Equilibrium studies on sorption of an anionic dye onto acid activated water hyacinth roots

The inappropriate disposal of dyes in wastewater constitutes an environmental problem and can cause damage to the ecosystem. Present investigation deals with the utilization of water hyacinth roots (collected from the ponds) as adsorbent for the removal of anionic dye from its aqueous solutions. Batch studies were conducted to evaluate the adsorption capacity of the dye, Congo red on the sorbent with respect to the variations in initial pH, contact time and initial dye concentration and the adsorbent. The effective pH for better adsorption of Congo red on water hyacinth roots was found to be 6.0. Equilibrium was reached in about 3 h contact time. Equilibrium isotherms for the adsorption of Congo red on water hyacinth root were analyzed by the Freundlich, Langmuir and Redlich–Peterson isotherm equations. Results showed that Redlich–Peterson isotherm best-fits with the Congo red adsorption isotherm data on all initial dye concentrations. The Freundlich isotherm also showed comparable fit

Optimization of Inulinase Production from Garlic by Streptomyces sp. in Solid State Fermentation Using Statistical Designs

Plackett-Burman design was employed for screening 18 nutrient components for the production of inulinase using Garlic as substrate by Streptomyces sp. in solid-state fermentation (SSF). From the experiments, 4 nutrients, namely, NH4NO3, MnSO4·7H2O, Soya bean cake, and K2HPO4 were found to be most significant nutrient components. Hence, these 4 components are selected. The selected components were optimized using response surface methodology (RSM). The optimum conditions are NH4NO3—6.63 mg/gds, MnSO4·7H2O—26.16 mg/gds, Soya bean cake—60.6 mg/gds, and K2HPO4—5.24 mg/gds. Under these conditions, the production of inulinase was found to be 76 U/gds

Kinetic Modeling and Effect of Process Parameters on Selenium Removal Using Strong Acid Resin

Heavy metal pollution due to the contamination of Selenium above the tolerable limit in the natural environment is a challenging issue that environmental scientists face. This study is aimed at identifying ion exchange technology as a feasible solution to remove selenium ions using 001x7 resin. Parametric experiments were conducted to identify the optimal pH, sorbent dose and speed of agitation. Selenium removal efficiency of 85% was attained at pH 5.0 with 100 mg/L selenium concentration. The increase in resin dose was found to increase removal efficiency. However, metal uptake decreased. The experiments on the effect of concentration proved the negative effect of higher concentrations of selenium on removal efficiency. The ion exchange process was proved to be optimal at an agitation speed of 200 rpm and a temperature of 35 °C. Pseudo second order model was found to fit the kinetic data very well compared to the pseudo-first order model and the pseudo second order rate constant was estimated as 8.725x10-5 g mg-1 min-1 with a solution containing 100 mg/L selenium

OPTIMIZATION OF INULINASE PRODUCTION USING COPRA WASTE BY Kluyveromyces marxianus var. marxianus

Kluyveromyces marxianus var. marxianus was found to secrete a large amount of extracellular inulinase in to the medium. The optimization of inulinase pro¬duction using copra waste as a carbon source was performed with statistical methodology based on experimental designs. The screening of eighteen nut¬rients for their influence on inulinase production was achieved using a Plackett––Burman design. Corn steep liquor, (NH4)2SO4, ZnSO47H2O, K2HPO4 and urea were selected based on their positive influence on inulinase production. The selected components were optimized using response surface methodology (RSM). The optimum conditions are: corn steep liquor – 0.0560 (g/gds), (NH4)2SO4 – 0.0084 (g/gds), ZnSO47H2O – 0.0254 (g/gds), K2HPO4 – 0.0037 (g/gds) and urea - 0.02147 (g/gds). These conditions were validated experimentally which revealed an enhanced inulinase yield of 372 U/gds

NANOCOMPOSITE APPLICATION FOR SELENIUM REMOVAL – PARAMETRIC STUDIES AND KINETIC MODELING

Nano composite material was synthesized using calcium hydroxy apatite and Phoenix Dactlyifera tree powder using wet chemical precipitation method and characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. The influence of operating parameters namely initial pH (3 -11), selenium concentration (50 -200 mg L-1 ), nanocomposite dose (0.5 - 6.0 g L-1 ), presence of competitor chloride ion (0 -10 g L-1 ) and agitation speed (0 – 600 rpm) on the metal uptake was studied. A correlation relating nano composite dose and selenium uptake was proposed as selenium uptake = 202.3 (e-0.259* nanocomposite dose) he maximum uptake capacity of the nanocomposite was found to be 57.27 mg g-1 under optimal environmental conditions with an initial selenium concentration of 100 mg L-1 . Monolayer sorption mechanism, proposed by Langmuir isotherm, was found to apply for this process and the isotherm constants were determined. Modified Ritchie second order and pseudo second order models were fitted to the experimental data and pseudo second order model correlated well with rate constant of 1.5 x 10-3 g mg-1 min-1 and maximum uptake capacity of 70.92 mg g-1 at 32 °C with 100 mg L-1 initial metal concentration. Ritchie model rate constant was evaluated as 1.41×10-2 min-1 under similar process conditions

CNS activity of Pokeweed Anti-viral Protein (PAP) in mice infected with Lymphocytic Choriomeningitis Virus (LCMV)

BACKGROUND: Others and we have previously described the potent in vivo and in vitro activity of the broad-spectrum antiviral agent PAP (Pokeweed antiviral protein) against a wide range of viruses. The purpose of the present study was to further elucidate the anti-viral spectrum of PAP by examining its effects on the survival of mice challenged with lymphocytic choriomeningitis virus (LCMV). METHODS: We examined the therapeutic effect of PAP in CBA mice inoculated with intracerebral injections of the WE54 strain of LCMV at a 1000 PFU dose level that is lethal to 100% of mice within 7–9 days. Mice were treated either with vehicle or PAP administered intraperitoneally 24 hours prior to, 1 hour prior to and 24 hours, 48 hours 72 hours and 96 hours after virus inoculation. RESULTS: PAP exhibits significant in vivo anti- LCMV activity in mice challenged intracerebrally with an otherwise invariably fatal dose of LCMV. At non-toxic dose levels, PAP significantly prolonged survival in the absence of the majority of disease-associated symptoms. The median survival time of PAP-treated mice was >21 days as opposed to 7 days median survival for the control (p = 0.0069). CONCLUSION: Our results presented herein provide unprecedented experimental evidence that PAP exhibits antiviral activity in the CNS of LCMV-infected mice

Time-Series Photometry of M67: W UMa Systems, Blue Stragglers, and Related Systems

We present an analysis of over 2200 V images taken on 14 nights at the Mt. Laguna 1 m telescope of the open cluster M67. Our observations overlap but extend beyond the field analyzed by Gilliland et al. (1991), and complement data recently published by van den Berg et al. (2002) and Stassun et al. (2002). We show variability in the light curves of all 4 of the known W UMa variables on timescales ranging from a day to decades (for AH Cnc). We have modeled the light curve of AH Cnc, and the total eclipses allow us to determine q = 0.16 +0.03/-0.02 and i = 86 +4/-8 degrees. The position of this system near the turnoff of M67 makes it useful for constraining the turnoff mass for the cluster. We have also detected two unusual features in the light curve of AH Cnc that may be caused by prominences. We have also monitored cluster blue stragglers for variability, and we present evidence hinting at low level variations in the stragglers S752, S968, and S1263, and we place limits on the variability of a number of other cluster blue stragglers. Finally, we provide photometry of the sub-subgiant branch star S1063 showing variability on timescales similar to the orbital period, while the ``red straggler'' S1040 shows evidence of an unexplained drop in brightness at phases corresponding to the passage of the white dwarf in front of the giant.Comment: 44 pages, 16 figures, AASTeX, accepted for A

Role of the Two Component Signal Transduction System CpxAR in Conferring Cefepime and Chloramphenicol Resistance in Klebsiella pneumoniae NTUH-K2044

Background: Klebsiella pneumoniae is a Gram-negative, non-motile, facultative anaerobe belonging to the Enterobacteriaceae family of the c-Proteobacteria class in the phylum Proteobacteria. Multidrug resistant K. pneumoniae have caused major therapeutic problems worldwide due to emergence of extended-spectrum b-lactamase producing strains. Twocomponent systems serve as a basic stimulus-response coupling mechanism to allow organisms to sense and respond to changes in many different environmental conditions including antibiotic stress. Principal Findings: In the present study, we investigated the role of an uncharacterized cpxAR operon in bacterial physiology and antimicrobial resistance by generating isogenic mutant (DcpxAR) deficient in the CpxA/CpxR component derived from the hyper mucoidal K1 strain K. pneumoniae NTUH-K2044. The behaviour of DcpxAR was determined under hostile conditions, reproducing stresses encountered in the gastrointestinal environment and deletion resulted in higher sensitivity to bile, osmotic and acid stresses. The DcpxAR was more susceptible to b-lactams and chloramphenicol than the wild-type strain, and complementation restored the altered phenotypes. The relative change in expression of acrB, acrD, eefB efflux genes were decreased in cpxAR mutant as evidenced by qRT-PCR. Comparison of outer membrane protein profiles indicated a conspicuous difference in the knock out background. Gel shift assays demonstrated direct binding of CpxR KP to promoter region of ompC KP in a concentration dependent manner

Diets containing sea cucumber (Isostichopus badionotus) meals are hypocholesterolemic in young rats

Peer reviewedPublisher PD