Search

An iodine-iodide system was investigated as an alternative lixiviant for HNO3 for leaching precious metals from the end-of-life c-Si photovoltaic (PV) cell. A series of batch experiments were conducted for the optimization of leaching kinetics and thermodynamic equilibrium followed by a life cycle assessment (LCA) using data from the experiments. The results showed that more than 95% of Ag and Al leached out within the first 5 min. The optimum conditions for equilibrium leaching were as follows: solid to liquid ratio of 1:10 for Ag (1:9 ml for Al), and I2 concentration of 0.35 M for Ag (0.3 M for Al), with I- concentration of 0.7 M. In addition, selective leaching of Ag could also be accomplished by adjusting the reaction pH to 9.6%, and 93% of reproducibility was achieved via the rejuvenation of the exhausted leaching solution, which can benefit the subsequent recovery process. The leaching efficiency of iodine-iodide system was nearly comparable to that of HNO3, and the environmental impacts of the two cycle of continuous process with rejuvenation of the iodine leaching solution can be effectively reduced especially in the acidification & eutrophication, respiratory effect, and mineral extraction categories with subsequent exclusion of the additional neutralization process.

External intercostal muscle is considered as an inspiratory muscle. Its electromyographic (EMG) activity is exquisitely sensitive to proprioceptive afferents and is predominant in zones with the greatest respiratory effect. In the current series of studies, we assessed the contribution of segmental reflexes to this particular distribution of activity in anesthetized rabbits. We first established a parallel between gradients of activity and mechanical advantage. The sensitivity of external intercostal EMG activity to rib displacement was then assessed in the 3rd and 5th interspaces and in the dorsal, middle and ventral muscle bundles of the 3rd interspace. Finally, persistence of the dorso-ventral gradient was tested after a dorsal rhizotomy (interspaces 3-5). There were no differences in the sensitivity to rib motion in the studied positions. After rhizotomy, the dorso-ventral gradient of activity persisted at rest and with inspiratory resistive loading. We, therefore, conclude that the neuromechanical matching of respiratory drive in the external intercostal muscles is not the result of segmental reflexes.

The respiratory effect of diagnostic colonoscopy and upper endoscopy were studied in 32 elderly patients. Twenty-two underwent colonoscopy and 10 upper endoscopy. In the group undergoing upper endoscopy, 4 of 10 patients experienced a decrease in oxygen desaturation greater than or equal to 4% during the medication period; an additional 2 patients desaturated during the procedure. In the group undergoing colonoscopy, 12 of 22 patients experienced oxygen desaturation during the medication period; 3 other patients desaturated during the procedure. Mean SaO2 for each group was lowest (p less than 0.05) during the medication period. Central apneas occurred in 13 of the patients undergoing colonoscopy during the medication period; however, only 8 of these patients with apneas experienced desaturation greater than or equal to 4% and the periods of desaturation did not correlate with the periods of apneas. Oxygen desaturation greater than or equal to 4% occurs frequently during both upper endoscopy and colonoscopy in this elderly population. This is related to the effects of sedation; the procedure itself worsened the desaturation in only 16% of the patients. Furthermore, the desaturation did not correlate with changes in the breathing patterns of the patients. Low-flow oxygen and/or close monitoring of patients during and subsequent to administration of medication is advised.

Over a five-year period a consistent habit of smoking or nonsmoking was maintained by 302 women (aged 25 to 54 years at the beginning of the study). There were 130 nonsmokers, 40 ex-smokers, and 15 light, 46 moderate, and 71 heavy smokers. Smokers without serious disability who had stopped smoking had a very low prevalence of respiratory symptoms and showed worsening of pulmonary function over the years similar to life-long nonsmokers. Although there is a dose-related response to cigarettes, individual susceptibility also plays an important role in determining the respiratory effect of smoking. A range for change in ventilatory function over a five-year period in apparently healthy nonsmoking women is provided. Using this range, it is possible to identify susceptible smokers who show deterioration in ventilatory function that is more rapid than normal. Repeated spirometric studies may be useful in selecting a group at greatest risk of developing later disabling chronic obstructive pulmonary disease.

Advances in knowledge concerning red tide toxin aerosols (airborne) of the Florida red tide organism, Ptychodiscus brevis, have not kept pace with information about waterborne toxins. This review provides a summary of current knowledge regarding the characterization, effect and production of red tide toxin aerosols. Insight into the chemical characterization and toxic effects of aerosolized toxins is provided from investigations of toxins extracted from natural blooms, as well as from laboratory cultures, of P. brevis. This information is used in conjunction with the few studies that have been performed on toxin aerosols to consider toxic effects. The production of aerosolized toxins is considered through studies of jet drop aerosol formation from bursting bubbles. Existing information suggests that aerosolized red tide toxins may be the same chemicals as those extracted from laboratory cultures, with one of the toxins having a greater respiratory effect than others.

The aerometric results indicate significant differences between the annual means for SO2 and NO2 with the Seiberling school having the higher values. The questionnaire results indicate that the Seiberling children reported more wheezing in the chest, and shortness of breath than the Betty Jane children. Daily symptoms reported by the students indicate that the Seiberling children reported twice as many incidences of upper respiratory symptoms including rhinitis, cough, and sore throat. Baseline asymptomatic lung function testing did show that the ratio FEV1/FVC was significantly lower at the Seiberling school. For both schools there was a decrease in lung function during the symptomatic phase of an acute respiratory illness (AR!), and the tests further indicate that the ARIs in the Seiberling school were more severe and/or involved the small airways more so than the ARIs at the Betty Jane school. Recovery from the ARIs were not complete after nine days with the Seiberling children showing slower recovery than the Betty Jane children. On the basis of available aerometric information it is suggested that SO2 in combination with NO2 is primarily responsible for the reduction in lung function tests and the exacerbations seen in the children at the Seiberling school.