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Valley Hall topological photonic crystals, inspired by topological insulators in condensed matter physics, have provided a promising solution to control the flow of light. Recently, the dynamic manipulation property of topological photonic crystals has been widely studied. Here, we propose a novel solution for programmable valley photonic crystals, called field programmable topological edge array (FPTEA), based on the field reorientation property of nematic liquid crystals and robust valley-protected edge modes. FPTEA is composed of an array of graphene-like lattices with C3 symmetry, in which the birefringence of liquid crystal is larger than 0.5105. Due to the dielectric anisotropy of liquid crystals being sensitive to external fields such as light, heat, electric, and magnetic fields, each lattice is tunable, and the topological propagation routes and even the lattice parameters can be dynamically changed while changing the distribution of external fields. We numerically demonstrate three methods of composing an FPTEA device to design arbitrary passive optical devices by electric driving, thermal inducing, or UV writing. These results show the great application potential of liquid crystals in topological photonic crystals, and enrich the design of programmable integrated topological devices with broad working bandwidth ranging from microwave to visible light.

Free-space optical (FSO) communication has attracted extensive attention in recent years. To maintain a reliable FSO link, two main issues need to be addressed: beam drift and vibration. In this paper, we demonstrate a non-mechanical self-alignment system based on a cascaded liquid crystal optical antenna, in which a frequency decoupled hybrid integration Kalman filter (FDHI-KF) method is proposed to achieve predictive beam drift tracking and vibration mitigation. By leveraging the integrated control on our lab-made liquid crystal phase modulation devices, and implementing the adaptive algorithm on a heterogeneous field programmable gate array (FPGA), this system is capable of realizing precise self-alignment without any moving parts. Experiments are conducted to verify its performance in practical applications. We envision it to set a benchmark for future liquid crystal non-mechanical beam-steering systems in FSO communications.

To implement a liquid crystal optical phased array (LC-OPA) on a practical free-space laser communication terminal, there are two essential parameters: insertion loss and the closed-loop bandwidth required to meet the dynamic linking condition of the acquisition-tracking-pointing sub-system. Real-time hardware platforms and deflection efficiency optimization algorithms have been suggested since the invention of LC-OPA. In this paper, the so-called ZYNQ platform, a field-programmable-gate-array-based heterogeneous system-on-chip (SoC), is utilized to keep real-time response and accelerate data generation, such as beam steering, beamforming, beam enhancement, etc. In addition, a novel, to the best of our knowledge, optimization algorithm is proposed on the concept of dimension reduction of the number of objective variables. After deploying on this heterogeneous SoC platform, numerical simulations and experimental results both verify that, compared to the conventional PC-based system, the integrated SoC platform offers 15.8 times faster iterative speed, a rapid convergence rate, and excellent robustness, yet with less usage of power, physical size, and monetary cost. The efficiency enhancement process costs only a few seconds at any angle, laying the foundation for practical in-line applications.

Carotenoids are unsaturated compounds with terpene groups. Among them, astaxanthin has strong antioxidant properties. It is widely used in aquaculture, food, medicine, and cosmetics with a broad market prospect.

Transcriptional downregulation is widely used for metabolic flux control. Here

Antibiotics are the most powerful weapon against bacterial infectious diseases in aquaculture. However, the indiscriminate usage of antibiotics often culminates in the emerging development of antibiotic-resistant bacteria, making it imperative to search for novel types of antimicrobial agents. This study investigated the antibacterial and antivirulence effects of vanillic acid (VA) against the fish pathogen, Vibrio alginolyticus. We showed that VA had a good anti-Vibrio activity with minimal inhibitory concentration (MIC) of 1.0 mg/ml. In addition, VA wielded its antibacterial action in a dose-/time-dependent manner by causing cell membrane damage and increasing membrane permeability, which is evidenced by increasing the conductivity and malondialdehyde content in the treated cell cultures and the scanning electron microscopy images. Furthermore, VA significantly reduced the biofilm-forming capability, mobility and exotoxin production (protease and exopolysaccharide) and downregulation of the expression of biofilm- and virulence-associated genes (sypG, fliS, fliK, lafA, lafK, asp and luxR) was seen in the V. alginolyticus that exposed to VA at subinhibitory concentrations. Overall, our findings suggested that VA may be of interest for treating V. alginolyticus-associated infections in aquaculture.

In this study, a novel liquid crystal (LC) stackable optical phased array (SOPA) for fine tracking with fast and precise beam steering is proposed. The SOPA was composed of multiple layers of sliced phase shifters (SPSs). Each SPS had two parts for loading different voltages to form programmable phase steps. All LC materials were compatible with this architecture, including blue-phase, polymer network, and ferroelectric LCs. To verify and evaluate the properties of this SOPA scheme, a three-layered SOPA prototype was designed and fabricated according to the standard processing of LC devices. A couple of steering experiments, with steering angles ranging from -100 to 100 μ rad in a step of 10 μ rad, were performed. The steering efficiency recorded in all the experiments exceeded 90%. All the measured switching time of angle-to-angle were less than 10 ms. Herein, the fastest switching time reported was only 1.52 ms.

Focusing on the coherent optics of phased array, a dynamic theoretical model is built to analyse the process of laser beam steering using the device of liquid crystal optical phased array. Based on the dynamics of electrical field induced liquid crystal molecule rotation and the mechanism of phased control non-mechanical steering, switching time is redefined according to two curves representing receiving power on the current direction and targeting direction. Meanwhile, including the far field distribution, power stability and pointing direction, two cases with large steering step and tiny steering step are evaluated. The steering time between two angles is minished to be less than the switch-off decay time. In addition, the instability on the process of beam steering is obvious although the steering step is only half of beam width. To overcome this instability, tinier steering step is suggested although it is also limited by the driving algorithm and driving circuits.

Human metapneumovirus (HmPV) is a common and serious virus that causes respiratory tract infection. This study aimed to develop a detection technique by combining reverse transcription recombinase polymerase amplification (RT-RPA) with CRISPR-Cas12a (RT-RPA-Cas12a) for clinical diagnosis of HmPV. Herein, four primer pairs targeting partial nucleoprotein (N) gene of HmPV were designed and evaluated. Then, the products amplified by RT-RPA were detected using CRISPR-Cas12a combined with fluorescence or lateral flow (LF). RT-RPA-Cas12a-based fluorescence or LF assay can be completed within 35 min or 45 min, and the detection limit was up to 6.97 × 102 copies/mL. And there was no cross reaction with human bocavirus, respiratory syncytial virus, adenovirus and parainfluenza virus. By combining with LF, the detection results were evaluated by naked eyes. Furthermore, 28 clinical samples were applied to examine the performance of RT-RPA-Cas12a system. The detection coincidence rates of RT-RPA-Cas12a-fluorescence and RT-RPA-Cas12a-LF with quantitative RT-PCR were 96.4% and 92.9%, respectively. Together, the new method for detecting HmPV with high sensitivity and specificity based on RT-RPA-Cas12a-fluorescence or LF shows promising potential for clinical diagnosis of HmPV without professional skills or ancillary equipment.

This paper proposes a novel multi-objective bee foraging algorithm (MOBFA) based on two-engine co-evolution mechanism for solving multi-objective optimization problems. The proposed MOBFA aims to handle the convergence and diversity separately via evolving two cooperative search engines with different evolution rules. Specifically, in the colony-level interaction, the primary concept is to first assign two different performance evaluation principles (i.e., Pareto-based measure and indicator-based measure) to the two engines for evolving each archive respectively, and then use the comprehensive learning mechanism over the two archives to boost the population diversity. In the individual-level foraging, the neighbor-discount-information (NDI) learning based on reinforcement learning (RL) is integrated into the single-objective searching to adjust the flight trajectories of foraging bee. By testing on a suit of benchmark functions, the proposed MOBFA is verified experimentally to be superior or at least comparable to its competitors in terms of two commonly used metrics IGD and SPREAD.

Non-mechanical laser beam steering has been reported previously in liquid crystal array devices. To be one of the most promising candidates to be practical non-mechanical laser deflector, its laser induced effect still has few theoretical model. In this paper, we propose a theoretical model to analyze this laser induced effect of LC-OPA to evaluate the deterioration on phased beam steering. The model has three parts: laser induced thermal distribution; temperature dependence of material parameters and beam steering deterioration. After these three steps, the far field of laser beam is obtained to demonstrate the steering performance with the respect to the incident laser beam power and beam waist.

Vibrio alginolyticus is an important fish pathogen causing pandemic diseases in marine animals. Small noncoding RNAs (sRNAs) are important posttranscriptional modulators of gene expression and involved in the pathogenesis of bacterial pathogens. Thus far, no cell density-dependent sRNA has been reported in V. alginolyticus. In this study, a cell density-dependent sRNA, Qrr, predicted based on the previous RNA-Seq analysis of V. alginolyticus cultured at low cell density (LCD) and high cell density (HCD), was characterized. The Qrr mutant showed significantly impaired growth and decreased swimming and swarming ability, and increased biofilm formation, extracellular polysaccharide content, serine protease production, and LD50 values during zebrafish infection in contrast to the wild-type strain. Qrr modulates the master regulators LuxR and AphA in quorum sensing (QS) pathways possibly at the posttranscriptional level by base pairing with the 5'-untranslated regions (5'-UTRs). Meanwhile, both LuxR and AphA could directly bind to the promoter of qrr to activate or repress its transcription, respectively. Moreover, our unbiased metabolic approaches revealed that Qrr modulates a large quantity of metabolic and lipidomic pathways, including amino acids, purine and pyrimidine derivatives, tricarboxylic acid cycle (TCA cycle) intermediates, and lipids. Collectively, this work contributes to a systematic understanding of regulatory roles of the cell density-dependent sRNA, Qrr, in V. alginolyticus.

Liquid crystal spatial light modulators (LC-SLMs) are usually polarization sensitive optical elements. In this paper, we propose a polarization-independent beam steering system to overcome the polarization problem of conventional liquid crystal devices by employing two polarization-dependent LC-SLMs, a polarizing beam splitter and a half-wave plate. In this system, two one-dimensional LC-SLMs are aligned orthogonally to deflect the beam in azimuthal and elevation, respectively. This system enables LC-SLMs to work in any polarization state of incident light, and can realize continuous two-dimensional laser beam pointing. Properties of polarization-independence as well as two-dimensional beam steering were mathematically and experimentally verified with a good agreement. Using the well aligned beam steering system, linearly polarized beams in different polarization angle are deflected with high accuracy and efficiency. The measured angular deviations are less than 5 micro-radians to show a high-accuracy beam steering of the system. This polarization-independent beam steering scheme is useful in the applications of nonmechanical laser communication, Lidar, and other LC-based devices.

The emergence of extensive and pandrug resistant Vibrio parahaemolyticus, which is recognized as the leading cause of seafood borne gastroenteritis globally, necessitates the urgent development of novel therapeutic strategies and antibacterial drugs. This study aims to investigate the effects of citral on the growth and virulence properties of V. parahaemolyticus RIMD2210633. Citral displayed good antibacterial activity and the minimum inhibitory concentration (MIC) was determined to be 0.125 mg/mL by two-fold broth dilution method. Citral caused damages to the bacterial cell wall and membrane, based on both the morphology observation by scanning electron microscopy and the elevated glucose content, protein leakage, and malondialdehyde content in the cell cultures. The treatment with citral at subinhibitory concentrations caused the decline in biofilm formation, motility, extracellular polysaccharide production, and also the transcription levels of genes involved in hemolysin production, type III, and VI secretion systems in V. parahaemolyticus RIMD2210633. Also, citral inhibited the quorum sensing genes and ToxRS system in a concentration dependent manner. Furthermore, the citral treated group exhibited a reduced death rate and alleviating infection symptoms of the zebrafish model caused by V. parahaemolyticus RIMD2210633. These results demonstrated that citral may be of interest as alternative therapeutics against V. parahaemolyticus associated infections in seafood.

Terrestrial plants have evolved remarkable adaptability that enables them to sense environmental stimuli and use this information as a basis for governing their growth orientation and root system development. In this paper, we explain the foraging behaviors of plant root and develop simulation models based on the principles of adaptation processes that view root growing as optimization. This provides us with new methods for global optimization. Accordingly a novel bioinspired optimizer, namely the root system growth algorithm (RSGA), is proposed, which adopts the root foraging, memory and communication and auxin-regulated mechanism of the root system. Then RSGA is benchmarked against several state-of-the-art reference algorithms on a suit of CEC2014 functions. Experimental results show that RSGA can obtain satisfactory performances on several benchmarks in terms of accuracy, robustness and convergence speed. Moreover, a comprehensive simulation is conducted to investigate the explicit adaptability of root system in RSGA. That is, in order to be able to climb noisy gradients in nutrients in soil, the foraging behaviors of root system are social and cooperative that is analogous to animal foraging behaviors.

A new method for non-mechanical laser beam splitting and steering is demonstrated. Two cascaded liquid crystal optical phased arrays (LC-OPAs) controllably modulate the amplitude and phase of an incident laser beam to realize the near-field wavefronts of multiple simultaneous beams with arbitrary directions. Diffraction between the two arrays is avoided by precise 4-f imaging from one LC-OPA to the other (array resolution 1×1920). In the method of cascaded amplitude and phase (CAP) devices, numerical simulation results show the characteristics of amplitude and phase modulation profiles, as well as the far-field intensity patterns. Both the numerical and experimental results clearly demonstrate the capabilities of fast multi-beam forming with high efficiency (>85%, 4 beams) and accuracy (deviation

To improve the working condition of liquid crystal phase shifter on incident laser power, a theoretical model on laser induced phase distortion is built on the physics of heat deposition and heat transfer. Four typical factors (absorption, heat sink structure, cooling fluid rate, and substrate) are analyzed to evaluate the influence of phase distortion when a relative high-power laser is pumped into the liquid crystal phase shifter. Flow rate of cooling fluid and heat sink structure are the most important two factors on improving the limit of incident laser power. Meanwhile, silicon wafer is suggested to replace the back glass contacting the heat sink, because of its higher heat transfer coefficient. If the device is fabricated on the conditions that: the total absorption is 5% and it has a strong heat sink structure with a flow rate of 0.01 m/s, when the incident laser power is 110W, the laser-induced phase deformation on the center is diminished to be less than 0.06, and the maximum temperature increase on the center is less than 1K degree.

Most nature-inspired algorithms simulate intelligent behaviors of animals and insects that can move spontaneously and independently. The survival wisdom of plants, as another species of biology, has been neglected to some extent even though they have evolved for a longer period of time. This paper presents a new plant-inspired algorithm which is called root growth optimizer (RGO). RGO simulates the iterative growth behaviors of plant roots to optimize continuous space search. In growing process, main roots and lateral roots, classified by fitness values, implement different strategies. Main roots carry out exploitation tasks by self-similar propagation in relatively nutrient-rich areas, while lateral roots explore other places to seek for better chance. Inhibition mechanism of plant hormones is applied to main roots in case of explosive propagation in some local optimal areas. Once resources in a location are exhausted, roots would shrink away from infertile conditions to preserve their activity. In order to validate optimization effect of the algorithm, twelve benchmark functions, including eight classic functions and four CEC2005 test functions, are tested in the experiments. We compared RGO with other existing evolutionary algorithms including artificial bee colony, particle swarm optimizer, and differential evolution algorithm. The experimental results show that RGO outperforms other algorithms on most benchmark functions.

To prevent worms from propagating rapidly, it is essential to generate worm signatures quickly and accurately. However, existing methods for generating worm signatures either cannot handle noise well or assume there is only one kind of worm sequence in the suspicious flow pool. We propose an approach based on seed extending signature generation SESG to generate polymorphic worm signatures from a suspicious flow pool which includes several kinds of worm and noise sequences. The proposed SESG algorithm computes the weight of every sequence, the sequences are queued based on their weight, and then classified. Worm signatures are then generated from the classified worm sequences. We compare SESG with other approaches. SESG can classify worm and noise sequences from a suspicious flow pool, and generate effective worm signatures more easily.