Surface PEGylation of hollow mesoporous silica nanoparticles via aminated intermediate

A hybrid of organic/inorganic system, hollow mesoporous silica nanoparticles functionalized with poly(ethylene glycol), was synthesized in the presence of coupling agent and aminated ends. Doxorubicin (DOX) was used as a model drug to evaluate the effect of PEGylation on the loading capacity and release pattern of the system. Characterization with transmission electron microscopy (TEM) and scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption-desorption, thermogravimetric analysis (TGA) and Fourier transformed infrared (FTIR) confirmed the PEG conjugation, as well as the amorphous mesoporous nature of the synthesized particles. Due to the capping effect of PEG molecules over the pores in the silica structure, the synthesized system was able to retain higher amount of cargo and establish a controlled manner when releasing.     

Practical Contributions of the Systems-Based Evolutionary Learning Laboratory to Knowledge and Stakeholder Management

This paper reports on a case study on improving the quality of life for women smallholder farmers in Vietnam, using the systems-based Evolutionary Learning Laboratory (ELLab) approach. The study aims to provide evidence of practical contributions of the ELLab to project stakeholder and knowledge management through the case study. A transformative learning framework was developed to provide initial reflections on the planning phase of the project. Practical contributions of the ELLab process to stakeholder identification and management, and knowledge creation during project planning and implementation are discussed. Strong evidence was found of transformations in awareness and perspectives amongst project actors that subsequently led to systemic and executable action plans. This clearly proved the value of the ELLab approach in informal transformative learning.     

Rapid removal of Chernobyl fallout from Mediterranean surface waters by biological activity

The sinking of particulate organic matter from the euphotic zone is an important pathway for the vertical transport of many elements and organic compounds in the sea. Many natural and artificial radionuclides in surface waters are readily adsorbed onto suspended particles and are presumably scavenged and removed to depth on time scales commensurate with both particle sinking rate and retention time of the radionuclide on the particle. Previously, abyssal benthic organisms from the northeast Pacific were found to contain short-lived fission products which entered the sea surface as fallout from nuclear testing. The presence of these radionuclides at great depth could not be explained by Stokesian settling of small fallout particles and it was hypothesized that zooplankton grazing in the surface layers packaged these particle-reactive radionuclides into large, relatively dense faecal pellets which rapidly sank to depth. We report here data from a time-series sediment trap experiment and concomitant zooplankton collections which show conclusively that Chernobyl radioactivity, in particular the rare earth nuclides 141Ce and 144Ce, entering the Mediterranean as a single pulse, was rapidly removed from surface waters and transported to 200 m in a few days primarily by zooplankton grazing.     

Complex organic matter in Titan's atmospheric aerosols from in situ pyrolysis and analysis

Aerosols in Titan's atmosphere play an important role in determining its thermal structure. They also serve as sinks for organic vapours and can act as condensation nuclei for the formation of clouds, where the condensation efficiency will depend on the chemical composition of the aerosols. So far, however, no direct information has been available on the chemical composition of these particles. Here we report an in situ chemical analysis of Titan's aerosols by pyrolysis at 600 degrees C. Ammonia (NH3) and hydrogen cyanide (HCN) have been identified as the main pyrolysis products. This clearly shows that the aerosol particles include a solid organic refractory core. NH3 and HCN are gaseous chemical fingerprints of the complex organics that constitute this core, and their presence demonstrates that carbon and nitrogen are in the aerosols.