386 research outputs found

    Mode of occurrence of plagioclase-rich segregation in the Horoman peridotite

    Get PDF

    Impact of incomplete percutaneous revascularization in patients With multivessel coronary artery disease: a systematic review and meta-analysis

    Get PDF
    Background: Up to half of patients undergoing percutaneous coronary intervention have multivessel coronary artery disease (MVD) with conflicting data regarding optimal revascularization strategy in such patients. This paper assesses the evidence for complete revascularization (CR) versus incomplete revascularization in patients undergoing percutaneous coronary intervention, and its prognostic impact using meta‐analysis. Methods and Results: A search of PubMed, EMBASE, MEDLINE, Current Contents Connect, Google Scholar, Cochrane library, Science Direct, and Web of Science was conducted to identify the association of CR in patients with multivessel coronary artery disease undergoing percutaneous coronary intervention with major adverse cardiac events and mortality. Random‐effects meta‐analysis was used to estimate the odds of adverse outcomes. Meta‐regression analysis was conducted to assess the relationship with continuous variables and outcomes. Thirty‐eight publications that included 156 240 patients were identified. Odds of death (OR 0.69, 95% CI 0.61‐0.78), repeat revascularization (OR 0.60, 95% CI 0.45‐0.80), myocardial infarction (OR 0.64, 95% CI 0.50‐0.81), and major adverse cardiac events (OR 0.63, 95% CI 0.50‐0.79) were significantly lower in the patients who underwent CR. These outcomes were unchanged on subgroup analysis regardless of the definition of CR. Similar findings were recorded when CR was studied in the chronic total occlusion (CTO) subgroup (OR 0.65, 95% CI 0.53‐0.80). A meta‐regression analysis revealed a negative relationship between the OR for mortality and the percentage of CR. Conclusion: CR is associated with reduced risk of mortality and major adverse cardiac events, irrespective of whether an anatomical or a score‐based definition of incomplete revascularization is used, and this magnitude of risk relates to degree of CR. These results have important implications for the interventional management of patients with multivessel coronary artery disease

    マントル溶融過程の多様性: 特にメルト移動の場におけるメルト/マントル相互反応の重要性について

    Get PDF
    取得学位:博士(理学),学位授与番号:博甲第255号,学位授与年月日:平成10年3月25日,学位授与年:199

    Rheology of hexagonal close-packed(hcp) iron

    Get PDF
    The viscosity of hexagonal close-packed (hcp) Fe is a fundamental property controlling the dynamics of the Earth’s inner core. We studied the rheology of hcp-Fe using high-pressure and -temperature deformation experiments with in situ stress and strain measurements. Experiments were conducted using D111-type and deformation-DIA apparatuses at pressures of 16.3–22.6 GPa, temperatures of 423–923 K, and uniaxial strain rates of 1.52 × 10−6 to 8.81 × 10−5 s−1 in conjunction with synchrotron radiation. Experimental results showed that power-law dislocation creep with a stress exponent of n = 4.0 ± 0.3, activation energy of E* = 240 ± 20 kJ/mol, and activation volume of V* = 1.4 ± 0.2 cm3/mol is dominant deformation mechanism at >∼800 K, whereas a mechanism with power-law breakdown prevails at lower temperatures. An extrapolation of the power-law dislocation creep flow law based on homologous temperature scaling suggests the viscosity of hcp-Fe under inner core conditions is ≥∼1019 Pa s. If this power-law dislocation creep mechanism is assumed to be the dominant mechanism in the Earth’s inner core, the equatorial growth or translation mode mechanism may be the dominant geodynamical mechanism causing the observed inner core structure

    Impact of transport pathways on the time from symptom onset of ST-segment elevation myocardial infarction to door of coronary intervention facility

    Get PDF
    AbstractBackgroundReducing total ischemic time is important in achieving better outcome in ST-segment elevation myocardial infarction (STEMI). Although the onset-to-door (OTD) time accounts for a large portion of the total ischemic time, factors affecting prolongation of the OTD time are not established.PurposeThe purpose of this study was to determine the impact of transport pathways on OTD time in patients with STEMI.Methods and subjectsWe retrospectively studied 416 STEMI patients who were divided into 4 groups according to their transport pathways; Group 1 (n=41): self-transportation to percutaneous coronary intervention (PCI) facility; Group 2 (n=215): emergency medical service (EMS) transportation to PCI facility; Group 3 (n=103): self-transportation to non-PCI facility; and Group 4 (n=57): EMS transportation to non-PCI facility. OTD time was compared among the 4 groups.Essential resultsMedian OTD time for all groups combined was 113 (63–228.8)min [Group 1, 145 (70–256.5); Group 2, 71 (49–108); Group 3, 260 (142–433); and Group 4, 184 (130–256)min]. OTD time for EMS users (Groups 2 and 4) was 138min shorter than non-EMS users (Groups 1 and 3). Inter-hospital transportation (Groups 3 and 4) prolonged OTD by a median of 132min compared with direct transportation to PCI facility (Groups 1 and 2). Older age, history of myocardial infarction, prior PCI, shock at onset, high Killip classification, and high GRACE Risk Score were significantly more frequent in EMS users.Principal conclusionsSelf-transportation without EMS and inter-hospital transportation were significant factors causing prolongation of the OTD time. Approximately 35% of STEMI patients did not use EMS and 21% of patients were transported to non-PCI facilities even though they called EMS. Awareness in the community as well as among medical professionals to reduce total ischemic time of STEMI is necessary; this involves educating the general public and EMS crews

    First Principles NMR Study of Fluorapatite under Pressure

    Full text link
    NMR is the technique of election to probe the local properties of materials. Herein we present the results of density functional theory (DFT) \textit{ab initio} calculations of the NMR parameters for fluorapatite (FAp), a calcium orthophosphate mineral belonging to the apatite family, by using the GIPAW method [Pickard and Mauri, 2001]. Understanding the local effects of pressure on apatites is particularly relevant because of their important role in many solid state and biomedical applications. Apatites are open structures, which can undergo complex anisotropic deformations, and the response of NMR can elucidate the microscopic changes induced by an applied pressure. The computed NMR parameters proved to be in good agreement with the available experimental data. The structural evaluation of the material behavior under hydrostatic pressure (from --5 to +100 kbar) indicated a shrinkage of the diameter of the apatitic channel, and a strong correlation between NMR shielding and pressure, proving the sensitivity of this technique to even small changes in the chemical environment around the nuclei. This theoretical approach allows the exploration of all the different nuclei composing the material, thus providing a very useful guidance in the interpretation of experimental results, particularly valuable for the more challenging nuclei such as 43^{43}Ca and 17^{17}O.Comment: 8 pages, 2 figures, 3 table

    On the relative importance of thermal and chemical buoyancy in regular and impact-induced melting in a Mars-like planet

    Get PDF
    We ran several series of two-dimensional numerical mantle convection simulations representing in idealized form the thermochemical evolution of a Mars-like planet. In order to study the importance of compositional buoyancy of melting mantle, the models were set up in pairs of one including all thermal and compositional contributions to buoyancy and one accounting only for the thermal contributions. In several of the model pairs, single large impacts were introduced as causes of additional strong local anomalies, and their evolution in the framework of the convecting mantle was tracked. The models confirm that the additional buoyancy provided by the depletion of the mantle by regular melting can establish a global stable stratification of the convecting mantle and throttle crust production. Furthermore, the compositional buoyancy is essential in the stabilization and preservation of local compositional anomalies directly beneath the lithosphere and offers a possible explanation for the existence of distinct, long-lived reservoirs in the martian mantle. The detection of such anomalies by geophysical means is probably difficult, however; they are expected to be detected by gravimetry rather than by seismic or heat flow measurements. The results further suggest that the crustal thickness can be locally overestimated by up to ~20 km if impact-induced density anomalies in the mantle are neglected.Comment: 29 pages, 10 figure

    Impact of incomplete percutaneous revascularization in patients with multi-vessel coronary artery disease: a systematic review and meta-analysis

    Get PDF
    Background Up to half of patients undergoing percutaneous coronary intervention have multivessel coronary artery disease (MVD) with conflicting data regarding optimal revascularization strategy in such patients. This paper assesses the evidence for complete revascularization (CR) versus incomplete revascularization in patients undergoing percutaneous coronary intervention, and its prognostic impact using meta‐analysis. Methods and Results A search of PubMed, EMBASE, MEDLINE, Current Contents Connect, Google Scholar, Cochrane library, Science Direct, and Web of Science was conducted to identify the association of CR in patients with multivessel coronary artery disease undergoing percutaneous coronary intervention with major adverse cardiac events and mortality. Random‐effects meta‐analysis was used to estimate the odds of adverse outcomes. Meta‐regression analysis was conducted to assess the relationship with continuous variables and outcomes. Thirty‐eight publications that included 156 240 patients were identified. Odds of death (OR 0.69, 95% CI 0.61‐0.78), repeat revascularization (OR 0.60, 95% CI 0.45‐0.80), myocardial infarction (OR 0.64, 95% CI 0.50‐0.81), and major adverse cardiac events (OR 0.63, 95% CI 0.50‐0.79) were significantly lower in the patients who underwent CR. These outcomes were unchanged on subgroup analysis regardless of the definition of CR. Similar findings were recorded when CR was studied in the chronic total occlusion (CTO) subgroup (OR 0.65, 95% CI 0.53‐0.80). A meta‐regression analysis revealed a negative relationship between the OR for mortality and the percentage of CR. Conclusion CR is associated with reduced risk of mortality and major adverse cardiac events, irrespective of whether an anatomical or a score‐based definition of incomplete revascularization is used, and this magnitude of risk relates to degree of CR. These results have important implications for the interventional management of patients with multivessel coronary artery disease
    corecore