180 results match your criteria: "Saint-Petersburg Electrotechnical University[Affiliation]"

The processes of electrochemical deposition of Ni on vertically aligned GaAs nanowires (NWs) grown by molecular-beam epitaxy (MBE) using Au as a growth catalyst on Si(111) substrates were studied. Based on the results of electrochemical deposition, it was concluded that during the MBE synthesis of NWs the self-induced formation of conductive channels can occur inside NWs, thereby forming quasi core-shell nanowires. Depending on the length of the channel compare to the NW heights and the parameters of electrochemical deposition, the different hybrid metal-semiconductor nanostructures, such as Ni nanoparticles on GaAs NW side walls, Ni clusters on top ends of GaAs NWs, core-shell Ni/GaAs NWs, were obtained.

View Article and Find Full Text PDF

Mass-spectrometry-based assays nowadays play an essential role in biomedical research and clinical applications. There are different types of commercial mass spectrometers on the market today, and triple quadrupole (QqQ) is one of the time-honored systems. Here, we overview the main areas of QqQ applications in biomedicine and assess the current level, evolution, and trends in the use of QqQ in these areas.

View Article and Find Full Text PDF

Neurons become more vulnerable to stress factors with age, which leads to increased oxidative DNA damage, decreased activity of mitochondria and lysosomes, increased levels of p16, decreased LaminB1 proteins, and the depletion of the dendritic tree. These changes are exacerbated in vulnerable neuronal populations during the development of neurodegenerative diseases. Glu-Asp-Arg (EDR) and Lys-Glu-Asp (KED), and Ala-Glu-Asp-Gly (AEDG) peptides have previously demonstrated neuroprotective effects in various models of Alzheimer's disease.

View Article and Find Full Text PDF

It is commonly accepted that dietary nucleotides should be considered as essential nutrients originating mainly but not exclusively from meat and fish dishes. Most research in food science related to nutrition nucleotides is focused on raw products, while the effects of thermal processing of ready-to-eat food on nucleotide content are largely overlooked by the scientific community. The aim of this study is to investigate the impact of thermal processing and cold storage on the content of dietary nucleotides in freshly prepared and canned ready-to-eat meat and fish food.

View Article and Find Full Text PDF

Existing attribute-based proxy re-encryption schemes suffer from issues like complex access policies, large ciphertext storage space consumption, and an excessive authority of the authorization center, leading to weak security and controllability of data sharing in cloud storage. This study proposes a Weighted Attribute Authority Multi-Authority Proxy Re-Encryption (WAMA-PRE) scheme that introduces attribute weights to elevate the expression of access policies from binary to multi-valued, simplifying policies and reducing ciphertext storage space. Simultaneously, the multiple attribute authorities and the authorization center construct a joint key, reducing reliance on a single authorization center.

View Article and Find Full Text PDF

Circular SAW Resonators: Influence of Sensitive Element Dimensions on Strength Characteristics and First Experimental Samples.

Sensors (Basel)

July 2024

Department of Laser Measuring and Navigation Systems, Faculty of Information Measurement and Biotechnical Systems, Saint Petersburg Electrotechnical University (LETI), Popova Str., h. 5, 197376 Saint Petersburg, Russia.

In preceding research endeavors, the frequency characteristics of a ring resonator on surface acoustic waves made of various materials were studied. Investigations encompassed fixation techniques within the housing, the impact of external variables on these components, and the most efficient configuration of the interdigital transducer within the ring resonator to curtail bandwidth. This current study is dedicated to investigating the correlation between sensitivity and the highest measurable acceleration concerning the dimensions of these sensitive elements.

View Article and Find Full Text PDF

The present paper discusses the scientific and technical problem of optimizing the design and characteristics of a new type of solid-state sensors for motion parameters on bulk acoustic waves in order to increase the signal-to-noise ratio and the detectability of an informative signal against the background of its own noise and interference. Criteria for choosing materials for structural elements, including piezoelectric transducers of the sensitive element, were identified; a corresponding numerical simulation was performed using the developed program; and experimental studies according to the suggested method were carried out to validate the obtained analytical and calculated positions. The experimental results revealed the correctness of the chosen criteria for the optimization of design parameters and characteristics, demonstrated the high correlation between the results of modeling and field studies, and, thus, confirmed the prospects of using this new type of solid-state acoustic sensors of motion parameters in the navigation and control systems of highly dynamic objects.

View Article and Find Full Text PDF

We study recombination processes in nitride LEDs emitting from 270 to 540 nm with EQE ranging from 4% to 70%. We found a significant correlation between the LEDs' electro-optical properties and the degree of nanomaterial disorder (DND) in quantum wells (QWs) and heterointerfaces. DND depends on the nanoarrangement of domain structure, random alloy fluctuations, and the presence of local regions with disrupted alloy stoichiometry.

View Article and Find Full Text PDF

TiO-based photocatalysts from type-II to S-scheme heterojunction and their applications.

J Colloid Interface Sci

December 2024

College of Chemistry, Nankai University, Tianjin 300071, Tianjin, China. Electronic address:

Photocatalysis is a promising sustainable technology to remove organic pollution and convert solar energy into chemical energy. Titanium dioxide has drawn extensive attention in this field owing to its high activity under UV light, good chemical stability, large availability, low price and low toxicity. However, the poor quantum efficiency derived from fast electron/hole recombination, the limited utilization of sunlight, and a weak reducing ability still hinder its practical application.

View Article and Find Full Text PDF

Microbial Biofilms: Features of Formation and Potential for Use in Bioelectrochemical Devices.

Biosensors (Basel)

June 2024

Federal Research Center (Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences), G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino 142290, Russia.

Microbial biofilms present one of the most widespread forms of life on Earth. The formation of microbial communities on various surfaces presents a major challenge in a variety of fields, including medicine, the food industry, shipping, etc. At the same time, this process can also be used for the benefit of humans-in bioremediation, wastewater treatment, and various biotechnological processes.

View Article and Find Full Text PDF

Crystal-Inspired Cellular Metamaterials and Triply Periodic Minimal Surfaces.

Biomimetics (Basel)

May 2024

Infochemistry Scientific Center (ISC), ITMO University, 9 Lomonosova St., St. Petersburg 191002, Russia.

Triply periodic minimal surfaces (TPMSs) are found in many natural objects including butterfly wings, sea urchins, and biological membranes. They simultaneously have zero mean curvature at every point and a crystallographic group symmetry. A metamaterial can be created from such periodic surfaces or used as a reinforcement of a composite material.

View Article and Find Full Text PDF
Article Synopsis
  • The article explores using bioelectrography to diagnose internal organ issues, highlighting limitations of current methods in automatically detecting diseases.
  • It discusses the development of a new method and software that employ various machine-learning classifiers, improving disease identification in internal organs.
  • Among these models, HyperTab, logistic regression, and xgboost perform best, achieving a 60-70% f1-score, which can enhance disease detection during screenings and reduce medical staff workload.
View Article and Find Full Text PDF

Biofilms based on bacteria () and () and yeast () were used for novel biosensor creation for rapid biochemical oxygen demand (BOD) monitoring. Based on the electrochemical measurement results, it was shown that the endogenous mediator in the matrix of and biofilms and ferrocene form a two-mediator system that improves electron transport in the system. Biofilms based on and had a high biotechnological potential for BOD assessment; bioreceptors based on such biofilms had high sensitivity (the lower limits of detectable BOD concentrations were 0.

View Article and Find Full Text PDF

Peptides show high promise in the targeting and intracellular delivery of next-generation biotherapeutics. The main limitation is peptides' susceptibility to proteolysis in biological systems. Numerous strategies have been developed to overcome this challenge by chemically enhancing the resistance to proteolysis.

View Article and Find Full Text PDF

Josephson junctions (JJs) are superconductor-based devices used to build highly sensitive magnetic flux sensors called superconducting quantum interference devices (SQUIDs). These sensors may vary in design, being the radio frequency (RF) SQUID, direct current (DC) SQUID, and hybrid, such as D-SQUID. In addition, recently many of JJ's applications were found in spiking models of neurons exhibiting nearly biological behavior.

View Article and Find Full Text PDF

Introduction: Factors such as coronavirus neurotropism, which is associated with a massive increase in pro-inflammatory molecules and neuroglial reactivity, along with experiences of intensive therapy wards, fears of pandemic, and social restrictions, are pointed out to contribute to the occurrence of neuropsychiatric conditions.

Aim: The aim of this study is to evaluate the role of COVID-19 inflammation-related indices as potential markers predicting psychiatric complications in COVID-19.

Methods: A total of 177 individuals were examined, with 117 patients from a temporary infectious disease ward hospitalized due to COVID-19 forming the experimental group and 60 patients from the outpatient department showing signs of acute respiratory viral infection comprising the validation group.

View Article and Find Full Text PDF

Advanced technique of myocardial no-reflow quantification using indocyanine green.

Biomed Opt Express

February 2024

Institute of Experimental Medicine, Almazov National Medical Research Centre, 2 Akkuratova Str., 197341 Saint Petersburg, Russia.

The post-ischemic no-reflow phenomenon after primary percutaneous coronary intervention (PCI) is observed in more than half of subjects and is defined as the absence or marked slowing of distal coronary blood flow despite removal of the arterial occlusion. To visualize no-reflow in experimental studies, the fluorescent dye thioflavin S (ThS) is often used, which allows for the estimation of the size of microvascular obstruction by staining the endothelial lining of vessels. Based on the ability of indocyanine green (ICG) to be retained in tissues with increased vascular permeability, we proposed the possibility of using it to assess not only the severity of microvascular obstruction but also the degree of vascular permeability in the zone of myocardial infarction.

View Article and Find Full Text PDF

Impedimetric biosensors represent a powerful and promising tool for studying and monitoring biological processes associated with proteins and can contribute to the development of new approaches in the diagnosis and treatment of diseases. The basic principles, analytical methods, and applications of hybrid impedimetric biosensors for express protein detection in biological fluids are described. The advantages of this type of biosensors, such as simplicity and speed of operation, sensitivity and selectivity of analysis, cost-effectiveness, and an ability to be integrated into hybrid microfluidic systems, are demonstrated.

View Article and Find Full Text PDF

The split-cylinder resonator method was adapted to measure the microwave properties (dielectric permittivity and loss tangent) of thin ferroelectric films on a dielectric substrate. The mathematical model for calculating the resonance frequency of the split-cylinder resonator was adjusted for the "ferroelectric film-substrate" structure. An approach for correcting the gap effect based on calibrating with a single-layer dielectric was introduced and used to study two-layer dielectrics.

View Article and Find Full Text PDF

Behavioral Modeling of Memristors under Harmonic Excitation.

Micromachines (Basel)

December 2023

Department of Electrical Engineering Theory, Saint Petersburg Electrotechnical University "LETI", 197022 St. Petersburg, Russia.

Memristors are devices built on the basis of fourth passive electrical elements in nanosystems. Because of the multitude of technologies used for memristor implementation, it is not always possible to obtain analytical models of memristors. This difficulty can be overcome using behavioral modeling, which is when mathematical models are constructed according to the input-output relationships on the input and output signals.

View Article and Find Full Text PDF

Endometriosis is characterized by a condition where endometrial tissue grows outside the uterine cavity. The mechanisms of endometrium growth during endometriosis might be similar to the development of a tumor. The kisspeptin (KISS1) gene was initially discovered as a suppressor of metastasis.

View Article and Find Full Text PDF

This manuscript presents an algorithmic approach to cooperation in biological systems, drawing on fundamental ideas from statistical mechanics and probability theory. Fisher's geometric model of adaptation suggests that the evolution of organisms well adapted to multiple constraints comes at a significant complexity cost. By utilizing combinatorial models of fitness, we demonstrate that the probability of adapting to all constraints decreases exponentially with the number of constraints, thereby generalizing Fisher's result.

View Article and Find Full Text PDF

The aim of the study was to identify the features of diagnosis and treatment of sphenoid sinus diseases in patients over 60 years old. Clinical manifestations, results of endoscopic and radiological examination methods, and surgical intervention tactics were compared between elderly patients and younger patients (aged 18-59 years) who sought treatment for sphenoiditis in I.P.

View Article and Find Full Text PDF

The concepts of fragility and resilience are often used together to describe elderly people with reduced physical activity. While fragility, which develops with the aging of the body, is a biological syndrome of a decrease in the stressors response resulting from cumulative regression in many physiological systems, and age related a comprehensive assessment of the ability resistance to stress. In this regard, it is important to develop systems and scales for the identification groups of risk among the elderly.

View Article and Find Full Text PDF
Article Synopsis
  • Agriculture is increasingly leveraging data through artificial intelligence (AI) and the Internet-of-Things (IoT) to improve practices like rainfall prediction and fruit health monitoring.
  • The proposed intelligent agriculture management system incorporates various sensors and uses advanced AI models, including Convolutional Neural Networks (CNN) and Long Short-Term Memory (LSTM) layers, for accurate predictions.
  • The entire system operates in the cloud and can be accessed via a dedicated application, enhancing its usability in agricultural settings.
View Article and Find Full Text PDF