Effect of ZrO2 on the physicochemical properties and biological properties of β-SiAlON–ZrO2 composite ceramics

2021 ◽  
Vol 47 (1) ◽  
pp. 1244-1252
Author(s):  
Liguo Zhang ◽  
Can Zhang ◽  
Enxia Xu ◽  
Lu Gao ◽  
Huiping Chen ◽  
...  
Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3224 ◽  
Author(s):  
Beata Kaczmarek

As a phenolic acid, tannic acid can be classified into a polyphenolic group. It has been widely studied in the biomedical field of science because it presents unique antiviral as well as antibacterial properties. Tannic acid has been reported to present the activity against Influeneza A virus, Papilloma viruses, noroviruses, Herpes simplex virus type 1 and 2, and human immunodeficiency virus (HIV) as well as activity against both Gram-positive and Gram-negative bacteria as Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Enterococcus faecalis, Pseudomonas aeruginosa, Yersinia enterocolitica, Listeria innocua. Nowadays, compounds of natural origin constitute fundaments of material science, and the trend is called “from nature to nature”. Although biopolymers have found a broad range of applications in biomedical sciences, they do not present anti-microbial activity, and their physicochemical properties are rather poor. Biopolymers, however, may be modified with organic and inorganic additives which enhance their properties. Tannic acid, like phenolic acid, is classified into a polyphenolic group and can be isolated from natural sources, e.g., a pure compound or a component of a plant extract. Numerous studies have been carried out over the application of tannic acid as an additive to biopolymer materials due to its unique properties. On the one hand, it shows antimicrobial and antiviral activity, while on the other hand, it reveals promising biological properties, i.e., enhances the cell proliferation, tissue regeneration and wound healing processes. Tannic acid is added to different biopolymers, collagen and polysaccharides as chitosan, agarose and starch. Its activity has been proven by the determination of physicochemical properties, as well as the performance of in vitro and in vivo studies. This systematics review is a summary of current studies on tannic acid properties. It presents tannic acid as an excellent natural compound which can be used to eliminate pathogenic factors as well as a revision of current studies on tannic acid composed with biopolymers and active properties of the resulting complexes.


1976 ◽  
Vol 159 (3) ◽  
pp. 661-665 ◽  
Author(s):  
F Gauthier ◽  
H Mouray

1. Rat α2 acute-phase macroglobulin was isolated from turpentine-injected rats by Sephadex G-200 chromatography and ion-exchange chromatography on DEAE-cellulose. This method, since it does not include (NH4)2SO4 treatment, allows the study of the physicochemical as well as the biological properties of the molecule. 2. The purity of the preparation was demonstrated by ultracentrifugation, polyacrylamide-gel electrophoresis, fused “rocket” immunoelectrophoresis as well as double immunodiffusion. 3. The rat α2 acute-phase macroglobulin was characterized in terms of its main physical and chemical properties. Its isoelctric point was determined by isoelectrofocusing to be 4.55; s020,w was 18.4S and E1%/1cm at 278 nm was 6.8. The mol.wt. was determined by light-scattering to be 770000. 4. The amino acid content was compared with that of rat α1 macroglobulin and was found very similar. The carbohydrate composition of α2 acute-phase macroglobulin was determined to be: hexose, 4.25%; glucosamine, 3.4%; sialic acid, 2%; fucose, 0.2%. From these results it was concluded that α2 acute-phase macroglobulin, although a typical acute-phase reactant, possesses the characteristic physicochemical properties of α macroglobulins.


2020 ◽  
Vol 26 (36) ◽  
pp. 4648-4657
Author(s):  
Patricia Rocha de Araújo ◽  
Bruno Fonseca-Santos ◽  
Ana Carolina Kogawa ◽  
Hérida Regina Nunes Salgado ◽  
Marlus Chorilli

Aims: A review of analytical methods for the determination of hypericin in foods, herbal, biological and pharmaceutical matrices. Background: Hypericin (HYP) is a naturally-occurring pigment obtained from some plants of the genus Hypericum. Although HYP has been known for many years, it has recently attracted attention due to its varied biological properties, such as anti-inflammatory and antidepressant activity and it is also an efficient photosensitizer. Objective: The objective of this review is to provide insights into the physicochemical properties of HYP, as well as to report the analytical methods existing in the literature and official compendia for different matrices. Methods: The survey data were collected by Google Scholar® and Scopus® using keys terms. Result: Analytical methods involving HYP are mainly concerned with the quality control of pharmaceutical preparations, foods, beverages, biological samples and drug delivery systems using different types of analysis methods. Some difficulties have also been identified due to the physicochemical properties of HYP. It presents great solubility in alkaline solutions, organic bases and common polar organic solvents. Conclusion: It can be analyzed by thin layer chromatography, spectrophotometry in the ultraviolet region, but the most commonly used method is by HPLC. HYP presents monographs in the American, British and European Pharmacopoeias, however, the methods of analysis are not yet harmonized.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
A. Nasiru ◽  
N. Ismail ◽  
M. H. Ibrahim

Ruminants are important sources of meat and milk. Their production is associated with manure excretion. Estimates of over 3,900,000 million metric tonnes of manure are produced daily from ruminants worldwide. Storage and spread of this waste on land pose health risks and environmental problems. Efficient and sustainable way of handling ruminant manure is required. Composting and vermicomposting are considered two of the best techniques for solid biomass waste management. This paper presents vermicomposting as an effective tool for ruminant manure management. Vermicomposting is a mesophilic biooxidation and stabilisation process of organic materials that involves the joint action of earthworm and microorganism. Compared with composting, vermicomposting has higher rate of stabilisation and it is greatly modifying its physical and biochemical properties, with low C : N ratio and homogenous end product. It is also costeffective and ecofriendly waste management. Due to its innate biological, biochemical and physicochemical properties, vermicomposting can be used to promote sustainable ruminant manure management. Vermicomposts are excellent sources of biofertiliser and their addition improves the physiochemical and biological properties of agricultural soils. In addition, earthworms from the vermicomposting can be used as source of protein to fishes and monogastric animals. Vermicompost can also be used as raw materials for bioindustries.


RSC Advances ◽  
2015 ◽  
Vol 5 (19) ◽  
pp. 14294-14304 ◽  
Author(s):  
Loredana S. Dorobantu ◽  
Greg G. Goss ◽  
Robert E. Burrell

The purpose of this study was to characterize the interactive effects of light and aging on physicochemical properties and antimicrobial activity of nanocrystalline silver wound dressings Acticoat that might find their way into the environment.


2020 ◽  
Vol 22 (1) ◽  
pp. 115
Author(s):  
Magdalena Paczkowska-Walendowska ◽  
Natalia Rosiak ◽  
Ewa Tykarska ◽  
Katarzyna Michalska ◽  
Anita Płazińska ◽  
...  

Progressive increase in bacterial resistance has caused an urgent need to introduce new antibiotics, one of them being oxazolidinones with their representative tedizolid. Despite the broad spectrum of activity of the parent tedizolid, it is characterized by low water solubility, which limits its use. The combination of the active molecule with a multifunctional excipient, which is cyclodextrins, allows preservation of its pharmacological activity and modification of its physicochemical properties. Therefore, the aim of the study was to change the dissolution rate and permeability through the model membrane of tedizolid by formation of solid dispersions with a cyclodextrin. The research included identification of tedizolid-hydroxypropyl-β-cyclodextrin (tedizolid/HP-β-CD) inclusion complex by thermal method (Differential Scanning Colorimetry), spectroscopic methods (powder X-ray diffraction, Fourier-Transform Infrared spectroscopy), and molecular docking. The second part of the research concerned the physicochemical properties (dissolution and permeability) and the biological properties of the system in terms of its microbiological activity. An increase in the dissolution rate was observed in the presence of cyclodextrin, while maintaining a high permeation coefficient and high microbiological activity. The proposed approach is an opportunity to develop drug delivery systems used in the treatment of resistant bacterial infections, in which, in addition to modifying the physicochemical properties caused by cyclodextrin, we observe a favorable change in the pharmacological potential of the bioactives.


2018 ◽  
pp. 55-59
Author(s):  
T. V. Kravchenko ◽  
O. I. Panasenko ◽  
Ye. G. Knysh

Purposeful synthesis of derivatives of 1,2,4-triazole is one of the most important branches of modern pharmaceutical science Modern pharmaceutical market of domestic medicines requires constant updates of existing range. It makes possible the synthesis of new compounds with a predicted biological activity. The main advantage of derivatives of 1,2,4-triazole is high efficiency and low toxic. That is promising factor for creation of new chemical compounds. Analysis of literary data of past few years has showed that there is not enough information about synthesis, physical, chemical and biological properties of derivatives of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol in the literature. So synthesis and further research of derivatives of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol is topical. The research took place at the Department of toxicological and inorganic Chemistry of Zaporizhzhia State Medical University (the head of the department – professor O. I. Panasenko). During the work the research were the physicochemical properties of newly synthesized of compounds in accordance with the methods described in the State Pharmacopoeia of Ukraine. As starting substance was used 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol obtained by cyclization of of potassium 2-atsetilgidrazinkarboditioata in the medium hydrazine hydrate. It is planned to research of the compounds obtained in the antimicrobial, act-protective, antioxidative and hypolipidemic activity. 9 new compounds of ylidene derivatives of 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol were synthesized in a research. The structure of the new synthesized of substances was confirmed by with by means of modern of instrumental methods analysis (1H-PMR-spectroscopy, chromato-mass-spectrometry, elemental analysis). The obtained data is possible to use in purposeful synthesis for the further research of biologically active compounds.


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