Hybrid response surface method for system reliability analysis of pilereinforced slopes

To consider the complex soil-structure interaction in a pile-slope system,it is necessary to analyze the performance of pile-slope systems based on a three-dimensional(3D)numerical model.Reliability analysis of a pile-slope system based on 3D numerical modeling is very challenging because it is computationally expensive and the performance function of the pile failure mode is only defined in the safe domain of soil stability.In this paper,an efficient hybrid response surface method is suggested to study the system reliability of pile-reinforced slopes,where the support vector machine and the Kriging model are used to approximate performance functions of soil failure and pile failure,respectively.The versatility of the suggested method is illustrated in detail with an example.For the example examined in this paper,it is found that the pile failure can significantly contribute to system failure,and the reinforcement ratio can effectively reduce the probability of pile failure.There exists a critical reinforcement ratio beyond which the system failure probability is not sensitive to the reinforcement ratio.The pile spacing affects both the probabilities of soil failure and pile failure of the pile-reinforced slope.There exists an optimal location and an optimal length for the stabilizing piles.

Single-cell RNA sequencing of meiocytes and microspores reveals the involvement of the Rf4 gene in redox homeostasis of CMS-C maize

Normal microsporogenesis is determined by both nuclear and mitochondrial genes. In maize C-type cytoplasmic male sterility, it is unclear how the development of meiocytes and microspores is affected by the mitochondrial sterility gene and the nuclear restorer gene. In this study, we sequenced the transcriptomes of single meiocytes(tetrad stage) and early mononucleate microspores from sterile and restorer lines. The numbers of expressed genes varied in individual cells and fewer than half of the expressed genes were common to the same cell types. Four comparisons revealed 3379 differentially expressed genes(DEGs), with 277 putatively associated with mitochondria, 226 encoding transcription factors,and 467 possibly targeted by RF4. KEGG analysis indicated that the DEGs in the two lines at the tetrad stage were involved predominantly in carbon metabolism and in amino acid biosynthesis and metabolism, whereas the DEGs during the transition from the tetrad stage to the early mononucleate stage were associated mostly with regulation of protein metabolism, fatty acid metabolism, and anatomical structure morphogenesis. Thus, meiocyte and microspore development was affected by the surrounding cells and the restorer gene, and the restorer gene helped restore the redox homeostasis of microspores and the normal cellular reconstruction during the transition.

Use of DNA metabarcoding of bird pellets in understanding raptor diet on the Qinghai-Tibetan Plateau of China

Background:Diet analysis is essential to understanding the functional role of large bird species in food webs.Mor-phological analysis of regurgitated bird pellet contents is time intensive and may underestimate biodiversity.DNA metabarcoding has the ability to circumvent these issues,but has yet to be done.Methods:We present a pilot study using DNA metabarcoding of MT-RNR1 and MT-CO1 markers to determine the species of origin and prey of 45 pellets collected in Qinghai and Gansu Provinces,China.Results:We detected four raptor species[Eurasian Eagle Owl(Bubo bubo),Saker Falcon(Falco cherrug),Steppe Eagle(Aquila nipalensis),and Upland Buzzard(Buteo hemilasius)]and 11 unique prey species across 10 families and 4 classes.Mammals were the greatest detected prey class with Plateau Pika(Ochotona curzoniae)being the most frequent.Observed Shannon’s and Simpson’s diversity for Upland Buzzard were 1.089 and 0.479,respectively,while expected values were 1.312±0.266 and 0.485±0.086.For Eurasian Eagle Owl,observed values were 1.202 and 0.565,while expected values were 1.502±0.340 and 0.580±0.114.Interspecific dietary niche partitioning between the two spe-cies was not detected.Conclusions:Our results demonstrate successful use of DNA metabarcoding for understanding diet via a novel noninvasive sample type to identify common and uncommon species.More work is needed to understand how raptor diets vary locally,and the mechanisms that enable exploitation of similar dietary resources.This approach has wide ranging applicability to other birds of prey,and demonstrates the power of using DNA metabarcoding to study species noninvasively.

Synthesis and cytotoxic activity of 7-alkynyl camptothecin derivatives

Several 7-alkynyl camptothecin derivatives were prepared via Sonogashira coupling. And anti-tumor activities of these compounds were evaluated against human esophageal cancer cell line （Eca-109）, human chronic myeloid leukaemia cell line （K562）, bladder cancer cell line （5637） and gastric cell line （SGC7901）. Compounds 9a--d and 10a exhibited remarkable in vitro cytotoxic activity, compared with topotecan.

CPAL, as a New Mediator of Cardiomyocyte Metabolic Alterations and Pyroptosis, Regulates Myocardial Infarction Injury in Mice

Myocardial infarction (MI), the most serious of the ischemic heart diseases, is accompanied by myocardial metabolic disorders and the loss of cardiomyocytes. Increasing evidence has shown that long noncoding RNAs (lncRNAs) are involved in various pathological conditions such as cancer and cardiovascular diseases (CVDs), and are emerging as a novel biomarker for these disorders. This study aims to investigate the regulatory role and mechanisms of lncRNAs in myocardial remodeling in the setting of MI. We find that post-infarcted hearts exhibit a reduction of adenosine triphosphate (ATP) and an alteration of the glucose and lipid metabolism genes cluster of differentiation 36 (CD36), hexokinase 1 (HK1), and clucose transporter 4 (GLUT4), accompanied by cardiomyocyte pyroptosis. We then identify a previously unknown conserved lncRNA, AK009126 (cardiomyocyte pyroptosis-associated lncRNA, CPAL), which is remarkably upregulated in the myocardial border zone of MI mice. Importantly, the adeno-associated virus 9 (AAV9)-mediated silencing of endogenous CPAL by its short hairpin RNA (shRNA) partially abrogates myocardial metabolic alterations and cardiomyocyte pyroptosis during MI in mice. Mechanistically, CPAL is shown to bind directly to nuclear factor kappa B (NFκB) and to act as an activator of NFκB to induce NFκB phosphorylation in cardiomyocytes. We also find that CPAL upregulates caspase-1 expression at the transcriptional level and consequently promotes the release of interleukin (IL)-18 and IL-1β from cardiomyocytes. Collectively, our findings reveal the conserved lncRNA CPAL as a new regulator of cardiac metabolic abnormalities and cardiomyocyte pyroptosis in the setting of MI and suggest CPAL as a new therapeutic target to protect cardiomyocytes against ischemic injury in infarcted hearts.

Model-based offline reinforcement learning framework for optimizing tunnel boring machine operation

Research on automation and intelligent operation of tunnel boring machine(TBM)is receiving more and more attention,benefiting from the increasing construction data.However,most studies on TBM operations optimization were trained by the labels of human drivers’decisions,which were subjective and stochastic.As a result,the control parameters suggested by these models could hardly surpass the performance of a human driver,even the possibility of subjective incorrect decisions.Considering that the geomechanical feedback to TBM under drivers’actions is objective,in this paper,a transformer-based model called the geological response for tunnel boring machine(GRTBM),is proposed to learn the relationship between operation-adjust and TBM monitoring changes.Additionally,with the model-based offline reinforcement learning,this paper provided a novel approach to optimizing the TBM excavation operations.The decision processes,recorded in the Yin-song TBM project for a waterway tunnel in Jilin Province of China,were used for the validation of the model.By adopting an implicit perception of geological conditions in the GRTBM model,the suggested method achieved the desired state within a single action,greatly outperformed the practical adjustments where 500 s were taken,revealing the fact that the proposed model has the potential to surpass the capability of human beings.

自然保护区生物标本资源共享子平台红外相机数据库建设进展

红外相机技术在野生动物调查研究中得到广泛应用,其发展和普及为中国自然保护地生物多样性保护带来了诸多机会。为进一步推广该技术在我国自然保护地野生动物监测中的应用,中国林业科学研究院森林生态环境与保护研究所在自然保护区生物标本资源共享子平台增设野生动物红外相机数据库专栏,并通过门户网站"中国自然保护区生物标本资源共享平台"(http://www.papc.cn/)对外发布,向公众开放,可以随时查阅、下载信息。本文重点介绍了该平台的野生动物红外相机数据库建设进展,包括所监测的自然保护区、监测方案、数据规范存储、标准化分析、成果介绍、工作计划等内容。2010–2019年间,该平台使用红外相机调查技术在全国13个不同类型的保护地开展兽类和鸟类资源调查,累计27.25万个有效工作日,共拍摄到8.41万张独立图像,经鉴定有80种野生兽类和200种野生鸟类,并利用这些数据对野生动物行为、稀有物种探测、人为干扰,以及气候变化影响等方面进行研究,取得了重要的阶段性成果。下一步,子平台牵头单位将筹建自然保护地红外相机数据共享平台,制定红外相机调查设计、监测技术、数据格式等统一标准化方案,逐步完善我国自然保护地野生动物红外相机监测网络。

“在哪里”和“有多少”? 中国雪豹调查与空缺

雪豹(Panthera uncia)分布广泛且调查难度较大,全世界的雪豹研究面临的首要问题是雪豹基础数据的缺乏。本文通过检索1980至2018年已发表的含有中国境内雪豹分布和密度信息的中英文文章共35篇,从中提取出雪豹的分布与密度信息,其中含有密度估计的文献18篇。同时,来自雪豹调查的15位一线成员通过填写表格和问卷的形式提供了28个地块上未发表的雪豹密度调查信息。基于此,我们逐一分析了各省份已有的雪豹调查现状和存在的调查空缺,发现雪豹分布调查的两大空白区域主要存在于与吉尔吉斯斯坦接壤的西天山地区和西藏南部的冈底斯–念青唐古拉山山脉和喜马拉雅山脉。相对我国雪豹栖息地总面积,有过密度估算的面积仅占1.7%,仍然处于刚刚起步的阶段,并且已有的密度调查几乎都是在质量较好的雪豹栖息地内进行的。今后除了需要继续努力收集汇总已有的调查结果,仍然需要在雪豹分布区(特别是空缺区域)内增加调查。

国家公园生态系统完整性评价研究进展

建立国家公园可促进生态环境和生物多样性的保护,而国家公园生态系统完整性评价对于维持生态系统平衡、生态系统健康、生物多样性以及典型生态系统的完整性具有重要意义。本文介绍了生物完整性指数评价体系(Index of Biotic Integrity, IBI)、三级法评估框架(Three Level Approach, TLA)和生态系统完整性评估框架(EcosystemIntegrityAssessmentFramework,EIAF)三种国家公园生态系统完整性评价方法,其中生物完整性指数评价体系基于高强度的野外调查和室内实验分析,虽然花费大、耗时长以及生物鉴定专业性要求较高,但评价结果准确可靠;三级法评估框架分为三个级别,即远程型评价(RemoteAssessment)、快速型评价(Rapid Assessment)和密集型评价(IntensiveAssessment),在评价独立且较为复杂的生态系统完整性时具有极大的灵活性;生态系统完整性评估框架吸取了生物完整性指数评价体系和三级法评估框架的优点,扩充了评价体系的指标,优化了生态系统完整性评价计分统计方法,是目前最为成熟的评价方法之一。同时,本文也探讨了目前国家公园生态系统完整性评价研究中存在的一些问题,如评价指标不全、评价形式单一和评价方法主观性较强等。作者指出,国家公园生态系统完整性的研究需要注重自然–经济–社会的结合与统一,加强社会经济可持续发展与人类健康等方面的研究,挖掘外来入侵物种与生态环境之间的关系,继续寻找能够反映生态系统完整性状态和变化趋势的新的指示物种,进而制定统一标准的评价方法体系。

The chimeric gene atp6c confers cytoplasmic male sterility in maize by impairing the assembly of the mitochondrial ATP synthase complex

Cytoplasmic male sterility(CMS)is a powerful tool for the exploitation of hybrid heterosis and the study of signaling and interactions between the nucleus and the cytoplasm.C-type CMS(CMS-C)in maize has long been used in hybrid seed production,but the underlying sterility factor and its mechanism of action remain unclear.In this study,we demonstrate that the mitochondrial gene atp6c confers male sterility in CMS-C maize.The ATP6C protein shows stronger interactions with ATP8 and ATP9 than ATP6 during the assembly of F1F0-ATP synthase(F-type ATP synthase,ATPase),thereby reducing the quantity and activity of assem-bled F_(1)F_(o)-ATP synthase.By contrast,the quantity and activity of the F1'component are increased in CMS-C lines.Reduced F1F0-ATP synthase activity causes accumulation of excess protons in the inner membrane space of the mitochondria,triggering a burst of reactive oxygen species(ROS),premature programmed cell death of the tapetai cells,and pollen abortion.Collectively,our study identifies a chimeric mitochondrial gene(ATP6C)that causes CMS in maize and documents the contribution of ATP6C to F1F0-ATP synthase assembly,thereby providing novel insights into the molecular mechanisms of male sterility in plants.

Bird nest-like zinc oxide nanostructures for sensitive electrochemical glucose biosensor

In this research,a novel bird nest-like zinc oxide(BN-ZnO)nanostructures were prepared by a simple solvothermal method.A sensitive electrochemical glucose biosensor was for the first time developed based on the immobilization of glucose oxidase(GOx)on nanostructured BN-ZnO modified electrode.The BN-ZnO nanostructure and the resultant biosensor were characterized by scanning electron microscope,X-ray diffraction spectroscopy,Fourier transform infrared spectroscopy,and electrochemical impedance spectroscopy.BN-ZnO nanostructures have large specific surface area and can load large amounts of GOx molecules.Meanwhile,BN-ZnO provides an excellent microenvironment to retain the native bioactivity of enzymes and to promote direct electron transfer between GOx and electrode surface.The proposed biosensor shows a wide linear range of 0.005–1.6 mmol/L,high sensitivity of15.6 mA L mol^(-1)cm^(-2)with a low detection limit of 0.004 mmol/L.The resulting biosensor also shows excellent selectivity,acceptable stability and reproducibility,and can be successfully applied in the detection of glucose in human serum samples at-0.37 V.

3D reconstruction and automatic leakage defect quantification of metro tunnel based on SfM-Deep learning method

Various structural defects deteriorate tunnel operation status and threaten public safety.Current tunnel inspection methods face problems of low efficiency,high equipment expense,and difficult data management.Combining the deep learning model and the 3D reconstruction method based on structure from motion(SfM),this paper proposes a novel SfM-Deep learning method for tunnel inspection.The high-quality 3D tunnel model is constructed by using images taken every 1 m along the longitudinal direction.The instance segmentation of leakage in longitudinal images is realized using the mask region-based convolutional neural network deep learning model.The SfM-Deep learning method projects the texture of the images after defect recognition to the 3D model and realizes the visualization of leakage defects.By projecting the model to the design cylindrical surface and expanding it,the tunnel leakage area is quantified.Through its practical application in a Shanghai metro shield tunnel,the reliability of the proposed method was verified.The novel SfM-Deep learning method can help engineers efficiently carry out intelligent tunnel detection.

Novel SfM-DLT method for metro tunnel 3D reconstruction and Visualization

Metro tunnels play a crucial role in urban transportation.However,with growing tunnel operation periods,defects,and large deformations appearing,these are influencing tunnel structural performance and threatening public safety.Three-dimensional(3D)tunnel reconstruction is an effective way to highlight tunnel conditions and provide a basis for engineering management and maintenance.However,the current methods of tunnel 3D reconstruction do not sufficiently combine the qualitative and quantitative characteristics of tunnel states.In this study,a novel method for metro tunnel 3D reconstruction based on structure from motion(SfM)and direct linear transformation(DLT)is proposed.The dimensionless 3D reconstruction point cloud acquired through the SfM method showcases the qualitative characteristics(such as leakage and pipelines)of the tunnel state.The close-range photogrammetry DLT method provides scale information missing from the SfM method and quantitative characteristics(such as profile deformation)of the tunnel state.The SfM-DLT method was tested in a Shanghai metro tunnel,and proved to be feasible and promising for future tunnel inspections.

Study on disc cutter chipping of TBM based on field data and particle flow code simulation

Using tunnel boring machines to excavate high-strength intact rock masses is becoming more common.Due to the interactions between disc cutters and rocks,abnormal wear of disc cutters,especially cutter chipping,has become a common phenomenon.Existing research has mainly focused on normal wear of disc cutters without addressing abnormal wear cases.This study used the disc cutter consumption data of a tunnel project in China to investigate the abovementioned problem based on field research.According to the fail-ure patterns and fracture surface characteristics,the cutter chipping patterns were mainly categorized into four types:granule chipping,patch chipping,primary collapse,and secondary collapse.To further simulate the evolution of disc cutter chipping,based on the linear plastic bond model,a new contact model called the modified plastic bond(MPB)model was proposed to solve the metal simulation prob-lem in Particle Flow Code software.To this end,a set of uniaxial tensile and compressive tests were initially conducted to verify the applicability of the MPB model.Then,a series of three-dimensional rock-cutting simulation tests were conducted to reflect the evolu-tionary processes involved in each type of cutter chipping.The cutter chipping mechanism and morphological characteristics were clas-sified and summarized in detail.The results revealed that the cutting speed and penetration growth led to a rising trend in the probability and intensity of the cutter chipping.The presence of initial defects also induced an adverse effect on the service life of the cutter.The results indicated suitable working conditions for the cutter and suggested ways to control tunneling parameters and avoid frequent cutter chipping cases.

Shadow and photon sphere of black hole in clouds of strings and quintessence

In this study,we investigate the shadow and photon sphere of the black bole in clouds of strings and quintessence with static and infalling spherical accretions.We obtain the geodesics of the photons near a black hole with different impact parameters b to investigate how the string cloud model and quintessence influence the specific intensity by altering the geodesic and the average radial position of photons.In addition,the range of the string cloud parameter a is constrained to ensure that a shadow can be observed.Moreover,the light sources in the accretion follow a normal distribution with an attenuation factorγ,and we adopt a model of the photon emissivity j(v_(e))to obtain the specific intensities.Furthermore,the shadow with static spherical accretion is plotted,which demonstrates that the apparent shape of the shadow is a perfect circle,and the value ofγinfluences the brightness of the photon sphere.Subsequently,we investigate the profile and specific intensity of the shadows with static and infalling spherical accretions,respectively.The interior of the shadows with an infalling spherical accretion will be darker than that with the static spherical accretion,and the specific intensity with both static and infalling spherical accretions gradually converges.