87,527 research outputs found
The role of hydrophilic interactions in determining preferential configurations in aqueous solution: alkan-1-ols, alkan-1,2-diols, alkan-α,ω-diols, and α-aminoacids interacting with glycine and its oligomers at 298.15 K
No full textEnthalpies of dilution of ternary aqueous solutions containing glycine, diglycine or triglycine and alkan-1-ols, alkan-1,2-diols, alkan-α,ω-diols, and α-aminoacids have been determined by microcalorimetry at 298.15 K. Pairwise cross interaction coefficients of the virial expansion of the excess enthalpies were evaluated. The values of these coefficients are positive, depending in a very complex manner on the number and position of the hydroxyl groups. The behaviour of these systems seems to be determined by a balance between favourable hydrophilic-hydrophilic and repulsive hydrophilic-hydrophobic interactions. The chaotropic agents employed play a major role: they are more complex than other purely hydrophilic substances, such as urea or biuret, because of the presence of hydrophobic domains on their molecules. © 1994
Evaluation of the Effect of Different Remineralizing Agents and Ozone Application on Artificial Carises
No full textThis study aimed to assess the combined and individual effects of different remineralization agents
and ozone application on initial caries. Seventy-two premolar teeth were collected. Three different
toothpastes (Ipana, ROCS, and Gumgumix) were utilized. The samples were divided into eight
groups (n = 8) for experimentation (Distilled water, Ipana+Ozone, Gumgumix+Ozone, ROCS
+Ozone, Ipana, Gumgumix, ROCS, Ozone). Microhardness measurements were conducted initially.
All samples were then immersed in a demineralization solution for 72 hours to induce initial caries.
Then, microhardness measurements were repeated, and pH cycles were carried out for one-week.
Finally, microhardness measurements and SEM-EDS analyses were performed. Ipana+Ozone exhibited
the highest microhardness value, which was statistically significant compared to other groups
except ROCS+Ozone (p < 0.05). Distilled water, Gumgumix+Ozone, and Gumgumix displayed the
lowest microhardness values. Ozone application with remineralization agents led to higher precipitation
of Ca ions. The demineralized group showed the lowest Ca, P, and F ions. While Ipana
+Ozone and ROCS+Ozone had the highest Ca ions, Gumgumix+Ozone had the highest P ions.
Within the study’s limitations, it can be concluded that ozone gas positively impacts the remineralization
process in initial caries lesions. Additionally, mineral-containing products demonstrated
a noteworthy capacity to reverse the demineralization process
Treatment alternatives for textile effluents containing dyes
No full textSon yıllarda su kirliliği kontrolü büyük önem kazanmıştır. Alıcı su kaynaklarına verilen boyar maddeler organik yük olarak bu kirliliğin küçük bir kısmını oluşturmaktadır; ancak alıcı ortamda çok düşük konsantrasyonlarda boyar madde bulunması bile estetik açıdan istenmeyen bir durumdur. Bu nedenle boyar madde içeren tekstil endüstrisi atıksularından renk giderim prosesleri ekolojik açıdan önem kazanmaktadır. Günümüzde boyar maddelerin giderimi büyük oranda fiziksel ve kimyasal yöntemlerle gerçekleştirilmektedir. Ancak bu yöntemlerin maliyeti oldukça yüksektir ve ortaya çıkan büyük miktardaki konsantre çamurun bertarafı problemlere neden olmaktadır. Bu nedenle büyük hacimli atıksulardaki boyar maddelerin etkili ve ekonomik bir şekilde giderilebilmesi için biyolojik sistemler gibi alternatif yöntemlere gereksinim vardır. Bu makalede, boyalı tekstil atıksuları için kimyasal, fiziksel ve biyolojik arıtım alternatifleri incelenmiştir.The control of water pollution has become of increasing importance in recent years. The discharge of dyes into the receiving waters constitutes only a small portion of water pollution. However the presence of very low concentrations of dyes in receiving waters is aesthetically undesirable. Therefore, treatment processes removing dyes from textile effluents have become important in order to conserve receiving waters. Nowadays, removal of dyes is carried out generally by physical and chemical methods. These methods are often very costly and accumulation of concentrated sludge creates disposal problems. For this reason, there is a need for alternative treatment methods, such as biological treatment which is efficient and economical in removing dyes from large volumes of effluents. This article discusses chemical, physical and biological treatment alternatives for textile wastewaters containing dyes
Efficiency of hydroxyl groups in promoting hydrophobic interactions. A calorimetric study of ternary aqueous solutions of alkan-1-ols and alkane-m,n-diols.
No full textHeats of dilution of ternary aqueous solutions containing alkan-1-ols and alkane-1,2-diols or alkane-alpha,omega -diols have been determined at 298.15 K by flow microcalorimetry. The pairwise interaction coefficients of the virial expansion of the excess enthalpies were evaluated and compared to those formerly obtained for binary aqueous solutions of alkan-m-ols or alkane-m,n-diols. The results were interpreted using the "preferential configuration" model, namely in terms of preferential interactions between hydrophilic domains and of repulsive interactions between hydrophobic and hydrophilic domains. Hydroxyl groups present a different efficiency in promoting hydrophobic interactions in dependence of their number and position in the interacting molecules. (C) 2000 Elsevier Science B.V. All rights reserved
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Microleakage Evaluation of Photopolymerization Efficiency in Different Layering Methods of New Generation Led Light Devices
No full textBackground/Aim: The aim of this study was to examine the
microleakage values after restoring the prepared Class II box cavities
using two different composite resins with three different layering methods
and polymerizing them with five different LED light devices. Material and
Methods: Class II box cavities were prepared in 150 extracted mandibular
molars. Nanoceramic composite resin (Ceram.x SphereTEC one universal
A2, Dentsply, Germany) and bulk fill composite resin (SDR flow+ A2,
Dentsply, Germany) were used for the restoration of the cavities. Teeth were
restored with three different layering methods (bulk fill, horizontal layering,
and centripetal buildup technique) and five different LED light devices
[(Smartlite Focus, Dentsply, USA), (Led.E, Woodpecker, China), (Valo
Cordless, Ultradent, USA), (Bluephase N, Ivoclar Vivadent, Liechtenstein),
(D-Light Pro (GC, USA)] and then subjected to microleakage analysis.
Kruskal Wallis and Mann Whitney U test were used for statistical analysis.
Th e data was evaluated under p<0.005 significant level. Results: Using
different layering methods did not affect microleakage scores statistically
(p=0.7683). Applying bulk-fill composite resin with 2 mm horizontal
layers or using the centripetal buildup technique did not show significant
differences in microleakage. Second- and third-generation light devices
demonstrated no statistical difference in microleakage (p=0.9075).
Conclusions: Using different layering methods and different curing units did
not make any difference in microleakage.
Keywords: Composite Resins; Curing Lights, Dental; Dental Leakage; Dental Restorations,
Permanent
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Bitkisel diş macunlarının başlangıç mine çürükleri üzerine remineralizasyon etkisinin değerlendirilmesi
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