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Two-dimensional (2D) materials have stimulated continued interest due to their potential applications in fields from electronic, optical to catalysis and energy. Compared with the widely studied 2D metal chalcogenides, 2D oxides could be of particular interest for a ranges of applications where oxidative and high temperature conditions are involved. This feature of 2D oxides, combined with the inherent benefits of 2D systems could also be important for nonlinear optical (NLO) studies that involves strong light-matter interactions. Here we focus on the recent advances in the exploration of 2D metal oxides for nonlinear optics and ultrafast photonic applications. Along with a brief description of the crystal structures, fabrication methods and general properties of 2D oxides, we concentrate our discussion on the recent progresses in the nonlinear optical studies on 2D systems of both metallic and nonmetallic nature. The strong NLO absorption of these 2D oxides has been utilized for the development of optical switches for driving pulse generation in a number of fiber and solid-state lasers operating in the near infrared range. This review finally presents a brief analysis of main challenges of 2D metal oxides in the field nonlinear photonics and a short discussion on potential future directions. [ABSTRACT FROM AUTHOR]

Astatine (211At) is a cyclotron-produced alpha emitter with a physical half-life of 7.2 h. In our previous study, the 211At-labeled prostate-specific membrane antigen (PSMA) compound ([211At]PSMA-5) exhibited excellent tumor growth suppression in a xenograft model. We conducted preclinical biodistribution and toxicity studies for the first-in-human clinical trial. [211At]PSMA-5 was administered to both normal male ICR mice (n = 85) and cynomolgus monkeys (n = 2). The mice were divided into four groups for the toxicity study: 5 MBq/kg, 12 MBq/kg, 35 MBq/kg, and vehicle control, with follow-ups at 1 day (n = 10 per group) and 14 days (n = 5 per group). Monkeys were observed 24 h post-administration of [211At]PSMA-5 (9 MBq/kg). Blood tests and histopathological examinations were performed at the end of the observation period. Blood tests in mice indicated no significant myelosuppression or renal dysfunction. However, the monkeys displayed mild leukopenia 24 h post-administration. Despite the high accumulation in the kidneys and thyroid, histological analysis revealed no abnormalities. On day 1, dose-dependent single-cell necrosis/apoptosis was observed in the salivary glands of mice and intestinal tracts of both mice and monkeys. Additionally, tingible body macrophages in the spleen and lymph nodes indicated phagocytosis of apoptotic B lymphocytes. Cortical lymphopenia (2/10) in the thymus and a decrease in the bone marrow cells (9/10) were observed in the 35 MBq/kg group in mice. These changes were transient, with no irreversible toxicity observed in mice 14 days post-administration. This study identified no severe toxicities associated with [211At]PSMA-5, highlighting its potential as a next-generation targeted alpha therapy for prostate cancer. The sustainable production of 211At using a cyclotron supports its applicability for clinical use. [ABSTRACT FROM AUTHOR]

131I is an important radioisotope in nuclear medicine, but due to the inherent defects of wet separation technology，the separation of 131I from uranium fission products (UFPs) has serious environmental pollution and low extraction efficiency. Considering the high yield of 131I in UFPs, it is necessary to develop a new method for separating 131I from UFPs, because it can not only expand the ways to obtain 131I, but also improve the utilization efficiency of UFPs. Unlike the traditional wet chemical separation technique, 131I was separated from UFPs by dry distillation in present work. Three stages worked under different temperatures, such as powdered the target, dry distillation and heat preservation, were involved in the separation process, so as to acquire as much as 131I from the target. The effect of dry distillation temperature on 131I separation efficiency was systematically investigated, it was found that the separation efficiency of 131I was higher than 98% when the distillation temperature was over 950 ℃. Moreover, it was also observed that both radioiodine and 103Ru were sublimated from the UFPs at the optimum distillation condition, but only radioiodine existed in the product. In order to explain this phenomenon, a detailed analysis of the iodine separation process was carried out. By combining the experimental results with the theoretical calculations, the separation mechanism of radioiodine from 103Ru was estimated as: 103Ru volatilized from the UFPs through the formation of RuO4, the volatile compound of 103Ru may be decomposed into RuO2 during the migration because of the high temperature in the heating tube, and then settled down. Therefore, to separate 131I from UFPs by dry distillation and obtain 131I product with high radiochemical purity, it is necessary to rationally plan the separation process, at the same time, the scientifically design of the heating tube length is also meaningful.

Karst rocky desertification (KRD) has become the most serious ecological disaster in the southwest of China and is a major obstacle to the sustainable development of the karst region in the southwest. Remarkably, scientific understanding of the spatial-temporal evolution of rocky desertification and the corresponding driving mechanism is the primary prerequisite crucial to controlling rocky desertification. Hence, the typical rocky desertification area of Qujing City, located in the upper reaches of the Yangtze River, was selected as the research object. On the basis of the Google Earth Engine (GEE) cloud platform and decision tree classification, the spatial-temporal evolution process of rocky desertification in Qujing City from 1990 to 2020 was investigated, and the driving factors of rocky desertification were explored in terms of the natural environment and socio-economic aspects. Consequently, over this period, the area of rocky desertification had decreased by 1728.38 km2, while the no rocky desertification area had increased by 1936.61 km2. Notably, the major driving factors of rocky desertification were fractional vegetation cover (FVC) (q = 0.41), land use type (q = 0.26), slope (q = 0.21), and land reclamation rate (q = 0.21). Typically, rocky desertification is likely to occur in areas with moderate or low FVC (<0.7), a low slope (0–8°) or high slope (35°–80°), a land type of cultivated-land or grassland, and a land reclamation rate of 10–70%. In addition, all two-factor interactions acted as drivers that exacerbate rocky desertification. Furthermore, FVC ∩ slope (q = 0.79) and slope ∩ land use type (q = 0.56) were two interacting drivers that promote rocky desertification strongly. [ABSTRACT FROM AUTHOR]

To observe the γ rays emitted from the low-lying isomeric state of 229Th (229mTh), we aim to dope fluoride crystals with its precursor 229Pa. In this study, we produced 229Pa by a 30 MeV proton bombardment on 232Th and developed a chemical separation method. The chemical yield of Pa was 93(4)%, and the physical production yield of 229Pa for the proton energy range of 29.0–30.1 MeV was measured to be 9.4(8) MBq/µAh, which was more than 10 times higher than those of 232,230,228,233Pa. These high chemical and production yields will allow us to prepare fluoride crystals having a sufficient amount of 229Pa for the observation of the γ rays of 229mTh. [ABSTRACT FROM AUTHOR]