Search

The aim of the study was to evaluate predictors of cardiac conduction disturbance associated with increased risk of temporary and permanent pacemaker implantation after endovascular aortic valve replacement (TAVR). Material and methods. We analyzed patients who underwent surgical treatment for aortic valve replacement by endovascular treatment in Krasnoyarsk Regional Clinical Hospital from January 2018 to May 2023. The total number of people included in the study is 157. Results and discussion. The association between the occurrence of atrioventricular block of II–III degree, left bundle branch block and atrial fibrillation after TAVR implantation, which required temporary pacemaker implantation and permanent pacemaker implantation, was revealed. Atrioventricular block of grade II-III was first detected in 11 (13.3 %) patients after TAVR, left bundle branch block – in 22 (26.5 %) and atrial fibrillation – in 11 (13.3 %). The need for temporary pacing during TAVR was necessary in 35 (23.6 %) patients. 34 (23.0 %) patients had a temporary pacemaker placed within the first 2 days after surgical intervention and 1 patient (0.7 %) after 3 days. Regression analysis revealed 6 significant risk factors for temporary pacemaker implantation: left bundle branch block (p = 0.002), atrial fibrillation (p = 0.030), 1st degree atrioventricular block (p = 0.032), age (p = 0.012), female gender (p = 0.033) and history of acute myocardial infarction (p = 0.024). Permanent pacemaker implantation was performed in 7 (4.5 %) patients in the period from 4 to 20 days, including 6 (85.7 %) patients due to complete atrioventricular block and 1 (14.3 %) patient due to sinus node dysfunction. Permanent pacemaker was implanted to five (3.2 %) patients in the period from 6 months to 3.6 years, including 3 (1.9 %) patients due to complete atrioventricular block and 2 (1.3 %) patients due to sinus node dysfunction. Regression analysis revealed 2 significant risk factors for permanent pacemaker implantation: presence of atrial fibrillation before surgical intervention (p = 0.002; r = 0.160) and presence of left bundle branch block before TAVR (p = 0.037; r = 0.108). Conclusions. Identification of predictors of atrioventricular block of II–III degrees after TAVR will facilitate timely temporary pacing and permanent pacemaker implantation to prevent complications due to bradyarrhythmias.

This paper explores the use of deep learning techniques to improve the performance of web application firewalls (WAFs), describes a specific method for improving the performance of web application firewalls, and presents the results of its testing on publicly available CSIC 2010 data. Most web application firewalls work on the basis of rules that have been compiled by experts. When running, firewalls inspect HTTP requests exchanged between client and server to detect attacks and block potential threats. Manual drafting of rules requires experts' time, and distributed ready-made rule sets do not take into account the specifics of particular user applications, therefore they allow many false positives and miss many network attacks. In recent years, the use of pretrained language models has led to significant improvements in a diverse set of natural language processing tasks as they are able to perform knowledge transfer. The article describes the adaptation of these approaches to the field of information security, i.e. the use of a pretrained language model as a feature extractor to match an HTTP request with a feature vector. These vectors are then used to train the classifier. We offer a solution that consists of two stages. In the first step, we create a deep pre-trained language model based on normal HTTP requests to the web application. In the second step, we use this model as a feature extractor and train a one-class classifier. Both steps are performed for each application. The experimental results show that the proposed approach significantly outperforms the classical Mod-Security approaches based on rules configured using OWASP CRS and does not require the involvement of a security expert to define trigger rules.

BACKGROUND: The development of new scintillation materials based on fluorescent nanocrystals with a perovskite structure of CsPbBr3 composition and CdSe/ZnS quantum dots is a pressing topic that is being pursued by numerous scientific groups [1–4]. Both of these materials have a high potential for application in this role due to their excellent fluorophore properties, with a quantum yield of luminescence of approximately 100%. Additionally, they possess high values of the effective atomic Zeff number. The photoelectric cross section is dependent on Zeff as (Zeff)5, while the magnitude of X-ray absorption is dependent on Zeff as (Zeff)4/(AE3), where A is the atomic mass of the substance absorbing the γ-quantum and E is the energy of the X-ray photon [5]. AIM: The aim of the study was to develop a technique for fabricating scintillators based on quantum dots and polymer matrices with a high degree of transparency, high temporal stability of luminescence quantum yield, and short luminescence decay times (time of illumination or average lifetime of the substance in the excited state) for gamma-ray registration. MATERIALS AND METHODS: A HAMAMAMATSU R7400U-6 photomultiplier tube was employed to register scintillation signals. A 137Cs source with a γ-quantum energy of 661.7 keV was used as a source of ionizing radiation. RESULTS: At irradiation with γ-quanta of 137Cs isotope samples based on poly(para-methylstyrene) matrix cross-linked with divinylbenzene molecules (10% wt%), activated with naphthalene (10%, primary acceptor), anthracene (1%) and quantum dots/perovskite nanocrystals (0, 1–1.0%, re-emitter), the energy spectrum showed effective Compton scattering of gamma-quanta in matter on atoms included in quantum dots/perovskite nanocrystals. The study revealed that samples devoid of inorganic elements, including quantum dots and perovskite nanocrystals, do not exhibit the Compton effect for gamma-quanta. Furthermore, the paramethylstyrene matrix serves to safeguard perovskite nanocrystals from external influences. The photoluminescence quantum yield of bulk composite materials based on perovskite nanocrystals of the CsPbBr3 composition and poly(paramethylstyrene) remains constant over an extended period, with minimal fluctuations within the margin of error. CONCLUSIONS: Experimental evidence has demonstrated that quantum dots and perovskite nanocrystals encapsulated in various polymer matrices exhibit scintillator properties when subjected to ionizing radiation. The fabricated samples of perovskite nanocrystals/quantum dots and various polymers have been identified as the most promising candidates for use as scintillation material for the registration of X-ray and gamma radiation.

This study introduces results of lithological, petrophysical and geochemical investigation of Lower Cretaceous (K1 ) and Middle Jurassic (J2 a-b) rocks of East Pre-Caucasian basin.According to pyrolytic and bituminological studies method of separate determination of kerogen and bitumen concentration been developed. In accordance with this method differentiation of organic matter components in different lithotypes of rocks been described. Also relationship between bitumen and kerogen concentrations been revealed.The majority of samples have poor to fair organic richness and poor source potential. Kerogen type is commonly presented by type III and stages of maturity characterized by stages PC3 to MC3 . Bitumen compounds have low concentrations of asphaltenes and aromatic hydrocarbons and mainly contains light and heavy resins.Based on petrophysical and geochemical studies a close relationship between the concentration of organic carbon and the weight concentration of potassium nuclides was obtained. This relationship indicates that kerogen in the sediments under consideration is associated with clay minerals, which is also confirmed by the mineral composition of the rocks.

Aircraft contrails exhibit optical properties similar to those of natural high-level clouds (HLCs) and also form persistent cirrus cloudiness. This paper outlines a methodology for detecting and identifying contrails based on the joint analysis of aircraft trajectories (ADS-B monitoring), the vertical profiles of meteorological parameters (radiosonde observation (RAOB) and ERA5 reanalysis), and polarization laser sensing data obtained with the matrix polarization lidar. The potential application of ERA5 reanalysis for determining contrail drift parameters (azimuth, speed, distance, duration, and time of the contrail appearance above the lidar) and interpreting atmospheric polarization laser sensing data in terms of the presence of crystalline ice particles and the assessment of the degree of their horizontal orientation is demonstrated. In the examined case (6 February 2023; Boeing 777-F contrail; flight altitude of 10.3 km; HLC altitude range registered with the lidar of 9.5–10.3 km), the difference in the times of appearance of the contrail over the lidar, calculated from RAOB and ERA5 data, did not exceed 10 min. The difference in the wind direction was 12°, with a wind speed difference of 2 m/s, and the drift distance was approximately the same at about 30 km. The demonstrated technique will allow the experimental dataset of contrail optical and microphysical characteristics to be enhanced and empirical relationships between these characteristics and meteorological quantities to be established.

The results of the development of a high-voltage semiconductor voltage generator (based on IGBT transistors) with a pulse transformer and the results of experiments on generating a capillary discharge using it on a compact gas-discharge source capable of generating pulses of soft X-ray radiation (SXR) in the area of the socalled «water window» - with wavelength in the range of 2.4...4.4 nm. Methods for designing a high-voltage pulse voltage pulse generator are described: theoretical calculations and results of modeling the electrical circuit diagram in the LTSpice software package, the developed design of a pulse transformer based on N87 ring ferrites and the generator itself is described, the results of its operation as part of a compact gas-discharge radiation source are presented and analyzed. The prospects of using such a high-voltage generator (with semiconductor transistor switches) with a pulse transformer as part of a soft X-ray radiation source are shown due to its technical and operational features: the developed generator is capable of operating from an alternating current network of 380 V/50 Hz in a frequency-burst mode (with a repetition rate of the generated voltage pulses up to 600 Hz) and charges the capillary capacitance of the SXR source to a voltage of more than 20 kV in a time of about 4 μs, has small dimensions, does not create pulsed high-frequency interference and false alarms, and also has stable output (amplitude-temporary) parameters.

The combination of micro- or nanofluidics and strong light–matter coupling has gained much interest in the past decade, which has led to the development of advanced systems and devices with numerous potential applications in different fields, such as chemistry, biosensing, and material science. Strong light–matter coupling is achieved by placing a dipole (e.g., an atom or a molecule) into a confined electromagnetic field, with molecular transitions being in resonance with the field and the coupling strength exceeding the average dissipation rate. Despite intense research and encouraging results in this field, some challenges still need to be overcome, related to the fabrication of nano- and microscale optical cavities, stability, scaling up and production, sensitivity, signal-to-noise ratio, and real-time control and monitoring. The goal of this paper is to summarize recent developments in micro- and nanofluidic systems employing strong light–matter coupling. An overview of various methods and techniques used to achieve strong light–matter coupling in micro- or nanofluidic systems is presented, preceded by a brief outline of the fundamentals of strong light–matter coupling and optofluidics operating in the strong coupling regime. The potential applications of these integrated systems in sensing, optofluidics, and quantum technologies are explored. The challenges and prospects in this rapidly developing field are discussed.

6-thioguanine (6-TG) is an antimetabolite drug of purine structure, approved by the FDA for the treatment of acute myeloid lesukemia, and it is of interest in treating other diseases. The interaction of drugs with matrices is of interest to achieving a delayed, sustained, and local release. The interaction of 6-TG with an aluminum metal–organic framework (Al-MOF) DUT-4 is studied using a novel experimental approach, namely, mechano-chemistry by liquid-assisted grinding (LAG). The bonding of 6-TG to the DUT-4 matrix in the composite (6-TG)(DUT-4) was studied using ATR-FTIR spectroscopy and XRD. This interaction involves amino groups and C and N atoms of the heterocyclic ring of 6-TG, as well as the carboxylate COO− and (Al)O-H groups of the matrix, indicating the formation of the complex. Next, an in vitro delayed release of 6-TG was studied from composite powder versus pure 6-TG in phosphate buffered saline (PBS) at 37 °C. Herein, an automated drug dissolution apparatus with an autosampler was utilized, and the molar concentration of the released 6-TG was determined using an HPLC–UV analysis. Pure 6-TG shows a quick (