Oil Phase Solubility Rather Than Diffusivity Determines the Release of Entrapped Amino Acids and Di-Peptides from Water-in-Oil-in-Water Emulsions

The permeation of amino acids and di-peptides with different hydrophobicities across the oil phase in W/O/W double emulsions was investigated at different concentrations, considering the pH of the aqueous phase. Moreover, the particle size, yield of entrapped water and release kinetics of the double emulsions was evaluated as a function of time. Regarding the release of the entrapped amino acids and di-peptides, their hydrophobicity and the pH had a significant effect, whereas the concentration of the dissolved compound did not lead to different release kinetics. The release of the amino acids and di-peptides was faster at neutral pH as compared to acidic pH values due to the increased solute solubility in the oil phase for more hydrophobic molecules at neutral pH. Regarding the effect of the type of oil, much faster amino acid transport was observed through MCT oil as compared to LCT oil, which might be due to its higher solubility and/or higher diffusivity. As di-peptides released faster than amino acids, it follows that the increased solubility overruled the effect from the decreased diffusion coefficient of the dissolved compound in the oil phase.

Non-alcoholic components of Pelinkovac, a Croatian wormwood-based strong liquor, counteract the inhibitory effect of high ethanol concentration on catalase in vitro

Antioxidant enzyme catalase protects the cells against alcohol-induced oxidative stress by scavenging free radicals and metabolizing alcohol. Concentrations of ethanol present in alcoholic beverages can inhibit catalase and foster oxidative stress and alcohol-induced injury. Non-alcoholic components of pelinkovac counteract the inhibitory effects of high ethanol concentration and acidic pH on catalase in vitro.

Electrochemical microelectrode degradation monitoring: in situ investigation of platinum corrosion at neutral pH

Objective. The stability of platinum and other noble metal electrodes is critical for neural implants, electrochemical sensors, and energy sources. Beyond the acidic or alkaline environment found in most electrochemical studies, the investigation of electrode corrosion in neutral pH and chloride containing electrolytes is essential, particularly regarding the long-term stability of neural interfaces, such as brain stimulation electrodes or cochlear implants. In addition, the increased use of microfabricated devices demands the investigation of thin-film electrode stability. Approach. We developed a procedure of electrochemical methods for continuous tracking of electrode degradation in situ over the complete life cycle of platinum thin-film microelectrodes in a unique combination with simultaneous chemical sensing. We used chronoamperometry and cyclic voltammetry to measure electrode surface and analyte redox processes, together with accelerated electrochemical degradation. Main results. We compared degradation between thin-film microelectrodes and bulk electrodes, neutral to acidic pH, different pulsing schemes, and the presence of the redox active species oxygen and hydrogen peroxide. Results were confirmed by mechanical profilometry and microscopy to determine material changes on a nanometer scale. We found that electrode degradation is mainly driven by repeated formation and removal of the platinum surface oxide, also within the electrochemical stability window of water. There was no considerable difference between thin-film micro- and macroscopic bulk electrodes or in the presence of reactive species, whereas acidic pH or extending the potential window led to increased degradation. Significance. Our results provide valuable fundamental information on platinum microelectrode degradation under conditions found in biomedical applications. For the first time, we deployed a unified method to report quantitative data on electrode degradation up to a defined endpoint. Our method is a widely applicable framework for comparative long-term studies of sensor and neural interface stability.

Formulation and evaluation of dexlansoprazole extended-release tablet

Dexlansoprazole (DSP) is a proton pump inhibitor, it used to treat GERD and ulcer colitis. DSP works by decreasing the volume of acid in the stomach. DSP is an acid-labile medication that may be destroyed in the stomach's acidic pH. A coating technique was used to postpone drug release in the stomach, which can extend pharmacological activity. Shellac can be used to develop the sustain release tablet of dexlansoprazole as retardation of the drug (dexlansoprazole) was observed in the acidic pH of the stomach, and hence a sustain coated dexlansoprazole tablet was prepared and evaluated. The coating's primary function is to allow for the delayed, immediate, and prolonged delayed release of DSP. DSP coating with different polymers inhibits faster degradation in the acidic pH of the stomach, therefore increasing pharmacological action. DSP coating with different polymers inhibits fast degradation in the stomach's acidic pH, enhancing pharmacological action. The major function of the coating is to enable for the delayed, immediate, and prolonged delayed release of DSP. DSP coating with different polymers inhibits fast breakdown in the stomach's acidic pH, enhancing pharmacological action.

Study of the surface properties of glauconite

The acid-base properties of the glauconite surface has been studied by potentiometric titration. Using a surface complexation model with a constant exchange capacity, it was shown that positively charged surface centers and exchange centers dominate in the acidic pH region, and negatively charged centers dominate in the neutral and alkaline regions. The corresponding constants of acid-base equilibrium have been calculated. The data obtained were used to study the sorption of cadmium and lead on glauconite.

Valorization of Olive Mill Wastewater in the Control of Aphis pomi De Geer 1773 (Hemiptera, Aphididae) Infesting Apple Plants in Nurseries

Olive mill wastewater (OMW), are the liquid residues generated during the extraction of oil by traditional and modern three-phase type crushing units. These effluents are characterized by an acidic pH and composition rich in water, organic matter, minerals and polyphenols. In general, they are directly discharged into natural ecosystems. Their danger is linked to the enormous quantities produced in a short period between October and March. To mitigate the effects of vegetable waters on the environment, their valorization in different areas is discussed. As biopesticides, crude OMW have been shown to be very toxic to Aphis pomi; the LC50 and LC95 varied respectively from 27.17 to 45.59 and from 77.19 to 134.57 mg of OMW/L of water; they vary according to the stage of the aphid considered. The young stages of A. pomi were more sensitive than the elderly are. Therefore, the OMW can be used as a means of controlling aphids. However, before operating on a large scale, it is necessary to repeat the trials in field and assess their impact on non-target organisms and treated crops.

The optimal pH of AID is skewed from that of its catalytic pocket by DNA-binding residues and surface charge

Activation-induced cytidine deaminase (AID) is a member of the apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like (APOBEC) family of cytidine deaminases. AID mutates immunoglobulin loci to initiate secondary antibody diversification. The APOBEC3 (A3) sub-branch mutates viral pathogens in the cytosol and acidic endosomal compartments. Accordingly, AID functions optimally near neutral pH, while most A3s are acid-adapted (optimal pH 5.5-6.5). To gain a structural understanding for this pH disparity, we constructed high-resolution maps of AID catalytic activity vs pH. We found AID’s optimal pH was 7.3 but it retained most (>70%) of the activity at pH 8. Probing of ssDNA-binding residues near the catalytic pocket, key for bending ssDNA into the pocket (e.g R25) yielded mutants with altered pH preference, corroborating previous findings that the equivalent residue in APOBEC3G (H216) underlies its acidic pH preference. AID from bony fish exhibited more basic optimal pH (pH 7.5-8.1) and several R25-equivalent mutants altered pH preference. Comparison of pH optima across the AID/APOBEC3 family revealed an inverse correlation between positive surface charge and overall catalysis. The paralogue with the most robust catalytic activity (APOBEC3A) has the lowest surface charge, most acidic pH preference, while the paralogue with the most lethargic catalytic rate (AID) has the most positive surface charge and highest optimal pH. We suggest one possible mechanism is through surface charge dictating an overall optimal pH that is different from the optimal pH of the catalytic pocket microenvironment. These findings illuminate an additional structural mechanism that regulates AID/APOBEC3 mutagenesis.