Analysis Method Research Articles

Relationship between human serum metabolites and angina pectoris: a Mendelian randomization study.

We aimed to explore the causal relationship between human serum metabolites and angina pectoris. This study used two-sample Mendelian randomization (MR) analysis to assess the association between 486 serum metabolites and angina pectoris. The analytical methods employed to reduce study bias included inverse variance weighted, MR-Egger, and weighted median method. A comprehensive sensitivity analysis was performed using the leave-one-out method, while instrumental variable pleiotropy was tested with MR-Pleiotropy RESidual Sum and Outlier. Metabolic pathways of angina-associated metabolites were analysed on the MetaboAnalyst metabolomics analysis tool platform. In this study, 42 serum metabolites were found to be strongly associated with angina pectoris. They mainly belonged to seven groups: amino acids, carbohydrates, cofactors and vitamins, lipids, nucleotides, unknown metabolites, and exogenous substances. Pipecolate posed the highest risk for the development of angina pectoris among the 42 serum metabolites. The main metabolic pathways associated with angina pectoris were glycine, serine, threonine metabolism, primary bile acid biosynthesis, and caffeine metabolism. We identified 25 high-risk and 17 protective human serum metabolites associated with angina pectoris. Their associated major metabolic pathways were also determined. The serum metabolite pipecolate was significantly and positively correlated with the risk of angina pectoris. This finding may serve as a valuable reference for testing serum markers associated with angina pectoris.

Green synthesis of gold nanoparticles using Pelargonium Graveolens leaf extract: characterization and anti-microbial properties (An in-vitro study)

Background In recent years, there has been a notable increase in the level of attention devoted to exploring capabilities of nanoparticles, specifically gold nanoparticles AuNPs, within context of modern times. AuNPs possess distinct biophysical properties, as a novel avenue as an antibacterial agent targeting Streptococcus Mutans and Candida Albicans. The aim of this study to create a nano-platform that has the potential to be environmentally sustainable, in addition to exhibiting exceptional antimicrobial properties against Streptococcus Mutans as well as Candida Albicans. Methods this study involved utilization of Pelargonium Graveolens leaves extract as a cost effective and environmentally sustainable approach for the green synthesis of AuNPs. Subsequently, physicochemical characteristics were assessed employing a variety of analytical methods, including as transmission electron microscopy, X-ray diffraction, Field Emission Scanning Electron Microscope, Zeta potential, Ultraviolet visible absorption spectroscopy, and Energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The antimicrobial efficacy against Streptococcus Mutans and Candida Albicans was evaluated. Nanoparticles of various shapes, including hexagonal, spherical, semi-spherical, and triangular, were synthesized. These nanoparticles exhibited a mean particle size of 294nm and demonstrated low degree of aggregation. These nanoparticles exhibited long-term stability and were capable of facilely combining with diverse bioactive compounds. Results The study demonstrated that AuNPs which is synthesized by green methods display potent antimicrobial properties. Conclusion Utilization of Pelargonium Graveolens AuNPs may exhibit a promising potential as an antibacterial agent against Streptococcus Mutans and Candida Albicans. Nanoparticles (NPs) have the potential to serve as a novel approach for addressing pathogen infections as well as for biomedical, dental and pharmaceutical purposes in the future.

First in situ Lu–Hf garnet date for a lithium–caesium–tantalum (LCT) pegmatite from the Kietyönmäki Li deposit, Somero–Tammela pegmatite region, SW Finland

Abstract. The in situ Lu–Hf geochronology of garnet, apatite, fluorite, and carbonate minerals is a fast-developing novel analytical method. It provides an alternative technique for age dating of accessory minerals in lithium–caesium–tantalum (LCT) rare-element (RE) pegmatites where zircon is often metamict due to alteration or radiation damage. Currently most dates from Finnish LCT pegmatites are based on columbite-group minerals (CGMs), but their occurrence is restricted to mineralised zones within the pegmatites. Accessory minerals such as garnet and apatite are widespread in both mineralised and unmineralised LCT pegmatites. Lu–Hf dating of garnet and apatite provides an exceptional opportunity to better understand the geological history of these highly sought-after sources for battery and rare elements (Li, Nb, Ta, Be) that are critical for the green transition and its technology. In this paper we present the first successful in situ Lu–Hf garnet date of 1801 ± 53 Ma for an LCT pegmatite from the Kietyönmäki deposit in the Somero–Tammela pegmatite region, SW Finland. This age is consistent with previous zircon dates obtained for the region, ranging from 1815 to 1740 Ma with a weighted mean 207Pb / 206Pb age of 1786 ± 7 Ma.

Simultaneously Estimation of Multicomponent Containing Formulation by using UV-Spectroscopy [Aspirin-Atorvastatin

The market is currently offering a wide range of combination dose forms, and the quantity is growing daily. Due to their improved potency, various actions, speedier relief, fewer side effects, and higher patient acceptability, these multicomponent formulations are becoming more and more popular. It is therefore intended that these formulations satisfy all requirements for their efficacy, safety, and quality. This is only feasible if many analytical methods are available to determine them. When doing a simultaneous multicomponent analysis, various UV spectrophotometric techniques are applied.These techniques rely on logging and processing absorption spectra computationally. The various techniques covered in this review include the use of simultaneous equations, derivative spectrophotometry, mean centring of the ratio spectra, absorption factor method, double divisor ratio spectra derivative method, successive ratio derivative spectra, Q-absorbance ratio method, isosbestic point method, absorpitivity factor method, dual wavelength method, mean centring of the ratio spectra, and multivariate methods. A synopsis of the theories and a few uses for these techniques are given.

Green Biosynthesis of TiO2 Nanoparticles Using Aqueous Extract of Brassica juncea (L.) Czern Seed: Characterization, Antimicrobial, Antioxidant and Anticancer Activities

AbstractPrimary objective of this research was to examine the biogenic production of TiO2 NPs using Brassica juncea (L.) Czern seed and investigate the prospective uses of thus synthesized nanoparticles in the area of biomedicine. The synthesized TiO2 NPs were subjected to characterization using several analytical methods namely TEM, UV‐vis, XRD, FE‐SEM, FTIR and EDAX. The average particle size (TEM) is found to be 38 nm, exhibiting irregular shapes. The FT‐IR spectra indicated that the extract contains functional groups, such as polyphenolic, hydroxyl and carboxylic groups, which are likely responsible for formation of nanoparticles. The cytotoxicity studies of the synthesized TiO2 NPs against breast cancer cells (MCF‐7) and lung cells (A549) are shown to be dosage dependent. The inhibitory doses (IC50) were determined to be 43.98 μg/mL and 74.50 μg/mL on MCF‐7 and A549 cells, respectively. Green synthesized TiO2 NPs were assessed for antioxidant activity inhibition rate (DPPH 89.42 %). TiO2 NPs exhibited a maximal zone of inhibition of Staphylococcus aureus 23±0.20 mm against and 20±0.30 against Klebsiella pneumoniae at a concentration of 100 μg/mL, indicating strong antibacterial activity. The findings suggest Brassica juncea (L.) Czern seed encapsulated TiO2 NPs possesses excellent biological applications which can be explored for its application in pharmaceutical field.

Psychometric Properties of a Psychological Measure of Indigenous Personality (Suryomentaram's Perspective): Initial Study

Background Character development is central in personality and developmental psychology, with strong character as a protective factor against psychological disorders. Given the importance of character assessment, this study explores the development and initial psychometric evaluation of an indigenous personality measure, the Suryomentaram Personality Scale (SPS), grounded in empirical research on individuals trained in Suryomentaram philosophies. Objective The study aimed to (1) develop the SPS and (2) evaluate its psychometric properties, including content validity, factor structure, and internal consistency reliability. Methods Three analytical methods were employed: content validity assessment by six subject matter experts (SMEs), exploratory factor analysis (EFA), and reliability analysis. A convenience sample of 282 students participated in EFA and reliability analyses. Participants were recruited through social media announcements and provided informed consent before completing the SPS. Results Content validity analysis revealed eight items falling below the acceptable Aiken's V threshold (< 0.8) out of 23 initially developed items. EFA of the remaining 15 items identified four relatively independent factors: perseverance, optimism, lack of worry and regret, and empathy. Internal consistency reliability estimates for each factor ranged from 0.482 to 0.716. Conclusion This initial study provides evidence for the adequate psychometric properties of the SPS based on content validity, EFA, and reliability analysis. Further research is needed to confirm these findings and explore the scale's convergent and discriminant validity.

Fabrication and Characterization of Photocatalyst Pb3CdO7 for Degradation of Azure-A

Present work comprises of fabrication of the novel Pb3CdO7 ternary oxide composite from the corresponding precursors using a co-precipitation approach and calcined. The as-prepared material is then characterized by FTIR, FE-SEM, XPS, EDX, XRD, HR-TEM etc. analytical methods. Based on UV-Vis-NIR spectroscopy, the composite's direct energy band gap is determined to be 5.23 eV, which makes it an effective photocatalyst. The prepared photocatalyst is found to degrade Azure-A dye with an efficiency of up to 94.87%. Scavenger study suggests the participation of active free radicals O2•- (superoxide anion radical) as the responsible species in breakdown of the dye molecules. The operating parameters are controlled to maximize the photodegradation and a kinetic study is carried out. Used photocatalyst is recycled and is found to work at the same pace for up to five cycles.

Devoting turbidity measurements via absorptiometry: glutathione determination

The study included estimation of glutathione (GSH) as an important biomarker using turbidimetric method based on reaction of GSH with Ce(IV) in acidic medium to form turbid solution. More than twenty metal ions were used to test their interaction with GSH in acidic medium, it was obtained that only Ce(IV) forms turbid product. Instead of using turbidimeter to conduct measurements, a single beam spectrophotometer was used for this purpose. The measurements were studied at three wavelengths via 500, 700 and 900nm, but a near infrared wavelength, i.e. 900nm, shows the best results. In addition, the effect of temperature, time, type of acid, sequence addition as an optimum conditions required for the product to form were studied. Then the effect of the interferences was studied at two concentrations. A calibration curve in µg.mL-1 was constructed and its trending lies on points of concentrations ranged from 20 to 180µg.mL-1 with a correlation coefficient of 0.9994, and detection limit of 0.0005 µg.mL-1 and slope is (0.0014). The analytical method was applied on samples of human blood serum. The obtained results were compared with the results of the referenced (kit) method. The results obtained by the method followed, some of them were close and the others were far.

Customized Hydrogel Films for MicroRNA Super-Resolution Imaging in Liquid Biopsies.

Tissue biopsy for early diagnosis and monitoring comes with several challenges, such as its invasiveness, and issues related to tissue heterogeneity in sampling. To address these issues, researchers have proposed a noninvasive approach called liquid biopsy, which uses blood samples to detect specific noncoding RNA (microRNA, miRNA). However, the current process of isolating and amplifying miRNA can be time-consuming and yield nonspecific results. In this study, a new super-resolution imaging tool is introduced that utilizes a thin, hydrogel-based liquid view (LV) film. This film can undergo a ninefold expansion and allows the analysis of cells obtained from liquid biopsy. The potential of the LV film is validated as a tool for early diagnosis and prognosis by testing biofluids derived from a variety of diseases. This method is confirmed to accurately analyze a greater number of miRNAs with higher sensitivity in a shorter time compared to other analytical methods. These findings suggest that the LV film provides high specificity, and multiplexing in detecting small amounts of miRNAs within cells, making it suitable for 3D implementation. It is proposed that liquid biopsy with LV films can be a solution to limitations related to the invasiveness, cost, and time-consuming nature of molecular analysis.

Plastic zone characteristics and rapid stability evaluation indexes of circular tunnels subjected to non-hydrostatic stress: A novel complex variable solution incorporating 3D rock mass strength

The morphological characteristics and distribution range of the plastic zone around tunnels, influenced by the true three-dimensional high geostress environment in deep engineering, constitute fundamental reference data for both tunnel design and the control of surrounding rock stability. Based on the GZZ three-dimensional rock mass strength criteria and the complex variable method, a novel semi-analytical method for solving the plastic zone of a circular tunnel subjected to non-hydrostatic stress is presented. The conformal mapping is employed to intricately transform the complex boundaries of plastic zones characterized by diverse shapes onto the unit circle boundary within the image plane. This framework proves invaluable for the precise analytical process of the complex plastic zone morphology and the plastic influence range within the surrounding rock under complex stress conditions. In contrast to traditional analytical methods, the efficacy and versatility of our proposed approach are substantiated. Notably, it demonstrates unique advantages, particularly in the context of non-hydrostatic stress fields and varied rock mass parameters, with respect to predicting both surrounding rock stability and plastic zone morphology. Through the analysis of numerous cases, the study reveals the systematic patterns of influence that in-situ stress and surrounding rock characteristic parameters have on the shape and maximum depth of the plastic zone. The results indicate that (1) there are notable disparities in the morphology and extent of the plastic zone between the GZZ and GHB criteria; (2) the transition of the plastic zone in surrounding rock from U-shaped to V-shaped is significantly influenced by the geostress-to-strength ratio Kσ; (3) there is a notable linear correlation observed between the maximum plastic zone thickness rmax and both Kσ and the stress concentration factor KSCF, importantly, this correlation is independent of far-field stress and the brittleness characteristics of the surrounding rock. These findings provide a novel discriminative method for the rapid analysis of surrounding rock stability in deep circular tunnels.

New Lie Symmetries and Exact Solutions of a Mathematical Model Describing Solute Transport in Poroelastic Materials

A one-dimensional model for fluid and solute transport in poroelastic materials (PEMs) is studied. Although the model was recently derived and some exact solutions, in particular steady-state solutions and their applications, were studied, special cases occurring when some parameters vanish were not analysed earlier. Since the governing equations are nonintegrable in nonstationary cases, the Lie symmetry method and modern tools for solving ODE systems are applied in order to construct time-dependent exact solutions. Depending on parameters arising in the governing equations, several special cases with new Lie symmetries are identified. Some of them have a highly nontrivial structure that cannot be predicted from a physical point of view or using Lie symmetries of other real-world models. Applying the symmetries obtained, multiparameter families of exact solutions are constructed, including those in terms of elementary and special functions (hypergeometric, Whittaker, Bessel and modified Bessel functions). A possible application of the solutions obtained is demonstrated, and it is shown that some exact solutions can describe (at least qualitatively) the solute transport in PEM. The obtained exact solutions can also be used as test problems for estimating the accuracy of approximate analytical and numerical methods for solving relevant boundary value problems.

Screening Conductive MXenes for Lithium Polysulfide Adsorption

AbstractMXenes are promising passive components that enable lithium‐sulfur batteries (LSBs) by effectively trapping lithium polysulfides (LiPSs) and facilitating surface‐mediated redox reactions. Despite numerous studies highlighting the potential of MXenes in LSBs, there are no systematic studies of MXenes’ composition influence on polysulfide adsorption, which is foundational to their applications in LSB. Here, a comprehensive investigation of LiPS adsorption on seven MXenes with varying chemistries (Ti2CTx, Ti3C2Tx, Ti3CNTx, Mo2TiC2Tx, V2CTx, Nb2CTx, and Nb4C3Tx), utilizing optical and analytical spectroscopic methods is performed. This work reports on the influence of polysulfide concentration, interaction time, and MXenes’ chemistry (transition metal layer, carbide and carbonitride inner layer, surface terminations and structure) on the amount of adsorbed LiPSs and the adsorption mechanism. These findings reveal the formation of insoluble thiosulfate and polythionate complex species on the surfaces of all tested MXenes. Furthermore, the selective adsorption of lithium and sulfur, and the extent of conversion of the adsorbed species on MXenes varied based on their chemistry. For instance, Ti2CTx exhibits a strong tendency to adsorb lithium ions, while Mo2TiC2Tx is effective in trapping sulfur by forming long‐chain polythionates. The latter demonstrates a significant conversion of intermediate polysulfides into low‐order species. This study offers valuable guidance for the informed selection of MXenes in various functional components benefiting the future development of high‐performance LSBs.

Investigation of Retention Mechanism of B2 and B3 in Home-Made ZIC-HILIC Columns and Its Application for The Simultaneous Estimation in Multivitamin Tablets

In the present study, the retention behavior of two vitamins (B2 and B3) was investigated using a zwitterionic hydrophilic interaction liquid chromatography technique (ZIC-HILIC) on two home-made columns, and two analytical methods for these vitamins were established as a result. Several chromatographic parameters were carefully investigated and optimized. The best separation was achieved on two new home-made columns (ZIC-1 and ZIC-3) employing acetonitrile/sodium acetate buffer as the mobile phase (40 mM, pH 4.75). The target vitamins were detected at 254 nm. In the ZIC-1 and ZIC-3 columns, the linear ranges of the target vitamins (B2 and B3) were 0.06-11.0 and 0.08-7.0 µg/mL, respectively. For both target vitamins, the detection and quantitation limits of the suggested methods were 0.011-0.055 and 0.033-0.166 µg/mL, respectively. They also showed high precision (RSD ≤ 0.93), linearity (r2 ≥ 0.9988), and recovery (between 99.0 and 101.71%). The suggested procedures have been validated and tested on multivitamin tablets, proving that they are suitable for analyzing food supplements for these tablets, and acceptable results were obtained for the study.

Advanced Analytical Techniques for Characterizing Petroleum-Derived Contaminants in the Environment

The characterization of petroleum-derived contaminants in the environment is crucial for understanding their impact on ecosystems and human health. Traditional analytical techniques such as Gas Chromatography (GC), Mass Spectrometry (MS), and High-Performance Liquid Chromatography (HPLC) have been instrumental in identifying and quantifying these contaminants. However, the complexity and diversity of petroleum-derived compounds necessitate the development and application of advanced analytical techniques for more comprehensive analysis. This paper reviews the most cutting-edge methods currently employed in environmental analysis, including Comprehensive Two-Dimensional Gas Chromatography (GC×GC), Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS), Nuclear Magnetic Resonance (NMR) Spectroscopy, and Synchrotron Radiation-Based Techniques such as X-ray Absorption Spectroscopy (XAS) and X-ray Fluorescence (XRF), as well as Laser-Induced Breakdown Spectroscopy (LIBS). Each technique's principles, capabilities, and applications are discussed, highlighting their roles in detecting and characterizing hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), heavy metals, and volatile organic compounds (VOCs). Case studies demonstrate the practical applications of these advanced techniques in real-world scenarios, such as oil spill analysis and the identification of complex contaminant mixtures. The paper also addresses the advantages and limitations of these advanced techniques, considering factors like sensitivity, selectivity, complexity, and cost. Finally, future directions and emerging technologies, including nanotechnology, biosensors, and machine learning, are explored for their potential to enhance environmental monitoring and remediation efforts. This comprehensive review underscores the importance of continued innovation in analytical methods to effectively address the challenges posed by petroleum-derived contaminants in the environment.

The Role of Technology in Enhancing Adaptive Behavior Skills for Students with Intellectual Disabilities

The current study documents key contributions in teaching students with intellectual disabilities using an integrative STEAM approach. This study aimed to understand the role of technology and arts-based methodologies in improving adaptive behavior skills for students with intellectual disabilities. The researcher used descriptive analytical methods to review, analyze, compare, and interpret related theories and literature. The study highlights how technology and arts-based approaches enhance adaptive skills and support development in self-care, mobility, educational skills, independence, performance, and community integration for these students. The promising finding is that an integrative STEAM approach, incorporating technology and arts-based learning, improves adaptive behavior skills for students with intellectual disabilities. Based on the results, the researcher recommends that the Ministry of Education provide guidance, counseling, seminars, and workshops for teachers on using assistive technology and arts-based methodologies due to their importance in rehabilitating and educating individuals with intellectual disabilities.

Examining functional group-dependent effects on the ionization of lignin monomers using supercritical fluid chromatography/electrospray ionization mass spectrometry.

The chemical and biological conversion of biomass-derived lignin is a promising pathway for producing valuable low molecular weight aromatic chemicals, such as vanillin or guaiacol, known as lignin monomers (LMs). Various methods employing chromatography and electrospray ionization-mass spectrometry (ESI-MS) have been developed for LM analysis, but the impact of LM chemical properties on analytical performance remains unclear. This study systematically optimized ESI efficiency for 24 selected LMs, categorized by functionality. Fractional factorial designs were employed for each LM to assess ESI parameter effects on ionization efficiency using ultra-high-performance supercritical fluid chromatography/ESI-MS (UHPSFC/ESI-MS). Molecular descriptors were also investigated to explain variations in ESI parameter responses and chromatographic retention among the LMs. Structural differences among LMs led to complex optimal ESI settings. Notably, LMs with two methoxy groups benefited from higher gas and sheath gas temperatures, likely due to their lower log P and higher desolvation energy requirements. Similarly, vinyl acids and ketones showed advantages at elevated gas temperatures. The retention in UHPSFC using a diol stationary phase was correlated with the number of hydrogen bond donors. In summary, this study elucidates structural features influencing chromatographic retention and ESI efficiency in LMs. The findings can aid in developing analytical methods for specific technical lignins. However, the absence of an adequate number of LM standards limits the prediction of LM structures solely based on ESI performance data.

Parent attitudes towards data sharing in developmental science

Background Data sharing in developmental science is increasingly encouraged, supported by funder and publisher mandates for open data access. Data sharing can accelerate discovery, link researchers with high quality analytic expertise to researchers with large datasets and democratise the research landscape to enable researchers with limited funding to access large sample sizes. However, there are also significant privacy and security concerns, in addition to conceptual and ethical considerations. These are particularly acute for developmental science, where child participants cannot consent themselves. As we move forward into a new era of data openness, it is essential that we adequately represent the views of stakeholder communities in designing data sharing efforts. Methods We conducted a comprehensive survey of the opinions of 195 parents on data sharing in developmental science. Survey themes included how widely parents are willing to share their child’s data, which type of organisations they would share the data with and the type of consent they would be comfortable providing. Results Results showed that parents were generally supportive of curated, but not open, data sharing. In addition to individual privacy and security concerns, more altruistic considerations around the purpose of research were important. Parents overwhelmingly supported nuanced consenting models in which preferences for particular types of data sharing could be changed over time. This model is different to that implemented in the vast majority of developmental science research and is contrary to many funder or publisher mandates. Conclusions The field should look to create shared repositories that implement features such as dynamic consent and mechanisms for curated sharing that allow consideration of the scientific questions addressed. Better communication and outreach are required to build trust in data sharing, and advanced analytic methods will be required to understand the impact of selective sharing on reproducibility and representativeness of research datasets.

Resolution of multiple semi-infinite delaminations using lock-in infrared thermography

Delaminations are flat subsurface defects parallel to the sample surface. Recently we have demonstrated that lock-in infrared thermography, with optical excitation, allows sizing the geometrical parameters (length, depth and thickness) of a semi-infinite delamination. Here, we analyse the ability of this technique to resolve several parallel and semi-infinite delaminations. First, we develop an analytical method (based on the thermal quadrupoles) together with a numerical formulation to calculate the surface temperature of a sample containing several semi-infinite parallel delaminations. We verify that both methods provide the same temperature values, indicating their consistency. Then, we study the ability of lock-in infrared thermography to resolve two close delaminations. In particular we focus on two main configurations: two non-overshadowed delaminations and two superimposed delaminations. Next, after analysing the inverse problem in terms of residual function minimization, we develop a dedicated parametric estimation procedure able to retrieve the geometry of the studied defects. Finally, we test this procedure with synthetic temperature amplitude and phase data to retrieve the geometrical parameters of both delaminations.

Analytical method for time-varying meshing stiffness and dynamic responses of modified spur gears considering pitch deviation and geometric eccentricity

Pitch deviation and geometric eccentricity are almost inevitable in gear transmission systems. Tooth profile modification (TPM) is a common method used to improve gear contact properties. However, the coupling interaction between the tooth profile deviation introduced by TPM and manufacturing errors is complex. There is a lack of an analytical model that can clarify the dynamic behaviors of the modified gear pair affected by multiple manufacturing errors, specifically pitch deviation and geometric eccentricity. To fill this gap, a comprehensive analytical gear mesh model is proposed considering TPM, pitch deviation, and geometric eccentricity. The calculation formulas for the time-varying meshing stiffness (TVMS) and load sharing factor (LSF) are derived considering the iterative change of gear pair meshing parameters with phase under the influence of multiple manufacturing errors. Then, the translation-torsion coupling dynamic model of the spur gear pair based on the lumped mass method is established to investigate the dynamic transmission error (DTE) and vibration characteristics. Results show that TPM is an effective method for improving the comprehensive stiffness of a gear pair within the meshing range containing pitch deviation, but it reduces the meshing phase that includes only geometric eccentricity. Compared with the unmodified gear pair, the suppression effect of changing the modification length on the maximum DTE and vibration acceleration is more significant than that of the modification amount. TPM increases the overall fluctuation threshold range of DTE for gear pairs with only geometric eccentricity. It is expected that the proposed method can provide a theoretical basis for exploring vibration suppression in gear pairs with geometric eccentricity and pitch deviation errors.

Economic concentration in the Russian leasing market

Aim. To determine the degree of concentration of the leasing market in Russia.Objectives. To calculate the leasing market concentration index; to assign the level of monopolization to each of the leasing market segments and justify the difference in the obtained levels; to formulate promising directions for further study of the leasing market concentration.Methods. The author used empirical and analytical methods of research. The author calculated the Herfindahl-Hirschman index to determine the level of concentration of the market as a whole and in terms of segments to verify the hypotheses put forward in the research about the presence of monopolization in the market of leasing services in Russia and different levels of concentration in the segments of the leasing market.Results. The market of leasing services in Russia is not highly concentrated, despite the presence of major players that occupy a significant market share: the top-3 account for about half of the market volume, the top-10 — 80%. In segments that do not require large amounts of financing, such as special equipment, buses and trolleybuses, and trucks, there is insignificant market concentration. Segments with larger deals, such as real estate, aviation transport, ships (sea and river), are highly concentrated.Conclusions. Contrary to the opinion of some market participants about strong concentration of the leasing market, there is no such concentration in the Russian market. High concentration exists only in the segments in which the average transaction check exceeds the capacity of a number of small lessors to provide financing.