227 research outputs found

    A theoretical investigation of orientation relationships and transformation strains in steels

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    The identification of orientation relationships (ORs) plays a crucial role in the understanding of solid phase transformations. In steels, the most common models of ORs are the ones by Nishiyama–Wassermann (NW) and Kurdjumov– Sachs (KS). The defining feature of these and other OR models is the matching of directions and planes in the parent face-centred cubic gamma phase to ones in the product body-centred cubic/tetragonal alpha\alpha' phase. In this article a novel method that identifies transformation strains with ORs is introduced and used to develop a new strain-based approach to phase-transformation models in steels. Using this approach, it is shown that the transformation strains that leave a close-packed plane in the gamma phase and a close-packed direction within that plane unrotated are precisely those giving rise to the NW and KS ORs when a cubic product phase is considered. Further, it is outlined how, by choosing different pairs of unrotated planes and directions, other common ORs such as the ones by Pitsch and Greninger–Troiano can be derived. One of the advantages of our approach is that it leads to a natural generalization of the NW, KS and other ORs for different ratios of tetragonality r of the product body-centred tetragonal alpha' phase. These generalized ORs predict a sharpening of the transformation textures with increasing tetragonality and are thus in qualitative agreement with experiments on steels with varying alloy concentratio

    Vascular effects and safety of dalcetrapib in patients with or at risk of coronary heart disease: the dal-VESSEL randomized clinical trial

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    Aims High-density lipoprotein cholesterol (HDL-C) is inversely associated with cardiovascular (CV) events and thus an attractive therapeutic target. However, in spite of marked elevations in HDL-C, the first cholesterol transport protein (CETP) inhibitor torcetrapib raised blood pressure (BP), impaired endothelial function, and increased CV mortality and morbidity. Dalcetrapib is a novel molecule acting on CETP with a different chemical structure to torcetrapib. As HDL stimulates nitric oxide (NO), suppresses inflammation, and exerts protective CV effects, we investigated the effects of dalcetrapib on endothelial function, blood pressure, inflammatory markers, and lipids in patients with, or at risk of, coronary heart disease (CHD) in a double-blind randomized placebo-controlled trial (clinicaltrials.gov number NCT00655538). Methods and results Patients with target low-density lipoprotein cholesterol (LDL-C) levels received dalcetrapib 600 mg/day or placebo for 36 weeks on top of standard therapy (including statins). The primary outcome measures were the change from baseline of flow-mediated dilatation (%FMD) of the right brachial artery after 5 min of cuff occlusion at 12 weeks and the 24 h ambulatory blood pressure monitoring (ABPM) at week 4. Secondary outcomes included change from baseline in FMD after 36 weeks and the change in ABPM at 12 and 36 weeks, changes in HDL-C, LDL-C, triglycerides, CETP activity, as well as standard safety parameters. Four hundred seventy-six patients were randomized. Baseline FMD was 4.1 ± 2.2 and 4.0 ± 2.4% with placebo or dalcetrapib, respectively and did not change significantly from placebo after 12 and 36 weeks (P = 0.1764 and 0.9515, respectively). After 4, 24, and 36 weeks of treatment with dalcetrapib, CETP activity decreased by 51, 53, and 56% (placebo corrected, all P < 0.0001), while at weeks 4, 12, and 36 HDL-C increased by 25, 27, and 31% (placebo corrected, all P < 0.0001). Low-density lipoprotein cholesterol levels did not change. At baseline, ABPM was 125 ± 12/74 ± 8mmHg in the placebo and 128 ± 11/75 ± 7mmHg in the dalcetrapib group (P = 0.3372 and 0.1248, respectively, placebo-corrected change from baseline) and did not change for up to 36 weeks. Biomarkers of inflammation, oxidative stress, and coagulation did not change during follow-up except for Lp-PLA2 mass levels which increased by 17% (placebo corrected). Overall 7 patients given dalcetrapib and 8 patients given placebo experienced at least one pre-specified adjudicated event (11 events with dalcetrapib and 12 events with placebo). Conclusion The dal-VESSEL trial has established the tolerability and safety of CETP-inhibition with dalcetrapib in patients with or at risk of CHD. Dalcetrapib reduced CETP activity and increased HDL-C levels without affecting NO-dependent endothelial function, blood pressure, or markers of inflammation and oxidative stress. The dal-OUTCOMES trial (NCT00658515) will show whether dalcetrapib improves outcomes in spite of a lack of effect on endothelial functio

    Relationship of Serum Inflammatory Biomarkers With Plaque Inflammation Assessed by FDG PET/CT The dal-PLAQUE Study

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    ObjectivesThis study sought to longitudinally investigate the relationship between a broad spectrum of serum inflammatory biomarkers and plaque inflammation assessed by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT).BackgroundBoth plaque inflammation and serum biomarkers of inflammation are associated with atherothrombotic events; however, the relationship between them is unclear.MethodsWe conducted a post hoc analysis of the dal-PLAQUE (A Randomized Placebo-Controlled Study of the Effect of RO4607381 on Progression or Regression of Atherosclerotic Plaque in Patients With Coronary Heart Disease [CHD] Including Patients With Other CHD Risk Factors), a randomized, placebo-controlled study of dalcetrapib, a cholesteryl ester transfer protein inhibitor, in 130 patients with coronary heart disease, or coronary heart disease risk equivalents on stable lipid-lowering therapy. Baseline and change after 3-month follow-up in inflammatory biomarker levels and baseline and change after 3-month follow-up in aorta and carotid 18F-FDG PET/CT (mean maximum target-to-background ratio of the most diseased segment [TBRmds]) were analyzed.ResultsBaseline myeloperoxidase positively correlated with baseline carotid TBRmds (rho = 0.25, p = 0.02). This correlation remained at the 3-month follow-up and was independent of traditional cardiovascular disease risk factors. Baseline lipoprotein-associated phospholipase A2 mass correlated with aorta TBRmds (rho = 0.21, p = 0.03). However, this correlation disappeared at the 3-month follow-up and was not independent of cardiovascular disease risk factors. There was no association between change from baseline in myeloperoxidase or lipoprotein-associated phospholipase A2 mass and change from baseline in aorta and carotid TBRmds. Baseline and change from baseline in high sensitivity C-reactive protein, interleukin 6, soluble P-selectin, soluble E-selectin, soluble intracellular adhesion molecule 1, soluble vascular cell adhesion molecule 1, and matrix-metalloproteinase 3 and 9 did not correlate with baseline or change from baseline in carotid or aorta TBRmds.ConclusionsOur data show that, in patients with coronary heart disease or at high risk of coronary heart disease on stable lipid-lowering therapy, circulating myeloperoxidase levels are associated with carotid plaque inflammation. (A Randomized, Placebo-controlled Study of the Effect of RO4607381 on Progression or Regression of Atherosclerotic Plaque in Patients With Coronary Heart Disease [CHD] Including Patients With Other CHD Risk Factors [dal-PLAQUE]; NCT00655473

    Effects of dalcetrapib in patients with a recent acute coronary syndrome

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    In observational analyses, higher levels of high-density lipoprotein (HDL) cholesterol have been associated with a lower risk of coronary heart disease events. However, whether raising HDL cholesterol levels therapeutically reduces cardiovascular risk remains uncertain. Inhibition of cholesteryl ester transfer protein (CETP) raises HDL cholesterol levels and might therefore improve cardiovascular outcomes

    Does Vascular Calcification Accelerate Inflammation?: A Substudy of the dal-PLAQUE Trial.

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    BACKGROUND: Atherosclerosis is an inflammatory condition with calcification apparent late in the disease process. The extent and progression of coronary calcification predict cardiovascular events. Relatively little is known about noncoronary vascular calcification. OBJECTIVES: This study investigated noncoronary vascular calcification and its influence on changes in vascular inflammation. METHODS: A total of 130 participants in the dal-PLAQUE (Safety and efficacy of dalcetrapib on atherosclerotic disease using novel non-invasive multimodality imaging) study underwent fluorodeoxyglucose positron emission tomography/computed tomography at entry and at 6 months. Calcification of the ascending aorta, arch, carotid, and coronary arteries was quantified. Cardiovascular risk factors were related to arterial calcification. The influences of baseline calcification and drug therapy (dalcetrapib vs. placebo) on progression of calcification were determined. Finally, baseline calcification was related to changes in vascular inflammation. RESULTS: Age >65 years old was consistently associated with higher baseline calcium scores. Arch calcification trended to progress more in those with calcification at baseline (p = 0.055). There were no significant differences between progression of vascular calcification with dalcetrapib compared to that with placebo. Average carotid target-to-background ratio indexes declined over 6 months if carotid calcium was absent (single hottest slice [p = 0.037], mean of maximum target-to-background ratio [p = 0.010], and mean most diseased segment [p < 0.001]), but did not significantly change if calcification was present at baseline. CONCLUSIONS: Across multiple arterial regions, higher age is consistently associated with higher calcium scores. The presence of vascular calcification at baseline is associated with progressive calcification; in the carotid arteries, calcification appears to influence vascular inflammation. Dalcetrapib therapy did not affect vascular calcification.The study was supported by F. Hoffmann-La Roche Ltd, Basel, Switzerland. Some editorial assistance was provided by Prime Healthcare and was funded by F. Hoffmann-La Roche Ltd, Basel, Switzerland. Partial support is acknowledged from NIH/NHLBI R01 HL071021 (ZAF). We thank Elisabetta Damonte for helping with statistical analyses.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jacc.2015.10.05
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