New lipids from the soft corals of the Andaman Islands

Sphingolipids and glycolipids including previously unknown (2S,3S,4R)-1,3,4-trihydroxy-2-(2-(R)-hydroxyoctadecanoylamino)octadec-8E-ene, (2S,3R)-1,3-dihydroxy-2-octadecanoylamino-4E,8E-hexadecadiene, and (2-hydroxy-3-hexadecyloxypropyl)--L-fucopyranoside were isolated from soft corals collected on the shelf near the Andaman Islands (Indian Ocean). The structures of all compounds were established by spectroscopic methods and chemical analyses. The lipids possessed antibacterial activity against Bacillus subtilis, Bacillus pumilus, Escherichia coli, and Pseudomonas aeruginosa and antifungal activity against Aspergillus niger, Rhizopus oryzae, and Candida albicans.     

Ca(Ⅱ)、Mg(Ⅱ)和Zn(Ⅱ)与丙二醇-水混合体系中L-多巴的二元配合物的生成平衡

在303 K恒温条件下,以NaCl为电解质保持离子强度为0.16 mol·L^-1,用pH滴定法研究了M(Ⅱ)-Dopa(多巴)二元配合物在0～60%(V/V)的丙二醇(PG)-水体系中的生成平衡。在PG-水体系中,Ca(Ⅱ)和Mg(Ⅱ)的典型配合物为MLH,ML₂,ML₂H和ML₂H₂,而Zn(Ⅱ)的典型配合物为ML,MLH,ML₂,ML₂H和ML₂H₂。根据静电和非静电力解释了稳定常数随介质的介电常数而变化的倾向。还讨论了在不同组成的丙二醇(PG)-水体系中配合物物种随pH值变化的情况。     

Ca(Ⅱ)、Mg(Ⅱ)和 Zn(Ⅱ)与丙二醇-水混合体系中L-多巴的二元配合物的生成平衡

在303 K恒温条件下,以NaCl为电解质保持离子强度为0.16 mol.L-1,用pH滴定法研究了M(Ⅱ)-Dopa(多巴)二元配合物在0~60%(V/V)的丙二醇(PG)-水体系中的生成平衡。在PG-水体系中,Ca(Ⅱ)和Mg(Ⅱ)的典型配合物为MLH,ML2,ML2H和ML2H2,而Zn髤的典型配合物为ML,MLH,ML2,ML2H和ML2H2。根据静电和非静电力解释了稳定常数随介质的介电常数而变化的倾向。还讨论了在不同组成的丙二醇(PG)-水体系中配合物物种随pH值变化的情况。     

Agallochins J-L,new isopimarane diterpenoids from Excoecaria agallocha L

The ethyl acetate extract of Excoecaria agallocha L. furnished three more new isopimarane diterpenoids, 11alpha,14alpha-dihydroxy-7,15-isopimaradien-3-one, agallochin J (1), 3alpha, 1alpha,14alpha-trihydroxyisopimara-7,15-diene, agallochin K (2) and 6alpha,14alpha,17-trihydroxy-7,15-isopimaradien-3-one, agallochin L.     

Adsorption of cesium on a composite inorganic exchanger zirconium phosphate - ammonium molybdophosphate

The applicability of zirconium phosphate-ammonium molybdophosphate (ZrP-AMP) for the efficient removal of cesium from aqueous acidic solutions by adsorption has been investigated. The adsorption data analysis was carried out using the Freundlich, Dubinin-Raduskevich (D-R) and Langmuir isotherms for the uptake of Cs in the initial concentration range of 3.75^.10^-5-7.52^.10^-3 mol^.dm^-3 on the ZrP-AMP exchanger from nitric acid medium. The mean free energy (E) values for the adsorption of Cs were obtained from the D-R isotherm. Equilibrium adsorption values at different temperatures have been utilized to evaluate the change in enthalpy, entropy and free energy (ΔH°, ΔS°, ΔG°). The adsorption of cesium on the ZrP-AMP exchanger was found to be endothermic. This revised version was published online in August 2006 with corrections to the Cover Date.     

Measurement,correlation and estimation of binary vapor—liquid equilibria for alcohol—chlorobenzene systems

Experimental VLE of chlorobenzene—1-pentanol binary mixtures are determined at 101.08 kPa. Also, the activity coefficients at infinite dilution (γ^∞) for some alcohol—chlorobenzene systems are determined from ebulliometric measurements. The Wilson equation is tested for 10 binary alcohol—chlorobenzene systems. The results show that this model represents the data well. There is good comparison between experimental γ^∞,s and γ^∞,s computed from Wilson parameters. Further, the VLE data for the above-mentioned mixtures are estimated by the UNIFAC method.     

Transformations of lignans. Part 10: Acid-catalysed rearrangements of arboreol and wodeshiol and conversion of gmelanone oxime into a dihydropyranone derivative

The synthesis of gmelanone 2 by a pinacol-type rearrangement of arboreol 1 supports its biogenesis and confirms its relative and absolute configuration. The further transformation of gmelanone oxime 12 into the dihydropyranone oxime 13 supports the intermediacy of gmelanone like intermediates in the rearrangements of furofuran lignans to pyran derivatives. In contrast, acid-catalysed rearrangement of wodeshiol 7 affords the dihydropyranone 8.     

CoⅡ，NiⅡ和CuⅡ与L-组氨酸和L-谷氨酸在1，4二氧六环-水混合物中混合配体配合物的生成平衡

在303.0 K维持离子强度为0.16 mol.L-1,体积比为0.0～60.0%的1,4二氧六环-水混合体系中用pH滴定法研究了CoⅡ,NiⅡ和CuⅢ离子与L-组氨酸和L-谷氨酸混合配体配合物的生成平衡。对不同的金属(M)与L-组氨酸(L)、L-谷氨酸(X)比(cM∶cL∶cX=1∶2.5∶2.5,1∶2.5∶5.0,1∶5.0∶2.5)的体系进行了碱量滴定。计算了三元配合物的稳定常数并用MINIQUAD75对各种模型进行了优化。根据统计数据和残差分析结果选取了最合适的化学模型。检测到的物种:对CoII而言为MLX2H2-和MLX23-,对NiⅡ和CuⅡ而言为MLXH,MLX2H2-和MLX23-。就有关浓度和稳定性对三元物种与二元物种进行了比较。三元物种的额外稳定性可归因于电荷中和,鳌合效应,堆叠作用和氢键等。     

Co(Ⅱ)，Ni(Ⅱ)和Cu(Ⅱ)与L-多巴和1，10-菲咯啉在低介电介质中三元配合物体系的化学物种

对M髤[M=Co,Ni and Cu]与L-多巴(L)和1,10-菲咯啉(X)在的1,4-二氧杂环己烷(DOX)-水混合物【0~60%(V/V)】三元配合物体系在(303.0±0.1)K和离子强度为0.16 mol.L-1情况下进行pH滴定。结果表明:对Co髤和Cu髤而言,三元物种为MLX2H,MLXH,ML2X和MLX,但对Ni髤而言,三元物种为MLX2H,MLXH和MLX。三元物种的稳定性和浓度随介质的介电常数的变化趋势根据静电和非静电力作出解释。同时还给出了物种在不同pH值的DOX-水混合物中的分布图。根据滴定曲线推论了各种二元和三元配合物的生成。用两种方法解释了三元配合物比对应的二元配合物稳定的原因。     

Structural and magnetic properties of Mg substituted NiCuZn Nano Ferrites

The present paper examines the effect of magnesium substitution on structural and magnetic properties of NiCuZn nano ferrites synthesised by sol-gel method. The prepared samples were characterised by using X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM) and Vibration sample magnetometer (VSM) techniques. The phase identification, unit cell parameter and crystallite size was determined using XRD analysis. The lattice constant reduced with increasing Mg content. Room temperature saturation magnetisation and coercivity showed reverse trend with increasing Mg content. Curie temperature (T_c) obtained from the thermo magnetic curves increases with Mg concentration. The initial permeability (μ_i) decreased with increasing Mg content. This is due to reduced magnetisation, grain size and increased magneto-crystalline anisotropy constant. Simultaneously, there is an upward shift of domain wall relaxation frequency with increasing Mg content. Also the permeability is observed to be constant up to 30 MHz frequency range showing compositional stability and quality of the material. The prepared samples were suitable for applications in Multilayer Chip Inductors due to their invariable permeability up to 30 MHz frequency and high thermal stability along with low sintering temperature.