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Aero-thermo-elastic Numerical Calculation and Analysis of Spinning Rocket

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Transactions of Nanjing University of Aeronautics and Astronautics 2014年第6期31卷 681-687页

作者：陈东阳 Laith K.Abbas 芮筱亭 Marzocca Piergiovanni 王国平 Institute of Launch Dynamics Nanjing University of Science and Technology department of Mechanical and Aerospace engineering The Wallace H.Coulter School of EngineeringClarkson University

The application of computational fluid dynamics/computational solid method(CFD/CSM)on solving the aero-thermo-elastic problem of spinning rocket is ***,the aerodynamic coefficients of a rocket are calculated,and the results are compared with the available experimental data,which verified the accuracy of the CFD ***,analysis is carried using ANSYS Workbench multi-physics coupling platform,which includes fluid,thermal,and structural *** results show that spinning causes a significant effect on the deformations and ***,thermal stresses due to high temperature at the rocket warhead and tail edges have a dominated effect,even more than those produced by aerodynamic ***,this important outcome should be taken into consideration during the rocket design stages.

关键词： ANSYS Workbench numerical calculation thermal stress spinning

Virtual Staining,Segmentation,and Classification of Blood Smears for Label-Free hematology Analysis

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biomedical engineering Frontiers 2022年第1期3卷 309-322页

作者： Nischita Kaza Ashkan Ojaghi Francisco E.Robles School of Electrical and Computer engineering Georgia Institute of TechnologyAtlantaGeorgiaUSA wallace h.coulter department of biomedical engineering Georgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA

Objective and Impact *** present a fully automated hematological analysis framework based on single-channel(single-wavelength),label-free deep-ultraviolet(UV)microscopy that serves as a fast,cost-effective alternative to conventional hematology *** analysis is essential for the diagnosis and monitoring of several diseases but requires complex systems operated by trained personnel,costly chemical reagents,and lengthy ***-free techniques eliminate the need for staining or additional preprocessing and can lead to faster analysis and a simpler *** this work,we leverage the unique capabilities of deep-UV microscopy as a label-free,molecular imaging technique to develop a deep learning-based pipeline that enables virtual staining,segmentation,classification,and counting of white blood cells(WBCs)in single-channel images of peripheral blood *** train independent deep networks to virtually stain and segment grayscale images of *** segmented images are then used to train a classifier to yield a quantitative five-part WBC *** virtual staining scheme accurately recapitulates the appearance of cells under conventional Giemsa staining,the gold standard in *** trained cellular and nuclear segmentation networks achieve high accuracy,and the classifier can achieve a quantitative five-part differential on unseen test *** proposed automated hematology analysis framework could greatly simplify and improve current complete blood count and blood smear analysis and lead to the development of a simple,fast,and low-cost,point-of-care hematology analyzer.

关键词： networks classifier Blood

Inhibition of retroviral Gag assembly by non-silencing miRNAs promotes autophagic viral degradation

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Protein & Cell 2018年第7期9卷 640-651页

作者： Na Qu Zhao Ma Mengrao Zhang Muaz N. Rushdi Christopher J. Krueger Antony K. Chen department of biomedical engineering College of Engineering Peking University Beijing 100871 China wallace h.coulter department of biomedical-engineering Georgia Institute of Technology Atlanta GA 30332 USA

We recently reported an unconventional mechanism by which miRNAs inhibit hIV-1 viral production. This occurs when miRNAs bind nonspecifically to the viral structural protein Gag, interfering with viral RNA-medi- ated Gag assembly at the plasma membrane. Conse- quently, misassembled viral complexes are redirected into the endocytic pathway where they are delivered to lysosomes for degradation. In this study, we demon- strate that autophagy is a critical mediator of the viral degradation pathway and that this pathway is not hIV-1 specific. Misassembled viral complexes were found to colocalize extensively with LC3 and p62 in late endo- somesllysosomes, demonstrating a convergence of autophagy with functional degradative compartments. Knocking down autophagosome formation machineries reduced this convergence, while treatment with autop- hagy-inducer rapamycin enhanced the convergence. Furthermore, similar autophagy-dependent nonspecific miRNA inhibition of murine leukemia virus （MLV） assembly was shown. Overall, these results reveal autophagy as a crucial regulator of the retroviral degradation pathway in host cells initiated by non- specific miRNA-Gag interactions. These findings could have significant implications for understanding how cells may regulate retroviral complex assembly by miRNA expression and autophagy, and raise the possi- bility that similar regulations can occur in other biolog- ical contexts.

关键词： microRNA Gag protein autophagy

engineering Novel Molecular Beacon Constructs to Study Intracellular RNA Dynamics and Localization

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Genomics, Proteomics & Bioinformatics 2017年第5期15卷 279-286页

作者： Zhao Ma Xiaotian Wu Christopher J.Krueger Antony K.Chen department of biomedical engineering College of Engineering Peking University Beijing 100871 China wallace h.coulter department of biomedical engineering Georgia Institute of Technology Atlanta GA 30332 USA

With numerous advancements in novel biochemical techniques, our knowledge of the role of RNAs in the regulation of cellular physiology and pathology has grown significantly over the past several decades. Nevertheless, detailed information regarding RNA processing, trafficking, and localization in living cells has been lacking due to technical limitations in imaging single RNA transcripts in living cells with high spatial and temporal resolution. In this review, we discuss tech- niques that have shown great promise for single RNA imaging, followed by highlights in our recent work in the development of molecular beacons （MBs）, a class of nanoscale oligonucleotide-probes, for detecting individual RNA transcripts in living cells. With further refinement of MB design and development of more sophisticated fluorescence microscopy techniques, we envision that MB-based approaches could promote new discoveries of RNA functions and activities.

关键词： Y-O-methyl RNA Phosphorothioate Molecular beacon RNA dynamics Single-molecule RNAimaging

Raster-scanning Donut simplifies MINFLUX and provides alternative implement on other scanning-based microscopes

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Light(Science & Applications) 2022年第10期11卷 2271-2275页

作者： Xinzhu Xu Shu Jia Peng Xi department of biomedical engineering College of Future TechnologyPeking UniversityBeijing 100871China wallace h.coulter department of biomedical engineering Georgia Institute of Technology and Emory UniversityAtlantaGeorgia 30332USA UTS-SUStech Joint Research Centre for Bio-medical Materials&Devices Department of Biomedical EngineeringCollege of EngineeringSouthern University of Science and TechnologyShenzhenGuangdong 518055China National biomedical Imaging Center Peking UniversityBeijing 100871China

A donut excitation moves around a single molecule with a zigzag configuration lattice by *** a method implemented in scanning fluorescence microscopy simplifies the conventional MINFLUX *** of hollow zero-intensity excitation,single-pixel detection,time-correlated single photon counting,and drift stabilization,the system achieves localization precision and resolution very close to conventional MINFLUX theoretically and *** averaged high-SNR reference,and pixel-registered intensity from a single molecule is essential to reconstruct localization in maximum likelihood *** performance reaching nearly conventional MINFLUX's,the proposed raster-scanning MINFLUX can inspire researchers expertized in STED or confocal setup to quickly transform to MINFLUX and develop for further exploring on bio-specimens or optical applications.

关键词： scanning excitation stabilization

Rational design and synthesis of noble-metal nanoframes for catalytic and photonic applications

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National Science Review 2016年第4期3卷 520-533页

作者： Xue Wang Aleksey Ruditskiy Younan Xia The wallace h.coulter department of biomedical engineering Georgia Institute of Technology and Emory University State Key Laboratory for Oxo Synthesis and Selective Oxidation Suzhou Research InstituteLanzhou Institute of Chemical PhysicsChinese Academy of Sciences School of Chemistry and Biochemistry Georgia Institute of Technology

Nanoframes are unique for their 3D,highly open *** made of noble metals,they are atractive for use as heterogeneous catalysts because of their large speciic surface areas,high densities of catalytically active sites and low vulnerability toward *** promise to enhance the catalytic activity and durability while reducing the material loading and *** nanoframes composed of Au and/or Ag,they also exhibit highly tunable plasmonic properties similar to those of *** article presents a brief account of recent progress in the design,synthesis and utilization of noble-metal *** start with a discussion of the synthetic strategies,including those involving site-selected deposition and etching,as well as dealloying of both hollow and solid *** then highlight some of the applications enabled by noble-metal ***,we discuss the challenges and trends with regard to future development.

关键词： noble metal nanoframe nanomaterial synthesis catalysis plasmonics

Lipid nanoparticles deliver mRNA to the blood-brain barrier

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Nano Research 2024年第10期17卷 9126-9134页

作者： Yanina Kuzminich Avraham Shakked Randi Calkins Sebastian Rudden Camille Jones Jessie Doan Bora Jang Elisa Schrader Echeverri Ryan Zenhausern Liming Lian David Loughrey hannah E.Peck Rachelle Wiese Dorothy Koveal Philip J.Santangelo James E.Dahlman George C.Woodruff School of Mechanical engineering Georgia Institute of TechnologyAtlantaGA 30332USA Parker h.Petit Institute for Bioengineering and Biosciences Georgia Institute of TechnologyAtlantaGA 30332USA wallace h.coulter department of biomedical engineering Emory University School of Medicine and Georgia Institute of TechnologyAtlantaGA 30332USA

Lipid nanoparticles(LNPs)have delivered RNA to hepatocytes in patients after intravenous *** clinical data support efforts to design LNPs that transfect cells in the central nervous system(CNS).however,delivery to the CNS has been difficult,in large part because quantifying on-target delivery alongside common off-target cell types in adult mice remains *** we report methods to isolate different cell types from the CNS,and subsequently present mRNA delivery readouts using a liver-detargeted *** data suggest that LNPs without targeting ligands can transfect cerebral endothelial cells in mice after intravenous *** the difficulty of crossing the blood-brain barrier,they also underscore the value of quantifying delivery in the CNS with cell-type resolution instead of whole-tissue resolution.

关键词： lipid nanoparticle mRNA nanomedicine central nervous system blood-brain barrier

Color-coded perfluorocarbon nanodroplets for multiplexed ultrasound and photoacoustic imaging

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Nano Research 2019年第4期12卷 741-747页

作者： Daniela Y. Santiesteban Kristina A. hallam Steven K. Yarmoska Stanislav Y. Emelianov wallace h. coulter department of biomedical engineering Georgia Institute of Technology and Emory University Atlanta GA 30332 USA School of Electrical & Computer engineering Georgia Institute of Technology Atlanta GA 30332 USA

Laser-activated perfluorocarb on n anodroplets are an emerging class of phase-cha nge, dual-c ontrast age nts that can be utilized in ultraso und and photoacoustic imaging. Through the ability to differe ntiate subpopulations of nano droplets via laser activatio n at differe nt wavelengths of n ear-infrared light, optically-triggered color-coded perfluorocarb on nano droplets prese nt themselves as an attractive tool for multiplexed ultrasound and photoacoustic imaging. In particular, laser-activated droplets can be used to provide quantitative spatiotemporal information regarding distinct biological targets, allowing for their potential use in a wide range of diagnostic and therapeutic applications. In the work prese nted, laser-activated color-coded perfluorocarb on nan odroplets are syn thesized to selectively resp ond to laser irradiati on at corresp on ding wavele ngths. The dyn amic ultraso und and photoacoustic signals produced by laser-activated perfluorocarbon nano droplets are evaluated in situ prior to implementation in a murine model. In vivo, these particles are used to distinguish unique particle trafficking mechanisms and are show n to provide ultraso und and photoacoustic contrast for up to 72 hours within lymphatics. Overall, the con ducted studies show that laser-activated color-coded perfluorocarbo n nano droplets are a promising agent for multiplexed ultraso und and photoacoustic imaging.

关键词： multiplexed imaging perfluorocarbon nanodroplets photoacoustic imaging ultrasound imaging molecular targets

Progress and Challenges for Live-cell Imaging of Genomic Loci Using CRISPR-based Platforms

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Genomics, Proteomics & Bioinformatics 2019年第2期17卷 119-128页

作者： Xiaotian Wu Shiqi Mao Yachen Ying Christopher J.Krueger Antony K. Chen department of biomedical engineering College of Engineering Peking University Beijing 100871 China School of Life Sciences Peking University Beijing 100871 China wallace h.coulter department of biomedical engineering Georgia Institute of Technology Atlanta GA 30332 USA

Chromatin conformation,localization,and dynamics are crucial regulators of cellular behaviors. Although fluorescence in situ hybridization-based techniques have been widely utilized for investigating chromatin architectures in healthy and diseased states,the requirement for cell fix-ation precludes the comprehensive dynamic analysis necessary to fully understand chromatin activ-ities. This has spurred the development and application of a variety of imaging methodologies for visualizing single chromosomal loci in the native cellular context. In this review,we describe currently-available approaches for imaging single genomic loci in cells,with special focus on clus-tered regularly interspaced short palindromic repeats (CRISPR)-based imaging approaches. In addition,we discuss some of the challenges that limit the application of CRISPR-based genomic imaging approaches,and potential solutions to address these challenges. We anticipate that,with continued refinement of CRISPR-based imaging techniques,significant understanding can be gained to help decipher chromatin activities and their relevance to cellular physiology and pathogenesis.

关键词： CRISPR Cas9 dCas9 Genomic imaging sgRNA