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 μm/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

Vasculo-neuronal coupling and neurovascular coupling at the neurovascular unit: impact of hypertension

Components of the neurovascular unit (NVU) establish dynamic crosstalk that regulates cerebral blood flow and maintain brain homeostasis. Here, we describe accumulating evidence for cellular elements of the NVU contributing to critical physiological processes such as cerebral autoregulation, neurovascular coupling, and vasculo-neuronal coupling. We discuss how alterations in the cellular mechanisms governing NVU homeostasis can lead to pathological changes in which vascular endothelial and smooth muscle cell, pericyte and astrocyte function may play a key role. Because hypertension is a modifiable risk factor for stroke and accelerated cognitive decline in aging, we focus on hypertension-associated changes on cerebral arteriole function and structure, and the molecular mechanisms through which these may contribute to cognitive decline. We gather recent emerging evidence concerning cognitive loss in hypertension and the link with vascular dementia and Alzheimer’s disease. Collectively, we summarize how vascular dysfunction, chronic hypoperfusion, oxidative stress, and inflammatory processes can uncouple communication at the NVU impairing cerebral perfusion and contributing to neurodegeneration.Fil: Presa, Jessica Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Augusta University Medical Center. Medical College of Georgia; Estados UnidosFil: Saravia, Flavia Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Bagi, Zsolt. Augusta University Medical Center. Medical College of Georgia; Estados UnidosFil: Filosa, Jessica A.. Augusta University Medical Center. Medical College of Georgia; Estados Unido

Assessing the acoustic behaviour of Anopheles gambiae (s.l.) dsxF mutants: implications for vector control

BACKGROUND: Release of gene-drive mutants to suppress Anopheles mosquito reproduction is a promising method of malaria control. However, many scientific, regulatory and ethical questions remain before transgenic mosquitoes can be utilised in the field. At a behavioural level, gene-drive carrying mutants should be at least as sexually attractive as the wildtype populations they compete against, with a key element of Anopheles copulation being acoustic courtship. We analysed sound emissions and acoustic preference in a doublesex mutant previously used to collapse Anopheles gambiae (s.l.) cages. METHODS: Anopheles rely on flight tones produced by the beating of their wings for acoustic mating communication. We assessed the impact of disrupting a female-specific isoform of the doublesex gene (dsxF) on the wing beat frequency (WBF; measured as flight tone) of males (XY) and females (XX) in homozygous dsxF- mutants (dsxF-/-), heterozygous dsxF- carriers (dsxF+/-) and G3 dsxF+ controls (dsxF+/+). To exclude non-genetic influences, we controlled for temperature and wing length. We used a phonotaxis assay to test the acoustic preferences of mutant and control mosquitoes. RESULTS: A previous study showed an altered phenotype only for dsxF-/- females, who appear intersex, suggesting that the female-specific dsxF allele is haplosufficient. We identified significant, dose-dependent increases in the WBF of both dsxF-/- and dsxF+/- females compared to dsxF+/+ females. All female WBFs remained significantly lower than male equivalents, though. Males showed stronger phonotactic responses to the WBFs of control dsxF+/+ females than to those of dsxF+/- and dsxF-/- females. We found no evidence of phonotaxis in any female genotype. No male genotypes displayed any deviations from controls. CONCLUSIONS: A prerequisite for anopheline copulation is the phonotactic attraction of males towards female flight tones within mating swarms. Reductions in mutant acoustic attractiveness diminish their mating efficiency and thus the efficacy of population control efforts. Caged population assessments may not successfully reproduce natural mating scenarios. We propose to amend existing testing protocols to better reflect competition between mutants and target populations. Our findings confirm that dsxF disruption has no effect on males; for some phenotypic traits, such as female WBFs, the effects of dsxF appear dose-dependent rather than haplosufficient

Unexpected Diagnosis of Complete Androgen Insensitivity Syndrome (CAIS) During Inguinal Hernia Repair in 11-year-old-girl

Complete Androgen Insensitivity Syndrome (CAIS) is an X-link recessive genetic mutation of androgen receptor (AR) gene leading to complete inability of cell to respond to the androgens. CAIS occurs in 1 out of 20,400 XY live-birth babies, and affects about 1–2% of prepubertal girls that present with an inguinal hernia. Although individuals with CAIS have XY, those with grades 6 and 7 on the Quigley scale are born phenotypically female, without any signs of genital masculinization. Thus, individuals affected by CAIS develop a normal external female phenotype with normal female external genitalia, well-developed breast, absent uterus, and bilateral undescended testicles. The question of CAIS diagnosis does not come forward until the absent menses at the puberty is noted or accidentally during an inguinal hernia repair in a premenarchal girl. The present study reports a case of inguinal hernia repair on 11-year-old girl, which led to unexpected intraoperative notion of CAIS. The diagnostic work-up, genetic counseling, sex assignment, and the need for preoperative CAIS screening in girls with bilateral inguinal hernia are described and discussed. Keywords: DSD, CAIS, bilateral inguinal hernia, gonadectom

Influence of Tinospora cordifolia on wound healing in wistar rats

Background: T.cordifolia is widely used in veterinary folk medicine ayurvedic system of medicine. It is known to possess various properties. In a study T.cordifolia promoted wound healing in diabetic patients. However, one study showed that octacosanol content in T.cordifolia possessed anti-angiogenic activity which can hinder wound healing. Therefore, effect of T.cordifolia on wound healing appears to be controversial and there is scarcity of information regarding its effect on wound healing in animal models.Methods: Excision wound, resutured incision wound and dead space wounds were inflicted under light thiopentone anesthesia in male wistar rats (n=6 in each group). Methanol extract of T.cordifolia stem in the dose of 250 mg/kg was administered orally once a day for 10 days in resutured incision (assessed by wound breaking strength), dead space (granuloma dry weight and histopathology of granulation tissue) excision wounds was monitored by planimetry. Data was expressed as mean±SEM and analyzed by student’s t-test. p <0.05 was considered as significant.Results: The results of the present study revealed that T.cordifolia significantly promotes wound healing in all the three models viz. enhanced wound contraction and decreased days for complete epithelization in excision wound; increased breaking strength in resutured incision wound; increased granuloma dry weight and cellular infiltration in granulation tissue.Conclusions: T.cordifolia significantly (p<0.05) promoted wound healing in all the three models of wound in male wistar rats

Stress and Strain in Flat Piling of Disks

We have created a flat piling of disks in a numerical experiment using the Distinct Element Method (DEM) by depositing them under gravity. In the resulting pile, we then measured increments in stress and strain that were associated with a small decrease in gravity. We first describe the stress in terms of the strain using isotropic elasticity theory. Then, from a micro-mechanical view point, we calculate the relation between the stress and strain using the mean strain assumption. We compare the predicted values of Young's modulus and Poisson's ratio with those that were measured in the numerical experiment.Comment: 9 pages, 1 table, 8 figures, and 2 pages for captions of figure

Force correlations and arches formation in granular assemblies

In the context of a simple microscopic schematic scalar model we study the effects of spatial correlations in force transmission in granular assemblies. We show that the parameters of the normalized weights distribution function, $P(v)\sim v^{\alpha}\exp(-v/\phi)$, strongly depend on the spatial extensions, $\xi_V$, of such correlations. We show, then, the connections between measurable macroscopic quantities and microscopic mechanisms enhancing correlations. In particular we evaluate how the exponential cut-off, $\phi(\xi_V)$, and the small forces power law exponent, $\alpha(\xi_V)$, depend on the correlation length, $\xi_V$. If correlations go to infinity, weights are power law distributed.Comment: 6 page

Hitting the right note at the right time: Circadian control of audibility in Anopheles mosquito mating swarms is mediated by flight tones

Mating swarms of malaria mosquitoes form every day at sunset throughout the tropical world. They typically last less than 30 minutes. Activity must thus be highly synchronized between the sexes. Moreover, males must identify the few sporadically entering females by detecting the females’ faint flight tones. We show that the Anopheles circadian clock not only ensures a tight synchrony of male and female activity but also helps sharpen the males’ acoustic detection system: By raising their flight tones to 1.5 times the female flight tone, males enhance the audibility of females, specifically at swarm time. Previously reported “harmonic convergence” events are only a random by-product of the mosquitoes’ flight tone variance and not a signature of acoustic interaction between males and females. The flight tones of individual mosquitoes occupy narrow, partly non-overlapping frequency ranges, suggesting that the audibility of individual females varies across males

Influence of hyperhomocysteinemia on the cellular redox state - Impact on homocysteine-induced endothelial dysfunction

Hyperhomocysteinemia is an independent risk factor for the development of atherosclerosis. An increasing body of evidence has implicated oxidative stress as being contributory to homocysteines deleterious effects on the vasculature. Elevated levels of homocysteine may lead to increased generation of superoxide by a biochemical mechanism involving nitric oxide synthase, and, to a lesser extent, by an increase in the chemical oxidation of homocysteine and other aminothiols in the circulation. The resultant increase in superoxide levels is further amplified by homocysteinedependent alterations in the function of cellular antioxidant enzymes such as cellular glutathione peroxidase or extracellular superoxide dismutase. One direct clinical consequence of elevated vascular superoxide levels is the inactivation of the vasorelaxant messenger nitric oxide, leading to endothelial dysfunction. Scavenging of superoxide anion by either superoxide dismutase or 4,5-dihydroxybenzene 1,3-disulfonate (Tiron) reverses endothelial dysfunction in hyperhomocysteinemic animal models and in isolated aortic rings incubated with homocysteine. Similarly, homocysteineinduced endothelial dysfunction is also reversed by increasing the concentration of the endogenous antioxidant glutathione or overexpressing cellular glutathione peroxidase in animal models of mild hyperhomocysteinemia. Taken together, these findings strongly suggest that the adverse vascular effects of homocysteine are at least partly mediated by oxidative inactivation of nitric oxide

A Model for Force Fluctuations in Bead Packs

We study theoretically the complex network of forces that is responsible for the static structure and properties of granular materials. We present detailed calculations for a model in which the fluctuations in the force distribution arise because of variations in the contact angles and the constraints imposed by the force balance on each bead of the pile. We compare our results for force distribution function for this model, including exact results for certain contact angle probability distributions, with numerical simulations of force distributions in random sphere packings. This model reproduces many aspects of the force distribution observed both in experiment and in numerical simulations of sphere packings