Output Arm Research Articles

Engineering acyclovir-induced RNA nanodevices for reversible and tunable control of aptamer function

Small molecule-regulated RNA devices have the potential to modulate diverse aspects of cellular function, but the small molecules used to date have potential toxicities limiting their use in cells. Here we describe a method for creating drug-regulated RNA nanodevices (RNs) using acyclovir, a biologically compatible small molecule with minimal toxicity. Our modular approach involves a scaffold comprising a central F30 three-way junction, an integrated acyclovir aptamer on the input arm, and a variable effector-binding aptamer on the output arm. This design allows for the rapid engineering of acyclovir-regulated RNs, facilitating temporal, tunable, and reversible control of intracellular aptamers. We demonstrate the control of the Broccoli aptamer and the iron-responsive element (IRE) by acyclovir. Regulating the IRE with acyclovir enables precise control over iron-regulatory protein (IRP) sequestration, consequently promoting the inhibition of ferroptosis. Overall, the method described here provides a platform for transforming aptamers into acyclovir-controllable antagonists against physiologic target proteins.

Evolution of horn length and lifting strength in the Japanese rhinoceros beetle Trypoxylus dichotomus

What limits the size of nature's most extreme structures? For weapons like beetle horns, one possibility is a tradeoff associated with mechanical levers: as the output arm of the lever system-the beetle horn-gets longer, it also gets weaker. This "paradox of the weakening combatant" could offset reproductive advantages of additional increases in weapon size. However, in contemporary populations of most heavily weaponed species, males with the longest weapons also tend to be the strongest, presumably because selection drove the evolution of compensatory changes to these lever systems that ameliorated the force reductions of increased weapon size. Therefore, we test for biomechanical limits by reconstructing the stages of weapon evolution, exploring whether initial increases in weapon length first led to reductions in weapon force generation that were later ameliorated through the evolution of mechanisms of mechanical compensation. We describe phylogeographic relationships among populations of a rhinoceros beetle and show that the "pitchfork" shaped head horn likely increased in length independently in the northern and southern radiations of beetles. Both increases in horn length were associated with dramatic reductions to horn lifting strength-compelling evidence for the paradox of the weakening combatant-and these initial reductions to horn strength were later ameliorated in some populations through reductions to horn length or through increases in head height (the input arm for the horn lever system). Our results reveal an exciting geographic mosaic of weapon size, weapon force, and mechanical compensation, shedding light on larger questions pertaining to the evolution of extreme structures.

Waveguide demultiplexer based on Helmholtz-resonator mediated extraordinary acoustic transmission

The design of an acoustic demultiplexer based on in-line Helmholtz resonators is demonstrated analytically via a modified transfer matrix method and computationally through finite element simulations. The modeled system consists of a single input waveguide that splits in a Y-configuration into two output waveguides. Each output arm has a single tuned Helmholtz resonator embedded in-line along the length of the guide. The Helmholtz resonators in each arm consist of a single cavity with two necks—one directed towards the input and output sides of the guide. The phenomenon of extraordinary acoustic transmission results in near perfect transmission of sound along each output arm in a small frequency interval about the Helmholtz resonant frequency. The demultiplexed frequencies are determined by the physical dimensions of the Helmholtz resonator. Using a single Helmholtz resonator in each output arm means that the system is more compact compared to other proposed schemes using either side-loaded Helmholtz resonators or stubs.

Passively phase-locked Er:fiber source of single-cycle pulses in the near infrared with electro-optic timing modulation for field-resolved electron control.

A single-cycle light source in the near infrared is demonstrated enabling sensitive applications of ultrafast optical field control of electronic transport. The compact Er:fiber system generates passively phase-locked pulses with broadband spectra covering 150 THz to 350 THz at a duration of 4.2 fs and 40 MHz repetition rate. A second output arm is equipped with an electro-optic modulator (EOM) that switches the arrival time of the pulses by 700 ps at arbitrary frequencies up to 20 MHz, enabling timing modulation of the pump pulse without changing the average intensity. As a benchmark demonstration, we investigate the carrier relaxation dynamics in low-temperature-grown InGaAs (LT-InGaAs) using quantum interference currents (QuICs).

Acoustic waveguide demultiplexer based on Fano resonance: Experiment and simulation

A compact acoustic waveguide demultiplexer configuration is studied via finite-element numerical modeling and audio frequency experiments. The demultiplexer consists of a Y-shaped waveguide with a single input and two outputs. The narrow transmission bands created by stubs side-loaded on each output arm lead to selective transmission of certain frequencies. The experimental work characterizes the broadband response along each output arm by using an impulse response method. Finite-element numerical simulations are conducted using COMSOL. The results of the experiment and the simulation are compared to an existing analytic theory.

Lifetime-resolved photon-correlation Fourier spectroscopy.

The excited state population of single solid-state emitters is subjected to energy fluctuations around the equilibrium driven by the bath and relaxation through the emission of phonons or photons. Simultaneous measurement of the associated spectral dynamics requires a technique with a high spectral and temporal resolution with an additionally high temporal dynamic range. We propose a pulsed excitation-laser analog of photon-correlation Fourier spectroscopy (PCFS), which extracts the linewidth and spectral diffusion dynamics along the emission lifetime trajectory of the emitter, effectively discriminating spectral dynamics from relaxation and bath fluctuations. This lifetime-resolved PCFS correlates photon-pairs at the output arm of a Michelson interferometer in both their time-delay between laser-excitation and photon-detection T and the time-delay between two photons τ. We propose the utility of the technique for systems with changing relative contributions to the emission from multiple states, for example, quantum emitters exhibiting phonon-mediated exchange between different fine-structure states.

Convergence Rates for the Quantum Central Limit Theorem

Various quantum analogues of the central limit theorem, which is one of the cornerstones of probability theory, are known in the literature. One such analogue, due to Cushen and Hudson, is of particular relevance for quantum optics. It implies that the state in any single output arm of an n-splitter, which is fed with n copies of a centred state rho with finite second moments, converges to the Gaussian state with the same first and second moments as rho . Here we exploit the phase space formalism to carry out a refined analysis of the rate of convergence in this quantum central limit theorem. For instance, we prove that the convergence takes place at a rate mathcal {O}left( n^{-1/2}right) in the Hilbert–Schmidt norm whenever the third moments of rho are finite. Trace norm or relative entropy bounds can be obtained by leveraging the energy boundedness of the state. Via analytical and numerical examples we show that our results are tight in many respects. An extension of our proof techniques to the non-i.i.d. setting is used to analyse a new model of a lossy optical fibre, where a given m-mode state enters a cascade of n beam splitters of equal transmissivities lambda ^{1/n} fed with an arbitrary (but fixed) environment state. Assuming that the latter has finite third moments, and ignoring unitaries, we show that the effective channel converges in diamond norm to a simple thermal attenuator, with a rate mathcal {O}Big (n^{-frac{1}{2(m+1)}}Big ). This allows us to establish bounds on the classical and quantum capacities of the cascade channel. Along the way, we derive several results that may be of independent interest. For example, we prove that any quantum characteristic function chi _rho is uniformly bounded by some eta _rho <1 outside of any neighbourhood of the origin; also, eta _rho can be made to depend only on the energy of the state rho .

Conceptual design of magnonic majority-logic gate based on channeling of spin waves in domain walls

A three-input majority gate, which operates on the basis of majority decisions, can function as multifunctional Boolean logic gates. Here, we report a micromagnetic simulation study of a specially devised magnonic majority-logic gate that utilizes channeling of spin waves into narrow domain walls. Our model system is a four-armed cross structure where low-energy spin waves are guided and channeled along Néel-type domain walls and then interact with a single magnetic vortex positioned at the cross-point. After exciting spin waves simultaneously from the ends of three individual arms where input binary digits are encoded using spin-wave phase information, the phases of spin waves passing through the cross-point (after being scattered from the vortex) are measured as output binary digits at the end of the remaining single output arm. Consequently, the majority of the input variables determines the output signal, which is a clear sign of a majority gate. Furthermore, by setting a control input, our proposed single structure can perform multiple operations of AND-, OR-, NAND-, and NOR-gates. Finally, the gate structure and channeling spin waves into domain walls/their interaction with a vortex core have the additional merits of being free of the Joule heating typically encountered in conventional electronic devices and of having long coherence lengths.

Full Band Compact Power Arm Subsystem With High Directive Sample

An output arm is the first subsystem in the microwave components chain connected immediately after the power amplifier. These arms are responsible for transferring the signal from the output port of the power amplifier to the standard line of the system. The second objective is to obtain directive samples for both forward and backward signals. The typical design process for such a subsystem is carried out through the design of separate components, independently. This limits the achievable performance of the entire system and introduces excessive losses at intermediate flanges. In this work, we present a novel approach to design such a subsystem using a global optimization procedure. Specifically, we address both compactness and full-band operation of output arms deployed in radar applications. Analysis and design of each component in the proposed subsystem are illustrated. The presented subsystem achieves a deep matching level of 19 dB within an overall length below $2\lambda _{g}$ . Moreover, the directive sample obtained through the presented design has an ultra-flat response of 20 dB ± 0.5 dB over the entire band of operation, while the directivity of the samples exceeds 18 dB. The measured results of the fabricated prototype have an excellent agreement with the simulations.

The Neuropeptide Galanin Is Required for Homeostatic Rebound Sleep following Increased Neuronal Activity

Sleep pressure increases during wake and dissipates during sleep, but the molecules and neurons that measure homeostatic sleep pressure remain poorly understood. We present a pharmacological assay in larval zebrafish that generates short-term increases in wakefulness followed by sustained rebound sleep after washout. The intensity of global neuronal activity during drug-induced wakefulness predicted the amount of subsequent rebound sleep. Whole-brain mapping with the neuronal activity marker phosphorylated extracellular signal-regulated kinase (pERK) identified preoptic Galanin (Galn)-expressing neurons as selectively active during rebound sleep, and the relative induction of galn transcripts was predictive of total rebound sleep time. Galn is required for sleep homeostasis, as galn mutants almost completely lacked rebound sleep following both pharmacologically induced neuronal activity and physical sleep deprivation. These results suggest that Galn plays a key role in responding to sleep pressure signals derived from neuronal activity and functions as an output arm of the vertebrate sleep homeostat.

Modified Increased-Level Model Predictive Control Methods With Reduced Computation Load for Modular Multilevel Converter

It is considerable to reduce the computation load while keeping a good total harmonic distortion (THD) performance for the modular multilevel converter (MMC) with model predictive control (MPC). In this paper, the discrete-time mathematical model of the MMC is derived and the output voltage ripples of the cascaded submodules (SMs) are analyzed in detail. Accordingly, a modified increased-level MPC method A (IL-MPC-A) is proposed with 2 N + 1 ac-side output voltage levels. The computation load is significantly reduced without losing the harmonic circulating currents suppression and capacitor voltage ripples compensation capabilities. In this method, the cost function minimization step and capacitor voltage sorting algorithm are combined to determine the optimal control option. In addition, to avoid the selection of weighting factors and further reduce the computation load as the increasing of the SM number, another modified IL-MPC-B is proposed by directly calculating the optimal ac-side output voltage level and arm summation voltage according to the discrete-time mathematical model. As a result, the ac-side output current and circulating current controls are decoupled. Furthermore, the capacitor voltages are balanced with a proposed control scheme by adjusting the circulating current reference. The effectiveness of the proposed MPC methods is verified by simulation and experimental results.

Differential regulation of the Drosophila sleep homeostat by circadian and arousal inputs.

One output arm of the sleep homeostat in Drosophila appears to be a group of neurons with projections to the dorsal fan-shaped body (dFB neurons) of the central complex in the brain. However, neurons that regulate the sleep homeostat remain poorly understood. Using neurogenetic approaches combined with Ca2+ imaging, we characterized synaptic connections between dFB neurons and distinct sets of upstream sleep-regulatory neurons. One group of the sleep-promoting upstream neurons is a set of circadian pacemaker neurons that activates dFB neurons via direct glutaminergic excitatory synaptic connections. Opposing this population, a group of arousal-promoting neurons downregulates dFB axonal output with dopamine. Co-activating these two inputs leads to frequent shifts between sleep and wake states. We also show that dFB neurons release the neurotransmitter GABA and inhibit octopaminergic arousal neurons. We propose that dFB neurons integrate synaptic inputs from distinct sets of upstream sleep-promoting circadian clock neurons, and arousal neurons.

Fault Diagnosis and System Reconfiguration Strategy of Single-phase Three Level Neutral-Point-Clamped Cascaded Inverter

This paper presents a fault diagnosis method and system reconfiguration strategy of a three-level neutral-point-clamped cascaded inverter (3L-NPC-CI) to enhance the reliability of power supply in an electrified railway. First, the neural network (NN) is employed to perform an open-circuit fault diagnosis and identify fault switches. Then, system reconfiguration strategy is proposed to perform a single-phase 3L-NPC-CI reconfiguration. Through the analysis of the operation status of 3L-NPC, there are eight fault modes in a single-bridge arm, including the single-switch fault and double-switch fault. By the feature analysis for the output arm voltage harmonic of normal and eight fault modes, seven harmonic parameters are selected as fault feature vectors. Meanwhile, a three-layer NN is constructed, and the seven feature vectors are the input layer of the NN. By training algorithm, the fault switches location can be identified accurately about one modulation period. Then, the fault module is bypassed and the 3L-NPC-CI system is stable by reconfiguring the modulation strategy of other normal modular. Simulation and experimental results are given to validate the proposed fault diagnosis and system reconfiguration strategy. The proposed method is able to improve robustness and reliability of 3L-NPC-CI in the traction power supply system.

Design, Preparation, and Performance of a Planar Ignitor Inserted With PyroMEMS Safe and Arm Device

A planar ignitor-based on low temperature co-fired ceramic (LTCC) and pyrotechnical micro electro mechanical system (PyroMEMS) technologies was designed and prepared in this paper. The planar ignitor is mainly composed of output charge layer, silicon safe and arm (Si-S&A) layer, and LTCC circuit base. Si/Pb3O4, C6H2(NO2)3OK/KClO4, and B/KNO3 were selected as ignition charge, gas charge, and transfer charge, respectively. The ignition circuit and main structure of the planar igniter were made by the LTCC process. Si-S&A was etched from monocrystalline silicon, which does not need environmental force to disarm. Preparation process of main components of planar ignitor that is suitable for mass production was introduced in detail. Simulation of PyroMEMS S&A actuation based on pendulum method was performed to save time for proof test. Finally, experimental verification on PyroMEMS S&A actuation and combustion propagation of B/KNO3 transfer charge were completed successfully. Results show that the idea of a planar ignitor inserted with PyroMEMS S&A device is feasible. [2018-0075]

A Wake-Promoting Circadian Output Circuit in Drosophila

Circadian clocks play conserved roles in gating sleep and wake states throughout the day-night cycle [1-5]. In the fruit fly Drosophila melanogaster, DN1p clock neurons have been reported to play both wake- and sleep-promoting roles [6-11], suggesting a complex coupling of DN1p neurons to downstream sleep and arousal centers. However, the circuit logic by which DN1p neurons modulate sleep remains poorly understood. Here, we show that DN1p neurons can be divided into two morphologically distinct subsets. Projections from one subset surround the pars intercerebralis, a previously defined circadian output region [12]. In contrast, the second subsetalso sends presynaptic termini to a visual processing center, the anterior optic tubercle (AOTU) [13]. Within the AOTU, we find that DN1p neurons inhibit a class of tubercular-bulbar (TuBu) neurons that act to promote consolidated sleep. These TuBu neurons in turn form synaptic connections with R neurons of the ellipsoid body, a region linked to visual feature detection, locomotion, spatial memory, and sleep homeostasis [14-17]. Our results define a second output arm from DN1p neurons and suggest a role for TuBu neurons as regulators of sleep drive.

Electro-mechanical control of an on-chip optical beam splitter containing an embedded quantum emitter.

We demonstrate electro-mechanical control of an on-chip GaAs optical beam splitter containing a quantum dot single-photon source. The beam splitter consists of two nanobeam waveguides, which form a directional coupler (DC). The splitting ratio of the DC is controlled by varying the out-of-plane separation of the two waveguides using electromechanical actuation. We reversibly tune the beam splitter between an initial state, with emission into both output arms, and a final state with photons emitted into a single output arm. The device represents a compact and scalable tuning approach for use in III-V semiconductor integrated quantum optical circuits.

The establishment and simulation of bidirectional Cockcroft-Walton circuit model

PurposeThe purpose of this paper is to improve the stability of high voltage DC power supply and reduce the ripple.Design/methodology/approachThe study was conducted using the simulation analysis model and numerical calculation.FindingsBy increasing the output arm capacitance, the expression of ripple and times of the output arm capacitance and the auxiliary arm capacitance is derived. The output ripple is determined by the value of the output arm capacitance. Finally, the correctness of the method and the formula are verified using circuit simulation.Originality valueThis paper presents a method to improve the power supply stability.

Design of an integrated multi-arm power splitter using photonic crystal waveguide

This paper proposes a novel design of an integrated multi-arm power splitter based on photonic crystal waveguides. A 1×5 power splitter is proposed by introducing line defects to form a one input waveguide arm and five output waveguide arms. The plane wave expansion method (PWE) is used to investigate the dispersion characteristics of the light coupling between the guided modes in the photonic band gap (PBG) from 0.037 ω/2πc to 0.095 ω/2πc frequency range. Using Finite-Difference Time Domain (FDTD) method, we calculated the power splitting across each output arm; 52.2% in arm C, 16.9% in arm D, 14.6% in arm E, 12.1% in arm A and 3.4% in arm B. The total observed transmission efficiency of the splitter is 99.2%. Further, the time response of electric field along the Y direction (Ey) which is perpendicular to the X-Z plane is studied. The output arms C, E, D and B show beam shaped envelope response while the remaining output arm A exhibit negligible variation with time. The compact and low cost proposed design contributes to the state of art progress in the field of photonics integrated circuits (PICs) technology where the power splitter plays a prominent role of splitting optical power between all the optical elements integrated in the chip.

The Establishment and Analysis of Bidirectional Cockcroft-Walton Circuit Model

High voltage DC power supply is very important in laser and high precision instruments, so the stability of high voltage DC power supply has an affect on the stability of laser and equipment. The voltage doubling rectifier circuit is the core component of the high voltage generator, so it is very important to study the stability of the voltage doubling rectifier circuit. Through the study of bidirectional rectifier circuit, double voltage rectifier circuit produces an output ripple and response time is superior than the basic voltage rectifier circuit. At the same time to study the bidirectional rectifier circuit is optimized, the capacity of the output arm greatly increases which leads to reduction in the output ripple, as the capacity reaches large enough value the output ripple approaches zero. Thus, greatly increasing the circuit in steady state time.

Common evolutionary trends underlie the four-bar linkage systems of sunfish and mantis shrimp.

Comparative biomechanics offers an opportunity to explore the evolution of disparate biological systems that share common underlying mechanics. Four-bar linkage modeling has been applied to various biological systems such as fish jaws and crustacean appendages to explore the relationship between biomechanics and evolutionary diversification. Mechanical sensitivity states that the functional output of a mechanical system will show differential sensitivity to changes in specific morphological components. We document similar patterns of mechanical sensitivity in two disparate four-bar systems from different phyla: the opercular four-bar system in centrarchid fishes and the raptorial appendage of stomatopods. We built dynamic linkage models of 19 centrarchid and 36 stomatopod species and used phylogenetic generalized least squares regression (PGLS) to compare evolutionary shifts in linkage morphology and mechanical outputs derived from the models. In both systems, the kinematics of the four-bar mechanism show significant evolutionary correlation with the output link, while travel distance of the output arm is correlated with the coupler link. This common evolutionary pattern seen in both fish and crustacean taxa is a potential consequence of the mechanical principles underlying four-bar systems. Our results illustrate the potential influence of physical principles on morphological evolution across biological systems with different structures, behaviors, and ecologies.