A digital microfluidic interface between solid-phase microextraction and liquid chromatography-mass spectrometry

Choi, K.,Boyaci, E.,Kim, J.,Seale, B.,Barrera-Arbelaez, L.,Pawliszyn, J.,Wheeler, A.R. Elsevier 2016 Journal of chromatography Vol.1444 No.-

<P>We introduce a method to couple solid-phase microextraction (SPME) with HPLC-MS using digital microfluidics (DMF). In the new system, SPME fibers are used to extract analytes from complex sample solutions, after which the analytes are desorbed into solvent droplets in a DMF device. The open geometry of DMF allows straightforward insertion of SPME fibers without requiring a complicated interface, and automated droplet manipulation enables multiplexed processing of the fibers. In contrast to other multiplexed SPME elution interfaces, the low volumes inherent to DMF allow for pre-concentration of analytes prior to analysis. The new SPME-DMF-HPLC-MS method was applied to the quantification of pg/mL-level free steroid hormones in urine. We propose that this new method will be useful for a wide range of applications requiring cleanup and pre-concentration with convenient coupling to high-performance analytical techniques. (C) 2016 Elsevier B.V. All rights reserved.</P>

Nonlinear vibrations of axially moving beams with multiple concentrated masses Part I: primary resonance

Sarigul, M.,Boyaci, H. Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.36 No.2

Transverse vibrations of axially moving beams with multiple concentrated masses have been investigated. It is assumed that the beam is of Euler-Bernoulli type, and both ends of it have simply supports. Concentrated masses are equally distributed on the beam. This system is formulated mathematically and then sought to find out approximately solutions of the problem. Method of multiple scales has been used. It is assumed that axial velocity of the beam is harmonically varying around a mean-constant velocity. In case of primary resonance, an analytical solution is derived. Then, the effects of both magnitude and number of the concentrated masses on nonlinear vibrations are investigated numerically in detail.

Nonlinear vibrations of axially moving beams with multiple concentrated masses Part I: primary resonance

M. Sar gül,H. Boyaci 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.36 No.2

Transverse vibrations of axially moving beams with multiple concentrated masses have been investigated. It is assumed that the beam is of Euler-Bernoulli type, and both ends of it have simply supports. Concentrated masses are equally distributed on the beam. This system is formulated mathematically and then sought to find out approximately solutions of the problem. Method of multiple scales has been used. It is assumed that axial velocity of the beam is harmonically varying around a mean-constant velocity. In case of primary resonance, an analytical solution is derived. Then, the effects of both magnitude and number of the concentrated masses on nonlinear vibrations are investigated numerically in detail.

Evaluation of long- and short-term storage conditions and efficiency of a novel microencapsulated Salmonella phage cocktail for controlling Salmonella in chicken meat

Banu Sezer,Ismail Hakki Boyaci 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.2

This study aims to assess the stability and activity of using a lyophilization, formulation design and to evaluate their efficiency for controlling Salmonella in chicken meat. The phage-loaded 0.3 M sucrose gelatin mixture at 4 and 25 °C displayed significantly less phage titer loss (p < 0.05) than the other excipients and liquid phage cocktail in 12 months. The results showed that there were significant reductions of Salmonella at the end of the storage in chicken meat for newly prepared phage powder (1.86 log CFU/cm2 and 2.18 log CFU/cm2), lyophilized phage powders stored at 4 °C (1.08 log CFU/cm2 and 1.26 log CFU/cm2) and stored at 25 °C (0.66 log CFU/cm2 and 1.00 log CFU/cm2) for 10 months at MOI 100 and 1000, respectively. The results demonstrated that lyophilized phages in a simple food grade formulation can be successfully stored and might be used in biocontrol of Salmonella in meat.

The effects of incorporating oleogel on properties of model system emulsions

Sila Ҫalişkan,Özlem Yüncü-Boyaci,Meltem Serdaroğlu 한국축산식품학회 2024 Food and Life Vol.2024 No.2

This study aimed to emphasize the utilization of oleogel containing chitosan and pomegranate seed oil as a replacer for beef fat in model system meat emulsions (MEs). For this purpose, beef fat was replaced with oleogel at levels of 0% (C), 50% (OG50), 75% (OG75), and 100% (OG100). The chemical composition, technological quality, microstructure, and oxidative changes of the MEs were investigated. The incorporation of oleogel in MEs effectively reduced saturated fatty acids and cholesterol levels while showing significant increases in polyunsaturated fatty acids. Additionally, the re-formulation process exhibited promising outcomes in enhancing n-3 content. On the other hand, replacing beef fat with more than 50% oleogel led to a decrease in the emulsion stabilities of the MEs. Despite causing changes in color and texture, the inclusion of oleogel proved effective in enhancing oxidative stability. The highest 2-thiobarbituric acid re-active substances (TBAR) value was found in control treatment throughout storage. Furthermore, scanned electron mi-croscope images of the products exhibited a more organized structure in reformulated samples. The comprehensive findings indicate that integrating oleogels into ME formulations can effectively contribute to achieving a healthier lipid profile, along with favorable textural, nutritional, and oxidative qualities.

Determination of yolk:white ratio of egg using SDS-PAGE

Reyhan Selin Uysal,Esra Acar-Soykut,Ismail Hakki Boyaci 한국식품과학회 2020 Food Science and Biotechnology Vol.29 No.2

The aim of present study was to determine liquid egg adulteration based on yolk:white ratio of egg using sodium dodecyl sulphate-polyacrylamide gel electrophoresis and by measuring Brix. To construct a calibration model, liquid egg samples were prepared by mixing egg yolk and white (yolk:white) at different concentrations. A high coefficient of determination value (R2 = 0.992) was obtained. Limit of detection and limit of quantification were estimated as 62 g/kg and 187 g/kg. The accuracy of the model was tested using eleven LWE samples, and the yolk ratios of 90.9% of these samples were predicted successfully. Liquid whole egg (LWE) containing additional egg white up to 30% was also predicted with a low relative error of less than 10%. Yolk:white ratio of LWE samples and authentication of the components of LWE (containing extra white or water) can be determined using proposed method.

Mineral content analysis of root canal dentin using laser-induced breakdown spectroscopy

Eren, Selen Kucukkaya,Uzunoglu, Emel,Sezer, Banu,Yilmaz, Zeliha,Boyaci, Ismail Hakki The Korean Academy of Conservative Dentistry 2018 Restorative Dentistry & Endodontics Vol.43 No.1

Objectives: This study aimed to introduce the use of laser-induced breakdown spectroscopy (LIBS) for evaluation of the mineral content of root canal dentin, and to assess whether a correlation exists between LIBS and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) methods by comparing the effects of irrigation solutions on the mineral content change of root canal dentin. Materials and Methods: Forty teeth with a single root canal were decoronated and longitudinally sectioned to expose the canals. The root halves were divided into 4 groups (n = 10) according to the solution applied: group NaOCl, 5.25% sodium hypochlorite (NaOCl) for 1 hour; group EDTA, 17% ethylenediaminetetraacetic acid (EDTA) for 2 minutes; group NaOCl+EDTA, 5.25% NaOCl for 1 hour and 17% EDTA for 2 minutes; a control group. Each root half belonging to the same root was evaluated for mineral content with either LIBS or SEM/EDS methods. The data were analyzed statistically. Results: In groups NaOCl and NaOCl+EDTA, the calcium (Ca)/phosphorus (P) ratio decreased while the sodium (Na) level increased compared with the other groups (p < 0.05). The magnesium (Mg) level changes were not significant among the groups. A significant positive correlation was found between the results of LIBS and SEM/EDS analyses (r = 0.84, p < 0.001). Conclusions: Treatment with NaOCl for 1 hour altered the mineral content of dentin, while EDTA application for 2 minutes had no effect on the elemental composition. The LIBS method proved to be reliable while providing data for the elemental composition of root canal dentin.

Inflammatory biomarkers may predict response to phosphodiesterase type 5 inhibitor treatment in patients with erectile dysfunction

Metin Kilic,Anil Erkan,Salim Zengin,Gokce Dundar,Caglar Boyaci 대한비뇨의학회 2023 Investigative and Clinical Urology Vol.64 No.4

Purpose: In this study, we aimed to evaluate the clinical utility of the neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), lymphocyte/monocyte ratio (LMR), and monocyte/high-density lipoprotein cholesterol ratio (MHR) in predicting response to a phosphodiesterase type 5 inhibitor (PDE5i) when used as the first-line medical treatment of erectile dysfunction (ED). Materials and Methods: This study prospectively included 185 patients who were diagnosed with ED and started PDE5i treatment. After PDE5i treatment, 107 (57.8%) patients with an International Index of Erectile Function-5 (IIEF-5) score below 22 were assigned to Group 1, and 78 (42.2%) patients with an IIEF-5 score of 22 or above were assigned to Group 2. The outcome measures of the study were demographic characteristics and inflammation markers between the groups. Results: The mean IIEF-5 change after PDE5i treatment was 6.1±4.2 points in Group 1 and 11.5±3.2 points in Group 2 (p=0.001). The mean age was 54.6±9.2 years in Group 1 and 47.8±10.3 years in Group 2 (p<0.001), and the median fasting blood glucose values of Groups 1 and 2 were 105 (36) mg/dL and 97 (23) mg/dL, respectively (p=0.010). The LMR and MHR values were 2.39±0.23 and 13.8±7, respectively, for Group 1, and 2.03±0.22 and 17±6.6, respectively, for Group 2 (p=0.044 and p=0.002, respectively). On multivariable analysis, younger age and increased MHR were independent predictors of benefit from PDE5i treatment. Conclusions: This study showed that only MHR as an inflammatory biomarker was an independent predictor for response to PDE5i in the treatment of ED. Also, several factors were predictive of treatment failure.