Linear regression modeling in monitoring tasks based on the method of least absolute deviations

Algorithm for the exact solution of the problem of estimating the parameters of linear regression models by the least absolute deviations method is described. It is based on the descent through the nodal straight lines. This algorithm significantly outperforms other well-known methods of solving the problem and it can be effectively used in practice. The computational complexity of the descent algorithm through the nodal straight lines is assessed. © 2021 Author(s).The research was supported by a grant from the Russian Fund of Fundamental Research, project no. 20-41-660008

Enhancing the performance of the exact algorithm for implementing the method of least absolute deviations when estimating the parameters of linear regression models

An algorithm for finding the exact solution of the problem of estimating the parameters of linear regression models by the method of least absolute deviations is described. This algorithm significantly wins in comparison with the known search algorithm. Comparative characteristics of the proposed and known algorithms are given. An example of practical implementation of the algorithm is described.Описан алгоритм нахождения точного решения задачи оценивания параметров линейных регрессионных моделей методом наименьших модулей. Данный алгоритм значительно выигрывает по сравнению с известным переборным алгоритмом. Приведены сравнительные характеристики предложенного и известного алгоритмов. Описан пример практической реализации алгоритма.Исследование выполнено при поддержке РФФИ, грант № 16-06-00048а

Melanoma epidemiology, prognosis and trends in Latvia

Background Melanoma incidence and mortality rates are increasing worldwide within the white population. Clinical and histological factors have been usually used for the prognosis and assessment of the risk for melanoma. Objectives The aim of the study was to describe the clinical and histopathological features of the cutaneous melanoma (CM) in the Latvian population, to test the association between melanoma features and patient survival, and to assess the time trends for melanoma incidence. Methods We undertook a descriptive, retrospective analysis of archive data of 984 melanoma patients treated at the largest oncological hospital of Latvia, Riga East University Hospital Latvian Oncology Centre (LOC), between 1998 and 2008. Cox proportional hazards model was used to analyse patient survival and autoregressive models were applied to detect trends in melanoma incidence over time for various categories of melanoma. Results The study showed a significant ascending trend in melanoma incidence in Latvia during the time period from 1998 to 2008 (ß = 1.83, 95% CI = 1.15-2.91, P = 0.011). Nodular melanoma was the most common tumour subtype with a frequency of 39.2%. Ulceration was present in 45.2% of melanomas. The mean Breslow thickness was 6.0 mm (6.8 mm) and no significant decline in median Breslow thickness was observed during the study period (P = 0.609). A better overall prognosis was detected for females in comparison with males (HR = 1.49; 95% CI = 1.22-1.81; P < 0.001). Conclusions There is a steady increase in melanoma incidence in Latvia with the majority of melanomas diagnosed at late stages with poor prognosis for survival.publishersversionPeer reviewe

Monitoring the realization degree of the socially responsible marketing policy in the management system of trade enterprises

The present article distinguishes the Ukrainian business-environment’s functioning features, forming the requirements and imposing restrictions on the specific character of the modern conception of the socially responsible marketing realization. The implementation of the socially responsible marketing policy conducted by trade enterprises has been estimated; the comparative analysis of the dynamics of the socially responsible domestic companies’ development, including those with the foreign capital share, has been carried out. It was found that for the last three years the total number of enterprises, implementing the policy of the socially responsible marketing, has not dramatically changed. In 2015, the politicy is being implemented and used mainly by foreign large companies to one extent or another. The positive tendencies and the most problematic aspects in the practice of the socially responsible marketing application have been specified. The analysis of the trade enterprises has also allowed eliciting and systematizing the main objects and target orientation of the socially responsible marketing programs realization: education, health protection, sport, ecology, charity, person’s state of mind, motivation of personnel, feed-back. The possibility to establish the benefit from the realization of the programs in the field of the social marketing has been estimate

УВЭЖХ-МСВР ОПРЕДЕЛЕНИЕ ДАНСИЛЬНЫХ ПРОИЗВОДНЫХ АДРЕНАЛИНА И ДОФАМИНА В СЛЮНЕ ЧЕЛОВЕКА

In the last decade, the quantification of catecholamines in human biological fluids has been of great interest. Changes in catecholamine levels, such as adrenaline and dopamine, in the body lead to neurological disorders as well as several diseases, namely Alzheimer’s and Parkinson’s diseases, neuroendocrine catecholamine - producing tumors - pheochromocytoma, paraganglioma, carcinoid tumors and neuroblastoma. Moreover, different drug combinations can lead to the distortions in the human biological passport, containing the information not only about the erythropoiesis and steroid profile, but also about catecholamine levels, which are difficult to quantify in terms of sample preparation and analysis. A method has been proposed for the determination of adrenaline and dopamine dansyl derivatives in human saliva, including the derivatization and determination of analytes by ultra-high-performance liquid chromatography (UHPLC) with high resolution mass spectrometric detection. The derivatization procedure allowed obtaining less polar catecholamine derivatives, which is especially important for their quantification by reversed-phase ultra-high-performance liquid chromatography since it ensures their better retention on the sorbent. The sensitivity of these substances quantification by the proposed method was estimated; the highest sensitivity was achieved using the mobile phase consisting of the 0.1% formic acid aqueous solution and acetonitrile. The lower limit of quantification was 5 ng/mL for dansyldrenaline and 10 ng/mL for dansyldopamine respectively. The proposed technique was tested on real saliva samples obtained from volunteers to quantify catecholamine dansyl derivatives by reversed-phase high-performance liquid chromatography with high-resolution mass spectrometric detection. High sensitivity of the technique allows using it for adrenaline and dopamine determination in clinical diagnosis.Key words: adrenaline, dopamine, catecholamines, UHPLC-HRMS, saliva, biological fluids, derivatization.DOI: http://dx.doi.org/10.15826/analitika.2020.24.4.004 A.A. Azaryan, E.V. Dmitrieva, A.Z. Temerdashev Kuban State University, Stavropolskaya st., 149, Krasnodar, 350040, Russian FederationВ последнее десятилетие большой интерес вызывает определение катехоламинов в биологических жидкостях человека. Изменение эндогенных уровней таких катехоламинов, как адреналин и дофамин, в организме приводит к неврологическим нарушениям, а также ряду заболеваний, а именно болезни Альцгеймера и Паркинсона, нейроэндокринным катехоламинпродуцирующим опухолям – феохромоцитома, параганглиома, карциноидные опухоли и нейробластома. Кроме того, комбинации различных препаратов, могут приводить к искажениям в биологическом паспорте человека, включающего в себя не только сведения об эритропоезе и стероидном профиле, но и содержании ряда катехоламинов, определение которых также сопряжено с рядом трудностей как в части подготовки проб, так и их анализе. Предложена методика определения дансильных производных адреналина и дофамина в слюне человека, включающая дериватизацию и определение аналитов методом ультравысокоэффективной жидкостной хроматографии с масс-спектрометрическим детектированием высокого разрешения. Проведение процедуры дериватизации позволило получить менее полярные производные катехоламинов, что особенно важно для их количественного анализа в режиме обращенно-фазовой ультравысокоэффективной жидкостной хроматографии, поскольку обеспечивает их лучшее удерживание на сорбенте. Оценена чувствительность определения этих веществ предложенным методом, установлено, что наибольшей чувствительности можно добиться с использованием подвижной фазы, состоящей из 0.1 % водного раствора муравьиной кислоты и ацетонитрила. Нижняя граница определяемых концентраций составила 5 нг/мл для дансиладреналина, 10 нг/мл для дансилдофамина. Предложенная методика апробирована на реальных образцах слюны, полученных от добровольцев с целью установления содержания дансильных производных катехоламинов в режиме обращенно-фазовой высокоэффективной жидкостной хроматографии с масс-спектрометрическим детектированием высокого разрешения. Высокая чувствительность методики позволяет применять ее для определения адреналина и дофамина при клинической диагностике.Ключевые слова: адреналин, дофамин, катехоламины, УВЭЖХ-МСВР, слюна, биологические жидкости, дериватизация.DOI: http://dx.doi.org/10.15826/analitika.2020.24.4.00

Blogger and YouTube services at a distant course “Database management system Microsoft Access”

The article is devoted to the coverage of the course “Database management system Microsoft Access”, an educational blog review “The development of a creative child. ІCТ”, which is used as an auxiliary tool for promoting a course and teacher in the Internet, structural analysis of this blog is made.The channel location is set on YouTube video hosting and how it is used in the course on databases.Attention is drawn to the fact that theoretical and practical material is considered on real, implemented informational and analytical systems.To prepare students for the Olympiadsand provide methodological help teachers of computer science are looking at tasks from databases that were offered at the All-Ukrainian Olympiads on Information Technologies, especiallyII, III and IV stages (offline and online Olympiads), which are located in open access to the blog and YouTube channel. The main focus of the article is devoted to the practical side of teaching teachers of computer science, experience in using the above technologie

ИСПОЛЬЗОВАНИЕ ТВЕРДОФАЗНОЙ ЭКСТРАКЦИИ ДЛЯ ОПРЕДЕЛЕНИЯ ИСПОЛЬЗУЕМЫХ В СПОРТЕ ЛЕКАРСТВЕННЫХ СРЕДСТВ В МОЧЕ ЧЕЛОВЕКА МЕТОДОМ УВЭЖХ-МС/МС

A procedure for the determination of several selective androgen receptor modulators in human urine, namely, Andarine (S-4, GTx-007), Ostarine (S-22, GTx-024, MK-2866) and Ligandrol (LGD-4033, VK-5211), as well as a phytosteroid Laxogenin and Ibutamoren (MK-677), related to non-peptide growth hormone secretagogues, has been developed. Most of these are prohibited by the World Anti-Doping Agency due to their anabolic effects. With the aim of the analytes purification and concentration, a procedure for solid-phase extraction with the use of Varian Bond Elut C8 (100 mg, 1 mL), Biotage Isolute C18 (EC) (100 mg, 1 mL) and Waters Oasis HLB (30 mg, 1 mL) cartridges was applied. To achieve good resolution of the analytes, reversed-phase ultra-high-performance liquid chromatography coupled with the triple quadrupole mass spectrometer as a detector in positive and negative ion detection modes was used. The limits of detection were in the range of 0.1–0.5 ng/mL, limits of quantification were between 0.25–0.5 ng/mL. Calibration curves were examined to be linear in the wide range of concentrations. Matrix effects were also evaluated and were found not to influence the results of the analytes quantification. The proposed method was applied for the analysis of real samples after single 15 mg oral administration of the analytes. All the analytes were positively detected in the human urine samples in 12h, thus, proving the applicability of the procedure for the analytes quantification in the urine.Key words: UHPLC-MS/MS, SARM, Laxogenin, Ibutamoren, solid-phase extraction, doping control DOI: http://dx.doi.org/10.15826/analitika.2018.22.3.008(Russian)E.V. Dmitrieva, A.Z. Temerdashev, A.A. Azaryan, E.M. Gashimova      Kuban State University, Stavropolskaya st., 149, Krasnodar, 350040, Russian Federation Предложена методика определения в моче некоторых селективных модуляторов андрогенных рецепторов, а именно андарина (S-4, GTx-007), остарина (S-22, GTx-024, MK-2866) и лигандрола (LGD-4033, VK-5211), а также фитостероида лаксогенина и ибутаморена (MK-677), непептидого секрета гормона роста, большинство из которых запрещены к употреблению спортсменами Всемирным антидопинговым агентством по причине их анаболического действия. Для очистки и концентрирования аналитов была исследована возможность применения твердофазной экстракции с использованием патронов Varian Bond Elut C8 (100 мг, 1 мл), Biotage Isolute C18 (EC) (100 мг, 1 мл) и Waters Oasis HLB (30 мг, 1 мл). С целью достижения оптимального разделения аналитов использовали обращенно-фазовый вариант ультра-высокоэффективной жидкостной хроматографии с применением тройного квадрупольного масс-спектрометра в качестве детектора в режиме регистрации положительно и отрицательно заряженных ионов. Пределы обнаружения аналитов находятся в диапазоне 0.1–0.5 нг/мл, пределы определения составляют 0.5–2.5 нг/мл. Градуировочные кривые линейны в широком диапазоне концентраций. Проведена оценка матричных эффектов на результаты определения аналитов и показано, что они не оказывают мешающего влияния на результаты определения. Методика была апробирована на реальных образцах мочи после однократного перорального употребления 15 мг действующего вещества. Спустя 12 часов во всех образцах мочи были обнаружены определяемые аналиты, их концентрации лежали в линейном диапазоне градуировочных зависимостей, что свидетельствует о возможности использования предложенной методики для определения исследуемых аналитов в моче человека.Ключевые слова: УВЭЖХ-МС/МС, САРМ, лаксогенин, ибутаморен, твердофазная экстракция, допинг-контроль DOI: http://dx.doi.org/10.15826/analitika.2018.22.3.00