Zinc and copper content in marine fish samples collected from the eastern Mediterranean Sea

Zinc and copper contents in the edible parts (muscle, fillet) of 49 commercially used fish species from the eastern Mediterranean Sea (Izmir Outer Bay, Homa Lagoon/Izmir and Mersin Bay) were determined by differential pulse stripping anodic voltammetry. In the sample preparation step, all frozen fish samples were lyophilized, milled in a ball mill and finally decomposed in an oxygen plasma ashing chamber. Among the three sampling locations, the highest zinc concentration was found in Mediterranean shad (Alosa fallax nilotica) from Izmir Outer Bay with 9.73 mg/kg wet weight and the highest copper content was found in derbio (Trachinotus ovatus) from Homa Lagoon with 1.14 mg/kg wet weight. The accuracy of the concentrations determined in this study was checked by the measurements of certified reference material no. 422 cod muscle from the Commission of the European Communities, Community Bureau of Reference. All zinc and copper concentrations observed in species of the eastern Mediterranean Sea showed that fish from this area are good sources of these essential elements.     

Crosslinked DADMAC polymers as cationic super absorbents

Loosely crosslinked cationic polyelectrolytes (polyquats) with super-water-sorption abilities are presented, for the first time. Hydrogels obtained by radically initiated copolymerization of N,N-diallyl, N,N-dimethyl ammonium chloride (DADMAC) with N-vinyl 2-pyrrolidone (NVP) in presence of N,N,N′,N′-tetraallyl piperazinium dichloride (TAP) as crosslinker showed reasonably high equilibrium swelling ratios, as high as those for poly(acrylic acid)-based super absorbents.The highest swelling ratios (up to 360) were attained by fully cationic hydrogels derived from DADMAC and 0.5% TAP. The hydrogels with 0.5–5% crosslinkers exhibited rapid expansion in neutral water, so that the equilibrium swelling values were attained within 2–3 min. The crosslinking densities of the gels were estimated by Flory-type swelling model using “phantom network elasticity” for the elastic contribution. This estimation revealed low crosslinking efficiencies of TAP (0.24–0.35) due to its double cationic charge.In the study “the salt effect” and effects of the comonomer ratios and crosslinker contents on the swellings were also investigated.     

Modification of Food-Contacting Surfaces by Plasma Polymerization Technique: Reducing the Biofouling of Microorganisms on Stainless Steel Surface

In this study, the prevention of the attachment of test microorganism Enterobacter sakazakii onto stainless steel (SS 316) surfaces by radio frequency (RF) plasma polymerization (PlzP) technique using several hydrophilic monomers as precursors was reported. Different plasma conditions (RF discharge power of 20–80 W with exposure time of 10 min) were employed during the modifications. PlzP-modified surfaces were characterized in detail by static contact angle measurements in order to state the change of surface hydrophilicity. The surface topology of unmodified and PlzP [ethylenediamine (EDA)]-modified SS 316 plates was characterized by atomic force microscopy. The attachment of the model microorganism on the SS 316 surface modified by plasma using EDA at 45 W and 10 min was reduced by 99.74% in comparison to the unmodified control surface. For equilibrium adsorption behavior, Freundlich and Langmuir models were attempted and model parameters for Freundlich (K _F and 1/n) and for Langmuir (a and b) were obtained. The values of the K _F and 1/n were 5.6 and 0.58 and 0.9 and 0.39, respectively; the values of a and b were 25 × 10⁴ and 1.82 × 10⁻⁸ and 0.3 × 10⁴ and 7.96 × 10^-8, for bare and PlzP-EDA-modified SS 316 surfaces, respectively. As a result, PlzP technique was found to be an alternative simple method to decrease the microbial attachment and create bacterial anti-fouling surfaces.     

Synthesis and Characterization of Lipophilic Polymeric Adsorbent Resins for Recovery of Anthocyanins from Black Carrot

The aim of this study was to synthesize and characterize the various polymeric adsorbents which are used in the recovery of black carrot anthocyanins by the solid-phase extraction technique. In this context, acrylic and methacrylic monomers were polymerized with the free radical polymerization technique. In resin synthesis, four different crosslinker monomers, different monomer/crosslinker and monomer/diluent ratios were studied. The characterizations of the polymeric adsorbents were designed by size distribution, polymerization yield, scanning electron microscope images and swellability ratio in water and ethanol. In order to determine the best production conditions for polymer adsorbents, they were tested in a model batch system. The T-10-coded adsorbent demonstrated the best performance. The anthocyanins of the black carrot were recovered successfully from carrot juice by using the packed bed adsorption column system which is prepared with T-10. At the end of the study, 3.01 g color components were obtained from 1 L of black carrot juice.     

Dominant sets based movie scene detection

Multimedia indexing and retrieval has become a challenging topic in organizing huge amount of multimedia data. This problem is not a trivial task for large visual databases; hence, segmentation into low- and high-level temporal video segments might improve the realization of this task. In this paper, we introduce a weighted undirected graph-based movie scene detection approach to detect semantically meaningful temporal video segments. The method is based on the idea of finding the dominant scene of the video according to the selected low-level feature. The proposed method starts from obtaining the most reliable solution first and exploit each solution in the subsequent steps recursively. The dominant movie scene boundary, which can be the highest probability to be the correct one, is determined and this scene boundary information is also exploited in the subsequent steps. We handle two partitioning strategies to determine the boundaries of the remaining scenes. One is a tree-based strategy and the other is an order-based strategy. The proposed dominant sets based movie scene detection method is compared with the graph-based video scene detection methods presented in literature.     

Optimization of temperature and light intensity for improved photofermentative hydrogen production using Rhodobacter capsulatus DSM 1710

Photofermentative hydrogen production is influenced by several parameters, including feed composition, pH levels, temperature and light intensity. In this study, experimental results obtained from batch cultures of Rhodobacter capsulatus DSM 1710 were analyzed to locate the maximum levels for the rate and yield of hydrogen production with respect to temperature and light intensity. For this purpose, a 3^k general full factorial design was employed, using temperatures of 20, 30 and 38 °C and light intensities of 100, 200 and 340 W/m². ANOVA results confirmed that these two parameters significantly affect hydrogen production. Surface and contour plots of the regression models revealed a maximum hydrogen production rate of 0.566 mmol H₂/L/h at 27.5 °C and 287 W/m² and a maximum hydrogen yield of 0.326 mol H₂/mol substrate at 26.8 °C and 285 W/m². Validation experiments at the calculated optima supported these findings.     

Chemical and antioxidant properties of pomegranate cultivars grown in the Mediterranean region of Turkey

Arils from six pomegranate (Punica granatum L.) cultivars obtained from various sites from the Mediterranean region of Turkey were evaluated for their chemical and antioxidant properties. These properties included total phenolics (TP), total monomeric anthocyanins (TMA), soluble solids (TSS), titratable acidity (TA), individual sugars and organic acids. Antioxidant capacities of arils were determined by both the ferric reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. The antioxidant capacities averaged 5.60 and 7.35 mmol TE/l by the TEAC and FRAP methods. Variability among cultivars was greatest for TMA content (CV 132%); individuals ranged from 6.1 to 219 mg cy3-Gluc l⁻¹. TP means averaged 1507 mg GAE/l. Levels of FRAP, TEAC, TP, and TMA were strongly correlated (r = 0.82–0.96). The major sugars were fructose (6.4 g/100 ml) and glucose (6.8 g/100 ml), the major acids were citric (1.78 g/100 ml) and malic (0.12 g/100 ml).     

Forecast Combination by Using Artificial Neural Networks

One of the efficient ways for obtaining accurate forecasts is usage of forecast combination method. This approach consists of combining different forecast values obtained from different forecasting models. Also artificial neural networks and fuzzy time series approaches have proved their success in the field of forecasting. In this study, a new forecast combination approach based on artificial neural networks is proposed. The forecasts obtain from different fuzzy time series models are combined by utilizing artificial neural networks. The proposed method is applied to index of Istanbul stock exchange (IMKB) time series and the results are compared to other forecast combination methods available in the literature. As a result of the implementation, it is seen that the proposed forecast combination approach produces better forecasts than those produced by other methods.     

Determination of Optimum Velocity for Various Nanofluids Flowing in a Double-Pipe Heat Exchanger

Piping is one of the most important issues in the cost of process factories. It is known that 80% of bought equipment cost or 20% of overhead capital can belong to piping cost in a fluid-process factory. Pipe diameter and therefore flow velocity strongly affect the existing value of the factory regarding the consumed electric energy and fitting cost of pipes, pumps, and valves. We give a detailed cost analysis model for the pure fluids of water, motor oil, glycerin, ammonia, methanol, ethanol, ethylene glycol, and propane and their nanofluid mixtures with Ti and TiO₂ particles in liquid phase flowing in the tube side of a double-pipe heat exchanger. Pressure drop and pumping power values increase with flow velocity but total cost values show an arc with it. The clear outcome is that there is a minimum cost value as a result of the analyses for each investigated fluids. Moreover, validation of the model is performed by plotting the calculated items in figures such as total heat transfer coefficient versus Reynolds number, pressure drop versus Reynolds number, and friction factor versus mass flow rate. Characteristics of the trend lines in these figures are seen as they should be.