Electrochemical catechol biosensor based on β-cyclodextrin capped gold nanoparticles and inhibition effect of ibuprofen

Herein, β-cyclodextrin-capped gold nanoparticle surface designed for tyrosinase (Tyr)-based nanosensor is proposed and demonstrated. Integration of the β-cyclodextrin-capped gold nanoparticles on graphite electrode surface was achieved via drop-casting method, Tyr was immobilized on the modified electrode and then used as drug inhibition platform with catechol as the substrate. All optimization studies that affect biosensor response were conducted, and catechol was detected in the linear range of 1.56 μM-25μM catechol concentration with a limit of detection of 0.42 μM and sensitivity of 2.094 μA.μM−1. cm-2. Tyr inhibition was followed with ibuprofen drug active compound with a 15 min incubation time, and the I50 value was found as 213 μM. The sensor is the first in the literature to use an electrochemical method for β-cyclodextrin-capped gold nanoparticles based Tyr biosensor and ibuprofen inhibition. This sensor presents an easy fabrication method, excellent sensor properties, and ibuprofen inhibition capabilities. As a result, it is proposed that the designed sensor is an ideal marker for detecting Tyr inhibition using electrochemical methods and an ibuprofen-based cosmetic cream formulation could be a viable option in the cosmetic market

Benthic Faunal Assemblages of the Holocene Sediments from the Southwest Black Sea Shelf

Benthic faunal content (benthic foraminifera, mollusca and ostracoda) of sediment cores from the SW Black Sea shelf were examined. Based on the vertical distribution of abundance and diversity of the benthic fauna, three benthic assemblages were distinguished. These assemblages are BF1, BF2 and BF3, and reflect the changes in bottom water from the termination of the Neoeuxinian period to present. BF1 displays high abundance and diversity in the surroundings of the Bosporus channel, diminishing in the shelf sediments further away from the channel. In the Mid-Shelf and Outer Shelf, it displays low abundance and low diversity. BF1 which started to be deposited at about 6 ky BP reflects the source effect of the saline Mediterranean lower layer, diminishing in strength toward more distal areas. In the Outer Shelf, changing foraminiferal faunal content may suggest that relatively low salinity conditions in the bottom water were established after similar to 4 ky BP. BF2 consists of a mixed fauna (brackish and euryhaline Mediterranean species), suggesting transitional conditions with intrusion of Mediterranean water earlier than similar to 8 ky BP. BF3 corresponds to the Neoeuxinian lake phase of the Black Sea

Oligocene vegetation and climate characteristics in north-west Turkey: data from the south-western part of the Thrace Basin

In this paper we present the first palynomorph and mollusc assemblages from the sediments in three different sections. From east to west, these are the Sevketiye (northern Biga Peninsula), the Tayfur (Gelibolu Peninsula) and the Kuzu harbour (Gokceada) (parts of the Danismen Formation) sections in the south and south-western side of the Thrace Basin (north-west Turkey), with the aim of obtaining information about the composition and structure of vegetation and climate during the Oligocene. The stratigraphic interval extends from late Rupelian to Chattian. The Danismen Formation in the Sevketiye section yielded a palynomorph association with abundant coastal palms (Arecaceae; Lepidocaryoidae), and mangrove pollen (Pelliciera). A similar assemblage from the Kuzu harbour section was also obtained, with minor contributions of mangrove elements Nypa and Acrostichum aureum, Arecaceae type palm, undifferentiated dinoflagellate cysts and microforaminiferal linings. These palynomorph assemblages, combined with the mollusc data, indicate that low-lying coastal environments prevailed. In contrast, the palynomorphs from the Tayfur section represent a non-marine environment lacking mangrove elements, palm trees, dinoflagellate cysts and microforaminiferal linings. The diversity of angiosperm taxa in the Tayfur palynoflora, which form the bulk of the assemblage, indicates terrestrial vegetation. Quantitative palaeoclimate analyses are based on the Coexistence Approach method, and yield over 22 degrees C at the coast as indicated by mangrove elements and palms in the Sevketiye and Kuzu harbour palynofloras. For the Tayfur palynoflora, mean annual temperature ranged between 16.5 and 21.3 degrees C. This indicates a climate cooling, corresponding to the transition from Rupelian to Chattian, and resulted in the pollen changes from mangrove bearing coastal deposits to more inland vegetation

Evolution of Can-Etili (Canakkale-NW Turkey) lignite basin: Sedimentology, petrology, palynology and lignite characterization

This study examines the development and sedimentology of Can-Etili lignite basin in Biga Peninsula (NW Turkey) along with the palynologic and petrographic properties of the coals in this region. The Can-Etili lignite basin discordantly overlies Oligocene-aged Can volcanics. The basin consists of caldera type sedimentation developed by the combined effects of volcanism and tectonics. The volcanic rocks forming the basement of the basin consist of andesitic, dacitic and basaltic lava flows as well as agglomerates, tuff and silicified tuffs, and kaolin which is their alteration product. The basement volcanic rocks cooled from high potassium and calc-alkaline magma. The trace element geochemistry of different rocks within the volcanics reveals that they are from a volcanic arc. The Can Formation contains lignites and consists of 6 lithofacies representing alluvial, fluvial, marsh and lacustrine environments. These lithofacies are the lower volcanogenic conglomerate, the claystone, the lignite, the laminated organic claystone, the tuff intercalated sandstone-siltstone and the upper volcanogenic conglomerate. The lignite in the basin is limnic and is formed in a non-fluvial marsh and marsh-lake environment. An abundant percentage of vegetation (Engelhardia, Sapotaceae, Cyrillaceae) is compatible with temperate and subtropical climatic conditions in the basin during sedimentation of lignite. The coals of Can-Etili basin are humic with high sulfur content (6-6.5% average) mostly containing huminite compounds belonging to the class of lignite-low bituminous (C-A) coal. Their coalification rank is between 0.38% and 0.56% Ro. The coals are formed in limnic-limnotelmatic marsh zones based on their microlithotype components. The inorganic components of the coal mostly consist of pyrite and clay. The trace elements, As, Th, U and V, are higher than international coal standards. The coal quality is adversely affected by high sulfur content and sulfur driven trace element enrichments. The lignite reserve (possible-proved) of Can-Etili basin is greater than a hundred million tons, and the average coal seam thickness is 17 m. The lignite production in the basin is 3 mt/year and 1.8 million tons of this are used in the local thermal power plant. (C) 2015 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion Research. Published by Elsevier B.V. All rights reserved

Paramagnetic characterization of fossil mollusc shells at eastern part of the old Konya lake: its importance for EPR dating

Fossil mollusc shells are used for dating geological materials because they are well preserved throughout geological time. In this study, the radicals in the structure of fossil mollusc shells (Dreissena iconica, Valvata piscinalis, Bithynia tentaculate, Unio pictorum) collected from the Eastern Part of Old Konya Lake in Türkiye were investigated by EPR technique. For all fossil shells, microwave and temperature dependence of the signals were examined, and the signals suitable for dating are discussed. Characteristic features of intrinsic and impurity-related radicals were identified and the importance of paleontological evaluation of molluscs to get a reliable equivalent dose in EPR dating studies was emphasised