Multivariable non-linear controller for a synchronous generator

The problem of multivariable controller synthesis for a turbogenerator is considered. Using the feedback linearization approach for multi-input non-linear systems, the existence of a linearizing state feedback for the improved reduced-order model of a turbogenerator is proved and the simplest form of this feedback is derived. Application of the obtained non-linear controller to the multivariable control of a turbogenerator provides very good results not only for the reduced-order model but also for the ‘exact’ (Park's) model of a turbogenerator. Simulations of fault and post-fault conditions in the obtained nonlinear control system confirm its superiority over a system with a voltage regulator and power system stabilizer.     

Volvulus of the sigmoid colon. Emergency resection and anastomosis]

Eleven cases of sigmoid volvulus in patients aged 76 years in average, without visible signs of necrosis on endoscopy, are reported. All patients were treated within 6 to 48 hours by colic resection and immediate restoration of continuity with a mechanical anastomosis. Morbidity was low, including one case of evisceration and one of pneumonia, and there was no mortality after three months. Early resection seems to prevent the risks of necrosis and recurrence, and to have a good prognosis for survival.     

Changes in intra-abdominal pressure and central venous and brain venous blood pressure in patients during extracorporeal circulation.

BACKGROUND: The aim was to analyze IAP changes and the relationships between IAP, CVP, and brain venous blood pressure, which are still unknown, in patients undergoing coronary artery bypass grafting (CABG) with extracorporeal circulation. MATERIAL/METHODS: Twenty-five male patients (aged 53-67 years) underwent CABG under general anesthesia with normovolemic hemodilution. IAPs were measured in the urinary bladder, CVP by left internal jugular vein cannulation, and brain venous blood pressure by retrograde cannulation of the right jugular vein bulb (JVP, jugular vein pressure) at seven time-points: 1) after induction of anesthesia before the operation, 2) during internal thoracic artery preparation, 3) 10 minutes after heart-lung machine disconnection, 4) after procedure completion, before sending the patient to the intensive postoperative care unit, 5) one hour after the procedure, 6) 6 hours after the procedure, and 7) 18 hours after the procedure. RESULTS: IAP increased from points 3 to 6. CVP increased from points 3, 4, and 5 and decreased at point 7. Similar changes were noted in JVP. There were significant correlations between IAP and CVP at points 1, 2, 3, 4, and 5, IAP and JVP at points 3, 4, and 5, and CVP and JVP at all points. The overall analysis showed correlations between IAP and CVP and JVP and very strong correlation between CVP and JVP. CONCLUSIONS: 1) CABG with extracorporeal circulation resulted in increases in IAP, CVP, and brain venous blood pressure. 2) The changes in CVP and brain venous blood pressure correlated with intra-abdominal pressure.     

Mapping the architecture of the ATP-binding site of the KATP channel subunit Kir6.2

ATP-sensitive potassium (K_ATP) channels comprise Kir6.2 and SUR subunits. The site at which ATP binds to mediate K_ATP channel inhibition lies on Kir6.2, but the potency of block is enhanced by coexpression with SUR1. To assess the structure of the ATP-binding site on Kir6.2, we used a range of adenine nucleotides as molecular measuring sticks to map the internal dimensions of the binding site. We compared their efficacy on Kir6.2–SUR1, and on a truncated Kir6.2 (Kir6.2ΔC) that expresses in the absence of SUR. We show here that SUR1 modifies the ATP-binding pocket of Kir6.2, by increasing the width of the groove that binds the phosphate tail of ATP, without changing the length of the groove, and by enhancing interaction with the adenine ring.     

Über die Rolle von Makrophagen in der Pathogenität des Vacciniavirus für junge Ratten

Zusammenfassung Das Vacciniavirus vermehrt sich schnell in den Organen von 1 tägigen Ratten, und die Tiere verenden am 2. oder 3. Tag nach der Infektion. In den Organen von 7 tägigen Ratten kann sich das Virus anfangs vermehren, später wird es aber eliminiert und die Tiere überleben. Bei 15tägigen Ratten wird das Virus eliminiert und die Tiere verenden nicht.Eintägige Ratten, die vor der Infektion Makrophagen erwachsener Tiere erhalten haben, kamen nicht ad exitum. Die Makrophagen von erwachsenen Ratten haben im Gegensatz zu Makrophagen von jungen Tieren die Fähigkeit, das phagozytierte Virus zu inaktivieren.Es wird daraus der Schluß gezogen, daß für die hohe Empfindlichkeit junger Ratten gegenüber Vacciniavirusinfektionen die funktionelle Unreife ihrer Makrophagen verantwortlich ist.

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The role of macrophages in the pathogenicity of vaccinia virus for young rats

Summary Vaccinia viruses grew rapidly in organs of 1-day-old rats, and the animals died 2 or 3 days after infection. In the organs of 7-day-old rats the viruses replicated initially, but were later eliminated and the animals survived. The 15-day-old rats were capable of eliminating the viruses completely and did not die. When macrophages of adult animals were transferred to 1-day-old rats before infection the rats did not die. The macrophages of adult rats destroyed phagocytized viruses while those of young animals did not.The results suggest that this susceptibility of young rats to vaccinia virus infection is due to the functionally immature state of their macrophages.

     

Structural studies on Hafnia alvei 114-60 O-antigen.

The structure of Hafnia alvei 114-60 O-antigen has been established using sugar and methylation analyses as well as 1H-NMR spectroscopy. The results obtained proved that the repeating unit of Hafnia alvei 114-60 O-antigen is identical to that of Hafnia alvei ATCC 13337 standard strain and has the following structure: [formula: see text]     

Bacteriophage treatment of suppurative skin infections

The study material comprised 31 patients with chronic suppurative infections of the skin caused by Pseudomonas, Staphylococcus, Klebsiella, Proteus and Escherichia. Within 2-16 weeks of the treatment, an improvement of the general state was observed as well as suppression of the local inflammation, purification of a wound from the suppurative and necrotic content, faster healing of the ulcers and fully negative results of the bacteriologic tests. In 16 cases, an outstanding therapeutic effect was obtained, in 7 cases marked improvement was reported and in 2 a transitory improvement was reported. In 7 patients the treatment was abandoned due to the lack of improvement (1 case) or development of side effects (6 cases). The results obtained provide evidence for the high effectiveness of phage therapy in the treatment of suppurative skin infections.