Ultrasound exfoliation of inorganic analogues of graphene

High-intensity ultrasound exfoliation of a bulk-layered material is an attractive route for large-scale preparation of monolayers. The monolayer slices could potentially be prepared with a high yield (up to 100%) in a few minutes. Exfoliation of natural minerals (such as tungstenite and molybdenite) or bulk synthetic materials (including hexagonal boron nitride (h-BN), hexagonal boron carbon nitride (h-BCN), and graphitic carbon nitride (g-C(3)N(4))) in liquids leads to the breakdown of the 3D graphitic structure into a 2D structure; the efficiency of this process is highly dependent upon the physical effects of the ultrasound. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) were employed to verify the quality of the exfoliation. Herein, this new method of exfoliation with ultrasound assistance for application to mono- and bilayered materials in hydrophobic and hydrophilic environments is presented

Improvement of Orange II Photobleaching by Moderate Ga 3+

Highly photoactive Ga3+-doped anatase modification of titania was prepared by homogeneous hydrolysis of aqueous solutions mixture of titanium oxo-sulphate TiOSO4 and gallium(III) nitrate with urea. Incorporation of Ga3+ into the anatase lattice has a clear positive effect on the photocatalytic activity under UV and Vis light irradiation up to a certain extent of Ga. Ga3+ doping decreased the size of the crystallites, increased surface area, and affected texture of the samples. Higher amount of gallium leads to the formation of a nondiffractive phase, probably photocatalytically inactive. The titania sample with 2.18 wt.% Ge3+ had the highest activity during the photocatalysed degradation in the UV and visible light regions; the total bleaching of dye Orange II was achieved within 29 minutes. Ga concentration larger than 5% (up to 15%) significantly inhibited the growth of the anatase crystal domains which formed the nondiffractive phase content and led to remarkable worsening of the photobleaching efficiency

Clinical importance and mechanisms of action of morphine and methadone

This bachelor thesis deals with gathering the information regarding the clinical importance of opioid drugs, particularly morphine and methadone, and their mechanism of action. Awareness of health professionals and the general public on opioid is inadequate. This evokes unnecessary anxiety of uninformed patients by the treatment of this kind of drugs. This thesis contains information that should know each worker in the health sector. It deals with pharmacodynamics, which is important for understanding the effects of drugs, both biochemical and physiological as well as pharmacokinetics, which describes how the body compensates for the delivered drug. Usage of morphine and methadone is currently irreplaceable. Morphine is a strong analgesic effective control of pain of different origin. Methadone is used for the substitutive treatment of people addicted to opioids. The side effects occurring during the treatment with opioids are acceptable with regard to severe pain, which is attenuated by opioids

Clinical importance and mechanisms of action of morphine and methadone

This bachelor thesis deals with gathering the information regarding the clinical importance of opioid drugs, particularly morphine and methadone, and their mechanism of action. Awareness of health professionals and the general public on opioid is inadequate. This evokes unnecessary anxiety of uninformed patients by the treatment of this kind of drugs. This thesis contains information that should know each worker in the health sector. It deals with pharmacodynamics, which is important for understanding the effects of drugs, both biochemical and physiological as well as pharmacokinetics, which describes how the body compensates for the delivered drug. Usage of morphine and methadone is currently irreplaceable. Morphine is a strong analgesic effective control of pain of different origin. Methadone is used for the substitutive treatment of people addicted to opioids. The side effects occurring during the treatment with opioids are acceptable with regard to severe pain, which is attenuated by opioids

Determination of volatile isoprenoids as water stress markers of spruce resistance against bark beetle

Isoprenoids are important components of conifer resin and represent an important part of constituted defence system against herbivores and pathogens. Drought is one of the most important factors that influences the tree physiology and resitance. Due to decreased turgor of resin canal cells, the water insufficiency affects the pressure of the resin and thereby the ability of trees to physically prevent pathogen or herbivore invasion by effective outpouring of the resin. In addition, drought can also change the resin composition and thus can influence the quality of volatiles emitted by the tree. The Norway spruce, Picea abies, is the predominant species of production forests in moderate climate zone. Bark beetles, Ips typographus, represent the most important pest species of spruce. In general, pioneer bark beetles use host volatiles to orient themselves toward the tree suitable for colonization and in many species host volatiles synergize bark beetle aggregation pheromones. Thus the host volatile composition could affect significantly host colonization. This diploma thesis studied the influence of drought on the production and composition of isoprenoid volatile organic compounds in 80 - 100 years old spruce trees. Using I. typographus antennae as biological detectors, we also studied which resin..

Removal of anthracycline cytostatics from aquatic environment: Comparison of nanocrystalline titanium dioxide and decontamination agents.

Anthracyclines are a class of pharmaceuticals used in cancer treatment have the potential to negatively impact the environment. To study the possibilities of anthracyclines (represented by pirarubicin and valrubicin) removal, chemical inactivation using NaOH (0.01 M) and NaClO (5%) as decontamination agents and adsorption to powdered nanocrystalline titanium dioxide (TiO2) were compared. The titanium dioxide (TiO2) nanoparticles were prepared via homogeneous precipitation of an aqueous solution of titanium (IV) oxy-sulfate (TiOSO4) at different amount (5-120 g) with urea. The as-prepared TiO2 samples were characterized by XRD, HRSEM and nitrogen physisorption. The adsorption process of anthracycline cytostatics was determined followed by high-performance liquid chromatography coupled with mass spectrometry (LC-MS) and an in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) technique. It was found that NaClO decomposes anthracyclines to form various transformation products (TPs). No TPs were identified after the reaction of valrubicin with a NaOH solution as well as in the presence of TiO2 nanoparticles. The best degree of removal, 100% of pirarubicin and 85% of valrubicin, has been achieved in a sample with 120 grams of TiOSO4 (TIT120) and TiO2 with 60 grams (TIT60), respectively

A Study of Methylene Blue Dye Interaction and Adsorption by Monolayer Graphene Oxide

The graphene oxide (GO) interaction with methylene blue (MB) cationic dye was studied in an aqueous solution at different pH during MB adsorption. The mutual interaction of MB with GO surface was studied and evaluated by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The π-π and electrostatic interaction of MB with GO surface are the main types of interactions, and the XRD data show the monomeric arrangement of MB cation with GO. The GO surface functional groups and point of zero charge (PZC) were determined by acid-base titration. Suitability of zeta-potential measurement and acid-base titration method was briefly discussed. The quality of prepared GO was evaluated by Raman spectroscopy, XRD, and atomic force microscope (AFM). The experimental adsorption equilibrium data were analyzed using Langmuir, Langmuir-Freundlich, Freundlich, and Temkin isotherms. The GO maximum adsorption capacity increases with higher pH, that is ascribed to the facile interaction of negatively charged GO with positively charged MB structure

The effects of formation and functionalization of graphene-based membranes on their gas and water vapor permeation properties

The gas and water vapor permeabilities of graphene-based membranes can be affected by the presence of different functional groups directly bound to the graphene network. In this work, one type of carboxylated graphene oxide (GO-COOH) and two types of graphene oxide synthesized i) under strong oxidative conditions directly from graphite (GO-1) and ii) under mild oxidative conditions from exfoliated graphene (GO-2) were used as precursors of self-standing membranes prepared with thicknesses in the range of 12–55 μm via slow-vacuum filtration preparation method. It was observed that the permeabilities for all tested gases decreased in order GO-2 > GO-1 > GO-COOH and depended on both the arrangement of graphene sheets and their functionalization. The GO-1 membrane with a high content of oxygen-containing groups showed the best performance for water vapor permeability. The GO-2 membrane with a thickness of 43 μm exhibited a disordered GO sheet morphology and, therefore, unique gas-separation performance towards H2/CO2 gas pair, showing high hydrogen permeability while keeping extremely high H2/CO2 ideal selectivity that exceeds the Robeson 2008 upper bound of polymer membranes