110 research outputs found

    Angular dependence of copper surface damage induced by an intense coherent thz radiation beam

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    In this work, we show the damage induced by an intense coherent terahertz (THz) beam on copper surfaces. The metallic surface was irradiated by multiple picosecond THz pulses generated by the Free Electron Laser (FEL) at the ISIR facility of the Osaka University, reaching an electric field on the sample surface up to ~4 GV/m. No damage occurs at normal incidence, while images and spectroscopic analysis of the surface point out a clear dependence of the damage on the incidence angle, the electric field intensity, and polarization of the pulsed THz radiation. Ab initio analysis shows that the damage at high incidence angles could be related to the increase of the absorbance, i.e., to the increase of the temperature around or above 1000◦ C. The experimental approach we introduced with multiple fast irradiations represents a new powerful technique useful to test, in a reproducible way, the damage induced by an intense electric gradient on copper and other metallic surfaces in view of future THz-based compact particle accelerators

    Defining Configurable Virtual Reality Templates for End Users

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    This paper proposes a solution for supporting end users in configuring Virtual Reality environments by exploiting reusable templates created by experts. We identify the roles participating in the environment development and the means for delegating part of the behaviour definition to the end users. We focus in particular on enabling end users to define the environment behaviour. The solution exploits a taxonomy defining common virtual objects having high-level actions for specifying event-condition-Action rules readable as natural language sentences. End users exploit such actions to define the environment behaviour. We report on a proof-of-concept implementation of the proposed approach, on its validation through two different case studies (virtual shop and museum), and on evaluating the approach with expert users

    Dietary intake of folate, vitamin B6, and vitamin B12, genetic polymorphism of related enzymes, and risk of breast cancer: a case-control study in Brazilian women

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    <p>Abstract</p> <p>Background</p> <p>Several studies have determined that dietary intake of B vitamins may be associated with breast cancer risk as a result of interactions between <it>5,10-methylenetetrahydrofolate reductase (MTHFR) </it>and <it>methionine synthase </it>(<it>MTR</it>) in the one-carbon metabolism pathway. However, the association between B vitamin intake and breast cancer risk in Brazilian women in particular has not yet been investigated.</p> <p>Methods</p> <p>A case-control study was conducted in São Paulo, Brazil, with 458 age-matched pairs of Brazilian women. Energy-adjusted intakes of folate, vitamin B<sub>6</sub>, and vitamin B<sub>12 </sub>were derived from a validated Food Frequency Questionnaire (FFQ). Genotyping was completed for <it>MTHFR </it>A1298C and C677T, and <it>MTR </it>A2756G polymorphisms. A logistical regression model was used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs).</p> <p>Results</p> <p>Neither dietary intake of folate, vitamin B<sub>6</sub>, or vitamin B<sub>12 </sub>nor <it>MTHFR </it>polymorphisms were independently associated with breast cancer risk. Analysis stratified by menopausal status showed a significant association between placement in the highest tertile of folate intake and risk of breast cancer in premenopausal women (OR = 2.17, 95% CI: 1.23–3.83; <it>P</it><sub><it>trend </it></sub>= 0.010). The <it>MTR </it>2756GG genotype was associated with a higher risk of breast cancer than the 2756AA genotype (OR = 1.99, 95% CI = 1.01–3.92; <it>P</it><sub><it>trend </it></sub>= 0.801), and statistically significant interactions with regard to risk were observed between the <it>MTHFR </it>A1298C polymorphism and folate (P = 0.024) or vitamin B<sub>6 </sub>(P = 0.043), and between the <it>MTHFR </it>C677T polymorphism and folate (P = 0.043) or vitamin B<sub>12 </sub>(P = 0.022).</p> <p>Conclusion</p> <p><it>MTHFR </it>polymorphisms and dietary intake of folate, vitamin B<sub>6</sub>, and vitamin B<sub>12 </sub>had no overall association with breast cancer risk. However, increased risk was observed in total women with the <it>MTR </it>2756GG genotype and in premenopausal women with high folate intake. These findings, as well as significant interactions between <it>MTHFR </it>polymorphisms and B vitamins, warrant further investigation.</p

    MTHFR polymorphisms in gastric cancer and in first-degree relatives of patients with gastric cancer

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    Two common mutations, 677 C→T and a1298 A→C, in the methylenetetrahydrofolate reductase gene (MTHFR) reduce the activity of MTHFR and folate metabolism. Familial aggregation in a variable but significant proportion of gastric cancer (GC) cases suggests the importance of genetic predisposition in determining risk. In this study, we evaluate MTHFR polymorphisms in 57 patients with a diagnosis of GC, in 37 with a history of GC in first-degree relatives (GC-relatives), and in 454 blood donors. Helicobacter pylori (HP) infection was also determined. An increased risk was found for 677TT in GC patients with respect to blood donors (odds ratio (OR) = 1.98), and statistical significance was sustained when we compared sex–age-matched GC patients and donors (OR = 2.37). The 677TT genotype association with GC was found in women (OR = 3.10), while a reduction in the 667C allele frequency was present in both the sex. No statistically significant association was detected when 677–1298 genotype was stratified by sex and age. Men of GC-relatives showed a higher 1298C allele frequency than donors (OR = 4.38). Between GC and GC-relatives, HP infection frequency was similar. In conclusion, overall findings support the hypothesis that folate plays a role in GC risk. GC-relatives evidence a similar 677TT frequency to that found in the general population

    Lung function assessed by home forced oscillation and self reported symptoms during COPD exacerbations

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    CHROMED (clinical trials for elderly people with multiple diseases, www.chromed.eu) is an EU-funded project involving 9 partners from 7 European countries aimed at evaluating the impact of a new home care approach to reduce costs and improve quality of life in elderly patients with COPD and comorbidity. The trial involves 300 patients with a prior history of exacerbations randomly assigned to a monitoring or observational arm. Monitored patients performed daily self-assessment of lung mechanics with a FOT (Forced Oscillation Technique) device (RESMON PRO DIARY, Restech srl, Italy) and completed a symptom diary card on touchscreen device (HOME PATIENT MONITOR, EBM srl, Italy). Any detected worsening in lung mechanics generated an alert triggering a phone interview directed at verifying the patient's status and optimizing treatment. By the end of March 2015, 70 monitored patients had completed the trial resulting in 16198 measurements with an adherence of 90.1%. Based on lung mechanics, 311 worsening events were detected, resulting in 0.65±0.3 alerts/patient/month. At least one major symptom (dyspnea, sputum purulence and volume) was reported in 70% of events and 41% were associated with an exacerbation according to diary cards (Seemungal et al., Am J Respir Crit Care Med 1998). A total of 77 exacerbations were confirmed during the phone interview and treated, but 48% of them were not associated with an exacerbation defined by diary cards only. These results suggest that a significant percentage of exacerbations cannot be identified by diary cards only. Self-assessment of lung mechanics using FOT provides complementary information which can be useful to manage COPD patients at home

    Key enzymes catalyzing glycerol to 1,3-propanediol

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