Bacterial Cellulose/Alginate Nanocomposite for Antimicrobial Wound Dressing

Development of novel wound dressing has attracted more and more attentions in recent years. Bacterial cellulose is a biopolymer of great potentials, which features a distinctive three-dimensional structure consisting of an ultrafine network of cellulos nanofibers. In the present study, nanocomposite bacterial cellulose films modified in situ by the addition of alginate during the static cultivation of Gluconacetobacter sucrofermentans B-11267 were produced and then enriching the polymer with an antimicrobial agent tetracycline hydrochloride. The structure of bacterial cellulose and nanocomposite was analyzed by AFM and FTIR. The FTIR spectra displayed the specified interaction between the hydroxyl group of cellulose and the carboxyl group of alginate. The produced bacterial cellulose and nanocomposite were analyzed to determine tensile modulus. The antibacterial activity of nanocomposites were investigated by disk diffusion method. The resulting nanocomposite have high antibiotic activity against Staphylococcus aureus and can be used in medicine as a wound dressing. Keywords: bacterial cellulose, Gluconacetobacter sucrofermentans, alginate, nanocomposite, antibacterial activity, wound dressin

Vertical distribution of ¹³⁷Cs in alluvial soils of the Lokna River floodplain (Tula oblast) long after the Chernobyl accident and its simulation

© 2016, Pleiades Publishing, Ltd.Profiles of vertical 137Cs distribution in alluvial meadow soils on the low and medium levels of the Lokna River floodplain (central part of the Plavsk radioactive spot in Tula oblast) 28 years after the Chernobyl fallout have been studied. A significant increase in the 137Cs pool is revealed on the low floodplain areas compared to the soils of interfluves due to the accumulation of alluvium, which hampers the reduction of the total radionuclide pool in alluvial soils because of radioactive decay. The rate of alluvium accumulation in the soil on the medium floodplain level is lower by three times on average. An imitation prognostic model has been developed, which considers the flooding and climatic conditions in the region under study. Numerical experiments have quantitatively confirmed the deciding role of low-mobile forms in the migration of maximum 137Cs content along the soil profile in the absence of manifested erosion–accumulation processes

Ferroelectric nanocomposites based on polymer ferroelectrics and graphene/oxide graphene: Computer modeling and SPFM experiments

The authors are thankful to the Russian Science Foundation (RSF grant # 16-19-10112) and to the Russian Foundation for Basic Researches (RFBR grants # 16-51-53917) for support. Prof. Xiang-Jian Meng expresses his gratitude to the National Natural Science Foundation of China (NNSFC) for support of the project: "The study on the new type of infrared detector based on ferroelectric tunnel junction"

Influence of Tocolytic Therapy with Hexoprenaline on Heart Rate Variability, Lipid Spectrum and Glycemic Level in Obese Pregnant Women

Background. Obesity is associated with the risk of spontaneous preterm birth. Hexoprenaline is the effective and most widely used tocolytic agent, possessing however a significant number of side effects. The effect of hexoprenaline tocolysis on heart rate variability, lipid spectrum and glycaemia level in obese pregnant women remain unexplored.Aim of the research. To study the effect of tocolytic therapy with hexoprenaline on heart rate variability, lipid spectrum and glycemic level in obese pregnant women.Materials and methods. The study included two groups of pregnant women with threatened preterm labor who received tocolysis with hexoprenaline. One group consisted of 68 obese patients, the other – 72 non-obese pregnant women (control group). Patients underwent Holter monitoring. Fasting serum glucose and lipids spectrum were measured before starting tocolytic therapy and after 24 hours of tocolysis.Results. In obese pregnant women with hexoprenaline infusion, the heart rate, the 24-hours number of supraventricular extrasystoles and ventricular extrasystoles during the day are significantly higher. Frequency domain parameters, very low frequency during the day, low frequency at night and 24-hours high frequency were significantly decreased than in control group. After a day of tocolysis in obese pregnant women, the level of total cholesterol, low density lipoproteins, triglycerides, and glucose significantly increases when compared with the results before therapy. For patients in the control group treated with hexoprenaline, only the concentration of high-density lipoproteins is increased.Conclusion. Obesity in pregnant women receiving hexoprenaline tocolysis is associated with low heart rate variability and an increase in the number of cardiac arrhythmias, as well as lipid disorders and an increase in glucose level

Piezoelectric, ferroelectric, optoelectronic and photo-catalytic phenomena from defect levels in hydroxyapatite by first-principles

The authors thank the Russian Foundation for Basic Researches (RFBR grant 19-01-00519 A) and to the Fundação para a Ciência e a Tecnologia (FCT) through project UID/CTM/50025/2013

Photoelectronic Properties of Chiral Self-Assembled Diphenylalanine Nanotubes: A Computational Study

Peptide nanotubes (PNT) of diphenylalanine (FF) have attracted considerable attention from researchers in the last decades. The chirality of FF monomers determines the kinetics of PNTs’ self-assembly and their morphology. The helical symmetry of PNTs causes significant intrinsic polarization and endows them with a unique combination of mechanical, electronic, and optical properties, as well as a strong piezoelectric effect useful for various applications. In this work, we used a combination of computer modeling and quantum chemical calculations to study the photoelectronic properties of FF PNTs of different chiralities. Using semiempirical methods implemented in the HyperChem and MOPAC packages, we calculated HOMO and LUMO energy levels and a band gap and their variations under the action of external and internal electric fields. We demonstrated that the photoelectronic properties of l- and d-FF PNTs are slightly different and may be related to the intrinsic electric field arising due to the internal polarization. The band gap of FF PNTs is within the ultraviolet range (400–250 nm) and can be tuned by an external electric field. These results open a way to create FF PNT-based solar-blind ultraviolet photodetectors and other electro-optic and electronic devices. © 2023 by the authors.Fundação para a Ciência e a Tecnologia, FCT; Russian Foundation for Basic Research, РФФИ: 19-01-00519_A, 20-51-53014_GFEN_AThe authors are grateful to the Russian Foundation for Basic Research, RFBR (grants 19-01-00519_A and 20-51-53014_GFEN_A). This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020, supported through the FCT/MEC (PIDDAC). Part of this work was supported by national funds (OE), through FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of article 23, of the Decree-Law 57/2016, of 29 August, changed by Law 57/2017, of 19 July. The computational parts of the study were completed within the framework of the noncommercial agreement on scientific and technical cooperation between the Institute of Mathematical Problems of Biology (IMPB)—branch of KIAM RAS, Russia and the Department of Physics of the University of Aveiro, Portugal. The authors are grateful for the opportunity to perform calculations using the computer cluster of IMPB RAS and the K-60 hybrid supercomputer installed at the KIAM RAS Shared Use Center

Using Chernobyl-derived 137Cs to document recent sediment deposition rates on the River Plava floodplain (Central European Russia)

Floodplain sedimentation is one of the most dynamic geomorphic processes within plain and lowland landscapes. There is generally a good understanding of longer term floodplain evolution, but quantitative information on overbank deposition rates for recent shorter timescales is lacking. This paper describes the application of Chernobyl-derived 137Cs to quantify floodplain aggradation rates for the River Plava (a small river draining a severely contaminated part of the upland region of Central European Russia), based on detailed sampling of four representative floodplain study sites. Two approaches have been employed for estimating post-Chernobyl (1986-2009) floodplain accumulation rates. The first was based simply on locating the Chernobyl fallout-associated 137Cs peak in overbank sediment sections. The second involved quantification of the increase in the total 137Cs inventory at individual sampling points associated with the post-Chernobyl deposition of contaminated suspended sediment. It has been shown that considerable local-scale variability of overbank deposition rates exists, with aggradation rates on the low level floodplain (6±1.2-14±2.8 mm year-1) exceeding by 1.5-3 times the values for the middle level floodplain (2±0.4-9±1.8 mm year-1) and by 3-6 times the values for the upper level floodplain (1±0.2-5±1.0 mm year-1) floodplain levels. Combining these estimates with information on the areas occupied by different floodplain levels within the 54 km long valley section, derived from detailed geomorphic surveys of the selected reaches, it has been estimated that about 9700±1950 t of sediment have been stored on floodplain during the 1986-2009 period. The role of floodplain storage in the overall basin sediment budget and conveyance losses within the main channel system have been evaluated. © 2012 John Wiley & Sons, Ltd

«Непрерывное библиотечно-информационное образование» – ежегодная конференция, вдохновлённая В. А. Минкиной, или О роли личности в истории

In March, 2021, Valentina A. Minkina would turn eighty. Valentina A. Minkina is a prominent scientist, doctor of pedagogy, Professor of Information Management Department that she headed from 1991 to 2004. In memory of Valentina Minkina, the Library and Information Faculty of Saint-Petersburg State Institute of Culture holds the annual International Scientific and Methodological Conference “Continuing LIS Education”. Due to the COVID-19 pandemic, many professional events had to move to online or were deferred to a later date, and this conference, too. It is hard to overestimate the contribution of Valentina Minkina made to the library science. The authors review in brief her research efforts as the leader of the library scientific school and a wonderful mentor. The authors also review the origins and development of the conference. Among other library professional forums, the conference is unique as it focuses on professional education and training staff for libraries and information organizations, which is due not in no small way to Minkina’s ideas and the faculty’s traditions. The most significant publications in the periodicals on the conference are listed.В марте 2021 г. исполнилось 80 лет со дня рождения В. А. Минкиной − известного учёного, доктора педагогических наук, профессора кафедры информационного менеджмента, которую она возглавляла с 1992 по 2004 г. В память Валентины Альфредовны на библиотечно-информационном факультете Санкт-Петербургского государственного института культуры ежегодно про- водится международная научно-методическая конференция «Непрерывное библиотечно-информационное образование». Вклад Валентины Альфредовны в развитие библиотековедения трудно переоценить. В статье дан краткий очерк о деятельности В. А. Минкиной как учёного, лидера научной школы и замечательного педагога. Авторы приводят основные этапы зарождения, становления и развития конференции, посвящённой памяти В. А. Минкиной. Эта конференция выделяется из множества других, проводимых в библиотечной сфере, поскольку здесь рассматриваются именно вопросы подготовки кадров для библиотечно-информационных учреждений, чему способствуют воплотившиеся в жизнь идеи Валентины Альфредовны и традиции кафедры

Influence of liposome forms of rhenium-platinum anti-tumor system on the proliferative activity of cancer cells

Уперше показано антипроліферативну активність реній-платинової системи на клітинах раку крові людини СЕМ-Т4. Найефективнішими виявилися експерименти, де використовувались обидва компоненти системи. Показано також перевагу ліпосомних форм порівняно з розчинами препаратів та переважний апоптотичний механізм загибелі клітин під дією системи.Впервые показана антипролиферативная активность рений-платиновой системы на клетках рака крови человека СЕМ-Т4. Наиболее эффективными оказались эксперименты, где использовались оба компонента системы. Показано также преимущество липосомных форм в сравнении с растворами препаратов и преимущественный апоптотический механизм гибели клеток под действием системы.First the antiproliferative activity of the antitumor system rhenium-platinum on the human blood cancer cells СЕМ-Т4 was shown. Experimental administration of both components of the system showed the most effectiveness. The advantages of liposomic forms in comparison with preparations solutions and dominating apoptotic mechanism of the cancer cells death under the treatment by the system were shown

Polarization switching and piezoresponse in PVDF/P(VDF-TrFE) ferroelectric films and multifunctional G/GO composites

Such composites can serve as a multifunctional molecular unit. Further models are in progress. The work is supported by RFBR grants # 15-01-04924, # 16-51-53017 and RSF grant #16-19-10112