Self-Excitation Mechanisms in Paper Calenders Formulated as a Stability Problem

In one of the last stages of paper production the surface of the paper is refined in calenders. The paper is compressed in the nip by rollers which sometimes tend to exhibit self-excited vibrations. These vibrations may lead to wear and dramatically reduce the durability of the expensive rollers. The reason for the self-excited vibrations is to be found in the interaction of the rollers with the paper. The interaction process in the nip is very complex and has not been completely understood from a mechanical point of view. The purpose of this paper is to develop simple mechanical models of the nip which can lead to an explanation of the phenomenon

Dringliche Eingriffe in der endokrinen Chirurgie

Während Notfalloperationen aus mechanischer Indikation immer wieder vorkommen (z. B. Chiasma-Syndrom, Atemwegsobstruktion), sind die kritischen Überfunktionen der endokrinen Drüsen in der Regel durch konservativ-medikamentöse Therapie ausreichend zu beherrschen. Ausnahmen: z. B. thyreotoxische Krise (bei nur kurz anhaltender Besserung durch Plasmapherese bei einer jodinduzierten Hyperthyreose) oder akutes Cushing-Syndrom (nicht beherrschbare hypokaliämische Alkalose). Solche Einzelfälle hängen von der optimalen Kooperation von Anaesthesie, Chirurgie und internistischer Intensivmedizin ab. Gesetze der Diagnose und der konservativen Vorbereitung für die operative Behandlung von endokrinen Überfunktionszuständen nur ultima ratio übertreten!Urgent surgery for emergency situations in endocrine diseases is needed for mechanical problems (e.g., chiasma syndrome or tracheal obstruction) and very rarely for endocrine hyperfunction, which can usually be treated by nonsurgical means. Exceptions are patients suffering from thyroid storm (impending early relapse after plasmapheresis due to excess iodine) or from acute Cushing's syndrome (intractable potassium loss and alkalosis whom we have successfully transferred to surgery. The rules for diagnosis and medical preparation for surgery of endocrine hyperfunctional states should only be disregarded ultima ratio

Relation of gallbladder function and Helicobacter pylori infection to gastric mucosa inflammation in patients with symptomatic cholecystolithiasis

Background. Inflammatory alterations of the gastric mucosa are commonly caused by Helicobacter pylori (Hp) infection in patients with symptomatic gallstone disease. However, the additional pathogenetic role of an impaired gallbladder function leading to an increased alkaline duodenogastric reflux is controversially discussed. Aim:To investigate the relation of gallbladder function and Hp infection to gastric mucosa inflammation in patients with symptomatic gallstones prior to cholecystectomy. Patients: Seventy-three patients with symptomatic gallstones were studied by endoscopy and Hp testing. Methods: Gastritis classification was performed according to the updated Sydney System and gallbladder function was determined by total lipid concentration of gallbladder bile collected during mainly laparoscopic cholecystectomy. Results: Fifteen patients revealed no, 39 patients mild, and 19 moderate to marked gastritis. No significant differences for bile salts, phospholipids, cholesterol, or total lipids in gallbladder bile were found between these three groups of patients. However, while only 1 out of 54 (< 2%) patients with mild or no gastritis was found histologically positive for Hp, this infection could be detected in 14 (74%) out of 19 patients with moderate to marked gastritis. Conclusion: Moderate to marked gastric mucosa inflammation in gallstone patients is mainly caused by Hp infection, whereas gallbladder function is not related to the degree of gastritis. Thus, an increased alkaline duodenogastric reflux in gallstone patients seems to be of limited pathophysiological relevance. Copyright (c) 2006 S. Karger AG, Basel

Pancreatic B-Cell Peptides as Parameters for Diagnosis and Localisation of Hormone Secreting Tumours

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