Southern Illinois University Carbondale

About: Southern Illinois University Carbondale is a education organization based out in Carbondale, Illinois, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 13570 authors who have published 24819 publications receiving 667385 citations. The organization is also known as: SIU Carbondale & SIUC.

Adaptive Mo2N/MoS2/Ag Tribological Nanocomposite Coatings for Aerospace Applications

Abstract: Reactively sputtered Mo2N/MoS2/Ag nanocomposite coatings were deposited from three individual Mo, MoS2, and Ag targets in a nitrogen environment onto Si (111), 440C grade stainless steel, and inconel 600 substrates. The power to the Mo target was kept constant, while power to the MoS2 and Ag targets was varied to obtain different coating compositions. The coatings consisted of Mo2N, with silver and/or sulfur additions of up to approximately 24 at%. Coating chemistry and crystal structure were evaluated using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), which showed the presence of tetragonal Mo2N and cubic Ag phases. The MoS2 phase was detected from XPS analysis and was likely present as an amorphous inclusion based on the absence of characteristic XRD peaks. The tribological properties of the coatings were investigated in dry sliding at room temperature against Si3N4, 440C stainless steel, and Al2O3. Tribological testing was also conducted at 350 and 600 °C against Si3N4. The coatings and respective wear tracks were examined using scanning electron microscopy (SEM), optical microscopy, profilometry, energy dispersive X-ray spectroscopy (EDX), and micro-Raman spectroscopy. During room temperature tests, the coefficients of friction (CoF) were relatively high (0.5–1.0) for all coating compositions, and particularly high against Si3N4 counterfaces. During high-temperature tests, the CoF of single-phase Mo2N coatings remained high, but much lower CoFs were observed for composite coatings with both Ag and S additions. CoF values were maintained as low as 0.1 over 10,000 cycles for samples with Ag content in excess of 16 at% and with sulfur content in the 5–14 at% range. The chemistry and phase analysis of coating contact surfaces showed temperature-adaptive behavior with the formation of metallic silver at 350 °C and silver molybdate compounds at 600 °C tests. These adaptive Mo2N/MoS2/Ag coatings exhibited wear rates that were two orders of magnitude lower compared to Mo2N and Mo2N/Ag coatings, hence providing a high potential for lubrication and wear prevention of high-temperature sliding contacts.

Temperature as a toxicity identification evaluation tool for pyrethroid insecticides: toxicokinetic confirmation

Abstract: Toxicity identification evaluation (TIE) methods can be used to identify toxic compounds in environmental samples using a variety of laboratory techniques. Whereas TIEs exist for nonpolar organics, relatively few methods are established for individual contaminant classes. Toxicity identification evaluations have shown pesticides to be the cause of toxicity in agricultural waters and effluents, and more recent studies have shown that the insecticide class of concern is pyrethroids. The primary objectives of the present study were to confirm a temperature TIE model and mechanistically explain these trends. This was achieved by comparing the relative toxicity and influence of temperature (13 vs 23°C) on Chironomus dilutus exposed to four insecticides, including two pyrethroids, an organophosphate, and an organochlorine, and then explaining these changes using toxicokinetics. A 10°C temperature decrease increased the toxicity of pyrethroids and DDT but decreased the toxicity of chlorpyrifos. The decrease in chlorpyrifos toxicity was driven primarily by the reduction of the formation of more toxic products via decreased biotransformation. The increase in DDT toxicity, in contrast, can be attributed to increased nerve sensitivity at 13 versus 23°C. The pyrethroid toxicity change, however, resulted from a combination of increased accumulation of parent compound and increased nerve sensitivity, exacerbating the toxicity of pyrethroids at 13°C. These trends also held true in sediment exposures with chlorpyrifos and permethrin, indicating that water-only exposures were adequate substitutes for examining this mechanism.

Predicted disease susceptibility in a panamanian amphibian assemblage based on skin peptide defenses

Abstract: Chytridiomycosis is an emerging infectious disease of amphibians caused by a chytrid fungus, Batrachochytrium dendrobatidis. This panzootic does not equally affect all amphibian species within an assemblage; some populations decline, others persist. Little is known about the factors that affect disease resistance. Differences in behavior, life history, biogeography, or immune function may impact survival. We found that an innate immune defense, antimicrobial skin peptides, varied significantly among species within a rainforest stream amphibian assemblage that has not been exposed to B. dendrobatidis. If exposed, all amphibian species at this central Panamanian site are at risk of population declines. In vitro pathogen growth inhibition by peptides from Panamanian species compared with species with known resistance (Rana pipiens and Xenopus laevis) or susceptibility (Bufo boreas) suggests that of the nine species examined, two species (Centrolene prosoblepon and Phyllomedusa lemur) may demonstrate strong resistance, and the other species will have a higher risk of disease-associated population declines. We found little variation among geographically distinct B. dendrobatidis isolates in sensitivity to an amphibian skin peptide mixture. This supports the hypothesis that B. dendrobatidis is a generalist pathogen and that species possessing an innate immunologic defense at the time of disease emergence are more likely to survive.

Abiotic nitrous oxide emission from the hypersaline Don Juan Pond in Antarctica

Abstract: Nitrous oxide is a potent atmospheric greenhouse gas that is thought to be produced in soils through biological processes. Field measurements reveal nitrous oxide fluxes near Don Juan Pond, Antarctica — of comparable magnitude to those found in tropical soils — which may result from abiotic water–rock reactions.

Methods of treating traumatic brain injury by vagus nerve stimulation

Abstract: Methods of modulating brain neural plasticity, improving memory and learning, improving recovery from traumatic brain injury, preventing epilepsy, treating memory disorders and chronic memory impairment, and treating persistent impairment of consciousness in humans and animals by vagus nerve stimulation are provided. These methods comprise selecting an appropriate human or animal subject and applying to the subject's vagus nerve an electrical stimulation signal having parameter values effective in modulating the electrical activity of the vagus nerve in a manner so as to modulate the activity of preselected portions of the brain.