Search Results (31)

Hydrogen and some of its derivatives (such as e-methanol, e-methane, and e-ammonia) are promising energy carriers that have the potential to replace conventional fuels, thereby eliminating their harmful environmental impacts. An innovative use of hydrogen as a zero-emission fuel is forming weakly ionized plasma by seeding the combustion products of hydrogen with a small amount of an alkali metal vapor (cesium or potassium). This formed plasma can be used as a working fluid in supersonic open-cycle magnetohydrodynamic (OCMHD) power generators. In these OCMHD generators, direct-current (DC) electricity is generated straightforwardly without rotary turbogenerators. In the current study, we quantitatively and qualitatively explore the levels of electric conductivity and the resultant volumetric electric output power density in a typical OCMHD supersonic channel, where thermal equilibrium plasma is accelerated at a Mach number of two (Mach 2) while being subject to a strong applied magnetic field (applied magnetic-field flux density) of five teslas (5 T), and a temperature of 2300 K (2026.85 °C). We varied the total pressure of the pre-ionization seeded gas mixture between 1/16 atm and 16 atm. We also varied the seed level between 0.0625% and 16% (pre-ionization mole fraction). We also varied the seed type between cesium and potassium. We also varied the oxidizer type between air (oxygen–nitrogen mixture, 21–79% by mole) and pure oxygen. Our results suggest that the ideal power density can reach exceptional levels beyond 1000 MW/m³ (or 1 kW/cm³) provided that the total absolute pressure can be reduced to about 0.1 atm only and cesium is used for seeding rather than potassium. Under atmospheric air–hydrogen combustion (1 atm total absolute pressure) and 1% mole fraction of seed alkali metal vapor, the theoretical volumetric power density is 410.828 MW/m³ in the case of cesium and 104.486 MW/m³ in the case of potassium. The power density can be enhanced using any of the following techniques: (1) reducing the total pressure, (2) using cesium instead of potassium for seeding, and (3) using air instead of oxygen as an oxidizer (if the temperature is unchanged). A seed level between 1% and 4% (pre-ionization mole fraction) is recommended. Much lower or much higher seed levels may harm the OCMHD performance. The seed level that maximizes the electric power is not necessarily the same seed level that maximizes the electric conductivity, and this is due to additional thermochemical changes caused by the additive seed. For example, in the case of potassium seeding and air combustion, the electric conductivity is maximized with about 6% seed mole fraction, while the output power is maximized at a lower potassium level of about 5%. We also present a comprehensive set of computed thermochemical properties of the seeded combustion gases, such as the molecular weight and the speed of sound. Full article

Fluorescent brighteners (FBs) are a class of chemicals extensively used in industrial and consumer products. Their environmental occurrences and potential health risks have raised significant concerns. However, the lack of analytical methods for FBs in human samples has hindered the accurate assessment of internal exposure levels. Addressing this gap, this study developed and validated a novel method for the simultaneous determination of 13 FBs at trace levels in human plasma using solid-phase extraction combined with HPLC-MS/MS. The method employed EMR-Lipid SPE columns, which can selectively adsorb phospholipids for plasma sample pre-treatment. Detection was achieved through positive ion electrospray ionization (ESI) in multiple reaction monitoring (MRM) modes. The results showed that all 13 FBs exhibited good linearity within their respective ranges, with correlation coefficients (R²) greater than 0.992. The method quantitation limits (MQLs) of the FBs ranged from 0.012 to 0.348 ng/mL, and the spiked recovery rates ranged from 61% to 98%. The method was successfully applied to analyze 10 adult plasma samples, detecting 10 FBs with total concentrations ranging from 0.221 to 0.684 ng/mL. This study provides a reliable analytical method for determining FBs in human plasma, providing a basis for further research on human internal exposure to FBs and associated health risk assessments. Full article

Coal dust seriously affects the underground working environment. The current water-spray dust reduction technology uses a large amount of water and has a poor effect on coal dust with poor wettability. This study proposed a clean and sustainable technology using plasma-activated water (PAW) to alter the wettability of coal dust and improve its dust control effect. The PAW was prepared and its physical and mathematical properties were tested by a device designed in-house. The influence of PAW on the wettability of coal dust was determined by the coal dust contact angle experiments. The effect of PAW on the surface morphology of coal dust was analyzed by a scanning electron microscope. The effect of PAW on the pore structure of coal dust was analyzed through the specific surface area and pore size experiments. The results showed that PAW contained a large number of active substances such as H₂O₂, NO₃⁻, and NO₂⁻, showing strong and stable oxidation. PAW could significantly reduce the instantaneous contact angle of coal dust, and the higher the degree of coal dust metamorphism, the more significant the reduction effect. The surface morphology, pore volume, specific surface area, and fractal dimension of the coal dust were significantly changed after PAW treatment. PAW could transform the non-uniform three-dimensional spatial distribution of the coal dust surface into an approximate two-dimensional planar distribution, thus enhancing the wettability of the coal dust. With the increase in PAW ionization intensity, the contact angle of long-flame coal was negatively correlated with the mesoporous pore volume. The contact angle of gas coal was negatively correlated with the micropore volume and micropore specific surface area, and was positively correlated with the mesopore volume. The contact angle of meager lean coal was positively correlated with the macropore specific surface area. The surface morphology, pore volume, specific surface area, and fractal dimension changes in coal dust treated with PAW can reveal the wettability enhancement mechanism to some extent. The results of the study can provide pre-theoretical guidance for the field application of PAW coal mine dust reduction technology. Full article

The hydrogen plasma smelting reduction process has the potential to drastically reduce the CO₂ emissions of the steel industry by using molecular, atomic and ionized hydrogen as a reducing agent for iron ores. To increase the hydrogen and thermal efficiency of the process, a pre-reduction and pre-heating stage should be incorporated in a future upscaling of an existing HPSR demonstration plant within the scope of the “SuSteel follow-up” project to a target capacity of 200 kg/h of iron ore. The determination of the optimal process parameters is followed by a review of possible reactor types. A fluidized bed cascade, a cyclone cascade and a rotary kiln are compared for this purpose. Their applicability for the hydrogen plasma smelting is discussed, based on their fundamental design and operational procedures. Additionally, critical features of the different reactor types are outlined. A cyclone cascade with at least 3 stages is proposed to be the optimal reactor for pre-heating and pre-reducing the input material for the upscaled hydrogen plasma smelting reduction demonstration plant, based on the assessment. Full article

Background: Hypothyroidism (HT) affects millions worldwide and can lead to various lipid disorders. The metabolic complexity and the influence of toxic elements in autoimmune and non-autoimmune HT subtypes are not fully understood. This study aimed to investigate the relationships between plasma lipidome, toxic elements, and clinical classifications of HT in unexposed individuals. Methods: Samples were collected from 120 adults assigned to a study group with Hashimoto’s disease and non-autoimmune HT, and a healthy control group. Quantification of 145 pre-defined lipids was performed by using triple quadrupole tandem mass spectrometry (TQ MS/MS) in multiple reactions monitoring (MRM) mode via positive electrospray ionization (ESI). Levels of toxic elements were determined using inductively coupled plasma mass spectrometry (ICP-MS). Results: Significant associations between altered levels of several components of the plasma lipidome and Al, Cd, Ni, As, and Pb with HT were found. We show metabolic differences in lysophosphatidylcholines (LPC) and phosphatidylcholines (PC) between HT and controls, with distinct predicted activation patterns for lysolecithin acyltransferase and phospholipase A2. Conclusions: There are significant changes in the lipidome profiles of healthy subjects compared to euthyroid HT patients treated with L-thyroxine, which are related to the type of hypothyroidism and non-occupational exposure to toxic elements. Full article

The ionosphere equatorial ionization anomaly (EIA) is usually characterized by two plasma density maxima in the Earth’s equatorial region. Merged EIA (MEIA) is a unique phenomenon in the evolution of the EIA. Currently, the occurrence characteristics of MEIA are still not well understood. In this study, we investigate the occurrence characteristics of nighttime MEIA using NASA Global-scale Observations of the Limb and Disk (GOLD) observations between October 2018 and the end of 2023. We found that the occurrence of nighttime MEIA exhibits solar cycle, seasonal, and local time variations. The occurrence rate of the MEIA is inversely dependent on solar activity. Occurrence of the MEIA maximizes near the equinoxes, with a primary (secondary) low occurrence rate near the June (December) solstice. In addition, occurrences of the MEIA are suppressed during the pre-reversal enhancement (PRE), resulting in relatively fewer events. Furthermore, it was found that the occurrence of the MEIA is not significantly dependent on the strength of geomagnetic activity. As far as we know, this study represents the first instance of utilizing observations from GOLD observations to investigate the characteristics of MEIA occurrences and their correlations with solar activity, season, and local time. Full article

Jieyu Pills (JYPs), a Chinese medicine consisting of 10 herbal elements, have displayed promising clinical effectiveness and low by-effects in the treatment of depression. Prior investigations mostly focused on elucidating the mechanism and therapeutic efficacy of JYPs. In our earlier study, we provided an analysis of the chemical composition, serum pharmacochemistry, and concentrations of the main bioactive chemicals found in JYPs. However, our precise understanding of the pharmacokinetics and metabolism remained vague. This study involved a comprehensive and meticulous examination of the pharmacokinetics of 13 bioactive compounds in JYPs. Using UPLC-Orbitrap Fusion MS, we analyzed the metabolic characteristics and established the pharmacokinetic parameters in both control rats and model rats with attention deficit hyperactivity disorder (ADHD) following oral administration of the drug. Before analysis, plasma samples that were collected at different time intervals after the administration underwent methanol pre-treatment with Puerarin used as the internal standard (IS) solution. Subsequently, the sample was chromatographed on a C18 column employing gradient elution. The mobile phase consisted of methanol solution containing 0.1% formic acid in water. The electrospray ionization source (ESI) was utilized for ionization, whereas the scanning mode employed was selected ion monitoring (SIM). The UPLC-Orbitrap Fusion MS method was subjected to a comprehensive validation process to assess its performance. The method demonstrated excellent linearity (r ≥ 0.9944), precise measurements (RSD < 8.78%), accurate results (RE: −7.88% to 8.98%), and appropriate extraction recoveries (87.83–102.23%). Additionally, the method exhibited minimal matrix effects (87.58–101.08%) and satisfactory stability (RSD: 1.52–12.42%). These results demonstrated adherence to the criteria for evaluating and determining biological material. The 13 bioactive compounds exhibited unique pharmacokinetic patterns in vivo. In control rats, all bioactive compounds except Ferulic acid exhibited linear pharmacokinetics within the dose ranges. In the ADHD model, the absorption rate and amount of most of the components were both observed to have increased. Essentially, this work is an important reference for examining the metabolism of JYPs and providing guidelines for clinical therapy. Full article

DAPB, a new molecule including danshensu, borneol, and a mother nucleus of ACEI (Angiotensin-converting enzyme inhibitors), is being developed as an antihypertensive candidate compound. A rapid, accurate, and sensitive ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was established and validated for the determination of DAPB in rat plasma. Chromatographic separation was performed on an Agilent SB-C18 column after protein precipitation by acetonitrile with a mobile phase consisting of acetonitrile and deionized water with 0.02% formic acid and 5 mM NH₄F (v/v) at a flow rate of 0.2 mL/min. Quantification was performed using electrospray positive ionization mass spectrometry in the multiple reaction monitoring (MRM) mode. The method was linear over the range of 2–1000 ng/mL. The intra- and inter-day precision was within 12%, with accuracies less than 7%. Stability was within the acceptable limits under various storage and processing conditions. No apparent matrix effect was detected. The validated method was applied to the pre-clinical pharmacokinetic study of DAPB after oral administration of 30 mg/kg and intravenous administration of 6 mg/kg in rats. Full article

Ionizing radiation exposure is known to induce molecular and cellular injury, inflicting a cascade of potentially catastrophic events leading to tissue and organ damage. Metabolomic analysis allows for the identification and quantification of small molecules downstream of genomic changes induced by radiation exposure. We aimed to characterize metabolomic changes that underscore the prefinal stage of lethally irradiated rhesus nonhuman primates (NHPs). Peripheral blood was drawn at baseline, post-exposure, as well as at the preterminal stage in NHPs (immediately prior to death in moribund NHPs) that did not survive exposure with 7.2 Gy total-body radiation (LD_70/60). Herein, we analyzed global metabolomic changes using ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight mass spectrometry (QTOF-MS) in plasma samples of NHPs collected at various timepoints in relation to irradiation. The overall goal was to identify metabolic shifts present immediately prior to death. Our findings showed radiation induced significant time-dependent metabolic perturbations when compared to pre-irradiation profiles, particularly in glycerophospholipid metabolism and steroid hormone biosynthesis and metabolism pathways. These findings provide valuable insights for identifying biomarkers for lethality, which may be helpful for triage during a mass casualty scenario. Full article

Monoclonal gammopathy of undetermined significance (MGUS) is a pre-malignant plasma cell disorder with an etiology that is incompletely understood. Modifiable risk factors and genetic predispositions likely interact to increase MGUS risk in specific individuals and populations. Identifying geographic prevalence patterns and modifiable risk factors is critical for understanding the etiology of MGUS. The aim of this review was to outline original research on MGUS prevalence across geographic locations and modifiable risk factors. We conducted a systematic review of 39 eligible studies from PubMed^®, Embase^®, and Web of Science^® written in English and published by February 2023. Our protocol was registered in accordance with PROSPERO guidelines. Studies were synthesized using Research Electronic Data Capture and appraised using the National Heart, Lung, and Blood Institute study quality assessment tools. The prevalence of MGUS ranged from 0.24% to 9% across geographic locations. Modifiable risk factors for MGUS include infections, autoimmune diseases, chronic inflammatory conditions, lifestyle factors, environmental exposures, and ionizing radiation. Therefore, the development of MGUS may be related to chronic antigenic stimulation and genetic aberrations that promote clonal proliferation of plasma cells. Prospective studies assessing gene–environment interactions are needed to further define risk factors for MGUS and inform screening and preventative strategies. Full article

In this study, samples underwent plasma electrolytic oxidation (PEO) treatment using Al/Ti tracer substrates for 5, 10, 20, 35, and 55 min. The ionization states were determined using Optical Emission Spectroscopy (OES). Microstructural and elemental analyses were conducted using scanning electron microscopy equipped with energy dispersive spectrometry (SEM-EDS). The structural organization and phase composition of the coatings were characterized using X-ray diffraction (XRD) and Raman spectroscopy, respectively. The research findings indicate that the early discharge stage is dominated by discharge within the pre-deposited Al layer, which undergoes gradual oxidation along the thickness direction, while Ti (0.25 wt%) is found on the coating surface. The power increase was 56% of the total increase from min 5 to min 10 of discharge. As discharge time increased, the spectral peaks corresponding to Ti gradually became stronger and were accompanied by gradual enhancement of the crystallinity of the anatase and rutile phases within the coating. The coating surface displayed closed and semi-closed pores in the middle of the discharge. After 55 min of discharge, amorphous SiO₂ was observed and Ti content on the coating surface increased to 4.59 wt%. Full article

Low-temperature plasma (LTP) oxidation has been widely used to study the mineralogy of the mineral matter existing in coal sources. The current study investigated the potential of LTP oxidation as a pre-treatment method to improve rare earth element (REE) leachability from coal and its by-products. Representative density-fractionated samples of Baker and Fire Clay coarse refuse seam materials were ground to a top size of 180 µm and subjected to low-temperature plasma oxidation. Subsequently, the treated samples were leached at 1% w/v solids concentration and 75 °C for 5 h using (i) de-ionized (DI) water, (ii) 0.1 mol/L of ammonium sulfate, and (iii) 1.2 mol/L of sulfuric acid. It was determined that LTP treatment improved REE leaching characteristics, especially the leaching of heavy REEs (HREE), existing in the lighter density fractions of the Baker seam coarse refuse material. For instance, the HREE recovery for the 1.6 specific gravity (SG) float fraction increased from 8% to 33% using 0.1 mol/L of ammonium sulfate solution after 32 h of LTP treatment. This finding indicated that HREEs associated with the organic matter were released by the LTP treatment and adsorbed onto the surfaces of highly negative charged mineral matter and was exchanged with ammonium to allow their recovery. Similarly, when using 1.2 mol/L of sulfuric acid, the HREE recovery increased from 23% to 53% for the 1.6 SG float fraction. Interestingly, LTP oxidation did not provide significant improvement in REE recovery from the 2.2 sink density fractions, which was likely due to its lower organic content. No significant benefits were observed when treating the Fire Clay coarse refuse material, which was likely due to the lack of organic affinity and the difficult-to-leach REE minerals associated with the coal source such as monazite, xenotime, and zircon. Conversely, high-temperature oxidation within a temperature range of 600–750 °C significantly improved REE leaching characteristics for both coal sources. Improvement in REE recovery was due to decarbonization of the material, clay dehydroxylation and subsequent conversion of liberated REE-bearing minerals into a more leachable form. However, increasing the temperature above 800 °C decreased REE recovery due to the conversion of meta-kaolinite into mullite, which is chemically stable. Full article

Gas plasma jet technology was recently identified as a potential adjuvant in the fight against cancer. Here, the partial ionization of gas yields the local formation of an exceptional variety of highly reactive oxygen (ROS) and nitrogen (RNS) species, which are considered the main actors of plasma-induced antitumor effects. Yet, fundamental knowledge in preclinical plasma research relies on the predominant use of two-dimensional cell culture systems, despite causing significant shifts in redox chemistries that largely limit translational relevance. So far, the intricacy of studying complex plasma–tissue interactions causes substantial knowledge gaps concerning the key mechanisms and therapeutical limitations of plasma treatment in a living organism. Identifying physiologically relevant yet simplified tissue models is vital to address such questions. In our study, a side-by-side comparison of conventional and pre-established hydrogel models emphasized this discrepancy, revealing a marked difference in plasma-induced toxicity related to species distribution dynamics. Chemically embedded, fluorescent reporters were further used to characterize reactive species’ fingerprints in hydrogels compared to liquids. In addition, a thirteen cell-line screening outlined the widespread applicability of the approach while indicating the need to optimize growth conditions dependent on the cell line investigated. Overall, our study presents important implications for the implementation of clinically relevant tissue culture models in preclinical plasma medicine in the future. Full article

Cefiderocol (C) is a parenteral siderophore cephalosporin with relevant inter-individual pharmacokinetic variability among critically ill patients, which may potentially affect effective drug exposure. Therapeutic drug monitoring (TDM) may concur in improving the real-time management of C therapy in clinics. In this study, we developed and validated a fast and sensitive Liquid Chromatography-Isotope Dilution Tandem Mass Spectrometry (LC-ITD-MS/MS) method for measuring C in human plasma microsamples, as small as 3 microliters. Analysis was preceded by a user-friendly pre-analytical single-step and was performed by means of a very fast chromatographic run of 4 min, followed by positive electrospray ionization and detection on a high sensitivity triple quadrupole tandem mass spectrometer operated in multiple reaction monitoring mode. The straightforward analytical procedure was successfully validated, based on the European Medicines Agency (EMA) guidelines, in terms of specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, limit of quantification, and stability. The novel method was successfully applied to TDM of C in more than 50 cases of critically carbapenem-resistant Gram-negative bacterial infections and enabled us to optimize antibiotic therapy. Full article

The ultrafast interaction of tightly focused femtosecond laser pulses with bulk dielectric media in direct laser writing (inscription) regimes is known to proceed via complex multi-scale light, plasma and material modification nanopatterns, which are challenging for exploration owing to their mesoscopic, transient and buried character. In this study, we report on the first experimental demonstration, analysis and modeling of hierarchical multi-period coupled longitudinal and transverse nanogratings in bulk lithium niobate inscribed in the focal region by 1030 nm, 300 fs laser pulses in the recently proposed sub-filamentary laser inscription regime. The longitudinal Bragg-like topography nanogratings, possessing the laser-intensity-dependent periods ≈ 400 nm, consist of transverse birefringent nanogratings, which are perpendicular to the laser polarization and exhibit much smaller periods ≈ 160 nm. Our analysis and modeling support the photonic origin of the longitudinal nanogratings, appearing as prompt electromagnetic and corresponding ionization standing waves in the pre-focal region due to interference of the incident and plasma-reflected laser pulse parts. The transverse nanogratings could be assigned to the nanoscale material modification by interfacial plasmons, excited and interfered in the resulting longitudinal array of the plasma sheets in the bulk dielectric material. Our experimental findings provide strong support for our previously proposed mechanism of such hierarchical laser nanopatterning in bulk dielectrics, giving important insights into its crucial parameters and opening the way for directional harnessing of this technology. Full article