Raman spectroscopy and molecular dynamics simulations of aqueous two-phase systems for the purification of phosphoric acid.

In this work, Raman spectroscopy and molecular dynamics simulations were used to elucidate key interactions between polyethylene glycol (PEG) and phosphoric acid (H3PO4) in aqueous two-phase systems for the extraction of phosphoric acid. Extensive molecular dynamics simulations were performed, and radial distribution functions as well as hydrogen bonds between PEG and other molecules were measured. Experimental data were used in combination with the slope method to infer PEG-H3PO4 interactions, and the interpretation is consistent with molecular simulation results. Based on our experimental and simulation results, we propose a solvation mechanism governed by hydrogen bonding interactions: at low concentrations of H3PO4 within the polymer-rich aqueous solution, entropy dominates and phosphoric acid molecules have weak interactions with PEG; as the concentration of phosphoric acid increases above a certain critical value, enthalpy dominates with PEG molecules interacting strongly with H3PO4 molecules via hydrogen bonds.

The impact of immigration and vaccination in reducing the incidence of hepatitis B in Catalonia (Spain).

BACKGROUND: The Hepatitis B virus (HBV) infection is a major cause of liver disease and liver cancer worldwide according to the World Health Organization. Following acute HBV infection, 1-5% of infected healthy adults and up to 90% of infected infants become chronic carriers and have an increased risk of cirrhosis and primary hepatocellular carcinoma. The aim of this study was to investigate the relationship between the reduction in acute hepatitis B incidence and the universal vaccination programme in preadolescents in Catalonia (Spain), taking population changes into account, and to construct a model to forecast the future incidence of cases that permits the best preventive strategy to be adopted. METHODS: Reported acute hepatitis B incidence in Catalonia according to age, gender, vaccination coverage, percentage of immigrants and the year of report of cases was analysed. A statistical analysis was made using three models: generalized linear models (GLM) with Poisson or negative binomial distribution and a generalized additive model (GAM). RESULTS: The higher the vaccination coverage, the lower the reported incidence of hepatitis B (p <0.01). In groups with vaccination coverage > 70%, the reduction in incidence was 2-fold higher than in groups with a coverage <70% (p <0.01). The increase in incidence was significantly-higher in groups with a high percentage of immigrants and more than 15% (p <0.01) in immigrant males of working age (19-49 years). CONCLUSIONS: The results of the adjusted models in this study confirm that the global incidence of hepatitis B has declined in Catalonia after the introduction of the universal preadolescent vaccination programme, but the incidence increased in male immigrants of working age. Given the potential severity of hepatitis B for the health of individuals and for the community, universal vaccination programmes should continue and programmes in risk groups, especially immigrants, should be strengthened.

[Tuberculosis in Barcelona: a predictive model based on temporal series]. / Tuberculosis en Barcelona: modelo predictivo basado en series temporales.

Tuberculosis (TB) continues to cause millions of new cases and deaths worldwide every year. The World Health Organization (WHO) has recently estimated that in 2007 9,273,000 cases (incidence 139/100,000 inhabitants) and 1,772,000 deaths were attributed to TB and, in the previous year, the absolute figure was slightly lower (9,240,000 cases) and the incidence somewhat higher (140/100,000), making it difficult to determine whether there was a reduction or not. The objective of this study was to apply fovecasting models to TB, differentiating between indigenous and immigrant subjects, in a city in which the annual number of cases has been recorded since 1987. Adjusted segmented regression (piecewise regression) was applied to the series of new cases in the indigenous and immigrant populations of Barcelona. The evolution of TB differed radically; whereas in the indigenous population there was a downward trend, coinciding with the reduction in new of cases of AIDS, in immigrants there was an upward trend. The estimated number of new cases in 2009 was 168 (95% CI 109 - 227) in indigenous subjects and 227 (95% CI, 180 - 275) in immigrants.

Estimated incidence of hepatitis A virus infection in Catalonia.

PURPOSE: Hepatitis A normally is underreported by statutory disease reporting systems. The objective of this study is to estimate the incidence of hepatitis A virus (HAV) infection from prevalence surveys of infection carried out in representative samples of the population in 1989, 1996, and 2002 and the reported disease incidence during 1991 to 2003 in Catalonia. METHODS: The real incidence of the infection was estimated from the reported incidence adjusted by the prevalence of susceptible individuals and the probability of presenting clinical manifestations. The bootstrap resampling technique was used to calculate 95% confidence intervals (CIs) of reported, clinical, and all infection cases. RESULTS: The infection rate estimated by the bootstrap method was 31.1/100,000 person-years (bootstrap studentized 95% CI, 19.4-56.0), and the rate of clinical hepatitis was 20.0/100,000 person-years (95% CI, 11.8-39.9), rates that were 6.3 and 4.1 times greater than the reported rate during the same period, respectively. CONCLUSIONS: In children younger than 5 years, the estimated infection rate was 13.8 times greater than the reported rate. Combined use of reported cases and results of seroprevalence surveys suggest that underreporting of HAV infection is substantial in Catalonia, especially in children younger than 5 years.

Influenza vaccine coverage, influenza-associated morbidity and all-cause mortality in Catalonia (Spain).

The objective of this work was to study the behaviour of influenza with respect to morbidity and all-cause mortality in Catalonia, and their association with influenza vaccination coverage. The study was carried out over 13 influenza seasons, from epidemiological week 40 of 1994 to week 20 of 2007, and included confirmed cases of influenza and all-cause mortality. Two generalized linear models were fitted: influenza-associated morbidity was modelled by Poisson regression and all-cause mortality by negative binomial regression. The seasonal component was modelled with the periodic function formed by the sum of the sinus and cosines. Expected influenza mortality during periods of influenza virus circulation was estimated by Poisson regression and its confidence intervals using the Bootstrap approach. Vaccination coverage was associated with a reduction in influenza-associated morbidity (p<0.001), but not with a reduction in all-cause mortality (p=0.149). In the case of influenza-associated morbidity, an increase of 5% in vaccination coverage represented a reduction of 3% in the incidence rate of influenza. There was a positive association between influenza-associated morbidity and all-cause mortality. Excess mortality attributable to influenza epidemics was estimated as 34.4 (95% CI: 28.4-40.8) weekly deaths. In conclusion, all-cause mortality is a good indicator of influenza surveillance and vaccination coverage is associated with a reduction in influenza-associated morbidity but not with all-cause mortality.

Evaluation of particulate acellular vaccines against Brucella ovis infection in rams.

The attenuated Brucella melitensis Rev 1 vaccine, used against brucellosis infection, interferes with serological diagnosis tests, may induce abortions in pregnant animals, and may infect humans. In order to overcome these drawbacks, we developed acellular vaccines based on a Brucella ovis antigenic complex (HS) containing outer membrane proteins and R-LPS entrapped in poly(anhydride) conventional and mannosylated nanoparticles (NP-HS and MAN-NP-HS) or in poly(epsilon-caprolactone) microparticles (HS-PEC) as antigen delivery systems and immunoadjuvants. Brucellosis free rams were vaccinated subcutaneously with a single dose of particles containing 3mg of HS, and challenged 6 months thereafter. Protection was evaluated by clinical, bacteriological and serological examinations, in comparison with non-vaccinated control rams. HS-PEC vaccine induced protection (7 out of 13 animals were infected) equivalent to that induced by the reference Rev 1 vaccine (8/14). In contrast, animals immunized with NP-HS were not protected, showing similar results to that obtained in the control unvaccinated rams. Furthermore HS-PEC vaccine did not interfere against B. melitensis serodiagnostic tests. In summary, HS-PEC microparticles could be used as a safe and effective vaccine against brucellosis in rams.