Site Of Deposition Research Articles

Design of symbiosis 3D framework interface for long-life lithium metal batteries

The application of lithium metal in batteries is constrained due to high nucleation potential and uneven deposition. Here, we reported that cellulose film protects lithium by a facile and low-cost method, suitable for high-voltage cathodes in carbonate electrolytes. The cellulose layer can well accommodate the deposited lithium and eliminate volume change in the lithium depositing/stripping processes. Cellulose layer nanofibers are transferred to the surface of lithium foil to form a compact layer of cellulose and lithium metal symbiosis. This can homogenize Li-ions distribution and apply as the lithium deposition sites, decreasing nucleation over potential. The symbiotic layer on the surface of lithium foil has the fast Li+ transmission performance of Li2CO3 and LiF, good electronic insulator capability and strong affinity for Li+, respectively. As a result, Li symmetric cells using the cellulose protected Li exhibited excellent cycling stability over 220 h at 3 mA cm−2. The full cells assembled with a NMC811 cathode (loading of 2.68 mA h cm−2) exhibited high-rate capability and excellent cycle stability, with capacity retention of 71.2 % at 400 cycles.

Metallogenic Model and Prospecting Progress of the Qiandongshan–Dongtangzi Large Pb-Zn Deposit, Fengtai Orefield, West Qinling Orogeny

The Qiandongshan–Dongtangzi large Pb-Zn deposit is located in the Fengxian–Taibai (abbr. Fengtai) polymetallic orefield. The ore bodies primarily occur within and around the contact surface between the limestone of the Gudaoling Formation and the phyllite of the Xinghongpu Formation, which are clearly controlled by anticline and specific lithohorizon. Magmatic rocks are well developed in the mining area, consisting mainly of granitoid plutons and mafic–felsic dikes. Previous metallogenic geochronology studies have yielded a narrow range of ages between 226 and 211 Ma, overlapped by the extensive magmatism during the Late Triassic period in this region. The ω(Co)/ω(Ni) ratio of pyrite in lead–zinc ore ranges from 4.44 to 15.57 (avg. 8.56), implying that its genesis is probably related to volcanic and magmatic-hydrothermal fluids. The δD and δ18O values (ranging from −94.2‰ to −82‰, and 18.89‰ to 20.72‰, respectively,) of the ore-bearing quartz indicate that the fluids were perhaps derived from a magmatic source. The δ34S values of ore-related sulfides display a relatively narrow range of 4.29‰ to 9.63‰ and less than 10‰, resembling those of magmatic-hydrothermal origin Pb-Zn deposits. The Pb isotopic composition of the sulfides from the Qiandongshan–Dongtangzi Pb-Zn deposit (with 206Pb/204Pb ratios of 18.06 to 18.14, the 207Pb/204Pb ratios of 15.61 to 15.71, and 208Pb/204Pb ratios of 38.15 to 38.50) is similar to that of the Late Triassic Xiba granite pluton, suggesting that they share the same Pb source. The contents of W, Mo, As, Sb, Hg, Bi, Cd, and other elements associated with magmatic-hydrothermal fluids are high in lead–zinc ores, and the contents of Sn, W, Co, and Ni are also enriched in sphalerite. The contents of trace elements and rare earth elements in the ore are similar to those in the Xiba granite pluton, and they maybe propose a magmatic-hydrothermal origin as well. As a result of this information, the Qiandongshan–Dongtangzi large Pb-Zn deposit may be classified as a magmatic hydrothermal stratabound type, with the Si/Ca contact area being the ore-forming structural plane. Thus, a mineralization model has been proposed based on a comparative analysis of the geological and geochemical properties of the lead–zinc deposit in the Fengtai orefield. It is considered that the secondary anticlines developed on both wings of the Qiandongshan–Dongtangzi composite anticline are the favorable sites for Pb-Zn deposition. Accordingly, the Si/Ca plane and secondary anticline are the major ore-controlling factors and prospecting targets. The verification project was first set up on the north wing of the composite anticline, and thick lead–zinc ore bodies were found in all verification boreholes, accumulating successful experience for deep exploration of lead–zinc deposits in this region.

A Microfluidic Experimental Method for Studying Cell-to-Cell Exosome Delivery-Taking Stem Cell-Tumor Cell Interaction as a Case.

Cell-to-cell communication must occur through molecular transport in the intercellular fluid space. Nanoparticles, such as exosomes, diffuse or move more slowly in fluids than small molecules. To find a microfluidic technology for real-time exosome experiments on intercellular communication between living cells, we use the microfluidic culture dish's quaternary ultra-slow microcirculation flow field to accumulate nanoparticles in a specific area. Taking stem cell-tumor cell interaction as an example, the ultra-slow microcirculatory flow field controls stem cell exosomes to interfere with tumor cells remotely. Under static coculture conditions (without microfluidics), the tumor cells near stem cells (<200 µm) show quick breaking through from its Matrigel drop to meet stem cells, but this 'breaking through' quickly disappears with increasing distance. In programmed ultra-slow microcirculation, stem cells induce tumor cells 5000 μm far at the site of exosome deposition (according to nanoparticle simulations). After 14 days of programmed coculture, the glomeration and migration of tumor cells were observed in the exosome deposition area. This example shows that the ultra-slow microcirculation of the microfluidic culture dish has good prospects in quantitative experiments to study exosome communication between living cells and drug development of cancer metastasis.

(Invited) Exploitation of Electron Transfer Reactions for Latent Fingerprint Visualization: Fundamental Concepts and Technology Transfer

A fingerprint is a unique time-invariant attribute of an individual and is the most frequent physical evidence used to identify a suspect in a criminal investigation. An image of the fingerprint left on a surface by the transfer of material between the fingertip and the surface can establish contact between the individual and an object (e.g. weapon) or a fixed location (crime scene). In practice, most marks are so-called latent (non-visible) fingermarks that require chemical treatment to generate a visible image. This presentation describes the contribution of electron transfer reactions (redox processes) to this endeavor and reveals the variety of reaction type, reagent materials, and substrate surfaces.The key to a successful fingermark reagent is the facility to deliver it with high spatial selectivity to either the deposited residue (representing ridges on the finger) or the bare substrate (representing furrows on the finger), such that there is visual contrast between the ridge and furrow areas. The lateral (horizontal) patterning of so-called second level features (such as ridge endings, crossovers and bifurcations) is the basis of the identification. Superficially, the distance scale is macroscopic (ridge width ca. 100 mm), but the aspiration of a suitably sharp image involves so-called third level detail at the mesoscopic level (ridge edge shape resolution ca. 1 mm). However, this lateral image quality requires vertical control of reagent deposition at the nanoscale. Here we explore how latent fingermark visualization can be accomplished by controlled molecular mechanisms involving metallic and polymeric materials.Two established (but previously poorly mechanistically understood) metal deposition processes are physical developer (PD) and multi-metal deposition (MMD). PD involves redox generation of silver nanoparticles that deposit selectively on fingermark residue on paper substrates (e.g., documents, correspondence, paper currency). We show how mechanistic understanding [1] of a recent PD re-formulation [2] has been used to overcome the environmental outlawing of a critical surfactant in the classical process, revealing latent marks up to a century after deposition. MMD is a more sophisticated variant, in which gold nanoparticles are pre-deposited on the residue and act as nucleation sites for silver deposition to reveal marks on thin plastic films (e.g., drugs and explosives wrappings). We show how the kinetics of redox-driven silver deposition on ridge vs furrow regions define image contrast.In a complementary strategy, we use the fingerprint residue as a template (“mask”) to direct electrochemically generated reagent to the bare surface between the deposited ridges, creating a negative image of the fingerprint. When the surface is a reactive metal (Cu or Fe), a more noble metal (Ag) can oxidize exposed substrate atoms. The electron transfer process results in solution oxidant (here, Ag) being reduced to elemental metal that deposits on the surface and dissolution of an equivalent amount of substrate. Complexing agents influence both reaction thermodynamics and kinetics. Optical and SEM imaging and EDAX surface analysis reveal high quality images with clear third level detail.When the surface is an inert metal, exemplified by stainless steel (forensically relevant to knife crime), the above galvanic exchange cannot take place. In this instance, electrochemically driven oxidation of aromatic monomers creates negative images of latent marks via polyaniline [3], PEDOT [4] or poly(pyrrole-co-EDOT) [5] films. We show how these electrochromic systems offer the prospect of optimization of visual contrast via light absorption. More recently, we have explored the prospect of incorporating fluorescent dyes (Methyl Red, Methyl Orange, Indigo Carmine, Basic Yellow 40) in the polymer films, using functionalization, ion-exchange and physical encapsulation strategies [6].We discuss the practicalities and prospects for technology transfer of these approaches to the practitioner environment; even for the nominally established PD and MMD processes, this is not trivial. Positive outcomes lie at the core of collaborative expertise provided by practitioners, researchers, regulatory authorities and investigators. We discuss how this can be realized through engagement of these parties and researcher use of the image capture and enhancement technologies used by practitioners.

Evolution of iron and oxygen biogeochemical cycles during the Precambrian.

Iron (Fe) is an essential element for life, and its geochemical cycle is intimately linked to the coupled history of life and Earth's environment. The accumulated geologic records indicate that ferruginous waters existed in the Precambrian oceans not only before the first major rise of atmospheric O2 levels (Great Oxidation Event; GOE) during the Paleoproterozoic, but also during the rest of the Proterozoic. However, the interactive evolution of the biogeochemical cycles of O2 and Fe during the Archean-Proterozoic remains ambiguous. Here, we develop a biogeochemical model to investigate the coupled biogeochemical evolution of Fe-O2 -P-C cycles across the GOE. Our model demonstrates that the marine Fe cycle was less sensitive to changes in the production rate of O2 before the GOE (atmospheric pO2 < 10-6 PAL; present atmospheric level). When the P supply rate to the ocean exceeds a certain threshold, the GOE occurs and atmospheric pO2 rises to ~10-3 -10-1 PAL. After the GOE, the marine Fe(II) concentration is highly sensitive to atmospheric pO2 , suggesting that the marine redox landscape during the Proterozoic may have fluctuated between ferruginous conditions and anoxic non-ferruginous conditions with sulfidic water masses around continental margins. At a certain threshold value of atmospheric pO2 of ~0.3% PAL, the primary oxidation pathway of Fe(II) shifts from the activity of Fe(II)-utilizing anoxygenic photoautotrophs in sunlit surface waters to abiotic process in the deep ocean. This is accompanied by a shift in the primary deposition site of Fe(III) hydroxides from the surface ocean to the deep sea, providing a plausible mechanistic explanation for the observed cessation of iron formations during the Proterozoic.

Enhancing Temperature Adaptability of Aqueous Zinc Batteries via Antifreezing Electrolyte and Site-Selective ZnSe-Ag Interface Layer Design.

Rechargeable aqueous zinc batteries (RAZBs) represent a sustainable, environmentally benign, cost-efficient energy storage solution for the scaled renewable power system. However, the cycling endurance and temperature adaptability of RAZBs are hindered by practical technological barriers such as the subzero freezing point of aqueous electrolyte, severe cation dissolution of the cathode, and dendrite growth on the Zn anode. Herein, we optimize the hybrid electrolyte formulation of 8 M ZnCl2 in the ethylene glycol-water mixed solvent to reconfigure the hydrogen bonding and [Zn(H2O)1.80(EG)0.23]2+ solvation sheath, which well balances the ionic conductivity and the antifreezing property until -125 °C. As monitored by operando X-ray diffraction, meanwhile, the structural dissolution of the V2O5 cathode upon the dynamic cycling and static idling storage at elevated temperature are effectively restrained. At the anode side, the thermally induced substitution between the Ag2Se overcoating and Zn foil in situ constructs the site-selective, mosaic interface layer, in which the solvophilic ZnSe facilitates the desolvation, while the Ag species provide zincophilic nucleation sites for high-throughput Zn deposition. The synergistic coupling of the antifreezing electrolyte and anode interfacial design enables the wide-temperature-range adaptability of the RAZB prototype (10 μm Zn foil and 1 mAh cm-2 V2O5 cathode), which balances the cycling endurance (92.5% capacity retention rate for 1000 cycles), 84.7% mitigation of the self-discharge rate at 55 °C, as well as the secured cyclability even at -40 °C.

Biosurfactant-affected mobility of oxytetracycline and its variations with surface chemical heterogeneity in saturated porous media

Herein, the influences of rhamnolipid (a typical biosurfactant) on oxytetracycline (OTC) transport in the porous media and their variations with the surface heterogeneities of the media (uncoated sand, goethite (Goe)-, and humic acid (HA)-coated sands) were explored. Compared to uncoated sand, goethite and HA coatings suppressed OTC mobility by increasing deposition sites. Interestingly, rhamnolipid-affected OTC transport strongly depended on the chemical heterogeneities of aquifers and biosurfactant concentrations. Concretely, adding rhamnolipid (1–3 mg/L) inhibited OTC mobility through sand columns because of the bridging effect of biosurfactant between sand and OTC. Unexpectedly, rhamnolipid of 10 mg/L did not further improve the inhibition of OTC transport owing to the fact that the deposition capacity of rhamnolipid reached its maximum. OTC mobility in Goe-coated sand columns was inhibited by 1 mg/L rhamnolipid. However, the inhibitory effect decreased with the increasing rhamnolipid concentration (3 mg/L) and exhibited a promoted effect at 10 mg/L rhamnolipid. This surprising observation was that the increased rhamnolipid molecules gradually occupied the favorable deposition sites (i.e., the positively charged sites). In comparison, rhamnolipid facilitated OTC transport in the HA-coated sand column. The promotion effects positively correlated with rhamnolipid concentrations because of the high electrostatic repulsion and deposition site competition induced by the deposited rhamnolipid. Another interesting phenomenon was that rhamnolipid's enhanced or inhibitory effects on OTC transport declined with the increasing solution pH because of the decreased rhamnolipid deposition on porous media surfaces. These findings benefit our understanding of the environmental behaviors of antibiotics in complex soil-water systems containing biosurfactants.

Utilizing Remote Sensing and Satellite-Based Bouguer Gravity data to Predict Potential Sites of Hydrothermal Minerals and Gold Deposits in Central Saudi Arabia

This article aims to aid in exploring and forecasting hydrothermal minerals and gold deposits in Central Saudi Arabia (SA), with a focus on structural contexts. Remote sensing (RS) and satellite-based Bouguer gravity (SBG) data were integrated in order to create a mineral prediction map for the researched location. Data from the Landsat Operational Land Imager (OLI) and Shuttle Radar Topography Mission (SRTM) were transformed and enhanced using a variety of approaches. The delineation of hydrothermal alteration zones (HAZs) and highlighting of structural discontinuities in the OLI data were made possible using band ratios and oriented principal component analysis (PCA). Additionally, the underlying structural features were successfully exposed by processing the SBG using a variety of edge detection techniques, like the analytical signal (AS), total horizontal derivative (THD), tilt angle (TA), horizontal tilt angle (TDX), theta map (TM), horizontal derivative of the tilt derivative (HD_TDR), horizontal gradient of the tilt angle (HGTA), tilt angle of the analytical signal (TAAS), and soft sign function (SF). As a result, more prominent lineaments were found in the NW–SE, NNW–SSE, NE–SW, and NNE–SSW directions than in the N–S and E–W directions. The GIS incorporated surface/subsurface geological structure density maps with zones of hydrothermal alteration. It was found that the lineaments derived from the analysis of the RS and SBG data were more in line with the HAZs, which demonstrated the common connection between alteration zones and deep lineaments. The findings revealed a mineral prediction map with extremely low to extremely high probabilities. Overall, combining RS and SBG data effectively identified probable mineralization sites associated with hydrothermal processes and made it easier to create this study’s final predictive mineralization map.

A novel ligand protection strategy based on lacunary polyoxometalate to precisely construct CoMoS active sites for hydrodesulfurization

Efficient CoMoS catalysts with intimate bimetallic synergy are derived from cobalt-substituted phosphomolybdate and exhibited excellent hydrodesulfurization (HDS) activity. Based on ligand protection strategy, the introduction of pyridine ligands onto the vacancies of the trivacant polyoxometalates (POMs) successfully overcame their low stability and isomerization behavior in solution. Subsequently, Co2+ was anchored in the molecular skeleton of [A-α-PMo9O31(py)3]3− (PMo9-py) to form CoxPMo9-py precursors with high Co/Mo ratios, which enhanced the reducibility of Mo species and transformed them to abundant CoMoS active phase during sulfidation process. The quenching effect of pyridine molecules on the acidic sites of support and carbon deposition generated in the high temperature sulfidation weakened the strong metal-support interactions (SMSI) while improving the dispersion and sulfidation of active metals. Due to the unique structure of CoxPMo9-py, the CoMoS phase with high dispersion, efficient synergy and high concentration was obtained. The combination of POMs precursors and pyridine ligands enabled the S-CoxPMo9-py/Al2O3 catalyst to achieve up to 99.5% conversion of dibenzothiophene (DBT).

Building block effect induces horizontally oriented bottom Zn(002) deposition for a highly stable zinc anode

The practical application of zinc anodes for rechargeable aqueous zinc-ion batteries is hindered to uncontrollable dendritic zinc deposition and side reactions. And the deposition of zinc is like building blocks layer by layer, typically considered as nucleation, growth and evolution driven by electric field. Yet the important role of the bottommost deposits is generally ignored. Here, we developed a highly self-adaptable polydimethylsiloxane (PDMS)/montmorillonite (MMT) film to regulate the process of zinc deposition sustainably. In the nucleation and growth stages of zinc, the two-step regulation of the building block effect benefits from the adsorption of oxygen-containing sites on PDMS and fast zinc ion nanochannels in the negatively charged interlayer of MMT to achieve targeted-capture of zinc ions and ordered-deposition, thus inducing horizontally oriented Zn(002) deposition in the initial nucleation layer and providing a flat deposition site for the subsequently deposited metal. In the evolutionary stage of Zn, the PDMS/MMT (PMZn) interfacial layer can achieve a conformal contact with the anode due to the high dynamic adaptability and self-healing of the micro-crosslinking of Si-O-Si and B-O bonds. Consequently, PMZn@Cu||Zn offers higher coulombic efficiency(CE) (99.77%) and the PMZn@Zn anodes exhibit an ultra-long cycle life of 2000 h, more than 10 times that of bare zinc anodes. The stability of the high capacity of PMZn@Zn||MnO2 full cells far exceeds that of Zn||MnO2. This strategy provides an effective approach to develop a stable Zn metal anode for aqueous rechargeable Zn batteries.

Sulfur-vacancy-enriched MoS2-CNTs with highly dispersed Au particles for sensitive dopamine detection

Introducing targeted surface defects sites to regulate the electronic structure is a key method to enhance the electrocatalytic activity of materials. This study reports an electrochemical dopamine sensor using sulfur vacancy (Sv) rich MoS2-CNTs with coaxial hierarchical structure and highly dispersed active gold particles (Au-Sv-MoS2-CNTs). MoS2 with sulfur vacancies expands the layered structure beyond the MWCNT's cylinder rather than being restricted to its surface and has active Au deposition sites along the edges. With optimal conditions, the proposed coaxial, hierarchical-structured Au-Sv-MoS2-CNTs show remarkable detection performance for the rapid detection of DA at concentrations as low as 2 nM in phosphate buffered saline (PBS). In addition, the sensor selectivity and anti-interference qualities are evaluated using chronoamperometry. Furthermore, it successfully detected the analyte from injection of dopamine hydrochloride and bovine serum samples with recovery rates ranging from 99.3% to 102.6% and relative standard deviations (RSD) less than 5%. Density functional theory (DFT) simulations demonstrate that the modifications of Sv and Au NPs could tune the electronic structure of the sensor and facilitate the adsorption and electrocatalytic reaction of DA on Au-Sv-MoS2-CNTs. This study reveals that vacancy engineering and morphology control are emerging strategies for the fabrication of biosensors.

Correlation analysis of the abdominal visceral fat area with the structure and function of the heart and liver in obesity: a prospective magnetic resonance imaging study

BackgroundThe differences in fat deposition sites exhibit varying degrees of systemic inflammatory responses and organ damage, especially in obese individuals with excessive visceral fat. Visceral fat, which is closely related to an increase in mortality rates related to heart and liver diseases. However, few studies have analysed the differences in heart and liver indicators and their correlation among groups based on the abdominal visceral fat area (AVFA).ObjectiveClarifying the differences in and correlations of heart and liver indicators among groups with different severities of AVFA by magnetic resonance imaging (MRI).MethodsSixty-nine subjects with obesity were enrolled. The study group consisted of forty-one individuals (AVFA ≥ 150 cm2), and the control group consisted of twenty-eight individuals (100 cm2 ≤ AVFA < 150 cm2). The differences in and correlations between clinical, laboratory, and MRI indicators of the heart and liver between the two groups were analysed.ResultsIn the study group, the incidences of type 2 diabetes mellitus (T2DM) and insulin resistance were higher, and liver function indicators were worse. The left ventricular eccentricity ratio (LVER), left ventricular mass (LVM) and global peak wall thickness (GPWT) were higher in the study group than in the control group (P = 0.002, P = 0.001, P = 0.03), and the left ventricle global longitudinal strain (LVGLS) was lower in the study group than in the control group (P = 0.016). The pericardiac adipose tissue volume (PATV) and myocardial proton density fat fraction (M-PDFF) were higher in the study group than in the control group (P = 0.001, P = 0.001). The hepatic proton density fat fraction (H-PDFF) and abdominal subcutaneous fat area (ASFA) were higher in the study group than in the control group (P < 0.001, P = 0.012). There was a moderate positive correlation (ρ = 0.39–0.59, P < 0.001) between the AVFA and LVER, LVM, GPWT, LVGLS, and H-PDFF. There was no difference in right ventricular and most left ventricular systolic and diastolic function between the two groups.ConclusionThe high AVFA group had a larger LVM, GPWT and PATV, more obvious changes in LVER, impaired left ventricular diastolic function, an increased risk of heart disease, and more severe hepatic fat deposition and liver injury. Therefore, there is a correlation between the amount of visceral adipose tissue and subclinical cardiac changes and liver injury.

Five hoards in eighty years. Landscape perspectives on new Bronze Age hoard finds around Lake Mälaren in Sweden

Abstract Since 1941, only five Bronze Age hoards have been found in the four provinces around Sweden’s Lakes Mälaren and Hjälmaren: three in Uppland, two in Södermanland, none in Västmanland or Närke. The most recent one appeared in 2016. Here each hoard is discussed in terms of its date, the regional affiliation of its contents, and its landscape situation. They all date from Per. V–VI, c. 950–520 cal BC, and are entirely dominated by locally made objects. Two sites are apparently peripheral in relation to period settlement and to other deposition sites, while two are in an area of dense settlement and were found during the same military metal detector campaign. The steep drop in new hoard finds after World War II is discussed, and Sweden’s restrictive metal detector legislation is identified as the main reason that only five hoards have come to light in the area over the past eighty years.

Constructing rich-Zn Pt1Zn1 alloy over the BEA zeolite as a selective catalyst for propane dehydrogenation

The deactivation of Pt-based catalysts is the most critical problem in nonoxidative propane dehydrogenation reaction (PDH), usually manifested in carbon deposition and active site sintering. Zn, as another cheap metal with more abundant reserves than Sn, is also widely used as an assistant in Pt-based catalysts. However, both of them are easy to be reduced to metal valence state and lost in the reaction process. Herein, the enlarged quantities of Zn are applied in the bimetallic Pt-Zn catalyst preparation. As confirmed by the increased reduction temperature of oxidized Zn species, it effectively minimizes the influence of the active metal mobility caused by Zn loss. At the same time, the constructed bimetallic structure modulates the surface acidity of Zn species and presents benign propylene desorption ability, thus the formed highly dispersed Pt sites on the surface of Pt1Zn1 alloy are well-matched with its high propylene selectivity (∼98.6%). In addition, the rich-Zn Pt1Zn1 sites are beneficial for enhancing the capability of resisting-coke, thus retarding the deactivation of this catalyst.

Impact of Sedimentary Conditions and Relative Distribution of Sand Sedimentary Minerals in Iraqi Soils

This study investigated the relative distribution of sand-separating minerals and the effect of sedimentary and climatic conditions on their distribution in some soils from northern and southern Iraq. The samples were collected from four Iraqi governorates: Erbil (included the soils from areas of Shaqlawa, Soran, and Juman), Sulaymaniyah (included the soils from Dokan, Sayed Sadeq, and Halabja), Maysan (included the soils of Al-Kahla, Ali Al-Sharqi, Awasha, Kumit, Ali Al-Gharbi, and Al-Tayyib), and Wasit Governorate (included the soils of Zurbatiya, Badra, Jassan, Al-Muwafiqiyah, Al-Numaniyah, and Zubaidiyah). The results indicated that the percentages of light sand minerals were higher than the percentages of heavy sand minerals in all the soils of the study sites. It is attributed to the nature of the mineral composition and the intensity of the weathering factor’s influence on the sedimentation sites or during transportation. The results also indicated the dominance of the quartz group, followed by the group of carbonate rock pieces and the group of feldspar minerals in terms of dominance within the light part of sand minerals in all soil samples in southern Iraq (Wasit and Maysan). The rock-cut minerals group was dominant, followed by the quartz and feldspar minerals group in all soil samples in northern Iraq (Erbil and Sulaymaniyah). The other light minerals of the group were found in varying proportions and distribution in all soil samples, which included (mudstone, lime, evaporites, igneous and metamorphic rocks, clay-coated grains, and other minerals). The results showed that the percentages of the opaque minerals were higher in all soil samples than the group of non-opaque minerals, which included minerals (zircon, tourmaline, rutile, strolite, epidote, and kyanite) with irregularity and a significant difference in the proportions as the large percentages indicate that they bear transportation over long distances and their resistance to weathering processes. These ratios were more evident in the northern regions of Erbil and Sulaymaniyah, which indicate the intensity of weathering processes (wet climate) compared to the soils of Wasit and Maysan in southern Iraq. The low percentages appeared in the soil samples due to the short transportation distance and the diversity of the source rocks.

Spatial-temporal tracking of molecular species in Geant4-DNA track structure simulations

Monte Carlo particle transport codes have been used to simulate the radiolysis of water and subsequent evolution of molecular species during the chemical stage. In Geant4, accounting of molecules is performed using a molecule counter which provides only a global molecule count. We developed a modular counter implementation that was used to perform spatial-temporal tracking of molecule counts. This custom counter was validated in homogeneous and simplistic split geometries for 1 MeV electrons and 50 MeV protons.Using a spherical cell with one nucleus and one hundred mitochondria as an example, the radiolytic yields in the cytoplasm, nucleus, and mitochondria were compared between targeted (electrons originating from within mitochondria) and unspecific (electrons originating from within cytoplasm) for (very) low energy electrons with kinetic energies of 100 eV to 1 keV.At short times radiolytic yields in source volumes were consistent with reference yields obtained in a large homogeneous volume. Past 1 ns diffusion out of the source volumes led to yield reductions. For volumes abutting the source volumes radiolytic yields at short times strongly depended on track end effects, most pronounced for 100 eV electrons. Similarly, diffusion out of the source volumes greatly increased yields in abutting volumes past 1 ns with magnitude decreasing and time of increase increasing with increasing electron energy. For higher energy electron beams (100 keV and 200 keV) radiolytic yields in all volumes were consistent with reference yields for large statistics.Thus, in cases where energy deposit sites are uniformly distributed in the volume of interest and energies of the charged particles are high to avoid track end effects reference yields may be used in place of resource intensive chemical stage simulations. Spatially heterogeneous energy deposits, as observed in targeted ɑ or β radiation therapy or with targeted nanoparticles, using a spatially sensitive molecule counter is suggested when estimating radiolytic yields outside of the source volumes or at distances that are within the diffusion range of the molecules of interest.

Amyloid Beta Peptides Lead to Mast Cell Activation in a Novel 3D Hydrogel Model.

Alzheimer's disease (AD) is a prevalent neurodegenerative disease and the world's primary cause of dementia among the elderly population. The aggregation of toxic amyloid-beta (Aβ) is one of the main pathological hallmarks of the AD brain. Recently, neuroinflammation has been recognized as one of the major features of AD, which involves a network of interactions between immune cells. The mast cell (MC) is an innate immune cell type known to serve as a first responder to pathological changes and crosstalk with microglia and neurons. Although an increased number of mast cells were found near the sites of Aβ deposition, how mast cells are activated in AD is not clear. We developed a 3D culture system to culture MCs and investigated the activation of MCs by Aβ peptides. Because collagen I is the major component of extracellular matrix (ECM) in the brain, we encapsulated human LADR MCs in gels formed by collagen I. We found that 3D-cultured MCs survived and proliferated at the same level as MCs in suspension. Additionally, they can be induced to secrete inflammatory cytokines as well as MC proteases tryptase and chymase by typical MC activators interleukin 33 (IL-33) and IgE/anti-IgE. Culturing with peptides Aβ1-42, Aβ1-40, and Aβ25-35 caused MCs to secrete inflammatory mediators, with Aβ1-42 inducing the maximum level of activation. These data indicate that MCs respond to amyloid deposition to elicit inflammatory responses and demonstrate the validity of collagen gel as a model system to investigate MCs in a 3D environment to understand neuroinflammation in AD.

Ten questions concerning indoor ultrafine particles

Ultrafine particles (≤100 nm in diameter) are the smallest condensed-phase materials in air. By number, they are the most abundant particles both outdoors and indoors. Because of their small size, they contribute little to mass concentrations of fine particles, a regulated air pollutant with large associated health risks. Inhaling ultrafine particles raises health concerns, in part owing to their ability to migrate from the site of deposition in the respiratory tract. Buildings provide partial protection against ultrafine particles of outdoor origin. The degree of that protection is broadly variable, influenced by particle size and by building design and operational factors, such as ventilation rates and the efficiency of particle filters. Because of the large proportion of time spent by people indoors, much exposure to ultrafine particles occurs in buildings, even for particles of outdoor origin. Diverse indoor sources, including cooking and the use of candles, contribute materially to indoor ultrafine particle concentrations. Indoor sourced ultrafine particle concentrations are also influenced by building design and operational factors. Whether of indoor or outdoor origin, dynamic processes influence the concentrations, sizes, and chemical composition of ultrafine particles. Such processes include deposition to indoor surfaces, coagulation, and sorptive partitioning of semivolatile organic compounds. Advancing scientific and technical knowledge about building factors and dynamic processes that influence indoor ultrafine particle concentrations can contribute (a) to better understanding of associated health risks and (b) to the more effective design and implementation of mitigation strategies and technologies.

Retention and release of black phosphorus nanoparticles in porous media under various physicochemical conditions

Black phosphorus nanosheets/nanoparticles (BPNs) are widely applied in many fields. However, the transport of BPNs in the subsurface still has not yet been reported and there is increasing concern about potential adverse impacts on ecosystems. Roles of median grain size and surface roughness, BPN concentration, and solution chemistries (pH, ionic strength, and cation types) on the retention and release of BPNs in column experiments were therefore investigated. The mobility of BPNs significantly increased with increasing grain size and decreasing surface roughness due to their influence on the mass transfer rate, number of deposition sites and retention capacity, and straining processes. Transport of BPNs was enhanced with an increase in pH and a decrease in ionic strength because of surface deprotonation and stronger repulsion that tends to reduce aggregation. The BPN transport was significantly sensitive to ionic strength, compared with other engineered nanoparticles. Additionally, charge heterogeneity and cation-bridging played a critical role in the retention of BPNs in the presence of divalent cations. Higher input concentrations increased the retention of BPNs, probably because collisions, aggregation at pore throat locations, and hydrodynamic bridging were more pronounced. Small fractions of BPNs can be released under decreasing IS and increasing pH due to the expansion of the electrical double layer and increased repulsion at convex roughness locations. A mathematical model that includes provisions for advective dispersive transport and time-dependent retention with blocking or ripening terms well described the retention and release of BPNs. These findings provide fundamental information that helps to understand the transport of BPNs in the subsurface environments.

Reconstructing post-mid Pleistocene glacial-dammed paleolakes in the Tsangpo Gorge, southeastern Tibetan Plateau

The paleolakes of the Yarlung Tsangpo Gorge area of the southeastern Tibetan Plateau provide an important basis for testing the hypothesis that glacial dams have effectively prevented the Yarlung Tsangpo River from cutting into the edge of the Plateau. However, sedimentological evidence for the recurrence of these paleolakes during the Quaternary remains inadequate. During this research we conducted extensive geological surveys, and sedimentary and geochronological analyses, of the river terraces and valley sediments upstream of the Yarlung Tsangpo Gorge. Three fluvial-lacustrine terraces formed since the last glacial period were identified from analyses of 17 sedimentary sites, with the following depositional ages, from new to old: 0.6–0.4 ka (T1), 9–5 ka (T2) and ≥50–20 ka (T3), respectively. The sediments of T1 and T2 are <30 m thick with an overall pattern of reversely-graded sequences, each reflecting a dammed paleolake event (named Paleolake I and Paleolake II). The sediments in T3 are the thickest (>265 m), with the highest preserved terraces in the river valley. More than five depositional cycles of fluvial and lacustrine phases in this terrace reflect many sporadic damming events during the last glacial period (representing Paleolake III). Additionally, the earliest phase of sedimentation of the dammed lakes revealed by analyses of drill cores in the valley fill may have begun in the Mid Pleistocene. The sedimentary sequences of these paleolakes revealed that frequent glacial-damming events have occurred in response to climate change since the Mid Pleistocene, supporting the theory that glacial dams and outburst floods have played an influential role in the geomorphological evolution of the margins of the Tibetan Plateau.