Antiferromagnetic Interaction in Mn(IV) Biguanide Complexes

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BIOSORPTION OF CHROMIUM (VI) BY A MUTATED STRAIN OF Bacillus cereus M116

The removal of chromium, a highly toxic metal causing environmental pollution from dilute aqueous solution, was studied in the present work using growing and washed cells of a mutant strain of Bacillus cereus (M116) isolated from tannery waste. Particularly, the effects of pH, temperature, metal ion concentration and contact time on removal of chromium werestudied. About 40% chromium removal, was observed by growing cells of the selected strain at pH 6.5, temperature 30o±1oC, inoculum size 3%, medium volume 50 ml/250 ml Erlenmeyer flask, and initial chromium concentration 50 ppm. Usingresting cells 98.02% and 78.34% chromium removal was possible with initial chromium concentration of 25 and 50 ppm, respectively, at pH 3.0, temperature 25-35oC and 2.73 g/L biomass concentration. It was found that the overall adsorption process was best described by pseudo-second order kinetics. Freundlich and Langmuir adsorption models were found suitablefor describing the short-term biosorption of chromium (VI). IR spectral analysis of the biomass was carried out to find out the functional groups responsible for chromium (VI) biosorption

Formation of a gold-carbon dot nanocomposite with superior catalytic ability for the reduction of aromatic nitro groups in water

We report the synthesis of a gold-carbon dot nanocomposite and its utility as a recyclable catalyst for the reduction of aromatic nitro groups. The presence of carbon dots on gold nanosurfaces enhanced the reduction rate by two-fold

Continuous removal of chromium from tannery wastewater using activated sludge process—Determination of kinetic parameters

32-36The activated sludge has been acclimatized with chromium (VI) ions from 5 mg/L to 20 mg/L. It is observed that the chromium removal percentage, COD removal and mixed liquor suspended solid (MLSS) decrease with the increase in dilution rate. Maximum food to microorganisms ratio (F/M) is found to be 0.19. When initial metal ion concentration increases from 5 mg/L to 20 mg/L, the chromium removal decreases from 95.58% to 63.85% (dilution rate 0.041h-1)

Adsorptive column studies for removal of Reactive Blue 4 dye using dry cells of Rhizopus oryzae (MTCC 262)

511-518The biosorption potential of dry biomass of Rhizopus oryzae (MTCC 262) in removing a textile dye Reactive Blue 4 from dye contaminated wastewater using up-flow packed-bed column reactor has been studied. The impact of operating parameters like flow rate of dye solution, bed height of column and concentration of dye in the feed solution on the removal potential has also been studied. The Adam-Bohart Model, Yoon-Nelson Model and Thomas model are used for the analysis of experimental data. Dye removal of 71.81% is obtained using dry biomass at flow rate of 2 mL min-1of dye solution, bed height of 15 cm and influent dye concentration of 200 mg L-1. Adsorbed dye can be successfully recovered from dry R.oryzae (MTCC 262) biomass of packed bed column reactor by running 1 (N) NaOH solution. Results demonstratesignificant reduction in Reactive Blue 4 concentration after the biosorption process

Absent ventriculo-atrial conduction during right ventricular apical pacing but nodal response during para-Hisian pacing – What is the mechanism?

A 13-year-old-girl presented with one episode of pre-syncope while standing in a train. Her ECG was suggestive of preexcitation. Echocardiography revealed structurally normal heart without any ventricular hypertrophy. During electrophysiology study, her ventriculo-atrial (VA) conduction was absent even on isoprenaline. However, a para-Hisian pacing maneuver (PHP) revealed consistent VA conduction with a nodal response. This finding indicated that the VA dissociation at baseline was at infra-Hisian (VH) level and conduction at HA level was intact. In addition, this finding is coherent with a speculation of a fasciculo-ventricular pathway (FVP) resulting in such an ECG pattern in her. Pacing from various atrial sites (right atrium, coronary sinus) exhibited nearly fixed preexcitation and short non-varying HV interval confirmatory of FVP. Testing for a PRKAG mutation was advised for her

An unusual genetic observation in a case of short-coupled PVC-triggered ventricular fibrillation

Ventricular fibrillation induced by short-coupled premature ventricular complex is an uncommon cause of cardiac arrest in young individuals with no structural heart disease. The genetic substrate of this condition is heterogeneous and remains incompletely defined. We describe a case of short-coupled premature ventricular complex-triggered ventricular fibrillation with a likely pathogenic variant in the titin (TTN) gene. (Level of Difficulty: Advanced.)