Leaching of lead by ammonium salts and EDTA from Salvinia minima biomass produced during aquatic phytoremediation

Plant biomass harvested after heavy-metal phytoremediation must be considered as a hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable fertilizer or mulch, leaching of lead (Pb) from Salvinia minima biomass was studied by testing water, several aqueous ammonium salts, and EDTA solution as lead extractants. The research was carried out in two phases: (i) a leaching study to determine the lead-extraction efficiency of the different leachants, and (ii) a thermodynamic analysis to identify the likely reactions and stable Pb(II) species formed in the leaching systems of the most efficient leachants. Experimentally, lead concentrations measured in leached biomass and in leachates were significantly different among the various leachants. It was determined that the extraction strength of the leachants followed the order: EDTA>ammonium oxalate>water approximately ammonium nitrate>ammonium acetate, achieving Pb extraction efficiencies of 99%, 70%, 7.2%, 6.9% and 1.3%, respectively, in single-stage extractions. The thermodynamic study indicated that the dominant species produced by the leaching process should be the soluble species PbEDTA2- for EDTA system, and the insoluble Pb(COO)2S precipitate for the oxalate system.     

Concept for facilitating analyst-mediated interpretation of qualitative chromatographic-mass spectral data: an alternative to manual examination of extracted ion chromatograms

A chemometrics-based data analysis concept has been developed as a substitute for manual inspection of extracted ion chromatograms (XICs), which facilitates rapid, analyst-mediated interpretation of GC- and LC/MS(n) data sets from samples undergoing qualitative batchwise screening for prespecified sets of analytes. Automatic preparation of data into two-dimensional row space-derived scatter plots (row space plots) eliminates the need to manually interpret hundreds to thousands of XICs per batch of samples while keeping all interpretation of raw data directly in the hands of the analyst-saving great quantities of human time without loss of integrity in the data analysis process. For a given analyte, two analyte-specific variables are automatically collected by a computer algorithm and placed into a data matrix (i.e., placed into row space): the first variable is the ion abundance corresponding to scan number x and analyte-specific m/z value y, and the second variable is the ion abundance corresponding to scan number x and analyte-specific m/z value z (a second ion). These two variables serve as the two axes of the aforementioned row space plots. In order to collect appropriate scan number (retention time) information, it is necessary to analyze, as part of every batch, a sample containing a mixture of all analytes to be tested. When pure standard materials of tested analytes are unavailable, but representative ion m/z values are known and retention time can be approximated, data are evaluated based on two-dimensional scores plots from principal component analysis of small time range(s) of mass spectral data. The time-saving efficiency of this concept is directly proportional to the percentage of negative samples and to the total number of samples processed simultaneously.     

Pulsed-field gel electrophoresis is more efficient than ribotyping and random amplified polymorphic DNA analysis in discrimination of Pasteurella haemolytica strains

OBJECTIVE: Factors such as size of hyphema, intraocular pressure, initial visual acuity, and use of steroids or antifibrinolytic drugs may be associated with the likelihood of rebleeding in traumatic hyphema. The association of the visual outcome with secondary hemorrhage has been questioned. DESIGN: Randomized, placebo-controlled, clinical trial. PARTICIPANTS: Two hundred and thirty-eight patients who had hyphema develop after blunt trauma. INTERVENTION: Eighty patients received oral tranexamic acid, 80 patients received placebo, and 78 patients received oral prednisolone. MAIN OUTCOME MEASURES: Secondary hemorrhage and vision at the time of discharge from the hospital were measured. RESULTS: Rebleeding occurred in 43 (18%) of the patients and was prevented significantly by oral tranexamic acid compared with the placebo (odds ratios [OR] = 0.39; 95% confidence interval [CI], 0.17, 0.89). Occurrence of secondary hemorrhage had weak associations with initial high intraocular pressure (OR = 2.7; 95% CI, 0.99, 7.3) and initial visual acuity of 6/60 or less (OR = 1.8; 95% CI, 0.9, 3.7). Secondary hemorrhage had no statistical association with age, gender, oral prednisolone, size of hyphema, and retinal damage. Visual acuity of 6/60 or less at the time of discharge was significantly associated with rebleeding (OR = 10.5; 95% CI, 3.7, 29.2), initial visual acuity of 6/60 or less (OR = 9.9; 95% CI, 2.8, 38.0), retinal damage (OR = 14.6; 95% CI, 3.8, 55.8), and male gender (OR = 6.5; 95% CI, 1.4, 31.9). Final visual acuity had no significant statistical association with age, use of oral prednisolone or tranexamic acid, and size of hyphema. CONCLUSIONS: High intraocular pressure and low vision at the time of first examination may be associated with increased chance of rebleeding. Retinal damage, secondary hemorrhage, male gender, and initial poor vision are associated with a worse visual outcome in patients with traumatic hyphema.     

On the estimation of Markov random field parameters

We examine the histogram method for estimating the parameters associated with a Markov random field. This method relies on the estimation of the local interaction sums from histogram data. We derive an estimator for these quantities that is optimal in a well-defined sense. Furthermore, we show that the final step of the histogram method, the solution of a least-squares problem, can be done substantially faster than one might expect if no equation culling is used. We also examine the use of weighted least-squares and see that this seems to lead to better estimates even with small amounts of data     

Polymeric nanomaterials as electrolyte and electrodes in supercapacitors

The energy challenge requires a broad range of options for energy harvesting, storage, and conversion. We have produced polymeric coatings by spraying, to be used as electrolyte and electrodes in a flexible electrochemical double layer capacitor. A thermoplastic polyurethane and a low molecular weight block copolyether were employed with LiClO₄ to prepare solid polymeric electrolytes. Carbon black (CB) and multi-walled carbon nanotubes (MWNTs) were dispersed in the polymer blend electrolyte to produce nanostructured composite electrodes. The conductivities increased with the addition of block copolyether and carbon nanotubes to the electrolyte and electrode, respectively. Scanning electron microscopy (SEM) and atomic force microscope (AFM) images of the nanocomposite electrodes showed nanoagglomerates of CB connected by carbon nanotubes. The solid supercapacitor prepared with these new materials as electrolyte and electrodes showed superior performance to other similar systems. The resulting safe and flexible multilayer device can meet the requirements of modern devices.      

Perchlorate-selective polymeric membrane electrode based on bis(dibenzoylmethanato)cobalt(II) complex as a neutral carrier

A synthesized bis(dibenzoylmethanato)Co(II) complex (Co(DBM)(2)), has been used as a ionophore for the preparation of a new perchlorate ion-selective electrode. The electrode exhibits a Nernstian response over the perchlorate concentration range of 8.0x10(-7)-1.0x10(-1)M with a slope of 60.3+/-0.5 mV per decade of concentration. The limit of detection as determined from the intersection of the extrapolated linear segments of the calibration plot is 5.6x10(-7)M. The electrode shows good selectivity towards perchlorate with respect to many common anions. The response time of the sensor is very fast (< or = 5s), and can be used for at least 2 months in the pH range of 2.0-9.0. The electrode was used to determine perchlorate in water and human urine. The interaction of the ionophore with perchlorate ions was demonstrated by UV-vis spectroscopy.     

Unveiling the Metabolic Effects of Glycomacropeptide

For many years, the main nitrogen source for patients with phenylketonuria (PKU) was phenylalanine-free amino acid supplements. Recently, casein glycomacropeptide (GMP) supplements have been prescribed due to its functional and sensorial properties. Nevertheless, many doubts still persist about the metabolic effects of GMP compared to free amino acids (fAA) and intact proteins such as casein (CAS). We endeavour to compare, in rats, the metabolic effects of different nitrogen sources. Twenty-four male Wistar rats were fed equal energy density diets plus CAS (control, n = 8), fAA (n = 8) or GMP (n = 8) for 8 weeks. Food, liquid intake and body weight were measured weekly. Blood biochemical parameters and markers of glycidic metabolism were assessed. Glucagon-like peptide-1 (GLP-1) was analysed by ELISA and immunohistochemistry. Food intake was higher in rats fed CAS compared to fAA or GMP throughout the treatment period. Fluid intake was similar between rats fed fAA and GMP. Body weight was systematically lower in rats fed fAA and GMP compared to those fed CAS, and still, from week 4 onwards, there were differences between fAA and GMP. None of the treatments appeared to induce consistent changes in glycaemia, while insulin levels were significantly higher in GMP. Likewise, the production of GLP-1 was higher in rats fed GMP when compared to fAA. Decreased urea, total protein and triglycerides were seen both in fAA and GMP related to CAS. GMP also reduced albumin and triglycerides in comparison to CAS and fAA, respectively. The chronic consumption of the diets triggers different metabolic responses which may provide clues to further study potential underlying mechanisms.     

Sorghum (Sorghum bicolor L.): Nutrients,bioactive compounds,and potential impact on human health

Sorghum is the fifth most produced cereal in the world and is a source of nutrients and bioactive compounds for the human diet. We summarize the recent findings concerning the nutrients and bioactive compounds of sorghum and its potential impact on human health, analyzing the limitations and positive points of the studies and proposing directions for future research. Sorghum is basically composed of starch, which is more slowly digested than that of other cereals, has low digestibility proteins and unsaturated lipids, and is a source of some minerals and vitamins. Furthermore, most sorghum varieties are rich in phenolic compounds, especially 3-deoxyanthocyanidins and tannins. The results obtained in vitro and in animals have shown that phenolics compounds and fat soluble compounds (polycosanols) isolated from sorghum benefit the gut microbiota and parameters related to obesity, oxidative stress, inflammation, diabetes, dyslipidemia, cancer, and hypertension. The effects of whole sorghum and its fractions on human health need to be evaluated. In conclusion, sorghum is a source of nutrients and bioactive compounds, especially 3-deoxyanthocyanidins, tannins, and polycosanols, which beneficially modulate, in vitro and in animals, parameters related to noncommunicable diseases. Studies should be conducted to evaluate the effects of different processing on protein and starch digestibility of sorghum as well as on the profile and bioavailability of its bioactive compounds, especially 3-deoxyanthocyanidins and tannins. Furthermore, the benefits resulting from the interaction of bioactive compounds in sorghum and human microbiota should be studied.