Lignin-Based Nonviral Gene Carriers Functionalized by Poly[2-(Dimethylamino)ethyl Methacrylate]: Effect of Grafting Degree and Cationic Chain Length on Transfection Efficiency

Lignin is a natural renewable biomass resource with great potential for applications, while its development into high value-added molecules or materials is rare. The development of biomass lignin as potential nonviral gene delivery carriers was initiated by our group through the “grafting-from” approach. Firstly, the lignin was modified into macroinitiator using 2-bromoisobutyryl bromide. Then cationic polymer chains of poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) were grown from the lignin backbone using atom transfer radical polymerization (ATRP) to yield lignin-PDMAEMA graft copolymers (LPs) with branched structure. To gain a deep understanding of the relationship between the nonviral gene transfection efficiency of such copolymers and their structural and compositional factors, herein eight lignin-based macroinitiators with different modification degrees (MDs, from 3.0 to 100%) were synthesized. Initiated by them, a series of 20 LPs were synthesized with varied structural factors such as grafting degree (GD, which is equal to MD, determining the cationic chain number per lignin macromolecule), cationic chain length (represented by number of repeating DMAEMA units per grafted arm or degree of polymerization, DP) as well as the content of N element (N%) which is due to the grafted PDMAEMA chains and proportional to molecular weight of the LPs. The in vitro gene transfection capability of these graft copolymers was evaluated by luciferase assay in HeLa, COS7 and MDA-MB-231cell lines. Generally, the copolymers LP-12 (N% = 7.28, MD = 36.7%, DP = 13.6) and LP-14 (N% = 6.05, MD = 44.4%, DP = 5.5) showed good gene transfection capabilities in the cell lines tested. Overall, the performance of LP-12 was the best among all the LPs in the three cell lines at the N/P ratios from 10 to 30, which was usually several times higher than PEI standard. However, in MDA-MB-231 at N/P ratio of 30, LP-14 showed the best gene transfection performance among all the LPs. Its gene transfection efficiency was ca. 11 times higher than PEI standard at this N/P ratio. This work demonstrated that, although the content of N element (N%) which is due to the grafted PDMAEMA chains primarily determines the gene transfection efficiency of the LPs, it is not the only factor in explaining the performance of such copolymers with the branched structure. Structural factors of these copolymers such as grafting degree and cationic chain length could have a profound effect on the copolymer performance on gene transfection efficiency. Through carefully adjusting these factors, the gene transfection efficiency of the LPs could be modulated and optimized for different cell lines, which could make this new type of biomass-based biomaterial an attractive choice for various gene delivery applications.

The characteristics of microplasma discharge propagation over the titanium surface covered with a thin oxide film

The propagation and structure of a microplasma discharge initiated in vacuum by a pulsed plasma flow with a density of 1013 cm–3 on the surface of a titanium sample covered with a thin continuous dielectric titanium oxide film with a shickness of 2–6 nm were studied experimentally when the electric current of the discharge changes from 50 A to 400 A. It was found that the microplasma discharge glow visually at the macroscale has a branched structure of the dendrite type, which at the microscale consists of a large number of brightly glowing “point” formations – cathode spots localized on the metal surface. The resulting erosion structure on the titanium surface is visually “identical” to the structure of the discharge glow and consists of a large number of separate non-overlapping microcraters with characteristic sizes from 0.1–3 μm, which are formed at the sites of localization of cathode spots at distances of up to 20 μm from each other. It was found that the propagation of a single microplasma discharge over the titanium surface covered with a thin oxide film a thickness of 2–6 nm occurs at an average velocity of 15–70 m/s when the amplitude of the discharge electric current changes in the range of 50–400 A. In this case, the microplasma discharge propagation on the microscale has a “jumping” character: the plasma of “motionless” burning cathode spots, during their lifetime 1 μs, initiates the excitation of new microdischarges, which create new cathode spots at localization distances of 1–20 μm from the primary cathode spots. This process repeated many times during a microplasma dis- charge pulse with a duration from 0.1 ms to 20 ms.

Purification, Structural Characterization, and Anti-Inflammatory Effects of a Novel Polysaccharide Isolated from Orostachys fimbriata

The present study elucidated the structural characteristics and anti-inflammatory activity of a novel polysaccharide isolated from Orostachys fimbriata, which is a traditional Chinese medicinal plant. O. fimbriata polysaccharide (OFP) was extracted and subsequently purified by chromatography using a DEAE cellulose-52 and Sephadex G-75 column. The molecular weight was determined as 6.2 kDa. HPGPC and monosaccharide composition analysis revealed a homogeneous polysaccharide containing only Glc. Chromatography and spectral analysis showed that the possible chemical structure consisted of →4)-α-Glcp-(1→ and a small quantity of →4,6)-β-Glcp-(1→ in the main chain and →6)-β-Glcp-(1→, α-Glcp-(1→, and β-Glcp-(1→ in the side chain. Morphological analysis using scanning electron microscopy (SEM) and atomic force microscopy (AFM) indicated that OFP had a multi-branched structure, and the sugar chain molecules of polysaccharide appeared aggregated. OFP was found to exhibit anti-inflammatory activity by reducing the secretion of inflammatory factors in RAW264.7 cells and by decreasing the extent of xylene-induced ear swelling in mice.

Effective strategies and tactics for teaching the Russian language to foreign military personnel in the conditions of digitalization of education

Актуальность статьи обусловлена необходимостью отбора и систематизации эффективных средств в обучении русскому языку как иностранному в условиях изменяющейся действительности, или глобальной цифровизации образовательного процесса. Исходя из этого цель статьи заключается в определении специфики создания электронных учебных материалов для эффективного преподавания русского как иностранного курсантам военно-инженерно-технического института военной академии материально технического обеспечения (далее - ВИТИ ВАМТО). Авторами сформулирован новый подход к организации электронных материалов или линейно-разветвлённый принцип обучения. Он наиболее эффективен при обучении иностранных курсантов, так как синтезирует в себе особенности уже классических принципов представления электронных упражнений в медиапространстве: линейного и разветвленного. В статье раскрыта сущность нового принципа обучения, линейно-разветвлённого, для всех видов речевой деятельности, которая заключается в том, что любая тема сопровождается как вопросами контролирующего характера, так и вопросами тестового характера, на основе чего прогнозируется дальнейшее цифровое обучение иностранных курсантов, а также прогнозируются наиболее эффективные способы и приёмы их обучения по концентрическому типу подачи материала. Классифицированы существующие электронные контенты, исходя из организации обучающей информации в них. Выделены два основных и предложен третий тип, синтезирующий в себе плюсы, имеющихся электронных обучающих упражнений и преодолевающий отрицательные стороны их. Предложено направить усилия на разработку упражнений линейно-разветвленной структуры для обучения русскому языку иностранных учащихся по всем видам речевой деятельности. Экспериментально констатирующим и контрольным срезом знаний иностранных курсантов доказано, что подача электронной информации по линейно- разветвленному принципу наиболее эффективна для преподавания русского как иностранного, так как преодолевает ряд отрицательных моментов при обучении русскому языку в цифровом или дистанционном формате. Доказано, что цифровое образование, построенное по принципу линейно-разветвлённого обучения, эффективно для тренировки грамматики и для повышения коммуникативной компетенции иностранных обучающихся при создании дополнительных фильмов не общеречевой тематики, а профессиональной направленности, необходимой им для овладения будущей профессией. Статья предназначена для преподавателей военных вузов, методистов и специалистов, разрабатывающих цифровой образовательный контент. The relevance of the article is due to the need to select and systematize effective means in teaching the Russian language as a foreign language in a changing reality, or the global digitalization of the educational process. Based on this, the purpose of the article is to determine the specifics of creating electronic educational materials for the effective teaching of Russian as a foreign student to the military engineering and technical institute of the military academy of logistics (hereinafter - VITI VAMTO). The authors formulated a new approach to the organization of electronic materials or a linearly branched principle of training. It is most effective in training foreign cadets, as it synthesizes the features of the already classical principles of presenting electronic exercises in media space: linear and branched. The article discloses the essence of the new principle of learning, linearly branched, for all types of speech activities, which consists in: that any topic is accompanied both by questions of a controlling nature and questions of a test nature, on the basis of which further digital training of foreign cadets is predicted, as well as the most effective methods and techniques for their training in a concentric type of material supply are predicted. Existing electronic content is classified based on the organization of training information in them. Two main ones are highlighted and a third type is proposed, synthesizing the pros, existing electronic training exercises and overcoming the negative sides of them. It is proposed to direct efforts to develop exercises of a linearly branched structure for teaching the Russian language to foreign students in all types of speech activities. An experimentally ascertaining and control section of the knowledge of foreign cadets proved that the submission of electronic information according to a linearly branched principle is most effective for teaching Russian as a foreign, as it overcomes a number of negates moments when learning Russian in digital or remote format. It has been proved that digital education, built on the principle of linear-branched learning, is effective for training grammar and for increasing the communicative competence of foreign students when creating additional films not of a general speech theme, but of the professional orientation necessary for them to master the future profession. The article is intended for teachers of military universities, methodologists and specialists developing digital educational content.

Novel reusable hydrogel adsorbents for precious metal recycle

A novel polyethylene glycol diacrylate-allylthiourea (ATU-PEGDA) hydrogel was simply synthesized through photo-reaction. Modified thiourea simultaneously employed chelation and electrostatic force to selectively recycle Ag(I) and Pd(II) from electrolytic wastewater. Sorption efficiency was nearly 100% for Ag(I) and Pd(II), which occurred at initial pH of 1 within 300 min. The adsorption characteristics of ATU-PEGDA followed Langmuir isotherm model and the maximum adsorption capacity of Ag(I) and Pd(II) achieved 83.33 and 152.81 mg g−1 sorbent, respectively where Pseudo-first order model demonstrate the adsorption kinetics. In the presence of other heavy metals, ATU-PEGDA performed high selectivity, 0.89 and 1.31 towards Ag(I) and Pd(II). ATU-PEGDA can be completely regenerated within 120 min using 0.5 M thiourea—0.001 M HNO3 and 1 M thiourea—4 M HCl after the adsorption of Ag(I) and Pd(II), respectively. Thiourea-branched structure was created after regeneration, improving the adsorption capacity. Compared to initial hydrogel, the adsorption capacity of Ag(I) and Pd(II) increased 31.83 ± 3.08% and 75.12 ± 11.02%, respectively. Over 10 consecutive adsorption–desorption cycles, ATU-PEGDA performed 111.34 and 263.79 mg g−1 sorbent in adsorption capacity of Ag(I) and Pd(II). Chromism of ATU-PEGDA hydrogel was a benefit to determine adsorption saturation and completely desorption of Ag(I) and Pd(II). Potentially, ATU-PEGDA can be extended to industrial applications.

The chemistry of branched condensed phosphates

Condensed phosphates may exist as linear, cyclic or branched structures. Due to their important role in nature, linear polyphosphates have been well studied. In contrast, branched phosphates (ultraphosphates) remain largely uncharacterised, because they were already described in 1950 as exceedingly unstable in the presence of water, epitomized in the antibranching-rule. This rule lacks experimental backup, since, to the best of our knowledge, no rational synthesis of defined ultraphosphates is known. Consequently, detailed studies of their chemical properties, reactivity and potential biological relevance remain elusive. Here, we introduce a general synthesis of monodisperse ultraphosphates. Hydrolysis half-lives up to days call the antibranching-rule into question. We provide evidence for the interaction of an enzyme with ultraphosphates and discover a rearrangement linearizing the branched structure. Moreover, ultraphosphate can phosphorylate nucleophiles such as amino acids and nucleosides with implications for prebiotic chemistry. Our results provide an entry point into the uncharted territory of branched condensed phosphates.

Anionic Copolymerization of Acrylonitrile with Ethyl Acrylate under the Action of the Initiating System of 1,4-Diazabicyclo[2.2.2]Octane – Ethylene Oxide

It was found, studying acrylonitrile copolymerization with ethyl acrylate in dimethyl sulfoxide under the action of anionic initiating system of 1,4-diazabicyclo [2.2.2] octane – ethylene oxide, that the obtained copolymers have a branched structure. An increase in the molar fraction of ethyl acrylate in the reaction medium leads to a decrease in the initial rate of acrylonitrile polymerization. Thermal behavior of copolymer samples was investigated; it was found that ethyl acrylate, being introduced into the polyacrylonitrile structure, both reduces thermal effects related to the reactions taking place during heat treatment of copolymers, and increases the half-width of the heat release peak.