Hierarchical attention-guided multiscale aggregation network for infrared small target detection.

All man-made flying objects in the sky, ships in the ocean can be regarded as small infrared targets, and the method of tracking them has been received widespread attention in recent years. In search of a further efficient method for infrared small target recognition, we propose a hierarchical attention-guided multiscale aggregation network (HAMANet) in this thesis. The proposed HAMANet mainly consists of a compound guide multilayer perceptron (CG-MLP) block embedded in the backbone net, a spatial-interactive attention module (SiAM), a pixel-interactive attention module (PiAM) and a contextual fusion module (CFM). The CG-MLP marked the width-axis, height-axis, and channel-axis, which can result in a better segmentation effect while reducing computational complexity. SiAM improves global semantic information exchange by increasing the connections between different channels, while PiAM changes the extraction of local key information features by enhancing information exchange at the pixel level. CFM fuses low-level positional information and high-level channel information of the target through coding to improve network stability and target feature utilization. Compared with other state-of-the-art methods on public infrared small target datasets, the results show that our proposed HAMANet has high detection accuracy and a low false-alarm rate.

Optimization of Coupling Efficiency in Butterfly Optical Communication Laser Based on Chaotic Adaptive Seeker Optimization Algorithm.

A chaotic adaptive seeker optimization algorithm (CASOA) is proposed in this study to improve the coupling efficiency and accuracy of a butterfly optical communication laser. It primarily relies on chaotic disturbance to improve seeker search performance. The chaotic disturbance enables the algorithm to jump out from local extremes. Furthermore, chaos is associated with a novel strategy for optimizing search paths with a small population. A simulation and experiment are conducted to demonstrate that the CASOA with a few seekers has an excellent search success rate with few iterations in the coupling alignment. These results indicate that the proposed CASOA can reliably improve the coupling accuracy and efficiency of laser diodes and single-mode fibers.

Optical power auto-alignment method with eugenics sorting for enhancing the alignment speed and robustness of fiber-grating couplers.

To auto-couple optical devices, a simple but effective method must have a high success rate, fast scanning speed, and high stability. For coupling accuracy, swarm intelligence algorithms set a large number of particles to find the optimal point, which can introduce accelerated geometric errors in practical engineering. In this study, we proposed a method for auto-alignment between single-mode fibers and grating couplers using the particle swarm optimization algorithm, which introduces a chaotic mapping and eugenics mechanism. With the help of chaotic mapping and eugenics mechanisms, the scanning speed and robustness increased remarkably. A series of simulations and experiments showed that this method could increase the efficiency and robustness by 90% and 50%, respectively, compared to the basic swarm intelligence algorithm.

Panoramic transcriptome analysis and functional screening of long noncoding RNAs in mouse spermatogenesis.

Long noncoding RNAs (lncRNAs) have emerged as diverse functional regulators involved in mammalian development; however, large-scale functional investigation of lncRNAs in mammalian spermatogenesis in vivo is lacking. Here, we delineated the global lncRNA expression landscape in mouse spermatogenesis and identified 968 germ cell signature lncRNAs. By combining bioinformatics and functional screening, we identified three functional lncRNAs (Gm4665, 1700027A15Rik, and 1700052I22Rik) that directly influence spermatogenesis in vivo. Knocking down Gm4665 hampered the development of round spermatids into elongating spermatids and disrupted key spermatogenic gene expression. Mechanistically, lncRNA Gm4665 localized in the nucleus of round spermatids and occupied the genomic regulatory region of important spermatogenic genes including Ip6k1 and Akap3 These findings provide a valuable resource and framework for future functional analysis of lncRNAs in spermatogenesis and their potential roles in other biological processes.

A long noncoding RNA binding to QKI-5 regulates germ cell apoptosis via p38 MAPK signaling pathway.

Spermatogenesis is the complex process of male germline development and requires coordinated interactions by multiple gene products that undergo strict developmental regulations. Increasing evidence has suggested that a number of long noncoding RNAs (lncRNAs) may function as important regulatory molecules in various physiological and pathological processes by binding to specific proteins. Here, we identified a subset of QKI-5-binding lncRNAs in the mouse testis through the integrated analyses of RNA immunoprecipitation (RIP)-microarray and biological verification. Among the lncRNAs, we revealed that NONMMUT074098.2 (Lnc10), which was highly expressed in the spermatogonia and spermatocytes of the testis, interacted with QKI-5. Furthermore, Lnc10 depletion promoted germ cell apoptosis via the activation of p38 MAPK, whereas the simultaneous knockdown of QKI-5 could rescue the apoptotic phenotype and the activation of p38 MAPK, which were induced by the loss of Lnc10. These data indicated that the Lnc10-QKI-5 interaction was associated with the regulatory roles of QKI-5 and that the Lnc10-QKI-5 interaction inhibited the regulation of QKI-5 on the downstream p38 MAPK signaling pathway. Additionally, we functionally characterized the biological roles of Lnc10 and found that the knockdown of Lnc10 promoted the apoptosis of spermatogenic cells in vivo; this suggested that Lnc10 had an important biological role in mouse spermatogenesis. Thus, our study provides a potential strategy to investigate the biological significance of lncRNA-RBP interactions during male germline development.

The Study on Mechanical Strength of Titanium-Aluminum Dissimilar Butt Joints by Laser Welding-Brazing Process.

Laser welding⁻brazing of 5A06 aluminum to Ti6Al4V titanium in a butt configuration was carried out to discuss the influences of welding parameters on dissimilar joint properties. The effects of laser offset, welding speed, and laser power on the spreading length of the molten aluminum liquid, interface fracture zone width (IFZW), fracture roughness, intermetallic compounds (IMCs) thickness, and tensile strength were also investigated. The microstructure and fracture of the joint were also studied. The results show that the tensile strength of the joint is not only influenced by the thickness and type of IMCs, but also influenced by the spreading ability of the aluminum liquid, the fracture area broken at the Ti/fusing zone (FZ) interface, and the relative area of the brittle and ductile fracture in FZ. A dissimilar butt joint with an IMC thickness of 2.79 µm was obtained by adjusting the laser offset, welding speed, and laser power to 500 µm, 11 mm/s and 1130 W, respectively. The maximum tensile strength of the joint was up to 183 MPa, which is equivalent to 83% of the tensile strength of the 5A06 aluminum alloy.

Rnf138 deficiency promotes apoptosis of spermatogonia in juvenile male mice.

Spermatogenesis, the process by which haploid sperm cells are produced from a diploid precursor cell, is essential for sexual reproduction. Here, we report that RING-finger protein 138 (Rnf138) is highly expressed in testes, especially in spermatogonia and spermatocytes. The role of Rnf138 in spermatogenesis was examined using a Rnf138-knockout mouse model. Rnf138 deficiency resulted in increased apoptosis in spermatogenic cells, loss of proliferative spermatogonia, delayed development of spermatozoa and impaired fertility. The proportion of PLZF+Ki67+ cells within the PLZF+ population decreased in the knockout mice. The phenotype was further assessed by RNA-sequencing (RNA-seq), which determined that the expression levels of many genes involved in spermatogenesis were altered in the testis of Rnf138-knockout mice. Thus, Rnf138 deficiency promotes the apoptosis of spermatogenic cells, which may have been caused by the aberrant proliferation of spermatogonia in mouse testis development.