Suitability and Applications of Total-Reflection X-Ray Fluorescence Spectrometry for Analytical Characterization of Nuclear Materials.

The suitability and applications of Total reflection X-ray Fluorescence (TXRF) for characterization of nuclear materials are numerous. TXRF has been successfully applied for trace, minor and major determinations of constituents in nuclear materials such as fuel, clad, control rod, coolant, etc. The two major advantages of TXRF i.e. requirement of very small sample for analysis and non-requirement of matrix matched standards, make this technique further more attractive and suitable for nuclear industry. The applications of TXRF for trace analysis in nuclear materials such as fuel, clad, coolant and control rods are described in detail along with its applications for determination of major and speciation studies in TXRF mode.

Total Reflection X-ray Fluorescence Spectrometric Analysis of Ten Lanthanides at the Ultratrace Level Having a High Degree of Overlap in the Emission Lines.

The extensive use of lanthanide elements in the medical, electrical, agricultural, and nuclear fields has increased their contamination in the environment. The detrimental effect of lanthanides on human health can be reduced or eliminated by their fast determination in the concerned specimen. For this purpose, an offline conjugation of the cloud point extraction (CPE) process with total reflection X-ray fluorescence (TXRF) spectrometry was done. This process was found to provide simple, quick, and precise simultaneous determination of ten lanthanides whose emission lines have a high degree of overlap at the ultratrace level. N,N,N',N'-tetra-octyl-diglycolamide in triton X-114 micelles was found to offer a selective CPE of all of the lanthanides in the presence of higher concentrations of naturally abundant cations and anions. A multivariative partial least-squares regression (PLSR) calibration approach was preferred due to the complex overlapped spectra of L lines of the lanthanides. Ten lanthanides, viz., La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, and Lu, were simultaneously determined by this method, having concentrations in the range from 10 to 5 × 103 µg L-1. The proposed method was validated by analyzing three certified reference materials (CRMs), viz., NASS-7 seawater, SRLS-6 river water, and NIST 1640a natural water, via standard addition with the relative standard deviations of ≤10%.

A highly sensitive method for uranium quantification in water samples at ultra-trace level by total reflection X-ray fluorescence, after its direct pre-concentration on the surface of amidoxime functionalized quartz sample supports.

In this work we have developed a Total reflection X-Ray Fluorescence (TXRF) based methodology for the determination of uranium in natural water samples at ultra-trace concentration level. The methodology involves functionalization of quartz sample supports used for TXRF measurements with (3-Amidoxy) triethoxysilane, which has very high uranium uptake efficiency. (3-Amidoxy) triethoxysilane has been synthesized from (3-Cyanopropyl) triethoxysilane (CPTS). This amidoxime functionalized sample supports, simply needed to be dipped in the uranium solution for 3 h after which, it can be directly taken for TXRF measurements. The developed methodology is very fast, simple with less sample preparation steps involved. The present work utilizes Rayleigh scattered peak to construct the calibration curve for the quantification purpose. The developed methodology has improved accuracy as well as precision for the quantification of uranium at such low concentrations level. The detection limit and accuracy obtained are 0.013 ng/mL (13 ppt) and 1.9%, respectively which are the lowest using any X-Ray Fluorescence based method, to the best of our knowledge. The method was successfully applied for the U determination in natural water samples like ground water, river water and sea water.

Direct non-destructive trace and major elemental analysis in steel samples utilizing micro-focused bremsstrahlung radiation in X-ray fluorescence geometry.

Stainless steel is a very important technological material used in various industries. In this work, a simple non-destructive method is developed for major as well as trace elemental determination in stainless steel samples using micro-X-ray fluorescence (XRF) based technique. The utilization of full bremsstrahlung excitation in combination with micro-focused geometry substantially reduces the detection limit of different elements present in stainless steel. The developed methodology is capable of determining elemental concentrations down to 30-80 ppm level in stainless steel matrix without any requirement of cumbersome dissolution or separation procedure. Elements such as Si, P, S and Co were determined simultaneously at trace level using the developed micro-XRF based technique. At the same time this technique is also capable of analyzing elements which are present at percentage levels. Till now there is no such report showing the capability of lab-XRF based non-destructive technique for the analysis of both major as well trace elements down to such low concentration level to the best of our knowledge. Moreover, the methodology involved is very simple and straight forward. The analytical results obtained were very much satisfactory with good accuracy and precision.

Piperazinyl-Based Diamide Ligand for Selective Precipitation of Actinyl (UO22+/PuO22+) Ions with Fast Kinetics.

A novel ligand N,N'-bis(N″,N″-diethyl carbamoyl) piperazine (BDECP), L1, is synthesized as a selective precipitant for hexavalent actinyl (UO22+ and PuO22+) ions from an aqueous nitric acid medium. The ligand BDECP forms an infinite one-dimensional coordination polymer with uranyl nitrate and behaves as a bridging bidentate neutral donor. There is an alternate repetition of [UO2(NO3)2] and BDECP units as evidenced by single-crystal X-ray diffraction. Uranyl ion (UO22+) can be precipitated in >99% yield from an aqueous nitric acid medium. L1 shows fast kinetics of precipitation of uranyl ion as compared to those of other reported ligands like N-alkyl pyrolidone and N-(1-adamantyl) acetamide. Avrami's coefficient, obtained from the Avrami-Erofe'ev equation, shows that the precipitation mechanism is controlled by the phase boundary and not governed by diffusion. Theoretical studies of the uranyl complex of L1 show that there is no thermodynamic preference for L1 as compared to other potential amide-based precipitants. The principal factors that govern the fast kinetics of precipitation are the aqueous solubility and higher charge density on the amide oxygen of L1.

Direct non-destructive total reflection X-ray fluorescence elemental determinations in zirconium alloy samples.

The development of a direct non-destructive synchrotron-radiation-based total reflection X-ray fluorescence (TXRF) analytical methodology for elemental determinations in zirconium alloy samples is reported for the first time. Discs, of diameter 30 mm and about 1.6 mm thickness, of the zirconium alloys Zr-2.5%Nb and Zircalloy-4 were cut from plates of these alloys and mirror polished. These specimens were presented for TXRF measurements directly after polishing and cleaning. The TXRF measurements were made at the XRF beamline at Elettra synchrotron light source, Trieste, Italy, at two different excitation energies, 1.9 keV and 14 keV, for the determinations of low- and high-Z elements, respectively. The developed analytical methodology involves two complementary quantification schemes, i.e. using either the fundamental parameter method or relative sensitivity based method, allowing quantification of fifteen minor and trace elements with respect to Zr with very good precision and accuracy. In order to countercheck the TXRF analytical results, some samples were analyzed using the DC arc carrier distillation atomic emission spectrometry technique also, which shows an excellent agreement with the results of the TXRF-based methodology developed in this work. The present work resulted in a non-destructive TXRF elemental characterization methodology of metal and alloy samples avoiding the cumbersome dissolution and matrix separation which are normally required in other techniques and traditional methods of TXRF determination. In addition, the production of analytical waste could also be avoided to a large extent. Although the work was carried out for specific applications in the nuclear industry, it is equally suitable for other such samples in different industrial applications.

Universal EDXRF Method for Multi-elemental Determinations Using Fused Bead Specimens.

A systematic study on the EDXRF determination of multi-elements using fusion bead specimens and a universal calibration procedure was carried out. Beads of multi-elements were prepared by mixing MERCK multi-elemental standard solutions with the fusion flux. The elemental X-ray lines of K, Ca, Ba, Cr, Mn, Fe, Co, Ni, Cu and Zn were excited using a Ge secondary target and that of Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Pb, Bi and Sr using a Rh primary target. The relative sensitivities of the elemental X-ray lines obtained using different excitation modes were calculated using a single bead. Using this relative sensitivity, the concentration of elements in other bead samples was determined. The average precision obtained was 3% (1 s) and the average deviation from expected values, calculated on the basis of sample preparation, was 6%. In order to further countercheck the validity of this methodology, a standard soil sample received from IAEA was analyzed.

Direct Multielemental Trace Determinations in Plutonium Samples by Total Reflection X-ray Fluorescence Spectrometry Using a Very Small Sample Amount.

A simple, safe, and sensitive method for direct multielemental trace determinations in plutonium samples using total reflection X-ray fluorescence (TXRF) spectrometry has been developed. A very small volume (2 µL) of the sample solutions was deposited on TXRF supports after separation of the plutonium matrix from these solutions. Since the amount of the plutonium deposited on the supports was in the ng level only fixed on the supports and the specimen spots were not disturbed during the sample preparation, the samples could be analyzed directly without putting the instrument in a glovebox. This approach avoided a cumbersome operation of the instrument in a glovebox, which is normally utilized for Pu-based samples using other techniques. Similarly, the requirement of small amounts of the samples minimized the radiation dose to the operator as well as a cumbersome problem of management of radioactive analytical waste of plutonium samples. The samples were analyzed using the TXRF spectra of the specimens, concentration of the internal standard Se or Ga and predetermined sensitivity values. The elemental detection limits for the elements K-Sr varied from 1.06 to 0.09 ng. The elements K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Ba, Tl, and Pb were analyzed at µg/mL level. The analytical results of TXRF determinations showed average relative standard deviation (RSD) value of 4.5% (1σ, n = 3) and the TXRF determined results deviated from the expected values by 5.9% on average for samples prepared by adding multielements in plutonium solutions. Two real plutonium samples were also analyzed in similar manner. For the real plutonium sample solution the average RSD values of TXRF determinations were 10.6% (1σ, n = 3) for the elemental concentrations in the range of 0.2 to 61 µg/mL. These values are comparable with conventional trace element analytical techniques with added advantages mentioned above.

Selective Micellar Extraction of Ultratrace Levels of Uranium in Aqueous Samples by Task Specific Ionic Liquid Followed by Its Detection Employing Total Reflection X-ray Fluorescence Spectrometry.

A task specific ionic liquid (TSIL) bearing phosphoramidate group, viz., N-propyl(diphenylphosphoramidate)trimethylammonium bis(trifluoromethanesulfonyl)imide, was synthesized and characterized by 1H NMR, 13C NMR, 31P NMR, and IR spectroscopies, elemental (C H N S) analysis, and electrospray ionization mass spectrometry (ESI-MS). Using this TSIL a cloud point extraction (CPE) or micelle mediated extraction procedure was developed for preconcentration of uranium (U) in environmental aqueous samples. Total reflection X-ray fluorescence spectrometry was utilized to determine the concentration of U in the preconcentrated samples. In order to understand the mechanism of the CPE procedure, complexation study of the TSIL with U was carried out by isothermal calorimetric titration, liquid-liquid extraction, 31P NMR and IR spectroscopies, and ESI-MS. The developed analytical technique resulted in quantitative extraction efficiency of 99.0 ± 0.5% and a preconcentration factor of 99 for U. The linear dynamic range and method detection limit of the procedure were found to be 0.1-1000 ng mL-1 and 0.02 ng mL-1, respectively. The CPE procedure was found to tolerate a higher concentration of commonly available interfering cations and anions, especially the lanthanides. The developed analytical method was validated by determining the concentration of U in a certified reference material, viz., NIST SRM 1640a natural water, which was found to be in good agreement at a 95% confidence limit with the certified value. The method was successfully applied to the U determination in three natural water samples with ≤4% relative standard deviation (1σ).

Direct Determination of Oxidation States of Uranium in Mixed-Valent Uranium Oxides Using Total Reflection X-ray Fluorescence X-ray Absorption Near-Edge Spectroscopy.

Total reflection X-ray fluorescence (TXRF)-based X-ray absorption near-edge spectroscopy has been used to determine the oxidation state of uranium in mixed-valent U3O8 and U3O7 uranium oxides. The TXRF spectra of the compounds were measured using variable X-ray energies in the vicinity of the U L3 edge in the TXRF excitation mode at the microfocus beamline of the Indus-2 synchrotron facility. The TXRF-based X-ray absorption near-edge spectroscopy (TXRF-XANES) spectra were deduced from the emission spectra measured using the energies below and above the U L3 edge in the XANES region. The data processing using TXRF-XANES spectra of U(IV), U(V), and U(VI) standard compounds revealed that U present in U3O8 is a mixture of U(V) and U(VI), whereas U in U3O7 is mixture of U(IV) and U(VI). The results obtained in this study are similar to that reported in literature using the U M edge. The present study has demonstrated the possibility of application of TXRF for the oxidation state determination and elemental speciation of radioactive substances in a nondestructive manner with very small amount of sample requirement.

Assessment and management of musculoskeletal disorders among patients living with HIV.

HIV is a global pandemic. However, anti-retroviral therapy has transformed the prognosis and, providing compliance is good, a normal life expectancy can be anticipated. This has led to increasing numbers of people with chronic prevalent, treated infection living to older ages. Musculoskeletal pain is commonly reported by HIV patients and, with resumption of near-normal immune function, HIV-infected patients develop inflammatory rheumatic diseases that require assessment and management in rheumatology clinics. Moreover, it is becoming apparent that avascular necrosis and osteoporosis are common comorbidities of HIV. This review will contextualize the prevalence of musculoskeletal symptoms in HIV, informed by data from a UK-based clinic, and will discuss the management of active inflammatory rheumatic diseases among HIV-infected patients taking anti-retroviral therapy, highlighting known drug interactions.

Investigations on local structures in new Bi2-2xLa2xUO6 (x = 0-0.05) solid solutions: a combined XRD, EXAFS, PL and EPR study.

La doped Bi2UO6 solid solutions of the general formula Bi2-2xLa2xUO6 (x = 0-0.05) were prepared by the solid state reaction of Bi2O3, La(OH)3 and U3O8 in a stoichiometric ratio. These solid solutions were characterized by X-ray diffraction, Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Spectroscopy (XANES) studies. It was found that La goes to the Bi sites of the Bi2UO6 lattice during the formation of these solid solutions. For further confirmation, a photoluminescence (PL) study on an iso-structural Bi1.96Eu0.04UO6 was performed, and this supports the above observation. The solid solutions were also probed by EPR studies. The PL and EPR studies suggest that there are doping induced oxygen vacancies in these solid solutions.

Photoluminescence and EPR studies on Fe³âº doped ZnAl2O4: an evidence for local site swapping of Fe³âº and formation of inverse and normal phase.

Considering that ZnAl2O4 spinel has two different sites (octahedral and tetrahedral) and its properties change with dopant ion distribution among these two sites; ZnAl2O4 doped with varied concentrations of Fe(3+) was synthesized by a low temperature sol-gel combustion method. Phase purity and structural investigations were carried out using Rietveld refined X-ray diffraction which shows a decrease in the value of cell parameters at higher doping levels. Photoluminescence (PL) and electron paramagnetic resonance (EPR) studies have shown that on doping, Fe(3+) ions were distributed in both tetrahedral and octahedral sites. At octahedral sites, Fe(3+) exhibited a broad red emission around 745 nm while at tetrahedral sites it exhibited well-defined vibronic sidebands at 665, 674, 684 and 693 nm along with a broad blue band with a maxima at 445 nm at room temperature. EPR studies have shown a broad spectrum at g ≈ 2.2 which corresponds to the Fe(3+) in octahedral sites, while the broad signal at g ≈ 4.2 belongs to Fe(3+) in tetrahedral sites. It was also inferred from these studies that Fe(3+) prefers to occupy octahedral sites at higher concentrations and at higher annealing temperatures. The PL decay behavior of Fe(3+) in ZnAl2O4 has also shown that two different types of Fe(3+) ions were present in this matrix. The first type was a long lived species (τ ≈ 170 µs) present at octahedral sites and the other was a short lived species (τ ≈ 40 µs) present at the tetrahedral sites; the fraction of the long lived species predominate at higher concentrations. Thus the present work is mainly focused on understanding the tuning of local site occupancy of the dopant ion among those sites with varying concentration and annealing temperature, using the dopant ion itself as a spectroscopic probe, which further helps in understanding the phase (inverse and normal) of the spinel.

Lung carcinosarcoma as a rare biphasic sarcomatoid carcinoma: a case report.

INTRODUCTION: A fit, 57-year-old man admitted with chest pain and haemoptysis turned out to have a primary tumour in the left lung. CASE PRESENTATION: In this 57-year-old Caucasian man, the diagnosis followed a computed tomography scan and histopathological evidence gained post-resection. The biopsy showed a uniform, spindle shape with focal pleomorphism which was suggestive of lung carcinosarcoma. CONCLUSIONS: The authors report this case in literature and discuss how a rare malignant tumour can be found in those presenting with trivial chest symptoms.

Nocardia - Opportunistic chest infection in elderly: A case report.

In this rare case a non-immunocompromised patient with old Tuberculosis on low dose of steroids presents with opportunistic infection of a weakly aerobic gram positive acid fast, filamentous bacteria called Nocardia.An 80 year old non-smoking white female presented with cough, shortness of breath and purulent sputum.Initial antibiotics given were not helpful. Later microbial diagnosis was Nocardia in sputum sample which was uncommon in a non-immunocompromised. She responded to co-trimoxazole therapy.