Metal-Induced Fluorescence Quenching in Carbon Dots for Sensing Applications

Overexposure to metals can induce adverse health and environmental effects, thus monitoring metal concentrations is crucial. While current detection techniques are highly sensitive, they come at elevated costs, which limit their global use. As such, cheap and accessible sensors, providing both sensitivity and selectivity, are in high demand. With high surface area-to-volume ratios, tunable fluorescence and surface chemistries, nanoparticles are under investigation for development as metal sensors. However, many challenges exist including photobleaching, toxicity and a lack of selectivity. Owing to their low cytotoxicity, water-dispersibility and photostability, carbon dots have emerged as interesting alternatives. These amorphous carbon-based particles are ~10 nm in diameter and mainly composed of carbon, oxygen and hydrogen. While they have been investigated in metal sensing applications, the focus remains primarily on the application rather than the fundamental understanding of the mechanism of carbon dot-metal interactions in solution. In this work, we study the synthesis of carbon dots using several cheap and accessible precursors resulting in a surface decorated with functional groups such as amines, carboxylic acids and thiols. Following extensive purification protocols aimed at removing impurities that could bind to metal cations, we evaluate how these surface groups impact metal-carbon dot interactions. We demonstrate that some of our systems evidence sensitivity to Pb2+ and Hg2+ and exploit our knowledge of charge density and hard-and-soft acid-base theory to explain these findings and the underlying mechanism. This work provides a better understanding of metal-carbon dot interactions, which can allow us to design more sensitive and selective optical probes

Neglected and underutilized plant species in the Shouf-Aley area of Lebanon : an ethnobotanical study

Meeting: Regional Workshop : "Biodiversity as Food", Beirut, 3-5 February, 2006PowerPoint presentatio

Professional-to-professional exchange relationships and their impact on oncology referral patterns and patient outcomes

University of Technology Sydney. Faculty of Health.This thesis sought to understand inter-professional exchange relationships between referrers (General Practitioners [GPs] to Specialist Medical Providers [SMPs], and amongst SMPs) in the oncology context, and the impact of these relationships on referral behaviours, processes, and patient outcomes. A pragmatic-critical qualitative methodology, informed by social exchange (SET) and relational models (RMT) theories, was employed to explore this phenomenon. A descriptive method was taken to data collection, which relied upon a qualitative interview approach. Twenty GPs and 20 SMP were interviewed. The thesis identified how trust, collaboration, reciprocity, and communication regulated inter-professional referral relationships among medical professionals; and how accessibility, cost, patient experience, competitive advantage, high value care (HVC) and medical error can impact oncology patient outcomes. Findings were contextualised to the ‘here and now’ via the lens of medical professionalism. Themes arising from the data were tested against current and seminal research, and areas for change were identified. These relate to improving patient access, promoting HVC, and reducing medical error. Trust was found to be fundamentally important to the quality and longevity of the interprofessional referral relationship. Trust’s key role in the exchange relationships presents a concern, as the more trusted a SMP, the longer the waitlist/wait time is likely to be, hence impacting on time-to-treatment, which has a cascading effect on HVC, and medical error. A trust versus accessibility conundrum was identified, which highlighted the need for improvements in communication and accessibility among medical players, whilst continuing to practice evidenced-based-medicine, as well as the need for referral systems to be more patient-centric. The trust/accessibility ‘dilemma’ has not until now been identified as the basis of research or discussed in general terms, in relevant health and medical service literature. Solutions proffered include adopting an open-referral process; improving GP education in oncology to promote accurate referrals; designing and implementing a comprehensive referral form; and developing a national specialist database