Benzin direk enjeksiyon spreyleri üzerine nümerik çalışma

Thesis (Master)--Izmir Institute of Technology, Energy Engineering, Izmir, 2015Includes bibliographical references (leaves. 66-71)Text in English; Abstract: Turkish and Englishxiii, 73 leavesGasoline direct injection technology is a combination of the advantages of diesel engine and spark ignition engines. Hence, the gasoline fuel is injected directly to combustion chamber. It provides finer atomization to allow evaporation more rapidly than traditional gasoline engines and less emissions in terms of NOx and particulate than diesel engines. The understanding of spray behaviour is a significant point to control optimal air/fuel mixture and misfiring. This thesis presents a numerical investigation of a GDI injector under flash and non-flash boiling conditions. The study is performed with sprays injected into a constant volume chamber. The purpose of the thesis is to develop a CFD model to compare it with experimental spray penetration and spray angle results. Firstly, the model is validated in terms of spray penetration. Secondly, the model is applied to nine different conditions including flash and non-flash boiling conditions. The spray penetration and angle comparisons between numerical and experimental results were done.Benzin direk enjeksiyon teknolojisi, dizel enjeksiyon ile benzin motorlarının avantajlarının bir kombinasyonudur. Benzin direk motorlarında direk olarak benzin yanma odasına püskürtülür. Bu hem daha küçük damlacıklara ayrılmasına bu sayede hızlıca buharlaşmasına ve dizel motorlara gore NOx ve katı madde emisyonlarının daha az olmasına olanak sağlar. Spreyin davranışını anlamak optimum yakıt-hava karışımı açısından önemlidir. Bu tez, direk benzin enjektör spreylerinin flash boiling ve olmayan koşullardaki nümerik çalışmasını sunmaktadır. Bu tezin amacı, deneysel sprey penetrasyonu ve sprey açısı sonuçlarıyla kıyaslama yapabilmek için bir CFD model geliştirmeyi amaçlamaktadır. Öncelikle model sprey penetrasyonu ile doğrulandı. Daha sonra, modelde flash ve flash boiling olmayan koşulları içeren dokuz farklı işletme koşulları uygulandı. Nümerik ve deneysel sprey açısı ve sprey penetrasyon sonuçları karşılaştırıldı

Benzin direk enjeksiyon spreyleri üzerine nümerik çalışma

Thesis (Master)--Izmir Institute of Technology, Energy Engineering, Izmir, 2015Includes bibliographical references (leaves. 66-71)Text in English; Abstract: Turkish and Englishxiii, 73 leavesGasoline direct injection technology is a combination of the advantages of diesel engine and spark ignition engines. Hence, the gasoline fuel is injected directly to combustion chamber. It provides finer atomization to allow evaporation more rapidly than traditional gasoline engines and less emissions in terms of NOx and particulate than diesel engines. The understanding of spray behaviour is a significant point to control optimal air/fuel mixture and misfiring. This thesis presents a numerical investigation of a GDI injector under flash and non-flash boiling conditions. The study is performed with sprays injected into a constant volume chamber. The purpose of the thesis is to develop a CFD model to compare it with experimental spray penetration and spray angle results. Firstly, the model is validated in terms of spray penetration. Secondly, the model is applied to nine different conditions including flash and non-flash boiling conditions. The spray penetration and angle comparisons between numerical and experimental results were done.Benzin direk enjeksiyon teknolojisi, dizel enjeksiyon ile benzin motorlarının avantajlarının bir kombinasyonudur. Benzin direk motorlarında direk olarak benzin yanma odasına püskürtülür. Bu hem daha küçük damlacıklara ayrılmasına bu sayede hızlıca buharlaşmasına ve dizel motorlara gore NOx ve katı madde emisyonlarının daha az olmasına olanak sağlar. Spreyin davranışını anlamak optimum yakıt-hava karışımı açısından önemlidir. Bu tez, direk benzin enjektör spreylerinin flash boiling ve olmayan koşullardaki nümerik çalışmasını sunmaktadır. Bu tezin amacı, deneysel sprey penetrasyonu ve sprey açısı sonuçlarıyla kıyaslama yapabilmek için bir CFD model geliştirmeyi amaçlamaktadır. Öncelikle model sprey penetrasyonu ile doğrulandı. Daha sonra, modelde flash ve flash boiling olmayan koşulları içeren dokuz farklı işletme koşulları uygulandı. Nümerik ve deneysel sprey açısı ve sprey penetrasyon sonuçları karşılaştırıldı

Investigation of catechol-o-methyltransferase (comt) gene Val158Met polymorphism in ovarian cancer

Objective: Catechol-o-methyltransferase (comt), the product of the COMT gene, detoxifies the carcinogenic catechol estrogens. The aim of the present study was to examine the relationship between comt Val158Met polymorphism and the risk of ovarian cancer. Material and methods: The study groups consist of 94 individuals as a patients group with ovarian cancer (n=47) and control group (n=47). The allele and genotype frequencies were determined according to Hardy-Weinberg equilibrium (HWE). The allele and genotype frequencies. determined according to HWE. Genetic analysis were performed by real-time-polymerase chain reaction instrument, and the statistical analysis were performed by SPSS program. Results: Although no significant relationship was obtained among groups (p=0.413) regarding comt gene Val158Met polymorphism, the genotype frequencies for comt Val158Met (rs4860) polymorphism in groups was homozygote wild type GG genotype 25.5%, heterozygote GA genotype 46.8%, homozygote mutant AA genotype 27.7%. Conclusion: This study is the first to investigate the relationship between ovarian cancer and the Val158Met polymorphism in the comt gene in a Turkish population. No statistically significant relationship was identified among genotypes belonging to the patient and control groups although sample sizes were relatively small and the analysis should be repeated in a larger cohort.No sponso

Synergistic Effect of Gemcitabine and Clofazimine in Co-loaded Liposomal Formulation for Multidrug Treatment Approach of Osteosarcoma

ntroduction: Osteosarcoma is the most common cancer in bone with high occurrence in children. The development of resistance is a challenge of current treatment strategies that needs to be improved with novel treatment strategies. In the current research, a new dual drug delivery system was developed with Gemcitabine (GEM) and Clofazimine (CLF) co-loaded liposome formulations for osteosarcoma treatment. GEM is a pyrimidine antimetabolite that inhibits DNA synthesis and CLF is a leprostatic and anti-inflammatory drug that has been recently recognized as effective on cancer. Liposomal formulation of GEM and CLF was prepared using advantage of their specific localization in liposome; hydrophilic GEM being loaded into core and lipophilic CLF sequestering in hydrophobic lipid-bilayer. It is the first time that CLF is evaluated for its cytotoxicity on bone cancer cells and investigated for its synergistic effect with GEM on osteosarcoma. Methods: PEGylated liposomal formulations were prepared with DPPC:CHOL:DSPE-PEG (2000) lipids. They were investigated for their GEM and CLF encapsulation and loading efficiencies, in vitro release profiles, particle size, zeta potential and morphological properties. The cytotoxicity of liposome formulations were investigated by MTT assay on Saos-2 cells. Flow cytometry analyses were done to determine apoptotic effects of GEM, CLF and their co-loaded liposome groups on Saos-2 cells. Results: Characterization studies showed high encapsulation efficiency and loading of both GEM and CLF in liposome formulations. CLF release was enhanced while GEM release was slowed down in co-loaded formulations compared to their single loaded cases. Size of all liposomal formulations were under 200 nm and zeta potential values were slightly negative. All GEM/CLF co-loaded liposomal formulations showed significantly enhanced cytotoxicity than GEM loaded and CLF loaded liposome treatments. Use of CLF with GEM was found to have synergistic effect (CI<1) according to CompuSyn analysis. Results of flow cytometry experiments showed higher apoptotic cell ratio upon GEM/CLF co-loaded liposome treatments compared to other liposome treatment groups. Conclusion: Novel liposome formulation of GEM/CLF co-loaded liposome was successfully presented for the first time in this study. CLF’s single or co encapsulation with GEM into liposome was a new approach for enhancement of anticancer effect on Saos-2 cells. This formulation is thought to bring further advantages in terms of decreased side effects with the CLF contribution. It is also expected to provide specific therapeutic benefits of liposomal formulations. Therefore, GEM/CLF co-loaded liposomal delivery system is proposed to bring a novel approach for treatment of osteosarcoma

Computer-assisted videokeratographic analysis of phacoemülsification applied eyes

AMAÇ: Fakoemülsifikasyon ile göz içi mercek (GİM) implantasyonu uygulanan hasta kornealarında, korneal topografik analiz için çalışma grubu oluşturuldu. GEREÇ VE YÖNTEM: Çalışma grubunu fakoemülsifikasyon ile katlanabilir, 5.0 mm, yada 6,5 mm'lik G/M implante edilen 224 olgunun 271 gözü oluşturdu. Bu grubun yaş ortalaması 63.1 ± 11.8 (14-90) idi. Postoperatif 1. gün, 1. hafta ve 1. ay surface regularity index (SRI), surface asymmetry index (SAI), simulated keratometry (SimK1, SimK2) ve minimum keratometrik value (MinK) ortalama değerleri, preoperatif değerlerle karşılaştırıldı. BULGULAR: Sonuçta 6.5 mm GİM'i uygulanan olguların, preoperatif ve postoperatif l.gün SRI değerleri dışında istatistiksel anlamlı fark saptanmadı. GİM uygulanan olguların tümünde postoperatif 1. gün SRI, SAI ortalama değerleri, preoperatif değerlerine göre yüksek iken, postoperatif 1. ayda yaklaşık preoperatif değerler düzeyine düştü. Her üç insizyon tipinde de 1 ay sonunda SimK1, SimK2 ve MinK ortalama değerlerinde istatistiksel olarak anlamlı farklılık saptanmadı. SONUÇ: Operasyon sırasında 6.5mm ye genişletilen tünel insizyonlann korneada kalıcı ciddi astigmatik değişiklikler oluşturmadığı kanısına varıldı.PURPOSE: We evaluated the topographic analysis of corneas in patients who underwent phacoemulsification and intraocular lens (IOL) implantation. MATERIAL AND METHOD: The group consisted of 271 eyes of 224 eases who underwent foldable, 5.0 mm or 6.5 mm IOL implantation following phacoemulsification, The mean age of this group was 63.1 ±11.8 (14-90). in this group the surface regularity index (SRI), surface asymmetry index (SAI), simulated keratometry (SimK1, SimK2) and minumum keratometric value (Min K) were evaluated using quantitative corneal topographic indices, the findings at the preoperative period were compared with the values at the postoperative day, 1 st week and 1 st month. RESULTS: As the result, we did not observe statistical difference except the SRI values of 6.5 mm IOL implanted cases at the postoperative 1st day. The SRI and SAI values were found to be higher at the postoperative 1st day in comparison to the preoperative values whereas it decreased to the preoperative values at the postoperative 1st month. CONCLUSION: It has been concluded that the tunnel incisions uridened up to 6.5 mm during the operation did not cause significant astigmatic changes in the cornea