Verification of Fatigue Damage and Prognosis Related to Degradation of Polymer-Ceramic

Statistically, road accidents involving pedestrians occur in the autumn and winter months, when outdoor temperatures reach −30 °C. The research presented in this paper investigates the impact of a pedestrian’s head on laminated windscreen, taking into account the effects of external temperature, heating of the windscreen from the inside, and fatigue of the glass. The automotive laminated windscreen under study is made from two layers of glass and a Polyvinyl Butyral (PVB) resin bonding them together. PVB significantly changes its properties with temperature. The Finite Element Method (FEM) simulations of a pedestrian’s head hitting the windscreen of an Opel Astra II at <−30 °C, +20 °C> were performed. The obtained Head Injury Criterion (HIC) results revealed an almost twofold decrease in safety between +20 °C and −20 °C. The same test was then performed taking into account the heating of the windscreen from the inside and the fatigue of the glass layers. Surprisingly, the highest HIC value of all the cases studied was obtained at −30 °C and heating the windscreen. The nature of safety changes with temperature variation is different for the cases of heating, non-heating, and fatigue of glass layers. Glass fatigue increases pedestrian safety throughout the temperature range analysed.

Importance of immunodiagnostics in dynamic observation of tuberculosis treatment in children

The use of recombinant tuberculosis allergen (ATR) expands the possibilities of detecting tuberculosis. Nevertheless, the issue of the predictive value of the ATR test for assessing the result of tuberculosis therapy remains insufficiently studied.Purpose. Тo clarify the information content of changes in the results of a test with a recombinant tuberculosis allergen against the background of chemotherapy for tuberculosis in children.Materials and methods. We used the data of patients with active tuberculosis aged 0 to 14 years who were hospitalized. The main group in the study (1st) included 280 children with a pronounced reaction to ATR, the comparison group (2nd) consisted of 42 children with a moderate, mild and doubtful reaction to ATP at the time of tuberculosis detection.Results. After 6 months from the beginning of the intensive phase of tuberculosis treatment, a hyperergic reaction to the administration of ATR was diagnosed in 74 (38.7%) children of the 1st group and 4 (16.7%) children of the 2nd group (p = 0.025). A twofold decrease in the sample size was observed in children of the 1st group (121 children – 63.4%) than the 2nd (7 children – 29.2%) (χ2 = 8.97, p = 0.003; OR = 4.198; 95% CI 1.66–10.62). The increase in the sample is 2.9 times higher in children of the 2nd group (44 children – 23%) than in children of the 1st (χ2 = 20.17, p = 0.000).Conclusions. The extinction of sensitivity to the ATR test after specific therapy is 2 times higher in children who initially had a pronounced reaction. In the same group, a hyperergic reaction to the sample often persists or occurs after the intensive phase of anti-tuberculosis therapy.

Modification of Canola Oil Physicochemical Properties by Hexane and Ethanol with Regards of Its Application in Diesel Engine

A mixture of canola oil (Co), n-hexane (Hex), and ethyl alcohol (Et) was proposed as a new energy material for powering diesel engines. For this purpose, surface tension, density, and viscosity measurements, as well as engine tests, were performed for 88%Co10%Hex2%Et and 83%Co15%Hex2%Et mixtures at 20 °C. The adsorption and volumetric properties of these mixtures were compared to those of individual mixture components, as well as diesel fuel (Df) and oleic, linoleic, α-linolenic, palmitic, and stearic acids. It was revealed that the values of surface tension, viscosity, and density of Co were higher than those of the Co components. The addition of 10% Hex and 2% Et to Co caused a more than twofold decrease in its viscosity, while the addition of 15% Hex and 2% Et caused a more than fourfold reduction of Co viscosity. In addition, a mixture of Co with 2% Et and 10% Hex had a density similar to that of Df. In turn, theoretical calculations showed that the addition of n-hexane and ethanol to canola oil only slightly changed its heat of combustion. Engine tests were carried out at fixed engine rotational speeds, with a direct gearbox ratio (4th gear). The quick-changing parameters of the combustion process were registered using an AVL Indimicro system. In these tests it was found that the addition of Et to the mixture of Co and Hex did not significantly shorten the auto-ignition delay, but the kinetic phase during combustion disappeared, which had an impact on the combustion start angle.

ABOUT THE PROBLEM OF ACCOUNTS IN THE ECONOMY OF RUSSIA

In modern conditions, receivables have become an integral part of the economy of domestic enterprises, which is associated with economic instability, variations in their financial stability and often negatively affects the solvency. The growth of accounts receivable adversely affects the financial turnover of creditor enterprises, for debtors the impossibility of quick and timely fulfillment of financial obligations leads to an increase in accounts payable, thereby reducing their financial stability and increasing the likelihood of bankruptcy, which makes the problem of formation of accounts receivable a topical research area. During the study, an assessment of the state of receivables in the Russian economy was carried out, the main trends and their causes were identified. It was found that the volume of accounts receivable in the Russian economy today, despite an almost twofold decrease in 5 years - from 11.4 trillion. rub. up to 6.2 trillion rubles, as before, is quite impressive, which is associated with economic instability, accompanied by periods of greater recession and crisis phenomena. This is confirmed by the results of the study, which emphasize that today in the economy about 20% of the financial assets of enterprises are in the form of accounts receivable. Effective management of accounts receivable in difficult economic conditions is becoming increasingly important, since it is aimed at improving the overall performance of domestic enterprises and the economy.

Upgrading of Heavy Oil in a Hydrothermal System in the Presence of Modified Aluminosilicates

The results of upgrading heavy crude oil with a density of 0.9857 g/cm3 and a sulfur content of 3.6% wt. are presented. In an environment of superheated steam in the temperature range 355-375°C and pressures up to 14 MPa in the presence of iron-modified natural aluminosilicates. The use of modified aluminosilicates containing oxides of iron, aluminum and silicon in the process of upgrading heavy oil led to a twofold decrease in the content of resinous-asphaltene components in it. In addition, the upgrading process led to an increase in the content in light fractions, boiling up to a temperature of 300°C, of the converted oil of branched alkanes with a high octane number, as well as to a decrease in oil viscosity by 60%.

Changes in air tourism to Tunisia in 2009–2018

Background: T he subject of this study is an analysis of the changes of tourist air traffic in Tunisia between 2009 and 2018. During this time, Tunisia saw political changes and worldwide-reported coverage of terrorist attacks on tourists (2014–2015). The aim of this study was to attempt to determine the extent to which the Tunisian Revolution and terrorist attacks have had a negative impact on the decline in the tourist traffic, and to assess the rate of return of the tourist traffic and income in this sector to the levels from before the Revolution. Material and methods: The main source of statistical data for Tunisian airports are documents List of the busiest airports in Africa and Trafic Mondial / World Traffic, and data collected from individual airports for the relevant years. The main problem in the analysis and correlation was the access to reliable data on the volume of tourist traffic, and in the case of some airports, data presenting the volume of passenger traffic. Data from the Statistical Office of Tunisia were used to identify and analyse changes in revenues. Results: Data for 2009–2018 clearly show a decrease in the number of all passengers arriving in Tunisia by air travel. Conclusions: R esearch suggests that the decline in the number of tourists as a result of political changes and terrorist attacks has been characterised by different dynamics. Political events have a lower impact on the decrease in the number of tourists and have an effect over a longer period. It seems that after a period of a twofold decrease in the number of tourists – firstly, because of the revolution, and secondly, because of attacks after 2016, Tunisia has entered a period of prosperity in tourism, as evidenced by data for 2017–2018. However, after the record-breaking year 2019, the first quarter of 2020 began under the sign of the Coronavirus pandemic, and tourism around the world is facing a period of stagnation.

The Role of Serum Calprotectin as a New Marker in Abdominal Aortic Aneurysms – A Preliminary Report

Background: Abdominal aortic aneurysm (AAA) remains a surgical challenge. There are many recognizable markers associated with the formation of AAA. Previous experiments carried out on animal models have shown a correlation between serum calprotectin and the occurrence of AAA. Objective: This study aimed to evaluate the level of calprotectin as a potential diagnostic biomarker in patients with diagnosed AAA. Method: The study group consisted of 75 patients aged 35–75 years who were assigned to two groups: a control group (n=43) of healthy subjects without AAA and a study group (n=32) of patients with a diagnosed AAA. The first calprotectin test was performed upon patient admission to the hospital, and the second control test was performed after three months. The concentration of calprotectin in plasma was determined using the immunoenzymatic method (ELISA) with the commercially available Assaypro Kit (AssayMax™ Human Calprotectin ELISA Kit), as well as the sandwich method with polyclonal antibodies to human calprotectin and peroxidase enzyme. Results & Discussion: Serum calprotectin levels in AAA patients were three times higher than in healthy subjects (p<0.05). A statistically significant a twofold decrease in calprotectin concentration was observed after AAA surgery in comparison with the control group (p<0.05). Conclusion: Calprotectin levels can be an important marker in the detection of AAA. In conclusion, AAA patients showed a threefold increase in serum calprotectin level and a twofold decrease in this marker after AAA surgery.

Rsp Activates Expression of the Cnt System in Staphylococcus aureus

Background: The Cnt system is crucial for the optimal import of essential metals in metal-limiting conditions and contributes to virulence in S. aureus. In a screen for regulators of efflux pumps in a phage-based ultra-high-density transposon library, we identified Rsp as a candidate regulator of the cntE gene. Results: A twofold decrease in expression of all genes of the cnt operon was observed by RT-qPCR in the rsp mutant compared to the parental strain, indicating that Rsp acts as an activator of the cnt operon. To determine whether the Rsp activation depends on iron, we compared mutant and parent cnt expression under varying metal conditions. A 2-fold reduction in cnt gene expression was detected in the rsp mutant in TSB, and a slightly smaller decrease (1.9, 1.7, and 1.5-fold changes for cntK, cmtA, and cntE respectively) was observed after addition of dipyridyl. The greatest decrease was seen with addition of FeSO4 (4.1, 5.3 and 6.3-fold changes for cntK, cmtA and cntE respectively). These findings suggest that Rsp activates the cnt operon in low and high iron conditions. To study the relationship between Rsp and the cnt repressors Fur and Zur, we created single and double mutants. Both fur and zur single mutants had significant increases in cnt gene expression compared to the parental strain, as did the fur rsp double mutant. The zur rsp double mutant also had a significant increase in cntK expression and a trend in increases in cntA and cntE expression just below statistical significance. Thus, the ability of Fur and Zur to repress cnt gene expression are not eliminated by the presence of Rsp. However, there were significantly smaller increases in cnt gene expression in the double mutants compared to single mutants, suggesting that Rsp activation can still occur in the absence of these repressors. To determine if Rsp directly modulates expression of cnt genes, incubation of purified Rsp caused a DNA-specific band shift for the cntK and cntA promoters. Conclusions: Rsp activation may act to maintain basal cellular levels of staphylopine to scavenge free metals when needed, in addition to metal dependent regulation by Fur and Zur.

How a raindrop gets shattered on biological surfaces

Many biological surfaces of animals and plants (e.g., bird feathers, insect wings, plant leaves, etc.) are superhydrophobic with rough surfaces at different length scales. Previous studies have focused on a simple drop-bouncing behavior on biological surfaces with low-speed impacts. However, we observed that an impacting drop at high speeds exhibits more complicated dynamics with unexpected shock-like patterns: Hundreds of shock-like waves are formed on the spreading drop, and the drop is then abruptly fragmented along with multiple nucleating holes. Such drop dynamics result in the rapid retraction of the spreading drop and thereby a more than twofold decrease in contact time. Our results may shed light on potential biological advantages of hypothermia risk reduction for endothermic animals and spore spreading enhancement for fungi via wave-induced drop fragmentation.

Structure of Patients with Hepatocellular Cancer (Data Analysis from Two Specialised Centres)

Aim. To identify trends in the structure of patients with liver diseases, in particular hepatocellular cancer (HCC), by analysing the experience of two specialised medical centres.Materials and methods. A retrospective analysis of the medical records of hepatological patients who sought medical treatment at to the V.Kh. Vasilenko Clinic of Propaedeutics of Internal Diseases, Gastroenterology and Hepatology of the Sechenov University in 2013, 2014 and 2017 (total 2459 patients) was carried out. The number of patients with chronic viral hepatitis (CVH) was 651, with non-alcoholic fatty liver disease (NAFLD) — 590, with alcoholic liver disease (ALD) — 66, with autoimmune liver diseases — 416, with liver cirrhosis (LC) of any etiology 407, other liver diseases — 329. A retrospective analysis of the medical records of patients with HCC who were examined and treated at the N.V. Sklifosovsky Research Institute for Emergency Medicine in the period from 2008 to 2017 (n = 86) was carried out.Results. The ratio of patients with chronic hepatitis C and B in 2013–2017 significantly changed. An almost twofold decrease in the number of patients with chronic hepatitis C (210 patients in 2013 and 141 patients in 2017) and an increase in the number of patients with chronic hepatitis B (20 patients in 2013 and 45 patients in 2017) was observed. An almost twofold increase in the total number of NAFLD patients was detected (163 patients in 2013 and 276 patients in 2017). The number of ALD patients increased from 12 patients in 2013 to 31 patients in 2017. The proportion of patients with autoimmune liver diseases in the overall structure of patients who applied to the department was 20 % in 2013, 13.6 % in 2014 and 10.8 % in 2017. An almost twofold decrease in the number of patients with alcoholic LC and LC associated with HBV was observed (73 patients and 17 patients in 2013 and 38 patients and 6 patients in 2017, respectively) as well as a noticeable increase in the number of patients with alcoholic LC and LC associated with HCV (6 patients and 51 patients in 2013 and 26 patients and 75 patients in 2017, respectively). In the analysis of HCC patients, the ratio of men to women was 3:1 (64 men and 22 women), the median age was 54.5 years (IQR 48–59). The median time from the establishment of chronic liver disease to the detection of HCC was 7.5 years (IQR 3–14.5). In 86 % of cases, the HCC development was preceded by cirrhosis (Child-Pugh A: n = 24; Child-Pugh B: n = 30; Child-Pugh C: n = 20), in 14 % — by chronic hepatitis. Viral liver lesions were the leading cause of HCC in 79 % (n = 68), ALD in 4 % (n = 3), NAFLD in 1 % (n = 1), AIH in 1 % (n = 1). In 10 % (n = 9), a combined liver lesion was observed, in 5 % (n = 4), no previous liver disease was known. The highest five-year survival rate (100 %) was found in the group of patients who received antiviral therapy (AVT) before and after liver transplantation.Conclusions. NAFLD, ALD, and chronic hepatitis B patients began to seek medical help more frequently. An increase in the number of patients with autoimmune LC and LC associated with chronic hepatitis C virus (HCV) infection was observed. The conducted analysis of trends in the structure of HCC patients showed that chronic HCV and HBV infection is the main prerequisite for the development of cancer. Liver transplantation is the most effective treatment for HCC. AVT before and after liver transplantation allows a statistically significant increase in the five-year posttransplant survival of HCC patients with chronic hepatitis C to be achieved.