Strongly typed heterogeneous collections

A heterogeneous collection is a datatype that is capable of storing data of different types, while providing operations for look-up, update, iteration, and others. There are various kinds of heterogeneous collections, differing in representation, invariants, and access operations. We describe HList --- a Haskell library for strongly typed heterogeneous collections including extensible records. We illustrate HList's benefits in the context of type-safe database access in Haskell. The HList library relies on common extensions of Haskell 98. Our exploration raises interesting issues regarding Haskell's type system, in particular, avoidance of overlapping instances, and reification of type equality and type unificatio

Strongly typed heterogeneous collections

A heterogeneous collection is a datatype that is capable of storing data of different types, while providing operations for look-up, update, iteration, and others. There are various kinds of heterogeneous collections, differing in representation, invariants, and access operations. We describe HList --- a Haskell library for strongly typed heterogeneous collections including extensible records. We illustrate HList's benefits in the context of type-safe database access in Haskell. The HList library relies on common extensions of Haskell 98. Our exploration raises interesting issues regarding Haskell's type system, in particular, avoidance of overlapping instances, and reification of type equality and type unificatio

Quantum-chemical investigation of the structure and the antioxidant properties of α-lipoic acid and its metabolites

Quantum-chemical computations were used to investigate the structure–antioxidant parameter relationships of α-lipoic acid and its natural metabolites bisnorlipoic acid and tetranorlipoic acid in their oxidized and reduced forms. The enantiomers of lipoic and dihydrolipoic acid were optimized using the B3LYP/6-311+G(3df,2p), B3LYP/aug-cc-pVDZ and MP2(full)/6-31+G(d,p) levels of theory as isolated molecules and in the presence of water. The geometries of the metabolites and the values of their antioxidant parameters (proton affinity, bond dissociation enthalpy, adiabatic ionization potential, spin density, and the highest occupied molecular orbital energy) were calculated at the B3LYP/6-311+G(3df,2p) level of theory. The results obtained reveal similarities between these structures: a pentatomic, nonaromatic ring is present in the oxidized forms, while an unbranched aliphatic chain (as found in saturated fatty acids) is present in both the oxidized and the reduced forms. Analysis of the spin density and the highest occupied molecular orbital energy revealed that the SH groups exhibited the greatest electron-donating activities. The values obtained for the proton affinity, bond dissociation enthalpy and adiabatic ionization potential indicate that the preferred antioxidant mechanisms for α-lipoic acid and its metabolites are sequential proton loss electron transfer in polar media and hydrogen atom transfer in vacuum

Phlebologie an deutschen Hautkliniken: eine Bestandsaufnahme im Auftrag der Deutschen Gesellschaft für Phlebologie

Reich-Schupke S, Alm J, Altmeyer P, et al. Phlebologie an deutschen Hautkliniken: Eine Bestandsaufnahme im Auftrag der Deutschen Gesellschaft für Phlebologie. Hautarzt. 2013;64(9):685-694.Phlebologic diseases have become extremely common and have major socio-economic impact. However, the percentage of dermatologists working in phlebology appears to be decreasing according to the data of the German Society of Phlebology (DGP). To investigate the reasons for this development, we-on behalf of the DGP-sent a questionnaire to 120 German Departments of Dermatology in autumn 2012. In 76 returned questionnaires, the number of physicians with additional fellowship training in phlebology averaged 1.5; the average number of those who fulfill the criteria for training fellows in phlebology was 0.9. In 71.1 % of the departments there was a phlebologist. A special phlebologic outpatient clinic existed in 73.7 % of the departments. Sonography with Doppler (89.5 %) and duplex (86.8 %) was used as the most frequent diagnostic tool. For therapy, compression (94.7 %), sclerotherapy (liquid 78.9 %, foam 63.2 %, catheter 18.4 %), endoluminal thermic procedures (radio wave 28.9 %, laser 17.1 %) and surgery (especially crossectomy and stripping 67.1 %, phlebectomy of tributaries 75 %) were used. The average number of treatments was very heterogenous in the different departments. Phlebology definitely plays an important role in dermatology. Most departments fulfill the formal criteria for the license to conduct advanced training in phlebology. A wide spectrum of phlebological diagnostic and therapeutic procedures is available.Hintergrund Venenleiden sind eine Volkskrankheit und haben eine enorme sozioökonomische Bedeutung. Dennoch scheint der Anteil der phlebologisch tätigen Dermatologen entsprechend den Zahlen der Deutschen Gesellschaft für Phlebologie (DGP) abzunehmen. Methoden Um die Ursachen dieser Entwicklung zu untersuchen, führten wir im Herbst 2012 im Auftrag der DGP eine Befragungsstudie zur Phlebologie an 120 deutschen Hautkliniken durch. Ergebnisse In 76 antwortenden Klinien gab es im Mittel 1,5 Phlebologen und 0,9 Ärzte mit Voraussetzungen zur Weiterbildungsermächtigung Phlebologie. In 71,1 % der Kliniken gab es einen Phlebologen, in 73,7 % eine phlebologische Sprechstunde. Zur Diagnostik wurden besonders die Doppler- (89,5 %) und Duplexsonographie (86,8 %) eingesetzt. In der Therapie führte die Kompressionstherapie (94,7 %), gefolgt von Sklerosierungstherapien (flüssig 78,9 %, Schaum 63,2 %, Katheter 18,4 %), den endoluminalen thermischen Verfahren (Radiowelle 28,9 %, Laser 17,1 %) und den operativen Eingriffen (vor allem Cross- und Saphenektomie 67,1 %, Seitenastexhairese 75 %). Die durchschnittlichen Behandlungszahlen waren sehr heterogen. Schlussfolgerung Die Phlebologie spielt in der Dermatologie weiterhin eine wichtige Rolle. Mehrheitlich sind in den Kliniken die Möglichkeiten zur Weiterbildung Phlebologie gegeben. Es wird ein breites Spektrum an phlebologischen Techniken zur Diagnostik und Therapie angeboten