Quantitative energy-dispersive X-ray fluorescence analysis for unknown samples using full-spectrum least-squares regression

The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.

High-Throughput Powder Diffraction Using White X-Ray Beam and a Simulated Energy-Dispersive Array Detector

High-throughput powder X-ray diffraction(XRD)with white X-ray beam and an energy-dispersive detector array is demonstrated in this work on a CeO;powder sample on a bending magnet synchrotron beamline at the Shanghai Synchrotron Radiation Facility(SSRF),using a simulated energy-dispersive array detector consisting of a spatially scanning silicon-drift detector(SDD).Careful analysis and corrections are applied to account for various experimental hardware-related and diffraction angle-related factors.The resulting diffraction patterns show that the relative strength between different diffraction peaks from energy-dispersive XRD(EDXRD)spectra is consistent with that from angle-resolved XRD(ARXRD),which is necessary for analyzing crystal structures for unknown samples.The X-ray fluorescence(XRF)signal is collected simultaneously.XRF counts from all pixels are integrated directly by energy,while the diffraction spectra are integrated by d-spacing,resulting in a much improved peak strength and signal-to-noise(S/N)ratio for the array detector.In comparison with ARXRD,the diffraction signal generated by a white X-ray beam over monochromic light under the experimental conditions is about 104 times higher.The full width at half maximum(FWHM)of the peaks in q-space is found to be dependent on the energy resolution of the detector,the angle span of the detector,and the diffraction angle.It is possible for EDXRD to achieve the same or even smaller FWHM as ARXRD under the energy resolution of the current detector if the experimental parameters are properly chosen.

Review of the diagnosis of gastrointestinal lanthanum deposition

Lanthanum carbonate is used for treatment of hyperphosphatemia mostly in patients with chronic renal failure.Although lanthanum carbonate is safe,recently,lanthanum deposition in the gastrointestinal mucosa of patients has been reported in the literature.This review provides an overview of gastroduodenal lanthanum deposition and focuses on disease's endoscopic,radiological,and histological features,prevalence,and outcome,by reviewing relevant clinical studies,case reports,and basic research findings,to better understand the endoscopic manifestation of gastrointestinal lanthanum deposition.The possible relationship between gastric lanthanum deposition pattern and gastric mucosal atrophy is also illustrated;in patients without gastric mucosal atrophy,gastric lanthanum deposition appears as diffuse white lesions in the posterior wall and lesser curvature of the gastric body.In the gastric mucosa with atrophy,lanthanum-related lesions likely appear as annular or granular whitish lesions.Moreover,these white lesions are probably more frequently observed in the lower part of the stomach,where intestinal metaplasia begins.

Scanning electron microscopy coupled with energydispersive X-ray spectrometry for quick detection of sulfuroxidizing bacteria in environmental water samples

Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry(EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time(within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples.

Fabrication of GaAs/SiO_(2)/Si and GaAs/Si heterointerfaces by surface-activated chemical bonding at room temperature

The room-temperature(RT)bonding mechanisms of Ga As/Si O_(2)/Si and Ga As/Si heterointerfaces fabricated by surface-activated bonding(SAB)are investigated using a focused ion beam(FIB)system,cross-sectional scanning transmission electron microscopy(TEM),energy dispersive x-ray spectroscopy(EDX)and scanning acoustic microscopy(SAM).According to the element distribution detected by TEM and EDX,it is found that an intermixing process occurs among different atoms at the heterointerface during the RT bonding process following the surface-activation treatment.The diffusion of atoms at the interface is enhanced by the point defects introduced by the process of surface activation.We can confirm that through the point defects,a strong heterointerface can be created at RT.The measured bonding energies of Ga As/Si O_(2)/Si and Ga As/Si wafers are 0.7 J/m^(2)and 0.6 J/m^(2).The surface-activation process can not only remove surface oxides and generate dangling bonds,but also enhance the atomic diffusivity at the interface.

Enhanced K-Edge Radiography Using a High-Spatial-Resolution Cadmium Telluride Array Detector

To confirm the imaging effect of a dual-energy (DE) cadmium telluride (CdTe) array detector (XCounter, Actaeon) and to perform fundamental studies on DE computed tomography, we performed enhanced K-edge radiography using iodine (I) and gadolinium (Gd) media. DE radiography was performed using an X-ray generator with a 0.1-mm-diam-focus tube and a 0.5-mm-thick beryllium window, a 1.0-mm-thick aluminum filter for absorbing extremely low-energy photons, and the CdTe array detector with pixel dimensions of 0.1 × 0.1 mm2. Each pixel has a charge-sensitive amplifier and a dual-energy counter, and the event pulses from the amplifier are sent to the counter to determine two threshold energies. The tube current was a maximum value of 0.50 mA, and the tube voltages for I- and Gd-K-edge radiograms were 60 and 80 kV, respectively. In the I-K-edge radiography of a dog-heart phantom at an energy range of 33 - 60 keV, the muscle density increased, and fine coronary arteries were visible. Utilizing Gd-K-edge radiography of a rabbit head phantom at an energy range of 50 - 80 keV, the muscle density increased, and fine blood vessels in the nose were observed at high contrasts. Using the DE array detector, we confirmed the image-contrast variations with changes in the threshold energy.

Dual-Energy X-Ray Computed Tomography Scanner Using Two Different Energy-Selection Electronics and a Lutetium-Oxyorthosilicate Photomultiplier Detector

To obtain two kinds of tomograms at two different X-ray energy ranges simultaneously, we have constructed a dual-energy X-ray photon counter with a lutetium-oxyorthosilicate photomultiplier detector system, three comparators, two microcomputers, and two frequency-voltage converters. X-ray photons are detected using the detector system, and the event pulses are input to three comparators simultaneously to determine threshold energies. At a tube voltage of 100 kV, the three threshold energies are 16, 35 and 52 keV, and two energy ranges are 16 - 35 and 52 - 100 keV. X-ray photons in the two ranges are counted using microcomputers, and the logical pulses from the two microcomputers are input to two frequency-voltage converters. In dual-energy computed tomography (CT), the tube voltage and current were 100 kV and 0.29 mA, respectively. Two tomograms were obtained simultaneously at two energy ranges. The energy ranges for gadolinium-L-edge and K-edge CT were 16 - 35 and 52 - 100 keV, respectively. The maximum count rate of dual-energy CT was 105 kilocounts per second with energies ranging from 16 to 100 keV, and the exposure time for tomography was 19.6 min.

Using Prostatic Fluid Levels of Some Trace Elements and Their Combinations in Non-Invasive and Highly Accurate Screening for Prostate Cancer

Objective: Prostate specific antigen (PSA) does not provide the high reliability and precision that is required for an accurate screening for prostate cancer?(PCa). The aim of our study was to search for a simple, rapid, direct, preferably non-invasive, and highly accurate biomarker and procedure for the screening for PCa. Method: The levels of trace elements (TE) Br, Fe, Rb, Sr,?and Zn were prospectively evaluated in expressed prostatic fluid (EPF). Also?Zn/Br, Zn/Fe, Zn/Rb, Zn/Sr concentration ratios as well as ZnRb and (ZnRb)/Fe concentration combinations were calculated for EPF samples, obtained from 38 apparently healthy males and from 33, 51, and 24 patients with chronic prostatitis, benign prostatic hyperplasia, and PCa, respectively. Measurements were performed using an energy dispersive X-ray fluorescent (EDXRF) microanalysis. Results: It was found that in the EPF of cancerous prostates the levels of Rb, Zn, Zn/Br, Zn/Fe, Zn/Sr, ZnRb, and (ZnRb)/Fe were significantly lower in comparison with those in the EPF of normal, inflamed, and hyperplastic prostates. For example, in comparison hyperplastic?with cancerous prostates p values obtained using Student’s t-test and?Wilcoxon-Mann-Whitney U-test were Conclusions: The levels of TE and their combinations in EPF, obtained by EDXRF, is a fast, reliable, andnon-invasive diagnostic tool that can be successfully used by local, non- urologist physicians at the point-of-care to provide a highly effective PCa screening and as an additional confirmatory test before a prostate gland biopsy.

Neutron Activation Analysis and Scanning Electron Microscopy of Phytoplankton in the Coastal Zone of Crimea (The Black Sea)

The physiology and ecology of planktonic organisms are influenced by the concentration, chemical speciation and resulting bioavailability of some trace metals. The determination of the elemental structure of phytoplankton is important for interpretation of physiological and functional states of coastal ecosystems. The present study is focused on the structure and elemental composition of the phytoplankton assemblages from the different coastal zones by instrumental neutron activation analysis (INAA), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). For the first time these complementary techniques were simultaneously applied to study the Black Sea phytoplankton. The concentrations of 45 elements in the coastal phytoplankton communities used as bioindicator of inorganic contamination of the Black Sea coastal area near Sevastopol, Ukraine, were determined. Phytoplankton samples were collected by total tows of the plankton net with 35 μm pore size at 3 stations situated in polluted and relatively pristine water areas of the Sevastopol coastal zone during autumn period of the phytoplankton growth. The concentration of Mg, Al, Sc, Ti, V, Mn, As, Rb, Ba, Th and Fe, Cr increases exponentially from relatively pristine station to more polluted station and 10-times and 3-times greater, respectively, in the phytoplankton of the Sevastopol Bay. The rare-earth elements have relatively the same concentration values less than 1 μg/g and tend to accumulate in the phytoplankton from the polluted station in the Sevastopol Bay. The obtained results are in a good agreement with the elemental concentration data in the oceanic plankton, plankton communities from the White Sea and the Black Sea. Using energy-dispersive X-ray spectrometry the mineral particles of unknown origin and impurities of copper (0.42% by weight) in the phytoplankton at the polluted station and zinc (0.57% by weight) at the relatively pristine station were determined.

Study on Properties of Silver Powder for Maki-e

Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. In 2014, there exist only two companies that manufacture silver powder for the purpose of Maki-e, and this study focuses on comparing the powders manufactured by them. Gloss and color of each silver powder were measured after Maki-e decoration was finished, and EDS (energy-dispersive X-ray spectroscopy) was used to determine the differences in their chemical composition. In addition, to verify the effect of polishing, residual gloss after sulfuration and polishing was measured. The study revealed that the shapes of the silver powders (Maru-fun, No. 1) manufactured by the two companies are different and it affects the occupancy rate of Urushi and powder, which in turn affects their gloss and color. Wakou silver has a very strong resistance to sulfuration;however, owing to its Pd content, its chroma is much lower than that of other powders. It was shown that sulfuration on powder surface can be removed by polishing irrespective of the shape and chemical composition ratio of the particles.

Nanoencapsulation of arsenate with nanoscale zero-valent iron(nZVI):A 3D perspective

The principal forces driving the efficient enrichment and encapsulation of arsenic(As) into nanoscale zero-valent iron(nZVI) are the disordered arrangement of the atoms and the gradient chemical potentials within the core-shell interface. The chemical compositions and the fine structure of nZVI are characterized with a combination of spherical aberration corrected scanning transmission electron microscopy(Cs-STEM), X-ray energy-dispersive spectroscopy(XEDS), electron energy loss spectroscopy(EELS), and high-resolution X-ray photoelectron spectroscopy(HR-XPS). Atomically resolved EELS at the oxygen K-edge unfolds that the Fe species in nZVI are well stratified from Fe(Ⅲ) oxides in the outermost periphery to a mixed Fe(Ⅲ)/Fe(Ⅱ) interlayer, then Fe(Ⅱ) oxide and the pure Fe(0) phase. Reactions between As(Ⅴ)and nZVI suggest that a well-structured local redox gradient exists within the shell layer, which serves as a thermodynamically favorable conduit for electron transfer from the iron core to the surface-bound As(Ⅴ). HR-XPS with ion sputtering shows that arsenic species shift from As(Ⅴ), As(Ⅲ)/As(Ⅴ) to As(Ⅴ)/As(Ⅲ)/As(0) from the iron oxide shell–water interface to the Fe(0) core. Results reinforce previous work on the efficacy of nZVI for removing and remediating arsenic while the analytical TEM methods are also applicable to the study of environmental interfaces and surface chemistry.

Growth and optical properties of InxGa1-xP nanowires synthesized by selective-area epitaxy

Ternary III-V nanowires （NWs） cover a wide range of wavelengths in the solar spectrum and would greatly benefit from being synthesized as position-controlled arrays for improved vertical yield, reproducibility, and tunable optical absorption. Here, we report on successful selective-area epitaxy of metal-particle-free vertical InxGa1-xP NW arrays using metal-organic vapor phase epitaxy and detail their optical properties. A systematic growth study establishes the range of suitable growth parameters to obtain uniform NW growth over a large array. The optical properties of the NWs were characterized by room-temperature cathodoluminescence spectroscopy. Tunability of the emission wavelength from 870 nm to approximately 800 nm was achieved. Transmission electron microscopy and energy dispersive X-ray measurements performed on cross- section samples revealed a pure wurtzite crystal structure with very few stacking faults and a slight composition gradient along the NW growth axis.

Partitioning of nitrogen atoms and its effect on retained austenite content in an ultra-low-carbon Cr-Mn-N stainless steel

The partitioning of nitrogen atoms and its effect on the retained austenite content(RAC)during quenching and partitioning(Q&P)process were investigated by dilatometry,X-ray diffraction,and field emission transmission electron microscopy with energy-dispersive spectrometer mapping in a 00Cr13Mn8N steel.Nitrogen partitioning by diffusion of N atoms from martensite to austenite occurred at 400℃after quenching.N atoms are enriched in austenite after partitioning,and the stability of these N-rich austenite is improved and retained at room temperature during subsequent cooling.The different quenching temperatures(QTs)result in different phase fractions after partitioning.With the increase in QT,RAC first increases and then decreases,and the maximum RAC is 28.5 vol.%after quenching at 80℃.A mathematical model was developed to rapidly and accurately characterize the phase fraction in Q&P process based on the relative length change of the samples partitioned after quenching at different QTs.

Clustering analysis of ancient celadon based on SOM neural network

In the study, chemical compositions of 48 fragments of ancient ceramics excavated in 4 archaeological kiln sites which were located in 3 cities (Hangzhou, Cixi and Longquan in Zhejiang Province, China) have been examined by energy-dispersive X-ray fluorescence (EDXRF) technique. Then the method of SOM was introduced into the clustering analysis based on the major and minor element compositions of the bodies, the results manifested that 48 samples could be perfectly distributed into 3 locations, Hangzhou, Cixi and Longquan. Because the major and minor element compositions of two Royal Kilns were similar to each other, the classification accuracy over them was merely 76.92%. In view of this, the authors have made a SOM clustering analysis again based on the trace element compositions of the bodies, the classification accuracy rose to 84.61%. These results indicated that discrepancies in the trace element compositions of the bodies of the ancient ceramics excavated in two Royal Kiln sites were more distinct than those in the major and minor element compositions, which was in accordance with the fact. We argued that SOM could be employed in the clustering analysis of ancient ceramics.

Occurrence, Structure and Mineral Phases of Nanoparticles in an Anthrosol

Soils contain various kinds of crystalline to amorphous solid particles with at least one dimension in the nanoscale （〈 100 nm）. These nanoparticles contribute greatly to dynamic soil processes such as soil genesis, trace element cycling, contaminant transport, and chemical reaction. The nano-sized fraction of an Anthrosol was obtained to determine the occurrence, chemical composition, structure, and mineral phases of nanoparticles using high-resolution transmission electron microscopy （HRTEM） equipped with an energy-dispersive X-ray spectroscopy. Selected area electron diffraction or the fast Fourier transform of high-resolution images was used in structural characterization of the nanoparticles with HRTEM. Two nanoscale mineral types, i.e., mineral nanoparticles and nanomi- nerals, were observed in the Anthrosol. Mineral nanoparticles in soil included well crystalline aluminumsilicate nanosheets, nanorods, and nanoparticles. Nanosheets with a length of 120-150 nm and a width of about 10-20 nm were identified as chlorite/vermiculite series. The presence of clear lattice fringe spacing in HRTEM image of nanoparticles indicated that mineral nanoparticles had a relatively good crystallinity. The nanomineral ferrihydrite also existed in the Anthrosol. The HRTEM images and the particle size distribution histogram suggested that these ferrihydrite nanoparticles were quite homogeneous, and had a narrow size distribution range （1-7 nm） with a mean diameter of 3.6 4- 1.6 nm. Our HRTEM observation indicated that mineral nanoparticles and nanominerals were common and widely distributed in Anthrosols. HRTEM and selected area diffraction or lattice fringe spacing characterization provided further proofs to the structure of nanoparticles formed in soil.

Significance of trace element quantities in the prostatic secretion of patients with benign prostatic hyperplasia and prostate cancer

Aim:Benign prostatic hyperplasia and prostate cancer is an internationally important health problem of the man,particularly in developed countries.The aim of this exploratory study was to evaluate whether significant difference in the levels of Zn and some other trace elements of prostatic fluid exist between the inflamed and malignantly transformed prostate.Methods:Prostatic fluid levels of Br,Fe,Rb,Sr,and Zn were prospectively evaluated in 52 patients with benign prostatic hyperplasia and 24 patients with prostate cancer.Measurements were performed using 109Cd radionuclide-induced energy dispersive X-ray fluorescent microanalysis.Prostatic fluid samples were divided into two portions.One was used for cytological study to exclude prostatitis,while the other was intended for trace element analysis.Results:Mean values±standard error of means for concentration(mg/L)of trace element in the prostatic fluid of hyperplastic prostate were:Br 2.32±0.30,Fe 11.5±1.8,Rb 1.70±0.23,Sr 1.41±0.26,and Zn 488±42.The contents of Rb and Zn were significantly lower(approximately 3.2 and 7.7 times,respectively)in fluid of cancerous prostate compared with those in fluid of hyperplastic prostate.Conclusion:There are significant differences in trace element contents in the fluid of hyperplastic and malignantly transformed prostate.The great decrease in levels of Rb and Zn in the fluid of cancerous prostate might demonstrate ;an involvement of these trace elements in etiology and pathogenesis of malignant prostate tumors.It was supposed that the differences in Rb and Zn levels in prostatic fluid can be used as tumor markers.