Category Archives: Science & Technology

Topics such as cyber security, severe weather, space, Earth, oceans, and scientific research.

Epidemiology of nontuberculous mycobacteria isolations among central North Carolina residents, 2006-2010

BACKGROUND: Nontuberculous mycobacteria (NTM) are environmental mycobacteria associated with a range of infections. Reports of NTM epidemiology have primarily focused on pulmonary infections and isolations, however extrapulmonary infections of the skin, soft tissues and sterile sites are less frequently described.METHODS: We comprehensively reviewed laboratory reports of NTM isolation from North Carolina residents of three counties during 2006-2010. We describe age, gender, and race of patients, and anatomic site of isolation for NTM species.RESULTS:Among 1033 patients, overall NTM isolation prevalence was 15.9/100,000 persons(13.7/100,000 excluding Mycobacterium gordonae). Prevalence was similar between genders and increased significantly with age. Extrapulmonary isolations among middle-aged black males and pulmonary isolations among elderly white females were most frequently detected. Most isolations from pulmonary sites and blood cultures were Mycobacterium avium complex; rapidly growing NTM (e.g. Mycobacterium chelonae, Mycobacterium fortuitum) were most often isolated from paranasal sinuses, wounds and skin.CONCLUSIONS: We provide the first characterization of NTM isolation prevalence in the Southeastern United States (U.S.). Variation in isolation prevalence among counties and races likely represent differences in detection, demographics and risk factors. Further characterization of NTM epidemiology is increasingly important as percentages of immunocompromised individuals and the elderly increase in the U.S.

Identification of Modulators of the Nuclear Receptor Peroxisome Proliferator-Activated Receptor α (PPARα) in a Mouse Liver Gene Expression Compendium

The nuclear receptor family member peroxisome proliferator-activated receptor α (PPARα) is activated by therapeutic hypolipidemic drugs and environmentally-relevant chemicals to regulate genes involved in lipid transport and catabolism. Chronic activation of PPARα in rodents increases in liver cancer incidence, whereas suppression of PPARα activity can lead to hepatocellular steatosis. Analytical approaches were developed to identify biosets (i.e., gene expression differences between two conditions) in a genomic database in which PPARα activity was altered. A gene expression signature of 131 PPARα-dependent genes was built using profiles from the livers of wild-type and PPARα-null mice after exposure to three structurally diverse PPARα activators (WY-14,643, fenofibrate and perfluorohexane sulfonate). A rank-based test (Running Fisher’s test (p-value ≤ 10-4)) was used to evaluate the similarity between the PPARα signature and a test set of 48 and 31 biosets positive or negative, respectively for PPARα activation; the test resulted in a balanced accuracy of 98%. The signature was used to identify factors that activate or suppress PPARα in an annotated mouse liver/primary hepatocyte gene expression database of ~1850 biosets. In addition to the expected activation of PPARα by fibrate drugs, di(2-ethylhexyl) phthalate, and perfluorinated compounds, PPARα was activated by benzofuran, galactosamine and TCDD and suppressed by hepatotoxins acetaminophen, lipopolysaccharide, silicon dioxide nanoparticles and trovafloxacin. Additional factors that activate (fasting, caloric restriction) or suppress (infections) PPARα were also identified. This study 1) developed methods useful for future screening of environmental chemicals, 2) identified novel chemicals that activate or suppress PPARα, and 3) identified factors including diet and infection that modulate PPARα activity and would be hypothesized to affect chemical-induced PPARα activity. (265 words)

Screening a mouse liver gene expression Compendium Identifies Effectors of the Aryl Hydrocarbon receptor (AhR)

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates the biological and toxic effects of 2,3, 7 ,8-tetrachlorodibenzo-p-dioxin {TCDD), dioxin-like compounds (DLC) as well as some drugs and endogenous tryptophan metabolites. Short-term activation of AhR can lead to hepatocellular steatosis; chronic activation can lead to liver cancer in mice and rats. Analytical approaches were developed to identify b[osets in a genomic database in which AhR activity was altered. A set of 63 genes was identified (the AhR gene expression signature) that was dependent on AhR for regulation after exposure to TCDD or benzo[a]pyrene and includes the known AhR targets Cypl al and Cypl bl . A fold-change rank-based test (Running Fisher’s test; p-value :S 10-4) was used to evaluate the similarity between the AhR signature and a test set of 3 7 and 41 biosets positive or negative, respectively for AhR activation; the test resulted in a balanced accuracy of 89%. The rank-based test was used to identify factors that activate or suppress AhR in an annotated mouse liver/primary hepatocyte gene expression database of -1850 comparisons. In addition to the expected activation of AhR by TCDD and DLC, AhR was activated by AP20189 and phenformin. AhR was suppressed by phenobarbital and 1 ,4-Bis[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP) in a constitutive activated receptor (CAR)-dependent manner and pregnenolone-16a-carbonitrile in a pregnane X receptor (PXR)-dependent manner. Inactivation of individual genes in nullizygous models led to AhR activation (Pxr, Ghrhr, Tajl 0) or suppression (Ahr, Ilst6st, Hnfl a). This study describes a novel screening strategy for identifying factors that perturb AhR in a gene expression compendium. (249 words)

Regional patterns of total nitrogen concentrations in the National Rivers and Streams Assessment

Patterns of nitrogen concentrations in streams sampled by the National Rivers and Streams Assessment (NRSA) were examined semi-quantitatively to identify regional differences in stream nitrogen levels. The data were categorized and analyzed by watershed size classes to reveal patterns of the concentrations that are consistent with the spatial homogeneity in natural and anthropogenic characteristics associated with regional differences in nitrogen levels. Ecoregions and mapped information on human activities including agricultural practices were used to determine the resultant regions. Marked differences in nitrogen levels were found among the nine aggregations of ecoregions used to report the results of the NRSA. We identified distinct regional patterns of stream nitrogen concentrations within the reporting regions that are associated with the characteristics of specific Level III ecoregions, groups of Level III ecoregions, groups of Level IV ecoregions, certain geographic characteristics within ecoregions, and/or particular watershed size classes. We described each of these regions and illustrated their areal extent and median and range in nitrogen concentrations. Understanding the spatial variability of nutrient concentrations in flowing waters and the apparent contributions that human and non-human factors have on different sizes of streams and rivers is critical to the development of effective water quality assessment and management plans. This semi-quantitative analysis is also intended to identify areas within which more detailed quantitative work can be conducted to determine specific regional factors associated with variations in stream nitrogen concentrations.

Glyphosate and dicamba herbicide tank mixture effects on native plant and non-genetically engineered soybean seedlings

Weed species are becoming resistant to intensive and extensive use of specific herbicides associated with the production of herbicide resistant crops, e.g., the use of glyphosate for weed management with glyphosate resistant soybeans. To counter this resistance, crops engineered to contain genes for tolerance to both glyphosate and dicamba may be treated with both herbicides to manage weeds resistant to either herbicide. Thus, non-target plants may be subjected to aerial drift from two herbicides used in combination. Of particular concern are native plants which provide resources for wildlife, as well as adjacent crops which have not been genetically engineered for tolerance to herbicides. We evaluated the responses of eight species of native plants to simulated drift of glyphosate and/or dicamba: Andropogon gerardii, Asclepias syriaca, Eutrochium pupureum, Oenothera biennis, Polyganum lapathifolium, Solidago canadenses and Tridens flavus, and non-herbicide resistant soybean (Glycine max, cultivar Oregon 14). Herbicide concentrations representing aerial drift were used, 0.03 or 0.1 x field application rates of 1122 g ha-1 active ingredient (a.i) (831 g ha-1 acid glyphosate) for glyphosate and 562 g ha-1 a.i. for dicamba. Plants were grown in a greenhouse using a modification of the EPA’s vegetative vigor testing protocol. In general, the response to combinations of glyphosate and dicamba was similar to the response to either glyphosate or dicamba alone, depending on species and on which individual herbicide produced the greater effect. Solidago canadenses was the most sensitive species to both herbicides, while A. gerardii was the most tolerant, with only a slight response to glyphosate. The combinations resulted in responses most similar to that from dicamba alone for A. syriaca, G. max, P. lapathifolium, S. canadensis; and from glyphosate alone for T. flavus. The results of this study indicated the need for more data to assess risks to non-target plants from combinations of herbicides.

Accelerating Adverse Outcome Pathway Development Using Publicly Available Data Sources

The adverse outcome pathway (AOP) concept links molecular perturbations with organism and population-level outcomes to support high-throughput toxicity testing. International efforts are underway to define AOPs and store the information supporting these AOPs in a central knowledgebase, however, this process is currently labor-intensive and time-consuming. Publicly available data sources provide a wealth of information that could be used to define computationally-predicted AOPs (cpAOPs), which could serve as a basis for creating expert-derived AOPs in a much more efficient way. Computational tools for mining large datasets provide the means for extracting and organizing the information captured in these public data sources. Using cpAOPs as a starting point for expert-derived AOPs should accelerate AOP development. Coupling this with tools to coordinate and facilitate the expert development efforts will increase the number and quality of AOPs produced, which should play a key role in advancing the adoption of twenty-first century toxicity testing strategies.

Antarctic detector offers first look at how Earth stops high-energy neutrinos in their tracks

A Digital Optical Module

An interdisciplinary team of researchers using the IceCube Neutrino Observatory in Antarctica has measured how certain high-energy neutrinos are absorbed by the Earth, as opposed to passing through matter as most neutrinos do. The finding could help expand scientists’ understanding of the fundamental forces of the universe.

Funded and managed by the National Science Foundation (NSF), the IceCube Neutrino Observatory conducts research into these nearly massless

More at https://www.nsf.gov/news/news_summ.jsp?cntn_id=243782&WT.mc_id=USNSF_51&WT.mc_ev=click


This is an NSF News item.

Chemical-gene interaction networks and causal reasoning for biological effects prediction and prioritization of contaminants for environmental monitoring and surveillance (poster)

Product Description:Evaluation of the potential effects of complex mixtures of chemicals in the environment is challenged by the lack of extensive toxicity data for many chemicals. However, there are growing sources of online information that curate and compile literature reports of chemical interactions with various genes, proteins, and biological pathways. We show how this information can be leveraged to generate testable hypotheses regarding potential effects of chemicals detected in the environment and how this can help focus monitoring.
Evaluating the potential human health and ecological risks associated with exposures to complex chemical mixtures in the environment is one of the main challenges of chemical safety assessment and environmental protection. There is a need for the development of approaches to integrate chemical monitoring and biological effects data to evaluate risks associated with chemicals present in the environment. Here, we used prior knowledge about chemical-gene interactions to develop a knowledge assembly model (KAM) for detected chemicals at five locations near the North Branch and Chisago wastewater treatment plants (WWTP) in the St. Croix River Basin, MN and WI. Site-specific KAMs were developed to generate hypotheses about the potential biological impacts of the chemicals at each location. Additionally, empirical gene expression data were also mapped to the assembly models to evaluate the likelihood of a chemical contributing to the observed biological responses using richness and concordance statistics. The integration of the gene expression data with the site-specific KAMs allowed for the prioritization of potential chemical contributors at each location. Atrazine was identified as a potential contributor to the observed gene expression responses at a location upstream of the North Branch WTTP. Four chemicals were identified as contributors to the observed biological responses at the effluent and downstream of the North Branch WWTP, with carbamazepine being a significant contributor at both locations. Four chemicals were identified as the greatest contributors to the observed biological responses in fish exposed to the effluent at the Chisago WWTP. Five chemicals were identified as contributors to the observed biological responses in fish exposed downstream of the Chisago WWTP, with 17-estradiol and estrone being two of the significant chemicals. Knowledge assembly models have strong potential for associating chemical occurrence with potential biological effects and providing a foundation for hypothesis generation to guide research and/or monitoring efforts related to the effects of contaminants in the environment.

Neurotoxicological and thyroid evaluations of rats developmentally exposed to tris(1,3-dichloro-2-propyl)phosphate (TDICPP) and tris(2-chloro-2-ethyl)phosphate(TCEP)

ABSTRACT: Tris(1,3-dichloro-2-propyl)phosphate (TDICPP) and tris(2-chloro-2-ethyl)phosphate (TCEP) are organophosphorous flame retardants with widespread usage and human exposures through food, inhalation, and dust ingestion. They have been detected in human tissues including urine and breast milk. Reports of disrupted neural growth in vitro, abnormal development in larval zebrafish, and altered thyroid hormones in several species have raised concern for neurodevelopmental toxicity. This is especially the case for TDICPP, which is more potent and has more activity in these assays than does TCEP. We evaluated the potential for developmental neurotoxicity of TDICPP and TCEP in a mammalian model. Pregnant Long-Evans rats were administered TDICPP (15, 50, or 150 mg/kg/d) or TCEP (12, 40, 90 mg/kg/d) via oral gavage from gestational day 10 to weaning. Corn oil was the vehicle control in both studies. Body weight and righting reflex development were monitored in all pups. A subset of offspring at culling and weaning, and dams at weaning, were sacrificed for serum and organ collection for measurement of brain, liver, and thyroid weights, serum thyroid levels, and serum and brain acetylcholinesterase activity. Brain weights were also measured in a group of adult TDICPP-treated offspring. One male and one female from each litter were allocated for behavioral testing at several ages: standard locomotor activity (preweaning, postweaning, adults), activity including a lighting change mid-way (postweaning, adults), elevated zero maze (postweaning, adults), functional observational battery (FOB; postweaning, adults), and Morris water maze (place learning, working memory; adults). Neither chemical produced changes in maternal body weight or serum thyroid hormones, but relative liver weight was increased at the high doses of both TDICPP and TCEP. In offspring, there were no effects on viability, litter size, or birth weight. With TDICPP, absolute liver weights were lower at weaning and weight gain was lower in the high-dose offspring until about two months of age. Thyroid hormones and brain weights were not altered, and acetylcholinesterase was not inhibited, by either chemical, TDICPP-treated offspring showed slight differences in floating in the water maze, hindlimb grip strength, and altered activity habituation, whereas TCEP-treated rats showed differences in quadrant time (probe) and middle-zone preference in the water maze. Regarding these few changes, the effects were minimal, mostly not related to dose, and did not appear treatment-related or biologically significant. Overall, these data do not support the potential for thyrotoxicity or developmental neurotoxicity produced by TDICPP or TCEP. 

Locomotor activity and tissue levels following acute administration of lambda- and gamma-cyhalothrin in rats

Pyrethroids produce neurotoxicity that depends, in part, on the chemical structure. Common behavioral effects include locomotor activity changes and specific toxic syndromes (types I and II). In general these neurobehavioral effects correlate well with peak internal dose metrics. Products of cyhalothrin, a type II pyrethroid, include mixtures of isomers (e.g., λ-cyhalothrin) as well as enriched active isomers (e.g., γ-cyhalothrin). We measured acute changes in locomotor activity in adult male rats and directly correlated these changes to peak brain and plasma concentrations of λ- and γ-cyhalothrin using a within-subject design. One-hour locomotor activity studies were conducted 1.5 h after oral gavage dosing, and immediately thereafter plasma and brains were collected for analyzing tissue levels using LC/MS/MS methods. Both isomers produced dose-related decreases in activity counts, and the effective dose range for γ-cyhalothrin was lower than for λ-cyhalothrin. Doses calculated to decrease activity by 50% were 2-fold lower for the γ-isomer (1.29 mg/kg) compared to λ-cyhalothrin (2.65 mg/kg). Salivation, typical of type II pyrethroids, was also observed at lower doses of γ-cyhalothrin. Administered dose correlated well with brain and plasma concentrations, which furthermore showed good correlations with activity changes. Brain and plasma levels were tightly correlated across doses. While γ-cyhalothrin was 2-fold more potent based on administered dose, the differences based on internal concentrations was less, with γ-cyhalothrin being 1.3- to 1.6-fold more potent than λ-cyhalothrin. These potency differences are consistent with the purity of the λ-isomer (approximately 43%) compared to the enriched isomer γ-cyhalothrin (approximately 98%). Thus, administered dose as well as differences in cyhalothrin isomers are a good predictor of behavioral effects.

Assessment of the vitro dermal irritation of cerium silver and titanium nanoparticles in a human skin equivalent model

AbstractDermal exposure to metals may res·ult in irritant contact dermatitis. This study examined the potential of metal nanoparticles to elicit irritant contact dermatitis in a human skin equivalent model (HSEM) derived from epidermal keratinocytes. These cultured cells form a multi-layered,highly differentiated model of human, skin. Several Ag (10-100 nm), Ti02 (22-214 nm) and Ce02 (15-70 nm) nanoparticles were used. The Ag particles were either coated/shelled with silica or capped with citrate or polyvinylpyrrolidone. The Ag nanoparticles were dissolved in water. The Ti02 and Ce02 particles were suspended in cell culture media containing 10% fetal bovine serum. Stock suspensions of these particles were dispersed using a probe sonicator. The particles (1 mg/ml) were applied to the epidermal surface of the HSEM. Three to four wells of HSEM were tested per particle. The positive control was 5% sodium dodecyl sulfate (SDS) and the negative control was either saline or culture media. After 1 h exposure at 37 °C, the HSEM was washed with saline, and then incubated for 42 hat 37 °C, with a change of media at 24 h. Viability of the H~EM was assessed using the MTT assay. A test substance is considered an irritant if the HSEM viability is < 501Yo. The mean viability for the SDS treated HSEM was 7.8%. The viabilities of the nanoparticle treated HSEM were 91% or greater. Under the in vitroconditions used in this study, the Ag, Ti02 and Ce02 nanoparticles examined were not dermal irritants. The formed stratum corneum of the HSEM may limit penetration of metal nanoparticles to induce inflammation and cell death, or their inherent dermal irritancy potential is very low.

Differential Expression of pro-inflammatory and oxidative stress mediators induced by nitrogen dioxide and ozone in primary human bronchial epithelial cells

CONTEXT: N02 and 03 are ubiquitous air toxicants capable of inducing lung damage to the respiratory epithelium. Due to their oxidizing capabilities, these pollutants have been proposed to target specific biological pathways, but few publications have compared the pathways activated.OBJECTIVE: This work will test the premise that N02 and 03 induce toxicity by activating similar cellular pathways.METHODS: Primary human bronchial epithelial cells (HBECs, n = 3 donors) were exposed for 2 h at an air-liquid interface to 3 ppm N02, 0.75 ppm 03, or filtered air and harvested 1 h post­ exposure. To give an overview of pathways that may be influenced by each exposure, gene expression was measured using PCR arrays for toxicity and oxidative stress. Based on the results, genes were selected to quantify whether expression changes were changed in a dose­ and time-response manner using N02 (1, 2, 3, or 5 ppm), 03 (0.25, 0.50, 0.75, or 1.00ppm), orfiltered air and harvesting 0, 1,4 and 24 h post-exposure.RESULTS: Using the arrays, genes related to oxidative stress were highly induced with N02 while expression of pro-inflammatory and vascular function genes was found subsequent to 03. N02 elicited the greatest HMOX1 response, whereas 03 more greatly induced IL-6, IL-8 and PTGS2 expression. Additionally, 03 elicited a greater response 1 h post-exposure and N02 produced a maximal response after 4 h.CONCLUSION: We have demonstrated that these two oxidant gases stimulate differing mechanistic responses in vitro and these responses occur at dissimilar times.

Repeated measures of inflammation, blood pressure, and heart rate variability associated with personal traffic exposures in healthy adults

BACKGROUND: Previous human exposure studies of traffic-related air pollutants have demonstrated adverse health effects in human populations by comparing areas of high and low traffic, but few studies have utilized microenvironmental monitoring of pollutants at multiple traffic locations while looking at a vast array of health endpoints in the same population. We evaluated inflammatory markers, heart rate variablity (HRV), blood pressure,exhaled nitric oxide, and lung function in healthy participants after exposures to varying mixtures of traffic pollutants.METHODS:A repeated-measures, crossover study design was used in which 23 healthy, non­ smoking adults had clinical cardiopulmonary and systemic inflammatory measurements taken prior to, immediately after, and 24 hours after intermittent walking for two hours in the summer months along three diverse roadways having unique emission characteristics. Measurements of PM2.5, PM10, black carbon (BC), elemental carbon (EC), and organic carbon (OC) were collected. Mixed effect models were used to assess changes in health effects associated with these specific pollutant classes.RESULTS: Minimal associations were observed with lung function measurements and the pollutants measured. Small decreases in BP measurements and rMSSD, and increases in IL-1B and the low frequency to high frequency ratio measured in HRV, were observed with increasing concentrations of PM2.5 EC.CONCLUSIONS: Small, acute changes in cardiovascular and inflammation-related effects of microenvironmental exposures to traffic-related air polution were observed in a group of healthy young adults. The associations were most profound with the diesel-source EC.

Drag De-Orbit Device: A New Standard Re-Entry Actuator for CubeSats

Abstract: With the advent of CubeSats, research in Low Earth Orbit (LEO) becomes possible for universities and small research groups. Only a handful of launch sites can be used, due to geographical and political restrictions. As a result, common orbits in LEO are becoming crowded due to the additional launches made possible by low-cost access to space. CubeSat design principles require a maximum of a 25-year orbital lifetime in an effort to reduce the total number of spacecraft in orbit at any time. Ad…

The 2013 FLEX-US Airborne Campaign at the Parker Tract Loblolly Pine Plantation in North Carolina, USA

Abstract: The first European Space Agency (ESA) and NASA collaboration in an airborne campaign to support ESA’s FLuorescence EXplorer (FLEX) mission was conducted in North Carolina, USA during September-October 2013 (FLEX-US 2013) at the Parker Tract Loblolly Pine (LP) Plantation (Plymouth, NC, USA). This campaign combined two unique airborne instrument packages to obtain simultaneous observations of solar-induced fluorescence (SIF), LiDAR-based canopy structural information, visible through shortwave …