Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(11)
- Şahin, Engin(6)
- Taylan, Osman(5)
- Erdoğan, Yaşar(4)
- Yarımkaya, Erkan(4)
- Yılmaz, Mustafa Tahsin(4)
- Özdemir, Akın(4)
- Bayraktar, Bülent(3)
- Colak, Murat(3)
- Erbayrak, Engin(3)
- Kalay, Erbay(3)
- Çolak, Murat(3)
- Akkoyunlu, Ebubekir(2)
- Aksakal, Vecihi(2)
- Alamoudi, Mohammed(2)
- Ayazoglu, Rabil(2)
- Aydemir, Uğur(2)
- Aydin, Fatih(2)
- Bolubaid, Mohammed(2)
- Can, Zehra(2)
- Cuce, Erdem(2)
- Cuce, Pinar Mert(2)
- Gul, Volkan(2)
- Gül, Mehmet(2)
- Kara, Yakup(2)
- Karakaya, Songül(2)
- Kaya, Feridun(2)
- Kolayli, Sevgi(2)
- Kul, Murat(2)
- Ozdemir, Akin(2)
- Sağdıç, Osman(2)
- Sefalı, Abdurrahman(2)
- Takma, Çiğdem(2)
- Tekce, Emre(2)
- Töman, Ufuk(2)
- Yilmaz, Hamid(2)
- Yilmaz, Mustafa Tahsin(2)
- Öner, Erdal(2)
- Acar Soykut, Esra(1)
- Acet, Tuba(1)
Yayınlar
- MakaleYalnız künye2024Scopus SJRQ2A dual-acting aldose reductase inhibitor impedes oxidative and carbonyl stress in tissues of fructose- and streptozotocin-induced rats: comparison with antioxidant stobadine
Kaya, Alican; Ceylan, Aslı F.; Kavutcu, Mustafa; Santamaria, Abel; Šoltésová Prnová, Marta; Stefek, Milan; Karasu, Çimen
Inhibiting aldose reductase (ALR2, AR) as well as maintaining a concomitant antioxidant (AO) activity via dual-acting agents may be a rational approach to prevent cellular glucotoxicity and at least delay the progression of diabetes mellitus (DM). This study was aimed at evaluating the dual-acting AR inhibitor (ARI) cemtirestat (CMTI) on tissue oxidative stress (OS) and carbonyl stress (CS) biomarkers in rats exposed to fructose alone (F) or fructose plus streptozotocin (D; type-2 diabetic). D and F rats were either untreated or treated daily with low- or high-dose CMTI, ARI drug epalrestat (EPA) or antioxidant stobadine (STB) for 14 weeks. Malondialdehyde (MDA), glutathione S-transferase (GST), nitric oxide synthase (NOS), and catalase (CAT) were increased in the sciatic nerve of F and D. These increases were attenuated by low doses of CMTI and STB in D, but exacerbated by low-dose EPA and high-dose CMTI in F. STB and CMTI and to a lesser extent EPA improved MDA, protein-carbonyl, GST and CAT in the hearts and lungs of F and D. CMTI and STB were more effective than EPA in improving the increased MDA and protein-carbonyl levels in the kidneys of F and especially D. CMTI ameliorated renal GST inhibition in D. In the lungs, hearts, and kidneys of F and D, the GSH to GSSG ratio decreased and caspase-3 activity increased, but partially resolved with treatments. In conclusion, CMTI with ARI/AO activity may be advantageous in overcoming OS, CS, and their undesirable consequences, with low dose efficacy and limited toxicity, compared to ARI or antioxidant alone.
AtıfScopus5WoS6OpenAlex5
İncele - MakaleYalnız künye2023Scopus SJRQ3Effects of electromagnetic radiation on neurogenesis and gene expression in amniocytes
Uzun, Coşar; Erdal, Nurten; İzci Ay, Özlem; Karakaş, Ümit; Derici Yildırım, Didem; Durukan, Hüseyin; Akdag, Mahmut Berat; Erdal, Mehmet Emin
The aim of the study was to investigate the genetic effects of commonly used radiofrequency on the amniocytes of pregnant women by examining the changes in the expression of genes related to signal transduction and neurogenesis induced by electromagnetic fields of radiofrequencies of 1800 and 2100 MHz by real-time PCR. Upon exposure of the amniocytes to electromagnetic radiation of 2100 MHz at high field strength, the expression levels of genes with important functions in the Wnt signaling pathways as well as neurogenesis-related genes were increased. The findings suggest that radiofrequency at high field strengths can have genotoxic effects during pregnancy.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2023Scopus SJRQ3Isolation and characterization of yogurt starter cultures from traditional yogurts and growth kinetics of selected cultures under lab-scale fermentation
Kayacan Çakmakoğlu, Selma; Vurmaz, Melike; Bezirci, Emine; Kaya, Yasemin; Dikmen, Hilal; Göktaş, Hamza; Demirbaş, Fatmanur; Encu, Betül; Acar Soykut, Esra; Alemdar, Filiz
The development of new starter cultures is a crucial task for the food industry to meet technological requirements and traditional products are important reservoirs for new starter cultures. In this respect, this study aimed to isolate, identify, and determine the technological characteristics of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains originated from traditional yogurt samples. Genotypic discrimination of 200 isolates revealed the presence of distinct 19 S. thermophilus and 11 Lb. delbrueckii subsp. bulgaricus strains as potential starter cultures. Strain-specific properties determined the acidification capacity of the yogurt starter cultures and a higher acidification capacity was observed for S. thermophilus strains compared to Lb. delbrueckii subsp. bulgaricus strains. Proteolytic activity was found between 0.012–0.172 and 0.078–0.406 for S. thermophilus and Lb. delbrueckii subsp. bulgaricus strains, respectively. 4 of S. thermophilus and 3 of Lb. delbrueckii subsp. bulgaricus strains were found resistant to all tested bacteriophages. The antibiotic susceptibility tests of the isolates revealed that a very low antibiotic resistance was observed for the yogurt starter cultures. Finally, the growth kinetics of selected strains were determined and the maximum specific growth rate of selected S. thermophilus and Lb. delbrueckii subsp. bulgaricus was calculated as 0.527 h−1 and 0.589 h−1, respectively.
AtıfScopus8WoS10OpenAlex11İncele - MakaleAçık Erişim2023Scopus SJRQ2Determination of toxicity and radioprotective properties of bacterial and fungal eumelanin pigments
Bayram, Sinan; Aygün, Bünyamin; Karadayi, Mehmet; Alaylar, Burak; Güllüce, Medine; Karabulut, Abdulhalik
Purpose: Determination of the protective property of melanin, an organic polymer class consisting of phenolic and/or indolic compounds isolated from bacteria and fungi, against fast neutron radiation. To show that these melanin samples, which also have antioxidant and metal chelating properties, can be used as an active ingredient for a drug to be developed against neutrons used in nuclear research and medicine. Materials and methods: Bacterial and fungal media were prepared, and melanin pigments were produced and isolated. For molecular characterization of pigments, bacterial genomic DNA extraction, 16S rDNA gene amplification processes, and fungal genomic DNA extraction, ITS1, and ITS4 Gene Regions amplification were performed. The DEL assay was implemented to determine the genotoxicity properties of bacterial and fungal melanin pigments. Samples were prepared in a pad measuring 10 ml volume (60 × 15 mm) at a concentration of 0.2–1 microgram in 1% agarose gel for radiation-absorbed dose measurements. Absorption measurements were made using 241Am-Be fast neutron source and Canberra brand NP series BF3 gaseous detector to determine the neutron radiation absorption capacity of all samples. The results obtained to determine the absorption degrees of melanin samples were compared with paraffin and normal concrete, which are widely used in neutron radiation shielding studies. Results: Melanin pigments were obtained using different bacteria and fungi strains. Afterwards, the fast neutron radiation absorption capacity of these purified pigments were determined. Compared to reference samples, these pigments were found to have slightly lower radiation absorbing ability. In addition to these experiments, cytotoxicity tests were carried out using the Yeast DEL assay technique to evaluate the potential for use of these organic pigments in fields such as medicine and pharmacology. According to the results obtained from the tests, it was determined that these melanin samples did not have any toxic effects. Conclusion: It was determined that these melanin samples have the potential to be used as a radioprotective drug active substance to protect the tissues and cells of people exposed to neutron radiation after a nuclear accident or nuclear war. Giving a drug that will be developed by using these active ingredients before or after people are exposed to a radiation environment can provide great benefits.
AtıfScopus12WoS12OpenAlex17İncele - MakaleAçık Erişim2023Scopus SJRQ2Dynamic response of polypropylene honeycomb/polystyrene foam core sandwich composite panels: Experimental and numerical analysis
Caliskan, Umut; Demirbas, Munise Didem; Erdogan, Omer
In this study, dynamically loaded sandwich panels with two different core materials and face sheets made of aluminum alloys (6061-T6) were investigated experimentally and numerically under low-velocity impact. Polypropylene, PP (C3H6)n honeycomb and extruded polystyrene foam, XPS (C8H8)n were preferred as core material. By using the contact force and kinetic energy changes, which were the impact test results of the sandwich panels, the contact and impact resistance was examined. As a result of the tests, damaged regions and permanent central displacement were determined and energy absorption capabilities were demonstrated for two different structures. The results obtained were compared with the results obtained by the open finite element method. In this study, it was shown that the face-sheet thickness of sandwich panels was an important parameter affecting the impact behavior. The behavior of the core material when the face-sheet loses its rigidity was investigated and it was found that polystyrene foam was more effective in preventing impact damage. However, it was found that using the PP honeycomb or XPS was affected the impact behavior in different points.
AtıfScopus10WoS10OpenAlex12İncele - MakaleAçık Erişim2023Scopus SJRQ2Suberosin Alleviates Sepsis-Induced Lung Injury in A Rat Model of Cecal Ligation and Puncture
Karabulut Uzunçakmak, Sevgi; Halıcı, Zekai; Karakaya, Songül; Kutlu, Zerrin; Sağlam, Yavuz Selim; Bolat, İsmail; Aydın, Pelin; Kılıç, Ceyda Sibel
Background/aims: Sepsis is one of the major problems encountered in intensive care units, causing organ damage and increasing mortality. Suberosin (SBR) is a type of coumarin with antioxidant and anti-inflammatory activities. The goal of this study is to explore the protective effects of SBR on the lungs in a rat model of sepsis. Methods: Male Wistar rats were utilized in this study. A cecal ligation and puncture (CLP) model was applied to induce sepsis. Rats were separated into six groups with nine animals in each group, including healthy control, SBR, CLP, and CLP + SBR (5, 10, and 20 mg/kg) groups. Superoxide dismutase (SOD), glutathione (GSH) enzyme activities, and malondialdehyde (MDA) level were measured via enzyme-linked immunosorbent assay (ELISA). The messenger RNA (mRNA) expressions of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) were evaluated by real-time polymerase chain reaction (RT-PCR). Histopathological changes in the lungs were investigated with hematoxylin and eosin (H&E). Results: MDA levels and GSH and SOD enzyme activities were negatively affected in the CLP group, but SBR treatment ameliorated these oxidative stress parameters in the SBR1-3 groups (p< 0.05). The mRNA expressions of TNF-α and IL-1β were increased in the CLP group, and SBR treatment decreased those expression levels in a dose-dependent manner (p < 0.05). Organ damage and necrosis were seen in the CLP group and were alleviated in the SBR3 group. Immunohistochemical (IHC) analysis of lung tissues demonstrated decreased TNF-α and IL-1β immunopositivity in the SBR1-3 groups (p< 0.05). Conclusions: SBR ameliorated sepsis-related lung injury in a dose-dependent manner. This compound has significant potential as a future agent in the treatment of sepsis.
AtıfScopus15WoS11OpenAlex15İncele - MakaleAçık Erişim2023Scopus SJRQ2Investigation of organic and inorganic matters removal from tannery wastewater using iron plate electrode by electrocoagulation process
Bingül, Züleyha; Irdemez, Şahset; Kul, Sinan; Ekmekyapar Torun, Fatma; Demircioğlu, Nuhi
In this study, COD, turbidity, total nitrogen, phosphate, sulphate, oil-grease and chromium removals from wastewaters taken from a local tannery using the electrocoagulation process were examined and the most suitable parameters for the electrocoagulation system were tried to be determined. Soluble iron plate electrodes were used as electrodes in the experiments. As a result of the studies carried out, the most suitable initial pH in uncontrolled pH was determined as pH = 4 and for controlled pH as pH = 5. In studies, the most suitable current density for iron electrodes was determined as 1.2 mA cm−2. Even if the increase in current density increased the amount of dissolved Fe, it negatively affected the removal efficiency. In addition, the turbidity of the wastewater was removed in 30 minutes, phosphate in 20 minutes and chromium in 15 minutes by 100%. During 60 minutes of operation, while 62.91% of TN, 87.8% of oil-grease were removed, sulphate was removed at the rate of 54.78%. In the studies, 1st and 2nd order kinetic equations for COD removal were examined and it was determined that removal kinetic is more suitable for 2nd order kinetics.
AtıfScopus7WoS4İncele - MakaleAçık Erişim2023Scopus SJRQ3Exploring Turkish parents’ lived experiences on online science lessons of their children with mild intellectual disability amid the COVID-19 pandemic
Yarımkaya, Derya; Töman, Ufuk
Background: The purpose of this qualitative study was to explore Turkish parents’ lived experiences on online science lessons of their children with mild intellectual disability amid COVID-19 pandemic. Method: This study used the phenomenological qualitative research design. Participants in this study were 16 parents, who have children with mild intellectual disability and participated in one-on-one semi-structured phone calls. Interview data were thematically analyzed. Result: Five overarching themes were found: (1) parents’ general experiences on online science lessons, (2) advantages of online science lessons, (3) disadvantages of online science lessons, (4) barriers in online science lessons, and (5) parents’ recommendations for online science lessons. Conclusion: The results revealed that the majority of parents agreed on the school closure policy due to the COVID-19 pandemic, but were not satisfied with the online science lessons, and focused on the disadvantages of online science lessons for their children with mild intellectual disability.
AtıfScopus6WoS10OpenAlex14İncele - MakaleAçık Erişim2023Scopus SJRQ1The effect of waste material generated during paper production on the rheological and structural features of asphalt binder
Yilmaz, Bahadir; Ugurlu, Nuray
In this study, the performance properties of magnesium lignosulfonate, an organic waste material produced during paper production from wood, on asphalt binder were investigated. The modification was carried out by adding magnesium lignosulfonate (MLS) at 2%, 4%, 6%, and 8% by weight to the asphalt with B50/70 penetration grade. The morphological structure, modification mechanism, and thermal decomposition temperatures of the modified asphalt binders formed by adding the MLS to the asphalt were determined by a Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and Thermogravimetry-Differential Thermal Analysis (TG/DTG), respectively. The physical and rheological properties of the material were determined by penetration, softening point, Rolling Thin Film Oven Test (RTFOT), Dynamic Shear Rheometer (DSR), and Rotational Viscometer (RV) experiments conducted in a laboratory. The experimental results showed that the organic-based waste additive increases the asphalt consistency, rutting, and short-term aging resistance, and decreases the temperature sensitivity.
AtıfScopus6WoS7OpenAlex7İncele - MakaleAçık Erişim2023Scopus SJRQ3Optimization of asymmetric bioreduction conditions of 1-(thiophen-2-yl)ethanone by Weissella cibaria N9 using a desirability function-embedded face-centered optimization model
Bolubaid, Mohammed; Özdemir, Akın; Dertli, Enes; Alamoudi, Mohammed; Taylan, Osman; Karaboğa, Derviş; Yılmaz, Mustafa Tahsin; Şahin, Engin
Prochiral ketones can be effectively bio-reduced to chiral secondary alcohols by whole-cell biocatalysts, which are possible useful precursors to synthesize physiologically active chemicals and natural products. When whole-cell biocatalysts strains are used, bioreduction process can be influenced by various cultural factors, and it is vital to optimize these factors that affect selectivity, conversion rate, and yield. In this study, Weissella cibaria N9 was used as whole-cell biocatalyst for bioreduction of 1-(thiophen-2-yl)ethanone, and cultural design factors were optimized using a desirability function-embedded face-centered optimization model. For this, effects of pH (4.5–5.5–6.5, x 1), (2) temperature (25–30–35 °C, x 2), (3) incubation period (24–48–72 h, x 3), and (4) agitation speed (100–150–200 rpm, x 4) on two response variables; (1) ee (%) and (2) cr (%) were tested. Next, desirability function-embedded face-centered optimization model revealed that a pH of 6.43, a temperature of 26.04 °C, an incubation period of 52.41 h, and an agitation speed of 150 rpm were the optimum levels and the estimated ee and cr responses were 99.31% and 98.16%, respectively. Importantly, the actual experimental ee and cr responses were similar to the estimated values indicating the capability of the offered desirability function-embedded face-centered optimization model when using the optimum cultural conditions.
AtıfScopus1WoS1OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ2Investigations of low-velocity impact behaviour of single-lap joints having dissimilar hybrid composite adherends through cohesive zone model approach
Erbayrak, Engin
The low-velocity impact behavior of single-lap joints was investigated in this study. In single-lap joints, woven carbon fiber reinforced epoxy (CFRE) and plain woven glass fiber reinforced epoxy (GFRE) laminates as well as a hybrid composite laminate (HCGFRE), which is formed by stacking carbon and glass composite laminates, are used as adherends. Araldite 2011 and Araldite 138 M/HV998 epoxy adhesives were used with different mechanical properties for joining similar and dissimilar composite adherends. Low-velocity impact tests were carried out with 40 J impact energy. Reaction force-time and impact energy-time graphs were obtained from the experimental study as impact response. In numerical analyses, the damage approach of composite adherend was modeled using composite stress-based failure model (Mat 59) and adhesives were modeled utilizing a mixed-mode cohesive zone model (Mat 138) that existed in LS-DYNA explicit finite element software. It was seen that the numerical results indicated a similar tendency with the experimental results due to the modeling of the adhesives using the proper cohesive zone model, the application of correct boundary conditions, and the selection of the correct contact type.
AtıfScopus9WoS9OpenAlex10İncele - MakaleAçık Erişim2022Scopus SJRQ3Optimization of lactose derivative hetero-oligosaccharides production using whey as the acceptor molecule by an active glucansucrase
Kabli, Mohammad; İspirli, Hümeyra; Balubaid, Mohammed; Taylan, Osman; Yılmaz, Mustafa Tahsin; Dertli, Enes
Glucansucrases are capable of synthesis of distinct oligosaccharides using different acceptor molecules and in this study lactose derivative hetero-oligosaccharides were shown to be produced by an active glucansucrase in its acceptor reaction with sucrose and whey as the donor-acceptor molecules, respectively. Following the monitoring of the reaction products by TLC analysis, the effects of reaction parameters in terms of enzyme concentration, sucrose/whey ratio and reaction temperature on final oligosaccharide yields (OY) were optimized by Response Surface Methodology (RSM). Results indicated that increment of enzyme concentration and reaction temperature decreased the OY in a particular reaction time whereas the OY increased with the increment of sucrose/whey ratio in the acceptor reactions of glucansucrase E81 with whey as the acceptor molecule. A low level of glucansucrase E81 concentration was sufficient to obtain the highest OY in the tested conditions. These findings demonstrated the importance of the optimisation of the reaction parameters for the acceptor reactions of the glucansucrases.
AtıfScopus2WoS4OpenAlex6İncele - MakaleYalnız künye2022Scopus SJRQ2Investigation of the effect of the addition of grain refiner and modifier addition on wear properties in sand and permanent mould casting of A357 and A380 aluminium alloys
Çolak, Murat; Arslan, İbrahim
The aim of this study is to improve the tribological behaviour of aluminium alloys by using grain refiner and modifier. The effects of Al5Ti1B grain refiner and Al10Sr modifier additives on friction and wear properties on A380, A357 alloys produced by pouring sand andpermanent mould casting were investigated. Abrasion tests were carried out under dry conditions against St1040 steel disc using a pin-disk system with 20 N load and 1.0 m/s sliding speed. It was determined that grain refiner and modifier additives decrease the friction coefficient and increase the wear resistance. It was determined that the samples produced by permanent mould casting method decreased the friction resistance by 9% and the abrasion resistance increased by 40% compared to the samples produced in sand mould. The lowest wear rate was obtained in A380 alloy with TiB and Sr added with a value of 4.87 × 10–11 m2/N.
AtıfScopus12WoS10OpenAlex13İncele - MakaleAçık Erişim2022Scopus SJRQ3Production of enantiomerically enriched chiral carbinols using whole-cell biocatalyst
Baydaş, Yasemin; Kalay, Erbay; Şahin, Engin
Biocatalytic asymmetric reduction of ketone is an efficient method for the production of chiral carbinols. The study indicates selective bioreduction of different ketones (1–8) to their respective (R)-alcohols (1a–8a) in low to high selectivity (0- >99%) with good yields (11–96%). In this work, whole-cell of Lactobacillus kefiri P2 catalysed enantioselective reduction of various prochiral ketones was investigated. (R)-4-Phenyl-2-butanol 2a, which is used as a precursor to antihypertensive agents and spasmolytics (anti-epileptic agents), was obtained using L kefiri P2 in 99% conversion and 91% enantiomeric excess (ee). Moreover, bioreduction of 2-methyl-1-phenylpropan-1-one substrate 8, containing a branched alkyl chain and difficult to asymmetric reduction with chemical catalysts as an enantioselective, to (R)-2-methyl-1-phenylpropan-1-ol (8a) in enantiomerically pure form was carried out in excellent yield (96%). The gram-scale production was carried out, and 9.70 g of (R)-2-methyl-1-phenylpropan-1-ol (8a) in enantiomerically pure form was obtained in 96% yield. Also especially, the yield and gram scale of (R)-2-methyl-1-phenylpropan-1-ol (8a) synthesised through catalytic asymmetric reduction using the biocatalyst was the highest report so far. The efficiency of L kefiri P2 for the conversion of the substrates and ee of products were markedly influenced by the steric factors of the substrates. This is a cheap, clean and eco-friendly process for production of chiral carbinols compared to chemical processes.
AtıfScopus5WoS5OpenAlex6İncele - MakaleYalnız künye2022Scopus SJRQ2MODELLING AND VALIDATION OF EFFECT OF BINDER TYPE ON FEEDING BEHAVIOUR OF SPHEROIDAL GRAPHITE CAST IRON
Çolak, Murat; Şekerden, Mete
In the casting method, it is crucial to properly make the moulding design to produce sound parts. Volumetric change, especially during the solidification of spheroidal graphite cast irons, may show different behaviour compared to steel and aluminium castings. In this study, castings were carried out with single and double feeders with varying casting parameters of green sand and resin mould sand containing different cross-sectional thicknesses. Depending on the chemical composition, mould rigidity and inoculation efficiency, and the importance of the feeder path was evaluated by experimental and modelling techniques. Consequently, it was observed that the risk of shrinkage in resin moulds is less than in green sand castings in the same moulding design. In addition, it has been found that the number of feeders and neck connection is an important parameter in pore formation.
AtıfScopus2OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ3Performance Analysis of Buck-Boost and SEPIC Converter for Commutation Torque Ripple Minimization in BLDC Motors
Çorapsız, Muhammed Reşit; Kahveci, Hakan
This paper discusses comparative analysis of Buck-Boost and SEPIC (Single Ended Primary Inductance) converters used in DC link voltage control technique to reduce torque ripple in Brushless Direct Current Motors (BLDCM). The aim of this study is to prove the efficiency of the aforementioned two converters, which have been adopted in many studies to reduce torque ripples caused by commutation, on the same motor parameters. Although BLDCM has many advantages, ripples in the generated torque have limited the use of these motors in applications requiring precise speed and torque. In this study, BLDCM was analyzed exhaustive mathematically and electrically and the problem that caused commutation torque ripples was explained in detail. The DC link voltage control has been proposed to suppressing torque ripples in the BLDCM. In addition, the link voltages required for reducing the torque ripples were obtained separately via both the Buck-Boost and the SEPIC converters. These converter topologies are examined under certain speed and torque conditions and the results were compared. When the results are evaluated together, it was observed that both converters performed the very closely performance each other. However, the Buck-Boost converter produced the desired voltage levels with less oscillation than the SEPIC converter.
AtıfScopus5WoS2OpenAlex3İncele - MakaleYalnız künye2022Scopus SJRQ3Biocatalytic asymmetric synthesis of (S)-1-indanol using Lactobacillus paracasei BD71
Kalay, Erbay; Dertli, Enes; Şahin, Engin
Enantiopure benzo-fused cyclic alcohols have been used as a building block of a drug for Parkinson’s disease. Biocatalytic reduction of ketones is one of the most promising and significant routes to prepare optically active alcohols. In this study, the reductive capacity of seven lactic acid bacteria (LAB) strains were investigated as whole-cell biocatalyst in the enantioselective reduction of 1-indanone (1). Lactobacillus paracasei BD71 was found to have the best reductive capacity. Effects of different parameters such as pH, incubation time, agitation speed and temperature, on enantiomeric excess (ee) and conversion were investigated in a bioconversion. (S)-1-indanol ((S)-2) could be used as precursor for the synthesis of rasagiline mesylate TVP1012 for the therapy of Parkinson’s illness. It was produced in gram-scale (5.24 g), high yield (93%) and enantiomerically pure form using L. paracasei BD71 whole-cell biocatalysts. Also, to our knowledge, this is the first report on production of (S)-2 using whole-cell catalyst in enantiopure form, excellent yield, conversion and gram scale. This is a cheap, clean and eco-friendly process for production of (S)-2 compared to chemical processes.
AtıfScopus6WoS6OpenAlex6İncele - MakaleYalnız künye2022Scopus SJRQ3Optimization of asymmetric reduction conditions of 1-(benzo [d] [1,3] dioxol-5-yl) ethanone by Lactobacillus fermentum P1 using D-optimal experimental design-based model
Özdemir, Akın; Dertli, Enes; Şahin, Engin
The biocatalytic asymmetric reduction of prochiral ketones is a significant transformation in organic chemistry as chiral carbinols are biologically active molecules and may be used as precursors of many drugs. In this study, the bioreduction of 1-(benzo [d] [1,3] dioxol-5-yl) ethanone for the production of enantiomerically pure (S)-1-(1,3-benzodioxal-5-yl) ethanol was investigated using freeze-dried whole-cell of Lactobacillus fermentum P1 and the reduction conditions was optimized with a D-optimal experimental design-based optimization methodology. This is the first study using this optimization methodology in a biocatalytic asymmetric reduction. Using D-optimal experimental design-based optimization, optimum reaction conditions were predicted as pH 6.20, temperature 30 °C, incubation time 30 h, and agitation speed 193 rpm. For these operating conditions, it was estimated that the product could be obtained with 94% enantiomeric excess (ee) and 95% conversion rate (cr). Besides, the actual ee and cr were found to be 99% tested under optimized reaction conditions. These findings demonstrated that L. fermentum P1 as an effective biocatalyst to obtain (S)-1-(1,3-benzodioxal-5-yl) ethanol and with the D-optimal experimental design-based optimization, this product could be obtained with the 99% ee and 99% cr. Finally, the proposed mathematical optimization technique showed the applicability of the obtained results for asymmetric reduction reactions.
AtıfScopus6WoS6OpenAlex7İncele - MakaleYalnız künye2022Scopus SJRQ2A study on the effects of nanostructure reinforcement on the failure load in adhesively bonded joints after the subjected to fully reversed fatigue load
Akpinar, Salih; Demir, Kübra; Gavgali, Esma; Yetim, Ali Fatih
Today, adhesively bonded joints are frequently used in the space and aviation industries. Joints used in these sectors are generally subject to dynamic loads due to environmental factors. This study experimentally and numerically investigated the static tensile loads of adhesively bonded joints after fully reversed (combination of tensile and compressive) fatigue loading where nanoadhesives–obtained by adding carbon nanostructures into aerospace grade structural adhesive–were used to bond the joints. Single lap joint specimens were produced using a nanocomposite adhesive obtained by adding 1 wt. % graphene, 1 wt. % carbon nanotubes-COOH and 1 wt. % fullerene C60 nanostructures to a DP460 structural adhesive. AA2024-T3 aluminum alloy and carbon fiber-reinforced composites (CFRCs) with a plain weave fabric (0/90°) were used as adherend materials. First, static tensile tests were applied to these joints to obtain their failure loads and then fully reversed sinusoidal fatigue tests were applied under a constant load amplitude, a frequency of 20 Hz and a load ratio of R = −1. Considering the failure loads obtained from the static tensile tests, 106 fully reversed fatigue loading cycles were applied–which was accepted as an infinite life–at 400 N, 800 N and 1200 N load levels. The static tensile failure loads and energy values absorbed of these joints were obtained and the change in the failure loads and energy values absorbed of the joints subjected to fatigue was investigated. The static failure loads of aluminum joints bonded with nanoadhesive and subjected to fully reversed fatigue loading increased by approximately 5% to 17%, depending on the nanostructure type added to the adhesive. Moreover, it was observed that there was an increase in loading of approximately 3% to 20% for the nanostructure reinforced joints obtained by using CFRCs with [0/90]6 stacking sequence.
AtıfScopus24WoS26OpenAlex28İncele - MakaleAçık Erişim2021Scopus SJRQ3Does compliance with the preventive health behaviours against COVID-19 mitigate the effects of depression, anxiety and stress? (¿Cumplir con los comportamientos preventivos de salud contra el COVID-19 reduce los efectos de la depresión, la ansiedad y el estrés?)
Aydin, Fatih; Kaya, Feridun
In the present study, the aim was to investigate the associations between compliance with preventive health behaviours, depression, anxiety and stress. 478 adults living in Turkey voluntarily filled out the online survey, which comprised demographic questions, Measure of Compliance with Preventive Health Behaviours against COVID-19, and Depression Anxiety Stress Scales, between 24–31 March 2020: during the initial phase of the COVID-19 pandemic in Turkey. Results revealed that compliance with preventive health behaviours has negative associations with depression, anxiety and stress. Adults’ compliance with the recommended preventive health behaviours accounted for 14% variance in depression, 9% variance in anxiety and 10% variance in stress. The evidence might indicate that compliance with preventive health behaviours may protect people psychologically against the burden created by the novel COVID-19 pandemic.
AtıfScopus6WoS7OpenAlex6İncele