Effect of Pulsed Light Treatment on the Germination of Bacillus subtilis Spores

Food and Bioprocess Technology - The loss of cell culturability (spore counts), spore germination and subsequent vegetative growth of Bacillus subtilis were evaluated after pulsed light (PL)...     

Effect of solidification parameters on the microstructure of directionally solidified Sn-Bi-Zn lead-free solder

Sn-Bi-Zn lead free solder alloy was directionally solidified upward at a constant temperature gradient (G=3.99 K/mm) with a wide range of growth rates (8.3–478.6 μm/s) and at a constant growth rate (V=8.3 μm/s) with a wide range of temperature gradients (1.78–3.99 K/mm) using a Bridgman type directional solidification furnace. Wavelength-Dispersive X-ray Fluorescence spectrometry and X-ray diffraction were used to identify the compositions and phases in the microstructure. Dependence of eutectic spacings (λ) on the growth rate (V), temperature gradient (G) and cooling rate (Ṫ) were determined using linear regression analysis. From the experimental results, it can be concluded that the values of λ decrease with the increasing the values of V, G and Ṫ. The value of λ²V was determined using the measured values of λ and V. The results obtained in the present work have been compared with previous results obtained for binary or ternary alloys.     

Processing cherries (Prunus avium) using supercritical fluid technology. Part 1: Recovery of extract fractions rich in bioactive compounds

In the recent years many studies on cherries revealed that they are rich sources of bioactive compounds with beneficial biological activity.In this work, fractioned high pressure extractions were performed on a traditional sweet cherry variety from Portugal (“Saco”) in order to recover natural ingredients with bioactivity. The methodology employed comprised a first step with supercritical CO₂ followed by a second step where different mixtures of CO₂ and ethanol (10-100%, v/v) were tested. All extractions were performed at 50 °C and 25 MPa during 1 plus 1.5 h and the resulting extracts were then characterized in terms of global yield, phenolic content, antioxidant activity and screened for the presence of perillyl alcohol, a powerful anticancer compound. Moreover, cell-based assays were also performed as preliminary evaluation of potential antiproliferative activity of the cherry extracts.In the first step, lower yields were obtained and the extracts presented lower phenolic and antioxidant activity than those recovered in the second step. The extract obtained with CO₂:EtOH (90:10, v/v) exhibited the highest antioxidant activity (181.4 ± 23.7 μmol TEAC/g) and was the most effective in inhibiting the growth of human colon cancer cells (ED50_96h = 0.20 ± 0.02 mg/mL). Perillyl alcohol was pointed to be one of the major responsible for antiproliferative properties of cherry extracts as it was detected in the most promising products, and polyphenols, in particular sakuranetin and sakuranin, seemed to be the major contributors of the antioxidant capacity.     

Denitrification of high nitrate concentration wastewater using alternative carbon sources

The use of different organic carbon sources in the denitrification of wastewater containing 2500 mg nitrates/L in a SBR was studied. Three alternative sources of carbon were tested: wastewater from a sweet factory, a residue from a soft drinks factory and a residue from a dairy plant. The first two are sugar-rich, whereas the third presents a high content in lactic acid. Maximum specific denitrification rates of between 42 and 48 mg NO₃-N/g VSS h were obtained. The effluents were nitrate-free and very low COD concentrations were obtained in 4–6 h reaction time, especially with the sugar-rich carbon sources. The values of the denitrifier net yield coefficient were higher than when using methanol (0.93–1.75 g VSS_formed/g NO_x-N_reduced). The lowest value was obtained using the lactic acid-rich residue. The optimum COD/N ratios varied between 4.6 for the lactic acid-rich carbon source and 5.5–6.5 for the sugar-rich carbon sources.     

Hartstoffschichten der Zukunft

In der vorliegenden Arbeit konnte gezeigt werden, dass das Schichtsystem (Ti,Al)γ‐Al₂O₃ in Vergleich zum weit verbreitetem Schichtsystem (Ti,Al)N in tribologischen Untersuchungen deutlich besser abschneidet. Vor allem die Adhäsion von Gegenkörpermaterial 1.4301 kann deutlich reduziert werden. Des Weiteren wurde die vielversprechende HPPMS‐Technologie zur Abscheidung nitridischer Hartstoffschichten vorgestellt. In Bezug auf die mechanischen Eigenschaften weist das HPPMS/DC‐Schichtsystem deutliche Vorteile auf. Zur Ermittlung der Phasen‐ und Oxidationsstabilität der Schicht sind Glühversuche in Vakuum und Atmosphäre geplant.     

Removal of ammonium from aqueous solutions with volcanic tuff

This paper presents kinetic and equilibrium data concerning ammonium ion uptake from aqueous solutions using Romanian volcanic tuff. The influence of contact time, pH, ammonium concentration, presence of other cations and anion species is discussed. Equilibrium isotherms adequately fit the Langmuir and Freundlich models. The results showed a contact time of 3h to be sufficient to reach equilibrium and pH of 7 to be the optimum value. Adsorption capacities of 19 mg NH(4)(+)/g were obtained in multicomponent solutions (containing NH(4)(+), Zn(2+), Cd(2+), Ca(2+), Na(2+)). The presence of Zn and Cd at low concentrations did not decrease the ammonium adsorption capacity. Comparison of Romanian volcanic tuff with synthetic zeolites used for ammonium removal (5A, 13X and ZSM-5) was carried out. The removal efficiciency of ammonium by volcanic tuff were similar to those of zeolites 5A and 13X at low initial ammonium concentration, and much higher than those of zeolite ZSM-5.     

Economic Costs of Water-related Health Problems in Mexico: Deficiencies in Potable Water Services and the Costs of Treatment of Diarrhoeas

The paper provides a quantitative estimate of the economic costs of the health problems, especially diarrhoea, attributable to deficiencies in potable water services in Mexico. It is argued that more financial resources should be allocated to improving and extending potable water and sanitation, lack of which are the principal causes of diarrhoeas.