|Hypersensitivity is the excessive, undesirable reactions produced by the normal immune system. Hypersensitivity reactions mediated by T cells can be activated by modified self -proteins, or by injected proteins. Allergic hypersensitivity occurs when an individual, who has produced IgE antibody in response to an antigen, or allergen, gets exposed to the same allergen. These allergen triggers the activation of IgE-binding mast cells in the exposed tissue, leading to a series of responses that are characteristic of allergy. The most common allergens include airborne allergens such as grass, tree or weed pollen, as well as moulds.
Open access to the scientific literature means the removal of barriers (including price barriers) from accessing scholarly work. There are two parallel roads towards open access: Open Access articles and self-archiving. Open Access articles are immediately, freely available on their Web site, a model mostly funded by charges paid by the author (usually through a research grant). The alternative for a researcher is self-archiving (i.e., to publish in a traditional journal, where only subscribers have immediate access, but to make the article available on their personal and/or institutional Web sites (including so-called repositories or archives)), which is a practice allowed by many scholarly journals.
Open Access raises practical and policy questions for scholars, publishers, funders, and policymakers alike, including what the return on investment is when paying an article processing fee to publish in an Open Access articles, or whether investments into institutional repositories should be made and whether self-archiving should be made mandatory, as contemplated by some funders.