Synthetic Biomimetic Carbonate-Hydroxyapatite Nanocrystals for Enamel Remineralization

2008 ◽  
Vol 47-50 ◽  
pp. 821-824 ◽  
Author(s):  
Norberto Roveri ◽  
Elisa Battistella ◽  
Ismaela Foltran ◽  
Elisabetta Foresti ◽  
Michele Iafisco ◽  
...  
Keyword(s):  
Physical Properties ◽  
Experimental Results ◽  
Carbonate Hydroxyapatite ◽  
Mineral Deposition ◽  
Enamel Structure ◽  
Synthetic Coating ◽  
Composition Structure ◽  
Hydroxyapatite Nanocrystals ◽  
Bone Apatite ◽  
Natural Apatite

New biomimetic carbonate-hydroxyapatite nanocrystals (CHA) have been designed and synthesized in order to obtain a remineralization of the altered enamel surfaces. Synthesized CHA mimic for composition, structure, nano dimension and morphology bone apatite crystals and their chemical-physical properties resemble closely those exhibited by enamel natural apatite. CHA can chemically bound themselves on the surface of natural enamel apatite thanks to their tailored biomimetic characteristics. The remineralization effect induced by CHA represents a real new deposition of carbonate-hydroxyapatite into the eroded enamel surface scratches forming a persistent biomimetic mineral coating, which covers and safeguards the enamel structure. The experimental results point out the possibility to use materials alternative to fluoride compounds which is commonly utilized to contrast the mechanical abrasions and acid attacks. The apatitic synthetic coating is less crystalline than enamel natural apatite, but consists of a new biomimetic apatitic mineral deposition which progressively fills the surface scratches. Therefore the application of biomimetic CHA may be considered an innovative approach to contrast the acid and bacteria attacks.

scholarly journals Surface Enamel Remineralization: Biomimetic Apatite Nanocrystals and Fluoride Ions Different Effects

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Norberto Roveri ◽  
Elisa Battistella ◽  
Claudia Letizia Bianchi ◽  
Ismaela Foltran ◽  
Elisabetta Foresti ◽  
...  
Keyword(s):  
Tooth Enamel ◽  
Acid Resistance ◽  
Enamel Surface ◽  
Fluoride Ions ◽  
Crystallinity Degree ◽  
Carbonate Hydroxyapatite ◽  
Apatite Crystals ◽  
Biomimetic Apatite ◽  
Enamel Structure ◽  
Hydroxyapatite Nanocrystals

A new method for altered enamel surface remineralization has been proposed. To this aim carbonate-hydroxyapatite nanocrystals which mimic for composition, structure, nanodimensions, and morphology dentine apatite crystals and resemble closely natural apatite chemical-physical properties have been used. The results underline the differences induced by the use of fluoride ions and hydroxyapatite nanocrystals in contrasting the mechanical abrasions and acid attacks to which tooth enamel is exposed. Fluoride ions generate a surface modification of the natural enamel apatite crystals increasing their crystallinity degree and relative mechanical and acid resistance. On the other hand, the remineralization produced by carbonate-hydroxyapatite consists in a deposition of a new apatitic mineral into the eroded enamel surface scratches. A new biomimetic mineral coating, which progressively fills and shadows surface scratches, covers and safeguards the enamel structure by contrasting the acid and bacteria attacks.

Relation between Molecular Weights and Physical Properties of Rubber Fractions

1941 ◽  
Vol 14 (3) ◽  
pp. 580-589 ◽  
Author(s):  
G. Gee ◽  
L. R. G. Treloar
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Physical Properties ◽  
High Molecular Weight ◽  
Elastic Properties ◽  
Elastic Material ◽  
Experimental Results ◽  
Molecular Weights ◽  
High Elasticity ◽  
Latex Rubber

Abstract As high elasticity is a property possessed only by substances of high molecular weight, it is of interest to enquire into the relation between the elastic properties of a highly elastic material such as rubber and its molecular weight. An investigation on these lines has been made possible through the work of Bloomfield and Farmer, who have succeeded in separating natural rubber into fractions having different average molecular weights. The more important physical properties of these fractions have been examined with the object of determining which of the properties are dependent on molecular weight and which are not. Fairly extensive observations were made on the fractions from latex rubber referred to as Nos. 2, 3 and 4 by Bloomfield and Farmer, and some less extensive observations were carried out on the less oxygenated portion of fraction No. 1 obtained from crepe rubber (called hereafter 1b) . Before considering these experimental results, and their relation to the molecular weights of the fractions, it will be necessary to refer briefly to the methods used for the molecular-weight determinations, and to discuss the significance of the figures obtained.

A Comprehensive Understanding on Sewability of Natural Biomaterial: An Insight on Process Optimization during Leather Manufacture

2021 ◽  
Vol 116 (7) ◽  
Author(s):  
Gladstone Christopher Jayakumar ◽  
K Phebe Aaron ◽  
K Krishnaraj
Keyword(s):  
Physical Properties ◽  
Process Optimization ◽  
Three Dimensional ◽  
Experimental Results ◽  
Comprehensive Understanding ◽  
Microscopic Images ◽  
Dimensional Matrix ◽  
Natural Biomaterial ◽  
Leather Manufacture

Leather is three-dimensional matrix possessing unique properties which makes it more comfortable for daily use. Garments made from leathers are preferred choice owing to their multifaceted properties as compared to textiles in the colder regions. In the present study, an attempt has been made to evaluate the influence of phenolic syntan and synthetic fatliquor on the sewability and physical properties of post tanned leathers. From the experimental results, it is observed that the concentration of phenolic syntan and fatliquor influences leather sewability. Optical microscopic images of leathers also show that they are more compact and tighter with higher percentage of syntan. The study provides an insight in understanding the optimum usage of post tanning chemicals for better sewing properties without affecting the leather matrix adversely.

The Remineralizing Effect of Carbonate-Hydroxyapatite Nanocrystals on Dentine

2007 ◽  
pp. 602-605
Author(s):  
Lia Rimondini ◽  
Barbara Palazzo ◽  
Michele Iafisco ◽  
Lorenza Canegallo ◽  
Federica Demarosi ◽  
...  
Keyword(s):  
Carbonate Hydroxyapatite ◽  
Hydroxyapatite Nanocrystals

scholarly journals ESTUDO COMPARATIVO ENTRE O FIO DE NAILON E A LINHA DE PESCA (POLIAMIDA) E A SUA APLICABILIDADE COMO FIO CIRÚRGICO

1999 ◽  
Vol 4 (1) ◽  
Author(s):  
SHEILA CANEVESE RAHAL ◽  
MANOEL ÁLVARO GUIMARÃES ◽  
JOSÉ VICENTE FORTES ◽  
HÉLIO LANGONI ◽  
PEDRO HELIO LUCCHIARI
Keyword(s):  
Adverse Effect ◽  
Comparative Study ◽  
Physical Properties ◽  
Group Iv ◽  
Experimental Results ◽  
Control Group ◽  
Group Iii ◽  
Nylon Thread ◽  
Group I ◽  
Mucous Membranes

"Linhas de pesca"* em diâmetros de 0,15mm; 0,20mm; 0,25mm; 0,30mm foram divididas em quatro grupos, contendo dez amostras de cada diâmetro: grupo I - controle; grupo II - linhas colocadas em frasco com pastilhas de formalina; grupo III - um ciclo de autoclavagem (30 minutos à 121 C, seguido por 10 minutos de secagem à 37 C em estufa); grupo IV - dois ciclos de autoclavagens. Foram avaliadas quanto: comprimento, calibre, resistência no nó e alongamento. Comparativamente foram examinados fios de náilon cirúrgico nas numerações 0, 1-0, 2-0, 3-0, 4-0 e 5-0 (10 amostras de cada um). Pelos resultados da análise estastística, verificou-se que a esterilização pelo calor úmido exerceu um efeito adverso na resistência da "linha de pesca". Por outro lado não houve diferenças na resistência, calibre e alongamento da "linha de pesca" entre o primeiro e segundo ciclo de autoclavagem. As “linhas” mantidas em pastilhas de formalina mantiveram na sua maioria suas características originais de resistência, comprimento, diâmetro e alongamento quando comparada ao grupo controle, entretanto, cabe lembrar que o formaldeído é considerado irritante para pele e membrana mucosa. Foi possível concluir que a "linha de pesca" apresenta características semelhantes ao fio cirúrgico, podendo ser mantida em pastilhas de formalina ou esterilizada em autoclave, lembrando que a autoclavagem altera algumas de suas propriedades físicas. Abstract A comparative study has been carried out between fishing lines and nylon thread in regard to their applicability as surgical thread. Four groups of 10 fishing lines in each of the following diameters = 0.15, 0.20, 0.25 and 0.30 mm = were subjected to the following treatments: group I, control; group II sterilized with formalin tablets; group III, autoclaved 30 minutes at 121oC; group IV, autoclaved twice 30 minutes at 121oC. The following parameters were then considered: length, caliber, resistance at the knot, and elongation. Ten samples of each surgical 0, 1.0, 2.0, 3.0, 4.0 and 5.0 nylon threads were used in comparatively similar experiments as the ones carried out with the fishing lines. According to the statistical analyses of the experimental results, it has been found that the sterilization by means of the humid heat exerts an adverse effect on the resistance of the fishing line. However, no differences were found between the effect displayed by two cycles sterilization compared with the fishing lines subjected to only one cycle. The threads maintained in formalin kept the majority of their original properties of resistance, length, diameter and elongation when compared with the control group. It is known, however that formaldehyde is an irritant chemical towards the skin and the mucous membranes. It was possible to conclude: a. fishing lines display characteristics similar to that ones of the nylon surgical thread; b. they can be maintained in formalin solution; c. autoclave sterilization alters some of their physical properties.

Advanced Thermoelectric Materials and Systems for Automotive Applications in the Next Millennium

1997 ◽  
Vol 478 ◽  
Author(s):  
Donald T. Morelli
Keyword(s):  
Environmental Economic ◽  
Physical Properties ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Experimental Results ◽  
Automotive Applications ◽  
New Materials ◽  
Thermoelectric Devices ◽  
Filled Skutterudites ◽  
Fundamental Physical

AbstractA combination of environmental, economic, and technological drivers has led to a reassessment of the potential for using thermoelectric devices in several automotive applications. In order for this technology to achieve its ultimate potential, new materials with enhanced thermoelectric properties are required. Experimental results on the fundamental physical properties of some new thermoelectric materials, including filled skutterudites and 1–1–1 intermetallic semiconductors, are presented.

Effect of the Surfactant Concentration on Sinking Electric Discharge Machining Performance with Water-in-Oil Emulsion as Dielectric

2011 ◽  
Vol 189-193 ◽  
pp. 3153-3157
Author(s):  
Yan Zhen Zhang ◽  
Yong Hong Liu ◽  
Ren Jie Ji ◽  
Bao Ping Cai
Keyword(s):  
Physical Properties ◽  
Electric Discharge ◽  
Surfactant Concentration ◽  
Emulsion Stability ◽  
Experimental Results ◽  
Machining Performance ◽  
Electric Discharge Machining ◽  
Oil Emulsion ◽  
The Stability ◽  
Water In Oil Emulsion

In this paper, the EDM performance of water-in-oil (W/O) emulsions dielectric with different surfactant concentration is investigated by correlated to its physical properties, such as viscosity and droplets size, which is predominantly determined by the surfactant concentration. Experimental results show that the stability of the W/O emulsions increases with increasing surfactant concentration, whereas the EDM performance deteriorates with increasing surfactant concentration. So, taking a comprehensively consideration of the emulsion stability and EDM performance, the concentration of surfactant must be appropriately selected.

scholarly journals A Basic Study on Establishing the Automatic Sewing Process According to Textile Properties

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1206
Author(s):  
Suhyun Lee ◽  
Soohyeon Rho ◽  
Daeyoung Lim ◽  
Wonyoung Jeong
Keyword(s):  
Surface Roughness ◽  
Physical Properties ◽  
Regression Equation ◽  
Experimental Results ◽  
The Other ◽  
Feeding System ◽  
Basic Study ◽  
Sewing Machine ◽  
Stitch Length ◽  
Smart Factories

This study aimed to establish an automatic sewing process for garment production according to textile properties. An automatic feeding system and a self-made template were introduced to an industrial sewing machine. Two types of stitches were performed on fabrics with various physical properties and surface roughness using this automatic sewing machine. The appearance, stitch length and width, seam strength, and seam efficiency were evaluated according to the sewing conditions, such as presser height and sewing speed. In addition, the correlation between textile properties, sewing conditions, and sewability was analyzed to derive a regression equation for sewability. The evaluation showed no difference in the lock stitch condition. On the other hand, under the zigzag stitch condition, the stitch width differed according to the presser height, which also affected the seam structure. The optimal presser height for each fabric was derived from the experimental results. In terms of the sewing speed, however, the seam strength was the best at 200 RPM in the lock stitch and 400 RPM in the zigzag stitch. The moderating effect of the presser height between textile properties and sewability in the lock stitch condition was confirmed. This result can be used as basic data for establishing an automatic sewing process for smart factories.

scholarly journals Physical properties of waxy rice starch gel with Chew-Kuk (Gnaphalium polycaulon)

2020 ◽  
Vol 187 ◽  
pp. 04010
Author(s):  
Jittimon Wongsa ◽  
Sawanit Aichayawanich
Keyword(s):  
Physical Properties ◽  
Sensory Evaluation ◽  
Experimental Results ◽  
Rice Starch ◽  
Yellowish Green ◽  
Starch Gel ◽  
Waxy Rice ◽  
Waxy Rice Starch

This research aimed to study effects of Chew-Kuk on physical properties of waxy rice starch gel. Sensory evaluation, color and textural profiles were determining criteria used to evaluate the waxy rice starch gel with added Chew-Kuk. The experimental results show that Chew-Kuk significantly affects color and texture of the waxy rice starch gel. Upon adding Chew-Kuk, waxy rice starch gel became yellowish green. Hardness, gumminess, and chewiness values of waxy rice starch gel with Chew-Kuk were decreased when Chew-Kuk: waxy rice starch ratios increased. Moreover, liking scores tended to be higher when adding more Chew-Kuk contents. Therefore, the suitable ratio between Chew-Kuk and waxy rice starch in this research is the highest ratio (Chew-Kuk: waxy rice starch equal to 20: 100).

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