Understanding Novel Superconductors with Ab Initio Calculations

This chapter gives an overview of the progress in the field of computational superconductivity. Following the MgB2 discovery (2001), there has been an impressive acceleration in the development of methods based on Density Functional Theory to compute the critical temperature and other physical properties of actual superconductors from first-principles. State-of-the-art ab-initio methods have reached predictive accuracy for conventional (phonon-mediated) superconductors, and substantial progress is being made also for unconventional superconductors. The aim of this chapter is to give an overview of the existing computational methods for superconductivity, and present selected examples of material discoveries that exemplify the main advancements.Comment: 38 pages, 10 figures, Contribution to Springer Handbook of Materials Modellin

Successful application of ancient DNA extraction and library construction protocols to museum wet collection specimens

Millions of scientific specimens are housed in museum collections, a large part of which are fluid preserved. The use of formaldehyde as fixative and subsequent storage in ethanol is especially common in ichthyology and herpetology. This type of preservation damages DNA and reduces the chance of successful retrieval of genetic data. We applied ancient DNA extraction and single stranded library construction protocols to a variety of vertebrate samples obtained from wet collections and of different ages. Our results show that almost all samples tested yielded endogenous DNA. Archival DNA extraction was successful across different tissue types as well as using small amounts of tissue. Conversion of archival DNA fragments into single-stranded libraries resulted in usable data even for samples with initially undetectable DNA amounts. Subsequent target capture approaches for mitochondrial DNA using homemade baits on a subset of 30 samples resulted in almost complete mitochondrial genome sequences in several instances. Thus, application of ancient DNA methodology makes wet collection specimens, including type material as well as rare, old or extinct species, accessible for genetic and genomic analyses. Our results, accompanied by detailed step-by-step protocols, are a large step forward to open the DNA archive of museum wet collections for scientific studies

Diamond electrodes: Diversity and maturity

Boron-doped diamond electrodes have attracted increasing interest from researchers due to their outstanding properties for electroanalysis and other electrochemical applications. Material quality and availability have come a long way since the initial reports on the basic electrochemical properties back in the late 1980s and early 1990s. In this review, we highlight how diamond electrochemistry has diversified and matured in recent years in terms of the understanding of structure-property relationships and the development of new applications of materials in electroanalytical chemistry. © Materials Research Society 2014

Electrochemical oxidation of Mn2+ on boron-doped diamond electrodes with Bi3+ used as an electron transfer mediator

Electrochemical oxidation of Mn2+ with and without the presence of Bi3+ was studied using voltammetric and in situ spectro-electrochemical techniques at boron-doped diamond (BDD) electrodes in 1.0 M HClO4. Electrochemical oxidation of only Mn2+ resulted in the formation of mostly MnO2 with MnO4- produced as a minor product. The MnO2 film formed on the electrode surface, which is an inevitable part of Mn2+ oxidation, shows a blocking effect on the formation of MnO4-, and reduces the overall current efficiency of MnO4- production. Higher Mn2+ concentrations result in less MnO4- production due to the formation of more MnO2. The addition of Bi3+ increased the current efficiency of MnO4- production. The Bi3+ is oxidized to Bi(V), which acts as an electrocatalyst in MnO4- production. The Bi(V) oxidizes MnO2, formed on the electrode surface, to MnO4-. This increases the production of MnO4- by removing the blocking film to provide an active electrode (bare BDD) surface, which is available for further Mn2+ oxidation. (C) 2004 The Electrochemical Society.open11713sciescopu