bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of drag reduction effects in turbulent Taylor–Couette flow controlled via axial oscillation of inner cylinder
Authors: Yang Dandan , Gao Yanfeng , Yu Ming , Wen Xiaoping , Zhao Ming-Xiang
Published: April 2022

Analysis of drag reduction effects due to axial oscillation of an inner cylinder in a turbulent Taylor–Couette (TC) flow is performed in the present study. The frictional Reynolds number on the inner cylinder is 218, and the non-dimensional oscillating period is varied from 8 to 32. By examining turbulence statistics, we uncover different impacts of the long- and short-period oscillations on the circumferential (θ) and radial (r) velocity fluctuations in large (uθl, url) and small (uθs, urs) scales. One of the most surprising findings is that the short-period oscillation increases the large-scale Reynolds shear stress ⟨uθlurl⟩ by the strong intensification of uθl exceeding the suppression of url. To understand the phenomena, the spectra of each term in the transport equations of the Reynolds normal stresses ⟨uθ′uθ′⟩ and ⟨ur′ur′⟩ are analyzed. First, it is shown that the short-period oscillation weakens the productions of uθs, urs, and url while it enhances that of uθl. In contrast, the long-period oscillation reduces the productions of uθl and url while it mainly intensifies that of urs. Second, the investigations of the pressure–strain terms indicate that the short-period oscillation mainly impedes the inter-component energy transfer originating from the small-scale background turbulence. However, the long-period oscillation benefits the small-scale inter-component energy communication while it hinders the large-scale one. In addition, the inverse energy transfer in the turbulent TC flow is confirmed by inspecting the inter-scale energy transfer terms. The hindrance of the inter-scale energy transfer by the inner-cylinder oscillation plays a non-negligible role in the reduction of the wall friction drag.
Modeling thermodiffusion in aqueous sodium chloride solutions—Which water model is best?
Authors: Hutchinson Alice J. , Torres Juan F. , Corry Ben
Published: April 2022

Thermodiffusion is the migration of a species due to a temperature gradient and is the driving phenomenon in many applications ranging from early cancer detection to uranium enrichment. Molecular dynamics (MD) simulations can be a useful tool for exploring the rather complex thermodiffusive behavior of species, such as proteins and ions. However, current MD models of thermodiffusion in aqueous ionic solutions struggle to quantitatively predict the Soret coefficient, which indicates the magnitude and direction of species migration under a temperature gradient. In this work, we aim to improve the accuracy of MD thermodiffusion models by assessing how well different water models can recreate thermodiffusion in a benchmark aqueous NaCl solution. We tested four of the best available rigid non-polarizable water models (TIP3P-FB, TIP4P-FB, OPC3, and OPC) and the commonly used TIP3P and SPC/E water models for their ability to predict the inversion temperature and Soret coefficient in 0.5, 2, and 4M aqueous NaCl solutions. Each water model predicted a noticeably different ion distribution yielding different inversion temperatures and magnitudes of the Soret coefficient. By comparing the modeled Soret coefficients to published experimental values, we determine TIP3P-FB to be the water model that best recreates thermodiffusion in aqueous NaCl solutions. Our findings can aid future works in selecting the most accurate rigid non-polarizable water model, including water and ion parameters for investigating thermodiffusion through MD simulations.
Hot-carrier photocatalysts for artificial photosynthesis
Authors: Takeda Yasuhiko , Sato Shunsuke , Morikawa Takeshi
Published: April 2022

We applied hot-carrier extraction to particulate photocatalysts for artificial photosynthetic reactions including water splitting for H2 production and CO2 reduction to CO and HCOOH, and elucidated promising features of hot-carrier photocatalysts (HC-PCs). We designed a specific structure of the HC-PC; a semiconductor core in which thermalization of photo-generated carriers is significantly suppressed is surrounded by a shell whose bandgap is wider than that of the core. Among the photo-generated hot carriers in the core, only carriers whose energies are larger than the shell bandgap are extracted passing through the shell to the active sites on the shell surface. Thus, the shell functions as an energy-selective contact. We calculated the upper bounds of the rates of the carrier supply from the core to the active sites using a newly constructed detailed-balance model including partial thermalization and nonradiative recombination of the carriers. It has been revealed that the HC-PCs can yield higher carrier-supply rates and thus potentially higher solar-to-chemical energy conversion efficiencies for H2 and CO production than those of conventional photocatalysts with the assistance of intraband transition and Auger recombination/impact ionization. It should be noted, however, that one of the necessary conditions for efficient hot-carrier extraction is sufficiently large carrier density in the core, which, in turn, requires concentrated solar illumination by several hundreds. This would raise rate-limiting problems of activities of the chemical reactions induced by the photo-generated carriers and material-transfer properties.
Long-wave instabilities of evaporating/condensing viscous film flowing down a wavy inclined wall: Interfacial phase change effect of uniform layers
Authors: Mukhopadhyay Sanghasri , Cellier Nicolas , Mukhopadhyay Asim
Published: April 2022

The interfacial phase change effect on a thin film flowing down an undulated wall has been investigated in the present study. The study is performed for a general periodic undulated bottom of moderate steepness that is long compared to the film thickness, followed by a case study over the sinusoidal bottom. The long-wave instabilities of the ununiform film are used by deriving a nonlinear evolution equation in the classical long-wave expansion method framework. The one-equation model can track the free surface evolution and involve the bottom undulation, viscosity, gravity, surface tension, and phase change (evaporation/condensation) effects. Linear stability analysis shows that the bottom steepness ζ has a dual role. In the downhill region, increasing ζ destabilizes, whereas increasing ζ stabilizes in the uphill region. Weakly nonlinear waves are studied using the method of multiple scales to obtain the complex Ginzburg–Landau equation. The results show that both supercritical and subcritical solutions are possible for evaporating and condensate film. Interestingly, while one subcritical region is visible for an evaporating film, two subcritical unstable regions are found for condensate film. The numerical solution of the free-surface equation demonstrates the finite-amplitude behavior that tends to dry out for an evaporating film. For condensate film, the thickness increases rapidly. The rupture dynamics highly depend on the initial perturbation, and the bottom steepness has a negligible effect on it. Kutateladze number has a significant impact on the stability characteristic of the film flow as it represents a sort of efficiency of phase change that occurs at the interface.
Reduced-dimensional vibrational models of the water dimer
Authors: Vogt Emil , Simkó Irén , Császár Attila G. , Kjaergaard Henrik G.
Published: April 2022

A model based on the finite-basis representation of a vibrational Hamiltonian expressed in internal coordinates is developed. The model relies on a many-mode, low-order expansion of both the kinetic energy operator and the potential energy surface (PES). Polyad truncations and energy ceilings are used to control the size of the vibrational basis to facilitate accurate computations of the OH stretch and HOH bend intramolecular transitions of the water dimer (H216O)2. Advantages and potential pitfalls of the applied approximations are highlighted. The importance of choices related to the treatment of the kinetic energy operator in reduced-dimensional calculations and the accuracy of different water dimer PESs are discussed. A range of different reduced-dimensional computations are performed to investigate the wavenumber shifts in the intramolecular transitions caused by the coupling between the intra- and intermolecular modes. With the use of symmetry, full 12-dimensional vibrational energy levels of the water dimer are calculated, predicting accurately the experimentally observed intramolecular fundamentals. It is found that one can also predict accurate intramolecular transition wavenumbers for the water dimer by combining a set of computationally inexpensive reduced-dimensional calculations, thereby guiding future effective-Hamiltonian treatments.
Voltage-driven strain-mediated modulation of exchange bias in Ir20Mn80/Fe80Ga20/Ta/⟨011⟩-oriented PMN-32PT heterostructures
Authors: Demirci E. , de Rojas J. , Quintana A. , Fina I. , Menéndez E. , Sort J.
Published: April 2022

Manipulation of exchange bias with electric field is appealing to boost energy efficiency in spintronic devices. Here, this effect is shown at room temperature in Ir20Mn80/Fe80Ga20/Ta layers grown onto ⟨011⟩-oriented PMN-32PT single crystals. After magnetic field-cooling (FC) along the [01-1] and [100] in-plane directions of PMN-32PT and upon allowing the system to relax through consecutive hysteresis loops (training effect), the exchange bias field (HEB) is measured under the action of voltage (out-of-plane poling). Depending on the applied voltage (magnitude and sign), HEB can either increase or decrease with respect to its value at 0 V. The relative variations of HEB are 24% and 5.5% after FC along the [01-1] and [100] directions, respectively. These results stem from strain-mediated magnetoelectric coupling. The applied electric field causes changes in the coercivity and the squareness ratio of the films, suggesting a reorientation of the effective magnetic easy axis in Fe80Ga20. However, larger HEB values are observed when the squareness ratio is lower. It is claimed that the effect of voltage is equivalent to an in-plane component of an applied magnetic field oriented perpendicular to the cooling field direction. Perpendicular in-plane magnetic fields have been shown to induce an increase in exchange bias in some ferromagnetic/antiferromagnetic systems due to partial recovery of the untrained antiferromagnetic state. Remarkably, here, this effect is directly induced with voltage, therefore enhancing energy efficiency.
PET imaging of TSPO expression in immune cells can assess organ-level pathophysiology in high-consequence viral infections
Authors: Shah Swati , Sinharay Sanhita , Patel Reema , Solomon Jeffrey , Lee Ji Hyun , Schreiber-Stainthorp William , Basuli Falguni , Zhang Xiang , Hagen Katie R. , Reeder Rebecca , Wakim Paul , Huzella Louis M. , Maric Dragan , Johnson Reed F. , Hammoud Dima A.
Published: April 2022

Significance

Ebola virus (EBOV) infection is a severe, often fatal disease with poorly understood pathophysiology. Here, we performed [
18
F]-DPA-714 Positron Emission Tomography (PET) in a macaque model of EBOV infection to longitudinally track and quantify the translocator protein (TSPO), an immune cell marker. The imaging findings, along with immunohistology and other disease markers, showed increasing stem cell proliferation in the bone marrow, along with progressive monocytic and lymphocytic loss in the spleen and lungs. This study provides real-time noninvasive assessment of EBOV pathogenesis and disease progression, as well as the associated host responses, at the organ level. This approach can be similarly used to study other inflammatory and infectious diseases and to test the efficacy of newly developed therapeutics and vaccines.
IL-17–induced HIF1α drives resistance to anti–PD-L1 via fibroblast-mediated immune exclusion
Authors: Chen Xing , Zhao Junjie , Herjan Tomasz , Hong Lingzi , Liao Yun , Liu Caini , Vasu Kommireddy , Wang Han , Thompson Austin , Fox Paul L. , Gastman Brian R. , Li Xiao , Li Xiaoxia
Published: April 2022

Increasing evidence suggests that intratumoral inflammation has an outsized influence on antitumor immunity. Here, we report that IL-17, a proinflammatory cytokine widely associated with poor prognosis in solid tumors, drives the therapeutic failure of anti–PD-L1. By timing the deletion of IL-17 signaling specifically in cancer-associated fibroblasts (CAFs) in late-stage tumors, we show that IL-17 signaling drives immune exclusion by activating a collagen deposition program in murine models of cutaneous squamous cell carcinoma (cSCC). Ablation of IL-17 signaling in CAFs increased the infiltration of cytotoxic T cells into the tumor mass and sensitized otherwise resistant cSCC to anti–PD-L1 treatment. Mechanistically, the collagen deposition program in CAFs was driven by IL-17–induced translation of HIF1α, which was mediated by direct binding of Act1, the adaptor protein of IL-17 receptor, to a stem-loop structure in the 3′ untranslated region (UTR) in Hif1α mRNA. Disruption of Act1’s binding to Hif1α mRNA abolished IL-17–induced collagen deposition and enhanced anti–PD-L1–mediated tumor regression.
On almost Ehlers–Geren–Sachs theorems
Authors: Lee Ho , Nungesser Ernesto , Stalker John
Published: April 2022

We show assuming small data that massless solutions to the reflection symmetric Einstein–Vlasov system with Bianchi VII0 symmetry which are not locally rotational symmetric, can be arbitrarily close to and will remain close to isotropy as regards to the shear. However in general the shear will not tend to zero and the Hubble normalised Weyl curvature will blow up. This generalises the work (Nilsson et al 2000 Class. Quantum Grav.
17 3119–34; Wainwright et al 1999 Class. Quantum Grav.
16 2577–98), which considered a non-tilted radiation fluid to the massless Vlasov case. This represents another example of the fact that almost Ehlers–Geren–Sachs theorems do not hold in general and that collisionless matter behaves differently than a perfect fluid.
Interpreting non-semielliptical complex bands
Authors: DeGrendele Christopher J , Kazakov Jonathan A , Reuter Matthew G
Published: April 2022

Complex band structure (CBS) emerges when translational symmetry is broken and material states with complex wavevectors become admissible. The resulting complex bands continuously connect conventional bands and their shapes are directly related to measurable physical quantities. To date, interpretations of complex bands usually assume they are semielliptical because this is the shape produced by the Su–Schrieffer–Heeger (SSH) model. However, numerous studies have reported CBSs with distinctly non-semielliptical shapes, including loops (essentially deformed, asymmetric semiellipses), spikes, and vertical lines. The primary goal of this work is to explore the phenomenology of these shapes such that deeper physical insight can be obtained from a qualitative inspection of a material’s CBS. By using several variations on the SSH model, we find that (i) vertical lines are unphysical numerical artifacts, (ii) spikes indicate perfectly evanescent states in the material that couple adjacent layers but do not transfer amplitude, and (iii) asymmetric loops result from hybridization. Secondarily, we also develop a strategy for eliminating any unphysical vertical lines from calculations, thereby improving computational techniques for CBS.
KOH activated nitrogen and oxygen co-doped tubular carbon clusters as anode material for boosted potassium-ion storage capability
Authors: Zhang Ying , Tao Jie , Zhang Chenglin , Zhao Huaping , Lei Yong
Published: April 2022

Carbon nanomaterials have become a promising anode material for potassium-ion batteries (KIBs) due to their abundant resources, low cost, and excellent conductivity. However, among carbon materials, the sluggish reaction kinetics and inferior cycle life severely restrict their commercial development as KIBs anodes. It is still a huge challenge to develop carbon materials with various structural advantages and ideal electrochemical properties. Therefore, it is imperative to find a carbon material with heteroatom doping and suitable nanostructure to achieve excellent electrochemical performance. Benefiting from a Na2SO4 template-assisted method and KOH activation process, the KOH activated nitrogen and oxygen co-doped tubular carbon (KNOCTC) material with a porous structure exhibits an impressive reversible capacity of 343 mAh g−1 at 50 mA g−1 and an improved cyclability of 137 mAh g−1 at 2 A g−1 after 3000 cycles with almost no capacity decay. The kinetic analysis indicates that the storage mechanism in KNOCTC is attributed to the pseudocapacitive process during cycling. Furthermore, the new synthesis route of KNOCTC provides a new opportunity to explore carbon-based potassium storage anode materials with high capacity and cycling performance.
TiN nanobridge Josephson junctions and nanoSQUIDs on SiN-buffered Si
Authors: Faley M I , Fiadziushkin H , Frohn B , Schüffelgen P , Dunin-Borkowski R E
Published: April 2022

We report the fabrication and properties of titanium nitride (TiN) nanobridge Josephson junctions (nJJs) and nanoscale superconducting quantum interference devices (nanoSQUIDs) on SiN-buffered Si substrates. The superior corrosion resistance, large coherence length, suitable superconducting transition temperature and highly selective reactive ion etching (RIE) of TiN compared to e-beam resists and the SiN buffer layer allow for reproducible preparation and result in long-term stability of the TiN nJJs. High-resolution transmission electron microscopy reveals a columnar structure of the TiN film on an amorphous SiN buffer layer. High-resolution scanning electron microscopy reveals the variable thickness shape of the nJJs. A combination of wet etching in 20% potassium hydroxide and RIE is used for bulk nanomachining of nanoSQUID cantilevers. More than 20 oscillations of the V(B) dependence of the nanoSQUIDs with a period of ∼6 mT and hysteresis-free I(V) characteristics (CVCs) of the all-TiN nJJs are observed at 4.2 K. CVCs of the low-I
c all-TiN nJJs follow theoretical predictions for dirty superconductors down to ∼10 mK, with the critical current saturated below ∼0.6 K. These results pave the way for superconducting electronics based on nJJs operating non-hysteretically at 4.2 K, as well as for all-TiN qubits operating at sub-100 mK temperatures.
Stimulated Raman scattering induced dark pulse and microcomb generation in the mid-infrared
Authors: Liu Mulong , Huang Huimin , Lu Zhizhou , Zhou Wenquan , Wang Yuanyuan , Cai Yanan , Zhao Wei
Published: April 2022

We demonstrate that strong stimulated Raman scattering in silicon and germanium microresonators can induce stable and breathing dark pulses generation circumventing traditional complex approaches such as pump modulation and mode coupling. Although multi-photon absorption shows a small influence on the detuning value for stable dark pulse excitation, the concomitant free carrier will assist dark pulse excitation and broaden the excitation area of dark pulse thus making it easier to capture stable pulse. Furthermore, dark breather dynamics in Si and Ge are also observed, which shows distinct properties from the dark soliton breathers dominated solely by Kerr effect. Finally, we show that octave spanning mid-infrared (MIR) microcomb can be generated combining with high-order dispersion engineering, which in turn affects the breathing dynamics of dark pulses. Our findings provide another way for the initiation of dark pulses in group IV materials and broadband MIR microcomb generation for spectroscopy applications.
Electronic and optical properties of lead halide perovskite (MAPbX3) (X = I, Br, and Cl) by first principles calculations
Authors: Thatribud Abdulmutta , Rassamesard Areefen
Published: April 2022

A fundamental understanding of the size of the halide atoms in the perovskite structure is critical to optoelectric device performance. To understand the electronic and optical properties affected by the different electronegativity of the halide anions (with X = I, Br, and Cl) on the lead halide perovskite CH3NH3PbX3 (MAPbX3), were explored by density functional theory. Band structures were determined by using GGA and TB09. Optical spectra were simulated based on BSE and RPA. The influence of spin–orbit coupling (SOC) on the systems was also considered. The energy gap (Eg) of MAPbI3 is lower than that of the other two systems. Using TB09 with SOC provides a good estimate of Eg compared to the experimental values. Using RPA-TB09 provides absorption spectra that are similar to the experimental results. MAPbCl3 spectra show a strong blue shift than those of the other two. As the atomic size of the halides increases, the lattice parameters and energy gaps increase. Moreover, as the electronegativity of the halides increases, the absorption spectra shift to high energy. The inclusion of SOC provides computational results that are close to the experimental data. We have found that RPA-TB09 provides computational results that are close to the experimental data.
On Cherenkov excitation of electromagnetic waves by vortex travelling in Josephson sandwich
Authors: Malishevskii A S , Uryupin S A
Published: April 2022

The intensities of two types of Cherenkov waves arising at the motion of a solitary vortex along a Josephson sandwich are compared. These waves arise in the tail part of the vortex or are emitted deep into the medium surrounding the sandwich. The vortex velocities at which one of these two types of waves excited by the Cherenkov mechanism dominates are determined.
Hopf and quasi-periodic Hopf bifurcations and deterministic coherence in coupled Duffing-Holmes and Van der Pol oscillators: the Arnol’d resonance web
Authors: Megam Ngouonkadi E B , Kabong Nono M , Fotsin H B , Ekonde Sone M , Yemele D
Published: April 2022

A survey on coupled Van der Pol (VDP) and Duffing-Holmes (DH) oscillators, a model widely encountered in various branches of Physics and engineering is done. A bifurcation analysis of the model is presented when both unidirectional and mutual couplings are considered. It is found that stable, unstable and chaotic behaviors appear in the models. Using the method of charts of dynamics regimes in parameter planes, numerical study of the parameters space of the initial differential equations is done. Results from both approaches are compared and discussed. Features of the bifurcation picture are discussed when varying control parameters and analysis of slow-flow equations is presented. We show that the local bifurcation transition from an invariant one-torus (IT1) to an invariant two-torus (IT2) is caused by a Neimark-Saker (NS) bifurcation, also known as a one dimension-higher quasi-periodic Hopf (QH) bifurcation, these by analysing the graph of Lyapunov exponents. We observe that in the mutual coupling case, a complex structure generally-called Arnold’s resonance web phenomenon appears. Numerical simulations are compared to experimental measurements to illustrate the above behaviors. We also note the birth of coherence resonance in the slave oscillator for a certain coupling strength in the case of unidirectional coupling. We also analyze the effect of the coupling strength on the generalized synchronization between the master system and the slave system in the case of unidirectional coupling, through the concept of mutual false nearest neighbors. It allows us to understand when and how closeness in response space implies closeness in driving space.
Botanical pesticides, a potential ethnobotany Karo Regency to support food safety of the horticultural product
Authors: Sidauruk L , Panjaitan E , Sipayung P , Hutauruk S
Published: April 2022

The use of plants as materials to control pests was known by traditional communities before the introduction of synthetic pesticides. The use of botanical pesticides has received important attention along with the negative impacts of using synthetic pesticides on health and environment. In the world, Indonesia is the seventh-largest country with the number of species of plant. There are estimated more than 20,000 spesies and 25 percent of them are flowering plants. This study aims to determine the effectiveness of several native plants of Karo Regency, that have the potential as botanical pesticides to control pests in horticultural crops. Botanical pesticides are made by extraction methods, and indicator plants for observing pest attacks are potatoes. The results based on the inventory and exploration at Karo Regency, there are 12 species of plants that are most often used by farmers as botanical pesticides to control pests in horticultural crops from family Meliaceae, Solanaceae, Caricaceae, Asteraceae, Poaceae, Annonaceae, Rubiaceae, Euphorbiaceae and Amaryllidaceae. Botanical pesticide significantly reduced pest attack on plants, reduced population of Myzus pesicae and Phthorimaea operculella and increase potato yield. The most effective of botanical pesticides to control pests on potato plants were tobacco leaf extract, lemongrass extract, and soursop leaf extract, respectively.
The linkage among the agribusiness system cassava industrialization in trenggalek regency, east java, indonesia
Authors: Roidah I S , Setiawati E , Laily D W
Published: April 2022

The development of agricultural industrialization of cassava is not much running with the maximum because of the unprecedented synchronization between consumer wishes and goods produced by manufacturers. The purpose of this research was to analyze the elements’ linkages among agribusiness subsystems to encourage the success of cassava industrialization. The results showed that the linkage between agribusiness subsystems of cassava had not been applied optimally. It was because the cassava commodity was still positioned as a side crop by farmers. In addition, the industrialization of cassava required the coordination and linkage of the information that has been upstream and downstream. Thus, the input subsystem, production subsystem, and marketing subsystem must be observed by farmers to increase income.
Study on mechanism of sidewall roughness scattering in slot optical waveguides by FDTD simulation
Authors: Wang Yu , Xu Yameng , Hu Kangyong , Zhu Xuyang , Kong Mei
Published: April 2022

The slot optical waveguide is different from the conventional solid-core optical waveguide in both structure and features and has many unique and important applications. However, serious sidewall roughness scattering (SRS) loss limits the performance of the devices based on it. So far, the mechanism of the SRS in the slot waveguide is still not clear, and it seems not reasonable to analyze it directly by the Bragg diffraction condition. In this paper, through finite-difference time-domain simulation, we demonstrate that the regimes of the SRS and backscattering in the slot waveguide are the same as those of the solid-core waveguide, and the conditions of the diffraction radiation caused by the outer and the inner sidewalls are the same. The rationality of these conclusions are explained by taking the slot waveguide as a whole. The scattering regimes revealed and verified in this paper will benefit the suppression of the SRS loss and the utilization of the slot waveguide.
Multi-frequency coherent perfect absorption in the one-dimensional magnetized ferrite photonic structure
Authors: Zhang Yang , Wan Baofei , Zhang Hao , Zhang Haifeng
Published: April 2022

A controllable multi-frequency absorption structure predicated on a one-dimensional magnetized ferrite photonic crystals (MFPCs) that achieves coherent perfect absorption is designed and further analyzed by utilizing the transfer matrix method. By introducing the filter structures to the MFPC and using the gradient descent optimization algorithms to optimize its layer parameters, the multi-frequency coherent absorption curve is obtained. The suggested MFPC brings out about six absorption peaks whose absorptance can be higher than 0.99 at the same time under the transverse electric mode. Moreover, the absorptance can be regulated from 0.99 to less than 0.1 by merely changing the phase deviation between the two incident waves to the front and rear surfaces. Besides, the studied results demonstrate that the intensity of coherent absorption and the position of absorption peaks can be adapted by altering the magnetic field and the thicknesses of ferrite layers. It follows that the absorption peaks can cover most frequency points from 58.6 to 65.9 THz via changing the thicknesses of the external magnetic field and ferrite layers. Moreover, the structure also has the potential for wide-angle absorption. This research furnishes a significant reference for the design of the multi-frequency absorption optoelectronic device and phase sensor.
Investigation of the microstructure of TC1/1060/6061 explosive composites based on experiments and numerical simulations
Authors: Yuan Jiaxin , Shao Fei , Bai Linyue , Zhang Hongwei , Xu Qian , Gao Lei , Ma Qingna
Published: April 2022

In this study, the microstructure of TC1/1060/6061 composites manufactured by explosive welding was investigated using experiments and numerical simulations. The results showed that the two interfaces of the TC1/1060/6061 composites exhibited an overall linear bonding interface without defects such as macroscopic cracks or pores. A melting layer caused by the adiabatic compression of air was observed, and the overall welding quality of the composites was good. There were no intermetallic compounds observed at the TC1/1060 interface, and the diffusion area was short, which formed a metallurgical bond. After heat treatment, the grains on the base plate and interlayer side of the composites formed a cubic recrystallized texture, while the grains on the flyer plate side developed a fine-grained structure. The microhardness of the base plate and flyer plate was higher closer to the interface due to the process hardening effect, while the microhardness of the interlayer remained stable. The formation process of these two interfaces was analyzed by numerical simulations, and jetting was observed at the 1060/6061 interface. The TC1/1060 interface in the numerical simulations showed a linear morphology, and the 1060/6061 interface showed a microwave morphology.
A type of parabolic flow with mixed hessians on compact Kähler manifolds
Authors: Tsai Yi-Lin
Published: April 2022

We investigate the solvability of a general class of mixed Hessian type equations on compact Kähler manifolds. Based on an observation in Guan and Zhang [Pure Appl. Math. Q. 17 (2021), pp. 865–907], the mixed Hessian equations can be rewritten as elliptic and concave equations which satisfy the general framework in Székelyhidi [J. Differential Geom. 109 (2018), pp. 337–378] and Phong and Tô [Ann. Sci. Éc. Norm. Supér. (4) 54 (2021), pp. 793–829] except one condition. We notice that the absence of this condition can be overcome by using the particular structure of the mixed Hessian equations. As an application, the solvability of the deformed Hermitian Yang-Mills equations in dimension three was also studied.
Triviality of the 𝐽₄-equivalence among homology 3-spheres
Authors: Faes Quentin
Published: April 2022

We prove that all homology 3-spheres are

J
4

J_4

-equivalent, i.e. that any homology 3-sphere can be obtained from one another by twisting one of its Heegaard splittings by an element of the mapping class group acting trivially on the fourth nilpotent quotient of the fundamental group of the gluing surface. We do so by exhibiting an element of

J
4

J_4

, the fourth term of the Johnson filtration of the mapping class group, on which (the core of) the Casson invariant takes the value

1
1

. In particular, this provides an explicit example of an element of

J
4

J_4

that is not a commutator of length

2
2

in the Torelli group.
Polyploidy on islands – concerted evolution and gene loss amid chromosomal stasis
Authors: Joshi Prashant , Ansari Helal , Dickson Rowan , Ellison Nicholas W , Skema Cynthia , Tate Jennifer A
Published: April 2022

Background and Aims

Polyploidy is an important process that often generates genomic diversity within lineages, but it can also cause changes that result in loss of genomic material. Island lineages, while often polyploid, typically show chromosomal stasis but have not been investigated in detail regarding smaller-scale gene loss. Our aim was to investigate post-polyploidization genome dynamics in a chromosomally stable lineage of Malvaceae endemic to New Zealand.

Methods

We determined chromosome numbers and used fluorescence in situ hybridization to localize 18S and 5S rDNA. Gene sequencing of 18S rDNA, the internal transcribed spacers (ITS) with intervening 5.8S rDNA, and a low-copy nuclear gene, GBSSI-1, was undertaken to determine if gene loss occurred in the New Zealand lineage following polyploidy.

Key Results

The chromosome number for all species investigated was 2n = 42, with the first published report for the monotypic Australian genus Asterotrichion. The five species investigated all had two 5S rDNA signals localized interstitially on the long arm of one of the largest chromosome pairs. All species, except Plagianthus regius, had two 18S rDNA signals localized proximally on the short arm of one of the smallest chromosome pairs. Plagianthus regius had two additional 18S rDNA signals on a separate chromosome, giving a total of four. Sequencing of nuclear ribosomal 18S rDNA and the ITS cistron indicated loss of historical ribosomal repeats. Phylogenetic analysis of a low-copy nuclear gene, GBSSI-1, indicated that some lineages maintained three copies of the locus, while others have lost one or two copies.

Conclusions

Although island endemic lineages show chromosomal stasis, with no additional changes in chromosome number, they may undergo smaller-scale processes of gene loss and concerted evolution ultimately leading to further genome restructuring and downsizing.
Exploiting deep transfer learning for the prediction of functional non-coding variants using genomic sequence
Authors: Chen Li , Wang Ye , Zhao Fengdi
Published: April 2022

Motivation

Though genome-wide association studies have identified tens of thousands of variants associated with complex traits and most of them fall within the non-coding regions, they may not be the causal ones. The development of high-throughput functional assays leads to the discovery of experimental validated non-coding functional variants. However, these validated variants are rare due to technical difficulty and financial cost. The small sample size of validated variants makes it less reliable to develop a supervised machine learning model for achieving a whole genome-wide prediction of non-coding causal variants.

Results

We will exploit a deep transfer learning model, which is based on convolutional neural network, to improve the prediction for functional non-coding variants (NCVs). To address the challenge of small sample size, the transfer learning model leverages both large-scale generic functional NCVs to improve the learning of low-level features and context-specific functional NCVs to learn high-level features toward the context-specific prediction task. By evaluating the deep transfer learning model on three MPRA datasets and 16 GWAS datasets, we demonstrate that the proposed model outperforms deep learning models without pretraining or retraining. In addition, the deep transfer learning model outperforms 18 existing computational methods in both MPRA and GWAS datasets.

Availability and implementation

https://github.com/lichen-lab/TLVar.

Supplementary information

Supplementary data are available at Bioinformatics online.
Half a century of haemodialysis: two patient journeys
Authors: Pavlovic Drasko , Salehi Tania , Piccoli Giorgina B , Coates Patrick T
Published: April 2022

The history of renal replacement therapy (RRT) for end-stage kidney disease (ESKD) started in 1960 and has reached, in these six decades, goals initially unforeseen. This report describes two patients who commenced dialysis at the age of 17 and 27, for 53 and 45 years, respectively, whereby the modality of RRT was mostly in the form of home haemodialysis. The history of these two patients, who started RRT in distant parts of the world, Australia and Croatia, highlights not only the advances made over time, to significantly delay the onset and reduce the morbidity and mortality associated with ESKD, but also underlines the importance of empowerment and commitment, added values in home haemodialysis.
CRISPR and cardiovascular diseases
Authors: Musunuru Kiran
Published: April 2022

CRISPR technologies have progressed by leaps and bounds over the past decade, not only having a transformative effect on biomedical research but also yielding new therapies that are poised to enter the clinic. In this review, I give an overview of (i) the various CRISPR DNA-editing technologies, including standard nuclease gene editing, base editing, prime editing, and epigenome editing, (ii) their impact on cardiovascular basic science research, including animal models, human pluripotent stem cell models, and functional screens, and (iii) emerging therapeutic applications for patients with cardiovascular diseases, focusing on the examples of hypercholesterolaemia, transthyretin amyloidosis, and Duchenne muscular dystrophy.
Cellular interplay between cardiomyocytes and non-myocytes in diabetic cardiomyopathy
Authors: Phang Ren Jie , Ritchie Rebecca H , Hausenloy Derek J , Lees Jarmon G , Lim Shiang Y
Published: April 2022

Patients with Type 2 diabetes mellitus (T2DM) frequently exhibit a distinctive cardiac phenotype known as diabetic cardiomyopathy. Cardiac complications associated with T2DM include cardiac inflammation, hypertrophy, fibrosis, and diastolic dysfunction in the early stages of the disease, which can progress to systolic dysfunction and heart failure. Effective therapeutic options for diabetic cardiomyopathy are limited and often have conflicting results. The lack of effective treatments for diabetic cardiomyopathy is due in part, to our poor understanding of the disease development and progression, as well as a lack of robust and valid preclinical human models that can accurately recapitulate the pathophysiology of the human heart. In addition to cardiomyocytes, the heart contains a heterogeneous population of non-myocytes including fibroblasts, vascular cells, autonomic neurons, and immune cells. These cardiac non-myocytes play important roles in cardiac homeostasis and disease, yet the effect of hyperglycaemia and hyperlipidaemia on these cell types is often overlooked in preclinical models of diabetic cardiomyopathy. The advent of human-induced pluripotent stem cells provides a new paradigm in which to model diabetic cardiomyopathy as they can be differentiated into all cell types in the human heart. This review will discuss the roles of cardiac non-myocytes and their dynamic intercellular interactions in the pathogenesis of diabetic cardiomyopathy. We will also discuss the use of sodium-glucose cotransporter 2 inhibitors as a therapy for diabetic cardiomyopathy and their known impacts on non-myocytes. These developments will no doubt facilitate the discovery of novel treatment targets for preventing the onset and progression of diabetic cardiomyopathy.
The Long-Term Distributional and Welfare Effects of Covid-19 School Closures
Authors: Fuchs-Schündeln Nicola , Krueger Dirk , Ludwig Alexander , Popova Irina
Published: April 2022

Using a structural life-cycle model, we quantify the heterogeneous impact of school closures during the corona crisis on children affected at different ages and coming from households with different parental characteristics. In the model, public investment through schooling is combined with parental time and resource investments in the production of child human capital at different stages in the children’s development process. We quantitatively characterise the long-term consequences from a COVID-19-induced loss of schooling, and find average losses in the present discounted value of lifetime earnings of the affected children of $2.1\%$, as well as welfare losses equivalent to about $1.2\%$ of permanent consumption. Because of self-productivity in the human capital production function, younger children are hurt more by the school closures than older children. The negative impact of the crisis on children’s welfare is especially severe for those with parents with low educational attainment and low assets.
A framework for educating and empowering students by teaching about history and consequences of bias in STEM
Authors: Moreau Corrie S , Darby Andrea M , Demery Amelia-Juliette C , Arcila Hernández Lina M , Meaders Clara L
Published: April 2022

Racism and bias are pervasive in society—and science, technology, engineering, and mathematics (STEM) fields are not immune to these issues. It is imperative that we educate ourselves and our students about the history and consequences of this bias in STEM, investigate the research showing bias toward marginalized groups, understand how to interpret misuses of science in perpetuating bias, and identify advances and solutions to overcome racism and bias throughout our professional and personal lives. Here, we present one model for teaching a universal course for participants of all professional stages to address these issues and initiate solutions. As very few institutions require students to enroll in courses on racism and bias in STEM or even offer such courses, our curriculum could be used as a blueprint for implementation across institutions. Ultimately, institutions and academic disciplines can incorporate this important material with more region and/or discipline specific studies of bias.
Expression and structure of the Chlamydia trachomatis DksA ortholog
Authors: Mandel Cameron , Yang Hong , Buchko Garry W , Abendroth Jan , Grieshaber Nicole , Chiarelli Travis , Grieshaber Scott , Omsland Anders
Published: April 2022

Chlamydia trachomatis is a bacterial obligate intracellular parasite and a significant cause of human disease, including sexually transmitted infections and trachoma. The bacterial RNA polymerase-binding protein DksA is a transcription factor integral to the multicomponent bacterial stress response pathway known as the stringent response. The genome of C. trachomatis encodes a DksA ortholog (DksACt) that is maximally expressed at 15–20 h post infection, a time frame correlating with the onset of transition between the replicative reticulate body (RB) and infectious elementary body (EB) forms of the pathogen. Ectopic overexpression of DksACt in C. trachomatis prior to RB–EB transitions during infection of HeLa cells resulted in a 39.3% reduction in overall replication (yield) and a 49.6% reduction in recovered EBs. While the overall domain organization of DksACt is similar to the DksA ortholog of Escherichia coli (DksAEc), DksACt did not functionally complement DksAEc. Transcription of dksACt is regulated by tandem promoters, one of which also controls expression of nrdR, encoding a negative regulator of deoxyribonucleotide biosynthesis. The phenotype resulting from ectopic expression of DksACt and the correlation between dksACt and nrdR expression is consistent with a role for DksACt in the C. trachomatis developmental cycle.
Phosphorylation of HORMA-domain protein HTP-3 at Serine 285 is dispensable for crossover formation
Authors: Das Debabrata , Trivedi Shalini , Blazícková Jitka , Arur Swathi , Silva Nicola
Published: April 2022

Generation of functional gametes is accomplished through a multilayered and finely orchestrated succession of events during meiotic progression. In the Caenorhabditis elegans germline, the HORMA-domain-containing protein HTP-3 plays pivotal roles for the establishment of chromosome axes and the efficient induction of programmed DNA double-strand breaks, both of which are crucial for crossover formation. Double-strand breaks allow for accurate chromosome segregation during the first meiotic division and therefore are an essential requirement for the production of healthy gametes. Phosphorylation-dependent regulation of HORMAD protein plays important roles in controlling meiotic chromosome behavior. Here, we document a phospho-site in HTP-3 at Serine 285 that is constitutively phosphorylated during meiotic prophase I. pHTP-3S285 localization overlaps with panHTP-3 except in nuclei undergoing physiological apoptosis, in which pHTP-3 is absent. Surprisingly, we observed that phosphorylation of HTP-3 at S285 is independent of the canonical kinases that control meiotic progression in nematodes. During meiosis, the htp-3(S285A) mutant displays accelerated RAD-51 turnover, but no other meiotic abnormalities. Altogether, these data indicate that the Ser285 phosphorylation is independent of canonical meiotic protein kinases and does not regulate HTP-3-dependent meiotic processes. We propose a model wherein phosphorylation of HTP-3 occurs through noncanonical or redundant meiotic kinases and/or is likely redundant with additional phospho-sites for function in vivo.
Large-scale focusing joint inversion of gravity and magnetic data with Gramian constraint
Authors: Vatankhah Saeed , Renaut Rosemary A , Huang Xingguo , Mickus Kevin , Gharloghi Mostafa
Published: April 2022

A fast algorithm for the large-scale joint inversion of gravity and magnetic data is developed. The algorithm uses a non-linear Gramian constraint to impose correlation between the density and susceptibility of the reconstructed models. The global objective function is formulated in the space of the weighted parameters, but the Gramian constraint is implemented in the original space, and the non-linear constraint is imposed using two separate Lagrange parameters, one for each model domain. It is significant that this combined approach, using the two spaces provides more similarity between the reconstructed models. Moreover, it is shown theoretically that the gradient for the use of the unweighted space is not a scalar multiple of that used for the weighted space, and hence cannot be accounted for by adjusting the Lagrange parameters. It is assumed that the measured data are obtained on a uniform grid and that a consistent regular discretization of the volume domain is imposed. Then, the sensitivity matrices exhibit a block-Toeplitz-Toeplitz-block structure for each depth layer of the model domain, and both forward and transpose operations with the matrices can be implemented efficiently using two dimensional fast Fourier transforms. This makes it feasible to solve for large scale problems with respect to both computational costs and memory demands, and to solve the non-linear problem by applying iterative methods that rely only on matrix–vector multiplications. As such, the use of the regularized reweighted conjugate gradient algorithm, in conjunction with the structure of the sensitivity matrices, leads to a fast methodology for large-scale joint inversion of geophysical data sets. Numerical simulations demonstrate that it is possible to apply a non-linear joint inversion algorithm, with Lp-norm stabilisers, for the reconstruction of large model domains on a standard laptop computer. It is demonstrated, that while the p = 1 choice provides sparse reconstructed solutions with sharp boundaries, it is also possible to use p = 2 in order to provide smooth and blurred models. The methodology is used for inverting gravity and magnetic data obtained over an area in northwest of Mesoproterozoic St Francois Terrane, southeast of Missouri, USA.