Modeling of the α-lactalbumin and β-lactoglobulin protein separation

This work used the General Rate Model (GRM) to evaluate the experimental data of α-lactalbumin (α-la) and β-lactoglobulin (β-lg) mass transfer using size exclusion chromatography (SEC). The chromatographic simulation has become necessary in large scale production processes. Mathematical models have been used for the optimization and control of different operating conditions of the process, as well as providing calculations for the process scale-up. For the SEC experiments, the aqueous biphasic system was composed of polyethylene glycol 1500 g/mol, potassium phosphate and whey protein isolate. The polymeric phase was enriched with α-la and the saline phase with β-lg. The experiments were conducted using a glass column packed with the Shepadex G-25® gel. Both proteins were quantified by reverse phase liquid chromatography. The experimental data were fitted by non-linear regression, using the successive quadratic programming algorithm. The mass transfer model utilized represented adequately the SEC experimental results.The authors would like to thank FAPEMIG, FAPERJ and CNPq for the financial support of this work

Urinary schistosomiasis in Guinea Bissau

Urogenital schistosomiasis due to Schistosoma (S.) haematobium is among the most prevalent parasitoses in sub-Saharan Africa. The pathology is characterized by serious and irreversible lesions in the urogenital tract induced by chronic infection with the parasite that can eventually lead to renal failure due to hydronephrosis and to squamous cell carcinoma of the bladder. Considering the frequency and severe morbidity observed already in young children, the purpose of this pilot study was to assess the prevalence and morbidity of S. haematobium infection in Guinea Bissau. A baseline survey was conducted during September 2011. A randomly selected sample of 90 children aged 6–15 years old was included in this study. Prevalence of S. haematobium infection was 20% (18/90). It was higher in older children (median age in years: 15.4 2.71 vs. 9.3 2.22; P < 0.001), a significant gender difference in prevalence and intensity was not found. The predominant symptom was haematuria (87.1%), this symptom being strongly associated with S. haematobium infection (P < 0.01). Anthropometric examination revealed that growth in infected boys was impaired as compared to non-infected boys (median height in cm: 123.3 21.07 vs. 134.71 15.1) (P < 0.05). To our knowledge this is the first epidemiologic report of S. haematobium infection in Guinea Bissau. Considering the high prevalence of S. haematobium infections in Guinea Bissau and the long-term risks, including renal failure and bladder cancer, our results indicate that this population should be targeted for follow-up and implementation of measures for treatment and control of schistosomiasis

The exposure of the hybrid detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The "hybrid" detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data collected during operations, such as the status of the fluorescence detector, background light and atmospheric conditions, that are used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic

Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

Assessment of the Performance of Osmotically Driven Polymeric Membrane Processes

The universal water scarceness and the extensive ordeals with energy cost in conjunction with the undesirable ecological effects have advanced the improvement of novel osmotically driven membrane processes. Membrane processes which are osmotically driven are developing type of membrane separation procedures that apply concentrated brines to separate liquid streams. They are adaptable in various applications; hence, allow them to be an attractive substitute for drug release, wastewater treatment and the production and recovery of energy. Although, internal concentration polarization (ICP) occurs in membrane practises which are osmotically driven as a consequence of hindered diffusion of solute in a porous stratum, their interest has even increased. Here we review two natural membrane processes that are osmotically driven; Forward osmosis (FO) and Pressure retarded osmosis (PRO). Thus, the major points are as follows: 1) it was highlighted in this review, that the major developments in FO process, important for the process efficiency is to choose a suitable membrane and draw solution. 2) The recent evaluation, understanding and optimizing the activities of fouling throughout the osmotic dilution of seawater employing FO was discussed. 3) Recent advancements of FO in the application of food processing was reviewed. 4) It was highlighted that the main concept of PRO for power generation is the energy of mixing that offers great assessment of the nonexpansion work which could be generated from mixing; nonetheless, the development of effective membranes with appropriate arrangement and performance is needed for the advancement of PRO process for power generation. 5) One major challenge of osmotically driven membrane processes, most recent developments and model development to predict their performances were discussed