488 research outputs found
High Temperature Corrosion of Nickel Based Heat Resistant Alloys and their Diffusion Brazed Parts(Materials, Metallurgy & Weldability)
A Note on Commutative Gelfand Theory for Real Banach Algebras
Pfaffenberger and Phillips [2] consider a real and unital case of the classical commutative Gelfand theorem and obtain two representation theorems. One is to represent a unital real commutative Banach algebra A as an algebra of continuous functions on the unital homomorphism space ΦA. The other is to represent A as an algebra of continuous sections on the maximal ideal space MA. In this note, we point out that similar theorems for non-unital case hold and show that two representation theorems are essentially identical.</p
Venous Thromboembolism After Removal of Retrievable Inferior Vena Cava Filters
The purpose of this study was to examine the incidence of new or recurrent venous thromboembolism (VTE) after retrieval of inferior vena cava (IVC) filters and risk factors associated with such recurrence. Between March 2001 and September 2008, at our institution, implanted retrievable vena cava filters were retrieved in 76 patients. The incidence of new or recurrent VTE after retrieval was reviewed and numerous variables were analyzed to assess risk factors for redevelopment of VTE after filter retrieval. In 5 (6.6%) of the 76 patients, redevelopment or worsening of VTE was seen after retrieval of the filter. Three patients (4.0%) had recurrent deep venous thrombosis (DVT) in the lower extremities and 2 (2.6%) had development of pulmonary embolism, resulting in death. Although there was no significant difference in the incidence of new or recurrent VTE related to any risk factor investigated, a tendency for development of VTE after filter retrieval was higher in patients in whom DVT in the lower extremities had been so severe during filter implantation that interventional radiological therapies in addition to traditional anticoagulation therapies were required (40% in patients with recurrent VTE vs. 23% in those without VTE; p = 0.5866 according to Fisher’s exact probability test) and in patients in whom DVT remained at the time of filter retrieval (60% in patients with recurrent VTE vs. 37% in those without VTE; p = 0.3637). In conclusion, new or recurrent VTE was rare after retrieval of IVC filters but was most likely to occur in patients who had severe DVT during filter implantation and/or in patients with a DVT that remained at the time of filter retrieval. We must point out that the fatality rate from PE after filter removal was high (2.6%)
DNA Damage Stress and Inhibition of Jak2-V617F Cause Its Degradation and Synergistically Induce Apoptosis through Activation of GSK3β
The cytoplasmic tyrosine kinase Jak2 plays a crucial role in cytokine receptor signaling in hematopoietic cells. The activated Jak2-V617F mutant is present in most cases of BCR/ABL-negative myeloproliferative neoplasms and constitutively activates downstream signals from homodimeric cytokine receptors, such as the erythropoietin receptor (EpoR). Here we examine the effects of DNA damage stress on Jak2 or Jak2-V617F and on induction of apoptosis in hematopoietic cells. Etoposide or doxorubicin dose-dependently decreased the expression level of Jak2 in UT7 or 32D cells expressing EpoR in the absence of Epo and that of exogenously expressed Jak2-V617F in UT7 cells when cotreated with the Jak2 inhibitor JakI-1 or AG490. Studies with pharmacological inhibitors and genetic manipulations further showed that downregulation of the PI3K/Akt pathway leading to the activation of GSK3β may be involved in downregulation of Jak2 or Jak2-V617F as well as in synergistic induction of Bax activation and apoptosis. The downregulation of Jak2 was inhibited by the proteasome inhibitor MG132 or by expression of both of loss-of-function mutants of c-Cbl and Cbl-b, E3 ubiquitin ligases which facilitated ubiquitination of Jak2-V617F when co-expressed in 293T cells. The pan-caspase inhibitor Boc-d-fmk also inhibited the Jak2 downregulation as well as appearance of a 100-kDa fragment that contained the N-terminal portion of Jak2 in response to DNA damage. Together, these data suggest that DNA damage stress with simultaneous inhibition of the kinase activity causes degradation of Jak2 or Jak2-V617F by caspase cleavage and proteasomal degradation through GSK3β activation, which is closely involved in synergistic induction of apoptosis in hematopoietic cells
Misorientation dependence of intergranular embrittlement of Cu-2.0 wt.% Sb bicrystals
Bicrystals of a Cu–2.0 wt.% Sb alloy with different [0 0 1] symmetric tilt boundaries were tensile tested at several temperatures from 77 to 743 K. The dependence of Sb segregation level at [0 0 1] tilt boundaries on the misorientation angle also was examined by energy-dispersive X-ray spectroscopy. The fracture behavior was sensitive to the misorientation angle and test temperature. Both the fracture behavior at 77 K and the Sb segregation level showed a good correlation with the grain-boundary energy of pure Cu. The higher the grain-boundary energy, the higher the Sb segregation level and the higher the degree of grain-boundary embrittlement
Röntgenographische Untersuchungen Über den Ausscheidungsvorgang in einer Kupfer-Beryllium-Legierung und den Einfluss von Magnesium- oder Zink-Zusätzen auf ihr Verhalten
Die Untersuchungen über das Ausscheidungsverhalten von Kupfer-1.8 Gew. -% Beryllium Legierungen ohne und mit etwa 0.2 Atom. -% Magnesium oder Zink wurden röntgenographisch mittels Laue-, Kleinwinkel-Streuung-, Einkristall-Schwenk-, und Debye-Scherrer- Aufnahmen durchgeführt. Die Kinetik der Ausscheidung kann wie folgt dargestellt werden: G.P.-Zonen auf {100} Flächen des α- Mischkristalls, Zwischenphase-γ' mit einem Zonenzustand, und Gleichgewichtsphase-r. Bei der magnesiumhaltigen Legierung hemmt die Abnahme der Übersättigung des Mischkristalls an Beryllium-Atomen zufolge einer bedeutenden Ausscheidung der Zwischenphase-γ' die diskontinuierliche Ausscheidung. Andererseits wird bei der zinkhaltigen Legierung das Wachstum der G.P.-Zonen aktiv, und die feineren Aus-scheidungsteilchen der γ'-Phase, die in dieser Arbeit γ'-Zonen bezeichnet werden, können nicht größer werden. Die mehren übersättigten Beryllium-Atome und die Spannung um die G.P.-Zonen und die γ'-Zonen verursachen die diskontinuierliche Ausscheidung. Für die beschleunigte Bilding der G.P.-Zonen bei Zusätzen von Magnesium oder Zink kann dahingehend gedeutet werden, daß sich die bei der Zonen-Bildung Spannungen durch diese Elemente vermindern, und daß die bei der Zonen-Bildung behilflichen Leerstellen in diesen Legierungen stabiler werden
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