long-range coupling of semiconductor qubits using microwave frequency photons.
Periodic hematological disorders: Quintessential examples of dynamical diseases
Authors: Mackey Michael C.
Published: June 2020

This paper summarizes the evidence supporting the classification of cyclic neutropenia as a dynamical disease and periodic chronic myelogenous leukemia is also considered. The unsatisfactory state of knowledge concerning the genesis of cyclic thrombocytopenia and periodic autoimmune hemolytic anemia is detailed.
Method to characterize a thermal diode in saturated steam atmosphere
Authors: Maier L. M. , Hess T. , Kaube A. , Corhan P. , Fitger A. , Bachmann N. , Schäfer-Welsen O. , Wöllenstein J. , Bartholomé K.
Published: June 2020

We present a novel measurement method for the characterization of thermal diodes in a saturated steam atmosphere. A measuring setup has been developed in which two pressure sensors are integrated. Using a developed analytical model, the heat flow, the volume flow, and the cracking pressure are determined from the measured absolute pressures and the pressure difference. The analytical model was verified using a flow through an orifice. We first calculated the volume flow through the orifice, with a diameter of 3 mm, using the Reader-Harris equation and then compared it to experimentally determined values. The experimentally determined values showed a discrepancy of 9%. With the measurement setup, we have characterized a check valve developed for magnetocaloric heat pumps, which has a thermally rectifying behavior. The developed check valve consists of three spring arms, which are radially attached to a valve disk. The heat flow through the check valve in the forward direction is 166 W for water, 239 W for ethanol, and 547 W for methanol at a temperature difference of 1 K. In the reverse direction, the heat flow is −0.03 W at a temperature difference of −1 K. For methanol, this corresponds to a rectification coefficient of more than 18 000.
Width dependent auto-oscillating properties of constriction based spin Hall nano-oscillators
Authors: Awad Ahmad A. , Houshang Afshin , Zahedinejad Mohammad , Khymyn Roman , Åkerman Johan
Published: June 2020

We study the current tunable microwave signal properties of nano-constriction-based spin Hall nano-oscillators in oblique magnetic fields as a function of the nano-constriction width, w=50−140 nm. The threshold current is found to scale linearly with w, defining a constant threshold current density of Jth= 1.7 × 108 A/cm2. While the current dependence of the microwave frequency shows the same generic nonmonotonic behavior for all w ⩾ 80 nm, the quality of the generated microwave signal improves strongly with w, as the total power increases and the linewidth decreases linearly with w. As a consequence, the peak power for a 140 nm nano-constriction is about an order of magnitude higher than that for an 80 nm nano-constriction. The smallest nano-constriction, w= 50 nm, exhibits a different behavior with a higher power and a worse linewidth, indicating a crossover into a qualitatively different narrow-constriction regime.
Direct evaluation of attachment and detachment rate factors of atoms in crystallizing supercooled liquids
Authors: Yarullin Dinar T. , Galimzyanov Bulat N. , Mokshin Anatolii V.
Published: June 2020

Kinetic rate factors of crystallization have a direct effect on formation and growth of an ordered solid phase in supercooled liquids and glasses. Using the crystallizing Lennard-Jones liquid as an example, in the present work, we perform a direct quantitative estimation of values of the key crystallization kinetic rate factors—the rate g+ of particle attachments to a crystalline nucleus and the rate g− of particle detachments from a nucleus. We propose a numerical approach, according to which a statistical treatment of the results of molecular dynamics simulations was performed without using any model functions and/or fitting parameters. This approach allows one to accurately estimate the critical nucleus size nc. We find that for the growing nuclei, whose sizes are larger than the critical size nc, the dependence of these kinetic rate factors on the nucleus size n follows a power law. In the case of the subnucleation regime, when the nuclei are smaller than nc, the n-dependence of the quantity g+ is strongly determined by the inherent microscopic properties of a system, and this dependence cannot be described in the framework of any universal law (for example, a power law). It has been established that the dependence of the growth rate of a crystalline nucleus on its size goes into the stationary regime at the size n > 3nc particles.
Pair-distribution-function guided optimization of fingerprints for atom-centered neural network potentials
Authors: Li Lei , Li Hao , Seymour Ieuan D. , Koziol Lucas , Henkelman Graeme
Published: June 2020

Atom-centered neural network (ANN) potentials have shown promise in computational simulations and are recognized as both efficient and sufficiently accurate to describe systems involving bond formation and breaking. A key step in the development of ANN potentials is to represent atomic coordinates as suitable inputs for a neural network, commonly described as fingerprints. The accuracy and efficiency of the ANN potentials depend strongly on the selection of these fingerprints. Here, we propose an optimization strategy of atomic fingerprints to improve the performance of ANN potentials. Specifically, a set of fingerprints is optimized to fit a set of pre-selected template functions in the f*g space, where f and g are the fingerprint and the pair distribution function for each type of interatomic interaction (e.g., a pair or 3-body). With such an optimization strategy, we have developed an ANN potential for the Pd13H2 nanoparticle system that exhibits a significant improvement to the one based upon standard template functions. We further demonstrate that the ANN potential can be used with the adaptive kinetic Monte Carlo method, which has strict requirements for the smoothness of the potential. The algorithm proposed here facilitates the development of better ANN potentials, which can broaden their application in computational simulations.
Perpendicular magnetic anisotropy in SrTiO3/Co/Pt films induced by oxygen diffusion from CaTiO3 spacer layer
Authors: Zhang Zeyu , Li Zhipeng , Meng Kangkang , Wu Yong , Chen Jikun , Xu Xiaoguang , Jiang Yong
Published: June 2020

The control of perpendicular magnetic anisotropy (PMA) of magnetic metals on a platform of perovskite oxides, especially on widely used SrTiO3 substrates, is of technological importance in integrating conventional metal spintronic devices with multifunctional perovskite oxides. In this work, we tuned the magnetic anisotropy of Co/Pt on SrTiO3 (001) substrates by inserting an interfacial calcium titanate layer with an amorphous state. The crystallinity and device microstructure were characterized by transmission electron microscopy. The Hall effect and magnetic measurement show that the PMA was achieved with the inserting layer. The electronic structure analysis by x-ray photoelectron spectroscopy suggests that out-of-plane magnetic anisotropy corresponds to the appearance of a significant density of Co–O bonding and a reduction of the Ti valence state in the calcium titanate layer. It is indicated that the amorphous calcium titanate layer could serve as an effective oxygen source to modify the chemical environment of the interfacial Co and Ti, resulting in the tuning of hybridization between Co and oxygen as well as the magnetic anisotropy. This work paves the way to engineer the magnetic anisotropy of metallic spintronic devices on the platform of perovskite oxides via oxygen diffusion for possible application in multifunctional spin orbital torque memory devices.
Laser shocking of nanocrystalline materials: Revealing the extreme pressure effects on the microstructural stability and deformation response
Authors: Hornbuckle B. C. , Dean S. W. , Zhou X. , Giri A. K. , Williams C. L. , Solanki K. N. , Thompson G. B. , Darling K. A.
Published: June 2020

We present the first results of laser-driven flyer plate experiments on a nanocrystalline copper-tantalum (NC–Cu–Ta) alloy. A pulsed Nd:YAG laser (1.2 J/pulse, 10 ns) is used to accelerate an Al foil disk (25 μm × ∼800 μm) off a glass substrate at velocities of 0.8 and 2.4 km/s through a small air gap and impact the NC–Cu–Ta target. The flyer velocities were determined from a high-speed video and extensive post-impact analyses were conducted using advanced electron microscopy revealing the formation of a band structure leading to a non-trivial upper bound for the breakdown of an extremely stable NC-microstructure and physical-properties.
Gradient-index phononic crystals for omnidirectional acoustic wave focusing and energy harvesting
Authors: Hyun Jaeyub , Park Choon-Su , Chang Jiho , Cho Wan-Ho , Kim Miso
Published: June 2020

The design, fabrication, and analysis of omnidirectional gradient-index (GRIN) phononic crystals (PnCs) for acoustic wave focusing and energy harvesting have been demonstrated both numerically and experimentally. Despite that omnidirectional functionality is a key factor to alleviate the directivity dependence issues, the concept has not yet been incorporated into acoustic energy harvesting. In this work, a symmetrical GRIN PnC structure consisting of cylinders with variation in filling fractions has been presented to tailor the spatial acoustic refractive index, thus enforcing the acoustic waves in any direction toward the targeted center area for focusing purposes. Both a numerical simulation and experimental validation confirm substantial sound energy amplification of the designed GRIN PnC over a broad frequency range from 250 Hz to 1 kHz. Notably, the maximum sound amplification occurs at the hybrid resonant frequency of the GRIN PnC structure and the acoustic duct system used to generate incident plane waves. Numerical simulation reveals that the cavity resonance and the refraction of the GRIN PnC mainly contribute to enhanced sound amplification in addition to the reflection from the acoustic duct. The GRIN PnC structure coupled with the acoustic duct system leads to enhanced harvesting output performance when integrated with a piezoelectric energy harvesting device.
A Landau–de Gennes theory for twist-bend and splay-bend nematic phases of colloidal suspensions of bent rods
Authors: Anzivino Carmine , van Roij René , Dijkstra Marjolein
Published: June 2020

We develop a phenomenological Landau–de Gennes (LdG) theory for lyotropic colloidal suspensions of bent rods using a Q-tensor expansion of the chemical-potential dependent grand potential. In addition, we introduce a bend flexoelectric term, coupling the polarization and the divergence of the Q-tensor, to study the stability of uniaxial (N), twist-bend (NTB), and splay-bend (NSB) nematic phases of colloidal bent rods. We first show that a mapping can be found between the LdG theory and the Oseen–Frank theory. By breaking the degeneracy between the splay and bend elastic constants, we find that the LdG theory predicts either an N–NTB–NSB or an N–NSB–NTB phase sequence upon increasing the particle concentration. Finally, we employ our theory to study the first-order N–NTB phase transition, for which we find that K33 as well as its renormalized version K33eff remain positive at the transition, whereas K33eff vanishes at the nematic spinodal. We connect these findings to recent simulation results.
Optimized utilization of COMB3 reactive potentials in LAMMPS
Authors: Slapikas Robert , Dabo Ismaila , Sinnott Susan B.
Published: June 2020

An investigation to optimize the application of the third-generation charge optimized many-body (COMB3) interatomic potential and associated input parameters was carried out through the study of solid–liquid interactions in classical molecular dynamics simulations. The rates of these molecular interactions are understood through the wetting rates of water nano-droplets on a bare copper (111) surface. Implementing the Langevin thermostat, the influence of simulation time step, the number of atoms in the system, the frequency at which charge equilibration is performed, and the temperature relaxation rate are all examined. The results indicate that time steps of 0.4 fs are possible when using longer relaxation times for the system temperature, which is almost double the typical time step used for reactive potentials. The use of the charge equilibration allows for a fewer atomic layers to be used in the Cu slab. In addition, charge equilibrium schemes do not need to be performed every time step to ensure accurate charge transfer. Interestingly, the rate of wetting for the nanodroplets is dominantly dependent on the temperature relaxation time, which is predicted to significantly change the viscosity of the water droplets. This work provides a pathway for optimizing simulations using the COMB3 reactive interatomic potential.
Reconstruction of the interatomic forces from dynamic scanning transmission electron microscopy data
Authors: Chakraborty M. , Ziatdinov M. , Dyck O. , Jesse S. , White A. D. , Kalinin Sergei V.
Published: June 2020

We explore the possibility for reconstruction of the generative physical models describing interactions between atomic units in solids from observational electron microscopy data. Here, scanning transmission electron microscopy (STEM) is used to observe the dynamic motion of Si atoms at the edge of monolayer graphene under continuous electron beam illumination. The resulting time-lapsed STEM images represent the snapshots of observed chemical states of the system. We use two approaches: potential of mean force calculation using a radial distribution function and a direct fitting of the graphene–Si interatomic pairwise potentials with force matching, to reconstruct the force fields in the materials. These studies lay the foundation for quantitative analysis of materials energetics from STEM data through the sampling of the metastable states in the chemical space of the system.
Transverse electric effects in charge-coupled van der Waals ribbons made of anisotropic 2D crystals
Authors: Kochelap V. A. , Sokolov V. N.
Published: June 2020

We consider van der Waals ribbons made from atomically thin charge-coupled monolayers of different anisotropies. It is found that electric fields applied to such ribbons induce macroscopically large electric effects: transverse redistributions of the carriers with formation of charged domains of enhanced and depleted electron concentrations and spatially dependent transverse electric fields different in each of the monolayers. The amplitudes of the electron redistributions are increased with an increase in the applied electric field. If V denotes the number of charge-coupled layers, in high fields, the enhanced electron concentrations in the domains can be by factor V larger than the density of initial doping, while the sizes of these domains reach 1/V-part of the ribbon width. The spatial sequence of the domains in different layers is determined by values of their anisotropy factors. We suggest that the studied transverse effects can be used for the realization of novel electrically controlled devices based on the in-plane anisotropy and charge separation.
Comparing GGA, GGA+U, and meta-GGA functionals for redox-dependent binding at open metal sites in metal–organic frameworks
Authors: Rosen Andrew S. , Notestein Justin M. , Snurr Randall Q.
Published: June 2020

Metal–organic frameworks (MOFs) with open metal sites have been widely investigated for the selective adsorption of small molecules via redox mechanisms where charge transfer can take place between the binding site and the adsorbate of interest. Quantum-chemical screening methods based on density functional theory have emerged as a promising route to accelerate the discovery of MOFs with enhanced binding affinities toward various adsorbates. However, the success of this approach is linked to the accuracy of the underlying density functional approximations (DFAs). In this work, we compare commonly used generalized gradient approximation (GGA), GGA+U, and meta-GGA exchange-correlation functionals in modeling redox-dependent binding at open metal sites in MOFs using O2 and N2 as representative small molecules. We find that the self-interaction error inherent to the widely used Perdew, Burke, and Ernzerhof (PBE) GGA predicts metal sites that are artificially redox-active, as evidenced by their strong binding affinities, short metal–adsorbate bond distances, and large degree of charge transfer. The incorporation of metal-specific, empirical Hubbard U corrections based on the transition metal oxide literature systematically reduces the redox activity of the open metal sites, often improving agreement with experiment. Additionally, the binding behavior shifts from strong chemisorption to weaker physisorption as a function of U. The M06-L meta-GGA typically predicts binding energies between those of PBE-D3(BJ) and PBE-D3(BJ)+U when using empirically derived U values from the transition metal oxide literature. Despite the strong sensitivity of the binding affinities toward a given DFA, the GGA, GGA+U, and meta-GGA approaches often yield the same qualitative trends and structure–property relationships.
Uniform potential difference scheme to evaluate effective electronic couplings for superexchange electron transfer in donor–bridge–acceptor systems
Authors: Nakano Hiroshi , Higashi Masahiro , Sato Hirofumi
Published: June 2020

This article proposes an ab initio quantum chemical method to evaluate the effective electronic coupling that determines the rate of superexchange electron transfer in donor–bridge–acceptor (D–B–A) systems. The method utilizes the fragment charge difference to define electronic diabatic states and to apply an electrostatic potential in a form of a uniform potential difference that mimics solvation effects on the relative energies of the electronic states. The two-state generalized Mulliken–Hush method is used to obtain the effective electronic coupling as the nondiagonal element of the effective Hamiltonian that is derived based on the Green’s function approach and the quasi-degenerate perturbation theory. A theoretical basis is provided for the dependence of the calculated effective electronic coupling on the applied potential and for how to find the optimal potential to give the desired effective electronic coupling that coincides with the result of the minimum energy splitting method. The method is applied to typical D–B–A molecules and gives the effective electronic couplings in reasonable agreement with the experimental estimates.