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Engineered nanoparticles (NPs) are being studied for their potential to harm humans and the environment. Biological activity, toxicity, physicochemical properties, fate, and transport of NPs must all be evaluated and/or predicted. In this work, we explored the influence of metal oxide nanoparticle facets on their toxicity towards bronchial epithelial (BEAS-2B), Murine myeloid (RAW 264.7), and E. coli cell lines. To estimate the toxicity of metal oxide nanoparticles grown to a low facet index, a quantitative structure–activity relationship ((Q)SAR) approach was used. The novel model employs theoretical (density functional theory calculations) and experimental studies (transmission electron microscopy images from which several particle descriptors are extracted and toxicity data extracted from the literature) to investigate the properties of faceted metal oxides, which are then utilized to construct a toxicity model. The classification mode of the k-nearest neighbour algorithm (EnaloskNN, Enalos Chem/Nanoinformatics) was used to create the presented model for metal oxide cytotoxicity. Four descriptors were identified as significant: core size, chemical potential, enthalpy of formation, and electronegativity count of metal oxides. The relationship between these descriptors and metal oxide facets is discussed to provide insights into the relative toxicities of the nanoparticle. The model and the underpinning dataset are freely available on the NanoSolveIT project cloud platform and the NanoPharos database, respectively. [ABSTRACT FROM AUTHOR]

Experimental methods of investigations of nanoparticle (NP)-protein interactions are limited, because they require a high amount of samples and the NPs tend to interfere with spectral results. Therefore, molecular modeling is a commonly accepted tool in such kind of investigations. Examining the molecule toxicity on the molecular level, we usually want to know, mainly, the location of the ligand on the protein surface and what is an influence of such a contact on the biological functions of the protein. In the presented work, we demonstrate that multiple-docking of the ligand from a random start and with large grid volume, to let the ligand search the whole protein surface, allows to find the best binding sites and gives reliable results considering ligand-protein interactions. In the present work, we have constructed six models of bronchoalveolar lavage fluids proteins: α1-antitripsin, albumin, ceruloplasmin, lactoferrin, lysozyme, and transferrin with fullerene, C utilizing molecular docking methods. The most probable results were examined with steered molecular dynamics (SMD) to see, if the simple docking method is able to predict the fullerene binding affinity. Albumin and lysozyme were already widely investigated and literature data is available for their complexes with fullerene C and/or its derivatives. Thus, we used these two models as a reference set to validate the used molecular modeling methods. With our best knowledge, interactions of the remaining four proteins with NPs have never been investigated in detail before. Our results indicate that fullerene C readily interacts with all studied proteins and may have a large impact on their biological functions. [ABSTRACT FROM AUTHOR]

We propose spectral density distribution moments as molecular descriptors. We apply the new descriptors for developing a QSPR model that predicts the logarithmic values of subcooled liquid vapor pressure. We consider the infrared spectra of chloronaphthalenes. [ABSTRACT FROM AUTHOR]

Nowadays nanotechnology is one of the most promising areas of science. The number and quantity of synthesized nanomaterials increase exponentially, therefore it is reasonable to expect that comprehensive risk assessment based only on empirical testing of all novel engineered nanoparticles (NPs) will very soon become impossible. Hence, the development of computational methods complementary to experimentation is very important. Quantitative structure-property relationship (QSPR) and quantitative structure-activity relationship (QSAR) models widely used in pharmaceutical chemistry and environmental science can also be modified and adopted for nanotechnology to predict physico-chemical properties and toxicity of empirically untested nanomaterials. All QSPR/QSAR modelling activities are based on experimentally derived data. It is important that, within a given data set, all values should be consistent, of high quality and measured according to a standardized protocol. Unfortunately, the amount of such data available for engineered nanoparticles in various data sources (i.e. databases and the literature) is very limited and seldom measured with a standardized protocol. Therefore, we have proposed a framework for collecting and evaluating the existing data, with the focus on possible applications for computational evaluation of properties and biological activities of nanomaterials. [ABSTRACT FROM AUTHOR]

We have estimated degradation half-lives of both brominated and chlorinated dibenzo- p-dioxins (PBDDs and PCDDs), furans (PBDFs and PCDFs), biphenyls (PBBs and PCBs), naphthalenes (PBNs and PCNs), diphenyl ethers (PBDEs and PCDEs) as well as selected unsubstituted polycyclic aromatic hydrocarbons (PAHs) in air, surface water, surface soil, and sediments (in total of 1,431 compounds in four compartments). Next, we compared the persistence between chloro- (relatively well-studied) and bromo- (less studied) analogs. The predictions have been performed based on the quantitative structure-property relationship (QSPR) scheme with use of k-nearest neighbors (kNN) classifier and the semi-quantitative system of persistence classes. The classification models utilized principal components derived from the principal component analysis of a set of 24 constitutional and quantum mechanical descriptors as input variables. Accuracies of classification (based on an external validation) were 86, 85, 87, and 75% for air, surface water, surface soil, and sediments, respectively. The persistence of all chlorinated species increased with increasing halogenation degree. In the case of brominated organic pollutants (Br-OPs), the trend was the same for air and sediments. However, we noticed that the opposite trend for persistence in surface water and soil. The results suggest that, due to high photoreactivity of C-Br chemical bonds, photolytic processes occurring in surface water and soil are able to play significant role in transforming and removing Br-OPs from these compartments. This contribution is the first attempt of classifying together Br-OPs and Cl-OPs according to their persistence, in particular, environmental compartments. [ABSTRACT FROM AUTHOR]

Molecular descriptors from calculations at the level of Density Functional Theory (B3LYP/6-311++G**) were effectively applied in QSPR estimation of supercooled liquid vapour pressures (PL) for individual chloronaphthalene congeners. The estimated values of log PL varied from 1.05 Pa to 5.6 × 10-5 Pa, depending on the number of chlorine substituents present in the molecule and the substitution pattern. Comparison of the five chemometrical methods of modelling (approaches) led to the final conclusion, that the use of relatively simple PLS combined with one of the variable pre-selection algorithms (UVE or GA) seems to be the optimal choice in such computational studies for persistent organic pollutants. The best GA-PLS model was characterized by the value of root mean square error of prediction RMSEP = 0.108 logarithmic Pascal units. [ABSTRACT FROM AUTHOR]

Computational n-octanol/water partition coefficients data for 75 chloronaphthalene congeners based on the Ghose, Pritchet, and Crippen algorithm; the Moriguchi method; and two QSPR models with principal component regression and partial least-squares (PLS) regression calculations are presented. Chloronaphthalenes log K OW data obtained after PLS are characterized by the lowest root mean square error (RMSEP = 0.0190), whereas results from the Ghose, Pritchet, and Crippen algorithm are characterized by the worst predictive ability (RMSEP = 0.4191). Minimal values of log K OW of chloronaphthalenes ranged between 3.57 and 3.90 for 1-chloronaphthalene, whereas maximal values ranged between 6.36 and 7.19 for octachloronaphthalene. [ABSTRACT FROM AUTHOR]

Based on available toxicological data and matrix of structural descriptors 7-ethoxyresorufin-O-diethylase (EROD) and luciferase (luc) inducing potency for 75 congeners of chloronaphthalene was predicted using quantitative structure– activity relationships (QSAR) strategy. The most active congeners in EROD and luciferase bioassays were CN congeners nos. 75 and 67. Some empirical rules describing toxic PCNs were formulated. [ABSTRACT FROM AUTHOR]

The concentrations of 63 congeners of chloronaphthalene (CN; polychlorinated naphthalenes, PCNs) in dated on ˜500 B.C. to 2000 sediment core from the Lake Kitaura in Japan have been quantified by HRGC/HRMS after double column HPLC fractionation. Sediment from the Lake Kitaura showed a time-dependent pattern in distribution of CNs since the ˜500 B.C. Starting from the 1910s the total CNs content increased accelerating from the 1960s, and, in parallel, the pattern of CN congeners has changed with a substantial increase in contribution from the penta, hexa, hepta, and octaCN. The total CNs content normalized to dry weight of sediment peaked out in the layer dated on 1984–1985, and next nearly two-fold decreased with further gradually decreasing concentration in 1987–2000. An occurrence of tri and tetraCNs in deep sediment layers corresponded to preindustrial synthesis and use of CNs seems to be connected to relatively greater water solubility and mobility in the pore water of those CN homologue groups. Based on CN congener pattern and results of multivariate analysis three main layers were separated in the sediment core. Starting from 1981 the emission sources related to combustion marker congeners become substantial contributors to flux of annually deposited CNs, while relative significance of the evaporative source marker congeners decreased after 1985. The annual flux of CNs into sediments of the Lake Kitaura was 0.073–0.31 pg/cm2 before 1926, increased to 5.5–14 pg/cm2 in 1963–1970 and next sharply increased to 50–107 pg/cm2 in 1971–1985, and after that decreased to 17 pg/cm2 in 1997–2000. [ABSTRACT FROM AUTHOR]

Fourteen species of wild growing mushrooms and surface (0–10 cm) soils were collected near Lake Wdzydze in the northern part of Poland in 1996–1997 to understand the status of mercury pollution. Concentrations of mercury in mushrooms varied between 100±30 and 2400±1900 ng g-1 dry matter in caps and 60±1 and 1300±1500 ng g-1 dry matter in stalks. Concentrations of mercury in underlying soil were between 30±1 and 140±120 ng g-1 dry matter (between 36±18 and 63±100 ng g-1 depending on the soil type). Bioconcentration factors (BCF: concentrations in mushroom/concentration in soil) of total mercury were between 2.3±1.1 and 90±110 for caps, and between 2.1±1.0 and 53±56 for stalks. Scaly tooth (Sarcodon imbricatum) contained the greatest concentrations of mercury in the flesh. However, there was no significant relationship (p >: 0.05) between mercury content in the fruiting bodies of this species to soil mercury concentrations. A significant (p < 0.01) positive relationship between mercury content in caps to underlying soil was noted for European cow bolete (Suillus bovinus), while a negative relationship between mercury content in caps and stalks to underlying soil was observed for Sandy knight-cap (Tricholoma flavovirens), Shaggy scale-head (Pholiota squaroso-adiposa), Gypsy mushroom (Rozites caperata) and Pine spike cap (Chroogomphus rutilus). [ABSTRACT FROM AUTHOR]

Concentrations and composition profiles of polychlorinated biphenyls (PCBs) were investigated in composite samples of 10 species of edible fish from the Gulf of Gdańsk, in the southern part of the Baltic Sea, Poland, to understand the status of contamination and possible human exposure risk. Apart from the total PCBs, planar non-ortho (IUPAC nos 77, 126, 169) and mono-ortho (nos 105, 114, 118, 123, 156, 157, 167, 189) chlorobiphenyls were also quantified and their dioxin-like toxicity assessed. The absolute total PCB concentrations in fish ranged from 43 to 490 ng g[sup -1] wet wt (910-11000 ng g[sup -1] lipids), while of TCDD TEQs of planar members were from 0.15 to 3.1 pg g[sup -1] wet wt (8.1-81 pg g[sup -1] lipids). The penta- and hexa-CBs usually comprised 70-80% of the total PCBs and were followed by hepta-, tetra- and tri-CBs, and for a specific site tri- and tetra-CBs comprised as much as 22%. Among the individual CB congeners, nos 118, 153 (+132) and 138 (+160 +163 +164) were the most abundant, while no. 110 comprised between 6.8 and 9.3% of the total PCBs in some species. Principal component analysis (PCA) was applied to examine the interdependences among CB congeners in the factor space. The PCA model and cluster analyses were further used to examine site- and species-specific differences and similarities of PCB composition, and the results are discussed. An assessed daily intake rate of TCDD TEQ of planar PCBs with the fishmeal of the Gulf of Gdańsk in the 1990s was between 78 and 96 pg per capita or between 1.3 and 1.6 pg kg[sup -1] body weight. [ABSTRACT FROM AUTHOR]