Isolation and Chemical Transformations Involving a Reactive Intermediate of MOF‑5

We report the isolation of a nonporous plate-like intermediate species (MOF-<i>i</i>) obtained during the synthesis of MOF-5 and the testing of this intermediate’s reactivity toward three metal ions (Zn^II, Cu^II, and Mn^II) in <i>N</i>,<i>N</i>-dimethylformamide at 120 °C. We obtained interpenetrated MOF-5 crystals from the reaction between MOF-<i>i</i> and Zn­(NO₃)₂·6H₂O, accompanied by a change in morphology from a plate to a cube. Reaction with CuCl₂·2H₂O did not disrupt the plate-like morphology of MOF-<i>i</i>, but it did result in the replacement of Zn^II by Cu^II and formation of a novel porous copper MOF. MOF-<i>i</i> showed no reactivity toward MnCl₂. Our results demonstrate that MOF-<i>i</i> imparts a selective reactivity that is different from the individual metal ions employed in conventional synthesis of MOFs and suggests that reactive intermediates may be useful in extending the diversity of metal–organic frameworks

<i>In Situ</i> Electron Microscopy Imaging and Quantitative Structural Modulation of Nanoparticle Superlattices

We use liquid-phase transmission electron microscopy (LP-TEM) to characterize the structure and dynamics of a solution-phase superlattice assembled from gold nanoprisms at the single particle level. The lamellar structure of the superlattice, determined by a balance of interprism interactions, is maintained and resolved under low-dose imaging conditions typically reserved for biomolecular imaging. In this dose range, we capture dynamic structural changes in the superlattice in real time, where contraction and smaller steady-state lattice constants are observed at higher electron dose rates. Quantitative analysis of the contraction mechanism based on a combination of direct LP-TEM imaging, ensemble small-angle X-ray scattering, and theoretical modeling allows us to elucidate: (1) the superlattice contraction in LP-TEM results from the screening of electrostatic repulsion due to as much as a 6-fold increase in the effective ionic strength in the solution upon electron beam illumination; and (2) the lattice constant serves as a means to understand the mechanism of the <i>in situ</i> interaction modulation and precisely calibrate electron dose rates with the effective ionic strength of the system. These results demonstrate that low-dose LP-TEM is a powerful tool for obtaining structural and kinetic properties of nanoassemblies in liquid conditions that closely resemble real experiments. We anticipate that this technique will be especially advantageous for those structures with heterogeneity or disorder that cannot be easily probed by ensemble methods and will provide important insight that will aid in the rational design of sophisticated reconfigurable nanomaterials

Structural, Electronic, and Magnetic Characterization of a Dinuclear Zinc Complex Containing TCNQ^– and a μ‑[TCNQ–TCNQ]^2– Ligand

A dinuclear zinc complex containing both a σ-dimerized 7,7,8,8-tetracyanoquinodimethane (TCNQ) ligand ([TCNQ–TCNQ]^2–) and TCNQ^– was synthesized for the first time. This is the first instance of a single molecular complex with a bridging [TCNQ–TCNQ]^2– ligand. Each zinc center is coordinated with two 2,2′-bipyrimidines and one TCNQ^–, and the remaining coordination site is occupied by a [TCNQ–TCNQ]^2– ligand, which bridges the two zinc centers. The complex facilitates π-stacking of TCNQ^– ligands when crystallized, which gives rise to a near-IR charge-transfer transition and strong antiferromagnetic coupling

Additional file 1: Table S1. of The impact of sitting time and physical activity on major depressive disorder in South Korean adults: a cross-sectional study

Men and women participants’ general characteristics. * Number of chronic diseases: Hypertension, dyslipidemia, stroke, myocardial infarction, angina, arthritis, rheumatoid arthritis, asthma, thyroid gland disorder, chronic renal failure, hepatitis B. * Number of chronic diseases: Hypertension, dyslipidemia, stroke, myocardial infarction, angina, arthritis, rheumatoid arthritis, asthma, thyroid gland disorder, chronic renal failure, hepatitis B. Table S2. Subgroup analysis of sitting-time and major depressive disorder according to physical activity. Adjusted for age, household income level, educational level, marital status, occupation, obesity, current smoking status, alcohol use and number of chronic diseases. (DOCX 51 kb

Polymerization-Like Co-Assembly of Silver Nanoplates and Patchy Spheres

Highly anisometric nanoparticles have distinctive mechanical, electrical, and thermal properties and are therefore appealing candidates for use as self-assembly building blocks. Here, we demonstrate that ultra-anisometric nanoplates, which have a nanoscale thickness but a micrometer-scale edge length, offer many material design capabilities. In particular, we show that these nanoplates “copolymerize” in a predictable way with patchy spheres (Janus and triblock particles) into one- and two-dimensional structures with tunable architectural properties. We find that, on the pathway to these structures, nanoplates assemble into chains following the kinetics of molecular step-growth polymerization. In the same mechanistic framework, patchy spheres control the size distribution and morphology of assembled structures, by behaving as monofunctional chain stoppers or multifunctional branch points during nanoplate polymerization. In addition, both the lattice constant and the stiffness of the nanoplate assemblies can be manipulated after assembly. We see highly anisometric nanoplates as one representative of a broader class of dual length-scale nanoparticles, with the potential to enrich the library of structures and properties available to the nanoparticle self-assembly toolbox

TRIM22 facilitates autophagosome-lysosome fusion by mediating the association of GABARAPs and PLEKHM1

Tripartite motif (TRIM) proteins are a large family of E3 ubiquitin ligases implicated in antiviral defense systems, tumorigenesis, and protein quality control. TRIM proteins contribute to protein quality control by regulating the ubiquitin-proteasome system, endoplasmic reticulum-associated degradation, and macroautophagy/autophagy. However, the detailed mechanisms through which various TRIM proteins regulate downstream events have not yet been fully elucidated. Herein, we identified a novel function of TRIM22 in the regulation of autophagy. TRIM22 promotes autophagosome-lysosome fusion by mediating the association of GABARAP family proteins with PLEKHM1, thereby inducing the autophagic clearance of protein aggregates, independent of its E3 ubiquitin ligase activity. Furthermore, a TRIM22 variant associated with early-onset familial Alzheimer disease interferes with autophagosome-lysosome fusion and autophagic clearance. These findings suggest TRIM22 as a critical autophagic regulator that orchestrates autophagosome-lysosome fusion by scaffolding autophagy-related proteins, thus representing a potential therapeutic target in neurodegenerative diseases.</p

Polymorphic Assembly from Beveled Gold Triangular Nanoprisms

The shape anisotropy of nanoparticle building blocks is of critical importance in determining their packing symmetry and assembly directionality. While there has been extensive research on the effect of their overall geometric shapes, the importance of nanometer morphology details is not well-recognized or understood. Here we draw on shape-anisotropic gold triangular nanoprism building blocks synthesized based on a method we recently developed; besides the “large-scale” triangular prism shape (79.8 nm in side length and 22.0 nm in thickness), the prisms are beveled with their sides convexly enclosed by two flat {100} facets. We engineer the balance between electrostatic repulsion and entropically driven depletion attraction in the system to generate self-assemblies without or with the effect of the nanoscale beveling detail. A conventional, planar honeycomb (p-honeycomb) lattice forms with the triangular basal planes packed on the same plane at low depletion attraction, whereas an unexpected interlocking honeycomb (i-honeycomb) lattice and its “supracrystal” forms are assembled with additional close-paralleling of side facets at high depletion attraction. The i-honeycomb lattice renders all the metallic surfaces in close proximity and leads to a surface-enhanced Raman scattering signal nearly 5-fold higher than that in the p-honeycomb lattice and high sensitivity for detecting the model molecule Rhodamine 6G at a concentration as low as 10^–8 M. Our study can guide future work in both nanoparticle synthesis and self-assembly; nanoscale geometrical features in anisotropic nanoparticles can be used as an important handle to control directional interactions for nonconventional ordered assemblies and to enrich diversity in self-assembly structure and function