A series of chalcones was evaluated as antimitotic agents. One of these, (E)-1-(2,5-dimethoxyphenyl)-3-[4-(dimethylamino)phenyl]-2-methyl-2-pr open- 1-one) (73), was found to be an effective antimitotic agent at a concentration of 4 nM in an in vitro HeLa cell test system. When evaluated in experimental tumor models in vivo, this compound exhibited antitumor activity against L1210 leukemia and B16 melanoma.

A rapid transition away from unabated coal use is essential to fulfilling the Paris climate goals. However, many countries are actively building and operating coal power plants. Here we use plant-level data to specify alternative trajectories for coal technologies in an integrated assessment model. We then quantify cost-effective retirement pathways for global and country-level coal fleets to limit long-term temperature change. We present our results using a decision-relevant metric: the operational lifetime limit. Even if no new plants are built, the lifetimes of existing units are reduced to approximately 35 years in a well-below 2 °C scenario or 20 years in a 1.5 °C scenario. The risk of continued coal expansion, including the near-term growth permitted in some Nationally Determined Contributions (NDCs), is large. The lifetime limits for both 2 °C and 1.5 °C are reduced by 5 years if plants under construction come online and 10 years if all proposed projects are built.

Energy technologies emit greenhouse gases with differing radiative efficiencies and atmospheric lifetimes [1][2][3]. Standard practice for evaluating technologies, which uses the global warming potential (GWP) to compare the integrated radiative forcing of emitted gases over a fixed time horizon [4], does not acknowledge the importance of a changing background climate relative to climate change mitigation targets [5,6]. Here we demonstrate that the GWP misvalues the impact of CH 4 -emitting technologies as mid-century approaches, and we propose a new class of metrics to evaluate technologies based on their time of use. The instantaneous climate impact (ICI) compares gases in an expected radiative forcing stabilization year, and the cumulative climate impact (CCI) compares their integrated radiative forcing up to a stabilization year. Using these dynamic metrics, we quantify the climate impacts of technologies and show that high-CH 4 -emitting energy sources become less advantageous over time. The impact of natural gas for transportation, with CH 4 leakage, exceeds that of gasoline within 1-2 decades for a commonly-cited 3 W/m 2 stabilization target. The impact of algae biodiesel overtakes that of corn ethanol within 2-3 decades, where algae co-products are used to produce biogas and corn co-products are used for animal feed. The proposed metrics capture the changing importance of CH 4 emissions as a climate threshold is approached, thereby addressing a major shortcoming of the GWP for technology evaluation [7,8].Comparing the climate impacts of energy technologies is challenging because they emit differing types and quantities of greenhouse gases, most notably CH 4 and CO 2 , and these gases have dissimilar properties (Fig. 1a,b). Present approaches to technology evaluation use an equivalency metric to convert emissions to their CO 2 -equivalent value [1][2][3]9]. The most common metric is the global warming potential (GWP(τ )), which takes the ratio of the time-integrated radiative forcing of pulse non-CO 2 and CO 2 emissions over a fixed time horizon (τ ), typically 100 years. The GWP(100) was initially intended as a placeholder [10], in large part because of its sensitivity to the arbitrarily selected time horizon [7] (Fig. 1c,d), but it remains the standard metric for technology evaluation.

More than half of current coal power capacity is in China. A key strategy for meeting China’s 2060 carbon neutrality goal and the global 1.5 °C climate goal is to rapidly shift away from unabated coal use. Here we detail how to structure a high-ambition coal phaseout in China while balancing multiple national needs. We evaluate the 1037 currently operating coal plants based on comprehensive technical, economic and environmental criteria and develop a metric for prioritizing plants for early retirement. We find that 18% of plants consistently score poorly across all three criteria and are thus low-hanging fruits for rapid retirement. We develop plant-by-plant phaseout strategies for each province by combining our retirement algorithm with an integrated assessment model. With rapid retirement of the low-hanging fruits, other existing plants can operate with a 20- or 30-year minimum lifetime and gradually reduced utilization to achieve the 1.5 °C or well-below 2 °C climate goals, respectively, with complete phaseout by 2045 and 2055.