The influence of process parameters on filament size distribution

Filaments are formed at the exit of rolling nips in some coating and printing operations. The filament size distribution can determine product quality such as gloss. The average filament size is linked to operational difficulties such as misting. The filament size distribution of various fluids and inks is characterized and compared to theoretical model. A high-speed video camera is used to visualize the exit of a rolling nip. The size distribution of the filaments is characterized with image analysis. A laboratory print tester is used with the high speed camera to characterize the size of the defects right after printing. The rheological properties are obtained using a cone and plate rheometer. A novel test is developed characterize the fluids cavitation pressure using a mechanical tester and a closed syringe. Elongational properties are obtained with a falling bob technique. Fluid rheology has a strong influence on filamentation. The cavitation results do not give a direct correlation with filament volume. The elongational properties of the fluids have a strong effect on filamentation but in a complex manner. As printing speed or ink film thickness increases, the filaments increase in average size and in their size distribution. The nip loading does not have a large effect on filament size nor the size distribution. Porous substrates reduces or eliminates the “remains” within the detectable limit. An empirical correlation is developed to link average filament volume to dimensionless parameters of Reynolds number, Deborah number, and Trouton’s ratio. Reasonable correlations are obtained for specific groups of fluids but low correlation is found for the entire fluid set. A physical model is proposed to predict the occurrence of filamentation and the filament volume. Theoretical predictions are compared to the experimental filament volume for all fluids. The results indicate that a small number of cavities that are formed actually coalesce to form filaments. By altering this fraction linearly with the Trouton ratio, the filament volumes are predicted. The Newtonian model including the elongational effects predicts the filament volume best. The persistent wide scatter in the results compared to the model or the empirical correlation implies that at least one other parameter affects the filamentation process

The effect of probiotic tablet usage on the clinical, microbiological and biochemical parameters in smokers and nonsmokers individuals with gingivitis: A randomized placebo-controlled clinical trial

YÖK Tez ID: 443910Sigaranın periodontal tedavi yanıtını olumsuz etkilediği bilinmekte ve bu etkisini engelleyecek yaklaşımlar araştırılmaktadır. Probiyotiklerin, kommensal florayı artırarak ve periodontopatojenlerin kolonizasyonunu önleyerek gingival enflamasyon ile ilişkili mikrobiyolojik geçişi engellediği düşünülmektedir. Sigara içen gingivitisli bireylerde probiyotik kullanımının periodontal durumu olumlu yönde etkileyeceği düşünülebilir. Bu çalışmanın amacı, sigara içen ve içmeyen, gingivitisli bireylerde probiyotik tablet kullanımının klinik, mikrobiyolojik ve enflamatuvar belirteçler üzerine etkisini araştırmaktır. Bu çalışma randomize, çift kör, plasebo kontrollü klinik çalışma olarak planlanmıştır. Gingivitisli 80 hasta sigara içme durumlarına göre sınıflandırıldıktan sonra (40 sigara içen (+), 40 sigara içmeyen ( -)) her iki grup randomize olarak plasebo (K) veya probiyotik tablet (T) gruplarına dağıtılmıştır. Her bireye 30 gün boyunca günde bir kere bulundukları gruplara göre 1 adet plasebo veya test tablet i verilmiştir. Tüm hastalara deney periyodundan önce polisaj (lastik fırça ve abraziv pat) ve diş yüzey temizliğini içeren mekanik debridman yapılmıştır. Tüm bireylerden plak ve gingival indeksleri içeren klinik parametreler ve dişeti oluğu sıvısı (DOS) / subgingival plak örnekleri 0. (başlangıç), 30. (1. ay) ve 60. (2. ay) günlerde elde edilmiştir. DOS'ndaki interlökin (IL)-6, IL-8 ve IL-10 seviyelerine enzim bağlı immunosorbent analiz (ELISA) ile bakılmıştır. Subgingival plak örnekleri kantitatif gerçek zamanlı polimeraz zincir reaksiyonu (kGZ-PZR) ile analiz edilmiştir. Klinik, biyokimyasal ve mikrobiyolojik sonuç değişkenleri gruplar arası ve grup içinde kıyaslanmıştır. Başlangıçta sadece gingival indeksin (Gİ) sigara içen gruplarda (+) içmeyenlere (-) göre daha düşük olduğu görülmüştür (p<0.05). Tüm gruplardaki tüm klinik ve biyokimyasal parametrelerin istatistiksel olarak anlamlı şekilde zamana bağlı azaldığı gösterilmiştir (p<0.05). Fakat test gruplarında, kontrol gruplarına göre DOS hacmi ve DOS IL-6, IL-8 ve IL-10 seviyeleri açısından daha iyi sonuçlar elde edilmiştir. Plak indeksi (Pİ), K(+) grubunda T(-) grubuna kıyasla ve K(-) grubunun Gİ'i, T(+) grubuna göre 1. ayda daha yüksek izlenmiştir (p<0.05). DOS hacmi xi açısından gruplar arası herhangi bir zaman aralığında bir fark izlenmezken, Pİ'i sigara içen gruplarda içmeyenlere göre 2. ayda daha yüksek izlenmiştir (p<0.05). K( -) grubundaki DOS IL-8 seviyeleri ve her iki kontrol grubundaki IL-6, T(+) grubuna göre ve kontrol gruplarındaki IL-10 seviyeleri T(-) grubuna göre 2. aylık takipte istatistiksel olarak anlamlı şekilde daha yüksek izlenmiştir (p<0.05). Mikrobiyolojik değişkenler açısından grup içi ve gruplar arası anlamlı bir değişiklik olmadığı görülmüştür. Sonuç olarak, yardımcı tedavi olarak probiyotik tabletlerin kullanımı sigara durumundan bağımsız olarak plasebo gruplarına kıyasla DOS hacmi ve IL-6, IL-8 ve IL-10 seviyeleri açısından terapötik sonuçları geliştirdiği ve sigara içen ve içmeyen gingivitisli bireylerde subklinik bir yarar sağladığı görülmüştür. En iyi sonuçlar kontrol gruplarına kıyasla her iki test grubunda elde edilmiş olmasına rağmen, sigara içen ve içmeyen gruplar arasında bir farka rastlanmamıştır.The negative effects of smoking on periodontal therapy were well known and many approaches were investigated to prevent of its effect. The use of probiotics have been proposed, based on their mechanism of action of enhancing the commensal flora and preventing the colonization of true pathogens, and thus, preventing the microbiological shifts associated with gingival inflammation. It can be hypothesized that the use of probiotics in smoker patients with gingivitis can be considered to have a positive effect on periodontal status. The aim of this study is to evaluate the efficacy of oral administration of probiotic tablets on the clinical, microbiological parameters and the levels of selected inflammatory mediators in gingival crevicular fluid (GCF) in smokers and nonsmokers with gingivitis. This study designed as a double-blind randomized placebo-controlled clinical trial. Eighty patients with gingivitis, were following stratification for smoking (40 smokers (+), 40 non-smokers (-)), randomly assigned to two groups to receive probiotic (T) or placebo (C) tablets. Each subject was instructed to chew one tablet per day, during 30 days. All patients received mechanical debridement procedure including tooth-polishing (rubber cup and abrasive paste) and scaling before the experimental period. Clinical parameters including plaque and gingival indices and GCF/subgingival plaque samples obtained from all subjects on days 0 (baseline), 30 (1. ay), and 60 (2. ay). The GCF levels of interleukin (IL)-6, IL-8 and IL-10 determined using enzyme-linked immunosorbent assay (ELISA). Subgingival samples were analysed by quantitative real-time polymerase chain reaction (qRT PCR). Clinical, biochemical and microbiological outcome variables were compared between and within groups. At baseline only gingival index (GI) was significantly lower in both smoker groups (+) than non-smokers (-) (p<0.05). Statistical analyses demonstrated xiii significant time-dependent reduction with treatment compared to baseline in all clinical and biochemical parameters for all groups (p<0.05). But more favourable results were obtained for GCF volume and GCF levels of IL-6, IL-8 and IL-10 generally in test groups than control groups. Plaque index (PI) was significantly higher at C(+) compared to T(-) group and GI of C(-) group was higher than the T(+) group at 1 month (p<0.05). GCF volume did not show significantly intergroup difference at any time interval whereas PI was significantly higher in both smoker groups compared with the non-smoker groups in 2-month follow-up (p<0.05). GCF levels of IL-8 in C(-) group, IL-6 in both control groups were significantly higher compared to T(+) group and IL-10 in both control groups were significantly higher compared to T(-) group at 2 month follow up (p<0.05). There were no significant changes between and within the groups in the microbiological variables. In conclusion, adjunctive probiotic tablets enhances therapeutic outcomes regardless of smoking compared with placebo according to the GCF volume and levels of IL-6, IL-8 and IL-10 variables, resulting in subclinic benefit in both smokers and non-smokers with gingivitis. Although more favourable results were obtained in both test groups compared to control groups, there were no differences among the smokers and non-smokers for both test and control groups

Sigara içen ve içmeyen gingivitisli bireylerde probiyotik tablet kullanımının klinik, mikrobiyolojik ve biyokimyasal parametreler üzerine etkisi : randomize-plasebo kontrollü klinik çalışma

Tez (Doktora) -- Kırıkkale Üniversitesi111019

An econometric analysis of the current account deficit in Turkish Economy

The world economy maintained its high rated growth in 2006. While China continued to become the main determinant of the ongoing strong growth tendency of the world economy, stable growth in the economies of the European Union and Japan contributed to the growth in the world economy. Uncertainties about oil prices and international liquidity conditions and global in stabilities, such as current account deficits are the lea ding risks for growth of the world economy. Current account deficits have been seen developed and developing countries. IMF estimates that curr ent account deficits will continue in U.S and in some emerging countries. In Turkey, current account deficit exceeded 8 percent of GDP in 2006, as well. The main goal of this paper is to provide general framework about current account balance and analyze the dynamics of current account deficit in Turkey by using time series econometric techniques

Design of a blended learning environment: Considerations and implementation issues

This study identified critical issues in the design of a blended learning environment by examining basic design considerations and implementation issues. Following a design-based research approach with the phenomenological tradition of qualitative research, the study investigated instructor experiences relating to the design, development, and implementation processes of a blended course. The results reveal that the design considerations centred on the pedagogical approach, course organization, materials preparation, interactions, and the instructor's and students' roles. The affordances of the implementation included the arousal of the students' interest and participation, flexibility, time conservation, the ability to track student progress, and the improvement of interaction, collaboration, and communication opportunities. The challenges were increased workload, course and time management, overlaps, and the creation of harmony between the face-to-face and online environments. The overall results show that the critical issues involved context, the pedagogical framework, instructor competency, and technical issues in the blended course design

The effect of synbiotic tablet usage on the clinical and biochemical parameters in smokers and nonsmokers with gingivitis: a randomized placebo-controlled clinical trial

Introduction The aim of this study is to evaluate the efficacy of oral administration of synbiotic tablets on the clinical parameters and the levels of selected inflammatory mediators in gingival crevicular fluid (GCF) in smokers and non-smokers with gingivitis. Methods Eighty patients with gingivitis (40 smoker (+), 40 non-smoker (-)), randomly assigned to test (T) or control (C) groups. Each subject was instructed to chew one tablet per day, during 30 days. Clinical parameters including plaque and gingival indices and GCF samples obtained from all subjects on baseline, 1st month, and 2nd month. The GCF levels of interleukin (IL)-6, IL-8 and IL-10 were determined. Results All clinical and biochemical parameters for all groups were significantly reduced compared to baseline (p<0.05). GCF volume didn’t show a significant intergroup difference at any time whereas Plaque Index (PI) was significantly higher in both smoker groups compared with the T(-) group in the 2nd month follow-up (p<0.05). GCF levels of IL-8 in C(-) group, IL-6 in both control groups were significantly higher compared to T(+) group and IL-10 in both control groups were significantly higher compared to T(-) group at the 2nd month follow up (p<0.05). Conclusions Adjunctive synbiotic tablets enhance subclinic therapeutic outcomes regardless of smoking compared with placebo according to the levels of IL-6, IL-8 and IL-10 variables

Contrast-enhanced MR angiography of thoracic vascular malformations in children

To plan an effective management of thoracic vascular malformations, clinicians must have a clear understanding of the anatomy. Although echocardiography and angiography are the leading imaging modalities in patients with congenital cardiovascular anomalies, magnetic resonance (MR) imaging and computed tomography (CT) are valuable noninvasive adjuncts. MR imaging and CT are effective in demonstrating the complex extracardiac morphology and yield helpful information that can change the treatment plan. Although recent reports state the usefulness of multidetector CT (MDCT), in terms of pediatric population, the significance of radiation exposure should be taken into account. Thus, contrast enhanced MR angiography, as a guide in planning surgery, seems to be the best alternative to conventional angiography in the diagnosis of congenital vascular malformations. In this review, the diagnostic features of thoracic vascular malformations in pediatric population are discussed, and, the potential uses of contrast-enhanced MR angiography are emphasized with the retrospective evaluation of imaging findings in 114 examinations