Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Acet, Tuba(4)
- Aydınçakır, Emre(4)
- Kaygusuz, Abdullah(4)
- Sukuroglu, Ebru Emine(4)
- Baltacı, Cemalettin(3)
- Dessureault, Sean(3)
- Kankal, Murat(3)
- Karpuz, Ömer(3)
- Kurt, Kemal(3)
- Totik, Yasar(3)
- Yücel, Cem(3)
- Şan, Murat(3)
- Aksüt, Yavuz Selim(2)
- Akçay, Fatma(2)
- Ar, Ilker Murat(2)
- Cicerali, Derya(2)
- Duran, Celal(2)
- Efeoglu, Ihsan(2)
- Erol, Ismail(2)
- Günen, Mehmet Akif(2)
- Gürdal Limon, Elif(2)
- Jeong, Youn-Joong(2)
- Kahraman, M. Mustafa(2)
- Kurnaz, Muammer(2)
- Kurt, Pınar(2)
- Limon, Onur(2)
- Ozdes, Duygu(2)
- Oztel, Ahmet(2)
- Peker, Iskender(2)
- Rogers, W. Pratt(2)
- Saydam Eker, Çiğdem(2)
- Sukuroglu, E.E.(2)
- Sukuroglu, Suleyman(2)
- Totik, Y.(2)
- Vural, Alaaddin(2)
- Yetgin, Şükrü(2)
- Yi, Keewook(2)
- Yılmaz, Hacı Ömer(2)
- Çullu, Mustafa(2)
- İlyasoğlu, Huri(2)
Yayınlar
- MakaleAçık Erişim2024The impact of the Ukraine war on Russian military capabilities in the Arctic
Limon, Onur; Gürdal Limon, Elif
This study examines the impact of the two-year occupation of Ukraine on Russia’s military capabilities in the Arctic and analyzes the strengths and weaknesses of Russia’s military capacity in this region. Using a methodology based on document analysis and SWOT analysis, the study aims to unravel the intricate interplay between the Ukraine conflict and Russia’s military aspirations in the Arctic and thereby improve our understanding of the military implications of these developments. The results of the study highlight a remarkable imbalance in Russia’s military capabilities in the vast Arctic region, which stretches across the western, central, and eastern sectors. The ongoing conflict in Ukraine is acting as a catalyst, forcing Russia to strengthen its conventional forces and improve its military readiness in the immediate future. As a result, there is a discernible inclination to prioritize nuclear capabilities as part of Russia’s strategic calculus in the Arctic region.
- MakaleYalnız künye2023Effect of Brewing Conditions on Sensorial and Antioxidant Properties of Linden Tea
Ilyasoğlu, Huri; Arpa Zemzemoğlu, Tuba Eda
The aim of this study was to investigate the effects of brewing conditions (infusion time and temperature) on the sensorial and antioxidant properties of linden tea. The sensorial properties (color, odor, taste, and overall acceptability), total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and ferric reducing antioxidant power (FRAP) of the tea samples were analyzed. A two-factor and three-level central composite design was applied for response surface methodology (RSM) to assess the effects of the independent variables on the responses. Our findings revealed that the best combination of temperature and time was 85–95°C and 8–10 min for the linden tea.
- MakaleYalnız künye2023Reply to discussion of “Innovative approaches to the trend assessment of streamflows in the Eastern Black Sea basin, Turkey”*
Akçay, Fatma; Kankal, Murat; Şan, Murat
In this reply we thank the authors for their comments on our article “Innovative approaches to trend assessment of streamflows in the Eastern Black Sea basin, Turkey.” They stated that the trend slope calculations in our study are incorrect. A response to the discussion on this topic offered.
- MakaleAçık Erişim2023Magmatic evolution of the Calc-alkaline Middle Jurassic igneous rocks in the eastern pontides, NE Turkey: insights from geochemistry, whole-rock Sr-Nd-Pb, in situ zircon Lu-Hf isotopes, and U-Pb geochronology
Aydınçakır, Emre; Yücel, Cem; Kaygusuz, Abdullah; Bilici, Özgür; Yi, Keewook; Jeong, Youn-Joong; Güloğlu, Z. Samet
The Eastern Pontides in NE Turkey hosts a very limited number of plutonic rocks from the Jurassic period. Here we submit new geochemical, Sr-Nd-Pb and zircon Lu-Hf isotope data, and zircon U-Pb ages for plutonic rocks in this region. Zircon U-Pb dating for the Alemdar and Işıkdere plutons yielded an age of 175–170 Ma (Middle Jurassic). The Alemdar and Işıkdere plutons have I-type, medium to high-K calc-alkaline series, and metaluminous to slightly peraluminous characteristics. On PM-normalized diagrams, the plutons are enriched in large-ion lithophile elements (LILEs) with pronounced depletion of high field strength elements (HFSEs, Ta, Nb, Ti). Chondrite-normalized plots for the plutons show variable enrichment in light rare earth elements (LREEs) with depletion of heavy rare earth elements (HREEs). The rocks of the Alemdar Pluton have homogeneous ISr values (0.70585 to 0.70673), low εNd(i) values (−3.9 to −1.6), pozitif εHf(i) values (+3.3 to +9.1), and Hf single-stage model ages (563–712 Ma), whereas those of Işıkdere have high ISr values (0.70666 to 0.70673), low εNd(i) values (−3.9 to −3.8), εHf(i) values (−3.1 to +1.1), and Hf single-stage model ages (791–969 Ma). These values imply that they have different sources. These results suggest that the magma of the Alemdar was formed by the partial melting of a relatively depleted lithospheric mantle wedge interaction of the OIB-like melts, while those of Işıkdere have derived from the partial melting of an enriched mantle metasomatized by slab-derived sediments and then modified by fractional crystallization and crustal contamination in crustal magma chambers. Considering the available data, we conclude that the studied plutons were related to extensional tectonic events during the Middle Jurassic in response to the roll-back of the Paleotethys oceanic slab in the final stage of oceanic closure. These rocks are an example of the formation of deep subduction products following Early Jurassic subduction.
- MakaleYalnız künye2023Multi-Scenario Analysis of Rockfall Hazard for a Historical Vaulted Masonry Building in Sumela Monastery
Nasery, Mohammad Manzoor; Cosgun, Suleyman Istemihan; Temel, Bayram Ali
Sumela Monastery located in the northeast city of Trabzon is one of the most-visited touristic places in Turkey. As it is located in a mountainous area, rockfall hazards have become a crucial problem that the Monastery complex faces, especially in the last decade. Due to several rockfall cases, the monastery was closed for visitors in 2015 to take preventative measures. The current study examines the whole stages assessing and eliminating rockfall hazards that a historical Vaulted masonry building in the Sumela Monastery is exposed to. First of all, field studies were conducted to determine the kind and type of rockfall hazard. For this purpose, the regional geology of the area was evaluated and due to the inaccessibility of the region, industrial climbers were recruited to climb the slope above the Historical Vaulted building to determine the locations, dimensions, and risk level of the risky blocks that threatened the building. After that, the terrain of the risky area was modeled with Unmanned Aerial Vehicle (UAV) using the digital photogrammetry method. In the last step of the field studies, samples were taken to determine the mechanical and physical properties of the rocks and several laboratory tests were conducted. In the second part of the study, probabilistic analyses of 2400 rockfall simulations with eight different trajectories were conducted to calculate the maximum run-out distance, velocity, kinetic energy, and bounce heights of falling blocks. In the third part, to evaluate the damage status on the vaulted building, six different possible rockfall scenarios determined by the rockfall analysis were simulated using the Finite Element Method. After determining the rock block size that would not cause significant damage to the building, the cleaning and controlled removal method of the risky blocks was determined. In the last stage, controlled crushing and removing practices for risky rock blocks were carried out and the building was restored. Consequently, the rockfall hazard for the historical Vaulted building was eliminated and the monastery complex opened for visitors in 2021.
- MakaleAçık Erişim2023Modelling some stand parameters using Landsat 8 OLI and Sentinel-2 satellite images by machine learning techniques: a case study in Türkiye
Bulut, Sinan; Günlü, Alkan; Çakır, Günay
Remote sensing technologies have been extensively used in forest management in predicting stand parameters. The goal of this study is to use Landsat 8 and Sentinel-2 satellite images to estimate stand volume, basal area, number of trees, mean diameter, and top height. 180 temporary sample plots were taken in pure Crimean pine stands with varied structure. Reflectance, vegetation indices, and eight texture values were generated from Landsat 8 and Sentinel-2 satellite images. The stand parameters were modelled with the remotely sensed data using multiple linear regression, support vector machine, and deep learning techniques. The results showed that the support vector machine technique provided the highest level of model performance with 45° orientation for number of trees (R2 = 0.98, RMSE%=5.97) and 90° orientation for basal area (R2=0.91, RMSE%=15.22). The results indicated that the texture values presented better results than the reflectance and the vegetation indices in estimating the stand parameters.
- MakaleYalnız künye2023Effect of detector crystal size on Compton suppression factors
Kaya, Selim; Çelik, Necati; Gök, Abdulkadir; Çevik, Uğur
The geometrical parameters which affect the suppression factor for an HPGe (High Purity Germanium)-NaI Compton suppression spectrometer were studied by a Monte Carlo simulation with the EGS4 system. The spectrums were crated for 5 energy values ranging from 200 keV to 2 MeV. Compton suppression factors (CSFs), the parameters characterizing the system performance, were calculated for different HPGe crystal parameters. It was observed that to obtain better Compton suppressed factors, a laboratory must choose as small HPGe crystal as possible for energy values up to 400 keV. However, for higher energies up to 2 MeV, larger HPGe crystals provide better Compton suppression systems. These findings suggest that the choice of HPGe crystal size can significantly impact the performance of a Compton suppression spectrometer and should be carefully considered in its design and optimization.
- MakaleAçık Erişim2023Investigating the EKC hypothesis with nanotechnology, renewable energy consumption, economic growth and ecological footprint in G7 countries: panel data analyses with structural breaks
Aydin, Mucahit; Koc, Pınar; Sahpaz, Kadriye Izgi
This study investigates the relationship between nanotechnological innovations, renewable energy consumption, economic growth, and ecological footprint for G7 countries within the framework of the Environmental Kuznets Curve (EKC) hypothesis. The study employs panel cointegration tests with structural breaks from 1990–2018. Nanotechnology is expected to reduce environmental degradation by increasing renewable energy consumption and energy saving. In this context, nanotechnological innovations are an essential tool for sustainable development. However, the literature also emphasizes that nanoparticle emissions from nanotechnology can negatively impact human and environmental health in the long term, and these need to be analyzed. In this context, this study is the first to empirically examine the relationship between nanotechnological innovations, renewable energy consumption, economic growth, and ecological footprint within the framework of the EKC hypothesis. The outcomes affirm that all variables are integrated with the long term. The results show that the EKC hypothesis is valid only in the USA. Nanotechnological innovations have a reducing effect on environmental degradation in the USA, whereas; they have an increasing impact on environmental degradation in Italy and the United Kingdom. Renewable energy consumption enhances environmental quality in Italy, Japan, the United Kingdom, and the USA. Based on these empirical findings, the government should pioneer to development of new the lowest nanoparticle-emitting nanotechnologies. And that way, it will be possible to encourage energy savings and renewable energy consumption more safely, and the effectiveness of sustainable development policies will increase.
- MakaleYalnız künye2023Application of Magnetic Fe3O4 Alnus glutinosa Sawdust Biochar/SiO2/CTAB as a New Sorbent for Magnetic Solid Phase Extraction of Heavy Metals from Fruit and Waters Samples
Duran, Celal; Ozdes, Duygu
The coating of magnetic Fe3O4 Alnus glutinosa sawdust biochar with SiO2 and further functionalising by cetyltrimethyl ammonium bromide (CTAB), a cationic surfactant, was described for the first time in the current paper. The magnetic Fe3O4 Alnus glutinosa sawdust biochar/SiO2/CTAB(MAGBC/SiO2/CTAB) was implemented to separate and preconcentrate the Cu2+, Cd2+, and Pb2+ions efficiently in waters and a number of fruit samples by solid-phase extraction (SPE) method. Adsorbent characterisation was realised by fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Fundamental factors affecting the extraction yield of the analyte ions including solution pH, adsorbent amount, sample volume and desorption contact time were fully researched and optimised as 8.0, 0.25 g, 500 mL and 60 min, respectively, and the eluent was specified as 5.0 mL of 0.1 M of HCl solution. The adsorption equilibrium eventuated after 15 min of contact time and it was noticed that the chemisorption mechanism was dominant upon the analyte ions adsorption. The limits of detection (LOD) were calculated as 0.24, 0.62 and 1.55 µg L−1 and the limits of quantitation (LOQ) were determined as 0.81, 2.08, and 5.17 µg L−1 for Cu2+, Cd2+, and Pb2+ ions, respectively. The relative recoveries (RR%) were in the ranges of 93.3–103.4%, 92.5–102.8%, and 91.8–101.9% for Cu2+, Cd2+, and Pb2+ ions, respectively, while the relative standard deviations (RSD%) were obtained lower than 4.0% (n = 10) by applying the method at optimised conditions. The maximum adsorption capacities of MAGBC/SiO2/CTAB were obtained as 123.7, 80.0 and 118.5 mg g−1for Cu2+, Cd2+, and Pb2+ions, respectively. Consequently, the developed new, simple, rapid, sensitive, and economical SPE method based on MAGBC/SiO2/CTAB was successfully implemented to waters and some of the fruit samples to determine the Cu2+, Cd2+, and Pb2+ions simultaneously.
- MakaleYalnız künye2022Development of Homemade Hazelnut Milk-based Beverage
Aysu, Şühedanur; Akıl, Fatoş; Çevik, Edanur; Kılıç, Mustafa Emin; İlyasoğlu, Huri
A homemade hazelnut milk-based beverage was prepared from hazelnut milk with raisins. The proximate composition, physicochemical and sensorial properties, total phenolic content (TPC), antioxidant activity, and fatty acid compositions of the beverage samples were determined. The properties of the three different preparations of homemade hazelnut milk with raisins (1%, 3%, and 5%) were compared with the control sample without raisins. The main macronutrient was fat (6.3‒7.3%) in the hazelnut milk beverage followed by carbohydrate (3‒3.5%) and protein (2.2‒2.5%). The addition of raisins to the beverage formulation increased the flavor and general acceptability scores. It also improved the TPC and antioxidant capacity. The TPC of the developed beverage samples ranged from 65 to 97 mg/L. The fatty acid composition was rich in monounsaturated fatty acids as mainly oleic acid (>80%). The hazelnut milk beverage may have potential as a functional beverage in a daily diet to provide nutrients and energy.
- MakaleYalnız künye2022Eocene magmatism and associated Fe-Cu mineralization in northeastern Turkey: a case study of the Karadağ skarn
Sipahi, Ferkan; Saydam Eker, Çiğdem; Akpınar, İbrahim; Gücer, Mehmet Ali; Vural, Alaaddin; Kaygusuz, Abdullah; Aydurmuş, Tanju
The metallogenic belt containing numerous skarn mineralized systems starting from Eastern Europe continues through Turkey and Iran. The study area in the Eastern Pontides is within this metallogenic belt. The 44.39 ± 0.53 Ma Karadağ Intrusion sourced skarn mineralization is located along the granitoid-to-limestone contact. The Karadağ Intrusion is an arc-like pluton with medium–high K calc-alkaline and peraluminous–metaluminous affinity. The Karadağ Fe–Cu skarn mineralization (Gümüşhane, Turkey), an exoskarn, is hosted by Late Cretaceous limestone and consists of early garnet, clinopyroxene, and orthoclase with late epidote and chlorite. Primary ore minerals are magnetite and haematite, accompanied by minor amounts of chalcopyrite and pyrite. Pyroxene comprises mostly diopside and less hedenbergitic diopside and johannsenite. Wollastonite is very rare. Garnet is andradite and grossular–andradite. Thus, all these results imply that the Karadağ Fe–Cu skarn mineralization formed under relatively oxidized and Fe-rich conditions. The homogenization temperatures of the fluid inclusions vary from 189°C to 405°C for quartz and 186°C to 430°C for calcite. The salinity contents in the fluid inclusions are within 0.2–9 wt% NaCl equivalent for quartz and 0.4–14.8 wt% NaCl equivalent for calcite. First melting temperatures between −36.5 and −47.4°C were attained with the presence of NaCl–FeCl2± CaCl2 in the initial phase of fluid inclusions. The first melting in the later stage of fluid inclusions is between −3.8 and −17.2°C, thereby, supporting the existence of NaHCO3-Na2CO3-KCl-type salt composition. The δ18O values of minerals are 1.7–10.3‰ for garnet, 11.1–14.6‰ for quartz, 6.4 to 6.8‰ for epidote, and 2.8–3.8‰ for magnetite in the Karadağ skarn mineralization. The δ18O value of epidote indicates magmatic fluid, whereas those of garnet, magnetite, and quartz suggest magmatic fluids together with less meteoric effect. The δ18O values in limestone (18.7 to 22.3‰), marble (8.7‰), and calcite (10.5 to 12.2‰) were depleted relative to typical δ18O contents of marine carbonates (20 to 30‰). Moreover, the C isotope values of calcite (−5.4 to −1.4‰), marble (−2.1‰), and limestone (1.0 to 1.2‰) reflect those of metamorphic rocks and skarns (−4.0 to 3‰ and −18 to 2‰). Mineral paragenesis, fluid inclusion, and stable isotopic signatures are consistent with ore mineralization caused by the interaction of magmatic fluids with carbonate host rocks. Karadağ Fe-Cu skarn mineralization, associated with Karadağ postcollisional magmatism, is an example of skarn mineralized system in the Eastern Pontides.
- MakaleYalnız künye2022Evaluation of single particle drying characteristics using drying models and curve fitting
Celen, Pinar; Erdem, Hasan H; Pusat, Saban
In this study, Turkish lignite dried with hot air and superheated steam was experimentally investigated. Drying experiments were carried out at 120°C drying temperature and atmospheric pressure. Mass, center and surface temperature changes of lignite having a diameter of 30 mm were continuously measured. Hot air and superheated steam drying methods were compared, and it was found that, because of condensation in the initial stage of superheated steam, the moisture content of the lignite sample temporarily increased. On the contrary, the moisture content of the lignite sample dramatically reduced on drying with hot air. Six different thin-layer models describing the drying kinetics of lignite were fitted to the experimental data, with the Pusat model giving the best predictions with superheated steam drying and the Midilli model giving the best predictions with hot air drying of a single particle.
- MakaleAçık Erişim2022A new species of the harvestman genus Graecophalangium (Opiliones: Phalangiidae) from Turkey
Kurt, Kemal
A new harvestman species, Graecophalangium anatolicumsp. n. (Opiliones: Phalangiidae) is described based on males from Konya province, Turkey. Morphological characteristics features and photographs of the new species are presented. http://www.zoobank.org/urn:lsid:zoobank.org:pub:A74AF4CB-5E4A-4749-8B12-80E71E4E4D36.
- MakaleYalnız künye2022Chemical profile, antioxidant, antimicrobial, and enzyme inhibition activities of Pilosella hoppeana subsp. cilicica
Acet, Tuba
Pilosella hoppeana subsp. cilicica has been traditionally used for healing many diseases in folk medicine in Anatolia. However, there are, to date, no studies aimed to verify this local usage with scientific data. In the present study, phenolic content and biological activities such as the antioxidant, antimicrobial and enzyme inhibition activities of different extracts of this plant’s aerial part were investigated for the first time. According to the obtained data, the biological activity of methanol extract was found to be significantly higher than the others. Moreover, the major components detected were chlorogenic acid (61.79 mg g−1 extract), apigenin (2.727 mg g−1 extract), and luteolin (1.110 mg g−1 extract) in this extract. This extract showed a strong enzyme inhibitory activity including α-amylase (96.66 mmol ACAE g−1 extract), α-glucosidase (17.27 mmol ACAE g−1 extract), AChE (10.42 mg GALE g−1 extract), and BChE (102.35 mg GALE g−1 extract). On the other hand, the extract exhibited remarkable antimicrobial effect on Yersinia pseudotuberculosis, and Staphylococcus epidermidis (64 µg/mL MIC value); intermediate (128–256 µg/mL MIC value) antimicrobial activity on Proteus vulgaris, Listeria innocua, and vancomycin-resistant Enterococcus faecium. To sum up, it is clearly seen that Pilosella hoppeana subsp. cilicica has significant potential as a source of bioactive compounds in pharmaceutical industries.
- MakaleAçık Erişim2022Innovative approaches to the trend assessment of streamflows in the Eastern Black Sea basin, Turkey
Akçay, Fatma; Kankal, Murat; Şan, Murat
The issue of detection of hydrometeorological trends remains relevant because of the importance of climate change in design, operation, and management studies related to water resources. This study examines the effects of changes in climate and land use on monthly flows (1962–2018) in the Eastern Black Sea basin, Turkey, using innovative trend analysis methods. In this context, innovative polygon trend analysis (IPTA) and innovative trend significance test (ITST) were used to detect the trends and compared with Mann-Kendall test. Only stations with homogeneous data that did not experience non-climatic changes are used in the analysis. IPTA and ITST approaches are much more sensitive than Mann-Kendall in detecting trends. Although the innovative methods are mostly compatible with each other (90%), IPTA presents additional information about trend transitions between successive parts of time series. Results indicate significant decreasing trends in summer months, likely due to diminishing precipitation and effective evaporation.
- MakaleYalnız künye2022Roza: a new and comprehensive metric for evaluating classification systems
Melek, Mesut; Melek, Negin
Many metrics such as accuracy rate (ACC), area under curve (AUC), Jaccard index (JI), and Cohen’s kappa coefficient are available to measure the success of the system in pattern recognition and machine/deep learning systems. However, the superiority of one system to one other cannot be determined based on the mentioned metrics. This is because such a system can be successful using one metric, but not the other ones. Moreover, such metrics are insufficient when the number of samples in the classes is unequal (imbalanced data). In this case, naturally, by using these metrics, a sensible comparison cannot be made between two given systems. In the present study, the comprehensive, fair, and accurate Roza (Roza means rose in Persian. When different permutations of the metrics used are superimposed in a polygon format, it looks like a flower, so we named it Roza.) metric is introduced for evaluating classification systems. This metric, which facilitates the comparison of systems, expresses the summary of many metrics with a single value. To verify the stability and validity of the metric and to conduct a comprehensive, fair, and accurate comparison between the systems, the Roza metric of the systems tested under the same conditions are calculated and comparisons are made. For this, systems tested with three different strategies on three different datasets are considered. The results show that the performance of the system can be summarized by a single value and the Roza metric can be used in all systems that include classification processes, as a powerful metric.
- MakaleYalnız künye2021The effect of homocysteine on the expression of CD36, PPARγ, and C/EBPα in adipose tissue of normal and obese mice
Mentese, Ahmet; Dogramaci, Seniz; Demir, Selim; Yaman, Serap Ozer; Ince, Imran; Altay, Diler Us; Erdem, Mehmet; Turan, Ibrahim; Alver, Ahmet
The purpose of this study was to investigate the effect of homocysteine (Hcy) on CD36, PPARγ, and C/EBPα gene and protein expression in adipose tissue obtained from normal and high-calorie diet obesity models. CD36, PPARγ, and C/EBPα gene expression and protein levels in adipose tissue specimens were determined using the RT-PCR and ELISA methods, respectively. Significantly increased CD36 gene expression was observed in adipose tissue from obese mice, while Hcy significantly reduced CD36 gene expression in adipose tissue from normal and obese mice. PPARγ and C/EBPα gene expression levels decreased significantly in all groups compared to the normal group. In addition, levels of both PPARγ and C/EBPα gene expression were lower with Hcy supplementation compared to their own controls. In conclusion, Hcy’s reduction of CD36 gene expression in adipose tissue may be one probable factor in hyperhomocysteinemia representing an independent risk factor for cardiovascular diseases.
- MakaleYalnız künye2021Determining the phenolic components by using HPLC and biological activity of Centaurea triumfetti
Acet, Tuba
Centaurea species belonging to Asteraceae family are traditionally used herbs in treating many diseases in Anatolia. In the present study, I aimed to determine the biological activities and phenolic contents of the extracts of the aerial parts of Centaurea triumfetti collected from areas with extreme climatic conditions. The determination of antioxidant activity was performed using in vitro assays such as ABTS (2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (1,1-diphenyl-2-picrylhydrazyl). Disc diffusion and microdilution methods were used for determine of antimicrobial activity. Besides that, the diabetes-related inhibition activities of enzymes such as alpha-glucosidase and alpha-amylase were determined using colorimetric methods. The phenolic components of the extracts were analysed by using HPLC. The biological activity of ethyl acetate extracts of the stem was found to be higher those than that of other extracts. This extract was also found to have high antimicrobial and enzyme inhibition activity. Moreover, the major component of the extract was found to be chlorogenic acid. In conclusion, these results suggest that C. triumfetti has the potential for pharmaceutical usage.
- MakaleYalnız künye2021Biological activity of Psephellus appendicigerus as a natural agent
Acet, Tuba; Özcan, Kadriye; Sefalı, Abdurrahman
Psephellus appendicigerus, is a plant endemic to Turkey, belonging to the Asteraceae family, which is traditionally used in folk medicine in Turkey. The aim of this study is to reveal for the first time the biological activities of this plant and evaluate its potential use as a natural product. For this reason, different extracts (ethanol, methanol, ethyl acetate, and hexane) of the plant’s aerial parts were used in determining the antioxidant (2,20-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid and 1,1-diphenyl-2-picrylhydrazyl assays), antimicrobial (disc diffusion and microdilution methods), and enzyme inhibition activity (calorimetric methods) related to diabetes (α-amylase and α-glucosidase). Moreover, the phenolic constituents were analysed by high performance liquid chromatography. Methanol extract of the plant exhibited significant biological activity compared to other extracts. This extract had the highest amount of chlorogenic acid as phenolic compound. In addition, all extracts showed inhibition against at least one test microorganism. According to the results, P. appendicigerus has the potential to be used as a natural antioxidant, antimicrobial and enzyme inhibitor.
- MakaleYalnız künye2021A copula approach for sea level anomaly prediction: a case study for the Black Sea
Yavuzdoğan, Ahmet; Tanır Kayıkçı, Emine
Forecasting future sea levels is of great importance in terms of the conservation of coastal areas, monitoring and forecasting coastal ecosystems, and the maintenance and planning of coastal structures. In addition, highly accurate sea level forecasts allow adequate water management policies and coastal infrastructures to be developed. Today, many methods, such as harmonic analyses, artificial neural networks and support vector machines, are used to predict sea level anomalies. In this study, a novel approach based on Copula functions is presented for the prediction of sea level anomalies. The primary purpose of this study is to examine the applicability and capability of Copula-based prediction models in predicting short-term variations in the sea level. The minimum 95% correlations and minimum 22 mm RMSE values in sea level anomaly predictions during the testing period indicate that the Copula approach can be a powerful tool in the prediction of sea level anomalies.