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Bistability theorem in a cancer model

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International Journal of Biomathematics 2018年第1期11卷 61-98页

作者： jens christian Larsen Vanlcse Alle 50 2. mr. tv2720 VanlCse Copenhagen Denmark

In this paper, I continue the study of the mathematical models presented in [J. C. Larsen, Models of cancer growth, J. Appl. Math. Comput. 53（1-2）（2015） 613-645] and [J. C. Larsen, The bistability theorem in a model of metastatic cancer, to appear in Appl. Math.]. I shall prove the bistability theorem for the ODE model from [Larsen, 2015]. It is a mass action kinetic system in the variables C cancer, GF growth factor and GI growth inhibitor. This theorem says that for some values of the parameters, there exist two positive singular points c＊＋ = （C＊＋, GF＊., GI＊＋）, c＊2- = （C＊-, GF＊, GI＊-） of the vector field. Here C＊- 〈 C＊＋ and e. is stable and c＊＋ is unstable, see Sec. 2. There is also a discrete model in [Larsen, 2015], it is a linear map （T） on three-dimensional Euclidean vector space with variables （C, GF, GI）, where these variables have the same meaning as in the ODE model above. In [Larsen, 2015], I showed that one can sometimes find attine vector fields on three-dimensional Euclidean vector space whose time one map is T. I shall also show this in the present paper in a more general setting than in [Larsen, 2015]. This enables me to find an expression for the rate of change of cancer growth on the coordinate hyperplane C = 0 in Euclidean vector space. I also present an ODE model of cancer metastasis with variables C, CM, CF,GI, where C is primary cancer and CM is metastatic cancer and GF, GI are growth factors and growth inhibitors, respectively.

关键词： Immunology cancer chemotherapy immune therapy discrete dynamicalsystem Gompertz function.

Is serine racemase(SRR) a second hit target for LRRK2-G2019S induced Parkinson's disease?

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Neural Regeneration Research 2021年第3期16卷 498-499页

作者： Sarah Louise Nickels jens christian Schwamborn Luxembourg Centre for Systems Biomedicine(LCSB) University of LuxembourgBelvauxLuxembourg Riken Institute for Medical Sciences(IMS) KanagawaJapan

To date,at least 7 million people are suffering from Parkinson's disease(PD)worldwide,which is the second most prevalent,age-associated,and progressive neurodegenerative disorder(Tysnes and Storstein,2017).Given the accelerated global pace of aging,it becomes of fundamental importance that we start understanding the origins of neurodegeneration in order to develop effective disease modifying *** PD patients suffer from a combination of motor and nonmotor disabilities.

关键词： second patients suffering

Melt flow,heat transfer and solidification in a flexible thin slab continuous casting mold with vertical-combined electromagnetic braking

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Journal of Iron and Steel Research International 2024年第2期31卷 401-415页

作者： Lin Xu Ze-feng Han christian Karcher en-gang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang110819LiaoningChina Key Laboratory of Liaoning Province for Clean Combustion Power Generation and Heating Technology Shenyang Institute of EngineeringShenyang110136LiaoningChina Institute of Thermodynamics and Fluid Mechanics Technische Universität IlmenauIlmenau98684Germany

During continuous casting of steel slabs,the application of electromagnetic braking technology(EMBr)provides an effective tool to influence solidification by controlling the pattern of melt flow in the ***,the quality of the final product can be improved considerably.A new electromagnetic braking(EMBr)method,named vertical-combined electromagnetic braking(VC-EMBr),is proposed to be applied to a flexible thin slab casting(FTSC)*** evaluate the beneficial effects of the VC-EMBr,the melt flow,heat transfer,and solidification processes in the FTSC mold are studied by means of numerical *** detail,a Reynolds-averaged Navier–Stokes turbulence model together with an enthalpy-porosity approach was *** numerical findings are compared with respective simulations using the traditional *** results demonstrate that the application of the VC-EMBr contributes significantly to preventing relative slab *** contrast to the Ruler-EMBr,the additional vertical magnetic poles of the VC-EMBr preferentially suppress the direct impact of jet flow on the narrow face of FSTC mold and considerably diminish the level fluctuation near the meniscus *** instance,by applying a magnetic flux density of 0.3 T,the maximum amplitude of meniscus deflection reduces by about 80%.Moreover,the braking effect of the VC-EMBr effectively improves the homogeneity of temperature distribution in the upper recirculation region and increases the solidified shell thickness along the casting *** this basis,the newly proposed VC-EMBr shows a beneficial effect in preventing relative slab defects for FTSC thin slab continuous casting.

关键词： Electromagnetic braking Mold Melt flow Heat transfer Solidification

A concurrent optimization approach for energy efficient multiple axis positioning tasks

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Journal of Control and Decision 2016年第4期3卷 223-247页

作者： christian Hansen jens Kotlarski Tobias Ortmaier Institute of Mechatronic Systems Leibniz Universitat HannoverHanoverGermany

Automated production systems typically comprise numerous electrical servo drives,many of which conduct positioning motions,*** handling or manipulation *** power electronics of modern multi-axis systems often comprise coupled DC-links,enabling for internal exchange of recuperative brake ***,the motion sequences of manipulators are often commanded at maximum dynamics for minimum time motion,neglecting possible optimization potential,*** idle time,leading to inefficient energy management.A robust trajectory optimization approach based on the particle swarm algorithm and well-established path planning methods is presented for the adaption of multi-axis positioning tasks with only two parameters per axis and positioning motion during system *** results prove that,depending on the positioning task and chosen optimization constraints,energy demands are distinctly *** approach is applicable to diverse multi-axis configurations and enables for considerable energy savings without additional hardware invest.

关键词： Multiple axis systems electrical servo drive energy efficient control trajectory optimization positioning tasks

Ethyl-iophenoxic acid as a quantitative bait marker for small mammals

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Integrative Zoology 2022年第6期17卷 981-990页

作者： Kyra JACOBLINNERT christian IMHOLT Detlef SCHenKE jens JACOB Julius Kühn Institute(JKI) Federal Research Centre for Cultivated PlantsInstitute for Plant Protection in Horticulture and ForestsVertebrate ResearchMünsterGermany Department of Behavioral Biology University of OsnabrückOsnabrückGermany Julius Kühn Institute(JKI) Federal Research Centre for Cultivated PlantsInstitute for Ecological ChemistryPlant Analysis and Stored Product ProtectionBerlinGermany

Bait markers are indispensable for ecological research but in small mammals,most markers are invasive,expensive and do not enable quantitative analyses of ***-iophenoxic acid(Et-IPA)is a non-toxic,quantitative bait marker,which has been used for studying bait uptake in several carnivores and *** developed a bait with Et-IPA,assessed its palatability to common voles(Microtus arvalis),and determined the dose-residue-relation for this important agricultural pest rodent ***-IPA concentrations of 40 to 1280μg Et-IPA per g bait were applied to wheat using sunﬂower oil or polyethylene glycol 300 as potential *** a laboratory study,common voles were offered the bait and blood samples were collected 1,7,and 14 days after *** samples were analyzed with LC-ESI-MS/MS for blood residues of ***ﬂower-oil was the most suitable bait ***-IPA seemed to be palatable to common voles at all test ***-dependent residues could be detected in blood samples in a dose-dependent manner and up to 14 days after uptake enabling generation of a calibration curve of the dose-residue ***-IPA was present in common vole blood for at least 14 days,but there was dissipation by 33–37%depending on ***-IPA meets many criteria for an“ideal”quantitative bait marker for use in futureﬁeld studies on common voles and possibly other small mammal species.

关键词： baiting biomarker Microtus arvalis quantitative bait marker small mammals

Wear dependent virtual flow rate sensor for progressing cavity pumps with deformable stator

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Petroleum Science 2024年第2期21卷 1346-1353页

作者： jens Müller Sebastian Leonow Johannes Schulz christian Hansen Martin Monnigmann Ruhr-Universitat Bochum Universit atsstraûe 150Bochum44801Germany SEEPEX GmbH Scharnh olzstraûe 344Bottrop46240Germany

This contribution presents a novel wear dependent virtual flow rate sensor for single stage single lobe progressing cavity pumps. We study the wear-induced material loss of the pump components and the impact of this material loss on the volumetric efficiency. The results are combined with an established backflow model to implement a backflow calculation procedure that is adaptive to wear. We use a laboratory test setup with a highly abrasive fluid and operate a pump from new to worn condition to validate our approach. The obtained measurement data show that the presented virtual sensor is capable of calculating the flow rate of a pump being subject to wear during its regular operation.

关键词： Backflow Progressing cavity pump Virtual sensor Wear

Like or dislike:Response of rodents to the odor of plant secondary metabolites

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Integrative Zoology 2017年第5期12卷 428-436页

作者： Sabine C.HANSen Caroline STOLTER christian IMHOLT jens JACOB Julius-Kühn Institute for Plant Protection in Horticulture and Forests Vertebrate ResearchMünsterGermany University Hamburg Biocenter Grindel and Zoological MuseumHamburgGermany

Rodents,including common voles(Microtus arvalis)and house mice(Mus musculus)cause immense pre-harvest and post-harvest ***,developing methods that mitigate these losses while maintaining their role in ecosystems is a *** plant secondary metabolites(PSM)which significantly reduce food intake of both species under laboratory conditions have been ***,before these can be used in rodent pest management,they must be tested under more natural conditions where other food sources are *** this study,the odors of 4 PSMs were evaluated for their repellent effects in experiments conducted in semi-natural *** treated with PSMs or untreated soil(experimental control)was placed in an underground box containing food(rolled oats).We quantified the number of visits to each box and could demonstrate that all 4 PSMs reduced the number of visits to treatment boxes in both rodent *** common voles the combination of methyl nonyl ketone+black pepper oil was the most repellent *** mice made fewer visits to all PSM boxes;boxes with the anthraquinone were visited ***,house mice consumed less food from boxes containing soil treated with all 4 *** results suggest that PSMs are repellent in murid and microtine rodents under semi-field *** addition,the future use of PSM odors for repelling both pest species,especially house mice,seems *** investigations with other PSMs,different concentrations as well as alternative application methods are needed to repel common voles from attractive crops.

关键词： enclosure trials odor plant secondary metabolites repellents rodents

Advanced brain organoids for neuroinflammation disease modeling

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Neural Regeneration Research 2024年第1期19卷 154-155页

作者： Sonia Sabate-Soler Henry Kurniawan jens christian Schwamborn Luxembourg Centre for Systems Biomedicine University of LuxembourgEsch-sur-AlzetteLuxembourg

Brain organoids mimic closely the embryonic human brain:Over the last decade,the development of human organoid systems has evolved *** tissues have been modeled with organoids,such as the gut,lung,liver,kidney retina and *** systems have a high cellular heterogeneity,with many cell types integrated into the same ***'cellular populations interact between and amongst each other in a cellular and molecular level,which represents an advantage with respects to monolayer 2D cell culture systems.

关键词： inflammation lung kidney

Early dynamics in plant community trait responses to a novel, more extreme hydrological gradient

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Journal of Plant Ecology 2019年第2期12卷 327-335页

作者： Andrea Oddershede Cyrille Violle Annette Baattrup-Pedersen jens-christian Svenning christian Damgaard Section for Plant and Insect Ecology Department of BioscienceAarhus UniversityVejlsøvej 25DK-8600 SilkeborgDenmark Section for Ecoinformatics&Biodiversity Department of BioscienceAarhus UniversityNy Munkegade 114DK-8000 Aarhus CDenmark CEFE UMR 5175 CNRS-Universitéde Montpellier-UniversitéPaul-Valéry MontpellierEPHE-1919 route de MendeF-34293 MontpellierCEDEX 5France Section for Stream and Wetland Ecology Department of BioscienceAarhus UniversityVejlsøvej 25DK-8600 SilkeborgDenmark

Aims For temperate regions such as Northern Europe,predicted climate change patterns include an increase in winter precipitation causing increased risk of flooding,whereas periods of droughts will become more frequent in *** aim of this study is to explore vari-ations in plant functional trait distributions along a hydrological gradient spanning from recurrent drought events to recurrent flood-ing-mimicking future precipitation *** The experiment was conducted in a controlled grassland experi-ment over a period of 3 years.A novel and more extreme hydro-logical regime was achieved by manipulating the flow of a nearby stream thereby creating a continuous hydrological gradient from flooding during winter to drought during *** commu-nity responses were recorded along this hydrological ***-weighted trait distribution changes along the gradient were described using null *** functional traits were con-sidered:seed mass,leaf dry matter content(LDMC),leaf area,leaf thickness,specific leaf area(SLA)and *** findings Over time,responses in plant functional traits changed at the community *** the study period consistent changes occurred in the mean trait value of several *** in relatively dry plots became dominated by species with water-conserving life strategies,represented by high seed mass and thick *** contrast,disturbance-resistant species(high leaf dry matter content)became dominant in flooded plots,indicating that persistence to flooding was the most important factor control-ling the functional structure in those ***,a high abundance of small-seeded species in flooded plots likely indicates higher frequency of species with higher dispersal ability through *** conclusion,plant traits are useful for predicting responses to climate change,but abrupt and extreme climate event may cause unexpected responses because they have no analog to previously more sta

关键词： functional diversity trait-environment relationship hydrology extreme events flooding