bluuebunny/crossref_metadata_2025 huggingface dataset:
Can the Choice of Cementless Implants and Bearings during Total Hip Arthroplasty Have an Impact on the Overall Costs within a Bundled Payment Model?
Authors: Duncan Stephen , Patel Ankur , Delhougne Gary , Patrick Corey
Published: June 2020

The comprehensive care for joint replacement model from the Center for Medicare and Medicaid Services and similar programs from other payers make hospitals and health care systems more responsible for better clinical and economic outcomes of total hip arthroplasty (THA) patients. The objective of the study was to evaluate hospital-related clinical and economic outcomes of using the cementless R3 cup and Polarstem with an oxidized zirconium bearing compared with other cementless hip systems using a ceramic bearing in THA patients. We retrospectively reviewed primary THA patients from the premier perspective database between 2014 and 2018Q3. Patients with R3 cup and Polarstem with an oxidized zirconium bearing were identified using appropriate keywords from billing records and compared against cementless and ceramic-on-polyethylene (CoP) THA patients who did not meet the keywords' criteria. Patients were excluded if they were < 21 years of age; outpatient hospital discharges; evidence of revision THA; bilateral THA in same discharge or different discharges. 1:3 propensity score matching was used to control patients' demographic, clinical, and hospital characteristics. Generalized estimating equation model with appropriate distribution and link function was used to estimate hospital-related cost while logistic regression models were used to estimate discharged status, transfusion, and 30-days readmission. The study matched 818 R3/Polarstem with oxidized zirconium bearing patients with 2,454 CoP cementless THA patients. Length of stay for the R3/Polarstem patients (mean = 1.61 days; confidence interval [CI] = 1.41–1.80) was significantly lower (p-value ≤ 0.0001) than CoP THA patients (mean = 2.06 days; CI = 1.95–2.17). R3/Polarstem hip patients were 36% (odds ratio [OR] = 1.36; CI = 1.07–1.72; p-value = 0.0112) more likely to be discharged to home/home health care, 18% (OR = 0.82; CI = 0.63–1.06; p-value = 0.1235) less likely to be discharged to a skilled nursing facility (SNF), 84% less likely to have transfusion (OR = 0.16; CI = 0.09–0.29; p-value ≤ 0.0001), and 44% (OR = 0.56; CI = 0.32–0.98; p-value = 0.0412) less likely to readmitted within 30 days than CoP THA patients. Mean total hospital costs was marginally higher for R3/Polarstem patients (mean = $15,611; vs. $15,002; p-value = 0.0041) than CoP THA patients. While the total hospital costs for the R3/Polarstem was higher than CoP, the reduced length of stay, reduced discharge to SNF, and lower readmission rates can help to save money in the bundled payment and make the use of certain cementless hip systems a potential cost saving solution.
Intermittent Hypoxemia in Preterm Infants: A Potential Proinflammatory Process
Authors: Abu Jawdeh Elie G. , Huang Hong , Westgate Philip M. , Patwardhan Abhijit , Bada Henrietta , Bauer John A. , Giannone Peter
Published: June 2020

Objective A major consequence of prematurity is intermittent hypoxemia (IH). Data from both adult studies and neonatal animal models suggest that IH is proinflammatory; however, there is limited data in preterm infants. Here, we assess the relationship between IH and systemic inflammation, namely, serum C-reactive protein (CRP) in preterm infants.

Study Design Serum CRP was measured at 30 days of life, at the time of peak IH frequency. IH measures (e.g., per cent time in hypoxemia, frequency, duration) were calculated the week prior to CRP collection. Statistical analyses were based on Spearman's correlation.

Results A total of 26 infants were included. Median gestational age and birth weight were 274/7 weeks and 980 g, respectively. There were positive correlations between primary IH measures and CRP levels, especially for events longer than 1-minute duration (r range: 0.56–0.74, all p < 0.01).

Conclusion We demonstrate that IH is associated with increased CRP for the first time in preterm infants. Our findings are consistent with studies from adults and neonatal animal models suggesting that IH is a proinflammatory process.

Key Points
Quality Improvement Efforts Reduce Incidence of Surgical Necrotizing Enterocolitis and Related Deaths
Authors: Goddard Gillian R. , McNelis Kera , Poindexter Anne , Jenkins Todd , Wessel Jacqueline , Nathan Amy T. , Helmrath Michael A. , Poindexter Brenda
Published: June 2020

Objective The aim of this study was to determine whether a regional quality improvement (QI) initiative decreased incidence and severity of surgical necrotizing enterocolitis (NEC) in very low birth weight (VLBW) infants.

Study Design A retrospective review of all VLBW infants who received care at one of the three hospitals involved in a NEC QI initiative from 2011 to 2016. Primary outcome was the number of surgical NEC cases per year. Secondary outcomes included associated outcomes and mortality.

Results Sixty-three infants with either a diagnosis of Stage III NEC (n = 40) or spontaneous intestinal perforation (SIP) (n = 23) were included. The incidence of medical and surgical NEC and the mortality rate of infants with surgical NEC decreased over time. Incidence and mortality of SIP did not significantly change.

Conclusion A regional QI bundle to reduce the overall incidence of NEC also significantly decreased the incidence of surgical NEC and all-cause mortality of infants diagnosed with surgical NEC.

Key Points
Chaos and periodicities in a climatic time series of the Iberian Margin
Authors: Rojo-Garibaldi Berenice , Salas-de-León David Alberto , Monreal-Gómez María Adela , Giannerini Simone , Cartwright Julyan H. E.
Published: June 2020

We analyze the time series of the temperature of the sedimentary core MD01-2443 originating from the Iberian Margin with a duration of 420 kyr. The series has been tested for unit-root and a long term trend is estimated. We identify four significant periodicities together with a low climatic activity every 100 kyr, and these were associated with internal and external forcings. Also, we identify a high-frequency fast component that acts on top of a nonlinear, irreversible slow-changing dynamics. We find the presence of chaos in the climate of the Iberian Margin by means of a neural network asymptotic test on the largest Lyapunov exponent. The analysis suggests that the chaotic dynamics is associated with the fast high-frequency component. We also carry out a statistical analysis of the dimensionality of the attractor. Our results confirm the possibility that periodic behavior and chaos may coexist on different time scales. This could lead to different degrees of predictability in the climate system according to the characteristic time scales and/or phase-space locations.
Modulating Schottky barrier of metal/p-type 4H-SiC by thin insulator TiO2 layer intercalation
Authors: Huang Lingqin , Xia Mali , Ma Yue , Gu Xiaogang
Published: June 2020

We have investigated the barrier modulation of an electrically homogeneous Ni/p-type 4H-SiC contact by intercalation of a thin insulator TiO2 layer. It is found that the TiO2 layer can provide an extra barrier increase, resulting into the barrier height at the interface exceeding the Schottky–Mott limit. However, the barrier is inhomogeneous and Gaussianly distributed over the contact area. The barrier inhomogeneity may be due to an increase in interface states density caused by the oxide induced traps. The increase in barrier height is believed to originate from an electrostatic potential increase across the dipole layer related to the induced positive polarization charges on the p-type 4H-SiC surface.
Detailed balance for diffusion in a potential with trapping and forward–backward symmetry of trapping time distributions
Authors: Berezhkovskii Alexander M. , Makarov Dmitrii E.
Published: June 2020

For particles diffusing in a potential, detailed balance guarantees the absence of net fluxes at equilibrium. Here, we show that the conventional detailed balance condition is a special case of a more general relation that works when the diffusion occurs in the presence of a distributed sink that eventually traps the particle. We use this relation to study the lifetime distribution of particles that start and are trapped at specified initial and final points. It turns out that when the sink strength at the initial point is nonzero, the initial and final points are interchangeable, i.e., the distribution is independent of which of the two points is initial and which is final. In other words, this conditional trapping time distribution possesses forward–backward symmetry.
Second harmonic generation based joint transform correlator for human face and QR code recognitions
Authors: Hong Ling , Lin Fei , Qiu Xiaodong , Chen Lixiang
Published: June 2020

We propose a nonlinear joint transform correlator (JTC) based on a joint power spectrum via second-harmonic generation (SHG) in the Fourier domain. The fundamental waves of 1064 nm infrared light illuminate the images displayed by a single spatial light modulator. After SHG in a type-II potassium titanyl phosphate crystal in the Fourier domain, the second-harmonic wave of 532 nm visible light yields the correlation signal. We demonstrate the performance of our SHG-based JTC for human face recognition and quick response code recognition. Our work has the potential in various optical information processing applications such as infrared pattern recognition and remote sensing, security verification, target tracking, and optical computing.
Dynamic behavior of intermittent combustion oscillations in a model rocket engine combustor
Authors: Aoki Chinami , Gotoda Hiroshi , Yoshida Seiji , Tachibana Shigeru
Published: June 2020

We experimentally study the dynamic behavior of intermittent combustion oscillations by time series analysis in terms of nonlinear forecasting, symbolic dynamics, and statistical complexity, including the detection of the change in dynamical state based on symbolic dynamics and graph networks. We observe sudden switching back and forth between irregular small-amplitude and regular large-amplitude pressure fluctuations. The nonlinear local prediction method, permutation spectrum test, and the Rényi complexity–entropy curve clearly identify the possible presence of chaotic dynamics in small-amplitude pressure fluctuations during intermittent combustion oscillations. The network entropy in ordinal partition transition networks allows us to capture a significant change in dynamical state switching between chaotic oscillations and noisy limit cycle oscillations.
Dynamics editing based on offset boosting
Authors: Li Chunbiao , Lei Tengfei , Wang Xiong , Chen Guanrong
Published: June 2020

Multistability in a dynamical system has attracted great attention recently for its complex and unexpected states. Since in most chaotic systems coexisting attractors reside in their own individual basin of attraction with a fractal structure, it becomes a challenge to choose correct initial conditions to obtain desired dynamics. Selecting typical dynamics as the basic components in a dynamical sequence and then arranging them in the phase space in a desired order make the multistability transparent and controllable in the domain of initial conditions; thereafter, one can identify an attractor according to its initial sequence. Dynamics editing provides an effective technique to select typical attractors under different system parameters to form a flexible sequence in the phase space, which shows great potential for chaos-based secure communications.
Driving a magnetized domain wall in an antiferromagnet by magnons
Authors: Shen Pengtao , Tserkovnyak Yaroslav , Kim Se Kwon
Published: June 2020

We theoretically study the interaction of magnons, quanta of spin waves, and a domain wall in a one-dimensional easy-axis antiferromagnet in the presence of an external magnetic field applied along the easy axis. To this end, we begin by obtaining the exact solution for spin waves in the background of a domain wall magnetized by an external field. The finite magnetization inside the domain wall is shown to give rise to reflection of magnons scattering off the domain wall, deviating from the well-known result of reflection-free magnons in the absence of a magnetic field. For practical applications of the predicted reflection of magnons, we show that the magnon reflection contributes to the thermally driven domain-wall motion. Our work leads us to envision that inducing a finite magnetization in antiferromagnetic solitons such as vortices and skyrmions can be used to engender phenomena that do not occur in the absence of magnetization.
Structure of chalcogen overlayers on Au(111): Density functional theory and lattice-gas modeling
Authors: Liu Da-Jiang , Evans James W. , Spurgeon Peter M. , Thiel Patricia A.
Published: June 2020

Ordering of different chalcogens, S, Se, and Te, on Au(111) exhibit broad similarities but also some distinct features, which must reflect subtle differences in relative values of the long-range pair and many-body lateral interactions between adatoms. We develop lattice-gas (LG) models within a cluster expansion framework, which includes about 50 interaction parameters. These LG models are developed based on density functional theory (DFT) analysis of the energetics of key adlayer configurations in combination with the Monte Carlo (MC) simulation of the LG models to identify statistically relevant adlayer motifs, i.e., model development is based entirely on theoretical considerations. The MC simulation guides additional DFT analysis and iterative model refinement. Given their complexity, development of optimal models is also aided by strategies from supervised machine learning. The model for S successfully captures ordering motifs over a broader range of coverage than achieved by previous models, and models for Se and Te capture the features of ordering, which are distinct from those for S. More specifically, the modeling for all three chalcogens successfully explains the linear adatom rows (also subtle differences between them) observed at low coverages of ∼0.1 monolayer. The model for S also leads to a new possible explanation for the experimentally observed phase with a (5 × 5)-type low energy electron diffraction (LEED) pattern at 0.28 ML and to predictions for LEED patterns that would be observed with Se and Te at this coverage.
Al diffusion at AlN/Si interface and its suppression through substrate nitridation
Authors: Wei Lai , Yang Xuelin , Shen Jianfei , Liu Danshuo , Cai Zidong , Ma Cheng , He Xiaoguang , Tang Jun , Qi Shengli , Xu Fujun , Wang Xinqiang , Ge Weikun , Shen Bo
Published: June 2020

One of the challenges for GaN-on-Si radio frequency (RF) device applications is the RF loss, which is mainly associated with a parasitic channel formed at the interface of AlN and high-resistivity Si substrates. However, the type of conductivity and formation mechanism of the parasitic channel remains controversial. Here, we report unambiguous evidence of Al diffusion at the AlN/Si interface and its effect on RF loss. Hall measurements reveal p-type conductivity at the interface. By combining with secondary ion mass spectroscopy measurements, the p-type conductivity is attributed to the Al diffusion from the AlN layers into the Si substrates, with Al being an acceptor in Si. Experimental data and simulations are in good agreement. We also demonstrate that substrate nitridation can indeed promote the formation of an amorphous silicon nitride layer, which plays a role in suppressing the Al diffusion and, thus, reducing the RF loss.
Translational and rotational resonance frequencies of a disk in a single-axis acoustic levitator
Authors: Vieira Sílvio L. , Andrade Marco A. B.
Published: June 2020

In this study, we investigate the acoustic levitation of a disk in a single-axis acoustic levitator operating at 21.53 kHz. First, two acoustic models based on the finite element method are employed for calculating the acoustic radiation force and torque on a levitating disk. The models are also used for calculating the vertical, horizontal, and torsional trapping stiffness and its corresponding natural frequencies. Furthermore, translational and angular oscillations of the disk are captured by a high-speed camera, and a tracking algorithm is employed for extracting the natural frequencies of the oscillations. The experimental natural frequencies present good agreement with those predicted by the models. Although the numerical model was employed for simulating the forces and torques on a disk, the presented method is general and it can be employed for simulating the acoustic levitation of objects of arbitrary shapes and sizes.
Thermal properties study of silicon nanostructures by photoacoustic techniques
Authors: Dubyk K. , Nychyporuk T. , Lysenko V. , Termentzidis K. , Castanet G. , Lemoine F. , Lacroix D. , Isaiev M.
Published: June 2020

The photoacoustic method with piezoelectric detection for the simultaneous evaluation of the thermophysical properties is proposed. The approach is based on the settling of an additional heat sink for redistribution of heat fluxes deposited on the sample surface. First, the approach was tested on the porous silicon with well-defined morphology and well-studied properties. Then, heat capacity and thermal conductivity of silicon nanowire arrays were investigated by recovering the experimental data through numerical simulations. The decrease in heat capacity and effective thermal conductivity of the samples upon increasing thickness and porosity of the sample was observed. Such a behavior could be caused by the increase of the structure heterogeneity. In particular, this can be related to a larger disorder (increased density of broken nanowires and larger porosity) that appears during the etching process of the thick layers.
Pulsed RF schemes for tearing mode stabilization
Authors: Jin S. , Fisch N. J. , Reiman A. H.
Published: June 2020

The RF stabilization of tearing modes with current condensation has the potential to increase stabilization efficiency and loosen power localization requirements. Such benefits stem from the cooperative feedback between the RF deposition and the resulting island temperature perturbation governed by diffusion. A self-consistent treatment of the damping of an rf ray as it traverses the island shows that low damping scenarios can require unfavorably high powers to overcome initial power leakage and effectively capitalize on the nonlinear effect. In this work, it is demonstrated that for such regimes, modulated stabilization schemes can achieve significant improvements in heating and current drive contributions to stabilization for the same average power as a continuous wave scheme. The impact of modulation frequency and duty cycle on the performance is explored, the results of which suggest modulation strategies in which the pulsing periods are kept on the order of a diffusive time.
Design of a novel bimodal cavity
Authors: Feng H. , Huang W. , Tang C. , Li D.
Published: June 2020

Here, we introduce and analyze a novel concept of using one single cavity to support dual modes instead of using separate cavities. One advantage of using a dual-mode cavity is that only one cavity needs to be manufactured, which is space-saving and obviously economic. Apart from this, by operating both the fundamental mode and the certain harmonic mode simultaneously in one single cavity, bunch lengthening during the acceleration process could be linearly achieved, providing great potential in improving the beam brightness in linacs, storage rings, and other accelerating structures. Through the detailed design study, a structure combining the fundamental and the chosen second harmonic modes is characterized. The RF performance of the designed bimodal cavity is deeply analyzed, and it could be put into actual use for different goals to improve either the beam dynamic characteristics or the compactness of the certain system.
Dynamic characteristics of PdCoO2/β-Ga2O3 Schottky junctions
Authors: Harada T. , Tsukazaki A.
Published: June 2020

A high-frequency diode is an essential component in electrical circuits providing the current rectification function for AC/DC converters, radio frequency detectors, and automotive inverters. Schottky barrier diodes based on wide-bandgap semiconductors are promising for the high-frequency applications owing to short reverse recovery time that minimizes the energy dissipation during the switching. In this study, we report dynamic characteristics of Schottky junctions composed of a layered oxide metal PdCoO2 and an n-type β-Ga2O3 substrate. Rectifying current–voltage characteristics with reasonably small hysteresis were demonstrated up to a high frequency of 3 MHz in the PdCoO2/β-Ga2O3 Schottky junctions. For the on-state to off-state switching with the current ramp rate of approximately −2 × 1010 A/scm2, the reverse recovery time was as short as 11 ns. The short reverse recovery time was constantly obtained in the operation temperature range of 25–350 °C, showing low-loss switching properties of the PdCoO2/β-Ga2O3 Schottky junctions. The Schottky barrier height of ∼1.78 eV and the ideality factor of ∼1.06 were maintained after the 108-times on–off switching cycles. The fast switching with less energy dissipation and high durability of the PdCoO2/β-Ga2O3 Schottky junctions would be suitable for application in high-frequency power devices operating at high temperature.
Effect of memory, intolerance, and second-order reputation on cooperation
Authors: Xia Chengyi , Gracia-Lázaro Carlos , Moreno Yamir
Published: June 2020

The understanding of cooperative behavior in social systems has been the subject of intense research over the past few decades. In this regard, the theoretical models used to explain cooperation in human societies have been complemented with a growing interest in experimental studies to validate the proposed mechanisms. In this work, we rely on previous experimental findings to build a theoretical model based on two cooperation driving mechanisms: second-order reputation and memory. Specifically, taking the donation game as a starting point, the agents are distributed among three strategies, namely, unconditional cooperators, unconditional defectors, and discriminators, where the latter follow a second-order assessment rule: shunning, stern judging, image scoring, or simple standing. A discriminator will cooperate if the evaluation of the recipient’s last actions contained in his memory is above a threshold of (in)tolerance. In addition to the dynamics inherent to the game, another imitation dynamics, involving much longer times (generations), is introduced. The model is approached through a mean-field approximation that predicts the macroscopic behavior observed in Monte Carlo simulations. We found that, while in most second-order assessment rules, intolerance hinders cooperation, it has the opposite (positive) effect under the simple standing rule. Furthermore, we show that, when considering memory, the stern judging rule shows the lowest values of cooperation, while stricter rules show higher cooperation levels.
Guided matter wave inertial sensing in a miniature physics package
Authors: Nelson K. D. , Fertig C. D. , Hamilton P. , Brown J. M. , Estey B. , Müller H. , Compton R. L.
Published: June 2020

We describe an ultra-compact (∼10 cm3 physics package) inertial sensor based on atomic matter waves that are guided within an optical lattice during almost the entire interferometer cycle. We demonstrate a large momentum transfer of up to 8 ℏk photon momentum with a combination of Bragg pulses and Bloch oscillations with scalability to larger numbers of photons. Between momentum transfer steps, we maintain the atoms in a co-moving optical lattice waveguide so that the atoms are in free space only during the Bragg pulses. Our guided matter wave approach paves the way for atomic inertial sensing in dynamic environments in which untrapped atoms would otherwise quickly collide with the walls of a miniature chamber.
Thermodynamics and the structure of clusters in the dense Au vapor from molecular dynamics simulation
Authors: Zhukhovitskii D. I. , Zhakhovsky V. V.
Published: June 2020

Clusters of atoms in dense gold vapor are studied via atomistic simulation with the classical molecular dynamics method. For this purpose, we develop a new embedded atom model potential applicable to the lightest gold clusters and to the bulk gold. Simulation provides the equilibrium vapor phases at several subcritical temperatures, in which the clusters comprising up to 26 atoms are detected and analyzed. The cluster size distributions are found to match both the two-parameter model and the classical nucleation theory with the Tolman correction. For the gold liquid–vapor interface, the ratio of the Tolman length to the radius of a molecular cell in the liquid amounts to ∼0.16, almost exactly the value at which both models are identical. It is demonstrated that the lightest clusters have the chain-like structure, which is close to the freely jointed chain. Thus, the smallest clusters can be treated as the quasi-fractals with the fractal dimensionality close to two. Our analysis indicates that the cluster structural transition from the solid-like to chain-like geometry occurs in a wide temperature range around 2500 K.
Elastohydrodynamics of a deformable porous packing in a channel competing under shear and pressure gradient
Authors: Kumar Prakash , Sekhar G. P. Raja
Published: June 2020

Elastohydrodynamics of a deformable porous medium sandwiched between two parallel plates is investigated under the influence of an externally applied pressure gradient as well as an induced shear due to the movement of the upper plate. Biphasic mixture theory is used to describe the macroscopic governing equations for the fluid velocity and the solid displacement, assuming the deformable porous medium as a continuum space. The corresponding reduced mathematical model is a coupled system of elliptic partial differential equations. It is assumed that the fluid at the lower plate experiences slip due to the surface roughness of the plate. The exact solution for unidirectional fluid velocity and solid deformation resembling plain Poiseuille–Couette flow are presented for steady and unsteady states. Asymptotic analysis of the biphasic mixture in the case of low and high Darcy numbers is performed to validate the obtained solution using Prandtl’s matching technique. It is observed that the Womersley number dictates whether the fluid is trapped inside the channel or escapes the channel. The competition between the shear and the pressure gradient is analyzed, and a critical criterion is established that dictates the dominant factor. A mathematical analysis of the current problem is invaluable in understanding the mechanical behavior of biomass under pressure-driven flow in applications such as tissue engineering or shear driven flow inside endothelial glycocalyx layers, which are discussed in brief. In this context, our analysis on the extent of tissue deformation in response to frequency variations is expected to give useful insights to identify the right diagnosis.
Deterministically fabricated quantum dot single-photon source emitting indistinguishable photons in the telecom O-band
Authors: Srocka N. , Mrowiński P. , Große J. , von Helversen M. , Heindel T. , Rodt S. , Reitzenstein S.
Published: June 2020

In this work, we develop and study single-photon sources based on InGaAs quantum dots (QDs) emitting in the telecom O-band. Quantum devices are fabricated using in situ electron beam lithography in combination with thermocompression bonding to realize a backside gold mirror. Our structures are based on InGaAs/GaAs heterostructures, where the QD emission is redshifted toward the telecom O-band at 1.3 μm via a strain-reducing layer. QDs pre-selected by cathodoluminescence mapping are embedded into mesa structures with a backside gold mirror for enhanced photon-extraction efficiency. Photon-autocorrelation measurements under pulsed non-resonant wetting-layer excitation are performed at temperatures up to 40 K, showing pure single-photon emission, which makes the devices compatible with stand-alone operation using Stirling cryocoolers. Using pulsed p-shell excitation, we realize single-photon emission with a high multi-photon suppression of g(2)(0) = 0.027 ± 0.005, an as-measured two-photon interference visibility of (12 ± 4)%, a post-selected visibility of (96 ± 10)%, and an associated coherence time of (212 ± 25) ps. Moreover, the structures show an extraction efficiency of ∼5%, which is comparable to values expected from numeric simulations of this photonic structure. Further improvements of our devices will enable implementations of quantum communication via optical fibers.
Likelihood of survival of coronavirus in a respiratory droplet deposited on a solid surface
Authors: Bhardwaj Rajneesh , Agrawal Amit
Published: June 2020

We predict and analyze the drying time of respiratory droplets from a COVID-19 infected subject, which is a crucial time to infect another subject. Drying of the droplet is predicted by using a diffusion-limited evaporation model for a sessile droplet placed on a partially wetted surface with a pinned contact line. The variation in droplet volume, contact angle, ambient temperature, and humidity are considered. We analyze the chances of the survival of the virus present in the droplet based on the lifetime of the droplets under several conditions and find that the chances of the survival of the virus are strongly affected by each of these parameters. The magnitude of shear stress inside the droplet computed using the model is not large enough to obliterate the virus. We also explore the relationship between the drying time of a droplet and the growth rate of the spread of COVID-19 in five different cities and find that they are weakly correlated.
Interaction of the HCO radical with molecular hydrogen: Ab initio potential energy surface and scattering calculations
Authors: Dagdigian Paul J.
Published: June 2020

The potential energy surface describing the interaction of the HCO radical with molecular hydrogen has been computed through explicitly correlated coupled cluster calculations including single, double, and (perturbative) triple excitations [RCCSD(T)-F12a], with the assumption of fixed molecular geometries. The computed points were fit to an analytical form suitable for time-independent quantum scattering calculations of rotationally inelastic cross sections and rate coefficients. Since the spin-rotation splittings in HCO are small, cross sections for fine-structure resolved transitions are computed with electron-spin free T matrix elements through the recoupling technique usually employed to determine hyperfine-resolved cross sections. Both spin-free and fine-structure resolved state-to-state cross sections for rotationally inelastic transitions are presented and discussed.
Express determination of thickness and dielectric function of single-walled carbon nanotube films
Authors: Ermolaev Georgy A. , Tsapenko Alexey P. , Volkov Valentyn S. , Anisimov Anton S. , Gladush Yury G. , Nasibulin Albert G.
Published: June 2020

Single-walled carbon nanotube (SWCNT) films are promising building blocks for diversified applications in electronics, photovoltaics, and photonics. However, their electrical and optical engineering is still a challenging task owing to multiple obstacles, including the absence of fast and easy-to-use methods for the determination of SWCNT film properties. Here, we present a rapid, contactless, and universal technique for accurate estimation of both SWCNT film thicknesses and their dielectric functions. The approach combines broadband optical absorbance and highly sensitive spectroscopic ellipsometry measurements. The observed linear dependence of the film thickness on its absorbance at 550 nm provides a time-effective and contactless method of thickness assignment, which is of significant importance to the practical implementation of SWCNT films in optoelectronic devices. Additionally, our approach revealed that a simple procedure of film densification allows to controllably alter the dielectric response by at least 40% and, thus, to add extra fine-tuning capabilities during material property engineering. Therefore, this express technique as a whole offers an advanced metrological tool for current and next-generation SWCNT-based devices.
Reversible suppression of T cell function in the bone marrow microenvironment of acute myeloid leukemia
Authors: Lamble Adam J. , Kosaka Yoko , Laderas Ted , Maffit Allie , Kaempf Andy , Brady Lauren K. , Wang Weiwei , Long Nicola , Saultz Jennifer N. , Mori Motomi , Soong David , LeFave Clare V. , Huang Fei , Adams Homer , Loriaux Marc M. , Tognon Cristina E. , Lo Pierrette , Tyner Jeffrey W. , Fan Guang , McWeeney Shannon K. , Druker Brian J. , Lind Evan F.
Published: June 2020

Significance

Acute myeloid leukemia (AML) is the most common acute leukemia in adults, with a 5-y survival of 29%. Immunotherapy is based on the premise that tumors suppress the immune system. We investigated the status of T cell immunity in AML at the time of diagnosis. We found a significant association between T cell percentage in the bone marrow and overall survival in newly diagnosed AML patients. When we evaluated the T cells from the bone marrow of patients with AML, one-third displayed profound functional impairment. Most of these compromised T cells, however, could be rescued using checkpoint inhibitors. Our results support the development of immune checkpoint therapy to combat this deadly disease.
Elimination of rNMPs from mitochondrial DNA has no effect on its stability
Authors: Wanrooij Paulina H. , Tran Phong , Thompson Liam J. , Carvalho Gustavo , Sharma Sushma , Kreisel Katrin , Navarrete Clara , Feldberg Anna-Lena , Watt Danielle L. , Nilsson Anna Karin , Engqvist Martin K. M. , Clausen Anders R. , Chabes Andrei
Published: June 2020

Ribonucleotides (rNMPs) incorporated in the nuclear genome are a well-established threat to genome stability and can result in DNA strand breaks when not removed in a timely manner. However, the presence of a certain level of rNMPs is tolerated in mitochondrial DNA (mtDNA) although aberrant mtDNA rNMP content has been identified in disease models. We investigated the effect of incorporated rNMPs on mtDNA stability over the mouse life span and found that the mtDNA rNMP content increased during early life. The rNMP content of mtDNA varied greatly across different tissues and was defined by the rNTP/dNTP ratio of the tissue. Accordingly, mtDNA rNMPs were nearly absent in
SAMHD1

−/−

mice that have increased dNTP pools. The near absence of rNMPs did not, however, appreciably affect mtDNA copy number or the levels of mtDNA molecules with deletions or strand breaks in aged animals near the end of their life span. The physiological rNMP load therefore does not contribute to the progressive loss of mtDNA quality that occurs as mice age.
Evidence generation, decision making, and consequent growth in health disparities
Authors: Basu Anirban , Gujral Kritee
Published: June 2020

Evidence is valuable because it informs decisions to produce better outcomes. However, the same evidence that is complete for some individuals or groups may be incomplete for others, leading to inefficiencies in decision making and growth in disparities in outcomes. Specifically, the presence of treatment effect heterogeneity across some measure of baseline risk, and noisy information about such heterogeneity, can induce self-selection into randomized clinical trials (RCTs) by patients with distributions of baseline risk different from that of the target population. Consequently, average results from RCTs can disproportionately affect the treatment choices of patients with different baseline risks. Using economic models for these sequential processes of RCT enrollment, information generation, and the resulting treatment choice decisions, we show that the dynamic consequences of such information flow and behaviors may lead to growth in disparities in health outcomes across racial and ethnic categories. These disparities arise due to either the differential distribution of risk across those categories at the time RCT results are reported or the different rate of change of baseline risk over time across race and ethnicity, even though the distribution of risk within the RCT matched that of the target population when the RCT was conducted. We provide evidence on how these phenomena may have contributed to the growth in racial disparity in diabetes incidence.
Atypical protein kinase C iota (PKCλ/ι) ensures mammalian development by establishing the maternal–fetal exchange interface
Authors: Bhattacharya Bhaswati , Home Pratik , Ganguly Avishek , Ray Soma , Ghosh Ananya , Islam Md. Rashedul , French Valerie , Marsh Courtney , Gunewardena Sumedha , Okae Hiroaki , Arima Takahiro , Paul Soumen
Published: June 2020

In utero mammalian development relies on the establishment of the maternal–fetal exchange interface, which ensures transportation of nutrients and gases between the mother and the fetus. This exchange interface is established via development of multinucleated syncytiotrophoblast cells (SynTs) during placentation. In mice, SynTs develop via differentiation of the trophoblast stem cell-like progenitor cells (TSPCs) of the placenta primordium, and in humans, SynTs are developed via differentiation of villous cytotrophoblast (CTB) progenitors. Despite the critical need in pregnancy progression, conserved signaling mechanisms that ensure SynT development are poorly understood. Herein, we show that atypical protein kinase C iota (PKCλ/ι) plays an essential role in establishing the SynT differentiation program in trophoblast progenitors. Loss of PKCλ/ι in the mouse TSPCs abrogates SynT development, leading to embryonic death at approximately embryonic day 9.0 (E9.0). We also show that PKCλ/ι-mediated priming of trophoblast progenitors for SynT differentiation is a conserved event during human placentation. PKCλ/ι is selectively expressed in the first-trimester CTBs of a developing human placenta. Furthermore, loss of PKCλ/ι in CTB-derived human trophoblast stem cells (human TSCs) impairs their SynT differentiation potential both in vitro and after transplantation in immunocompromised mice. Our mechanistic analyses indicate that PKCλ/ι signaling maintains expression of GCM1, GATA2, and PPARγ, which are key transcription factors to instigate SynT differentiation programs in both mouse and human trophoblast progenitors. Our study uncovers a conserved molecular mechanism, in which PKCλ/ι signaling regulates establishment of the maternal–fetal exchange surface by promoting trophoblast progenitor-to-SynT transition during placentation.
FtsK in motion reveals its mechanism for double-stranded DNA translocation
Authors: Jean Nicolas L. , Rutherford Trevor J. , Löwe Jan
Published: June 2020

FtsK protein contains a fast DNA motor that is involved in bacterial chromosome dimer resolution. During cell division, FtsK translocates double-stranded DNA until both
dif
recombination sites are placed at mid cell for subsequent dimer resolution. Here, we solved the 3.6-Å resolution electron cryo-microscopy structure of the motor domain of FtsK while translocating on its DNA substrate. Each subunit of the homo-hexameric ring adopts a unique conformation and one of three nucleotide states. Two DNA-binding loops within four subunits form a pair of spiral staircases within the ring, interacting with the two DNA strands. This suggests that simultaneous conformational changes in all ATPase domains at each catalytic step generate movement through a mechanism related to filament treadmilling. While the ring is only rotating around the DNA slowly, it is instead the conformational states that rotate around the ring as the DNA substrate is pushed through.
Gender differences in the pathways to higher education
Authors: Stoet Gijsbert , Geary David C.
Published: June 2020

Significance

In most developed nations, fewer men than women enroll in postsecondary education, with the potential for long-term disruptions in social cohesion and economic development. The underrepresentation of men in college began in the 1990s and has frequently been discussed in national policy debates. To date, there is no comprehensive explanation as to why the underrepresentation of men is more severe in some countries than in others. Using data from 18 nations, we show that the underrepresentation of men is related both to secular changes in attitudes toward women’s education and to boys’ disadvantages in reading comprehension. Increasing men’s engagement in postsecondary education will require significant improvement in boys’ reading competencies.
Spatial confinement of receptor activity by tyrosine phosphatase during directional cell migration
Authors: Zhu Zhiwen , Chai Yongping , Hu Huifang , Li Wei , Li Wen-Jun , Dong Meng-Qiu , Wu Jia-Wei , Wang Zhi-Xin , Ou Guangshuo
Published: June 2020

Significance

A fundamental but unresolved question in directional cell migration is how a migrating cell forms only one leading edge. Here we study the activation and inhibition of an evolutionarily conserved MIG-13/LRP12-Arp2/3 signaling pathway that guides
Caenorhabditis elegans
neuroblast migration. We show that a tyrosine kinase SRC-1 directly phosphorylates MIG-13 and promotes its activity on actin assembly at the leading edge. SRC-1 and MIG-13 distribute along the entire plasma membrane, and a receptor-like tyrosine phosphatase, PTP-3, dephosphorylates SRC-1–dependent MIG-13 phosphorylation and accumulates at the rear to prevent ectopic actin polymerization. We discover that the asymmetrically localized tyrosine phosphatase spatially restricts receptor activity, thereby inhibiting ectopic polarization and secondary fronts in migrating cells.
Homoeologous exchanges occur through intragenic recombination generating novel transcripts and proteins in wheat and other polyploids
Authors: Zhang Zhibin , Gou Xiaowan , Xun Hongwei , Bian Yao , Ma Xintong , Li Juzuo , Li Ning , Gong Lei , Feldman Moshe , Liu Bao , Levy Avraham A.
Published: June 2020

Recombination between homeologous chromosomes, also known as homeologous exchange (HE), plays a significant role in shaping genome structure and gene expression in interspecific hybrids and allopolyploids of several plant species. However, the molecular mechanisms that govern HEs are not well understood. Here, we studied HE events in the progeny of a nascent allotetraploid (genome AADD) derived from two diploid progenitors of hexaploid bread wheat using cytological and whole-genome sequence analyses. In total, 37 HEs were identified and HE junctions were mapped precisely. HEs exhibit typical patterns of homologous recombination hotspots, being biased toward low-copy, subtelomeric regions of chromosome arms and showing association with known recombination hotspot motifs. But, strikingly, while homologous recombination preferentially takes place upstream and downstream of coding regions, HEs are highly enriched within gene bodies, giving rise to novel recombinant transcripts, which in turn are predicted to generate new protein fusion variants. To test whether this is a widespread phenomenon, a dataset of high-resolution HE junctions was analyzed for allopolyploid
Brassica
, rice,
Arabidopsis suecica
, banana, and peanut. Intragenic recombination and formation of chimeric genes was detected in HEs of all species and was prominent in most of them. HE thus provides a mechanism for evolutionary novelty in transcript and protein sequences in nascent allopolyploids.
Identification of chondritic krypton and xenon in Yellowstone gases and the timing of terrestrial volatile accretion
Authors: Broadley Michael W. , Barry Peter H. , Bekaert David V. , Byrne David J. , Caracausi Antonio , Ballentine Christopher J. , Marty Bernard
Published: June 2020

Significance

Volatile elements play a critical role in the evolution of Earth. Nevertheless, the mechanism(s) by which Earth acquired, and was able to preserve its volatile budget throughout its violent accretionary history, remains uncertain. In this study, we analyzed noble gas isotopes in volcanic gases from the Yellowstone mantle plume, thought to sample the deep primordial mantle, to determine the origin of volatiles on Earth. We find that Kr and Xe isotopes within the deep mantle have a similar chondritic origin to those found previously in the upper mantle. This suggests that the Earth has retained chondritic volatiles throughout the accretion and, therefore, terrestrial volatiles cannot not solely be the result of late additions following the Moon-forming impact.
Sir2 mitigates an intrinsic imbalance in origin licensing efficiency between early- and late-replicating euchromatin
Authors: Hoggard Timothy , Müller Carolin A. , Nieduszynski Conrad A. , Weinreich Michael , Fox Catherine A.
Published: June 2020

A eukaryotic chromosome relies on the function of multiple spatially distributed DNA replication origins for its stable inheritance. The spatial location of an origin is determined by the chromosomal position of an MCM complex, the inactive form of the DNA replicative helicase that is assembled onto DNA in G1-phase (also known as origin licensing). While the biochemistry of origin licensing is understood, the mechanisms that promote an adequate spatial distribution of MCM complexes across chromosomes are not. We have elucidated a role for the Sir2 histone deacetylase in establishing the normal distribution of MCM complexes across
Saccharomyces cerevisiae
chromosomes. In the absence of Sir2, MCM complexes accumulated within both early-replicating euchromatin and telomeric heterochromatin, and replication activity within these regions was enhanced. Concomitantly, the duplication of several regions of late-replicating euchromatin were delayed. Thus, Sir2-mediated attenuation of origin licensing within both euchromatin and telomeric heterochromatin established the normal spatial distribution of origins across yeast chromosomes important for normal genome duplication.
Universal vote-by-mail has no impact on partisan turnout or vote share
Authors: Thompson Daniel M. , Wu Jennifer A. , Yoder Jesse , Hall Andrew B.
Published: June 2020

In response to coronavirus disease 2019 (COVID-19), many scholars and policy makers are urging the United States to expand voting-by-mail programs to safeguard the electoral process. What are the effects of vote-by-mail? In this paper, we provide a comprehensive design-based analysis of the effect of universal vote-by-mail—a policy under which every voter is mailed a ballot in advance of the election—on electoral outcomes. We collect data from 1996 to 2018 on all three US states that implemented universal vote-by-mail in a staggered fashion across counties, allowing us to use a difference-in-differences design at the county level to estimate causal effects. We find that 1) universal vote-by-mail does not appear to affect either party’s share of turnout, 2) universal vote-by-mail does not appear to increase either party’s vote share, and 3) universal vote-by-mail modestly increases overall average turnout rates, in line with previous estimates. All three conclusions support the conventional wisdom of election administration experts and contradict many popular claims in the media.
Encrypt me! A game-based approach to Bell inequalities and quantum cryptography
Authors: López-Incera Andrea , Hartmann Andreas , Dür Wolfgang
Published: June 2020

Recent progress in the development of quantum technologies, most notably in the context of quantum computing and cryptography, poses the question of whether and how to teach the modern and sophisticated underlying theory of quantum physics, and its applications, at school. To this end, we present a game-based approach to teach Bell inequalities and quantum cryptography at undergraduate level. The approach is based on kinesthetic activities and allows students to experience and discover quantum features and their applications first-hand. The students obtain the same results as if they were in a real laboratory performing sophisticated experiments such as Bell tests, without requiring expensive tools and facilities. Specifically, quantum states are represented by the orientation of students, who also play the role of quantum particles, and mimic quantitative random behaviour and measurements using dice and apps.