Search

We investigate the effects of the use of different sources of investment leverage, i.e. securities with embedded leverage and traditional margin accounts, on the portfolio performance of retail investors, recognizing that these effects may be conditional on investor attention. We find that investors who trade on margin underperform those who do not have margin accounts, but we also find that investors who trade securities with embedded leverage show an even poorer performance than investors who trade on margin. The negative effect of leverage usage decreases with greater investor attention, measured by portfolio monitoring frequency. These results suggest that more attentive investors gain more from the use of investment leverage.

In this work, we experimentally investigate the effects of electric bias on the degradation of few-layer MoS2 back-gated field-effect transistors in ambient air. The devices were fabricated using mechanically exfoliated MoS2 flakes, which were transferred to a Si/SiO2 substrate by a PDMS-based transfer. We report an accelerated electric bias-induced degradation of the devices under investigation and used optical and scanning electron microscopy (SEM) to monitor changes of the morphology of the MoS2 channel. In particular, we found a linear dependency of the degradation on the electric field between the Ti/Au source and drain contacts. In addition, we identify four regions in which morphological changes occur, of which the edges of the MoS2 channel are most affected.

Estrogens play an extremely important role in regulating the proliferation of ovarian cancer. The estrogen receptor alpha (ERα) stimulates cell growth, whereas ERβ can be attributed to tumor suppressors. The study aims to assess the relationship between the expression of estrogen receptors in tumors and the efficacy of front-line platinum plus taxane chemotherapy in ovarian cancer patients. ERα and ERβ tumor expression was evaluated quantitatively by flow cytometry in a narrowly defined group (31 patients): stage III high-grade serous ovarian carcinoma (HGSOC), suboptimal surgical cytoreduction, front-line platinum plus taxane chemotherapy (front-line, six cycles). The median of progression-free survival (PFS) was 2 times greater (18 vs 8 months, p = 0.04) and the recurrence risk (HR) was 2.2 times (95 % CI: 1.1–6.2, p = 0.04) lower in the group with high (in more than 40% of the cells) vs low level of ERβ tumor expression. The statistically significant difference between PFS in the groups with high vs low tumor ERα expression was not revealed. A high level of ERβ and not ERα expression can predict the efficacy of front-line platinum plus taxane chemotherapy in stage III HGSOC patients. The status of estrogen receptor beta can be considered as one of the possible predictors for evaluating the effectiveness of ovarian cancer therapy.

Crystallographic defects can now be routinely imaged at atomic resolution with aberration-corrected scanning transmission electron microscopy (STEM) at high speed, with the potential for vast volumes of data to be acquired in relatively short times or through autonomous experiments that can continue over very long periods. Automatic detection and classification of defects in the STEM images are needed in order to handle the data in an efficient way. However, like many other tasks related to object detection and identification in artificial intelligence, it is challenging to detect and identify defects from STEM images. Furthermore, it is difficult to deal with crystal structures that have many atoms and low symmetries. Previous methods used for defect detection and classification were based on supervised learning, which requires human-labeled data. In this work, we develop an approach for defect detection with unsupervised machine learning based on a one-class support vector machine (OCSVM). We introduce two schemes of image segmentation and data preprocessing, both of which involve taking the Patterson function of each segment as inputs. We demonstrate that this method can be applied to various defects, such as point and line defects in 2D materials and twin boundaries in 3D nanocrystals.

Research on additives is important for many oil companies today. The rapidly growing market for lubricants has led to efforts to improve such materials through the development of new compositions. In the past decade, a strategic goal of the Russian oil refining industry has been to develop domestically-produced additives, compositions, and additive packages. In this article, trends are discussed on the development of promising products derived from a compound used in the synthesis of multifunctional additives.

The paper summarized the data about vascular plant species of Poltava town territorial commune formed in 2020 during decentralization reform within Poltava district of Poltava region. Based on own field research in 2006–2021 authors found on this territory 996 vascular plant species from 105 families. They include 911 species from 432 genera and 101 families which are resident taxa and belong to a stable components of a plant cover on this territory; they grow a long time here and have a regular self-healing ability. The annotated list of resident plant species with main their synonymic Latin names is indicated. 85 species from 77 genera and 32 families have also been found on the research territory but they are not to be able to accept as a stable component of a plant cover since they are locally distributed, occasionally escaped from cultivation or alien and are not naturalized here.These species were included in the additional list indicated in this paper too; they need a monitoring research for their status and further distribution on this territory. It was established that the territory of Poltava town commune has a great species diversity of vascular plants: 63,3% of resident taxa which were found in the Left Bank Forest-Steppe of Ukraine and 73,9% of resident taxa found in Poltava region have been discovered by authors. The features of Poltava town commune are high participation (61 species or 6,1%) rare vascular plant species – 14 from «The Red Data Book of Ukraine» and 47 regionally rare plant species within Poltava administrative region, and rather low degree of preservation area (0,3%). So the priority task for the development of Poltava town territorial commune in a direction of a biodiversity conservation is to be creation of new preservation territories on areas with the high concentration of rare vascular plant species., Стаття узагальнює дані про видовий склад судинних рослин Полтавської міської територіальної громади, яка була утворена у 2020 році унаслідок реформи децентралізації у межах Полтавського району Полтавської області. На цій території авторами під час власних польових досліджень 2006–2021 рр. було зафіксовано 996 видів судинних рослин зі 105 родин. Серед них 911 видів, які входять до складу 432 родів і 101 родини, належать до резидентних таксонів, тобто є стабільними компонентами рослинного покриву цієї території, існують на ній тривалий час та регулярно самовідновлюються. Наведено перелік цих видів з їх найголовнішими синонімічними латинськими назвами. Також було виявлено 85 видів з 77 родів і 32 родин, які поки що не можуть вважатися стабільними компонентами рослинного покриву дослідженої території, оскільки вони є малочисельними, періодично дичавіють з культури чи випадково заносяться і при цьому не натуралізуються. Такі види наведені окремим додатковим переліком, вони потребують моніторингу за їхнім подальшим поширенням у регіоні. Встановлено, що територія Полтавської міської громади відзначається значною видовою різноманітністю судинних рослин, на ній зафіксовано 63,3% резидентних таксонів, поширених на території Лівобережного Лісостепу України, та 73,9% резидентних таксонів, які трапляються у Полтавській області. Особливістю дослідженого регіону є висока частка (61 вид або 6,1%) рідкісних видів судинних рослин – 14 видів з «Червоної книги України» і 47 регіонально рідкісних, а також дуже низький відсоток заповідності (близько 0,3% площі громади). Тому пріоритетним завданням розвитку Полтавської міської територіальної громади у плані збереження біорізноманітності має стати розроблення наукових обґрунтувань для створення нових об’єктів природно-заповідного фонду у місцях найбільшої концентрації рідкісних видів судинних рослин.

The purpose of the paper. In order to solve the problems of increasing the efficiency of machining operations of small diameter holes by milling, the optimal range of cutting modes and helix pitch for the machining strategy with helical interpolation is established. The reduction of labor intensity and costs of hole machining when treating holes in alloyed corrosion-resistant steels is experimentally confirmed. Research methods. In this paper, the issues of machining blind holes by helical interpolation milling with end cylindrical carbide cutters of relatively small dimensions in parts made of 12X18N10T alloy are considered. The features of this machining are availability of significant axial and radial components of the cutting forces with relatively low tool strength. This leads to the fact that a key factor of the tool failure is its mechanical failure, the cause of which is an increase in cutting forces due to the edge of the cutter being chipped. Research results and novelty. It has been experimentally proved that the most rational machining parameters to ensure the specified accuracy and surface quality of the machined holes when using a strategy of helical interpolation milling will be the choice of the helix pitch p = 0.2 mm, the feed range F = 0.075-0.11 mm /tooth, which corresponds to the minute feeds of the milling center 450-675 mm/min. Conclusions. The optimal range of cutting modes is found in the feed range from 450 to 675 mm/min, with a helical interpolation pitch of 0.2 mm. The accuracy and roughness of the holes obtained by milling with end mills with a diameter of 3 mm for steel 12X18N10T is evaluated.

Background. Decline of oil and gas traditional reserves pushes companies to explore and involve in production complex reservoirs which results in exploration risks increase. That is why an exploration research has to be integrational and its’ main result has to be determination and decreasing uncertainties. Aim. The aim of this research is the planning of further exploration program within the studied territory, based on the main uncertainties and trends in geological development. Materials and methods. Several types of research methods were applied, including field observation, laboratory analysis and geological desktop studies. The results of petroleum systems modeling is the basis for source rocks maturity prediction, the main stages of hydrocarbons generation — migration and critical moment estimation. It also provided the analysis of migration distance (limits) and geological risks related to it, petroleum saturation prediction for the main plays. Great emphasis was also placed on the search and processing of additional archival data, which made it possible to significantly detail the structural-tectonic framework of the studied area. Results. Consistent progression in field observation, laboratory analysis and geological desktop studies allowed to narrow the range of uncertainties, clarify the chance of geological success (gCOS), plan the further exploration program, and highlight higher-priority license blocks. As a result, more than 60 additional prospects were identified, for each of them both the probabilistic estimation of oil and gas resources and chance of geological success evaluation were made. Moreover, the further exploration program was approved. Conclusions. Therefore, the study allowed to analyse main uncertainties and correct further exploration program on the basis of integrated analysis of geological development history and geological structure of the studied area.

Three groups of charged particles are recorded at the impact of the laser radiation pulse with a metal target in a rarefied gas medium. The optical range laser radiation intensity is ~109 W/cm2. A possibility of using a Langmuir probe for diagnosing plasma processes with nanosecond resolution is demonstrated.

A lack of personalized approaches in non-medication pain management has prevented these alternative forms of treatment from achieving the desired efficacy. One hundred and ten female patients with fibromyalgia syndrome (FMS) and 60 healthy women without chronic pain were assessed for severity of chronic or retrospective occasional pain, respectively, along with alexithymia, depression, anxiety, coping strategies, and personality traits. All analyses were conducted following a ‘resource matching’ hypothesis predicting that to be effective, a behavioral coping mechanism diverting or producing cognitive resources should correspond to particular mechanisms regulating pain severity in the patient. Moderated mediation analysis found that extraverts could effectively cope with chronic pain and avoid the use of medications for pain and mood management by lowering depressive symptoms through the use of distraction mechanism as a habitual (‘out-of-touch-with-reality’) behavior. However, introverts could effectively cope with chronic pain and avoid the use of medications by lowering catastrophizing through the use of distraction mechanism as a situational (‘in-touch-with-reality’) behavior. Thus, personalized behavior management techniques applied according to a mechanism of capturing or diverting the main individual ‘resource’ of the pain experience from its ‘feeding’ to supporting another activity may increase efficacy in the reduction of pain severity along with decreasing the need for pain relief and mood-stabilizing medications.

Medicinal liver damage is an important problem not only in the framework of hepatology and gastroenterology, but also for internal medicine in general, which is due to the difficulties of correct and timely diagnosis of this pathology. In the first part of the review, the main mechanisms of liver tissue damage and clinical and formological manifestations of drug-induced liver damage are considered. The pandemic of the new coronavirus infection (COVID-19), spread by the SARS-CoV-2 virus, has become a challenge to health systems around the world. The global clinical experience gained over the past year in the management of patients with a new coronavirus infection makes it possible to highlight a number of relevant clinical aspects, one of which is drug-induced liver damage associated with the treatment of COVID-19. In the second part of the review, the possible mechanisms of influence of COVID-19 on the hepatobiliary system are considered, which include viral cytotoxicity, a secondary effect of immune dysregu-lation;hypoxia as a result of respiratory failure and subsequent ischemic liver damage;reactivation of already existing liver pathology and drug damage to the liver. It has been established that a large number of drugs used to treat COVID-19-antiviral agents, antibacterials, non-steroidal anti-inflammatory drugs, steroids and others-have hepatoxic effects and can cause liver damage. In the context of the COVID-19 pandemic, for patients with a new coronavirus infection and drug-induced liver damage, a rational, pathogenetically justified choice of a hepatoprotective drug is of particular importance. In the final part of the review, the possibilities of the polyionic succinate-methionine complex in the treatment of drug-induced liver damage are considered and a clinical example of the drug application in a patient with drug-induced liver damage during treatment with COVID-19 is given. © 2021, Remedium Group Ltd. All rights reserved.

A dentist needs special knowledge in odontology and odontoglyphics, which allows visualizing the space and relief of the tooth surface, as well as conducting an in-depth analysis of the individual morphometric characteristics of the tooth. Expansion of knowledge about the variability of the occlusal relief will allow achieving balanced occlusal-articulation relationships of the dentition and preserving the physiological state of the dentition. The article presents the results of odontoscopic and morphometric studies of vertical, transverse parameters of the upper large molars in patients with various physiological types of occlusion. The subject of the study was the segments of the upper molars obtained from plaster models of the jaws of 92 people with physiological occlusion, a full set of permanent teeth and various types of dental system (patients in group 1 – normodontism, patients in group 2 – macrodontism, patients in group 3 – microdontism). For morphometry in the transverse direction, the vestibular-lingual size of the crown and neck of the tooth, as well as the intertubercular distance, were used. To measure the vertical parameters, the height of the mesial (protocone, paracone) and distal (metacone, hypocone) odontomeres and tubercle of the occlusal surface was determined. The results of the study showed that in people with physiological occlusion and macrodontism of permanent teeth, vertical, transverse parameters exceed those of people with normodont and microdont types of the dental system. It is advisable to use the obtained odontometric features at the stages of diagnosing occlusal relationships and identifying various forms of pathological, physiological abrasion with varying degrees of loss of occlusal surfaces.

The hypothesis of discharge initiation in vacuum gap by optical range radiation based on previously obtained experimental data. During the laser pulse interaction with electrode erosion products the glow discharge has ignited. In result of ioniza-tion-overheating instability the discharge has had current channel contraction and has transferred to arc. The dependences of material of target thermo dynamical parameters on the minimal and threshold laser pulse energy have demonstrated. The threshold laser pulse energy – the energy which enough to effective impact on the laser plasma.

The anomalous vertical distribution of organic aerosol recorded on September 14, 2018, is analyzed on the basis of aircraft sounding data. It is anomalous in that, in contrast to the long-term average profile, the maximal concentration in the boundary layer during this flight was more than an order of magnitude higher than the previously measured concentrations. The contribution of aerosols of different origins to the total concentration in different tropospheric layers is estimated. The analysis of possible sources of aerosol precursors revealed quite a wide sector, on the territory of which there are boreal forests, which are sources of biogenic compounds, and objects of industrial infrastructure, which are sources of anthropogenic emissions.

1,500 respondents took part in an Internet survey conducted in autumn 2020 in the Russian Federation. The survey was a part of the Radon Cross-Cultural Multilingual Public Opinion Survey (STEAM project) in the framework of the IAEA technical cooperation project RER9153. The survey was representative for the population of the country as per sex, age, and a region of residence. Random sampling error didn’t exceed 2.5 % for 95 % confidence interval. All respondents were given some information on radon that was as similar as possible in questionnaires published in languages spoken in all 22 coun- tries that took part in the STEAM project; it was done in order to provide an opportunity to make further cross-country com- parison of the survey results. The objective of the survey was to investigate what attitudes people had towards their health and towards radon as a possible health risk factor. The survey revealed that in the Russian Federation people were rather poorly aware about radon. Only 31.7 % re- spondents stated that they were to a greater or lesser extent informed about radon. The level of knowledge about radon as a health risk factor was at a comparable level. For the majority of respondents, information about radon received from Ro- spotrebnadzor and its subordinate research institute formed the perception of radon as a risk factor that requires actions to mitigate its impact on health. Medical specialists turned out to be the most trustworthy source of information about health risks, first of all, family doctors and physicians in polyclinics; people also trusted medical prevention centers, Rospotrebnad- zor, regional and local public health care authorities. Results of the presented survey that was the first social survey focusing on the radon problem and conducted through- out the country can be used as a basis for planning communication strategies within the framework of both national and regional radon programs.

A method has been developed for identifying the occurrence of incipient defects in the new ship machinery units that have not previously passed vibrodiagnostic testing, in the absence of statistical data on changes in the vibroacoustic parameters and diagnostic features under the action of characteristic malfunctions. A method for identifying faulty units with incipient defects under the action of unknown malfunctions has been implemented. An algorithm has been developed for constructing the boundaries of reference domains by integrating conditional multidimensional probability densities of feature spaces, which characterize the distribution of incipient defects for the operational state of the machinery. A rule is proposed for identifying the occurrence of incipient defects in individual machinery units in the case of multidimensional features passing beyond the boundaries of the reference domains. A rule is proposed for identifying the occurrence of incipient defects in the machinery units constructed based on a nonparametric goodness-of-fit criterion for assessing the coincidence of conditional distribution functions of multidimensional features characterizing these defects. Experimental verification of the developed method was carried out during in situ vibroacoustic tests of ship machinery.

The structure of the hull of the project 1288 trawler in a region of fore hold was improved to ensure fatigue strength of assemblies of the intersection of main frames with the second bottom. To this end, a study of the fatigue strength of these assemblies was carried out for the original side structure and two versions of its modernization. Values of internal forces at the points of appearance of fatigue cracks in the compartment have been determined for three design versions of the side. It was found that the greatest forces act in the middle of the fore half of the compartment. Calculations of parameters of the long-term distribution of magnitudes of ranges of total equivalent operating stresses according to the Weibull law in the points of occurrence of fatigue cracks for different design versions of the side grillage have been performed. These parameters were determined for the middle of the fore hold of the vessel and for the areas in which maximum values of bending moment ranges are in effect with and without corrosive wear. Values of total fatigue damage and durability of the studied assemblies were determined. Calculations were carried out by nominal stress method, hot spot stress method, and experimental and theoretical method. It was shown that in order to ensure fatigue strength of the assembly under consideration, it is necessary to extend the intermediate frames of the original version of the side structure to the level of the second bottom fixing them to the deck. It is also necessary to attach a cargo platform to the side thus reducing the frame span. As a result, the level of fatigue damage over 25 years of operation will decrease by about 3.5 times. As it was found, approximate consideration of the slamming effect does not significantly increase the amount of fatigue damage to the assembly. The results of the development of recommendations for modernization of the side structure can be implemented both on ships of the 1288 project and on other ships with a transverse side framing system.

The article is focused on the analysis of problems of development and forecasting of small enterprises in the Kyrgyz Republic in the field of education. The methodology of forecasting the gross income of small and medium-sized enterprises in the field of education is offered. An approach related to the use of the least-squares method as a forecasting tool is proposed. In this regard, the conditions of formation and functioning of the market of paid educational services in the Kyrgyz Republic, which are closely related to the definition of demand, supply and market prices for educational services are characterized. The results allow us to accurately determine the interval in which we can predict with maximum probability the future volume of the gross income of small and medium-sized enterprises in education from 2019 to 2023, which will slowly decline. It was also found that small enterprises in education have certain advantages over large educational institutions. They are more dynamic, faster and more efficient in responding to changes in the domestic market, both in times of growth and in times of crisis. The findings of the research reflect the actual situation. They are adequate and can be useful in assessing the effectiveness of business creation in the Kyrgyz Republic in the provision of educational services.

The problems of monitoring the state of flowing media with a simultaneous change in temperature and flow rate of the medium by more than two orders of magnitude are considered. A design of a flow-through refractometer is proposed for monitoring the state of transparent media in laminar and turbulent flow regimes, as well as at high flow rates and changes in the temperature of the medium by more than 200°C. The developed flow-through refractometer implements a method for measuring the refractive index, based on the principle of parallelism of two beams: the incident and transmitted through a pipeline with refraction at the boundaries of several media. The piping in the form of a cylindrical Plexiglas insert is part of the refractometer design. The design of the optical part of the refractometer with a vertical section of the pipeline eliminates the influence on the measurement of the refractive index of errors caused by multiple reflections of laser radiation from optical elements, the formation of voids or vortex flows in the pipeline. For the proposed refractometer there are no restrictions on the value of the measured refractive index of the flowing liquid, in contrast to the previously used industrial flow-through refractometers, the principle of operation of which is based on the phenomenon of total internal reflection of laser radiation at the interface of two media. The results of experimental studies of various media with the proposed refractometer are presented.

Introduction. Currently, a large number of techniques are used in the treatment of patients with ureteral stones: extracorporeal shock-wave lithotripsy (ESWL), retrograde ureterolithotripsy (RULT), laparoscopic and retro-peritoneoscopic ureterolithotomy.Purpose of the study. To evaluate the possibilities and effectiveness of percutaneous antegrade ureterolithotripsy in the treatment of patients with proximal ureteral stones in comparison with transurethral contact ureterolithotripsy.Materials and methods. Twenty-eight patients with urolithiasis were treated, who underwent percutaneous antegrade ureterolithotripsy (PAULT) and 27 patients of the control group, who underwent RULT. All patients included in the study underwent a standard preoperative examination: complete blood count and urine analysis, bacteriological urine culture, biochemical tests, and X-ray research methods. Plain urography, renal ultrasound, computed tomography were used as imaging methods. The OLYMPUS URF-V3 8.4 Ch (Olympus Europa SE & Co. KG., Germany) video uretero-renoscope was used for PAULT in patients of the main group; lithotripsy was performed using thulium laser. The results of the study were subjected to statistical processing in order to determine the statistical significance of the differences between the data obtained. Quantitative variables were described using the arithmetic mean (M) and standard deviation (5). Qualitative variables were estimated by absolute and relative frequencies (percentages). The data were considered reliable at p values < 0.05.Results. The average time of surgical intervention in patients of the main group from the moment of placement of the ureteral catheter was 47 ± 12 min, with access without preliminary renal catheterization: 28 ± 4 min. Average time of surgical intervention in patients of the control group: 42.0 ± 10.7 minutes. The presented data indicate a significant (p < 0.05) greater cases' number of complete stone removal among patients of the main group compared with patients in the control group (74.0%).Conclusion. PAULT is preferred among choice treatment methods for patients with proximal ureteral large stones, for whom RULT and ESWL cannot be performed with a high level of “stone-free” rate and a minimum number of complications.

The article summarizes data about the distribution of Corynephoruscanescens(L.) P.Beauv.in the Left Bank Forest-Steppe of Ukraine. This species which is native for Europe and North Africa was firstly found on the research territory. Currently nine localities of this vascular plant species are known within Kyiv (seven locations) and Poltava (two locations) administrative regions. Based on the analysis of geobotanical relevés made by authors on psammophytic vegetation plots with the participation of Corynephoruscanescensit was found that studied sand areas within Kyiv region belong to the associationCorniculario aculeatae-Corynephoretum canescentis Steffen1931 from the classKoelerioglaucae-CorynephoreteacanescentisKlikainKlika& Novak1941 (allianceCorynephorioncanescentisKlika1931, orderCorynephoretaliacanescentisKlika1934); they have clear two-layered structure with the substantive complicity of moss and lichen species. On the other hand, similarpsammophytic communities within Poltava region have the simplified one-layered composition with the tenuous herb cover and the absence of moss and lichen layers; they are treated by authors as a separate community –comm. CorynephoruscanescenswithintheclassKoelerioglaucae-Corynephoreteacanescentis. Based on these ecological data,Corynephoruscanescensis considered as a species with dissimilar status in different parts of the research territory. Found localities of this species within Poltava region are to be treated as alien and associated with human activity,but in the southern part of Kyiv region,the autochthonous (or atleast simultaneously mixed indigenous and antropogenic) dispersal of its diaspors by anemochory is quite reliable. The phytosociological tables of geobotanical relevés made by authors in Kyiv and Poltava administrative regions in 2017–2020 are presented. The status of Corynephoruscanescens on other territories near the eastern border of the area of its distribution is discussed.Keywords: floristic finding, new species, psammophytic vegetation, the Forest-Steppezone. Стаття узагальнює дані щодо поширення у Лівобережному Лісостепу України нового для цієї території виду Corynephoruscanescens(L.) P. Beauv., природний ареал якого охоплює Європу та Північну Африку. Зараз вид відомий з девʼяти локалітетів, які адміністративно розташовані у межах Київської (сім) і Полтавської (два) областей. За результатами аналізу геоботанічних описів псамофітних угруповань з участю цього виду встановлено, що у Київській області ділянки, на яких був знайдений Corynephoruscanescens, можна розглядати як фітоценози асоціації Corniculario aculeatae-Corynephoretum canescentis Steffen1931 з класу Koelerioglaucae-CorynephoreteacanescentisKlikainKlika& Novak1941 (союз CorynephorioncanescentisKlika, порядок CorynephoretaliacanescentisKlika1934), вони відзначаються добре вираженою двохярусною структурою зі значною участю мохів і лишайників, тоді як у Полтавськійобласті аналогічні ценози мають спрощену одноярусну будову з дуже розрідженим травʼяним покривом і розглядаються як окреме угруповання comm. Corynephoruscanescensу межах класу Koelerioglaucae-Corynephoreteacanescentis. З огляду на це, локалітети виду на Полтавщині автори вважають такими, які мають антропогенне походження, тоді як на Київщині вони є природними або принаймні природно-антропогенними. Наведені фітоценотичні таблиці геоботанічних описів, виконаних авторами. Обговорюється статус Corynephoruscanescensв інших регіонах біля східної межі його ареалу.Ключові слова: флористична знахідка, новий вид, псамофітна рослинність, лісостепова зона.

KIAM Russian Academy of Sciences, International Laboratory «Sensorika» conduct research and development of service robots for tasks of telemedicine. The developed mobile robot AMUR-307 is planned to be used in clinics to move various objects between the premises of the building, separated by thresholds, stairs and doors. The robot is controlled remotely via a radio channel from the operator's post. It is also intended to minimize operator interference and apply the developed algorithms for autonomous operation using an on-board computing device. To control robots of this type, a software and hardware microprocessor system was designed and manufactured and its comprehensive testing was performed. The solution allows you quickly make changes to the customer's requirements and deliver robots, integrating them into the existing infrastructure. The article presents the results of research and comparison of various ways to implement the robot, optimize its structure, replication technology and parallel programming using the GPU.

Introduction. Urothelial carcinoma of the upper urinary tract in Western countries of Erope and USA occurs in 1-2 cases per 100,000 populations. Nephroretrectomy remains the main method of treatment of this pathology, however, the role of organ-sparing surgeries increases with the bilateral localization of the tumor process. Due to the rarity of bilateral upper urinary tract lesions with urothelial cancer and the lack of data evaluating the results of organ-sparing surgeries in such situations, each clinical case is of interest. Materials and methods. The article describes a case of surgical treatment of a patient with non-invasive papillary urothelial carcinomas of both ureters and the pelvis of the right kidney, which were manifested by macrohematuria. Results. The diagnosis was confirmed by computer tomography (CT) and ureteroscopy with tumor biopsy, which revealed a neoplasm of the right kidney pelvis, multiple tumors of the distal part of the right ureter and a solitary neoplasm of the middle part of left ureter. The patient underwent laparoscopic nephrureterectomy on the right with transurethral resection of the bladder wall in the area of the mouth of the right ureter and endoscopic removal of the neoplasm in the middle third of the left ureter using laser energy. At the control examination 1,5 months after the surgical treatment, according to the results of CT, cystoscopy with biopsy of the bladder and ureteroscopy, as well as histological examination of the biopsies, no data for tumor growth were found. At CT 6 months after the surgery, no data for the recurrence of cancer were obtained. Сonclusions. This clinical observation demonstrates the technical feasibility and oncological feasibility of using organ-preserving surgical treatment for bilateral localization of low-grade urothelial carcinoma.

One of the fundamental problems of morphology, which has applied significance, is a comprehensive study of variants of individual-typological variability of the structures of the facial and cerebral parts of the skull, as well as the regularities of the interrelationships of individual components in the cranial system as a whole. An in-depth characteristic of the individual characteristics of the structures of the craniofacial complex makes it possible to improve the methods of diagnosis and treatment of dentoalveolar pathology. The article discusses the morphometric features of the dentition in people with a high type of palatine arch of the dolichopalatinal type, as well as their relationship with the shape of the dental arches and the size of the inter-incisal angle in physiological occlusion of permanent teeth. As a result of the study, the following pattern was determined: the transverse dimensions of the palatine fornix of the dolichopalatinal type have a stable relationship with the transverse dimensions of the dolichognathic dental arches and the value of the inter-incisal angle. The data obtained can be used in the clinic of orthodontics, orthopedic dentistry, and maxillofacial surgery to assess the parameters of the hard palate, diagnose pathological forms of the palatine fornix and determine the effectiveness of the treatment.

Raising the problem. The article reveals the issues of the evolution of means and techniques that affect the expression of the artistic and tectonic properties of architecture of the XXI century. The article notes the influence of the factors of the mid-19th − early 20th centuries, which gave impetus to the manifestation of the facade as a separate autonomous structure of the building body. The question of determining the typology of the latest modern systems is becoming increasingly important. The review and classification analysis of innovative facade systems of the XXI century has been little studied. This data is fragmented and improperly structured. Purpose. The main goals of the article are to analyze the existing varieties of facade systems, describe their characteristic qualities, identify and define various types of external fencing structures in the architecture of the XXI century. The plastic language of modern architecture is expressed in the classification of the evolution of external enclosing structures. This goal will be achieved by studying the facade systems of the XXI century in terms of their specific characteristics and functional purpose; analytical work. Conclusion. The architecture of the XXI century is primarily focused on the issues of ecology and energy efficiency, which are the main landmarks for our time. New structural systems and materials address these issues. The traditional concept of "tectonics" is applied to the artistic properties of how structures work, but in modern architecture, the structures themselves are usually hidden from the viewer. Therefore, the issue of "tectonics" in modern architecture does not yet have an unambiguous understanding, which requires further study. So, the types of structures of external fences given in the article require further broader research and determination of their classification features.

The subject of research in the article is a software security model. The aim of the work is to research the quality characteristics of the software and requirements for the software security in order to improve their safety. The article solves the following tasks: researching the shortcomings of the existing security model in order to identifyits main shortcomings; study of the quality characteristics of software that affect its security in order to identify the possibility of improving the quality of software. The following results were obtained: on the basis of the analysis of the existing model of software security, the main features of the attributes of this model were identified, their advantages and disadvantages were given. On the basis of the conducted analytical study, the necessity of improving the existing model of ensuring the security of software has been proved. Existing requirements for software and characteristics that affect its quality are considered. The characteristics of software security are highlighted, the indicators of which should be improved. Conclusions: a software security model has been studied. The need to develop this model is shown by introducing the possibility of adapting the existing requirements for the security of software tools throughout the entire life cycle of software development; the study of the quality characteristics of software showed that to ensure its security, it is necessary to improve the following characteristics: integrity, authentication, confidentiality, access control. However, it was shown that an increase in these characteristics can lead to a deterioration in other indicators of software quality: portability, maintainability, performance. Предметом дослідження в статті є модель забезпечення безпеки програмного забезпечення. Метою роботи є дослідження характеристик якості програмного забезпечення і вимог до безпеки програмних засобів з метою підвищення їх безпеки. У статті вирішуються наступні завдання: дослідження недоліків існуючої моделі забезпечення безпеки з метою виявлення основних її недоліків; дослідження характеристик якості програмного забезпечення, що впливають на її захищеність з метою виявлення можливості підвищення якість програмного забезпечення. Отримані наступні результати: на основі проведеного аналізу існуючої моделі забезпечення безпеки програмного забезпечення були виявлені основні особливості атрибути даної моделі, наведено їх переваги і недоліки. На основі проведеного аналітичного дослідження доведено необхідність вдосконалення існуючої моделі забезпечення безпеки програмних засобів. Розглянуто існуючі вимоги до програмного забезпечення та характеристики, що впливають на його якість. Виділено характеристики захищеності програмного забезпечення, показники яких повинні бути поліпшені. Висновки: досліджена модель забезпечення безпеки програмного забезпечення. Показана необхідність розвитку даної моделі шляхом введення можливості адаптації існуючих вимог до безпеки програмних засобів протягом усього життєвого циклу розробки програмного забезпечення; дослідження характеристик якості програмного забезпечення показало, що для забезпечення її захищеності необхідно підвищити наступні характеристик: цілісність, аутентифікація, конфіденційність, управління доступом. Однак, показано, що підвищення даних показників може спричинити за собою погіршення інших показників якості програмного забезпечення: переносимості, сопровождаемость, продуктивність.

This paper reports an analysis of the software (SW) safety testing techniques, as well as the models and methods for identifying vulnerabilities. An issue has been revealed related to the reasoned selection of modeling approaches at different stages of the software safety testing process and the identification of its vulnerabilities, which reduces the accuracy of the modeling results obtained. Two steps in the process of identifying software vulnerabilities have been identified. A mathematical model has been built for the process of preparing security testing, which differs from the known ones by a theoretically sound choice of the moment-generating functions when describing transitions from state to state. In addition, the mathematical model takes into consideration the capabilities and risks of the source code verification phase for cryptographic and other ways to protect data. These features generally improve the accuracy of modeling results and reduce input uncertainty in the second phase of software safety testing. An advanced security compliance algorithm has been developed, with a distinctive feature of the selection of laws and distribution parameters that describe individual state-to-state transitions for individual branches of Graphical Evaluation and Review Technique networks (GERT-networks). A GERT-network has been developed to prepare for security testing. A GERT-network for the process of checking the source code for cryptographic and other data protection methods has been developed. A graphic-analytical GERT model for the first phase of software safety testing has been developed. The expressions reported in this paper could be used to devise preliminary recommendations and possible ways to improve the effectiveness of software safety testing algorithms

In dynamic models, threats (vulnerabilities) can be viewed as a flow of temporary events. If the intervals of real-ized cyber threats are recorded, then a continuous log-list of events related to software security can be formed. In some cases and models, only the number of realized cyber threats for an arbitrary time interval can be recorded. In this case, the software response to threats can be represented only at discrete points. In static models, the implementation of cyber threats is not related to time, but the dependence of the number of errors or the number of implemented test cases (models by error area) on the characteristics of the input data (models by data area) is taken into account. The article analyzes the methods of mathematical formalization of the software penetration testing process. This software testing method is one of many approaches to testing the security of computer systems. The article substantiates the importance of the processes of preliminary prototyping and mathematical formalization. The classification is carried out and the advantages and disadvantages of the main approaches of mathematical modeling are highlighted. The list and main characteristics of dynamic and static models are presented. One of the negative factors of formalization is indicated - the neglect of the factors of a priori uncertainty in the safety parameters in static models. У динамічних моделях загрози (уразливості) Software можна розглядати як потік тимчасових подій. Якщо фіксуються інтервали реалізованих кіберзагроз, то може сформуватися безперервний log-лист подій, відносящіхся до безпеки Software. У ряді випадків і моделей може фіксуватися тільки число реалізованих кіберугроз за довільний інтервал часу. У цьому випадку реакція Software на загрози може бути представлена тільки в дискретних точках. У статичних моделях реалізацію кіберзагроз не пов'язують з часом, при цьому враховують завиності кількості помилок або число реалізованих тест-кейсів (моделі по області помилок) від характеристики вхідних даних (моделі по області даних).У статті проаналізовано методи математичної формалізації процесу тестування на проникнення програмного забезпечення. Цей метод тестування програмного забезпечення є одним із багатьох підходів до перевірки безпеки комп’ютерних систем. У статті обґрунтовано важливість процесів попереднього прототипування та математичної формалізації. Проведено класифікацію та висвітлено переваги та недоліки основних підходів математичного моделювання. Представлено перелік та основні характеристики динамічних та статичних моделей. Вказується один із негативних факторів формалізації - нехтування факторами апріорної невизначеності параметрів безпеки в статичних моделях.

Актуальной проблемой развития и повышения конкурентоспособности нефтегазовой отрасли является решение задачи надежного и эффективного электроснабжения технологических объектов новых месторождений и магистральных нефтегазопроводов, территориально удаленных от центральной электрической сети. Одним из эффективных способов решения данной проблемы является применение ветроэнергетических установок. Первоочередной задачей проектирования и технико-экономического обоснования применения ветроэнергетических установок является прогноз изменения скоростей ветра в месте установки электростанции. Стохастическая природа ветра и его большая изменчивость во времени и пространстве определяют высокую сложность данной задачи, для решения которой используют методы математического моделирования. Известные модели скорости ветра на основе цепей Маркова, авторегрессии и скользящего среднего не позволяют осуществлять варьирование шага моделирования, что ограничивает возможность их применения для имитационного моделирования режимов ветроэнергетических установок и энергетических систем на их основе. В статье предложена модель скорости ветра на основе стохастического дифференциального уравнения, устраняющая данный недостаток. Цель: разработка модели скорости ветра на основе стохастического дифференциального уравнения дробного процесса Орнштейна-Уленбека c периодической функцией среднего значения, обеспечивающей моделирование статических и динамических режимов работы ветроэнергетической установки на различных временных интервалах. Методы: математическое и компьютерное моделирование с использованием программной среды MatLab/Simulink. Результаты. Предложенная модель, в отличие от известных моделей подобного типа, воспроизводит как суточные, так и сезонные вариации скорости ветра, а также долговременную корреляционную зависимость моделируемого процесса, что позволяет осуществлять моделирование рабочих режимов ветроэнергетических установок на различных временных интервалах с требуемой дискретизацией. Валидация модели выполнена с использованием данных климатических наблюдений скорости ветра из электронного архива Всероссийского института гидрометеорологической информации. Адекватность модели подтверждена хорошей степенью соответствия моделируемых траекторий скорости ветра с данными фактических наблюдений, зарегистрированных на 518 метеостанциях, расположенных на территории России. Relevance. The urgent task of the technical and economic development of the Northern and Eastern regions of Russia is to provide reliable and efficient power supply to consumers, geographically located in remote, hard-to-reach areas. The use of wind power plants is a promising way to solve this problem. The primary task of the design and feasibility study of the use of wind power plants is to predict changes in wind speeds at the site of the power plant installation. The stochastic nature of the wind and its spatiotemporal variability explain the high complexity of this problem, for the solution of which the methods of mathematical modeling are used. The known models of wind speed based on Markov chains, autoregressive moving-average and other discrete models do not allow varying the time step, which does not allow their use for simulation of operating modes of wind turbines and wind energy systems. The article proposes a model of wind speed based on the stochastic differential equation which eliminates this drawback. The aim of the study is to construct wind speed model based on fractional Ornstein-Uhlenbeck process with a periodic long-term mean, which provides modeling of static and dynamic modes of operation of a wind power plant at different time intervals. Methods: mathematical and computer modeling using Matlab/Simulink software environment. Results. The proposed model, in contrast to the known SDE-based models, is able to produce autocorrelated wind speed trajectories with long-term dependence, daily and monthly variations to perform more detailed simulation of the operating modes of wind turbines at different time intervals with the required time step. The model was tested using the data of climatic observations of wind speed obtained from electronic archive of the All-Russian Institute of Hydrometeorological Information. The model adequacy was evaluated by comparing characteristics of simulated wind speed trajectories with actual observations collected at 518 weather stations located on territory of Russia.

We explore a unique dataset on individual investors’ online trading accounts to examine the determinants of their attention and its relation to portfolio performance. In particular, we investigate ...

Objective: to evaluate the outcomes of thrombectomy performed using different surgical techniques in renal cell carcinoma (RCC) patients with extensive tumor venous thrombosis.Materials and methods. This study included 345 RCC patients with extensive tumor venous thrombosis who underwent surgical treatment.The median age was 57 years (range: 16—79 years); the male-to-female ratio was 1:1.9. Two hundred and sixty patients (75.4 %) had their tumor thrombus originating from the right renal vein, 85 patients (24.6 %) — from the left renal vein. In 169 patients (49.0 %), the thrombus spread to the retrohepatic inferior vena cava (IVC), while in 176 patients (51.0 %), it spread above the diaphragm (to the intrapericardial IVC in 59 patients (17.1 %) and to the right heart cameras in 117 patients (33.9 %)). Regional metastases were found in 90 individuals (26.1 %), while distant metastases were observed in 124 patients (35.9 %). All patients underwent surgical treatment (radical in 251 patients (72.8 %) and cytoreductive — in 94patients (27.2 %)); the technique of vascular control and circulatory support was chosen individually. In 97 patients (28.1 %), the control over the cranial thrombus boarder did not require opening of the chest cavity; eleven patients (3.2 %) were operated on with cardiopulmonary bypass.Results. The median surgery time was 215 minutes; the median blood loss was 4500 mL. Intraoperative complications were registered in 209 patients (60.6 %) and postoperative complications were observed in 118 patients (35.1 %) (including those of grade I—II in 43 individuals (12.8 %) and grade III—V in 75 individual (22.3 %)). The in-hospital mortality rate was 10.7 % (37/345). At a median follow-up of 32.3 months, overall and diseasespecific survival rates among all patients were 51.9 % and 68.3 %, respectively; relapse-free survival rate in 226patients who have undergone radical surgeries and discharged from the hospital was 61.5 %; progression-free survival rate in 82 patients who have undergone cytoreductive surgery was 33.0 %. The method ofIVC control and circulatory support had no effect on both short-term and long-term treatment outcomes (p >0.05 for both).Conclusion. The use of minimally invasive techniques of vascular control and avoidance of cardiopulmonary bypass in carefully selected RCC patients with extensive tumor venous thrombosis do not worsen the outcomes of nephrectomy and thrombectomy.

Relevance. The need to increase vaccination coverage in order to eliminate measles in Russia and increase public confidence in vaccination requires constant monitoring of the quality of vaccines used for measles prevention. Aim. Analysis of laboratory quality parameters of commercial series of vaccines for measles prevention produced by JSC NPO Microgen, issued from 2015 to 2020, in comparison with the series issued in the period from 2002 to 2009. Materials and methods. The object of the study was a live measles culture vaccine and a live mumps-measles culture vaccine produced by JSC «NPO «Microgen». The quality analysis of vaccines was carried out according to the consolidated production and control protocols of 422 series of measles vaccine and 855 series of mumps-measles vaccine issued in 2015-2020, and 1043 series of measles vaccine and 902 series of mumpsmeasles vaccine issued in 2002-2009. Results and discussion. It is shown that the quality of the studied vaccines is stable during 16 years of monitoring. The sensitizing properties of both vaccines significantly decreased during the last 6 years of follow-up due to a decrease in the residual content of the antibiotic in the vaccination dose to less than the detection limit, as well as due to the low content of heterogeneous protein (bovine serum albumin). Conclusion. The quality of domestic vaccines for the prevention of measles and mumps meets who requirements; it is characterized by stability over 16 years of follow-up and minimal sensitizing properties. Information about the quality of domestic vaccines for the prevention of measles is an important argument for countering the antivaccination movement, which is a global problem and is recognized by who as one of the most important threats to the health of the world's population.

Background. Emergency physicians often have difficulty providing vascular access to patients in critical condition. In these conditions, intraosseous access has an advantage over traditional peripheral vein catheterization. Currently, intraosseous access is not widely used at the stage of emergency medical care.Aim. Analysis and generalization of current information on the use of the method of intraosseous access to emergency medicine.Materials and methods. We have found publications in Russian and international search engines (PubMed, eLIBRARY, etc.) over the past 20 years. Publications reflected current issues of intraosseous access application. 74 articles were found and 30 were selected for review.Results. Intraosseous access showed good results in patients with weakly expressed venous network at the stage of emergency medical care. The method has a simple technique of manipulation, does not have a large number of complications and contraindications. Doctors who have received training often use intraosseous access, taking into account the indications for use.Conclusion. Intraosseous access has an advantage over peripheral intravenous access in patients in critical condition at the stages of emergency care.

Cholecystocardial syndrome is a complex symptom complex, manifested by various disorders in the heart, the development of which is facilitated by the presence of gallstone disease and other diseases of the biliary tract in the patient. For many years, clinicians around the world have been studying the relationship between acute and chronic diseases of the biliary tract and the cardiovascular system. Often these disorders are detected during an attack of biliary colic, in which painful sensations in the region of the heart often occur, and in some cases they are equivalent to an attack of biliary colic. In real clinical practice, cholecystocardial syndrome is an actual syndrome of interest to therapists, cardiologists, gastroenterologists and surgeons. The review presents data on its prevalence, causes and mechanism of development, clinical manifestations. Data on the incidence of cholecystocardial syndrome in real clinical practice vary significantly, which depends on the interpretation of the concept of cholecystocardial syndrome. With the introduction of ultrasound into the widespread practice, the diagnosis of cholelithiasis was significantly simplified, therefore, cholecystocardial syndrome in the classical version described by S.P. Botkin, has been found less and less recently. With a broader consideration of the concept of cholecystocardial syndrome as a complex of clinical symptoms indicating the possibility of changes on the part of the cardiovascular system, in patients with a diagnosed pathology of the biliary tract, its occurrence is quite high. The analysis of domestic data on the problem of cholecystocardial syndrome in real clinical practice, combined with data obtained as a result of a search of foreign literature on electronic biomedical databases (PubMed, MEDLINE, Scopus, Google Scholar) suggests the allocation of another mechanism of its development, associated with cholestasis, high levels of circulating bile acids and activation of bile acid receptors, and allows us to consider its cholecystocardial syndrome not only as a diagnostic syndrome during differential diagnosis, but also as a syndrome reflecting the comorbidity of the pathology of CVS and the biliary tract.

А model of absorption of electromagnetic energy of radiofrequency range by biological tissues is described in the article. The problems of modeling the interaction of microwave radiation and biological tissues represented as multilayer structures are considered. Patch-antenna models for six sub-bands overlapping the 500–3500 MHz range are developed. The model of biological tissue was developed on the basis of MRI imaging, which allows for modeling under near real-life conditions. Based on the developed models of transceivers and biotissue, models have been created that allow to analyze the absorption of electromagnetic energy in the near- and far fields of the transmitter. From the results of modelling in the near field we can see that there are certain absorption maxima at frequencies of 750, 938, 1250 and 1357 MHz. Based on the results of the far field modeling it can be noted that in the range of 750 to 1000 MHz there is no absorption peak at 938 MHz. Also, as a result of the simulation, a decrease in the magnitude of absorption starting from 750 MHz was registered. Absorption peak absence is also observed in the area of 1357 MHz frequency. In the range of 2.5–3 GHz both in the near and far fields practically linear decrease of absorption value is observed. When analyzing the influence of structures' sizes on electromagnetic energy absorption in biological tissues, it was found that the nature of change in absorption value is a nonlinear value. In the range of 0.5–2 GHz both increase and decrease of absorption at thickening or thinning of layers is observed. It should also be noted that when the size of each layer increases by 10 %, the peak of absorption in the area of 1156 MHz frequency is observed. For the 2–3.5 GHz range there are no significant changes in the chart shape when the layer thickness changes.

Nanostructured all-inorganic metal halide perovskites have attracted considerable attention due to their outstanding photonic and optoelectronic properties. Particularly, they can exhibit room-temperature exciton-polaritons (EPs) capable of confining electromagnetic fields down to the subwavelength scale, enabling efficient light harvesting and guiding. However, a real-space nanoimaging study of the EPs in perovskite crystals is still absent. Additionally, few studies focused on the ambient-pressure and reliable fabrication of large-area CsPbBr3 microsheets. Here, CsPbBr3 orthorhombic microsheet single crystals were successfully synthesized under ambient pressure. Their EPs were examined using a real-space nanoimaging technique, which reveal EP waveguide modes spanning the visible to near-infrared spectral region. The EPs exhibit a sufficient long propagation length of over 16 μm and a very low propagation loss of less than 0.072 dB·μm-1. These results demonstrate the potential applications of CsPbBr3 microsheets as subwavelength waveguides in integrated optics.

Introduction Correction of the shape of the lower extremities for aesthetic purposes has specific features that are associated with the role of the patient in the treatment process and assessment of results. An important element is the relationship between the appearance of the limb and changes in the axes of the skeleton. Aim of study Assessment of many-years of experience in orthopedic correction of the shape of the lower extremities for aesthetic purposes, discussion of possibilities, analysis of problems and search for possible ways to prevent them. Methods The material of the study was 123 patients who underwent aesthetic surgical correction in the period from 2005 to 2020. Their results were followed in the period from 6 months to 11 years. In all cases, operations were performed simultaneously on both limbs. The total number of operations, thus, amounted to 246. The main indication for surgery was the so-called true O-shaped curvature (varus deformity) of the lower extremities. In all cases, the main elements of the operation were osteosynthesis with theIlizarov apparatus and osteotomy of the tibia. Wires and half-pins were used as transosseous elements. To assess the main reference lines and angles (RLA), X-ray examination of the lower extremities was performed with the capture of the hip and ankle joints. Results and discussion Corrective manipulations in the group of patients led to a change in the position of the main RLA. Before treatment, MAD value was 15 ± 7 mm, after correction MAD = -2 ± 4 mm, before surgery MPTA = 85 ± 40, after correction MPTA = 91 ± 20. Subjective satisfaction was reported in 114 (92.7 %) cases. Subjectively unsatisfactory results were recorded in 4 (3.3 %) cases; objectively unsatisfactory results were detected in 5 (4.1 %) cases. Conclusions Aesthetic surgery of the lower extremities is a part of orthopedic practice and has its specific features due to the goal of realizing the patient's wishes about changing the appearance of the lower extremities indirectly by performing operations on the skeleton. Corrective interventions should be considered as a preventive measure aimed at preventing the development of gonarthrosis in old age. The key to a good result is careful selection of candidates for surgery and their compliance, along with a thorough explanation of the principles and features of correction.

Models of the densities of states of amorphous graphene and graphene-like binary compounds are proposed. The models are used for estimations of the quantum capacitance of these structures. It is shown that amorphization reduces the quantum capacitance. The same effect takes place if graphene or a graphene-like compound interacts with a metal substrate. At the same time, in the case of a semiconductor (insulator) substrate, the quantum capacitance increases.

Hyperbolic phonon polaritons (HPhPs) are hybrid excitations of light and coherent lattice vibrations that exist in strongly optically anisotropic media, including two-dimensional materials (e.g., MoO3). These polaritons propagate through the material’s volume with long lifetimes, enabling novel mid-infrared nanophotonic applications by compressing light to sub-diffractional dimensions. Here, the dispersion relations and HPhP lifetimes (up to ≈12 ps) in single-crystalline α-MoO3 are determined by Fourier analysis of real-space, nanoscale-resolution polariton images obtained with the photothermal induced resonance (PTIR) technique. Measurements of MoO3 crystals deposited on periodic gratings show longer HPhPs propagation lengths and lifetimes (≈2×), and lower optical compressions, in suspended regions compared with regions in direct contact with the substrate. Additionally, PTIR data reveal MoO3 subsurface defects, which have a negligible effect on HPhP propagation, as well as polymeric contaminants localized under parts of the MoO3 crystals, which are derived from sample preparation. This work highlights the ability to engineer substrate-defined nanophotonic structures from layered anisotropic materials.

Laser-pulsed atom probe tomography (LAPT) is a materials characterization technique that has been widely applied in the study and characterization of III-nitride semiconductors. To date, most of th...