THE VERSATILITY OF SPIROPYRAN AS MULTIRESPONSIVE COMPOUND
Photoresponsive is a highly important system that leads to the development of photo-optical media, photo-switches, photo-mechanical systems, micropatterning, and non-linear optical media. It delivers external signals upon the irradiation of UV or visible light, which also can be reversed to original state. Spiropyrans is one of well-known group of photoresponsive compound, whose properties have been studied extensively. They are able to undergo conversion from closed spiropyran to open zwitterions merocyanine. The current concept of applying the SP as molecular switch is based on the overall consistency of reversibility, rapid response time and less interference. The adherence to those properties is therefore can lead to potential molecular devices, sensors and fluorescent switches. Therefore this review discussed on the background, external effects and the potential applications of photoresponsive spiropyran compounds.
TO DECONTAMINATE WASTEWATER EMPLOYING BIOREMEDIATION TECHNOLOGIES
Bioremediation is an ecologically sound and state-of-the-art technique that employs natural biological processes employing microorganisms, fungi, green plants or their enzymes to return the natural environment altered by contaminants to its original condition. To completely eliminate toxic contaminants occurring in sludges, and ground water contaminated with petroleum hydrocarbons, solvents, pesticides, wood preservatives, non-halogenated SVOCs, and BTEX and other organic chemicals, especially effective for remediating low level residual contamination in conjunction with source removal. Compared with other technologies, such as thermal desorption and incineration (which require excavation and heating), thermally enhanced recovery (which requires heating), chemical treatment (which may require relatively expensive chemical reagents), and in situ soil flushing (which may require further management of the flushing water), bioremediation may enjoy a cost advantage.
ENZYME CHARACTERIZATION OF ENDOPHYTIC ACTINOBACTERIA ISOLATED FROM TOMATO PLANTS
Endophytic actinobacteria produce active metabolites, protecting plant tissues against stress. They compounds are widely used in human and veterinary pharmaceutics and agriculture, and of several enzymes with biotechnological potential. The present study characterizes the enzymatic production of endophytic actinobacteria colonizing tomato plants. Twenty-three actinobacteria isolates were tested for the detection of amylase, pectinase, cellulose, lipase, esterase, caseinase, gelatinase and catalase, at three temperatures (25˚C, 28˚C and 30˚C) for 7 days. Substrate hydrolysis and enzymatic index (EI) were determined. The results showed that mean EI of all actinobacteria isolates was between 0.8 and 7.1. Although 30˚C was the temperature at which the highest number of isolates presented enzymatic activity, it was at 25˚C that amylase, pectinase, lipase and esterase activity reached the highest mean EI. Catalase was produced by all actinobacteria, while lipase, esterase and pectinase activity was observed for at least 20 isolates, regardless the incubation temperature. However, the highest number of isolates able to hydrolyze gelatin and cellulose (8) was observed when growth was carried out at 30˚C. The highest EI means were observed for the hydrolysis of lipases, while the lowest values were seen for the hydrolysis of cellulose.
PERVAPORATION DEHYDRATION OF ISOPROPANOL USING BLEND MEMBRANES OF SODIUM ALGINATE (SA) AND HYDROXY PROPYL CELLULOSE (HPC)
Sodium alginate (SA) and Hydroxy propyl cellulose (HPC) blend membranes(SA/HPC) were prepared by solution casting method, followed by crosslinking with gluteraldehyde (GA), were tested for the pervaporation (PV) dehydration of isopropanol. The blend membranes were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (X-RD) to assess intermolecular interactions and crystallinity. Thermo gravimetric analysis (TGA) confirms that the stability increased with increase of SA content in SA / HPC blend membranes. The morphology of membranes was characterized by SEM studies, to confirm the chemical interaction and compatibility of these blend membranes. Sorption studies were carried out to evaluate the extent of interaction and degree of swelling of the membranes, in pure liquids as well as in mixtures of water and isopropanol. Pervaporation dehydration using crosslinked SA-HPC blend membranes were evaluated by the varying experimental parameters i.e., feed composition and membrane thickness. It was found that blend membrane containing 20 wt% HPC (SA-HPC-20) gave a high selectivity of 1314 and that the flux is of 0.1884 Kg /m2 h for 10 wt % water containing feed mixture. Comparatively, a low selectivity of 607 was observed for pristine cross linked SA membrane with the same feed mixture. Flux of the pristine SA membrane increased from 0.092 to 0.137 Kg / m2h. For SA-HPC-20 membranes, flux increased from 0.1884 to 0.2879 Kg / m2h over the studied feed water compositions of 10-17.5 wt%. From the above results, it is concluded that the present blend membranes are a promising candidates for Pervaporation dehydration of isopropanol.
THERMAL AND OPTICAL PROPERTIES OF SODIUM-PHOSPHO - ZINC - NEODYMIUM OXIDE GLASS SYSTEM
Neodymium doped sodium phospho-zinc oxide glasses of the composition (80-x) NaPO3–20 ZnO – x Nd2O3 (where x = 0, 0.1, 0.3, 0.5, 0.7 mol %) have been synthesized by energy efficient microwave heating technique. In order to understand the role of neodymium in these glasses, the density, glass transition, refractive index, optical absorption and photoluminescence properties were investigated. The density and refractive index were found to increase with increasing neodymium concentration which is attributed to the formation of non-bridging oxygens (NBOs) in the glass matrices. The optical absorption spectra were measured in the wavelength range 300-1000 nm and the optical band gaps were determined. It was found that the optical band gap decreases with an increase in neodymium concentrationThe photoluminescence measurements showed luminescent peaks around 880 and 1060 nm, which are due to the radiative transitions 4F3/2 4I9/2 and 4F3/24 I11/2 of Nd3+ ions.
IN-VITRO ANTIBACTERIAL ACTIVITY OF COMMONLY USED TOOTHPASTES IN NIGERIA AGAINST DENTAL PATHOGENS
The in-vitro antibacterial activity of different brands of toothpaste on dental pathogens was investigated. A total of four different brands of toothpastes designated A, B, C and D were tested for their antibacterial effect on five dental pathogens namely, Streptococcus mutans, Staphylococcus epidermidis, Lactobacillus acidophilus, Klebsiella pneumoniae and Enterobacter species using agar well diffusion method at different concentrations. The result showed that all the toothpastes were effective against the test organisms. The diameter of zones of inhibition of brand A ranged from 18.0mm against L. acidophilus and K. pneumonia at 2:5 concentrations to 24.0mm against S. mutans at 4:5 concentrations, brand B ranged from 18.0mm (L. acidophillus) to 23.0mm (S. mutans), brand C ranged from 18.0mm (K. pneumonia) to 22.0mm (S. mutans) at 2:5 and 4:5 concentrations respectively while brand D zones of inhibition ranged from 18.0mm (K. pneumonia) to 23.0mm (S. mutans) at 2:5 and 4:5 concentrations respectively. On the average, brand D has the highest antibacterial effect against the test organisms (20.70mm) followed by brand C (20.60mm), then brand B (20.50mm) while brand A showed the least activity against the test organisms (20.30mm). The variations in the antibacterial activity of the various toothpastes compared favourably with the broad spectrum antibiotics, ampicillin, tetracycline and chloramphenicol. The effectiveness of these toothpastes is directly related to the antibacterial components in their formulations. Therefore, these brands of toothpastes and others with the same formulations can be used to control dental infections associated with the test organisms.
IMPACT OF REGIONAL VARIATION ON β-SITOSTEROL CONTENT IN VITEX NEGUNDO LINN. FRUITS: EVALUATION USING HPTLC
Vitex negundo L. (Verbenaceae) fruits are reported to possess a wide range of therapeutic properties. The present work is an attempt to evaluate the impact of regional variation on the content of β-sitosterol in V. negundo fruits using validated HPTLC method. Chromatographic separation was achieved on TLC plate pre-coated with silica gel 60 F254 using toluene: ethyl acetate: methanol: glacial acetic acid (8:1:0.5:0.3, v/v/v/v) as a mobile phase. Detection of β-sitosterol was carried out by derivatizing the plate with 10% methanolic sulphuric acid reagent followed by densitometric scanning using CAMAG TLC scanner 4 at 366 nm. The method was validated as per ICH guidelines. Statistical analysis of the data reveals that the content of marker in the samples from different geographical regions varied significantly
DEVELOPMENT OF HPTLC DENSITOMETRIC METHOD FOR ESTIMATION OF QUERCETIN IN BOMBAX CEIBA L. LEAVES
Bombax ceiba L. is a medicinally valuable herb in the ayurvedic and traditional systems of medicine. Various activities have been reported in almost all parts of Bombax ceiba, some of these include hypertensive, antioxidant, hypoglycemic, hepatoprotective, and antipyretic. Quercetin, one of the most important flavonoids is active against various cardio vascular diseases, cancer, tuberculosis, neurological diseases, cataract etc. In the present study High Performance Thin Layer Chromatography method has been developed for detection and quantification of quercetin in Bombax ceiba leaves. Increasing serial dilutions of reference standard quercetin (200 to 1000 μg/ml) were scanned at 366 nm to detect and quantify the concentrations of quercetin in the test sample. The estimated value obtained from the same was 5.38% quercetin in powdered leaf sample. The method provided a rapid and easy approach for detection and the quantization of the bio-marker quercetin.
MIXED LIGAND COMPLEXES OF BIVALENT METAL IONS WITH 2-HYDROXY METHYL PYRIDINE IN PRESENCE OF KOJIC ACID, MALTOL, ACETYL ACETONE AND TRIFLUORO ACETYL ACETONE - pH METRY
Stability constants associated with mixed ligand complexes of bivalent metal ions with 2-hydroxy methyl pyridine in presence of other O-O donors (viz., maltol, kojic acid, acetylacetone and trifluoroacetylacetone) was evaluated potentiometrically at T=30oC and I=0.1 M KNO3 in aqueous medium. Stability trend is discussed in terms of nature of donor atoms and substituent groups present on ligands. Distributions of various species as a function of pH are also drawn using BEST Computer program.
EFFECT OF NaCl ON SEED GERMINATION IN FIVE LEGUME CROPS.
The seeds of Dolichos bilflorus Roxb., Lens esculenta Moench., Phaseolus aconitifolius Jacq., Phaseolus aureus Roxb., and Trigonella foenum graecum Linn. were germinated under saline conditions at 2.5 to 300 mM levels of NaCl. The germination was studied / reported after every 24 h for five days. The emergence of radicle was considered as the criterion for seed germination.
It was observed that the germination remained unaffected in Moth bean (P. aconitifolius) and Mung (P. aureus) at all levels of salinity. On the other hand there was stimulation in germination in Horse gram (D. biflorus), Lentil (L. esculenta) and Fenugreek (T. foenum graecum) at lower salt regimes ( up to 50 mM NaCl). However, it was inhibited due to higher levels of salt concentration in the medium. From the results it appears that fenugreek is salt sensitive while Phaseolus species are tolerant to saline conditions during germination. The horse gram and lentil seem to be moderately salt tolerant.