Synthesis and characterization of chiral mixed ligand nanoclusters and nacre-structure

Nanoclusters gained attention due to their possible applications in biosensing, biolabeling, and optics. In this thesis we report the synthesis and characterization of mixed ligand silver nanoclusters that exhibit chiral behavior. We explored the occurrence of this behavior by changing the silver to thiol ratio, ratio of the ligands and using different ligands. Nacre-like structures are of interest due to their toughness that goes far beyond ceramic materials. This toughness arises from the layered structure which is kept together by biomolecules such that when stress is applied, the layers slide and entering the brittle regime is postponed. In addition, cracks cannot propagate in nacre due to organic/inorganic layering. To fabricate nacre-like materials, organic and inorganic layers are coated via layer-by-layer assembly or in situ biomineralization in an organic matrix is used. In this thesis we synthesized nacre-like layered nano/meso building blocks in a controlled and easy manner by the reduction of silver salt in the presence of two different ligands to produce nanoclusters, followed by a second reduction such that the nanoclusters assemble into a layered structure. We characterized the electronic, crystallographic, and optical properties of nacre-like structures

Nanoparticle Liposome Interactions

Protein-mimetic materials are of great interest for biotechnology to grant protein-like properties to artificial systems. Additionally, these materials can be used to shed light on the fundamental properties of proteins in many environments. Nanoparticles, in particular, offer a wide choice of parameters like size, core material, and surface chemistry that can be modified to better mimic proteins. Recently, it was shown that amphiphilic gold nanoparticles are able to fuse with and penetrate cell membranes in an energy independent manner. This behavior is similar to that of cell penetrating peptides. The objective of this thesis was to investigate the key parameters that allow amphiphilic nanoparticles to fuse with lipid bilayers and to generate nanoparticles capable of performing other protein-like functions. The thesis start with a systematic study on the interaction between amphiphilic gold nanoparticles and liposomes. All particles studied had a gold core, whose size varied from 1.7 to 6 nm. Amphiphilic ligand shells were achieved by using mixtures of a hydrophobic and hydrophilic ligand, with the hydrophobic one limited at 30% of the mixture because of solubility limitations. The liposomes studied had a size range of 60 to 300 nm. We found many different interactions. Sulfonated particles interacted with small vesicles (smaller than 60 nm) mediating clustering of vesicles, similar to adhesive proteins. The same particles, once combined with larger liposomes, behaved like curvature inducing proteins, that is they generated flat areas terminating in high curvature joints. Particles at the highest degree of amphiphilicity (i.e. a loading of the hydrophobic molecules at the limit of solubility), however, showed an even larger variety in interactions. The largest particles (~5 nm) fused with lipid membranes (independent on the liposome size) like cell penetrating peptides. Particles of intermediate size (~3 nm) fused with the membranes and brought liposomes in close proximity (like the less amphiphilic ones). These particles had an additional important property, they were able to mediate a fusion event upon Ca2+ addition between the adjacent liposomes. Hence these particles behaved as SNARE proteins and can be considered as the first synthetic material to be fusogenic. The smallest particles in this category fused with the lipid bilayer (as all others in this family), were fusogenic (as the middle sized ones) and spontaneously generated ring patterns on the liposomes. These rings where found to delimit flat vesicle regions. This latter phenomenon does not seem to have a biological analog. Overall, we find that amphiphilic nanoparticle can be considered as protein analogs, especially proteins that interact with membranes. In particular when the degree of amphiphilicity is high we achieved a series of particles that behave as membrane proteins, and depending on their size show different functions. These findings offer insight to decode the key factors in the interaction between nanoparticles and lipid bilayers and provide the first hints on how to use nanoparticles model systems to gain a better understanding on some key features of protein and protein functions

The Acute Effects of Velocity Loss During Half Squat Exercise on Jump Performance

The velocity loss (VL) approach during squat exercise may increase the post-activation potentiation enhancement effect on squat jump performance. If this method succeeds, then different conditions of VL should be researched before its implementation to the field. This study hypothesized that squat jump performance would be increased after different volumed VL conditions during half-squat exercise. Eighteen resistance-trained men (mean [M] ± standard deviation [SD]; age: 24.00±3.53 years; body mass: 78.37±5.53 kg; height: 179.35±7.04 cm; one-repetition maximum (1RM) half squat: 110.85±11.92 kg) voluntarily performed squat jump under unloaded and four different VL conditions (R6: six repetitions, Ruf: repetitions until failure, VL10: velocity loss thresholds 10%, VL20: velocity loss thresholds 20%) after a set of half-squat exercises at 80% of one-repetition maximum separated by at least 72 hours. The results revealed that subjects demonstrated significantly better squat jump performance in VL10, VL20, and R6 conditions than the unloaded and Ruf conditions (

Synthesis and characterization of mixed ligand chiral nanoclusters

Chiral mixed ligand silver nanoclusters were synthesized in the presence of a chiral and an achiral ligand. The ratio of the ligands was changed to track the formation of these clusters. While the chiral ligand lead to nanoparticles, Presence of the achiral ligand induced the formation of nanoclusters with chiral properties

Intraoral premalign ve malign lezyonlu hastaların doku örneklerindeki candida türlerinin DNA analiziyle belirlenmesi ve sağlıklı doku ile karşılaştırılması

Amaç: Bu retrospektif çalışmada premalign ve malign lezyonlu ile sağlıklı bireylere ait doku örneklerindeki Candida albicans, Candida kruseii, Candida parapsilosis, Candida tropicalis ve Candida glabrata türlerinin belirlenmesi amaçlanmıştır.  Gereç ve Yöntem: Çalışmaya oral premalign veya malign lezyon şüphesi nedeniyle biyopsi uygulanmış doku örnekleri dahil edildi. Örnekler histolojik özelliklerine göre sağlıklı (n=20), displazi (n=20), karsinoma in-situ (n=20) ve skuamoz hücreli karsinom (SHK) (n=20) olmak üzere 4 gruba ayrıldı. DNA izolasyonunun ardından Candida türlerine ait DNA örneklerinin miktar ve saflık kontrolleri gerçekleştirildi. Kantitatif ölçümler için Real-Time PCR (LightCycler 96, Almanya) kullanıldı ve standart eğriler hesaplandı. Veriler Mann-Whitney ve Wilcoxon Signed Ranks testleri ile değerlendirildi (P<0.05).Bulgular: Sağlıklı ve displazik örneklerin yer aldığı gruplarda C. parapsilosis (104DNA/50 mg) en sık görülen Candida türüydü. Karsinoma in-situ grubunda C. tropicalis ve C. kruseii (103DNA/50 mg), SHK grubunda ise C. kruseii (104DNA/50 mg) seviyelerinin daha yüksek olduğu belirlendi. Örneklerin hiçbirinde C. albicans varlığı gösterilemedi. Gruplar arasında farklı Candida türlerinin sayısına göre anlamlı bir fark gözlenmedi (P>0.05). Farklı Candida türlerinin gruplar içerisindeki seviyeleri incelendiğinde; sağlıklı örneklerde C. glabrata (103DNA/50 mg), displazi grubunda C. parapsilosis (104DNA/50 mg), karsinoma in-situ grubunda C. tropicalis-C. kruseii (103DNA/50 mg), SHK grubunda ise C. kruseii’nin (103DNA/50 mg) en fazla sayıda gözlenen Candida türü olduğu belirlendi. Candida türlerinin gruplar içerisindeki dağılımı anlamlı değildi (P>0.05).Sonuç: Sağlıklı, displazik, karsinoma in situ ve skuamöz hücreli karsinoma doku örneklerinde Real-Time PCR yöntemiyle yapılan kantitatif değerlendirmede Candida türlerinin tüm gruplarda benzer oranda mevcut oldukları belirlendi.ANAHTAR KELİMELER Oral Candida, C. albicans, ağız kanseri, Real-Time PCR, moleküler analiz &nbsp

Tuz katmanlı güneş havuzunun deneysel ve sayısal anali̇zi̇

A salt gradient solar pond (SGSP) is a low-cost solar energy system, collects incoming solar radiation and then stores it in the form of thermal energy. SGSP has been developed recently and is considered as a large-scale energy collector for long-term use with no or little maintenance. It also has no environmental hazard. Most importantly, solar energy meets the energy demand in a clean and sustainable way; thus, SGSP can be though as a sustainable alternative for conventional energy systems. SGSP has three zones. The first zone, located right below the surface, is called Upper Convective Zone (UCZ), it has both the lowest temperature and density since it contains fresh water. The second zone is Lower Convective Zone (LCZ), this is where the solar radiation is stored, yielding the highest temperature and density. Finally, the third zone is Non-Convective Zone (NCZ), which is placed between LCZ and UCZ, including water with different concentrations of salt. Solar radiation is mostly absorbed in the LCZ, which results in increasing water temperature in this zone. To facilitate the working principle of SGSP and store energy, it is very important to create and maintain temperature and density gradients. Temperature gradient depends on several factors, such as solar radiation, wind speed, and ambient temperature as well as the diameter of SGSP, and depth of each zone. The aim of this thesis is to investigate the experimental and numerical analysis of a solar pond. In the experimental analyses, performance evaluation of the solar pond is conducted based on experimental data, which includes solar radiation, wind speed, and ambient temperature. Based on the experimental analyses, it can be concluded that solar insolation, wind speed, and ambient temperature have coupled effects on pond temperature. Besides, it is known that obtaining high LCZ temperature is the main purpose of SGSP mechanism and during the experimentation, the maximum LCZ temperature was recorded to be 46ºC. According to the results, GHI has a more significant impact on controlling the temperature of the layers than ambient temperature and wind speed. After that, a numerical model is developed using the finite element method to conduct the parametric analyses to investigate each effect of parameters individually on the layer temperatures. Based on numerical results, UCZ and NCZ temperatures increase with increasing insolation, whereas LCZ mostly protects its temperature. Additionally, wind speed only affects UCZ temperature, and it does not a have profound effect on both NCZ and LCZ temperatures. The numerical results indicate that variation in ambient temperature has the highest impact on pond temperature among other variables. Besides, it is maintained that the diameter of SGSP does not affect the pond temperature. As future work, a more detailed transient model is required to examine the effects of layer thicknesses on pond temperature. Additionally, using transparent cover materials over the surface of the pond can be examined in detail; thus, the amount of stored sustainable energy in the lower layer might increase, which can directly increase the overall efficiency of a SGSP.Tuz katmanlı güneş havuzu, düşük bütçeli ve güneş enerjisine dayalı bir sistemdir. Gelen güneş enerjisini toplar ve termal enerji formunda depolanmasını sağlar. Uzun süreli kullanımda yüksek ölçekli enerji depolayıcısı olarak görülmesiyle birlikte, az bakım gerektirdiği ve çevreye zarar vermemesinden dolayı son zamanlarda geliştirilmekte olan bir sistemdir. Güneş enerjisi, enerji talebini temiz ve sürdürülebilir bir şekilde karşılar; bu yüzden günümüzde çoğunlukla kullanılan enerji kaynaklarına sürdürülebilir bir alternatif olarak düşünülebilir. Tuz katmanlı güneş havuzu üç ana bölgeden oluşmaktadır. Birincisi, hemen yüzeyin altında bulunan üst konvektif bölgedir ve sadece sudan oluştuğu için en düşük sıcaklık ve yoğunluğa sahiptir. İkinci katman, alt konvektif bölge, en yüksek sıcaklık ve yoğunluğa sahip olmakla birlikte, güneş enerjisinin depolandığı katmandır. Sonuncusu ise, alt ve üst konvektif katmanlar arasında bulunan ve farklı tuz derişimlerine sahip olan, konvektif olmayan bölgedir. Çoğunlukla alt tabakada absorbe edilen güneş enerjisi o bölgedeki sıcaklığın yükselmesiyle sonuçlanır. Sıcaklık ve yoğunluk değişiminin oluşturulması ve kontrol edilmesi, tuz katmanlı güneş havuzlarının çalışma prensibini anlamak açısından çok önemlidir. Elde edilen sıcaklık farkları; gelen güneş radyasyonuna, rüzgar hızına, hava sıcaklığına, buna ek olarak güneş havuzunun çapına ve her bir bölgenin derinliğine bağlıdır. Bu araştırmanın temel amacı, güneş havuzunun deneysel ve sayısal analizini incelemektir. Elde edilen deneysel verilere (güneş radyasyonu, rüzgar hızı ve hava sıcaklığı) göre güneş havuzunun performans değerlendirilmesi yapılmıştır. Deneysel analizlerde, gelen güneş ışığının, rüzgar hızının ve hava sıcaklığının birbirine bağlı olarak etkisi vardır. Bunun yanı sıra, tuz katmanlı güneş havuzunun temel amacı alt konvektif bölgede yüksek sıcaklık elde edebilmektir ve yapılan deneysel analizlere göre elde edilen maksimum alt konvektif bölge sıcaklığı 46ºC olarak bulunmuştur. Elde edilen sonuçlarda, güneş radyasyonunun katmanların sıcaklık değişimi üzerindeki etkisinin hava sıcaklığının ve rüzgar hızının etkisinden daha fazla olduğu gözlemlenmiştir. Daha sonrasında, gelen güneş ışığının, rüzgar hızının ve hava sıcaklığının etkilerini ayrı ayrı inceleyebilmek adına sayısal modelleme geliştirilmiştir. Elde edilen sonuçlara göre, üst ve orta katmanların sıcaklıklarının artan güneş radyasyonu ile artarken, alt katmanın genellikle sıcaklığını koruduğu gözlemlenmiştir. Buna ek olarak, rüzgar hızının sadece üst katmana etkisinin olduğu, orta ve alt katmanlarda önemli bir etkisinin olmadığı gözlemlenmiştir. Sayısal modelleme sonuçları, katmanların sıcaklığının değişmesinde en fazla etkinin değişen hava sıcaklığıyla elde edildiğini göstermiştir. Bunun dışında yapılan sayısal analizlerde, güneş havuzunun çapının artıp azalmasının katman sıcaklıklarında herhangi bir değişiklik yapmadığı bulunmuştur. Katmanların kalınlığının güneş havuzu sıcaklık değişimleri üzerindeki etkilerini daha iyi değerlendirebilmek için daha detaylı bir modelleme oluşturulması ilerideki çalışmalar için planlanmaktadır. Ek olarak, güneş havuzunun yüzeyini geçirgen maddelerle kaplamak detaylı bir şekilde incelenebilir; böylece alt katmanda depolanan sürdürülebilir enerji miktarı artabilir ve bu da doğrudan güneş havuzunun veriminin artmasıyla sonuçlanabilir.M.S. - Master of Scienc

Effect of helfer skin tap tecnique on pain associated with intramuscular injection among adult: A randomized controlled study

Abstract-Objective:The purpose of this study was to determine the effects of Helfer skin tap technique (HSTT) on pain depending on intramuscular (IM) injection.Methods:The study was randomized controlled study in the injection polyclinic between September18 andDecember9 2017. The study was completed with totally 100 patients, 50 of them in the experimental group and 50 of them in the controlgroup. The IM injection was applied to the experimental group by HSTT and to the control group by standard technique. Data were collected using a questionnaire and Visual Analog Scale (VAS).Results:The mean VAS score was differ between groups. The VAS score reduced significantly after HSTT intervention in experimental group whereas reduction was not significant in controlgroup.Conclusions:The study showed that HSTT was effective on pain depending on IM injectio