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Revealing the nature of optical activity in carbon dots produced from different chiral precursor molecules

Light(Science & Applications) 2022年第5期11卷 855-867页

作者： Ananya Das Evgeny v.Kundelev Anna A.vedernikova sergei A.Cherevkov Denis v.Danilov Aleksandra v.Koroleva Evgeniy v.Zhizhin Anton N.Tsypkin Aleksandr P.Litvin Alexander v.Baranov Anatoly v.Fedorov Elena v.Ushakova Andrey L.Rogach Center of Information Optical Technologies ITMO UniversitySaint Petersburg 197101Russia Research Park Saint Petersburg State UniversitySaint Petersburg 199034Russia Laboratory of Femtosecond Optics and Femtotechnology ITMO UniversitySaint Petersburg 197101Russia Laboratory of Quantum Processes and Measurements ITMO UniversitySaint Petersburg 197101Russia Department of Materials Science and Engineering and Centre for Functional Photonics(CFP)City University of Hong KongKowloonHong Kong SAR 999077China Shenzhen Research Institute City University of Hong KongShenzhen 518057China

Carbon dots(CDs)are light-emitting nanoparticles that show great promise for applications in biology and medicine due to the ease of fabrication,biocompatibility,and attractive optical *** chirality,on the other hand,is an intrinsic feature inherent in many objects in nature,and it can play an important role in the formation of artificial complexes based on CDs that are implemented for enantiomer recognition,site-specific bonding,*** employed a one-step hydrothermal synthesis to produce chiral CDs from the commonly used precursors citric acid and ethylenediamine together with a set of different chiral precursors,namely,L-isomers of cysteine,glutathione,phenylglycine,and *** resulting CDs consisted of O,N-doped(and also S-doped,in some cases)carbonized cores with surfaces rich in amide and hydroxyl groups;they exhibited high photoluminescence quantum yields reaching 57%,chiral optical signals in the Uv and visible spectral regions,and two-photon *** signals of CDs were rather complex and originated from a combination of the chiral precursors attached to the CD surface,hybridization of lower-energy levels of chiral chromophores formed within CDs,and intrinsic chirality of the CD *** DFT analysis,we showed how incorporation of the chiral precursors at the optical centers induced a strong response in their circular dichroism *** optical characteristics of these CDs,which can easily be dispersed in solvents of different polarities,remained stable during pH changes in the environment and after Uv exposure for more than 400 min,which opens a wide range of bio-applications.

关键词： properties chiral carbon

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Delineating complex ferroelectric domain structures via second harmonic generation spectral imaging

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Journal of Materiomics 2023年第2期9卷 395-402页

作者： Wei Li Yunpeng Ma Tianyi Feng Ziwan Du Yixuan Liu sergei vKalinin Jing-Feng Li Qian Li State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China Department of Materials Science and Engineering University of Tennessee KnoxvilleKnoxvilleTN37996USA

Understanding the mechanisms and spatial correlations of crystallographic symmetry breaking in ferroelectric materials is essential to tuning their functional *** optical second harmonic generation(SHG)has long been utilized in ferroelectric studies,its capability for probing complex polar materials has yet to be fully ***,we develop a SHG spectral imaging method implemented on a home-designed laser-scanning SHG microscope,and demonstrate its application for a model system of(K,Na)NbO3 single *** model fitting analysis produces comprehensive information about the polarization vector orientations and relative fractions of constituent domain variants as well as their thermal evolution across the polymorphic phase *** domains and phases are clearly delineated at different temperatures,suggesting the phase competitions in(K,Na)***,we show that unsupervised matrix decomposition analysis can quickly and faithfully reveal domain configurations without a priori knowledge about specific material *** SHG spectral imaging method can be readily extended to other ferroelectric materials with potentials to be further enhanced.

关键词： Second harmonic generation Ferroelectrics Domain structure Bayes linear unmixing

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Antiviral adsorption activity of porous silicon nanoparticles against different pathogenic human viruses

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Bioactive Materials 2022年第1期7卷 39-46页

作者： Liubov A.Osminkina Svetlana N.Agafilushkina Ekaterina A.Kropotkina Nikolay Yu Saushkin Ivan v.Bozhev sergei S.Abramchuk Jeanne v.Samsonova Alexandra S.Gambaryan Lomonosov Moscow State University Physics DepartmentLeninskie Gory 1119991MoscowRussian Federation Institute for Biological Instrumentation of Russian Academy of Sciences 142290PushchinoMoscow RegionRussian Federation Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products Russian Academy of Sciences108819MoscowRussian Federation Lomonosov Moscow State University Faculty of ChemistryLeninskie Gory 1119991MoscowRussian Federation Quantum Technology Center Lomonosov Moscow State UniversityPhysics DepartmentLeninskie Gory 1119991MoscowRussian Federation A.N.Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences Vavilova 28119991MoscowRussian Federation

New viral infections,due to their rapid spread,lack of effective antiviral drugs and vaccines,kill millions of people every *** global pandemic SARS-Cov-2 in 2019-2021 has shown that new strains of viruses can widespread very quickly,causing disease and death,with significant socio-economic ***,the search for new methods of combating different pathogenic viruses is an urgent task,and strategies based on nanoparticles are of significant *** work demonstrates the antiviral adsorption(virucidal)efficacy of nanoparticles of porous silicon(PSi NPs)against various enveloped and non-enveloped pathogenic human viruses,such as Influenza A virus,Poliovirus,Human immunodeficiency virus,West Nile virus,and Hepatitis *** NPs sized 60 nm with the average pore diameter of 2 nm and specific surface area of 200 m^(2)/g were obtained by ball-milling of electrochemically-etched microporous silicon *** interaction with PSi NPs,a strong suppression of the infectious activity of the virus-contaminated fluid was observed,which was manifested in a decrease in the infectious titer of all studied types of viruses by approximately 104 times,and corresponded to an inactivation of 99.99%viruses in *** sorption capacity of PSi NPs is possible due to their microporous structure and huge specific surface area,which ensures efficient capture of virions,as confirmed by ELISA analysis,dynamic light scattering measurements and transmission electron microscopy *** results obtained indicate the great potential of using PSi NPs as universal viral sorbents and disinfectants for the detection and treatment of viral diseases.

关键词： Pathogenic human viruses Porous silicon nanoparticles virus Antiviral activity virucide

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Evolutionary relationships of mitogenomes in a recently radiated Old World avian family

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Avian Research 2023年第2期14卷 153-159页

作者： Wenqing Zang Zhiyong Jiang Per G.P.Ericson Gang Song sergei vDrovetski Takema Saitoh Fumin Lei Yanhua Qu Key Laboratory of Zoological Systematics and Evolution Institute of ZoologyChinese Academy of SciencesBeijingChina College of Life Sciences University of Chinese Academy of SciencesBeijingChina Department of Bioinformatics and Genetics Swedish Museum of Natural HistoryPO Box 50007SE-10405StockholmSweden Laboratories of Analytical Biology National Museum of Natural HistorySmithsonian InstitutionWashingtonDC 20004USA U.S.Geological Survey Eastern Ecological Science Center at Patuxent Research RefugeLaurelMD 20708USA Yamashina Institute for Ornithology AbikoChibaJapan Center for Excellence in Animal Evolution and Genetics Chinese Academy of SciencesKunming650223China

Environmentally heterogeneous mountains provide opportunities for rapid diversification and *** family Prunellidae(accentors)is a group of birds comprising primarily mountain specialists that have recently radiated across the Palearctic *** rapid diversification poses challenges to resolving their *** we sequenced the complete mitogenomes and estimated the phylogeny using all 12(including 28 individuals)currently recognized species of *** reconstructed the mitochondrial genome phylogeny using 13 protein-coding genes of 12 species and 2 Eurasian Tree Sparrows(Passer montanus).Phylogenetic relationships were estimated using a suite of analyses:maximum likelihood,maximum parsimony and the coalescent-based *** times were estimated by implementing a Bayesian relaxed clock model in *** on the BEAST time-calibrated tree,we implemented an ancestral area reconstruction using RASP *** phylogenies based on the maximum likelihood,maximum parsimony and SvDquartets approaches support a clade of large-sized accentors(subgenus Laiscopus)to be sister to all other accentors with small size(subgenus Prunella).In addition,the trees also support the sister relationship of *** and ***+*** with 100%bootstrap support,but the relationships among the remaining eight species in the Prunella clade are poorly *** species cluster in different positions in the three phylogenetic trees and the nodes are often poorly *** five nodes separating the seven species diverged simultaneously within less than half million years(i.e.,between 2.71 and 3.15 million years ago),suggesting that the recent radiation is likely responsible for rampant incomplete lineage sorting and gene tree *** area reconstruction indicates a central Palearctic region origin for *** study highlights that whole mitochondrial genome phylogeny can resolve major lineages within Prun

关键词： Incomplete lineage sorting Mitochondrial genome Mountain specialists Radiation

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E-beam manipulation of Si atoms on graphene edges with an aberration-corrected scanning transmission electron microscope

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Nano Research 2018年第12期11卷 6217-6226页

作者： Ondrej Dyck Songkil Kim sergei v.Kalinin Stephen Jesse Center for Nanophase Materials Science Oak Ridge National LaboratoryOak RidgeTN 37830USA Institute for Functional Imaging of Materials Oak Ridge National LaboratoryOak RidgeTN 37830USA School of Mechanical Engineering Pusan National UniversityBusan 46241Republic of Korea

The burgeoning field of atomic-level material control holds great promise for future breakthroughs in quantum and memristive device manufacture and fundamental studies of atomic-scale chemistry. Realization of atom-by-atom control of matter represents a complex and ongoing challenge. Here, we explore the feasibility of controllable motion of dopant Si atoms at the edges of graphene via the sub-atomically focused electron beam in a scanning transmission electron microscope. We demonstrate that the graphene edges can be cleaned of Si atoms and then subsequently replenished from nearby source material. It is also shown how Si edge atoms may be “pushed” from the edge of a small hole into the bulk of the graphene lattice and from the bulk of the lattice back to the edge. This is accomplished through sputtering of the edge of the graphene lattice to bury or uncover Si dopant atoms. Finally, we demonstrate e-beam mediated hole healing and incorporation of dopant atoms. These experiments form an initial step toward general atomic-scale material control.

关键词： atomic manipulation graphene scanning transmission electron microscopy edge passivation silicon dopant electron beam dynamics

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Learning surface molecular structures via machine vision

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npj Computational Materials 2017年第1期3卷 194-202页

作者： Maxim Ziatdinov Artem Maksov sergei v.Kalinin Institute for Functional Imaging of Materials Oak Ridge National LaboratoryOak RidgeTN 37831USA Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA Bredesen Center for Interdisciplinary Research University of TennesseeKnoxvilleTN 37996USA

Recent advances in high resolution scanning transmission electron and scanning probe microscopies have allowed researchers to perform measurements of materials structural parameters and functional properties in real space with a picometre *** many technologically relevant atomic and/or molecular systems,however,the information of interest is distributed spatially in a non-uniform manner and may have a complex multi-dimensional *** of the critical issues,therefore,lies in being able to accurately identify(‘read out’)all the individual building blocks in different atomic/molecular architectures,as well as more complex patterns that these blocks may form,on a scale of hundreds and thousands of individual atomic/molecular *** we employ machine vision to read and recognize complex molecular assemblies on ***,we combine Markov random field model and convolutional neural networks to classify structural and rotational states of all individual building blocks in molecular assembly on the metallic surface visualized in high-resolution scanning tunneling microscopy *** show how the obtained full decoding of the system allows us to directly construct a pair density function—a centerpiece in analysis of disorderproperty relationship paradigm—as well as to analyze spatial correlations between multiple order parameters at the nanoscale,and elucidate reaction pathway involving molecular conformation *** method represents a significant shift in our way of analyzing atomic and/or molecular resolved microscopic images and can be applied to variety of other microscopic measurements of structural,electronic,and magnetic orders in different condensed matter systems.

关键词： allowed classify spatially

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Post-Late Paleozoic Collisional Framework of Southern Great Altai

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Acta Geologica Sinica(English Edition) 2012年第5期86卷 1093-1104页

作者： Boris M. CHIKOv sergei v. ZINOvIEv Еugene v. DEYEv Institute of Geology Siberian Branch of Russian Academy of Sciences Novosibirsk 630090 Russia

We outline the post-Late Paleozoic （latest Permian to Cenozoic） collisional framework of the southern Great Altai （Central Asia） produced by the convergence between the Tuva-Mongolia and Junggar continental terranes （microplates）. The collisional structures in the region classified on the basis of their geometry and deformation style, dynamic metamorphism, and compositions of tectonites are of three main types：（1） mosaic terranes made up of large weakly deformed Paleozoic blocks separated by younger shear zones; （2） contractional deformation systems involving structures formed in post-Late Paleozoic time, parallel faults oriented along collisional deformation systems, and relict lenses of Paleozoic orogenic complexes; and （3） isolated zones of dynamic metamorphism composed mostly of collisional tectonites different in composition and alteration grade.

关键词： continental collision post-Late Paleozoic events tectonic framework dynamic metamorphism Altai Central Asia

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Crystal-field levels of Nd3+ in a new langasite compound Nd3CrGe3Be2O14

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Journal of Rare Earths 2019年第11期37卷 1250-1254页

作者： sergei A.Klimin Boris v.Mill Marina N.Popova Institute of Spectroscopy Russian Academy of SciencesTroitskMoscow 108840Russia Faculty of Physics M.V.Lomonosov Moscow State UniversityMoscow 119991Russia

We report on the crystal-field(CF)levels of Nd^3+in Nd3CrGe3Be2O14,a representative of recently synthesized Be-containing *** are the first in the family to contain two magnetic subsystems,1 D chromium and Kagome-like rare-earth ***-resolution broad-band temperature-dependent spectra allow us to find all five CF Kramers doublets of the ground 4I9/2 CF multiplet and 38 levels of the excited 4I11/2,13/2,15/2,4F3/2,4F5/2+2H9/2,4F7/2+4S3/2 and 4F9/2 CF *** data form a basis for a future exploration of this interesting two-sublattice magnet with frustrated *** transitions between Kramers doublets of Nd^3+indicate magnetic activity of 1D-chromium chains at T<20 K.

关键词： Langasite Two magnetic subsystems High-resolution spectroscopy Crystal-field levels Magnetic correlations Rare earths

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Off-the-shelf deep learning is not enough,and requires parsimony,Bayesianity,and causality

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npj Computational Materials 2021年第1期7卷 133-138页

作者： Rama K.vasudevan Maxim Ziatdinov Lukas vlcek sergei.v.Kalinin Center for Nanophase Materials Sciences Oak RidgeTN 37831USA Computational Sciences and Engineering Division Oak RidgeTN 37831USA Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Present address:Bayer St.LouisMO 63141USA

Deep neural networks(‘deep learning’)have emerged as a technology of choice to tackle problems in speech recognition,computer vision,finance,***,adoption of deep learning in physical domains brings substantial challenges stemming from the correlative nature of deep learning methods compared to the causal,hypothesis driven nature of modern *** argue that the broad adoption of Bayesian methods incorporating prior knowledge,development of solutions with incorporated physical constraints and parsimonious structural descriptors and generative models,and ultimately adoption of causal models,offers a path forward for fundamental and applied research.

关键词： learning enough finance

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Synaptic receptors for low pH in extracellular space:metabotropic receptors are an underestimated factor in stroke

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Neural Regeneration Research 2020年第11期15卷 2033-2034页

作者： sergei v.Fedorovich Tatsiana G.Dubouskaya Tatsiana v.Waseem Institute of Biophysics and Cell Engineering MinskBelarus Department of Biochemistry Belarusian State UniversityMinskBelarus Department of Pharmacology University of OxfordOxfordUK(Waseem TV)

In the brain,extracellular pH could decrease in certain ***,however,is especially attributable for *** accumulation in the absence of anaerobic respiration is the main,but not the only,reason for lowering pH in this condition(Wemmie et al.,2013).In addition,local pH changes in the synaptic cleft may result from the release of acidic content of synaptic vesicles(Sinning and Hubner,2013).Acidification is able to damage or even kill a *** damaging effect of low pH can be mediated by a direct effect of protons on enzymes or transport *** can also,however,be mediated by specific receptors(Wemmie et al.,2013;Levin and Buck,2015).The most well studied class of pH receptors is ionotropic acid-sensing ion channels(ASIC).These are ion channels which are permeable for sodium and *** open in response to extracellular *** of these receptors could lead to neuronal death(Wemmie et al.,2013).ASIC-induced neuronal death is appeared to be involved in stroke-induced brain *** suggestion is supported by the fact that amiloride,which inhibits ASIC,has a neuroprotective effect in stroke(Xiong et al.,2004).

关键词： al. protective damage

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