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Register a new userSilver catalyzed Fluorouracil degradation; a promising new role for graphene
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Justin Wells Justin Wells
Publication date
2014
fields
Physics
and research's language is
English
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Chemotherapy treatment usually involves the delivery of fluorouracil (5-Fu) together with other drugs through central venous catheters. Catheters and their connectors are increasingly coated (or impregnated) with silver or argentic alloys/compounds. Complications such as broken catheters are common, leading to additional suffering for patients and increased medical costs. Here, we uncover a likely cause of such failure through a study of the surface chemistry relevant to chemotherapy drug delivery, i.e. between 5-Fu and silver. We show that silver catalytically decomposes 5-Fu, releasing HF as a product. This reaction compromises the efficacy of the treatment, and at the same time, releases HF which is damaging to both patient and catheter. Our study not only reveals an important reaction which has so far been overlooked, but additionally allows us to propose that graphene coatings inhibit such a reaction and offer superior performance for cancer treatment applications.
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Introducing an isolated intermediate band (IB) into a wide band gap semiconductor can potentially improve the optical absorption of the material beyond the Shockley-Queisser limitation for solar cells. Here, we present a systematic study of the thermodynamic stability, electronic structures, and optical properties of transition metals (M = Ti, V, and Fe) doped CuAlSe2 for potential IB thin film solar cells, by adopting the first-principles calculation based on the hybrid functional method. We found from chemical potential analysis that for all dopants considered, the stable doped phase only exits when the Al atom is substituted. More importantly, with this substitution, the IB feature is determined by $3d$ electronic nature of M^{3+} ion, and the electronic configuration of 3d^1 can drive a optimum IB that possesses half-filled character and suitable subbandgap from valence band or conduction band. We further show that Ti-doped CuAlSe2 is the more promising candidate for IB materials since the resulted IB in it is half filled and extra absorption peaks occurs in the optical spectrum accompanied with a largely enhanced light absorption intensity. The result offers a understanding for IB induced by transition metals into CuAlSe2 and is significant to fabricate the related IB materials.
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