Subcooled liquid nitrogen and nitrogen slush are often considered for high-speed cooling, but their preparation and maintenance are not easy. To address this issue, a unique device was designed to prepare subcooled liquid argon (SLA) using liquid nitrogen (LN). The cooling process was mathematically modeled to predict the preparation time. If the interlayer space between LN and liquid argon is filled with nitrogen gas, liquid argon could be cooled to 3.5 K subcooling within one hour. If the interlayer is filled with air, two hours are required to achieve the same subcooled state. An additional 1000 mL of LN was required for the preparation of 600 mL of 3.5 K SLA. The cooling tests of 3μL microdroplets in 3 mm-6 mm capillary quartz tubes were duplicated to evaluate the potential of SLA. It was found that the cooling rate of microdroplet in the 3.5 K subcooled SLA is very close to that in the 3 K subcooled LN, higher than that in the saturated LN. The convenience of preparation and maintenance of SLA can make it good choice of cryogen for cryopreservation of biomaterials.

We present a method to calculate dielectric and refractivity virial coefficients using the path-integral Monte Carlo formulation of quantum statistical mechanics and validate it by comparing our results with equivalent calculations in the literature and with more traditional quantum calculations based on wavefunctions. We use state-of-the-art pair potentials and polarizabilities to calculate the second dielectric and refractivity virial coefficients of helium (both 3He and 4He), neon (both 20Ne and 22Ne), and argon. Our calculations extend to temperatures as low as 1 K for helium, 4 K for neon, and 50 K for argon. We estimate the contributions to the uncertainty of the calculated dielectric virial coefficients for helium and argon, finding that the uncertainty of the pair polarizability is by far the greatest contribution. Agreement with the limited experimental data available is generally good, but our results have smaller uncertainties, especially for helium. Our approach can be generalized in a straightforward manner to higher-order coefficients.

The primary objective of this study was to investigate the pharmacokinetics of inhaled argon in young pigs using mechanical ventilation. Also a physiologically based model of argon pharmacokinetics (PBPK) is validated with human data for xenon from the literature and the new data from juvenile pigs. The inherent difficulty in performing pharmacokinetics studies of argon makes the use of the PBPK model especially relevant. The model is used to investigate argon pharmacokinetics for adult and neonate applications. Juvenile pigs (n = 4) were anesthetized, submitted to endotracheal intubation, and mechanical ventilation using a conventional ventilator. Argon inhalation was achieved by switching the animal from the first mechanical ventilator (with air/oxygen) to a second one that was supplied with 75% argon and 25% oxygen from premixed gas cylinders. This administration yielded blood samples that were analyzed using a quadrupole based technique for determining argon concentration. The range of blood:gas partition coefficient corresponding to the average measured Cmax of 190-872 μM is 0.005-0.022. Based on the average curve, T1/2= 75 seconds. The PBPK is shown to be in general agreement with the experimental data in pigs. Inhaled argon administration exhibited an on-off nature such that AUC was proportional to administration time. Confidence in the PBPK model and the remarkably robust and stable on-off nature of argon pharmacokinetics, notwithstanding intersubject variability and comorbidity, suggests that inhaled argon could readily be applied to any treatment regime.

A new method of efficiently transforming water vapor into hydrogen was investigated by dielectric barrier discharge (DBD) loaded with bamboo carbon bed structured by fibrous material in an argon medium. Hydrogen productivity was measured in three different reactors: a non-loaded DBD (N-DBD), a bamboo carbon (BC) bed DBD (BC-DBD), and a quartz wool (QW)-loaded BC DBD (QC-DBD). The effects of the quality ratio of BC to QW and relative humidity on hydrogen productivity were also investigated in QC-DBD at various flow rates. The reaction process and mechanism were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy, N2 physisorption experiments, infrared spectroscopy, and optical emission spectroscopy. A new reaction pathway was developed by loading BC into the fibrous structured material to activate the reaction molecules and capture the O-containing groups in the DBD reactor. A hydrogen productivity of 17.3 g/kWh was achieved at an applied voltage of 5 kV, flow rate of 4 L/min, and 100% relative humidity (RH) in the QC-DBD with a quality ratio of BC to QW of 3.0.

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Reactive molecular dynamics (MD) simulations were conducted to investigate the soft and reactive landing of hyperthermal velocity proteins transferred to a vacuum using large argon clusters. Experimentally, the interaction of argon cluster ion beams (Ar1000-5000+) with a target biofilm was previously used in such a manner to transfer lysozymes onto a collector with the retention of their bioactivity, paving the way to a new solvent-free method for complex biosurface nanofabrication. However, the experiments did not give access to a microscopic view of the interactions needed for their full understanding, which can be provided by the MD model. Our reactive force field simulations clarify the landing mechanisms of the lysozymes and their fragments on collectors with different natures (gold- and hydrogen-terminated graphite). The results highlight the conditions of soft and reactive landing on rigid surfaces, the effects of the protein structure, energy, and incidence angle before landing, and the adhesion forces with the collector substrate. Many of the obtained results can be generalized to other soft and reactive landing approaches used for biomolecules such as electrospray ionization and matrix-assisted laser desorption ionization.

The purpose of this study was to evaluate the effect of the atmospheric pressure plasma treatment as a surface treatment method on the contact angle and shear bond strength (SBS) of zirconia ceramics and the failure mode between the self-adhesive resin luting agent and zirconia. The zirconia specimens were divided into eight groups based on the surface treatment method: alumina blasting, air plasma, argon plasma (AP), Katana cleaner, ozonated water, ozonated water+AP, Katana cleaner+AP, and tap water+AP. The contact angles, SBS, and fracture modes were tested. AP treatment significantly reduced the contact angle (p<0.0001). The combination of AP and other cleaning methods showed a higher bond strength and more mixed fractures. Our findings indicate that using atmospheric pressure plasma with argon gas, combined with other cleaning methods, results in a stronger bond than when using alumina blasting alone.

BACKGROUND: Argon gas poisoning is an often overlooked yet critical public health concern with the potential for severe and persistent neurological consequences. Current treatment protocols primarily focus on acute-phase management, but a comprehensive understanding of the long-term neurological effects remains incomplete.
METHODS: A 22-year-old male worker was found unconscious in the furnace room of an argon production facility. After regaining consciousness, he presented with symptoms of dizziness, headache, fatigue, and irritability. Neurological examination revealed impairments in both recent and remote memory, notably pronounced short-term memory deficits and reduced arithmetic skills.
METHODS: Argon gas poisoning, hypoxic encephalopathy, and mild hepatic and renal dysfunction.
METHODS: Upon admission, symptomatic supportive measures included oxygen therapy via nasal cannula (3 L/min), daily hyperbaric oxygen therapy (1.5 ATA, 60 minutes), oral neurotrophic methylcobalamin (0.5 mg, 3 times daily), and intravenous vitamin C infusion (2 g daily) to scavenge oxygen free radicals.
RESULTS: A 2-year telephone follow-up indicated persistent short-term memory impairment, particularly with memorizing numbers. In a memory test, he achieved a digit span forward of 5 but a digit span backward of 2, indicating impairment. Despite these challenges, his daily life and work performance remained largely unaffected.
CONCLUSIONS: This case offers valuable insights into the biological mechanisms underlying prolonged neurological sequelae following asphyxiating gas exposure, specifically the persistent impairment of hippocampal function.

This paper investigates the effects of argon (Ar) and that of Ar mixed with ambient air (Ar-Air) cold plasma jets (CPJs) on 4-nitrophenol (4-NP) degradation using low input power. The introduction of ambient air into the Ar-Air plasma jet enhances ionization-driven processes during high-voltage discharge by utilizing nitrogen and oxygen molecules from ambient air, resulting in increased reactive oxygen and nitrogen species (RONS) production, which synergistically interacts with argon. This substantial generation of RONS establishes Ar-Air plasma jet as an effective method for treating 4-NP contamination in deionized water (DW). Notably, the Ar-Air plasma jet treatment outperforms that of the Ar jet. It achieves a higher degradation rate of 97.2% and a maximum energy efficiency of 57.3 gkW-1h-1, following a 6-min (min) treatment with 100 mgL-1 4-NP in DW. In contrast, Ar jet treatment yielded a lower degradation rate and an energy efficiency of 75.6% and 47.8 gkW-1h-1, respectively, under identical conditions. Furthermore, the first-order rate coefficient for 4-NP degradation was measured at 0.23 min-1 for the Ar plasma jet and significantly higher at 0.56 min-1 for the Ar-Air plasma jet. Reactive oxygen species, such as hydroxyl radical and ozone, along with energy from excited species and plasma-generated electron transfers, are responsible for CPJ-assisted 4-NP breakdown. In summary, this study examines RONS production from Ar and Ar-Air plasma jets, evaluates their 4-NP removal efficacy, and investigates the biocompatibility of 4-NP that has been degraded after plasma treatment.

Carbon material modification and defect engineering are indispensable for bolstering the photocatalytic effectiveness of bismuth halide oxide (BiOX). In this study, a novel porous and defect-rich Ar-CB-2 photocatalyst was synthesized for emerging pollutants degradation. Leveraging the interfacial coupling effect of multi-walled carbon nanotubes (MWCNTs), we expanded the absorption spectrum of BiOI nanosheets and significantly suppressed the recombination of charge carriers. Introducing defects via Argon (Ar) plasma-etching further bolstered the adsorption efficacy and electron transfer properties of photocatalyst. In comparison to the pristine BiOI and CB-2, the Ar-CB-2 photocatalyst demonstrated superior photodegradation efficiency, with the first-order reaction rates for the photodegradation of tetracycline (TC) and bisphenol A (BPA) increasing by 2.83 and 4.53 times, respectively. Further probe experiments revealed that the steady-state concentrations of ·O2- and 1O2 in the Ar-CB-2/light system were enhanced by a factor of 1.67 and 1.28 compared to CB-2/light system. This result confirmed that the porous and defect-rich structure of Ar-CB-2 inhibited electron-hole recombination and boosted photocatalyst-oxygen interaction, swiftly transforming O2 into active oxygen species, thus accelerating their production. Furthermore, the possible degradation pathways for TC and BPA in the Ar-CB-2/light system were predicted. Overall, these findings offered a groundbreaking approach to the development of highly effective photocatalysts, capable of swiftly breaking down emerging pollutants.