A preliminary analysis of aortic injuries in lateral impacts

Injuries to the aorta are among the more serious injuries that result from vehicle impacts, and often may be fatal. This article examines the incidence of aortic injuries in the United States and United Kingdom by using two international databases of real-world crashes. The main outcome of interest was the level of risk associated with each principal direction of force for drivers and front-seat passengers with respect to sustaining aortic injuries. The results indicate that the risk of sustaining an injury to the aorta is greater for near-side crashes than for far-side crashes. Further it is apparent that, given a near-side crash, the risk of an aortic injury is greater on the left side of the body (and left side of the vehicle) than on the right. It also was found that the delta-V of crashes where occupants sustained an injury to the aorta was considerably higher than crashes where occupants did not sustain aortic injuries. It is speculated that the anatomical asymmetry of the thorax might play a role in the differences seen in injury risk associated with different impact directions. The results presented in this article could be of use to both the emergency physician treating patients involved in motor vehicle collisions as well as the engineer involved in occupant design countermeasures. Limitations and further planned research are discussed.     

The Impact of Conifer Harvesting on Stream Water Quality: A Case Study in Mid-Wales

A 12-year record of water quality data for runoff from a spruce forested hillslope with podzolic soils shows the impacts of conifer harvesting and replanting in relation to nitrate generation and its influence on surface water acidification. With felling, nitrate increases from a background of 18 Eq/l to about 50 Eq/l after 1 to 2 years and then declines to background levels over the next 1 to 2 years and to lower concentrations thereafter. This change is mirrored by an acidification process as manifest by a change in Gran alkalinity, acid neutralization capacity (ANC) and aluminium concentrations as well as pH. For example, Gran alkalinity and ANC, which start at negative concentrations prior to felling (about –20 and –50 Eq/l, respectively), become more negative (–30 and –100 Eq/l, respectively) at high nitrate concentrations. Correspondingly, pH decreases from about 4.7 to 4.5 and aluminium concentrations increase from about 14 to 16 M. Subsequently, the acidification is reversed as nitrate concentrations decline and after five years post-felling the system has higher pH, Gran alkalinity and ANC together with lower aluminium concentrations than even before the felling took place (the post-felling values are about 4.9, -15 Eq/l, –20 Eq/l and 7 M/l, respectively).Other determinands show clear changes over time. For example, there is a marked increase in sodium and chloride prior to and around the time of felling (200 to 300 and 230 to 400 Eq/l, respectively), with a subsequent decline in concentration to pre-felling and to lower values of around 160 and 170 Eq/l, respectively, thereafter. This change is probably associated with abnormally high inputs of sea-salts from the atmosphere during the first quarter of the year of felling, and dilution thereafter, rather than a direct consequence of the felling activity itself: this change in sea salt loading has had an impact on stream acidity. Dissolved organic carbon and iron also change with concentrations increasing over time (60 to 200 and 1.0 to 1.5 M/l, respectively) and this mirrors a general pattern observed across the Plynlimon catchments irrespective of whether or not there has been felling activity.The implications of the findings are discussed in relations to environmental management and hydrochemical processes.     

A high performance liquid chromatography method for determination of gas-phase hydrogen peroxide in ambient air using Fenton's chemistry

A new method for determination of hydrogen peroxide in atmospheric samples is described. Cryogenically collected H2O2 is reacted with sodium salicylate in the presence of Fe(2+) to produce dihydroxybenzoate, which is separated from the reaction mixture by high performance liquid chromatography and detected by UV absorption. Measurements of atmospheric H2O2 were conducted in Las Vegas, NV from June 1999 to December 1999 to evaluate and characterize the method. Measured mixing ratios of H2O2 (there were also non-detects) ranged from 0.012 to 2.74 ppbv, with expected correlations to primary gaseous pollutants and strong seasonal variation consistent with a photochemically derived species. It was concluded that the method is easy to use and has sufficient sensitivity and selectivity to be useful in atmospheric monitoring.     

Communication and mutual resource exchange in north Florida hermit crabs

Summary The patterns of shell exchange in three species of hermit crabs which overlap in distribution and shell use were observed in the laboratory. Crabs showed no tendency to initiate more exchanges with conspecifics as compared with nonconspecific individuals and there were no specific size dominance effects. Lack of common communicatory patterns betweenClibararius vittatus andPagurus pollicaris was correlated with minimal actual exchange, whilePagurus impressus exchanged with both species and executed patterns in common with both. The pattern of shell exchanges and preferences indicated that, in some cases, both individuals may gain in interspecific exchanges.     

Evaluation of soil-washing process for “unwashable” clays and silts from the palmerton zinc site

The Palmerton Zinc Site is a Superfund site in Palmerton, Pennsylvania. Its former mineral processing operations have contaminated nearby wells and soils with zinc and cadmium. Preliminary analysis of soil and dust sampling conducted in May 1991 has revealed that the dust poses a potential threat to human health. Based on the results of a previous study, which showed a high percentage of silt and clay in soils from Palmerton residential properties, it was concluded that soil washing is not likely to be a viable method to treat the soil and dust contamination in Palmerton. However, since the completion of this study, a soil-washing process for “unwashable” clays and silts has been developed. A residential soil sample from Palmerton, which had low concentrations of arsenic, cadmium, and lead, and a somewhat high concentration of zinc, was washed in a bench-scale version of this process. The results showed that the new soil-washing process for “unwashable” clays and silts may be a viable method to treat the soil and dust contamination in Palmerton, depending on the soil quality criteria concentrations selected for site cleanup.     

Rapid prenatal diagnosis of 14 cases of triploidy using fish with multiple probes

Fluorescence in situ hybridization (FISH) of chromosome-specific probes to interphase nuclei can rapidly identify aneuploidies in uncultured amniotic fluid cells. Using DNA probe sets specific for chromosomes 13, 18, 21, X, and Y, we have identified 14 fetuses where the hybridization pattern was consistent with a triploid chromosome constitution. In each case, the identification of fetal abnormalities by ultrasound examination initiated a request for rapid determination of ploidy status via prenatal FISH analysis of uncultured amniocytes. FISH produced a three-signal pattern for the three autosomes in combination with signals indicating an XXX or XXY sex chromosome complement. This hybridization pattern was interpreted to be consistent with triploidy. Results were reported to the physician within 2 days of amniocentesis and subsequently confirmed by cytogenetics. These cases demonstrate the utility of FISH for rapid prenatal identification of triploidy, particularly when fetal abnormalities are seen with ultrasonographic examination.     

Mating success of male hermit crabs in shell generalist and shell specialist species

Summary The reproductive behavior of two species of diogenid hermit crabs was studied in Hawaii. In the shell generalist, Clibanarius zebra, male reproductive success varied little with size, although the largest males were less successful in obtaining copulations than were medium-large males. Male and female size were positively correlated, in successful pairs, thus larger males had the potential to fertilize more eggs when they were successful in obtaining a copulation. Female fecundity in C. zebra was not affected by species of gastropod shell inhabited once female size was taken into account. Male copulatory success was very strongly influenced by the species of gastropod shell inhabited. Males in Trochus or Nerita shells had greatly reduced reproductive success compared to males in Turbo or Nassarius shells. This result was due both to (1) males in Trochus especially dropping and otherwise poorly handling females during precopulatory behavior and (2) females not responding to precopulatory behavior patterns executed by males in Trochus and Nerita. Transferring males from good to bad shapes of shells and vice versa showed that male success was a function of shell type inhabited and not some correlated feature of the crabs. In the shell specialist, Calcinus seurati, which is found primarily in Nerita shells as an adult, males in Nerita shells were quite successful in obtaining copulations.