Effects of Geometrical Uncertainties on Electrocardiography

This paper investigates the influence of uncertainties in geometrical coordinates on calculated torso and epicardial potentials. Two types of sources, spherical epicardial and multipolar, are both considered. A concentric sphere model with the epicardial surface represented by a unit sphere and the torso surface represented by a spherical surface of radius 1.4 is utilized. While the representation of biological surfaces with spheres is a highly idealized situation, the dimensions chosen and the approximations utilized are such that the results should be indicative of those using measured biological coordinates.     

Effect of hot-air drying on flavour compounds of bell peppers (Capsicum annuum)

The influence of hot-air drying on the composition of both volatile and non-volatile flavour compounds of different Dutch bell pepper cultivars was investigated. Contents of glucose, fructose, ascorbic, citric, and oxalic acid decreased significantly after drying, while the levels of sucrose, malic, fumaric, and cis-aconitic acid increased. Glucose, fructose and ascorbic acid probably participate in Maillard reactions during heating. Different effects of drying could be distinguished on the composition of volatile compounds. The majority of these compounds evaporated during drying. Some compounds were partly retained in the dried bell peppers, whereas others disappeared completely. Gas chromatography-sniffing port analysis revealed that compounds with mainly “fresh” odour notes like lettuce/grassy/green bell pepper ((Z-2-3-hexenal), fruity/almond ((E)-2-hexenal), fruity (octanal), lettuce/green bell pepper ((Z)-3-hexenol), and grassy/green bell pepper ((Z)-2-hexenal) decreased or disappeared after drying. Another group of compounds increased or were formed during drying, like 4-octen-3-one, (E)-2-heptenal, (E)-2-octenal, (E,Z)- and (E,E)-2,4-heptadienal, decanal, and (E)-2-nonenal; most are known as autoxidation products of unsatu-rated fatty acids. The increased levels of 2-methylpropionic and 2- and 3-methylbutyric acid, 2-metlhylpropanal, and 2- and 3-methylbutanal seemed to be due to Strecker degradation. Gas chromatography-sniffing port analysis showed that the latter three compounds had distinct cacao, sweaty, and spicy odour characteristics.     

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on early life stages of the pike (Esox lucius L.)

Freshly fertilized pike eggs were exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at concentrations of 0.1, 1.0 and 10 ppt (ng/liter) for 96 hours. At all concentrations examined egg development was retarded by 23%, and the growth of fry was also significantly retarded for a long period after exposure. A dose-related mortality was observed. Highest mortality rates occurred during resorption of the yolk and reached almost 100 percent at a concentration of 10 ppt. Death was preceded by development of severe generalized edemas.Histopathologically edemas and hemorrhages were observed, together with alterations of bloodvessel walls. In the liver, two stages of pathological changes were distinguished. The first was characterized by a dilation of sinusoids and a slight swelling of hepatocyte nuclei; in the second stage the nuclei were enlarged up to twice the normal diameter. Hepatocytes were degenerated and varied in size and shape and liver architecture was a almost completely lost.     

Einsatzbereich des Werkstoffes Glas in der Anlagentechnik

Scope of glass as material of construction in plant engineering. In conjunction with PTFE as sealing material, borosilicate glass is nowadays recognized as a material for plant construction. A complete modular system of individual components with suitable connecting pieces is available. Moreover, a variety of equipment has been developed for accomplishing various processes while paying due attention to the special material properties of the material glass. In combination with other materials, primarily in the field of heat exchangers and evaporators, numerous processes are now conducted without any difficulty in glass plant. In this range of processes, a special place is assumed by those which urgently require glass for corrosion reasons, such as chlorination or bromination reactions or concentration of acids, because specialized know-how is sometimes required.