Understanding Molecular Structures of Buried Interfaces in Halide Perovskite Photovoltaic Devices Nondestructively with Sub‐Monolayer Sensitivity Using Sum Frequency Generation Vibrational Spectroscopy

As performance of halide perovskite devices progresses, the device structure becomes more complex with more layers. Molecular interfacial structures between different layers play an increasingly important role in determining the overall performance in a halide perovskite device. However, current understanding of such interfacial structures at a molecular level nondestructively is limited, partially due to a lack of appropriate analytical tools to probe buried interfacial molecular structures in situ. Here, sum frequency generation (SFG) vibrational spectroscopy, a state‐of‐the‐art nonlinear interface sensitive spectroscopy, is introduced to the halide perovskite research community and is presented as a powerful tool to understand molecule behavior at buried halide perovskite interfaces in situ. It is found that interfacial molecular orientations revealed by SFG can be directly correlated to halide perovskite device performance. Here how SFG can examine molecular structures (e.g., orientations) at the perovskite/hole transporting layer and perovskite/electron transporting layer interfaces is discussed. This will promote the use of SFG to investigate molecular structures of buried interfaces in various halide perovskite materials and devices in situ nondestructively with a sub‐monolayer interface sensitivity. Such research will help to elucidate structure–function relationships of buried interfaces, aiding in the rational design/development of halide perovskite materials/devices with improved performance.     

Economical production of isomaltulose from agricultural residues in a system with sucrose isomerase displayed on Bacillus subtilis spores

Bioprocess and Biosystems Engineering - A safe, efficient, environmentally friendly process for producing isomaltulose is needed. Here, the biocatalyst, sucrose isomerase (SIase) from Erwinia...     

Clinical Features and Treatment of 2019-nCov Pneumonia Patients in Wuhan: Report of A Couple Cases

正Dear Editor,Till January 20, 2020, the 2019-new coronavirus(2019-nCoV) has caused more than one hundred cases in Wuhan(WMHC 2020). During a retrospective study of recent pneumonia patients in our department, we found two patients who are likely being infected with the 2019-nCoV.     

Antibody response and therapy in COVID-19 patients: what can be learned for vaccine development?

Science China Life Sciences - The newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected millions of people and caused tremendous morbidity and mortality worldwide....     

Chromosome‐level genome assembly of an important pine defoliator,Dendrolimus punctatus (Lepidoptera; Lasiocampidae)

Dendrolimus spp. are important destructive pests of conifer forests, and Dendrolimus punctatus Walker (Lepidoptera; Lasiocampidae) is the most widely distributed Dendrolimus species. During periodic outbreaks, this species is said to make “fire without smoke” because large areas of pine forest can be quickly and heavily damaged. Yet, little is known about the molecular mechanisms that underlie the unique ecological characteristics of this forest insect. Here, we combined Pacific Biosciences (PacBio) RSII single‐molecule long reads and high‐throughput chromosome conformation capture (Hi‐C) genomics‐linked reads to produce a high‐quality, chromosome‐level reference genome for D. punctatus. The final assembly was 614 Mb with contig and scaffold N50 values of 1.39 and 22.15 Mb, respectively, and 96.96% of the contigs anchored onto 30 chromosomes. Based on the prediction, this genome contained 17,593 protein‐coding genes and 56.16% repetitive sequences. Phylogenetic analyses indicated that D. punctatus diverged from the common ancestor of Hyphantria cunea, Spodoptera litura and Thaumetopoea pityocampa ~ 108.91 million years ago. Many gene families that were expanded in the D. punctatus genome were significantly enriched for the xenobiotic biodegradation system, especially the cytochrome P450 gene family. This high‐quality, chromosome‐level reference genome will be a valuable resource for understanding mechanisms of D. punctatus outbreak and host resistance adaption. Because this is the first Lasiocampidae insect genome to be sequenced, it also will serve as a reference for further comparative genomics.     

UDP‐Api/UDP‐Xyl synthases affect plant development by controlling the content of UDP‐Api to regulate the RG‐II‐borate complex

Rhamnogalacturonan‐II (RG‐II) is structurally the most complex glycan in higher plants, containing 13 different sugars and 21 distinct glycosidic linkages. Two monomeric RG‐II molecules can form an RG‐II‐borate diester dimer through the two apiosyl (Api) residues of side chain A to regulate cross‐linking of pectin in the cell wall. But the relationship of Api biosynthesis and RG‐II dimer is still unclear. In this study we investigated the two homologous UDP‐D‐apiose/UDP‐D‐xylose synthases (AXSs) in Arabidopsis thaliana that synthesize UDP‐D‐apiose (UDP‐Api). Both AXSs are ubiquitously expressed, while AXS2 has higher overall expression than AXS1 in the tissues analyzed. The homozygous axs double mutant is lethal, while heterozygous axs1/+ axs2 and axs1 axs2/+ mutants display intermediate phenotypes. The axs1/+ axs2 mutant plants are unable to set seed and die. By contrast, the axs1 axs2/+ mutant plants exhibit loss of shoot and root apical dominance. UDP‐Api content in axs1 axs2/+ mutants is decreased by 83%. The cell wall of axs1 axs2/+ mutant plants is thicker and contains less RG‐II‐borate complex than wild‐type Col‐0 plants. Taken together, these results provide direct evidence of the importance of AXSs for UDP‐Api and RG‐II‐borate complex formation in plant growth and development.     

汉江中下游浮游植物群落结构及水质评价

南水北调中线工程调水后,汉江中下游水华频发引起社会关注。为掌握调水后汉江中下游浮游植物的群落结构特征,于2017年11月、2018年2月、4月和8月在汉江中下游的8个断面对浮游植物进行了定量调查。调查结果显示:共鉴定浮游植物163种,群落组成以硅藻门(Bacillariophyta)、绿藻门(Chlorophyta)为主,其次是蓝藻门(Cyanophyta)。浮游植物优势种主要为硅藻门的梅尼小环藻(Cyclotella meneghiniana)、颗粒直链藻最窄变种(Melosira granulata var.)、变异直链藻(Melosira varians)、颗粒直链藻(Melosira granulata),隐藻门的卵形隐藻(Cryptomonas ovata),蓝藻门的弯曲颤藻(Oscillatoria sp.)和伪鱼腥藻(Pseudoanabaena sp.),且都有较高的优势度。浮游植物密度和生物量的季节变化范围分别为0. 33×106cells/L～1. 82×106cells/L和0. 49 mg/L～7. 38 mg/L。基于Shannon-Weaver多样性指数和Pielou均匀度指数以及优势种评价法对汉江中下游的水质进行评价,判断汉江中下游水质整体处于中污状态。