China
Africa
Explore chapters and articles related to this topic
Suspension Plasma Spray
Published in Navid Hosseinabadi, Hossein Ali Dehghanian, Suspension Plasma Spray Coating of Advanced Ceramics, 2022
Navid Hosseinabadi, Hossein Ali Dehghanian
Otsuka et al. investigated the mechanical and antibacterial properties of titania gray/hydroxyapatite SPS coatings on the surface of Ti substrates for biomedical applications recently. Plasma-sprayed HAp composite contains components such as medium crystalline HAp and TCP, the dissolution of which can increase the deposition of amorphous calcium phosphate in vivo. Suspended plasma-coated composite coatings containing TiO2 with mixed Magneli phases, such as Ti4O7 and Ti3O5, typically exhibit photocatalytic activity. The increased amount of TiO2 proliferates the mechanical properties and surface strength by suppressing strain accumulation at the interface between the Ti substrate and the composite coating. It is noteworthy that HAp/gray titania coating SPS without amino acid complex can provide effective antibacterial properties against Escherichia coli due to exposure to visible light. The underlying mechanism of enhanced mechanical and antibacterial properties observed by the addition of TiO2 in their study is identified. Increased antibacterial properties of HAp/SPS gray titania coating can be attributed to the high number of Magneli phase compounds and high wettability. Small grain size was observed due to the use of submicron particles, which was beneficial for antibacterial activity.
Liquid Chromatography
Published in Ernő Pungor, A Practical Guide to Instrumental Analysis, 2020
There are several additives used in HPLC to resolve racemic mixture. Some examples will be given below. For separation of racemic amino acids in aqueous eluent metal optically pure amino acid complex can be used. For example, copper(2)-l-proline can be used for separation of underivatized amino acid enantiomers on an ion-exchange column. It is postulated that stereoselectivity can be explained with the complex stability differences in aqueous medium. If the l-proline is changed to d-proline, the elution order will change as well. If the metal complex additives contain hydrophobic segment then the additive will adsorb onto the surface of the reserved-phase material, and retention of the enantiomers can affect the stereoselectivity of both phases.
Study of metal-amino acid [Cr(III)-Trp]2+ complex and ninhydrin reaction: role of gemini micellar solution on rate constant
Published in Molecular Physics, 2021
Malik Abdul Rub, Dileep Kumar, Abdullah M. Asiri, Yousef G. Alghamdi
In each experiment, requisite volumes of buffer, chromium-amino acid complex and surfactant were kept in a reaction glass vessel. Vessel having a mixture was placed in a thermostated water/paraffin oil bath at a fixed temperature and was connected to a water condenser to stop any evaporation. N2 was steamed through the vessel for creating inert environment. A fixed volume of ninhydrin placed separately in the thermostated was poured to the mixture to initiate the experiment. The experiment was, then, monitored using a spectrophotometer. All kinetic measurements were performed for triple times. The values of rate constant were determined by recording absorbance at regular time intermissions at maximum wavelength ( = 390 nm). Complete information on the determination of reaction rates and kinetic procedure were provided in the studies reported previously [48–54].
Enhanced photocatalytic decolorization of Congo red dye with surface-modified zinc oxide using copper(II)–amino acid complex
Published in Inorganic and Nano-Metal Chemistry, 2020
The decrease in the absorbance value of the peaks shows a decrease in the concentration of the complex in solution and that difference is taken as the amount of the complex adsorbed onto the ZnO nanoparticles. The adsorption of the complex is further confirmed from the color change of the ZnO nanoparticles to blue. The blue coloration on the ZnO nanoparticles was retained even during the dye degradation process showing a very strong interaction between the complex and the ZnO nanoparticles. A 10% of copper introduction, in the form of complex, has taken place in the C-ZnO nanoparticles using the amino acid complex and is found to be the maximum to which the copper can be introduced even with a saturated solution of the amino acid complex. The introduction of copper is confirmed from the corresponding copper peaks in the EDAX pattern.
Two-component organogelators: combination of Nε-alkanoyl-L-lysine with various N-alkanoyl-L-amino acids: additional level of hierarchical control
Published in Soft Materials, 2018
Mehmet Çolak, Deniz Barış, Murat Evcil, Nadir Demirel, Halil Hoşgören
The synthesis of Nε-alkanoyl-L-lysine derivatives is the key step because there is very limited literature. Synthesis of Nε-acetyl derivatives of these compounds to be used in the synthesis of target molecules was first made and patented by Takizawa K., Yoshida R., in 1975 (29). The use of these compounds is owned by Japanese Ajinomoto Co., Inc., Tokyo, Japan. Another synthesis method is to convert the Thallium (I) salt of N-hydroxysuccinimide to its corresponding N-hydroxysuccinimide active ester with the corresponding acid chlorides; based on the acylation of the Nε −lysine amino acid with the active esters formed. This method provides a selective (chemoselective) acylation of the amino group in the side chain of basic amino acids such as lysine (30,31). Another method is to form complex between the α-amino group of lysine with the copper (II). Then acylation of Nε of lysine. The procedure is completed by removal of the copper (II) ion with the 8-hydroxyquinoline from the acylated amino acid complex. In this method, only acetic anhydride is used as an acylating agent. Acetyl lysine 15N labeled was prepared according to this procedure (32). Our method has advantages that the synthesis procedure is simple and forward. And, the synthesis step is short when compared with the literature methods.