Global potential for harvesting drinking water from air using solar energy

Access to safely managed drinking water (SMDW) remains a global challenge, and affects 2.2 billion people^1,2. Solar-driven atmospheric water harvesting (AWH) devices with continuous cycling may accelerate progress by enabling decentralized extraction of water from air^3-6, but low specific yields (SY) and low daytime relative humidity (RH) have raised questions about their performance (in litres of water output per day)^7-11. However, to our knowledge, no analysis has mapped the global potential of AWH¹² despite favourable conditions in tropical regions, where two-thirds of people without SMDW live². Here we show that AWH could provide SMDW for a billion people. Our assessment-using Google Earth Engine¹³-introduces a hypothetical 1-metre-square device with a SY profile of 0.2 to 2.5 litres per kilowatt-hour (0.1 to 1.25 litres per kilowatt-hour for a 2-metre-square device) at 30% to 90% RH, respectively. Such a device could meet a target average daily drinking water requirement of 5 litres per day per person¹⁴. We plot the impact potential of existing devices and new sorbent classes, which suggests that these targets could be met with continued technological development, and well within thermodynamic limits. Indeed, these performance targets have been achieved experimentally in demonstrations of sorbent materials^15-17. Our tools can inform design trade-offs for atmospheric water harvesting devices that maximize global impact, alongside ongoing efforts to meet Sustainable Development Goals (SDGs) with existing technologies.

[Intra-arterial thrombolytic therapy of lower limb ischemia]

Between 1984 and 1989, 35 patients with recent arterial or graft occlusions have been treated with intra-arterial infusion using sequential association of Urokinase (U.K.) and Lys-Plasminogen. Occlusion was thrombotic in 68.5% of the cases ans embolic in 31.5%, involving 28 native arteries and 7 bypass grafts. The mean duration was 16 days (2 to 90). Continuous infusion of U.K.: 84,000 U.I./H and bolus of Lys-Plasminogen 15 microKatals every 30 minutes were delivered through a catheter embedded into the clot. Intra-venous heparin was always associated. The mean duration of lytic drug infusion was 8 H. Complementary arterial reconstruction by vascular surgery of percutaneous transluminal angioplasty was performed in 23% of the patients. Patients with recent alimentary tract bleeding, hemorragic stroke in the last six months or severe high blood pressures were contra-indicated. Complete lysis was obtained in 23 cases (66%), partial lysis in 7 (20%) and no lysis in 5 (14%). The clinical result was excellent in 24 cases (68.5%), good in 3 (8.5%) and bad in 8 (23%) in which amputation was always necessary. 5 local hematoma (14%) treated by surgery or transfusion and one death (3%) due to neurological complication occurring 24 hours after the end of the procedure were observed. The literature survey has shown that the results of low doses of Streptokinase (S.K.) local infusions were not better, and that higher doses of S.K. or U.K. delivered during a shorter infusion time increased the efficacy of lysis and decreased the rate of hemorragic complications. We have proposed the local thrombolytic treatment to the limb threatening ischemic cases when the traditional medical or surgical techniques where thought to be associated to a high risk of failure or complication. The specific indications are the acute or sub-acute ischemic situation due to atheromatous artery thrombosis, distal or old embolism where the Fogarty catheter is inefficient, and graft thrombosis. Severe acute ischemia with neurologic involvement are not good indications. Local thrombolysis can be successful on arterial occlusion even after one month duration.