Measurement Standards Research Articles

X-ray polarization measurement of the gold standard of radio-quiet active galactic nuclei: NGC 1068

Context. NGC 1068 is the most observed radio-quiet active galactic nucleus (AGN) in polarimetry, yet its high-energy polarization has never been probed before due to a lack of dedicated polarimeters. Aims. Using the first X-ray polarimeter sensitive enough to measure the polarization of AGNs, we want to probe the orientation and geometric arrangement of (sub)parsec-scale matter around the X-ray source. Methods. We used the Imaging X-ray Polarimetry Explorer (IXPE) satellite to measure, for the first time, the 2–8 keV polarization of NGC 1068. We pointed IXPE at the target for a net exposure time of 1.15 Ms, in addition to using two Chandra snapshots of ∼10 ks each in order to account for the potential impact of several ultraluminous X-ray sources (ULXs) within IXPE’s field of view. Results. We measured a 2–8 keV polarization degree of 12.4% ± 3.6% and an electric vector polarization angle of 101° ± 8° at a 68% confidence level. If we exclude the spectral region containing bright Fe K lines and other soft X-ray lines where depolarization occurs, the polarization fraction rises to 21.3% ± 6.7% in the 3.5–6.0 keV band, with a similar polarization angle. The observed polarization angle is found to be perpendicular to the parsec-scale radio jet. Using a combined Chandra and IXPE analysis plus multiwavelength constraints, we estimated that the circumnuclear “torus” may sustain a half-opening angle of 50–55° (from the vertical axis of the system). Conclusions. Thanks to IXPE, we have measured the X-ray polarization of NGC 1068 and found comparable results, both in terms of the polarization angle orientation with respect to the radio jet and the torus half-opening angle, to the X-ray polarimetric measurement achieved for the other archetypal Compton-thick AGN: the Circinus galaxy. Probing the geometric arrangement of parsec-scale matter in extragalactic objects is now feasible thanks to X-ray polarimetry.

Exploring Degradation in PEM Water Electrolysis Cells Due to Metal Migration: Insights from X-Ray Fluorescence Analysis

Green hydrogen production through proton exchange membrane (PEM) water electrolysis offers a viable renewable energy storage and transport solution. The Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are central to this technology, with the latter’s slow kinetics posing a significant bottleneck. Despite research efforts, iridium (Ir) is the only element which currently meets the stability and activity needs of OER, challenging the search for alternatives and shifting focus towards enhancing catalyst stability [1]. Recent studies have identified metal migration, particularly of Ir, as a critical factor in the degradation of PEM water electrolyzers [2]. This finding has highlighted the importance of understanding metal migration mechanisms and the need to investigate the contribution or interaction of less studied elements such as platinum (Pt), titanium (Ti), and iron (Fe) to the degradation process.This study investigates the migration of both catalytically active (Ir, Pt) and inactive (e.g., Ti, Fe, Ca) metals within PEM water electrolysis membranes, using ex-situ 2D X-ray fluorescence (XRF) mapping (s. Fig. 1). Tests were conducted on PEM water electrolysis single cells (active area: 4 cm2) with a NafionTM 115 catalyst-coated membrane, with anode and cathode loadings of 2.0 mgIr/cm2 and 1.0 mgPt/cm2, respectively. The study entailed varying operating times (10 h, 100 h, 500 h, 1500 h) under constant load, different load profiles (e.g., open-circuit voltage (OCV) and accelerates stress test (AST) phases) for 500 h, and the introduction of specific impurities like iron (Fe) and calcium (Ca) through the anodic feed water. Complementary ICP-MS analysis of the anode and cathode waters was also performed. Selected segments of the catalyst-coated membranes (CCMs) were investigated using synchrotron radiation-based XRF at microXAS beamline (X05LA) of the Swiss Light Source (Paul Scherrer Institute, Villigen, Switzerland) at 11.0, 11.4, and 11.7 keV (below and above the Ir L3- and Pt L3-edges, for IrO2, see e.g. ref. [3]). The beam was focused using a Kirkpatrick-Baez (KB) mirror system. The spatial resolution of the measurements was approx. 1 μm, allowing selective identification and relative concentration of elements to be mapped within the entire cell cross-section (electrodes and polymer layer).Through our XRF analysis, it is possible to detect migration of the catalytically active materials (Ir, Pt) through the Nafion membrane depending on the degradation time. Interestingly, while impurity tests with Ca led to its accumulation in the membrane, Fe impurities introduced similarly did not show significant accumulation. These results, demonstrating the intricate details of metal migration and their varying behaviors under different operational conditions, underscore the value of high-resolution XRF mapping with synchrotron radiation in providing critical insights. This understanding is vital to unraveling the complex degradation mechanisms of PEM water electrolyzers. Further experiments may in principle allow for precise quantification of metal migration, with measurement of appropriate elemental standards. Figure 1. Schematic overview of the study: Catalyst-coated membranes (CCMs) at various stages of degradation are investigated using synchrotron radiation-based X-ray fluorescence (XRF) mapping. This method provides a 2D elemental distribution map, as demonstrated with Iridium (Ir) in this example. Analysis of the cross-sectional distribution of the element within the membrane allows for inferences regarding its migration. We thank the SLS for providing beam-time through an accepted proposal (20221749) and appreciate the micro-XAS beamline team’s help during measurements and data processing.

Evaluating the multiple sulfur isotope signature of Eoarchean rocks from the Isua Supracrustal Belt (Southwest-Greenland) by MC-ICP-MS: Volcanic nutrient sources for early life.

On the anoxic Archean Earth, prior to the onset of oxidative weathering, electron acceptors were relatively scarce, perhaps limiting microbial productivity. An important metabolite may have been sulfate produced during the photolysis of volcanogenic SO2 gas. Multiple sulfur isotope data can be used to track this sulfur source, and indeed this record indicates SO2 photolysis dating back to at least 3.7 Ga, that is, as far back as proposed evidence of life on Earth. However, measurements of multiple sulfur isotopes in some key strata from that time can be challenging due to low sulfur concentrations. Some studies have overcome this challenge with NanoSIMS or optimized gas-source mass spectrometry techniques, but those instruments are not readily accessible. Here, we applied an aqua regia leaching protocol to extract small amounts of sulfur from whole rocks for analyses of multiple sulfur isotopes by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Measurements of standards and replicates demonstrate good precision and accuracy. We applied this technique to meta-sedimentary rocks with putative biosignatures from the Eoarchean Isua Supracrustal Belt (ISB, >3.7 Ga) and found positive ∆33S (1.40-1.80‰) in four meta-turbidites and negative ∆33S (-0.80‰ and -0.66‰) in two meta-carbonates. Two meta-basalts do not display significant mass-independent fractionation (MIF, -0.01‰ and 0.16‰). Insitu Re-Os dating on a molybdenite vein hosted in the meta-turbidites identifies an early ca. 3.7 Ga hydrothermal phase, and insitu Rb-Sr dating of micas in the meta-carbonates suggests metamorphism affected the rocks at ca. 2.2 and 1.7 Ga. We discuss alteration mechanisms and conclude that there is most likely a primary MIF-bearing phase in these meta-sediments. Our new method is therefore a useful addition to the geochemical toolbox, and it confirms that organisms at that time, if present, may indeed have been fed by volcanic nutrients.

Precise lateral measurements of step height standards using Hamming area model

Since the ISO 5436 profile analysis presents the axial measurements of the step height/depth standards and does not present a direct method for the lateral measurements, a new method based on the Hamming area model for the lateral measurements of step height/depth standards is presented. The basic idea of the method is to mimic the experimental profile of the step height/depth by a combination of the Hamming window pass-band filter and the RMS model. The lateral position of the 50 % height/depth value of the mimicked Hamming height/depth is assigned. The areas up and down the assigned value are then computed and compared for the lateral measurements of the step height/depth standard. The method is applied for the lateral measurements of a groove structure of a transparent step depth standard. The results show that the total area included in the right line edge of the groove structure is greater than the total area included in the left line edge by 151.66 nm. The error in area measurement is computed to be 1.7 %. The proposed method can be applied to any step height/depth regardless of its height/depth, width, and sharpness of the line edges.

Measurement of EELS standards and application on oxidation state determination of a MeOH catalyst

Measurement of EELS standards and application on oxidation state determination of a MeOH catalyst

Improvements in the determination of attogram-sized 231Pa in dissolved and particulate fractions of seawater via multi-collector inductively coupled plasma mass spectrometry

A technique is developed to quantify the ultra-trace 231Pa (35–3904 ag) concentration in seawater using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The method is a modification of the process developed by Shen et al. (Anal Chem 75(5):1075–1079, 2003. https://doi.org/10.1021/ac026247r) and extends it to the application of very low levels of actinides, and the 35 ag 231Pa can be measured with a precision of 15%. The total process blank for the water column was 0.02 ag/g, while the values of the large and small particles were ~ 30 ag/g. The ionization efficiency (ions generated/atom loaded) varies from 0.7 to 2.4%. The measurement time is 2–5 min. The amount of 231Pa needed to produce 231Pa data with an uncertainty of ± 0.8–15% is 35–3904 ag (~ 0.9 × 105 to 10 × 106 atoms). Replicate measurements of known standards and seawater samples demonstrate that the analytical precision approximates that expected from counting statistics, and that based on detection limits of 52 ag, 55 ag, and 28 ag, protactinium can be detected in a minimum seawater sample size of ~ 2.6 L for small suspended particulate matter (> 0.8 μm and < 51 μm), ~ 3.0 L for large suspended particulate matter (> 51 μm), and ~ 56 mL for filtered (< 0.45 μm) seawater. The concentration of 231Pa (several attograms per liter) can be determined with an uncertainty of ± 2–8% (2σ) for suspended particulate matter filtered from ~ 60 L of seawater. For the dissolved fraction, ~ 1 L of seawater yields 231Pa measurements with a precision of 0.8–10%. The sample size requirements are several orders of magnitude less than traditional decay-counting techniques, and the precision is better than that previously reported for ICP-MS techniques. Our technique can also be applied to other environmental samples, including river, lake, and cave water samples.

Connector effects and reference plane influence in the N-Type connector

In this paper we outline the impact of mixing slotted N-type and slotless N-type connectors during a vector network analyzer calibration. We want to point out that making precise measurements of typical transfer standards, while using both N-type jack connectors is very difficult, because of the reference plane shift. We performed simulations of the two connector jack geometries to estimate the impact on measurements of devices under test with either plug or jack interface. The influence of mixing slotted and slotless connectors is then validated through simple measurements, which can be easily repeated in many labs. The results show that mixing of slotted and slotless jacks adds errors in the same order of magnitude sometimes reported as measurement uncertainties by national metrology institutes.

TERRITORIAL POLICY OF THE EU STATES: TARGETS, TOOLS, ACHIEVEMENTS

The article presents the process of formation and development of the territorial policy of the European Union and its Member States. The author defines the goals and logic of territorial and political transformation of national territorial and political systems in the context of glocalisation – macro-regional integration of national entities in Europe, where regions are proclaimed the main beneficiary of reforms, and place is proclaimed the topos, the basis of the political process. Place-based politics, development of self-government systems, decentralisation reforms, promotion of local and regional autonomy and systemic asymmetry, where status is determined by the scope of functional responsibilities, are considered as processes of de(re)construction of a new model of polycentric governance and political interaction in the context of formation of an effective supranational political space of the EU. The author examines the peculiarities of the transformation of systemic relations in the EU member states, including the relations between metropolises and non-European remote territories (on the example of France and the Netherlands), and the relations between the supranational centre of the EU and these remote territories of the EU states, which have the specifics of asymmetric involvement in the territorial and political processes of the EU. The author notes that the development of the EU political space is ahead of the process of transformation of the territorial morphology, which is manifested in the expansion of political participation rights at the supranational level and the preservation of restrictions at the national level. The paper notes that the EU’s spatial development strategy is formed on the basis of an institutional compromise between different levels of political decision-making in a multi-level and polycentric system of territorial and political relations and is provided by a set of instruments. This complex is formed by: the policy of vertical and horizontal cooperation; multilevel and polycentric governance; practices of regional and autonomy; asymmetry of statuses and functional roles; 4D decentralisation instruments; standardisation and measurement (indexation) of standards; instruments of consociative democracy, which provide for “inclusion policy”, “effective citizenship”, “mobile political participation” in the context of deepening integration, increasing mobility, and changing the functional significance of the institution of citizenship.

Comparison of Raman spectral characteristics and quantitative methods between 13CH4 and 12CH4 from 25 to 400 °C and 50 to 400 bar

In recent years, increasing attention has been given to quantifying the isotopic compositions of gases by Raman spectroscopy. However, related research on the carbon isotopes of CH4 is still lacking. In this study, the Raman spectral characteristics of 13CH4 and 12CH4 in the pure CH4 system and in the CH4–H2O system are comprehensively studied at temperatures ranging from 25 to 400 °C and pressures ranging from 50 to 400 bar. For the pure CH4 system, the peak positions of the symmetric stretching band (ν1) of 13CH4 and 12CH4 both shift to a higher wavenumber with increasing temperature and decreasing pressure, and their full width at half maximum (FWHM) values can reach 4.7 cm−1 and 5.5 cm−1, respectively, with increasing temperature and density. The peak position of the ν1 band of 13CH4 is always 4.6–5.1 cm−1 lower than that of 12CH4 under the same conditions, indicating that 13CH4 and 12CH4 can be distinguished by peak position and FWHM in the Raman spectra. Although the calculated Raman shifts (ν0) at zero-density for 13CH4 and 12CH4 are different, the unified equation for determining the density of CH4-rich fluid inclusions is still applicable, as long as to bracket the sample measurement with measurements of reference standards. For the CH4–H2O system, the peak position of the ν1 band of dissolved 13CH4 is approximately 2.5 cm−1 lower than that of 12CH4, while their FWHM values can be more than 12.2 cm−1, causing more difficulty in distinguishing them in aqueous solutions. In addition, Raman quantitative calibration models of 12CH4 and 13CH4 in the CH4–H2O system are established. The difference in the Raman scattering cross section (RSCS) of dissolved 12CH4 and 13CH4, rather than changes in the molar density or RSCS of water is the main reason leading to the difference in the Raman quantitative calibration models of CH4 concentrations between the 12CH4–H2O system and the 13CH4–H2O system. Our work provides a good reference for the in situ identification and quantification of the carbon isotopic composition of CH4 in high-temperature and high-pressure environments.

Spoilage markers for freshwater fish: A comprehensive workflow for non-targeted analysis of VOCs using DHS-GC-HRMS

Changes of volatile organic compounds (VOCs) patterns during 6 days of storage at +4 °C were investigated in different freshwater fish species, namely carp and trout, using dynamic headspace gas chromatography time-of-flight mass spectrometry (DHS-GC-TOFMS). DHS parameters were systematically optimized to establish optimum extraction and pre-concentration of VOCs. Moreover, different sample preparation methods were tested: mincing with a manual meat grinder, as well as mincing plus homogenization with a handheld homogenizer both without and with water addition. The addition of water during sample preparation led to pronounced changes of the volatile profiles, depending on the molecular structure and lipophilicity of the analytes, resulting in losses of up to 98 % of more lipophilic compounds (logP > 3).The optimized method was applied to trout and carp. Trout samples of different storage days were compared using univariate (Mann-Whitney U test, fold change calculation) and multivariate (OPLS-DA) statistics. 37 potential spoilage markers were selected; for 11 compounds identity could be confirmed via measurement of authentic standards and 10 compounds were identified by library spectrum match. 22 compounds were also found to be statistically significant spoilage markers in carp. Merging results of the different statistical approaches, the list of 37 compounds could be narrowed down to the 14 most suitable for trout spoilage assessment.This study comprises a systematic evaluation of the capabilities of DHS-GC coupled to high-resolution (HR) MS for studying spoilage in different freshwater fish species, including a comprehensive data evaluation workflow.

An Exploration of Australian Online Government Portals for Women Experiencing Domestic Violence During the COVID-19 Pandemic.

Domestic violence against women increased during COVID-19 lockdowns. This inaugural study examined the content of Australian government online portals, for women seeking support and help for domestic violence, during the 2021 COVID-19 pandemic. This mixed methods study incorporated four phases: a search; measurement of portal quality standard using DISCERN; enumeration of portal items; and a qualitative exploration of portal text. Australian governments must continue to work alongside domestic violence services as we found some portals were better than others. Continued review, revision, and funding are needed to meet the demands associated with this evolving public health emergency.

Estimation of dihydroartemisinin in human plasma using a highly sensitive LTQ Orbitrap mass spectrometer with Xcalibur software.

Background: Artemether (ARM), the O-methyl ether prodrug of dihydroartemisinin (DHA), is considered a first-line antimalarial agent. Artemether is extensively metabolized in vivo to its active metabolite DHA, and therefore its determination offers considerable difficulties. In the present study, DHA identification and estimation were accurately performed by the mass spectrometric analysis, using a high-resolution liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) LTQ Orbitrap hybrid mass spectrometer. Methods: The plasma samples were taken from healthy volunteers, and the spiked plasma was extracted by adding 1mL of a mixture of dichloromethane and tert.-methyl butyl ether (8:2v/v) to 0.5mL of plasma. The internal standard solution (artemisinin 500ng/mL) was added to the plasma samples. After vertexing and centrifugation, the organic layer was separated and transferred into another tube and dried under nitrogen. The residue was reconstituted in 100μL of acetonitrile and was injected onto the LC-MS system for analysis. Measurement of standards and samples was carried out isocratically on a Surveyor HPLC system combined with an LTQ Orbitrap mass spectrometer using an ACE 5 C18-PFP column. Mobile phase A consisted of 0.1% v/v formic acid in water, Mobile phase B consisted of acetonitrile only, and isocratic elution was carried out with A:B 20:80, v/v. The flow rate was 500μL/min. The ESI interface was operated in a positive ion mode with a spray voltage of 4.5kV. Results: Artemether is not a very biologically stable compound and is immediately metabolized to its active metabolite dihydroartemisinin, so no clear peak was observed for artemether. Both artemether and DHA after ionization undergo neutral losses of methanol and water, respectively, in the source of the mass spectrometer. The ions observed were (MH-H2O) m/z 267.15 for DHA and (MH-m/z 283.15 for internal standard artemisinin. The method was validated according to international guidelines. Discussion: The validated method was applied successfully for the determination and quantification of DHA in plasma samples. This method works well for the extraction of drugs, and the Orbitrap system with the help of Xcalibur software accurately and precisely determines the concentration of DHA in spiked as well as volunteer's plasma.

АНАЛІЗ ВИКОРИСТАННЯ ДИСТАНЦІЙНОГО ФОРМАТУ НАВЧАННЯ ПРИ ВИКЛАДАННІ ДИСЦИПЛІНИ «ВЗАЄМОЗАМІННІСТЬ, СТАНДАРТИЗАЦІЯ І ТЕХНІЧНІ ВИМІРЮВАННЯ» ЗА ДОПОМОГОЮ GOOGLE FORMS

The article analyzes the experience of implementing training using remote components in teaching the discipline "Interchangeability, standardization and technical measurements" at the Odesa National Maritime University (ONMU) during the pandemic and the effect of the legal regime of martial law in Ukraine in order to find effective ways to improve the educational process. The study of the problems of education development using distance forms of education continues and has become even more relevant not only in connection with the COVID-19 pandemic, but also with the special conditions of today - the state of war in Ukraine. In just a few years, advances in technology, the COVID-19 pandemic, and martial law in Ukraine have revolutionized traditional education systems and fundamentally changed the scope of virtual and online learning in higher education institutions, primarily in ONMU. Modern trends require a rethinking of the basic processes of training future specialists. With distance learning, fundamentally new learning models are introduced into the educational process, which include holding conferences, independent work of students with information fields from various knowledge banks, project work, trainings and other types of activities with computer technologies. The source of information in these models are databases in the virtual learning environment, the coordinator of the learning process is the teacher, and the interpreter of knowledge is the student. Thus, the student's activity changes in the direction from acquiring knowledge to searching for it. Having considered the pros, cons and risks of such training formats, using his experience, a professional teacher will skillfully choose a type of activity that will allow the effective application of each of these training modes. Teachers: associate professors Pizintsali L.V. and Rossomakha O.I. improved professional competence through participation in an online seminar organized within the framework of cooperation between Google Ukraine and the Ministry of Education and Science of Ukraine. The teachers used this experience to determine the students' opinion about the mode of learning using remote components and to further improve the method of conducting classes. According to the results of the survey, the authors of the article claim that it is necessary to work on the improvement of education using the distance format and the development of online educational platforms in the long term, and its perception as temporary, for the period of martial law, is erroneous.

Using a mobile application to teach students to measure with a micrometer during remote laboratory work

In modern conditions, the transition to distance learning has set new tasks for teachers, in particular, related to laboratory work. In these works, students not only study the structure and features of special equipment, but also acquire practical skills in working with the tool. The purpose of the article is to present our own experience of developing and using in the educational process a mobile application for teaching micrometer measurements during the relevant remote laboratory work in the disciplines ``Interchangeability, Standardization and Technical Measurements'' and ``Physics''. The literature analysis showed that ICT is widely used in the educational process in higher education, but computer programs and mobile applications are usually developed for secondary school disciplines, so there was a need to develop an information program for teaching students in distance learning, in particular during laboratory work. In order to teach students to work with a micrometer during distance learning, we have developed a mobile application. The process of developing the application included modeling the micrometer in the CAD system, creating training scenes in the Unity game engine and writing scripts to fully immerse students in the learning process. The mobile application developed by us consists of three parts: theoretical, educational and practical. In the theoretical part, students learn the structure and principles of working with a micrometer. The training part is developed in the form of a video lesson of working with the equipment. The practical part contains an electronic model of the micrometer and allows you to make measurements. Thus, during distance learning using the developed application, the percentage of qualitative success of students in laboratory work on the topic ``Measuring parts with a micrometer'' increased by 7.3\% compared to the same period of distance learning without the use of this application.

Practical revision of error separation technique to improve cylindricity measurement

Theoretic aspects of error separation techniques or reversal methods are widely described in literature to remove the instrument component and isolate the desire characteristic. However, the mathematical step by step procedure strongly depend of the measurand and measurements; and is not frequently found. This paper proposes an approach to design and process cylindricity measurements of cylindrical standards, through an error separation technique; given a detailed mathematical development and assumptions, and the impact of the later ones in the measurement uncertainty. Also, an analysis of the uncertainty estimation budget is made, through which the improvement of the method can be observed.

Equilibrated Gas and Carbonate Standard-Derived Dual (Δ47 and Δ48) Clumped Isotope Values.

Carbonate clumped isotope geochemistry has primarily focused on mass spectrometric determination of m/z 47 CO2 for geothermometry, but theoretical calculations and recent experiments indicate paired analysis of the m/z 47 (13C18O16O) and m/z 48 (12C18O18O) isotopologues (referred to as and ) can be used to study non-equilibrium isotope fractionations and refine temperature estimates. We utilize 5,448 and 3,400 replicate measurements of carbonate samples and standards, and 183 and 195 replicate measurements of gas standards from 2015 to 2021 from a multi-year and multi-instrument data set to constrain and values for 27 samples and standards, including Devils Hole cave calcite, and study equilibrium -, -temperature, and -temperature relationships. We compare results to previously published findings and calculate equilibrium regressions based on data from multiple laboratories. We report acid digestion fractionation factors, and , and account for their dependence on the initial clumped isotope values of the mineral.

Construction and Measurement of High Quality Livelihood Security Standards of Multi-level Social Security System in Ethnic Areas under the Goal of Common Prosperity: A Survey Based on Ethnic Areas in Gansu

Construction and Measurement of High Quality Livelihood Security Standards of Multi-level Social Security System in Ethnic Areas under the Goal of Common Prosperity: A Survey Based on Ethnic Areas in Gansu

EURAMET supplementary comparison EURAMET.L-S26.1, measurement of groove depth standards in the range 5 μm up to 0.9 mm

Main textIn this supplementary comparison depths of six v-shaped grooves with nominal values 5/20/50/200/600 and 900 μm were measured. The depths were measured according to ISO 5436-1. The PTB nickel depth setting standard was used as reference standard. PTB and MIKES measures all depths, CEM 2 and UME 3 larger depths. The results with associated uncertainties were in agreement.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Development and validation of reliable astaxanthin quantification from natural sources.

Astaxanthin derived from natural sources occurs in the form of various esters and stereomers, which complicates its quantitative and qualitative analysis. To simplify and standardize astaxanthin measurement with high precision, an enzymolysis-based astaxanthin quantification method was developed to hydrolyze astaxanthin esters and determine free astaxanthin in all its diastereomeric forms. Astaxanthin standards and differently processed Haematococcus pluvialis biomass were investigated. Linear correlation of standards of all-E-astaxanthin was observed in a measurement range between extract concentrations of 1.0 μg/mL and 11.2 μg/mL with a coefficient of variation below 5%. The diastereomers 9Z-, and 13Z-astaxanthin, and two di-Z-forms were detected. In contrast to the measurement of standards, the observed measurement range was extended to 30 μg/mL in extracts from H. pluvialis. The nature of the sample had to be taken into account for measurement, as cell, respectively, sample composition altered the optimal concentration for astaxanthin determination. The measurement precision of all-E-astaxanthin quantification in dried H. pluvialis biomass (1.2-1.8 mg dried biomass per sample) was calculated with a coefficient of variation of maximum 1.1%, whereas it was below 10% regarding the diastereomers. Complete enzymolysis was performed with 1.0 to 2.0 units of cholesterol esterase in the presence of various solvents with up to 2.0 mg biomass (dry weight). The method was compared with other astaxanthin determination approaches in which astaxanthin is converted to acetone in a further step before measurement. The developed method resulted in a higher total astaxanthin recovery but lower selectivity of the diastereomers. The reliability of photometric astaxanthin estimations was assessed by comparing them with the developed chromatographic method. At later stages in the cell cycle of H. pluvialis, all methods yielded similar results (down to 0.1% deviation), but photometry lost precision at earlier stages (up to 31.5% deviation). To optimize sample storage, the shelf life of astaxanthin-containing samples was investigated. Temperatures below -20°C, excluding oxygen, and storing intact H. pluvialis cells instead of dried or disrupted biomass reduced astaxanthin degradation.

ВИКОРИСТАННЯ ІНФОРМАЦІЙНИХ ТЕХНОЛОГІЙ У ПРОФІЛЬНІЙ ПІДГОТОВЦІ СТУДЕНТІВ ІНЖЕНЕРНО-ПЕДАГОГІЧНИХ СПЕЦІАЛЬНОСТЕЙ

The article deals with the problem of using information technologies in the process of specialized training of students of engineering and pedagogical specialties. The aim of the article is to reveal the essence and peculiarities of the use of information technology in the training of future vocational teachers; to identify the problems of classical teaching methods and to find ways to solve them through the use of information technology. A set of research methods was used, namely: content analysis, generalization and specification of the provisions of the Standards of Higher and Vocational Education of Ukraine, educational programs and curricula, designing the content and structure of an e-learning course, substantiation of the conditions for using e-learning courses in the process of specialized training of students. Results of the study. The Standard of Higher Education of Ukraine, specialty 015 Vocational Education (by specialization), first (bachelor) level, was analyzed. The existing curricula for the training of vocational teachers of transport profile were examined for their compliance with the requirements of educational standards. It has been determined that the normative part of the curriculum includes cycles of general and professional training which contain blocks of fundamental, psychological, pedagogical and methodological, scientific and subject, and practical training. It has been found out that the courses that form the special competencies of vocational teachers of transport profile belong to the block of scientific and subject training. The courses that form the special competencies of transport vocational teachers are highlighted, namely: vehicles and their maintenance, transport logistics, electrical and information-computer systems in transport, traffic rules, operation and repair of transport machine engines, interchangeability, standardization and technical measurements, and technical mechanics. Traditional approaches to the study of these courses are investigated in order to identify the main shortcomings. It has been stated that the traditional methodology of conducting classes involves significant time spent on note-taking of educational material, which can be mastered with greater efficiency using information and communication tools. Ways to eliminate the shortcomings of traditional approaches to the study of specialized courses are proposed, one of which is the development and implementation of e-courses on the Moodle platform, since this platform allows combining different formats of information, makes it possible to timely update the educational material in accordance with the pace of development of the transport industry, as well as it is easy to use and supported by most modern Smart devices. The structural and functional components of the e-learning course are defined including an information and organizational component; a training component; an information and reference component; and a practical component. The requirements for creating and implementing e-learning courses in the educational process are generalized. An e-learning course on the Moodle platform in the Transport Logistics course has been developed. It consists of information and methodological, training, control and evaluation, and reference blocks. A description of the content of these structural blocks is presented. Prospects for further research are identified; these are development of methods for using e-learning courses in specialized subjects in a mixed form of education under martial law.