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Monovalent salts are generally believed to stabilize DNA duplex by weakening inter-strand electrostatic repulsion. Unexpectedly, our force-induced hairpin unzipping experiments and thermal melting experiments show that LiCl, NaCl, KCl, RbCl, and CsCl at concentrations beyond ~1 M destabilize DNA, RNA, and RNA-DNA duplexes. The two types of experiments yield different changes in free energy during melting, while the results that high concentration monovalent salts destabilize duplexes are common. The effects of these monovalent ions are similar but also have noticeable differences. From 1 M to 4 M, DNA duplex is destabilized by about 0.3 kBT/bp and the melting temperature decreases by about 10 oC. Our all-atom simulations reveal this effect is caused by overcharging, where excessive ion absorption inverts the effective DNA charge from negative to positive. Furthermore, our coarse-grained simulations obtain a phase diagram that indicates whether DNA overcharging occurs at a given cation valence and concentration. These findings challenge the traditional belief that DNA overcharging occurs only with multivalent ions and have significant implications for polyelectrolyte theory, DNA nanomaterials, DNA nanotechnology, and DNA biophysics. Experiments and simulations suggest monovalent salts destabilize DNA/RNA because of overcharging. These findings challenge views that overcharging requires multivalent ions, with implications for nanomaterials, nanotechnology, and biophysics. [ABSTRACT FROM AUTHOR]

Balancing land development and ecological protection poses significant challenges for sustainable development in arid and semi‐arid regions like Inner Mongolia. This study uses the integrated valuation of ecosystem services (ESs) trade‐offs model and patch‐generated land‐use simulation model to analyze the impacts of land‐use/cover (LULC) changes on ESs from 2005 to 2020 and simulate scenarios for 2035. The results show that (1) ecological governance efforts improved the comprehensive ecological index (CEI), habitat quality, and soil conservation capacity but led to a decrease in the annual water yield (AWY) in the eastern region. Additionally, the conversion of grassland and forest land to construction land and farmland caused slight declines in carbon sequestration and increased nitrogen export. (2) The external driving factors of different ESs vary, and the internal relationships within ESs have also changed. Notably, changes in LULC transformed the synergy between AWY and habitat quality into a trade‐off relationship after 2010 due to increased forest and grassland. (3) Among the five land‐use scenarios, the comprehensive development scenario combined with zonal management strategies can achieve the sustainable development goals of economic growth, ecological protection, and food security. This study clarifies the internal and external factors affecting ESs in Inner Mongolia and provides a scientific basis for future LULC management and ecological governance policies. It fills a gap in the spatiotemporal simulation of ESs under multiple scenarios in this region. These findings offer valuable references for promoting sustainable development in similar arid and semi‐arid regions, highlighting the importance of integrating multi‐objective strategies and adaptive management practices to balance ecological and economic objectives. [ABSTRACT FROM AUTHOR]

We report a convenient method for benzylic H/D exchange of a wide variety of substrates bearing primary, secondary, or tertiary C−H bonds via a reversible η6‐coordination strategy. A doubly cationic [CpCF3RhIII]2+ catalyst that serves as an arenophile facilitates deprotonation of inert benzylic hydrogen atoms (pKa>40 in DMSO) without affecting other hydrogen atoms, such as those on aromatic rings or in α‐positions of carboxylate groups. Notably, the H/D exchange reactions feature high stereoretention. We demonstrated the potential utility of this method by using it for deuterium labeling of ten pharmaceuticals and their analogues. [ABSTRACT FROM AUTHOR]