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Cryo-EM structure of a tetrameric photosystem I from Chroococcidiopsis TS-821, a thermophilic, unicellular, non-heterocyst-forming cyanobacterium

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Plant Communications 2022年第1期3卷 53-70页

作者： Dmitry A.Semchonok Jyotirmoy Mondal Connor J.Cooper katrina schlum Meng Li Muhamed Amin Carlos O.S.Sorzano Erney Ramirez-Aportela Panagiotis L.Kastritis Egbert J.Boekema Albert Guskov Barry D.Bruce Groningen Biomolecular Sciences&Biotechnology Institute University of GroningenGroningenthe Netherlands Biochemistry&Cellular and Molecular Biology Department University of TennesseeKnoxvilleTNUSA Program in Genome Science and Technology University of TennesseeKnoxvilleTNUSA Bredesen Center for Interdisciplinary Research&Education University of TennesseeKnoxvilleTNUSA Department of Sciences University College GroningenGroningenthe Netherlands Biocomputing Unit National Center for Biotechnology(CSIC)Darwin 3Campus Universidad Auto´noma de MadridCantoblanco28049 MadridSpain Universidad CEU San Pablo Campus Urb.Monteprı´ncipeBoadilla del Monte28668 MadridSpain Institute of Biochemistry and Biotechnology Martin Luther University Halle-WittenbergHalle/SaaleGermany Microbiology Department University of TennesseeKnoxvilleTNUSA Present address:Institute of Biochemistry and Biotechnology Martin Luther University Halle-WittenbergHalle/SaaleGermany School of Oceanography University of WashingtonSeattleWAUSA

Photosystem I(PSI)is one of two photosystems involved in oxygenic *** of cyanobacteria exists in monomeric,trimeric,and tetrameric forms,in contrast to the strictly monomeric form of PSI in plants and *** tetrameric organization raises questions about its structural,physiological,and evolutionary *** we report the3.72 A˚resolution cryo-electron microscopy structure of tetrameric PSI from the thermophilic,unicellular cyanobacterium Chroococcidiopsis *** structure resolves 44 subunits and 448 cofactor *** conclude that the tetramer is arranged via two different interfaces resulting from a dimer-of-dimers *** localization of chlorophyll molecules permits an excitation energy pathway within and between adjacent *** analysis reveals conserved regions in the PsaL subunit that correlate with the oligomeric *** PSI may function as a key evolutionary step between the trimeric and monomeric forms of PSI organization in photosynthetic organisms.

关键词： cryo-EM photosystem I non-heterocyst-forming cyanobacteria Chroococcidiopsis evolution of chloroplast high light adaptation

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Voices From the Industry:How EdTech Leaders Responded to the COVID-19 Pandemic

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ECNU Review of Education 2024年第2期7卷 420-441页

作者： Deoksoon Kim katrina Borowiec Drina Kei Yatsu Stanton Wortham Boston College Lynch School of Education and Human DevelopmentI40 Commonwealth AvenueChestnut HillMA02467-3800USA

Purpose Educational technology(“EdTech”)served a pivotal role in keeping schools functioning during the beginning of the COVID-19 *** is known about EdTech leaders’roles in shaping this *** study explores EdTech leaders’perspectives and backgrounds,their response to the pandemic,how they envision their roles as educators,and their perspectives about how technology facilitates educational ***/Approach/Methods This study uses a qualitative,phenomenological approach to understand how 11 EdTech leaders experienced the *** were recruited for interviews in summer 2021 via purposive sampling to include diverse backgrounds and *** were analyzed *** The findings show that a four-category typology can be used to describe EdTech leaders’diverse backgrounds and *** emphasized equity and open collaboration in their pandemic responses,by expanding access to their tools and adapting their products as users’needs *** leaders anticipate streamlined user experiences,improvements in online learning,and increased adoption of artificial intelligence and simulated learning ***/Value This study addresses a gap in the research concerning EdTech leaders’perspectives on their efforts to support educators and their experiences during the *** hope this study sparks additional research on EdTech leaders’experiences and roles in education.

关键词： Collaboration COVID-19 pandemic educational technology innovation leadership technology access

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A Spectacle of Tradition and Modernity

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ChinAfrica 2024年第10期16卷 56-57页

作者： katrina JACOB 不详

China Through My Camera programme provides Namibian influencer a chance to get a multidimensional view of the *** graduating in Beijing in 2020 during the tumultuous period of COVID-19,I didn’t think that I would be able to return to China anytime *** pandemic had disrupted lives globally,and like many international students,I was not sure if I would be able to ever set foot in China *** restrictions were stringent,and the idea of returning seemed like a distant dream.

关键词： dream dis get

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A New Era in EdTech:Emerging Challenges and Opportunities

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ECNU Review of Education 2024年第2期7卷 252-257页

作者： Deoksoon Kim katrina Borowiec Stanton Wortham Lynch School of Education and Human Development Chestnut HillMassachusetts 02467-3800USA

The COVID-19 pandemic dramatically expanded the increasingly important role of educational technology(“EdTech”)in K-16 *** is“the introduction of information and technology tools in teaching and learning”(Ganimian et al.,2020,p.5).Examples of EdTech include audio-visual aids,computer-assisted learning,mobile devices,smart technologies,and virtual reality(Huang et al.,2019).One sign of the growing importance of technology in schools is the rapid increase in EdTech investments,which tripled between 2019(pre-COVID)and 2021(during COVID;HolonIQ,2022).Nonetheless,inequality in access to technology remains a barrier for students in underserved schools(Chapman et al.,2010;Dorn et al.,2020).

关键词： smart teaching expanded

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黑客利用“社交工程”入侵IT部门

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商业周刊（中文版） 2024年第2期 18-19页

作者： Margi Murphy katrina Manson 融汐(译) 不详

从许多方面来说,这是一次平淡无奇的交谈。一名IT技术支持部门的员工接了一个电话,自我介绍后问道:“您想问的是关于新机票还是已买机票的?”来电者听起来像是一个20岁出头的美国人,他解释说,他在登录自己的账户时遇到了麻烦:“我不知... 详细信息

从许多方面来说,这是一次平淡无奇的交谈。一名IT技术支持部门的员工接了一个电话,自我介绍后问道:“您想问的是关于新机票还是已买机票的?”来电者听起来像是一个20岁出头的美国人,他解释说,他在登录自己的账户时遇到了麻烦:“我不知道如何重置密码,所以我今天打电话来是要重置密码的。”来电者提供了他的名字,而这个名字与一名员工的名字相符。

关键词： IT技术自我介绍黑客 IT部门密码机票入侵重置

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Measurement and quantification of caking in excipients and food products with emphasis on the non-homogeneous interaction with ambient moisture

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Particuology 2021年第3期19卷 75-83页

作者： katrina Brockbank Brian Armstrong Jamie Clayton Freeman Technology Ltd 1 Miller CourtSevern DriveTewkesburyGloucestershireGL208DNUK

Whilst caking occurs via several different mechanisms,absorption and migration of moisture is frequently the most dominant mechanism within the food and pharmaceutical *** understanding the propensity to cake is important for minimising down-stream process issues,however most characterisation techniques assume that moisture induced caking occurs homogenously through the sample resulting in a uniformly caked powder *** this study,the effect of moisture induced caking on powder flowability was investigated using powder *** materials,including skimmed milk powder(SMP)and sulphated methyl ester(SME)were stored for several days under controlled humidity *** flow energies,a measure of the resistance to flow,were measured at 24 h intervals using an FT4 Powder *** the energy is measured as a function of the bed height,variations in the powder bed are also *** results demonstrated that caking does not always occur uniformly,instead a caked region(or crust)forms at the air-powder interface and then progresses through the powder ***,the strength of this caked region was shown to increase over several days before stabilising.

关键词： Powder Caking Crust formation Powder rheometry Relative humidity

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Alcoholic pancreatitis:Lessons from the liver

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World Journal of Gastroenterology 2010年第11期16卷 1314-1320页

作者： Dahn L Clemens katrina J Mahan Department of Internal Medicine University of Nebraska Medical Center Research Service Veterans Administration Medical Center

The association between alcohol consumption and pancreatitis has been recognized for over 100 years. Despite the fact that this association is well recognized, the mechanisms by which alcohol abuse leads to pancreatic tissue damage are not entirely clear. Alcohol abuse is the major factor associated with pancreatitis in the Western world. Interestingly, although most cases of chronic pancreatitis and many cases of acute pancreatitis are associated with alcohol abuse, only a small percentage of individuals who abuse alcohol develop this disease. This situation is reminiscent of the association between alcohol abuse and the incidence of alcoholic liver disease. The liver and the pancreas are developmentally very closely related. Even though these two organs are quite different, they exhibit a number of general structural and functional similarities. Furthermore, the diseases mediated by alcohol abuse in these organs exhibit some striking similarities. The diseases in both organs are characterized by parenchymal cell damage, activation of stellate cells, aberrant wound healing, and fibrosis. Because of the similarities between the liver and the pancreas, and the alcohol-associated diseases of these organs, we may be able to apply much of the knowledge that we have gained regarding the effects of alcohol on the liver to the pancreas.

关键词： Alcoholic pancreatitis Alcohol metabolism Stellate cells Fibrosis

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Behavioral and physiological flexibility are used by birds to manage energy and support investment in the early stages of reproduction

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Current Zoology 2010年第6期56卷 767-792页

作者： Franois VZINA katrina G. SALVANTE Département de Biologie chimie et géographieGroupe de recherche sur les environnements nordiques BORASUniversité du Québec à Rimouski Department of Biological Sciences Simon Fraser University

Interest in phenotypic flexibility has increased dramatically over the last decade, but flexibility during reproduction has received relatively little attention from avian scientists, despite its possible impact on fitness. Because most avian species maintain atrophied reproductive organs when not active, reproduction in birds requires major tissue remodeling in preparation for breeding. Females undergo rapid （days） recrudescence and regression of their reproductive organs at each breeding attempt, while males grow their organs ahead of time at a much slower rate （weeks） and may maintain them at maximal size throughout the breeding season. Reproduction is associated with significant metabolic costs. Egg production leads to a 22%-27% increase in resting metabolic rate （RMR） over non-reproductive values. This is partly due to the activity of the oviduct, an organ that may allow females to adjust reproductive investment by modulating egg size and quality. In males, gonadal recrudescence may lead to a 30% increase in RMR, but the data are inconsistent and general conclusions regarding energetic costs of reproduction in males will require more research. Recent studies on captive female zebra finches describe the impacts of these costs on daily energy budgets and highlight the strategies used by birds to maintain their investment in reproduction when energy is limited. Whenever possible, birds use behavioral flexibility as a first means of saving energy. Decreasing locomotor activity saves energy during challenges such as egg production or exposure to cold temperatures and is an efficient way to buffer variation in individual daily energy budgets. However, when behavioral flexibility is not possible, birds must rely on flexibility at the physiological level to meet energy demands. In zebra finches breeding in the cold, this results in a reduced pace of laying, likely due to down-regulation of both reproductive and non-reproductive function, allowing females to defend mini

关键词： Phenotypic plasticity Phenotypic flexibility BMR Energy budget Organ Egg size Physiological tradeoff Fitness

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Photocatalytic degradation of Chicago Sky Blue 6B and Benzopurpurin 4B using titanium dioxide thin film

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Journal of Environmental Sciences 2005年第5期17卷 869-872页

作者： Abdul K. Mohammed katrina T. McKenzie Department of Chemistry Winston-Salem State UniversityDepartment of Chemistry North Carolina Agricultural and Technical State University 601 S. Martin Luther King Jr. Drive Winston-Salem North Carolina 27110 USA1601 E. Market Street Greensboro North Carolina 27411 USA

Aqueous solutions of azo dyes undergo degradation to form harmless intermediates and colorless products following irradiation by visible light in the presence of titanium dioxide thin films. The dyes that were studied in this work are： Chicago Sky Blue 6B and Benzopurpurin 4B. Results obtained indicated that complete mineralization of the dyes took place under the experimental conditions. There was an increase in conductivity after the complete mineralization experiments possibly indicating the formation of ions such as NO3^- and SO4^2-. Chemical oxygen demand（COD） measurements show a decrease in organic matter for both dyes following complete degradation. The effect of how changing experimental conditions such as pH, temperature and starting concentrations of dyes affected the rate of dye degradation was measured. There was an increase in the rate of disappearance of the dye color at lower pH. High concentrations of dye solutions reauired Iona dearadation time.

关键词： titanium dioxide photocatalysis photocatalytic degradation azo dyes

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DOCK8 regulates signal transduction events to control immunity

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Cellular & Molecular Immunology 2017年第5期14卷 406-411页

作者： Conor J Kearney katrina L Randall Jane Oliaro Immune Defence Laboratory Cancer Immunology Division The Peter MacCallum Cancer Centre East Melbourne Victoria 3002 Australia Sir Peter MacCallum Department of Oncology The University of Melbourne Parkville Victoria 3052 Australia Department of Immunology and Infectious Disease The John Curtin School of Medical Research Australian National University Acton Australian Capital Territory 2601 Australia Australian National University Medical School Australian National University Acton Australian Capital Territory 2605 Australia

Genetic mutations in the gene encoding DOCK8 cause an autosomal recessive form of hyper immunoglobulin E syndrome （AR-HIES）, referred to as DOCK8 deficiency. DOCK8 deficiency in humans results in the onset of combined immunodeficiency disease （CID）, clinically associated with chronic infections with diverse microbial pathogens, and a predisposition to malignancy. It is now becoming clear that DOCK8 regulates the function of diverse immune cell sub-types, particularly lymphocytes, to drive both innate and adaptive immune responses. Early studies demonstrated that DOCK8 is required for lymphocyte survival, migration and immune synapse formation, which translates to poor pathogen control in the absence of DOCK8. However, more recent advances have pointed to a crucial role for DOCK8 in regulating the signal transduction events that control transcriptional activity, cytokine production and functional polarization of immune cells. Here, we summarize recent advances in our understanding of DOCK8 function, paying particular attention to an emerging role as a signaling intermediate to promote immune responses to diverse external stimuli.

关键词： DOCK8 immunodeficiency lymphocytes NK Cells signal transduction

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