Molecular modeling of nanofibers surfaces modified by antibacterial agents

Tato diplomová práce propojuje dva rychle se rozvíjející vědecké směry, odvětví nanovláken a počítačové modelování chemických struktur. Slibným přínosem této práce má být pochopení chování různých antibakteriálních činidel na nanovlákenném povrchu s možností budoucího vytvoření nových antibakteriálních systémů. Jako antibakteriální molekuly byl pro tuto práci vybrán nystatin, chlorhexidin a dodecyltrimethylamonium bromid, které byly následně umisťovány na povrch tvořený řetězci nylonu 6,6 a kyseliny polymléčné. Veškeré činnosti probíhaly v prostředí modelovacího programu Materials Studio 4.2. Sledovány byly především typy interakcí mezi molekulou a povrchem, simulován byl také pohyb molekuly po povrchu, pomocí čehož byly na závěr stanoveny difúzní koeficienty molekul na daných typech povrchů.This diploma thesis connects two fast growing disciplines, the nanofiber industry and computer modelling of chemical structures. The promising contribution of this work is to understand the behaviour of various antibacterial agents on the surface of nanofibres with the possibility of creating new antibacterial systems in the future. Nystatin, chlorhexidine and dodecyltrimethylammonium bromide were selected as antibacterial molecules for this work, which where subsequently placed on the surface of the nylon 6,6 and polylactic acid chains. All activities took place in the modelling environment of the Materials Studio 4.2. In particular, the types of interactions between the molecule and the surface were observed, as well as the movement of molecules on the surface, by which diffusion coefficient of the molecules on the given surface types were determined.9360 - Centrum nanotechnologiívýborn

Detached house with relaxation centre in Praha - Horní Počernice

Tématem této bakalářské práce je návrh rodinného domu s relaxačním centrem. Pozemek, na němž má stavba ležet, se nachází v Praze-Horních Počernicích. Terén je mírně svažitý. Objekt má mít tři nadzemní podlaží a také má být částečně podsklepený. Stavba bude kompletně zateplena. Konstrukce krovu bude sedlová. Půdorysně bude zaujímat netradiční tvar.The theme of this bachelor thesis is designing a detached house with a relaxation centre. Land, where the building will be situated, is in Praha-Horní Pocernice. Terrain is lightly sloping. It is supposed to be three overground storeys in the house and the building should be designed as partly cellared. The building will be thermally insulated. The construction of the roof will be saddle. The platform will be untraditionally shaped.

Complete genome sequence of Streptococcus agalactiae strain 01173, isolated from Kuwaiti wild fish

© 2020 Santi et al. Here, we report the complete genome of piscine Streptococcus agalactiae 01173 serotype Ia, which was generated using long-read sequencing technology. The bacteria were isolated from wild fish displaying signs of streptococcosis, from a fish kill incident in Kuwait

Analysis of the effect of catalytic additives in the agricultural waste combustion process

This paper presents the research results of the effect of using calcium oxide and potassium permanganate on the combustion of pellets from wheat bran and beet pulp. The measurements were performed in the technical laboratory of the Centre of Energy Utilization of Non-Traditional Energy Sources in Ostrava. The research examined the effect of the use of chemical substances on the amount of air pollutants from biomass thermal conversion in a low-power boiler and the process temperature. First, we performed technical and elementary analyses of agricultural waste. The raw material was then comminuted, mixed with a selected additive, pelletized, and finally burned in a low-power boiler. The additive was added in three proportions: 1:20, 1:10, and 1:6.67 (i.e., 15%) relative to the fuel weight. The combustion process efficiency was measured using a flue gas analyzer and three thermocouples attached to the data recorder. From the measurement results, we were able to determine the percentage reduction of pollutant emissions into the atmosphere (CO, NOx, and SO2) due to the use of additives. Because emission standards are becoming increasingly stringent and fuel and energy prices are rising, the results presented in this article may be useful to agri-food processing plants that want to manage these materials thermally.Web of Science1510art. no. 352

A História da Alimentação: balizas historiográficas

Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

Effects of Structure and Composition of Adsorbents on Competitive Adsorption of Gaseous Emissions: Experiment and Modeling

Dangerous gases arising from combustion processes must be removed from the air simply and cheaply, e.g., by adsorption. This work is focused on competitive adsorption experiments and force field-based molecular modeling of the interactions at the molecular level. Emission gas, containing CO, NO, SO2, and CO2, was adsorbed on activated carbon, clay mineral, silicon dioxide, cellulose, or polypropylene at two different temperatures. At 20 °C, activated carbon had the highest NO and SO2 adsorption capacity (120.83 and 3549.61 μg/g, respectively). At 110 °C, the highest NO and SO2 adsorption capacity (6.20 and 1182.46 μg/g, respectively) was observed for clay. CO was adsorbed very weakly, CO2 not at all. SO2 was adsorbed better than NO, which correlated with modeling results showing positive influence of carboxyl and hydroxyl functional groups on the adsorption. In addition to the wide range of adsorbents, the main novelty of this study is the modeling strategy enabling the simulation of surfaces with pores of controllable sizes and shapes, and the agreement of the results achieved by this strategy with the results obtained by more computationally demanding methods. Moreover, the agreement with experimental data shows the modeling strategy to be a valuable tool for further adsorption studies

Effect of crystal structure on nanofiber morphology and chemical modification; design of CeO2/PVDF membrane

Layered crystal structures tend to form flat platelet-like crystallites, and nanofibers having such a structure exhibit strip-like morphology. Crystallographic plane forming the dominant flat surface of the nanofibers can be used for surface modification with catalytically active nanoparticles capable of anchoring to the dominant flat surface. In this study, polyvinylidene fluoride (PVDF) nanofibers exhibiting strip-like morphology and longitudinal folding were prepared using wire electrospinning, and surface modified with CeO2 nanoparticles. Experimental characterization of the CeO2/PVDF membrane using (high-resolution) scanning electron microscopy and X-ray photoelectron spectroscopy was supplemented by a force field-based molecular modeling. The modeling has shown that the dominant PVDF(100) plane is suitable for anchoring the CeO2 nanoparticles. In this respect, the PVDF(100) plane is comparable to the less exposed fluorine-oriented PVDF(010) plane, and both planes show stronger interaction with CeO2 compared to hydrogen-oriented PVDF(010) plane. Molecular modeling also revealed preferred crystallographic orientations of anchored CeO2 nanoparticles: these are the catalytically active planes (100), (110), and (111). The successful surface modification and the finding that CeO2 nanoparticles on the dominant PVDF(100) surface can preferentially exhibit these crystallographic orientations thus provides the possibility of various practical applications of the CeO2/PVDF membrane.Web of Science110art. no. 10756

The influence of structural properties on the adsorption capacities of microwave-assisted biochars for metazachlor removal from aqueous solutions

Biochars, carbonaceous materials prepared without the usage of chemical agents, are porous materials capable of adsorbing pollutants from ground-and surface waters. In this study, biochars prepared from various types of agricultural biomass were tested for the adsorptive removal of herbicide metazachlor from an aqueous environment. Banana wastes, red mombin seeds, corncob, cocoa pod husk, and coffee husk were used as precursors. Biochars were prepared with the aid of microwave treatment. The effect of precursor type on structure and adsorption was examined. Adsorption was controlled by a multistep mechanism, adsorption kinetics followed predominantly the pseudo-second-order model, adsorption isotherms suited to both Langmuir and Freundlich isotherms, depending on the particular biochar. Significant differences between the structural properties and adsorption capacities of the examined biochars were observed. The best adsorption properties for metazachlor uptake were observed for banana waste-based biochar, which had large, elongated pores, highest volume of micropores and one of the highest contents of polar functional groups. The maximum adsorption capacity, calculated from Langmuir isotherm, was 146.01 mg.g(-1), The adsorption capacity at equilibrium, obtained by kinetic measurements, was 27.25 mg.g(-1), the kinetic constant was 5.14.10- 3 dm3.min(-1) (both calculated from pseudo-second order model). Molecular modeling revealed that metazachlor molecules preferably entered two layer wide cavities containing one COOH group with their pyrazole rings.Web of Science103art. no. 10800