Ruminant animals depend on cellulolytic ruminal bacteria to digest cellulose, but these bacteria cannot resist the low ruminal pH that modern feeding practices can create. Because the cellulolytic bacteria cannot grow on cellobiose at low pH, pH sensitivity is a general aspect of growth and not just a limitation of the cellulases per se. Acid-resistant ruminal bacteria have evolved the capacity to let their intracellular pH decrease, maintain a small pH gradient across the cell membrane, and prevent an intracellular accumulation of VFA anions. Cellulolytic bacteria cannot grow with a low intracellular pH, and an increase in pH gradient leads to anion toxicity. Prevotella ruminicola cannot digest native cellulose, but it grows at low pH and degrades the cellulose derivative, carboxymethylcellulose. The Prevotella ruminicola carboxymethylcellulase cannot bind to cellulose, but a recombinant enzyme having the Prevotella ruminicola catalytic domain and a binding domain from Thermomonspora fusca was able to bind and had cellulase activity that was at least 10-fold higher. Based on these results, gene reconstruction offers a means of converting Prevotella ruminicola into a ruminal bacterium that can digest cellulose at low pH.
Plasmonic nanoantennas offer new avenues to manipulate the propagation of light in materials due to their near field enhancement and ultrafast response time. Here we investigate the epsilon-near-zero (ENZ) response in an L-shaped nanoantenna structure under the phenomenon of plasmonic analog of enhancement in the index of refraction. Using a quantum mechanical approach, we analyze the modulation in the response of probe field and emergence of ENZ frequency region both in the linear and nonlinear plasmonic system. We also demonstrate the active tuning of ENZ frequency region in a nanoantenna structure by modulating the phase of control pulse. The analytical and 3D FDTD simulation results show a significant spectral shift in the ENZ modes. Our proposed method offers the possibility to design and control optical tunable ENZ response in plasmonic metasurfaces without the use of ENZ material. Such metasurfaces can be used in on-chip photonic integrated circuits, further localization of incident fields, slow light operations and various quantum technologies.
Satoshi Iihama, Yuya Koike, Shigemi Mizukami
et al.
Neuromorphic computing using spin waves is promising for high-speed nanoscale devices, but the realization of high performance has not yet been achieved. Here we show, using micromagnetic simulations and simplified theory with response functions, that spin-wave physical reservoir computing can achieve miniaturization down to nanoscales keeping high computational power comparable with other state-of-art systems. We also show the scaling of system sizes with the propagation speed of spin waves plays a key role to achieve high performance at nanoscales.
Andreas Gottscholl, Maximilian Wagenhöfer, Valentin Baianov
et al.
We present the very first demonstration of a maser utilizing silicon vacancies (VSi) within 4H silicon carbide (SiC). Leveraging an innovative feedback-loop technique, we elevate the resonator's quality factor, enabling maser operation even above room temperature. The SiC maser's broad linewidth showcases its potential as an exceptional preamplifier, displaying measured gain surpassing 10dB and simulations indicating potential amplification exceeding 30dB. By exploiting the relatively small zero-field splitting (ZFS) of VSi in SiC, the amplifier can be switched into an optically-pumped microwave photon absorber, reducing the resonator's mode temperature by 35 K below operating conditions. This breakthrough holds promise for quantum computing advancements and fundamental studies in cavity quantum electrodynamics. Our findings highlight SiC's transformative potential in revolutionizing contemporary microwave technologies.
Manoj Pandey, Dipendra Hamal, Bijaya Basnet
et al.
Solvent engineering offers fine control over the photovoltaic efficiency, film morphology, and crystallization quality of perovskite films and also enables to optimize light transmittance and absorbance in solar cell applications. In the present work, the band gap and reflectance were reduced through solvent engineering. We found that perovskite thin films produced using DMF (Dimethyl formamide) solvent had a band gap that was 0.24 eV less than those produced using IPA (Isopropyl Alcohol) solvent. Perovskite thin films produced using DMF solvent also exhibited considerably lower solar spectrum reflectance.
The transfer matrix formalism is widely used in modeling heat diffusion in layered structures.Due to an intrinsic numerical instability issue, which has not yet drawn enough attention to the heat transfer community,this formalism fails at high heating frequencies and/or in thick structures. Inspired by its success in modeling wave propagation, we develop a numerically-stable scattering matrix framework to model periodic heat diffusion in stratified solid media.As a concreate example, we apply this scattering matrix methodology to the three omega method.We first validate our framework using various well-known solutions.Next, we demonstrate the numerical stability of the framework using a configuration that resembles the three-dimensional stacked architecture for chip packing. Last, we propose synthetic experiments to exhibit, under certain circumstances, the merits of the scattering matrix formalism in extracting thermal properties.
Absorption spectroscopy is a widely used technique that permits the detection and characterization of gas species at low concentrations. We propose a sensing strategy combining the advantages of frequency modulation spectroscopy with the reduced noise properties accessible by squeezing the probe state. A homodyne detection scheme allows the simultaneous measurement of the absorption at multiple frequencies and is robust against dispersion across the absorption profile. We predict a significant enhancement of the signal-to-noise ratio that scales exponentially with the squeezing factor. An order of magnitude improvement beyond the standard quantum limit is possible with state-of-the-art squeezing levels facilitating high precision gas sensing.