Feasibility of a simple laser-induced breakdown spectroscopy (LIBS) device has been investigated for the analysis of Mg and Ca in edible salts. The LIBS spectrometer was assembled with a compact low-power diode-pumped solid-state laser (DPSSL) and a non-gated low-resolution handheld spectrometer. A simple sampling process was employed for on-site application. A piece of filter paper was dipped in the aqueous solution of a sample salt and dried for analysis using LIBS. Maintaining the sample surface height at the optimum position was critical to generate plasmas persistently due to the low pulse energy of the DPSSL. The varying height of the filter paper surface was monitored and compensated, while the sample stage was translated to collect spectra from different positions. The variation of line intensities of Mg and Ca could be attributed to the inhomogeneous distribution of dry residues. To correct this, the peak that consists of the Na(I) and C(II) lines at 568 nm was employed as a reference signal for intensity normalization of the analyte Mg(II) and Ca(II) lines. For edible salt products, the normalized Mg(II) and Ca(II) line intensities could be well correlated with the concentrations of Mg and Ca determined using inductively coupled plasma optical emission spectroscopy. Our results indicate that a simple LIBS device in combination with the simple sampling method is promising as an on-site salt quality assessment methodology.

Smoking is a severe addictive health risk behavior and notorious for the high likelihood of relapse after attempted cessation. Such an addictive pattern in smoking has been associated with neurobiological changes in the brain. However, little is known whether the neural changes associated with chronic smoking persist after a long period of successful abstinence. To address this question, we examined resting state EEG (rsEEG) in heavy smokers who have been smoking for 20 years or more, past-smokers who have been successfully abstaining for 20 years or more, and non-smokers. Compared with chronic current- or past- smokers, non-smokers showed higher relative power in theta frequency band, showcasing long-lasting effects of smoking on the brain. A few rsEEG features in alpha frequency band also revealed reversible impacts of smoking, such that only current-smokers, but not past-smokers, showed distinctively higher patterns than non-smokers in their relative power, EEG reactivity—power changes between eyes-closed and eyes-open conditions—, and coherence between channels. Furthermore, rsEEG feature differences between current- and past- smokers were accounted for by individuals' self-reported smoking history and nicotine dependence. These data suggest long-lasting impacts of chronic smoking on the brain that are dissociable from the neural changes reversible with long-term abstinence.

Smoking is a severe addictive health risk behavior and notorious for the high likelihood of relapse after attempted cessation. Such an addictive pattern in smoking has been associated with neurobiological changes in the brain. However, little is known whether the neural changes associated with chronic smoking persist after a long period of successful abstinence. To address this question, we examined resting state EEG (rsEEG) in chronic smokers who have been smoking for 20 years or more, past-smokers who have been successfully abstaining for 20 years or more, and never-smokers. Both current-smokers and past-smokers showed significantly decreased relative theta power than never-smokers, showcasing persistent effect of smoking on the brain. Other rsEEG features in alpha frequency band demonstrated distinctive patterns associated with active smoking, such that compared to never-smokers, only current-smokers, but not past-smokers, showed significantly higher relative power, EEG reactivity—power changes between eyes-closed and eyes-open conditions—, and coherence between channels. Furthermore, individual variabilities across these rsEEG biomarkers were accounted for by individuals’ self-reported smoking history and nicotine dependence in current- and past- smokers. These data suggest the persistent effect of smoking on the brain even after sustained remission for 20 years.