Abstract: Polycyclic aromatic hydrocarbons (PAHs) are formed
during the pyrolysis of scrap tyres to produce tyre pyrolytic oil
(TPO). Due to carcinogenic, mutagenic, and toxic properties PAHs
are priority pollutants. Hence it is essential to remove PAHs from
TPO before utilising TPO as a petroleum fuel alternative (to run the
engine). Agricultural wastes have promising future to be utilized as
biosorbent due to their cost effectiveness, abundant availability, high
biosorption capacity and renewability. Various low cost adsorbents
were prepared from natural sources. Uptake of PAHs present in tyre
pyrolytic oil was investigated using various low-cost adsorbents of
natural origin including sawdust (shisham), coconut fiber, neem bark,
chitin, activated charcoal. Adsorption experiments of different PAHs
viz. naphthalene, acenaphthalene, biphenyl and anthracene have been
carried out at ambient temperature (25°C) and at pH 7. It was
observed that for any given PAH, the adsorption capacity increases
with the lignin content. Freundlich constant Kf and 1/n have been
evaluated and it was found that the adsorption isotherms of PAHs
were in agreement with a Freundlich model, while the uptake
capacity of PAHs followed the order: activated charcoal> saw dust
(shisham) > coconut fiber > chitin. The partition coefficients in
acetone-water, and the adsorption constants at equilibrium, could be
linearly correlated with octanol–water partition coefficients. It is
observed that natural adsorbents are good alternative for PAHs
removal. Sawdust of Dalbergia sissoo, a by-product of sawmills was
found to be a promising adsorbent for the removal of PAHs present in
TPO. It is observed that adsorbents studied were comparable to those
of some conventional adsorbents.
Abstract: In this paper we report the quantitative structure activity relationship of novel bis-triazole derivatives for predicting the activity profile. The full model encompassed a dataset of 46 Bis- triazoles. Tripos Sybyl X 2.0 program was used to conduct CoMSIA QSAR modeling. The Partial Least-Squares (PLS) analysis method was used to conduct statistical analysis and to derive a QSAR model based on the field values of CoMSIA descriptor. The compounds were divided into test and training set. The compounds were evaluated by various CoMSIA parameters to predict the best QSAR model. An optimum numbers of components were first determined separately by cross-validation regression for CoMSIA model, which were then applied in the final analysis. A series of parameters were used for the study and the best fit model was obtained using donor, partition coefficient and steric parameters. The CoMSIA models demonstrated good statistical results with regression coefficient (r2) and the cross-validated coefficient (q2) of 0.575 and 0.830 respectively. The standard error for the predicted model was 0.16322. In the CoMSIA model, the steric descriptors make a marginally larger contribution than the electrostatic descriptors. The finding that the steric descriptor is the largest contributor for the CoMSIA QSAR models is consistent with the observation that more than half of the binding site area is occupied by steric regions.
Abstract: Verapamil has been shown to inhibit fentanyl uptake in vitro and is a potent P-glycoprotein inhibitor. Tissue partitioning of loperamide, a commercially available opioid, is closely controlled by the P-gp efflux transporter. The following studies were designed to evaluate the effect of opioids on verapamil partitioning in the lung and brain, in vivo. Opioid (fentanyl or loperamide) was administered by intravenous infusion to Sprague Dawley rats alone or in combination with verapamil and plasma, with lung and brain tissues were collected at 1, 5, 6, 8, 10 and 60 minutes. Drug dispositions were modeled by recirculatory pharmacokinetic models. Fentanyl slightly increased the verapamil lung (PL) partition coefficient yet decreased the brain (PB) partition coefficient. Furthermore, loperamide significantly increased PLand PB. Fentanyl reduced the verapamil volume of distribution (V1) and verapamil elimination clearance (ClE). Fentanyl decreased verapamil brain partitioning, yet increased verapamil lung partitioning. Also, loperamide increased lung and brain partitioning in vivo. These results suggest that verapamil and fentanyl may be substrates of an unidentified inward transporter in brain tissue and confirm that verapamil and loperamide are substrates of the efflux transporter P-gp.
Abstract: The study investigated the hydrophilic to hydrophobic
transition of modified polyacrylamide hydrogel with the inclusion of
N-isopropylacrylamide (NIAM). The modification was done by
mimicking micellar polymerization, which resulted in better
arrangement of NIAM chains in the polyacrylamide network. The
degree of NIAM arrangement is described by NH number. The
hydrophilic to hydrophobic transition was measured through the
partition coefficient, K, of Orange II and Methylene Blue in hydrogel
and in water. These dyes were chosen as a model for solutes with
different degree of hydrophobicity. The study showed that the
hydrogel with higher NH values resulted in better solubility of both
dyes. Moreover, in temperature above the lower critical solution
temperature (LCST) of Poly(N-isopropylacrylamide) (PNIAM)also
caused the collapse of NIPAM chains which results in a more
hydrophobic environment that increases the solubility of Methylene
Blue and decreases the solubility of Orange II in the hydrogels with
NIPAM present.
Abstract: This report focus on phase behavior of polyethylene glycol (PEG)4000/ phosphate/ guanidine hydrochloride/ water system at different guanidine hydrochloride concentrations and pH. The binodal of the systems was displaced toward higher concentrations of the components with increasing guanidine hydrochloride concentrations. The partition coefficient of guanidine hydrochloride was near unity and increased with decreasing pH and increasing PEG/salt (%w/w) ratio.