Enthalpies of sublimation and vaporization of poly-substituted phenols containing intramolecular hydrogen bonds by solution calorimetry method

© 2020 Elsevier B.V. A simple procedure for calculation of solvation enthalpy of compounds containing intramolecular hydrogen bond was developed. This procedure is based on the assumption that fragments of molecules containing intramolecular hydrogen bonds can be express as one group contribution. The proposed approach was verified by determination of the vaporization/sublimation enthalpies of poly-substituted phenols. Vaporization/sublimation enthalpies were obtained as difference between solution and solvation enthalpies in benzene. Solution enthalpies of thirteen compounds in benzene were measured in the present study. The obtained vaporization/sublimation enthalpies are in good agreement with values available in the literature. This promising result makes the solution calorimetry method preferable for quick estimations of enthalpy of phase transition, especially for explosive or compounds of low volatility

Variability of morphophysiological parameters of Chenopodium album and Taraxacum officinale in the conditions of Kazan

One of the promising methods for the integral assessment of the quality of the environment and the vital activity of herbaceous plants is the assessment of the state of living organisms by the morphometric characters development stability. The study revealed an increase in the variability of morphological characters in the plants of lamb's quarters (Chenopodium album) and milk-witch gowan (Taraxacum officinalis) in areas with a high level of technogenic pollution. Phenotypes with smaller sizes of vegetative organs prevailed there, as compared with the area with a low level of pollution. At the same time, viable seeds and seedlings were formed in the plants of urban cenoses

Zoning of the urban environment by the level of soil pollution and its impact on the formation of risks to public health

© 2020, Editorial board of Journal of Experimental Biology and Agricultural Sciences. All rights reserved. The priority pollutants of urban soils are oil products, nitrates, cadmium, and zinc. The total non-carcinogenic risk was higher in the Kirovsky and Vakhitovsky districts of the city, and the dermal path was the most significant among the chemical penetration pathways. The distribution of risk factors for adolescent health along the path of inhalation was determined for the various critical target organs such as kidneys, hormones, blood, and respiratory systems. Analysis of the content of total metals in the soils of different districts showed that copper, zinc, lead made the major contribution to pollution in the calculation according to MAC (Zc) in all districts. Nitrates remain an important contaminant in every city under study. The values of total pollution factor, both for total and mobile forms of metals, did not exceed 16 units allowing placing the samples under study into a category with allowable contamination. The content of mobile forms of metals (apart from cadmium) did not exceed regulations in all selected zones. However, according to the results of our research, the concentrations of mobile forms of metals exceeded the concentrations of total forms of the same metals by approximately two times (but stayed within the limits of MAC)

Mitochondria-targeted mesoporous silica nanoparticles noncovalently modified with triphenylphosphonium cation: Physicochemical characteristics, cytotoxicity and intracellular uptake

Novel nanocomposite system based on mesoporous silica nanoparticles (MSNs) noncovalently modified with hexadecyltriphenylphosphonium bromide (HTPPB) has been prepared, thoroughly characterized and used for encapsulation of model cargo Rhodamine B (RhB). The high encapsulation efficacy of this dye by HTPPB-modified mesoporous particles was demonstrated by spectrophotometry and thermography techniques. The bioavailability of MSN@HTPPB was testified. Cytotoxicity assay revealed that a marked suppression of M−HeLa cancer cells (epithelioid carcinoma of the cervix) occurs at concentration of 0.06 μg/mL, while the higher viability of Chang liver normal cell line was preserved in the concentration range of 0.98–0.06 μg/mL. Hemolysis assay demonstrated that only 2% of red blood cells are destructed at ~ 30 μg/mL concentration. This allows us to select the most harmless compositions based on MSN@HTPPB with minimal side effects toward normal cells and recommend them for the development of antitumor formulations. Fluorescence microscopy technique testified satisfactory penetration of HTPPB-modified carriers into M−HeLa cells. Importantly, modification of the MSN with HTPPB is shown to promote efficient delivery to mitochondria. To the best of our knowledge, it is one of the first successful examples of noncovalent surface modification of the MSNs with lipophilic phosphonium cation that improves targeted delivery of loads to mitochondria