Effect of different impression materials on the marginal fit of frameworks: An in-vitro study

Objectives: The objective of this study was to compare the accuracy of three different impression materials with evaluating the marginal fits of metal frameworks using replica technique.Materials and Methods: A phantom premolar tooth was prepared with a 1 mm circumferential chamfer preparation. Four impression materials: two vinyl polysiloxane (VPS) (Affinis Precious, (Group A); Elite HD, (Group E)), one polyether (Impregum Penta Soft, (Group P)) and one vinyl siloxanether (Identium, (Group I)) were used for producing stone casts of this master model. Twelve measurements per replica were carried out using a light microscope X40 magnification by Leica software, to assess the vertical marginal gap (VMG). Data were analyzed using the analysis of variance followed by Tukey’s test (p=0.05).Results: Specimens of the Group A and I showed significantly lower VMG values than those of Group E and Group P (p<0.001). Differences were not significant between groups A and I, and E and P either (p>0.05).Conclusions: All impression materials were clinically acceptable. As well as composition of the impression materials, size of filler particles and fluid mechanics of flow into very small spaces can be effective on accuracy of the materials

Temperature and pH-dependent behaviors of mAb drugs: A case study for trastuzumab

The distortions in the high-order structure of therapeutic monoclonal antibodies (mAbs) under different environmental conditions acutely affect mAb stability, resulting in altered safety, efficacy, and shelf-life profiles. The overall stability of mAbs depends on many factors, and it requires complementary techniques for an in-depth analysis. The stability of mAbs can be characterized by differential centrifugal sedimentation (DCS), differential scanning calorimetry (DSC), differential scanning fluorimetry (DSF), and size exclusion chromatography (SEC) techniques. In this report, temperature-ramped dynamic light scattering (DLS), and circular dichroism (CD) spectroscopy were employed as complementary tools to show how temperature and pH affect the aggregation of a model mAb, trastuzumab, in solution. The results showed that the aggregation onset temperature of trastuzumab defined by DLS was 75 degrees C, which decreases the amount of beta-sheets and causes a slight increase in helix structures. Moreover, the melting temperature of trastuzumab was determined to be between 80-83 degrees C by temperature-ramped CD spectrophotometry, which is in line with the Tm of trastuzumab's Fab region tested with DSC. Thus, unfolding and aggregation of trastuzumab start simultaneously at 75 degrees C, and unfolding triggers the aggregation. The temperature-ramped CD and DLS methods are robust tools to determine the thermal behavior of biosimilars in various solution conditions. Their complementary usage provides solid scientific background for regulatory applications and a better understanding of mAb instability and its relationship with structural changes

Plasmonic titanium nitride nanohole arrays for refractometric sensing

Group IVB metal nitrides have attracted great interest as alternative plasmonic materials. Among them, titanium nitride (TiN) stands out due to the ease of deposition and relative abundance of Ti compared to those of Zr and Hf metals. Even though they do not have Au or Ag-like plasmonic characteristics, they offer many advantages, from high mechanical stability to refractory behavior and complementary metal oxide semiconductor-compatible fabrication to tunable electrical/optical properties. In this study, we utilized reactive RF magnetron sputtering to deposit plasmonic TiN thin films. The flow rate and ratio of Ar/N2 and oxygen scavenging methods were optimized to improve the plasmonic performance of TiN thin films. The stoichiometry and structure of the TiN thin films were thoroughly investigated to assess the viability of the optimized operation procedures. To assess the plasmonic performance of TiN thin films, periodic nanohole arrays were perforated on TiN thin films by using electron beam lithography and reactive ion etching methods. The resulting TiN periodic nanohole array with varying periods was investigated by using a custom microspectroscopy setup for both reflection and transmission characteristics in various media to underline the efficacy of TiN for refractometric sensing.101111321 ; EP/Y030273/

Example Generation Abilities Of High School Students Within The Context Of Mathematics Course

In this study example generation abilities of high school students were examined within the context of mathematics course. The study in which used qualitative research method was carried out as a case study. The participants of the study are 129 students consist of 83 girls and 46 boys being educated in 2015-2016 academic year at a high school. As data collection tools example generation questions about topics taught before were formed to students. Withal it has been interviewed with 22 students as individual to analyse in-dept example generation processes of students. Students who taked part in interwiev were choosen with aimed sample technique according to answers given in application of example generation and mathematics course success evaluation. During the interview students were asked to say the reasons for the answers given before and write if they have new thaughts on their application papers. Also this interviews were recorded with the students permission. Obtained datas were examined with content analysis method. At the end of the study, it was determined that most of the students used trial and error strategy during example generation process and analysis strategy which needs top level cognitive ability wasn’t used by students. İt was observed that some of students concept image corresponded to nothing mathematically and a part of students didn’t have any concept image. Data analysis also indicated that many of students have misconceptions because of limited example spaces and concept knowledges and only procedural learning isn’t enough at the example generation activities. At the last part of this study suggestions are made for researchers, mathematics curriculum developers and educators.JÜRİ ONAY BİLDİRİMİ .......................................................................................... ii YAYIMLAMA VE FİKRİ MÜLKİYET HAKLARI BEYANI......................................... iii ETİK BEYANNAMESİ ........................................................................................... iv TEŞEKKÜR............................................................................................................ v ÖZ......................................................................................................................... vi ABSTRACT..........................................................................................................viii İÇİNDEKİLER ........................................................................................................ x ÇİZELGELER DİZİNİ ........................................................................................... xii ŞEKİLLER DİZİNİ ................................................................................................xiii SİMGELER VE KISALTMALAR DİZİNİ ................................................................ xv 1. GİRİŞ ............................................................................................................1 1.1. Problem Durumu .........................................................................................1 1.2. Araştırmanın Amacı ve Önemi:....................................................................4 1.3. Problem Cümlesi: ........................................................................................6 1.3.1. Alt Problemler:.......................................................................................6 1.4. Sayıltılar: .....................................................................................................6 1.5. Sınırlılıklar: ..................................................................................................6 1.6. Tanımlar: .....................................................................................................7 1.7. Araştırmanın Kuramsal Temeli ....................................................................8 1.7.1 Örnek Kavramı ve Örneklerin Matematik Eğitimindeki Yeri ...................8 1.7.2 Örneklerin Sınıflandırılması..................................................................12 1.7.3 Öğretmen Açısından Örnekler .............................................................16 1.7.4 Öğrenci Açısından Örnekler .................................................................21 1.7.5 Kişisel Örnek Uzayı.............................................................................24 1.7.5.1.Örnek Uzayının Gelişimi İçin Pedagojik Araç.................................28 1.7.6 Kavram Tanımı ve Kavram İmajı ..........................................................32 1.7.7 Kavram Yanılgısı..................................................................................39 1.7.8 İşlemsel Öğrenme ve Kavramsal Öğrenme ..........................................42 1.7.9 Matematiksel Kavramların İfade Edilmesi............................................43 1.7.10 Örnek Üretme Süreci ve Stratejileri ....................................................44 2. İLGİLİ ARAŞTIRMALAR...................................................................................56 3. YÖNTEM..........................................................................................................60 3.1. Araştırmanın Yöntemi ................................................................................60 3.2. Çalışma Grubu ..........................................................................................60 3.3. Veri Toplama Araçları ................................................................................62 3.3.1. Yazılı Dökümanlar...............................................................................62 3.3.2. Görüşmeler .........................................................................................64 3.4. Veri Toplama Araçlarının Uygulanışı .........................................................65 3.5. Verilerin İşlenmesi ve Çözümlenmesi ........................................................66 3.6. Araştırmanın Geçerliği...............................................................................67xi 3.7. Araştırmanın Güvenilirliği...........................................................................68 4. BULGULAR VE TARTIŞMA .............................................................................70 4.1 Öğrencilerin Kullandıkları Örnek Üretme Stratejileri....................................70 4.1.1 Deneme Yanılma Stratejisi...................................................................72 4.1.2 Dönüştürme Stratejisi...........................................................................74 4.1.3 Analiz Stratejisi.....................................................................................75 4.2 Örnek Üretme Becerisinde Kavram İmajlarına Yönelik Bulgular .................76 4.3 Örnek Üretme Becerisinde Örnek Uzay Genişliğine Yönelik Bulgular.........80 4.4 Örnek Üretme Becerisinde Kavram Yanılgılarına Yönelik Bulgular .............82 4.5 Örnek Üretme Becerisinde İşlemsel Öğrenme ve Kavramsal Öğrenmeye Yönelik Bulgular .....................................................................84 5. SONUÇ ve ÖNERİLER ....................................................................................88 5.1. Sonuçlar ....................................................................................................88 5.2. Öneriler......................................................................................................90 5.2.1. Araştırmaya Dönük Öneriler ................................................................91 5.2.2. Uygulamaya Dönük Öneriler ...............................................................91 KAYNAKÇA .........................................................................................................94 EKLER DİZİNİ....................................................................................................104 EK 1. ETİK KURUL ONAY BİLDİRİMİ................................................................105 EK 2. UYGULANMASI PLANLANAN ÖRNEK ÜRETME SORULARI.................106 EK 3. 9.SINIF ÖRNEK ÜRETME PİLOT UYGULAMA SORULARI.....................107 EK 4. 10.SINIF ÖRNEK ÜRETME PİLOT UYGULAMA SORULARI...................108 EK 5.ÖRNEK ÜRETME UYGULAMA SORULARI ARASINDAN ÇIKARTILAN SORULAR.......................................................................................109 EK 6. 9.SINIF ÖRNEK ÜRETME UYGULAMA SORULARI................................110 EK 7. 10.SINIF ÖRNEK ÜRETME UYGULAMA SORULARI..............................112 EK 8. 11.SINIF ÖRNEK ÜRETME UYGULAMA SORULARI..............................114 EK 9. 12.SINIF ÖRNEK ÜRETME UYGULAMA SORULARI..............................116 EK 10. YARI YAPILANDIRILMIŞ GÖRÜŞME FORMU ......................................118 EK 11. ORJİNALLİK RAPORU...........................................................................119 ÖZGEÇMİŞ........................................................................................................121Bu çalışmada lise öğrencilerinin matematik dersindeki örnek üretme becerileri incelenmiştir. Nitel araştırma yöntemi kullanılarak yürütülen bu araştırma durum çalışması şeklinde gerçekleştirilmiştir. Araştırmanın çalışma grubunu bir orta öğretim kurumunun 2015-2016 eğitim-öğretim yılında öğrenim gören 83’ü kız, 46’sı erkek olmak üzere toplam 129 öğrenci oluşturmaktadır. Veri toplama aracı olarak öğrencilere daha önce işledikleri konularla ilgili örnek üretme soruları uygulanmış ve öğrencilerin örnek üretme süreçlerini derinlemesine analiz edebilmek için çalışma grubundan 22 öğrenci ile birebir görüşme yapılmıştır. Görüşmeye katılacak öğrenciler uygulama sorularına verilen cevaplar ve matematik dersi başarı durumu değerlendirmesine göre amaçlı örnekleme yöntemi ile belirlenmiştir. Görüşme esnasında öğrencilerden sorulara verdikleri cevapların nedenlerini söylemeleri ve bu bağlamda (varsa) yeni düşüncelerini kendilerine ait olan uygulama formlarına aktarmaları istenmiştir. Ayrıca yapılan bu görüşmeler öğrencilerin izniyle ses kaydına alınmıştır. Elde edilen veriler içerik analizi yöntemi ile analiz edilmiştir. Araştırmanın sonucunda öğrencilerin örnek üretirken daha çok deneme yanılma stratejisini kullandığı üst düzey düşünme becerisi gerektiren analiz stratejisini ise kullanamadıkları belirlenmiştir. Öğrencilerin bazılarında yer alan kavram imajlarının matematiksel olarak bir karşılığının olmadığı bir kısmında ise herhangi bir kavram imajının bulunmadığı görülmüştür. Yeterli seviyede kavram bilgisi ve örnek uzaya sahip olmamaları nedeniyle öğrencilerde kavram yanılgılarının oluştuğu; örnek üretme etkinliklerinde işlemsel öğrenmenin tek başına yeterli olmadığı çıkarılan diğer sonuçlardır. Araştırmanın son bölümünde araştırmacılara, matematik program geliştiricilerine ve eğitimcilere yönelik önerilere yer verilmiştir

Lise öğrencilerinin matemaik dersi kapsamında örnek üretme becerilerinin incelenmesi

Examples are an indispensable part of mathematical thinking through analogy, learning and the teaching process. In this study, the strategies that high school students used in example generation activities in mathematics course; operational and conceptual knowledge levels were determined and their effect on example generation ability was examined. The working group of the study was designed as a case study that followed a qualitative research method; the study consisted of 22 students attending high school in the 2016-2017 academic year. As a data collection tool, example generation questions were administered to the students. To analyze students' example generation processes in depth, semi-structured interviews were conducted and data obtained from the interviews were analyzed using a content analysis method. The results showed that the students used trial and error strategy more than transformation strategy while generating examples but no finding of analysis strategy was obtained. Factors affecting the students' example generation skills negatively included the lack of a mathematical equivalent of the concept images related to the topics covered by the questions and their not having a high enough level of concept knowledge. Results also indicated that conceptual knowledge had a positive effect on the ability to generate examples. Keywords: example generation, conceptual knowledge, procedural knowledg

BİLGİSAYAR DESTEKLİ TASARIM-BİLGİSAYAR DESTEKLİ ÜRETİM VE PRESLEME SİSTEMLERİYLE ÜRETİLEN PORSELEN LAMİNAT VENERLERİN KENAR VE İNTERNAL UYUMLARININ KARŞILAŞTIRILMASI: İN-VİTRO ÇALIŞMA

Aim: The aim of this study was to evaluate the marginal and internal adaptations of porcelain laminate veneers produced with Computer aided design-Computer aided manufacturing and Heat-pressed techniques. Material and Methods: A total of 40 porcelain laminate veneers were evaluated whether the marginal and internal adaptations are changed due to fabrication technique. The veneers were fabricated with Computer aided design-Computer aided manufacturing and Heatpressed techniques (n=20). The marginal and internal adaptations of veneers were measured by using a replica technique. Replicas of each veneer were obtained by using a light-body silicone impression material. The replicas were sectioned mesio-distally and gingivoincisally. Then the marginal and internal gap adaptation of each cross section were measured by a stereomicroscope at x40 magnification. Nine measurement locations for internal, 3 measurement locations for marginal adaptation were used to obtain the mean values. Levene and independent samples t-test was used to identify the statistical difference among the groups (p0.05). Results: The mean marginal adaptation values of Heatpressed and Computer aided design-Computer aided manufacturing veneers were 269±136.92 ?m and 192± 61.02 ?m respectively. There was a significant difference between the values (p=0.028). A significant difference was found between the internal adaptation values of Heat-pressed (190.43±63.33 ?m) and Computer aided design-Computer aided manufacturing veneers (105.61± 24.39 ?m) (p=0.00). Conclusion: Within the limitations of this in-vitro study, the Computer aided design-Computer aided manufacturing veneers showed statistically better marginal and internal adaptation values than the Heat-pressed veneersAmaç: Çalışmanın amacı, Bilgisayar destekli tasarımBilgisayar destekli üretim ve Isı ile Presleme yöntemleriyle üretilmiş porselen laminat venerlerin kenar ve iç yüzey uyumlarının karşılaştırılmasıdır. Gereç ve yöntem: Kenar ve iç yüzey uyumlarının fabrikasyon tekniğine göre farklılık gösterip göstermediğini belirlemek amacıyla toplam 40 adet porselen laminat vener değerlendirildi. Venerler, Bilgisayar destekli tasarım-Bilgisayar destekli üretim ve Isı ile Presleme yöntemleriyle üretildi (n=20). Kenar ve iç yüzey uyumları replika tekniği kullanılarak değerlendirildi. Her bir venerin replikası akışkan kıvamlı elastomerik ölçü materyali kulanılarak alındı ve replikalar, meziyo-distal ve insizo-gingival yönde kesildi. Her bir kesitin iç yüzey ve kenar uyumları ışık mikroskobunda x40 büyütme kullanılarak ölçüldü. İç yüzey uyumu için 9 nokta, kenar uyum içinse 3 nokta ölçüldü ve ortalamaları alındı. Levene ve independent samples t testi kullanılarak istatistiksel analiz yapıldı (p0,05). Bulgular: Isı ile Presleme sistemi ile üretilen venerlerin kenar aralık değerleri (269±136,92 ?m), Bilgisayar destekli tasarım-Bilgisayar destekli üretim ile üretilenlere (192±61,02 ?m) göre daha yüksektir (p= 0,028). İki yöntemin iç yüzey aralık değerleri karşılaştırıldığında yine, Isı ile Presleme sistemi ile üretilen venerlerin iç yüzey aralık değerleri (190,43±63,33 ?m), Bilgisayar destekli tasarım-Bilgisayar destekli üretim ile üretilenlere (105,61±24,39 ?m) göre daha yüksektir (p=0,00). Sonuç: Bu çalışmanın kısıtlamaları dahilinde, Bilgisayar destekli tasarım-Bilgisayar destekli üretim yöntemi ile üretilen porselen laminat venerlerin kenar ve iç yüzey uyumları, Isı ile Presleme sistemi ile üretilenlere göre daha iyidi

Inhibition effect of 2-amino-4-methylpyridine on mild steel corrosion: Experimental and theoretical investigation

The effect of 2-amino-4-methylpyridine (AMP) on the corrosion behavior of mild steel (MS) in 0.5. M HCl is investigated with electrochemical methods and theoretical calculations. The electrochemical tests show that the polarization resistance of MS increasing the presence of AMP in acid solution. Adsorption of AMP on MS surface is a physical and obeys the Langmuir isotherm. The quantum parameters signaled adsorption occurs on amine and methyl substituents of AMP. The inhibition efficiency is related to frontier orbital's energy band gap of AMP, which are 5.357 and 6.490. eV for neutral and protonated molecules in aqueous solution, respectively. © 2014 Elsevier Ltd

Effect of different impression materials on the marginal fit of frameworks: An in-vitro study

Objectives: the objective of this study was to compare the accuracy of three different impression materials with evaluating the marginal fits of metal frameworks using replica technique. Materials and Methods: A phantom premolar tooth was prepared with a 1 mm circumferential chamfer preparation. Four impression materials: two vinyl polysiloxane (VPS) (Affinis Precious, (Group A); Elite HD, (Group E)), one polyether (Impregum Penta Soft, (Group P)) and one vinyl siloxanether (Identium, (Group I)) were used for producing stone casts of this master model. Twelve measurements per replica were carried out using a light microscope X40 magnification by Leica software, to assess the vertical marginal gap (VMG). Data were analyzed using the analysis of variance followed by Tukey’s test (p=0.05). Results: Specimens of the Group A and Group I showed significantly lower VMG values than those of Group E and Group P (p0.05). Conclusions: All impression materials were clinically acceptable. As well as composition of the impression materials, size of filler particles and fluid mechanics of flow into very small spaces can be effective on accuracy of the material