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POSA for fast, amplified and multiplexed protein imaging
Continuous nursing symptom management in cancer chemotherapy patients using deep learning
A transparency statement improves trust in community-police interactions
Enhancement of power quality in grid-connected systems using a predictive direct power controlled based PV-interfaced with multilevel inverter shunt active power filter
Abstract The integration of Nonlinear Loads (NLs) in industrial, commercial and residential settings over the past two decades has significantly worsened power quality issues in modern electrical distribution networks. In today’s modern era, the growing use of sensitive and expensive electronic devices makes it crucial to ensure power quality for the reliable and secure functioning of the power system. Shunt Active Power Filters (SAPF) are necessary to prevent current distortions caused by NLs from entering the grid. Otherwise, system effectiveness and power transmission capabilities would be diminished. In this work, we introduce a novel Predictive Direct Power Control (PDPC) strategy incorporating generating reference signals for SAPF model of a Three-level (3 L) Neutral-Point Clamped (NPC) inverter. This innovative system serves as a SAPF, specifically designed to attenuate the harmonics emerging from abrupt increments in NLs. Moreover, it proactively addresses the challenge of reactive power within distribution systems. Utilizing an Enhanced Incremental Conductance (EINC) Maximum Power Point Tracking (MPPT) algorithm, the Photovoltaic (PV) module effectively optimizes power extraction, thereby augmenting the efficiency of the SAPF integration. This system is adept at satisfying the reactive power demands of the load by mitigating harmonics induced by the NLs while concurrently supplying active power harnessed from the PV arrays. The incorporation of the Adaptive Neuro-Fuzzy Inference System (ANFIS) algorithm facilitates the stabilization of the DC link voltage, further contributing to the system’s capability to meet reactive power requirements and elevate grid Power Quality (PQ) through the elimination of harmonics. The proposed strategy effectively reduces harmonics and maintains stable DC link voltage in variable linear and NLs load conditions. This system has been systematically designed, simulated, and experimentally validated, with results across various phases demonstrating its superior performance and enhanced efficiency in improving power quality.
Approach to improving the energy efficiency of thermoelectric coolers for IR detectors
The research is aimed at approaches to increasing the efficiency of thermoelectric coolers (TECs) for IR detectors and the development of experimental methods and tools for their implementation. One way is to optimize Bi2Te3-based materials by using inhomogeneous materials. Another way is to optimize the module design taking into account the electrical and thermal resistances of the contacts in the module, which reduce the coefficient of performance (COP). A new numerical method based on the optimal control theory is proposed for designing modules in the maximum COP mode. The results of the COP calculation prove that reducing the electrical contact resistance is the predominant factor for improving the efficiency of modules for IR detectors. The COP of coolers increases by 1.5–2.5 times compared to commercial modules if the contact resistance is brought closer to the minimum value of 10−7 Ω cm2. The use of inhomogeneous thermoelements and insulating plates made of aluminum nitride instead of alumina ceramics provides an additional increase in COP by 10% and 20%, respectively. To control the contact resistance, an improved probe method of measuring is proposed. Computer simulation is applied to estimate the uncertainty of contact resistance measuring by this method. It is proven that the uncertainty does not exceed 2%.
Antibiotic-mediated microbial community restructuring is dictated by variability in antibiotic-induced lysis rates and population interactions
Research on the extension of respiratory interaction modalities in virtual reality technology and innovative methods for healing anxiety disorders
Microparticle enrichment and steering via frequency-controlled acoustic bubble array
Manipulation of microscopic objects plays an essential role in broad applications. Microparticle enrichment and steering in microfluidic channels have been widely used in cell sorting and bio-analysis. However, there still lacks a method satisfying the requirements of good biocompatibility and alternative functions. Here, we propose an efficient method to achieve microparticle enrichment and steering via frequency-controlled acoustic bubble array. An aligned oscillating bubble array trapped by the side openings has been employed. The enrichment and steering direction of the target microparticles can be switched conveniently by altering the excitation frequency. Both experimental investigations and numerical modeling have been conducted, confirming the correctness and robustness of the method. The introduced mechanisms and methods pave the way for optimized cytometer sorting and biomedical analysis.
Urinary extracellular vesicle N-glycomics identifies diagnostic glycosignatures for bladder cancer
Diurnal variations in gait parameters among older adults with early-stage knee osteoarthritis: insights from wearable sensor technology
Investigation of microwave generation modes of nonlinear transmission lines based on microwave and low-frequency ferrites
A comprehensive analysis of the physical processes occurring in high-voltage nonlinear ferrite transmission lines in the microwave generation mode is presented. The nonlinear lines of the coaxial type, based on the microwave ferrite rings with different combinations of the magnetic parameters and hysteresis loop shapes, have been investigated for this purpose. A complex comparative analysis of the dependence of microwave generation modes on the magnetic properties, the length of the ferrite ring assembly, and the magnitude of the external bias field enables the processes observed in the nonlinear ferrite lines to be related to the properties of the spin waves. The proposed new approaches make it possible to associate, in the most complete and harmonious way the specific manifestation of the ferrite properties under the condition of ferromagnetic resonance in the oscillation modulation mode, with the classical statements of the theory of ferrites that refer to the relaxation processes involved in the propagation mode of powerful microwave (high alternating magnetic fields). The microwave generation modes observed for the first time and a detailed analysis of their efficient implementation are discussed. In addition, a promising frequency analysis based on the wavelet transform is proposed. The experimental data obtained indicate that microwaves can be generated in the absence of an external biasing field. The effect of secondary modulation with a frequency ∼10 times that of the main oscillations also was discussed. The findings of the study have a great potential as a basis for a wide range of further research and may, therefore, be of interest to researchers engaged in a variety of fields.
Xenon plasma focused ion beam lamella fabrication on high-pressure frozen specimens for structural cell biology
Abstract Cryo focused ion beam lamella preparation is a potent tool for in situ structural biology, enabling the study of macromolecules in their native cellular environments. However, throughput is currently limited, especially for thicker, more biologically complex samples. We describe how xenon plasma focused ion beam milling can be used for routine bulk milling of thicker, high-pressure frozen samples. We demonstrate lamellae preparation with a high success rate on these samples and determine a 4.0 Å structure of the Escherichia coli ribosome on these lamellae using sub volume averaging. We determine the effects on sample integrity of increased ion currents up to 60 nA during bulk milling of thicker planar samples, showing no measurable damage to macromolecules beyond an amorphous layer on the backside of the lamellae. The use of xenon results in substantial structural damage to particles up to approximately 30 nm in depth from the milled surfaces, and the effects of damage become negligibly small by 45 nm. Our results outline how the use of high currents using xenon plasma focused ion beam milling may be integrated into FIB milling regimes for preparing thin lamellae for high-resolution in situ structural biology.
Biomarkers of cell cycle arrest, microcirculation dysfunction, and inflammation in the prediction of SA-AKI
Thermophysical property measurement of GaN/SiC, GaN/AlN, and AlN/SiC epitaxial wafers using multi-frequency/spot-size time-domain thermoreflectance
Gallium nitride (GaN)-based high electron mobility transistors (HEMTs) are essential components in modern radio frequency power amplifiers. In order to improve both the device electrical and thermal performance (e.g., higher current density operation and better heat dissipation), researchers are introducing AlN into the GaN HEMT structure. The knowledge of thermal properties of the constituent layers, substrates, and interfaces is crucial for designing and optimizing GaN HEMTs that incorporate AlN into the device structure as the barrier layer, buffer layer, and/or the substrate material. This study employs a multi-frequency/spot-size time-domain thermoreflectance approach to measure the anisotropic thermal conductivity of (i) AlN and GaN epitaxial films, (ii) AlN and SiC substrates, and (iii) the thermal boundary conductance for GaN/AlN, AlN/SiC, and GaN/SiC interfaces (as a function of temperature) by characterizing GaN-on-SiC, GaN-on-AlN, and AlN-on-SiC epitaxial wafers. The thermal conductivity of both AlN and GaN films exhibits an anisotropy ratio of ∼1.3, where the in-plane thermal conductivity of a ∼1.35 μm thick high quality GaN layer (∼223 W m−1 K−1) is comparable to that of bulk GaN. A ∼1 μm thick AlN film grown by metalorganic chemical vapor deposition possesses a higher thermal conductivity than a thicker (∼1.4 μm) GaN film. The thermal boundary conductance values for a GaN/AlN interface (∼490 MW m-2 K−1) and AlN/SiC interface (∼470 MW m−2 K−1) are found to be higher than that of a GaN/SiC interface (∼305 MW m−2 K−1). This work provides thermophysical property data that are essential for optimizing the thermal design of AlN-incorporated GaN HEMT devices.
Economics of AI and human task sharing for decision making in screening mammography
An interpretable machine learning-assisted diagnostic model for Kawasaki disease in children
Phonon amplification via magnetoelastic Klein scattering
Materials exhibit various wave-like excitations, among which phonons (lattice vibrations) and magnons (oscillations in ferromagnetic ordering) hold significant promise for future nanoscale technologies. Exploring the interaction between these excitations may pave the way for innovative devices that leverage their complementary strengths. This article presents a setup designed to amplify an incoming phononic current, potentially enhancing the phonon lifetime. The setup consists of a non-magnetic and ferromagnetic insulator. The ferromagnet is polarized opposite to the external magnetic field with spin–orbit torque, which allows for negative-energy magnons. Phonons that are incoming from the non-magnetic side will interact with the negative-energy magnons via magnetoelastic coupling. The reflected phonon will increase in amplitude as a result of energy conservation. This interaction between negative-energy magnons and phonons is an example of Klein scattering. This work opens new avenues for the development of advanced devices that capitalize on the combined properties of phonons and magnons.
Fractional charging of electronically open molecules: An explicit projection operator approach
We introduce an approach to describe fractional charging of molecules interacting non-covalently with their environment. The formalism is based on dividing the full orbital space into orbitals localized to the molecule and orbitals localized to the environment. This enables a separation of the full electronic Hamiltonian into terms referencing only molecule, environment, or interaction terms. The interaction terms are divided into particle-conserving interactions and particle-non-conserving (particle-breaking) interactions. The particle-conserving interactions are dominant and may be included using standard embedding schemes. The particle-breaking terms are responsible for inducing fractional charging, and we show that the local orbital space approach provides a convenient framework for different types of perturbative treatments. In the local orbital basis, we generate a basis of many-electron states for the composite system, in which a specific molecular charge may label each state. This basis is used to construct a projection operator acting on the Liouville–von Neumann equation for the composite system to yield an equation for the reduced density matrix for the molecule. The diagonal elements of the reduced density matrix represent populations of different molecular charge states and determine the fractional charging. The projected Liouville–von Neumann equation is the starting point for two perturbative treatments: damped response theory and Redfield theory. The damped response framework introduces energy broadening of electronic states. Phenomenological broadening is also introduced into the Redfield equation. We illustrate the presented formalism by considering benzene physisorbed on a finite graphene sheet as a toy model.