Search

Some of the authors of the present research group have previously reported mass spectrometric detection of [PdAu9(PPh3)8(CN)]2+ (PdAu9CN) by atmospheric pressure plasma (APP) irradiation of [MAu8(PPh3)8]2+ (PdAu8) in methanol and proposed based on density functional theory (DFT) calculations that PdAu9CN is constructed by inserting a CNAu or NCAu unit into the Au–PPh3 bond of PdAu8 [Emori et al., J. Chem. Phys. 155, 124312 (2021)]. In this follow-up study, we revisited the structure of PdAu9CN by high-resolution ion mobility spectrometry on an isolated sample of PdAu9CN with the help of dispersion-corrected DFT calculation. In contradiction to the previous proposal, we conclude that isomers in which an AuCN unit is directly bonded to the central Pd atom of PdAu8 are better candidates. This assignment was supported by Fourier transform infrared and ultraviolet–visible spectroscopies of isolated PdAu9CN. The simultaneous formation of [Au(PPh3)2]+ and PdAu9CN suggests that the AuCN species are formed by APP irradiation at the expense of a portion of PdAu8. These results indicate that APP may offer a unique method for transforming metal clusters into novel ones by generating in situ active species that were not originally added to the solution. [ABSTRACT FROM AUTHOR]

Proflavine, a fluorescent cationic dye with strong absorption in the visible, has been proposed as a potential contributor to diffuse interstellar bands (DIBs). To investigate this hypothesis, it is essential to examine the spectra of cold and isolated ions for comparison. Here, we report absorption spectra of proflavine ions, trapped in a liquid-nitrogen-cooled ion trap filled with helium-buffer gas, as well as fluorescence spectra to provide further information on the intrinsic photophysics. We find absorption- and fluorescence-band maxima at 434.2 ± 0.1 and 434.7 ± 0.3 nm, corresponding to a Stokes shift of maximum 48 cm−1, which indicates minor differences between ground-state and excited-state geometries. Based on time-dependent density functional theory, we assign the emitting state to S2 as its geometry closely resembles that of S0, whereas the S1 geometry differs from that of S0. As a result, simulated spectra involving S1 exhibit long Franck-Condon progressions, absent in the experimental spectra. The latter displays well-resolved vibrational features, assigned to transitions involving in-plane vibrational modes where the vibrational quantum number changes by one. Dominant transitions are associated with vibrations localized on the NH2 moieties. Experiments repeated at room temperature yield broader spectra with maxima at 435.5 ± 1 nm (absorption) and 438.0 ± 1 nm (fluorescence). We again conclude that prevalent fluorescence arises from S2, i.e., anti-Kasha behavior, in agreement with previous work. Excited-state lifetimes are 5 ± 1 ns, independent of temperature. Importantly, we exclude the possibility that a narrow DIB at 436.4 nm originates from cold proflavine cations as the band is redshifted compared to our absorption spectra. [ABSTRACT FROM AUTHOR]

Insulin bound with ligand molecules can improve its bioavailability in oral formulations. In this work, the interactions between insulin and bile acids of taurocholic acid (TCA) and glycocholic acid (GCA) are characterized using different mass spectrometry (MS) methods. Electrospray (ESI)–MS analysis revealed that GCA and TCA could interact with insulin individually or together through non-covalent bonds, and the products included mGCA-insulin, nTCA-insulin, and mGCA-nTCA-insulin complexes. Their binding stoichiometry, relative intensity ratio (IRa), and binding affinity were determined. ESI–MS/MS data and the calculated association constants both suggest that TCA has stronger affinity to insulin than GCA. The mixtures of various insulin, GCA, and TCA complexes with different charge states were separated, and distinct trend lines were observed using ion mobility mass spectrometry (IMMS). Moreover, liposomes containing insulin and GCA and/or TCA were prepared, and directly characterized using ESI–MS, and the interaction products of insulin with GCA and TCA were found in the liposome formulation. AutoDock was used to simulate molecular binding and select binding sites between insulin and GCA or TCA to explore the interaction mechanisms. The findings in this work could help understand the mechanism of action of insulin protection with bile acids in the body. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The document "Contributors to the Pioneering Investigators collection 2024: Part 3" from Chemical Communications profiles various researchers from around the world. These researchers are involved in diverse fields such as biomass conversion technology, renewable energy research, electrocatalysis, and materials science. They have received recognition for their work, including awards, fellowships, and editorial positions in prestigious journals. [Extracted from the article]

Rationale: The volatile organic compounds (VOCs) of Alpinia katsumadai Hayata (AKH) play a key role in determining its effects such as organoleptic properties, medicinal properties, and consumer preferences. The nonmedicinal parts (roots, fibrous roots, stems, leaves, and shells) in AKH are also rich in VOCs and different degrees of antibacterial activity. Therefore, it is important to comprehensively characterize the VOCs in different parts of AKH and learn about their potential antimicrobial abilities. Methods: In this study, headspace gas chromatography‐ion mobility spectrometry (HS‐GC‐IMS) and headspace solid‐phase microextraction gas chromatography–mass spectrometry (HS‐SPME‐GC‐MS) were used to comprehensively investigate the compositional characteristics and differences of roots, fibrous roots, stems, leaves, shells, and seeds in AKH. Multivariate statistical analysis was used to determine the differential VOCs in different parts of AKH. The inhibition zone diameter method was used to compare the antibacterial ability of different parts. Results: HS‐GC‐IMS and HS‐SPME‐GC‐MS analyses identified 67 and 125 VOCs, respectively. Multivariate statistical analysis showed the differences in the six parts is obvious. Compounds such as (E)‐2‐heptenal and thymol were selected as potential VOCs to distinguish six sites of AKH. In general, the inhibition effect of the volatile oils from shell and root on the two colonies was better, and the volatile oils of the four parts of AKH have better inhibitory effect on Staphylococcus aureus. Conclusion: This research conducted a comprehensive analysis of the fundamental volatile components in AKH. It subsequently elucidated the distinctions and specificities in different parts. The antibacterial effect of volatile oil in different parts was further compared, which was conducive to finding alternative parts for seeds in some active aspects, and the utilization of AKH was more sufficient. [ABSTRACT FROM AUTHOR]

People with severe mental illness have high rates of obesity, type 2 diabetes, and cardiovascular disease. Emerging evidence suggests that metabolic dysfunction may be causally linked to the risk of severe mental illness. However, more research is needed to identify reliable metabolic markers which may have an impact on mental health outcomes, and to determine the mechanisms behind their impact. In the METPSY research study, we will investigate the relationship between metabolic markers and clinical outcomes of severe mental illness in young adults. We will recruit 120 young adults aged 16–25 years living in Scotland with major depressive disorder, bipolar disorder, schizophrenia, or no severe mental illness (controls) for a prospective observational study. We will assess clinical symptoms at three in-person visits (baseline, 6 months, and 12 months) using the Structured Clinical Interview for DSM-5, and collect blood samples at each of these visits for agnostic profiling of metabolic biomarkers through an untargeted metabolomic screen, using the rapid hydrophilic interaction liquid chromatography ion mobility mass spectrometry method (RHIMMS). Participants will also complete remote assessments at 3 and 9 months after the baseline visit: Ecological Momentary Assessments to measure mental health, wrist actigraphy to measure rhythms of rest and activity, and continuous glucose monitoring to measure metabolic changes. Throughout the 12-month enrolment period, we will also measure objective markers of sleep using a radar sleep monitor (Somnofy). Using advanced statistical techniques and machine learning analysis, we will seek to better understand the mechanisms linking metabolic health with mental health in young adults with schizophrenia, bipolar disorder, and severe depression. Clinical trial number: Not applicable [ABSTRACT FROM AUTHOR]

Background: Currently, the procedures and methods applied in biological and medical fields for the determination of reactive oxygen and nitrogen species (RONS), primarily rely on spectrophotometric techniques, which involve the use of colorimetric reagents. While these methods are widely accepted, they exhibit significant limitations from an analytical standpoint, particularly due to potential inaccuracies, artifacts, and pronounced susceptibility to matrix effects. The purpose of this Technical Note is to demonstrate the application of ion chromatography—a robust and well-established analytical technique—for the quantification of RONS produced in cell culture media through the exposure to cold atmospheric plasma (CAP), an innovative therapeutic approach for cancer treatment, known as CAP indirect treatment. In addition, the present protocol proposes to apply the pharmacokinetics principles to the RONS generated in plasma-treated liquids (PTLs) following CAP exposure. Methods: The strategy involves elucidating the kinetic profiles of certain characteristic species by evaluating their half-life in the specific media used for cell cultures and investigating their "pharmacokinetic" (PK) profile. In this approach the drug dose is represented by the plasma power and the infusion time corresponds to the exposure time of the culture medium to CAP. Volume-dependent results were shown, focusing on nitrites and nitrates activities, justifying cellular inhibition. Results: This methodology enables the correlation of the PTL biological effects on different cell lines with the PK profiles (dose/time) obtained via ion chromatography. Conclusions: In conclusion, being a simple and green method, it could be used as an alternative to toxic reactions and analytical techniques with higher detection limits, while achieving good resolution. [ABSTRACT FROM AUTHOR]

The process of aging was crucial in enhancing the aroma quality of Huangjiu. Gas chromatography electronic nose (GC-E-Nose), gas chromatography-mass spectrometry (GC–MS), and gas chromatography-ion mobility spectrometry (GC-IMS) were employed to detect the variations in aroma among five samples aged for varying years (5–11). A comprehensive analysis revealed the presence of 85 compounds in the Shaoxing Huangjiu, twenty of which were identified as crucial contributors to its flavor profile through odor activity values analysis. The volatile aroma components of Huangjiu exhibited notable variations among different aging years. Additionally, the concentration and diversity of key aroma compounds increased with prolonged aging. At the same time, quantitative descriptive sensory analysis showed that aging could enhance the ester and acid aroma of Huangjiu. Moreover, based on variable importance for the projection, seven potential aroma markers such as diethyl succinate, ethyl butyrate, and furfural were screened out, which were the major compounds that caused the flavor differences of aged Huangjiu. The results offer valuable theoretical support for illustrating and regulating the quality of Huangjiu during its aging process. [ABSTRACT FROM AUTHOR]

Di-isopropyl methyl phosphonate (DIMP) has no major commercial uses but is a by-product or a precursor in the synthesis of the nerve agent sarin (GB). Also, DIMP is utilized as a simulant compound for the chemical warfare agents sarin and soman in order to test and calibrate sensitive IMS instrumentation that warns against the deadly chemical weapons. DIMP was measured from 2 ppbv (15 μg m−3) to 500 ppbv in the air using a pocket-held ToF ion mobility spectrometer, model LCD-3.2E, with a non-radioactive ionization source and ammonia doping in positive ion mode. Excellent sensitivity (LoD of 0.24 ppbv and LoQ of 0.80 ppbv) was noticed; the linear response was up to 10 ppbv, while saturation occurred at >500 ppbv. DIMP identification by IMS relies on the formation of two distinct peaks: the monomer M·NH4+, with a reduced ion mobility K0 = 1.41 cm2 V−1 s−1, and the dimer M2·NH4+, with K0 = 1.04 cm2 V−1 s−1 (where M is the DIMP molecule); positive reactant ions (Pos RIP) have K0 = 2.31 cm2 V−1 s−1. Quantification of DIMP at trace levels was also achieved by GC-MS over the concentration range of 1.5 to 150 μg mL−1; using a capillary column (30 m × 0.25 mm × 0.25 μm) with a TG-5 SilMS stationary phase and temperature programming from 60 to 110 °C, DIMP retention time (RT) was ca. 8.5 min. The lowest amount of DIMP measured by GC-MS was 1.5 ng, with an LoD of 0.21 μg mL−1 and an LoQ of 0.62 μg mL−1 DIMP. Our results demonstrate that these methods provide robust tools for both on-site and off-site detection and quantification of DIMP at trace levels, a finding which has significant implications for forensic investigations of chemical agent use and for environmental monitoring of contamination by organophosphorus compounds. [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dansyl labeling is a widely used approach for enhancing the detection of small molecules by UV spectroscopy and mass spectrometry. It has been successfully applied to identify and quantify a variety of biological and environmental specimens. Despite clear advantages, the dansylation reaction has found very few applications in the study of proteins. We reasoned that the mild labeling conditions, small size, and rapid reaction could be beneficial for studying protein structure and dynamics. To test this, we investigated the impact of dansylation on protein fold, stability, protein–protein, and protein–cofactor interactions. We selected two model proteins, myoglobin and alcohol dehydrogenase, for analysis using native mass spectrometry and ion mobility mass spectrometry. Our work establishes the utility of dansyl chloride as a covalent probe to study protein structure and dynamics under native conditions. [ABSTRACT FROM AUTHOR]

One of the main objectives of the ion mobility spectrometry (IMS) technique is to reduce moisture in detection systems, which causes the formation of ion clusters and ion water and a reduction in formed clusters' activity. Thus, one of the methods limiting moisture in a sampling injection system is to use hydrophobic polymeric membranes. The use of membranes with high permeability relative to the analysed organic compounds is required, including toxic agents in air (TAAs). Such requirements align with those of polydimethylsiloxane (PDMS) membranes. Unfortunately, thin PDMS membranes are not mechanically resistant. In this study, relatively thin PDMS membranes were reinforced with fine mesh fabric supports. These supports were chemically modified with selected oligoglycol derivatives and finally coated with PDMS. The obtained membranes were tested for water permeability and TAA simulants. [ABSTRACT FROM AUTHOR]

During the course of our ongoing study of the diversity of Thai fungi and their secondary metabolites, numerous specimens within the Hypoxylaceae have been characterised by traditional morphology, chemotaxonomy using ultra-high-performance liquid chromatography coupled to diode array detection and ion mobility tandem mass spectrometry (UHPLC-DAD-IM-MS/MS), and molecular phylogenetic analyses. MS/MS-based analysis of the major stromatal metabolites of a newly identified taxon, Hypoxylon luteogranulatum, indicated the production of distinct compounds compared to the azaphilone and binaphthalene pigments commonly found in the Hypoxylaceae, aside from the presence of the chemotaxonomic marker binaphthalene tetrol (BNT). Further analysis suggested that one of the major metabolites had the molecular formula C13H13NO3, identical to hypoxyvermelhotin A, a yellow pigment so far exclusively found in Hypoxylon lechatii. Its identity was confirmed after purification by preparative high-performance liquid chromatography with nuclear magnetic resonance (NMR) data, and genome analysis of H. lechatii revealed the presence of different hybrid polyketide synthases-non-ribosomal peptide synthetases (PKS-NRPS) hybrid clusters. Despite chemotaxonomic similarities with H. lechatii, we propose a new species, which is morphologically distinct from H. lechatii. Our molecular phylogenetic study provides substantial evidence distinguishing H. luteogranulatum clearly from H. lechatii and allied members within the Hypoxylaceae. Additionally, future studies are needed to better understand the ecological behaviour of H. luteogranulatum and identify the ecological role of the vermelhotin-like molecules within this putative interaction. [ABSTRACT FROM AUTHOR]

Background: The detection of explosives in crime scene investigations is critical for forensic science. This study explores the application of laser desorption (LD) ion mobility spectrometry (IMS) as a novel method for this purpose utilising a new IMS prototype developed by MaSaTECH. Methods: The LD sampling technique employs a laser diode module to vaporise explosive traces on surfaces, allowing immediate analysis by IMS without sample preparation. Chemometric approaches, including multivariate data analysis, were utilised for data processing and interpretation, including pre-processing of raw IMS plasmagrams and various pattern recognition techniques, such as linear discriminant analysis (LDA) and support vector machines (SVMs). Results: The IMS prototype was validated through experiments with pure explosives (TNT, RDX, PETN) and explosive products (SEMTEX 1A, C4) on different materials. The study found that the pre-processing method significantly impacts classification accuracy, with the PCA-LDA model demonstrating the best performance for real-world applications. Conclusions: The LD-IMS prototype, coupled with effective chemometric techniques, presents a promising methodology for the detection of explosives in forensic investigations, enhancing the reliability of field applications. [ABSTRACT FROM AUTHOR]

Background: Non‐invasive biomarkers may reduce post‐colonoscopy colorectal cancer (CRC) rates and colonoscopy overuse in Lynch syndrome. Unlike faecal immunochemical test (FIT), faecal volatile organic compounds (VOCs) may accurately detect both advanced and non‐advanced colorectal neoplasia. Aim: The aim of this study was to evaluate the potential of faecal VOCs—separately and with FIT—to guide optimal colonoscopy intervals in Lynch syndrome. Methods: Prospective longitudinal multicentre study in which individuals with Lynch syndrome collected faeces before and after high‐quality surveillance colonoscopy. VOC‐patterns were analysed using field asymmetric ion mobility spectrometry (FAIMS) and gas chromatography‐ion mobility spectrometry (GC‐IMS) followed by machine learning pipelines, and combined with FIT at 2.55 μg Hb/g faeces. Gas chromatography time‐of‐flight mass spectrometry analysed individual VOC abundance. Results: Among 200 included individuals (57% female, median 51 years), 62 had relevant neoplasia at colonoscopy: 3 CRC, 6 advanced adenoma (AA), 3 advanced serrated lesion (ASL), and 50 non‐advanced adenoma (NAA). Respective sensitivity and negative predictive value for CRC and AA (and also ASL in case of FAIMS) were 100% and 100% using FAIMS (54% specificity), and 89% and 99% using GC‐IMS (58% specificity). Respective sensitivity and specificity for any relevant neoplasia were 88% and 44% (FAIMS) and 84% and 28% (GC‐IMS); accuracy did not significantly improve upon VOC‐FIT. VOC‐patterns differed before and after polypectomy (AUC 0.70). NAA showed decreased faecal abundance of butanal, 2‐oxohexane, dimethyldisulphide and dimethyltrisulphide. Conclusions: In Lynch syndrome, faecal VOCs may be a promising strategy for postponing colonoscopy and for follow‐up after polypectomy. Our results serve as a stepping stone for large validation studies. Trial Registration: NL8749 [ABSTRACT FROM AUTHOR]

Trace explosive detection is an essential aspect for ensuring public safety. Ion mobility spectrometry (IMS) is an effective technique for detecting explosives and compounds related to explosives. IMS technique operating at atmospheric pressure has numerous advantages, including simple structure, clear spectra, high sensitivity, and fast analysis speed, making it widely applied in fields such as on-site detection of explosives. However, the limitations of traditional ion mobility spectra lie in their low resolution and lack of fine structural information, making it difficult to differentiate ions with similar mobility, which can easily lead to false positive results. To address this issue, referencing collision-induced dissociation (CID) in mass spectrometry, explosives can be similarly dissociated under atmospheric pressure through radio frequency strong electric fields. This process generates rich secondary fragment ions, conferring mobility spectra with structural information of the analyte. Through simulation studies of the electric field of the drift tube and optimization of several structural parameters of the fragmentation grid, a tandem ion mobility spectrometry with a dual ion gate structure was developed. By changing the switch status of the ion gate and fragmentation grid, this system is capable of selecting specific parent mobility ions for fragmentation under ambient pressure. Three representative substances, ammonium nitrate (AN), cyclotrimethylene trinitramine (RDX), and pentaerythritol tetranitrate (PETN), along with their dopants, were used to obtain primary mobility spectra of explosives under atmospheric pressure. Based on their mobility spectra, parent ions were separated and then subjected to strong electric field fragmentation to acquire secondary fragment ions. Under the conditions of 170 č and atmospheric pressure, AN achieves a dissociation rate of 95% for the parent ion at a frequency of 2.6 MHz and a peak voltage of 900 V. The dissociation rates for the product ions [RDX+NO2] − of RDX and product ions [RDX+Cl]− of RDX doped with C2Cl6 are 93% and 15% at a frequency of 2.6 MHz and a peak voltage of 1 500 V, respectively. The dissociation rates for [PETN+NO3] − and [PETN+Cl]− are 54% and 48%, respectively. The degree of ion fragmentation is mainly influenced by the structural characteristics of the parent ions, while increasing the electric field and temperature further promote their fragmentation. Although introducing radio frequency electric fields may result in a certain degree of ion loss, the combination of secondary fragments and parent ion drift times provides additional chemical information for explosive detection, potentially reducing false positives in detection of explosive. [ABSTRACT FROM AUTHOR]

In this study, Au nano-particles--CdS quantum dot was synthesized and introduced as a new nanocomposite adsorbent for extraction and pre--concentration of rabeprazole (RAB). The drug analyte was quantitatively retained by the adsorbent from the large volume of real samples. The desorbed RAB was determined using ion mobility spectrometry with a corona discharge ionization source. Under instrumental optimum conditions (drift voltage: 6700 V, corona voltage: 2200 V, drift gas flow rate: 600.0 ml min-1, carrier gas flow rate: 300.0 ml min-1, injection port temperature: 220 ºC, cell temperature: 180 ºC and pulse width: 100 µs) RAB was determined in the range of 0.1-25.0 ng including two linear segments. The limit of detection was 0.03 ng and also limit of quantitation was found to be 0.1 ng. The precision values (RSDs%) were 7.8% and 6.9% for 1.0 and 10.0 ng of RAB, respectively. Finally, the developed method was applied for the determination of RAB in biological (human urine and serum) and pharmaceutical (tablet) samples with satisfactory recovery results. [ABSTRACT FROM AUTHOR]

When electrolyte solutions are confined in micro- and nanochannels their conductivity is significantly different from those in a bulk phase. Here we revisit the theory of this phenomenon by focusing attention on the reduction in the ion mobility with the concentration of salt and a consequent impact to the conductivity of a monovalent solution, from bulk to confined in a narrow slit. We first give a systematic treatment of electrophoresis of ions and obtain equations for their zeta potentials and mobilities. The latter are then used to obtain a simple expression for a bulk conductivity, which is valid in a concentration range up to a few molars and more accurate than prior analytic theories. By extending the formalism to the electrolyte solution in the charged channel the equations describing the conductivity in different modes are presented. They can be regarded as a generalization of prior work on the channel conductivity to a more realistic case of a nonzero reduction of the electrophoretic mobility of ions with salt concentration. Our analysis provides a framework for interpreting measurements on the conductivity of electrolyte solutions in the bulk and in narrow channels. [ABSTRACT FROM AUTHOR]

Understanding and controlling the chemical behavior of iron and iron oxide clusters requires accurate thermochemical data, which, because of the complex electronic structure of transition metal clusters, can be difficult to calculate reliably. Here, dissociation energies for Fe 2 + , Fe2O+, and Fe 2 O 2 + are measured using resonance enhanced photodissociation of clusters contained in a cryogenically cooled ion trap. The photodissociation action spectrum of each species exhibits an abrupt onset for the production of Fe+ photofragments from which bond dissociation energies are deduced for Fe 2 + (2.529 ± 0.006 eV), Fe2O+ (3.503 ± 0.006 eV), and Fe 2 O 2 + (4.104 ± 0.006 eV). Using previously measured ionization potentials and electron affinities for Fe and Fe2, bond dissociation energies are determined for Fe2 (0.93 ± 0.01 eV) and Fe 2 − (1.68 ± 0.01 eV). Measured dissociation energies are used to derive heats of formation ΔfH0( Fe 2 + ) = 1344 ± 2 kJ/mol, ΔfH0(Fe2) = 737 ± 2 kJ/mol, ΔfH0( Fe 2 − ) = 649 ± 2 kJ/mol, ΔfH0(Fe2O+) = 1094 ± 2 kJ/mol, and ΔfH0( Fe 2 O 2 + ) = 853 ± 21 kJ/mol. The Fe 2 O 2 + ions studied here are determined to have a ring structure based on drift tube ion mobility measurements prior to their confinement in the cryogenic ion trap. The photodissociation measurements significantly improve the accuracy of basic thermochemical data for these small, fundamental iron and iron oxide clusters. [ABSTRACT FROM AUTHOR]

Chlamydiosis is the major infectious disease responsible for significant morbidity and mortality in free-living koalas. Recently, it was reported that 28.5% of koalas infected with chlamydiosis were presented with no overt clinical signs. Identification and quantification of changes in plasma biomarkers' fluctuations have the potential to enhance C. pecorum detection and facilitate the monitoring of therapeutic efficacy of antibiotics to treat this disease in koalas. Therefore, concentrations of the essential amino acid tryptophan, tryptophan's metabolite kynurenine, and the kynurenine:tryptophan ratio were quantified by high-performance liquid chromatography in the plasma of clinically normal koalas (n = 35), koalas identified with chlamydial disease (n = 35) and koalas that had other non-chlamydial co-morbidities (n = 10). Results showed that there was a significant difference between the clinically normal versus diseased, and clinically normal versus 'other' (both p < 0.001) in kynurenine plasma concentrations and kynurenine:tryptophan ratio; and also between the clinically normal and diseased in tryptophan plasma concentrations (p = 0.001). Proposed reference ranges of tryptophan, kynurenine, and kynurenine:tryptophan ratio in koalas are: 4.27–10.4 μg/mL, 0.34–1.23 μg/mL, and 0.05–0.22, respectively. Proposed optimal cut-off points to differentiate between clinically normal and diseased are: ≤ 4.75 μg/mL (tryptophan), ≥ 0.88 μg/mL (kynurenine), and ≥ 0.12 (kynurenine:tryptophan); and ≤ 7.67 μg/mL (tryptophan), ≥ 1.18 μg/mL (kynurenine), and ≥ 0.16 (kynurenine:tryptophan) to differentiate between released/recovered and euthanised of the diseased/'other' koalas. Significant differences in haematological and biochemical analytes were in the plasma globulins between the clinically normal and diseased koalas (p = 0.01), and in alkaline phosphatase between the clinically normal and 'other' koalas (p = 0.03). Although these potential biomarkers, especially tryptophan, may not be specific for detecting C. pecorum from the rest of the population, kynurenine and the kynurenine:tryptophan ratio may have a role in identifying unhealthy koalas from the clinically normal ones, irrespective of the underlying cause. [ABSTRACT FROM AUTHOR]

Ion mobility spectrometry is successfully used as a sensor technology for different applications. A feature of this method is that characteristic ion mobility spectra are obtained for each measurement rather than a sum signal. The spectra result from the different drift velocities of ions in a drift tube at atmospheric pressure. In this study, we investigated the ion formation processes and the quantitative response of isoprene, monoterpenes and monoterpenoids as a function of the temperature of the spectrometer using a tritium ionization source. These substances are important target analytes in atmospheric monitoring and in the analysis of essential oils in different matrices. A drift tube temperature above 120 °C permitted the most sensitive detection of isoprene and monoterpenes, while 80 °C was sufficient for the sensitive detection of most terpenoids. Dimer ions were formed for isoprene over the whole temperature range. The ionization processes of monoterpenes and terpenoids were strongly influenced by the temperature. At temperatures of 40 °C, adduct ions were formed in addition to MH+ ions for monoterpenes. Enhanced temperatures provided a single peak with the same drift time for all monoterpenes. Structural differences influenced the ion formation of terpenoids, and much more complex spectra were obtained. The nature of the product ions changed depending on the temperature. [ABSTRACT FROM AUTHOR]

Rationale: Mycobacterial species contain high concentrations of mycolic acids in their cell wall. Mycobacteria can pose a threat to both human health and the environment. Mass spectrometry lipidomic characterization can identify bacterial species and suggest targets for microbiological interventions. Due to the complex structures of mycolic acids and the possibility of isobaric isomers, multiple levels of separation are required for complete characterization. In this study, cyclic ion mobility (cIM) mass spectrometry (MS) was used for the analysis, separation and fragmentation of mycolic acids isomers from the bacterial species Gordonia amarae and Mycobacterium bovis. Methods: Mycolic acid isomers were interrogated from cultured G. amarae biomass and commercially available M. bovis mycolic acid extracts. These were infused into a cIM‐enabled quadrupole time‐of‐flight MS. Ions of interest were non‐simultaneously selected with the quadrupole and passed around the cyclic ion mobility device multiple times. Fragment ion analysis was then performed for the resolved isomers of the quadrupole‐selected ions. Results: Repeated passes of the cIM device successfully resolved otherwise overlapping MA isomers, allowing isomer isolation and producing an ion‐specific post‐mobility fragmentation spectrum without isomeric interference. Conclusions: Mycolic acids (MA) isomers from G. amarae and M. bovis were resolved, resulting in a high mobility resolution and low interference fragmentation analysis. These revealed varying patterns of MA isomers in the two species: G. amarae's most abundant ion of each set of MA has 1–2 conformations, while the MA + 2 m/z the most abundant ion of each set has 3–6 conformations. These were resolved after 70 passes of the cyclic device. M. bovis' most abundant ion of each keto‐MA set has 2 conformations, while the keto‐MA + 2 m/z has 1–2 conformations. These were resolved after 75 passes. [ABSTRACT FROM AUTHOR]

Rationale: The 1, 2‐unsaturated derivatives of (1‐4) linked disaccharides serve as versatile building blocks for synthesizing biologically active compounds. Distinguishing between four pairs of stereoisomers in mixtures presents a challenging task. In this study, disaccharide derivatives are analyzed as alkali metal adducts using electrospray ionization tandem mass spectrometry (ESI‐MS/MS), both as individual compounds and in mixtures by ion mobility mass spectrometry (IMS). Methods: Electrospray ionization (ESI) in combination with tandem mass spectrometry (MS/MS) in positive mode was employed to differentiate lithium adduct ions of hexa‐acetyl/hexa‐benzyl‐D‐lactals, and hexa‐acetyl/hexa‐benzyl‐D‐maltals, along with their corresponding 2‐C‐branched malonates. The high resolving power of trapped ion mobility spectrometry (TIMS) with the imeX™ functionality rapidly identified different metal adducts (Li, Na, Cs) as individual isomers and separated mixtures of stereoisomers. The measured collisional cross section (CCS) values were analyzed in relation to predicted CCS values. Results: MS/MS spectra of the [M + Li]+ ions of glycal disaccharide analogues exhibited typical cross‐ring and glycosidic bond cleavages. Collision‐induced dissociation (CID) spectra provided insights into their fragmentation behavior, allowing differentiation of (1‐4) linked disaccharides. TIMS technology delivered adjustable ion mobility resolution for suitable separation of the four sets of stereo isomeric compounds. However, accurately predicting CCS values to differentiate between respective isomeric pairs using the SigmaCCS program for sodium adducts is only partially achievable. Conclusions: ESI CID spectra of [M + Li]+ adduct ions for individual glycal disaccharide analogues facilitate the discrimination between alpha and beta (1‐4) linked unsaturated disaccharides and their 2‐C‐branched analogues. Through optimized experimental conditions, complete baseline ion mobility separation of stereoisomer pairs of the Cs adducts is achieved. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The increasing popularity of plant-based drinks has led to an expanded consumer market. However, available quality control technologies for plant-based drinks are time-consuming and expensive. Two alternative quality control methods, gas chromatography with ion mobility spectrometry (GC-IMS) and an electronic nose, were used to assess 111 plant-based drink samples. Principal component analysis (PCA) and linear discriminant analysis (LDA) were used to compare 58 volatile organic compound areas of GC-IMS gallery plots and 63 peptide sensors of the electronic nose. PCA results showed that GC-IMS was only able to completely separate one sample, whereas the electronic nose was able to completely separate seven samples. LDA application to GC-IMS analyses resulted in classification accuracies ranging from 15.4% to 100%, whereas application to electronic nose analyses resulted in accuracies ranging from 96.2% to 100%. Both methods were useful for classification, but each had drawbacks, and the electronic nose performed slightly better than GC-IMS. This study represents one of the first studies comparing GC-IMS and an electronic nose for the analysis of plant-based drinks. Further research is necessary to improve these methods and establish a rapid, cost-effective food quality control system based on volatile organic compounds. [ABSTRACT FROM AUTHOR]

MS-based omics technologies are uncovering novel biomarkers and elucidating the complex pathophysiology of type 1 diabetes (T1D), setting the stage for transformative diagnostic and therapeutic strategies. The integration of machine learning with omics data is refining T1D predictive models, advancing the field towards more accurate and dynamic risk assessments for precision diabetes management. Cutting-edge MS methodologies, including ion mobility spectrometry, are enhancing the speed and depth of biological analyses, enabling rapid, high-throughput diagnostics suitable for large-scale studies. Innovations in single-cell and spatial MS, such as nanoPOTS, are revealing molecular heterogeneity within T1D, providing a granular view of disease onset and progression critical for targeted therapies. The discovery of T1D-associated neoepitopes and metabolites through advanced omics techniques is providing new insights into disease mechanisms, potentially leading to novel, personalized interventions. Type 1 diabetes (T1D) is a devastating autoimmune disease for which advanced mass spectrometry (MS) methods are increasingly used to identify new biomarkers and better understand underlying mechanisms. For example, integration of MS analysis and machine learning has identified multimolecular biomarker panels. In mechanistic studies, MS has contributed to the discovery of neoepitopes, and pathways involved in disease development and identifying therapeutic targets. However, challenges remain in understanding the role of tissue microenvironments, spatial heterogeneity, and environmental factors in disease pathogenesis. Recent advancements in MS, such as ultra-fast ion-mobility separations, and single-cell and spatial omics, can play a central role in addressing these challenges. Here, we review recent advancements in MS-based molecular measurements and their role in understanding T1D. [ABSTRACT FROM AUTHOR]

This paper studied the influence of storage duration on the flavor profile of white tea in detail, with samples produced between 2020 and 2023. Sensory evaluation was performed by quantitative descriptive analysis (QDA), followed by an in‐depth aroma components analysis employing an electronic nose (E‐nose), headspace gas chromatography–ion mobility spectrometry (HS–GC–IMS), and headspace solid–phase microextraction–gas chromatography–mass spectrometry (HS–SPME–GC–MS). The QDA findings revealed a gradual transition in the flavor profile of white tea during storage, shifting from sweet, fruity, and floral to more herbal and stale characteristics. E‐nose could well distinguish white tea with different storage times. A total of 55 and 53 volatile compounds were identified by HS–GC–IMS and HS–SPME–GC–MS, respectively. The orthogonal partial least squares‐discriminant analysis models, based on HS–GC–IMS (R2Y = 0.998, Q2 = 0.987) and HS–SPME–GC–MS (R2Y = 0.984, Q2 = 0.993), successfully distinguished white tea samples stored for different storage times. Furthermore, 14 and 8 key compounds were screened based on the double variable criterion of one‐way analysis of variance (p < 0.05) and variable importance in projection (VIP) >1.2, and their content changes were also compared. It is the gradual decrease of important aroma components such as 2‐hexenal, 2‐methyl‐2‐hepten‐6‐one, linalool, and geraniol, which are positively correlated with sweet, fruity, and floral aromas, and the gradual increase of hexanoic acid, thiophene, propanoic acid, dimethyl disulfide, and borneyl acetate, which are positively correlated with herbal and stale flavor, that leads to the changes in flavor and aroma of white tea during storage. The results of the study provided a reference for elucidating the aroma characteristics of white tea at different storage times as well as a theoretical basis for the quality control of white tea. [ABSTRACT FROM AUTHOR]

The objective of this study, PLASTOGEST, was to evaluate the risk associated with oligomers and other potentially harmful chemical compounds when consumed by humans through food. This research systematically reviewed existing literature and applies untargeted analysis to assess the fate of non‐intentionally added substances (NIAS) and intentionally added substances (IAS) during in vitro digestion. Polyethylene terephthalate and polybutylene terephthalate oligomers and simulation of real food conditions were used to evaluate migration and how these oligomers behave during in vitro digestion. This approach, involving enzymes and digestive juices, measured bioavailable levels of these substances in humans. The analytical work, including sample preparation was performed at Aarhus University, whilst extraction and untargeted analysis using ultra‐high performance liquid chromatography trap ion mobility spectroscopy time‐of‐flight mass spectrometry (UHPLC‐TIMS/TOF‐MS), were performed at Aristotle University of Thessaloniki. The EUFORA fellow gained insights into advanced analytical techniques and risk assessment, following specific EFSA guidelines. The study aimed to enhance our understanding on how plastic packaging materials might affect human health, potentially leading to more rigorous risk assessment frameworks. [ABSTRACT FROM AUTHOR]

Various techniques are available to illuminate geometric structures of molecular ions in gas phase, such as Förster Resonance Energy Transfer (FRET) informing on distances between two dyes covalently attached to a molecule. Typically, cationic rhodamines, which absorb and emit visible light, are used for labeling. Extensive work has revealed that the transition energy of a rhodamine is intricately linked to its nearby microenvironment, with nearby charges causing Stark‐shifted emission. This occurs because the inter‐dye Coulomb interaction is weaker in the excited state (S1) than in the ground state (S0) due to the increase in polarizability upon excitation. Therefore, absorption and emission spectra, along with FRET efficiencies, provide insights into structural motifs. At room temperature, multiple conformers often co‐exist, leading to overlapping absorption bands among different conformers and broad spectra. To study specific conformers, it is necessary to isolate them, for example, using ion‐mobility spectrometry. Another approach is to reduce temperature, which results in spectral narrowing and distinct absorption bands, allowing for the selection of specific conformers through selective excitation. Here, we describe the instrumentation used for cryogenically cold FRET experiments and discuss recent results for small model systems, as well as future directions for a technique still in its infancy. [ABSTRACT FROM AUTHOR]

A novel mixed-metal (Zn/Cd) metal–organic framework-based dispersive solid-phase microextraction (MM-MOFs-DSPME) method was developed for the efficient extraction of organophosphorus pesticides, diazinon and ethion, from various environmental matrices. The detection of the extracted analytes was performed using ion mobility spectrometry. The synthesized mixed-metal (Zn/Cd) MOF was characterized using a comprehensive array of analytical techniques: Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), and zeta potential measurement. This comprehensive characterization provided an in-depth understanding of the material's structural and functional properties. Key parameters influencing the efficiency of the dispersive solid-phase microextraction (DSPME) method were optimized, including pH, type of desorption solvent, buffer type and volume, sorbent amount, and adsorption and desorption time. Under these optimal conditions, the linear dynamic ranges obtained were 0.5 to 300 ng mL−1 for diazinon and 1.0 to 300 ng mL−1 for ethion, with limits of detection of 0.15 ng mL−1 and 0.29 ng mL−1, respectively. Preconcentration factors of 74% and 78%, with extraction recoveries of 98.4–104.2% and 96.6–103.4%, were achieved for diazinon and ethion, respectively. The relative standard deviations, calculated based on ten replicate measurements, yielded values of 3.8% for diazinon and 3.9% for ethion at a concentration of 10 ng mL−1, and 2.2% for diazinon, and 1.6% for ethion at a concentration of 150 ng mL−1, respectively. The developed method was successfully applied to the quantification of the target pesticides in soil, water, and apple samples. [ABSTRACT FROM AUTHOR]

Objective: Angiotensin-converting enzyme (ACE, EC 3.4.15.1) is a very important factor in the regulation of blood pressure. Also, the inhibition of ACE with natural compounds has been a very important research area in the treatment of high blood pressure. ACE was purified and characterized from sheep plasma. Molecular docking studies and the inhibition effect of thiamine, riboflavin, and captopril on ACE were investigated. Methods: Herein, ACE was purified from sheep plasma by affinity chromatography. The effect of thiamine and riboflavin on ACE was researched. Molecular docking studies were performed to understand the molecular interactions between thiamine, riboflavin, and captopril with ACE. Results: The purification coefficient was found to be 8636 fold. The binding energy of thiamine, riboflavin, and captopril was found to be -6.7 kcal/mol, -8.1 kcal/mol, and -5.5 kcal/mol, respectively. Thiamine conformed to three conventional hydrogen bonds with ASP:415, HIS:513, and LYS:454. Riboflavin formed four conventional hydrogen bonds with GLN:281, GLU:376, THR:282, and TYR:520. Captopril formed two conventional hydrogen bonds with ARG:124, one conventional hydrogen bond with TYR:62 and ASN:85, and one carbon-hydrogen bond with ASN:66. Molecular docking results showed that thiamine, riboflavin, and captopril interacted with ACE through hydrogen bonding and hydrophobic interactions. Thiamine and riboflavin indicated significant inhibition effects on ACE. The IC50 values of thiamine, riboflavin, and captopril were found as 960.56 µM, 11.02 µM, and 1.60 nM, respectively. Ki values for thiamine, riboflavin, and captopril were determined as 1352.04 µM, 12.30 µM, and 1.06 nM, respectively. Conclusion: In this work, it was concluded that thiamine and riboflavin may have preventive and therapeutical impacts against high blood pressure with their ACE inhibitor effect. Thiamine and riboflavin showed a lower inhibitory effect with a higher IC50 than captopril. However, when the inhibitory effect of thiamine and riboflavin vitamins is compared to captopril, it is concluded that they may be natural inhibitors with fewer side effects. [ABSTRACT FROM AUTHOR]

To investigate the optimum parameters of gas chromatography ion mobility spectrometry (GC-IMS) in determination of flavors and fragrances in tobacco. The effects of reaction parameters such as chromatographic column temperature, incubation temperature, incubation time and injection volume are evaluated with the number of identified characteristic peaks, peak intensity and peak pacing as indexes by an orthogonal L9 (34) test. Furthermore, prediction of test results is conducted based on the PLS method. Particle Swarm Optimization (PSO) is used to optimize the parameters. The collection of 30 different flavors and fragrances are tested by GC – IMS which operation parameters are set according to optimal results. The results show that a total of 60 kinds of the volatile organic compounds (VOCs) are identified across all samples, including aldehydes, ketones, alcohols, esters, ethers and so on. Therefore, by means of fingerprints can infer the general composition of fragrance-base or distinguish flavors and fragrances. [ABSTRACT FROM AUTHOR]

Introduction and objectives: The application of untargeted metabolomics assays using ultra high performance liquid chromatography-mass spectrometry (UHPLC-MS) to study metabolism in biological systems including humans is rapidly increasing. In some of these studies there is a requirement to collect and analyse low sample volumes of biofluids (e.g. tear fluid) or low cell and tissue mass samples (e.g. tissue needle biopsies). The application of microflow, capillary or nano liquid chromatography (≤ 1.0 mm column internal diameter (i.d.)) theoretically should accomplish a higher assay sensitivity compared to analytical liquid chromatography (2.1–5.0 mm column internal diameter). To date, there has been limited research into microflow UHPLC-MS assays that can be applied to study samples of low volume or mass. Methods: This paper presents three complementary UHPLC-MS assays (aqueous C18 reversed-phase, lipidomics C18 reversed-phase and Hydrophilic Interaction Liquid Chromatography (HILIC)) applying 1.0 mm internal diameter columns for untargeted metabolomics. Human plasma and urine samples were applied for the method development, with porcine plasma, urine and tear fluid used for method assessment. Data were collected and compared for columns of the same length, stationary phase and stationary phase particle size but with two different column internal diameters (2.1 mm and 1.0 mm). Results and conclusions: All three assays showed an increase in peak areas and peak widths when applying the 1.0 mm i.d. assays. HILIC assays provide an advantage at lower sample dilutions whereas for reversed phase (RP) assays there was no benefit added. This can be seen in the validation study where a much higher number of compounds were detected in the HILIC assay. RP assays were still appropriate for small volume samples with hundreds of compounds being detected. In summary, the 1.0 mm i.d. column assays are applicable for small volume samples where dilution is required during sample preparation. [ABSTRACT FROM AUTHOR]

Researches regarding quality control of ginseng focusing on the lipids are rare. Herein, ultra‐high‐performance supercritical fluid chromatography/ion mobility‐quadrupole time‐of‐flight mass spectrometry (UHPSFC/IM‐QTOF‐MS) combined with untargeted metabolomic analysis was utilized to holistically characterize and compare the lipidomic difference among 12 Panax‐derived herbal medicines. The established UHPSFC/IM‐QTOF‐MS method, using a Torus 1‐AA column with CO2/CH3OH (modifier) as the mobile phase, well resolved the ginseng lipidome within 30 min. The lipid isomers and those easily co‐eluted by conventional reversed‐phase chromatography got separated, and integrated analyses of the positive‐/negative‐mode MS data and IM‐derived collision cross section (CCS) greatly enhanced lipids identification. By the pattern recognition chemometric analysis of 90 batches of ginseng samples, the root ginseng samples showed significant differences in lipidome composition from those stem/leaf and flower samples. In contrast, red ginseng also contained lipids significantly different from the other root ginseng. Totally 82 potential differential lipids were discovered and identified based on the positive‐mode data and 90 ones in the negative mode. Some of these lipid markers might be diagnostic for their authentication. Conclusively, we first report the lipidomic difference among 12 ginseng varieties, and the information obtained can lay foundation for the accurate identification of ginseng from the lipidome level. [ABSTRACT FROM AUTHOR]

The visual authentication of high-value truffles (Tuber magnatum and Tuber melanosporum) is challenging, as they share similar morphological characteristics with other truffle species that have a lower economic value. This similarity complicates accurate identification and increases the risk of substitution or mislabeling, which can affect both market prices and consumer trust. For this reason, the aim of this study was to apply a non-targeted lipidomic approach using ion mobility spectrometry-mass spectrometry to distinguish between white (T. magnatum, Tuber borchii, and Tuber oligospermum) and black truffle species (T. melanosprum, T. aestivum, T. aestivum var. uncinatum, T. brumale, and T. indicum) and to determine the different geographical origins of the two most valuable truffle species (T. melanosporum and T. magnatum). Among several hundred features, 37 and 57 lipids were identified as marker compounds to distinguish white and black truffle species using MS/MS spectra and collision cross section (CCS) values, respectively. Only a few marker compounds were necessary to recognize the differences between white and black truffles. In particular, ceramides, glycerolipids, and phospholipids proved to be particularly suitable for separating the species. In addition, different metabolite profiles were determined for T. melanosporum and T. magnatum depending on their geographical origin. These findings lay the groundwork for a comprehensive quality control framework for fresh truffles, ensuring authenticity, detecting adulteration, and preserving their premium status. [ABSTRACT FROM AUTHOR]

Southern Shaanxi is one of China's high-quality congou black tea production areas. However, the differences in geography, cultivation, and management techniques and production processes lead to uneven qualities of southern Shaanxi congou black tea in different production areas. This study used sensory analysis combined with gas chromatography–ion mobility spectrometry (GC-IMS) to determine southern Shaanxi congou black teas' geographical origin and volatile fingerprints to prevent economic losses caused by fraudulent labeling. A total of 61 volatile compounds were identified and quantified by GC-IMS. Three main aroma types were found by sensory analysis coupled with significant difference analysis, and a clear correlation between volatile compounds, aroma type, and geographical origin was found by sensory and gallery plot analysis. The black tea with a green/grassy-roast aroma type was mainly distributed in production areas with an altitude of 400–800 m and 1-pentanol, cyclohexanone, 1-penten-3-one, 2-heptanone, dihydroactinidiolide and butyrolactone were the key aroma markers. The black teas produced in production areas with an altitude of 800–1000 m mainly presented strong honey and caramel-like aromas, and sotolone, furaneol, and phenylacetaldehyde played an important role. These results will be helpful for discriminating black tea from different tea production areas in southern Shaanxi. [ABSTRACT FROM AUTHOR]

Plasma medicine is a field that utilizes reactive species generated from atmospheric low-temperature plasmas for applications such as sterilization, blood coagulation, and cancer therapy. Commercial plasma devices are available for wound healing, but research on the chemical modifications induced by these plasmas is scarce. This study explores the chemical modifications in hemoglobin when exposed to a helium plasma dielectric barrier discharge, with the aim of explaining the potential mechanisms through which it contributes to blood coagulation and enhances wound healing. Optical microscopy of cold atmospheric plasma (CAP) treated whole capillary blood showed an increase in red blood cell (RBC) size and the formation of rouleaux structures. The treatment of whole blood leads to hemolysis of RBCs and the release of intracellular protein content. We then treated purified hemoglobin protein at physiological concentrations, which led to the formation of aggregates that could be observed using ion mobility mass spectrometry (IM–MS), size exclusion chromatography, and optical microscopy. The aggregates formed fibril-like structures as observed using atomic force microscopy. The formation of hemoglobin aggregates is hypothesized to be the result of new intermolecular interactions formed following the CAP-mediated protein oxidation. We studied the changes to hemoglobin structure after treatment with a CAP using high-resolution MS and found that the hemoglobin subunits are oxidized with the addition of at least 4 oxygen atoms each. The intact tetrameric hemoglobin structure remains unchanged; however, the monomeric and dimeric proteins adopt a more compact structure, as observed by IM–MS. We propose that CAP treatment of fresh blood leads to hemolysis, and that the extracellular protein, primarily hemoglobin, is oxidized leading to the formation of aggregates. [ABSTRACT FROM AUTHOR]

Low-temperature plasma (LTP) jets are Food and Drug Administration (FDA)-approved medical devices to remove cancerous tissue and aid in wound healing. However, reports on their reaction with proteins are conflicting, ranging from fragmentation, oxidation, aggregation, or a combination thereof. In this study we bridge the gap between plasma-treatment of short peptides to proteins at physiologically relevant concentrations. The LTP in this study is based on a helium dielectric barrier discharge that forms a plasma-jet, which is directed at the solution without direct contact with the plasma, and results in the formation of reactive oxygen species (ROS) OH• and O2•− in solution. The longer the solution is treated, the more solution-phase ROS form. Treating peptide- and protein-containing solutions leads to extensive oxidation. The ROS led to the same oxidative modifications for peptide M with increasing chain length (9, 18, 37, 76 amino acids), which could be identified with high-resolution mass spectrometry. Oxidized species M + x O led to conformational changes such as compaction and elongation, while the unmodified peptide M remained unaltered, as found by ion mobility spectrometry and size exclusion chromatography. For proteins at high concentration, insoluble aggregates formed and could be identified by UV/V is light scattering and atomic force microscopy. The formation of aggregates is dependent on the amino acid chain length, the peptide concentration, and the time for aggregate formation. These findings highlight the importance of both peptide chain length and concentration in determining the fate of peptides following the exposure to LTP, while also offering valuable insights for the field of plasma medicine. [ABSTRACT FROM AUTHOR]

Positive-ion laser desorption/ionization (LDI) of fullerenes contained in soot as produced by the Krätschmer-Huffman process delivers a wide range of fullerene molecular ions from C56+• to above C300+•. Here, the collision cross section (CCS) values of those fullerene molecular ions are determined using a trapped ion mobility-quadrupole-time-of-flight (TIMS-Q-TOF) instrument. While CCS values in the range from C60+• to C96+• are already known with high accuracy, those of ions from C98+• onward had yet to be determined. The fullerene molecular ions covered in this work have CCS values from about 200 to 440 Å2. The fullerene molecular ion series is evenly spaced at C2 differences in composition, and thus, small CCS differences of just 2.2–3.5 Å2 were determined across the entire range. Fullerene M+• ions may be employed as mobility calibrants, in particular, when very narrow 1/K0 ranges are being analyzed to achieve high TIMS resolving power. In addition, due to the simple elemental composition, M+• ions of fullerenes could also serve for mass calibration. This study describes the determination of CCS values of fullerene molecular ions from C56+• to C240+• and the application of ions from C56+• to C220+• to calibrate the ion mobility scale of a Bruker timsTOFflex instrument in any combination of LDI, matrix-assisted laser desorption/ionization (MALDI), and electrospray ionization (ESI) modes in the CCS range from about 200 to 420 Å2. This use was exemplified along with ions from Agilent Tune Mix, leucine-enkephalin, angiotensin I, angiotensin II, and substance P. [ABSTRACT FROM AUTHOR]

Bile acid (BA) is one of the main active components of bile and has multiple isomers, the structure or content of its isomers often changes due to diseases and other health problems; thus, the accurate detection of BA isomers is very important. In this study, two groups of BA isomers of glycine-conjugated BAs and taurine-conjugated BAs were simultaneously separated and quantitatively analyzed by ion mobility mass spectrometry (IM-MS). Especially, baseline mobility separation between the isomers was achieved by the formation of binary complexes via simple interaction with spiramycin (SPM), for which a separation resolution (Rp-p) of 1.96 was reached. Moreover, BA isomers were quantitatively analyzed, and the limit of detection (LOD) of absolute quantification for TCDCA/TUDCA and GUDCA/GCDCA/GHDCA was 0.514 and 0.611 ng∙mL−1, respectively; the LODs for molar ratio ranges of relative quantification for TCDCA/TUDCA, GUDCA/GHDCA, and GCDCA/GHDCA were 1:18–30:1, 1:18–21:1, and 1:19–21:1, respectively. Additionally, BA isomers analyzed in pig bile powder and bear bile powder were measured, which were in good consistency with those labeled, revealing the differences in BA composition and content between the two powders. Finally, BA detection and recovery analyses were performed on serum samples, with a recovery rate of ≥73.69%, RSD of ≤6.8%, and SR (standard deviation of recoveries, the degree of difference between measured values and average recovery) of ≤1.27. Due to the simple, rapid, and lack of need for complex sample preparation and chromatographic separation, the proposed method can be an effective method for BA detection in practical samples. [ABSTRACT FROM AUTHOR]

Non-steroidal anti-inflammatory drugs (NSAID) are not recommended for use against pneumonia in humans, but are commonly utilised against bovine respiratory disease. This study aimed to determine if the use of NSAIDs in the early phase of bovine respiratory syncytial virus (BRSV)-infection limits pulmonary inflammation. Four to nine-week old calves were infected with BRSV by aerosol and were treated with either meloxicam intravenously on day (D)4 (n = 5, MEL), acetylsalicylat-DL-lysin intravenously on D4 and D5 (n = 5, ASA), or were left untreated as controls (n = 5, CTR). Clinical signs were monitored daily until necropsy on D7, BRSV-RNA was detected in nasal swabs and bronchoalveolar lavage (BAL) by RT-qPCR, inflammatory cells and proteins were identified in BAL by cytology and label-free quantitative mass spectrometry-based proteomics, respectively, and oxylipids were quantified in BAL and plasma by liquid chromatography tandem mass spectrometry with triple quadrupole mass detectors. The calves developed mild to moderate signs of respiratory disease and, with the exception of one MEL-treated and one ASA-treated calf, limited lung lesions. None of the treatments had a significant effect on virus replication, clinical signs or lung lesion extent. Relative to controls, both treatments initially induced a downregulation of proteins in BAL. Immunoglobulin (Ig)-related proteins, such as the Ig kappa and lambda locus and the joining chain of IgA and IgM, were downregulated in MEL-treated calves compared to controls. In addition, meloxicam induced an increased neutrophil influx in BAL in response to BRSV, possibly related to a reduction in plasma prostaglandin, and to a downregulation of The Liver X Receptor/ Retinoid X Receptor (LXR/RXR), the Farnesoid X Receptor (FXR)/RXR and the 24-Dehydrocholesterol Reductase (DHC24) signalling pathways in the lung. The risk of NSAIDs to increase neutrophil activity during stimulation with BRSV or other toll-like receptor 4 agonists needs to be investigated further. Since augmented neutrophil responses can be detrimental, the results of the present study do not support the use of NSAIDs to prevent the clinical expression of BRSV-infection. [ABSTRACT FROM AUTHOR]

Flavor is an important indicator of the edible quality of fresh corn. In order to explore the composition and content differences of volatile flavor compounds in different types of fresh corn, in this study, 6 different types of fresh corn varieties including NKN 323 were used as materials, and electronic nose technology and gas chromatography ion mobility spectrometry (GC-IMS) technology were used to detect the volatile flavor compounds in fresh corn to evaluate the contribution of volatile flavor compounds to the overall flavor of fresh corn by relative odor activity value (ROAV) . The results showed that a total of 34 volatile flavor compounds were identified, including 10 esters (34.68%~26.74%), 8 aldehydes (28.46%~21.22%), 6 alcohols (10.33%~6.04%), 5 ketones (14.74%~9.87%), 2 ethers (10.05%~6.94%) and 3 other compounds. GC-IMS fingerprints showed that the difference of volatile flavor compounds content important which caused the difference of characteristic flavor of different types of fresh corn. 5 common key aroma components and 23 different characteristic flavor compounds of fresh corn were identified by ROAV. The total release of volatile flavor compounds of different types of varieties was NKN323, followed by JKT608. Isovaleraldehyde contributed the most to the overall flavor of NKN336, JZN219, JKN768 and JKT608, while 3- octanone contributed the most to the overall flavor of NKN323 and JKN2000. Above results provided theoretical basis for the analysis and evaluation of volatile flavor compounds in fresh corn and the precise control of characteristic flavor. [ABSTRACT FROM AUTHOR]

The subtle structural variations among carbohydrate isomers pose significant challenges for their identification and quantification. Here, we propose a strategy for rapid identification and quantification of isomeric disaccharides via derivatization with 4-(3-methyl-5-oxo-pyrazolin-1-yl) benzoic acid (CPMP) and analysing by ion mobility spectrometry (IMS). After derivatization, the ionization efficiency of disaccharides was significantly improved. The disaccharide isomers were distinguished by determining the different ion mobilities of CPMP-labelled disaccharides. Among them, [M + 2CPMP + H]+ was separated with a resolution of 1.484, almost achieving baseline separation. Subsequently, [M + CPMP + Na]+ was used for the relative quantification of lactose and maltose, showing a good linear relationship with R2 > 0.990. Finally, the method was successfully applied to the identification of lactose and maltose in beer and milk. The method is fast, accurate and effective for the identification of disaccharide isomers in complex samples. [ABSTRACT FROM AUTHOR]

The document from the journal "Analyst" published by The Royal Society of Chemistry in 2024 provides a comprehensive list of research papers and articles on various topics related to chemistry. The papers cover a wide range of subjects, including electrochemical approaches for biomarker detection, detection of volatile organic compounds, catalytic kinetics, and sensor development for various applications. The journal aims to connect the global chemistry community through impactful research and publications, reinvesting profits back into the field. [Extracted from the article]

We consider the setting of multiscale overdamped Langevin stochastic differential equations, and study the problem of learning the drift function of the homogenized dynamics from continuous-time observations of the multiscale system. We decompose the drift term in a truncated series of basis functions, and employ the stochastic gradient descent in continuous time to infer the coefficients of the expansion. Due to the incompatibility between the multiscale data and the homogenized model, the estimator alone is not able to reconstruct the exact drift. We therefore propose to filter the original trajectory through appropriate kernels and include filtered data in the stochastic differential equation for the estimator, which indeed solves the misspecification issue. Several numerical experiments highlight the accuracy of our approach. Moreover, we show theoretically in a simplified framework the asymptotic unbiasedness of our estimator in the limit of infinite data and when the multiscale parameter describing the fastest scale vanishes. [ABSTRACT FROM AUTHOR]

Ion mobility‐mass spectrometry (IM‐MS) has recently contributed to the structural analysis of molecules, including supramolecules and proteins, by determining the ion arrival time distributions correlated with the collision cross sections (CCSs), as well as the mass‐to‐charge ratios. However, its application range is still limited owing to the lack of general CCSs simulation methods based on possible molecular conformations. Here, a molecular dynamics‐based conformational search method for simulating CCS distributions using projection approximation is reported. As a case study, the gas‐phase conformations of the sodium adducts of conformationally flexible polyketones with 3,3‐dimethylpentane‐2,4‐dione as the monomer are analyzed. The sodium adduct of the hexamer (m/z 781.4 for [1 + Na]+) showed a monomodal arrival time distribution, but that of the octamer sodium adduct (m/z 1033.5 for [2 + Na]+) is multimodal. The conformational analysis indicated an unimodal CCS distribution of simulated [1 + Na]+ conformations in which the sodium cation is mainly bound at the chain terminal. Conversely, four clusters of conformations are obtained for [2 + Na]+ based on the Na+‐coordination sites, which qualitatively reproduced the observed CCS distribution. This approach will extend the utility of IM‐MS for the conformational analysis of flexible molecules in the gas phase. [ABSTRACT FROM AUTHOR]

In the present study, a modified carbon nano-onion and β–cyclodextrin composite was utilized in micro-solid phase extraction of atenolol and metoprolol from human plasma samples. The synthesized sorbent structure and morphology were evaluated. In this method, a proper amount of the sorbent was contacted with the diluted plasma sample under vortexing (to promote the sorbent contact area with the solution). The separated particles by centrifugation were contacted with a proper eluent to desorb the target analytes. After that, the eluent was separated by centrifugation and used during analysis of the analytes by high-performance liquid chromatograph. Several effective extraction parameters such as the sorbent amount, type and elution solvent volume, and extraction time were evaluated and optimized. The validated factors showed that detection and quantification were 0.09 and 0.01 and 0.29 and 0.03 ng mL–1, for metoprolol and atenolol, respectively. The method precision, considered as relative standard deviation, was ≤ 2.5 and ≤ 3.6% for intra- (n = 5) and inter-day (n = 4) precisions, respectively. The extraction recovery values were obtained 84 and 63% for metoprolol and atenolol, respectively. Lastly, the developed method was utilized successfully on the plasma samples of patients treated with metoprolol and atenolol. [ABSTRACT FROM AUTHOR]