surface texturing
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An advanced surface engineering process combining micro-texture with a plasma carburising process was produced on CoCrMo femoral head, and their tribological properties were evaluated by the cutting-edge pendulum hip joint simulator coupled with thin film colorimetric interferometry. FESEM and GDOES showed that precipitation-free C S-phase with a uniform case depth of 10μm was formed across the micro-textures after duplex treatment. Hip simulator tests showed that the friction coefficient was reduced by 20% for micro-metre sized texture, and the long-term tribological property of microtexture was enhanced by the C-supersaturated crystalline microstructure formed on the surface of duplex treated CoCrMo, thereby enhancing biotribological durability significantly. In-situ colorimetric interferometry confirmed that the maximum film thickness around texture area was 530nm, indicating that the additional lubricant during sliding motion might provide exceptional bearing life.
... Two Like Surfaces Coming Together in a Medium: -- Surface and Interfacial Energy 196 -- 10.3. ... ... Surface and Adhesion Energies 275 -- 13.14. Surface Energies of Metals 280 -- 13.15. ... ... Surface Charge and Potential of Isolated Surfaces 309 -- 14.13. ... ... Wetting of Rough, Textured, and Chemically -- Heterogeneous Surfaces 434 -- 17.6. ... ... Adhesion of Rough and Textured Surfaces 452 -- 17.10. Plastic Deformations 453 -- 17.11. ...
Third edition xxx, 674 stran : 24 cm il. ;
- MeSH
- fyzikální chemie MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Fyzikální chemie
- NLK Obory
- chemie, klinická chemie
The potential of solar cells have not been fully tapped due to the lack of energy conversion efficiency. There are three important mechanisms in producing high efficiency cells to harvest solar energy; reduction of light reflectance, enhancement of light trapping in the cell and increment of light absorption. The current work represent studies conducted in surface modification of single-crystalline silicon solar cells using wet chemical etching techniques. Two etching types are applied; alkaline etching (KOH:IPA:DI) and acidic etching (HF:HNO3:DI). The alkaline solution resulted in anisotropic profile that leads to the formation of inverted pyramids. While acidic solution formed circular craters along the front surface of silicon wafer. This surface modification will leads to the reduction of light reflectance via texturizing the surface and thereby increases the short circuit current and conversion rate of the solar cells.
- MeSH
- analýza selhání vybavení MeSH
- design vybavení MeSH
- hydroxidy chemie MeSH
- křemík chemie MeSH
- kyseliny chemie MeSH
- nanočástice chemie ultrastruktura MeSH
- povrchové vlastnosti MeSH
- sloučeniny draslíku chemie MeSH
- sluneční energie * MeSH
- smáčivost MeSH
- zdroje elektrické energie * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Microbial transglutaminase (MTG) is an enzyme widely used in the food industry because it creates cross-links between proteins, enhancing the texture and stability of food products. Its unique properties make it a valuable tool for modifying the functional characteristics of proteins, significantly impacting the quality and innovation of food products. In this study, response surface methodology was employed to optimize the fermentation conditions for microbial transglutaminase production by the strain Streptoverticillium cinnamoneum KKP 1658. The effects of nitrogen dose, cultivation time, and initial pH on the activity of the produced transglutaminase were investigated. The significance of the examined factors was determined as follows: cultivation time > nitrogen dose > pH. The interaction between nitrogen dose and cultivation time was found to be crucial, having the second most significant impact on transglutaminase activity. Optimal conditions were identified as 48 h of cultivation with a 2% nitrogen source dose and an initial medium pH of approximately 6.0. Under these conditions, transglutaminase activity ranged from 4.5 to 5.5 U/mL. The results of this study demonstrated that response surface methodology is a promising approach for optimizing microbial transglutaminase production. Future applications of transglutaminase include the development of modern food products with improved texture and nutritional value, as well as its potential use in regenerative medicine for creating biomaterials and tissue scaffolds. This topic is particularly important and timely as it addresses the growing demand for innovative and sustainable solutions in the food and biomedical industries, contributing to an improved quality of life.
We compared the responses of the nesting red-backed shrikes (Lanius collurio) to three dummies of a common nest predator, the Eurasian jay (Garrulus glandarius), each made from a different material (stuffed, plush, and silicone). The shrikes performed defensive behaviour including attacks on all three dummies. Nevertheless, the number of attacks significantly decreased from the stuffed dummy through the plush dummy and finally to the silicone dummy. Our results show that wild birds use not only colours but also other surface features as important cues for recognition and categorization of other bird species. Moreover, the silicone dummy was attacked only when presented after the stuffed or plush dummy. Thus, we concluded that the shrikes recognized the jay only the stuffed (with feathered surface) and plush (with hairy surface) dummies during the first encounter. Recognition of the silicon dummy (with glossy surface) was facilitated by previous encounters with the more accurate model. This process resembles the effect of perceptual priming, which is widely described in the literature on humans.
PURPOSE: Capsular contracture is the most frequent long-term complication after implant-based breast reconstruction or augmentation. The aim of this study was to evaluate the impact of implant surface properties on fibrotic capsule formation in an animal model. MATERIALS AND METHODS: Twenty-four rats received 1 scaled down silicone implant each; 12 of the rats received implants with textured surfaces, and the other 12 received implants with smooth surfaces. After 60 and 120 days, rats in each group underwent 7-Tesla Magnetic Resonance Imaging (MRI) and high-resolution ultrasound (HR-US), and specimens of the capsules were acquired and used to measure capsule thickness through histology, collagen density through picro sirius red staining, and analyses of expression of pro-fibrotic and inflammatory genes (Collagen1-4, TGFb1, TGFb3, Smad3, IL4, IL10, IL13, CD68) through qRT-PCR. Furthermore, MRI data were processed to obtain capsule volume and implant surface area. RESULTS: On day 60, histology and HR-US showed that fibrotic capsules were significantly thicker in the textured implant group with respect to the smooth implant group (p<0.05). However, this difference did not persist on day 120 (p=0.56). Capsule thickness decreased significantly over the study period in both smooth and textured implant groups (p<0.05). Thickness measurements were substantiated by MRI analysis and volumes changed accordingly. Implant surface area did not vary between study dates, but it was different between implant types. On day 60, the density of collagen in the fibrotic capsules was significantly lower in the textured implant group with respect to the smooth group (p<0.05), but again this difference did not persist on day 120 (p=0.67). Collagen 1 and CD68 were respectively over- and under expressed in the textured implant group on day 60. Significant differences in the expression of other genes were not observed. CONCLUSION: Silicone implants with textured surfaces led to temporarily thicker but less dense fibrotic capsules compared with smooth surfaces. 7-Tesla MRI and HR-US are capable for non-invasive in-vivo assessment of capsular fibrosis in an animal model and can provide unique insights into the fibrotic process by 3D reconstruction and surface area measurement.
- Publikační typ
- časopisecké články MeSH
PURPOSE OF THE STUDY Nano-structuring and nano-silver have been extensively studied for improving the antibacterial ability of implants due to their powerful antibacterial activity; however, there is no clinical application as yet. The aim of the study was to determine the antibacterial, antiadhesive and cytotoxic features of Ti6Al4V modified with nano-texturing and silver nano-particles. MATERIAL AND METHODS The nanoparticles were applied on polished and nano-textured Ti6Al4V using sonoreduction. The surface topography, roughness, friction coefficients, hardness and elastic modulus values for prepared top layers were established. The materials were tested for antibacterial and antiadhesion activity using reference bacterial strains (Staphylococcus epidermidis CCM 7221, Staphylococcus aureus MRSA 4591, Enterococcus faecalis CCM 4224, Escherichia coli CCM 3954) and their cytocompatibility. RESULTS A strong antibacterial activity of samples treated with nano-texture and/or silver nanoparticles compared to all the tested bacterial strains at 24 hours was proven. This antibacterial activity was diminishing in relation to Staphylococcus aureusand Enterococcus faecalisat 48 and 72 hours but remained very effective against Staphylococcus epidermidisand Escherichia coli. We also demonstrated antibiofilm activity for samples treated with silver nanoparticles and nano-tubes in experiments lasting 24 and 72 hours. DISCUSSION Our main findings are in agreement with those reported in recent literature. The implant surfaces treated with nano-texture in combination with silver nanoparticles exhibit strong antibacterial and antibiofilm characteristics. Despite there is conclusive evidence of strong antibacterial functioning, why these implant modifications have not been widely applied in clinical practice remains a question. While many obstacles including legislative procedures required for clinical implementation are more or less known, it should be clearly demonstrated that this surface modification does neither harm the patient nor interfere with the long-term survivorship of the implants before their wide-range clinical application. CONCLUSIONS Surface modification of Ti6Al4V with nano-texturing and silver nanoparticles resulted in strong antibacterial and modest antibiofilm effects. Thus, our results confirmed the technological potential of nano-texturing and silver nanoparticles for the improvement of antibacterial properties of implants. Key words:prosthetic joint infection, anti-infective biomaterials, titanium alloy, silver nanoparticles, nanotubes, prevention of infection.
- MeSH
- antibakteriální látky * MeSH
- biokompatibilní potahované materiály MeSH
- kovové nanočástice * MeSH
- lidé MeSH
- nanotrubičky * MeSH
- stříbro MeSH
- titan MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Texture analysis is an established technique to assess objectively the textural properties of materials and products, such as hardness, elasticity, burst strength and adhesiveness. With the need for reliable and cost-effective equipment, texture analysis is becoming the method of choice in the pharmaceutical industry to maintain quality standards and provide analytical data on multiple products such as pharmaceutical dosage forms. With the large number of techniques and probes available to assess physical properties of materials, texture analyzers represent innovative equipment for research and industrial purposes.
- Klíčová slova
- textura, texturometr, texturní analýza, mechanické vlastnosti, mukoadhezivní lékové formy,
- MeSH
- čípky MeSH
- kontrola léčiv a omamných látek metody MeSH
- lékové formy * MeSH
- masti MeSH
- obvazy MeSH
- povrchové vlastnosti MeSH
- prášky, zásypy, pudry MeSH
- tablety MeSH
- testování materiálů MeSH
- tobolky MeSH
- zdravotnické prostředky MeSH
- Publikační typ
- přehledy MeSH
A lot of insect families have physical structures created by evolution for coloration. These structures are a source of ideas for new bio-inspired materials. The aim of this study was to quantitatively characterize the micromorphology of butterfly wings scales using atomic force microscopy and multifractal analysis. Two types of butterflies, Euploea mulciber ("striped blue crow") and Morpho didius ("giant blue morpho"), were studied. The three-dimensional (3D) surface texture of the butterfly wings scales was investigated focusing on two areas: where the perceived colors strongly depend on and where they do not depend on the viewing angle. The results highlight a correlation between the surface coloration and 3D surface microtexture of butterfly wings scales.
- MeSH
- biologické modely MeSH
- fraktály MeSH
- křídla zvířecí ultrastruktura MeSH
- matematické pojmy MeSH
- mikroskopie atomárních sil MeSH
- motýli ultrastruktura MeSH
- nanostruktury ultrastruktura MeSH
- pigmentace MeSH
- povrchové vlastnosti MeSH
- zobrazování trojrozměrné MeSH
- zvířata MeSH
- zvířecí šupiny ultrastruktura MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
UNLABELLED: PURPOSE OF THE STUDY The alloplastic materials currently used for protective surface layers on implants were tested in vitro under microbiological laboratory conditions by contamination with microbial agents most frequently found in deep infection of total joint replacements. The objective was to find out how the resistance to bacterial colonisation was related to different surface finishes. MATERIAL AND METHODS Each of 14 samples of alloplastic material currently used in the manufacture of orthopaedic implants was inoculated with each of the group of microorganisms most frequently infecting joint replacements; these were Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Enterococcus faecalis and Escherichia coli. At 24 hours of incubation, biofilms produced on sample surfaces were collected, stained with crystalline violet and assessed by spectrophotometry. The average value of biofilm absorbances (AV595) for the group of microorganism tested was taken as a basic characteristic of each material sample indicating its sensitivity to bacterial. RESULTS Of the metal materials with smooth surface finish, Vitalium (AV595, 0.368) showed the lowest affinity to microbial colonisation; next was titanium (AV595, 0.459) and steel (AV595, 0.505). A significant increase in sensitivity to bacterial colonisation was recorded in all types of surface finish of steel (AV595, 0.571) and in titanium alloy with a rough surface texture (AV595, 0.737 to 1.676); p < 0.05. Porous titanium surfaces significantly increased material affinity to colonisation. DISCUSSION Our study had certain limitations concerning in vitro evaluation of porous surfaces that have high affinity to bacterial colonisation. Porous titanium, and its hydroxyapatite layer in particular, considerably promotes osteoblast colonisation of the surface as well as implant osseointegration in the bone bed. Microorganisms therefore have no room for surface colonisation. Problematic may remain the surface parts outside contact with bone that keep their affinity to bacterial colonisation. CONCLUSIONS The material of choice for cemented implants is Vitalium which, of all metal surfaces, has the lowest sensitivity to bacterial colonisation. The materials of choice for cementless implants are titanium alloys. However, an osteoactive surface not in contact with bone remains a problem. On the one hand, its roughness and porosity are crucial to good osseointegration, on the other hand, its affinity to bacterial colonisation is high. KEY WORDS: alloplastic material, biofilm, joint replacement infection.
- MeSH
- artroplastiky kloubů přístrojové vybavení MeSH
- biofilmy růst a vývoj MeSH
- biokompatibilní materiály škodlivé účinky chemie MeSH
- Enterococcus faecalis fyziologie MeSH
- Escherichia coli fyziologie MeSH
- infekce spojené s protézou mikrobiologie MeSH
- lidé MeSH
- povrchové vlastnosti MeSH
- protézy a implantáty škodlivé účinky MeSH
- Pseudomonas aeruginosa fyziologie MeSH
- Staphylococcus aureus fyziologie MeSH
- Staphylococcus epidermidis fyziologie MeSH
- testování materiálů MeSH
- titan chemie MeSH
- vitalium chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
