Polymeric Hydronitrogen N₄H: A Promising High-Energy-Density Material and High-Temperature Superconductor

Solid nitrogen-rich compounds are potential high-energy-density materials (HEDMs). The enormous challenge in this area is to synthesize and stabilize these energetic materials at moderate pressure and better under near-ambient conditions. Here, we perform an extensive theoretical study on hydronitrogens by the reverse design method considering both energies and energy densities. Four hydronitrogens with different stoichiometries, that is, N4H, N3H, N2H, and NH, are found to be stable at pressures of about 80–300 GPa and metastable with pressure releasing to ambient pressure. The energy densities of these hydronitrogens are about 5.6–6.5 kJ/g and 1.3–1.5 times larger than that of trinitrotoluene (TNT). Most importantly, the Pbam phase of the N4H compound is an excellent high-temperature superconductor with a Tc of 37.7 K at 72 GPa. The present findings enrich new phases of hydronitrogens under high pressure and characterize their structural and energetic properties and superconductivity, which offer crucial insights for further design and synthesis of exceptional materials with high energy density and high-temperature superconductivity

Partial Surface Oxidation of Manganese Oxides as an Effective Treatment To Improve Their Activity in Electrochemical Oxygen Reduction Reaction

Enhancing the electrocatalytic activity of low-cost transition-metal oxides for oxygen reduction reaction (ORR) is a crucial challenge for extensive application of fuel cells. A promising approach demonstrated previously is the formation of catalysts with mixed valent metal active sites. Because catalysis happens primarily on the surface of the catalyst, we hypothesize that creating such active sites only on the surface will be an effective strategy for improving the catalytic activities. Here, we present a partial oxidation approach that grows δ-MnO2 nanoflakes on the surface of octahedron Mn3O4 nanocrystals for increasing their ORR activity. The δ-MnO2/Mn3O4 nanocomposite exhibits significantly improved ORR activity with a half-wave potential of 0.75 V versus reversible hydrogen electrode, which is ∼110 and ∼90 mV lower than those of the Mn3O4 nanocrystal and δ-MnO2 nanoflakes in their pure forms, respectively. The electrochemical impedance spectroscopy reveals that the δ-MnO2/Mn3O4 nanocomposite possesses a lower ORR charge transfer resistance than either component alone. We propose that the reason for such significant improvement in catalytic activities is due to the tuning of the position of δ-MnO2 nanoflake d-band center by the Mn3O4 nanocrystal which can effectively facilitate the electron transfer between the active sites and adsorbed oxygen molecules. This work illustrates a facile pathway to improve catalytic activity of mixed valence metal oxides

sj-docx-1-ear-10.1177_01455613231181456 – Supplemental material for Diagnosis and Therapeutic Strategies of Unusual Subglottic Pleomorphic Adenoma: A Rare Case Report and Literature Review

Supplemental material, sj-docx-1-ear-10.1177_01455613231181456 for Diagnosis and Therapeutic Strategies of Unusual Subglottic Pleomorphic Adenoma: A Rare Case Report and Literature Review by Xiaoru Sun, Dan He, Qiao Wen, Shi He, Yong Jiang, Shixi Liu, Haiyang Wang and Jian Zou in Ear, Nose & Throat Journal</p

Table_1_COVID-19 impacts on cross-border mobility of senior population between Shenzhen and Hong Kong.DOCX

The onset of the COVID-19 outbreak led to widespread adoption of mobility intervention policies, which were widely regarded as effective measures to control the spread of the virus. The initial pandemic wave, accompanied by the enforcement of mobility intervention policies, greatly changed human mobility patterns, especially cross-border mobility (CBM). This study investigates the impact of the first wave of the pandemic and related mobility intervention policies on the CBM of the senior population between Shenzhen and Hong Kong. Based on anonymous mobile phone trajectory data from 17 million devices active in Shenzhen spanning December 2019 to May 2020, we consider the implementation of mobility intervention policies during different stages of pandemic in both cities. We adopt interrupted time series (ITS) analysis to explore the causal effects of different mobility intervention policies on the CBM of older people between Hong Kong and Shenzhen. We find that most mobility intervention policies have a significant abrupt or gradual effect on the CBM of older people, especially in the 60–64 age group. As these policies neglect the mobility needs and characteristics among the senior groups, such as visiting relatives or friends and seeking medical treatment across borders, we suggest that more coordinated and integrated policies and measures are required to address the CBM needs of older people in Shenzhen and Hong Kong, especially in the post-pandemic era.</p

Tumor-Microenvironment-Activatable Nanoparticle Mediating Immunogene Therapy and M2 Macrophage-Targeted Inhibitor for Synergistic Cancer Immunotherapy

Immunotherapy has achieved prominent clinical efficacy in combating cancer and has recently become a mainstream treatment strategy. However, achieving broad efficacy with a single modality is challenging, and the heterogeneity of the tumor microenvironment (TME) restricts the accuracy and effectiveness of immunotherapy strategies for tumors. Herein, a TME-responsive targeted nanoparticle to enhance antitumor immunity and reverse immune escape by codelivering interleukin-12 (IL-12) expressing gene and colony-stimulating factor-1 receptor (CSF-1R) inhibitor PLX3397 (PLX) is presented. The introduction of disulfide bonds and cyclo(Arg-Gly-Asp-d-Phe-Lys) (cRGD) peptides conferred reduction reactivity and tumor targeting to the nanoparticles, respectively. It is hypothesized that activating host immunity by the local expression of IL-12, while modulating the tumor-associated macrophages (TAM) function through blocking CSF-1/CSF-1R signaling, could constitute a feasible approach for cancer immunotherapy. The fabricated functional nanoparticle successfully ameliorated the TME by stimulating the proliferation and activation of T lymphocytes, promoting the repolarization of TAMs, reducing myeloid-derived suppressor cells (MDSCs), and promoting the maturation of dendritic cells (DC) as well as the secretion of antitumor cytokines, which efficiently suppressed tumor growth and metastasis. Finally, substantial changes in the TME were deciphered by single-cell analysis including infiltration of different cells, transcriptional states, secretory signaling and cell–cell communications. These findings provide a promising combinatorial immunotherapy strategy through immunomodulatory nanoparticles

Probing Nucleation Pathways for Morphological Manipulation of Platinum Nanocrystals

Understanding the formation process in the controlled synthesis of nanocrystals will lead to the effective manipulation of the morphologies and properties of nanomaterials. Here, <i>in-situ</i> UV–vis and X-ray absorption spectroscopies are combined to monitor the tracks of the nucleation pathways in the solution synthesis of platinum nanocrystals. We find experimentally that the control over nucleation pathways through changing the strength of reductants can be efficiently used to manipulate the resultant nanocrystal shapes. The <i>in-situ</i> measurements show that two different nucleation events involving the formation of one-dimensional “Pt_<i>n</i>Cl_<i>x</i>” complexes from the polymerization of linear “Cl₃Pt–PtCl₃” dimers and spherical “Pt_<i>n</i>⁰” clusters from the aggregation of Pt⁰ atoms occur for the cases of weak and strong reductants; and the resultant morphologies are nanowires and nanospheres, respectively. This study provides a crucial insight into the correlation between the particle shapes and nucleation pathways of nanomaterials