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21.
C Casali JF Obadia E Canet K Bendjelid X André-Fou?t D Revel MF Janier 《Canadian Metallurgical Quarterly》1997,32(11):713-720
RATIONALE AND OBJECTIVES: Validation of new positron emission tomography (PET) tracers or magnetic (MR) imaging contrast agents is based on isolated rodent heart preparations. The use of larger animals could provide a more direct validation using the devices used for humans. METHODS: An isolated pig heart preparation has been developed and adapted to the technical constraints of whole body PET and MR imaging. This preparation could be used either in the Langendorff or working mode after selective cannulation of both coronary arteries. RESULTS: The authors showed that quantification of regional kinetics of PET tracers was possible using this preparation by measuring fluorine-18-labeled deoxyglycose (18FDG) kinetics in remote and ischemic territories. Experiments using MR imaging contrast agents, for myocardial perfusion, demonstrated the ability of this preparation to accurately validate these contrast agents over a wide range of flow rates. CONCLUSIONS: An isolated pig heart preparation could be developed to fulfill the constraints of PET and MR imaging, and proved useful for the study of the distribution of different tracers or contrast media developed for functional cardiac imaging in humans. 相似文献
22.
The hydroxycarbonate of nickel and aluminium (Ni/ Al = 3) with a hydrotalcite-like structure is an outstanding precursor of the active component of supported nickel catalysts. Good mechanical strength and suitable nickel content of these catalysts, which are necessary for practical applications, can be achieved by mechanical mixing of this compound with an additional support. The catalyst prepared from a mixture of 56.5 wt-% of nickel-aluminium hydroxycarbonate and 43.5 wt-% of γ-alumina was proven to have a stable catalytic activity in the methanation reaction at 2 MPa and 800 K. 相似文献
23.
24.
Y Panis J Belghiti D Valla JP Benhamou F Fékété 《Canadian Metallurgical Quarterly》1994,115(3):276-281
BACKGROUND: In Budd-Chiari syndrome (BCS) treated by portosystemic shunt, postoperative shunt thrombosis is associated with high morbidity and mortality rates. The aim of this study was to determine factors associated with shunt thrombosis. METHODS: From 1985 to 1991, 25 patients underwent portosystemic shunt for BCS. According to the patency of the shunt during the postoperative period and follow-up, patients were divided into two groups including 17 patients with patent shunt and 8 (32%) with shunt thrombosis. RESULTS: In patients with patent shunt, actuarial survival rate at 5 years was 87% versus 38% in patients with shunt thrombosis (p < 0.05). Duration of symptoms before operation was higher in patients with shunt thrombosis than in patients with patent shunt (315 +/- 483 vs 109 +/- 168 days, p < 0.05). In patients with patent shunt, extensive fibrosis or cirrhosis was observed in 3 of 17 (18%) versus in 5 of 8 (63%) of patients with shunt thrombosis (p < 0.05). Shunt thrombosis was observed in 3 of 3 patients (100%) with the combination of myeloproliferative disorder, duration of symptoms more than 100 days, and cirrhosis versus 0 of 6 (0%) patients without this combination (p < 0.05). CONCLUSIONS: In acute form of BCS (with short history of the disease and absence of extensive fibrosis or cirrhosis), early portal decompression is mandatory, with low risk of shunt thrombosis and good long-term results. In chronic form of BCS, the risk of shunt thrombosis is high and long-term results are bad; in these patients, orthotopic liver transplantation must be considered. 相似文献
25.
Critics of Kohlberg's moral theory today focus on the content of his theory and more specifically on its justice-orientated moral concept. This has led to the well-known 'justice-care debate'. The purpose of this article is to critically examine the validity of Kohlberg's moral theory for research in nursing ethics from a caring perspective (referring to the content) as well as from a cognitive-structural perspective (referring to the basic assumptions of the model). The analysis points to the usefulness and value of the cognitive-structural model to empirically study nurses' ethical behaviour; the content of Kohlberg's model, however, needs to be adapted by adding a caring perspective as well as some personal and situational variables. An adjusted version of Kohlberg's model is proposed and discussed. 相似文献
26.
AR Reilein IS Tint NI Peunova GN Enikolopov VI Gelfand 《Canadian Metallurgical Quarterly》1998,142(3):803-813
We used melanophores, cells specialized for regulated organelle transport, to study signaling pathways involved in the regulation of transport. We transfected immortalized Xenopus melanophores with plasmids encoding epitope-tagged inhibitors of protein phosphatases and protein kinases or control plasmids encoding inactive analogues of these inhibitors. Expression of a recombinant inhibitor of protein kinase A (PKA) results in spontaneous pigment aggregation. alpha-Melanocyte-stimulating hormone (MSH), a stimulus which increases intracellular cAMP, cannot disperse pigment in these cells. However, melanosomes in these cells can be partially dispersed by PMA, an activator of protein kinase C (PKC). When a recombinant inhibitor of PKC is expressed in melanophores, PMA-induced pigment dispersion is inhibited, but not dispersion induced by MSH. We conclude that PKA and PKC activate two different pathways for melanosome dispersion. When melanophores express the small t antigen of SV-40 virus, a specific inhibitor of protein phosphatase 2A (PP2A), aggregation is completely prevented. Conversely, overexpression of PP2A inhibits pigment dispersion by MSH. Inhibitors of protein phosphatase 1 and protein phosphatase 2B (PP2B) do not affect pigment movement. Therefore, melanosome aggregation is mediated by PP2A. 相似文献
27.
RY Calne S Thiru P McMaster GN Craddock DJ White DJ Evans DC Dunn BD Pentlow K Rolles 《Canadian Metallurgical Quarterly》1998,9(9):1751-1756
A psychrotrophic yeast, Rhodotorula glutinis KUJ 2731, isolated from soil, effectively produced an extracellular endo-beta-glucanase (EC 3.2.1.4). The enzyme was monomeric, and the molecular mass was about 40,000 Da. The N-terminal amino acid sequence was H-Ser-Leu-Pro- Lys-Leu-Gly-Gly-Val-Asp-Leu-Ala-Gly-Leu-Asp-Ile-Gly-Lys-Asp-Lys-Asn-. alpha-Helix content was calculated to be about 32.6%. The isoelectric point was 8.57. The activation energy was 20.9 kJ/mol, which was much smaller than that of mesophilic enzymes. The enzyme was active at temperatures from 0 to 70 degrees C, with a highest initial velocity at 50 degrees C similar to other psychrotrophic enzymes. The enzyme was inhibited by Hg2+. The enzyme catalyzed hydrolysis of carboxymethyl cellulose with an apparent K(m) of 1.1% and Vmax of 556 mumol/min/mg. Products from the enzymatic hydrolysis of carboxymethyl cellulose by the enzyme were glucose, cellobiose, and cellotriose. The enzyme also catalyzed the transglycosylation of p-nitrophenyl-beta-cellotrioside to cellotetraose. 相似文献
28.
The medical management of Crohn's disease has changed in recent years, but the mainstay of treatment is still prednisone. A substantial fraction of steroid-treated patients are refractory to therapy and addition of azathioprine or methotrexate has a corticosteroid-sparing effect and increases duration of remission. Controlled ileal release budesonide (9 mg daily) induces clinical remission in 60-70% of patients with Crohn's ileitis or right-sided colitis, and continued budesonide treatment has a finite effect on the duration of remission. The efficacy of mesalazine in active Crohn's disease is limited and high doses are required (4000 mg/day). The role of mesalazine in Crohn's disease in remission is disputed, and there is no evidence of a corticosteroid-sparing effect. 相似文献
29.
Popa Iolanda V. Burlacu Alexandru Gavrilescu Otilia Dranga Mihaela Prelipcean Cristina Cijevschi Mihai Cătălina 《Neural computing & applications》2021,33(21):14133-14146
Neural Computing and Applications - Colonoscopy is the “gold” standard for evaluating disease activity in ulcerative colitis (UC). An important area of research is finding a... 相似文献
30.
C?t?lin Bu?neag Dana Piciu 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2012,16(10):1639-1655
The spectrum of a residuated lattice L is the set Spec(L) of all prime i-filters. It is well known that Spec(L) can be endowed with the spectral topology. The main scope of this paper is to introduce and study another topology on Spec(L),?the so called stable topology, which turns out to be coarser than the spectral one. With this and in view, we introduce the notions of pure i-filter for a residuated lattice and the notion of normal residuated lattice. So, we generalize to case of residuated lattice some results relative to MV-algebras (Belluce and Sessa in Quaest Math 23:269–277, 2000; Cavaccini et?al. in Math Japonica 45(2):303–310, 1997) or BL-algebras (Eslami and Haghani in Kybernetika 45:491–506, 2009; Leustean in Central Eur J Math 1(3): 382–397, 2003; Turunen and Sessa in Mult-Valued Log 6(1–2):229–249, 2001). 相似文献