Fjordforsk (Norway)

Thousands of anthropogenic chemicals are released into the environment each year, posing potential hazards to human and environmental health. Toxic chemicals may cause a variety of adverse health effects, triggering immediate symptoms or delayed effects over longer periods of time. It is thus crucial to develop methods that can rapidly screen and predict the toxicity of chemicals, to limit the potential harmful impacts of chemical pollutants. Computational methods are being increasingly used in toxicity predictions. Here, the method of molecular docking is assessed for screening potential toxicity of a variety of xenobiotic compounds, including pesticides, pharmaceuticals, pollutants and toxins deriving from the chemical industry. The method predicts the binding energy of the pollutants to a set of carefully selected receptors, under the assumption that toxicity in many cases is related to interference with biochemical pathways. The strength of the applied method lies in its rapid generation of interaction maps between potential toxins and the targeted enzymes, which could quickly yield molecularlevel information and insight into potential perturbation pathways, aiding in the prioritisation of chemicals for further tests. Two scoring functions are compared, Autodock Vina and the machine-learning scoring function RF-Score-VS. The results are promising, though hampered by the accuracy of the scoring functions. The strengths and weaknesses of the docking protocol are discussed, as well as future directions for improving the accuracy for the purpose of toxicity predictions.<br>

Abstract Vortices and quasiparticles have been studied for 2D systems over the past decades in relation to the development of technologies in quantum electromagnetics, optics, and quantum computation. Deriving new equations for quasiparticles in quantum systems is therefore a critical part of quantum physics. Recently, a supersymmetric wave equation has been developed which describes quasiparticles and vorticity under the influence of electromagnetic fields which has been studied numerically. The analytical solutions of the supersymmetric wave‐equation are presented by increasing levels of energy. It is shown that the derived linear and nonlinear models of the supersymmetric wave‐equation can represent respectively symmetric and asymmetric vorticity formed in a confined rotating torus. The models described are suitable to represent vorticity formed in 2D and 3D electron gas and can be of significant relevance to future research in quantum electromagnetics.

The partitioning of compounds betweenaqueous and other phases is important for predicting toxicity. Althoughthousands of octanol–water partition coefficients have beenmeasured, these represent only a small fraction of the anthropogeniccompounds present in the environment. The octanol phase is often takento be a mimic of the inner parts of phospholipid membranes. However,the core of such membranes is typically more hydrophobic than octanol,and other partition coefficients with other compounds may give complementaryinformation. Although a number of (cheap) empirical methods existto compute octanol–water (log kOW) and hexadecane–water (log kHW) partition coefficients, it would be interesting to know whetherphysics-based models can predict these crucial values more accurately.Here, we have computed log kOW and log kHW for 133 compounds from seven different pollutantcategories as well as a control group using the solvation model basedon electronic density (SMD) protocol based on Hartree–Fock(HF) or density functional theory (DFT) and the COSMO-RS method. Forcomparison, XlogP3 (log kOW) values wereretrieved from the PubChem database, and KowWin log kOW values were determined as well. For 24 of these compounds,log kOW was computed using potential ofmean force (PMF) calculations based on classical molecular dynamicssimulations. A comparison of the accuracy of the methods shows thatCOSMO-RS, KowWin, and XlogP3 all have a root-mean-square deviation(rmsd) from the experimental data of ≈0.4 log units, whereasthe SMD protocol has an rmsd of 1.0 log units using HF and 0.9 usingDFT. PMF calculations yield the poorest accuracy (rmsd = 1.1 log units).Thirty-six out of 133 calculations are for compounds without knownlog kOW, and for these, we provide whatwe consider a robust prediction, in the sense that there are few outliers,by averaging over the methods. The results supplied may be instrumentalwhen developing new methods in computational ecotoxicity. The log kHW values are found to be strongly correlatedto log kOW for most compounds.

Abstract Vortices and quasiparticles in 2D systems are studied for the last decades in relation to the development of technologies in quantum electromagnetics, optics, and quantum computation. Hamiltonians are a fundamental part for studying quasiparticles and vortices, and provide models to calculate the eigenvalues and eigenfunctions that describe a real physical state. By devising supersymmetry, a Hamiltonian for the description of vortices is developed forming in an 2D electron gas and study the numerical solutions under the effects of an alternating electromagnetic field. The numerical analysis shows that vorticity is formed spontaneously without symmetry‐breaking and vortices arise from the boundaries and converge toward the center of the system in a similar fashion to natural hydrodynamic phenomena in water or plasma. Additionally, the equation under damping conditions is studied, a homogenous magnetic field and under the absence of an electromagnetic field. The results and the study of the parameters indicate that the supersymmetic wave equation (SWE) may be a good model equation to describe vorticity for quantum electromagnetics, hydrodynamics, and other physical phenomena in the realm of physical and quantum physical sciences.

Correction for ‘Intriguing properties of unusual silicon nanocrystals’ by Sergio Manzetti et al., RSC Adv., 2015, 5, 78192–78208.

Polycyclic aromatic hydrocarbons are toxic and carcinogenic compounds that occur in the environment and derive from two classes processes: petrogenic and pyrogenic processes. The petrogenic part derives from oil- and drilling activities, including oil disasters, spills, and pollution from industrial sites, refineries, and most importantly traffic exhaust emissions, while the pyrogenic part derives from fires, forest fires, volcanic eruptions, and incineration. PAHs have long degradation periods, and recent studies show high accumulated concentrations in soil, aquatic, and atmospheric environments. Particularly with the advent of the winter season, pollution and pollution migration increases by the atmospheric influences on smog clouds, from air to soil, air to water reserves, and from air to humans. This review maps the recent measurements and concentrations of PAHs worldwide, with particular focus on highly exposed regions such as China, India and former Eastern European countries. Monitoring and mapping the fate of PAH is of particular value to environmental scientists, given the carcinogenic and toxic properties of several PAHs. As also reported in this review, the carcinogenicity and toxicity varies with the chemical and molecular character of PAHs varies with size and shape, and the carcinogenic and toxic effect can be higher according to season, type of fuel and source of pollution, and also by the size of the exposed region/site. PAHs are an ubiquitous pollutant class that has to be included in climate regulations at the same level with CO2 and NOx, given their longer half-life and chemical properties which gives a wide range of toxic derivatives during degradation.

Air, marine, and terrestrial pollution are continuously critical issues to be solved in environmental sciences. Particularly with the recent disaster in the Mexico Gulf and the risk of oil spills from the continuous offshore drilling activities in the North Sea, ecotoxicological profiling requires great attention. Fjord ecosystems are particularly neglected marine ecosystems, which require better surveillance and ecotoxicological profiling. In this context, this study focuses on exploring three potential indicators for aquatic stress [polycyclic aromatic hydrocarbons (PAHs), aromatic amines (AAs), and nitroarenes (NAs)] by the study of their molecular and sub-molecular properties. The results show that the aromatic amine, 4-aminobiphenyl, gains a particularly reactive electronic potential, which can be summarized as a large change in LUMO+2 and HOMO−1 electron orbitals upon metabolic activation in the organism. This change in orbitals increases the overall electrostatic energy of the molecule, inducing a high affinity for DNA-adduct formation. Electronic analysis on nitroarenes shows in addition why 1,6-dinitropyrene is more stable than 1,8-dinitropyrene, and how the electrons favor nitrenium activation on the 6th and 8th carbon. Further analysis shows also that PAHs have a present correlation with hormonal similarity, and that their resemblance to estrogen can be correlated to mutagenicity, contributing to increased ecotoxicity. The electronic analysis of these three types of fossil pollutants shows how their toxicity is exerted from the electronic level and which structural features that determine the level of reactivity and toxicity. The summation of the background and electronic properties of these molecular toxins elucidates that PAHs, aromatic amines, and nitroarenes are all of equal importance as stress indicators for fjord systems, with particular emphasis on PAHs, which also exert hormonal structural similarities as a probable base of their carcinogenic mechanisms.

Construction of wetlands is a possible supplement to best management practices (BMP) at the field level to mitigate phosphorus (P) pollution from agricultural areas. In this paper, annual results from 17 intensively studied wetlands in the cold temperate or boreal climatic zone are reported and analyzed. Surface areas varied from 0.007 to 8.7% of the catchment area. The average total phosphorus (TP) retention varied from 1 to 88%, and the dissolved reactive phosphorus (DRP) retention from -19 to 89%. Retention varied substantially from site to site, indicating the existence of site-specific factors in the catchment and wetlands that influenced the P removal. Factors important for P retention in wetlands were evaluated through multiple statistical analyses by dividing P into two fractions: particulate phosphorus (PP) and DRP. Both relative (%) PP and DRP retention increased with wetland surface area. However, PP retention was not as sensitive as DRP in terms of wetland size and retention: specific PP retention (gram P retention per m(2) and year) decreased as wetland area (A(w)) increased, suggesting the existence of a site-specific optimal wetland to catchment area (A(c)) ratio. Particulate P retention decreased with increasing DRP to TP ratio, while the opposite was found for DRP. Dissolved reactive P retention was higher in new than in old wetlands, while increasing age did not influence PP retention negatively. Effective BMP in the catchment is important to keep the P loss low, because the outlet concentration of P from wetlands is often positively correlated to the input concentration. However, wetlands act as the last buffer in a catchment, since the retention often increases as the P concentration in streams increases.