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Biomimetic and thermoresponsive hemostatic hydrogels based on gelatin (G), hyaluronic acid (HA), and poly-N-isopropylacrylamide (PNIPAM) have emerged as promising hemostats, but their performances are currently limited by the drawbacks of conventional grafting strategies, and the complicated operation and safety risk associated with photo-cross-linking or chemical cross-linking. It is highly appealing yet challenging to develop a facile strategy to prepare a physically cross-linked hemostatic hydrogel with rapid gelation and a robust network. Herein, an injectable, thermosensitive, and physically cross-linked double-network hemostatic hydrogel was prepared through simply blending G/HA with the linear PNIPAM (L-P) synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. The G/HA/L-P hydrogel could be conveniently injected via a syringe and cured in situ at body temperature. Its comprehensive performance could be tuned and optimized by adjusting the molecular weight of L-P and the proportions of components. Due to the non-covalent interactions including hydrogen bonding, hydrophobic interactions, and chain entanglements within the hydrogel network, the optimal performance of the G/HA/L-P hydrogel was achieved, i.e., gelation time 7–10 s, storage modulus 89 ± 3.5 kPa, adhesion strength 19.3 ± 2.5 kPa, and burst pressure 256 ± 27 mmHg. Meanwhile, the hydrogel exhibited significant coagulation effects in vitro and effective hemostatic properties in vivo. This work offers a simple and efficient strategy to fabricate high-performance smart hemostatic hydrogels. [ABSTRACT FROM AUTHOR]

Low ionic conductivity of solid electrolytes at intermediate temperatures hinders the commercialization process of solid fuel cell technology. A sodium superionic conductor (NASICON)-structure with a rigid three-dimensional network and an interconnected interstitial space is expected to be an ideal solid electrolyte for fuel cells. Based on the H+/Li+ exchange engineering strategy, here we report a NASICON-structure proton conductor Li1+xCdx/2Zr2−x/2(PO4)3 (x = 0.5, 1, 1.5, 2) derived from CdZr4(PO4)6 to construct a fuel cell device. Among all samples, the Li3Cd1Zr1(PO4)3 cell device exhibits a high performance including peak power density 815 mW cm−2, proton conductivity 0.165 S cm−1 and activation energy 0.372 eV at 550 °C. Theoretical and experimental studies both suggest that the high proton conductivity benefits from the unique 3D interstitial space and rapid H+/Li+ exchange in the NASICON material. Under fuel cell operating conditions, the interstitial space of Li1+xCdx/2Zr2−x/2(PO4)3 (x = 2) substitutes mobile Li+ with H+ enabling fast proton transport. The new transport mechanism and excellent proton conductivity suggest that Li1+xCdx/2Zr2−x/2(PO4)3 provides new opportunities for enriching novel electrolyte materials in intermediate temperature protonic ceramic fuel cells (IT-PCFCs). [ABSTRACT FROM AUTHOR]

High-spatial resolution fluorescence imaging on a high-density gold nanoelectrode array was achieved by anchoring fluorescent molecules to limit diffusion. Meanwhile, an ionic liquid as the electrolyte with a refractive index matching with the optical system could effectively improve the sensitivity of fluorescence imaging. Moreover, spatially resolved imaging of the electrochemical reactions on a single nanoelectrode modified with a single Pt nanoparticle was achieved. [ABSTRACT FROM AUTHOR]

An efficient rhodium-catalyzed asymmetric hydrogenation of α-amino acrylonitriles has been developed, affording α-acylamino nitriles with high yields and excellent enantioselectivities (up to 99% yield and ＞99% ee). This novel methodology provides an efficient and concise synthetic route to chiral α-amino nitriles, which are versatile intermediates in organic synthesis. [ABSTRACT FROM AUTHOR]

Chemical waves represent one of the fundamental behaviors that emerge in nonlinear, out-of-equilibrium chemical systems. They also play a central role in regulating behaviors and development of biological organisms. Nevertheless, understanding their properties and achieving their rational synthesis remains challenging. In this work, we obtained traveling chemical waves using synthetic organic molecules. To accomplish this, we ran a thiol-based reaction network in an unstirred flow reactor. Our observations revealed single or multiple waves moving in either the same or opposite directions, a behavior controlled by the geometry of our reactor. A numerical model can fully reproduce this behavior using the proposed reaction network. To better understand the formation of waves, we varied the diffusion coefficient of the fast inhibitor component of the reaction network by attaching polyethylene glycol tails with different lengths to maleimide and studied how these changes affect the properties of the waves and conditions for their sustained production. These studies point towards the importance of the molecular titration network motif in controlling the production of chemical waves in this system. Furthermore, we used machine learning (ML) tools to identify phase boundaries for classes of dynamic behaviors of this system, thus demonstrating the applicability of ML tools for the study of experimental nonlinear reaction-diffusion systems., Competing Interests: Authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Nickel-catalyzed asymmetric hydrogenation of challenging tetrasubstituted fluorinated enamides has been achieved, affording chiral α-fluoro-β-amino esters in high yields with excellent diastereo- and enantioselectivities (up to 98% yield, >99 : 1 dr, up to >99% ee). Deuterium-labeling experiments and control experiments were conducted to probe the mechanism, and the results indicated that the acidity of the solvent plays a critical role in the control of diastereoselectivity by trapping the adduct of nickel hydride to C[double bond, length as m-dash]C bonds via protonolysis, giving the hydrogenation product with stereospecific syn -selectivity. This protocol provides efficient access to chiral α-fluoro-β-amino esters which have important potential applications in organic synthesis and medicinal chemistry., (This journal is © The Royal Society of Chemistry 2019.)