Site Of Deposition Research Articles

Interface ion-exchange strategy of MXene@FeIn2S4 hetero-structure for super sodium ion half/full batteries

Herein, a well-designed hierarchical architecture of bimetallic transition sulfide FeIn2S4 nanoparticles anchoring on the Ti3C2 MXene flakes has been prepared by cation exchange and subsequent high-temperature sulfidation processes. The introduction of MXene substrate with excellent conductivity not only accelerates the migration rate of Na+ to achieve fast reaction dynamics but provides abundant deposition sites for the FeIn2S4 nanoparticles. In addition, this hierarchical structure of MXene@FeIn2S4 can effectively restrain the accumulation of MXene to guarantee the maximized exposure of redox active sites into the electrolyte, and simultaneously relieve the volume expansion in the repeated discharging/charging processes. The MXene@FeIn2S4 displays outstanding rate capability (448.2 mAh g−1 at 5 A g−1) and stable long cycling performance (428.1 mAh g−1 at 2 A g−1 after 200 cycles). Moreover, the Nay-In6S7 phase detected by ex-situ XRD and XPS characterization may be regarded as a “buffer” to maintain the stability of the Fe-based components and enhance the reversibility of the electrochemical reaction. This work confirms the practicability of constructing the hierarchical structure bimetallic sulfides with the promising electrochemical performance.

Loss of PML nuclear bodies in familial amyotrophic lateral sclerosis-frontotemporal dementia

Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) are two neurodegenerative disorders that share genetic causes and pathogenic mechanisms. The critical genetic players of ALS and FTD are the TARDBP, FUS and C9orf72 genes, whose protein products, TDP-43, FUS and the C9orf72-dipeptide repeat proteins, accumulate in form of cytoplasmic inclusions. The majority of the studies focus on the understanding of how cells control TDP-43 and FUS aggregation in the cytoplasm, overlooking how dysfunctions occurring at the nuclear level may influence the maintenance of protein solubility outside of the nucleus. However, protein quality control (PQC) systems that maintain protein homeostasis comprise a cytoplasmic and a nuclear arm that are interconnected and share key players. It is thus conceivable that impairment of the nuclear arm of the PQC may have a negative impact on the cytoplasmic arm of the PQC, contributing to the formation of the cytoplasmic pathological inclusions. Here we focused on two stress-inducible condensates that act as transient deposition sites for misfolding-prone proteins: Promyelocytic leukemia protein (PML) nuclear bodies (PML-NBs) and cytoplasmic stress granules (SGs). Upon stress, PML-NBs compartmentalize misfolded proteins, including defective ribosomal products (DRiPs), and recruit chaperones and proteasomes to promote their nuclear clearance. SGs transiently sequester aggregation-prone RNA-binding proteins linked to ALS-FTD and mRNAs to attenuate their translation. We report that PML assembly is impaired in the human brain and spinal cord of familial C9orf72 and FUS ALS-FTD cases. We also show that defective PML-NB assembly impairs the compartmentalization of DRiPs in the nucleus, leading to their accumulation inside cytoplasmic SGs, negatively influencing SG dynamics. Although it is currently unclear what causes the decrease of PML-NBs in ALS-FTD, our data highlight the existence of a cross-talk between the cytoplasmic and nuclear PQC systems, whose alteration can contribute to SG accumulation and cytoplasmic protein aggregation in ALS-FTD.

Multi-layer metallogeny of the maoping carbonate-hosted Pb–Zn deposit, SW China: Constraints from C–O–S–Pb isotopes

The Maoping carbonate-hosted Pb–Zn deposit, located in the Sichuan-Yunnan-Guizhou metallogenic belt (SYGMB), comprises numerous ore bodies hosted in Devonian and Carboniferous Systems. Multi-layer Pb–Zn mineralization (two or more systems) at deposit scale is still rare in the SYGMB and poorly understood. Although δ18O values (+9.4 to +12.3‰) of calcite in Devonian System is similar to those (+9.2 to +12.0‰) of calcite in Carboniferous System, δ13C values (−1.7 to −0.2‰) of calcite in Devonian System is significantly higher than those (−5.4 to −2.7‰) of calcite in Carboniferous System. Such C–O isotopic characteristics suggest that the source of C was ore-hosting carbonate rocks, whereas the source of O was basement metamorphic rocks. The simulation of C–O isotopes shows that water-rock interaction was the main mechanism for calcite precipitation. The δ34S values (+18.3 to +22.7‰) of sulfides in Devonian System are higher than those (+7.1 to +17.5‰) of sulfides in Devonian System. This implies that reduced sulfur in Devonian System originated from Devonian marine sulfate, while those in Carboniferous System originated from Carboniferous marine sulfate. Such S isotopic compositions also show that thermochemical sulfate reduction (TSR) was the dominant mechanism for the reduction of marine sulfate. The isotopic ratios (206Pb/204Pb = 18.680–18.744, 207Pb/204Pb = 15.753–15.764, 208Pb/204Pb = 39.282–39.399) of galena in Devonian System and those (206Pb/204Pb = 18.554–18.581, 207Pb/204Pb = 15.722–15.752, 208Pb/204Pb = 39.018–39.109) of galena in Carboniferous System are similar to those of basement metamorphic rocks and cover carbonate rocks. This indicates that ore-forming metals had mixed sources. Considering the above results, the multi-layer metallogeny is the mixing of metal and sulfate-bearing fluids with metal-rich but reduced sulfur-poor fluids at the depositional site where methane or other organic matter reduces sulfate and precipitates sulfides. In the future, A multi-layer exploration strategy for Pb–Zn deposits in the SYGMB should be emphasized.

Dissipative Seismicity for Hydrocarbon Reservoir Parameter Evaluation

The natural seismic background of the Earth and its deep emission component are a form of dissipation of energy of geodynamic processes. The methods of studying the seismic background as a signal generated by an open complex non-linear system (the Earth’s crust) can be grouped under one branch—dissipative seismicity. In this paper, one of such methods, namely, the thermodynamic indicator of the state of rocks, is used for the remote evaluation of the local productivity of the reservoir on the hydrocarbon deposit site. The thermodynamic indicator was created using the Klimontovich entropy and yields quantitative estimates of the local disequilibrium of rocks associated with the activity of geophysical processes. We revealed monotonic, near-linear relationship between the thermodynamic indicator values calculated using the seismic background records and the cumulative thickness of productive layers in the wells in close proximity to recording points. The thermodynamic indicator is calculated assuming that there is a sliding time window threshold that must be taken empirically. The obtained results show that the thermodynamic indicator can be effectively used for outlining the deposit boundaries and choosing the potentially most productive well drilling points by extrema in the indicator value field.

Isolation and identification of microorganisms from bitumen, and soil around bitumen deposit site

Isolation of microorganisms from hydrocarbon and oil polluted environment has been reported over the years. This study focused on the isolation and identification of microorganisms from bitumen, and soil around bitumen deposit site. Microorganisms were isolated from soil sample collected around bitumen deposit and bitumen itself using pour plate method. The cultural and morphological characteristics of each bacteria isolates such as colony shape, elevation, pigmentation, colour, cell shape, gram reaction, motility, and endospore test were carried out. From the result, the following bacteria were identified; Acinetobacter sp (soil and bitumen), Pseudomonas Aeruginosa (soil), Bacillus subtilis (soil and bitumen), Staphylococcus aureus (soil). Mould isolation was carried out by cutting a small portion of mycelium, stained it with cotton blue in lactophenol and the examined carefully under light microscope with x40 0bjective. The result revealed the following mould isolates; Aspergillus niger and Arthrobotrys oligospora both isolated from the soil. The result showed the isolation of microorganisms from bitumen and soil around bitumen deposit, thus their potential usefulness in remediation of bitumen polluted environment if the exploitation of the resource commenced.

Directional Reconstruction of Iron Oxides to Active Sites for Superior Water Oxidation

AbstractRationally constructing and manipulating the in situ formed catalytically active surface of catalysts remains a tremendous challenge for a highly efficient water electrolysis. Herein, an anion and cation co‐induced strategy is presented to modulate in situ catalyst dissolution‐redeposition and to achieve the directional reconstruction of Zn and S co‐doped Fe2O3 and Fe3O4 on iron foams (Zn,S‐Fe2O3‐Fe3O4/IF), for oxygen evolution reaction (OER). Benefiting from Zn, S co‐doping and the presence of Fe3O4, a directionally reconstructed surface is obtained. The Fe2O3 in the Zn,S‐Fe2O3‐Fe3O4/IF is directionally reconstructed into FeOOH (Zn,S‐Fe3O4‐FeOOH/IF), in which the S leaching promotes the Fe dissolution and the Zn co‐deposition regulates the activity of the obtained FeOOH. Moreover, the presence of Fe3O4 provides a stable site for FeOOH deposition, and thus causes more FeOOH active components to be formed. Directionally reconstructed Zn,S‐Fe3O4‐FeOOH/IF outperformes many state‐of‐the‐art OER catalysts and demonstrates a remarkable stability. The experimental and density functional theory (DFT) calculation results show that the introduction of Zn‐doped FeOOH with abundant oxygen vacancies through directional reconstruction has activated lattice O atoms, facilitating the OER process on the heterojunction surface following the lattice oxygen mechanism (LOM) pathway. This work makes a stride in co‐induced strategy modulating directional reconstruction.

” Where water wells up”

The article presents a deposition of ornaments from the Late Nordic Bronze Age period V. An archaeological excavation along with non-pollen Palynomorph (NPP) and pollen ana-lysis has resulted in new knowledge about the poorly illuminated Bronze Age tradition of spring offerings. With a starting point in the find at Hedegyden this article aims to improve the understanding of the Bronze Age depositional practices in relation to springs. The article presents the ornaments, but focuses on their context as regards to the relationship between the objects within the deposition, as well as the site of deposition. Based on the strati-graphic observations, the preserved organic materials in the Hedegyden find and the scientific analyses, a chaîne opératoire is presented for the various sub-elements and phases of the depositional act.

Passive Sampling-Based versus Conventional-Based Metrics for Evaluating Remediation Efficacy at Contaminated Sediment Sites: A Review.

Passive sampling devices (PSDs) are increasingly used at contaminated sites to improve the characterization of contaminant transport and assessment of ecological and human health risk at sediment sites and to evaluate the effectiveness of remedial actions. The use of PSDs after full-scale remediation remains limited, however, in favor of evaluation based on conventional metrics, such as bulk sediment concentrations or bioaccumulation. This review has three overall aims: (1) identify sites where PSDs have been used to support cleanup efforts, (2) assess how PSD-derived remedial end points compare to conventional metrics, and (3) perform broad semiquantitative and selective quantitative concurrence analyses to evaluate the magnitude of agreement between metrics. Contaminated sediment remedies evaluated included capping, in situ amendment, dredging and monitored natural recovery (MNR). We identify and discuss 102 sites globally where PSDs were used to determine remedial efficacy resulting in over 130 peer-reviewed scientific publications and numerous technical reports and conference proceedings. The most common conventional metrics assessed alongside PSDs in the peer-reviewed literature were bioaccumulation (39%), bulk sediments (40%), toxicity (14%), porewater grab samples (16%), and water column grab samples (16%), while about 25% of studies used PSDs as the sole metric. In a semiquantitative concurrence analysis, the PSD-based metrics agreed with conventional metrics in about 68% of remedy assessments. A more quantitative analysis of reductions in bioaccumulation after remediation (i.e., remediation was successful) showed that decreases in uptake into PSDs agreed with decreases in bioaccumulation (within a factor of 2) 61% of the time. Given the relatively good agreement between conventional and PSD-based metrics, we propose several practices and areas for further study to enhance the utilization of PSDs throughout the remediation of contaminated sediment sites.

P-541 Does the IVF embryo remain at the site of deposition in successful IVF cycles?

Abstract Study question Does the placement of the IVF embryo differ from the implantation site? Summary answer At five weeks the implanted embryo has not moved in the lateral plane of the endometrial cavity but is slightly lower in the vertical plane. What is known already We previously showed that vertical placement of embryos approximately 9 mm from the fundus and equidistant from the tubal ostia has the highest implantation rate. Whether the embryo migrates from the point where the droplet is deposited before implantation is controversial. We used 3D ultrasound to compare the point of placement with the location of the gestational sac (GS) at 5 weeks gestational age (GA). Study design, size, duration Prospective analysis of 292 transfers of single egg donation blastocysts (2018-2020) and 139 resultant pregnancies in which the position of the GS in the coronal plane at 5 weeks was compared to that of the embryo flash immediately post transfer. A Voluson 6 with a 4D RAB4-8 transabdominal probe imaged the embryo transfer and a 4D RIC-5-9 transvaginal probe imaged the pregnancy scan (GE Healthcare, Austria). Participants/materials, setting, methods Consecutive patients with a normal uterine cavity undergoing egg donation in a single private IVF Center. Embryo transfers were performed under 2D US guidance using a soft Wallace Catheter. A 3D volume of the uterus was acquired immediately post-transfer. A second 3D scan was performed at 5 weeks GA. Distances of the embryo flash and the center of GS from the fundus, ostia and internal cervical os (ICO) were recorded and compared using SPSS. Main results and the role of chance Of 292 transfer procedures, 139 pregnancies who had the first ultrasound in our Center were included and analysed. The mean distance between the embryo flash and the uterine fundus was significantly less than the distance between the center of the GS and the uterine fundus [(9,49±3,03 vs 11,02±3,9 mm respectively (p < 0,05)]. The mean distances between the embryo flash and the right and left ostium were 16,66 ± 4,96 and 16,69 ± 4,61 mm respectively, with no significant differences from the same distances taken from the center of the GS. Limitations, reasons for caution As the image is of the embryo flash and not the embryo, this might have been misleading. Wider implications of the findings These findings extend and support the proposal of an optimal point of embryo placement for pregnancy. The apparent vertical difference in the implantation of the embryo could be due to uterine growth or it could be consequence of uterine peristalsis. This bears further study. Trial registration number not applicable

Oral toxicological study of titanium dioxide nanoparticles with a crystallite diameter of 6 nm in rats

BackgroundThough titanium dioxide (TiO2) is generally considered to have a low impact in the human body, the safety of TiO2 containing nanosized particles (NPs) has attracted attention. We found that the toxicity of silver NPs markedly varied depending on their particle size, as silver NPs with a diameter of 10 nm exhibited fatal toxicity in female BALB/c mice, unlike those with diameters of 60 and 100 nm. Therefore, the toxicological effects of the smallest available TiO2 NPs with a crystallite size of 6 nm were examined in male and female F344/DuCrlCrlj rats by repeated oral administration of 10, 100, and 1000 mg/kg bw/day (5/sex/group) for 28 days and of 100, 300, and 1000 mg/kg bw/day (10/sex/group) for 90 days.ResultsIn both 28- and 90-day studies, no mortality was observed in any group, and no treatment-related adverse effects were observed in body weight, urinalysis, hematology, serum biochemistry, or organ weight. Histopathological examination revealed TiO2 particles as depositions of yellowish-brown material. The particles observed in the gastrointestinal lumen were also found in the nasal cavity, epithelium, and stromal tissue in the 28-day study. In addition, they were observed in Peyer's patches in the ileum, cervical lymph nodes, mediastinal lymph nodes, bronchus-associated lymphoid tissue, and trachea in the 90-day study. Notably, no adverse biological responses, such as inflammation or tissue injury, were observed around the deposits. Titanium concentration analysis in the liver, kidneys, and spleen revealed that TiO2 NPs were barely absorbed and accumulated in these tissues. Immunohistochemical analysis of colonic crypts showed no extension of the proliferative cell zone or preneoplastic cytoplasmic/nuclear translocation of β-catenin either in the male or female 1000 mg/kg bw/day group. Regarding genotoxicity, no significant increase in micronucleated or γ-H2AX positive hepatocytes was observed. Additionally, the induction of γ-H2AX was not observed at the deposition sites of yellowish-brown materials.ConclusionsNo effects were observed after repeated oral administration of TiO2 with a crystallite size of 6 nm at up to 1000 mg/kg bw/day regarding general toxicity, accumulation of titanium in the liver, kidneys, and spleen, abnormality of colonic crypts, and induction of DNA strand breaks and chromosomal aberrations.

Designing Aerosol Therapies Based on the Integrated Evaluation of In Vitro, In Vivo, and In Silico Data.

Despite the advantages of the pulmonary route of administration and inhalable dosage forms, other routes of administration and dosage forms are often considered first to treat lung diseases. This occurs, in part, due to the perceived limitations of inhaled therapies resulting from the improper design and interpretation of their in vitro and in vivo evaluation. The present study outlines the elements that should be considered in the design, performance, and interpretation of the results of the preclinical evaluation of novel inhaled therapies. These elements are illustrated using an optimized model poly(lactic-co-glycolic) acid (PLGA) microparticle (MP) formulation to optimize the site of MPs deposition. The different expressions of MP size were determined, and their aerosol performance in devices used for animal (Microsprayer® and Insufflator®) and human studies (nebulizer and DPIs) was assessed using inertial impaction. Radiolabeled MPs were delivered to the lungs of rats by spray instillation to determine their site of deposition using single-photon emission computed tomography (SPECT) imaging. Recommendations to optimize the in vitro determinations are given, as well as suggestions to evaluate and interpret in vivo data in the context of the anatomy and physiology of the animal model and the corresponding in vitro data. Recommendations for the proper selection of in vitro parameters to inform in silico modeling are also given, as well as their integration with in vivo data.

Evaluation potentiality of Rhizophora mucronata plantation for pollutants remediation on the Red Sea Coast, Egypt

The planted Rhizophora mucronata was evaluated in two plant ages (one year and eight years) as a biological tool for reducing the mobility of heavy metals in sediments in Safaga and Hamata, Red Sea Coast, Egypt. It is an important region for tourism and nature reserves; however, this area suffers from various anthropogenic contaminants. The ability of mangrove plantations to reduce sediment contamination through bioaccumulation, phytostabilization, or phytoextraction must be clarified through the investigation of metal behavior in mangrove plants and sediments. All of the studied heavy metals had significantly higher concentrations in the Safaga site's sediments. Elder plants had much lower levels of heavy metals in their sediments than younger plants, also rhizosphere samples were less contaminated than non-rhizosphere ones. The order of remediation efficiency was Mo > Ni > Mn ≥ Co > Al > Cu > Zn ≥ Cr > Fe > V, where the highest % was 99.25, 58.97, 42.64, 42.48, 41.91, 39.47, 37.93, 37.01, 36.89, and 29.44, respectively. R. mucronata parts were more significantly contaminated with Co, Cr, Cu, Mo and Zn in Safaga site, while at the Hamata site, they were more significantly contaminated with Al, Fe, Mn, Ni, and V. The elder plants accumulated higher concentrations than younger ones and the contents of heavy metals in plant samples followed the order of root > aerial roots > shoot. Bioconcentration factor (BCF) values representing the accumulation efficiency of R. mucronata were Ni > Mo > Zn > Cu > Cr > Co > Mn ≥ Al > V > Fe, where their highest values were 17.74, 7.89, 3.95, 3.84, 2.66, 1.91, 1.67, 1.66, 1.6, 1.18, respectively. BCF values exceeded one for all metals and values of translocation factor (TF) were less than unity in all cases, thus Rhizophora mucronata can be considered as a good phytostabilizer of ten studied heavy metals able to reduce their mobility through accumulation by roots, thereby reducing off-site contamination.

Determining deposits on knit fabrics, yarns, and fibers, from sensor-related treatments

Creation of a knit fabric-based, stable sensor using dipping and encapsulation processes is feasible, but where deposition occurs in the structure is not yet well understood. Using two graphene treatments and three encapsulants applied to single jersey (100% wool, 100% cotton), relative merits of a range of surface characterization tools (e.g., photographic - optical microscopy, scanning electron microscopy, image analysis (pixel intensity, fiber dimensions), change in lightness (L*, ΔL*, ΔE),) and chemical tools (e.g. vibrational spectroscopy - infrared and Raman) were applied to determine evidence of the treatments. Fabrics, yarns extracted from the treated fabrics and fibers from yarns were each examined. Structure of the fabric, yarns in the fabric, and fibers in the yarns remained clearly identifiable using microscopic methods, suggesting these physical features were largely unchanged. With respect to probable chemical composition, Raman analysis was found preferable to FTIR. HIGHLIGHTS Conferring electrical conductivity directly on knit fabric by simple dipping and stabilizing is feasible. Deposition sites of graphene-related treatments and encapsulants have been identified, with some observed differences dependent on structure, whether fabric, yarn, or fiber. Photographic images (optical, SEM), and FTIR and Raman spectra provide evidence, with Raman superior to FTIR.

Assessment of heavy metals contamination of sediments and surface waters of Bitter lake, Suez Canal, Egypt: Ecological risks and human health

The concentrations of heavy metals in the surface waters and sediments of Bitter Lake were investigated to assess the level, distribution, and source of pollution and the associated ecological and human health risks. The ecological indices of the lake water indicate low contamination degrees by heavy metals. A dermal exposure-based health risk evaluation revealed no carcinogenic or non-carcinogenic impact on human health. The contamination factor (CF) for Cu, Ni, Pb, Mn, Fe, and Zn (CF < 1) indicate low contamination levels, while Cd reaches very high contamination in most sediment sites (CF ranges from 6.2 to 72.4). Furthermore, the potential ecological risk factor (Eri) and modified hazard quotient (mHQ) indicate low ecological risk for all metals except Cd, revealing high to very high-level ecological risk in most sites (Eri ranges from 185 to 2173 and mHQ from 1.8 to 6.3). This emphasizes the urgency of prompt actions to improve the environment in Bitter Lake.

Thymus mast cells as a component of neuro-endocrine-immune interactions under stress

Mast cells (MCs) are a required component of the thymus microenvironment. They affect intercellular interactions and permeability of the hematothymic barrier through cytokine production. There is speculation that the thymus is the site of MCs formation and deposition. MCs are under complex neuro-endocrine control and they can play an important role in the process of acute transformation of the thymus in the formation of a stress reaction, affecting the extrathymic migration of cells. The purpose of this study is to assess the functional involvement of MCs in the process of the thymus acute transformation at various hyper- and hypodynamic effects during the formation of stress response and without it.The study was conducted on male Wistar rats. The stress factors were physical activity (swimming) of different intensities and immobilization, which represent two opposite states of dynamic stress. MCs were classified on histological preparations; a degranulation coefficient and a mean histochemical coefficient (synthetic activity) were calculated.In groups with preserved adrenal glands after exposure a significant decrease in the thymus mass coefficient is noted, which indicates a weakening of its functional activity in response to the development of stress. At the same time, MCs of the thymus quickly respond to neuro-endocrine factors under stress. These cells are involved in a general reaction: their activity consists in a synchronous decrease of the synthesis of granules in the cytoplasm and an increased release of active substances accumulated earlier. The mass and structure of the thymus remain unchanged in groups with removed adrenal glands after immobilization. No changes in morphofunctional indicators of mast cells were detected either. Experiments with hypo- and hyperdinamic loading of animals with preserved and removed adrenal glands indicate that the MCs response is largely determined by the hypothalamic-pituitary-adrenal axis of the endocrine system. Removal of the adrenal glands (inability to release glucocorticoids) leads to a lack of functional response from the thymus MCs. The stimulating effect of adrenal glucocorticoids on MCs under stress is carried out in combination with other neuro-endocrine factors (catecholamines, corticotropin-releasing hormone, adrenocorticotropic hormone). When this axis is activated and a full-fledged stress reaction is formed by the body, MCs are actively involved in the process of acute transformation of the thymus through cytokine secretion. These is an important condition for the development of adaptation mechanisms by the immune system.

A comparison of 210Pbxs, 137Cs, and Pu isotopes as proxies of soil redistribution in South Spain under severe erosion conditions

PurposeThe use of fallout radionuclides as proxies for the study of soil redistribution processes in semiarid environments of Southern Spain has been restricted to 137Cs. The potential and limitations of alternative proxies such as 239+240Pu and 210Pbxs should be explored given the expected constrains imposed by the features of the study area.Materials and methodsFour soil and one sediment cores were collected in a highly eroded area to test the feasibility of these proxies under demanding conditions. The use of gamma spectrometry and ICP-MS did allow exploring the potential of 210Pbxs and Pu isotopes against the well-established tracer, 137Cs. The activity ratios 239+240Pu/137Cs were explored to evaluate the previous evolution of the sampling sites. Soil redistribution rates were estimated using the model MODERN.Results and discussionDespite all the profiles showed intense perturbation, Pu isotopes showed the highest potential thanks to higher sensitivity and sample throughput. The deviations of 239+240Pu/137Cs inventory ratios (0.012–0.158) from the global fallout average (0.026 ± 0.003) suggest that the sediment core was a deposition site involving alternate episodes of topsoil removal and incorporation from different sources. The calculated erosion rates ranged 34–43 t ha−1 year−1, being in good agreement for 137Cs and 239+240Pu. 210Pbxs was not used due to low-quality data.ConclusionsThe use of Pu as a tracer of soil redistribution processes in semiarid areas seems to be promising even under severe erosion conditions. The use of 210Pbxs is not recommended in this area due to its low concentration.Graphical

Zinc, carbon, and oxygen isotopic variations associated with the Marinoan deglaciation

The "Snowball Earths" were cataclysmic events during the late Neoproterozoic's Cryogenian period (720-635 Ma) in which most, if not all, of Earth’s surface was covered in ice. Paleoenvironmental reconstructions of these events utilize isotopic systems, such as Δ17O and barium isotopes of barites. Other isotopic systems, such as zinc (Zn), can reflect seawater composition or environmental conditions (e.g., temperature changes) and biological productivity. We report here a multi-isotopic C, O, and Zn data set for carbonates deposited immediately after the Marinoan glaciation (635 Ma) from the Otavi Group in northern Namibia. In this study, we chemically separated calcite and non-calcitic carbonate phases, finding isotopically distinct carbon and oxygen isotopes. These could reflect changes in the source seawater composition and conditions during carbonate formation. Our key finding is largescale Zn isotopic variations over the oldest parts of the distal foreslope cap carbonate sections. The magnitude of variation is larger than any found throughout post-snowball cap carbonates to date, and in a far shorter sequence. This shows a heretofore undiscovered difficulty for Zn isotopic interpretations. The primary Zn sources are likely to be aeolian or alluvial, associated with the massive deglaciation related run-off from the thawing continent and a greater exposed surface for atmospheric aerosol entrainment. The samples with the lightest Zn isotopic compositions (δ66Zn < 0.3 ‰) potentially reflect hydrothermally sourced Zn dominating the carbonates’ Zn budget. This finding is likely unique to the oldest carbonates, when the meltwater lid was thinnest and surface waters most prone to upwelling of hydrothermally dominated Snowball Earth brine. On the other hand, local variations could be related to bioproductivity affecting the Zn isotopic composition of the seawater. Similarly, fluctuations in sea-level could bring the depositional site below and above a redoxcline, causing isotopic variations. These variations in Zn isotope ratios preclude the estimation of a global Zn isotopic signature, potentially indicating localized resumption of export production.

Three‐Dimensional Steady‐State Hydraulic Tomography Analysis With Integration of Cross‐Hole Flowmeter Data at a Highly Heterogeneous Site

AbstractHydraulic tomography (HT) has been shown to be a robust approach for the high‐resolution characterization of subsurface heterogeneity. However, HT can yield smooth estimates of hydraulic parameters when pumping tests and drawdown measurements are sparse, thus limiting the utility of characterization results in predicting groundwater flow and solute transport. To overcome this issue, this study integrates cross‐hole flowmeter measurements with HT analysis of steady‐state pumping/injection test data for the three‐dimensional (3‐D) characterization of hydraulic conductivity (K) at a highly heterogeneous glaciofluvial deposit site, which has not been previously attempted. Geostatistical inverse analyses of cross‐hole flowmeter data are conducted to yield preliminary estimates of K distribution, which are then utilized as initial K fields for steady‐state HT analysis of head data. Four cases combining three data types (geological information, cross‐hole flowmeter measurements, and steady‐state head data) for inverse modeling are performed. Model calibration and validation results from all cases are compared qualitatively and quantitatively to evaluate their performances. Results from this study show that (a) geostatistical inverse analysis of cross‐hole flowmeter data is capable in revealing vertical distributions of K at well locations and major high/low K zones between wells, (b) cross‐hole flowmeter data carry non‐redundant information of K heterogeneity compared to geological information and steady‐state head data, and (c) integration of flowmeter data improves characterization results in terms of revealing K heterogeneity details and predicting independent hydraulic test data. Therefore, this study demonstrates the usefulness of cross‐hole flowmeter data in augmenting HT surveys for improved K characterization in 3‐D.

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

Finite Element Modeling of the Cycle Characteristics of Li–O2 Secondary Batteries Considering Surface- and Solution-Route Discharge Reactions

Model-based development is an effective approach in terms of obtaining design guidelines for lithium–oxygen secondary batteries (LOBs). In this study, a model simulating the charge/discharge cycle was developed using the finite element method, which enabled us to investigate the factors governing the cyclability of LOBs by conducting virtual cycle tests. In this modeling, we particularly considered that the discharge can proceed via two different routes: surface and solution routes. As an example demonstrating the usefulness of the virtual tests based on the developed model, we evaluated the effects of changes in parameters related to oxygen transport properties on the deposition and dissolution sites of lithium peroxide (Li2O2) generated in the porous cathode of an LOB via the surface and solution routes, respectively, and hence investigated the effects on the cyclability. The proposed model enables various validations that are extremely difficult to carry out using an experimental approach.