Theory of relaxed density matrices: Application to second-order response properties

The evaluation of second derivatives of the electronic energy for nonvariational wave functions using an energy functional is discussed. It is shown that, in certain cases, the formation of the first-order relaxed density matrix leads to an efficient algorithm for the calculation of second-order response properties. Detailed formulas are given for second-order Møller–Plesset perturbation theory. © 1994 John Wiley & Sons, Inc.     

An analysis of the electrostatic interaction between nucleic acid bases

Results from several commonly used approximate methods of evaluating electrostatic interactions have been compared to the rigorous, nonexpanded electrostatic energies at both uncorrelated and correlated levels of theory. We examined a number of energy profiles for both hydrogen bonded and stacked configurations of the nucleic acid base pairs. We found that the penetration effects play an extremely important role and the expanded electrostatic energies are significantly underestimated with respect to the ab initio values. Apart from the inability to reproduce the magnitudes of the ab initio electrostatic energy, there are other problems with the available approximate electrostatic models. For example, the distributed multipole analysis, one of the most advanced methods, is extremely sensitive to the basis set and level of theory used to evaluate the multipole moments. Detailed ab initio results are provided that other researchers could use to test their approximate models.     

Influence of Water Treatment and Wastewater Treatment on the Changes in Residues of Important Elements in Drinking Water

Drinking water is the essential medium for food production, and is also needed for direct consumption; while it must be free of harmful substances, it also must have a composition that is beneficial to health. The aim of this study was to evaluate the influence of water and wastewater treatment on reducing the concentrations of zinc (Zn), nickel (Ni), iron (Fe), manganese (Mn), copper (Cu), lead (Pb), and arsenic (As) in the Western Pomerania Voivodeship in Poland. The research was carried out in 2017–2019. The analysis was performed with inductively coupled plasma atomic emission spectrophotometry (ICP-AES). The concentrations of trace elements in drinking water were below maximum acceptable concentrations (MACs). Reductions in the most dangerous elements during water treatment fluctuated from 48.5% (As) to 97% (Pb). Wastewater treatment reduced the concentrations of analyzed elements by a range of 28.6 to 60.8%, and the most toxic elements (Pb and As) by over 50%. Trace element concentrations in treated wastewater were below MAC values, and ranged from 1.15% (Pb) to 6.23% (As) of MACs for toxic elements. The concentrations of both essential elements (Zn, Ni, Fe, Mn, Cu) and toxic elements (Pb, As) in drinking water were below the MACs. Water treatment had a significant (p < 0.05) effect on decreasing trace element concentrations.     

Pattern formation in nonextensive thermodynamics: selection criterion based on the Renyi entropy production

We analyze a system of two different types of Brownian particles confined in a cubic box with periodic boundary conditions. Particles of different types annihilate when they come into close contact. The annihilation rate is matched by the birth rate, thus the total number of each kind of particles is conserved. When in a stationary state, the system is divided by an interface into two subregions, each occupied by one type of particles. All possible stationary states correspond to the Laplacian eigenfunctions. We show that the system evolves towards those stationary distributions of particles which minimize the Renyi entropy production. In all cases, the Renyi entropy production decreases monotonically during the evolution despite the fact that the topology and geometry of the interface exhibit abrupt and violent changes.     

<Emphasis Type="Italic">Yarrowia lipolytica</Emphasis> application as a prospective approach for biosynthesis of pyruvic acid from glycerol

With the problems related to chemical methods of pyruvic acid (PA) synthesis, a fast-growing interest has been observed in research aiming at reducing the production cost of PA by applying biotechnological methods. This study aimed to investigate the potential applicability of Yarrowia lipolytica Wratislavia 1.31 yeast strain for valorisation of pure and crude glycerol through the production of industrially desired PA. Conditions required for the effective PA biosynthesis, i.e., pH value, thiamine concentration, agitation, and substrate concentration, were examined in batch and fed-batch cultivation modes. The efficient production of PA occurred under the limitation of thiamine (1 µg L^?1) and was stimulated by moderate pH (4.5) and agitation (800 rev min^?1) of the culture. Under optimal conditions, Y. lipolytica Wratislavia 1.31 was able to produce 85.2 g L^?1 of PA with volumetric productivity of 0.90 g L^?1 h^?1. The yield of PA biosynthesis reached a high level of 1.03 g g^?1. Obtained results confirmed the aptitude of Y. lipolytica yeast to produce high amounts of PA from simple glycerol-containing media. Presented process was very promising and might be considered as an attractive alternative for currently used chemical methods of PA synthesis.     

13C cross-polarization magic angle spinning NMR and gauge-independent atomic orbital, coupled Hartree-Fock calculations of buspirone analogues. Part 2. Hydrochlorides and perchlorates of 1-arylpiperazine-4-alkylimides.

13C cross-polarization (CP) magic angle spinning (MAS) solid state NMR spectra of hydrochlorides and perchlorates of buspirone analogues (2-5) were recorded. In the spectra for each compound, one set of signals appeared, in agreement with single crystal X-ray diffraction data indicating the presence of one molecule per crystal unit. The resonances of 2-5 hydrochlorides were assigned by comparison with the solution chemical shifts. For perchlorate 2b and diperchlorate 2c, the reasonable assignment of signals was made with the aid of the theoretical studies. Ab initio calculations of the carbon shieldings were performed by means of the GIAO-CHF method for two model systems: perchlorate and diperchlorate of quinoline-(N-methyl)piperazine. As no remarkable differences between carbon chemical shifts of hydrochlorides 3-5 in solid state and in solution were observed, it was concluded that in solution these compounds adopted the same conformation as in the solid state.     

Effects of unsteadiness of the rates of flow on the dynamics of formation of droplets in microfluidic systems

Oscillations of the input rates of flow have a significant impact on the dynamics of formation of droplets in microfluidic systems and on the quality of generated emulsions.     

On the π3He3He coupling

A critical discussion of different methods of estimation of the coupling constant f_π³He³He² is given. It is claimed that at present the best way of obtaining information on this coupling constant is to extrapolate certain differential cross sections, in particular, of the elastic ³He³H scattering, to the pion pole. The resulting value f_π³He³He² = 0.055 ± 0.020 is smaller than the corresponding pion-nucleon value. It supports the expected shadowing effects inside the nucleus but disagrees with other more model-dependent estimations.     

Comment on the real part of the K±p forward scattering amplitude

It is observed that the K_L⁰n→K_S⁰n regeneration measurements require positivity of the real part of the K^?p forward scattering amplitude above p ～ 1.3 GeV/c. This invalidates some of the earlier dispersion relation predictions and the preliminary experimental results from Batavia.