Treadmill exercise in combination with acousto-optic and olfactory stimulation improves cognitive function in APP/PS1 mice through the brain-derived neurotrophic factor-and Cygb-associated signaling pathways

A reduction in adult neurogenesis is associated with behavioral abnormalities in patients with Alzheimer's disease.Consequently,enhancing adult neurogenesis represents a promising therapeutic approach for mitigating disease symptoms and progression.Nonetheless,nonpharmacological interventions aimed at inducing adult neurogenesis are currently limited.Although individual non-pharmacological interventions,such as aerobic exercise,acousto-optic stimulation,and olfactory stimulation,have shown limited capacity to improve neurogenesis and cognitive function in patients with Alzheimer's disease,the therapeutic effect of a strategy that combines these interventions has not been fully explored.In this study,we observed an age-dependent decrease in adult neurogenesis and a concurrent increase in amyloid-beta accumulation in the hippocampus of amyloid precursor protein/presenilin 1 mice aged 2-8 months.Amyloid deposition became evident at 4 months,while neurogenesis declined by 6 months,further deteriorating as the disease progressed.However,following a 4-week multifactor stimulation protocol,which encompassed treadmill running(46 min/d,10 m/min,6 days per week),40 Hz acousto-optic stimulation(1 hour/day,6 days/week),and olfactory stimulation(1 hour/day,6 days/week),we found a significant increase in the number of newborn cells(5'-bromo-2'-deoxyuridine-positive cells),immature neurons(doublecortin-positive cells),newborn immature neurons(5'-bromo-2'-deoxyuridine-positive/doublecortin-positive cells),and newborn astrocytes(5'-bromo-2'-deoxyuridine-positive/glial fibrillary acidic protein-positive cells).Additionally,the amyloid-beta load in the hippocampus decreased.These findings suggest that multifactor stimulation can enhance adult hippocampal neurogenesis and mitigate amyloid-beta neuropathology in amyloid precursor protein/presenilin 1 mice.Furthermore,cognitive abilities were improved,and depressive symptoms were alleviated in amyloid precursor protein/presenilin 1 mice following multifactor stimulation,as evidenced by Morris water maze,novel object recognition,forced swimming test,and tail suspension test results.Notably,the efficacy of multifactor stimulation in consolidating immature neurons persisted for at least 2weeks after treatment cessation.At the molecular level,multifactor stimulation upregulated the expression of neuron-related proteins(NeuN,doublecortin,postsynaptic density protein-95,and synaptophysin),anti-apoptosis-related proteins(Bcl-2 and PARP),and an autophagyassociated protein(LC3B),while decreasing the expression of apoptosis-related proteins(BAX and caspase-9),in the hippocampus of amyloid precursor protein/presenilin 1 mice.These observations might be attributable to both the brain-derived neurotrophic factor-mediated signaling pathway and antioxidant pathways.Furthermore,serum metabolomics analysis indicated that multifactor stimulation regulated differentially expressed metabolites associated with cell apoptosis,oxidative damage,and cognition.Collectively,these findings suggest that multifactor stimulation is a novel non-invasive approach for the prevention and treatment of Alzheimer's disease.

Controlling and synchronizing spatiotemporal chaos of the coupled Bragg acousto-optical bistable map system using nonlinear feedback

In this paper we present the control and synchronization of a coupled Bragg acousto-optic bistable map system using nonlinear feedback technology. This nonlinear feedback technology is useful to control a temporally chaotic system as well as a spatiotemporally chaotic system. It can be extended to synchronize the spatiotemporal chaos. It can work in a wide range of the controlled and synchronized signals, so it can decrease the sensitivity down to a noise level. The synchronization can be obtained by the analysis of the largest conditional Lyapunov exponent spectrum, and easily implemented in practical systems just by adjusting the coupled strength without any pre-knowledge of the dynamic system required.

Acousto-Optically Q-Switched Operation of Yb:CNGG Disordered Crystal Laser

We report the repetitively Q-switched laser operation of the Yb-doped calcium niobium gallium garnet disordered garnet crystal, achieved with an acousto-optic modulator in a compact plano-concave resonator that is endpumped by a 935-nm diode laser. An average output power of 1.96 W is produced at pulse repetition rate of50 k Hz at emission wavelengths around 1035 nm, with a slope efficiency of 16%. The highest pulse energy of 269 μJ is generated at pulse repetition rate of 1 k Hz, with pulse width 12.1 ns and peak power 20.53 kW.

High-Resolution Broadband Millimeter-Wave Astrophysical Spectrometer with Triple Product Acousto-Optical Processor

An advanced conceptual design of a high-bit-rate triple product acousto-optical processor is presented that can be applied in a number of astrophysical problems. We briefly describe the Large Millimeter Telescope as one of the potential observational infrastructures where the acousto-optical spectrometer can be successfully used. A summary on the study of molecular gas in relatively old (age > 10 Myr) disks around main sequence stars is provided. We have identified this as one of the science cases in which the proposed processor can have a big impact. Then we put forward triple product acousto-optical processor is able to realize algorithm of the space-and-time integrating, which is desirable for a wideband spectrum analysis of radio-wave signals with an improved resolution providing the resolution power of about 105 - 106. It includes 1D-acousto-optic cells as the input devices for a 2D-optical data processing. The importance of this algorithm is based on exploiting the chirp Z-transform technique providing a 2D-Fourier transform of the input signals. The system produces the folded spectrum, accumulating advantages of both space and time integrating. Its frequency bandwidth is practically equal to the bandwidth of transducers inherent in acousto-optical cells. Then, similar processor is able to provide really high frequency resolution, which is practically equal to the reciprocal of the CCD-matrix photo-detector integration time. Here, the current state of developing the triple product acousto-optical processor in frames of the astrophysical instrumentation is shortly discussed.

High-Power Continuous-Wave and Acousto-Optical Q-Switched Ho:(Sc_(0.5)Y_(0.5))_2SiO_5 Laser Pumped by Laser Diode

We experimentally investigate the continuous-wave(cw)and acousto-optical(AO)Q-switched performance of a diode-pumped Ho:(Sc_(0.5)Y_(0.5))_2SiO_5(Ho:SYSO)laser.A fiber-coupled laser diode at 1.91m is employed as the pump source.The cw Ho:SYSO laser produces 13.0 W output power at 2097.9 nm and 56.0%slope efficiency with respect to the absorbed pump power.In the AO Q-switched regime,at a pulse repetition frequency of 5 kHz,the Ho:SYSO laser yields 2.1 mJ pulse energy and 21 ns pulse width,resulting in a calculated peak power of 100 k W.In addition,at the maximum output level,the beam quality factor of the Q-switched Ho:SYSO laser is measured to be about 1.6.

High-power xenon lamp-pumped Er:YAP pulse laser operated in free-running and acousto-optical Q-switching modes

We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that the thermal lens effect is gradually aggravated with the increase of working frequencies, and even working at 100 Hz, a single pulse energy of 234 m J can be achieved. A maximum average power of 41.5 W is achieved with a working frequency of 20 Hz and slope efficiency of 2.82%. This output power is much higher than other xenon lamp-pumped erbium laser devices.A Q-switched laser is demonstrated by using the TeO2crystal, the maximum output energies of 11.5 m J and 3.5 m J are obtained at 50 and 100 Hz, the corresponding peak powers are 93.4 k W and 17.2 kW, respectively.The laser wavelengths and beam quality factors are also characterized in the free-running and Q-switched modes. A higher pulse energy and peak power laser could be achieved further by improving the damage threshold of TeO2acousto-optical Q-switching. All the experimental results illustrate that the xenon lamp-pumped Er:YAP laser is a promising candidate for high-power and high-frequency mid-infrared laser devices.

Optical Spectrometer with Acousto-Optical Dynamic Grating for Guillermo Haro Astrophysical Observatory

Optical spectrometer of the Guillermo Haro astrophysical observatory (Mexico) realizes investigations in the visible and near-infrared range 350 - 800 nm and exploits mechanically removable traditional static diffraction gratings as dispersive elements. There is a set of the static gratings with slit-densities 150 - 600 lines/mm and optical apertures 9 cm × 9 cm that provide the first order spectral resolution from 0.8 to 3.2 A/pixel, respectively. However, the needed mechanical manipulations, namely, replacing the static diffraction gratings with various resolutions and following recalibration of spectrometer within studying even the same object are practically inconvenient and lead to wasting rather expensive observation time. We suggest exploiting an acousto-optical cell, i.e. the dynamic diffraction grating tunable electronically, as dispersive element in that spectrometer. Involving the acousto-optical technique, which can potentially provide electronic control over the spectral resolution and the range of observations, leads to eliminating the abovementioned demerits and improving the efficiency of analysis.

Developing an Advanced Prototype of the Acousto-Optical Radio-Wave Spectrometer for Studying Star Formation in the Milky Way

The designed practically prototype of an advanced acousto-optical radio-wave spectrometer is presented in a view of its application to investigating the Milky Way star formation problems. The potential areas for observations of the cold interstellar medium, wherein such a spectrometer can be exploited successfully at different approximations, are: 1) comparison of the Milky Way case with extragalactic ones at scale of the complete galactic disk;2) global studies of the Galactic spiral arms;and 3) characterization of specific regions like molecular clouds or star clusters. These aspects allow us to suggest that similar instrument will be really useful. The developed prototype of spectrometer is able to realize multi-channel wideband parallel spectrum analysis of very-high-frequency radio-wave signals with an improved resolution power exceeding 103. It includes the 1D-acousto-optic wide-aperture cell as the input device for real-time scale data processing. Here, the current state of developing this acousto-optical spectrometer in frames of the astrophysical instrumentation is briefly discussed, and the data obtained experimentally with a tellurium dioxide crystalline acousto-optical cell are presented. Then, we describe a new technique for more precise spectrum analysis within an algorithm of the collinear wave heterodyning. It implies a two-stage integrated processing, namely, the wave heterodyning of a signal in an acoustically square-law nonlinear medium and then the optical processing in the same solid-state cell. Technical advantage of this approach lies in providing a direct multi-channel parallel processing of ultra-high-frequency radio-wave signals with the resolution power exceeding 104. This algorithm can be realized on a basis of exploiting a large-aperture effective acousto-optical cell, which operates in the Bragg regime and performs the ultra-high-frequency co-directional collinear acoustic wave heterodyning. The general concept and basic conclusions here are confirmed by proof-of-principle experiments with the specially designed cell of a new type based on a lead molybdate crystal.

Interaction Mechanisms between Natural Debris Flow and Rigid Barrier Deflectors:A New Perspective for Rational Design and Optimal Arrangement

Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention requirements.However,the mechanisms of interaction between natural granular flow and rigid barrier deflectors require further investigation.To date,few studies have investigated the impact of deflectors on controlling viscous debris flows for geological disaster prevention.To investigate the effect of rigid barrier deflectors on impact mechanisms,a numerical model using the smoothed particle hydrodynamics(SPH)method with the Herschel–Bulkley model is proposed to simulate the interaction between natural viscous flow and single/dual barriers with and without deflectors.This model was validated using laboratory flume test data from the literature.Then,the model was used to investigate the influence of the deflector angle and multi-barrier arrangements.The optimal configuration of multi-barriers was analyzed with consideration to the barrier height and distance between the barriers,because these metrics have a significant impact on the viscous flow pile-up,run-up,and overflow mechanisms.The investigation considered the energy dissipation process,retention efficiency,and dead-zone formation.Compared with bare barriers with similar geometric characteristics and spatial distribution,rigid barriers with deflectors exhibit superior effectiveness in preventing the overflow and overspilling of viscous debris flow.Recommendations for the rational design of deflectors and the optimal arrangement of multi-barriers are provided to mitigate geological disasters.

Numerical investigation on the aerodynamic drag reduction based on bottom deflectors and streamlined bogies of a high-speed train

The complex structure of the bottom of a high-speed train is an important source of train aerodynamic drag.Thus,improving the bottom structure is of great significance to reduce the aerodynamic drag of the train.In this study,computational fluid dynamics(CFD)based on three-dimensional steady incompressible Reynolds-average Naiver-Stokes(RANS)equations and Realizable k-ε turbulence model were utilized for numerical simulations.Inspired by the concept of streamlined design and the idea of bottom flow field control,this study iteratively designed the bogies in a streamlined shape and combined them with the bottom deflectors to investigate the joint drag reduction mechanism.Three models,i.e.,single-bogie model,simplified train model,and eight-car high-speed train model,were created and their aerodynamic characteristics were analyzed.The results show that the single-bogie model with streamlined design shows a noticeable drag reduction,whose power bogie and trailer bogie experience 13.92%and 7.63%drag reduction,respectively.The range of positive pressure area on the bogie is reduced.The aerodynamic drag can be further reduced to 15.01%by installing both the streamlined bogie and the deflector on the simplified train model.When the streamlined bogies and deflectors are used on the eight-car model together,the total drag reduction rate reaches 2.90%.Therefore,the proposed aerodynamic kit for the high-speed train bottom is capable to improve the flow structure around the bogie regions,reduce the bottom flow velocity,and narrow the scope of the train’s influence on the surrounding environment,achieving the appreciable reduction of aerodynamic drag.This paper can provide a new idea for the drag reduction of high-speed trains.

An Advanced Multi-Band Acousto-Optical Radio-Wave Spectrometer with Multi-Channel Frequency Processing for Astrophysical Studies

We present an advanced schematic arrangement of the radio-wave spectrometer with a few parallel optical arms for processing the data flow. This arrangement includes two principal novelties. First of them consists in the proposed design, where each individual optical arm exhibits its original performances providing parallel multi-band observations within a few different scales simultaneously. These optical arms have the beam shapers providing both the needed incident light polarization and apodization to increase the dynamic range. After parallel acousto-optical processing, data flows of all the optical arms are united by the joint CCD matrix on the stage of the combined electronic data processing. The second novelty is in usage of unique wide-aperture bastron-based acousto-optical cell providing one of the best performances at the middle-frequencies (about 500 MHz) in comparison with the other available crystalline materials in this range. Such multi-band capabilities have a number of applications in astrophysical scenarios at different scales: from objects in the distant universe to planetary atmospheres in the Solar system. Thus one yields the united versatile instrument, which provides comprehensive studies of astrophysical objects simultaneously with precise synchronization in various frequency ranges.

Experimental and Numerical Investigation on the Aerodynamic Characteristics of High-Speed Pantographs with Supporting Beam Wind Deflectors

Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to support the beam deflector optimization using a combination of experimental measurements and computational fluid dynamics(CFD)simulations.The results demonstrate that the size,position,and installation orientation of the wind deflectors significantly influence the amount of force compensation.They also indicate that the front strip deflectors should be installed downwards and the rear strip deflectors upwards,thereby forming a“π”shape.Moreover,the lift force compensation provided by the wind deflectors increases with the size of the deflector.Alternative wind compensation strategies,such as control circuits,are also discussed,putting emphasis on the pros and cons of various pantograph types and wind compensation approaches.

沥青路面热风循环加热机导流板结构参数优化

为提高沥青路面热风循环加热效率,以热风循环加热机导流板为研究对象,采用有限差分法和泰勒级数展开法对射流冲击传热问题进行数值求解,建立沥青路面流固耦合传热模型;采用有限元软件FLUENT仿真分析热风射流冲击传热流场,研究导流板内侧倾斜角度(45°、50°、55°、60°、65°、70°)、外侧倾斜角度(30°、35°、40°、45°、50°)对加热效率的影响规律,采用正交试验设计法制定30组试验方案,获得不同内、外侧倾斜角度下沥青路面的温度场分布;计算特定温度目标下热风循环加热时长,确定热风循环加热机导流板的结构参数。结果表明:当内、外侧导流板倾斜角度不变时,加热效率随外、内侧导流板倾斜角度的增大先减小后增大。当内、外侧导流板倾斜角度分别为60°、40°时,热风循环加热沥青路面的加热效率较高。

Research on the jet characteristics of the deflector–jet mechanism of the servo valve

In view of the complicated structure of the deflector-jet mechanism,a mathematical model based on the turbulent jet flow theory in the deflector-jet amplifier is proposed.Considering the energy transformation and momentum variation,an equation of the flow velocity distribution at the key fluid region is established to describe the morphological changes of the fluid when it passes through the deflector and jets into the receiver.Moreover,the process is segmented into four stages.According to the research results,the oil enters the deflector and impinges with the side wall.Then one part of the oil＇s flow velocity decreases and a high pressure zone is formed by the oil accumulation,the other part of the oil reverses out of the deflector along the side wall.Prior to entering the receiver,the flow is a kind of plane impinging jet.Virtually,the working pressure of the receiver is generated by the impact force,while the high speed fluid flows out of the receiver and forms a violent vortex,which generates negative pressure and causes the oil to be gasified.Compared with the numerical simulation results,the turbulent jet model that can effectively describe the characteristics of the deflector-jet mechanism is accurate.In addition,the calculation results of the prestage pressure characteristic have been verified by experiments.

Numerical Analysis and Verification of the Gas Jet from Aircraft Engines Impacting a Jet Blast Deflector

The process of the gas jet from aircraft engines impacting a jet blast deflector is not only a complex fluid–solid coupling problem that is not easy to compute, but also a safety issue that seriously interferes with flight deck envi?ronment. The computational fluid dynamics(CFD) method is used to simulate numerically the impact e ect of gas jet from aircraft engines on a jet blast deflector by using the Reynolds?averaged Navier?Stokes(RANS) equations and turbulence models. First of all, during the pre?processing of numerical computation, a sub?domains hybrid meshing scheme is adopted to reduce mesh number and improve mesh quality. Then, four di erent turbulence models includ?ing shear?stress transport(SST) k-w, standard k-w, standard k-ε and Reynolds stress model(RSM) are used to compare and verify the correctness of numerical methods for gas jet from a single aircraft engine. The predicted values are in good agreement with the experimental data, and the distribution and regularity of shock wave, velocity, pressure and temperature of a single aircraft engine are got. The results show that SST k?w turbulence model is more suitable for the numerical simulation of compressible viscous gas jet with high prediction accuracy. Finally, the impact e ect of gas jet from two aircraft engines on a jet blast deflector is analyzed based on the above numerical method, not only the flow parameters of gas jet and the interaction regularity between gas jet and the jet blast deflector are got, but also the thermal shock properties and dynamic impact characteristics of gas jet impacting the jet blast deflector are got. So the dangerous activity area of crew and equipments on the flight deck can be predicted qualitatively and quantitatively. The proposed research explores out a correct numerical method for the fluid–solid interaction during the impact process of supersonic gas jet, which provides an e ective technical support for design, thermal ablation and structural damage analysis of a new jet blast deflector.

Acousto-optic scanning spatial-switching multiphoton lithography

Nano-3D printing has obtained widespread attention owing to its capacity to manufacture end-use components with nano-scale features in recent years.Multiphoton lithography(MPL)is one of the most promising 3D nanomanufacturing technologies,which has been widely used in manufacturing micro-optics,photonic crystals,microfluidics,meta-surface,and mechanical metamaterials.Despite of tremendous potential of MPL in laboratorial and industrial applications,simultaneous achievement of high throughput,high accuracy,high design freedom,and a broad range of material structuring capabilities remains a long-pending challenge.To address the issue,we propose an acousto-optic scanning with spatial-switching multispots(AOSS)method.Inertia-free acousto-optic scanning and nonlinear swept techniques have been developed for achieving ultrahigh-speed and aberration-free scanning.Moreover,a spatial optical switch concept has been implemented to significantly boost the lithography throughput while maintaining high resolution and high design freedom.An eight-foci AOSS system has demonstrated a record-high 3D printing rate of 7.6×10^(7)voxel s^(-1),which is nearly one order of magnitude higher than earlier scanning MPL,exhibiting its promise for future scalable 3D nanomanufacturing.

All-dielectric metasurface beam deflector at the visible frequencies

Beam deflectors are important optical elements which can control the propagation direction of the beam in free space.However,with the development of miniaturization of the optical systems,conventional reflector-based mechanical beam deflectors confront a huge challenge due to their large sizes and incompatibility to the device integration.Here we propose an all-dielectric flat metasurface beam deflector which is composed of a single layer array of TiO_2 nanoantennas resting on a fused-silica substrate.Numerical simulations are performed to demonstrate that the proposed deflectors are able to efficiently deflect the incident beam for different angles with transmission efficiency higher than 80%at visible frequencies.This ultrathin all-dielectric metasurface deflector may have great potential applications in integrated optics.

A Comparative Study on Hydrodynamic Performance of Double Deflector Rectangular Cambered Otter Board

In the present work,the hydrodynamic performance of the double deflector rectangular cambered otter board was studied using wind tunnel experiment,flume tank experiment and numerical simulation.Results showed that the otter board had a good hydrodynamic performance with the maximum lift-to-drag ratio(K_(MAX) = 3.70).The flow separation occurred when the angle of attack(AOA) was at 45?,which revealed that the double deflector structure of the otter board can delay the flow separation.Numerical simulation results showed a good agreement with experiment ones,and could predict the critical AOA,which showed that it can be used to study the hydrodynamic performance of the otter board with the advantage of flow visualization.However,the drag coefficient in flume tank was much higher than that in wind tunnel,which resulted in a lower lift-to-drag ratio.These may be due to different fluid media between flume tank and wind tunnel,which result in the big difference of the vortexes around the otter board.Given the otter boards are operated in water,it was suggested to apply both flume tank experiment and numerical simulation to study the hydrodynamic performance of otter board.

Numerical studies on four-engine rocket exhaust plume impinging on flame deflectors with afterburning

This paper studies the four-engine liquid rocket flow field during the launching phase.Using threedimensional compressible Navier-Stokes equations and two-equation realizable k-epsilon turbulence model,an impact model is established and flow fields of plume impinging on the two different shapes of flame deflectors,including wedge-shaped flame deflector and cone-shaped flame deflector,are calculated.The finite-rate chemical kinetics is used to track chemical reactions.The simulation results show that afterburning mainly occurs in the mixed layer.And the region of peak pressure occurs directly under the rocket nozzle,which is the result of the direct impact of exhaust plume.Compared with the wedgeshaped flame deflector,the cone-shaped flame deflector has great performance on guiding exhaust gas.The wedge-shaped and cone-shaped flame deflectors guide the supersonic exhaust plume away from the impingement point with two directions and circumferential direction,respectively.The maximum pressure and temperature on the wedge-shaped flame deflector surface are 37.2%and 9.9%higher than those for the cone-shaped flame deflector.The results provide engineering guidance and theoretical significance for design in flame deflector of the launch platforms.

A Modified Monte Carlo Model of Speckle Tracking of Shear Wave Induced by Acoustic Radiation Force for Acousto-Optic Elasticity Imaging

A modified Monte Carlo model of speckle tracking of shear wave propagation in scattering media is proposed. The established Monte Carlo model mainly concerns the variations of optical electric field and speckle. The two- dimensional intensity distribution and the time evolution of speckles in different probe locations are obtained. The fluctuation of speckle intensity tracks the acoustic-radiation-force shear wave propagation, and especially the reduction of speckle intensity implies attenuation of shear wave. Then, the shear wave velocity is estimated quantitatively on the basis of the time-to-peak algorithm and linear regression processing. The results reveal that a smaller sampling interval yields higher estimation precision and the shear wave velocity is estimated more efficiently by using speckle intensity difference than by using speckle contrast difference according to the estimation error. Hence, the shear wave velocity is estimated to be 2.25 m/s with relatively high accuracy for the estimation error reaches the minimum （0.071）.