Studies on the sorption capacity for Pb(II) and Hg(II) of citralidene chitosan

Citralidene chitosan, prepared by condensation of citral and chitosan, was characterized by infrared spectroscopy, scanning electron microscopy and differential scanning calorimetry and evaluated for its Pb(II) and Hg(II) sorption capacity. The contact time for Pb(II) and Hg(II) sorption was found to be 5 and 4 h, respectively. The sorption data best fitted to pseudo second-order equation. The equilibrium sorption data were found to be best fitted to Langmuir model. The studies revealed that the citralidene chitosan has different binding sites and the sorption was spontaneous and exothermic. Citralidene chitosan was found to be an efficient and cheap sorbent for Pb(II) and Hg(II).     

Curcuma longa and Curcuma mangga leaves exhibit functional food property

Although leaves of Curcuma mangga and Curcuma longa are used in food preparations, the bioactive components in it are not known. In this study, antioxidant, antiinflammatory and anticancer activities of leave extracts and its isolates were investigated using established bioassay procedures in our laboratory. The leaf extracts of both plants gave similar bioassay and chromatographic profiles. The methanolic and water extracts of C. mangga (CMM and CMW) and C. longa (CLM and CLW), at 100 μg/mL, inhibited lipid peroxidation (LPO) by 78%, 63%, 81% and 43%, cyclooxygenase enzymes COX-1 by 55%, 33%, 43% and 24% and COX-2 by 65%, 55%, 77% and 69%, respectively. At same concentration, CMM, CMW, CLM and CLW showed growth inhibition of human tumour cell lines by 0-46%. Therefore, a bioassay-guided isolation of water and methanolic extracts of C. longa was carried out and afforded nine isolates. At 25 μg/mL, these compounds inhibited LPO by 11-87%, COX-1 and -2 enzymes by 0-35% and 0-82% and growth of human tumour cells by 0-36%, respectively.     

Labdane diterpenes in Curcuma mangga rhizomes inhibit lipid peroxidation,cyclooxygenase enzymes and human tumour cell proliferation

The rhizome of “Mango Ginger”, Curcuma mangga (Zingiberaceae), is a dietary ingredient in India and its popularity is similar to the rhizomes of Curcuma longa (Zingiberaceae), the “turmeric root”. In Indian folk medicine, the rhizomes of C. mangga have been used as medicine to treat a variety of diseases for centuries. However, it has not been investigated for its bioactive constituents. In our study, the aqueous, methanolic and ethyl acetate extracts of its rhizome showed antioxidant, anti-inflammatory and anti-tumour activities. Purification of these active extracts yielded bioactive labdane diterpenoids labda-8(17)-12-diene-15,16-dial (1), calcaratarin A (2), communic acid (3), copallic acid (4), zerumin B (5), 14,15,16-trinor-labdan-8,12-diol (6) and two decalins (7–8). The structures were elucidated by spectral analyses. All pure isolates inhibited lipid peroxidation (LPO) by 12–45% at 25 μg/ml. In cyclooxygenase enzymes (COX-1 and -2) inhibitory assays, compounds 1–4 showed selective COX-2 enzyme inhibition by 39–55% where as 5–8 showed selectivity to COX-1 between 45% and 53%. The tumour cell proliferation inhibition by these compounds was determined by using NCI-H460 (lung), HCT-116 (colon), AGS (gastric), SF-268 (CNS) and MCF-7 (breast) human tumour cell lines. All isolates tested at 25 μg/ml showed some degree of inhibition against tumour cell progression.     

Thermodynamic properties of PrRhO3 and phase diagrams of the system Pr–Rh–O

A solid-state electrochemical cell with yttria-stabilized zirconia (YSZ) as the electrolyte is used to measure accurately thermodynamic properties of PrRhO₃ in the range of temperature from 875 to 1325 K. The standard Gibbs energy of formation of PrRhO₃ with orthorhombically distorted perovskite structure from its binary oxides β-Rh₂O₃ and hexagonal Pr₂O₃ is given by, . Invoking the Newmann-Kopp rule, the standard enthalpy of formation from elements and standard entropy of PrRhO₃ at 298.15 K are evaluated: and . Phase relations in the system Pr–Rh–O at 1200 K are computed from thermodynamic data. Calorimetric data on enthalpy of formation of two intermetallic compounds are combined with the semi-empirical model of Miedema and phase diagram to estimate Gibbs energy of formation for the intermetallics and liquid alloys. An isothermal section of ternary phase diagram, an oxygen potential-composition diagram in 2-D and a 3-D chemical potential diagram for the system Pr–Rh–O at 1200 K are presented. In addition, temperature-composition diagrams at different oxygen pressures are developed. The diagrams provide a road map for design and optimization of processing routes for catalysts based on Rh.     

Magnolia virginiana Neolignan compounds as chemical barriers to swallowtail butterfly host use

The role of toxins and deterrents in preventingtroilus group species (Lepidoptera, Papilionidae) from feeding on magnoliaceous hosts was investigated using bioassay-directed isolation ofMagnolia virginiana allelochemicals. A fraction consisting of three neolignan compounds significantly reduced survival of first instarP. palamedes, atroilus group member. Two of these compounds, magnolol and a biphenyl ether, were tested individually and were both toxic toP. palamedes. The larval survival ofP. troilus, anothertroilus group species, was also significantly reduced by magnolol but not by the biphenyl ether. In contrast,P. glaucus, a polyphagousglaucus group species that feeds on magnoliaceous hosts, was not affected by either compound. The effect of these compounds against a. polyphagous nonpapilionid was examined using the fall webworm (Hyphantria cunea, Lepidoptera: Arctiidae). The biphenyl ether but not magnolol significantly lowered webworm first-instar survival, demonstrating that polyphagy does not preadapt lepidopterans to feeding on this neolignan. These results demonstrate that although phagostimulants play a role in the specialization of thetroilus group on the Lauraceae, the presence of toxins and/or deterrents in nonhosts is also important in determining food plant patterns in these species.     

Ferulate esters of higher fatty alcohols and allelopathy inKalanchöe daigremontiana

Ferulate esters of normal C₂₂–C₃₀ alcohols were found in the root extract ofKalanchöe daigremontiana and the freen-C₃₀ alcohol, triacontanol, was found on the leaves. Ferulic acid was isolated from the vermiculite in which plants were grown. Whole plant and tissue culture experiments were done to investigate the role of ferulic acid as an allelochemical and of triacontanol as a plant growth regulator inK. daigremontiana and other bioassay systems. No positive growth responses to triacontanol were observed, but inhibitation of growth response of plantlets by ferulic acid was seen.     

Microstructure and its correlation to magnetic properties in 2:17 type (Sm,Gd)-Co-Fe-Cu-Zr alloys

Studies on the evolution of microstructure and phase transformation at various stages of thermal processing have been carried out in 2:17 type (Sm,Gd)-Co-Fe-Cu-Zr alloys. Microstructural studies reveal that during the solution heat treatment stage, a lamellar structure is formed and its volume fraction is found to be more at 1463 K for alloys without Gd, while at 1473 K for alloys with Gd = 25 wt% of Sm. It appears that the formation of the lamellar structure is closely associated with the phase transformation from Th₂Ni₁₇ (TbCu₇ + Th₂Zn₁₇) structure during the solution heat treatment. Magnetic measurements in isothermally aged (1123 K) samples showed that the replacement of 25% of Sm by Gd reduces the energy product from 180 to 136 kJ/m³. The Gd substitution is also found to reduce the temperature coefficient of magnetisation from 350 to 225 ppm/°C in the temperature range of 30–100°C.     

Transformations in a Ti-24AI-15Nb alloy: Part I. Phase equilibria and microstructure

A variety of heat treatments have been employed to explore phase equilibria and the development of microstructure in a Ti-24Al-15Nb alloy. These include solution treatments both above and below the β-transus, followed by controlled cooling and aging at temperatures high enough to preclude ω-phase formation. The phase fieldsβ, β _o, α₂ + β_o, α₂ +β _o + O, andβ _o + O have been identified in the alloy, and schematic time-temperature-transformation (TTT) curves are proposed for continuous cooling transformations from theβ phase. The composition of the α₂ andβ _o phases in the α₂ +β _o region and of the α₂,β _o and O phases in the ternary phase field have been obtained by analytical electron microscopy.