Surface Functionalization of Poly(l-lactide-co-glycolide) Membranes with RGD-Grafted Poly(2-oxazoline) for Periodontal Tissue Engineering

Bone tissue defects resulting from periodontal disease are often treated using guided tissue regeneration (GTR). The barrier membranes utilized here should prevent soft tissue infiltration into the bony defect and simultaneously support bone regeneration. In this study, we designed a degradable poly(l-lactide-co-glycolide) (PLGA) membrane that was surface-modified with cell adhesive arginine-glycine-aspartic acid (RGD) motifs. For a novel method of membrane manufacture, the RGD motifs were coupled with the non-ionic amphiphilic polymer poly(2-oxazoline) (POx). The RGD-containing membranes were then prepared by solvent casting of PLGA, POx coupled with RGD (POx_RGD), and poly(ethylene glycol) (PEG) solution in methylene chloride (DCM), followed by DCM evaporation and PEG leaching. Successful coupling of RGD to POx was confirmed spectroscopically by Raman, Fourier transform infrared in attenuated reflection mode (FTIR-ATR), and X-ray photoelectron (XPS) spectroscopy, while successful immobilization of POx_RGD on the membrane surface was confirmed by XPS and FTIR-ATR. The resulting membranes had an asymmetric microstructure, as shown by scanning electron microscopy (SEM), where the glass-cured surface was more porous and had a higher surface area then the air-cured surface. The higher porosity should support bone tissue regeneration, while the air-cured side is more suited to preventing soft tissue infiltration. The behavior of osteoblast-like cells on PLGA membranes modified with POx_RGD was compared to cell behavior on PLGA foil, non-modified PLGA membranes, or PLGA membranes modified only with POx. For this, MG-63 cells were cultured for 4, 24, and 96 h on the membranes and analyzed by metabolic activity tests, live/dead staining, and fluorescent staining of actin fibers. The results showed bone cell adhesion, proliferation, and viability to be the highest on membranes modified with POx_RGD, making them possible candidates for GTR applications in periodontology and in bone tissue engineering.

Analysis of the Negative Impacts of Coffee Husk on the Local Environment

In a locality wherever intense low process is completed while not appropriate waste management measures, low effluents area unit the principal reason behind organic pollution. Low husk contains caffeine, tannins, and chlorogenic acid, creating it a dangerous exposed husk. The low method has been delivery environmental issues to the environment thanks to the discharge of pollution with a large quantity of organic waste. the target of this work is to research the negative impacts of low husk on the atmosphere to scale back environmental pollution in step with the planet Health Organization, one among the foremost vital problems that enterprises confront as they look for ways to limit their use of the artifact by changing it into value-add products/applications is that the harmful impact of low husk on the atmosphere (WHO).The significance of the experiment is to form low husk as an alternate resource to switch fiber. Methylene chloride liquid-liquid extraction was developed to avoid caffeine, tannin, and CGA spectral overlapping within the three hundred -700 nm wavelength vary. The results indicated increment deadly materials that have an effect on the atmosphere. From the experiment performed low husk are often used as an alternate resource for getting composites for might applications and solve the environmental issues.

Emission Characteristics and Ozone Formation Potential Assessment of VOCs from Typical Metal Packaging Plants

With the rapid development of metal packaging, volatile organic compounds (VOCs) emissions from the packaging processes are also increasing gradually. It is necessary to research the characteristics of VOCs emissions from such important industrial source and its impact on the possible ozone formation. In this research, three typical metal packaging plants were selected, VOCs emission characteristics were investigated, and their ozone formation potential were evaluated by using maximum incremental reactivity (MIR) coefficient method. The results showed that the VOCs emission characteristics of the selected targets were obviously different. VOCs emitted from plant A and B were mainly oxygenated hydrocarbons, which accounted for 85.02% and 43.17%, respectively. Olefins (62.75%) were the main species of plant C. 2-butanone (82.67%), methylene chloride (23.00%) and ethylene (36.67%) were the major species of plant A, plant B and plant C, respectively. The OFP (ozone formation potential) value of plant B (120.49 mg/m3) was much higher than those values of plant A (643.05 mg/m3) and plant C (3311.73 mg/m3), in which para-xylene, meta-xylene, acetaldehyde and ethylene were the main contributors. The difference in OFP values indicated that water-based ink and water-based coatings should be recommended for large scale application due to less VOCs emission and low ozone formation contribution.

Development of a mafedine lyophilizate for parenteral use

Introduction. Cerebrovascular disease (CVD) is the most important medical and social problem of modern neurology because they have the highest rates of morbidity, mortality and disablement in the population. The growing incidence of CVD as a result of an aging population worldwide requires the emergent development of therapeutics, diagnostic and preventive tools. However, the development of drugs for the treatment of brain diseases has limitations due to the presence of the blood-brain barrier, which protects the brain against most molecules from the bloodstream entering the central nervous system. At the St. Petersburg State Chemical Pharmaceutical University of the Ministry of Health of Russia the alpha-2 adrenergic agonist mafedine was synthesized, which has mild psychostimulant and anxiogenic effects and which may be used in the treatment of traumatic brain injury as a neuroprotective agent.Aim. The development of a dosage form of mafedine in order to improve its penetration into the central nervous system.Materials and methods. Mafedine (pharmaceutical substance) [6-oxo-1-phenyl-2-(phenylamino)-1,6-dihydropyrimidin-4-olate sodium] (St. Petersburg State Chemical-Pharmaceutical University of the Ministry of Health of Russia); lecithin, span-60, Tween-80, Poloxamer 188, mannitol, vitamin E, ascorbic acid, methylene chloride, dimethyl sulfoxide, acetonitrile, trifluoroacetic acid. The fine emulsion of mafedine was obtained by ultrasound. The dosage form of mafedine was obtained by freeze drying. Residual solvents were determined by gas chromatography. Quantitative analysis of mafedine was performed by high-performance liquid chromatography. Particle size and zeta potential of emulsion were determined on a Zetasizer Nano ZS.Results and discussion. Lyophilizate of mafedine was obtained and presenting as a light yellow porous, odorless tablet. The average mass of dry tablet was (0,17 ± 0,01) g with mafedine content is (26 ± 1) mg. The water content in the lyophilizate was 3,85 %. The quantity of methylene chloride in the lyophilizate correspond to the requirements for residual solvent content. The reconstitution time of lyophilizate into a primary emulsion was 3–5 seconds. The reconstituted dispersion was yellow, odorless, and did not break within 2 days during storage. The pH of the reconstituted emulsion was 7,34. The average particle size was (164,7 ± 6,4) nm, the zeta potential was –32 mV.Conclusion. The developed dosage form is stable according to its physicochemical and pharmaceutical characteristics and is suitable for experimental study on models as a neuroprotective and neurorehabilitation agent.

Flavonoids of the Heartwood of Cotinus coggygria Scop. Showing Protective Effect on Human Lymphocyte DNA

In continuation of our study on Cotinus coggygria from Serbia, 10 known flavonoids (1-10) were isolated from the methylene chloride/methanol extract of the heartwood. They were tested for in vitro protective effect against chromosome aberrations in peripheral human lymphocytes, using the cytokinesis-block micronucleus assay. All tested compounds (in minimal doses of 1 μg/mL) exerted a beneficial effect by decreasing DNA damage of human lymphocytes in the range of 24.2% to 54.5%, better than the radio protectant control, amifostine. Functional groups, such as 3′,4′-dihydroxyphenyl (catechol), 5-OH, 3-OH, and 4-keto in flavonoids (3-keto in aurones), which play a key role in antioxidant activity, are proposed to be responsible for the DNA protective activity of the tested compounds.

THE THERMODYNAMICS OF INTERACTIONS AND RELAXATION PROPERTIES OF THE POSS-CONTAINING NANOCOMPOSITES BASED ON POLYURETHANE-POLY(HYDROXYPROPYL METHACRYLATE) MATRIX, WHICH IS FORMED BY THE PRINCIPLE OF IPNS

A series of the nanocomposites based on a multicomponent polymer matrix consisting of polyurethane and poly(hydroxypropyl methacrylate) and 1,2-propanediolysobutyl polyhedral oligomeric silsesquioxane (1,2-propanediolysobutyl-POSS), used as a functionalized nanofiller, was synthesized. The polymer matrix was formed on the principle of interpenetrating polymer networks (IPNs). The influence of 1,2-propanediolysobutyl-POSS amount on the thermodynamics of polymer components of the matrix interactions and on the dynamic mechanical properties of the created nanocomposites was studied. With purpose of the thermodynamic parameters interactions calculations the isothermal sorption of methylene chloride vapour by samples was investigated. The methylene chloride vapour sorption by the samples was studied using a vacuum installation and a McBain balance. By calculations of the thermodynamic parameters of PU and PHPMA interactions was shown that the free energy of PU and PHPMA mixing was positive. The introduction of 1-3 wt % of POSS lead to further phase separation in semi-IPNs. This is due to concentration of POSS particles in the PU’s nanodomains. The increasing of POSS content up to 5-10 wt % lead to compatibi-lization in semi-IPNs. These is due to concentration of POSS nanoparticles not only in the PU’s nanodomains but also in the interphase region of semi-IPN. The dynamic mechanical properties of the created nanocomposites were investigated and the degree of polymer components segregation was calculated. It was shown that there are two peaks of tan δ (PU and PHPMA) in the nanocom-posites. The introduction of 1-3 wt % of POSS lead to increasing of tan δ peak of PHPMA and to deepening of the bridge between two peaks (PU and PHPMA). At the same time the degree of polymer components of the matrix segregation became higher. This means the further phase separation in semi-IPNs. Increasing of 1,2-propanediolysobutyl-POSS amount up to 5-10% leads to the concentration of the nanofiller not only in the nanodomains of PU, but also in the interfacial layers. This leads to a change in the free energy of polymer components mixing, which becomes negative. At the same time the degree of polymer components of the matrix segregation became significantly reduced. These means that the process of compatibilization took part in the semi-IPNs.

Effects of Plastic Pollution of Soil on the Growth and Survival of Bacteria and Fungi

The study examined the effect of plastic waste on soil bacteria and fungi. The test soil samples were collected from Lokoja international market waste dump site and the control soil sample was collected from non plastic contaminated garden in Salem University, Lokoja. The samples were analysed using Gas chromatography with mass spectrometer. The test soil sample soil sample had high quantity of plastic contaminant which were Methylene chloride 17.45mg/kg, hexane 10.05mg/kg, chloroform 1.56mg/kg, toluene 5.87mg/kg, tetrachloroethylene 1.48mg/kg as compared to the control garden soil sample, which had methylene chloride 0.54mg/kg, hexane 0.26mg/kg, chloroform 0.31mg/kg, toluene 5.87mg/kg and tetrachloroethylene 0.01mg/kg. The result showed the presence of plastic in the soil and it effect on bacteria and fungi. The totals of 11 bacteria were isolated from both soil samples using nutrient agar. The bacteria isolated are; Corynebacterium spp. (12%), Enterobacter spp. (8%), Acinetobacter spp. (6%), Escherichia coli (16%), Epidermis, Bacillus subtilis (15%), Serratia sp. (8%), Proteus spp. (4%), Micrococcus luteus (7%), Flavobacterium spp. (10%), Pseudomonas aeruginosa (15%). Micrococcus luteus, Flavobacterium spp. and Pseudomonas aeruginose were not isolated in plastic composted soil sample due to the presence of plasticizers. The total of 6 fungi were isolated, namely Penicilliun expansion (12%), Sacchromyces sp. (24%), Aspergillus niger (19%), Fusarium spp. (20%), Rhizopus stolonifer (10%) and Mucor piriformis (15%). This study reveals the effect of plastic waste, as it inhibits the growth of microorganism that is important for soil activities, thereby reducing the soil nutrients, fertility and productivity.

Chromatography-mass spectrometric determination of highly toxic and carcinogenic N-nitrosamines in water

Introduction. In Russia, the current condition regarding water quality in the water bodies of the Russian Federation used for drinking purposes “continues to remain unfavourable (according to the Strategy of the Environmental Safety of the Russian Federation until 2025). It takes place primarily due to the discharges of industrial and domestic wastewater.” Thus, 19% of wastewater is discharged into water bodies without purification, 70% - insufficiently purified, and only 11% - purified to the established acceptable discharge standards. Therefore, 30-40% of the country’s population regularly uses water that does not correspond to the hygienic standards, which leads to an increased risk of morbidity among the population of Russia. This study aims to execute chromatography-mass spectrometric determination of highly toxic and carcinogenic N-nitrosamines in drinking water. Materials and methods. Within the framework of the study, we reviewed standard samples of N-nitrosamines Mix, 1X1ML, 2000 ug/ml, methanol, experimental diagrams of solid-phase extraction. The practical charts of solid-phase extraction were tested with the help of a susceptible and accurate analytical mass-spectrometric method, a gas chromatograph with a mass selective detector (MSD). An internal laboratory control was carried out according to CIS standardization recommendations 76-2014 of the State System for Ensuring Uniform Measurement to ensure the reliability of the analytical results obtained to determine N-nitrosamines in water. The quality indicators for the analysis results were experimentally established: the accuracy, correctness, precision of the analysis technique, and the methods for their assessment according to GOST R ISO 5725-2002 standards. Results. In the course of the performed experimental studies, it was found that the degree of N-nitrosamines extraction from water samples of 100 ml volume, through scavenging analytes on a carbon cartridge (Coconut 6 cm3) and using four optimal diagrams of solid-phase extraction - SPE for N-dimethyl nitrosamine, N-diethyl nitrosamine, N-dipropyl nitrosamine, N-piperidine nitrosamine was 73.9%, 90.8%, 100 and 95.4% respectively. Optimal elution scheme 4: stage 1 - conditioning the cartridge to activate it: 5 ml methylene chloride for 3 seconds, 5 ml ethyl acetate for 3 seconds, rinsing the cartridge with 5 ml water for 10 seconds. Stage 2 - adsorption of a 100 ml water sample on a 6 ml Coconut cartridge for 1 minute; stage 3 - rinsing the cartridge with 5% sodium chloride solution of 10 ml for 30 seconds; stage 4-elution of N-nitrosamines from the cartridge with methylene chloride of 3 ml for 3 min. into a test tube in position 1 of the carriage of the automatic TFE system. The method for the determination of N-nitrosamines in water is based on the concentration of the analyzed compounds of water samples on a carbon cartridge - solid-phase extraction (SPE), identification of substances by library mass spectra and retention time, quantitative determination according to the calibration graph on a high polarity capillary column HP-FFAP-50 m • 0.32 mm • 0.50 μm. Conclusion. The developed guidelines for measuring the N-nitrosamines content in the water of centralized water supply systems let us determine highly toxic compounds at the lower limit of 0.00004 μg/cm3 with an error of more than 35.0%.

Liver dysfunctions in workers with methylene chloride and methanol in connection with sanitary and hygienic examination of their working conditions

During the production of the base of the triacetate (non-combustible) film, vapors of methylene chloride, methanol, acetone are in the working room. In connection with the examination of the workers of this production, the state of the air environment in all the main departments of the workshop was also studied. The influence of individual operations on air pollution was revealed.