Magnetic Resonance (MR) rectography in diagnostics of small-size rectal neoplasms

Purpose was the assessment of diagnostic efficiency of MR-rectography in diagnostics of small-size rectal neoplasms. 12 patients with polyps and small tumors of a rectum are examined, the size of detected neoplasms varied in the range 3-18 mm. Native MRI and MRI with retrograde contrasting by ultrasonic gel was carried out. Results of MRI are compared with results of videocolonoscopy. Sensitivity of native MRT was 24%, MR- rectography was 88%. MR-rectography can be used in diagnostics of small-size rectal neoplasms

THE MULTIWAVE IR-SPECTROMETRY AS THE TOOL FOR TOTAL HYDROCARBON ESTIMATIONS

 Problem. To evaluate the total concentration (сΣ) of hydrocarbons (HСs) in natural or waste waters, it is possible to extract all HCs and to measure the generalized analytical signal in the certain IR spectral region. Then the total TPH index (с*) can be determined in terms of the certain standard substance Xst. The error of this estimation δс = (с* - сΣ) / сΣoften exceeds 50 % rel. Specialists believe that the transition to multiwavelength signal measurement using n analytical wavelength values (n 1) improves the accuracy of сΣ estimations. No systematic investigations of this problem were conducted earlier.          Experiment. The model mixtures of alkanes, cycloalkanes and arenes in CCl4 were prepared to simulate the composition of refined extracts. IR-spectra were registered with FT-801 Fourier-spectrometer. The absorbance of each mixture was measured  by three methods: (1) – only with 2930 cm-1; (2) – with 2930, 2960 and 3030 cm-1; (3) – with 2855, 2930, 2960 and 3030 cm-1. The generalized signal was calculated for each mixture by summation of the measurands for different analytical wavelength values (AWV). Corresponding formulae with weighting factors were derived beforehand by the technique of least squares. The total index value (c*) was determined by the calibration curve АΣ= f(сx), and  Simard mixture was used as Xst  in all cases. Calculated δс values for standard methods (1) and (2) were compared with the data obtained using the new method (3). To interpret the results, the absorbance factors were compared for certain individual HCs.           Results. The precision of generalized signals slightly decreases when the number of AWV grows. Simultaneous LODs are raised and the absorbance factors for individual HCs are leveled. The errors of сΣ evaluation via c* for all methods are statistically significant but they diminish when n grows. RMSEP parameter decreases with the methods line (1) (2) (3). Standard methods (1) and (2) do not provide the level of the result accuracy which is necessary according to Russian standards. The new multiwavelength method (3) provides the estimation accuracy which is required. For this method δс values do not exceed 15 % in modulo, even for mixtures with the high content of arenes.Discussion. Our experiment showed that the simultaneous use of some AWVs really provides more reliable сΣ estimations. The main reason for this effect is the leveling of the absorption coefficients for various HCs, particularly for alkanes and arenes. Subsequent reduction of systematic errors may be secured if we will not use the univariate calibration curves.  The multivariate calibration, obtained from the training set of the spectral data (method 3a), leads to accurate сΣ  estimations. In this case δс values do not exceed 8 %, and for the most part of model mixtures systematic errors are not statistically significant. In “Conclusion” the fundamental significances of obtained results and perspectives of their application in aqueous analysis are discussed.            Key words: aqueous analysis, total indices, total content of hydrocarbons, multiwave IR spectrometry, systematic errors(Russian)DOI:http://dx.doi.org/10.15826/analitika.2015.19.1.011S.V. Usova, М.А. Fedorova, S.V. Petrov, V.I. VershininDostoevsky Omsk State University (OmGU), Omsk, Russian Federatio

The multiwave IR-spectrometry as the tool for total hydrocarbon estimations

Проблема. Чтобы оценить суммарное содержание ( с Σ) углеводородов (УВ) в природных или сточных водах, их экстрагируют, измеряют обобщенный сигнал ( А Σ) в ИК-области спектра и находят показатель «содержание нефтепродуктов» ( с *) в пересчете на стандартное вещество Xст. Погрешность определения δс = ( с* - с Σ) / с Σ нередко превышает 50 % отн. Считают, что измерение сигнала при n аналитических длинах волн ( n > 1) повышает точность оценки с Σ, но исследования в этой области не проводились. Эксперимент. Готовили смеси алканов, циклоалканов и аренов в CCl₄, моделируя состав очищенных экстрактов. ИК-спектры регистрировали с помощью фурье-спектрометра FT-801. Поглощение каждой смеси измеряли тремя способами: 1 - при 2930 см⁻¹; 2 - при 2930, 2960 и 3030 см⁻¹; 3 - при 2855, 2930, 2960 и 3030 см⁻¹. Обобщенный сигнал вычисляли, суммируя результаты измерений при разных аналитических длинах волн (АДВ) по заранее выведенным формулам, включающим весовые коэффициенты. Показатель с * рассчитывали по градуировкам вида АΣ = f ( с ₓ); во всех случаях Хст - смесь Симарда. Находили и сравнивали значения δс при разных способах измерения АΣ. Чтобы объяснить выявленные закономерности, сопоставляли удельные коэффициенты поглощения разных УВ для каждого способа измерения А Σ. Результаты. При переходе от одноволновой к многоволновой спектрометрии сходимость результатов незначительно уменьшается, пределы обнаружения УВ растут, а коэффициенты поглощения индивидуальных УВ достоверно сближаются. Значения δс во всех случаях статистически значимы. Обобщающий их параметр RMSEP снижается в ряду (1) > (2) > (3). Методика (3) обеспечивает требуемую стандартами РФ точность оценки с Σ; даже для проб с высоким содержанием аренов δс < 15 % отн. Обсуждение результатов. Эксперимент показал, что одновременное использование нескольких АДВ при измерении аналитического сигнала действительно повышает точность оценки суммарного содержания УВ. Этот эффект объясняется нивелированием чувствительности определения разных УВ, например, алканов и аренов. Дальнейшее снижение погрешностей (при том же наборе АДВ) требует отказа от применения одномерных градуировок вида А Σ = f ( с ₓ). Если применять многомерную градуировку, заранее построенную по спектрам множества модельных углеводородных смесей (методика 3а), значения δс не превышают 8 % отн. В этом случае для большинства модельных смесей систематическая составляющая общей погрешности оказывается статистически незначимой. В « Заключении » охарактеризованы теоретическая значимость полученных результатов и перспективы их использования в гидрохимическом анализе.Problem. To evaluate the total concentration ( с Σ) of hydrocarbons (HСs) in natural or waste waters, it is possible to extract all HCs and to measure the generalized analytical signal in the certain IR spectral region. Then the total TPH index ( с *) can be determined in terms of the certain standard substance Xst. The error of this estimation δ с = ( с* - с Σ) / с Σ often exceeds 50 % rel. Specialists believe that the transition to multiwavelength signal measurement using n analytical wavelength values ( n > 1) improves the accuracy of с Σ estimations. No systematic investigations of this problem were conducted earlier. Experiment. The model mixtures of alkanes, cycloalkanes and arenes in CCl₄ were prepared to simulate the composition of refined extracts. IR-spectra were registered with FT-801 Fourier-spectrometer. The absorbance of each mixture was measured by three methods: (1) - only with 2930 cm⁻¹; (2) - with 2930, 2960 and 3030 cm⁻¹; (3) - with 2855, 2930, 2960 and 3030 cm⁻¹. The generalized signal was calculated for each mixture by summation of the measurands for different analytical wavelength values (AWV). Corresponding formulae with weighting factors were derived beforehand by the technique of least squares. The total index value ( c *) was determined by the calibration curve АΣ = f ( с ₓ), and Simard mixture was used as Xst in all cases. Calculated δ с values for standard methods (1) and (2) were compared with the data obtained using the new method (3). To interpret the results, the absorbance factors were compared for certain individual HCs. Results. The precision of generalized signals slightly decreases when the number of AWV grows. Simultaneous LODs are raised and the absorbance factors for individual HCs are leveled. The errors of сΣ evaluation via c* for all methods are statistically significant but they diminish when n grows. RMSEP parameter decreases with the methods line (1) > (2) > (3). Standard methods (1) and (2) do not provide the level of the result accuracy which is necessary according to Russian standards. The new multiwavelength method (3) provides the estimation accuracy which is required. For this method δ с values do not exceed 15 % in modulo, even for mixtures with the high content of arenes. Discussion. Our experiment showed that the simultaneous use of some AWVs really provides more reliable с Σ estimations. The main reason for this effect is the leveling of the absorption coefficients for various HCs, particularly for alkanes and arenes. Subsequent reduction of systematic errors may be secured if we will not use the univariate calibration curves. The multivariate calibration, obtained from the training set of the spectral data (method 3a), leads to accurate с Σ estimations. In this case δ с values do not exceed 8 %, and for the most part of model mixtures systematic errors are not statistically significant. In “Conclusion” the fundamental significances of obtained results and perspectives of their application in aqueous analysis are discussed

Loss of monocyclic aromatic hydrocarbons during the extraction from the aqueous phase

In order to determine the total content of hydrocarbons (HCs) in natural and waste waters the sum of HCs was extracted, and the possibility of incomplete extraction of most soluble and most toxic HCs – monocyclic arenes – was neglected. The recommendations on the optimal extraction conditions were found to be quite contradictory, while the data for arenes losses was not studied. The purpose of this research was to examine the possibility of quantitative extraction of arenes during HCs determinations. We have measured the extraction degree (R, %) for the most soluble C6 - C9 arenes from model aqueous solutions in optimized conditions by IR and UV spectrometry with hexane and carbon tetrachloride as extractants. The influence of different factors on the extraction degree was investigated. It was established that the optimal phases contact time was 5 minutes. R values for a single extraction made up 30% - 80% depending on the arenes and the extractants nature. The influence of the initial concentration of arenes on R value was not statistically significant. The introduction of salting-out reagents, the increase of extractants volume and the repeated treatment of the sample reduced the losses of arenes, but did not lead to their complete elimination (in all cases R < 90 %). The incompleteness of arenes extraction led to the underestimated results of water analysis. The bigger was the share of arenes in the sum of HCs the bigger was the error value by modulus.Для определения углеводородов (УВ) в природных и сточных водах сумму УВ экстрагируют, пренебрегая потерями наиболее растворимых в воде и самых токсичных УВ – моноциклических аренов. Рекомендации по условиям экстракции противоречивы, потери УВ не изучались. Цель работы – оценить возможность количественного извлечения аренов при определении УВ в водах. Для этого методами ИК- и УФ-спектрометрии определяли степень извлечения (R, %) наиболее растворимых аренов С6 -С9 из модельных водных растворов, используя обычно применяемые экстрагенты (гексан, тетрахлорметан) и варьируя условия экстракции. Установлено, что оптимальное время контакта фаз при извлечении аренов равно 5 минутам. Значения R при однократной экстракции составляют 30-80 % в зависимости от природы арена и экстрагента. Влияние начальной концентрации аренов на величину R незначимо. Введение высаливателей, увеличение объема экстрагента и повторная обработка пробы экстрагентом уменьшают потери, но не приводят к их исключению (во всех случаях R < 90 %). Таким образом, экстракция суммы УВ даже в оптимальных условиях ведет к заниженным результатам анализа. Систематические погрешности будут тем выше (по модулю), чем выше доля аренов в смеси УВ.The paper was written with the financial support of RFBR (RFFI)1 and the Ministry of education and science of Omsk oblast (grant RA 16-43-550479, 2017). The authors express their gratitude to the Senior Doctors of Chemstry V. I. Vershinin, I. V. Vlasova and A. S. Fisyuk for their participation in the discussion of the project, and to the students A. V. Mamontova and D. V. Petrov, who also took part in the experiment

Environmental literacy – as a way of dealing with greenwashing

Статья посвящена проблеме повышения экологической грамотности поселения России. Представлена информация о наиболее авторитетных экологических знаках, описана возможность оценить экологическую маркировку продукции с помощью мобильного приложения «Ecolabel Guide».The article is devoted to the problem of increasing ecological literacy of the Russian settlement. Presents information on the most reputable environmental marks, described the ability to assess the environmental labeling of products using a mobile app «Ecolabel Guide»

Efficiency Assessment of Using Flammable Compounds from Water Treatment and Methanol Production Waste for Plasma Synthesis of Iron-Containing Pigments

This article describes the possibility of applying the low-temperature plasma for obtaining iron-containing pigments from water purification and flammable methanol production waste. In this paper were calculated combustion parameters of water-saltorganic compositions (WSOC) with different consists. Authors determined the modes of energy- efficient processing of the previously mentioned waste in an air plasma. Having considered the obtained results there were carried out experiments with flammable dispersed water-saltorganic compositions on laboratory plasma stand. All the experimental results are confirmed by calculations

Alumosilicate ceramic proppants based on natural refractory raw materials

The sintering-strengthening effect of the additions of the highly ferrous bauxite (with Fe[2]O[3] content of 20-25 % in the calcined state) in the compositions with refractory clays was established. It was found that in the temperature range 1350-1500°C the additions of bauxite in amounts of 10-40% have a fluxing effect due to the iron oxide introduced with bauxite in compositions with clay. An increasing the bauxite additive in the amount of 50-70% ensures its strengthening effect by increasing the total content of the mullite of the prismatic habit in the firing products of composites with clay. Preliminary clay and bauxite calcination at 900 °С and an increase in the content of bauxite additive up to 50-70% in compositions with clay allow to produce aluminosilicate proppants with a bulk density of 1.62-1.65 g/сm{3} and compressive strength up to 52 MPa

CLINICAL AND LABORATORY FEATURES OF THE IMMUNE RESPONSE IN CHILDREN WITH COVID-19 INFECTION

The article presents the results of the analysis of clinical and morphological characteristics and a number of indicators of peripheral blood in children with a new coronavirus infection. The purpose of the study is to give clinical and laboratory characteristics of the immune response in children with a new coronavirus infection. Materials and methods. 102 children with a new coronavirus infection were examined. Evaluation of peripheral blood parameters and lymphocyte subpopulations in children of three age groups 0-4 years, 5-9 years and 10-14 years. Results. In children with a new coronavirus infection, an imbalance of the granulocytic and lymphocytic link is observed, which is most pronounced for children of the younger (0-4 years) and middle (5-9 years) age groups. The general trend of changes is characterized by an increase in lymphocytes and granulocytes at the onset of the disease and a decrease after 2 weeks. The ratio of neutrophils to lymphocytes shows the predominance of neutrophils. Conclusion. The established changes are characterized as specific for most viral infections, but at the same time reflect the pathogenetic specifics of SARS-CoV-2 infection, as a combination of age-related features of the functioning of the immune system and the etiotropic effect of the virus