Ozonation of metoprolol in aqueous solution: ozonation by-products and mechanisms of degradation

This study investigated the degradation pathway of metoprolol, a widely used β-blocker, in the ozonation via the identification of generated ozonation by-products (OPs). Structure elucidation of OPs was performed using HPLC coupled with quadrupole time-of-flight high-resolution mass spectrometry. Seven OPs were identified, and four of these have not been reported elsewhere. Identified OPs of metoprolol included aromatic ring breakdown by-products; aliphatic chain degraded by-products and aromatic ring mono-, di-, and tetrahydroxylated derivatives. Based on the detected OPs, metoprolol could be degraded through aromatic ring opening reaction via reaction with ozone (O₃) and degradation of aliphatic chain and aromatic ring via reaction with hydroxyl radical (?OH).     

Embryonic and fetal globins are expressed in adult erythroid progenitor cells and in erythroid cell cultures

The understanding of human hemoglobin ontogeny during development is of biological and clinical importance. Molecular and immunocytological techniques were used to study the expression of embryonic zeta (ζ), epsilon (ε), and fetal gamma (γ) globin genes in newborn cord blood, peripheral blood from men, pregnant and non-pregnant women, and in vitro mononuclear cell cultures. We have shown that embryonic and fetal globin mRNA and peptides are expressed in cultured erythroid cells and in circulating blood cells from newborns, adult non-pregnant women and from men. The findings suggest that during erythroid cell differentiation in newborns and adults, there is a transient recapitulation of sequential globin chain expression as found during embryonic and fetal development. Furthermore, these findings underscore the need for caution in using embryonic and fetal globin chains as markers to identify erythroid cells of fetal origin in maternal circulation for prenatal diagnosis. Copyright © 2001 John Wiley & Sons, Ltd.     

The effect of fetal gender on nuchal translucency at 10–14 weeks of gestation

Recent data have suggested that fetal nuchal translucency (NT) is affected by fetal gender. We investigated the size of this effect in 12 189 unselected pregnancies with known normal outcomes that had undergone NT measurements between 10 and 14 weeks of gestation. NT increased with gestation and was converted to multiples of the median (MoM) for the gestational day. The median NT MoM (95% CI) for female fetuses was 0.98 (0.97–0.99). This was significantly lower than that of the male fetuses (1.03; range1.02–1.04) (p<0.0005; Wilcoxon rank-sum test). The gender difference was not observed at 10 weeks but was observed from 11 weeks onwards. There is no obvious explanation for the above findings. Copyright © 2001 John Wiley & Sons, Ltd.     

Kinetic studies of the degradation of parabens in aqueous solution by ozone oxidation

Ozone degradation of a mixture containing methylparaben, ethylparaben, propylparaben, butylparaben and benzylparaben was carried out in aqueous solution. The degradation followed the pseudo-first-order kinetic model and occurs with two ozonation stages with the observed rate constants of second stage ozonation, k _obs2, being higher than the observed rate constants in first stage, k _obs1. The k _obs1 of parabens was found to increase exponentially whilst k _obs2 was found to maximize at 35°C. Both k _obs1 and k _obs2 were found to decrease exponentially with respect to the initial concentration of parabens. Both pH and ozone dose showed positive effects on the rate of degradation. It was also observed that an ozone dose of 0.67 g/h resulted in the removal of 99% of parabens in 12 min, and also the removal of 61 and 32% of chemical oxygen demand (COD) and total organic carbon (TOC), respectively, in 3 h of ozonation time for a 500 μM of solution of parabens.     

Contamination time effect on lead and cadmium fractionation in a tropical coastal clay

The capability of a tropical coastal clay to immobilize lead (Pb) and cadmium (Cd) was investigated in laboratory batch sorption tests conducted under acidic, neutral, and slightly alkaline conditions. The contact time was extended to 65 d. The distribution of Pb and Cd among various sorbed phases was examined using a sequential extraction technique. The sorbed phases were fractionated into the exchangeable, carbonate, reducible, organic, and residual fractions. There were only small changes in the total Pb and Cd sorption beyond a 1-d sorption period. The metal fractionation results show that the amount of Pb and Cd in various fractions changed with sorption time, and the changes were pH-dependent. These changes could be attributed to mineral dissolution and transformation or redistribution of the sorbed phases. Transformation of the sorbed phases resulted in increasing Pb and Cd retention in the more persistent fractions with time, at the expense of reductions in the loosely bound fractions. Nevertheless, Pb and Cd fractionation in the solid phase appeared to reach equilibrium within the 65-d sorption period. These Pb and Cd fractionation results reflect the effect of contamination time on the heavy metal lability and bioavailability in the subsurface environment.     

Fenton oxidation of 2,4- and 2,6-dinitrotoluene and acetone inhibition

The performances and kinetic parameters of Fenton oxidation of 2,4- and 2,6-dinitrotoluene (DNT) in water-acetone mixtures and explosive contaminated soil washing-out solutions were investigated at a laboratory scale. The experimental results show that acetone can be a significant hydroxyl radical scavenger and result in serious inhibition of Fenton oxidation of 2,4- and 2,6-DNT. Although no serious inhibition was found in contaminated soil washing-out solutions, longer reaction time was needed to remove 2,4- and 2,6-DNT completely, mainly due to the competition of hydroxyl radicals. Fenton oxidation of 2,4- and 2,6-DNT fit well with the first-order kinetics and the presence of acetone also reduced DNT’s degradation kinetics. Based on the comparison and matching of retention time and ultraviolet (UV) spectra between high performance liquid chromatography (HPLC) and standards, the following reaction pathway for 2,4-DNT primary degradation was proposed: 2,4-DNT → 2,4-dinitro-benzaldehyde → 2,4-dinitrobenzoic acid → 1,3-dinitrobenzene → 3-nitrophenol.     

Solubilization of water-insoluble beta-glucan isolated from Ganoderma lucidum

The fungal beta-D-glucan is a biological response modifier (BRM), but a major obstacle to the clinical utilization of beta-glucan BRMs is thei relative lack of solubility in aqueous media. Water insoluble fungal glucans extracted by alkali from the mycelia of Ganoderma lucidum were sulfated to yield their corresponding water-soluble derivatives. Insoluble glucan is dissolved in methyl sulfoxide and urea, and is partially sulfated with sulfuric acid. The sulfated glucan (SGL) yield prepared from insoluble glucan (IGL) was 85%, the sulfation degree of SGL was about 14.9%, and the solubility of SGL was above 95% in water. The monosugar SGL content was 34.9% alpha-glucose and 35.9% beta-glucose. The mean molecular weight (MW) of SGL was shown as a single peak on Sepharose CL-4B column chromatography, and their MW was approximately 9.3 kDa. The 13C NMR spectrum analysis shows that SGL has a high similarity with the beta-(1-->3)-linked triple-helical control.     

Desorption characteristics of kaolin clay contaminated with zinc from electrokinetic soil processing

A number of bench scale laboratory column tests were carried out using a newly designed and developed electrokinetic cell to investigate the fundamental behavior of zinc-spiked kaolin clay subjected to an electric field. Laboratory investigations focused on (i) zinc migration by the combined effects of electromigration and electro-osmosis and (ii) the electrically induced desorption characteristics of zinc-contaminated kaolin that occurred during processing. The correlations of the applied voltage gradient, electro-osmotic flow rate, and the development of a pH gradient were examined and evaluated. The results showed that the removal efficiency was high during the early stage of processing due to rapid desorption by electrokinetic effects in the cathode region. However, the majority of zinc migrating from the anode was precipitated due to the high pH environment in the cathode region.     

Influence of pedestrian age and gender on spatial and temporal distribution of pedestrian crashes

Objectives: Every year, about 1.24 million people are killed in traffic crashes worldwide and more than 22% of these deaths are pedestrians. Therefore, pedestrian safety has become a significant traffic safety issue worldwide. In order to develop effective and targeted safety programs, the location- and time-specific influences on vehicle–pedestrian crashes must be assessed. The main purpose of this research is to explore the influence of pedestrian age and gender on the temporal and spatial distribution of vehicle–pedestrian crashes to identify the hotspots and hot times.

Methods: Data for all vehicle–pedestrian crashes on public roadways in the Melbourne metropolitan area from 2004 to 2013 are used in this research. Spatial autocorrelation is applied in examining the vehicle–pedestrian crashes in geographic information systems (GIS) to identify any dependency between time and location of these crashes. Spider plots and kernel density estimation (KDE) are then used to determine the temporal and spatial patterns of vehicle–pedestrian crashes for different age groups and genders.

Results: Temporal analysis shows that pedestrian age has a significant influence on the temporal distribution of vehicle–pedestrian crashes. Furthermore, men and women have different crash patterns. In addition, results of the spatial analysis shows that areas with high risk of vehicle–pedestrian crashes can vary during different times of the day for different age groups and genders. For example, for those between ages 18 and 65, most vehicle–pedestrian crashes occur in the central business district (CBD) during the day, but between 7:00 p.m. and 6:00 a.m., crashes among this age group occur mostly around hotels, clubs, and bars.

Conclusions: This research reveals that temporal and spatial distributions of vehicle–pedestrian crashes vary for different pedestrian age groups and genders. Therefore, specific safety measures should be in place during high crash times at different locations for different age groups and genders to increase the effectiveness of the countermeasures in preventing and reducing vehicle–pedestrian crashes.