Fixed point theorems in new generalized metric spaces

The aim of our paper is to present new fixed point theorems under very general contractive conditions in generalized metric spaces which were recently introduced by Jleli and Samet in [Fixed Point Theory Appl. 2015 (2015), doi: 10.1186/s13663-015-0312-7]. Although these spaces are not endowed with a triangle inequality, these spaces extend some well known abstract metric spaces (for example, b-metric spaces, Hitzler–Seda metric spaces, modular spaces with the Fatou property, etc.). We handle several types of contractive conditions. The main theorems we present involve a reflexive and transitive binary relation that is not necessarily a partial order. We give a counterexample to a recent fixed point result of Jleli and Samet. Our results extend and unify recent results in the context of partially ordered abstract metric spaces.     

Two‐way and three‐way approaches to ultra high performance liquid chromatography–photodiode array dataset for the quantitative resolution of a two‐component mixture containing ciprofloxacin and ornidazole

Two‐way and three‐way calibration models were applied to ultra high performance liquid chromatography with photodiode array data with coeluted peaks in the same wavelength and time regions for the simultaneous quantitation of ciprofloxacin and ornidazole in tablets. The chromatographic data cube (tensor) was obtained by recording chromatographic spectra of the standard and sample solutions containing ciprofloxacin and ornidazole with sulfadiazine as an internal standard as a function of time and wavelength. Parallel factor analysis and trilinear partial least squares were used as three‐way calibrations for the decomposition of the tensor, whereas three‐way unfolded partial least squares was applied as a two‐way calibration to the unfolded dataset obtained from the data array of ultra high performance liquid chromatography with photodiode array detection. The validity and ability of two‐way and three‐way analysis methods were tested by analyzing validation samples: synthetic mixture, interday and intraday samples, and standard addition samples. Results obtained from two‐way and three‐way calibrations were compared to those provided by traditional ultra high performance liquid chromatography. The proposed methods, parallel factor analysis, trilinear partial least squares, unfolded partial least squares, and traditional ultra high performance liquid chromatography were successfully applied to the quantitative estimation of the solid dosage form containing ciprofloxacin and ornidazole.     

A note on “Some results on multi-valued weakly Jungck mappings in b-metric space”

The proofs of Theorems 2.1, 2.2 and 2.3 from [Olatinwo M.O., Some results on multi-valued weakly jungck mappings in b-metric space, Cent. Eur. J. Math., 2008, 6(4), 610–621] base on faulty evaluations. We give here correct but weaker versions of these theorems.     

Comparative Evaluation of the Effects of Bone Powder and Calcium Phosphate on Plant Growth and Development

The present study aimed to elucidate the effectiveness of inorganic element composition (except for calcium and phosphorus) of bone powder (BP) on some morphological (root and shoot length and dry weight) and biochemical (protein, sugar, chlorophyll, and inorganic element contents) parameters in bean seedlings. For this, BP was compared with calcium phosphate (CP), which is used as calcium and phosphorus source. Bone powder solutions (BPS) (0.5, 1, 1.5, and 2%) and CP solution (0.1 M) were applied to growing media of 12-day bean seedlings. Seedlings were harvested on 20th day. Both BPS and CP treatments significantly stimulated plant growth and increased dry weight, pigment, protein, and sugar contents compared to control seedlings; however, BPS treatments were found to be more effective than CP treatment. The best stimulatory effect on plant growth was determined at 1.5% concentration of BPS. Besides, BP treatment significantly increased contents of K, S, Fe, Zn, Mg, Mn, and Cu compared to control and CP-treated seedlings. This result clearly elucidated that the other elements existing in structure of BP also participated in plant structure, and they played important roles on growth and development in bean seedlings. It is possible to say that BP

may be used as an important source of the other inorganic elements as well as Ca and P in agriculture studies for improving of plant growth and productivity. This is the first report revealing the effect of BP on inorganic element content of plants.     

High temperature Ho<Subscript>2</Subscript>O<Subscript>3</Subscript>–ZrO<Subscript>2</Subscript> insulation coatings on AgMg sheathed Bi-2212 superconducting tapes by sol–gel technique for magnet technology

High temperature 0, 5, 8 and 12 mol % Ho₂O₃–ZrO₂ insulation coatings were successfully deposited on Ag and AgMg/Bi-2212 superconducting tapes using sol–gel technique for magnet technologies. With this purpose, transparent solutions were prepared from Ho and Zr-based precursor materials and then Ho₂O₃ effect on thermal, structural and microstructural properties were observed and discussed in the present study. It was found that Ho₂O₃ additive has a propensity to generate tetragonal ZrO₂ and help to stabilize it. It was observed that insulation coatings with a mosaic structure having cracks were fully compatible with Ag/AgMg sheathed Bi-2212 tape substrates because of oxygen permeability, high and low actual temperatures and W&R process in comparison with the conventional insulation process. In addition, surface roughness decreased with increasing Ho₂O₃ content, thereby decreasing the grain size. Although porosity values vary considerably from one porosity mesurement expression to another, porosities of the insulation coatings can be estimated to be in the range of 3 and 30 vol %.     

On fuzzy covering properties

The purpose of this paper is to introduce properties of the notion of α-compactness for fuzzy topological spaces. Moreover, α _c-compact spaces are introduced and properties of them are also discussed for fuzzy topological spaces.      

Determination and interference studies of bismuth by tungsten trap hydride generation atomic absorption spectrometry

The determination of bismuth requires sufficiently sensitive procedures for detection at the μg L⁻¹ level or lower. W-coil was used for on-line trapping of volatile bismuth species using HGAAS (hydride generation atomic absorption spectrometry); atom trapping using a W-coil consists of three steps. Initially BiH₃ gas is formed by hydride generation procedure. The analyte species in vapor form are transported through the W-coil trap held at 289 °C where trapping takes place. Following the preconcentration step, the W-coil is heated to 1348 °C; analyte species are released and transported to flame-heated quartz atom cell where the atomic signal is formed. In our study, interferences have been investigated in detail during Bi determination by hydride generation, both with and without trap in the same HGAAS system. Interferent/analyte (mass/mass) ratio was kept at 1, 10 and 100. Experiments were designed for carrier solutions having 1.0 M HNO₃. Interferents such as Fe, Mn, Zn, Ni, Cu, As, Se, Cd, Pb, Au, Na, Mg, Ca, chloride, sulfate and phosphate were examined. The calibration plot for an 8.0 mL sampling volume was linear between 0.10 μg L⁻¹ and 10.0 μg L⁻¹ of Bi. The detection limit (3 s/m) was 25 ng L⁻¹. The enhancement factor for the characteristic concentration (C_o) was found to be 21 when compared with the regular system without trap, by using peak height values. The validation of the procedure was performed by the analysis of the certified water reference material and the result was found to be in good agreement with the certified values at the 95% confidence level.     

Au/TiO2 nanorod‐based Schottky‐type UV photodetectors

TiO₂ nanorods (NRs) were synthesized on fluorine‐doped tin oxide (FTO) pre‐coated glass substrates using hydrothermal growth technique. Scanning electron microscopy studies have revealed the formation of vertically‐aligned TiO₂ NRs with length of ～2 µm and diameter of 110–128 nm, homogenously distributed over the substrate surface. 130 nm thick Au contacts using thermal evaporation were deposited on the n‐type TiO₂ NRs at room temperature for the fabrication of NR‐based Schottky‐type UV photodetectors. The fabricated Schottky devices functioned as highly sensitive UV photodetectors with a peak responsivity of 134.8 A/W (λ = 350 nm) measured under 3 V reverse bias. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Separation and preconcentration of trace manganese from various samples with Amberlyst 36 column and determination by flame atomic absorption spectrometry

This work assesses the potential of a new adsorptive material, Amberlyst 36, for the separation and preconcentration of trace manganese(II) from various media. It is based on the sorption of manganese(II) ions onto a column filled with Amberlyst 36 cation exchange resin, followed by the elution with 5 mL of 3 mol/L nitric acid and determination by flame atomic absorption spectrometry (FAAS) without interference of the matrix. Different factors including pH of sample solution, sample volume, amount of resin, flow rate of sample solution, volume and concentration of eluent, and matrix effects for preconcentration were investigated. Good relative standard deviation (3%) and high recovery (>95%) at 100 μg/L and high enrichment factor (200) and low analytical detection limit (0.245 μg/L) were obtained. The adsorption equilibrium was described well by the Langmuir isotherm model with maximum adsorption capacity of 88 mg/g of manganese on the resin. The method was applied for the manganese determination by FAAS in tap water, commercial natural drinking water, commercial treated drinking water and commercial tea bag sample. The accuracy of the method is confirmed by analyzing the certified reference material (tea leaves GBW 07605). The results demonstrated good agreement with the certified values.