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Rare Case Report on Nevus of Ota
Chandak, Rakhi,Degwekar, Shirish,Chandak, Manoj,Bhowte, Rahul,Rawlani, Shivlal Korean Academy of Dental Science 2010 Journal of korean dental science Vol.3 No.1
Nevus of Ota is a hamartoma of dermal melanocytes. Clinically, Nevus of Ota is manifested as blue or gray patch on the face; such condition is congenital or acquired and is within the distribution of branches of the trigeminal nerve. The nevus can be unilateral or bilateral. In addition to skin, it may involve ocular and oral mucosal surfaces. The case of an 18-year old female with unilateral bluish black macule on the right side of the face since birth is presented. She also had a bluish patch on the right shoulder at birth, which disappeared when she turned 10 years. The pathogenesis of Nevus is unknown, and effective treatment has been realized with pigment-specific lasers.
Shear lag prediction in symmetrical laminated composite box beams using artificial neural network
Chandak, Rajeev,Upadhyay, Akhil,Bhargava, Pradeep Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.1
Presence of high degree of orthotropy enhances shear lag phenomenon in laminated composite box-beams and it persists till failure. In this paper three key parameters governing shear lag behavior of laminated composite box beams are identified and defined by simple expressions. Uniqueness of the identified key parameters is proved with the help of finite element method (FEM) based studies. In addition to this, for the sake of generalization of prediction of shear lag effect in symmetrical laminated composite box beams a feed forward back propagation neural network (BPNN) model is developed. The network is trained and tested using the data base generated by extensive FEM studies carried out for various b/D, b/tF, tF/tW and laminate configurations. An optimum network architecture has been established which can effectively learn the pattern. Computational efficiency of the developed ANN makes it suitable for use in optimum design of laminated composite box-beams.
Shear lag prediction in symmetrical laminated composite box beams using artificial neural network
Rajeev Chandak,Akhil Upadhyay,Pradeep Bh 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.1
Presence of high degree of orthotropy enhances shear lag phenomenon in laminated composite box-beams and it persists till failure. In this paper three key parameters governing shear lag behavior of laminated composite box beams are identified and defined by simple expressions. Uniqueness of the identified key parameters is proved with the help of finite element method (FEM) based studies. In addition to this, for the sake of generalization of prediction of shear lag effect in symmetrical laminated composite box beams a feed forward back propagation neural network (BPNN) model is developed. The network is trained and tested using the data base generated by extensive FEM studies carried out for various b/D, b/tF, tF/tW and laminate configurations. An optimum network architecture has been established which can effectively learn the pattern. Computational efficiency of the developed ANN makes it suitable for use in optimum design of laminated composite box-beams.
Lokade, Joyti,Rawlani, Shivlal,Baheti, Rakhi (Chandak),Roy, Shelly,Chandak, Manoj,Lohe, Vidya Korean Academy of Dental Science 2011 Journal of korean dental science Vol.4 No.1
Purpose: Exact knowledge of the location and dimension of the pulp chamber help to maintain the pulp healthy during operative procedure and also reduces the risk of perforation of pulp chamber during root canal treatment. This in-vivo study was carried out to measure critical morphology of pulp chamber of mandibular molar using intra-oral periapical radiograph. Materials and Methods: Mandibular molar teeth of 56 patients were evaluated. The mandibular molar teeth whose pulp chamber was not violated by caries, restoration, fracture crown and those having closed apex were included in the study. The intraoral periapical radiographs were taken with paralleling angle technique using radio-opaque grid with 1 mm space. This grid was placed directly on the film. Results: In 94% of the mandibular first molars specimens the pulp chamber ceiling was at the level of the cemento-enamel junction. The measurements showing the lowest percentage variance were buccal cusp to furcation (approximately 11%) and buccal cusp to pulp chamber ceiling (approximately 15%). The distance from the cusp tip to pulp chamber ceiling height was approximately 6.0 mm, the distance from the pulpal floor to the furcation was approximately 3.0 mm, and the average height of a pulp chamber was 1.5 to 2.0 mm. Conclusion: The exact knowledge of distances of pulp chamber from various anatomical landmarks helps in proper assessment of root canals and ultimately avoids the failure of root canal treatment.
Effect of Chelating Agents and Irrigants on Mineral Content of Root Canal Dentin: An In Vitro Study
Keyur Pankaj Chande,Narendra U Manwar,Manoj G Chandak,Jyoti Lokade,Sneha R Chandak 대한예방치과학회 2014 International Journal of Clinical Preventive Denti Vol.10 No.3
Objective: To evaluate and compare ex vivo the decalcifying effect of 17% ethylenediaminetetraacetic acid (EDTA), 15% citric acid, 37% phosphoric acid and 5.25% sodium hypochlorite on root canal dentin. Methods: Two 2-mm-thick slices were cut from the coronal third of the root of 24 human incisors. Each slice was sectioned into two equal parts. Specimens were assigned to one of four groups (n=24) for immersion in 20 ml of either 17% EDTA, or 15% citric acid, 37% phosphoric acid or 5.25% NaOCl, for three time periods (5, 10, and 15 minutes). The concentration of Ca2+ extracted from the dentine was measured by mass spectrophometry.The amount of calcium extracted was analysed using the Kruskal-Wallis test for global comparisons and the Mann-Whitney U-test for pairwise comparisons. Results: In the three time periods, 17% EDTA and 15% citric acid extracted the largest amount of calcium, with no significant differences between them. The 5.25% NaOCl solution extracted significant amounts of calcium, whereas 17% EDTA extracted 9.3 mg of the calcium in the first 5 min, and 15% citric acid and 37% phosphoric acid had a similar pattern of calcium removal (2.06 mg and 1.82 mg in first 5 minutes, respectively). Conclusion: Solutions of 15% EDTA, 15% citric acid and 5% phosphoric acid decalcify root dentine, with most calcium extracted during the first 5 minutes of action. The efficacy of 15% citric acid and 17% EDTA solutions was significantly greater than that of 37% phosphoric acid solution at each time period (5, 10 and 15 minutes).
Hemraj R. Kumavat,Narayan R. Chandak 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.5
It is a known fact that the concrete strength is not only affected by the ingredients present in it, but also by the other factors like types of cement used, compaction deficiency, curing condition, elevated temperature, and different w/c ratios. The influence on the rebound hammer has been illustrated in this paper concerning the hardness of the concrete specimens. The effect of cement types, compacting deficiency, w/c ratio, curing condition, and elevated temperature on concrete compressive strength and rebound hardness has been considered for the analysis. From an experimental study, it is found that the reduction of the compressive strength of concrete is between 6 to 41 percent due to insufficient compaction alone when tested using a destructive method. However, the rebound hammer results revealed that there is no reduction in the rebound index. The rebound hardness test cannot predict the compressive strength due to inadequate curing. It is also reported that the rebound index is significantly reduced, with the destructive strength of the concrete specimens. The study revealed that in the case of M30 and M40 grades of concrete, the percentage reduction of the average rebound index is almost higher in all the cases than the average compressive strength at a temperature ranging from 200°C to 800°C. The strength (rebound hardness) measured is either under or overestimated if no attention has been given to different influencing factors. Thus, a reliable and accurate evaluation of strength cannot be guarantee.
Jyoti Lokade,Sattyam Wankhade,Shelly Roy,Monaj Chandak 대한예방치과학회 2012 International Journal of Clinical Preventive Denti Vol.8 No.3
Objective: This in vitro study compare and evaluate Fracture Resistance of roots filled with gutta percha-AH Plus sealer and Resilon Epiphany with cold lateral and warm vertical compaction techniques. Interface of dentin, sealer and core material of each group were also evaluated under scanning electron microscope. Methods: 125 single-canal extracted mandibular first premolars were divided into five groups: lateral and vertical compaction with gutta-percha/AH Plus sealer, lateral and vertical compaction with Resilon Epiphany, and a control group with no filling material. The samples were stored in 100 percent humidity for two weeks, mounted in acrylic resin and loaded to failure under Instron testing machine. One sample from each group was longitudinally sectioned, placed in dessicator, sputter coated with gold palladium and evaluated by using scanning electron microscope to check the interface of dentin, sealer and core filling material. Results: Resilon epiphany groups displayed higher mean fracture loads and the gutta-percha groups lower mean fracture load values than the control unfilled group. There is no gap seen between Resilon Epiphany & dentin in lower manification (500×) & gap seen between gutta percha, sealer & dentin interface. There was one microgap seen at 2,000× power SEM between the Resilon filling & dentin at middle 1/3rd. There was no gap at 2,000× power SEM between Resilon, Epiphany and dentin at coronal and apical third. Conclusion: Filling the root canals with Resilon/Epiphany increases the in vitro resistance to fracture of roots of extracted teeth with single canal.