Spectral Comparison Research Articles

Spectral analysis comparison of pushbroom and snapshot hyperspectral cameras for in vivo brain tissues and chromophore identification.

Hyperspectral imaging sensors have rapidly advanced, aiding in tumor diagnostics for in vivo brain tumors. Linescan cameras effectively distinguish between pathological and healthy tissue, whereas snapshot cameras offer a potential alternative to reduce acquisition time. Our research compares linescan and snapshot hyperspectral cameras for in vivo brain tissues and chromophore identification. We compared a linescan pushbroom camera and a snapshot camera using images from 10 patients with various pathologies. Objective comparisons were made using unnormalized and normalized data for healthy and pathological tissues. We utilized the interquartile range (IQR) for the spectral angle mapping (SAM), the goodness-of-fit coefficient (GFC), and the root mean square error (RMSE) within the 659.95 to 951.42nm range. In addition, we assessed the ability of both cameras to capture tissue chromophores by analyzing absorbance from reflectance information. The SAM metric indicates reduced dispersion and high similarity between cameras for pathological samples, with a 9.68% IQR for normalized data compared with 2.38% for unnormalized data. This pattern is consistent across GFC and RMSE metrics, regardless of tissue type. Moreover, both cameras could identify absorption peaks of certain chromophores. For instance, using the absorbance measurements of the linescan camera, we obtained SAM values below 0.235 for four peaks, regardless of the tissue and type of data under inspection. These peaks are one for cytochrome b in its oxidized form at , two for at and , and one for water at . The spectral signatures of the cameras show more similarity with unnormalized data, likely due to snapshot sensor noise, resulting in noisier signatures post-normalization. Comparisons in this study suggest that snapshot cameras might be viable alternatives to linescan cameras for real-time brain tissue identification.

Cytotoxic Effects of Oleanane-type Saponins from Lysimachia laxa.

Phytochemical investigation of the methanol extract of the aerial parts of Lysimachia laxa led to the isolation of four new oleanane-type saponins, lysimosides A-D (1-4) and one known compound, lysimachigenoside B (5). Their structures were elucidated using a combination of HR-ESI-MS, 1D and 2D-NMR spectral data, chemical methods, and comparison with previous literature. The cytotoxic activity of these compounds was evaluated against human lung cancer (A-549) and human breast cancer (MCF-7) cell lines. All compounds exhibited cytotoxic activity against A-549 and MCF-7 cell lines with IC50 values ranging from 6.1 to 16.0 µM, comparable to the positive control, mitoxantrone. Interestingly, oleanane-type saponins with an acetyl group (2-4) exhibited increased cytotoxic activities compared to those without an acetyl group (1).

A novel methodology for gamma-ray spectra dataset procurement over varying standoff distances and source activities

The adoption of machine learning approaches for gamma-ray spectroscopy has received considerable attention in the literature. Many studies have investigated the deployment of various algorithm architectures to a specific task. However, little attention has been afforded to the development of the datasets leveraged to train the models. Such training datasets typically span a set of environmental or detector parameters to encompass a problem space of interest to a user. Variations in these measurement parameters will also induce fluctuations in the detector response, including expected pile-up and ground scatter effects. Fundamental to this work is the understanding that 1) the underlying spectral shape varies as the measurement parameters change and 2) the statistical uncertainties associated with two spectra impact their level of similarity. While previous studies attribute some arbitrary discretization to the measurement parameters for the generation of their synthetic training data, this work introduces a principled methodology for efficient spectral-based discretization of a problem space. A signal-to-noise ratio (SNR) respective spectral comparison measure and a Gaussian Process Regression (GPR) model are used to predict the spectral similarity across a range of measurement parameters. This innovative approach effectively showcased its capability by dividing a problem space, ranging from 5 cm to 100 cm standoff distances and 5 μCi–100 μCi of 137Cs, into three unique combinations of measurement parameters. The findings from this work will aid in creating more robust datasets, which incorporate many possible measurement scenarios, reduce the number of required experimental test set measurements, and possibly enable experimental training data collection for gamma-ray spectroscopy.

Synthesis of (oxo)chlorin dimers chelated with thallium(III)

Two target dimers have been prepared for fundamental studies of hole/electron transfer. Metalation with thallium(III) enables clocking of the rate of hole/electron transfer between the two macrocycles. Each dimer contains a diphenylethyne linker joining two identical hydroporphyrins (chlorin or oxochlorin). The linker is substituted at the 4,4′-positions whereas each (oxo)chlorin is joined at the 10-position. Each (oxo)chlorin is equipped with a gem-dimethyl group at the 18-position to stabilize the hydroporphyrin chromophore toward adventitious dehydrogenation and a 3,5-di-tert-butyl group at the 5-position to achieve increased solubilization in organic media. The dimers parallel a prior set of diphenylethyne-linked (oxo)chlorin constructs containing zinc-free base, zinc-zinc, and copper-copper metalation states that have been examined in studies of electronic communication. The building block (oxo)chlorins for preparing the thallium-containing dimers have been prepared in quantities of 32–404 mg, a scale up to 14-fold larger than previously. Thallation of the free base (oxo)chlorin dimers was achieved with excess TlCl3⋅4H2O in CH2Cl2/CH3OH (3–4:1) upon overnight reaction at room temperature. The long-wavelength (Q[Formula: see text] absorption band of (oxo)chlorins lies between that of the zinc(II) and free base counterparts. Absorption spectral comparisons are provided of the thallium(III) and free base (oxo)chlorin monomers and dimers.

Synthesis of porphyrin triads chelated with thallium(III) for studies of ground-state hole/electron transfer

Four target all-porphyrin triads have been prepared for fundamental studies of ground-state hole/electron transfer. Each triad contains thallium(III) porphyrins as bookends, which bear mesityl groups at the three non-linking meso-positions. The central porphyrin is a free base or thallium(III) porphyrin bearing mesityl or pentafluorophenyl groups at the two non-linking meso-positions. The linker is a 4,4′-diphenylethyne unit joined at the porphyrin meso-positions. The net spacer between the two bookend thallium(III) porphyrins thus consists of diphenylethyne–porphyrin–diphenylethyne and is designed as a superexchange element for through-bond hole/electron transfer. The energetics of the superexchange element are tunable given the nature of the substituents and metalation state of the central porphyrin. The synthesis entailed Sonogashira coupling of two building blocks, a free base bis(4-iodophenyl)porphyrin and a mono-ethynylporphinato thallium(III) chloride. Two benchmark porphyrins also were prepared. Absorption spectral comparisons are provided including of the all-thallium(III) monomer, dimer, and triad.

Cosmic pears from the Havelland (Germany): Ribbeck, the twelfth recorded aubrite fall in history

AbstractIn 1889 the German poet and novelist Theodor Fontane wrote the popular literary ballad “Herr von Ribbeck auf Ribbeck im Havelland.” The Squire von Ribbeck is described as a gentle and generous person, who often gives away pears from his pear trees to children passing by and continued donating pears after his death. Now, 135 years later the rock called Ribbeck is giving us insight into processes that happened 4.5 billion years ago. The meteorite Ribbeck (official find location: 52°37′15″N, 12°45′40″E) fell January 21, 2024, and has been classified as a brecciated aubrite. This meteoroid actually entered the Earth's atmosphere at 00:32:38 UTC over Brandenburg, west of Berlin, and the corresponding fireball was recorded by professional all sky and video cameras. More than 200 pieces (two proved by radionuclide analysis to belong to this fresh fall) were recovered totaling about 1.8 kg. Long‐lived radionuclide and noble gas data are consistent with long cosmic ray exposure (55–62 Ma) and a preatmospheric radius of Ribbeck between 20 and 30 cm. The heavily brecciated aubrite consists of major (76 ± 3 vol%) coarse‐grained FeO‐free enstatite (En99.1Fs<0.04Wo0.9), with a significant abundance (15.0 ± 2.5 vol%) of albitic plagioclase (Ab95.3 An2.0Or2.7), minor forsterite (5.5 ± 1.5 vol%; Fo99.9) and 3.5 ± 1.0 vol% of opaque phases (mainly sulfides and metals) with traces of nearly FeO‐free diopside (En53.2Wo46.8) and K‐feldspar (Ab4.6Or95.4). The rock has a shock degree of S3 (U‐S3), and terrestrial weathering has affected metals and sulfides, resulting in the brownish appearance of rock pieces and the partial destruction of certain sulfides already within days after the fall. The bulk chemical data confirm the feldspar‐bearing aubritic composition. Ribbeck is closely related to the aubrite Bishopville. Ribbeck does not contain solar wind implanted gases and is a fragmental breccia. Concerning the Ti‐ and O‐isotope compositions, the data are similar to those of other aubrites. They are also similar to E chondrites and fall close to the data point for the bulk silicate Earth (BSE). Before the Ribbeck meteoroid entered Earth's atmosphere, it was observed in space as asteroid 2024 BX1. The aphelion distance of 2024 BX1's orbit lies in the innermost region of the asteroid belt, which is populated by the Hungaria family of minor planets characterized by their E/X‐type taxonomy and considered as the likely source of aubrites. The spectral comparison of an average large‐scale emission spectrum of Mercury converted into reflectance and of the Ribbeck meteorite spectrum does not show any meaningful similarities.

Robustanic acid as a glutaminase and Na+, K+-ATPase inhibitor from leaves of Eucalyptus globulus.

This study was to compare glutaminase and Na+, K+-ATPase inhibitory activities of 20 herbal extracts and investigate the isolation, structural elucidation and those inhibitory activities of three triterpenes from the selected extract of Eucalyptus globulus Labill. Three triterpenes, ursolic acid (1), robustanic acid (2) and ursolic acid lactone (3), were identified by analyzing their NMR and MS spectral data and comparison of these with reported data. The IC50 values of 1-3 and the control compound against glutaminase, 6-diazo-5-oxo-l-norleucine (DON), were 443 μM, 334 μM, 963 μM and 134 μM, respectively. The IC50 values of 1, 2 and the control compound against Na+, K+-ATPase and ouabain, were 180 μM, 56 μM and 0.5 μM, respectively. Compounds 1 and 2 may serve as potential lead compounds for the prevention and treatment of neurodegenerative and lifestyle-related diseases by targeting glutaminase and Na+, K+-ATPase. This is the first report on glutaminase and Na+, K+-ATPase inhibitory activities of 2.

Some spectral comparison results on infinite quantum graphs

In this paper we establish spectral comparison results for Schrödinger operators on a certain class of infinite quantum graphs, using recent results obtained in the finite setting. We also show that new features do appear on infinite quantum graphs such as a modified local Weyl law. In this sense, we regard this paper as a starting point for a more thorough investigation of spectral comparison results on more general infinite metric graphs.

Characterizing leaf-deposited particles: Single-particle mass spectral analysis and comparison with naturally fallen particles

The size and composition of particulate matter (PM) are pivotal in determining its adverse health effects. It is important to understand PM's retention by plants to facilitate its atmospheric removal. However, the distinctions between the size and composition of naturally fallen PM (NFPM) and leaf-deposited PM (LDPM) are not well-documented. Here we utilize a single-particle aerosol mass spectrometer, coupled with a PM resuspension chamber, to analyze these differences. We find that LDPM particles are 6.8–97.3% larger than NFPM. Employing a neural network algorithm based on adaptive resonance theory, we have identified distinct compositional profiles: NFPM predominantly consists of organic carbon (OC; 31.2%) and potassium-rich components (19.1%), whereas LDPM are largely composed of crustal species (53.9–60.6%). Interestingly, coniferous species retain higher OC content (11.5–13.7%) compared to broad-leaved species (0.5–1.2%), while the levoglucosan content exhibit an opposite trend. Our study highlights the active role of tree leaves in modifying PM composition beyond mere passive capture, advocating for a strategic approach to species selection in urban greening initiatives to enhance PM mitigation. These insights provide guidance for urban planners and environmentalists in implementing nature-based solutions to improve urban air quality.

Extended X-ray Absorption Fine Structure (EXAFS) Measurements on Alkali Metal Superatoms of Ta-Atom-Encapsulated Si16 Cage.

The silicon cage nanoclusters encapsulating a tantalum atom, termed Ta@Si16, exhibit characteristics of alkali metal "superatoms (SAs)". Despite this conceptual framework, the precise structures of Ta@Si16 and Ta@Si16+ remain unclear in quantum calculations due to three energetically close structural isomers: C3v, Td, and D4d structures. To identify the geometrical structure of Ta@Si16 SAs, structural analysis was conducted using extended X-ray absorption fine structure (EXAFS) with a high-intensity monochromatic X-ray source, keeping anaerobic conditions. Focusing on "superordered" films, which constitute amorphous thin films composed solely of Ta@Si16 SAs, this analysis preserved locally ordered structures. Spectral comparisons between experimental and simulated Ta L3-edge EXAFS unveil that Ta@Si16 SAs on a substrate adopt a C3v-derived structure, while Si K-edge EXAFS introduces spectral ambiguity in structural identifications, attributed to both intracluster and intercluster scatterings. These findings underscore the significance of locally ordered structure analyses in understanding and characterizing novel nanoscale materials.

Investigation of pyruvic acid photolysis at the air-liquid interface as a source of aqueous secondary organic aerosols

Pyruvic acid (PA) is a ubiquitous 2-oxocarboxylic acid in the atmosphere. Its photochemical process at the air-liquid (a-l) interface has been suggested as an important source of aqueous secondary organic aerosols. We investigated the photochemical reaction pathways of PA at the a-l interface using synchrotron-based vacuum ultraviolet single-photon ionization mass spectrometry (VUV SPI-MS) coupled with the System for Analysis at the Liquid Vacuum Interface (SALVI) microreactor. Results from mass spectral analysis and the determination of appearance energies (AEs) indicate that photolysis of PA can generate radicals, then they recombine with carboxylic acids and simple molecular oligomers. Furthermore, the preliminary products could form larger oligomers via radical reaction or esterification in the presence of hydroxyl and carboxyl functional groups. Mass spectral comparison shows that most photochemical reactions would complete within 4 h. The expanded photochemistry-driven reaction flowchart of PA is proposed based on the newly discovered products. Our results reveal that the interfacial PA photochemical reactions have different mechanisms from the bulk liquid due to the interfacial properties, such as molecular density, composition, and ion concentration. Our findings show that in situ mass spectral analysis with bright photon ionization is useful to elucidate the contribution of a-l interfacial reactions leading to aqSOA formation.

ISOLATION AND CHARACTERIZATION OF CYCLOEUCALENOL TRANSFERULATE FROM LEAVES OF Euphorbia tithymaloides

The latex, leaves, stems, and roots of Euphorbia tithymaloides (Euphorbiaceae) have traditionally been used to treat earaches, insect stings, ringworm, toothaches, skin cancer, umbilical hernia, and warts. Approximately 1 kg of the pulverized leaves was macerated successively with hexane and ethyl acetate, and resultant Crude extracts were phytochemically screened using standard established procedures. Ethyl acetate extract was loaded onto a column containing slurry of silica gel. Gradients of hexane in ethyl acetate mobile phase were used to elute the column, affording a total of 130 fractions. Fractions 41-47 gave tiny deposit on evaporation labelled UMPT (m.p: 269-270 oC).Their thin layer chromatography gave a single spot of Rf 0.61.These were combined and labelled UMPT44. Phytochemical screening of UMPT44 gave positive test for phenols and triterpenoids. Antimicrobial screening of UMPT44 showed that it was active against some fungi and bacteria. The zone of inhibition measured 30 mm when tested against Coniophora puteana, 29 mm against methicillin-resistant Staphylococcus aureus, 27 mm against Salmonella typhi, and 26 mm against Staphylococcus aureus, Fusarium oxysporum, and Escherichia coli. Additionally, there was a 25 mm zone of inhibition against Serpula lacrymans. The determination of minimum inhibitory concentration and minimum bactericidal/fungicidal concentration indicated that UMPT44 holds promise as a potential antimicrobial agent. Based on evaluation of NMR spectral data and comparison with literature reports, UMPT44 was identified as cycloeucalenol transferulate. This is the first time this compound is isolated from the plant

Dual-Channel Imine-Amine Photoisomerization in a Benzoimidazole and Benzothiazole Coupled System: Photophysics and Applications.

A molecule, namely 2-(1H-benzo[d]imidazol-2-yl)-6-(benzo[d]thiazol-2-yl)-4-bromophenol (BIBTB), having a two-way proton transfer unit of thiazole and imidazole moieties was synthesized and characterized by NMR, electrospray ionization mass spectrometry (ESI-MS), and single-crystal diffraction studies. Steady state and time-resolved spectral studies of BIBTB support excited state intramolecular proton transfer (ESIPT), causing imine-amine tautomerization through a two-way 6-membered H-bonded ring, where the N atoms of benzothiazole and the benzoimidazole unit are involved as proton acceptor sites. Interestingly, in a nonpolar and moderately polar solvent, photoisomerization in BIBTB is found to be favored toward the thiazole ring, whereas in a highly polar solvent, it is favored toward the imidazole ring. A spectral comparison of BIBTB with judicially designed molecules 2-(benzo[d]thiazol-2-yl)-4-bromophenol (HBT) and 2-(1H-benzo[d]imidazol-2-yl)-4-bromophenol (BIB) supports these inferences. Theoretical calculation using the Density Functional Theory (DFT) at CAM-B3LYP/6-311+G(d,p) level supports the existence of two low-energy 6-membered hydrogen-bonded planar conformers in the ground state in the gas phase and in solvents of different dielectrics. The potential energy curves (PECs) calculated along the proton transfer (PT) coordinate are found to have a high energy barrier in the ground state and to be barrierless or have a low energy barrier in the excited state for both the forms. The calculated vertical excitation and the emission energy from the relaxed excited and PT states show good correlation with the experimental spectral data. Aggregation of BIBTB in water with red shifted emission was established from X-ray single-crystal structure analysis, solid state emission, and Dynamic Light Scattering (DLS) measurement. The molecule BIBTB also acts as a fluorescence probe for sensing the explosive picric acid in the subnano scale and can be used to determine the proportion of water in dimethyl sulfoxide (DMSO) solvent.

Land Use Sustainability: Assessment of the Dynamic Response of Typical Bedrock-Buried-Hill Earth Fissure Sites in the Su-Xi-Chang Area

Disaster prevention and the mitigation of earth fissures is a key issue in the sustainable development of urban land. Structures directly avoiding earth fissures are not conducive to the rational planning and efficient utilization of urban construction. The Su-Xi-Chang area, which consists of the cities of Suzhou, Wuxi, and Changzhou, surrounded by Taihu Lake, has developed bedrock buried-hill earth fissures that are rare in the rest of the country. Existing research results have identified the genesis mechanisms, distribution patterns, and developmental characteristics of this type of fissure. Not only does the slow-variable activity of earth fissures cause direct damage to surface and underground structures, but in addition, when an earthquake occurs, the presence of earth fissures may cause the seismic response of the site to be altered or even strengthened, leading to unknown damage or the possible destruction of structures near the fissures. However, no studies have been conducted to assess the dynamic effects of bedrock-buried-hill earth fissure sites. Therefore, in this research, based on six typical bedrock-buried-hill-type earth fissures in the Su-Xi-Chang area, and in order to accurately reveal the dynamic amplification effect law of the earth fissure sites, systematic spectral analyses and comparisons of the microtremor signals were carried out by using the linear analysis method (Direct Fourier Transform Analysis) and the nonlinear analysis method (Hilbert–Huang Transform). The results show that bedrock-buried-hill-type earth fissures have a significant amplification effect on the dynamic response of the site; the amplification effect of bedrock-buried-hill fissure sites follows the same attenuation pattern, and the furthest range of the dynamic response on the site is about 25 m, beyond which the original seismic fortification level can be maintained; the extreme value of the amplification factor of the two sides of this type of site, as derived from the Fourier and HHT methods, is about double, and the nearest earth fissure region should be considered to have a raised seismic fortification intensity of more than double the original. The Hilbert–Huang transform method has good applicability for processing microtremor data, and nonlinear signal analysis methods can be considered comprehensive for future microtremor signal processing.

Detectability of Supermassive Dark Stars with the Roman Space Telescope

Supermassive dark stars (SMDS) are luminous stellar objects formed in the early Universe at redshift z ∼ 10–20, made primarily of hydrogen and helium, yet powered by dark matter. We examine the capabilities of the Roman Space Telescope (RST), and find it able to identify ∼106 M ⊙ SMDSs at redshifts up to z ≃ 14. With a gravitational lensing factor of μ ∼ 100, RST could identify SMDS as small as ∼104 M ⊙ at z ∼ 12 with ∼106 s exposure. Differentiating SMDSs from early galaxies containing zero metallicity stars at similar redshifts requires spectral, photometric, and morphological comparisons. With only RST, the differentiation of SMDS, particularly those formed via adiabatic contraction with M ≳ 105 M ⊙ and lensed by μ ≳ 100, is possible due to their distinct photometric signatures from the first galaxies. Those formed via dark matter capture can be differentiated only by image morphology: i.e., point object (SMDSs) versus extended object (sufficiently magnified galaxies). By additionally employing James Webb Space Telescope (JWST) spectroscopy, we can identify the He ii λ1640 absorption line, a smoking gun for SMDS detection. Although RST does not cover the required wavelength band (for z emi ≳ 10), JWST does; hence, the two can be used in tandem to identify SMDS. The detection of SMDS would confirm a new type of star powered by dark matter and may shed light on the origins of the supermassive black holes powering bright quasars observed at z ≳ 6.

Chemical constituents of the roots of Kniphofia schimperi and evaluation of their antimicrobial activity

Kniphofia schimperi is one of the endemic plants of Ethiopia and is widely used for the treatment of microbial infections. However, the biological and phytochemical information pertaining to this plant has not been reported so far. Anticipated by these claims, the chromatographic isolation of the CHCl3/CH3OH (1:1 v/v) extract of the roots of K. schimperi afforded five compounds, viz., knipholone (1), asphodeline (2), β-sitosterol (3), 9-pentacosenoic acid (4), and nonacosanoic acid (5). The structures of the isolated compounds were identified based on their NMR (1D and 2D) spectral data analysis and comparison with reported literature data. The crude extract and isolated compounds were evaluated for their in vitro antimicrobial activity against four bacterial strains (Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Bacillus cereus) and a fungal strain (Candida albicans) using the agar disk diffusion method. The test samples showed moderate antimicrobial activity, with the highest activity observed for compound 3 (with a zone of growth inhibition of 15.5 ± 0.71 mm) against S. typhimurium.

Phenolic Acids, Steroids, and Triterpenoids Isolated from Platycodon grandiflorus (Jacq.) A. DC.

Platycodon grandiflorus (Jacq.) A. DC. is a precious medicinal plant, which is one of 54 medicinal species selected by the Vietnamese government for development in specialized areas of medicinal herbs. Currently, P. grandiflorus has been planted in some regions in Vietnam. Although P. grandiflorus has been commonly used in traditional Vietnamese medicine, the reports on the chemical composition and biological activity of this plant are limited in our country. As a part of our research on the hypolipidemic effect of P. grandiflorus, six compounds including ferulic acid (1), caffeic acid (2), p-hydroxy benzoic acid (3), spinasterol (4), sitostenone (5), and betulin (6) were isolated from the ethyl acetate and n-hexane extracts of the roots of P. grandiflorus. The structures of these compounds were determined based on NMR and MS spectral data and comparison with those reported in the literature. Compound 5 has been found in P. grandiflorus for the first time.

Formation of ketoprofen methyl ester artifact in GC–MS analysis of basic drugs in horse urine using alkaline liquid-liquid extraction

This study investigates the unexpected formation of ketoprofen methyl ester (KME) during the routine alkaline liquid–liquid extraction (LLE) process for analyzing basic drugs in horse urine samples using GC–MS analysis. An unidentified peak in the GC–MS chromatogram was observed in certain horse urine samples, identified as KME through mass spectral comparison with in situ synthesized KME. Since the KME is not a metabolite of ketoprofen present in urine, it is proposed that its formation occurs during the LLE process due to the reaction between ketoprofen contained in the urine and methanol used as the solvent of the spiked internal standard. Surprisingly, no artifact was detected when negative quality control horse urine samples (absence of ketoprofen) even when spiked with standard ketoprofen and methanol. Further investigation indicated that the presence of lipase enzymes from bacteria in specific urine samples is the key factor in the formation of the KME artifact. This hypothesis was confirmed when negative quality control horse urines were spiked with ketoprofen, methanol, and a lipase enzyme and the KME artifact was detected. Additionally, the formation of a methyl ester artifact was also detected for flunixin, a carboxylic acid NSAID drug, when negative quality control horse urines were spiked with the drug, methanol, and lipase enzyme. These findings will be valuable for scientists analyzing drugs in urine.

Seven new triterpenoids from the roots of Adenophora tetraphylla (Thub.) Fisch

Seven new triterpenoids, named Adeterpenoids A-G (1–7) and eight known compounds (8–15), were isolated from 70% ethanol extract of the roots of Adenophora tetraphylla (Thub.) Fisch. The compounds from it were separated by column chromatography techniques such as silica gel, ODS, and preparative liquid chromatography. Their structures were clarified based on extensive spectral analysis (1D, 2D-NMR, HR-ESI-MS, IR, UV, and CD) and comparison with the literature. At the same time, all compounds were evaluated for their cytotoxic activity against the LN229 (human glioma cell line). The results showed that compounds 2, 5, 6, 13, and 14 had a significant inhibitory effect on LN229 cells.

Spectral characteristics of particle preferential concentration in turbulence computed by Eulerian and Lagrangian methods

This study conducts a comprehensive analysis of the Fourier spectra characteristics of particle preferential concentration in turbulent flows obtained by Eulerian and Lagrangian modelling approaches for different Stokes numbers. Particle preferential concentration is characterized by clusters and voids in the spatial particle distributions formed in turbulent flows and can significantly influence processes such as droplet coalescence, evaporation, and gas-particle reactions. The research primarily focuses on comparing the performance of two Eulerian models—one with and one without second-order velocity moments—and one Lagrangian model, which are used to predict particle dispersion. Key findings include the impact of artificial diffusion in Eulerian methods, the superiority of methods incorporating second-order velocity moments contributions at higher Stokes numbers, and the sensitivity of the Lagrangian method to Poisson statistics. Notably, the study reveals minimal variation in mean velocity spectra across different Stokes numbers, as opposed to the marked variations in particle concentration, momentum, and energy spectra. Grid resolution emerges as a crucial factor in enhancing spectral energy predictions in Eulerian methods. The research underscores the nuanced distinctions between Eulerian and Lagrangian methods in modelling preferential concentration, providing a detailed spectral comparison of particle concentration, velocity, momentum, and energy, highlighting the importance of method selection based on specific modelling needs.