Comparison of Skull Morphology in Two Species of Genus Liua(Amphibia:Urodela: Hynobiidae),L.shihi and L.tsinpaensis

Skull characteristics play an important role in the systematics of tailed salamanders, in this study, the skulls ofLiua shihi and L. tsinpaensis were compared using a clearing and double-staining technique. The results showed that in L. tsinpaensis, the vomerine tooth rows are in a ＂ ＂ shape, the length of the inner vomerine tooth series is nearly equal to that of the outer series, the vomerine tooth rows do not extend beyond the choanae, an ossified articular bone is absent, the basibranchial is rod shaped, the radial loops exhibit a figure-eight shape, the cornua has two cylindrical branches, the urohyal is rod shaped, and the end of the ceratohyal is not ossified; these features differ considerably from those of L. shihi. The ossification of the posterior portion of the ceratohyal and the present or absent of ossified articular might represent ecological adaptation to feeding in different environments.

Enhanced mechanical properties and degradation rate of Mg-Ni-Y alloy by introducing LPSO phase for degradable fracturing ball applications

In this work,as-cast Mg-Ni-Y alloys were proposed to develop a feasible material for fracturing balls,and their mechanical performance and corrosion behavior were systematically investigated.Long period stacking order(LPSO)phase was firstly introduced to improve both the mechanical properties and degradation rate of magnesium alloys.With the increase of LPSO phase,the compressive strength was improved significantly,while the elongation of the alloys decreased owing to the relatively brittle nature of LPSO phase.Due to the higher corrosion potential of LPSO phase,the LPSO phase can accelerate the corrosion process by providing more micro-couples.However,the LPSO phase would serve as the corrosion barrier between the corrosion medium and the matrix when the contents of LPSO phase are too high in Mg92.5Ni3Y4.5 and Mg87.5Ni5Y7.5 alloys.As-cast Mg97.5Ni1Y1.5 alloy with satisfactory mechanical properties and rapid degradation rate was successfully developed,exhibiting a high degradation rate of 6675 mm/a(93℃)in 3 wt.%KCl solution and a favorable ultimate compressive strength of 410 MPa.The degradation rate of Mg97.5Ni1Y1.5 alloy is 2-5 times of the current commercial magnesium alloy fracturing materials.

Tomato DCL2b is required for the biosynthesis of 22-nt small RNAs, the resulting secondary siRNAs, and the host defense against ToMV

The tomato encode four functional DCL families,of which DCL2 is poorly studied.Here,we generated loss-of-function mutants for a tomato DCL2 gene,dcl2b,and we identified its major role in defending against tomato mosaic virus in relation to both natural and manual infections.Genome-wide small RNA expression profiling revealed that DCL2b was required for the processing 22-nt small RNAs,including a few species of miRNAs.Interestingly,these DCL2b-dependent 22-nt miRNAs functioned similarly to the DCL1-produced 22-nt miRNAs in Arabidopsis and could serve as triggers to generate a class of secondary siRNAs.In particular,the majority of secondary siRNAs were derived from plant defense genes when the plants were challenged with viruses.We also examined differentially expressed genes in dcl2b through RNA-seq and observed that numerous genes were associated with mitochondrial metabolism and hormone signaling under virus-free conditions.Notably,when the loss-of-function dcl2b mutant was challenged with tomato mosaic virus,a group of defense response genes was activated,whereas the genes related to lipid metabolism were suppressed.Together,our findings provided new insights into the roles of tomato DCL2b in small RNA biogenesis and in antiviral defense.

Discovery of an Internasal Bone in Hynobius maoershanensis(Urodela:Hynobiidae)

Internasal bones have generally been recorded in teleostean and tetrapod fossils, being absent in most extant vertebrates. Presently, there has been one case of the internasal bone discovered in a living salamander, Pseudohynobius puxiongensis （Caudata： Hynobiidae）. The second case discovered in living salamanders is reported in this article, which is present in one of five specimens ofHynobius maoershanensis, a species endemic to China. This case is again regarded as individual variation. Thus, the presence of an ＂internasal bone＂ may represent intraspecific variation and is thus a misleading taxonomic character.

Sexual Dimorphism of the Jilin Clawed Salamander,Onychodactylus zhangyapingi,(Urodela:Hynobiidae:Onychodactylinae) from Jilin Province,China

Sexual dimorphism in size and shape is common in many organisms, and is a key evolutionary feature. In this study, we analyzed morphometric data of the Jilin clawed salamander Onychodactylus zhangyapingi, an endemic Chinese salamander, to examine sexual size and shape dimorphism. The morphometric data included 14 characteristics of 13 females and 11 males and was analyzed using univariate and multivariate methods. Our results showed that sexual dimorphism occurs not only in body size, but also in body shape. Males have a longer snout-vent length than females, a rarely reported pattern of male-biased sexual size dimorphism. Females have a larger space between the axilla and groin than males, while males have longer and larger tails compared to females. The sexual dimorphism in body size and shape can be explained by existing theories, but there is little data for the mating system, behavior, reproduction, or ecology of O. zhangyapingi, so further studies are required.

Morphology-dependent activation of hydrogen peroxide with Cu_(2)O for tetracycline hydrochloride degradation in bicarbonate aqueous solution

The design of efficient heterogeneous catalysts in bicarbonate-activated hydrogen peroxide systems(BAP)is a hot topic in wastewater treatment.In this work,Cu_(2)O nanoparticles with different morphologies including cubic shape(c-Cu_(2)O),octahedron shape(o-Cu_(2)O)and spherical shape(s-Cu_(2)O),were applied in BAP for the first time to degrade tetracycline hydrochloride(TC).Compared with Cu^(2+)ions and CuO,TC degradation was boosted in the presence of Cu_(2)O in the BAP system,with the degradation rate following the order c-Cu_(2)O>o-Cu_(2)O>s-Cu_(2)O.The morphology-dependent effects could be linearly correlated with the ratio of surface oxygen species(O_S),but not with the surface area or Cu(Ⅰ)ratio.The c-Cu_(2)O catalyst with exposure of(100)facets contained 76.6%O_Sas the active site for H_(2)O_(2)adsorption and activation,while the value was much lower for o-Cu_(2)O and s-Cu_(2)O with dominant(111)facets.The presence of HCO_(3)-enhanced the interactions among Cu_(2)O,H_(2)O_(2)and TC,leading to facile oxidation of Cu(Ⅰ)to Cu(Ⅱ)by H_(2)O_(2),and the formation of various reactive species such as hydroxyl radicals and Cu(Ⅲ)contributed to TC degradation.This work provides a new method for enhancing H_(2)O_(2)activation with heterogeneous catalysts by crystal facet engineering.

2-[3-氰基呋喃-2(5H)-亚基]丙二腈衍生物的合成及其对Pd^(2+)的识别

通过两步反应合成了一种2-(3-氰基呋喃-2(5H)-亚甲基)丙二腈衍生物TCF-Pyn,该化合物在MeCN/磷酸缓冲容溶液(PBS)(V∶V=2∶8,PBS 2×10^(-2) mol/L,pH=7.4)混合溶液中能高选择性荧光"OFF-ON"识别Pd^(2+),发射波长达到近红外区(653 nm).该探针具有较好的抗干扰能力、较宽的pH适用范围(3~8)和较低的检测限(6.92μmol/L).应用研究表明,TCF-Pyn能检测真实水样中的Pd^(2+),并可对活细胞中的Pd^(2+)进行荧光成像.

Effect of Ni on the microstructure, mechanical properties and corrosion behavior of MgGd_1Ni_(x) alloys for fracturing ball applications

The effects of Ni addition on the mechanical properties, corrosion behaviors, and corrosion mechanism of Mg Gd_1 Ni_(x) alloys have been investigated by compressive tests, weight loss, hydrogen evolution, and scanning electron microscopy. The results show that the constitution of the second phase is large dependence on Ni/Gd molar ratios, which can transform from LPSO(long-period stacking ordered)+Mg_5 Gd,LPSO to eutectic phase. In addition, with increasing Ni/Gd molar ratios, the content of second phase increases gradually, while the LPSO phase shows a parabola relationship. Furthermore, the formation of Nicontaining LPSO phase not only can improve the strength but also accelerate the degradation of Mg alloys owing to the galvanic corrosion. The optimal properties with ultimate compressive strength, degradation rate are 340 MPa, 2066 mm/y for Mg Gd1 Ni0.75, respectively, which can meet the engineering application standard of fracturing ball and can be used as candidate materials for fracturing ball.

在线同伴反馈情感识别与可视化:促进教师深度反思与教学问题改进

在线课例研究是由教师学习共同体围绕特定的专业发展目标,借助在线学习平台合作开展教学设计修改、教学实施、课堂观察、课后研讨与教学反思的专业发展实践活动。在课例研究活动中,教师获得了大量的同伴反馈文本数据。智能识别与可视化同伴反馈文本情感,有助于及时发现教师集体共识信息与关键教学问题。为此,本研究基于机器学习技术构建了在线同伴反馈文本情感识别与可视化模型,包括同伴反馈文本数据采集、基于BERT模型的文本情感识别、文本主题抽取和情感可视化报告自动生成。研究采用实验研究与案例研究法分析了应用效果,结果表明:反馈文本情感识别模型具有较高的准确率,支持快速发现教师集体共识信息,生成的同伴反馈情感可视化报告有助于教师进行深度反思和教学问题改进。

Bioinformatic analysis of microRNA biogenesis and function related proteins in eleven animal genomes

MicroRNAs are -22 nt long small non-coding RNAs that play important regulatory roles in eukaryotes. The biogenesis and functional processes of microRNAs require the participation of many proteins, of which, the well studied ones are Dicer, Drosha, Argonaute and Exportin 5. To systematically study these four protein families, we screened 11 animal genomes to search for genes encoding above mentioned proteins, and identified some new members for each family. Domain analysis results revealed that most proteins within the same family share identical or similar domains. Alternative spliced transcript variants were found for some proteins. We also examined the expression patterns of these proteins in different human tissues and identified other proteins that could potentially interact with these proteins. These findings provided systematic information on the four key proteins involved in microRNA biogenesis and functional pathways in animals, and will shed light on further functional studies of these proteins.

An ultrapotent RBD-targeted biparatopic nanobody neutralizes broad SARS-CoY-2 variants

The wide transmission and host adaptation of SARS-CoV-2 have led to the rapid accumulation of mutations,posing significant challenges to the effectiveness of vaccines and therapeutic antibodies.Although several neutralizing antibodies were authorized for emergency clinical use,convalescent patients derived natural antibodies are vulnerable to SARS-CoV-2 Spike mutation.

Potential coexistence of both bacterial and eukaryotic small RNA biogenesis and functional related protein homologs in Archaea

RNA silencing plays crucial roles in both bacteria and eukaryotes, yet its machinery appears to differ in these two kingdoms. A couple of Argonaute protein homologs have been reported in some archaeal species in recent years. As Argonaute protein is the key component of eukaryotic RNA silencing pathways, such findings suggested the possibility of existence of eukaryotic RNA silencing like pathways in Archaea, which present the life forms between prokaryotes and eukaryotes. To further explore such hypothesis, we systematically screened 71 fully sequenced archaeal genomes, and identified some proteins containing homologous regions to the functional domains of eukaryotic RNA silencing pathway key proteins. The phylogenetic relationships of these proteins were analyzed. The conserved functional amino acids between archaeal and eukaryotic Piwi domains suggested their fimctional similarity. Our results provide new clues to the evolution of RNA silencing pathways.

Durable pluripotency and haploidy in epiblast stem cells derived from haploid embryonic stem cells in vitro

Haploid pluripotent stem cells,such as haploid embryonic stem cells(haESCs),facilitate the genetic study of recessive traits.In vitro,fish haESCs maintain haploidy in both undifferentiated and differentiated states,but whether mammalian haESCs can preserve pluripotency in the haploid state has not been tested.Here,wereport thatmousehaESCs can differentiate in vitro into haploid epiblast stem cells(haEpiSCs),which maintain an intact haploid genome,unlimited self-renewal potential,and durable pluripotency to differentiate into various tissues in vitro and in vivo.Mechanistically,the maintenance of self-renewal potential depends on the Activin/bFGF pathway.We further show that haEpiSCs can differentiate in vitro into haploid progenitor-like cells.When injected into the cytoplasm of an oocyte,androgenetic haEpiSC(ahaEpiSCs)can support embryonic development until midgestation(E12.5).Together,these resultsdemonstrate durable pluripotency inmousehaESCs andhaEpiSCs,aswell asthe valuable potential of using these haploid pluripotent stem cells in high-throughput genetic screening.

Structural Insights into Substrate Selectivity, Catalytic Mechanism,and Redox Regulation of Rice Photosystem Ⅱ Core Phosphatase

Photosystem Ⅱ (PSII)core phosphatase (PBCP)selectively dephosphorylates PSII core proteins including D1,D2,CP43,and PsbH.PBCP function is required for efficient degradation of the D1 protein in the repair cycle of PSII,a supramolecular machinery highly susceptible to photodamage during oxygenic photosynthesis.Here we present structural and functional studies of PBCP from Oryza sativa (OsPBCP).In a symmetrical homodimer of OsPBCP,each monomer contains a PP2C-type phosphatase core domain,a large motif characteristic of PBCPs,and two Small motifs around the active site.The large motif contributes to the formation of a substrate-binding surface groove,and is crucial for the selectivity of PBCP toward PSII core proteins and against the light-harvesting proteins.Remarkably,the phosphatase activity of OsPBCP is strongly inhibited by glutathione and H202.S-Glutathionylation of cysteine residues may introduce steric hindrance and allosteric effects to the active site.Collectively,these results provide detailed mechanistic insights into the substrate selectivity,redox regulation,and catalytic mechanism of PBCP.

Evolutionary and Functional Analysis of the Key Pluripotency Factor Oct4 and Its Family Proteins

Oct4 is one of the key pluripotent factors essential for embryonic stem cells and induced pluripotent stem （iPS） cells. Oct4 belongs to the POU domain family, which contains multiples genes with various important functions. Although the function of Oct4 has been extensively studied, detailed comparison of Oct4 with other POU family genes and their evolutionary analysis are still lacking. Here, we systematically identified POU family genes from lower to higher animal species. We observed an expansion of POU family genes in vertebrates, with an additional increment in mammalian genomes. We analyzed the phylogenetic relationship, tissue specific expression profiles and regulatory networks of POU family genes of the human genome, and predicted the putative binding microRNAs of human POU family genes. These results provide the first comprehensive evolutionary and comparative analysis of POU family genes, which will help to better understand the relationships among POU family genes and shed light on their future functional studies.

Comprehensive evaluation of multiple cropping systems on upland red soil

According to the principles and methods of ecology and system engineering,we set up an evaluation indicator system for multi-component and multiple crop-ping systems,evaluated the comprehensive benefits of multi-component and multiple cropping systems using grey relation clustering analysis and screened out the optimized model based on research done in the upland red soil in Jiangxi Agricultural University from 1984 to 2004.The results show that the grey relation degree of"cabbage/potato/maize-sesame"was the highest among 23 multi-component and multiple cropping systems and was clustered into the optimized system.This indicates that"cabbage/potato/maize-sesame"can bring the best social,economic and ecological benefits,increase product yield and farmers’income and promote sustainable development of agricultural production.Therefore,it is suitable for promotion on upland red soil.The grey relation degree of"canola/Chinese milk vetch/maize/mung bean/maize"was second,which is suitable for imple-mentation at the city outskirts.In conclusion,these two planting patterns are expected to play important roles in the reconstruction of the planting structure and optimization of the planting patterns on upland red soil.