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https://www.readbyqxmd.com/read/29054043/systematic-approaches-for-targeting-an-atom-probe-tomography-sample-fabricated-in-a-thin-tem-specimen-correlative-structural-chemical-and-3-d-reconstruction-analyses
#1
Sung-Il Baik, Dieter Isheim, David N Seidman
Atom-probe tomography (APT) is a unique analysis tool that enables true three-dimensional (3-D) analyses with sub-nano scale spatial resolution. Recent implementations of the local-electrode atom-probe (LEAP) tomograph with ultraviolet laser pulsing have significantly expanded the research applications of APT. The small field-of-view of a needle-shaped specimen with a less than 100 nm diam. is, however, a major limitation for analyzing materials. The systematic approaches for site-specific targeting of an APT nanotip in a transmission electron microscope (TEM) of a thin sample are introduced to solve the geometrical limitations of a sharpened APT nanotip...
October 12, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/29054021/qprtase-modified-n-doped-carbon-quantum-dots-a-fluorescent-bioprobe-for-selective-detection-of-neurotoxin-quinolinic-acid-in-human-serum
#2
Ranjana Singh, Sunayana Kashayap, Vimal Singh, Arvind M Kayastha, Hirdyesh Mishra, Preeti Suman Saxena, Anchal Srivastava, Ranjan K Singh
Highly fluorescent nitrogen doped carbon quantum dots (NCQDs) were synthesized using microwave assisted green method. It was characterized by Transmission Electron Microscopy (TEM), FTIR, UV-Visible absorption and Photoluminiscence (PL) techniques. The NCQDs were immobilized with an enzyme named quinolinate phoshphoribosyl transferase (QPRTase). The NCQDs immobilized by QPRTase was used as a fluorescent bioprobe for the selective detection of endogenous neurotoxin quinolinic acid (QA) whose elevated level in serum is marker of many neurological disorders such as Alzheimer's, Huntington's and HIV associated dementia (HAD) as well as deficiency of vitamin B6...
October 10, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29053627/silicon-nanocrystals-with-ph-sensitive-tunable-light-emission-from-violet-to-blue-green
#3
Jing Wang, Junhong Guo, Jing Chen
We fabricated a silicon nanocrystal (NC) suspension with visible, continuous, tunable light emission with pH sensitivity from violet to blue-green. Transmission electron microscopy (TEM) images and X-ray diffraction (XRD) pattern analysis exhibit the highly crystalline nanoparticles of silicon. Photoluminescence (PL) spectra and photoluminescence excitation (PLE) spectra at different pH values, such as 1, 3, 5, 7, 9, and 11, reveal the origins of light emission from the silicon NC suspension, which includes both the quantum confinement effect and surface bonding...
October 20, 2017: Sensors
https://www.readbyqxmd.com/read/29053281/insights-into-water-induced-phase-separation-in-itraconazole-hydroxypropylmethyl-cellulose-spin-coated-and-spray-dried-dispersions
#4
Naila A Mugheirbi, Patrick J Marsac, Lynne S Taylor
For amorphous solid dispersions, understanding the phase behavior of a given drug-polymer blend and factors that influence miscibility is crucial to design an optimally performing formulation. However, it can be challenging to fully map the phase behavior of some systems, especially those produced using a co-solvent system. In this study, a comprehensive investigation of phase separation in itraconazole-hydroxypropylmethylcellulose (ITZ-HPMC) blends fabricated using solvent evaporation processes, including spin coating and spray drying, has been carried out...
October 20, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/29052468/evaluation-of-the-content-of-tio2-nanoparticles-in-the-coatings-of-chewing-gums
#5
William Dudefoi, Hélène Terrisse, Aurelian Florin Popa, Eric Gautron, Bernard Humbert, Marie-Hélène Ropers
Titanium dioxide is a metal oxide used as a white pigment in many food categories, including confectionery. Due to differences in the mass fraction of nanoparticles contained in TiO2, the estimated intakes of TiO2 nanoparticles differ by a factor of 10 in the literature. To resolve this problem, a better estimation of the mass of nanoparticles present in food products is needed. In this study, we focused our efforts on chewing gum, which is one of the food products contributing most to the intake of TiO2. The coatings of four kinds of chewing gum, where the presence of TiO2 was confirmed by Raman spectroscopy, were extracted in aqueous phases...
October 20, 2017: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
https://www.readbyqxmd.com/read/29052215/transmission-electron-microscopy-imaging-to-analyze-chromatin-density-distribution-at-the-nanoscale-level
#6
Tohnyui Ndinyanka Fabrice, Lusik Cherkezyan, Christoph Ringli, Célia Baroux
Transmission electron microscopy (TEM) is used to study the fine ultrastructural organization of cells. Delicate specimen preparation is required for results to reflect the "native" ultrastructural organization of subcellular features such as the nucleus. Despite the advent of high-resolution, fluorescent imaging of chromatin components, TEM still provides a unique and complementary level of resolution capturing chromatin organization at the nanoscale level. Here, we describe the workflow, from tissue preparation, TEM image acquisition and image processing, for obtaining a quantitative description of chromatin density distribution in plant cells, informing on local fluctuations and periodicity...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29052070/the-feasibility-of-laparoscopic-rectal-resection-in-patients-undergoing-reoperation-after-transanal-endoscopic-microsurgery-tem
#7
M Ortenzi, R Ghiselli, A Paolucci, M Guerrieri
BACKGROUND: The success of transanal endoscopic microsurgery (TEM) for early rectal cancer depends on proper indications and strict patient selection. When unfavorable pathologic features are identified after TEM operation, total mesorectal excision is recommended to minimize the risk of recurrence. In this study, data were collected in a retrospective series of patients to determine the results of laparoscopic reoperation after TEM. METHODS: All patients underwent an accurate rectal-digital examination and clinical tumor staging by transanal endosonography, CT, and/or MRI...
October 19, 2017: Surgical Endoscopy
https://www.readbyqxmd.com/read/29051519/from-porous-to-dense-nanostructured-%C3%AE-ti-alloys-through-high-pressure-torsion
#8
Conrado R M Afonso, Angelica Amigó, Vladimir Stolyarov, Dmitri Gunderov, Vicente Amigó
β-Ti alloys have low elastic modulus, good specific strength and high corrosion resistance for biomaterial applications. Noble elements, such as Nb, Ta and Mo, are used to obtain β-Ti due to their chemical biocompatibility. However, due to their refractory nature, β-Ti requires specific processing routes. Powder metallurgy (P/M) allows for the development of new β-Ti alloys with decreasing costs, but dealing with high-elemental-content alloys can lead to a lack of diffusion and grain growth. One method to refine the structure and improve mechanical properties is a severe plastic deformation technique through high-pressure torsion (HPT)...
October 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29050608/magnetic-nanohydrogel-obtained-by-miniemulsion-polymerization-of-poly-acrylic-acid-grafted-onto-derivatized-dextran
#9
Rodolfo Debone Piazza, Eloiza da Silva Nunes, Wesley Renato Viali, Sebastião William da Silva, Fermin Herrera Aragón, José Antônio Huamaní Coaquira, Paulo César de Morais, Rodrigo Fernando Costa Marques, Miguel Jafelicci
This study describes the synthesis of magnetic nanohydrogels by miniemulsion polymerization technique. Dextran was derivatized by the glycidyl methacrylate to anchor vinyl groups on polysaccharides backbone, allowing its use as a macromonomer for miniemulsion polymerization, as confirmed by proton nuclear magnetic resonance spectroscopy ((13)C NMR). Magnetite nanoparticles were synthesized by coprecipitation, followed by air oxidation to maghemite. The results of X-ray diffractometry (XRD), Raman and transmission electron microscopy (TEM) analysis showed that maghemite nanoparticles were obtained with a diameter of 5...
December 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/29050605/isolation-of-cellulose-ii-nanospheres-from-flax-stems-and-their-physical-and-morphological-properties
#10
Jérémy Astruc, Malladi Nagalakshmaiah, Gaétan Laroche, Michel Grandbois, Saïd Elkoun, Mathieu Robert
In this study, cellulose-II nanospheres (CNS) were extracted from flax fibers and analyzed to understand the crystalline, functional and morphological properties by means of X-ray Diffraction (X-RD), Fourier Transform Infrared (FT-IR) and Scanning Electron Microscopy (SEM). FT-IR and SEM results indicate the effective removal of extractives, lignin and hemicellulose. X-RD results clearly show the transformation from cellulose-I to cellulose-II during the mercerization process. Further, the resulting cellulose fibers were treated with sulfuric acid in order to obtain cellulose nanospheres (CNS)...
December 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/29050583/characterization-antioxidant-property-and-cytoprotection-of-exopolysaccharide-capped-elemental-selenium-particles-synthesized-by-bacillus-paralicheniformis-sr14
#11
Yuanzhi Cheng, Xiao Xiao, Xiaoxiao Li, Deguang Song, Zeqing Lu, Fengqin Wang, Yizhen Wang
Instead of using existing methods to chemically synthesize elemental selenium particles (CheSePs), which first require separating and purifying polysaccharides or proteins and adding extra reducing agent, this study applied a novel method to directly assemble exopolysaccharide-capped biogenic elemental selenium particles (EPS-BioSePs) by Bacillus paralicheniformis SR14 during the metabolic process. Characterization by energy dispersive X-ray spectrometry (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), size measurement and chemical composition analysis verified that EPS-BioSePs exhibited a monodispersed and homogeneous spherical structure 293...
December 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/29049927/electron-tomography-of-whole-cultured-cells-using-novel-transmission-electron-imaging-technique
#12
Taiga Okumura, Minami Shoji, Akiko Hisada, Yusuke Ominami, Sukehiro Ito, Tatsuo Ushiki, Masato Nakajima, Takashi Ohshima
Since a three-dimensional (3D) cellular ultrastructure is significant for biological functions, it has been investigated using various electron microscopic techniques. Although transmission electron microscopy (TEM)-based techniques are traditionally used, cells must be embedded in resin and sliced into ultrathin sections in sample preparation processes. Block-face observation using a scanning electron microscope (SEM) has also been recently applied to 3D observation of cellular components, but this is a destructive inspection and does not allow re-examination...
October 16, 2017: Micron: the International Research and Review Journal for Microscopy
https://www.readbyqxmd.com/read/29049347/correlative-microscopy-of-the-constituents-of-a-dinosaur-rib-fossil-and-hosting-mudstone-implications-on-diagenesis-and-fossil-preservation
#13
Jung-Kyun Kim, Yong-Eun Kwon, Sang-Gil Lee, Chang-Yeon Kim, Jin-Gyu Kim, Min Huh, Eunji Lee, Youn-Joong Kim
We have applied correlative microscopy to identify the key constituents of a dorsal rib fossil from Koreanosaurus boseongensis and its hosting mudstone discovered at the rich fossil site in Boseong, South Korea, to investigate the factors that likely contributed to diagenesis and the preservation of fossil bone. Calcite and illite were the commonly occurring phases in the rib bone, hosting mudstone, and the boundary region in-between. The boundary region may have contributed to bone preservation once it fully formed by acting as a protective shell...
2017: PloS One
https://www.readbyqxmd.com/read/29048916/reduced-magnetism-in-core-shell-magnetite-mof-composites
#14
Sameh K Elsaidi, Michael Sinnwell, Debasis Banerjee, Arun Devaraj, Ravi K Kukkadapu, Timothy Droubay, Zimin Nie, Libor Kovarik, Murugesan Vijayakumar, Sandeep Manandhar, Manjula I Nandasiri, B Peter McGrail, Praveen K Thallapally
The magnetic susceptibility of core-shell microspheres was found to decline after the growth of a metal-organic framework (MOF) shell on a synthesized magnetite (Fe3O4) core. Detailed structural analysis of the core-shell particles using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atom probe tomography (ATP), and 57Fe-Mössbauer spectroscopy suggest the distribution of MOF precursors inside the magnetic core resulted in the oxidation of the iron oxide core.
October 19, 2017: Nano Letters
https://www.readbyqxmd.com/read/29048910/solvent-dielectricity-modulated-helical-assembly-and-morphologic-transformation-of-achiral-surfactant-inorganic-cluster-ionic-complexes
#15
Jing Zhang, Xiaofei Chen, Wen Li, Bao Li, Lixin Wu
Ionic complexes comprising of single/double chain cationic surfactant and Lindqvist-type polyoxomolybdate anionic cluster were used for controlled self-assembly in organic solutions. In the solvent with low dielectric constant the complexes self-assembled into flat ribbon like lamellar aggregations with an inverse bilayer substructure where the cluster located at the middle. Under the condition of increased dielectric constant, the solvent triggered the formation of helical self-assemblies, which finally transformed from helical ribbons to the flower-like assemblies due to the bilayer becoming excessive twisting...
October 19, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29048834/-preparation-and-performance-characterization-of-gold-nanoparticles-modified-chiral-capillary-electrochromatography-stationary-phase
#16
Lele Xiong, Ruijun Li, Yibing Ji
Gold nanoparticles (GNPs, 15 nm) were prepared and introduced to amino groups derived silica monolithic column. Bovine serum albumin (BSA) was immobilized via covalent modification method onto the carboxylic functionalized GNPs to afford chiral stationary phase (CSP) for enantioseparation. GNPs were well dispersed and successfully incorporated onto the columns with the contents as high as 17.18% by characterization method such as transmission electron microscopy (TEM), ultraviolet (UV)-visible absorption spectra and scanning electron microscopy (SEM)...
July 8, 2017: Se Pu, Chinese Journal of Chromatography
https://www.readbyqxmd.com/read/29048411/early-versus-6-12-week-postpartum-glucose-tolerance-testing-for-women-with-gestational-diabetes
#17
E B Carter, S Martin, L A Temming, G A Colditz, G A Macones, M G Tuuli
OBJECTIVE: The objective of this study is to estimate the accuracy of early oral glucose tolerance testing (GTT), to predict impaired glucose tolerance. STUDY DESIGN: This was a prospective cohort study. Women received an early 75 g 2 h GTT between postpartum days 2-4 and again 6-12 weeks postpartum. The ability of the early GTT to accurately detect impaired glucose tolerance and diabetes was assessed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive values (NPVs)...
October 19, 2017: Journal of Perinatology: Official Journal of the California Perinatal Association
https://www.readbyqxmd.com/read/29046858/fabrication-of-poly-styrene-co-maleic-anhydride-ag-spheres-with-high-surface-charge-intensity-and-their-self-assembly-into-photonic-crystal-films
#18
Jiajie Bi, Genrui Fan, Suli Wu, Xin Su, Hongbo Xia, Shu-Fen Zhang
Herein, we developed a method to prepare monodisperse poly(styrene-co-maleic anhydride)@Ag (PSMA@Ag) core-shell microspheres with high surface charge intensity by using an in situ reduction method. In this method, ethylenediamine tetraacetic acid tetrasodium salt (Na4EDTA) was used as a reducing agent to promote the growth of Ag, and at the same time endowed the PSMA@Ag spheres with a surface charge. The monodispersity of PSMA and PSMA@Ag and the ordered array of the photonic crystal films were characterized by using SEM...
October 2017: ChemistryOpen
https://www.readbyqxmd.com/read/29046823/functionalization-of-ti-40nb-implant-material-with-strontium-by-reactive-sputtering
#19
Markus Göttlicher, Marcus Rohnke, Yannik Moryson, Jürgen Thomas, Joachim Sann, Anja Lode, Matthias Schumacher, Romy Schmidt, Stefan Pilz, Annett Gebert, Thomas Gemming, Jürgen Janek
BACKGROUND: Surface functionalization of orthopedic implants with pharmaceutically active agents is a modern approach to enhance osseointegration in systemically altered bone. A local release of strontium, a verified bone building therapeutic agent, at the fracture site would diminish side effects, which could occur otherwise by oral administration. Strontium surface functionalization of specially designed titanium-niobium (Ti-40Nb) implant alloy would provide an advanced implant system that is mechanically adapted to altered bone with the ability to stimulate bone formation...
2017: Biomaterials Research
https://www.readbyqxmd.com/read/29046407/an-improved-esbl-detection-test-utilizing-aztreonam-clavulanate
#20
Gina K Thomson, Maaz Ayaz, Kelli Lutes, Kenneth S Thomson
Clinical laboratories test for ESBLs for epidemiological and infection control purposes and also for potential to cause therapeutic failures with cephalosporins. Testing can be problematic because the CLSI does not recommend testing of all producers of ESBLs and also falsely negative results may occur with isolates that co-produce AmpC. Boronic acid supplemented tests can enhance ESBL detection in AmpC producers. Because aztreonam inhibits AmpCs, a study was designed to compare ESBL detection by the CLSI disk test (CLSI), a boronic acid supplemented CLSI disk test (CLSI + BA), and an aztreonam + clavulanate disk test (ATM + CA)...
October 18, 2017: Journal of Clinical Microbiology
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