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Single particle electron microscopy

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https://www.readbyqxmd.com/read/28448907/characterization-of-typical-metal-particles-during-haze-episodes-in-shanghai-china
#1
Rui Li, Xin Yang, Hongbo Fu, Qingqing Hu, Liwu Zhang, Jianmin Chen
Aerosol particles were collected during three heavy haze episodes at Shanghai in the winter of 2013. Transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy was used to study the morphology and speciation of typical metal particles at a single-particle level. In addition, time-of-flight aerosol mass spectrometry (ATOFMS) was applied to identify the speciation of the Fe-containing particles. TEM analysis indicated that various metal-containing particles were hosted by sulfates, nitrates, and oxides...
April 19, 2017: Chemosphere
https://www.readbyqxmd.com/read/28448005/open-source-single-particle-analysis-for-super-resolution-microscopy-with-virusmapper
#2
Robert D M Gray, Jason Mercer, Ricardo Henriques
Super-resolution fluorescence microscopy is currently revolutionizing cell biology research. Its capacity to break the resolution limit of around 300 nm allows for the routine imaging of nanoscale biological complexes and processes. This increase in resolution also means that methods popular in electron microscopy, such as single-particle analysis, can readily be applied to super-resolution fluorescence microscopy. By combining this analytical approach with super-resolution optical imaging, it becomes possible to take advantage of the molecule-specific labeling capacity of fluorescence microscopy to generate structural maps of molecular elements within a metastable structure...
April 9, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28437792/phase-plate-cryo-em-structure-of-a-class-b-gpcr-g-protein-complex
#3
Yi-Lynn Liang, Maryam Khoshouei, Mazdak Radjainia, Yan Zhang, Alisa Glukhova, Jeffrey Tarrasch, David M Thal, Sebastian G B Furness, George Christopoulos, Thomas Coudrat, Radostin Danev, Wolfgang Baumeister, Laurence J Miller, Arthur Christopoulos, Brian K Kobilka, Denise Wootten, Georgios Skiniotis, Patrick M Sexton
Class B G-protein-coupled receptors are major targets for the treatment of chronic diseases, such as osteoporosis, diabetes and obesity. Here we report the structure of a full-length class B receptor, the calcitonin receptor, in complex with peptide ligand and heterotrimeric Gαsβγ protein determined by Volta phase-plate single-particle cryo-electron microscopy. The peptide agonist engages the receptor by binding to an extended hydrophobic pocket facilitated by the large outward movement of the extracellular ends of transmembrane helices 6 and 7...
April 24, 2017: Nature
https://www.readbyqxmd.com/read/28437606/transfer-study-of-silver-nanoparticles-in-poultry-production
#4
Federica Gallocchio, Giancarlo Biancotto, Veronica Cibin, Carmen Losasso, Simone Belluco, Ruud Peters, Greet van Bemmel, Claudia Cascio, Stefan Weigel, Peter Tromp, Federica Gobbo, Salvatore Catania, Antonia Ricci
Silver nanoparticles (AgNPs) are of interest due to their antimicrobial activity and are seen as potential candidates to replace antibiotics in animal husbandry. A few studies have focused on this new application, but they lack any considerations about residual accumulation of AgNPs in edible animal tissues and animal products. In this research, a 22 day in vivo study was carried out by oral administration of 20 nm spherical PVP coated AgNPs to hens. Six doses of approximately 1 mg kg(-1) of AgNPs-PVP each were administered to animals throughout the experimentation...
April 27, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28432501/high-scale-yield-of-nano-hydroxyapatite-through-combination-of-mechanical-activation-and-chemical-dispersion
#5
Xueling Gao, Chunchu Dai, Weiwei Liu, Yumei Liu, Ru Shen, Xiaotong Zheng, Ke Duan, Jie Weng, Shuxin Qu
The aim of this study is to develop a simple, convenient and effective approach to synthesize nano-sized hydroxyapatite (nano-HA) at high-scale yield. Nano-HA was wet synthesized in the presence or absence of alendronate sodium (ALN), one of bisphosphonates for anti-osteoporotic. Then aged and washed nano-HA precipitate was directly treated by mechanical activation combined with the chemical dispersion of ALN to prevent the agglomeration of nano-HA. ALN acted not only as a chemical dispersant but also as an orthopedic drug...
June 2017: Journal of Materials Science. Materials in Medicine
https://www.readbyqxmd.com/read/28427648/sonochemical-synthesis-characterization-and-effects-of-temperature-power-ultrasound-and-reaction-time-on-the-morphological-properties-of-two-new-nanostructured-mercury-ii-coordination-supramolecule-compounds
#6
Payam Hayati, Ali Reza Rezvani, Ali Morsali, Daniel Ruiz Molina, Samira Geravand, Salvio Suarez-Garcia, Miguel Angel Moreno Villaecija, S García-Granda, Rafael Mendoza-Meroño, Pascal Retailleau
Two new mercury(II) coordination supramolecular compounds (CSCs) (1D and 0D), [Hg(L)(I)2]n (1) and [Hg2(L')2(SCN)2]·2H2O (2) (L=2-amino-4-methylpyridine and L'=2,6-pyridinedicarboxlic acid), have been synthesized under different experimental conditions. Micrometric crystals (bulk) or nano-sized materials have been obtained depending on using the branch tube method or sonochemical irradiation. All materials have been characterized by field emission scanning electron microscope (FESEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD) and FT-IR spectroscopy...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28424589/the-calcium-channel-c-terminal-and-synaptic-vesicle-tethering-analysis-by-immuno-nanogold-localization
#7
Robert H C Chen, Qi Li, Christine A Snidal, Sabiha R Gardezi, Elise F Stanley
At chemical synapses the incoming action potential triggers the influx of Ca(2+) through voltage-sensitive calcium channels (CaVs, typically CaV2.1 and 2.2) and the ions binds to sensors associated with docked, transmitter filled synaptic vesicles (SVs), triggering their fusion and discharge. The CaVs and docked SVs are located within the active zone (AZ) region of the synapse which faces a corresponding neurotransmitter receptor-rich region on the post-synaptic cell. Evidence that the fusion of a SV can be gated by Ca(2+) influx through a single CaV suggests that the channel and docked vesicle are linked by one or more molecular tethers (Stanley, 1993)...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28424491/understanding-the-ion-induced-elongation-of-silver-nanoparticles-embedded-in-silica
#8
Ovidio Peña-Rodríguez, Alejandro Prada, José Olivares, Alicia Oliver, Luis Rodríguez-Fernández, Héctor G Silva-Pereyra, Eduardo Bringa, José Manuel Perlado, Antonio Rivera
In this work we have studied the elongation of silver nanoparticles irradiated with 40 MeV Bromine ions by means of in situ optical measurements, transmission electron microscopy and molecular dynamics simulations. The localized surface plasmon resonance of silver nanoparticles has a strong dependence on the particle shape and size, which allowed us to obtain the geometrical parameters with remarkable accuracy by means of a fit of the optical spectra. Optical results have been compared with transmission electron microscopy images and molecular dynamics simulations and the agreement is excellent in both cases...
April 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28423032/complete-study-demonstrating-the-absence-of-rhabdovirus-in-a-distinct-sf9-cell-line
#9
Yoshifumi Hashimoto, Daniel Macri, Indresh Srivastava, Clifton McPherson, Rachael Felberbaum, Penny Post, Manon Cox
A putative novel rhabdovirus (SfRV) was previously identified in a Spodoptera frugiperda cell line (Sf9 cells [ATCC CRL-1711 lot 58078522]) by next generation sequencing and extensive bioinformatic analysis. We performed an extensive analysis of our Sf9 cell bank (ATCC CRL-1711 lot 5814 [Sf9L5814]) to determine whether this virus was already present in cells obtained from ATCC in 1987. Inverse PCR of DNA isolated from Sf9 L5814 cellular DNA revealed integration of SfRV sequences in the cellular genome. RT-PCR of total RNA showed a deletion of 320 nucleotides in the SfRV RNA that includes the transcriptional motifs for genes X and L...
2017: PloS One
https://www.readbyqxmd.com/read/28416636/p53-dynamically-directs-tfiid-assembly-on-target-gene-promoters
#10
R A Coleman, Z Qiao, S K Singh, C S Peng, M Cianfrocco, Z Zhang, A Piasecka, H Aldeborgh, G Basishvili, W L Liu
p53 is a central regulator that turns on vast gene networks to maintain cellular integrity upon various stimuli. p53 activates transcription initiation in part by aiding recruitment of TFIID to the promoter. However, the precise means by which p53 dynamically interacts with TFIID to facilitate assembly on target gene promoters remains elusive. To address this key question, we have undertaken an integrated approach involving single molecule fluorescence microscopy, single particle cryo-electron microscopy, and biochemistry...
April 17, 2017: Molecular and Cellular Biology
https://www.readbyqxmd.com/read/28406968/the-sense-of-balance-in-humans-structural-features-of-otoconia-and-their-response-to-linear-acceleration
#11
Rüdiger Kniep, Dirk Zahn, Jana Wulfes, Leif Erik Walther
We explored the functional role of individual otoconia within the otolith system of mammalians responsible for the detection of linear accelerations and head tilts in relation to the gravity vector. Details of the inner structure and the shape of intact human and artificial otoconia were studied using environmental scanning electron microscopy (ESEM), including decalcification by ethylenediaminetetraacetic acid (EDTA) to discriminate local calcium carbonate density. Considerable differences between the rhombohedral faces of human and artificial otoconia already indicate that the inner architecture of otoconia is not consistent with the point group -3m...
2017: PloS One
https://www.readbyqxmd.com/read/28402623/growth-termination-and-multiple-nucleation-of-single-wall-carbon-nanotubes-evidenced-by-in-situ-transmission-electron-microscopy
#12
Lili Zhang, Maoshuai He, Thomas W Hansen, Jens Kling, Hua Jiang, Esko I Kauppinen, Annick Loiseau, Jakob B Wagner
In order to controllably grow single-wall carbon nanotubes (SWCNTs), it is required a better understanding of the growth processes and how they are influenced by external parameters such as catalyst and gaseous environment. Here, we present direct evidence of growth termination of individual SWCNTs and successive growth of additional SWCNTs on Co catalyst particles supported on MgO by means of environmental transmission electron microscopy (TEM). Such in situ observations reveal the plethora of solid carbon formations at the local scale while it is happening and thereby elucidate the multitude of configurations resulting from identical external synthesis conditions, which should be considered in the quest for controlled SWCNT growth...
April 12, 2017: ACS Nano
https://www.readbyqxmd.com/read/28398334/diffraction-data-of-core-shell-nanoparticles-from-an-x-ray-free-electron-laser
#13
Xuanxuan Li, Chun-Ya Chiu, Hsiang-Ju Wang, Stephan Kassemeyer, Sabine Botha, Robert L Shoeman, Robert M Lawrence, Christopher Kupitz, Richard Kirian, Daniel James, Dingjie Wang, Garrett Nelson, Marc Messerschmidt, Sébastien Boutet, Garth J Williams, Elisabeth Hartmann, Aliakbar Jafarpour, Lutz M Foucar, Anton Barty, Henry Chapman, Mengning Liang, Andreas Menzel, Fenglin Wang, Shibom Basu, Raimund Fromme, R Bruce Doak, Petra Fromme, Uwe Weierstall, Michael H Huang, John C H Spence, Ilme Schlichting, Brenda G Hogue, Haiguang Liu
X-ray free-electron lasers provide novel opportunities to conduct single particle analysis on nanoscale particles. Coherent diffractive imaging experiments were performed at the Linac Coherent Light Source (LCLS), SLAC National Laboratory, exposing single inorganic core-shell nanoparticles to femtosecond hard-X-ray pulses. Each facetted nanoparticle consisted of a crystalline gold core and a differently shaped palladium shell. Scattered intensities were observed up to about 7 nm resolution. Analysis of the scattering patterns revealed the size distribution of the samples, which is consistent with that obtained from direct real-space imaging by electron microscopy...
April 11, 2017: Scientific Data
https://www.readbyqxmd.com/read/28396859/electron-microscopy-structural-insights-into-cpap-oligomeric-behavior-a-plausible-assembly-process-of-a-supramolecular-scaffold-of-the-centrosome
#14
Ana L Alvarez-Cabrera, Sandra Delgado, David Gil-Carton, Gulnahar B Mortuza, Guillermo Montoya, Carlos O S Sorzano, Tang K Tang, Jose M Carazo
Centrosomal P4.1-associated protein (CPAP) is a cell cycle regulated protein fundamental for centrosome assembly and centriole elongation. In humans, the region between residues 897-1338 of CPAP mediates interactions with other proteins and includes a homodimerization domain. CPAP mutations cause primary autosomal recessive microcephaly and Seckel syndrome. Despite of the biological/clinical relevance of CPAP, its mechanistic behavior remains unclear and its C-terminus (the G-box/TCP domain) is the only part whose structure has been solved...
2017: Frontiers in Molecular Biosciences
https://www.readbyqxmd.com/read/28395483/preconditioning-of-the-ysz-nio-fuel-cell-anode-in-hydrogenous-atmospheres-containing-water-vapor
#15
Bogdan Vasyliv, Viktoriya Podhurska, Orest Ostash
The YSZ-NiO ceramics for solid oxide fuel cells (SOFCs) anode have been investigated. A series of specimens were singly reduced in a hydrogenous atmosphere (Ar-5 vol% H2 mixture) at 600 °C under the pressure of 0.15 MPa or subjected to 'reduction in the mixture-oxidation in air' (redox) cycling at 600 °C. The YSZ-Ni cermets formed in both treatment conditions were then aged in 'water vapor in Ar-5 vol% H2 mixture' atmosphere at 600 °C under the pressure of 0.15 MPa. Additionally, the behaviour of the as-received material in this atmosphere was studied...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28395348/exposure-assessment-in-a-single-walled-carbon-nanotube-primary-manufacturer
#16
Serge Kouassi, Cyril Catto, Claude Ostiguy, Gilles L'Espérance, Jens Kroeger, Maximilien Debia
Objectives: This study was aimed at documenting and characterizing occupational exposure to single-walled carbon nanotubes (SWCNTs) generated in a primary manufacturing plant. It also compared various strategies of exposure monitoring. Methods: A 6-day measurement protocol was scheduled (D1-D6) including both (i) quasi-personal monitoring with an array of direct reading instruments (DRIs) and (ii) offline electron microscopy analyses of surface and breathing zone filter-based samples...
March 1, 2017: Annals of Work Exposures and Health
https://www.readbyqxmd.com/read/28394313/structure-of-the-mycobacterial-esx-5-type-vii-secretion-system-membrane-complex-by-single-particle-analysis
#17
Katherine S H Beckham, Luciano Ciccarelli, Catalin M Bunduc, Haydyn D T Mertens, Roy Ummels, Wolfgang Lugmayr, Julia Mayr, Mandy Rettel, Mikhail M Savitski, Dmitri I Svergun, Wilbert Bitter, Matthias Wilmanns, Thomas C Marlovits, Annabel H A Parret, Edith N G Houben
Mycobacteria are characterized by their impermeable outer membrane, which is rich in mycolic acids(1). To transport substrates across this complex cell envelope, mycobacteria rely on type VII (also known as ESX) secretion systems(2). In Mycobacterium tuberculosis, these ESX systems are essential for growth and full virulence and therefore represent an attractive target for anti-tuberculosis drugs(3). However, the molecular details underlying type VII secretion are largely unknown, due to a lack of structural information...
April 10, 2017: Nature Microbiology
https://www.readbyqxmd.com/read/28393837/cryo-em-structures-of-mers-cov-and-sars-cov-spike-glycoproteins-reveal-the-dynamic-receptor-binding-domains
#18
Yuan Yuan, Duanfang Cao, Yanfang Zhang, Jun Ma, Jianxun Qi, Qihui Wang, Guangwen Lu, Ying Wu, Jinghua Yan, Yi Shi, Xinzheng Zhang, George F Gao
The envelope spike (S) proteins of MERS-CoV and SARS-CoV determine the virus host tropism and entry into host cells, and constitute a promising target for the development of prophylactics and therapeutics. Here, we present high-resolution structures of the trimeric MERS-CoV and SARS-CoV S proteins in its pre-fusion conformation by single particle cryo-electron microscopy. The overall structures resemble that from other coronaviruses including HKU1, MHV and NL63 reported recently, with the exception of the receptor binding domain (RBD)...
April 10, 2017: Nature Communications
https://www.readbyqxmd.com/read/28392961/preparation-and-characterization-of-suvarna-bhasma-parada-marit
#19
Kapil Thakur, Ramacharya Gudi, Mahesh Vahalia, Shekhar Shitut, Shailesh Nadkarni
OBJECTIVES: The goal of this study was to characterize Suvarna Bhasma Parada Marit by using the Ayurvedic test parameters, physico-chemical tests, and various instrumentation techniques. METHODS: Suvarna Bhasma, an Ayurvedic formulation manufactured as per Bharat Bhaishajya Ratnakar 5/8357 (BBR), has been studied using various instrumentation techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), laser particle size distribution (PSD) analysis, fourier transform infrared spectroscopy (FT-IR), and atomic absorption spectroscopy (AAS), and physico-chemical parameters, such as the loss on drying (LOD), loss on ignition (LOI), and acid insoluble Ash (AIA) were determined...
March 2017: Journal of Pharmacopuncture
https://www.readbyqxmd.com/read/28386480/comparative-study-on-the-mechanical-and-microstructural-characterisation-of-aa-7075-nano-and-hybrid-nanocomposites-produced-by-stir-and-squeeze-casting
#20
C Kannan, R Ramanujam
In this research work, a comparative evaluation on the mechanical and microstructural characteristics of aluminium based single and hybrid reinforced nanocomposites was carried out. The manufacture of a single reinforced nanocomposite was conducted with the distribution of 2 wt.% nano alumina particles (avg. particle size 30-50 nm) in the molten aluminium alloy of grade AA 7075; while the hybrid reinforced nanocomposites were produced with of 4 wt.% silicon carbide (avg. particle size 5-10 µm) and 2 wt...
July 2017: Journal of Advanced Research
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