The rapid growth of drug-resistant bacteria all over the world has given rise to a major research challenge, namely a search for alternative treatments to which bacteria will be unable to develop resistance. Photodynamic therapy is an approach of this kind. It involves the use of photosensitizers in combination with visible light at a certain wavelength to excite the former and generate reactive oxygen species. Various synthetic heterocyclic compounds are used as photosensitizers. Of these, derivatives of natural chlorophylls have a special place due to their properties. This review deals with the use of such compounds in antimicrobial PDT.

Vitamin D is a fat-soluble secosteroid that plays a significant role in the whole body, including the maxillofacial region. The discovery of its receptors in many cells and organs made it possible to reveal the participation of vitamin D not only in the regulation of calcium phosphate metabolism, but also in immune processes, in providing anti-inflammatory and antimicrobial effects, slowing down cell proliferation and stimulating differentiation. In this literature review, we demonstrate the association between low vitamin D levels and the development of recurrent aphthous stomatitis, the course and response to treatment of squamous cell carcinoma of the oral cavity, the severity of periodontal diseases, and the processes of osseointegration and bone remodeling during dental implantation and guided tissue regeneration. The aim of our article was to demonstate a possible connection between vitamin D level and the oral diseases that can be presented at an oral surgery appointment, which will help clinicians to reduce the risk of early dental implant failure, ensure favorable outcomes of augmentative operations, as well as decrease the destructive effects of severe periodontitis and other conditions throug knowledge and timely lab tests and endocrinologist prescriptions.

This article describes the manufacturing technology of biocompatible flexible strain-sensitive sensor based on Ecoflex silicone and multi-walled carbon nanotubes (MWCNT). The sensor demonstrates resistive behavior. Structural, electrical, and mechanical characteristics are compared. It is shown that laser radiation significantly reduces the resistance of the material. Through laser radiation, electrically conductive networks of MWCNT are formed in a silicone matrix. The developed sensor demonstrates highly sensitive characteristics: gauge factor at 100% elongation −4.9, gauge factor at 90° bending −0.9%/deg, stretchability up to 725%, tensile strength 0.7 MPa, modulus of elasticity at 100% 46 kPa, and the temperature coefficient of resistance in the range of 30–40 °С is −2 × 10−3. There is a linear sensor response (with 1 ms response time) with a low hysteresis of ≤3%. An electronic unit for reading and processing sensor signals based on the ATXMEGA8E5-AU microcontroller has been developed. The unit was set to operate the sensor in the range of electrical resistance 5–150 kOhm. The Bluetooth module made it possible to transfer the received data to a personal computer. Currently, in the field of wearable technologies and health monitoring, a vital need is the development of flexible sensors attached to the human body to track various indicators. By integrating the sensor with the joints of the human hand, effective movement sensing has been demonstrated.

Background: Numerous studies have shown an effect of rapidly spreading SARS-COV-2 on combined anxiety-depressive disorders and maladjustment syndrome occurrences. Objective: To determine the primary medical students’ reactive anxiety level and the final scores of their educational progress in distance learning during the SARS-COV-2 pandemic. Materials and Methods: The study involved 824 students at medical universities in Saratov and Moscow. The assessment of the reactive anxiety level was carried out according to the State-Trait Anxiety Inventory, STAI; the average score of students' academic performance was calculated according to the data of the technological platform "1C: Enterprise" version 8.4.1. The survey was completed during distance learning in May 2020. The quality of distance learning was compared to a similar score for 2019, when students were trained in a traditional way. Statistical analysis was conducted using Statistica 6.0. Results: It was shown the presence of moderately severe disorders among the primary medical students according to the average score of reactive anxiety (43.28 ± 12.85), that expressed more in females s (p<0.05), After distance learning, lasting 25% of the whole course, the overall performance score in theoretical knowledge did not change significantly (p>0.05) but the practical skills suffered much especially in time trend (p<0.05). Novelty: It was found that a high level of the reactive anxiety negatively affects the students' adaptive capabilities and the education quality. The specificity of programs at different faculties can determine the state of the students' psychological status. Findings:Timely transition to online classes during pandemics helps to preserve the students' mental well-being and the quality of the educational process. The duration of distance learning for a practical course should not exceed 25% of the whole course. Doi: 10.28991/esj-2021-SPER-07 Full Text: PDF