Search

Immune cells are indispensable defenders of the human body, clearing exogenous pathogens and toxicities or endogenous malignant and aging cells. Immune cell dysfunction can cause an inability to recognize, react, and remove these hazards, resulting in cancers, inflammatory diseases, autoimmune diseases, and infections. Immune cells regulation has shown great promise in treating disease, and immune agonists are usually used to treat cancers and infections caused by immune suppression. In contrast, immunosuppressants are used to treat inflammatory and autoimmune diseases. However, the key to maintaining health is to restore balance to the immune system, as excessive activation or inhibition of immune cells is a common complication of immunotherapy. Nanoparticles are efficient drug delivery systems widely used to deliver small molecule inhibitors, nucleic acid, and proteins. Using nanoparticles for the targeted delivery of drugs to immune cells provides opportunities to regulate immune cell function. In this review, we summarize the current progress of nanoparticle-based strategies for regulating immune function and discuss the prospects of future nanoparticle design to improve immunotherapy.

Objective To summarize the clinical, imaging and genetic characteristics of spinocerebellar ataxia 2 (SCA2) families presenting as Parkinsonism. Methods and Results Two families with autosomal dominant SCA2 with Parkinson's syndrome diagnosed by genetic test in Peking University First Hospital from May 2019 to December 2020 were included. The probands in 2 families manifested as lead⁃pipe like rigidity and cerebellum ataxia. Electronystagmography (ENG) in proband of family 1 showed gaze nystagmus, understable saccade, decreased smooth tracking ability and disappeared optokinetic nystagmus, proband of family 2 showed slow saccade, decreased smooth tracking ability and decreased optokinetic nystagmus. Head MRI in both probands of 2 families showed slightly enlarged third ventricle, while the proband of family 2 showed atrophy in brain stem and cerebellar. Whole exome sequencing (WES) in 2 probands showed no gene mutations, Sanger sequencing showed dynamic mutation of ATXN2 gene and the copy number of cytosine⁃adenine⁃guanine (CAG) with 37 repeats. Two probands were finally diagnosed as SCA2, and two pedigrees were diagnosed as SCA2 pedigrees. Conclusions SCA2 can present as Parkinsonism, which is easily to be misdiagnosed as Parkinson's disease due to the effective treatment of levodopa. ENG is helpful in detecting subclinical cerebellar lesions. For Parkinsonism patients with family history, especially when cerebellar lesions are involved, ATXN2 gene testing is recommended.

In situ exploration of the dynamic structure evolution of catalysts plays a key role in revealing reaction mechanisms and designing efficient catalysts. In this work, PtCu/MgO catalysts, synthesized via the co-impregnation method, outperforms monometallic Pt/MgO and Cu/MgO. Utilizing quasi/in-situ characterization techniques, it is discovered that there is an obvious structural evolution over PtCu/MgO from PtxCuyOz oxide cluster to PtCu alloy with surface CuOx species under different redox and CO oxidation reaction conditions. The synergistic effect between PtCu alloy and CuOx species enables good CO oxidation activity through the regulation of CO adsorption and O2 dissociation. At low temperatures, CO oxidation is predominantly catalyzed by surface CuOx species via the Mars-van Krevelen mechanism, in which CuOx can provide abundant active oxygen species. As the reaction temperature increases, both surface CuOx species and PtCu alloy collaborate to activate gaseous oxygen, facilitating CO oxidation mainly through the Langmuir-Hinshelwood mechanism. This study reveals the structural evolution of PtCu/MgO catalysts from a PtCu alloy to a PtCu alloy with CuOx under redox conditions which is found to exhibit distinct effects between CuOx and PtCu alloy at different temperatures during CO oxidation. [ABSTRACT FROM AUTHOR]

BackgroundEthylene is an important raw material in petrochemical industry. Semi-hydrogenation of acetylene in an ethylene is an industrially important process. Conventional supported monometallic Pd catalysts offer high acetylene conversion, but they suffer from very low selectivity to ethylene due to over-hydrogenation.PurposeThis study aims to prepare a catalyst with high acetylene conversion and simultaneous selectivity to ethylene, surpassing conventional Pd catalysts, and explore the structure activity relationship of palladium-bismuth catalyst in acetylene hydrogenation.MethodsFirstly, PdBi/SiO2 catalyst was synthesized via a deposition-precipitation method for industrial hydrogenation of acetylene to ethylene. Then, comparison of catalytic activity and selectivity with traditional catalysts in the semi hydrogenation reaction of acetylene was conducted. Finally, the X-ray Absorption Fine Structure (XAFS), High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy (HAADF-STEM), and X-ray Energy Dispersive Spectroscopy (EDS) were employed to explore the reaction mechanism.ResultsCompared with the Pd catalyst, PdBi/SiO2 catalyst exhibits increased reactivity at a lower temperature, with 100% acetylene conversion and 90% selectivity.ConclusionsThe Pd-Bi alloys structure is confirmed to effectively inhibit the formation of PdHx, weaken the cracking rate of hydrogen and the adsorption of ethylene on palladium surface, and inhibit the excessive hydrogenation of ethylene to produce by-product ethane. The simple synthesis PdBi structure provides new ideas and insights for industrial catalysts.