Flavonoid and leaf gas exchange responses of Centella asiatica to acute gamma irradiation and carbon dioxide enrichment under controlled environment conditions

The study was couducted to investigate the effects of gamma irradiation and CO? on flavonoid content and leaf gas exchange in C.asiatica. For flavonoid determination, the design was a split split plot based on Randomized Complete Block Design (RCBD). For other parameters, the designs were split plots. Statistical tests revealed significant differences in flavonoid contents of Centella asiatica leaves between different growth stages and various CO? treatments. CO? 400, G20 (400 = ambient CO?; G20 = Plants exposed to 20 Gy) showed 82.90% higher total flavonoid content (TFC) in the 5th week than CO? 400 as control at its best harvest time (4th week). Increasing the concentration of CO? from 400 to 800 μmol/mol had significant effects on TFC and harvesting time. In fact, 800 μmol/mol resulted in 171.1% and 66.62% increases in TFC for control and irradiated plants, respectively. Moreover, increasing CO? concentration reduced the harvesting time to three and four weeks for control and irradiated plants, respectively. Enhancing CO? to 800 μmol/mol resulted in a 193.30% (CO? 800) increase in leaf biomass compared to 400 μmol/mol and 226.34% enhancement in irradiated plants (CO? 800, G20) [800 = Ambient CO?; G20 = Plants exposed to 20 Gy] than CO? 400, G20. In addition, the CO? 800, G20 had the highest amount of flavonoid*biomass in the 4th week. The results of this study indicated that all elevated CO? treatments had higher PN than the ambient ones. The findings showed that when CO? level increased from 400 to 800 μmol/mol, stomatal conductance, leaf intercellular CO? and transpiration rate had the tendency to decrease. However, water use efficiency increased in response to elevated CO? concentration. Returning to the findings of this study, it is now possible to state that the proposed method (combined CO? and gamma irradiation) has the potential to increase the product value by reducing the time to harvest, increasing the yield per unit area via boosting photosynthesis capacity, as well as increasing biochemicals (flavonoids) per gram DM.     

Molecular spectroscopic analyses of gelatin

The molecular structure of gelatin was studied using Fourier transform infrared spectroscopy FTIR. The spectrum is subjected to deconvolution in order to elucidate the constituents of the molecular structure. B3LYP/6-31g** was used to study 13 amino acids then the scaled spectrum was compared to those of protein in order to describe the contribution of each amino acid into protein structure. A special interest was paid to the NH and C=O region. The reactivity of each amino acid was studied in terms of some important physical parameters like total dipole moment and HOMO/LUMO which describe the interaction of amino acid with their surrounding molecules. Results indicated that B3LYP/6-31g** model is a suitable and precise method for studying molecular structure of protein.     

Mono and binuclear Ag(I), Cu(II), Zn(II) and Hg(II) complexes of a new azo-azomethine as ligand: synthesis, potentiometric, spectral and thermal studies

New azo-azomethine dyes were prepared by reaction of p-aminobenzoic acid, o-anisidine, o-nitroaniline, and p-bromoaniline with salicylaldehyde respectively to form azo compounds and then condensation by urea to form 4-(R-arylazo 2-salicylaldene)-urea azo-azomethine derivatives (I(a-d)). The complexes of these ligands with Ag(I), Cu(II), Zn(II) and Hg(II) metal ions were prepared. The structure of the free ligands and their complexes were characterized by using elemental analysis (C, H, N), (1)H NMR, IR and UV-Vis-spectra. The proton dissociation constants of the ligands and the stability constant of their complexes have been determined potentiometrically in 40% (v/v) alcohol-water medium as well as the stoichiometry of complexes were determined conductometrically. The data reveal that the stoichiometries for all complexes were prepared in molar ratios (1:1) and (1:2) (M:L). The electrolytic and nonelectrolytic natures of the complexes were assigned based on molar conductance measurements. The thermogravimetric (TG), and differential thermal analyses (DTA) were studied in nitrogen atmosphere with heating rate 10°C/min. The kinetic and thermodynamic parameters for thermal decomposition of complexes have been calculated by graphical method using Coats-Redfern (CR) method.     

Centers of quasi-homogeneous polynomial differential equations of degree three

We characterize the centers of the quasi-homogeneous planar polynomial differential systems of degree three. Such systems do not admit isochronous centers. At most one limit cycle can bifurcate from the periodic orbits of a center of a cubic homogeneous polynomial system using the averaging theory of first order.     

Ternary paddlewheel copper(II) complexes: synthesis,structural elucidation,DNA-binding,anti-oxidant and conductance studies

ABSTRACT

Two new binuclear Cu(II) complexes Cu₂L₄(DMS)₂ (1) and Cu₂L₄(3BrPy)₂ (2) where L = para-chlorophenyl acetate, DMS = dimethylsulfoxide and 3BrPy = 3-bromopyridine have been synthesised and characterised using FT-IR, single crystal XRD analysis, absorption and conductance studies. In both the complexes copper(II) ion lies in distorted square pyramidal geometry where the apical position is occupied by pyridine in monodentate fashion while the equatorial positions are occupied by four carboxylate ligands in bidentate coordination mode. The supramolecular structures of the complexes arise primarily as a result of C–H…O and H–C…H types of interactions and are different owing to the different apical ligands. The DNA-binding activity of the complexes has been studied through absorption spectroscopy, viscometry and competitive ethidium bromide displacement techniques. These techniques indicated a mixed electrostatic and intercalative mode of interaction with DNA-binding constant values K_b of 1.98 × 10⁴ M^?1 and 2.86 × 10⁴ M^?1 for complexes 1 and 2, respectively. These activities represent the preliminary biological relevance of the synthesised complexes.     

Synthesis of novel spiro(indolone‐3,2′‐[1,3,4]thiadiazol)‐2‐ones and evaluation of their antidepressant and anticonvulsant activities

The reaction of 3‐(dicyanomethylene)‐2‐indolone in a solution of ethanol/piperidine with 4‐substituted thiosemicarbazides forms the derivatives of 5′‐(substituted amino)‐3′H–spiro(indoline‐3,2′‐[1,3,4]thiadiazol‐2‐one. Rationales for these conversions involving the nucleophilic addition on the dicyanomethylene carbon atom are presented. The prepared compounds were evaluated each for antidepressant activity using tail suspension behavioral despair test and anticonvulsant activity against pentylenetetrazol induced seizures in mice. J. Heterocyclic Chem., (2011).     

Comparative study of heavy metal and trace element accumulation in edible tissues of farmed and wild rainbow trout (Oncorhynchus mykiss) using ICP-OES technique

The objective of this research was to determine the differences between farmed and wild rainbow trout in terms of heavy metal and trace element accumulation in edible tissues. The samples were analyzed for As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, Sr and Zn by inductively coupled plasma-optical emission spectrometry (ICP-OES); and for Hg by cold vapor atomic absorption spectrometry (CVAAS). The results were expressed as μg/g of dry weight. With the exception of Ba and Sr, liver had significantly higher heavy metal and trace element concentrations compared to the muscle in farmed or wild fish. Higher levels of Ba, Cr, Fe, Mn and Zn, as well as lower levels of Cu and Sr were found in tissues of wild rainbow trout compared to its farmed relative. Levels of Cd in 41.6% of farmed fish samples and 45.8% of wild fish samples exceeded the European Commission regulation. Regarding the Pb, concentrations in 50% of farmed fish samples and 62.5% of wild ones were above the European Commission limit. However, levels of Hg and As in all of the examined samples were lower than the legislated limits. The differences in heavy metal and trace element accumulation observed between farmed and wild fish were probably related to the differences in their environmental conditions and dietary element concentrations.     

Hydrothermal low-temperature preparation and characterization of ZnO nanoparticles supported on natural zeolite as a highly efficient photocatalyst

Abstract  

Nanoparticles of zinc oxide were supported on natural zeolite using a hydrothermal method. The catalyst was characterized by X-ray diffraction, UV–vis diffuse reflectance spectra, scanning electron microscopy, and energy-dispersive X-ray techniques. The maximum rate constant for photodegradation of methylene blue (MB) was observed at 80 wt.% ZnO. The influence of various parameters such as catalyst composition, initial concentration of MB, calcination temperature, pH, and catalyst weight on the photodegradation reaction was studied. It was found that photodegradation of MB followed pseudo-first-order kinetics. The rate constant of the reaction for 80 wt.% ZnO at optimized conditions was approximately 3.8 times higher than that for bare ZnO. The photocatalyst had good reusability after four runs. The higher activity of the supported catalyst is due to greater adsorption of MB on the catalyst and its capability to delocalize the conduction-band electrons of excited ZnO.     

Evidence of superparamagnetic co clusters in pulsed laser deposition-grown Zn0.9Co0.1O thin films using atom probe tomography

Nanosized Co clusters (of about 3 nm size) were unambiguously identified in Co-doped ZnO thin films by atom probe tomography. These clusters are directly correlated to the superparamagnetic relaxation observed by ZFC/FC magnetization measurements. These analyses provide strong evidence that the room-temperature ferromagnetism observed in the magnetization curves cannot be attributed to the observed Co clusters. Because there is no experimental evidence of the presence of other secondary phases, our results reinforce the assumption of a defect-induced ferromagnetism in Co-doped ZnO diluted magnetic semiconductors.