A Golden2-like transcription factor, BnGLK1a, improves chloroplast development, photosynthesis, and seed weight in rapeseed

Enhancing photosynthetic efficiency is a major goal for improving crop yields under agricultural field conditions and is associated with chloroplast biosynthesis and development.In this study,we demonstrate that Golden2-like 1a(BnGLK1a)plays an important role in regulating chloroplast development and photosynthetic efficiency.Overexpressing BnGLK1a resulted in significant increases in chlorophyll content,the number of thylakoid membrane layers and photosynthetic efficiency in Brassica napus,while knocking down BnGLK1a transcript levels through RNA interference(RNAi)had the opposite effects.A yeast two-hybrid screen revealed that BnGLK1a interacts with the abscisic acid receptor PYRABACTIN RESISTANCE 1-LIKE 1-2(BnPYL1-2)and CONSTITUTIVE PHOTOMORPHOGENIC 9 SIGNALOSOME 5A subunit(BnCSN5A),which play essential roles in regulating chloroplast development and photosynthesis.Consistent with this,BnGLK1a-RNAi lines of B.napus display hypersensitivity to the abscisic acid(ABA)response.Importantly,overexpression of BnGLK1a resulted in a 10%increase in thousand-seed weight,whereas seeds from BnGLK1a-RNAi lines were 16%lighter than wild type.We propose that BnGLK1a could be a potential target in breeding for improving rapeseed productivity.Our results not only provide insights into the mechanisms of BnGLK1a function,but also offer a potential approach for improving the productivity of Brassica species.

离子交换树脂在造纸废水脱盐中的应用研究

本研究采用732氢型阳离子交换树脂(以下简称阳离子树脂)、201×7氢氧型阴离子交换树脂(以下简称阴离子树脂)对造纸废水进行脱盐处理,研究了树脂在静态吸附和动态吸附过程中对造纸废水中离子的吸附性能。结果表明,阳离子树脂对造纸废水中Na^(+)、Ca2^(+)、Mg2^(+)和Fe3^(+)均有明显的去除效果,阴离子树脂对Cl^(-)和SO_(4)^(2-)有明显的去除效果。吸附时间为15 min、阳离子树脂∶阴离子树脂=1.2∶1.4(质量比),阳、阴离子树脂联用脱盐效果最佳。动态吸附过程中,随着流速增大,阳、阴离子树脂对离子的去除效果逐渐减弱,阳离子树脂适宜动态吸附流速为4~12 BV/h,阴离子树脂适宜动态吸附流速为4~10 BV/h。阳离子树脂的最佳再生条件为动态吸附流速4 BV/h、质量分数4%、体积3 BV,阳离子树脂再生率为94%;阴离子树脂的最佳再生条件为动态吸附流速4 BV/h、质量分数5%、体积3 BV、阴离子树脂再生率为84%。饱和吸附后树脂多次充分再生情况下,阳离子树脂再生率保持在90%以上,阴离子树脂再生率保持在80%以上。

基于像素化芯片的质子透射成像模拟研究

利用高能质子对病灶区域进行成像,直接获得病灶区域对质子的阻止能力,对于减小质子治疗中射程不确定度具有重要意义。作为质子CT的基本功能,透射成像对于辅助摆位具有重要意义。本研究在Geant4程序中设计并构建基于有源阵像素CMOS芯片的紧凑型质子CT探测器,并利用180 MeV质子对该系统的透射成像能力进行评估。通过径迹角度进行精确重建,对CTP404、CTP528以及自定义材料的CTP515模块进行模拟,获得空间、密度分辨力,以及质子相对阻止能力RSP的模拟结果。结果显示选用2°质子偏转角截断值时图像信噪比得到提升,使用CTP528模块测算的空间分辨力为3~4 lp/cm;使用CTP404模块测算密度分辨力优于0.05 g/cm^(3),RSP分辨力在5%以内;通过对选定材料的CTP515模块进行成像,表明该系统具备用于人体常见组织成像的潜力。

铁氮共掺杂生物炭催化过硫酸盐非均相深度处理造纸废水

本研究以麦草秸秆为原料,通过水合热解法制备铁氮共掺杂生物炭(Fe-NBC),将其作为催化剂应用于过硫酸盐非均相高级氧化反应体系,处理造纸废水二沉池出水。结果表明,Fe-NBC表面孔隙丰富,在热解过程中生成石墨C、Fe、Fe-N和Fe-C;同时生成吡啶N、石墨N和吡咯N等,能够高效催化过硫酸盐产生氧化自由基,有效降低废水生化出水的COD浓度。在过硫酸盐用量4 mmol/L及FeNBC用量0.4 g/L、催化降解120 min时,COD_(Cr)从(123±1) mg/L降至(58±1) mg/L,去除率为52%。FeNBC经4次处理回用后,催化活性变化不大,仍保持对COD较高的去除率。

不同造纸助剂对再生纸浆强度性能影响的研究

选用造纸工业常用的三种助剂阳离子淀粉、阳离子聚丙烯酰胺、漆酶/谷氨酸体系对再生纸浆进行处理,对其增强效果进行对比研究,处理的再生浆包括国产OCC浆和美废12#浆。实验结果表明,漆酶/谷氨酸体系对两种再生浆的强度性能提高效果最优,阳离子淀粉次之,阳离子聚丙烯酰胺最低。使用漆酶/谷氨酸体系处理时,国产OCC浆最佳的处理工艺条件为:漆酶1.0%、谷氨酸1.5%、温度50℃、反应时间90 min,抗张、撕裂、环压、耐破指数分别提高53.8%、38.6%、53.2%、50.0%;美废12#浆的处理工艺条件为:漆酶0.1%、谷氨酸0.2%、温度50℃、反应时间60 min,抗张、撕裂、环压、耐破指数分别提高33.1%、24.6%、17.6%、26.5%。

Groundwater flow through fractured rocks and seepage control in geotechnical engineering: Theories and practices

Groundwater flow through fractured rocks has been recognized as an important issue in many geotechnical engineering practices.Several key aspects of fundamental mechanisms,numerical modeling and engineering applications of flow in fractured rocks are discussed.First,the microscopic mechanisms of fluid flow in fractured rocks,especially under the complex conditions of non-Darcian flow,multiphase flow,rock dissolution,and particle transport,have been revealed through a com-bined effort of visualized experiments and theoretical analysis.Then,laboratory and field methods of characterizing hydraulic properties(e.g.intrinsic permeability,inertial permeability,and unsaturated flow parameters)of fractured rocks in different flow regimes have been proposed.Subsequently,high-performance numerical simulation approaches for large-scale modeling of groundwater flow in frac-tured rocks and aquifers have been developed.Numerical procedures for optimization design of seepage control systems in various settings have also been proposed.Mechanisms of coupled hydro-mechanical processes and control of flow-induced deformation have been discussed.Finally,three case studies are presented to illustrate the applications of the improved theoretical understanding,characterization methods,modeling approaches,and seepage and deformation control strategies to geotechnical engi-neering projects.

BnbHLH92a negatively regulates anthocyanin and proanthocyanidin biosynthesis in Brassica napus

Yellow seed trait is a desirable characteristic with potential for increasing seed quality and commercial value in rapeseed,and anthocyanin and proanthocyanidins(PAs)are major seed-coat pigments.Few transcription factors involved in the regulation of anthocyanin and PAs biosynthesis have been characterized in rapeseed.In this study,we identified a transcription factor gene BnbHLH92a(BnaA06T0441000ZS)in rapeseed.Overexpressing BnbHLH92a both in Arabidopsis and in rapeseed reduced levels of anthocyanin and PAs.Correspondingly,the expression profiles of anthocyanin and PA biosynthesis genes(TT3,BAN,TT8,TT18,and TTG1)were shown by quantitative real-time PCR to be inhibited in BnbHLH92a-overexpressing Arabidopsis seeds,indicating that BnbHLH92a represses the anthocyanin and PA biosynthesis pathway in Arabidopsis.BnbHLH92a physically interacts with the BnTTG1 protein and represses the biosynthesis of anthocyanins and PAs in rapeseed.BnbHLH92a also binds directly to the BnTT18 promoter and represses its expression.These results suggest that BnbHLH92a is a novel upstream regulator of flavonoid biosynthesis in B.napus.

紫外-可见分光光度法测定含铜废水中的铜离子

设计了一个通过紫外-可见分光光度法检测含铜废水中铜离子含量的本科教学实验。该实验基于芬顿反应原理,检测液中铜离子的存在可催化过氧化氢分解产生羟基自由基,后者将溶液中无色的3,3’,5,5’-四甲基联苯胺(TMB)氧化为黄色的TMB^(2+),利用TMB^(2+)在452 nm处的吸光度,即可实现对含铜废水中铜离子的定量分析。本实验操作简便、测定时间短、稳定性较好且安全环保,符合本科教学实验的基本要求。

电感耦合等离子体原子发射光谱法用于不锈钢保温杯浸出液中金属离子的测定

设计了一个利用电感耦合等离子体原子发射光谱法(ICP-AES)测定保温杯浸出液中金属离子的本科生仪器分析实验。以保温杯浸出液为检测对象,能极大激发学生实验兴趣,引导学生学以致用并进行深入探究,提高实验操作能力,培养团队协作精神。本实验内容及流程完整,实验试剂及过程安全绿色,实验样品处理快速简便,实验用时合理,适合本科实验教学。

A new classification of seepage control mechanisms in geotechnical engineering

Seepage flow through soils,rocks and geotechnical structures has a great influence on their stabilities and performances,and seepage control is a critical technological issue in engineering practices.The physical mechanisms associated with various engineering measures for seepage control are investigated from a new perspective within the framework of continuum mechanics;and an equation-based classification of seepage control mechanisms is proposed according to their roles in the mathematical models for seepage flow,including control mechanisms by coupled processes,initial states,boundary conditions and hydraulic properties.The effects of each mechanism on seepage control are illustrated with examples in hydroelectric engineering and radioactive waste disposal,and hence the reasonability of classification is demonstrated.Advice on performance assessment and optimization design of the seepage control systems in geotechnical engineering is provided,and the suggested procedure would serve as a useful guidance for cost-effective control of seepage flow in various engineering practices.

Modeling unsaturated flow in fractured rocks with scaling relationships between hydraulic parameters

Modeling unsaturated flow in fractured rocks is essential in various subsurface engineering applications,but it remains a great challenge due to the difficulties in determining the unsaturated hydraulic properties of rocks that contain various scales of fractures.It is generally accepted that the van Genuchten(VG)model can be applied to fractured rocks,provided that the hydraulic parameters could be representatively determined.In this study,scaling relationships between the VG parameters(a and n)and hydraulic conductivity(K)across 8 orders of magnitude,from 10^(-10)m/s to 10^(-2)m/s,were proposed by statistical analysis of data obtained from 1416 soil samples.The correlations were then generalized to predict the upper bounds of VG parameters for fractured rocks from the K data that could be obtained more easily under field conditions,and were validated against a limited set of data from cores,fractures and fractured rocks available in the literature.The upper bound estimates significantly narrow the ranges of VG parameters,and the representative values of a and n for fractured rocks at the field scale can then be determined with confidence by inverse modeling using groundwater observations in saturated zones.The proposed methodology was applied to saturated-unsaturated flow modeling in the right-bank slope at the Baihetan dam site with a continuum approach,showing that most of the flow behaviors in fractured rocks in this complex hydrogeological condition could be properly reproduced.The proposed method overcomes difficulties in suction measurement in fractured rocks with strong heterogeneity,and provides a feasible way for modeling of saturated-unsaturated flow in fractured rocks with acceptable engineering accuracy.

Variation in hydraulic conductivity of fractured rocks at a dam foundation during operation

Characterizing the permeability variation in fractured rocks is important in various subsurface applications,but how the permeability evolves in the foundation rocks of high dams during operation remains poorly understood.This permeability change is commonly evidenced by a continuous decrease in the amount of discharge(especially for dams on sediment-laden rivers),and can be attributed to fracture clogging and/or hydromechanical coupling.In this study,the permeability evolution of fractured rocks at a high arch dam foundation during operationwas evaluated by inverse modeling based on the field timeseries data of both pore pressure and discharge.A procedure combining orthogonal design,transient flow modeling,artificial neural network,and genetic algorithm was adopted to efficiently estimate the hydraulic conductivity values in each annual cycle after initial reservoir filling.The inverse results show that the permeability of the dam foundation rocks follows an exponential decay annually during operation(i.e.K/K0=0.97e^(-0.59t)+0.03),with good agreement between field observations and numerical simulations.The significance of the obtained permeability decay function was manifested by an assessment of the long-term seepage control performance and groundwater flow behaviors at the dam site.The proposed formula is also of merit for characterizing the permeability change in riverbed rocks induced by sediment transport and deposition.

基于统计工作的高校档案管理流程研究

高校档案馆藏数量和布局随时变化,如何及时、准确掌握档案馆藏,以指导档案实践工作是值得档案工作者思考的问题。本文以档案统计工作为出发点,结合高校档案工作特征,梳理高校档案管理流程,提出了基于《档案归档流水登记表》《档案分类统计表》《档案年度部门统计台账》的一套动态的高校档案管理流程,在一定程度上解决了档案馆藏难以掌握的难题,从而提高了档案工作效率。

基于微流控的生物被膜研究进展及口腔微生态系统应用展望

口腔是人体最重要的微生物储藏库之一,这些微生物通常以生物被膜的形式稳定地黏附于口腔内粘膜及牙齿表面,在病理条件下则可以深入髓腔及牙槽骨内,成为龋病、根尖周炎、牙周病等常见口腔疾病的主要病因,甚至与许多全身性疾病密切相关。在人类口腔微生态系统中,微生物种类繁多,生物被膜的构成及相互作用关系复杂,目前对其认识还十分有限;此外,在宿主免疫、口腔内外多种理化因素的调控下,生物被膜还可以出现不同的表型及生物特性,因此对其致病机制的研究也具有挑战性。微流控技术作为一种能够灵活操控微尺度流体的技术,不仅能够精准模拟理化微环境,还能够进行高通量可视化的分析,在生命分析化学及生物被膜的研究方面已经展现出显著优势,在口腔微生态系统研究中具有广阔的应用前景。本文将回顾近期微流控技术在生物被膜方面的研究进展,并结合口腔微生态系统中生物被膜研究的关键问题对微流控技术的应用做系统阐述和展望。

The kinase p38αfunctions in dendritic cells to regulate Th2-cell differentiation and allergic inflammation

Dendritic cells(DCs)play a critical role in controlling T helper 2(Th2)cell-dependent diseases,but the signaling mechanism that triggers this function is not fully understood.We showed that p38αactivity in DCs was decreased upon HDM stimulation and dynamically regulated by both extrinsic signals and Th2-instructive cytokines.p38α-specific deletion in cDC1s but not in cDC2s or macrophages promoted Th2 responses under HDM stimulation.Further study showed that p38αin cDC1s regulated Th2-cell differentiation by modulating the MK2−c-FOS−IL-12 axis.Importantly,crosstalk between p38α-dependent DCs and Th2 cells occurred during the sensitization phase,not the effector phase,and was conserved between mice and humans.Our results identify p38αsignaling as a central pathway in DCs that integrates allergic and parasitic instructive signals with Th2-instructive cytokines from the microenvironment to regulate Th2-cell differentiation and function,and this finding may offer a novel strategy for the treatment of allergic diseases and parasitic infection.