Preparation of Biologically Derived Hydroxyapatite and its Dissolution

2007 ◽  
Vol 342-343 ◽  
pp. 657-660 ◽  
Author(s):  
Dong Seok Seo ◽  
Hwan Kim ◽  
Jong Kook Lee
Keyword(s):  
Tricalcium Phosphate ◽  
The Other ◽  
Distilled Water ◽  
Large Defect ◽  
Human Teeth ◽  
Liquid Environment ◽  
The Matrix ◽  
The Mean ◽  
Lattice Planes ◽  
Mean Time

Hydroxyapatite derived from human teeth was sintered at 1200°C for 2 h. Dissolving behavior of the biologically derived HA (BHA) in distilled water was investigated and compared with an artificial hydroxyapatite (HA) made of synthetic HA powder. All disks were immersed in 40 ml of pH 7.4 distilled water (buffered using 0.05 M Tris.) for 7 and 14 days at 37°C. All detectable peaks in the HA are identical only to HA lattice planes, whereas BHA consisted of a mixture of HA and β-tricalcium phosphate (TCP). In the case of the HA specimen, the surface dissolution was initiated at grain boundaries followed by generated many separated grains and large defect like cavities. On the other hand, biologically derived HA showed that definite grains considered as β-TCP was predominantly dissolved and the grains were separated from the matrix leaving pores. In the mean time, the rest region, mainly consisting of HA, did not show any evidence of dissolution. It seems that BHA is more stable than the artificial HA in liquid environment.

scholarly journals Effect of gingival retraction cord and retraction paste on gingival tissue in fixed prosthodontics impression

2014 ◽  
Vol 3 (2) ◽  
pp. 20-27
Author(s):  
Mohammad Shamsuzzaman ◽  
Sheikh Md Shahriar Quader ◽  
Shakila Fatema ◽  
Md Abdul Gofur ◽  
Khaleda Akter
Keyword(s):  
The Other ◽  
Gingival Tissue ◽  
Hemorrhage Control ◽  
Fixed Prosthodontics ◽  
Abutment Teeth ◽  
The Mean ◽  
Mean Time ◽  
Reduced Time

Background & Objectives: Of the various gingival retraction systems available in the market, a cordless paste system is fairly new entrant into this field. This system promises to provide an easier method to obtain optimum retraction with excellent hemorrhage control. The present study was designed to clinically evaluate the efficacy of paste retraction system and medicated retraction cords on the basis of relative easy of working, hemorrhage control and amount of vertical gingival retraction. Methods: 40 subjects were selected requiring full veneer restoration where more than one abutment teeth were to be prepared. After the preparation of the abutment teeth flexible scales were used to measure the sulcus depth before retraction and after retraction. Medicated retraction cord technique was used on one abutment tooth and on the other abutment tooth paste retraction system was employed. Subjectively easy of placement and hemorrhage scores was assessed. Results: The mean time taken for paste retraction technique was 45.13 seconds and for medicated retraction cord technique was 105.4 seconds. In all the subjects paste retraction technique was relatively easier as compared with medicated retraction cord technique. Mean hemorrhage scores using paste retraction technique was 0.05 and using medicated retraction cord technique it was 1.70. Mean vertical gingival retraction using paste retraction technique was .36mm and using medicated retraction cord technique was 0.54mm Conclusion: Within the limitations of this study, paste retraction system requires reduced time for application, is easier to place, and provides excellent hemorrhage control in comparison to medicated retraction cord. However, medicated retraction cord provides increased amount of vertical retraction as compared to paste retraction technique. DOI: http://dx.doi.org/10.3329/updcj.v3i2.17995 Update Dent. Coll. j: 2013; 3 (2): 20-27

Reliability Analysis of a System with Multiple-Stage Policy Considering Type I and II Errors

2019 ◽  
Vol 26 (06) ◽  
pp. 1950028
Author(s):  
Mitsuhiro Imaizumi ◽  
Mitsutaka Kimura
Keyword(s):  
Type I Error ◽  
The Other ◽  
Renewal Processes ◽  
Type I ◽  
Numerical Examples ◽  
Markov Renewal Processes ◽  
The Mean ◽  
Mean Time ◽  
Server System ◽  
Multiple Stages

This paper formulates a stochastic model for a system with illegal access. The server has the function of IDS, and illegal access is checked in multiple stages which consist of simple check and detailed check. In this model, we consider type I and II errors of simple check and a type I error of detailed check. There are two cases where IDS judges the occurrence of illegal access erroneously. One is when illegal access does not occur, and the other is when illegal access occurs. We apply the theory of Markov renewal processes to a system with illegal access, and derive the mean time and the expected checking number until a server system becomes faulty. Further, an optimal policy which minimizes the expected cost is discussed. Finally, numerical examples are given.

Eating and ruminating behaviour in cattle given forages differing in fibre content

1989 ◽  
Vol 48 (3) ◽  
pp. 503-511 ◽  
Author(s):  
M. N. McLeod ◽  
B. R. Smith
Keyword(s):  
Dry Matter ◽  
The Other ◽  
Fibre Content ◽  
Eating Rate ◽  
High Fibre ◽  
Acid Detergent Fibre ◽  
The Mean ◽  
Voluntary Intake ◽  
Mean Time ◽  
Forage Diets

ABSTRACTA study was made of the effect of fibre level in forages on eating and rumination behaviour. Eight forage diets were prepared from the leaf and stem fractions of two grasses and two legumes and were given at hourly intervals to four steers under steady-state conditions. Eating and rumination behaviour were measured automatically by recording changes in intra-oesophageal pressure.Mean voluntary intake of leaf was higher than that of the stem fractions (9·9 v. 5·6 kg/day; P < 0·001). This was associated with a shorter mean retention time in the rumen of the leaf than that of the stem fractions (21·4 v. 30·6 h; P < 0·001) and a lower concentration (g/100 g dry matter (DM)) of fibre (52-0 neutral-detergent fibre (NDF) and 30·5 acid-detergent fibre (ADF) v. 68·2 NDF and 45·3 ADF). Similar values (P > 0·05) between diets were found for both the water and DM contents of the rumen (60·1 kg, 7·8 kg). Voluntary intake was not related to either.No difference was found between forage diets in the mean time (132 min) and number (18·7) of periods spent eating each day (P > 0·05). Legume leaf fractions were eaten at a faster rate (g/min) than either the grass leaf or the stem fractions. Voluntary intake was related to the rate at which food was eaten (r = 0·89; P < 0·01) but no relationship was found with the time taken to eat food (r = –0·14; P>0·05). Eating rate was related to the level of both NDF (r = –0·91; P < 0·01) and ADF (r = –0·96; P < 0·001).Differences between diets were found in rumination times (mean 425 min; P < 001), the number of boluses regurgitated during each period (27·6; P < 0·05) and during each day (485; P < 0·001), and in the weight of boluses (455 g; P < 0·05). No differences (P > 0·05) were found between diets in the mean number of rumination periods each day (17·6), the mean time spent ruminating during each period (24·3 min), the mean rate at which boluses were regurgitated (53·2 s per bolus), the interval between boluses (5·1 s), and the DM in a bolus (27·5 g). Rumination time and the number of boluses regurgitated either per period or per day were not related to the fibre content of the diet (P > 0·05).The regurgitated boluses from leaf fractions were chewed less than the stem fractions (43·7 v. 54·7 chews per bolus). The regurgitated boluses of lucerne leaf were chewed at a faster rate (1·13 chews per s; P > 0·05) than regurgitated digesta of the other diets which were chewed at similar rates (0·97 chews per s; P > 0·05). The total number of rumination chews made each day by animals given lucerne leaf (12 300) was much lower (P < 0·001) than that by animals given the other fractions (25 300). The number of chews made on each bolus was related to fibre levels in the diets (NDF, r = 0·78, P < 0·05; ADF, r = 0·91, P < 0·01).It is concluded that the voluntary intake of high-fibre diets is not always restricted by rumen fill or rumination. The ease with which forage is eaten should be investigated as a factor influencing intake of fibrous forages.

Seroconversion of puppies to canine parvovirus and canine distemper virus: a comparison of two combination vaccines

2000 ◽  
Vol 36 (2) ◽  
pp. 137-142 ◽  
Author(s):  
MJ Coyne
Keyword(s):  
Canine Distemper Virus ◽  
Serum Antibody ◽  
Canine Parvovirus ◽  
The Other ◽  
Canine Distemper ◽  
Combination Vaccines ◽  
Antibody Titers ◽  
The Mean ◽  
To Receive ◽  
Mean Time

Sixty puppies were randomly assigned to receive one of two commercially available combination vaccines, and responses to the canine parvovirus and canine distemper virus components of the vaccines were determined by measuring serum antibody titers. The percentage of puppies that seroconverted to canine parvovirus was significantly higher and the mean time for seroconversion was significantly shorter for puppies that received one of the vaccines than for puppies that received the other vaccine. Percentages of puppies that seroconverted to canine distemper virus were not significantly different.

Studies on the sultana vine. II. The course of bud burst.

1955 ◽  
Vol 6 (5) ◽  
pp. 713 ◽  
Author(s):  
AJ Antcliff ◽  
WJ Webster
Keyword(s):  
The Other ◽  
Bud Burst ◽  
Four Seasons ◽  
Bud Position ◽  
The Mean ◽  
Mean Time

Sultana vines were examined during bud burst for four seasons, and the date on which each shoot arose was noted. The shoots were later classified as fruitful, barren, or defective. The vines were pruned uniformly in the first season, and two pruning treatments were compared in the other three seasons. In all cases the mean time of bursting a t each bud position was progressively later from the distal to the proximal end of the cane, the number of newly burst buds found at each examination was related to preceding temperatures, and the percentage of fruitful shoots among new shoots found at each examination decreased from the beginning to the end of bud burst. Accessory shoots arising as a result of the death of primary shoots or buds were very rarely fruitful. The results are considered in relation to the discrepancy sometimes found between the percentage of fruitful buds and the percentage of fruitful shoots.

Comparative Study for the Dissolution of Bone Ash-Derived and Artificial Hydroxyapatite

2012 ◽  
Vol 488-489 ◽  
pp. 592-596
Author(s):  
Jong Kook Lee ◽  
Heong Jun Kim ◽  
Woo Yang Jang
Keyword(s):  
Calcium Oxide ◽  
Tricalcium Phosphate ◽  
Immersion Time ◽  
High Stability ◽  
Raw Materials ◽  
The Other ◽  
Liquid Environment ◽  
Bone Ash ◽  
Naoh Solution ◽  
Moisture Protection

Hydroxyapatite (HA) ceramics were prepared from the bone ash which is mostly used as animal feeds or raw materials. Dissolving behaviors of the HA in buffered water were investigated and compared with commercial HA for further use as biomaterials. HA ceramics were prepared by soaking the bone ash in 0.1 M of NaOH solution at 80°C for 4 h. The ash was calcined at 800°C for 1 h to completely remove organics, and then sintered at 1200°C for 1 h under moisture protection. The bone ash derived-HA consists of mostly HA and small amounts of α-tricalcium phosphate, calcium oxide phosphate, magnesium oxide and calcium oxide. After polishing the HA ceramics, they were immersed in buffered water at 37°C for 3 and 7 days. We previously found that grain boundaries of synthetic HA were intensively dissolved in buffered water. On the other hand, the bone ash derived-HA shows high stability in liquid environment with immersion time compared with commercial HA.

scholarly journals IV. On practical methods for rapid signalling by the electric telegraph

1857 ◽  
Vol 8 ◽  
pp. 299-303 ◽  
Keyword(s):  
Royal Society ◽  
The Other ◽  
Short Article ◽  
Practical Applications ◽  
Actual Use ◽  
The Mean ◽  
Working Out ◽  
Mean Time

I am at present engaged in working out various practical applications of the formulæ communicated some time ago in a short article on the “Theory of the Electric Telegraph” (Proceedings, May 17, 1855), and I hope to be able very soon to lay the results in full before the Royal Society. In the mean time, as the project of an Atlantic Telegraph is at this moment exciting much interest, I shall explain shortly a telegraphic system to which, in the course of this investigation, I have been led, as likely to give nearly the same rapidity of utterance by a submarine one-wire cable of ordinary lateral dimensions between Ireland and Newfoundland, as is attained on short air or submarine lines by telegraphic systems in actual use. Every system of working the electric telegraph must comprehend (1) a plan of operating at one extremity, (2) a plan of observing at the other, and (3) a code of letter-signals. These three parts of the system which I propose will be explained in order,—I. for long submarine lines, and II. for air or short submarine lines.

scholarly journals KEPERCAYAAN MEREK DAN BRAND AFFECT SEBAGAI ANTESEDEN DARI LOYALITAS MEREK

Media Ekonomi ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 9
Author(s):  
Sri Rahayu ◽  
Mugi Harsono
Keyword(s):  
Competitive Advantage ◽  
Brand Loyalty ◽  
The Other ◽  
Brand Trust ◽  
Social Expression ◽  
The Mean ◽  
Marketing Costs ◽  
Brand Affect ◽  
Mean Time

The purpose of this paper is to explain the important role of brand and brand loyalty inmarketing activities. This paper also explains the antecedents of brand loyalty. The role of a branddoes not only actas a name, but also increasing the company's competitive advantage. The benefitsof a brand for consumers are, among many others, for emotional, self and social expression,attitudes, values and culture benefits. In the mean time, the role of brand loyalty in marketingis to contribute to the survival of the company, to increase new customer opportunities as well asto reduce marketing costs. To improve a brand loyalty, a companyshould increase its brand trustin advance as it plays an important role in improving brand loyalty. A cpmpany brand trust hastwo dimensions of intention and reliability. Brand affect, on the other hand, is an important forimproving a brand loyalty. Therefore,a company’sbrand trust and brand affect should be improvedfor the brand loyalty to improve as well.Key words : Brand trust, Brand Affect, Brand Loyalty

scholarly journals MEDIA MASSA DALAM BINGKAI KEKUASAAN (Analisis Wacana Berita Munas Golkar di Metrotv dan tvOne)

2016 ◽  
Vol 1 (2) ◽  
pp. 141
Author(s):  
Anwari Anwari
Keyword(s):  
Discourse Analysis ◽  
The Other ◽  
Not Given ◽  
Equal Share ◽  
News Discourse ◽  
Black List ◽  
The Mean ◽  
Mean Time

There are two issues that are examined in this study (1) Do MetroTv and tvOne use a balanced or unbias perspective in telling reports on the 8th Golkar Assembly to the chairman of the Golkar candidates (2) Is there any discourse of domination in the news about the 8th Golkar Assembly. To tell these issues in depth, this study uses discourse analysis of Teun A Van Dijk models which are useful to know and understand whether MetroTV and TVOne use impartial perspective in telling the 8th Golkar Assembly for the candidates and that there is Golkar chairman domination in news discourse of the 8th Golkar Assembly. This study found that tvOne news was dominated by a candidate of Golkar chairman, Bakrie, while the other candidates are not given an equal share in announcing the nomination of Golkar chairman. In the mean time, MetroTV announcing the nomination of Golkar chairman candidates to the election of Golkar chairman for 2009-2014 period, and MetroTV also explained clearly to the community only, the other candidates are not given an equal share in announcing the chairman of Golkar. Nomination black list was there in the news of MetroTV which was done to marginalize other groups.

Phase Interactions in Monoclinic Zirconia Reinforced Hydroxylapatite Bioceramics

Volume 1 ◽  
2004 ◽  
Author(s):  
Celaletdin Ergun ◽  
Zafer Evis ◽  
Robert H. Doremus
Keyword(s):  
Thermal Analysis ◽  
Tricalcium Phosphate ◽  
Hot Pressing ◽  
Monoclinic Zirconia ◽  
Pure Zirconia ◽  
Different Temperatures ◽  
The Mean ◽  
Zirconia Phase ◽  
Mean Time

Hydroxylapatite composites with pure zirconia were prepared with pressureless air sintering and hot pressing for 1 hour at different temperatures between 900°C and 1300°C. The interaction between the phases was monitored with XRD and thermal analysis. At sintering temperatures higher than 1000°C, an apparent Ca diffusion occurred from hydroxylapatite to pure zirconia phase and changed its structure from monoclinic to tetragonal/cubic. In the mean time, hydroxylapatite decomposed and formed tricalcium phosphate. Also, a reaction was occurred at 1220°C between hydroxylapatite and zirconia phase forming CaZrO3. The existence of air in the processing environment increased the reactivity between hydroxylapatite and zirconia.

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