Determination of elemental distribution in green micro-algae using synchrotron radiation nano X-ray fluorescence (SR-nXRF) and electron microscopy techniques – subcellular localization and quantitative imaging of silver and cobalt uptake by Coccomyxa actinabiotis

Metallomics ◽  
2014 ◽  
Vol 6 (2) ◽  
pp. 316 ◽  
Author(s):  
T. Leonardo ◽  
E. Farhi ◽  
A.-M. Boisson ◽  
J. Vial ◽  
P. Cloetens ◽  
...  
Author(s):  
Ryosuke Kondo ◽  
Takuma Yamato ◽  
Alvaro Muñoz-Noval ◽  
Sadao Honda ◽  
Yoshinori Nishiwaki ◽  
...  

Three dimensional imaging of trace elements in a single hair strand was achieved by a micro X-ray fluorescence computed tomography (µXRF-CT) using synchrotron radiation. A simple rotational mechanism was attached...


1982 ◽  
Vol 15 (2) ◽  
pp. 216-226
Author(s):  
I. T. Steinberger ◽  
U. Asaf ◽  
W. Graeff ◽  
Z. H. Kalman

An experimental method is described for the determination of crystallite dimensions in polycrystalline materials. It is based on studying the geometry of streaks that appear in powder photographs taken with white X-ray radiation. A detailed analysis is presented that includes a differentiation between these streaks and somewhat similar streaks due to asterism. Results by synchrotron radiation from powder samples of various materials are discussed and compared with the crystallite dimensions obtained by other methods. It is demonstrated that the method is largely complementary to measurements by electron microscopy and that it is particularly useful for the determination of the thickness distribution of thin (0.005–0.5 μm) platelets, oriented parallel to the substrate.


Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 921
Author(s):  
Simonetta Muccifora ◽  
Hiram Castillo-Michel ◽  
Francesco Barbieri ◽  
Lorenza Bellani ◽  
Monica Ruffini Castiglione ◽  
...  

Biosolids (Bs) for use in agriculture are an important way for introducing and transferring TiO2 nanoparticles (NPs) to plants and food chain. Roots of Pisum sativum L. plants grown in Bs-amended soils spiked with TiO2 800 mg/kg as rutile NPs, anatase NPs, mixture of both NPs and submicron particles (SMPs) were investigated by Transmission Electron Microscopy (TEM), synchrotron radiation based micro X-ray Fluorescence and micro X-ray Absorption Near-Edge Structure (µXRF/µXANES) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). TEM analysis showed damages in cells ultrastructure of all treated samples, although a more evident effect was observed with single anatase or rutile NPs treatments. Micro-XRF and TEM evidenced the presence of nano and SMPs mainly in the cortex cells near the rhizodermis. Micro-XRF/micro-XANES analysis revealed anatase, rutile, and ilmenite as the main TiO2 polymorphs in the original soil and Bs, and the preferential anatase uptake by the roots. For all treatments Ti concentration in the roots increased by 38–56%, however plants translocation factor (TF) increased mostly with NPs treatment (261–315%) and less with SMPs (about 85%), with respect to control. In addition, all samples showed a limited transfer of TiO2 to the shoots (very low TF value). These findings evidenced a potential toxicity of TiO2 NPs present in Bs and accumulating in soil, suggesting the necessity of appropriate regulations for the occurrence of NPs in Bs used in agriculture.


Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 189
Author(s):  
Nuša Hojnik ◽  
Olivija Plohl ◽  
Matjaž Finšgar

In this work, different electrodes were employed for the determination of Cr(VI) by the cathodic square‑wave voltammetry (SWV) technique and the square-wave adsorptive stripping voltammetry (SWAdSV) technique in combination with diethylenetriaminepentaacetic acid. Using SWV, a comparison of the analytical performance of the bare glassy carbon electrode (GCE), ex situ electrodes (antimony-film—SbFE, copper-film—CuFE, and bismuth-film—BiFE), and the GCE modified with a new magnetic nanocomposite (MNC) material was performed. First, the MNC material was synthesized, i.e., MNPs@SiO2@Lys, where MNPs stands for magnetic maghemite nanoparticles, coated with a thin amorphous silica (SiO2) layer, which was additionally functionalized with derived lysine (Lys). The crystal structure of the prepared MNCs was confirmed by X-ray powder diffraction (XRD), while the morphology and nano-size of the MNCs were investigated by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), where TEM was additionally used to observe the MNP core and silica layer thickness. The presence of functional groups of the MNCs was investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and surface analysis was performed by X-ray photoelectron spectroscopy (XPS). The hydrophilicity of the modified electrodes was also tested by static contact angle measurements. Then, MNPs@SiO2@Lys was applied onto the electrodes and used with the SWV and SWAdSV techniques. All electrodes tested with the SWV technique were effective for Cr(VI) trace determination. On the other hand, the SWAdSV technique was required for ultra-trace determination of Cr(VI). Using the SWAdSV technique, it was shown that a combination of ex situ BiFE with the deposited MNPs@SiO2@Lys resulted in excellent analytical performance (LOQ = 0.1 µg/L, a linear concentration range of 0.2–2.0 µg/L, significantly higher sensitivity compared to the SWV technique, an RSD representing reproducibility of 9.0%, and an average recovery of 98.5%). The applicability of the latter system was also demonstrated for the analysis of a real sample.


1990 ◽  
Vol 68 (6) ◽  
pp. 2719-2722 ◽  
Author(s):  
A. Matsumuro ◽  
M. Kobayashi ◽  
T. Kikegawa ◽  
M. Senoo

2003 ◽  
Vol 321 (2-3) ◽  
pp. 221-232 ◽  
Author(s):  
A Yilmazbayhan ◽  
O Delaire ◽  
A.T Motta ◽  
R.C Birtcher ◽  
J.M Maser ◽  
...  

2003 ◽  
Vol 67 (2) ◽  
pp. 219-231 ◽  
Author(s):  
H. W. Langmi ◽  
J. Watt

Computer-controlled scanning electron microscopy (CCSEM) has been assessed for the determination of form and size distribution of heavy metals in urban contaminated soils. Metal distributions within individual particles were determined using X-ray element mapping. The sites selected for study were (1) around a landfill site, previously a colliery in Wolverhampton, UK and (2) a private garden adjacent to a railway in Nottingham, UK. Backscattered thresholding techniques were used to isolate the Pb-containing categories. The classification results for both Wolverhampton and Nottingham soils were generally similar but more Pb-containing classes were observed for the Nottingham samples when a comparison was made between results of the same size fractions. However, difficulties with the technique arose when particles showing chemically similar weathering crusts were assigned to the same class, despite having different internal compositions. The CCSEM data therefore need to be interpreted with caution and their application limited to situations in which particle internal complexity is not an issue.


1993 ◽  
Vol 313 ◽  
Author(s):  
Mary Beth Stearns ◽  
Yuanda Cheng

ABSTRACTSeveral series of CoxAg1-x granular thin films (-3000Å) were fabricated by coevapora-tion of Co and Ag in a dual e-beam UHV deposition system at varying substrate temperatures. These films have low field magnetoresistance values as large as 31% at room temperature and 65% at liquid N2 temperature. The structure of the films was determined using magnetization measurements as well as x-ray and various electron microscopy techniques. The composition was determined using Rutherford backscattering spectroscopy. The Magnetoresistance was measured at both room and liquid N2 temperatures.We deduce from the magnetization and RBS Measurements that the films consist of Co globules embedded in a Ag Matrix and that there is no appreciable mixing of the Co and Ag atoms in the films deposited at substrate temperatures ≥ 400°K. The size of the Co globules is seen to increase with increasing Co concentration and the maximum magnetoresistance occurs in those films having the smallest Ag thickness which provides magnetic isolation of the Co globules.We suggest that the large magnetoresistance of these films arises from the same mechanism which causes the low field magnetoresistance in pure ferromagnets, namely, the scattering of the highly polarized d conduction electrons of the Co at magnetic boundaries. The large increase in the room temperature magnetoresistance of the CO/Ag films as compared to those of pure 3d ferromagnetic films is due to the distance between the magnetic boundaries being reduced to a few nanometers, because of the small size of the single domain Co globules, as compared to a few microns in 3d ferromagnets.


2017 ◽  
Vol 73 (8) ◽  
pp. 702-709 ◽  
Author(s):  
Hisashi Naitow ◽  
Yoshinori Matsuura ◽  
Kensuke Tono ◽  
Yasumasa Joti ◽  
Takashi Kameshima ◽  
...  

Serial femtosecond crystallography (SFX) with an X-ray free-electron laser is used for the structural determination of proteins from a large number of microcrystals at room temperature. To examine the feasibility of pharmaceutical applications of SFX, a ligand-soaking experiment using thermolysin microcrystals has been performed using SFX. The results were compared with those from a conventional experiment with synchrotron radiation (SR) at 100 K. A protein–ligand complex structure was successfully obtained from an SFX experiment using microcrystals soaked with a small-molecule ligand; both oil-based and water-based crystal carriers gave essentially the same results. In a comparison of the SFX and SR structures, clear differences were observed in the unit-cell parameters, in the alternate conformation of side chains, in the degree of water coordination and in the ligand-binding mode.


Sign in / Sign up

Export Citation Format

Share Document