Topological spaces with the Freese--Nation property II

The aim of this paper is to study the class of spaces with the FNS property and \pi-\FNS property. We shown that compact spaces with the FNS property for some base consisting of cozero-sets are openly generated spaces and spaces with the \pi-\FNS property are skeletally generated spaces

The Banach–Mazur game and domain theory

We prove that player α has a winning strategy in the Banach–Mazur game on a space X if and only if X is F-Y countably π-domain representable. We show that Choquet complete spaces are F-Y countably domain representable. We give an example of a space, which is F-Y countably domain representable, but which is not F-Y π-domain representable

Topological spaces with the Freese-Nation property

We give a proposal of generalization of the Freese–Nation property for topological spaces. We introduce a few properties related to Freese–Nation property: FNS; FN; FNS ; FNI. This article presents some relationship between these concepts. We show that spaces with the FNS property satisfy ccc and any product of such spaces also satisfies ccc. We show that all metrizable spaces have the FN property

Ambivalent attitudes towards social media

The use of social media (SM) is prevalent not only in private, but also in professional areas, and its overall involvement in our lives has grown immensely over the past decade. According to Bishop (2018), this is a phenomenon unlike anything seen throughout history. Previous studies on SM have analysed this subject unilaterally – giving greater emphasis to the positive or negative impact on its users. This novel article analyses the problem of the co-existence of opposing emotions towards SM based on the example of Facebook. Data from 274 young respondents (since teenagers and young adults spend on average 2–3 hours a day connected to SM sites, more so than other groups) (Healey, 2017), were collected on various areas of SM usage perception. The results present the existence of ambivalent attitudes towards Facebook threefold: as a place for building relationships, as a source of knowledge about the life of friends, and as a source of information. The article raises doubt as to what extent SM has an impact on their users in the future. The issue of SM affecting the user (no matter their age) generally focuses on the negative aspects (SM are being blamed for increasing mental health problems among young people) (Girl Effect team, 2018); therefore, the fidings here suggest that a balanced perspective is required, also including some positive aspects

Two Decades of 4D-QSAR: A Dying Art or Staging a Comeback?

A key question confronting computational chemists concerns the preferable ligand geometry that fits complementarily into the receptor pocket. Typically, the postulated ‘bioactive’ 3D ligand conformation is constructed as a ‘sophisticated guess’ (unnecessarily geometry-optimized) mirroring the pharmacophore hypothesis—sometimes based on an erroneous prerequisite. Hence, 4D-QSAR scheme and its ‘dialects’ have been practically implemented as higher level of model abstraction that allows the examination of the multiple molecular conformation, orientation and protonation representation, respectively. Nearly a quarter of a century has passed since the eminent work of Hopfinger appeared on the stage; therefore the natural question occurs whether 4D-QSAR approach is still appealing to the scientific community? With no intention to be comprehensive, a review of the current state of art in the field of receptor-independent (RI) and receptor-dependent (RD) 4D-QSAR methodology is provided with a brief examination of the ‘mainstream’ algorithms. In fact, a myriad of 4D-QSAR methods have been implemented and applied practically for a diverse range of molecules. It seems that, 4D-QSAR approach has been experiencing a promising renaissance of interests that might be fuelled by the rising power of the graphics processing unit (GPU) clusters applied to full-atom MD-based simulations of the protein-ligand complexes

A study on the static field of a point charge in three-dimensional electrodynamics

The static field potential in quantum electrodynamics in the space of three dimensions (QED3) produced by a point charge was investigated taking into account the polarization of the vacuum. The polarization operator is taken in the N-1 approximationwhichwas previously used to study the dynamic violation of chiral symmetry inQED3. An approximate analytical analysis is accompanied by numerical calculations; there is a good quantitative agreement between the results obtained using these methods. The case of massive dynamical fermions is considered. The limiting transition to the massless case is analyzed, as well as the confinement problem occurring in this model

Utilization of energy crops and sewage sludge in the process of co-gasification for sustainable hydrogen production

The increasing world energy demand driven by economic growth and technical development contributes to the severe depletion of conventional energy resources and various environmental issues. The need for the employment of low-emission, highly efficient technologies of thermochemical conversion, flexible in terms of both raw resources and product applications is declared, when the utilization of solid, alternative fuels is considered. Gasification is the proven technology of lower unit emission of contaminants and higher efficiency than combustion systems, as well as versatile applicability of the synthesis gas, as its main product. While the conversion of fossil fuels in gasification systems is technically mature, the co-utilization of biomass and waste still requires research and optimization in various technical and economic aspects. In this paper, the results of experimental work on co-gasification of energy crops biomass and sewage sludge with steam to produce hydrogen-rich gas are presented. The process is performed at 700, 800 and 900°C under atmospheric pressure. The experimental results are analyzed with the application of the Hierarchical Clustering Analysis. The optimal results in terms of hydrogen production in co-gasification of selected biomass and sewage sludge are observed for Helianthus tuberosus L. blends of 10% w/w of sewage sludge content at 900°C

The use of MoStBioDat for rapid screening of molecular diversity

MoStBioDat is a uniform data storage and extraction system with an extensive array of tools for structural similarity measures and pattern matching which is essential to facilitate the drug discovery process. Structure-based database screening has recently become a common and efficient technique in early stages of the drug development, shifting the emphasis from rational drug design into the probability domain of more or less random discovery. The virtual ligand screening (VLS), an approach based on high-throughput flexible docking, samples a virtually infinite molecular diversity of chemical libraries increasing the concentration of molecules with high binding affinity. The rapid process of subsequent examination of a large number of molecules in order to optimize the molecular diversity is an attractive alternative to the traditional methods of lead discovery. This paper presents the application of the MoStBioDat package not only as a data management platform but mainly in substructure searching. In particular, examples of the applications of MoStBioDat are discussed and analyze

The Bioconversion of Sewage Sludge to Bio-Fuel: The Environmental and Economic Benefits

This paper aims to analyze the economic feasibility of generating a novel, innovative biofuel— bioenergy—obtained from deposit bio-components by means of a pilot installation of sewage sludge bio-conversion. Fuel produced from sewage sludge biomass bears the potential of being considered a renewable energy source. In the present study, 23 bioconversion cycles were conducted taking into consideration the different contents, types of high carbohydrate additives, moisture content of the mixture as well as the shape of the bed elements. The biofuel was produced using post fermentation sewage sludge for industrial energy and heat generation. Based on the presented research it was concluded that the composite biofuel can be co-combusted with hard coal with the optimal percentage share within the range of 20–30% w/w. Sewage sludge stabilized by means of anaerobic digestion carried out in closed fermentation chambers is the final product. The average values of the CO2, CO, NO, NOx and SO2 concentrations in flue gas from co-combustion of a bioconversion product (20% w/w) and coal were 5.43%, 1903 ppm, 300 ppm, 303 ppm and 179 ppm, respectively. In total, within a period of 4.5 years of the plant operation, 1853 Mg of fuel was produced and successfully co-combusted with coal in a power plant. The research demonstrated that in the waste water treatment sector there exists energy potential in terms of calorific value which translates into tangible benefits both in the context of energy generation as well as environmental protection. Over 700,000 Mg of bio-sewage sludge is generated annually in Poland. According to findings of the study presented in the paper, the proposed solution could give 970,000 Mg of dry mass of biomass qualified as energy biomass replacing fossil fuels

Self-organizing neural networks for modeling robust 3D and 4D QSAR: application to dihydrofolate reductase inhibitors

We have used SOM and grid 3D and 4D QSAR schemes for modeling the activity of a series of dihydrofolate reductase inhibitors. Careful analysis of the performance and external predictivities proves that this method can provide an efficient inhibition model