变压吸附实验装置的小型化、低成本化改进

目前的变压吸附实验中通常使用商品化设备,存在尺寸大、成本高、气路复杂等问题,不利于大规模开展本科实验教学。本文对变压吸附装置进行了小型化、低成本化改进,学生可以使用实验室常见材料自行搭建变压吸附装置,了解并掌握设备搭建、调试、运行的整个流程。以Li交换分子筛作为吸附剂,该设备的制氧效果与商用制氧机相当,出口氧气浓度可达95.8%。该装置具有安全性高、可反复拆装的特点,搭建、调试过程具有一定趣味性,适合用于应用化学、化学工程等本科专业的变压吸附实验教学,有利于激发学生对创制实验装置的兴趣,锻炼学生的动手能力,提高学生理论结合实际解决问题的能力。

Attenuation of the Activation of NLRP3 Inflammasome in Fibroblast Like Synoviocytes of Rheumatoid Arthritis by Baicalin through Regulating the Let-7i-3p/PI3K/Akt/NF-κB Signaling Axis

[Objectives]To study the effect and mechanism of baicalin on the activation of NLRP3 inflammasome in human fibroblast like synoviocytes of rheumatoid arthritis(HFLS-RA).[Methods]To confirm that baicalin alleviated the activation of NLRP3 inflammasome in HFLS-RA,the expression of NLRP3 before and after baicalin treatment was observed by immunofluorescence.Western blot was used to detect the protein expression of p-PI3K,p-Akt,NF-κB p65,NLRP3,ASC and caspase-1 after baicalin treatment for 48 h,and the contents of IL-1 and IL-18 in the supernatents were detected by ELISA.In order to explore the mechanism of baicalin alleviating the activation of NLRP3 inflammasome,the corresponding relationship between let-7i-3p and PIK3CA was verified by double luciferin and Westen blot analysis.The expression of let-7i-3p and PI3K before and after baicalin intervention was detected by RT-qPCR.let-7i-3p interference was used to verify whether baicalin mitigated the activation of enhanced NLRP3 inflammasome.[Results]Baicalin(50 and 100 mg/L)significantly reduced the activation of NLRP3 inflammasome,inhibited the protein expressions of p-PI3K,p-Akt,NF-κB p65,NLRP3,ASC and caspase-1,and the secretion of IL-1 and IL-18.let-7i-3p and PIK3CA had a targeted correspondence,and baicalin up-regulated the expression of let-7i-3p and down-regulated the expression of PIK3CA.Baicalin attenuated the activation of NLRP3 inflammasome enhanced by let-7i-3p interference.[Conclusions]Baicalin can up-regulate let-7i-3p expression,inhibit PI3K/Akt/NF-κB signal transduction,and thus reduce the activation of NLRP3 inflammasome in HFLS-RA.

原位法制备聚乙二醇/聚(丙烯酰胺-co-丙烯酸)荧光水凝胶

在丙烯酰胺和丙烯酸共聚交联网络中掺入线型聚乙二醇(PEG)形成半互穿聚合物网络结构以提高水凝胶的力学性能,同时引入柠檬酸(CA)和乙二胺(EDA)原位反应形成非共轭型荧光聚合物点(NCPD),一步制备了具有高回弹性的聚乙二醇/聚(丙烯酰胺-co-丙烯酸)PEG/P(AM-co-AA)荧光水凝胶。该水凝胶具有良好的力学强度、韧性,高荧光强度和荧光均一性,且光致发光具有金属离子敏感性。拉伸测试结果表明,PEG/P(AM-co-AA)荧光水凝胶的断裂强度达到~192.2 kPa,拉伸4倍后仍可以恢复到初始状态。光致发光研究结果表明,水凝胶在365 nm的波长激发下,可以发出明亮的蓝色荧光(发射波长434~467 nm)。荧光性能具有强Fe敏感性,猝灭效率可达99%。该荧光水凝胶在柔性电子器件和生物传感等领域具有潜在应用。

原位法制备石墨相碳/TiO2复合光催化剂及其高效降解新兴酚类污染物性能

绿色光催化技术在可持续水处理和环境修复领域具有广阔的应用前景.光催化效率在很大程度上取决于光催化剂,其中二氧化钛(Ti O2)因具有超强的光氧化能力、化学稳定性和低成本等优点而广泛应用于光催化降解水中各类有机污染物.然而,Ti O2的光催化效率仍然受限于其自身比表面积小、太阳光利用率低以及光生载流子复合速率快等缺点.为了克服以上缺点,进一步提高Ti O2的光催化效率,本研究采用简单易行的原位共缩合结合水热处理技术,以葡萄糖为碳源,四异丙氧基钛(TTIP)为钛源,成功制备了一系列由锐钛矿相Ti O2与石墨相碳组成的Ti O2/C复合光催化剂,它们在水中新兴酚类污染物的降解中表现出了优异的可见光光催化活性.通过X射线衍射、热重分析、X射线光电子能谱、孔隙率分析、扫描电镜、透射电镜、紫外-可见漫反射光谱等表征手段对催化剂的组成和结构、形貌、孔隙率性质及光吸收特性进行了表征.结果显示,Ti O2/C复合光催化剂具有独特的微孔/介孔结构,以及比Ti O2更大的比表面积(222-263 m^2 g^-1)和更窄的带隙能(2.50-2.77 e V).通过水中新兴酚类污染物如乙酰氨基酚(APAP)和对羟基苯甲酸甲酯(MPB)的可见光光催化降解实验研究了Ti O2/C的光催化性能.结果显示,Ti O2/C复合光催化剂表现出优于纯Ti O2和商用P25-Ti O2的可见光光催化活性.其中,性能最佳的Ti O2/C-10.3(碳掺杂量为10.3%)在可见光照射下20 min即可完全降解APAP,180 min可降解90%以上的MPB;Ti O2/C-10.3光催化降解APAP和MPB的表观速率常数分别是纯Ti O2的7.6和2.8倍,是商用P25-Ti O2的6.2和2.6倍.Ti O2/C复合光催化剂表现出良好的稳定性,能够在完成五次光催化循环实验后仍然保持其良好的光催化活性.通过光电化学实验、间接化学探针测试和电子自旋共振光谱分析并结合表征结果,揭示了Ti O2/C可见光光催化活性提高的原因.首先,石墨相碳的掺入降低了材料的带隙能,拓宽了材料的可见光吸收范围,同时石墨相碳可作为电子阱促进光生电子从Ti O2的价带转移到自身,从而有效抑制光生载流子的复合;其次,在复合催化剂中,锐钛矿相Ti O2与石墨相碳密切接触有利于光生载流子的有效分离,也可起到抑制光生载流子复合的作用;最后,复合催化剂较大的比表面积和独特的微孔/介孔双孔结构为APAP和MPB降解反应提供了充足活性位点,同时入射光在孔道内多次反射又进一步提高了催化剂对光能的利用率.在Ti O2/C光催化降解体系中检测到的主要活性物种有羟基自由基、光生空穴和超氧自由基,三者共同参与APAP和MPB的降解和矿化过程.通过对光催化降解中间产物的分析,分别提出了Ti O2/C复合光催化剂可见光催化降解APAP和MPB的路径.本研究为设计高效降解水中有机污染物的碳掺杂Ti O2光催化材料提供了新思路.

洞庭湖典型垸内沟渠沉积物不同形态氮的赋存特征

随着人类活动影响的加剧，洞庭湖局部区域已经出现轻中度富营养化，为了探究影响洞庭湖富营养化的因素，采用连续分级提取法针对洞庭湖垸内沟渠开展沉积物不同形态氮的赋存特征研究。结果表明研究区域沉积物总氮（TN）含量在586.82—1438．35mg·kg^-1之间，各形态氮的含量大小依次为：酸解态氮（HN）〉残渣态氮（RN）〉可交换态氮（EN）〉游离态氮（FN），分别占沉积物总氮的69．27％、16．72％、13．32％、0．69％。可矿化程度较高的HN占比最高，总可矿化有机氮平均277．15mg／kg，沉积物向上覆水中释放氮的能力较高，存在加剧洞庭湖区水体富营养化程度的风险，本研究可为洞庭湖沟渠水体富营养化控制和治理提供一定的理论依据。

Favorable haplotypes and associated genes for flowering time and photoperiod sensitivity identified by comparative selective signature analysis and GWAS in temperate and tropical maize

On the basis of growing environment,maize can largely be classified into temperate and tropical groups,leaving extensive genetic variation and evolutionary signatures in the maize genome.To identify candidate genes governing flowering time and photoperiod sensitivity,selective signature analysis and SNP-and haplotype-based GWAS were performed using 39,350 high-quality SNP markers in temperate and tropical maize groups consisting of 410 inbred lines phenotyped in three representative experiments in different latitudes.Selective signature analysis revealed 106 selective-sweep regions containing 423 candidate genes involved mainly in biological regulation and biosynthesis pathways.Among these genes,25 overlapped with known genes governing flowering time and photoperiod sensitivity and 37 were also detected by GWAS for days to tassel,anthesis-silk interval,and photoperiod sensitivity measured by days to silking.Only two of the candidate genes governing flowering time overlapped selective signals.Most haplotype alleles within significant haplotype loci showed the same direction of effect on flowering time and photoperiod sensitivity.The inbred lines carrying GATT at HapL499(haplotype locus 499)on chromosome 1 had relatively short flowering times.Lines carrying CA at HapL4054 on chromosome 10,TA at HapL4055 on chromosome 10,and GTTGT at HapL978 on chromosome 2 were less sensitive to photoperiod than lines carrying other haplotype alleles.Haplotype loci associated with flowering time and photoperiod sensitivity explained respectively 17.5%–18.6%and 11.2%–15.5%of phenotypic variation.Candidate genes and favorable haplotypes identified in this study may support the more efficient utilization of maize germplasm groups.

Discovery of Two Families of VSb-Based Compounds with V-Kagome Lattice

We report the structure and physical properties of two newly discovered compounds AV_(8)Sb_(12)and AV_(6)Sb_(6)(A=Cs,Rb),which have C_(2)(space group:Cmmm)and C_(3)(space group:R3 m)symmetry,respectively.The basic Vkagome unit appears in both compounds,but stacking differently.AV_(2)Sb_(2) layer is sandwiched between two V_(3)Sb_(5)layers in AV_(8)Sb_(12),altering the V-kagome lattice and lowering the symmetry of kagome layer from hexagonal to orthorhombic.In AV_(6)Sb_(6),the building block is a more complex slab made up of two half-V_(3)Sb_(5)layers that are intercalated by Cs cations along the c-axis.Transport property measurements demonstrate that both compounds are nonmagnetic metals,with carrier concentrations at around 10^(21)cm^(-3).No superconductivity has been observed in CsV_(8)Sb_(12)above 0.3 K under in situ pressure up to 46 GPa.Compared to CSV_(3)Sb_(5),theoretical calculations and angle-resolved photoemission spectroscopy reveal a quasi-two-dimensional electronic structure in CsV_(8)Sb_(12)with C_(2)symmetry and no van Hove singularities near the Fermi level.Our findings will stimulate more research into V-based kagome quantum materials.

Machine Learning-Aided Data Analysis in Single-Protein Conductance Measurement with Electron Tunneling Probes

The electrical tunneling sensors have excellent potential in the next generation of single-molecule measurement and sequencing technologies due to their high sensitivity and spatial resolution capabilities.Electrical tunneling signals that have been measured at a high sampling rate may provide detailed molecular information.Despite the extraordinarily large amount of data that has been gathered,it is still difficult to correlate signal transformations with molecular processes,which creates great obstacles for signal analysis.Machine learning is an effective tool for data analysis that is currently gaining more significance.It has demonstrated promising results when used to analyze data from single-molecule electrical measurements.In order to extract meaningful information from raw measurement data,we have combined intelligent machine learning with tunneling electrical signals.For the purpose of analyzing tunneling electrical signals,we investigated the clustering approach,which is a classic algorithm in machine learning.A clustering model was built that combines the advantages of hierarchical clustering and Gaussian mixture model clustering.Additionally,customized statistical algorithms were designed.It has been proven to efficiently gather molecular information and enhance the effectiveness of data analysis.

Generating a nanoscale blade-like optical field in a coupled nanofiber pair

An optical field with sub-nm confinement is essential for exploring atomic-or molecular-level light-matter interaction.While such fields demonstrated so far have typically point-like cross-sections,an optical field having a higher-dimensional cross-section may offer higher flexibility and/or efficiency in applications.Here,we propose generating a nanoscale blade-like optical field in a coupled nanofiber pair(CNP)with a 1-nm-width central slit.Based on a strong mode coupling-enabled slit waveguide mode,a sub-nm-thickness blade-like optical field can be generated with a cross-section down to~0.28 nm×38 nm at 1550 nm wavelength(i.e.,a thickness of~λ_(0)∕5000)and a peak-to-background intensity ratio(PBR)higher than 20 d B.The slit waveguide mode of the CNP can be launched from one of the two nanofibers that are connected to a standard optical fiber via an adiabatical fiber taper,in which a fundamental waveguide mode of the fiber can be converted into a high-purity slit mode with high efficiency(>98%)within a CNP length of less than 10μm at 1550 nm wavelength.The wavelengthdependent behaviors and group velocity dispersion in mode converting processes are also investigated,showing that such a CNP-based design is also suitable for broadband and ultrafast pulsed operation.Our results may open up new opportunities for studying light-matter interaction down to the sub-nm scale,as well as for exploring ultra-high-resolution optical technology ranging from super-resolution nanoscopy to chemical bond manipulation.

Generating a sub-nanometer-confined optical field in a nanoslit waveguiding mode

We propose to generate a sub-nanometer-confined optical field in a nanoslit waveguiding mode in a coupled nanowire pair(CNP).We show that,when a conventional waveguide mode with a proper polarization is evanescently coupled into a properly designed CNP with a central nanoslit,it can be efficiently channeled into a high-purity nanoslit mode within a waveguiding length<10μm.The CNP can be either freestanding or on-chip by using a tapered fiber or planar waveguide for input-coupling,with a coupling efficiency up to 95%.Within the slit region,the output diffraction-limited nanoslit mode offers an extremely confined optical field(∼0.3 nm×3.3 nm)with a peak-to-background ratio higher than 25 dB and can be operated within a 200-nm bandwidth.The group velocity dispersion of the nanoslit mode for ultrafast pulsed operation is also briefly investigated.Compared with the previous lasing configuration,the waveguiding scheme demonstrated here is not only simple and straightforward in structural design but is also much flexible and versatile in operation.Therefore,the waveguiding scheme we show here may offer an efficient and flexible platform for exploring light–matter interactions beyond the nanometer scale,and developing optical technologies ranging from superresolution nanoscopy and atom/molecule manipulation to ultra-sensitivity detection.

Development and accuracy of artificial intelligence-generated prediction of facial changes in orthodontic treatment:a scoping review

Artificial intelligence(AI)has been utilized in soft-tissue analysis and prediction in orthodontic treatment planning,although its reliability has not been systematically assessed.This scoping review was conducted to outline the development of AI in terms of predicting soft-tissue changes after orthodontic treatment,as well as to comprehensively evaluate its prediction accuracy.Six electronic databases(PubMed,EBSCOhost,Web of Science,Embase,Cochrane Library,and Scopus)were searched up to March 14,2023.Clinical studies investigating the performance of AI-based systems in predicting post-orthodontic soft-tissue alterations were included.The Quality Assessment of Diagnostic Accuracy Studies-2(QUADAS-2)and Joanna Briggs Institute(JBI)appraisal checklist for diagnostic test accuracy studies were applied to assess risk of bias,while the Grading of Recommendation,Assessment,Development,and Evaluation(GRADE)assessment was conducted to evaluate the certainty of outcomes.After screening 2500 studies,four non-randomized clinical trials were finally included for full-text evaluation.We found a low level of evidence indicating an estimated high overall accuracy of AI-generated prediction,whereas the lower lip and chin seemed to be the least predictable regions.Furthermore,the facial morphology simulated by AI via the fusion of multimodality images was considered to be reasonably true.Since all of the included studies that were not randomized clinical trials(non-RCTs)showed a moderate to high risk of bias,more well-designed clinical trials with sufficient sample size are needed in future work.

Hydrogen peroxide-activatable iodoBodipy-phthalhydrazid conjugate nanoparticles for cancer therapy

The dependence on outer light source strongly hinders clinical applications of photodynamic therapy(PDT)to the deep-seated tumor.However,the majority of documented PDT systems that function without the external light source rely on either the chemiluminescence resonance energy transfer(CRET)or fluorescence resonance energy transfer(FRET)mechanism,which decreases the energy transfer efficiency and reproducibility of PDT.Herein,we developed a novel single-molecule triplet photosensitizer(iodoBodipy(IBDP)-L)that can be chemiexcited to triplet excited state to generate reactive oxygen species instead of outer light irradiation.The direct bonding of phthalhydrazid moiety to iodoBodipy fluorophore evoked valid intramolecular energy transfer(IET),and once phthalhydrazid part is activated by hydrogen peroxide,the released reaction energy could excite the iodoBodipy-phthalhydrazid conjugate as a whole.Reaction product IBDP-L-COOH showed high triplet state quantum yield(ΦT=65%)and large spin-orbit coupling.A large amount of reactive oxygen species(ROS)was produced in MCF-7 cells,thus inhibiting the cell growth both in vitro and in vivo after IBDP-L was formulated into nanoparticles(NPs)via nanoprecipitation.We believe that the synthesized IodoBodipy-phthalhydrazid conjugate based on the IET mechanism will open a new door in the molecular design of efficient triplet photosensitizers for treating deeply seated tumors in the future.

Genome sequencing of Sitopsis species provides insights into their contribution to the B subgenome of bread wheat

Wheat(Triticum aestivum,BBAADD)is an allohexaploid species that originated from two polyploidization events.The progenitors of the A and D subgenomes have been identified as Triticum urartu and Aegilops tauschii,respectively.Current research suggests that Aegilops speltoides is the closest but not the direct ancestor of the B subgenome.However,whether Ae.speltoides has contributed genomically to the wheat B subgenome and which chromosome regions are conserved between Ae.speltoides and the B subgenome remain unclear.Here,we assembled a high-quality reference genome for Ae.speltoides,resequenced 53 accessions from seven species(Aegilops bicornis,Aegilops longissima,Aegilops searsii,Aegilops sharonensis,Ae.speltoides,Aegilops mutica[syn.Amblyopyrum muticum],and Triticumdicoccoides)and revealed their genomic contributions to the wheat B subgenome.Our results showed that centromeric regions were particularly conserved between Aegilops and Triticum and revealed 0.17 Gb of conserved blocks between Ae.speltoides and the B subgenome.We classified five groups of conserved and non-conserved genes between Aegilops and Triticum,revealing their biological characteristics,differentiation in gene expression patterns,and collinear relationships between Ae.speltoides and the wheat B subgenome.We also identified gene families that expanded in Ae.speltoides during its evolution and 789 genes specific to Ae.speltoides.These genes can serve as genetic resources for improvement of adaptability to biotic and abiotic stress.The newly constructed reference genome and large-scale resequencing data for Sitopsis species will provide a valuable genomic resource for wheat genetic improvement and genomic studies.

未来建筑师在小窝铺——从环境教育出发的乡村营造实践

小窝铺社区式环境教育中心项目由北京交通大学无止桥团队开展,试图为建筑师统筹的乡村振兴实践提供一个由高校学生主导的案例。该项目是一个由2017年延续至今的“陪伴式”乡建项目:项目以环境教育为出发点,以“建筑作为社会过程”为核心理念,通过小规模的物质空间建设结合一系列非物质性措施,推动首都水源地村落自然环境的保护和人居环境的改善,重塑人、自然、村落的关系;同时,为高校学生提供实践平台,推动乡村发展人才队伍的建设,为乡村振兴培养“未来建筑师”。

INTERFERENCE BY NON-HOST PLANT ROOTS AND ROOT EXUDATES IN THE INFECTION PROCESSES OF PHYTOPHTHORA NICOTIANAE

Crop rotations are widely used because they can significantly reduce the incidence of pests and diseases.The interactions between non-host roots and pathogens may be key in the inhibition of soilborne pathogens in crop rotations.Interactions between fennel(Foeniculum vulgare)roots/root exudates and Phytophthora nicotianae were investigated because of the known allelopathy between fennel and tobacco(Nicotiana tabacum).The effects of the key compounds in the fennel rhizosphere on the mycelial growth and zoospore behavior of P.nicotianae were assessed.The roots of fennel attracted P.nicotianae zoospores and inhibited their motility and the germination of cystospores,with some cystospores rupturing.4-ethylacetophenone,vanillin and N-formylpiperidine were consistently identified in the fennel rhizosphere and were found to interfere with the infection of P.nicotianae,especially vanillin.Hyphae treated with these compounds produced more abnormal branches and accumulated reactive oxygen species.These interspecific interactions between non-host roots and pathogens were found to be an important factor in the inhibition by fennel of infection by P.nicotianae.

Gut microbiota-derived metabolites contribute negatively to hindgut barrier function development at the early weaning goat model

Early weaning induces intestinal injury,leading to a series of long-term symptoms such as inflammation,malabsorption and diarrhea.In this study,we hypothesized that microbes and theirmetabolitesmodulate the host's inflammatory response to early weaning stress in a goatmodel.A total of 18 female Tibetan goat kids(n?9)wereweaned fromtheirmothers at 28 d(D28)and 60 d(D60)postpartum.D60 and D28 groupswere fed the same solid diet ad libitum fromweaning to 75 d of age.The colonic epithelium was subject to RNAsequencing,the caecal digesta metabolomics were assessed by liquid chromatographyetandem mass spectrometry(LC-MS/MS),and the caecal microbiota composition was analysed by 16S ribosomal RNA gene sequencing.We foundthatearlyweaningsubstantially increased the colonic pro-apoptotic gene expressionof B-cell lymphoma associated X(Bax),caspase-9,and caspase-3,and decreased the expression of zonula occludens-1(ZO-1)and claudin-1(P<0.01).In addition,a significant Bacteroides acidifaciens enrichmentwas observed in the hindgut of early-weaned goats(P<0.01),which negatively correlated with lysophosphatidylcholine products.Similarly,the chemokine signaling,IL-17 signaling,and peroxisome proliferatorsactivated receptor(PPAR)signaling pathways were upregulated in the colonic mucosa of the early-weaned goats.By applying caecal microbiota transplantation from goats to defaunated C57/6J mice,we confirmed that caecalmicrobiota of D28 goat kids increased the relative abundance of B.acidifaciens and significantly upregulated the genes of Bax,G proteinecoupled receptor(GPR)109A,GPR 43,fatty acid binding protein 6,nuclear receptor subfamily 1 group H member 3,angiotensin converting enzyme 2,and IL-6 expression(P<0.05),and decreased ZO-1,and claudin-1 protein expression in the mice jejunum and colon(P<0.001).These results proposed that the hindgut microbiota andmetabolites mediate the barrier functionweakening duringearlyweaning,and the relative abundance of B.acidifacienswas negatively correlatedwiththe hindgut barrier gene expression.This studydemonstrateshowweaningstress canaffectkeyhostemicrobe interaction regulators in the hindgut,in a lysophosphatidylcholine dependent and independent manner.Furthermore,based on our mice data,these results are transferable to other mammal species.

Induced Dopaminergic Neurons for Parkinson's Disease Therapy: Targeting the Striatum or Midbrain/Substantia Nigra Pars Compacta?

Parkinson's disease(PD)is a common neurodegenerative disease among the elderly,characterized by the specific loss of dopaminergic(DAergic)neurons in the substantia nigra pars compacta(SNpc)and defects in dopamine(DA)release in the striatum.