Haloacetates in fog and rain

Atmospheric haloacetates can arise from photochemical degradation of halogenated hydrocarbons and from direct anthropogenic emissions. Furthermore, there is also evidence of natural sources although these are quantitatively uncertain. As haloacetates are highly soluble in water, hydrometeors are most significant for their deposition. Fogwater (96 samples) and rainwater samples (over 100 samples) were collected from July 1998 to March 1999 at an ecological research site in northeastern Bavaria, Germany. They were analyzed for monofluoroacetate (MFA), difluoroacetate (DFA), trifluoroacetate (TFA), monochloroacetate (MCA), dichloroacetate (DCA), trichloroacetate (TCA), monobromoacetate (MBA), and dibromoacetate (DBA). The major inorganic ions were also determined. High concentrations of up to 11 microg/L MCA, 5 microg/L DCA, 2 microg/L TCA, and 2 microg/L TFA were found in fogwater associated with westerly winds. Backward trajectories were calculated to determine the origin of the air masses. MBA and DBA have highest concentrations in fogwater advected with air originating from the Atlantic, suggesting the marine origin of these two compounds. All analyzed substances show higher average concentrations in fog than in rain. Estimates of the deposition of haloacetates suggest that the contribution of fog may be more important than rain for the total burden of a forest ecosystem.

Postoperative suction drainage of the axilla: for how long? Prospective randomised trial

OBJECTIVE

To define the correct time to remove the drain after axillary dissection for carcinoma of the breast.

DESIGN

Prospective randomised trial.

SETTING

Two public hospitals, Israel.

SUBJECTS

90 women who required axillary dissection for carcinoma of the breast.

INTERVENTIONS

42 were randomised to have the drain removed on postoperative day 3, and 48 to keep the drain in until discharge had decreased to less than 35 ml/24 hours.

MAIN OUTCOME MEASURES

Formation of seromas or wound infections, need to reinsert the drain, and duration of hospital stay.

RESULTS

Early removal of the axillary drain was associated with a significantly higher incidence of seromas (9/42 compared with 2/48, p = 0.02) unless the total amount of fluid drained during the first three postoperative days was less than 250 ml.

CONCLUSION

Drains should be removed after axillary dissection only when the daily amount of fluid discharged is low, unless the drainage during the first three days is less than 250 ml.

Trends of air pollution in the Fichtelgebirge Mountains, Bavaria

We analyzed 13 years of hourly measurements of SO(2), NO(x), and O(3), at forest ecosystem research sites in SE Germany. A quasi-continuous data record was obtained by combining data sets from two locations. Before interpreting trends in the combined data set, we analyzed if the change of location introduced a systematic bias. We employed autocorrelation functions, Hurst statistics, complexity analysis, and recurrence quantification and found that the partial data sets exhibited no indication of the presence of any bias. For SO(2), we also compared the data from the forest sites with data obtained in nearby cities and also found no indications for any systematic effects. Applying nonparametric trend statistics we found a significant decrease of the SO(2). Most of the observed decrease is due to the reductions of SO(2) emissions in eastern Germany, but reductions in western Germany and the Czech Republic also played important roles. For O(3), we observed a significant increase, the causes of which are unclear from our data alone. No trend was identified for NO(x).

Urban emissions measured with aircraft

Detailed knowledge of the quantity and composition of urban emissions is a prerequisite for successful application of atmospheric models to predict transport and distribution of primary and secondary air pollutants in the troposphere. We investigate the prospects and limitations of aircraft measurements in the determination of emission fluxes from urban areas. Our analysis focuses on data collected in September 1994 in and around Athens, Greece. Generally, emission fluxes from cities can be quantified with aircraft and with the minimum acceptable precision (uncertainty better than a factor of 2) only under very favorable meteorological conditions, namely in a homogeneous flow field in a well-mixed boundary layer. Better accuracy can be achieved only through ensemble averaging of repeated measurements. From our measurements in the Athens area, we deduced relative emission ratios of pollutant gases. With the support of ground-based measurements in a street canyon, the emission ratios NOx/CO, SO2/CO, and volatile organic compounds/CO (34 individual VOCs) could be determined with high precision. These results are very useful in analyzing differences between various existing emission inventories. Our data for VOCs reveal that the non-traffic emissions are of the same magnitude as the emissions originating from traffic.

The effect of heat load and dehydration on hypertonic saline solution treatment of uncontrolled hemorrhagic shock

Hypertonic saline solution treatment of uncontrolled hemorrhagic shock (UCHS) leads to increased bleeding from injured vessels, fall in arterial blood pressure, and increased mortality. The effect of dehydration induced by either water deprivation or heating on this response was studied in rats. The animals were divided into four groups: group 1 (n = 32), normal rats; group 2 (n = 30), water deprivation for 12 hours; group 3 (n = 30), heating at 37 degrees C for 5 hours; and group 4 (n = 30), heating as in group 3 and water deprivation as in group 2. UCHS was induced in all rats by 20% resection of the animals' tail. The rats were then divided into four treatment subgroups: group a was untreated, group b was treated after 15 minutes with 5 mL/kg NaCl 7.5% hypertonic saline (HTS), group c was treated after 15 minutes with 41.5 mL/kg NaCl 0.9% large volume normal saline (LNS) and group d was treated after 15 minutes with HTS + LNS. Tail resection in group 1a resulted in bleeding of 4.9 +/- 0.3 mL, and fall in mean arterial pressure (MAP) to 50 +/- 3 mm Hg (p < 0.001). Blood loss and fall in hematocrit in groups 2, 3, and 4 was significantly lower than in group 1. The fall in MAP and pulse rate was similar in all four groups.(ABSTRACT TRUNCATED AT 250 WORDS)