Imaging of Single Molecular Behaviors Under Bifurcated Three-Centered Hydrogen Bonding.

The mechanism for interaction and bonding of single guest molecules with active sites fundamentally determines the sorption and subsequent catalytic processes occurring in host zeolitic frameworks. However, no real-space studies on these significant issues have been reported thus far, since atomically visualizing guest molecules and recognizing single Al T-sites in zeolites remain challenging. Here, we atomically resolved single thiophene probes interacting with acid T-sites in the ZSM-5 framework to study the bonding behaviors between them.

Real-Space Imaging of the Molecular Changes in Metal-Organic Frameworks under Electron Irradiation.

Electron-induced structural changes influence the characterizations of the local structure of various materials by electron microscope. However, for beam-sensitive materials, it is still challenging to detect such changes by electron microscopy, which may help us quantitatively reveal how electrons interact with materials under electron irradiation. Here, we use an emergent phase contrast technique in electron microscopy to clearly image a metal-organic framework, UiO-66 (Zr), at an ultralow electron dose and dose rate.

Real-Space Imaging of the Node-Linker Coordination on the Interfaces between Self-Assembled Metal-Organic Frameworks.

Surface and interface, with unique local characteristics different from bulk structure, are of great significance in various applications of metal-organic frameworks (MOFs), which should be studied by real-space imaging methods, such as electron microscopy. However, it is still challenging to atomically resolve these local structures in MOFs, because they are even more sensitive to electron irradiation. Here, we use integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM) to achieve the atomic imaging of both the metal nodes and organic linkers in UiO-66 (Zr) nanocrystals and their assembly.

Atomic imaging of zeolite-confined single molecules by electron microscopy.

Single-molecule imaging with atomic resolution is a notable method to study various molecular behaviours and interactions. Although low-dose electron microscopy has been proved effective in observing small molecules, it has not yet helped us achieve an atomic understanding of the basic physics and chemistry of single molecules in porous materials, such as zeolites. The configurations of small molecules interacting with acid sites determine the wide applications of zeolites in catalysis, adsorption, gas separation and energy storage.

Modulating inherent lewis acidity at the intergrowth interface of mortise-tenon zeolite catalyst.

The acid sites of zeolite are important local structures to control the products in the chemical conversion. However, it remains a great challenge to precisely design the structures of acid sites, since there are still lack the controllable methods to generate and identify them with a high resolution. Here, we use the lattice mismatch of the intergrown zeolite to enrich the inherent Lewis acid sites (LASs) at the interface of a mortise-tenon ZSM-5 catalyst (ZSM-5-MT) with a 90° intergrowth structure.

In situ imaging of the sorption-induced subcell topological flexibility of a rigid zeolite framework.

The crystallographic pore sizes of zeolites are substantially smaller than those inferred from catalytic transformation and molecular sieving capabilities, which reflects flexible variation in zeolite opening pores. Using in situ electron microscopy, we imaged the straight channels of ZSM-5 zeolite with benzene as a probe molecule and observed subcell flexibility of the framework. The opening pores stretched along the longest direction of confined benzene molecules with a maximum aspect change of 15%, and the space group symmetry of the MFI framework caused adjacent channels to deform.

Intermittent theta burst stimulation (iTBS) combined with working memory training to improve cognitive function in schizophrenia: study protocol for a randomized controlled trial.

Background: Working memory deficit is one of the most critical complex cognitive impairments in schizophrenia. Repetitive transcranial magnetic stimulation (rTMS) is an effective adjuvant therapy, but not still unsatisfactory. Intermittent theta burst stimulation (iTBS), which has recently been used in clinical practice, may have faster and stronger effects comparing the traditional model (10-Hz high-frequency rTMS).

Enhanced production of aromatics from propane with a temperature-shifting two-stage fluidized bed reactor.

A temperature-shifting two-stage fluidized bed reactor technology was used to convert propane and its intermediate products into aromatics. The first stage served for the aromatization of propane with a Ga/ZSM-5 catalyst at 570 °C. The second stage served for the alkylation of the intermediates of olefins at 300 °C.

RNAi reduces expression and intracellular retention of mutant cartilage oligomeric matrix protein.

Mutations in cartilage oligomeric matrix protein (COMP), a large extracellular glycoprotein expressed in musculoskeletal tissues, cause two skeletal dysplasias, pseudoachondroplasia and multiple epiphyseal dysplasia. These mutations lead to massive intracellular retention of COMP, chondrocyte death and loss of growth plate chondrocytes that are necessary for linear growth. In contrast, COMP null mice have only minor growth plate abnormalities, normal growth and longevity.

An inducible cartilage oligomeric matrix protein mouse model recapitulates human pseudoachondroplasia phenotype.

Cartilage oligomeric matrix protein (COMP) is a pentameric extracellular protein expressed in cartilage and other musculoskeletal tissues. Mutations in the COMP gene cause pseudoachondroplasia (PSACH), a severe dwarfing condition that has a growth plate chondrocyte pathology. PSACH is characterized by intracellular retention of COMP and other extracellular matrix (ECM) proteins, which form an ordered matrix within large rough endoplasmic reticulum cisternae.