This study focuses on experimental modelling of the failure of Thermal Barrier Coatings (TBCs) due to attack of CMAS (Calcia-Magnesia-Alumina-Silicate), which is often found in harsh environments, via glassy phase infiltration. Volcanic ash and dust, sand particles, and fly ash, which contain CMAS, are imminent threats impeding predictable lifetimes of TBCs. Such incurrence directly affects the geometry and clinging to bond coat, and intrinsic material properties such as thermal conductivity and crystal structure of TBC are modified after exposure to CMAS, which ultimately results in delamination, spallation and failure of the coating material. The scope of this work is to survey the reactivity of CMAS with various oxide systems, and evaluate possible oxide systems that can be replaced and/or used with Yttria-stabilized Zirconia (YSZ) by investigating the penetration depth and reactivity after sintering with CMAS. A cost-effective method to observe the reaction of candidate oxides with CMAS is suggested and administired; understanding the main mechanism that causes the failure of top coat in the wake of CMAS infiltration, and seeking solutions for the problem is performed by taking advantage of Scanning Electron Microscopy (SEM). Recently suggested ceramic oxide systems that form in pyrochlore structure, some perovskite structures in various compositions, monazite, mullite and YSZ are studied. The possible outcome consequent upon CMAS infiltration are concluded and course for designing novel material systems that are expected to withstand the CMAS attacks better than the state-of-the-art 4mole% YSZ is defined. 5% mole Yb-doped SrZrO3(5Yb-SZ) and favored pyrochlores such as Gd2r2O7 and GdYbZr2O7 are found to be better mitigating CMAS attacks.

Arsenic is a metalloid member of heavy metals associated with many health problems from various cancers to skin diseases. Due to mankind activities and natural sources, arsenic contamination seen globally. More than 150 million people globally face with arsenic via arsenic polluted ground water. It is well known that speciation of arsenic is important for its actions inside of the exposed organism. Saccharomyces cerevisiae, is one of six model organisms, provides an general answer for the question “What eukaryotes do?”. So assessing some questions on budding yeast gives a general idea about potential results in other eukaryotes including human. One of the issues investigated on this yeast is that impacts and metabolism of arsenic. Arsenic is well studied on Saccharomyces cerevisiae and consequently much data became available. In this review, cellular impacts of arsenic and response of the yeast towards arsenic exposure is covered.

Peptit nükleik asitler (PNA), tekrarlayan N-(2-aminoetil) glisin birimlerinin peptit bağlarıyla bağlanmış olduğu bir omurgaya sahip, pürin ve pirimidin nükleobazlarının bu omurgaya metilen karbonil bağları ile bağlandığı, DNA'nın sentetik analoglarıdır. PNA, nükleik asitlere göre üstün hibridizasyon ve geliştirilmiş kimyasal ve enzimatik stabilite gibi çok yönlü özellikleri nedeniyle, teşhis ve farmasötik alanlarda büyük potansiyel taşımaktadır. Bununla birlikte, PNA kullanımında en önemli kısıtlama, hücre içine alınımındaki zorluğudur. Bu nedenle, PNA'nın hücre içine alınımını arttırmak için bazı farklı giriş mekanizmaları geliştirilmektedir. Antisens peptid nükleik asit (PNA) oligomerleri, temel gen ekspresyonunun spesifik olarak azaltılması yoluyla bakteriyel büyümeyi önleyen yeni bir potansiyel antibiyotik sınıfı oluşturur. Antisens olarak etki göstermesinin yanı sıra PNA’nın, birçok araştırmada prob amaçlı olarak kullanımı da mevcuttur. Gen düzenleme gibi daha terapötik uygulamalarda, spesifik genom modifikasyonları oluşturmak için de kullanılmaktadır. Bu derleme, PNA'nın yapısını, özelliklerini ve ayrıca veteriner hekimlik alanında kullanılan uygulamalarını kısaca sunmaktadır