Quantum mechanic study of high molecular mass compounds in combustion conditions

Journal ArticleExperimental studies on soot formation show interesting trends that can only be explained by a polymerization pathway. These experimental findings are reviewed and ab initio calculations are used to evaluate possible mechanistic pathways. A sequence of chemical reactions between aromatic compounds and compounds containing conjugated double bonds was studied in detail. The reactions analyzed represent a first possible propagation step of a sequence that can be easily repeated for the formation of high molecular mass compounds. The distinguishing features of the proposed model lie in the chemical specificity of the routes proposed. The aromatic radical attacks the double bond of five-membered ring PAH giving addition reactions. This is allowed by specific compounds that are exceptional monomers as they form resonantly stabilized radical intermediates, relieving part of the large strain in the five-membered rings by linear polymer formation

Determinants of fibrinogen in an Italian population suffering from claudication. Lower fibrinogen in the south compared to middle and north of Italy. The ADEP Group.

Prospective studies have shown that high plasma levels of fibrinogen are independently associated with the risk of cardiovascular complications. In patients suffering from peripheral vascular disease (PVD) fibrinogen has been shown to be an independent predictor of cardiovascular disease but its determinants have never been examined in this clinical setting. DESIGN AND METHODS: Fibrinogen levels were related to clinical and laboratory variables in 2,111 patients suffering from PVD. We also analyzed whether there was a regional distribution of risk factors. RESULTS: The median values of fibrinogen was 312 mg/dL. The clinical variables examined did not differentiate patients with elevated or normal fibrinogen levels. In particular, patients with ankle/arm pressure ratio < 0.8 did not show a higher prevalence of fibrinogen > 312 mg/dL. Conversely, white blood cell (WBC) count and serum cholesterol levels were significantly associated with high fibrinogen levels (p < 0.0001). Multiple logistic regression analysis demonstrated that areas of Italy were differently associated with high plasma fibrinogen levels (p < 0.03): subjects in the north and middle of Italy having significantly higher values of fibrinogen than subjects in the south of Italy (p < 0.01). A similar regional distribution was observed for WBC count and serum cholesterol levels. INTERPRETATION AND CONCLUSIONS: The regional distribution of risk factors raises the question as to whether the already reported large variability of cardiovascular events so in PVD may be attributed to a non homogeneous distribution of risk factors

Identification of pathways for polyaromatic growth using molecular dynamics

Journal ArticleReaction pathways for polyaromatic growth in combustion environments are explored theoretically using molecular dynamic techniques. The reaction systems considered include cyclization reactions that involve H atom migration. Specifically we examine the absorption of acetylene on an aromatic ring radical. The Parallel Replica method for accelerating Molecular Dynamics calculations is used to screen reaction pathways. The information obtained through the use of Molecular Dynamics runs are then analyzed with quantum chemical methods and thermodynamic data for the key compounds

Enhancing the Toolbox of Fixed Income Active Portfolio Management

AbstractMany central banks adopt an active investment style for reserve management. This paper discusses various possible enhancements to active management tools and processes to generate extra returns in an increasingly challenging environment. The proposed framework is based on an affine model, which includes macroeconomic and market sentiment indicators among the explanatory variables. Using estimates of expected excess returns drawn from the model, an operational indicator produces input highlighting the portfolio's exposure to duration risk. This indicator is incorporated within a broader framework, in which a scorecard considers a range of qualitative elements, including consensus figures on macroeconomic data, monetary policy and interest rates. These elements are then combined with the model output to produce a comprehensive indication with respect to portfolio deviation from the benchmark. It should be noted that the approach presented in this paper is experimental; it has not yet been used in an active portfolio. Finally, consideration is given to the governance of the central bank investment process in order to assess how the proposed enhancements could strengthen the decision-making process. The analysis suggests that the scorecard with model-based input may address some weaknesses inherent in tactical decision- making.The views expressed herein are solely our own and do not necessarily reflect those of the Bank of Italy or the European System of Central Banks

Spaces of Memory

In the last decade, museums, memorials and monuments have become the battlefield for competing and conflicting visions of the past and the hegemonic or counter memories of the so-called “difficult heritage” or “traumatic heritage”. Far from being mere spaces of musealization that freeze and fix dominant narratives of the past, spaces of memory are increasingly turning into sites of negotiations and reconfigurations of meaning in which social and political identities are debated, strengthened, or weakened in reference to the traumatic experiences of the past which they “represent”. Yet, what does it mean to spatially represent a (traumatic) memory, and what is a space of memory? In expanding and, simultaneously, problematizing Pierre Nora’s (Nora 1996) category of lieu de mémoire, the way we think of spaces of memory aims at an in-depth examination of the peculiar yet specific ways of re-thinking the nexus between space and memory: how do we elaborate, activate, and make visible spaces for memory? This question points to the dynamic construction that underlines the production and connection of spatiality and memory, as well as to the coexistence of a plurality of meanings and experiences that characterize spaces of memory

Extra virgin olive oil use is associated with improved post-prandial blood glucose and LDL cholesterol in healthy subjects

Extra virgin olive oil (EVOO) is a key component of the Mediterranean diet and seems to account for the protective effect against cardiovascular disease. However, the underlying mechanism is still elusive

Radiolabeled native low-density lipoprotein injected into patients with carotid stenosis accumulates in macrophages of atherosclerotic plaque

BACKGROUND: Accumulation of LDL within the arterial wall appears to play a crucial role in the initiation and progression of . The dynamic sequence of this event has not been fully elucidated in humans. METHODS AND RESULTS: In 7 with previous transient ischemic attack or stroke and critical (>70%) , autologous [(125)I]-labeled LDL or [(125)I]-labeled human serum albumin were 24 to 72 hours before endarterectomy. specimens obtained at endarterectomy were analyzed by autoradiography and immunohistochemistry. Autoradiographic study showed that LDL was localized prevalently in the foam cells of plaques, whereas the accumulation in the lipid core was negligible. Immunohistochemistry revealed that foam cells that had accumulated LDL were mostly CD68 positive, whereas a small number were alpha-actin positive. No accumulation of the radiotracer was detected in plaques after injection of human serum albumin. In 3 treated for 4 weeks with vitamin E (900 mg/d), an almost complete suppression of LDL uptake by was observed. CONCLUSIONS: This study shows that circulating LDL rapidly in human . The prevalent accumulation of LDL by provides strong support to the hypothesis that these cells play a crucial role in the pathogenesis of atherosclerosis