Search Results (10)

The article reports on the development of a fundamentally new, effective technology for recycling waste tires using the explosive-circulation technology method, which was implemented in industry at a working factory. The construction of an explosion-circulation reactor, in which tires are destroyed under the influence of an explosion, is described. The main technological stages of the reactor operation include the formation of a tire package with a height of about 2.4 m and a mass of up to 1000 kg; cooling the package by air turbo-cooling machine to a temperature of minus 70–80 °C; placing the package into the reactor; initiating the explosive charge; and removing the tire shedding products with a subsequent granulometric classification of the resulting rubber crumb. The resulting rubber crumb has good wettability, which eliminates the need for an additional technological stage of activating the crumb surface. This made it possible to successfully use the obtained rubber crumb to improve the characteristics of road construction bitumen, the hardness of which at −16 °C decreased from 217 to 161 MPa. Using atomic force microscopy (AFM), gas chromatography, mass spectrometry, GPC, and XPS, it was established that the good wettability of the crumbs is explained by the formation of molecules with polar groups (C-O, C=O, C(O)O, C-S, C-SO_x, Zn-S, O-Si(O)-O) on the crumb surface as a result of the explosion. Full article

Core–shell inorganic/organic composites have often been applied as fillers in electromagnetic interference shielding. Those composed of conducting polymers and ferrites are of particular interests with respect to their electrical and magnetic properties. Pyrrole was oxidized in aqueous medium in the presence of manganese-zinc ferrite microparticles with ammonium peroxydisulfate or iron(III) chloride to yield polypyrrole-coated, core–shell microstructures. The effect of methyl orange dye on the conversion of globular polypyrrole to nanotubes has been demonstrated by electron microscopy when iron(III) chloride was used as an oxidant. The formation of polypyrrole was proved by FTIR spectroscopy. The completeness of ferrite coating was confirmed by Raman spectroscopy. The resistivity of composite powders was determined by four-point van der Pauw method as a function of pressure applied up to 10 MPa. The conductivity of composite powders was determined by a polypyrrole matrix and only moderately decreased with increasing content of ferrite. The highest conductivity of composites, 13–25 S cm⁻¹, was achieved after the deposition of polypyrrole nanotubes. Magnetic properties of composites have not been affected by the polypyrrole moiety, and the magnetization of composites was proportional to the ferrite content. Full article

Oral and parenteral delivery routes of valproic acid (VA) are associated with serious adverse effects, high hepatic metabolism, high clearance, and low bioavailability in the brain. A GastroPlus program was used to predict in vivo performance of immediate (IR) and sustained release (SR) products in humans. HSPiP software 5.4.08 predicted excipients with maximum possible miscibility of the drug. Based on the GastroPlus and HSPiP program, various excipients were screened for experimental solubility, nanoemulsions, and respective gel studies intended for nasal-to-brain delivery. These were characterized by size, size distribution, polydispersity index, zeta potential, morphology, pH, % transmittance, drug content, and viscosity. In vitro drug release, ex vivo permeation profile (goat nasal mucosa), and penetration studies were conducted. Results showed that in vivo oral drug dissolution and absorption were predicted as 98.6 mg and 18.8 mg, respectively, from both tablets (IR and SR) at 8 h using GastroPlus. The predicted drug access to the portal vein was substantially higher in IR (115 mg) compared to SR (82.6 mg). The plasma drug concentration–time profile predicted was in good agreement with published reports. The program predicted duodenum and jejunum as the prime sites of the drug absorption and no effect of nanonization on T_max for sustained release formulation. Hansen parameters suggested a suitable selection of excipients. The program recommended nasal-to-brain delivery of the drug using a cationic mucoadhesive nanoemulsion. The optimized CVE6 was associated with the optimal size (113 nm), low PDI (polydispersity index) (0.26), high zeta potential (+34.7 mV), high transmittance (97.8%), and high strength (0.7% w/w). In vitro release and ex vivo permeation of CVE6 were found to be substantially high as compared to anionic AVE6 and respective gels. A penetration study using confocal laser scanning microscopy (CLSM) executed high fluorescence intensity with CVE6 and CVE6-gel as compared to suspension and ANE6. This might be attributed to the electrostatic interaction existing between the mucosal membrane and nanoglobules. Thus, cationic nanoemulsions and respective mucoadhesive gels are promising strategies for the delivery of VA to the brain through intransal administration for the treatment of seizures and convulsions. Full article

The most concerning adverse effects of thrombolytic agents are major bleeding and intracranial hemorrhage due to their short half-life, low fibrin specificity, and high dosage. To alleviate bleeding side effects during thrombolytic therapy which would bring about the risk of aggravation, we try to find a novel biodegradable delivery nanosystem to carry drugs to target the thrombus, reduce the dosage of the drug, and system side effects. A novel urokinase/poly-α, β-d, l-aspartyl-Arg-Gly-Asp-Ser complex (UK/PD-RGDS) was synthesized and simply prepared. Its thrombolytic potency was assayed by the bubble-rising method and in vitro thrombolytic activity by the thrombus clot lysis assay separately. The in vivo thrombolytic activity and bleeding complication were evaluated by a rat model of carotid arteriovenous bypass thrombolysis. The thrombolytic potency (1288.19 ± 155.20 U/mg) of the UK/PD-RGDS complex nano-globule (18–130 nm) was 1.3 times that of commercial UK (966.77 ± 148.08 U/mg). In vivo, the UK/PD-RGDS complex (2000 IU/kg) could reduce the dose of UK by 90% while achieving the equivalent thrombolysis effect as the free UK (20,000 IU/kg). Additionally, the UK/PD-RGDS complex decreased the tail bleeding time compared with UK. The organ distribution of the FITC-UK/PD-RGDS complex was explored in the rat model. The UK/PD-RGDS complex could provide a promising platform to enhance thrombolytic efficacy significantly and reduce the major bleeding degree. Full article

Multiple daily injections via subcutaneous route are the primary modes of insulin delivery for patients with Diabetes Mellitus. While this process is invasive, painful and may cause patients to develop lipohypertrophy at injection site, the perception of fear surrounding this process causes patients to delay in initiation and remain persistent with insulin therapy over time. Moreover, poor glycemic control may often lead to acute complications, such as severe hypoglycemia and nocturnal hypoglycemia, especially in older patients with diabetes. To address the imperative need for a patient-convenient non-invasive insulin therapy, an insulin-loaded arginine-coated self-emulsifying nanoglobule system (INS-LANano) was developed for nasal delivery of insulin with a biodegradable cationic surfactant—Lauroyl Ethyl Arginate (LAE). Incorporation of LAE resulted in formation of positively charged nanoglobules with L-arginine oriented on the surface. LANano enabled binding of insulin molecules on the surface of nanoglobules via an electrostatic interaction between negatively charged α-helix and LAE molecules at physiological pH. INS-LANano showed a hydrodynamic diameter of 23.38 nm with a surface charge of +0.118 mV. The binding efficiency of insulin on LANano globules was confirmed by zeta potential, circular dichroism (CD) spectroscopy and centrifugal ultrafiltration studies. The attachment of insulin with permeation-enhancing nanoglobules demonstrated significantly higher in vitro permeability of insulin of 15.2% compared to insulin solution across human airway epithelial cell (Calu-3) monolayer. Upon intranasal administration of INS-LANano to diabetic rats at 2 IU/kg insulin dose, a rapid absorption of insulin with significantly higher Cmax of 14.3 mU/L and relative bioavailability (BA) of 23.3% was observed. Therefore, the INS-LANano formulation significant translational potential for intranasal delivery of insulin Full article

The rubber crumbs produced by the explosive circular destruction of worn-out automobile tires were studied. The crumbs showed high hydrophilicity. Their surface was analyzed by X-ray photoelectron spectroscopy. C, O, S, Zn, and Si were detected on the surface, and their chemical states were determined. The same chemical composition in the rubber crumb surface prepared by the explosive grinding of tires, as well as nanoglobules covering the crumb surface, was revealed. The appearance of polar groups on the crumb surface explains its high hydrophilicity and good compatibility with polymer matrices. Full article

Porous carbon–carbon composite materials (PCCCM) were synthesized by the alkaline dehydrochlorination of polyvinyl chloride solutions in dimethyl sulfoxide containing the modifying additives of a nanostructured component (NC): graphite oxide (GO), reduced graphite oxide (RGO) or nanoglobular carbon (NGC), with subsequent two-step thermal treatment of the obtained polyvinylene–NC composites (carbonization at 400 °C and carbon dioxide activation at 900 °C). The focus of the study was on the analysis and digital processing of transmission electron microscopy images to study local areas of carbon composite materials, as well as to determine the distances between graphene layers. TEM and low-temperature nitrogen adsorption studies revealed that the structure of the synthesized PCCCM can be considered as a porous carbon matrix in which either carbon nanoglobules (in the case of NGC) or carbon particles with the “crumpled sheet” morphology (in the case of GO or RGO used as the modifying additives) are distributed. Depending on the features of the introduced 5–7 wt.% nanostructured component, the fraction of mesopores was shown to vary from 11% to 46%, and S_BET—from 791 to 1115 m² g⁻¹. The synthesis of PCCNC using graphite oxide and reduced graphite oxide as the modifying additives can be considered as a method for synthesizing a porous carbon material with the hierarchical structure containing both the micro- and meso/macropores. Such materials are widely applied and can serve as adsorbents, catalyst supports, elements of power storage systems, etc. Full article

Introduction: Luteolin (LUT) is natural flavonoid with multiple therapeutic potentials and is explored for transdermal delivery using a nanocarrier system. LUT loaded cationic nanoemulsions (CNE1–CNE9) using bergamot oil (BO) were developed, optimized, and characterized in terms of in vitro and ex vivo parameters for improved permeation. Materials and methods: The solubility study of LUT was carried out in selected excipients, namely BO, cremophor EL (CEL as surfactant), labrasol (LAB), and oleylamine (OA as cationic charge inducer). Formulations were characterized with globular size, polydispersity index (PDI), zeta potential, pH, and thermodynamic stability studies. The optimized formulation (CNE4) was selected for comparative investigations (% transmittance as %T, morphology, chemical compatibility, drug content, in vitro % drug release, ex vivo skin permeation, and drug deposition, DD) against ANE4 (anionic nanoemulsion for comparison) and drug suspension (DS). Results: Formulations such as CNE1–CNE9 and ANE4 (except CNE6 and CNE8) were found to be stable. The optimized CNE4 based on the lowest value of globular size (112 nm), minimum PDI (0.15), and optimum zeta potential (+26 mV) was selected for comparative assessment against ANE4 and DS. The %T values of CNE1–CNE9 were found to be ˃95% and CEL content slightly improved the %T value. The spherical CNE4 was compatible with excipients and showed % total drug content in the range of 97.9–99.7%. In vitro drug release values from CNE4 and ANE4 were significantly higher than DS. Moreover, permeation flux (138.82 ± 8.4 µg/cm²·h), enhancement ratio (8.23), and DD (10.98%) were remarkably higher than DS. Thus, ex vivo parameters were relatively high as compared to DS which may be attributed to nanonization, surfactant-mediated reversible changes in skin lipid matrix, and electrostatic interaction of nanoglobules with the cellular surface. Conclusion: Transdermal delivery of LUT can be a suitable alternative to oral drug delivery for augmented skin permeation and drug deposition. Full article

Curcumin nanoemulsion was prepared using coconut oil, Tween 80 (surfactant) and polyethylene glycol (co-solvent) with the addition of honey and glycerol as additives. The nanoemulsion was optimized and systematically characterized for transdermal delivery. Small particle size (15.92 nm), low polydispersity index (0.17) and slight acidic (pH 4.18) curcumin nanoemulsion was obtained without any chemical degradation based on the Fourier transform infrared (FTIR) spectrum. The incorporation of curcumin inside nanoglobul improved curcumin stability and skin permeability. Its high permeability can be seen from Nile dyed curcumin in different layers of skin through fluorescent imaging. The release kinetic of curcumin followed the Higuchi model, which explains why the skin permeation was a Fickian diffusion-controlled process because the Korsmeyer constant was proven to be 0.3 (<0.5). Nanoencapsulation slightly decreased the antioxidant capacity of curcumin for about 7.9% compared to its free counterpart. It showed low cytotoxicity (EC₅₀ 2.3552 µg/mL) to human skin fibroblasts. Cell death was noticed at a high concentration (2.5 µg/mL) of treatment. Curcumin was also found to promote wound closure at low concentration 0.1563 µg/mL and was comparable with the performance of ascorbic acid based on scratch assay. Therefore, this nutritious curcumin nanoemulsion is a promising transdermal delivery system for topical application. Full article

The present study demonstrated formation of Ca and P rich nanoglobules by a mixed natural halophilic population enriched from hypersaline lake sediments in laboratory culture experiments. Nanoglobules consisting of complex mixture of Ca, P, O, and C with minor amount of Mg occurred in the external envelop of bacterial cell in the first week of incubation at various Mg⁺²/Ca⁺² ratios and salinity at 30 °C. Unlike the control experiments (e.g., non-viable cells and without cells), later aggregation and transformation of nanoglobules caused the precipitation of calcium and/or magnesium carbonates in variable amount depending on the Mg⁺²/Ca⁺² ratios of the medium after 37 days of incubation. By showing the nucleation of carbonates on bacterial nanoglobules closely associated with the cell surfaces of mixed natural population this study emphasis that formation of nanoglobules may not be specific to a microbial strain or to activity of a particular microbial group. Formation of carbonate nanoglobules under various conditions (e.g., Mg⁺²/Ca⁺² ratios, salinity) with the same halophilic culture suggest that the although metabolic activity of bacteria have an influence on formation of nanoglobules the mineralogy of nanoglobules may be controlled by the physicochemical conditions of the precipitation solution and the rate of mineral precipitation. Full article