The study of oscillations of a rotor at the collision with a stator based on the quasidiagonalistic method

The method of quasidiagonalization which is developed for linear dynamic systems is used for solving a nonlinear problem of a rotor’s collision with a stator in a turbine. This method is based on submitting the solution in the form of two addendums (a quasistatic solution and a dynamic one). The quasistatic solution is calculated from some simplified equations. The dynamic solution is found for the following forms of oscillations: their natural frequencies are in a certain frequency range, which is consistent with the external impact. Consequently, a system of equations with significantly lower dimension is used for calculating the dynamic constituent

Mobile applications as a promotional tool of a tourist offer in protected areas

The rapid development of information and communications technology (ICT) in recent decades has resulted not only in drastic increase in speed of the information flow, but also in the number of users of mobile devices. This trend has been recognized and used by many industries, including tourism. The use of specialized application software, compatible with the modern 'smartphones', the interaction between tourists and tourist destinations received a whole new dimension. This article aims at analyzing the ways in which the two seemingly incompatible concepts - tourism in protected nature and advanced communication technologies - can complement each other in order to create, improve and promote ecotourism products. Furthermore, it will analyze the latest trends in the development of mobile applications used in tourism industry and present examples of good practice in protected areas in Serbia and abroad. Due to the fact that mobile applications and technological innovations are relatively new and so far very few re­searchers have involved in the research of their effects on the users' satisfaction and their behavior, this paper will give guidelines for future research on this topic

OPTIMAL SEISMIC PROTECTION OF STRUCTURES ON BEARINGS WITH BILINEAR HYSTERETIC CHARACTERISTIC

The design of optimal seismic protection systems on bearings with hysteresis behavior leads to a conditional multidimensional global optimization problem with a nonlinear and non-differentiable objective function. In this paper, bearings with bilinear characteristic with hysteresis are considered, i.e. for each nonlinear bearing there are four parameters to optimize: ultimate elastic displacement and stiffness for the elastic mode and ultimate displacement and stiff-ness for the inelastic mode. We study the seismic response of an elastic beam on four nonlinear bearings under vertical seismic ground motion. The perturbation functional as an integral of the quadratic form of the state vector with a weight matrix formed from the stiffness and inertia matrices of the system on equivalent elastic supports is considered as the objective function. Minimization of the functional means the minimum of the total energy of the system on equivalent elastic bearings. Genetic algorithm is used to solve the optimization problem

Real-Time and On-Line Near-Field Microwave Inspection of Surface Defects in Rolled Steel

The potential and limitations of near-field microwave inspection techniques for detecting various surface defects in rolled steel have been investigated. The focus of this study has been to investigate this potential for tin mill products containing gross and subtle defects including steel induced defects, roll marks, holes, scratches and gouges

The Procedure of Electrochemical Microbiological Assay for Comparative Analysis of the Properties of Various Plant Extracts

В последнее время в пищевой, фармацевтической, косметической и иной продукции, производимой и потребляемой человеческим обществом, ощущается всё больший недостаток биологически активных веществ (БАВ) природного происхождения, одним из наиболее приемлемых и распространённых источников которых являются различные растительные экстракты (РЭ). Кроме того, всё более актуальной становится проблема разработки достаточно объективных и в то же время экспрессных и доступных для широкого применения методов количественной оценки про- и антибиотических свойств большого количества образцов как новой, так и уже допущенной к применению продукции. Целью настоящего исследования стала доработка и апробирование экспрессной и объективной инструментальной методики оценки про- и антибиотических свойств продукции, включающей различные растительные экстракты, с последующим анализом влияния указанных экстрактов на динамику биохимической активности типичных представителей микробиоты и патогенной микрофлоры человека. Предложена методика микробиотестирования, предусматривающая периодическую (через каждые 2 ч) регистрацию изменений рН, редокс-потенциала (Eh) и электропроводности жидкой питательной тестовой среды (ТС), засеянной жизнеспособными тестовыми микроорганизмами (ТМ) и инкубируемой в присутствии и в отсутствие тестируемых образцов (ТО). С помощью указанной методики был проведён сравнительный анализ про- и антибиотической активности в отношении Escherichia сoli, Lactobacillus acidophilus и Staphylococcus aureus разных концентраций цельных докритических экстрактов, получаемых с помощью сжиженного СО2 из 10 разных видов растительного сырья. Проведённые исследования показали, что среди ТО наиболее активные пролонгированные антимикробные свойства проявили экстракты из травы полыни таврической (Artemisia taurica) и багульника болотного (Ledum palustre), а также корней аира болотного (Acorus calamus) при их концентрациях в ТС от 3 об.% и выше; а наиболее активные пролонгированные пребиотические свойства проявили экстракты из ягод можжевельника обыкновенного (Juniperus communis), корней девясила высокого (Inula helenium) и аира болотного (Acorus calamus), а также листьев тысячелистника обыкновенного (Achillуea millefolium) при их концентрациях в ТС равных 0,2 об.%. Начальная биологическая активность ТО в большинстве случаев была больше их пролонгированной активности. В то время как среднесрочная (по времени взаимодействия ТО с ТМ) антибиотическая активность ТО, как правило, была промежуточной по величине между их начальной и пролонгированной активностью. Таким образом, очевидно, что биологическая активность продукции, включающей РЭ, в значительной степени определяется не только составом присутствующих в этой продукции БАВ, но и их концентрацией, а также временем взаимодействия с живыми организмами (такими, как сам человек, его микробиота и т.п.) и другими факторами. Причем точный характер этих зависимостей в большинстве случаев может быть установлен лишь эмпирически, с помощью значительного числа тестовых испытаний, которые удобно проводить с помощью представленной в этой работе методики, позволяющей более экспрессно, объективно и информативно, а также менее трудоёмко и материалоёмко, чем при использовании стандартных микробиологических методов, оценивать влияние на динамику жизненной активности микроорганизмов (которая, как показано в работе, достоверно коррелирует с их биохимической активностью) различных образцов пищевой, фармацевтической, косметической и иной продукции, а также отдельных ингредиентов и добавок к нейRecently, the content of biologically active substances (BAS) of natural origin in food, pharmaceutical, cosmetic, and other products manufactured and consumed by humans has been steadily decreasing. Among the most acceptable and common sources of such BAS are various plant extracts. Moreover, the problem of developing sufficiently objective and at the same time rapid and widely applicable methods for quantitative assessment of pro- and antibiotic properties of a large number of products, both new and already approved for use, is becoming increasingly urgent. Thus, the purpose of this study was 1) to develop a rapid and objective instrumental method for assessing pro- and antibiotic properties of various samples of food, pharmaceutical, cosmetic, and other products and 2) to analyze the influence of various plant extracts on the biochemical activity of typical representatives of human microbiota and pathogenic microflora by using this method. The bioassay procedure has been developed, which includes periodic (every 2 h) recording of changes in pH, redox potential, and electrical conductivity of a liquid nutrient test medium (NTM) inoculated with viable test microorganisms (TM) and incubated in the presence and absence of test samples (TS). This procedure was used to conduct comparative analysis of the pro- and antibiotic activity of different concentrations of subcritical whole extracts prepared from 10 different types of plant raw materials using liquefied CO2 against Escherichia coli, Lactobacillus acidophilus, and Staphylococcus aureus. The study shows that among the TS, the most active long-term antibiotic properties are exhibited by extracts of wormwood (Artemisia taurica) and wild rosemary (Ledum palustre) leaves and marsh calamus (Acorus calamus) roots at NTM concentrations of 3 vol.% or higher. The most active long-term probiotic properties were exhibited by extracts of common juniper (Juniperus communis) berries, elecampane (Inula helenium) roots, calamus (Acorus calamus) roots, and yarrow (Achilluea millefolium) leaves at NTM concentrations of 0.2 vol.%. The initial biological activity of most TS was greater than their long-term activity. At the same time, the mid-term (relative to the TS/TM interaction time) antibiotic activity of most TS was intermediate between their initial and long-term activity. Thus, it is obvious that the biological activity of food and other products containing various plant extracts is determined not only by the BAS composition of the product but also by the concentration of the extract in the product, the time of its interaction with living organisms (humans, their microbiota, etc.), and other factors. Moreover, the exact nature of these relationships in most cases can be established only empirically, by performing a considerable number of tests. These tests can be conveniently carried out using the procedure described in this work, which is less labor- and material-intensive than conventional microbiological methods. This procedure gives much more rapid, objective, and informative assessments of the effects of various samples of food, pharmaceutical, cosmetic, and other products and individual ingredients and additives on the dynamics of the vital activity of microorganisms (which, as shown in the work, reliably correlates with their biochemical activity

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure &lt; 100 mmHg (n = 1127), estimated glomerular filtration rate &lt; 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

The Emergence of SARS-CoV-2 within the Dog Population in Croatia: Host Factors and Clinical Outcome

Over a year into the COVID-19 pandemic, there is growing evidence that SARS-CoV-2 infections among dogs are more common than previously thought. In this study, the prevalence of SARS-CoV-2 antibodies was investigated in two dog populations. The first group was comprised of 1069 dogs admitted to the Veterinary Teaching Hospital for any given reason. The second group included dogs that shared households with confirmed COVID-19 cases in humans. This study group numbered 78 dogs. In COVID-19 infected households, 43.9% tested ELISA positive, and neutralising antibodies were detected in 25.64% of dogs. Those data are comparable with the secondary attack rate in the human population. With 14.69% of dogs in the general population testing ELISA positive, there was a surge of SARS-CoV-2 infections within the dog population amid the second wave of the pandemic. Noticeably seroprevalence of SARS-CoV-2 in the dog and the human population did not differ at the end of the study period. Male sex, breed and age were identified as significant risk factors. This study gives strong evidence that while acute dog infections are mostly asymptomatic, they can pose a significant risk to dog health. Due to the retrospective nature of this study, samples for viral isolation and PCR were unavailable. Still, seropositive dogs had a 1.97 times greater risk for developing central nervous symptoms