Low Density Research Articles

Dynamic evolution of tidal networks under the combined effect of de-reclamation and decrease of sediment supply

De-reclamation is a common strategy used for the restoration of tidal flats. In this study, we investigate the morphodynamic response of tidal channel networks and tidal flats after de-reclamation initiatives using the Delft3D numerical model. We find that tidal channel networks that have undergone reclamation and retreat projects have a lower drainage density (8.95 km−1) than that of channel networks that formed naturally (11.33 km−1), and the drainage efficiency of natural formed channel networks is almost three times greater than restored channel networks. These findings indicate that de-reclamation alone cannot fully erase the imprinting of the previous reclamation. We also find that the ultimate effectiveness of de-reclamation is affected by the geographical layout and unchanneled path length of the inchoate main creek system. In addition, following the implementation of de-reclamation, the immediate opening of previously enclosed areas amplifies the tidal prism, thereby intensifying tidal scouring and resulting in significant erosion, with erosion rate reaching hundreds of millimeters per day. Such losses can be remediated under sufficient sediment supply and prevented through the construction of artificial channels. However, this severe erosion may escalate under an insufficient sediment supply or a heightened tidal prism, potentially leading to permanent loss. These findings constitute an important reference for future engineering practices that support the safety and sustainability of coastal resources.

Effect of heat treatment on wear and corrosion behaviour of ZE41 magnesium alloy

ABSTRACT In the present study, T5 heat treatment was performed on ZE41 magnesium alloy, and the effect of altered microstructure on wear, friction and corrosion behaviour was evaluated. After the heat treatment, smaller grain size (91 ± 10 µm) was measured compared with the base alloy (110 ± 12 µm). Increased tensile strength from 156.4 ± 9.4 to 172.8 ± 8.9 MPa was achieved after the heat treatment. Owing to smaller grains and formation of precipitates, heat-treated alloy exhibited better wear resistance compared to as-cast alloy, and a 22% reduction in the wear rate was observed. Abrasion, oxidation and delamination were observed as the dominant wear mechanisms. The enhanced corrosion resistance of heat-treated alloy as reflected with lower corrosion current density (7.29 ± 1.25 µA cm–2) compared with base alloy (18.87 ± 2.13 µA cm–2) is attributed to the microstructural modification and the presence of zinc- and zirconium-rich regions at the centre of the grains. Furthermore, the corroded surface morphology indicates localised intergranular and micro-galvanic corrosion. The corrosion rate was reduced by 2.6 times after the heat treatment. The results demonstrate the improved tribocorrosion behaviour of heat-treated ZE41 alloy suitable for light weight structural applications.

The great escape: understanding the connection between Ly α emission and LyC escape in simulated JWST analogues

ABSTRACT Constraining the escape fraction of Lyman Continuum (LyC) photons from high-redshift galaxies is crucial to understanding reionization. Recent observations have demonstrated that various characteristics of the Ly$\, \alpha$ emission line correlate with the inferred LyC escape fraction ($f_{\rm esc}^{\rm LyC}$) of low-redshift galaxies. Using a data set of 9600 mock Ly$\, \alpha$ spectra of star-forming galaxies at $4.64 \le z \le 6$ from the SPHINX$^{20}$ cosmological radiation hydrodynamical simulation, we study the physics controlling the escape of Ly$\, \alpha$ and LyC photons. We find that our mock Ly$\, \alpha$ observations are representative of high-redshift observations and that typical observational methods tend to overpredict the Ly$\, \alpha$ escape fraction ($f_{\rm esc}^{\rm Ly\, \alpha }$) by as much as 2 dex. We investigate the correlations between $f_{\rm esc}^{\rm LyC}$ and $f_{\rm esc}^{\rm Ly\, \alpha }$, Ly$\, \alpha$ equivalent width ($W_{\lambda }({\rm Ly\, \alpha })$), peak separation ($v_{\rm sep}$), central escape fraction ($f_{\rm cen}$), and red peak asymmetry ($A_f^{\rm red}$). We find that $f_{\rm esc}^{\rm Ly\, \alpha }$ and $f_{\rm cen}$ are good diagnostics for LyC leakage, selecting for galaxies with lower neutral gas densities and less UV attenuation that have recently experienced supernova feedback. In contrast, $W_{\lambda }({\rm Ly\, \alpha })$ and $v_{\rm sep}$ are found to be necessary but insufficient diagnostics, while $A_f^{\rm red}$ carries little information. Finally, we use stacks of Ly$\, \alpha$, H$\, \alpha$, and F150W mock surface brightness profiles to find that galaxies with high $f_{\rm esc}^{\rm LyC}$ tend to have less extended Ly$\, \alpha$ and F150W haloes but larger H$\, \alpha$ haloes than their non-leaking counterparts. This confirms that Ly$\, \alpha$ spectral profiles and surface brightness morphology can be used to better understand the escape of LyC photons from galaxies during the epoch of reionization.

Lipid nanoparticle-mediated hepatocyte delivery of siRNA and silibinin in metabolic dysfunction-associated steatotic liver disease

Lipid nanoparticle-mediated co-delivery of siRNA and small molecule holds a great potential to treat metabolic dysfunction-associated steatotic liver disease (MASLD). However, targeted delivery of therapeutics to hepatocytes remains challenging. Taking the advantage of rising low density lipoprotein receptor/very-low density lipoprotein receptor (LDLR/VLDR) levels in MASLD, the biological fate of dinonylamine-ethylene glycol chlorophosphate-1-nonanol (DNNA-COP-NA) based lipid nanoparticles (LNPs) was oriented to liver tissues via apolipoprotein E (ApoE)-LDLR/VLDLR pathway. We then adopted a three-round screening strategy to optimize the formulation with both high potency and selectivity to deliver siRNA-HIF-1α (siHIF1α) and silibinin (SLB) payloads to hepatocytes. The optimized SLB/siHIF1α-LNPs mediates great siRNA delivery and transfection of hepatocytes. In high fat diet (HFD)- and carbon tetrachloride (CCl4)-induced mouse models of MASLD, SLB/siHIF1α-LNPs enabled the silencing of hypoxia inducible factor-1α (HIF-1α), a therapeutic target primarily expressed by hepatocytes, leading to significantly reduced inflammation and liver fibrosis synergized with SLB. Moreover, it is demonstrated the hepatocyte-targeting delivery of SLB/siHIF1α-LNPs has the potential to restore the immune homeostasis by modulating the population of Tregs and cytotoxic T cells in spleen. This proof-of-concept study enable siRNA and small molecule co-delivery to hepatocytes through intrinsic variation of targeting receptors for MASLD therapy.

Predicting hardness of graphene-added Si3N4 using machine learning: A data-driven approach

This study presents a data-driven framework based on machine learning (ML) using extreme gradient boosting (XGBoost) for predicting the hardness of silicon nitride (Si3N4) ceramics reinforced with graphene. The XGBoost model takes into account various factors such as graphene type and content, characteristics of the raw Si3N4 powder, the parameters of the sintering process (sintering technique, temperature, pressure, holding time), and the characteristics of the sintered samples, i.e., the density, αβ content and Vickers hardness. The parameters that influence the Si3N4 hardness most strongly are identified, with sintering pressure, sintering time and density being the most influential. The addition of graphene content up to a certain threshold (1 wt%) has a positive impact on hardness. However, beyond that it leads to a lower density and a lower mechanical performance. Sintering parameters, particularly the sintering pressure, temperature, holding time and technique, strongly affect the density, final grain size, αβ Si3N4 composition and subsequently the hardness. The study highlights the importance of density and the densification process in achieving high hardness in Si3N4 ceramics. The developed ML model provides a valuable tool for predicting the hardness of Si3N4+graphene ceramics composites and offers insights into selecting suitable graphene type, content, and processing parameters. While the study primarily focuses on Si3N4+graphene composites, this novel approach holds promise for the in-silico design and analysis of diverse ceramic materials.

A comparative approach for life history and functional response demonstrates similar survival strategies for Trichogramma evanescens and T. pintoi.

Egg parasitoids are important biological control agents of lepidopteran pests of agricultural crops. Trichogramma evanescens Westwood and T. pintoi Voegele (Hymenoptera: Trichogrammatidae) are egg parasitoids with worldwide importance. The parasitoid selection necessitates comparative assessment of the life table traits and functional response analysis to provide insights into their effectiveness in pest control. In this study, we examined theirlife table traits including survivorship and reproductivity, and functional response and associated parameters i.e., attack coefficient and handling time. Life table parameters, using age-stage, two-sex theory, revealed similar survival and reproductive strategies for both species. For example, the female longevity, oviposition days and fecundity did not differ between both species. Exceptionally, the male longevity of T. evanescens was shorter than that of T. pintoi. The population growth parameters such as gross reproductive rate (GRR), net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and mean generation time (T) did not differ between species. The polynomial logistic regression yielded a type III functional response and a non-linear least square analysis revealed different attack coefficient and similar handling time. However, their parasitism rate differed between the lowest (five eggs) and highest (80 eggs) initial host egg densities such that T. evanescens had a lower parasitism rate at the lowest density and higher parasitism rate at the highest density. The similarity in survival strategies and minor differences in host handling of both parasitoids are discussed in terms of relevance to applied biological control applications and evolutionary traits. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Mechanical properties and energy absorption of medium-entropy alloy triply periodic minimal surface cellular structures fabricated via selective laser melting

Triply periodic minimal surfaces (TPMSs) are extensively used as effective tools for the microarchitectural designing of cellular structures. CoCrNi medium-entropy alloy, known for its high strength and high ductility, is an ideal candidate for fabricating TPMS-based structures. However, few studies have focused on this topic. This study investigated the compressive mechanical and energy absorption properties of CoCrNi D-sheet TPMS cellular structures fabricated via selective laser melting (SLM). The surface morphology of the fabricated D-sheet TPMS structure was observed through scanning electron microscopy, and the deformation and failure mechanisms of the structure were analyzed by the quasi-static compression test. The results indicated that the SLM-ed CoCrNi D-sheet TPMS structure exhibited stable collapse mechanisms compared to other metal-based TPMS structures. Meanwhile, the energy absorption characteristics of the modified finite element (FE) model agreed well with the experimental results. Furthermore, the impact of the level constant on the energy absorption performance of the D-sheet TPMS structure was investigated using the FE model. Thus, an optimal D-sheet (OD-sheet) TPMS structure with lower density and higher energy absorption capacity was obtained. Additionally, the Gibson–Ashby prediction model was established to aid in selecting CoCrNi OD-sheet TPMS structures with controlled relative densities for energy absorption applications.

Optical and thermodynamic investigation of jet-guided spark ignited hydrogen combustion

Hydrogen as an alternative fuel for engines is gaining interest to decarbonize the heavy-duty sector. Hydrogen combustion in engines conventionally relies on the Otto cycle and either port fuel or direct injection. This combustion concept usually results in poor power density and non-ideal efficiencies due to the lean premixed operation and low compression ratio required to avoid preignition and knocking. In this study, hydrogen is directly injected at high pressures into the combustion chamber and spark-ignited with two different ignition systems (inductive and nanosecond repetitively pulsed discharge) at the periphery of the jet, with fuel conversion taking place predominantly in jet-guided (diffusion) mode while injection remains active.A rapid compression expansion machine (RCEM) is used to investigate the jet-guided hydrogen combustion thermodynamically and optically by combining high-speed Schlieren and OH* chemiluminescence imaging, and spark-induced breakdown spectroscopy (SIBS).SIBS reveals low air to fuel ratios at ignition time and location, ranging from 2.8 up to pure air depending on the condition and significant variation among repetitions. Both OH* chemiluminescence and Schlieren images illustrate how air entrainment pushes the flame-plasma kernel from the ignition location at the periphery of the jet towards the fuel-richer core, resulting in fast combustion of the already premixed fuel. Subsequently, the combustion process becomes dominated by the mixing dynamics. Under conditions of low in-cylinder pressures, the Heat Release Rate (HRR) closely follows the injected mass flow rate multiplied by the lower heating value of hydrogen, i.e., the combustion is mixing controlled. However, as the cylinder pressure increases, the mixing and combustion rates fall below the injected mass flow until lower densities are reached again.The delay between the start of injection and ignition primarily impacts the premixed peak, but the in-cylinder pressure and ignition source also play significant roles. This distinctive combustion process shows essential similarities to compression ignition Diesel combustion. The process holds the potential to achieve high efficiency, as hydrogen can be burned using process parameters typical of Diesel combustion without facing the constraints of knock or preignition and a complete absence of soot.

Bone mineral density assessment in patients with cystinuria.

Cystinuria is a rare genetic disease characterized by impaired tubular transport of cystine. Clinical features of cystinuria mainlyinclude nephrolithiasis and its complications, although cystinuric patients may present with other comorbidities. There are currently no data on bone features of patients with cystinuria. Our aim is to characterize bone mineral density (BMD) in cystinuria. Our study included adult cystinuric patients with estimated glomerular filtration rate (eGFR) ≥ 60mL/min/1.73m2 followed at 3 specialized outpatient clinics in Italy (Rome, Naples and Verona). Markers of bone turnover were analyzed in a centralized laboratory. Clinical, biochemical and dual-energy X-ray absorptiometry (DEXA) data were collected from September 2021 to December 2022. Linear regression models were used to evaluate statistically significant deviations from zero of Z-scores. Twenty-seven patients were included in the study. Mean (SD) age was 37 (15) years, 41% were women. Mean estimated glomerular filtration rate was 99mL/min/1.73m2. Serum parameters associated with bone turnover (parathyroid hormone, FGF23, calcium and phosphate) were all in the normal range, with only 4 patients showing mild hypophosphatemia. Prevalence of low bone mineral density, defined as Z-score ≤ - 2 at any site, was 15%. Average Z-scores were negative across most sites. Our study suggests that cystinuric patients have lower bone mineral density compared with individuals of the same sex and age, even when theirkidney functionis normal.

The Use of Content-Marketing in Complex Development of Non-Urbanized Territories in Russia

The article deals with practical aspects of using content-marketing to improve social and economic appeal and complex development of non-urbanized territories in Russia. The author showed that the process of business climate development on territories with low population density is a whole complex of measures. In practice they are connected with target positioning of each region and spot lighting of its concrete benefits for potential partners and economically active people, who would like to swap their megalopolis for more placid life and realize themselves beyond big cities. It was shown that content-marketing can serve as a universal tool for resolving problems of regional development in Russia. It is based on approaches of step-by-step bringing the target audience to decisionmaking about buying goods, services or taking part in an investment project. In case of Russian regions it means a decision to invest in the region, set up highly-technological enterprises or business connected with agriculture. At the same time entrepreneurs could get an additional incentive for realizing their ideas in the form of state support with a broad range of tax privileges and subsidies and as maximum – availability of a preferential zone in the region, where state is interested in creating jobs and intensive development of a concrete territory. It was underlined that in Russia preferential zones are mainly arranged on non-urbanized territories far from big cities and agglomerations. The article provided examples of content-marketing functioning in promotion of existing highlytechnological enterprises and business-projects being developed now in every region of the country. The use of successful experience in developing regions was studied also on less successful territories, which require operative alterations in their positioning. A conclusion was drawn that high-quality positioning of the region is a secure investment in its development and a universal tool for sustainable development of non-urbanized territories in Russia.

Low Current Density Cathode Plasma Electrolytic Deposition of Aluminum Alloy Based on a Bipolar Pulse Power Supply

Low Current Density Cathode Plasma Electrolytic Deposition of Aluminum Alloy Based on a Bipolar Pulse Power Supply

Highly Anion-Conductive Viologen-based Two-Dimensional Polymer Membranes as Nanopower Generators.

Two-dimensional polymers (2DPs) and their layer-stacked 2D covalent organic frameworks (2D COFs) membranes hold great potential for harvesting sustainable osmotic energy. The nascent research has yet to simultaneously achieve high ionic flux and selectivity, primarily due to inefficient ion transport dynamics. This is directly related to ultrasmall pore size (<3 nm), much smaller than the duple Debye length in the diluted electrolyte (6~20 nm), as well as low charge density (<4.5 mC m-2). Here, we introduce a π-conjugated viologen-based 2DP (V2DP) membrane possessing a large pore size of 4.5 nm, strategically enhancing the overlapping of the electric double layer, coupled with an exceptional positive surface charge density (~6 mC m-2). These characteristics enable the membrane to facilitate high anion flux while maintaining ideal selectivity. Notably, V2DP membranes realize an impressive current density of 5.5×103 A m-2, surpassing previouslynanofluidic membranes. Inpractical application scenario involving the mixing of artificial seawater and river water, the V2DP membranes exhibit a considerable ion transference number of 0.70 towards Cl-, contributing to an outstanding power density of ~55 W m-2. Theoretical calculations reveal that thelarge quantity of anion transport sites act as binding sites evenly located in the positively charged N-containing pyridine rings.

Demystifying ionic and electronic transport in prominent oxide ion and proton conducting ceramic electrolytes: Ce0.8Sm0.2O2 and BaCe0.7Zr0.1Y0.1Yb0.1O3-δ

ABSTRACT The development and performance of ceramic electrochemical cells (CECs) depend critically on choosing ceramic electrolytes with optimal ionic and electronic transport properties. In this study, we compare the structural, morphological, and transport characteristics of two representative ceramic electrolytes, oxide ion conducting Ce0.8Sm0.2O2 (SDC) and proton conducting BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZYYb). We demonstrate that SDC exhibits higher bulk conductivity but lower open-circuit voltage due to its higher electron density and larger crystallite size. In contrast, BCZYYb possesses higher proton conduction, lower activation energy (0.35–0.38 eV), and higher open-circuit voltage due to its lower electron density and smaller crystallite size with more grain boundaries. BCZYYb shows enhanced proton conductivity in humidified atmospheres due to the hydration of oxygen vacancies, making it more suitable for low-temperature CEC applications. These insights into ceramic electrolyte conduction mechanisms and microstructure-property relationships can guide the optimization of CECs for energy applications.

Development of portable gas sensing system for measuring gas emission concentration and diffusivity using commercial manometric sensors in gas exposed polymers: Application to pure gases, H2, He, N2, O2 and Ar

Low-cost gas sensing system to measure the emission concentration and diffusion coefficient of the gas emitted from specimens, which were exposed by gas under high pressure, was developed using the commercial manometric sensors. The gas emitted from two polymer specimens [low density polyethylene (LDPE) and nitrile butadiene rubber (NBR)] during desorption produced a measurable increase in pressure; this pressure was recorded by a portable data logger in the specimen container chamber. Thus, the molar concentration and diffusivity of the released gas were calculated via the ideal gas equation and diffusion analysis program. As results, gas sensor immediately responded without any chemical interaction and emitted gas weight per specimen weight up to 1400×10−6 with a controllable sensitivity/resolution. The performance test confirmed that our developed sensing technique had good reliability, adjustable measurable range and independence to fluctuations in temperature and pressure. Consequently, the developed simple sensing system was successfully used for the simultaneous real-time detection and transport characterizations for pure gases (H2, He, N2, O2 and Ar).

Association between Deltoid Muscle Density and Proximal Humeral Fracture in Elderly Patients.

The potential role of deltoid muscle density in the occurrence of proximal humeral fractures remains uncertain. Therefore, the primary objective of this study was to examine the correlation between deltoid muscle density, as measured by CT attenuation value in Hounsfield units (HU), and the incidence of proximal humeral fractures in elderly patients. By investigating this association, we aim to shed light on the possible influence of deltoid muscle density on fracture risk in this specific population. A total of 68 patients with computed tomography (CT) images were retrospectively reviewed. Among them, 34 patients presented with fractures following low-energy injuries, while the remaining 34 patients served as controls and underwent CT scans after low-energy injuries without any fractures. The muscle density of the deltoid muscles was assessed at the approximate tubercle of humerus. We compared these parameters between the two groups and conducted analyses considering factors such as age, sex, laterality, and deltoid muscle density of the shoulders. The demographic factors related to the shoulder did not exhibit any significant association with proximal humeral fracture. However, we observed a noteworthy difference in deltoid muscle density between patients with fractures (40.85 ± 1.35) and the control group (47.08 ± 1.61) (p = 0.0042), indicating a lower muscle density in the fracture group. Based on the findings of this study, we can conclude that there exists a negative correlation between deltoid muscle density and the incidence of proximal humeral fractures. These results suggest that lower deltoid muscle density may be associated with an increased risk of proximal humeral fractures in the elderly population under investigation.

Influence of Grain Size and Film Formation Potential on the Diffusivity of Point Defects in the Passive Film of Pure Aluminum in NaCl Solution

The influence of grain size on the corrosion behavior of pure aluminum and the defect density and diffusion coefficient of surface passive films were investigated using electron backscatter diffraction (EBSD) and electrochemical testing techniques, based on the point defect model (PDM). Samples with three different grain sizes (23 ± 11, 134 ± 52, and 462 ± 203 μm) were obtained by annealing at different temperatures and times. The polarization curves and electrochemical impedance spectroscopy results for the pure aluminum in the 3.5% NaCl solution showed that with decreasing grain size, the corrosion current (icorr) decreased monotonously, giving rise to a noble corrosion potential and a large polarization resistance. The Motte–Schottky results showed that the passive films that formed on pure aluminum with fine grains of 23 ± 11 μm had a low density (3.82 × 1020 cm−3) of point defects, such as oxygen vacancies and/or metal interstitials, and a small diffusion coefficient (1.94 × 10−17 cm2/s). The influence of grain size on corrosion resistance was discussed. This work demonstrated that grain refinement could be an effective approach to achieving high corrosion resistance of passive metals.

Application of mesoporous silica particles as an additive for controlling rheological, thermal, and filtration properties of water-based fluids

Mesoporous silica particles (MSP) have received increasing interest for various applications because of their unique features such as controlled pore size, low density, high chemical and thermal stability, and high surface area. In this study, MSP was applied as an additive in water-based drilling fluids (WBMs). The effect of MSP on the rheological, thermal, filtration, and structural properties of WBMs was investigated. The results were compared with those of analogous fluids containing conventional nonporous silica particles (SSP). Rheological assays showed shear-thinning and viscoelastic behavior, which were more noticeable for fluids including MSP. It was observed that low concentrations of MSP (0.25 %wt) can achieve the same rheological properties as the fluids with higher SSP content (up to 0.5 %wt). The rheological properties of SSP-containing fluids were not significantly affected by the presence of NaCl or aging tests. The theoretical Herschel–Bulkley model represents the rheological behavior of WBMs. The MSP-based WBMs exhibited better filtration properties before aging. The microstructures of the WBMs were analyzed using Scanning Electron Microscopy (SEM). A homogeneous distribution of SSP in the WBMs was observed, while particle agglomeration was observed in WBMs containing MSP. In addition, surface interactions were studied to elucidate the interactions between particles and fluid constituents. The surface interaction, assessed through ζ-potential and FTIR analysis, revealed that the binding affinities of BT, PAC, and XGD with MSP were augmented compared to their individual values. Based on the experimental results, MSP constitutes a promising alternative as an additive for the design of WBMs.

Imaging tunable Luttinger liquid systems in van der Waals heterostructures.

One-dimensional (1D) interacting electrons are often described as a Luttinger liquid1-4 having properties that are intrinsically different from those of Fermi liquids in higher dimensions5,6. In materials systems, 1D electrons exhibit exotic quantum phenomena that can be tuned by both intra- and inter-1D-chain electronic interactions, but their experimental characterization can be challenging. Here we demonstrate that layer-stacking domain walls (DWs) in van der Waals heterostructures form a broadly tunable Luttinger liquid system, including both isolated and coupled arrays. We have imaged the evolution of DW Luttinger liquids under different interaction regimes tuned by electron density using scanning tunnelling microscopy. Single DWs at low carrier density are highly susceptible to Wigner crystallization consistent with a spin-incoherent Luttinger liquid, whereas at intermediate densities dimerized Wigner crystals form because of an enhanced magneto-elastic coupling. Periodic arrays of DWs exhibit an interplay between intra- and inter-chain interactions that gives rise to new quantum phases. At low electron densities, inter-chain interactions are dominant and induce a 2D electron crystal composed of phased-locked 1D Wigner crystal in a staggered configuration. Increased electron density causes intra-chain fluctuation potentials to dominate, leading to an electronic smectic liquid crystal phase in which electrons are ordered with algebraical correlation decay along the chain direction but disordered between chains. Our work shows that layer-stacking DWs in 2D heterostructures provides opportunities to explore Luttinger liquid physics.

Amorphous FeSnOx Nanosheets with Hierarchical Vacancies for Room-Temperature Sodium-Sulfur Batteries.

Room-temperature sodium-sulfur (RT Na-S) batteries, noted for their low material costs and high energy density, are emerging as a promising alternative to lithium-ion batteries (LIBs) in various applications including power grids and standalone renewable energy systems. These batteries are commonly assembled with glass fiber membranes, which face significant challenges like the dissolution of polysulfides, sluggish sulfur conversion kinetics, and the growth of Na dendrites. Here, we develop an amorphous two-dimensional (2D) iron tin oxide (A-FeSnOx) nanosheet with hierarchical vacancies, including abundant oxygen vacancies (Ovs) and nano-sized perforations, that can be assembled into a multifunctional layer overlaying commercial separators for RT Na-S batteries. The Ovs offer strong adsorption and abundant catalytic sites for polysulfides, while the defect concentration is finely tuned to elucidate the polysulfides conversion mechanisms. The nano-sized perforations aid in regulating Na ions transport, resulting in uniform Na deposition. Moreover, the strategic addition of trace amounts of Ti3C2 (MXene) forms an amorphous/crystalline (A/C) interface that significantly improves the mechanical properties of the separator and suppresses dendrite growth. As a result, the task-specific layer achieves ultra-light (~0.1 mg cm-2), ultra-thin (~200 nm), and ultra-robust (modulus=4.9 GPa) characteristics. Consequently, the RT Na-S battery maintained a high capacity of 610.3 mAh g-1 and an average Coulombic efficiency of 99.9 % after 400 cycles at 0.5 C.

O-212 A need to standardize: the use and posterior recall of toxic consumables could be avoided with the appropriate testing protocols

Abstract Study question Could the recall of toxic products have been avoided if the samples had been tested with a more sensitive Mouse Embryo Assay (MEA)? Summary answer Standardizing MEA protocols with sensitive methodologies could prevent the potential harm imparted on human embryos and avoid the need to recall initially unidentified toxic products. What is known already Dozens of consumables are used during an IVF cycle, with a potential effect on gametes/embryos in culture. Bioassays, such as the MEA, are commonly used to pinpoint embryo-toxic products/batches before their release. No strict regulations exist on how to perform these tests, although several variables have been described to play a major role on the assay’s sensitivity and its capacity to detect embryo-toxicity. Toxic products/batches that are not identified may need to be recalled. However, recalls are typically issued after the products/batches are suspected of hindering embryo development in clinical laboratories, with the loss of irreplaceable biological samples. Study design, size, duration Only in 2023, four important batch recalls have been issued by regulatory bodies or manufacturers, concerning such diverse products as oil, media, capillaries, or follicle aspiration needles (FAN). Reportedly, thousands of couples undergoing IVF cycles may have been affected by this undetected toxicity in samples that were already MEA-tested by the manufacturers or external testing laboratories, following an undisclosed methodology. Eight of these lots (2xmedia, 3xcapillaries, 2xFAN) were retested with a standardized sensitive MEA protocol. Participants/materials, setting, methods The samples were retested following a high-sensitivity and previously published protocol, using 1-cell stage embryos from a sensitive hybrid mouse strain (B6CBAF1), supplementing with 5mg/ml HSA, and maintaining a low embryo density per droplet. A total of 462 embryos were cultured, allocated to the different test groups (21 + 42 embryos for Medium 1 and 2; 63 + 84+147 embryos for Capillaries 1, 2 and 3; 42 + 42 embryos for FANs 1 and 2, respectively). Main results and the role of chance Embryos were cultured at 37.3oC, 6%CO2 and 7%O2 for 5 days (96h). The expanded blastocyst formation rate (BFR) in each group was assessed as the end-point of the assays, and an 80% was considered as the toxicity-marking threshold. When cultured in Medium 1 and Medium 2, supplemented with 5mg/ml HSA, only 0/21 (0%) and 7/63 (11.1%) of embryos reached the expanded blastocyst stage, respectively. Capillaries and FANs were tested with an indirect method, in which the samples were first incubated with a small volume of control culture medium, and the extract was used to culture the embryos. With this approach, Capillaries 1, 2 and 3 yielded a 23.8% (15/63), 22.6% (19/84) and 0.7% (1/147) BFR, respectively. Similarly, when testing FANs 1 and 2, only 66.7% (28/42) and 19.1% (8/42) of the embryos were able to form a blastocyst. Unfortunately, the recalled oil batches were not available for retest. In parallel to each test, a control group was cultured with standard culture medium without contact with any of the samples; the BFR in all control groups was above 80%. These surprisingly low results suggest that toxicity was present in these samples in high concentrations, evidencing the need for their recall. Limitations, reasons for caution The methodology used in this project successfully identified all the recalled samples as embryo-toxic. However, the same protocol might not prove equally sensitive when testing other products, as the sensitivity of the MEA has been shown to be highly dependent on numerous external factors and to vary between different toxins. Wider implications of the findings Recent events could lead to the belief that the MEA is an insensitive bioassay to assess embryo-toxicity. Far from true, attention should be paid to the specific methodology used in each case. The lack of regulations and standardization translates into huge differences in sensitivity, even leading to completely contrary results. Trial registration number not applicable