Search Results (5)

The increasing use of Technology-Critical Elements (TCEs) in modern technology has led to widespread environmental release, raising questions about their biological effects, as emerging evidence suggests significant toxicity. We investigated the effects of three technology-critical elements, Indium oxide (In₂O₃), Lanthanum nitrate hexahydrate (La(NO₃)₃·6H₂O) and Cerium(III) nitrate hexahydrate (Ce(NO₃)₃·6H₂O), on human dermal fibroblasts (BJ) and hepatocarcinoma cells (HepG2), assessing their uptake, impact on viability, and induced cellular stress responses, quantified by markers of inflammation, oxidative stress, and membrane damage. Our results show a strong differential susceptibility: normal BJ fibroblasts proved vulnerable, whereas HepG2 cells were highly resistant. This divergence occurred despite substantial and comparable accumulation of all three TCEs in both cell lines, indicating that toxicity is uncoupled from the magnitude of the uptake. Mechanistically, the differential toxicity correlated strongly with opposing antioxidant responses. Additionally, low concentrations of cerium (III) nitrate (12.5–50 µg/mL) uniquely stimulated the proliferation of HepG2 cells (up to 129% of control). While these findings identify multiple mechanistic hazards regarding the potential of low-level technology-critical element exposure, they must be interpreted cautiously and warrant further investigation in more complex biological models. Full article

The National Institute of Standards and Technology (NIST) is developing analytical methods to characterize extracellular vesicles (EVs) to support the urgent need for standardized EV reference materials (RMs). This study used orthogonal techniques, cryogenic electron microscopy (Cryo-EM), particle tracking analysis (PTA), asymmetrical flow field-flow fractionation (AF⁴), and microfluidic resistive pulse sensing (MRPS), to evaluate particle size distributions (PSDs) and particle number concentrations (PNCs) of human mesenchymal stem cells (MSCs) and LNCaP prostate cancer cell EVs. Proteomic profiles were assessed by mass spectrometry (MS), and microRNA (miRNA) content of LNCaP EVs was evaluated by small RNA-seq at two independent laboratories. A commercial green fluorescent protein exosome served as a control, except in Cryo-EM, proteomic, and miRNA analyses. Cryo-EM, regarded as the gold standard for morphological resolution, served as PSD reference. PSDs from all methods skewed larger than Cryo-EM, with MRPS closest, AF⁴ most divergent, and PTA intermediate with broader distributions. All techniques reported broad PSDs (30 nm to >350 nm) with PNCs decreasing with increasing particle size, except for AF⁴. Quantitative discrepancies in PNCs reached up to two orders of magnitude across methods and cell sources. MS identified global and EV-specific proteins, including syntenin-1 and tetraspanins CD9, CD63, and CD81. RNA-seq revealed notable inter-laboratory variation. These findings highlight the variability across measurement platforms and emphasize the need for reproducible methods to support NIST’s mission of developing reliable EV reference materials. Full article

Low-permeability sandstone reservoirs have low permeability, but due to their high porosity and difficulty in development, the development difficulty is relatively high. They can fully tap into the high potential of oil and gas resources in low-permeability sandstone reservoirs and occupy an important position in the global energy supply The study area belongs to low-permeability dense sandstone reservoir, and the destination layer has complex lithology, strong physical inhomogeneity, and complicated pore–permeability relationship, so the conventional core pore–permeability regression method and NMR SDR method do not satisfy the requirements of fine evaluation in terms of the accuracy of permeability calculation. According to the principle of resistivity measurement by electromagnetic waves with Logging While Drilling (LWD), this paper analyzes the reasons for the magnitude of resistivity divergence with Logging While Drilling at different exploration depths. There is a “low invasion phenomenon” during the drilling process of the drill bit. The higher the permeability of the formation, the more severe the “low invasion phenomenon”, and the greater the magnitude of resistivity divergence. In this paper, through the conventional log curve response characteristics and correlation analysis, the P40H/P16H parameter were selected to characterize the magnitude of resistivity divergence, and a fine evaluation model of the reservoir based on the P40H/P16H parameter was established in the study area by relying on the theory of the flow unit, and was applied to the prediction of permeability of new wells. The application results show that the calculated permeability is in good agreement with the results of core analysis, which provides a theoretical basis for the fine evaluation of low-permeability tight reservoirs. Full article

We discuss the effect of topological inhomogeneity of very thin metallic conductometric sensors on their response to external stimuli, such as pressure, intercalation, or gas absorption, that modify the material’s bulk conductivity. The classical percolation model was extended to the case in which several independent scattering mechanisms contribute to resistivity. The magnitude of each scattering term was predicted to grow with the total resistivity and diverge at the percolation threshold. We tested the model experimentally using thin films of hydrogenated palladium and CoPd alloys where absorbed hydrogen atoms occupying the interstitial lattice sites enhance the electron scattering. The hydrogen scattering resistivity was found to grow linearly with the total resistivity in the fractal topology range in agreement with the model. Enhancement of the absolute magnitude of the resistivity response in the fractal range thin film sensors can be particularly useful when the respective bulk material response is too small for reliable detection. Full article

A half-critical weight-average molecular weight ( ${\overline{M}}_{\mathrm{w}}$ ) (approximately 21,000 g mol⁻¹), high-ion-content Zn-salt poly(styrene–ran–cinnamic-acid) (SCA–Zn) ionomer was successfully synthesized by styrene–cinnamic-acid (10.8 mol %) copolymerization followed by excess-ZnO melt neutralization. At 220 °C, the SCA–Zn’s viscosity was only approximately 1.5 magnitude orders higher than that of commercial polystyrene (PS) at 10² s⁻¹, and the PS/SCA–Zn (5–40 wt %) melt blends showed apparently fine, two-phased morphologies with blurred interfaces, of which the 95/5 and 90/10 demonstrated Han plots suggesting their near miscibility. These indicate that any PS–(SCA–Zn) processability mismatch was minimized by the SCA–Zn’s half-critical ${\overline{M}}_{\mathrm{w}}$ despite its dense ionic cross-links. Meanwhile, the SCA–Zn’s Vicat softening temperature (VST) was maximized by its cross-linking toward 153.1 °C, from that (97.7 °C) of PS, based on its half-critical ${\overline{M}}_{\mathrm{w}}$ at which the ultimate glass-transition temperature was approximated. Below approximately 110 °C, the PS/SCA–Zn (0–20 wt %) were seemingly miscible when their VST increased linearly yet slightly with the SCA–Zn fraction due to the dissolution of the SCA–Zn’s cross-links. Nevertheless, the 60/40 blend’s VST significantly diverged positively from the linearity until 111.1 °C, revealing its phase-separated morphology that effectively enhanced the heat resistance by the highly cross-linked SCA–Zn. This work proposes a methodology of improving PS heat resistance by melt blending with its half-critical ${\overline{M}}_{\mathrm{w}}$ , high-ion-content ionomer. Full article