scholarly journals Antimicrobial Activity and Degradation of Superhydrophobic Magnesium Substrates in Bacterial Media

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1100
Author(s):  
Alexandre M. Emelyanenko ◽  
Valery V. Kaminsky ◽  
Ivan S. Pytskii ◽  
Kirill A. Emelyanenko ◽  
Alexander G. Domantovsky ◽  
...  
Keyword(s):  
Barrier Properties ◽  
Sodium Polyphosphate ◽  
Continuous Contact ◽  
Superhydrophobic Coatings ◽  
High Level ◽  
Corrosive Environments ◽  
Microbiologically Induced Corrosion ◽  
Phosphate Buffered Saline ◽  
Controllable Degradation ◽  
Dispersion Composition

The interest in magnesium-based materials is promoted by their biocompatibility, their bioresorbability, and their recently discovered antibacterial potential. Until now, the widespread use of magnesium alloys in different corrosive environments was inhibited by their weakly controllable degradation rate and poorly understood microbiologically induced corrosion behavior. To better understand the degradation and usability of magnesium-based alloys, in this study we have fabricated superhydrophobic coatings on a magnesium-based alloy, and analyzed the behavior of this alloy in bacterial dispersions of Pseudomonas aeruginosa and Klebsiella pneumoniae cells in phosphate-buffered saline. It was shown that the immersion of such coatings in bacterial dispersions causes notable changes in the morphology of the samples, dependent on the bacterial dispersion composition and the type of bacterial strain. The interaction of the superhydrophobic coatings with the bacterial dispersion caused the formation of biofilms and sodium polyphosphate films, which provided enhanced barrier properties in magnesium dissolution and hence in dispersion medium alkalization, eventually leading to the inhibition of magnesium substrate degradation. The electrochemical data obtained for superhydrophobic samples in continuous contact with corrosive bacterial dispersions for 48 h indicated a high level of anticorrosion protection.

scholarly journals Antimicrobial activity and degradation of superhydrophobic magnesium substrates in bacterial media

2021 ◽  
Author(s):  
Alexandre M. Emelyanenko ◽  
Valery V. Kaminsky ◽  
Ivan S. Pytskii ◽  
Kirill A. Emelyanenko ◽  
Alexander G. Domantovsky ◽  
...  
Keyword(s):  
Barrier Properties ◽  
Sodium Polyphosphate ◽  
Superhydrophobic Coatings ◽  
High Level ◽  
Corrosive Environments ◽  
Microbiologically Induced Corrosion ◽  
Phosphate Buffered Saline ◽  
Controllable Degradation ◽  
Dispersion Composition ◽  
Antibacterial Potential

AbstractThe interest in magnesium-based materials is promoted by their biocompatibility, bioresorbability, and by their recently found antibacterial potential. Until now the widespread use of magnesium alloys in different corrosive environments was inhibited by their weakly controllable degradation rate and poorly understood microbiologically induced corrosion behavior. To better understand the degradation and usability of magnesium-based alloys, in this study we have fabricated the superhydrophobic coatings on top of magnesium-based alloy and analyzed the behavior of this alloy in bacterial dispersions of Pseudomonas aeruginosa and Klebsiella pneumoniae cells in phosphate buffered saline. It was shown that immersion of such coatings into bacterial dispersions causes notable changes in the morphology of the samples, dependent on the bacterial dispersion composition and the type of bacterial strain. The interaction of superhydrophobic coatings with the bacterial dispersion caused the formation of biofilms and sodium polyphosphate films, which provided enhanced barrier properties for magnesium dissolution and hence for dispersion medium alkalization, eventually leading to inhibition of magnesium substrate degradation. Electrochemical data obtained for superhydrophobic samples continuously contacted with the corrosive bacterial dispersions during 48 h indicated a high level of anti-corrosion protection.

Formation and Electrochemical Properties of the Hydrophobic Composite Coatings on Aluminum Alloy

2018 ◽  
Vol 386 ◽  
pp. 315-320
Author(s):  
Vladimir S. Egorkin ◽  
Igor E. Vyaliy ◽  
Nikolay S. Sviridov ◽  
Alexander N. Minaev ◽  
Sergey L. Sinebryukhov ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Composite Coatings ◽  
Morphological Structure ◽  
Barrier Properties ◽  
Base Layer ◽  
Layer Composite ◽  
Electrolytic Oxidation ◽  
Different Types ◽  
Plasma Electrolytic ◽  
High Level

Plasma electrolytic oxidation (PEO) of 5754 aluminum alloy in a tartrate electrolyte was carried out to form a base layer. Composite fluoropolymer coatings were obtained on the base layers in two ways allowing the formation of two different types of morphological structure: a continuous polymer film and a multimodal islet relief. The resulted coatings exhibit substantially different wettability along with high level of barrier properties.

scholarly journals A Custom-Made Device for Reproducibly Depositing Pre-metered Doses of Nebulized Drugs on Pulmonary Cells in vitro

2021 ◽  
Vol 9 ◽  
Author(s):  
Justus C. Horstmann ◽  
Chelsea R. Thorn ◽  
Patrick Carius ◽  
Florian Graef ◽  
Xabier Murgia ◽  
...  
Keyword(s):  
Cell Cultures ◽  
Pharmaceutical Formulations ◽  
Barrier Properties ◽  
Liquid Interface ◽  
Bronchial Epithelial ◽  
Pulmonary Epithelial Cells ◽  
Custom Made ◽  
Air Liquid Interface ◽  
Phosphate Buffered Saline

The deposition of pre-metered doses (i.e., defined before and not after exposition) at the air–liquid interface of viable pulmonary epithelial cells remains an important but challenging task for developing aerosol medicines. While some devices allow quantification of the deposited dose after or during the experiment, e.g., gravimetrically, there is still no generally accepted way to deposit small pre-metered doses of aerosolized drugs or pharmaceutical formulations, e.g., nanomedicines. Here, we describe a straightforward custom-made device, allowing connection to commercially available nebulizers with standard cell culture plates. Designed to tightly fit into the approximately 12-mm opening of either a 12-well Transwell® insert or a single 24-well plate, a defined dose of an aerosolized liquid can be directly deposited precisely and reproducibly (4.8% deviation) at the air–liquid interface (ALI) of pulmonary cell cultures. The deposited dose can be controlled by the volume of the nebulized solution, which may vary in a range from 20 to 200 μl. The entire nebulization-deposition maneuver is completed after 30 s and is spatially homogenous. After phosphate-buffered saline (PBS) deposition, the viability and barrier properties transepithelial electrical resistance (TEER) of human bronchial epithelial Calu-3 cells were not negatively affected. Straightforward in manufacture and use, the device enables reproducible deposition of metered doses of aerosolized drugs to study the interactions with pulmonary cell cultures grown at ALI conditions.

scholarly journals Microtitration agglutination for detection of Treponema hyodysenteriae antibody

1978 ◽  
Vol 8 (3) ◽  
pp. 293-298
Author(s):  
L A Joens ◽  
D L Harris ◽  
J M Kinyon ◽  
M L Kaeberle
Keyword(s):  
Agglutination Test ◽  
Test Results ◽  
Absorption Studies ◽  
Treponema Hyodysenteriae ◽  
High Level ◽  
Phosphate Buffered Saline

A microtitration agglutination test for the detection of Treponema hyodysenteriae antibody in swine and rabbit sera is described. The following methods provided the best test results: antigen produced from the spirochete after a culturing period of 36 to 44 h at 38 degrees C, washed antigen inactivated with 0.01% Merthiolate at 4 degrees C for 24 to 36 h, sera heated at 56 degrees C for 30 min, a diluent of phosphate-buffered saline (0.01 M, pH 7.2), and test results read macroscopically after 18 to 24 h of incubation at 38 degrees C. The test enabled detection of antibody against pathogenic T. hyodysenteriae with a high level of consistency and sensitivity. Sera against nonpathogenic T. hyodysenteriae produced low agglutinating titers (less than or equal to 1:8) when reacted against antigen from pathogenic isolates. Inactivated antigen remained stable for 7 to 10 days. Specificity of the reaction in the agglutination test was shown by absorption studies.

A note on the effect of continuous contact with ewes showing regular oestrus and of post-weaning growth rate on the sexual activity of Corriedale rams

1978 ◽  
Vol 27 (3) ◽  
pp. 361-364 ◽  
Author(s):  
C. G. Winfield ◽  
A. W. Makin
Keyword(s):  
Growth Rate ◽  
Sexual Activity ◽  
Breeding Season ◽  
Sexual Experience ◽  
Continuous Contact ◽  
Treatment Groups ◽  
Low Level ◽  
High Level ◽  
Mating Tests

ABSTRACTThirty-six Corriedale rams were weaned at 3 months of age and subjected to four treatments until 2½ years of age. The treatments consisted of two levels of nutrition, with rams on the high level of nutrition being maintained approximately 15% heavier than those on the low level, and two levels of sexual experience. Sexually experienced rams were kept throughout with ewes that were infertile but showed regular oestrus and inexperienced rams were reared in monosexual groups isolated from females except during periodic mating tests. These 2-h tests were carried out at intervals of 3 to 4 months commencing when the rams were 6 months old. Up to 17 months of age there were no significant differences between treatment groups in the development of ability to serve ewes, except that low nutrition reduced the number of rams which had served ewes at 10 months of age. Between 17 and 28 months of age, rams kept with ewes tended to achieve more serves per test during the breeding season than rams kept without ewes.

scholarly journals Comparative Analysis of the Mechanical Behaviour of PEF and PET Uniaxial Stretching Based on the Time/Temperature Superposition Principle

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3295
Author(s):  
Emilie Forestier ◽  
Christelle Combeaud ◽  
Nathanael Guigo ◽  
Guillaume Corvec ◽  
Christophe Pradille ◽  
...  
Keyword(s):  
Physical State ◽  
Mechanical Response ◽  
Superposition Principle ◽  
Barrier Properties ◽  
Experimental Conditions ◽  
Chemical Structures ◽  
Strain Induced Crystallization ◽  
Poly Ethylene ◽  
Time Temperature Superposition Principle ◽  
High Level

Poly(ethylene 2,5-furandicarboxylate), PEF and poly(ethylene terephthalate), PET, are two polyesters with close chemical structures. It leads to similar thermal, mechanical and barrier properties. In order to optimize their stretching, a strategy based on the time/temperature principle is used. The building of master curves, in the linear visco-elastic domain, allows the identification of the experimental conditions for which the two materials are in the same physical state. The initial physical state of the materials is important as, to fit with the industrial constrains, the polymers must reach high level of deformation, and develop strain induced crystallization (SIC). In this paper, the screening of the forming range is described, as well as the mechanical response depending on the stretching settings. Moreover, the same mechanical response can exist for PEF and PET if the same gap from the α-relaxation exists.

scholarly journals Protective effect of cytosine-phosphate-guanosine oligodeoxynucleotide against experimental mastitis induced by Cryptococcus neoformans infection in goats

2017 ◽  
Vol 40 (2) ◽  
pp. 113-123
Author(s):  
Nidhal R. Mahdi
Keyword(s):  
Mammary Gland ◽  
Cryptococcus Neoformans ◽  
Interferon Gamma ◽  
Antibody Titer ◽  
Delayed Type Hypersensitivity ◽  
Phagocytic Index ◽  
Cell Mediated Immunity ◽  
The Right ◽  
High Level ◽  
Phosphate Buffered Saline

     The present study investigated the effect of synthetic non-methylated oligonucleotides containing Cytosine-phosphate-guanosine dinucleotides (Cytosine-phosphate-guanosine oligodeoxynucleotide) on caprine mastitis with Heat Killed Cryptococcus neoformans Ag. 20 healthy local breed does were used with weight ranging of 25-30 Kg and free of mastitis by examination via California Mastitis Test and Somatic Cell Count. The does were allotted into four equal groups, the first group (G1) was treated intramammary with 100μg/kg of Cytosine-phosphate-guanosine oligodeoxy nucleotide on fifth day postpartum in the right mammary gland while the left mammary gland served as control and were infused with sterile phosphate buffered saline. On day 8 postpartum repeat dosages of Cytosine-phosphate-guanosine oligodeoxynucleotide and phosphate buffered saline were infused respectively. On day 9 pp the right mammary gland was infused with 2ml of 2x108 cell/ml of Heat Killed Cryptococcus neoformans Ag. The second group (G2) was infused at day 9 postpartum with 2ml of 2x108 cell/ml of Heat Killed Cryptococcus neoformans Ag in the right mammary gland only. The third group (G3) was left until the challenge test done after one week of immunization in the G1 and G2, by inoculation of 2ml of 5x106 viable C. neoformans in the right mammary gland. The fourth group (G4) was kept as a control receiving 2ml of sterile PBS. Blood samples were collected at 0, 5, 10, 20, 30 and 40 days of the study, to determine the antibody titer by passive haemagglutination assay, while the cell mediated immunity was evaluated by detecting the goat Interferon Gamma by ELISA test and Phagocytic index. Also the cell mediated immunity was determined by delayed type hypersensitivity test after 21 days of immunization. The results showed a significant variation (P≤0.05) between vaccinated groups (G1 and G2) and the control. However, there was a significant increase (P≤0.05) of skin thickness shown after 48 hrs in the G1compared to G2. High level of Interferon Gamma concentration was noticed in the G1 as compared with other groups. Moreover, cell mediated immunity developed effectively in the G1 which was noted by a significant increase (P≤0.05) of phagocytic activity of polymorphonuclear cells. The high level of antibody titer was observed in the G1 as compared with other groups. In conclusion: These results suggest that vaccination with Cytosine-phosphate-guanosine oligodeoxynucleotide plus Heat Killed Cryptococcus neoformans Ag intramammary lead to a good protection of caprine mammary glands against C. neoformans mastitis.

Disinfection of Needleless Catheter Connectors and Access Ports With Alcohol May Not Prevent Microbial Entry: The Promise of a Novel Antiseptic-Barrier Cap

2006 ◽  
Vol 27 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Steve Z. Menyhay ◽  
Dennis G. Maki
Keyword(s):  
Significant Risk ◽  
Bloodstream Infections ◽  
The United States ◽  
Injection Port ◽  
Bloodborne Pathogens ◽  
Continuous Contact ◽  
Colony Forming Units ◽  
To Come ◽  
High Level ◽  
Membranous Septum

Background.Needleless valve connectors for vascular catheters are widely used throughout the United States because they reduce the risk of biohazardous injuries from needlesticks and exposure to bloodborne pathogens, such as human immunodeficiency virus and hepatitis C virus. Patients with long-term central venous catheters are at significant risk of acquiring catheter-related bloodstream infections caused by microbes that gain access through the connection between the administration set and the catheter or an injection port. Most healthcare practitioners wipe the membranous septum of the needleless connector or the injection port with 70% alcohol before accessing it. We report a simulation study of the efficacy of conventional alcohol disinfection before access, compared with that of a novel antiseptic-barrier cap that, when threaded onto a needleless luer-activated valved connector, allows a chlorhexidine-impregnated sponge to come into continuous contact with the membranous surface; after removal of the cap, there is no need to disinfect the surface with alcohol before accessing it.Methods.One hundred five commercial, needleless luer-activated valved connectors, each accessible by a blunt male-connector luer-lock attachment, were purchased from 3 manufacturers and were tested. The membranous septum of each test device was first heavily contaminated with ~105colony-forming units ofEnterococcus faecalisand then was allowed to dry for 24 hours. Fifteen of the contaminated devices were not disinfected (positive controls), 30 were conventionally disinfected with a commercial 70% alcohol pledget, and 60 had the antiseptic cap threaded onto the connector and then removed after 10 minutes. The test connectors were then accessed with a sterile syringe containing nutrient broth media, which was injected, captured on the downstream side of the intraluminal fluid pathway, and cultured quantitatively.Results.All 15 control connectors (100%) showed massive transmission of microorganisms across the membranous septum (4,500-10,000 colony-forming units). Of the 30 connectors accessed after conventional disinfection with 70% alcohol, 20 (67%) showed transmission of microorganisms (442-25,000 colony-forming units). In contrast, of the 60 connectors cultured after application of the novel antiseptic cap, only 1 (1.6%) showed any transmission of microorganisms (P<.001).Conclusions.The findings of this study show that, if the membranous septum of a needleless luer-activated connector is heavily contaminated, conventional disinfection with 70% alcohol does not reliably prevent entry of microorganisms. In contrast, the antiseptic-barrier cap provided a high level of protection, even in the presence of very heavy contamination. This novel technology deserves to be studied in a clinical trial.

Economic viability of the traditional farming system in the Ghouta, Oasis of Damascus, Syria

2003 ◽  
Vol 18 (4) ◽  
pp. 196-205 ◽  
Author(s):  
Sameer K. Alhamidi ◽  
Bengt Håkansson ◽  
Mats Gustafsson
Keyword(s):  
Social Life ◽  
Participant Observation ◽  
Farming System ◽  
Labor Costs ◽  
Traditional Farming ◽  
Continuous Contact ◽  
The Social ◽  
Economic Forces ◽  
High Level ◽  
Satisfactory Income

AbstractThe traditional farming system (TFS) in the Ghouta has been an integral pan of the social life and has contributed to the food supply of Damascus for millennia. Very little is known about this traditional and sustainable system, considered by many as a hindrance to development. This study is an attempt to analyze the economic perfonnance of this system. The objective is to evaluate the economic performance of the TFS and its impact on system viability. Three farms, representing the three different agricultural strategies in this area, were selected for data-collection. Participant observation was used to derive estimates of labor, costs and revenues, which are not recorded by farmers. These three farms formed a base for continuous contact with other farmers in the Ghouta. The average values, after cross-checking with these estimates and other farmers, were used in the economic analysis at three levels: production, family and market level. The production system of the Ghouta is adaptable to economic forces of a major city as the high level of market orientation of the TFS stimulates diversity of farms. It is concluded that the diversified farms managed by farmers in this area provide a satisfactory income, which is in harmony both with the social values and with preserving the system, the overall objective of the farmers.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

Sign in / Sign up

Export Citation Format

Share Document