Application of a biotin functionalized QD assay for determining available binding sites on electrospun nanofiber membrane

<p>Abstract</p> <p>Background</p> <p>The quantification of surface groups attached to non-woven fibers is an important step in developing nanofiber biosensing detection technologies. A method utilizing biotin functionalized quantum dots (QDs) 655 for quantitative analysis of available biotin binding sites within avidin immobilized on electrospun nanofiber membranes was developed.</p> <p>Results</p> <p>A method for quantifying nanofiber bound avidin using biotin functionalized QDs is presented. Avidin was covalently bound to electrospun fibrous polyvinyl chloride (PVC 1.8% COOH w/w containing 10% w/w carbon black) membranes using primary amine reactive EDC-Sulfo NHS linkage chemistry. After a 12 h exposure of the avidin coated membranes to the biotin-QD complex, fluorescence intensity was measured and the total amount of attached QDs was determined from a standard curve of QD in solution (total fluorescence vs. femtomole of QD 655). Additionally, fluorescence confocal microscopy verified the labeling of avidin coated nanofibers with QDs. The developed method was tested against 2.4, 5.2, 7.3 and 13.7 mg spray weights of electrospun nanofiber mats. Of the spray weight samples tested, maximum fluorescence was measured for a weight of 7.3 mg, not at the highest weight of 13.7 mg. The data of total fluorescence from QDs bound to immobilized avidin on increasing weights of nanofiber membrane was best fit with a second order polynomial equation (R²= .9973) while the standard curve of total fluorescence vs. femtomole QDs in solution had a linear response (R²= .999).</p> <p>Conclusion</p> <p>A QD assay was developed in this study that provides a direct method for quantifying ligand attachment sites of avidin covalently bound to surfaces. The strong fluorescence signal that is a fundamental characteristic of QDs allows for the measurement of small changes in the amount of these particles in solution or attached to surfaces.</p

Stopping Variables in Online Buying Processes: An Innovation Diffusion Approach

In this empirical study, variables that discriminate between consumers who search online but buy offline and consumers who search and buy online using Internet and the World Wide Web are identified using the innovation diffusion framework. Results show that, across eight product categories, mainly two variables discriminate between the two groups of consumers: self-assessed skill level and perceived transaction security

A study of the system of handling emergency requests in the home service department, Boston Metropolitan Chapter, American Red Cross

Thesis (M.S.)--Boston University, 1944. This item was digitized by the Internet Archive

Mission Completion, Troop Welfare and Destructive Idealism: A Case Study on the Phenomenology of a Combat Veteran’s Social Reintegration

Post-traumatic Stress Disorder (PTSD) among combat veterans remains an urgent and intractable problem for those who have served in the wars in Iraq and Afghanistan. In this paper, we argue that one of the reasons that combat related PTSD remains so difficult to treat is because psychologists - and American culture at large - do not fully understand it yet. It is our contention that there are two contributing factors that currently hinder our ability to successfully treat combat related PTSD. The first is a failure to look critically at the theoretical underpinnings that ground our current understanding of the disorder. The second related issue is our tendency to look to reductionist explanations and treatments. We use the theoretical framework of phenomenology alongside a case study of a man we call James in order to present this argument

Dynamic Prediction of retail Website Visitors\u27 Intentions

This paper presents a model for identifying general intentions of consumers visiting a retail website. When visiting a transactional website, consumers have various intentions such as browsing (i.e., no purchase intention), purchasing a product in the near future, or purchasing a particular product during their current visit. By predicting these intentions early in the visit, online merchants could personalize their offer to better fulfill the needs of consumers. We propose a simple model which enables classifying visitors according to their intentions after only four traversals (clicks). The model is based solely on navigation patterns which can be automatically extracted from clickstream. The results are presented and extensions of the model are proposed

Fate of Ascaris at various pH, temperature and moisture levels

Soil-transmitted helminths (STH) are intestinal worms that infect 24% of the world’s population. Stopping the spread of STH is difficult, as the eggs are resilient (can withstand high pH) and persistent (can remain viable in soils for several years). To ensure that new sanitation systems can inactivate STH, a better understanding of their resilience is required. This study assessed the inactivation of Ascaris eggs under various conditions, in terms of moisture content (MC) (90%), temperature (20–50 C) and pH (7–12.5). The results highlight that the exposure of Ascaris eggs to elevated pH (10.5–12.5) at temperatures 27.5 C for >70 days had no effect on egg viability. Compounding effects of alkaline pH (10.5) or decreasing MC (&lt;20%) was observed at 35 C, with pH having more of an effect than decreasing MC. To accelerate the inactivation of STH, an increase in the treatment temperature is more effective than pH increase. Alkaline pH alone did not inactivate the eggs but can enhance the effect of ammonia, which is likely to be present in organic wastes