Tuning the optical properties of silicon quantum dots via surface functionalization with conjugated aromatic fluorophores

The authors acknowledge Karen Nygard at UWO Biotron for assistance with confocal microscopy. This work was financially supported by NSERC Canada Discovery (Charpentier).Silicon Quantum Dots (SQDs) have recently attracted great interest due to their excellent optical properties, low cytotoxicity, and ease of surface modification. The size of SQDs and type of ligand on their surface has a great influence on their optical properties which is still poorly understood. Here we report the synthesis and spectroscopic studies of three families of unreported SQDs functionalized by covalently linking to the aromatic fluorophores, 9-vinylphenanthrene, 1-vinylpyrene, and 3-vinylperylene. The results showed that the prepared functionalized SQDs had a highly-controlled diameter by HR-TEM, ranging from 1.7–2.1 nm. The photophysical measurements of the assemblies provided clear evidence for efficient energy transfer from the fluorophore to the SQD core. Fӧrster energy transfer is the likely mechanism in these assemblies. As a result of the photogenerated energy transfer process, the emission color of the SQD core could be efficiently tuned and its emission quantum efficiency enhanced. To demonstrate the potential application of the synthesized SQDs for bioimaging of cancer cells, the water-soluble perylene- and pyrene-capped SQDs were examined for fluorescent imaging of HeLa cells. The SQDs were shown to be of low cytotoxicity.Publisher PDFPeer reviewe

Participatory Epidemiology of Endemic Diseases in West African Cattle – Ethnoveterinary and Bioveterinary Knowledge in Fulani Disease Control

Fulani pastoralists in Nigeria lack adequate access to good quality veterinary services and often resort to treating their animals themselves. There are several negative aspects to this, including poor treatment outcomes, misuse of veterinary drugs and subsequent resistance, and further barriers to good relations between pastoralists and veterinary services. A participatory epidemiology survey was undertaken in Fulani communities, to examine their ability to diagnose and treat bovine diseases. Qualitative participatory epidemiology techniques including semi-structured interviews, ranking and participant and non-participant observations were used for data collection. Quantitative analysis to match Fulani disease descriptions to veterinary diseases was done by hierarchical clustering and multi-dimensional scaling. A concurrent parasitological survey for soil-transmitted parasites, trypanosomiasis and tick-borne diseases was undertaken to validate results.Fulani pastoralists displayed high levels of ethnoveterinary knowledge and good clinical diagnostic abilities. Diseases considered important by pastoralists included: hanta (CBPP); sammore (trypanosomiasis); boro (foot and mouth disease), gortowel (liver fluke), dauda (parasitic gastro-enteritis with bloody diarrhoea) and susa (parasitic gastro-enteritis). The parasitology survey supported the participatory epidemiology results but also showed a high prevalence of tick-borne diseases that were not mentioned by pastoralists in this study. The use of “hanta” to describe CBPP is important as the accepted translation is liver-fluke (hanta is the Hausa word for liver). Gortowel and dauda, two previously undescribed Fulfulde disease names have now been matched to liver fluke and PGE with bloody diarrhoea. Fulani showed low levels of bovine veterinary knowledge with mostly incorrect veterinary drugs chosen for treatment. Levels of ethno- and bio-veterinary knowledge and their application within pastoralist livestock healthcare practices are discussed. Keywords: Fulani, Pastoralist, Cattle, Participatory epidemiology, Participatory diagnosis, Ethnoveterinary knowledg

Participatory Epidemiology of Endemic Diseases in West African Cattle – Ethnoveterinary and Bioveterinary Knowledge in Fulani Disease Control

Fulani pastoralists in Nigeria lack adequate access to good quality veterinary services and often resort to treating their animals themselves. There are several negative aspects to this, including poor treatment outcomes, misuse of veterinary drugs and subsequent resistance, and further barriers to good relations between pastoralists and veterinary services. A participatory epidemiology survey was undertaken in Fulani communities, to examine their ability to diagnose and treat bovine diseases. Qualitative participatory epidemiology techniques including semi-structured interviews, ranking and participant and non-participant observations were used for data collection. Quantitative analysis to match Fulani disease descriptions to veterinary diseases was done by hierarchical clustering and multi-dimensional scaling. A concurrent parasitological survey for soil-transmitted parasites, trypanosomiasis and tick-borne diseases was undertaken to validate results.Fulani pastoralists displayed high levels of ethnoveterinary knowledge and good clinical diagnostic abilities. Diseases considered important by pastoralists included: hanta (CBPP); sammore (trypanosomiasis); boro (foot and mouth disease), gortowel (liver fluke), dauda (parasitic gastro-enteritis with bloody diarrhoea) and susa (parasitic gastro-enteritis). The parasitology survey supported the participatory epidemiology results but also showed a high prevalence of tick-borne diseases that were not mentioned by pastoralists in this study. The use of “hanta” to describe CBPP is important as the accepted translation is liver-fluke (hanta is the Hausa word for liver). Gortowel and dauda, two previously undescribed Fulfulde disease names have now been matched to liver fluke and PGE with bloody diarrhoea. Fulani showed low levels of bovine veterinary knowledge with mostly incorrect veterinary drugs chosen for treatment. Levels of ethno- and bio-veterinary knowledge and their application within pastoralist livestock healthcare practices are discussed. Keywords: Fulani, Pastoralist, Cattle, Participatory epidemiology, Participatory diagnosis, Ethnoveterinary knowledg