Organic Deposition Research Articles

Overcoming Downscaling Limitations in Organic Semiconductors: Strategies and Progress.

Organic semiconductors have great potential to revolutionize electronics by enabling flexible and eco-friendly manufacturing of electronic devices on plastic film substrates. Recent research and development led to the creation of printed displays, radio-frequency identification tags, smart labels, and sensors based on organic electronics. Over the last 3 decades, significant progress has been made in realizing electronic devices with unprecedented features, such as wearable sensors, disposable electronics, and foldable displays, through the exploitation of desirable characteristics in organic electronics. Neverthless, the down-scalability of organic electronic devices remains a crucial consideration. To address this, efforts are extensively explored. It is of utmost importance to further develop these alternative patterning methods to overcome the downscaling challenge. This review comprehensively discusses the efforts and strategies aimed at overcoming the limitations of downscaling in organic semiconductors, with a particular focus on four main areas: 1) lithography-compatible organic semiconductors, 2) fine patterning of printing methods, 3) organic material deposition on pre-fabricated devices, and 4) vertical-channeled organic electronics. By discussing these areas, the full potential of organic semiconductors can be unlocked, and the field of flexible and sustainable electronics can be advanced.

Monodisperse BaZrO3 nanocrystals and flux pinning effect on upscaling MOD-derived (Y,Dy)Ba2Cu3O7− δ superconducting tapes

In the present work, monodisperse BaZrO3 (BZO) nanocrystals with controllable sizes are successfully introduced into trifluoroacetate metal–organic deposition derived (Y,Dy)Ba2Cu3O7−δ ((Y,Dy)BCO)-coated superconducting tapes to act as effective pinning centers. The BZO nanocrystal addition strategy is extended to upscaling coated conductors as long as hundreds of meters, and as thick as 3.4 μm, of (Y,Dy)BCO layers. The corresponding superconducting performances of BZO-added (Y,Dy)BCO-coated conductors are systematically investigated under various applied magnetic fields and temperatures. It is revealed that the I c (77 K, self-field) of BZO-added tapes decreases linearly with BZO concentration, while the corresponding in-field lift-factors increase for all studied BZO additions. In-field J c values under various fields at low temperatures show that the (Y,Dy)BCO tape with 5%-BZO addition exhibits a better performance than that of other concentrations. Besides, this benefit of BZO addition appears identical for both thin and thick samples, as well as for tapes that are hundreds of meters long. The angular dependence of in-field I c also shows that significant improvement occurs in all the studied angular ranges after nanocrystal BZO additions, demonstrating that the nanocrystal addition strategy is of great value for upscaling commercial (Y,Dy)BCO tape for in-field applications.

Abrupt and persistent shutdown of the thermohaline forcing during MIS5e in the Adriatic Sea: Insights from shallow-water sapropel sediments

During the Quaternary, the Eastern Mediterranean Sea (EMS) experienced cyclical events of stagnation driven by natural climate variability. The resulting deoxygenation left well-preserved evidence in the sedimentary record as organic carbon-rich deposits referred to as sapropels. Although drastic modifications in the degree of dense-water formation over the EMS shelves exerted first-order control on the deoxygenation, most of the focus has been traditionally placed on the deep EMS. To provide a shallow-water perspective, here we investigated the sapropel S5 in the Adriatic shelf (borehole PRAD1-2) deposited during MIS5e (129-116 ka). This archive is strategically located in a region where the Northern Adriatic Dense Water (NAdDW) interacts with the seabed before cascading across the continental slope. We used Zr/Rb and MgO/Al2O3 to assess bottom current energy and north-to-south sediment transport dynamics, both regulated by the changes in NAdDW production intensity. In addition, we used stable isotopes (δ13C and δ18O) of foraminifera, redox sensitive elements (U, Mo and Sb), foraminifera assemblages as well as alkenones to reconstruct the paleo-environmental conditions during the S5 formation.Our study provides an unprecedented reconstruction of the physical forcing controlling the deoxygenation during the S5 formation. Results reveal that the shutdown of the NAdDW occurred in a few centuries (0.67 ± 0.22 kyrs), when freshening of surface waters combined with warming of winter temperatures mutually hampered the dense water formation. A few centuries after the NAdDW shutdown, the Adriatic shelf experienced euxinic waters for about 2 kyrs followed by a progressive reoxygenation that lasted 4 kyrs. We explain this second phase as a general recovery driven by increased surface salinity over the EMS combined with winter cooling. This favoured surface water mixing without, however, producing dense water in the Northern Adriatic and thus collectively the interruption of the dense water production lasted for 6 kyrs since the onset of MIS5e. Overall, our finding highlights that the thermohaline forcing responded to climate change much quicker than inferred by earlier studies that suggested instead a millennial-scale prelude necessary to develop stagnation. In addition, our results provide solid evidence about the large-scale impact of the deoxygenation during S5 that is capable of invading the continental shelf. Comparison with the latest regional models illustrates how none of the future simulations covering different climate change scenarios reproduces an event over the EMS margins comparable with what described in this study.

Better biocompatibility of nitrogen-doped graphene compared with graphene oxide by reducing cell autophagic flux blockage and cell apoptosis.

Nitrogen-doped graphene (C2 N), a novel graphene-based materials, has been proposed as a potential alternative to graphene oxide (GO) in biomedical applications. However, due to the challenges in synthesizing C2 N, reports in the biomedical field are currently rare. Here, we have modified the reported procedure and successfully synthesized C2 N nanoparticles at 120°C, which we refer to as C2 N-120. The toxicity and biocompatibility of GO and C2 N-120 were evaluated using a mouse model injected with GO/C2 N-120 via the tail vein, as well as cell models treated with GO/C2 N-120. In vivo studies revealed that GO/C2 N-120 showed similar distribution patterns after tail vein injection. The liver, spleen, and lung are the major nanoparticle uptake organs of GO and C2 N-120. However, GO deposition in the major nanoparticle uptake organs was more significant than that of C2 N-120. In addition, GO deposition caused structural abnormalities, increased apoptotic cells, and enhanced macrophage infiltration whereas C2 N-120 exhibited fewer adverse effects. In vitro experiments were conducted using different cell lines treated with GO/C2 N-120. Unlike GO which induced mitochondrial damage, oxidative stress, inflammatory response, autophagic flux blockage and cell apoptosis, C2 N-120 showed lower cytotoxicity in cell models. Our data demonstrated that C2 N-120 exhibits higher biocompatibility than GO, both in vivo and in vitro, suggesting its potential for biomedical application in the future.

Insight into the effect mechanism of sedimentary record of polycyclic aromatic hydrocarbon: Isotopic evidence for lake organic matter deposition and regional development model

Deciphering the temporal patterns of polycyclic aromatic hydrocarbons (PAHs) in sediment cores, and the effect mechanism of sedimentary organic matter (OM) and regional development model on PAHs are crucial for pollution control and environmental management. Herein, sediment core was collected from Chenhu international wetland in Wuhan, central China. Meanwhile, historical trend and source of PAHs and sedimentary OM were presented, respectively. Result demonstrated that the most significant growth of PAHs (increased by 158.8%) was attributed to the significant enhancement of traffic emission (5.57 times), coal combustion (4.59 times), and biomass burning (8.09 times). Similarly, the percentage of phytoplankton (stage Ⅲ: 37.9%; stage Ⅳ: 31.2%) and terrestrial C3 plants (stage Ⅲ: 24.6%; stage Ⅳ: 29.2%) to sedimentary OM hold the dominant position after the stage Ⅱ. The obvious shifts of historical trend and sources in PAHs were highly related to economic development models (r = 0.72, p < 0.001) and sedimentary OM (r = 0.82, p < 0.001). It demonstrated that eutrophication of lake accelerated the burial of PAHs. Redundancy analysis results suggested that TOC was dominating driver of sedimentary PAHs (16.56%) and phytoplankton occupied 9.58%. To further confirm the significant role of economic development models, three different historical trends of PAHs in different regions of China were presented. The result of this study provides the new insight into the geochemistry mechanism of lake sedimentary OM and PAHs. Meanwhile, the relationship of regional development model and sedimentary PAHs was highlighted in this study. Significantly, the main environmental implications of this study are as follows: (1) lake eutrophication of phytoplankton OM accelerated the burial of PAHs in lake sediment; (2) economic development models and energy structure significantly influence the sedimentary PAHs. This study highlights the coupling relationship between OM burial and PAHs sedimentation, and the importance of accelerating the transformation of economic energy structure.

Facies association analysis of a Toarcian siliciclastic‑carbonate lacustrine system, Sichuan Basin, China

Globally, considerable coverage has been devoted to marine environment affected by the Jenkyns Event, but little attention has been given to lacustrine system. Here, siliciclastic‑carbonate samples of the Da'anzhai Member (J1dn) were examined for petrology and geochemistry in order to evaluate lithofacies characteristics, depositional processes and environmental changes of the palaeo-Sichuan lacustrine basin contemporaneous with the Jenkyns Event. Unique sedimentological and petrological features were used to identify five principal facies associations (FA) and depositional environments, including the distal delta front, accretionary bioclastic shoals, proximal bioclastic shoal ramp, distal bioclastic shoal ramp and (semi-)deep lacustrine environment. The vertical transitions of FA reveal that J1dn forms a complete lacustrine transgressive-regressive sedimentary system during the Toarcian, which can be further divided into 3 units in combination with standard gamma logging. The lower unit is characterised by frequent intermixing of multiple FA interpreted as frequent lake-level fluctuations. The middle unit is characterised by the deposition of clay-rich mudstone and the demise of bioclastic shoals interpreted as intensive lacustrine transgression that were at times affected by storm-induced waves or oscillatory currents coinciding with the initiation of the Jenkyns Event. The upper unit is characterised by the thicker and higher proportion of biogenic carbonate-rich lithofacies interpreted as the lake regression, contemporaneous with the end of the Jenkyns Event. Overall, clay-rich lithofacies from suspension settling, turbidity current or slumping triggered by storm events were deposited during a high relative lacustrine-level, accompanied by organic carbon-rich deposition and preservation. In contrast, carbonate-rich lithofacies were mainly controlled by biogenic carbonate sedimentation, associated with a low relative lacustrine-level unconducive to organic matter accumulation. Finally, the proposed depositional evolution model at the lake-level highstand stage and lowstand stage of the palaeo-Sichuan lacustrine basin provides new insights and understanding on the changing palaeolimnological history of the Toarcian lacustrine system.

Using sedimentary prokaryotic communities to assess historical changes in the Gippsland Lakes

Abstract The Gippsland Lakes is the largest estuarine system in Australia. Over the last 2 centuries, this unique aquatic ecosystem has suffered substantial modifications mostly associated with anthropogenic impacts, including the creation in 1889 of an artificial channel to the ocean after European arrival, creating chronic salinisation in the system. However, the biological impacts of this historic shift are unclear. Here, we use shotgun metagenomics of environmental DNA from historical sediments of Lake King and Lake Victoria to detect ancient microbial DNA and track past ecological changes in prokaryotic communities. Sedimentary prokaryotic communities changed with core depth, organic matter levels and European arrival. Specifically, we observed an increase in sulfate‐reducing bacteria (e.g., Desulfobacterales) and organic matter enrichment in the upper layers of the sediment cores of the Gippsland Lakes, which could reflect a period of eutrophication caused by higher rates of organic deposition and marine intrusion post‐European arrival. However, while some species presented authentic ancient DNA signals, the shifts in community composition probably reflect changes in indigenous sediment‐dwelling microorganisms in response to geochemical changes of the sediment. Overall, these observations suggest that historic waterway management practices may influence microbial systems today and that sedimentary microbial communities can change in response to both natural biogeochemical dynamics along the depth profile and past environmental conditions.

Improvement of electrical properties by insertion of AlGaN interlayer for N-polar AlGaN/AlN structures on sapphire substrates

In this study, we propose nitrogen-polar (N-polar) Al0.1Ga0.9N/Al0.9Ga0.1N/aluminum nitride (AlN) structures. N-polar Al0.1Ga0.9N/Al0.9Ga0.1N/AlN was grown on a sapphire substrate with a misorientation of 2° with respect to the m-axis using metal–organic vapor deposition. The effects of varying the Al0.9Ga0.1N interlayer thickness from 30 nm to 1 μm using pulsed H2 etching on the planarity and current–voltage characteristics of the samples were investigated. The current first improved upon increasing the interlayer thickness from 30 to 300 nm, owing to the reduction in interfacial impurities between (aluminum) gallium nitride (Al)GaN) and Al0.9Ga0.1N, but subsequently decreased upon further increasing the thickness because of the relaxation growth of the interlayer. Furthermore, pulsed H2 etching of the Al0.9Ga0.1N interlayer suppressed step bunching and improved planarity. Subsequently, the proposed method was employed to fabricate N-polar Al0.1Ga0.9N/Al0.9Ga0.1N/AlN heterostructure FETs, which demonstrated five times higher source-drain current (I DS) than that of conventional structures without an interlayer.

Dual functions of light-emission and light-harvesting using organic donor and acceptor co-deposition

The device working principles of light emission and light harvesting using p-n (or donor-acceptor) heterostructures are reciprocal relations in terms of thermodynamics and charge transfer mechanisms. The dual-functional optoelectronic systems of organic light-emitting diodes (OLEDs) and organic photovoltaic cells (OPVCs) including organic photodiodes (OPDs) were obtained by fabricating the devices with bi-layer (BL) and triple-layer (TL) structures through the co-deposition of p-type rubrene and n-type NDI-C6 molecules using organic molecular beam deposition. The concentration ratio of rubrene:NDI-C6 for the co-deposition layers (CDLs) was controlled by deposition rates of 3:7, 5:5, and 7:3, resulting in the distinctive performance of the devices. The OLEDs with rubrene/CDL 3:7/NDI-C6 TL structures show considerably broad and enhanced electroluminescence emission by approximately 40 times including a drastic increase in the exciplex EL peak at 695 nm, compared to those of the OLEDs with rubrene/NDI-C6 BLs or other TL structures. As the concentration of n-type NDI-C6 in the CDL increased, the driving voltage decreased, and the current increased for the OLED with the TL structure. The fill factor and power conversion efficiency of the OPVCs and photodetectivity using the same devices increased with increasing concentration of n-type NDI-C6. The dual performance of the OLED and OPVC, including the OPD of the elaborated co-deposition of organic molecules, was clearly observed, even though the efficiencies of the devices were relatively low. In our optoelectronic devices, the optimal concentration ratio of p-type rubrene and n-type NDI-C6 of the CDL in the TL devices was 3:7 for the dual function of light emission and light harvesting.

Waist circumference is independently associated with liver steatosis and fibrosis in LMNA-related and unrelated Familial Partial Lipodystrophy women

BackgroundLipodystrophies are a heterogeneous group of diseases characterized by the selective loss of subcutaneous adipose tissue and ectopic fat deposition in different organs, including the liver. This study aimed to determine the frequencies of liver steatosis (LS) and liver fibrosis (LF) in a sample of individuals with LMNA-related and unrelated Familial Partial Lipodystrophy.MethodsThis cross-sectional study included 17 women with LMNA-related FPLD and 15 women with unrelated FPLD. LS and LF were assessed using transient elastography (TE) with FibroScan®. Anthropometric and biochemical variables were included in a multiple linear regression analysis to identify the variables that were independently related to liver disease.ResultsRegarding the presence of LF, 22 (68.2%) women were classified as having non-significant fibrosis, and 10 (31.8%) were classified as having significant or severe fibrosis. Regarding LS, only six women (20.7%) were classified as having an absence of steatosis, and 23 (79.3%) had mild to severe steatosis. After multiple linear regression, waist circumference (but not age, body mass index, or waist-to-hip ratio) was found to be independently related to LS and LF. Among the biochemical variables, only triglyceride levels were independently related to LS but not LF.ConclusionsIn women with FPLD, visceral fat accumulation appears to be the most important determinant of liver disease, including LF, rather than fat scarcity in the lower limbs.

Catalytic ozone oxidation of m-cresol by spirulina biochar-modified perovskite: Catalyst deactivation and in situ regeneration

In this study, a LaFe0.26Mn0.74O3-δ perovskite catalyst modified using spirulina biochar (LFMO-xBiochar) was used to compare the effects of water flushing on the ozonation performance on a pilot scale. The results showed that timely water flushing operation could effectively extend the service life of LFMO-xBiochar and maintain the chemical oxygen demand (COD) removal rate above 60% for nearly 40 h during the reaction. Density functional theory (DFT) calculations showed that the protonated Fe, Mn, and oxygen vacancies on the catalyst surface were the main active sites. Combined with SEM/EDS mapping, BET, FTIR and XPS measurements, the results showed that organic pollutants and deposits hindered the ozone decomposition at the active sites on the catalyst surface, leading to its final deactivation. However, timely water flushing could effectively remove the organic pollutants and inorganic salts adsorbed onto the catalyst surface during the initial deactivation stage. Additionally, water flushing loosened or removed surface deposits, re-exposing the active sites and restoring some pores, thereby promoting the catalyst regeneration and prolonging its service life. This study provides new insights into the deactivation and regeneration of ozonation catalysts, which can support practical industrial applications of this process.

Abstract P118: The Promotion Of Cardiac Dysfunction By Resiquimod-accelerated Systemic Lupus

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease characterized by autoantibody formation and immune complex deposition in target organs. Individuals with SLE are more than twice as likely to experience a cardiovascular event than the rest of the population, contributing to the increased morbidity and mortality of individuals with this disease. While this increased risk of cardiovascular events in lupus is well known, SLE-specific phenotypes and mechanisms remain unknown. Therefore, we hypothesized that inducing the acceleration of SLE would lead to higher incidence of cardiovascular pathology in a lupus-prone murine model. To test this hypothesis, we treated female B6.Nba2 mice aged 10-14 weeks with Resiquimod (R848; 100μg/30μL), a TLR7/8 agonist shown to induce SLE, twice weekly for four weeks. The mice were followed with echocardiography every 4 weeks, up to 16 weeks. By 16 weeks, organs were harvested, weighed, and fixed or frozen for analysis. Echocardiographic imaging found left ventricular wall thickening 4 weeks after the start of R848 treatment. This was followed by a progressive increase in left ventricular internal dimensions, and a simultaneous decrease in ejection fraction (39.95 ± 0.05 vs 57.68 ± 1.12, p=0.0007) over the course of 16 weeks, culminating in significant cardiac dysfunction compared to vehicle controls. Moreover, tissue harvest revealed significant cardiomegaly (p&lt;0.0001), as well as a four-fold increase in spleen weight of R848-treated mice compared to their vehicle treated counterparts. Furthermore, we investigated the mechanosensitive cation channel Piezo1 by protein and gene expression in cardiac tissues, and found that R848 acceleration of SLE significantly increased protein expression in the heart (1.37 ± 0.13 vs 1.00 ± 0.05, p=0.0208). Our data demonstrates that R848-accelerated SLE in female, lupus-prone B6.Nba2 mice does increase the occurrence of cardiac pathology compared to vehicle controls, and revealed potential for a Piezo-1 mechanism for cardiac dysfunction in Systemic Lupus. These findings present potentially new insight into the development of SLE-associated cardiovascular dysfunction.

Metabolic profiling of urinary exosomes for systemic lupus erythematosus discrimination based on HPL-SEC/MALDI-TOF MS.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease which leads to the formation of immune complex deposits in multiple organs and has heterogeneous clinical manifestations. Currently, exosomes for liquid biopsy have been applied in diagnosis and monitoring of diseases, whereas SLE discrimination based on exosomes at the metabolic level is rarely reported. Herein, we constructed a protocol for metabolomic study of urinary exosomes from SLE patients and healthy controls (HCs) with high efficiency and throughput. Exosomes were first obtained by high-performance liquid size-exclusion chromatography (HPL-SEC), and then metabolic fingerprints of urinary exosomes were extracted by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with high throughput and high efficency. With the statistical analysis by orthogonal partial least-squares discriminant analysis (OPLS-DA) model, SLE patients were efficiently distinguished from HCs, the area under the curve (AUC) of thereceiver characteristic curve (ROC) was 1.00, and the accuracy of theunsupervised clustering heatmap was 90.32%. In addition, potential biomarkers and related metabolic pathways were analyzed. This method, with the characteristics of high throughput, high efficiency, and high accuracy, will provide the broad prospect of exosome-driven precision medicine and large-scale screening in clinical applications.

A critical re‐analysis of constraints on the timing and rate of Laurentide Ice Sheet recession in the northeastern United States

AbstractWe review geochronological data relating to the timing and rate of Laurentide Ice Sheet recession in the northeastern United States and model ice margin movements in a Bayesian framework using compilations of previously published organic 14C (n = 133) and in situ cosmogenic 10Be (n = 95) ages. We compare the resulting method‐specific chronologies with glacial varve records that serve as independent constraints on the pace of ice recession to: (1) construct a synthesis of deglacial chronology throughout the region; and (2) assess the accuracy of each chronometer for constraining the timing of deglaciation. Near the Last Glacial Maximum terminal moraine zone, 10Be and organic 14C ages disagree by thousands of years and limit determination of the initial recession to a date range of 24–20 ka. We infer that 10Be inherited from pre‐glacial exposure adds 2–6 kyr to many exposure ages near the terminal moraines, whereas macrofossil 14C ages are typically 4–8 kyr too young due to a substantial lag between ice recession and sufficient organic material accumulation for dating in some basins. Age discrepancies between these chronometers decrease with distance from the terminal moraine, due to less 10Be inherited from prior exposure and a reduced lag between ice recession and organic material deposition. 14C and 10Be ages generally agree at locations more than 200 km distal from the terminal moraines and suggest a mostly continuous history of ice recession throughout the region from 18 to 13 ka with a variable pace best documented by varves.

Controls on Surface and Downcore Sedimentary Organic Matter in a Constructed Oyster Reef

Oysters provide a suite of important ecosystem services, and recent research shows that oyster restoration rapidly enhances sedimentary organic carbon deposition. In 2012, an oyster reef enhancement project began in the GTM National Estuarine Research Reserve in Northeast FL, USA. We analyzed the spatial and downcore variability in sedimentary organic matter (OM) and particle sizes in the intertidal zone between the reefs and the marsh, along with oyster reef characteristics, to better understand physical and/or biological influences on sediment. Our data indicate that OM in the top 20 cm of sediment cores was negatively correlated with reef age. Similar decreases in particles &lt;63 μm suggest remobilization of sediment, likely driven by the degradation of the reef structure over its approximately 9-year lifetime. Likewise, a survey of surface sediments showed that adjacent reef structural metrics were the best predictor of sediment OM and particle size. These results highlight the importance of reef structure as a control on sedimentary organic carbon deposition and stability in areas where physical energy is relatively high. This result is discussed in the context of implications for carbon budgets and biogeochemical ecosystem services of oysters as a part of living shorelines.

Paleo-Sedimentary Environments and Controlling Factors for Enrichment of Organic Matter in Alkaline Lake Sediments: A Case Study of the Lower Permian Fengcheng Formation in Well F7 at the Western Slope of Mahu Sag, Junggar Basin

The Lower Permian Fengcheng formation is a significant source of rocks and a reservoir for the Mahu Sag in the Junggar Basin. Recently, the paleo-environment deposition factors of the P1f formation have become a popular research topic. This research was conducted using data from the F7 well of Mahu Sag, based on the geochemical analysis results of TOC (total organic carbon), REE (rare earth elements), and major and trace elements of 53 samples from P1f (Lower Permian Fengcheng formation), and some deposition factors are discussed. The P1f deposition process was classified into four stages based on paleo-environment elemental indicators. This research describes the deposition process of the evolution of alkaline lakes. The early and preliminary stages of alkali lake evolution are considered as late P1f1 to middle P1f2; the paleoclimate of this process was dry, the reduction conditions increased, and the paleo-productivity and lake salinity were enhanced. The terminal stage of alkali lake evolution is considered as late P1f2 to middle P1f3; in this period, the paleoclimate changed with seasonal cycles, resulting in a decrease in water salinity and an increase in oxidation; the paleo-productivity of the alkaline lake was at a medium level. Until the end of P1f3, the salinity of the lake decreased, and the water body became anoxic and weakly alkaline. Furthermore, the research on TOC and sedimentary parameters confirmed that the deposition of P1f organic matter is affected by multiple types of factors. A relatively warm climate, lack of oxygen, fresh water–brackish water, suitable debris flow, and high primary productivity conditions promoted organic matter deposition.

Cleaning deteriorated elements of ammunition: Development of a procedure applied to cartridge cases from the Second World War

Deteriorated elements of ammunition can be found while investigating different types of events. Exposure to adverse environmental conditions may lead to metal alteration (corrosion) or organic material deposition (contaminations) on the exposed elements of ammunition. From a forensic perspective, both types of deterioration pose challenges when observing marks left by the firearms used to discharge the corresponding ammunition (e.g. firing pin, extractor). The longer the time of exposure to the adverse environmental conditions, the more challenging the observation of such marks. A literature review highlighted three previously published restorative methods used to clean deteriorated elements of ammunition. The aim of this research is to develop a cleaning procedure applicable to cartridge cases exposed to adverse environmental conditions, while avoiding the degradation of marks left by the firearms used to discharge the corresponding ammunition. A first batch of 21 brass cartridge cases dating back to the Second World War (WWII) was used to develop a cleaning sequence involving the three methods. The efficiency of each restorative method was qualitatively assessed using optical macroscopy and the Evofinder® ballistic identification system. The developed sequence relies on successive applications of Tickopur® TR 7 (a diluted soft metal cleaner), sulfuric acid and finally Aqua Regia (HCl 37% and HNO3 75%), all of them involving ultrasonic baths. The resulting cleaning sequence was subsequently applied to three batches of Second World War cartridge cases discovered in France and Russia. This sequential procedure allows the effective cleaning of WWII brass cartridge cases while highlighting different marks left by firing pins, extractors, ejectors, and breech faces. Applying a forensic analysis and comparison process to the marks highlighted on these elements of ammunition can support the verification of historical facts when reconstructing events which took place more than seventy years ago.

Freshwater gastropods across the Cretaceous–Paleogene boundary in the Songliao Basin, north-east China

Gastropod faunas from the Cretaceous–Paleogene (K/Pg) boundary transition in the well-dated Songliao Basin (north-east China, East Asia) have been studied. In total, 673 specimens were counted, of which about 80% (n = 538) could be identified. In all, eight species, belonging to six genera, have been identified, including Hydrobia? datangensis, Mesolanistes cf. nanxiongensis, Valvata jiaolaiensis, Valvata shakengensis, Tricula sp. 1, Tricula sp. 2, Zaptychius sp., Planorbidae gen. et sp. indet. and Helisoma dongdawusuensis. Combining data on species ranges in the Jiaolai and Pingyi basins of eastern China, it is shown that three out of 11 species went extinct during K/Pg boundary perturbations. Therefore, we conclude that freshwater gastropods in East Asia underwent minor extinction (c. 18% extinction rates; 72% survival rates). These snail faunas were not affected by short-lived detrimental conditions related to K/Pg boundary perturbations, such as darkness, cooling and starvation, because most of these genera are micro-herbivorous and/or micro-omnivorous grazers (including detritivores) that fed on bacterial films, algae and diatoms or ingested carrion and fine organic deposits. The global mass extinction event at the K/Pg boundary in freshwater environments has rarely been studied, meaning that the present study may help to understand patterns of selective extinction.

Uncovering the processes of microbial community assembly in the near-surface sediments of a climate-sensitive glacier-fed lake

Glacier-fed lakes are characterized by cold temperatures, high altitudes, and nutrient-poor conditions. Despite these challenging conditions, near-surface sediments of glacier-fed lakes harbor rich microbial communities that are critical for ecosystem functioning and serve as a bridge between aquatic ecology and the deep subsurface biosphere. However, there is limited knowledge regarding the microbial communities and their assembly processes in these sediments, which are highly vulnerable to climate change. To fill this knowledge gap, this study systematically analyzed environmental variables, microbial communities, diversity, co-occurrence relationships, and community assembly processes in the near-surface sediments of a glacier-fed lake in the Tibetan Plateau. The results revealed distinct vertical gradients in microbial diversity and subcommunities, highlighting the significant influence of selection processes and adaptive abilities on microbial communities. Specifically, specialists played a crucial role within the overall microbial communities. Microbial assembly was primarily driven by homogeneous selection, but its influence declined with increasing depth. In contrast, homogenizing dispersal showed an opposite pattern, and the bottom layer exhibited heterogeneous selection and undominated processes. These patterns of microbial assembly were primarily driven by environmental gradients, with significant contributions from processes associated to ammonium and organic matter deposition, as well as chemical precipitation in response to a warming climate. This study enhances our understanding of the microbial communities and assembly processes in the near-surface sediments of glacier-fed lakes and sheds light on geo-microbiological processes in climate-sensitive lacustrine sediments.

Preclinical Evaluation of a Protein-Based Nanoscale Contrast Agent for MR Angiography at an Ultralow Dose.

BSA-biomineralized Gd nanoparticles (Gd@BSA NPs) have been recognized as promising nanoscale MR contrast agents. The aim of this study was to carry out a preclinical evaluation of these NPs in a middle-sized animal model (rabbits). New Zealand white rabbits were treated intravenously with Gd@BSA NPs (0.02 mmol Gd/kg) via a clinically-used high-pressure injector, with commercial Gd-diethylene triamine pentaacetate (Gd-DTPA)-injected group as control. Then MR angiography was performed according to the standard clinical protocol with a 3.0-T MR scanner. The SNR and CNR of the main arteries and branches were monitored. Pharmacokinetics and bioclearance were continuously evaluated in blood, urine, and feces. Gd deposition in vital organs was measured by ICP‒MS. Weight monitoring, HE staining, and blood biochemical analysis were also performed to comprehensively estimate systemic toxicity. The ultrasmall Gd@BSA NPs (<6 nm) exhibited high stability and T1 relaxivity. Compared to Gd-DTPA, Gd@BSA NPs demonstrated superior vascular system imaging performance at ultralow doses, especially of the cardiac artery and other main branches, and exhibited a significantly higher SNR and CNR. Notably, the Gd@BSA NPs showed a shorter half-life in blood, less retention in organs, and improved biocompatibility. The preclinical evaluations here demonstrated that Gd@BSA NPs are promising and advantageous MR CA candidates that can be used at a low dose with excellent MR imaging performance, thus suggesting its further clinical trials and applications.