AFM Study of Untreated and Treated Fibers of Mongolian Goat Cashmere

2009 ◽  
Vol 610-613 ◽  
pp. 175-178 ◽  
Author(s):  
Namsrai Javkhlantugs ◽  
Enkhbaatar Ankhbayar ◽  
Khishigjargal Tegshjargal ◽  
Damdin Enkhjargal ◽  
Chimed Ganzorig

The morphological surface change of untreated and treated fibers of the Mongolian goat cashmere was investigated by atomic force microscopy (AFM) at ambient conditions. The cuticle scale heights of the Mongolian goat cashmere fibers were measured by the AFM for the fibers before and after treatment. The experimental results showed that the difference between the fine structure of the cuticle and surface roughness of untreated and treated fibers. We found that the surface morphological change of the cashmere fibers was strongly degraded after the bleaching process.

1996 ◽  
Vol 448 ◽  
Author(s):  
Woochul Yang ◽  
F.J. Jedema ◽  
H. Ade ◽  
R.J Nemanich

AbstractThe morphologies of nanoscale epitaxial islands of TISi2 are studied. The islands are prepared by deposition of ultrathin Ti (3-20Å) on both smooth and roughened.Si(001) substrates. The island formation is initiated by annealing to 800-1000°C. The roughened substrates are prepared by etching with atomic H produced in a plasma. The morphologies of the substrate before and after island formation are examined by atomic force microscopy (AFM). In particular, the influence of surface-roughness on both the formation of islands and the size distribution of islands is investigated. On a rough substrate islands with a lateral dimension of ~350Å and a vertical dimension of ~25Å were observed with size uniformity of ~20%. Also it was observed that the roughness of the surface reduced the island size and affected the island distribution. The results are discussed in terms of surface energy and the strain field around the islands.


2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Frederico dos Reis Goyatá ◽  
Sávio Morato de Lacerda Gontijo ◽  
José Alcides Almeida de Arruda ◽  
João Batista Novaes Júnior ◽  
Ivan Doche Barreiros ◽  
...  

The aim of the present report was to describe a case of direct composite resin restoration in tooth 46, with emphasis on the importance of polishing. A 21-year-old female patient dissatisfied with the aesthetic amalgam restoration of her tooth 46 came to the our institution for correction of the situation. The procedure performed consisted of registration of occlusal contacts, selection of resin color, removal of amalgam restoration, coronal reconstruction with composite resin, occlusal adjustment, finishing and polishing, with the use of atomic force microscopy of the resin before and after polishing. A correct clinical protocol for the posterior composite resins is fundamental for the optimization of aesthetic results, for clinical performance and for consequent restorative longevity. The atomic force microscopy images of the resin used before and after polishing emphasize the necessity and clinical importance of this operative step.Descriptors: Dental Materials; Dental Restoration, Permanent; Dental Polishing; Microscopy.ReferencesFrese C, Staehle HJ, Wolff D. The assessment of dentofacial esthetics in restorative dentistry: a review of the literature. J Am Dent Assoc. 2012;143(5):461-66.Moraschini V, Fai CK, Alto RM, dos Santos GO. Amalgam and resin composite longevity of posterior restorations: A systematic review and meta-analysis. J Dent. 2015;43(9):1043-50.Kovarik RE. Restoration of posterior teeth in clinical practice: evidence base for choosing amalgam versus composite. Dent Clin North Am. 2009;53(1):71-6.Kanzow P, Wiegand A, Schwendicke F. Cost-effectiveness of repairing versus replacing composite or amalgam restorations. J Dent. 2016;54:41-7.Lynch CD, Opdam NJ, Hickel R, Brunton PA, Gurgan S, Kakaboura A, et al. Guidance on posterior resin composites: Academy of Operative Dentistry - European Section. J Dent. 2014;42(4):377-83.Fernández E, Martín J, Vildósola P, Oliveira Junior OB, Gordan V, Mjor I et al. Can repair increase the longevity of composite resins? Results of a 10-year clinical trial. J Dent. 2015;43(2):279-86.Sabbagh J, McConnell RJ, McConnell MC. Posterior composites: Update on cavities and filling techniques. J Dent. 2017;57:86-90.Constantinescu DM, Apostol DA, Picu CR, Krawczyk K, Sieberer M. Mechanical properties of epoxy nanocomposites reinforced with functionalized silica nanoparticles. Proc Struct Integ. 2017;5:647-52.Yadav RD, Raisingani D, Jindal D, Mathur R. A comparative analysis of different finishing and polishing devices on nanofilled, microfilled, and hybrid composite: a scanning electron microscopy and profilometric study. Int J Clin Pediatr Dent. 2016;9(3):201-8.Fernandes ACBCJ, Assunção IV, Borges BCD, Costa GFA. Impact of additional polishing on the roughness and surface morphology of dental composite resins. Rev Port Estomatol Med Dent Cirur Maxilofac. 2016;57(2):74-81.Antonson SA, Yazici AR, Kilinc E, Antonson DE, Hardigan PC. Comparison of different finishing/polishing systems on surface roughness and gloss of resin composites. J Dent. 2011;39(Suppl 1):e9-17.Kumari CM, Bhat KM, Bansal R. Evaluation of surface roughness of different restorative composites after polishing using atomic force microscopy. J Conserv Dent. 2016;19(1):56-62.Pimentel PEZ, Goyatá FR, Cunha LG. Influência da técnica de polimento na lisura superficial de resinas compostas. Clin int j braz dent. 2012;8(2):226-34.Chour RG, Moda A, Arora A, Arafath MY, Shetty VK, Rishal Y. Comparative evaluation of effect of different polishing systems on surface roughness of composite resin: An in vitro study. J Int Soc Prev Community Dent. 2016;6(Suppl 2):166-70.Lins FC, Ferreira RC, Silveira RR, Pereira CN, Moreira AN, Magalhaes CS. Surface roughness, microhardness, and microleakage of a silorane-based composite resin after immediate or delayed finishing/polishing. Int J Dent. 2016;2016:8346782.


2001 ◽  
Vol 81 (3) ◽  
pp. 337-348 ◽  
Author(s):  
C. Liu ◽  
A I Frenkel ◽  
A. Vairavamurthy ◽  
P M Huang

Humic acids (HA) constitute a major fraction of the organic matter in soils and sediments. Little is known about the kinetics and mechanisms of Cd sorption by HAs, especially those pertaining to the surface features and structure of the Cd-humate complexes. We investigated Cd sorption by HA using the conventional batch method, N2-BET method, atomic force microscopy (AFM), and extended X-ray absorption fine structure (EXAFS) spectroscopy to gain a better understanding of the kinetics and mechanisms. Cadmium sorption by HA can be described by the parabolic diffusion equation. The increase in the apparent diffusion coefficient with an increase in the initial Cd concentration was less pronounced at higher initial Cd concentrations, apparently due to an enhancement in aggregation of the Cd-humate complexes. The HA before and after Cd sorption at Cd concentrations ≤ 10–6 M in different reaction times was spheroidal in shape. The Cd-humate complexes formed at 10–4 and 10–3 M Cd gradually changed to resemble the shape of a bean with increasing reaction time, thereby substantially decreasing their specific surface. Cadmium ions raveled the spheroidal HA particles into a bean-like structure by coordinating to six O atoms from the functional groups of HA, with a Cd-O distance of 2.297(2) Å. The Cd-O bond strength decreased with increasing initial Cd concentration. Key words: Cadmium, humate complexes, conformation, atomic force microscopy, EXAFS


2021 ◽  
Vol 5 (1) ◽  
pp. 19-23
Author(s):  
Syahrial , ◽  
Pocut Aya Sofya ◽  
Adellya Tasya Sukma

The surface of heat-cured acrylic resin on the base of artificial teeth has a risk of surface roughness. Its causes are liquid absorption and chemical processes. Fluid absorption can be affected by immersion in denture cleaners containing sodium bicarbonate. This study aims to determine the effect of a denture cleanser containing 48% sodium bicarbonate on changes in heat-cured acrylic resin's roughness. This study used 16 specimens of heat-cured acrylic resin (brand Meliodent) and was square in size of 10x10x2.0 ± 0.5 mm. The samples' roughness is measured by using Atomic Force Microscopy (AFM). The specimens were immersed in denture cleansing tablets containing 48% sodium bicarbonate for 17 days at room temperature ± 25 °C and were replaced within 8 hours. After immersion, the specimens were measured again using Atomic Force Microscopy (AFM) to determine the final roughness. The data obtained were analyzed by using paired t-test. The analysis showed no significant difference between surface roughness before and after soaking with a denture cleansing tablet containing 48% sodium bicarbonate (p 0.05). This study concluded that there was no increase in the roughness of heat-cured acrylic resin after immersion in denture cleansing tablets containing 48% sodium bicarbonateKEYWORDS: Fittydent, heat-cured acrylic resin, surface roughness


2021 ◽  
Vol 6 (1) ◽  
pp. 12-17
Author(s):  
Viona DIANSARI ◽  
Diana Setya NINGSIH ◽  
Hafra AMINI

ABSTRACT Nano-filled composite resin is a composite resin that has nano-sized fillers. This filler sizegives an aesthetic appearance to the composite resin thus resembles natural teeth. However, compositeresin has a disadvantage in its polymer matrix, which is easily degraded by acid solutions. Calamansiorange (Citrus microcarpa) is a solution that has acidic properties. The purpose of this research was todetermine the surface roughness value of nanofiller composite resin after immersed in a 50%concentration of calamansi orange (Citrus microcarpa). Ten cylindrical specimens of nano-filled compositeresin (Filtex Z350 XT 3M ESPE), with 5 mm diameter and 2 mm thickness. The specimens wereimmersed for 14 days with the provisions of 5 minutes in the juice of calamansi orange and 23 hours 55minutes in distilled water. Calamansi orange juice is replaced every day. The evaluation of surfaceroughness of specimens before and after immersion using Atomic Force Microscopy (AFM).Furthermore, the data were analyzed using paired t-test with a significant value is p 0.05. The resultsshowed an increase in the average value of surface roughness which was significant after exposure inthe calamansi orange with 50% concentration. KEYWORDS: Atomic Force Microscopy, Citrus microcarpa), surface roughness, .nanofilled composite


Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.


2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>


2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Juan Gros-Otero ◽  
Samira Ketabi ◽  
Rafael Cañones-Zafra ◽  
Montserrat Garcia-Gonzalez ◽  
Cesar Villa-Collar ◽  
...  

Abstract Background To compare the anterior surface roughness of two commercially available posterior chamber phakic intraocular lenses (IOLs) using atomic force microscopy (AFM). Methods Four phakic IOLs were used for this prospective, experimental study: two Visian ICL EVO+ V5 lenses and two iPCL 2.0 lenses. All of them were brand new, were not previously implanted in humans, were monofocal and had a dioptric power of − 12 diopters (D). The anterior surface roughness was assessed using a JPK NanoWizard II® atomic force microscope in contact mode immersed in liquid. Olympus OMCL-RC800PSA commercial silicon nitride cantilever tips were used. Anterior surface roughness measurements were made in 7 areas of 10 × 10 μm at 512 × 512 point resolution. The roughness was measured using the root-mean-square (RMS) value within the given regions. Results The mean of all anterior surface roughness measurements was 6.09 ± 1.33 nm (nm) in the Visian ICL EVO+ V5 and 3.49 ± 0.41 nm in the iPCL 2.0 (p = 0.001). Conclusion In the current study, we found a statistically significant smoother anterior surface in the iPCL 2.0 phakic intraocular lenses compared with the VISIAN ICL EVO+ V5 lenses when studied with atomic force microscopy.


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