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https://www.readbyqxmd.com/read/29377676/insights-into-the-toxicity-of-triclosan-to-green-microalga-chlorococcum-sp-using-synchrotron-based-fourier-transform-infrared-spectromicroscopy-biophysiological-analyses-and-roles-of-environmental-factors
#1
Xiaying Xin, Guohe Huang, Chunjiang An, Charley Huang, Harold Weger, Shan Zhao, Yang Zhou, Scott M Rosendahl
This study investigated the toxicity of triclosan to the green microalga Chlorococcum sp. under multiple environmental stressors. The interactions between triclosan and environmental stressors were explored through full two-way factorial, synchrotron-based Fourier transform infrared spectromicroscopy, and principal component analyses. Phosphorus concentration, pH * phosphorus concentration, temperature * pH * NaCl concentration were the most statistically significant factors under triclosan exposure. The variation of those factors would have a huge impact on biophysiological performances...
January 29, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29359936/multiplex-infrared-spectroscopy-imaging-for-monitoring-spatially-resolved-redox-chemistry
#2
Lucyano J A Macedo, Frank Nelson Crespilho
IR spectroscopy is an excellent method for understanding surface redox chemistry. However, obtaining sufficient spatial resolution to analyze in situ surface redox reactions is challenging because the aqueous sampling environments is unsuitable for IR spectroscopy. This unsuitability arises because of the vibrational contribution of water. In this communication, we demonstrate a solution to this problem, where the key development enabling the coupling of spectromicroscopy with electrochemical measurements is a CaF2/electrolyte/Au sandwich IR-sensitive sample holder that acts as an electrochemical cell...
January 23, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29322945/observation-of-layered-antiferromagnetism-in-self-assembled-parallel-nisi-nanowire-arrays-on-si-110-by-spin-polarized-scanning-tunneling-spectromicroscopy
#3
Ie-Hong Hong, Hsin-Zan Hsu
The layered antiferromagnetism of parallel nanowire arrays self-assembled on Si(110) has been observed at room temperature by direct imaging of both the topographies and magnetic domains using spin-polarized scanning tunneling microscopy/spectroscopy (SP-STM/STS). The topographic STM images reveal that the self-assembled unidirectional and parallel NiSi nanowires grow into the Si(110) substrate along the [-110] direction (i.e., the endotaxial growth) and exhibit multiple-layer growth. The spatially-resolved SP-STS maps show that these parallel NiSi nanowires of different heights produce two opposite magnetic domains, depending on the heights of either even or odd layers in the layer stack of the NiSi nanowires...
January 11, 2018: Nanotechnology
https://www.readbyqxmd.com/read/29159351/a-quantitative-analysis-of-the-supercontraction-induced-molecular-disorientation-of-major-ampullate-spider-silk
#4
J Dionne, T Lefèvre, P Bilodeau, M Lamarre, M Auger
Spider silks exhibit remarkable properties, among which the so-called supercontraction, a physical phenomenon by which fibers undergo a longitudinal shrinkage and a radial swelling when exposed to water. The process is marked by a significant decrease in chain orientation resulting from plasticisation of the amorphous phase. Despite several studies that determined the Hermans orientation function, more quantitative data are required to be able to describe theoretically the macroscopic water-induced shrinkage from molecular reorganization...
November 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29155910/probing-plasma-fluorinated-graphene-via-spectromicroscopy
#5
C Struzzi, M Scardamaglia, N Reckinger, H Sezen, M Amati, L Gregoratti, J-F Colomer, C Ewels, R Snyders, C Bittencourt
Plasma fluorination of graphene is studied using a combination of spectroscopy and microscopy techniques, giving insight into the yield and fluorination mechanism for functionalization of supported graphene with both CF4 and SF6 gas precursors. Ion acceleration during fluorination is used to probe the effect on grafting functionalities. Adatom clustering, which occurs with CF4 plasma treatment, is suppressed when higher kinetic energy is supplied to the ions. During SF6 plasma functionalization, the sulfur atoms tend to bond to bare copper areas instead of affecting the graphene chemistry, except when the kinetic energy of the ions is restricted...
November 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29126948/polymerisation-antibacterial-and-bioactivity-properties-of-experimental-orthodontic-adhesives-containing-triclosan-loaded-halloysite-nanotubes
#6
Felipe Weidenbach Degrazia, Bruna Genari, Vicente Castelo Branco Leitune, Rodrigo Alex Arthur, Santiago Arias Luxan, Susana Maria Werner Samuel, Fabrício Mezzomo Collares, Salvatore Sauro
OBJECTIVE: To evaluate the immediate enamel bond strength, in situ degree of conversion and the polymerisation rate of three experimental orthodontic adhesives containing triclosan-loaded halloysite nanotubes. The antibacterial and bioactivity properties of such experimental materials were also assessed. MATERIALS AND METHODS: Three experimental orthodontic adhesives were formulated by incorporating triclosan-loaded halloysite nanotubes (TCN-HNT) at different concentrations (5wt%, 10wt% and 20wt%) into a resin blend (Control)...
November 7, 2017: Journal of Dentistry
https://www.readbyqxmd.com/read/29035310/a-sub-microanalysis-approach-in-chemical-characterisation-of-gold-nanorods-formed-by-a-novel-polymer-immobilised-gold-seeds-base
#7
Majid Kazemian Abyaneh, Tohru Araki, Burkhard Kaulich
Gold nanorods (GNRs) have been fabricated by a novel polymer-immobilised seed mediated method using ultraviolet (UV) photoreduced gold-polymethylmethacrylate (Au-PMMA) nanocomposites as a seed platform and characterised at sub-micron scale regime with synchrotron-based techniques; near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and X-ray fluorescence (XRF) mapping. In this report, it is shown that investigating polymer nanocomposites using combination of XRF mapping and NEXAFS spectromicroscopy can help to see the growth phenomenon from different perspective than conventional characterisation techniques...
October 16, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28980800/tip-enhanced-raman-spectromicroscopy-on-the-angstrom-scale-bare-and-co-terminated-ag-tips
#8
Nicholas Tallarida, Joonhee Lee, Vartkess Ara Apkarian
The tip is key to the successful execution of tip-enhanced Raman scattering (TERS) measurements in the single molecule limit. We show that nanoscopically smooth silver tips, batch produced through field-directed sputter sharpening, reliably attain TERS with enhancement factors that reach 10(13), as measured by the Raman spectra of single CO molecules attached to the tip apex. We validate the bare tips by demonstrating spectromicroscopy with submolecular spatial resolution and underscore that TERS is a near-field effect that does not obey simple selection rules...
October 9, 2017: ACS Nano
https://www.readbyqxmd.com/read/28976729/tip-enhanced-raman-spectromicroscopy-of-co-ii-tetraphenylporphyrin-on-au-111-toward-the-chemists-microscope
#9
Joonhee Lee, Nicholas Tallarida, Xing Chen, Pengchong Liu, Lasse Jensen, Vartkess Ara Apkarian
Atomically terminated and nanoscopically smooth silver tips effectively focus light on the angstrom scale, allowing tip-enhanced Raman spectromicroscopy (TER-sm) with single molecule sensitivity and submolecular spatial resolution. Through measurements carried out on cobalt-tetraphenylporphyrin (CoTPP) adsorbed on Au(111), we highlight peculiarities of vibrational spectromicroscopy with light confined on the angstrom scale. Field-gradient-driven spectra, orientational fingerprinting, and sculpting of local fields by atomic morphology of the junction are elucidated through measurements that range from 2D arrays at room temperature to single molecule manipulations at 5 K...
October 12, 2017: ACS Nano
https://www.readbyqxmd.com/read/28939848/physical-origins-of-current-and-temperature-controlled-negative-differential-resistances-in-nbo2
#10
Suhas Kumar, Ziwen Wang, Noraica Davila, Niru Kumari, Kate J Norris, Xiaopeng Huang, John Paul Strachan, David Vine, A L David Kilcoyne, Yoshio Nishi, R Stanley Williams
Negative differential resistance behavior in oxide memristors, especially those using NbO2, is gaining renewed interest because of its potential utility in neuromorphic computing. However, there has been a decade-long controversy over whether the negative differential resistance is caused by a relatively low-temperature non-linear transport mechanism or a high-temperature Mott transition. Resolving this issue will enable consistent and robust predictive modeling of this phenomenon for different applications...
September 22, 2017: Nature Communications
https://www.readbyqxmd.com/read/28774096/in-situ-soft-x-ray-spectromicroscopy-of-early-tricalcium-silicate-hydration
#11
Sungchul Bae, Manabu Kanematsu, Daniel Hernández-Cruz, Juhyuk Moon, David Kilcoyne, Paulo J M Monteiro
The understanding and control of early hydration of tricalcium silicate (C₃S) is of great importance to cement science and concrete technology. However, traditional characterization methods are incapable of providing morphological and spectroscopic information about in situ hydration at the nanoscale. Using soft X-ray spectromicroscopy, we report the changes in morphology and molecular structure of C₃S at an early stage of hydration. In situ C₃S hydration in a wet cell, beginning with induction (~1 h) and acceleration (~4 h) periods of up to ~8 h, was studied and compared with ex situ measurements in the deceleration period after 15 h of curing...
December 1, 2016: Materials
https://www.readbyqxmd.com/read/28772490/effects-of-incorporating-high-volume-fly-ash-into-tricalcium-silicate-on-the-degree-of-silicate-polymerization-and-aluminum-substitution-for-silicon-in-calcium-silicate-hydrate
#12
Sungchul Bae, Rae Taylor, David Kilcoyne, Juhyuk Moon, Paulo J M Monteiro
This study assesses the quantitative effects of incorporating high-volume fly ash (HVFA) into tricalcium silicate (C₃S) paste on the hydration, degree of silicate polymerization, and Al substitution for Si in calcium silicate hydrate (C-S-H). Thermogravimetric analysis and isothermal conduction calorimetry showed that, although the induction period of C₃S hydration was significantly extended, the degree of hydration of C₃S after the deceleration period increased due to HVFA incorporation. Synchrotron-sourced soft X-ray spectromicroscopy further showed that most of the C₃S in the C₃S-HVFA paste was fully hydrated after 28 days of hydration, while that in the pure C₃S paste was not...
February 4, 2017: Materials
https://www.readbyqxmd.com/read/28760619/gamma-irradiated-human-amniotic-membrane-decellularised-with-sodium-dodecyl-sulfate-is-a-more-efficient-substrate-for-the-ex-vivo-expansion-of-limbal-stem-cells
#13
G S Figueiredo, S Bojic, P Rooney, S-P Wilshaw, C J Connon, R M Gouveia, C Paterson, G Lepert, H S Mudhar, F C Figueiredo, M Lako
The gold standard substrate for the ex vivo expansion of human limbal stem cells (LSCs) remains the human amniotic membrane (HAM) but this is not a defined substrate and is subject to biological variability and the potential to transmit disease. To better define HAM and mitigate the risk of disease transmission, we sought to determine if decellularisation and/or γ-irradiation have an adverse effect on culture growth and LSC phenotype. Ex vivo limbal explant cultures were set up on fresh HAM, HAM decellularised with 0...
October 1, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28719608/cholesterol-esterification-inhibition-and-imatinib-treatment-synergistically-inhibit-growth-of-bcr-abl-mutation-independent-resistant-chronic-myelogenous-leukemia
#14
Shovik Bandyopadhyay, Junjie Li, Elie Traer, Jeffrey W Tyner, Amy Zhou, Stephen T Oh, Ji-Xin Cheng
Since the advent of tyrosine kinase inhibitors (TKIs) such as imatinib, nilotinib, and dasatinib, chronic myelogenous leukemia (CML) prognosis has improved greatly. However, ~30-40% of patients develop resistance to imatinib therapy. Although most resistance is caused by mutations in the BCR-ABL kinase domain, 50-85% of these patients develop resistance in the absence of new mutations. In these cases, targeting other pathways may be needed to regain clinical response. Using label-free Raman spectromicroscopy, we evaluated a number of leukemia cell lines and discovered an aberrant accumulation of cholesteryl ester (CE) in CML, which was found to be a result of BCR-ABL kinase activity...
2017: PloS One
https://www.readbyqxmd.com/read/28702656/polarization-landscape-effects-in-soft-x-ray-induced-surface-chemical-decomposition-of-lead-zirco-titanate-evidenced-by-photoelectron-spectromicroscopy
#15
Laura E Abramiuc, Liviu C Tănase, Alexei Barinov, Nicoleta G Apostol, Cristina Chirilă, Lucian Trupină, Lucian Pintilie, Cristian M Teodorescu
The stability of thin films of lead zirco-titanate (PZT) under intense soft X-ray beams is investigated by time-resolved photoelectron spectromicroscopy with a lateral resolution below 1 micrometer. Surface dissociation is observed when samples are irradiated with intense (5 × 10(23) photons per s per m(2)) soft X-rays, with promotion of reduced lead on the surface. On areas exhibiting outwards polarization (P((+))), the reduced lead is formed at the expense of P((+))-PZT. On areas presenting co-existing P((+)) states with areas without out-of-plane polarization (P((0))), the reduced lead is formed at the expense of the P((0))-PZT component, while the P((+))-PZT remains constant...
July 12, 2017: Nanoscale
https://www.readbyqxmd.com/read/28692273/protein-mixture-segregation-at-coffee-ring-real-time-imaging-of-protein-ring-precipitation-by-ftir-spectromicroscopy
#16
Sun Choi, Giovanni Birarda
During natural drying process, all solutions and suspensions tend to form the so-called "coffee-ring" deposits. This phenomenon, by far, has been interpreted by the hydrodynamics of evaporating fluids. However, in this study, by applying Fourier transform infrared imaging (FTIRI), it is possible to observe the segregation and separation of a protein mixture at the "ring", hence we suggest a new way to interpret "coffee-ring effect" of solutions. The results explore the dynamic process that leads to the ring formation in case of model plasma proteins, such as BGG (bovine γ globulin), BSA (bovine serum albumin), and Hfib (human fibrinogen), and also report fascinating discovery of the segregation at the ring deposits of two model proteins BGG and BSA, which can be explained by an energy kinetic model, only...
July 18, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28636921/characterizing-intracellular-ice-formation-of%C3%A2-lymphoblasts-using-low-temperature-raman%C3%A2-spectroscopy
#17
Guanglin Yu, Yan Rou Yap, Kathryn Pollock, Allison Hubel
Raman microspectroscopy was used to quantify freezing response of cells to various cooling rates and solution compositions. The distribution pattern of cytochrome c in individual cells was used as a measure of cell viability in the frozen state and this metric agreed well with the population-averaged viability and trypan blue staining experiments. Raman imaging of cells demonstrated that intracellular ice formation (IIF) was common and did not necessarily result in cell death. The amount of intracellular ice as well as ice crystal size played a role in determining whether or not ice inside the cell was a lethal event...
June 20, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28471186/chemical-and-morphological-inhomogeneity-of-aluminum-metal-and-oxides-from-soft-x-ray-spectromicroscopy
#18
Alison B Altman, C Das Pemmaraju, Selim Alayoglu, John Arnold, Corwin H Booth, Augustin Braun, Christopher E Bunker, Alexandre Herve, Stefan G Minasian, David Prendergast, David K Shuh, Tolek Tyliszczak
Oxygen and aluminum K-edge X-ray absorption spectroscopy (XAS), imaging from a scanning transmission X-ray microscope (STXM), and first-principles calculations were used to probe the composition and morphology of bulk aluminum metal, α- and γ-Al2O3, and several types of aluminum nanoparticles. The imaging results agreed with earlier transmission electron microscopy studies that showed a 2 to 5 nm thick layer of Al2O3 on all the Al surfaces. Spectral interpretations were guided by examination of the calculated transition energies, which agreed well with the spectroscopic measurements...
May 4, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28406227/50-nm-resolution-full-field-x-ray-microscope-without-chromatic-aberration-using-total-reflection-imaging-mirrors
#19
Satoshi Matsuyama, Shuhei Yasuda, Jumpei Yamada, Hiromi Okada, Yoshiki Kohmura, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
X-ray spectromicroscopy with a full-field imaging technique is a powerful method for chemical analysis of heterogeneous complex materials with a nano-scale spatial resolution. For imaging optics, an X-ray reflective optical system has excellent capabilities with highly efficient, achromatic, and long-working-distance properties. An advanced Kirkpatrick-Baez geometry that combines four independent mirrors with elliptic and hyperbolic shapes in both horizontal and vertical directions was developed for this purpose, although the complexity of the system has a limited applicable range...
April 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28399502/molecular-toxicity-of-triclosan-and-carbamazepine-to-green-algae-chlorococcum-sp-a-single-cell-view-using-synchrotron-based-fourier-transform-infrared-spectromicroscopy
#20
Xiaying Xin, Guohe Huang, Xia Liu, Chunjiang An, Yao Yao, Harold Weger, Peng Zhang, Xiujuan Chen
Although pharmaceuticals and personal care products have been used and introduced into the environment in large quantities, little information on potential ecological risks is currently available considering their effects on living organisms. We verified the feasibility of using synchrotron-based Fourier Transform Infrared (SR-FTIR) spectromicroscopy to explore in vivo toxic effects on single living Chlorococcum sp. cells. The study provided important information to achieve a better understanding of the toxic mechanism of triclosan and carbamazepine on living algae Chlorococcum sp...
July 2017: Environmental Pollution
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