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Thermal conductivity suppression in uranium-doped thorium dioxide due to phonon-spin interactions

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Journal of Materiomics 2024年第3期10卷 709-715页

作者： Zilong Hua Saqeeb Adnan Amey R.Khanolkar karl Rickert David b.Turner Timothy A.Prusnick J.Matthew Mann David H.Hurley Marat Khafizov Cody A.Dennett Materials Science and Engineering Department Idaho National LaboratoryIdaho FallsID83415USA Department of Mechanical and Aerospace Engineering The Ohio State UniversityColumbusOH43210USA KbR DaytonOH45431USA Azimuth Corporation FairbornOH45324USA Air Force Research Laboratory Wright-Patterson AFBOH45433USA Department of Nuclear Science and Engineering Massachusetts Institute of TechnologyCambridgeMA02139USA

In this work,impact of low level of uranium(U)atom substitution on thermal conductivity of thorium dioxide(ThO_(2))is ***_(2)is an electronic insulator with a wide optical band-gap and no unpaired electrons whose thermal transport is governed by phonons.U-substitution introduces unpaired f-electrons resulting in paramagnetic behavior of UeThO_(2)at room temperature,which significantly suppresses its thermal conductivity.A single crystal of UeThO_(2)with graded composition of U is grown using a hydrothermal synthesis method,and thermal conductivity measurements are performed in re-gions with uniform composition of U at levels of 0%,6%,9%and 16%.Measured thermal conductivity profiles over 77e300 K temperature range are analyzed using an analytical expression for phonon-mediated thermal transport based on Klemens-Callaway *** dependent thermal con-ductivity is found to deviate significantly from the Rayleigh scattering trend expected for a simple substitutional point defect with a small perturbation to mass and interatomic *** the resonant scattering term,observed large suppression of thermal conductivity at low temperatures can be closely ***,the extracted phonon-spin coupling constants imply a nonlinear relation of phonon-spin interaction intensity with respect to U doping *** study reveals how phonon-spin scattering contributed by unpaired f-electrons in U atoms influences thermal transport in the UeThO_(2)system.

关键词： Phonon-spin interactions Thermal conductivity UdThO_(2)system

Enhanced diagnostic workup increases pathological findings in patients with acute ischaemic stroke:results of the prospective HEbRAS study

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Stroke & Vascular Neurology 2024年第2期9卷 145-152,I0414-I0425页

作者： Simon Hellwig Thomas Krause Jan F Scheitz Juliane Herm Ulrike Grittner Nadja Jauert Jochen b Fiebach Mario Kasner Wolfram Doehner Matthias Endres Rolf Wachter Thomas Elgeti Christian H Nolte karl Georg Haeusler Department of Neurology with Experimental Neurology Charité-Universitätsmedizin Berlincorporate member of Freie Universität Berlin and Humboldt-Universität zu BerlinBerlinGermany Center for Stroke Research berlin BerlinGermany berlin Institute of Health at Charité–Universitätsmedizin berlin BIH Biomedical Innovation AcademyBerlinGermany Department of Neurology Jüdisches Krankenhaus BerlinBerlinGermany German Center for Cardiovascular Diseases(DZHK) Partner Site BerlinBerlinGermany Institute of biometry and Clinical Epidemiology Charité-Universitätsmedizin BerlinBerlinGermany bIH Center for Regenerative Therapies(bCRT) Berlin Institute of Health at Charité–Universitätsmedizin BerlinBerlinGermany Department of Cardiology Charité-Universitätsmedizin BerlinBerlinGermany Department of Cardiology Campus Benjamin FranklinCharité-Universitätsmedizin BerlinBerlinGermany German Center for Neurodegenerative Diseases(DZNE) Partner Site BerlinBerlinGermany Department of Cardiology University Hospital LeipzigLeipzigGermany Department of Radiology Charité-Universitätsmedizin BerlinBerlinGermany Department of Neurology University Hospital WürzburgWürzburgGermany

background Stroke aetiology remains cryptogenic in a relevant proportion of patients with acute ischaemic stroke(AIS).We assessed whether enhanced diagnostic workup after AIS yields a higher rate of prespecified pathological findings compared with routine diagnostic care *** Hospitalised patients with AIS were prospectively enrolled in the investigator-initiated observational HEart and bRain Interfaces in Acute Ischaemic Stroke(HEbRAS)study at the Charité,berlin,*** with AIS without known atrial fibrillation(AF)underwent cardiovascular MR imaging(CMR),MR-angiography of the aortic arch and prolonged Holter-ECG monitoring on top of routine diagnostic *** Among 356 patients with AIS(mean age 66 years,37.6%female),enhanced workup yielded a higher rate of prespecified pathological findings compared with routine care(17.7%vs 5.3%;pber NCT02142413.

关键词： routine patients prospective

Enemies atpeace:Recentprogressin Agrobacterium-mediated cereal transformation

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The Crop Journal 2024年第2期12卷 321-329页

作者： Shaoshuai Liu Ke Wang Shuaifeng Geng Moammar Hossain Xingguo Ye Aili Li Long Mao karl-Heinz Kogel State Key Laboratory of Crop Gene Resources and breeding Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing 100081China Institute of Phytopathology Centre for BioSystemsLand Use and NutritionJustus Liebig UniversityHeinrich Buff-Ring 26-32D-35392GiessenGermany

Agrobacterium tumefaciens mediated plant transformation is a versatile tool for plant genetic engineering following its discovery nearly half a century *** modifications were made in its application to increase efficiency,especially in the recalcitrant major cereals *** breakthroughs in transformation efficiency continue its role as a mainstream technique in CRISPR/Cas-based genome editing and gene *** modifications led to higher transformation frequency and lower but more stable transgene copies with the capability to revolutionize modern *** this review,we provide a brief overview of the history of Agrobacterium-mediated plant transformation and focus on the most recent progress to improve the system in both the Agrobacterium and the host recipient.A promising future for transformation in biotechnology and agriculture is predicted.

关键词： Agrobacterium tumefaciens Cereal species Genome editing Genetic engineering Plant breeding

Diverse experiences by active travel for carbon neutrality:A longitudinal study of residential context,daily travel and experience types

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Geography and Sustainability 2024年第3期5卷 459-469页

作者： karl Samuelsson S.Anders brandt Stephan barthel Noah Linder Nancy Joy Lim David Hallman Matteo Giusti Department of building Engineering Energy Systems and Sustainability ScienceFaculty of Engineering and Sustainable DevelopmentUniversity of Gävle 80176 GävleSweden ISGlobal Barcelona Biomedical Research ParkDoctor Aiguader 8808003 BarcelonaSpain Department of Computer and Geospatial Sciences Faculty of Engineering and Sustainable DevelopmentUniversity of Gävle 80176 GävleSweden Stockholm Resilience Centre Stockholm University 10691 StockholmSweden Global Economic Dynamics and the biosphere Royal Swedish Academy of ScienceLilla Frescativägen 4A 11418 StockholmSweden Department of Occupational Health Science and Psychology Faculty of Health and Occupational StudiesUniversity of Gävle 80176 GävleSweden School of Sustainability Civil and Environmental EngineeringFaculty of Engineering and Physical SciencesUniversity of SurreyGuildfordSurrey GU27XHUK

Two key goals for sustainable spatial planning are to promote low-carbon travel in daily life and to enhance human wellbeing through diverse human-environment ***,the integration of these goals has been *** study investigates the potential for experiential diversity via active travel in different resi-dential contexts within the Gävle city-region,*** 15 months,we collected spatiotemporal data from 165 participants,analyzing 4,362 reported experiences and 13,192 GPS-derived travel *** analysis uncovered a significant spatial discrepancy:while the travelled distances to locations of positive experiences typ-ically ranged from 1.5 km to 5 km,active travel predominated only within 1.5 *** discrepancy persisted across urban,suburban,and peripheral *** residents in different contexts reported the same types of experiences,urban dwellers travelled about 50%farther for nature experiences compared with other positive experiences,whereas peripheral dwellers travelled twice the distance for urbanicity experiences compared with other positive ***,urban residents mostly relied on active travel for urbanicity experiences and motorised travel for nature experiences,with the reverse trend observed among peripheral *** results illustrate the importance of spatial scale for promoting diverse positive experiences via active travel,re-gardless of residential *** planning strategies may include enhancing environmental diversity near homes and developing infrastructure that favours active over motorised travel for short to moderate distances.

关键词： Walking biking Experiential diversity GPS data Smartphone app Topodiversity

Dedicated to Professor Dr.-Ing. ***.h.c. Jurgen Zierep for his 80^(th) birthday Pattern Formation in Rotating Fluids

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Journal of Thermal Science 2009年第2期18卷 109-118页

作者： karl bühler Department of Mechanical and Process Engineering University of Applied Sciences

Flows in nature and technology are often associated with specific structures and pattern. This paper deals with thedevelopment and behaviour of such flow pattern. Flow structures are important for the mass, momentum and energytransport. The behaviour of different flow pattern is used by engineers to obtain an efficient mass and energyconsumption. Mechanical power is transmitted via the momentum of rotating machine parts. Therefore thephysical and mathematical knowledge of these basic concepts is important. Theoretical and experimental investigationsof principle experiments are described in the following. We start with the classical problem of the flowbetween two concentric cylinders where the inner cylinder rotates. Periodic instabilities occur which are calledTaylor vortices. The analogy between the cylindrical gap flow, the heat transfer in a horizontal fluid layer exposedto the gravity field and the boundary layer flow along concave boundaries concerning their stability behaviour isaddressed. The vortex breakdown phenomenon in a cylinder with rotating cover is also described. A generalizationto spherical sectors leads then to investigations with different boundary conditions. The spherical gap flowexhibits interesting phenomena concerning the nonlinear character of the Navier-Stokes equations. Multiple solutionsin the nonlinear regime give rise to different routes during the laminar-turbulent transition. The interactionof two rotating spheres results in flow structures with separation and stagnation lines. Experimental results areconfirmed by numerical simulations.

关键词： Rotating Fluids Stability behaviour bifurcation Vortices Laminar-turbulent Transition

Pattern Formation Around Interacting bodies in Rotating Fluids

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Journal of Thermal Science 2006年第2期15卷 132-134页

作者： karl bHLER University of Applied Sciences badstrasse 24 D-77652 Offenburg Germany

The interaction of bodies like spheres and disks in rotating fluids leads to novel flow structures. The primary swirling flow in circumferential direction is superimposed by a secondary motion in the meridional plane. The flow is visualized by introducing ink through a hole in the center of the axes and distributed radially in the central plane between the interacting bodies. The flow structure depends on the shape of the bodies, their geometrical arrangement and the Reynolds number given by the rotational speed. The observed flow structures gave rise to further investigations with PIV-measurcments and numerical simulations.

关键词： Rotating fluids pattern formation recirculation zones interacting bodies flow visualization

Luteolin， a common flavone in vegetables， acts as a hormetin possessing neurotrophic function: signaling mediated by inducing mitochondrial stress

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Food Science and Human Wellness 2024年

作者： Alex Xiong Gao Tracy Chenxi Xia Maggie Suisui Guo Gary Kawing Yuen Kevin Qiyun Wu Tina Tingxia Dong karl Wah-Keung Tsim Shenzhen Key Laboratory of Edible and Medicinal bioresources， HKUST Shenzhen Research Institute Division of Life Science and Center for Chinese Medicine， The Hong Kong University of Science and Technology

This study aims to uncover the hormetic process of luteolin， a common dietary flavone， in neuronal cells through its role in inducing mitochondrial stress. In rat pheochromocytoma PC12 cells， luteolin at low concentrations caused a mild and reversible loss of mitochondrial membrane potential (MMP)， while high concentrations of luteolin triggered intense and sustained depolarization of MMP. The MMP disturbance was shown to have a close association with the trophic and/or toxic effects triggered by luteolin; because the common mitochondrial uncouplers shared similar bi-phase dose-response on cell viability， as that of luteolin. Along with the induced MMP pertubation， luteolin triggered the development of autophagy and mitophagy， as determined by mCherry-GFP-LC3b tandem protein， and by the co-localization of mitochondrial/lysosomal staining. Subsequent application of autophagy inhibitors in the cultures blocked the luteolin-induced neurotrophic activities and sensitized the cells to be less resistant to luteolin-mediated cytotoxicity. Other flavonoids also displayed similar properties in the cultures， indicating that these compounds act as hormetic pharmacological inducers that stimulate cells to become more resilient and adapt to threats. This study provides a unifying mechanistic explanation for the neuro-beneficial effects of luteolin and other flavonoids.

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An active self-cleaning surface system for photovoltaic modules using anisotropic ratchet conveyors and mechanical vibration

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Microsystems & Nanoengineering 2020年第1期6卷 413-424页

作者： Di Sun karl F.bohringer Department of Electrical and Computer Engineering University of WashingtonSeattleWA 98195USA Institute for Nano-Engineered Systems University of WashingtonSeattleWA 98195USA

The purpose of this work is to develop an active self-cleaning system that removes contaminants from a solar module surface by means of an automatic,water-saving,and labor-free *** output efficiency of a solar module can be degraded over time by dust accumulation on top of the cover glass,which is often referred to as“soiling”.This paper focuses on creating an active self-cleaning surface system using a combination of microsized features and mechanical *** features,which are termed anisotropic ratchet conveyors(ARCs),consist of hydrophilic curved rungs on a hydrophobic *** different ARC systems have been designed and fabricated with self-assembled monolayer(SAM)silane and fluoropolymer thin film(Cytop).Fabrication processes were established to fabricate these two systems,including patterning Cytop without degrading the original Cytop *** droplet transport characteristics,including anisotropic driving force,droplet resonance mode,cleaning mechanisms,and system power consumption,were studied with the help of a high-speed camera and custom-made test *** droplet can be transported on the ARC surface at a speed of 27 mm/s and can clean a variety of dust particles,either water-soluble or *** transmission was measured to show that Cytop can improve transmittance by 2.5~3.5%across the entire visible wavelength ***-time demonstrations of droplet transport and surface cleaning were performed,in which the solar modules achieved a 23 percentage-point gain after cleaning.

关键词： anisotropic cleaning remove

Transporting droplets through surface anisotropy

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Microsystems & Nanoengineering 2015年第1期1卷 74-81页

作者： Hal R.Holmes karl F.böhringer Department of bioengineering University of WashingtonSeattleWA 98195USA Department of Electrical Engineering University of WashingtonSeattleWA 98195USA

This review article examines digital microfluidic systems that manipulate droplets through surface *** systems are categorized as surface tension driven or contact line *** tension driven systems include electrowetting on dielectric,Marangoni flow on microheater arrays,and chemical gradient surfaces,whereas contact line driven systems include anisotropic ratchet conveyors,nanostructured Parylene ratchets,and tilted pillar *** article describes the operating principles and outlines the fabrication procedures for each *** also present new equations that unify several previous models of contact line driven *** strengths and weaknesses of each system are compared,with a focus on their ability to perform the generation,switching,fusion,and fission of ***,we discuss current and potential future applications of these systems.

关键词： droplets digital microfluidics electrowetting thermocapillary forces contact line oscillation