Measurement of age-dependent radiation ingestion doses due to gross alpha and gross beta exposure from medicinal plants.

This article presents the results of a study conducted to measure the gross alpha, gross beta activities in medicinal plant samples collected from different districts of Azad Kashmir, Pakistan. The ASC-950-DP gasless high-speed counter was used for the measurement of gross α/ß activities. Measured activities have been used to assess age-dependent annual effective doses for infants, one-, five-, ten-, and fifteen-year-old and adult people. For a medicinal plant consumption rate (MPCR) of 1.8 kg a-1, the average gross alpha and beta annual committed effective dose (ACED) delivered to one-, five-, ten-, fifteen-year-olds and adults fall below the WHO recommended level (290 µSv a-1) and that reported in the UNSCEAR 2000 (0.3 mSv a-1) report. Results obtained for the current study show that the radiological hazard related to the consumption of natural radionuclides in medicinal plants is inconsequential with exception of the ACED delivered to infants at an MPCR of 1.8 g a-1 and higher values.

Detection and Quantification of Precious Elements in Astrophyllite Mineral by Optical Spectroscopy.

With many advantages over well-established methods, laser induced breakdown spectroscopy (LIBS) has emerged as a useful analytical technique for the compositional analysis of multi-elemental geological materials. In this study, LIBS was employed for qualitative and quantitative analysis of a rare mineral, astrophyllite, bearing precious elements of industrial and technological interest. The experiment was carried out using second harmonic generation of Nd:YAG laser of pulse width 5 ns and repetition rate of 10 Hz. Microplasma was produced by focusing laser beam on an astrophyllite target, and optical emissions from the generated plasma were recorded in the spectral range of 200-720 nm with the help of a LIBS2000+ detection system. On analyzing the optical spectra, existence of 15 elements in astrophyllite target were revealed. These elements include: Ti, W, Ag, Al, Ba, Ca, Cr, Cu, Fe, Li, Mg, Na, Ni, Si and H. For quantification, calibration-free method was used. Only ten elements, namely Ti, W, Fe, Cr, Cu, Ca, Mg, Ni, Si and Al, were quantified with relative weight concentrations of 55.39%, 18.79%, 18.30%, 4.05%, 2.66, 0.43%, 0.18%, 0.12%, 0.06% and 0.02%, respectively. To benchmark these results, XRF analysis was performed, which confirmed the presence of all the elements detected in the optical spectrum of the sample, except for Na, Li, and H. The concentrations of these ten elements as measured by XRF were in reasonable agreement, especially for the major elements. The presence of a significant amount of Ti and W in an astrophyllite sample, found in Pakistan, highlights the economic value of this mineral. This study may be of further interest in commissioning LIBS technology for exploration of minerals in the region.

A new strategy of using dielectric barrier discharge plasma in tubular geometry for surface coating and extension to biomedical application.

There has always been a quest for nanotechnology to develop inexpensive coating methods with the capability of depositing biocompatible nanomaterials on biomedical and surgical tools. In this mini-report, a plasma-based innovative idea of coating a solid surface with antibacterial/antimicrobial nanosilver is floated and experimentally realized. The desired antibacterial nanosilver was obtained from laser ablation and directly entrained in an outflowing plasma jet, excited in the flow of argon at 10 l min-1 using 20 kV/20 kHz. Under these conditions, the jet can protrude 15 mm deeply into ambient air. The quality of the surface coating can be described by sparsely distributed particles or densely agglomerated clusters, controlled by the plasma length and the surface separation. Apart from the coating, plasma interaction leads to the sterilization of the exposed surface. The idea is essentially important to extend and upscale for coating biomedical and surgical devices in a flexible open processing environment.

Calibration-free laser-induced breakdown spectroscopic analysis of copper-rich mineral collected from the Gilgit-Baltistan region of Pakistan.

In this paper, we present the results of compositional analysis of a copper-rich mineral known as malachite, collected from the Gilgit-Baltistan region of Pakistan. A calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technique is employed for determination of elemental composition of the sample. The study aims at the investigation of the presence of precious elements, if any, in minerals of local origin. The laser beam of a 1064 nm wavelength from a nanosecond pulsed $Q$Q-switched Nd:YAG laser was focused on the surface of the sample, and an emission spectrum was obtained with the help of a LIBS2000 spectrometer covering the spectral range between 200 to 700 nm. Results obtained through analyzing the characteristic emission lines of different elements have confirmed the presence of sixteen (16) elements in the investigated sample, viz. Cu, Si, Al, K, Fe, Mn, Ag, Ti, Ba, Sr, Ca, Mg, Na, Li, C, and H. For quantification of the detected elements in the sample, a calibration-free method based on local thermodynamic equilibrium and optically thin plasma model was employed. Plasma parameters, such as electron number density and temperature, were calculated for the purpose of subsequent calculations. Seven elements, viz. Cu, Fe, Si, Ca, Mg, Mn, and Al, were quantified out of 16 initially detected elements, and their concentration in terms of weight percentage was 43.15%, 20.13%, 18.31%, 9.46%, 3.28%, 3.16%, and 2.51%, respectively. The presence of all seven elements quantified by CF-LIBS was confirmed by x-ray fluorescence analysis.