Crystallization of calcium carbonate, typically, progresses sequentially via metastable phases. Amorphous CaCO 3 (ACC) generally forms initially, both in vitro and in vivo, and is the precursor of the predominant anhydrous polymorphs (calcite, aragonite, and vaterite). [1][2][3][4][5][6][7][8][9][10][11][12][13] A new picture of the crystallization of calcium carbonate is emerging, which involves transformations of clusters to ACC and eventually to crystalline polymorphs. [14,15] This stepwise manner has implications for the understanding of biomineralization [16] and of crystallization. ACCs that contain additives display order over atomic length scales that are related to crystalline polymorphs; [1][2][3] ACC synthesized at high supersaturation levels without additives, [17][18][19][20] on the other hand, show no distinct short-range order. [21,22] Herein, we analyze proto-crystalline features of two amorphous intermediates, ACCI and ACCII, [15] and discuss their relevance for crystallization of CaCO 3 . We rationalize the identification of ACCI with pc-ACC (proto-calcite ACC) and ACCII with pv-ACC (proto-vaterite ACC), respectively. These ACCs were precipitated from metastable solutions of calcium carbonate at different pH values by destabilization in excess ethanol.TEM (Figure 1) reveals the ACCs as spherical particles with a diameter of approximately 20 nm. Small-angle X-ray scattering (SAXS) data support this characteristic size

Background: Mutations in GJB2 are the most common molecular defects responsible for autosomal recessive nonsyndromic hearing impairment (NSHI). The mutation spectra of this gene vary among different ethnic groups.

Crystallization of calcium carbonate, typically, progresses sequentially via metastable phases. Amorphous CaCO 3 (ACC) generally forms initially, both in vitro and in vivo, and is the precursor of the predominant anhydrous polymorphs (calcite, aragonite, and vaterite). [1][2][3][4][5][6][7][8][9][10][11][12][13] A new picture of the crystallization of calcium carbonate is emerging, which involves transformations of clusters to ACC and eventually to crystalline polymorphs. [14,15] This stepwise manner has implications for the understanding of biomineralization [16] and of crystallization. ACCs that contain additives display order over atomic length scales that are related to crystalline polymorphs; [1][2][3] ACC synthesized at high supersaturation levels without additives, [17][18][19][20] on the other hand, show no distinct short-range order. [21,22] Herein, we analyze proto-crystalline features of two amorphous intermediates, ACCI and ACCII, [15] and discuss their relevance for crystallization of CaCO 3 . We rationalize the identification of ACCI with pc-ACC (proto-calcite ACC) and ACCII with pv-ACC (proto-vaterite ACC), respectively. These ACCs were precipitated from metastable solutions of calcium carbonate at different pH values by destabilization in excess ethanol. TEM (Figure 1) reveals the ACCs as spherical particles with a diameter of approximately 20 nm. Small-angle X-ray scattering (SAXS) data support this characteristic size Figure 1. TEM images of pc-ACC and pv-ACC at various magnifications. Insets in (b) and (e) are selective area electron diffraction (SAED) patterns obtained from an area slightly larger than the particular image sections, SAED scale bars: 5 nm À1 . SAED patterns are shown as negatives to make weak features clear. Arrows in (f) indicate nanostructural features.

A novel, highly selective photocyclic aromatization (SCAT) of π-conjugated polymers from phenylacetylene having two hydroxyl groups to exclusively yield a 1,3,5-trisubstituted benzene derivative was developed, and its success was confirmed by (1)H NMR, GPC, and TOF-MS. The SCAT reaction has many unique characteristics. (1) It is a quantitative reaction: it gave only the corresponding cyclic trimer, i.e., a 1,3,5-trisubstituted benzene derivative, quantitatively (100%). No byproducts were produced under the best conditions. (2) It is an intramolecular reaction: it occurred between three adjacent monomer units in one macromolecule. (3) It is a stereospecific and topochemical or template reaction: the reactivity strongly depended on the configuration and conformation of the starting polymer substrates. (4) It is a photoreaction: high selectivity (100%) was observed only by the use of visible light irradiation, not by heating. (5) It is a solid-state reaction: high selectivity (100%) was observed only in the solid state, not in solution. In addition, (6) the resulting cyclic trimers could form a self-supporting membrane, despite their low molecular weights. This new approach resulted in a new class of supramolecular polymers consisting of a 1,3,5-trisubstituted benzene derivative, numbers of which were linearly linked by hydrogen bonds and stacked benzene derivatives. Since SCAT has such high selectivities and is useful for the preparation of a self-supporting supramolecular polymer membrane, many applications can be expected.

To achieve zero-carbon economy, advanced anode catalysts are desirable for hydrogen production and biomass upgrading powered by renewable energy. Ni-based non-precious electrocatalysts are considered as potential candidates because of intrinsic redox attributes, but in-depth understanding and rational design of Ni site coordination still remain challenging. Here, we perform anodic electrochemical oxidation of Ni-metalloids (NiPx, NiSx, and NiSex) to in-situ construct different oxyanion-coordinated amorphous nickel oxyhydroxides (NiOOH-TOx), among which NiOOH-POx shows optimal local coordination environment and boosts electrocatalytic activity of Ni sites towards selective oxidation of methanol to formate. Experiments and theoretical results demonstrate that NiOOH-POx possesses improved adsorption of OH* and methanol, and favors the formation of CH3O* intermediates. The coordinated phosphate oxyanions effectively tailor the d band center of Ni sites and increases Ni-O covalency, promoting the catalytic activity. This study provides additional insights into modulation of active-center coordination environment via oxyanions for organic molecules transformation.