Maternal serum alpha-fetoprotein levels and fetal outcome in early second-trimester oligohydramnios

Early second-trimester oligohydramnios was associated with normal maternal serum alpha-fetoprotein (MSAFP) levels in nine out of 26 cases (35 per cent). Congenital malformations of the fetal urinary tract resulting in fetal anuria were present in nine cases; in seven of them, normal MSAFP levels were measured. In contrast, normal MSAFP levels were established in only 2 out of the 17 cases without fetal malformations. These data suggest that fetal urine is the major source of elevated AFP in the maternal compartment in early second-trimester oligohydramnios. This is further supported by the lack of any relationship between concentrations of MSAFP non-reactive with Concanavalin A, originating mainly from the yolk sacderived amniotic fluid AFP pool, and the presence of fetal diuresis. Three out of 26 women had experienced early second-trimester oligohydramnios in a previous pregnancy, suggesting the existence of a recurrence risk for this condition.     

Bio-char Sequestration in Terrestrial Ecosystems – A Review

The application of bio-char (charcoal or biomass-derived black carbon (C)) to soil is proposed as a novel approach to establish a significant, long-term, sink for atmospheric carbon dioxide in terrestrial ecosystems. Apart from positive effects in both reducing emissions and increasing the sequestration of greenhouse gases, the production of bio-char and its application to soil will deliver immediate benefits through improved soil fertility and increased crop production. Conversion of biomass C to bio-char C leads to sequestration of about 50% of the initial C compared to the low amounts retained after burning (3%) and biological decomposition (< 10–20% after 5–10 years), therefore yielding more stable soil C than burning or direct land application of biomass. This efficiency of C conversion of biomass to bio-char is highly dependent on the type of feedstock, but is not significantly affected by the pyrolysis temperature (within 350–500 ^∘C common for pyrolysis). Existing slash-and-burn systems cause significant degradation of soil and release of greenhouse gases and opportunies may exist to enhance this system by conversion to slash-and-char systems. Our global analysis revealed that up to 12% of the total anthropogenic C emissions by land use change (0.21 Pg C) can be off-set annually in soil, if slash-and-burn is replaced by slash-and-char. Agricultural and forestry wastes such as forest residues, mill residues, field crop residues, or urban wastes add a conservatively estimated 0.16 Pg C yr⁻¹. Biofuel production using modern biomass can produce a bio-char by-product through pyrolysis which results in 30.6 kg C sequestration for each GJ of energy produced. Using published projections of the use of renewable fuels in the year 2100, bio-char sequestration could amount to 5.5–9.5 Pg C yr⁻¹ if this demand for energy was met through pyrolysis, which would exceed current emissions from fossil fuels (5.4 Pg C yr⁻¹). Bio-char soil management systems can deliver tradable C emissions reduction, and C sequestered is easily accountable, and verifiable.     

Bioconcentration of n-dodecane and its highly branched isomer 2,2,4,6,6-pentamethylheptane in fathead minnows

Petroleum products are complex mixtures of hydrocarbons. They are important as constituents of fuels and lubricants, and as key raw materials for the chemicals industry. Since there is a potential for accidental releases to the aquatic environment, bioaccumulation of higher hydrocarbons is of concern. Here, the bioconcentration behaviour of two representative hydrocarbons, the dodecane isomers n-dodecane and 2,2,4,6,6-pentamethylheptane (PMH), was investigated in fathead minnows at concentrations in water below their maximum aqueous solubility. The concentration of n-dodecane in fish did not exceed our method limit of detection of 60 μg/kg. In contrast, PMH could be quantified in fish. No significant increase in the ratio of PMH concentrations in fish to water could be detected indicating that an exposure time of 4–10 days is sufficient to approach steady-state. For n-dodecane the upper limit of the bioconcentration factor (BCF) is estimated by dividing the method limit of detection by the exposure concentration and a value of 240 l/kg is derived. For PMH the bioconcentration factor, estimated as the average fish/water concentration ratio during the steady-state part of the experiment, ranges between 880 and 3500 l/kg. The BCFs of both compounds are small compared to their hydrophobicity. Given that both linear and branched hydrocarbons are known to be biotransformed by fish, it appears that efficient metabolism of the test compounds in fathead minnows prevents bioaccumulation.     

Determination of mono-, di- and trinitronaphthalenes in soil samples contaminated by explosives

We investigated the extraction of eight mono-, di- and trinitronaphthalenes from soil samples by ultrasonic, respectively, soxhlet extraction. Sonication was the more convenient procedure with a usually higher repeatability than the soxhlet method. All extracts were analysed by high-performance liquid chromatography with diode array detection. These methods were used to determine the concentration of nitronaphthalenes in five soil samples polluted by explosives. The most abundant contaminants were 1,5- and 1,8-dinitronaphthalene as well as 1,3,5-, 1,3,8- and 1,4,5-trinitronaphthalene. In all samples the sum of trinitronaphthalenes exceeded the sum of mono- and dinitronaphthalenes. It is recommendable to include these eight compounds in the analytical exploration of sites contaminated by explosives.     

Calculation of bioconcentration factors from kinetic data by non-linear iterative least-squares regression analysis using a programmable minicalculator

A program to fit theoretically modelled uptake and clearance periods of the bioconcentration of chemicals to experimental data using a programmable pocket calculator with thermal printer is reported. The bioconcentration factor (BCF) is calculated from the ratio of uptake and clearance rate constants. Because of the impossibility to linearize the kinetic equations an iterative nonlinear GAUSS-NEWTON least-squares fit has been applied for the pocket calculator programm ACCUTI-59, which calculates from a set of start parameters the best values for uptake and clearance rate constants, BCF, and the standard errors as well as the sum of squared deviations. A listing of the program is given.     

Comparison of the flower scent of the sexually deceptive orchid <Emphasis Type="Italic">Ophrys iricolor</Emphasis> and the female sex pheromone of its pollinator <Emphasis Type="Italic">Andrena morio</Emphasis>

Summary. Ophrys flowers mimic the female produced sex pheromone of their pollinator species to attract males for pollination. The males try to copulate with the putative female and thereby pollinate the flower. Using electrophysiological and chemical analyses, floral volatiles released by O. iricolor as well as the female sex pheromone of its pollinator species, Andrena morio are investigated. Overall, 38 peaks comprising 41 chemical compounds, were found to release reactions in the antennae of male A. morio bees. Analyses using coupled gas chromatography-mass spectrometry revealed the presence of alkanes and alkenes with 20 to 29 carbon atoms, aldehydes (C9 to C24) and two esters. Almost all of those compounds were found in similar proportions in both, the floral extracts of O. iricolor and cuticle surface extracts of A. morio females. The pattern of biologically active volatiles described here is very similar to that used by other Ophrys species pollinated by Andrena males.