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We propose a seawater salinity sensor array based on a micro/nanofiber Bragg grating structures, which allows for the simultaneous measurement of temperature and salinity. The proposed sensing structure is fabricated through a process involving optical fiber tapering, femtosecond laser inscription, and chemical etching. The equivalent refractive index (RI) of this sensor structure is influenced by the surrounding RI, resulting in a Bragg characteristic wavelength shift that can be used for salinity sensing. The experimental results show that the salinity sensitivity for two cascaded sensor arrays is 8.39 pm/‰ and 7.71 pm/‰, while the temperature sensitivity is 8.28 pm/°C and 8.03 pm/°C, respectively. This sensor structure is compact, exhibits excellent linearity, and offers good repeatability. It holds great potential for applications in seawater environmental monitoring and quantitative studies of seawater dispersion characteristics.

The double-skin roof has been applied in the design of modern granaries for energy saving. Compared with the ordinary parallel double plate, the double skin composed of an inclined upper plate can effectively improve the situation of a “hot roof” through an air exhaust, thus having better thermal performance. To study the advantages of a double-skin roof with an inclined upper plate and the effects of physical parameters on convective heat transfer, an experimental and numerical study was carried out in this work. According to the actual size of the grain depot in the application, an experimental setup was established based on the similarity theory with a scale of 1:28 to the real one. The double-skin roof consists of two plates: the lower one was used as the original surface of the depot, and the other was suspended above. For comparison, the two flat plates were arranged to be parallel or inclined. Changeable parameters included the flow rate through the air gap between the double plates, the thickness of the air gap, and the reducing ratio. Other parameters, such as the air temperature, were the same, and the influence of the above factors on the performance of the double-skin roof was studied. The results showed that both the flow rate and the air gap’s thickness can affect the roof’s thermal performance. Under the optimal working conditions in the parallel mode (with an air gap of 0.07 m and a flow rate of 60 m3/h), the temperature increment at the surface of the grain bulk was 1.88 °C, which was lower than the mode without a suspended upper plate. Moreover, the inclined design of the upper plate increased the air velocity along the flowing direction, which strengthened the convection at the outlet and, thus, improved the average thermal performance of the opened roof. The inclined mode controlled the temperature at the grain bulk surface within 24 °C, which dropped by 1 °C compared with the parallel mode under the same working conditions. In addition, a geometric model of the experimental setup was created, and the grid was divided through the software ANSYS ICEM 15.0 The convection term in the conservation equation was discretized with the QUICK scheme, and the solution for the flow field was obtained using the SIMPLE algorithm. The experimental data were used as the input profile for the model, and the numerical results were compared with the experimental results to verify the accuracy of the model. The average and the maximum errors were between 3% and 8.9%, respectively. The simulation results indicated the effects of the reducing ratio on the roof thermal performance with the analysis of the Rayleigh number and the Nusselt number. In the inclined mode, a smaller reducing ratio was beneficial to air convection. With a reducing ratio of about 0.5, the outlet velocity of the roof was higher by 30.6%, resulting in a larger local Nu number and better thermal performance. When the dimensionless length was in a range of 0.34~0.37, the Nu number was increasing. Near the inlet of the double-skin roof, the Nu number increased with the Ra number, given a dimensionless length of below 0.15. Therefore, the ventilated double-skin roof with an inclined upper plate is recommended for roof reconstruction design because of its advanced air convection.

Although the study on the regulatory mechanism of endothelial differentiation from the perspective of development provides references for endothelial cell (EC) derivation from pluripotent stem cells, incomplete reprogramming and donor-specific epigenetic memory are still thought to be the obstacles of iPSCs for clinical application. Thus, it is necessary to establish a stable iPSC-EC induction system and investigate the regulatory mechanism of endothelial differentiation. Based on a single-layer culture system, we successfully obtained ECs from porcine iPSCs (piPSCs). In vitro, the derived piPSC-ECs formed microvessel-like structures along 3D gelatin scaffolds. Under pathological conditions, the piPSC-ECs functioned on hindlimb ischemia repair by promoting blood vessel formation. To elucidate the molecular events essential for endothelial differentiation in our model, genome-wide transcriptional profile analysis was conducted, and we found that during piPSC-EC derivation, the synthesis and secretion level of TGF-β as well as the phosphorylation level of Smad2/3 changed dynamically. TGF-β-Smad2/3 signaling activation promoted mesoderm formation and prevented endothelial differentiation. Understanding the regulatory mechanism of iPSC-EC derivation not only paves the way for further optimization, but also provides reference for establishing a cardiovascular drug screening platform and revealing the molecular mechanism of endothelial dysfunction.

Crustin are a family of antimicrobial peptides that play an important role in protecting against pathogens infection in the innate immune system of crustaceans. Previously, we identified several novel types of crustins, including type VI and type VII crustins. However, their immune functions were still unclear. In the present study, the immune function of type VII crustin LvCrustinVII were investigated in Litopenaeus vannamei. LvCrustinVII was wildly expressed in all tested tissues, with relatively high expression levels in hepatopancreas, epidermis and lymphoid organ. Upon Vibrio parahaemolyticus infection, LvCrustinVII was significantly upregulated in hepatopancreas. Recombinant LvCrustinVII (rLvCrustinVII) showed strong inhibitory activities against Gram-negative bacteria Vibrio harveyi and V. parahaemolyticus, while weak activities against the Gram-positive bacteria Staphylococcus aureus. Binding assay showed that rLvCrustinVII could bind strongly to V. harveyi and V. parahaemolyticus, as well as the cell wall components Glu, LPS and PGN. In the presence of Ca2+, rLvCrustinVII could agglutinate V. parahaemolyticus and enhance hemocyte phagocytosis. The present data partially illustrate the immune function of LvCrustinVII, which enrich our understanding on the functional mechanisms of crustins and provide useful information for application of this kind of antimicrobial peptides.

In the recent decades, development of agricultural and human settlements have severely affected wetlands on the China-side of the Amur River Basin (CARB). A long-term holistic view of spatio-temporal variations of the wetlands on the CARB is essential for supporting sustainable conservation of wetlands in this region. In this study, a training sample migration method along with Random Forest classifier were adopted to map wetland and other land covers from two key seasons image collections. The proposed classification method was applied to Landsat images, and a 30-m resolution dataset was obtained, which reflected the dynamic changes of historical wetland distribution on the CARB region from 1990 to 2010. As the accuracy assessments showed, land cover maps of the CARB had high accuracies. The classification results indicated that the wetland area decreased from 89,432 km2 to 75,061 km2 between 1990 and 2010, with a net loss of 16%, which was mainly converted to paddy field and dry farmland, and the changes were most obvious in Sanjiang Plain and Songnen Plain. This suggests that agricultural activities are the main cause of wetland loss. The results can provide reliable information for the research on wetland management and sustainable development of the society and economy in the CARB.

A gain slab configuration with a low thermally induced wavefront distortion, which is based on heating the edge by the cladding layer, is proposed. The gain slab will be applied to a helium-cooled Nd: glass multislab laser amplifier with an output of 100 J at a repetition rate of 10 Hz. Additionally, a 3D numerical simulation model is developed to analyze the thermo-optic effects in the gain slab. Some parameters, including the absorption coefficient (α) of the cladding layer, the shape of the pump beam, and the gap between the pump area and absorbing cladding layer, are optimized to eliminate the thermo-optic effects. The results indicate that the peak-to-valley (P-V) of the thermally induced wavefront distortion of the specific gain slab can be reduced by 61% if other parameters remain constant.

This paper reports on a Joule-level multi-pass laser amplification device with diode end-pumped square-rod neodymium glass (Nd:glass) bonded to K9 glass. The device generated 1.17 J pulse energy at 1 Hz and 1053 nm. The optical-to-optical efficiency was 13.01%, and the effective energy extraction efficiency was 44.23%. Comparing Nd:glass of the same specification without K9 glass under the same conditions, the thermal wave aberration of the former was 85.71% of that of the latter, which is 0.78 um. The near-field modulation degree at the highest energy output was 1.42 within 90% of the spot, and the far-field energy concentration was 81.88% within the 2.5-fold diffraction limit. The Nd:glass bonding method of the square rod is relatively novel in laser amplification systems pumped by the diode end face and can be further studied in future works.

In this paper, a model to predict the thermal effects in a flashlamp-pumped direct-liquid-cooled split-disk Nd:LuAG ceramic laser amplifier has been presented. In addition to pumping distribution, the model calculates thermal-induced wavefront aberration as a function of temperature, thermal stress and thermal deformation in the gain medium. Experimental measurements are carried out to assess the accuracy of the model. We expect that this study will assist in the design and optimization of high-energy lasers operated at repetition rate.

The characterization of a laser diode (LD)-pumped neodymium-doped silica glass (NDSG) laser is here described. The gain performance and wavefront distortion were measured, and the thermal toughness and uniformity distribution of the material were experimentally observed. At a pumping frequency of 1 Hz and energy 7.79 J, a small-signal gain of 1.16 was measured, and the wavefront distortion reached 2.67 λ (wavelength λ = 1053 nm). At a pumping frequency of 25 Hz with 194 W power, the NDSG was still not cracked, which is consistent with its high thermal shock parameter. However, the material uniformity was relatively poor. These results indicate good prospects for the application of NDSG lasers at high energy and high repetition frequency, but the gain performance, uniformity, and other aspects affected by the manufacturing process need to be improved.

The influence of driving conditions on the phase-modulation ability of an optically addressable spatial-light modulator (OASLM) is investigated using an equivalent circuit method and a system for measuring wave-front modulation that uses a phase-unwrapping data-processing method, and is constructed with a charge-coupled device and wave-front sensor. 1λ peak-to-valley phase change for a 1053 nm laser beam is acquired with the home-made OASLM at the optimal driving voltage of 14 V at 200 Hz. The detection system for wave-front modulation has a spatial resolution of 200 µm for binary images and a minimum distinguishable contrast of 1 mm. On-line phase modulation with feedback control can be acquired with the OASLM and the corresponding measuring system.

K9 glass is a classical transparent material widely used in high-power optical systems due to its high-temperature resistance. However, the precision machining of K9 glass is difficult. The laser processing method, characterized by being non-contact, having a small heat-affected zone, and having high processing precision, is commonly employed for processing intricate structures. In this study, the vector diffraction model is employed to simulate the internal electric field inside the material when focused by objective lenses with varying numerical apertures. Furthermore, the temperature field is simulated. The simulation considered the nonlinear absorption of the material, the stretching of the focal dot due to spherical aberration, and the energy loss of the laser during the focusing process. The experiment indicated that the ablated area consists of numerous small, ablated dots and that multiple ablated areas emerged under an NA of 0.6. This study can provide valuable references for the research of the interaction between lasers and glass materials.

In response to the growing demand for railway obstacle monitoring, lidar technology has emerged as an up-and-coming solution. In this study, we developed a mechanical 3D lidar system and meticulously calibrated the point cloud transformation to monitor specific areas precisely. Based on this foundation, we have devised a novel set of algorithms for obstacle detection within point clouds. These algorithms encompass three key steps: (a) the segmentation of ground point clouds and extraction of track point clouds using our RS-Lo-RANSAC (region select Lo-RANSAC) algorithm; (b) the registration of the BP (background point cloud) and FP (foreground point cloud) via an improved Robust ICP algorithm; and (c) obstacle recognition based on the VFOR (voxel-based feature obstacle recognition) algorithm from the fused point clouds. This set of algorithms has demonstrated robustness and operational efficiency in our experiments on a dataset obtained from an experimental field. Notably, it enables monitoring obstacles with dimensions of 15 cm × 15 cm × 15 cm. Overall, our study showcases the immense potential of lidar technology in railway obstacle monitoring, presenting a promising solution to enhance safety in this field.

This article presents a high-precision obstacle detection algorithm using 3D mechanical LiDAR to meet railway safety requirements. To address the potential errors in the point cloud, we propose a calibration method based on projection and a novel rail extraction algorithm that effectively handles terrain variations and preserves the point cloud characteristics of the track area. We address the limitations of the traditional process involving fixed Euclidean thresholds by proposing a modulation function based on directional density variations to adjust the threshold dynamically. Finally, using PCA and local-ICP, we conduct feature analysis and classification of the clustered data to obtain the obstacle clusters. We conducted continuous experiments on the testing site, and the results showed that our system and algorithm achieved an STDR (stable detection rate) of over 95% for obstacles with a size of 15 cm × 15 cm × 15 cm in the range of ±25 m; at the same time, for obstacles of 10 cm × 10 cm × 10 cm, an STDR of over 80% was achieved within a range of ±20 m. This research provides a possible solution and approach for railway security via obstacle detection.

Silicon Carbide (SiC) is the predominant substrate material for optoelectronic-integrated devices. However, it challenges the wafer-slicing process because of its high hardness, brittleness, and other material characteristics. Laser processing has gained prominence as the primary method, leveraging its merits of high efficiency, precision, and micro-destructiveness. In this study, a finite element method is applied to calculate the temperature field distribution resulting from the electric field of a Gaussian beam. The simulation considers laser propagation inside 4H-SiC, non-linear absorption, and spherical aberration induced by the refractive index of the material. The influence of laser pulse energy and focusing depth are considered. The results indicate that the modification depths decrease with the increasing focusing depth. With the increase of laser pulse energy, the depth of the modification layer increases continuously. Moreover, an experimental setup has been devised to furnish valuable references in validating the proposed model.

Biofilms in reactors usually grow on impermeable surfaces, and the mass transfer of nutrients in biofilms is mainly driven by diffusion, which is inefficient especially for thick biofilms. In this study, permeable materials (i.e., nylon meshes) were used as biocarriers in a biofilm reactor, and their performance was evaluated and compared with the commercial biocarriers (PE08 and PE10) used for treating slightly polluted water. The results indicate that the mesh-based bioreactor achieved complete nitrification faster than the commercial biocarriers, with a more stable and better effluent quality during long-term operation. At a two-hour hydraulic retention time, the average effluent ammonia (NH4+-N) and nitrite (NO2−-N) concentrations during the stabilized phase were 0.97 ± 0.79 and 0.61 ± 0.32 mg-N, respectively, which are significantly lower than those with commercial carriers. The estimated specific surface area activities for the mesh, PE08, and PE10 carriers were 1620, 769, and 1300 mg-N/(m2·d)), respectively. The biofilms formed on the nylon mesh were porous, while they were compact and nonporous on the PE carriers. Water with substrates might pass through the porous biofilms formed on the meshes, which could enhance mass transfer and result in a better and more stable treatment performance.

High temperatures severely affect plant growth and pose a threat to global crop production. Heat causes the accumulation of misfolded proteins in the endoplasmic reticulum(ER), as well as triggering the heat-shock response (HSR) in the cytosol and the unfolded protein response (UPR) in the ER. Excessive misfolded proteins undergo further degradation through ER-associated degradation (ERAD). Although much research on the plant heat stress response has been conducted, the regulation of ER-localized proteins has not been well-studied thus far. We isolated the microsome fraction from heat-treated and untreated maize seedlings and performed proteome and ubiquitylome analyses. Of the 8306 total proteins detected in the proteomics analysis, 1675 proteins were significantly up-regulated and 708 proteins were significantly down-regulated. Global ubiquitination analysis revealed 1780 proteins with at least one ubiquitination site. Motif analysis revealed that alanine and glycine are the preferred amino acids upstream and downstream of ubiquitinated lysine sites. ERAD components were found to be hyper-ubiquitinated after heat treatment, implying the feedback regulation of ERAD activity through protein degradation.

This study mainly uses PFC (particle follow code) to simulate the void characteristics of permeable asphalt mixture, and uses these to simulate the silting process. Then, a tire drop test was used to evaluate the noise reduction performance of permeable asphalt concrete. Finally, a self-made ring rutting test machine was used to simulate the silting process. Through experiments, the following conclusions were obtained: 1. The critical size of the sludge particle size is 0.3 mm–0.6 mm. 2. The quality of the water-permeable asphalt concrete specimens increased by 13% before and after silting, and the porosity of the specimens finally decreased from about 20% to about 8%. The water-permeable function only retained less than 20% of the original, and the water-permeable function was basically lost. 3. By measuring the road noise detection, it was found that the road noise is directly proportional to the degree of blockage of the permeable road. Compared with the original road with a perfect permeable function, the road noise of the completely blocked road increased by about 4 decibels. This study reveals the silting process of permeable asphalt mixture and the key particle size of the silt, which is of great significance for the detection, cleaning and maintenance of permeable asphalt pavements.