RESUMEN
Comprehensive landscape patterns influence water quality with multiple factors, complex processes, and scale dependence. However, studies identifying landscape thresholds causing abrupt water quality changes and characterizing the contribution of topography to water quality are still limited. Exploring the impact mechanisms of natural geographical and landscape characteristics on spatial and seasonal water quality variations is conducive to watershed water resource protection and ecosystem restoration. Based on water quality monitoring data of Minjiahe River in the typical headwater area of the upstream Dan River in China from 2019 to 2021, we employed redundancy analysis, partial redundancy analysis, and nonparametric change-point analysis to analyze the relationship between stream water quality and multi-spatial scale comprehensive landscape patterns, to obtain the interactive and independent contributions of different landscape categories at multi-spatial scales on water quality, and to find the key landscape threshold leading to abrupt changes in water quality. Results showed that landscape configuration, landscape composition, and topographic factors collectively explain over 89.1% of water quality variation. Most seasonal variations in water quality were primarily caused by landscape configuration. The landscape composition was mainly responsible for the differences in water quality variations among spatial scales. The topographic factors made the least independent contribution and had a potential impact on overall water quality variation. In order to protect the water quality of streams, it is more reasonable to regulate the landscape at different scales. At the sub-catchment scale, interspersion and juxtaposition index (IJI) and landscape shape index (LSI) should be controlled below 82% and 22. At the 100 m riparian scale, farmland, urban land, IJI, and LSI should be controlled below 29%, 6.5%, 92%, and 26, respectively. Our results provide important guidance for optimizing landscape patterns and water conservation in the watershed.
Asunto(s)
Ecosistema , Calidad del Agua , Benchmarking , Ríos , China , Monitoreo del Ambiente/métodosRESUMEN
PEGylated uricase is a promising anti-gout drug, but the only commercially marketed 10kDa mPEG modified porcine-like uricase (Pegloticase) can only be used for intravenous infusion. In this study, tetrameric canine uricase variant was modified by covalent conjugation of all accessible É amino sites of lysine residues with a smaller 5kDa mPEG (mPEG-UHC). The average modification degree and PEGylation homogeneity were evaluated. Approximately 9.4 5 kDa mPEG chains were coupled to each monomeric uricase and the main conjugates contained 7-11 mPEG chains per subunit. mPEG-UHC showed significantly therapeutic or preventive effect on uric acid nephropathy and acute urate arthritis based on three different animal models. The clearance rate from an intravenous injection of mPEG-UHC varied significantly between species, at 2.61 mL/h/kg for rats and 0.21 mL/h/kg for monkeys. The long elimination half-life of mPEG-UHC in non-human primate (191.48 h, intravenous injection) indicated the long-term effects in humans. Moreover, the acceptable bioavailability of mPEG-UHC after subcutaneous administration in monkeys (94.21%) suggested that subcutaneous injection may be regarded as a candidate administration route in clinical trails. Non-specific tissue distribution was observed after administration of (125)I-labeled mPEG-UHC in rats, and elimination by the kidneys into the urine is the primary excretion route.
Asunto(s)
Artritis Experimental/prevención & control , Portadores de Fármacos , Supresores de la Gota/farmacocinética , Enfermedades Renales/prevención & control , Polietilenglicoles/química , Urato Oxidasa/farmacocinética , Animales , Artritis Experimental/inducido químicamente , Disponibilidad Biológica , Química Farmacéutica , Pollos , Modelos Animales de Enfermedad , Perros , Femenino , Supresores de la Gota/administración & dosificación , Supresores de la Gota/sangre , Supresores de la Gota/química , Supresores de la Gota/orina , Semivida , Haplorrinos , Humanos , Inyecciones Intravenosas , Inyecciones Subcutáneas , Enfermedades Renales/inducido químicamente , Lisina , Masculino , Tasa de Depuración Metabólica , Peso Molecular , Conejos , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/farmacocinética , Tecnología Farmacéutica/métodos , Distribución Tisular , Urato Oxidasa/administración & dosificación , Urato Oxidasa/sangre , Urato Oxidasa/química , Urato Oxidasa/orina , Ácido ÚricoRESUMEN
By the method of harvesting sampling trees, the information of aboveground biomass in 34 plots of a Larix olgensis plantation were collected, of which, the information from 29 plots was selected and fitted with stand factors and TM image RS factors, respectively to establish biomass models, and the information from the rest 5 plots was used to verify the models accuracy. The aboveground biomass in the Larix olgensis plantation could be linearly fitted with either stand factors or RS factors. For the young-middle aged trees, the estimation accuracy of stand factors model was higher (P(stand) = 94.33%), and the test error was smaller (MRE(stand) = 6%), compared with RS factors model (P(RS) = 92.32% , MRE(RS) = 31%). If only the middle-aged trees were taken into account, the estimation effect of the two models had no significant different (error sum E(stand) = 329.9 t, E(RS) = 313.6 t). Overall, the stand factors model was better for the estimation of Larix olgensis cortex, wood, and stumpage biomass, while the RS factors model was better for the estimation of middle-aged trees leaf, flower, fruit, branch, and crown biomass.