170 research outputs found

    Field Telemetry of Blade-rotor Coupled Torsional Vibration at Matuura Power Station Number 1 Unit

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    The quasi-modal reduction technique and finite element model (FEM) were used to construct an analytical model for the blade-rotor coupled torsional vibration of a steam turbine generator of the Matuura Power Station. A single rotor test was executed in order to evaluate umbrella vibration characteristics. Based on the single rotor test results and the quasi-modal procedure, the total rotor system was analyzed to predict coupled torsional frequencies. Finally, field measurement of the vibration of the last stage buckets was made, which confirmed that the double synchronous resonance was 124.2 Hz, meaning that the machine can be safely operated. The measured eigen values are very close to the predicted value. The single rotor test and this analytical procedure thus proved to be a valid technique to estimate coupled torsional vibration

    Effect of continuous cisternal cerebrospinal fluid drainage for patients with thin subarachnoid hemorrhage

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    External cerebrospinal fluid (CSF) drainage is an effective method to remove massive subarachnoid hemorrhage (SAH), but carries the risk of meningitis and shunt-dependent hydrocephalus. This study investigated whether postoperative cisternal CSF drainage affects the incidence of cerebral vasospasm and clinical outcome in patients with thin SAH. Seventy-eight patients with thin SAH, 22 men and 56 women aged from 17 to 73 years (mean 51.2 years), underwent surgical repair for ruptured anterior circulation aneurysm. Patients were divided into groups with (38 patients) and without (40 patients) postoperative cisternal CSF drainage, and the incidences of angiographical and symptomatic vasospasm, shunt-dependent hydrocephalus, meningitis, and the clinical outcome were compared. The incidences of angiographical vasospasm (31.6% vs 50.0%), symptomatic vasospasm (7.9% vs 12.5%), shunt-dependent hydrocephalus (5.3% vs 0%), and meningitis (2.6% vs 0%) did not differ between patients with and without cisternal CSF drainage. All patients in both groups resulted in good recovery. Postoperative cisternal CSF drainage does not affect the incidence of cerebral vasospasm or the clinical outcome in patients with thin SAH

    Hemorrhagic infarction at 33 days after birth in a healthy full-term neonate

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    Intraparenchymal hemorrhage in the full-term neonate rarely occurs more than 2 weeks after birth, and its definitive cause remains unclear. In the present report, a case of a patient with intraparenchymal hemorrhage occurring 33 days after birth is described. Histological examination of the brain tissue obtained during hematoma evacuation through craniotomy showed hemorrhagic infarction. Patent foramen ovale may have been present and this may have led to spontaneous paradoxical cerebral embolism followed by hemorrhagic infarction

    Purification of matrix Gla protein from a marine teleost fish, Argyrosomus regius: Calcified cartilage and not bone as the primary site of MGP accumulation in fish

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    Matrix Gla protein (MGP) belongs to the family of vitamin K-dependent, Gla-containing proteins, and in mammals, birds, and Xenopus, its mRNA was previously detected in extracts of bone, cartilage, and soft tissues (mainly heart and kidney), whereas the protein was found to accumulate mainly in bone. However, at that time, it was not evaluated if this accumulation originated from protein synthesized in cartilage or in bone cells because both coexist in skeletal structures of higher vertebrates and Xenopus. Later reports showed that MGP also accumulated in costal calcified cartilage as well as at sites of heart valves and arterial calcification. Interestingly, MGP was also found to accumulate in vertebra of shark, a cartilaginous fish. However, to date, no information is available on sites of MGP expression or accumulation in teleost fishes, the ancestors of terrestrial vertebrates, who have in their skeleton mineralized structures with both bone and calcified cartilage. To analyze MGP structure and function in bony fish, MGP was acid-extracted from the mineralized matrix of either bone tissue (vertebra) or calcified cartilage (branchial arches) from the bony fish, Argyrosomus regius,(1) separated from the mineral phase by dialysis, and purified by Sephacryl S-100 chromatography. No MGP was recovered from bone tissue, whereas a protein peak corresponding to the MGP position in this type of gel filtration was obtained from an extract of branchial arches, rich in calcified cartilage. MGP was identified by N-terminal amino acid sequence analysis, and the resulting protein sequence was used to design specific oligonucleotides suitable to amplify the corresponding DNA by a mixture of reverse transcription-polymerase chain reaction (RT-PCR) and 5'rapid amplification of cDNA (RACE)-PCR. In parallel, ArBGP (bone Gla protein, osteocalcin) was also identified in the same fish, and its complementary DNA cloned by an identical procedure. Tissue distribution/accumulation was analyzed by Northern blot, in situ hybridization, and immunohistochemistry. In mineralized tissues, the MGP gene was predominantly expressed in cartilage from branchial arches, with no expression detected in the different types of bone analyzed, whereas BGP mRNA was located in bone tissue as expected. Accordingly, the MGP protein was found to accumulate, by immunohistochemical analysis, mainly in the extracellular matrix of calcified cartilage. In soft tissues, MGP mRNA was mainly expressed in heart but in situ hybridization, indicated that cells expressing the MGP gene were located in the bulbus arteriosus and aortic wall, rich in smooth muscle and endothelial cells, whereas no expression was detected in the striated muscle myocardial fibers of the ventricle. These results show that in marine teleost fish, as in mammals, the MGP gene is expressed in cartilage, heart, and kidney tissues, but in contrast with results obtained in Xenopus and higher vertebrates, the protein does not accumulate in vertebra of non-osteocytic teleost fish, but only in calcified cartilage. In addition, our results also indicate that the presence of MGP mRNA in heart tissue is due, at least in fish, to the expression of the MGP gene in only two specific cell types, smooth muscle and endothelial cells, whereas no expression was found in the striated muscle fibers of the ventricle. In light of these results and recent information on expression of MGP gene in these same cell types in mammalian aorta, it is likely that the levels of MGP mRNA previously detected in Xenopus, birds, and mammalian heart tissue may be restricted toregions rich in smoot Our results also emphasize the need to re-evaluate which cell types are involved in MGP gene expression in other soft tissues and bring further evidence that fish are a valuable model system to study MGP gene expression and regulation.NIAMS NIH HHS [AR25921]info:eu-repo/semantics/publishedVersio

    Matrix gla protein in xenopus laevis: molecular cloning, tissue distribution, and evolutionary considerations

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    Matrix Gla protein (MGP) belongs to the family of vitamin K-dependent, Gla-containing proteins and in higher vertebrates, is found in the extracellular matrix of mineralized tissues and soft tissues. MGP synthesis is highly regulated at the transcription and posttranscription levels and is now known to be involved in the regulation of extracellular matrix calcification and maintenance of cartilage and soft tissue integrity during growth and development. However, its mode of action at the molecular level remains unknown. Because there is a large degree of conservation between amino,acid sequences of shark and human MGP, the function of MGP probably has been conserved throughout evolution. Given the complexity of the mammalian system, the study of MGP in a lower vertebrate might be advantageous to relate the onset of MGP expression with specific events during development. Toward this goal, MGP was purified from Xenopus long bones and its N-terminal amino acid sequence was determined and used to clone the Xenopus MGP complementary DNA (cDNA) by a mixture of reverse-transcription (RT)- and 5'- rapid amplification of cDNA ends (RACE)-polymerase chain reaction (PCR). MGP messenger RNA (mRNA) was present in all tissues analyzed although predominantly expressed in Xenopus bone and heart and its presence was detected early in development at the onset of chondrocranium development and long before the appearance of the first calcified structures and metamorphosis. These results show that in this system, as in mammals, MGP may be required to delay or prevent mineralization of cartilage and soft tissues during the early stages of development and indicate that Xenopus is an adequate model organism to further study MGP function during growth and development.NATO/CRG940751/SA5.2.05, Praxis XXI/BIA 469/94, (NIH; grant AR 25921) (Praxis XXI/BPD/18816) (Praxis XXI/BICJ-2985

    Sturgeon osteocalcin shares structural features with matrix gla protein evolutionary relationship and functional implications

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    Osteocalcin (OC) and matrix Gla protein (MGP) are considered evolutionarily related because they share key structural features, although they have been described to exert different functions. In this work, we report the identification and characterization of both OC and MGP from the Adriatic sturgeon, a ray-finned fish characterized by a slow evolution and the retention of many ancestral features. Sturgeon MGP shows a primary structure, post-translation modifications, and patterns of mRNA/protein distribution and accumulation typical of known MGPs, and it contains seven possible Gla residues that would make the sturgeon protein the most gamma-carboxylated among known MGPs. In contrast, sturgeon OC was found to present a hybrid structure. Indeed, although exhibiting protein domains typical of known OCs, it also contains structural features usually found in MGPs (e. g. a putative phosphorylated propeptide). Moreover, patterns of OC gene expression and protein accumulation overlap with those reported for MGP; OC was detected in bone cells and mineralized structures but also in soft and cartilaginous tissues. We propose that, in a context of a reduced rate of evolution, sturgeon OC has retained structural features of the ancestral protein that emerged millions of years ago from the duplication of an ancient MGP gene and may exhibit intermediate functional features.Portuguese Science and Technology Foundation [POCTI/MAR/57921/2004, SFRH/BD/9077/2002]; Fundo Europeu De Desenvolvimento Regional (FEDER) (Portugal); National Funding; Center of Marine Sciences (CCMAR

    Matrix gla protein in turbot (Scophthalmus maximus): gene expression analysis and identification of sites of protein accumulation

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    Matrix Gla protein (Mgp) is a secreted vitamin K-dependent extracellular matrix protein and a physiological inhibitor of calcification whose gene structure, amino acid sequence and tissue distribution have been conserved throughout evolution. In the present work, the turbot (Scophthalmus maximus) mgp cDNA was cloned and the sequence of the deduced protein compared to that of other vertebrates. As expected, it was closer to teleosts than to other vertebrate groups but there was a strict conservation of amino-acids thought to be important for protein function. Analysis of mgp gene expression indicated branchial arches as the site with higher levels of expression, followed by heart, vertebra and kidney. These results were confirmed by in situ hybridization with a strong mgp expression in branchial arch chondrocytes. Mgp was found to accumulate in gills where it appeared to be restricted to chondrocytes from branchial filaments, while in vertebrae it was localized in vertebral end plates, in growth zones, in vertebral arches and spines and in notochord cells. In the soft tissues analysed, Mgp was mainly detected in kidney and heart, consistent with previous data and providing further evidence for a role of Mgp as a calcification inhibitor and a modulator of the mineralization process. Our studies provide evidence that turbot, an important new species for aquaculture, is also a useful model to study function and expression of Mgp

    The interplay between mineral metabolism, vascular calcification and inflammation in Chronic Kidney Disease (CKD): challenging old concepts with new facts

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    Chronic kidney disease (CKD) is one of the most powerful predictors of premature cardiovascular disease (CVD), with heightened susceptibility to vascular intimal and medial calcification associated with a high cardiovascular mortality. Abnormal mineral metabolism of calcium (Ca) and phosphate (P) and underlying (dys)regulated hormonal control in CKD-mineral and bone disorder (MBD) is often accompanied by bone loss and increased vascular calcification (VC). While VC is known to be a multifactorial process and a major risk factor for CVD, the view of primary triggers and molecular mechanisms complexity has been shifting with novel scientific knowledge over the last years. In this review we highlight the importance of calcium-phosphate (CaP) mineral crystals in VC with an integrated view over the complexity of CKD, while discuss past and recent literature aiming to highlight novel horizons on this major health burden. Exacerbated VC in CKD patients might result from several interconnected mechanisms involving abnormal mineral metabolism, dysregulation of endogenous calcification inhibitors and inflammatory pathways, which function in a feedback loop driving disease progression and cardiovascular outcomes. We propose that novel approaches targeting simultaneously VC and inflammation might represent valuable new prognostic tools and targets for therapeutics and management of cardiovascular risk in the CKD population.Portuguese Foundation for Science and Technology (UID/Multi/04326/2019); Portuguese Society of Nephrology (SPN)info:eu-repo/semantics/publishedVersio

    「私は父を知らなかった」 : ポール・オースターの『ムーン・パレス』と『ミスター・ヴァーティゴ』における父子関係

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    Paul Austerʼs Moon Palace and Mr. Vertigo have often been defined as “frontier novels” because they are both set in the American West. However, due to the overt attention paid to the milieu, critics of these works have not completely analyzed the shared theme of father-son relationships. A careful analysis of the two works reveals that Moon Palace depicts main characters who aspire to become father figures butultimately fail to do so. In contrast, the protagonistʼs act of levitation in Mr. Vertigo, one of its biggest motifs, is depicted as an indicator of his moral development and degradation, which is heavily influenced by the father-son relationship that he establishes as “master and apprentice.” Based on this inference, this study demonstrates that the protagonistʼs eventual signs of re-levitation in Mr. Vertigo lead to the realization of an unsatisfied desire to become a father figure in Moon Palace
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