River monitoring from satellite radar altimetry in the Zambezi River basin

Satellite radar altimetry can be used to monitor surface water levels from space. While current and past altimetry missions were designed to study oceans, retracking the waveforms returned over land allows data to be retrieved for smaller water bodies or narrow rivers. The objective of this study is the assessment of the potential for river monitoring from radar altimetry in terms of water level and discharge in the Zambezi River basin. Retracked Envisat altimetry data were extracted over the Zambezi River basin using a detailed river mask based on Landsat imagery. This allowed for stage measurements to be obtained for rivers down to 80m wide with an RMSE relative to in situ levels of 0.32 to 0.72m at different locations. The altimetric levels were then converted to discharge using three different methods adapted to different data-availability scenarios: first with an in situ rating curve available, secondly with one simultaneous field measurement of cross-section and discharge, and finally with only historical discharge data available. For the two locations at which all three methods could be applied, the accuracies of the different methods were found to be comparable, with RMSE values ranging from 4.1 to 6.5% of the mean annual in situ gauged amplitude for the first method and from 6.9 to 13.8% for the second and third methods. The precision obtained with the different methods was analyzed by running Monte Carlo simulations and also showed comparable values for the three approaches with standard deviations found between 5.7 and 7.2% of the mean annual in situ gauged amplitude for the first method and from 8.7 to 13.0% for the second and third methods

Climate change impact on water resources availability – Case study of the Llobregat River basin (Spain)

International audienceClimate change may have significant consequences on water resources availability and management at the basin scale. This is particularly true for areas already suffering from water stress, such as the Mediterranean area. This work focuses on studying these impacts in the Llobregat basin supplying Barcelona’s region. Several climate projections, adapted to the spatiotemporal resolution of the study, have been combined with a daily hydrological model to estimate future water availability.Depending on the scenario and the time period, different assessment indicators like reliability and resilience show a future decrease in water resources (up to 40%), with drought periods more frequent. An additional uncertainty analysis has also shown a high variability of results (annual water availability ranging from 147 hm3/year to 274 hm3/year), thus making accurate projections difficult. Finally, the study illustrates how climate change could be taken into account to provide adaptative measures for the future

Macrophage-Targeting Poly(lactide-co-glycolic acid) Nanoparticles Decorated with Multifunctional Brush Polymers

This study examines the potential of poly(lactic-co-glycolic acid) (PLGA) nanoparticles functionalized with poly(zwitterion)-mannose brushes to target macrophages. Uptake studies with RAW 264.7 macrophages indicate that multiple mannose-binding sites in the grafted brushes facilitate interaction with the mannose receptor of the macrophages, resulting in approximately four times higher cellular uptake than nanoparticles with mannose monolayer coatings. To test the feasibility of the nanoparticles as long-circulating drug delivery vehicles, their multicomponent aggregation in blood plasma is analyzed using nanoparticle tracking analysis and compared to poly(ethylene glycol)-coated (PEGylated) particles, which are known to reduce aggregation. There is no significant difference in the aggregation behavior of the poly(zwitterion)-mannose grafted particles and the PEGylated control particles (≈760 particles in aggregates per 105 particles). In addition, the particle size in blood plasma is compared, which includes the protein corona, after 0, 8, and 15 h. Whereas there is no significant difference at longer time scales, the overall particle size of the poly(zwitterion)-mannose brush-grafted nanoparticles is ≈130 nm smaller than that of the PEGylated nanoparticles at shorter time scales, suggesting a smaller protein corona. All these results suggest that poly(lactic-co-glycolic acid nanoparticles functionalized with poly(zwitterion)-mannose brush grafts may be excellent candidates for targeted drug delivery to macrophages.In this study, the potential of poly(lactic-co-glycolic acid) nanoparticles with a functional coating of poly(zwitterion)-mannose brushes to target macrophages is examined. Furthermore, the aggregation behavior of the nanoparticles in blood plasma is evaluated to determine their potential to be employed as drug delivery vehicles.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/172791/1/ppsc202100284-sup-0001-SuppMat.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/172791/2/ppsc202100284_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/172791/3/ppsc202100284.pd

Nanoparticle Tracking Analysis of Polymer Nanoparticles in Blood Plasma

A successful drug delivery system must overcome complex biological barriers. For particles injected into the blood, one of the first and most critical barriers pertains to blood stability to circulate through the human body. To effectively design drug delivery vehicles, interactions between the particles and blood, as well as the aggregation behavior, must be understood. This work presents a method to analyze particle size and aggregation in blood plasma using a commercially available nanoparticle tracking analysis (NTA) system. As a model system, fluorescently labeled polystyrene nanoparticles are incubated in goat blood plasma and analyzed using NTA. The particles incubated in plasma are found to have a protein corona that is larger than what has been observed by dynamic light scattering (DLS) in diluted plasma. Particles that are decorated with a PEG layer are also found to have large protein coronas in undiluted plasma. Because NTA is based on a unique visualization method, large multicomponent aggregates could be observed and quantified in a manner not feasible with other techniques. PEGylation of the particles is found to decrease the multicomponent aggregation from 1000 ± 200 particles for unmodified to 200 ± 30 particles for 1K PEGylated per 1 × 105 total particles.Interaction between nanoparticles and proteins is one of the major limitations for drug delivery systems. This work presents a methodology based on nanoparticle tracking analysis (NTA) to characterize this interaction. Fluorescently labeled nanoparticles can be imaged using NTA to characterize the entire protein corona in undiluted plasma. Due to the unique visualization of NTA, multicomponent aggregation can also be quantified.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/168279/1/ppsc202100016.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168279/2/ppsc202100016-sup-0001-SuppMat.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168279/3/ppsc202100016_am.pd

Nanoparticle Tracking Analysis of Polymer Nanoparticles in Blood Plasma

A successful drug delivery system must overcome complex biological barriers. For particles injected into the blood, one of the first and most critical barriers pertains to blood stability to circulate through the human body. To effectively design drug delivery vehicles, interactions between the particles and blood, as well as the aggregation behavior, must be understood. This work presents a method to analyze particle size and aggregation in blood plasma using a commercially available nanoparticle tracking analysis (NTA) system. As a model system, fluorescently labeled polystyrene nanoparticles are incubated in goat blood plasma and analyzed using NTA. The particles incubated in plasma are found to have a protein corona that is larger than what has been observed by dynamic light scattering (DLS) in diluted plasma. Particles that are decorated with a PEG layer are also found to have large protein coronas in undiluted plasma. Because NTA is based on a unique visualization method, large multicomponent aggregates could be observed and quantified in a manner not feasible with other techniques. PEGylation of the particles is found to decrease the multicomponent aggregation from 1000 ± 200 particles for unmodified to 200 ± 30 particles for 1K PEGylated per 1 × 105 total particles.Interaction between nanoparticles and proteins is one of the major limitations for drug delivery systems. This work presents a methodology based on nanoparticle tracking analysis (NTA) to characterize this interaction. Fluorescently labeled nanoparticles can be imaged using NTA to characterize the entire protein corona in undiluted plasma. Due to the unique visualization of NTA, multicomponent aggregation can also be quantified.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/168279/1/ppsc202100016.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168279/2/ppsc202100016-sup-0001-SuppMat.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168279/3/ppsc202100016_am.pd