分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2022-03-24 合作期刊: 《干旱区科学》
摘要： Abstract: Vegetation near-soil-surface factors can protect topsoil from erosion, however, their contributions to the reduction of soil erosion, especially under natural rainfall events, have not been systematically recognized. This study was performed to quantify the effects of near-soil-surface factors on runoff and sediment under natural rainfall events on grasslands dominated by Bothriochloa ischaemum (Linn.) Keng (BI grassland) and Artemisia gmelinii Thunb. (AG grassland) in two typical watersheds on the Loess Plateau, China in 2018. By successive removal of the plant canopy, litter, biological soil crusts (BSCs) and plant roots, we established five treatments including plant roots, plant roots+BSCs, plant roots+BSCs+litter, intact grassland and bare land in each grassland type. In total, twenty runoff plots (5 m3 m) with similar slopes and aspects were constructed in the two types of grasslands. Results showed that plant canopy, litter and roots reduced runoff, while BSCs, which swelled in the presence of water, increased runoff. In contrast, all of these factors reduced sediment yield. In addition, the reductions in runoff and sediment yield increased with I30 (maximum 30-min rainfall intensity) for each vegetation near-soil-surface factor except for BSCs. Among these factors, plant canopy had the largest contribution to runoff reduction, accounting for 48.8% and 39.9% in the BI and AG grasslands, respectively. The contributions of these vegetation near-soil-surface factors to sediment yield reduction were similar (21.3%29.9%) in the two types of grasslands except for BSCs in the AG grassland (10.3%). The total reduction in runoff in the BI grassland (70.8%) was greater than that in the AG grassland (53.1%), while the reduction in sediment yield was almost the same in both grasslands (97.4% and 96.7%). In conclusion, according to the effects of different vegetation near-soil-surface factors on runoff and sediment production, our results may provide more complete insight and scientific basis into the effects of various vegetation related factors in controlling soil erosion.
分类： 农、林、牧、渔 >> 农、林、牧、渔业科学其他学科 提交时间： 2024-06-17 合作期刊: 《智慧农业（中英文）》
摘要： ［目的/意义］传统的小麦倒伏检测方法需要人工进行田间观测和记录，这种方法存在主观、效率低、劳 动强度大等问题，难以满足大规模的小麦倒伏检测的需求。基于深度学习的小麦倒伏检测技术虽已在一定程度上 得到应用，但普遍局限于对小麦单一发育阶段的倒伏识别，而倒伏可能发生在小麦生长的各个时期，不同时期倒 伏特征变化复杂，这给模型特征捕捉能力带来考验。本研究旨在探索一种基于深度学习技术的多生育期小麦倒伏 区域检测方法。［方法］用无人机采集小麦灌浆期、早熟期、晚熟期这三个关键生长阶段的RGB图像，通过数据 增强等技术构建出多生育期小麦倒伏数据集。提出一种小麦倒伏提取模型Lodging2Former，该模型在Mask2Former 的基础上加以改进，引入分层交互式特征金字塔网络（Hierarchical Interactive Feature Pyramid Network, HI-FPN ）， 用于提高模型在复杂田间背景干扰下对于多个生长阶段小麦倒伏特征的捕捉能力。［结果和讨论］所提出的Lodg⁃ ing2Former模型相较于现存的多种主流算法，如Mask R-CNN （Mask Region-Based Convolutional Neural Network）、 SOLOv2（Segmenting Objects by Locations, Version 2） 以及Mask2Former，在平均精度均值（mean Average Precision, mAP） 上展现出显著优势。在阈值分别为0.5、0.75以及0.5~0.95的条件下，模型的mAP值分别达到了79.5%、 40.2%和43.4%，相比Mask2Former模型，mAP性能提升了1.3%~4.3%。［结论］提出的HI-FPN网络可以有效利用 图像中的上下文语义和细节信息，通过提取丰富的多尺度特征，增强了模型对小麦在不同生长阶段倒伏区域的检 测能力，证实了HI-FPN在多生育期小麦倒伏检测中的应用潜力和价值。
分类： 生物学 >> 病毒学 提交时间： 2020-02-25
Xia, Jia
Lu, Guoliang
Lu, Jing
Zhang, Jiahui
Feng, Lin
Wang, Bing
Yu, Hang
Xu, Yingjie
Lin, Jinzhong
摘要： Frequent outbreaks of coronavirus make the development of an effective vaccine imperative. Recently, vaccines based on in-vitro transcribed messenger RNA (mRNA) have shown great potential. The streamlined manufacturing of mRNA molecules, combined with the superior flexibility in the antigen screening, greatly accelerates the development process. When using an mRNA platform to develop a vaccine, initial antigen choice plays a crucial role in determining the final efficacy and safety of the vaccine. Furthermore, mRNA sequences that encode antigens require extensive optimization to ensure highly efficient and sustained expression. Our ongoing efforts to develop an effective mRNA vaccine against 2019-nCoV place emphasis on the virus-like particles (VLPs) as the presenting antigen. At the same time, our second fast track uses mRNA to express the receptor-binding domain of the spike protein(S-RBD). After extensive optimization, an mRNA cocktail containing three genes is able to produce 2019-nCoV virus-like particles highly similar to the native 2019-nCoV. Meanwhile, an mRNA vaccine candidate expressing S-RBD is being tested in mice for its immunogenicity. We will next compare both the efficacy and the safety of the two mRNA vaccines based on S-RBD and VLPs, respectively.
分类： 生物学 >> 生物医药 提交时间： 2017-05-10
Wang, Lan
Zhou, Guang-Biao
Liu, Ping
Song, Jun-Hong
Liang, Yang
Yan, Xiao-Jing
Xu, Fang
Wang, Bing-Shun
Mao, Jian-Hua
Shen, Zhi-Xiang
摘要： To enhance therapeutic efficacy and reduce adverse effects, practitioners of traditional Chinese medicine (TCM) prescribe a combination of plant species/minerals, called formulae, based on clinical experience. Nearly 100,000 formulae have been recorded, but the working mechanisms of most remain unknown. In trying to address the possible beneficial effects of formulae with current biomedical approaches, we use Realgar-Indigo naturalis formula (RIF), which has been proven to be very effective in treating human acute promyelocytic leukemia (APL) as a model. The main components of RIF are realgar, Indigo naturalis, and Salvia miltiorrhiza, with tetraarsenic tetrasulfide (A), indirubin (I), and tanshinone IIA (T) as major active ingredients, respectively. Here, we report that the ATI combination yields synergy in the treatment of a murine APL model in vivo and in the induction of APL cell differentiation in vitro. ATI causes intensified ubiquitination/degradation of promyelocytic leukemia (PML)-retinoic acid receptor #1; (RAR#1;) oncoprotein, stronger reprogramming of myeloid differentiation regulators, and enhanced G1/G0 arrest in APL cells through hitting multiple targets compared with the effects of mono- or biagents. Furthermore, ATI intensifies the expression of Aquaglyceroporin 9 and facilitates the transportation of A into APL cells, which in turn enhances A-mediated PML-RAR#1; degradation and therapeutic efficacy. Our data also indicate A as the principal component of the formula, whereas T and I serve as adjuvant ingredients. We therefore suggest that dissecting the mode of action of clinically effective formulae at the molecular, cellular, and organism levels may be a good strategy in exploring the value of traditional medicine.
提交时间： 2017-05-02
Li, HY [Li, Hu-Yan][ 1,2 ]
Li, H [Li, He][ 2 ]
Wang, BJ [Wang, Bing-Jie][ 2 ]
Gu, Q [Gu, Qun][ 3 ]
Jiang, ZQ [Jiang, Zhi-Qiang][ 3 ]
Wu, XD [Wu, Xue-Dong][ 2 ]
摘要： Poly[3-hydroxybutyrate-co-3-hydroxyvalerate] [PHBV]/chitin nanocrystals [CNC] composite scaffolds were synthesized by the salt leaching and thermally induced phase separation [TIPS] technique. The scaffolds have porous structures with macro-pores [100-300
提交时间： 2017-05-02
Huang, W [Huang, Wei][ 1,4 ]
Luo, XZ [Luo, Xian-Zi][ 1 ]
Wang, BJ [Wang, Bing-Jie][ 1 ]
Wei, WF [Wei, Wen-Feng][ 1 ]
Chen, P [Chen, Peng][ 1 ]
Gu, Q [Gu, Qun][ 1 ]
de Vos, S [de Vos, Sicco][ 2 ]
Wang, RY [Wang, Ru-Yin][ 3 ]
Joziasse, CAP [Joziasse, Cornelis A. P.][ 2 ]
摘要： Nanostructures of stereocomplex polylactide [sc-PLA] are obtained and studied in poly[l-lactide] [PLLA] doped with a low amount of poly[d-lactide] [PDLA] during successive melt-quenching, extrusion, spinning, and drawing processes corresponding to quiesce
点击量
通过
点击量
下载量
评论
待评议
