527 research outputs found
COMMUNICATION SKILL LEVELS IN TURKISH PROSPECTIVE TEACHERS
No full textThe author of this study tested whether Turkish prospective teachers' levels of communication skill differed significantly according to submissive acts, self-images drawn from social comparisons, and several other personal variables. A total of 274 persons participated in this study. The Communication Skills Assessment Scale (Korkut, 1996), The Submissive Acts Scale (Gilbert & Allan, Turkish version Sahin & Sabin, 1992), The Social Comparison Scale (Gilbert & Allan, Turkish version Sahin & Sabin, 1992) and a personal information form developed by the author were used for data collection. Results showed that individuals with a positive self-image, those who perceived themselves as popular and assertive, those coming from a higher income status, and individuals with perceived democratic parental styles reported higher levels of communication skills. No significant differences were found in prospective teacher's communication skills according to submissive acts.https://www.ingentaconnect.com/content/sbp/sbp/2008/00000036/00000009/art00013;jsessionid=1lwuannye493u.x-ic-live-01</p
The effect of different cleaning agents and resin cement materials on the bond strength of contaminated zirconia
No full textThe purpose of this study was to examine the effect of different cleaning methods and resin cements on the shear bond strength (SBS) of contaminated zirconia. A total of 92 disc-shaped zirconia specimens were contaminated with different procedures. Then, the specimens were grouped according to cleaning methods and resin cements: no cleaning + Variolink Esthetic DC (CNV), no cleaning + Panavia V5 (CNP), sandblasted + Variolink Esthetic DC (SBV), sandblasted + Panavia V5 (SBP), Ivoclean + Variolink Esthetic DC (ICV), Ivoclean + Panavia V5 (ICP), Katana Cleaner + Variolink Esthetic DC (KCV), and Katana Cleaner + Panavia V5 (KCP). Following an aging protocol in a 37 degrees C for 1 week, SBS analysis was performed with a universal test machine. For the surface topography and elemental analysis, scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS) were used. Significance was evaluated as p .05 and p .01. The highest SBS results were found in the SBP group, showing a statistically significant difference from all other groups (p .05). For the same cleaning method, Panavia V5 showed statistically significantly higher SBS values than Variolink Esthetic DC (p .01), except the CNP-CNV (p = .880) and KCP-KCV (p = .082) groups. The most detected surface elements by EDS were Zr, O, C, and N, respectively. The contaminated zirconia surfaces must be cleaned for successful adhesion. The use of phosphate-containing adhesives in combination with sandblasting will increase the adhesion strength, and universal cleaning agents can be a good alternative to sandblasting
Porselen laminate veneerler hakkındaki YouTube videolarının değerlendirilmesi
No full textAmaç: Bu çalışmanın amacı, estetik dental uygulamalardan biri olan porselen laminate veneer uygulamaları hakkındaki YouTube videolarının içeriğini değerlendirmektir.Gereç ve Yöntem: ‘Porselen laminate veneer’ anahtar sözcükleri kullanılarak YouTube’da sistematik bir arama yapıldı. Videolar yükleyiciye göre sınıflandırılıp, bilgi içerikleri değerlendirildi. Video bilgileri-kalite indeksi aracılığıyla video kalitesi hesaplandı. Ayrıca videoların etkileşim ve görüntülenme oranları da analiz edildi. Elde edilen veriler, istatistiksel olarak incelendi ve anlamlılık p0.01 ve p0.05 düzeylerinde değerlendirildi.Bulgular: Çalışma kapsamında taranan ilk 120 video içerisinden 70 video çalışmaya dahil edildi. Video yükleyicilerine göre dağılımlar değerlendirildiğinde, en fazla videonun TV kanalları (n=17, %25.3) tarafından yüklendiği görüldü. Video yükleyicileri değişmeksizin, tüm videoların bilgi içeriğinin yetersiz olduğu tespit edildi. Protetik diş tedavisi uzmanları tarafından yüklenen videoların daha fazla izlendiği ve etkileşim oranlarının istatistiksel olarak daha yüksek olduğu (p0.05), ancak bu videoların bilgi içeriği açısından diğer yükleyicilere ait videolardan yetersiz olduğu tespit edildi.Sonuç: Porselen laminate veneerler ile ilgili YouTube videolarının bilgi içerikleri yetersiz bulundu. En çok görüntülenen YouTube videoları, protetik diş tedavisi uzmanlarına ait olsa da bu videoların içeriklerinin bilgi akışı ve video kalitesi gibi parametreler açısından diğer yükleyicilere göre daha yetersiz olduğu tespit edildi
Grayanotoxin-III Detection and Antioxidant Activity of Mad Honey
No full textSahin, Huseyin/0000-0002-6018-1494WOS: 000359160500006Mad honey is a complex mixture of numerous chemicals produced by honeybees from Rhododendron flowers. Consumption of mad honey leads to diarrhea, perspiration, dizziness, changes in consciousness, syncope, diplopia, as well as blurred vision, hypotension, and bradycardia due to the presence of grayanotoxins (GTXs). Therefore, it is important to detect the level grayanotoxins in mad honey. Besides its toxicity, mad honey also has antioxidant activity. This study was designed to determine the level of grayanotoxin-III toxin and antioxidant activity of ten different mad honey samples collected from the Black Sea region of Turkey. Liquid chromatography-tandem mass spectrometry was used for the quantitation of grayanotoxin-III. Antioxidant activity was evaluated using total phenolic contents, total ferric reducing antioxidant power, scavenging of 2,2-diphenyl-1-picrylhydrazyl and 3-(2-pyridyl)-5, 6-diphenyl-1,2,4-triazine-4',4''-disulfonic acid radicals. Quantities of grayanotoxin-III levels ranged from 68.754 to 0.701 mu g grayanotoxin-III/g honey. Mad honey MH7 from Artvin/Hopa had the highest grayanotoxin-III level. Although there were varying levels of grayanotoxin-III, mad honey samples were outstanding in terms of antioxidant activity. MH3 had the highest antioxidant potential. Although toxicity effect comprises, a metered dose of mad honey might also be explored as a potential source in clinical trials due to high bioactivity levels.TAGEMGida Tarim Ve Hayvancilik Bakanligi [AR-GE/15]; Tubitak BidebTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK)The study was supported by TAGEM AR-GE/15, and author Huseyin Sahin was supported by a grant from the research fund of Tubitak Bideb for his Ph.D. research
Study on Use of MSWI Fly Ash with Mainstream Supplementary Cementitious Materials
No full textThe management of municipal solid waste incineration fly ash (MSWI FA) has become a critical issue as its generation increases rapidly along with the global population growth. In this study, MSWI FA was treated via water-washing, and then the untreated and water-treated MSWI FAs (RFA and WFA) were blended with mainstream supplementary cementitious materials (SCMs), including ground granulated blast-furnace slag (GS), silica fume (SF), and limestone powder (LS). The MSWI FASCMblends were used as a cement replacement in a mortar. The content of MSWI FAs was set at 10% (by weight of binder) for all mortar mixtures. The content of GS and LS was also set at 10%, while the SF content was 2.5%. Flowability, setting time, isothermal calorimetry, compressive strength, and free-drying shrinkage tests were performed. The results showed that mortars containing raw (untreated) fly ash (RFA) had reduced strength, whereas mortars containing water-treated fly ash (WFA) displayed comparable or even higher strength than the control mortar (made with 100% cement) after 28 days. While mortars containing RFA showed increased drying shrinkage, mortars containing WFA exhibited diminutive or no increase in drying shrinkage when compared to the control mortar. Based on the test results, the mixture with a cement:WFA:GS ratio of 80:10:10 was the optimal binder for concrete applications.This symposium paper published as Wi, Kwangwoo, Oguzhan Sahin, Kejin Wang, and Yunsu Lee. "Study on Use of MSWI Fly Ash with Mainstream Supplementary Cementitious Materials." Special Publication 362 (2024): 871-886. doi: https://doi.org/10.14359/51742015.The work presented here is part of a project (AWD-024847) sponsored by the City of Ames, Iowa, and the Center for Industrial Research and Service, Iowa State University (ISU), USA. The authors sincerely acknowledge the sponsorship. The second author, Dr. Oguzhan Sahin, would thank the Scientific and Technological Research Council of Turkey (TUBITAK) for the support of his visit at ISU through the "2219-International Postdoctoral Research Fellowship Program for Turkish Citizens"
Deviation of Dental Implants Placed by Guided Implant Surgery in Bone Structures with Different Densities.
No full textPurpose: This study aimed to evaluate the deviations of implants with two different geometries placed with a bone-supported stereolithographic surgical template into the bone of Misch classification densities of D2, D3, and D4. Materials and Methods: Eight maxilla and eight mandible models were macrodesigned according to the jaw geometries. Bone densities of these models were created in parallel with the most frequently observed densities in the locations: D3 bone density in the anterior maxilla, D4 bone density in the posterior maxilla, D2 bone density in the anterior mandible, and D3 bone density in the posterior mandible. A bone-supported stereolithographic surgical template was prepared in accordance with the jaw models and planning and used to place 64 NobelParallel Conical Connection RP 4.3 × 13 mm and 64 NobelActive 4.3 × 13 mm implants on the models. Global deviation, lateral deviation, angular deviation, and depth deviation between planned and placed implants were calculated with Hypermesh. The Kruskal-Wallis test was used to analyze the differences between deviation data of the study groups, and the Mann-Whitney U test was used for pairwise comparisons of groups with significant differences. Significance was evaluated as P .05). When the data of all studies were evaluated, the deviation values for all maxillary and mandibular implants were examined regardless of bone and implant type; no statistical difference was found between the arches in terms of deviation type (P > .05). Conclusion: Regardless of the macrogeometry of the dental implants placed with the guide, no significant difference was observed between the deviation values of the different bone densities they were applied to
Evaluation of residual contamination on reused healing abutments
No full textObjectives The purpose of this study is to evaluate residual contamination of healing abutments sterilized by dealers of dental implant companies. Material and methods Healing abutments collected from dealers of different implant companies were randomly numbered, and they were examined for visible deformation and contamination on the abutment surface, packaging errors, and presence of a sterilization indicator. The healing abutments were stained with a dye solution for contamination detection and evaluated by dividing into different regions. The presence of residual contamination was examined through photographic images taken from the healing abutments and the data obtained were recorded. Pearson's chi-square analysis was used to evaluate the relation between implant brands and contamination status. Significance was evaluated as p Results Visible residual contamination was detected in approximately 31% of the healing abutments. After the staining procedure, in the visual assessment of the stained surfaces, residual contamination was found in at least one region of all healing abutments except one (n=176, 99.4%). The most intense staining was seen in the screw driver hole (n=172, 97.1%), body (n=113, 63.8%), occlusal (n=107, 60.4%), screw (n=79, 44.6%), and connector (n=72, 40.6%) regions, respectively. A significant relationship was found between the brands and the contamination status (p 0.05). Conclusion The reuse of healing abutments is not suitable, as it does not ensure optimum cleaning and sterilization, and it is not possible to eliminate contaminants completely
Quality of information in -Masseter botox- videos on YouTube: Is it a sufficient guide for potential patients?
No full textIntroduction: Recently, the usage of social media for information purposes by patients has gained popularity. Objectives: This study aims to evaluate the content of YouTube videos about botulinum toxin injections applied to the masseter muscle. Material and methods: A systematic search of YouTube videos was conducted using the key words "masseter Botox", and 102 videos were included in the study. The videos were classified according to type and uploader, and the information content was evaluated. Video information and quality index were used and viewing rates of the videos were also calculated. Results: Data obtained were analyzed statistically. Most of the videos were found to be information videos (79.4%), and most of them uploaded by beauty centers (34.3%). The information content of the educational and information videos was found to be statistically higher than the patient experience videos (p 0.01). When the viewing rates of the videos were examined, it was found that the patient experience videos were observed more, and the interaction rates were statistically higher (p 0.01). Conclusions: The information content of the masseter Botox-related YouTube videos was found to be insufficient. It is important to overcome this shortcoming with videos with high information content prepared by experts in related fields. © 2020 Termedia Publishing House Ltd.. All rights reserved
Limiting factors of the tensile strength of aramid fibers
No full textThe correlation between the evolution of crystallite orientation in aramid fibers during loading and their mechanical and failure behavior were investigated. Three types of as-spun aramid fibers and a heat-treated type were employed with initial distributions of crystallite orientations between 16.7º and 9.7º with respect to the fiber axis. These directly correlated with the initial moduli that were between 66 GPa and 119 GPa, with no correlation between the initial crystallite orientation distribution and the tensile strength values that ranged between 3.5 and 4.0 GPa. Cyclic loading of individual, 10 mm long, as-spun filaments increased their initial moduli, all converging to 100 GPa for all fiber types when cycled to 90% of their respective tensile strength values. This modulus value (100 GPa) corresponds to a stable crystallite orientation distribution of 11.6º. On the other hand, the initial unloading modulus of all fiber types when loaded to 90% of their tensile strength converged to ~165 GPa which approaches the theoretical modulus of 220 GPa for monopolymer aramids. This limit value of the unloading modulus also signifies the tightest crystalline domain orientation distribution of 6.6º with respect to the fiber axis. However, this orientation distribution is not retained upon unloading. On the other hand, as-fabricated, post-spun heat-treated fibers had a much higher initial modulus of 120 GPa, and an initial unloading modulus of 170 GPa after mechanical cycling to 90% of their tensile strength value, corresponding to 5.8º domain orientation distribution. In all aramid types, mechanical cycling increased the initial modulus by as much as 54% while leaving the tensile strength of each fiber type unaffected in the narrow range of the aforementioned initial values. Thus, the limiting orientation distribution of ~6º emerges as the controlling factor in tensile failure of this class of fibers. Tension tests conducted at different strain rates showed that the permanent orientation of crystalline domains at high strains/stresses scales inversely with the applied strain rate. Notably, at strain rates of 0.2-0.3 s -1 both as-spun and heat-treated fibers were linearly elastic until failure.
A hypothesis that the fiber tensile strength is controlled by preexisting defects was tested by examining the scaling of the tensile strength with the fiber gauge length for fibers with lengths in the range of 200 µm to 10 mm. Prior works that were limited to fiber gauge lengths longer than 2 mm, have been inconclusive due to large data scatter for short fibers. Controlled tests conducted in this dissertation research with dedicated test apparatuses for small scale experimentation, demonstrated a constant tensile strength for gauge lengths as short as 200 µm, thus, implying that failure does not obey weakest link statistics that are descriptive of critical flaw-induced failure initiation. Notably, in short gauge length fibers (200 µm) of all aramid types failure initiation occurred near the skincore interface, followed by extrusion of the fiber core from the skin. Thus, the microstructural differentiation between the fiber core and the skin presents a likely limiting factor in tensile strength of aramid fibers.
Finally, the shear strength of the fiber core was measured for the first time with novel experiments that were designed and implemented with the aid of surface micromachined Microelectromechanical Systems (MEMS) devices. Edge notches were milled out in individual fibers using a focused ion beam to generate a zone of uniform shear stress along the fiber, when the latter was subjected to uniaxial tension. The optimum specimen design and specimen geometry were guided by a finite element analysis to shape the notch tip such that the stress singularity is eliminated and a uniform shear dominant plane is achieved. These unique but also challenging experiments were carried out on aramid fibers with the lowest orientation of 16.7º resulting in average shear strength of 85±7.6 MPa.
In conclusion, this dissertation research established new experimental tools and methods to investigate the origin of failure initiation in aramid fibers manufactured under different conditions. A limiting orientation distribution angle was established for all aramid grades, including those that were subjected to heat treatment, while the skin-core interface was identified as the weak interface where failure may take place.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2019-12-01The student, Korhan Sahin, accepted the attached license on 2017-12-08 at 09:08.The student, Korhan Sahin, submitted this Dissertation for approval on 2017-12-08 at 09:38.This Dissertation was approved for publication on 2017-12-08 at 14:28.DSpace SAF Submission Ingestion Package generated from Vireo submission #11914 on 2018-03-13 at 10:37:53Made available in DSpace on 2018-03-13T17:35:51Z (GMT). No. of bitstreams: 11
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Prognostic significance of micropapillary pattern in lung adenocarcinoma and expression of apoptosis-related markers: caspase-3, bcl-2, and p53
No full textDemirag, Funda/0000-0003-4790-8369Cakir E, Yilmaz A, Demirag F, Oguztuzun S, Sahin S, Yazici UE, Aydin M. Prognostic significance of micropapillary pattern in lung adenocarcinoma and expression of apoptosis-related markers: caspase-3, bcl-2, and p53. APMIS 2011; 119: 574-80. We evaluated the clinicopathological characteristics and prognostic significance of lung adenocarcinoma with micropapillary pattern (MPP) and analyzed the expression of apoptosis-related markers: caspase-3, bcl-2, and p53. A series of 166 lung adenocarcinoma that had been surgically resected between 2004 and 2009 were reviewed. Histopathologic patterns, presence of tumor necrosis, mitosis, lymphovascular and perineural invasion, the status of pleura, and tumor differentiation were examined. Of the 166 patients; 71 were stage I, 35 stage II, 51 stage III, and nine stage IV. Histologically they were divided into two groups: MPP-positive (n = 55) and MPP-negative (n = 111). The following items were significantly more frequent in the MPP positive group: female gender (p = 0.03), lymph node metastasis (p = 0.031), and pleural invasion (p = 0.045). Age, smoking status, tumor stage, lymphatic invasion, perineural invasion, mitotic count, and survival rates had no statistically significant difference between groups (p > 0.05). In MPP positive tumors, visceral pleural invasion was identified significantly more frequent than in MPP negative tumors, at stage I. Tumors with MPP showed elevated expressions of caspase-3 (94.5%), p53 (60%), and bcl-2 (54.5%). In MPP positive group, the expression of these three markers had no statistically significant impact on survival. In whole population, bcl-2 expression was correlated with a better outcome. We conclude that MPP is associated with poor prognostic factors both in early and late stages in lung adenocarcinoma. Bcl-2 provides prognostic information independent from the MPP
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