Ultrasonic Formation of Fe3O4‑Reduced Graphene Oxide−Salicylic Acid Nanoparticles with Switchable Antioxidant Function

We demonstrate a single-step ultrasonic in situ complexation of salicylic acid during the growth of Fe3O4-reduced graphene oxide nanoparticles (∼10 nm) to improve the antioxidant and antiproliferative effects of pristine drug molecules. These nanoparticles have a precisely defined electronic molecular structure with salicylic acid ligands specifically complexed to Fe(III)/Fe(II) sites, four orders of magnitude larger electric surface potential, and enzymatic activity modulated by ascorbic acid molecules. The diminishing efficiency of hydroxyl radicals by Fe3O4-rGO-SA nanoparticles is tenfold higher than that by pristine salicylic acid in the electro-Fenton process. The H+ production of these nanoparticles can be switched by the interaction with ascorbic acid ligands and cause the redox deactivation of iron or enhanced antioxidation, where rGO plays an important role in enhanced charge transfer catalysis. Fe3O4-rGO-SA nanoparticles are nontoxic to erythrocytes, i.e., human peripheral blood mononuclear cells, but surpassingly inhibit the growth of three cancer cell lines, HeLa, HepG2, and HT29, with respect to pristine salicylic acid molecules

Predictive analysis of two bijectively related families of functions in L

This article proposes a method of function image prediction calculation by its preimage. This method is based on regression analysis of function image and preimage pairs in L2. The prediction model application procedure is described. The algorithm pseudocod are given

Activation of ibuprofen via ultrasonic complexation with silver in N-doped oxidized graphene nanoparticles for microwave chemotherapy of cervix tumor tissue

An ultrasonic method (20 kHz) is introduced to activate pristine ibuprofen organic molecular crystals via complexation with silver in nitrogen-doped oxidized graphene nanoplatforms (∼50 nm). Ultra9 sonic complexation occurs in a single-step procedure through the binding of the carboxylic groups with Ag, H-bond formation, involving noncovalent πC=C → πC=C* transitions in the altered phenyl ring and πPY → πCO* in ibuprofen occurring between the phenyl ring and C−O bonds as a result of interaction with hydroxyl radicals. The ibuprofen−silver complex in ≪NrGO≫ exhibits a ∼42 times higher acceleration rate than free ibuprofen of the charge transfer between hexacyanoferrate and thiosulfate ions. The increased acceleration rate can be caused by electron injection/ejection at the interface of the ≪Ag-NrGO≫ nanoplatform and formation of intermediate species (Fe(CN)5(CNSO3)x− with x = 4 or 5 and AgHS2O3) at the excess of produced H+ ions. Important for microwave chemotherapy, ibuprofen−silver complexes in the ≪NrGO≫ nanoplatform can produce H+ ions at ∼12.5 times higher rate at the applied voltage range from 0.53 to 0.60 V. ≪Ibu-Ag-NrGO≫ NPs develop ∼105 order higher changes of the electric field strength intensity than free ibuprofen in the microwave absorption range of 100−1000 MHz as revealed from the theoretical modeling of a cervix tumor tissue

Investigation of discharge channel wall material influence on lifetime of hall effect thruster with high specific impulse

Results of 500-hour life tests of the 900-watt Hall-thruster laboratory model with the specific impulse of 2000 s are presented. The thruster discharge channel walls were manufactured from 60% BN + 40% SiO2 and >90% BN hot-pressed ceramics. The predicted total lifetime was ∼3000 h for both wall materials in spite of greater erosion resistance of pure BN in comparison with BN-SiO2 mixture. To clarify the accompanying phenomena, the following diagnostics were carried out. The surface microstructure and composition insulators were investigated by means of electron microscopy and X-ray fluorescence analysis and nearwall plasma parameters were measured with flat Langmuir probes. The obtained distributions of plasma parameters were compared with the results of stationary one-dimensional (1D) hydrodynamic modeling of discharge channel