An Analysis of 3D Simulation of SI Combustion with an Improved Version of the Kiva 3V Code: Numerical Formulation and Experimental Validation

The correct simulation of combustion process allows to better face several SI engines design problems, not only for innovative mixture formation concepts (stratified or ultra-lean charge), but for traditional homogeneous mixture as well. Even though many commercial codes are able to describe the complex 3-D non reacting fluid dynamics in ICE, the simulation of high turbulent flame propagation does not seem to be a completely solved problem yet. In this work a comparison between two different turbulent combustion models (a characteristic time based one by Abraham and Reitz [2, 15, 16] and a flamelet based one by Cant and AbuOrf [4, 20]) has been performed using KIVA-3V code to assess simulation reliability. Models predictive capabilities have been tested with reference to specific data acquired at the engine test bench of Tor Vergata Mechanical Engineering Department on a Fiat Punto 1242 cc 8 valves SI engine over a wide range of operating conditions. A generally good agreement has been observed between experimental and numerical results obtained by using both the combustion models. In addition it can be noticed that, thanks to a more physical description of the local turbulent flame characteristics, Cant model seems to exhibit more predicting reliability in the whole engine operating field

Deoxyribonucleic acid damage in human lymphocytes after percutaneous transluminal coronary angioplasty

AbstractObjectivesWe investigated the presence of oxidative deoxyribonucleic acid (DNA) damage in the peripheral lymphocytes of patients undergoing percutaneous transluminal coronary angioplasty (PTCA) by using the micronucleus test and comet assay, which are sensitive biomarkers of DNA damage.BackgroundAlthough it has recognized that ischemia-reperfusion can induce oxidative DNA damage, its occurrence in patients undergoing PTCA has not yet been demonstrated.MethodsThree groups of patients were enrolled: 30 patients with documented coronary heart disease who underwent elective PTCA (group I); 25 patients who underwent elective coronary angiography for diagnostic purpose (group II); and 27 healthy, age- and gender-matched subjects (group III). For each subject, the frequency of micronucleated binucleated (MNBN) cells, DNA single-strand breaks (SSBs), endonuclease III-sensitive sites, and sites sensitive to formamidopyrimidine glycosylase (FPG) were analyzed before and after diagnostic procedures.ResultsThe mean basal values of MNBN cells (p = 0.04), DNA-SSBs (p = 0.001), endonuclease III-sensitive sites (p = 0.002), and FPG sites (p < 0.0001) were significantly higher in groups I and II than in group III. A high significant increase of MNBN cell frequency was observed in group I after the PTCA procedure (11.0 ± 1.3 vs. 19.8 ± 1.6, p < 0.0001), whereas no significant difference was observed in group II (10.2 ± 1.3 vs. 12.9 ± 1.4, p = 0.18). A significant positive correlation was observed between the increase in the MNBN cell rate and total inflation time during PTCA (R = 0.549, p = 0.0017). The levels of DNA-SSBs (11.7 ± 1.4 vs. 26.5 ± 3.0, p = 0.0003) and FPG sites (13.8 ± 1.8 vs. 22.5 ± 2.4, p = 0.01) were also higher after PTCA.ConclusionsOur results provide evidence for oxidative DNA damage after PTCA, likely related to ischemia-reperfusion injury

Prothrombotic mutations, family history and the risk of thrombosis in postmenopausal women: implications for hormone replacement therapy

Objective Hormone replacement therapy (HRT) is acknowledged as the gold standard for the alleviation of climacteric vasomotor symptoms. Prothrombotic genetic variants have been suggested to increase thrombotic risk among HRT users. The aim of the study was to determine whether a positive family history may identify a genetic predisposition for thrombosis in women before prescribing HRT. Methods From January 2005 to May 2009, we consecutively enrolled 145 asymptomatic women (mean age 51.2+5.4 years) without previous episodes of venous and/or arterial thrombosis referred to our Genetics Research Unit before starting HRT. A detailed family history was reconstructed and we identified 48 women (33.1%) with a positive family history, defined as venous thromboembolism and/or stroke or heart attack, in first-degree relatives before 60 years for men and 65 years for women. A group of 121 women (mean age 54.0+9.1 years) with an episode of venous and/or arterial thrombosis was also included. Genetic screening for factor V Leiden, prothrombin G20210A and methylenetetrahydrofolate reductase C677T polymorphisms was performed. Results The frequency of factor V Leiden or prothrombin G20210A mutations was significantly higher both in asymptomatic women with a positive family history (16.7% vs. 2.1%, p?0.001) and in patients with thrombosis (12.4% vs. 2.1%; p?0.005) compared with asymptomatic women without a family history. Multivariate regression analysis showed a synergic effect between the presence of one prothrombotic mutation and family history on the risk of thrombosis (odds ratio 3.7, 95% confidence interval 1.9-7.2). Conclusions A positive family history of thrombosis is a sensitive indicator for selected genetic testing in high-risk women before starting HRT

Cytoplasmic cleavage of IMPA1 3' UTR is necessary for maintaining axon integrity

The 3′ untranslated regions (3′ UTRs) of messenger RNAs (mRNAs) are non-coding sequences involved in many aspects of mRNA metabolism, including intracellular localization and translation. Incorrect processing and delivery of mRNA cause severe developmental defects and have been implicated in many neurological disorders. Here, we use deep sequencing to show that in sympathetic neuron axons, the 3′ UTRs of many transcripts undergo cleavage, generating isoforms that express the coding sequence with a short 3′ UTR and stable 3′ UTR-derived fragments of unknown function. Cleavage of the long 3′ UTR of Inositol Monophosphatase 1 (IMPA1) mediated by a protein complex containing the endonuclease argonaute 2 (Ago2) generates a translatable isoform that is necessary for maintaining the integrity of sympathetic neuron axons. Thus, our study provides a mechanism of mRNA metabolism that simultaneously regulates local protein synthesis and generates an additional class of 3′ UTR-derived RNAs

Ferulated Poly(vinyl alcohol) based hydrogels

New graft copolymers were prepared by reaction of poly (vinyl alcohol) (PVA) with mono-imidazolide or bis-imidazolide derivatives of ferulic acid (FA) with the formation of ester bonds. The obtained graft copolymers, thanks to the crosslinking capability of FA, formed in water strong gels as verified by rheological analyses. The resulting hydrogels were characterized to evaluate their applicability as wound dressing. In this perspective, their capability to absorb and retain a large amount of fluid without dissolving was verified by swelling kinetics and Moisture Vapour Transmission Rate measurements. Their stability towards mechanical solicitations was assessed by quantifying elasticity, compliance, stress-relaxation, and adhesivity properties. The analyses pointed out that hydrogel PVA-FA2-3 obtained by feruloylation of PVA with bis-imidazole derivative of ferulic acid using an acylation agent/polymer molar ratio 0.03/1 resulted the best candidate for the foreseen application