bluuebunny/crossref_metadata_2025 huggingface dataset:
A capacitive displacement system for studying the piezoelectric strain and its temperature variation
Authors: Fu Desheng , Kakihara Eiki
Published: April 2021

A capacitive displacement system was constructed to measure the electric-field-induced piezoelectric strain in the simple form of either a bulk or thin film. The system can determine an AC displacement of 2 pm precisely by using a lock-in detection and can measure the large displacement within the range of ±25μm with a sub-nanometer resolution. The system can also be used to measure the variation in strain within the temperature range of 210–450 K, allowing the evaluation of the temperature coefficient of a piezoelectric constant and the studies on the effects of a phase transition on the piezoelectric response. Experimental results on quartz, Pb(Zr1−xTix)TiO3 ceramics and thin films, and BaTiO3 confirm the capabilities of the developed system.
Nano-confinement effects on liquid pressure
Authors: Zou An , Maroo Shalabh C.
Published: April 2021

In this study, molecular dynamics simulations are performed to estimate the equilibrium pressure of liquid confined in nanopores. The simulations show that pressure is highly sensitive to the pore size and can significantly change from absolute positive to absolute negative values for a very small (0.1 nm) change in the pore size. The contribution from the solid–liquid interaction always dominates the pressure in the first liquid layer adjacent to the surface and the sensitiveness of pressure on the pore size is dependent on the atom distribution in the liquid layers. A surface influence number S is introduced to quantitatively characterize the degree of the confinement. At constant system temperature, the S number decreases with increasing pore size based on a power-law function. In nanopores with large S number, the pore liquid pressure is found to be independent of bulk liquid pressure, whereas in nanopores with small S number, the pore pressure is dependent and increases with bulk pressure.
Airfoil flow receptivity to simulated tonal noise emissions
Authors: Pröbsting S. , Yarusevych S.
Published: April 2021

On airfoils at low to moderate Reynolds numbers, trailing edge sound can have a feedback effect on the development of instability waves resulting in strongly periodic vortex shedding and tonal noise. This complex problem is decoupled in this study to investigate the flow response to deterministic noise emissions. The flow receptivity and response to tonal noise are examined using controlled steady and transient acoustic excitation. Experiments are performed on a NACA 0018 airfoil at a Reynolds number of 1.15×105 and an angle of attack of 5°, with a separation bubble on the suction side. Controlled acoustic perturbations are introduced via a loudspeaker. A combination of mean and time-resolved surface pressure and simultaneous high-speed particle image velocimetry measurements provides insight into the response of the bubble to simulated acoustic forcing. Amplification of shear layer perturbations in the fore portion of the separation bubble is observed only after some time delay from the onset of acoustic forcing. This places the receptivity region within the boundary layer upstream of the separation bubble, extending from the leading edge to just downstream of the suction peak. The acoustically excited perturbations in the receptivity region attain higher amplitudes than natural disturbances and are amplified significantly in the separation bubble, leading to a transient reduction in the separation bubble size. Results elucidate the ensuing transient response of the separation bubble, illustrating the flow dynamics expected during the initiation of the acoustic feedback loop during natural tonal noise emissions on an airfoil.
Single-nanowire silicon photodetectors with core-shell radial Schottky junction for self-powering application
Authors: Guan Yuxiang , Cao Guoyang , Li Xiaofeng
Published: April 2021

A silicon (Si) based core-shell single-nanowire photodetector with the radially configured Schottky junction is presented for high-performance self-powering photodetection application. The optoelectronic properties of the device are evaluated by performing a comprehensive device-level simulation using the finite-element method. An extremely high responsivity of 107 A/W at zero bias is predicted, which is three orders higher than that of the axially configured device. Additionally, the time-dependent simulation reveals that the system with the radial semiconductor junction shows a fast response with an unbiased response time of 22 μs. We explore detailedly the underlying mechanisms for the high-performance responses of this nanostructured photodetector. It is found that the single-nanowire design with the radial junction enables a high light absorption in optical domain as well as a very efficient and fast carrier transport in electrical domain.
Origin of negative anomalous Nernst thermopower in Mn-Ga ordered alloys
Authors: Zhou Weinan , Masuda Keisuke , Sakuraba Yuya
Published: April 2021

The negative sign of the anomalous Nernst thermopower (SANE) observed in Mn-Ga ordered alloys is an attractive property for thermoelectric applications exploiting the anomalous Nernst effect (ANE); however, its origin has not been clarified. In this study, to gain insight into the negative SANE, we prepared epitaxial thin films of MnxGa100−x with x ranging from 56.2 to 71.7 and systematically investigated the structural, magnetic, and transport properties, including the anomalous Hall effect (AHE) and the ANE. The measured SANE is negative for all samples and shows close to one order of magnitude difference among different compositions. Together with the measured transport properties, we were able to separate the two different contributions of the ANE, i.e., one originating from the transverse thermoelectric coefficient (αxy) and the other one originating from the AHE acting on the longitudinal carrier flow induced by the Seebeck effect. Both contributions are found to be negative for all samples, while the experimentally obtained negative αxy exhibits a monotonic increase toward zero with increasing x, which is consistent with the tendency indicated by first-principle calculations. Our results show that the large difference in the negative SANE is mostly attributed to αxy, and thus shed light on further enhancement of the ANE in Mn-based ordered alloys.
An active x-ray beamstop based on single crystal CVD diamond at beamline SWING
Authors: Desjardins K. , Pomorski M. , Bizien T. , Thureau A. , Menneglier C. , Pérez J.
Published: April 2021

A compact active x-ray beamstop has been developed for the SWING beamline at Synchrotron SOLEIL with two main functions, blocking the x-ray beam directly transmitted by the sample to protect the Dectris EigerX4M 2D detector and monitoring its intensity. The beamstop is composed of a sensor inserted in a well of tungsten carbide. The sensor is based on a piece of free-standing single crystal chemical vapor deposited diamond used in the ionization chamber mode. The beamstop has been installed on the beamline detector stage within the detection vacuum chamber, just upstream of the large 2D detector. The intensity monitoring performance (rms noise over signal) is shown to be better than 0.06% and the linearity is shown to be better than 2% for over more than five decades. The beamstop has been calibrated between 5 and 16 keV to provide the photon flux measurements in absolute units (ph/s). The specific design of the beamstop increases the small-angle x-ray scattering q-range by a factor of 1.5 in the low angle side, as compared to the previous active beamstop, based on a more standard commercial Si diode. The beamstop has been available for three years for SWING user operation (5–17 keV). It is fully compatible with the different beamline operating modes and fluxes, except in the microbeam mode, where the very divergent beam becomes too large at the beamstop position, and the previous, larger, beamstop is then more appropriate.
Substrate-controlled dynamics of spin qubits in low dimensional van der Waals materials
Authors: Onizhuk Mykyta , Galli Giulia
Published: April 2021

We report a theoretical study of the coherence dynamics of spin qubits in two-dimensional materials (2DMs) and van der Waals heterostructures, as a function of the host thickness and the composition of the surrounding environment. We focus on MoS2 and WS2, two promising systems for quantum technology applications, and we consider the decoherence arising from the interaction of the spin qubit with nuclear spins. We show that the Hahn-echo coherence time is determined by a complex interplay between the source of decoherence in the qubit host and in the environment, which in turn determines whether the noise evolution is in a classical or quantum mechanical regime. We suggest that the composition and thickness of van der Waals heterostructures encapsulating a qubit host can be engineered to maximize coherence times. Finally, we discuss how quantum sensors may be able to probe the dynamics of the nuclear bath in 2DMs.
In vivo anatomical imaging of colorectum by tens-of-micron-resolved photoacoustic/ultrasonic endoscope
Authors: Guo Ting , Xiong Kedi , Zhang Zixin , Li Ling , Yang Sihua
Published: April 2021

The existing photoacoustic/ultrasound (PA/US) endoscopes with compromise in lateral resolution were difficult to realize superior anatomical imaging. To obtain comprehensive biological information of the colorectum in a noninvasive manner, a tens-of-micron-resolved PA/US endoscope with a 360° field of view was developed. A coaxial structure, which ensures optical and acoustic foci aligned, was employed, and a PVDF-based focused transducer with a high frequency was applied. The endoscopic system achieved lateral resolutions of 16 μm (PA) and 73 μm (US), and axial resolution of 65 μm. Phantom and ex vivo experiments were performed to estimate the performance of the dual-modality endoscope. In vivo three-dimensional imaging of rabbit colorectum exhibited the intact vascular network at different depths from the mucosa of the colorectal wall to the mesentery, and the structures beneath them. Therefore, in vivo anatomical imaging demonstrates that the tens-of-micron-resolved PA/US endoscope holds great potential in the clinical detection of colorectal diseases.
Dynamical formulation of low-energy scattering in one dimension
Authors: Loran Farhang , Mostafazadeh Ali
Published: April 2021

The transfer matrix M of a short-range potential may be expressed in terms of the time-evolution operator for an effective two-level quantum system with a time-dependent non-Hermitian Hamiltonian. This leads to a dynamical formulation of stationary scattering. We explore the utility of this formulation in the study of the low-energy behavior of the scattering data. In particular, for the exponentially decaying potentials, we devise a simple iterative scheme for computing terms of arbitrary order in the series expansion of M in powers of the wavenumber. The coefficients of this series are determined in terms of a pair of solutions of the zero-energy stationary Schrödinger equation. We introduce a transfer matrix for the latter equation, express it in terms of the time-evolution operator for an effective two-level quantum system, and use it to obtain a perturbative series expansion for the solutions of the zero-energy stationary Schrödinger equation. Our approach allows for identifying the zero-energy resonances for scattering potentials in both full line and half-line with zeros of the entries of the zero-energy transfer matrix of the potential or its trivial extension to the full line.
Sexually transmissible infections and sexual risk behaviour among deployed, ship-assigned USA Navy and Marine Corps personnel
Authors: Triplett Daniel P. , Harbertson Judith , Hale Braden
Published: April 2021

Background Data show sexually transmissible infection (STI) diagnoses in USA military personnel engaging in unprotected sex are higher during deployment than before or after. We examined sexual risk behaviour, same-sex contact, mixed sex partnerships (both casual and committed partners) and STIs among ship-assigned USA Navy and Marine Corps personnel to assess increased risk. Methods: Data on sexual risk behaviour, partner type, gender, and healthcare provider-diagnosed STIs were collected longitudinally (2012–14) among sexually active personnel during deployment. Descriptive and bivariate data stratified by sex, STIs, and partner types were analysed using χ2 and t-tests, with statistical significance defined as P < 0.05. Results: The final sample (n = 634) included 452 men (71%) and 182 women (29%). STI prevalence among males was 8% (n = 36); men who have sex with men (MSM) accounted for 25% of total STIs, and 43% of MSM reported an STI. Among all reporting STIs, 29% reported occasional partners, service member partners (15%) and non-condom use (16%). The highest proportions of non-condom use (71%), alcohol before sex (82%), and same-sex partners (67%) were reported by participants with mixed sex partners; 69% of these reported service member partners. Conclusions: Personnel with mixed partners reported high proportions of sexual risk behaviour. MSM accounted for 9% of the total population, but 25% of all STIs. As the majority of those with mixed partners and MSM also reported service member sex partners, safer sex education and prompt STI identification/treatment among these groups could reduce STI transmission among military personnel.
How to build a firebreak to stop smouldering peat fire: insights from a laboratory-scale study
Authors: Lin Shaorun , Liu Yanhui , Huang Xinyan
Published: April 2021

Smouldering wildfire is an important disturbance to peatlands worldwide; it contributes significantly to global carbon emissions and provides positive feedback to climate change. Herein, we explore the feasibility of firebreaks to control smouldering peat fires through laboratory-scale experiments. The dry-mass moisture content (MC) of peat soil was varied from 10% (air-dried) to 125%. We found that smouldering peat fire may be successfully extinguished above the mineral soil layer, even if the peat layer is not entirely removed. There are two criteria for an effective peat firebreak: (I) adding water to make the peat layer sufficiently wet (>115% MC in the present work); and (II) ensuring that the peat layer is thinner than the quenching thickness (< 5 cm). Criterion I may fail if the water table declines or the peat layer is dried by surface fires and hot weather; thus, satisfying Criterion II is more attainable. A sloping trench-shaped firebreak is recommended to guide water flow and help maintain high peat moisture content. This work provides a scientific foundation for fighting and mitigating smouldering wildfires and provides guidance about protective measures for field-scale peat fire experiments.
The impact of identity by descent on fitness and disease in dogs
Authors: Mooney Jazlyn A. , Yohannes Abigail , Lohmueller Kirk E.
Published: April 2021

Significance

Dogs and humans have coexisted together for thousands of years, but it was not until the Victorian Era that humans practiced selective breeding to produce the modern standards we see today. Strong artificial selection during the breed formation period has simplified the genetic architecture of complex traits and caused an enrichment of identity-by-descent (IBD) segments in the dog genome. This study demonstrates the value of IBD segments and utilizes them to infer the recent demography of canids, predict case-control status for complex traits, locate regions of the genome potentially linked to inbreeding depression, and to identify understudied breeds where there is potential to discover new disease-associated variants.
Mycobacterial fatty acid catabolism is repressed by FdmR to sustain lipogenesis and virulence
Authors: Dong Wenyue , Nie Xiaoqun , Zhu Hong , Liu Qingyun , Shi Kunxiong , You Linlin , Zhang Yu , Fan Hongyan , Yan Bo , Niu Chen , Lyu Liang-Dong , Zhao Guo-Ping , Yang Chen
Published: April 2021

Significance

An improved understanding of fatty acid metabolism in pathogenic mycobacteria is critical for development of new chemotherapeutics. Here, we identified FdmR, a previously uncharacterized transcriptional factor, as the key regulator of fatty acid catabolism in the pathogen
Mycobacterium marinum
. We demonstrated that FdmR optimizes fatty acid utilization and allows for a high rate of cell growth with modest consumption of the nutrients. Moreover, we found that FdmR suppresses degradation of de novo-synthesized fatty acids and controls the size and abundance of virulence-associated lipids and mycolates. These results reveal that FdmR-mediated regulation serves important functions in mycobacterial physiology and pathogenicity. Thus, this study identifies FdmR as a potentially attractive target for novel therapeutic intervention.
Learning effective physical laws for generating cosmological hydrodynamics with Lagrangian deep learning
Authors: Dai Biwei , Seljak Uroš
Published: April 2021

Significance

Hydrodynamical simulations are crucial for accurately predicting cosmological observations, but they are computationally too expensive to simulate in a full survey volume. Gravity-only N-body simulations reduce the computational cost but cannot directly model the observables such as stars and gas. Here we propose a deep-learning approach to generate these observables. The model consists of several layers of Lagrangian displacement field moving the particles. It requires only a handful of parameters to learn, in contrast to neural networks, and can be viewed as learning the effective physical laws. By combining N-body solvers with our model, we are able to generate higher-accuracy hydrodynamic observables with computational costs several orders of magnitude cheaper than the traditional hydrodynamical simulations at the same resolution.
Microbiome reduction and endosymbiont gain from a switch in sea urchin life history
Authors: Carrier Tyler J. , Leigh Brittany A. , Deaker Dione J. , Devens Hannah R. , Wray Gregory A. , Bordenstein Seth R. , Byrne Maria , Reitzel Adam M.
Published: April 2021

Significance

Microbes have a strong impact on the biology of their host, with those living in the gut being essential to immunity, development, and metabolism. A functional gut, however, has been lost several times during animal evolution. Here, using sister sea urchin species, we report that the loss of a functional gut corresponds with a reduced microbial diversity and abundance. Gut loss also coincides with associating with an endosymbiont that complements host nutrition and potentially impacts host reproduction. Therefore, transitions in developmental life histories in animals can accompany shifts in the microbial community.
Biomechanical trade-offs in the pelvic floor constrain the evolution of the human birth canal
Authors: Stansfield Ekaterina , Kumar Krishna , Mitteroecker Philipp , Grunstra Nicole D. S.
Published: April 2021

Significance

The relatively small human birth canal has arisen from an evolutionary trade-off between multiple antagonistic selective forces. We present evidence that a large pelvic floor is disadvantageous for maintaining continence and supporting the weight of the inner organs and the fetus through multiple finite element analyses of pelvic floor models varying in size and thickness. An increase in pelvic floor size led to a disproportionately large deflection as well as higher tissue stretches and stresses. Increased pelvic floor thickness considerably reduced deflection by increasing stiffness. However, as a side effect, it increases the intra-abdominal pressure necessary for childbirth, thus reflecting another evolutionary trade-off affecting not only the size but also the thickness of the pelvic floor.
Impaired TRPV4-eNOS signaling in trabecular meshwork elevates intraocular pressure in glaucoma
Authors: Patel Pinkal D. , Chen Yen-Lin , Kasetti Ramesh B. , Maddineni Prabhavathi , Mayhew William , Millar J. Cameron , Ellis Dorette Z. , Sonkusare Swapnil K. , Zode Gulab S.
Published: April 2021

Significance

Primary Open Angle Glaucoma (POAG) is the most common form of glaucoma that leads to irreversible vision loss and blindness worldwide. POAG is often associated with elevated intraocular pressure (IOP). The trabecular meshwork (TM), a molecular sieve-like structure, tightly controls IOP by constantly adjusting the resistance to aqueous humor (AH) outflow. In POAG, there is increased resistance to AH outflow, elevating IOP. Here, we show that mechanically activated TRPV4 channels in TM play a critical role in IOP regulation via calcium-mediated activation of eNOS signaling and production of nitric oxide (NO). Importantly, we show that impaired TRPV4 channel activity results in reduced NO bioavailability and elevated IOP in glaucoma. Our findings support impaired TRPV4-eNOS signaling to the pathogenesis of POAG.
Orphan nuclear receptor ERR-γ regulates hepatic FGF23 production in acute kidney injury
Authors: Radhakrishnan Kamalakannan , Kim Yong-Hoon , Jung Yoon Seok , Kim Don-Kyu , Na Soon-Young , Lim Daejin , Kim Dong Hun , Kim Jina , Kim Hyung-Seok , Choy Hyon E. , Cho Sung Jin , Lee In-Kyu , Ayvaz Şamil , Nittka Stefanie , Fliser Danilo , Schunk Stefan J. , Speer Thimoteus , Dooley Steven , Lee Chul-Ho , Choi Hueng-Sik
Published: April 2021

Significance

Bone is the main source of fibroblast growth factor 23 (FGF23), which is important for phosphate and vitamin D homeostasis. In acute kidney injury (AKI), high blood levels of FGF23 are positively correlated with disease progression and increased risk of mortality. Reducing adverse plasma FGF23 levels in AKI patients is favorable. We showed here that hepatocytes are the major source of circulating FGF23, and orphan nuclear receptor ERR-γ is a novel transcriptional regulator of hepatic FGF23 production in AKI. Liver-specific depletion of ERR-γ or ERR-γ inverse agonist, GSK5182, significantly reduced plasma levels of FGF23 in AKI. This study reveals liver is the source of FGF23 and a therapeutic strategy to control pathologically adverse plasma FGF23 levels in AKI.
Discriminating symbiosis and immunity signals by receptor competition in rice
Authors: Zhang Chi , He Jiangman , Dai Huiling , Wang Gang , Zhang Xiaowei , Wang Chao , Shi Jincai , Chen Xi , Wang Dapeng , Wang Ertao
Published: April 2021

Significance

Plant adaptation in nature relies on the appropriate response to symbiotic and pathogenic microbes. Chitin is an important component of the mycorrhizal fungi cell wall and a major microbe-associated molecular pattern (MAMP), which can activate pattern recognition receptors and trigger plant immunity. How MAMP-triggered immunity is suppressed by symbiotic fungi to establish symbiosis remains elusive. Here, we found that the CO4 (Chitotetraose) symbiotic receptor OsMYR1 cannot only initiate symbiotic signaling but also can repress rice immunity by depleting the receptor-like kinase OsCERK1, thereby preventing the formation of the immunity complex OsCERK1–OsCEBiP. We propose that receptor competition for OsCERK1 in rice underlies a switch that discerns defense and symbiotic signals.
Cryo-EM structure of
Mycobacterium smegmatis
DyP-loaded encapsulin
Authors: Tang Yanting , Mu An , Zhang Yuying , Zhou Shan , Wang Weiwei , Lai Yuezheng , Zhou Xiaoting , Liu Fengjiang , Yang Xiuna , Gong Hongri , Wang Quan , Rao Zihe
Published: April 2021

Significance

Tuberculosis, caused by
Mycobacterium tuberculosis
, remains a major global public health problem. Deciphering the complex biology of
M. tuberculosis
will aid in the development of new therapeutics to combat this pathogen. Encapsulins, naturally encapsulating specific cargo proteins, are a recently discovered class of smaller proteinaceous compartments found in bacteria and archaea and needed for essential physiological processes. Here, we report the structural and mechanistic characterization of a native DyP-packaging encapsulin from the
Mycobacterium smegmatis
, a model system for
M. tuberculosis
. Our results contribute to the understanding of the assembly and physiological role of the encapsulin systems and provide a rational framework for antituberculosis drug design.
Gymnosporangium yamadae (Japanese apple rust).
Authors:   USA, USDA-ARS
Published: April 2021

G. yamadae belongs to the Uredinales, which includes the rust fungi, all of which cause diseases on plants. At present, G. yamadae, which is a serious pathogen of domestic apples [Malus domestica], has limited distribution.
Lymantria dispar (gypsy moth).
Authors: Tobin Patrick
Published: April 2021

The gypsy moth is likely to ultimately occupy virtually all portions of the temperate world where oaks and other suitable host plants occur. Consequently, the northern hemisphere is more at risk for establishment than the southern hemisphere though some suitable hosts do occur in these areas. The gypsy moth is apparently not able to persist in very cold (e.g. Finland) or warm (subtropical to tropical) regions. The gypsy moth is a 'proven' invader. The broad range of host plants that it utilizes (Liebhold et al. 1995), along with its high reproductive rate combine to make this insect a very successful invader of many types of forest and urban landscapes. Another characteristic that contributes to the gypsy moth's invasiveness is its propensity to be transported on human-made objects (e.g., egg masses can be laid on vehicles, logs, etc.). Perhaps the greatest limitation this species has as an invader is that females (of the European strain) are incapable of flight and this limits its rate of unassisted range expansion. However, as females of the Asian strain are capable of flight and all strains can lay their eggs on human-made objects, established populations are nevertheless able to spread.
Codiaeum variegatum (garden croton).
Authors: Ventosa-Febles Eduardo A. , Cordero-Ramos Nicole
Published: April 2021

A datasheet on Codiaeum variegatum covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Cissus quadrangularis (treebine).
Authors: Rojas-Sandoval Julissa
Published: April 2021

A datasheet on Cissus quadrangularis covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Ficus microcarpa (Indian Laurel tree).
Authors: Datiles Marianne Jennifer , Acevedo-Rodríguez Pedro
Published: April 2021

A datasheet on Ficus microcarpa covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Atriplex semibaccata (Australian saltbush).
Authors: Pasiecznik Nick
Published: April 2021

A datasheet on Atriplex semibaccata covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Averrhoa bilimbi (bilimbi).
Authors: Datiles Marianne Jennifer
Published: April 2021

A datasheet on Averrhoa bilimbi covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
GRASPing for consensus about the Golgi apparatus
Authors: Burd Christopher G.
Published: April 2021

Cisternae of the Golgi apparatus adhere to each other to form stacks, which are aligned side by side to form the Golgi ribbon. Two proteins, GRASP65 and GRASP55, previously implicated in stacking of cisternae, are shown to be required for the formation of the Golgi ribbon.
Contraction–relaxation coupling is unaltered by exercise training and infarction in isolated canine myocardium
Authors: Fazlollahi Farbod , Santini Gonzalez Jorge J. , Repas Steven J. , Canan Benjamin D. , Billman George E. , Janssen Paul M.L.
Published: April 2021

The two main phases of the mammalian cardiac cycle are contraction and relaxation; however, whether there is a connection between them in humans is not well understood. Routine exercise has been shown to improve cardiac function, morphology, and molecular signatures. Likewise, the acute and chronic changes that occur in the heart in response to injury, disease, and stress are well characterized, albeit not fully understood. In this study, we investigated how exercise and myocardial injury affect contraction–relaxation coupling. We retrospectively analyzed the correlation between the maximal speed of contraction and the maximal speed of relaxation of canine myocardium after receiving surgically induced myocardial infarction, followed by either sedentary recovery or exercise training for 10–12 wk. We used isolated right ventricular trabeculae, which were electrically paced at different lengths, frequencies, and with increasing β-adrenoceptor stimulation. In all conditions, contraction and relaxation were linearly correlated, irrespective of injury or training history. Based on these results and the available literature, we posit that contraction–relaxation coupling is a fundamental myocardial property that resides in the structural arrangement of proteins at the level of the sarcomere and that this may be regulated by the actions of cardiac myosin binding protein C (cMyBP-C) on actin and myosin.
Photoelectron angular distribution studies for two spin–orbit-split components of Xe 3d subshell: a critical comparison between theory and experiment
Authors: Minemoto S , Teramoto T , Majima T , Mizuno T , Mun J H , Park S H , Kwon S , Yagishita A , Toffoli D
Published: April 2021

The photoelectron angular distribution asymmetry parameters β of the Xe 3d subshell were investigated using an x-ray free-electron laser (XFEL) at photon energies of 750 and 800 eV. Owing to the perfect polarization of the XFEL and two-dimensional momentum imaging capability of our velocity map imaging spectrometer, we determined the β values with high accuracy. The β values were also investigated based on relativistic time-dependent density functional theory calculations of up to 900 eV of photon energies. By comparing all the available experimental results including our data with the most reliable theories on the photon energy dependence of the β parameters, serious differences are noted between the experiments and theories. Further studies on resolving this difference will provide new insight into the photoionization processes of the deep inner shells.
Skyrmions at vanishingly small Dzyaloshinskii–Moriya interaction or zero magnetic field
Authors: Bera Sandip , Mandal Sudhansu S
Published: April 2021

By introducing biquadratic together with usual bilinear ferromagnetic nearest neighbor exchange interaction in a square lattice, we find that the energy of the spin-wave mode is minimized at a finite wavevector for a vanishingly small Dzyaloshinskii–Moriya interaction (DMI), supporting a ground state with spin-spiral structure whose pitch length is unusually short as found in some of the experiments. Apart from reproducing the magnetic structures that can be obtained in a canonical model with nearest neighbor exchange interaction only, a numerical simulation of this model with further introduction of magnetic anisotropy and magnetic field predicts many other magnetic structures some of which are already observed in the experiments. Among many observed structures, nanoscale skyrmion even at vanishingly small DMI is found for the first time in a model. The model provides the nanoscale skyrmions of unit topological charge at zero magnetic field as well. We obtain phase diagrams for all the magnetic structures predicted in the model.
Revisiting density-functional theory of the total current density
Authors: Laestadius Andre , Penz Markus , Tellgren Erik I
Published: April 2021

Density-functional theory (DFT) requires an extra variable besides the electron density in order to properly incorporate magnetic-field effects. In a time-dependent setting, the gauge-invariant, total current density takes that role. A peculiar feature of the static ground-state setting is, however, that the gauge-dependent paramagnetic current density appears as the additional variable instead. An alternative, exact reformulation in terms of the total current density has long been sought but to date a work by Diener is the only available candidate. In that work, an unorthodox variational principle was used to establish a ground-state DFT of the total current density as well as an accompanying Hohenberg–Kohn-like result. We here reinterpret and clarify Diener’s formulation based on a maximin variational principle. Using simple facts about convexity implied by the resulting variational expressions, we prove that Diener’s formulation is unfortunately not capable of reproducing the correct ground-state energy and, furthermore, that the suggested construction of a Hohenberg–Kohn map contains an irreparable mistake.
Quasiparticle electronic structure of two-dimensional heterotriangulene-based covalent organic frameworks adsorbed on Au(111)
Authors: Frimpong Joseph , Liu Zhen-Fei
Published: April 2021

The modular nature and unique electronic properties of two-dimensional (2D) covalent organic frameworks (COFs) make them an attractive option for applications in catalysis, optoelectronics, and spintronics. The fabrications of such devices often involve interfaces formed between COFs and substrates. In this work, we employ the first-principles GW approach to accurately determine the quasiparticle electronic structure of three 2D carbonyl bridged heterotriangulene-based COFs featuring honeycomb–kagome lattice, with their properties ranging from a semi-metal to a wide-gap semiconductor. Moreover, we study the adsorption of these COFs on Au(111) surface and characterize the quasiparticle electronic structure at the heterogeneous COF/Au(111) interfaces. To reduce the computational cost, we apply the recently developed dielectric embedding GW approach and show that our results agree with existing experimental measurement on the interfacial energy level alignment. Our calculations illustrate how the many-body dielectric screening at the interface modulates the energies and shapes of the Dirac bands, the effective masses of semiconducting COFs, as well as the Fermi velocity of the semi-metallic COF.
Critical implementation issues of excitation signals for embedded wearable bioimpedance spectroscopy systems with limited resources
Authors: Kallel A Y , Bouchaala D , Kanoun O
Published: April 2021

Wideband excitation signals are essential in bioimpedance spectroscopy for measurements in a time ensuring a quasi-stable measurement condition. In particular, for wearable biomedical systems, due to limited system resources, several aspects regarding measurement time, crest factor, slew rate requirements, frequency distribution, amplitude spectrum, and energy efficiency need to be thoroughly investigated. In this paper, we present an investigation of excitation signals, which includes not only the theoretical aspects but also aspects of real implementation on microcontroller-based systems. At a fixed number of samples and sampling rate, we investigate the implementability of signal frequencies and the resulting spectral efficiency. We focus on sources of signal distortion due to timer and amplitude deviations. The results show that for 4096 samples and a sampling frequency of 1 MHz, wideband signals are 2.76 times faster than a stepped frequency sweep. The multisine signal provides a better energy efficiency and has a lower slew rate requirement on hardware (around 0.3 V µs−1), but has a relatively high crest factor, even after optimization. An exemplary investigation of the distortion of the time/frequency and amplitudes following implementation on a standard industrial advanced RISC machines microcontroller has shown that a sampling rate compensation is required to overcome timer inaccuracies. Furthermore, non-return-to-zero binary signals are more sensitive to distortion due to hardware-related issues and have a lower signal-to-distortion-and-noise (SINAD) ratio than 24 dB, which is lower than the multisine signal, having a SINAD of 31 dB.
Room temperature monitoring of SF6decomposition byproduct SO2F2based on TiO2/NiSO4composite nanofibers
Authors: Li Li , Din Salah Ud , ul Haq Mahmood , Tang Nian , Zhang Manjun , Rahman Nasir , Zhu Liping
Published: April 2021

Sulfuryl fluoride (SO2F2) is one of the ideal decomposition components of sulfur hexafluoride (SF6), which is widely used as an insulating and arc extinguishing medium in gas-insulated switchgear. To detect the decomposition component of SF6at room temperature, the use of SO2F2is still a challenge. In this work, we have successfully fabricated TiO2nanofibers and nickel sulfate (NiSO4NPs) via simple electrospun and hydrothermal methods, followed by calcination process to improve the sensing performance. Metal oxide semiconductor materials (MOSs) are widely used in gas sensing applications due to their superior performance and fast recovery speed. Although the performance of our TiO2/NiSO4composite nanofiber sensor decreases at higher temperatures, it shows an excellent response to target gasses at room temperature. Ni-decoration on the outer surface of the nanofibers could maximize the sensing response of 100 ppm SO2F2by up to 189% at room temperature, showing that the TiO2/NiSO4composite nanofibers are 2.5 times superior to the pure TiO2nanofiber sensors. Thus, the approach for this novel composite nanofiber-based material is promising for the fabrication of superior gas sensors for decomposition of SF6.
Nitrogen doped porous carbon coated antimony as high performance anode material for sodium-ion batteries
Authors: Luo Xinyuan , Tan Hengfeng , Ma Ting , Wang Hui , lv Miao , Yu Zhou , Fu Caiping , Chang Xinghua , Jin Shengming
Published: April 2021

Sb holds the promise of being a high performance anode for sodium ion batteries(SIBs), while effective preparation of decent antimony(Sb) based anode materials for sodium storage is still under exploration. Herein, we propose a simple approach to achieve a high performance anode, using polyaniline as the carbon source and SbCl3 as the metal source. Synergetic polymerization and hydrolysis reactions combined with subsequent thermal reduction endow Sb/C-PANI electrode possessing ultrafine Sb nanoparticles symmetrically distributed in the nitrogen(N) doped porous carbon matrix. The Sb/C-PANI electrode exhibits excellent sodium storage performance, featured for a high reversible capacity of 469.5 mAh g−1 after 100 cycles at 100 mA g−1 and 336.5 mAh g−1 after 300 cycles under 500 mA g−1. Such impressive performance will advance the development of Sb based anode materials for sodium storage. The present approach provides a compatible strategy for preparation of anode materials with high reversible capacity and long lifespan.
Analytic solutions for delocalized heat transport
Authors: Lu Chao , Tikhonchuk Vladimir , Weber Stefan
Published: April 2021

Comprehensive understanding of nonlocal transport is mandatory for many applications of laser–plasma interaction physics, such as inertial confinement fusion and modeling of astrophysical phenomena in the laboratory. Theoretical description is important for guiding numerical simulations and experiments. In this article, an analytic approach is developed: by using a simple integral differential model, we calculate the preheating of plasma upstream of the heat front associated with nonlocal transport. A detailed comparison of various transport configurations as a function of the boundary conditions and the nonlinearity parameter is presented in the context of laser–plasma interaction. Three important results are demonstrated in this paper. First, analytical expressions for all possible self-similar solutions of local nonlinear transport are obtained. Second, a systematic comparison of various nonlocal kernels and forms of the delocalization length is performed. Third, an analytic expression for the temperature profile upstream of the heat front is obtained.
Charged particle transport across an obstacle in a non-flowing partially magnetized plasma column
Authors: Das Satadal , Karkari S K
Published: April 2021

A wake is created in a plasma when a macroscopic body blocks the flow of charged particles from entering in to a downstream plasma region. The phenomena leads to a strong depletion in charged particle density behind the obstacle. In this paper, charged particle transport inside an ionization free region behind a macroscopic obstacle has been investigated for the case of a non-flowing, partially magnetized plasma column. Surprisingly, it is found that the transport of hotter electron population inside the void region is enhanced due to the application of axial magnetic field. Furthermore, the radial plasma density and potential variation inside the obstructed region show an opposing trend than the region outside the obstacle. A phenomenological model is given to explain the mechanism behind observing these trends.
The effect of a negative direct-current voltage on striated structures and electrical parameters in a capacitively coupled rf discharge in CF4
Authors: Wang Xiao-Kun , Liu Yong-Xin , Wang Xiang-Yu , Zhang Quan-Zhi , Zhao Kai , Wang You-Nian
Published: April 2021

The effects of a negative direct-current (dc) voltage on the striated structures and the electrical parameters have been studied by multi-fold experimental diagnostics and particle-in-cell/Monte Carlo collision (PIC/MCC) simulations in a dc superposed rf (radio-frequency, 8 MHz) capacitive discharge in CF4. The electron density, the spatio-temporal distribution of electron-impact excitation rate and the electrical parameters measured by a hairpin probe, phase resolved optical emission spectroscopy

P
R
O
E
S

and a voltage and a current probe are compared with the corresponding simulation results. With the increase of the magnitude of the dc voltage,

V

dc

, all the experimental observations are well reproduced and analyzed by the simulations. It was found that the plasma bulk is compressed and the electron density decreases slightly at low

V

dc

, while the plasma bulk broadens at high

V

dc

when the ionization at the edge of the completely expanded sheath adjacent to the powered electrode is significantly enhanced due to the secondary electron emission (SEE). By increasing

V

dc

, the region of the strong ionization/excitation shrinks towards the edge of the collapsing sheath adjacent to the grounded electrode. And the ionization inside the bulk region is significantly suppressed during the collapsing phase of the sheath adjacent to the powered electrode. This is mainly attributed to the fact that the dc component of the bulk electric field and the spatial gradient of the electron density are simultaneously enhanced during the transition from the ‘striation’ mode to ‘striation-γ’ hybrid mode when increasing

V

dc

. Besides, we found that increasing

V

dc

can somewhat suppress the rf power deposition at low

V

dc

, and enhance the rf power deposition at high

V

dc

. The magnitude of the dc current exhibits a complex dependence on

V

dc

, due to nonlinear change of the dc resistance of the plasma.
A 4 × 4 8T-SRAM array with single-ended read and differential write scheme for low voltage applications
Authors: Duari Chusen , Birla Shilpi , Singh Amit Kumar
Published: April 2021

In ultra-low-power applications, the design of power-efficient static random access memory (SRAM) is a major concern as it plays a significant part in leakage due to its higher density. In this paper, we have designed a power-efficient SRAM array that efficiently utilizes our SRAM cell for low-power and reliable memory applications. The proposed SRAM array is designed with an optimized 8T SRAM cell with minimum leakage and improved stability. The cell designed with 22 nm CMOS technology uses a stacking effect to further enhance leakage reduction and transmission gate as an access transistor to obtain better stability. Peripheral circuitry like address decoder, write driver, pre-charge, and sense amplifier are designed with optimum transistor sizing to get superior results in terms of area occupied and power consumption. The read and write access time for the cell is found to be 12 ps and 10 ps respectively. In line with the 22 nm technology node, the power is calculated for the array as 0.42 µW.
A novel strategy to enhance the generating power of ionic polymer metal composites through magnetoelectricity
Authors: Tang Gangqiang , Wang Yanjie , Hao Muyu , Zhang Lei , Ru Jie , Chang Longfei , Li Lijie
Published: April 2021

In this paper, we put forward a method to enhance the output power of ionic polymer metal composite (IPMC) through a magnetic field by combining the ion-electronic and magnetoelectric effects. Firstly, we confirmed that the total output voltage of IPMC deformation originates from the vector superposition of ion-electronic and magnetoelectric effects when applied a magnetic field. The open circuit voltage and output power of IPMC were experimentally investigated by adjusting the deflecting frequency and magnetic field intensity. As the frequency and magnetic field intensity increase, the increased voltage and output power caused by the magnetic field show an upward trend. Then, the experimental results were analyzed and verified through the piezoelectric and magnetoelectric theory. The results show that the increased voltage has a linear relationship with the frequency and magnetic field intensity and has nothing to do with the inherent parameters of IPMC itself. Finally, we performed simulation and practical tests to verify the energy harvesting effect of this strategy. During the energy harvesting test of water flow fluctuation, the open circuit voltage was increased by 41.91% and the output energy was increased by 110.03%, which indicates that this strategy has excellent performance in practical applications. By this study, the power generation performance of IPMC was explored and improved through multiple physical mechanisms.
Seismic performance of magnetorheological damped structures with different MR fluid perfusion densities of the damper
Authors: Yang Yang , Xu Zhao-Dong , Guo Ying-Qing
Published: April 2021

Performance tests of magnetorheological (MR) dampers show that the hysteresis curves generally show an obvious force–lag phenomenon, which is due to the presence of trapped air in the working chamber of the damper. However, the force–lag phenomenon is barely considered in existing studies, and its influence on the seismic performance of MR damped structures is still unclear. In this paper, experimental and theoretical research have been carried out to analyze the force–lag phenomenon and its influence. Firstly, a specially designed MR damper was manufactured so that MR fluid can be poured into the damper successively for several times until the working chamber was filled, and performance tests were carried out correspondingly with different MR fluid perfusion densities (a parameter introduced in this paper to describe the volume fraction of MR fluid in the working chamber). The mechanical properties of the MR damper under different MR fluid perfusion densities were compared to reveal the influence of the force–lag phenomenon. Then, the effects of excitation properties on the force–lag phenomenon were discussed by comparing experiments results under different currents, frequencies and displacement amplitudes. Further, a force–lag mathematical model was proposed by considering the variation of the force-lag part with MR fluid perfusion density to reflect the force–lag phenomenon with different volume fractions of trapped air, and then verified based on the performance test data. Finally, numerical analysis of MR damped structures with different MR fluid perfusion densities was performed using the proposed force–lag mathematical model. Results show that the damping effect of MR control systems will be weaken due to the force–lag phenomenon, and with the increase of the MR fluid perfusion density, the seismic performance of MR damped structures will gradually improve.