Perfluorinated acids in Arctic snow: new evidence for atmospheric formation

Perfluorinated acids (PFAs) are ubiquitously found in water and biota, including remote regions such as the High Arctic. Under environmental conditions, PFAs exist mainly as anions and are not expected to be subject to long-range atmospheric transport in the gas phase. Fluorinated telomer alcohols (FTOHs) are volatile and can be atmospherically oxidized to form perfluorocarboxylic acids. Analogously, fluorosulfamido alcohols can be oxidized to form perfluorooctane sulfonate (PFOS). High Arctic ice caps experience contamination solely from atmospheric sources. By examining concentrations of PFAs in ice cap samples, it is possible to determine atmospheric fluxes to the Arctic. Ice samples were collected from high Arctic ice caps in the spring of 2005 and 2006. Samples were concentrated using solid-phase extraction and analyzed by LC-MS-MS. PFAs were observed in all samples, dating from 1996 to 2005. Concentrations were in the low-mid pg L(-1) range and exhibited seasonality, with maximum concentrations in the spring-summer. The presence of perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnA) on the ice cap was indicative of atmospheric oxidation as a source. Ratios of PFAs to sodium concentrations were highly variable, signifying PFA concentrations on the ice cap were unrelated to marine chemistry. Fluxes of the PFAs were estimated to the area north of 65 degrees N for the 2005 season, which ranged from 114 to 587 kg year(-1) for perfluorooctanoic acid (PFOA), 73 to 860 kg year(-1) for perfluorononanoic acid (PFNA), 16 to 84 kg year(-1) for PFDA, 26 to 62 kg year(-1) for PFUnA, and 18 to 48 kg year(-1) for PFOS. The PFOA and PFNA fluxes agreed with FTOH modeling estimations. A decrease in PFOS concentrations through time was observed, suggesting a fast response to changes in production. These data suggest that atmospheric oxidation of volatile precursors is a primary source of PFAs to the Arctic.     

A rotating disk of gas and dust around a young counterpart to beta Pictoris

beta Pictoris is the best known example of a main-sequence star encircled by a tenuous disk. Optical and infrared images of beta Pic suggest that the disk is composed of dust grains which have been interpreted as the debris generated by the disruption of the asteroid-sized remnants of planet-formation processes. The star itself is relatively old, with an age in excess of 100 Myr. Here we present high-resolution millimetre-wave images of continuum and molecular-line emission from dust and gas surrounding a much younger star, MWC480: the stellar properties of MWC480 are similar to those of beta Pic, but its age is just 6Myr. The morphology of the circumstellar material and a comparison with the predictions of kinematic modelling indicate the presence of a rotating disk, gravitationally bound to the star. Moreover, the mass of the disk is greater than the minimum required to form a planetary system like our own. We therefore suggest that the disk around the young star MWC480 could be a progenitor of debris disks of the type associated with older stars such as beta Pic, and so holds much promise for the study of both the origin of debris disks and the early stages of the formation of planetary systems.     

Puncture resistance of polyester (PET) and polypropylene (PP) needle-punched nonwoven geotextiles

It is common practice to use needle-punched nonwoven geotextiles as puncture protection for geomembranes against sharp objects like gravel or stones in either the soil above or the underlying soil/rock below. There are several design and experimental methods available for geotextile selection in this regard. None, however, directly address the type of resin or fiber from which the geotextile is made. This paper does exactly that insofar as a direct comparison of similar mass per unit area polyester (PET) versus polypropylene (PP) geotextiles are concerned. Furthermore, two types of PP geotextiles are evaluated; one made from continuous filaments and the other from staple fibers. Three different size and shaped puncture probes are used in the testing program. All three are ASTM Standards, i.e., D4833, D5495 and D6241.The test results clearly indicate that geotextiles made from PP fibers outperform those made from PET fibers at all masses evaluated. Clearly, the present trend of using PP resin for heavy nonwoven protection geotextiles seems justified on the basis of these test results. In addition, the continuous filament PP and staple fiber PP geotextiles performed equivalently over all mass ranges for the three different types of puncture tests.     

The specific hospital significantly affects red cell and component transfusion practice in coronary artery bypass graft surgery: a study of five hospitals

BACKGROUND: Interhospital differences in blood transfusion practice during coronary artery bypass graft (CABG) surgery have been noted, but the underlying issues have not been identified. STUDY DESIGN AND METHODS: Records of 3217 consecutive CABG cases in five university teaching hospitals in 1992 and 1993 were stratified by hospital, type of revascularization conduit, patients' sex, and other factors. Statistical methods were used to compare patient characteristics, transfusion outcomes, and hospital outcomes. RESULTS: Forward two-step logistic regression using patient likelihood of red cell transfusion factors in the first step and the specific hospital in the second step revealed a significant effect of hospital on the delta odds ratios for red cell transfusion. This finding was confirmed by analyses of a highly stratified subset of cases, males in diagnosis-related group 107 (primary cases of coronary bypass without coronary catheterization) who underwent revascularization with venous and internal mammary artery grafts, revealing variations among hospitals from 109 to 457 units of red cells transfused per hundred cases. Corresponding variations in transfusions of all blood components were from 324 to 1019 units by hospital. Variation in red cell transfusion practice among surgeons in the same hospital was not responsible for these interhospital differences. CONCLUSION: The effect of the specific hospital on transfusion practice is attributed to institutional differences that, through reasons of training or hierarchy, become ingrained in hospitals.     

Cure kinetics of the cardanyl acrylate–styrene system using isothermal differential scanning calorimetry

The curing kinetics of styrene (30 wt %) and cardanyl acrylate (70 wt %), which was synthesized from cardanol and acryloyl chloride, was investigated by differential scanning calorimetry under isothermal condition. The method allows determination of the most suitable kinetic model and corresponding parameters. All kinetic parameters including the reaction order, activation energy E_a and kinetic rate constant were evaluated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2034–2039, 2002     

Das Verhältnis der Stabilisotopen18O und16O zur Beurteilung von Auslandswein

The relation of the stabile isotopes¹⁸O/¹⁶O was determined as deviation from an internationally accepted standard (Delta-value in per mil.; standard SMOW) with SIRA in 359 wines of Tunis, Portugal, Greece, Italy, Spain and Hungary. The determined relation is primary influenced by the geografical latitude of the wine region. The influence of the year and the climatic effect of certain areas increases from the south to the north. The results of individual climatical homogeneous areas are combined. They can serve as provisional base of knowledge in order to indicate the addition of water and false declarations of the origin of wines. Furthermore, information is given about the Delta-values of the ground-water of different regions, which are completely negative. Examples were given how to quantify the addition of water by using the Delta-values of authentic wines and ground-water. Some examples for falsification of wines are described. What ist further needed for using the¹⁸O/¹⁶O-ratio in the routine analysis of wines is discussed.     

Shiga toxin binds human platelets via globotriaosylceramide (Pk antigen) and a novel platelet glycosphingolipid

Hemolytic-uremic syndrome is a clinical syndrome characterized by acute renal failure, microangiopathic hemolytic anemia, and thrombocytopenia that often follows infection by Shiga toxin- or verotoxin-producing strains of Escherichia coli. Because thrombocytopenia and platelet activation are hallmark features of hemolytic-uremic syndrome, we examined the ability of Shiga toxin to bind platelets by flow cytometry and high-performance thin-layer chromatography (HPTLC) of isolated platelet glycosphingolipids. By HPTLC, Shiga toxin was shown to bind globotriaosylceramide (Gb3) and a minor platelet glycolipid with an Rf of 0.03, band 0.03. In a survey of 20 human tissues, band 0.03 was identified only in platelets. In individuals, band 0.03 was expressed by 20% of donors and was specifically associated with increased platelet Gb3 expression. Based on glycosidase digestion and epitope mapping, band 0.03 was hypothesized to represent a novel glycosphingolipid, IV3-beta-Galalpha1-4galactosylglobotetraosylceramide. Based on incidence, structure, and association with increased Gb3 expression, band 0.03 may represent the antithetical Luke blood group antigen. By flow cytometry, Shiga toxin bound human platelets, although the amount of Shiga toxin bound varied in donors. Differences in Shiga toxin binding to platelet membranes did not reflect differences in platelet Gb3 expression. In contrast, there was a loose association between Shiga toxin binding and decreasing forward scatter, suggesting that Shiga toxin and verotoxins bind more efficiently to smaller, older platelets. In summary, Shiga and Shiga-like toxins may bind platelets via specific glycosphingolipid receptors. Such binding may contribute to the thrombocytopenia, platelet activation, and microthrombus formation observed in hemolytic-uremic syndrome.     

Hemodynamic follow-up of cardiac allografts from poisoned donors

BACKGROUND: The current shortage of donor organs, combined with an increasing demand for cardiac allografts, means that extended donor criteria are becoming more and more accepted. The use of cardiac allografts for transplantation from donors after acute poisoning is still under discussion; few data are currently available in the medical literature. We describe our experience with 19 orthotopic heart transplant recipients of organs from donors after acute intoxication with different agents. METHODS: Between March 1989 and December 1997, 883 orthotopic heart transplantations were performed at our transplant unit. Within this group, we accepted donor hearts after ethanol intoxication (n=1), benzodiazepine (n=1), alkylphosphate (E 605) in combination with beta-blocker intoxication (n=1), carbon monoxide poisoning (n=5), digitalis (n=1), digitalis/glibenclamide (n=1), chlormethiazole (n=1), propoxyphene (n=1), alkylphosphate (E 605) (n=1), insulin (n=2), neprobamate/ thiocyacide/flurazepam (n=1), paracetamol (n=1), carbamazepine (n=1), and cyanide (n=1) intoxication. At the time of organ explantation, hemodynamic data were available from all patients. RESULTS: Early mortality in this group was 11%; cumulative survival after 5 years was 74%. CONCLUSIONS: Based on our limited experience, cardiac allografts from donors exposed to different kinds of poisons can be transplanted in selected cases. If the donor organ is not hemodynamically compromised, showing regular filling pressures on low or mild inotropic support just before explantation, and if there are no electrocardiographic changes in combination with elevation of the transaminases, cardiac allograft transplantation seems to be a safe and life-saving procedure.     

The influence of vadose zone conditions on groundwater pollution: Part I: Basic principles and static conditions

The significance of the vadose soil zone (i.e., above a water table) is of the utmost importance in groundwater pollution problems. Much of this zone is unsaturated, such that fluid movement and contaminant attenuation conditions are favorable for mitigation of aquifer pollution. In this paper, the basic principles of moisture retention and the implications for leachate control are described in a state-of-the-art format.To illustrate the use of these concepts six generalized examples are presented. They cover a wide range of practical situations, including:? vadose zone storage? land treatment of wastewater and sludges? waste dewatering? hydrocarbon spill storage? capillary break situations? air and water drainage under linersSince this paper treats only the static condition, a companion paper will be offered shortly dealing with leachate flow and seepage in a wide range of applications.