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https://www.readbyqxmd.com/read/28340527/synthesis-and-adsorption-properties-of-4-vinylpyridine-and-styrene-copolymer-in-situ-immobilized-on-silica-surface
#1
E S Yanovska, L O Vretik, O A Nikolaeva, Y Polonska, D Sternik, O Yu Kichkiruk
Copolymer of 4-vinylpyridine with styrene was in situ immobilized on silica gel surface via the heterogeneous radical polymerization. Anchorage of the copolymer on the surface layer was confirmed by IR spectroscopy. The quantity of copolymer on the silica gel surface was evaluated as 25.73 wt.% by TG and DSC-MS analysis. "Islet" location of polymer layer on the silica surface was confirmed by the scanning electron microscopy. A high adsorption activity of silica gel with immobilized copolymer towards microquantitatives of Cu(II), Cd(II), Pb(II), Fe(III), and Ni(II) ions in steady state conditions as well as of Ni(II) ions in dynamic regime was found...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28340521/stable-and-controllable-synthesis-of-silver-nanowires-for-transparent-conducting-film
#2
Bitao Liu, Hengqing Yan, Shanyong Chen, Youwei Guan, Guoguo Wu, Rong Jin, Lu Li
Silver nanowires without particles are synthesized by a solvothermal method at temperature 150 °C. Silver nanowires are prepared via a reducing agent of glycerol and a capping agent of polyvinylpyrrolidone (M w  ≈ 1,300,000). Both of them can improve the purity of the as-prepared silver nanowires. With controllable shapes and sizes, silver nanowires are grown continuously up to 10-20 μm in length with 40-50 nm in diameter. To improve the yield of silver nanowires, the different concentrations of AgNO3 synthesis silver nanowires are discussed...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28340512/activation-mechanisms-of-%C3%AE-v%C3%AE-3-integrin-by-binding-to-fibronectin-a-computational-study
#3
Lingyun Wang, Di Pan, Qi Yan, Yuhua Song
Integrin αVβ3 plays an important role in regulating cellular activities and in human diseases. Although the structure of αVβ3 has been studied by crystallography and electron microscopy, the detailed activation mechanism of integrin αVβ3 induced by fibronectin (Fn) remains unclear. In this study, we investigated the conformational and dynamical motion changes of Mn(2+) -bound integrin αVβ3 by binding to Fn with molecular dynamics simulations. Results showed that Fn binding to integrin αVβ3 caused the changes of the conformational flexibility of αVβ3 domains, the essential mode of motion for the domains of αV subunit and β3 subunit and the degrees of correlated motion of residues between the domains of αV subunit and β3 subunit of integrin αVβ3...
March 24, 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28340394/assessment-of-engineered-surfaces-roughness-by-high-resolution-3d-sem-photogrammetry
#4
L C Gontard, J D López-Castro, L González-Rovira, J M Vázquez-Martínez, F M Varela-Feria, M Marcos, J J Calvino
We describe a methodology to obtain three-dimensional models of engineered surfaces using scanning electron microscopy and multi-view photogrammetry (3DSEM). For the reconstruction of the 3D models of the surfaces we used freeware available in the cloud. The method was applied to study the surface roughness of metallic samples patterned with parallel grooves by means of laser. The results are compared with measurements obtained using stylus profilometry (PR) and SEM stereo-photogrammetry (SP). The application of 3DSEM is more time demanding than PR or SP, but it provides a more accurate representation of the surfaces...
March 7, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28340349/structure-reveals-mechanisms-of-viral-suppressors-that-intercept-a-crispr-rna-guided-surveillance-complex
#5
Saikat Chowdhury, Joshua Carter, MaryClare F Rollins, Sarah M Golden, Ryan N Jackson, Connor Hoffmann, Lyn'Al Nosaka, Joseph Bondy-Denomy, Karen L Maxwell, Alan R Davidson, Elizabeth R Fischer, Gabriel C Lander, Blake Wiedenheft
Genetic conflict between viruses and their hosts drives evolution and genetic innovation. Prokaryotes evolved CRISPR-mediated adaptive immune systems for protection from viral infection, and viruses have evolved diverse anti-CRISPR (Acr) proteins that subvert these immune systems. The adaptive immune system in Pseudomonas aeruginosa (type I-F) relies on a 350 kDa CRISPR RNA (crRNA)-guided surveillance complex (Csy complex) to bind foreign DNA and recruit a trans-acting nuclease for target degradation. Here, we report the cryo-electron microscopy (cryo-EM) structure of the Csy complex bound to two different Acr proteins, AcrF1 and AcrF2, at an average resolution of 3...
March 23, 2017: Cell
https://www.readbyqxmd.com/read/28340337/structural-basis-of-rna-polymerase-i-transcription-initiation
#6
Christoph Engel, Tobias Gubbey, Simon Neyer, Sarah Sainsbury, Christiane Oberthuer, Carlo Baejen, Carrie Bernecky, Patrick Cramer
Transcription initiation at the ribosomal RNA promoter requires RNA polymerase (Pol) I and the initiation factors Rrn3 and core factor (CF). Here, we combine X-ray crystallography and cryo-electron microscopy (cryo-EM) to obtain a molecular model for basal Pol I initiation. The three-subunit CF binds upstream promoter DNA, docks to the Pol I-Rrn3 complex, and loads DNA into the expanded active center cleft of the polymerase. DNA unwinding between the Pol I protrusion and clamp domains enables cleft contraction, resulting in an active Pol I conformation and RNA synthesis...
March 23, 2017: Cell
https://www.readbyqxmd.com/read/28340334/advances-in-phase-plate-cryo-em-imaging-of-dna-and-nucleosomes
#7
Eugene Y D Chua, Sara Sandin
Contrast in electron cryo-microscopy (cryo-EM) is limited by the weak phase and radiation sensitive nature of biologic samples embedded in vitrified ice. We have recently shown that a new contrast enhancement technique utilizing the Volta phase plate can be combined with single particle analysis to determine the structure of a small chromatin complex, the nucleosome core particle, at near-atomic resolution. Here, we discuss advantages and limitations of the technique in terms of data collection, particle detection, and visualization of individual DNA molecules and higher-order chromatin structure...
February 7, 2017: Nucleus
https://www.readbyqxmd.com/read/28340297/atomic-scale-snapshots-of-the-formation-and-growth-of-hollow-ptni-c-nanocatalysts
#8
Raphael Chattot, Tristan Asset, Jakub Drnec, Pierre Bordet, Jaysen Nelayah, Laetitia Dubau, Frédéric Maillard
Determining the formation and growth mechanism of bimetallic nanoparticles (NPs) with atomic detail is fundamental to synthesize efficient 'catalysts by design'. However, the understanding of the elementary steps, which take place during their synthesis remains elusive. Herein, we have exploited scanning transmission electron microscopy coupled to energy dispersive X-ray spectroscopy, operando wide angle and small angle X-ray scattering and electrochemistry to unveil the formation and growth mechanism of hollow PtNi/C NPs...
March 24, 2017: Nano Letters
https://www.readbyqxmd.com/read/28340293/functional-paper-based-platform-for-rapid-capture-and-detection-of-ceo2-nanoparticles
#9
Ali Othman, Daniel Andreescu, Dinusha P Karunaratne, Suryadevara V Babu, Silvana Andreescu
Development of systems for capture, sequestration and tracking of nanoparticles (NPs) is becoming a significant focus in many aspects of nanotechnology and environmental research. These systems enable a broad range of applications for evaluating concentration, distribution and effects of NPs for environmental, clinical, epidemiological and occupational exposure studies. Herein, we describe the first example of a ligand-graft multifunctional platform for capture and detection of cerium oxide (CeO2 or ceria) NPs...
March 24, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28340187/biofilm-adherence-and-hydrophobicity-as-virulence-factors-in-malassezia-furfur
#10
Letizia Angiolella, Claudia Leone, Florencia Rojas, Javier Mussin, María de Los Angeles Sosa, Gustavo Giusiano
Malassezia species are natural inhabitants of the healthy skin. However, under certain conditions, they may cause or exacerbate several skin diseases. The ability of this fungus to colonize or infect is determined by complex interactions between the fungal cell and its virulence factors. This study aims to evaluate "in vitro" the hydrophobicity levels, the adherence on a plastic surface and the biofilm formation of 16 clinical isolates of Malassezia furfur. Cellular surface hydrophobicity (CSH) levels were determined by two-phase system...
March 9, 2017: Medical Mycology: Official Publication of the International Society for Human and Animal Mycology
https://www.readbyqxmd.com/read/28339939/developmental-morphology-study-on-the-stomach-of-african-ostrich-chicks
#11
J X Wang, P Li, X T Zhang, L X Ye
This study investigates the developmental morphology changes on the proventriculus and gizzard of African ostrich chicks using gross anatomy, and light and transmission electronic microscopy. The body weight; the weight of the proventriculus and gizzard; the thickness of simple tubular glands, muscularis mucosae, compound tubular glands, and muscular layer of the proventriculus; and the thickness of the gizzard glands and muscularis mucosae were measured on postnatal d one, 45, 90, and 334. Under transmission electronic microscopy, the oxynticopeptic cells, mucous cells, and endocrine cells were observed in the proventriculus on postnatal d one, 45, and 90...
March 2, 2017: Poultry Science
https://www.readbyqxmd.com/read/28339926/study-on-the-expression-of-human-lysozyme-in-oviduct-bioreactor-mediated-by-recombinant-avian-adeno-associated-virus1
#12
A P Wang, Y J Wang, S Wu, W Y Zuo, C M Guo, W M Hong, S Y Zhu
Due to its antimicrobial properties and low toxicity, human lysozyme (hLYZ) has broad application in the medical field and as a preservative used by the food industry. However, limited availability hinders its widespread use. Hence, we constructed a recombinant avian adeno-associated virus (rAAAV) that would specifically express hLYZ in the chicken oviduct and harvested hLYZ from the egg whites of laying hens. The oviduct-specific human lysozyme expression cassette flanked by avian adeno-associated virus (AAAV) inverted terminal repeats (ITRs) was subcloned into the modified baculovirus transfer vector pFBX, and then the recombinant baculovirus rBac-ITRLYZ was generated...
March 2, 2017: Poultry Science
https://www.readbyqxmd.com/read/28339813/microstructural-observation-of-fuel-cell-catalyst-inks-by-cryo-sem-and-cryo-tem
#13
Junichi Shimanuki, Shinichi Takahashi, Hajime Tohma, Atsushi Ohma, Ayumi Ishihara, Yoshiko Ito, Yuri Nishino, Atsuo Miyazawa
In order to improve the electricity generation performance of fuel cell electric vehicles, it is necessary to optimize the microstructure of the catalyst layer of a polymer electrolyte fuel cell. The catalyst layer is formed by a wet coating process using catalyst inks. Therefore, it is very important to observe the microstructure of the catalyst ink. In this study, the morphology of carbon-supported platinum (Pt/C) particles in catalyst inks with a different solvent composition was investigated by cryogenic scanning electron microscopy (cryo-SEM)...
February 9, 2017: Microscopy
https://www.readbyqxmd.com/read/28339777/support-system-for-fine-focusing-and-astigmatism-correction-using-an-auditory-signal-in-scanning-electron-microscopy
#14
Eisaku Oho, Kazuhiko Suzuki, Sadao Yamazaki
The current study describes a new support system for fine focusing and near-perfect astigmatism correction for scanning electron microscopy (SEM). The signal-to-noise ratio of a series of SEM images obtained from fast scan rates (TV scan) was adopted as a new metric for evaluating focus. Measured signal-to-noise ratio values were converted to an acoustic signal (sound wave frequency) using digital image processing techniques, enabling the SEM user to evaluate image focus using the auditory modality. Accurate focusing and correcting astigmatism in general-purpose SEM is traditionally time-consuming and difficult...
February 24, 2017: Microscopy
https://www.readbyqxmd.com/read/28339715/determination-of-pre-cecal-phosphorus-digestibility-of-inorganic-phosphates-and-bone-meal-products-in-broilers
#15
J van Harn, J W Spek, C A van Vuure, M M van Krimpen
A broiler study was performed to determine the pre-cecal phosphorus (P) digestibility of 5 P sources, 3 from animal (Delfos, Calfos, and porcine bone meal) and 2 of inorganic (monocalcium phosphate [MCP] and dicalcium phosphate [DCP]) origin. Delfos is processed from bones resulting in a dicalcium phosphate product, and Calfos is processed from bones in which part of the gelatin is removed but in which the hydroxy-apatite matrix is preserved. During the first 14 d, birds were housed in floor pens bedded with wood shavings and received a commercial starter diet...
February 22, 2017: Poultry Science
https://www.readbyqxmd.com/read/28339639/comparative-structural-study-of-the-zona-radiata-of-the-eggs-of-three-gobiobotia-cyprinidae-teleostei-endemic-korean-freshwaters
#16
Woong Sun Choi, Jae Goo Kim, Jong Young Park
The genus Gobiobotia in Korea has only three species and all are endemic benthic freshwater fishes. Their oocytes were observed by light microscopy, scanning electron microscopy and transmission electron microscopy to investigate the characteristics of the zona radiata (ZR), a non-cellular envelope, which surrounds the egg. Various developmental cells appeared during the spawning season. During the yolk vesicles stage, which yolk vesicles are spherically developed in periphery of the cytoplasm and gradually increase in its number and size, the ZR becomes visible between its follicular layer and ooplasm...
February 15, 2017: Microscopy
https://www.readbyqxmd.com/read/28339603/optimization-of-stem-imaging-conditions-for-cryo-tomography
#17
Kazuhiro Aoyama, Kotaro Nagano, Kaoru Mitsuoka
For three-dimensional analysis of cryo-specimens using tomography at low and medium magnifications, the use of STEM images has some important advantages over TEM. A clear understanding of the electron dose in STEM is essential for optimized cryo-microscopy so a dose estimation technique for STEM imaging has been developed. The STEM convergence angle was shown to have a large impact on the image quality, in particular on the signal-to-noise ratio in the acquired images. Importantly, there is a clear trade-off between good STEM spatial resolution in the images with a large convergence angle and the signal-to-noise ratio, which is improved by reducing the convergence angle as much as possible...
February 9, 2017: Microscopy
https://www.readbyqxmd.com/read/28339348/geological-occurrence-mineralogical-characterization-and-risk-assessment-of-potentially-carcinogenic-erionite-in-italy
#18
Matteo Giordani, Michele Mattioli, Paolo Ballirano, Alessandro Pacella, Marco Cenni, Matteo Boscardin, Laura Valentini
Erionite is a zeolite representing a well-known health hazard. In fact, exposure of humans to its fibers has been unequivocally associated with occurrence of malignant mesothelioma. For this reason, a multi-methodological approach, based upon field investigation, morphological characterization, scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS) chemical analysis, and structure refinement through X-ray powder diffraction (XRPD), was applied to different samples of potentially carcinogenic erionite from Northern Italy...
2017: Journal of Toxicology and Environmental Health. Part B, Critical Reviews
https://www.readbyqxmd.com/read/28339234/influence-of-domain-walls-in-the-incommensurate-charge-density-wave-state-of-cu-intercalated-1t-tise_-2
#19
Shichao Yan, Davide Iaia, Emilia Morosan, Eduardo Fradkin, Peter Abbamonte, Vidya Madhavan
We report a low-temperature scanning tunneling microscopy study of the charge density wave (CDW) order in 1T-TiSe_{2} and Cu_{0.08}TiSe_{2}. In pristine 1T-TiSe_{2} we observe a long-range coherent commensurate CDW (CCDW) order. In contrast, Cu_{0.08}TiSe_{2} displays an incommensurate CDW (ICDW) phase with localized CCDW domains separated by domain walls. Density of states measurements indicate that the domain walls host an extra population of fermions near the Fermi level which may play a role in the emergence of superconductivity in this system...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28339183/tunable-porosity-of-crosslinked-polyhedral-oligomeric-silsesquioxane-poss-supports-for-palladium-catalyzed-aerobic-alcohol-oxidation-in-water
#20
Preeyanuch Sangtrirutnugul, Thanawat Chaiprasert, Warodom Hunsiri, Thanudkit Jitjaroendee, Patsaya Songkhum, Kritapas Laohhasurayotin, Tanakorn Osotchan, Vuthichai Ervithayasuporn
Polyhedral oligomeric silsesquioxane (POSS)-based materials, poly-POSS-Tn [n = 8 (1), 10 (2), 12 (3), and mix (4)], were prepared in high yields via free radical polymerization of corresponding pure forms of methacrylate-functionalized POSS monomers, MMA-POSS-Tn (n = 8, 10, 12), and the mixture form, MMA-POSS-Tmix. Powder X-ray diffraction (XRD) spectra and BET analysis indicate that 1-4 are amorphous materials with high surface areas (683-839 m2•g-1). The surface areas and total pore volumes follow the trend: poly-POSS-T12 > poly-POSS-T10 > poly-POSS-Tmix > poly-POSS-T8...
March 24, 2017: ACS Applied Materials & Interfaces
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