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Antidiabetic profiling of veramycins,polyketides accessible by biosynthesis,chemical synthesis and precursor-directed modification

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Organic Chemistry Frontiers 2022年第6期9卷 1604-1615页

作者： Denis Dardić Nils Böhringer Alberto Plaza Florian Zubeil Juliane Pohl Svenja Sommer Leo Padva Jonathan Becker Maria A.Patras mona-katharina bill Michael Kurz Luigi Toti Sven W.Görgens Sören M.M.Schuler Andrébillion Oliver Schwengers Paulus Wohlfart Alexander Goesmann Norbert Tennagels Andreas Vilcinskas Peter E.Hammann Till F.Schäberle Armin Bauer Fraunhofer Institute for Molecular Biology and Applied Ecology(IME) Branch for Bioresources35392 GießenGermany Justus-Liebig-University Gießen 35392 GießenGermany Sanofi-Aventis Deutschland GmbH R&D Integrated Drug Discovery65926 Frankfurt am MainGermany Sanofi-Aventis Deutschland GmbH R&D German Hub65926 Frankfurt am MainGermany German Center of Infection Research(DZIF) Partner Site Gießen-Marburg-Langen35392 GießenGermany

Seven new polyketides,termed veramycins,were isolated from a Streptomyces *** the Sanofi microbial strain collection along with their known congeners NFAT-133 and *** A,anα-pyrone congener of TM-123 and NFAT-133 showed an increased baseline deoxy-glucose uptake in the absence of insulin in a modified L6 rat skeletal muscle cell line(L6 GLUT4 AS160-like cells).In addition,both compounds slightly increased the sensitivity to insulin in this cell *** syntheses of NFAT-133,TM-123 and veramycin A were accomplished starting from a central building block,which bears the three contiguous stereogenic centers of this polyketide *** approach enables an efficient,selective and flexible access to all possible isomers of the stereotriad for further exploration of this series as a potential anti-diabetic lead structure as exemplified by the synthesis of an NFAT-133 ***,the corresponding biosynthetic gene cluster(BGC)was identified by genome sequencing and gene *** on feeding experiments,a biosynthetic pathway was proposed,which enabled access to new veramycin A analogs by precursor-directed biosynthesis.

关键词： synthesis directed isomers

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Development of a six drillhead roof bolting machine

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International Journal of Mining Science and Technology 2017年第1期27卷 37-41页

作者： Kyslinger bill A. J.H.Fletcher&Co. HuntingtonWV25722USA

In underground mining, machine design is predominantly dictated by mine conditions and individual customer desires. In partnership with Foresight Energy, J. H. Fletcher & Company was tasked to design and manufacture a new roof bolting machine with six independent drilling apparatus on board capable of drilling and bolting the roof and ribs with material handling. The objective was to produce a machine capable of drilling and installing six bolts simultaneously with a limited number of operators. The goal of the mine is to decrease the time to bolt a cut to improve the safety level of the current roof bolting method, improve efficiency and to improve the bottom line cost of entry development. The customer wanted four drills at the front of the machine dedicated to installing roof bolts and then another two drills behind them dedicated to rib bolts. This dictated the requirement of latched controls, which would allow the operator to start drilling one hole and then latch the controls to be able to move on to the *** result of the design is a machine with a single platform and six independent masts with drillheads:four masts strictly for drilling and installing roof bolts on the front of the platform and two masts on the back of the platform for rib bolts. The controls at each operator's station include a latch control for drilling. The six-head roof bolter allows fewer operators to drill and install roof and rib bolts, which in turn lowers the miners' roof exposure per cut. This design reduces the operator's exposure from the inherent pinch points and rotary hazards once he has engaged the latch drilling. Therefore, the machine will help to decrease the time to bolt a cut, improving productivity while enhancing the ability to operate the machine safely.

关键词： Roof bolter MiningSix-head FletcherLatched Material handling

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Design and analyses of open-ended pipe piles in cohesionless soils

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Frontiers of Structural and Civil Engineering 2016年第1期10卷 22-29页

作者： Yuan GUO Xiong (bill) YU Department of Civil Engineering Case Western Reserve University 2104 Adelbert Road Bingham 260 Cleveland OH 44106-7201USA

Large open-ended pipe pile has been found to be advantageous for use in transportation projects. The current design method, however, is not adequately developed. To close this practice gap, this paper first summarized different design methods for open-ended pipe piles in sandy soils. A major factor for all the design codes is to properly account for the formation and effects of soil plug. The comparison indicates that there is a large variation in the base capacity evaluation among different methods due to the complex behaviors of soil plug. To close the knowledge gap, discrete element method （DEM） was used to simulate the soil plugging process and provide insight on the plugging mechanism. The simulation results show that the arching effect significantly increases the internal unit shear resistance along pipe piles. The porosity distribution and particle contact force distribution from DEM model indicate a large stress concentration occurs at the bottom of the soil plug. Besides, nearly 90% of the plug resistance is provided by the bottom half portion of the soil column. The soil-pile friction coefficient has a significant effect on the magnitude of plug resistance, with the major transition occurred for friction coefficient between 0.3 and 0.4.

关键词： open-ended pipe pile soil plug DEM base capacity

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Image analyses for video-based remote structure vibration monitoring system

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Frontiers of Structural and Civil Engineering 2016年第1期10卷 12-21页

作者： Yang YANG Xiong (bill) YU Department of Electrical Engineering and Computer Science Case Western Reserve University 10900 Euclid Avenue Bingham203d Cleveland OH 44106-7201 USA Department of Civil Engineering Case Western Reserve University 10900 Euclid Avenue Bingham 210 Cleveland OH 44106-7201 USA

Video-based vibration measurement is a cost-effective way for remote monitoring the health conditions of transportation and other civil structures, especially for situations where accessibility is restricted and does not allow installation of conventional monitoring devices. Besides, video-based system is global measurement. The technical basis of video-based remote vibration measurement system is digital image analysis. Comparison of the images allow the field of motion to be accurately delineated. Such information is important to understand the structure behaviors including the motion and strain distribution. This paper presents system and analyses to monitor the vibration velocity and displacement field. The performance is demonstrated on a testbed of model building. Three different methods （i.e., frame difference method, particle image velocimetry, and optical Flow Method） are utilized to analyze the image sequences to extract the feature of motion. The Performance is validated using accelerometer data. The results indicate that all three methods can estimate the velocity field of the model building, although the results can be affected by factors such as background noise and environmental interference. Optical flow method achieved the best performance among these three methods studied. With further refinement of system hardware and image processing software, it will be developed into a remote video based monitoring system for structural health monitoring of transportation infrastructure to assist the diagnoses of its health conditions.

关键词： structure health monitoring velocity estimation frame difference PIV optical-flow method

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Physical science bill W. Tillery.

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2002年

作者： bill W. Tillery.

来源：畅想之星图书光盘版（南... 评论

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Influence of particle shape on the erodibility of non-cohesive soil： Insights from coupled CFD-DEM simulations

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Particuology 2018年第4期16卷 12-24页

作者： Yuan Guo Yang Yang Xiong (bill) Yu Department of Civil Engineering Case Western Reserve University 2104 Adelbert Road Bingharn 269 Cleveland OH 44106-7201 USA Department of Electrical Engineering and Computer Science Case Western Reserve University 2104 Adelbert Road Bingharn 203D Cleveland OH 44106-7201 USA Departrnent of Civil Engineering Case Western Reserve University 2104 Adelbert Road Bingharn 206 Cleveland OH 44106- 7201 USA

Soil erosion is a critical process that is being studied in soil science, hydraulic engineering, and geotech- nical engineering. Among many societal and environmental impacts, soil erosion is a major cause for the failures of bridges. The erodibility of soil is determined by its physical and geochemical properties and is also affected by surrounding biological activities. In most of the current models for soil erosion, erodibility of non-cohesive soil is characterized by its median grain size （Dso）, density, and porosity. The contribution to erodibility of the irregular shape of soil grains, which plays an important role in the mechanical and hydraulic properties of coarse-grained soils, is generally ignored. In this paper, a coupled computational fluid dynamics and discrete element method model is developed to analyze the influence of the shape of sand grain on soil erodibility. A numerical model for the drag force on spherical and non-spherical particles is verified by using the results from physical free settling experiments. Erosion of sand grains of different shapes is simulated in a virtual erosion function apparatus, a laboratory device used to mea- sure soil erodibility. The simulation results indicate that the grain shape has major effects on erodibility. Spherical particles do not show a critical velocity because of their low rolling resistance, but a critical velocity does exist for angular particles owing to grain interlocking. The erosion rate is proportional to the flow velocity for both spherical and non-spherical particles. The simulation result for angular particle erosion is fairly consistent with the experimental observations, implying that grain shape is an important factor affecting the erodibility of non-cohesive soils.

关键词： CFD-DEM Soil erosion Grain shape Erodibility of coarse-grained soil Erosion function apparatus mode

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Comparison between gradient based UCODE2005 and the ensemble Kalman Filter for transient groundwater flow inverse modeling

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Science China Earth Sciences 2017年第5期60卷 899-909页

作者： TONG JuXiu bill X HU YANG JinZhong Key Laboratory of Groundwater Cycle and Environment Evolution (China University of Geosciences) Ministry of Education Beijing 100083 China School of Water Resources and Environment China University of Geosciences Beijing 100083 China Department of Earth Ocean and Atmospheric Science/Geological Sciences 108 Carraway Building 909 Antarctic Way Florida State University Tallahassee Florida 32306 USA State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China

Gradient based UCODE_2005 and data assimilation based on the Ensemble Kalman Filter(EnKF) are two different inverse methods. A synthetic two-dimensional flow case with four no-flow boundaries is used to compare the UCODE_2005 with the Ensemble Kalman Filter(EnKF) for their efficiency to inversely calculate and calibrate a hydraulic conductivity field based on hydraulic head data. A zonal, random heterogeneous conductivity field is calibrated by assimilating the time series of heads observed in monitoring wells. The study results indicate that the two inverse methods, UCODE_2005 and EnKF, could be used to calibrate the hydraulic conductivity field to a certain degree. More available observations and information about the conductivity field, more accurate inverse results will be obtained for the UCODE_2005. On the other hand, for a realistic zonal heterogeneous hydraulic conductivity field, EnKF can only efficiently determine the hydraulic conductivity field at the first several assimilated time steps. The results obtained by the UCODE_2005 look better than those by the EnKF. This is possibly due to the fact that the UCODE_2005 uses observed head data at every time step, while EnKF can only use observed heads at first several steps due to the filter divergence problem.

关键词： Inverse methods UCODE2005 Ensemble Kalman Filter Heterogeneous hydraulic conductivity Filter divergence

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Interlayer shear of nanomaterials:Graphene–graphene,boron nitride–boron nitride and graphene–boron nitride

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Acta Mechanica Solida Sinica 2017年第3期30卷 234-240页

作者： Yinfeng Li Weiwei Zhang bill Guo Dibakar Dattac Department of Engineering Mechanics School of Naval Architecture Ocean and Civil Engineering (State Key Laboratory of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration) Shanghai Jiao Tong University Shanghai 200240 China Department of Materials Science and Engineering University of Pennsylvania Philadelphia PA 19104 USA Department of Mechanical and Industrial Engineering Newark College of Engineering New Jersey Institute of Technology Newark NJ 07102 USA Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education Nanjing University of Aeronautics and Astronautics Nanjinq 210016 China

In this paper, the interlayer sliding between graphene and boron nitride （h-BN） is studied by molecular dynamics simulations. The interlayer shear force between h-BN/h-BN is found to be six times higher than that of graphene/graphene, while the interlayer shear between graphene/h-BN is approximate to that of graphene/graphene. The graphene/h- BN heterostructure shows several anomalous interlayer shear characteristics compared to its bilayer counterparts. For graphene/graphene and h-BN/h-BN, interlayer shears only exit along the sliding direction while interlayer shear for graphene/h-BN is observed along both the translocation and perpendicular directions. Our results provide significant insight into the interlayer shear characteristics of 2D nanomaterials.

关键词： Friction Interlayer shear Graphene Hexongal boron nitride Molecular dynamics

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A holistic computational model for prediction of clay suspension structure

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International Journal of Sediment Research 2019年第4期34卷 345-354页

作者： Yuan Guo Xiong (bill) Yu Department of Civil Engineering Case Western Reserve University

The formation of clay suspensions involves complex interactions among clay particles subjected to the geochemical environment during the sedimentation process. The structural characteristics have a major influence on the physical and mechanical behavior of the suspension. A modeling framework involving a Discrete Element Method(DEM) model with customized particle mechanical interactions is proposed in this paper for the holistic prediction of the physical structure of clay suspensions. The particle interaction force model is based on the Derjaguin, Landau, Verwey, and Overbeek(DLVO) theory that accounts for electrostatic repulsion, van der Waals attraction, contact repulsion, etc. Kaolinite is used as the model clay to demonstrate the model performance. The surface charge density of kaolinite is obtained through Atomic Force Microscope(AFM) force measurement and is implemented in the particle interaction force model in the subsequent simulations. Influencing factors, such as centrifugal acceleration, ionic concentration, platy structure of particles, and particle size, on the formation of kaolinite suspensions are studied with the numerical model and compare favorably well with the experimental data. This work lays down a unique framework consisting of computational modeling and microscale characterization of clay particles to holistically predict the characteristics of clay suspensions, which paves the basis to model and predict their bulk physical and mechanical behavior.

关键词： Clay suspension Discrete element method DLVO theory Atomic force microscope Kaolinite Surface potential

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Identification of hydraulic conductivity distributions in density dependent flow fields of submarine groundwater discharge modeling using adjoint-state sensitivities

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Science China Earth Sciences 2016年第4期59卷 770-779页

作者： HU bill X CAO YanZhao ZHAO WeiDong BAO Feng School of Water Resources and Environmental Sciences China University of Geosciences Department of Geological Sciences Florida State University Department of Mathematics and Statistics Auburn University School of Mathematics Shandong University

A mathematical optimal control method is developed to identify a hydraulic conductivity distribution in a density dependent flow field. Using a variational method, the adjoint partial differential equations are obtained for the density-dependent state equations used for the saline aquifer water flow. The adjoint equations are numerically solved in through a finite difference method. The developed method is applied to identify the hydraulic conductivity distribution through the numerical solution of an optimal control problem. To demonstrate the effectiveness of the optimal control method, three numerical experiments are conducted with artificial observation data. The results indicate that the developed method has the potential to accurately identify the hydraulic conductivity distribution in a saline water aquifer flow system.

关键词： Variable-density flow Hydraulic conductivity Inverse method Adjoint partial differential equation Submarine groundwater discharge

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