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Individual stages of bacterial dichloromethane degradation mapped by carbon and chlorine stable isotope analysis

Journal of Environmental Sciences 2019年第4期31卷 147-160页

作者： Maria L.Torgonskaya Anatoly M.Zyakun Yuri A.Trotsenko kestutis S.Laurinavichius steffen kümmel Stéphane Vuilleumier Hans H.Richnow Laboratory of Radioactive Isotopes G.K.Skryabin Institute of Biochemistry and Physiology of MicroorganismsFRC Pushchino Center for Biological ResearchRussian Academy of Sciences Laboratory of Mass Spectrometry G.K.Skryabin Institute of Biochemistry and Physiology of MicroorganismsFRC Pushchino Center for Biological ResearchRussian Academy of Sciences Department of Isotope Biogeochemistry Helmholtz Centre for Environmental Research-UFZ Université de Strasbourg CNRS

The fractionation of carbon and chlorine stable isotopes of dichloromethane(CH_2Cl_2,DCM)upon dechlorination by cells of the aerobic methylotroph Methylobacterium extorquens DM4 and by purified DCM dehalogenases of the glutathione S-transferase family was *** effects for individual steps of the multi-stage DCM degradation process,including transfer across the cell wall from the aqueous medium to the cell cytoplasm,dehalogenase binding,and catalytic reaction,were *** observed carbon and chlorine isotope fractionation accompanying DCM consumption by cell supensions and enzymes was mainly determined by the breaking of C\Cl bonds,and not by inflow of DCM into *** isotope effects of DCM dehalogenation were initially masked in high density cultures,presumably due to inverse isotope effects of non-specific DCM oxidation under conditions of oxygen *** cofactor supply remarkably affected the correlation of variations of DCM carbon and chlorine stable isotopes(Δδ^(13)C/Δδ^(37)Cl),increasing corresponding ratio from 7.2–8.6 to 9.6–10.5 under conditions of glutathione *** suggests that enzymatic reaction of DCM with glutathione thiolate may involve stepwise breaking and making of bonds with the carbon atom of DCM,unlike the uncatalyzed reaction,which is a one-stage process,as shown by quantum-chemical modeling.

关键词： Dichloromethane(DCM) Microbial degradation Aerobic methylotrophic bacteria Dichloromethane dehalogenase Carbon and chlorine isotopic fractionation

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Many faces of neuronal activity manipulation in Drosophila

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Neural Regeneration Research 2025年第9期20卷 2574-2576页

作者： Amber krebs steffen kautzmann Christian klämbt Institut für Neuro-und Verhaltensbiologie MünsterGermany

Animals exhibit complex responses to external and internal *** information is computed by interconnected neurons that express numerous ion channels,which modulate the neuronal membrane *** can neuronal activity orchestrate complex motor patterns or allow learning from previous experience?To answer such questions,we need the ability not only to record,but also to modulate neuronal activity in both space(e.g.,neuronal subsets)and time.

关键词： manipulation potential. neuronal

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基于自由空间传播的光子极限学习机设计与分析

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光学学报 2025年第03期 180-187页

作者：徐志宏 Schoenhardt steffen 陈希顾敏 Goi Elena 上海理工大学智能科技学院上海理工大学光子芯片研究院

极限学习机（ELM）是一种机器学习范式，在模型中，大多数连接通过随机初始化的非线性隐藏层建立，只有一小部分权重在下采样过程后的训练期间被调整。该模型的主要优点是显著减少了训练时间，用简单的岭回归取代了耗时的误差反向传播... 详细信息

极限学习机（ELM）是一种机器学习范式，在模型中，大多数连接通过随机初始化的非线性隐藏层建立，只有一小部分权重在下采样过程后的训练期间被调整。该模型的主要优点是显著减少了训练时间，用简单的岭回归取代了耗时的误差反向传播。但在电子ELM中，模型性能严重依赖于隐藏层中的节点数量，从而使用大量内存。因此，用光学平台代替电子计算是一种理想的解决方案。通过部署随机散射体，可以被动地实现大规模隐藏节点，同时具有非线性的可能性。虽然光学方案具有这种潜力，但关于光学ELM的研究尚未充分探索其在速度、非线性和并行性方面的能力。为了解决这个问题，搭建了ELM的光学框架（光学ELM），并研究了投影和成像光束路径中的变焦对光学ELM的作用。在实验过程中存在光学像差、误差及缺陷，在光学ELM的背景下将其充当为随机分量，对应了数字极限学习机中的随机传输矩阵。目标是设计一个易于部署的光学极限学习机，不需要对输入和输出数据进行复杂的处理，而是通过光域中的被动传播实现随机投影。该方法旨在简化系统架构，同时利用光学技术的优势实现高效并行计算。

关键词：光计算极限学习机光神经网络模拟计算神经形态光子学

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Flash X-ray cinematography analysis of dwell and penetration of smallcaliber projectiles with three types of SiC ceramics

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Defence Technology（防务技术） 2016年第3期12卷 277-283页

作者： Elmar STRASSBURGER steffen BAUER steffen WEBER Heiner GEDON Fraunhofer Institute for High-Speed Dynamics Ernst-Mach-Institute(EMI)Am Christianswuhr 279400 KandernGermany DLR–German Aerospace Center Institute of Structures and DesignPfaffenwaldring 38-4070569 StuttgartGermany WIWeB–Bundeswehr Research Institute for Materials Fuels and LubricantsInstitutsweg 185435 ErdingGermany

In order to improve the performance of ceramic composite armor it is essential to know the mechanisms during each phase of the projectile–target interaction and their influence on the penetration *** the view on the crater zone and the tip of a projectile penetrating a ceramic is rapidly getting obscured by damaged material,a flash X-ray technique has to be applied in order to visualize projectile *** this purpose,usually several flash X-ray tubes are arranged around the target and the radiographs are recorded on *** EMI a flash X-ray imaging method has been developed,which provides up to eight flash radiographs in one experiment.A multi-anode 450 k V flash X-ray tube is utilized with this *** radiation transmitted through the target is then detected on a fluorescent *** fluorescent screen converts the radiograph into an image in the visible wavelength range,which is photographed by means of a high-speed *** technique has been applied to visualize and analyze the penetration of 7.62 mm AP projectiles into three different types of Si C *** commercial Si C grades and MICASIC(Metal Infiltrated Carbon derived Si C),a C-Si Si C ceramic developed by DLR,have been *** influences,not only of the ceramic but also the backing material,on dwell time and projectile erosion have been *** curves have been determined and their relevance to the ballistic resistance is discussed.

关键词： Ballistic resistance Dwell Flash X-ray cinematography SiC ceramics

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Spatial Industrial Accident Exposure and Social Vulnerability Assessment of Hazardous Material Sites,Chemical Parks,and Nuclear Power Plants in Germany

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International Journal of Disaster Risk Science 2023年第2期14卷 223-236页

作者： Alexander Fekete steffen Neuner Institute of Rescue Engineering and Civil Protection TH Köln-University of Applied Sciences50679CologneGermany

Industrial accidents have shown that many people can be affected,such as in Seveso,Italy,in *** accidents in nuclear power plants have also led to fatalities and *** better guide preparedness against and mitigation of industrial accidents,an assessment is necessary to evaluate hazard exposure and the type of potentially vulnerable social groups that need to be taken into *** study conducted a spatial assessment of three types of industrial facilities in Germany:facilities registered under the Seveso Directive,chemical parks,and nuclear power *** method consisted of a spatial assessment using a Geographic Information System of exposure around hazardous sites registered under the S eveso Directive in Germany and of census data to analyze social *** analyzed included industrial accidents and *** results revealed that most industrial sites are in urban areas and that population density,the numbers of foreigners,and smaller housing unit sizes are higher in close proximity to these *** buffer zones analyzed in circles between 1 and 40 km show a decreasing vulnerability with more *** can guide emergency management planners and other stakeholders to better prepare for major accidents and better devise disaster risk reduction strategies specifically for different social groups.

关键词： Germany Industrial disaster risk Seveso directives Seveso sites Social vulnerability

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Analysis of genetic diversity and phylogenetic relationships among red jungle fowls and Chinese domestic fowls

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Science China(Life Sciences) 2008年第6期51卷 560-568页

作者： steffen WEIGEND Institute for Animal Breeding Federal Agricultural Research Centre

Genetic diversity and phylogenetic relationships among 568 individuals of two red jungle fowl subspe- cies (Gallus gallus spadiceus in China and Gallus gallus gallus in Thailand) and 14 Chinese domestic chicken breeds were evaluated with 29 microstaellite loci, the genetic variability within population and genetic differentiation among population were estimated, and then genetic diversity and phylogenetic relationships were analyzed among red jungle fowls and Chinese domestic fowls. A total of 286 alleles were detected in 16 population with 29 microsatellite markers and the average number of the alleles observed in 29 microsatellite loci was 9.86±6.36. The overall expected heterozygosity of all population was 0.6708±0.0251, and the number of population deviated from Hardy-Weinberg equilibrium per locus ranged from 0 to 7. In the whole population, the average of genetic differentiation among population, measured as FST value, was 16.7% (Pken-Luyuan chicken pair) and 0.330 (G. gallus gallus-Gushi chicken pair). The Nm value ranged from 0.533 (between G. gallus gallus and Gushi chicken) to 5.833 (between Xiaoshan chicken and Luyuan chicken). An unrooted consensus tree was constructed using the neighbour-joining method and the Reynolds' genetic distance. The heavy-body sized chicken breeds, Luyuan chicken, Xiaoshan chicken, Beijing Fatty chicken, Henan Game chicken, Huainan Partridge and Langshan chicken formed one branch, and it had a close genetic relationship between Xiaoshan chicken-Luyuan chicken pair and Chahua chicken-Tibetan chicken pair. Chahua chicken and Tibetan chicken had closer genetic relationship with these two subspecies of red jungle fowl than other domestic chicken breeds. G. gallus spadiceus showed closer phylogenetic relati

关键词： red jungle fowl domestic fowl microsatellite genetic diversity phylogenetic relationship

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Comment on “Evidence for Mesoproterozoic collision,deep burial and rapid exhumation of garbenschiefer in the Namaqua Front,South Africa” by Valby Van Schijndel,David ***,Robert Anczkiewicz,Anders Schersten,Geoscience Frontiers,Volume 11,Issue 2,Pag

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Geoscience Frontiers 2020年第5期11卷 1889-1894页

作者： steffen H.Buttner Department of Geology Rhodes University6139Makhanda(Grahamstown)South Africa

In their recent publication Van Schijndel et al.(2020) present new age data and P-T analysis from the eastern margin of the Namaqua Sector of the Namaqua Natal Metamorphic *** authors claim to provide evidence for the... 详细信息

关键词： Province. burial eastern

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Nutrient retention and release in coarse woody debris of three important central European tree species and the use of NIRS to determine deadwood chemical properties

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Forest Ecosystems 2018年第3期5卷 296-310页

作者： steffen Herrmann Jurgen Bauhus Faculty of Environment and Natural Resources University of Freiburg Tennenbacherstr.4D-79106Freiburg i.Br.Germany Thunen Institute of Forest Ecosystems Alfred-M611er-Strabe 1Haus41/4216225EberswaldeGermany

Background: Coarse woody debris(CWD) is very important for forest ecosystems, particularly for biodiversity and carbon storage. Its relevance as a possible reservoir and source of nutrients is less clear, especially in central ***: Based on a chronosequence of known ages of logs, we analyzed the nutrients stored in CWD of Fagus sylvatica, Picea abies, and Pinus sylvestris at different sites in Germany. To quantify nutrient concentrations, we assessed the use of Near Infrared Reflectance Spectroscopy(NIRS) to determine the chemical properties of ***: NIRS models were suitable to predict concentrations of C, N, P, lignin and extractives. Concentrations of most nutrients increased with mass loss, with the exception of potassium, which decreased for beech and pine and remained relatively constant for spruce. The highest nutrient concentrations(N, P, S, Ca and Mn, except Mg and k) were generally observed in highly decomposed spruce logs. The net effect of decreasing CWD mass and increasing nutrient concentrations was either a decreasing(N, P and k in beech; P, Mg, k and Mn in pine), constant(S, Ca and Mg in beech; N, S and Ca in pine) or increasing amount of nutrients(N, P, S and Ca in spruce; Mn in beech) in the logsover the course of decomposition. The C/N ratio decreased for all tree species, most markedly for spruce from ca. 1000 at the beginning of the decomposition process to 180 at 36 years. The N/P ratio converged to a value of about 30 forall three species. Lignin concentrations increased for spruce and beech and remained constant for ***: Our results indicate that most nutrients remain in CWD for long periods. Nutrients may be used and cycled by microorganisms within CWD, but with the exception of P(in beech), Mg(in pine) and k(in beech and pine), there appears to be little net nutrient export until two thirds of the mass is lost. Instead, N, P, S and Ca were accumulated in spruce logs, indicating that CWD became a net sink rathe

关键词： CWD NIRS Decay Carbon F.sylvatica P.abies P.sylvestris

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Real-time estimation of the structural utilization level of segmental tunnel lining

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Underground Space 2024年第4期17卷 132-145页

作者： Nicola Gottardi steffen Freitag Gunther Meschke Institute for Structural Mechanics Ruhr University BochumBochum 44801Germany Institute for Structural Analysis Karlsruhe Institute of TechnologyKarlsruhe 76131Germany

Over the last decades,an expansion of the underground network has been taking place to cope with the increasing amount of moving people and *** a consequence,it is of vital importance to guarantee the full functionality of the tunnel network by means of preventive maintenance and the monitoring of the tunnel lining state over time.A new method has been developed for the real-time prediction of the utilization level in tunnel segmental linings based on input monitoring *** new concept is founded on a framework,which encompasses an offline and an online *** the former,the generation of feedforward neural networks is accomplished by employing synthetically produced *** element simulations of the lining structure are conducted to analyze the structural response under multiple loading *** scenarios are generated by assuming ranges of variation of the model input parameters to account for the uncertainty due to the not fully determined in situ *** and target quantities are identified to better assess the structural utilization of the *** latter phase consists in the application of the methodological framework on input monitored data,which allows for a real-time prediction of the physical quantities deployed for the estimation of the lining *** approach is validated on a full-scale test of segmental lining,where the predicted quantities are compared with the actual ***,it is investigated the influence of artificial noise added to the training data on the overall prediction performances and the benefits along with the limits of the concept are set out.

关键词： Segmental lining Artificial neural networks Structural utilization level Real-time prediction Structural health monitoring Monitoring data

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Separating polydisperse particles using electrostatic precipitators with wire and spiked-wire discharge electrode design

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Particuology 2018年第3期16卷 10-17页

作者： Soren Sander steffen Gawor Udo Fritsching Process Engineering Stiftung Institut ffir Werlcstofftechnik Badgasteiner Strasse 3 28359 Bremen Germany Particles and Process Engineering University of Bremen Bibliothekstrasse 1 28359 Bremen. Germany

Numerical simulations of electrostatic precipitators featuring wire and spiked electrode designs were performed to determine particle behavior and separation efficiency. The applied-voltage mechanism that alters the flow structure of particles through ionic winds and mean electric fields are revealed. Numeri- cal studies throughout the past years have shown these structures for channel and pipe configurations. However, less attention was given to field averaging for the ni,~r-product and electric field. Our study focuses on this averaging and illustrates relevant differences between multidimensional setups concern- ~ng these fields. Turbulence was modeled using the Reynolds-averaged Navier-Stokes equations with a second-order Reynolds-stress-model closure. A high three-dimensionality of the ionic wind-induced turbulence is presented. This leads to an increase in the submicron-particle precipitation rate. The results confirm the dependence of separation efficiency on particle density and permittivity, thereby showing the advantages of spiked wires compared with wire-plate setups used in electrostatic precipitators.

关键词： Electro-hydrodynamic CFD simulation Electrostatic particle precipitation Electrode design Collection efficiency

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