Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO2.

Transition metal oxides are among the most promising solar materials, whose properties rely on the generation, transport and trapping of charge carriers (electrons and holes). Identifying the latter's dynamics at room temperature requires tools that combine elemental and structural sensitivity, with the atomic scale resolution of time (femtoseconds, fs). Here, we use fs Ti K-edge X-ray absorption spectroscopy (XAS) upon 3.49 eV (355 nm) excitation of aqueous colloidal anatase titanium dioxide nanoparticles to probe the trapping dynamics of photogenerated electrons. We find that their localization at Titanium atoms occurs in <300 fs, forming Ti(3+) centres, in or near the unit cell where the electron is created. We conclude that electron localization is due to its trapping at pentacoordinated sites, mostly present in the surface shell region. The present demonstration of fs hard X-ray absorption capabilities opens the way to a detailed description of the charge carrier dynamics in transition metal oxides.

An in vitro evaluation of the antibacterial activity of the non-volatile phenolic fraction from rosemary leaves.

In this study, the aim was to evaluate the antimicrobial action of the non-volatile phenols of rosemary leaves against two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and two Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis). Three extracts with different phenolic compositions were tested. By the agar disc diffusion method, Gram-positive bacteria were more sensitive to the extracts, and S. epidermidis showed the highest inhibition zones. Overall, all the extracts tested by the broth dilution method showed higher activity than results from the agar disc diffusion method. The minimal bactericidal concentration values indicated that E. coli was the most susceptible strain. This study demonstrated that the flavonoidic fraction of rosemary leaves does not play a crucial role as antimicrobial agents against these microorganisms. The most active extract was characterised by the highest amount of non-volatile terpenoidic compounds.

[Influenza vaccination: coverage and risk perception among students of the health professions at Florence University, Italy]. / Vaccinazione antinfluenzale: copertura e percezione del rischio tra gli stusenti dell' area sanitaria dell' Univesità di Firenze.

BACKGROUND: It is well demonstrated that influenza vaccination coverage among health care workers and health professions students continues to be low, despite WHO and CDCs strongly recommend flu shot for these categories. Aim of this work is to investigate among students the flu risk perception (both seasonal and 2009 H1N1), knowledge and attitudes towards vaccination and the main factors of acceptance or refusal of the vaccination. METHODS: The study population includes 662 health professions students from the University of Florence. Survey was conducted from October 2010 to March 2011 by an anonymous questionnaire consisting of multiple-choice questions. Statistical analysis was performed in SPSS 19 and the dichotomous variables were analysed using chi2 test and Fisher's exact test. RESULTS: The proportion of students vaccinated against seasonal flu was 10.3% in 2007, 12.1% in 2008, 12.6% in 2009. A lower percentage (9.6%) has received the H1N1v vaccine. In 2009, the majority of the vaccinated students chose to get immunized in order to protect themselves (84.8% for seasonal flu and 71% for H1N1) and other people (over 77% both for seasonal and H1N1). The most common reason to refuse vaccination was to perceive a low disease risk (62.5% for seasonal and 61.9% for H1N1). CONCLUSIONS: Our findings suggest the need to promote a better and accessible offer and to extend flu shot to students during vaccination campaign, in order to increase the primary prevention through vaccination among future's health care workers.

Serum trace elements and risk of malnutrition in institutionalised elderly.

OBJECTIVE: The objective of this work is to evaluate the association between Selenium (Se)-, Copper (Cu)- and Zinc (Zn)-circulating concentrations and indicators of nutritional status. SUBJECTS/METHODS: This study enroled 428 institutionalised elderly. The diagnostic tools used are a form to collect data regarding gender, age, duration of stay in nursing home, number of prescribed drugs, chronic diseases, Mini Nutritional Assessment (MNA), anthropometric measurements, albumin, transferrin and serum concentrations of Se, Cu and Zn. The collected data were analysed with descriptive assessments of the differences χ(2), Student's t-test and analysis of variance. Multivariate linear regression were performed to evaluate the association between the concentrations of each trace elements and the other variables. RESULTS: The study population was represented by 327 women and 101 men, of whom 13.8% were 65-75 years old and 47.4% were older than 85 years. According to the MNA score, 58.4% were at risk of malnutrition and 21.3% were malnourished. The results show a significant reduction in the average concentrations of Se and Zn in women when the nutritional status gets worse. The same trend, although not statistically significant, is also observed in men. In both genders, the Cu concentration does not show a statistically significant association with nutritional status. Multivariate linear regression show some positive or negative associations. CONCLUSIONS: Our study seems to confirm the association between Se and nutritional status, as well as with some blood chemistry parameters. The length of institutionalisation seems to be an independent predictor of Se concentration.

Body composition in subjects with anorexia nervosa: bioelectrical impedance analysis and dual-energy X-ray absorptiometry.

OBJECTIVE: To evaluate the applicability and validity of bioelectrical impedance analysis (BIA) compared with dual-energy X-ray absorptiometry (DXA) in a population of girls with restrictive anorexia nervosa (AN). METHODS: A total of 30 girls (11-19 years old) with AN were enrolled. DXA and BIA (BIA software and the Deurenberg equations) were used to estimate the body composition. The correlation between the methods was assessed by Pearson's correlation coefficient and the Bland-Altman method. RESULTS: The mean FFM estimates were 33.2 kg (BIA software), 32.8 kg (BIA, Deurenberg equation) and 33.1 kg (DXA). The mean FM values were 5.6 kg (BIA software), 6.2 kg (BIA, Deurenberg equation) and 6.4 kg (DXA). There was a high correlation between the FFM values estimated with the two methods (BIA software vs DXA r=0.917, p<0.001; Deurenberg equation vs DXA r=0.931, p<0.001). For the FFM, the limits of agreement were equal to ±3.34 kg for the BIA software and ±2.96 kg for the Deurenberg equation. For the FM, the limits of agreement were equal to ±4.60 kg for the BIA software and ±3.82 kg for the Deurenberg equation. CONCLUSION: The results show a good correlation between DXA and BIA. BIA seems to be a valid alternative for epidemiological and clinical evaluations.

Characterization of volatile fraction of typical Irpinian wines fermented with a new starter yeast.

Non-Saccharomyces yeasts are microorganisms that play an important role in the fermentation dynamics, compositions and flavour of wine. The aromatic compounds responsible for varietal aroma in wine are mainly terpenes, of which the most important group are the monoterpenes because of their volatility and odour if present in a free form. In fact, some terpenyl-glycosides do not contribute to the aroma unless they are hydrolysed. The glycosylated form of terpenes can be converted by hydrolysis with ß-glycosidases produced by yeasts during the winemaking process, into aromatic compounds. In this study we utilized a non-Saccharomyces yeast, with a high extra-cellular glycosidase activity, isolated from grapes of cultivars typical of Irpinia region. This strain, identified as a Rhodotorula mucillaginosa (strain WLR12), was used to carry out an experimental winemaking process and the results were compared with those obtained with a commercial yeast starter. Chemical and sensorial analysis demonstrated that the wines produced with WLR12 strain had a more floral aroma and some sweet and ripened fruit notes compared to those obtained with commercial yeast. The data also showed an increasing of the free terpenes fraction that, however, did not significatively modify the bouquet of the wines.

Bioelectrical Impedance Vector Analysis and Mini Nutritional Assessment in elderly nursing home residents.

OBJECTIVE: The aim of this study was to establish the presence of malnutrition in elderly institutionalized people through Mini Nutritional Assessment (MNA) scores and to observe the changes of nutritional status through the Bioelectrical Impedance Vector Analysis (BIVA). DESIGN: Observational study. SETTING: Nursing home located in the territory of Florence (Italy). PARTICIPANTS: 463 elderly individuals from twelve nursing homes, all aged 65 yrs or over. MEASUREMENTS: We carried out the MNA and measured the bioelectrical parameters of resistance (R) and reactance (Xc), with standard, tetrapolar analysis at 50 kHz frequency; these bioelectrical parameters were interpreted according to BIVA analysis. RESULTS: According to the MNA score, 23.1% of the women and 20.4% of the males are malnourished (MNA < 17), 60.0% and 52.8%, respectively, are at risk for malnutrition (17 ≤ MNA ≤ 23.5). Malnourished, at-risk and well-fed subjects differ significantly (p < 0.05) in their mean scores obtained in each of the MNA areas. Fifteen of eighteen MNA items show a significant correlation to the total MNA score (p < 0.001). The items not significantly related to the MNA global score were those concerning protein intake, independence and number of medicinal drugs taken. In both genders, the decrease of the MNA score increases the proportion of subjects placed outside the 95% confidence ellipse on the BIVA tolerance graph. CONCLUSION: A routine assessment of nutritional status through BIVA analysis combined with more "traditional" tools like the MNA could be useful for recognizing malnutrition and the risk of malnutrition in the elderly as these instruments provide complete information and are easy to use even with heavily impaired subjects.

[Body composition, nutritional habits and functional abilities in a sample of eight year old children]. / Composizione corporea, abitudini alimentari e abilita funzionali in un campione di bambini di 8 anni.

Aim of this study is the evaluation of body composition (proxy of nutritional status) and its correlation with functional abilities in a sample of 8-year-old children living in a florentine municipality. We have collected, for each subject, anthropometric variables (weight, height) and carried out bioelectrical impedance test and a group of physical tests to measure strength and physical ability. The results of vectorial interpretation of BIA, together with the analysis of the so called fitness tests, show a comprehensive good body composition and a very low prevalence of obesity for both genders. This fact is confirmed also by data about living and nutrition habits: scarce use of PC and TV (less than two hours a day) and, on the other hand, enough time spent to play in open spaces and to make sport.

[Evaluation of the Yersinia enterocolitica pathogenicity through some phenotypic and genotypic characters: CRMOX agar positivity and presence of the ail gene]. / Valutazione della patogenicità di Yersinia enterocolitica attraverso alcuni caratteri fenotipici e genotipici: positività su CRMOX agar e presenza del gene ail.

Sixty-nine strains of Y. enterocolitica isolated from environmental and human matrices (waste water, food and faeces) were studied in order to evidence the presence of ail gene, calcium-dependency and Congo Red absorption for pathogenic strains identification. Out of 24 clinical strains, the ail gene was present in 21 (87%), among which 79% were CRMOX-positive as well. On the contrary, none of the 45 environmental strains showed the ail gene although only one (isolated from cooked vegetables) was CRMOX agar positive. Our results confirmed the importance of molecular methods to evidence the Y. enterocolitica pathogenic strains. However, our study pointed also the utility to consider the approach of classic bacteriology, like the subcoltivation on CRMOX agar to show calcium-dependency and Congo Red absorption. In particular, when dealing with environmental isolates, that medium will be useful as a preliminary screening to identify those isolates which need further research to indicate their pathogenic potential by the use of more complex but also more expensive molecular methods.

Performance of horizontal subsurface-flow treatment wetlands in fecal bacteria removal.

This work evaluated sub-surface flow (SSF) constructed wetlands and activated sludge plant efficiency in pathogen removal. The two were also compared. The removal of fecal bacteria (total coliforms, fecal coliforms, fecal streptococci) was evaluated. Analysis was carried out during one year by determining the amount of bacteria in the inflow and the outflow of four systems: three SSF systems (two were pilot plants and one a fully operating plant) and an activated sludge plant. MPN techniques were used to determine the quantity-value of the microorganisms. Percentages of fecal bacteria removal in wetlands systems were as good as (and sometimes better than) those recorded in the activated sludge plant. Optimal values of these bacteria were obtained in the outflow of the post-treatment pilot plant: very high bacterial removal percentages (>99%) were recorded. SFS constructed wetlands are a valid solution for the final treatment of the outflow of existing plants.