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Secondary ion mass spectrometry

Wen-Bao Sun, Xiao-Fei Yang, Zi-Bo Zhang, Wing-Han Wong, Dao-Yin Yu, Edwin Yue-Bun Pun, De-Long Zhang
Ti<sup>4+</sup>-diffused Zr<sup>4+</sup>/Er<sup>3+</sup>-codoped LiNbO<sub>3</sub> strip waveguide was fabricated on an X-cut LiNbO<sub>3</sub> substrate by thermal diffusion in sequence of Er<sup>3+</sup>, Zr<sup>4+</sup> and Ti<sup>4+</sup>. Secondary ion mass spectrometry study shows that the Ti<sup>4+</sup> ions follow a sum of two error functions in the width direction and a Gauss function in the depth direction of the waveguide...
April 17, 2017: Optics Express
Alena Wagner, Kristina Glenske, Anja Henß, Benjamin Kruppke, Sina Rößler, Thomas Hanke, Andreas Moritz, Marcus Rohnke, Monika Kressin, Stefan Arnhold, Reinhard Schnettler, Sabine Wenisch
Presently, we aim to elucidate osteogenic effects of two silica-based xerogels with different degrees of bioactivity on human bone-derived mesenchymal stromal cells. By means of scanning electron microscopy and quantitative PCR enhanced osteogenic effects and the formation of an extracellular matrix could be ascribed to the sample with lower bioactivity. Given the high levels of bioactivity, the cells revealed remarkable sensitivity to extremely low calcium levels of the media. Therefore, additional experiments were performed to elucidate cell behavior under calcium deficient conditions...
April 20, 2017: Biomedical Materials
R S Renslow, M J Marshall, A E Tucker, W B Chrisler, X-Y Yu
Biofilms are comprised of microbial cells and an extracellular polymeric substance (EPS) matrix that supports interactions between community members and with the local environment. The highly hydrated EPS matrix makes the application of many biofilm visualization techniques difficult. Hence, to better visualize how biofilms interact with their environment, there is a need for imaging techniques to monitor hydrated state biofilm dynamics. We employed an in situ dynamic approach to construct label-free images of biofilms...
April 20, 2017: Analyst
Wenjun Wu, Huaide Xiang, Wei Fan, Jinglin Wang, Haifeng Wang, Xin Hua, Zhaohui Wang, Yi-Tao Long, He Tian, Wei-Hong Zhu
Up to date, development of organic sensitizers has been predominately focused on light harvesting, HOMO and LUMO energy levels, and electron transferring process. In contrast, their adsorption mode as well as dynamic loading behaviour onto nanoporous TiO2 is rarely considered. Herein we have employed the time of flight secondary ion mass spectrometry (TOF-SIMS) to take insight into the competitive dye adsorption mode and kinetics in cosensitized porphyrin system. Using the novel porphyrin dye FW-1 and D-A-π-A featured dye WS-5, the different bond-breaking mode in TOF-SIMS and dynamic dye-loading amount during the coadsorption process are well compared with two different anchoring groups such as benzoic acid and cyanoacrylic acid...
April 20, 2017: ACS Applied Materials & Interfaces
D Dwivedi, K Lepkova, T Becker
Carbon steel is a preferred construction material in many industrial and domestic applications, including oil and gas pipelines, where corrosion mitigation using film-forming corrosion inhibitor formulations is a widely accepted method. This review identifies surface analytical techniques that are considered suitable for analysis of thin films at metallic substrates, but are yet to be applied to analysis of carbon steel surfaces in corrosive media or treated with corrosion inhibitors. The reviewed methods include time of flight-secondary ion mass spectrometry, X-ray absorption spectroscopy methods, particle-induced X-ray emission, Rutherford backscatter spectroscopy, Auger electron spectroscopy, electron probe microanalysis, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission electron microscopy, low-energy electron diffraction, small-angle neutron scattering and neutron reflectometry, and conversion electron Moessbauer spectrometry...
March 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
Chiung-Hui Liu, Hung-Ming Chang, Tsung-Huan Wu, Li-You Chen, Yin-Shuo Yang, To-Jung Tseng, Wen-Chieh Liao
The voltage-gated potassium channels Kv1.1 and Kv1.2 that cluster at juxtaparanodal (JXP) regions are essential in the regulation of nerve excitability and play a critical role in axonal conduction. When demyelination occurs, Kv1.1/Kv1.2 activity increases, suppressing the membrane potential nearly to the equilibrium potential of K(+), which results in an axonal conduction blockade. The recovery of K(+)-dependent communication signals and proper clustering of Kv1.1/Kv1.2 channels at JXP regions may directly reflect nerve regeneration following peripheral nerve injury...
April 12, 2017: Histochemistry and Cell Biology
Mohamad Maaz, Tamara Elzein, Alice Bejjani, Nadine Barroca-Aubry, Bénédicte Lepoittevin, Diana Dragoe, Sandra Mazerat, Bilal Nsouli, Philippe Roger
Poly(ethylene terephthalate) (PET) substrates were modified by means of surface-initiated supplemental activator and reducing agent atom transfer radical polymerization (SI-SARA-ATRP) of 4-vinylpyridine (4VP). Substrates were pretreated in order to graft chloromethylbenzene (CMB) units capable of initiating the radical polymerization reaction of 4VP units. Surface characterization techniques, including Water Contact Angle (WCA), Attenuated Total Reflection (ATR), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) showed a successful grafting of a stable, smooth and homogenous layer of p4VP...
April 2, 2017: Journal of Colloid and Interface Science
Meri J Eichner, Isabell Klawonn, Samuel T Wilson, Sten Littmann, Martin J Whitehouse, Matthew J Church, Marcel Mm Kuypers, David M Karl, Helle Ploug
Gradients of oxygen (O2) and pH, as well as small-scale fluxes of carbon (C), nitrogen (N) and O2 were investigated under different partial pressures of carbon dioxide (pCO2) in field-collected colonies of the marine dinitrogen (N2)-fixing cyanobacterium Trichodesmium. Microsensor measurements indicated that cells within colonies experienced large fluctuations in O2, pH and CO2 concentrations over a day-night cycle. O2 concentrations varied with light intensity and time of day, yet colonies exposed to light were supersaturated with O2 (up to ~200%) throughout the light period and anoxia was not detected...
April 11, 2017: ISME Journal
Oliver Plümper, Helen E King, Thorsten Geisler, Yang Liu, Sonja Pabst, Ivan P Savov, Detlef Rost, Thomas Zack
Serpentinization-fueled systems in the cool, hydrated forearc mantle of subduction zones may provide an environment that supports deep chemolithoautotrophic life. Here, we examine serpentinite clasts expelled from mud volcanoes above the Izu-Bonin-Mariana subduction zone forearc (Pacific Ocean) that contain complex organic matter and nanosized Ni-Fe alloys. Using time-of-flight secondary ion mass spectrometry and Raman spectroscopy, we determined that the organic matter consists of a mixture of aliphatic and aromatic compounds and functional groups such as amides...
April 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
A Portz, M Baur, C R Gebhardt, A J Frank, P Neuderth, M Eickhoff, M Dürr
The influence of the chemical nature of the cluster constituents on the desorption/ionization process was investigated for desorption/ionization induced by neutral SO2 clusters (DINeC). The polar clusters act as a transient matrix in which the desorbed analyte molecules are dissolved during the desorption process. For drop-cast samples, the desorption/ionization efficiency was found to be largely independent of the pH value of the initial solution the samples were prepared from; positive ions were almost always dominant and no multiply charged negative ions were observed...
April 7, 2017: Journal of Chemical Physics
Nhu T N Phan, Marwa Munem, Andrew G Ewing, John S Fletcher
Lipids are abundant biomolecules performing central roles to maintain proper functioning of cells and biological bodies. Due to their highly complex composition, it is critical to obtain information of lipid structures in order to identify particular lipids which are relevant for a biological process or metabolic pathway under study. Among currently available molecular identification techniques, MS/MS in secondary ion mass spectrometry (SIMS) imaging has been of high interest in the bioanalytical community as it allows visualization of intact molecules in biological samples as well as elucidation of their chemical structures...
April 7, 2017: Analytical and Bioanalytical Chemistry
Jean-Baptiste Raina, Peta L Clode, Soshan Cheong, Jeremy Bougoure, Matt R Kilburn, Anthony Reeder, Sylvain Forêt, Michael Stat, Victor Beltran, Peter Thomas-Hall, Dianne Tapiolas, Cherie M Motti, Bill Gong, Mathieu Pernice, Christopher E Marjo, Justin R Seymour, Bette L Willis, David G Bourne
Phytoplankton-bacteria interactions drive the surface ocean sulfur cycle and local climatic processes through the production and exchange of a key compound: dimethylsulfoniopropionate (DMSP). Despite their large-scale implications, these interactions remain unquantified at the cellular-scale. Here we use secondary-ion mass spectrometry to provide the first visualization of DMSP at sub-cellular levels, tracking the fate of a stable sulfur isotope ((34)S) from its incorporation by microalgae as inorganic sulfate to its biosynthesis and exudation as DMSP, and finally its uptake and degradation by bacteria...
April 4, 2017: ELife
Francisco J Lara, Danny Chan, Michael Dickinson, Antony S Lloyd, Stuart J Adams
Direct analysis in real time (DART) was evaluated for the determination of a number of highly polar pesticides using the Quick Polar Pesticides Extraction (QuPPe) method. DART was hyphenated to high resolution mass spectrometry (HRMS) in order to get the required selectivity that allows the determination of these compounds in complex samples such as lettuce and celery. Experimental parameters such as desorption temperature, scanning speed, and distances between the DART ion source and MS inlet were optimized...
March 15, 2017: Journal of Chromatography. A
Amy M Holmes, David J Scurr, Jon R Heylings, Ka-Wai Wan, Gary P Moss
Skin penetration and localisation of chlorhexidine digluconate (CHG) within the skin have been investigated in order to better understand and optimise the delivery using a nano polymeric delivery system of this topically-applied antimicrobial drug. Franz-type diffusion cell studies using in vitro porcine skin and tape stripping procedures were coupled with Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to visualise the skin during various treatments with CHG and polyamidoamine dendrimers (PAMAM)...
March 29, 2017: European Journal of Pharmaceutical Sciences
Alexis J Eugene, Marcelo I Guzman
The variable composition of secondary organic aerosols (SOA) contributes to the large uncertainty for predicting radiative forcing. A better understanding of the reaction mechanisms leading to aerosol formation such as for the photochemical reaction of aqueous pyruvic acid (PA) at λ ≥ 305 nm can contribute to constrain these uncertainties. Herein, the photochemistry of aqueous PA (5-300 mM) continuously sparged with air is re-examined in the laboratory under comparable irradiance at 38° N at noon on a summer day...
April 20, 2017: Journal of Physical Chemistry. A
Nicholas G Welch, Robert M T Madiona, Thomas B Payten, Christopher D Easton, Luisa Pontes-Braz, Narelle Brack, Judith A Scoble, Benjamin W Muir, Paul J Pigram
Antibody orientation at solid phase interfaces plays a critical role in the sensitive detection of biomolecules during immunoassays. Correctly oriented antibodies with solution-facing antigen binding regions have improved antigen capture as compared to their randomly oriented counterparts. Direct characterization of oriented proteins with surface analysis methods still remains a challenge however surface sensitive techniques such as Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) provide information-rich data that can be used to probe antibody orientation...
March 27, 2017: Acta Biomaterialia
Anna C Crecelius, Beate Michalzik, Karin Potthast, Stefanie Meyer, Ulrich S Schubert
Mass spectrometric imaging (MSI) has received considerable attention in recent years, since it allows the molecular mapping of various compound classes, such as proteins, peptides, glycans, secondary metabolites, lipids, and drugs in animal, human, or plant tissue sections. In the present study, the application of laser-based MSI analysis of secondary plant metabolites to monitor their transport from the grass leaves of Dactylis glomerata, over the crop of the grasshopper Chorthippus dorsatus to its excrements, and finally in the soil solution is described...
March 29, 2017: Analytical and Bioanalytical Chemistry
Moritz Buhl, Mark Staniford, Sebastian Lamping, Martin Körsgen, Heinrich F Arlinghaus, Ulrich Kynast, Bart Jan Ravoo
Nanoclays are nanomaterials with versatile adsorptive properties. This contribution describes the generation of micropatterns of a nanoclay ("laponite") on ammonium-terminated, self-assembled monolayers (SAMs) on glass and silicon. Microstructured immobilization of the laponite was performed using micromolding in capillaries (MIMIC). The immobilization was verified using contact angle goniometry, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and fluorescence microscopy...
April 6, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Liang Ye, Arántzazu González-Campo, Tibor Kudernac, Rosario Núñez, Michel de Jong, Wilfred G van der Wiel, Jurriaan Huskens
Monolayer contact doping (MLCD) is a modification of the monolayer doping (MLD) technique that involves monolayer formation of a dopant-containing adsorbate on a source substrate. This source substrate is subsequently brought into contact with the target substrate, upon which the dopant is driven into the target substrate by thermal annealing. Here, we report a modified MLCD process, in which we replace the commonly used Si source substrate by a thermally oxidized substrate with a 100 nm thick silicon oxide layer, functionalized with a monolayer of a dopant-containing silane...
April 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Konstantin V Egorov, Dmitry S Kuzmichev, Pavel S Chizhov, Yuri Yu Lebedinskii, Cheol Seong Hwang, Andrey M Markeev
The plasma-enhanced atomic layer deposition (PEALD) process using Ta(OC2H5)5 as a Ta precursor and plasma-activated hydrogen as a reactant for the deposition of TaOx films with a controllable concentration of oxygen vacancies (VO) is reported herein. The VO concentration control was achieved by varying the hydrogen volume fraction of the hydrogen-argon mixture in the plasma, allowing the control of the leakage current density in the tantalum oxide films within the range of 5 orders of magnitude compared with the Ta2O5 film grown via thermal ALD using the identical Ta precursor and H2O...
April 6, 2017: ACS Applied Materials & Interfaces
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