Martina Costa Reis · 2025 · ACS Omega · ACS Publications · added 2026-04-20
Chemical gardens are hollow precipitates with a plant-like appearance formed when a metal salt seed is immersed in an alkaline aqueous solution containing silicate, phosphate, or carbonate ions. Due t Show more
Chemical gardens are hollow precipitates with a plant-like appearance formed when a metal salt seed is immersed in an alkaline aqueous solution containing silicate, phosphate, or carbonate ions. Due to their potential to mimic biological and geological structures relevant to the understanding of life's emergence on Earth and Mars, the study of the nonequilibrium properties of chemical gardens has become increasingly important. Hence, in this article, the influence of gravity on the formation and growth of chemical gardens is investigated. To this end, experimental evidence of the influence of gravity on the formation and growth of chemical gardens is analyzed according to nonequilibrium sensitivity theory. The results obtained from the nonequilibrium sensitivity analysis show that the upward-growing pattern observed in chemical gardens, usually formed under Earth's gravity, is a consequence of symmetry breaking in the system's bifurcating solutions. Under these circumstances, the thermal fluctuations within the system become negligible, favoring the vertical growth of the chemical garden. Moreover, by exploiting the definition of nonequilibrium sensitivity, the minimum magnitude of the gravitational field necessary for the vertical growth of a chemical garden was estimated. The results indicate that the upward growth pattern emerges as the dominant dissipative structure for gravitational field magnitudes larger than 10-5 m s-2, provided fluctuations remain negligible. Show less
Gregori-Puigjané E, Setola V, Hert J+6 more · 2012 · Proceedings of the National Academy of Sciences of the United States of America · National Academy of Sciences · added 2026-04-20
Notwithstanding their key roles in therapy and as biological probes, 7% of approved drugs are purported to have no known primary target, and up to 18% lack a well-defined mechanism of action. Using a Show more
Notwithstanding their key roles in therapy and as biological probes, 7% of approved drugs are purported to have no known primary target, and up to 18% lack a well-defined mechanism of action. Using a chemoinformatics approach, we sought to "de-orphanize" drugs that lack primary targets. Surprisingly, targets could be easily predicted for many: Whereas these targets were not known to us nor to the common databases, most could be confirmed by literature search, leaving only 13 Food and Drug Administration-approved drugs with unknown targets; the number of drugs without molecular targets likely is far fewer than reported. The number of worldwide drugs without reasonable molecular targets similarly dropped, from 352 (25%) to 44 (4%). Nevertheless, there remained at least seven drugs for which reasonable mechanism-of-action targets were unknown but could be predicted, including the antitussives clemastine, cloperastine, and nepinalone; the antiemetic benzquinamide; the muscle relaxant cyclobenzaprine; the analgesic nefopam; and the immunomodulator lobenzarit. For each, predicted targets were confirmed experimentally, with affinities within their physiological concentration ranges. Turning this question on its head, we next asked which drugs were specific enough to act as chemical probes. Over 100 drugs met the standard criteria for probes, and 40 did so by more stringent criteria. A chemical information approach to drug-target association can guide therapeutic development and reveal applications to probe biology, a focus of much current interest. Show less