A combined AIMD and DFT study of the low-energy radiation responses of GaN.

Although GaN is a promising candidate for semiconductor devices, degradation of GaN-based device performance may occur when the device is bombarded by high-energy charged particles during its application in aerospace, astronomy, and nuclear-related areas. It is thus of great significance to explore the influence of irradiation on the microstructure and electronic properties of GaN and to reveal the internal relationship between the damage mechanisms and physical characteristics. Using a combined density functional theory (DFT) and ab initio molecular dynamics (AIMD) study, we explored the low-energy recoil events in GaN and the effects of point defects on GaN. The threshold displacement energies (Eds) significantly depend on the recoil directions and the primary knock-on atoms. Moreover, the Ed values for nitrogen atoms are smaller than those for gallium atoms, indicating that the displacement of nitrogen dominates under electron irradiation and the created defects are mainly nitrogen vacancies and interstitials. The formation energy of nitrogen vacancies and interstitials is smaller than that for gallium vacancies and interstitials, which is consistent with the AIMD results. Although the created defects improve the elastic compliance of GaN, these radiation damage states deteriorate its ability to resist external compression. Meanwhile, these point defects lead the Debye temperature to decrease and thus increase the thermal expansion coefficients of GaN. As for the electronic properties of defective GaN, the point defects have various effects, i.e., VN (N vacancy), Gaint (Ga interstitial), Nint (N interstitial), and GaN (Ga occupying the N lattice site) defects induce the metallicity, and NGa (N occupying the Ga lattice site) defects decrease the band gap. The presented results provide underlying mechanisms for defect generation in GaN, and advance the fundamental understanding of the radiation resistances of semiconductor materials.

Learning View Synthesis for Desktop Telepresence with Few RGBD Cameras.

Recent telepresence systems have shown significant improvements in quality compared to prior systems. However, they struggle to achieve both low cost and high quality at the same time. In this work, we envision a future where telepresence systems become a commodity and can be installed on typical desktops. To this end, we present a high-quality view synthesis method that uses a cost-effective capture system that consists of commodity hardware accessible to the general public. We propose a neural renderer that uses a few RGBD cameras as input to synthesize novel views of a user and their surroundings. At the core of the renderer is Multi-Layer Point Cloud (MPC), a novel 3D representation that improves reconstruction accuracy by removing non-linear biases in depth cameras. Our temporally-aware renderer further improves the stability of synthesized videos by conditioning on past information. Additionally, we propose Spatial Skip Connections (SSC) to improve image upsampling under limited GPU memory. Experimental results show that our renderer outperforms recent methods in terms of view synthesis quality. Our method generalizes to new users and challenging content (e.g., hand gestures and clothing deformation) without costly per-video optimization, object templates, or heavy pre-processing. The code and dataset will be made available.

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Antibiotic resistance genes (ARGs) have attracted widespread attention as a new global pollutant, mainly due to the abuse of antibiotics. To investigate the diversity of ARGs in three rodent species, we used metagenomic sequencing analysis to analyze the diversity of antibiotic resistance genes of 17 individuals of Apodemus peninsulae and 17 individuals of Myodes rufocanus collected from Mudanfeng, and nine individuals of Apodemus agrarius collected from Sandaoguan. A total of 19 types and 248 subclasses of ARGs were detected in the three rodent species. Seven ARGs showed significant difference and five ARGs showed extremely significant difference between M. rufocanus and A. agrarius. Seven ARGs showed significant difference and four ARGs showed extremely significant difference between A. peninsulae and A. agrarius. Four ARGs showed significant difference and five ARGs showed extremely significant difference between M. rufocanus and A. peninsulae. ARGs showing high abundance in three rodents were macrolides, lincoamides, tetracyclines, and ß-lactams. ARGs were widely distributed in the three rodent species. The significant differences in ARGs among different species might be due to the different distribution areas and their diet differentiation. The study could provide a basis for further studies of ARGs in mice and improve the understanding of the harm of ARGs transmission.

Numerical Simulation and Experimental Verification of Melt-Spinning Parameters' Effects on Multi-Leaf Hollow-Profiled Fiber Preparation.

Multi-leaf hollow-profiled fiber is a complex-shaped fiber with a hollow structure with at least three leaves arranged outside. In this work, spinning processes for the preparation of multi-leaf hollow-profiled fiber with complex cross-section patterns were proposed. Initially, the characteristics and preparation methods of multi-leaf hollow-profiled fibers were analyzed, and the key technologies for their preparation were studied. Further, micro-hole spinnerets were designed, and the numerical simulations of melt flow in the spinning channel were performed. Then, the preparation of six-leaf hollow profiled fibers was carried out to study the formation of the cross-sections. Finally, as an extension and application, an experimental verification of the melt spinning parameters' effects on eight-leaf hollow fiber preparation was conducted. From the results of the spinning experiments, it was found that when the volume flow rate of a single hole increased from 2.33 × 10-8 m3/s to 3.33 × 10-8 m3/s, the profile degree of the spun fiber increased from 30.93% to a maximum value of 40.99%. Furthermore, when the cooling speed increased from 0.6 m/s to 1 m/s, the profile degree increased from 29.56% to 41.63%. When the initial blowing height increased from 80 mm to 140 mm, the profile degree decreased from 40.99% to 27.13%. When the spinning temperature increased from 285 °C to 290 °C, the profile degree decreased from 40.99% to 38.56%. However, the winding speed had an insignificant effect on the cross-sectional shape of the spun fibers. Moreover, the spun fibers showed good performance and a natural three-dimensional crimp function.

Identification of Crucial Genes and Regulatory Pathways in Alfalfa against Fusarium Root Rot.

Fusarium root rot, caused by Fusarium spp. in alfalfa (Medicago sativa L.), adversely impacts alfalfa by diminishing plant quality and yield, resulting in substantial losses within the industry. The most effective strategy for controlling alfalfa Fusarium root rot is planting disease-resistant varieties. Therefore, gaining a comprehensive understanding of the mechanisms underlying alfalfa's resistance to Fusarium root rot is imperative. In this study, we observed the infection process on alfalfa seedling roots infected by Fusarium acuminatum strain HM29-05, which is labeled with green fluorescent protein (GFP). Two alfalfa varieties, namely, the resistant 'Kangsai' and the susceptible 'Zhongmu No. 1', were examined to assess various physiological and biochemical activities at 0, 2, and 3 days post inoculation (dpi). Transcriptome sequencing of the inoculated resistant and susceptible alfalfa varieties were conducted, and the potential functions and signaling pathways of differentially expressed genes (DEGs) were analyzed through gene ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Meanwhile, a DEG co-expression network was constructed though the weighted gene correlation network analysis (WGCNA) algorithm. Our results revealed significant alterations in soluble sugar, soluble protein, and malondialdehyde (MDA) contents in both the 'Kangsai' and 'Zhongmu No. 1' varieties following the inoculation of F. acuminatum. WGCNA analysis showed the involvement of various enzyme and transcription factor families related to plant growth and disease resistance, including cytochrome P450, MYB, ERF, NAC, and bZIP. These findings not only provided valuable data for further verification of gene functions but also served as a reference for the deeper explorations between plants and pathogens.

FineFDR: Fine-grained Taxonomy-specific False Discovery Rates Control in Metaproteomics.

Microbial community proteomics, also termed metaproteomics, investigates all proteins expressed by a microbiota. Tandem mass spectrometry (MS/MS) is the typical method for identifying proteins in metaproteomics, which involves searching the mass spectra against a protein sequence database. A major post-analysis step is controlling the false discovery rate (FDR), i.e., the ratio of false positives to the total number of annotations. The current popular target-decoy FDR estimation method treats all the peptides and proteins equally and overlooks that they could have varied probabilities of being identified. In this study, we report FineFDR, a framework for FDR assessment at fine-grained levels with taxonomy information considered. FineFDR groups the identified peptide-spectrum matches, peptides, and proteins from different taxonomic units and estimates the FDR in each group separately. Empirical experiments on the simulated and real-world data sets demonstrate that our FineFDR achieved higher precision and more peptide and protein identifications when compared to the state-of-the-art methods, such as Comet, Percolator, TIDD, and Tailor. FineFDR is freely available under the GNU GPL license at https://github.com/Biocomputing-Research-Group/FDR.

Effects of LED illumination spectra on glucosinolate and sulforaphane accumulation in broccoli seedlings.

Glucosinolates (GSLs) are well known for plant defense and human nutrition. In this study, broccoli seedlings were illuminated under different LED light, including white, red, blue, and 75% red + 25% blue (200 mmol·m-2·s-1) for 4 weeks to investigate the effects of LED light on GSLs and sulforaphane biosynthesis. Results showed that red light promoted GSL biosynthesis and sulforaphane accumulation because red light could induce SOT18 expression to advance aliphatic GSLs biosynthesis, whereas the high tryptophan content and the upregulation of CYP79B2, CYP79B3, and CYP83B1 were attributed to indole GSL biosynthesis. Low-level methionine content and downregulated SOT18 were the main factors inhibiting GSLs and sulforaphane accumulation under blue LED illumination. BoHY5 gene expression was induced significantly and the yeast one-hybrid assay demonstrated BoHY5 could bind to SOT18 promoter. Consequently, BoHY5 inhibited SOT18 expression, and played a negative role in the GSL biosynthetic network.