Extraction of Saponins from Soapnut (Sapindus Mukorossi) and Their Antimicrobial Properties

In this study optimization of extraction conditions for saponin from Sapindus mukorossi was investigated. Results showed that polarity of the extraction solvent affects the yield percentage of the extraction process. Best yield percentage was obtained as 78.1 % at 1:10 solid-liquid ratio in aqueous ethanol solution (50% v/v). The antimicrobial properties of extracts containing saponins were investigated for different microorganisms. Minimum inhibition concentrations of extract were obtained against Escherichia coli, Staphylococcus aureus and Candida albicans. Minimum inhibition concentrations (MIC) of saponin extract ranged between 12.5 mg/mL to 25 mg/mL.nbs

Evaluation of nutritional status in pediatric intensive care unit patients: the results of a multicenter, prospective study in Turkey

IntroductionMalnutrition is defined as a pathological condition arising from deficient or imbalanced intake of nutritional elements. Factors such as increasing metabolic demands during the disease course in the hospitalized patients and inadequate calorie intake increase the risk of malnutrition. The aim of the present study is to evaluate nutritional status of patients admitted to pediatric intensive care units (PICU) in Turkey, examine the effect of nutrition on the treatment process and draw attention to the need for regulating nutritional support of patients while continuing existing therapies.Material and MethodIn this prospective multicenter study, the data was collected over a period of one month from PICUs participating in the PICU Nutrition Study Group in Turkey. Anthropometric data of the patients, calorie intake, 90-day mortality, need for mechanical ventilation, length of hospital stay and length of stay in intensive care unit were recorded and the relationship between these parameters was examined.ResultsOf the 614 patients included in the study, malnutrition was detected in 45.4% of the patients. Enteral feeding was initiated in 40.6% (n = 249) of the patients at day one upon admission to the intensive care unit. In the first 48 h, 86.82% (n = 533) of the patients achieved the target calorie intake, and 81.65% (n = 307) of the 376 patients remaining in the intensive care unit achieved the target calorie intake at the end of one week. The risk of mortality decreased with increasing upper mid-arm circumference and triceps skin fold thickness Z-score (OR = 0.871/0.894; p = 0.027/0.024). The risk of mortality was 2.723 times higher in patients who did not achieve the target calorie intake at first 48 h (p = 0.006) and the risk was 3.829 times higher in patients who did not achieve the target calorie intake at the end of one week (p = 0.001). The risk of mortality decreased with increasing triceps skin fold thickness Z-score (OR = 0.894; p = 0.024).ConclusionTimely and appropriate nutritional support in critically ill patients favorably affects the clinical course. The results of the present study suggest that mortality rate is higher in patients who fail to achieve the target calorie intake at first 48 h and day seven of admission to the intensive care unit. The risk of mortality decreases with increasing triceps skin fold thickness Z-score

Effect of pretreatment on the performance of metal contaminated commercial FCC catalyst

The performance of fluid catalytic cracking (FCC) catalyst decreases due to the severe negative effects of metal contaminants (e.g., nickel, vanadium and iron) deposited on the catalyst from the hydrocarbon feed. The metal contaminants cause an increase in the production of gas and coke at the expense of gasoline.;In this work the effect of pretreatment with hydrogen and methane gases on the performance of commercial, metal-contaminated, FCC equilibrium catalysts was investigated. Cracking reactions of both sour imported heavy gas oil (SIHGO) and n-hexadecane were carried out in a microactivity test (MAT) unit using three commercial equilibrium catalysts with different metals concentrations. These catalysts were also characterized by temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), surface area measurements (BET/T-Plot), atomic force microscopy (AFM), and scanning electron microscopy in combination of elemental analysis by EDX (SEM-EDX). The characterization data were used in the interpretation of the MAT results.;MAT results have shown that pretreatment of catalysts with hydrogen and methane prior to cracking reactions decreases the yields of hydrogen and coke from gas oil cracking with a significant increase in gasoline yield. The decrease in hydrogen and coke yields with pretreatment was attributed to the lower dehydrogenation activity of reduced vanadium compared to oxidized vanadium.;In TPR spectrum the metal oxide represented by the peak at around 690°C was found to be active in dehydrogenation during cracking reactions. TPO experiments were carried out to determine the nature, and composition of the coke on the spent catalysts. TPO profiles were deconvoluted into four peaks (Peak K, L, M and N). The location of TPO peaks shifted to lower temperatures with increasing metal concentrations due to the catalytic effects of metals on the oxidation reaction. Peak L was assigned to the contaminant coke in the vicinity of metals. Surface area measurements indicated that the coke preferentially deposits in the micropores of the catalyst. AFM images have shown that roughness of surface decreased with increasing metal concentrations on the catalyst. These images also revealed the presence of debris on the catalyst surface. Iron was detected in some of these debris using SEM-EDX analysis

Essays on Education Market Design

This thesis consists of two essays on education market design. Chapter 1, “Education Market in the Presence of Peer Effects: Theory and Evidence From South Korea” is a joint work with Sam Il Myoung Hwang. In this paper we evaluate alternative market designs in the presence of peer effect considerations in school choice. Schools can differentiate by peer composition among other characteristics. Different rules public schools are subject to compared to elite or private schools have been heavily debated because of their effects on student distribution. In many countries former group admit students earlier than the latter, which we call Sequential Admissions (SA). Furthermore, the former group can use academic criteria in admissions unlike the latter. We study the effect of these admission aspects on welfare and distribution. Our analysis has important distinguishing features. First, it includes private schools as well as public schools, whereas previous studies on admission rules focused on centralized public school allocation. Second, students can have preferences for peer composition at schools. This is an important factor that can determine sorting behavior which is not carefully studied before. First we theoretically study equilibria of the admission games complicated by the peer effects. Then we estimate a structural model using detailed high school applications data from Seoul to run counterfactual simulations. We show that SA can approximate centralized admission schemes well. This is important since complete centralization is known to increase welfare but hard to implement in many cases. Moreover analysis of SA is informative on the controversial “exploding offers” in labor markets. Regarding admission criteria, we show that use of academic criteria in a subset of schools increases the desirability of these schools. The reason is that high performing students want to coordinate to study together and academic screening provides this. This suggest that, school choice is also a coordination game, not just an object allocation problem. Chapter 2, “The Role of Outside Options under Boston Mechanism” studies ex ante welfare from centralized public school allocation for students who cannot go to private schools when there are others who have such option. I show that when a private school is preferred to only the last option, students prefer Boston Mechanism (BM) to Deferred Acceptance (DA). Analyzing the case of desirable private schools in a model with three public schools, I demonstrate that students who are marginal in the decision of which school to report as top choice are better off under DA compared to BM; whereas inframarginal students are better off under BM. I show that a distribution of preferences with full support guarantees the existence of students who are better off under BM compared to DA. Assuming uniform distribution of preferences allows one to find the fraction of students who are better off under BM compared to DA. Analysis of the effect of private school entry on the welfare of students who cannot access private schools demonstrates that under mild conditions either there are students who are strictly better off after the entry or welfare of none of the students change

Silk Fibroin Nanofibers Loaded with Hydroxytyrosol from Hydrolysis of Oleuropein in Olive Leaf Extract

The purpose of this study was to prepare antimicrobial silk fibroin nanofibers from the aqueous formic acid solutions of silk fibroin and hydroxytyrosol with the in situ hydrolysis of oleouropein present in olive leaf extract using electrospinning method. With the use of aqueous formic acid solution of olive leaf extract and silk fibroin resulted in more uniform and beadless nanofibers. Morphological properties of electrospun nanofibers were investigated using Scanning Electron Microscope (SEM). The diameter of electrospun nanofibers ranged between 70 nm to 150 nm. The nanofiber diameter did not changed much with increasing concentration of olive leaf extract added into silk fibroin solution to be used in electrospinning process. The increase in olive leaf extract concentration resulted in beadless and uniform nanofiber structures. The average diameter of the nanofibers prepared with fibroin solution having 10 % olive leaf extract was determined as 85 ± 10 nm. Results revealing the formation of smoother and uniform nanofibers was attributed to the crosslinking effect of oleuropein and polyphenols present in olive leaf extract with certain functional groups in silk fibroin structure. Antibacterial properties of hydroxytyrosol loaded nanofibers against Staphylococcus epidermidis (Gram +) and Escherichia coli (Gram -) were confirmed with the clear inhibition zones observed in disc diffusion tests. Silk Fibroin nanofibers loaded with hydroxytyrosol may offer a new alternative biomaterial to be used in wound dressing or medical textile applications

Use of ozone for the preparation of functional silk fibroin-based biomaterial loaded with bioactive compounds for biomedical applications

###EgeUn###Silk fibroin (SF) can be used for the preparation of porous functional biomaterials due to its biocompatibility, biodegradability, and minimal inFLammatory reactions. High porosity and homogenous interconnected pore structure is a challenge for the preparation of porous biomaterials. Porous SF foam materials can be formed by bubbling inert gases through aqueous solutions and subsequent freeze drying process. In this study, SF foam structures were prepared by first purging ozone gas and then freeze drying of this ozone-treated aqueous SF solution. Resulting porous materials were efficiently loaded with plant extract for the preparation of functional biomaterials having antimicrobial properties. The interactions of SF with ozone led to chemical modifications that improved both foaming and hydrophobic properties. Intensive ozone treatment caused the crystallinity degree of untreated SF to decrease from 48% to 42%. Ozone treatment also resulted in a significant reduction in surface tyrosine content from 55% to 43%. The use of ozone gas for the preparation of SF foam material enhanced the adsorption capacity of phenolic compounds. The enhancement in the adsorption of phenolic compounds on SF foam structure can be attributed to the oxidation-dependent increase in hydrophobicity

ADSORPTION/DESORPTION AND BIOFUNCTIONAL PROPERTIES OF OLEUROPEIN LOADED ON DIFFERENT TYPES OF SILK FIBROIN MATRICES

WOS: 000405119400013The objective of this study was to investigate the adsorption/desorption behavior of oleuropein on different types of silk fibroin matrices including silk fibroin microfibers (MF), regenerated silk fibroin (RSF), and silk fibroin nanofibers (NF). Nanofibers with an average diameter of ranging between 24 and 326 nm were successfully prepared using the electrospinning technique. The effects of the silk fibroin concentration, the voltage applied and the distance between needle tip and collector plate on the morphology of the NF were investigated. The adsorption capacities of MF, RSF and NF were determined as 104.92, 163.07 and 228.34 mg oleuropein per gram of material, respectively. The percentage of initially adsorbed oleuropein that was desorbed was 86.08, 91.29 and 96.67% for MF, RSF and NF, respectively. NF and RSF discs loaded with oleuropein were subjected to disc diffusion assays to determine their antibacterial activity against test microorganisms Staphylococcus epidermidis (Gram +) and Escherichia coli (Gram -). The results showed that both biomaterials possessed antibacterial properties after loading with oleuropein. Wound scratch assays using oleuropein released from NF revealed an enhancement of cell migration, indicating a wound healing property of the material. In conclusion, the NF can be utilized as a biofunctional polymeric material with better performance for the adsorption and desorption of oleuropein compared with MF and RSF.Natural Products Research Development Unit (NPRDU) located in Technology Development Zone [DUA01/2010]The support (DUA01/2010) from Natural Products Research Development Unit (NPRDU) located in Technology Development Zone for the thesis study of Mr. Ali Bora Balta is gratefully acknowledged

Development and Characterization of Silk Fibroin-based Oral Films Containing Turmeric Extract as Dietary Supplement

Dietary supplements have extreme importance. Due to the easily degradable nature of these supplements, the development and application of carrier systems in food technologies seem to be extremely important. Today, oral film technologies have gained importance due to their rapid and high absorption properties. This study chose silk fibroin (SF) as the main component due to its high biocompatibility. Turmeric extract has been added to the oral films as an active agent. The prepared films were analyzed with atomic force microscopy (AFM) and scanning electron microscopy (SEM) to reveal their morphological properties, and at the same time, the film thickness was measured. It has been found that the increase in extract amount is a factor that causes an increase in film roughness while causing a decrease in phase separation. It was observed that the film roughness increased twice with the addition of extract. The roughness of the films formed with 15% extract was measured as 28.5. The average roughness of the films formed without the use of extracts was observed as 15.7 mm. It was also observed that the Trolox equivalent antioxidant capacity (TEAC) was doubled for films containing 15% turmeric extract after one hour of release. The films exhibited different weight loss profiles after release as the amount of turmeric extract was changed. Disc diffusion experiments revealed that films containing turmeric extract exhibited antimicrobial effects

Encapsulation of lycopene using electrospraying method

WOS: 000387337100014In this study encapsulation of lycopene with zein as a biopolymer by using electrospraying method to enhance stability of lycopene was carried out. Effect of the encapsulation on the lycopene stability was investigated after exposure to UV light. The results were compared and discussed in terms of morphology and effectiveness of the encapsulation system for enhanced stability of lycopene. The results showed that encapsulation of lycopene using zein as biopolymer improved the stability of lycopene