University of California, Santa Barbara

About: University of California, Santa Barbara is a education organization based out in Santa Barbara, California, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 30281 authors who have published 80852 publications receiving 4626827 citations. The organization is also known as: UC Santa Barbara & UCSB.

Extinction and Ecosystem Function in the Marine Benthos

Abstract: Rapid changes in biodiversity are occurring globally, yet the ecological impacts of diversity loss are poorly understood. Here we use data from marine invertebrate communities to parameterize models that predict how extinctions will affect sediment bioturbation, a process vital to the persistence of aquatic communities. We show that species extinction is generally expected to reduce bioturbation, but the magnitude of reduction depends on how the functional traits of individual species covary with their risk of extinction. As a result, the particular cause of extinction and the order in which species are lost ultimately govern the ecosystem-level consequences of biodiversity loss.

Optimized Metal-Organic-Framework Nanospheres for Drug Delivery: Evaluation of Small-Molecule Encapsulation

Abstract: We have developed a general synthetic route to encapsulate small molecules in monodisperse zeolitic imid-azolate framework-8 (ZIF-8) nanospheres for drug delivery. Electron microscopy, powder X-ray diffraction, and elemental analysis show that the small-molecule-encapsulated ZIF-8 nanospheres are uniform 70 nm particles with single-crystalline structure. Several small molecules, including fluorescein and the anticancer drug camptothecin, were encapsulated inside of the ZIF-8 framework. Evaluation of fluorescein-encapsulated ZIF-8 nanospheres in the MCF-7 breast cancer cell line demonstrated cell internalization and minimal cytotoxicity. The 70 nm particle size facilitates cellular uptake, and the pH-responsive dissociation of the ZIF-8 framework likely results in endosomal release of the small-molecule cargo, thereby rendering the ZIF-8 scaffold an ideal drug delivery vehicle. To confirm this, we demonstrate that camptothecin encapsulated ZIF-8 particles show enhanced cell death, indicative of internaliza...

Predicted Releases of Engineered Nanomaterials: From Global to Regional to Local

Abstract: A key question for industry, regulators, toxicologists, and risk assessors working with nanomaterials is what relevant environmental engineered nanomaterial (ENM) concentrations should be considered. Answering this question requires ENM material flow estimates at the local level. Using a life-cycle approach, global ENM production and application data were used to estimate releases at global, regional, national, and local levels. Local level emissions were then used to estimate releases to water (direct and from wastewater treatment effluent), soils (direct and from runoff and biosolids), and air (direct and from incineration of ENM-containing products). Waste management data for dozens of countries were used to estimate the flow of 10 major ENMs through eight world regions. A national and local release example was conducted with data from the United States, providing predicted wastewater effluent concentrations for the San Francisco Bay area, ranging from low nanograms per liter to micrograms per liter de...

Assuring the quality of volunteered geographic information

Abstract: Volunteered geographic information (VGI) is a phenomenon of recent years, offering an alternative mechanism for the acquisition and compilation of geographic information. As such it offers substantial advantages, but suffers from a general lack of quality assurance. We discuss the issues involved in the determination of quality for geospatial data, and trace the history of research on VGI quality. We describe three approaches to quality assurance, which we term the crowd-sourcing, social, and geographic approaches respectively. We discuss the advantages and limitations of each, and the research that will be needed to operationalize the geographic approach.