Outer Sites Research Articles

Amplification and Tuning of Ground Motion at the Outer Cascadia Accretionary Prism

AbstractGround‐motion amplification in the outer Cascadia subduction zone accretionary prism has been documented previously by comparing earthquake and microseismic vertical ground‐motion and pressure records from an ONC/NEPTUNE Canada cabled observatory site on the outer prism to those from a site on the flank of the Juan de Fuca Ridge. Since then, four additional instruments became operational, and data, now spanning 10 years, include more than 100 large (Mw > 7) distant earthquakes. Well‐tuned response at the outer prism sites is observed in both vertical and horizontal components, with peaks in the spectral ratio of vertical velocity relative to nearby ocean crustal and continental bedrock sites (V/Vref) at 9 s, and in the intra‐site horizontal to vertical spectral ratio horizontal‐to‐vertical spectral ratio at 14 s, both with band widths of ±10% to 15% at half amplitude. The vertical response is consistent with ¼ wavelength compressional wave reinforcement, while the horizontal motion tuning most likely reflects the effects of the low velocity prism sediments on surface‐wave propagation. At the periods of maximum relative motion, outer prism surface‐wave vertical and horizontal accelerations are enhanced by factors of up to 15 and 25, respectively. Similar behaviour is seen in microseismic records from these sites, and, to a lesser extent, in earthquake records from temporarily deployed Cascadia Initiative seismometers along the outer Cascadia prism to the south. Such tuning and amplification must be accounted for when assessing the dynamic behavior of the prism and its basal fault at the time of large local earthquakes.

Seagrass Recovery Following Marine Heat Wave Influences Sediment Carbon Stocks

Worldwide, seagrass meadows accumulate significant stocks of organic carbon (C), known as “blue” carbon, which can remain buried for decades to centuries. However, when seagrass meadows are disturbed, these C stocks may be remineralized, leading to significant CO2 emissions. Increasing ocean temperatures, and increasing frequency and severity of heat waves, threaten seagrass meadows and their sediment blue C. To date, no study has directly measured the impact of seagrass declines from high temperatures on sediment C stocks. Here, we use a long-term record of sediment C stocks from a 7-km2, restored eelgrass (Zostera marina) meadow to show that seagrass dieback following a single marine heat wave (MHW) led to significant losses of sediment C. Patterns of sediment C loss and re-accumulation lagged patterns of seagrass recovery. Sediment C losses were concentrated within the central area of the meadow, where sites experienced extreme shoot density declines of 90% during the MHW and net losses of 20% of sediment C over the following 3 years. However, this effect was not uniform; outer meadow sites showed little evidence of shoot declines during the MHW and had net increases of 60% of sediment C over the following 3 years. Overall, sites with higher seagrass recovery maintained 1.7x as much C compared to sites with lower recovery. Our study demonstrates that while seagrass blue C is vulnerable to MHWs, localization of seagrass loss can prevent meadow-wide C losses. Long-term (decadal and beyond) stability of seagrass blue C depends on seagrass resilience to short-term disturbance events.

Unique designed structure of bimetallic cobalt and nickel oxide nanocages with nitrogen doping as bifunctional catalysts

Efficient bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are essential to improve the sluggish reaction kinetics during cathodic electrochemical processes. In this study, we successfully developed an open-structure cobalt and nickel bimetallic nanocage (CNBN) by aggregating reduced hydrogen gas. The hollow structures have a catalytic advantage because the inner and outer sites are simultaneously active during the ORR and OER reactions. Moreover, this work demonstrates that the synergy effect exceeds that of simply adding nitrogen (N) such as “ensemble effect.” Our nanocages improve the ORR and OER reactions by allowing electron transfer between active metal atoms and doped N atoms. We studied the electrocatalytic activity of CNBN for ORR and OER in alkaline and found CNBN’s catalytic effectiveness to be comparable to Pt/C and Ir/C catalysts. This approach can be applied to cathodic catalysts for use in metal-air battery storage devices.

Unravelling the role of interfacial chemistry evolution in the kinetics of zinc insertion into chevrel phase

The insertion kinetics of the multivalent cations into an intercalation host is conventionally understood primarily focused on the ion migration and charge redistribution properties through the bulk solid framework. Here we show that the intercalation kinetics of zinc ions into a Mo6S8 Chevrel phase is critically dependent on the interfacial chemistry evolution associated with changes in the electrolyte pH and the formation of zinc hydroxide sulfate (ZHS) during the early cycles. The sluggish initial insertion process with a hydroxyl surface groups on Mo6S8 causes a concurrent intercalation of zinc ions into the inner and outer ring vacancy sites, leading to the temporary coexistence of three reaction phases. On the contrary, characteristic two-step, two-phase reactions associated with the sequential occupation of each vacancy site are observed after the electrolyte pH change induces ZHS deposit in the interface, which eliminates hydroxyl adsorption layer on the surface, and promotes the intercalation kinetics of zinc ions. This study provides valuable insight into insertion of multivalent cations into Chevrel phase, which often exhibits a cryptic kinetic dormancy during the initial cation intercalation stages.

Computational classification of core and outer fucosylation of N-glycoproteins in human plasma using collision-induced dissociation in mass spectrometry.

Glycoprotein fucosylation, one of the major posttranslational modifications, is known to be highly involved in proteins related to various cancers. Fucosylation occurs in the core and/or outer sites of N-glycopeptides. Elucidation of the fucosylation type of N-glycoproteins is therefore important. However, it has remained a challenge to classify the fucosylation types of N-glycopeptides using collision-induced dissociation (CID) tandem mass (MS/MS) spectra. The relative intensities of the Y1 F, Y2 F, Y3 F, and Y4 F product ions in the CID-MS/MS spectra of the IgG N-glycopeptides were measured for core fucosylation. The Core Fucose Index (CFI) was then calculated by multiplication of the relative intensities with a weight factor from logistic regression to differentiate between the core and none fucosylation. From the relative intensities of the B2 F and B3 SF ions of the MS/MS spectra of the AGP N-glycopeptides for outer fucosylation, the Outer Fucose Index (OFI) was calculated to differentiate between the outer and none fucosylation. In order to classify core and/or outer fucosylation of N-glycoproteins, we defined the fucosylation score (F-score) by a sigmoidal equation using a combination of the CFI and the OFI. For application, we classified the fucosylation types of N-glycoproteins in human plasma with 99.7% accuracy from the F-score. Human plasma samples showed 54.4%, 33.3%, 10.3%, and 1.6% for none, core, outer, and dual fucosylated N-glycopeptides, respectively. Core fucosylation was abundant at mono- and bi-antennary N-glycopeptides. Outer fucosylation was abundant at tri- and tetra-antennary N-glycopeptides. In total, 113 N-glycopeptides of 29 glycoproteins from 3365 glycopeptide spectral matches (GPSMs) were classified for different types of fucosylation. We established an F-score to classify three different fucosylation types: core, outer, and dual types of N-glycopeptides. The fucosylation types of 20 new N-glycopeptides from 11 glycoproteins in human plasma were classified using the F-score. Therefore, the F-score can be useful for the automatic classification of different types of fucosylation in N-glycoproteins of biological fluids including plasma, serum, and urine.

Tetranuclear zigzag Ag4 and Ag2Pt2 complexes supported by rac-Ph2PCH2P(Ph)CH2P(Ph)CH2PPh2 (rac-dpmppm)

Reaction of AgOTf with a tetraphosphine, rac-bis[(diphenylphosphinomethyl) phenylphosphino]methane (rac-dpmppm), afforded [Ag4(rac-dpmppm)2](TfO)4 (3) which consists of zigzag-arrayed tetranuclear silver(I) ions supported by syn-arrangement of two enantiomeric (RR/SS) dpmppm ligands. Complex 3 readily reacted with XylNC (Xyl = 2,6-dimethylphenyl) to give [Ag4(rac-dpmppm)2(XylNC)2](TfO)4 (4), where two terminal isocyanides attach to the outer Ag sites. Complex 3 has been shown a good precursor for Pt-Ag-Ag-Pt mixed metal array as incubation of 3 with trans-[Pt(CCPh)2(PPh3)2] yielded [Ag2Pt2(CCPh)4(rac-dpmppm)2](TfO)2 (5). Two trans-Pt(CCPh)2 units are incorporated into the terminal positions in a site-selective fashion and the Pt-Ag-Ag-Pt tetranuclear core also adopts a zigzag array supported by syn-arrangement of two rac-dpmppm ligands. The d8 and d10 closed-shell mixed metal centers of 5 exhibited an intense photoluminescence at 534 nm, mainly from an unsymmetric triplet state generated by charge transfer transitions from ligand (acetylide π) to metal centers (Ag2 and PtAg s/pσ), 3LMCT, and to ligands (acetylide π* and dpmppm), 3LLCT. The present results provide fundamental and useful information to construct multinuclear closed-shell metal alignments by utilizing polyphosphine ligands.

Intertidal investigations of early Holocene archaeological deposits from the Núláwitxv tribal area, British Columbia, Canada

In 2016, 2017 an intertidal excavation program was conducted at the outer coastal archaeological site EkTb-9 in the Núláwitxv Tribal Area of Haíɫzaqv (Heiltsuk) territory, British Columbia, Canada. Haíɫzaqv oral history marks this area as a place of origin and longstanding ancestral histories (núyṃ́) have been derived from Núláwitxv. The sea level curve for this area shows that the shoreline was between two and 4 m lower than today from 14,000 to 10,500 years ago. Intertidal subsurface testing was conducted at EkTb-9 with the hope of discovering archaeological deposits of this age. This resulted in the collection of a varied assemblage of lithics from secondary deposits, representing the products of ancestral labour for the Haíɫzaqv community. The assemblage consists of simple flake and core tools, bifaces, and flakes and cores that generally resemble other early Holocene lithic assemblages from coastal sites in British Columbia. Minimum radiocarbon ages were obtained by dating barnacles found on artifacts, dating this area of the site to at least 9535 ± 25 B.P. (10,199–9714 cal B.P.), and demonstrating that intertidal lithic scatters can be assigned minimum ages. Critical to our understanding of the intertidal secondary deposits is a detailed knowledge of site formation processes and how these were affected by sea level change, erosion, and beach deposition. The results of this work provide a framework for approaching methodological challenges associated with excavating, dating, and interpreting intertidal archaeological sites.

Abstract 2394: Rad52 residues associated with colonic adenocarcinoma dictate its cooperative assembly on ssDNA during homologous recombination

Abstract DNA repair is essential for maintaining genomic integrity. Homologous recombination (HR) repairs double- stranded DNA breaks (DSBs) and defects lead to the accumulation of mutations, which results in genomic instability and a plethora of breast, ovarian, colonic and skin cancers. HR is initiated when a DSB is recognized and resected by exonucleases to yield single-stranded DNA (ssDNA), which is then coated and protected by replication protein A (RPA). Next, Rad51 recombinases access the ssDNA preoccupied by RPA. The Rad51 filament is then able to undergo strand-invasion and drive the subsequent stages of HR. The four DNA Binding domains in RPA (DBDs A, B, C and D) enable very tight RPA-ssDNA binding. Therefore, exchange of RPA for Rad51 is assisted by a group of proteins called mediators during this pre-synaptic phase of HR. RAD52 is one such pro-recombinogenic mediator and functions to promote RPA-Rad51 exchange. However, the mechanistic details underlying how Rad52 mediates RPA-Rad51 exchange on ssDNA are not fully resolved. Mutations in mediator proteins such as RAD52 and BRCA2 are prevalent in many cancers. For example, the COSMIC database shows there have been 139 sampled cases of mutations of Rad52 in solid tumors. To understand how Rad52 fulfills its mediator functions, it is important to first understand how Rad52 associates with DNA, and how this affects RPA-Rad51 exchange on ssDNA. To this extent, we have systematically characterized the DNA binding properties of Saccharomyces cerevisiae Rad52 and investigated the effects of Rad52 on RPA-DNA binding in different DNA contexts. Our results show that. Rad52 exists as a heptamer and binds to ssDNA with a Kd of 40.2 ± 3.3 nM which is similar to RPA binding to ssDNA with a Kd of 29.2 ± 4 nM. Using Protein Induced Fluorescent Enhancement (PIFE), we show that Rad52 binds cooperatively towards the 5′ end of DNA. This cooperativity arises from DNA binding to two distinct sites in Rad52: outer- and inner-binding site. In humans, mutations in the amino acids located in the inner binding site has been found in adenocarcinoma. We have perturbed and characterized a specific inner site mutation, R37A, that is associated with multiple cases of colonic adenocarcinoma, as well as other amino acids in the inner and outer binding sites. This has allowed us to develop a model of dynamic ssDNA-Rad52 binding. Finally, we show that this cooperativity in Rad52 selectively affects the DNA binding of RPA-DBD-D on a 5′ overhang DNA substrate. A detailed mechanistic insight into Rad52-ssDNA binding will aid in a better understanding of HR, which can contribute to the development of small-molecule inhibitor drugs that can be used as effective chemotherapeutic agents against cancers in the future. Citation Format: Emma A. Tillison, Nilisha Pokhrel, Jaigeeth Deveryshetty, Edwin Antony. Rad52 residues associated with colonic adenocarcinoma dictate its cooperative assembly on ssDNA during homologous recombination [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2394.

Convex polyominoes revisited: enumeration of outer site perimeter, interior vertices, and boundary vertices of certain degrees

The main contribution of this paper is a new column-by-column method for the decomposition of generating functions of convex polyominoes suitable for enumeration with respect to various statistics including but not limited to interior vertices, boundary vertices of certain degrees, and outer site perimeter. Using this decomposition, among other things, we show that (A) the average number of interior vertices over all convex polyominoes of perimeter is asymptotic to (B) the average number of boundary vertices with degree two over all convex polyominoes of perimeter is asymptotic to Additionally, we obtain an explicit generating function counting the number of convex polyominoes with n boundary vertices of degrees at most three and show that this number is asymptotic to Moreover, we show that the expected number of the boundary vertices of degree four over all convex polyominoes with n vertices of degrees at most three is asymptotically (C) the number of convex polyominoes with the outer-site perimeter n is asymptotic to and show the expected number of the outer-site perimeter over all convex polyominoes with perimeter is asymptotic to Lastly, we prove that the expected perimeter over all convex polyominoes with the outer-site perimeter n is asymptotic to .

Quantum excitation transfer, entanglement, and coherence in a trimer of two-level systems at finite temperature

The excitation probabilities, concurrence, and relative entropy of coherence for an array of three coupled two-level systems are studied analytically and numerically at various temperatures. We determine the excitation probabilities for each site, the concurrence between the outer sites, and the relative entropy of coherence of the system for three energy configurations of the trimer and various temperatures. We find that a well configuration (i.e., negative detuning of the inner site) at all temperatures localizes the excitation on the inner site, while a barrier configuration (i.e., positive detuning of the inner site) causes the excitation to be localized on the outer sites. We determine the decay times for the probabilities, concurrence, and relative entropy of coherence for all energy configurations at each temperature. The barrier configuration creates the largest concurrence at zero temperature; however, we find that the uniform configuration is able to resist the loss of quantum coherence and entanglement at higher temperatures more so than any of the other configurations.

Biochemical and structural characterization of a thermostable Dps protein with His-type ferroxidase centers and outer metal-binding sites.

The DNA‐binding protein from starved cells (Dps) is found in a wide range of microorganisms, and it has been well characterized. However, little is known about Dps proteins from nonheterocystous filamentous cyanobacteria. In this study, a Dps protein from the thermophilic nonheterocystous filamentous cyanobacterium Thermoleptolyngbya sp. O‐77 (TlDps1) was purified and characterized. PAGE and CD analyses of TlDps1 demonstrated that it had higher thermostability than previously reported Dps proteins. X‐ray crystallographic analysis revealed that TlDps1 possessed His‐type ferroxidase centers within the cavity and unique metal‐binding sites located on the surface of the protein, which presumably contributed to its exceedingly high thermostability.

Environmental Distribution of Styrene Oligomers (SOs) Coupled with Their Source Characteristics: Tracing the Origin of SOs in the Environment

Despite growing concerns regarding plastic additives, their environmental fate coupled with leaching from source materials are not well known. Styrene oligomers (SOs), which are unintended additives in expanded polystyrene (EPS), are estrogenic micropollutants. Here, we identified the effects of their potential sources (i.e., EPS buoy and its leachate) and environmental dilution on SO distribution within coastal sediments. SO content in fresh EPS particles was 0.1% (w/w), dominated by 2,4,6-triphenyl-hexene (ST-1), while 2,4-diphenyl-1-butene (SD-2) accounted for most of the SOs in EPS leachate, indicating its faster leachability. In lake and offshore environments, the SO composition profiles from their terrestrial inputs and inner sites were similar to those of EPS leachate; meanwhile, the exponentially decreasing SO concentration and increasing styrene trimers (STs) fraction with distance from the inner to outer sites were evident. These profiles indicated continuous SO leaching from their potential sources in the inland, followed by a change in SOs due to environmental dilution. SOs in beach sediment implied the presence of micro-sized EPS particles. We suggest the ST-1 to SD-2 ratio as an index to differentiate among freshly leached SOs (∼0.02), environmentally diluted SOs after leaching (∼0.1), SOs in fresh EPS (∼1.2), and SOs in aged EPS (> 2).

Photophysics and visible light photodissociation of supramolecular meso-tetra(4-pyridyl) porphyrin/RuCl2(CO)(PPh3)2 structures.

In the last decades, supramolecular structures have been explored in many technological efforts. One example of such supramolecules is attained when ruthenium complexes are attached in the outer sites of a porphyrin. Ruthenium complexes act as modulators of the photophysical processes of macrocyclic molecules. Besides the investigation of the main changes introduced by the ruthenium complexes in the electronic and vibronic properties, and in the excited state deactivation processes of porphyrins, discussions concerning the photostability of these supramolecules are much needed. Here, we investigate the supramolecular free-base meso-tetra(4-pyridyl) porphyrin decorated with "RuCl2(CO)(PPh3)2" ruthenium species linked at each of its (4-pyridyl) moieties. The modifications in the photophysical processes introduced by the metallic outlying species are discussed and our results suggest an energy transfer process from the porphyrin B-band to the ruthenium complex MLCT-band. The demonstration of visible light photodissociation of the supramolecule, via both pulsed and continuous laser, is also addressed.

Geometrical and electronic properties of unstrained and strained transition metal dichalcogenide nanotubes

We study geometries and electronic properties of unstrained and strained zigzag $\mathrm{Mo}X{}_{2}$ ($X$ = O, S, and Se) nanotubes and $\mathrm{Mo}XY$ ($X,Y$ = O, S, and Se) nanotubes in the framework of density functional theory. Using the local density approximation, we obtain fully relaxed geometries of (10,0) and (14,0) nanotubes for all $\mathrm{Mo}X{}_{2}$, and (7,0) and (28,0) nanotubes for selected $\mathrm{Mo}X{}_{2}$. From the detailed analysis of the optimized geometries it is revealed that, although in the planar case these transition metal dichalcogenides (TMDs) normally take so-called H structures, zigzag nanotubes turn into geometries between H-like and T-like nanotubes having different height for inner and outer chalcogen site. Electronic property investigations reveal that TMD nanotubes without oxygen atoms are found to have narrower gaps than TMD nanotubes with oxygen atoms. These narrow direct gaps of TMD nanotubes should be attractive properties for infrared optoelectronic devices. On the other hand, energy-gap values of the TMD nanotubes with oxygen atoms are found to depend rather strongly on the strain. Therefore, they should be potential future device materials for mechanical sensors. We also find a global strong correlation between the fundamental-gap values and some combined structural parameters in strained $\mathrm{Mo}X{}_{2}$ ($X$ = S, Se) nanotubes and planar $\mathrm{Mo}X{}_{2}$ ($X$ = S, Se), which will be useful to predict gap values of other strained and unstrained ($n,0$) nanotubes.

Heterogeneous mechanical hyperelastic behavior in the porcine annulus fibrosus explained by fiber orientation: An experimental and numerical approach

Our aim is to estimate regional mechanical properties of the annulus fibrosus (AF) using a multi-relaxation tensile test and to examine the relevance of using the transverse dilatations in the identification procedure. We collected twenty traction specimens from both outer (n = 10) and inner (n = 10) sites of the anterior quadrant of the annulus fibrosus of one pig spine. A 1-h multi-relaxation tensile test in the circumferential direction allowed us to measure the force in the direction of traction and the dilatations in all three directions. We performed a specific-sample finite element inverse analysis to identify variations, along the radial position, of material and structural parameters of a hyperelastic compressible and anisotropic constitutive law. Our experimental results reveal that the outer sites are subjected to a significantly greater stress than the inner sites and that both sites exhibit an auxetic behavior. Our numerical results suggest that the inhomogeneous behavior arises from significant variations of the fiber angle taken into account within the hyperelastic constitutive law. In addition, we found that the use of the measured transverse dilatations in the identification procedure had a strong impact on the identified mechanical parameters. This pilot study suggests that, in quasi-static conditions, the annulus fibrosus may be modeled by a hyperelastic compressible and anisotropic law with a fiber angle gradient from inner to outer periphery.

Effects of copper and temperature on heart mitochondrial hydrogen peroxide production

High energy demand for continuous mechanical work and large number of mitochondria predispose the heart to excessive reactive oxygen species (ROS) production that may precipitate oxidative stress and heart failure. While mitochondria have been proposed as a unifying cellular target and driver of adverse effects induced by diverse stressful states, there is limited understanding of how heart mitochondrial ROS homeostasis is affected by combinations of stress factors. Thus, we probed the effect of copper (Cu) and thermal stress on ROS (as hydrogen peroxide, H2O2) emission and elucidated the effects of Cu on ROS production sites in rainbow trout heart mitochondria using the Amplex UltraRed-horseradish peroxidase detection system optimized for our model. Mitochondria oxidizing malate-glutamate or succinate were incubated at 4, 11 (control) and 23 °C and exposed to a range (1–100 μM) of Cu concentrations. We found that the rates and patterns of H2O2 emission depended on substrate type, Cu concentration and temperature. In mitochondria oxidizing malate-glutamate, Cu increased the rate of H2O2 emission with a spike at 1 μM while temperature had no effect. In contrast, both temperature and Cu increased the rate of H2O2 emission in mitochondria oxidizing succinate with a prominent spike at 25 μM Cu. The rates of H2O2 emission at the three temperatures during the spike imposed by 25 μM Cu were of the order 11 > 23 > 4 °C. Interestingly, 5 μM Cu supressed H2O2 emission in mitochondria oxidizing succinate or malate-glutamate suggesting a common mechanism of action independent of substrate type. In the absence of Cu, the site-specific capacities of H2O2 emission were: complex III outer ubiquinone binding site (site IIIQo) > complex II flavin site (site IIF) ≥ complex I flavin site (site IF) > complex I ubiquinone-binding site (site IQ). Rotenone marginally increased succinate-driven H2O2 emission suggesting either the absence of reverse electron transport (RET)-driven ROS production at site IQ or masking of the expected rotenone response (reduction) by H2O2 produced from other sites. Cu acted at multiple sites in the electron transport system resulting in different site-specific H2O2 emission responses depending on the concentration. Specifically, site IF H2O2 emission was suppressed by Cu concentration-dependently while H2O2 emission by site IIF was inhibited and stimulated by low and high concentrations of Cu, respectively. Additionally, emission from site IIIQo was stimulated by low and inhibited by high Cu concentrations. Overall, our study unveiled distinctive effects and sites of modulation of mitochondrial ROS production by Cu with implications for cardiac redox signaling networks and development of mitochondria-targeted Cu-based drugs.

Differential remodeling of the electron transport chain is required to support TLR3 and TLR4 signaling and cytokine production in macrophages

Increasing evidence suggests that mitochondria play a critical role in driving innate immune responses against bacteria and viruses. However, it is unclear if differential reprogramming of mitochondrial function contributes to the fine tuning of pathogen specific immune responses. Here, we found that TLR3 and TLR4 engagement on murine bone marrow derived macrophages was associated with differential remodeling of electron transport chain complex expression. This remodeling was associated with differential accumulation of mitochondrial and cytosolic ROS, which were required to support ligand specific inflammatory and antiviral cytokine production. We also found that the magnitude of TLR3, but not TLR4, responses were modulated by glucose availability. Under conditions of low glucose, TLR3 engagement was associated with increased ETC complex III expression, increased mitochondrial and cytosolic ROS and increased inflammatory and antiviral cytokine production. This amplification was selectively reversed by targeting superoxide production from the outer Q-binding site of the ETC complex III. These results suggest that ligand specific modulation of the ETC may act as a rheostat that fine tunes innate immune responses via mitochondrial ROS production. Modulation of these processes may represent a novel mechanism to modulate the nature as well as the magnitude of antiviral vs. inflammatory immune responses.

Potential mobility assessment of metals in salt marsh sediments from San Antonio Bay

The BCR method was applied on sediments from the salt marsh of San Antonio Bay (SAB). It presents several channels among which the Encerrado is the most important and is impacted by abandoned mining wastes. The pseudototal concentrations of metals measured within this channel were relatively higher than in outer sites, and according to the Igeo index, its contamination level was low. The metal distribution in the different phases of sediment particles showed that the residual component, considered the safest from the environmental point of view, accounted for most of the Fe, Cd, Cu, and Zn contents. Conversely, Pb was mainly in the non-residual component as part of the reducible fraction, thus constituting the main environmental hazard among the studied elements. The predominance of residual and reducible fractions indicated a historic contamination of metal such as Pb, Cu, and Zn from the mining wastes. The low exchangeable and oxidizable fractions would indicate no actual input of metals.

Rapid subsidence and preservation of fluvial signals in an otherwise wave-reworked delta front succession: Early-mid Pliocene Orinoco continental-margin growth, SE Trinidad

Outcrops of the early-mid Pliocene Orinoco Delta succession on the Atlantic-facing Trinidad continental margin demonstrate facies and stratigraphic architecture of a shelf margin developed in a setting of high sediment supply (Orinoco River) and unusually rapid, sediment accumulation/subsidence (averaging >1 km/My). The studied Moruga clastic wedge of the Orinoco margin consists of a series of topset to deepwater clinoforms with channelized sandstones, river- and mixed-process delta front, wave-dominated delta front, shoreface, prodelta-offshore transition-shelf, upper-slope turbidite channels and mass-transport deposits. The succession is sand-prone and generally consists of coarsening- and thickening-upward delta-front lobes with hummocky/swaley and wave-ripple stratified sandstones indicating dominant storm wave reworking of the delta, particularly when the delta lobes had reached outer shelf sites after long shelf transits. The lower parts of distributary channels are well preserved and characterized by cross-bedded to parallel-laminated sandstones with mud clast lags. The upper parts of channel fills were wave reworked during transgressions, creating hummocky/swaley cross-stratified strata. River-dominated and mixed-process (wave and tide) delta-front deposits occur commonly within stacked, coarsening-upward units. The river-dominated delta front deposits exhibit parallel-laminated to current ripple-laminated intervals with normally graded thin beds changing upward to parallel and low-angle cross lamination, but mixed-process delta front deposits also contain wave and bidirectional current ripples as well as discrete intervals of hummocky/swaley cross-stratification. The preservation of the channel-base as well as river- and mixed-process delta-front deposits in the otherwise storm wave-dominated Atlantic-facing setting suggests some sheltering of the coastal morphology, and possibly low-frequency of large storms, but it is more likely that the unusually rapid subsidence (at rates competing well with Icehouse rates of eustatic sea-level change) and burial of deposits may have prevented the fluvial and tidal signals from being completely reworked by the storm waves in the studied outcrop area. This study demonstrates an example of how the interactions of river-, tide- and wave-generated facies impacted stratigraphic architecture of a rapid subsiding shelf margin built by shelf-edge deltas with high sediment supply.

Numerical study of amplitude modulation in the atmospheric boundary layer at very high Reynolds number

Wall model large eddy simulations (WMLES) are carried out to investigate the amplitude modulation exerted on near-wall small-scale motions by outer layer large-scale motions in the atmospheric boundary layer at high Reynolds number O(106–107). The properties of the mean and fluctuating velocities show good agreement with those found in previous studies. Furthermore, the positions at which there is no amplitude modulation found in the present study are consistent with those found in previous studies. A new phenomenon is observed, namely, that the value of the negative maximum correlation at high Reynolds number is smaller than that at low and moderate Reynolds number. Further investigation shows that the negative maximum correlation decreases with increasing Reynolds number, which could be explained by intermittency effects. There is good agreement of the correlation for different values of the Reynolds number when scaled with outer variables, which confirms that the large boundary-layer-height-scaled events that inhabit the logarithmic region are the source of amplitude modulation. This is confirmed by the locations of other characteristic points, which are independent of Reynolds number. In contrast, when scaled with inner variables, these characteristic points have a strong linear dependence on Reynolds number. Furthermore, the reversal in sign of the correlation corresponds to the crossover points of small-scale turbulent intensity and the local peak in the energy distribution, which gives the first and secondary crossover points a specific physical meaning. Finally, we provide an overview of the energy distribution, which gives an intuitive view of the outer peak energy site.