Host-sensitized phosphorescence of Mn4+, Pr3+,4+ and Nd3+ in MgAl2Si2O8

Mn⁴⁺ doped and Pr^3+,4+, Nd³⁺ co-doped MgAl₂Si₂O₈-based phosphors were first of all synthesized about 1300 °C. They were characterized by thermogravimetry (TG), differential thermal analysis (DTA), X-ray powder diffraction (XRD), photoluminescence (PL) and scanning electron microscopy (SEM). The luminescence mechanism of the phosphors, which showed broad red emission bands in the range of 610–715 nm and had a different maximum intensity when activated by UV illumination, was discussed. Such a red emission can be attributed to the intrinsic d–d transitions of Mn⁴⁺.     

Antioxidant activity and phenolic content of wine vinegars produced by two different techniques

BACKGROUND: The presence of phenolics in fruit, red wine and vinegar has positive health effects due to their significant antioxidant activity. The aim of the study was to determine the effects of two different vinegar production methods on antioxidant activity and phenolic level of vinegars derived from Ulugbey Karasi grapes. Traditional surface and industrial submerge methods were used to make vinegar. Samples were taken from fresh red grape juice, maceration, wine, traditional vinegar and industrial vinegar. RESULTS: Total phenolic content of traditional and industrial vinegar samples were 2690 mg L^?1 and 2461 mg L^?1 GAE, respectively. ORAC values of traditional and industrial vinegar samples were 10.50 µmol mL^?1and 8.84 µmol mL^?1 TE, respectively. Antioxidant activity values of traditional and industrial vinegars were 13.50 mmol L^?1 and 10.37 mmol L^?1 TEAC, respectively. Gallic acid, catechin, epicatechin, chlorogenic acid, caffeic acid, syringic acid, p‐coumaric acid and ferulic acid were detected in grape juice, wine and vinegar samples. The content of catechin in industrial vinegar (27.50 mg L^?1) was significantly higher than that of in traditional vinegar (13.76 mg L^?1) (P < 0.05). Traditional vinegar had higher amounts of chlorogenic and syringic acids than the industrial vinegar (P > 0.05). CONCLUSION: Results of this study showed that different production methods affected the functional constituents of wine vinegars. Copyright © 2010 Society of Chemical Industry     

The effect of exfoliation and plasma application on the properties of continuous graphene oxide fiber

This study has been performed on continuous graphene oxide fiber produced by different production parameters which has very large potential application areas such as electronic/smart textiles, sensors, energy. In this study, three different graphene oxide dispersion preparation methods; namely, Modified Hummers, Modified Hummers on exfoliated graphite and Modified Hummers with plasma application; have been used to prepare coagulated continuous graphene oxide fibers. The effect of production parameters on properties of continuous graphene oxide fibers have been measured by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-Ray Photoelectron Microscopy (XPS), tensile tester, electrical conductivity device. It was observed that exfoliation process results with decrease of fiber Tex count, fiber surface roughness, oxygen functional groups and an increase of breaking strength and electrical conductivity, while plasma application results to an increase of surface roughness of fiber, oxygen functional groups and decrease of breaking strength of fiber.     

Binding of methyl orange or ethyl orange dyes by some dioxolane copolymers: Synthesis of the copolymers and thermodynamics of the dye–copolymer interactions

The extent of binding of methyl orange or ethyl orange by (2‐phenyl‐1,3‐dioxolane‐4‐yl) methyl methacrylate (PDMMA), 2‐hydroxyethyl methacrylate (HEMA), and vinyl‐pyrrolidone (VPy) copolymers has been investigated by the equilibrium dialysis method. The dialysis experiments have been carried out in a Tris (hydroxy methyl) aminomethane buffer (pH = 7) and at the temperatures of 15, 25, and 35°C. The PDMMA‐co‐HEMA and PDMMA‐co‐VPy copolymers have been prepared in the laboratory by using the related monomers in different ratios. The synthesized products were analyzed by Fourier Transform‐infrared spectroscopy (FTIR), proton nuclear magnetic resonance (¹H NMR) spectroscopy, differential thermal analysis (DTA), and differential scanning calorimetry (DSC) techniques. The binding extent of the dyes by the copolymers was determined by ultraviolet (UV) absorbance measurements. The results indicate that the extent of binding is relatively higher for ethyl orange than that for methyl orange under identical conditions. The binding slightly decrease with increasing temperature, and it is accompanied with favorable free energy, and exothermic enthalpy change within the temperature range studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3355–3361, 2004     

Temperature rises during tooth bleaching with different light-curing units

The aim of this study was to evaluate the influence of three different light-curing units on the temperature rise induced in the pulpal cavity, when bleached with 35% hydrogen peroxide (HP). Forty extracted maxillary central incisors were randomly divided into four groups according to photoactivation procedure (n = 10). Whiteness HP (WHP) bleaching agent which contains 35% HP bleach was placed on the facial tooth surface and no photoactivation device was used (control); an blue light-emitting diode (LED, 40 s), a diode laser (4 W, Continous mode, 20 s), and Nd:YAG laser (4 W, 60 Hz frequency, 20 s). Temperature rise in the pulpal chamber was measured with a J-type thermocouple wire that was connected to a data logger before and immediately after each 20–40 s application. One tooth of each group was selected for scanning electron microscope analysis. Data were analyzed using one-way ANOVA followed by the Games Howell post hoc test at a preset α of 0.05. One-way ANOVA revealed that there was a significant difference among the light-curing units (p < 0.05) and between control group and light-curing units (p < 0.05). The Nd:YAG induced significantly, which resulted in higher temperature increase than other light-curing units (10.7 °C). The LED unit produced the lowest temperature changes (3.2 °C) among the light-curing units. The presence of the bleaching gel did not cause a temperature increase in control group (0 °C). The results suggested that using light-curing units caused temperature changes in the intrapulpal cavity during tooth bleaching. The use of LED will be more safer for pulpal health when assisted with WHP bleaching gel.     

Band alignment of Cd(1 − x)ZnxS produced by spray pyrolysis method

Cd_(1 − x)Zn_xS thin films have been grown on glass substrates by the spray pyrolysis method using CdCl₂ (0.05 M), ZnCl₂ (0.05 M) and H₂NCSNH₂ (0.05 M) solutions and a substrate temperature of 260 °C. The energy band gap, which depends on the mole fraction × in the spray solution used for preparing the Cd_(1 − x)Zn_xS thin films, was determined. The energy band gaps of CdS and ZnS were determined from absorbance measurements in the visible range as 2.445 eV and 3.75 eV, respectively, using Tauc theory. On the other hand, the values calculated using Elliott-Toyozawa theory were 2.486 eV and 3.87 eV, respectively. The exciton binding energies of Cd_0.8Zn_0.2S and ZnS determined using Elliott-Toyozawa theory were 38 meV and 40 meV, respectively. X-ray diffraction results showed that the Cd_(1 − x)Zn_xS thin films formed were polycrystalline with hexagonal grain structure. Atomic force microscopy studies showed that the surface roughness of the Cd_(1 − x)Zn_xS thin films was about 50 nm. Grain sizes of the Cd_(1 − x)Zn_xS thin films varied between 100 and 760 nm.     

The Assessment of Irrigation Efficiency in Buyuk Menderes Basin

While extending irrigated areas to augment agricultural production, irrigation efficiency should be increased not only to improve the agricultural production but also to obtain the sustainable use of valuable and limited water resources. Through the use of Data Envelopment Analysis (DEA), which is a linear programming technique to determine the relative efficiency of a decision-making unit, it is possible to decide whether the use of water in an irrigation district is efficient or not. In this study, an input oriented DEA model is constituted to focus on the efficient use of inputs, and the method is applied to the irrigation districts having similar types of agriculture in the Buyuk Menderes Basin, Turkey. This paper aims to determine the efficient irrigation district(s), in other words where the application of water is the most profitable, considering two inputs; water volume supplied and the total irrigated area, and one output, the total value of agricultural production. The weight restrictions consistent with decision makers’ value judgements are added as constraints into the DEA models to prevent excessive weight flexibility assigned to inputs and outputs. The results have provided the efficiency scores of the irrigation districts and numerically delineated desired features of the irrigation districts for maximum efficiency. The analyses for three study years have inferred the robustness of the results. It is concluded that DEA is a practical tool for detecting local inefficiencies and proposing possible improvements for irrigation districts that could offer the greatest potential for growth.     

Oxidative Stability and In Vitro Release Properties of Encapsulated Wheat Germ Oil in Saccharomyces cerevisiae Cell-Based Microcapsules

This research aims to evaluate the feasibility of Saccharomyces cerevisiae cell-based microencapsulation for wheat germ oil (WGO) based on oxidative stability and in vitro release properties. Microencapsulation of samples is achieved by freeze-drying WGO-in water emulsions containing alive, non-plasmolyzed, and plasmolyzed yeast cells. The encapsulation efficiency (EE), loading capacity (LC), release characteristics, and oxidative stability of WGO are determined before and after microencapsulation. The amount of β-carotene in the digesta is used to evaluate the release properties. Plasmolyzed yeast cells yield the highest EE (43.1%) and LC (216.5 g kg⁻¹). In cases where alive and non-plasmolyzed yeast cells were used as an encapsulant, a higher release rate was obtained in esophagus-stomach conditions, while higher digestion took place mainly in the duodenum and ileum with plasmolyzed cells. Encapsulation of WGO in plasmolyzed yeast cells provide the lowest peroxide and p-anisidine values and the highest oxidative protection during the accelerated oxidation test at 60 °C for 24 days. This result is also confirmed by Rancimat induction time. Practical Applications: Removing the plasma content by plasmolysis changes the structure of the yeast cell membrane and improves the encapsulation ability and release properties. Encapsulation of WGO with plasmolyzed yeast cells provides superiority in oxidative stability compared to native WGO. The potential value of WGO as an ingredient in the preparation of functional foods could be achieved by yeast cell encapsulation.     

Sustainability Issues in Water Management

In the 1992 Rio World Summit on Environment and Development/UNCED), water resources are indicated to remain at the core of sustainable development and, thus, they are to be managed and developed on a sustainable basis. Sustainability is a philosophical concept and thus difficult to measure. Yet, we need to describe it on rather precise terms to assess whether our water management practices are sustainable and to ensure sustainability in decision making for management. To this end, a number of sustainability criteria have been defined, based on quantifiable measures, without overlooking immeasurable aspects of sustainable development. This paper considers economic, social and environmental dimensions of sustainability as the basic criteria to be pursued in evaluating how effective our water management plans are in achieving sustainability. On the other hand, actual case studies are needed to test the usefulness of selected criteria by using computer-based interactive optimization and simulation models with associated databases embedded into a decision support system (DSS). The study herein intends to present such a case study based on economic, social and environmental criteria to assess sustainability in management of the Gediz River Basin in Turkey. Various management scenarios developed for the basin are evaluated within a DSS while ensuring multi-stakeholder involvement in defining the three sustainability criteria. The case study is a result of the analyses carried out in SMART (Sustainable Management of Scarce Resources in the Coastal Zone) and OPTIMA (Optimization for Sustainable Water Resources Management) projects funded respectively by the 5^th and 6^th Framework Programmes of the European Union.