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Development of a sample preparation approach to measure the size of nanoparticle aggregates by electron microscopy

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Particuology 2019年第4期17卷 49-57页

作者： Agnieszka Dudkiewicz angela Lehner Qasim Chaudhry Kristian Molhave Guenter Allmaier Karen Tiede Alistair B.A. Boxall Peter Hofmann John Lewis The Food and Environment Research Agency Sand Hutton York Y041 1LZ UK Department of Environment The University of York Heslington York YO10 5DD UK National Centre for Food Manufacturing The University of Lincoln Holbeach PE12 7AG UK Research Group Bio- and Polymer Analysis Institute of Chemical Technologies and Analytics TU Wien (Vienna University of Technology) Getreidemarkt 9 A-1060 Vienna Austria University of Chester Parkgate Road Chester CH1 4BJ UK Department of Micro and Nanotechnology Technical University of Denmark DTU Bldg 345b Lyngby 2800 Denmark Research Centre for Global Food Security and Ecosystems University of Hohenheim Wollgrasweg 43 70155 Stuttgart Germany Department of Geoinformatics - Z.GIS University of Salzburg Schillerstr. 30 A-5020 Salzburg Austria

Electron microscopy (EM) is widely used for nanoparticle (NP) sizing. Following an initial assessment of two sample preparation protocols described in the current literature as"unperturbed", we found that neither could accurately measure the size of NPs featuring a broad size distribution, e.g., aggregates. Because many real-world NP samples consist of aggregates, this finding was of considerable concern. The data showed that the protocols introduced errors into the measurement by either inducing agglomeration artefacts or providing a skewed size distribution towards small particles (skewing artefact). The focus of this work was to develop and apply a mathematical refinement to correct the skewing artefact. This refinement provided a much improved agreement between EM and a reference methodology, when applied to the measurement of synthetic amorphous silica NPs. Further investigation, highlighted the influence of NP chemistry on the refinement. This study emphasised the urgent need for greater and more detailed consideration regarding the sample preparation of NP aggregates to routinely achieve accurate measurements by EM. This study also provided a novel refinement solution applicable to the size characterisation of silica and c让rate-coated gold NPs featuring broad size distributions. With further research, this approach could be extended to other NP types.

关键词： Nanoparticles Aggregates Measurement Electron microscopy Sample preparation Artefacts

Prickly pairs: the proportion of spinescent species does not differ between islands and mainlands

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Journal of Plant Ecology 2019年第6期12卷 941-948页

作者： Floret L.Meredith Marianne L.Tindall Frank A.Hemmings angela T.Moles Evolution and Ecology Research Centre School of BiologicalEarth and Environmental SciencesUNSW AustraliaSydneyNSW 2052Australia John T.Waterhouse Herbarium School of BiologyEarth and Environmental SciencesUNSW AustraliaSydneyNSW 2052Australia

Aims Organisms on islands are thought to escape biotic pressure and lose defensive ***,broadscale,evidence-based tests of this idea are *** this study,we asked:(i)whether the proportion of spinescent plant species differed between islands and mainlands and(ii)whether the proportion of spinescent species increased with increasing island area and with decreasing island distance to *** We compiled species lists for 18 island–mainland pairs around *** classified 1129 plant species as spinescent or nonspinescent using published species *** Findings There was no significant difference between the proportion of spinescent species found on islands and on *** of spinescent species were not significantly related to island area or distance to *** results suggest that spinescence is just as important to island plants as it is to mainland plants,even for plants inhabiting small or distal *** is unexpected,given prevailing thought and previous work on island–mainland *** study demonstrates the importance of testing well-accepted yet untested ideas.

关键词： herbivory island biogeography theory physical defence plant community plant defence prickles thorns

Dietary-suppression of hepatic lipogenic enzyme expression in intact male transgenic mice

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World Journal of Gastroenterology 2013年第46期19卷 8671-8677页

作者： Maria Notarnicola Maria Gabriella Caruso angela Tafaro Valeria Tutino Giusy Bianco Mario Minoia Antonio Francavilla Laboratory of Nutritional Biochemistry National Institute for Digestive Diseases Animal Facility National Institute for Digestive Diseases Scientific Direction National Institute for Digestive Diseases

AIM:To study,in intact male transgenic mice,the effects of three diets based on olive oil and olive oil diet supplemented with lovastatin and orlistat on hepatic lipogenic enzymes expression,considered markers of cell ***:Forty ApcMin/+mice were randomly divided into 4 groups and fed for 10 wk:olive oil(OO)group,n=10 animals received a diet with olive oil 12%;olive oil plus lovastatin(LOVA)group,n=10 animals received the same diet with olive oil supplemented with lovastatin 5 mg/kg;olive oil plus orlistat(OR)group,n=10 animals fed the diet with olive oil supplemented with orlistat 50 mg/kg and SD group,n=10 animals fed a standard *** activity of lipogenic enzymes and their gene expression were evaluated by radiomet-ric and real-time reverse transcription-polymerase chain reaction assay,***:After 10 wk of dietary treatment,the body weight was no different among animal groups(21.3±3.1 g for standard group,22.1±3.6 g for OO group,22.0±3.2 g for LOVA group and 20.7±3.4 g for OR group,data expressed as mean±SD),observing a generalized well-being in all *** the dietary managed treated groups presented significantly reduced hepatic levels of fatty acid synthase,farnesyl pyrophosphate synthase and 3-hydroxyl-3-methyl-glutaryl CoA reductase activity and gene expression when compared with the mice fed the standard *** evaluate cell proliferation in the liver of treated mice,the levels of cyclin E mRNA have been measured,demonstrating a significant reduction of cyclin E gene expression in all treated *** of reduced hepatic cell proliferation was present overall in OO group ***:We confirm the role of lipogenic enzymes as markers of cell proliferation,suggesting that appropriate dietary management alone or with drugs can be a feasible approach to counteract hepatic cell proliferation in mice.

关键词： Lipogenic enzymes Liver Markers of cell proliferation Transgenic mice Dietary treatment

Why stem/progenitor cells lose their regenerative potential

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World Journal of Stem Cells 2021年第11期13卷 1714-1732页

作者： angela Picerno Alessandra Stasi Rossana Franzin Claudia Curci Ighli di Bari Loreto Gesualdo Fabio Sallustio Department of Emergency and Organ Transplantation University of Bari“Aldo Moro”Bari 70124Italy Department of Interdisciplinary Medicine University of Bari“Aldo Moro”Bari 70124Italy

Nowadays,it is clear that adult stem cells,also called as tissue stem cells,play a central role to repair and maintain the tissue in which they reside by their selfrenewal ability and capacity of differentiating into distinct and specialized *** stem cells age,their renewal ability declines and their capacity to maintain organ homeostasis and regeneration is *** a molecular perspective,these changes in stem cells properties can be due to several types of cell intrinsic injury and DNA aberrant alteration(i.e epigenomic profile)as well as changes in the tissue microenviroment,both into the niche and by systemic circulating ***,it has been suggested that aging-induced deterioration of stem cell functions may play a key role in the pathophysiology of the various agingassociated ***,understanding how resident stem cell age and affects near and distant tissues is ***,we examine the current knowledge about aging mechanisms in several kinds of adult stem cells under physiological and pathological conditions and the principal aging-related changes in number,function and phenotype that determine the loss of tissue renewal ***,we examine the possible cell rejuvenation *** cell rejuvenation may reverse the aging phenotype and the discovery of effective methods for inducing and differentiating pluripotent stem cells for cell replacement therapies could open up new possibilities for treating age-related diseases.

关键词： Stem cells Aging Self-renewal Rejuvenation Aging-associated disorders Epigenetic changes Aging environment

Neurogenesis in the adult olfactory bulb

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Neural Regeneration Research 2011年第8期6卷 575-600页

作者： angela Pignatelli Cristina Gambardella Ottorino Belluzzi Dipartimento di Biologia ed Evoluzione Università degli Studi di FerraraItaly Istituto Nazionale di Neuroscienze Sezione di FerraraItaly

Neurogenesis is the process by which cells divide, migrate, and subsequently differentiate into a neuronal phenotype. Significant rates of neurogenesis persist into adulthood in two brain regions, the subgranular zone of the dentate gyrus and the subventricular zone of the lateral ventricles. Cells of the subventricular zone divide and migrate via the rostral migratory stream to the olfactory bulb where they differentiate into granule and pefiglomerular cells. With the discovery of large-sca^e neurogenesis in the adult brain, there have been significant efforts to identify the mechanisms that control this process as well as the role of these cells in neuronal functioning. Although many questions remain unanswered, new insights appear daily about adult neurogenesis, regulatory mechanisms, and the fates of the progeny. In this review we highlight the main studies investigating factors that regulate neurogenesis in the subventricular zone, neuronal migration to the olfactory bulb, neuronal integration into the existing bulbar network and shortly discuss the functional meaning of this process.

关键词： stem cells adult neurogenesis olfactory bulb rostral migratory stream subventricular zone

Fabrication,microstructures,and optical properties of Yb:Lu_(2)O_(3) laser ceramics from co-precipitated nano-powders

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Journal of Advanced Ceramics 2020年第6期9卷 674-682页

作者： Ziyu LIU Guido TOCI angela PIRRI Barbara PATRIZI Yagang FENG Jiabei WEI Feng WU Zhaoxiang YANG Matteo VANNINI Jiang LI Key Laboratory of Transparent Opto-functional Inorganic Materials Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 201899China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Istituto Nazionale di Ottica Consiglio Nazionale delle RicercheCNR-INOSesto Fiorentino(Fi)50019Italy Istituto di Fisica Applicata“N.Carrara” Consiglio Nazionale delle RicercheCNR-IFACSesto Fiorentino(Fi)50019Italy School of Material Science and Engineering Jiangsu UniversityZhenjiang 212013China

The Yb:Lu_(2)O_(3)precursor made up of spherical particles was synthesized through the co-precipitation method in the water/ethanol *** 5 at% Yb:Lu_(2)O_(3)powder is in the cubic phase after calcination at 1100℃ for 4 *** powder also consists of spherical nanoparticles with the average particle and grain sizes of 96 and 49 nm,*** average grain size of the pre-sintered ceramic sample is 526 nm and that of the sample by hot isostatic pressing grows to 612 *** 1.0 mm-thick sample has an in-line transmittance of 81.6%(theoretical value of 82.2%)at 1100 *** largest absorption cross-section at 976 nm is 0.96×1^(0-20)cm^(2) with the emission cross-section at 1033 nm of 0.92×10^(-20)cm^(2) and the gain cross sections are calculated with the smallest population inversion parameter β of *** highest slope efficiency of 68.7% with the optical efficiency of 65.1% is obtained at 1033.3 nm in quasi-continuous wave(QCW)*** the case of continuous wave(CW)pumping,the highest slope efficiency is 61.0% with the optical efficiency of 54.1%.The obtained laser performance indicates that Yb:Lu_(2)O_(3)ceramics have excellent resistance to thermal load stresses,which shows great potential in high-power solid-state laser applications.

关键词： Yb:Lu_(2)O_(3)transparent ceramics co-precipitated nano-powder spectroscopic properties laser performance hot isostatic pressing

Mapping and predicting a candidate gene for flesh color in watermelon

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Journal of Integrative Agriculture 2021年第8期20卷 2100-2111页

作者： WANG Chao-nan LUAN Fei-shi LIU Hong-yu angela RDAVIS ZHANG Qi-an DAI Zu-yun LIU Shi Key Laboratory of Biology and Genetic Improvement of Horticulture Crops(Northeast Region) Ministry of Agriculture and Rural Affairs/Horticulture and Landscape Architecture CollegeNortheast Agricultural UniversityHarbin 150030P.R.China South Central Agricultural Research Laboratory Agricultural Research ServiceU.S.Department of AgricultureWashingtonD.C.94710USA Horticulture Institute Anhui Academy of Agricultural ScienceHefei 230031P.R.China Anhui Jianghuai Horticulture Technology Co. Ltd.Hefei 230031P.R.China

The color of watermelon flesh is an important trait determined by a series of ***,we used Cream of Saskatchewan(pale yellow flesh)and PI 186490(white flesh)as parental materials for an F2 segregation and initial mapping using the bulked segregant analysis sequencing(BSA-seq)*** BSA results revealed a flesh colorrelated QTL that spans approximately 2.45 Mb on chromosome *** region was preliminarily positioned in a 382-kb segment,and then narrowed down into a 66.8-kb segment with 1260 F2 individuals.A total of nine candidate genes were in the fine mapping interval,but only Cla007528(encoding chlorophyllase)had non-synonymous mutations and was significantly expressed between the parental materials throughout flesh *** also checked the expression patterns of the carotenoid metabolic pathway genes based on RNA-seq data and qRT-PCR *** genes in the xanthophyll cycle(ClCHYB,ClNCED-1 and ClNCED-7)exhibited differential expression patterns between the two parental lines at different flesh color formation ***1,ClPDS,ClZDS,ClCHXE,ClCRTISO and ClLCYB also exhibited clearly different expression patterns accompanied by carotenoid accumulation.

关键词： watermelon fine mapping flesh color QTL transcriptome

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Hidden Treasure

China International Business 2010年第4期 24-25页

作者： angela SNOWBALL

It＇s midday and the restaurant is humming with the lunchtime set. Waiters carve Peking duck before hungry office workers and place steaming baskets of char siu and shrimp dumplings on *** to 1949 - The Hidden City. T... 详细信息

关键词：隐藏上班族公寓楼

Current protocol to achieve dental movement acceleration and pain control with Photo-biomodulation

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World Journal of Methodology 2023年第5期13卷 379-383页

作者： angela Dominguez Department of Orthodontics Faculty of DentistryBenemerita Universidad Autónoma de PueblaZaragoza de Puebla Calle 4 Sur 104PueblaC.P.72000Mexico

When designing a study on dental movement acceleration or pain control during orthodontic treatment,it is crucial to consider effective *** objective of this editorial is to compile the most effective parameters supported by evidence that should be considered in future studies to achieve complete parameter *** protocol currently recommended to homogenize the parameters and facilitate the development of further meta-analysis in terms of acceleration of movement and pain control in orthodontics is Wavelength:810 nm,2.2 J per surface,0.1 W in continuous mode/0.1 W average power in a superpulsed,sweeping movement,1mm from the mucosa,22 seconds along the vestibular surface and 22 seconds along the lingual surface,the recommended speed of movement is 2 mm/sec,1 application during each orthodontic control,to achieve dental movement acceleration and repeat the dose at 24 h to ensure pain *** energy density and power density will depend on the spot size used in the equipment and the distance from the *** will strengthen the evidence of photobiomodulation as the best therapy to accelerate tooth movement and at the same time control the pain produced by orthodontic treatments.

关键词： Photobiomodulation Laser-assisted orthodontics Dental movement acceleration Pain control Diode laser