Ion Mass Research Articles

Deciphering the safeguarding role of cysteine residues in p53 against H2O2-induced oxidation using high-resolution native mass spectrometry

The transcription factor p53 is exquisitely sensitive and selective to a broad variety of cellular environments. Several studies have reported that oxidative stress weakens the p53-DNA binding affinity for certain promoters depending on the oxidation mechanism. Despite this body of work, the precise mechanisms by which the physiologically relevant DNA-p53 tetramer complex senses cellular stresses caused by H2O2 are still unknown. Here, we employed native mass spectrometry (MS) and ion mobility (IM)-MS coupled to chemical labelling and H2O2-induced oxidation to examine the mechanism of redox regulation of the p53-p21 complex. Our approach has found that two reactive cysteines in p53 protect against H2O2-induced oxidation by forming reversible sulfenates.

Facile Synthesis of Acyl-Hydrazone Composites Based on Hydrazide-Modified Formylated Polystyrene for Effective Removal of Heavy Metal Ions and Sulfides from Water.

In this study, waste polystyrene was modified and upgraded to prepare formylated polystyrene, and the modified polystyrene acetyl hydrazone (LT-HPA) was synthesized by condensation with polymethyl-propionyl-hydrazine. It is proven that the modification of the adsorption material is successful by various characterization methods. In the subsequent pollutant removal study, pH, mass, concentration, contact time, and salt ion interference were investigated. The optimal pH for Cu(II) and sulfide removal was 5 and 11, respectively, and the optimal mass of adsorbent was 1 g/L. It was found that the maximum removal rate of Cu (II) was 231.51 mg/g. The adsorption equilibrium time was less than 40 min. This is due to the good adsorption activity of acyl hydrazide groups on the skeleton for Cu (II) through coordination. The maximum desulfurization amount in 60 min was 370.21 mg/g, which was mainly caused by the oxidation of sulfides by surface oxidizing groups. Isotherm and kinetic studies show that the adsorption processes of Cu (II) and sulfides are consistent with the Langmuir model and pseudo-second-order kinetic model. Thermodynamic parameters show that the removal of Cu (II) and sulfides is a spontaneous endothermic process. The adsorption mechanism is mainly chemical adsorption, supplemented by physical adsorption. After 10 regenerated adsorption/desorption cycles, the removal rates of Cu (II) and sulfides remained above 85%, indicating that polystyrenesulfonate acetylhydrazone (LT-HPA) adsorption materials have good reusability. In addition, the adsorbent has good thermal stability, salt resistance, and environmental friendliness. In summary, the modified formylated polystyrene acetyl hydrazone (LT-HPA) has a good application prospect in the removal of copper(II) and sulfides and provides a fresh way for upgrading polystyrene.

Identification of a novel imidazole-derived GABA agonist isopropoxate: simultaneous detection and quantification of imidazole-derived analogs from human hairs in abused cases by LC-MS/MS.

Distribution and abuse of imidazole-derived γ-aminobutyric acid (GABA) agonists, such as etomidate and metomidate, and their analogs have been encountered frequently especially in China. The aim of this study was to identify etomidate, metomidate, propoxate, and isopropoxate more accurately by establishing a gas chromatography-mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) method and applying it to real forensic cases. Onemg of the seized powder was dissolved in 1mL of methanol, and subjected to GC-MS and LC-MS/MS. Hair samples were washed and cut into approximately 2mm sections, then ground to powder by a low-temperature grinder. Twenty mg of the hair powder was extracted with 1mL of methanol, and the supernatant was subjected to LC-MS/MS. Etomidate, metomidate, propoxate, and isopropoxate were chromatographically separated and each mass spectrum was obtained by GC-MS. For LC-MS/MS, tested validation data were all satisfactory. The seized powder samples contained isopropoxate, with an approximate content of 30.9%. Etomidate, etomidate acid, metomidate, and isopropoxate could be determined in the submitted hairs, ranging from 2.89 to 8.09ng/mg, 0.0591-0.177ng/mg, 0.342-2.77ng/mg, and 33.2-130ng/mg, respectively. Mass spectra and ion chromatograms of etomidate, metomidate, isopropoxate, and propoxate were obtained by GC-MS. We have also established a simultaneous and reliable analytical method for etomidate, etomidate acid, metomidate, and isopropoxate in human hair by LC-MS/MS. This is the first report to present analytical results of a novel imidazole-derived GABA agonist isopropoxate in drug abuse cases.

A novel inductive oven design to produce high-current, moderate mass ion beams for superheavy element searches

A novel inductive oven design to produce high-current, moderate mass ion beams for superheavy element searches

A laboratory study to assess the physico-chemical properties of BioRoot RCS and BioRoot Flow exposed to citric acid and EDTA irrigating solutions.

To assess physico-chemical properties of BioRoot RCS (powder-to-liquid formulation) and BioRoot Flow (pre-mixed formulation) after exposure to citric acid (CA) and EDTA. BioRoot RCS and BioRoot Flow specimens (5 × 2mm) were incubated for 28 days at 37°C before being treated with test solution (distilled water, 17% EDTA, 10% CA, 20% CA or 40% CA). Changes in mass, ion release (inductively coupled plasma optical emission spectroscopy), phase composition (X-ray diffraction and Raman spectroscopy), surface morphology (scanning electron microscopy and energy dispersive spectroscopy) were evaluated. The Shapiro-Wilk, Levene and one-way ANOVA, followed by Tukey's test, were used for statistical analysis (p < 0.05). The greatest mass loss, ion release and surface morphological changes (pores and cracks) of BioRoot RCS and BioRoot Flow occurred in 10% and 20% CA. No significant differences were identified between BioRoot RCS and BioRoot Flow in distilled water and EDTA (p > 0.05), whereas BioRoot Flow was significantly more soluble than BioRoot RCS in all CA solutions (p < 0.001). The main phase identified for both materials was zirconium oxide, which remained unaffected by the solutions. Within the limitations of the study, 10% and 20% CA were more effective than distilled water, 17% EDTA and 40% CA in terms of dissolving BioRoot RCS and BioRoot Flow. The BioRoot Flow was significantly more soluble in all CA solutions than BioRoot RCS. 10% and 20% CA solutions may have a potential to be used as a solvent for hydraulic calcium silicate sealers during endodontic retreatment.

Effect of Fe Doping on the Crystal Structure and Dielectric Properties of LiGaCr4O8 Breathing Pyrochlore

In this study, LiGaCr4−xFexO8 (x = 0, 0.2, 0.4, 0.6) ceramics are synthesized using the solid‐phase reaction method. The effects of Fe doping on the lattice structure and dielectric properties are systematically examined using X‐ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and dielectric measurements. It is found from XRD analysis that the evolution of lattice constant decreases from 8.2552 Å at x = 0 to 8.2449 Å at x = 0.6, demonstrating a lattice contraction with doping. SEM shows a grain size reduction and irregular structures with higher Fe doping levels developed. The grain size decreases from 1.716 μm at x = 0 to 1.155 μm at x = 0.6. Due to Fe doping, the Raman spectroscopy obviously changes in high‐frequency phonon modes. The F2g1 and A1g modes shift to higher frequencies due to the reduction in lattice constant, while the F2g2, F2g3, and Eg modes shift to lower frequencies due to the increased ionic mass caused by the heavier Fe ions. Notably, Fe doping increases the dielectric constant and reduces the dielectric loss, especially at higher doping level. In these results, it is suggested that moderate Fe doping improves dielectric properties, offering potential applications in microwave and high‐frequency devices.

Li+ Ionic Mass Transfer Accompanied with Electrodeposition of Li Metal in High Concentration Electrolyte

Li metal is a promising material for the negative electrode of next-generation secondary batteries because of very large capacity density. However, it is very difficult to keep uniformity of electrode morphology during repeating cycles. The charging reaction is corresponding to the electrodeposition of Li metal. Li metal forms dendrites very easily in the electrodeposition process. Dendrite is very typical non-uniform shape and causes the further current distribution to the electrode surface. The distribution accelerates the non-uniform electrodeposition, and then induces the short circuit phenomenon in the worst case. It is indispensable to understand the morphological variation and control the electrode surface shape during the charging and discharging of Li metal negative electrode for the realization of very high energy density batteries.In general, the electrodeposition of metals is strongly influenced by the ionic mass transfer in the vicinity of the electrode surface. The ionic mass transfer rate is related with the concentration overpotential and decrease of the surface concentration induces the increase the overpotential of the electrode reaction, and the depletion of metal ions become trigger of the dendrite formation. Our previous studies found the Li metal dendrite is induced without the depletion of Li+ ion at the electrode surface. Further, it is noteworthy that the morphology of Li metal dendrite has many kinds of shape. This specialty of Li metal is due to the surface layer called by “Solid Electrolyte Interphase (SEI)”. This layer is formed by the reaction between the Li metal and chemical species in the electrolyte solution. Therefore, it is dependent on the composition of the electrolytes. It is necessary to understand not only the ionic mass transfer but also the nature of SEI layer. In this study, Li+ ionic mass transfer rate was in-situ measured by holographic interferometry microscope and the characterization of SEI was conducted by cryo-STEM-EELS technique. High concentration electrolytes were utilized and current density dependence of surface concentrations, morphological variation, and the characteristics of SEI on the electrodeposited Li metal were discussed. We would like to report these details in the presentation on the day.

Determination of Am full isotope compositions (241Am, 242Am, 243Am) at trace level by multiple-collector - ICP-MS with a desolvation device for sample introduction

Americium isotopes are crucial in various nuclear-related fields such as nuclear fuel cycle, nuclear forensics and nuclear safeguards. This study introduces enhanced methodologies for precise determination of 242Am/241Am and 243Am/241Am in trace americium by employing Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) and Total Evaporation-Thermal Ionization Mass Spectrometry (TE-TIMS). We established a standard-sample bracketing (SSB) method with uranium-certified reference material (U CRM) to correct the mass fractionation and ion counter gain yield among different isotopes in MC-ICP-MS. The new methods were successfully applied to an aliquot of an 241Am progeny sample, an 241Am activity standard solution and an in-house Am isotopic working standard, achieving detection limits of 10−7 for 242Am and 243Am. Analysis requires an aliquot containing about 1 ng of 241Am for MC-ICP-MS with a desolvation device for sample introduction and about 5 ng for TE-TIMS to determine 242Am/241Am ratios close to 10−5 and 243Am/241Am ratios close to 10−4, with observed relative standard deviations of 0.2 %. Comparative analysis of 242Am/241Am and 243Am/241Am using classical TE-TIMS and the newly developed MC-ICP-MS confirms their consistency within uncertainties, validating the precision of MC-ICP-MS in americium isotope ratio determination. These findings indicate that the 241Am activity standard sample was directly sourced from irradiated material rather than from a 241Pu solution, highlighting the methodology's applicability to nuclear forensics and nuclear fuel cycles.

Experimental and zero-dimensional simulation study of an embedded bismuth LaB6 hollow cathode

Experiments and zero-dimensional simulation were conducted to evaluate the discharge performance of an embedded bismuth LaB6 hollow cathode. The experimental results demonstrate that the embedded bismuth hollow cathode can operate in diode mode without any external heating, with a mass flow rate of approximately 0.21 mg/s. In Keeper-cathode mode, the discharge voltage for bismuth was slightly lower than that of xenon and exhibited strong stability, with a maximum discharge variation of less than 0.5 V at a discharge current of 2 A. The simulation results showed that at the same mass flow rate, the electron and ion densities in the insert region of the bismuth hollow cathode were higher than those of xenon, whereas the opposite was true for the orifice region. Notably, at discharge currents below 4 A, the power deposition of bismuth in both the insert and orifice regions was lower than that of xenon, indicating reduced erosion.

SiO2 sputtering by low-energy Ar+, Kr+, and Xe+ ions in plasma conditions

Modern plasma technologies applied for nm-size devices require localizing ions’ impact within up to atomic layer to avoid uncontrollable damage of underlying structures. The decrease in energy of ions incident on a surface is one of the ways to achieve this. In this work, SiO2 sputtering by Ar+, Kr+, and Xe+ ions at energies of 20–200 eV was studies in the low-pressure ICP-discharge at a plasma density typical for plasma processing. The rf-bias waveform tailoring due to high discharge asymmetry allowed generating and controlling ion narrow energy spectrum with FWHM 5 ± 2 eV. Real time in-situ control over ion composition and flux as well as sputtering rate provided accurate determination of the SiO2 sputtering yield, Y(Ei). It is shown that at ion energy above ∼70 eV, the “classical” kinetic sputtering mechanism prevails. In this case, Y(Ei) rapidly grows with ion energy, while decreasing with the decrease in ion mass. Below ∼70 eV, the change of Y(Ei) is strongly slow down while the sputtering yield still stays high enough (>10−3), demonstrating the plasma impact on the sputtering mechanism. The obtained trends of Y(Ei) under the plasma exposure are discussed in light of possible SiO2 surface modification studied by AFM and angular XPS analysis.

GC–MS-based metabolite fingerprinting reveals the presence of novel anticancer compounds in the microcolonial fungus Aureobasidium sp. TD-062 from the under-explored Thar Desert

Aureobasidium sp., strain TD-062, a micro colonial black yeast, was obtained as part of a screening program from the Thar Desert of India, which has been inadequately explored for novel microorganisms/bioactive metabolites. The anticancer activity of aqueous and organic solvent extracts of culture supernatant of TD-062 was investigated against A-375 myeloma and MCF-7 breast cancer cell lines. Following column chromatography, bioactive fractions were subjected to GC–MS analysis in two cycles. The GC–MS metabolite fingerprinting revealed 20 compounds belonging to various chemical groups. Further, based on observed and calculated mass ion spectra, retention time, and retention indices, many compounds could be considered novel. The second purification cycle resulted in three compounds- ATD-1, ATD-2 and ATD-3 with different calculated retention indices from that of the nearest matching compounds, squalene and tocopherol. In silico prediction study of their ADMET profiles, suggests that these new compounds have a suitable contour for use as safe anticancer drugs, without the toxicity normally associated with anticancer compounds.

A simplified coaxial ion trap mass analyzer: Characterization of the simplified toroidal ion trap with a rectilinear ion guide

A new miniature coaxial ion trap mass analyzer with a rectilinear ion guide has been constructed using a combination of planar and cylindrical electrodes. The results reported here focus on characterizing the performance of the rectilinear ion guide and simplified toroidal ion trap components. The simplified toroidal ion trap was found to have an ion capacity in excess of 105 ions and mass spectral resolution of 0.5–0.6 when used as a mass analyzer. The ion storage efficiency within the toroidal trapping region was evaluated and found the stored ion population decreased exponentially with storage time. Ion losses depended slightly on the stored βz condition. Ion losses within the toroidal region are attributed primarily to field instabilities at the intersection point of the two components while charge exchange reactions were observed but considered a minor loss mechanism. The ability to mass selectively ejection ions of a specific mass from the toroidal trapping region was characterized and found to approach 100 % efficiency under appropriate ejection conditions.

Confined mass transport in two-dimensional capillary

Abstract Over the past decade, nanofluidics has undergone significant expansion, propelled by advances in crafting artificial channels at nanometric and sub-nanometric scales with diverse geometries. Central to this domain, two-dimensional capillaries have risen as a pivotal research platform, marked by their angstrom-level precision, unparalleled wall surface smoothness, and clearly defined surface charge states. Their advent has profoundly deepened our understanding of mass transport dynamics, spanning gases, water molecules, and ions, shedding light on the complex interactions among various influencing factors and revealing a range of previously undiscovered physical phenomena. This review delves into the development of 2D capillaries, the principal fluid transport phenomena observed within, and the critical elements that affect these processes. We also touch on a fascinating discovery - the quantum liquid friction seen in water moving over carbon surfaces. In anticipation of future explorations in nanofluidics, we envision a trajectory aimed at emulating the efficiency levels of biological protein channels, setting the stage for a new era of scientific inquiry and technological innovation.

Mercury’s plasma environment after BepiColombo’s third flyby

Understanding Mercury’s magnetosphere is crucial for advancing our comprehension of how the solar wind interacts with the planetary magnetospheres. Despite previous missions, several gaps remain in our knowledge of Mercury’s plasma environment. Here, we present findings from BepiColombo’s third flyby, offering a synoptic view of the large scale structure and composition of Mercury’s magnetosphere. The Mass Spectrum Analyzer (MSA), Mass Ion Analyzer (MIA), and Mass Electron Analyzer (MEA) on the magnetospheric orbiter reveal insights, including the identification of trapped energetic hydrogen (H+) with energies around 20 keV e−1 evidencing a ring current, and a cold ion plasma with energies below 50 eV e−1. Additionally, we observe a Low-Latitude Boundary Layer (LLBL), which is a region of turbulent plasma at the edge of the magnetosphere, characterized by bursty ion enhancements, indicating an ongoing injection process in the duskside magnetosphere flank. These observations during cruise phase provide a tantalizing glimpse of future discoveries expected from the Mercury Plasma Particle Experiment (MPPE) instruments after orbit insertion, promising broader impacts on our understanding of planetary magnetospheres.

Isomeric Speciation of Bisbenzoxazine Intermediates by Ion Spectroscopy and Ion Mobility Mass Spectrometry.

Bisbenzoxazines (BisBz) are a relevant model for the diverse bifunctional benzoxazines that are used to increase the polybenzoxazines cross-linking extensions and modulate the final resin properties for various usages. The presence of side products and intermediates during monomer formation can influence the resin characteristics by inducing chain termination and ramifications, affecting the polymerization and cure processes. This work investigated the diverse isomeric intermediates and side products that are present during the BisBz formation from bisphenol A, aniline, and formaldehyde by ion mobility coupled to tandem mass spectrometry (MS/MS) and ion spectroscopy techniques. The species detected in this work suggest that these multifunctional phenols open diverse concurrent reaction pathways based on two main reactive steps: (i) the imine/iminium phenol attack to form a phenylamino intermediate and (ii) the formaldehyde attack followed by dehydration to form the oxazine ring. The species observed also support previous studies of the benzoxazine formation mechanism and showcase the application of advanced analytical techniques in studying complex chemical systems.

Rapid discovery of natural antioxidants in Hypericum japonicum: Dual roles of the liquid phase mobile phase as extraction and separation solvent

Hypericum japonicum is a traditional folk medicine with various bioactivities such as hepatoprotective, antioxidant, and anti-tumorous. The antioxidant effect of H. japonicum is one of the most prominent effects due to its responsibility for many of its activities. To clarify active natural substance, the antioxidant properties of H. japonicum were preliminarily assessed by ferric reducing–antioxidant power (FRAP), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and Oxygen radical absorbance capacity (ORAC), as well as superoxide dismutase (SOD). Then, a straightforward and effective method named online liquid extraction-high performance liquid chromatography combined with ABTS antioxidant assay and mass spectrometry (OLE-HPLC-ABTS/Q-TOF-MS) was developed to swiftly and directly discover the antioxidants in H. japonicum. Using mobile phase as extraction and separation reagent, coupled with online activity analysis and compounds identification by high-resolution MS, the online system enables rapid screening of natural antioxidant bioactives from complex mixture. By using it, a total of 9 compounds including flavonoids and phenolic acids characterized by retention time, precise mass, and fragmentation ions in MS/MS spectra showed antioxidant action. Finally, the antioxidant and SOD activity of main found active compounds were validated by in vitro experiment assay and molecular docking. In summary, these results suggested that H. japonicum could be considered as a potential source of natural antioxidants, and the online integrated system might become a promising candidate for the natural antioxidants discovery in the future.

Electrical-Modulated Flexible Acoustic Metamaterial: Enhancing Low-Frequency Absorption via an Ionic Electroactive Polymer.

The growing concern over low-frequency noise pollution resulting from global industrialization has posed substantial challenges in noise attenuation. However, conventional acoustic metamaterials, with fixed geometries, offer limited flexibility in the frequency range adjustment once constructed. This research unveiled the promising potential of ionic electroactive polymers, particularly ionic polymer-metal composites (IPMCs), as a superior candidate to design tunable acoustic metamaterial due to its bidirectional energy conversion capabilities. The previously perceived limitations of the IPMC, including slow reaction and high energy expenditure, owning to its inherent sluggish intermediary ionic mass transport process, were astutely leveraged to expedite the attenuation of low-frequency sound energy. Both our experimental and simulation results elucidated that the IPMC can generate voltage potentials in response to acoustic pressure at frequencies significantly higher than those previously established. In addition, the peak absorption frequency can be effectively shifted by up to 45.7% with the application of a 4 V voltage. By further integration with a microperforated panel (MPP) structure, the developed metamaterial absorbers can achieve complete sound absorption, which was continuously tunable under minimal voltage stimulation across a wide frequency spectrum. In addition, a microslit structure IPMC metamaterial absorber was designed to realize modulation of the perforation rate, and the absorption peak can be shifted by up to 79.2%. These findings signify a pioneering application of ionic intelligent materials and may pave the way for further innovations of tunable low-frequency acoustic structures, ultimately advancing the pragmatic deployment of both soft intelligent materials and acoustic metamaterials.

Fingerprinting alkaloids for traceability: Semi-untargeted UHPLC-MS/MS approach in raw lupins as a case study

Lupin seeds are recognized for their nutritional value and potential health benefits, but they contain also a significant amount of alkaloids, an anti-nutritive class of compounds, which vary significantly in composition within and between species due to environmental factors. In this study, we developed a predictive multi-experiment approach using ultra-high performance liquid chromatography coupled with triple quadrupole with linear ionic trap tandem mass spectrometry (UHPLC-QqQ-LIT-MS/MS) for comprehensive alkaloid profiling and geographical classification of Lupinus albus L. samples originating from four different Italian regions. Six targeted quinolizidine alkaloids were detected and 21 other alkaloids were putatively identified. Hierarchical Cluster Analysis (HCA) and partial least squares discriminant analysis (PLS-DA) were applied to explore the data structure and successfully classify samples according to their geographical origin. The data demonstrate the efficacy of the developed approach in providing valuable insights in alkaloid profiles of lupin seeds and their potential as markers for geographical traceability.

An advancement of the gravimetric isotope mixture method rendering the knowledge of the spike purity superfluous

The gravimetric isotope mixture method is the primary method to determine absolute isotope ratios. This method, however, depends on the existence of suitable spike materials and knowledge of their purities. Determining the purity of the spikes can be tedious and labour-intensive. In this publication, an advancement of the gravimetric isotope mixture method, rendering the determination of the purity of the spike materials unnecessary, is presented. The advancement combines mass spectrometry and ion chromatography leading to an approach being independent of the purity of the spike materials. In the manuscript the mathematical background and the basic idea of the novel approach are described using a two-isotope system like copper or lithium.Graphical abstract

The linear Paul Trap's Confined Stability Area for 40Ca+ Ions

تقدم تكنولوجيا الكم طرقًا حسابية واتصالات ومحاكاة وقياسًا جديدة. تحتاج أجهزة الكمبيوتر التقليدية إلى المساعدة في حل المشكلات المهمة مثل التحليل بسبب الزيادات الهائلة في وقت الحساب. ومع ذلك، تستخدم أجهزة الكمبيوتر الكمومية ميكانيكا الكم لحجم المشكلة الأسي الفرعي ويمكنها محاكاة الطبيعة على المستوى الكمي. يهتم العلماء بشكل متزايد بتطوير أجهزة الكمبيوتر الكمومية باستخدام ذرات متأينة مفردة في مصائد باولي. تمثل الحالة الأساسية لكل أيون أقل قيمة ممكنة للبت الكمي. تم استخدام الأيونات المحتجزة 40Ca+ في إحدى الدراسات كمثال على الكيوبت الكمومي. تم استخدام برنامج MATLAB على العوامل النموذجية التي تؤثر على الحالة المقيدة وتأثيراتها. يجب أن تكون الحلول مستقرة في كلا الاتجاهين، مما يتطلب حصرًا ثلاثي الأبعاد لمعادلة ماثيو. تؤثر المتغيرات على المسافة من مركز المصيدة لنهاية القطب، وجهد UDC، وكتلة الأيون، والترددات الراديوية. تم استخدام جهد متغير للتحكم وإظهار تأثيره على سلسلة محددة من الأيونات المحاصرة. يهدف هذا البحث إلى فهم أفضل للظروف المثلى للحجز وحركة الأيونات من الحالة (4S1/2) إلى الحالة (4P1/2) بالرنين. تخضع الحالة الكمومية للتعديل والتغيير، مما يجعلها أداة واعدة لحل المشكلات المعقدة.