Integration of UAV and GF-2 Optical Data for Estimating Aboveground Biomass in Spruce Plantations in Qinghai, China

More refined and economical aboveground biomass (AGB) monitoring techniques are needed because of the growing significance of spruce plantations in climate change mitigation programs. Due to the challenges of conducting field surveys, such as the potential inaccessibility and high cost, this study proposes a convenient and efficient alternative to traditional field surveys that integrates Gaofen-2 (GF-2) satellite optical images and unmanned aerial vehicle (UAV)-acquired optical and point cloud data to provide a reliable and refined estimation of the aboveground biomass (AGB) in spruce plantations. The feasibility of using data produced from the semiautomatic processing of UAV-based images and photogrammetric point clouds to replace conventional field surveys of sample plots in a young spruce plantation was evaluated. The AGB in 53 sample plots was estimated using data extracted from the UAV imagery. The UAV plot data and GF-2 optical data were used in four regression models to estimate the AGB in the study area. The coefficient of determination (R2), root-mean-square error (RMSE), mean percent standard error (MPSE), and Lin’s concordance correlation coefficient (LCCC) were calculated through five-fold cross-validation and stratified random sampling to evaluate the models’ efficacies. In the end, the most accurate model was used to generate the spatial distribution map of the AGB. The results revealed the following: (1) the individual-tree height (R2 = 0.90) and crown diameter (R2 = 0.74) extracted from UAV data were accurate enough to replace field surveys used to obtain the AGB at the plot levels; (2) the random forest (RF) model (R2 = 0.86; RMSE = 1.75 t/ha; MPSE = 15.75%; LCCC = 0.91) outperformed the ordinary least-squares (OLS) model (R2 = 0.68; RMSE = 2.49 t/ha; MPSE = 22.94%; LCCC = 0.81), artificial neural network (ANN) model (R2 = 0.67; RMSE = 2.54 t/ha; MPSE = 21.48%; LCCC = 0.80), and support vector machine (SVM) model (R2 = 0.60; RMSE = 2.84 t/ha; MPSE = 31.73%; LCCC = 0.76) in terms of the estimation accuracy; (3) an AGB map generated by the random forest model was in good agreement with field surveys and the age of the spruce plantations. Therefore, the method proposed in this study can be used as a refined and cost-effective way to estimate the AGB in young spruce plantations

Photoinduced Synthesis of Methylated Marine Cyclopeptide Galaxamide Analogs with Isoindolinone as Anticancer Agents

The methylation of amino acid residues has played an important role in the biological function of bioactive peptides. In this paper, various methyl-modified and stereostructural-modified marine cyclopeptide galaxamide analogs with isoindolinone were synthesized by a photoinduced single electron transfer cyclization reaction. It was found that the single-methyl substitution was beneficial for the bioactivity of cyclic analogs with isoindolinone fragments, and the influence of methylation on bioactivity is uncertain and is sometimes case-specific. The compound with a single methyl group at Gly5 (compound 8) showed the strongest antiproliferative activity against HepG-2 cells. The tumor cell apoptosis, cell cycle, mitochondrial membrane potential, intracellular Ca2+ concentration and lactate dehydrogenase activity have been studied extensively to evaluate the antitumor potential of compound 8. Western blotting tests showed that compound 8 could decrease the MDM2 level and increase p53 levels efficiently. Careful molecular docking suggested that cyclic peptide 8 could bind firmly with MDM2 oncoprotein, indicating that MDM2 may be a potential drug target of the prepared peptides

A survey on Helicobacter pylori infection rate in Hainan Province and analysis of related risk factors

Abstract Objective The aim of this study was to understand the prevalence and potential risk factors of Helicobacter pylori (H. pylori) infection in Hainan Province, China. Methods We conducted this study in 21 health service stations in 5 cities of Hainan Province from August 2022 to April 2023. We selected the various participants based on a stratified whole-group sampling method. The 14C-UBT was used to analyze H. pylori infection in 3632 participants. We also analyzed the possible relationship between variables and H. pylori infection based on chi-square test and multifactorial logistic regression. The model was evaluated by performing a Hosmer–Lemeshow goodness-of-fit test and plotting receiver operating characteristic(ROC) curves. Results In total, the results of 3632 eligible participants (age: 14 to 93 years) were included in the analysis. The total prevalence of H. pylori infection in Hainan Province was approximately 38.7%. The prevalence of H. pylori infection was found to increase with age, stabilized in the age group of 45 to 64 years, but peaked in the age group of 65 years and older. In multifactorial analysis, the prevalence of H. pylori infection was positively associated with middle-aged adults (45–64 years), older adults (≥ 65 years), drinking, farmers, natural labor, routinely share utensils, have habit of frequent betel nut consumption, upper gastrointestinal symptoms, and family history of gastric cancer. The factors negatively associated with prevalence included family size ≤ 3, washing hands often before meals, frequent exercise, regular meals, and frequent consumption of fruits and vegetables. In addition, the Hosmer–Lemeshow test showed a good fit (χ2 = 12.983, P = 0.112) and the area under ROC was 0.631 (95%CI: 0.613 ~ 0.649). Conclusion The prevalence of H. pylori infection in Hainan Province was observed to be moderate and closely related to age, local socioeconomic conditions, hygienic status and dietary habits