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Radiation-induced defects in nanomaterials are an important aspect of the research on the effects of radiation on materials. Recently, the research on radiation-induced defects in semiconductor materials, low-dimensional materials, and high-specific-surface porous materials has become a new application of radiation technology. Radiation-induced nanomaterial defect engineering has the potential to be used to improve the electromagnetic, catalytic, adsorption, and mechanical properties of nanomaterials and will play an important role in materials science, electronic-device development, catalysis, and environmental science. Therefore, this review presents the recent progress and state-of-art in the formation and tuning mechanism of radiation-induced defects in nanomaterials and provides a direction for future development.

The structural, electronic, and magnetic properties of two-dimensional (2D) manganese dibromide (MnBr2) and manganese diiodide (MnI2) are investigated using first principles calculations. The dynamical and thermal stabilities of 2D MnBr2 and MnI2 have been illustrated from the phonon dispersion and molecular dynamic calculations. From the phonon dispersion, three Raman-active and three infrared-active vibration modes are found. The calculated formation energies and cleavage energies indicate that 2D MnBr2 and MnI2 are energetically stable and could be potentially obtained by exfoliation. The hybrid functional theory is employed to discover that 2D MnBr2 and MnI2 are wide gap semiconductors. The magnetic frustration is revealed by the calculation of magnetic exchange interaction and magnetocrystalline anisotropy interaction. By analyzing different magnetic orders, the relatively weak magnetic exchange is attributed to the competition of the direct exchange and the superexchange interaction. [ABSTRACT FROM AUTHOR]

Abstract: Hexagonal phase NaYF4:Yb3+ 20mol%/Er3+ 1mol% microcrystals that exhibit intense green emission were successfully synthesized via a facile hydrothermal method. The factors including the NaF/Ln (Ln=Y+Yb+Er) molar ratio, pH value of the precursor solution, and the ethylenediaminetetraacetic acid (EDTA)/Ln molar ratio, were well studied in the influences on the crystal structures, morphologies, and sizes of final products. The experimental results indicate that the NaF/Ln ratio and pH value play key roles in crystal structure and morphology of the product. Photoluminescence measurements demonstrate that the relative up-conversion photoluminescence intensity of as-prepared products strongly depends on the crystal structures, crystallization degrees, morphologies, and sizes. [Copyright &y& Elsevier]

Objectives: Helicobacter pylori ( H. pylori ) infection causes a variety of intragastric and extragastric diseases. Despite its decreasing global prevalence, it remains a major public health problem in many developing countries. This study aimed to understand the prevalence of H. pylori infection and its risk factors in five cities of the Ningxia Hui Autonomous Region, an area with high incidence of gastric cancer., Methods: Cross-sectional studies were conducted in Ningxia from 2017 and 2022, to detect the prevalence of H. pylori using the 14 C urea breath test. All participants completed a questionnaire that included demographics, personal habits, household economic characteristics, and previous health status. Multiple logistic regression analyses were used to identify independent factors for H. pylori infection., Results: Our findings demonstrated that the prevalence of H. pylori infection in Ningxia decreased significantly from 60.3% in 2017 to 43.6% in 2022, with an increase in public awareness rate from 35.9% in 2017 to 68.5% in 2022. The lowest infection rate was found in Zhongwei and highest in Guyuan. The prevalence of H. pylori infection was higher among Hui ethnicity, farmers, individuals living in rural areas, individuals with lower income, low education, and those who consumed less fruit. Gallbladder, respiratory, cardiovascular and autoimmune diseases were not associated with H. pylori infection., Conclusions: The prevalence of H. pylori in Ningxia decreased in the past five years. Ethnicity, location, occupation, income, education, and consumption of fruits were independent risk factors for H. pylori infection in Ningxia. It was not associated with extra-gastric disease., Competing Interests: None., (AJTR Copyright © 2022.)