Maternal serum leptin concentration during the second trimester of pregnancy: association with fetal chromosomal abnormalities

Recent studies suggest that leptin, the product of the obese gene, is produced by the placenta during pregnancy. The present study addressed the question whether second trimester maternal serum leptin could be altered by fetal Down syndrome or Edwards syndrome. Maternal serum leptin concentrations were measured in 18 pregnancies complicated with Down syndrome, six pregnancies complicated with Edwards syndrome and 183 uncomplicated pregnancies during the second trimester of pregnancy. The present results demonstrate that leptin concentrations in uncomplicated pregnancies slightly decrease from the 16th week of pregnancy, reaching a minimum of 18.8 ng/ml around the 20th week, and then rapidly increase to 28.2 ng/ml by the 24th week. Leptin correlation with maternal body weight decreases from r=0.695 at 16–17 week of gestation to r=0.544 at >22 weeks of gestation. There was no significant difference between the mean MoMs of Down syndrome- (0.926) or Edwards syndrome- (0.960) affected pregnancies and normal pregnancies (1.002). A weak correlation (r=0.18, p<0.02) was observed between corrected leptin MoMs and human chorionic gonadotrophin (hCG) MoMs in normal pregnancies. It is assumed that around the 20th week of pregnancy placental leptin production is activated or at least is accelerated and it is added to the amount of leptin produced by maternal adipose tissue. Fetal Down syndrome or Edwards syndrome does not seem to alter maternal leptin concentration and therefore leptin cannot be used as a marker for these chromosomal abnormalities in the early second trimester of pregnancy. Copyright © 2002 John Wiley & Sons, Ltd.     

Estimating net changes in life-cycle emissions from adoption of emerging civil infrastructure technologies

There is a net emissions change when adopting new materials for use in civil infrastructure design. To evaluate the total net emissions change, one must consider changes in manufacture and associated life-cycle emissions, as well as changes in the quantity of material required. In addition, in principle one should also consider any differences in costs of the two designs because cost savings can be applied to other economic activities with associated environmental impacts. In this paper, a method is presented that combines these considerations to permit an evaluation of the net change in emissions when considering the adoption of emerging technologies/materials for civil infrastructure. The method factors in data on differences between a standard and new material for civil infrastructure, material requirements as specified in designs using both materials, and price information. The life-cycle assessment approach known as economic input-output life-cycle assessment (EIO-LCA) is utilized. A brief background on EIO-LCA is provided because its use is central to the method. The methodology is demonstrated with analysis of a switch from carbon steel to high-performance steel in military bridge design. The results are compared with a simplistic analysis that accounts for the weight reduction afforded by use of the high-performance steel but assuming no differences in manufacture.     

Investigation of the self-cleaning ability of Lake Koumoundourou near Athens from oil pollution

This study was performed under a general project for the restoration of Lake Koumoudourou. This lake is situated next to the sea in the prefecture of Attica, with a large oil refinery installation and a military fuel depot nearby. The geological formations of the surrounding area are quaternary alluvial deposits and fans, which overlie karstic limestone and dolomites of the Middle Tertiary to Lower Jurassic. This lake has been polluted by oil spills and leaks from both the refinery and the military depot, containing large amounts of different petroleum extracts. In addition, the aquifer has also been polluted by an underground pipe connecting these two installations as well as by percolated surface pollutants and leaks from the refinery tanks. The purpose of the experimental investigation was to determine the way to clean up the bottom of the lake and keep the water under European Union directive standards for bathing waters. To accomplish the target, a purpose built aquarium was constructed in the laboratory. Mud, water, algae, and fish were transported from the lake, and the investigation began after a 6-day period necessary for the aquarium to adjust. The simulation proved successful and the experiment resulted in 50% reduction of oil and chemical oxygen demand.     

Investigation of the self-cleaning ability of Lake Koumoundourou near Athens from oil pollution

The highly permeable sand and gravel of the Little Miami River Valley Aquifer System near Milford, Ohio provide the community with a high-yielding source of drinking water. While this hydrogeologic setting is ideal from a water quantity standpoint, it is greatly vulnerable to contamination. The future viability of the wellfield came into question when it was discovered that the wellfield was contaminated with volatile organic contaminants, leaving the City with the costly cleanup. Milford's perseverance is also challenged by having to deal with a deteriorating treatment plant. Furthermore, larger water suppliers in the area have threatened the community's independence. The question facing this community, and many other smaller communities, was whether to surrender its independence or invest in their future. The city has decided to keep their wellfield and to conduct a groundwater study. The objectives of the study were to: (a) collect and evaluate hydrogeological data; (b) develop a conceptual model of the groundwater system; (c) construct groundwater flow and geochemical models; (d) delineate wellhead protection area; and (e) develop a comprehensive management program. Collected hydrogeologic data served as a basis for the conceptual model. The U.S. Geological Survey (USGS) three-dimensional groundwater flow model MODFLOW was used in conjunction with MODPATH, a particle-tracking program, to identify travel times and paths of contaminants. This approach ultimately lead to the delineation of the wellhead protection area (WHPA). Geochemical mixing models were constructed using the USGS PHREEQC to verify the flow model results. The use of both flow and geochemical models to delineate the WHPA and to manage groundwater resources is a unique approach. The modeling results provide the City of Milford a management tool in making difficult policy decisions regarding future land use, siting for new monitoring and production wells, and identification of potential pollution sources.