检索结果-南通市图书馆

Microsystems & Nanoengineering 2018年第1期4卷 325-336页

作者： Ketki chawla sebastian c.bürgel Gregor W.Schmidt Hans-Michael Kaltenbach Fabian Rudolf Olivier Frey Andreas Hierlemann ETH Zurich Department of Biosystems Science and EngineeringBio Engineering LaboratoryBaselSwitzerland ETH Zurich Department of Biosystems Science and EngineeringComputational Systems Biology GroupBaselSwitzerland

Growth rate is a widely studied parameter for various cell-based biological *** rates of cell populations can be monitored in chemostats and micro-chemostats,where nutrients are continuously ***,we present an integrated microfluidic platform that enables long-term culturing of non-adherent cells as well as parallel and mutually independent continuous monitoring of(i)growth rates of cells by means of impedance measurements and of(ii)specific other cellular events by means of high-resolution optical or fluorescence *** colonies were grown in a monolayer under culturing pads,which enabled high-resolution microscopy,as all cells were in the same focal *** cell growth and division,cells leaving the culturing area passed over a pair of electrodes and were counted through impedance *** impedance data could then be used to directly determine the growth rates of the cells in the culturing *** integration of multiple culturing chambers with sensing electrodes enabled multiplexed long-term monitoring of growth rates of different yeast strains in *** a demonstration,we modulated the growth rates of engineered yeast strains using *** results indicated that impedance measurements provide a label-free readout method to continuously monitor the changes in the growth rates of the cells without compromising high-resolution optical imaging of single cells.

关键词： impedance continuously culture

A cOMPARATIVE STUDY OF THE INVENTORY SYSTEM WITH SERVIcE FAcILITY AND POSTPONED DEMANDS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science and Systems Engineering 2014年第2期23卷 176-195页

作者： J.sebastian Arockia Jenifer b.Sivakumar School of Mathematics Madurai Kamaraj University

In this article, we present a continuous review （s,S） inventory system with a service facility consisting of finite buffer （capacity N ） and a single server. The customers arrive according to a Poisson process. The individual customer＇s unit demand is satisfied after a random time of service, which is assumed to be exponential. When the inventory level drops to s＇an order for Q（= S-s） items is placed. The lead time of reorder is assumed to be exponential distribution. An arriving customer, who finds the buffer is full, enters into the pool of infinite size or leaves the system according to a bernolli trial. At the time of service completion, if the buffer size drops to a preassigned level L （1 〈 L 〈 N） or below and the inventory level is above s, we select the customers from the pool according to two different policy ： in first policy, with probability p （0 〈 p 〈 1） we select the customer from the head of the pool and we place the customer at the end of the buffer; in the second policy, with p （0 〈 p 〈 1） the customer from the pool is transferred to the buffer for immediate service and after completion of his service we provide service to the customer who is in the buffer with probability one. If at a service completion epoch the buffer turns out to be empty, there is at least one customer in the pool and the inventory level is positive, then the one ahead of all waiting in the pool gets transferred to the buffer, and his service starts immediately. The joint probability distribution of the number of customers in the pool, number of customers in the buffer and the inventory level is obtained in the steady-state case. Various stationary system performance measures are computed and total expected cost rate is calculated. A comparative result of two models is illustrate numerically.

关键词： continuous review inventory system postponed demands service facility finite waiting hall pool with infinite size

How single-cell immunology is benefiting from microfluidic technologies

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2020年第1期6卷 728-741页

作者： Fabien c.Jammes sebastian J.Maerkl Institute of bioengineering School of EngineeringEcole Polytechnique Federale de LausanneLausanneSwitzerland

The immune system is a complex network of specialized cells that work in concert to protect against invading pathogens and tissue *** in this network often result in excessive or absent immune responses leading to allergies,autoimmune diseases,and *** of the mechanisms and their regulation remain poorly *** cells are highly diverse,and an immune response is the result of a large number of molecular and cellular interactions both in time and *** bulk methods are often prone to miss important details by returning population-averaged *** is a need in immunology to measure single cells and to study the dynamic interplay of immune cells with their *** in the fields of microsystems and microengineering gave rise to the field of microfluidics and its application to *** systems enable the precise control of small volumes in the femto-to nanoliter *** controlling device geometries,surface chemistry,and flow behavior,microfluidics can create a precisely defined microenvironment for single-cell studies with spatio-temporal *** features are highly desirable for single-cell analysis and have made microfluidic devices useful tools for studying complex immune *** addition,microfluidic devices can achieve high-throughput measurements,enabling in-depth studies of complex *** has been used in a large panel of biological applications,ranging from single-cell genomics,cell signaling and dynamics to cell–cell interaction and cell migration *** this review,we give an overview of state-of-the-art microfluidic techniques,their application to single-cell immunology,their advantages and drawbacks,and provide an outlook for the future of single-cell technologies in research and medicine.

关键词： fluid network details

Patterning inconsistencies restrict the true potential of dopaminergic neurons derived from human induced pluripotent stem cells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2021年第4期16卷 692-693页

作者： Sameehan Mahajani Mathias bähr sebastian Kügler Department of Neurology University Medical Center GöttingenGöttingenGermany center for Nanoscale Microscopy and Molecular Physiology of the brain at Department of Neurology University Medical Center GöttingenGöttingenGermany Department of Pathology Stanford University School of MedicineStanfordCAUSA

Human induced pluripotent stem cells(hiPScs)are multipotent stem cells genetically reprogrammed using transcription factors,such as Sox2,c-Myc,Oct3/4 and Klf4(Takahashi and Yamanaka,2006)from fibroblasts,derived from either patient or control *** factors are highly expressed in embryonic stem cells,and their overexpression can induce pluripotency in human somatic cells such as *** the generation of hiPScs after reprogramming,these cells can be further differentiated into multiple neuronal cell types by using a strictly designed *** process is known as *** use of these hiPScs derived neurons holds immense potential for researchers to uncover the underpinnings of disease pathophysiology and therefore is considered as a powerful tool.

关键词： potential restrict holds

complex coacervate Materials as Artificial cells

在线全文

学校读者我要写书评

暂无评论

Accounts of Materials Research 2023年第3期4卷 287-298页

作者： Alexander b.cook sebastian Novosedlik Jan c.M.van Hest bio-Organic chemistry Institute for Complex Molecular SystemsEindhoven University of Technology5600 MB EindhovenThe Netherlands

cONSPEcTUS:cells have evolved to be self-sustaining compartmentalized systems that consist of many thousands of biomolecules and metabolites interacting in complex cycles and reaction *** subtle intricacies of these self-assembled structures are still largely *** importance of liquid−liquid phase separation(both membraneless and mem-brane bound)is,however,recognized as playing an important role in achieving biological function that is controlled in time and *** biochemical reactions in vitro has been a success of the last decades,for example,establishment of the minimal set of enzymes and nutrients able to replicate cellular activities like the in vitro transcription translation of genes to *** than this though,artificial cell research has the aim of combining synthetic materials and nonliving macromolecules into ordered assemblies with the ability to carry out more complex and ambitious cell-like *** activities can provide insights into fundamental cell processes in simplified and idealized systems but could also have an applied impact in synthetic.biology and biotechnology in the *** date,strategies for the bottom-up fabrication of micrometer scale life-like artificial cells have included stabilized water-in-oil droplets,giant unilamellar vesicles(GUV’s),hydrogels,and complex ***-in-oil droplets are a valuable and easy to produce model system for studying cell-like processes;however,the lack of a crowded interior can limit these artificial cells in mimicking life more *** membrane stabilized vesicles,such as GUV’s,have the additional membrane feature of cells but still lack a macromolecularly crowded ***-based artificial cells have a macromolecularly dense interior(although cross-linked)that better mimics cells,in addition to mechanical properties more similar to the viscoelasticity seen in cells but could be seen as being not dynamic in nature and limi

关键词： interior stabilized simplified

Particle shape characterisation and its application to discrete element modelling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2014年第1期12卷 80-89页

作者： Kenneth c.Williams Wei chen sebastian Weeger Timothy J.Donohue centre for bulk Solids and Particulate Technologies Newcastle Institute for Energy and Resources The University of Newcastle Georg-Simon-Ohm University Nuremberg TUNRA bulk Solids Newcastle Institute for Energy and Resources The University of Newcastle

Increasing importance has been placed on particle shape implementation within discrete element mod elling （DEM） in order to more accurately reflect the nonspherical behaviour of the bulk material being handled. As computational resources grow, complex particle shapes are increasingly being modelled as the associated simulation times become more realistic to provide timely solutions. The objective of this research is to assess particle shape descriptors through a digital image segmentation technique, and to further implement particle shape parameters into generation of corresponding irregular shaped DEM particles. Separated and lumped particle images were analysed and reconstructed through the devel opment of two distinct methodologies. Subsequently, various particle shape descriptors were obtained using combinations of image segmentation algorithms, including mathematical morphology processing, thresholding, edge detection, region growing, region splitting and region merging. DEM particles were subsequently created using particle shape results obtained above. Shape parameters of DEM particles were then examined and validated against the real particle shape parameters.

关键词： Particle shapesParticle morphologyImage segmentationDiscrete element modelling

Use of machine learning algorithms to assess the state of roc.burst hazard in underground coal mine openings

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2022年第3期14卷 703-713页

作者： Lukasz Wojtecki sebastian Iwaszenko Derek b.Apel Mirosawa bukowska Janusz Makówka central Mining Institute Katowice40-166Poland School of Mining and Petroleum Engineering University of AlbertaEdmontonT6G 2R3Canada

The risk of roc.bursts is one of the main threats in hard coal mines. compared to other underground mines, the number of factors contributing to the roc.burst at underground coal mines is much *** such as the coal seam tendency to roc.bursts, the thickness of the coal seam, and the stress level in the seam have to be considered, but also the entire coal seam-surrounding rock system has to be evaluated when trying to predict the roc.bursts. However, in hard coal mines, there are stroke or stress-stroke roc.bursts in which the fracture of a thick layer of sandstone plays an essential role in predicting roc.bursts. The occurrence of roc.bursts in coal mines is complex, and their prediction is even more difficult than in other mines. In recent years, the interest in machine learning algorithms for solving complex nonlinear problems has increased, which also applies to geosciences. This study attempts to use machine learning algorithms, i.e. neural network, decision tree, random forest, gradient boosting, and extreme gradient boosting(XGb), to assess the roc.burst hazard of an active hard coal mine in the Upper Silesian coal basin. The rock mass bursting tendency index WTGthat describes the tendency of the seam-surrounding rock system to roc.bursts and the anomaly of the vertical stress component were applied for this purpose. Especially, the decision tree and neural network models were proved to be effective in correctly distinguishing roc.bursts from tremors, after which the excavation was not damaged. On average, these models correctly classified about 80% of the roc.bursts in the testing datasets.

关键词： Hard coal mining Roc.burst hazard Machine learning algorithms

The German Energiewende and its roll-out of renewableenergies： An economic perspective

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2017年第2期11卷 126-134页

作者： sebastian KREUZ Felix MUSGENS Faculty of Mechanical Engineering Electrical and Energy SystemsBrandenburg University of Technology 03046 Cottbus Germany

This paper gives a short overview of the German Energiewende, i.e. the transition of a large and mostly thermal electricity system towards electricity generation from renewable energy source. It discusses both, the motivation of the transitions as future goals and current status. Furthermore, it gives an in-depth view into the changes in economic costs for society as well as electricity price effects, especially for average private households and industrial consumers. It also discusses the benefits of the promotion of renewable energies in Germany.

关键词： electricity system renewable energy cost-benefit analysis

Influence of Non-Uniform Temperature Distribution on Metallic charge Length on Energy and Force Parameters During Groove-Rolling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第8期19卷 17-24页

作者： Mróz sebastian czestochowa University of Technology

change in the temperature of band over its length, associated with the stock being non-uniformly heated in the furnace, influences the variations in the magnitudes of energy-force parameters. Using the FEM (Finite Element Model) programs for the computation of the values of the energy-force parameters can take into account the distribution of temperature over the band length. The mathematical model of the computer program Forge2008 was used to theoretically examine the energy-force parameters and plastic metal flow in the roughing stands of the continuous rolling mill. The results of experimental investigation of influence of the non-uniform temperature distribution were presented on the metallic charge length on the energy and force parameters and dimensions of the band during round bars rolling. Thermovision monitoring energy and force parameters monitoring were carried out in continuous rolling mill D350 in one of the Polish industrial plants. On the basis of obtained results, it could be stated that non-uniform distribution of temperatures along the charge length causes local increase of energy and force parameters values and also such distribution affects the local increase of the width of rolled band. The rolling process of charge with non-uniform distribution of temperature could lead to exceeding required dimensional tolerances of the final products.

关键词： groove-rolling energy parameter force parameter numerical technique FEM

Ab initio density response and local field factor of warm dense hydrogen

在线全文

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2024年第5期9卷 48-67页

作者： Tobias Dornheim sebastian Schwalbe Panagiotis Tolias Maximilian P.böhme Zhandos A.Moldabekov Jan Vorberger center for Advanced Systems Understanding(cASUS) D-02826 GörlitzGermany Helmholtz-Zentrum Dresden-Rossendorf(HZDR) D-01328 DresdenGermany Space and Plasma Physics Royal Institute of Technology(KTH)Stockholm SE-10044Sweden Technische Universität Dresden D-01062 DresdenGermany

We present quasi-exact ab initio path integral Monte carlo(PIMc)results for the partial static density responses and local field factors of hydrogen in the warm dense matter regime,from solid density conditions to the strongly compressed *** full dynamic treatment of electrons and protons on the same footing allows us to rigorously quantify both electronic and ionic exchange–correlation effects in the system,and to compare the results with those of earlier incomplete models such as the archetypal uniform electron gas or electrons in a fixed ion snapshot potential that do not take into account the interplay between the two *** full electronic density response is highly sensitive to electronic localization around the ions,and our results constitute unambiguous predictions for upcoming X-ray Thomson scattering experiments with hydrogen jets and fusion *** PIMc results are made freely available and can be used directly for a gamut of applications,including inertial confinement fusion calculations and the modeling of dense astrophysical ***,they constitute invaluable benchmark data for approximate but computationally less demanding approaches such as density functional theory or PIMc within the fixed-node approximation.

关键词： local incomplete rigorous