Luminescence of Sm3+ in double perovskite-type Ba2SrWO6 for insect trapping.

The predominant method for pest control has been the use of pesticides, which have been shown to have detrimental effects on soil, freshwater, and crop quality. Therefore, the development of novel and sustainable crop protection strategies has become increasingly imperative. In this study, a novel orange-red emitting Ba2SrWO6: Sm3+ phosphor was synthesized using the high-temperature solid-state reaction. Under ultraviolet excitation, the phosphors showed obvious emission peaks at 575, 614, and 662 nm. The Ba2SrWO6: Sm3+ was used to fabricate a fluorescence film with polydimethylsiloxane (PDMS), and attracted twice as many insects as the blank control group under 365 nm ultraviolet light. This material holds great potential as a fluorescent agent for insect trapping in the pest control fields of tea, cotton, eggplant, rice, potato, grape, and other agricultural industries. Our findings provide an eco-friendly approach to pest management for the increment of food production.

Quantitative determination of microbial materials activity based on infrared extinction properties.

Microbial bacteria play an irreplaceable role in natural and human production and life; thus, determining their activities is an important issue. This study proposed a method to quantitatively determine the activity of microbial materials through extinction property calculation using infrared spectroscopy. Complex refractive indices of different active biomaterials were calculated based on their infrared spectra, and their extinction properties were determined using the discrete dipole approximation method. Using partial least squares (PLS), support vector regression (SVR), and extreme learning machine (ELM) regression, quantitative determination models of microbial materials based on infrared extinction properties were established to predict their activity. The results demonstrated that the model of least angle regression (LAR) combined with PLS exhibited better potential for the determination of biomaterial activity. The coefficient of determination (R2) values acquired by the optimal model for the three biomaterials were 0.9699, 0.9744, and 0.9621, respectively. These findings suggested that a rapid and accurate quantitative determination of microbial activity can be achieved based on extinction property.

A Natural Glucan from Black Bean Inhibits Cancer Cell Proliferation via PI3K-Akt and MAPK Pathway.

A natural α-1,6-glucan named BBWPW was identified from black beans. Cell viability assay showed that BBWPW inhibited the proliferation of different cancer cells, especially HeLa cells. Flow cytometry analysis indicated that BBWPW suppressed the HeLa cell cycle in the G2/M phase. Consistently, RT-PCR experiments displayed that BBWPW significantly impacts the expression of four marker genes related to the G2/M phase, including p21, CDK1, Cyclin B1, and Survivin. To explore the molecular mechanism of BBWPW to induce cell cycle arrest, a transcriptome-based target inference approach was utilized to predict the potential upstream pathways of BBWPW and it was found that the PI3K-Akt and MAPK signal pathways had the potential to mediate the effects of BBWPW on the cell cycle. Further experimental tests confirmed that BBWPW increased the expression of BAD and AKT and decreased the expression of mTOR and MKK3. These results suggested that BBWPW could regulate the PI3K-Akt and MAPK pathways to induce cell cycle arrest and ultimately inhibit the proliferation of HeLa cells, providing the potential of the black bean glucan to be a natural anticancer drug.

Actuation technologies for magnetically guided catheters.

Due to their wide range of clinical application possibilities, magnetic actuation technologies have grabbed the attention of researchers worldwide. The design, execution, and analysis of magnetic catheter systems have advanced significantly during the last decade. The review focuses on magnetic actuation for catheter steering and control of the device, which will be explored in detail in the following sections. There is a discussion of future work and the challenges of the review systems, and the conclusions are finally addressed.

Reduction of speckle noise in digital holography using a neighborhood filter based on multiple sub-reconstructed images.

The application of digital holography in several fields is limited since speckle destroys the original information of the reconstructed image. This paper proposes a neighborhood filter based on multiple sub-reconstructed images according to the random distribution of speckle noise. In this method, the denoised value is equal to the weighted sum of neighboring pixel values, and the weight is calculated by the degree of correlation between different positions of multiple sub-holograms. The experimental results show that the method can greatly reduce the speckle noise, and its noise reduction performance is superior to traditional digital image processing algorithms.

Speckle reduction in digital holography with non-local means filter based on the Pearson correlation coefficient and Butterworth filter.

This Letter presents a non-local means filter based on the Pearson correlation coefficient and Butterworth high-pass filter. In the method, the new gray value of the denoising pixel is equal to the weighted sum of the surrounding pixel values. We use the Pearson correlation coefficient between the pixels to calculate the weight of the surrounding pixels to the denoising pixel, then use Butterworth high-pass filter to optimize. Experimental results show that the method effectively reduces the speckle noise of digital holography and the image details are also very rich. At the same time, its performance is still better when compared with methods such as BM3D.

Nonlocal means filter based on cosine similarity applied in speckle reduction of digital holography.

In the field of digital holography, the speckle caused by coherent light greatly disturbs the quality of the reconstruction. This paper presents an innovative method to efficiently reduce speckle noise with a nonlocal means filter based on cosine similarity that determines the weight of each traversal pixel to the target pixel by comparing the similarity between the target pixel neighborhood and the traversal pixel neighborhood. Experimental results with qualitative and quantitative analysis indicate that the proposed method significantly improves noise reduction performance while preserving the details of the original image. Compared with other general image-processing methods, this well-directed method is more in line with the characteristics of holographic speckle noise and has obvious advantages in various metrics.

Elimination of abnormal phase fluctuation in digital holography.

In digital holography, the phase is most important, and the quality of the reconstructed phase determines the final reconstructed image effect. However, noise is inevitably introduced in the process of recording the hologram. For regions without object light, the phase has a random distribution, which affects the final phase quality. This kind of noise is called abnormal phase fluctuations in this paper. The correlation between amplitude and phase in digital holography is used to judge whether there is useful phase information. Through structural similarity and the light-dark relationship, a credible probability mask is introduced to extract the phase that needs to be preserved. The simulation and experimental results show that abnormal phase fluctuations are successfully removed, and the useful phase information is retained.

Calculation of Stokes vector of laser backscattering from typical geometric rough surfaces at a long distance.

The polarization bidirectional reflectance distribution function is key to establishing the relationships between incident and backscattering Stokes vectors. For analytical calculation of Stokes vectors of backscattering light from rough surfaces of objectives at long distances, we treat complicated objectives as a combination of several typical geometric surfaces. The analytical calculation forms of Mueller matrices of typical geometric rough surfaces at different sizes and geometric parameters are presented using a microfacet model, and thus, the backscattering Stokes vectors are determined. Experimental results of four types of geometric forms show good agreement with theoretical simulation, except when the incident angle is larger than about 60° at a wavelength of 532 nm. Further studies should be focused on improving the microfacet model for fitting the experimental results at large incident angles, and effects of multiple reflections between different geometric surfaces cannot be neglected when the combination of typical geometric surfaces is considered.

Security Performance Analysis of LEO Satellite Constellation Networks under DDoS Attack.

Low Earth orbit satellite constellation networks (LSCNs) have attracted significant attention around the world due to their great advantages of low latency and wide coverage, but they also bring new challenges to network security. Distributed denial of service (DDoS) attacks are considered one of the most threatening attack methods in the field of Internet security. In this paper, a space-time graph model is built to identify the key nodes in LSCNs, and a DDoS attack is adopted as the main means to attack the key nodes. The scenarios of two-satellite-key-node and multi-satellite-key-node attacks are considered, and their security performance against DDoS attacks is also analyzed. The simulation results show that the transmission path of key satellite nodes will change rapidly after being attacked, and the average end-to-end delay and packet loss are linearly related to the number of key-node attacks. This work provides a comprehensive analysis of the security performance of LSCNs under a DDoS attack and theoretical support for future research on anti-DDoS attack strategies for LSCNs.

Speckle reduction in digital holography with low-dimensional reconstruction.

Speckle reduction is a crucial technique since the presence of speckle disturbs the quality of the reconstruction in digital holography. In this paper, we present an easy, fast, and efficient single-shot method to reduce speckle noise in digital holography. The method reconstructs subholograms from a single hologram. Then, sub-reconstruction images are randomly shuffled and divided into several groups and low-dimensional noise-reduced images can be achieved by averaging sub-reconstruction image groups by groups. Next, these low-dimensional noise-reduced images are combined to obtain a noise-reduced image. Finally, the noise-reduced image is processed by a mean filter to obtain a final image, which has substantially less speckle noise while preserving the dimensions of the original image. The experimental results demonstrate the effectiveness of the proposed method and indicate its potential in real-time digital holography.

Immunoregulation and antioxidant activities of a novel acidic polysaccharide from Radix Paeoniae Alba.

Radix Paeoniae Alba is widely used in Chinese traditional medicine to treat various diseases such as gastrointestinal disorders, immunomodulatory, cancer, and other diseases. In this paper, a novel acidic polysaccharide RPAPS purified from Radix Paeoniae Alba was evaluated for its structural features and potential of immunomodulatory and antioxidant activities. RPAPS (molecular weight: 1.0× 105 Da) was mainly composed of α-(1 → 4)-Glcp, α-Arap, α-Galp, α-Rhap, ß-D-Glcp, α-(1 → 6)-linked Glcp and GalA. Immunological tests indicated that RPAPS could improve RAW264.7 phagocytic activity and LPS-induced splenocyte proliferation. For antioxidant activities, RPAPS showed reducing power and DPPH scavenging activity in dose dependent. Moreover, RPAPS could significantly protect the PC12 cells from H2O2 damage. These data implied polysaccharides RPAPS had the potential to be novel natural antioxidative and immunopotentiating agents for using in functional foods or medicine.

Independently tunable Fano resonances in a metal-insulator-metal coupled cavities system.

Herein, multiple Fano resonances with excellent ability to be tuned independently are produced in a sub-wavelength metal-insulator-metal system. The input and output waveguides are separated by a metal gap, and a stub and an end-coupled cavity are placed below and to the right side of the input waveguide, respectively, as discrete states. Owing to the mode interferences, double ultra-sharp and asymmetric Fano resonant peaks are observed in the transmission spectrum. Successfully, the basic structure is extended by two extra rectangular cavities, giving rise to four Fano resonances with high refractive index sensitivity and figure of merit. Due to the discrete modes of Fano resonances from different coupling cavities, their resonant wavelengths can be controlled independently, which can provide greater flexibility for tuning Fano resonances. The performances of the proposed structure are investigated by both the finite-difference time-domain method and the multimode interference coupled-mode theory. It is believed that the research can provide important guidance in designing Fano resonance structures, and the proposed structure has a wide application in sensors, switches, and nano-photonic integrated circuit devices.

Single-shot speckle reduction by elimination of redundant speckle patterns in digital holography.

Speckle reduction is a crucial technique, since the presence of speckle disturbs the quality of the reconstruction in digital holography. In this paper, we present a redundant speckle elimination method to suppress the speckle noise. For the same position in each of the reconstructed sub-images, we consider pixels with the same gray value as information with the same speckle distribution. Therefore, a speckle-suppressed gray value can be obtained by extracting pixels with different gray values and then averaging. Through theoretical analysis and experiments, we demonstrate that speckle contrast can be decreased significantly by using the proposed method. Moreover, we show that the despeckle strength of the proposed method highly depends on the number of binary masks. These results indicate the potential of the proposed method for various applications.

Dynamic behaviors of hyperbolic-type memristor-based Hopfield neural network considering synaptic crosstalk.

Crosstalk phenomena taking place between synapses can influence signal transmission and, in some cases, brain functions. It is thus important to discover the dynamic behaviors of the neural network infected by synaptic crosstalk. To achieve this, in this paper, a new circuit is structured to emulate the Coupled Hyperbolic Memristors, which is then utilized to simulate the synaptic crosstalk of a Hopfield Neural Network (HNN). Thereafter, the HNN's multi-stability, asymmetry attractors, and anti-monotonicity are observed with various crosstalk strengths. The dynamic behaviors of the HNN are presented using bifurcation diagrams, dynamic maps, and Lyapunov exponent spectrums, considering different levels of crosstalk strengths. Simulation results also reveal that different crosstalk strengths can lead to wide-ranging nonlinear behaviors in the HNN systems.

Effects of relative humidity on the broadband extinction performance of bioaerosol.

Bioaerosol, a significant constituent of the atmosphere, exhibits excellent broadband extinction performance and has attracted increasing attentions in the fields of atmospheric science, environmental science and electromagnetic field, et al. Relative humidity of the atmosphere has obvious diurnal and seasonal variation characteristics, and the frequent variation of relative humidity has a significant impact on bioaerosol in the atmosphere. However, the influence of relative humidity on broadband extinction performance of bioaerosol is unclear. Herein, we present the humidity growth model of bioaerosol. And the variation law of broadband extinction performance of bioaerosol in different humidity conditions was obtained by simulation. The simulation results and experimental data from an aerosol chamber experiment show that as the relative humidity values above 70%, the broadband extinction performance of bioaerosol will be increased with humidity. As the relative humidity increases from 70% to 90%, the extinction performance of AN0913 spores increase about 30% in visible and mid-infrared bands, about 20% in ultraviolet and far-infrared bands. And the extinction performance of AO0907 spores increase about 23% in the all four bands.

One-Stage Multi-Sensor Data Fusion Convolutional Neural Network for 3D Object Detection.

Three-dimensional (3D) object detection has important applications in robotics, automatic loading, automatic driving and other scenarios. With the improvement of devices, people can collect multi-sensor/multimodal data from a variety of sensors such as Lidar and cameras. In order to make full use of various information advantages and improve the performance of object detection, we proposed a Complex-Retina network, a convolution neural network for 3D object detection based on multi-sensor data fusion. Firstly, a unified architecture with two feature extraction networks was designed, and the feature extraction of point clouds and images from different sensors realized synchronously. Then, we set a series of 3D anchors and projected them to the feature maps, which were cropped into 2D anchors with the same size and fused together. Finally, the object classification and 3D bounding box regression were carried out on the multipath of fully connected layers. The proposed network is a one-stage convolution neural network, which achieves the balance between the accuracy and speed of object detection. The experiments on KITTI datasets show that the proposed network is superior to the contrast algorithms in average precision (AP) and time consumption, which shows the effectiveness of the proposed network.

Discrimination of viable and dead microbial materials with Fourier transform infrared spectroscopy in 3-5 micrometers.

We present a method to show that average mass extinction coefficient of microbes evaluated via Lorenz-Mie theory can be used to discriminate between viable and dead microbes. Reflectance of viable and dead self-cultured fungal spores and mycelia were measured by the Fourier transform infrared spectroscopy. Complex refractive indices and mass extinction coefficient of viable and dead fungal spores and mycelia were obtained in terms of Kramers-Kronig (KK) relation and Lorenz-Mie theory respectively. Smoke box experimental system was built to validate the effectiveness of the method. The results show that viable and dead fungal spores and mycelia via average mass extinction coefficients can be distinguished. The method can be used to discriminate the bioactivity of microbes and has potential applications in identification, detection, and optical characteristics of viable and dead microbial materials.

Single- and dual-plasmonic induced absorption in a subwavelength end-coupled composite-square cavity.

A plasmonic end-coupled composite-square cavity (CSC) structure is proposed by adding two horizontal and normal slot cavities into a perfect square cavity (PSC) structure that is regarded as a Fabry-Perot resonator. Owing to the interference effect between the bright and dark modes, which is supported by the PSC and the slot cavities, respectively, a single plasmonic induced absorption (PIA) response with large abnormal dispersion is achieved at the former transmission peak in the CSC structure. The induced absorption window can be tuned to the wavelength of the first or second mode by using the horizontal and normal slot cavities. By changing the refractive index of the insulator inside the horizontal slot cavity, dual PIA responses are also obtained in the CSC structure. The performances of the proposed CSC structure are analyzed and investigated by using the finite-difference time-domain method.

[Measurement and analysis on complex refraction indices of pear pollen in infrared band].

Pollen is an important part of bioaerosols, and its complex refractive index is a crucial parameter for study on optical characteristics and detection, identification of bioaerosols. The reflection spectra of pear pollen within the 2. 5 - 15µm waveband were measured by squash method. Based on the measured data, the complex refractive index of pear pollen within the wave-band of 2. 5 to 15 µm was calculated by using Kramers-Kroning (K-K) relation, and calculation deviation about incident angle and different reflectivities at high and low frequencies.were analyzed. The results indicate that 18 degrees angle of incidence and different reflectivities at high and low frequencies have little effect on the results, and it is practicable to calculate the complex refractive index of pollen based on its reflection spectral data. The data of complex refractive index of pollen have some reference value for optical characteristics of pollen, detection and identification of bioaerosols.