bluuebunny/crossref_metadata_2025 huggingface dataset:
Mélange of Lymphoepithelial Lesions of Salivary Glands from a Tertiary Care Center of North East India: Diagnostic Conundrums
Authors: Chowdhury Zachariah , Raphael Vandana , Khonglah Yookarin , Mishra Jaya , Marbaniang Evarisalin , Dey Biswajit
Published: July 2021

Background Lymphocytic infiltrates of the major salivary glands are involved in a spectrum of diseases that range from reactive to benign and malignant neoplasms. Occasionally, these pathologic entities present difficulties in the clinical and pathological diagnosis.

Aim and Objective The aim of this study was to highlight the importance of meticulous cytopathological and histopathological examination (HPE) in solving the diagnostic challenges encountered in the analysis of these salivary gland lesions.

Materials and Methods A retrospective analysis of salivary gland lesions was undertaken over a period of 5 years from 2013 to 2018 in the Department of Pathology at our institute. Salivary gland pathologies diagnosed either as chronic sialadenitis or reactive/benign/malignant lymphoepithelial lesions on fine-needle aspiration cytology (FNAC) and as lymphoepithelial carcinoma (LEC) were included in this study.

Results A total of 86 cases of salivary gland lesions diagnosed as mentioned above were found during this period. Out of the 86 cases, 16 were subjected to HPE. Biopsy was not warranted in most of the cases diagnosed as chronic sialadenitis. HPE was concordant with the FNAC diagnoses in 13 out of the 16 cases (81.3%), with a single case misinterpreted as LEC on FNAC.

Conclusion Benign and malignant lymphoepithelial lesions of salivary glands may sometimes be difficult to differentiate not only from one another on FNAC but also from other malignant lesions. FNAC is an effective tool for the diagnosis of nonneoplastic lesions, but in cases of benign lymphoepithelial lesions in the absence of salivary acini, biopsy is advisable.
Sperm Selection Technology in ART
Authors: Martin Catherine , Woodland Emma
Published: July 2021

Intracytoplasmic sperm injection (ICSI) is a commonly used in vitro fertilization technique. Selection of sperm for injection is currently done using subjective assessment of morphology, which may not accurately identify the best-quality sperm. Hyaluronic acid receptors on sperm plasma membranes are a marker of maturity, and sperms which are capable of binding immobilized hyaluronic acid in vitro are of higher quality. This can be used as an advanced sperm selection technique to choose sperm for ICSI, termed physiological ICSI (PICSI). Several studies reported improved fertility treatment outcomes when using PICSI compared with conventional ICSI; however, the majority of studies are underpowered. Recently, a large, multicenter, randomized controlled trial, known as the Hyaluronic Acid Binding Sperm Selection (HABSelect) trial, found a significant reduction in miscarriage rates with PICSI, but no significant effect on live birth rate. There are still many avenues through which PICSI may provide an advantage, subject to confirmation by future research, such as improved long-term health of offspring. Other advanced sperm selection techniques include intracytoplasmic morphologically selected sperm injection, magnetic-activated cell sorting, and Zeta potential sperm selection; however, the most recent Cochrane review concluded that there is currently insufficient evidence to ascertain whether these techniques improve clinical outcomes, such as live birth rates.
Fluid dynamics model provides numerical framework for optimizing 3D bioprinting parameters
Authors: Liebendorfer Adam
Published: July 2021

Addressing bubble dynamics and jet flow regimes leads to improved quality of laser-induced-forward-transfer bioprints.
Spatial characteristics of rotating magnetic field (RMF) plasma acceleration method in open magnetic field configuration under partial RMF penetration
Authors: Furukawa T. , Kuwahara D. , Shinohara S.
Published: July 2021

In typical electrodeless radio frequency plasma thrusters, application of a rotating magnetic field (RMF) is expected to drive an azimuthal electron current via the non-linear Hall-term effect, resulting in an additional electromagnetic acceleration effect in the presence of a diverging magnetic field. Large increases in ion Mach number and electron density were found, comparing cases with and without the RMF, under a partial RMF penetration into a plasma. Spatial characteristics of the RMF acceleration were investigated to clarify the causes of these increments: 2D profiles of plasma parameters and time-varying RMF components were measured. Partial penetration of the RMF into plasma with a phase retardation was found, but the RMF azimuthal current was driven. Large diamagnetic current derived from the large density gradient also increased by the RMF application. Synergistic acceleration effect derived from the driven RMF current and the density gradient results in the plasma acceleration effect even under the partial penetration.
Enhanced sensitivity of resonant liquid sensors by phononic crystals
Authors: Lucklum Ralf , Mukhin Nikolay
Published: July 2021

Mechanical resonators have a long tradition. We concentrate on new results with a sensor for liquid analytes, the phononic crystal (PnC) sensor. Here, the liquid analyte becomes the integral part of a phononic crystal. The liquid-filled cavity acts as a defect in an otherwise regular structure. The sensor probes the entire liquid volume. The primary sensor input value is the speed of sound in the liquid; the primary output parameter is a shift in the resonance frequency. We theoretically analyze 1D- and 2D-PnC sensors. An optimal relation of frequency shift and bandwidth of the resonance is the key to an enhanced sensitivity of the sensor to liquid analyte properties. We introduce a new 2D PnC sensor design concept: The sensor-specific feature is an analyte-filled point defect. This defect becomes the analyte-filled capillary in the real sensor. This is the step toward the integration of PnC and microfluidic components. Electromechanical transducers excite and detect longitudinal acoustic waves along the channel, not at the front ends of the capillary. The sensor-specific task of the 2D-PnC is the conversion of this longitudinal wave into the axisymmetric mode in the liquid-filled cavity. In contrast to other modes, this mode avoids shear displacement at the solid–liquid interface and thereby absorption of acoustic energy due to liquid shear viscosity. Experiments prove the correctness of our approach.
Shock response of micro-grained diamond-SiC composite
Authors: Li Yuanyuan , Zhang Lu , Yu Yin , Zhang Youjun , Wang Qiming , Cao Xiuxia , Gan Bo , Zhou Xianming , Meng Chuanmin , He Hongliang , He Duanwei
Published: July 2021

Micro-grained diamond-SiC composites have been prepared by sintering a mixture of micro-grained diamond and Si powder using high-temperature and high-pressure method at 1100–1500 °C, and 5.5 GPa. Plate impact experiments in reverse—and forward—impact geometry were used to investigate the shock response of the micro-grained diamond-SiC composites within a shock pressure range from 22 to 195 GPa. The obtained plot of shock velocity (D) vs particle velocity (u) indicated that the double elastic wave responses are observed in the pressure range of 22–170 GPa, which is consistent with the previously reported diamond-SiC composites containing a small amount of tungsten carbide (WC) under shock compression up to ∼110 GPa [Li et al., J. Appl. Phys. 128, 245901 (2020)]. The results of shock experiments demonstrate that the Hugoniot elastic limit of micro grained diamond in SiC matrix is as high as 170 GPa, which is nearly twice as high as that of single crystal diamond.
Coupling between cardiac cells—An important determinant of electrical impulse propagation and arrhythmogenesis
Authors: Kléber André G. , Jin Qianru
Published: July 2021

Cardiac arrhythmias are an important cause of sudden cardiac death—a devastating manifestation of many underlying causes, such as heart failure and ischemic heart disease leading to ventricular tachyarrhythmias and ventricular fibrillation, and atrial fibrillation causing cerebral embolism. Cardiac electrical propagation is a main factor in the initiation and maintenance of cardiac arrhythmias. In the heart, gap junctions are the basic unit at the cellular level that host intercellular low-resistance channels for the diffusion of ions and small regulatory molecules. The dual voltage clamp technique enabled the direct measurement of electrical conductance between cells and recording of single gap junction channel openings. The rapid turnover of gap junction channels at the intercalated disk implicates a highly dynamic process of trafficking and internalization of gap junction connexons. Recently, non-canonical roles of gap junction proteins have been discovered in mitochondria function, cytoskeletal organization, trafficking, and cardiac rescue. At the tissue level, we explain the concepts of linear propagation and safety factor based on the model of linear cellular structure. Working myocardium is adequately represented as a discontinuous cellular network characterized by cellular anisotropy and connective tissue heterogeneity. Electrical propagation in discontinuous cellular networks reflects an interplay of three main factors: cell-to-cell electrical coupling, flow of electrical charge through the ion channels, and the microscopic tissue structure. This review provides a state-of-the-art update of the cardiac gap junction channels and their role in cardiac electrical impulse propagation and highlights a combined approach of genetics, cell biology, and physics in modern cardiac electrophysiology.
Fractal generation in a two-dimensional active-nematic fluid
Authors: Mitchell Kevin A. , Tan Amanda J. , Arteaga Jorge , Hirst Linda S.
Published: July 2021

Active fluids, composed of individual self-propelled agents, can generate complex large-scale coherent flows. A particularly important laboratory realization of such an active fluid is a system composed of microtubules, aligned in a quasi-two-dimensional (2D) nematic phase and driven by adenosine-triphosphate-fueled kinesin motor proteins. This system exhibits robust chaotic advection and gives rise to a pronounced fractal structure in the nematic contours. We characterize such experimentally derived fractals using the power spectrum and discover that the power spectrum decays as k−β for large wavenumbers k. The parameter β is measured for several experimental realizations. Though β is effectively constant in time, it does vary with experimental parameters, indicating differences in the scale-free behavior of the microtubule-based active nematic. Though the fractal patterns generated in this active system are reminiscent of passively advected dye in 2D chaotic flows, the underlying mechanism for fractal generation is more subtle. We provide a simple, physically inspired mathematical model of fractal generation in this system that relies on the material being locally compressible, though the total area of the material is conserved globally. The model also requires that large-scale density variations are injected into the material periodically. The model reproduces the power-spectrum decay k−β seen in experiments. Linearizing the model of fractal generation about the equilibrium density, we derive an analytic relationship between β and a single dimensionless quantity r, which characterizes the compressibility.
Use of autoionization to measure microwave-driven transitions between high-n strontium Rydberg states
Authors: Brienza R. , Fields G. , Dunning F. B.
Published: July 2021

The use of autoionization as a tool to quantitatively analyze transitions between high-n strontium Rydberg states with low-to-intermediate values of L is described and is demonstrated through observations of Rabi oscillations when driving 5snf 1F3 → 5s(n + 1)g 1G4, 5snf 1F3 → 5s(n + 2)h 1H5, and 5snp 1P1 → 5s(n + 1)d 1D2 transitions using microwave fields. The technique is shown to offer advantages when compared to selective field ionization and can be used with other alkaline-earth and alkaline-earth-like metals.
On the concept of an effective temperature Seebeck ratchet
Authors: Kompatscher Anton , Kemerink Martijn
Published: July 2021

In disordered semiconductors, finite electric fields can heat up the charge carrier distribution to effective temperatures that can significantly exceed the lattice temperature. Here, we demonstrate that such effective temperatures can be utilized to drive a thermoelectric generator (TEG). We use this concept in a variant of the Seebeck ratchet, which was originally introduced by Büttiker, in which out-of-phase spatial modulations of the electrostatic potential and the (effective) temperature cause a DC current. In contrast to conventional TEGs, this design utilizes only a single doped semiconductor and works in a thin film geometry. We demonstrate the concept using kinetic Monte Carlo simulations and show that the proposed concept can outperform conventional TEGs of the same material. We provide an analytical model that semiquantitatively reproduces the numerical results. Finally, we propose how such a device might be realized.
SO-FDTD analysis on transmission characteristics of terahertz wave in plasma
Authors: Zhou Zhikun , Wan Xiaohuan , Li Xiaolin , Zhang Juan , Zhou Yushan , Ren Xueping , Shi Yuren
Published: July 2021

The propagation characteristics of terahertz waves in high-temperature magnetized inhomogeneous plasma sheath were investigated theoretically by the shift operator finite difference time domain method. Both the transmission characteristics of left and right circularly polarized terahertz waves propagating in uniform or non-uniform plasma were analyzed. Simulation results reveal that the transmission characteristics of terahertz waves in plasma will be influenced by plasma parameters and the external magnetic field. The plasma sheath has a high pass filtering characteristic to terahertz waves, which provides a significant theoretical basis, to a certain extent, for the “blackout” problem.
Theoretical analysis of efficiency for vacuum photoelectric energy converters with plasmon-enhanced electron emitter
Authors: Luo Shisong , Chen Yicong , Li Zhibing , Chen Jun
Published: July 2021

Thermionic energy converters (TECs) convert heat or light into electrical energy based on electron emission in vacuum. By using a cathode consisting of metal nanostructures, plasmonic thermionic energy converters (PTECs) can overcome challenges concerning high operation temperature, which hinders the use of TEC for solar–thermal energy conversion. However, there is lack of theoretical analysis to describe the mechanism behind PTEC and to guide the design of device. In this study, we developed a simple model to calculate the power conversion efficiency of PTEC consisting of metal nanostructure cathodes, also named as vacuum photoelectric energy converter (VPEC) with plasmon-enhanced electron emitter, in this work. The distribution of plasmon-induced hot electrons was calculated using Fermi's golden rule. Under the assumption of ballistic transport and photoemission, the performance of VPEC was analyzed under different operating conditions. The results reveal that the size and shape of the nanostructure cathode influence the hot electron emission efficiency. For a cathode consisting of a single silver nanosphere, an optimal nanosphere diameter of ∼15 nm exists with optimal quantum efficiency and energy conversion of 8.71% and 1.88%, respectively, under the illumination of 339 nm light. Besides, the optimal performance for cathode consisting of a silver nanosphere array is ∼33% of that for the single silver nanosphere. This model provides insights into the dynamics of plasmon-induced hot electrons and guidelines for optimizing hot electron devices for photoelectric conversion applications.
Bistability in a tri-trophic food chain model: Basin stability perspective
Authors: Pattanayak Debarghya , Mishra Arindam , Dana Syamal K. , Bairagi Nandadulal
Published: July 2021

The most important issue of concern in a food chain is the stability of species and their nature of persistence against system parameter changes. For understanding the stable dynamics and their response against parameter perturbation, the local stability analysis is an insufficient tool. A global stability analysis by the conventional techniques seems to supplement some of the shortcomings, however, it becomes more challenging for multistable ecosystems. Either of the techniques fails to provide a complete description of the complexity in dynamics that may evolve in the system, especially, when there is any transition between the stable states. A tri-trophic resource–consumer–predator food chain model has been revisited here that shows bistability and transition to monostability via a border collision that leads to a state of predator extinction. Although earlier studies have partially revealed the dynamics of such transitions, we would like to present additional and precise information by analyzing the system from the perspective of basin stability. By drawing different bifurcation diagrams against three important parameters, using different initial conditions, we identify the range of parameter values within which the stability of the states persists and changes to various complex dynamics. We emphasize the changes in the geometry of the basins of attraction and get a quantitative estimate of the nature of relative changes in the area of the basins (basin stability) during the transitions. Furthermore, we demonstrate the presence of a down-up control, in addition to the conventional bottom-up and top-down control phenomena in the food chain. The application of basin stability in food networks will go a long way for accurate analysis of their dynamics.
Assessment and prediction of band edge locations of nitrides using a self-consistent hybrid functional
Authors: Kim Se-Jun , Lebègue Sébastien , Kim Hyungjun , Kim Won June
Published: July 2021

Due to their optimal bandgap size and large defect tolerance, nitrides are becoming pivotal materials in several optoelectronic devices, photovoltaics, and photocatalysts. A computational method that can accurately predict their electronic structures is indispensable for exploring new nitride materials. However, the relatively small bandgap of nitrides, which stems from the subtle balance between ionic and covalent bond characteristics, makes conventional density functional theory challenging to achieve satisfactory accuracy. Here, we employed a self-consistent hybrid functional where the Hartree–Fock mixing parameter is self-consistently determined and thus the empiricism of the hybrid functional is effectively removed to calculate the bandgaps of various nitride compounds. By comparing the bandgaps from the self-consistent hybrid functional calculations with the available experimental and high-level GW calculation results, we found that the self-consistent hybrid functional can provide a computationally efficient approach for quantitative predictions of nitride electronic structures with an accuracy level comparable to the GW method. Additionally, we aligned the band edge positions of various nitride compounds using self-consistent hybrid functional calculations, providing material design principles for heterostructures of nitride-based optoelectronic devices. We anticipate the wide use of the self-consistent hybrid functional for accelerating explorations and predictions of new nitride-based functional materials in various photoactive applications.
Evaluation of two-particle properties within finite-temperature self-consistent one-particle Green’s function methods: Theory and application to GW and GF2
Authors: Pokhilko Pavel , Iskakov Sergei , Yeh Chia-Nan , Zgid Dominika
Published: July 2021

One-particle Green’s function methods can model molecular and solid spectra at zero or non-zero temperatures. One-particle Green’s functions directly provide electronic energies and one-particle properties, such as dipole moment. However, the evaluation of two-particle properties, such as ⟨S2⟩ and ⟨N2⟩, can be challenging because they require a solution of the computationally expensive Bethe–Salpeter equation to find two-particle Green’s functions. We demonstrate that the solution of the Bethe–Salpeter equation can be completely avoided. Applying the thermodynamic Hellmann–Feynman theorem to self-consistent one-particle Green’s function methods, we derive expressions for two-particle density matrices in a general case and provide explicit expressions for GF2 and GW methods. Such density matrices can be decomposed into an antisymmetrized product of correlated one-electron density matrices and the two-particle electronic cumulant of the density matrix. Cumulant expressions reveal a deviation from ensemble representability for GW, explaining its known deficiencies. We analyze the temperature dependence of ⟨S2⟩ and ⟨N2⟩ for a set of small closed-shell systems. Interestingly, both GF2 and GW show a non-zero spin contamination and a non-zero fluctuation of the number of particles for closed-shell systems at the zero-temperature limit.
Engineering skeletal muscle tissues with advanced maturity improves synapse formation with human induced pluripotent stem cell-derived motor neurons
Authors: Santoso Jeffrey W. , Li Xiling , Gupta Divya , Suh Gio C. , Hendricks Eric , Lin Shaoyu , Perry Sarah , Ichida Justin K. , Dickman Dion , McCain Megan L.
Published: July 2021

To develop effective cures for neuromuscular diseases, human-relevant in vitro models of neuromuscular tissues are critically needed to probe disease mechanisms on a cellular and molecular level. However, previous attempts to co-culture motor neurons and skeletal muscle have resulted in relatively immature neuromuscular junctions (NMJs). In this study, NMJs formed by human induced pluripotent stem cell (hiPSC)-derived motor neurons were improved by optimizing the maturity of the co-cultured muscle tissue. First, muscle tissues engineered from the C2C12 mouse myoblast cell line, cryopreserved primary human myoblasts, and freshly isolated primary chick myoblasts on micromolded gelatin hydrogels were compared. After three weeks, only chick muscle tissues remained stably adhered to hydrogels and exhibited progressive increases in myogenic index and stress generation, approaching values generated by native muscle tissue. After three weeks of co-culture with hiPSC-derived motor neurons, engineered chick muscle tissues formed NMJs with increasing co-localization of pre- and postsynaptic markers as well as increased frequency and magnitude of synaptic activity, surpassing structural and functional maturity of previous in vitro models. Engineered chick muscle tissues also demonstrated increased expression of genes related to sarcomere maturation and innervation over time, revealing new insights into the molecular pathways that likely contribute to enhanced NMJ formation. These approaches for engineering advanced neuromuscular tissues with relatively mature NMJs and interrogating their structure and function have many applications in neuromuscular disease modeling and drug development.
Generative adversarial networks for transition state geometry prediction
Authors: Makoś Małgorzata Z. , Verma Niraj , Larson Eric C. , Freindorf Marek , Kraka Elfi
Published: July 2021

This work introduces a novel application of generative adversarial networks (GANs) for the prediction of starting geometries in transition state (TS) searches based on the geometries of reactants and products. The multi-dimensional potential energy space of a chemical reaction often complicates the location of a starting TS geometry, leading to the correct TS combining reactants and products in question. The proposed TS-GAN efficiently maps the space between reactants and products and generates reliable TS guess geometries, and it can be easily combined with any quantum chemical software package performing geometry optimizations. The TS-GAN was trained and applied to generate TS guess structures for typical chemical reactions, such as hydrogen migration, isomerization, and transition metal-catalyzed reactions. The performance of the TS-GAN was directly compared to that of classical approaches, proving its high accuracy and efficiency. The current TS-GAN can be extended to any dataset that contains sufficient chemical reactions for training. The software is freely available for training, experimentation, and prediction at https://github.com/ekraka/TS-GAN.
Time-resolved measurement of magnetization vectors driven by pulsed spin–orbit torque
Authors: Choi Young-Gwan , Choi Gyung-Min
Published: July 2021

Spin–orbit torque (SOT) enables the efficient manipulation of magnetization with charge current injection. Electronic measurement techniques have been widely used as common experimental tools for SOT analysis (e.g., anomalous Hall measurement, spin-transfer ferromagnetic resonance, and planar Hall effect). However, electronics-based techniques usually observe the final static states of the magnetization motion of the ferromagnetic layer, and it is difficult to observe detailed kinetics during ultrafast operation. Here, we introduce a time-resolved measurement technique for a pulsed SOT. We investigate the precessional motion of the magnetization vector, driven by a pulsed SOT, employing the time-resolved magneto-optical Kerr effect. A fabricated photoswitch can convert an optical pulse into a charge current pulse that results in a pulsed SOT. We believe that this time- and vector-resolved measurement would be useful for studying the underlying mechanisms of SOT.
Extra high-Q resonances and extraordinary transparency in finite fragments of dielectric metasurfaces: Prospects for 5G applications
Authors: Jamilan Saeid , Kumar Varsha Vijay , Danyal Muhammad , Semouchkina Elena
Published: July 2021

We investigate the effects of fragmenting metasurfaces (MSs), composed of dielectric disks, on their electromagnetic responses and show that the presence of four abrupt boundaries between finite size structures and free space leads to the formation of new resonance modes. In addition to the characteristic for infinite metasurfaces modes with identical dipolar resonances formed in all unit cells, fragmented metasurfaces can exhibit out-of-phase electric and magnetic responses in neighboring “meta-atoms.” While in-phase responses correspond to field patterns representative for even resonance modes, out-of-phase responses produce a variety of patterns typical for odd resonance modes. These modes are formed as the result of partial reflections of surface waves from boundaries between MS fragments and free space, and their respective responses demonstrate extremely high intensities and Q-factors. Enabled by new responses, a significantly localized wave/matter interaction can be used for enhancing the performance of sensors and absorbers of 5G systems. In addition, we report the detection of extraordinary narrow-band transmission at electric and magnetic dipolar resonances in fragmented MSs that can be used to locally enhance mm-wave signals for 5G communications. As a proof of concept, transmission through a 5 × 5 MS fragment has been experimentally confirmed in the X-band of microwave spectrum.
Phase-dynamic causalities within dynamical effects framework
Authors: Smirnov Dmitry A.
Published: July 2021

This work investigates numerics of several widely known phase-dynamic quantifiers of directional (causal) couplings between oscillatory systems: transfer entropy (TE), differential quantifier, and squared-coefficients quantifier based on an evolution map. The study is performed on the system of two stochastic Kuramoto oscillators within the framework of dynamical causal effects. The quantifiers are related to each other and to an asymptotic effect of the coupling on phase diffusion. Several novel findings are listed as follows: (i) for a non-synchronous regime and high enough noise levels, the TE rate multiplied by a certain characteristic time (called here reduced TE) equals twice an asymptotic effect of a directional coupling on phase diffusion; (ii) “information flow” expressed by the TE rate unboundedly rises with the coupling coefficient even in the domain of effective synchronization; (iii) in any effective synchronization regime, the reduced TE is equal to 1/8 n.u. in each direction for equal coupling coefficients and equal noise intensities, and it is in general a simple function of the ratio of noise intensities and the ratio of coupling coefficients.
Environmentally friendly regenerated cellulose films with improved dielectric properties via manipulating the hydrogen bonding network
Authors: Shi Shao-Cong , Chen Chao , Zhu Jin-Long , Li Yue , Meng Xin , Huang Hua-Dong , Li Zhong-Ming
Published: July 2021

Polymer dielectrics with a high energy density, an outstanding breakdown strength, and a low dielectric loss are currently in great demand in the field of film capacitors. Here, on the basis of fundamental understanding of dielectric relaxation in cellulose, environmentally friendly regenerated cellulose-based dielectrics were fabricated by manipulating their intrinsic hydrogen bonding network, in which hydroxyl groups of cellulose were reacted with epichlorohydrin (ECH) to simultaneously reduce the density of the intra- and intermolecular hydrogen bonding networks and the crystallinity for activating the movement of polar groups. As a result, when the molar ratio of ECH to glucose units of cellulose is 1:1, the regenerated cellulose-based dielectrics exhibited the highest dielectric constant of 9.7 at 103 Hz with the dielectric loss in an order of 10−2 and an energy density of 2.16 J/cm3 with a high charge–discharge efficiency of >85% at 200 MV/m. This methodology presented here provides a promising avenue for designing and improving the dielectric properties of cellulose-based dielectrics.
Generalized splay states in phase oscillator networks
Authors: Berner Rico , Yanchuk Serhiy , Maistrenko Yuri , Schöll Eckehard
Published: July 2021

Networks of coupled phase oscillators play an important role in the analysis of emergent collective phenomena. In this article, we introduce generalized m-splay states constituting a special subclass of phase-locked states with vanishing mth order parameter. Such states typically manifest incoherent dynamics, and they often create high-dimensional families of solutions (splay manifolds). For a general class of phase oscillator networks, we provide explicit linear stability conditions for splay states and exemplify our results with the well-known Kuramoto–Sakaguchi model. Importantly, our stability conditions are expressed in terms of just a few observables such as the order parameter or the trace of the Jacobian. As a result, these conditions are simple and applicable to networks of arbitrary size. We generalize our findings to phase oscillators with inertia and adaptively coupled phase oscillator models.
Deep surface modification with silicon improves the cycling stability of nickel-rich LiNi0.83Co0.06Mn0.11O2 cathode
Authors: Lv Fei , Zhang Yimin , Wu Mengtao , Gu Yuzong
Published: July 2021

Nickel-rich and cobalt-poor Li[Ni0.83Co0.06Mn0.11]O2 (NCM83) cathode is more effective than normal Li[Ni0.83Co0.11Mn0.06]O2 for high energy density lithium-ion battery applications. However, its capacity degradation caused by the structural instability and large phase transition resistance during cycling critically hinders the commercialization. Herein, we report that a deep surface modification of NCM83 with silicon can maximally balance the high conductivity and the good structural stability to improve its electrochemical performance and long cycling stability. The electrochemical results showed that the capacity retention of the resultant sample Si-NCM83 was remarkably increased at 0.1 C (210.3 mA h g−1) from 85.8% to 96.3% after 500 cycles compared with NCM83. The greatly improved cycle life of Si-NCM83 was attributed to the cycling stability achieved by the reduction of anisotropic volume change, microcracks from structural stress, and the uniform long rod-shaped primary particles, which lead to the acceleration of the diffusion of lithium-ions.
Regulation of absorption coefficients between multi-photon and free-carrier in PbTe films by deposition temperature
Authors: Cao Wentian , Wang Shuyun , Bai Qingwang , Guo Bin
Published: July 2021

We investigate the effects of deposition temperature on a crystal structure and electrical and optical properties of PbTe thin films sputtered on BaF2 (111). We observe that with the increase in deposition temperature, the grain size increases, and when it reaches 300 °C, the grain size reaches the maximum, and the preferred orientation begins to change. At 400 °C, the lattice mismatch rate decreases from 4.2% to 3.6% due to lattice contraction caused by reevaporation, and the conduction type changes from p-type dominated by a mismatch strain defect to n-type dominated by a Te vacancy. These changes lead to the interplay of various absorption mechanisms. We find that, in addition to the overall absorption coefficient curve significantly changing with deposition temperature, more importantly, the contribution of various internal absorption mechanisms to the below bandgap absorption spectrum does no longer synchronize. Instead, the contribution of an acoustic phonon to free-carrier absorption (FCA) decreases, while the relative contribution of optical phonon, impurity, two-photon absorption (2PA), and three-photon absorption (3PA) increases. This regulation effect reaches its maximum at 300 °C, which of various absorption mechanisms at 300 °C are 6.3, 11.6, 4.4, and 14.7 times higher than that at 20 °C corresponding to an optical phonon, impurity, 2PA, and 3PA processes, respectively. These results indicate that it should be possible to regulate the FCA, 2PA, and 3PA processes by changing the deposition temperature, thus making them suitable for applications in optoelectronic devices.
Introduction to Focus Issue: Recent advances in modeling complex systems: Theory and applications
Authors: Awrejcewicz Jan , Sanjuán Miguel A. F.
Published: July 2021

This is an introductory paper of the Focus Issue Recent advances in modeling complex systems: Theory and applications, where papers presenting new advances and insights into chaotic dynamics, fractional dynamics, complex oscillations, complex traffic dynamics, and complex networks, as well as their applications, are collected. All these different problems share common ideas and methods and provide new perspectives for further progress in the modeling of complex systems.
Enzymatic depolymerization of highly crystalline polyethylene terephthalate enabled in moist-solid reaction mixtures
Authors: Kaabel Sandra , Therien J. P. Daniel , Deschênes Catherine E. , Duncan Dustin , Friščić Tomislav , Auclair Karine
Published: July 2021

Significance

Although polyethylene terephthalate (PET) is the most recycled plastic, its recycling typically involves thermomechanical means, producing a plastic of lower quality that cannot be recycled again. In contrast, breaking PET down to its building blocks allows for repolymerization into high-quality PET. Chemical depolymerization of PET requires hazardous chemicals and conditions. Enzymes are environmentally benign, renewable catalysts that work under mild conditions. Several enzymes capable of depolymerizing low-crystallinity PET have been reported; however, efficient depolymerization of highly crystalline forms of PET typically found in consumer products has remained elusive. Here, we report that, in moist-solid reaction mixtures, the cutinase from
Humicola insolens
can efficiently hydrolyze highly crystalline PET to terephthalic acid with a 50% yield, without any amorphization or pretreatment of PET.
Combining CD47 blockade with trastuzumab eliminates HER2-positive breast cancer cells and overcomes trastuzumab tolerance
Authors: Upton Rosalynd , Banuelos Allison , Feng Dongdong , Biswas Tanuka , Kao Kevin , McKenna Kelly , Willingham Stephen , Ho Po Yi , Rosental Benyamin , Tal Michal Caspi , Raveh Tal , Volkmer Jens-Peter , Pegram Mark D. , Weissman Irving L.
Published: July 2021

Significance

This study demonstrates the efficacy of combining macrophage-checkpoint inhibition with tumor-specific antibodies for cancer immunotherapy. The combination of anti-CD47 (magrolimab) and anti-HER2 (trastuzumab) antibodies eliminated HER2+breast cancer cells with increased efficacy due to the enhancement of antibody-dependent cellular phagocytosis by macrophages, even when the cancer cells were tolerant to trastuzumab-induced antibody-dependent cellular cytotoxicity by natural killer cells. We believe these findings present a promising therapeutic approach for treating HER2+breast cancer patients whose tumors are either sensitive or resistant to trastuzumab treatment, as long as the cells harbor the HER2 trastuzumab-binding epitope. This study supports the notion that combining CD47 blockade with existing macrophage FcR-engaging tumor-specific antibodies may be an effective approach for treating a wide range of cancers.
When anti-corruption fails: the dynamics of procurement in contemporary South Africa
Authors: Gray Nomtha
Published: July 2021

Recent investigations into the phenomenon of state capture in South Africa have identified procurement as a central mechanism of rent generation for key actors. This article examines some of the ways in which anti-corruption measures failed, and argues that it will not be resolved by implementing more robust policies. Policies already conform to world-class standards, yet the way in which procurement is practised should be addressed more urgently. Practices that are reminiscent of apartheid-era levels of compliance have made it a function that prioritises ‘following orders’ above policy compliance, which undermines procurement’s ability to contribute to organisational effectiveness.
Tumor cells generate astrocyte-like cells that contribute to SHH-driven medulloblastoma relapse
Authors: Guo Duancheng , Wang Yuan , Cheng Yan , Liao Shengyou , Hu Jian , Du Fang , Xu Gang , Liu Yongqiang , Cai Kathy Q. , Cheung Martin , Wainwright Brandon J. , Lu Q. Richard , Zhao Yi , Yang Zeng-jie
Published: July 2021

Astrocytes, a major glial cell type in the brain, play a critical role in supporting the progression of medulloblastoma (MB), the most common malignant pediatric brain tumor. Through lineage tracing analyses and single-cell RNA sequencing, we demonstrate that astrocytes are predominantly derived from the transdifferentiation of tumor cells in relapsed MB (but not in primary MB), although MB cells are generally believed to be neuronal-lineage committed. Such transdifferentiation of MB cells relies on Sox9, a transcription factor critical for gliogenesis. Our studies further reveal that bone morphogenetic proteins (BMPs) stimulate the transdifferentiation of MB cells by inducing the phosphorylation of Sox9. Pharmacological inhibition of BMP signaling represses MB cell transdifferentiation into astrocytes and suppresses tumor relapse. Our studies establish the distinct cellular sources of astrocytes in primary and relapsed MB and provide an avenue to prevent and treat MB relapse by targeting tumor cell transdifferentiation.
Optoelectronic oscillator for 5G wireless networks and beyond
Authors: Zou Fang , Zou Lei , Yang Bo , Ma Qian , Zou Xihua , Zou Jim , Chen Siming , Milosevic Dusan , Cao Zizheng , Liu Huiyun
Published: July 2021

With the development of 5G wireless network and beyond, the wireless carrier frequency will definitely reach millimeter-wave (mm-wave) and even terahertz (THz). As one of the key elements in wireless networks, the local oscillator (LO) needs to operate at mm-wave and THz band with lower phase noise, which becomes a major challenge for commercial LOs. In this article, we investigate the recent developments of the electronic integrated circuit (EIC) oscillator and the optoelectronic oscillator (OEO), and especially investigate the prospect of OEO serving as a qualified LO in the 5G wireless network and beyond. Both the EIC oscillators and OEOs are investigated, including their basic theories of operation, representative techniques and some milestones in applications. Then, we compare the performances between the EIC oscillators and the OEOs in terms of frequency accuracy, phase noise, power consumption and cost. After describing the specific requirements of LO based on the standard of 5G and 6G wireless communication systems, we introduce an injection-locked OEO architecture which can be implemented to distribute and synchronize LOs. The OEO has better phase noise performance at high frequency, which is greatly desired for LO in 5G wireless network and beyond. Besides, the OEO provides an easy and low-loss method to distribute and synchronize mm-wave and THz LOs. Thanks to photonic integrated circuit development, the power consumption and cost of OEO reduce gradually. It is foreseeable that the integrated OEO with lower cost may have a promising prospect in the 5G wireless network and beyond.
Anisotropic (p, q)-equations with gradient dependent reaction
Authors: Papageorgiou Nikolaos S , Rădulescu Vicenţiu D , Repovš Dušan D
Published: July 2021

We consider a Dirichlet problem driven by the anisotropic (p, q)-Laplacian and a reaction with gradient dependence (convection). The presence of the gradient in the source term excludes from consideration a variational approach in dealing with the qualitative analysis of this problem with unbalanced growth. Using the frozen variable method and eventually a fixed point theorem, the main result of this paper establishes that the problem has a positive smooth solution.
EDP-convergence for nonlinear fast–slow reaction systems with detailed balance*
Authors: Mielke Alexander , Peletier Mark A , Stephan Artur
Published: July 2021

We consider nonlinear reaction systems satisfying mass-action kinetics with slow and fast reactions. It is known that the fast-reaction-rate limit can be described by an ODE with Lagrange multipliers and a set of nonlinear constraints that ask the fast reactions to be in equilibrium. Our aim is to study the limiting gradient structure which is available if the reaction system satisfies the detailed-balance condition. The gradient structure on the set of concentration vectors is given in terms of the relative Boltzmann entropy and a cosh-type dissipation potential. We show that a limiting or effective gradient structure can be rigorously derived via EDP-convergence, i.e. convergence in the sense of the energy-dissipation principle for gradient flows. In general, the effective entropy will no longer be of Boltzmann type and the reactions will no longer satisfy mass-action kinetics.
An anisotropic bouncing universe in non-local gravity
Authors: Kumar K. Sravan , Maheshwari Shubham , Mazumdar Anupam , Peng Jun
Published: July 2021

We show that it is possible to realize a cosmological bouncing solution in an anisotropic but homogeneous Bianchi-I background in a class of non-local, infinite derivative theories of gravity. We show that the anisotropic shear grows slower than in general relativity during the contraction phase, peaks to a finite value at the bounce point, and then decreases as the universe asymptotes towards isotropy and homogeneity, and ultimately to de Sitter. Along with a cosmological constant, the matter sector required to drive such a bounce is found to consist of three components — radiation, stiff matter and k-matter (whose energy density decays like the inverse square of the average scale factor). Generically, k-matter exerts anisotropic pressures. We will test the bouncing solution in local and non-local gravity and show that in the latter case it is possible to simultaneously satisfy positivity of energy density and, at least in the late time de Sitter phase, avoid the introduction of propagating ghost/tachyonic modes.
Spectral and photophysical modifications of porphyrins attached to core–shell nanoparticles. Theory and experiment
Authors: Kelm A , Ostapko J , Gajewska A , Sánchez-Iglesias A , Waluk J
Published: July 2021

Plasmonic nanostructures, of which gold nanoparticles are the most elementary example, owe their unique properties to localized surface plasmons (LSP), the modes of free electron oscillation. LSP alter significantly electromagnetic field in the nanostructure neighborhood (i.e., near-field), which can modify the electric dipole transition rates in organic emitters. This study aims at investigating the influence of Au@SiO2 core–shell nanoparticles on the photophysics of porphyrins covalently attached to the nanoparticles surface. Guided by theoretical predictions, three sets of gold nanoparticles of different sizes were coated with a silica layer of similar thickness. The outer silica surface was functionalized with either free-base meso-tetraphenylporphyrin or its zinc complex. Absorption and emission bands of porphyrin overlap in energy with a gold nanoparticle LSP resonance that provides the field enhancement. Silica separates the emitters from the gold surface, while the gold core size tunes the energy of the LSP resonance. The signatures of weak-coupling regime have been observed. Apart from modified emission profiles and shortened S1 lifetimes, Q band part intensity of the excitation spectra significantly increased with respect to the Soret band. The results were explained using classical transfer matrix simulations and electronic states kinetics, taking into account the photophysical properties of each chromophore. The calculations could reasonably well predict and explain the experimental outcomes. The discrepancies between the two were discussed.
Relativistic distorted wave approach to electron impact excitation of argon gas using a complex potential
Authors: Marucha Alex M , Kariuki Peter K , Okumu John , Singh Chandra S
Published: July 2021

In this study, we apply relativistic effects to excitation of the lowest lying resonance states of argon gas with inclusion of absorption, polarization and exchange effects to the electrostatic distortion potential to form an overall complex distortion potential. The atomic wave functions are constructed in the multi-configuration Dirac Fork approach by modifying the general-purpose relativistic atomic structure code GRASP for numerical procedures, while differential cross sections (DCS) and integral cross sections (ICS) have been obtained using our new code RDWBA1. Our results are compared with available experimental and theoretical results in literature. Present results from this study predict that use of a complex distortion potential in the relativistic approach to excitation of argon generally lowers integral and differential cross sections as impact energies of the incident electron increases, specifically beyond 50 eV, and that the energy dependent polarization potential adopted in this work plays a major role in improving shapes of cross-sections at near threshold impact energies up to around 30 eV, where available distorted-wave methods fail to give satisfactory results when compared to experiments.