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Comparative developmental toxicity of environmentally relevant oxygenated PAHs
Oxygenated polycyclic aromatic hydrocarbons (OPAHs) are byproducts of combustion and photo-oxidation of parent PAHs. OPAHs are widely present in the environment and pose an unknown hazard to human health. The developing zebrafish was used to evaluate a structurally diverse set of 38 OPAHs for malformation induction, gene expression changes and mitochondrial function. Zebrafish embryos were exposed from 6 to 120 h post fertilization (hpf) to a dilution series of 38 different OPAHs and evaluated for 22 developmental endpoints. AHR activation was determined via CYP1A immunohistochemistry. Phenanthrenequinone (9,10-PHEQ), 1,9-benz-10-anthrone (BEZO), xanthone (XAN), benz(a)anthracene-7,12-dione (7,12-B[a]AQ), and 9,10-anthraquinone (9,10-ANTQ) were evaluated for transcriptional responses at 48 hpf, prior to the onset of malformations. qRT-PCR was conducted for a number of oxidative stress genes, including the glutathione transferase(gst), glutathione peroxidase(gpx), and superoxide dismutase(sod) families. Bioenergetics was assayed to measure in vivo oxidative stress and mitochondrial function in 26 hpf embryos exposed to OPAHs. Hierarchical clustering of the structure-activity outcomes indicated that the most toxic of the OPAHs contained adjacent diones on 6-carbon moieties or terminal, para-diones on multi-ring structures. 5-carbon moieties with adjacent diones were among the least toxic OPAHs while the toxicity of multi-ring structures with more centralized para-diones varied considerably. 9,10-PHEQ, BEZO, 7,12-B[a]AQ, and XAN exposures increased expression of several oxidative stress related genes and decreased oxygen consumption rate (OCR), a measurement of mitochondrial respiration. Comprehensive in vivo characterization of 38 structurally diverse OPAHs indicated differential AHR dependency and a prominent role for oxidative stress in the toxicity mechanisms. - Highlights: • OPAHs are byproducts of combustion present in the environment. • OPAHs pose a largely unknown hazard to human health. • We assayed the developmental toxicology of 39 different OPAHs in zebrafish. • The most toxic OPAHs contained adjacent diones or terminal, para-diones. • AHR dependency varied among OPAHs, and oxidative stress influenced their toxicology.
Synchrotron X-ray microdiffraction (ìXRD) in minerals and environmental research
Abstract not provided
Heterogeneous Nucleation and Growth of Nanoparticles at Environmental Interfaces
Abstract not provided
Exploring Comparative Energy and Environmental Benefits of Virgin, Recycled, and Bio-Derived PET Bottles
Not Available
Impact of environmentally induced fluctuations on quantum mechanically mixed electronic and vibrational pigment states in photosynthetic energy transfer and 2D electronic spectra
Recently, nuclear vibrational contribution signatures in two-dimensional (2D) electronic spectroscopy have attracted considerable interest, in particular as regards interpretation of the oscillatory transients observed in light-harvesting complexes. These transients have dephasing times that persist for much longer than theoretically predicted electronic coherence lifetime. As a plausible explanation for this long-lived spectral beating in 2D electronic spectra, quantum-mechanically mixed electronic and vibrational states (vibronic excitons) were proposed by Christensson et al. [J. Phys. Chem. B 116, 7449 (2012)] and have since been explored. In this work, we address a dimer which produces little beating of electronic origin in the absence of vibronic contributions, and examine the impact of protein-induced fluctuations upon electronic-vibrational quantum mixtures by calculating the electronic energy transfer dynamics and 2D electronic spectra in a numerically accurate manner. It is found that, at cryogenic temperatures, the electronic-vibrational quantum mixtures are rather robust, even under the influence of the fluctuations and despite the small Huang-Rhys factors of the Franck-Condon active vibrational modes. This results in long-lasting beating behavior of vibrational origin in the 2D electronic spectra. At physiological temperatures, however, the fluctuations eradicate the mixing, and hence, the beating in the 2D spectra disappears. Further, it is demonstrated that such electronic-vibrational quantum mixtures do not necessarily play a significant role in electronic energy transfer dynamics, despite contributing to the enhancement of long-lived quantum beating in 2D electronic spectra, contrary to speculations in recent publications.
Environmental and Genetic Factors Regulating Localization of the Plant Plasma Membrane H + -ATPase
Not provided.
Carbonic Anhydrase Mutants in Zea mays Have Altered Stomatal Responses to Environmental Signals
Not provided.
Galactoglycerolipid Lipase PGD1 Is Involved in Thylakoid Membrane Remodeling in Response to Adverse Environmental Conditions in Chlamydomonas
Not provided.
Kernel Density Estimation (KDE) with adaptive bandwidth selection for environmental contours of extreme sea states.
Abstract not provided.
Geographic Assessment of Photovoltaic Module Environmental Degradation Stressors.
Abstract not provided.
Large-Scale Environmental Characteristics of MJOs that Strengthen and Weaken over the Maritime Continent
The characteristics of Madden-Julian Oscillation (MJO) events that strengthen and weaken over the Maritime Continent (MC) are examined using long-term satellite observations and reanalysis datasets. The MJO weakens twice as often as it strengthens over the MC, with weakening MJOs being twice as likely during El Niño years compared to La Niña years and the reverse being true for MJO strengthening events. Weakening MJOs are characterized by large positive sea-surface temperature (SST) and moist-static energy (MSE) anomalies in the southern hemisphere (SH) of the MC compared to MJO strengthening events. These anomalies correspond to more precipitation and stronger upper-level divergence in the SH compared to the NH. The north-south polarity in these variables reflects the seasonal cycle in MJO weakening over the MC. MJOs that approach the MC during the NH winter typically weaken. There is a window during the NH summer and fall in which the MJO almost always strengthens over the MC. This seasonal cycle corresponds to whether the MJO crosses the MC primarily north or south of the equator. The MJO encounters more and taller MC islands when crossing in the SH, which previous results suggest is the likely cause of the frequent weakening. The finding of a seasonal cycle in MJO weakening over the MC complements and extends previous work on the topic and highlights the importance of sampling MJOs throughout the year in future field campaigns designed to study MJO-MC interactions.
A scheme for the uniform mapping and monitoring of earth resources and environmental complexes: An assessment of natural vegetation, environmental, and crop analogs
The author has identified the following significant results. A study was performed to develop and test a procedure for the uniform mapping and monitoring of natural ecosystems in the semi-arid and wood regions of the Sierra-Lahontan and Colorado Plateau areas, and for the estimating of rice crop production in the Northern Great Valley (Ca.) and the Louisiana Coastal Plain. ERTS-1 and high flight and low flight aerial photos were used in a visual photointerpretation scheme to identify vegetation complexes, map acreages, and evaluate crop vigor and stress. Results indicated that the vegetation analog concept is valid; that depending on the kind of vegetation and its density, analogs are interpretable at different levels in the hierarchical classification from second to the fourth level. The second level uses physiognomic growth form-structural criteria, and the fourth level uses floristic or taxonomic criteria, usually at generic level. It is recommended that analog comparisons should be made in relatively small test areas where large homogeneous examples can be found of each analog.
Plan for the uniform mapping of earth resources and environmental complexes from Skylab imagery. Assessment of natural vegetation, environmental, and crop analogs
The author has identified the following significant results. For interpreting a wide range of natural vegetation analogs, S-190A color infrared and the ERTS-1 color composite were consistently more useful than were conventional color or black and white photos. Color infrared was superior for five vegetation analogs while color was superior for only three. The errors in identification appeared to associate more with black and white single band images than with multiband color. For rice crop analogs, spectral and spatial discriminations both contribute to the usefulness of images for data collection. Tests and subjective analyses conducted in this study indicated that the spectral bands exploited in color infrared film were the most useful for agricultural crop analysis. Accuracy of crop identification on any single date of Skylab images was less than that of multidate analysis due to differences in crop calendar, cultural practices used, rice variety, planting date, planting method, water use, fertilization, disease, or mechanical problems.
Investigation of environmental change pattern in Japan: Application of LANDSAT-2 data for understanding environmental changes in the coastal and of shore zone
There are no author-identified significant results in this report.