Intragenomic 16S rRNA gene heterogeneity in Lactococcus lactis subsp. cremoris

Partial 16S rRNA gene sequencing of Lactococcus lactis subsp. cremoris strains from our collection identified strains containing sequences diagnostic of both subspecies L. lactis subsp. lactis and L. lactis subsp. cremoris together in the same strain. The presence of a plasmid-encoded 16S rRNA pseudogene partly explained this result. Twenty-four out of 46 L. lactis subsp. cremoris strains tested by PCR contained this pseudogene. However, further analysis showed that five of these 24 strains also contained chromosomal 16S rRNA genes with sequences typical of L. lactis subsp. lactis. Genetic and phenotypic tests indicated these strains were otherwise normal L. lactis subsp. cremoris strains. Past recombination events between the 16S rRNA pseudogene and chromosomal 16S rRNA genes may explain this phenomenon. Genomic heterogeneity for both 16S rRNA and other gene sequences was observed for L. lactis subsp. cremoris SK11 from different laboratories, indicating caution is needed when integrating data from diverse sources for nominally the same strain.     

Determination of residues of trichlorfon and dimethoate on guava using HPLC

A supervised trial was conducted in guava orchards during 2001 and 2002 to study residue dissipation rates of two organophos insecticides, trichlorfon and dimethoate at Kohat, NWFP, Pakistan. The insecticides were sprayed at recommended doses of 80 and 120 g a.i./100 l water on the fruits of guava when the fruits were semi ripe. The treated guava fruits were randomly sampled in triplicates (2 kg per field replicate) at 0, 3, 7, 14, and 21 days intervals after insecticide application. The samples were extracted in ethyl acetate and were cleaned up through Florisil column with ethyl acetate as eluent. The cleaned up extracts were analyzed for residues by HPLC method. The residues were found to have half-lives of 2.8–3.3 days for dimethoate and 1.7–2.0 days for trichlorfon. Based on the dissipation pattern of the insecticide residues in relation to their respective prescribed maximum residue limits, withholding periods of 3 and 9 days are suggested for guava after treatment with dimethoate and trichlorfon.     

Trinary magnitude comparator using SLM based Savart plate

The demand of present technology inviting the popularity of multivalued optical computation system to coup up with the latest scenario of ultrahigh processing speed and handling large amount of data The magnitude comparator is the heart of the arithmetic and logic unit (ALU) in any logical processing and computing system. In this paper, a trinary magnitude comparator circuit has been proposed and implemented with modified trinary number (MTN) system. Optical tree architecture (OTA) of the proposed circuit has been realized reasonably using Savart plate and spatial light modulators (SLM). A simulation algorithm has also been developed and implemented to prove the authenticity of the proposed circuit through the simulation.     

Solvent refining of heavy wax distillate for the removal of carcinogenic compounds

Neat ethylacetoacetate (EAA) and its mixtures with a co-solvent and an anti-solvent have been studied for refining of heavy wax distillate fraction to produce substantially non-carcinogenic base oil. The co-solvent and anti-solvent used are dipropylene glycol (DPG) and ethylene glycol (EG) respectively. The solubility characteristics of the main solvent and its mixed solvent systems were studied. Selection of the optimum solvent mixture and extraction variables has been studied. The effect of co-solvent and anti-solvent addition on the carcinogenic potential and raffinate quality has been determined under clearly comparable conditions.     

Dielectric and Magnetodielectric Properties of R2NiMnO6 (R = Nd,Eu, Gd,Dy, and Y)

We have prepared polycrystalline R₂NiMnO₆ (R = Nd, Eu, Gd, Dy, and Y) samples by conventional solid‐state reaction and all the samples have shown monoclinic structure with P2₁/n space group. With the decrease in rare‐earth ionic size (<r_R>), the <Ni–O–Mn> bond angle decreases, correspondingly a decrease in ferromagnetic (FM) Curie temperature is noticed. In the dielectric measurement, the dielectric anomaly shifts to high temperature with the decrease in the <r_R> and shows no correlation with the FM Curie temperature and hints the absence of apparent magnetodielectric (MD) coupling. Appearance of multiple relaxations in the dielectric study suggests the electrical heterogeneity of the system. The dielectric/impedance analysis has revealed a close correlation between dc conductivity and the dielectrics; in fact, both dc resistivity and the grain relaxations follow the variable range hopping mechanism. The thermal activation of charge carriers at the grain boundary led to Maxwell–Wagner interfacial polarization. Finally, dielectric study under magnetic field showed no effect, it implies that not only the intrinsic MD is absent, but also the extrinsic MD due to the lack of magnetoresistance.     

Ferrocene-Based Cationic Surfactants: Surface and Antimicrobial Properties

A novel series of ferrocenyl surfactants was synthesized by the reaction of ferrocene disulfonic acid with different primary and tertiary fatty amines to produce the corresponding ammonium salts Fc[SO₃ ^{− +}NH₃(CH₂) _n CH₃]₂, where n = 9, 11, or 15 and Fc[SO₃^{− +}NH(CH₃)₂(CH₂) _n CH₃]₂, where n = 7 or 11, respectively, and where Fc = ferrocene. Chemical structures were confirmed by microelemental analysis, FTIR, and ¹H NMR spectroscopy. The critical micelle concentration of each prepared surfactant was determined using equilibrium surface tension. Furthermore, air/water interface parameters including effectiveness (π _CMC), efficiency (Pc₂₀), maximum surface excess (Г_max), and minimum surface area (A _min) were determined at 30, 40, and 50 °C. Thermodynamic parameters (ΔG°, ΔS°, and ΔH°) for both micellization and adsorption processes were recorded. The new synthesized surfactants were screened as antimicrobial agents against different bacterial and fungal organisms.