Partitioning of metal species during an enriched fuel combustion experiment. speciation in the gaseous and particulate phases

Combustion processes are the most important source of metal in the atmosphere and need to be better understood to improve flue gas treatment and health impact studies. This combustion experiment was designed to study metal partitioning and metal speciation in the gaseous and particulate phases. A light fuel oil was enriched with 15 organometallic compounds of the following elements: Pb, Hg, As, Cu, Zn, Cd, Se, Sn, Mn, V, Tl, Ni, Co, Cr, and Sb. The resulting mixture was burnt in a pilot-scale fuel combustion boiler under controlled conditions. After filtration of the particles, the gaseous species were sampled in the stack through a heated sampling tube simultaneously by standardized washing bottles-based sampling techniques and cryogenically. The cryogenic samples were collected at -80 degrees C for further speciation analysis by LT/GC-ICPMS. Three species of selenium and two of mercury were evidenced as volatile species in the flue gas. Thermodynamic predictions and experiments suggest the following volatile metal species to be present in the flue gas: H2Se, CSSe, CSe2, SeCl2, Hg(0), and HgCl2. Quantification of volatile metal species in comparison between cryogenic techniques and the washing bottles-based sampling method is also discussed. Concerning metal partitioning, the results indicated that under these conditions, at least 60% (by weight) of the elements Pb, Sn, Cu, Co, Tl, Mn, V, Cr, Ni, Zn, Cd, and Sb mixed to the fuel were found in the particulate matter. For As and Se, 37 and 17%, respectively, were detected in the particles, and no particulate mercury was found. Direct metal speciation in particles was performed by XPS allowing the determination of the oxidation state of the following elements: Sb(V), Tl(III), Mn(IV), Cd(II), Zn(II), Cr(III), Ni(II), Co(II), V(V), and Cu(II). Water soluble species of inorganic Cr, As, and Se in particulate matter were determined by HPLC/ICP-MS and identified in the oxidation state Cr(III), As(V), and Se(IV).     

Economic and health risk trade-offs of swim closures at a Lake Michigan beach

This paper presents a framework for analyzing the economic, health, and recreation implications of swim closures related to high fecal indicator bacteria (FIB) levels. The framework utilizes benefit transfer policy analysis to provide a practical procedure for estimating the effectiveness of recreational water quality policies. Evaluation criteria include the rates of intended and unintended management outcomes, whether the chosen protocols generate closures with positive net economic benefits to swimmers, and the number of predicted illnesses the policy is able to prevent. We demonstrate the framework through a case study of a Lake Michigan freshwater beach using existing water quality and visitor data from 1998 to 2001. We find that a typical closure causes a net economic loss among would-be swimmers totaling dollars 1274-37,030/day, depending on the value assumptions used. Unnecessary closures, caused by high indicator variability and a 24-h time delay between when samples are taken and the management decision can be made, occurred on 14 (12%) out of 118 monitored summer days. Days with high FIB levels when the swim area is open are also common but do relatively little economic harm in comparison. Also, even if the closure policy could be implemented daily and perfectly without error, only about 42% of predicted illnesses would be avoided. These conclusions were sensitive to the relative values and risk preferences that swimmers have for recreation access and avoiding health effects, suggesting a need for further study of the impacts of recreational water quality policies on individuals.     

Dietary total antioxidant capacity as a tool in health outcomes in middle-aged and older adults: A systematic review

The dietary total antioxidant capacity (TAC) has been a useful tool in epidemiological studies. To assess whether the TAC is associated with chronic diseases in middle-aged and older adults carried out a systematic review of articles indexed in MEDLINE and Science Direct. Of the 104 articles found, nine were included to meet the inclusion criteria. There was variation among the items on the sample size, sample origin, use of statistical tests, analysis of different outcomes and the use of assays to evaluate the TAC, which brought limitations to the comparability of results on the association of TAC with the outcomes of interest. However, in six studies we found an inverse association between TAC and the risk of chronic diseases, showing that this method has great potential for clinical applications and public health.     

Effect of amino acid,pH and mineral salts on glass transition and flow behaviour of soy protein concentrate

The objective of this study was to assess the effect of proline, mineral salts (NaCl and Na₂SO₄) and pH combined with moisture content on the glass transition temperature (T_g) and flow‐starting temperature (T_f) of soy protein concentrate (SPC). Initial screening of the variables based on fractional factorial design showed insignificant effect of NaCl on T_g and T_f. The design was extended to a face‐centred central composite design (CCD) excluding NaCl and data evaluated by use of response surface methodology. The established model for T_g (R² = 0.824) shows significant negative first‐order effects of moisture, proline and Na₂SO₄, and a positive interaction effect of moisture and Na₂SO₄. The T_f model (R² = 0.937) shows significant negative first‐order effects of moisture and proline, a positive first‐order and negative square effect of pH, and a negative interaction effect of moisture and proline. The main effect on T_g and T_f was 2.2 and 1.3 times higher, respectively, for moisture compared to proline. The study confirms that proline (or other free amino acids) can replace moisture as protein plasticiser in the extrusion process. Minor effects can also be obtained by reduction in pH.     

Rapid Determination of Bitterness in Beer Using Fluorescence Spectroscopy and Chemometrics

Two fluorescence spectroscopic methods with the aim to develop a fast quantitative determination of bitterness in beer were tested. The first method was based on autofluorescence of the diluted and degassed beer samples without any further processing. A total of 21 dark and light beer samples were analyzed and multivariate Partial Least Squares (PLS) regression models to bitterness in form of international bitter units (IBU) were performed. A prediction error in the form of Root Mean Square Error of Cross‐Validation (RMSECV) of 2.77 IBU was obtained using six PLS components. Focusing only on the light beer samples the RMSECV was reduced to 1.81 IBU. The second method developed was based on addition of europium to induce delayed fluorescence signals in the beer samples. PLS models yielded an RMSECV of 2.65 IBU for all beers, while a model on the light beer samples gave an RMSECV of 1.75 IBU. The obtained prediction errors were compared to the errors given in the literature for the traditional extraction method of determining IBU.     

Soy protein cold-set hydrogels as controlled delivery devices for nutraceutical compounds

The release of riboflavin from soy protein hydrogels of filamentous or particulate microstructure was investigated under gastric and intestinal conditions in the presence or absence of digestive proteases. Microscopic examination showed riboflavin arranged into crystals dispersed randomly throughout the gels. Rheological analysis revealed that the riboflavin load weakened the gel networks, which led to gel disintegration during hydro-swelling tests at pH 7.5. Dissolution tests showed that riboflavin release was faster at pH 7.5 than at pH 1.2 for both gels. Initial release was faster from particulate gels, due to their higher porosity and eroding granular texture. The release mechanisms involved in riboflavin release were diffusion and matrix degradation for both gels at pH 1.2 and pH 7.5. In the presence of pepsin at pH 1.2, both gel types provided good protection of riboflavin for at least 6 h, while both were digested in the presence of pancreatin at pH 7.5. These results suggest that both gels might be useful for transporting bioactive molecules through the gastrointestinal tract and delivering them in the small intestine. Considering their non-synthetic nature, they should be of great interest to developers of innovative functional foods.     

A roadmap on smart textiles

Though industrial exploitation of smart textile systems is still in its infancy, the technological implementation is increasing. This is the result of substantial research and development investments directed towards this emerging field. In order to stimulate the progress in smart textiles, emerging developments need to be identified and selectively strengthened. Hence, this issue reports on a three-dimensional roadmap on smart textiles. It aims at contributing to set future actions in research, education and technology development. Research activities and technological developments are mapped, barriers and drivers of technological, strategic and societal and economical origins are identified. Finally, recommendations are phrased on how to overcome barriers and to progress in the field of smart textiles.