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Int. J. Mol. Sci., Volume 6, Issue 3 (March-May 2005), Pages 177-202

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Research

Open AccessArticle Jubilite: A 4-,8-connected Cubic Structural Pattern in Space Group Pm3
Int. J. Mol. Sci. 2005, 6(3), 177-187; doi:10.3390/i6030177
Received: 22 October 2004 / Accepted: 19 May 2005 / Published: 23 May 2005
Cited by 6 | PDF Full-text (375 KB) | HTML Full-text | XML Full-text
Abstract
In the course of investigating structural modifications of the 3-,4-connected net known as the Pt3O4 structure-type (waserite), a novel 4-,8-connected structure-type was discovered. This lattice is generated by replacing the 3-connected trigonal planar vertices of the Pt3O4
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In the course of investigating structural modifications of the 3-,4-connected net known as the Pt3O4 structure-type (waserite), a novel 4-,8-connected structure-type was discovered. This lattice is generated by replacing the 3-connected trigonal planar vertices of the Pt3O4 structure-type with 4-connected tetrahedral vertices, to achieve a structure which possesses a generic empirical formula of JK6L8. In such a topological modification, the four 3-fold axes of the parent cubic, Pm3n, Pt3O4 structure-type are retained. Thus the 4-connected tetrahedral vertices are oriented so as to preserve cubic symmetry in the resulting Pm3, JK6L8 (jubilite) lattice. The unit cell contains a single 8-connected cubecentered vertex, six 4-connected distorted square planar vertices and eight 4-connected distorted tetrahedral vertices. It is a Wellsean structure with a Wells point symbol given by (4166484)(4282)6(4383)8 and a Schläfli symbol of (53/4, 4.2667). This latter index reveals a decrease in the lattice’s polygonality and concomitant increase in the connectivity through the transformation from waserite to jubilite. The topology of the parent waserite lattice (Pt3O4) corresponds to that of the Catalan structures with the Wells point symbol (84)3(83)4, which has the Schläfli symbol (8, 3.4285). Finally, it can be seen that a sequence of structure-types starting with waserite (Pt3O4) and moving to jubilite (JK6L8) and finally to fluorite (CaF2) represents a continuous crystallographic structural transformation in which the symmetry and topology undergo concomitant changes from one structure-type (waserite) to the other structure-types. The topology of the fluorite lattice, represented by the Wells point symbol (424)(46)2, and the Schläfli symbol (4, 51/3), indicates a discontinuous topological transformation from the intermediate jubilite lattice; like the discontinuous topological transformation from Pt3O4 to JK6L8; in which the polygonality is again reduced, in this step from 53/4 to 4, and the connectivity is concomitantly increased, from 4.2667 to 51/3, during the continuous structural transformation. The l index, a topological measure of the form of a structure-type in terms of the ratio of the weighted average polygonality to the weighted average connectivity in the unit cell, decreases in the sequence from Pt3O4 (2.3333) to jubilite (1.3476) to fluorite (0.7500). This indicates the discontinuous, though monotonic, appearance of more closed networks upon increasing the connectivity and concomitantly decreasing the polygonality in the structural sequence. Interestingly, the ratios of the form indexes of the adjacent members in this series: lwaserite/ljubilite and ljubilite/lfluorite, are approximately equal to each other. Full article
Open AccessArticle Octopamine Levels in Blattella Germanica L. Tissues by Capillary Gas Chromatography with Electron Capture Detection
Int. J. Mol. Sci. 2005, 6(3), 188-197; doi:10.3390/i6030188
Received: 27 October 2004 / Accepted: 18 May 2005 / Published: 24 May 2005
Cited by 1 | PDF Full-text (105 KB) | HTML Full-text | XML Full-text
Abstract
Distribution and levels of octopamine (OA), one of the biogenic amines in the invertebrate nervous system, may have significant effects on insect physiological processes including growth, feeding and reproduction. In this paper capillary gas chromatography with electron capture detection (GC-ECD) and mass selective
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Distribution and levels of octopamine (OA), one of the biogenic amines in the invertebrate nervous system, may have significant effects on insect physiological processes including growth, feeding and reproduction. In this paper capillary gas chromatography with electron capture detection (GC-ECD) and mass selective detection (GC-MS) were used to determine the content of OA in Blattella germanica L. central nervous system (CNS), and that of OA in cockroach stressed by kinds of insecticides, known octopaminergic agonists and some essential oils. A derivatization method for organic extracts via reaction with pentafluoropropionic anhydride (PFPA) was developed. The resulting OA derivatives were confirmed by GC-MS to be tris-pentafluoropropionyl-OA. The method was used to quantify the amount of OA in insect issues by capillary GC-ECD through an extraction-derivatization-liquid/liquid partition procedure. Average OA content in normal cockroaches was determined to be 68.49 ± 7.31 ng/g tissue (N=5 determinations). It was shown that insecticides including chlordimeform, methomyl, permethrin, chlorfluazuron, malathion, trichlorfon and some oxazolidine agonists, essential oils including eugenol, cinnamic alcohol, phenyl ethyl alcohol could led to significant increase of OA levels in the cockroach CNS comparing with which in insect treated by 1-butanone. Malathion, trichlorfon, chlorfluazuron and cinnamic alcohol were shown to be able to cause a 20- fold increase in OA levels. Full article
Open AccessArticle Study on the XPS-ESCA of Aluminum Phosphide Products
Int. J. Mol. Sci. 2005, 6(3), 198-202; doi:10.3390/i6030198
Received: 1 August 2004 / Accepted: 18 May 2005 / Published: 25 May 2005
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Abstract
XPS-ESCA analysis showed small signal for phosphorus in fresh specimens of aluminum phosphide (AlP). After removal of a layer of about 0.5 – 1.0 μm by argon ion sputtering, it was observed that signal intensities from oxygen and aluminum increased. The oxygen signal
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XPS-ESCA analysis showed small signal for phosphorus in fresh specimens of aluminum phosphide (AlP). After removal of a layer of about 0.5 – 1.0 μm by argon ion sputtering, it was observed that signal intensities from oxygen and aluminum increased. The oxygen signal decreased as a function of sputtering time, synchronously with the increase of the phosphorous signal from the AlP nucleus. The aluminum signal, which was considered to be mainly due to AlP and Al(OH)3, remained constant. Other impurity elements including N, Mg, etc., were identified in the technical 85% AlP and AlP tablet formulated products. Full article

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