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In this article we present the results of time-of-flight mass spectrometry of volatile products formed during the electrical breakdown of polyethylene terephthalate and polypropylene polymer films in high vacuum. During the breakdown of films, all the substance emitted from the breakdown channel is a gas of low-molecular products of destruction of macromolecules. The breakdown mass spectra do not contain lines of carbon molecules, the presence of which could indicate carbonation of the channel. To explain the formation of charge carriers, the ionization mechanism of destruction of macromolecules in an electric field is used without the involvement of impact ionization. The final stage of electrical breakdown (the flow of a high-density conduction current) occurs when the critical concentration of traps and electrons ≈1024 m–3 is reached. [ABSTRACT FROM AUTHOR]

The COVID-19 (SARS-CoV-2) pandemic increased the focus on preventing contamination with airborne pathogens (e.g. viruses, bacteria, and fungi) by reducing their concentration. Filtration, UV or ionization technologies could contribute to air purification of the indoor environment and inactivation of micro-organisms. The aim of this study was to identify the relevant literature and review the scientific evidence presented on the efficacy of filter and germicidal technologies (e.g. non-physical technologies) in air purification applications used to capture and inactivate micro-organisms and airborne viruses (e.g. SARS-CoV-2, rhinovirus, influenzavirus) in practice. A scoping review was performed to collect literature. Adopting exclusion criteria resulted in a final number of 75 studies to be included in this research. Discussion is presented on inactivation efficiencies of ultraviolet germicidal irradiation (UVGI) and ionization applications in laboratory studies and in practice. Specific attention is given to studies relating the use of UVGI and ionization to inactivation of the SARS-CoV-2 virus. Based on the consulted literature, no unambiguous conclusions can be drawn regarding the effectiveness of air purification technologies in practice. The documented and well-controlled laboratory studies do not adequately represent the practical situation in which the purifier systems are used. [ABSTRACT FROM AUTHOR]

The purpose of this review and commentary was to provide an historical and evidence-based account of organic acids and the biochemical and organic chemistry evidence for why cells do not produce metabolites that are acids. The scientific study of acids has a long history dating to the 16th and 17th centuries, and the definition of an acid was proposed in 1884 as a molecule that when in an aqueous solution releases a hydrogen ion (Hþ). There are three common ionizable functional groups for molecules classified as acids: 1) the carboxyl group, 2) the phosphoryl group and 3) the amine group. The propensity by which a cation will associate or dissociate with a negatively charged atom is quantified by the equilibrium constant (Keq) of the dissociation constant (Kd) of the ionization (Keq = Kd), which for lactic acid (HLa) vs. lactate (La-) is expressed as: Keq = Kd = [HLa] [La] =[HLa] = 4 677.351 4 (ionic strength = 0.01 Mol-L-1, T = 25 °C). The negative log10 of the dissociation pKd reveals the pH at which half of the molecules are ionized, which for HLa = 3.67. Thus, knowing the pKd and the pH of the solution at question will reveal the extent of the ionization vs. acidification of molecules that are classified as acids. [ABSTRACT FROM AUTHOR]

Although the comparison of fully differential ionization data for particle and antiparticle impact provides the ultimate tests of theoretical models, only very low antiparticle beam intensities are available. Hence, few experiments of this type have been performed. Therefore, available experimentally obtained single and double differential cross-sections, which are much easier to obtain, are compared in order to demonstrate differences when only the projectile mass or charge (+1 or −1) is changed. Included in the comparison are cross-sections calculated for positron and electron impact using a three-particle classical trajectory Monte Carlo method. The calculated cross-sections provide independent information about the ejected electron and the scattered projectile contributions, plus information about the impact parameters, all as functions of the collision kinematics. From these comparisons, suggestions as to where future investigations are both feasible and useful are provided. [ABSTRACT FROM AUTHOR]

While the existence of D-amino acids in peptides and proteins has recently been accepted in higher forms of life, their roles and importance are yet to be understood. The lack of analytical methods present for such epimeric and/or isomeric analyses often limits developments in the field. Studies have shown the elevated presence of epimeric and isomeric modifications to amyloid-beta (Aβ) peptides extracted from Alzheimer's disease patients. These modifications most frequently occur through aspartic acid and serine residues. Because such peptides are indistinguishable by mass alone, selective liquid chromatography tandem mass spectrometry analysis is required to differentiate such peptides. Herein, we examine MS/MS of tryptic fragments of Aβ peptides containing D-Asp, L-iso-Asp, D-iso-Asp, and/or D-Ser modifications. Peptide ionizability and fragmentation are explored through selected reaction monitoring, selected ion monitoring, and product ion scan. The results show the variability of ionization and fragmentation for many "identical mass peptides" and how these differences can affect the analysis of isomeric and epimeric peptides. [ABSTRACT FROM AUTHOR]

We present a new model designed to simulate the process of energetic particle precipitation, a vital coupling mechanism from Earth's magnetosphere to its atmosphere. The atmospheric response, namely excess ionization in the upper and middle atmosphere, together with bremsstrahlung X‐ray production, is calculated with kinetic particle simulations using the Geant4 Monte Carlo framework. Mono‐energy and mono‐pitch angle electron beams are simulated and combined using a Green's function approach to represent realistic electron spectra and pitch angle distributions. Results from this model include more accurate ionization profiles than previous analytical models, deeper photon penetration into the atmosphere than previous Monte Carlo model predictions, and predictions of backscatter fractions of loss cone electrons up to 40%. The model results are verified by comparison with previous precipitation modeling results, and validated using balloon X‐ray measurements from the Balloon Array for RBSP Relativistic Electron Losses mission and backscattered electron energy and pitch angle measurements from the Electron Loss and Fields Investigation with a Spatio‐Temporal Ambiguity‐Resolving CubeSat mission. The model results and solution techniques are developed into a Python package for public use. Plain Language Summary: The upper atmosphere and near‐Earth space interact with each other through the transport of charged particle (e.g., electrons) from space into the atmosphere in a process called energetic particle precipitation. This process disturbs the atmosphere and causes X‐rays to be generated, among other direct and indirect effects to the atmosphere, including ozone destruction. This work describes a physics‐based model that simulates this process across realistic input values for energy and electron velocity direction. Results of this work include an estimate of the number of excess ion‐electron pairs generated in the atmosphere from precipitation, how many electrons are lost to the atmosphere versus those that rebound and return to space, and the energy and amount of X‐rays generated by precipitation. The model outputs are checked using balloon‐based measurements of X‐rays in the middle atmosphere and by a low Earth orbiting satellite that spins to measure electrons heading toward and away from Earth. Key Points: A Geant4‐based model has been developed to simulate radiation belt energetic particle precipitation (EPP)Mono‐energy and mono‐pitch angle beams are simulated to be combined using inversion methods to represent EPP quantities of interestModel results and inversion methods are validated using remote and in‐situ measurements that compare favorably to modeled observations [ABSTRACT FROM AUTHOR]

The dichroism effects, i.e., asymmetries of the ionization probability with respect to the inversion of either the atomic orientation (magnetic dichroism, MD) or the circular polarization degree of the photon beam (circular dichroism, CD), are investigated using the time-dependent perturbation theory (PT). It is shown that the magnitude of these effects depends not only on the polarization states of the atom and laser pulse but also on the intensity and duration of the latter. We find that the CD can also be observed in the ionization of oriented initial bound states, which is impossible in long-pulse ionization. Predictions of our PT analysis are supported by the results obtained by numerical solutions of the time-dependent Schrödinger equation (TDSE) describing the ionization of the excited 2P-states of the hydrogen atom. [ABSTRACT FROM AUTHOR]

Vortices are structures known in our daily lives and observed in a wide variety of systems, from cosmic to microscopic scales. Relatively recent studies showed that vortices could also appear in simple quantum systems. For instance, they were observed experimentally and theoretically as isolated zeros in the differential cross section in atomic ionization processes by the impact of charged particles. In this work, we show that the appearance of these quantum vortices as point structures was not due to any intrinsic property of them, but to the use of restrictive geometries in their visualization. In particular, we show that by studying the fully differential cross section for hydrogen ionization by positron impact, these vortex points are actually a manifestation of a more complex and hitherto unexplored structure, a 3D "vortex surface". [ABSTRACT FROM AUTHOR]

During the past five decades, classical dynamics have been systematically used to gain insight on collision processes between charged particles and photons with atomic and molecular targets. These methods have proved to be efficient for systems in which numerical intensive quantum mechanical methods are not yet tractable. During the years, reaction cross sections for charge exchange and ionization have been scrutinized at the total and differential levels, leading to a clear understanding of the benefits and limitations inherent in a classical description. In this work, we present a review of the classical trajectory Monte Carlo method, its current status and the perspectives that can be envisaged for the near future. [ABSTRACT FROM AUTHOR]

Introduction: Families of disorders known as cancer are characterized by uncontrolled cell development and have the ability to spread or metastasis throughout the body. An essential and crucial part of cancer treatment is radiation therapy. High energy radiation is used to the cancerous tissues during radiation therapy to destroy the cancerous cells. Various intracranial targets have been treated with stereotactic radiosurgery with the leksell gamma knife for many years. Purpose: The most recent leksell Gamma Knife (GK) generation supports both frame based and frameless techniques. In current study search the appropriate material to made anew fixation tool to solve the problem found in the others fixation tool used in gamma knife Materials and methods: Thirty patients with Trigeminal Neuralgia (TN) underwent GK radiosurgery employing the GK version 11.3.1 (Icon) elekta. In the present research, the decision for 3D mask fixation or thermoplastic mask was made on a case by case basis with patients' preferences taken into consideration. The 3D mask's material is checked to make sure it won't cause problems with treatment before it is put on the patients. The elekta spherical phantom is used with an ionization chamber device (PTW Semi flex 3D 31021) applied to it in order to assess the dose rate for each fixation tool. Results: The ionization devices (PTW Semi flex 3D 31021) was used to compare dose rate for the 3D mask and thermoplastic. The dose rate for the 3D mask and thermoplastic are 0.0131, so that's a significant difference at level = 0.05. Conclusion: The 3D masks provide same results of thermoplastic for dose rate according to the test of ionization chamber that used in current study. [ABSTRACT FROM AUTHOR]

The electronic structure and ionization spectrum of γ-pyrone (4H-pyran-4-one) were calculated using the third-order algebraic diagrammatic construction method for the single-particle Green function [IP-ADC(3)] and some other high-level quantum chemical methods. The results of calculations were used to interpret its recently recorded photoelectron spectra. New assignments have been proposed for the nature of a series of photoelectron maxima of γ-pyrone located above 12 eV, where, according to calculations, the one-electron ionization pattern is disturbed due to electron correlation effects. The obtained results significantly change the interpretation of the spectrum available in the literature. [ABSTRACT FROM AUTHOR]

Manipulation of intense pulse propagation in gas-filled capillaries is desirable for various high-field applications. Tuning the parameters of the driving laser pulse and the working gas is the conventional approach, and it provides limited capability of control. Here we demonstrate through numerical simulations a practical scheme to control the propagation of intense pulses. A weak ultraviolet pulse is launched into a capillary with a negative delay with respect to a main infrared pulse. The pulses begin to temporally overlap due to dispersion. As the main pulse self-compresses, the control pulse is strongly red-shifted due to cross-phase modulation. The frequency shifts of the two pulses mitigate pulse walk-off and allow an efficient coupling, substantially extending the effective interaction length. This interesting phenomenon may benefit applications such as high-order harmonic generation. [ABSTRACT FROM AUTHOR]

We have calculated the electron and positron impact ionization of a set of molecules, S F 6 − n H n (n = 0 − 6) , S C l n (n = 1 − 6) , S F n − 1 C l (n = 1 − 6) and S F 5 X (X = C N , C F O) , for which there are much fewer data in the literature. We have optimized the targets, and their electric polarizability is calculated along with their orbital binding and kinetic energies within the Hartree–Fock approximation that serve as input to the Binary Encounter Bethe (BEB) model for both electron and positron ionization. Most of the targets are investigated for the first time, apart from S F 6 , for which we compared our data with various experimental and theoretical data, giving us a good comparison. [ABSTRACT FROM AUTHOR]

This year's Atomic Spectroscopy Award recipient is Andreas Riedo. For the past decade, Riedo's research has focused on the development of fundamental measurement methodologies using miniaturized laser ablation-desorption ionization mass spectrometry (LIMS or LMS) for the chemical (elements, isotopes, and molecules) analysis of complex mineral surfaces, including semiconductor crystalline solids and materials found in space exploration., Andreas Riedo of the Physics Institute at the University of Bern has won the 2023 Emerging Leader in Atomic Spectroscopy Award, which is presented by Spectroscopy magazine. This annual award, [...]

The variation among individual cells plays a significant role in many biological functions. Single-cell analysis is advantageous for gaining insight into intricate biochemical mechanisms rarely accessible when studying tissues as a whole. However, measurement on a unicellular scale is still challenging due to unicellular complex composition, minute substance quantities, and considerable differences in compound concentrations. Mass spectrometry has recently gained extensive attention in unicellular analytical fields due to its exceptional sensitivity, throughput, and compound identification abilities. At present, single-cell mass spectrometry primarily concentrates on the enhancement of ionization methods. The principal ionization approaches encompass nanoelectrospray ionization (nano-ESI), laser desorption ionization (LDI), secondary ion mass spectrometry (SIMS), and inductively coupled plasma (ICP). This article summarizes the most recent advancements in ionization techniques and explores their potential directions within the field of single-cell mass spectrometry.

The TiO2/CuO coatings were applied on pure titanium via PEO, observing the photocatalytic capacity for methylene blue (MB) degradation. Additionally, the effect of the ionization process at room temperature on the photocatalytic efficiency of the coatings was studied. A coating containing CuO nanoparticles (NPs) presented a more porous morphology. Phase analysis results proved that coatings containing CuO NPs were comprised of anatase and CuO phases, while the addition of ionized-CuO NPs into the electrolyte led to the formation of anatase, rutile, CuO, and TiP2O7. The CuO-incorporated coating exhibited 76 % efficient MB photodegradation. Most importantly, the introduction of 1 g/L CuO-ionized NPs at 25 °C increased photocatalytic efficiency to 90 % after 6 h of visible light illumination. Moreover, the optimum coating satisfied photocatalytic efficiency even after 3 runs. A deep investigation into the effect of photocatalytic parameters, including concentrations (2.5, 5, 10 and 15 ppm) and pH of pollutants (3 and 9), was also performed. Furthermore, appropriate scavengers such as isopropanol (0.1 mM), ascorbic acid (0.1 mM), and potassium bromate (0.1 mM) were employed to scrutinize the role of various photogenerated reactive species and to detail the photocatalytic mechanism.

New engineering technologies allow the creation of diagnostic devices for predicting the development of acute tissue ischemia of the extremities and determining the residual time until the removal of the tourniquet, and solving these tasks is particularly relevant during military actions. Acute limb ischemia is a sudden critical decrease in perfusion that threatens the viability of the limb. The incidence of this condition is 1.5 cases per 10 000 people per year. Acute ischemia occurs due to the blockage of blood flow in major arteries (embolism, thrombosis, trauma), leading to the cessation of adequate blood supply to metabolically active tissues of the limb, including the skin, muscles, and nerve endings. To address these issues, the article analyzes the changes in the impedance of biological tissue. The introduction and use of the coefficient of relative electrical conductivity, denoted as k, as a diagnostic criterion parameter, are justified. Experimental studies of changes in the coefficient of relative electrical conductivity k were conducted, confirming that the transition from exponential to linear dependencies of the coefficient establishes the degree of viability of the biological cell (tissue) and the moment of occurrence of reperfusion syndrome. It has been established that a deviation of the value of k by 10–15% from its unit value diagnoses the initial process of blood perfusion impairment and the development of ischemic tissue disease. The rate of change of k serves as a criterion for predicting the progression of the disease and as a corrective factor for therapeutic treatment.

High-order harmonic generation with high photon flux has been a challenging task in strong-field physics. According to the high-order harmonic generation process, the essential requirements for achieving efficient harmonic radiations inside a gas medium are the improvement of the induced atomic dipole moment amplitude of the single-atom response in the microscopic and the phase matching of the high harmonics in the macroscopic medium. In this work, we demonstrated a feasible approach to enhance the extreme-ultraviolet harmonics in the plateau region by increasing the intensity of the driving laser while keeping the laser energy constant. The simulation results showed that by increasing the laser intensity to the overdriven regime, the average extreme-ultraviolet harmonics yield in the plateau region is approximately twice as high as that obtained optimally in the conventional loose focusing geometry scheme by utilizing a relatively low-intensity driving laser with the same laser energy. The quantitative analysis of the harmonics generation process in the macroscopic medium and the phase matching revealed that the observed enhancement in harmonics can be attributed to the amplification of the induced atomic dipole moment amplitude of the single-atom response in the high-intensity driving laser and the favorable transient phase matching in the overdriven regime. Furthermore, the investigation of the driving laser indicated that the favorable transient phase matching is caused by the spatiotemporal reshaping of the driving laser in the overdriven regime. [ABSTRACT FROM AUTHOR]

For the control of fusion reactors, we need to accurately know all the possible reactions and collisional cross sections. Although large-scale trials have been performed over the last decades to obtain this data, many basic atomic and molecular cross section data are missing and the accuracy of the available cross sections need to be checked. Using the available measured cross sections and theoretical predictions of hydrogen atom ionization by proton impact, critical analysis of the data is presented. Moreover, we also present our recent classical results based on the standard classical trajectory Monte Carlo (CTMC) and quasi-classical trajectory Monte Carlo (C-QCTMC) models. According to our model calculations and comparison with the experimental data, recom-mended cross sections for ionization of hydrogen were presented in a wide range of pro-jectile impact energies. We found that, while in the low energy region, the experimental cross sections are very close to the C-QCTMC results, at higher energies, they are close to the results of our standard CTMC results. [ABSTRACT FROM AUTHOR]

The technological aspects of the light inorganic crystalline compounds suitable to create scintillation materials to detect charged particles and neutrons in a wide energy range have been examined. Among them, Li2CaSiO4:Eu was found to be a prospective candidate to control the valent state of the Rare Earth (RE) and to provide a high intensity of luminescence. It was demonstrated that the material has room for future improvement; however, this requires precise engineering of its composition—an experimental search of compositions or additives that will provide the maximum Eu2+/Eu3+ ratio to achieve a high scintillation light yield. The benefits of light inorganic materials are disclosed through the modeling of the linear density of nonequilibrium carriers along secondary particle tracks created in scintillators utilized for neutron detection. It is shown that oxide matrices have a larger linear density in comparison with halide crystalline compounds under alpha-particles and tritons, whereas light oxides can provide smaller numbers under protons. [ABSTRACT FROM AUTHOR]

Among the physicochemical properties of drugs, dissociation constant (pKa) is the most important parameter for the design and development of new and existing drug molecules. We report for the first time, the experimental determination of dissociation constant (pKa) for a frontline anti-tubercular drug isoniazid. Besides, pKa values of the two of its newly synthesized sulfonyl derivatives, N′-[(2,4,6-trimethylbenzene)sulfonyl]pyridine-4-carbohydrazide (SZ-I), N′-[(4-bromobenzene)sulfonyl]pyridine-4-carbohydrazide (SZ-II) were also determined. The approach adopted was UV–Visible spectrophotometry which is an established analytical method known for its accuracy and reproducibility. The spectrophotometric analysis was performed by measuring the absorbance values at various pH and the pKa values were then calculated using Henderson-Hasselbalch equation. The pKa values were found to be 3.0, 3.55 and 3.43 for Isoniazid (INH) and its sulfonyl derivatives SZ-I and SZ-II, respectively. [ABSTRACT FROM AUTHOR]

In this work, we discuss the effects of component ratios on plasma characteristics, chemistry of active species, and silicon etching kinetics in CF4 + O2, CHF3 + O2, and C4F8 + O2 gas mixtures. It was shown that the addition of O2 changes electrons- and ions-related plasma parameters rapidly suppresses densities of CFx radicals and influences F atoms kinetics through their formation rate and/or loss frequency. The dominant Si etching mechanism in all three cases is the chemical interaction with F atoms featured by the nonconstant reaction probability. The latter reflects both the remaining amount of fluorocarbon polymer and oxidation of silicon surface. [ABSTRACT FROM AUTHOR]

Multi-parameter study on the subsonic equilibrium air plasma flows in the cylindrical discharge channel of an induction RF-plasmatron IPG-3 with the maximum operating power of 1 MW is presented. Simulations are carried out by numerical solution of full Navier–Stokes equations coupled with a two-dimensional equation for high-frequency electric field; the discretization of the equations is performed on a staggered Cartesian mesh. An effective method for calculation of the transport coefficients for ionized multi-component air (including the plasma conductivity) in the temperature range 300–15000 K is applied, with the higher-order approximations by the Sonine polynomial in the Chapman–Enskog method. Simulation results are presented, including the flow fields, electric field, and thermodynamic parameters of the air plasma in the discharge channel of a high-power induction plasmatron. The results obtained reveal for the first time the structure and parameters of a plasma torch in a large-diameter (200 mm) discharge channel at powers up to 300 kW, providing the axial specific enthalpies at the channel outlet as high as 68 MJ/kg. [ABSTRACT FROM AUTHOR]

We use the large spectroscopic data set of the MOSFIRE Deep Evolution Field survey to investigate some of the key factors responsible for the elevated ionization parameters (U) inferred for high-redshift galaxies, focusing in particular on the role of star-formation-rate surface density (ΣSFR). Using a sample of 317 galaxies with spectroscopic redshifts z spec ≃ 1.9–3.7, we construct composite rest-frame optical spectra in bins of ΣSFR and infer electron densities, n e, using the ratio of the [O ii ] λ λ 3727, 3730 doublet. Our analysis suggests a significant (≃3 σ) correlation between n e and ΣSFR. We further find significant correlations between U and ΣSFR for composite spectra of a subsample of 113 galaxies, and for a smaller sample of 25 individual galaxies with inferences of U. The increase in n e—and possibly also the volume filling factor of dense clumps in H ii regions—with ΣSFR appear to be important factors in explaining the relationship between U and ΣSFR. Further, the increase in n e and SFR with redshift at a fixed stellar mass can account for most of the redshift evolution of U. These results suggest that the gas density, which sets n e and the overall level of star formation activity, may play a more important role than metallicity evolution in explaining the elevated ionization parameters of high-redshift galaxies. [ABSTRACT FROM AUTHOR]

Используя лидарные сигналы на длинах волн 561 и 532 нм в диапазоне высот 30-400 км, путем решения обратной задачи восстанавливаем коэффициенты рассеяния света, соответствующие этим длинам волн, что позволяет сравнить оптические характеристики термосферы, мезосферы и верхней стратосферы и определить соотношения между резонансным, рэлеевским и аэрозольным рассеянием света на разных высотах атмосферы. Используя коэффициенты рассеяния в термосфере, находим сечения рассеяния света на длинах волн 561 и 532 нм переходов возбужденных атомарных ионов кислорода и азота и объясняем, почему коэффициенты рассеяния для O+, 561 нм меньше чем для N+, 532 нм, в то время как концентрация O+ на два порядка выше чем N+. Полученные здесь результаты представляют интерес для понимания ионизационного эффекта солнечной активности на оптические характеристики атмосферы, которые определяют погодные и климатические изменения.

Author(s): Mahsa Torabizadeh [sup.1], Kourosh Tabar-Heydar [sup.1], Seyyed Hamid Ahmadi [sup.1] Author Affiliations: (1) grid.466618.b, 0000 0004 0405 6503, Faculty of Clean Technologies, Chemistry and Chemical Engineering Research Center of [...], In this study, an online solid-phase extraction-thermal desorption method coupled with gas chromatography-flame ionization detection was used to extract seven pyrethroids from tap water and agricultural wastewater. For this purpose, a metal-organic framework MIL-101(Cr) was synthesized, and its applicability as a solid-phase sorbent was studied. Several effective parameters of the extraction efficiency such as the amount of sorbent, sample volume, sample pH, and thermal desorption procedure were also explored. Moreover, molecular docking was used to predict and assess the nature of pyrethroids adsorption on MIL-101(Cr). Additionally, the molecular interactions and the binding energies were studied and calculated. The analytical performance of the proposed method showed an excellent linear dynamic range (r = 0.9953-0.9997) for pyrethroids in the range of 0.5-10 [mu]g/L and relative standard deviations less than 8.3% combined with satisfactory detection and quantification limits (below 0.20 and 0.9 [micro]g/L, respectively). Under the optimal conditions, the method was successfully applied for the determination of pyrethroids in real samples (tap water and wastewater) with satisfactory recoveries in the range of 85.1-97.2%.

Bioaccumulation of ionizable pharmaceuticals has been increasingly studied, with most reported aquatic tissue concentrations in field or laboratory experiments being from fish. However, higher levels of antidepressants have been observed in bivalves compared with fish from effluent‐dominated and dependent surface waters. Such observations may be important for biodiversity because approximately 70% of freshwater bivalves in North America are considered to be vulnerable to extinction. Because experimental bioaccumulation information for freshwater bivalves is lacking, we examined accumulation dynamics in the freshwater pondmussel, Sagittunio subrostratus, following exposure to a model weak acid, acetaminophen (mean (±SD) = 4.9 ± 1 µg L–1), and a model weak base, sertraline (mean (±SD) = 1.1 ± 1.1 µg L–1) during 14‐day uptake and 7‐day depuration experiments. Pharmaceutical concentrations were analyzed in water and tissue using isotope dilution liquid chromatography–tandem mass spectrometry. Mussels accumulated two orders of magnitude higher concentrations of sertraline (31.7 ± 9.4 µg g–1) compared to acetaminophen (0.3 ± 0.1 µg g–1). Ratio and kinetic‐based bioaccumulation factors of 28,836.4 (L kg–1) and 34.9 (L kg–1) were calculated for sertraline and for acetaminophen at 65.3 (L kg–1) and 0.13 (L kg–1), respectively. However, after 14 days sertraline did not reach steady‐state concentrations, although it was readily eliminated by S. subrostratus. Acetaminophen rapidly reached steady‐state conditions but was not depurated over a 7‐day period. Future bioaccumulation studies of ionizable pharmaceuticals in freshwater bivalves appear warranted. Environ Toxicol Chem 2023;42:1183–1189. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

The ionization of sputtered species in high power impulse magnetron sputtering of titanium, chromium, and aluminum targets is analyzed using Abel-inverted spectroscopic imaging to locate the position of ionization. From the spatial emission of neutrals, it is deduced that most of the sputtered titanium particles become ionized within 0.5 mm distance from the target, whereas sputtered aluminum or chromium can travel much further through the discharge before ionization occurs. Probe measurements reveal the reason for this difference to be the unusually high electron temperature of around 4.5 eV for titanium compared to 2.6 eV and 1.5 eV for aluminum and chromium as the target material, respectively. These probe measurements are then compared to a global model derived from the ionization region model. Excellent agreement between model and measurements can be reached, but only if the transport physics for the confinement of the species is adjusted. Using the model, the difference between the three discharges can be traced back to be mostly caused by the sputter yield. Thus, we propose that ionization in discharges with low-yield materials should generally be expected to occur closer to the target surface, leading the ions to be affected more strongly by the electric field across the magnetic trap region, resulting in a more severe deposition rate loss compared to high-yield materials. [ABSTRACT FROM AUTHOR]

The structure and evolution of wind-blown bubbles (WBBs) around massive stars has primarily been investigated using an energy-conserving model of wind-blown bubbles. While this model is useful in explaining the general properties of the evolution, several problems remain, including inconsistencies between observed wind luminosities and those derived using this formulation. Major difficulties include the low X-ray temperature and X-ray luminosity, compared to the model. In this paper, we re-examine the evolution, dynamics, and kinematics of WBBs around massive stars, using published ionization gasdynamic simulations of wind-blown bubbles. We show that WBBs can cool efficiently due to the presence of various instabilities and turbulence within the bubble. The expansion of WBBs is more consistent with a momentum-conserving solution, rather than an energy-conserving solution. This compares well with the dynamics and kinematics of observed wind bubbles. Despite the cooling of the bubble, the shocked wind temperature is not reduced to the observed values. We argue that the X-ray emission arise mainly from clumps and filaments within the hot shocked wind region, with temperatures just above 106 K. The remainder of the plasma can contribute to a lesser extent. [ABSTRACT FROM AUTHOR]

In order to study the effect of inorganic salt additives on the surface tension of a sodium dodecylbenzene sulfonate (SDBS) solution, the surface tension of the mixed system of six common inorganic salt additives, NaCl, CaCl2, AlCl3, Na2SO4, Na2CO3, and NaHCO3, and SDBS was measured, and the effects of the inorganic salt types, surfactant concentrations and inorganic salt concentrations on the surface tension of the SDBS solution were studied. On this basis, three inorganic salts, NaCl, CaCl2 and Na2SO4, were selected, and their effects on the critical micelle concentration (CMC) of the SDBS solution were studied. The experimental results showed that different inorganic salts had different effects on the surface tension of the SDBS solution. The order of effect of the six inorganic salts on the surface tension of the SDBS solution was CaCl2 > NaCl > Na2SO4 > NaHCO3 > Na2CO3 > AlCl3; when the mass fraction of the SDBS solution is high, the influence of the inorganic salts on the surface tension of the SDBS solution is relatively small; with an increase in the concentration of the preferred inorganic salt additives, the surface tension of the SDBS solution decreases first, then tends to be stable, and then increases; a reduction in the critical micelle concentration by the three selected inorganic salt additives shows the trend of 0.7% NaCl > 0.5% CaCl2 > 0.5% Na2SO4. [ABSTRACT FROM AUTHOR]