Common Fixed Point Theorems for Finite Number of Mappings without Continuity and Compatibility on Fuzzy Metric Spaces

The aim of this paper is to prove some common fixed point theorems for finite number of discontinuous, noncompatible mappings on noncomplete fuzzy metric spaces. We improve extend and generalize several fixed point theorems on metric spaces,uniform spaces and fuzzy metric spaces.We also give formulas for total number of commutativity conditions for finite number of mappings.     

Fixed point and (DS)-weak commutativity condition in intuitionistic fuzzy metric spaces

The aim of this paper is to show that a common fixed point theorem can be proved for nonlinear contractive condition in intuitionistic fuzzy metric spaces without assuming continuity of any mappings. To prove the result we use new commutativity condition for mappings weaker than compatibility of mappings.     

Quenching of photoconductivity in Fe doped CdS thin films prepared by spray pyrolysis technique

Fe doped CdS films are prepared using spray pyrolysis technique. All the samples are found to be of single phase and crystallized in hexagonal lattice. The X-ray diffraction peaks position of Cd_1−xFe_xS shifts to higher angle with increasing Fe concentration indicating decrease in cell volume. The temperature dependence of resistivity follows Arrhenius behavior having lower activation energy with increasing Fe concentration in dark while there is a little variation in light. Pure CdS films are having large photoconductivity. Upon Fe incorporation, this photoconductivity gradually decreases and for concentration more than 20%, it is almost vanished. Note worthy observation is the changes seen in morphology with AFM, viz. nanorod features seen in CdS is changed to continuous nanorod like structures depicting signatures of Ostwald ripening.     

Anion recognition through amide-based dendritic molecule: a poly(vinyl chloride) based sensor for nitrate ion

Poly(vinyl chloride) (PVC)-based membranes of N,N-bis-succinamide-based dendritic molecule with tetrabutyl ammonium bromide (TBAB) as a cation inhibitor and dibutylphthalate (DBP), dioctylphthalate (DOP), dibutyl (butyl) phosphonate (DBBP) and 1-chloronaphthalene (CN) as plasticizing solvent mediators were prepared and used as nitrate ion-selective electrodes. Optimum performance was observed with the membrane having I-PVC-TBAB-DBP in the ratio 1:33:1:65 (w/w). The electrode has a linear response to nitrate with a detection limit of 3.9 × 10⁻⁵ ± 0.07 M and Nernstian compliance (57.0 ± 0.2 mV/decade) between pH 2.8 and 9.6 with a fast response time of about 20 s. The selectivity coefficient values of the order of 0.001 for mono-; bi- and trivalent anions; indicate high selectivity for nitrate ions over these anions. The preparation procedure of the electrode is very easy and inexpensive. The electrodes were used over a period of 45 days with good reproducibility. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of nitrate ions in waste water samples.     

Sonogashira coupling reactions of bromomaleimides: route to alkyne/cis-alkene/alkyl maleimides: synthesis of luffarin X and cacospongionolide C

Palladium-catalyzed Sonogashira coupling reaction of bromomaleimides with a diverse range of terminal alkynes has been demonstrated to furnish the corresponding alkynylmaleimides in very good yields. This coupling reaction followed by selective reduction of the triple bond to single bond have been utilized as the decisive steps to accomplish the first total synthesis of natural products (±)-luffarin X and (±)-cacospongionolide C.     

Heavy Metal Stress and Its Consequences on Exopolysaccharide (EPS)-Producing <Emphasis Type="Italic">Pantoea agglomerans</Emphasis>

Currently, the heavy metal pollution is of grave concern, and the part of microorganism for metal bioremediation should take into account as an efficient and economic strategy. On this framework, the heavy metal stress consequences on exopolysaccharide (EPS)-producing agricultural isolate, Pantoea agglomerans, were studied. The EPS production is a protective response to stress to survive and grow in the metal-contaminated environment. P. agglomerans show tolerance and mucoid growth in the presence of heavy metals, i.e., mercury, copper, silver, arsenic, lead, chromium, and cadmium. EDX first confirmed the metal accumulation and further, FTIR determined the functional groups involved in metal binding. The ICP-AES identified the location of cell-bound and intracellular metal accumulation. Metal deposition on cell surface has released more Ca²⁺. The effect on bacterial morphology investigated with SEM and TEM revealed the sites of metal accumulation, as well as possible structural changes. Each heavy metal caused distinct change and accumulated on cell-bound EPS with some intracellular deposits. The metal stress caused a decrease in total protein content and increased in total carbohydrate with a boost in EPS. Thus, the performance of P. agglomerans under metal stress indicated a potential candidate for metal bioremediation.

Open image in new window

Graphical Abstract ?

     

Efficient synthesis of protected l-phosphonophenylalanine (Ppa) derivatives suitable for solid phase peptide synthesis

l-Phosphonophenylalanine (Ppa) derivatives were synthesized from l-4-iodophenylalanine and suitably protected phosphites using Michaelis-Arbuzov reaction conditions in the presence of Pd(0) and triethylamine at 70 ± 2 °C.     

Structural,optical and electrical properties of tin oxide thin films by electrostatic spray deposition

Tin oxide (SnO₂) thin films were deposited by electrostatic spray deposition (ESD). The structural, optical and electrical properties of the films for different solvents were studied. The morphology of the deposited thin films was investigated by scanning electron microscopy. The optical transmission spectra of the films showed 66–75% transmittance in the visible region of spectrum. The electrical resistivity of thin films deposited using the different solvents ranged 1.08 × 10^?3–1.34 × 10^?3 Ω-cm. Overall, EG and PG were good solvents for depositing SnO₂ thin films by the ESD technique with stable cone jet.