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Ionizing radiation is a major environmental variable for cells on Earth, and so organisms have adapted to either prevent or to repair damages caused by it, primarily from the appearance and accumulation of reactive oxygen species (ROS). In this study, we measured the differential gene expression in Deinococcus radiodurans UWO298 cultures deprived of background ionizing radiation (IR) while growing 605 m underground at the Waste Isolation Pilot Plant (WIPP), reducing the dose rate from 72.1 to 0.9 nGy h(-1) from control to treatment, respectively. This reduction in IR dose rate delayed the entry into the exponential phase of the IR-shielded cultures, resulting in a lower biomass accumulation for the duration of the experiment. The RNASeq-based transcriptome analysis showed the differential expression of 0.2 and 2.7% of the D. radiodurans genome after 24 and 34 h of growth in liquid culture, respectively. Gene expression regulation after 34 h was characterized by the downregulation of genes involved in folding newly synthesized and denatured/misfolded proteins, in the assimilation of nitrogen for amino acid synthesis and in the control of copper transport and homeostasis to prevent oxidative stress. We also observed the upregulation of genes coding for proteins with transport and cell wall assembly roles. These results show that D. radiodurans is sensitive to the absence of background levels of ionizing radiation and suggest that its transcriptional response is insufficient to maintain optimal growth. United States Department of Energy (DOE) Office of Environmental ManagementUnited States Department of Energy (DOE) [DE-EM0002423] Published version These results are based upon work supported by the United States Department of Energy (DOE) Office of Environmental Management under award number DE-EM0002423. This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government or any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe on privately owned rights. Reference herein to any specific commercial product, process, or service by trade names, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement. The views and the opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

We present the development of an eye-safe, invisible, stand-off technique designed for the detection of target chemicals (such as explosives) in a single “snapshot” frame. Broadband Fabry-Perot quantum cascade lasers (FP-QCLs) in the wavelength range of 7 to 12 microns, are directed to a target to interrogate its spectral features. The “backscatter” return signals from target chemicals are spectrally discriminated by an LWIR spatial heterodyne spectrometer (SHS). The SHS offers high throughput and full spectral coverage in each single frame from an IR imaging array. This presentation will cover the performance and optimization of FP-QCLs for this broadband spectroscopic application. We will also discuss the operation and processing of SHS images to extract spectral information. Finally, we will present results of measurements using specific analytes to demonstrate the application of the method to stand-off detection of targets such as explosives and other chemical threats.

Studies of the biological effects of low-level and below-background radiation are important in understanding the potential effects of radiation exposure in humans. To study this issue we exposed the nematode Caenorhabditis elegans to average background and below-background radiation levels. Two experiments were carried-out in the underground radiation biology laboratory at the Waste Isolation Pilot Plant (WIPP) in New Mexico USA. The first experiment used naïve nematodes with data collected within 1 week of being placed underground. The second experiment used worms that were incubated for 8 months underground at below background radiation levels. Nematode eggs were placed in two incubators, one at low radiation (ca.15.6 nGy/hr) and one supplemented with 2 kg of natural KCl (ca. 67.4 nGy/hr). Phenotypic variables measured were: (1) egg hatching success (2) body size from larval development to adulthood, (3) developmental time from egg to egg laying adult, and (4) egg laying rate of young adult worms. Transcriptome analysis was performed on the first experiment on 72 h old adult worms. Within 72 h of being underground, there was a trend of increased egg-laying rate in the below-background radiation treatment. This trend became statistically significant in the group of worms exposed to below-background radiation for 8 months. Worms raised for 8 months in these shielded conditions also had significantly faster growth rates during larval development. Transcriptome analyses of 72-h old naïve nematode RNA showed significant differential expression of genes coding for sperm-related proteins and collagen production. In the below-background radiation group, the genes for major sperm protein (msp, 42% of total genes) and sperm-related proteins (7.5%) represented 49.5% of the total genes significantly up-regulated, while the majority of down-regulated genes were collagen (col, 37%) or cuticle-related (28%) genes. RT-qPCR analysis of target genes confirmed transcriptomic data. These results demonstrate that exposure to below-background radiation rapidly induces phenotypic and transcriptomic changes in C. elegans within 72 h of being brought underground.

Optically-active constituents vary over short time and space scales in coastal waters, and they are impacted by a variety of complex, inter-related forcing processes. As part of the Integrated Coastal Bio-Optical Dynamics (ICoBOD) project, we conducted a field campaign in Mississippi Sound in the northern Gulf of Mexico during spring 2018 to examine the impact of the passage of atmospheric and tidal fronts on fine-scale physical and bio-optical property distributions in a shallow, dynamic, coastal environment. During a 25-day experiment, we deployed eight moorings over a roughly 7 &times, 7 km box encompassing a frontal zone, to collect a time series of physical and bio-optical measurements. We describe changes in diver visibility related to the passage of a short-duration, high-turbidity surface plume and nepheloid layer development/decay during a tidal cycle. Maximum nepheloid layer development was observed during low tide and lasted about 9&ndash, 12 hours. The strongest turbidity signal extended about 4&ndash, 5 m above the bottom (approximately half of the water column), although anomalously elevated values were observed all the way to the surface. In addition, high-resolution (50 m) hydrodynamic model simulations provide insight into the frontal dynamics and aid interpretation of the observed patterns. Mooring observations confirmed model-predicted heat flux changes associated with the passage of an atmospheric cold front.

The global optimal solution (GOS) has proven to be very accurate for deriving water surface velocities from contemporaneous image pairs, but previous studies have used shore-based radars or satellite measurements with resolutions on the order of a kilometer or tens of meters to establish this. In contrast, the objective of this paper is to derive a GOS velocity field from infrared (IR) (3–5 $\mu \text{m}$ ) images having a 1-m pixel size. Because IR images can frequently exhibit a low signal-to-noise ratio, a newly developed GOS technique with a local similarity metric is used to retrieve velocities from such low-contrast data sets. To demonstrate the utility of this new method, we use airborne data collected in the tidal Potomac River over 11 days and spatially varying flood, ebb, and slack conditions. The resulting GOS-derived velocity estimates are compared against acoustic Doppler current profiler (ADCP) measurements taken simultaneously with the airborne collections. Velocity magnitudes and directions are found to have GOS versus ADCP correlations of 0.93 and 0.99, respectively. This high correlation suggests that the GOS technique may be applicable to a variety of lower contrast imagery that can now be collected by a low-altitude remotely controlled aircraft.

A pair of time-lagged satellite images of surface algae in the Great Barrier Reef lagoon is used to investigate characteristics of the horizontal velocity field at a spatial resolution as small as 4 m. A distinctive feature is the occurrence of surface patches that are relatively clear of algae and which grow in size. These patches are interpreted as resulting from the horizontally diverging motion associated with boils. The surface divergence in such boils can be as large as ~ 0.01 s −1 , as deduced directly from the imagery. Overall, root-mean-squared values of divergence, vorticity, and strain rate are 45, 58, and 170, respectively, when normalized by the Coriolis parameter. By observing the algae and its fluid environment simultaneously, the analysis thus provides a glimpse of how underlying hydrodynamic processes help shape the distribution of surface algae — under the calm winds that favor the formation of dense surface aggregations.

In this study, we compared removal of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in two wastewater treatment systems fed with the same primary effluent: a conventional wastewater treatment system (consisting of a trickling filter followed by an activated sludge process) versus an algal-based system, employing an extremophilic alga, Galdieria sulphuraria. Our results demonstrated that the algal system can reduce concentrations of erythromycin- and sulfamethoxazole-resistant bacteria in the effluent more effectively than the conventional treatment system. A decreasing trend of total bacteria and ARGs was observed in both the treatment systems. However, the relative ratio of most ARGs (qnrA, qnrB, qnrS, sul1) and intI1 in the surviving bacteria increased in the conventional system; whereas, the algal system reduced more of the relative abundance of qnrA, qnrS, tetW and intⅠ1 in the surviving bacteria. The role of bacteriophages in horizontal gene transfer (HGT) of ARGs in the two systems was indicated by a positive correlation between ARG absolute abundance in bacteriophage and ARG relative abundance in the bacteria. Four of the five detectable genes (qnrS, tetW, sul1 and intI1) were significantly reduced in the algal system in bacteriophage phase which signified a decrease in phage-mediated ARG transfer in the algal system. Results of this study demonstrate the feasibility of the algal-based wastewater treatment system in decreasing ARGs and ARB and in minimizing the spread of antibiotic resistance to the environment.

This paper explores the use of infrared remote sensing methods to examine submesoscale eddies that recur downstream of a deep-water island (Santa Catalina, CA). Data were collected using a mid-wave infrared camera deployed on an aircraft flown at an altitude of 3.7 km, and research boats made nearly simultaneous measurements of temperature and current profiles. Structure within the thermal field is generally adequate as a tracer of surface fluid motions, though the imagery needs to be processed in a novel way to preserve the smallest-scale tracer patterns. In the case we focus on, the eddy is found to have a thermal signature of about 1 km in diameter and a cyclonic swirling flow. Vorticity is concentrated over a smaller area of about 0.5 km in diameter. The Rossby number is 27, indicating the importance of the centrifugal force in the dynamical balance of the eddy. By approximating the eddy as a Rankine vortex, an estimate of upward doming of the thermocline (about 14 m at the center) is obtained that agrees qualitatively with the in-water measurements. Analysis also shows an outward radial flow that creates areas of convergence (sinking flow) along the perimeter of the eddy. The imagery also reveals areas of localized vertical mixing within the eddy thermal perimeter, and an area of external azimuthal banding that likely arises from flow instability.

Natural ionizing background radiation has exerted a constant pressure on organisms since the first forms of life appeared on Earth, so that cells have developed molecular mechanisms to avoid or repair damages caused directly by radiation or indirectly by radiation-induced reactive oxygen species (ROS). In the present study, we investigated the transcriptional effect of depriving Shewanella oneidensis cultures of background levels of radiation by growing the cells in a mine 655 m underground, thus reducing the dose rate from 72.1 to 0.9 nGy h-1 from control to treatment, respectively. RNASeq transcriptome analysis showed the differential expression of 4.6 and 7.6% of the S. oneidensis genome during early- and late-exponential phases of growth, respectively. The greatest change observed in the treatment was the downregulation of ribosomal proteins (21% of all annotated ribosomal protein genes during early- and 14% during late-exponential) and tRNA genes (14% of all annotated tRNA genes in early-exponential), indicating a marked decrease in protein translation. Other significant changes were the upregulation of membrane transporters, implying an increase in the traffic of substrates across the cell membrane, as well as the up and downregulation of genes related to respiration, which could be interpreted as a response to insufficient oxidants in the cells. In other reports, there is evidence in multiple species that some ROS not just lead to oxidative stress, but act as signaling molecules to control cellular metabolism at the transcriptional level. Consistent with these reports, several genes involved in the metabolism of carbon and biosynthesis of amino acids were also regulated, lending support to the idea of a wide metabolic response. Our results indicate that S. oneidensis is sensitive to the withdrawal of background levels of ionizing radiation and suggest that a transcriptional response is required to maintain homeostasis and retain normal growth.

Quantifying active and residual whitecap fractions separately can improve parameterizations of air-sea fluxes associated with breaking waves. We use data from a multi-instrumental field campaign on FLoating Instrument Platform (FLIP) to simultaneously capture the signatures of active and residual whitecaps at visible, infrared (IR) and microwave wavelengths using, respectively, video camera, mid-IR camera, and a radiometer at 10 GHz. We present results from processing and analyzing IR images and correlating this information with radiometric time series of brightness temperature at horizontal and vertical polarizations TBH and TBV. The results provide evidence that breaking crests and decaying foam appear in mid-IR as bright and dark pixels clearly distinguishing active from residual whitecaps. We quantify the durations of whitecap lifetime stages from the IR images and identify their corresponding signatures in TB time series. Results show that TBH and TBV vary in phase during the active and in anti-phase during the residual whitecap stages. A methodology to distinguish active and residual whitecaps in radiometric time series without a priori IR information has been developed and verified with corresponding IR and video images. The method uses the degree of polarization P (the ratio between the sum and difference of TBV and TBH) to capture whitecaps as prominent spikes. The maximum and zero-crossing of the first derivative of P serve to identify the presence of active whitecaps, while the minimum of dP marks the transition from active to residual whitecap stage. The findings have implications for radiometric measurements of active and total whitecap fractions. This article is protected by copyright. All rights reserved.

An airborne scanning topographic lidar is shown to detect a local sea-level change induced by tidally forced flow over a 60-m-deep estuarine sill. As the flow speeds up over the sill, the sea level can be expected to decrease to conserve total flow energy according to the Bernoulli equation. The measurements resolve this decrease, showing a drop in sea level over the sill crest of about 0.1 m near the start of flood tide, increasing to about 0.25 m an hour later. These values are shown to be consistent with the Bernoulli effect, but only if a fraction (about 60%) of the upstream water column flows over the sill. By inference, the remaining fraction must deflect horizontally around the sill to flow through an adjacent channel, an effect consistent with laboratory studies of stratified flow past a three-dimensional (3-D) barrier with a gap. The lidar measurements, therefore, provide some insight into the 3-D flow response.

All organisms on earth grow under the influence of a natural and relatively constant dose of ionizing radiation referred to as background radiation, and so cells have different mechanisms to prevent the accumulation of damage caused by its different components. However, current knowledge of the deleterious effects of radiation on cells is based on the exposure to acute and high or to chronic, above background doses of radiation and therefore is not appropriate to explain the cellular and biochemical mechanisms that cells employ to sense and respond to chronic below-background levels. Studies at below-background radiation doses can provide insight into the biological role of radiation, as suggested by several examples of what appears to be a stress response in cells grown at doses that range from 10 to 70 times lower than background. Here we discuss some of the technical constraints to shield cells from radiation to below-background levels, as well as different approaches used to detect and measure responses to such unusual environmental conditions. Then we present data from Shewanella oneidensis and Deinococcus radiodurans experiments that show how two taxonomically distant bacterial species sense and respond to unnaturally low levels of radiation. In brief, we grew S. oneidensis and D. radiodurans in liquid culture at dose rates of 62.75 (control) and 0.89 (treatment) nGy hr-1 (including radon) for up to 72 hours and measured cell density and the expression of stress-related genes. Our results suggest that a stress response is triggered in the absence of normal levels of radiation.

The surface temperature field induced by a turbulent buoyant jet, discharging upwards into shallow water and impinging on the water surface, is examined for the case of a power-plant cooling-water outfall off the southern California coast. The data, acquired using an airborne infrared camera, capture the evolution of turbulent-scale structure, as well as the advection of larger-scale patterns that can be used to infer the surface velocity. Some limited in-water measurements were also made. When the ambient, or receiving, water is relatively stagnant, the buoyant fluid moves nearly symmetrically outward from the impingement zone, and both the thermal and velocity fields decay over a radial distance of several tens of meters. Flow in this symmetric case appears to remain supercritical into the far-field, which differs from a recent numerical modeling study that predicts a near-field hydraulic jump. Within the plume, the data show an expanding set of thermal bands, similar to ring-like structures found in laboratory studies of a buoyant vertical jet having a stable near-field. In the presence of an alongshore current, both the plume and thermal bands become stretched out in the downstream direction; but this effect can be accounted for, and the thermal structure made symmetrical, by using an approximate two-dimensional model of the flow field. Characteristics of the observed thermal bands are compared against three ring-creation mechanisms proposed in the literature (jet vortex instability, horizontal shear instability, and internal bore formation), but the present dataset is insufficient to discriminate amongst them.

Re-use of wastewater nutrients may enhance sustainability of algal biofuels. However wastewaters harbor complex microbial consortia including enteric viruses. Appropriate evaluation protocols are required to understand and monitor associated health risks. Commonly, virus viability is assessed by host specific plaque assays. Assays' accuracy is critically dependent on the assumption that viral particles are uniformly distributed in samples. Complex charged and hydrophobic loci on algal cells may affect this assumption. We verified the likelihood for Nannochloropsis salina to affect partitioning of viruses between planktonic and attached compartments by employing a common test surrogate for enteric viruses, the MS2 bacteriophage. Firstly, we verified the immediate (within 30 min) partitioning of spiked virus between supernatant (planktonic) and centrifuged algal pellet (fixed compartment) for algae of variable ages, and thus physiological states, grown in standard medium, f/2, or in sterilized advanced secondary treated wastewater. Secondly, co-incubation tests estimated MS2 persistence during algal growth. Both infective (plaque assay) and total MS2 (quantitative PCR) were quantified. Little immediate partitioning occurred with most of MS2 recovered in supernatant. Incubation in wastewater or f/2 drastically reduced MS2 viability (

Bacteria may be critical for the functionality, associated productivity, and risk profile of wastewater based algal systems. Both wastewaters and algal stocks act as sources of bacteria effectively creating a tripartite system where it is reasonable to expect interactions between algae, bacteria from wastewater, and algae associated bacteria. The functionality associated with this complex system will be critically derived from the synergistic activities of its biological members, which in turn will be affected by the induced trophic status of the very same system. It is critical that, as algal biofuel research expands into large-scale cultivation trials and production, these interactions and associated functions are assessed, monitored, and considered when management options are being developed.

Understanding how turbulence impacts marine floc formation and breakup is key to predicting particulate carbon transport in the ocean. While floc formation and sinking rate has been studied in the laboratory and in-situ, the breakup response to turbulence has attracted less attention. To address this problem, the breakup response of bentonite clay particles flocculated in salt water was studied experimentally. Flocs were grown in a large aggregation tank under unmixed and mixed aggregation conditions and then subjected to turbulent pipe flow. Particle size was quantified using microscope imaging and in-situ measurements obtained from standard optical oceanographic instruments; a Sequoia Scientific LISST-100X and two WET Labs ac-9 spectrophotometers. The LISST instrument was found to capture the breakup response of flocs to turbulent energy, though the resulting particle size spectra appear to have underestimated the largest floc lengthscales in the flow while overestimating the abundance of primary particles. Floc breakup and the resulting shift towards smaller particles caused an increase in spectral slope of attenuation as measured by the ac-9 instruments. The Kolmogorov lengthscale was not found to have a limiting effect on floc size in these experiments. While the flocs were found to decrease in overall strength over the course of the two-month experimental time period, repeatable breakup responses to turbulence exposure were observed. Hydrodynamic conditions during floc formation were found to have a large influence on floc strength and breakup response. A non-constant strength exponent was observed for flocs formed with more energetic mixing. Increased turbulence from mixing during aggregation was found to increase floc fractal dimension and apparent density, resulting in a shift in the breakup relationships to higher turbulence dissipation rates. The results suggest that marine particle aggregation and vertical carbon transport concepts should include the turbulence energy responsible for aggregate formation and the resulting impact on floc strength, density, and the disruption potential.

Turbulent mixing in the ocean can, in some cases, be so intense as to leave surface imprints, or “boils”, that are detectable from space. Examples include turbulent flow over a submerged obstacle and instability of large-amplitude internal waves. In this paper we examine the particular case of tidal flow over a ~60-m-deep sill, which forms a barrier for the flow of dense water from the Pacific Ocean into the Strait of Georgia. The flow response during flood tide is illustrated using visible and thermal-band satellite and airborne imagery, the latter having high-resolution multi-looks that capture the formative stage of the boils. The image examples capture aspects of the expected flow response based on in situ measurements reported in the literature, but they also suggest differences, and they reveal the level of complexity of the surface structure. A new result is that, after the front is pushed well off the sill, boils emerge several hundred meters downstream from the sill crest, grow at a rate of ~60 m2/s, and attain a size of 3,800 m2 (an equivalent diameter of 70 m) after one minute. These boils appear to arise from vorticity generated by vertical shear at the sill crest, and provide an additional source of vertical mixing and (through wave breaking) air-sea gas exchange.

Airborne hyperspectral and thermal infrared imagery collected over the Florida Current provide a view of the disintegration of a Sargassum drift line in 5 m s −1 winds. The drift line consists mostly of rafts 20–80 m 2 in size, though aggregations larger than 1000 m 2 also occur. Rafts tend to be elongated, curved in the upwind direction, and 0.1–0.5 °C warmer than the surrounding ocean surface. Long weed ‘trails’ extending upwind from the rafts are evidence of plants dropping out and being left behind more rapidly drifting rafts. The raft line may be a remnant of an earlier Sargassum frontal band, which is detectible as an upwind thermal front and areas of submerged weed. Issues are identified that require future field measurements.

Carbon nanotube (CNT) adsorption technology has the potential to support point of use (POU) based treatment approach for removal of bacterial pathogens, natural organic matter (NOM), and cyanobacterial toxins from water systems. Unlike many microporous adsorbents, CNTs possess fibrous shape with high aspect ratio, large accessible external surface area, and well developed mesopores, all contribute to the superior removal capacities of these macromolecular biomolecules and microorganisms. This article provides a comprehensive review on application of CNTs as adsorbent media to concentrate and remove pathogens, NOM, and cyanobacterial (microcystin derivatives) toxins from water systems. The paper also surveys on consideration of CNT based adsorption filters for removal of these contaminants from cost, operational and safety standpoint. Based on the studied literature it appears that POU based CNT technology looks promising, that can possibly avoid difficulties of treating biological contaminants in conventional water treatment plants, and thereby remove the burden of maintaining the biostability of treated water in the distribution systems.

Airborne infrared and synthetic aperture radar imagery collected over the Gulf Stream are used to examine the surface patterns of small-scale thermal convection and wind-driven Langmuir circulation. These patterns have a thermal contrast of ∼0.25 °C, which is roughly an order of magnitude larger than predicted by large-eddy simulations but consistent with the effect on surface temperature of surfactant accumulations induced by mixed-layer eddies.

An adsorption equilibrium and a kinetic study ofBacillus atrophaeuson Single-Wall Carbon Nanotubes (SWCNTs) were here performed to provide the basis for developing biosensor devices for detecting threatening micro-organisms in water supply systems.B. atrophaeusspores and carbon nanotubes were subjected to a batch adsorption process to document their equilibria and kinetics. Here, commercial nanotubes were either studied as received or were acid-purified before adsorption experiments. TheBacillusspores appear to show higher affinity towards the purified nanotubes than to the as-received nanomaterial. The effective diffusivity of the spores onto the purified nanotubes was found to be approximately 30 percent higher than onto the as-received nanotubes. It seems that the removal of amorphous carbon from the as-received nanotubes through a purification process yielded an intimate nantoubes-spore interaction as revealed by transmission electron microscopy. Freundlich model successfully correlated the adsorption equilibrium data for the nanotubes-spore interaction. Transmission electron micrographs showed extensive contact between theBacillusand the purified nanotubes, but the association appeared less intimate between the spores and the as-received nanotubes.

A new analysis methodology based on the wavelet transform is used to estimate the cross-wind scale statistics of high surface temperature events from two-dimensional infrared imagery. The method is applied to laboratory data obtained from an experiment conducted in 2001 at the University of Miami, Rosenstiel School of Marine and Atmospheric Science Air–sea Interaction Saltwater Tank (ASIST). For the case of positive heat flux, in which heat is transported from water to air and for all wind forcing conditions, results from the analysis of infrared images show that the number of high temperature events, when scanned in the cross-wind direction, occupies a wide range of scales. For all wind cases, at a low temperature fluctuation threshold, the number of high temperature events increases with increasing wavenumber (decreasing scale). As the temperature fluctuation threshold is increased, this distribution collapses around a characteristic scale. In addition, as the wind speed increases this scale decreases. The statistical scale results are shown to be consistent with estimates of streak spacing based on a standard parameterization of the turbulent dynamics as well as with the results from numerical experiments. Our results suggest that further statistical analysis may possibly allow for the estimation of wind stress from infrared imagery.

Adsorption equilibrium and kinetics of pure and mixed cultures of Escherichia coli and Staphylococcus aureus on single-walled carbon nanotubes (CNT) aggregates were studied in an effort to develop CNT-based biosensors for quick detection of these bacteria in water. Batch experiments were carried out to measure the adsorption kinetics and equilibrium of pure and mixed culture of E. coli and S. aureus on the CNT aggregates at ambient temperature and various culture concentrations. The CNT aggregates can adsorb significant amounts of E. coli and S. aureus bacteria with different size and shape characteristics. The smaller size S. aureus has a five to ten times faster diffusion rate than E. coli and about 100 times higher adsorption affinity with the carbon nanotube aggregates. Freundlich adsorption model correlates well both the pure component and mixture adsorption equilibrium data. It is quite possible the CNT aggregates have separate adsorption sites for both E. coli and S. aureus. The combined high adsorption affinity and fast adsorption kinetics for S. aureus suggest that even unmodified single-wall carbon nanotubes can selectively differentiate S. aureus and E. coli in water. Transmission electron microscopic analysis qualitatively confirmed the adsorption results and provides direct visualization of the adsorbed bacteria on carbon nanotube aggregates. Both bacteria form biofilms on carbon nanotube aggregates and have a strong tendency to connect with each other rather than with the carbon surface.

Airborne infrared imagery is shown to provide preliminary evidence of surface thermal expressions associated with internal waves that become unstable and break over the continental shelf. These expressions include a narrow wave front that is warmer than the ambient; a wide, spatially intermittent ‘wake’ that is colder than the ambient; and ∼ O (10 m) diameter surface-renewal ‘boils’ that populate the wake. These thermal signatures might be useful in assessing the spatial distribution and structure of breaking internal waves.

The possibility of using single-walled carbon nanotubes (SWCNTs) aggregates as fluorescence sensors for pathogen recognition in drinking water treatment applications has been studied. Batch adsorption study is conducted to adsorb large concentrations ofStaphylococcus aureusaureus SH 1000 andEscherichia colipKV-11 on single-walled carbon nanotubes. Subsequently the immobilized bacteria are detected with confocal microscopy by coating the nanotubes with fluorescence emitting antibodies. The Freundlich adsorption equilibrium constant (k) forS.aureusandE.colidetermined from batch adsorption study was found to be9×108and2×108 ml/g, respectively. The visualization of bacterial cells adsorbed on fluorescently modified carbon nanotubes is also clearly seen. The results indicate that hydrophobic single-walled carbon nanotubes have excellent bacterial adsorption capacity and fluorescent detection capability. This is an important advancement in designing fluorescence biosensors for pathogen recognition in water systems.

Chemotaxonomic information can be extracted from microorganisms through gas chromatographic characterization of pyrolysate which is influenced by pyrolysis time and temperature, gas atmosphere for pyrolysis, and others. The quantitative effects of these parameters were determined using a pyrolysis gas chromatographic instrument equipped with a flame ionization detector. Repeatability of peak heights from the pyrolysis of Micrococcus luteus ranged from 4 to 29% relative standard deviation with an average value of 14% R.S.D. Volatile components with retention times below 5 min increased in peak height 10-fold or more as pyrolysis temperature was increased from 350 to 650 °C and was understood as increased pyrolysis yield. Response was decreased through increases in gas flow through the pyrolysis chamber. The total mass of all volatile compounds formed in pyrolysis of bacteria was 1.1 × 10−6 g while the organic mass from the bacteria was ∼3.9 × 10−4 g. Thus, the conversion of bacterial mass into chromatographic response was 0.28%. Chromatographic profiles of pyrolysates from three bacterial strains were analyzed to find peaks that were distinctive of each bacterial strain and might be tentatively classified as biomarkers.

Quantitative viral risk assessments for wastewaters are notoriously difficult. The often considered quantitative reverse transcriptase PCR reflects poorly on virus infectivity rates leading to inaccurate risk interpretations. Various techniques focused on the degradation of the nucleic acids of non-infective viruses were previously employed. We comparatively assessed the effectiveness of such enzymatic treatments for MS2 bacteriophage in treated wastewaters. The single use of RNase A at an appropriate concentration may be as effective as the combination of RNase followed by Proteinase K and more rapid. While all tested enzymatic treatments minimized recovery of RNA (>95 %) in the absence of infective MS2, none completely eliminated the signal recovery. Selection of any enzymatic protocol for minimizing recovery of RNA from degraded, non-infective viruses should balance the methods efficacy with its expediency.

Programmed cell death, or apoptosis, is an evolutionarily conserved cellular process that controls the destruction of cells during tissue development (34) and immune selection (51), and it is considered to be one of the ancient mechanisms for eliminating cells infected by obligate intracellular pathogens, such as viruses (12). Cellular components of apoptosis machinery include tumor necrosis factor family death receptors that engage soluble or cell-associated ligands to initiate an extrinsic pathway and intracellular stress sensors that initiate an intrinsic pathway of cell death. These share enzymes involved in common steps, including cytosolic protease zymogen caspases that initiate and execute essential steps in the pathway as well as Bcl-2 family proteins that localize to mitochondria and enhance or inhibit apoptosis. Many viruses encode proteins that modulate critical steps in apoptosis, thereby promoting an environment commensurate with viral replication (6). DNA viruses, including adenoviruses, poxviruses, and herpesviruses, express antiapoptotic proteins that imitate cellular functions (12, 19, 22) targeting two major apoptosis checkpoints. One, carried out by FLICE (an acronym for caspase 8) inhibitory proteins, prevents autocatalytic activation of procaspase 8 in the extrinsic pathway of apoptosis that follows activation of death receptors at the plasma membrane. The other, carried out by antiapoptotic Bcl-2 family proteins, blocks mitochondrial membrane permeabilization, a common checkpoint for apoptotic signals originating within or outside the cell. By blocking apoptosis at these points, viruses may prevent cell death occurring as a result of cytokine or cellular immune surveillance as well as the intracellular antiviral response. Human cytomegalovirus (CMV) encodes a range of functions that modulate interaction with host cells (35). This includes two potent cell death suppressors that lack sequence homology with cellular proteins even though they interfere with commonly targeted steps, inhibitor of caspase 8 activation (vICA) and mitochondrial-localized inhibitor of apoptosis (vMIA). Both of these were initially identified through a functional screen of CMV open reading frames in a HeLa cell death suppression assay (23, 48). vICA homologs are broadly distributed in all characterized betaherpesviruses infecting primates as well as rodents (32). Human CMV vICA is dispensable for viral replication in cultured cells (23, 48). vMIA sequence homologs are found only in chimpanzee CMV, rhesus macaque CMV, and African green monkey CMV (32). Murine CMV encodes a newly annotated gene, m38.5, whose position is conserved relative to UL37 homologs in primate CMVs (9, 31). This murine CMV gene product localizes to mitochondria and suppresses apoptosis (31). Although UL37 was initially reported to be critical for viral growth (15, 43, 58), replication is minimally disrupted in human CMV strains that retain a functional copy of vICA (31). The mitochondrial checkpoint of apoptosis that connects external and internal cell death induction signals to downstream nuclear and cytoskeletal events is tightly regulated by the Bcl-2 family of proteins (5). The vMIA family of antiapoptotic proteins (23, 32) functions at a step that appears analogous to Bcl-xL despite the lack of any sequence homology. Human CMV vMIA is a potent suppressor of cell death induced by mitochondrial membrane-permeabilizing agents, reactive oxygen species, and preapoptotic chromatin condensation (3, 7, 55), providing insight into apoptotic signaling and cellular pathways integrating DNA damage with apoptosis checkpoints. Highly conserved regions within vMIA (26) coincide with an amino-terminal mitochondrial targeting domain (amino acids [aa] 1 to 34) and a carboxyl-terminal antiapoptotic domain (AAD) (115 to 147) (32), both of which are contained within a functional 69-aa deletion mutant (Δ35-112/Δ148-163) of the natural protein (26), a derivative that is remarkably similar to some natural primate CMV vMIA homologs (23, 32). The mitochondrial targeting domain is required for activity, which strongly suggests that vMIA-mediated cell death suppression requires proper localization; however, the role of the AAD is not understood. The antiapoptotic Bcl-2 family members Bcl-2 and Bcl-xL bind proapoptotic family members, such as Bax, Bak, and Bid, through a hydrophobic pocket formed by conserved hydrophobic and amphipathic α-helices (36, 40). Viral Bcl-2 homologs are thought to form similar structures and interactions (40). vMIA, though not homologous to Bcl-2 or Bcl-xL, contains a conserved amphipathic α-helical motif within the AAD that we found to be critical in cell death suppression. We identified cellular AAD-dependent binding proteins in order to better characterize the mechanism of cell death suppression and found a common role for GADD45 family members in cell death suppression by vMIA and Bcl-xL. This work suggests that vMIA and Bcl-2 family members share a common cellular partner.

Human cytomegalovirus carries a mitochondria-localized inhibitor of apoptosis (vMIA) that is conserved in primate cytomegaloviruses. We find that inactivating mutations within UL37x1, which encodes vMIA, do not substantially affect replication in TownevarATCC (Towne-BAC), a virus that carries a functional copy of the betaherpesvirus-conserved viral inhibitor of caspase 8 activation, the UL36 gene product. In Towne-BAC infection, vMIA reduces susceptibility of infected cells to intrinsic death induced by proteasome inhibition. vMIA is sufficient to confer resistance to proteasome inhibition when expressed independent of viral infection. Murine cytomegalovirus m38.5, whose position in the viral genome is analogous to UL37x1, exhibits mitochondrial association and functions in much the same manner as vMIA in inhibiting intrinsic cell death. This work suggests a common role for vMIA in rodent and primate cytomegaloviruses, modulating the threshold of virus-infected cells to intrinsic cell death.

Gas phase ions for valine, glutamate, phenylalanine, angiotensin, bradykinin, LH-RH, and bombesin were formed through matrix assisted laser desorption-ionization (MALDI) in air at ambient pressure and were characterized by ion mobility spectrometry (IMS). The IMS drift tube was operated at 100 °C with air as the drift gas and without an ion shutter. Responses were obtained using α-cyano-4-hydroxycinnamic acid as the matrix and a Nd-YAG laser at 355 nm with an unfocused beam at 6 mJ per pulse and 7 mm2 cross section. Matrix and analyte were applied to a borosilicate glass target and microgram amounts of sample provided responses lasting 10 to 15 s with the laser operated at 11 Hz. Detection limits for the peptides were estimated to be 10 to 100 pmol per laser shot. The mobility spectra for individual amino acids and peptides exhibited multiple peaks with spectral distortions and raised baselines. These features and calculated values for reduced mobilities were consistent with the existence of clusters between analyte ions and matrix neutrals and the dissociation of these clusters in the drift region of the analyzer. Mobility spectra with distinctive peaks were not obtained for MALDI-IMS of peptides larger than 5700 amu, though ion formation was suggested from the depletion of matrix signal.

The effect of temperature on the surface tension of soluble and insoluble surfactants was investigated at an air−water interface. Equilibrium surface tension measurements were performed using the Wilhelmy plate technique in which both temperature and concentration were varied systematically. Insoluble surfactants (oleyl alcohol and hemicyanine) and soluble surfactants (Triton X-100 and sodium dodecyl sulfate (SDS)) were used since they are commonly used in hydrodynamic experiments in which the effects of surfactants on free surface dynamics are studied. The principal result of this investigation is that the surface tension of the above-mentioned surfactants decreases linearly with temperature, independent of concentration, with the exception of oleyl alcohol whose surface tension becomes relatively independent of temperature above 23 °C. The adequacy of standard models for surfactant behavior in describing these data is considered.

The human cytomegalovirus major immediate-early (α) protein IE1491aaplays an important role in controlling viral gene expression at low multiplicities of infection. With a transient complementation assay, full-length IE1491aaenhanced the growth ofie1 mutant virus CR208 20-fold better than a deletion mutant lacking 71 carboxyl-terminal amino acids (IE11-420aa). A 16-amino-acid domain between amino acids 476 and 491 was both necessary and sufficient for chromatin-tethering activity; however, this domain was completely dispensable for complementation of CR208 replication. The proximal 55-amino-acid acidic domain (amino acids 421 to 475) was found to be most important for function. A deletion mutant lacking only this domain retained chromatin-tethering activity but failed to complement mutant virus. Interestingly, serine phosphorylation (at amino acids 399, 402, 406, 423, 428, 431, 448, 451, and 455) was not required for complementation. These results show that IE1491aais composed of at least two domains that support replication, a region located between amino acids 1 and 399 that complementsie1 mutant virus replication to low levels and an acidic domain between amino acids 421 and 479 that dramatically enhances complementation.

Airborne infrared imagery collected off the West Florida coast reveals Langmuir circulation patterns having across-wind spacings of the order of ten times the local water depth. This implies a much flatter circulation cell than has been typically reported but supports observations made off the Texas coast by Hunter and Hill (Remote Sensing Environ. 10 (1980) 115). The conditions under which such large-aspect-ratio circulation cells form remain unclear.

The thermal structure of clean and contaminated free-surfaces subject to the transient flow of a gas jet were investigated experimentally. The interface and near-surface flow were examined using optical high-speed (HS) motion analysis, infrared (IR) imagery, and laser-induced fluorescence (LIF). IR imagery revealed an instability in the form of thermal scars on the expanding circular surfactant front. The nature of this instability was explored by performing experiments with both clean and contaminated surfaces. LIF visualization techniques were used to gain insight into the nature of the near-surface flow field. This revealed the presence of a vortex ring that underwent an instability in which ringlets surrounded the primary core. Using simultaneous IR/LIF imaging of a fixed spatial region, it is shown that the thermal scars are spatially and temporally correlated with the near-surface ringlet structures, suggesting that the scars are a surface manifestation of the near-surface structures.

A microfabricated drift tube for differential mobility spectrometry (DMS) was used with pyrolysis-gas chromatography (py-GC) to chemically characterize bacteria through three-dimensional plots of ion intensity, compensation voltage from differential mobility spectra, and chromatographic retention time. The DMS analyzer provided chemical information for positive and negative ions simultaneously from chemical reactions between pyrolysis products in the GC effluent and reactant ions of H+(H2O)n and O2-(H2O)n in air at ambient pressure. Authentic standards for chemicals formed in the pyrolysis of bacteria showed favorable matches with plots from py-GC/DMS analysis and were supported by py-GC/MS results. These and other yet-unidentified constituents provided a means to distinguish Escherichia coli from Micrococcus luteus. A Gram-positive spore former (Bacillus megaterium) was distinguished by an abundant peak for crotonic acid evident in positive and negative ions and not observed with M. luteus. In contrast, plots from py-GC/DMS of lipid A and lipoteichoic acid showed poor matches to plots for a Gram-negative (E. coli) bacterium and a Gram-positive (M. luteus) bacterium and the differences were attributed to differences in genus sources of the biopolymers. A significant percentage of the chemical information available in py-GC/DMS is unidentified, and the analytical utility must be established. Precision in the chemical measurement was determined as +/- 0.2 V, 10% relative standard deviation (RSD), and +/- 0.05 min for compensation voltage, peak intensity, and retention time, respectively. The minimum number of total bacteria (cell forming units) detected was 6000 though detection limits and resolution could be varied by the magnitude of the separation voltage in the differential mobility spectrometer.

Several human channelopathies result from mutations in alpha1A, the pore-forming subunit of P/Q-type Ca2+ channels, conduits of presynaptic Ca2+ entry for evoked neurotransmission. We found that wild-type human alpha1A subunits supported transmission between cultured mouse hippocampal neurons equally well as endogenous mouse alpha1A, whereas introduction of impermeant human alpha1A hampered the effect of endogenous subunits. Thus, presynaptic P/Q-type channels may compete for channel type-preferring "slots" that limit their synaptic effectiveness. The existence of slots generates predictions for how neurotransmission might be affected by changes in Ca2+ channel properties, which we tested by studying alpha1A mutations that are associated with familial hemiplegic migraine type 1 (FHM1). Mutant human P/Q-type channels were impaired in contributing to neurotransmission in precise accord with their deficiency in supporting whole-cell Ca2+ channel activity. Expression of mutant channels in wild-type neurons reduced the synaptic contribution of P/Q-type channels, suggesting that competition for type-preferring slots might support the dominant inheritance of FHM1.

In this study, we investigate the nature of a Reynolds ridge formed by wind shear. We have simultaneously imaged the water surface, with a deposit of a monolayer of the surfactant, oleyl alcohol, subject to different wind shears, by using a high-resolution infrared (IR) detector and a high-speed (HS) digital camera. The results reveal that the regions around the wind-driven Reynolds ridge, which have subtle manifestations in visual imagery, possess surprisingly complex hydrodynamical and thermal structures when observed in the infrared. The IR measurements reveal a warm, clean region upstream of the ridge, which is composed of the so called fishscale structures observed in earlier investigations. The region downstream of the ridge is composed of colder fluid which forms two counter-rotating cells. A region of intermediate temperature, which we call the mixing (wake) region, forms immediately downstream of the ridge near the channel centerline. By measuring the velocity of the advected fishscales, we have determined a surface drift speed of about 2% of the wind speed. The spanwise length-scale of the structures has also been used to estimate the wind shear. In addition, a comparison of IR and visual imagery shows that the thermal field is a very sensitive indicator of the exact position of the ridge itself.

Direct numerical simulations of fully developed turbulence in an open channel were performed. Effects of surfactants on heat transfer and the underlying turbulent structures were investigated. As surface elasticity is increased turbulent fluctuations are damped and the mean surface temperature is decreased. A surface strain model is introduced to explain this behavior in a heuristic manner. A nondimensional parameter representing the ratio of surface elastic forces to local inertial forces is introduced. It is concluded that for values of the parameter of order one, surfactants have strong effects on surface turbulence, whereas an effectively clean surface can be obtained for parameter values less than O(10−3).

The cross-correlation between surface temperature and subsurface velocity is presented for water undergoing evaporative convection. The surface temperature measurements were obtained via quantitative infrared imaging, and the velocity measurements were obtained using a two-component laser Doppler velocimetry (LDV) system. The water surface was covered with a surfactant monolayer, which did not impede evaporation. The largest measured correlation coefficient was 0.375. Correlation coefficients obtained after shifting the velocity and temperature time traces with respect to each other revealed a peak in the correlation coefficient very close to a zero time shift. The significance of these results and their implications for the remote sensing of underwater objects via infrared imaging are discussed.