Anaerobic biodegradation of methyl tert-butyl ether under iron-reducing conditions in batch and continuous-flow cultures.

The feasibility of biodegradation of the fuel oxygenate methyl tert-butyl ether (MTBE) under iron-reducing conditions was explored in batch and continuous-flow systems. A porous pot completely-mixed reactor was seeded with diverse cultures and operated under iron-reducing conditions. For batch studies, culture from the reactor was transferred anaerobically to serum bottles containing either MTBE alone or MTBE with ethanol (EtOH) and excess electron acceptor. In the continuous-flow reactor, MTBE conversion to tert-butyl alcohol (TBA) was observed after 181 days of operation, and stable removal was achieved throughout the remainder of the study. Simultaneously, both the MTBE only and the MTBE and EtOH iron-reducing batch serum bottles also began to degrade MTBE. Bottles were respiked and the degradation rate was determined to be 2.36 +/- 0.10 x 10(-4) mmol MTBE/min-kgVSS. The EtOH present with MTBE degraded faster (7.76 +/- 0.08 x 10(-3) mmol EtOH/min-kg VSS) but did not have a noticeable effect on the rate of MTBE degradation. No evidence of TBA degradation was observed by the iron-reducing cultures. Stoichiometry of iron utilization was determined from the iron balance of the continuous-flow reactor, and it was found that the bulk of the electron acceptor was required for energy and maintenance with little remaining for cell synthesis. This is consistent with a yield coefficient of less than 0.1. Molecular analysis of the iron-reducing culture by denaturing gradient gel electrophoresis indicated that uncultured strains of delta-Proteobacteria were dominant in the reactor.     

Prenatal diagnosis of Pierre–Robin sequence as part of Stickler syndrome

Stickler syndrome or hereditary progressive arthro-ophthalmopathy, is an autosomal dominant condition characterized by ocular manifestations, arthritic changes, orofacial features and deafness, in variable degrees. We report the first case of prenatal diagnosis of Stickler syndrome in a child with a Pierre–Robin sequence (PRS) causing a polyhydramnios. When isolated polyhydramnios is not explained by immunological, metabolic or infectious causes, swallowing difficulty due to PRS must be considered. As PRS is aetiologically heterogenous, the prognosis depends on the cause. Genetic investigations and familial history must be taken into account. Here, in a context of familial Stickler syndrome, making the prenatal diagnosis of PRS as part of Stickler syndrome allowed us to reassure the parents and to anticipate airway trouble at the child's birth. Copyright © 2002 John Wiley & Sons, Ltd.     

Prenatal exclusion of homocystinuria (cystathionine β-synthase deficiency) by assay of phytohaemagglutinin-stimulated fetal lymphocytes

Homocystinuria due to cystathionine β-synthase deficiency was excluded in a fetus at 23 weeks' gestation by demonstrating activity of the enzyme in fetal lymphocytes after stimulation by phytohaemagglutinin. Fetal blood sampling was carried out because two determinations of enzyme activity on cultured amniotic cells gave low, not fully diagnostic values.     

Energy justice and ethical consumption: comparison,synthesis and lesson drawing

This paper takes a first step in comparing and synthesising the emerging concept of energy justice with extant ethical consumption literatures as two complementary theoretical approaches to ethics and consumption. To date, theories of ethical consumption and energy justice remain somewhat disconnected, so while they have some areas of potential comparability, these have not yet been fleshed out or developed. To address this lacuna, this paper explores areas where research into ethical consumption might be useful for furthering concepts of energy justice. More specifically the discussion draws on the philosophical foundations, the relationship between consumption and development, and the role of transparency and visibility in reconnecting consumption and production practices as the main areas of overlap in these literatures. The conclusion points to some lessons for emerging energy justice literatures that can be drawn from this task of comparison and synthesis.     

The application of pressure–impulse curves in a blast exceedance analysis

The magnitude of damage due to a vapor cloud explosion can be estimated in many ways, ranging from look-up tables to quantitative risk analysis. An explosion overpressure analysis is a routine part of compliance with the American Petroleum Institute (API) Recommended Practice (RP) 752 when evaluating occupied buildings in a facility that processes flammable or reactive materials. In many cases, a risk-based approach is useful because consequence modeling studies often indicate major problems for buildings at existing facilities. One of the most common risk-based methods, overpressure exceedance, incorporates a wide range of potential explosion scenarios coupled with the probability of each event to develop the probability of exceeding a given overpressure at specific locations. But this and other methods that only use overpressure may not represent an accurate building response. By combining the risk-based methodology of the exceedance analysis with pressure and impulse data in the form of pressure–impulse (P–I) curves, a better measure of building damage can be generated. P–I curves for blast loading determination have been in use for decades, and allow the user to determine levels of damage based on a predicted overpressure and its corresponding impulse. Curves have been published for entire buildings, individual structural members, window breakage, and even consequences to humans. This paper will explore application of P–I curves for building damage, and will highlight some of the benefits, as well as some of the potential problems, of using P–I curves.     

Degradation and mobility of linear alkylbenzene sulfonate and nonylphenol in sludge-amended soil

Degradation and mobility of the surfactants linear alkylbenzene sulfonate (LAS) and nonylphenol (NP) were investigated in a lysimeter study using a sandy loam soil and 45-cm soil columns. Anaerobically digested sewage sludge was incorporated in the top-15-cm soil layer to an initial content of 38 mg LAS and 0.56 mg NP kg(-1) dry wt., respectively. Spring barley (Hordeum vulgare L.) was sown onto the columns. The lysimeters were placed outdoors and therefore received natural precipitation, but were also irrigated to a total amount of water equivalent to 700 mm of precipitation. Leachate and soil samples from three soil layers were collected continuously during a growth period of 110 d. Leachate samples and soil extracts were concentrated by solid-phase extraction (SPE) and analyzed using high performance liquid chromatography (HPLC) with fluorescence detection. The concentrations in the top-15-cm soil layer declined to 25 and 45% of the initial contents for LAS and NP, respectively, within the first 10 d of the study. At the end of the study, less than 1% LAS was left, while the NP content was below the detection limit. Assuming first-order degradation kinetics, half-lives of 20 and 37 d were estimated for LAS and NP, respectively. The surfactants were not measured in leachate samples in concentrations above the analytical detection limits of 4.0 and 0.5 microg L(-1) for LAS and NP, respectively. In addition, neither LAS nor NP were measured in concentrations above the detection limits of 150 and 50 microg kg(-1) dry wt., respectively, in soil layers below the 15 cm of sludge incorporation, indicating negligible downward transport of the surfactants in the lysimeters.     

Pesticide uses and transfers in urbanised catchments

An investigation on herbicide uses in two semi-urban catchments was performed simultaneously with sampling campaigns at six stations inside both watersheds from April to July 1998. Urban uses of herbicides exceeded agricultural uses, and transfer coefficients were also higher in urban areas. Therefore, the most used product in urban areas (diuron) was by far the most contaminating product. Householders accounted for 30% of all uses. The highest measured diuron concentration in water surface was 8.7 microg l(-1) due to its use on impervious surfaces. Compared to EEC standards for drinking water production (0.1 microg l(-1)), it is clear that suburban uses of herbicides may severely endanger drinking water production from river water.     

Socioeconomic background and road traffic injuries: a study of young car drivers in Sweden

The aim of this study is to explore the manner in which different measures of original socioeconomic position (SEP) influence road traffic injuries (RTIs) among young car drivers in Sweden. The study consists of young people age 16-23. Subjects were taken from the Swedish Population and Housing Census of 1990 (n=727,995), and followed up by a search for cases of injury to car drivers in Sweden's National Hospital Discharge Register over the years 1991-96 (n=1,599). Household SEP was measured using social class, education, and disposable income. Relative risks were estimated by Poisson regression and population attributable risks were computed for each measure of SEP. Children of unskilled workers, of the self-employed, and of farmers, as well as children of parents with compulsory education only showed an increased risk of injury as car drivers compared to children in the highest socioeconomic group and children of highly educated parents. By contrast, level of household disposable income was found not to vary with RTI among young drivers. Twenty-five percent of the injuries could be avoided if all young people had the injury rate of the highest socioeconomic group, and 29% if all young people had the injury rate of those with highly educated parents. The reduction of risk differences based on household SEP calls for consideration of factors related to both differential exposure and differential susceptibility, which may be addressed in driver education.     

Prenatal diagnosis of a double heterozygote for two reciprocal translocations of familial origin

Two balanced reciprocal translocations were found in an amniotic fluid cell culture undertaken because of maternal age. One translocation had been inherited from each parent. Both translocations were traced through three generations of each family. The importance of banding techniques in diagnostic cytogenetics is stressed.