Cocaine does not compromise cerebral or myocardial oxygen delivery in fetal sheep

Aprikalim, a K+ ATP channel opener, is a potent vasodilator with demonstrated cardioprotective properties against ischemia/reperfusion injury. It is still unknown if K+ ATP channel openers exert their beneficial effects via interaction with oxygen-derived free radicals. Therefore, we investigated the cardioprotective effects of aprikalim against oxygen-derived free radicals. Isolated rabbit hearts were perfused at constant pressure (85 cm H2O) or constant flow (30-35 ml/min). Heart rate, left ventricular developed pressure (LVDP), and either coronary flow or coronary perfusion pressure (CPP) were monitored. Free radicals were produced by electrolysis of the perfusate (0.6 mA, direct current), and 10 microM aprikalim was infused before and after exposure to free radicals. In the constant perfusion pressure experiments, 10 min of exposure to free radicals resulted in a significant reduction of heart rate (137 to 129 beats/min), LVDP (112 to 91 mmHg) and coronary flow (37 to 29 ml/min); coronary flow was more markedly impaired than contractile function. Acetylcholine-induced coronary dilation was also significantly attenuated in the presence of free radicals. After 30 min of recovery, both coronary flow and LVDP were still significantly decreased while acetylcholine-induced coronary dilation had fully recuperated. Aprikalim completely abated the coronary and cardiac depressant actions of free radicals. Constant flow experiments indicated that exposure to free radicals increased CPP (+40%, p < 0.05), an effect totally suppressed by aprikalim. These results demonstrate that aprikalim reverses the cardiodepressant actions of free radicals. The cardioprotection it afforded involves both contractile function and the coronary vasculature. Acetylcholine-induced coronary dilation was blunted by free radicals, an indication of complex interactions at the coronary endothelial level.     

Some chemical and physical properties of tailings water from oil sands extraction plants

We have carried out quantitative analyses of dissolved sodium, potassium, calcium, magnesium, chloride, carbonate, bicarbonate, ‘alkalinity’, sulphate, aluminum, iron, and silicon in tailings water from the GCOS tailings pond and from the Syncrude pilot plant. Surface tensions of these waters have been measured over a range of pH values, and effects of added Mg²⁺ and Ca²⁺ ions on surface tension have been investigated. Some similar measurements have been made on ‘synthetic pond water’. Infrared and proton n.m.r. measurements have been made on the organic material extracted from GCOS pondwater. This information on tailings water is relevant to the large accumulation of tailings that has become known as the ‘pondwater problem’ in connection with extraction of bitumen from mined Alberta oil sands.     

A machine-learning approach to forecasting remotely sensed vegetation health

Drought threatens food and water security around the world, and this threat is likely to become more severe under climate change. High-resolution predictive information can help farmers, water managers, and others to manage the effects of drought. We have created an open-source tool to produce short-term forecasts of vegetation health at high spatial resolution, using data that are global in coverage. The tool automates downloading and processing Moderate Resolution Imaging Spectroradiometer (MODIS) data sets and training gradient-boosted machine models on hundreds of millions of observations to predict future values of the enhanced vegetation index. We compared the predictive power of different sets of variables (MODIS surface reflectance data and Level-3 MODIS products) in two regions with distinct agro-ecological systems, climates, and cloud coverage: Sri Lanka and California. Performance in California is higher because of more cloud-free days and less missing data. In both regions, the correlation between the actual and model predicted vegetation health values in agricultural areas is above 0.75. Predictive power more than doubles in agricultural areas compared to a baseline model.     

Developing non-interactive MPC with trusted hardware for enhanced security

International Journal of Information Security - Secure multiparty computation (MPC) is a promising technology for supporting privacy-preserving computation between multiple untrusted parties....     

Telephone communication with in-the-ear hearing aids using acoustic and electromagnetic coupling

The purpose of this study was to determine whether telephone communication was improved with electromagnetic coupling for in-the-ear hearing aid users with mild to moderate hearing losses. Each user adjusted his hearing aid gain to the level he determined to be best for telephone communication with each coupling method. Under these conditions, average word recognition scores in quiet and average high-frequency output levels measured at the tympanic membrane were not different for each coupling method. The ability to tolerate background noise was also studied. Background noise tolerance was not different for the two coupling methods. However, significantly greater levels of background noise were tolerated when telephone side-tone feedback was eliminated regardless of coupling method.