96 research outputs found
Investigation of Metal and Organic Contaminant Distributions and Sedimentation Rates in Backwater Lakes along the Illinois River
Systematic sub-sampling of sediment cores in sections of uniform thickness is necessary
in order to evaluate historic changes in sediment quality, to determine the vertical extent
of contamination, and to measure sedimentation rates. With these objectives in mind,
fourteen sediment cores were collected during March 2002 using the Illinois State Water
Survey vibracorer. Concentrations of metals and total organic carbon were measured
using standard techniques. Concentrations of chlorinated pesticides, phenolic compounds,
polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) were
measured by gas chromatography/mass spectrometry (GC-MS). The concentrations of
chlorinated pesticides, phenolic compounds and polychlorinated biphenyls (PCBs) were
below the method detection limit in all sediment samples analyzed. However, there was
a wide range in concentrations of polycyclic aromatic hydrocarbons (PAHs) which were
detected in all sediment samples. Also, a wide range of metal concentrations was noted
in the sediments evaluated. Lower concentrations of metals were found in the upper 0.5
m of sediment but concentrations were elevated at depths ranging from 1.0 m to 1.5 m.
Sedimentation rates were estimated using cesium-137 radiometric dating on 14
vibracores. Sedimentation rates range from < 0.1 to 1.9 cm/yr, with an average of 0.9
cm/yr. These rates are comparable to those reported in previous studies.Illinois Sustainable Technology Centerpublished or submitted for publicationis peer reviewe
Flash Pyrolysis of Anthropogenic and Natural Organic Matter in Polluted Sediments
INTRODUCTION - Combustion products along with spilled petroleum and industrial chemicals contribute to environmental degradation by contaminating soils and sediments. Such anthropogenic organic matter (OM), if preserved in sediments, can serve an archival function, documenting the local, history of industrial pollution. Christensen and Zhang (1993) determined the sources of polycyclic aromatic hydrocarbons (P AH) to Lake Michigan from sedimentary records, finding that coal combustion was a major source for PAHs in these sediments. Bodzek and Luks-Betlej (1993) reported that atmospheric deposition is the main source of PAH in soils of the heavily industrialized Upper Silesia region of Poland. Smith and Levy (1990) investigated the geochronology of PAH contamination in sediments of the Saguenay Fjord (Quebec). They found that the concentrations and fluxes of P AHs in these sediments track developments in the region\u27s aluminum industry. OM in sediment samples from a 3 m core was investigated to determine the impact of industrialization on the natural environment of the study area, a polluted industrial zone near Chicago, Illinois (West Branch of the Grand Calumet River). In an attempt to examine the extent of chemical contamination in these sediments, the present study used analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC-MS) and petrography to characterize the anthropogenic and natural OM.
METHODS - A 3 m sediment core was collected using a portable vibracoring system (River Mile 9.0, West Branch of the Calumet River, Burham, Illinois, USA). Aliquots of eleven samples of dry sediment were mixed with epoxy resin and mounted into pellets for petrography. Total organic carbon (TOC) was determined for each sample. Py-GC-MS was used to chemically characterize sedimentary organic matter in these sediments. For each GC/MS run 5 mg of dry sediment contained in a quartz tube was placed in platinum coil and pyrolyzed in a flow of helium for 20 sec. at 610 °C, as measured by a thermocouple in the sample holder. Prior to pyrolysis, the samples were heated at 310 °C for 20 sec. to remove low molecular weight OM, which was analyzed separately and is not discussed here.
RESULTS - Petrographic analyses indicate the presence in the sediments of eight types of OM of which three have been identified as debris of natural vegetation. Other organic particles, including coal, metallurgical coke, petroleum coke, char, fly ash, and solid bitumen, are anthropogenic and related to industrial activity. Anthropogenic particles are dominant in sediments in the upper core, while plant fragments dominate OM at core bottom.
Pyrolyzates of the sediments in the top meter are dominated by chemical pollutants that are related to pyrolytic sources. These include PAHs, thioarenes, azaarenes and aliphatic hydrocarbons (Fig. 1). The aromatic hydrocarbons in pyrolyzates of the top sediments are predominantly three, four and five-ring parent PAHs. Bouloubassi and Saliot (1995) observed the prominence of such compounds in OM from pyrolytic sources in surface sediments collected in the Rhone delta. Concentrations of PAHs in pyrolyzates decrease with increasing depth to background levels by approximately 120 cm, the core depth at which we infer to record the local onset of industrialization.
Various classes of sulfur compounds are present in pyrolyzates of the sediments. Among the organic sulfur compounds detected in our samples, the thioarenes (benzothiophenes, dibenzothiophenes, benzonaphthothiophenes, and their alkyl-substituted homologues) were the most abundant. The sum of their concentrations in the pyrolyzates of the sediments varied from 125 to 473 ÎŒm/g in the top 76 cm. The concentrations of thioarenes showed trends with depth similar to those shown by PAHs. Steinhauer and Boehm (1992) reported that uncombusted fossil fuels are highly enriched in two- to three-ring PAHs and thioarenes.
Most of the nitrogen in the pyrolyzates is found to be present in aromatic forms (simple and alkylated multi-ring azaarenes), with small amounts of alkyl amine and amides. Azaarenes often have stronger mutagenic and carcinogenic activity than the PAHs (Tyreplen et al., 1995) and thus are cause for concern. As with P AHs, concentrations of azaarenes in pyrolyzates are higher in shallower sediments. Tyreplen and others (1995) reported the presence of azaarenes (e.g. isoquinoline, acridine, and their isomers) and their alkyl derivatives in sewage sludge from treatments plants in the Upper Silesia region, Poland. Low abundances of single ring N-compounds (pyrrole and pyridine) were observed in pyrolysis products of sediments above 106 cm, whereas higher concentrations were detected in pyrolyzates of the older sediments below that depth. These compounds may arise in part from pyrolysis of proteinaceous material.
Moderate to low concentrations of aliphatic hydrocarbons were detected in pyrolyzates of the sediments. Concentrations of short chain n-alkane and n-alkenes (C6-C19) in pyrolyzates are highest in pyrolyzates of the top sediments, while long chain (C20-C29) n-alkanes, n-alkenes, and prist-1-ene are dominant in sediments at the bottom of the core. This may indicate that aliphatic hydrocarbons at the top of the core are mostly pyrolysis products of anthropogenic OM such as petroleum asphaltenes, whereas for deeper older samples, long chain aliphatics have resulted from pyrolysis of naturally occurring terrestrial higher plant OM.
Pyrolyzates of bottom sediments are dominated by lignin-derived compounds including phenols, methoxyphenols and dimethoxyphenols (Fig. 2). The lignin pyrolysis products guaiacol, syringol, and their derivatives are restricted to the bottom 2 m of the core. The presence of guaiacols and syringols in pyrolyzates of samples below 120 cm correlates with the occurrence of plant fragments, as observed under the microscope. The lack of lignin marker compounds in the upper sediments suggests a reduction in plant populations in the vicinity during the industrial period Phenol and its alkyl-substituted forms are less specific marker compounds, occurring in pyrolyzates of all sediment samples . Their presence in pyrolysis products of the older sediments (below 106 cm) is probably due to naturally-occurring OM (terrestrial higher plants). However, phenols in pyrolyzates of the younger sediments probably derive from the abundant coal particles (vitrinite) observed petrographically.
CONCLUSION - The abundance of anthropogenic OM in pyrolyzates of sediments that correspond to the time of peak industrialization is over 10 times higher than the background levels detected in bottom sediments. It is evident that industrial activity has resulted in irreversible damage to the marshes and the wetlands of this area with the result that plant life has never recovered. Py-GC/MS analysis of organic sediments proved to be useful in determining the extent of pollution in these sediments and highlights some of the compositional features that can be used to distinguish between natural and anthropogenic OM.
REFERENCES
Bodzek, D. and Luks-Betlej, K. (1993) A preliminary study on the effect of air pollution on the contamination of the soil by polycyclic aromatic hydrocarbons: in Organic Geochemistry Poster Session from the 16th International Meeting on Organic Geochemistry, Stavanger 1993.
Bouloubassi, I., and Saliot, A. (1995) Investigation of anthropogenic and natural organic inputs in estuarine sediments using hydrocarbon markers (NAH, LAB, PAH). Oceanologica Acta, 16, 145-161.
Christensen, E. R., and Zhang, X. (1993) Sources of polycyclic aromatic hydrocarbons to Lake Michigan determined from sedimentary records. Environ. Sci. Technol., 27(1), 139-146.
Smith, J. N., and Levy, E. M. (1990) Geochronology for polycyclic aromatic hydrocarbon contamination in sediments of Saguenay Fjord. Environ. Sci. Technol., 24, 847-879.
Steinhauer, M. S. and Boehm, P. D. (1992) The composition and the distribution of saturated and aromatic hydrocarbons in near-shore sediments, river sediments, and coastal peat of the Alaskan Beaufort Sea: Implication for detecting anthropogenic hydrocarbon inputs. Marine Environmental Research, 33, 223-253
Tyreplen, K., Bodzek, 0., and Janoszka, B., (1995) Application of TLC and GC/MS to the identification of azaarenes in sewage sludge. J. Planar Chromatogr., 8, 75-77
Vole Problems, Management Options, and Research Needs in the United States
Voles (Microtus spp.) are ubiquitous to the northern hemisphere. Numerous species occur in North America and several species cause significant damage of various types: food crops, livestock forage production (e.g., alfalfa), nursery trees, reforestation, orchards, rangeland forage, and damage to lawns, golf courses and ground cover. Much research has been conducted with voles and a number of management options have been developed, including habitat manipulation, rodenticides, traps, repellents, barriers, supplemental feeding, and increased natural predation. However, significant damage still occurs because voles are not easily managed. Voles are small and secretive, prolific, active year-round, able to exploit refugia, and cyclic with periodic irruptions. Currently there are no permanent solutions to managing voles, so long-term monitoring and management of populations is required. We review what is known about voles, the types and extent of damage they cause, advantages and disadvantages of management methods, and some research needs. Research needs include the development of effective repellents, effective rodenticide baiting strategies that minimize nontarget hazards, and cost-effective methods to protect the root systems of woody plants
GS-5759, a Bifunctional b 2 -Adrenoceptor Agonist and Phosphodiesterase 4 Inhibitor for Chronic Obstructive Pulmonary Disease with a Unique Mode of Action: Effects on Gene Expression in Human Airway Epithelial Cells s
) and propranolol, were agonist-dependent, being significantly lower for GS-5759 than b2A. Collectively, these data can be explained by "forced proximity," bivalent binding where the pharmacophore in GS-5759 responsible for PDE4 inhibition also interacts with a nonallosteric domain within the b 2 -adrenoceptor that enhances the affinity of b2A for the orthosteric site. Microarray analyses revealed that, after 2-hour exposure, GS-5759 increased the expression of .3500 genes in BEAS-2B cells that were highly rank-order correlated with gene expression changes produced by indacaterol and GSK 256066 in combination (Ind/GSK). Moreover, the line of regression began close to the origin with a slope of 0.88, indicating that the magnitude of most gene expression changes produced by Ind/GSK was quantitatively replicated by GS-5759. Thus, GS-5759 is a novel compound exhibiting dual b 2 -adrenoceptor agonism and PDE4 inhibition with potential to interact on target tissues in a synergistic manner. Such polypharmacological behavior may be particularly effective in chronic obstructive pulmonary disease and other complex disorders where multiple processes interact to promote disease pathogenesis and progression
Thermal conductivity of refractory glass fibres
In the present study, the current international
standards and corresponding apparatus for measuring the
thermal conductivity of refractory glass fibre products have
been reviewed. Refractory glass fibres are normally produced
in the form of low-density needled mats. A major
issue with thermal conductivity measurements of these
materials is lack of reproducibility in the test results due to
transformation of the test material during the test. Also
needled mats are inherently inhomogeneous, and this poses
additional problems. To be able to compare the various
methods of thermal conductivity measurement, a refractory
reference material was designed which is capable of
withstanding maximum test temperatures (1673 K) with
minimum transformation. The thermal conductivity of this
reference material was then measured using various
methods according to the different standards surveyed. In
order to compare different materials, samples have been
acquired from major refractory glass fibre manufacturers
and the results have been compared against the newly
introduced reference material. Materials manufactured by
melt spinning, melt blowing and solâgel have been studied,
and results compared with literature values
Metabolic Deficiences Revealed in the Biotechnologically Important Model Bacterium Escherichia coli BL21(DE3)
The Escherichia coli B strain BL21(DE3) has had a profound impact on biotechnology through its use in the production of recombinant proteins. Little is understood, however, regarding the physiology of this important E. coli strain. We show here that BL21(DE3) totally lacks activity of the four [NiFe]-hydrogenases, the three molybdenum- and selenium-containing formate dehydrogenases and molybdenum-dependent nitrate reductase. Nevertheless, all of the structural genes necessary for the synthesis of the respective anaerobic metalloenzymes are present in the genome. However, the genes encoding the high-affinity molybdate transport system and the molybdenum-responsive transcriptional regulator ModE are absent from the genome. Moreover, BL21(DE3) has a nonsense mutation in the gene encoding the global oxygen-responsive transcriptional regulator FNR. The activities of the two hydrogen-oxidizing hydrogenases, therefore, could be restored to BL21(DE3) by supplementing the growth medium with high concentrations of Ni2+ (Ni2+-transport is FNR-dependent) or by introducing a wild-type copy of the fnr gene. Only combined addition of plasmid-encoded fnr and high concentrations of MoO42â ions could restore hydrogen production to BL21(DE3); however, to only 25â30% of a K-12 wildtype. We could show that limited hydrogen production from the enzyme complex responsible for formate-dependent hydrogen evolution was due solely to reduced activity of the formate dehydrogenase (FDH-H), not the hydrogenase component. The activity of the FNR-dependent formate dehydrogenase, FDH-N, could not be restored, even when the fnr gene and MoO42â were supplied; however, nitrate reductase activity could be recovered by combined addition of MoO42â and the fnr gene. This suggested that a further component specific for biosynthesis or activity of formate dehydrogenases H and N was missing. Re-introduction of the gene encoding ModE could only partially restore the activities of both enzymes. Taken together these results demonstrate that BL21(DE3) has major defects in anaerobic metabolism, metal ion transport and metalloprotein biosynthesis
Purinergic signalling links mechanical breath profile and alveolar mechanics with the pro-inflammatory innate immune response causing ventilation-induced lung injury
Severe pulmonary infection or vigorous cyclic deformation of the alveolar epithelial type I (AT I) cells by mechanical ventilation leads to massive extracellular ATP release. High levels of extracellular ATP saturate the ATP hydrolysis enzymes CD39 and CD73 resulting in persistent high ATP levels despite the conversion to adenosine. Above a certain level, extracellular ATP molecules act as danger-associated molecular patterns (DAMPs) and activate the pro-inflammatory response of the innate immunity through purinergic receptors on the surface of the immune cells. This results in lung tissue inflammation, capillary leakage, interstitial and alveolar oedema and lung injury reducing the production of surfactant by the damaged AT II cells and deactivating the surfactant function by the concomitant extravasated serum proteins through capillary leakage followed by a substantial increase in alveolar surface tension and alveolar collapse. The resulting inhomogeneous ventilation of the lungs is an important mechanism in the development of ventilation-induced lung injury. The high levels of extracellular ATP and the upregulation of ecto-enzymes and soluble enzymes that hydrolyse ATP to adenosine (CD39 and CD73) increase the extracellular adenosine levels that inhibit the innate and adaptive immune responses rendering the host susceptible to infection by invading microorganisms. Moreover, high levels of extracellular adenosine increase the expression, the production and the activation of pro-fibrotic proteins (such as TGF-ÎČ, α-SMA, etc.) followed by the establishment of lung fibrosis
Why Did so Many People Make so Many Ex Post Bad Decisions? The Causes of the Foreclosure Crisis
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 nonâcritically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (nâ=â257), ARB (nâ=â248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; nâ=â10), or no RAS inhibitor (control; nâ=â264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ supportâfree days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ supportâfree days among critically ill patients was 10 (â1 to 16) in the ACE inhibitor group (nâ=â231), 8 (â1 to 17) in the ARB group (nâ=â217), and 12 (0 to 17) in the control group (nâ=â231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ supportâfree days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570
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