Search NASA⌕ Search

SEARCH · Search NASA

Results for “Recognizing”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,405 records · Page 78

Elevated levels of plasma uric acid and its relation to hypertension in arsenic-endemic human individuals in Bangladesh

Blood uric acid has been recognized as a putative marker for cardiovascular diseases (CVDs). CVDs are the major causes of arsenic-related morbidity and mortality. However, the association of arsenic exposure with plasma uric acid (PUA) levels in relation to CVDs has not yet been explored. This study for the first time demonstrated the associations of arsenic exposure with PUA levels and its relationship with hypertension. A total of 483 subjects, 322 from arsenic-endemic and 161 from non-endemic areas in Bangladesh were recruited as study subjects. Arsenic concentrations in the drinking water, hair and nails of the study subjects were measured by inductively coupled plasma mass spectroscopy. PUA levels were measured using a colorimetric method. We found that PUA levels were significantly (p < 0.001) higher in males and females living in arsenic-endemic areas than those in non-endemic area. Arsenic exposure (water, hair and nail arsenic) levels showed significant positive correlations with PUA levels. In multiple regression analyses, arsenic exposure levels were found to be the most significant contributors on PUA levels among the other variables that included age, body mass index, blood urea nitrogen, and smoking. There were dose–response relationships between arsenic exposure and PUA levels. Furthermore, diastolic and systolic blood pressure showed significant positive correlations with PUA levels. Finally, the average PUA levels were significantly higher in the hypertensive group than those in the normotensive group in both males and females living in arsenic-endemic areas. These results suggest that arsenic exposure-related elevation of PUA levels may be implicated in arsenic-induced CVDs. - Highlights: • PUA levels were higher in arsenic-endemic subjects than in non-endemic subjects. • Drinking water, hair and nail arsenic showed significant associations with PUA levels. • Drinking water, hair and nail arsenic showed dose–response relationships with PUA. • Arsenic-endemic hypertensive study subjects had elevated levels of PUA. • Increased PUA levels may be implicated in arsenic-induced CVDs.

60 APPLIED LIFE SCIENCES↗

Developmental neurotoxic effects of two pesticides: Behavior and biomolecular studies on chlorpyrifos and carbaryl

In recent times, an increased occurrence of neurodevelopmental disorders, such as neurodevelopmental delays and cognitive abnormalities has been recognized. Exposure to pesticides has been suspected to be a possible cause of these disorders, as these compounds target the nervous system of pests. Due to the similarities of brain development and composition, these pesticides may also be neurotoxic to humans. We studied two different pesticides, chlorpyrifos and carbaryl, which specifically inhibit acetylcholinesterase (AChE) in the nervous system. The aim of the study was to investigate if the pesticides can induce neurotoxic effects, when exposure occurs during a period of rapid brain growth and maturation. The results from the present study show that both compounds can affect protein levels in the developing brain and induce persistent adult behavior and cognitive impairments, in mice neonatally exposed to a single oral dose of chlorpyrifos (0.1, 1.0 or 5 mg/kg body weight) or carbaryl (0.5, 5.0 or 20.0 mg/kg body weight) on postnatal day 10. The results also indicate that the developmental neurotoxic effects induced are not related to the classical mechanism of acute cholinergic hyperstimulation, as the AChE inhibition level (8–12%) remained below the threshold for causing systemic toxicity. The neurotoxic effects are more likely caused by a disturbed neurodevelopment, as similar behavioral neurotoxic effects have been reported in studies with pesticides such as organochlorines, organophosphates, pyrethroids and POPs, when exposed during a critical window of neonatal brain development. - Highlights: • A single neonatal exposure to chlorpyrifos or carbaryl induced developmental neurotoxic effects. • The neurotoxic effects were not caused by acute AChE inhibition. • The neurotoxic effects manifested as altered levels of neuroproteins in the developing brain. • The neurotoxic effects manifested as adult persistent aberrant behavior and cognitive function. • The neurotoxic effects are suggested to be caused by disrupted brain development.

60 APPLIED LIFE SCIENCES↗

Role of extrahepatic UDP-glucuronosyltransferase 1A1: Advances in understanding breast milk-induced neonatal hyperbilirubinemia

Newborns commonly develop physiological hyperbilirubinemia (also known as jaundice). With increased bilirubin levels being observed in breast-fed infants, breast-feeding has been recognized as a contributing factor for the development of neonatal hyperbilirubinemia. Bilirubin undergoes selective metabolism by UDP-glucuronosyltransferase (UGT) 1A1 and becomes a water soluble glucuronide. Although several factors such as gestational age, dehydration and weight loss, and increased enterohepatic circulation have been associated with breast milk-induced jaundice (BMJ), deficiency in UGT1A1 expression is a known cause of BMJ. It is currently believed that unconjugated bilirubin is metabolized mainly in the liver. However, recent findings support the concept that extrahepatic tissues, such as small intestine and skin, contribute to bilirubin glucuronidation during the neonatal period. We will review the recent advances made towards understanding biological and molecular events impacting BMJ, especially regarding the role of extrahepatic UGT1A1 expression. - Highlights: • Breast-feeding can be a factor for the development of neonatal hyperbilirubinemia. • UDP-glucuronosyltransferase (UGT) 1A1 is the sole bilirubin-metabolizing enzyme. • Extrahepatic UGT1A1 plays an important role in bilirubin metabolism. • We discuss the potential mechanism of breast milk-induced neonatal jaundice.

60 APPLIED LIFE SCIENCES↗

Zebrafish embryos as a screen for DNA methylation modifications after compound exposure

Modified epigenetic programming early in life is proposed to underlie the development of an adverse adult phenotype, known as the Developmental Origins of Health and Disease (DOHaD) concept. Several environmental contaminants have been implicated as modifying factors of the developing epigenome. This underlines the need to investigate this newly recognized toxicological risk and systematically screen for the epigenome modifying potential of compounds. In this study, we examined the applicability of the zebrafish embryo as a screening model for DNA methylation modifications. Embryos were exposed from 0 to 72 h post fertilization (hpf) to bisphenol-A (BPA), diethylstilbestrol, 17α-ethynylestradiol, nickel, cadmium, tributyltin, arsenite, perfluoroctanoic acid, valproic acid, flusilazole, 5-azacytidine (5AC) in subtoxic concentrations. Both global and site-specific methylation was examined. Global methylation was only affected by 5AC. Genome wide locus-specific analysis was performed for BPA exposed embryos using Digital Restriction Enzyme Analysis of Methylation (DREAM), which showed minimal wide scale effects on the genome, whereas potential informative markers were not confirmed by pyrosequencing. Site-specific methylation was examined in the promoter regions of three selected genes vasa, vtg1 and cyp19a2, of which vasa (ddx4) was the most responsive. This analysis distinguished estrogenic compounds from metals by direction and sensitivity of the effect compared to embryotoxicity. In conclusion, the zebrafish embryo is a potential screening tool to examine DNA methylation modifications after xenobiotic exposure. The next step is to examine the adult phenotype of exposed embryos and to analyze molecular mechanisms that potentially link epigenetic effects and altered phenotypes, to support the DOHaD hypothesis. - Highlights: • Compound induced effects on DNA methylation in zebrafish embryos • Global methylation not an informative biomarker • Minimal genome wide site specific changes as detected with DREAM • Compound/class specific effects suggested by pyrosequence of specific targets • Zebrafish embryo may be a screening model for epigenetic effects.

60 APPLIED LIFE SCIENCES↗

New frontiers in nanotoxicology: Gut microbiota/microbiome-mediated effects of engineered nanomaterials

It has been recently recognized that the gut microbiota, the community of organisms living within the gastrointestinal tract is an integral part of the human body, and that its genoma (the microbiome) interacts with the genes expressed by the cells of the host organism. Several important physiological functions require the cooperation of microbiota/microbiome, whose alterations play an important role in several human diseases. On this basis, it is probable that microbiota/microbiome may in part be involved in many biological effects of engineered nanomaterials (ENMs). There are still few reports on the possible toxicological effects of ENMs on microbiota/microbiome, and on their possible clinical consequences. Available data suggest that several ENMs, including carbon nanotubes (CNTs), titanium dioxide, cerium dioxide, zinc oxide, nanosilica and nanosilver may affect the microbiota and that clinical disorders such as colitis, obesity and immunological dysfunctions might follow. On the other hand, other ENMs such as iron nanoparticles may show advantages over traditional iron-based supplemental treatment because they do not interfere with the microbiota/microbiome, and some ENM-based therapeutic interventions might be employed for treating intestinal infections, while sparing the microbiota. The final section of the review is focused on the possible future developments of the research in this field: new in vitro and in vivo models, possible biomarkers and new pathophysiological pathways are proposed and discussed, as well as the possibility that metabolic changes following ENMs/microbiota interactions might be exploited as a fingerprint of ENM exposure. The potential toxicological relevance of physico-chemical modifications of ENMs induced by the microbiota is also highlighted. - Highlights: • Interactions between ENMs and microbiota are largely unexplored. • Microbiota probably mediates several ENMs' biological actions. • ENMs/microbiota interactions might provide new specific biomarkers. • ENM/microbiota interactions may be exploited in nanomedicine. • We propose new experimental models and new targets for ENMs/microbiota.

60 APPLIED LIFE SCIENCES↗

Understanding the immunogenicity and antigenicity of nanomaterials: Past, present and future

Nanoparticle immunogenicity and antigenicity have been under investigation for many years. During the past decade, significant progress has been made in understanding what makes a nanoparticle immunogenic, how immune cells respond to nanoparticles, what consequences of nanoparticle-specific antibody formation exist and how they challenge the application of nanoparticles for drug delivery. Moreover, it has been recognized that accidental contamination of therapeutic protein formulations with nanosized particulate materials may contribute to the immunogenicity of this type of biotechnology products. While the immunological properties of engineered nanomaterials and their application as vaccine carriers and adjuvants have been given substantial consideration in the current literature, little attention has been paid to nanoparticle immuno- and antigenicity. To fill in this gap, we herein provide an overview of this subject to highlight the current state of the field, review past and present research, and discuss future research directions. - Highlights: • Most engineered nanomaterials are not immunogenic per se. • Generation of nanoparticle-specific antibody can be T-cell dependent or independent. • Antibodies can be generated to particle core, terminal groups or surface coatings. • Engineered and accidental nanomaterials have distinct contribution to immunogenicity. • Tunable physicochemical properties make each nanoparticle unique.

60 APPLIED LIFE SCIENCES↗

Municipal wastewater affects adipose deposition in male mice and increases 3T3-L1 cell differentiation

Trace concentration of EDs (endocrine disrupting compounds) in water bodies caused by wastewater treatment plant effluents is a recognized problem for the health of aquatic organisms and their potential to affect human health. In this paper we show that continuous exposure of male mice from early development to the adult life (140 days) to unrestricted drinking of wastewater collected from a municipal sewage treatment plant, is associated with an increased adipose deposition and weight gain during adulthood because of altered body homeostasis. In parallel, bisphenol A (BPA) at the administration dose of 5 μg/kg/body weight, shows an increasing effect on total body weight and fat mass. In vitro, a solid phase extract (SPE) of the wastewater (eTW), caused stimulation of 3T3-L1 adipocyte differentiation at dilutions of 0.4 and 1 % in the final culture medium which contained a concentration of BPA of 40 nM and 90 nM respectively. Pure BPA also promoted adipocytes differentiation at the concentration of 50 and 80 μM. BPA effect in 3T3-L1 cells was associated to the specific activation of the estrogen receptor alpha (ERα) in undifferentiated cells and the estrogen receptor beta (ERβ) in differentiated cells. BPA also activated the Peroxisome Proliferator Activated Receptor gamma (PPARγ) upregulating a minimal 3XPPARE luciferase reporter and the PPARγ-target promoter of the aP2 gene in adipose cells, while it was not effective in preadipocytes. The pure estrogen receptor agonist diethylstilbestrol (DES) played an opposite action to that of BPA inhibiting PPARγ activity in adipocytes, preventing cell differentiation, activating ERα in preadipocytes and inhibiting ERα and ERβ regulation in adipocytes. The results of this work show that the drinking of chemically-contaminated wastewater promotes fat deposition in male mice and that EDs present in sewage are likely responsible for this effect through a nuclear receptor-mediated mechanism. - Highlights: • Sewage watewaters (TW) sampled from a Municipal Treatment Sewage Plant are biologically active in mice and in vitro. • In male mice TW promotes an increase in adipose mass deposition following exposure from foetal to adult life. A similar effect is produced by BPA. • The expression of key genes of the adipose metabolism is increased in epidydimal fat both by TW and BPA. • An extract from the TW which concentrated the contained chemicals by a factor of 1000, is able to stimulate 3T3-L1 adipocyte differentiation. • The major chemicals contained in the TW, bisphenol A and nonylphenol, are able to promote adipocyte differentiation at the low environmentally relevant doses as are found in the TW.

60 APPLIED LIFE SCIENCES↗

Nrf2 activation ameliorates cytotoxic effects of arsenic trioxide in acute promyelocytic leukemia cells through increased glutathione levels and arsenic efflux from cells

Carnosic acid (CA), a phenolic diterpene isolated from Rosmarinus officinalis, has been shown to activate nuclear transcription factor E2-related factor 2 (Nrf2), which plays a central role in cytoprotective responses to oxidative and electrophilic stress. Recently, the Nrf2-Kelch ECH associating protein 1 (Keap1) pathway has been associated with cancer drug resistance attributable to modulation of the expression and activation of antioxidant and detoxification enzymes. However, the exact mechanisms by which Nrf2 activation results in chemoresistance are insufficiently understood to date. This study investigated the mechanisms by which the cytotoxic effects of arsenic trioxide (ATO), an anticancer drug, were decreased in acute promyelocytic leukemia cells treated with CA, a typical activator of Nrf2 used to stimulate the Nrf2/Keap1 system. Our findings suggest that arsenic is non-enzymatically incorporated into NB4 cells and forms complexes that are dependent on intracellular glutathione (GSH) concentrations. In addition, the arsenic complexes are recognized as substrates by multidrug resistance proteins and subsequently excreted from the cells. Therefore, Nrf2-associated activation of the GSH biosynthetic pathway, followed by increased levels of intracellular GSH, are key mechanisms underlying accelerated arsenic efflux and attenuation of the cytotoxic effects of ATO. - Highlights: • Nrf2 activation attenuates the effect of arsenic trioxide to acute promyelocytic leukemia cells. • The sensitivity of arsenic trioxide to NB4 cells was dependent on efflux rate of arsenic. • Activation of the GSH biosynthesis is essential in Nrf2-regulated responses for arsenic efflux.

60 APPLIED LIFE SCIENCES↗

Systematic network assessment of the carcinogenic activities of cadmium

Cadmium has been defined as type I carcinogen for humans, but the underlying mechanisms of its carcinogenic activity and its influence on protein-protein interactions in cells are not fully elucidated. The aim of the current study was to evaluate, systematically, the carcinogenic activity of cadmium with systems biology approaches. From a literature search of 209 studies that performed with cellular models, 208 proteins influenced by cadmium exposure were identified. All of these were assessed by Western blotting and were recognized as key nodes in network analyses. The protein-protein functional interaction networks were constructed with NetBox software and visualized with Cytoscape software. These cadmium-rewired genes were used to construct a scale-free, highly connected biological protein interaction network with 850 nodes and 8770 edges. Of the network, nine key modules were identified and 60 key signaling pathways, including the estrogen, RAS, PI3K-Akt, NF-κB, HIF-1α, Jak-STAT, and TGF-β signaling pathways, were significantly enriched. With breast cancer, colorectal and prostate cancer cellular models, we validated the key node genes in the network that had been previously reported or inferred form the network by Western blotting methods, including STAT3, JNK, p38, SMAD2/3, P65, AKT1, and HIF-1α. These results suggested the established network was robust and provided a systematic view of the carcinogenic activities of cadmium in human. - Highlights: • A cadmium-influenced network with 850 nodes and 8770 edges was established. • The cadmium-rewired gene network was scale-free and highly connected. • Nine modules were identified, and 60 key signaling pathways related to cadmium-induced carcinogenesis were found. • Key mediators in the network were validated in multiple cellular models.

60 APPLIED LIFE SCIENCES↗

UDCA and CDCA alleviate 17α-ethinylestradiol-induced cholestasis through PKA-AMPK pathways in rats

Estrogen-induced cholestasis, known as intrahepatic cholestasis of pregnancy (ICP), is an estrogen-related liver disease that is widely recognized as female or pregnancy-specific. Our previous findings showed that the synthetic estrogen, 17α-ethinylestradiol (EE), induced cholestatic injury through ERK1/2-LKB1-AMP-activated protein kinase (AMPK) signaling pathway and its mediated suppression of farnesoid X receptor (FXR). To investigate the role played by bile acids in EE-induced cholestasis, we evaluated the effects of chenodeoxycholic acid (CDCA), ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) on sandwich cultured rat primary hepatocytes (SCRHs) and an in vivo rat model. Our results showed that, both CDCA and UDCA significantly induced time- and concentration-dependent reduction in AMPK phosphorylation in SCRHs. Despite having different effects on FXR activation, CDCA and UDCA both inhibited EE-induced AMPK activation, accompanied with the up-regulation of FXR and its downstream bile acid transporters. However, although DCA activates FXR and induces SHP, it was unable to alleviate EE-induced FXR suppression and further aggravated EE-induced cholestasis. We further demonstrated that both CDCA and UDCA, but not DCA, activated cyclic AMP dependent protein kinase (PKA) in SCRHs and the livers of male rats (8 weeks old) liver. Furthermore, PKA antagonist, H89, blocked the AMPK inhibition by CDCA and UDCA, and pharmacological and genetic activation of PKA suppressed EE-induced AMPK activation and its downstream effects. Collectively, these results suggest that CDCA and UDCA protect against estrogen-induced cholestatic injury via PKA signaling pathway and up-regulation of EE-suppressed FXR, which suggests a potential therapeutic target for ICP. - Highlights: • AMPK is involved in cholestatic liver injury with bile acid dysregulation. • CDCA and UDCA inhibit the phosphorylation of AMPK and alleviate estrogen-induced cholestasis. • PKA activation contributes to the CDCA- and UDCA-induced protective effects. • FXR up-regulation may be critical for improvement of cholestasis.

54 ENVIRONMENTAL SCIENCES↗

Ultrafine carbon particles promote rotenone-induced dopamine neuronal loss through activating microglial NADPH oxidase

Background: Atmospheric ultrafine particles (UFPs) and pesticide rotenone were considered as potential environmental risk factors for Parkinson's disease (PD). However, whether and how UFPs alone and in combination with rotenone affect the pathogenesis of PD remains largely unknown. Methods: Ultrafine carbon black (ufCB, a surrogate of UFPs) and rotenone were used individually or in combination to determine their roles in chronic dopaminergic (DA) loss in neuron-glia, and neuron-enriched, mix-glia cultures. Immunochemistry using antibody against tyrosine hydroxylase was performed to detect DA neuronal loss. Measurement of extracellular superoxide and intracellular reactive oxygen species (ROS) were performed to examine activation of NADPH oxidase. Genetic deletion and pharmacological inhibition of NADPH oxidase and MAC-1 receptor in microglia were employed to examine their role in DA neuronal loss triggered by ufCB and rotenone. Results: In rodent midbrain neuron-glia cultures, ufCB and rotenone alone caused neuronal death in a dose-dependent manner. In particularly, ufCB at doses of 50 and 100 μg/cm{sup 2} induced significant loss of DA neurons. More importantly, nontoxic doses of ufCB (10 μg/cm{sup 2}) and rotenone (2 nM) induced synergistic toxicity to DA neurons. Microglial activation was essential in this process. Furthermore, superoxide production from microglial NADPH oxidase was critical in ufCB/rotenone-induced neurotoxicity. Studies in mix-glia cultures showed that ufCB treatment activated microglial NADPH oxidase to induce superoxide production. Firstly, ufCB enhanced the expression of NADPH oxidase subunits (gp91{sup phox}, p47{sup phox} and p40{sup phox}); secondly, ufCB was recognized by microglial surface MAC-1 receptor and consequently promoted rotenone-induced p47{sup phox} and p67{sup phox} translocation assembling active NADPH oxidase. Conclusion: ufCB and rotenone worked in synergy to activate NADPH oxidase in microglia, leading to oxidative damage to DA neurons. Our findings delineated the potential role of ultrafine particles alone and in combination with pesticide rotenone in the pathogenesis of PD. - Graphical abstract: Ultrafine particles and rotenone synergistically induce the assembly of active form NADPH oxidase complex in microglia inducing oxidative damage to dopamine neurons. - Highlights: • Ultrafine carbon black promotes dopaminergic neuronal loss induced by rotenone. • The role and underlying mechanism of ultrafine particles in the pathogenesis of PD • NADPH oxidase is a potential therapeutic target of Parkinson's disease.

60 APPLIED LIFE SCIENCES↗

HSP90 and pCREB alterations are linked to mancozeb-dependent behavioral and neurodegenerative effects in a marine teleost

The pesticide mancozeb (mz) is recognized as a potent inducer of oxidative stress due to its ability to catalyze the production of reactive oxygen species plus inhibiting mitochondrial respiration thus becoming an environmental risk for neurodegenerative diseases. Despite numerous toxicological studies on mz have been directed to mammals, attention on marine fish is still lacking. Thus, it was our intention to evaluate neurobehavioral activities of ornate wrasses (Thalassoma pavo) exposed to 0.2 mg/l of mz after a preliminary screening test (0.07–0.3 mg/l). Treated fish exhibited an evident (p < 0.001) latency to reach T-maze arms (> 1000%) while exploratory attitudes (total arm entries) diminished (− 50%; p < 0.05) versus controls during spontaneous exploration tests. Moreover, they showed evident enhancements (+ 111%) of immobility in the cylinder test. Contextually, strong (− 88%; p < 0.01) reductions of permanence in light zone of the Light/Dark apparatus along with diminished crossings (− 65%) were also detected. Conversely, wrasses displayed evident enhancements (160%) of risk assessment consisting of fast entries in the dark side of this apparatus. From a molecular point of view, a notable activation (p < 0.005) of the brain transcription factor pCREB occurred during mz-exposure. Similarly, in situ hybridization supplied increased HSP90 mRNAs in most brain areas such as the lateral part of the dorsal telencephalon (Dl; + 68%) and valvula of the cerebellum (VCe; + 35%) that also revealed evident argyrophilic signals. Overall, these first indications suggest a possible protective role of the early biomarkers pCREB and HSP90 against fish toxicity. - Highlights: • Fish exposed to mancozeb exhibited an evident latency to reach T-maze arms. • Mancozeb caused immobility and reduction of explorative attitudes. • Fish exposed to mancozeb showed anxiogenic performances in the Light/Dark apparatus. • The brain of fish exposed to mancozeb supplied pCREB plus HSP90 mRNA up-regulations. • Some brain areas of fish exposed to mancozeb revealed an evident neurodegeneration.

60 APPLIED LIFE SCIENCES↗

Comparison of the toxicity of sintered and unsintered indium-tin oxide particles in murine macrophage and epidermal cells

Indium-tin oxide (ITO) is used to produce flat panel displays and several other technology products. Composed of 90% indium oxide (In{sub 2}O{sub 3}) and 10% tin oxide (SnO{sub 2}) by weight, ITO is synthesized under conditions of high heat via a process known as sintering. Indium lung disease, a recently recognized occupational illness, is characterized by pulmonary alveolar proteinosis, fibrosis, and emphysema. Murine macrophage (RAW 264.7) and epidermal (JB6) cells stably transfected with AP-1 to study tumor promoting potential, were used to differentiate between the toxicological profiles of sintered ITO (SITO) and unsintered mixture (UITO). We hypothesized that sintering would play a key role in free radical generation and cytotoxicity. Exposure of cells to both UITO and SITO caused a time and dose dependent decrease of the viability of cells. Intracellular ROS generation was inversely related to the dose of both UITO and SITO, a direct reflection of the decreased number of viable RAW 264.7 and JB6/AP-1 cells observed at higher concentrations. Electron spin resonance showed significantly increased hydroxyl radical (·OH) generation in cells exposed to UITO compared to SITO. This is different from LDH release, which showed that SITO caused significantly increased damage to the cell membrane compared to UITO. Lastly, the JB6/AP-1 cell line did not show activation of the AP-1 pathway. Our results highlight both the differences in the mechanisms of cytotoxicity and the consistent adverse effects associated with UITO and SITO exposure. - Highlights: • Sintered indium-tin oxide significantly impacts cellular viability and LDH release. • Unsintered indium-tin oxide impacts free radical production and DNA damage. • Indium compounds do not activate the AP-1 pathway.

60 APPLIED LIFE SCIENCES↗

Systematic developmental neurotoxicity assessment of a representative PAH Superfund mixture using zebrafish

Superfund sites often consist of complex mixtures of polycyclic aromatic hydrocarbons (PAHs). It is widely recognized that PAHs pose risks to human and environmental health, but the risks posed by exposure to PAH mixtures are unclear. Here, we constructed an environmentally relevant PAH mixture with the top 10 most prevalent PAHs (SM10) from a Superfund site derived from environmental passive sampling data. Using the zebrafish model, we measured body burden at 48 hours post fertilization (hpf) and evaluated the developmental and neurotoxicity of SM10 and the 10 individual constituents at 24 hours post fertilization (hpf) and 5 days post fertilization (dpf). Zebrafish embryos were exposed from 6 to 120 hpf to (1) the SM10 mixture, (2) a variety of individual PAHs: pyrene, fluoranthene, retene, benzo[a]anthracene, chrysene, naphthalene, acenaphthene, phenanthrene, fluorene, and 2-methylnaphthalene. We demonstrated that SM10 and only 3 of the individual PAHs were developmentally toxic. Subsequently, we constructed and exposed developing zebrafish to two sub-mixtures: SM3 (comprised of 3 of the developmentally toxicity PAHs) and SM7 (7 non-developmentally toxic PAHs). We found that the SM3 toxicity profile was similar to SM10, and SM7 unexpectedly elicited developmental toxicity unlike that seen with its individual components. The results demonstrated that the overall developmental toxicity in the mixtures could be explained using the general concentration addition model. To determine if exposures activated the AHR pathway, spatial expression of CYP1A was evaluated in the 10 individual PAHs and the 3 mixtures at 5 dpf. Results showed activation of AHR in the liver and vasculature for the mixtures and some individual PAHs. Embryos exposed to SM10 during development and raised in chemical-free water into adulthood exhibited decreased learning and responses to startle stimulus indicating that developmental SM10 exposures affect neurobehavior. Collectively, these results exemplify the utility of zebrafish to investigate the developmental and neurotoxicity of complex mixtures.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Part 1: Tracing Russian VX to its synthetic routes by multivariate statistics of chemical attribution signatures

Chemical attribution signatures (CAS) associated with different synthetic routes used for the production of Russian VX (VR) were identified here. The goal of the study was to retrospectively determine the production method employed for an unknown VR sample. Six different production methods were evaluated, carefully chosen to include established synthetic routes used in the past for large scale production of the agent, routes involving general phosphorus-sulfur chemistry pathways leading to the agent, and routes whose main characteristic is their innate simplicity in execution. Two laboratories worked in parallel and synthesized a total of 37 batches of VR via the six synthetic routes following predefined synthesis protocols. The chemical composition of impurities and byproducts in each route was analyzed by GC/MS-EI and 49 potential CAS were recognized as important markers in distinguishing these routes using Principal Component Analysis (PCA). The 49 potential CAS included expected species based on knowledge of reaction conditions and pathways but also several novel compounds that were fully identified and characterized by a combined analysis that included MS-CI, MS-EI and HR-MS. The CAS profiles of the calibration set were then analyzed using partial least squares discriminant analysis (PLS-DA) and a cross validated model was constructed. The model allowed the correct classification of an external test set without any misclassifications, demonstrating the utility of this methodology for attributing VR samples to a particular production method. This work is part one of a three-part series in this Forensic VSI issue of a Sweden-United States collaborative effort towards the understanding of the CAS of VR in diverse batches and matrices. This part focuses on the CAS in synthesized batches of crude VR and in the following two parts of the series the influence of food matrices on the CAS profiles are investigated.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Method development for comprehensive extraction and analysis of marine toxins: Liquid-liquid extraction and tandem liquid chromatography separations coupled to electrospray tandem mass spectrometry

Toxins from biological sources are recognized as potential chemical weapon threats, with saxitoxin and ricin listed by the chemical weapons convention (CWC) as schedule one agents (CWC reference). These two toxins represent a metabolite (saxitoxin) and protein (ricin) from algal and plant sources, respectively. An array of toxins have been listed as "select agents" by the Health and Human Services (HHS) select agent program, including ricin, abrin, saxitoxin, tetrodotoxin, specific paralytic alpha conotoxin peptides, T-2 toxin, diacetoxyscirpenols, botulinum toxins, and staphylococcal enterotoxins [1]. The quantities of these toxins dictate whether they are considered select agents with federal oversight of their storage and use. While this list captures some of the naturally occurring toxins that may pose a threat to the public, there are a number of other naturally occurring toxins that may also be a concern.

biodetection↗

Thermal analysis of calcium sulfate dihydrate sources used to manufacture gypsum wallboard

Gypsum wallboard has been used for over 100 years as a barrier to the spread of fire in residential and commercial structures. The gypsum molecule, CaSO 4 ·2H 2 O, provides two crystalline waters that are released upon heating providing an endothermic effect. Manufacturers have recognized that the source of the gypsum ore is a factor that affects all aspects of its performance; thus, it is hypothesized that the impurities present in the gypsum ore are the causes of the performance differences. Differential Thermal Analysis/Thermogravimetric Analysis (DTA/TGA) and X-ray Diffraction (XRD) were used in this paper to compare and characterize samples of gypsum ore representing sources of natural, synthetic from a Flue Gas Desulfurization process (FGD) and blends thereof. The hemihydrate phase of representative natural, FGD, and reagent grade calcium sulfate were rehydrated with distilled water and evaluated by DTA/TGA. Analysis of the data shows distinct areas of similarity separated by the conversion to anhydrite ~250 °C. Compositional reconstructions based on DTA/TGA and XRD data were compared and although, the results were comparable, the DTA/TGA suggests thermally active compounds that were not detected by XRD. Anhydrite, silica and halite were reported by XRD but were not thermally reactive in the temperature range evaluated by DTA/TGA (ambient to 1050 °C). Finally, the presence of carbonate compounds (e.g., calcite and dolomite) were indicated by XRD and estimated from the thermal decomposition reaction ~700 °C.

36 MATERIALS SCIENCE↗

The state of advanced measurement and verification technology and industry application

With the expansion of advanced metering and increased use of energy analytics tools, the energy efficiency community has begun to explore the application of advanced measurement and verification (or ‘M & V 2.0') technologies. Current literature recognizes their promise, but does not offer in-depth assessment of technical underpinnings. Here, this paper assesses the state of the technology and its application. Sixteen commercially available technologies were characterized and combined with a national review of their use.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗