All Optical Implementation of Multi-Spin Entanglement in a Semiconductor Quantum Well

We use ultrafast optical pulses and coherent techniques to create spin entangled states of non-interacting electrons bound to donors (at least three) and at least two Mn2+ ions in a CdTe quantum well. Our method, relying on the exchange interaction between localized excitons and paramagnetic impurities, can in principle be applied to entangle a large number of spins.Comment: 17 pages, 3 figure

In vivo time-gated fluorescence imaging with biodegradable luminescent porous silicon nanoparticles

Fluorescence imaging is one of the most versatile and widely used visualization methods in biomedical research. However, tissue autofluorescence is a major obstacle confounding interpretation of in vivo fluorescence images. The unusually long emission lifetime (5-13 mu s) of photoluminescent porous silicon nanoparticles can allow the time-gated imaging of tissues in vivo, completely eliminating shorter-lived (<10 ns) emission signals from organic chromophores or tissue autofluorescence. Here using a conventional animal imaging system not optimized for such long-lived excited states, we demonstrate improvement of signal to background contrast ratio by 450-fold in vitro and by 420-fold in vivo when imaging porous silicon nanoparticles. Time-gated imaging of porous silicon nanoparticles accumulated in a human ovarian cancer xenograft following intravenous injection is demonstrated in a live mouse. The potential for multiplexing of images in the time domain by using separate porous silicon nanoparticles engineered with different excited state lifetimes is discussed

Total Treatment of Black and Grey Water for Rural Communities

Decentralized or on-site treatment systems for domestic waste and wastewater treatment can be the answer to many of the world’s environmental health problems. Poor or remote communities need technologies developed for the application, and an economically viable whole-of-waste approach is necessary. Vermicomposting offers a natural option to treat domestic waste and wastewater into reusable products. The extent of treatment can be incorporated into the design, providing flexibility and scalability required for the user community