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991.
J Sandoval J Gaspar T Pulido E Bautista ML Martínez-Guerra M Zeballos A Palomar A Gómez 《Canadian Metallurgical Quarterly》1998,32(2):297-304
Endothelial cell cultures were established from several wild African mammalian species. Long-term cultures were established from three ruminants, stable antelope (Hippotragus niger), buffalo (Syncerus caffer), and eland (Tragelaphus oryx), and from an omnivore, the bushpig (Potamochoerus porcus). Cowdria ruminanntium was isolated from plasma of clinically affected animals in these four cell lines and in bovine endothelial cells used routinely for C. ruminantium propagation. Nineteen different strains of C. ruminantium from Africa and the Caribbean region were grown and maintained in these cell lines and their growth was comparable with growth in the bovine endothelial cells. The role of sable antelope, eland, and bushpigs in the epidemiology of heartwater is unknown. However, these results extend the number of cell lines that can be used to isolate and grow C. ruminantium. 相似文献
992.
M Becares Lozano V Chimpén Ruiz JA Martín Oterino A Sánchez Rodríguez J de Portugal Alvarez 《Canadian Metallurgical Quarterly》1997,14(9):465-466
Enterococcal endocarditis accounts for 10% of all bacterial endocardits. The infection progresses in a subacute way and when localized on the aortic valve it has a very poor prognosis since the valve is usually destroyed being death the fatal outcome. We report a case of a patient with infective endocarditis resulting from the implantion of the Enterococcus on the native aortic valve. Nor visk factors or an apparent main gate could be found. The patient was hospitalized after several months of a non especific febrile syndrome. The literature is reviewed. Diagnostic tests and clinical signs are discussed making emphasis on the refractoriness to chemotherapy. 相似文献
993.
A Hernándiz Martínez V Pallarés Carratalá J Cosín Aguilar F Andrés Conejos C Capdevila Carbonell M Portolés Sanz 《Canadian Metallurgical Quarterly》1997,50(9):650-657
INTRODUCTION AND OBJECTIVES: Myocardial ATP is produced mainly by fatty acid oxidation, a process in which the fatty acid metabolite carrier carnitine is needed to carry the metabolites into the mitochondria. Cardiac ischemia is associated with carnitine depletion. Our objective was to study the functional effect of L-carnitine on myocardium stunned by very brief, repeated ischemias, and to examine its actions in the recovery period. METHODS: The two series studied were the control series (7 dogs) and the carnitine series (7 dogs). L-carnitine was administered to the carnitine series at doses of 250 mg/kg/day starting 7 days before the ischemic protocol and continuing during the follow-up period (10 and 15 days). The ischemic protocol consisted of 20 anterior descending coronary artery occlusions lasting 2 min and with 3 min of reperfusion between occlusions. Global and regional cardiac function parameters were recorded daily. RESULTS: No differences in the global functional (haemodynamic) or ECG of the two series were found, but there were differences in regional myocardial function. The control series segment shortening fraction fell to dyskinesis values during the occlusion periods, then recovered during reperfusions. The segment shortening fraction worsened during the stunning period, reaching its maximal impairment on the 5th day, after which it returned to basal values on the 15th day. The carnitine series showed the same performance in the occlusion/reperfusion period. However, during the stunning period the segment shortening fraction recovered and reached values close to the basal ones maintained them during the follow-up period. CONCLUSIONS: L-carnitine induces an almost immediate recovery of myocardial contractility, when it has been affected by very brief, repeated coronary occlusions. It limits the myocardial stunning apparition. 相似文献
994.
J Aristu J Rebollo R Martínez-Monge JM Aramendía JC Viera I Azinovic J Herreros A Brugarolas 《Canadian Metallurgical Quarterly》1997,20(3):276-281
The relation between diet and female colorectal cancer was analyzed in a prospective study of 14,727 women aged 34-65 years, who were enrolled at mammographic screening clinics in New York and Florida from 1985 to 1991. They were followed through the end of 1994 (average 7.1 yrs) by a combination of direct contact through mail and telephone and record linkages with regional tumor registries, resulting in 100 incident cases of colorectal cancer. There was no overall positive or inverse association of colorectal cancer risk with intakes of total calories, total or subclasses of fat, carbohydrate, or dietary fiber, whereas there was an inverse association with total protein. Among major food groups, there was a progressive decline in risk of colorectal cancer with increasing intake of fish and shellfish (relative risk for 4th vs. 1st quartile = 0.49, 95% confidence interval = 0.27-0.89). A similar inverse association was also observed for consumption of dairy products, and this association was explained mainly by calcium, not by other nutrients, such as fat or protein. The results of the present study indicated that certain dietary components of fish or dairy products may protect against colorectal cancer, whereas the relations with red meat or total fat remained unclear. 相似文献
995.
EE Stashenko MC Ferreira LG Sequeda JR Martínez JW Wong 《Canadian Metallurgical Quarterly》1997,779(1-2):360-369
High-resolution gas chromatography (HRGC) with electron-capture detection (ECD), nitrogen-phosphorus detection (NPD), flame ionization detection (FID) or with mass spectrometry-selected ion monitoring (MS-SIM) was used in the analysis of volatile carbonyl compounds. Eighteen carbonyl compounds that are typically produced during lipid peroxidation were derivatized quantitatively with pentafluorophenylhydrazine (PFPH) at room temperature, to afford their corresponding water-insoluble hydrazones. These derivatives were extracted into non-polar phases by means of either liquid-liquid extraction (LLE) (hexane) or solid-phase extraction (SPE) on 3 ml C18 octadecyl-bonded phase cartridges. Detection limits of 10(-14) and 10(-12) mol/ml per aldehyde were achieved with the ECD and MS-SIM systems, respectively. The effects of extraction conditions on sensitivity and recovery were determined by performing parallel HRGC-ECD and HRGC-MS-SIM analyses of pentafluorophenylhydrazones of the eighteen compounds under study. Recoveries of 51.4-78.9 +/- 1.2-4.5 and 80.9-98.3 +/- 1.0-3.5% were obtained with LLE and SPE, respectively. The method was applied to the analysis of the volatile carbonyl compounds in various heated vegetable oils (corn, palm or sunflower) and to the analysis of volatile aldehydes in human urine. 相似文献
996.
MV Aguilar FJ Jiménez-Jiménez JA Molina I Meseguer CJ Mateos-Vega MJ González-Mu?oz F de Bustos C Gómez-Escalonilla M Ort-Pareja M Zurdo MC Martínez-Para 《Canadian Metallurgical Quarterly》1998,105(10-12):1245-1251
We compared CSF and serum levels of selenium and chromium, measured by atomic absorption spectrophotometry, in 28 patients with Parkinson's disease (PD) and 43 matched controls. The CSF and serum levels of these trace metals did not differ significantly between PD patients and controls. CSF selenium and chromium levels were not correlated with age, age at onset, duration of the disease, scores of the Unified Parkinson Disease Rating Scale of the Hoehn and Yahr staging in the PD group. Although antiparkinsonian therapy did not influence significantly the CSF levels of selenium, PD patients not treated with levodopa had significantly higher CSF selenium levels than controls (p < 0.01). It is possible that increased CSF selenium levels could indicate an attempt of protection against oxidative stress. The normality of CSF and serum chromium levels suggest that these values are not related with the risk for PD. 相似文献
997.
Märt Kolnes Arvo Mere Jakob Kübarsepp Mart Viljus Birgit Maaten Marek Tarraste 《粉末冶金学》2018,61(3):197-209
From the outlook of healthcare, economic importance and supply risk, utilisation of raw materials like tungsten, cobalt and nickel should be reduced or replaced with other metals. Nontoxic titanium carbide and iron are the top-of-the-line solution for displacing these materials. Our focus was on conventionally fabricated titanium carbide-based cermets with a chromium ferritic steel binder. To study microstructural evolution, specimens were sintered at different temperatures (600–1500°C). We used a scanning electron microscopy, X-ray diffraction and differential scanning calorimetry to analyse the microstructure and phase formation of the cermets. Our results showed that during the solid and liquid phase sintering of the TiC–FeCr cermet, chromium ferrous complex carbides M7C3 are formed and as a result, chromium content in the binder phase is decreased. Alloying TiC–FeCr cermets with strong carbide formers improves the structural homogeneity of the cermets. Also, mechanical characteristics (hardness, fracture toughness) were evaluated. 相似文献
998.
Agustín Eduardo Bravo Bénard David Martínez Hernández José Gonzalo González Reyes Armando Ortiz Prado Rafael Schouwenaars Franssens 《Metallurgical and Materials Transactions A》2014,45(2):555-562
The use of Mg as an alloying element in copper alloys has largely been overlooked in scientific literature and technological applications. Its supposed tribological compatibility with iron makes it an interesting option to replace Pb in tribological alloys. This work describes the casting process of high-quality thin slabs of Cu-Mg-Sn alloys with different compositions by means of conventional methods. The resulting phases were analyzed using X-ray diffraction, scanning electron microscopy, optical microscopy, and energy dispersive X-ray spectroscopy techniques. Typical dendritic α-Cu, eutectic Cu2Mg(Sn) and eutectoid non-equilibrium microstructures were found. Tensile tests and Vickers microhardness show the excellent hardening capability of Mg as compared to other copper alloys in the as-cast condition. For some of the slabs and compositions, cold rolling reductions of over 95 pct have been easily achieved. Other compositions and slabs have failed during the deformation process. Failure analysis after cold rolling reveals that one cause for brittleness is the presence of casting defects such as microshrinkage and inclusions, which can be eliminated. However, for high Mg contents, a high volume fraction of the intermetallic phase provides a contiguous path for crack propagation through the connected interdendritic regions. 相似文献
999.
Sadott Pacheco Martín Medina Félix Valencia Josefina Tapia 《Canadian Metallurgical Quarterly》2006,132(3):342-349
This paper presents a process for the removal of inorganic mercury from aqueous solutions using alumina nanoparticles, which were prepared by the sol-gel method. Different amounts of mercury were added to the particles until a critical concentration was achieved, thus inducing the alumina sol flocculation. Particle growth was monitored during the process using dynamic light scattering. The amount of metal ion adsorbed on the surface of the alumina sols was determined by atomic absorption spectroscopy. Initial mercury concentrations ranging between 50 and 100 ppm decreased to below 1 ppb in a short time. 相似文献
1000.
Moliner Carolina; Martínez-Tur Vicente; Peiró José M.; Ramos José; Cropanzano Russell 《Canadian Metallurgical Quarterly》2005,12(2):99
Relationships between organizational justice and well-being are traditionally investigated at the individual level. This article extends previous efforts by testing such relationships at the work-unit level. Three corridors of influence were examined. First, the level (work units' average scores) of justice is related to the level of burnout. Second, justice climate strength (level of agreement among work-unit members) moderates the predictability of the level of burnout. Third, justice strength is related to burnout strength. The authors interviewed 324 contact employees from 108 work units in 59 service organizations. Findings showed the predominance of interactional justice over distributive and procedural justice in all 3 corridors. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献