Jointless assembly of the stator core of the generator at the Sayano-Shushenskoe hydroelectric station

Conclusions The use of jointless assembly of the stator considerably complicates installation of the unit. It is far faster and simpler to assemble the stator from individual ready-made sectors. It is impossible to create on the assembly floor conditions for providing the required quality of assembling a jointless stator. The entire assembly process was performed in temporary structures — tents — in which it is difficult, and at times impossible in the case of combined assembly of the stator and turbine, to maintain a constant temperature and to keep out dust and precipitation.So far the advantages of a jointless stator have not been determined since at present the assembled units have 50–60% of the rated load. It is impossible to make any practical conclusions about an increase of core life. The test engineers of Elektrosila repeatedly measured vibrations and other characteristics of the stator. The results are positive, they are being generalized. It will be possible to make final conclusions when the units are operating at full capacity, but theoretically the jointless stator is indisputably progressive.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 7, pp. 15–17, July, 1982.     

Physical and functional interactions between the herpes simplex virus UL15 and UL28 DNA cleavage and packaging proteins

Herpes simplex virus (HSV) DNA is cleaved from concatemers and packaged into capsids in infected cell nuclei. This process requires seven viral proteins, including UL15 and UL28. UL15 expressed alone displays a nuclear localization, while UL28 remains cytoplasmic. Coexpression with UL15 enables UL28 to enter nuclei, suggesting an interaction between the two proteins. Additionally, UL28 copurified with UL15 from HSV-infected cells after ion-exchange and DNA affinity chromatography, and the complex sedimented as a 1:1 heterodimer upon sucrose gradient centrifugation. These findings are evidence of a physical interaction of UL15 and UL28 and a functional role for UL15 in directing UL28 to the nucleus.     

Endogenous synthesis of arginine plays an important role in maintaining arginine homeostasis in postweaning growing pigs

This study was conducted to determine whether endogenous synthesis of arginine plays a role in regulating arginine homeostasis in postweaning pigs. Pigs were fed a sorghum-based diet containing 0. 98% arginine and were used for studies at 75 d of age (28.4 kg body weight). Mitochondria were prepared from the jejunum and other major tissues for measuring the activities of Delta1-pyrroline-5-carboxylate (P5C) synthase and proline oxidase (enzymes catalyzing P5C synthesis from glutamate and proline, respectively) and of ornithine aminotransferase (OAT) (the enzyme catalyzing the interconversion of P5C into ornithine). For metabolic studies, jejunal enterocytes were incubated at 37 degrees C for 30 min in Krebs-Henseleit bicarbonate buffer containing 2 mmol/L L-glutamine, 2 mmol/L L-[U-14C]proline, and 0-200 micromol/L gabaculine (an inhibitor of OAT). The activities of P5C synthase, proline oxidase and OAT were greatest in enterocytes among all of the tissues studied. Incubation of enterocytes with gabaculine resulted in decreases (P < 0.05) in the synthesis of ornithine and citrulline from glutamine and proline. When gabaculine was orally administered to pigs (0.83 mg/kg body weight) to inhibit intestinal synthesis of citrulline from glutamine and proline, plasma concentrations of citrulline (-26%) and arginine (-22%) decreased (P < 0.05), whereas those of alanine (+21%), ornithine (+17%), proline (+107%), taurine (+56%) and branched-chain amino acids (+21-40%) increased (P < 0.05). On the basis of dietary arginine intake and estimated arginine utilization, the endogenous synthesis of arginine in the 28-kg pig provided >/=50.2% of total daily arginine requirement. Taken together, our results suggest an important role for endogenous synthesis of arginine in regulating arginine homeostasis in postweaning growing pigs, as previously shown in neonatal pigs.     

Telomeres, senescence and cellular radiation response

Telomeres shield the ends of chromosomes from degradation and end-to-end fusions. They shorten at each cell division and when they reach a critically short length, cells arrest in the G1 phase of the cell cycle and undergo senescence. This effectively limits the proliferative potential of cells. Senescence functions as a tumour suppressor mechanism and appears to contribute to the process of ageing. If senescence is circumvented by tumour viruses, proliferation is re-initiated until cells enter crisis. Activation of telomerase prevents telomere attrition and cells become immortal. Cellular response to ionizing radiation involves induction of cell cycle checkpoint arrests and programmed cell death. Because radiation produces double strand breaks in DNA, which cause telomere-less chromosome ends, radiation response appears to be the result of inappropriate induction of cellular senescence mechanisms.