Thermodynamic Studies of Interactions between Sertraline Hydrochloride and Randomly Methylated β-Cyclodextrin Molecules Supported by Circular Dichroism Spectroscopy and Molecular Docking Results

The interaction between sertraline hydrochloride (SRT) and randomly methylated β-cyclodextrin (RMβCD) molecules have been investigated at 298.15 K under atmospheric pressure. The method used—Isothermal Titration Calorimetry (ITC) enabled to determine values of the thermodynamic functions like the enthalpy (ΔH), the entropy (ΔS) and the Gibbs free energy (ΔG) of binding for the examined system. Moreover, the stoichiometry coefficient of binding (n) and binding/association constant (K) value have been calculated from the experimental results. The obtained outcome was compared with the data from the literature for other non-ionic βCD derivatives interacting with SRT and the enthalpy-entropy compensation were observed and interpreted. Furthermore, the connection of RMβCD with SRT was characterized by circular dichroism spectroscopy (CD) and complexes of βCD derivatives with SRT were characterized through the computational studies with the use of molecular docking (MD).     

Silver Nanoparticles Impair Cognitive Functions and Modify the Hippocampal Level of Neurotransmitters in a Coating-Dependent Manner

Due to their potent antibacterial properties, silver nanoparticles (AgNPs) are widely used in industry and medicine. However, they can cross the brain–blood barrier, posing a risk to the brain and its functions. In our previous study, we demonstrated that oral administration of bovine serum albumin (BSA)-coated AgNPs caused an impairment in spatial memory in a dose-independent manner. In this study, we evaluated the effects of AgNPs coating material on cognition, spatial memory functioning, and neurotransmitter levels in rat hippocampus. AgNPs coated with BSA (AgNPs(BSA)), polyethylene glycol (AgNPs(PEG)), or citrate (AgNPs(Cit)) or silver ions (Ag⁺) were orally administered at a dose of 0.5 mg/kg b.w. to male Wistar rats for a period of 28 days, while the control (Ctrl) rats received 0.2 mL of water. The acquisition and maintenance of spatial memory related to place avoidance were assessed using the active allothetic place avoidance task, in which rats from AgNPs(BSA), AgNPs(PEG), and Ag⁺ groups performed worse than the Ctrl rats. In the retrieval test assessing long-term memory, only rats from AgNPs(Cit) and Ctrl groups showed memory maintenance. The analysis of neurotransmitter levels indicated that the ratio between serotonin and dopamine concentration was disturbed in the AgNPs(BSA) rats. Furthermore, treatment with AgNPs or Ag⁺ resulted in the induction of peripheral inflammation, which was reflected by the alterations in the levels of serum inflammatory mediators. In conclusion, depending on the coating material used for their stabilization, AgNPs induced changes in memory functioning and concentration of neurotransmitters.     

The WindSat spaceborne polarimetric microwave radiometer: sensor description and early orbit performance

The global ocean surface wind vector is a key parameter for short-term weather forecasting, the issuing of timely weather warnings, and the gathering of general climatological data. In addition, it affects a broad range of naval missions, including strategic ship movement and positioning, aircraft carrier operations, aircraft deployment, effective weapons use, underway replenishment, and littoral operations. WindSat is a satellite-based multifrequency polarimetric microwave radiometer developed by the Naval Research Laboratory for the U.S. Navy and the National Polar-orbiting Operational Environmental Satellite System Integrated Program Office. It is designed to demonstrate the capability of polarimetric microwave radiometry to measure the ocean surface wind vector from space. The sensor provides risk reduction for the development of the Conical Microwave Imager Sounder, which is planned to provide wind vector data operationally starting in 2010. WindSat is the primary payload on the Department of Defense Coriolis satellite, which was launched on January 6, 2003. It is in an 840-km circular sun-synchronous orbit. The WindSat payload is performing well and is currently undergoing rigorous calibration and validation to verify mission success.     

The analysis of pneumatic atomization of Newtonian and non-Newtonian fluids for different medical nebulizers

Objective: The article contains results of the experimental studies on atomization process of inhaled drugs and aqueous solutions of glycerol with aqueous solutions of glycerol polyacrylamide (Rokrysol WF1) in pneumatic nebulizers. In experiments, the different concentration of aqueous solutions of glycerol polyacrylamide have been tested. In addition, the effect of nebulizer design on atomization process has been determined. The one of the main elements of medical pneumatic nebulizer is nebulizer cup.

Significance: The experiment with this scope is new and is very important from the point of view of aerosol therapy.

Methods: The results have been obtained by the use of the digital microphotography technique. In order to determine a physicochemical properties of tested liquids, a rheological measurements and measurements of the surface tension were carried out.

Results: The differences between characteristics of aerosol for the liquids have been observed. The analysis of the droplets size distributions shows that the different diameters of droplets for Newtonian and non-Newtonian fluids have been formed during atomization in pneumatic nebulizers equipped with different nebulizer cups. The effect of the mouthpiece location on the droplets diameters has been shown.

Conclusions: Precise design of nebulizer and nebulizer cups, and also physicochemical properties of atomized liquids are of high importance in order to the effectiveness of drug delivery to patient’s respiratory tracts.     

Development of a Method Based on Natural Deep Eutectic Solvents for Extraction of Flavonoids from Food Samples

Natural deep eutectic solvents (NADES) are promising green solvents for the extraction of compounds from natural products. This is the first study to use a sample preparation method based on NADES for the extraction of flavonoids (rutin, hesperidin, neohesperidin, naringenin, naringin, quercetin, hesperetin, and chrysin) from fruits, vegetables, and spices. In total, 17 types of NADES based on choline chloride, acetylcholine chloride, choline tartrate, betaine, and carnitine with different compositions were tailored to test their extraction efficiency. Operational conditions such as water content in NADES and liquid/solid ratios were also studied. A response surface methodology was used for multivariate optimization of some extraction parameters. Efficient recovery of extracted flavonoids (higher than 70%) was achieved using a 30% water solution of acetylcholine chloride/lactic acid ratio (2:1) as an extraction solvent. Other conditions for SLE-NADES were as follows: liquid/solid ratio 3:1, extraction temperature 60 °C, extraction time 30 min, and stirring speed 1400 rpm. Each extract was analyzed by UHPLC with UV and MS/MS detection. The developed method was applied for analysis of flavonoids in fruits (cranberry, fruits of Lycium barbarum L., grape, plum, and orange peel), vegetables (onion and broccoli), and spices (mustard, rosemary, and black pepper).     

Quality assessment of ZnO-based varistors by 1/f noise

Noise has been used as a diagnostic tool of surge arrester varistor structures comprising of ZnO grains of various type and size. The physical and electrical properties of the measured samples have been described. In the experimental study, the applied measurement system and the results of noise measurements for the selected structures of varistors designed for the continuous working voltage 280 V, 440 V and 660 V have been presented. Noise properties are related to electrical characteristics of the measured specimens giving more distinctive results than their voltage–current characteristics. It is suggested that the proposed procedure can be applied as an effective non-destructive testing method focused on defects and structural heterogeneity detection in the tested objects to assess their preparation processes.     

Multiplexed lipid dip-pen nanolithography on subcellular scales for the templating of functional proteins and cell culture

Molecular patterning processes taking place in biological systems are challenging to study in vivo because of their dynamic behavior, subcellular size, and high degree of complexity. In vitro patterning of biomolecules using nanolithography allows simplification of the processes and detailed study of the dynamic interactions. Parallel dip-pen nanolithography (DPN) is uniquely capable of integrating functional biomolecules on subcellular length scales due to its constructive nature, high resolution, and high throughput. Phospholipids are particularly well suited as inks for DPN since a variety of different functional lipids can be readily patterned in parallel. Here DPN is used to spatially pattern multicomponent micro- and nanostructured supported lipid membranes and multilayers that are fluid and contain various amounts of biotin and/or nitrilotriacetic acid functional groups. The patterns are characterized by fluorescence microscopy and photoemission electron microscopy. Selective adsorption of functionalized or recombinant proteins based on streptavidin or histidine-tag coupling enables the semisynthetic fabrication of model peripheral membrane bound proteins. The biomimetic membrane patterns formed in this way are then used as substrates for cell culture, as demonstrated by the selective adhesion and activation of T-cells.     

Studies of the Kinetics of Lithium Grease Microstructure Regeneration by Means of Dynamic Oscillatory Rheological Tests and FTIR–ATR Spectroscopy

As part of this research, the kinetics of soap grease thickener microstructure regeneration during 24-h relaxation after 1-h shearing were studied. A lubricating grease, based on mineral oil ORLEN OIL SN-400, containing associated molecules of lithium 12-hydroxystearate was subjected to analysis. Rheological dynamic oscillatory and FTIR–ATR (Fourier Transform Infrared Attenuated Total Reflectance) spectroscopy were used to study the kinetics of thickener microstructure regeneration. Changes in the values of storage modulus G′ and loss modulus G″ of the investigated grease during its relaxation in the linear viscoelastic range were examined. In addition, the mechanical stability of the thickener microstructure at a variable oscillation frequency was tested, and changes in the cohesive energy of the grease versus the latter’s relaxation time were assessed. FTIR–ATR spectroscopy was used to study the physicochemical interactions between the associated molecules of lithium 12-hydroxystearate. Infrared bands were assigned to the vibrations of the particular functional groups of the grease components, and the spectral parameters in the absorption spectra in the range of 700–3,700 cm^?1 were examined. The studies carried out using the two investigative methods have revealed that the intensity of thickener microstructure regeneration was the highest in the first hour of grease relaxation after shearing. In this time interval, the largest changes in the vibrations of the main functional groups of the grease components were observed. In the next hours, the kinetics of thickener microstructure regeneration were substantially lower.     

Synthesis of solid epoxy resins base on BPC II and bisphenol A using conventional heating equipment and microwave

New solid state epoxy resins based on diglycidyl ether of 1,1‐dichloro‐2,2 bis (4‐hydroxyphenyl), ethylene (BPC) and BPA epoxy resins in the reaction with BPC and BPA were developed. Solid epoxy resins were synthesised by the use of two different heating methods: conventional and microwave reactor. The use of microwave radiation as novel heating medium as an alternative to the conventional methods, which provide a quicker and more effective synthesis. The solid epoxies have high melting points higher than 100°C and the polycondensation degree remains between n = 4–12. Epoxy value stays low and occurs around 0,02–0,1. BPA epoxy resins and diglycidylether of BPC II were compared in terms of reaction speed. It can be seen that the reaction of BPC diglycidylether occurs approximately 20% quicker given the same reaction conditions of temperature, and balance of catalyst. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3850–3854, 2006