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Sample records for artificial demineralized surface

  1. In vitro study of the diode laser effect on artificial demineralized surface of human dental enamel

    International Nuclear Information System (INIS)

    In scientific literature there are many reports about fusion and resolidification of dental enamel after laser irradiation and their capability to generate surfaces with increased resistance to demineralization compared to non-irradiated areas. The use of high power diode laser on demineralized surfaces of human dental enamel is presented as a good alternative in caries prevention. The purpose of this study is to investigate the morphological changes produced by the use of one high power diode laser on human dental enamel surface after demineralization treatment with lactic acid, under chosen parameters. Fifteen samples of human dental molars were used and divided in four groups: control - demineralization treatment with lactic acid and no irradiation, and demineralization treatment with lactic acid followed of irradiation with 212,20 mJ/cm2, 282,84 mJ/cm2 and 325,38 mJ/cm2, respectively. The samples were irradiated with high power diode laser (808 nm) with a 300 μm diameter fiber optics. Black ink was used on enamel surface to enhance the superficial absorption. The samples were studied by optical microscopy and scanning electron microscopy. Modifications on the enamel surfaces were observed. Such modifications were characterized by melted and re-solidified region of the enamel. According with our results the best parameter was 2.0 W, presenting the most uniform surface. The use of high power diode laser as demonstrated in this study is able to promote melting and re-solidification on human dental enamel. (author)

  2. Combining CPP-ACP with fluoride: a synergistic remineralization potential of artificially demineralized enamel or not?

    Science.gov (United States)

    El-Sayad, I. I.; Sakr, A. K.; Badr, Y. A.

    2008-08-01

    Background and objective: Minimal intervention dentistry (MID) calls for early detection and remineralization of initial demineralization. Laser fluorescence is efficient in detecting changes in mineral tooth content. Recaldent is a product of casein phosphopeptide-amorphous calcium phosphate (CPP- ACP) which delivers calcium and phosphate ions to enamel. A new product which also contains fluoride is launched in United States. The remineralizing potential of CPP- ACP per se, or when combined with 0.22% Fl supplied in an oral care gel on artificially demineralised enamel using laser fluorescence was investigated. Methods: Fifteen sound human molars were selected. Mesial surfaces were tested using He-Cd laser beam at 441.5nm with 18mW power as excitation source on a suitable set-up based on Spex 750 M monochromator provided with PMT for detection of collected auto-fluorescence from sound enamel. Mesial surfaces were subjected to demineralization for ten days. The spectra from demineralized enamel were measured. Teeth were then divided according to the remineralizing regimen into three groups: group I recaldent per se, group II recaldent combined with fluoride gel and group III artificial saliva as a positive control. After following these protocols for three weeks, the spectra from remineralized enamel from the three groups were measured. The spectra of enamel auto-fluorescence were recorded and normalized to peak intensity at about 540 nm to compare between spectra from sound, demineralized and remineralized enamel surfaces. Results: A slight red shift was noticed in spectra from demineralized enamel, while a blue shift may occur in remineralized enamel. Group II showed the highest remineralizing potential. Conclusions: Combining fluoride with CPP-ACP had a synergistic effect on enamel remineralization. In addition, laser auto-fluorescence is an accurate technique for assessment of changes in tooth enamel minerals.

  3. Combining casein phosphopeptide-amorphous calcium phosphate with fluoride: synergistic remineralization potential of artificially demineralized enamel or not?

    Science.gov (United States)

    Elsayad, Iman; Sakr, Amal; Badr, Yahia

    2009-07-01

    Recaldent is a product of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). The remineralizing potential of CPP-ACP per se, or when combined with 0.22% Fl gel on artificially demineralized enamel using laser florescence, is investigated. Mesial surfaces of 15 sound human molars are tested using a He-Cd laser beam at 441.5 nm with 18-mW power as an excitation source on a suitable setup based on a Spex 750-M monochromator provided with a photomultiplier tube (PMT) for detection of collected autofluorescence from sound enamel. Mesial surfaces are subjected to demineralization for ten days. The spectra from demineralized enamel are measured. Teeth are divided into three groups according to the remineralizing regimen: group 1 Recaldent per se, group 2 Recaldent combined with fluoride gel and ACP, and group 3 artificial saliva as a positive control. After following these protocols for three weeks, the spectra from the remineralized enamel are measured. The spectra of enamel autofluorescence are recorded and normalized to peak intensity at about 540 nm to compare spectra from sound, demineralized, and remineralized enamel surfaces. A slight red shift occurred in spectra from demineralized enamel, while a blue shift may occur in remineralized enamel. Group 2 shows the highest remineralizing potential. Combining fluoride and ACP with CPP-ACP can give a synergistic effect on enamel remineralization.

  4. In vitro study of the diode laser effect on artificial demineralized surface of human dental enamel; Estudo in vitro do efeito do laser diodo sobre a superficie de esmalte dental humano desmineralizado artificialmente

    Energy Technology Data Exchange (ETDEWEB)

    Ebel, Patricia

    2003-07-01

    In scientific literature there are many reports about fusion and resolidification of dental enamel after laser irradiation and their capability to generate surfaces with increased resistance to demineralization compared to non-irradiated areas. The use of high power diode laser on demineralized surfaces of human dental enamel is presented as a good alternative in caries prevention. The purpose of this study is to investigate the morphological changes produced by the use of one high power diode laser on human dental enamel surface after demineralization treatment with lactic acid, under chosen parameters. Fifteen samples of human dental molars were used and divided in four groups: control - demineralization treatment with lactic acid and no irradiation, and demineralization treatment with lactic acid followed of irradiation with 212,20 mJ/cm{sup 2}, 282,84 mJ/cm{sup 2} and 325,38 mJ/cm{sup 2}, respectively. The samples were irradiated with high power diode laser (808 nm) with a 300 {mu}m diameter fiber optics. Black ink was used on enamel surface to enhance the superficial absorption. The samples were studied by optical microscopy and scanning electron microscopy. Modifications on the enamel surfaces were observed. Such modifications were characterized by melted and re-solidified region of the enamel. According with our results the best parameter was 2.0 W, presenting the most uniform surface. The use of high power diode laser as demonstrated in this study is able to promote melting and re-solidification on human dental enamel. (author)

  5. Comparative evaluation of remineralizing potential of three agents on artificially demineralized human enamel: An in vitro study

    Directory of Open Access Journals (Sweden)

    Namrata Patil

    2013-01-01

    Full Text Available Introduction: Remineralization as a treatment procedure has received much attention from clinicians. The objective of this in vitro study was to find out the efficacy of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP, casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF, and tricalcium phosphate fluoride (TCP-F in remineralizing enamel surface on which artificial caries lesion had been created. The changes were analyzed using DIAGNOdent® (KaVo and scanning electron microscope (SEM. Materials and Methods: A total of 52 premolars and 24 molars were selected and classified into four groups of 13 premolars and 6 molars in each: I (CPP-ACP, II (CPP-ACPF, III (TCP-F, and IV (artificial saliva. All the samples were assessed using DIAGNOdent at the baseline and after demineralization and remineralization. Ten samples were randomly selected from each group baseline after demineralization and after remineralization for surface evaluation using SEM. Results: Statistical analysis showed that all the experimental groups had a significantly higher amount of remineralization except for group IV. Conclusion: All the three experimental groups showed a statistically significant amount of remineralization. However, because of the added benefit of fluoride (NaF 0.2%, CPP-ACPF (Tooth Mousse-Plus® and TCP-F showed marginally more amount of remineralization than did CPP-ACP (Tooth Mousse® . Remineralization efficacy was TCP-F > CPP-ACPF > CPP-ACP.

  6. Comparative evaluation of remineralizing potential of three agents on artificially demineralized human enamel: An in vitro study

    Science.gov (United States)

    Patil, Namrata; Choudhari, Shantanu; Kulkarni, Sadanand; Joshi, Saurabh R

    2013-01-01

    Introduction: Remineralization as a treatment procedure has received much attention from clinicians. The objective of this in vitro study was to find out the efficacy of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF), and tricalcium phosphate fluoride (TCP-F) in remineralizing enamel surface on which artificial caries lesion had been created. The changes were analyzed using DIAGNOdent® (KaVo) and scanning electron microscope (SEM). Materials and Methods: A total of 52 premolars and 24 molars were selected and classified into four groups of 13 premolars and 6 molars in each: I (CPP-ACP), II (CPP-ACPF), III (TCP-F), and IV (artificial saliva). All the samples were assessed using DIAGNOdent at the baseline and after demineralization and remineralization. Ten samples were randomly selected from each group baseline after demineralization and after remineralization for surface evaluation using SEM. Results: Statistical analysis showed that all the experimental groups had a significantly higher amount of remineralization except for group IV. Conclusion: All the three experimental groups showed a statistically significant amount of remineralization. However, because of the added benefit of fluoride (NaF 0.2%), CPP-ACPF (Tooth Mousse-Plus®) and TCP-F showed marginally more amount of remineralization than did CPP-ACP (Tooth Mousse®). Remineralization efficacy was TCP-F > CPP-ACPF > CPP-ACP. PMID:23716961

  7. Remineralization of root surfaces demineralized in solutions of differing fluoride levels.

    Science.gov (United States)

    Heilman, J R; Jordan, T H; Warwick, R; Wefel, J S

    1997-01-01

    The beneficial effects of fluoride on enamel have been well documented. However, limited data are available concerning the amount of fluoride required for beneficial effects on tooth root. Although studies have shown that fluoride inhibits root demineralization, the aim of this study was to investigate the location, extent and amount of remineralization on root dentin substrates after demineralization has occurred. The root surfaces of extracted human teeth were demineralized in a pure chemical buffer containing varying concentrations of sodium fluoride. After this lesion initiation, the same root sections were then placed into a remineralizing solution. The root sections were characterized after demineralization, and again after remineralization, by polarized light microscopy (PLM) and microradiography (MRG). Lesion depths after the demineralization phase were found to be inversely proportional to the fluoride concentration. When fluoride was present, bands or lines within the body of the lesion were observed with PLM and MRG. Using quantitative MRG, variations in mineral content and distribution were recorded. Examination of the root sections after the remineralization phase showed remineralization to have occurred on the remaining mineral and not on organic matrix devoid of mineral. The amount and location of mineral deposition may be of great significance in the arrestment and treatment of in vivo root surface caries. PMID:9353581

  8. Near-surface structural examination of human tooth enamel subject to in vitro demineralization and remineralization

    Science.gov (United States)

    Gaines, Carmen Veronica

    The early stages of chemical tooth decay are governed by dynamic processes of demineralization and remineralization of dental enamel that initiates along the surface of the tooth. Conventional diagnostic techniques lack the spatial resolution required to analyze near-surface structural changes in enamel at the submicron level. In this study, slabs of highly-polished, decay-free human enamel were subjected to 0.12M EDTA and buffered lactic acid demineralizing agents and MI Paste(TM) and calcifying (0.1 ppm F) remineralizing treatments in vitro. Grazing incidence x-ray diffraction (GIXD), a technique typically used for thin film analysis, provided depth profiles of crystallinity changes in surface enamel with a resolution better than 100 nm. In conjunction with nanoindentation, a technique gaining acceptance as a means of examining the mechanical properties of sound enamel, these results were corroborated with well-established microscopy and Raman techniques to assess the nanohardness, morphologies and chemical nature of treated enamel. Interestingly, the average crystallite size of surface enamel along its c-axis dimension increased by nearly 40% after a 60 min EDTA treatment as detected by GIXD. This result was in direct contrast to the obvious surface degradation observed by microscopic and confocal Raman imaging. A decrease in nanohardness from 4.86 +/- 0.44 GPa to 0.28 +/- 0.10 GPa was observed. Collective results suggest that mineral dissolution characteristics evident on the micron scale may not be fully translated to the nanoscale in assessing the integrity of chemically-modified tooth enamel. While an intuitive decrease in enamel crystallinity was observed with buffered lactic acid-treated samples, demineralization was too slow to adequately quantify the enamel property changes seen. MI Paste(TM) treatment of EDTA-demineralized enamel showed preferential growth along the a-axis direction. Calcifying solution treatments of both demineralized sample types

  9. Evaluation of enamel surface modification using PS-OCT after laser treatment to increase resistance to demineralization

    Science.gov (United States)

    Kim, Jin Wan; Chan, Kenneth H.; Fried, Daniel

    2016-02-01

    At laser intensities below ablation, carbonated hydroxyapatite in enamel is converted into a purer phase hydroxyapatite with increased acid resistance. Previous studies suggested the possibility of achieving the conversion without surface modification. This study attempts to evaluate the thresholds for the modification without additional changes in physical and optical properties of the enamel. Bovine specimens were irradiated using an RF-excited CO2 laser operating at 9.4-μm with a pulse duration of 26- μs, pulse repetition rates of 100-1000 Hz, with a Gaussian spatial beam profile - 1.4 mm in diameter. After laser treatment, the samples were subjected to acid demineralization for 48 hours to simulate acidic intraoral conditions of a caries attack. The resulting demineralization and erosion were assessed using polarization sensitive OCT (PS-OCT) and 3D digital microscopy. The images from digital microscopy demonstrated a clear delineation between laser protected zones without visual changes and zones with higher levels of demineralization and erosion. Distinct changes in the surface morphology were found within the laser treated area in accordance with the Gaussian spatial beam profile. There was significant protection from the laser in areas that were not visually altered.

  10. Clinical evaluation of demineralization and remineralization of intact root surface lesions in the clinic by a quantitative light-induced fluorescence system.

    Science.gov (United States)

    Durmusoglu, Oykü; Tağtekin, Dilek Arslantunali; Yanikoğlu, Funda

    2012-03-01

    Detection of demineralization of root surface caries is an important issue since preventive approaches prolong tooth life. Quantitative light-induced fluorescence (QLF) has been shown to be useful for the laboratory assessment of demineralization of root surfaces. The aim of this study was to determine the demineralization and remineralization of root surface intact and cavitated caries lesions using a QLF system as a nondestructive in vivo method. Noncavitated and demineralized root surface lesions were detected and scored using the QLF system. Oral hygiene education was given and periodontal cleaning was completed before the remineralization treatment. After obtaining baseline QLF data, the patients were informed about the remineralization treatment. Fluoride varnish was applied to the carious lesions at the baseline visit, and the patients were then reviewed after 1, 2, 3 and 4 weeks, with QLF assessment and fluoride varnish application repeated at each review. Repeated-measures ANOVA (α = 0.05) showed significant differences between ΔQ values at each visit (p Bifluoride 12 varnish improved mineral levels as shown by the QLF system. The treatment response to chemicals of intact noncavitated root surface carious lesions could be followed nondestructively in the clinic using QLF to quantify remineralization at recall visits. Teeth with root surface caries can be kept by controlling their remineralization.

  11. 氟对脱矿和再矿化牙釉质表面的影响%Effect to demineralization and remineralization of enamel surface by fluorine

    Institute of Scientific and Technical Information of China (English)

    吴娜; 周学东; 郝玉庆

    2012-01-01

    Objective To analyze the mechanism of fluorine by systemic analysis of fluorination-deminerarization-remineralization experiments. Methods The enamel specimens were randomly assigned to untreated group (group A), non-fluoride group (group B), low-fluoride group (group C) and high-fluoride group (group D). The in vitro model of fluoride enamel was established in group C and D. Based on that, the establishment of demineralization model and remineralization experiment by pH-cycling in group B, C and D were followed. All enamel specimens were observed by stereomicroscope and scanning electron microscope and compared in surface microhardness value. Results There was distinct difference in micro-morphologic appearance on fluoride enamel surface. Artificial caries of fluoride enamel showed a relatively complete surface, the surface microhardness after demineralization and remineralization in fluoride group was higher than non-fluoride group (P<0.05). Conclusion The fluorinated enamel can enhance cariostatic poten-tial and remineralization capacity of dental enamel.%目的 研究氟对脱矿和再矿化牙釉质表面的影响,探讨氟防龋的作用机理.方法 将牛牙釉质标本分为空白对照组(A组)、非氟化组(B组)、低氟化组(C组)和高氟化组(D组)4组,其中低氟化组和高氟化组依次进行氟化实验、脱矿实验和pH循环再矿化实验,非氟化组只进行脱矿实验和pH循环再矿化实验,空白对照组不做处理.在体视显微镜、显微硬度计和扫描电镜下观察各组釉质表面的形态变化,同时测量分析釉质表面显微硬度.结果 氟化牙釉质的表面微观形态显著不同,其脱矿损害具有相对完整的表层;氟化组在氟化、脱矿和再矿化后与非氟化组相比,表面显微硬度均有统计学差异(P<0.05).结论 氟化牙釉质可增强牙釉质的抗龋能力和再矿化效能.

  12. In vitro evaluation of the efficacy of laser fluorescence (DIAGNOdent to detect demineralization and remineralization of smooth enamel lesions

    Directory of Open Access Journals (Sweden)

    Zahra Bahrololoomi

    2013-01-01

    Full Text Available Objective: Early detection of smooth surface lesions is important for appropriate management and monitoring of dental caries. The purpose of this in vitro study was to evaluate the efficacy of laser fluorescence to detect demineralization and remineralization of smooth enamel surfaces. Materials and Methods: In this in vitro study, 132 enamel blocks of semi-impacted human third molars were obtained; artificial caries lesions were induced and they were submitted to the pH-cycling process to create remineralization. Superficial microhardness (SMH and laser fluorescence (LF analysis were performed at baseline, after demineralization, and remineralization processes. The data were analyzed by Statistical Package for Social Sciences (SPSS-16 using analysis of variance (ANOVA, Paired samples t-test, and Pearson′s correlation test. Results: There was a significant difference between SMH values at baseline, after demineralization and after remineralization. Also, a statistically significant difference was observed between LF values in these three stages. The LF values increased after demineralization and then decreased after remineralization, and the SMH values decreased after demineralization and increased after remineralization. There was an inverse relationship between SMH and LF only at baseline and after demineralization, but not after remineralization. Conclusion: The results showed that LF is an appropriate method for detection of demineralization in an in vitro condition in smooth enamel lesions, but it was not so efficient in the detection of remineralization.

  13. A Mechanistic study of Plasma Treatment Effects on Demineralized Dentin Surfaces for Improved Adhesive/Dentin Interface Bonding

    Science.gov (United States)

    Dong, Xiaoqing; Chen, Meng; Wang, Yong; Yu, Qingsong

    2014-01-01

    Our previous work has shown that non-thermal plasma treatment of demineralized dentin significantly (p<0.05) improved adhesive/dentin bonding strength for dental composite restoration as compared with the untreated controls. This study is to achieve mechanistic understanding of the plasma treatment effects on dentin surface through investigating the plasma treated dentin surfaces and their interaction with adhesive monomer, 2-Hydroxyethyl methacrylate (HEMA). The plasma treated dentin surfaces from human third molars were evaluated by water contact angle measurements and scanning electron microscopy (SEM). It was found that plasma-treated dentin surface with subsequent HEMA immersion (Plasma/HEMA Treated) had much lower water contact angle compared with only plasma-treated (Plasma Treated) or only HEMA immersed (HEMA Treated) dentin surfaces. With prolong water droplet deposition time, water droplets spread out completely on the Plasma/HEMA Treated dentin surfaces. SEM images of Plasma/HEMA Treated dentin surfaces verified that dentin tubules were opened-up and filled with HEMA monomers. Extracted type I collagen fibrils, which was used as simulation of the exposed dentinal collagen fibrils after acid etching step, were plasma treated and analyzed with Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra. FT-IR spectra of the Plasma/HEMA Treated collage fibrils showed broadened amide I peak at 1660 cm−1 and amide II at 1550 cm−1, which indicate secondary structure changes of the collagen fibrils. CD spectra indicated that 67.4% collagen helix structures were denatured after plasma treatment. These experimental results demonstrate that non-thermal argon plasma treatment was very effective in loosing collagen structure and enhancing adhesive monomer penetration, which are beneficial to thicker hybrid layer and longer resin tag formation, and consequently enhance adhesive/dentin interface bonding. PMID:25267936

  14. Sliding Wear Modeling of Artificial Rough Surfaces

    OpenAIRE

    Imam Syafa’at; Budi Setiyana; Muchammad; Jamari

    2012-01-01

    Surface roughness plays an important role in machine design. In the micro-scale when two engineering surfaces are brought into contact, the real contact area occurs at isolated point of asperity. Wear is one of some effects of contacting surfaces. This paper presents a modeling of sliding wear at asperity level on the artificial rough surfaces. The surface roughness is represented by spherical asperities at the hemispherical pin that is developed from the existing model. The wear model is bas...

  15. The significance of a differential distribution of phosphomonoesterases on bone surfaces after prolonged demineralization

    DEFF Research Database (Denmark)

    Vilmann, H; Kirkeby, S

    1979-01-01

    An observed differential distribution of alkaline and acid phosphatase on the surfaces of growing bones may serve to describe transformative processes of bone growth. This conclusion has been reached by comparing the distribution of the two enzymes on the surfaces of fibulae from young rats...... with the patterns of apposition and resorption on the periosteal surfaces of this bone, revealed by in vivo staining with alizarin red S. Presence of reaction to acid phosphatase is, as shown before, an indication of resorptive surfaces, while the presence of reaction to alkaline phosphatase is an indication...

  16. Patterns of distribution of phosphomono-esterases on surfaces of demineralized bone

    DEFF Research Database (Denmark)

    Kirkeby, S; Vilmann, H

    1979-01-01

    undergoes denaturation. Decalcification over longer periods (15 days) does not influence the pattern of distribution of acid phosphatase, whereas the alkaline phosphatase reaction becomes depressed in certain surface areas. The significance of this differential distribution is discussed. It might......Decalcification over short periods (5 days) with MnNa2 EDTA, MgNa2 EDTA and EGTA according to a method described in the present paper, creates sections of high quality with simultaneous good preservation of phosphomonoesterases on bone surfaces. In fact, the enzyme distribution seems...... be an indication of differential processes of bone transformations in such a way that bone surfaces corresponding to areas of enzyme reactions are depository whereas bone surfaces corresponding to areas of lack of enzyme reaction are resorptive. New experimental designs are, however, necessary before...

  17. Remineralization of Artificial Demineralized Cementum by CPP-ACP and Fluoride Dentifrice in vitro%CPP-ACP及氟促进脱矿牙骨质再矿化的体外实验

    Institute of Scientific and Technical Information of China (English)

    马忠雄; 卢友光; 卢国英

    2014-01-01

    Objective To assess and compare the effect of fluoride dentifrices ,CPP-ACP and CPP-ACPF in remineralization of artificial demineralized cementum . Methods Sound human cementum fragments obtained from the third molar were stored in a demineralization solution for 96 h at 37 ℃ to in-duce artificial demineralization lesions . The fragments were then randomly divided into four treatment groups including control group ,fluoride dentifrices group ,CPP-ACP group and CPP-ACPF group . The demineralized samples were treated with different material for 3 min per day . After 28 days the samples were evaluated using field emission-scanning electron microscopy (FE-SEM) . The SEM observations re-vealed different morphological features brought about by CPP-ACP ,and the energy spectrometry analysis was used to measure the mineral contents in cenentum (Ca ,P ,Ca/P) . The data was analyzed using ANOVA with SPSS17 .0 software package . Results Different thickness deposits of mineral were ob-served in each group except the control one ,and the thickest were observed in CPP-ACPF group . The mineral contents were significantly higher than those in the control group (P<0 .05) . Conclusions CPP-ACP and fluoride are all effective in remineralizing artificial demineralized cementum . CPP-ACP and flu-oride have synergistic effect in caries prevention .%目的:比较普通含氟牙膏、酪蛋白磷酸肽钙磷复合体(CPP-ACP)及含氟CPP-ACP(CPP-ACPF)促进脱矿牙骨质再矿化的效果。方法制备健康牙骨质块,开窗后脱矿液脱矿96 h ,分为空白对照组、普通含氟牙膏组、CPP-ACP组和CPP-ACPF组,每组10个样本,将实验药品按要求在牙骨质表面反复涂擦3 min ,流水冲洗5 min ,每天1次。28 d后扫描电镜观察各组牙骨质表面形貌,通过能谱分析测定牙骨质表面的微区成分(Ca、P含量及Ca/P),采用SPSS 17.0统计软件对各组间Ca、P、Ca/P进行单因素方差分析。结果扫描电

  18. Staining of dentin from amalgam corrosion is induced by demineralization

    NARCIS (Netherlands)

    J.D. Scholtanus; W. van der Hoorn; M. Özcan; M.C.D.N.J.M. Huysmans; J.F.M. Roeters; C.J. Kleverlaan; A.J. Feilzer

    2013-01-01

    PURPOSE: To evaluate the effect of artificial demineralization upon color change of dentin in contact with dental amalgam. METHODS: Sound human molars (n = 34) were embedded in resin and coronal enamel was removed. Dentin was exposed to artificial caries gel (pH 5.5) at 37 degrees C for 12 weeks (n

  19. Staining of dentin from amalgam corrosion is induced by demineralization

    NARCIS (Netherlands)

    Scholtanus, Johannes D.; van der Hoorn, Wietske; Huysmans, Marie-Charlotte D. N. J. M.; Roeters, Joost F. M.; Kleverlaan, Cornelis J.; Feilzer, Albert J.; Ozcan, Mutlu

    2013-01-01

    Purpose: To evaluate the effect of artificial demineralization upon color change of dentin in contact with dental amalgam. Methods: Sound human molars (n= 34) were embedded in resin and coronal enamel was removed. Dentin was exposed to artificial caries gel (pH 5.5) at 37 degrees C for 12 weeks (n=

  20. Microstructural analysis of demineralized primary enamel after in vitro toothbrushing

    Directory of Open Access Journals (Sweden)

    Neves Aline de Almeida

    2002-01-01

    Full Text Available The aim of this study was to investigate, in vitro, the morphological characteristics of demineralized primary enamel subjected to brushing with a dentifrice with or without fluoride. In order to do so, 32 enamel blocks were divided in 4 different groups containing 8 blocks each. They were separately immersed in artificial saliva for 15 days. The experimental groups were: C - control; E - submitted to etching with 37% phosphoric acid gel (30 s; EB - submitted to etching and brushing 3 times a day with a non-fluoridated dentifrice; EBF = submitted to etching and brushing 3 times a day with a fluoridated dentifrice. The toothbrushing force was standardized at 0.2 kgf and 15 double strokes were performed on each block. After the experimental period, the samples were prepared and examined under SEM. The control group (C showed a smooth surface, presenting scratches caused by habitual toothbrushing. The etched samples (E exhibited different degrees of surface disintegration, but the pattern of acid etching was predominantly the type II dissolution. The brushed surfaces were smooth, with elevations which corresponded to the exposure of Tomes? process pits and depressions which corresponded to interrod enamel. Particles resembling calcium carbonate were found in the most protected parts of the grooves. No morphological differences were observed between brushing with fluoridated (EBF and non-fluoridated (EB dentifrice. The results suggest that the mechanical abrasion caused by brushing demineralized enamel with dentifrice smoothes the rough etched surface, and the presence of fluoride does not cause morphological modifications in this pattern.

  1. Steering the osteoclast through the demineralization-collagenolysis balance

    DEFF Research Database (Denmark)

    Søe, Kent; Merrild, Ditte Marie Horslev; Delaissé, Jean-Marie

    2013-01-01

    , forming a pit, and continues parallel to the bone surface, forming a trench. Importantly, we show that the progress of the osteoclast along this route depends on the balance between the rate of collagenolysis and demineralization. We propose that the osteocytes and bone lining cells surrounding......There is a lot of interest for how and how much osteoclasts resorb bone. However, little is known about the mechanism which controls the orientation and the duration of a resorptive event, thereby determining the specific geometry of a cavitation. Here we show that the relative rate...... of collagenolysis vs. demineralization plays a critical role in this process. First we observed that when culturing osteoclasts on bone slices, excavations appeared either as round pits containing demineralized collagen, or as elongated trenches without demineralized collagen. This suggests that round pits...

  2. Effect of Nd:YAG laser combined with fluoride on the prevention of primary tooth enamel demineralization.

    Science.gov (United States)

    Azevedo, Danielle Torres; Faraoni-Romano, Juliana Jendiroba; Derceli, Juliana Dos Reis; Palma-Dibb, Regina Guenka

    2012-01-01

    Most studies dealing with the caries preventive action of Nd:YAG laser have been done in permanent teeth and studies on primary teeth are still lacking. The aim of this study was to evaluate in vitro the effect of Nd:YAG laser combined or not with fluoride sources on the acid resistance of primary tooth enamel after artificial caries induction by assessing longitudinal microhardness and demineralization depth. Sixty enamel blocks obtained from the buccal/lingual surface of exfoliated human primary molars were coated with nail polish/wax, leaving only a 9 mm² area exposed on the outer enamel surface, and randomly assigned to 6 groups (n=10) according to the type of treatment: C-control (no treatment); APF: 1.23% acidulated phosphate fluoride gel; FV: 5% fluoride varnish; L: Nd:YAG laser 0.5 W/10 Hz in contact mode; APFL: fluoride gel + laser; FVL: fluoride varnish + laser. After treatment, the specimens were subjected to a des-remineralization cycle for induction of artificial caries lesions. Longitudinal microhardness data (%LMC) were analyzed by the Kruskal-Wallis test and demineralization depth data were analyzed by oneway ANOVA and Fisher's LSD test (á=0.05). APFL and APF groups presented the lowest percentage of microhardness change (p<0.05). Demineralization depth was smaller in all treated groups compared with the untreated control. In conclusion, Nd:YAG laser combined or not with fluoride gel/varnish was not more effective than fluoride alone to prevent enamel demineralization within the experimental period. PMID:22666766

  3. Removal of different fractions of NOM foulants during demineralized water backwashing

    KAUST Repository

    Li, Sheng

    2012-09-01

    The effectiveness of demineralized water backwashing on fouling by different fractions of NOM was investigated in this study. Two types of natural surface water (Schie canal and Biesbosch reservoir) were tested to confirm the improvement of demineralized water backwashing on fouling control, and LC-OCD analysis was conducted on Schie canal water to find out which fraction of NOM was removed with those backwashes. Results derived from natural waters showed that demineralized water backwashing substantially improved UF fouling control. LC-OCD analyses showed both UF permeate and demineralized water backwashes were effective on removing part of biopolymers, but demineralized water is also effective for humic substances and a limited amount of low molecular weight substances. However, based on the LC-OCD results, even demineralized water backwashing is not effective to remove all humic substances and biopolymers rejected on the UF membranes. © 2012 Elsevier B.V. All rights reserved.

  4. Secondary coolant purification system with demineralizer bypass

    International Nuclear Information System (INIS)

    Apparatus and method are provided for a nuclear stream supply system for adequately controlling the chemistry of the secondary coolant. The invention includes means for the addition of volatile chemicals, a full flow condensate demineralizer, continuous blowdown capability, radiation detection means, a condensate demineralizer bypass line, and an auxiliary demineralizer bypass line, and an auxiliary demineralizer sized to handle full blowdown flow. The auxiliary demineralizer is cut into the system and the steam generator feedwater flow is bypassed around the full flow condensate demineralizer whenever radioactivity is detected in the secondary coolant

  5. The effect of stromelysin-1 (MMP-3) on non-collagenous extracellular matrix proteins of demineralized dentin and the adhesive properties of restorative resins.

    Science.gov (United States)

    Boukpessi, T; Menashi, S; Camoin, L; Tencate, J M; Goldberg, M; Chaussain-Miller, C

    2008-11-01

    Dentin non-collagenous matrix components (NCPs) are structural proteins involved in the formation, the architecture and the mineralization of the extracellular matrix (ECM). We investigated here how recombinant metalloproteinase stromelysin-1, also termed MMP-3, initiates the release of ECM molecules from artificially demineralized human dentin. Analysis of the supernatants by Western blotting reveals that MMP-3 extracts PGs (decorin, biglycan), and also a series of phosphorylated proteins: dentin sialoprotein (DSP), osteopontin (OPN), bone sialoprotein (BSP) and MEPE, but neither dentin matrix protein-1 (DMP1), another member of the SIBLING family, nor osteocalcin (OC), a non-phosphorylated matrix molecule. After treatment of dentin surfaces by MMP-3, scanning electron microscope (SEM) examination of resin replica shows an increased penetration of the resin into the dentin tubules when compared to surfaces only treated by demineralizing solutions. This preclinical investigation suggests that MMP-3 may be used to improve the adhesive properties of restorative materials.

  6. Artificial ocean upwelling utilizing the energy of surface waves

    Science.gov (United States)

    Soloviev, Alexander

    2016-04-01

    Artificial upwelling can bring cold water from below the thermocline to the sea surface. Vershinsky, Pshenichnyy, and Soloviev (1987) developed a prototype device, utilizing the energy of surface waves to create an upward flow of water in the tube. This is a wave-inertia pump consisting of a vertical tube, a valve, and a buoy to keep the device afloat. An outlet valve at the top of the unit synchronizes the operation of the device with surface waves and prevents back-splashing. A single device with a 100 m long and 1.2 m diameter tube is able to produce up to 1 m3s-1 flow of deep water to the surface. With a 10 oC temperature difference over 100 m depth, the negative heat supply rate to the sea surface is 42 MW, which is equivalent to a 42 Wm-2 heat flux, if distributed over 1 km2 area. Such flux is comparable to the average net air-sea flux. A system of artificial upwelling devices can cool down the sea surface, modify climate on a regional scale and possibly help mitigate hurricanes. The cold water brought from a deeper layer, however, has a larger density than the surface water and therefore has a tendency to sink back down. In this work, the efficiency of wave-inertia pumps and climatic consequences are estimated for different environmental conditions using a computational fluid dynamics model.

  7. Textured bearing surface in artificial joints to reduce macrophage activation

    Science.gov (United States)

    Nakanishi, Yoshitaka; Nishi, Naoki; Chikaura, Hiroto; Nakashima, Yuta; Miura, Hiromasa; Higaki, Hidehiko; Mizuta, Hiroshi; Iwamoto, Yukihide; Fujiwara, Yukio; Komohara, Yoshihiro; Takeya, Motohiro

    2015-12-01

    Micro slurry-jet erosion has been proposed as a precision machining technique for the bearing surfaces of artificial joints in order to reduce the total amount of polyethylene wear and to enlarge the size of the wear debris. The micro slurry-jet erosion method is a wet blasting technique which uses alumina particles as the abrasive medium along with compressed air and water to create an ideal surface. Pin-on-disc wear tests with multidirectional sliding motion on the textured surface of a \\text{Co}-\\text{Cr}-\\text{Mo} alloy counterface for polyethylene resulted in both a reduction of wear as well as enlargement of the polyethylene debris size. In this study, primary human peripheral blood mononuclear phagocytes were incubated with the debris, and it was elucidated that the wear debris generated on the textured surface regulated secretion of the proinflammatory cytokines IL-6 and TNF-α, indicating a reduction in the induced tissue reaction and joint loosening.

  8. Analysis of surface hardness of artificially aged resin composites

    Directory of Open Access Journals (Sweden)

    Denise Cremonezzi Tornavoi

    2012-02-01

    Full Text Available This study evaluated the effect of artificially accelerated aging (AAA on the surface hardness of eight composite resins: Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma, and Filtek Z100. Sixteen specimens were made from the test piece of each material, using an 8.0 × 2.0 mm teflon matrix. After 24 hours, eight specimens from each material were submitted to three surface hardness readings using a Shimadzu Microhardness Tester for 5 seconds at a load of 50 gf. The other eight specimens remained in the artificially accelerated aging machine for 382 hours and were submitted to the same surface hardness analysis. The means of each test specimen were submitted to the Kolmogorov-Smirnov test (p > 0.05, ANOVA and Tukey test (p < 0.05. With regard to hardness (F = 86.74, p < 0.0001 the analysis showed significant differences among the resin composite brands. But aging did not influence the hardness of any of the resin composites (F = 0.39, p = 0.53. In this study, there was interaction between the resin composite brand and the aging factors (F = 4.51, p < 0.0002. It was concluded that notwithstanding the type of resin, AAA did not influence surface hardness. However, with regard to hardness there was a significant difference among the resin brands.

  9. EFFECT OF AIR-DRYING ON DEMINERALIZED AND ON SOUND CORONAL HUMAN DENTIN - A STUDY ON DENSITY AND ON LESION SHRINKAGE

    NARCIS (Netherlands)

    ARENDS, J; RUBEN, J

    1995-01-01

    Recently, several papers investigated the linear dimensional changes in dentine after air-drying. This paper pertains to weight changes, volume changes, and density changes caused by air-drying of sound and demineralized intact dentine. The densities of sound and artificially demineralized human cor

  10. Effect of caries infiltrant application on shear bond strength of different adhesive systems to sound and demineralized enamel

    OpenAIRE

    Jia, Liuhe; Stawarczyk, Bogna; Schmidlin, Patrick R; Attin, Thomas; Wiegand, Annette

    2012-01-01

    Purpose: To investigate the influence of caries infiltrant application on the shear bond strength of different adhesives on sound and demineralized enamel. Materials and Methods: Sound and artificially demineralized (14 days, acidic buffer, pH 5.0) bovine enamel specimens were treated with a caries infiltrant (Icon, DMG), three different commercial adhesives (unfilled etchand- rinse adhesive: Heliobond, Ivoclar Vivadent; filled etch-and-rinse adhesive: Optibond FL, Kerr; or self-etching adhes...

  11. Effects of ammonium hexafluorosilicate application on demineralized enamel and dentin of primary teeth.

    Science.gov (United States)

    Hosoya, Yumiko; Watanabe, Eiko; Tadokoro, Katsumi; Inoue, Takashi; Miyazaki, Masashi; Tay, Franklin R

    2012-09-01

    Silver diamine fluoride (Ag(NH(3))(2)F) arrests caries but stains teeth black. To overcome this drawback, we applied ammonium hexafluorosilicate (AHF; (NH(4))(2)SiF(6)) and observed changes in the color and structure of demineralized enamel and dentin of extracted primary teeth. Enamel and dentin were demineralized in 10% EDTA solution for 90 s followed by 35% phosphoric acid gel for 60 s, then soaked in AHF solution for 60 s. Before analysis by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS), enamel and dentin were demineralized in 10% EDTA for 90 s. Teeth were divided into 4 groups according to AHF application and artificial saliva immersion status and then examined. The data were statistically analyzed using one-way ANOVA and Fisher's PLSD test at a significance level of P caries treatment is required. PMID:23047038

  12. Remineralizing efficacy of Calcarea Fluorica tablets on the artificial carious enamel lesions using scanning electron microscope and surface microhardness testing: In vivostudy

    OpenAIRE

    Kalpana Bansal; Nidhi Balhara; Mohita Marwaha

    2014-01-01

    Context: Remineralization is defined as the process whereby calcium and phosphate ions are supplied from a source external to tooth to promote ion deposition into crystal voids in demineralized enamel to produce net mineral gain. The remineralization produced by saliva is less and also a slow process, therefore remineralizing agents are required. Aims: The study was planned to evaluate the effectiveness of homeopathic Calcarea Fluorica (calc-f) tablets as remineralizing agents on artifici...

  13. Nondestructive Assessment of Early Tooth Demineralization Using Cross-Polarization Optical Coherence Tomography.

    Science.gov (United States)

    Kang, Hobin; Jiao, Jian J; Lee, Chulsung; Le, Michael H; Darling, Cynthia L; Fried, Daniel

    2010-07-01

    New methods are needed for the nondestructive measurement of tooth demineralization and remineralization to monitor the progression of incipient caries lesions (tooth decay) for effective nonsurgical intervention and to evaluate the performance of anticaries treatments such as chemical treatments or laser irradiation. Studies have shown that optical coherence tomography (OCT) has great potential to fulfill this role since it can be used to measure the depth and severity of early lesions with an axial resolution exceeding 10 µm, it is easy to apply in vivo and it can be used to image the convoluted topography of tooth occlusal surfaces. In this paper, a review of the use of polarization-sensitive-OCT for the measurement of tooth demineralization is provided along with some recent results regarding improved methods for the detection of caries lesions in the earliest stages of development. Automated methods of analysis were used to measure the depth and severity of demineralized bovine enamel produced using simulated caries models that emulate demineralization in the mouth. Significant differences in the depth and integrated reflectivity from the lesions were detected after only a few hours of demineralization. These results demonstrate that cross-polarization-OCT is ideally suited for the nondestructive assessment of early demineralization. PMID:21660217

  14. Artificial neural network accurately predicts hepatitis B surface antigen seroclearance.

    Directory of Open Access Journals (Sweden)

    Ming-Hua Zheng

    Full Text Available BACKGROUND & AIMS: Hepatitis B surface antigen (HBsAg seroclearance and seroconversion are regarded as favorable outcomes of chronic hepatitis B (CHB. This study aimed to develop artificial neural networks (ANNs that could accurately predict HBsAg seroclearance or seroconversion on the basis of available serum variables. METHODS: Data from 203 untreated, HBeAg-negative CHB patients with spontaneous HBsAg seroclearance (63 with HBsAg seroconversion, and 203 age- and sex-matched HBeAg-negative controls were analyzed. ANNs and logistic regression models (LRMs were built and tested according to HBsAg seroclearance and seroconversion. Predictive accuracy was assessed with area under the receiver operating characteristic curve (AUROC. RESULTS: Serum quantitative HBsAg (qHBsAg and HBV DNA levels, qHBsAg and HBV DNA reduction were related to HBsAg seroclearance (P<0.001 and were used for ANN/LRM-HBsAg seroclearance building, whereas, qHBsAg reduction was not associated with ANN-HBsAg seroconversion (P = 0.197 and LRM-HBsAg seroconversion was solely based on qHBsAg (P = 0.01. For HBsAg seroclearance, AUROCs of ANN were 0.96, 0.93 and 0.95 for the training, testing and genotype B subgroups respectively. They were significantly higher than those of LRM, qHBsAg and HBV DNA (all P<0.05. Although the performance of ANN-HBsAg seroconversion (AUROC 0.757 was inferior to that for HBsAg seroclearance, it tended to be better than those of LRM, qHBsAg and HBV DNA. CONCLUSIONS: ANN identifies spontaneous HBsAg seroclearance in HBeAg-negative CHB patients with better accuracy, on the basis of easily available serum data. More useful predictors for HBsAg seroconversion are still needed to be explored in the future.

  15. TMI-2 purification demineralizer resin study

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, J D; Osterhoudt, T R

    1984-05-01

    Study of the Makeup and Purification System demineralizers at TMI-2 has established that fuel quantities in the vessels are low, precluding criticality, that the high radioactive cesium concentration on the demineralizer resins can be chemically removed, and that the demineralizer resins can probably be removed from the vessels by sluicing through existing plant piping. Radiation measurements from outside the demineralizers establishing that there is between 1.5 and 5.1 (probably 3.3) lb of fuel in the A vessel and less than that amount in the B vessel. Dose rates up to 2780 R per hour were measured on contact with the A demineralizer. Remote visual observation of the A demineralizer showed a crystalline crust overlaying amber-colored resins. The cesium activity in solid resin samples ranged from 220 to 16,900 ..mu..Ci/g. Based on this information, researchers concluded that the resins cannot be removed through the normal pathway in their present condition. Studies do show that the resins will withstand chemical processing designed to rinse and elute cesium from the resins. The process developed should work on the TMI-2 resins.

  16. Artificial Molecular Machine Immobilized Surfaces: A New Platform To Construct Functional Materials.

    Science.gov (United States)

    Zhang, Qi; Qu, Da-Hui

    2016-06-17

    Artificial molecular machines have received significant attention from chemists because of their unique ability to mimic the behaviors of biological systems. Artificial molecular machines can be easily modified with functional groups to construct new types of functional molecular switches. However, practical applications of artificial molecular machines are still challenging, because the working platform of artificial molecular machines is mostly in solution. Artificial molecular machine immobilized surfaces (AMMISs) are considered a promising platform to construct functional materials. Herein, we provide a minireview of some recent advances of functional AMMISs. The functions of AMMISs are highlighted and strategies for their construction are also discussed. Furthermore, a brief perspective of the development of artificial molecular machines towards functional materials is given.

  17. Seawater ultrafiltration fouling control: Backwashing with demineralized water/SWRO permeate

    KAUST Repository

    Li, Sheng

    2012-09-01

    In this study, the effect of demineralized water backwashing on fouling control of seawater ultrafiltration was investigated. Seawater from Scheveningen beach in The Hague and a desalination plant of Evides Company at Zeeland in the Netherlands was used as feed water, while demineralized water and UF permeate were used as backwash water for a fouling control efficiency comparison under different fluxes and backwash durations. Furthermore, demineralized waters with 5 or 50 mmol/l NaCl were applied for backwashing as well, to check the influence of monovalent cations on UF fouling control. Additionally, SWRO permeate was used for backwashes in long-term experiments to check the possibility of it replacing demineralized water. Results show that seawater UF fouling control is substantially improved by demineralized water backwashing. However, due to the high salinity of seawater, more water was required to dilute the cation concentration and limit the dispersion effect near the membrane surface than was needed for surface water. A 2-min demineralized water backwash showed better fouling control efficiency than a 1-min backwash. Furthermore, the presence of monovalent cations in the backwash water deteriorated the fouling control efficiency of the backwash, indicating the existence of a charge screening effect. The demineralized water with 5 and 50 mmol/l NaCl both showed a similar fouling control efficiency which is better than the UF permeate backwash. The calcium ions in UF permeate probably deteriorates the fouling control efficiency by maintaining a Ca-bridging effect between the membranes and NOM. SWRO permeate backwashing successfully controls membrane fouling as well. © 2012 Elsevier B.V. All rights reserved.

  18. Response surface and artificial neural network prediction model and optimization for surface roughness in machining

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Sahoo

    2015-04-01

    Full Text Available The present paper deals with the development of prediction model using response surface methodology and artificial neural network and optimizes the process parameter using 3D surface plot. The experiment has been conducted using coated carbide insert in machining AISI 1040 steel under dry environment. The coefficient of determination value for RSM model is found to be high (R2 = 0.99 close to unity. It indicates the goodness of fit for the model and high significance of the model. The percentage of error for RSM model is found to be only from -2.63 to 2.47. The maximum error between ANN model and experimental lies between -1.27 and 0.02 %, which is significantly less than the RSM model. Hence, both the proposed RSM and ANN prediction model sufficiently predict the surface roughness, accurately. However, ANN prediction model seems to be better compared with RSM model. From the 3D surface plots, the optimal parametric combination for the lowest surface roughness is d1-f1-v3 i.e. depth of cut of 0.1 mm, feed of 0.04 mm/rev and cutting speed of 260 m/min respectively.

  19. Estimates of global dew collection potential on artificial surfaces

    OpenAIRE

    Vuollekoski, H.; Vogt, M; V. A. Sinclair; J. Duplissy; Järvinen, H; Kyrö, E.-M.; Makkonen, R.; T. Petäjä; N. L. Prisle; P. Räisänen; Sipilä, M.; Ylhäisi, J.; M. Kulmala

    2015-01-01

    The global potential for collecting usable water from dew on an artificial collector sheet was investigated by utilizing 34 years of meteorological reanalysis data as input to a dew formation model. Continental dew formation was found to be frequent and common, but daily yields were mostly below 0.1 mm. Nevertheless, some water-stressed areas such as parts of the coastal regions of northern Africa and the Arabian Peninsula show potential for large-scale dew harvesting, as th...

  20. Comparative analysis of optical coherence tomography signal and microhardness for demineralization evaluation of human tooth enamel

    Science.gov (United States)

    de Cara, Ana Claudia Ballet; Zezell, Denise Maria; Ana, Patricia A.; Deana, Alessandro Melo; Amaral, Marcello Magri; Dias Vieira, Nilson, Jr.; de Freitas, Anderson Zanardi

    2012-06-01

    The diagnosis of dental caries at an early stage enables the implementation of conservative treatments based on dental preservation. Several diagnostic methods have been developed, like visual-tactile and radiographic are the most commons but are limited for this application. The Optical Coherence Tomography is a technique that provides information of optical properties of enamel, which may change due to the decay process. The objective of this study was to evaluate the ability of OCT to detect different stages of demineralization of tooth enamel during the development of artificial caries lesions, taking as a reference standard for comparison sectional microhardness testing. Different stages of caries lesions were simulated using the pH cycling model suggested Feathestone and modified by Argenta. The samples were exposed to 0 (control group), 5, 10, 15, 20 and 25 days at a daily regimen of three hours demineralization followed by remineralization during 20 hours. It was used an OCT system with at 930nm. Sectional images were generated in all lesion region. The results obtained from the OCT technique presented similar behavior to microhardness, except for the group 25 days, due to inability to perform indentations reading in areas of more intense demineralization. A linear relationship was observed between the OCT and microhardness techniques for detection of demineralization in enamel. This relationship will allow the use of OCT technique in quantitative assessment of mineral loss and for the evaluation of incipient caries lesions.

  1. Effect of fluoride toothpastes on enamel demineralization

    Directory of Open Access Journals (Sweden)

    Gintner Zeno

    2006-06-01

    Full Text Available Abstract Background It was the aim of this study to investigate the effect of four different toothpastes with differing fluoride compounds on enamel remineralization. Methods A 3 × 3 mm window on the enamel surface of 90 human premolars was demineralized in a hydroxyethylcellulose solution at pH 4.8. The teeth were divided into 6 groups and the lower half of the window was covered with varnish serving as control. The teeth were immersed in a toothpaste slurry containing: placebo tooth paste (group 1; remineralization solution (group 2; Elmex Anticaries (group 3; Elmex Sensitive (group 4; Blend-a-med Complete (group 5 and Colgate GRF (group 6. Ten teeth of each group were used for the determination of the F- content in the superficial enamel layer and acid solubility of enamel expressed in soluble phosphorus. Of 6 teeth of each group serial sections were cut and investigated with polarization light microscopy (PLM and quantitative energy dispersive X-ray analysis (EDX. Results The PLM results showed an increased remineralization of the lesion body in the Elmex Anticaries, Elmex Sensitive and Colgate GRF group but not in the Blend-a-med group. A statistically significant higher Ca content was found in the Elmex Anticaries group. The fluoride content in the superficial enamel layer was significantly increased in both Elmex groups and the Blend-a-med group. Phosphorus solubility was significantly decreased in both Elmex groups and the Blend-a-med group. Conclusion It can be concluded that amine fluoride compounds in toothpastes result in a clearly marked remineralization of caries like enamel lesions followed by sodium fluoride and sodium monofluorophosphate formulations.

  2. Evaluation of human dentine demineralization of yellow race by Raman spectra

    Science.gov (United States)

    Zhan, Zhenlin; Guo, Wenqing; Liu, Haishan; Zhang, Xianzeng; Xie, Shusen

    2012-12-01

    The aim of this study is to evaluate the demineralization process in human dentine using Raman spectroscopy (RS). Nine human molars from Chinese subjects were cut into twelve tooth sections. The sections were painted with an acidresistant varnish leaving one dentine surface exposed and then immersed into 0.3% citric acid to simulate the oral natural demineralization. According to the acid-etch time, specimens were randomly divided into four groups: Ⅰ5 min, Ⅱ 10 min, Ⅲ 20 min and Ⅳ 40 min. Raman spectra were measured before and after each treatment. The result showed that no new bands, bands shifts, or disappearance of bands occurred in the whole process. However, the peak intensities of inorganic constituents decreased with the increase of acid-etch time, while the trends of organic constituents were opposite. In conclusion, RS could be able to efficiently monitor the demineralization status of human dentine.

  3. Artificial Crater Formation on Satellite Surfaces Using an Orbiting Railgun

    Science.gov (United States)

    Dissly, R. W.; Miller, K. L.; Carlson, R. J.

    2003-01-01

    The specification of greater than 45kW of disposable power available on the JIMO spacecraft raises the possibility of a new class of instrumentation that has utility at such power levels. In this presentation we discuss the concept of an electromagnetic mass driver that can launch projectiles from orbit around one of the Galilean satellites directed on a trajectory that will impact the satellite surface. The resulting impact will create a crater that will provide information on the mechanical properties of surface and near-surface materials, expose subsurface materials for remote spectral identification, and form a vapor cloud that can be sensed for composition either remotely or in-situ. An analog for such a controlled cratering experiment is Deep Impact, a mission to observe the crater and ensuing ejecta cloud formed by a ballistic projectile into a comet surface in July, 2005.

  4. Effect of denture base-resin with prereacted glass-ionomer filler on dentin demineralization

    NARCIS (Netherlands)

    Y. Mukai; K. Kamijo; F. Fujino; T. Teranaka; J.M. ten Cate

    2009-01-01

    The demineralization of dentin was studied when placed adjacent to one of four experimental denture base-resins. These experimental resins contained polymethylmethacrylate (PMMA) and 0, 5, 10, 20 or 30 wt% surface reaction-type prereacted glass-ionomer (S-PRG) filler, respectively. A dentin thin-sec

  5. Modeling the Probability of Surface Artificialization in Zêzere Watershed (Portugal Using Environmental Data

    Directory of Open Access Journals (Sweden)

    Bruno M. Meneses

    2016-07-01

    Full Text Available The land use and land cover (LUC of the Zêzere watershed (Portugal have undergone major changes in recent decades, with the increase of artificial surfaces. This trend is quantified in some studies, but the probability of the increase of this type of LUC, nor the places where the next transitions or land use/cover changes (LUCC for artificial surfaces will have high probability of occurrence has not yet been assessed. This research presents an evaluation of these two aspects, by means of bivariate statistical models (fuzzy logic and information value and environmental data. The artificialization probability by sectors within the same watershed is also evaluated, to further understand which areas will require greater attention, taking into account the environmental conditions favorable to the occurrence of this process and bearing in mind the conditions under which this process took place in the past. The results obtained using these models were assessed independently, through curves of success, noting that the modeling through the fuzzy gamma presents slightly better efficiency in determining the probability of artificialization surfaces in the study area. The area with the highest probability of artificialization is mostly located in the SW of this watershed, but high probabilities are also present in the upstream sector, being those areas that require further preventive measures once they have influence on the water quality and quantity in the main reservoirs of this watershed.

  6. Acid demineralization susceptibility of dental enamel submitted to different bleaching techniques and fluoridation regimens.

    Science.gov (United States)

    Salomão, Dlf; Santos, Dm; Nogueira, Rd; Palma-Dibb, Rg; Geraldo-Martins, Vr

    2014-01-01

    The aim of the current study was to assess the acid demineralization susceptibility of bleached dental enamel submitted to different fluoride regimens. One hundred bovine enamel blocks (6×6×3 mm) were randomly divided into 10 groups (n=10). Groups 1 and 2 received no bleaching. Groups 3 to 6 were submitted to an at-home bleaching technique using 6% hydrogen peroxide (HP; G3 and G4) or 10% carbamide peroxide (CP; G5 and G6). Groups 7 to 10 were submitted to an in-office bleaching technique using 35% HP (G7 and G8) or 35% CP (G9 and G10). During bleaching, a daily fluoridation regimen of 0.05% sodium fluoride (NaF) solution was performed on groups 3, 5, 7, and 9, while weekly fluoridation with a 2% NaF gel was performed on groups 4, 6, 8, and 10. The samples in groups 2 to 10 were pH cycled for 14 consecutive days. The samples from all groups were then assessed by cross-sectional Knoop microhardness at different depths from the outer enamel surface. The average Knoop hardness numbers (KHNs) were compared using one-way analysis of variance and Tukey tests (α=0.05). The comparison between groups 1 and 2 showed that the demineralization method was effective. The comparison among groups 2 to 6 showed the same susceptibility to acid demineralization, regardless of the fluoridation method used. However, the samples from groups 8 and 10 showed more susceptibility to acid demineralization when compared with group 2 (penamel to acid demineralization. However, the use of 35% HP and 35% CP must be associated with a daily fluoridation regimen, otherwise the in-office bleaching makes the bleached enamel more susceptible to acid demineralization.

  7. AN ARTIFICIAL INTELLIGENCE APPROACH FOR THE PREDICTION OF SURFACE ROUGHNESS IN CO2 LASER CUTTING

    Directory of Open Access Journals (Sweden)

    MILOŠ MADIĆ

    2012-12-01

    Full Text Available In laser cutting, the cut quality is of great importance. Multiple non-linear effects of process parameters and their interactions make very difficult to predict cut quality. In this paper, artificial intelligence (AI approach was applied to predict the surface roughness in CO2 laser cutting. To this aim, artificial neural network (ANN model of surface roughness was developed in terms of cutting speed, laser power and assist gas pressure. The experimental results obtained from Taguchi’s L25 orthogonal array were used to develop ANN model. The ANN mathematical model of surface roughness was expressed as explicit nonlinear function of the selected input parameters. Statistical results indicate that the ANN model can predict the surface roughness with good accuracy. It was showed that ANNs may be used as a good alternative in analyzing the effects of cutting parameters on the surface roughness.

  8. Imaging early demineralization with PS-OCT

    OpenAIRE

    Kang, Hobin; Jiao, Jane J.; Lee, Chulsung; Darling, Cynthia L.; Fried, Daniel

    2010-01-01

    New methods are needed for the nondestructive measurement of tooth demineralization and remineralization to monitor the progression of incipient caries lesions (tooth decay) for effective nonsurgical intervention and to evaluate the performance of anti-caries treatments such as chemical treatments or laser irradiation. Studies have shown that optical coherence tomography (OCT) has great potential to fulfill this role since it can be used to measure the depth and severity of early lesions with...

  9. 渗透树脂治疗对人工釉质龋表面微硬度影响的研究%Effect of resin infiltration on enamel surface microhardness of artificial enamel caries

    Institute of Scientific and Technical Information of China (English)

    赵晓一; 高学军

    2014-01-01

    目的:观察不同脱矿程度人工釉质龋经渗透树脂治疗后其表面微硬度的提高程度。方法:制备牛牙釉质样本60个,随机分为6组,分别置脱矿液中脱矿10、20、30、40、50、60 d;然后用ICON渗透树脂对各组人工釉质龋病损部位进行处理;分别于脱矿前、脱矿后、渗透树脂后用韦氏微硬度仪检测各组病损表面的微硬度值,用3D激光扫描显微系统观察病损表面的形貌。结果:各组样本脱矿前表面微硬度值基本一致(P>0.05),脱矿后均明显降低(P<0.05);经渗透树脂处理后,病损表面微硬度均显著提高(P<0.05),但低于基线水平(P<0.05),依次为脱矿60 d<50 d<40 d<30 d<20 d<10 d,10、20、30、40 d各组间无显著性差异(P>0.05)外,其他各组间差异均有统计学意义(P<0.05)。抛光后的釉质表面无树脂残留。结论:渗透树脂能提高釉质龋病损表面的微硬度,但不能达到正常釉质的水平;提高程度与病损脱矿程度相关。%AIM:To evaluate the effect of resin infiltration treatment on enamel surface microhardness (SMH)of artificial caries lesions.METHODS:60 bovine enamel specimens were divided into 6 groups (n=10)and were demineralized for 10 d,20 d,30 d,50 d and 60 d (group 1,2,3,4,5,and 6)respectively.The caries le-sions were etched with 37%phosphoric acid gel and infiltrated with ICON resin.The SMH of the specimens before and after demineralization,and after resin infiltration was determined by Laser Microscope 3D&Profile Measurement.RE-SULTS:The specimens of all groups exhibited the same baseline level of SMH(P>0.05 ).After demineralization, the SMH of all groups was time-dependently reduced(P<0.05 ).SMH in all groups incteased after resin infiltration and polishing (P<0.05),but not achieved to the baseline.No significant difference in the amount of SMH re-hard-ening was detected between each 2 of group 1

  10. Natural and Controlled Demineralization for Study Purposes in Minimally Invasive Dentistry.

    Science.gov (United States)

    Skucha-Nowak, Małgorzata; Gibas, Mirosław; Tanasiewicz, Marta; Twardawa, Henryk; Szklarski, Tomasz

    2015-01-01

    Artificially induced demineralization of enamel is frequently used during laboratory tests, particularly in minimally invasive dentistry. The aim of this study was to analyze demineralization techniques of hard tooth tissue applicable in the research of materials in minimally invasive dentistry. The most important factor taken into consideration when designing a method is to make a model as closely similar to the natural environment of the human oral cavity as it is possible. In vitro models allow us to maintain stability and control over the environment and guarantee repeatability of the results. There are main models to produce dental caries outside of the body. The first model is chemical and it uses acids. It is simplified and reflects the actual environment of the oral cavity to a lesser degree. The second model is biological and it is more accurate as it uses microorganisms which build the dental plaque. Among in vitro protocols are also used pH-cycling models. Based on the available literature, it was found that bovine teeth and human teeth with demineralization diagnosed while still inside the oral cavity are the most frequently used kind of specimens in research conducted with use of the chemical model. Not a single case of use of the biological and pH-cycling models were found in the available literature related to the research of infiltrants in minimally invasive dentistry. PMID:26768642

  11. Natural and Controlled Demineralization for Study Purposes in Minimally Invasive Dentistry.

    Science.gov (United States)

    Skucha-Nowak, Małgorzata; Gibas, Mirosław; Tanasiewicz, Marta; Twardawa, Henryk; Szklarski, Tomasz

    2015-01-01

    Artificially induced demineralization of enamel is frequently used during laboratory tests, particularly in minimally invasive dentistry. The aim of this study was to analyze demineralization techniques of hard tooth tissue applicable in the research of materials in minimally invasive dentistry. The most important factor taken into consideration when designing a method is to make a model as closely similar to the natural environment of the human oral cavity as it is possible. In vitro models allow us to maintain stability and control over the environment and guarantee repeatability of the results. There are main models to produce dental caries outside of the body. The first model is chemical and it uses acids. It is simplified and reflects the actual environment of the oral cavity to a lesser degree. The second model is biological and it is more accurate as it uses microorganisms which build the dental plaque. Among in vitro protocols are also used pH-cycling models. Based on the available literature, it was found that bovine teeth and human teeth with demineralization diagnosed while still inside the oral cavity are the most frequently used kind of specimens in research conducted with use of the chemical model. Not a single case of use of the biological and pH-cycling models were found in the available literature related to the research of infiltrants in minimally invasive dentistry.

  12. Photolysis of Nitric Acid and Nitrate on Natural and Artificial Surfaces.

    Science.gov (United States)

    Ye, Chunxiang; Gao, Honglian; Zhang, Ning; Zhou, Xianliang

    2016-04-01

    Photolysis of nitric acid and nitrate (HNO3/nitrate) was investigated on the surfaces of natural and artificial materials, including plant leaves, metal sheets, and construction materials. The surfaces were conditioned in the outdoor air prior to experiments to receive natural depositions of ambient HNO3/nitrate and other atmospheric constituents. The photolysis rate constant (JHNO3(s)) of the surface HNO3/nitrate was measured based on the production rates of nitrous acid (HONO) and nitrogen oxides (NOx). The JHNO3(s) values, from 6.0 × 10(-6) s(-1) to 3.7 × 10(-4) s(-1), are 1 to 3 orders of magnitude higher than that of gaseous HNO3. The HONO was the major product from photolysis of HNO3/nitrate on most plant leaves, whereas NOx was the major product on most artificial surfaces. The JHNO3(s) values decreased with HNO3/nitrate surface density and could be described by a simple analytical equation. Within a typical range of HNO3/nitrate surface density in the low-NOx forested areas, photolysis of HNO3/nitrate on the forest canopy can be a significant source for HONO and NOx for the overlying atmosphere. PMID:26936001

  13. Double Glow Plasma Surface Alloying Process Modeling Using Artificial Neural Networks

    Institute of Scientific and Technical Information of China (English)

    Jiang XU; Xishan XIE; Zhong XU

    2003-01-01

    A model is developed for predicting the correlation between processing parameters and the technical target of double glowby applying artificial neural network (ANN). The input parameters of the neural network (NN) are source voltage, workpiecevoltage, working pressure and distance between source electrode and workpiece. The output of the NN model is three importanttechnical targets, namely the gross element content, the thickness of surface alloying layer and the absorption rate (the ratioof the mass loss of source materials to the increasing mass of workpiece) in the processing of double glow plasma surfacealloying. The processing parameters and technical target are then used as a training set for an artificial neural network. Themodel is based on multiplayer feedforward neural network. A very good performance of the neural network is achieved and thecalculated results are in good agreement with the experimental ones.

  14. Ability of Pit and Fissure Sealant-containing Amorphous Calcium Phosphate to inhibit Enamel Demineralization

    OpenAIRE

    Zawaideh, Feda I; Owais, Arwa I; Kawaja, Wasan

    2016-01-01

    ABSTRACT Aim: To evaluate the effect of amorphous calcium phosphate (ACP)-containing pit and fissure sealant on inhibition of enamel demineralization in vitro. Materials and methods: Enamel specimens (n = 75) were prepared using freshly extracted noncarious human third molars. Box-shaped cavities (8 × 2 × 2 mm) on the buccal or lingual surfaces were prepared and restored with resin-based sealant (Concise™), ACP-containing sealant (Aegis®) or fluoride-containing sealant (Conseal-F™). The sampl...

  15. Fiber optic backscatter spectroscopic sensor to monitor enamel demineralization and remineralization in vitro

    OpenAIRE

    Kishen, Anil; Shrestha, Annie; Rafique, Adeela

    2008-01-01

    In this study, a Fiber Optic Backscatter Spectroscopic Sensor (FOBSS) is used to monitor demineralization and remineralization induced changes in the enamel. A bifurcated fiber optic backscatter probe connected to a visible light source and a high resolution spectrophotometer was used to acquire the backscatter light spectrum from the tooth surface. The experiments were conducted in two parts. In Part 1, experiments were carried out using fiber optic backscatter spectroscopy on (1) sound enam...

  16. Pursing Contamination Detection on Aircraft CFRP Surfaces By Artificial Olfaction Techniques

    Science.gov (United States)

    De Vito, Saverio; Massera, Ettore; Fattoruso, Grazia; Miglietta, Maria Lucia; Di Francia, Girolamo

    2011-09-01

    Carbon Fiber Reinforced Polymer (CFRP) structures can be easily bonded via adhesive assembly procedures but their cleanliness is of fundamental importance to ensure the strength of the adhesive bonding. Actually, surface contamination by several aeronautics fluids eventually results in weak or kissing bonds. The goal of our research work is to investigate solid state chemical sensors and artificial olfaction techniques (AO) for the detection of CFRP surface contamination by aeronautic fluids. This result will allow the implementation of an instrumental NDT procedure for CFRP surface cleanliness assessment prior to bonding. Herein, results of our first experimental setup, based on the use of an array of polymer sensors for the detection of aeronautic fluids contamination, are presented.

  17. Selective removal of demineralized enamel using a CO2 laser coupled with near-IR reflectance imaging

    Science.gov (United States)

    Tom, Henry; Chan, Kenneth H.; Saltiel, Daniel; Fried, Daniel

    2015-02-01

    Detection and diagnosis of early dental caries lesions can be difficult due to variable tooth coloration, staining of the teeth and poor contrast between sound and demineralized enamel. These problems can be overcome by using near-infrared (NIR) imaging. Previous studies have demonstrated that lasers can be integrated with NIR imaging devices, allowing image-guided ablation. The aim of this study was to demonstrate that NIR light at 1500 - 1700 nm can be used to guide a 9.3-μm CO2 laser for the selective ablation of early demineralization on tooth occlusal surfaces. The occlusal surfaces of ten sound human molars were used in this in-vitro study. Shallow simulated caries lesions of varying depth and position were produced on tooth occlusal surfaces using a demineralization solution. Sequential NIR reflectance images at 1500 - 1700 nm were used to guide the laser for selective ablation of the lesion areas. Digital microscopy and polarization sensitive optical coherence tomography (PS-OCT) were used to assess the selectivity of removal. This study demonstrates that high contrast NIR reflectance images can be used for the image-guided laser ablation of early demineralization from tooth occlusal surfaces.

  18. Engineering interaction between bone marrow derived endothelial cells and electrospun surfaces for artificial vascular graft applications.

    Science.gov (United States)

    Ahmed, Furqan; Dutta, Naba K; Zannettino, Andrew; Vandyke, Kate; Choudhury, Namita Roy

    2014-04-14

    The aim of this investigation was to understand and engineer the interactions between endothelial cells and the electrospun (ES) polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) nanofiber surfaces and evaluate their potential for endothelialization. Elastomeric PVDF-HFP samples were electrospun to evaluate their potential use as small diameter artificial vascular graft scaffold (SDAVG) and compared with solvent cast (SC) PVDF-HFP films. We examined the consequences of fibrinogen adsorption onto the ES and SC samples for endothelialisation. Bone marrow derived endothelial cells (BMEC) of human origin were incubated with the test and control samples and their attachment, proliferation, and viability were examined. The nature of interaction of fibrinogen with SC and ES samples was investigated in detail using ELISA, XPS, and FTIR techniques. The pristine SC and ES PVDF-HFP samples displayed hydrophobic and ultrahydrophobic behavior and accordingly, exhibited minimal BMEC growth. Fibrinogen adsorbed SC samples did not significantly enhance endothelial cell binding or proliferation. In contrast, the fibrinogen adsorbed electrospun surfaces showed a clear ability to modulate endothelial cell behavior. This system also represents an ideal model system that enables us to understand the natural interaction between cells and their extracellular environment. The research reported shows potential of ES surfaces for artificial vascular graft applications. PMID:24564790

  19. Spin wave absorber generated by artificial surface anisotropy for spin wave device network

    Science.gov (United States)

    Kanazawa, Naoki; Goto, Taichi; Sekiguchi, Koji; Granovsky, Alexander B.; Takagi, Hiroyuki; Nakamura, Yuichi; Inoue, Mitsuteru

    2016-09-01

    Spin waves (SWs) have the potential to reduce the electric energy loss in signal processing networks. The SWs called magnetostatic forward volume waves (MSFVWs) are advantageous for networking due to their isotropic dispersion in the plane of a device. To control the MSFVW flow in a processing network based on yttrium iron garnet, we developed a SW absorber using artificial structures. The mechanical surface polishing method presented in this work can well control extrinsic damping without changing the SW dispersion of the host material. Furthermore, enhancement of the ferromagnetic resonance linewidth over 3 Oe was demonstrated.

  20. Photothermal radiometry and modulated luminescence examination of demineralized and remineralized dental lesions

    Energy Technology Data Exchange (ETDEWEB)

    Hellen, A; Mandelis, A [Center for Advanced Diffusion-Wave Technologies, University of Toronto, 5 King' s College Road, Toronto, Ontario, M5S 3G8 (Canada); Finer, Y, E-mail: mandelis@mie.utoronto.c [Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, Ontario, M5G 1G6 (Canada)

    2010-03-01

    Dental caries involves continuous challenges of acid-induced mineral loss and a counteracting process of mineral recovery. As an emerging non-destructive methodology, photothermal radiometry and modulated luminescence (PTR-LUM) has shown promise in measuring changes in tooth mineral content. Human molars (n=37) were subjected to demineralization in acid gel (pH 4.5, 10 days), followed by incubation in remineralisation solutions (pH 6.7, 4 weeks) without or with fluoride (1 or 1000 ppm). PTR-LUM frequency scans (1 Hz - 1 kHz) were performed prior to and during demineralization and remineralization treatments. Transverse Micro-Radiography (TMR) analysis followed at treatment conclusion. The non-fluoridated group exhibited opposite amplitude and phase trends to those of the highly fluoridated group: smaller phase lag and larger amplitude. These results point to a complex interplay between surface and subsurface processes during remineralization, confining the thermal-wave centroid toward the dominating layer.

  1. Influence of photo-activation source on enamel demineralization around restorative materials

    Directory of Open Access Journals (Sweden)

    Juliana de Oliveira Ferla

    2013-06-01

    Full Text Available This study evaluated the effects of the photoactivation source and restorative material on the development of caries-like lesions on human enamel after an in vitro pH challenge. Enamel cavities were prepared in 36 blocks, which were assigned to two groups according to the restorative material: resin-modified glass ionomer (RMGI and composite resin (CR. Samples were exposed to quartz-tungsten-halogen lamp, argon-ion laser, or light-emitting diode (n = 6. The Knoop microhardness (KHN values of the top surface of all materials were evaluated. Restored enamel blocks were thermocycled and subjected to 10 demineralization-remineralization cycles at 37°C. KHN analysis of the superficial enamel was performed by four indentations located 100 mm from the restoration margin. The material KHN was not affected by the photoactivation source. No significant difference in KHN was noted between CR and RMGI. The enamel surface around RMGI exhibited a higher KHN (272.8 KHN than the enamel around CR (93.3 KHN, regardless of the photoactivation source. Enamel demineralization around the dental restoration was not influenced by the photoactivation source. Less enamel demineralization was observed around the RMGI than around the CR restoration.

  2. Properties of the "Orgamax" osteoplastic material made of a demineralized allograft bone

    Science.gov (United States)

    Podorognaya, V. T.; Kirilova, I. A.; Sharkeev, Yu. P.; Uvarkin, P. V.; Zhelezny, P. A.; Zheleznaya, A. P.; Akimova, S. E.; Novoselov, V. P.; Tupikova, L. N.

    2016-08-01

    We investigated properties of the "Orgamax" osteoplastic material, which was produced from a demineralized bone, in the treatment of extensive caries, in particular chronic pulpitis of the permanent teeth with unformed roots in children. The "Orgamax" osteoplastic material consists of demineralized bone chips, a collagen additive, and antibiotics. The surface morphology of the "Orgamax" osteoplastic material is macroporous, with the maximum pore size of 250 µm, whereas the surface morphology of the major component of "Orgamax", demineralized bone chips, is microporous, with a pore size of 10-20 µm. Material "Orgamax" is used in the treatment of complicated caries, particularly chronic pulpitis of permanent teeth with unformed roots in children. "Orgamax" filling a formed cavity exhibits antimicrobial properties, eliminates inflammation in the dental pulp, and, due to its osteoconductive and osteoinductive properties, undergoes gradual resorption, stimulates regeneration, and provides replacement of the defect with newly formed tissue. The dental pulp viability is completely restored, which ensures the complete formation of tooth roots with root apex closure in the long-term period.

  3. Artificial Neural Network Modeling of Surface Roughness in Magnetic Abrasive Finishing Process

    Directory of Open Access Journals (Sweden)

    F. Djavanroodi

    2013-07-01

    Full Text Available Magnetic Abrasive Finishing (MAF is an advanced finishing process in which the cutting force is controlled by magnetic field and it provides a high level of surface finish and close tolerances for wide range of industrial application. In this study the parameter that affects surface roughness in MAF process on a brass shaft of CuZn37 have been examined experimentally. These parameters are: intensity of the magnetic field, work-piece velocity and finishing time. It has been shown that the intensity of magnetic field has the most effect on finishing process, a higher intensity in magnetic field, results in a higher change in surface roughness, increasing finishing time results in decreased surface roughness and a lower work-piece velocity leads to a lower surface roughness. Finally Artificial Neural Network (ANN prediction of surface roughness are carried out and compared with experiment. It was found that the coefficient of multiple determinations (R2-value between the experimental and ANN predicted data is equal to about 0.999, therefore, indicating the possibility of ANN as a strong tool in simulating and prediction of surface roughness in MAF process.

  4. Research on micro-structure and hemo-compatibility of the artificial heart valve surface

    International Nuclear Information System (INIS)

    In order to seek the method to improve the hemo-compatibility of artificial mechanical heart valve, the surface of rabbit's heart valve was observed using the scanning electron microscopy (SEM). The results showed that the dual-scale structure which consists of cobblestones-like structure of 8 μm in underside diameter and 3 μm in height, and the fine cilia of about 150 nm in diameter, was helpful to the hemo-compatibility of the heart valve. Therefore, the polydimethylsiloxane (PDMS) surface with hierarchical micro-structure was fabricated using femtosecond laser fabrication technique and soft lithography. At the same time, the tests of apparent contact angle and platelet adhesion on both smooth and textured PDMS surfaces were carried out to study their wettability and hemo-compatibility. The results demonstrated that the surface with textured structure displayed more excellent wettabililty and anti-coagulation property than that of smooth surface. The apparent contact angle of textured surface enhanced from 113.1 deg. to 163.6 deg. and the amount of adsorbed platelet on such surface was fewer, no distortion and no activation were found.

  5. Hybrid intelligence systems and artificial neural network (ANN approach for modeling of surface roughness in drilling

    Directory of Open Access Journals (Sweden)

    Ch. Sanjay

    2014-12-01

    Full Text Available In machining processes, drilling operation is material removal process that has been widely used in manufacturing since industrial revolution. The useful life of cutting tool and its operating conditions largely controls the economics of machining operations. Drilling is most frequently performed material removing process and is used as a preliminary step for many operations, such as reaming, tapping, and boring. Drill wear has a bad effect on the surface finish and dimensional accuracy of the work piece. The surface finish of a machined part is one of the most important quality characteristics in manufacturing industries. The primary objective of this research is the prediction of suitable parameters for surface roughness in drilling. Cutting speed, cutting force, and machining time were given as inputs to the adaptive fuzzy neural network and neuro-fuzzy analysis for estimating the values of surface roughness by using 2, 3, 4, and 5 membership functions. The best structures were selected based on minimum of summation of square with the actual values with the estimated values by artificial neural fuzzy inference system (ANFIS and neuro-fuzzy systems. For artificial neural network (ANN analysis, the number of neurons was selected from 1, 2, 3, … , 20. The learning rate was selected as .5 and .5 smoothing factor was used. The inputs were selected as cutting speed, feed, machining time, and thrust force. The best structures of neural networks were selected based on the criteria as the minimum of summation of square with the actual value of surface roughness. Drilling experiments with 10 mm size were performed at two cutting speeds and feeds. Comparative analysis has been done between the actual values and the estimated values obtained by ANFIS, neuro-fuzzy, and ANN analysis.

  6. Data fusion with artificial neural networks (ANN) for classification of earth surface from microwave satellite measurements

    Science.gov (United States)

    Lure, Y. M. Fleming; Grody, Norman C.; Chiou, Y. S. Peter; Yeh, H. Y. Michael

    1993-01-01

    A data fusion system with artificial neural networks (ANN) is used for fast and accurate classification of five earth surface conditions and surface changes, based on seven SSMI multichannel microwave satellite measurements. The measurements include brightness temperatures at 19, 22, 37, and 85 GHz at both H and V polarizations (only V at 22 GHz). The seven channel measurements are processed through a convolution computation such that all measurements are located at same grid. Five surface classes including non-scattering surface, precipitation over land, over ocean, snow, and desert are identified from ground-truth observations. The system processes sensory data in three consecutive phases: (1) pre-processing to extract feature vectors and enhance separability among detected classes; (2) preliminary classification of Earth surface patterns using two separate and parallely acting classifiers: back-propagation neural network and binary decision tree classifiers; and (3) data fusion of results from preliminary classifiers to obtain the optimal performance in overall classification. Both the binary decision tree classifier and the fusion processing centers are implemented by neural network architectures. The fusion system configuration is a hierarchical neural network architecture, in which each functional neural net will handle different processing phases in a pipelined fashion. There is a total of around 13,500 samples for this analysis, of which 4 percent are used as the training set and 96 percent as the testing set. After training, this classification system is able to bring up the detection accuracy to 94 percent compared with 88 percent for back-propagation artificial neural networks and 80 percent for binary decision tree classifiers. The neural network data fusion classification is currently under progress to be integrated in an image processing system at NOAA and to be implemented in a prototype of a massively parallel and dynamically reconfigurable Modular

  7. Structural analysis of heat-treated birch (Betule papyrifera) surface during artificial weathering

    Energy Technology Data Exchange (ETDEWEB)

    Huang Xianai [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Kocaefe, Duygu, E-mail: dkocaefe@uqac.ca [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Kocaefe, Yasar [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Boluk, Yaman [University of Alberta, 3-142 Markin/CNRL Natural Resources Engineering Facility, Edmonton, Alberta, T6G 2W2 (Canada); Krause, Cornelia [Universite du Quebec a Chicoutimi, 555, boul. de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer Investigate detailed structural changes of heat-treated wood due to weathering. Black-Right-Pointing-Pointer Identify connection between physical structural changes and chemical degradation. Black-Right-Pointing-Pointer Study effect of heat treatment conditions on weathering degradation process. - Abstract: Effect of artificial weathering on the surface structural changes of birch (Betule papyrifera) wood, heat-treated to different temperatures, was studied using the fluorescence microscopy and the scanning electron microscopy (SEM). Changes in the chemical structure of wood components were analyzed by FTIR in order to understand the mechanism of degradation taking place due to heat treatment and artificial weathering. The results are compared with those of the untreated (kiln-dried) birch. The SEM analysis results show that the effect of weathering on the cell wall of the untreated birch surface is more than that of heat-treated samples. The FTIR spectroscopy results indicate that lignin is the most sensitive component of heat-treated birch to the weathering degradation process. Elimination of the amorphous and highly crystallised cellulose is observed for both heat-treated and untreated wood during weathering. It is also observed that heat treatment increases the lignin and crystallised cellulose contents, which to some extent protects heat-treated birch against degradation due to weathering.

  8. Structural analysis of heat-treated birch (Betule papyrifera) surface during artificial weathering

    Science.gov (United States)

    Huang, Xianai; Kocaefe, Duygu; Kocaefe, Yasar; Boluk, Yaman; Krause, Cornélia

    2013-01-01

    Effect of artificial weathering on the surface structural changes of birch (Betule papyrifera) wood, heat-treated to different temperatures, was studied using the fluorescence microscopy and the scanning electron microscopy (SEM). Changes in the chemical structure of wood components were analyzed by FTIR in order to understand the mechanism of degradation taking place due to heat treatment and artificial weathering. The results are compared with those of the untreated (kiln-dried) birch. The SEM analysis results show that the effect of weathering on the cell wall of the untreated birch surface is more than that of heat-treated samples. The FTIR spectroscopy results indicate that lignin is the most sensitive component of heat-treated birch to the weathering degradation process. Elimination of the amorphous and highly crystallised cellulose is observed for both heat-treated and untreated wood during weathering. It is also observed that heat treatment increases the lignin and crystallised cellulose contents, which to some extent protects heat-treated birch against degradation due to weathering.

  9. Effects of Spatial Dispersion on Reflection from Mushroom-type Artificial Impedance Surfaces

    CERN Document Server

    Luukkonen, Olli; Yakovlev, Alexander B; Simovski, Constantin R; Nefedov, Igor S; Tretyakov, Sergei A

    2008-01-01

    Several recent works have emphasized the role of spatial dispersion in wire media, and demonstrated that arrays of parallel metallic wires may behave very differently from a uniaxial local material with negative permittivity. Here, we investigate using local and non-local homogenization methods the effect of spatial dispersion on reflection from the mushroom structure introduced by Sievenpiper. The objective of the paper is to clarify the role of spatial dispersion in the mushroom structure and demonstrate that under some conditions it is suppressed. The metamaterial substrate, or metasurface, is modeled as a wire medium covered with an impedance surface. Surprisingly, it is found that in such configuration the effects of spatial dispersion may be nearly suppressed when the slab is electrically thin, and that the wire medium can be modeled very accurately using a local model. This result paves the way for the design of artificial surfaces that exploit the plasmonic-type response of the wire medium slab.

  10. Integrated control of the cooling system and surface openings using the artificial neural networks

    International Nuclear Information System (INIS)

    This study aimed at suggesting an indoor temperature control method that can provide a comfortable thermal environment through the integrated control of the cooling system and the surface openings. Four control logic were developed, employing different application levels of rules and artificial neural network models. Rule-based control methods represented the conventional approach while ANN-based methods were applied for the predictive and adaptive controls. Comparative performance tests for the conventional- and ANN-based methods were numerically conducted for the double-skin-facade building, using the MATLAB (Matrix Laboratory) and TRNSYS (Transient Systems Simulation) software, after proving the validity by comparing the simulation and field measurement results. Analysis revealed that the ANN-based controls of the cooling system and surface openings improved the indoor temperature conditions with increased comfortable temperature periods and decreased standard deviation of the indoor temperature from the center of the comfortable range. In addition, the proposed ANN-based logic effectively reduced the number of operating condition changes of the cooling system and surface openings, which can prevent system failure. The ANN-based logic, however, did not show superiority in energy efficiency over the conventional logic. Instead, they have increased the amount of heat removal by the cooling system. From the analysis, it can be concluded that the ANN-based temperature control logic was able to keep the indoor temperature more comfortably and stably within the comfortable range due to its predictive and adaptive features. - Highlights: • Integrated rule-based and artificial neural network based logics were developed. • A cooling device and surface openings were controlled in an integrated manner. • Computer simulation method was employed for comparative performance tests. • ANN-based logics showed the advanced features of thermal environment. • Rule

  11. LiNbO 3 Coating on Concrete Surface: A New and Environmentally Friendly Route for Artificial Photosynthesis

    OpenAIRE

    Nath, Ranjit K.; M. F. M .Zain; Kadhum, Abdul Amir H.

    2013-01-01

    The addition of a photocatalyst to ordinary building materials such as concrete creates environmentally friendly materials by which air pollution or pollution of the surface can be diminished. The use of LiNbO3 photocatalyst in concrete material would be more beneficial since it can produce artificial photosynthesis in concrete. In these research photoassisted solid-gas phases reduction of carbon dioxide (artificial photosynthesis) was performed using a photocatalyst, LiNbO3, coated on concre...

  12. Enamel and dentine demineralization by a combination of starch and sucrose in a biofilm - caries model.

    Science.gov (United States)

    Botelho, Juliana Nunes; Villegas-Salinas, Mario; Troncoso-Gajardo, Pía; Giacaman, Rodrigo Andrés; Cury, Jaime Aparecido

    2016-05-20

    Sucrose is the most cariogenic dietary carbohydrate and starch is considered non-cariogenic for enamel and moderately cariogenic for dentine. However, the cariogenicity of the combination of starch and sucrose remains unclear. The aim of this study was to evaluate the effect of this combination on Streptococcus mutans biofilm composition and enamel and dentine demineralization. Biofilms of S. mutans UA159 were grown on saliva-coated enamel and dentine slabs in culture medium containing 10% saliva. They were exposed (8 times/day) to one of the following treatments: 0.9% NaCl (negative control), 1% starch, 10% sucrose, or 1% starch and 10% sucrose (starch + sucrose). To simulate the effect of human salivary amylase on the starch metabolization, the biofilms were pretreated with saliva before each treatment and saliva was also added to the culture medium. Acidogenicity of the biofilm was estimated by evaluating (2 times/day) the culture medium pH. After 4 (dentine) or 5 (enamel) days of growth, biofilms (n = 9) were individually collected, and the biomass, viable microorganism count, and polysaccharide content were quantified. Dentine and enamel demineralization was assessed by determining the percentage of surface hardness loss. Biofilms exposed to starch + sucrose were more acidogenic and caused higher demineralization (p < 0.0001) on either enamel or dentine than those exposed to each carbohydrate alone. The findings suggest that starch increases the cariogenic potential of sucrose. PMID:27223133

  13. Fluoride varnishes with calcium glycerophosphate: fluoride release and effect on in vitro enamel demineralization

    Directory of Open Access Journals (Sweden)

    Thiago Saads CARVALHO

    2015-01-01

    Full Text Available The aims of this study were (1 to assess the amount of fluoride (F released from varnishes containing calcium glycerophosphate (CaGP and (2 to assess the effect of the experimental varnishes on in vitro demineralization. Six test groups using 5 varnishes: base varnish (no active ingredients; Duraphat® (2.26% NaF; Duofluorid® (5.63% NaF/CaF2; experimental varnish 1 (1% CaGP/5.63% NaF/CaF2; experimental varnish 2 (5% CaGP/5.63% NaF/CaF2; and no varnish were set up. In stage 1, 60 acrylic blocks were randomly distributed into 6 groups (n = 10. Then 300 µg of each varnish was applied to each block. The blocks were immersed in deionized water, which was changed after 1, 8, 12, 24, 48 and 72 hours. Fluoride concentration in the water was analyzed using a fluoride electrode. In stage 2, 60 bovine enamel samples were distributed into 6 groups (n = 10, and treated with 300 µg of the respective varnish. After 6 h the varnish was removed and the samples were subjected to a 7-day in vitro pH cycle (6 h demineralization/18 h remineralization per day. The demineralization was measured using surface hardness. The results showed that both experimental varnishes released more fluoride than Duofluorid® and Duraphat® (p < 0.05, but Duraphat® showed the best preventive effect by decreasing enamel hardness loss (p < 0.05. Therefore, we conclude that even though (1 the experimental varnishes containing CaGP released greater amounts of F, (2 they did not increase in the preventive effect against enamel demineralization.

  14. The effect of fluoride toothpaste on root dentine demineralization progression: a pilot study

    Directory of Open Access Journals (Sweden)

    Juliana Nunes Botelho

    2014-02-01

    Full Text Available The anticaries effect of fluoride (F toothpaste containing 1100 µg F/g in reducing enamel demineralization is well established, but its effect on dentine has not been extensively studied. Furthermore, it has been shown that toothpaste containing a high F concentration is necessary to remineralize root dentine lesions, suggesting that a 1100 µg F/g concentration might not be high enough to reduce root dentine demineralization, particularly when dentine is subjected to a high cariogenic challenge. Thus, the aim of this pilot study was to evaluate in situ the effect of F toothpaste, at a concentration of 1100 µg F/g, on dentine demineralization. In a crossover and double-blind study, conducted in two phases of 14 days, six volunteers wore a palatal appliance containing four slabs of bovine root dentine whose surface hardness (SH was previously determined and to which a 10% sucrose solution was applied extra-orally 8×/day. Volunteers used a non-F toothpaste (negative control or F toothpaste (1100 µg F/g, NaF/SiO2 three times a day. On the 10th and 14th days of each phase, two slabs were collected and SH was determined again. Dentine demineralization was assessed as percentage of SH loss (%SHL. The effect of toothpaste was significant, showing lower %SHL for the F toothpaste group (42.0 ± 9.7 compared to the non-F group (62.0 ± 6.4; p 0.05. This pilot study suggests that F toothpaste at 1100 µg F/g is able to decrease dentine caries even under a high cariogenic challenge of biofilm accumulation and sugar exposure.

  15. Release of beryllium from mineral ores in artificial lung and skin surface fluids.

    Science.gov (United States)

    Duling, Matthew G; Stefaniak, Aleksandr B; Lawrence, Robert B; Chipera, Steve J; Virji, M Abbas

    2012-06-01

    Exposure to some manufactured beryllium compounds via skin contact or inhalation can cause sensitization. A portion of sensitized persons who inhale beryllium may develop chronic beryllium disease (CBD). Little is understood about exposures to naturally occurring beryllium minerals. The purpose of this study was to assess the bioaccessibility of beryllium from bertrandite ore. Dissolution of bertrandite from two mine pits (Monitor and Blue Chalk) was evaluated for both the dermal and inhalation exposure pathways by determining bioaccessibility in artificial sweat (pH 5.3 and pH 6.5), airway lining fluid (SUF, pH 7.3), and alveolar macrophage phagolysosomal fluid (PSF, pH 4.5). Significantly more beryllium was released from Monitor pit ore than Blue Chalk pit ore in artificial sweat buffered to pH 5.3 (0.88 ± 0.01% vs. 0.36 ± 0.00%) and pH 6.5 (0.09 ± 0.00% vs. 0.03 ± 0.01%). Rates of beryllium released from the ores in artificial sweat were faster than previously measured for manufactured forms of beryllium (e.g., beryllium oxide), known to induce sensitization in mice. In SUF, levels of beryllium were below the analytical limit of detection. In PSF, beryllium dissolution was biphasic (initial rapid diffusion followed by latter slower surface reactions). During the latter phase, dissolution half-times were 1,400 to 2,000 days, and rate constants were ~7 × 10(-10) g/(cm(2)·day), indicating that bertrandite is persistent in the lung. These data indicate that it is prudent to control skin and inhalation exposures to bertrandite dusts. PMID:21866318

  16. Egg-in-cube: design and fabrication of a novel artificial eggshell with functionalized surface.

    Directory of Open Access Journals (Sweden)

    Wenjing Huang

    Full Text Available An eggshell is a porous microstructure that regulates the passage of gases to allow respiration. The chick embryo and its circulatory system enclosed by the eggshell has become an important model for biomedical research such as the control of angiogenesis, cancer therapy, and drug delivery test, because the use of embryo is ethically acceptable and it is inexpensive and small. However, chick embryo and extra-embryonic blood vessels cannot be accessed freely and has poor observability because the eggshell is tough and cannot be seen through, which limits its application. In this study, a novel artificial eggshell with functionalized surface is proposed, which allows the total amount of oxygen to pass into the egg for the chick embryo culturing and has high observability and accessibility for embryo manipulation. First, a 40-mm enclosed cubic-shaped eggshell consisting of a membrane structure and a rigid frame structure is designed, and then the threshold of the membrane thickness suitable for the embryo survival is figured out according to the oxygen-permeability of the membrane structure. The designed artificial eggshell was actually fabricated by using polydimethylsiloxane (PDMS and polycarbonate (PC in the current study. Using the fabricated eggshell, chick embryo and extra-embryonic blood vessels can be observed from multiple directions. To test the effectiveness of the design, the cubic eggshells were used to culture chick embryos and survivability was confirmed when PDMS membranes with adequate oxygen permeability were used. Since the surface of the eggshell is transparent, chick embryo tissue development could be observed during the culture period. Additionally, the chick embryo tissues could be accessed and manipulated from outside the cubic eggshell, by using mechanical tools without breakage of the eggshell. The proposed "Egg-in-Cube" with functionalized surface has great potential to serve as a promising platform for biomedical

  17. Surface Passivation of ZrO2 Artificial Dentures by Magnetized Coaxial Plasma deposition

    Science.gov (United States)

    Arai, Soya; Kurumi, Satoshi; Matsuda, Ken-Ichi; Suzuki, Kaoru; Hara, Katsuya; Kato, Tatsuya; Asai, Tomohiko; Hirose, Hideharu; Masutani, Shigeyuki; Nihon University Team

    2015-09-01

    Recent growth and fabrication technologies for functional materials have been greatly contributed to drastic development of oral surgery field. Zirconia based ceramics is expected to utilize artificial dentures because these ceramics have good biocompatibility, high hardness and aesthetic attractively. However, to apply these ceramics to artificial dentures, this denture is removed from a dental plate because of weakly bond. For improving this problem, synthesis an Al passivation-layer on the ceramics for bonding with these dental items is suitable. In order to deposit the passivation layer, we focused on a magnetized coaxial plasma deposition (MCPD). The greatest characteristic of MCPD is that high-melting point metal can be deposited on various substrates. Additionally, adhesion force between substrate and films deposited by the MCPD is superior to it of general deposition methods. In this study, we have reported on the growth techniques of Al films on ZrO2 for contributing to oral surgery by the MCPD. Surface of deposited films shows there were some droplets and thickness of it is about 200 nm. Thickness is increased to 500 nm with increasing applied voltage.

  18. Surface roughness of Ti6Al4V after heat treatment evaluated by artificial neural networks

    International Nuclear Information System (INIS)

    The study examines how, using wire electrical discharge machining (WEDM), the microstructural, mechanical and conductivity characteristics of the titanium alloy Ti6Al4V are changed as a result of heat treatment and the effect they have on machinability. Scanning electron microscope (SEM), optical microscope and X-ray diffraction (XRD) examinations were performed to determine various characteristics and additionally related microhardness and conductivity measurements were conducted. L18 Taquchi test design was performed with three levels and six different parameters to determine the effect of such alterations on its machinability using WEDM and post-processing surface roughness (Ra) values were determined. Micro-changes were ensured successfully by using heat treatments. Results obtained with the optimization technique of artificial neural network (ANN) presented minimum surface roughness. Values obtained by using response surface method along with this equation were completely comparable with those achieved in the experiments. The best surface roughness value was obtained from sample D which had a tempered martensite structure.

  19. Surface roughness of Ti6Al4V after heat treatment evaluated by artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Altug, Mehmet [Inonu Univ., Malataya (Turkey). Dept. of Machine and Metal Technologies; Erdem, Mehmet; Bozkir, Oguz [Inonu Univ., Malataya (Turkey); Ozay, Cetin [Univ. of Firat Elazig (Turkey). Faculty of Tech. Education

    2016-05-01

    The study examines how, using wire electrical discharge machining (WEDM), the microstructural, mechanical and conductivity characteristics of the titanium alloy Ti6Al4V are changed as a result of heat treatment and the effect they have on machinability. Scanning electron microscope (SEM), optical microscope and X-ray diffraction (XRD) examinations were performed to determine various characteristics and additionally related microhardness and conductivity measurements were conducted. L{sub 18} Taquchi test design was performed with three levels and six different parameters to determine the effect of such alterations on its machinability using WEDM and post-processing surface roughness (Ra) values were determined. Micro-changes were ensured successfully by using heat treatments. Results obtained with the optimization technique of artificial neural network (ANN) presented minimum surface roughness. Values obtained by using response surface method along with this equation were completely comparable with those achieved in the experiments. The best surface roughness value was obtained from sample D which had a tempered martensite structure.

  20. Application of artificial neural networks for response surface modelling in HPLC method development

    Directory of Open Access Journals (Sweden)

    Mohamed A. Korany

    2012-01-01

    Full Text Available This paper discusses the usefulness of artificial neural networks (ANNs for response surface modelling in HPLC method development. In this study, the combined effect of pH and mobile phase composition on the reversed-phase liquid chromatographic behaviour of a mixture of salbutamol (SAL and guaiphenesin (GUA, combination I, and a mixture of ascorbic acid (ASC, paracetamol (PAR and guaiphenesin (GUA, combination II, was investigated. The results were compared with those produced using multiple regression (REG analysis. To examine the respective predictive power of the regression model and the neural network model, experimental and predicted response factor values, mean of squares error (MSE, average error percentage (Er%, and coefficients of correlation (r were compared. It was clear that the best networks were able to predict the experimental responses more accurately than the multiple regression analysis.

  1. Artificial Neural Networks for Surface Roughness Prediction when Face Milling Al 7075-T7351

    Science.gov (United States)

    Muñoz-Escalona, Patricia; Maropoulos, Paul G.

    2010-03-01

    In this work, different artificial neural networks (ANN) are developed for the prediction of surface roughness ( R a ) values in Al alloy 7075-T7351 after face milling machining process. The radial base (RBNN), feed forward (FFNN), and generalized regression (GRNN) networks were selected, and the data used for training these networks were derived from experiments conducted using a high-speed milling machin/span>e. The Taguchi design of experiment was applied to reduce the time and cost of the experiments. From this study, the performance of each ANN used in this research was measured with the mean square error percentage and it was observed that FFNN achieved the best results. Also the Pearson correlation coefficient was calculated to analyze the correlation between the five inputs (cutting speed, feed per tooth, axial depth of cut, chip’s width, and chip’s thickness) selected for the network with the selected output (surface roughness). Results showed a strong correlation between the chip thickness and the surface roughness followed by the cutting speed.

  2. Comparison of polynomial approximations and artificial neural nets for response surfaces in engineering optimization

    Science.gov (United States)

    Carpenter, William C.

    1991-01-01

    Engineering optimization problems involve minimizing some function subject to constraints. In areas such as aircraft optimization, the constraint equations may be from numerous disciplines such as transfer of information between these disciplines and the optimization algorithm. They are also suited to problems which may require numerous re-optimizations such as in multi-objective function optimization or to problems where the design space contains numerous local minima, thus requiring repeated optimizations from different initial designs. Their use has been limited, however, by the fact that development of response surfaces randomly selected or preselected points in the design space. Thus, they have been thought to be inefficient compared to algorithms to the optimum solution. A development has taken place in the last several years which may effect the desirability of using response surfaces. It may be possible that artificial neural nets are more efficient in developing response surfaces than polynomial approximations which have been used in the past. This development is the concern of the work.

  3. Regression-Based Artificial Neural Network Methodology in Response Surface Methodology

    Institute of Scientific and Technical Information of China (English)

    何桢; 肖粤翔

    2004-01-01

    Response surface methodology (RSM) is an important tool for process parameter optimization, robust design and other quality improvement efforts. When the relationship between influential input variables and output response is very complex, it' s hard to find the real response surface using RSM. In recent years artificial neural network(ANN) has been used in RSM. But the classical ANN does not work well under the constraints of real applications. An algorithm of regression-based ANN(R-ANN) is proposed in this paper, which is a supplement to the classical ANN methodology. It makes network closer to the response surface, so that training time is reduced and robustness is strengthened. The procedure of improving ANN by regressions is described and the comparisons among R-ANN, RSM and classical ANN are computed graphically in three examples. Our research shows that the R-ANN methodology is a good supplement to the RSM and classical ANN methodology,which can yield lower standard error of prediction under conditions that the scope of experiment is rigidly restricted.

  4. Enamel Demineralization Prevention during Fixed Orthodontic Treatment and Remineralization Strategies

    Institute of Scientific and Technical Information of China (English)

    SUN Xin-hua; Wayne J Sampson

    2007-01-01

    Preventing enamel demineralization and remineralization of orthodontic patients is important and it differs from other dental patients.Oral hygiene education and oral examination is essential to prevent enamel demineralization,and dietary education or control of sugar intake should not be ignored during fixed orthodontic treatment.Laser irradiation is a noteworthy method to prevent enamel mineralization.Products containing fluoride and fluoride released not only can be used to prevent demineralization but also have the ability of remineralization during orthodontic treatment.Oral hygiene products containing casein-phosphopeptide amorphous calcium phosphate (CPP-ACP) have been demonstrated to have the ability of remineralization such as sugar-free chewing gum added CPP-ACP,lozenges containing CPP-AGP and milk protein casein tabilized by phosphopeptides.

  5. Anisotropic surface roughness enhances the bending response of ionic polymer-metal composite (IPMC) artificial muscles

    Science.gov (United States)

    Stoimenov, Boyko L.; Rossiter, Jonathan M.; Mukai, Toshiharu

    2007-01-01

    Demands from the fields of bio-medical engineering and biologically-inspired robotics motivate a growing interest in actuators with properties similar to biological muscle, including ionic polymer-metal composites (IPMC), the focus of this study. IPMC actuators consist of an ion-conductive polymer membrane, coated with thin metal electrodes on both sides and bend when voltage is applied. Some of the advantages of IPMC actuators are their softness, lack of moving parts, easy miniaturization, light weight and low actuation voltage. When used in bio-mimetic robotic applications, such as a snake-like swimming robot, locomotion speed can be improved by increasing the bending amplitude. However, it cannot be improved much by increasing the driving voltage, because of water electrolysis. To enhance the bending response of IPMCs we created a "preferred" bending direction by anisotropic surface modification. Introduction of anisotropic roughness with grooves across the length of the actuator improved the bending response by a factor of 2.1. Artificially introduced cracks on the electrodes in direction, in which natural cracks form by bending, improved bending response by a factor of 1.6. Anisotropic surface modification is an effective method to enhance the bending response of IPMC actuators and does not compromise their rigidity under loads perpendicular to the bending plane.

  6. Effects of artificial tears on rabbit ocular surface healing after exposure to benzalkonium chloride.

    Science.gov (United States)

    Zhang, Yuqiu; Cao, Hong; Lin, Tong; Gong, Lan

    2016-10-01

    The aim of the study was to observe the effect of different artificial tears on healing the drug-induced keratopathy. To this aim, 64 rabbits received topical administration of 0.01% benzalkonium chloride to establish models and were divided into four groups. The control group received ocular saline solution (Saline), while the others were treated with Refresh Plus® (RF), Hycosan® (H) and Systane® Ultra (SU). Surface abnormalities were examined daily using slit-lamp. Fluorescein staining, histopathological and transmission electron microscopic (TEM) examination were performed at day 0, 2 weeks, and 1 and 2 months. A significant difference was observed between RF and SU, but not between H and SU at 2 weeks. TEM examination revealed new microvilli close to the cavity surface, and the number of microvilli in SU was greater than in H at 2 weeks and 1 month. Based on the results, the effect in the SU group was the most significant. Eye drops with nontoxic preservative such as SU are an alternative to treat drug-induced keratopathy. PMID:26890221

  7. Surface electrocardiogram reconstruction from intracardiac electrograms using a dynamic time delay artificial neural network

    Science.gov (United States)

    Porée, Fabienne; Kachenoura, Amar; Carrault, Guy; Dal Molin, Renzo; Mabo, Philippe; Hernandez, Alfredo I.

    2013-01-01

    The study proposes a method to facilitate the remote follow-up of patients suffering from cardiac pathologies and treated with an implantable device, by synthesizing a 12-lead surface ECG from the intracardiac electrograms (EGM) recorded by the device. Two methods (direct and indirect), based on dynamic Time Delay artificial Neural Networks (TDNN) are proposed and compared with classical linear approaches. The direct method aims to estimate 12 different transfer functions between the EGM and each surface ECG signal. The indirect method is based on a preliminary orthogonalization phase of the available EGM and ECG signals, and the application of the TDNN between these orthogonalized signals, using only three transfer functions. These methods are evaluated on a dataset issued from 15 patients. Correlation coefficients calculated between the synthesized and the real ECG show that the proposed TDNN methods represent an efficient way to synthesize 12-lead ECG, from two or four EGM and perform better than the linear ones. We also evaluate the results as a function of the EGM configuration. Results are also supported by the comparison of extracted features and a qualitative analysis performed by a cardiologist. PMID:23086502

  8. Inhibition of enamel demineralization by buffering effect of S-PRG filler-containing dental sealant.

    Science.gov (United States)

    Kaga, Masayuki; Kakuda, Shinichi; Ida, Yusuke; Toshima, Hirokazu; Hashimoto, Masanori; Endo, Kazuhiko; Sano, Hidehiko

    2014-02-01

    The buffering capacity and inhibitory effects on enamel demineralization of two commercially available dental sealants were evaluated in this study. The effects of filler particles were also examined. Disks of enamel and cured sealant materials of BeautiSealant (silica or S-PRG filler) or Teethmate F-1 were incubated in lactic acid solutions (pH 4.0) for 1-6 d. The pH changes and amounts of ions released in the solutions were assessed, and enamel surfaces were observed using a scanning electron microscope. The pH of the solution with BeautiSealant (S-PRG filler) was neutralized from pH 4.0 to pH 6.1 (after incubation for 1 d) and from pH 4.0 to pH 6.7 (after incubation for 6 d). In addition, no release of calcium ions was detected and the enamel surface was morphologically intact in scanning electron microscopy images. However, the pH of the solution with Teethmate F-1 remained below pH 4.0 during incubation from days 1 to 6. Calcium release was increased in solutions up to and after 6 d of incubation. Scanning electron microscopy images showed that the structures of hydroxyapatite rods were exposed at the specimen surfaces as a result of demineralization. Ions released from S-PRG filler-containing dental sealant rapidly buffered the lactic acid solution and inhibited enamel demineralization. PMID:24372898

  9. Combination effect of fluoride dentifrices and varnish on deciduous enamel demineralization

    Directory of Open Access Journals (Sweden)

    Alessandra Gatti

    2011-10-01

    Full Text Available The aim of this study was to evaluate the anticaries potential of 500 or 1100 ppm F dentifrices combined with fluoride varnish using a pH-cycling regimen. Seventy primary canines were covered with nail polish, leaving a 4×4 mm window on their buccal surface, and randomly assigned into 7 groups (n = 10: S: sound enamel not submitted to the pH-cycling regimen or treatment; N: negative control, submitted to the pH-cycling regimen without any treatment; D1 and D2: subjected to the pH-cycling regimen and treated twice daily with 1100 or 500 ppm F dentifrice, respectively; VF: fluoride varnish (subjected to F-varnish before and in the middle of the pH-cycling regimen; and VF+D1 and VF+D2. After 10 days, the teeth were sectioned, and enamel demineralization was assessed by cross-sectional hardness at different distances from the dental surface. Data were analyzed using a two-way ANOVA followed by Tukey's test. Dentifrice with 1100 ppm F and the combination of F-varnish with the dentifrices significantly reduced enamel demineralization compared with the negative control (p 0.05. The effect of combining F-varnish with the dentifrices was not greater than the effect of the dentifrices alone (p < 0.05. The data suggest that the combination of F-varnish with dentifrices containing 500 and 1100 ppm F is not more effective in reducing demineralization in primary teeth than the isolated effect of dentifrice containing 1100 ppm F.

  10. Gain-Enhanced On-Chip Antenna Utilizing Artificial Magnetic Conductor Reflecting Surface at 94 GHz

    KAUST Repository

    Nafe, Mahmoud

    2015-08-04

    Nowadays, there is a growing demand for high frequency-bandwidth mm-wave (30-300 GHz) electronic wireless transceiver systems to support applications such as high data-rate wireless communication and high resolution imaging. Such mm-wave systems are becoming more feasible due to the extreme transistor downscaling in silicon-based integrated circuits, which enabled densely-integrated high-speed elec- tronics operating up to more than 100 GHz with low fabrication cost. To further enhance system integrability, it is required to implement all wireless system compo- nents on the chip. Presently, the last major barrier to true System-on-Chip (SoC) realization is the antenna implementation on the silicon chip. Although at mm-wave frequencies the antenna size becomes small enough to fit on chip, the antenna performance is greatly deteriorated due the high conductivity and high relative permittivity of the silicon substrate. The negative e↵ects of the silicon substrate could be avoided by using a metallic reflecting surface on top of silicon, which e↵ectively isolates the antenna from the silicon. However, this approach has the shortcoming of having to implement the antenna on the usually very thin silicon oxide layer of a typical CMOS fabrication process (10’s of μm). This forces the antenna to be in a very close proximity (less than one hundredth of a wavelength) to the reflecting surface. In this regime, the use of conventional metallic reflecting surface for silicon shielding has severe e↵ects on the antenna performance as it tends to reduce the antenna radiation resistance resulting in most of the energy being absorbed rather than radiated. In this work, the use of specially patterned reflecting surfaces for improving on- chip antenna performance is investigated. By using a periodic metallic surface on top of a grounded substrate, the structure can mimic the behavior of a perfect mag- netic conductor, hence called Artificial Magnetic Conductor (AMC) surface

  11. Surface properties of multilayered, acrylic resin artificial teeth after immersion in staining beverages

    Directory of Open Access Journals (Sweden)

    Karin Hermana NEPPELENBROEK

    2015-08-01

    Full Text Available AbstractObjective To evaluate the effect of staining beverages (coffee, orange juice, and red wine on the Vickers hardness and surface roughness of the base (BL and enamel (EL layers of improved artificial teeth (Vivodent and Trilux.Material and Methods Specimens (n=8 were stored in distilled water at 37°C for 24 h and then submitted to the tests. Afterwards, specimens were immersed in one of the staining solutions or distilled water (control at 37°C, and the tests were also performed after 15 and 30 days of immersion. Data were analyzed using 3-way ANOVA and Tukey’s test (α=0.05.Results Vivodent teeth exhibited a continuous decrease (p0.15, but red wine and orange juice continuously reduced hardness values (p0.06.Conclusions Hardness of the two brands of acrylic teeth was reduced by all staining beverages, mainly for red wine. Roughness of both layers of the teeth was not affected by long-term immersion in the beverages.

  12. Artificial Intelligence Mechanisms on Interactive Modified Simplex Method with Desirability Function for Optimising Surface Lapping Process

    Directory of Open Access Journals (Sweden)

    Pongchanun Luangpaiboon

    2014-01-01

    Full Text Available A study has been made to optimise the influential parameters of surface lapping process. Lapping time, lapping speed, downward pressure, and charging pressure were chosen from the preliminary studies as parameters to determine process performances in terms of material removal, lap width, and clamp force. The desirability functions of the-nominal-the-best were used to compromise multiple responses into the overall desirability function level or D response. The conventional modified simplex or Nelder-Mead simplex method and the interactive desirability function are performed to optimise online the parameter levels in order to maximise the D response. In order to determine the lapping process parameters effectively, this research then applies two powerful artificial intelligence optimisation mechanisms from harmony search and firefly algorithms. The recommended condition of (lapping time, lapping speed, downward pressure, and charging pressure at (33, 35, 6.0, and 5.0 has been verified by performing confirmation experiments. It showed that the D response level increased to 0.96. When compared with the current operating condition, there is a decrease of the material removal and lap width with the improved process performance indices of 2.01 and 1.14, respectively. Similarly, there is an increase of the clamp force with the improved process performance index of 1.58.

  13. Long-term hip simulator testing of the artificial hip joint bearing surface grafted with biocompatible phospholipid polymer.

    Science.gov (United States)

    Moro, Toru; Takatori, Yoshio; Kyomoto, Masayuki; Ishihara, Kazuhiko; Hashimoto, Masami; Ito, Hideya; Tanaka, Takeyuki; Oshima, Hirofumi; Tanaka, Shigeyuki; Kawaguchi, Hiroshi

    2014-03-01

    To prevent periprosthetic osteolysis and subsequent aseptic loosening of artificial hip joints, we recently developed a novel acetabular highly cross-linked polyethylene (CLPE) liner with graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) on its surface. We investigated the wear resistance of the poly(MPC) (PMPC)-grafted CLPE liner during 20 million cycles in a hip joint simulator. We extended the simulator test of one liner to 70 million cycles to investigate the long-term durability of the grafting. Gravimetric, surface, and wear particle analyses revealed that PMPC grafting onto the CLPE liner surface markedly decreased the production of wear particles and showed that the effect of PMPC grafting was maintained through 70 million cycles. We believe that PMPC grafting can significantly improve the wear resistance of artificial hip joints. PMID:24249706

  14. APF and dentifrice effect on root dentin demineralization and biofilm

    NARCIS (Netherlands)

    G.C. Vale; C.P.M. Tabchoury; A.A. Del Bel Cury; L.M.A. Tenuta; J.M. ten Cate; J.A. Cury

    2011-01-01

    Because dentin is more caries-susceptible than enamel, its demineralization may be more influenced by additional fluoride (F). We hypothesized that a combination of professional F, applied as acidulated phosphate F (APF), and use of 1100-ppm-F dentifrice would provide additional protection for denti

  15. Selective removal of demineralization using near infrared cross polarization reflectance and a carbon dioxide laser

    Science.gov (United States)

    Chan, Kenneth H.; Fried, Daniel

    2012-01-01

    Lasers can ablate/remove tissue in a non-contact mode of operation and a pulsed laser beam does not interfere with the ability to image the tooth surface, therefore lasers are ideally suited for integration with imaging devices for image-guided ablation. Laser energy can be rapidly and efficiently delivered to tooth surfaces using a digitally controlled laser beam scanning system for precise and selective laser ablation with minimal loss of healthy tissues. Under the appropriate irradiation conditions such laser energy can induce beneficial chemical and morphological changes in the walls of the drilled cavity that can increase resistance to further dental decay and produce surfaces with enhanced adhesive properties to restorative materials. Previous studies have shown that images acquired using near-IR transillumination, optical coherence tomography and fluorescence can be used to guide the laser for selective removal of demineralized enamel. Recent studies have shown that NIR reflectance measurements at 1470-nm can be used to obtain images of enamel demineralization with very high contrast. The purpose of this study was to demonstrate that image guided ablation of occlusal lesions can be successfully carried out using a NIR reflectance imaging system coupled with a carbon dioxide laser operating at 9.3-μm with high pulse repetition rates.

  16. Artificial urushi.

    Science.gov (United States)

    Kobayashi, S; Uyama, H; Ikeda, R

    2001-11-19

    A new concept for the design and laccase-catalyzed preparation of "artificial urushi" from new urushiol analogues is described. The curing proceeded under mild reaction conditions to produce the very hard cross-linked film (artificial urushi) with a high gloss surface. A new cross-linkable polyphenol was synthesized by oxidative polymerization of cardanol, a phenol derivative from cashew-nut-shell liquid, by enzyme-related catalysts. The polyphenol was readily cured to produce the film (also artificial urushi) showing excellent dynamic viscoelasticity. PMID:11763444

  17. Effects of the Artificial Skin Thickness on the Subsurface Pressure Profiles of Flat, Curved, and Braille Surfaces

    CERN Document Server

    Cabibihan, John-John; Suresh, Shruthi

    2014-01-01

    The primary interface of contact between a robotic or prosthetic hand and the external world is through the artificial skin. To make sense of that contact, tactile sensors are needed. These sensors are normally embedded in soft, synthetic materials for protecting the subsurface sensor from damage or for better hand-to-object contact. It is important to understand how the mechanical signals transmit from the artificial skin to the embedded tactile sensors. In this paper, we made use of a finite element model of an artificial fingertip with viscoelastic and hyperelastic behaviors to investigate the subsurface pressure profiles when flat, curved, and Braille surfaces were indented on the surface of the model. Furthermore, we investigated the effects of 1, 3 and 5 mm thickness of the skin on the subsurface pressure profiles. The simulation results were experimentally validated using a 25.4 {\\mu}m thin pressure detecting film that was able to follow the contours of a non-planar surface, which is analogous to an ar...

  18. Fibular Allograft and Demineralized Bone Matrix for the Treatment of Slipped Capital Femoral Epiphysis.

    Science.gov (United States)

    Murray, Travis; Morscher, Melanie A; Krahe, Amy M; Adamczyk, Mark J; Weiner, Dennis S

    2016-05-01

    Previous studies documented the use of fibular allograft in the treatment of slipped capital femoral epiphysis (SCFE) with bone graft epiphysiodesis (BGE). This study describes the results of using a 10-mm diameter premilled fibular allograft packed with demineralized bone matrix placed across the physis in an open surgical approach under image intensification. A review identified 45 cases of BGE using fibular allograft and demineralized bone matrix in 34 patients with a diagnosis of SCFE performed by a single surgeon during an 8-year period. Thirty-four cases (25 patients) had at least 1 year of follow-up and were included in the study. Medical records were reviewed for complications, subsequent surgeries, and time to physeal closure. Of the 34 cases included, there were no cases of acute chondrolysis. Complications included 1 case of bone graft extrusion that required surgical replacement and 1 re-slip requiring surgical stabilization. Five cases of avascular necrosis (AVN) were encountered (1 unstable slip with total head AVN, and 4 stable slips with 3 total head and 1 partial head AVN). In 1 patient, small loose bony fragments were noted on postoperative radiographs that appeared outside of the articular surface of the hip and were asymptomatic. Two patients encountered wound healing issues that resolved with appropriate wound care. In light of the occurrence of AVN in stable cases, BGE with autogenous corticocancellous graft is preferable to BGE with autologous fibular graft for the treatment of SCFE. [Orthopedics. 2016; 39(3):e519-e525.].

  19. Antibacterial and osteoinductive properties of demineralized bone matrix treated with silver

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, S.J.; Spadaro, J.A.; Webster, D.A.

    The problems incurred by storage of demineralized bone allograft material and its potential use in contaminated operative sites make an antibacterial property desirable. Silver was considered for this role because of its wide spectrum of antibacterial susceptibility, low incidence of resistance, and its ability to persistently inhibit bacteria after binding to collagen matrices. Demineralized bone matrix prepared from rat diaphyseal bone segments was treated by exposure fo AgCl, AgNO3 and NaNO3 solutions prior to lyophilization. The resulting material was tested for bacterial inhibition after incubation in saline solutions for various times and showed inhibition persisting for at least four weeks (Ag-treated material only). Silver treating the matrix was found to partially inhibit the osteoinductive capacity at 10(-3) and 10(-2) M but not at 10(-5) M as measured by intramuscular implantation in the rat for six weeks. Control and NaNo3-treated specimens showed normal bone growth as measured by ashing and by 99mTc binding, and confirmed by radiologic densities. Histologic sections showed dense microdeposits on dense material predominately near the decalcified bone surfaces, but also within the matrix. The results suggest that pretreatment with silver at concentrations in the 10(-4) range would render the implant material antibacterial, protect its sterility, and leave the osteoinductive capacity intact.

  20. Artificial neural network approach for estimation of surface specific humidity and air temperature using Multifrequency Scanning Microwave Radiometer

    Indian Academy of Sciences (India)

    Randhir Singh; B G Vasudevan; P K Pal; P C Joshi

    2004-03-01

    Microwave sensor MSMR (Multifrequency Scanning Microwave Radiometer) data onboard Oceansat-1 was used for retrieval of monthly averages of near surface specific humidity (a) and air temperature (a) by means of Artificial Neural Network (ANN). The MSMR measures the microwave radiances in 8 channels at frequencies of 6.6, 10.7, 18 and 21 GHz for both vertical and horizontal polarizations. The artificial neural networks (ANN) technique is employed to find the transfer function relating the input MSMR observed brightness temperatures and output (a and a) parameters. Input data consist of nearly 28 months (June 1999 — September 2001) of monthly averages of MSMR observed brightness temperature and surface marine observations of a and a from Comprehensive Ocean- Atmosphere Data Set (COADS). The performance of the algorithm is assessed with independent surface marine observations. The results indicate that the combination of MSMR observed brightness temperatures as input parameters provides reasonable estimates of monthly averaged surface parameters. The global root mean square (rms) differences are 1.0°C and 1.1 g kg−1 for air temperature and surface specific humidity respectively.

  1. Analysis and occurrence of seven artificial sweeteners in German waste water and surface water and in soil aquifer treatment (SAT).

    Science.gov (United States)

    Scheurer, Marco; Brauch, Heinz-J; Lange, Frank T

    2009-07-01

    A method for the simultaneous determination of seven commonly used artificial sweeteners in water is presented. The analytes were extracted by solid phase extraction using Bakerbond SDB 1 cartridges at pH 3 and analyzed by liquid chromatography electrospray ionization tandem mass spectrometry in negative ionization mode. Ionization was enhanced by post-column addition of the alkaline modifier Tris(hydroxymethyl)amino methane. Except for aspartame and neohesperidin dihydrochalcone, recoveries were higher than 75% in potable water with comparable results for surface water. Matrix effects due to reduced extraction yields in undiluted waste water were negligible for aspartame and neotame but considerable for the other compounds. The widespread distribution of acesulfame, saccharin, cyclamate, and sucralose in the aquatic environment could be proven. Concentrations in two influents of German sewage treatment plants (STPs) were up to 190 microg/L for cyclamate, about 40 microg/L for acesulfame and saccharin, and less than 1 microg/L for sucralose. Removal in the STPs was limited for acesulfame and sucralose and >94% for saccharin and cyclamate. The persistence of some artificial sweeteners during soil aquifer treatment was demonstrated and confirmed their environmental relevance. The use of sucralose and acesulfame as tracers for anthropogenic contamination is conceivable. In German surface waters, acesulfame was the predominant artificial sweetener with concentrations exceeding 2 microg/L. Other sweeteners were detected up to several hundred nanograms per liter in the order saccharin approximately cyclamate > sucralose. PMID:19533103

  2. Physicomechanical properties of the extracellular matrix of a demineralized bone

    Science.gov (United States)

    Kirilova, I. A.; Sharkeev, Yu. P.; Nikolaev, S. V.; Podorozhnaya, V. T.; Uvarkin, P. V.; Ratushnyak, A. S.; Chebodaeva, V. V.

    2016-08-01

    The article describes the results of a study of physicomechanical properties of a demineralized bone matrix of human cancellous and compact bones. A demineralized cancellous bone was shown to have the best characteristics of a porous system for colonization of matrices by cells. The ultimate stress and elasticity modulus of samples of demineralized femoral heads isolated in primary hip replacement was demonstrated to vary in wide ranges. The elasticity modulus ranged from 50 to 250 MPa, and the tensile strength varied from 1.1 to 5.5 MPa. Microhardness measurements by the recovered indentation method were not possible because of the viscoelastic properties of a bone material. To study the piezoelectric properties of samples, a measuring system was developed that comprised a measuring chamber with contact electrodes, a system for controlled sample loading, an amplifier-converter unit, and signal recording and processing software. The measurement results were used to determine the dependence of the signal amplitude on the dynamic deformation characteristics. The findings are discussed in terms of the relationship between the mechanical and electrical properties and the structure of the organic bone component.

  3. Enamel and dentine demineralization by a combination of starch and sucrose in a biofilm – caries model

    Directory of Open Access Journals (Sweden)

    Juliana Nunes BOTELHO

    2016-01-01

    Full Text Available Abstract Sucrose is the most cariogenic dietary carbohydrate and starch is considered non-cariogenic for enamel and moderately cariogenic for dentine. However, the cariogenicity of the combination of starch and sucrose remains unclear. The aim of this study was to evaluate the effect of this combination on Streptococcus mutans biofilm composition and enamel and dentine demineralization. Biofilms of S. mutans UA159 were grown on saliva-coated enamel and dentine slabs in culture medium containing 10% saliva. They were exposed (8 times/day to one of the following treatments: 0.9% NaCl (negative control, 1% starch, 10% sucrose, or 1% starch and 10% sucrose (starch + sucrose. To simulate the effect of human salivary amylase on the starch metabolization, the biofilms were pretreated with saliva before each treatment and saliva was also added to the culture medium. Acidogenicity of the biofilm was estimated by evaluating (2 times/day the culture medium pH. After 4 (dentine or 5 (enamel days of growth, biofilms (n = 9 were individually collected, and the biomass, viable microorganism count, and polysaccharide content were quantified. Dentine and enamel demineralization was assessed by determining the percentage of surface hardness loss. Biofilms exposed to starch + sucrose were more acidogenic and caused higher demineralization (p < 0.0001 on either enamel or dentine than those exposed to each carbohydrate alone. The findings suggest that starch increases the cariogenic potential of sucrose.

  4. Evaluation of penetration depth of a commercially available resin infiltrate into artificially created enamel lesions: An in vitro study

    Directory of Open Access Journals (Sweden)

    Priya Subramaniam

    2014-01-01

    Full Text Available Background: Early enamel lesions have a potential to re-mineralize and prevent caries progress. Aim: The aim of the following study is to determine the depth of penetration of low viscosity resin into artificially created enamel lesions. Materials and Methods: A sample of 20 sound premolars, indicated for orthodontic extraction, formed the study group. The teeth were coated with a nail varnish, leaving a window of 4 mm × 4 mm, on buccal surfaces of sound, intact enamel. Each tooth was subsequently immersed in demineralizing solution for 4 days to produce artificial enamel lesions. The demineralized area was then infiltrated with low viscosity resin (Icon Infiltrant, DMG, Hamburg, Germany as per the manufacturer′s instructions. All the restored teeth were then immersed in methylene blue dye for 24 h at 37°C. Teeth were then sectioned longitudinally through the lesion into two halves. The sections were observed under stereomicroscope at ×80 magnification and depth of penetration of the material was measured quantitatively using Motic software. Results: The maximum depth of penetration of the resin material was 6.06 ± 3.31 μm. Conclusions: Resin infiltration technique appears to be effective in sealing enamel lesions and has great potential for arresting white spot lesions.

  5. Development of bacterial biofilms on artificial corals in comparison to surface-associated microbes of hard corals.

    Directory of Open Access Journals (Sweden)

    Michael John Sweet

    Full Text Available Numerous studies have demonstrated the differences in bacterial communities associated with corals versus those in their surrounding environment. However, these environmental samples often represent vastly different microbial micro-environments with few studies having looked at the settlement and growth of bacteria on surfaces similar to corals. As a result, it is difficult to determine which bacteria are associated specifically with coral tissue surfaces. In this study, early stages of passive settlement from the water column to artificial coral surfaces (formation of a biofilm were assessed. Changes in bacterial diversity (16S rRNA gene, were studied on artificially created resin nubbins that were modelled from the skeleton of the reef building coral Acropora muricata. These models were dip-coated in sterile agar, mounted in situ on the reef and followed over time to monitor bacterial community succession. The bacterial community forming the biofilms remained significantly different (R = 0.864 p<0.05 from that of the water column and from the surface mucus layer (SML of the coral at all times from 30 min to 96 h. The water column was dominated by members of the α-proteobacteria, the developed community on the biofilms dominated by γ-proteobacteria, whereas that within the SML was composed of a more diverse array of groups. Bacterial communities present within the SML do not appear to arise from passive settlement from the water column, but instead appear to have become established through a selection process. This selection process was shown to be dependent on some aspects of the physico-chemical structure of the settlement surface, since agar-coated slides showed distinct communities to coral-shaped surfaces. However, no significant differences were found between different surface coatings, including plain agar and agar enhanced with coral mucus exudates. Therefore future work should consider physico-chemical surface properties as

  6. Designing artificial two dimensional electron lattice on metal surface: a Kagome-like lattice as an example

    Science.gov (United States)

    Li, Shuai; Qiu, Wen-Xuan; Gao, Jin-Hua

    2016-06-01

    Recently, a new kind of artificial two dimensional (2D) electron lattice on the nanoscale, i.e. molecular graphene, has drawn a lot of interest, where the metal surface electrons are transformed into a honeycomb lattice via absorbing a molecular lattice on the metal surface [Gomes et al., Nature, 2012, 438, 306; Wang et al., Phys. Rev. Lett., 2014, 113, 196803]. In this work, we theoretically demonstrate that this technique can be readily used to build other complex 2D electron lattices on a metal surface, which are of high interest in the field of condensed matter physics. The main challenge to build a complex 2D electron lattice is that this is a quantum antidot system, where the absorbed molecule normally exerts a repulsive potential on the surface electrons. Thus, there is no straightforward corresponding relation between the molecular lattice pattern and the desired 2D lattice of surface electrons. Here, we give an interesting example about the Kagome lattice, which has exotic correlated electronic states. We design a special molecular pattern and show that this molecular lattice can transform the surface electrons into a Kagome-like lattice. The numerical simulation is conducted using a Cu(111) surface and CO molecules. We first estimate the effective parameters of the Cu/CO system by fitting experimental data of the molecular graphene. Then, we calculate the corresponding energy bands and LDOS of the surface electrons in the presence of the proposed molecular lattice. Finally, we interpret the numerical results by the tight binding model of the Kagome lattice. We hope that our work can stimulate further theoretical and experimental interest in this novel artificial 2D electron lattice system.

  7. The effect of argon laser irradiation on demineralization resistance of human enamel adjacent to orthodontic brackets: an in vitro study.

    Science.gov (United States)

    Noel, Lloyd; Rebellato, Joe; Sheats, Rose D

    2003-06-01

    Argon lasers, because of their significant timesavings over conventional curing lights, have been investigated for use in bonding orthodontic brackets. They are also being investigated for their ability to confer demineralization resistance on enamel, which is of great interest in orthodontics. A two-part in vitro study on 86 human posterior teeth was conducted to determine the effects of a five-second argon laser exposure on shear bond strength and to evaluate the effects of a five- and 10-second argon laser exposure (250 mW) on demineralization of enamel surrounding orthodontic brackets after exposure to an artificial caries bath. Brackets cured with the argon laser for five seconds yielded mean bond strengths similar to those attained with a 40-second conventional light-cured control (n = 13 per group, 20.4 vs 17.8 MPa). Brackets cured with the argon laser for 10 seconds resulted in significantly lower mean lesion depth when compared with a visible light control (n = 20 per group, 107.8 vs 137.2 microm, P = .038). There were no statistically significant differences in lesion depth between the five-second argon laser and the visible light control groups. Overall, there was a 15% and 22% reduction in lesion depths for the five- and 10-second group, respectively. Poor correlations were found between the clinical appearance of decalcifications and their lesion depth. Argon lasers used for bonding orthodontic brackets would save a significant amount of chair time while possibly conferring demineralization resistance upon the enamel. PMID:12828433

  8. Comparison of Regression and Artificial Neural Network Models for Surface Roughness Prediction with the Cutting Parameters in CNC Turning

    Directory of Open Access Journals (Sweden)

    Muammer Nalbant

    2007-06-01

    Full Text Available Surface roughness, an indicator of surface quality, is one of the most specified customer requirements in machining of parts. In this study, the experimental results corresponding to the effects of different insert nose radii of cutting tools (0.4, 0.8, 1.2 mm, various depth of cuts (0.75, 1.25, 1.75, 2.25, 2.75 mm, and different feedrates (100, 130, 160, 190, 220 mm/min on the surface quality of the AISI 1030 steel workpieces have been investigated using multiple regression analysis and artificial neural networks (ANN. Regression analysis and neural network-based models used for the prediction of surface roughness were compared for various cutting conditions in turning. The data set obtained from the measurements of surface roughness was employed to and tests the neural network model. The trained neural network models were used in predicting surface roughness for cutting conditions. A comparison of neural network models with regression model was carried out. Coefficient of determination was 0.98 in multiple regression model. The scaled conjugate gradient (SCG model with 9 neurons in hidden layer has produced absolute fraction of variance (R2 values of 0.999 for the training data, and 0.998 for the test data. Predictive neural network model showed better predictions than various regression models for surface roughness. However, both methods can be used for the prediction of surface roughness in turning.

  9. Quantification of four artificial sweeteners in Finnish surface waters with isotope-dilution mass spectrometry.

    Science.gov (United States)

    Perkola, Noora; Sainio, Pirjo

    2014-01-01

    The artificial sweeteners sucralose (SCL), acesulfame (ACS), saccharin (SAC), and cyclamate (CYC) have been detected in environmental waters in Europe and North America. Higher environmental levels are expected in view of the increasing consumption of these food additives. In this study, an isotope-dilution mass spectrometry (IDMS) LC-MS/MS method was developed and validated for quantifying the four artificial sweeteners in boreal lakes (n = 3) and rivers (n = 12). The highest concentrations of ACS, SAC, CYC and SCL were 9,600, 490, 210 and 1000 ng/L, respectively. ACS and SAC were detected in all studied samples, and CYC and SCL in 98% and 56% of the samples. Seasonal trends of ACS and SAC were observed in some rivers. ACS and SCL concentrations in rivers correlated linearly with population equivalents of the wastewater treatment plants in the catchment areas, whereas SAC and CYC concentrations depend more on the source. PMID:24100049

  10. Surface modification of cellulose materials : from wood pulps to artificial blood vessels

    OpenAIRE

    Ahrenstedt, Lage

    2007-01-01

    This thesis describes the improvement of two radically different cellulose materials, paper and artificial blood vessels, constructed from two diverse cellulose sources, wood pulp and Acetobacter xylinum. The improvement of both materials was possible due to the natural affinity of the hemicellulose xyloglucan for cellulose. Chemical and mechanical pulps were treated with xyloglucan in the wet-end prior to hand sheet formation or by spray application of dry hand sheets, loading a comparable a...

  11. An investigation into the maintenance of a third generation artificial rugby surface

    OpenAIRE

    Wellings, Greg

    2013-01-01

    The endorsement of artificial turf for rugby by the sport’s governing bodies has seen a proliferation in facilities from grass roots to professional level. Maintenance of these facilities has become an important factor for discussion within the sports turf industry with organisations emphasising the need for well resourced, regular maintenance so that product quality and longevity may be maximised. Current knowledge and research has largely focussed on materials behaviour and the interacti...

  12. Direct in vivo study of flowing blood-artificial surface interactions - an original application of dynamic isotopic techniques

    International Nuclear Information System (INIS)

    A Ge(Li) detector, associated with a data acquisition and storage unit, and a data analysis facility, was used to record sequentially the activity, related to several radioisotopes, inside an extracorporeal shunt, settled between the femoral artery and the colateral vein of an anaesthetized dog. The shunt was made of a material, the haemocompatibility of which needed to be evaluated. Before the blood was allowed to flow through the shunt, the circulation of the dog was fed with technetium- or indium-labelled biological species thought to be concerned with blood-artificial surface interactions. The method described here offers the possibility of computing kinetic parameters for these interactions. (author)

  13. Suppression of power-coal dust at an open stockpile of the Neryugrinsk surface mine using artificial snow

    Energy Technology Data Exchange (ETDEWEB)

    Uskov, V.I.; Safonov, M.V.; Kupin, A.N.; Kruglova, E.S.

    1986-01-01

    Discusses complex dust suppression scheme at the open coal stockpile of the Neryungrinsk surface mine (winter temperature -50 C and lower) based on application of artificial snow and removal of dusty air for subsequent purification. The system consists of eight ejectors mounted at the top of the discharge structure with diffusers inclined at 60-80 degrees. Water consumption through type GEhF-200 hydroejector and type FKEh sprinkler is equal to 30-50 l/min at 10-20 MPa. Description of the equipment and mode of operation is given. States that up to 60% efficiency in dust suppression can be achieved. 5 refs.

  14. Using an artificial neural network approach to estimate surface-layer optical turbulence at Mauna Loa, Hawaii.

    Science.gov (United States)

    Wang, Yao; Basu, Sukanta

    2016-05-15

    In this Letter, an artificial neural network (ANN) approach is proposed for the estimation of optical turbulence (Cn2) in the atmospheric surface layer. Five routinely available meteorological variables are used as the inputs. Observed Cn2 data near the Mauna Loa Observatory, Hawaii are utilized for validation. The proposed approach has demonstrated its prowess by capturing the temporal evolution of Cn2 remarkably well. More interestingly, this ANN approach is found to outperform a widely used similarity theory-based conventional formulation for all the prevalent atmospheric conditions (including strongly stratified conditions). PMID:27176996

  15. Artificial Neural Network and Response Surface Methodology Modeling in Ionic Conductivity Predictions of Phthaloylchitosan-Based Gel Polymer Electrolyte

    Directory of Open Access Journals (Sweden)

    Ahmad Danial Azzahari

    2016-01-01

    Full Text Available A gel polymer electrolyte system based on phthaloylchitosan was prepared. The effects of process variables, such as lithium iodide, caesium iodide, and 1-butyl-3-methylimidazolium iodide were investigated using a distance-based ternary mixture experimental design. A comparative approach was made between response surface methodology (RSM and artificial neural network (ANN to predict the ionic conductivity. The predictive capabilities of the two methodologies were compared in terms of coefficient of determination R2 based on the validation data set. It was shown that the developed ANN model had better predictive outcome as compared to the RSM model.

  16. Efficacy of various topical agents to prevent enamel demineralization

    Directory of Open Access Journals (Sweden)

    Priska Lestari Hendrawan

    2011-09-01

    Full Text Available Background: Enamel demineralization is a common and undesirable side effect of fixed appliance orthodontic treatment. Many sudies showed that the prevalence varied between 2–96%. There are many ways to prevent demineralization and increased remineralization such as oral hygiene instruction and by topical application such as acidulated phosphate fluor (APF casein phospo peptide-amorphous calcium phosphate (CPP-ACP, casein phospo peptide-amorphous calcium phosphate plus (CPP-ACPF. Purpose: The purpose of this in-vitro study was to evaluate the efficacy of various topical agents to prevent enamel demineralization. Methods: Fourty extracted human premolars were allocated to 1 of 4 groups: 1.23% APF gel; 10% CPP-ACP paste; 10% CPP-ACPF paste; and untreated control. All samples were subjected to pH cycling treatment for 12 days through a daily procedure of demineralization solution with pH 4 for 6 hours and remineralization solution with pH 7 for 18 hours. Microhardness testing were done before and after pH cycling and the delta hardness values were determined. Results: APF, CPP-ACP and CPP-ACPF application significantly prevent lowering of enamel microhardness value compared with untreated control group. Kruskal-Wallis, ANOVA, Mann-Whitney U, Tukey and Bonferroni Post-Hoc multiple comparison test showed significant difference between mean delta microhardness value of CPP-ACPF and CPP-ACP group with APF group, but there is no significant difference between mean delta microhardness value of CPP-ACPF and CPP-ACP group. Conclusion: APF, CPP-ACP and CPP-ACPF prevent enamel demineralization. CPP-ACP and CPP-ACPF prevent demineralization more than APF.Latar belakang: Demineralisasi email merupakan efek samping negatif yang sering dijumpai pada perawatan ortodontik cekat. Beberapa penelitian menyatakan bahwa prevalensinya bervariasi 2–96 persen. Ada beberapa cara untuk mencegah demineralisasi dan meningkatkan remineralisasi, misalnya dengan instruksi

  17. LiNbO3 coating on concrete surface: a new and environmentally friendly route for artificial photosynthesis.

    Science.gov (United States)

    Nath, Ranjit K; Zain, M F M; Kadhum, Abdul Amir H

    2013-01-01

    The addition of a photocatalyst to ordinary building materials such as concrete creates environmentally friendly materials by which air pollution or pollution of the surface can be diminished. The use of LiNbO3 photocatalyst in concrete material would be more beneficial since it can produce artificial photosynthesis in concrete. In these research photoassisted solid-gas phases reduction of carbon dioxide (artificial photosynthesis) was performed using a photocatalyst, LiNbO3, coated on concrete surface under illumination of UV-visible or sunlight and showed that LiNbO3 achieved high conversion of CO2 into products despite the low levels of band-gap light available. The high reaction efficiency of LiNbO3 is explained by its strong remnant polarization (70 µC/cm(2)), allowing a longer lifetime of photoinduced carriers as well as an alternative reaction pathway. Due to the ease of usage and good photocatalytic efficiency, the research work done showed its potential application in pollution prevention. PMID:24376384

  18. LiNbO3 Coating on Concrete Surface: A New and Environmentally Friendly Route for Artificial Photosynthesis

    Directory of Open Access Journals (Sweden)

    Ranjit K. Nath

    2013-01-01

    Full Text Available The addition of a photocatalyst to ordinary building materials such as concrete creates environmentally friendly materials by which air pollution or pollution of the surface can be diminished. The use of LiNbO3 photocatalyst in concrete material would be more beneficial since it can produce artificial photosynthesis in concrete. In these research photoassisted solid-gas phases reduction of carbon dioxide (artificial photosynthesis was performed using a photocatalyst, LiNbO3, coated on concrete surface under illumination of UV-visible or sunlight and showed that LiNbO3 achieved high conversion of CO2 into products despite the low levels of band-gap light available. The high reaction efficiency of LiNbO3 is explained by its strong remnant polarization (70 µC/cm2, allowing a longer lifetime of photoinduced carriers as well as an alternative reaction pathway. Due to the ease of usage and good photocatalytic efficiency, the research work done showed its potential application in pollution prevention.

  19. Accumulation of artificial radionuclides in agricultural plants in the area used for surface nuclear tests

    International Nuclear Information System (INIS)

    The paper reports on the study of artificial radionuclide accumulation in agricultural crops grown at the territory with high concentration of radionuclides, and first of all – with high concentration of transuranium elements. As a result of this work, peculiarities of accumulation and distribution of artificial radionuclides in the vegetative and generative organs of the studied plants have been revealed. Basic accumulation factors have been found for 137Cs, 90Sr, 239+240Pu, and 241Am in agricultural products. Accumulation factor dependence on type of planting was found for the investigated types of plants. It has been found that the vegetative organs accumulate radionuclides most of all. - Highlights: • The experiment with plants was performed under natural conditions in the area of ground nuclear explosions at “Experimental field” site of the Semipalatinsk test site. • Nature of radionuclides distribution in different plant organs has been revealed. • Main accumulation factors for 137Cs, 90Sr, 239+240Pu and 241Am have been obtained for the crop products. • Obtained results are of particular importance in the issues related to assessments of radiological environmental contamination and its consequences

  20. INHIBITION OF BOVINE DENTIN DEMINERALIZATION BY A GLUTARDIALDEHYDE PRETREATMENT - AN INVITRO CARIES STUDY

    NARCIS (Netherlands)

    DEVRIES, J; TENBOSCH, J; OGAARD, B; ARENDS, J

    1993-01-01

    Intact bovine dentin specimens were demineralized in 25 mmol acetic acid buffers (pH 5), with and without a 5-min pretreatment with an acidic 2% glutardialdehyde (GDA) solution. The results demonstrate that GDA inhibits dentin demineralization and that the inhibition depends strongly on the initial

  1. Proximal caries detection using digital subtraction radiography in the artificial caries activity model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Hoon; Lee, Gi Ja; Choi, Sam Jin; Park, Young Ho; Kim, Kyung Soo; Jin, Hyun Seok; Hong, Kyung Won; Oh, Berm Seok; Park, Hun Kuk [Department of Biomedical Engineering, School of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Choi, Yong Suk; Hwang, Eui Hwan [Department of Oral and Maxillofacial Radiology, Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

    2009-03-15

    The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Digital radiographs of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size no.2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. In artificial caries activity model, the range of lesional depth was 572-1,374 {mu}m and the range of lesional area was 36.95-138.52 mm{sup 2}. The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

  2. Compositional and crystallographic changes on enamel when irradiated by Nd:YAG or Er,Cr:YSGG lasers and its resistance to demineralization when associated with fluoride

    Science.gov (United States)

    Zezell, D. M.; Ana, P. A.; Benetti, C.; Goulart, V. P.; Bachmann, L.; Tabchoury, C. P. M.; Cury, J. A.

    2010-02-01

    This study investigated the compositional and crystallographic changes on enamel when irradiated by Er,Cr:YSGG (λ=2.7μm, 8.5J/cm2) or Nd:YAG (λ=1064nm, 84.9J/cm2 associated with black coating), its resistance to demineralization when irradiation is associated with fluoride (APF-gel), and CaF2-like material formation and retention. Sample surfaces were analyzed by ATR-FTIR (4000-650cm-1, 4cm-1) resolution. Irradiation with Er,Cr:YSGG laser promoted a significant decrease on carbonate content of enamel. After Nd:YAG irradiation, it was observed a significant decrease of carbonate and amides I and II. X-ray diffraction showed that both laser irradiations promoted formation of α-tricalcium phosphate and tetracalcium phosphate, and a significant increase on the crystal growth of the enamel apatite (ANOVA, pdetermined. The remaining slabs of each group were submitted to a 10-day pH-cycling model and, subsequently, enamel demineralization was evaluated by cross-sectional microhardness. Both lasers significantly reduced enamel demineralization (ANOVA, p<0.05), and the previous APF-gel application followed by laser showed the higher reduction of enamel demineralization. CaF2 formed before pH-cycling was significantly higher in groups were APF was associated with laser irradiation. After demineralization, these groups also presented higher CaF2 retention in respect to isolated treatments (only APF or only laser), suggesting its anticaries potential.

  3. Preparation and characterization of activated carbon from demineralized tyre char

    Science.gov (United States)

    Manocha, S.; Prasad, Guddu R.; Joshi, Parth.; Zala, Ranjitsingh S.; Gokhale, Siddharth S.; Manocha, L. M.

    2013-06-01

    Activated carbon is the most adsorbing material for industrial waste water treatment. For wider applications, the main consideration is to manufacture activated carbon from low cost precursors, which are easily available and cost effective. One such source is scrap tyres. Recently much effort has been devoted to the thermal degradation of tyres into gaseous and liquid hydrocarbons and solid char residue, all of which have the potential to be processed into valuable products. As for solid residue, char can be used either as low-grade reinforcing filler or as activated carbon. The product recovered by a typical pyrolysis of tyres are usually, 33-38 wt% pyrolytic char, 38-55 wt% oil and 10-30 wt% solid fractions. In the present work activated carbon was prepared from pyrolyzed tyre char (PC). Demineralization involves the dissolution of metal into acids i.e. HCl, HNO3 and H2SO4 and in base i.e. NaOH. Different concentration of acid and base were used. Sodium hydroxide showed maximum amount of metal oxide removal. Further the concentration of sodium hydroxide was varied from 1N to 6N. As the concentration of acid are increased demineralization increases. 6N Sodium hydroxide is found to be more effective demineralising agent of tyre char.

  4. Lactic acid demineralization of shrimp shell and chitosan synthesis

    Directory of Open Access Journals (Sweden)

    Alewo Opuada AMEH

    2015-05-01

    Full Text Available The use of lactic acid was compared to hydrochloric acid for shrimp shell demineralization in chitosan synthesis. Five different acid concentrations were considered for the study: 1.5M, 3.0M, 4.5M, 6.0M and 7.5M. After demineralization, the shrimp shell were deproteinized and subsequently deacetylated to produce chitosan using sodium hydroxide solution. The synthesized chitosan samples were characterized using solubility, FTIR, SEM, XRD and viscosity. The SEM, FTIR and XRD analysis indicated that chitosan was synthesized with a high degree of deacetylation (83.18±2.11 when lactic acid was used and 84.2±5.00 when HCl was used. The degree of deacetylation and the molecular weight of the chitosan samples were also estimated. ANOVA analysis (at 95% confidence interval indicated that acid type and concentration did not significantly affect the solubility, degree of deacetylation, viscosity and molecular weight of the chitosan within the range considered.

  5. Self-organization of 1-methylnaphthalene on the surface of artificial snow grains: a combined experimental-computational approach.

    Science.gov (United States)

    Heger, Dominik; Nachtigallová, Dana; Surman, František; Krausko, Ján; Magyarová, Beata; Brumovský, Miroslav; Rubeš, Miroslav; Gladich, Ivan; Klán, Petr

    2011-10-20

    A combined experimental-computational approach was used to study the self-organization and microenvironment of 1-methylnaphthalene (1MN) deposited on the surface of artificial snow grains from vapors at 238 K. The specific surface area of this snow (1.1 × 10(4) cm(2) g(-1)), produced by spraying very fine droplets of pure water from a nebulizer into liquid nitrogen, was determined using valerophenone photochemistry to estimate the surface coverage by 1MN. Fluorescence spectroscopy at 77 K, in combination with molecular dynamics simulations, and density functional theory (DFT) and second-order coupled cluster (CC2) calculations, provided evidence for the occurrence of ground- and excited-state complexes (excimers) and other associates of 1MN on the snow grains' surface. Only weak excimer fluorescence was observed for a loading of 5 × 10(-6) mol kg(-1), which is ∼2-3 orders of magnitude below monolayer coverage. However, the results indicate that the formation of excimers is favored at higher surface loadings (>5 × 10(-5) mol kg(-1)), albeit still being below monolayer coverage. The calculations of excited states of monomer and associated moieties suggested that a parallel-displaced arrangement is responsible for the excimer emission observed experimentally, although some other associations, such as T-shape dimer structures, which do not provide excimer emission, can still be relatively abundant at this surface concentration. The hydrophobic 1MN molecules, deposited on the ice surface, which is covered by a relatively flexible quasi-liquid layer at 238 K, are then assumed to be capable of dynamic motion resulting in the formation of energetically preferred associations to some extent. The environmental implications of organic compounds' deposition on snow grains and ice are discussed.

  6. Reversible Interactions of Proteins with Mixed Shell Polymeric Micelles: Tuning the Surface Hydrophobic/Hydrophilic Balance toward Efficient Artificial Chaperones.

    Science.gov (United States)

    Wang, Jianzu; Song, Yiqing; Sun, Pingchuan; An, Yingli; Zhang, Zhenkun; Shi, Linqi

    2016-03-22

    Molecular chaperones can elegantly fine-tune its hydrophobic/hydrophilic balance to assist a broad spectrum of nascent polypeptide chains to fold properly. Such precious property is difficult to be achieved by chaperone mimicking materials due to limited control of their surface characteristics that dictate interactions with unfolded protein intermediates. Mixed shell polymeric micelles (MSPMs), which consist of two kinds of dissimilar polymeric chains in the micellar shell, offer a convenient way to fine-tune surface properties of polymeric nanoparticles. In the current work, we have fabricated ca. 30 kinds of MSPMs with finely tunable hydrophilic/hydrophobic surface properties. We investigated the respective roles of thermosensitive and hydrophilic polymeric chains in the thermodenaturation protection of proteins down to the molecular structure. Although the three kinds of thermosensitive polymers investigated herein can form collapsed hydrophobic domains on the micellar surface, we found distinct capability to capture and release unfolded protein intermediates, due to their respective affinity for proteins. Meanwhile, in terms of the hydrophilic polymeric chains in the micellar shell, poly(ethylene glycol) (PEG) excels in assisting unfolded protein intermediates to refold properly via interacting with the refolding intermediates, resulting in enhanced chaperone efficiency. However, another hydrophilic polymer-poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) severely deteriorates the chaperone efficiency of MSPMs, due to its protein-resistant properties. Judicious combination of thermosensitive and hydrophilic chains in the micellar shell lead to MSPM-based artificial chaperones with optimal efficacy.

  7. Modeling and optimization of Newfoundland shrimp waste hydrolysis for microbial growth using response surface methodology and artificial neural networks.

    Science.gov (United States)

    Zhang, Kedong; Zhang, Baiyu; Chen, Bing; Jing, Liang; Zhu, Zhiwen; Kazemi, Khoshrooz

    2016-08-15

    The hydrolyzed protein derived from seafood waste is regarded as a premium and low-cost nitrogen source for microbial growth. In this study, optimization of enzymatic shrimp waste hydrolyzing process was investigated. The degree of hydrolysis (DH) with four processing variables including enzyme/substrate ratio (E/S), hydrolysis time, initial pH value and temperature, were monitored. The DH values were used for response surface methodology (RSM) optimization through central composite design (CCD) and for training artificial neural network (ANN) to make a process prediction. Results indicated that the optimum levels of variables are: E/S ratio at 1.64%, hydrolysis time at 3.59h, initial pH at 9 and temperature at 52.57°C. Hydrocarbon-degrading bacteria Bacillus subtilis N3-1P was cultivated using different DHs of hydrolysate. The associated growth curves were generated. The research output facilitated effective shrimp waste utilization. PMID:27312986

  8. A Method for Creating Artificial Thrombi In Vitro Using a Rotating Mechanical Surface.

    Science.gov (United States)

    Jessen, Staci L; Masse, Andrew M; Carpenter, Mallory D; Clubb, Fred J; Weeks, Brad R

    2016-01-01

    Thromboembolism is a common concern in ventricular assist device (VAD) therapy. Precise VAD response to pass-through thromboembolism needs to be studied in a controlled in vitro setting where specific pump parameters (i.e., power consumption, flow rates, impeller RPM) can be monitored while various types of thrombi are introduced. In this article, we describe a method for creating standardized fibrin thrombi that could be introduced into a mock circulatory loop for testing VAD response to thromboembolism. Donor equine blood collected using a sodium citrate was allowed to clot by adding calcium chloride (CaCl2) while a rotating component applied shear forces to the blood. This rotating force was applied at various speeds and at various distances into the blood. Resulting clots showed similar microscopic features to thrombi taken from explanted clinical VADs. Higher RPM of the rotating component and smaller clearances between the rotating component and the blood created clots that closely resembled ante-explant clots found within VADs in vivo. This method is an effective way to create artificial fibrin clots for use in in vitro experiments to test thromboembolism in VADs. PMID:26735557

  9. The effects of artificial surface temperature on mechanical properties and player kinematics during landing and acceleration

    Directory of Open Access Journals (Sweden)

    Laura Charalambous

    2016-09-01

    Conclusion: These findings highlight different demands placed on players due to the surface temperature and suggest a need for coaches, practitioners, and sports governing bodies to be aware of these differences.

  10. Map presentation of changes in Europe's artificial surfaces for the periods 1990-2000 and 2000-2006

    Science.gov (United States)

    Feranec, Jan; Soukup, Tomas

    2013-06-01

    The landscapes of the world are constantly changing under the influence of human activities leading to the growth of artificial surfaces. The covering of soil by artificial surfaces is referred to as soil sealing. Aerial and satellite images or data derived from them (for instance CORINE land cover — CLC data used here) provide important information that makes it possible to assess the occurrence, area and rate of soil sealing. As the term sealed soil cannot be wholly identified with the content of the appropriate CLC classes, the term land cover flow urbanization (LCFU) will be used here. The essence of this study is the demonstration and documentation of the trends of the LCFU in Europe for the periods 1990-2000 and 2000-2006 on a single map. This may contribute to a better spatial awareness of the ongoing transformation of landscape under the effects of human activities in an pan-European context. Changes in the LCFU can be seen on a map, compiled from 3 × 3 km squares at an all-European scale, using colours and their hues, to fulfil the role both of identification and classification. The colour method employed makes it possible to perceive three groups of LCFU changes on two time horizons, that is, whether the rate of LCFU in 2000-2006 increased or remained the same (hues of red); or dropped compared to the 1990-2000 period (hues of light to dark blue). The third group represents the LCFU with rates higher or lower than the average (countries with changes recorded in only one time horizon are presented in dark and light magenta colours).

  11. Unconventional Approach for Demineralization of Deproteinized Crustacean Shells for Chitin Production

    Directory of Open Access Journals (Sweden)

    N. S. Mahmoud

    2007-01-01

    Full Text Available Chitin is a versatile environmentally friendly modern material. It has a wide range of applications in areas such as water treatment, pulp and paper, biomedical devices and therapies, cosmetics, membrane technology and biotechnology and food applications. Crustacean waste is the most important chitin source for commercial use. Demineralization is an important step in the chitin purification process from crustacean waste. The conventional method of demineralization includes the use of strong acid (commonly HCl that harms the physiochemical properties of chitin, results in a harmful effluent wastewater and increases the cost of chitin purification process. The current study proposes the use of organic acids (lactic and acetic produced by cheese whey fermentation to demineralize microbially deproteinized shrimp shells. The effects of acid type, demineralization condition, retention time and shells to acid ratio were investigated. The study showed that the effectiveness of using lactic and/or acetic acids for demineralization of shrimp shells was comparable to that of using hydrochloric acid. Using organic acids for demineralization is a promising concept, since organic acids are less harmful to the environment, can preserve the characteristics of the purified chitin and can be produced from low cost biomass such as cheese whey. In addition, the resulted organic salts from the demineralization process can be used as a food preservative and/or an environmentally friendly de-icing/anti-icing agents.

  12. Effects of different surface treatments and accelerated artificial aging on the bond strength of composite resin repairs

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Veiga de Melo

    2011-12-01

    Full Text Available The purpose of the present study was to assess the bond strength of composite resin repairs subjected to different surface treatments and accelerated artificial aging. 192 cylindrical samples (CSs were prepared and divided into 24 groups (n = 8. Half of the CSs were stored in water for 24 h, and the other half were subjected to C-UV accelerated aging for non-metallic specimens. The treatments were phosphoric acid + silane + adhesive (PSA; phosphoric acid + adhesive (PA; diamond bur + phosphoric acid + silane + adhesive (DPSA; diamond bur + phosphoric acid + adhesive (DPA; air abrasion + phosphoric acid + silane + adhesive (APSA; and air abrasion + phosphoric acid + adhesive (APA. The repair was performed and the specimens were again aged as described above. A control group (n = 8 was established and did not receive any type of aging or surface treatment. The specimens were loaded to failure in shear mode with a crosshead speed of 0.5 mm/min until fracture. Data were analyzed by one-way ANOVA/Tukey's test (p < 0.05. No statistically significant differences were found among DPSA, DPA, APSA, APA, and the control group. The aged PSA and PA achieved low bonding values and were statistically different from the control group, whereas the non-aged PSA and PA presented no statistically significant difference from the control group. Repairs with the proposed surface treatments were viable on both recent and aged restorations; however, phosphoric acid + adhesive alone were effective only on recent restorations.

  13. APPLICATION OF HIERARCHY ARTIFICIAL NEURAL NETWORK TO EVALUATE THE EXPLOITATION CONDITITONS OF SURFACE MINING AREA

    Institute of Scientific and Technical Information of China (English)

    李新春; 范力军

    1998-01-01

    It always adopts the direct hierarchy analysis to value the exploitation conditions of surface mining areas. This way has some unavoidable shortcomings because it is mainly under theaid of experts and it is affected by the subjective thinking of the experts. This paper puts forwards a new approach that divides the whole exploitation conditions into sixteen subsidiary systems and each subsidiary system forms a neural network system. The whole decision system of exploitation conditions of surface mining areas is composed of sixteen subsidiary neural network systems. Each neural network is practiced with the data of the worksite, which is reasonable and scientific. This way will be a new decision approach for exploiting the surface mining areas.

  14. Near-infrared imaging of demineralization under sealants

    Science.gov (United States)

    Tom, Henry; Simon, Jacob C.; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel

    2014-07-01

    Previous studies have shown that near-infrared (NIR) reflectance and transillumination imaging can be used to acquire high contrast images of early caries lesions and composite restorative materials. The aim of the study was to determine the optimum NIR wavelengths for imaging demineralized areas under dental sealants. Fifteen natural human premolars and molars with occlusal lesions were used in this in vitro study. Images before and after application of sealants were acquired using NIR reflectance and NIR transillumination at wavelengths of 1300, 1460, and 1500 to 1700 nm. Images were also acquired using polarization sensitive optical coherence tomography (OCT) for comparison. The highest contrast for NIR reflectance was at 1460 nm and 1500 to 1700 nm. These NIR wavelengths are coincident with higher water absorption. The clear Delton sealant investigated was not visible in either copolarization or cross-polarization OCT images. The wavelength region between 1500 and 1700 nm yielded the highest contrast of lesions under sealants for NIR reflectance measurements.

  15. Evidence for Interactions between Surface Water and Periphyton Biofilms in Artificial Streams

    Science.gov (United States)

    Studies suggest that periphyton in streambeds can harbor fecal indicator bacteria (FIB) and, under certain circumstances, can be transferred from the periphyton biofilm into the surface water. An indoor mesocosm study was conducted at the U.S. Environmental Protection Agency Expe...

  16. Kinetic modelling of the demineralization of shrimp exoskeleton using citric acid

    OpenAIRE

    Alewo Opuada AMEH; Muhammed Tijani ISA; David ABUTU; Alibaba DANLAMI

    2014-01-01

    Citric acid was used in the demineralization of shrimp exoskeleton and the kinetics of the demineralization process was studied. Kinetic data was obtained by demineralisation using five acid concentrations (0.1, 0.2, 0.3, 0.4 and 0.5M). The obtained kinetic data were fitted to the shrinking core model for fluid particle reactions. The concentration of calcium was found to decrease with time. For all acid concentrations considered, the best predictive mechanism for the demineralization process...

  17. Ethylene oxide gas sterilization does not reduce the osteoinductive potential of demineralized bone in rats

    DEFF Research Database (Denmark)

    Solheim, E; Pinholt, E M; Bang, G;

    1995-01-01

    It has been shown that different sterilization procedures of demineralized bone may influence its osteoinductive properties. The aim of this study was to evaluate the effect of ethylene oxide sterilization for 1, 3, and 6 hours on the osteoinductive potential of allogeneic demineralized bone...... without prior sterilization of the material, whereas the demineralized bone implanted in Groups B, C, and D had been sterilized in ethylene oxide gas for 1, 3, or 6 hours, respectively, and aerated for 48 hours. At 4 weeks postoperatively, bone formation was evaluated quantitatively by strontium 85 uptake...

  18. MODELLING OF SURFACE OZONE USING ARTIFICIAL NEURAL NETWORK IN AN URBAN AREA

    Directory of Open Access Journals (Sweden)

    S.Stephen Rajkumar Inbanathan,

    2011-02-01

    Full Text Available In this paper a novel approach, based on a neural network structure, is introduced in order to face with the problem of pollutant estimation in an urban area. A neural architecture, based essentiallyon suitable number of layers devoted to predict alarm situations and to estimate the value of the pollutant, has been implemented. A new method for short term prediction is presented using the neural network technique. Due to increase in industrial and anthropogenic activity, air pollution is a serious subject of concern today. Surface ozone prediction using the technique of adaptive pattern recognition is developed. The model can predict the mean surface ozone based on the parameters like Nitrogen-dioxide, temperature and % Relative Humidity, wind direction, wind speed. The model can perform well both in training and independent periods. The classical methods of short term modeling are not reliable enough. The method can also be used for short term prediction of other air pollutants.

  19. Hybrid intelligence systems and artificial neural network (ANN) approach for modeling of surface roughness in drilling

    OpenAIRE

    Ch. Sanjay; Ch. Prithvi

    2014-01-01

    In machining processes, drilling operation is material removal process that has been widely used in manufacturing since industrial revolution. The useful life of cutting tool and its operating conditions largely controls the economics of machining operations. Drilling is most frequently performed material removing process and is used as a preliminary step for many operations, such as reaming, tapping, and boring. Drill wear has a bad effect on the surface finish and dimensional accuracy of th...

  20. New model of Mars surface irradiation for the climate simulation chamber 'Artificial Mars'

    Science.gov (United States)

    Tarasashvili, M. V.; Sabashvili, Sh. A.; Tsereteli, S. L.; Aleksidze, N. G.

    2013-04-01

    A new model of the Mars surface irradiation has been developed for the imitation of radiation-temperature parameters within Mars Climate Simulation Chamber (MCSC). In order to determine the values of annual and diurnal variations of the irradiance on the Martian surface, the Solar illumination E has been expressed by the distance r between the Sun and Mars and the Sun's altitude z in the Martian sky, along with its midday zenith distance z min. The arrangements of spring and autumn equinoxes as well as summer and winter solstice points in the Martian sky are discussed regarding the perihelion of Mars. Annual orbital points and variability of Solar z min for different planetary latitudes have been calculated for the 15 selected values of Mars's true anomaly, along with the illumination E for 12 hourly moments of Martian daytime on the Martian equator. These original calculations and the data which have been obtained are used for the construction of technical tools imitating variations of the surface irradiation and temperature within MCSC, programming of the supporting computer and the electric scheme, which provide proper remote control and set the environmental parameters that are analogues to the 24 hours 39 minutes circadian cycle on planet Mars. Spectral distribution as monochromatic irradiance, humidity control, atmospheric composition and other environmental parameters of planet Mars are also imitated and remotely controlled within MCSC, however, are not discussed in this particular article.

  1. Observation of the Degradation Characteristics and Scale of Unevenness on Three-dimensional Artificial Rock Joint Surfaces Subjected to Shear

    Science.gov (United States)

    Hong, Eun-Soo; Kwon, Tae-Hyuk; Song, Ki-Il; Cho, Gye-Chun

    2016-01-01

    The present study explores the degradation characteristics and scale of unevenness (small-scale roughness) on sheared rock joint surfaces at a low-stress regime. While the degradation characteristics of unevenness and the normal stress are mutually interrelated, an understanding of the degradation patterns of the three-dimensional roughness of rock joints is one of the important components needed to identify asperity failure characteristics and to quantify the role of damaged unevenness in establishing a shear strength model. A series of direct shear tests was performed on three-dimensional artificial rock joint surfaces at different normal stress levels. After shearing, the spatial distributions and statistical parameters of degraded roughness were analysed for the different normal stress levels. The length and area of the degraded zones showed bell-shaped distributions in a logarithmic scale, and the dominant scale (or the most frequently occurring scale) of the damaged asperities (i.e., unevenness) ranged from approximately, 0.5 to 5.0 mm in length and 0.1-10 mm2 in area. This scale of the damaged unevenness was consistent regardless of the level of normal stress. It was also found that the relative area of damaged unevenness on a given joint area, and thus the contribution of the mechanical asperity failure component to shear strength increased as normal stress increased.

  2. The effect of fluoride toothpaste on root dentine demineralization progression: a pilot study

    OpenAIRE

    Juliana Nunes Botelho; Altair Antoninha Del Bel Cury; Wander José da Silva; Livia Maria Andaló Tenuta; Jaime Aparecido Cury

    2014-01-01

    The anticaries effect of fluoride (F) toothpaste containing 1100 µg F/g in reducing enamel demineralization is well established, but its effect on dentine has not been extensively studied. Furthermore, it has been shown that toothpaste containing a high F concentration is necessary to remineralize root dentine lesions, suggesting that a 1100 µg F/g concentration might not be high enough to reduce root dentine demineralization, particularly when dentine is subjected to a high cariogenic challe...

  3. Minimal invasive surgery for unicameral bone cyst using demineralized bone matrix: a case series

    OpenAIRE

    Cho Hwan; Seo Sung; Park So; Park Jong; Shin Duk; Park Il

    2012-01-01

    Abstract Background Various treatments for unicameral bone cyst have been proposed. Recent concern focuses on the effectiveness of closed methods. This study evaluated the effectiveness of demineralized bone matrix as a graft material after intramedullary decompression for the treatment of unicameral bone cysts. Methods Between October 2008 and June 2010, twenty-five patients with a unicameral bone cyst were treated with intramedullary decompression followed by grafting of demineralized bone ...

  4. Growth Characteristics Modeling of Mixed Culture of Bifidobacterium bifidum and Lactobacillus acidophilus using Response Surface Methodology and Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Ganga Sahay Meena

    2014-12-01

    Full Text Available Different culture conditions viz. additional carbon and nitrogen content, inoculum size and age, temperature and pH of the mixed culture of Bifidobacterium bifidum and Lactobacillus acidophilus were optimized using response surface methodology (RSM and artificial neural network (ANN. Kinetic growth models were fitted for the cultivations using a Fractional Factorial (FF design experiments for different variables. This novel concept of combining the optimization and modeling presented different optimal conditions for the mixture of B. bifidum and L. acidophilus growth from their one variable at-a-time (OVAT optimization study. Through these statistical tools, the product yield (cell mass of the mixture of B. bifidum and L. acidophilus was increased. Regression coefficients (R2 of both the statistical tools predicted that ANN was better than RSM and the regression equation was solved with the help of genetic algorithms (GA. The normalized percentage mean squared error obtained from the ANN and RSM models were 0.08 and 0.3%, respectively. The optimum conditions for the maximum biomass yield were at temperature 38°C, pH 6.5, inoculum volume 1.60 mL, inoculum age 30 h, carbon content 42.31% (w/v, and nitrogen content 14.20% (w/v. The results demonstrated a higher prediction accuracy of ANN compared to RSM.

  5. In Vitro Cytotoxicity Test and Surface Characterization of CoCrW Alloy in Artificial Saliva Solution for Dental Applications.

    Science.gov (United States)

    Souza, Klester Santos; Jaimes, Ruth Flavia Vera Villamil; Rogero, Sizue Otta; Nascente, Pedro Augusto de Paula; Agostinho, Silvia Maria Leite

    2016-04-01

    In order to evaluate its application as a dental prosthesis material, a CoCrW alloy was subjected to in vitro cytotoxicity test, surface characterization and electrochemical studies performed in artificial saliva and 0.15 mol.L-1 NaCl medium. The used techniques were: anodic polarization curves, chronoamperometric measurements, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) analysis and X-ray photoelectron spectroscopy (XPS). Cytotoxicity test was also performed. The electrochemical behavior of CoCrW alloy was compared in both studied media, from corrosion potential (Ecorr) to a 600 mV anodic overvoltage. From the electrochemical measurements it was observed that the CoCrW alloy in both media presents only generalized corrosion. SEM and EDS analysis showed that the alloy presents carbide niobium and silicon and manganese oxides as nonmetallic inclusions. XPS results indicated that cobalt does not significantly contribute to the passivating film formation. Cytotoxicity test showed no cytotoxic character of CoCrW alloy. These results suggest that the CoCrW alloy can be used as biomaterial to be applied as prosthesis in dental implants. PMID:27058381

  6. Optimization of controlled release nanoparticle formulation of verapamil hydrochloride using artificial neural networks with genetic algorithm and response surface methodology.

    Science.gov (United States)

    Li, Yongqiang; Abbaspour, Mohammadreza R; Grootendorst, Paul V; Rauth, Andrew M; Wu, Xiao Yu

    2015-08-01

    This study was performed to optimize the formulation of polymer-lipid hybrid nanoparticles (PLN) for the delivery of an ionic water-soluble drug, verapamil hydrochloride (VRP) and to investigate the roles of formulation factors. Modeling and optimization were conducted based on a spherical central composite design. Three formulation factors, i.e., weight ratio of drug to lipid (X1), and concentrations of Tween 80 (X2) and Pluronic F68 (X3), were chosen as independent variables. Drug loading efficiency (Y1) and mean particle size (Y2) of PLN were selected as dependent variables. The predictive performance of artificial neural networks (ANN) and the response surface methodology (RSM) were compared. As ANN was found to exhibit better recognition and generalization capability over RSM, multi-objective optimization of PLN was then conducted based upon the validated ANN models and continuous genetic algorithms (GA). The optimal PLN possess a high drug loading efficiency (92.4%, w/w) and a small mean particle size (∼100nm). The predicted response variables matched well with the observed results. The three formulation factors exhibited different effects on the properties of PLN. ANN in coordination with continuous GA represent an effective and efficient approach to optimize the PLN formulation of VRP with desired properties. PMID:25986587

  7. Influence of finishing/polishing on color stability and surface roughness of composites submitted to accelerated artificial aging

    Directory of Open Access Journals (Sweden)

    Gustavo Da Col dos Santos Pinto

    2013-01-01

    Full Text Available Aim: To assess the influence of finishing/polishing procedure on color stability (ΔE and surface roughness (Ra of composites (Heliomolar and Tetric - color A2 submitted to accelerated artificial aging (AAA. Materials and Methods : Sixty test specimens were made of each composite (12 mm × 2 mm and separated into six groups (n = 10, according to the type of finishing/polishing to which they were submitted: C, control; F, tip 3195 F; FF, tip 3195 FF; FP, tip 3195 F + diamond paste; FFP, tip 3195 FF + diamond paste; SF, Sof-Lex discs. After polishing, controlled by an electromechanical system, initial color (spectrophotometer PCB 6807 BYK GARDNER and Ra (roughness meter Surfcorder SE 1700, cut-off 0.25 mm readings were taken. Next, the test specimens were submitted to the AAA procedure (C-UV Comexim for 384 hours, and at the end of this period, new color readings and R a were taken. Results: Statistical analysis [2-way analysis of variance (ANOVA, Bonferroni, P < 0.05] showed that all composites demonstrated ΔE alteration above the clinically acceptable limits, with the exception of Heliomolar composite in FP. The greatest ΔE alteration occurred for Tetric composite in SF (13.38 ± 2.10 statistically different from F and FF (P < 0.05. For Ra , Group F showed rougher samples than FF with statistically significant difference (P < 0.05. Conclusion: In spite of the surface differences, the different finishing/polishing procedures were not capable of providing color stability within the clinically acceptable limits.

  8. Predicting the impact of vegetations in open channels with different distributaries' operations on water surface profile using artificial neural networks

    International Nuclear Information System (INIS)

    Most of the open water irrigation channels in Egypt suffer from the infestation of aquatic weeds, especially the submerged ones that cause numerous hydraulic problems for the open channels themselves and their water distributaries such as increasing water losses, obstructing water flow, and reducing channels' water distribution efficiencies. Accurate simulation and prediction of flow behavior in such channels is very essential for water distribution decision makers. Artificial neural networks (ANN) have proven to be very successful in the simulation of several physical phenomena, in general, and in the water research field in particular. Therefore, the current study aims towards introducing the utilization of ANN in simulating the impact of vegetation in main open channel, which supplies water to different distributaries, on the water surface profile in this main channel. Specifically, the study, presented in the current paper utilizes ANN technique for the development of various models to simulate the impact of different submerged weeds' densities, different flow discharges, and different distributaries operation scheduling on the water surface profile in an experimental main open channel that supplies water to different distributaries. In the investigated experiment, the submerged weeds were simulated as branched flexible elements. The investigated experiment was considered as an example for implementing the same methodology and technique in a real open channel system. The results showed that the ANN technique is very successful in simulating the flow behavior of the pre-mentioned open channel experiment with the existence of the submerged weeds. In addition, the developed ANN models were capable of predicting the open channel flow behavior in all the submerged weeds' cases that were considered in the ANN development process

  9. Near-IR imaging of demineralization under sealants

    Science.gov (United States)

    Tom, Henry; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel

    2014-02-01

    Previous studies have shown that near-IR reflectance and transillumination imaging can be used to acquire high contrast images of early caries lesions and composite restorative materials. The aim of the study was to determine the optimum near-IR wavelengths for imaging demineralized areas under dental sealants. Fifteen natural human premolars and molars with occlusal lesions were used in this in vitro study. Images before and after application of sealants were acquired using near-IR reflectance and near-IR transillumination at wavelengths of 1300 nm, 1460 nm, and 1500 - 1700 nm. Images were also acquired using polarization sensitive optical coherence tomography for comparison. The highest contrast for near- IR reflectance was at 1460 nm and 1500 - 1700 nm. These near-IR wavelengths are coincident with higher water absorption. The clear Delton sealant investigated was not visible in either co-polarization or crosspolarization OCT images. The wavelength region between 1500-1700-nm yielded the highest contrast of lesions under sealants for near-IR reflectance measurements.

  10. Biomimetically Enhanced Demineralized Bone Matrix for Bone Regenerative Applications

    Directory of Open Access Journals (Sweden)

    Sriram eRavindran

    2015-10-01

    Full Text Available Demineralized bone matrix (DBM is one of the most widely used bone graft materials in dentistry. However, the ability of DBM to reliably and predictably induce bone regeneration has always been a cause for concern. The quality of DBM varies greatly depending on several donor dependent factors and also manufacturing techniques. In order to standardize the quality and to enable reliable and predictable bone regeneration, we have generated a biomimetically-enhanced version of DBM (BE-DBM using clinical grade commercial DBM as a control. We have generated the BE-DBM by incorporating a cell-derived pro-osteogenic extracellular matrix (ECM within clinical grade DBM. In the present study, we have characterized the BE-DBM and evaluated its ability to induce osteogenic differentiation of human marrow derived stromal cells (HMSCs with respect to clinical grade commercial DBM. Our results indicate that the BE-DBM contains significantly more pro-osteogenic factors than DBM and enhances HMSC differentiation and mineralized matrix formation in vitro and in vivo. Based on our results, we envision that the BE-DBM has the potential to replace DBM as the bone graft material of choice.

  11. Submerged demineralize system processing of TMI-2 accident waste water

    International Nuclear Information System (INIS)

    Accident-generated radioactive waste at Three Mile Island Unit 2 includes a varity of high and low specific-activity waste. The high-specific-activity waste, particularly over one million gallons of contaminated water, required special processing and secondary waste handling. General public utilities and its contractors developed a zeolite-based ion-exchange system called the Submerged Demineralizer System to reduce contamination levels in the water to below allowable limits. Testing and modifications resulted in an operating system that had successfully processed waste water from the Reactor Coolant Bleed Tanks, the Reactor Building Basement, and the Reactor Coolant System as of August 1982. System design objectives were met and decontamination criteria established in 10 CFR 20 were attained. Additional wastes that could not be handled routinely were generated by another water-processing system, called EPICOR II. EPICOR II wastes are discussed. Low-specific-activity (LSA) wastes such as trash and resin-bed waste canisters are also included in handling. LSA wastes are routinely handled and shipped according to existing industry practice. Plant records are summarized to provide approximate yearly volumes and curie loadings of low-specific-activity wastes being shipped off the Island to a commercial burial site

  12. Estimation of design space for an extrusion-spheronization process using response surface methodology and artificial neural network modelling.

    Science.gov (United States)

    Sovány, Tamás; Tislér, Zsófia; Kristó, Katalin; Kelemen, András; Regdon, Géza

    2016-09-01

    The application of the Quality by Design principles is one of the key issues of the recent pharmaceutical developments. In the past decade a lot of knowledge was collected about the practical realization of the concept, but there are still a lot of unanswered questions. The key requirement of the concept is the mathematical description of the effect of the critical factors and their interactions on the critical quality attributes (CQAs) of the product. The process design space (PDS) is usually determined by the use of design of experiment (DoE) based response surface methodologies (RSM), but inaccuracies in the applied polynomial models often resulted in the over/underestimation of the real trends and changes making the calculations uncertain, especially in the edge regions of the PDS. The completion of RSM with artificial neural network (ANN) based models is therefore a commonly used method to reduce the uncertainties. Nevertheless, since the different researches are focusing on the use of a given DoE, there is lack of comparative studies on different experimental layouts. Therefore, the aim of present study was to investigate the effect of the different DoE layouts (2 level full factorial, Central Composite, Box-Behnken, 3 level fractional and 3 level full factorial design) on the model predictability and to compare model sensitivities according to the organization of the experimental data set. It was revealed that the size of the design space could differ more than 40% calculated with different polynomial models, which was associated with a considerable shift in its position when higher level layouts were applied. The shift was more considerable when the calculation was based on RSM. The model predictability was also better with ANN based models. Nevertheless, both modelling methods exhibit considerable sensitivity to the organization of the experimental data set, and the use of design layouts is recommended, where the extreme values factors are more represented

  13. Artificial intelligence

    CERN Document Server

    Hunt, Earl B

    1975-01-01

    Artificial Intelligence provides information pertinent to the fundamental aspects of artificial intelligence. This book presents the basic mathematical and computational approaches to problems in the artificial intelligence field.Organized into four parts encompassing 16 chapters, this book begins with an overview of the various fields of artificial intelligence. This text then attempts to connect artificial intelligence problems to some of the notions of computability and abstract computing devices. Other chapters consider the general notion of computability, with focus on the interaction bet

  14. In vitro study of demineralization resistance and fluoride retention in dental enamel irradiated with Er,Cr: YSGG laser

    International Nuclear Information System (INIS)

    This study aimed to establish irradiation conditions of Er,Cr:YSGG laser (λ of 2.79 μm) which could propitiate changes on human dental enamel and increase its resistance to demineralization, when associated or not with topical application of acidulated phosphate fluoride (APF). Fluences of 2,8 J/cm2, 5,6 J/cm2 e 8,5 J/cm2 were selected; they were associated or not with previous application of a photo absorber (coal paste) and then APF was applied or not after laser irradiation. In a first step, the morphological findings, the surface temperatures, and the pupal temperatures were evaluated during laser irradiation. After that, the treated samples were submitted to a a ten-day pH-cycling model. After producing the incipient white-spots lesions, the following aspects were evaluated: the mineral loss, the loosely bound fluoride and the firmly bound fluoride. All the demineralizing and remineralizing pH-cycling solutions were evaluated with respect to their calcium (Ca), inorganic phosphorous (Pi) and fluoride (F-) concentrations. The data had their normality and homogeneity distribution statistically evaluated, and it was chosen an appropriated statistical test for each performed analysis according to the obtained results, considering 5% significant level. The fluences selected for this study created ablated surfaces; the fluences of 5.6 J/cm2 and 8.5 J/cm2 promoted increments in surface temperature above 110 deg C. The intrapupal temperature changes revealed that laser irradiation did not increase the pulpal temperatures above the critical threshold for induction of pulpitis. The coal paste did not promote any changes on surface morphology or in the intrapulpal temperature changes; however, this paste increased the surface temperatures during laser irradiation. Only laser irradiation at 8.5 J/cm2 was able to decrease the mineral loss when compared to the no-treatment group; although the association of coal paste + laser at 2.8 J/cm2 + APF application presented the

  15. Variability of soil enzyme activities and vegetation succession following boreal forest surface soil transfer to an artificial hill

    Directory of Open Access Journals (Sweden)

    Maarit Niemi

    2014-08-01

    Full Text Available A landfill site in southern Finland was converted into urban green space by covering it with a layer of fresh forest humus transferred from nearby construction sites. The aim was to develop the 70 m high artificial hill into a recreational area with high biodiversity of flora and fauna. Forest humus was used as a source of organic matter, plant roots, seeds, soil fauna and microorganisms in order to enable rapid regeneration of diverse vegetation and soil biological functions. In this study we report the results of three years of monitoring of soil enzyme activity and plant species compositional patterns. Monthly soil samples were taken each year between June and September from four sites on the hill and from two standing reference forests using three replicate plots. Activities of 10 different enzymes, soil organic matter (SOM content, moisture, pH and temperature of the surface layer were monitored. Abundances of vascular plant species were surveyed on the same four hill sites between late May and early September, three times a season in 2004 and 2005. Although the addition of organic soil considerably increased soil enzyme activities (per dw, the activities at the covered hill sites were far lower than in the reference forests. Temporal changes and differences between sites were analysed in more detail per soil organic matter (SOM in order to reveal differences in the quality of SOM. All the sites had a characteristic enzyme activity pattern and two hill sites showed clear temporal changes. The enzyme activities in uncovered topsoil increased, whereas the activities at the covered Middle site decreased, when compared with other sites at the same time. The different trend between Middle and North sites in enzyme activities may reflect differences in humus material transferred to these sites, but difference in the succession of vegetation affects enzyme activities strongly. Middle yielded higher β-sitosterol content in 2004, as an indication

  16. Kinetic modelling of the demineralization of shrimp exoskeleton using citric acid

    Directory of Open Access Journals (Sweden)

    Alewo Opuada AMEH

    2014-11-01

    Full Text Available Citric acid was used in the demineralization of shrimp exoskeleton and the kinetics of the demineralization process was studied. Kinetic data was obtained by demineralisation using five acid concentrations (0.1, 0.2, 0.3, 0.4 and 0.5M. The obtained kinetic data were fitted to the shrinking core model for fluid particle reactions. The concentration of calcium was found to decrease with time. For all acid concentrations considered, the best predictive mechanism for the demineralization process was determined to be Ash Layer Diffusion Control Mechanism. This was indicated by the high R2 values obtained (0.965 with 150% excess of citric acid.

  17. Demineralization of wood using wood-derived acid: Towards a selective pyrolysis process for fuel and chemicals production

    NARCIS (Netherlands)

    Oudenhoven, S.R.G; Westerhof, R.J.M.; Aldenkamp, N.; Brilman, D.W.F.; Kersten, S.R.A.

    2013-01-01

    A process concept for the pyrolysis of demineralized wood to obtain high organic and especially levoglucosan yields is proposed and tested experimentally. The wood is demineralized using organic acids, produced and concentrated within the same pyrolysis process. Pine wood was pyrolyzed in a fluidiz

  18. Demineralization of Sargassum spp. macroalgae biomass: selective hydrothermal liquefaction process for bio-oil production

    Directory of Open Access Journals (Sweden)

    Liz M Díaz-Vázquez

    2015-02-01

    Full Text Available Algae biomasses are considered a viable option for the production of biofuel because of their high yields of oil produced per dry weight. Brown macroalgae Sargassum spp. are one of the most abundant species of algae in the shores of Puerto Rico. Its availability in large quantity presents a great opportunity for use as a source of renewable energy. However, high ash content of macroalgae affects the conversion processes and the quality of resulting fuel products. This research studied the effect of different demineralization treatments of Sargassum spp. biomass, subsequent hydrothermal liquefaction (HTL and bio-oil characterization. Demineralization constituted five different treatments: nanopure water, nitric acid, citric acid, sulfuric acid, and acetic acid. Performance of demineralization was evaluated by analyzing both demineralized biomass and HTL products by the following analyses: total carbohydrates, proteins, lipids, ash content, caloric content, metals analysis, Fourier Transform Infrared - Attenuated Total Reflectance (FTIR-ATR Spectroscopy, Energy Dispersive Spectroscopy (EDS, Scanning Electron Microscopy (SEM, and GCMS analysis. HTL of Sargassum spp. before and after citric acid treatment, was performed in a 1.8 L batch reactor system at 350°C with a holding time of 60 min and high pressures (5-21 MPa. Demineralization treatment with nitric acid was found the most effective in reducing the ash content of the macroalgae biomass from 27.46% to 0.99% followed by citric acid treatment that could reduce the ash content to 7%. Citric acid did not show significant leaching of organic components such as carbohydrates and proteins, and represented a less toxic and hazardous option for demineralization. HTL of untreated and citric acid treated Sargassum spp. resulted in bio-oil yields of 18.4±0.1 % and 22.2±0.1 % (ash free dry basis, respectively.

  19. CO2 laser irradiation enhances CaF2 formation and inhibits lesion progression on demineralized dental enamel-in vitro study.

    Science.gov (United States)

    Zancopé, Bruna R; Rodrigues, Lívia P; Parisotto, Thais M; Steiner-Oliveira, Carolina; Rodrigues, Lidiany K A; Nobre-dos-Santos, Marinês

    2016-04-01

    This study evaluated if Carbon dioxide (CO2) (λ 10.6 μm) laser irradiation combined with acidulated phosphate fluoride gel application (APF gel) enhances "CaF2" uptake by demineralized enamel specimens (DES) and inhibits enamel lesion progression. Thus, two studies were conducted and DES were subjected to APF gel combined or not with CO2 laser irradiation (11.3 or 20.0 J/cm(2), 0.4 or 0.7 W) performed before, during, or after APF gel application. In study 1, 165 DES were allocated to 11 groups. Fluoride as "CaF2 like material" formed on enamel was determined in 100 DES (n = 10/group), and the surface morphologies of 50 specimens were evaluated by scanning electron microscopy (SEM) before and after "CaF2" extraction. In study 2, 165 DES (11 groups, n = 15), subjected to the same treatments as in study 1, were further subjected to a pH-cycling model to simulate a high cariogenic challenge. The progression of demineralization in DES was evaluated by cross-sectional microhardness and polarized light microscopy analyses. Laser at 11.3 J/cm(2) applied during APF gel application increased "CaF2" uptake on enamel surface. Laser irradiation and APF gel alone arrested the lesion progression compared with the control (p enamel surface and a synergistic effect was found. However, regarding the inhibition of caries lesion progression, no synergistic effect could be demonstrated. In conclusion, the results have shown that irradiation with specific laser parameters significantly enhanced CaF2 uptake by demineralized enamel and inhibited lesion progression.

  20. Artificial Limbs

    Science.gov (United States)

    ... you are missing an arm or leg, an artificial limb can sometimes replace it. The device, which ... activities such as walking, eating, or dressing. Some artificial limbs let you function nearly as well as ...

  1. Validation of a Cariogenic Biofilm Model to Evaluate the Effect of Fluoride on Enamel and Root Dentine Demineralization.

    Science.gov (United States)

    Fernández, Constanza E; Tenuta, Livia M A; Cury, Jaime A

    2016-01-01

    Due to gingival recession both enamel and root dentine are at risk of developing caries. Both tissues are exposed to a similar environment, however there is not a validated model to evaluate the effect of fluoride on these dental substrates simultaneously. Hence, this study aimed to validate a caries model to evaluate the effect of fluoride to prevent demineralization on enamel and root-dentine. Streptococcus mutans UA159 biofilms were formed on saliva-coated bovine enamel and root dentine slabs (n = 12 per group) mounted in the same well of culture plates. The biofilms were exposed 8×/day to 10% sucrose and treated 2×/day with fluoridated solutions containing 0, 150, 450, or 1,350 ppm F; thus, simulating the use of low to high fluoride concentration toothpastes. The pH values of the culture medium was monitored 2×/day as a biofilm acidogenicity indicator. After 96 h, biofilms were collected for fluoride concentration analysis. The percentage of surface hardness loss (%SHL) was calculated for slabs. The fluoride uptake by the enamel and dentine was also determined. The model showed a dose-response because the biofilm and fluoride uptake increased and %SHL decreased at increasing fluoride concentrations (p enamel. With the same fluoride concentration treatment, the percentage of reduction of demineralization was lower for dentine than for enamel. In conclusion, the model was validated in terms of a dose-response effect of fluoride on enamel and root dentine. Furthermore, the findings support the clinical data, suggesting that higher fluoride concentrations are necessary to control caries of root dentine than of enamel.

  2. Sodium trimetaphosphate enhances the effect of 250 p.p.m. fluoride toothpaste against enamel demineralization in vitro.

    Science.gov (United States)

    Missel, Emilene M C; Cunha, Robson F; Vieira, Ana E M; Cruz, Nathália V S; Castilho, Flavia C N; Delbem, Alberto C B

    2016-08-01

    This in vitro study investigated the effect of sodium trimetaphosphate (TMP), added to toothpaste containing 250 p.p.m. fluoride, on enamel demineralization. Bovine enamel blocks (n = 96) were subjected to five pH cycles over a 7-d period and treatment with suspensions of toothpastes containing 0, 250, 500, and 1,100 p.p.m. fluoride (as sodium fluoride), as well as with 250 p.p.m. fluoride containing TMP at 0.25, 0.5, 1.0, and 3.0%. Treatment with toothpaste suspensions was performed under agitation twice a day, for 1 min. Surface and cross-sectional hardness, and fluoride firmly bound to enamel, were quantified. Data were subjected to one-way anova, followed by Tukey's test. Low-fluoride toothpastes containing TMP at 0.25-1.0% resulted in enamel mineral loss similar to that seen for the toothpaste containing 1,100 p.p.m. fluoride. Also, the addition of TMP to the toothpaste containing 250 p.p.m. fluoride promoted enamel fluoride concentrations similar to those obtained for the 500 p.p.m. fluoride group. The toothpaste containing 250 p.p.m. fluoride and 0.25% TMP led to the lowest mineral loss among all groups. It was concluded that the addition of as little as 0.25% TMP to a toothpaste containing 250 p.p.m. fluoride can reduce enamel demineralization to levels similar to those seen for a conventional toothpaste containing 1,100 p.p.m. fluoride, in vitro. PMID:27198971

  3. Calcium Prerinse before Fluoride Rinse Reduces Enamel Demineralization: An in situ Caries Study.

    Science.gov (United States)

    Souza, João Gabriel S; Tenuta, Livia Maria Andaló; Del Bel Cury, Altair Antoninha; Nóbrega, Diego Figueiredo; Budin, Renan R; de Queiroz, Mateus X; Vogel, Gerald L; Cury, Jaime A

    2016-01-01

    A calcium (Ca) prerinse before a fluoride (F) rinse has been shown to increase oral F levels. We tested the anticaries effect of this combination in a dose-response in situ caries model. In a double-blind, crossover experiment, 10 volunteers carried enamel slabs in palatal appliances for 14 days, during which they rinsed twice/day with one of four rinse combinations: (1) a placebo prerinse (150 mM sodium lactate) followed by a distilled water rinse (negative control); (2) a placebo prerinse followed by a 250 ppm F rinse; (3) a placebo prerinse followed by a 1,000 ppm F rinse, or (4) a Ca prerinse (150 mM Ca, as calcium lactate) followed by a 250 ppm F rinse. Sucrose solution was dripped onto the slabs 8×/day to simulate a high cariogenic challenge. The percent surface hardness loss (%SHL) was significantly lower in the Ca prerinse used with the 250 ppm F rinse group (%SHL = 38.0 ± 21.0) when compared with the F rinse alone (%SHL = 59.5 ± 24.1) and similar to the 1,000 ppm F rinse group (%SHL = 42.0 ± 18.3). Compared with the 250 ppm F rinse, the Ca prerinse increased biofilm fluid F only twice (nonsignificant). However, it greatly increased F in biofilm solids (∼22×). The Ca prerinse had little effect on loosely or firmly bound enamel F. The results showed an increased level of protection against demineralization by the use of a Ca prerinse, which seems to be caused by the enhancement of F concentration in the biofilm. PMID:27355353

  4. Ablation from artificial or laser-induced crater surfaces of silver by laser irradiation at 355 nm

    DEFF Research Database (Denmark)

    Toftmann, B.; Schou, Jørgen; Larsen, N.B.

    1999-01-01

    The angular distribution of laser ablated particles from silver irradiated at 355 nm has been studied. The angular distribution from craters prepared by more than 10(4) shots exhibits only minor changes compared with that from a nonirradiated target. The distribution from artificial cylindrical...... craters of a depth comparable to the laser spot dimensions is about one order of magnitude smaller at large exit angles than that from a flat target....

  5. A three-species biofilm model for the evaluation of enamel and dentin demineralization.

    Science.gov (United States)

    Cavalcanti, Yuri Wanderley; Bertolini, Martinna Mendonça; da Silva, Wander José; Del-Bel-Cury, Altair Antoninha; Tenuta, Livia Maria Andaló; Cury, Jaime Aparecido

    2014-01-01

    Although Streptococcus mutans biofilms have been useful for evaluating the cariogenic potential of dietary carbohydrates and the effects of fluoride on dental demineralization, a more appropriate biofilm should be developed to demonstrate the influence of other oral bacteria on cariogenic biofilms. This study describes the development and validation of a three-species biofilm model comprising Streptococcus mutans, Actinomyces naeslundii, and Streptococcus gordonii for the evaluation of enamel and dentin demineralization after cariogenic challenges and fluoride exposure. Single- or three-species biofilms were developed on dental substrata for 96 h, and biofilms were exposed to feast and famine episodes. The three-species biofilm model produced a large biomass, mostly comprising S. mutans (41%) and S. gordonii (44%), and produced significant demineralization in the dental substrata, although enamel demineralization was decreased by fluoride treatment. The findings indicate that the three-species biofilm model may be useful for evaluating the cariogenic potential of dietary carbohydrates other than sucrose and determining the effects of fluoride on dental substrata. PMID:24730462

  6. Nanometeric hydroxyapatite in situ formed in demineralized bone matrix by electrochemical technique

    Institute of Scientific and Technical Information of China (English)

    CHEN Ji-da; WANG Yuan-ling; CAI Hao-xi; CAO Yin

    2001-01-01

    @@ To prepare biomimic bone materials, some thick meshes of demineralized bone matrix (DBM), which are the interest work of collagen fibrils, have been prepared in normal way, and calcium phosphate of nanometeric apatite-li.ke was introduced into these mesh works with aqueous calcium and phosphate salt solution by means of the electrochemical technique at room temperature.

  7. A simple model for the effect of flouride ions on remineralization of partly demineralized tooth enamel

    Science.gov (United States)

    Christoffersen, J.; Christoffersen, M. R.; Arends, J.

    1984-06-01

    A model is presented for remineralization of partly demineralized tooth enamel, taking the effect of the presence of fluoride ions into account. The model predicts that, in the absence of precipitation of other phases than calcium hydroxyapatite (HAP) and fluroridized HAP, which are assumed to model enamel, there exists a maximum value of the fluoride concentration gradient, above which lesions cannot be successfully repaired.

  8. Comparison Study of Water Demineralization System for the OPR 1000 and AP 1000 Nuclear Power Plant

    International Nuclear Information System (INIS)

    OPR 1000 adopts demineralization method based on ion exchanger resin and AP 1000 adopt the method that based on Reverse Osmosis (RO)-Electrodeionization (EDI). The Ion exchange process is a reversible chemical reaction of a solution and an insoluble solid. Ion exchanger use resin as polluter ions capture and will be regenerated after its saturated. RO is method using pressure to force a solution through a membrane, retaining the solute on one side and allowing the pure solvent to pass to the other side. Whereas, EDI is a combination of ion exchange and electrodialysis. The ions is taken by ion exchange resin, and then it is discharged utilizing electric potential difference. Due to water splitting phenomena in EDI, make resin will never be saturated, so the RO-EDI process is water demineralization system that use little chemical, more simple installation, capable to maintain demineralization water product quality and environmental friendly. Thereby, The RO-EDI water demineralization system is more advance then ion exchange technology. (author)

  9. An alternative treatment option for a bony defect from large odontoma using recycled demineralization at chairside.

    Science.gov (United States)

    Lee, JuHyon; Lee, Eun-Young; Park, Eun-Jin; Kim, Eun-Suk

    2015-04-01

    Odontoma is the most common odontogenic benign tumor, and the treatment of choice is generally surgical removal. After excision, bone grafts may be necessary depending on the need for further treatment, or the size and location of the odontoma. Although the osteogenic capacity of a demineralized tooth was verified as early as 1967 by Urist and many other investigators, the cumbersome procedure, including a long demineralization time, may be less than comfortable for clinicians. A modified ultrasonic technology, with periodic negative pressure and temperature control, facilitated rapid and aseptic preparation of demineralized teeth for bone grafts. This approach reduces the demineralization time dramatically (≤80 minutes), so that the graft material can be prepared chairside on the same day as the extraction. The purpose of this article is to describe two cases of large compound odonotomas used as graft material prepared chairside for enucleation-induced bony defects. These two clinical cases showed favorable wound healing without complications, and good bony support for future dental implants or orthodontic treatment. Finally, this report will suggest the possibility of recycling the benign pathologic hard tissue as an alternative treatment option for conventional bone grafts in clinics.

  10. Fouling control mechanisms of demineralized water backwash: Reduction of charge screening and calcium bridging effects

    KAUST Repository

    Li, Sheng

    2011-12-01

    This paper investigates the impact of the ionic environment on the charge of colloidal natural organic matter (NOM) and ultrafiltration (UF) membranes (charge screening effect) and the calcium adsorption/bridging on new and fouled membranes (calcium bridging effect) by measuring the zeta potentials of membranes and colloidal NOM. Fouling experiments were conducted with natural water to determine whether the reduction of the charge screening effect and/or calcium bridging effect by backwashing with demineralized water can explain the observed reduction in fouling. Results show that the charge of both membranes and NOM, as measured by the zeta potential, became more negative at a lower pH and a lower concentration of electrolytes, in particular, divalent electrolytes. In addition, calcium also adsorbed onto the membranes, and consequently bridged colloidal NOM and membranes via binding with functional groups. The charge screening effect could be eliminated by flushing NOM and membranes with demineralized water, since a cation-free environment was established. However, only a limited amount of the calcium bridging connection was removed with demineralized water backwashes, so the calcium bridging effect mostly could not be eliminated. As demineralized water backwash was found to be effective in fouling control, it can be concluded that the reduction of the charge screening is the dominant mechanism for this. © 2011 Elsevier Ltd.

  11. A three-species biofilm model for the evaluation of enamel and dentin demineralization.

    Science.gov (United States)

    Cavalcanti, Yuri Wanderley; Bertolini, Martinna Mendonça; da Silva, Wander José; Del-Bel-Cury, Altair Antoninha; Tenuta, Livia Maria Andaló; Cury, Jaime Aparecido

    2014-01-01

    Although Streptococcus mutans biofilms have been useful for evaluating the cariogenic potential of dietary carbohydrates and the effects of fluoride on dental demineralization, a more appropriate biofilm should be developed to demonstrate the influence of other oral bacteria on cariogenic biofilms. This study describes the development and validation of a three-species biofilm model comprising Streptococcus mutans, Actinomyces naeslundii, and Streptococcus gordonii for the evaluation of enamel and dentin demineralization after cariogenic challenges and fluoride exposure. Single- or three-species biofilms were developed on dental substrata for 96 h, and biofilms were exposed to feast and famine episodes. The three-species biofilm model produced a large biomass, mostly comprising S. mutans (41%) and S. gordonii (44%), and produced significant demineralization in the dental substrata, although enamel demineralization was decreased by fluoride treatment. The findings indicate that the three-species biofilm model may be useful for evaluating the cariogenic potential of dietary carbohydrates other than sucrose and determining the effects of fluoride on dental substrata.

  12. THE EFFECTS OF A SODIUM-HYPOCHLORITE TREATMENT ON DEMINERALIZED ROOT DENTIN

    NARCIS (Netherlands)

    INABA, D; DUSCHNER, H; JONGEBLOED, W; ODELIUS, H; TAKAGI, O; ARENDS, J

    1995-01-01

    The effects of a 10% NaOCl treatment for 2 min on demineralized human root dentin were investigated by means of: microradiography (MR), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and secondary ion mass spectroscopy (SIMS). MR measurements revealed that NaOCl caused

  13. Rachitic Changes, Demineralization, and Fracture Risk in Healthy Infants and Toddlers with Vitamin D Deficiency

    Science.gov (United States)

    Feldman, Henry A.; Kleinman, Paul K.; Connolly, Susan A.; Fair, Rick A.; Myers, Regina M.; Gordon, Catherine M.

    2012-01-01

    Purpose: To examine radiographic findings in children with vitamin D deficiency in comparison with biochemical marker levels and prevalence of fractures. Materials and Methods: The parents or guardians of all participants provided written informed consent at the time of enrollment. The institutional review board approved the protocol, and HIPAA guidelines were followed. From a prospective sample of children seen for routine clinical care, 40 children with vitamin D deficiency (25-hydroxyvitamin D [25-OHD] level, ≤20 ng/mL) were identified, and high-detail computed radiographs of the wrists and knees were obtained. The children ranged in age from 8 to 24 months. Radiographs were scored by three readers with use of the 10-point Thacher score for rachitic changes and a five-point scale for demineralization. Serum calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels were determined. Fracture history was obtained for 35 of the 40 patients (88%). Results: All readers identified rachitic changes at both readings in two patients (5%) and demineralization in two patients (5%). Interrater agreement was 65% for rachitic changes (κ = 0.33) and 70% for demineralization (κ = 0.37). When the majority of the raters determined that rachitic changes were absent at both readings, alkaline phosphatase levels were lower than those with other assessments (median, 267 vs 515 U/L [4.4589 vs 8.6005 μkat/L]; P = .01). When most raters determined that demineralization was present at both readings, serum 25-OHD levels were lower than those at other assessments (median, 9.0 vs 17.5 ng/mL [22.464 vs 43.68 nmol/L]; P = .02). No fractures were reported or identified radiographically. Conclusion: In infants and toddlers with vitamin D deficiency, rachitic changes and definite demineralization are uncommon and fracture risk is low. © RSNA, 2011 PMID:22106354

  14. The effect of undissociated acetic-acid concentration of buffer solutions on artificial caries-like lesion formation in human tooth enamel

    NARCIS (Netherlands)

    Groeneveld, A.; Theuns, H.M.; Dijk, J.W.E. van; Driessens, F.C.M.

    1984-01-01

    A chemical system for lesion production was used. The influence on lesion characteristics of the concentration of undissociated acetic acid in a calcium and phosphate-containing buffer solution was investigated. Artificial lesions obtained after demineralization in buffers with a pH of 4.0, 4.5, 5.0

  15. Availability of Surface Water of Wadi Rajil as a Source of Groundwater Artificial Recharge: A Case Study of Eastern Badia /Jordan

    Directory of Open Access Journals (Sweden)

    Rakad A. Ta'any

    2013-08-01

    Full Text Available Wadi Rajil catchment area is considered as one of the major wadis entering the Azraq Basin from the north. It is ungauged wadi and covers an area of about 3910km2. The annual average rainfall on Wadi Rajil catchment area is about 126.6mm. Heavy thunderstorms occur in April and May, causing significant floods covering the area. The flood waters are not utilized, and a small portion infiltrates into the ground, where the great portion of these waters remain over Qaa’ Azraqfew months before evaporation. Due to the absence of the hydrometric stream flow station, no data are available about surface water runoff in Wadi Rajil catchment area. Therefore, the first part of this study calculates the surface water potential of Wadi Rajil to be utilized for groundwater artificial recharge, applying the SCS curvilinear synthetic unit hydrograph method. The synthesis unit hydrograph of Wadi Rajil catchment is characterized by a peak value of 1146 m3/s (4047 cfs per one inch of rainfall excess. Flood hydrographs for 10,25,50, and 100 years return periods were derived and their peak flow are found to be 10,8,186,412, and 680 m3/s, respectively and the corresponding flood volumes are 0.95, 16.53, 36.89, and 61.5 MCM, respectively.Groundwater artificial recharge conditions are suitably prevailing in the most northern and central part of the catchment area, whereas, geological, Hydrogeological, and water quality characteristics of the floodwater encourage artificial replenishment of the exploited aquifer in the study area.

  16. 酪蛋白磷酸肽-磷酸钙溶液抑制牛牙早期釉质龋的体外研究%Study on Effect of CPP-ACP in Inhibiting Bovine Enamel Demineralization in vitro

    Institute of Scientific and Technical Information of China (English)

    王伟萍; 卢友光; 冯岩

    2011-01-01

    Objective To investigate the effect of casein phosphopeptide-stabilized amorphous cal cium phosphate solution (CPP-ACP) in inhibiting bovine enamel demineralization in vitro. Methods Twenty-eight enamel pieces -were randomly divided into four groups(n=7) , and immersed in saliva for 24 hours to obtain acquired pellicle. Each group -was given different treatments (Group A: deionized water; Group B: 1% CPP-ACP; Group C: 0. 05% NaF; Group D: 1% CPP-ACP+0. 05% NaF) for 7 days, and immersed in fresh streptococcus mutans solution for 7 days to produce artificial caries. Finally, all sam ples were detected by the scanning electron microscope(SEM) and the surface microhardness(SMH) ma chine. Results The SEM showed lots of sizes concane on the enamel surface of group A. While the en amel surface of the other three groups were completed, and a large number of deposits were found on the surfaces. The SMH of groups B,C and D were higher than group A(P<0. 05). In groups B,C and D, there were significant differences bet ween each other(P<0. 05). Conclusion CPP-ACP can reduce en amel demineralization and promoting remineralization in vitro. CPP-ACP and NaF have synergistic effect in caries prevention.%目的 研究酪蛋白磷酸肽-磷酸钙溶液(CPP-ACP)在体外对牛牙釉质早期人工龋的抑制作用.方法 将28颗牛牙釉质样本随机分成4组,每组7颗,浸入唾液24 h以形成人工获得性膜,然后用4种不同溶液(A组:去离子水;B组:1% CPP-ACP溶液;C组:0.05%的NaF溶液;D组:1% CPP-ACP和0.05% NaF的混合液)浸泡7 d后,将其悬吊在新鲜配制的变异链球菌悬液中7 d,建立体外生物膜脱矿模型.采用扫描电镜观察处理前后牙釉质表面形态的改变,采用显微硬度法测量处理前后牙釉质表面硬度.结果 扫描电镜下,A组釉质表面可见大小不等的圆形孔隙,呈蜂窝状改变;其他3组釉质表面完整,没有明显的龋损孔隙,可见不规则的矿物质沉积.显微硬度测量显示,B、C

  17. Commissioning of the water demineralization plant of Atucha II Nuclear Power Plant

    International Nuclear Information System (INIS)

    In Argentina there are two operating Nuclear Power Reactors and a third one is being constructed. Embalse NPP is a 648 Mwe CANDU®-600 type pressurized heavy water reactor (PHWR), designed and built by Atomic Energy of Canada (AECL) and in commercial operation since 1984. Atucha I is a Pressurized Vessel Heavy Water Reactor (PVHWR) of 340 Mwe, in operation since 1974, and Atucha II (also PHWR) of 740 Mwe is in advanced construction state, both of them designed by SIEMENS-KWU. All of these Nuclear Power Plants are operated by Nucleoelectrica Argentina (N.A.S.A.). The Comision Nacional de Energia Atomica (C.N.E.A.) is the R and D nuclear institution in the country that, among many other topics, provides technical support to the plants. Although the Atucha II project has suffered some years of delay, pressure tests are expected to be carried out by the end of the year 2010 and in that sense, water chemistry related activities, specifications, chemistry manuals, laboratories organization and personnel training are acquiring importance. The demineralized water needed for the secondary and auxiliary systems is obtained by means of a demineralization plant, which purifies water from Parana River up to nuclear grade. This plant was designed by Degremont in 1979 and consists of a preliminary treatment by coagulation - flocculation and gravel filters, and subsequent demineralization with ion exchange resins. For the commissioning of the demineralization plant, preliminary tests in the chemical laboratory are performed. The flocculator is simulated using a Jar-Test, different coagulants and coagulation aids are tested with the objective of selecting the best product and defining its optimum dosage. The coagulated water is filtered by means of a funnel with filtration paper and sand. The clarified water thus obtained is treated by ion exchange resins, the train consisting of a cationic, an anionic and a mixed bed. The purpose of the laboratory experiments is to test the resins

  18. Artificial blood

    Directory of Open Access Journals (Sweden)

    Sarkar Suman

    2008-01-01

    Full Text Available Artificial blood is a product made to act as a substitute for red blood cells. While true blood serves many different functions, artificial blood is designed for the sole purpose of transporting oxygen and carbon dioxide throughout the body. Depending on the type of artificial blood, it can be produced in different ways using synthetic production, chemical isolation, or recombinant biochemical technology. Development of the first blood substitutes dates back to the early 1600s, and the search for the ideal blood substitute continues. Various manufacturers have products in clinical trials; however, no truly safe and effective artificial blood product is currently marketed. It is anticipated that when an artificial blood product is available, it will have annual sales of over $7.6 billion in the United States alone.

  19. 人工血管材料血液相容性及表面改性%Hemocompatibility and surface modification of artificial blood vessel materials

    Institute of Scientific and Technical Information of China (English)

    何艳平; 马德春; 李磊; 张丽; 郑爽; 董可欣

    2015-01-01

    BACKGROUND:Artificial blood vessels made from synthetic materials are the most commonly used blood vessel substitutes. How to improve the patency of the blood vessels and the compatibility of artificial blood vessel materials is in the focus of research in recent years. OBJECTIVE:To review the biocompatibility and hemocompatiblity of artificial blood vessel materials, and to summarize a number of new methods and viewpoints appearing in international biomaterial and blood interaction research in recent years. METHODS: Wanfang database, Chinese Journal Ful-text Database and PubMed database were retrieved by the first author for relevant articles published from 2001 to 2014, using the key words of “artificial blood vessels, biomaterials” in Chinese and English, respectively. RESULTS AND CONCLUSION: Research on the hemocompatibility of materials, although after many years, is stil in the exploratory stage. There are many factors influencing material hemocompatibility, and in addition to the inherent blood components, surface and interface characteristics of the materials play a decisive role. Currently, surface and interface features optimization and modification has become an important way to improve the blood compatibility, but the existing evaluation system appears to have some problems, such as the selection and quantitative evaluation of sensitive indicators and positive control materials. Therefore, to develop artificial materials with good hemocompatibility and to establish rational and high-efficient blood compatibility evaluation system stil need further studies.%背景:人工血管取于合成材料,是最常用的血管代用品,如何提高血管的通畅性和人工血管材料的相容性是在近年来人工血管研究的重点。目的:综述人工血管材料的生物相容性和血液相容性,归纳近年来国际在生物材料和血液相互作用研究方面出现的一些新方法和视点。方法:由第一作者用计算机检

  20. Detection for demineralization of dental hard tissues using index-sequenced radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dong Hyun; Park, Young Ho; Kim, Kyung Sook; Park, Jeong Hoon; Lee, Gi Ja; Choi, Sam Jin; Park, Hun Kuk [Department of Biomedical Engineering, School of Medicine, KyungHee University, Seoul (Korea, Republic of); Choi, Yong Suk; Hwang, Eui Hwan [Department of Oral and Maxillofacial Radiology, Institute of Oral Biology, School of Dentistry, KyungHee University, Seoul (Korea, Republic of)

    2009-06-15

    The purpose of this study was to develop the radiographic technique for detecting the demineralization which is known as indication of dental caries. This technique was based on the comparing of multiple radiographs which was irradiated by multiple X-ray spectra. For the meaningful comparing, the multiple radiographs were reconstructed to the dosimetrically consistent images using a standard material. The difference of resulting images of same target with multiple spectra represents the difference of response of material as regards the spectra. We have found about 10% of demineralization of dental hard tissues particularly in the proximal region through the analyzing of differences. Most intriguing thing in this investigation was that the method to analyze difference shows us to an anatomic structure of dental hard tissues even if absolute values of optical density were excluded during the procedures.

  1. Artificial intelligence

    CERN Document Server

    Ennals, J R

    1987-01-01

    Artificial Intelligence: State of the Art Report is a two-part report consisting of the invited papers and the analysis. The editor first gives an introduction to the invited papers before presenting each paper and the analysis, and then concludes with the list of references related to the study. The invited papers explore the various aspects of artificial intelligence. The analysis part assesses the major advances in artificial intelligence and provides a balanced analysis of the state of the art in this field. The Bibliography compiles the most important published material on the subject of

  2. Orthodontic Cements and Demineralization: An In Vitro Comparative Scanning Electron Microscope Study

    OpenAIRE

    Prabhavathi, V; Jacob, Josy; Kiran, M. Shashi; Ramakrishnan, Murugesan; Sethi, Esha; Krishnan, C S

    2015-01-01

    Background: Comparison of the demineralization potential of four luting cements, i.e. zinc phosphate, conventional glass ionomer cement (GIC), resin-modified GIC and acid modified composite resin. Materials and Methods: This study was conducted on 75 extracted premolar teeth, which were grouped into five, each group containing 15 teeth. Groups were non-banded control, teeth cemented with the above-mentioned cements. These were incubated at 37°C for 30 days in sealable plastic containers, afte...

  3. A comparison of commercially available demineralized bone matrix for spinal fusion

    OpenAIRE

    Wang, Jeffrey C.; Alanay, A; Mark, Davies; Kanim, Linda E. A.; Campbell, Pat A; Dawson, Edgar G.; Lieberman, Jay R.

    2007-01-01

    In an effort to augment the available grafting material as well as to increase spinal fusion rates, the utilization of a demineralized bone matrix (DBM) as a graft extender or replacement is common. There are several commercially available DBM substances available for use in spinal surgery, each with different amounts of DBM containing osteoinductive proteins. Each product may have different osteoinductivity potential due to different methods of preparation, storage, and donor specifications....

  4. Nondestructive Assessment of Early Tooth Demineralization Using Cross-Polarization Optical Coherence Tomography

    OpenAIRE

    Kang, Hobin; Jiao, Jian J.; Lee, Chulsung; Le, Michael H.; Darling, Cynthia L.; Fried, Daniel

    2010-01-01

    New methods are needed for the nondestructive measurement of tooth demineralization and remineralization to monitor the progression of incipient caries lesions (tooth decay) for effective nonsurgical intervention and to evaluate the performance of anticaries treatments such as chemical treatments or laser irradiation. Studies have shown that optical coherence tomography (OCT) has great potential to fulfill this role since it can be used to measure the depth and severity of early lesions with ...

  5. Monitoring tooth demineralization using a cross polarization optical coherence tomographic system with an integrated MEMS scanner

    OpenAIRE

    Fried, Daniel; Staninec, Michal; Darling, Cynthia; Kang, Hobin; Chan, Kenneth

    2012-01-01

    New methods are needed for the nondestructive measurement of tooth demineralization and remineralization to monitor the progression of incipient caries lesions (tooth decay) for effective nonsurgical intervention and to evaluate the performance of anti-caries treatments such as chemical treatments or laser irradiation. Studies have shown that optical coherence tomography (OCT) has great potential to fulfill this role since it can be used to measure the depth and severity of early lesions with...

  6. Design and construction of demineralized water production and maintenance system for RA-O nuclear reactor

    International Nuclear Information System (INIS)

    The normal operation of zero power RA-O Nuclear Reactor requires a production and maintenance of demineralized water system. This system was designed and built-up during the works for actualization, upgrading and new start up at Cordoba National University of this facility. This paper comments the relevant aspects about the didactical purpose of that system and the details considered for training and practices with it. Similarly, considerations about solids wastes and effluents treatment are discussed. (Author)

  7. The effect of depth of dentin demineralization on bond strengths and morphology of the hybrid layer.

    Science.gov (United States)

    Perdigão, J; May, K N; Wilder, A D; Lopes, M

    2000-01-01

    Previous studies have shown that different phosphoric acid-based etchants do not penetrate intertubular dentin to the same depth. The purpose of this study was to determine the effect of different phosphoric acid-based conditioners on dentin shear bond strengths of three one-bottle bonding systems and to evaluate the corresponding interfacial ultramorphology. The null hypothesis to be tested was that no correlation could be established between the depth of intertubular demineralization and dentin shear bond strengths. The labial surface of 90 bovine incisors was polished to expose middle dentin. The specimens were randomly assigned to three one-bottle adhesive systems (n = 30): OptiBond SOLO, Permaquick PQ1, and Single Bond. For each adhesive system the specimens were divided into three subgroups of different silica-thickened etching gels (n = 10): 37.5% phosphoric acid gel (Kerr Gel Etchant), 35% phosphoric acid gel (Ultraetch), and 35% phosphoric acid gel (Scotchbond Etching Gel). After 24 hours in water at 37 degrees C, the specimens were thermocycled for 500 cycles in baths kept at 5 degrees C and 55 degrees C and the shear bond strengths measured. The data were analyzed with one-way and two-way ANOVA. Further, the adhesives were applied to 800 microns-thick bovine dentin disks (two per subgroup), which were restored with a low-viscosity composite resin. Six small dentin/resin sticks with a cross-section of 1.0 mm x 1.0 mm were obtained from each bonded disk. They were then decalcified in a buffered solution of EDTA, fixed, stained, and sectioned in 90 nanometer-thick slices to observe under the Transmission Electron Microscope (TEM). The mean shear bond strengths were not statistically different at a confidence level of 95%. When the means were pooled for dentin adhesive and for etching gel, the number of cohesive failures was greater for Permaquick PQ1 and for Ultraetch, respectively. Pearson's correlation coefficient showed no correlation between hybrid

  8. S. mutans biofilm model to evaluate antimicrobial substances and enamel demineralization

    Directory of Open Access Journals (Sweden)

    Renzo Alberto Ccahuana-Vásquez

    2010-06-01

    Full Text Available The aim of this study was to validate a model of S. mutans biofilm formation, which simulated 'feast-famine' episodes of exposure to sucrose that occur in the oral cavity, showed dose-response susceptibility to antimicrobials and allowed the evaluation of substances with anticaries potential. S. mutans UA159 biofilms were grown for 5 days on bovine enamel slabs at 37°C, 10% CO2. To validate the model, the biofilms were treated 2x/day with chlorhexidine digluconate (CHX at 0.012, 0.024 and 0.12% (concentration with recognized anti-plaque effect and 0.05% NaF (concentration with recognized anti-caries effect. CHX showed dose-response effect decreasing biomass, bacterial viability and enamel demineralization (p < 0.05. Whereas, 0.05% NaF did not show antimicrobial effect but had similar effect to that of 0.12% CHX decreasing enamel demineralization (p < 0.05. The model developed has potential to evaluate the effect of substances on biofilm growth and on enamel demineralization.

  9. Surface modification of polyurethane films by plasma and ultraviolet light to improve haemocompatibility for artificial heart valves.

    Science.gov (United States)

    Alves, P; Cardoso, R; Correia, T R; Antunes, B P; Correia, I J; Ferreira, P

    2014-01-01

    Prosthetic cardiac valves implantation is a common procedure used to treat heart valve diseases. Although there are different prostheses already available in the market (either mechanical or bioprosthetic), their use presents several problems, specifically concerning thrombogenicity and structural failure. Recently, some progresses have been achieved in developing heart valves based on synthetic materials with special emphasis in polymers. Among them, polyurethanes are one of the most commonly used for the production of these devices. Herein, Elastollan(®)1180A50, a thermoplastic polyurethane (TPU), was used to formulate films whose surfaces were modified by grafting 2-hydroxyethylmethacrylate (HEMA) either by ultra-violet (UV) or by plasma treatment. All films were analyzed before and after grafting. X-ray photoelectron spectroscopy (XPS) measurements were used to evaluate TPU surfaces functionalization. HEMA grafting was confirmed by the increase of the hydroxyl (OH) groups' concentration at the surface of the films. Atomic force microscopy (AFM) analysis was done to evaluate the surface topography of the biomaterials. Results showed that the roughness of the surface decreased when HEMA was grafted, especially for plasma treated samples. After grafting the films' hydrophilicity was improved, as well as the polar component of the surface energy, by 15-30%. Hydrophobic recovery studies using milli Q water or PBS were also performed to characterize the stability of the modified surface, showing that the films maintained their surface properties along time. Furthermore, blood-contact tests were performed to evaluate haemolytic and thrombogenic potential. The results obtained for HEMA grafted surfaces, using plasma treatment, confirmed biomaterials biocompatibility and low thrombogenicity. Finally, the cytotoxicity and antibacterial activity of the materials was assessed through in vitro assays for both modified films. The obtained results showed enhanced

  10. Artificial Reefs

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An artificial reef is a human-made underwater structure, typically built to promote marine life in areas with a generally featureless bottom, control erosion, block...

  11. Development of Bacterial Biofilms on Artificial Corals in Comparison to Surface-Associated Microbes of Hard Corals

    OpenAIRE

    Michael John Sweet; Aldo Croquer; John Christopher Bythell

    2011-01-01

    Numerous studies have demonstrated the differences in bacterial communities associated with corals versus those in their surrounding environment. However, these environmental samples often represent vastly different microbial micro-environments with few studies having looked at the settlement and growth of bacteria on surfaces similar to corals. As a result, it is difficult to determine which bacteria are associated specifically with coral tissue surfaces. In this study, early stages of passi...

  12. Impact of gravity, collector surface roughness and fracture orientation on colloid retention kinetics in an artificial fracture.

    Science.gov (United States)

    Stoll, M; Huber, F M; Darbha, G K; Schill, E; Schäfer, T

    2016-08-01

    The interaction of monodisperse fluorescent carboxylated polystyrene colloids (25nm and 1000nm diameter) with a cut granodiorite surface (Grimsel granodiorite; Switzerland) and with acrylic glass is investigated both experimentally and numerically. Colloid transport experiments are conducted in a parallel plate type fracture flow cell with an aperture of 0.75mm at pH5 under low ionic strength (1mM NaCl) and under laminar flow (7mL/h) conditions. The study focuses on the effect of residence time, colloid size, collector material and fracture orientation on colloid retention. Long colloid residence times are achieved by stop-flow experiments. Using atomic force microscopy and, more specifically, the colloid probe technique surface roughness and force distance information of the collector material (granodiorite or acrylic glass) as a function of probe size (cantilever) are obtained. The experiments are modeled using COMSOL Multiphysics® (2-D numerical simulations). The experimental and the modeled results lead to the conclusion that large colloids (1000nm diameter) undergo sedimentation and deposition on the surface during stop-flow. Collector interaction is not affected by the surface roughness variation. Contrariwise, for the investigated 25nm colloids sedimentation does not play a role under the experimental conditions and collector interaction is triggered by surface inhomogeneities such as surface roughness. PMID:27174623

  13. Surface photo-discoloration and degradation of dyed wood veneer exposed to different wavelengths of artificial light

    International Nuclear Information System (INIS)

    Highlights: • Investigate the selective absorption of different wavelengths of UV–vis light by dyed wood chromophores. • Identify connection between light wavelengths and surface color changes and chemical structure degradation. • Study hypochromic effect based on surface reflectance and K/S absorption changes during UV–vis irradiation. - Abstract: The surface of dyed wood is prone to discoloration when exposed to light irradiation which significantly decreases its decorative effect and shortens its service life. The influence of light wavelength exposure to the surface of dyed wood was investigated to study the effect on discoloration and degradation. Acid Blue V and Acid Red GR dyed wood veneers were subjected to light exposure with different wavelengths from the UV to visible region (254–420 nm). Results showed that the surface discoloration of dyed wood was linearly related to lignin concentration and dyes degradation and the consequent transformation of chromophoric groups such as aromatic (C=C) and carbonyl (C=O) through methoxy reaction. The dyes, lignin and some active constituents were degraded severely, even at short exposures. Acid Blue V dyed wood exhibited greater discoloration than the Acid Red GR treatment. The reflectance and K/S absorption curve showed a hypochromic effect on the dyed wood surface. The dyes and wood chemical structure played a complex and combined role on the selective absorption of different wavelengths of light. The color change rate was apparent with 254 nm exposure in the initial stages, but a greater discoloration rate occurred on the samples irradiated at 313 and 340 nm than at 254 and 420 nm with the time prolonged. The degradation rate and degree of discoloration correlated well with the light energy and wavelength

  14. Comparison of Cultural and Molecular Fecal Indicator Measurements in Surface Water and Periphyton Biofilms in Artificial Streams

    Science.gov (United States)

    Studies suggest that periphyton in streambeds can harbor fecal indicator bacteria (FIB) and, under certain circumstances, can be transferred from the periphyton biofilm into the surface water. An indoor mesocosm study was conducted at the U.S. Environmental Protection Agency Expe...

  15. Surface photo-discoloration and degradation of dyed wood veneer exposed to different wavelengths of artificial light

    Science.gov (United States)

    Liu, Yi; Shao, Lingmin; Gao, Jianmin; Guo, Hongwu; Chen, Yao; Cheng, Qingzheng; Via, Brian K.

    2015-03-01

    The surface of dyed wood is prone to discoloration when exposed to light irradiation which significantly decreases its decorative effect and shortens its service life. The influence of light wavelength exposure to the surface of dyed wood was investigated to study the effect on discoloration and degradation. Acid Blue V and Acid Red GR dyed wood veneers were subjected to light exposure with different wavelengths from the UV to visible region (254-420 nm). Results showed that the surface discoloration of dyed wood was linearly related to lignin concentration and dyes degradation and the consequent transformation of chromophoric groups such as aromatic (Cdbnd C) and carbonyl (Cdbnd O) through methoxy reaction. The dyes, lignin and some active constituents were degraded severely, even at short exposures. Acid Blue V dyed wood exhibited greater discoloration than the Acid Red GR treatment. The reflectance and K/S absorption curve showed a hypochromic effect on the dyed wood surface. The dyes and wood chemical structure played a complex and combined role on the selective absorption of different wavelengths of light. The color change rate was apparent with 254 nm exposure in the initial stages, but a greater discoloration rate occurred on the samples irradiated at 313 and 340 nm than at 254 and 420 nm with the time prolonged. The degradation rate and degree of discoloration correlated well with the light energy and wavelength.

  16. [Preparation of Ti-O Film Deposited on the Surface of a New Type of Artificial Mechanical Heart Valve].

    Science.gov (United States)

    Zhou, Feng; Cui, Yuanyuan; Wu, Liangliang; Sun, Hong; Huang, Nan

    2015-04-01

    The rutile structure titanium oxide (Ti-O) film was prepared on the pure titanium material TA2 (99.999%) surface by the magnetic filter high vacuum arc deposition sputtering source. The method can not only maintain the material mechanical properties, but also improve the surface properties for better biocompatibility to accommodate the physiological environment. The preparation process of the Ti-O film was as follows. Firstly, argon ions sputtered to the TA2 substrate surface to remove the excess impurities. Secondly, a metal ion source generated Ti ions and oxygen ions by the RF discharge. Meanwhile a certain negative bias was imposed on the sample. There a certain composition of Ti-O film was obtained under a certain pressure of oxygen in the vacuum chamber. Finally, X-ray diffraction was used to research the structure and composition of the film. The results showed that the Ti-O film of the rutile crystal structure was formed under the 0.18 Pa oxygen partial pressure. A Nano scratch experiment was used to test the coating adhesion property, which demonstrated that the film was stable and durable. The contact angle experiment and the platelet clotting experiment proved that the modified surface method had improved platelet adhesion performance, and, therefore, the material possessed better biocompatibility. On the whole, the evaluations proved the modified material had excellent performance. PMID:26211266

  17. Bioactive glass effects on remineralization of early artificial enamel caries%生物活性玻璃对早期人工釉质龋的再矿化*★

    Institute of Scientific and Technical Information of China (English)

    王尹; 王瑀; 董波; 张婷; 陈思杰; 曲媛媛

    2013-01-01

      背景:生物活性玻璃具有良好的生物相容性,且具有抑制口腔致龋细菌和牙周相关细菌及抗牙本质过敏的作用。目的:评价生物活性玻璃促进早期人工釉质龋再矿化的作用。方法:将新鲜拔除的30颗牛切牙制成人工龋模型,将标本在37℃人工脱矿液内脱矿72 h,用扫描电镜观察脱矿后釉质表面的平滑情况,用显微硬度仪测量脱矿后釉质的显微硬度。然后随机分为3组,每组10个。采用pH循环法模拟人口腔环境,将3组标本分别浸泡在生物活性玻璃溶液、氟化钠溶液及人工唾液内,3次/d,10 min/次,循环浸泡20 d,扫描电镜检测标本脱矿及再矿化情况,用显微硬度计检查牙釉质显微硬度。结果与结论:浸泡在生物活性玻璃溶液中的牙釉质表面较浸泡在其他两溶液中的牙釉质表面光滑平整,无空隙存在;浸泡在生物活性玻璃溶液中的牙釉质表面显微硬度高于浸泡在其他两溶液中的牙釉质表面显微硬度(P <0.05)。说明生物活性玻璃在体外实验中能促进早期釉质龋的再矿化。%BACKGROUND: Bioactive glass has good biocompatibility and could control oral bacteria and protect against dentin hypersensitivity. OBJECTIVE: To evaluate remineralization effect of bioactive glass on early artificial enamel caries. METHODS: Thirty bovine incisors fresh were made to artificial caries models, and were placed in a container with demineralization iquid at 37 ℃ for 72 hours. Micro hardness tester was used to detect hardness value after demineralization, and the enamel surfaces were observed by scanning electron microscope. Then, the samples were randomly divided into three groups, 10 in each group. Using pH cycle way method, the oral environment of human beings was copied. Samples were respectively soaked in bioactive glass solution, sodium fluoride solution and artificial saliva solution, three times a day and 10 minutes

  18. Artificial human vision.

    Science.gov (United States)

    Dowling, Jason

    2005-01-01

    Can vision be restored to the blind? As early as 1929 it was discovered that stimulating the visual cortex of an individual led to the perception of spots of light, known as phosphenes [1] . The aim of artificial human vision systems is to attempt to utilize the perception of phosphenes to provide a useful substitute for normal vision. Currently, four locations for electrical stimulation are being investigated; behind the retina (subretinal), in front of the retina (epiretinal), the optic nerve and the visual cortex (using intra- and surface electrodes). This review discusses artificial human vision technology and requirements, and reviews the current development projects.

  19. PPP和根面脱矿对牙槽骨成骨细胞在病变牙根面附着及增殖的影响%Attachment and proliferation of alveolar bone cells to diseased root surfaces treated with platelet- poor plasma and demineralization in vitro

    Institute of Scientific and Technical Information of China (English)

    张海燕; 杨俊海; 刘琪

    2011-01-01

    目的 观察贫血小板血浆(PPP)和根面脱矿单独及联合应用对人牙槽骨成骨细胞在病变牙根面的附着及增殖的影响.方法 体外培养人牙槽骨成骨细胞,应用梯度密度离心法从人新鲜全血中获取PPP,将因重度牙周病拔除的牙齿制成病变牙根片.经PPP和EDTA脱矿分别和联合处理的病变根片作为实验组,未处理的病变根片作为对照组,分别采用细胞计数法、四唑盐比色法分析细胞在根片上的附着和增殖,扫描电镜观察PPP对根面的附着情况及其上附着的细胞形态.结果 ①PPP能较牢固地附着于病变根面.与对照组比较,实验组牙槽骨成骨细胞的附着和增殖显著强于对照组,(细胞附着:PPP和EDTA单独处理P<0.05,PPP和EDTA联合处理P<0.01;细胞增殖:PPP和EDTA单独处理P>0.05,PPP和EDTA联合处理P<0.05;②扫描电镜显示实验组根片上细胞显示不同程度胞体增大,胞浆突扩展,有的伸出丝状伪足.结论 PPP能牢固地附着于病变根面,PPP和根面脱矿单独和联合处理病变根片能明显加强三种细胞的附着,而PPP和根面脱矿联合处理还有显著的促细胞增殖效应.%Objective To determine whether it is possible to enhance human alveolar bone cells attachment and proliferation to diseased root surfaces of human diseased root surface treated with EDTA and freshly prepared platelet - poor plasma (PPP) from human whole blood. Methods Hu-man alveolar ostblast bone cells ( OB) grew from tissue explants and cells between the 5th and 8th pas-sage in culture were used. PPP were obtained from fresh human whole blood by gradient density cen-trifugation. Periodontal - affected teeth were collected and sectioned to prepare the 4×4×1 mm 3 dis-eased root slices. There were four groups involving in the experiment; the untreated root slices, the root slices treated with EDTA (24% , pH =6. 7) , the root slices treated with PPP alone and treated with EDTA and PPP. The cell

  20. 全光纤OCT量化检出早期釉质龋的研究%Quantification detecting artificial early enamel caries with all All-fiber-OCT system

    Institute of Scientific and Technical Information of China (English)

    姚晖; 李燕妮; 王冠华; 姚晓天; 孟卓; 靳书凤; 梁燕; 张林朴; 刘铁根

    2009-01-01

    Objective To investigate the sensibility of All-fiber opficM coherence tomography(An-fiberOCT)system for early quantification detecting of artificial caries in vitro.Methods Prepared 2 min×3 mm experimental windows in adamant slippery surfaces of 7 fresh uprooted permanent teeth,demineralized the teeth surfacesin the windows area to ereat early stage of artificial caries mould,by aciding the experimental teeth surfaces of 0~120 hours with demineralized liquid(pH4.5)in vitro.Detected the demineralized changes on the experimental teeth surfaces by dental All-fiber-OCT system,which were newly developed by our research group,and compared the detecting resuhs with clinical diotal photomicrography(DPM)and polarimicroscopy(PMS)on the same tooth sample,to checkout the sensibility and feasibility of All-fiber-OGT for early quantification detecting of artificial caries in vitro.Results Our All-fiber-OCT system could accurately detect surface demineralization changes on the experimental windows of artificial dental caries as earlyas 12haciding treatment,earlier than the survey results obtained by DPM;the surface Integrity of the experimental windows decrease progressively with the increasing Aciding hours,while the demineralized depth increased progressively with the increasing aciding hours.It was shown that quantification detectingdata by OCT has hish correlation to those by PMS,There are no significant differences between data obtained from OCT and PMS(P>0.05).Conclusion All-fiber-OCT system could accurately detect early artificial dental caries without trauma in our model.Quantification detecting data of demineralized depth by OCT has hiigh correlation to those by PMS.It has shown exact detection efficacy on enamel early cariesin our experiment and might become a potential new optical detecting technique for early diagnosis,quantifieation process monitoring and early intervention of dental carles in vivo after the All-fiber OCT system further being consummated

  1. Artificial intelligence

    International Nuclear Information System (INIS)

    A vivid example of the growing need for frontier physics experiments to make use of frontier technology is in the field of artificial intelligence and related themes. This was reflected in the second international workshop on 'Software Engineering, Artificial Intelligence and Expert Systems in High Energy and Nuclear Physics' which took place from 13-18 January at France Telecom's Agelonde site at La Londe des Maures, Provence. It was the second in a series, the first having been held at Lyon in 1990

  2. Artificial Intelligence

    CERN Document Server

    Warwick, Kevin

    2011-01-01

    if AI is outside your field, or you know something of the subject and would like to know more then Artificial Intelligence: The Basics is a brilliant primer.' - Nick Smith, Engineering and Technology Magazine November 2011 Artificial Intelligence: The Basics is a concise and cutting-edge introduction to the fast moving world of AI. The author Kevin Warwick, a pioneer in the field, examines issues of what it means to be man or machine and looks at advances in robotics which have blurred the boundaries. Topics covered include: how intelligence can be defined whether machines can 'think' sensory

  3. Optimization of Burr size, Surface Roughness and Circularity Deviation during Drilling of Al 6061 using Taguchi Design Method and Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Reddy Sreenivasulu

    2015-03-01

    Full Text Available This paper presents the influence of cutting parameters like cutting speed, feed rate, drill diameter, point angle and clearance angle on the burr size, surface roughness and circularity deviation of Al 6061 during drilling on CNC vertical machining center. A plan of experiments based on Taguchi technique has been used to acquire the data. An orthogonal array, signal to noise (S/N ratio and analysis of variance (ANOVA are employed to investigate machining characteristics of Al 6061 using HSS twist drill bits of variable tool geometry and maintain constant helix angle of 45 degrees. Confirmation tests have been carried out to predict the optimal setting of process parameters to validate the used approach, obtained the values of 0.2618mm, 0.1821mm, 3.7451µm, 0.0676mm for burr height, burr thickness, surface roughness and circularity deviation respectively. Finally, artificial neural network has been applied to compare the predicted values with the experimental values, good agreement was shown between the predictive model results and the experimental measurements. Normal 0 false false false EN-US X-NONE X-NONE

  4. Fabrication of dense α-alumina layer on Ti-6Al-4V alloy hybrid for bearing surfaces of artificial hip joint.

    Science.gov (United States)

    Khanna, Rohit; Kokubo, Tadashi; Matsushita, Tomiharu; Takadama, Hiroaki

    2016-12-01

    Recent advances in hip replacements are focused towards producing reliable bearing surfaces to enhance their longevity. In this perspective, progressive attempts have been made to improve the wear resistance of polyethylene to eliminate osteolysis and mechanical reliability of brittle alumina ceramics, but in vain. It is proposed that both high wear resistance and mechanical reliability can be retained if a thin layer of dense alumina is formed onto high toughness Ti-6Al-4V alloy. For this purpose, we devised a unique methodology in which a layer of Al metal was deposited onto the Ti alloy substrate by cold spraying (CS), followed by a heat treatment to form Al3Ti reaction layer at their interface to improve adhesion and subsequent micro-arc oxidation (MAO) treatment to transform Al to alumina layer. An optimal MAO treatment of cold sprayed Al formed an adherent and dense α-alumina layer with high Vickers hardness matching with that of sintered alumina used as a femoral head. Structure-phase-property relationships in dense α-alumina layer have been revealed and discussed in the light of our research findings. The designed alumina/Ti alloy hybrid might be a potential candidate for reliable bearing surfaces of artificial hip joint. PMID:27612821

  5. Classification of reflected signals from cavitated tooth surfaces using an artificial intelligence technique incorporating a fiber optic displacement sensor

    Science.gov (United States)

    Rahman, Husna Abdul; Harun, Sulaiman Wadi; Arof, Hamzah; Irawati, Ninik; Musirin, Ismail; Ibrahim, Fatimah; Ahmad, Harith

    2014-05-01

    An enhanced dental cavity diameter measurement mechanism using an intensity-modulated fiber optic displacement sensor (FODS) scanning and imaging system, fuzzy logic as well as a single-layer perceptron (SLP) neural network, is presented. The SLP network was employed for the classification of the reflected signals, which were obtained from the surfaces of teeth samples and captured using FODS. Two features were used for the classification of the reflected signals with one of them being the output of a fuzzy logic. The test results showed that the combined fuzzy logic and SLP network methodology contributed to a 100% classification accuracy of the network. The high-classification accuracy significantly demonstrates the suitability of the proposed features and classification using SLP networks for classifying the reflected signals from teeth surfaces, enabling the sensor to accurately measure small diameters of tooth cavity of up to 0.6 mm. The method remains simple enough to allow its easy integration in existing dental restoration support systems.

  6. The effects of an infiltrating resin and a fluorinated foam on incipient enamel demineralization-an in vitro study%两种方法对早期釉质脱矿治疗效果的体外实验研究

    Institute of Scientific and Technical Information of China (English)

    陈静; 马文盛; 王洁; 刘晔; 牛小雷; 温艳丛

    2014-01-01

    AIM:To evaluate the effects of an infiltrating resin and a fluorinated foam on incipient enamel demineralization .METHODS:75 freshly extracted human premolars were made into artificial incipient enamel demi -neralization models .They were randomly divided into 3 groups ( n=25 ) and were treated with deionized water ( group A), fluorinated foam(group B) and infiltrating resin(group C) respectively.Then they were immersed in artificial sa-liva for 8 weeks at 37 ℃.L value of each tooth was measured immediately, 4 weeks and 8 weeks after treatments by a spectrophotometer.Enamel surface was observed under scanning electron microscope (SEM) 4 weeks after treatment. RESULTS:The L value of all teeth decreased after treatment, the degree of △L value was in the following order:C>B>A.The L value was significantly different between groups at 4 and 8 weeks (P<0.05) except between group A and B immediately after treatments .SEM observation showed that the samples in group C had smooth and homogenous enamel surface, while enamel surface was rough and uneven with hollows and mineral deposits in group A and B .CONCLU-SION:Both infiltrating resin and fluorinated foam have remineralizing effects on demineralized enamel surface, but the former is more effective in a short time.%目的:比较渗透性树脂和氟化泡沫对早期釉质脱矿后的治疗效果。方法:用部分饱和酸缓冲脱矿液将75个人离体前磨牙制备成早期釉质脱矿模型后随机分为3组(n=25),分别采用去离子水(A组)、氟化泡沫( B组)、渗透性树脂( C组)处理脱矿釉质表面;然后浸泡于人工唾液中37℃恒温水浴放置8周,治疗前和治疗后即刻、4周、8周各时间点用分光光度比色仪检测每个牙的L值;用扫描电镜观察治疗4周后的表面形态。结果:脱矿釉质经3种方法处理后其L值均较治疗前减小,C组减小的幅度最大,B组次之,A组最小,除治疗后即刻A组与 B

  7. 生物活性玻璃对体外脱矿釉质再矿化的影响%Effect of bioactive glass on demineralization enamel remineralization in vitro

    Institute of Scientific and Technical Information of China (English)

    方谦; 穆玉; 周雪; 瞿亚男; 彭伟

    2016-01-01

    目的:观察生物活性玻璃对早期脱矿釉质再矿化的作用。方法:将40块牛牙釉质块建立人工龋模型后随机分为4组:生物活性玻璃组(用质量分数6%生物活性玻璃进行再矿化处理)、GC护牙素组、NaF组(用质量分数2%NaF进行再矿化处理)和去离子水组。采用pH循环法进行再矿化处理,2次/d,5 min/次,循环15 d。用显微硬度仪测量脱矿前、再矿化前及再矿化后牙釉质表面的显微硬度,荧光显微镜观察早期釉质龋表层下的荧光带厚度,测定脱矿深度。结果:生物活性玻璃组、GC护牙素组、NaF组再矿化后显微硬度均较再矿化前增加,且生物活性玻璃组提高幅度最大(P<0.05)。4组再矿化区荧光带厚度均较脱矿区降低(P<0.05),其中生物活性玻璃组、GC护牙素组、NaF组均大于去离子水组( P<0.05)。结论:质量分数6%生物活性玻璃溶液促进脱矿釉质再矿化的疗效较好。%Aim:To observe the effect of bioactive glass on the remineralization of demineralization enamel .Methods:Forty bovine teeth were subjected to establish demineralization enamel model , and then were allocated into four groups ran-domly(10 in each group) and treated with 6% bioactive glass, casein phosphopeptide amorphous calcium phosphate (CPP-ACP),2%sodium fluoride(NaF) and deionized water,respectively.Then they were subjected to the pH-cycling,two times a day and 5 minutes each time, cycling for 15 days for remineralization.The surface microhardness(SMH)of the enamel before demineralization,before and after remineralization were measured by microhardness detector .Thickness of fluorescence be-neath the surface of early enamel caries in the demineralization area and the remineralization area were detected by fluores -cence microscopy .Results: The SMH after remineralization in bioactive glass , CPP-ACP and NaF groups was higher than those before

  8. Artificial sweeteners

    DEFF Research Database (Denmark)

    Raben, Anne Birgitte; Richelsen, Bjørn

    2012-01-01

    Artificial sweeteners can be a helpful tool to reduce energy intake and body weight and thereby risk for diabetes and cardiovascular diseases (CVD). Considering the prevailing diabesity (obesity and diabetes) epidemic, this can, therefore, be an important alternative to natural, calorie-containin...

  9. Limb reconstruction with decellularized, non-demineralized bone in a young leporine model

    International Nuclear Information System (INIS)

    Limb salvage from a variety of pathological processes in children is often limited by the unavailability of optimal allograft bone, or an appropriate structural bone substitute. In this study, we sought to examine a practical alternative for pediatric limb repair, based on decellularized, non-demineralized bone grafts, and to determine whether controlled recellularization prior to implantation has any impact on outcome. Growing New Zealand rabbits (n = 12) with a complete, critical-size defect on the left tibiofibula were equally divided into two groups. One group received a decellularized, non-demineralized leporine tibiofibula graft. The other group received an equivalent graft seeded with mesenchymal stem cells labeled with green fluorescent protein (GFP), at a fixed density. Animals were euthanized at comparable time points 3–8 weeks post-implantation. Statistical analysis was by the Student t-test and Fisher’s exact test (P < 0.05). There was no significant difference in the rate of non-union between the two groups, including on 3D micro-CT. Incorporated grafts achieved adequate axial bending rigidity, torsional rigidity, union yield and flexural strength, with no significant differences or unequal variances between the groups. Correspondingly, there were no significant differences in extracellular calcium levels, or alkaline phosphatase activity. Histology confirmed the presence of neobone in both groups, with GFP-positive cells in the recellularized grafts. It was shown that osseous grafts derived from decellularized, non-demineralized bone undergo adequate remodeling in vivo after the repair of critical-size limb defects in a growing leporine model, irrespective of subsequent recellularization. This methodology may become a practical alternative for pediatric limb reconstruction. (paper)

  10. Effects of ionizing radiation on proteins in demineralized, lyophilized or frozen human bone

    Energy Technology Data Exchange (ETDEWEB)

    Antebi, Uri; Mathor, Monica B., E-mail: uri@usp.br, E-mail: mathor@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Guimaraes, Rodrigo P., E-mail: clinicaguimaraes@gmail.com [Santa Casa de Sao Paulo (FCM/SCSP), Sao Paulo, SP (Brazil). Faculdade de Ciencias Medicas

    2015-07-01

    The aim is the study of the application of ionizing radiation (gamma and electron) as sterilizing agents at doses of 15 kGy, 25 kGy and 50 kGy, the demineralized bone tissue frozen and freeze-dried for use in transplants. Five human femoral diaphysis of different donors demineralized bone tissues were preserved as lyophilized or frozen at - 80 deg C. The samples were divided into non-irradiated groups (control) and irradiated by gamma rays or electron beam. The bone proteins were extracted and used to determine the concentrations of total protein, BMP 2 and 7. It was observed a decrease in total protein concentrations, and BMP 2 and 7. The decrease in total protein concentrations, as compared to respective control groups was significant in the lyophilized and frozen samples irradiated at a dose of 50 kGy gamma radiation and beam electrons with greater than 30% reduction. The significant decrease in the levels of BMP 2 and 7 were also observed in higher doses and especially by electron beam. The reductions in the concentrations of total protein and osteoinductive proteins (BMP 2 and 7), were related to the radiation dose, i.e., increase with higher doses of ionizing radiation type and the type of preservation of the bones. The largest reductions in concentrations were observed in bone irradiated by electron beam and at a dose of 50 kGy. But this type of radiation and this high dose are not usual practice for the sterilization of bone tissue. Keywords: demineralized bone tissue, ionizing radiation, Tissue Bank, BMP 2, BMP 7, bone proteins. (author)

  11. Carbonization and demineralization of coals: A study by means of FT–IR spectroscopy

    Indian Academy of Sciences (India)

    V Gómez-Serrano; M C Fernández-González; M L Rojas-Cervantes; M F Alexandre-Franco; A Macías-García

    2003-12-01

    Coal basically consists of two parts-a crystalline, inorganic part, and an amorphous, organic part. Based on this, we intended to study the changes that occurred on the composition and on the chemical structure of coals after carbonization at 1000 or 900°C and demineralization treatments with hydrochloric and hydrofluoric acids. For this, four coals of different categories (or levels) were chosen: semianthracite (A–O) and high volatile bituminous coal (B–O), which are high level coals, and lignite (Li–O) and leonardite (Le–O), these being low level coals. The coals were first analysed in terms of their proximate and elemental compositions and then carbonized and demineralized. Also, the starting coals and the prepared samples were examined by infrared spectroscopy. In addition, a study of the optimization of the application of this technique for only A–O was carried out. For A–O and B–O, the spectra recorded intense absorption bands that are ascribable to vibration modes in mineral components as quartz and aluminosilicates, such as kaolinite. For Li–O and Le–O, the spectra displayed some other bands as well, also quite intense, which have been assigned to bond vibrations in functional groups and structures of their organic part. The carbonization of the coals resulted in significant changes in their inorganic part as the content of quartz increased and the content of aluminosilicates decreased. In addition, the thermal decomposition of mineral carbonates occurred. The carbonization greatly affects the organic part of the coals, especially in Li–O and Le–O, as most functional groups and structures are not thermally stable under heating conditions. With regard to demineralization, HF is a more effective agent than HCl, achieving products with higher organic content. The mass losses are higher in Li–O and Le–O than in A–O and B–O. So, the infrared spectroscopy allows the analysis of both inorganic and organic parts of the coals and of

  12. Assessing the environmental impacts of using demineralized coal for electricity generation

    DEFF Research Database (Denmark)

    Ryberg, Morten; Owsianiak, Mikolaj; Laurent, Alexis

    2014-01-01

    The energy sector is the source of two-thirds of global greenhouse-gas emissions, and is the main target ofclimate policies among authorities and governments. The share of fossil coals (hard coal and lignite) in world total net electricity generation is 40% in 2010. Demineralization or ash removal...... in alkaline and acidic solution to dissolve and remove the ash. This process is well-studied on lab scale but has only to a small extent been tried on a full scale. This assessment is conducted as an aid for further developing thetechnology, allowing for early identification of environmental impacts...

  13. Demineralized dentin matrix combined with recombinant human bone morphogenetic protein-2 in rabbit calvarial defects

    OpenAIRE

    Um, In-Woong; Hwang, Suk-Hyun; Kim, Young-Kyun; Kim, Moon-Young; Jun, Sang-Ho; Ryu, Jae-Jun; Jang, Hyon-Seok

    2016-01-01

    Objectives The aim of this study was to compare the osteogenic effects of demineralized dentin matrix (DDM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) in rabbit calvarial defects with DDM and anorganic bovine bone (ABB) combined with rhBMP-2. Materials and Methods Four round defects with 8-mm diameters were created in each rabbit calvaria. Each defect was treated with one of the following: 1) DDM, 2) ABB/rhBMP-2, or 3) DDM/rhBMP-2. The rhBMP-2 was combined with DDM...

  14. Relationships between medication intake, complaints of dry mouth, salivary flow rate and composition, and the rate of tooth demineralization in situ.

    Science.gov (United States)

    Bardow, A; Nyvad, B; Nauntofte, B

    2001-05-01

    The aim of this study was to describe the relationships between the rate of tooth demineralisation and medication intake, subjective feeling of dry mouth, saliva flow, saliva composition and the salivary level of lactobacilli. The study group consisted of 28 subjects that were divided into three groups according to their unstimulated whole saliva flow rate. Group 1 had an unstimulated saliva low rate 0.30 ml/min (n=9). The rate of tooth demineralization was determined as mineral loss assessed by quantitative microradiography of human root surfaces, exposed to the oral environment for 62 days in situ. The unstimulated and stimulated saliva flow rates, pH, bicarbonate, calcium, phosphate, and protein concentrations, as well as the degree of saturation of saliva with hydroxyapatite and the saliva buffer capacity were determined. The results showed that almost all subjects developed demineralization, albeit at highly varying rates. Eighty-five percent of the subjects in group 1, 33% of the subjects in group 2, and 0% of the subjects in group 3 developed mineral loss above the mean mineral loss for all the root surfaces in this experiment. Futhermore, group 1 differed significantly from groups 2 and 3 in having a higher medication intake, a more pronounced feeling of dry mouth, lower stimulated saliva flow rate, lower stimulated bicarbonate concentration, lower unstimulated and stimulated compositional outputs (bicarbonate, calcium, phosphate, and protein), and a higher Lactobacillus level. The best explanatory variable for high mineral loss in this study was a low unstimulated saliva flow rate. In conclusion, our results suggest that an unstimulated salivary flow rate Navazesh et al. (1992), is a better indicator of increased caries risk due to impaired salivation, than the currently accepted definition of hyposalivation (unstimulated saliva flow rate < or =0.10 ml/min), which relates to the function of the salivary glands (Sreebny, 1992).

  15. THE INFLUENCE OF AIR-DRYING ON HYPER-REMINERALIZATION OF DEMINERALIZED DENTIN - A STUDY ON BULK AS WELL AS ON THIN WET SECTION OF BOVINE DENTIN

    NARCIS (Netherlands)

    INABA, D; IIJIMA, Y; TAKAGI, O; RUBEN, J; ARENDS, J

    1995-01-01

    The influence of air-drying on the remineralization of demineralized bovine dentine was examined in wet bulk samples, in dried bulk samples as well as in wet thin sections. Bulk samples of bovine dentine were first demineralized in an acidic gel (pH = 5) at 37 degrees C for 3 weeks. After 24-hour pr

  16. New Generation Dresden NPP Demineralizer Vault Cleanup Project

    International Nuclear Information System (INIS)

    Electro-coagulation (EC) is a technique that facilitates rapid destabilization and flocculation of colloidal suspensions to cause the suspended solids to separate from slurry phase. It is generally accepted that coagulation is brought about primarily by the reduction of the net surface charge to a point where the colloidal particles, previously stabilized by electrostatic repulsion, can approach closely enough for van der Waals forces to hold them together and allow aggregation. In the EC process, the coagulant is generated in situ by electrolytic oxidation of an appropriate anode material (aluminum in this case). In this process, charged ionic species, metals or otherwise, and suspended solids are removed from wastewater by allowing them to interact with an ion having opposite charge, or with floc of metallic hydroxides generated electrochemically within the effluent. Typically, no supplementary organic polymer coagulant addition is required. Thus, electro-coagulation (EC) was found to be an attractive treatment option to rapidly destabilize the colloidal particulate phase, allowing more facile particulate removal by decantation and/or coarse filtration. However, the liquid medium must have some conductivity (> 100 μmho is preferred), in order to allow effective electrical coupling with the EC electrodes. A very small amount of aluminum or sodium sulfate salts can be added to the feed slurry, adjusting the water quality parameters to a conductivity of >100 μmho and a pH value near 6.0-7.0. The EC-treated vault slurry had a pH value near 6.5 (within the pH range for minimal solubility of amphoteric aluminum hydroxide). In contrast to untreated wastewater, the agglomerated particles in the EC-treated aliquot could be filtered relatively rapidly, yielding a clear filtrate, indicating that the flocs that have been formed are now > 20- μm in size, are pumpable (high shear strength), and filterable/dewaterable with ease (low water content). Final waste volumes also

  17. Modeling of biosorption of Cu(II) by alkali-modified spent tea leaves using response surface methodology (RSM) and artificial neural network (ANN)

    Science.gov (United States)

    Ghosh, Arpita; Das, Papita; Sinha, Keka

    2015-06-01

    In the present work, spent tea leaves were modified with Ca(OH)2 and used as a new, non-conventional and low-cost biosorbent for the removal of Cu(II) from aqueous solution. Response surface methodology (RSM) and artificial neural network (ANN) were used to develop predictive models for simulation and optimization of the biosorption process. The influence of process parameters (pH, biosorbent dose and reaction time) on the biosorption efficiency was investigated through a two-level three-factor (23) full factorial central composite design with the help of Design Expert. The same design was also used to obtain a training set for ANN. Finally, both modeling methodologies were statistically compared by the root mean square error and absolute average deviation based on the validation data set. Results suggest that RSM has better prediction performance as compared to ANN. The biosorption followed Langmuir adsorption isotherm and it followed pseudo-second-order kinetic. The optimum removal efficiency of the adsorbent was found as 96.12 %.

  18. Behaviour of palladium(II), platinum(IV), and rhodium(III) in artificial and natural waters: influence of reactor surface and geochemistry on metal recovery.

    Science.gov (United States)

    Cobelo-Garcia, Antonio; Turner, Andrew; Millward, Geoffrey E; Couceiro, Fay

    2007-03-01

    The recovery of dissolved platinum group elements (PGE: Pd(II), Pt(IV) and Rh(III)) added to Milli-Q water, artificial freshwater and seawater and filtered natural waters has been studied, as a function of pH and PGE concentration, in containers of varying synthetic composition. The least adsorptive and/or precipitative loss was obtained for borosilicate glass under most of the conditions employed, whereas the greatest loss was obtained for low-density polyethylene. Of the polymeric materials tested, the adsorptive and/or precipitative loss of PGE was lowest for fluorinated ethylene propylene (Teflon). The loss of Pd(II) in freshwater was significant due to its affinity for surface adsorption and its relatively low solubility. The presence of natural dissolved organic matter increases the recovery of Pd(II) but enhances the loss of Pt(IV). The loss of Rh(III) in seawater was significant and was mainly due to precipitation, whereas Pd(II) recovery was enhanced, compared to freshwater, because of its complexation with chloride. The results have important implications regarding protocols employed for sample preservation and controlled laboratory experiments used in the study of the speciation and biogeochemical behaviour of PGE. PMID:17386666

  19. Artificial neural network assisted kinetic spectrophotometric technique for simultaneous determination of paracetamol and p-aminophenol in pharmaceutical samples using localized surface plasmon resonance band of silver nanoparticles

    Science.gov (United States)

    Khodaveisi, Javad; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Rohani Moghadam, Masoud; Hormozi-Nezhad, Mohammad Reza

    2015-03-01

    Spectrophotometric analysis method based on the combination of the principal component analysis (PCA) with the feed-forward neural network (FFNN) and the radial basis function network (RBFN) was proposed for the simultaneous determination of paracetamol (PAC) and p-aminophenol (PAP). This technique relies on the difference between the kinetic rates of the reactions between analytes and silver nitrate as the oxidizing agent in the presence of polyvinylpyrrolidone (PVP) which is the stabilizer. The reactions are monitored at the analytical wavelength of 420 nm of the localized surface plasmon resonance (LSPR) band of the formed silver nanoparticles (Ag-NPs). Under the optimized conditions, the linear calibration graphs were obtained in the concentration range of 0.122-2.425 μg mL-1 for PAC and 0.021-5.245 μg mL-1 for PAP. The limit of detection in terms of standard approach (LODSA) and upper limit approach (LODULA) were calculated to be 0.027 and 0.032 μg mL-1 for PAC and 0.006 and 0.009 μg mL-1 for PAP. The important parameters were optimized for the artificial neural network (ANN) models. Statistical parameters indicated that the ability of the both methods is comparable. The proposed method was successfully applied to the simultaneous determination of PAC and PAP in pharmaceutical preparations.

  20. Comparison of artificial neural network (ANN) and response surface methodology (RSM) in optimization of the immobilization conditions for lipase from Candida rugosa on Amberjet(®) 4200-Cl.

    Science.gov (United States)

    Fatiha, Benamia; Sameh, Bouchagra; Youcef, Saihi; Zeineddine, Djeghaba; Nacer, Rebbani

    2013-01-01

    Candida rugosa lipase (CRL) is an important industrial enzyme that is successfully utilized in a variety of hydrolysis and esterification reactions. This work describes the optimization of immobilization conditions (enzyme/support ratio, immobilization temperature, and buffer concentration) of CRL on the anionic resin Amberjet® 4200-Cl, using enantioselectivity (E) as the reference parameter. The model reaction used for this purpose is the acylation of (R,S)-1-phenylethanol. Optimal conditions for immobilization have been investigated through a response surface methodology (RSM) and artificial neural network (ANN). The coefficient of determination (R(2)) and the root mean square error (RMSE) values between the calculated and estimated responses were respectively equal to 0.99 and 0.06 for the ANN training set, 0.97 and 0.2 for the ANN testing set, and 0.94 and 0.4 for the RSM training set. Both models provided good quality predictions, yet the ANN showed a clear superiority over RSM for both data fitting and estimation capabilities. PMID:23215653

  1. Modeling and optimization of anaerobic codigestion of potato waste and aquatic weed by response surface methodology and artificial neural network coupled genetic algorithm.

    Science.gov (United States)

    Jacob, Samuel; Banerjee, Rintu

    2016-08-01

    A novel approach to overcome the acidification problem has been attempted in the present study by codigesting industrial potato waste (PW) with Pistia stratiotes (PS, an aquatic weed). The effectiveness of codigestion of the weed and PW was tested in an equal (1:1) proportion by weight with substrate concentration of 5g total solid (TS)/L (2.5gPW+2.5gPS) which resulted in enhancement of methane yield by 76.45% as compared to monodigestion of PW with a positive synergistic effect. Optimization of process parameters was conducted using central composite design (CCD) based response surface methodology (RSM) and artificial neural network (ANN) coupled genetic algorithm (GA) model. Upon comparison of these two optimization techniques, ANN-GA model obtained through feed forward back propagation methodology was found to be efficient and yielded 447.4±21.43LCH4/kgVSfed (0.279gCH4/kgCODvs) which is 6% higher as compared to the CCD-RSM based approach. PMID:27155267

  2. Artificial Intelligence.

    Science.gov (United States)

    Lawrence, David R; Palacios-González, César; Harris, John

    2016-04-01

    It seems natural to think that the same prudential and ethical reasons for mutual respect and tolerance that one has vis-à-vis other human persons would hold toward newly encountered paradigmatic but nonhuman biological persons. One also tends to think that they would have similar reasons for treating we humans as creatures that count morally in our own right. This line of thought transcends biological boundaries-namely, with regard to artificially (super)intelligent persons-but is this a safe assumption? The issue concerns ultimate moral significance: the significance possessed by human persons, persons from other planets, and hypothetical nonorganic persons in the form of artificial intelligence (AI). This article investigates why our possible relations to AI persons could be more complicated than they first might appear, given that they might possess a radically different nature to us, to the point that civilized or peaceful coexistence in a determinate geographical space could be impossible to achieve.

  3. Artificial intelligence

    OpenAIRE

    Duda, Antonín

    2009-01-01

    Abstract : Issue of this work is to acquaint the reader with the history of artificial inteligence, esspecialy branch of chess computing. Main attention is given to progress from fifties to the present. The work also deals with fighting chess programs against each other, and against human opponents. The greatest attention is focused on 1997 and duel Garry Kasparov against chess program Deep Blue. The work is divided into chapters according to chronological order.

  4. Artificial vision.

    Science.gov (United States)

    Zarbin, M; Montemagno, C; Leary, J; Ritch, R

    2011-09-01

    A number treatment options are emerging for patients with retinal degenerative disease, including gene therapy, trophic factor therapy, visual cycle inhibitors (e.g., for patients with Stargardt disease and allied conditions), and cell transplantation. A radically different approach, which will augment but not replace these options, is termed neural prosthetics ("artificial vision"). Although rewiring of inner retinal circuits and inner retinal neuronal degeneration occur in association with photoreceptor degeneration in retinitis pigmentosa (RP), it is possible to create visually useful percepts by stimulating retinal ganglion cells electrically. This fact has lead to the development of techniques to induce photosensitivity in cells that are not light sensitive normally as well as to the development of the bionic retina. Advances in artificial vision continue at a robust pace. These advances are based on the use of molecular engineering and nanotechnology to render cells light-sensitive, to target ion channels to the appropriate cell type (e.g., bipolar cell) and/or cell region (e.g., dendritic tree vs. soma), and on sophisticated image processing algorithms that take advantage of our knowledge of signal processing in the retina. Combined with advances in gene therapy, pathway-based therapy, and cell-based therapy, "artificial vision" technologies create a powerful armamentarium with which ophthalmologists will be able to treat blindness in patients who have a variety of degenerative retinal diseases.

  5. Effect of Solvent Swelling on the reactivity of demineralized Turkish Lignite

    Directory of Open Access Journals (Sweden)

    Murat Sert

    2015-03-01

    Full Text Available In this research, effect of demineralization and solvent swelling on pyrolysis kinetics was investigated. The experiments were carried out to investigate theeffects of solvent swelling with different solvents, such as THF, Pyridine and DMSO after demineralization with HCl, HNO3 and HF successively. To calculate the activation energies of lignite sample during pyrolysis, TGA analyses were performed with raw and swollen samples at 5, 10 and 20° C/min heating rates. Coast-Redfernmodel was used for the determination of kinetic parameters. According to the results, the macromolecular structure of lignite was affected from these hydrogen bonding solvents. So, the activation energies of swollen samples found to be less than the raw lignite sample for all heating rates. The reactivity of lignite samples can be ordered as follows; DMSO swollen sample > Pyridine swollen sample> THF swollen sample. Activation energy of DMSO swollen lignite sample is 10.62 kJ/mole whereas activation energies of pyridine swollen and THF swollen sample are 17.83, 25.76 kJ/mol, respectively at a heating rate of 10° C/min. The results indicated that, solvent swelling has catalytic effect on pyrolysis kinetics.

  6. Genetical stability and osteogenic ability of mesenchimal stem cells on demineralized bone matrices

    Directory of Open Access Journals (Sweden)

    A. Pozzuoli

    2015-03-01

    Full Text Available Aim Tissue engineering is a rapidly expanding field with regard to the use of biomaterials and stem cells in the orthopedic surgery. Many experimental studies have been done to understand the best characteristics of cells, materials and laboratory methods for safe clinical applications. The aim of this study was to compare the ability of 2 different human demineralized bone matrices (DBMs, the one enriched and the other not enriched with hyaluronic acid, to stimulate in vitro the proliferation and the osteogenic differentiation of human adipose-derived stem cells (ADSCs seeded onto an osteoconductive scaffold. Materials and Methods ADSCs were isolated, by enzymatic digestion, from abdominal adipose tissue of 5 patients undergoing cosmetic lipoaspiration surgery. ADSCs were then seeded onto a 3D scaffold in the presence of the two different osteoinductive matrices of human demineralized bone and evaluated for proliferation and osteogenic differentiation. The safety of the methods was verified using array-Comparative Genomic Hybridization (array-CGH. Results ADSCs were able to differentiate in osteogenic sense. Both DBMs showed the ability to induce osteogenic differentiation of the cells. Conclusion array-CGH showed no changes at genome level, thus confirming the safety of materials and methods.

  7. Investigation of hyperelastic models for nonlinear elastic behavior of demineralized and deproteinized bovine cortical femur bone.

    Science.gov (United States)

    Hosseinzadeh, M; Ghoreishi, M; Narooei, K

    2016-06-01

    In this study, the hyperelastic models of demineralized and deproteinized bovine cortical femur bone were investigated and appropriate models were developed. Using uniaxial compression test data, the strain energy versus stretch was calculated and the appropriate hyperelastic strain energy functions were fitted on data in order to calculate the material parameters. To obtain the mechanical behavior in other loading conditions, the hyperelastic strain energy equations were investigated for pure shear and equi-biaxial tension loadings. The results showed the Mooney-Rivlin and Ogden models cannot predict the mechanical response of demineralized and deproteinized bovine cortical femur bone accurately, while the general exponential-exponential and general exponential-power law models have a good agreement with the experimental results. To investigate the sensitivity of the hyperelastic models, a variation of 10% in material parameters was performed and the results indicated an acceptable stability for the general exponential-exponential and general exponential-power law models. Finally, the uniaxial tension and compression of cortical femur bone were studied using the finite element method in VUMAT user subroutine of ABAQUS software and the computed stress-stretch curves were shown a good agreement with the experimental data. PMID:26953961

  8. Enhanced release of bone morphogenetic proteins from demineralized bone matrix by gamma irradiation

    International Nuclear Information System (INIS)

    Gamma irradiation is a useful method for sterilizing demineralized bone matrix (DBM), but its effect on the osteoinductivity of DBM is still controversial. In this study, the osteoinductive activity of gamma-irradiated DBM was examined using a mouse myoblastic cell line (C2C12). DBM was extracted from adult bovine bone and was irradiated at a dose of 25 kGy using a 60cobalt gamma-irradiator. Cell proliferation with DBM was not affected by gamma-irradiation, but alkaline phosphatase and osteocalcin productions were significantly increased in C2C12 cell groups treated with gamma-irradiated DBM. It was reasoned that bone morphogenetic proteins were more efficiently released from gamma-irradiated DBM than from the non-irradiated control. This result suggests the effectiveness of radiation sterilization of bone implants - Highlights: • Demineralized bone matrix (DBM) was gamma-irradiated for sterilization. • Irradiated DBM had higher alkaline phosphatase and osteocalcin production. • It was reasoned the more released bone morphogenetic proteins by irradiation. • This result supports the application of radiation sterilization for bone implants

  9. Different protocols to produce artificial dentine carious lesions in vitro and in situ: hardness and mineral content correlation

    OpenAIRE

    Moron, B M; Comar, L P; Wiegand, A.; Buchalla, W.; Yu, H.; Buzalaf, M.A.R.; Magalhães, A C

    2013-01-01

    This study compared dentine demineralization induced by in vitro and in situ models, and correlated dentine surface hardness (SH), cross-sectional hardness (CSH) and mineral content by transverse microradiography (TMR). Bovine dentine specimens (n = 15/group) were demineralized in vitro with the following: MC gel (6% carboxymethylcellulose gel and 0.1 M lactic acid, pH 5.0, 14 days); buffer I (0.05 M acetic acid solution with calcium, phosphate and fluoride, pH 4.5, 7 days); buffer II (0.05 ...

  10. Comparison of the Effect of Fluoride and Non-fluoride Dentifriceson Enamel Demineralization and Remineralization in Vitro%含氟牙膏对釉质脱矿影响的体外研究

    Institute of Scientific and Technical Information of China (English)

    陈舟; 罗宗莲; 杨松

    2001-01-01

    目的:探讨国内常见市售含氟牙膏对完整釉质及脱矿釉质的作用。方法:测定市售的3种含氟牙膏的氟含量,并选取釉质完好的牛牙及人工龋脱矿的牛牙,用3种含氟牙膏和不含氟牙膏刷洗釉面后,乳酸处理1 min,用原子吸收光谱仪测定溶出的钙量。结果:含氟牙膏组和不含氟牙膏组均能使完整釉质的溶钙量明显降低,与空白对照组相比差异有显著性;含氟牙膏组和不含氟牙膏组均能使人工龋脱矿釉质的溶钙量明显下降,并且两组间有显著性差异。结论:含氟牙膏可以增强完整釉质及人工龋脱矿釉质的抗酸溶钙能力,且效果与其氟浓度相关,氟浓度为52.63 μmol/L时可显著提高牙齿抗酸力。%Objective: The purpose of the experiment is to investigate the effect of fluoride dentifrices in China on the intact and artificial caries-like bovine enamels. Methods: The artificial caries-like lesions were created by dipping the teeth into an acid buffered solution. Both the bovine intact enamels and the artificial caries-like enamels were assigned tooth brushing 20 times every half an hour with 3 kinds of fluoride dentifrices and one kind of non-fluoride dentifrices respectively. The amount of calcium dissolved by lactic acid was determined as the susceptibility of demineralization by atomic adsorption spectrometry (AAS). Results: The group treated with fluoride dentifrice showed significantly less demineralization than the non-fluoride group (P<0.02). The effect of inhibition of acid solubility in artificial caries-like enamel after tooth brushing is significantly greater than that in intact enamel. Conclusion: Fluoride dentifrices in this experiment can prevent both intact enamel and artificial caries-like enamel from acid solubility after tooth brushing, and it seems that the effect of the fluoride dentifrices on the redemineralization is greater than the reduction of enamel solubility.

  11. Terahertz Artificial Dielectric Lens

    Science.gov (United States)

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-03-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  12. Radiolarian artificial neural network based paleo sea surface water temperature and salinity changes during the last glacial cycle in the Timor Sea, Indian Ocean

    Science.gov (United States)

    Gupta, S. M.; Malmgren, B. A.

    2015-12-01

    The western Pacific water enters into the Timor Sea (tropical Indian Ocean) by the thermohaline conveyor belt, and this region is under the influence of the SW monsoon. The higher precipitation during the monsoon rains lower the surface salinity in the north-eastern Indian Ocean towards the Bay of Bengal; whereas, the Arabian Sea remains highly saline due to higher evaporation in the region surrounding Arabian deserts. The salinity contrast in the northern Indian Ocean is very unique, and the radiolarian micro-zooplanktons living in the surface water serve a very good proxy for the monsoonal changes in the surface sea-water temperature (SST) and salinity in the geological past. We studied radiolarian faunal variation in the core MD01-2378, located at ~13oS and ~121oE (1783 m water depth), at the inlet of the thermohaline circulation into the Timor Sea. We applied the modern radiolarian based artificial neural networks (ANNs) (Gupta and Malmgren, 2009) to derive the SST and salinity during August-October for the last 140 ka (the full last glacial cycle). Based on the mean estimates of the 10 ANNs, the root mean square error in prediction (RMSEP) for SST is ~1.4oC with correlation between observed and estimated values r=0.98 (Gupta and Malmgren, 2009). Similarly, the RMSEP is 0.3 psu (r=0.94) for the salinity estimates. We derived paleo-SSTs and salinity values using modern radiolarian ANNs and the fossil radiolarian data generated from the core for the last 140-ka (Fig.1). The age model of the core is based on δ18O benthic oxygen isotope stratigraphy and 21 AMS 14C ages up to ~30-ka (Holbourn et al., 2005). Paleo SST-summer varied between 22-28.5oC, and it is in very good agreement with the δ18O benthic record of Holbourn et al. (2005) defining the Last Glacial Maximum (~24 ka) and the Eemian (~125 ka) stages. The salinity fluctuated between 34-35 psu, and compared well with oxygen isotope record representing the LGM and Eemian periods. We gratefully acknowledge

  13. Socket preservation using demineralized freezed dried bone allograft with and without plasma rich in growth factor: A canine study

    Directory of Open Access Journals (Sweden)

    Ahmad Mogharehabed

    2014-01-01

    Full Text Available Background: The accelerating effect of plasma rich in growth factors (PRGFs in the healing of extraction sockets has been demonstrated by some studies. The aim of the present study was to histologically and histomorphometrically evaluate whether bone formation would increase by the combined use of PRGF and demineralized freeze-dried bone allograft (DFDBA. Materials and Methods: In four female dogs, the distal root of the second, third and fourth lower premolars were extracted bilaterally and the mesial roots were preserved. The extraction sockets were randomly divided into DFDBA + PRGF, DFDBA + saline or control groups. Two dogs were sacrificed after 2 weeks and two dogs were sacrificed after 6 weeks. The extraction sockets were evaluated from both histological and histomorphometrical aspects. The data were analyzed by Mann-Whitney followed by Kruskal-Wallis tests using the Statistical Package for the Social Sciences version 20 (SPSS Inc., Chicago, IL, USA. Significant levels were set at 0.05. Results: The least decrease in socket height was observed in the DFDBA + PRGF group (0.73 ± 0.42 mm. The least decrease in the coronal portion was observed in the DFDBA + PRGF group (1.38 ± 1.35 mm². The least decrease in the middle surface was observed in the DFDBA group (0.61 ± 0.80 mm². The least decrease in the apical portion was observed in the DFDBA group (0.34 ± 0.39 mm². Conclusion: The present study showed better socket preservation subsequent to the application of DFDBA and PRGF combination in comparison with the two other groups. However, the difference was not statistically significant.

  14. EFFECT OF FREQUENT CONSUMPTION OF STARCHY FOOD ITEMS ON ENAMEL AND DENTIN DEMINERALIZATION AND ON PLAQUE PH IN-SITU

    NARCIS (Netherlands)

    LINGSTROM, P; BIRKHED, D; RUBEN, J; ARENDS, J

    1994-01-01

    The aim of this cross-over study was to determine the cariogenic potential of starchy food items as between-meal snacks. This was done by measuring demineralization of human enamel and dentin as well as the pH of dental plaque in situ. Eight volunteers with complete dentures carried two enamel and t

  15. Effect of fluoridated milk on enamel demineralization adjacent to fixed orthodontic appliances

    DEFF Research Database (Denmark)

    Sköld-Larsson, Kerstin; Sollenius, Ola; Karlsson, Lena;

    2012-01-01

    Abstract Objective. To investigate the effect of daily intake of fluoridated milk on enamel demineralization adjacent to fixed orthodontic brackets assessed with quantitative light-induced fluorescence (QLF). Materials and methods. Sixty-four healthy adolescents (13-18 years) undergoing orthodontic...... treatment with fixed appliances were enrolled and randomly allocated to a randomized controlled trial with two parallel groups. The intervention group was instructed to drink one glass of milk (~ 200 ml) supplemented with fluoride (5 ppm) once daily and the subjects of the control group to drink the same...... amount of milk without fluoride. The intervention period was 12 weeks and the end-point was mineral gain or loss in enamel, assessed by QLF on two selected sites from each individual. The attrition rate was 12.5% and 112 sites were included in the final evaluation. Results. There was no statistically...

  16. Minimal invasive surgery for unicameral bone cyst using demineralized bone matrix: a case series

    Directory of Open Access Journals (Sweden)

    Cho Hwan

    2012-07-01

    Full Text Available Abstract Background Various treatments for unicameral bone cyst have been proposed. Recent concern focuses on the effectiveness of closed methods. This study evaluated the effectiveness of demineralized bone matrix as a graft material after intramedullary decompression for the treatment of unicameral bone cysts. Methods Between October 2008 and June 2010, twenty-five patients with a unicameral bone cyst were treated with intramedullary decompression followed by grafting of demineralized bone matrix. There were 21 males and 4 female patients with mean age of 11.1 years (range, 3–19 years. The proximal metaphysis of the humerus was affected in 12 patients, the proximal femur in five, the calcaneum in three, the distal femur in two, the tibia in two, and the radius in one. There were 17 active cysts and 8 latent cysts. Radiologic change was evaluated according to a modified Neer classification. Time to healing was defined as the period required achieving cortical thickening on the anteroposterior and lateral plain radiographs, as well as consolidation of the cyst. The patients were followed up for mean period of 23.9 months (range, 15–36 months. Results Nineteen of 25 cysts had completely consolidated after a single procedure. The mean time to healing was 6.6 months (range, 3–12 months. Four had incomplete healing radiographically but had no clinical symptom with enough cortical thickness to prevent fracture. None of these four cysts needed a second intervention until the last follow-up. Two of 25 patients required a second intervention because of cyst recurrence. All of the two had a radiographical healing of cyst after mean of 10 additional months of follow-up. Conclusions A minimal invasive technique including the injection of DBM could serve as an excellent treatment method for unicameral bone cysts.

  17. Effects of ionizing radiation on proteins in lyophilized or frozen demineralized human bone

    Science.gov (United States)

    Antebi, Uri; Mathor, Monica Beatriz; da Silva, André Ferreira; Guimarães, Rodrigo Pereira; Honda, Emerson Kiyoshi

    2016-01-01

    Objective The aim was to study the effects of application of ionizing radiation (gamma and electrons) as sterilizing agents at doses of 15 kGy, 25 kGy and 50 kGy, on lyophilized or frozen demineralized bone tissue for use in transplants. Methods Five human femoral diaphyses from different donors of musculoskeletal tissue were demineralized and preserved as lyophilized or frozen at −80 °C. The samples were divided into two groups: non-irradiated (control) and irradiated by means of gamma rays or an electron beam. The bone proteins were extracted and used to determine the concentrations of total protein and BMP 2 and 7. Results Decreases in total protein and BMP 2 and 7 concentrations were observed. The decreases in total protein concentrations, in comparison with the respective control groups, were significant in the lyophilized and frozen samples that were irradiated at a dose of 50 kGy of gamma radiation and electron beam, with reductions of more than 30%. Significant decreases in the levels of BMP 2 and 7 were also observed at higher doses and especially through use of the electron beam. Conclusion The reductions in the concentrations of total proteins and osteoinductive proteins (BMP 2 and 7) were related to the radiation dose, i.e. they increased with higher doses of ionizing radiation type and the type of bone preservation. The largest reductions in concentrations were observed in the bones irradiated by means of an electron beam and at a dose of 50 kGy. However, this type of radiation and this high dose are not usual practices for sterilization of bone tissue. PMID:27069893

  18. Novel Dental Cement to Combat Biofilms and Reduce Acids for Orthodontic Applications to Avoid Enamel Demineralization

    Directory of Open Access Journals (Sweden)

    Ning Zhang

    2016-05-01

    Full Text Available Orthodontic treatments often lead to biofilm buildup and white spot lesions due to enamel demineralization. The objectives of this study were to develop a novel bioactive orthodontic cement to prevent white spot lesions, and to determine the effects of cement compositions on biofilm growth and acid production. 2-methacryloyloxyethyl phosphorylcholine (MPC, nanoparticles of silver (NAg, and dimethylaminohexadecyl methacrylate (DMAHDM were incorporated into a resin-modified glass ionomer cement (RMGI. Enamel shear bond strength (SBS was determined. Protein adsorption was determined using a micro bicinchoninic acid method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate metabolic activity, colony-forming units (CFU and lactic acid production. Incorporating 3% of MPC, 1.5% of DMAHDM, and 0.1% of NAg into RMGI, and immersing in distilled water at 37 °C for 30 days, did not decrease the SBS, compared to control (p > 0.1. RMGI with 3% MPC + 1.5% DMAHDM + 0.1% NAg had protein amount that was 1/10 that of control. RMGI with triple agents (MPC + DMAHDM + NAg had much stronger antibacterial property than using a single agent or double agents (p < 0.05. Biofilm CFU on RMGI with triple agents was reduced by more than 3 orders of magnitude, compared to commercial control. Biofilm metabolic activity and acid production were also greatly reduced. In conclusion, adding MPC + DMAHDM + NAg in RMGI substantially inhibited biofilm viability and acid production, without compromising the orthodontic bracket bond strength to enamel. The novel bioactive cement is promising for orthodontic applications to hinder biofilms and plaque buildup and enamel demineralization.

  19. Concentrations and antioxidative activity of anserine and carnosine in poultry meat extracts treated with demineralization and papain.

    Science.gov (United States)

    Huang, S C; Kuo, J C

    2000-10-01

    Anserine and carnosine found in animal skeletal muscle are capable of inhibiting the catalysis of lipid oxidation by heme and non-heme iron. A demineralization technique and a proteolytic enzyme (papain) were used in this research in order to reduce the levels of proxidants while maintaining high levels of anserine and camosine in poultry (chicken, duck and turkey) meat extracts. Undemineralized poultry meat extracts contained larger amounts of anserine, camosine, heme and non-heme iron (p meat extracts. Both undemineralized and demineralized breast meat extracts of chicken, duck and turkey contained higher concentrations of anserine and camosine, but lower amounts of heme and non-heme iron than did thigh meat extracts. In chicken, duck and turkey meat (breast and thigh) extracts (undemineralized and demineralized), the anserine concentrations were greater (p meat extracts was not significantly different (p > 0.05): however, demineralized chicken breast meat extracts showed higher (p meat extracts. The concentrations of anserine, camosine, heme and non-heme iron in chicken breast meat extracts increased (p papain (1%) to the meat mixture before extraction. Heme and non-heme iron in the chicken breast meat extracts increased as the reaction time for papain increased from 30 to 120 min, but the concentrations of anserine and camosine were not significantly affected by the longer reaction time for papain. The hydrogen-donating ability and ferrous chelating ability of demineralized chicken breast meat extracts were not significantly affected by papain. The ratios of carnosine/anserine were very specific in the chicken, duck and turkey meat extracts (breast and thigh); and the turkey meat extracts had lower (p meat extracts. The camosine/anserine ratios of undemineralized and demineralized poultry meat extracts were not significantly different (p > 0.05). This suggests that the carnosine/anserine ratios of undemineralized chicken (0.62 - 0.80), duck (0.75 - 0.77) and

  20. Artificial Economy

    Directory of Open Access Journals (Sweden)

    Alexandru JIVAN

    2011-08-01

    Full Text Available This paper proposes to eliminate, a routine in the economic thinking, claimed to be responsible for the negative essence of economic developments, from the point of view, of the ecological implications (employment in the planetary ecosystem. The methodological foundations start from the natural origins of the functionality of the human economic society according to the originary physiocrat liberalism, and from specific natural characteristics of the humankind. This paper begins with a comment-analysis of the difference between natural and artificial within the economy, and then explains some of the most serious diversions from the natural essence of economic liberalism. It shall be explained the original (heterodox interpretation of the Classical political economy (economics, by making calls to the Romanian economic thinking from aggravating past century. Highlighting the destructive impact of the economy - which, under the invoked doctrines, we call unnatural - allows an intuitive presentation of a logical extension of Marshall's market price, based on previous research. Besides the doctrinal arguments presented, the economic realities inventoried along the way (major deficiencies and effects, determined demonstrate the validity of the hypothesis of the unnatural character and therefore necessarily to be corrected, of the concept and of the mechanisms of the current economy.The results of this paper consist of original heterodox methodspresented, intuitive or developed that can be found conclusively within the key proposals for education and regulation.

  1. Heterotopic Ossification around the Knee after Internal Fixation of a Complex Tibial Plateau Fracture Combined with the Use of Demineralized Bone Matrix (DBM: A Case Report

    Directory of Open Access Journals (Sweden)

    1.\tSjoerd P.F.T. Nota

    2014-10-01

    Full Text Available Demineralized bone matrix has been successfully commercialized as an alternative bone graft material that not only can function as filler but also as an osteoinductive graft. Numerous studies have confirmed its beneficial use in clinical practice. Heterotopic ossification after internal fixation combined with the use of demineralized bone matrix has not been widely reported. In this paper we describe a 39 year old male who sustained a complex articular fracture that developed clinically significant heterotopic ossification after internal fixation with added demineralized bone matrix. Although we cannot be sure that there is a cause-and-effect relation between demineralized bone matrix and the excessive heterotopic ossification seen in our patient, it seems that some caution in using demineralised bone matrix in similar cases is warranted. Also, given the known inter- and intraproduct variability, the risks and benefits of these products should be carefully weighed.

  2. 人纳米脱钙骨基质复合物的理化性质和安全性%Physicochemical property and safety of nanometer human demineralized bone matrix composite

    Institute of Scientific and Technical Information of China (English)

    房雷; 陈雄生; 黄凯; 周盛源; 朱巍; 王辉; 邵将; 贾连顺

    2013-01-01

    matrix in previous experiment, we mixed the recombinant human bone morphogenetic protein-2 together to obtain the new bone graft substitute and to research its physical and chemical properties and biological security. METHODS:The human demineralized bone matrixes were prepared by the method of modified Urist and nano-processed then mixed with the bone morphogenetic protein-2 in specific proportions in order to be lyophilized to complete the fol owing experiments. (1) Pyrogen experiment:the material extracts were injected in the rabbits by ear intravenous. (2) Toxicity experiments:material extracts and saline were separately injected via the tail vein of mice in vivo. (3) Implantation experiments:experimental materials andβ-tricalcium phosphate were implanted into rabbits on both sides of the hindlimb muscle. RESULTS AND CONCLUSION:After lyophilized shaping, the nanometer demineralized bone matrix material had dense surface and it’s pore diameter was 100-400μm. The pore distribution was less uniform and the porosity was of less than 30%. The main elements were carbon, oxygen and nitrogen. Nanometer human demineralized bone matrix with recombinant human bone morphogenetic protein-2 did not have pyrogen effect and the rabbits’ body temperature had no significant fluctuations after injection. The acute systemic toxicity test results showed that the nanometer human demineralized bone matrix with recombinant human bone morphogenetic protein-2 complied with the relevant provisions of the State, without obvious toxic reaction. The inflammatory response of nanometer human demineralized bone matrix with recombinant human bone morphogenetic protein-2 was significantly lighter than the reaction ofβ-tricalcium phosphate. The results showed that the nanometer human demineralized bone matrix with recombinant human bone morphogenetic protein-2 is a nanometer al ogeneic bone graft substitutes with nontoxicity, good biocompatibility, high bioavailability, and less inflammatory

  3. Effect of different prophylaxis methods on sound and demineralized enamel Efeito de diferentes métodos de profilaxia sobre o esmalte hígido e desmineralizado

    Directory of Open Access Journals (Sweden)

    Heitor Marques Honório

    2006-04-01

    Full Text Available Considering the importance of professional plaque control for caries prevention, this study comprised an in vitro evaluation of wear by two prophylaxis methods (sodium bicarbonate jet - Profident and pumice and brush on sound bovine enamel and with artificial carious lesions. Sixty enamel fragments were employed (4x4mm, which were divided into 4 groups: GI - 15 sound blocks treated with pumice and brush; GII - 15 sound blocks treated with Profident; GIII - 15 demineralized blocks treated with pumice and brush, and GIV - 15 demineralized blocks treated with Profident. In the fragments of Groups III and IV, artificial carious lesions were simulated by immersion in 0.05M acetic acid solution 50% saturated with bovine enamel powder at 37ºC for 16h. The specimens were submitted to the prophylactic treatments for 10 seconds. Wear analysis was performed by profilometer and revealed the following results: 0.91µm - GI; 0.42µm - GII; 1.6µm - GIII, and 0.94µm - GIV. The two-way ANOVA and Tukey's test (pTendo em vista a importância do controle profissional da placa na prevenção da cárie, este estudo avaliou in vitro o desgaste de dois métodos de profilaxia (jato de bicarbonato de sódio-Profident e escova de Robinson com pasta de pedra pomes sobre o esmalte bovino hígido e com lesões artificiais de cárie. Foram utilizados 60 fragmentos de esmalte (4 X 4mm, divididos em 4 grupos: GI- 15 blocos hígidos tratados com escova de Robinson e pasta de pedra pomes; GII- 15 blocos hígidos tratados com Profident; GIII- 15 blocos desmineralizados tratados com escova de Robinson e pedra pomes e GIV- 15 blocos desmineralizados tratados com Profident. Nos fragmentos dos grupos III e IV foram simuladas lesões artificiais de cárie através da imersão em solução de ácido acético 0,05M, 50% saturada com pó de esmalte bovino, a 37ºC por 16 h. Os espécimes foram submetidos aos tratamentos profiláticos durante 10 segundos. A análise do desgaste foi

  4. 1H MR spectroscopy of the lumbar spine in bone demineralization of patients suffering from diffuse multiple myeloma or osteoporosis

    International Nuclear Information System (INIS)

    Purpose: To evaluate the role of in vivo 1H MR spectroscopic determination of relaxation times and of fat and water content to differentiate between infiltration of multiple myeloma or osteoporosis in patients with roentgenologic nuclear demineralization of the lumbar spine. Results: There were highly significant differences in T2 values and fat content between patients with osteoporosis and multiple myeloma. T2 values were decreased in osteoporosis (37 ms and 59 ms vs. 44 ms and 70 ms in plasmocytoma) and fat content was decreased in multiple myeloma (20% vs 31% and 34% in volunteers and osteoporosis). Between volunteers and patients with osteoporosis the differences in the T2 of the fat component was significantly different. Conclusions: In our preliminary experience MRS is helpful in the differential diagnosis of bony demineralization. It enables a differentiation between osteoporosis and diffuse multiple myeloma. T2 value measurements may be helpful in the diagnostic trial of osteoporosis. (orig./AJ)

  5. Enamel and dentine demineralization by a combination of starch and sucrose in a biofilm – caries model

    OpenAIRE

    Juliana Nunes BOTELHO; Mario VILLEGAS-SALINAS; Pía TRONCOSO-GAJARDO; Rodrigo Andrés GIACAMAN; Jaime Aparecido CURY

    2016-01-01

    Abstract Sucrose is the most cariogenic dietary carbohydrate and starch is considered non-cariogenic for enamel and moderately cariogenic for dentine. However, the cariogenicity of the combination of starch and sucrose remains unclear. The aim of this study was to evaluate the effect of this combination on Streptococcus mutans biofilm composition and enamel and dentine demineralization. Biofilms of S. mutans UA159 were grown on saliva-coated enamel and dentine slabs in culture medium containi...

  6. Validation of a Cariogenic Biofilm Model to Evaluate the Effect of Fluoride on Enamel and Root Dentine Demineralization

    OpenAIRE

    Fernández, Constanza E.; Tenuta, Livia M. A.; Jaime A. Cury

    2016-01-01

    Due to gingival recession both enamel and root dentine are at risk of developing caries. Both tissues are exposed to a similar environment, however there is not a validated model to evaluate the effect of fluoride on these dental substrates simultaneously. Hence, this study aimed to validate a caries model to evaluate the effect of fluoride to prevent demineralization on enamel and root-dentine. Streptococcus mutans UA159 biofilms were formed on saliva-coated bovine enamel and root dentine sl...

  7. Demineralized Bone Matrix Injection in Consolidation Phase Enhances Bone Regeneration in Distraction Osteogenesis via Endochondral Bone Formation

    OpenAIRE

    Kim, Ji-Beom; Lee, Dong Yeon; Seo, Sang Gyo; Kim, Eo Jin; Kim, Ji Hye; Yoo, Won Joon; Cho, Tae-Joon; Choi, In Ho

    2015-01-01

    Background Distraction osteogenesis (DO) is a promising tool for bone and tissue regeneration. However, prolonged healing time remains a major problem. Various materials including cells, cytokines, and growth factors have been used in an attempt to enhance bone formation. We examined the effect of percutaneous injection of demineralized bone matrix (DBM) during the consolidation phase on bone regeneration after distraction. Methods The immature rabbit tibial DO model (20 mm length-gain) was u...

  8. Studying the processes of sulphates and chlorides extraction from water at low-waste water demineralization technology

    OpenAIRE

    Inna M. Тrus; Iryna M. Маkаrеnko; Тetyana O. Shabliy

    2014-01-01

    To solve the disposal problem of high-salinity liquid wastes resulting from the water demineralization, researched are the processes of chlorides’ and sulphates’ ion-exchange separation with further sulphates (in the form of calcium sulphate) removal from the technological cycle. It is shown that the desulphatized water can be effectively desalinated by reverse osmosis filters, including low-pressure membranes Filmtec TW30-1812-50. The liquid waste obtained in form of concentrates, does cont...

  9. Effect of the coal particle size on pyrolysis and char reactivity for two types of coal and demineralized coal

    Energy Technology Data Exchange (ETDEWEB)

    Wenkui Zhu; Wenli Song; Weigang Lin [Chinese Academy of Sciences, Beijing (China). State Key Laboratory of Multi-phase Complex System

    2008-07-15

    A better understanding of the influence of particle size on pyrolysis and char reactivity is of crucial importance in optimizing the integrated process combining coal topping (coal fast pyrolysis) with char gasification. Different size fractions of two types of coal and demineralized coal were pyrolyzed in a spouted bed. The resulting chars were characterized by X-ray diffraction, and char reactivity was determined in a thermogravimetric analyzer (TGA). Within the range of particle sizes investigated, an increase in particle size results in an increase of char yield, which may be caused by the secondary reactions of volatile matters inside the coal particles. No significant difference in crystallinity was observed for the chars from different size fractions of the parent coals, while more crystallinity was observed for the chars from demineralized coals, which suggests that minerals in the coal play a role in the reduction of char crystallinity during pyrolysis. Char reactivity for raw coals decreased with the increasing of the particle size. For the demineralized coal samples, the change in char reactivity with the increasing of the particle size was reduced. Both the secondary reactions of volatiles and mineral distribution are believed to cause the influence of coal particle size on char reactivity. 19 refs., 7 figs., 3 tabs.

  10. 渗透树脂对人工龋损显微硬度影响的研究%Effect of resin infiltration on microhardness of artificial caries lesions

    Institute of Scientific and Technical Information of China (English)

    刘永红; 邓辉; 唐龙妹; 张志勇

    2015-01-01

    目的 比较渗透树脂、氟保护漆和窝沟封闭剂处理人工龋损即刻和二次脱矿后釉质表面及纵剖面显微硬度的变化,为渗透树脂的临床应用提供依据.方法 选取40颗牛下切牙制备人工龋,按照随机数字表法随机分为A(渗透树脂)、B(氟保护漆)、C(窝沟封闭剂)、D(空白对照)4组,每组10颗牙.垂直于样本牙唇面将其一分为二,一半样本牙测量釉质表面及纵剖面(唇面断缘下40、80及120 μm 3个层面)不同深度的显微硬度值,将另一半样本牙再次置于脱矿液中,二次测量上述测量平面的显微硬度值.使用扫描电镜观察样本牙纵剖面3种材料的渗透情况.结果 4组组内比较均显示釉质表面显微硬度值最高,随着纵剖面深度增加,釉质显微硬度值下降,且在不同深度断面,4组的显微硬度值相比差异均有统计学意义(P<0.05).3种方法处理人工龋损后,初次测量样本牙组间比较,在釉质表面和纵剖面40 μm处A、B、C3组的显微硬度值均显著高于D组(P<0.05);在纵剖面80 μm处,A组显微硬度值[(324± 17) kg/mm2]与C组[(316±20) kg/mm2]间差异无统计学意义,但两组均显著高于D组[(294±23) kg/mm2] (P<0.05),D组与B组[(303±13) kg/mm2]间差异无统计学意义;在纵剖面120 μm处,A组显微硬度值显著高于其他3组(P<0.05).二次脱矿后再次测量样本牙釉质表面的显微硬度值,结果同初次测量;在纵剖面40 μm处的测量结果与初次测量80 μm处相同;在纵剖面80及120 μm处,A组均显著高于其他3组.结论 渗透树脂能有效加强人工龋损釉质表面和不同深度纵剖面的显微硬度.%Objective To compare the changes of enamel surface and cross-sectional microhardness of artificial caries immediately and after the twice demineralization through coating resin infiltration, fluoride varnish and fissure sealant.Methods A total of forty bovine lower incisors enamel samples with artificial caries

  11. Estimation of lesion progress in artificial root caries by swept source optical coherence tomography in comparison to transverse microradiography.

    Science.gov (United States)

    Natsume, Yuko; Nakashima, Syozi; Sadr, Alireza; Shimada, Yasushi; Tagami, Junji; Sumi, Yasunori

    2011-07-01

    This study aimed to investigate whether swept source optical coherence tomography (SS-OCT) could estimate the lesion depth and mineral loss quantitatively without the use of polarization sensitivity, and to examine a relationship between OCT data and transverse microradiography (TMR) lesion parameters. Twenty-four bovine root dentin specimens were allocated to three groups of 4-, 7-, and 14-day demineralization. Cross-sectional images of the specimens before and after the demineralization were captured by OCT at 1319 nm center wavelength. Following the demineralization, these specimens were cut into sections for TMR analysis. Correlations between the OCT data and TMR lesion parameters were examined. TMR images of the specimens showed cavitated lesions (lesion depth or LD(TMR): 200 to 500 μm, ΔZ or mineral loss: 10,000 to 30,000 vol % μm). The OCT images showed "boundaries," suggesting the lesion front. Integrated dB values before and after the demineralization and their difference (R(D), R(S), and ΔR, respectively) were calculated from the lesion surface to the corrected depth of boundary (LD(OCT)). A statistically significant correlation was found between LD(OCT) and LD(TMR) (p < 0.05, r = 0.68). Similarly, statistically significant correlations were found between ΔZ and R(D) or ΔR. The OCT showed a potential for quantitative estimation of lesion depth and mineral loss with cavitated dentin lesions in vitro.

  12. Recent development on surface modification of artificial disc material for wear resistance%人工椎间盘关节材料表面耐磨改性研究进展

    Institute of Scientific and Technical Information of China (English)

    王松; 廖振华; 刘宇宏; 刘伟强

    2013-01-01

    Generally titanium alloy and ultra-high molecular weight polyethylene (UHMWPE) are software materials in artificial disc joint material pairing, so their surface modification is important to improve the wear resistance and long-term stability of the prosthesis. The recent development to improve surface hardness and wear resistance of the titanium alloy by using heat treatment, micro-arc oxidation, surface infiltration elements, plated DLC films, laser surface modification and ion implantation technology are reviewed. Then the research to improve surface hardness and wear resistance of UHMWPE by plating DLC films are introduced. At last, the future trends of the artificial disc prosthesis wear resistance are analyzed.%钛合金和超高分子量聚乙烯(UHMWPE)在人工椎间盘关节材料配对中一般是软体材料,其表面改性对提高假体耐磨性能及长期稳定性有重要意义.主要介绍了采用热处理、微弧氧化、表面渗元素、表面镀DLC膜、激光表面改性、离子注入技术提高钛合金表面硬度和耐磨性的研究进展,以及采用表面镀DLC膜等提高UHMWPE表面硬度和耐磨性的研究现状,展望了人工椎间盘假体耐磨性研究的发展趋势.

  13. Influence of mineral phase in mineralization of a biocomposite containing chitosan, demineralized bone matrix and bone ash—in vitro study

    Indian Academy of Sciences (India)

    Krithiga Gunasekaran; Santhosh Kumar Baskar; Divya Sapphire Mohan; Thotapalli P Sastry

    2014-05-01

    A resorbable composite which acts as a active barrier in guided bone regeneration was fabricated using chitosan, demineralized bone matrix and bone ash. Its potential to form bone like apatite in simulated body fluid was assessed in this study. The mechanical strength of these composites was correlated with bone ash ratios and composites with better tensile strength were studied for their acellular bioactivity by incubating in simulated body fluid for 21 days. Composites without bone ash did not show acellular bioactivity which was confirmed by thermogravimetric analysis. In case of biocomposites with bone ash, there was an increase in residual weight indicating the mineralization of the composite. The composite containing bone ash has shown the peaks related to phosphate vibrations in its Fourier-transform infrared spectrum. Scanning micrographs revealed formation of apatite like crystals on its surface. Ca/P ratio was found to be 1.7 which is nearer to that of natural bone. Thus, prepared composites can be used as resorbable biocomposite in maxillofacial and oral defects.

  14. Optimality in Microwave-Assisted Drying of Aloe Vera (Aloe barbadensis Miller) Gel using Response Surface Methodology and Artificial Neural Network Modeling

    Science.gov (United States)

    Das, Chandan; Das, Arijit; Kumar Golder, Animes

    2016-07-01

    The present work illustrates the Microwave-Assisted Drying (MWAD) characteristic of aloe vera gel combined with process optimization and artificial neural network modeling. The influence of microwave power (160-480 W), gel quantity (4-8 g) and drying time (1-9 min) on the moisture ratio was investigated. The drying of aloe gel exhibited typical diffusion-controlled characteristics with a predominant interaction between input power and drying time. Falling rate period was observed for the entire MWAD of aloe gel. Face-centered Central Composite Design (FCCD) developed a regression model to evaluate their effects on moisture ratio. The optimal MWAD conditions were established as microwave power of 227.9 W, sample amount of 4.47 g and 5.78 min drying time corresponding to the moisture ratio of 0.15. A computer-stimulated Artificial Neural Network (ANN) model was generated for mapping between process variables and the desired response. `Levenberg-Marquardt Back Propagation' algorithm with 3-5-1 architect gave the best prediction, and it showed a clear superiority over FCCD.

  15. Characteristics of surface energy exchange in the artificial shelter forest land of the hinterland of Taklimakan Desert%沙漠腹地人工绿地地表能量交换特征

    Institute of Scientific and Technical Information of China (English)

    严坤; 李生宇; 雷加强; 王海峰; 孙聪; 严风硕; 李春

    2013-01-01

    In order to reveal the energy exchange characters of artificial irrigated shelter forest land near the ground surface in the hinterland of the Taklimakan Desert.The research applied the Eddy Covariance Method to measure sensible heat and latent heat flux on a typical clear day in growing reason.The results showed as follows:(1)Sensible heat flux is a larger proportion of energy and latent heat flux accounts for a small proportion in the desert and artificial sheher forest land.However the latent heat flux in artificial shelter forest land is more than that in desert because of the surface albedo,soil moisture and land cover change after afforesting the shelter-forests.Compared with the desert,the heat flux and latent heat flux peak increase accordingly in artificial irrigated shelter forest land,the peak of latent heat and sensible heat flux are 230.54 W/m2 and 88.5 W/m2 in artificial shelter forest land,thus the desert area is 220 W/m2 and 17.55 W/m2,the surface energy exchange characteristics in the hinterland of the Taklimakan Desert is similar with other arid areas in northwest China.(2)Average Bowen value is 1.63 in artificial irrigated shelter forest land whereas 10.82 in desert on a typical clear day.After afforesting,average Bowen value and Bowen diurnal range is significantly reduced,only occupied 15% of the desert area,the Bowen in artificial irrigated shelter forest land is similar with oasis in the Northwest China.This proves that microclimate had prompted.(3)Meteorological factors and underlying surface influence surface energy exchange in artificial irrigated shelter forest land.The correlation analysis showed that the order of fitness degree between latent heat and sensible heat flux and single environment factor was:net radiation > variety of air temperature > variety of soil temperature > wind velocity > soil temperature.The surface energy exchange is closely related to several environmental factors.The result will show the

  16. First Artificial Knee Osteoarthritis Knee Joint Surface Replacement Treatment Time%膝骨性关节炎初次人工膝关节表面置换的治疗时机

    Institute of Scientific and Technical Information of China (English)

    叶添生; 张寅权; 张平; 李荣荣; 方大标; 王慧慧; 孙洪体

    2015-01-01

    Objective To explore the first artificial knee osteoarthritis knee joint surface replacement treatment time.MethodsAccording to the Kelgren - Lawrence X-ray osteoarthritis classification and grading Outerbridge cartilage injury, using multiple linear regression analysis method in 21 patients (23) of severe knee osteoarthritis patients primary artificial knee arthroplasty, statistical analysis of the independent variable factors and linear dependencerelation between the effect of surgery.ResultsThe incidence of postoperative pain and dysfunction were significantly improved, an average folow-up of 11.2 + / - 1.5 months, according to the HSS score, optimal 16 knees; Good 3 knee; 4 knees. Multiple linear regression equation of hypothesis test of statistical significance.Conclusion Severe knee osteoarthritis and implementation of the first patients without artificial knee joint replacement therapy and artificial knee joint surface displacement can significantly improve curative effect, but the surgery has certain curative effect degrees of risk and unknown factors.%目的:探讨膝骨性关节炎初次人工膝关节表面置换的治疗时机。方法根据Kelgren-Lawrence X线骨关节炎分级和Outerbridge软骨损伤分级,采用多重线性回归分析方法,对21例(23膝)重度膝骨关节炎患者实施初次人工膝关节表面置换术,统计分析自变量因素和手术效果之间的线性依存关系。结果本组病例术后疼痛和功能障碍均改善,平均随访(11.2±1.5)个月,根据HSS评分,优16膝;良3膝;可4膝。多重线性回归方程的假设检验具有统计学意义。结论选择重度膝骨关节炎和非人工膝关节置换治疗无效患者实施初次人工膝关节表面置换能提高疗效,但该手术治疗存在一定程度的风险和未知疗效影响因素。

  17. Trends in Artificial Intelligence.

    Science.gov (United States)

    Hayes, Patrick

    1978-01-01

    Discusses the foundations of artificial intelligence as a science and the types of answers that may be given to the question, "What is intelligence?" The paradigms of artificial intelligence and general systems theory are compared. (Author/VT)

  18. Dental demineralization and caries in patients with head and neck cancer.

    Science.gov (United States)

    Deng, Jie; Jackson, Leanne; Epstein, Joel B; Migliorati, Cesar A; Murphy, Barbara A

    2015-09-01

    Concurrent chemoradiation (CCR) therapy is a standard treatment for patients with locally advanced head and neck cancer (HNC). It is well documented that CCR causes profound acute and late toxicities. Xerostomia (the symptom of dry mouth) and hyposalivation (decreased salivary flow) are among the most common treatment side effects in this cohort of patients during and following treatment. They are the result of radiation-induced damage to the salivary glands. Patients with chronic hyposalivation are at risk for demineralization and dental cavitation (dental caries), often presenting as a severe form of rapidly developing decay that results in loss of dentition. Usual post-radiation oral care which includes the use of fluoride, may decrease, but does not eliminate dental caries associated with radiation-induced hyposalivation. The authors conducted a narrative literature review regarding dental caries in HNC population based on MEDLINE, PubMed, CLNAHL, Cochrane database, EMBASE, and PsycINFO from 1985 to 2014. Primary search terms included head and/or neck cancer, dental caries, dental decay, risk factor, physical symptom, physical sequellea, body image, quality of life, measurement, assessment, cost, prevention, and treatment. The authors also reviewed information from National Institute of Dental and Craniofacial Research (NIDCR), American Dental Association (ADA), and other related healthcare professional association web sites. This literature review focuses on critical issues related to dental caries in patients with HNC: potential mechanisms and contributing factors, clinical assessment, physical sequellea, negative impact on body image and quality of life, potential preventative strategies, and recommendations for practice and research in this area. PMID:26198979

  19. Osseous healing with a composite of allograft and demineralized bone matrix: adverse effects of smoking.

    Science.gov (United States)

    Ziran, Bruce H; Hendi, Pooneh; Smith, Wade R; Westerheide, Kenneth; Agudelo, Juan F

    2007-04-01

    We report on our use of a composite graft of lyophilized cancellous allogenic chips and demineralized bone matrix (DBM; Grafton; Osteotech, Eatontown, NJ) to manage traumatic osseous defects and nonunions. Data were prospectively collected from all patients who received this composite bone graft between 1996 and 2000. Only acute fractures with bone loss resulting in a uncontained defect and atrophic non-unions were included in the present study. Demographic data and complications related to composite use, tobacco use, and other comorbidities that could affect healing were evaluated. One hundred seven patients (112 bone graft sites) were followed up for a mean of 32 months (range, 12-60 months). Graft sites included the forearm, femur and tibia. Of the 112 patients, there were 56 smokers (25 non-unions and 31 fractures) and 56 non-smokers (28 fractures and 28 non-unions). Healing occured in 38/56 smokers compared with 49/56 non-smokers. In failed cases, smoking was characteristic in 7/9 non-unions and 11/16 fractures. There were 26 acute uncontained injuries, 29 acute contained defects, and 67 nonunions. Grafting sites were radius/ulna (13 cases), humerus (17), femur (31), and tibia/fibula (51). Significant comorbidities were diabetes mellitus (4 cases), fungal osteomyelitis (1), and pulmonary alveolar proteinosis (1). Eight (73%) of the 11 patients with graft failure had a significant smoking history. This composite graft is an option for managing osseous defects and nonunions traditionally treated with autologous bone grafting but should be used with caution when treating patients who are smokers. PMID:17515188

  20. Cartilage tissue engineering of nasal septal chondrocyte-macroaggregates in human demineralized bone matrix.

    Science.gov (United States)

    Liese, Juliane; Marzahn, Ulrike; El Sayed, Karym; Pruss, Axel; Haisch, Andreas; Stoelzel, Katharina

    2013-06-01

    Tissue Engineering is an important method for generating cartilage tissue with isolated autologous cells and the support of biomaterials. In contrast to various gel-like biomaterials, human demineralized bone matrix (DBM) guarantees some biomechanical stability for an application in biomechanically loaded regions. The present study combined for the first time the method of seeding chondrocyte-macroaggregates in DBM for the purpose of cartilage tissue engineering. After isolating human nasal chondrocytes and creating a three-dimensional macroaggregate arrangement, the DBM was cultivated in vitro with the macroaggregates. The interaction of the cells within the DBM was analyzed with respect to cell differentiation and the inhibitory effects of chondrocyte proliferation. In contrast to chondrocyte-macroaggregates in the cell-DBM constructs, morphologically modified cells expressing type I collagen dominated. The redifferentiation of chondrocytes, characterized by the expression of type II collagen, was only found in low amounts in the cell-DBM constructs. Furthermore, caspase 3, a marker for apoptosis, was detected in the chondrocyte-DBM constructs. In another experimental setting, the vitality of chondrocytes as related to culture time and the amount of DBM was analyzed with the BrdU assay. Higher amounts of DBM tended to result in significantly higher proliferation rates of the cells within the first 48 h. After 96 h, the vitality decreased in a dose-dependent fashion. In conclusion, this study provides the proof of concept of chondrocyte-macroaggregates with DBM as an interesting method for the tissue engineering of cartilage. The as-yet insufficient redifferentiation of the chondrocytes and the sporadic initiation of apoptosis will require further investigations.

  1. Investigation of ethanol infiltration into demineralized dentin collagen fibrils using molecular dynamics simulations.

    Science.gov (United States)

    Jee, Sang Eun; Zhou, Jienfeng; Tan, Jianquo; Breschi, Lorenzo; Tay, Franklin R; Grégoire, Geneviève; Pashley, David H; Jang, Seung Soon

    2016-05-01

    The purpose of this study is to investigate the interaction of neat ethanol with bound and non-bound water in completely demineralized dentin that is fully hydrated, using molecular dynamics (MD) simulation method. The key to creating ideal resin-dentin bonds is the removal of residual free water layers and its replacement by ethanol solvent in which resin monomers are soluble, using the ethanol wet-bonding technique. The test null hypotheses were that ethanol cannot remove any collagen-bound water, and that ethanol cannot infiltrate into the spacing between collagen triple helix due to narrow interlayer spacing. Collagen fibrillar structures of overlap and gap regions were constructed by aligning the collagen triple helix of infinite length in hexagonal packing. Three layers of the water molecules were specified as the layers of 0.15-0.22nm, 0.22-0.43nm and 0.43-0.63nm from collagen atoms by investigating the water distribution surrounding collagen molecules. Our simulation results show that ethanol molecules infiltrated into the intermolecular spacing in the gap region, which increased due to the lateral shrinkage of the collagen structures in contact with ethanol solution, while there was no ethanol infiltration observed in the overlap region. Infiltrated ethanol molecules in the gap region removed residual water molecules via modifying mostly the third water layer (50% decrease), which would be considered as a loosely-bound water layer. The first and second hydration layers, which would be considered as tightly bound water layers, were not removed by the ethanol molecules, thus maintaining the helical structures of the collagen molecules. PMID:26969524

  2. Characterization of lignocellulosic biomass thermal degradation and physiochemical structure: Effects of demineralization by diverse acid solutions

    International Nuclear Information System (INIS)

    Highlights: • HF showed interesting results on EFB (empty fruit bunches) and PMF (palm mesocarp fibre) deashing. • HCl indicated maximum ash removal from PKS (palm kernel shell). • Significant pyrolysis reactions took place at ∼250 °C to ∼400 °C. • Inorganics played a considerable catalytic role during the biomasses pyrolysis. • Acid pretreatment introduced some impacts on the biomasses structure. - Abstract: To eliminate the negative impacts of inorganic constituents during biomass thermochemical processes, leaching method by different diluted acid solutions was chosen. The different palm oil biomass samples (palm kernel shell (PKS), empty fruit bunches (EFB) and palm mesocarp fiber (PMF)) were pretreated by various diluted acid solutions (H2SO4, HClO4, HF, HNO3, HCl). Acids with the highest degrees of demineralization were selected to investigate the dematerialization impacts on the biomass thermal characteristics and physiochemical structure. Thermogravimetric analysis coupled with mass spectroscopy (TGA-MS) and Fourier transform infrared spectroscopy (TGA-FTIR) were employed to examine the biomass thermal degradation. TGA and DTG (Derivative thermogravimetry) indicated that the maximum degradation temperatures increased after acid pretreatment due to the minerals catalytic effects. The main permanent evolved gases comprising H2, CO2, CO were detected online during analysis. The major permanent gases produced at the temperature range of 250–750 °C were attributed to the condensable vapors cracking and probably some secondary reactions. The physiochemical structure change of the acid-treated biomass samples was examined by using Brunauer Emmett Teller (BET) method, Scanning Electron Microscope (SEM) and FTIR. The pyrolysis kinetics of the different palm oil biomasses were investigated using first order reaction model

  3. Laser and caries diagnosis: the state of the art and evaluation in vitro of the differences of the fluorescence between sound, carious and demineralized enamel

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the methods for establishing dental caries diagnosis that make use of Laser light as source of illumination, establishing the 'state of the art'. Experimental observation of the differences among fluorescence of sound, demineralized and carious enamel by visible luminescent spectroscopy was also done. Six human teeth, extracted for clinical reasons were studied, and the results showed that the spectrum of carious enamel is different from the sound and demineralized ones. The differences are more evident relative to sond enamel and carious enamel, the same occurring between demineralized and carious enamel. The review of the literature aimed to make comparative considerations between QLF, LF and DELF; their effectiveness relative to traditional methods such as visual, visual with probe, radiography. It was verified that DELF was more sensitive, but could not discriminate between different degrees of mineral loss. QLF, compared to DIAGNOdent has the same sensitivity, but it is better for scientific purposes. The experimental part of the present study used on argon ion Laser to illuminated the teeth and signs of emission of fluorescence were captured by a PMT and then analyzed by a computer system with EG and G software. The results showed that the spectrum of carious enamel is different from the sound and demineralized. The differences are more evident in relation to sound and carious enamel, the same occurs between demineralized and carious enamel. (author)

  4. Artificial Inteligence and Law

    OpenAIRE

    Fuková, Kateřina

    2012-01-01

    Submitted diploma work Artificial Intelligence and Law deals with the rule of law and its position in the process of new advanced technologies in computer cybernetics and further scientific disciplines related with artificial intelligence and its creation. The first part of the work introduces the history of the first imagines about artificial intelligence and concerns with its birth. This chapter presents main theoretical knowledge and hypotheses defined artificial intelligence and progre...

  5. Effects of low-level laser therapy on orthodontic tooth movement and root resorption after artificial socket preservation

    Directory of Open Access Journals (Sweden)

    Massoud Seifi

    2014-01-01

    Full Text Available Background: Low- level laser therapy has been used to stimulate the orthodontic tooth movements (OTM previously. Furthermore, in the orthodontic treatments accompanying tooth extractions, the adjacent teeth move towards the extraction sites and close the space in some cases. Then, the adjacent tooth movements must be prevented in the treatments requiring space. Laser stimulates and at some doses decelerates tooth movement; it also improves healing process and enhances osteogenesis. Hence, it can prevent movement by osteogenesis adjacent to the tooth. The present study investigated the effects of low-level laser therapy on the OTM and root resorption following artificial socket preservation. Materials and Methods: In this experimental animal trial, 16 male albino rabbits were selected with similar characteristics and randomly divided in two groups. Under general anesthesia, an artificial socket, 8 mm in height, was created in the mesial aspect of the first premolars of the rabbits and filled with demineralized freeze dried bone allograft (DFDBA. The first premolars were connected to the incisors using nickel titanium coil springs. In experimental group, gallium-aluminum-arsenide (GaAlAs laser was irritated mesial to first premolar where artificial socket was created continuously (808 nm. The cycle was 10 days irritation, 14 days rest, 10 days irritation, 14 days rest (Biostimulation mode. Control group was not laser irradiated. All animals were sacrificed after 48 days and the distance between the distal aspect of the first premolars, and the mesial surface of the second premolars was measured with leaf gauge. The specimens underwent histological assessments. Integrity of root and its resorption was observed under microscope calibration. The size of resorption lacunae was calculated in mm 2 . Normality of data was proved according to Kolmogorov-Smirnov analysis, and Student′s t-test was done. P value less than 0.05 was considered as significant

  6. Methods for demonstration of enzyme activity in muscle fibres at the muscle/bone interface in demineralized tissue

    DEFF Research Database (Denmark)

    Kirkeby, S; Vilmann, H

    1981-01-01

    A method for demonstration of activity for ATPase and various oxidative enzymes (succinic dehydrogenase, alpha-glycerophosphate dehydrogenase, and lactic dehydrogenase) in muscle/bone sections of fixed and demineralized tissue has been developed. It was found that it is possible to preserve...... considerable amounts of the above mentioned enzymes in the muscle fibres at the muscle/bone interfaces. The best results were obtained after 20 min fixation, and 2-3 weeks of storage in MgNa2EDTA containing media. As the same technique previously has been used to describe patterns of resorption and deposition...

  7. Tadpole-like artificial micromotor

    Science.gov (United States)

    Liu, Limei; Liu, Mei; Su, Yajun; Dong, Yonggang; Zhou, Wei; Zhang, Lina; Zhang, Hui; Dong, Bin; Chi, Lifeng

    2015-01-01

    We describe a polymer-based artificial tadpole-like micromotor, which is fabricated through the electrospinning technique. By incorporating functional materials onto its surface or within its body, the resulting tadpole-like micromotor can not only move autonomously in an aqueous solution with a flexible tail, but also exhibit thermo- and magnetic responsive properties.We describe a polymer-based artificial tadpole-like micromotor, which is fabricated through the electrospinning technique. By incorporating functional materials onto its surface or within its body, the resulting tadpole-like micromotor can not only move autonomously in an aqueous solution with a flexible tail, but also exhibit thermo- and magnetic responsive properties. Electronic supplementary information (ESI) available: Experimental section, Fig. S1-S3 and Video S1-S4. See DOI: 10.1039/c4nr06621a

  8. 电渗析在葡萄糖浆脱盐中的应用%Application of Electrodialysis on Demineralization of Glucose Syrup

    Institute of Scientific and Technical Information of China (English)

    武睿; 于秋生; 陈正行; 郭贯新

    2012-01-01

    电渗析技术应用于葡萄糖浆的脱盐效果显著。研究表明,脱盐最佳条件为:操作电压30V,糖浆流量25L/h,糖浆浓度30%;该条件下,糖浆脱盐率94.69%,糖浆得率77.84%。%Electrodialysis (ED) demineralization of glucose syrup was applied in this research. The results showed that electrodialysis was feasible for glucose syrup demineralization. The optimal operating parameters under experimental working condition were: 30 v applied voltage, 25 L/h flow rate and 30% syrup concentration. After the treatment with these operating parameters, the demineralization ratio was reached to 94.69% and the sugar component retention was 77.84%.

  9. Efficacy of gaseous chlorine dioxide on inactivation of Escherichia coli O157:H7 on surfaces of artificially inoculated fresh-cut Romaine lettuce leaves

    Science.gov (United States)

    Efficacy of antimicrobial agents in inactivating pathogenic microorganisms on fresh and fresh-cut produce surfaces in limited by the accessibility of such agents to the produce surfaces where the microorganisms are residing. Other factors contribute to this problem include biofilm formation by the m...

  10. Quartz crystal microbalance-with dissipation monitoring (QCM-D) for real time measurements of blood coagulation density and immune complement activation on artificial surfaces.

    Science.gov (United States)

    Andersson, Marcus; Andersson, Jonas; Sellborn, Anders; Berglin, Mattias; Nilsson, Bo; Elwing, Hans

    2005-07-15

    A recently developed variant of quartz crystal microbalance (QCM) called QCM-with dissipation monitoring (QCM-D) allows simultaneous and simple measurements of changes in adsorbed mass as well as the viscoelastic property (D-factor) of deposited protein layers on the sensor surface. We have taken the QCM-D technology a step further and demonstrated its advantages in the study of protein assembly as a consequence of surface induced immune complement activation, or contact activated blood coagulation. In the present study we have continued our QCM-D investigations of surface assembly of fibrin clot formation and complement activation and incubated differently modified quartz sensor surfaces in blood plasma and sera. Polymer surfaces used were spin-coated polyethylene, poly(ethylene terephtalate), poly(methylmetacrylate) and poly(dimethylsiloxane). Also used were sputtered titanium and heparin grafted surfaces. In this investigation we found that we could describe the surface induced coagulation with four independent parameters: (1) Time of onset of coagulation, (2) fibrin deposition rate, (3) total frequency shift at stable plateau, and (4) fibrin clot density. The most important finding was that the blood plasma clot density can be assessed with the use of D determinations and that the clot density varied significantly with the chemical composition of the surface. However, the D-factor did not give any new analytical information about the possible complement activation mechanisms. Nevertheless, the QCM-D was found to be a reliable tool for the analysis of surface induced complement activation. We also compared the QCM-D technique with traditional enzyme immuno assay (EIA) measurements of soluble products from the surface activation of the complement and coagulation systems. We found that the results from EIA and QCM-D measurements corresponded well for the complement activation but not for the coagulation, probably due to the biological complexity of the coagulation

  11. Natural water purification and water management by artificial groundwater recharge

    OpenAIRE

    Balke, Klaus-Dieter; Zhu, Yan

    2008-01-01

    Worldwide, several regions suffer from water scarcity and contamination. The infiltration and subsurface storage of rain and river water can reduce water stress. Artificial groundwater recharge, possibly combined with bank filtration, plant purification and/or the use of subsurface dams and artificial aquifers, is especially advantageous in areas where layers of gravel and sand exist below the earth’s surface. Artificial infiltration of surface water into the uppermost aquifer has qualitative...

  12. Autologous bone graft versus demineralized bone matrix in internal fixation of ununited long bones

    Directory of Open Access Journals (Sweden)

    Rubenbauer Bianka

    2009-12-01

    Full Text Available Abstract Background Non-unions are severe complications in orthopaedic trauma care and occur in 10% of all fractures. The golden standard for the treatment of ununited fractures includes open reduction and internal fixation (ORIF as well as augmentation with autologous-bone-grafting. However, there is morbidity associated with the bone-graft donor site and some patients offer limited quantity or quality of autologous-bone graft material. Since allogene bone-grafts are introduced on the market, this comparative study aims to evaluate healing characteristics of ununited bones treated with ORIF combined with either iliac-crest-autologous-bone-grafting (ICABG or demineralized-bone-matrix (DBM. Methods and results From 2000 to 2006 out of sixty-two consecutive patients with non-unions presenting at our Level I Trauma Center, twenty patients had ununited diaphyseal fractures of long bones and were treated by ORIF combined either by ICABG- (n = 10 or DBM-augmentation (n = 10. At the time of index-operation, patients of the DBM-group had a higher level of comorbidity (ASA-value: p = 0.014. Mean duration of follow-up was 56.6 months (ICABG-group and 41.2 months (DBM-group. All patients were clinically and radiographically assessed and adverse effects related to bone grafting were documented. The results showed that two non-unions augmented with ICABG failed osseous healing (20% whereas all non-unions grafted by DBM showed successful consolidation during the first year after the index operation (p = 0.146. No early complications were documented in both groups but two patients of the ICABG-group suffered long-term problems at the donor site (20% (p = 0.146. Pain intensity were comparable in both groups (p = 0.326. However, patients treated with DBM were more satisfied with the surgical procedure (p = 0.031. Conclusion With the use of DBM, the costs for augmentation of the non-union-site are more expensive compared to ICABG (calculated difference: 160

  13. Trace determination of safranin O dye using ultrasound assisted dispersive solid-phase micro extraction: Artificial neural network-genetic algorithm and response surface methodology.

    Science.gov (United States)

    Dil, Ebrahim Alipanahpour; Ghaedi, Mehrorang; Asfaram, Arash; Mehrabi, Fatemeh; Bazrafshan, Ali Akbar; Ghaedi, Abdol Mohammad

    2016-11-01

    In this study, ultrasound assisted dispersive solid-phase micro extraction combined with spectrophotometry (USA-DSPME-UV) method based on activated carbon modified with Fe2O3 nanoparticles (Fe2O3-NPs-AC) was developed for pre-concentration and determination of safranin O (SO). It is known that the efficiency of USA-DSPME-UV method may be affected by pH, amount of adsorbent, ultrasound time and eluent volume and the extent and magnitude of their contribution on response (in term of main and interaction part) was studied by using central composite design (CCD) and artificial neural network-genetic algorithms (ANN-GA). Accordingly by adjustment of experimental conditions suggested by ANN-GA at pH 6.5, 1.1mg of adsorbent, 10min ultrasound and 150μL of eluent volume led to achievement of best operation performance like low LOD (6.3ngmL(-1)) and LOQ (17.5ngmL(-1)) in the range of 25-3500ngmL(-1). In following stage, the SO content in real water and wastewater samples with recoveries between 93.27-99.41% with RSD lower than 3% was successfully determined. PMID:27245964

  14. Clinical e radiographic sucess of indirect pulp capping with partial excavation of demineralization dentin in primary posterior teeth

    Directory of Open Access Journals (Sweden)

    Roberta Francisca Martins de Castro

    2009-10-01

    Full Text Available Objective: To assess the outcome of the indirect pulp capping technique after incomplete excavation of the demineralized dentin in primary molars of patients treated in the period from 2004 to 2006.Methods: Sample consisted of 81 teeth of 36 patients aged from 1-to-8 year-old. Clinical and radiographic inclusion criteria, as well as criteria of the success of the evaluated treatments were established.Results: There were four (4.9% failures and 77 (95.1% successful treatments. Treatment failure occurred in three girls and in one boy, and no statistically significant difference (p=0.341 was found. Twenty three teeth were treated with resin-modified glass-ionomer cement and 58 with composite resin, of which 22 and 55, respectively, showed successful results. There was no statistically significant difference between restorative materials used (p=0.877. As regards the studied age group, patients aged from 1 to 4 years showed a significantly lower success rate when compared with 5-8 year-old children (p = 0.0428. Conclusion: The results suggest that the indirect pulp capping technique after incomplete excavation of demineralized dentin is a reliable technique to be adopted in deep lesions of primary teeth.

  15. CO2 Laser and Topical Fluoride Therapy in the Control of Caries Lesions on Demineralized Primary Enamel

    Directory of Open Access Journals (Sweden)

    R. A. Valério

    2015-01-01

    Full Text Available This study evaluated the effect of CO2 laser irradiation and topical fluoride therapy in the control of caries progression on primary teeth enamel. 30 fragments (3×3×2 mm from primary canines were submitted to an initial cariogenic challenge that consisted of immersion on demineralizing solution for 3 hours and remineralizing solution for 21 hours for 5 days. Fragments were randomly assigned into three groups (n=10: L: CO2 laser (λ=10.6 μm, APF: 1.23% acidulated phosphate fluoride, and C: no treatment (control. CO2 laser was applied with 0.5 W power and 0.44 J/cm2 energy density. Fluoride application was performed with 0.1 g for 1 minute. Cariogenic challenge was conducted for 5 days following protocol previously described. Subsurface Knoop microhardness was measured at 30 μm from the edge. Obtained data were subjected to analysis the variance (ANOVA and Duncan test with significance of 5%. It was found that the L group showed greater control of deciduous enamel demineralization and were similar to those of APF group, while being statistically different from C group (P≤0.05 that showed the lowest microhardness values. It was concluded that CO2 laser can be an additional resource in caries control progression on primary teeth enamel.

  16. Assessment of enamel demineralization using conventional, digital, and digitized radiography Avaliação da desmineralização do esmalte por meio de radiografias convencional, digital e digitalizada

    Directory of Open Access Journals (Sweden)

    Rívea Inês Ferreira

    2006-04-01

    Full Text Available This experimental research aimed at evaluating the accuracy of enamel demineralization detection using conventional, digital, and digitized radiographs, as well as to compare radiographs and logarithmically contrast-enhanced subtraction images. Enamel subsurface demineralization was induced on one of the approximal surfaces of 49 sound third molars. Standardized radiographs of the teeth were taken prior to and after the demineralization phase with three digital systems - CygnusRay MPS®, DenOptix® and DIGORA® - and InSight® film. Three radiologists interpreted the pairs of conventional, digital, and digitized radiographs in two different occasions. Logarithmically contrast-enhanced subtraction images were examined by a fourth radiologist only once. Radiographic diagnosis was validated by cross-sectional microhardness profiling in the test areas of the approximal surfaces. Accuracy was estimated by Receiver Operating Characteristic (ROC analysis. Chi-square test, at a significance level of 5%, was used to compare the areas under the ROC curves (Az calculated for the different imaging modalities. Concerning the radiographs, the DenOptix® system (Az = 0.91 and conventional radiographs (Az = 0.90 presented the highest accuracy values compared with the other three radiographic modalities. However, logarithmically contrast-enhanced subtraction images (Az = 0.98 were significantly more accurate than conventional, digital, and digitized radiographs (p = 0.0000. It can be concluded that the DenOptix® system and conventional radiographs provide better performance for diagnosing enamel subsurface demineralization. Logarithmic subtraction significantly improves radiographic detection.O objetivo desta pesquisa experimental foi investigar a acurácia da detecção de desmineralizações em esmalte por meio de radiografias convencionais, digitais e digitalizadas, e compará-las às imagens por subtração logarítmica. Foram induzidas desmineraliza

  17. Anticipatory Artificial Autopoiesis

    OpenAIRE

    DuBois, Daniel; Holmberg, Stig C.

    2010-01-01

    In examining relationships between autopoiesis and anticipation in artificial life (Alife) systems it is demonstrated that anticipation may increase efficiency and viability in artificial autopoietic living systems. This paper, firstly, gives a review of the Varela et al [1974] automata algorithm of an autopoietic living cell. Some problems in this algorithm must be corrected. Secondly, a new and original anticipatory artificial autopoiesis algorithm for automata is presented. ...

  18. Inteligencia artificial en vehiculo

    OpenAIRE

    Amador Díaz, Pedro

    2012-01-01

    Desarrollo de un robot seguidor de líneas, en el que se implementan diversas soluciones de las áreas de sistemas embebidos e inteligencia artificial. Desenvolupament d'un robot seguidor de línies, en el qual s'implementen diverses solucions de les àrees de sistemes encastats i intel·ligència artificial. Follower robot development of lines, in which various solutions are implemented in the areas of artificial intelligence embedded systems.

  19. Artificial cognition architectures

    CERN Document Server

    Crowder, James A; Friess, Shelli A

    2013-01-01

    The goal of this book is to establish the foundation, principles, theory, and concepts that are the backbone of real, autonomous Artificial Intelligence. Presented here are some basic human intelligence concepts framed for Artificial Intelligence systems. These include concepts like Metacognition and Metamemory, along with architectural constructs for Artificial Intelligence versions of human brain functions like the prefrontal cortex. Also presented are possible hardware and software architectures that lend themselves to learning, reasoning, and self-evolution

  20. Effect of consumption of dairy products with probiotic bacteria on biofilm formation on silicone rubber implant surfaces in an artificial throat

    NARCIS (Netherlands)

    Van der Mei, HC; Van de Belt-Gritter, B; van Weissenbruch, R; Dijk, F; Albers, FWJ; Busscher, HJ

    1999-01-01

    Indwelling voice prostheses are most often made of silicone rubber. However, the silicone rubber surface attracts large quantities of yeasts and bacteria and their colonization on the valve side of voice prostheses leads to frequent malfunctioning Indwelling voice prostheses are therefore usually re

  1. Potential of centrifugal seeding method in improving cells distribution and proliferation on demineralized cancellous bone scaffolds for tissue-engineered meniscus.

    Science.gov (United States)

    Zhang, Zheng-Zheng; Jiang, Dong; Wang, Shao-Jie; Qi, Yan-Song; Zhang, Ji-Ying; Yu, Jia-Kuo

    2015-07-22

    Tissue-engineered meniscus offers a possible solution to the regeneration and replacement problem of meniscectomy. However, the nonuniform distribution and declined proliferation of seeded cells on scaffolds hinder the application of tissue-engineered meniscus as a new generation of meniscus graft. This study systematically investigated the performances of different seeding techniques by using the demineralized cancellous bone (DCB) as the scaffold. Static seeding, injection seeding, centrifugal seeding, and vacuum seeding methods were used to seed the meniscal fibrochondrocytes (MFCs) and mesenchymal stem cells (MSCs) to scaffolds. Cell-binding efficiency, survival rate, distribution ability, and long-term proliferation effects on scaffolds were quantitatively evaluated. Cell adhesion was compared via cell-binding kinetics. Cell viability and morphology were assessed by using fluorescence staining. Combined with the reconstructed three-dimensional image, the distribution of seeded cells was investigated. The Cell Counting Kit-8 assay and DNA assay were employed to assess cell proliferation. Cell-binding kinetics and cell survival of the MFCs were improved via centrifugal seeding compared to injection or vacuum seeding methods. Seeded MFCs by centrifugation showed a more homogeneous distribution throughout the scaffold than cells seeded by other methods. Moreover, the penetration depth in the scaffold of seeded MFCs by centrifugation was 300-500 μm, much higher than the value of 100-300 μm by the surface static and injection seeding. The long-term proliferation of the MFCs in the centrifugal group was also significantly higher than that in the other groups. The results of the MSCs were similar to those of the MFCs. The centrifugal seeding method could significantly improve MFCs or MSCs distribution and proliferation on the DCB scaffolds, thus providing a simple, cost-effective, and effective cell-seeding protocol for tissue-engineered meniscus.

  2. Artificial life and life artificialization in Tron

    Directory of Open Access Journals (Sweden)

    Carolina Dantas Figueiredo

    2012-12-01

    Full Text Available Cinema constantly shows the struggle between the men and artificial intelligences. Fiction, and more specifically fiction films, lends itself to explore possibilities asking “what if?”. “What if”, in this case, is related to the eventual rebellion of artificial intelligences, theme explored in the movies Tron (1982 and Tron Legacy (2010 trat portray the conflict between programs and users. The present paper examines these films, observing particularly the possibility programs empowering. Finally, is briefly mentioned the concept of cyborg as a possibility of response to human concerns.

  3. Oral bacterial adhesion forces to biomaterial surfaces constituting the bracket-adhesive-enamel junction in orthodontic treatment

    NARCIS (Netherlands)

    Mei, Li; Busscher, Henk J; van der Mei, Henny C; Chen, Yangxi; de Vries, Joop; Ren, Yijin

    2009-01-01

    Bacterial adhesion to biomaterial surfaces constituting the bracket-adhesive-enamel junction represents a growing problem in orthodontics, because bacteria can adversely affect treatment by causing demineralization of the enamel surface around the brackets. It is important to know the forces with wh

  4. Tensão superficial dinâmica e ângulo de contato de soluções aquosas com surfatantes em superfícies artificiais e naturais Dynamic surface tension and contact angle of water solutions with spray surfactants in artificial and natural surfaces

    Directory of Open Access Journals (Sweden)

    Cristina A. R. Iost

    2010-08-01

    Full Text Available O trabalho objetivou avaliar o efeito de surfatantes em soluções aquosas sobre a tensão superficial dinâmica e ângulo de contato das gotas em diferentes superfícies: artificiais (lâmina de vidro e de óxido de alumínio e naturais (superfícies adaxiais de folhas de Euphorbia heterophylla, Ipomoea grandifolia e Brachiaria plantaginea. Seis formulações de surfatantes (Antideriva®; Uno®; Pronto 3®; Li-700®; Supersil® e Silwet L-77®, respectivamente nas doses recomendadas do produto comercial (0,050; 0,025; 0,100; 0,250; 0,100 e 0,100 % v v-1 e o dobro delas, foram avaliadas em soluções aquosas. A tensão superficial dinâmica e o ângulo de contato formado sobre as superfícies naturais foram medidos por tensiômetro. Os ângulos de contato formados pelas gotas nas superfícies artificiais foram obtidos por análise de imagens capturadas por uma câmera digital. Os surfatantes influenciam nas propriedades físico-químicas de soluções aquosas. As soluções contendo os surfatantes Silwet L-77® e Supersil®; nas doses de 0,100 e 0,200% v v-1; proporcionaram maiores reduções na tensão superficial dinâmica e menores ângulos de contato das gotas sobre as superfícies artificiais e naturais. Os surfatantes organossiliconados em solução aquosa foram mais eficientes na redução da tensão superficial e proporcionaram maior molhamento de superfícies natural e artificial. Em alvos naturais, essas propriedades obtidas com organossiliconados são dependentes das características de superfície das espécies vegetais.The aim of the work was to evaluate the effect of surfactants in water solutions on dynamic surface tension and contact angle formed by the spray droplets in different surfaces: artificial (glass and aluminum oxide slides and natural (leaves surface of three species of weeds: Euphorbia heterophylla, Ipomoea grandifolia e Brachiaria plantaginea. Were studied six surfactants formulations (AntiderivaTM; UnoTM; Pronto 3TM

  5. Artificial insemination in poultry

    Science.gov (United States)

    Artificial insemination is a relative simple yet powerful tool geneticists can employ for the propagation of economically important traits in livestock and poultry. In this chapter, we address the fundamental methods of the artificial insemination of poultry, including semen collection, semen evalu...

  6. Scientific Objectives of Small Carry-on Impactor (SCI) and Deployable Camera 3 Digital (DCAM3-D): Observation of an Ejecta Curtain and a Crater Formed on the Surface of Ryugu by an Artificial High-Velocity Impact

    Science.gov (United States)

    Arakawa, M.; Wada, K.; Saiki, T.; Kadono, T.; Takagi, Y.; Shirai, K.; Okamoto, C.; Yano, H.; Hayakawa, M.; Nakazawa, S.; Hirata, N.; Kobayashi, M.; Michel, P.; Jutzi, M.; Imamura, H.; Ogawa, K.; Sakatani, N.; Iijima, Y.; Honda, R.; Ishibashi, K.; Hayakawa, H.; Sawada, H.

    2016-10-01

    The Small Carry-on Impactor (SCI) equipped on Hayabusa2 was developed to produce an artificial impact crater on the primitive Near-Earth Asteroid (NEA) 162173 Ryugu (Ryugu) in order to explore the asteroid subsurface material unaffected by space weathering and thermal alteration by solar radiation. An exposed fresh surface by the impactor and/or the ejecta deposit excavated from the crater will be observed by remote sensing instruments, and a subsurface fresh sample of the asteroid will be collected there. The SCI impact experiment will be observed by a Deployable CAMera 3-D (DCAM3-D) at a distance of ˜1 km from the impact point, and the time evolution of the ejecta curtain will be observed by this camera to confirm the impact point on the asteroid surface. As a result of the observation of the ejecta curtain by DCAM3-D and the crater morphology by onboard cameras, the subsurface structure and the physical properties of the constituting materials will be derived from crater scaling laws. Moreover, the SCI experiment on Ryugu gives us a precious opportunity to clarify effects of microgravity on the cratering process and to validate numerical simulations and models of the cratering process.

  7. Onion artificial muscles

    Science.gov (United States)

    Chen, Chien-Chun; Shih, Wen-Pin; Chang, Pei-Zen; Lai, Hsi-Mei; Chang, Shing-Yun; Huang, Pin-Chun; Jeng, Huai-An

    2015-05-01

    Artificial muscles are soft actuators with the capability of either bending or contraction/elongation subjected to external stimulation. However, there are currently no artificial muscles that can accomplish these actions simultaneously. We found that the single layered, latticed microstructure of onion epidermal cells after acid treatment became elastic and could simultaneously stretch and bend when an electric field was applied. By modulating the magnitude of the voltage, the artificial muscle made of onion epidermal cells would deflect in opposing directions while either contracting or elongating. At voltages of 0-50 V, the artificial muscle elongated and had a maximum deflection of -30 μm; at voltages of 50-1000 V, the artificial muscle contracted and deflected 1.0 mm. The maximum force response is 20 μN at 1000 V.

  8. Principles of calcite dissolution in human and artificial otoconia.

    Directory of Open Access Journals (Sweden)

    Leif Erik Walther

    Full Text Available Human otoconia provide mechanical stimuli to deflect hair cells of the vestibular sensory epithelium for purposes of detecting linear acceleration and head tilts. During lifetime, the volume and number of otoconia are gradually reduced. In a process of degeneration morphological changes occur. Structural changes in human otoconia are assumed to cause vertigo and balance disorders such as benign paroxysmal positional vertigo (BPPV. The aim of this study was to investigate the main principles of morphological changes in human otoconia in dissolution experiments by exposure to hydrochloric acid, EDTA, demineralized water and completely purified water respectively. For comparison reasons artificial (biomimetic otoconia (calcite gelatin nanocomposits and natural calcite were used. Morphological changes were detected in time steps by the use of environmental scanning electron microscopy (ESEM. Under in vitro conditions three main dissolution mechanisms were identified as causing characteristic morphological changes of the specimen under consideration: pH drops in the acidic range, complex formation with calcium ions and changes of ion concentrations in the vicinity of otoconia. Shifts in pH cause a more uniform reduction of otoconia size (isotropic dissolution whereas complexation reactions and changes of the ionic concentrations within the surrounding medium bring about preferred attacks at specific areas (anisotropic dissolution of human and artificial otoconia. Owing to successive reduction of material, all the dissolution mechanisms finally produce fragments and remnants of otoconia. It can be assumed that the organic component of otoconia is not significantly attacked under the given conditions. Artificial otoconia serve as a suitable model system mimicking chemical attacks on biogenic specimens. The underlying principles of calcite dissolution under in vitro conditions may play a role in otoconia degeneration processes such as BPPV.

  9. Bilateral maxillary sinus floor augmentation with tissue-engineered autologous osteoblasts and demineralized freeze-dried bone

    Directory of Open Access Journals (Sweden)

    Aashish Deshmukh

    2015-01-01

    Full Text Available The pneumatization of the maxillary sinus often results in a lack of sufficient alveolar bone for implant placement. In the last decades, maxillary sinus lift has become a very popular procedure with predictable results. Sinus floor augmentation procedures are generally carried out using autologous bone grafts, bone substitutes, or composites of bone and bone substitutes. However, the inherent limitations associated with each of these, have directed the attention of investigators to new technologies like bone tissue engineering. Bone marrow stromal cells have been regarded as multi-potent cells residing in bone marrow. These cells can be harvested from a person, multiplied outside his body using bioengineering principles and technologies and later introduced into a tissue defect. We present a case where tissue-engineered autologous osteoblasts were used along with demineralized freeze-dried bone for sinus floor augmentation.

  10. Effect of sporadic destratification, seasonal overturn and artificial mixing on CH4 emissions at the surface of a subtropical hydroelectric reservoir (Nam Theun 2 Reservoir, Lao PDR

    Directory of Open Access Journals (Sweden)

    F. Guérin

    2015-07-01

    fluxes from this area were the lowest observed at the reservoir surface. Emissions from this area contributed 15–25 % to total annual emissions although they occur on a surface area representative of less than 1 % of the total reservoir surface. We highly recommend measurements of diffusive fluxes around water intakes in order to evaluate if such results can be generalized.

  11. Viscosity of set-style yogurt as influenced by heat treatment of milk and added demineralized whey powder

    Directory of Open Access Journals (Sweden)

    Đurđević-Denin Jelena D.

    2002-01-01

    Full Text Available Skim milk powder was reconstituted to obtain milk A (with 8.44% TS. Milk sample A was standardized with different amounts of demineralized whey powder (DWP to obtain milk B (with 9.71% TS and milk C (with 10.75% TS. Milk samples were heat treated at 85ºC/20 min and 90ºC/10 min, respectively. Untreated milk was used as control. Milk samples were inoculated with 2.5% of commercial yogurt culture (containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the ratio 1:1 at 43ºC. Samples were incubated until pH 4.6 was reached. Samples were immediately cooled to 4ºC and held at that temperature until analyses. Measurements of viscosity were done with Brookfield DV-E Viscometer. Spindle No 3 at 20 rpm was used for all samples. After 1 day of storage, set-style yogurt samples produced from untreated milk had the highest, while samples produced from milk heat treated at 90ºC/10 min the smallest initial viscosity, regadless of the dry matter content and composition. Average viscosity of set-style yogurts decreased with intensifying temperature of applied heat-treatment. During storage, set-style yogurt samples produced from milk heat treated at 90ºC/10 min had the least pronounced decrease of viscosity during shearing. After 14 days of storage, set-style yogurt samples produced from milk standardized with demineralized whey powder had higher viscosity than samples produced from basis milk.

  12. The Effect of Artificial Aging on The Bond Strength of Heat-activated Acrylic Resin to Surface-treated Nickel-chromium-beryllium Alloy

    Science.gov (United States)

    Al Jabbari, Youssef S.; Zinelis, Spiros; Al Taweel, Sara M.; Nagy, William W.

    2016-01-01

    Purpose The debonding load of heat-activated polymethylmethacrylate (PMMA) denture base resin material to a nickel-chromium-beryllium (Ni-Cr-Be) alloy conditioned by three different surface treatments and utilizing two different commercial bonding systems was investigated. Materials and Methods Denture resin (Lucitone-199) was bonded to Ni-Cr-Be alloy specimens treated with Metal Primer II, the Rocatec system with opaquer and the Rocatec system without opaquer. Denture base resin specimens bonded to non-treated sandblasted Ni-Cr-Be alloy were used as controls. Twenty samples for each treatment condition (80 specimens) were tested. The 80 specimens were divided into two categories, thermocycled and non-thermocycled, containing four groups of ten specimens each. The non-thermocycled specimens were tested after 48 hours’ storage in room temperature water. The thermocycled specimens were tested after 2,000 cycles in 4°C and 55°C water baths. The debonding load was calculated in Newtons (N), and collected data were subjected by non parametric test Kruskal-Wallis One Way Analysis of Variance on Ranks and Dunn’s post hoc test at the α = 0.05. Results The Metal Primer II and Rocatec system without opaquer groups produced significantly higher bond strengths (119.9 and 67.6 N), respectively, than did the sandblasted and Rocatec system with opaquer groups, where the bond strengths were 2.6 N and 0 N, respectively. The Metal Primer II was significantly different from all other groups (P<0.05). The bond strengths of all groups were significantly decreased (P<0.05) after thermocycling. Conclusions Although thermocycling had a detrimental effect on the debonding load of all surface treatments tested, the Metal Primer II system provided higher values among all bonding systems tested, before and after thermocycling. PMID:27335613

  13. 酪蛋白磷酸肽-非结晶型磷酸钙与含氟制剂抑制牙釉质脱矿的比较研究%Comparative studies of casein phosphopeptide-amorphous calcium phosphate and fluoride products in inhibiting enamel demineralization

    Institute of Scientific and Technical Information of China (English)

    张春波; 孙新华; 侯旭; 闫阔

    2012-01-01

    ,then applied separately with CPP-ACP,CPP-ACP + fluoride mouth rinses,fluoride mouth rinses,fluoride glass ionomer protection,fluoride resin binder and fluoride varnish on labial enamel.The samples were dipped into an artificial saliva solution ( 37 ℃ ).Then all samples were examined with atomic force microscope ( AFM ) at the end of first,second and third monthes.Results At the end of the first month,surface roughness in group D [ ( 114 ±1 ) nm] was significantly lower than that in group G[ ( 172 ±9) nm].At the end of the second month and the third month,significant difference was found in surface roughness between group G and the rest of groups (P < 0.05 ) ; between group B and the rest of groups ; and between group C and groups ( D,E and F).Conclusions CPP-ACP and fluoride could both inhibit enamel demineralization in vitro. Solid fluoride (groups D,E and F) had better results than liquid fluoride (group C).

  14. Artificial intelligence in medicine.

    Science.gov (United States)

    Ramesh, A. N.; Kambhampati, C.; Monson, J. R. T.; Drew, P. J.

    2004-01-01

    INTRODUCTION: Artificial intelligence is a branch of computer science capable of analysing complex medical data. Their potential to exploit meaningful relationship with in a data set can be used in the diagnosis, treatment and predicting outcome in many clinical scenarios. METHODS: Medline and internet searches were carried out using the keywords 'artificial intelligence' and 'neural networks (computer)'. Further references were obtained by cross-referencing from key articles. An overview of different artificial intelligent techniques is presented in this paper along with the review of important clinical applications. RESULTS: The proficiency of artificial intelligent techniques has been explored in almost every field of medicine. Artificial neural network was the most commonly used analytical tool whilst other artificial intelligent techniques such as fuzzy expert systems, evolutionary computation and hybrid intelligent systems have all been used in different clinical settings. DISCUSSION: Artificial intelligence techniques have the potential to be applied in almost every field of medicine. There is need for further clinical trials which are appropriately designed before these emergent techniques find application in the real clinical setting. PMID:15333167

  15. Ability of laser fluorescence device associated with fluorescent dyes in detecting and quantifying early smooth surface caries lesions

    Science.gov (United States)

    Mendes, Fausto M.; de Oliveira, Elisabeth; de Faria, Dalva L. A.; Nicolau, José

    2006-03-01

    A laser fluorescence (LF) device is a portable tool, but it does not measure minor mineral changes. Our in vitro study aim is to propose the association of an LF with two fluorescent dyes and to evaluate the performance in detecting and quantifying early demineralization. Artificial caries lesions are created in 40 primary canine teeth using a demineralizing solution (pH=4.8) for 12, 24, 48, and 96 h. LF measurements are performed with DIAGNOdent after demineralization in these samples and in 20 sound primary teeth. Measurements with LF with 0.2-mM tetrakis(N-methylpyridyl)porphyrin (LF TMPyP) and with 4-mM protoporphyrin IX (LF PPIX) are made. The amount of calcium loss is determined by atomic emission spectrometry. A correlation between LF and LF with dyes and mineral loss and receiver operating characteristics analysis are performed, as well as comparisons of sensitivity, specificity, and accuracy values. Significant correlation is obtained with LF TMPyP and mineral loss of lesions demineralized for 24, 48, and 96 h. Better performance is achieved with LF TMPyP for all parameters than with LF alone. LF PPIX does not present good results. In conclusion, LF TMPyP provides good performance in detecting and quantifying very early enamel caries lesions.

  16. Clinical research of the effect of fluoride foam on the prevention of enamel demineralization during fixed orthodontic%氟化泡沫在固定正畸过程中预防釉质脱矿的临床研究

    Institute of Scientific and Technical Information of China (English)

    唐璐; 杨四维; 庞兰; 李宇

    2015-01-01

    目的::研究1.23%氟化泡沫在固定正畸治疗过程中预防釉质脱矿的临床效果。方法:经签字同意进入实验的固定正畸患者40例,随机分为A、B两组,每组20名。A组单纯口腔卫生措施,B组在口腔卫生措施的基础上使用1.23%氟化泡沫。两组患者从治疗起始,每月均使用Canon60D专业相机拍摄一次牙牙合照片,共13次,观察时间为13个月。临床检测指标为牙面是否出现新增的白垩色斑点或龋洞,计算牙釉质脱矿指数(EDI)。结果:①从12次牙釉质脱矿变化看,A、B两组的牙釉质脱矿率均随着时间的延长而增高;②两组EDI指数的平均数:A组高于B组,有统计学意义(t=2.929,P=0.008)。结论:①固定正畸所引起的牙釉质脱矿的发生率和严重程度与正畸时间呈正相关;②在口腔卫生措施的基础上使用1.23%氟化泡沫预防固定正畸过程中的牙釉质脱矿是一种有效的措施。%Objective: To study the effect of 1.23% fluoride foam in prevention of enamel demineralization during fixed orthodontic. Methods: 40 fixed orthodontic patients were randomly divided into group A, taken simple oral hygiene measures, and group B, 1.23%fluoride foam was used besides simple oral hygiene measures. From the beginning of treatment, patients of both groups were taken photos of teeth monthly with Canon60D professional photo camera with a total of 13 times, the observation time was 13 months. The clinical index was whether there was new chalk colored spots or cavities on the surface of tooth and enamel demineralization index (EDI) was calculated. Results: ①Judged from the changes of enamel demineralization in 12 observations, enamel demineralization rates in both groups were increased with the orthodontic time. ②the average EDI of A group was higher than that of B group (t = 2.929, P= 0.008), and statistically significant. Conclusions: ①The incidence and severity of enamel

  17. Development of artificial articular cartilage.

    Science.gov (United States)

    Oka, M; Ushio, K; Kumar, P; Ikeuchi, K; Hyon, S H; Nakamura, T; Fujita, H

    2000-01-01

    Attempts have been made to develop an artificial articular cartilage on the basis of a new viewpoint of joint biomechanics in which the lubrication and load-bearing mechanisms of natural and artificial joints are compared. Polyvinyl alcohol hydrogel (PVA-H), 'a rubber-like gel', was investigated as an artificial articular cartilage and the mechanical properties of this gel were improved through a new synthetic process. In this article the biocompatibility and various mechanical properties of the new improved PVA-H is reported from the perspective of its usefulness as an artificial articular cartilage. As regards lubrication, the changes in thickness and fluid pressure of the gap formed between a glass plate and the specimen under loading were measured and it was found that PVA-H had a thicker fluid film under higher pressures than polyethylene (PE) did. The momentary stress transmitted through the specimen revealed that PVA-H had a lower peak stress and a longer duration of sustained stress than PE, suggesting a better damping effect. The wear factor of PVA-H was approximately five times that of PE. Histological studies of the articular cartilage and synovial membranes around PVA-H implanted for 8-52 weeks showed neither inflammation nor degenerative changes. The artificial articular cartilage made from PVA-H could be attached to the underlying bone using a composite osteochondral device made from titanium fibre mesh. In the second phase of this work, the damage to the tibial articular surface after replacement of the femoral surface in dogs was studied. Pairs of implants made of alumina, titanium or PVA-H on titanium fibre mesh were inserted into the femoral condyles. The two hard materials caused marked pathological changes in the articular cartilage and menisci, but the hydrogel composite replacement caused minimal damage. The composite osteochondral device became rapidly attached to host bone by ingrowth into the supporting mesh. The clinical implications of

  18. Artificial recharge of groundwater: hydrogeology and engineering

    Science.gov (United States)

    Bouwer, Herman

    2002-02-01

    Artificial recharge of groundwater is achieved by putting surface water in basins, furrows, ditches, or other facilities where it infiltrates into the soil and moves downward to recharge aquifers. Artificial recharge is increasingly used for short- or long-term underground storage, where it has several advantages over surface storage, and in water reuse. Artificial recharge requires permeable surface soils. Where these are not available, trenches or shafts in the unsaturated zone can be used, or water can be directly injected into aquifers through wells. To design a system for artificial recharge of groundwater, infiltration rates of the soil must be determined and the unsaturated zone between land surface and the aquifer must be checked for adequate permeability and absence of polluted areas. The aquifer should be sufficiently transmissive to avoid excessive buildup of groundwater mounds. Knowledge of these conditions requires field investigations and, if no fatal flaws are detected, test basins to predict system performance. Water-quality issues must be evaluated, especially with respect to formation of clogging layers on basin bottoms or other infiltration surfaces, and to geochemical reactions in the aquifer. Clogging layers are managed by desilting or other pretreatment of the water, and by remedial techniques in the infiltration system, such as drying, scraping, disking, ripping, or other tillage. Recharge wells should be pumped periodically to backwash clogging layers. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s10040-001-0182-4.

  19. Treating of Simulated Sewage by Artificial Wetland with Surface Flowing Water%表面流人工湿地处理农村生活污水的研究

    Institute of Scientific and Technical Information of China (English)

    虞益江

    2011-01-01

    文章通过小试装置研究了表面流人工湿地对人工模拟生活污水的处理效果及相关运行参数.实验结果表明,表面流人工湿地系统对污水中的COD,TN,TP均有较好的综合净化能力,对各种污染物指标的去除率可分别达到COD 75%,TN 75%,TP 73%,其中COD和TN达到一级排放标准分别需3d和4d的表观停留时间,TP要达到二级排放标准则需6d的表观停留时间.而且,湿地植物对TN和TP的去除有比较明显的促进作用.%Simulated sewage was treated by laboratory artificial wetland with surface flowing water, and the performance and related operation parameters were investigated. The result showed that the removal of COD, TN, and TP reached 75% , 75% , and 73% respectively. And the COD and TN could reach discharge standard Class 1 under 3 d and 4 d of apparent retention time respectively, but 6 d of apparent retention time was needed for TP reaching discharge standard Class 2. In addtion, the wetland plants could obviously improve the TN and TP removal.

  20. Biological characteristics and clinical application of artificial hip joint weight-bearing surface materials%人工髋关节负重面材料的生物特性及其临床应用

    Institute of Scientific and Technical Information of China (English)

    唐焜

    2012-01-01

    背景:人工髋关节假体材料对髋关节置换的成功率及对患者治愈率起到决定性作用.目的:评价不同组合方式髋关节负重面材料的性能及置入体内与机体的生物相容性.方法:以"全髋关节置换,人工髋关节,金属,陶瓷,聚乙烯,生物相容性,临床应用;total hip replacement,Artificialhip,prosthetic materials,Biocompatibility,clinical application"为关键词,应用计算机检索2001-01/2011-12 万方数据库、PubMed 数据库有关人工髋关节负重面生物材料与宿主生物相容性的文章.结果与结论:金属-超高分子量聚乙烯组合是目前常用的组合,也是衡量其他组合的金标准,但其磨损颗粒引起周围组织反应导致骨溶解和无菌性假体松动;金属-高交联聚乙烯、金属-金属、陶瓷-陶瓷和陶瓷-聚乙烯组合均在一定程度上减少了磨损,但金属离子毒性、陶瓷脆性、造价高等仍然是需要解决的问题.理想的负重面材料应具有良好生物相容、耐蚀性、耐磨性、耐疲劳性、强韧性好等特点,目前人工髋关节负重面组合材料各有优缺点.因此,临床医师针对不同的患者,采取个体化治疗原则,综合患者病情和经济状况等多方面因素,选择合适假体组合类型,以期达到最佳临床疗效.%BACKGROUND: Artificial hip prosthesis materials play a decisive role in the success rates of hip replacement and the recovery rate for patientsOBJECTIVE: To evaluate the properties of hip joint weight-bearing surface materials with different combinations, as well as the biocompatibihty of the materials and the host after implanted in vivoMETHODS: The keyword of "total hip replacement, artificial hip joint, metal, ceramic, polyethylene, biocompatibihty, clinical application" in Chinese and "total hip replacement, artificial hip, prosthetic materials, biocompatibihty, clinical application" in English were used to retrieve the articles published from January 2001 to

  1. A modeling study by response surface methodology and artificial neural network on culture parameters optimization for thermostable lipase production from a newly isolated thermophilic Geobacillus sp. strain ARM

    Directory of Open Access Journals (Sweden)

    Basri Mahiran

    2008-12-01

    Full Text Available Abstract Background Thermostable bacterial lipases occupy a place of prominence among biocatalysts owing to their novel, multifold applications and resistance to high temperature and other operational conditions. The capability of lipases to catalyze a variety of novel reactions in both aqueous and nonaqueous media presents a fascinating field for research, creating interest to isolate novel lipase producers and optimize lipase production. The most important stages in a biological process are modeling and optimization to improve a system and increase the efficiency of the process without increasing the cost. Results Different production media were tested for lipase production by a newly isolated thermophilic Geobacillus sp. strain ARM (DSM 21496 = NCIMB 41583. The maximum production was obtained in the presence of peptone and yeast extract as organic nitrogen sources, olive oil as carbon source and lipase production inducer, sodium and calcium as metal ions, and gum arabic as emulsifier and lipase production inducer. The best models for optimization of culture parameters were achieved by multilayer full feedforward incremental back propagation network and modified response surface model using backward elimination, where the optimum condition was: growth temperature (52.3°C, medium volume (50 ml, inoculum size (1%, agitation rate (static condition, incubation period (24 h and initial pH (5.8. The experimental lipase activity was 0.47 Uml-1 at optimum condition (4.7-fold increase, which compared well to the maximum predicted values by ANN (0.47 Uml-1 and RSM (0.476 Uml-1, whereas R2 and AAD were determined as 0.989 and 0.059% for ANN, and 0.95 and 0.078% for RSM respectively. Conclusion Lipase production is the result of a synergistic combination of effective parameters interactions. These parameters are in equilibrium and the change of one parameter can be compensated by changes of other parameters to give the same results. Though both RSM and

  2. Principles of artificial intelligence

    CERN Document Server

    Nilsson, Nils J

    1980-01-01

    A classic introduction to artificial intelligence intended to bridge the gap between theory and practice, Principles of Artificial Intelligence describes fundamental AI ideas that underlie applications such as natural language processing, automatic programming, robotics, machine vision, automatic theorem proving, and intelligent data retrieval. Rather than focusing on the subject matter of the applications, the book is organized around general computational concepts involving the kinds of data structures used, the types of operations performed on the data structures, and the properties of th

  3. The Artificial Anal Sphincter

    OpenAIRE

    Christiansen, John

    2000-01-01

    The artificial anal sphincter as treatment for end stage anal incontinence was first described in 1987. Published series concern a total of 42 patients, with a success rate of approximately 80%. Infection has been the most serious complication, but a number of technical complications related to the device have also occurred and required revisional procedures in 40% to 60% of the patients. The artificial anal sphincter may be used for the same indications as dynamic graciloplasty except in pat...

  4. The effect of acidulated phosphate fluoride application on dental enamel surfaces hardness

    Directory of Open Access Journals (Sweden)

    Edhie Arief P

    2007-09-01

    Full Text Available Enamel demineralization by acid is the first step of caries process. It has recently been shown that acidulated phosphate fluoride (APF can maintain the hardness of enamel surface. The aim of this study was examine the effect of APF application in the hardest of enamel surface. Fifty extracted teeth were cut at their crown, 40 teeth were taken randomly then divided into 4 groups, group 1 as the control, group 2 was treated with APF for 1 minute, group 3 for 4 minutes and group 4 for 7 minutes, then all the samples were washed with demineralized water. To see the effect of APF, all of the samples were soaked in lactic acid demineralization solution with pH 4,5 for 72 hours., the hardness of the surfaces of those samples before and after the treatment was measured by Micro Vickers Hardness Tester. The data were analyzed using One-Way ANOVA and LSD tests. In conclusion, 1.23% APF gel can reduce higher enamel demineralization.

  5. Long-Wave Infrared Thermophotonic Imaging of Demineralization in Dental Hard Tissue

    Science.gov (United States)

    Ojaghi, A.; Parkhimchyk, A.; Tabatabaei, N.

    2016-08-01

    Dental caries remains the most prevalent chronic disease in both children and adults worldwide. To address this prevalence through disease prevention and management, dentists need tools capable of detecting caries at early stages of formation. Looking into the physics of light propagation in teeth, this study presents a clinically and commercially viable platform technology for thermophotonic detection of early dental caries using an inexpensive long-wavelength infrared (LWIR; 8 μm to 14 μm) camera. The developed system incorporates intensity-modulated light to generate a thermal-wave field inside enamel and uses the subsequent infrared emission of the thermal-wave field to detect early caries. It was found that the greater light absorption at caries sites shifts the thermal-wave field centroid, providing contrast between early caries and intact enamel. Use of LWIR detection band in dental samples is novel and beneficial over the conventional mid-wavelength infrared band (3 μm to 5 μm) as it suppresses the masking effect of the instantaneous radiative emission from subsurface features due to the minimal transmittance of enamel in the LWIR band. The efficacy of the LWIR system is verified though experiments carried out on nonbiological test samples as well as on teeth with natural and artificially induced caries. The results suggest that the developed LWIR technology is an affordable early dental caries detection system suitable for commercialization/translation to Dentistry.

  6. Adsorption of sulfonamides to demineralized pine wood biochars prepared under different thermochemical conditions

    International Nuclear Information System (INIS)

    The main objective of this study was to understand the key factors and mechanisms controlling adsorption of sulfonamides to biochars. Batch adsorption experiments were performed for sulfamethoxazole and sulfapyridine to three pine-wood biochars prepared under different thermochemical conditions: pyrolysis at 400 °C (C400) and 500 °C (C500), and pyrolysis at 500 °C followed with hydrogenation (C500-H). For both sulfonamides, the adsorbent surface area-normalized adsorption was stronger to C500 than to C400. This is attributable to the enhanced π–π electron-donor–acceptor interaction with the carbon surface of C500 due to the higher degree of graphitization. Despite the relatively large difference in surface O-functionality content between C500 (12.2%) and C500-H (6.6%), the two biochars exhibited nearly identical adsorbent surface area-normalized adsorption, indicating negligible role of surface O-functionalities in the adsorption to these adsorbents. Effects of solution chemistry conditions (pH, Cu2+, and dissolved soil humic acid) on adsorption were examined. -- Highlights: • Adsorption to biochars is dominated by π–π electron-donor–acceptor (EDA) interaction. • Graphitic surfaces of biochars are predominant adsorption sites. • Surface O-functionalities of biochars play minor roles in adsorption. • Adsorption affinities are markedly affected by Cu ions and humic acids. -- Adsorption of sulfonamides to biochars is dominated by π– electron-donor–acceptor (EDA) interaction with the graphitic surface

  7. Biomimetic Remineralization of Demineralized Dentine Using Scaffold of CMC/ACP Nanocomplexes in an In Vitro Tooth Model of Deep Caries

    OpenAIRE

    Chen, Zhen; Cao, Shansong; Wang, Haorong; Li, Yanqiu; Kishen, Anil; Deng, Xuliang; Yang, Xiaoping; Wang, Yinghui; Cong, Changhong; Wang, Huajun; Zhang, Xu

    2015-01-01

    Currently, it is still a tough task for dentists to remineralize dentine in deep caries. The aim of this study was to remineralize demineralized dentine in a tooth model of deep caries using nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) based on mimicking the stabilizing effect of dentine matrix protein 1 (DMP1) on ACP in the biomineralization of dentine. The experimental results indicate that CMC can stabilize ACP to form nanocomplexes of CMC/ACP, which is abl...

  8. Intervertebral disk-like biphasic scaffold—demineralized bone matrix cylinder and poly(polycaprolactone triol malate)—for interbody spine fusion

    OpenAIRE

    Li Jin; Yuqing Wan; Shimer, Adam L.; Shen, Francis H.; Li, Xudong J

    2012-01-01

    Interbody fusion is an established procedure to preserve disk height and anterior fusion, but fusion with autografts, allografts, and metallic cages has its endogenous shortcomings. The objective of this study is to investigate whether a biphasic scaffold model, the native demineralized bone matrix cylinder in conjunction with degradable biomaterial poly(polycaprolactone triol malate), can be employed as a biological graft for interbody fusion. The poly(polycaprolactone triol malate) was synt...

  9. Comparative evaluation of demineralization of radicular dentin with 17% ethylenediaminetetraacetic acid, 10% citric acid, and MTAD at different time intervals: An in vitro study

    OpenAIRE

    Kumar, Yogender; Lohar, Jitendra; Bhat, Sureka; Bhati, Manisha; Gandhi, Aanesh; Mehta, Abhishek

    2016-01-01

    Background: The smear layer has the capability to protect the bacteria within the dentinal tubules from intracanal medicament. After removal of the smear layer from infected root canals, it allows disinfection of the entire root canal. The smear layer compromising the seal between the root canal sealer and root canal wall also decreases the penetration of irrigants into dentinal tubules. Aims: This study compares the amount of phosphorous liberated and demineralization of the radicular dentin...

  10. Clinical and biometrical evaluation of socket preservation using demineralized freeze-dried bone allograft with and without the palatal connective tissue as a biologic membrane

    OpenAIRE

    Hamid Moghaddas; Mohammad Reza Amjadi; Narges Naghsh

    2012-01-01

    Background: Alveolar ridge preservation following tooth extraction has the ability to maintain the ridge dimensions and allow the implant placement in an ideal position fulfilling both functional and aesthetic results. The aim of this study was to evaluate the efficacy of the palatal connective tissue as a biological membrane for socket preservation with demineralized freeze-dried bone allograft (DFDBA). Materials and Methods: Twelve extraction sites were treated with DFDBA with (case gro...

  11. Corrosion Inhibition of Titanium in Artificial Saliva Containing Fluoride

    OpenAIRE

    Latifa KINANI; Abdelilah CHTAINI

    2007-01-01

    The objective of this study was to demonstrate the effect of eugenol on the titanium corrosion in artificial saliva enriched with eugenol at different concentration. The corrosion behaviour and titanium surface characterization were investigated by electrochemical measurements and SEM.

  12. Corrosion Inhibition of Titanium in Artificial Saliva Containing Fluoride

    OpenAIRE

    Latifa KINANI; Rachida NAJIH; Abdelilah CHTAINI

    2008-01-01

    The objective of this study was to demonstrate the effect of eugenol on the titanium corrosion in artificial saliva enriched with eugenol at different concentration. The corrosion behaviour and titanium surface characterization were investigated by electrochemical measurements and SEM.

  13. Biomimetic remineralization of demineralized dentine using scaffold of CMC/ACP nanocomplexes in an in vitro tooth model of deep caries.

    Directory of Open Access Journals (Sweden)

    Zhen Chen

    Full Text Available Currently, it is still a tough task for dentists to remineralize dentine in deep caries. The aim of this study was to remineralize demineralized dentine in a tooth model of deep caries using nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP based on mimicking the stabilizing effect of dentine matrix protein 1 (DMP1 on ACP in the biomineralization of dentine. The experimental results indicate that CMC can stabilize ACP to form nanocomplexes of CMC/ACP, which is able to be processed into scaffolds by lyophilization. In the single-layer collagen model, ACP nanoparticles are released from scaffolds of CMC/ACP nanocomplexes dissolved and then infiltrate into collagen fibrils via the gap zones (40 nm to accomplish intrafibrillar mineralization of collagen. With this method, the completely demineralized dentine was partially remineralized in the tooth mode. This is a bottom-up remineralizing strategy based on non-classical crystallization theory. Since nanocomplexes of CMC/ACP show a promising effect of remineralization on demineralized dentine via biomimetic strategy, thereby preserving dentinal tissue to the maximum extent possible, it would be a potential indirect pulp capping (IPC material for the management of deep caries during vital pulp therapy based on the concept of minimally invasive dentistry (MID.

  14. Effect of in-situ solvent soaking and heating pre-treatment on coal conversion and oil yield during liquefaction of demineralized low-rank Malaysian coal

    Energy Technology Data Exchange (ETDEWEB)

    M.A.M. Ishak; M.F. Abdullah; K. Ismail; M.O.A. Kadir; A.R. Mohamed [University Technology MARA, Perlis (Malaysia). Fuel Combustion Research Laboratory, Faculty of Applied Sciences

    2005-07-01

    The effect of in-situ solvent soaking and heating (SSH) pre-treatment on demineralized low-rank Malaysian coal towards coal conversion and oil yield during direct liquefaction was investigated. Demineralization of coal was carried out by leaching with strong protic acids such as HCl, HF and HNO{sub 3} whereby more than 95 % of mineral content in the coal was reduced. Apparently, the mineral matter that was removed by the HCl treatment (i.e. cationics) exhibits more catalytic effect during the liquefaction process. The reduction in the mineral content increased the coal porosity that enabled the solvent to penetrate into the coal macropores during the SSH pre-treatment process. The results of liquefaction on the pre-treated SSH demineralized coal at 420{sup o}C and at 4 MPa, however show comparable amount of coal conversion with slightly lower amount of oil yield being obtained with comparison to the raw and SSH-raw coals. Thus, besides the in-situ solvent soaking and heating pre-treatment, the presence of mineral matters in coal prove to be beneficial during coal liquefaction process.

  15. Effect of various particle size hydroxyapatite on remineralization of artifi-cial initial enamel caries%不同粒径羟基磷灰石对人工早期龋再矿化作用的研究

    Institute of Scientific and Technical Information of China (English)

    刘成霞; 申晓青; 徐平平

    2015-01-01

    目的:研究不同粒径羟基磷灰石( HA)对人工早期龋的再矿化作用。方法:应用离体人恒前磨牙制备早期釉质龋标本50个,随机分为5组(n=10):阳性对照组(NaF溶液)、阴性对照组(去离子水)、30 nm HA组、60 nm HA组和12μm HA组,用显微硬度计检测标本脱矿前后表面显微硬度,并用扫描电镜观察各组样本脱矿前后的形态;按照分组进行早期龋体外循环实验12 d,同法测定体外循环后各组样本的表面显微硬度,并观察其形态。结果:与阴性对照组相比,各HA组均能提高标本的表面显微硬度,且随着粒径的减小,其表面显微硬度增大( F=86.272,P<0.001)。扫描电镜下观察,30 nm HA组和60 nm HA组的脱矿区有针状或短棒状晶体颗粒沉积,表面变得均匀、平整,且以30 nm HA组的再矿化效果更佳,12μm HA组的再矿化效果不明显。结论:HA能有效促进早期釉质龋的再矿化;纳米级HA优于微米级HA,且随着粒径的减小,其再矿化效果更佳。%Aim:To explore the effect of various particle size hydroxyapatite ( HA) on remineralization of artificial ini-tial enamel caries .Methods:Fifty human premolars were prepared for artificial enamel caries specimens , and these speci-mens were randomly allocated into 5 groups(n=10):positive control group(NaF solution), negative control group(deion-ized water), 30 nm HA group, 60 nm HA group and 12 μm HA group.Before and after demineralization, the surface mi-crohardness of the specimens was measured by microhardness tester and the morphologies of the specimens were observed by scanning electron microscope .Then after the experiment of 12 d cycling in vitro , the surface microhardness of each group′s specimens was measured and the morphologies were observed again .Results:Compared with negative control group , all the 3 HA groups could significantly improve the surface microhardness of

  16. Artificial muscles on heat

    Science.gov (United States)

    McKay, Thomas G.; Shin, Dong Ki; Percy, Steven; Knight, Chris; McGarry, Scott; Anderson, Iain A.

    2014-03-01

    Many devices and processes produce low grade waste heat. Some of these include combustion engines, electrical circuits, biological processes and industrial processes. To harvest this heat energy thermoelectric devices, using the Seebeck effect, are commonly used. However, these devices have limitations in efficiency, and usable voltage. This paper investigates the viability of a Stirling engine coupled to an artificial muscle energy harvester to efficiently convert heat energy into electrical energy. The results present the testing of the prototype generator which produced 200 μW when operating at 75°C. Pathways for improved performance are discussed which include optimising the electronic control of the artificial muscle, adjusting the mechanical properties of the artificial muscle to work optimally with the remainder of the system, good sealing, and tuning the resonance of the displacer to minimise the power required to drive it.

  17. Artificial vision workbench.

    Science.gov (United States)

    Frenger, P

    1997-01-01

    Machine vision is an important component of medical systems engineering. Inexpensive miniature solid state cameras are now available. This paper describes how these devices can be used as artificial retinas, to take snapshots and moving pictures in monochrome or color. Used in pairs, they produce a stereoscopic field of vision and enable depth perception. Macular and peripheral vision can be simulated electronically. This paper also presents the author's design of an artificial orbit for this synthetic eye. The orbit supports the eye, protects it, and provides attachment points for the ocular motion control system. Convergence and image fusion can be produced, and saccades simulated, along with the other ocular motions. The use of lenses, filters, irises and focusing mechanisms are also discussed. Typical camera-computer interfaces are described, including the use of "frame grabbers" and analog-to-digital image conversion. Software programs for eye positioning, image manipulation, feature extraction and object recognition are discussed, including the application of artificial neural networks.

  18. Artificial intelligence in nanotechnology.

    Science.gov (United States)

    Sacha, G M; Varona, P

    2013-11-15

    During the last decade there has been increasing use of artificial intelligence tools in nanotechnology research. In this paper we review some of these efforts in the context of interpreting scanning probe microscopy, the study of biological nanosystems, the classification of material properties at the nanoscale, theoretical approaches and simulations in nanoscience, and generally in the design of nanodevices. Current trends and future perspectives in the development of nanocomputing hardware that can boost artificial-intelligence-based applications are also discussed. Convergence between artificial intelligence and nanotechnology can shape the path for many technological developments in the field of information sciences that will rely on new computer architectures and data representations, hybrid technologies that use biological entities and nanotechnological devices, bioengineering, neuroscience and a large variety of related disciplines.

  19. Artificial intelligence in nanotechnology

    International Nuclear Information System (INIS)

    During the last decade there has been increasing use of artificial intelligence tools in nanotechnology research. In this paper we review some of these efforts in the context of interpreting scanning probe microscopy, the study of biological nanosystems, the classification of material properties at the nanoscale, theoretical approaches and simulations in nanoscience, and generally in the design of nanodevices. Current trends and future perspectives in the development of nanocomputing hardware that can boost artificial-intelligence-based applications are also discussed. Convergence between artificial intelligence and nanotechnology can shape the path for many technological developments in the field of information sciences that will rely on new computer architectures and data representations, hybrid technologies that use biological entities and nanotechnological devices, bioengineering, neuroscience and a large variety of related disciplines. (topical review)

  20. Artificial intelligence in nanotechnology

    Science.gov (United States)

    Sacha, G. M.; Varona, P.

    2013-11-01

    During the last decade there has been increasing use of artificial intelligence tools in nanotechnology research. In this paper we review some of these efforts in the context of interpreting scanning probe microscopy, the study of biological nanosystems, the classification of material properties at the nanoscale, theoretical approaches and simulations in nanoscience, and generally in the design of nanodevices. Current trends and future perspectives in the development of nanocomputing hardware that can boost artificial-intelligence-based applications are also discussed. Convergence between artificial intelligence and nanotechnology can shape the path for many technological developments in the field of information sciences that will rely on new computer architectures and data representations, hybrid technologies that use biological entities and nanotechnological devices, bioengineering, neuroscience and a large variety of related disciplines.

  1. Spatially Resolved Artificial Chemistry

    DEFF Research Database (Denmark)

    Fellermann, Harold

    2009-01-01

    Although spatial structures can play a crucial role in chemical systems and can drastically alter the outcome of reactions, the traditional framework of artificial chemistry is a well-stirred tank reactor with no spatial representation in mind. Advanced method development in physical chemistry has...... made a class of models accessible to the realms of artificial chemistry that represent reacting molecules in a coarse-grained fashion in continuous space. This chapter introduces the mathematical models of Brownian dynamics (BD) and dissipative particle dynamics (DPD) for molecular motion and reaction...

  2. Bayesian artificial intelligence

    CERN Document Server

    Korb, Kevin B

    2003-01-01

    As the power of Bayesian techniques has become more fully realized, the field of artificial intelligence has embraced Bayesian methodology and integrated it to the point where an introduction to Bayesian techniques is now a core course in many computer science programs. Unlike other books on the subject, Bayesian Artificial Intelligence keeps mathematical detail to a minimum and covers a broad range of topics. The authors integrate all of Bayesian net technology and learning Bayesian net technology and apply them both to knowledge engineering. They emphasize understanding and intuition but also provide the algorithms and technical background needed for applications. Software, exercises, and solutions are available on the authors' website.

  3. A composite demineralized bone matrix--self assembling peptide scaffold for enhancing cell and growth factor activity in bone marrow.

    Science.gov (United States)

    Hou, Tianyong; Li, Zhiqiang; Luo, Fei; Xie, Zhao; Wu, Xuehui; Xing, Junchao; Dong, Shiwu; Xu, Jianzhong

    2014-07-01

    The need for suitable bone grafts is high; however, there are limitations to all current graft sources, such as limited availability, the invasive harvest procedure, insufficient osteoinductive properties, poor biocompatibility, ethical problems, and degradation properties. The lack of osteoinductive properties is a common problem. As an allogenic bone graft, demineralized bone matrix (DBM) can overcome issues such as limited sources and comorbidities caused by invasive harvest; however, DBM is not sufficiently osteoinductive. Bone marrow has been known to magnify osteoinductive components for bone reconstruction because it contains osteogenic cells and factors. Mesenchymal stem cells (MSCs) derived from bone marrow are the gold standard for cell seeding in tissue-engineered biomaterials for bone repair, and these cells have demonstrated beneficial effects. However, the associated high cost and the complicated procedures limit the use of tissue-engineered bone constructs. To easily enrich more osteogenic cells and factors to DBM by selective cell retention technology, DBM is modified by a nanoscale self-assembling peptide (SAP) to form a composite DBM/SAP scaffold. By decreasing the pore size and increasing the charge interaction, DBM/SAP scaffolds possess a much higher enriching yield for osteogenic cells and factors compared with DBM alone scaffolds. At the same time, SAP can build a cellular microenvironment for cell adhesion, proliferation, and differentiation that promotes bone reconstruction. As a result, a suitable bone graft fabricated by DBM/SAP scaffolds and bone marrow represents a new strategy and product for bone transplantation in the clinic. PMID:24755526

  4. A composite scaffold of MSC affinity peptide-modified demineralized bone matrix particles and chitosan hydrogel for cartilage regeneration

    Science.gov (United States)

    Meng, Qingyang; Man, Zhentao; Dai, Linghui; Huang, Hongjie; Zhang, Xin; Hu, Xiaoqing; Shao, Zhenxing; Zhu, Jingxian; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Ao, Yingfang

    2015-12-01

    Articular cartilage injury is still a significant challenge because of the poor intrinsic healing potential of cartilage. Stem cell-based tissue engineering is a promising technique for cartilage repair. As cartilage defects are usually irregular in clinical settings, scaffolds with moldability that can fill any shape of cartilage defects and closely integrate with the host cartilage are desirable. In this study, we constructed a composite scaffold combining mesenchymal stem cells (MSCs) E7 affinity peptide-modified demineralized bone matrix (DBM) particles and chitosan (CS) hydrogel for cartilage engineering. This solid-supported composite scaffold exhibited appropriate porosity, which provided a 3D microenvironment that supports cell adhesion and proliferation. Cell proliferation and DNA content analysis indicated that the DBM-E7/CS scaffold promoted better rat bone marrow-derived MSCs (BMMSCs) survival than the CS or DBM/CS groups. Meanwhile, the DBM-E7/CS scaffold increased matrix production and improved chondrogenic differentiation ability of BMMSCs in vitro. Furthermore, after implantation in vivo for four weeks, compared to those in control groups, the regenerated issue in the DBM-E7/CS group exhibited translucent and superior cartilage-like structures, as indicated by gross observation, histological examination, and assessment of matrix staining. Overall, the functional composite scaffold of DBM-E7/CS is a promising option for repairing irregularly shaped cartilage defects.

  5. A composite demineralized bone matrix--self assembling peptide scaffold for enhancing cell and growth factor activity in bone marrow.

    Science.gov (United States)

    Hou, Tianyong; Li, Zhiqiang; Luo, Fei; Xie, Zhao; Wu, Xuehui; Xing, Junchao; Dong, Shiwu; Xu, Jianzhong

    2014-07-01

    The need for suitable bone grafts is high; however, there are limitations to all current graft sources, such as limited availability, the invasive harvest procedure, insufficient osteoinductive properties, poor biocompatibility, ethical problems, and degradation properties. The lack of osteoinductive properties is a common problem. As an allogenic bone graft, demineralized bone matrix (DBM) can overcome issues such as limited sources and comorbidities caused by invasive harvest; however, DBM is not sufficiently osteoinductive. Bone marrow has been known to magnify osteoinductive components for bone reconstruction because it contains osteogenic cells and factors. Mesenchymal stem cells (MSCs) derived from bone marrow are the gold standard for cell seeding in tissue-engineered biomaterials for bone repair, and these cells have demonstrated beneficial effects. However, the associated high cost and the complicated procedures limit the use of tissue-engineered bone constructs. To easily enrich more osteogenic cells and factors to DBM by selective cell retention technology, DBM is modified by a nanoscale self-assembling peptide (SAP) to form a composite DBM/SAP scaffold. By decreasing the pore size and increasing the charge interaction, DBM/SAP scaffolds possess a much higher enriching yield for osteogenic cells and factors compared with DBM alone scaffolds. At the same time, SAP can build a cellular microenvironment for cell adhesion, proliferation, and differentiation that promotes bone reconstruction. As a result, a suitable bone graft fabricated by DBM/SAP scaffolds and bone marrow represents a new strategy and product for bone transplantation in the clinic.

  6. Development of Collagen/Demineralized Bone Powder Scaffolds and Periosteum-Derived Cells for Bone Tissue Engineering Application

    Directory of Open Access Journals (Sweden)

    Wilairat Leeanansaksiri

    2013-01-01

    Full Text Available The aim of this study was to investigate physical and biological properties of collagen (COL and demineralized bone powder (DBP scaffolds for bone tissue engineering. DBP was prepared and divided into three groups, based on various particle sizes: 75–125 µm, 125–250 µm, and 250–500 µm. DBP was homogeneously mixed with type I collagen and three-dimensional scaffolds were constructed, applying chemical crosslinking and lyophilization. Upon culture with human periosteum-derived cells (PD cells, osteogenic differentiation of PD cells was investigated using alkaline phosphatase (ALP activity and calcium assay kits. The physical properties of the COL/DBP scaffolds were obviously different from COL scaffolds, irrespective of the size of DBP. In addition, PD cells cultured with COL scaffolds showed significantly higher cell adhesion and proliferation than those with COL/DBP scaffolds. In contrast, COL/DBP scaffolds exhibited greater osteoinductive potential than COL scaffolds. The PD cells with COL/DBP scaffolds possessed higher ALP activity than those with COL scaffolds. PD cells cultured with COL/DBP scaffolds with 250–500 mm particle size yielded the maximum calcium deposition. In conclusion, PD cells cultured on the scaffolds could exhibit osteoinductive potential. The composite scaffold of COL/DBP with 250–500 mm particle size could be considered a potential bone tissue engineering implant.

  7. Studying the processes of sulphates and chlorides extraction from water at low-waste water demineralization technology

    Directory of Open Access Journals (Sweden)

    Inna M. Тrus

    2014-12-01

    Full Text Available To solve the disposal problem of high-salinity liquid wastes resulting from the water demineralization, researched are the processes of chlorides’ and sulphates’ ion-exchange separation with further sulphates (in the form of calcium sulphate removal from the technological cycle. It is shown that the desulphatized water can be effectively desalinated by reverse osmosis filters, including low-pressure membranes Filmtec TW30-1812-50. The liquid waste obtained in form of concentrates, does contain chlorides, sodium ions and hardness ions. Established is that at these concentrates processing by lime and sodium carbonate or alkali and sodium carbonate they are softened with hardness decrease up to 0,25…0,95 mg-eq/dm3, which allows these solutions’ further electrolysis to obtain alkali and hydrochloric acid. Through direct electrolysis of concentrates, obtained by reverse osmosis water desalination at anionic membrane two-chamber electrolysers, we obtained a disinfectant solution containing chlorine oxigenates (active chlorine, hypochlorite, chlorite and sodium chlorate and duly effective in water sterilization. The resulting solution well keeps its properties and is promising for disinfection of natural and waste waters.

  8. Effect of silver diamine fluoride on remineralization of demineralized dentine in primary teeth in vitro%氟化氨银对乳牙脱矿牙本质体外再矿化的作用

    Institute of Scientific and Technical Information of China (English)

    汤根兄; 李静; 陈银花; 郑红; 周淑; 刘子晗; 龚爱秀

    2015-01-01

    Objective To investigate the effect of silver diamine fluoride on the remineralization of demineralized dentine in vitro .Methods Thirty‐six primary teeth were randomly and equally divided into three groups of A (remineralized with silver diamine fluoride) ,B (remineralized with flouride varnish) and C(control group) .The dentine was analyzed quantificationally by confocal laser scanning microscope .The surface morphology was observed by scanning electron microscope .Results The dentin tubules in group A were completely closed ,which were partly closed in group B and open in group C .The fluorescence area ,total fluorescence intensity and mean fluorescence intensity were lower in groups of A and B than those in group C(P<0 .05) ,which were lower in group A than those in group B ( P<0 .05 ) .Conclusion Silver diamine fluoride and flouride varnish can promote the remineralization of demineralized dentine while the effect of the former was stronger .%目的:研究氟化氨银对乳牙脱矿牙本质体外再矿化的作用。方法36颗离体乳牙,制备牙本质块,形成脱矿牙本质。随机均分为氟化氨银组(A组)、氟保护漆组(B组)和对照组(C组),对脱矿牙本质进行再矿化处理。采用激光扫描共聚焦显微镜对牙本质进行定量分析,扫描电镜观察牙本质表面形态。结果 A组牙本质小管完全封闭,B组部分牙本质小管封闭,C组牙本质小管完全开放。A、B组的脱矿牙本质参数值、牙本质块荧光量面积、总荧光量和病损的平均荧光量均低于C组(P<0.05),A组亦低于B组(P<0.05)。结论氟化氨银和氟保护漆均具有促进脱矿牙本质再矿化的作用,氟化氨银效果更好。

  9. Searching for Critical Slip Surface of Slops Based on Artificial Bee Colony Algorithm%基于人工蜂群算法的边坡最危险滑动面搜索

    Institute of Scientific and Technical Information of China (English)

    康飞; 李俊杰; 马震岳

    2011-01-01

    An artificial bee colony algorithm (ABC) for continuous numerical optisization was introduced into searching for the most dangerous failure surface in slope stability analysis. ABC is a global search algorithm, which models the cooperative foraging process of honeybees, and the disadvantage of being easily trapped into local optima of traditional algorithms may be overcome. To improve the performance of ABC on complex slopes, Hooke-Jeeves pattern search operators were introduced into ABC and a Hooke-Jeeves ABC was proposed for stability analysis of complex slopes. Results of four examples show that the proposed method has higher convergence accuracy and reliability. Thus, a concise effective global strategy is provided for searching the critical slip surface and calculating the minimum factor of safety in slope stability.%将用于连续数值优化问题的人工蜂群算法引入边坡稳定分析临界滑动面搜索领域.该方法模拟了蜂群的群体协作采蜜过程,具有自适应收敛的特点,克服了传统方法容易陷入局部最优的缺点,是一种全局优化算法.为进一步改善其在复杂边坡搜索中的效果,将Hooke-Jeeves模式搜索操作引入人工蜂群算法,提出一种用于边坡临界滑动面搜索的模式搜索人工蜂群算法.对土石坝、海堤等4个实例边坡的计算结果表明,人工蜂群算法是一种简洁、高效的边坡临界滑动面搜索方法;对于复杂边坡,所提出算法具有更高的收敛精度和可靠性,为边坡稳定分析临界滑动面搜索和最小安全系数的计算提供了一种新的全局求解策略.

  10. Artificial intelligence within AFSC

    Science.gov (United States)

    Gersh, Mark A.

    1990-01-01

    Information on artificial intelligence research in the Air Force Systems Command is given in viewgraph form. Specific research that is being conducted at the Rome Air Development Center, the Space Technology Center, the Human Resources Laboratory, the Armstrong Aerospace Medical Research Laboratory, the Armamant Laboratory, and the Wright Research and Development Center is noted.

  11. Artificial Left Ventricle

    CERN Document Server

    Ranjbar, Saeed; Meybodi, Mahmood Emami

    2014-01-01

    This Artificial left ventricle is based on a simple conic assumption shape for left ventricle where its motion is made by attached compressed elastic tubes to its walls which are regarded to electrical points at each nodal .This compressed tubes are playing the role of myofibers in the myocardium of the left ventricle. These elastic tubes have helical shapes and are transacting on these helical bands dynamically. At this invention we give an algorithm of this artificial left ventricle construction that of course the effect of the blood flow in LV is observed with making beneficiary used of sensors to obtain this effecting, something like to lifegates problem. The main problem is to evaluate powers that are interacted between elastic body (left ventricle) and fluid (blood). The main goal of this invention is to show that artificial heart is not just a pump, but mechanical modeling of LV wall and its interaction with blood in it (blood movement modeling) can introduce an artificial heart closed to natural heart...

  12. Artificial Gravity Research Plan

    Science.gov (United States)

    Gilbert, Charlene

    2014-01-01

    This document describes the forward working plan to identify what countermeasure resources are needed for a vehicle with an artificial gravity module (intermittent centrifugation) and what Countermeasure Resources are needed for a rotating transit vehicle (continuous centrifugation) to minimize the effects of microgravity to Mars Exploration crewmembers.

  13. Micromachined Artificial Haircell

    Science.gov (United States)

    Liu, Chang (Inventor); Engel, Jonathan (Inventor); Chen, Nannan (Inventor); Chen, Jack (Inventor)

    2010-01-01

    A micromachined artificial sensor comprises a support coupled to and movable with respect to a substrate. A polymer, high-aspect ratio cilia-like structure is disposed on and extends out-of-plane from the support. A strain detector is disposed with respect to the support to detect movement of the support.

  14. Observations of artificial satellites

    Directory of Open Access Journals (Sweden)

    A. MAMMANO

    1964-06-01

    Full Text Available The following publication gives the results of photographic
    observations of artificial satellites made at Asiago during the second
    and third year of this programme. The fixed camera technique and that
    with moving film (the latter still in its experimental stage have been used.

  15. Introduction to Artificial Neural Networks

    DEFF Research Database (Denmark)

    Larsen, Jan

    1999-01-01

    The note addresses introduction to signal analysis and classification based on artificial feed-forward neural networks.......The note addresses introduction to signal analysis and classification based on artificial feed-forward neural networks....

  16. 酪蛋白磷酸多肽-无定形磷酸钙对固定正畸所致牙釉质脱矿的影响%The Influence of Casein Phospho Peptides-Amorphous Calcium Phosphate on Enamel Demineralization Induced by Fixed Orthodontic

    Institute of Scientific and Technical Information of China (English)

    李宇; 唐璐; 杨四维; 庞兰

    2015-01-01

    Objective:To study the influence of casein phospho peptides -amorphous calcium phosphate ( Casein phosphopeptide-amorphic calcium phosphate, CPP-ACP, the product name of GC Tooth Mousse) on enamel demineralization as fixed orthodontic.Methods:40 patients with fixed orthodontic treatment were randomly divided into a control group A group and experimental group B,each group of 20.GroupA had a simple oral hygiene measure on the basis of health education, group B had GC Tooth Mousse on the basis ofgroup A.From the start of treatment to 13-month, observed teeth photograph on two groups, observed whether there were emergine piece of chalk stain or cavities on teeth surface.Analysed by statistics and calculated the rate of enamel demineralization and demineralization Index(EDI).Results:(1)The enamel demineralization rate was increases in both group A and group B with time passing;( 2 ) EDI of group A was higher than that in group B, there was a statistically significant.Conclusion:The use of CPP-ACP of containing GC Tooth Mousse on the basis of oral hygiene measures in preventing enamel demineralization are safe and effective measure.%目的:研究酪蛋白磷酸多肽-无定形磷酸钙(商品名GC护牙素)对固定正畸所致牙釉质脱矿的影响。方法:选择固定正畸治疗患者40例,经签字同意进入实验。以随机数字表法随机分为对照组、实验组各20例。对照组在口腔卫生宣教的基础上采用单纯口腔卫生措施,实验组在对照组的基础上使用GC护牙素。2组患者从治疗开始,进行连续13个月的牙照片观察。观测指标为牙面是否有新出现的的白垩色斑片或龋洞,统计并计算牙釉质脱矿率及脱矿指数(EDI)。结果:(1)对照组、实验组的牙釉质脱矿率均随着时间的增加而增高;(2)对照组EDI高于实验组。结论:在口腔卫生措施的基础上使用GC护牙素预防固定正畸所致牙釉质脱矿是一种安全有效的措施。

  17. The Influence of Casein Phospho Peptides-Amorphous Calcium Phosphate on Enamel Demineralization Induced by Fixed Orthodontic%酪蛋白磷酸多肽-无定形磷酸钙对固定正畸所致牙釉质脱矿的影响

    Institute of Scientific and Technical Information of China (English)

    李宇; 唐璐; 杨四维; 庞兰

    2015-01-01

    目的:研究酪蛋白磷酸多肽-无定形磷酸钙(商品名GC护牙素)对固定正畸所致牙釉质脱矿的影响。方法:选择固定正畸治疗患者40例,经签字同意进入实验。以随机数字表法随机分为对照组、实验组各20例。对照组在口腔卫生宣教的基础上采用单纯口腔卫生措施,实验组在对照组的基础上使用GC护牙素。2组患者从治疗开始,进行连续13个月的牙照片观察。观测指标为牙面是否有新出现的的白垩色斑片或龋洞,统计并计算牙釉质脱矿率及脱矿指数(EDI)。结果:(1)对照组、实验组的牙釉质脱矿率均随着时间的增加而增高;(2)对照组EDI高于实验组。结论:在口腔卫生措施的基础上使用GC护牙素预防固定正畸所致牙釉质脱矿是一种安全有效的措施。%Objective:To study the influence of casein phospho peptides -amorphous calcium phosphate ( Casein phosphopeptide-amorphic calcium phosphate, CPP-ACP, the product name of GC Tooth Mousse) on enamel demineralization as fixed orthodontic.Methods:40 patients with fixed orthodontic treatment were randomly divided into a control group A group and experimental group B,each group of 20.GroupA had a simple oral hygiene measure on the basis of health education, group B had GC Tooth Mousse on the basis ofgroup A.From the start of treatment to 13-month, observed teeth photograph on two groups, observed whether there were emergine piece of chalk stain or cavities on teeth surface.Analysed by statistics and calculated the rate of enamel demineralization and demineralization Index(EDI).Results:(1)The enamel demineralization rate was increases in both group A and group B with time passing;( 2 ) EDI of group A was higher than that in group B, there was a statistically significant.Conclusion:The use of CPP-ACP of containing GC Tooth Mousse on the basis of oral hygiene measures in preventing enamel demineralization are safe and

  18. Radiographic display of carious lesions and cavitation in approximal surfaces

    DEFF Research Database (Denmark)

    Wenzel, Ann

    2014-01-01

    Abstract Background. Treatment strategies have changed with efforts on arresting carious lesions suspected to have an intact surface sparing operative treatment for cavitated lesions. Radiography is still the most recommended adjunct method in the diagnosis of clinically inaccessible approximal...... surfaces. Bitewing radiography. The major drawback of bitewing radiography for caries diagnosis is that the clinical state of the surface cannot be determined; i.e. if cavitation has developed or the demineralized surface is still intact. Based on studies of the relationship between radiographic lesion...

  19. Artificial tears potpourri: a literature review

    Directory of Open Access Journals (Sweden)

    Moshirfar M

    2014-07-01

    Full Text Available Majid Moshirfar,1 Kasey Pierson,2,* Kamalani Hanamaikai,3,* Luis Santiago-Caban,1 Valliammai Muthappan,1 Samuel F Passi11Department of Ophthalmology, John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA; 2University of Arizona College of Medicine, Phoenix, Phoenix, AZ, USA; 3A T Still University, School of Osteopathic Medicine in Arizona, Mesa, AZ, USA *These authors contributed equally to this work Abstract: Numerous brands and types of artificial tears are available on the market for the treatment of dysfunctional tear syndrome. Past literature has focused on comparing the components of these products on patient’s clinical improvement. The wide array of products on the market presents challenges to both clinicians and patients when trying to choose between available tear replacement therapies. Different formulations affect patients based on etiology and severity of disease. In order to provide an unbiased comparison between available tear replacement therapies, we conducted a literature review of existing studies and National Institutes of Health clinical trials on commercially available, brand name artificial tears. Outcomes evaluated in each study, as well as the percent of patients showing clinical and symptomatic improvement, were analyzed. Fifty-one studies evaluating different brands of artificial tears, and their efficacy were identified. Out of the 51 studies, 18 were comparison studies testing brand name artificial tears directly against each other. Nearly all formulations of artificial tears provided significant benefit to patients with dysfunctional tear syndrome, but some proved superior to others. From the study data, a recommended treatment flowchart was derived. Keywords: dry eye, tear film, dysfunctional tear syndrome, ophthalmic lubricant, artificial tears, lipid layer, tear osmolarity, TBUT, Systane®, Refresh®, Blink®, GenTeal®, Soothe®, Lacrisert®, ocular surface inflammatory disease, Sjogren

  20. In vitro study of demineralization resistance and fluoride retention in dental enamel irradiated with Er,Cr: YSGG laser; Estudo in vitro da resistencia a desmineralizacao e da retencao de fluor em esmalte dental irradiado com laser de Er, Cr: YSGG

    Energy Technology Data Exchange (ETDEWEB)

    Ana, Patricia Aparecida da. E-mail: patriciadaana@yahoo.com.br

    2007-07-01

    This study aimed to establish irradiation conditions of Er,Cr:YSGG laser ({lambda} of 2.79 {mu}m) which could propitiate changes on human dental enamel and increase its resistance to demineralization, when associated or not with topical application of acidulated phosphate fluoride (APF). Fluences of 2,8 J/cm{sup 2}, 5,6 J/cm{sup 2} e 8,5 J/cm{sup 2} were selected; they were associated or not with previous application of a photo absorber (coal paste) and then APF was applied or not after laser irradiation. In a first step, the morphological findings, the surface temperatures, and the pupal temperatures were evaluated during laser irradiation. After that, the treated samples were submitted to a a ten-day pH-cycling model. After producing the incipient white-spots lesions, the following aspects were evaluated: the mineral loss, the loosely bound fluoride and the firmly bound fluoride. All the demineralizing and remineralizing pH-cycling solutions were evaluated with respect to their calcium (Ca), inorganic phosphorous (Pi) and fluoride (F{sup -}) concentrations. The data had their normality and homogeneity distribution statistically evaluated, and it was chosen an appropriated statistical test for each performed analysis according to the obtained results, considering 5% significant level. The fluences selected for this study created ablated surfaces; the fluences of 5.6 J/cm{sup 2} and 8.5 J/cm{sup 2} promoted increments in surface temperature above 110 deg C. The intrapupal temperature changes revealed that laser irradiation did not increase the pulpal temperatures above the critical threshold for induction of pulpitis. The coal paste did not promote any changes on surface morphology or in the intrapulpal temperature changes; however, this paste increased the surface temperatures during laser irradiation. Only laser irradiation at 8.5 J/cm{sup 2} was able to decrease the mineral loss when compared to the no-treatment group; although the association of coal paste

  1. Effects of Saliva and Topical Fluoride Application on Enamel of Young Permanent Teeth Demineralized by Carbonated Beverage%唾液及氟化物对碳酸饮料导致年轻恒牙釉质脱矿的影响

    Institute of Scientific and Technical Information of China (English)

    周娟; 许明莲; 杜姗姗; 胡孝丽; 罗志晓; 柴红波; 朱友家

    2013-01-01

    Objective To explore the remineralization of young permanent teeth demineralized by carbonated beverage with human saliva and topical fluoride application. Methods Thirty young permanent premolar were collected from orthodontic extraction and immersed in carbonated beverage for one week,then they were randomly divided into group A,B and C(n = 10). All teeth were cleaned with distilled water,and then put into normal human saliva,0.1% NaF solution and toothpaste with fluoride for one month,respectively. The morphology changes of enamel surface were observed by scanning electron microscope, and the results was analyzed. Results The enamel surface of group A showed uneven distribution of the mineral particle,which was cloudy covering in the lacunae making the aperture smaller and the depth shallower;the enamel surface of group B showed discrete and irregular settlings with piece or mass form covering in the lacunae, making the depth shallower; the enamel surface of group C showed flat,the depth of demineralization area was superficial,there was some compact and irregular settlings, the degree of demineralization of axon cylinder was obviously reduced, and the density of good mineralization position was close to normal enamel. Conclusion After demineralizing young permanent teeth with carbonated beverage, the remineralization could occur in oral environment within limited degree. The application of fluoride in enamel surface can promote the remineralization.%目的:探讨碳酸饮料处理过的年轻恒牙分别在正常人体唾液中,和经氟化物处理后,牙釉质的再矿化情况.方法:收集因正畸减数拔除的年轻恒前磨牙30颗,置入碳酸饮料中浸泡1周后,将其随机分为3组,用蒸馏水洗净后,分别置入正常人体唾液(A组)、0.1% NaF溶液(B组)及含氟牙膏(C组)中1个月,应用扫描电镜观察各组牙齿牙釉质表面的形态学变化,并对影像结果进行对比分析.结果:A组牙齿的釉质表面有分布不

  2. Multivariate analysis of surface physico-chemical properties controlling biofilm formation on orthodontic adhesives prior to and after fluoride and chlorhexidine treatment

    NARCIS (Netherlands)

    Chin, Yeen; Sandham, John; Pratten, Jonathan; de Vries, Jacob; van der Mei, Henny C.; Busscher, Henk J.

    2006-01-01

    Biofilm formation on orthodontic adhesives is a serious clinical problem, as it leads to enamel demineralization around fixed orthodontic appliances, often leaving white spot lesions after their removal. The aim of this work was to determine the influence of surface physico-chemical properties of fo

  3. Electrolyte-promoted demineralization of biogenic, vitreous, and crystalline silica: A density functional investigation

    Science.gov (United States)

    Dove, P. M.; Wallace, A. F.; Gibbs, G. V.

    2007-12-01

    The dissolution of amorphous and crystalline varieties of SiO2 is an integral part of the global biogeochemical cycle of silicon. Nanoparticulate biogenic silica produced by marine phytoplankton and terrestrial plants are of particular interest because their enhanced reactivity and abundance make them important sources and sinks of dissolved silicon in natural environments. Recent experimental results on (100) surfaces of quartz show that the dominant dissolution mechanism in simple H2O solutions is by retreat of Q2 groups along step edges. In the presence of electrolytes, rates are accelerated by up to 100X in the presence by a crossover in the dominant dissolution mechanism to nucleation of vacancy islands at Q3 terminated species (Dove et al., PNAS, 2005). While the control of surface coordination in reactivity is clear, the molecular pathway by which electrolytes induce dissolution by a nucleated process remains poorly understood. The results of previous ab initio investigations of Si-O bond hydrolysis by water have demonstrated that the reaction proceeds through the dissociative adsorption of H2O at the silica surface, resulting in the formation of a pentacoordinated Si transition state, followed by the transfer of one of the water bound hydrogen atoms to a bridging oxygen in the SiO2 bonded network, and breakage of the Si-O bond. Assuming a similar reaction path, the specific effects of hydrated group II metal cations (Mg2+, Ca2+, Sr2+, Ba2+) on the energetics of Si-O bond hydrolysis have been investigated with density functional methods (B3LYP) and a relatively large neutral silica cluster (H8Si6O16). Reactant, product, and transition states for Q3 to Q2 hydrolysis in the presence and absence of the afore-mentioned cations have been determined with all electron (6-31G(d)) and effective core potential (SDDALL) Gaussian basis sets. The free energy of activation for Q3 to Q2 Si-O bond hydrolysis was determined to be approximately 5 kJ/mol lower for Ca2+ than Mg

  4. Evaluation of inactivation of intracanal antiseptics by dentin, demineralized dentin, dentin matrix and mineral component of dentin

    Directory of Open Access Journals (Sweden)

    Razmi H

    2007-01-01

    Full Text Available Background and Aim: Many studies have shown that microorganisms are the main cause of pulpal diseases and the main purpose of root canal therapy is their elimination from the root canal system. Antiseptic agents are used to reduce bacteria but their antibacterial activities differ from in vivo to in vitro studies and might be inactivated by dentin and its components in root canal space. This study was designed to investigate the effect of dentin on antibacterial activity of different antimicrobial agents. Materials and Methods: In this experimental study, two antibacterial agents (sodium hypochlorite and chlorhexidine with different concentrations were used in four experimental groups: Group 1: dentin, Group 2: demineralized dentin with EDTA, Group 3: dentin matrix and Group 4: dentin mineral component. The species used in this study was Entrococcus faecalis. Different concentration of agents were added to mixture of each experimental group and bacteria. At the baseline and after one and 24 hours, samples were collected and cultured. After incubation period, colonies were counted. Data were analyzed by Tukey test with p<0.05 as the limit of significance. Results: 2% and 0.2% chlorhexidine, and 5% sodium hypochlorite solutions at the three studied times eliminated Entrococcus faecalis completely. 1% sodium hypochlorite eliminated all bacteria in 1h and 24 hs. Statistical analysis showed significant differences between experimental and control groups (P<0.05. Sodium 1% hypochlorite at time 0, could reduce bacteria significantly (P<0.05 but didn’t eliminate them completely. Conclusion: Inactivation of intracanal antiseptics was not observed in this study. As elimination of bacteria occurred, application of these antibacterial agents are recommended in endodontic treatment. Further investigations on other antibacterial agents, other concentrations and shorter time intervals are recommended.

  5. Transplantation of allogenic chondrocytes with chitosan hydrogel-demineralized bone matrix hybrid scaffold to repair rabbit cartilage injury.

    Science.gov (United States)

    Man, Zhentao; Hu, Xiaoqing; Liu, Zhenlong; Huang, Hongjie; Meng, Qingyang; Zhang, Xin; Dai, Linghui; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Zhou, Chunyan; Ao, Yingfang

    2016-11-01

    Cartilage tissue engineering is the hotspot of cartilage repair. The allogenic chondrocytes appear to be a promising source of seed cells in cartilage tissue engineering. In this study, we aimed to transplant allogenic chondrocytes with chitosan hydrogel (CS)-demineralized bone matrix (DBM) hybrid scaffold (CS/DBM) to repair rabbit cartilage injury with one-step operation. After the CS/DBM scaffold was successfully fabricated, it showed that the porous CS filled the large pores of DBM, which improved the distribution of seed cells in the CS/DBM scaffold. The allogenic chondrocytes at second passage were transplanted with different scaffolds to repair rabbit cartilage injury. Twenty-four weeks after surgery, the cartilage defect in the CS/DBM group was successfully filled as shown by MRI. Moreover, the histological score of CS/DBM group was significantly higher than that of the other groups. On the aspect of biomechanical property, the regenerated cartilage in the CS/DBM group were superior to those in the other groups as determined by nanoindentation. Meanwhile, no obvious inflammatory response was observed after the transplantation of allogenic chondrocytes at 24 weeks post-surgery. Furtherly, gene expression profile for cells within the repair tissue was compared with the allogenic chondrocytes before transplantation using Agilent microarray and RT-qPCR. The results showed that some genes beneficial to cartilage regeneration, such as BMP-7, HGF, and IGF-1, were upregulated one month after transplantation. Consequently, our study demonstrated that the transplantation of allogenic chondrocytes with CS/DBM scaffold successfully repaired rabbit cartilage injury with only one-step operation, thereby providing new insights into cartilage tissue engineering. PMID:27636153

  6. Determination of orthodontic tooth movement and tissue reaction following demineralized freeze-dried bone allograft grafting intervention

    Directory of Open Access Journals (Sweden)

    Massoud Seifi

    2012-01-01

    Full Text Available Background: Socket preservation after tooth extraction is one of the indications of bone grafting to enhance preorthodontic condition. The aim of this study is to determine the effects of socket preservation on the immediate tooth movement, alveolar ridge height preservation and orthodontic root resorption. Materials and Methods: In a split-mouth technique, twelve sites in three dogs were investigated as an experimental study. Crushed demineralized freeze-dried bone allograft (DFDBA (CenoBone® was used as the graft material. The defects were made by the extraction of 3 rd premolar. On one side of each jaw, the defects were preserved by DFDBA and defects of the other side left opened as the control group. Simultaneously the teeth adjacent to the defects were pulled together by a NiTi coil spring. After eight weeks, the amount of (OTM, alveolar height, and root resorption were measured. Analysis of variance was used for purpose of comparison. Results: There was a slight increase in OTM at grafted sites as they were compared to the control sites (P<0.05. Also a significant bone resorption in control site and successful socket preservation in experimental site were observed. Reduction of root resorption at the augmented site was significant compared to the normal healing site (P<0.05. Conclusion: Using socket preservation, tooth movement can be immediately started without waiting for the healing of the recipient site. This can provide some advantages like enhanced rate of OTM, its approved effects on ridge preservation that reduces the chance of dehiscence and the reduction of root resorption.

  7. Artificial organisms that sleep.

    OpenAIRE

    Mirolli, Marco; Parisi, Domenico

    2003-01-01

    Abstract Populations of artificial organisms live in an environment in which light is cyclically present (day) or absent (night). Since being active during night is non-adaptive (activity consumes energy which is not compensated by the food found at night) the organisms evolve a sleep/wake behavioral pattern of being active during daytime and sleeping during nighttime. When the population moves to a different environment that contains "caves", they have to get out of a cave although the dark ...

  8. Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Kapil Nahar

    2012-12-01

    Full Text Available An artificial neural network is an information-processing paradigm that is inspired by the way biological nervous systems, such as the brain, process information. The key element of this paradigm is the novel structure of the information processing system. It is composed of a large number of highly interconnected processing elements (neurons working in unison to solve specific problems. Ann’s, like people, learn by example.

  9. Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Kapil Nahar

    2012-12-01

    Full Text Available An artificial neural network is an information-processing paradigm that is inspired by the way biological nervous systems, such as the brain, process information.The key element of this paradigm is the novel structure of the information processing system. It is composed of a large number of highly interconnected processing elements (neurons working in unison to solve specific problems.Ann’s, like people, learn by example.

  10. Artificial neural network modelling

    CERN Document Server

    Samarasinghe, Sandhya

    2016-01-01

    This book covers theoretical aspects as well as recent innovative applications of Artificial Neural networks (ANNs) in natural, environmental, biological, social, industrial and automated systems. It presents recent results of ANNs in modelling small, large and complex systems under three categories, namely, 1) Networks, Structure Optimisation, Robustness and Stochasticity 2) Advances in Modelling Biological and Environmental Systems and 3) Advances in Modelling Social and Economic Systems. The book aims at serving undergraduates, postgraduates and researchers in ANN computational modelling. .

  11. Artificial sweetener; Jinko kanmiryo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-08-01

    The patents related to the artificial sweetener that it is introduced to the public in 3 years from 1996 until 1998 are 115 cases. The sugar quality which makes an oligosaccharide and sugar alcohol the subject is greatly over 28 cases of the non-sugar quality in the one by the kind as a general tendency of these patents at 73 cases in such cases as the Aspartame. The method of manufacture patent, which included new material around other peptides, the oligosaccharide and sugar alcohol isn`t inferior to 56 cases of the formation thing patent at 43 cases, and pays attention to the thing, which is many by the method of manufacture, formation. There is most improvement of the quality of sweetness with 31 cases in badness of the aftertaste which is characteristic of the artificial sweetener and so on, and much stability including the improvement in the flavor of food by the artificial sweetener, a long time and dissolution, fluid nature and productivity and improvement of the economy such as a cost are seen with effect on a purpose. (NEDO)

  12. Morphology and thickness of the diffusion of resin through demineralized or unconditioned dentinal matrix

    Directory of Open Access Journals (Sweden)

    Arrais César Augusto Galvão

    2002-01-01

    Full Text Available The formation of a hybrid layer is the main bonding mechanism of current dentin-bonding systems. This study evaluated the morphology and thickness of the resin-infiltrated dentinal layer after the application of adhesive systems. The dentin-bonding agents were evaluated on flat dentinal preparations confected on the occlusal surfaces of human teeth. The test specimens were prepared and inspected under scanning electron microscopy at a magnification of X 2,000. The adhesive systems were responsible for different hybrid layer thicknesses (p < 0.05, and the mean values were: for Scotchbond MP Plus (SM, 7.41 ± 1.24mum; for Single Bond (SB, 5.55 ± 0.82mum; for Etch & Prime 3.0 (EP, 3.86 ± 1.17mum; and for Clearfil SE Bond (CB, 1.22 ± 0.45mum. The results suggest that the conventional three-step adhesive system (SM was responsible for the thickest hybrid layer, followed by the one-bottle adhesive (SB. The self-etching adhesives, EP and CB, produced the formation of the thinnest hybrid layers.

  13. Effects of 960 nm diode laser irradiation on dental enamel in vitro: temperature and morphological analysis and evaluation of enamel demineralization

    International Nuclear Information System (INIS)

    The aim of this study is to determine the effects of diode laser irradiation on enamel demineralization. To achieve this goal appropriate photon absorbing substances for the laser radiation, safe laser parameters and adequate temperature measuring apparatus had to be determined. Next, the effects of diode laser and acidulated phosphate fluoride on enamel demineralization by calcium content analysis were evaluated with inductively coupled plasma atomic emission spectrometry (ICP-AES). In the first part of the study, five dyes consisting of vegetable coal diluted in five different liquids were analyzed and vegetable coal diluted in physiological solution was chosen for use as absorber. Methodologies to measure pulp chamber temperature were evaluated and modeling clay was chosen as fixture for the enamel samples held at body temperature. In the second part of the study, different energy density parameters (1.8 J/cm2, 3.7 J/cm2, 5.6 J/cm2, 7.4 J/cm2 and 9.3 J/cm2) exposure times (10, 15, 20, 25 e 30 seconds) and time intervals between dye application and laser irradiation (5, 30, 60, 90 e 120 seconds) were evaluated with respect to temperature changes in the pulp chamber. The enamel morphology was analyzed by scanning electron microscopy. Acid resistance was measured using seventy five enamel specimens, divided in five groups (control, fluoride, laser, laser + fluoride and fluoride + laser). The amount of calcium lost during demineralization in lactic acid was measured by ICP-AES. The results obtained in this experiment permit the conclusion that diode laser irradiation did not increase acid resistance. When associated with fluoride, the acid resistance did not differ from the results obtained with fluoride alone. (author)

  14. Mitigating ground clutter effects with lightweight artificial dielectrics

    Science.gov (United States)

    Rappaport, Carey M.; Beihold, Fred; Linnehan, Robert

    2001-10-01

    The problem of scattered and transmitted electromagnetic wave distortion by random rough ground surfaces can be reduced by using a lightweight dielectric matching layer. For mine detection applications, it is essential for this layer to be lightweight, low loss, readily conformable, and adaptable to different soil types. Arrays of metal-coated plastic spheres act as lossless artificial dielectrics with impedance determined by the volume packing fraction. By controlling the thickness of insulator surrounding each sphere, a close-packed array with the dielectric properties of soil can be created inside a compliant rolling bag that will conform to the rough surface of the ground. Since this artificial dielectric is matched to the soil, the ground surface interface is 'softened', without an abrupt transition from soil to air. Signals transmitted and received by GPR antennas immersed in the artificial dielectric within the bag will not be corrupted by ground surface clutter. Alternatively, an artificial dielectric layer on the ground with a planar air interface could be used to ensure that the surface reflection is a constant, well-calibrated signal. Computational models indicate complete removal of the ground clutter, even with occasional gaps between the artificial dielectric and the ground. Experimental studies with swept-frequency measurements and impulse GPR indicate that using this dielectric layer matching to a rough loamy soil ground surface is results in signals that are practically indistinguishable from those of an equivalent layer of the same type of soil.

  15. ENGINEERING ECONOMIC ANALYSIS OF A PROGRAM FOR ARTIFICIAL GROUNDWATER RECHARGE.

    Science.gov (United States)

    Reichard, Eric G.; Bredehoeft, John D.

    1984-01-01

    This study describes and demonstrates two alternate methods for evaluating the relative costs and benefits of artificial groundwater recharge using percolation ponds. The first analysis considers the benefits to be the reduction of pumping lifts and land subsidence; the second considers benefits as the alternative costs of a comparable surface delivery system. Example computations are carried out for an existing artificial recharge program in Santa Clara Valley in California. A computer groundwater model is used to estimate both the average long term and the drought period effects of artificial recharge in the study area. Results indicate that the costs of artificial recharge are considerably smaller than the alternative costs of an equivalent surface system. Refs.

  16. Artificial Hair Cells for Sensing Flows

    Science.gov (United States)

    Chen, Jack

    2007-01-01

    The purpose of this article is to present additional information about the flow-velocity sensors described briefly in the immediately preceding article. As noted therein, these sensors can be characterized as artificial hair cells that implement an approximation of the sensory principle of flow-sensing cilia of fish: A cilium is bent by an amount proportional to the flow to which it is exposed. A nerve cell at the base of the cilium senses the flow by sensing the bending of the cilium. In an artificial hair cell, the artificial cilium is a microscopic cantilever beam, and the bending of an artificial cilium is measured by means of a strain gauge at its base (see Figure 1). Figure 2 presents cross sections of a representative sensor of this type at two different stages of its fabrication process. The process consists of relatively- low-temperature metallization, polymer-deposition, microfabrication, and surface-micromachining subprocesses, including plastic-deformation magnetic assembly (PDMA), which is described below. These subprocesses are suitable for a variety of substrate materials, including silicon, some glasses, and some polymers. Moreover, because it incorporates a polymeric supporting structure, this sensor is more robust, relative to its silicon-based counterparts.

  17. Mechanism of artificial heart

    CERN Document Server

    Yamane, Takashi

    2016-01-01

    This book first describes medical devices in relation to regenerative medicine before turning to a more specific topic: artificial heart technologies. Not only the pump mechanisms but also the bearing, motor mechanisms, and materials are described, including expert information. Design methods are described to enhance hemocompatibility: main concerns are reduction of blood cell damage and protein break, as well as prevention of blood clotting. Regulatory science from R&D to clinical trials is also discussed to verify the safety and efficacy of the devices.

  18. Polymer artificial muscles

    Directory of Open Access Journals (Sweden)

    Tissaphern Mirfakhrai

    2007-04-01

    Full Text Available The various types of natural muscle are incredible material systems that enable the production of large deformations by repetitive molecular motions. Polymer artificial muscle technologies are being developed that produce similar strains and higher stresses using electrostatic forces, electrostriction, ion insertion, and molecular conformational changes. Materials used include elastomers, conducting polymers, ionically conducting polymers, and carbon nanotubes. The mechanisms, performance, and remaining challenges associated with these technologies are described. Initial applications are being developed, but further work by the materials community should help make these technologies applicable in a wide range of devices where muscle-like motion is desirable.

  19. Uncertainty in artificial intelligence

    CERN Document Server

    Kanal, LN

    1986-01-01

    How to deal with uncertainty is a subject of much controversy in Artificial Intelligence. This volume brings together a wide range of perspectives on uncertainty, many of the contributors being the principal proponents in the controversy.Some of the notable issues which emerge from these papers revolve around an interval-based calculus of uncertainty, the Dempster-Shafer Theory, and probability as the best numeric model for uncertainty. There remain strong dissenting opinions not only about probability but even about the utility of any numeric method in this context.

  20. Bayesian artificial intelligence

    CERN Document Server

    Korb, Kevin B

    2010-01-01

    Updated and expanded, Bayesian Artificial Intelligence, Second Edition provides a practical and accessible introduction to the main concepts, foundation, and applications of Bayesian networks. It focuses on both the causal discovery of networks and Bayesian inference procedures. Adopting a causal interpretation of Bayesian networks, the authors discuss the use of Bayesian networks for causal modeling. They also draw on their own applied research to illustrate various applications of the technology.New to the Second EditionNew chapter on Bayesian network classifiersNew section on object-oriente

  1. Growth Kinetics and Demineralization of Shrimp Shell Using L a c t o b a c i l l u s p l a n t a r u m PTCC 1058 on Various Carbon Sources

    Directory of Open Access Journals (Sweden)

    M. Khorrami

    2011-09-01

    Full Text Available The present study has focused on the effect of various carbon sources such as glucose, sucrose and date syrup as natural carbon sources along with Lactobacillus plantarum microorganism on demineralization (DM of shrimp shell. Logistic and Verhulst Equations were used for the determination of growth kinetic parameters. Maximum demineralization efficiency of 82% was obtained in the media contained date syrup. Data for fermentation with media contained date syrup were suitably fitted with both Verhulst and Logistic Equations. Kinetic data was obtained and Gompertz model for production of lactic acid was used. For the media contained date syrup as carbon source, maximum rate of acid production was obtained.

  2. How to teach artificial organs.

    Science.gov (United States)

    Zapanta, Conrad M; Borovetz, Harvey S; Lysaght, Michael J; Manning, Keefe B

    2011-01-01

    Artificial organs education is often an overlooked field for many bioengineering and biomedical engineering students. The purpose of this article is to describe three different approaches to teaching artificial organs. This article can serve as a reference for those who wish to offer a similar course at their own institutions or incorporate these ideas into existing courses. Artificial organ classes typically fulfill several ABET (Accreditation Board for Engineering and Technology) criteria, including those specific to bioengineering and biomedical engineering programs.

  3. Development of artificial empathy.

    Science.gov (United States)

    Asada, Minoru

    2015-01-01

    We have been advocating cognitive developmental robotics to obtain new insight into the development of human cognitive functions by utilizing synthetic and constructive approaches. Among the different emotional functions, empathy is difficult to model, but essential for robots to be social agents in our society. In my previous review on artificial empathy (Asada, 2014b), I proposed a conceptual model for empathy development beginning with emotional contagion to envy/schadenfreude along with self/other differentiation. In this article, the focus is on two aspects of this developmental process, emotional contagion in relation to motor mimicry, and cognitive/affective aspects of the empathy. It begins with a summary of the previous review (Asada, 2014b) and an introduction to affective developmental robotics as a part of cognitive developmental robotics focusing on the affective aspects. This is followed by a review and discussion on several approaches for two focused aspects of affective developmental robotics. Finally, future issues involved in the development of a more authentic form of artificial empathy are discussed.

  4. A comparative evaluation of extraction socket preservation with demineralized freeze-dried bone allograft alone and along with platelet-rich fibrin: A clinical and radiographic study

    Directory of Open Access Journals (Sweden)

    Dhaval J Thakkar

    2016-01-01

    Full Text Available Aims: To investigate clinically and radiographically, the bone fill in extraction sockets using demineralized freeze-dried bone allograft alone and along with platelet-rich fibrin (PRF. Materials and Methods: A randomized controlled clinical trial was carried out on 36 nonrestorable single-rooted teeth sites. Sites were randomized into demineralized freeze-dried bone allograft (DFDBA combined with PRF - test and DFDBA - control groups using a coin toss method. After the placement of graft material, collagen membrane was used to cover it. The clinical parameters recorded were ridge width and ridge height. All the parameters were recorded at baseline and at 90 and 180 days. Statistical Analysis Used: Independent t-test and paired t-test. Results: In both groups, there is significant reduction in loss of ridge width and ridge height from baseline to 90 days (P < 0.001, baseline to 180 days (P < 0.001, and 90-180 days (P < 0.001. However, when both the groups were compared the test group favored in the reduction of ridge width while there was no statistical difference in reduction of ridge height among at different intervals. Conclusions: Although DFDBA is considered as an ideal graft material, PRF can be used as an adjunctive with DFDBA for socket preservation.

  5. 纳滤膜在乳清脱盐中的应用研究%Application of nanofiltration membrane in whey demineralization

    Institute of Scientific and Technical Information of China (English)

    宋齐; 潘凯; 曹兵

    2011-01-01

    Using the TFC-SR2 spiral nanofiltration membrane, whey was acidified at different pH to measure the effect of desalination. The ash of dry condensed product in different feed conditions was measured.Results indicated that the best condition for demineralization was achieved for the isoelectric point of Whey protein (pH=4.60). And at pH 4.60 with diafiltration of 1.3 MPa, higher demineralization was gotten.%实验通过调节乳清的pH值,利用TFC-SR2卷式纳滤膜对乳清进行脱盐研究,对在不同pH值状态下的乳清浓缩液干物进行灰分的测定.实验结果表明,当调整pH值为乳清蛋白的等电点4.6时,浓缩液干物灰分含量最少,脱盐效果最好.在乳清液pH值为4.6,操作压力为1.3 MPa时,进行了渗透循环操作,得到了更好的脱盐效果.

  6. Generative Artificial Intelligence : Philosophy and Theory of Artificial Intelligence

    NARCIS (Netherlands)

    van der Zant, Tijn; Kouw, Matthijs; Schomaker, Lambertus; Mueller, Vincent C.

    2013-01-01

    The closed systems of contemporary Artificial Intelligence do not seem to lead to intelligent machines in the near future. What is needed are open-ended systems with non-linear properties in order to create interesting properties for the scaffolding of an artificial mind. Using post-structuralistic

  7. Assessing Landslide Hazard Using Artificial Neural Network

    DEFF Research Database (Denmark)

    Farrokhzad, Farzad; Choobbasti, Asskar Janalizadeh; Barari, Amin;

    2011-01-01

    neural network has been developed for use in the stability evaluation of slopes under various geological conditions and engineering requirements. The Artificial neural network model of this research uses slope characteristics as input and leads to the output in form of the probability of failure...... and factor of safety. It can be stated that the trained neural networks are capable of predicting the stability of slopes and safety factor of landslide hazard in study area with an acceptable level of confidence. Landslide hazard analysis and mapping can provide useful information for catastrophic loss...... failure" which is main concentration of the current research and "liquefaction failure". Shear failures along shear planes occur when the shear stress along the sliding surfaces exceed the effective shear strength. These slides have been referred to as landslide. An expert system based on artificial...

  8. Artificial organs: recent progress in artificial hearing and vision.

    Science.gov (United States)

    Ifukube, Tohru

    2009-01-01

    Artificial sensory organs are a prosthetic means of sending visual or auditory information to the brain by electrical stimulation of the optic or auditory nerves to assist visually impaired or hearing-impaired people. However, clinical application of artificial sensory organs, except for cochlear implants, is still a trial-and-error process. This is because how and where the information transmitted to the brain is processed is still unknown, and also because changes in brain function (plasticity) remain unknown, even though brain plasticity plays an important role in meaningful interpretation of new sensory stimuli. This article discusses some basic unresolved issues and potential solutions in the development of artificial sensory organs such as cochlear implants, brainstem implants, artificial vision, and artificial retinas. PMID:19330498

  9. Effect of Minqing Ao dental desensitizer on the demineralization of primary teeth enamel%奥敏清牙齿脱敏剂对脱矿乳牙釉质作用的研究

    Institute of Scientific and Technical Information of China (English)

    俞少玲; 李姮; 王文梅

    2015-01-01

    目的:研究局部应用奥敏清牙齿脱敏剂对可乐酸蚀脱矿乳牙釉质再矿化的作用。方法:收集临床因滞留拔除的健康乳磨牙30颗,将每颗牙沿颊舌向和近远中向纵切成4个牙块,随机进入A、B、C、D组(n=30)。经碳酸饮料浸泡脱矿(10 min×10次/d×7 d)后,进行如下处理:A组(不处理)、B组(奥敏清牙齿脱敏剂处理)、C组(氟化物处理)、D组(奥敏清牙齿脱敏剂与氟化物联合处理),分别处理2 min×2次/d×7 d。用激光荧光龋探测仪(DIAGN-Odent)记录各时间点的荧光值,扫描电镜(SEM)观察各组釉质表面形态。结果:与A组相比,再矿化处理后B、C、D组荧光值显著降低(P<0.01)。D组荧光值显著低于B、C组(P<0.05),而B、C两组无统计学差异(P>0.05)。SEM下经奥敏清牙齿脱敏剂或氟化物处理后表面均有一定沉积物。结论:奥敏清牙齿脱敏剂具有促乳牙脱矿釉质再矿化的作用,与氟化物联合应用具有加强协同作用。%Objective:To study the effect of topical Minqing Ao dental desensitizer application on the remineraliza-tion of primary teeth enamel eroded by Cola. Method:30 retained human primary molars were collected at clinic.Each tooth was cut bucco-lingually and mesial-distally into four sections. These sections assigned randomly to one of four groups (n=30). The enamel slabs were first immersed into a carbonated acidic drink for demineralization treatment for seven days(10 min×10 times/d),then they were treated as follows for seven days(2 min×2 times/d):Group A(unexposed to any prod-uct)、Group B(Minqing Ao dental desensitizer)、Group C(fluoride)、Group D(Minqing Ao dental desensitizer +fluoride). A laser fluorescence system(DIAGNOdent)was used to make a quantitative record,The morphological changes of surface were observed by scanning electron microscope (SEM). Result:Compared with group A after

  10. Artificial sweeteners - a review.

    Science.gov (United States)

    Chattopadhyay, Sanchari; Raychaudhuri, Utpal; Chakraborty, Runu

    2014-04-01

    Now a days sugar free food are very much popular because of their less calorie content. So food industry uses various artificial sweeteners which are low in calorie content instead of high calorie sugar. U.S. Food and Drug Administration has approved aspartame, acesulfame-k, neotame, cyclamate and alitame for use as per acceptable daily intake (ADI) value. But till date, breakdown products of these sweeteners have controversial health and metabolic effects. On the other hand, rare sugars are monosaccharides and have no known health effects because it does not metabolize in our body, but shows same sweet taste and bulk property as sugar. Rare sugars have no such ADI value and are mainly produced by using bioreactor and so inspite of high demand, rare sugars cannot be produced in the desired quantities. PMID:24741154

  11. Artificial Immune Systems (2010)

    CERN Document Server

    Greensmith, Julie; Aickelin, Uwe

    2010-01-01

    The human immune system has numerous properties that make it ripe for exploitation in the computational domain, such as robustness and fault tolerance, and many different algorithms, collectively termed Artificial Immune Systems (AIS), have been inspired by it. Two generations of AIS are currently in use, with the first generation relying on simplified immune models and the second generation utilising interdisciplinary collaboration to develop a deeper understanding of the immune system and hence produce more complex models. Both generations of algorithms have been successfully applied to a variety of problems, including anomaly detection, pattern recognition, optimisation and robotics. In this chapter an overview of AIS is presented, its evolution is discussed, and it is shown that the diversification of the field is linked to the diversity of the immune system itself, leading to a number of algorithms as opposed to one archetypal system. Two case studies are also presented to help provide insight into the m...

  12. Artificial Enzymes, "Chemzymes"

    DEFF Research Database (Denmark)

    Bjerre, Jeannette; Rousseau, Cyril Andre Raphaël; Pedersen, Lavinia Georgeta M;

    2008-01-01

    "Chemzymes", based on cyclodextrins and other molecules. Only the chemzymes that have shown enzyme-like activity that has been quantified by different methods will be mentioned. This review will summarize the work done in the field of artificial glycosidases, oxidases, epoxidases, and esterases, as well...... as chemzymes that catalyze conjugate additions, cycloadditions, and self-replicating processes. The focus will be mainly on cyclodextrin-based chemzymes since they have shown to be good candidate structures to base an enzyme model skeleton on. In addition hereto, other molecules that encompass binding......Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models...

  13. Instructional Applications of Artificial Intelligence.

    Science.gov (United States)

    Halff, Henry M.

    1986-01-01

    Surveys artificial intelligence and the development of computer-based tutors and speculates on the future of artificial intelligence in education. Includes discussion of the definitions of knowledge, expert systems (computer systems that solve tough technical problems), intelligent tutoring systems (ITS), and specific ITSs such as GUIDON, MYCIN,…

  14. Sucrose compared with artificial sweeteners

    DEFF Research Database (Denmark)

    Sørensen, Lone Brinkmann; Vasilaras, Tatjana H; Astrup, Arne;

    2014-01-01

    There is a lack of appetite studies in free-living subjects supplying the habitual diet with either sucrose or artificially sweetened beverages and foods. Furthermore, the focus of artificial sweeteners has only been on the energy intake (EI) side of the energy-balance equation. The data are from...

  15. Artificial Ligaments: Promise or Panacea?

    Science.gov (United States)

    Lubell, Adele

    1987-01-01

    The Food and Drug Administration has approved a prosthetic ligament for limited use in persons with damaged anterior cruciate ligaments (ACL). This article addresses ligament repair, ACL tears, current treatment, development of the Gore-Tex artificial ligament, other artificial ligaments in process, and arguments for and against their use.…

  16. Artificial Boundary Method for Calculating Ship Wave Resistance

    Institute of Scientific and Technical Information of China (English)

    文新; 韩厚德

    2003-01-01

    The calculation of wave resistance for a ship moving at constant speed near a free surface is considered. This wave resistance is calculated with a linearized steady potential model. To deal with the unboundedness of the physical domain in the potential flow problem, we introduce one vertical side as an artificial upstream boundary and two vertical sides as the artificial downstream boundaries. On the artificial boundaries, a sequence of high-order global artificial boundary conditions are given. Then the potential flow problem is reduced to a problem defined on a finite computational domain, which is equivalent to a variational problem. The solution of the variational problem by the finite element method gives the numerical approximation of the potential flow around the ship, which was used to calculate the wave resistance. The numerical examples show the accuracy and efficiency of the proposed numerical scheme.

  17. Soft computing in artificial intelligence

    CERN Document Server

    Matson, Eric

    2014-01-01

    This book explores the concept of artificial intelligence based on knowledge-based algorithms. Given the current hardware and software technologies and artificial intelligence theories, we can think of how efficient to provide a solution, how best to implement a model and how successful to achieve it. This edition provides readers with the most recent progress and novel solutions in artificial intelligence. This book aims at presenting the research results and solutions of applications in relevance with artificial intelligence technologies. We propose to researchers and practitioners some methods to advance the intelligent systems and apply artificial intelligence to specific or general purpose. This book consists of 13 contributions that feature fuzzy (r, s)-minimal pre- and β-open sets, handling big coocurrence matrices, Xie-Beni-type fuzzy cluster validation, fuzzy c-regression models, combination of genetic algorithm and ant colony optimization, building expert system, fuzzy logic and neural network, ind...

  18. Beyond AI: Artificial Dreams Conference

    CERN Document Server

    Zackova, Eva; Kelemen, Jozef; Beyond Artificial Intelligence : The Disappearing Human-Machine Divide

    2015-01-01

    This book is an edited collection of chapters based on the papers presented at the conference “Beyond AI: Artificial Dreams” held in Pilsen in November 2012. The aim of the conference was to question deep-rooted ideas of artificial intelligence and cast critical reflection on methods standing at its foundations.  Artificial Dreams epitomize our controversial quest for non-biological intelligence, and therefore the contributors of this book tried to fully exploit such a controversy in their respective chapters, which resulted in an interdisciplinary dialogue between experts from engineering, natural sciences and humanities.   While pursuing the Artificial Dreams, it has become clear that it is still more and more difficult to draw a clear divide between human and machine. And therefore this book tries to portrait such an image of what lies beyond artificial intelligence: we can see the disappearing human-machine divide, a very important phenomenon of nowadays technological society, the phenomenon which i...

  19. Evaluation of the mineralization degree of the vestibular surface of the upper central incisors with a 655-nm diode laser in mouth breathers: preliminary results

    Science.gov (United States)

    Pinheiro Ladalardo, Thereza C. C. G.; Cappellette, Mario, Jr.; Zanin, Fatima A. A.; Brugnera, Aldo, Jr.; Anthero de Azevedo, Ramiro; Pignatari, Shirley; Weckx, Luc L. M.

    2003-06-01

    Mouth breathing unbalances the physiological mechanisms of the dental surface hydration by compromising lip closure, and, very often, causing the vestibular positioning of upper incisors. That variance leads to the interruption of the dental demineralization and remineralization feedback, prevailing a demineralized condition of the dental surface which increases caries risk. The laser fluorescence examination allows an early demineralization diagnosis, thus it makes possible through preventive measures to minimize the risk factor - dental mineral structure loss - in the bacterial infection of the demineralized area, and hence, preventing invasive therapeutical procedures. A DIAGNOdent apparatus was used to evaluate the mineralization degree of the upper central incisors in 40 patients - twenty of them with a mouth breathing diagnosis; the remaining twenty were nasal breathers (control group). Age ranging from 6 to 12 years, both male and female. To measure the vestibular surface of the incisors, it was divided into 3 segments: cervical, medial and incisal. The average of the results pertaining to the mouth breathing patients was as follows: tooth 11 cervical third - 5.45, medial third - 7.15, incisal third - 7.95, and tooth 21 - cervical third - 5.95, medial third - 7.25, incisal third - 8.15. The control patients, nasal breathers, presented the following results: tooth 11 cervical third - 1.75, medial third - 2.30, incisal third - 1.85, and tooth 21 - cervical third - 1.80, medial third - 2.20, incisal third - 2.15. The mouth breathing patients showed demineralization in the teeth examined at the initial stage, subclinical, comparing with the control patients, nasal breathers, who did not present any mineral deficit in these teeth.

  20. Application of fluoride in the prevention of orthodontic demineralization%氟化物在预防正畸脱矿中的应用

    Institute of Scientific and Technical Information of China (English)

    李黎

    2014-01-01

    目的:探讨氟化物在预防正畸脱矿中的应用效果。方法:2009年3月-2011年12月收治错畸形患者90例,所有患者在治疗前后记录牙齿脱矿的部位、牙位及程度。治疗方法均采用直丝弓矫治技术治疗,矫治时间13~27个月,平均18.9个月,在矫正过程中让患者每天用含氟牙膏刷牙。结果:本组90例患者经过治疗后,发生牙齿脱矿370颗,其中上颌牙齿发生脱矿212颗(9.8%),其中上颌侧切牙58颗,上颌中切牙42颗,上颌尖牙40颗,上颌第一前磨牙22颗,上颌第二前磨牙24颗,上颌第一磨牙26颗;下颌牙齿发生脱矿158颗(7.3%),其中下颌侧切牙36颗,下颌中切牙20颗,下颌尖牙34颗,下颌第一前磨牙26颗,下颌第二前磨牙16颗,下颌第一磨牙26颗。治疗前发生牙齿脱矿16例(17.8%),牙齿脱矿颗数130颗(6.0%),经过矫正后,牙齿脱矿44例(48.9%),牙齿脱矿颗数共370颗(17.1%),其中1级282颗,2级88颗。结论:在口腔正畸治疗过程中牙釉质脱矿应该引起重视,要采取必要的措施进行预防。%Objective:To explore the application effect of fluoride in the prevention of orthodontic.Methods:50 cases with malocclusion were selected from March 2009 to December 2011.The tooth demineralization parts,tooth position and degree of all the patients were recorded before and after treatment.The therapeutic method was straight arch wire technique treatment.The treatment time was 13~27 months,and the average was 18.9 months.The patients used fluoride toothpaste every day in the correction process.Results:90 cases of this group after treatment,370 teeth occurred demineralization.212 teeth(9.8% ) were maxillary teeth,among 58 teeth were maxillary lateral incisors,42 teeth were maxillary central incisor,40 teeth were maxillary canine,22 teeth were maxillary first premolars,24 teeth were maxillary second premolars,26 teeth were maxillary first molar.158 teeth(7

  1. Artificial surfaces in the Raya Central Iberica Use generalized linear models to define driving forces of the territorial changes; Las superficies artificiales en la Raya Central Iberica El uso de modelos lineales generalizados para definir los factores condicionantes de los cambios territoriales

    Energy Technology Data Exchange (ETDEWEB)

    Jaraiz Cabanillas, F. J.; Mora Aliseda, J.; Gutierrez Gallego, J. A.

    2012-07-01

    The rapid changes that the socio-demographic structure and the economic activity are experiencing in the Raya Central Iberica, and that are produced for the new socioeconomic needs, the concentration of the population in the principal cities, the abandon of the rural spaces, the growth of irrigation areas, etc., they motivate changes in the artificial surfaces. A spatial analysis is applied to determine the principal driving forces of the artificial surfaces changes. For this, different tools are in use in order to differentiate the land use and land cover changes or the driving forces. The changes were quantified by statistical technologies and images of CORINE Land Cover Project and the driving factors were analyzed by logistic regressions (generalized linear models) combining human and geophysics variables. Conclusions show the suitability of the employment of the information of CORINE Land Cover project, the significant selected independent variables, and the validity of the generalized linear models for the explanation of the land use and land cover change of a certain territory. (Author)

  2. 人工关节假体材料表面物理特性对结核分枝杆菌黏附的影响研究%Impact of surface physical properties of artificial joint prosthesis materials on adhesion of Mycobacterium tuberculosis

    Institute of Scientific and Technical Information of China (English)

    张瑞斐; 黄迅悟; 孙继桐; 李洪敏; 包二平; 朱森

    2014-01-01

    Objective To study the effect of surface physical properties of different materials for the artificial joint pros -thesis interface on Mycobacterium tuberculosis adhesion .Methods The surface polishing coating , titanium coating and hydroxyapatite coating were chosen as the experimental materials to analyze the surface topography and measure the surface roughness, contact angle and surface energy .The M.tuberculosis strains were used by in vitro cultivation method and ob-served by scanning electron microscopy (SEM) to study the morphology of M.tuberculosis and the material surface adhe-sion.The influence of surface physical properties of the interface of the artificial joint prostheses on the proliferation and ad -hesion of bacteria was evaluatd .Results The titanium coating and hydroxyapatite coating materials were hydrophobic , while the surface polishing coating was hydrophilic .The contact angle and surface energy were significantly different ( P0.05)in the OD value of bacterial solution .The titanium coating had the largest amount of interface adhesion for M.tuberculosis, fol-lowed by the hydroxyapatite coating and the polishing coating .The difference between various materials was statistically sig-nificant (P<0.05).Conclusion The adhesion of M.tuberculosis in the surface of artificial joint prosthesis materials is closely related to the surface physical properties .A adhesiveness improves with surface roughness .%目的:探讨不同人工关节假体材料表面物理特性对结核分枝杆菌( MTB )黏附的影响。方法以表面抛光涂层、钛涂层和羟基磷灰石涂层为实验材料,对材料进行表面形貌分析以及表面粗糙度、接触角和表面能的测定。选用MTB为研究菌株,体外共培养法培养,通过扫描电镜对MTB的形态、在材料表面的黏附情况和黏附量进行观察。综合评价人工关节假体材料的表面物理特性对细菌增殖和黏附的影响。结果钛涂层和羟基磷灰

  3. Effect of a glass ionomer cement and a fluoride varnish on cross-sectional microhardness values of artificial occlusal caries: In vitro study

    Directory of Open Access Journals (Sweden)

    MWM Souchois

    2012-01-01

    Conclusions: This in vitro study demonstrated that the use of GIC over an artificial active WSLs and exposed to an artificially HRCC setting tend to express some effect in increased surface KHN values.

  4. 牙周致病菌的共聚及其对人工牙根面黏附力的影响%Coaggregation of periodontal pathogens and its effect on the attachment on artificial root surface

    Institute of Scientific and Technical Information of China (English)

    王耀生; 杜奇峰; 李永凯; 徐屹

    2012-01-01

    Objective The coaggregation abilities of 4 strains of periodontal pathogens Fusobacterium nuclea-tum(F.nucleatum), Porphytomonas gingivalis(P.gingivalis), Prevotella intermedia(P.intermedia) and Haemophilus actinomycetemcomitans(H.actlnomycetemcomitans) were compared The changes of the ability of periodontal pathogens attaching to artificial root surface mediated by F.nucleatum were observed in order to investigate the possible interaction of the bacteria in periodontal biofilm. Methods The coaggregation degree among 4 strains of periodontal pathogens was investigated by a visual assay. Differences of the adherent percent of periodontal pathogens to collagen-coated hydroxyapatite(c-HA) under two conditions when F.nucleatum had already bond to c-(H)A and when F.nucleatum had not, were detected by radioisotope scintillation counter. Results The coaggregation among 4 studied strains was observed. The coaggregation degrees between F.nucleatum and P.gingivalis, as well as between P.gingivalis and P.intermedia reached 4. The coaggregation degrees of F.nucleatum with the other three bacteria were higher than 3. The adherent percent of P.gingivalis, P.intermedia and H.actinomycetemcomitans to c-HA when F.nucleatum had already bond to c-HA were higher than that when F.nucleatum had not. The adherent percent of F.nucleatum to c-HA when F.nucleatum had already bond to c-HA were lower than that when F.nucleatum had not. Conclusion The periodontal pathogens coaggregate. F.nucleatum may play a role as a bridge in the colonization of the other periodontal pathogens in the periodontal biofilm.%目的 比较具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌等牙周病致病菌彼此之间的共聚力大小,观察四者在具核梭杆菌介导下对人工牙根面黏附力的影响,了解牙周生物膜结构中细菌间可能存在的相互作用.方法 目测具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌彼此间

  5. Artificial Sweeteners in a Large Canadian River Reflect Human Consumption in the Watershed

    OpenAIRE

    John Spoelstra; Sherry L Schiff; Brown, Susan J.

    2013-01-01

    Artificial sweeteners have been widely incorporated in human food products for aid in weight loss regimes, dental health protection and dietary control of diabetes. Some of these widely used compounds can pass non-degraded through wastewater treatment systems and are subsequently discharged to groundwater and surface waters. Measurements of artificial sweeteners in rivers used for drinking water production are scarce. In order to determine the riverine concentrations of artificial sweeteners ...

  6. natural or artificial diets

    Directory of Open Access Journals (Sweden)

    A. O. Meyer-Willerer

    2005-01-01

    Full Text Available Se probaron alimentos artificiales y naturales con larva de camarón (Litopenaeus vannamei cultivados en diferentes recipientes. Estos fueron ocho frascos cónicos con 15L, ocho acuarios con 50L y como grupo control, seis tanques de fibra de vidrio con 1500L; todos con agua marina fresca y filtrada. La densidad inicial en todos los recipientes fue de 70 nauplios/L. Aquellos en frascos y acuarios recibieron ya sea dieta natural o artificial. El grupo control fue cultivado con dieta natural en los tanques grandes que utilizan los laboratorios para la producción masiva de postlarvas. El principal producto de excreción de larva de camarón es el ión amonio, que es tóxico cuando está presente en concentraciones elevadas. Se determinó diariamente con el método colorimétrico del indofenol. Los resultados muestran diferencias en la concentración del ión amonio y en la sobrevivencia de larvas entre las diferentes dietas y también entre los diferentes recipientes. En aquellos con volúmenes pequeños comparados con los grandes, se presentó mayor concentración de amonio (500 a 750µg/L, en aquellos con dietas naturales, debido a que este ión sirve de fertilizante a las algas adicionadas, necesitando efectuar recambios diarios de agua posteriores al noveno día de cultivo para mantener este ión a una concentración subletal. Se obtuvo una baja cosecha de postlarvas (menor a 15% con el alimento artificial larvario, debido a la presencia de protozoarios, alimentándose con el producto comercial precipitado en el fondo de los frascos o acuarios. Los acuarios con larvas alimentadas con dieta natural también mostraron concentraciones subletales de amonio al noveno día; sin embargo, la sobrevivencia fue cuatro veces mayor que con dietas artificiales. Los tanques control con dietas naturales presentaron tasas de sobrevivencia (70 ± 5% similares a la reportada por otros laboratorios.

  7. [Research and development of artificial retina material].

    Science.gov (United States)

    Hu, Ning; Yang, Jun; Peng, Chenglin; Wang, Xing; Zhang, Sijie; Zhang, Ying; Zheng, Erxin

    2008-04-01

    The application of artificial retina was introduced. The principal characteristics of artificial retina material were reviewed in particular. Moreover, the recent research development and application prospect were discussed.

  8. The effects of diammine silver fluoride solution on demineralized dentine adhesion ability%氟化氨银溶液对人工脱矿牙本质粘接强度的影响

    Institute of Scientific and Technical Information of China (English)

    汪淑华; 阎帆; 肖芳; 张珂; 连文海

    2016-01-01

    Objective:To investigate the effect of silver diamine fluoride(SDF)on the bonding strength between dentine and glass ion-omer cement(GIC).Methods:1 2 extracted sound molars were prepared into dintine samples and distributed into sound dentine group and demineralized dentine group.According to the treatment methods,the samples in each group were respectively divided into 3 sub-groups:A(control group),B[coated with 38% Ag(NH3 )F2 ]and C(SDF treatment with additional lighting-curing)(n =20).Then a hand-mixed conventional glass ionomer cement Fuji IX was placed on the dentine surface.After 24 h,micro tensile bond strength test and scanning electron microscope (SEM)analysis were conducted.Results:The bonding strength of demineralized dentine was higher than that of sound dentine(P <0.01 ).SDF with additional lighting-curing treated dentine showed a higer bonding strength value than only SDF treated dentin(P <0.01 ).Conclusion:SDF may improve the bonding between dentine and GIC.%目的:评价氟化氨银溶液(silver diammine fluoride,SDF)对人工龋牙本质和玻璃离子粘固剂(glass ionomer cement,GIC)之间的微拉伸粘接强度的影响。方法:将12颗人离体磨牙制备成脱矿牙本质和未脱矿牙本质2组标本,均分为对照组、氟化氨银组及氟化氨银与光固化联合处理组(n =20),将处理完成的牙本质与 GIC 富士 IX 粘接,24 h 后对标本进行切割及微拉伸强度试验,最后用扫描电镜观察牙本质与 GIC 之间的超微结构,并进行数据统计分析。结果:脱矿后牙本质的粘接强度显著高于未脱矿的牙本质(P <0.01)。经过光固化 SDF 处理的人工龋牙本质的粘接强度数值显著高于只经 SDF 处理的人工龋牙本质的粘接强度(P <0.01)。结论:SDF 处理的人工脱矿牙本质与 GIC 之间的微拉伸粘接强度得到显著提高。

  9. Bioengineering of Artificial Lymphoid Organs.

    Science.gov (United States)

    Nosenko, M A; Drutskaya, M S; Moisenovich, M M; Nedospasov, S A

    2016-01-01

    This review addresses the issue of bioengineering of artificial lymphoid organs.Progress in this field may help to better understand the nature of the structure-function relations that exist in immune organs. Artifical lymphoid organs may also be advantageous in the therapy or correction of immunodefficiencies, autoimmune diseases, and cancer. The structural organization, development, and function of lymphoid tissue are analyzed with a focus on the role of intercellular contacts and on the cytokine signaling pathways regulating these processes. We describe various polymeric materials, as scaffolds, for artificial tissue engineering. Finally, published studies in which artificial lymphoid organs were generated are reviewed and possible future directions in the field are discussed.

  10. Artificial Immune Systems Tutorial

    CERN Document Server

    Aickelin, Uwe

    2008-01-01

    The biological immune system is a robust, complex, adaptive system that defends the body from foreign pathogens. It is able to categorize all cells (or molecules) within the body as self-cells or non-self cells. It does this with the help of a distributed task force that has the intelligence to take action from a local and also a global perspective using its network of chemical messengers for communication. There are two major branches of the immune system. The innate immune system is an unchanging mechanism that detects and destroys certain invading organisms, whilst the adaptive immune system responds to previously unknown foreign cells and builds a response to them that can remain in the body over a long period of time. This remarkable information processing biological system has caught the attention of computer science in recent years. A novel computational intelligence technique, inspired by immunology, has emerged, called Artificial Immune Systems. Several concepts from the immune have been extracted an...

  11. Artificial Immune Systems

    CERN Document Server

    Aickelin, Uwe

    2009-01-01

    The biological immune system is a robust, complex, adaptive system that defends the body from foreign pathogens. It is able to categorize all cells (or molecules) within the body as self-cells or non-self cells. It does this with the help of a distributed task force that has the intelligence to take action from a local and also a global perspective using its network of chemical messengers for communication. There are two major branches of the immune system. The innate immune system is an unchanging mechanism that detects and destroys certain invading organisms, whilst the adaptive immune system responds to previously unknown foreign cells and builds a response to them that can remain in the body over a long period of time. This remarkable information processing biological system has caught the attention of computer science in recent years. A novel computational intelligence technique, inspired by immunology, has emerged, called Artificial Immune Systems. Several concepts from the immune have been extracted an...

  12. Placement of implants in an ossifying fibroma defect obliterated with demineralized, freeze-dried bone allograft and Plasma-rich growth factor

    Directory of Open Access Journals (Sweden)

    Umashankar Pal

    2012-01-01

    Full Text Available There has been considerable clinical interest in combining the grafts, particularly bone allografts for support for dental implants, soft-tissue support, periodontal maintenance, and ovate pontic formation. The use of demineralized, freeze-dried bone allograft (DFDBA offers certain advantages over other graft materials and can avoid the need for a second-site surgery for autogenous donor bone. The advantages of DFDBA include handling properties, osteoinductivity, membrane tenting, and less susceptibility to migration after placement. This article will review available grafting materials and demonstrate a case of ossifying fibroma of the mandible, which was treated by curettage and hollow cavity filled with DFDBA. Six months follow-up period showed successful graft result and this grafted bone form was utilized for implant supported prosthesis.

  13. Change of microbiological composition of deminer-alized dentin from the bottom of carious cavity during the course of treatment of acute deep caries in children

    Directory of Open Access Journals (Sweden)

    Kazakova L.N.

    2013-09-01

    Full Text Available Purpose: to compare the antimicrobial efficacy of chlorhexidine bigluconate used in different forms for the treatment of acute deep caries, to define the percentage of complications in the treatment of acute deep caries in children on the stage of its development in 6 and 12 months. Material and methods: Bacteriological study of demineralized dentin taken from the bottom of «the work space» by the sterile instrument, clinical monitoring of children after 6 and 12 months. Results. A significant reduction of colonies forming odontopathogenic and opportunistic microorganisms during the application of the film «Diplen» and a high percentage of favorable outcomes over the period of follow-up in the second study group. Conclusion. Qualitative etiological treatment conducted in a timely manner taking into account the structural features of hard and soft tissues of the tooth, creates the conditions for full formation of all tooth tissues.

  14. Artificial Intelligence in Civil Engineering

    Directory of Open Access Journals (Sweden)

    Pengzhen Lu

    2012-01-01

    Full Text Available Artificial intelligence is a branch of computer science, involved in the research, design, and application of intelligent computer. Traditional methods for modeling and optimizing complex structure systems require huge amounts of computing resources, and artificial-intelligence-based solutions can often provide valuable alternatives for efficiently solving problems in the civil engineering. This paper summarizes recently developed methods and theories in the developing direction for applications of artificial intelligence in civil engineering, including evolutionary computation, neural networks, fuzzy systems, expert system, reasoning, classification, and learning, as well as others like chaos theory, cuckoo search, firefly algorithm, knowledge-based engineering, and simulated annealing. The main research trends are also pointed out in the end. The paper provides an overview of the advances of artificial intelligence applied in civil engineering.

  15. Artificial Life Meets Computational Creativity?

    OpenAIRE

    McMullin, Barry

    2009-01-01

    I (briefly) review the history of work in Artificial Life on the problem of the open-ended evolutionary growth of complexity in computational worlds. This is then put into the context of evolutionary epistemology and human creativity.

  16. Darwin, artificial selection, and poverty.

    Science.gov (United States)

    Sanchez, Luis

    2010-03-01

    This paper argues that the processes of evolutionary selection are becoming increasingly artificial, a trend that goes against the belief in a purely natural selection process claimed by Darwin's natural selection theory. Artificial selection is mentioned by Darwin, but it was ignored by Social Darwinists, and it is all but absent in neo-Darwinian thinking. This omission results in an underestimation of probable impacts of artificial selection upon assumed evolutionary processes, and has implications for the ideological uses of Darwin's language, particularly in relation to poverty and other social inequalities. The influence of artificial selection on genotypic and phenotypic adaptations arguably represents a substantial shift in the presumed path of evolution, a shift laden with both biological and political implications.

  17. Artificial Reefs and Ocean Dumping.

    Science.gov (United States)

    Glueck, Richard D.

    1983-01-01

    Activities and instructional strategies for two multigrade lessons are provided. Activity objectives include describing an artificial reef (such as a sunken ocean liner) as an ecosystem, knowing animal types in the ecosystem, and describing a food web. (JN)

  18. Parallel artificial liquid membrane extraction

    DEFF Research Database (Denmark)

    Gjelstad, Astrid; Rasmussen, Knut Einar; Parmer, Marthe Petrine;

    2013-01-01

    This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated by an arti......This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated...... by an artificial liquid membrane. Parallel artificial liquid membrane extraction is a modification of hollow-fiber liquid-phase microextraction, where the hollow fibers are replaced by flat membranes in a 96-well plate format....

  19. Food analysis using artificial senses.

    Science.gov (United States)

    Śliwińska, Magdalena; Wiśniewska, Paulina; Dymerski, Tomasz; Namieśnik, Jacek; Wardencki, Waldemar

    2014-02-19

    Nowadays, consumers are paying great attention to the characteristics of food such as smell, taste, and appearance. This motivates scientists to imitate human senses using devices known as electronic senses. These include electronic noses, electronic tongues, and computer vision. Thanks to the utilization of various sensors and methods of signal analysis, artificial senses are widely applied in food analysis for process monitoring and determining the quality and authenticity of foods. This paper summarizes achievements in the field of artificial senses. It includes a brief history of these systems, descriptions of most commonly used sensors (conductometric, potentiometric, amperometic/voltammetric, impedimetric, colorimetric, piezoelectric), data analysis methods (for example, artificial neural network (ANN), principal component analysis (PCA), model CIE L*a*b*), and application of artificial senses to food analysis, in particular quality control, authenticity and falsification assessment, and monitoring of production processes.

  20. Artificial weathering of granite

    Directory of Open Access Journals (Sweden)

    Silva Hermo, B.

    2008-06-01

    Full Text Available This article summarizes a series of artificial weathering tests run on granite designed to: simulate the action of weathering agents on buildings and identify the underlying mechanisms, determine the salt resistance of different types of rock; evaluate consolidation and water-repellent treatment durability; and confirm hypotheses about the origin of salts such as gypsum that are often found in granite buildings. Salt crystallization tests were also conducted, using sodium chloride, sodium sulphate, calcium sulphate and seawater solutions. One of these tests was conducted in a chamber specifically designed to simulate salt spray weathering and another in an SO2 chamber to ascertain whether granite is subject to sulphation. The test results are analyzed and discussed, along with the shortcomings of each type of trial as a method for simulating the decay observed in monuments. The effect of factors such as wet-dry conditions, type of saline solution and the position of the planes of weakness on the type of decay is also addressed.En este trabajo se hace una síntesis de varios ensayos de alteración artificial realizados con rocas graníticas. Estos ensayos tenían distintos objetivos: reproducir las formas de alteración encontradas en los edificios para llegar a conocer los mecanismos que las generan, determinar la resistencia de las diferentes rocas a la acción de las sales, evaluar la durabilidad de tratamientos de consolidación e hidrofugación y constatar hipótesis acerca del origen de algunas sales, como el yeso, que aparecen frecuentemente en edificios graníticos. En los ensayos de cristalización de sales se utilizaron disoluciones de cloruro de sodio, sulfato de sodio, sulfato de calcio y agua de mar. Uno de estos ensayos se llevó a cabo en una cámara especialmente diseñada para reproducir la alteración por aerosol marino y otro se realizó en una cámara de SO2, con el objeto de comprobar si en rocas graníticas se puede producir

  1. Medical applications of artificial intelligence

    CERN Document Server

    Agah, Arvin

    2013-01-01

    Enhanced, more reliable, and better understood than in the past, artificial intelligence (AI) systems can make providing healthcare more accurate, affordable, accessible, consistent, and efficient. However, AI technologies have not been as well integrated into medicine as predicted. In order to succeed, medical and computational scientists must develop hybrid systems that can effectively and efficiently integrate the experience of medical care professionals with capabilities of AI systems. After providing a general overview of artificial intelligence concepts, tools, and techniques, Medical Ap

  2. Mechanical properties of artificial snow

    OpenAIRE

    Lintzén, Nina

    2013-01-01

    Mechanical properties of snow have been a subject of research since the mid-20th century. Theresearch done is based on natural snow. During the last decades the winter business industryhas been growing and also the interest for constructing buildings and artwork of snow. Suchconstructions are generally built using artificial snow, i.e. snow produced by snow guns. Up tothe present constructions of snow are designed based on knowledge by experience. Only minorscientific studies on artificial sn...

  3. What are artificial neural networks?

    DEFF Research Database (Denmark)

    Krogh, Anders

    2008-01-01

    Artificial neural networks have been applied to problems ranging from speech recognition to prediction of protein secondary structure, classification of cancers and gene prediction. How do they work and what might they be good for? Udgivelsesdato: 2008-Feb......Artificial neural networks have been applied to problems ranging from speech recognition to prediction of protein secondary structure, classification of cancers and gene prediction. How do they work and what might they be good for? Udgivelsesdato: 2008-Feb...

  4. The handbook of artificial intelligence

    CERN Document Server

    Barr, Avron

    1982-01-01

    The Handbook of Artificial Intelligence, Volume II focuses on the improvements in artificial intelligence (AI) and its increasing applications, including programming languages, intelligent CAI systems, and the employment of AI in medicine, science, and education. The book first elaborates on programming languages for AI research and applications-oriented AI research. Discussions cover scientific applications, teiresias, applications in chemistry, dependencies and assumptions, AI programming-language features, and LISP. The manuscript then examines applications-oriented AI research in medicine

  5. Analysis of shock wave propagation from explosives using computational simulations and artificial schlieren imaging

    Science.gov (United States)

    Armstrong, Christopher; Hargather, Michael

    2014-11-01

    Computational simulations of explosions are performed using the hydrocode CTH and analyzed using artificial schlieren imaging. The simulations include one and three-dimensional free-air blasts and a confined geometry. Artificial schlieren images are produced from the density fields calculated via the simulations. The artificial schlieren images are used to simulate traditional and focusing schlieren images of explosions. The artificial schlieren images are compared to actual high-speed schlieren images of similar explosions. Computational streak images are produced to identify time-dependent features in the blast field. The streak images are used to study the interaction between secondary shock waves and the explosive product gas contact surface.

  6. Impacts of Artificial Reefs on Surrounding Ecosystems

    Science.gov (United States)

    Manoukian, Sarine

    addition, relative fish biomass estimates can be extrapolated. Results suggest that most of the fish aggregations are generally associated with the artificial modules showing a tendency for mid- and bottom-water depth distribution than for the surface waters. This study contributes to understanding the changes in artificial reefs over time in relation to coastal processes. Moreover, the preliminary results concerning the water column backscatter data represents progress in fisheries acoustics research as a result of three-dimensional acoustics. They demonstrate the benefits of multibeam sonar as a tool to investigate and quantify size distribution and geometry of fish aggregations associated with shallow marine habitats.

  7. Artificial saliva effect on toxic substances release from acrylic resins

    Directory of Open Access Journals (Sweden)

    Kostić Milena

    2015-01-01

    Full Text Available Background/Aim. Acrylic-based resins are intensively used in dentistry practice as restorative or denture-base materials. The purpose of this study was to analyze the surface structure of denture base resins and the amount of released potentially toxic substances (PTS immediately upon polymerization and incubation in different types of artificial saliva. Methods. Storage of acrylic samples in two models of artificial saliva were performed in a water bath at the temperature of 37 ± 1°C. Analysis of the surface structure of samples was carried out using scanning electronic microscopy analysis immediately after polymerization and after the 30-day incubation. The amounts of PTS per day, week and month extracts were measured using high-pressure liquid chromatography. Results. Surface design and amount of PTS in acrylic materials were different and depended on the types and duration of polymerization. The surfaces of tested acrylates became flatter after immersing in solutions of artificial saliva. The degree of acrylic materials release was not dependent on the applied model of artificial saliva. Conclusion. In order to improve biological features of acrylic resin materials, it was recommended that dentures lined with soft or hard coldpolymerized acrylates should be kept at least 1 to 7 days in water before being given to a patient. So, as to reach high degree of biocompatibility preparation of prosthetic restorations from heat-polymerized acrylate was unnecessary. [Projekat Ministarstva nauke Republike Srbije, br. 41017

  8. Development of a totally implantable artificial larynx

    NARCIS (Netherlands)

    Verkerke, GJ; Veenstra, Aalze; de Vries, MP; Schutte, HK; Busscher, HJ; Herrmann, IF; Van der Mei, HC; Rakhorst, G; Clements, MP

    1996-01-01

    Background. The consequences of a life-saving laryngectomy are still very distressing. The Eureka project "Artificial Larynx" aims at realization of an implantable artificial larynx to eliminate all drawbacks. Methods. The artificial larynx will consist of artificial vocal folds of adjustable pitch

  9. Artificial gravity in space and in medical research

    Science.gov (United States)

    Cardus, D.

    1994-01-01

    The history of manned space flight has repeatedly documented the fact that prolonged sojourn in space causes physiological deconditioning. Physiological deterioration has raised a legitimate concern about man's ability to adequately perform in the course of long missions and even the possibility of leading to circumstances threatening survival. One of the possible countermeasures of physiological deconditioning, theoretically more complete than others presently used since it affects all bodily systems, is artificial gravity. Space stations and spacecrafts can be equipped with artificial gravity, but is artificial gravity necessary? The term "necessary" must be qualified because a meaningful answer to the question depends entirely on further defining the purpose of space travel. If man intends to stay only temporarily in space, then he must keep himself in good physical condition so as to be able to return to earth or to land on any other planetary surface without undue exposure to major physiological problems resulting from transition through variable gravitational fields. Such a situation makes artificial gravity highly desirable, although perhaps not absolutely necessary in the case of relative short exposure to microgravity, but certainly necessary in interplanetary flight and planetary landings. If the intent is to remain indefinitely in space, to colonize space, then artificial gravity may not be necessary, but in this case the consequences of long term effects of adaptation to weightlessness will have to be weighed against the biological evolutionary outcomes that are to be expected. At the moment, plans for establishing permanent colonies in space seem still remote. More likely, the initial phase of exploration of the uncharted solar system will take place through successive, scope limited, research ventures ending with return to earth. This will require man to be ready to operate in gravitational fields of variable intensity. Equipping spacecrafts or space

  10. Artificial_Micrometeorites

    CERN Document Server

    Dolya, S N

    2014-01-01

    An iron ball, a beryllium sphere and a tungsten tube segment with diameter twenty microns, are electrically charged while proton beam irradiating. These bodies are accelerated by the running pulse field in a spiral waveguide up to velocity: thirty kilometers per second. The accelerator, generating micrometeorites is placed at satellites on the Earth orbit. This article considers processes of penetration of micrometeorites into the Earth atmosphere. It is shown that micrometeorites evaporate at the height of one hundred kilometers-one hundred fifty kilometers from the surface of the Earth. A micrometeorite which is a segment of the beryllium tube equipped with a graphite cone in the head part is the very meteorite to reach the Earth surface without being broken.

  11. Biological Effects Of Artificial Illumination

    Science.gov (United States)

    Corth, Richard

    1980-10-01

    We are increasingly being warned of the possible effects of so called "polluted" light, that is light that differs in spectral content from that of sunlight. We should be concerned, we are told, because all animals and plants have evolved under this natural daylight and therefore any difference between that illuminant and the artificial illuminants that are on the market today, is suspect. The usual presentation of the differences between the sunlight and the artificial illuminants are as shown in Figure 1. Here we are shown the spectral power distribution of sunlight and Cool White fluorescent light. The spectral power distributions of each have been normalized to some convenient wavelength so that each can be seen and easily compared on the same figure. But this presentation is misleading for one does not experience artificial illuminants at the same intensity as one experiences sunlight. Sunlight intensities are ordinarily found to be in the 8000 to 10,000 footcandle range whereas artificial illuminants are rarely experienced at intensity levels greater than 100 footcandles. Therefore a representative difference between the two types of illumination conditions is more accurately represented as in Figure 2. Thus if evolutionary adaptations require that humans and other animals be exposed to sunlight to ensure wellbeing, it is clear that one must be exposed to sunlight intensities. It is not feasible to expect that artificially illuminated environments will be lit to the same intensity as sunlight

  12. Topical application of fluoride on enamel demineralization after orthodontic treatment effects%氟化物的应用对正畸治疗中牙釉质脱矿的影响作用研究

    Institute of Scientific and Technical Information of China (English)

    刘景; 袁媛; 古力巴哈·买买提力

    2015-01-01

    目的:探讨氟化物(氟保护漆、含氟牙膏)的应用对正畸治疗后牙釉质脱矿的影响及预防正畸后牙釉质脱矿的作用。方法选择在新疆医科大学第五附属医院口腔科接受固定正畸矫治患者60例,均采用直丝弓矫治技术,随机分为3组:对照组20例390颗牙,试验1组20例384颗牙,试验2组20例388颗牙。对照组采取日常口腔护理,不做任何治疗。试验1组采用含氟牙膏刷牙,于每日早、晚各1次,刷牙时间>3 min。试验2组涂布氟保护漆,每半年涂布1次,直至拆除矫治器。所有观察对象在治疗前及正畸治疗后(约2 a)拆除正畸部位托槽,计算牙釉质脱矿指数,使用激光龋齿探测仪探测荧光值和对脱矿程度进行评价。结果对照组390颗牙齿中,正畸治疗后有61颗牙齿脱矿,脱矿率为15.6%;试验1组384颗牙齿中,正畸治疗后有51颗牙齿脱矿,脱矿率为13.3%;试验2组388颗牙齿中,正畸治疗后有37颗牙齿脱矿,脱矿率为9.5%,3组脱矿率差异有统计学意义(χ2=6.452,P =0.040)。试验1组及试验2组治疗后脱矿指数及 DD 值低于对照组,试验2组低于试验1组,差异有统计学意义(P <0.05)。对照组脱矿以2度为主(54.1%),试验1组以1~2度为主(86.3%),试验2组以1度为主(78.4%)。结论氟保护漆和含氟牙膏均能起到预防正畸中牙釉质脱矿的作用,以氟保护漆作用更为明显,使用更为方便,患者依从性强,值得临床推广。%Objective To investigate the effect of topical application of fluoride on enamel demineralization after orthodontic treatment,compared the role of fluoride toothpaste,fluoride varnish on enamel deminer-alization after orthodontic prevention.Methods In our department,60 patients with fixed orthodontic ap-pliances were randomly divided into control group and two experimental groups,a total

  13. Effect of artificial saliva contamination on adhesion of dental restorative materials.

    Science.gov (United States)

    Shimazu, Kisaki; Karibe, Hiroyuki; Ogata, Kiyokazu

    2014-01-01

    The purpose of this study was to evaluate the effects of artificial saliva contamination on three restorative materials, namely, a glass ionomer cement (GIC), a resin-modified GIC (RMGIC), and a composite resin (CR), for which two different etching adhesive systems were used. Thus, three surface conditions were created on bovine teeth using artificial saliva: control, mild saliva contamination, and severe saliva contamination. The dentin bond strength for CR was significantly lower after artificial saliva contamination. There were, however, no significant differences among the three surface conditions in terms of the dentin and enamel bond strengths of GIC and RMGIC. Moreover, CR exhibited significantly greater microleakage after artificial saliva contamination, whereas no significant differences were found in GIC and RMGIC. The results showed that artificial saliva contamination did not affect the shear bond strengths of GIC and RMGIC or their degrees of microleakage.

  14. A review of football injuries on third and fourth generation artificial turfs compared with natural turf.

    Science.gov (United States)

    Williams, Sean; Hume, Patria A; Kara, Stephen

    2011-11-01

    Football codes (rugby union, soccer, American football) train and play matches on natural and artificial turfs. A review of injuries on different turfs was needed to inform practitioners and sporting bodies on turf-related injury mechanisms and risk factors. Therefore, the aim of this review was to compare the incidence, nature and mechanisms of injuries sustained on newer generation artificial turfs and natural turfs. Electronic databases were searched using the keywords 'artificial turf', 'natural turf', 'grass' and 'inj*'. Delimitation of 120 articles sourced to those addressing injuries in football codes and those using third and fourth generation artificial turfs or natural turfs resulted in 11 experimental papers. These 11 papers provided 20 cohorts that could be assessed using magnitude-based inferences for injury incidence rate ratio calculations pertaining to differences between surfaces. Analysis showed that 16 of the 20 cohorts showed trivial effects for overall incidence rate ratios between surfaces. There was increased risk of ankle injury playing on artificial turf in eight cohorts, with incidence rate ratios from 0.7 to 5.2. Evidence concerning risk of knee injuries on the two surfaces was inconsistent, with incidence rate ratios from 0.4 to 2.8. Two cohorts showed beneficial inferences over the 90% likelihood value for effects of artificial surface on muscle injuries for soccer players; however, there were also two harmful, four unclear and five trivial inferences across the three football codes. Inferences relating to injury severity were inconsistent, with the exception that artificial turf was very likely to have harmful effects for minor injuries in rugby union training and severe injuries in young female soccer players. No clear differences between surfaces were evident in relation to training versus match injuries. Potential mechanisms for differing injury patterns on artificial turf compared with natural turf include increased peak torque and

  15. Artificial ozone holes

    CERN Document Server

    Dolya, S N

    2014-01-01

    This article considers an opportunity of disinfecting a part of the Earth surface, occupying a large area of ten thousand square kilometers. The sunlight will cause dissociation of molecular bromine into atoms; each bromine atom kills thirty thousand molecules of ozone. Each bromine plate has a mass of forty milligrams grams and destroys ozone in the area of hundred square meters. Thus, to form the ozone hole over the area of ten thousand square kilometers, it is required to have the total mass of bromine equal to the following four tons.

  16. Natural water purification and water management by artificial groundwater recharge

    Institute of Scientific and Technical Information of China (English)

    Klaus-Dieter BALKE; Yan ZHU

    2008-01-01

    Worldwide, several regions suffer from water scarcity and contamination. The infiltration and subsurface storage of rain and fiver water can reduce water stress. Artificial groundwater recharge, possibly combined with bank filtration, plant puri- fication and/or the use of subsurface dams and artificial aquifers, is especially advantageous in areas where layers of gravel and sand exist below the earth's surface. Artificial infiltration of surface water into the uppermost aquifer has qualitative and quanti-tative advantages. The contamination of infiltrated fiver water will be reduced by natural attenuation. Clay minerals, iron hy-droxide and humic matter as well as microorganisms located in the subsurface have high decontamination capacities. By this, a final water treatment, if necessary, becomes much easier and cheaper. The quantitative effect concerns the seasonally changing fiver discharge that influences the possibility of water extraction for drinking water purposes. Such changes can be equalised by seasonally adapted infiltration/extraction of water in/out of the aquifer according to the fiver discharge and the water need. This method enables a continuous water supply over the whole year. Generally, artificially recharged groundwater is better protected against pollution than surface water, and the delimitation of water protection zones makes it even more save.

  17. Artificial heart for humanoid robot

    Science.gov (United States)

    Potnuru, Akshay; Wu, Lianjun; Tadesse, Yonas

    2014-03-01

    A soft robotic device inspired by the pumping action of a biological heart is presented in this study. Developing artificial heart to a humanoid robot enables us to make a better biomedical device for ultimate use in humans. As technology continues to become more advanced, the methods in which we implement high performance and biomimetic artificial organs is getting nearer each day. In this paper, we present the design and development of a soft artificial heart that can be used in a humanoid robot and simulate the functions of a human heart using shape memory alloy technology. The robotic heart is designed to pump a blood-like fluid to parts of the robot such as the face to simulate someone blushing or when someone is angry by the use of elastomeric substrates and certain features for the transport of fluids.

  18. [Implantation of the artificial retina].

    Science.gov (United States)

    Yagi, T; Hayashida, Y

    1999-05-01

    In some degenerative retinal diseases, e.g., retinitis pigmentosa and age-related macular degeneration, the photoreceptors are destroyed to cause serious visual defects. Recent studies on blind human subjects revealed that a large number of ganglion cells remains intact and is capable of transmitting signals to the brain to evoke partial visual perception. This provided hope to compensate for the visual defects with retinal prostheses. The recent progress of microfabrication technique made it possible to implement the Vary Large Scale Integrated circuit, the artificial retina, which emulates a part of retinal function. The idea of implanting the artificial retina to the patients was proposed recently and experiments using animals have been put into practice. This article surveys the front line of the artificial retina implantation.

  19. Artificial sweeteners: safe or unsafe?

    Science.gov (United States)

    Qurrat-ul-Ain; Khan, Sohaib Ahmed

    2015-02-01

    Artificial sweeteners or intense sweeteners are sugar substitutes that are used as an alternative to table sugar. They are many times sweeter than natural sugar and as they contain no calories, they may be used to control weight and obesity. Extensive scientific research has demonstrated the safety of the six low-calorie sweeteners currently approved for use in foods in the U.S. and Europe (stevia, acesulfame-K, aspartame, neotame, saccharin and sucralose), if taken in acceptable quantities daily. There is some ongoing debate over whether artificial sweetener usage poses a health threat .This review article aims to cover thehealth benefits, and risks, of consuming artificial sweeteners, and discusses natural sweeteners which can be used as alternatives. PMID:25842566

  20. Computational aerodynamics and artificial intelligence

    Science.gov (United States)

    Mehta, U. B.; Kutler, P.

    1984-01-01

    The general principles of artificial intelligence are reviewed and speculations are made concerning how knowledge based systems can accelerate the process of acquiring new knowledge in aerodynamics, how computational fluid dynamics may use expert systems, and how expert systems may speed the design and development process. In addition, the anatomy of an idealized expert system called AERODYNAMICIST is discussed. Resource requirements for using artificial intelligence in computational fluid dynamics and aerodynamics are examined. Three main conclusions are presented. First, there are two related aspects of computational aerodynamics: reasoning and calculating. Second, a substantial portion of reasoning can be achieved with artificial intelligence. It offers the opportunity of using computers as reasoning machines to set the stage for efficient calculating. Third, expert systems are likely to be new assets of institutions involved in aeronautics for various tasks of computational aerodynamics.

  1. Radio-ecological aspects in artificial groundwater recharge

    International Nuclear Information System (INIS)

    In increasing extent surface waters, especially those of rivers and streams, are contaminated by radionuclides. Therefore it is necessary to investigate the possibility of impairement of the quality of artificially recharged groundwater and drinking water by radionuclides. Hazards for man are possible by drinking water, that was affected by waste and during exposition to air, as well as indirectly by irrigation water and the food chain. In a model calculation using realistic conditions the order of magnitude of these hazards for man by incorporation of radioactively contaminated artificially recharged drinking water are to be assessed. Here the parameters are discussed which must be considered in such an assessment. The model includes the use of river water for artificial recharge. All models and assessments assume the most unfavourable preconditions, which may lead to an impact to man. (orig.)

  2. Myoelectric Control of Artificial Limb by Quantum Information Processing

    CERN Document Server

    Siomau, Michael

    2013-01-01

    Precise and elegant coordination of a prosthesis across many degrees of freedom is highly desired for rehabilitation of people with limb deficiency. Processing the electrical neural signals, collected from the surface of the remnant muscles of the stump, is a common way to activate certain function of the artificial limb. Based on the assumption that there are distinguishable and repeatable signal patterns among different types of muscular activation, the problem of the prosthesis control reduces to the pattern recognition. Widely accepted classical methods for pattern recognition, however, can not provide simultaneous and proportional control of the artificial limb. Here we show that quantum information processing of the neural signals allows us to overcome above difficulties suggesting a very simple scheme for myoelectric control of artificial limb with advanced functionalities.

  3. Agent communication and artificial institutions

    OpenAIRE

    Fornara, Nicoletta; Viganò, Francesco; Colombetti, Marco

    2011-01-01

    In this paper we propose an application-independent model for the definition of artificial institutions that can be used to define open multi-agent systems. Such a model of institutional reality makes us able also to define an objective and external semantics of a commitment-based Agent Communication Language (ACL). In particular we propose to regard an ACL as a set of conventions to act on a fragment of institutional reality, defined in the context of an artificial institution. Another c...

  4. Rewritable artificial magnetic charge ice

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. -L.; Xiao, Z. -L.; Snezhko, A.; Xu, J.; Ocola, L. E.; Divan, R.; Pearson, J. E.; Crabtree, G. W.; Kwok, W. -K.

    2016-05-19

    Artificial ices enable the study of geometrical frustration by design and through direct observation. However, it has proven difficult to achieve tailored long-range ordering of their diverse configurations, limiting both fundamental and applied research directions. We designed an artificial spin structure that produces a magnetic charge ice with tunable long-range ordering of eight different configurations. We also developed a technique to precisely manipulate the local magnetic charge states and demonstrate write-read-erase multifunctionality at room temperature. This globally reconfigurable and locally writable magnetic charge ice could provide a setting for designing magnetic monopole defects, tailoring magnonics, and controlling the properties of other two-dimensional materials.

  5. Artificial intelligence techniques in Prolog

    CERN Document Server

    Shoham, Yoav

    1993-01-01

    Artificial Intelligence Techniques in Prolog introduces the reader to the use of well-established algorithmic techniques in the field of artificial intelligence (AI), with Prolog as the implementation language. The techniques considered cover general areas such as search, rule-based systems, and truth maintenance, as well as constraint satisfaction and uncertainty management. Specific application domains such as temporal reasoning, machine learning, and natural language are also discussed.Comprised of 10 chapters, this book begins with an overview of Prolog, paying particular attention to Prol

  6. Artificial cells: prospects for biotechnology

    Science.gov (United States)

    Pohorille, Andrew; Deamer, David

    2002-01-01

    A variety of techniques can now be used to alter the genome of a cell. Although these techniques are very powerful, they have limitations related to cost and efficiency of scale. Artificial cells designed for specific applications combine properties of biological systems such as nanoscale efficiency, self-organization and adaptability at relatively low cost. Individual components needed for such structures have already been developed, and now the main challenge is to integrate them in functional microscopic compartments. It will then become possible to design and construct communities of artificial cells that can perform different tasks related to therapeutic and diagnostic applications.

  7. A Novel Approach for Treatment of an Unusual Presentation of Radicular Cysts Using Autologous Periosteum and Platelet-Rich Fibrin in Combination with Demineralized Freeze-Dried Bone Allograft

    Directory of Open Access Journals (Sweden)

    Veena A. Patil

    2013-01-01

    Full Text Available Radicular cysts are the most common cystic lesions affecting the jaws. They are most commonly found at the apices of the involved teeth. This condition is usually asymptomatic but can result in a slow-growth tumefaction in the affected region. The following case report presents the successful treatment of radicular cysts using autologous periosteum and platelet-rich fibrin with demineralized freeze-dried bone allograft.

  8. Influence of storage solution on enamel demineralization submitted to pH cycling Influência da solução de armazenagem na desmineralização do esmalte submetido à ciclagem de pH

    OpenAIRE

    Juliana Silva Moura; Lidiany Karla Azevedo Rodrigues; Altair Antoninha Del Bel Cury; Emilena Maria Castor Xisto Lima; Renata Matheus Cunha Rodrigues Garcia

    2004-01-01

    Extracted human teeth are frequently used for research or educational purposes. Therefore, it is necessary to store them in disinfectant solutions that do not alter dental structures. Thus, this study evaluated the influence of storage solution on enamel demineralization. For that purpose, sixty samples were divided into the following groups: enamel stored in formaldehyde (F1), stored in thymol (T1), stored in formaldehyde and submitted to pH cycling (F2), stored in thymol and submitted to pH...

  9. A clinical and radiological evaluation of the relative efficacy of demineralized freeze-dried bone allograft versus anorganic bovine bone xenograft in the treatment of human infrabony periodontal defects: A 6 months follow-up study

    OpenAIRE

    Vikram Blaggana; Amarjit Singh Gill; Anshu Blaggana

    2014-01-01

    Background: The ultimate goal of periodontal therapy entails regeneration of the periodontal tissues lost as a consequence of periodontitis. Predictable correction of vertical osseous defects has however posed as a constant therapeutic challenge. The aim of our present study is to evaluate the relative efficacy of demineralized freeze-dried bone allograft (DFDBA) vs anorganic bovine bone xenograft (ABBX) in the treatment of human infrabony periodontal defects. Materials and Methods: 15 patien...

  10. Octopus-like suction cups: from natural to artificial solutions.

    Science.gov (United States)

    Tramacere, F; Follador, M; Pugno, N M; Mazzolai, B

    2015-05-13

    Octopus suckers are able to attach to all nonporous surfaces and generate a very strong attachment force. The well-known attachment features of this animal result from the softness of the sucker tissues and the surface morphology of the portion of the sucker that is in contact with objects or substrates. Unlike artificial suction cups, octopus suckers are characterized by a series of radial grooves that increase the area subjected to pressure reduction during attachment. In this study, we constructed artificial suction cups with different surface geometries and tested their attachment performances using a pull-off setup. First, smooth suction cups were obtained for casting; then, sucker surfaces were engraved with a laser cutter. As expected, for all the tested cases, the engraving treatment enhanced the attachment performance of the elastomeric suction cups compared with that of the smooth versions. Moreover, the results indicated that the surface geometry with the best attachment performance was the geometry most similar to octopus sucker morphology. The results obtained in this work can be utilized to design artificial suction cups with higher wet attachment performance.

  11. Octopus-like suction cups: from natural to artificial solutions.

    Science.gov (United States)

    Tramacere, F; Follador, M; Pugno, N M; Mazzolai, B

    2015-06-01

    Octopus suckers are able to attach to all nonporous surfaces and generate a very strong attachment force. The well-known attachment features of this animal result from the softness of the sucker tissues and the surface morphology of the portion of the sucker that is in contact with objects or substrates. Unlike artificial suction cups, octopus suckers are characterized by a series of radial grooves that increase the area subjected to pressure reduction during attachment. In this study, we constructed artificial suction cups with different surface geometries and tested their attachment performances using a pull-off setup. First, smooth suction cups were obtained for casting; then, sucker surfaces were engraved with a laser cutter. As expected, for all the tested cases, the engraving treatment enhanced the attachment performance of the elastomeric suction cups compared with that of the smooth versions. Moreover, the results indicated that the surface geometry with the best attachment performance was the geometry most similar to octopus sucker morphology. The results obtained in this work can be utilized to design artificial suction cups with higher wet attachment performance. PMID:25970079

  12. Influence of storage solution on enamel demineralization submitted to pH cycling Influência da solução de armazenagem na desmineralização do esmalte submetido à ciclagem de pH

    Directory of Open Access Journals (Sweden)

    Juliana Silva Moura

    2004-09-01

    Full Text Available Extracted human teeth are frequently used for research or educational purposes. Therefore, it is necessary to store them in disinfectant solutions that do not alter dental structures. Thus, this study evaluated the influence of storage solution on enamel demineralization. For that purpose, sixty samples were divided into the following groups: enamel stored in formaldehyde (F1, stored in thymol (T1, stored in formaldehyde and submitted to pH cycling (F2, stored in thymol and submitted to pH cycling (T2. All samples were evaluated by cross-sectional microhardness analysis and had their percentage of mineral volume versus micrometer (integrated area determined. Differences between groups were found up to 30-µm depth from the enamel surface (p Dentes humanos extraídos são freqüentemente utilizados para propósitos educacionais ou de pesquisa. Desta forma, é necessário o armazenamento dos mesmos em soluções desinfetantes que não alterem a estrutura dental. Para tanto, sessenta espécimes foram divididos nos seguintes grupos: esmalte armazenado em formol (F1, armazenado em timol (T1, armazenado em formol e submetido à ciclagem de pH (F2 e armazenado em timol e submetido à ciclagem de pH (T2, sendo avaliados por meio de análise de microdureza longitudinal e tiveram a porcentagem de volume mineral pro micrômetro determinada. Diferenças entre os grupos foram encontradas até a profundidade de 30µm da superfície do esmalte (p<0,05, onde o grupo mais desmineralizado era T2. Foi concluído que a solução de armazenagem influenciou na reação do substrato dental a um desafio cariogênico, sugerindo que o formaldeído pode aumentar a resistência do esmalte à desmineralização promovida pelo modelo de ciclagem de pH, quando comparado à desmineralização ocorrida no esmalte armazenado em timol.

  13. Influence of stains on lesion contrast in the pits and fissures of tooth occlusal surfaces from 800-1600-nm

    Science.gov (United States)

    Almaz, Elias C.; Simon, Jacob C.; Fried, Daniel; Darling, Cynthia L.

    2016-02-01

    For over one hundred years, x-rays have served as a cornerstone of dentistry. Dental radiographic imaging technologies have constantly improved, however, detecting occlusal lesions remains as one of the greatest challenges due to the low sensitivity of radiographs and the overlap of enamel. Once detected, occlusal lesions have penetrated far into the dentin, necessitating invasive restorative treatment. The adoption of near-infrared (NIR) systems in dentistry introduces the potential for early detection of occlusal lesions. Commercially available NIR systems for intra-oral applications currently operate near 800-nm; however, extrinsic stains may interfere with the detection of demineralization of the underlying enamel surface. Higher wavelengths such as 1300-nm render stains nearly transparent and enhances the contrast of sound enamel to demineralized enamel. This novel finding promotes minimally invasive dentistry and allows oral health professionals the ability to detect, image, track, and monitor early lesions without repeated exposure to ionizing radiation nor invasive treatment.

  14. Generation of tactile maps for artificial skin.

    Directory of Open Access Journals (Sweden)

    Simon McGregor

    Full Text Available Prior research has shown that representations of retinal surfaces can be learned from the intrinsic structure of visual sensory data in neural simulations, in robots, as well as by animals. Furthermore, representations of cochlear (frequency surfaces can be learned from auditory data in neural simulations. Advances in hardware technology have allowed the development of artificial skin for robots, realising a new sensory modality which differs in important respects from vision and audition in its sensorimotor characteristics. This provides an opportunity to further investigate ordered sensory map formation using computational tools. We show that it is possible to learn representations of non-trivial tactile surfaces, which require topologically and geometrically involved three-dimensional embeddings. Our method automatically constructs a somatotopic map corresponding to the configuration of tactile sensors on a rigid body, using only intrinsic properties of the tactile data. The additional complexities involved in processing the tactile modality require the development of a novel multi-dimensional scaling algorithm. This algorithm, ANISOMAP, extends previous methods and outperforms them, producing high-quality reconstructions of tactile surfaces in both simulation and hardware tests. In addition, the reconstruction turns out to be robust to unanticipated hardware failure.

  15. Making Artificial Seawater More Natural

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Marine fish will die if placed in fresh water and they cannot live in simple salt water. Instead, they need water that contains a mixture of different ingredients, as found in natural seawater. Conventional methods of making artificial seawater have shortcomings, because the water so achieved is only composed of mineral elements and lacks organic components similar to those in natural seawater.

  16. Artificial Intelligence Assists Ultrasonic Inspection

    Science.gov (United States)

    Schaefer, Lloyd A.; Willenberg, James D.

    1992-01-01

    Subtle indications of flaws extracted from ultrasonic waveforms. Ultrasonic-inspection system uses artificial intelligence to help in identification of hidden flaws in electron-beam-welded castings. System involves application of flaw-classification logic to analysis of ultrasonic waveforms.

  17. Artificial Video for Video Analysis

    Science.gov (United States)

    Gallis, Michael R.

    2010-01-01

    This paper discusses the use of video analysis software and computer-generated animations for student activities. The use of artificial video affords the opportunity for students to study phenomena for which a real video may not be easy or even possible to procure, using analysis software with which the students are already familiar. We will…

  18. Artificial neural networks in medicine

    Energy Technology Data Exchange (ETDEWEB)

    Keller, P.E.

    1994-07-01

    This Technology Brief provides an overview of artificial neural networks (ANN). A definition and explanation of an ANN is given and situations in which an ANN is used are described. ANN applications to medicine specifically are then explored and the areas in which it is currently being used are discussed. Included are medical diagnostic aides, biochemical analysis, medical image analysis and drug development.

  19. Artificial-Satellite-Analysis Program

    Science.gov (United States)

    Kwok, Johnny H.

    1989-01-01

    Artificial Satellite Analysis Program (ASAP) is general orbit-predicting computer program incorporating sufficient orbit-modeling accuracy for design and planning of missions and analysis of maneuvers. Suitable for study of planetary-orbit missions with spacecraft trajectories of reconnaissance (flyby) and exploratory (mapping) nature. Not written for specific mission and intended use for almost any planetary orbiting mission. Written in FORTRAN 77.

  20. GC护牙素与氟保护漆在正畸治疗中抑制牙釉质脱矿的临床效果比较%GC Tooth Mousse Versus Fluor Protector in Inhibiting Enamel Demineral-ization in Orthodontic Treatment

    Institute of Scientific and Technical Information of China (English)

    徐晓静

    2015-01-01

    目的:探究GC护牙素与氟保护漆在正畸治疗中抑制牙釉质脱矿的临床效果。方法整群选取自2012年1月-2014年9月来该院接受正畸治疗的171例(3930颗牙)患者为该次研究对象,±据随机平行对照法将其随机分成三组,其中A组57例,1302颗牙,于正畸治疗中以对右侧牙齿行相似口味牙膏处理的患者为对照组,以应用GC护牙素对左侧牙齿进行处理的患者为护牙素组;B组57例,1293颗牙,以左侧牙齿行氟保护漆处理的患者为氟保护漆组,以右侧牙齿行釉质粘接剂A液处理的患者为对照组;C组57例,1335颗牙,对左侧牙齿行GC护牙素处理者为护牙素组,对右侧牙齿行氟保护漆处理者为氟保护漆组,对比各组牙釉质脱矿状况。结果A组中护牙素组釉质脱矿指数增加值(0.070±0.030)vs(0.097±0.018)较对照组低(P0.05)。结论在正畸治疗中,GC护牙素与氟保护漆均具有牙釉质脱矿抑制作用,临床上应引起足够重视。%Objective To explore the clinical effect of GC tooth mousse and fluor protector inhibiting enamel demineralization in orthodontic treatment. Methods 171 patients (3930 teeth) who received orthodontic treatment in our hospital between January 2012 and September 2014 were selected as the research object and divided, according to randomized parallel-group controlled method, into three groups, group A (57 patients , 1302 teeth), groups ( 57 patients, 1293 teeth), groups C (57 teeth, 1335 teeth). In the group A, patients whose teeth on right side received similar taste toothpaste processing were selected as the control group ,while those whose teeth on left side were treated with GC tooth mousse were selected as the tooth mousse group;in the group B, patients whose teeth on left side received fluor protector treatment were selected as the fluor protector group, while those whose teeth on right side were treated with enamel adhesive A; in the group C, patients

  1. Research on elastic modulus backcalculation of asphalt course using BP artificial neural network based on surface deflection basin of pavement%基于路表弯沉盆的BP人工神经网络反演沥青面层弹性模量研究

    Institute of Scientific and Technical Information of China (English)

    杨国良; 钟雯; 黄晓韵; 梁思敏; 何慧慧; 陈家驹

    2015-01-01

    Based on layered elastic theory,the elastic modulus of asphalt course in asphalt pavement was predicted using BP artificial neural network.According to the types of pavement structure in common use,the database of surface deflections with their corresponding structural parameters of asphalt course based on layered elastic theory was established.The elastic modulus backcalculation model of asphalt course in asphalt pavement was developed using BP artificial neural network to predict.The predictive results of asphalt course elastic modulus backcalculation using theoretical deflection basin and measured deflection basin indicate that the elastic modulus backcalculation model of asphalt course in asphalt pavement is of good predictive accuracy and reliability.It would provide the references with the elastic modulus backcalculation model of asphalt course to accurately and quickly estimate the conditions of asphalt course in asphalt pavement.%基于层状弹性体系理论,建立BP人工神经网络反演沥青路面沥青面层弹性模量预测模型,利用BP人工神经网络预测沥青路面沥青面层弹性模量.理论弯沉盆和实测弯沉盆反演沥青面层弹性模量的结果表明,建立的BP人工神经网络反演沥青路面沥青面层弹性模量模型具有良好的预测精度和可靠性,为评价沥青路面的沥青面层性能状况提供了参考.

  2. Surface stress, surface elasticity, and the size effect in surface segregation

    DEFF Research Database (Denmark)

    Schmid, M.; Hofer, W.; Varga, P.;

    1995-01-01

    Surface stress and surface elasticity of low-index fcc surfaces have been studied using effective-medium theory potentials. In addition to total-energy calculations giving stress components and elastic data for the surface as a whole, the use of artificial atoms with modified size allows us...... to probe the stress and elasticity of individual layers. This method of artificial atoms provides a direct way to study the contribution of atomic size to segregation in alloys as well as the driving force of reconstructions driven by surface stress. As an example, we give a qualitative explanation...

  3. Artificial Intelligence Databases: A Survey and Comparison.

    Science.gov (United States)

    Stern, David

    1990-01-01

    Identifies and describes online databases containing references to materials on artificial intelligence, robotics, and expert systems, and compares them in terms of scope and usage. Recommendations for conducting online searches on artificial intelligence and related fields are offered. (CLB)

  4. 21 CFR 886.3200 - Artificial eye.

    Science.gov (United States)

    2010-04-01

    ... OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a... inserted in a patient's eye socket anterior to an orbital implant, or the eviscerated eyeball, for...

  5. MOISTURE SORPTION IN ARTIFICIALLY AGED WOOD-PLASTIC COMPOSITES

    Directory of Open Access Journals (Sweden)

    B. Kristoffer Segerholm,

    2012-01-01

    Full Text Available Moisture sorption in wood-plastic composites (WPCs affects their durability and dimensional stability. In certain outdoor exposures, the moisture properties of WPCs are altered due to e.g. cracks induced by swelling and shrinkage of the components, as well as UV degradation or biological attack. The aim of this work was to study the effect of different artificial ageing routes on the moisture sorption properties of WPCs. Extruded WPCs were prepared with either unmodified or acetylated wood and recycled high-density polyethylene (HDPE. The WPC samples were artificially aged involving water soaking, artificial weathering, and white- or brown-rot decay in different combinations. After the ageing, the samples were conditioned in either 65% or 90% relative humidity (RH until equilibrium moisture content was reached. A dynamic moisture sorption analyzer was used to monitor the sorption rate of samples subjected to a climate change from 65% to 90% RH. Scanning electron microscopy was used to study the surface morphology of the aged composites. Results showed that the artificial weathering caused cracking of the HDPE matrix at the composite surface, as well as a wood-matrix debonding, resulting in an increased moisture sorption rate. The WPC samples subjected to white-rot decay showed the highest moisture sorption rate.

  6. Elastic moduli of untreated, demineralized and deproteinized cortical bone: validation of a theoretical model of bone as an interpenetrating composite material.

    Science.gov (United States)

    Hamed, E; Novitskaya, E; Li, J; Chen, P-Y; Jasiuk, I; McKittrick, J

    2012-03-01

    A theoretical experimentally based multi-scale model of the elastic response of cortical bone is presented. It portrays the hierarchical structure of bone as a composite with interpenetrating biopolymers (collagen and non-collagenous proteins) and minerals (hydroxyapatite), together with void spaces (porosity). The model involves a bottom-up approach and employs micromechanics and classical lamination theories of composite materials. Experiments on cortical bone samples from bovine femur include completely demineralized and deproteinized bones as well as untreated bone samples. Porosity and microstructure are characterized using optical and scanning electron microscopy, and micro-computed tomography. Compression testing is used to measure longitudinal and transverse elastic moduli of all three bone types. The characterization of structure and properties of these three bone states provides a deeper understanding of the contributions of the individual components of bone to its elastic response and allows fine tuning of modeling assumptions. Very good agreement is found between theoretical modeling and compression testing results, confirming the validity of the interpretation of bone as an interpenetrating composite material.

  7. Effects of Fuji Ⅶ on preventing enamel demineralization during orthodontic treatment%FujiⅦ预防正畸患者釉质脱矿的临床评价

    Institute of Scientific and Technical Information of China (English)

    贾亚梅; Hien C Ngo; 徐焱; 候旭; 孙新华

    2013-01-01

    Objective To investigate the effectiveness of Fuji Ⅶ on preventing enamel demineralization around brackets during orthodontic treatment.Methods 30 patients (11 13 years old,10 male and 20 female) receiving fixed orthodontic treatment in Jilin university were randomly selected.Contralateral teeth were also randomly divided into experimental and control group.After bonding,Fuji Ⅶ were applied within 1.5 mm range around lateral incisors,canines,first premolarandsecond premolar brackets of experimental group.The control group received no applicatior.Digital camera images of teeth were takenimmediately,after one month,three months,six months and nine months after bonding to observe the possible demineralization.EDI index was also used to record enamel demineralization situation of different stages.Pair t test was performed to analyze the data(SPSS11.5 software package).Results The average enamel decalcification index of the control sidewas 0.256,0.358,0.394,0.350 respectively for 1 month,3 months,6 months and 9 months after treatment,while the index for experimental sidewas 0.194,0.222,0.186,0.144 respectively for the corresponding time.The data indicated a significant lower EDI in the experimental group than in the control side (P<0.05).The enameldemineralizations in experimental side were much less severe than control side.Conclusions Fuji Ⅶ can prevent enamel demineralization around brackets in some extent,yet not absolutely prevent the procedure.%目的 评价并探讨FujiⅦ预防固定正畸过程中釉质脱矿的有效性.方法 选择于吉林大学口腔医院正畸科就诊并需戴用固定矫治器的患者30例,男10例,女20例,年龄范围11~13岁.采用投币法将所需观察的牙齿随机分为实验侧与对照侧.在正畸托槽粘结后于实验侧的上颌侧切牙、尖牙、第一双尖牙/第二双尖牙托槽周围1.5mm范围处涂布FujiⅦ,对照侧不涂.于初戴、矫治后1、3、6及9个月时应用专业数码相机拍摄

  8. Preventive effect of fluoride toothpaste on enamel demineralization in fixed appliance treatment%含氟牙膏对固定矫治中牙釉质脱矿预防效果的研究

    Institute of Scientific and Technical Information of China (English)

    李一妹; 厉松; 张丁

    2015-01-01

    目的:探讨含氟牙膏在正畸固定矫治中对预防牙釉质脱矿的作用。方法本实验通过常规口腔卫生宣教指导接受固定矫治器治疗的患者分别使用不同种牙膏刷牙,将患者随机分为氟化物组和对照组,氟化物组采用含氟牙膏刷牙,对照组采用不含氟牙膏刷牙,应用时间平均18个月。分别比较矫治前后两组患者及被观察牙齿牙釉质脱矿发病率和脱矿程度,判断含氟牙膏在固定矫治中对牙釉质脱矿的预防效果。结果在正畸固定矫治中,应用氟浓度为0.15%的含氟牙膏刷牙,可明显降低牙釉质脱矿的发病率,明显减少牙釉质3度脱矿的发生。结论0.15%含氟牙膏应用于固定矫治能够降低牙釉质脱矿的程度。%Objective To investigate the effect of fluoride toothpaste on the prevention of enamel demineralization in fixed appliance treatment. Methods The patients treated with fixed appliance under the instruction of regular oral hygiene education guidance were randomly divided into two groups,the fluoride application group and the control group. The fluoride application group used fluoride toothpaste while the control group used non-fluoridated toothpaste for an average period of eighteen months. The occurrence of tooth enamel demineralization and the extent of demineralization before and after treatment in the two groups were compared in order to identify the effect of fluoride toothpaste on the prevention of enamel demineralization during fixed appliance treatment. Results During the fixed orthodontic treatment, brushing the teeth with 0. 15% fluoride toothpaste can significantly reduce the incidence of enamel demineralization, and also can significantly reduce the degree of enamel emineralization.

  9. Introduction to Concepts in Artificial Neural Networks

    Science.gov (United States)

    Niebur, Dagmar

    1995-01-01

    This introduction to artificial neural networks summarizes some basic concepts of computational neuroscience and the resulting models of artificial neurons. The terminology of biological and artificial neurons, biological and machine learning and neural processing is introduced. The concepts of supervised and unsupervised learning are explained with examples from the power system area. Finally, a taxonomy of different types of neurons and different classes of artificial neural networks is presented.

  10. Artificial Excitation of Schumann Resonance with HAARP

    Science.gov (United States)

    Streltsov, A. V.; Chang, C. L.

    2014-12-01

    We report results from the experiment aimed at the artificial excitation of extremely-low-frequency (ELF) electromagnetic waves with frequencies corresponding to the frequency of Schumann resonance (typically, 7.5 - 8.0 Hz frequency range). Electromagnetic waves with these frequencies can form a standing pattern inside the spherical cavity formed by the surface of the earth and the ionosphere. In the experiment the ELF waves were excited by heating the ionosphere with X-mode HF electromagnetic waves generated by the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. The experiment demonstrates that heating of the ionosphere can excite relatively large-amplitude electromagnetic waves with frequencies in the range of the Schumann resonance, when the ionosphere has a strong F-layer and an electric field greater than 5 mV/m is present in the E-region.

  11. 渗透树脂治疗正畸后牙面脱矿2年临床稳定性观察%Stability of effect on the demineralized dental faces after Orthodontics treated by infi ltration resin for two year

    Institute of Scientific and Technical Information of China (English)

    陶波; 宁颖圆

    2015-01-01

    Objective To evaluate the stability of the effect on the demineralized dental faces (white spots) after orthodontics treated by infi itration resin. Methods 20 post-orthodontic patients with 8 maxillary anterior teeth showing signs of demineralization ( total 160 teeth) were enrolled in this study.All teeth were treated with infi itration resin .Standardized digital images were taken before, immediately after and 6,12,24 months after treatment.The images were analyzed using an image a-nalysis software. The size of the white spot lesion (W) and the whole tooth facial surface (T) were measured, and the W:T ratio(%)was calculated. Results During this period of two years following up,the W:T ratio of 6,12,24 months after treatment show no significant difference by Wilcoxon te-st (P>0.05) Conclusion During this period of two years following up,the effect of resin infiltration treatment for masking white spot lesion is stable. It is worth popularizing and applying on clinic.%目的:探讨爱康渗透树脂治疗正畸后牙面脱矿(白垩斑)的疗效稳定性。方法:选取已完成正畸治疗的前牙区釉质白垩斑患者20名,应用渗透树脂治疗。治疗后即刻和术后6个月、1年、2年分别拍摄数码照片。由另外两位医生判断有无颜色变化,并测量术前、术后白垩斑面积(W)及患牙唇面的面积(T),计算出W/T比值(%),评价其疗效稳定性。结果:随访两年,术后6个月、1年、2年间W/T比值经多样本的秩和检验,P>0.05,无统计学差异。结论:渗透树脂治疗后在2年观察期内颜色表现稳定,值得临床上推广应用。

  12. Artificial Intelligence and Its Importance in Education.

    Science.gov (United States)

    Tilmann, Martha J.

    Artificial intelligence, or the study of ideas that enable computers to be intelligent, is discussed in terms of what it is, what it has done, what it can do, and how it may affect the teaching of tomorrow. An extensive overview of artificial intelligence examines its goals and applications and types of artificial intelligence including (1) expert…

  13. Impact of Artificial Intelligence on Economic Theory

    OpenAIRE

    Tshilidzi Marwala

    2015-01-01

    Artificial intelligence has impacted many aspects of human life. This paper studies the impact of artificial intelligence on economic theory. In particular we study the impact of artificial intelligence on the theory of bounded rationality, efficient market hypothesis and prospect theory.

  14. Artificial Intelligence in Canada: A Review

    OpenAIRE

    Mccalla, Gordon; Cercone, Nick

    1984-01-01

    Canadians have made many contributions to artificial intelligence over the years. This article presents a summary of current research in artificial intelligence in Canada and acquaints readers with the Canadian organization for artificial intelligence -- the Canadian Society for the Computational Studies of Intelligence / Societe Canadienne pour l' Etude de l'Intelligence par Ordinateur (CSCSI/ SCEIO).

  15. Artificial Ant Species on Solving Optimization Problems

    OpenAIRE

    Pintea, Camelia-M.

    2013-01-01

    During the last years several ant-based techniques were involved to solve hard and complex optimization problems. The current paper is a short study about the influence of artificial ant species in solving optimization problems. There are studied the artificial Pharaoh Ants, Lasius Niger and also artificial ants with no special specificity used commonly in Ant Colony Optimization.

  16. Artificial delta growth

    Science.gov (United States)

    Mikeš, Daniel

    2010-05-01

    A deltaic sedimentary system has a point source; sediment is carried over the delta plain by distributary channels away from the point source and deposited at the delta front by distributary mouth bars. The established methods to describe such a sedimentary system are "bedding analysis", "facies analysis", and "basin analysis". We shall call the ambient conditions "input" and the rock record "output". There exist a number of methods to deduce input from output, e.g. "Sequence stratigraphy" (a.o. Vail et al. 1977, Catuneanu et al. 2009), "Shoreline trajectory" (a.o. Helland-Hansen & Martinsen 1996, Helland-Hansen & Hampson 2009) on the one hand and the complex use of established techniques on the other (a.o. Miall & Miall 2001, Miall & Miall 2002). None of these deductive methods seems to be sufficient. I claim that the common errors in all these attempts are the following: (1) a sedimentary system is four-dimensional (3+1) and a lesser dimensional analysis is insufficient; (2) a sedimentary system is complex and any empirical/deductive analysis is non-unique. The proper approach to the problem is therefore the theoretical/inductive analysis. To that end we performed six scenarios of a scaled version of a passive margin delta in a flume tank. The scenarios have identical stepwise tectonic subsidence and semi-cyclic sealevel, but different supply curves, i.e. supply is: constant, highly-frequent, proportional to sealevel, inversely proportional to sealevel, lagging to sealevel, ahead of sealevel. The preliminary results are indicative. Lobe-switching occurs frequently and hence locally sedimentation occurs shortly and hiatuses are substantial; therefore events in 2D (+1) cross-sections don't correlate temporally. The number of sedimentary cycles disequals the number of sealevel cycles. Lobe-switching and stepwise tectonic subsidence cause onlap/transgression. Erosional unconformities are local diachronous events, whereas maximum flooding surfaces are regional

  17. Application requirements of artificial muscles for swimming robots

    Science.gov (United States)

    Kerrebrock, Peter A.; Anderson, Jamie M.; Parry, Joel R.

    2001-07-01

    In the near future, we will find biomimetic undersea robots in the forefront of unmanned underwater applications due to their ability to operate in new, challenging, and highly dynamic environments such as rivers, surf, and turbulent pipe flow. In particular, fish-like vehicles (FLVs) have emerged as a viable technology for highly maneuverable, efficient and stealthy platforms. Attempts to produce fish-like motion using conventional mechanical means have proven difficult, however, resulting in complex and unreliable machines, especially when compared to the simplicity of a rotating propeller and conventional control surfaces. To take full advantage of fish-like propulsion, a new actuation strategy is needed, to which artificial muscles may be uniquely suited. Some artificial muscles are made of materials with relatively low specific gravity (compared to conventional mechanical systems), and so will be nearly neutrally buoyant in underwater applications. This is critical in FLV actuation, as correct longitudinal mass distribution is required to avoid stability problems. Additionally, some artificial muscle formulations require water, sometimes including an electrolyte, which is easily provided in underwater applications. Finally, for stealthy applications, artificial muscles may provide acoustically quiet actuation due to their suppleness and reduced number of interconnecting mechanical components. In this paper, we suggest artificial muscle-based actuation strategies for FLVs, based on experience with the Vorticity Control Unmanned Undersea Vehicle (VCUUV), an eight-foot long autonomous robotic tuna. Recently developed artificial muscles are surveyed and evaluated as to their suitability for fish-like propulsion. Requirements for force, power, and strain as well as implementation issues are discussed.

  18. Economic reasoning and artificial intelligence.

    Science.gov (United States)

    Parkes, David C; Wellman, Michael P

    2015-07-17

    The field of artificial intelligence (AI) strives to build rational agents capable of perceiving the world around them and taking actions to advance specified goals. Put another way, AI researchers aim to construct a synthetic homo economicus, the mythical perfectly rational agent of neoclassical economics. We review progress toward creating this new species of machine, machina economicus, and discuss some challenges in designing AIs that can reason effectively in economic contexts. Supposing that AI succeeds in this quest, or at least comes close enough that it is useful to think about AIs in rationalistic terms, we ask how to design the rules of interaction in multi-agent systems that come to represent an economy of AIs. Theories of normative design from economics may prove more relevant for artificial agents than human agents, with AIs that better respect idealized assumptions of rationality than people, interacting through novel rules and incentive systems quite distinct from those tailored for people.

  19. Computer automation and artificial intelligence

    International Nuclear Information System (INIS)

    Rapid advances in computing, resulting from micro chip revolution has increased its application manifold particularly for computer automation. Yet the level of automation available, has limited its application to more complex and dynamic systems which require an intelligent computer control. In this paper a review of Artificial intelligence techniques used to augment automation is presented. The current sequential processing approach usually adopted in artificial intelligence has succeeded in emulating the symbolic processing part of intelligence, but the processing power required to get more elusive aspects of intelligence leads towards parallel processing. An overview of parallel processing with emphasis on transputer is also provided. A Fuzzy knowledge based controller for amination drug delivery in muscle relaxant anesthesia on transputer is described. 4 figs. (author)

  20. Economic reasoning and artificial intelligence.

    Science.gov (United States)

    Parkes, David C; Wellman, Michael P

    2015-07-17

    The field of artificial intelligence (AI) strives to build rational agents capable of perceiving the world around them and taking actions to advance specified goals. Put another way, AI researchers aim to construct a synthetic homo economicus, the mythical perfectly rational agent of neoclassical economics. We review progress toward creating this new species of machine, machina economicus, and discuss some challenges in designing AIs that can reason effectively in economic contexts. Supposing that AI succeeds in this quest, or at least comes close enough that it is useful to think about AIs in rationalistic terms, we ask how to design the rules of interaction in multi-agent systems that come to represent an economy of AIs. Theories of normative design from economics may prove more relevant for artificial agents than human agents, with AIs that better respect idealized assumptions of rationality than people, interacting through novel rules and incentive systems quite distinct from those tailored for people. PMID:26185245

  1. Artificial Skin Ridges Enhance Local Tactile Shape Discrimination

    CERN Document Server

    Salehi, Saba; Ge, Shuzhi Sam; 10.3390/s110908626

    2011-01-01

    One of the fundamental requirements for an artificial hand to successfully grasp and manipulate an object is to be able to distinguish different objects' shapes and, more specifically, the objects' surface curvatures. In this study, we investigate the possibility of enhancing the curvature detection of embedded tactile sensors by proposing a ridged fingertip structure, simulating human fingerprints. In addition, a curvature detection approach based on machine learning methods is proposed to provide the embedded sensors with the ability to discriminate the surface curvature of different objects. For this purpose, a set of experiments were carried out to collect tactile signals from a 2 \\times 2 tactile sensor array, then the signals were processed and used for learning algorithms. To achieve the best possible performance for our machine learning approach, three different learning algorithms of Na\\"ive Bayes (NB), Artificial Neural Networks (ANN), and Support Vector Machines (SVM) were implemented and compared ...

  2. Bioengineering of Artificial Lymphoid Organs

    OpenAIRE

    Nosenko, M. A.; Drutskaya, M. S; M. M. Moisenovich; Nedospasov, S A

    2016-01-01

    This review addresses the issue of bioengineering of artificial lymphoid organs.Progress in this field may help to better understand the nature of the structure-function relations that exist in immune organs. Artifical lymphoid organs may also be advantageous in the therapy or correction of immunodefficiencies, autoimmune diseases, and cancer. The structural organization, development, and function of lymphoid tissue are analyzed with a focus on the role of intercellular contacts and on the cy...

  3. A Definition of Artificial Intelligence

    OpenAIRE

    Dobrev, Dimiter

    2012-01-01

    In this paper we offer a formal definition of Artificial Intelligence and this directly gives us an algorithm for construction of this object. Really, this algorithm is useless due to the combinatory explosion. The main innovation in our definition is that it does not include the knowledge as a part of the intelligence. So according to our definition a newly born baby also is an Intellect. Here we differs with Turing's definition which suggests that an Intellect is a person with knowledge gai...

  4. Formation of artificial ionospheric ducts

    OpenAIRE

    Milikh, G. M.; Papadopoulos, K.; Shroff, H; Chang, C. L.; Wallace, T; E. V. Mishin; Parrot, Michel; Berthelier, Jean-Jacques

    2008-01-01

    International audience It is well known that strong electron heating by a powerful HF-facility can lead to the formation of electron and ion density perturbations that stretch along the magnetic field line. Those density perturbations can serve as ducts for ELF waves, both of natural and artificial origin. This paper presents the first experimental evidence of plasma modifications associated with ion outflows due to HF heating. The experiments were conducted using the HAARP heater during t...

  5. Automated Scheduling Via Artificial Intelligence

    Science.gov (United States)

    Biefeld, Eric W.; Cooper, Lynne P.

    1991-01-01

    Artificial-intelligence software that automates scheduling developed in Operations Mission Planner (OMP) research project. Software used in both generation of new schedules and modification of existing schedules in view of changes in tasks and/or available resources. Approach based on iterative refinement. Although project focused upon scheduling of operations of scientific instruments and other equipment aboard spacecraft, also applicable to such terrestrial problems as scheduling production in factory.

  6. Artificial Sweeteners versus Natural Sweeteners

    OpenAIRE

    Neacsu, N.A.; Madar, A.

    2014-01-01

    Carbohydrates are an important dietary nutrient which is mostly used to supply energy to the body, as well as a carbon source for synthesis of other needed chemicals. In addition, mono- and disaccharides are craved because of their sweetness. We present different types of sweeteners, which are the basic contents of foods which we consume every day and are demonstrated the positive and negative effects of natural and artificial sweeteners.

  7. Worldwide variations in artificial skyglow

    OpenAIRE

    Kyba, Christopher C. M.; Kai Pong Tong; Jonathan Bennie; Ignacio Birriel; Jennifer J. Birriel; Andrew Cool; Arne Danielsen; Davies, Thomas W; den Outer, Peter N.; William Edwards; Rainer Ehlert; Fabio Falchi; Jürgen Fischer; Andrea Giacomelli; Francesco Giubbilini

    2015-01-01

    Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope, and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artifi...

  8. Artificial color perception using microwaves

    CERN Document Server

    Choudhury, Debesh

    2013-01-01

    We report the feasibility of artificial color perception under microwave illumination using a standard microwave source and an antenna. We have sensed transmitted microwave power through color objects and have distinguished the colors by analyzing the sensed transmitted power. Experiments are carried out using a Gunn diode as the microwave source, some colored liquids as the objects and a microwave diode as the detector. Results are presented which open up an unusual but new way of perceiving colors using microwaves.

  9. Artificial Sweeteners versus Natural Sweeteners

    Directory of Open Access Journals (Sweden)

    Neacsu, N.A.

    2014-06-01

    Full Text Available Carbohydrates are an important dietary nutrient which is mostly used to supply energy to the body, as well as a carbon source for synthesis of other needed chemicals. In addition, mono- and disaccharides are craved because of their sweetness. We present different types of sweeteners, which are the basic contents of foods which we consume every day and are demonstrated the positive and negative effects of natural and artificial sweeteners.

  10. Artificial life: The coming evolution

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.D. (Los Alamos National Lab., NM (USA) Santa Fe Inst., NM (USA)); Belin, A.d' A. (Shute, Mihaly, and Weinberger, Santa Fe, NM (USA))

    1990-01-01

    Within fifty to a hundred years a new class of organisms is likely to emerge. These organisms will be artificial in the sense that they will originally be designed by humans. However, they will reproduce, and will evolve into something other than their initial form; they will be alive'' under any reasonable definition of the word. These organisms will evolve in a fundamentally different manner than contemporary biological organisms, since their reproduction will be under at least partial conscious control, giving it a Lamarckian component. The pace of evolutionary change consequently will be extremely rapid. The advent of artificial life will be the most significant historical event since the emergence of human beings. The impact on humanity and the biosphere could be enormous, larger than the industrial revolution, nuclear weapons, or environmental pollution. We must take steps now to shape the emergence of artificial organisms; they have potential to be either the ugliest terrestrial disaster, or the most beautiful creation of humanity. 22 refs., 3 figs.

  11. Beller Lecture: Artificial Ferroic Systems

    Science.gov (United States)

    Heyderman, Laura

    In artificial ferroic systems, novel functionality is engineered through the combination of structured ferroic materials and the control of the interactions between the different components. I will present two classes of these systems, beginning with hybrid mesoscopic structures incorporating two different ferromagnetic layers whose static and dynamic behaviour result from the mutual imprint of the magnetic domain configurations. Here we have demonstrated a new vortex core reversal mechanism, which occurs when it is displaced across domain boundaries with a magnetic field. I will then describe our progress on artificial spin ice, consisting of arrays of dipolar-coupled nanomagnets arranged in frustrated geometries. We have employed photoemission electron microscopy to observe the behaviour of emergent magnetic monopoles in an array of nanomagnets placed on the kagome lattice. We have also created artificial spin ice with fluctuating magnetic moments and observed the evolution of magnetic configurations with time. This has provided a means to study relaxation processes with a controlled route to the lowest-energy state. Recently, we have demonstrated with muon spin relaxation that these magnetic metamaterials can support thermodynamic phase transitions, and future directions include the incorporation of novel magnetic materials such as ultrathin magnetic films, the investigation of 3D structures, as well as the implementation of x-ray resonant magnetic scattering to study magnetic correlations in smaller nanomagnets and at faster timescales

  12. Methods for histochemical demonstration of vascular structures at the muscle-bone interface from cryostate sections of demineralized tissue

    DEFF Research Database (Denmark)

    Kirkeby, S

    1981-01-01

    In tissue decalcified with MgNa2EDTA at a neutral pH activity for ATPase can used be for demonstration of the vascular structures at the muscle-bone interface. The GOMORI method for alkaline phosphatase is only of value, when fresh unfixed tissue is to be examined. The azo-dye method for alkaline...... phosphatase failed to give satisfactory results, and so did the alpha-amylase PAS method. 5'-nucleotidase activity is present in both capillaries and in cells lining the surfaces of bones, while larger blood vessels are poorly stained....

  13. Hydrogeological Methods for Assessing Feasibility of Artificial Recharge

    Science.gov (United States)

    Kim, Y.; Koo, M.; Lee, K.; Moon, D.; Barry, J. M.

    2009-12-01

    This study presents the hydrogeological methods to assess the feasibility of artificial recharge in Jeju Island, Korea for securing both sustainable groundwater resources and severe floods. Jeju-friendly Aquifer Recharge Technology (J-ART) in this study is developing by capturing ephemeral stream water with no interference in the environments such as natural recharge or eco-system, storing the flood water in the reservoirs, recharging it through designed borehole after appropriate water treatment, and then making it to be used at down-gradient production wells. Many hydrogeological methods, including physico-chemical surface water and groundwater monitoring, geophysical survey, stable isotope analysis, and groundwater modeling have been employed to predict and assess the artificially recharged surface waters flow and circulation between recharge area and discharge area. In the study of physico-chemical water monitoring survey, the analyses of surface water level and velocity, of water qualities including turbidity, and of suspended soil settling velocity were performed. For understanding subsurface hydrogeologic characteristics the injection test was executed and the results are 118-336 m2/day of transmissivity and 4,367-11,032 m3/day of the maximum intake water capacity. Characterizing groundwater flow from recharge area to discharge area should be achieved to assess the efficiency of J-ART. The resistivity logging was carried out to predict water flow in unsaturated zone during artificial recharge based on the inverse modeling and resistivity change patterns. Stable isotopes of deuterium and oxygen-18 of surface waters and groundwaters have been determined to interpret mixing and flow in groundwaters impacted by artificial recharge. A numerical model simulating groundwater flow and heat transport to assess feasibility of artificial recharge has been developed using the hydraulic properties of aquifers, groundwater levels, borehole temperatures, and meteorological

  14. A modified pH-cycling model to evaluate fluoride effect on enamel demineralization Modelo de ciclagens de pH para avaliar o efeito do fluoreto na desmineralização do esmalte

    Directory of Open Access Journals (Sweden)

    Rosane Maria Orth Argenta

    2003-09-01

    Full Text Available Since in vitro pH-cycling models are widely used to study dental caries, they should allow evaluations of fluoride effect on early stages of caries development. Therefore, acid etching on enamel surface must be avoided, enabling surface microhardness (SMH analysis. In the present study, the pH-cycling model originally described by Featherstone et al.9 (1986 was modified to preserve the enamel surface and to produce early carious lesions that could be evaluated using SMH and cross-sectional microhardness (CSMH measurements. In order to validate this modified model, a dose-response evaluation with fluoride was made. Human enamel blocks with known SMH were submitted to such regimen with the following treatments: distilled deionized water (DDW; control and solutions containing 70, 140 and 280 ppm F. Data from %SMH change and deltaZ (mineral loss showed a statistically significant negative correlation between F concentration in treatment solutions and mineral loss. In conclusion, the modified pH-cycling model allowed the evaluation of changes on the outermost enamel layer during caries development, and a dose-response effect of fluoride reducing enamel demineralization was observed.Considerando que os modelos de ciclagens de pH são amplamente usados para estudar a cárie dental, eles deveriam possibilitar a avaliação do efeito do fluoreto nos estágios iniciais do desenvolvimento da cárie. Desse modo, o ataque ácido erosivo na superfície do esmalte deve ser evitado, possibilitando a análise da microdureza de superfície (MDS. No presente estudo, o modelo de ciclagens de pH descrito por Featherstone et al.9 (1986 foi modificado para preservar a superfície do esmalte e para produzir lesões iniciais que pudessem ser avaliadas usando MDS e microdureza do esmalte seccionado longitudinalmente. Para validar esse modelo modificado, uma avaliação dose-resposta a fluoreto foi feita. Blocos de esmalte dental humano de MDS conhecida foram submetidos a

  15. A review on methodology of artificial roughness used in duct of solar air heaters

    Energy Technology Data Exchange (ETDEWEB)

    Bhushan, Brij; Singh, Ranjit [Department of Mechanical Engineering, Beant College of Engineering and Technology, Gurdaspur 143521, Punjab (India)

    2010-01-15

    In order to enhance rate of heat transfer to flowing air in the duct of a solar air heater, artificially roughened surface of absorber plate is considered to be an effective technique. Investigators reported various roughness geometries in literature for studying heat transfer and friction characteristics of an artificially roughened duct of solar air heaters. In the present paper an attempt has been made to categorize and review the reported roughness geometries used for creating artificial roughness. Heat transfer coefficient and friction factor correlations developed by various investigators for roughened ducts of solar air heaters have also been reported in the present paper. (author)

  16. Improved management of SG BD demineralizer for reduced generation of low-level radioactive spent resin in Korean nuclear power plants

    International Nuclear Information System (INIS)

    Most nuclear power plants in Korea have adopted Ethanolamine(ETA) as a secondary pH control agent to increase the pH at the liquid phase, which may reduce the corrosion in steam generator tubes and moisture separator/reheat system. Along with its beneficial effect of SG protection from corrosion and degradation, the replacement of ammonia with ETA causes the increased generation of spent resin and the reduced run time of demineralizer in steam generator blowdown(SG BD) system. The composition ratio of cation- to anion- exchange resin in SG BD mixed bed should be increased in the ETA chemistry environment to meet the ratio of cation to anion in the aqueous solution, which results in the simultaneous exhaustion of cation and anion exchange resins. The utilization rate of mixed bed is greatest at the cation-to-anion ratio of 95:1 on the theoretical equivalent basis in the solution, but practically highest at that of 22:1 due to the possible inhomogeneous distribution of cation and anion exchange resins in SG BD bed. The run time of the bed could be extended by 30% such that, at that much, the purchase cost of new resin is saved and the production rate of spent resin is reduced. The guideline on the replacement of resin in SG BD bed is not necessary to secure the removal of radioactive particles without the leakage of the primary coolant into the secondary side since all the radioactive ions can be eliminated by SG BD bed with the sufficient time. They are retained during more than one month after their ingress into the SG BD bed without leakage. With the reduced replacement, thus, the SG BD spent resin that comprises 65% of low-level radioactive solid waste can be much cut down

  17. Climbing robot actuated by meso-hydraulic artificial muscles

    Science.gov (United States)

    Bryant, Matthew; Fitzgerald, Jason; Miller, Samuel; Saltzman, Jonah; Kim, Sangkyu; Lin, Yong; Garcia, Ephrahim

    2014-03-01

    This paper presents the design, construction, experimental characterization, and system testing of a legged, wall-climbing robot actuated by meso-scale hydraulic artificial muscles. While small wall-climbing robots have seen increased research attention in recent years, most authors have primarily focused on designs for the gripping and adhesion of the robot to the wall, while using only standard DC servo-motors for actuation. This project seeks to explore and demonstrate a different actuation mechanism that utilizes hydraulic artificial muscles. A four-limb climbing robot platform that includes a full closed-loop hydraulic power and control system, custom hydraulic artificial muscles for actuation, an on-board microcontroller and RF receiver for control, and compliant claws with integrated sensing for gripping a variety of wall surfaces has been constructed and is currently being tested to investigate this actuation method. On-board power consumption data-logging during climbing operation, analysis of the robot kinematics and climbing behavior, and artificial muscle force-displacement characterization are presented to investigate and this actuation method.

  18. Review of Artificial Abrasion Test Methods for PV Module Technology

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Muller, Matt T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Simpson, Lin J. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-08-01

    This review is intended to identify the method or methods--and the basic details of those methods--that might be used to develop an artificial abrasion test. Methods used in the PV literature were compared with their closest implementation in existing standards. Also, meetings of the International PV Quality Assurance Task Force Task Group 12-3 (TG12-3, which is concerned with coated glass) were used to identify established test methods. Feedback from the group, which included many of the authors from the PV literature, included insights not explored within the literature itself. The combined experience and examples from the literature are intended to provide an assessment of the present industry practices and an informed path forward. Recommendations toward artificial abrasion test methods are then identified based on the experiences in the literature and feedback from the PV community. The review here is strictly focused on abrasion. Assessment methods, including optical performance (e.g., transmittance or reflectance), surface energy, and verification of chemical composition were not examined. Methods of artificially soiling PV modules or other specimens were not examined. The weathering of artificial or naturally soiled specimens (which may ultimately include combined temperature and humidity, thermal cycling and ultraviolet light) were also not examined. A sense of the purpose or application of an abrasion test method within the PV industry should, however, be evident from the literature.

  19. Initial Ecosystem Development in an Artificial Watershed

    Science.gov (United States)

    Huettl, R.; Koegel-Knabner, I.; Zeyer, J.

    2008-12-01

    Watersheds are often used as a base for ecosystem research. However, boundaries and inner structures of natural watersheds are often insufficiently known and have to be explored indirectly e.g. by means of geophysical methods. Therefore, important parts of the system often remain 'black boxes'. In addition, natural systems are characterized by huge complexity and heterogeneity. To overcome these disadvantages artificially created watersheds may play an important role in ecosystem research. They offer the chance to investigate systems with well defined boundary conditions and inner structures. Furthermore, artificial watersheds might be an important link between lysimeter research and investigations at the landscape scale. The artificial catchment "Chicken Creek" ('Huehnerwasser') is one of the world's largest man-made catchments for scientific purposes. It was established in 2005 with an area of 6 ha (450 m x 150 m) including a small lake. The site is located in the Eastern German lignite mining district near Cottbus, about 150 km southeast of Berlin. The watershed was constructed by Vattenfall Europe Mining AG as the operator of the still active lignite open-cast mine Welzow-South. Construction work was done by means of large mining machines in co-operation with the Brandenburg University of Technology at Cottbus. The inner structure of this new landscape element is relatively simple: A clay layer was dumped as a barrier for seepage water overlaid by a 3 m sandy layer consisting of Quaternary substrate from Pleistocene sediments. The surface of the site has been flattened and the area was fenced to prevent disturbances. Neither amelioration nor any reclamation measures were carried out afterwards. The site has been left for an unrestricted natural succession. In 2007 the Transregional Collaborative Research Centre (SFB/TRR 38) as a joint project between 3 Universities (BTU Cottbus, TU Munich and ETH Zurich) was launched and is funded by the German Research

  20. Laser and caries diagnosis: the state of the art and evaluation in vitro of the differences of the fluorescence between sound, carious and demineralized enamel; Laser e diagnostico de caries: estado da arte e avaliacao in vitro das diferencas de fluorescencia entre esmalte sadio, cariado e desmineralizado

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, Maria Angelica Lopes Chaves

    2001-07-01

    The aim of this study was to evaluate the methods for establishing dental caries diagnosis that make use of Laser light as source of illumination, establishing the 'state of the art'. Experimental observation of the differences among fluorescence of sound, demineralized and carious enamel by visible luminescent spectroscopy was also done. Six human teeth, extracted for clinical reasons were studied, and the results showed that the spectrum of carious enamel is different from the sound and demineralized ones. The differences are more evident relative to sond enamel and carious enamel, the same occurring between demineralized and carious enamel. The review of the literature aimed to make comparative considerations between QLF, LF and DELF; their effectiveness relative to traditional methods such as visual, visual with probe, radiography. It was verified that DELF was more sensitive, but could not discriminate between different degrees of mineral loss. QLF, compared to DIAGNOdent has the same sensitivity, but it is better for scientific purposes. The experimental part of the present study used on argon ion Laser to illuminated the teeth and signs of emission of fluorescence were captured by a PMT and then analyzed by a computer system with EG and G software. The results showed that the spectrum of carious enamel is different from the sound and demineralized. The differences are more evident in relation to sound and carious enamel, the same occurs between demineralized and carious enamel. (author)

  1. DEM interpolation based on artificial neural networks

    Science.gov (United States)

    Jiao, Limin; Liu, Yaolin

    2005-10-01

    This paper proposed a systemic resolution scheme of Digital Elevation model (DEM) interpolation based on Artificial Neural Networks (ANNs). In this paper, we employ BP network to fit terrain surface, and then detect and eliminate the samples with gross errors. This paper uses Self-organizing Feature Map (SOFM) to cluster elevation samples. The study area is divided into many more homogenous tiles after clustering. BP model is employed to interpolate DEM in each cluster. Because error samples are eliminated and clusters are built, interpolation result is better. The case study indicates that ANN interpolation scheme is feasible. It also shows that ANN can get a more accurate result by comparing ANN with polynomial and spline interpolation. ANN interpolation doesn't need to determine the interpolation function beforehand, so manmade influence is lessened. The ANN interpolation is more automatic and intelligent. At the end of the paper, we propose the idea of constructing ANN surface model. This model can be used in multi-scale DEM visualization, and DEM generalization, etc.

  2. Study on Electro-Polishing Process by Niobium-Plate Sample With Artificial Pits

    Energy Technology Data Exchange (ETDEWEB)

    T. Saeki, H. Hayano, S. Kato, M. Nishiwaki, M. Sawabe, W.A. Clemens, R.L. Geng, R. Manus, P.V. Tyagi

    2011-07-01

    The Electro-polishing (EP) process is the best candidate of final surface-treatment for the production of ILC cavities. Nevertheless, the development of defects on the inner-surface of the Superconducting RF cavity during EP process has not been studied by experimental method. We made artificial pits on the surface of a Nb-plate sample and observed the development of the pit-shapes after each step of 30um-EP process where 120um was removed by EP in total. This article describes the results of this EP-test of Nb-sample with artificial pits.

  3. Alteration of blue pigment in artificial iris in ocular prosthesis: effect of paint, drying method and artificial aging.

    Science.gov (United States)

    Goiato, Marcelo Coelho; Fernandes, Aline Úrsula Rocha; dos Santos, Daniela Micheline; Hadadd, Marcela Filié; Moreno, Amália; Pesqueira, Aldiéris Alves

    2011-02-01

    The artificial iris is the structure responsible for the dissimulation and aesthetics of ocular prosthesis. The objective of the present study was to evaluate the color stability of artificial iris of microwaveable polymerized ocular prosthesis, as a function of paint type, drying method and accelerated aging. A total of 40 discs of microwaveable polymerized acrylic resin were fabricated, and divided according to the blue paint type (n = 5): hydrosoluble acrylic, nitrocellulose automotive, hydrosoluble gouache and oil paints. Paints where dried either at natural or at infrared light bulb method. Each specimen was constituted of one disc in colorless acrylic resin and another colored with a basic sclera pigment. Painting was performed in one surface of one of the discs. The specimens were submitted to an artificial aging chamber under ultraviolet light, during 1008 h. A reflective spectrophotometer was used to evaluate color changes. Data were evaluated by 3-way repeated-measures ANOVA and the Tukey HSD test (α = 0.05). All paints suffered color alteration. The oil paint presented the highest color resistance to artificial aging regardless of drying method. PMID:21081281

  4. Artificial organic networks artificial intelligence based on carbon networks

    CERN Document Server

    Ponce-Espinosa, Hiram; Molina, Arturo

    2014-01-01

    This monograph describes the synthesis and use of biologically-inspired artificial hydrocarbon networks (AHNs) for approximation models associated with machine learning and a novel computational algorithm with which to exploit them. The reader is first introduced to various kinds of algorithms designed to deal with approximation problems and then, via some conventional ideas of organic chemistry, to the creation and characterization of artificial organic networks and AHNs in particular. The advantages of using organic networks are discussed with the rules to be followed to adapt the network to its objectives. Graph theory is used as the basis of the necessary formalism. Simulated and experimental examples of the use of fuzzy logic and genetic algorithms with organic neural networks are presented and a number of modeling problems suitable for treatment by AHNs are described: ·        approximation; ·        inference; ·        clustering; ·        control; ·        class...

  5. Comparison of light-induced and laser-induced fluorescence methods for the detection and quantification of enamel demineralization

    Science.gov (United States)

    Ando, Masatoshi; Analoui, Mostafa; Schemehorn, Bruce R.; Stookey, George K.

    1999-05-01

    The Quantitative Laser-Induced Fluorescence (QLF) technique has been sued for diagnosis of early caries in permanent teeth (PT). The objective of this study was to determine the caries quantification ability of QLF in deciduous teeth (DT). Sixty sound teeth, thirty DT and thirty PT, were used. All teeth were cleaned to remove debris and equally divided into three groups. Lesions were created in small windows (0.8x2.0 mm2) on buccal or labial surface for 48, 72, and 96 hr. Lesion images were made with a 488 nm argon laser (QLF I) and then with a 370 +/- 80 nm violet-blue light (QLF II). Both images were analyzed to determine the mean percent change in fluorescence radiance (ΔF). A center section from the lesions was taken for analysis with microradiography. The lesion depth and loss of mineral content were determined. The correlations between ΔF and lesion depth as well as ΔZ in DT were 0.76 and 0.84 with QLF I, 0.81 and 0.88 with QLF II, respectively. It can be concluded the ability of QLF to quantify white-spots in DT is better than in PT.

  6. Epistasis analysis using artificial intelligence.

    Science.gov (United States)

    Moore, Jason H; Hill, Doug P

    2015-01-01

    Here we introduce artificial intelligence (AI) methodology for detecting and characterizing epistasis in genetic association studies. The ultimate goal of our AI strategy is to analyze genome-wide genetics data as a human would using sources of expert knowledge as a guide. The methodology presented here is based on computational evolution, which is a type of genetic programming. The ability to generate interesting solutions while at the same time learning how to solve the problem at hand distinguishes computational evolution from other genetic programming approaches. We provide a general overview of this approach and then present a few examples of its application to real data.

  7. Advanced Artificial Intelligence Technology Testbed

    Science.gov (United States)

    Anken, Craig S.

    1993-01-01

    The Advanced Artificial Intelligence Technology Testbed (AAITT) is a laboratory testbed for the design, analysis, integration, evaluation, and exercising of large-scale, complex, software systems, composed of both knowledge-based and conventional components. The AAITT assists its users in the following ways: configuring various problem-solving application suites; observing and measuring the behavior of these applications and the interactions between their constituent modules; gathering and analyzing statistics about the occurrence of key events; and flexibly and quickly altering the interaction of modules within the applications for further study.

  8. Artificial intelligence methods for diagnostic

    International Nuclear Information System (INIS)

    To assist in diagnosis of its nuclear power plants, the Research and Development Division of Electricite de France has been developing skills in Artificial Intelligence for about a decade. Different diagnostic expert systems have been designed. Among them, SILEX for control rods cabinet troubleshooting, DIVA for turbine generator diagnosis, DIAPO for reactor coolant pump diagnosis. This know how in expert knowledge modeling and acquisition is direct result of experience gained during developments and of a more general reflection on knowledge based system development. We have been able to reuse this results for other developments such as a guide for auxiliary rotating machines diagnosis. (authors)

  9. Cybersecurity in Artificial Pancreas Experiments.

    Science.gov (United States)

    O'Keeffe, Derek T; Maraka, Spyridoula; Basu, Ananda; Keith-Hynes, Patrick; Kudva, Yogish C

    2015-09-01

    Medical devices have transformed modern health care, and ongoing experimental medical technology trials (such as the artificial pancreas) have the potential to significantly improve the treatment of several chronic conditions, including diabetes mellitus. However, we suggest that, to date, the essential concept of cybersecurity has not been adequately addressed in this field. This article discusses several key issues of cybersecurity in medical devices and proposes some solutions. In addition, it outlines the current requirements and efforts of regulatory agencies to increase awareness of this topic and to improve cybersecurity. PMID:25923544

  10. Improving designer productivity. [artificial intelligence

    Science.gov (United States)

    Hill, Gary C.

    1992-01-01

    Designer and design team productivity improves with skill, experience, and the tools available. The design process involves numerous trials and errors, analyses, refinements, and addition of details. Computerized tools have greatly speeded the analysis, and now new theories and methods, emerging under the label Artificial Intelligence (AI), are being used to automate skill and experience. These tools improve designer productivity by capturing experience, emulating recognized skillful designers, and making the essence of complex programs easier to grasp. This paper outlines the aircraft design process in today's technology and business climate, presenting some of the challenges ahead and some of the promising AI methods for meeting these challenges.

  11. Logical Foundations Of Artificial Intelligence

    Directory of Open Access Journals (Sweden)

    Angel Garrido

    2010-04-01

    Full Text Available The procedures of searching solutions to problems, in Artificial Intelligence, can be brought about, in many occasions, without knowledge of the Domain, and in other situations, with knowledge of it. This last procedure is usually called Heuristic Search. In such methods the matrix techniques reveal themselves as essential. Their introduction can give us an easy and precise way in the search of solution. Our paper explains how the matrix theory appears and fruitfully participates in A I, with feasible applications to Game Theory.

  12. Artificial intelligence a beginner's guide

    CERN Document Server

    Whitby, Blay

    2012-01-01

    Tomorrow begins right here as we embark on an enthralling and jargon-free journey into the world of computers and the inner recesses of the human mind. Readers encounter everything from the nanotechnology used to make insect-like robots, to computers that perform surgery, in addition to discovering the biggest controversies to dog the field of AI. Blay Whitby is a Lecturer on Cognitive Science and Artificial Intelligence at the University of Sussex UK. He is the author of two books and numerous papers.

  13. Preparation and Properties of Mesoporous Bioactive Glass / Demineralized Bone Composite Scaffolds%介孔生物活性玻璃/脱钙骨复合支架的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    薛士壮; 朱海霖; 陈建勇; 冯新星; 常江

    2011-01-01

    The composite scaffolds (MBG/DB) were prepared successfully through immersing the mesoporous bioactive glass powders into the demineralized bones. The bovine cancellous bone, demineralized bone, composite scaffold were investigated and characterized by FTIR, SEM, XRD and universal electromechanical testing machine. The results show that the compressive strength of the demineralized bones is about (1.10+0.31)Mpa, the porosity is about 71% and the pore size is in the range from 200 to 600μm. However, the porosity and the compressive strength of the composite scaffolds are decreased to 40% and increase markedly to (8.49 + 2.14)Mpa, respectively. Meanwhile, the composite scaffolds show good bioactivity in vitro.%将介孔生物活性玻璃(MBG)与脱钙骨(DB)复合,利用浸渍法制备出MBG/DB复合支架材料.采用红外光谱(FTIR),扫描电镜(SEM),X射线衍射(XRD),电子万能材料试验机等方法对牛松质骨(CB)、DB、MBG/DB复合支架进行表征.结果表明,CB经浸酸处理后制备的DB,孔径大小在200-600μm范围内,孔隙率约为71%,抗压性能比CB明显降低(1.10±0.31)MPa,而采用浸渍法制备的复合支架,孔隙率降为40%左右,而压缩强度明显提高(8.49±2.14)MPa.体外生物活性测试表明:复合支架具有良好的生物活性.

  14. 酸碱脱灰对煤结构及其热解特性的影响%Influence of demineralization on structure and pyrolysis characteristics of coal with acid-alkali method

    Institute of Scientific and Technical Information of China (English)

    肖劲; 李发闯; 邓松云; 仲奇凡; 赖延清; 李劼

    2016-01-01

    The ultra-clean coal was prepared by acid-alkali method, the influence of the demineralization on the structure and pyrolysis characteristics of coal were investigated comprehensively based on XRD, Raman spectroscopy, FTIR and TG/DTG tenologies. The results show that good effect of demineralization is achieved by acid-alkali method, and that the ash content of coal samples is reduced to below 0.5%. The molecular structure of the treated coal is destroyed and disordered structure is increased. The contents of hydroxyl and aliphatic functional groups (methyl, methylene) decrease in the ultra-clean coal, the Si—O—Si and Si—O groups disappear, but the number of oxygen functional groups such as phenol and ether increase significantly. Furthermore, demineralization has greater effect on the molecular structure of the coal with lower metamorphic degree. The barrier of mass and heat transfer is reduced by demineralization, thus the initial decomposition temperature (ts) and the maximum mass loss temperature (tmax) move to low temperature area, and the reaction is promoted during pyrolysis.%通过酸碱脱灰制备超纯煤,运用X线衍射(XRD)、拉曼光谱(Raman)、红外光谱(FTIR)和热重(TG/DTG)等分析技术研究酸碱脱灰对煤结构和热解特性的影响。研究结果表明:酸碱脱灰达到很好的脱灰效果,煤样灰分质量分数降低到0.5%以下;脱灰处理破坏煤中碳微晶结构,使煤中分子结构有序性减弱;脱灰煤中羟基和甲基、亚甲基脂肪烃类官能团含量减少,Si—O—Si和Si—O基团消失,酚、醚类含氧官能团含量显著增加;脱灰对低阶煤的分子结构影响较大;在热解过程中,脱灰煤的初始分解温度(ts)和最大质量损失温度(tmax)均向低温区推移;灰分脱除降低传质传热的势垒,有助于促进热解反应。

  15. Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

    Science.gov (United States)

    Yasuhiro, Matsuda; Katsushi, Okuyama; Hiroko, Yamamoto; Hisanori, Komatsu; Masashi, Koka; Takahiro, Sato; Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano

    2015-04-01

    To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials ["MS coats F" (MSF)] and fluoride-free sealing materials ("hybrid coats 2" [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8-4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

  16. ARTIFICIAL LIVING SYSTEM AND ITS COMPLEXITY

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yongguang

    2001-01-01

    In this paper the author shows some artificial living systems, whose basic life characteristics are explored, especially the differentiation in evolution from single cellular to multi-cellular organism. In addition, the author discusses diversity and evolvability also.The author gives a modified entropy function to measure the diversity. Finally, the author drops an open problem about the structure of "gene" of artificial living systems, so that we can measure the evolutionary order between the artificial living systems.

  17. Of Artificial Intelligence and Legal Reasoning

    OpenAIRE

    Sunstein, Cass Robert

    2014-01-01

    Can computers, or artificial intelligence, reason by analogy? This essay urges that they cannot, because they are unable to engage in the crucial task of identifying the normative principle that links or separates cases. Current claims, about the ability of artificial intelligence to reason analogically, rest on an inadequate picture of what legal reasoning actually is. For the most part, artificial intelligence now operates as a kind of advanced version of LEXIS, offering research assistance...

  18. Artificial neural networks in neurosurgery.

    Science.gov (United States)

    Azimi, Parisa; Mohammadi, Hasan Reza; Benzel, Edward C; Shahzadi, Sohrab; Azhari, Shirzad; Montazeri, Ali

    2015-03-01

    Artificial neural networks (ANNs) effectively analyze non-linear data sets. The aimed was A review of the relevant published articles that focused on the application of ANNs as a tool for assisting clinical decision-making in neurosurgery. A literature review of all full publications in English biomedical journals (1993-2013) was undertaken. The strategy included a combination of key words 'artificial neural networks', 'prognostic', 'brain', 'tumor tracking', 'head', 'tumor', 'spine', 'classification' and 'back pain' in the title and abstract of the manuscripts using the PubMed search engine. The major findings are summarized, with a focus on the application of ANNs for diagnostic and prognostic purposes. Finally, the future of ANNs in neurosurgery is explored. A total of 1093 citations were identified and screened. In all, 57 citations were found to be relevant. Of these, 50 articles were eligible for inclusion in this review. The synthesis of the data showed several applications of ANN in neurosurgery, including: (1) diagnosis and assessment of disease progression in low back pain, brain tumours and primary epilepsy; (2) enhancing clinically relevant information extraction from radiographic images, intracranial pressure processing, low back pain and real-time tumour tracking; (3) outcome prediction in epilepsy, brain metastases, lumbar spinal stenosis, lumbar disc herniation, childhood hydrocephalus, trauma mortality, and the occurrence of symptomatic cerebral vasospasm in patients with aneurysmal subarachnoid haemorrhage; (4) the use in the biomechanical assessments of spinal disease. ANNs can be effectively employed for diagnosis, prognosis and outcome prediction in neurosurgery.

  19. Artificial Compressibility with Entropic Damping

    Science.gov (United States)

    Clausen, Jonathan; Roberts, Scott

    2012-11-01

    Artificial Compressibility (AC) methods relax the strict incompressibility constraint associated with the incompressible Navier-Stokes equations. Instead, they rely on an artificial equation of state relating pressure and density fluctuations through a numerical Mach number. Such methods are not new: the first AC methods date back to Chorin (1967). More recent applications can be found in the lattice-Boltzmann method, which is a kinetic/mesoscopic method that converges to an AC form of the Navier-Stokes equations. With computing hardware trending towards massively parallel architectures in order to achieve high computational throughput, AC style methods have become attractive due to their local information propagation and concomitant parallelizable algorithms. In this work, we examine a damped form of AC in the context of finite-difference and finite-element methods, with a focus on achieving time-accurate simulations. Also, we comment on the scalability of the various algorithms. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  20. Artificial tissues in perfusion culture.

    Science.gov (United States)

    Sittinger, M; Schultz, O; Keyszer, G; Minuth, W W; Burmester, G R

    1997-01-01

    In the stagnant environment of traditional culture dishes it is difficult to generate long term experiments or artificial tissues from human cells. For this reason a perfusion culture system with a stable supply of nutrients was developed. Human chondrocytes were seeded three-dimensionally in resorbable polymer fleeces. The cell-polymer tissues were then mounted in newly developed containers (W.W. Minuth et al, Biotechniques, 1996) and continuously perfused by fresh medium for 40 days. Samples from the effluate were analyzed daily, and the pH of the medium and glucose concentration remained stable during this period. The lactid acid concentration increased from 0.17 mg/ml to 0.35 mg/ml, which was influenced by the degradation of the resorbable polymer fibers used as three dimensional support material for the cells. This perfusion system proved to be reliable especially in long term cultures. Any components in the culture medium of the cells could be monitored without disturbances as caused by manual medium replacement. These results suggest the described perfusion culture system to be a valuable and convenient tool for many applications in tissue engineering, especially in the generation of artificial connective tissue.