Self-assembly of carbon based nanoparticles films by Langmuir-Blodgett method

Carbon nanoparticles are a class of materials with extraordinary properties. In the past three decades, four major types of carbon nanoparticles were synthesized and investigated: fullerenes, carbon nanotubes, graphene and carbon quantum dots. One of the main properties of such materials is their hydrophobic nature. At the same time, Langmuir–Blodgett (LB) method the for deposition of thin films of hydrophobic materials provides the possibility to design thin films of different carbon-based nanoparticles with special architectures and features enabling their usage in various fields, particularly in electronics and biomedicine. In this review, the state of art of LB thin films of four types of carbon-based nanoparticles and their application in electronics and biomedicine are presented. The breakthrough in this field was finally achieved by application of carbon quantum dots soluble in solvents optimized for LB deposition

Phloroglucinol-Based Carbon Quantum Dots/Polyurethane Composite Films: How Structure of Carbon Quantum Dots Affects Antibacterial and Antibiofouling Efficiency of Composite Films

Nowadays, bacteria resistance to many antibiotics is a huge problem, especially in clinics and other parts of the healthcare system. This critical health issue requires a dynamic approach to produce new types of antibacterial coatings to combat various pathogen microbes. In this research, we prepared a new type of carbon quantum dots based on phloroglucinol using the bottom-up method. Polyurethane composite films were produced using the swell–encapsulation–shrink method. Detailed electrostatic force and viscoelastic microscopy of carbon quantum dots revealed inhomogeneous structure characterized by electron-rich/soft and electron-poor/hard regions. The uncommon photoluminescence spectrum of carbon quantum dots core had a multipeak structure. Several tests confirmed that carbon quantum dots and composite films produced singlet oxygen. Antibacterial and antibiofouling efficiency of composite films was tested on eight bacteria strains and three bacteria biofilms

Antibacterial and Antibiofouling Activities of Carbon Polymerized Dots/Polyurethane and C60/Polyurethane Composite Films

The cost of treatment of antibiotic-resistant pathogens is on the level of tens of billions of dollars at the moment. It is of special interest to reduce or solve this problem using antimicrobial coatings, especially in hospitals or other healthcare facilities. The bacteria can transfer from medical staff or contaminated surfaces to patients. In this paper, we focused our attention on the antibacterial and antibiofouling activities of two types of photodynamic polyurethane composite films doped with carbon polymerized dots (CPDs) and fullerene C60. Detailed atomic force, electrostatic force and viscoelastic microscopy revealed topology, nanoelectrical and nanomechanical properties of used fillers and composites. A relationship between the electronic structure of the nanocarbon fillers and the antibacterial and antibiofouling activities of the composites was established. Thorough spectroscopic analysis of reactive oxygen species (ROS) generation was conducted for both composite films, and it was found that both of them were potent antibacterial agents against nosocomial bacteria (Klebsiela pneumoniae, Proteus mirabilis, Salmonela enterica, Enterococcus faecalis, Enterococcus epidermis and Pseudomonas aeruginosa). Antibiofouling testing of composite films indicated that the CPDs/PU composite films eradicated almost completely the biofilms of Pseudomonas aeruginosa and Staphylococcus aureus and about 50% of Escherichia coli biofilms

Procédé de fabrication d'un nanomatériau ayant des propriétés antibactériennes, matériau à base de celui-ci, et son utilisation

Method for manufacture of a nanocomposite material with antibacterial properties comprising mixing of a polymer and a filler, while the amount of the filler in the mixture is max 10% wt, and the polymer is selected from polyamide, acrylics, butadiene, dialkylphtalate, dimethylsiloxanes, isoprene, isobutylene, styrene structural units and the filler is hydrophobic carbon quantum dots hCQD which are prepared by bottom-up condensation reaction of polyoxyethylene-polyoxypropylene-polyoxyethylene. Nanocomposite material is adapted to cause an oxidative stress and reduce viability of bacteria, while the controlled antibacterial activity is activated after its illumination with blue light in the visible region having a wavelength of 420 - 470 nm.L'invention concerne un procédé de fabrication d'un matériau nanocomposite ayant des propriétés antibactériennes, comprenant le mélange d'un polymère et d'une charge, la quantité de la charge dans le mélange étant au maximum de 10 % en poids, et le polymère étant choisi parmi le polyamide, les acryliques, le butadiène, le dialkylphtalate, les diméthylsiloxanes, l'isoprène, l'isobutylène, les unités structurelles de styrène et la charge étant composée de points quantiques de carbone hydrophobes hCQD qui sont préparés par réaction de condensation ascendante de polyoxyéthylène-polyoxypropylène-polyoxyéthylène. Le matériau nanocomposite est conçu pour provoquer un stress oxydatif et réduire la viabilité des bactéries, tandis que l'activité antibactérienne contrôlée est activée après son éclairage avec une lumière bleue dans la région visible avec une longueur d'onde de 420 à 470 nm.Date of publication and mention of the grant of the patent: 27.01.2021 Bulletin 2021/04; Application number: 18719324.8, Date of filing: 27.02.2018; International application number: PCT/SK2018/050004; International publication number: WO 2018/160142(07.09.2018 Gazette 2018/36); European Patent Office: EP3589682, Date: 27.01.2021

Comparative MD Study of Inhibitory Activity of Opaganib and Adamantane-Isothiourea Derivatives toward COVID-19 Main Protease M^pro

In this study, the inhibitory potency of four adamantly- isothiourea derivatives (compounds 1 [4-bromobenzyl (Z)-N′-(adamantan-1-yl)-4-phenylpiperazine-1-carbothioimidate], 2 [3,5-bis(trifluoromethyl)benzyl (Z)-N′-(adamantan-1-yl)-4-phenylpiperazine-1-carbothioimidate], 3 [4-bromobenzyl (Z)-N-(adamantan-1-yl)morpholine-4-carbothioimidate] and 4 [3,5-bis(trifluoromethyl)benzyl (Z)-N-(adamantan-1-yl)morpholine-4-carbothioimidate]) was evaluated against SARS-CoV-2 targeted proteins. The investigated compounds 1–4 possess a similar structure to opaganib, which is used in studies like a potential drug for COVID-19 treatment. Since examined adamantly-isothiourea derivatives (1–4) shown broad-spectrum of antibacterial activity and significant in vitro cytotoxic effects against five human tumor cell lines and shown similarity in structure with opaganib, it was of interest to study their inhibitory potency toward some SARS-CoV-2 proteins such as SARS-CoV-2 main protease Mpro and mutation of SARS-CoV-2 Spike (S) Protein D614G. The inhibitory potency of studied compounds is examined using molecular docking and molecular dynamic simulations. The results of molecular docking simulations indicate compound 1 as the most prominent candidate of inhibition of SARS-CoV-2 main protease Mpro (▵Gbind=11.24 kcal/mol), while almost the same inhibition potency of all studied compounds is exhibited toward D614G. Regarding the results obtained by molecular dynamic simulations, compounds 1 and 4 possess similar inhibitory potency toward SARS-CoV-2 main protease Mpro as opaganib (▵Gbind (Formula presented.) 40 kcal/mol)

Ab Initio Study of Structural, Electronic and Optical Properties of Edge-Functionalized Graphene Quantum Dots

Graphene quantum dots (GQD) are nano-particles small enough to exhibit unique electronic and optical properties that results from quantum confinement and edge effects. Unlike graphene they exhibit opening of the HOMO-LUMO band gap responsible for their unique optoelectronic properties high photoluminescence (PL) quantum yield, excellent photobleaching resistance and photostability, low citotoxicity, good biocompatibility, high solubility in various solvents, exceptional electrochemical activity and physicochemical stability. These characterisics of the GQDs make them suitable for a wide range of applications from biomedical applications such as diagnostics and therapy, to susteanable agricultural and environmental appications. In this respect carbon-based quantum dots such as GQDs, present promising candidates for usage in biosensing and fluorescence bioimaging applications, allowing a fast, more sensitive and more selectable detection and diagnosis. As biocompatible nanoparticles, they also have the potential to revolutionize the prospects of photodynamic therapy (PDT) in clinical treatments of cancer [1] and other diseases, antibacterial [2] and preventive antivirus PDT [3], being applied as photosensitizer agents. In a meanwhile comprehensive biomedical studies should pave the way for safe and efficient use of carbon-based quantum dots in clinical applications. In the present work, we investigate the effects of size and shape variation, as well as edge-functionalization on the structural and optical properties of GQDs, using the first-principles study based on the density functional theory (DFT) and time-dependent density functional theory (TD-DFT). We investigate edge-functionalized GQDs, with oxygen-containing –OH and –COOH groups, different shapes, such as hexagonal, triangular and rectangular and zigzag/armchair edge configuration, as well as variation of size, in tailoring the optoelectronic properties and photoluminescence behaviour of GQDs leading to a wide variety of applications.29th International Symposium on Analytical and Environmental Problems : Proceedings; November 13-14, 2023; Szeged, Hungary

Principi procene dobrobiti riba u farmskim uslovima gajenja

For several decades fish welfare has been subject of many researches, and the interest for this subject is connected with the fact that fish can feel pain and suffering. In addition to this stressors' mechanisms of action and their consequences are similar in mammals and fish. Assessment of welfare for farmed fish is based on the same principles as for terrestrial farm animals. However, special methods of collecting data are needed due to morphological characteristics of fish and properties of their environment. In the world and in our country, researches of different ways of fish welfare assessment are being conducted, especially based on non-invasive techniques such as monitoring of behaviour. In this paper a review of basic principles and methods used in assessment of farmed fish welfare is given.Dobrobit riba je već nekoliko decenija predmet brojnih istraživanja, a zainteresovanost za ovu temu povezana je sa činjenicom da ribe mogu da osećaju bol i patnju. Osim toga, mehanizmi i posledice delovanja stresora kod riba vrlo su slični onima kod sisara. Procena nivoa dobrobiti kod farmski uzgajanih riba zasniva se na istim principima kao kod kopnenih farmskih životinja. Međutim, voda kao životna sredina riba i njihove morfološke specifičnosti zahtevaju posebne metode prikupljanja podataka. U svetu i kod nas se istražuju različiti načini procene dobrobiti riba, naročito oni koji se zasnivaju na neinvazivnim postupcima, kao što je praćenje ponašanja. U ovom radu dat je prikaz osnovnih principa i metoda koji se koriste u proceni dobrobiti farmski gajenih riba

Numerical simulation of fire spread in terminal 2 of Belgrade airport

This paper concern the results of software fire spread process prototype in terminal 2 of Belgrade airport using computational fluid dynamics. Numerical simulation of fire for the most critical fire scenario has been performed, primarily obtaining the space and time distribution of: velocity, pressure, temperature, and smoke concentration, assuming that HVAC systems have been switched off and all doors on the evacuation ways have been opened, just as the fire started Also, two simulations have been compared of the smoke ventilation and not ventilation for the same scenario. Within the framework of the results presentation, isosurfaces of constant temperature (100 degrees C) and smoke concentration (4000 ppm) are presented, based on the numerical simulation. Progression of these surfaces along the terminal 2 coincides to the experimental and experience evidence, forming the plume zone just above the fireplace, and spreading in the zone of underground ceiling and stairwell openings

Fatty acid profile in muscles of carp (cyprinus carpio l.) Raised in a semi-intensive production system fed with grains, pelleted and extruded feed

The effects of grains, pelleted and extruded feed on the fatty acid content in carp meat has not been examined yet. In this work, we present evidence that the high carbohydrate content in all three types of feed causes oleic acid to predominate in all meat samples. A higher PUPA content in the meat of fish fed with granulated feed was detected. The extruded feed diet led to 69% greater n-3, and 53% lower n-6 fatty acid contents. Their ratio is thus 2.64-fold higher than in meat of carp fed with pelleted feed. A higher content of n-3 fatty acids in fish fed with extruded feed was the consequence of higher DNA (1.6 times) and EPA (3.3 times) contents. The detected differences could be the consequence of the thermal treatment of extruded feed that makes the proteins, carbohydrates and lipids more accessible to fish than in a pelleted feed