Surface plasmon polaritons assisted diffraction in periodic subwavelength holes of metal films with reduced interplane coupling

Metal films grown on Si wafer perforated with a periodic array of subwavelength holes have been fabricated and anomalous enhanced transmission in the mid-infrared regime has been observed. High order transmission peaks up to Si(2,2) are clearly revealed due to the large dielectric constant contrast of the dielectrics at the opposite interfaces. Si(1,1) peak splits at oblique incidence both in TE and TM polarization, which confirms that anomalous enhanced transmission is a surface plasmon polaritons (SPPs) assisted diffraction phenomenon. Theoretical transmission spectra agree excellently with the experimental results and confirm the role of SPPs diffraction by the lattice.Comment: 4 pages, 5 figures, 26 reference

A Hyper-network Based End-to-end Visual Servoing with Arbitrary Desired Poses

Recently, several works achieve end-to-end visual servoing (VS) for robotic manipulation by replacing traditional controller with differentiable neural networks, but lose the ability to servo arbitrary desired poses. This letter proposes a differentiable architecture for arbitrary pose servoing: a hyper-network based neural controller (HPN-NC). To achieve this, HPN-NC consists of a hyper net and a low-level controller, where the hyper net learns to generate the parameters of the low-level controller and the controller uses the 2D keypoints error for control like traditional image-based visual servoing (IBVS). HPN-NC can complete 6 degree of freedom visual servoing with large initial offset. Taking advantage of the fully differentiable nature of HPN-NC, we provide a three-stage training procedure to servo real world objects. With self-supervised end-to-end training, the performance of the integrated model can be further improved in unseen scenes and the amount of manual annotations can be significantly reduced

Heterologous Expression and Enzymatic Characterization of Ferulic Esterase from Aspergillus terreus and Its Application in the Preparation of Ferulic Acid

To improve the expression level of ferulic esterase (FAE), the FAE encoding gene from Aspergillus terreus was heterologously expressed in Pichia pastoris. The expression level of FAE in the recombinant strain was (17.38 ± 0.34) U/mL, which was approximately 35 times as high as that of the original strain. The molecular mass of the recombinant A. terreus FAE (rAtFAE) was approximately 39 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Enzymatic characterization showed that the optimal pH of rAtFAE was 6.0, the optimal reaction temperature was 50 ℃, and the kcat/Km values measured with methyl caffeic acid, methyl coumarinate, methyl ferulic acid and methyl sinakoate as substrates were 255, 237, 112.64 and 96.85 L/(mol·min), respectively. The combination of rAtFAE and xylanase showed a good synergistic effect in enhancing the release of ferulic acid from wheat bran up to (1 876.45 ± 30.05) μg/g

Fabrication of Spin-Transfer Nano-Oscillator by Colloidal Lithography

We fabricate nanoscale spin-transfer oscillators (STOs) by utilizing colloidal nanoparticles as a lithographic mask. By this approach, high quality STO devices can be fabricated, and as an example the fabricated STO devices using MgO magnetic tunnel junction as the basic cell exhibit current-induced microwave emission with a large frequency tunability of 0.22 GHz/mA. Compared to the conventional approaches that involve a step of defining nanoscale elements by means of electron beam lithography, which is not readily available for many groups, our strategy for STO fabrication does not require the sophisticated equipment (~ million dollars per unit) and expensive lithography resist, while being cost-effective and easy to use in laboratory level. This will accelerate efforts to implement STO into on-chip integrated high-radio frequency applications

Portable microfluidic devices for monitoring antibiotic resistance genes in wastewater

Antibiotic resistance genes (ARGs) pose serious threats to environmental and public health, and monitoring ARGs in wastewater is a growing need because wastewater is an important source. Microfluidic devices can integrate basic functional units involved in sample assays on a small chip, through the precise control and manipulation of micro/nanofluids in micro/nanoscale spaces, demonstrating the great potential of ARGs detection in wastewater. Here, we (1) summarize the state of the art in microfluidics for recognizing ARGs, (2) determine the strengths and weaknesses of portable microfluidic chips, and (3) assess the potential of portable microfluidic chips to detect ARGs in wastewater. Isothermal nucleic acid amplification and CRISPR/Cas are two commonly used identification elements for the microfluidic detection of ARGs. The former has better sensitivity due to amplification, but false positives due to inappropriate primer design and contamination; the latter has better specificity. The combination of the two can achieve complementarity to a certain extent. Compared with traditional microfluidic chips, low-cost and biocompatible paper-based microfluidics is a very attractive test for ARGs, whose fluid flow in paper does not require external force, but it is weaker in terms of repeatability and high-throughput detection. Due to that only a handful of portable microfluidics detect ARGs in wastewater, fabricating high-throughput microfluidic chips, developing and optimizing recognition techniques for the highly selective and sensitive identification and quantification of a wide range of ARGs in complex wastewater matrices are needed.This work was supported by the National Natural Science Foundation of China (42377456), Guizhou Provincial Science and Technology Projects (Qiankehe Jichu-ZK [2022] Yiban 565, Qiankehe Platform Talents-GCC [2023] 046), the Hebei Provincial Science and Technology Projects (24291703Z), and the Youth Innovation Promotion Association CAS (2023415), CAS-ANSO Fellowship (CAS-ANSO-FS-2024–34).Microchimica Act

Automatic Assessment of OCT Skin Thickness in Mice Based on Transfer Learning and Attention Mechanisms

Optical coherence tomography (OCT) is characterized by high resolution and noninvasiveness; thus, it has been widely used to analyze skin tissues in recent years. Previous studies have evaluated skin OCT images using traditional algorithms with low accuracy for complex tissue structure images. Although a few studies have used deep learning methods to assess tissue structure in OCT images, they lack quantitative assess-ment of deeper skin tissue thickness and are limited to the epidermal layer. Thus, in the present study, we proposed an automated segmentation and quantitative evaluation method. The skin OCT images were first pre-processed, and the attention mechanism was added to U-Net based on transfer learning to segment the images and quantify the thickness of mouse skin tissue structure. The results showed that U-Net combined with the coordinate attention (CA) mechanism had better segmentation performance with 93.94% mean intersection of union (MIoU) value and 96.99% Dice similarity coefficient; the segmentation errors were 0.6 μm, 2.2 μm, 3.8 μm, and 6.0 μm for the epidermis layer, subcutaneous fat layer, muscle fascia layer, and the overall skin tissue structure of mice, respectively. The overall skin tissue thickness of the four mice were 235 ± 20 μm, 264 ± 42 μm, 275 ± 40 μm, and 774 ± 91 μm, respectively. The present study provides a rapid and accurate method for the automated measurement of skin tissue thickness