32 results on '"Deniz Türkmen"'
Search Results
2. Development of Molecularly Imprinted Magnetic Amino Acid-Based Nanoparticles for Voltammetric Analysis of Lead Ions in Honey
- Author
-
Mehmet Karagözlü, Süleyman Aşır, Nemah Abu Shama, Ilgım Göktürk, Fatma Yılmaz, Deniz Türkmen, Adil Denizli, and Murat Özgören
- Subjects
lead ,imprinted polymer ,magnetic nanoparticles ,carbon paste electrode ,electrochemical biosensor ,differential pulse voltammetry ,Organic chemistry ,QD241-441 - Abstract
Lead (Pb) is a hazardous metal that poses a significant threat to both the environment and human health. The presence of Pb in food products such as honey can pose a significant risk to human health and is therefore important to detect and monitor. In this study, we propose a voltammetric detection method using molecularly imprinted polymer (MIP) electrodes to detect Pb (II) ions in honey. Pb (II) ion-imprinted amino acid-based nanoparticles with magnetic properties on a carbon paste electrode (MIP-CPE) were designed to have high sensitivity and selectivity towards Pb (II) ions in the honey sample. Zetasizer measurements, electron spin resonance, and scanning electron microscopy were used to characterize magnetic polymeric nanoparticles. The results showed that the voltammetric detection method using MIP-CPE was able to accurately detect Pb (II) ions in honey samples with a low detection limit. The proposed method offers a simple, rapid, cost-effective solution for detecting Pb (II) ions in honey. It could potentially be applied to other food products to ensure their safety for human consumption. The MIP-CPE sensor was designed to have high sensitivity and selectivity towards Pb (II) ions in the honey sample. The results showed that the technique was able to deliver highly sensitive results since seven different concentrations were prepared and detected to obtain an R2 of 0.9954, in addition to a low detection limit (LOD) of 0.0912 µM and a low quantification limit (LOQ) of 0.276 µM. Importantly, the analysis revealed no trace of Pb (II) ions in the honey samples obtained from Cyprus.
- Published
- 2024
- Full Text
- View/download PDF
3. SLCO1B1 Exome Sequencing and Statin Treatment Response in 64,000 UK Biobank Patients
- Author
-
Deniz Türkmen, Jack Bowden, Jane A. H. Masoli, David Melzer, and Luke C. Pilling
- Subjects
cholesterol ,statin ,SLCO1B1 ,clinical response ,pharmacogenomics ,exome sequencing variants ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
The solute carrier organic anion transporter family member 1B1 (SLCO1B1) encodes the organic anion-transporting polypeptide 1B1 (OATP1B1 protein) that transports statins to liver cells. Common genetic variants in SLCO1B1, such as *5, cause altered systemic exposure to statins and therefore affect statin outcomes, with potential pharmacogenetic applications; yet, evidence is inconclusive. We studied common and rare SLCO1B1 variants in up to 64,000 patients from UK Biobank prescribed simvastatin or atorvastatin, combining whole-exome sequencing data with up to 25-year routine clinical records. We studied 51 predicted gain/loss-of-function variants affecting OATP1B1. Both SLCO1B1*5 alone and the SLCO1B1*15 haplotype increased LDL during treatment (beta*5 = 0.08 mmol/L, p = 6 × 10−8; beta*15 = 0.03 mmol/L, p = 3 × 10−4), as did the likelihood of discontinuing statin prescriptions (hazard ratio*5 = 1.12, p = 0.04; HR*15 = 1.05, p = 0.04). SLCO1B1*15 and SLCO1B1*20 increased the risk of General Practice (GP)-diagnosed muscle symptoms (HR*15 = 1.22, p = 0.003; HR*20 = 1.25, p = 0.01). We estimated that genotype-guided prescribing could potentially prevent 18% and 10% of GP-diagnosed muscle symptoms experienced by statin patients, with *15 and *20, respectively. The remaining common variants were not individually significant. Rare variants in SLCO1B1 increased LDL in statin users by up to 1.05 mmol/L, but replication is needed. We conclude that genotype-guided treatment could reduce GP-diagnosed muscle symptoms in statin patients; incorporating further SLCO1B1 variants into clinical prediction scores could improve LDL control and decrease adverse events, including discontinuation.
- Published
- 2024
- Full Text
- View/download PDF
4. Development of a Plasmonic Sensor for a Chemotherapeutic Agent Cabazitaxel
- Author
-
Süleyman Aşır, Buse Uğur, Mitra Jalilzadeh, Ilgım Göktürk, and Deniz Türkmen
- Subjects
Chemistry ,QD1-999 - Published
- 2022
- Full Text
- View/download PDF
5. Inspirations of Biomimetic Affinity Ligands: A Review
- Author
-
Aykut Arif Topçu, Seçkin Kılıç, Erdoğan Özgür, Deniz Türkmen, and Adil Denizli
- Subjects
Chemistry ,QD1-999 - Published
- 2022
- Full Text
- View/download PDF
6. Computational Investigation of the Monomer Ratio and Solvent Environment for the Complex Formed between Sulfamethoxazole and Functional Monomer Methacrylic Acid
- Author
-
Sisem Ektirici, Önder Kurç, Mitra Jalilzadeh, Süleyman Aşır, and Deniz Türkmen
- Subjects
Chemistry ,QD1-999 - Published
- 2022
- Full Text
- View/download PDF
7. Molecularly Imprinted Polymers Based Surface Plasmon Resonance Sensor for Sulfamethoxazole Detection
- Author
-
Önder Kurç and Deniz Türkmen
- Subjects
Antibiotic ,sulfamethoxazole ,nanofilm chip ,molecularly imprinted polymers (MIP) ,surface plasmon resonance (SPR) ,Applied optics. Photonics ,TA1501-1820 - Abstract
Abstract Sulfamethoxazole (SMX) is a sulfonamide antibiotic primarily used to treat urinary tract infections and used in veterinary and industrialized husbandry to treat diseases and food additives. Like other antibiotics, SMX is considered as a pollutant in water and food that threaten local life. This study developed a surface plasmon resonance (SPR) sensor chip that is fast, highly selective, and reusable, and requires no pretreatment for detecting SMX. As a receptor, SMX imprinted methacrylic acid-2-hydroxyethyl methacrylate-ethylene glycol dimethacrylate polymer [poly(MAA-HEMA-EGDMA)] was used. The surface of the gold SPR chips was coated with a drop-casting method. The nanofilm coated chips were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), ellipsometer, contact angle measurement, and Fourier-transform infrared spectrometry (FTIR). Imprinting factor (IF) was calculated as: ΔR[MIP(molecularly imprinted polymers)]/ΔR[NIP(non-imprinted)]=12/3.5=3.4. Limit of detection (LOD) and limit of quantification (LOQ) values were calculated with 3 s/m and 10 s/m methods, and the results were found to be 0.001 1 µg/L for LOD 0.003 4 µg/L for LOQ. Adsorption studies on both standard SMX solution and commercial milk samples were applied. Also, we investigated the developed chip’s reusability, storability, and selectivity with amoxicillin and cefalexin.
- Published
- 2022
- Full Text
- View/download PDF
8. Simple and Fast Pesticide Nanosensors: Example of Surface Plasmon Resonance Coumaphos Nanosensor
- Author
-
Beste Oymen, Mitra Jalilzadeh, Fatma Yılmaz, Süleyman Aşır, Deniz Türkmen, and Adil Denizli
- Subjects
molecular imprinting ,surface plasmon resonance ,nanosensor ,nanofilm ,coumaphos ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
Here, a molecular imprinting technique was employed to create an SPR-based nanosensor for the selective and sensitive detection of organophosphate-based coumaphos, a toxic insecticide/veterinary drug often used. To achieve this, UV polymerization was used to create polymeric nanofilms using N-methacryloyl-l-cysteine methyl ester, ethylene glycol dimethacrylate, and 2-hydroxyethyl methacrylate, which are functional monomers, cross-linkers, and hydrophilicity enabling agents, respectively. Several methods, including scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle (CA) analyses, were used to characterize the nanofilms. Using coumaphos-imprinted SPR (CIP-SPR) and non-imprinted SPR (NIP-SPR) nanosensor chips, the kinetic evaluations of coumaphos sensing were investigated. The created CIP-SPR nanosensor demonstrated high selectivity to the coumaphos molecule compared to similar competitor molecules, including diazinon, pirimiphos-methyl, pyridaphenthion, phosalone, N-2,4(dimethylphenyl) formamide, 2,4-dimethylaniline, dimethoate, and phosmet. Additionally, there is a magnificent linear relationship for the concentration range of 0.1–250 ppb, with a low limit of detection (LOD) and limit of quantification (LOQ) of 0.001 and 0.003 ppb, respectively, and a high imprinting factor (I.F.4.4) for coumaphos. The Langmuir adsorption model is the best appropriate thermodynamic approach for the nanosensor. Intraday trials were performed three times with five repetitions to statistically evaluate the CIP-SPR nanosensor’s reusability. Reusability investigations for the two weeks of interday analyses also indicated the three-dimensional stability of the CIP-SPR nanosensor. The remarkable reusability and reproducibility of the procedure are indicated by an RSD% result of less than 1.5. Therefore, it has been determined that the generated CIP-SPR nanosensors are highly selective, rapidly responsive, simple to use, reusable, and sensitive for coumaphos detection in an aqueous solution. An amino acid, which was used to detect coumaphos, included a CIP-SPR nanosensor manufactured without complicated coupling methods and labelling processes. Liquid chromatography with tandem mass spectrometry (LC/MS-MS) studies was performed for the validation studies of the SPR.
- Published
- 2023
- Full Text
- View/download PDF
9. Preparation of Immobilised 17β-Estradiol-Imprinted Nanoparticles onto Bacterial Cellulose Nanofibres to Use for the Removal of 17β-Estradiol from Wastewater
- Author
-
İlker Koç, Koray Şarkaya, Deniz Türkmen, Süleyman Aşır, and Adil Denizli
- Subjects
17β-estradiol ,adsorption ,bacterial cellulose nanofibres ,molecular imprinting ,Organic chemistry ,QD241-441 - Abstract
Estradiol, a phenolic steroid oestrogen, is one of the endocrine-disrupting chemicals (EDCs) found in natural and tap waters. The detection and removal of EDCs is attracting attention daily as they negatively affect animals’ and humans’ endocrine functions and physiological conditions. Therefore, developing a fast and practical method for the selective removal of EDCs from waters is essential. In this study, we prepared 17β-estradiol (E2)-imprinted HEMA-based nanoparticles onto bacterial cellulose nanofibres (E2-NP/BC-NFs) to use for the removal of E2 from wastewater. FT-IR and NMR confirmed the structure of the functional monomer. The composite system was characterised by BET, SEM, µCT, contact angle, and swelling tests. Additionally, the non-imprinted bacterial cellulose nanofibres (NIP/BC-NFs) were prepared to compare the results of E2-NP/BC-NFs. Adsorption of E2 from aqueous solutions was performed in batch mode and investigated via several parameters for optimisation conditions. The effect of pH studies was examined in the 4.0–8.0 range using acetate and phosphate buffers and a concentration of E2 of 0.5 mg/mL. The maximum E2 adsorption amount was 254 µg/g phosphate buffer at 45 °C. The experimental data show that the Langmuir is a relevant isotherm model for E2 adsorption. Additionally, the relevant kinetic model was the pseudo-second-order kinetic model. It was observed that the adsorption process reached equilibrium in less than 20 min. The E2 adsorption decreased with the increase in salt at varying salt concentrations. The selectivity studies were performed using cholesterol and stigmasterol as competing steroids. The results show that E2 is 46.0 times more selective than cholesterol and 21.0 times more selective than stigmasterol. According to the results, the relative selectivity coefficients for E2/cholesterol and E2/stigmasterol were 8.38 and 86.6 times greater for E2-NP/BC-NFs than for E2-NP/BC-NFs, respectively. The synthesised composite systems were repeated ten times to assess the reusability of E2-NP/BC-NFs.
- Published
- 2023
- Full Text
- View/download PDF
10. Heavy Metal Ions Removal From Wastewater Using Cryogels: A Review
- Author
-
Deniz Türkmen, Monireh Bakhshpour, Semra Akgönüllü, Süleyman Aşır, and Adil Denizli
- Subjects
heavy metal ion ,adsorbents ,cryogels ,removal ,wastewater ,Economic theory. Demography ,HB1-3840 - Abstract
Water contamination by heavy metal pollution is induced by rapid industrialization and urbanization. Removal of heavy metal ions from wastewater is of prime importance for a clean environment and human health. The heavy metal problem is seriously threatened to human health. In addition, these metals are toxic and carcinogenic. They cause serious problems for aquatic ecosystems and especially humans. Different methods have been utilized to remove heavy metals from the wastewater, such as membrane filtration, adsorption, and ion exchange. Adsorption is one of the most efficient processes to clean contaminated water. The adsorption process presents advantages such as availability, low cost, and eco-friendly nature. The commercial adsorbents and the polymeric adsorbents are showed a high removal capacity for heavy metal ions capturing and removing from wastewater. Several researchers have widely used cryogels as a unique bio-adsorbent for heavy metals removal from wastewaters. Cryogels are efficient for the removal of heavy metal ions. This manuscript comprehensively and critically reviews current research in heavy metal adsorption by cryogels that prepared various technology and highlights the main advantages of these materials. Cryogels are synthetic polymers used in adsorption experiments in recent years. Because of their macropores, they provide an excellent advantage as an adsorbent in continuous and batch adsorption processes. The process applied for cryogel formation is called cryogelation. These macroporous gel matrices can be produced with different shapes and the gels are of interest in the bioseparation area since they can meet needs that conventional chromatographic media are less suitable to fulfill. The structure, synthesis, and composition of various cryogels are presented. Cryogels are generally synthesized by bulk polymerization under semifrozen conditions at −12 and 18°C for 12 to 24 h. The cryogels have a high removal capacity rate of over 90%. In the cryogels based studies, Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermal, surface area, elemental, and computerized microtomography (μCT) analyses can be used for the characterization of cryogels structure.
- Published
- 2022
- Full Text
- View/download PDF
11. The Triangulation WIthin a STudy (TWIST) framework for causal inference within pharmacogenetic research.
- Author
-
Jack Bowden, Luke C Pilling, Deniz Türkmen, Chia-Ling Kuo, and David Melzer
- Subjects
Genetics ,QH426-470 - Abstract
In this paper we review the methodological underpinnings of the general pharmacogenetic approach for uncovering genetically-driven treatment effect heterogeneity. This typically utilises only individuals who are treated and relies on fairly strong baseline assumptions to estimate what we term the 'genetically moderated treatment effect' (GMTE). When these assumptions are seriously violated, we show that a robust but less efficient estimate of the GMTE that incorporates information on the population of untreated individuals can instead be used. In cases of partial violation, we clarify when Mendelian randomization and a modified confounder adjustment method can also yield consistent estimates for the GMTE. A decision framework is then described to decide when a particular estimation strategy is most appropriate and how specific estimators can be combined to further improve efficiency. Triangulation of evidence from different data sources, each with their inherent biases and limitations, is becoming a well established principle for strengthening causal analysis. We call our framework 'Triangulation WIthin a STudy' (TWIST)' in order to emphasise that an analysis in this spirit is also possible within a single data set, using causal estimates that are approximately uncorrelated, but reliant on different sets of assumptions. We illustrate these approaches by re-analysing primary-care-linked UK Biobank data relating to CYP2C19 genetic variants, Clopidogrel use and stroke risk, and data relating to APOE genetic variants, statin use and Coronary Artery Disease.
- Published
- 2021
- Full Text
- View/download PDF
12. Gold-Modified Molecularly Imprinted N-Methacryloyl-(l)-phenylalanine-containing Electrodes for Electrochemical Detection of Dopamine
- Author
-
Nemah Abu Shama, Süleyman Aşır, Mehmet Ozsoz, Ilgım Göktürk, Deniz Türkmen, Fatma Yılmaz, and Adil Denizli
- Subjects
dopamine ,gold nanoparticles ,pencil graphite electrode ,molecularly imprinted polymer ,differential pulse voltammetry ,cyclic voltammetry ,Technology ,Biology (General) ,QH301-705.5 - Abstract
A molecularly imprinted polymer-based pencil graphite electrode (MIP PGE) sensor, modified with gold nanoparticles, was utilized for the detection of dopamine in the presence of other biochemical compounds using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), depending on its strong electroactivity function. The pulse voltammetry methods recorded the highest response. In addition to the high oxidation rate of DA and the other biomolecule interferences available in the sample matrix used, which cause overlapping voltammograms, we aimed to differentiate them in a highly sensitive limit of detection range. The calibration curves for DA were obtained using the CV and DPV over the concentration range of 0.395–3.96 nM in 0.1 M phosphate buffer solution (PBS) at pH 7.4 with a correlation coefficient of 0.996 and a detection limit of 0.193 nM. The electrochemical technique was employed to detect DA molecules quantitatively in human blood plasma selected as real samples without applying any pre-treatment processes. MIP electrodes proved their ability to detect DA with high selectivity, even with epinephrine and norepinephrine competitor molecules and interferences, such as ascorbic acid (AA). The high level of recognition achieved by molecularly imprinted polymers (MIPs) is essential for many biological and pharmaceutical studies.
- Published
- 2022
- Full Text
- View/download PDF
13. Poly-()-histidine immobilized cryogels for lysozyme purification
- Author
-
Duygu Çimen, Deniz Türkmen, and Adil Denizli
- Subjects
Physical and theoretical chemistry ,QD450-801 - Abstract
Immobilized metal ion affinity chromatography is one of the methods used for the adsorption of proteins. In this study, poly(glycidyl methacrylate) cryogel discs were prepared by free radical polymerization. The metal chelating groups were polymeric chain of poly-( l )-histidine (mol wt ≥ 5000) having poly-imidazole ring sequence. Then, Cu(II), Zn(II), and Ni(II) ions were separately chelated on the poly-( l )-histidine immobilized poly(glycidyl methacrylate) cryogel discs to be used in immobilized metal ion affinity chromatography separation of lysozyme. The swelling test, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, and scanning electron microscopy were performed to characterize both poly(glycidyl methacrylate) and poly-( l )-histidine immobilized poly(glycidyl methacrylate) cryogel discs. The effects of the pH, lysozyme concentration, adsorption time, and ionic strength on the adsorption capacity were studied. These parameters were varied between 4.0 and 8.0 for pH, 0.0 and 2.0 mg/ml for initial lysozyme concentration, 0 and 120 min for adsorption time, and 0.0 and 1.0 µM for ionic strength. The maximum lysozyme adsorption capacity of the Cu(II), Zn(II), and Ni(II) ions chelated poly-( l )-histidine immobilized poly(glycidyl methacrylate) cryogel discs was 36.4, 26.8, and 17.3 mg/g cryogel, respectively. Desorption of lysozyme from cryogel discs was easily achieved by 1.0 M NaCI solution. Repeated adsorption-elution processes showed that these cryogel discs were suitable for repeatable lysozyme adsorption. Adsorption isotherms fitted to Langmuir model and adsorption kinetics suited to pseudo-second order model. Thermodynamic parameters (i.e. ΔH°, ΔS°, ΔG°) were also calculated from Langmuir isotherms at different temperatures.
- Published
- 2016
- Full Text
- View/download PDF
14. Statin treatment effectiveness and the SLCO1B1 *5 reduced function genotype: Long‐term outcomes in women and men
- Author
-
Deniz Türkmen, Jane A. H. Masoli, Chia‐Ling Kuo, Jack Bowden, David Melzer, and Luke C. Pilling
- Subjects
Male ,Pharmacology ,Simvastatin ,Cholesterol ,Treatment Outcome ,Genotype ,Liver-Specific Organic Anion Transporter 1 ,Humans ,Female ,Pharmacology (medical) ,Hydroxymethylglutaryl-CoA Reductase Inhibitors - Abstract
To estimate the effect of rs4149056 (SLCO1B1*5) genotype (decreases statin transport) on cholesterol control and treatment duration in male and female primary care patients prescribed common statin medications.This study comprised 69 185 European-ancestry UK Biobank cohort participants prescribed simvastatin or atorvastatin (aged 40-79 years at first prescription, treatment duration 1 month to 29 years, mean 5.7 years). Principal outcomes were clinically high total cholesterol (5 mmol/L) at baseline, plus treatment discontinuation.A total of 48.4% of 591 females homozygous for SLCO1B1*5 decreased function genotype had raised cholesterol vs 41.7% of those with functioning SLCO1B1 (odds ratio 1.31, 95% confidence interval [CI] 1.1-1.55, P = .001). Fewer males had high cholesterol and the genotype effect was attenuated. In primary care prescribing, females homozygous for SLCO1B1*5 were more likely to stop receiving these statins (29.5%) than women with normal SLCO1B1 (25.7%) (hazard ratio [HR] 1.19, 95% CI 1.03-1.37, P = .01), amounting to five discontinuations per 100 statin-years in the SLCO1B1*5 group vs four in the normal SLCO1B1 function group. This remained significant after the first year of treatment (HR for discontinuing1 year after first prescription 1.3, 95% CI 1.08-1.56, P = .006). In men SLCO1B1*5 was only associated with treatment discontinuation in the first year.In this large community sample of patients on commonly prescribed statins, the SLCO1B1*5 decreased function variant had much larger effects on cholesterol control and treatment duration in women than in men. Efforts to improve the effectiveness of statin therapy in women may need to include SLCO1B1*5 genotype-guided statin selection.
- Published
- 2022
15. SOCIAL MEDIA USAGE LEVELS AND PREFERENCES OF THE BABY BOOMERS, GEN X, GEN Y, GEN Z
- Author
-
Gökhan Alptekin, Deniz Türkmen, and Halis Adnan Arslantaş
- Subjects
Modeling and Simulation - Abstract
Bu araştırma, Eskişehir İli Odunpazarı ve Tepebaşı ilçelerinde ikamet eden ve farklı kuşakları temsil ettiği kabul edilen bireylerin sosyal medya kullanım düzeyleri ve tercihlerini “süreklilik” ve “yetkinlik” boyutu açısından ele alan bir araştırmadır. Araştırmada tarama modeli kullanılmıştır. Tarama modeli, çok sayıda elemanın oluşturduğu bir evrende, evren hakkında genel bir kanıya varmak amacıyla evrenin tamamı yahut ondan alınacak bir grup üzerinde yapılan tarama kodifikasyonudur (Karasar, 2012). Araştırmanın çalışma grubunu kent merkezinde yaşayan 877 kişi oluşturmaktadır. Araştırmanın verileri Deniz ve Tutgun-Ünal (2019) tarafından geliştirilen “Sosyal Medya Kullanımı Ölçeği” kullanılarak çevrimiçi ortamda toplanmıştır. Araştırmada elde edilen bulgular; (1) Kuşaklar sosyal medya ağlarına erişimde en çok akıllı telefon kullanmaktadır. (2) BabyBoomer ve X kuşağı en çok Facebook’u kullanmayı tercih ederken, Y ve Z kuşağı ise en çok İnstagram’ı kullanmaktadır. (3) BabyBoomer, Y ve Z kuşakları sosyal medyada en fazla video ve müzik içeriklerini beğenirken, X kuşağı ise en fazla haber içeriklerini beğenmektedir.(4) Kuşaklar süreklilik ve yetkinlik boyutlarında sosyal medyayı orta düzeyde kullanmaktadır. (5) Y ve Z kuşağı, BabyBoomer ve X kuşağına göre sosyal medya kullanımında süreklilik sağlamakta ve kendilerini bu konuda daha yetkin bulmaktadırlar. (6) Z kuşağı kadınları aynı kuşakta bulunan erkeklere göre sosyal medya kullanımında süreklilik sağlayan cinsiyeti temsil etmektedir.
- Published
- 2021
16. Calcium-channel blockers: Clinical outcome associations with reported pharmacogenetics variants in 32 000 patients
- Author
-
Deniz Türkmen, Jane A. H. Masoli, João Delgado, Chia‐Ling Kuo, Jack Bowden, David Melzer, and Luke C. Pilling
- Subjects
Pharmacology ,Pharmacology (medical) - Abstract
Pharmacogenetic variants impact dihydropyridine calcium-channel blockers (dCCBs; e.g., amlodipine) treatment efficacy, yet evidence on clinical outcomes in routine primary care is limited. Reported associations in pharmacogenomics knowledge base PharmGKB have weak supporting evidence. We aimed to estimate associations between reported pharmacogenetic variants and incident adverse events in a community-based cohort prescribed dCCB.We analysed up to 32 360 UK Biobank participants prescribed dCCB in primary care (from UK general practices, 1990-2017). We investigated 23 genetic variants. Outcomes were incident diagnosis of coronary heart disease, heart failure (HF), chronic kidney disease, oedema and switching antihypertensive medication.Participants were aged 40-79 years at first dCCB prescription. Carriers of rs877087 T allele in RYR3 had increased risk of hazard ratio (HF 1.13: 95% confidence interval 1.02 to 1.25, P = .02). Although nonsignificant after multiple testing correction, the association is consistent with prior evidence. We estimated that if rs877087 T allele could experience the same treatment effect as noncarriers, the incidence of HF in patients prescribed dCCB would reduce by 9.2% (95% confidence interval 3.1 to 15.4). In patients with a history of heart disease prior to dCCB (n = 2296), rs877087 homozygotes had increased risk of new coronary heart disease or HF compared to CC variant. rs10898815 in NUMA1 and rs776746 in CYP3A5 increased likelihood of switching to an alternative antihypertensive. The remaining variants were not strongly or consistently associated with studied outcomes.Patients with common genetic variants in NUMA1, CYP3A5 and RYR3 had increased adverse clinical outcomes. Work is needed to establish whether outcomes of dCCB prescribing could be improved by prior knowledge of pharmacogenetics variants supported by clinical evidence of association with adverse events.
- Published
- 2022
17. Investigation of High School Students’ Attitudes Toward Violence in Terms of Some Variables: Eskisehir Sample
- Author
-
Hilal Baş, Emine Neslioğlu, and Deniz Türkmen
- Subjects
Data collection ,Academic year ,media_common.quotation_subject ,education ,Compassion ,Beşeri Bilimler, Ortak Disiplinler ,General Medicine ,Commit ,Social value orientations ,Humanities, Multidisciplinary ,Developmental psychology ,Adolescence,Violence,Attitude toward violence ,Sociology ,Scale (social sciences) ,Helpfulness ,Ergenlik,Şiddet,Şiddete Yönelik Tutum ,Psychology ,Sosyoloji ,Curriculum ,media_common - Abstract
Günümüzde insanlığın karşı karşıya bulunduğu başlıca sorunlarından biri de şiddettir. Bu sorununçözülmesi için bireylerin toplumsal ve bireysel özelliklerinin detaylı bir şekilde incelenmesi ve şiddeteyönelme sebeplerinin ortaya çıkarılması gerekmektedir. Ergenlik, şiddet davranışının sıklıkla görüldüğübir gelişim dönemidir. Bu araştırmanın amacı, ergenlerin şiddete yönelik tutumlarının, cinsiyet, yaş, okultürü ve anne-babanın eğitim durumu değişkenlerine göre incelenmesidir. Araştırmanın örneklem grubu,Eskişehir İli Milli Eğitim Müdürlüğüne bağlı ve il merkezinde bulunan Anadolu Lisesi, İmam- Hatip Lisesi,Sosyal Bilimler Lisesi, Fen Lisesi, Mesleki ve Teknik Anadolu Lisesi olmak üzere rastgele seçilen beş farklıokul türünde, 2019-2020 eğitim-öğretim yılında eğitim gören, 140’ı kız, 173’ü erkek olmak üzere toplam313 lise öğrencisinden oluşmaktadır. Araştırma tarama modelli ve betimsel bir çalışmadır. Veri toplamaaracı olarak “Kişisel Bilgi Formu” ve “Şiddete Yönelik Tutum Ölçeği” kullanılmıştır. Verilerin analizinde“t-Testi” ve “Tek Yönlü Varyans Analizi” kullanılmıştır. Araştırma sonucunda, ergenlerin şiddete yöneliktutumlarında cinsiyet ve okul türü faktöründe anlamlı farklılık olduğu saptanırken, yaş ve ebeveynlerineğitim düzeyi değişkenleri açısından anlamlı farklılık tespit edilmemiştir. Çalışma sonucunda, katılımcıların%41.9`u “Gerektiğinde kaba kuvvet kullanırım” ifadesine katıldığını belirtmiştir. Öğrencilerin okuldakişiddeti daha çok fiziksel şiddet olarak gördüğü ortaya çıkmaktadır. Elde edilen bulgular doğrultusunda;anne babaların konuyla ilgili bilinçlendirilmelerine yönelik çalışmaların artırılması, ergenlere şiddeteyönelmeden etkili problem çözme yöntemlerinin kazandırılmasına yönelik çalışmalar yapılması, eğitimmüfredatında bütünleşmeyi sağlayan sevgi, saygı, güven, yardımseverlik gibi ortak sosyal değerlerinkazandırılmasına yönelik etkinliklere daha çok yer verilmesi ve okullarda şiddeti önleme ve izlemeçalışmalarının artırılması önerilmektedir ., Violence is one of the main problems that the public encounter today. In order this problem to be solved,the social and personal features of the individuals must be examined and the reasons of their tendencyto violence must be detected. The adolescence is a developmental period in which acts of violence areencountered more often. The aim of the present study was to investigate adolescents’ attitudes towardviolence in terms of their gender, age, type of school and parents’ educational level. The sample groupof the study consisted of 313 high school students (140 females and 173 males), studying in five differenttypes of state high schools in the center of Eskişehir city in 2019- 2020 academic year. The descriptivesurvey model was used in the study. As data collection tools, “Personal Information Form” and “TheAttitudes toward Violence Scale” were used. In the analysis of the data, “t-test” and “one-way analysis ofvariance” were used. As a result of the study, that there is a significant level of difference between the highschool students’ attitude toward violence and gender and type of school, whereas, there is not a significantlevel of difference in terms of age and parents’ educational level has been found out. In the conlusion, the41.9 % of the sample group agreed with the expression “I commit violence when it is needed.” It has beenfound out that violence is often seen as a physical thing by the students in the schools. In accordancewith the findings, it is suggested to increase awareness-raising activities for parents about the issue, toorganize trainings to help adolescents to make use of effective problem-solving methods without usingviolence, to include more facilities in the curriculum to make social values like compassion, respect, trust,helpfulness be acquired; and also it is suggested to extend facilities of violence prevention and monitoringin the schools.
- Published
- 2020
18. Molecular Imprinting Technology for Biomimetic Assemblies
- Author
-
Sevgi Aslıyüce, Semra Akgönüllü, Ilgım Göktürk, Adil Denizli, Deniz Türkmen, Nilay Bereli, Duygu Çimen, and Handan Yavuz
- Subjects
Molecular imprinting,biomimetic,separation,sensing,polymer brushes,artificial membranes,drug delivery,tissue engineering ,Engineering ,Chemistry ,Mühendislik ,Nanotechnology ,Molecular imprinting - Abstract
The term biomimetic can be simply defined as the examination of nature. The scientists inspired by the enormous diversity of nature to solve human problems or facilitate daily life by mimicking natural models, systems, and elements especially in the biomedical and therapeutic applications to make better drugs, artificial organs, sensing instruments, etc. Biological recognition elements like proteins, antibodies, enzymes, DNA, lectins, aptamers, cells, and viruses have been heavily used to ensure specificity in such applications in spite of their lack of stability and reusability. However, in the last two decades molecularly imprinted polymers, MIPs, have been synthesized as an alternative to mimic natural biological interactions for a broad spectrum of templates by means of coordinating functional monomers around template in the presence of cross-linker. This review will outline the broad contours of biomimetics prepared by molecular imprinting techniques and their practical applications in the separation techniques, tissue engineering applications, biomimetic surfaces, sensors, artificial membranes, and drug delivery systems.
- Published
- 2020
19. The Use of Social Media as a Means of Political Communication: Twitter Samples of Ankara Deputies
- Author
-
Deniz Türkmen and Münir Özkan
- Subjects
General Medicine - Abstract
Bu çalışmanın amacı, Ankara milletvekillerinin bir sosyal medya aracı olan Twitter ’ı kullanım sıklıklarını tespit ederek, mevcut Twitter hesaplarından temsil ettikleri Ankara hakkındaki gelişmeleri, sorunları ne sıklıkla kamuoyuna paylaştıklarını belirlemektir. Yapılan çalışmada 2018 yılının 15 Ekim -15 Kasım tarihleri arasında, Ankara’yı temsil eden 36 milletvekilinin Twitter ’daki şahsi hesaplarından yaptıkları paylaşımlar incelenmiştir. Bu incelemeler yapılırken içerik analizi yöntemi uygulanmıştır. Elde edilen bulgulara göre, belirtilen tarih aralığında 33 milletvekilinin toplamda 2916 adet paylaşım yaptığı tespit edilmiş olup, Ankara milletvekillerinin günlük tweet atma oranı %2,94 olarak saptanmıştır. Milletvekillerinin içinde en çok tweet AK Parti milletvekilleri tarafından paylaşılırken en az paylaşımı BBP milletvekilinin yaptığı görülmüştür. Toplamda AK Parti milletvekilleri 930, CHP vekilleri 846, MHP vekilleri 524, İYİ Parti milletvekilleri 315, HDP vekili 223 ve BBP milletvekili 78 adet paylaşım yapmıştır. Vekillerin tweetlerde ele aldıkları konular incelendiğinde %87,1 oranında ulusal konular ile ilgili paylaşım yaptıkları görülürken, %12,8 oranında yerel konular ile ilgili paylaşım yaptıkları tespit edilmiştir.
- Published
- 2020
20. Statin treatment effectiveness and the SLCO1B1*5 reduced function genotype: long-term outcomes in women and men
- Author
-
David Melzer, Deniz Türkmen, Chia-Ling Kuo, Luke C. Pilling, Jack Bowden, and Jane A. H. Masoli
- Subjects
medicine.medical_specialty ,Statin ,business.industry ,medicine.drug_class ,Atorvastatin ,Hazard ratio ,Odds ratio ,medicine.disease ,High cholesterol ,Confidence interval ,Discontinuation ,Internal medicine ,Cohort ,Medicine ,business ,medicine.drug - Abstract
ObjectiveTo estimate the effect of the SLCO1B1*5 genotype (decreases statin transport) on cholesterol control and treatment duration in male and female primary care patients prescribed common statin medications.Methods and Analysis69,185 European-ancestry UK Biobank cohort participants prescribed simvastatin or atorvastatin (aged 40 to 79 years at first prescription; treatment duration 1 month to 29 years, mean 5.7 years). Principal outcomes were clinically high total cholesterol (>5mmol/L) at baseline, plus treatment discontinuation.Results48.4% of 591 females homozygous for SLCO1B1*5 decreased function genotype had raised cholesterol, vs. 41.7% of those with functioning SLCO1B1 (Odds Ratio 1.31: 95% Confidence Intervals 1.1 to 1.55, p=0.001). Fewer males had high cholesterol, and the genotype effect was attenuated. In primary care prescribing, females homozygous for SLCO1B1*5 were more likely to stop receiving these statins (29.5%) than women with normal SLCO1B1 (25.7%) (Hazard Ratio 1.19: 95%CI 1.03 to 1.37, p=0.01), amounting to five discontinuations per 100 statin-years in the SLCO1B1*5 group vs four in the normal SLCO1B1 function group. This remained significant after the first year of treatment (HR for discontinuing >1 year after first prescription 1.3: 95%CI 1.08 to 1.56; p=0.006). In men SLCO1B1*5 was only associated with treatment discontinuation in the first year.ConclusionsIn this large community sample of patients on commonly prescribed statins, the SLCO1B1*5 decreased function variant had much larger effects on cholesterol control and treatment duration in women than in men. Efforts to improve effectiveness of statin therapy in women may need to include SLCO1B1*5 genotype-guided statin selection.What is already known about this subjectGenetic variants affecting SLCO1B1 (statin transporter) gene function increase concentrations of unmetabolized statin molecules (mostly simvastatin and atorvastatin). Previous studies of statin-treated patients have reported reduced likelihood of achieving target cholesterol levels plus increased adverse effects and medication non-adherence mainly in the first year of treatment.However, little data have been available on key outcomes over longer follow-ups or on outcomes by sex, despite large differences in statin treatment patterns between men and women.What this study addsIn 69,185 UK Biobank participants reporting simvastatin or atorvastatin use at baseline assessment, substantially more women had clinically high total cholesterol (>5 mmol/L) compared to men (42% vs. 25%). Female carriers of the SLCO1B1*5 (decreased SLCO1B1 function) genetic variant were especially likely to have high cholesterol, despite being on statin treatment.In primary care records of atorvastatin and simvastatin prescribing (>10 years follow-up), female carriers of SLCO1B1*5 were more likely to stop statins. In men, SLCO1B1*5 was only associated with discontinuing statin treatment in the first year after starting treatment.
- Published
- 2021
21. Magnetic Nanoparticles and Their Biomedical Applications
- Author
-
Tahira Qureshi, Fatma Denizli, Kemal Çetin, Adil Denizli, Handan Yavuz, and Deniz Türkmen
- Subjects
chemistry.chemical_classification ,Materials science ,Magnetism ,Biomolecule ,Mühendislik ,food and beverages ,Nanoparticle ,Nanotechnology ,Biomedical applications,bioseparation,drug delivery,hyperthermia,magnetic nanoparticle ,Polymer ,equipment and supplies ,Functional diversity ,Engineering ,chemistry ,Drug delivery ,Magnetofection ,Magnetic nanoparticles ,human activities - Abstract
The combination of magnetism and nanotechnology has presented promising materials: magnetic nanoparticles. These materials have been getting more attention due to their “size‐dependent functionality”. There is a critical size for nanoparticles that their properties change. Materials with various functions can be synthesized with the desired properties since a wide range of polymers including natural and synthetic polymers can be utilized in the production of the magnetic nanoparticles. Furthermore, they can be more selective and specific with the conjugation target-specific ligands. This structural and functional diversity enables these materials to be used in a wide range of areas. In this review, we discuss the main components of the magnetic nanoparticles and their examples in biomedical applications. They can be used as contrast agents in magnetic resonance imaging; delivery systems in the controlled release of therapeutic agents; supporting materials for separation, isolation, and purification of biomolecules. They can be also functioned in hyperthermia and magnetofection for gene therapy. However, even though their increasing research interest, magnetic nanoparticles still need to be improved to be more popular in the commercial area. We hope that these functional materials will present promising possibilities in nanotechnology and biomedicine in near future.
- Published
- 2019
22. Bir iksa sisteminin iki ve üç boyutlu sonlu elemanlaryöntemi ile çözülmesi ve saha ölçümleri ilekarşılaştırılması
- Author
-
Yilmaz, Deniz Türkmen, Lav, Musaffa Ayşen, and İnşaat Mühendisliği Ana Bilim Dalı
- Subjects
İnşaat Mühendisliği ,Deep excavation ,Civil Engineering - Abstract
Artan kentselleşmenin sonucu nüfusun ihitiyaçlarını karşılamak amacı ile konut,sanayi yapıları, iş merkezleri, spor merkezleri, altyapı projeleri gibi inşaat projelerininartmasına yol açmaktadır. Yoğun nüfuslu kentlerde mevcut arsaların kullanımını enefektif şekilde değerlendirme mecburiyeti doğmuştur. Bu sebeple arazileringörünmeyen kısımları da inşaat alanlarına dönüşmüştür. Bu alanlarda açılan kazıçukurlarını desteklemek amacı ile tasarlanan iksa sistemi yapılırken sisteme etkiyecekolan toprak ve su basıncının yanı sıra sürsarj basınçlarının hesaplanmasıgerekmektedir. İksa sistemine etkiyecek olan yükleri belirlemek için sağlıklı bir zeminetüdünün yapılması gerekmektedir. Yanlış yapılan zemin etüdleri neticesindetasarlanan iksa sistemleri neticesinde çevre yapılarda ve yollarda yapısal hasaroluşabilmektedir. Oluşan hasarlar izin verilen sınırlar içeresinde kalmadığı takdirdecan ve mal kaybına yol açmaktadır. Tasarımı yapılan iksa sisteminin hesaplananyükleri izin verilen deplasmanlar sınırında tasarım ömrü süresince karşılamasıgerekmektedir.Çalışmanın amacı, aletsel gözlemlerin derin kazılardaki önemi ve faydasınıngösterilmesidir. Bu çalışma da tasarımı yapılmış olan derin kazı sisteminin analizlersonucu elde edilen deplasmanlarla sahada gerçekleşen deplasmanlarınınkarşılaştırılması anlatılmıştır.Tez kapsamında, İstanbul ili Avrupa Yakası kısmında yapılacak olan bir metro hatınaait istasyonunun kazı destek sistemi için öncelikle literatürdeki veriler ışığında sahadayapılan sondaj verilerine göre zemin parametreleri belirlenmiştir. Zemin profili, yeraltısuyu, sürsarj yükleri ve kesitler belirlendikten sonra PLAXIS 2D ve PLAXIS 3Dyazılımı ile analizler gerçekleştirilmiştir.Tez çalışmasının birinci bölümünde iksa sistemlerinin öneminden bahsedilmiştir.İkinci bölümünde ise iksa sistemlerine etkiyen yanal toprak basınçları hakkında bilgiverilmiştir. Üçüncü bölümde yanal toprak basınçları ve çevresel yükleri sağlıklı birşekilde taşımak amacıyla gerekli yatay-düşey destekler anlatılmıştır. Sonraki bölümdeiksa sistemlerinin en önemli bir parçası olan geoteknik enstürümantasyonlar hakkındabilgi verilmiştir. Tezin beşinci bölümünde sonlu elemanlar yöntemi ve geoteknikanalizlerde kullanılan Plaxis programı tanıtılmıştır.Tez kapsamında Plaxis 2D ve Plaxis 3D ile yapılan analizler sonucunda elde edilendeplasmanlar ile sahada gerekli enstürümantasyonlar ile ölçülen gerçek deplasmanlarkarşılaştırılmıştır.Sonuç kısmında ise metro projesine ait istasyon için yapılan analizlerin sonuçları ileinklinometre ölçümlerinin karşılaştırılması değerlendirilmiştir. Belirlenen idealize zemin profili için farklı kazı uzunluğuna sahip kazı çukurunun çevre yapılarınoturmasına etkisi incelenmiş ve tez çalışması tamamlanmıştır. Since the urbanization trend continues to grow throughout the world, so does the needof construction projects as the ever-growing human population demands and requiresnew houses, industrial facilities, social centers and infrastructures. This increase indemands made it a necessity in central cities for the land to be used as efficient aspossible. As a result, the unseen parts of the land; the underground turned intoconstruction sites. But making deep excavations in order to make use of undergroundareas require additional engineering designs.When designing a support system for an excavation site, surcharge loads must be takeninto account in addition to earth and water pressure. To determine all loads that willeffect the support system, a healthy soil investigation must be carried out first. Withoutthe data from a healthy soil investigation, designing a support system might causedamage to nearby structures and roads. When exceeding the agreeable limits, thesedamages can lead to loss of lives or properties. The designed support system isexpected to compensate the loads within agreeable displacement limits as far as thedesign life.As one of the problems solved in geotechnical engineering, deep excavations are acomplex topic. This problem incorporates numerous factors which includes severalvertical and horizontal members. The basic logic behind this design is to transfer theearth and water pressure as well as surcharge loads effecting the system through thesevertical and horizontal members and eventually divert these loads into the soil. Whiledesigning the deep excavation support system, a lateral earth pressure distribution mustbe achieved behind the wall in order to determine final wall height and estimatesupport loads and bending moment of the wall. Unlike a standard excavation, whenconstructing the support system `top-down`; the deformation pattern would becomemuch more complex and inconsistent with the theoretical Rankine and Coulomb earthpressure distribution.The aim of this study is to show the importance and benefit of instrumentalobservations in deep excavations. This study contains comparison of a designed deepexcavation support systems displacements and actual displacements seen on site.Within the study, soil parameters for a deep excavation support system constructed asa part of subway construction in the European side of İstanbul were determined first.After determining the soil profile, ground water level, surcharge loads and sections;analyses were conducted using PLAXIS 2D and PLAXIS 3D software.The deep excavation system for the station structure will be approximately 21x99m.In the study area, surface elevations are fixed and the excavation height is 25.40m. Thedeep excavation system will be supported internally at 4 different levels. Reinforced concrete elements were preferred as internal support system in the first three levels,while steel pipe was preferred in the fourth level.In the first chapter of study, the reasons behind the increased use of deep excavationsand this methods importance in geotechnical engineering were addressed.Following these details, study continues with earth pressures which is the main factorbehind determining the dimensions of deep excavation support system elements.Prized scientists in Geotechnical Engineering such as Terzaghi, Peck andTschebotarioff proposed various loadings based on the cohesion levels of the soil.The third section of the study focused on the vertical and horizontal support elementsof the deep excavation support systems. Within the study; bored piles, diaphragm wallsand sheet pile walls were showed as vertical support elements. The comparison andevaluation of these elements were touched on in details in respect of productionmethod and difficulties in production. Furthermore; anchorages, soil nails and strutsupports were showed as horizontal support elements. In it a fact that anchorages areused more often in comparison to soil nails as anchorages provide greater carryingcapacity as a horizontal support element. Whereas the strut supports can also bepreferred as they can be produced a lot faster and are usually required less in number.Following these details, in the fourth section study focuses on the monitoring of deepexcavation support systems and surrounding structures. It is essential to monitor thebehavior of support systems to ensure the structural safety of deep excavations andother structures surrounding the excavation site. It is very common to see engineeringapplications which show different behavior than their original designs. Because of this,geotechnical instrumentation holds great importance in all engineering applications.To this purpose, the respective section of the study shows crack gauges, deformationmeasurements, extansometers, piezometers, reflectors and inclinometers in detail.During deep excavations, high levels of stresses are faced. To compensate thesestresses, diaphragm walls are often preferred as the safest system. The reason behindthis is that diaphragm walls are much more rigid in comparison to pile systems andthat they also allow displacements that will occur during the excavation to bemonitored easily. The most common way to monitor these displacements is withinclinometers. The deep excavation this study is based on is carried out usingdiaphragm walls and struts. The displacements during excavation were monitored withinclinometers.The fifth chapter of the study refers to finite elements method and the PLAXISsoftware. In principal, finite elements method bears the logic of reaching to the wholethrough working on small pieces. In the last century, the fast development ofcomputers made this method a frequently used supportive element in all engineeringsubjects. Today, finite elements method is used in many areas. One of the widelyknown software PLAXIS also uses finite elements method logic as its base in order tosolve complex geotechnical problems.In the analyzes, soil units were modeled using 'Hardening Soil' model, while rockunits were modeled using 'Mohr-Coulomb' structure model, structural elements were'plate' and struts were modeled using 'node-to-node anchor' elements.The analyses conducted in two-dimensions and three-dimensions were then comparedto on-site data. The results achieved after this comparison is as follows; The displacement behavior and values obtained in PLAXIS 2D and PLAXIS 3Danalyses were found out to be similar and within close range.Boscardin and Cording have developed a method for determining damage to existingstructures by angular rotation and horizontal unit deformations. According to thismethod, the displacement values obtained as a result of the analyzes were processedand the effect of displacements on the existing structures were examined and it wasobserved that the displacements in the structures remained in the negligible region intwo-dimensional and three-dimensional analyzes.When the results obtained from finite elements method was compared to actual on-sitedata, it was seen that the results from finite elements method were higher in value. Itis believed that the main reason behind this difference is the actual soil parameters arehigher than the parameters taken from literature of which the analyses were based onor that the soil profile differs.In respect of displacement behavior, inclinometer results showed similarity todisplacement results obtained through finite elements method.Internal forces of the diyaphram wall obtained through PLAXIS 2D and PLAXIS 3Danalyses were found out to be similar and within close range.In the conclusion, the inclinometer measurements and the results of the analyzes forthe station belonging to the subway project were evaluated and compared. For theidealized soil profile, the effect of excavation with different dimensions on thesettlement of the surrounding structures was investigated and the thesis study wascompleted. 104
- Published
- 2019
23. Poly-(<scp>l</scp>)-histidine immobilized cryogels for lysozyme purification
- Author
-
Deniz Türkmen, Duygu Çimen, and Adil Denizli
- Subjects
Glycidyl methacrylate ,General Chemical Engineering ,010401 analytical chemistry ,lcsh:QD450-801 ,lcsh:Physical and theoretical chemistry ,02 engineering and technology ,Surfaces and Interfaces ,General Chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Metal ,chemistry.chemical_compound ,Adsorption ,chemistry ,Affinity chromatography ,visual_art ,visual_art.visual_art_medium ,Lysozyme ,0210 nano-technology ,Histidine ,Nuclear chemistry - Abstract
Immobilized metal ion affinity chromatography is one of the methods used for the adsorption of proteins. In this study, poly(glycidyl methacrylate) cryogel discs were prepared by free radical polymerization. The metal chelating groups were polymeric chain of poly-( l )-histidine (mol wt ≥ 5000) having poly-imidazole ring sequence. Then, Cu(II), Zn(II), and Ni(II) ions were separately chelated on the poly-( l )-histidine immobilized poly(glycidyl methacrylate) cryogel discs to be used in immobilized metal ion affinity chromatography separation of lysozyme. The swelling test, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, and scanning electron microscopy were performed to characterize both poly(glycidyl methacrylate) and poly-( l )-histidine immobilized poly(glycidyl methacrylate) cryogel discs. The effects of the pH, lysozyme concentration, adsorption time, and ionic strength on the adsorption capacity were studied. These parameters were varied between 4.0 and 8.0 for pH, 0.0 and 2.0 mg/ml for initial lysozyme concentration, 0 and 120 min for adsorption time, and 0.0 and 1.0 µM for ionic strength. The maximum lysozyme adsorption capacity of the Cu(II), Zn(II), and Ni(II) ions chelated poly-( l )-histidine immobilized poly(glycidyl methacrylate) cryogel discs was 36.4, 26.8, and 17.3 mg/g cryogel, respectively. Desorption of lysozyme from cryogel discs was easily achieved by 1.0 M NaCI solution. Repeated adsorption-elution processes showed that these cryogel discs were suitable for repeatable lysozyme adsorption. Adsorption isotherms fitted to Langmuir model and adsorption kinetics suited to pseudo-second order model. Thermodynamic parameters (i.e. ΔH°, ΔS°, ΔG°) were also calculated from Langmuir isotherms at different temperatures.
- Published
- 2016
24. Megaporous poly(hydroxy ethylmethacrylate) based poly(glycidylmethacrylate-N-methacryloly-(l)-tryptophan) embedded composite cryogel
- Author
-
Işık Perçin, Ali Derazshamshir, Deniz Türkmen, Nilay Bereli, Huma Shaikh, and Fatma Yılmaz
- Subjects
Composite number ,Fungal Proteins ,Contact angle ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Adsorption ,Polymethacrylic Acids ,Specific surface area ,Physical and Theoretical Chemistry ,Lipase ,Polyhydroxyethyl Methacrylate ,Candida ,Dispersion polymerization ,Chromatography ,biology ,Chemistry ,Osmolar Concentration ,Temperature ,Tryptophan ,Membranes, Artificial ,Surfaces and Interfaces ,General Medicine ,Hydrogen-Ion Concentration ,Monomer ,Membrane ,Chemical engineering ,Microscopy, Electron, Scanning ,biology.protein ,Electrophoresis, Polyacrylamide Gel ,Hydrophobic and Hydrophilic Interactions ,Porosity ,Cryogels ,Chromatography, Liquid ,Biotechnology - Abstract
One-step activation, purification, and stabilization of lipase enzyme were performed by using composite hydrophobic support at low ionic strength with increased surface area during embedding process. A novel hydrophobic poly(hydroxyethylmethacrylate) [PHEMA] based, poly(glycidyl methacrylate-N-methacryloly-(L)-tryptophan) [PGMATrp] bead embedded composite cryogel membrane having specific surface area of 195 m(2)/g was used as hydrophobic matrix for adsorption of commercial Candida Rugosa lipase in a continuous system. PGMATrp embedded PHEMA cryogel membrane with 60-100 mu m pore size was obtained by dispersion polymerization of GMA and MATrp to form PGMATrp beads followed by embedding of PGMATrp to HEMA via APS and TEMED redox pair. The introduction of hydrophobic MATrp monomer into bead structure aiming to increase interaction between lipase and composite membrane was estimated using nitrogen stoichiometry of elemental analysis and found to be 239 mu mol/g of polymer. Hydophobicity increment due to embedding process was confirmed by measuring contact angle, it was found 42 degrees and 48.4 degrees for the PHEMA and PHEMA/PGMATrp composite cryogel respectively. Some parameters i.e. pH, flow-rate, protein concentration, temperature, salt type and ionic intensity were evaluated on the adsorption capacity in a continuous system. Fast protein liquid chromatography (FPLC) studies were performed for specific adsorption of lipase onto the PHEMA/PGMATrp embedded composite cryogel membrane. (C) 2015 Elsevier B.V. All rights reserved.
- Published
- 2015
25. PHEMA based composite cryogels with loaded hydrophobic beads for lysozyme purification
- Author
-
Adil Denizli and Deniz Türkmen
- Subjects
Dispersion polymerization ,Chromatography ,Comonomer ,Composite number ,Surfaces and Interfaces ,General Medicine ,Methacrylate ,Chromatography, Affinity ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Adsorption ,chemistry ,Chemical engineering ,Polymerization ,Muramidase ,Ammonium persulfate ,Physical and Theoretical Chemistry ,Lysozyme ,Hydrophobic and Hydrophilic Interactions ,Cryogels ,Polyhydroxyethyl Methacrylate ,Biotechnology - Abstract
The purpose of this study is to synthesize megaporous cryogel loaded with hydrophobic affinity beads which can be utilized for the purification of lysozyme from chicken egg-white. N-methacryloyl-( l )-tryptophan methylester (MATrp) was used as the hydrophobic ligand. In the first step, poly(glycidyl methacrylate-N-methacryloyl-( l )-tryptophan methyl-ester) [PGMATrp] beads (2.2 μm in diameter) were produced by dispersion polymerization. In the second step, the poly(2-hydroxyethyl methacrylate) (PHEMA) cryogel loaded with PGMATrp beads [PHEMA/PGMATrp composite cryogel] was polymerized initiated by N,N,N′,N′-tetramethylene diamine (TEMED) and ammonium persulfate (APS) at −12 °C. Lysozyme adsorption capacity of the PHEMA/PGMATrp composite cryogel (332.7 mg/g polymer) was improved significantly due to the loading of PGMATrp beads into the cryogel structure. The hydrophobic MATrp comonomer played a vital role in this binding mechanism. The PHEMA/PGMATrp composite cryogel could be used many times without decreasing the lysozyme adsorption amount significantly. The main advantage of the PHEMA/PGMATrp composite cryogel is the high adsorption capacity.
- Published
- 2014
26. Hemoglobin binding from human blood hemolysate with poly(glycidyl methacrylate) beads
- Author
-
Adil Denizli, Evrim Banu Altıntaş, Deniz Türkmen, and Veyis Karakoç
- Subjects
Hemoglobin binding ,Glycidyl methacrylate ,Iminodiacetic acid ,Binding, Competitive ,Chemistry Techniques, Analytical ,Hemoglobins ,symbols.namesake ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,Polymethacrylic Acids ,Polymer chemistry ,Protein purification ,Humans ,Chelation ,Physical and Theoretical Chemistry ,Molecular Structure ,Imino Acids ,Temperature ,Reproducibility of Results ,Surfaces and Interfaces ,General Medicine ,Hydrogen-Ion Concentration ,Microspheres ,Gibbs free energy ,Kinetics ,Models, Chemical ,chemistry ,Covalent bond ,Microscopy, Electron, Scanning ,symbols ,Thermodynamics ,Hemoglobin ,Algorithms ,Copper ,Chromatography, Liquid ,Protein Binding ,Biotechnology - Abstract
Metal-chelating affinity beads have attracted increasing interest in recent years for protein purification. In this study, iminodiacetic acid (IDA) was covalently attached to the poly(glycidyl methacrylate) [PGMA] beads (1.6 μm in diameter). Cu(2+) ions were chelated via IDA groups on PGMA beads for affinity binding of hemoglobin (Hb) from human blood hemolysate. The PGMA beads were characterized by scanning electron microscopy (SEM). The PGMA-Cu(2+) beads (628 μmol/g) were used in the Hb binding-elution studies. The effects of Hb concentration, pH and temperature on the binding efficiency of PGMA-Cu(2+) beads were performed in a batch system. Non-specific binding of Hb to PGMA beads in the absence of Cu(2+) ions was very low (0.39 mg/g). The maximum Hb binding was 130.3 mg/g. The equilibrium Hb binding increased with increasing temperature. The negative change in Gibbs free energy (ΔG°0) indicated that the binding of Hb on the PGMA-Cu(2+) beads was a thermodynamically favorable process. The ΔS and ΔH values were 102.2 J/mol K and -2.02 kJ/mol, respectively. Significant amount of the bound Hb (up to 95.8%) was eluted in the elution medium containing 1.0 M NaCl in 1 h. The binding followed Langmuir isotherm model with monolayer binding capacity of 80.3-135.7 mg/g. Consecutive binding-elution experiments showed that the PGMA-Cu(2+) beads can be reused almost without any loss in the Hb binding capacity. To test the efficiency of Hb depletion from blood hemolysate, eluted portion was analyzed by fast protein liquid chromatography. The depletion efficiency for Hb was above 97.5%. This study determined that the PGMA-Cu(2+) beads had a superior binding capacity for Hb compared to the other carriers within this study.
- Published
- 2011
27. Cysteine functionalized poly(hydroxyethyl methacrylate) monolith for heavy metal removal
- Author
-
Erkut Yılmaz, Sema Bektaş, Adil Denizli, Deniz Türkmen, and Lokman Uzun
- Subjects
geography ,geography.geographical_feature_category ,Chemistry ,Metal ions in aqueous solution ,Analytical chemistry ,Environmental pollution ,Metal ,Colloid and Surface Chemistry ,Adsorption ,Stability constants of complexes ,visual_art ,visual_art.visual_art_medium ,Chelation ,Qualitative inorganic analysis ,Monolith ,Nuclear chemistry - Abstract
The aim of this study was to investigate the performance of monoliths composed of hydroxyethyl methacrylate (HEMA) to which N -methacryloyl-(L)-cysteine methyl ester (MAC) was polymerized for removal of heavy metal ions. Poly(HEMA-MAC) monolith was produced by bulk polymerization. Poly(HEMA-MAC) monolith was characterized by FTIR and scanning electron microscopy (SEM). The poly(HEMA-MAC) monolith with a swelling ratio of 89%, and containing 69.4 μmol MAC/g were used in the adsorption studies. Adsorption capacity of the monolith for the metal ions, i.e., Cu 2+ , Cd 2+ , Zn 2+ , Hg 2+ , and Pb 2+ were investigated in aqueous media containing different amounts of the ions (10–750 mg/L) and at different pH values (3.0–7.0). The maximum adsorption capacities of the poly(HEMA-MAC) monolith were 68.2 mg/g for Zn 2+ , 129.2 mg/g for Cu 2+ , 245.8 mg/g for Pb 2+ , 270.2 mg/g for Hg 2+ , and 284.0 mg/g for Cd 2+ . pH significantly affected the adsorption capacity of MAC incorporated monolith. The competitive adsorption capacities were 587 μmol/g for Zn 2+ , 1646 μmol/g for Cu 2+ , 687 μmol/g for Pb 2+ , 929 μmol/g for Hg 2+ , and 1993 μmol/g for Cd 2+ . The chelating monolith exhibited the following metal ion affinity sequence on molar basis: Cd 2+ > Cu 2+ > Hg 2+ > Pb 2+ > Zn 2+ . The formation constants of MAC–metal ion complexes have been investigated applying the method of Ruzic. The calculated values of stability constants were 5.28 × 10 4 L/mol for Cd 2+ , 4.16 × 10 4 L/mol for Cu 2+ , 2.27 × 10 4 L/mol for Hg 2+ , 1.98 × 10 4 L/mol for Pb 2+ , and 1.25 × 10 4 L/mol for Zn 2+ . Stability constants were increased with increasing binding affinity. The chelating monoliths can be easily regenerated by 0.1 M HNO 3 with higher effectiveness. These features make poly(HEMA-MAC) monolith a potential adsorbent for heavy metal removal.
- Published
- 2008
28. Dye-attached magnetic poly(hydroxyethyl methacrylate) nanospheres for albumin depletion from human plasma
- Author
-
Deniz Türkmen, Öznur Gökay, Veyis Karakoç, Adil Denizli, and Müge Andaç
- Subjects
Materials science ,Biomedical Engineering ,Pharmaceutical Science ,Medicine (miscellaneous) ,(Hydroxyethyl)methacrylate ,Polymerization ,chemistry.chemical_compound ,Adsorption ,Specific surface area ,Humans ,Coloring Agents ,Dissolution ,Polyhydroxyethyl Methacrylate ,Serum Albumin ,Magnetite ,Aqueous solution ,Chromatography ,Triazines ,Albumin ,Temperature ,General Medicine ,Hydrogen-Ion Concentration ,Hemoperfusion ,chemistry ,Magnets ,Emulsions ,Nanospheres ,Biotechnology ,Nuclear chemistry - Abstract
The selective binding of albumin on dye-affinity nanospheres was combined with magnetic properties as an alternative approach for albumin depletion from human plasma. Magnetic poly(hydroxyethyl methacrylate) (mPHEMA) nanospheres were synthesized using mini-emulsion polymerization method in the presence of magnetite powder. The specific surface area of the mPHEMA nanospheres was found to be 1302 m2/g. Subsequent to Cibacron Blue F3GA (CB) immobilization onto mPHEMA nanospheres, a serial characterization processing was implemented. The quantity of immobilized CB was calculated as 800 μmol/g. Ultimately, albumin adsorption performance of the CB-attached mPHEMA nanospheres from both aqueous dissolving medium and human plasma were explored.
- Published
- 2013
29. Molecular imprinted magnetic nanoparticles for controlled delivery of mitomycin C
- Author
-
Sinan Akgöl, M. Emin Çorman, Huma Shaikh, Deniz Türkmen, Nilay Bereli, and Adil Denizli
- Subjects
Drug Carriers ,Materials science ,Scanning electron microscope ,Mitomycin ,Mitomycin C ,Biomedical Engineering ,Temperature ,Pharmaceutical Science ,Medicine (miscellaneous) ,Emulsion polymerization ,Nanoparticle ,General Medicine ,(Hydroxyethyl)methacrylate ,Hydrogen-Ion Concentration ,Molecular Imprinting ,chemistry.chemical_compound ,chemistry ,Delayed-Action Preparations ,Drug delivery ,Polymer chemistry ,Magnetic nanoparticles ,Fourier transform infrared spectroscopy ,Magnetite Nanoparticles ,Biotechnology ,Nuclear chemistry - Abstract
Controlled drug delivery system is a technique which has considerable recent potential in the fields of pharmacy and medicine. Mitomycin C is commonly used drug in the treatment of superficial bladder and breast cancers. In the present study, mitomycin C-imprinted magnetic poly(hydroxyethyl methacrylate)-based nanoparticles (MIMNs) were prepared using surfactant free emulsion polymerization for controlled delivery of mitomycin C. The MIMNs were characterized by fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, electron spin resonance, and elemental analysis. The average particle diameter of MIMNs was about 200 nm.
- Published
- 2013
30. DNA Purification by Solid Phase Extraction (SPE) Methods
- Author
-
Suleyman Asir, Deniz Türkmen, and Aykut Arif Topçu
- Subjects
DNA,DNA separation,DNA purification,SPE ,Chromatography ,Chemistry ,DNA,DNA ayrılması,DNA saflaştırılması,SPE ,Solid phase extraction ,DNA extraction - Abstract
DNA isolation/purification is a widely used procedure for molecular biology, medical studies, gene therapy and especially PCR studies which needs high quality or extremely pure nucleic acid samples. Nucleic acid separation was mainly achieved by two methods; solvent extraction and solid phase extraction SPE methods. Although solvent extraction method is the simplest method, there are some drawbacks such as toxicity, more solvent requirement, time-consuming procedure and low specificity. Nowadays, there is a wide use of solid phase matrices to extract DNA from a variety of samples. In this review article; we basically focused on SPE for DNA purification methods., D NA’nın saflaştırılması veya izole edilmesi moleküler biyoloji, tıbbi çalışmalar ve gen tedavi çalışmaları için önem taşır. Özellikle PCR çalışmaları için yüksek saflıkta DNA molekülüne ihtiyaç duyulmaktadır. Nükleik asitlerin saflaştırılmasında sırasıyla çözücü özütlemesi ve katı faz özütlemesi olmak üzere iki yöntem kulanılır. Çözücü ekstraksiyonu kolay uygulanabilir olmasına rağmen; toksisite, yüksek oranda çözücü ihtiyacı, yöntemin uzun zaman alması ve düşük özgüllüğü gibi birtakım kısıtlamalar mecvuttur. Günümüzde çeşitli örneklerden DNA’nın saflaştırılması için katı faz özütlemesi SPE yaygın olarak kullanılmaktadır. Bu çalışmada; özellikle DNA’nın saflaştırılması için SPE yönteminin uygulamaları üzerinde durulmuş ve bilimsel çalışmalar özetlenmiştir
- Published
- 2016
31. Ion-imprinted thermosensitive polymers for $Fe^ {3+}$ removal from human plasma
- Author
-
Utku, Seçil, Yılmaz, Erkut, Deniz, Türkmen, Garipcan, Bora, Say, Rıdvan, Denizli, Adil, Anadolu Üniversitesi, Fen Fakültesi, Kimya Bölümü, and Say, Rıdvan
- Subjects
Biyoloji - Abstract
Thermosensitive gels have attracted a great deal of attention for the applications of drug delivery systems, actuators, separation and removal of biological compounds and metals. Poly(N-isopropylacrylamide) (poly(NIPA)), a representative gel, has a lower critical solution temperature (LCST) in the vicinity of 32°C i.e. showing hydrophilicity and hydrophobicity in water at lower and higher temperatures, respectively. Novel adsorbents using thermosensitive gels for trapping metals were reported where poly(NIPA) was used as a thermosensitive backbone polymer. A chelating group, which interacts with heavy metals, was introduced into poly(NIPA) with a molecular imprinting technique using a specific metal as the template. Although it is emphasized that metals play important roles in biological processes and some of them are classified as essential, the toxic symptoms will manifest when a metal ion level exceeds a certain threshold level. Many symptoms of iron toxicity, for example heart attacks, diabetes, arthritis, depression and liver failure, are arised from the absorption of iron in unacceptably high concentrations because of a genetic failure or by accidental ingestion. The aim of this study is to prepare ion-imprinted polymers for the removal of iron from aqueous solutions and solutions thalassemia patient`s plasma. N-methacryloyl-(L)-cysteine (MAC) was selected as the metal complexing monomer, with the goal preparing a solid-phase which has a high selectivity for Fe3+ ions. Poly(NIPA) was used as a thermosensitive backbone polymer matrix. A chelating group [N-methacryloyl-(L)- cysteine (MAC)] which interacts with Fe3+ ions, was introduced into poly(NIPA) with a molecular imprinting technique. After removal of the Fe3+ ions, adsorption of Fe3+ ions from thalassemia patient's plasma both on the poly(NIPA-MAC) and Fe3+-imprinted poly(NIPA-MAC) particles were studied in batch-wise.
- Published
- 2008
32. Isıya duyarlı poli N-izopropilakrilamit temelli kriyojellerin SAXS çalışması
- Author
-
Veyis Karakoç, Elif Hilal Şen, Semra İde, Deniz Türkmen, Rabel Soomro, and Adil Denizli
- Subjects
N-isopropylacrylamide NIPA,thermosensitive,cryogels,Small Angle X-Ray Scattering SAXS ,N-izopropilakrilamid NIPA,ısıl duyarlı,kriyojel,Küçük Açı X-ışını Saçılması SAXS - Abstract
The purpose of this study is to observe the structural changes of the thermosensitive poly N-isopropylacrylamide- N-methacryloyl-L-histidine poly NIPA-MAH monolithic cryogel with changing temperature around lower critical solution temperature LCST of NIPA by Small Angle X-Ray Scattering SAXS . Poly NIPA-MAH cryogel was prepared by free radical cryocopolymerization of NIPA with MAH as functional comonomer and N,N- methylene-bisacrylamide MBAAm as crosslinker directly in a plastic syringe. Polymerization initiated by N,N,N,N- tetramethylene diamine TEMED and ammonium persulfate APS pair at subzero temperature in an ice bath. LCST of poly NIPA-MAH cryogel was found to be 34oC. Poly NIPA-MAH cryogel with 60–100 μm in pore diameter have a specific surface area of 42.6 m2/g polymer. This porous cryogel form provides fast temperature response comparing to conventional gels. The surface morphology and bulk structure of poly NIPA-MAH cryogel revealed with scanning electron microscopy SEM . SAXS allowed the determination of nanoalteration of poly NIPA-MAH cryogel such as pore volume, wall thickness and pore shape with changing temperature. Scattering data were analysed both native form and in water at temperature range of 300C-400C. At two different temperatures 34oC and 35oC a detailed investigation on shape of pores and pore size; which indicating a recordable change, were also carried out., B u çalışmanın amacı, NIPA’in düşük kritik çözelti sıcaklığı LCST civarındaki sıcaklığın değiştirilmesiyle ısıya duyarlı poli N-izopropilakrilamid-metakriloil-L-histidin , poli NIPA-MAH monolitik kriyojellerinin nano yapısındaki değişimleri küçük açı x-ışını saçılması SAXS yöntemi ile incelemektir. Poli NIPA-MAH kriyojeller, NIPA, MAH fonksiyonel monomeri ve N,N-metilen-bisakrilamit MBAAm çapraz bağlayıcısı kullanılarak plastik şırınga içerisinde serbest radikal kriyopolimerizasyonu ile hazırlanmıştır. Polimerizasyon buz banyosunda sıfır derecenin altında N, N, N, N-tetrametilen diamin TEMED ve amonyum persulfat APS çifti kullanılarak başlatılmıştır. Poli NIPA-MAH kriyojelinin LCST değeri 34 oC olarak bulunmuştur. Poli NIPA-MAH kriyojelleri 60-100 µm gözenek çapına ve 42.6 m2/g polimer spesifik yüzey alanına sahiptir. Sentezlenen gözenekli kriyojeller geleneksel jellerle karşılaştırıldığında sıcaklık değişimine hızlı tepki vermektedir. Poli NIPA-MAH kriyojelinin yığın yapısı ve yüzey morfolojisi taramalı elektron mikroskobu SEM kullanılarak belirlenmiştir. SAXS, poli NIPA-MAH kriyojelinin sıcaklık değişimiyle gözenek hacmi, duvar kalınlığı ve gözenek şekli gibi nano boyuttaki değişimlerin belirlenmesine imkan vermektedir. 30-40oC sıcaklık aralığında doğal form ve su içerisinde saçılma verileri incelenmiştir. Iki farklı sıcaklıkta 34oC ve 35oC gözenek boyutu ve şekli üzerinde kaydedilebilir bir değişikliği gösteren ayrıntılı bir inceleme de gerçekleştirilmiştir
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.