University of Basel

About: University of Basel is a education organization based out in Basel, Basel-Stadt, Switzerland. It is known for research contribution in the topics: Population & Transplantation. The organization has 25084 authors who have published 52975 publications receiving 2388002 citations. The organization is also known as: Universität Basel & Basel University.

Pharmacological characterization of designer cathinones in vitro

Abstract: Background and purpose: Designer beta-keto amphetamines (e.g., cathinones, "bath salts," and "research chemicals") have become popular recreational drugs, but their pharmacology is poorly characterized. Experimental approach: We determined the potencies of cathinones to inhibit dopamine (DA), noradrenaline (NA), and serotonin (5-hydroxytryptamine [5-HT]) transport into transporter-transfected human embryonic kidney 293 cells, DA and 5-HT efflux from monoamine-preloaded cells, and monoamine receptor binding affinity. Key results: Mephedrone, methylone, ethylone, butylone, and naphyrone act as nonselective monoamine uptake inhibitors, similar to cocaine. Mephedrone, methylone, ethylone, and butylone also release 5-HT, similar to 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) and other entactogens. Cathinone, methcathinone, and flephedrone act as preferential DA and NA uptake inhibitors and DA releasers, similar to amphetamine and methamphetamine. Pyrovalerone and 3,4-methylenedioxypyrovalerone (MDPV) are highly potent and selective DA and NA transporter inhibitors but unlike amphetamines do not release monoamines. The non-beta-keto amphetamines are trace amine-associated receptor 1 ligands, whereas cathinones are not. All cathinones showed high blood-brain barrier permeability in an in vitro model. Mephedrone and MDPV exhibited particularly high permeability. Conclusions and implications: Cathinones have considerable pharmacological differences that form the basis for their suggested classification into three groups. The predominant action of all cathinones on the DA transporter is likely associated with a considerable risk of addiction. (c) 2012 The Authors. British Journal of Pharmacology (c) 2012 The British Pharmacological Society.

Dynamic force spectroscopy of single DNA molecules

Abstract: To explore the analytic relevance of unbinding force measurements between complementary DNA strands with an atomic force microscope, we measured the forces to mechanically separate a single DNA duplex under physiological conditions by pulling at the opposite 5′-ends as a function of the loading rate (dynamic force spectroscopy). We investigated DNA duplexes with 10, 20, and 30 base pairs with loading rates in the range of 16–4,000 pN/s. Depending on the loading rate and sequence length, the unbinding forces of single duplexes varied from 20 to 50 pN. These unbinding forces are found to scale with the logarithm of the loading rate, which is interpreted in terms of a single energy barrier along the mechanical separation path. The parameters describing the energy landscape, i.e., the distance of the energy barrier to the minimum energy along the separation path and the logarithm of the thermal dissociation rate, are found to be proportional to the number of base pairs of the DNA duplex. These single molecule results allow a quantitative comparison with data from thermodynamic ensemble measurements and a discussion of the analytic applications of unbinding force measurements for DNA.

A standard stellar library for evolutionary synthesis - II. The M dwarf extension

Abstract: A standard library of theoretical stellar spectra intended for multiple synthetic photometry applications including spectral evolutionary synthesis is presented. The grid includes M dwarf model spectra, hence complementing the first library version established in Paper I (Lejeune et al. 1997). It covers wide ranges of fundamental parameters: : 50 000 K ~ 2000 K, : 5.5 , and : . A correction procedure is also applied to the theoretical spectra in order to provide color-calibrated flux distributions over a large domain of effective temperatures. For this purpose, empirical –color calibrations are constructed between 11500 K and 2000 K, and semi -empirical calibrations for non-solar abundances ( to +1.0) are established. Model colors and bolometric corrections for both the original and the corrected spectra, synthesized in the system, are given for the full range of stellar parameters. We find that the corrected spectra provide a more realistic representation of empirical stellar colors, though the method employed is not completely adapted to the lowest temperature models. In particular the original differential colors of the grid implied by metallicity and/or luminosity changes are not preserved below 2500 K. Limitations of the correction method used are also discussed.