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High temperature deformation and recrystallization behavior of magnesium bicrystals with 90°<1010>and 90°<1120>tilt grain boundaries

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Journal of Magnesium and Alloys 2024年第2期12卷 625-638页

作者： kevin Bissa Talal Al-Samman Dmitri A.Molodov Institute of Physical Metallurgy and Materials Physics RWTH Aachen University52056 AachenGermany International Research Organization for Advanced Science and Technology(IROAST) Kumamoto UniversityKumamoto 860-8555Japan

The deformation mechanisms and dynamic recrystallization(DRX)behavior of specifically grown bicrystals with a symmetric 90°and 90°tilt grain boundary,respectively,were investigated under deformation in plane strain compression at 200℃and 400℃.The microstructures were analyzed by panoramic optical microscopy and large-area electron backscatter diffraction(EBSD)orientation mapping.The analysis employed a meticulous approach utilizing hundreds of individual,small EBSD maps with a small step size that were stitched together to provide comprehensive access to orientation and misorientation data on a macroscopic scale.Basal slip primarily governed the early stages of deformation at the two temperatures,and the resulting shear induced lattice rotation around the transverse direction(TD)of the sample.The existence of the grain boundary gave rise to dislocation pile-up in its vicinity,leading to much larger TD-lattice rotations within the boundary region compared to the bulk.With increasing temperature,the deformation was generally more uniform towards the bulk due to enhanced dislocation mobility and more uniform stress distribution.Dynamic recrystallization at 200℃was initiated in{1011}-compression twins at strains of 40%and higher.At 400℃,DRX consumed the entire grain boundary region and gradually replaced the deformed microstructure with progressing deformation.The recrystallized grains displayed characteristic orientations,such that their c-axes were perpendicular to the TD and additionally scattered between 0°and 60°from the loading axis.These recrystallized grains displayed mutual rotations of up to 30°around the c-axes of the initial grains,forming a discernible basal fiber texture component,prominently visible in the{1120}pole figure.It is noteworthy that the deformation and DRX behaviors of the two analyzed bicrystals exhibited marginal variations in response to strain and deformation temperature.

关键词： Elevated deformation temperatures Plain strain compression Magnesium bicrystals Panorama EBSD Dynamic Recrystallization

Genetic analyses of ancient tea trees provide insights into the breeding history and dissemination of chinese Assam tea(camellia sinensis var.assamica)

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Plant Diversity 2024年第2期46卷 229-237页

作者： Miao-Miao Li Muditha K.Meegahakumbura Moses c.Wambulwa kevin S.Burgess Michael Möller Zong-Fang Shen De-Zhu Li Lian-Ming Gao cAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of ScienceKunming650201China Germplasm Bank of Wild Species Kunming Institute of BotanyChinese Academy of ScienceKunming650201China Kunming college of Life Science University of Chinese Academy of SciencesKunming650201YunnanChina Department of Export Agriculture Faculty of Animal Science and Export AgricultureUva Wellassa UniversityBadulla90000Sri Lanka Department of Life Sciences School of Science and ComputingSouth Eastern Kenya University170-90200KituiKenya Department of Biology Columbus State UniversityUniversity System of GeorgiaColumbusGA31907-5645USA Royal Botanic Garden Edinburgh 20A Inverleith RowEdinburghEH35LRScotlandUK Lijiang Forest Biodiversity National Observation and Research Station Kunming Institute of BotanyChinese Academy of SciencesLijiang674100YunnanChina

chinese Assam tea(camellia sinensis var.assamica)is an important tea crop with a long history of cultivation in Yunnan,china.Despite its potential value as a genetic resource,its genetic diversity and domestication/breeding history remain unclear.To address this issue,we genotyped 469 ancient tea plant trees representing 26 c.sinensis var.assamica populations,plus two of its wild relatives(six and three populations of c.taliensis and c.crassicolumna,respectively)using 16 nuclear microsatellite loci.Results showed that chinese Assam tea has a relatively high,but comparatively lower gene diversity(H_(S)=0.638)than the wild relative c.crassicolumna(H_S=0.658).clustering in STRUcTURE indicated that chinese Assam tea and its two wild relatives formed distinct genetic groups,with considerable interspecific introgression.The chinese Assam tea accessions clustered into three gene pools,corresponding well with their geographic distribution.However,New Hybrids analysis indicated that 68.48%of ancient chinese Assam tea plants from Xishuangbanna were genetic intermediates between the Puer and Lincang gene pools.In addition,10%of the ancient chinese Assam tea individuals were found to be hybrids between chinese Assam tea and c.taliensis.Our results suggest that chinese Assam tea was domesticated separately in three gene pools(Puer,Lincang and Xishuangbanna)in the Mekong River valley and that the hybrids were subsequently selected during the domestication process.Although the domestication history of chinese Assam tea in southwestern Yunnan remains complex,our results will help to identify valuable genetic resources that may be useful in future tea breeding programs.

关键词： Tea plant Hybrid origin Genetic diversity Domestication history camellia sinensis var.assamica camellia taliensis

An unsupervised learning approach to study synchroneity of past events in the South china Sea

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Frontiers of Earth Science 2019年第3期13卷 628-640页

作者： kevin c. tse Hon-chim chiu Man-Yin Tsang Yiliang Li Edmund Y. Lam Department of Earth Sciences The University of Hong KongPokfulamHong KongChina Department of Geography and centre for Geo-computation Studies Hong Kong Baptist UniversityKowloon TongHong KongChina Department of Earth Sciences University of TorontoCanada Department of Electrical and Electronic Engineering The University of Hong KongPokfulamHong KongChina

Unsupervised machine learning methods were applied on multivariate geophysical and geochemical datasets of ocean floor sediment cores collected from the South china Sea. The well-preserved and continuous core samples comprising high resolution cenozoic sediment records enable scientists to carry out paleoenvironment studies in detail. Bayesian age-depth chronological models constructed from biostratigraphic control points for the drilling sites are applied on cluster boundaries generated from two popular unsupervised learning methods: K-means and random forest. The unsupervised learning methods experimented have produced compact and unambiguous clusters from the datasets, indicating that previously unknown data patterns can be revealed when all variables from the datasets are taken into account simultaneously. A study of synchroneity of past events represented by the cluster boundaries across geographically separated ocean drilling sites is achieved through converting the fixed depths of cluster boundaries into chronological ranges represented by Gaussian density plots which are then compared with known past events in the region. A Gaussian density peak at around 7.2 Ma has been identified from results of all three sites and it is suggested to coincide with the initiation of the East Asian monsoon. contrary to traditional statistical approach, a priori assumptions are not required for unsupervised learning, and the clustering results serve as a novel data-driven proxy for studying the complex and dynamic processes of the paleoenvironment surrounding the ocean sediment. This work serves as a pioneering approach to extract valuable information of regional events and opens up a systematic and objective way to study the vast global ocean sediment datasets.

关键词： machine learning ocean sediments unsupervised classification

Tensorial tomographic Fourier ptychography with applications to muscle tissue imaging

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Advanced Photonics 2024年第2期6卷 50-60页

作者： Shiqi Xu Xi Yang Paul Ritter Xiang Dai Kyung chul Lee Lucas Kreiss kevin c.Zhou Kanghyun Kim Amey chaware Jadee Neff carolyn Glass Seung Ah Lee Oliver Friedrich Roarke Horstmeyer Duke University DurhamNorth CarolinaUnited States Friedrich-Alexander University ErlangenGermany Uc San Diego La JollaCaliforniaUnited States Yonsei University SeoulRepublic of Korea Uc Berkeley BerkeleyCaliforniaUnited States Duke University Medical center DurhamNorth CarolinaUnited States

We report tensorial tomographic Fourier ptychography(T^(2)oFu),a nonscanning label-free tomographic microscopy method for simultaneous imaging of quantitative phase and anisotropic specimen information in 3D.Built upon Fourier ptychography,a quantitative phase imaging technique,T^(2)oFu additionally highlights the vectorial nature of light.The imaging setup consists of a standard microscope equipped with an LED matrix,a polarization generator,and a polarization-sensitive camera.Permittivity tensors of anisotropic samples are computationally recovered from polarized intensity measurements across three dimensions.We demonstrate T^(2)oFu’s efficiency through volumetric reconstructions of refractive index,birefringence,and orientation for various validation samples,as well as tissue samples from muscle fibers and diseased heart tissue.Our reconstructions of healthy muscle fibers reveal their 3D fine-filament structures with consistent orientations.Additionally,we demonstrate reconstructions of a heart tissue sample that carries important polarization information for detecting cardiac amyloidosis.

关键词： computational imaging three-dimensional imaging phase retrieval microscopy polarization-sensitive imaging labelfree imaging

Potential transformation of organic matter by microbes in cryoconite,Tibetan Plateau

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Science china Earth Sciences 2024年第6期67卷 1978-1989页

作者： Bixi GUO Yongqin LIU kevin Xu ZHONG Quan SHI chen HE Qiang ZHENG Ruanhong cAI State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China center for the Pan-Third Pole Environment Lanzhou UniversityLanzhou 730000China Department of Earth Oceanand Atmospheric SciencesUniversity of British ColumbiaVancouverBC V6T 1Z4Canada State Key Laboratory of Heavy Oil Processing Petroleum Molecules Engineering Center(PMEC)China University of PetroleumBeijing 102249China State Key Laboratory for Marine Environmental Science Collage of Ocean and Earth SciencesXiamen UniversityXiamen 361102China Fujian Key Laboratory of Marine carbon Sequestration Xiamen UniversityXiamen 361005China

Microorganisms play an essential role in the glacier carbon cycle;how they transform organic matter in mountain glacial cryoconite remains to be studied.Here,we applied ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry(FT-IcR MS)and deep sequencing of 16S rRNA gene,to investigate the temporal microbial transformation of dissolved organic matter(DOM)of the Tibetan Plateau cryoconite.During the 60-day incubation,we found that DOM in cryoconite underwent a three-stage transformation,with decreasing bioavailability over time.The microbial community did not change much in the first week while degrading DOM molecules that were associated with higher H/c_(wa)and lower O/c_(wa).During days 15-30,DOM composition remained stable while microbial diversity increased.By day 60,the DOM was microbially converted into a higher state of recalcitrance,with higher values of aromatic index,O/c_(wa),and lower H/c_(wa),which contained molecules containing more heteroatoms.cooperation among various microbial taxa,like cyanobacteria,Bacteroidota,Gammaproteobacteria,Firmicutes,and Actinobacteriota,drove the DOM transformation in cryoconite.This study sheds light on the in-situ transformation of DOM composition meditated by microbial populations in cryoconite at a temporal scale,providing new insights into understanding the microbial roles in the glacier organic carbon transformation.

关键词： cryoconite Dissolved organic matter Biodegradation Microbial community Temporal variation

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

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Genes & Diseases 2024年第3期11卷 155-187页

作者： Michael Yu kevin Qin Jiaming Fan Guozhi Zhao Piao Zhao Wei Zeng connie chen Annie Wang Yonghui Wang jiamin Zhong Yi Zhu William Wagstaff Rex c.Haydon Hue H.Luu Sherwin Ho Michael J.Lee Jason Strelzow Russell R.Reid Tong-chuan He School of Medicine Rosalind Franklin University of Medicine and ScienceNorth ChicagoIL 60064USA Molecular Oncology Laboratory Department of Orthopedic Surgery and Rehabilitation MedicineThe University of Chicago Medical CenterChicagoIL 60637USA Ministry of Education Key Laboratory of Diagnostic Medicine and Department of Clinical BiochemistryThe School of Laboratory MedicineChongqing Medical UniversityChongqing 400016China Department of Orthopedic Surgery The First Affliated Hospital of Chongqing Medical UniversityChongqing 400016China Department of Urology The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016China Department of clinical Laboratory Medicine Shanghai Jiaotong University School of MedicineShanghai 200000China Department of Orthopaedic Surgery Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100730China Laboratory of craniofacial Suture Biology and Development Department of Surgery Section of Plastic SurgeryThe University of Chicago Medical CenterChicagoIL 60637USA Department of Neurology The First Dongguan Affiliated HospitalGuangdong Medical UniversityDongguanGuangdong 523475China

The evolutionarily conserved Wnt signaling pathway plays a central role in develop-ment and adult tissue homeostasis across species.Wnt proteins are secreted,lipid-modified signaling molecules that activate the canonical(β-catenin dependent)and non-canonical(β-catenin independent)Wnt signaling pathways.cellular behaviors such as proliferation,differ-entiation,maturation,and proper body-axis specification are carried out by the canonical pathway,which is the best characterized of the known Wnt signaling paths.Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues.This includes but is not limited to embryonic,hematopoietic,mesenchymal,gut,neural,and epidermal stem cells.Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties.Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders.Not surprisingly,aberrant Wnt signaling is also associated with a wide variety of diseases,including cancer.Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation,epithelial-mesenchymal transition,and metastasis.Altogether,advances in the understand-ing of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway.Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt,this review aims to summarize the cur-rent knowledge of Wnt signaling in stem cells,aberrations to the Wnt pathway associated with diseases,and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

关键词： β-catenin cancer canonical Wnt Disease Non-canonical Wnt Stem cells Targeted therapy Wnt signaling

canonical and noncanonical Wnt signaling: Multilayered mediators, signaling mechanisms and major signaling crosstalk

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Genes & Diseases 2024年第1期11卷 103-134页

作者： kevin Qin Michael Yu Jiaming Fan Hongwei Wang Piao Zhao Guozhi Zhaoo Wei Zeng connie chen Yonghui Wang Annie Wang Zander Schwartz Jeffrey Hong Lily Song William Wagstaff Rex c.Haydon Hue H.Luu Sherwin H.Ho Jason Strelzow Russell R.Reid Tong-chuan He Lewis L.Shi chicago Medical School Rosalind Franklin University of Medicine and ScienceNorth ChicagoIL 60064USA Molecular Oncology Laboratory Department of Orthopaedic Surgery and Rehabilitation MedicineThe University of Chicago Medical CenterChicagoIL 60637USA Ministry of Education Key Laboratory of Diagnostic Medicine and Department of Clinical BiochemistryThe School of Laboratory MedicineChongqing Medical UniversityChongqing 400016China Departments of Orthopaedic Surgery and Urology The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016China Department of Interventional Neurology The First Dongguan Affiliated HospitalGuangdong Medical UniversityDongguanGuangdong 523475China Department of clinical Laboratory Medicine Shanghai Jiaotong University School of MedicineShanghai 200000China School of Biomedical Engineering Vanderbilt UniversityNashvilleTN 37235USA Laboratory of craniofacial Biology and Development Department of Surgery Section of Plastic SurgeryThe University of Chicago Medical CenterChicagoIL 60637USA

Wnt signaling plays a major role in regulating cell proliferation and differentiation.The Wnt ligands are a family of 19 secreted glycoproteins that mediate their signaling effects via binding to Frizzled receptors and LRP5/6 coreceptors and transducing the signal either throughβ-catenin in the canonical pathway or through a series of other proteins in the nonca-nonical pathway.Many of the individual components of both canonical and noncanonical Wnt signaling have additional functions throughout the body,establishing the complex interplay between Wnt signaling and other signaling pathways.This crosstalk between Wnt signaling and other pathways gives Wnt signaling a vital role in many cellular and organ processes.Dys-regulation of this system has been implicated in many diseases affecting a wide array of organ systems,including cancer and embryological defects,and can even cause embryonic lethality.The complexity of this system and its interacting proteins have made Wnt signaling a target for many therapeutic treatments.However,both stimulatory and inhibitory treatments come with potential risks that need to be addressed.This review synthesized much of the current knowl-edge on the Wnt signaling pathway,beginning with the history of Wnt signaling.It thoroughly described the different variants of Wnt signaling,including canonical,noncanonical Wnt/PcP,and the noncanonical Wnt/ca2+pathway.Further description involved each of its components and their involvement in other cellular processes.Finally,this review explained the various other pathways and processes that crosstalk with Wnt signaling.

关键词： β-catenin canonical Wnt Noncanonical Wnt Signal transduction Signaling crosstalk

Multinuclear MR and MRI study of lithium-ion cells using a variable field magnet and a fixed frequency RF probe

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Magnetic Resonance Letters 2024年第1期4卷 10-20页

作者： Andrés Ramírez Aguilera Florin Marica kevin J.Sanders Md Al Raihan c.Adam Dyker Gillian R.Goward Bruce *** UNB MRI centre Department of PhysicsUniversity of New BrunswickFrederictonNew BrunswickE3B 5A3Canada Department of chemistry McMaster UniversityHamiltonOntarioL8S 4L8Canada Department of chemistry University of New BrunswickFrederictonNew BrunswickE3B 5A3Canada

An exploratory multinuclear magnetic resonance(MR)and magnetic resonance imaging(MRI)study was performed on lithium-ion battery cells with ^(7)Li,^(19)F,and ^(1)H measurements.A variable field superconducting magnet with a fixed frequency parallel-plate radiofrequency(RF)probe was employed in the study.The magnetic field was changed to set the resonance frequency of each nucleus to the fixed RF probe frequency of 33.7 MHz.Two cartridge-like lithium-ion cells,with graphite anodes and LiNi_(0.5)Mn_(0.3)co_(0.2)O_(2)(NMc)cathodes,were interrogated.One cell was pristine,and one was charged to a cell voltage of 4.2 V.The results presented demonstrate the great potential of the variable field magnet approach in multinuclear measurement of lithium-ion batteries.These methods open the door for developing faster and simpler methods for detecting,quantifying,and interpreting MR and MRI data from lithium-ion and other batteries.

关键词： Multinuclear MR/MRI Variable field magnet Lithium-ion battery Parallel-plate rf probe

Interfacial engineering through lead binding using crown ethers in perovskite solar cells

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Journal of Energy chemistry 2024年第5期92卷 263-270页

作者： Sun-Ju Kim YeonJu Kim Ramesh Kumar chitumalla Gayoung Ham Thanh-Danh Nguyen Joonkyung Jang Hyojung cha Jovana Milić Jun-Ho Yum kevin Sivula Ji-Youn Seo Department of Nano Fusion Technology Pusan National UniversityBusan 46241Republic of Korea Laboratory for Molecular Engineering of Optoelectronic Nanomaterials Institute of Chemical Sciences and EngineeringÉcole Polytechnique Fédérale de Lausanne(EPFL)1015 LausanneSwitzerland Department of Energy convergence and climate change Kyungpook National UniversityDaegu 41566Republic of Korea Department of Hydrogen and Renewable Energy Kyungpook National UniversityDaegu 41566Republic of Korea Adolphe Merkle Institute University of FribourgCH-1700 FribourgSwitzerland

In the domain of perovskite solar cells(PScs),the imperative to reconcile impressive photovoltaic performance with lead-related issue and environmental stability has driven innovative solutions.This study pioneers an approach that not only rectifies lead leakage but also places paramount importance on the attainment of rigorous interfacial passivation.crown ethers,notably benzo-18-crown-6-ether(B18c6),were strategically integrated at the perovskite-hole transport material interface.crown ethers exhibit a dual role:efficiently sequestering and immobilizing Pb^(2+)ions through host-guest complexation and simultaneously establishing a robust interfacial passivation layer.Selected crown ether candidates,guided by density functional theory(DFT)calculations,demonstrated proficiency in binding Pb2+ions and optimizing interfacial energetics.Photovoltaic devices incorporating these materials achieved exceptional power conversion efficiency(PcE),notably 21.7%for B18c6,underscoring their efficacy in lead binding and interfacial passivation.Analytical techniques,including time-of-flight secondary ion mass spectrometry(ToF-SIMS),ultraviolet photoelectron spectroscopy(UPS),time-resolved photoluminescence(TRPL),and transient absorption spectroscopy(TAS),unequivocally affirmed Pb^(2+)ion capture and suppression of non-radiative recombination.Notably,these PScs maintained efficiency even after enduring 300 h of exposure to 85%relative humidity.This research underscores the transformative potential of crown ethers,simultaneously addressing lead binding and stringent interfacial passivation for sustainable PScs poised to commercialize and advance renewable energy applications.

关键词： Perovskite solar cells Interfacial passivation crown ether materials Stability