EFFECTS OF PLANT EXTRACTS ON ARYL HYDROCARBON HYDROXYLASE ACTIVITY AND 3H-BENZO(a)PYRENE BINDING TO DNA

Eight plant species belonging to different families were extracted and fractionated by organic solvents and their total extracts were tested against aryl hyrocarbon hydroxylase (AHH) activity and ³H-benzo(a)pyrene binding to DNA in vitro. The n-butanol extract was more effective than the extracts of chloroform and petroleum-ether, respectively. None of the aqueous extracts showed any inhibitory effects on both AHH activity and ³H-benzo(a)pyrene binding to DNA. The extracts obtained from Cypressus sempevirens L., Anchusa strigosa L., Myrtus communis L., and Crataegus monogyna L. were more effective than the extracts from Achillea santolina L. and Thuja occidentalis L. However, extracts obtained from Adiantum capillus-veneris L. and Salsola rosamarinus L. exhibited no effects. The results suggest that the inhibitory effects of these plant extracts on AHH activity and ³H-benzo(a)pyrene binding to DNA might have similar effect in vivo and there might be used in the prevention of cancer .     

ANTIMUTAGENIC ACTIVITIES OF PHENOLIC PLANT FLAVONOIDS

Total phenolic plant flavonoids obtained from Thuia accidentalis L. and Cupressus sempevirens L. showed antimutagenic effects on benzo(a) pyrene [B(a)P] in Salmonella typhimurium strains TA100 and TA98. The n-butanol extract was more effective then chloroform and petrol eum-ether extracts, respectively. Aqueous extracts exhibited no inhibition in both strains. Total flavonoids from C. sempevirens showed more antimutagenic activity than flavonoids from T. accidentalis. None of the extracts revealed any cytotoxic or mutagenic activity on the bacterial tester strains.     

Artificial neural networks for prediction of percentage of water absorption of geopolymers produced by waste ashes

In the present work, percentage of water absorption of geopolymers made from seeded fly ash and rice husk bark ash has been predicted by artificial neural networks. Different specimens, made from a mixture of fly ash and rice husk bark ash in fine and coarse form together with alkali activator made of water glass and NaOH solution, were subjected to permeability tests at 7 and 28 days of curing. The curing regime was different: one set cured at room temperature until reaching to 7 and 28 days and the other sets were oven cured for 36 h at a range of 40–90 °C and then cured at room temperature for 7 and 28 days. To build the model, training and testing using experimental results from 120 specimens were conducted. According to these input parameters, in the neural networks model, the percentage of water absorption of each specimen was predicted. The training and testing results in the neural networks model have shown a strong potential for predicting the percentage of water absorption of the geopolymer specimens.     

Preparation, characterization and photocatalytic activity of TiO2/polyaniline core-shell nanocomposite

Polyaniline (PANI) as a promising conducting polymer has been used to prepare polyaniline/TiO₂ (PANI/TiO₂) nanocomposite with core-shell structure as photocatalyst. Titanium dioxide (TiO₂) nanoparticles with an average crystal size of 21?nm were encapsulated by PANI via the in situ polymerization of aniline on the surface of TiO₂ nanoparticles. FT?CIR, UV-Vis-NIR, XRD, SEM and TEM techniques were used to characterize the PANI/TiO₂ core-shell nanocomposite. Photocatalytic activity of PANI/TiO₂ nanocomposite was investigated under both UV and visible light irradiations and compared with unmodified TiO₂ nanoparticles. Results indicated deposition of PANI on the surface of TiO₂ nanoparticles which improved the photocatalytic activity of pristine TiO₂ nanoparticles.     

New approach for solving intuitionistic fuzzy multi-objective transportation problem

Multi-objective transportation problem (MOTP) under intuitionistic fuzzy (IF) environment is analysed in this paper. Due to the fluctuation of market scenario, we assume that the transportation cost, the supply and the demand parameters are not always precise. Hence, the parameters are imprecise, i.e., they are IF numbers. Considering the specific cut interval, the IF transportation cost matrix is converted to interval cost matrix in our proposed problem. Again, using the same concept, the IF supply and the IF demand of the MOTP are reduced to the interval form. Then the proposed MOTP is changed into the deterministic MOTP, which includes interval form of the objective functions. Two approaches, namely intuitionistic fuzzy programming and goal programming, are used to derive the optimal solutions of our proposed problem, and then the optimal solutions are compared. A numerical example is included to illustrate the feasibility and the applicability of the proposed problem. Finally, we present the conclusions with the future scopes of our study.     

Electrochemical,surface analytical and quantum chemical studies on Schiff bases of 4-amino-4H-1, 2, 4-triazole-3,5-dimethanol (ATD) in corrosion protection of aluminium in 1N HNO<Subscript>3</Subscript>

The present study describes the inhibition of aluminium in 1N HNO₃ with different concentrations of 1,2,4-triazole precursors ATD, BATD and DBATD using gravimetric method, potentiodynamic polarization studies (Tafel), electrochemical impedance spectroscopy (EIS), adsorption studies, surface morphological studies and quantum chemical calculations at 298 K. Polarization studies clearly showed that ATD, BATD and DBATD act as mixed type inhibitors. As the electron density around the inhibitor molecule increases due to substitution, the inhibition efficiency also increases correspondingly. Quantum chemical approach was used to calculate some electronic properties of the molecule to ascertain the correlation between inhibitive effect and molecular structure of the inhibitor. The corrosion inhibition efficiencies of these molecules and the global chemical reactivity relate to some parameters, such as E _HOMO , E _LUMO , gap energy (ΔE), electronegativity (χ), global hardness (η) and the fraction of electrons transferred from the inhibitor molecule to the metallic atom (DNDelta emph{N}). In addition, the local reactivity has been analysed through the Fukui function and condensed softness indices. Both the experimental and theoretical studies agree well in this regard and confirm that DBATD is a better inhibitor than BATD and ATD. The adsorption behaviours of molecules on the copper surface have been studied using molecular dynamics method and density functional theory. The order of inhibitory action is DBATD > BATD > ATD.     

Fatigue crack growth of filled rubber under constant and variable amplitude loading conditions

Service conditions experienced by rubber components often involve cyclic loads which are more complex than a constant amplitude loading history. Consequently, a model is needed for relating the results of constant amplitude characterization of fatigue behaviour to the effects of variable amplitude loading signals. The issue is explored here via fatigue crack growth experiments on pure shear specimens conducted in order to evaluate the applicability of a linear crack growth model equivalent to Miner's linear damage rule. This model equates the crack growth rate for a variable amplitude signal to the sum of the constant amplitude crack growth rates associated with each individual cycle. The variable amplitude signals were selected to show the effects of R-ratio (ratio of minimum to maximum energy release rate), load level, load sequence, and dwell periods on crack growth rates. In order to distinguish the effects of strain crystallization on crack growth behaviour, two filled rubber compounds were included: one that strain crystallizes, natural rubber, and one that does not, styrene-butadiene rubber. The linear crack growth model was found to be applicable in most cases, but a dwell effect was observed that is not accounted for by the model.     

Quality Evaluation of Raw Tuna by Gas Chromatography and Sensory Methods

An objective method of evaluating raw tuna quality was developed based on the volatile profile pattern obtained by gas chromatography. Five component; of the volatile profile showed a significant correlation to the raw tuna quality evaluated organoleptically. A chemical quality index, (Q.I.) was developed on commercially available tuna using the concentration of five components: ethanol, propanol, butanol, hexanal, and 1–pentene–3–ol. Quality designation of raw tuna using the Q.I. index resulted in a more accurate classification than the orgganoleptic method.     

ANALYSIS OF TIME HEADWAYS ON URBAN ROADS

The headway between vehicles in a traffic stream is of fundamental importance in traffic engineering applications. Previous research in this subject has focused on modeling theoretical distributions for low and medium traffic flow conditions. Yet little research has studied congested traffic conditions, that is, the high traffic flow state. In the same context, there appears to be a lack of clear-cut boundaries for the three flow states (low, medium, and high). This study attempts to determine such boundaries on the basis of traffic conditions observed at the study sites. Although observed headways at arterial sites follow a gamma distribution, distributions that fit freeway headways differ according to the traffic flow state. The Erlang distribution provided a good fit to the observed headways at sites with high traffic flows.     

Comparison of Rapid Methods for isolation and Enumeration of Clostridium perfringens in Meat

Three strains of Clostridium pefringens, ATCC 12924, ATCC 12917, and ATCC 14809, were inoculated separately into thioglycollate broth and ground beef samples and enumerated by Fung's Double Tube (FDT), Oxyrase Enzyme (OE), Gas Pak Anaerobic System (GPAS), and Anaerobic Petri Dish (APD) methods. Recovery of the three strains by FDT was significantly higher (P < 0.05) than that by the other three methods from both thioglycollate broth and ground beef, with OE second highest. FDT gave better recovery (84%) in less time (8–10 hr) at 42°C compared with the OE method (61%). FDT was also least costly.