Analysis Method Research Articles

Exogenous Versus Endogenous Nandrolone in Doping Investigations: A Systematic Literature Review

Nandrolone, or 19-nortestosterone, is an anabolic steroid derived from testosterone, known for its androgenic and anabolic effects. Often used illicitly by athletes to boost performance, its use is banned by the World Anti-Doping Agency (WADA) in and out of competition. Nandrolone’s main metabolites, 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE), are typically detected in urine. This systematic review, registered with PROSPERO and following PRISMA guidelines, examines nandrolone’s metabolism, factors affecting its natural production, and the analytical methods used in doping tests. Searches on PubMed, Scopus, and Web of Science yielded 517 studies, of which 57 were selected for analysis after excluding duplicates and unrelated articles. Descriptive statistics were applied to assess data on metabolic pathways, endogenous production influences, and detection techniques. Based on this review, it clearly emerges that the only technique that can distinguish endogenous production from an exogenous intake is gas chromatography/combustion/isotope ratio mass spectrometry (GC-C-IRMS). In addition, factors influencing endogenous production are considered and explored. Overall, this review provides useful information regarding nandrolone and its main metabolites.

ЧИННИКИ, ЯКІ ОБУМОВЛЮЮТЬ ВИНИКНЕННЯ НЕПРАЦЮЮЧИХ (ПРОБЛЕМНИХ) АКТИВІВ У БАНКІВСЬКІЙ СФЕРІ В СУЧАСНИХ УМОВАХ

Today, Ukraine is in an extremely difficult economic, social and political situation, which in turn determines the need to ensure the effective functioning of all spheres of the state's life, especially its financial sector. An important element of the latter is the banking system, which in the conditions of a full-scale war faced a large number of risks, among which a special place is given to non-working (problem) assets. At the same time, it should be noted that the emergence of non-performing (problem) assets in the banking sector is determined by a number of factors of a diverse nature. Objective. The article, based on the analysis of the scientific views of scientists, the norms of the current legislation and the practice of its implementation, highlights the factors that cause the emergence of non-performing (problem) assets in the banking sector in modern conditions. Methods. In the process of preparing a scientific study, a number of both general and special methods of scientific knowledge were used. Thus, the analytical method and the method of documentary analysis were used in order to identify the problems causing the emergence of (problem) assets in the banking sector. The method of systematization and classification was used in order to form the author's vision of the factors that cause the emergence of non-performing (problem) assets in the banking sector. Results. It is argued that the factors causing the emergence of non-performing (problem) assets in the banking sector should be divided into two large groups: 1) external, in particular: a) regulatory and legal; b) political; c) financial and economic; d) safe; e) demographic; 2) internal factors, which include: a) organizational and managerial factors; b) personnel; c) informational and analytical. Scientific novelty. The scientific novelty of the research lies in the fact that the theoretical approach to the definition of the key factors causing the emergence of non-performing (problem) assets in the banking sector in modern conditions was further elaborated in it. Practical significance. To solve the theoretical and practical problems causing the emergence of non-performing (problem) assets in the banking sector in modern conditions. Keywords: factors, banks, banking activity, non-performing, problem assets, financial sphere, banking sphere.

Ecological conditions of vineyards and the polymorphism of Saccharomyces cerevisiae strains as a prerequisite of terroir identification

Aim. The aim of the study was to assess whether the ecological conditions for vineyards and the phylogenetic analysis of Saccharomyces cerevisiae wine yeast strains isolated from several locations in the Odesa and Mykolayiv regions could be used for terroir identification. Methods. The study employed microbiological, analytical, expedition, cartographic, and comparative assessment methods. Phylogenetic analysis was conducted using the MEGA software program, and VIN-CAD-UKR software was used for the vineyard cadastre and the ampelecological characteristics data management. Results. The study highlighted differences in the ecological conditions of vineyards in the Odesa and Mykolayiv regions and within the Tairovo and Izmail territorial communities in the Odesa region, focusing on soil and microclimatic characteristics. Saccharomyces cerevisiae strains isolated in 2012 and 2013, years with varying weather conditions in temperature and precipitation, were primarily clustered by the year of isolation. Two notable exceptions included a strain isolated from the Isabela variety belonging to a hybrid group (direct producer, contrary to other varieties, which mainly represent Vitis vinifera or its hybrids with Vitis riparia, Vitis amurensis, Vitis berlandieri) and a strain isolated from the Odesa Black variety inoculated at the beginning of fermentation with a commercial strain of wine yeast. The 2013 isolates, collected under conditions of higher precipitation and lower temperature in the first half of the growing season, showed a more differentiated clustering pattern, with two strains isolated from the Sukholymansky White variety forming a distinct cluster, while the rest grouped together, irrespective of the region, formed of isolation. Conclusions. Phylogenetic analysis of 64 strains of Saccharomyces cerevisiae isolated from 36 technical grape varieties based on the ITS1_5.8S_ITS2 nucleotide sequence demonstrated that the year of isolation (reflecting agroclimatic factors) was the primary influence on sample clustering. These factors, as components of the ecological conditions of terroir, form the foundation for terroir identification.

Investigating Yūsuf al-Qaraḍāwī’s Approach Towards Inter-Religious Encounters in the Light of His Teachings and Writings

This research seeks to investigate the approach of Yusuf al-Qaradawi toward inter-religious encounters in the light of his teachings and writings. As a prominent Islamic scholar and intellectual, Qaradawi’s teachings and writings have had a significant impact on the relationship between the Muslim community and others. The goal of this research is to provide an analysis of Qaradawi’s writings and teachings to extract his approach toward inter-religious encounters and relations, drawing on a range of primary and secondary sources. Through a critical examination of his views on this subject, the approach of Qaradawi toward inter-religious understanding and cooperation is emphasized. The descriptive, analytical, and critical methods are used in the entire work. A brief description of Yusuf al-Qaradawi’s life, intellectual development, and works on inter-religious encounters and understanding is provided. Analysis of how he approached inter-religious encounters and relations, and how his views and thoughts on this subject have been received by both Muslim and non-Muslim communities. The study expects to provide new insights into Yusuf al-Qaradawi’s approach to inter-religious engagements, which are relevant to the contemporary context of inter-religious relationships between Muslims and adherents of other religions.

Development of a simple test to quantify the consolidation properties of liquefied granular materials

AbstractLiquefaction can have devastating consequences by causing increased mobility of debris flows, tailings dam breaches, and settlement following seismic shaking. Observations on the consolidation behaviour of liquefied soils in 1-g or centrifuge shake table tests have permitted significant advancements in analytical and numerical methods to predict the rate and magnitude of consolidation settlement. However, advanced consolidation models introduce material parameters which are currently difficult to define quickly and at low cost. The objective of this paper is to demonstrate the development of a simple, low-cost test that can be used to quickly estimate the spatially and temporally varying coefficient of consolidation, which controls post-liquefaction settlements. Using the proposed simple setup, experiments were conducted on four uniformly graded sands of varying grain size and on one well-graded mixture. A range of analytical and numerical approaches from literature were assessed for their ability to back-analyse the observed pore pressure dissipation and settlement. Estimated values for the coefficient of consolidation were comparable between models and estimates of surface settlement matched well the experimental results. The simplicity of the proposed test combined with its low-cost and mobile nature, raise significant possibilities for quick estimations of the evolution of the coefficient of consolidation post-liquefaction.

The Development of a High-Throughput Homonuclear Decoupling HSQC NMR Platform for the Determination of 10 Sex Hormones in Animal-Source Food and Medicines

Owing to their endocrine disruption effect, the hormone levels in animal-source food and medicines need to be efficiently and accurately quantified by a reliable analytical method. In the current study, by using a homonuclear decoupling and heteronuclear single quantum correlation (HSQC) experiment, coupled with non-uniform sampling (NUS) that was used to shorten the experimental time, we developed a method to quantify 10 hormone residues in animal-source products. This method was validated following the guidelines of USP–NF 2022. The application of the homonuclear decoupling (HD) technique to conventional HSQC yielded 2D spectra that exhibited excellent signal separation and specificity. For all the tested hormones, good linearity with correlation coefficients of more than 0.99 was observed in the linear range of 0.2–6 mg/0.6 mL. Satisfactory precision and recoveries of spiked animal samples were also obtained. Finally, the method was applied in residue determination of 10 hormones in real animal-source samples at the ug/g level.

Exploring the impact of digital knowledge, integration and performance on sustainable accounting, reporting and assurance

Purpose The purpose of this study is to perform bibliometric analysis to systematically and comprehensively examine the current landscape of digital knowledge, integration and performance in the transformation of sustainability accounting, reporting and assurance. Design/methodology/approach This research uses a systematic literature review, following the Scientific Procedures and Rationales for Systematic Literature Review protocol and uses various bibliometric and performance analytical methods. These include annual scientific production analysis, journal analysis, keyword cooccurrence analysis, keyword clustering, knowledge gap analysis and future research direction identification to evaluate the existing literature thoroughly. Findings The analysis reveals significant insights into the transformative impact of digital technologies on sustainability practices. Annual scientific production and journal analyses highlight key contributors to the adoption of digital technologies in sustainability accounting, reporting and assurance. Keyword cooccurrence analyses have identified key themes in sustainability accounting, reporting and assurance, highlighting the transformative role of digital technologies such as artificial intelligence (AI), blockchain, Internet of Things (IoT) and big data. These technologies enhance corporate accountability, transparency and sustainability by automating processes and improving data accuracy. The integration of these technologies supports environmental, social and governance (ESG) reporting, circular economy initiatives and strategic decision-making, fostering economic, social and environmental sustainability. Cluster-by-coupling analyses delve into nine broader revealing that IoT improves ESG report accuracy, eXtensible Business Reporting Language structures ESG data and AI enhances life cycle assessments and reporting authenticity. In addition, digital transformation impacts environmental performance, big data optimizes resource use and edge computing improves eco-efficiency. Furthermore, this study identifies avenues for future research to advance the understanding and implementation of digital technology in sustainability accounting, reporting and assurance practices. Research limitations/implications Academically, this research enriches the understanding of how digital technologies shape sustainability practices and identifies gaps in digital knowledge and integration. Practically, it provides actionable insights for organizations to improve sustainability reporting and performance by effectively leveraging these technologies. Policy-wise, the findings advocate for frameworks supporting the effective implementation of these technologies, ensuring alignment with global sustainability goals. Originality/value This study offers a detailed analysis of the performance and intellectual framework of research on implementing digital technology in sustainability accounting, reporting and assurance. It highlights the evolving research landscape and emphasizes the need for further investigation into how emerging technologies can be leveraged to achieve sustainability goals.

New mid‐Cretaceous macrothelids showing a similar living mode to extant Macrothelidae (Araneae: Mygalomorphae)

AbstractFive new spider fossils of the family Macrothelidae (Araneae: Mygalomorphae) are described from mid‐Cretaceous Kachin amber, Myanmar. A new genus Acanthomacrothele gen. nov. is established for three new species: Acanthomacrothele pauciverrucae sp. nov., Acanthomacrothele geminata sp. nov., and Acanthomacrothele longicaudata sp. nov. Both male and female specimens of A. pauciverrucae sp. nov. are described, representing a rare case of a fossil spider with both sexes known. We also describe an unidentified juvenile of Macrothelidae to document different developmental stages of Cretaceous species. To test the phylogenetic position of the new fossils, we undertook phylogenetic analyses using both topology‐unconstrained and topology‐constrained methods. Our analyses supported the placement of Acanthomacrothele gen. nov. in Macrothelidae, although its phylogenetic relationship to other genera of Macrothelidae differed among different analytical methods. The fossils documented here have elongated, widely spaced posterior lateral spinnerets, compact rectangular group of eyes on a tubercle, and more spines on male tibia of anterior legs than female, similar to extant macrothelids, suggesting that they probably have similar retreat construction behavior, habitat preference, and mating position to their living relatives.

Leveraging infrared spectroscopy for automated structure elucidation.

The application of machine learning models in chemistry has made remarkable strides in recent years. While analytical chemistry has received considerable interest from machine learning practitioners, its adoption into everyday use remains limited. Among the available analytical methods, Infrared (IR) spectroscopy stands out in terms of affordability, simplicity, and accessibility. However, its use has been limited to the identification of a selected few functional groups, as most peaks lie beyond human interpretation. We present a transformer model that enables chemists to leverage the complete information contained within an IR spectrum to directly predict the molecular structure. To cover a large chemical space, we pretrain the model using 634,585 simulated IR spectra and fine-tune it on 3,453 experimental spectra. Our approach achieves a top-1 accuracy of 44.4% and top-10 accuracy of 69.8% on compounds containing 6 to 13 heavy atoms. When solely predicting scaffolds, the model accurately predicts the top-1 scaffold in 84.5% and among the top-10 in 93.0% of cases.

Nutrients and Antioxidant Composition of Local Condiment “Ogiri” Produced from Different Leguminous Seeds

‘Ogiri’ refers to a fermented oily paste that is used as soup condiments for its strong smell. Apart from the fact that it’s mostly used in soup preparation because of the strong pungent odour and organoleptic properties, it also impact nutrients to soup. This study investigated the nutrients and antioxidant composition of Ogiri produced from different leguminous seeds. Raw material such as melon (EGU) and sesame (SES) seeds were procured from Oja Oba (Oba Market) in Owo, Ondo State while pumpkin (PUM) and Castor (CAS) seed were purchased at Upper Iweka market, Onitsha Anambra State, Nigeria. The raw materials were processed into ‘Ogiri’ using traditional methods and were subjected to chemical analysis using standard analytical methods.” Data generated were subjected to One-way Analysis of Variance (ANOVA) and means were separated using Duncan Multiple Range Test at 5% level of significance. Findings shows that the moisture content was significantly (P<0.05) higher in PUM than any other sample. Sample SES was significantly (P<0.05) higher in Ash (10.22g /100g) content, and fibre (11.21g/100g) while EGU was significantly (P<0.05) higher in fat (30.17g/100g) and protein (29.30g/100g). CAS had the highest carbohydrate content (27.58g/100g).Minerals result shows that Na (14.835mg/g), Ca (22.570mg/100g) and Mg (3.351mg/100g) were significantly (P<0.05) higher in sample EGU. Sample SES was significantly higher in K (55.855mg/100g) and Zn (0.308mg/100g), while CAS was significantly lower (P<0.05) in Na (3.45mg/100g), Ca (13.15mg/100g) K, (21.655mg/100g), Zn (0.128mg/100g) and Mg (1.925mg/mg) but has the highest value in P (12,252mg/100g). PUM was significantly higher in Vitamin E (8.270mg/100g), while CAS was significantly higher in vitamin A (7.576UI/g). Sample PUM had the highest Polyphenol and Terpenoid content (106.82mg/g and 1.37mg/g respectively) while sample SES had the highest steroid content (0.92mg/g). In conclusion, this study revealed that the nutrients and antioxidant properties of the “Ogiri” samples vary proportionately. The results can guide farmers, processors, and consumers in making informed decisions regarding seed selection and Ogiri preparation.

Characterization of poly(A) and poly(T) tail lengths in plasmid DNA by liquid chromatography high-resolution mass spectrometry.

Rapid advances in messenger RNA (mRNA) technology necessitate effective analytical methods. This study describes the development of a novel in vitro method using ion-pair reversed-phase liquid chromatography coupled to high-resolution mass spectrometry (IP-RP-LC-HRMS) for assessing the poly(A) and complementary poly(T) tail lengths directly into the DNA template used to manufacture mRNA. Briefly, after the validation of poly(A) tail length in the plasmid by Sanger sequencing, double-stranded DNA fragments containing these tails in the plasmid of interest were amplified by thepolymerase chain reaction (PCR), purified on silica column, and digested with restriction enzymes ClaI and HindIII. Gel or capillary electrophoresis confirmed sample quality and enzymatic digestion efficiency. Subsequently, poly(A) and complementary poly(T) tails were extracted and analyzed by LC-MS to determine their length and heterogeneity at a single-nucleotide resolution. Three DNA templates containing poly(A) tail lengths of 60A-G, 95A, or 108A were studied. LC-MS results correlated well with Sanger sequencing, identifying major populations of 60A-G, 95A, or 108A. Surprisingly, unlike Sanger sequencing, LC-MS analysis revealed minor poly(A) populations with lengths longer or shorter than the theoretically encoded poly(A) tail length. This finding could be explained by (i) the slippage of bacterial DNA polymerase I during plasmid replication in bacterial culture, which occurs on repeat mononucleotide sequences, or (ii) the slippage of Q5® High-Fidelity DNA Polymerase during PCR amplification. In conclusion, the method is easy, rapid, and accurate and could replace Sanger sequencing to assess the poly(A) and complementary poly(T) tail lengths in plasmid DNA.

An orthogonal approach for analysis of underivatized steroid hormones using ultrahigh performance supercritical fluid chromatography-mass spectrometry (UHPSFC-MS).

The crucial role of steroid hormones in health and diseases merits their high-throughput, accurate and affordable measurements in biological specimens. Despite advances in analytical methods, sensing and quantifying steroid hormones remains challenging. Immunoassays offer excellent sensitivity but are inherently labour-intensive, costly, and prone to false positives. Mass spectrometry (MS) has been increasingly utilised, with the main hurdle being the isobaric tendencies of similar analytes, which complicates their separation and accurate quantification. This study compares ultrahigh-performance supercritical fluid chromatography separation (UHPSFC) and ultra-high-performance liquid chromatography (UHPLC) for MS detection. It optimises the column chemistry, temperature, and pressure to provide an operational protocol for the resolution and quantification of analytes. It presents the systematic characterisation of UHPSFC-MS performance by investigating spiked blood samples using Solid-Phase Extraction (SPE) and describes the matrix effects associated with MS measurements. Although both separation methods showed adequate resolution, specificity, and retention time, UHPSFC-MS was superior for five out of seven columns tested. With added high-throughput capacities, UHPSFC-MS, thus, offers an optimal solution for the analysis of steroid hormones for research, medical chemistry, and clinical diagnostics.

Tailoring of Novel Ru (III) and Cr (III) Salen Complexes as Catalysts for a Sustainable and Green Synthesis of Dihydro‐tetrazolo [1,5‐a] thiazolo [4,5‐d] pyrimidin‐6‐yl morpholine: Experimental and Theoretical Approaches

ABSTRACTTwo novel Cr (III) and Ru (III) salen complexes based on {3,4‐Bis‐[(5‐chloro‐2‐hydroxy‐benzylidene)‐amino]‐phenyl}‐phenyl‐methanone ligand (CSAB) were synthesized. The complexes were characterized using various spectral and analytical methods. The catalytic performance of the CSAB complexes was investigated via a four‐component condensation reaction involving aromatic aldehydes, rhodamine, morpholine, and 5‐aminotetrazole under mild, environmentally friendly conditions. Different Lewis acids, bases, ionic liquid catalysts, solvents, and catalyst amounts were assessed to optimize the reaction parameters. Both catalyst systems demonstrated robust catalytic activity under strictly managed conditions, with the heterogeneous catalyst CSAB‐Ru showing superior efficacy compared to the homogeneous CSAB‐Cr catalyst. The study confirmed the catalytic capabilities of both complexes and evaluated their recyclability and reusability. The heterogeneous catalyst (CSAB‐Ru) could be reused seven times, whereas the homogeneous catalyst (CSAB‐Cr) could be recycled four times. Both complexes demonstrated strong catalytic activity and selectivity, resulting in high product yields. The study provides insights into the synthetic applications of novel CSAB complexes, highlighting their potential in organic transformations. It emphasizes their ease of use, safety, stability, component availability, quick reaction times, and high yields, making them promising for future industrial applications.

Adaptive algorithms for drone flight control under communication constraints and information incompleteness

Abstract With the rapid increase in the use of drones in various applications, including commercial and governmental, and the increasing probability of communication failures and contingencies, research becomes critical to ensure the safety and efficiency of their operations. The aim of this research is to develop adaptive drone flight control algorithms capable of operating effectively under conditions of limited communication and incomplete information to ensure reliable and safe autonomous operation of these systems. The applied methods include computer modelling and simulation, analytical, statistical, functional, deductive and descriptive methods. The study found that the use of performance evaluation methods for complex systems enables the identification of safety and performance criteria for drones, and drone flight control provides basic principles and methods that can be adapted for drones, including autopiloting and navigation. In addition, analyses of satellite communication and navigation prove the need to consider the limitations of this technology when developing drone control algorithms. The combination of these techniques allows for more robust and adaptive drone control systems that can function effectively in complex environments such as communication limitations and incomplete information. Additionally, it was found that the integration of adaptive control algorithms based on these methods allows drones to effectively adapt to variable environmental conditions and make decisions quickly even when communication is lost or information is limited.

HOW NOT TO DO EUROPEAN INTEGRATIONS: BOSNIA AND HERZEGOVINA AND LEGAL CHALLENGES IN ACCESSION PROCESS TO EUROPEAN UNION

Background: Bosnia and Herzegovina, with its complex constitutional and legal system, is facing many difficulties in its progress toward European Union membership. These challenges have been worsened by political instability, exacerbated by geopolitical shifts in Europe following Russian aggression on Ukraine. Legal complexities in the constitutional order of Bosnia and Herzegovina are often used to halt the country's progress and divert it from its European trajectory. This article analyses the specific instances of very unfavourable legal solutions that are hindering the EU accession process, as well as the recommendations put forth by the EU Commission aimed at removing these legal obstacles. There is an urgent need for reform of constitutional and legal rules to enable the country to effectively continue its EU accession path. The importance of the EU membership perspective for Bosnia and Herzegovina extends beyond simply joining a desirable club of prosperous countries; the reforms required during the EU accession process are needed to strengthen the efficiency of state institutions and secure lasting peace in the country and region. As such, the urgency and potential impact of these proposed legislative changes cannot be overstated. Methods: The research primarily employs a combination of analytical, normative, and comparative methods to examine the legal system and chronology of the integration process. The legal historical method is also used where appropriate. The research focuses on the content of constitutional norms, relevant legislative acts in Bosnia and Herzegovina, and legislative acts of the European Union and other countries. These legislative acts are compared with EU recommendations and legislation from other EU member states to identify the discrepancies. The article provides an overview of the legal framework governing EU integrations in Bosnia and Herzegovina, including norms of international law, constitutional law, national legislation, and EU law that are negatively impacting the EU accession process, and offers certain recommendations for their improvement. Results and conclusions: The research has identified certain norms of constitutional and legislative origin in the legal system of Bosnia and Herzegovina that are harming the country's ability to effectively engage in the EU accession process. Through a normative approach, the article gives recommendations for their improvement, which are in line with the standards set by the institutions of the EU. Amending these problematic legal frameworks would remove their use as political tools aimed at halting the country’s progress in the EU integrations.

Development and Validation of a Stability Indicating Analytical Method for the Estimation of Gliclazide and Sitagliptin in Bulk Drugs and Tablet Dosage Forms by RP-UPLC: An Application of the Quality-by-Design Approach

Sitagliptin and gliclazide are the active ingredients in OpdualagTM. A highly selective DPP-4 inhibitor, sitagliptin is thought to work in type 2 diabetics by delaying the inactivation of incretin hormones, which increases their concentration and lengthens their duration of effect. Sulfonyl urea mostly enhances insulin secretion from pancreatic β-cells by inhibiting ATP-sensitive K+ channels, leading to depolarisation and Ca2+ influx. Reduced serum glucagon levels and enhanced insulin binding to receptors and target tissues are the mechanisms by which it exerts its effects. Objective: This study aims to create and evaluate an RP-UPLC technique for the detection of sitagliptin and gliclazide in pharmaceutical products by applying AQbD principles. Method: Findings By utilising the Design-expert® programme, we were able to execute a central composite design (CCD) consisting of three components arranged in five distinct layers, which greatly improved the chromatographic conditions. One method that oversees the whole analytical procedure life cycle—from method design and optimisation to validation and continual improvement—is Analytical Quality by Design (AQbD). Results: The retention times for sitagliptin were 1.269 minutes and for gliclazide they were 1.572 minutes. The limits of detection (LOD) and quantitation (LOQ) for Sitagliptin and Gliclazide were 0.19 µg/mL, 0.56 µg/mL, 0.28 µg/mL, and 0.86 µg/mL respectively. The recovery percentages for sitagliptin and gliclazide were found to be 99.15% to 100.54% and 99.93% to 100.58%, respectively. Both drugs were found to be susceptible to oxidative and photolytic breakdown in the forced degradation studies. Conclusions A novel RP-UPLC method has been developed for the quantitative detection of sitagliptin and gliclazide in pharmaceutical formulations, utilising the AQbD-based methodology. This approach is straightforward, rapid, precise, particular, and stable-indicating.

Plant-Derived and Synthetic Nicotine in E-Cigarettes: Is Differentiation with NMR Spectroscopy Possible?

To circumvent regulatory frameworks, many producers start to substitute plant-derived nicotine (tobacco-derived nicotine, TDN) by synthetic nicotine (tobacco-free nicotine, TFN) in e-cigarette products. Due to the higher costs of enantiomeric synthesis and purification of TFN, there is a need to develop an analytical method that clearly distinguishes between the two sources. To trace nicotine's origin, its enantiomeric purity can be postulated by 1H NMR spectroscopy using (R)-(-)-1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (BNPPA) as a chiral complexing agent. Low-field (LF) NMR conditions were optimized for this purpose even using a small amount of e-liquid sample (limit of quantification 8 mg/mL nicotine). All investigated products were found to contain one isomer (most likely (S)-(-)-nicotine). A direct 13C NMR method at natural abundance has been validated to differentiate (S)-TDN and (S)-TFN in e-cigarettes produced using nicotine of different origin. The method is based on calculation of the relative 13C content of 10 C-positions of the nicotine molecule with intraday and interday precisions below <0.2%. The method was applied to 12 commercial e-cigarette products labeled as containing TDN and TFN. Principal component analysis (PCA) was applied to the relative peak areas to visualize the difference between studied products. The LF 1H NMR method is a good alternative to expensive high-field NMR to differentiate between a racemate mixture and single optical isomers, whereas only high-precision 13C NMR can be used to distinguish (S)-TDN and (S)-TFN in e-cigarettes after appropriate sample extraction.

EXTRACTION, Extraction, Isolation, Identification and Estimation of Diosgenin by TLC Profiling and UHPLC-LC-SRM Analysis in Three Costus Species

Medicinal plants are utilized for treating many ailments, since ancient times due to their tremendous therapeutic properties. The plant derivatives are used as a raw material for the synthesis of drugs either as a natural or artificial synthetic drug. Costaceae family members are known to possess many medicinal properties few of them are mainly consumed to reduce the blood glucose level and treat many disorders. The sapogenin contained in the rhizome of three Costus species was extracted, identified, and characterized. Young rhizomes were harvested surface sterilized, hydrolyzed; extracted through a soxhlet apparatus and concentrated fractions were subjected to a preliminary phytochemical screening test for saponin, Thin Layer Chromatography, and the UHPLC-MS SRM analysis. The result showed that the maximum yield of the Diosgenin was obtained from the chloroform extract of Costus speciosus. The pharmaceutical analysis in all the three Costus species carried out with isolated saponin was compared with standard Diosgenin. The characterization of isolated diosgenin was done by UHPLC MS and SRM, based on the retention time of all three samples and the comparison with standard Diosgenin. Isolated Diosgenin was quantified through thin layer chromatography with n-hexane: ethyl acetate (7:3) as mobile phase at Rf value of 0.48. The amount of Isolated Diosgenin was estimated by comparing the peak area at a retention time Rt value of 8.5 in all the samples and compared with standard Diosgenin high amount of Diosgenin was found in Costus speciosus rhizome followed by Costus igneus and Costus pictus. The preliminary phytochemical screening and analytical methods involved during the present study were found satisfactory. Thus, the protocol can be used for the extraction of Diosgenin and further used in the synthesis of Drugs. Keywords: Costus pictus, Costus speciosus, Costus igneus, rhizome, TLC, UHPLC-MS, SRM

Enantiomer-Specific Stable Carbon and Nitrogen Isotopic Analyses of Underivatized Individual l- and d-Amino Acids by HPLC + HPLC Separation and Nano-EA/IRMS.

We developed a new method for stable carbon and nitrogen isotopic (δ13C and δ15N) analysis of underivatized amino acid (AA) enantiomers simultaneously, based on high-performance liquid chromatography (HPLC) separation and off-line isotopic measurement. l- and d-Enantiomers of each AA were isolated using a ReproSil Chiral-AA column, purified by wet chemical procedure, and analyzed for δ13C and δ15N values with a nanomol-scale elemental analyzer/isotope-ratio mass spectrometry (nano-EA/IRMS) system. We successfully achieved the separation of l- and d-enantiomers of 15 proteinogenous AAs, with all l-enantiomers eluting before respective d-enantiomers. The δ13C and δ15N values of AA enantiomers were consistent before and after HPLC separation, demonstrating that this analytical method conserves isotopic information. By coupling this column with a multidimensional HPLC system for isolating individual AAs, we analyzed l- and d-AAs in a natural sample, peptidoglycan isolated from Gram-positive bacterium Bacillus subtilis. Results show a surprisingly large 15N-depletion, up to 20‰, in d-glutamic acid relative to its l-counterpart. The first example, to our knowledge, of δ13C and δ15N analyses of underivatized AA enantiomers is expected to contribute to various research areas in the future.

Reflection phenomena of thermoelastic plane waves on a rigid surface within a size-dependent elastic media

The current investigation aims to comprehend the spread of time-harmonic thermoelastic plane waves in an isotropic and homogeneous nonlocal elastic material without bounds, within the framework of the Lord–Shulman model and Eringen’s nonlocal stress model. Our analysis reveals two sets of coupled longitudinal waves and one independent shear-type wave. The coupled longitudinal waves experience dispersion and damping over time due to the dissipative nature of the L-S model. In contrast, the vertically shear-type waves exhibit dispersion characteristics due to the presence of nonlocality in the medium. Furthermore, we observe that the shear-type wave encounters a critical frequency, while the coupled longitudinal waves may face critical frequency conditions under certain circumstances. We explore the reflection of thermoelastic waves at a rigid, thermally insulated, and isothermal boundary of a thermoelastic half-space, particularly in the case of an incident coupled longitudinal thermoelastic wave. We determine the amplitude ratios of the reflected waves to the incident wave through analytical methods. For a specific model, we generate various graphs to analyze the behavior of phase speeds, attenuation coefficients, and reflection coefficients. To assess the impact of the elastic nonlocal parameter on the variations of phase speeds, attenuation coefficients, and amplitude ratios of the reflected waves, we present graphical representations. Notably, our observations indicate that all waves are influenced by the nonlocality of the medium. Longitudinal waves exhibit sensitivity to thermal parameters, whereas the shear-type wave remains independent of thermal effects. Furthermore, the presence of elastic nonlocality results in a reduction in the classical shear-type wave speed.