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single particle analysis

Anders Lundgren, Björn Agnarsson, Ronald Zirbs, Vladimir P Zhdanov, Erik Reimhult, Fredrik Höök
Emerging biomedical applications such as molecular imaging and drug delivery often require directed binding of nanoparticles to cell-membrane receptors. The specific apparent affinity of such ligand-functionalized particles is size-dependent, an observation so far solely attributed to multivalent receptor-ligand interaction. We question the universality of this explanation by demonstrating that the binding kinetics also depends on weak, attractive colloidal-type interaction between nanoparticles and a lipid membrane...
October 26, 2016: ACS Nano
Zhongbo Zhou, Yiting Tan, Yeyuan Roger Xiao, David C Stuckey
The distribution, composition and morphological structure of sub-visible particles and colloids (0.01-10 µm) in the supernatant of a lab-scale submerged anaerobic membrane reactor (SAnMBR), and their role in membrane fouling, was investigated. Photometric analysis showed that the supernatant and membrane foulants were dominated by particles and colloids (0.45-10 µm), which accounted for over 90% of the total organics (proteins and polysaccharides). Excitation-emission matrix (EEM) fluorescence spectra and monosaccharide analysis showed that these particles and colloids were rich in fluorescent proteins, rhamnose, ribose and arabinose, all of which could be related to cellular and extracellular substances...
October 26, 2016: Environmental Science & Technology
Lei Liu, Cui-E Hu, Mei Tang, Xiang-Rong Chen, Ling-Cang Cai
The low-lying isomers of cationic water cluster (H2O)6(+) have been globally explored by using particle swarm optimization algorithm in conjunction with quantum chemical calculations. Compared with previous results, our searching method covers a wide range of structural isomers of (H2O)6(+) and therefore turns out to be more effective. With these local minima, geometry optimization and vibrational analysis are performed for the most interesting clusters at second-order Møller-Plesset (MP2)/aug-cc-pVDZ level, and their energies are further refined at MP2/aug-cc-pVTZ and coupled-cluster theory with single, double, and perturbative triple excitations/aug-cc-pVDZ level...
October 21, 2016: Journal of Chemical Physics
Payam Hayati, Ali Reza Rezvani, Ali Morsali, Pascal Retailleau, S García-Granda
Nanoparticles of two new coordination compounds, [Hg2(L)2(Br)4]n (1) and [Hg(L')(SCN)2] (2), (L=2-amino-4-methylpyridine, L'=2,6-pyridinedicarboxlic acid), have been synthesized by use of a sonochemical process and characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy(FESEM), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR) spectroscopy and elemental analyses. The single crystal X-ray data of compounds 1 and 2 imply that the Hg(II) ions are four and five coordinated, respectively...
January 2017: Ultrasonics Sonochemistry
Payam Hayati, Ali Reza Rezvani, Ali Morsali, Pascal Retailleau
Two new potassium coordination supramolecular compounds (2D and 1D), [K(H3L)(H2L)(H2O)]n·H2O (1) and [K(H2L')(HL')(H2O)2]·H2O (2), (L=1,3,5-tricarboxylic acid, L'=2,6-pyridinedicarboxylic 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 microscopy (FE-SEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), FT-IR spectroscopy and elemental analyses...
January 2017: Ultrasonics Sonochemistry
Payam Hayati, AliReza Rezvani, Ali Morsali, Pascal Retailleau, Roberto Centore
Nanoparticles of two new 0D, lead(II) coordination supramolecular compounds, [Pb(L)2(I)2] (1) and [Pb(L)(L(/))(H2O)]·3H2O (2), (L=1,10-phenanthroline monohydrate, L(/)=2,6-pyridinedicarboxlic acid), have been synthesized by a sonochemical process and characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRPD), FT-IR spectroscopy and elemental analyses. The single crystal X-ray data of compounds show that the Pb ion is six coordinated in both 1 and 2...
September 7, 2016: Ultrasonics Sonochemistry
Luna Rahman, Dongmei Wu, Michael Johnston, Andrew William, Sabina Halappanavar
Titanium dioxide nanoparticles (TiO2NPs) induce lung inflammation in experimental animals. In this study, we conducted a comprehensive toxicogenomic analysis of lung responses in mice exposed to six individual TiO2NPs exhibiting different sizes (8, 20 and 300nm), crystalline structure (anatase, rutile or anatase/rutile) and surface modifications (hydrophobic or hydrophilic) to investigate whether the mechanisms leading to TiO2NP-induced lung inflammation are property specific. A detailed histopathological analysis was conducted to investigate the long-term disease implications of acute exposure to TiO2NPs...
October 19, 2016: Mutagenesis
Jooyeon Jeong, Kwangryul Baek, Henning Kirst, Anastasios Melis, EonSeon Jin
The Chlamydomonas reinhardtii truncated light-harvesting antenna 4 (tla4) DNA transposon mutant has a pale green phenotype, a lower chlorophyll (Chl) per cell and a higher Chl a/b ratio in comparison with the wild type. It required a higher light intensity for the saturation of photosynthesis and displayed a greater per chlorophyll light-saturated rate of oxygen evolution than the wild type. The Chl antenna size of the photosystems in the tla4 mutant was only about 65% of that measured in the wild type. Molecular genetic analysis revealed that a single plasmid DNA insertion disrupted two genes on chromosome 11 of the mutant...
October 17, 2016: Biochimica et Biophysica Acta
Stephen R Sanchez, Sergei M Bachilo, Yara Kadria-Vili, Ching-Wei Lin, R Bruce Weisman
A new method based on variance spectroscopy has enabled the determination of absolute absorption cross sections for the first electronic transition of twelve (n,m) structural species of semiconducting single-walled carbon nanotubes (SWCNTs). Spectrally resolved measurements of fluorescence variance in dilute bulk samples provided particle number concentrations of specific SWCNT species. These values were converted to carbon concentrations and correlated with resonant components in the absorbance spectrum to deduce (n,m)-specific absorption cross sections (absorptivities) for nanotubes ranging in diameter from 0...
October 19, 2016: Nano Letters
K N Sathish Yadav, Dmitry A Semchonok, Lukáš Nosek, Roman Kouřil, Geoffrey Fucile, Egbert J Boekema, Lutz A Eichacker
Photosystem I (PSI) is a pigment-protein complex required for the light-dependent reactions of photosynthesis and participates in light-harvesting and redox-driven chloroplast metabolism. Assembly of PSI into supercomplexes with light harvesting complex (LHC) II, cytochrome b6f (Cytb6f) or NAD(P)H dehydrogenase complex (NDH) has been proposed as a means for regulating photosynthesis. However, structural details about the binding positions in plant PSI are lacking. We analyzed large data sets of electron microscopy single particle projections of supercomplexes obtained from the stroma membrane of Arabidopsis thaliana...
October 15, 2016: Biochimica et Biophysica Acta
Christopher J Benjamin, Kyle J Wright, Scott C Bolton, Seok-Hee Hyun, Kyle Krynski, Mahima Grover, Guimei Yu, Fei Guo, Tamara L Kinzer-Ursem, Wen Jiang, David H Thompson
We report the fabrication of transmission electron microscopy (TEM) grids bearing graphene oxide (GO) sheets that have been modified with N(α), N(α)-dicarboxymethyllysine (NTA) and deactivating agents to block non-selective binding between GO-NTA sheets and non-target proteins. The resulting GO-NTA-coated grids with these improved antifouling properties were then used to isolate His6-T7 bacteriophage and His6-GroEL directly from cell lysates. To demonstrate the utility and simplified workflow enabled by these grids, we performed cryo-electron microscopy (cryo-EM) of His6-GroEL obtained from clarified E...
October 17, 2016: Scientific Reports
Gongbo Chen, Wenyi Zhang, Shanshan Li, Yongming Zhang, Gail Williams, Rachel Huxley, Hongyan Ren, Wei Cao, Yuming Guo
BACKGROUND: There is good evidence that air pollution is a risk factor for adverse respiratory and vascular health outcomes. However, data are limited as to whether ambient fine particles contribute to the transmission of influenza and if so, how the association is modified by weather conditions. OBJECTIVES: We examined the relationship between ambient PM2.5 and influenza incidence at the national level in China and explored the associations at different temperatures...
October 10, 2016: Environment International
Mina Yasaki, Yasushi Hirano, Hiroyuki Uga, Kaoru Hanada, Tamaki Uehara-Ichiki, Takeshi Toda, Hiromitsu Furuya, Shin-Ichi Fuji
An isometric virus was isolated from a cultivated Adonis plant (A. ramosa). The purified virus particle is 28 nm in diameter and is composed of a single coat protein and a single RNA genome of 3,991 nucleotides. Sequence analysis showed that the virus is closely related to carnation mottle virus. The virus was used to mechanically infect healthy A. ramosa plants, resulting in mosaic and leaf curl symptoms; however, attempts to inoculate carnation plants did not result in infection. We propose the virus as a new carmovirus and have named it adonis mosaic virus (AdMV)...
October 13, 2016: Archives of Virology
Pourya Shahpoury, Gerhard Lammel, Alexandre Albinet, Aysun Sofuoglu, Yetkin Dumanoglu, Sait C Sofuoglu, Zdenek Wagner, Vladimir Zdimal
A model for gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs) was evaluated using poly-parameter linear free energy relationships (ppLFERs) following a multiphase aerosol scenario. The model differentiates between various organic (i.e. liquid water soluble (WS)/organic soluble (OS) organic matter (OM) and solid/semi-solid organic polymers) and inorganic phases of the particulate matter (PM). Dimethyl sulfoxide and polyurethane were assigned as surrogates to simulate absorption into the abovementioned organic phases, respectively, whereas soot, ammonium sulfate, and ammonium chloride simulated adsorption processes onto PM...
October 13, 2016: Environmental Science & Technology
Igor Orlov, Alexander G Myasnikov, Leonid Andronov, S Kundhavai Natchiar, Heena Khatter, Brice Beinsteiner, Jean-François Ménétret, Isabelle Hazemann, Kareem Mohideen, Karima Tazibt, Rachel Tabaroni, Hanna Kratzat, Nadia Djabeur, Tatiana Bruxelles, Finaritra Raivoniaina, Lorenza di Pompeo, Morgan Torchy, Isabelle Billas, Alexandre Urzhumtsev, Bruno P Klaholz
After gradually moving away from preparation methods prone to artefacts such as plastic embedding and negative staining for cell sections and single particles, the field of cryo electron microscopy is now heading off at unprecedented speed towards high-resolution analysis of biological objects of various sizes. This "revolution in resolution" is happening largely thanks to new developments of new-generation cameras used for recording the images in the cryo electron microscope which have much increased sensitivity being based on CMOS devices...
October 12, 2016: Biology of the Cell
J Vargas, E Franken, C O S Sorzano, J Gomez-Blanco, R Schoenmakers, A J Koster, J M Carazo
Automatic or semiautomatic data collection approaches on a transmission electron microscope (TEM) for Single Particle Analysis, capable of acquiring large datasets composed of only high quality images, are of great importance to obtain 3D density maps with the highest resolution possible. Typically, this task is performed by an experienced microscopist, who manually decides to keep or discard images according to subjective criteria. Therefore, this methodology is slow, intensive in human work and subjective...
October 8, 2016: Journal of Structural Biology
F G Mitri
The analysis using the partial-wave series expansion (PWSE) method in spherical coordinates is extended to evaluate the acoustic radiation force experienced by rigid oblate and prolate spheroids centered on the axis of wave propagation of high-order Bessel vortex beams composed of progressive, standing and quasi-standing waves, respectively. A coupled system of linear equations is derived after applying the Neumann boundary condition for an immovable surface in a non-viscous fluid, and solved numerically by matrix inversion after performing a single numerical integration procedure...
September 30, 2016: Ultrasonics
Juyeong Kim, Matthew R Jones, Zihao Ou, Qian Chen
We use liquid phase transmission electron microscopy (LP-TEM) to characterize the structure and dynamics of a solution-phase superlattice assembled from gold nanoprisms at the single particle level. The lamellar structure of the superlattice, determined by a balance of inter-prism interactions, is maintained and resolved under low-dose imaging conditions typically reserved for biomolecular imaging. In this dose range, we capture dynamic structural changes in the superlattice in real time, where contraction and smaller steady-state lattice constants are observed at higher electron dose rates...
October 10, 2016: ACS Nano
Vijay Sundaram, Kasiviswanathan Muthukumarappan, Stephen Gent
Lignocellulosic feedstocks corn stover, prairie cord grass, and switchgrass were subjected to ammonia fiber expansion (AFEX™) pretreatment and densified using extrusion pelleting and ComPAKco densification technique. The effects of AFEX™ pretreatment and densification were studied on the fast pyrolysis product yields. Feedstocks were milled in a hammer mill using three different screen sizes (2, 4, and 8 mm) and were subjected to AFEX™ pretreatment. The untreated and AFEX™-pretreated feedstocks were moisture adjusted at three levels (5, 10, and 15 % wb) and were extruded using a lab-scale single screw extruder...
October 8, 2016: Applied Biochemistry and Biotechnology
Andrea Käppler, Dieter Fischer, Sonja Oberbeckmann, Gerald Schernewski, Matthias Labrenz, Klaus-Jochen Eichhorn, Brigitte Voit
The contamination of aquatic ecosystems with microplastics has recently been reported through many studies, and negative impacts on the aquatic biota have been described. For the chemical identification of microplastics, mainly Fourier transform infrared (FTIR) and Raman spectroscopy are used. But up to now, a critical comparison and validation of both spectroscopic methods with respect to microplastics analysis is missing. To close this knowledge gap, we investigated environmental samples by both Raman and FTIR spectroscopy...
October 8, 2016: Analytical and Bioanalytical Chemistry
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