Optoelectronic crystal of artificial atoms in strain-textured molybdenum disulphide

The isolation of the two-dimensional semiconductor molybdenum disulphide introduced a new optically active material possessing a band gap that can be facilely tuned via elastic strain. As an atomically thin membrane with exceptional strength, monolayer molybdenum disulphide subjected to biaxial strain can embed wide band gap variations overlapping the visible light spectrum, with calculations showing the modified electronic potential emanating from point-induced tensile strain perturbations mimics the Coulomb potential in a mesoscopic atom. Here we realize and confirm this ‘artificial atom’ concept via capillary-pressure-induced nanoindentation of monolayer molybdenum disulphide from a tailored nanopattern, and demonstrate that a synthetic superlattice of these building blocks forms an optoelectronic crystal capable of broadband light absorption and efficient funnelling of photogenerated excitons to points of maximum strain at the artificial-atom nuclei. Such two-dimensional semiconductors with spatially textured band gaps represent a new class of materials, which may find applications in next-generation optoelectronics or photovoltaics

Phenolic profile and free radical-scavenging activity of Cabernet Sauvignon wines of different geographical origins from the Balkan region

International audienceBACKGROUND: The phenolic profile, determined by the relative proportions of different phenolic compounds, is characteristic for each grape variety and its corresponding wine. The aim of this study was to determine the phenolic and hydroxycinnamate acid, flavan-3-ol and flavonol contents and free radical-scavenging activity of single-cultivar (Cabernet Sauvignon) wines from selected Balkan vineyard regions by spectrophotometric methods and high-performance liquid chromatography with photodiode array and fluorescence detection. RESULTS: The contents of phenolic compounds varied depending on the agroclimatic factors and oenological practices of the vineyard region. The antioxidant activity of wine samples was estimated by their ability to scavenge the stable 2,2'-diphenyl-1-picrylhydrazyl free radical (DPPH). All wines showed high DPPH-scavenging activity (70.03-83.53%, mean 73.76%). Significant correlations between catechin (R(2) = 0.8504) and quercetin (R(2) = 0.8488) concentrations and DPPH-scavenging ability of the wines were found. CONCLUSION: The concentrations of the main components catechin and quercetin can be used as biochemical markers for the authentication of red grape cultivars and their corresponding single-cultivar wines

State of Climate Action 2021: Systems Transformations Required to Limit Global Warming to 1.5°C

Limiting global warming to 1.5°C requires far-reaching transformations across power generation, buildings, industry, transport, land use, coastal zone management, and agriculture, as well as the immediate scale-up of technological carbon removal and climate finance. This report translates these transitions into 40 targets for 2030 and 2050, with measurable indicators.Transformations, particularly those driven by new technology adoption, often unfold slowly before accelerating after crossing a tipping point. Nearly a quarter of indicators assessed new technology adoption, with some already growing exponentially. This report considers such nonlinear change in its methodology.The transitions required to avoid the worst climate impacts are not happening fast enough. Of the 40 indicators assessed, none are on track to reach 2030 targets. Change is heading in the right direction at a promising but insufficient speed for 8 and in the right direction but well below the required pace for 17. Progress has stagnated for 3, while change for another 3 is heading in the wrong direction entirely. Data are insufficient to evaluate the remaining 9.This report also identifies underlying conditions that enable change—supportive policies, innovations, strong institutions, leadership, and shifts in social norms. Finance for climate action, for example, must increase nearly 13-fold to meet the estimated need in 2030