233 research outputs found

    Lagrangian wall shear stress structures and near-wall transport in high-Schmidt-number aneurysmal flows

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    The wall shear stress (WSS) vector field provides a signature for near-wall convective transport, and can be scaled to obtain a first-order approximation of the near-wall fluid velocity. The near-wall flow field governs mass transfer problems in convection-dominated open flows with high Schmidt number, in which case a flux at the wall will lead to a thin concentration boundary layer. Such near-wall transport is of particular interest in cardiovascular flows whereby haemodynamics can initiate and progress biological events at the vessel wall. In this study we consider mass transfer processes in pulsatile blood flow of abdominal aortic aneurysms resulting from complex WSS patterns. Specifically, the Lagrangian surface transport of a species released at the vessel wall was advected in forward and backward time based on the near-wall velocity field. Exposure time and residence time measures were defined to quantify accumulation of trajectories, as well as the time required to escape the near-wall domain. The effect of diffusion and normal velocity was investigated. The trajectories induced by the WSS vector field were observed to form attracting and repelling coherent structures that delineated species distribution inside the boundary layer consistent with exposure and residence time measures. The results indicate that Lagrangian WSS structures can provide a template for near-wall transport.</jats:p

    Alcohol and cigarette consumption predict mortality in patients with head and neck cancer: A pooled analysis within the International Head and Neck Cancer Epidemiology (INHANCE) Consortium

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    Background: This study evaluated whether demographics, pre-diagnosis lifestyle habits and clinical data are associated with the overall survival (OS) and head and neck cancer (HNC)-specific survival in patients with HNC. Patients and methods: We conducted a pooled analysis, including 4759 HNC patients from five studies within the International Head and Neck Cancer Epidemiology (INHANCE) Consortium. Cox proportional hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) were estimated including terms reported significantly associated with the survival in the univariate analysis. Results: Five-year OS was 51.4% for all HNC sites combined: 50.3% for oral cavity, 41.1% for oropharynx, 35.0% for hypopharynx and 63.9% for larynx. When we considered HNC-specific survival, 5-year survival rates were 57.4% for all HNC combined: 54.6% for oral cavity, 45.4% for oropharynx, 37.1% for hypopharynx and 72.3% for larynx. Older ages at diagnosis and advanced tumour staging were unfavourable predictors of OS and HNC-specific survival. In laryngeal cancer, low educational level was an unfavourable prognostic factor for OS (HR=2.54, 95% CI 1.01-6.38, for high school or lower versus college graduate), and status and intensity of alcohol drinking were prognostic factors both of the OS (current drinkers HR=1.73, 95% CI 1.16-2.58) and HNC-specific survival (current drinkers HR=2.11, 95% CI 1.22-3.66). In oropharyngeal cancer, smoking status was an independent prognostic factors for OS. Smoking intensity ( &gt; 20 cigarettes/day HR=1.41, 95% CI 1.03-1.92) was also an independent prognostic factor for OS in patients with cancer of the oral cavity. Conclusions: OS and HNC-specific survival differ among HNC sites. Pre-diagnosis cigarette smoking is a prognostic factor of the OS for patients with cancer of the oral cavity and oropharynx, whereas pre-diagnosis alcohol drinking is a prognostic factor of OS and HNC-specific survival for patients with cancer of the larynx. Low educational level is an unfavourable prognostic factor for OS in laryngeal cancer patients

    Schizosaccharomyces selective differential media

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    This study discusses the optimisation of a selectiv e and differential medium which would facilitate the isolation of Schizosaccharomyces (a genus with a low incidence compared to other microorganisms) to select individuals from this genus for industrial purposes, especially in light of the recent approval of the use of yeasts from this genus in the wine industry by the International Organisation of Vine and Wine, or to detect the presence of such yeasts, for those many authors who consider them food spoilers. To this end, we studied various selective differential agents based on the main thephysiological characteristics of this species, such as its high resistance to high concentrations of sugar, sulfur dioxide, sorbic acid, benzoic acid, acetic acid or malo ethanolic fermentation. This selective medium is based on the resistance of the genus to the antibiotic actidione and its high resistance to inhibitory agents such as benzoic acid compared to possible microorganisms which can give rise to false positive results. Malic acid was used as a differential fact or due to the ability of this genus to metabolise it to ethanol, which allows detecting of the degradation of this compound. Lastly, the medium was successfully used to isolate strains of Schizosaccharomyces pombe from honey

    Polymorphisms in metabolic genes, their combination and interaction with tobacco smoke and alcohol consumption and risk of gastric cancer: a case-control study in an Italian population

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    Background: The distribution and the potential gene-gene and gene-environment interaction of selected metabolic genetic polymorphisms was investigated in relation to gastric cancer risk in an Italian population. Methods: One hundred and seven cases and 254 hospital controls, matched by age and gender, were genotyped for CYP1A1, CYP2E1, mEH, GSTM1, GSTT1, NAT2 and SULT1A1 polymorphisms. Haplotype analysis was performed for EPHX1 exons 3 and 4, as well as CYP2E1 RsaI (*5 alleles) and CYP2E1 DraI (*5A or *6 alleles). The effect modification by alcohol and cigarette smoking was tested with the heterogeneity test, while the attributable proportion (AP) was used to measure the biological interaction from the gene-gene interaction analysis. Results: Gastric cancer risk was found to be associated with the inheritance of GSTT1 null genotype (OR = 2.10, 95%CI: 1.27-3.44) and the SULT1A1 His/His genotype (OR = 2.46, 95%CI: 1.03-5.90). No differences were observed for the haplotype distributions among cases and controls. For the first time an increased risk was detected among individuals carrying the *6 variant allele of CYP2E1 if ever-drinkers (OR = 3.70; 95%CI: 1.45-9.37) with respect to never-drinkers (OR = 0.18; 95% CI: 0.22-1.46) (p value of heterogeneity among the two estimates = 0.001). Similarly, the effect of SULT1A1 variant genotype resulted restricted to ever-smokers, with an OR of 2.58 (95%CI: 1.27-5.25) for the carriers of His allele among smokers, and an OR of 0.86 (95%CI: 0.45-1.64) among never-smokers (p value of heterogeneity among the two estimates = 0.03). The gene-gene interaction analyses demonstrated that individuals with combined GSTT1 null and NAT2 slow acetylators had an additional increased risk of gastric cancer, with an OR of 3.00 (95%CI: 1.52-5.93) and an AP of 52%. Conclusion: GSTT1, SULT1A1 and NAT2 polymorphisms appear to modulate individual's susceptibility to gastric cancer in this Italian population, particularly when more than one unfavourable genotype is present, or when combined with cigarette smoke. The increased risk for the carriers of CYP2E1*5A or *6 alleles among drinkers need to be confirmed by larger prospective studies

    CYP1A1, CYP2E1, GSTM1, GSTT1, EPHX1 exons 3 and 4, and NAT2 polymorphisms, smoking, consumption of alcohol and fruit and vegetables and risk of head and neck cancer

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    As risk-modifiers of alcohol and tobacco effects, metabolic genes polymorphisms were investigated as susceptibility candidates for squamous cell carcinoma of the head and neck (SCCHN)
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