Selection of Maceration Solvent for Natural Pigment Extraction from Red Fruit (Pandanus conoideus Lam)

Red fruit (Pandanus conoideus Lam) is rich with red-orange natural pigments, such as β-carotene. In this work, the solvent selection was investigated to extract the β-carotene from the red fruit via a simple maceration technique. Three types of solvents were used in the maceration, which were distilled water, ethanol, and acetone. The obtained extracts were characterized using spectrophotometer ultraviolet-visible (UV-visible), Fourier transform infrared (FTIR) and spectrofluorometer. The different solvents gave different spectroscopic information, suggesting that the solvent selection influenced the type of the extracted compounds. Among the examined solvents, acetone was found to be the most effective one to extract the β-carotene. The presence of the β-carotene pigment in acetone extract was confirmed by the appearance of the absorption peak at 476 nm on its UV-visible spectrum, while from its FTIR spectrum, the C-H sp3 functional group of β-carotene was found at 2924 and 2854 cm-1. In addition, the emission peak of β-carotene was found at 394 and 561 nm. This study confirmed that acetone performed as a better maceration solvent for β-carotene as compared to the distilled water and ethanol, which would be strongly related to the non-polar property of the acetone.

Effect on electrospun fibres by synthesis of high branching polylactic acid

Polylactic electrospun porous fibres have been widely used in tissue engineering scaffolds. However, the application of linear polylactic is limited due to its poor hydrophilicity, which leads to phase separation and has been seldom used in porous fibre preparation. Instead, branching polylactic acts as a new effective method to prepare porous fibres because it can increase polylactic polar property and make it easy to be formulated in the following application. In the current study, we prepared an ultra-high molecular weight of high branching polylactic with glycerol as the initiator by controlling the ring-opening polymerization time, adding amount of catalyst and glycerol. The structure, molecular weight and thermal properties of copolymers were tested subsequently. The result showed that the surface of the high branching polylactic films is smooth, hydrophilic and porous. This branching polylactic formed electrospun porous fibres and possessed a strong adsorption of silver ion. Our study provided a simple and efficient way to synthesize branching polylactic polymer and prepare electrospun porous fibres, which may provide potential applications in the field of biomaterials for tissue engineering or antibacterial dressing compared with the application of linear polylactic and 3-arm polylactic materials.

Polyethylene plastic production process

<p>Polyethylene has become the most important polyolefin plastic with excellent mechanical properties, processing properties and chemical stability. It is used in the production of film, packaging and pipe. However, the non-polar property and low rigidity limit its application in certain fields. The new progress of chemical and physical modification upon polyethylene are reviewed. The former includes graft modification, chlorination, copolymerization modification, crosslinking modification, chlorosulfonation modification and plasma modification. There are different methods of polyethylene production which include high-, medium- and low-pressure polyethylene. All three methods had their own benefits and shortcomings which coexist in the industry. <br /><br /></p>

Geometrical Properties of Three Symmetric Matrices

In the early editions of the Geometry of Three Dimensions Salmon had stated that the equations of any three quadric surfaces could be simultaneously reduced to the sums of five squares. Such a reduction is not possible in general, but can be performed if and only if a certain combinant Λ, of the net of quadrics, vanishes. Algebraically the theory of such a net of quadrics is equivalent, as Hesse(2) showed, to that of a plane quartic curve: and the condition for the equation a quartic to be expressible to the sum of five fourth powers is equivalent to the condition Λ = 0(1). While Clebsch(3) was the first to establish this condition, Lüroth(4) gave it more explicit form by studying the quartic curvewhich satisfies the condition. Frahm(5) seems to have been the first to prove the impossibility of the above reduction of three general quadric surfaces, by remarking that the plane quartic curve obtained in Hesse's way from the locus of the vertices of cones of the net of quadrics would be a Lüroth quartic. Frahm further remarked that the three quadrics, so conditioned, could be regarded as the polar quadrics belonging to a cubic surface in ∞2 ways; but that for three general quadrics no such cubic surface exists. An explicit algebraical account of these properties was given by E. Toeplitz(6), who incidentally noticed that certain linear complexes associated with three general quadrics became special linear complexes when Λ = 0. This polar property of three quadrics in [3] was generalized to n dimensions by Anderson (7).