Evaluation of antioxidant activity and DNA cleavage protection effect of naphthyl hydroxamic acid derivatives through conventional and fluorescence microscopic methods

Antioxidant capacity of N-(1-naphthyl)valerohydroxamic acid (NVHA) and N-(1-naphthyl)phenylacetohydroxamic acid (NPAHA) has been evaluated by a novel approach employing the fluorescence microscopic single molecule observation method. This method allows direct observation of the changes in single DNA molecules. The DNA cleavage protection activity of the compounds was also assessed by the gel electrophoresis method. The applied methods confirmed that both compounds are capable of inhibiting the free radical mediated DNA damage. Free radical scavenging activity was assessed via the 2,2′-diphenyl-1-picrylhydrazyl free radical (DPPH) and lipid peroxidation inhibition methods. The effective concentration causing a 50 % inhibition of the DPPH concentration, EC50, was found to be 371.54 mM for NVHA and 365.95 mM for NPAHA. Its lipid peroxidation inhibition ability was calculated to be 40.91 % at 371.54 mM for NVHA and 41.14 % at 365.95 mM for NPAHA. These results show the antioxidant potential of the naphthyl hydroxamic acids.     

Treatment of sugar processing industry wastewater using copper electrode by electrocoagulation: Performance and economic study

This paper demonstrates the use of copper electrode for the treatment of sugar processing industry wastewater (SPIW) in terms of chemical oxygen demand (COD) by applying electrocoagulation (EC) method. EC process was carried out in batch mode with electrode effective area of 0.0112 m², supplied current intensity (CI) of 44.64 A/m² - 223.21 A/m², electrode gap (EG) of 0.5–2.5 cm, electrolyte (NaCl) dose (ED) of 0.5–2.5 g/L to treat SPIW with initial chemical oxygen demand (COD) of 6000 mg/L. The maximum COD removal 73% of SPIW is achieved at optimized condition of SPIW pH: 7, CI: 89.28 A/m², EG: 1.5 cm & ED: 1.5 g/L. Sludge and scum generated during EC process were characterized by FTIR, TGA/DTA/DTG, proximate & ultimate analysis to find its applicability and their disposal. Additionally, economic study of EC treatment process at optimum condition suggest treatment cost was 11.2 US$/m³ and it indicate economic results as comparison to other available treatment processes.     

Discrimination between 2AP producing and non‐producing rice rhizobacterial isolates using volatile profiling: a chemometric approach

2‐Acetyl‐1‐pyrroline (2AP) is known as a principal basmati aroma compound. The present study aims at discriminating rhizobacteria isolated from soils cultivated with basmati and non‐basmati rice for long duration. Volatile profiling was used as marker to discriminate the rhizobacterial isolates. Quantification of 2AP and other volatile compounds (VCs) produced by rhizobacteria was undertaken using HS‐SPME coupled with GC‐MS. Chemometrics tools such as hierarchical cluster analysis (HCA), principle component analysis (PCA) and multi dimensional scaling (MDS) were applied for volatile profiling of different isolates. Results showed significant discrimination of all 2AP producing (AP‐P) and non‐producing rhizobacterial isolates (AP‐NP) on the basis of their VC profile. This was validated by bacterial identification data as well. The frequency distribution for 2AP levels indicates that basmati isolates had higher frequency for 2AP production as compared to non‐basmati control. AP‐P and AP‐NP isolates have different VC profiling pattern irrespective of their origin. These isolates were found belonging to different groups when identified using 16S rDNA sequencing data. Chemometric analysis (PCA, HCA and MDS) helped to identify volatiles, which could be used as biomarker in discriminating the AP‐P and AP‐NP isolates. VC pattern of rhizobacteria could be used as volatile markers to distinguish between AP‐P and AP‐NP rhizobacterial isolates. Copyright © 2015 John Wiley & Sons, Ltd.     

The effect of electric field stress on pure poly(vinyl chloride), poly(methyl methacrylate) and their polyblend samples

The TSDC and transient currents measurement have been carried out on pure poly(vinyl chloride), poly(methyl methacrylate) and polyblends of various weight ratios as a function of electric fields at constant poling temperature. For PVC and different blend samples single peak in the temperature range 100–170 °C has been observed in TSDC thermograms, however, for PMMA samples two peaks were observed at around 90 and 165 °C. The various TSDC parameters i.e. activation energy, charge released and relaxation times have been calculated. Results suggest that dipolar and space charge mechanism are dominant for observed current.     

CtrA gene based electrochemical DNA sensor for detection of meningitis

Electrochemical DNA sensor has been fabricated by immobilizing thiolated single stranded oligonucleotide (ssDNA) probe onto gold (Au) coated glass electrode for meningitis detection using hybridization with complementary DNA (CtrA) in presence of methylene blue (MB). These electrodes (ssDNA/Au and dsDNA/Au) have been characterized using atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), electrochemical impedance spectroscopy (EIS) and cyclic voltammetric (CV) technique. The DNA/Au electrode can detect the complementary DNA in the range of 7–42 ng/μl in 5 min (hybridization) with response time 60 s and electrode is stable for about 4 months when stored at 4 °C. The sensitivity of dsDNA/Au electrode is 115.8 μA/ng with 0.917 regression coefficient (R).     

Pancharatnam geometric phase originating from successive partial projections

The spin of a polarized neutron beam subjected to a partial projection in another direction, traces a geodesic arc in the 2-sphere ray space. We delineate the geometric phase resulting from two successive partial projections on a general quantal state and derive the direction and strength of the third partial projection that would close the geodesic triangle. The constraint for the three successive partial projections to be identically equivalent to a net spin rotation regardless of the initial state, is derived.      

Transient and thermally stimulated depolarization currents in pure and iodine doped polyvinyl formal (PVF) films

Transient currents, measured with pure and iodine doped polyvinyl formal (PVF) films as a function of poling field (15–100 kV/cm) and temperature (30–95°C), have been found to follow Curie-von Schweidler law characterized with two slopes in short and long time regions. The isochronals (i.e. current/temperature plots at constant times) have been found to give rise to a peak located at 75°C. The order of current has been found to increase with increase in poling field, temperature and iodine mixing. The comparative studies of the isochronals with the thermally stimulated discharge current (TSDC) indicated the strong resemblance between the two studies. It is suggested that both the dipolar orientation due to molecular mechanism of motions with the side chains and space charge due to trapping of injected charge carriers in energetically distributed traps may be responsible for the observed currents. The dependence of current and activation energy on iodine mixing is explained on the basis of a charge transfer type of interaction.     

Magnetic phase diagram of double-layered La2−2xCa1+2xMn2O7 manganite

Double-layered manganite La_2−2xCa_1+2xMn₂O₇ have been synthesized for compositions ‘x’=0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 by solid state reaction method. From X-ray diffraction study, their crystal structures were found to be tetragonal perovskite with lattice parameters decreasing with increasing ‘x’. The decreasing lattice parameters affect the balance between in-plane, intra-bilayer and inter-bilayer exchange interactions, which is reflected on magnetotransport properties. The metal-to-insulator transition temperature is found to vary with composition and peaked around ‘x’=0.3. From ac-susceptibility study, 2D-ferromagnetic ordering was observed at higher temperatures for all compositions whereas 3D-ferromagnetic ordering was observed at quite low temperatures. In low-temperature region, decreasing susceptibility shows antiferromagnetic state for all compositions. On the basis of electrical and magnetic properties, a magnetic phase diagram is given.     

Temperature dependence of electroresistance for La0.67Ba0.33MnO3 manganite

The influence of dc biasing current on temperature dependence of resistance of La_0.67Ba_0.33MnO₃ bulk sample is reported. A decrease in the resistance (electroresistance) on the application of higher bias current is observed. The electroresistance is maximum at metal-insulator transition temperature (T_MI) and decreases when the temperature is either increased or decreased from T_MI. A two-phase model is proposed to explain the occurrence of electroresistance. The higher bias current leads to an increase in alignment of spins and thus, in turn, leads to an increase in spin stiffness coefficient and decrease in the resistance at T_MI.