Synthesis of melanervin from melaleuca quinquenervia,the first naturally occurring compound with a triphenylmethane structure

Melanervin from Melaleuca quinquenervia, the first naturally occurring compound with a triphenylmethane structure, has been synthesized and its structure thereby confirmed.     

Heavy-metal remediation by a fungus as a means of production of lead and cadmium carbonate crystals

We show here that reaction of the fungus, Fusarium oxysporum, with the aqueous heavy-metal ions Pb2+ and Cd2+ results in the one-step formation of the corresponding metal carbonates. The metal carbonates are formed by reaction of the heavy-metal ions with CO2 produced by the fungus during metabolism and thus provide a completely biological method for production of crystals of metal carbonates. The PbCO3 and CdCO3 crystals thus produced have interesting morphologies that are shown to arise because of interaction of the growing crystals with specific proteins secreted by the fungus during reaction. An additional advantage of this approach is that the reaction leads to detoxification of the aqueous solution and could have immense potential for bioremediation of heavy metals. Under conditions of this study, the metal ions are not toxic to the fungus, which readily grows after exposure to the metal ions.     

Water Pollution Threat to the Environment by a Urea Plant

Disposal of untreated industrial effluents is drastically deteriorating the quality of underground water. Research work has been conducted to analyze the effect of disposal of urea plant effluent on the quality of ground water of the District Mianwali Daudkhail, Pakistan. For this purpose the effluent and ground water samples were analyzed for pH, TDS, TSS, Cl, F, COD, BOD, Fe, Zn, Pb, Cu, Cr, Cd, Mn, and As. Results obtained were compared with WHO and NEQS standards for drinking and effluent emission limits, respectively. Moreover, effluent samples were also evaluated for irrigation purposes and results compared with criteria recommended for irrigation water. Results showed though the effluents were according to the standards given by National Environmental Quality Standards (NEQS) for liquid emission and fit for irrigation purposes, the quality of underground water was below standard due to having a higher quantity of total dissolved solids than permissible.     

A study of simultaneous photolysis and photoaddition reactions of riboflavin in aqueous solution

The photodegradation reactions of riboflavin (RF) in the presence of 0.05-2.00 M phosphate (pH 7.0) have been studied using a specific multicomponent spectrophotometric method. The reactions involve simultaneous photolysis (intramolecular photoreduction) and photoaddition (intramolecular photoaddition) leading to lumichrome (LC) and cyclodehydroriboflavin (CDRF), respectively, as major products. The contribution of each reaction in the overall photodegradation depends upon the phosphate concentration, i.e., higher the phosphate concentration higher the extent of photoaddition. The apparent first-order rate constants for the photodegradation of RF and for the formation of LC and CDRF at 0.25-2.00 M phosphate concentration range from 0.65 to 3.03 x 10(-2), and from 0.41 to 0.99 x 10(-2) and 0.12 to 1.63 x 10(-2) min(-1), respectively. The second-order rate constants for the phosphate catalysed photodegradation of RF and for the formation of LC and CDRF are 2.12 x 10(-4) and 0.61 x 10(-4) and 1.41 x 10(-4) M(-1)s (-1), respectively. Since the formation of CDRF by photoaddition is catalysed by HPO(4)(2-) ions, it is suggested that H(2)PO(4)(-) ions may be involved in the formation of LC by photolysis. Thus, both H(2)PO(4)(-) and HPO(4)(2-) ions may catalyse the two major reaction pathways of riboflavin photodegradation, respectively.     

A generalized technique for the encapsulation of nano‐sized NiO particles by styrene‐2‐hydroxyethyl methacrylate copolymer

Encapsulation of nickel oxide (NiO) particles is of great interest to the researchers as such modification produces remarkable improvement in properties and versatility in application potential. In this investigation, nanosized NiO particles were first prepared by calcination of nickel hydroxide precursor obtained using a simple liquid‐phase process. The produced NiO particles were stabilized with oleic acid and then treated with tetraethylorthosilicate to produce NiO/SiO₂ composite seed particles. Finally tri‐layered inorganic/organic composite particles were prepared by seeded copolymerization of styrene and 2‐hydroxyethyl methacrylate (HEMA) in the presence of NiO/SiO₂ composite seed particles. The produced composite particles named as NiO/SiO₂/P(S‐HEMA) were colloidally stable, and the obtained particles were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy and thermogravimetric analyses. Copyright © 2015 John Wiley & Sons, Ltd.     

Optimization and Validation of RP-LC/UV–VIS Detection Method for Simultaneous Determination of Fat-Soluble Anti-Oxidant Vitamins, all-trans-Retinol and α-Tocopherol in Human Serum: Effect of Experimental Parameters

A versatile isocratic reversed-phase liquid chromatographic/ultraviolet–visible detection method for simultaneous determination of all-trans-retinol and α-tocopherol in human serum was developed and validated after optimization of various chromatographic conditions and other experimental parameters. Analytes were separated on a Kromasil 100 RP₁₈ (150 × 4.6 mm, 5 μm) analytical column protected by a Perkin Elmer RP₁₈ (30 × 4.6 mm, 10 μm) guard cartridge. The mobile phase, methanol–water (96:04 v/v) was pumped at a flow rate of 2.2 mL min^?1 and the column eluents were monitored at the wavelength of 292 nm using retinyl acetate (1.0 μg mL^?1) as the internal standard for both analytes. Sample preparation was based on protein precipitation and stabilization with 2,6-bis(1,1-dimethylethyl)-4-methylphenol/ethanol and a two step extraction process using n-hexane followed by dichloromethane as extraction solvents. Sample size was kept 20 μL and separation of analytes was achieved in less than 7 min. The present method demonstrated acceptable values for specificity/selectivity, linearity within the expected concentration range, recovery, precision, sensitivity, stability of solutions, robustness, and system suitability specifications and tests. The method was used for monitoring all-trans-retinol and α-tocopherol concentrations in human serum samples and could also be applied to other sample matrices such as brain slices and cosmetic products if attention is paid to the extraction procedure.     

Reinforcement of natural rubber/high density polyethylene blends with electron beam irradiated liquid natural rubber-coated rice husk

Coating of rice husk (RH) surface with liquid natural rubber (LNR) and exposure to electron beam irradiation in air were studied. FTIR analysis on the LNR-coated RH (RHR) exposed to electron beam (EB) showed a decrease in the double bonds and an increase in hydroxyl and hydrogen bonded carbonyl groups arising from the chemical interaction between the active groups on RH surface with LNR. The scanning electron micrograph showed that the LNR formed a coating on the RH particles which transformed to a fine and clear fibrous layer at 20 kGy irradiation. The LNR film appeared as patches at 50 kGy irradiation due to degradation of rubber. Composites of natural rubber (NR)/high density polyethylene (HDPE)/RHR showed an optimum at 20–30 kGy dosage with the maximum stress, tensile modulus and impact strength of 6.5, 79 and 13.2 kJ/m², respectively. The interfacial interaction between the modified RH and TPNR matrix had improved on exposure of RHR to e-beam at 20–30 kGy dosage.     

Development and validation of a HPLC method for the determination of buprenorphine hydrochloride, naloxone hydrochloride and noroxymorphone in a tablet formulation

A simple isocratic reversed-phase high-performance liquid chromatographic method (RP-HPLC) was developed for the simultaneous determination of buprenorphine hydrochloride, naloxone hydrochloride dihydrate and its major impurity, noroxymorphone, in pharmaceutical tablets. The chromatographic separation was achieved with 10 mmol L⁻¹ potassium phosphate buffer adjusted to pH 6.0 with orthophosphoric acid and acetonitrile (17:83, v/v) as mobile phase, a C-18 column, Perfectsil Target ODS3 (150 mm × 4.6 mm i.d., 5 μm) kept at 35 °C and UV detection at 210 nm. The compounds were eluted isocratically at a flow rate of 1.0 mL min⁻¹. The average retention times for naloxone, noroxymorphone and buprenorphine were 2.4, 3.8 and 8.1 min, respectively. The method was validated according to the ICH guidelines. The validation characteristics included accuracy, precision, linearity, range, specificity, limit of quantitation and robustness. The calibration curves were linear (r > 0.996) over the concentration range 0.22-220 μg mL⁻¹ for buprenorphine hydrochloride and 0.1-100 μg mL⁻¹ for naloxone hydrochloride dihydrate and noroxymorphone. The recoveries for all three compounds were above 96%. No spectral or chromatographic interferences from the tablet excipients were found. This method is rapid and simple, does not require any sample preparation and is suitable for routine quality control analyses.     

An unexpected, novel, three-component reaction between isoquinoline, an isocyanide and strong CH-acids in water

An unexpected three-component condensation reaction between an isocyanide, isoquinoline and a strong CH-acid efficiently provides 1,2-dihydroisoquinoline derivatives in a one-pot reaction in water at 70 °C without using any catalyst.     

Negative ion FAB mass spectroscopy of some ribose alkylated 5'-UMP derivatives

Characteristic fragment ions obtained in Fast atom bombardment (FAB) mass spectroscopy of ribose alkylated Uridine 5'-monophosphate (5'-UMP) derivatives in negative ion mode are described. All the compounds examined exhibited either [M]- or quasimolecular ion [M - H]- the fragmentations can be used to characterize these nucleotides.