This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes' of Volume 10 'Heats of Mixing and Solution' of Landolt-Börnstein - Group IV 'Physical Chemistry'.

It contains:

State: Two-component system, single-phase liquid or two-phase liquid-liquid (LL).

Components: 1. C₅H₁₂, Pentane [109-66-0]; 2. C₆H₆, Benzene [71-43-2].

Parameters: T/K, Temperature.

Variables: x₁/-, Mole fraction of component 1; H^E/J mol^-1, Molar excess enthalpy.

Method: Direct low-pressure calorimetric measurement of H^E at variable x₁ and constant T.

File Number: LB2948

A new lectin gene was isolated by using genomic walker technology and revealed to encode a mannose-binding lectin. Analysis of a 2233 bp segment revealed a gene including a 1169 bp 5′ flanking region, a 417 bp open reading frame (ORF) and a 649 bp 3′ flanking region. There are two putative TATA boxes and eight possible CAAT boxes lie in the 5′ flanking region. The ORF encodes a 15.1 kDa precursor, which contains a 24-amino acid signal peptide. One possible polyadenylation signal is found in the 3′-flanking region. No intron was detected within the region of genomic sequence corresponding to zaa (Zantedeschia aethiopica agglutinin) full-length cDNA, which is typical of other mannose-binding lectin gene that have been reported. The deduced amino acid sequence of the lectin gene coding region shares 49–54% homology with other known lectins. The cloning of this new lectin gene will allow us to further study its structure, expression and regulation mechanisms.

Many expression systems in research and industry use plasmids as vectors for the production of recombinant proteins or non-proteinous recombinant substances. Plasmids have an essential impact on productivity. Related factors are plasmid copy number, structural plasmid stability and segregational plasmid stability. Plasmid copy number determines the gene dosage accessible for expression and many plasmids lead generally to a high productivity. To analyze an expression system the quantification of plasmid copy number is very helpful. Therefore, different methods for the determination of plasmid copy number are described. Structural plasmid stability exists, when all generated plasmids have the correct base sequence. The analysis of structural instabilities is not trivial and some methods are reported. When all daughter cells get at least one plasmid during cell division, the culture is segregational stable. The development of plasmid free cells can lead to a significant loss in productivity. Different methods for lab scale and industrial scale help to avoid segregational instability. Since plasmids are used as pharmaceuticals, additional aspects of stability have to be taken into account. These include stability during downstream processing, stability after application and stability during storage and shipping.

This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes' of Volume 10 'Heats of Mixing and Solution' of Landolt-Börnstein - Group IV 'Physical Chemistry'.

It contains:

State: Two-component system, single-phase liquid or two-phase liquid-liquid (LL).

Components: 1. CH₄O, Methanol [67-56-1]; 2. C₆H₁₄O, Methyl 1,1-dimet hylpropyl ether [994-05-8].

Parameters: P/Pa, Pressure; T/K, Temperature.

Variables: x₁/-, Mole fraction of component 1; H^E/J mol^-1, Molar excess enthalpy.

Method: Direct calorimetric measurement of H^E at variable x₁ and constant P and T.

File Number: LB2862

Modern methods for the detection and neutralization of explosives are important components of the complex actions for prevention of terrorist acts. Creation of effective efforts for detection of explosive devices now is one of the actual tasks of strengthening the activity of antiterrorist divisions. During development and creations of these means give the basic attention to detection of the various explosives making of a basis of any explosive device. Special attention to means and methods of explosive detection, especially to the vapors and traces, is given for the reason, that the last are unique direct attributes of the presence of explosives at suspicious objects.

The coordination properties of two C₃-symmetry hexaza tripods, 1,3,5-tri(2,5-diazahexyl)benzene (L1) and 1,3,5-tri(2,5-diazaheptyl)benzene (L2), towards Zn²⁺, Cu²⁺, Ni²⁺ and Co²⁺ ions, studied by potentiometric techniques, are reported. Both ligands form quite stable complexes either in a 1:1 or 1:3 M:L stoichiometry, presenting a preferential coordination order: Zn²⁺ < Cu²⁺ > Ni²⁺ > Co²⁺. It is observed that the different configurations of metal complexes are achieved due to the fact that tripodal ligands are flexible and not constrained into a rigid geometry.

Pure and well crystallised whitlockite Ca₁₈Mg₂H₂(PO₄)₁₄ has been synthesized by precipitation from the magnesium and calcium nitrates and the diammonic phosphate. The product of the reaction has been characterized by X-ray diffraction, IR spectroscopy and chemical analysis. Using differential conduction calorimeters the enthalpies of solution of the whitlockite and of a mixture of the solid reactants - the tricalcium, the trimagnesium and the dicalcium phosphates - have been measured at 25°C for various concentrations of solid in a 46 wt% nitric acid solution. A combination of the enthalpies of solution with the enthalpies of formation of the reactants allows us to determine the standard enthalpy of formation of the whitlockite. The value deduced, -27,93·10³kJ mol^-1, is compared to the standard enthalpies of formation of the trimagnesium and the tricalcium phosphates.

The molecular conformations of 2,6-bis-(4-phenyl)benzylidene-3R-methyl-cyclohexanone and its mono-(4-phenyl)benzylidene methylcyclohexanone isomers were investigated by molecular simulation using the semiempirical AM1 and PM3 methods and by analyzing the experimental spin-spin coupling constants in the PMR spectra. Mesomorphism and the twisting ability of the induced cholesteric mesophases of the title compounds are analyzed using the ratios between conformers with the axial and equatorial methyl groups and other peculiarities of the spatial structure of molecules (differences in anisometricity and in the degree of flattening of the cinnamoyl fragment). The equatorial orientation of the methyl group in the dominant conformations generally favors the formation of mesophases. The twisting ability is higher for chiral compounds with an axial methyl substituent and with the chiral center directly bonded to the enone and arylidene groups.

The thermal characterization (DSC and TG) of benzylcellulose derivatives prepared from the benzylation of bleached Pinus Kraft pulp is described in this paper. The objective of this study was to examine the changes in glass transition temperature (T_g) and the thermal stability of the benzylated product as a function of the benzylation extent (degree of substitution). The DSC analysis showed that the benzylcelluloses can display glass transition temperature at two different regions and that thermal stability is slightly higher than that of the parent cellulose.