Glucose and glutamine metabolism of a murine B-lymphocyte hybridoma grown in batch culture

The energy metabolism of a mammalian cell line grown in vitro was analyzed by substrate consumption rates and metabolic flux measurements. The data allowed the determination of the relative importance of the pathways of glucose and glutamine metabolism to the energy requirements of the cell. Changes in the substrate concentrations during culture contributed to the changing catalytic activities of key enzymes, which were determined.

Ionic hydrates,M(p)X(q).nH(2)O: lattice energy and standard enthalpy of formation estimation

This paper is one of a series (see: Inorg. Chem. 1999, 38, 3609; J. Am. Chem. Soc. 2000, 122, 632; Inorg. Chem. 2002, 41, 2364) exploring simple approaches for the estimation of lattice energies of ionic materials, avoiding elaborate computation. Knowledge of lattice energy can lead, via thermochemical cycles, to the evaluation of the underlying thermodynamics involving the preparation and subsequent reactions of inorganic materials. A simple and easy to use equation for the estimation of the lattice energy of hydrate salts, U(POT)(M(p)X(q).nH(2)O) (and therefore for solvated salts, M(p)X(q).nS, in general), using either the density or volume of the hydrate, or of another hydrate, or of the parent anhydrous salt or the volumes of the individual ions, is derived from first principles. The equation effectively determines the hydrate lattice energy, U(POT)(M(p)X(q).nH(2)O), from a knowledge of the (estimated) lattice energy, U(POT)(M(p)X(q)), of the parent salt by the addition of ntheta(U) where theta(U)(H(2)O)/kJ mol(-1) = 54.3 and n is the number of water molecules. The average volume of the water molecule of hydration, V(m)(H(2)O)/nm(3) = 0.0245, has been determined from data on a large series of hydrates by plotting hydrate/parent salt volume differences against n. The enthalpy of incorporation of a gaseous water molecule into the structure of an ionic hydrate, [Delta(f)H degrees (M(p)X(q).nH(2)O,s) - Delta(f)H degrees (M(p)X(q),s) - nDelta(f)H degrees (H(2)O,g)], is shown to be a constant, -56.8 kJ (mol of H(2)O)(-1). The physical implications with regard to incorporation of the water into various types of solid-state structures are considered. Examples are given of the use of the derived hydrate lattice energy equation. Standard enthalpies of formation of a number of hydrates are thereby predicted.     

Determination of cocaine and heroin vapor pressures using commercial and illicit samples

The establishment of drug vapor pressure reference values provides valuable information in the development of vapor sensing devices for drug detection. The purpose of this work was to determine equilibrium headspace vapor pressures for commercial and illicit drug samples for use in such applications. Samples of cocaine, both free base and hydrochloride forms, and heroin hydrochloride were evaluated. The procedure used to measure the vapor pressures was a modification of a previously published method. Vapor pressure values at 20 degrees C previously reported for cocaine free base range from 0.37 x 10(-7) to 1.20 x 10(-7) Torr. The vapor pressure value determined in this study was 2.96 x 10(-7) Torr. It is likely that the discrepancies are due to differences in experimental conditions, varying sources of samples, and uncertainty in the methodologies. When the values were compared for commercial (99% purity) and illicit (unknown purity) sources of cocaine free base, there were no statistical differences in the projected room temperature (20 degrees C) vapor pressure values. However, the commercial and illicit samples of cocaine hydrochloride did show statistical differences. Although no comparison was made with the vapor pressure values for a pure, commercial sample, the vapor pressures of heroin hydrochloride (81% purity) at various temperatures were determined using the method developed for cocaine and are reported in this paper.     

Heating process characteristics and kinetics of sewage sludge in different atmospheres

The treatment of wastewater generates a by-product, sewage sludge, the disposal of which poses problems. There are, however, a number of options for making use of this residue, including its conversion into a valuable fuel. The aim of this paper is to describe the process of the heating of sewage sludge under different atmospheres of helium and oxygen and to obtain the kinetic parameters by means of a mathematical model, a heating rate of 10 °C/min being used. Measurements were taken by thermogravimetry and mass spectrometry, and proximate and elementary analyses were made of the sludges and their calorific values were determined. Visual observation of the heating profiles shows four stages in the heating process, which have been characterized. The model proposed was found to adequately describe the weight loss of the sludges studied, while making it possible to obtain the kinetic parameters for the differentiated stages in the thermal process but not to establish any clear tendency of the evolution of these parameters with the increase in oxygen in the heating atmosphere.     

The initiation of polymerization by organometallic compounds—IV. Initiator efficiency in polymerization of acrylonitrile by tetrakis(dimethylamido)titanium(JV)

A titrimetric method has been developed for following the removal of titanium-dimethylamine bonds during the polymerization of acrylonitrile by tetrakis(dimethylamido)titanium(IV) (T₄). The kinetics of the reaction of T₄ with monomer can be interpreted in terms of a sequence of insertion reactions in which dimethylamino ligands are successively removed from titanium. The calibration of a GPC instrument for measurement of the molecular weights of polyacrylonitrile is discussed. The results of initiator consumption and polymer molecular weight measurements are combined to allow the efficiency of initiation by T₄ to be assessed. Over the whole conversion range, titanium-dimethylamine bonds are broken in about 50 per cent excess over those used for polymerization. However, at high conversions more than one polymer chain is produced per titanium atom reacted.     

Synthesis, structures and rac/meso isomerization behaviour of bisplanar chiral bis(phosphino-η-indenyl)iron(II) complexes

Syntheses of the phosphinoindenes 1-(diphenylphosphino)-3-methylindene (1b), 3-(diphenylphosphino)-2-methylindene (1c), 1-(diphenylphosphino)-2,3-dimethylindene (1d), 4,7-dimethyl-3-(diphenylphosphino)indene (1e), 1-(diphenylphosphino)-3,4,7-trimethylindene (1f) and 3-(diisopropylphosphino)indene (1i) were carried out by treatment of the appropriate indenide with the appropriate chlorophosphine. The silylphosphinoindene 3-(diphenylphosphino)-1-(trimethylsilyl)indene (1h) was prepared by treatment of the indenide of 3-(diphenylphosphino)indene (1a) with trimethylsilylchloride. These indenes, in addition to 1a, were then used, after deprotonation with BuLi, to prepare the corresponding indenyl ferrocenes, 2a-2e, 2h and 2i, by treatment with ferrous chloride in a 2:1 ratio. These compounds were characterized by ¹H, ¹³C, and ³¹P NMR spectroscopy, as well as by mass spectrometry, except for the highly-sensitive diisopropylphosphine 2i that could only be characterized by ³¹P NMR spectroscopy. All of these ferrocene complexes are bisplanar chiral systems that can potentially form rac and meso isomers. In all cases both isomers were observed but for 2b and 2h only one could be isolated. The rac isomers of complexes 2a, 2b, 2d, and 2e, as well as the meso isomer of 2e, were studied by X-ray crystallography. Only complexes 2a and 2i were observed to undergo rac/meso isomerization processes at ambient temperature in THF solvent. We were unable to prepare the sterically congested hexamethylferrocene 2f. Generally, it was found that increasing substitution on the indenyl ring increases the reactivity and sensitivity of the ferrocene.     

The structure of the chiral Pt531 surface: a combined LEED and DFT study

The structure of the chiral kinked Pt531 surface has been determined by low-energy electron diffraction intensity-versus-energy (LEED-IV) analysis and density functional theory (DFT). Large contractions and expansions of the vertical interlayer distances with respect to the bulk-terminated surface geometry were found for the first six layers (LEED: d12 = 0.44 A, d23 = 0.69 A, d34 = 0.49 A, d45 = 0.95 A, d56 = 0.56 A; DFT: d12 = 0.51 A, d23 = 0.55 A, d34 = 0.74 A, d45 = 0.78 A, d56 = 0.63 A; dbulk = 0.66 A). Energy-dependent cancellations of LEED spots over unusually large energy ranges, up to 100 eV, can be explained by surface roughness and reproduced by applying a model involving 0.25 ML of vacancies and adatoms in the scattering calculations. The agreement between the results from LEED and DFT is not as good as in other cases, which could be due to this roughness of the real surface.     

A computational study of SbnF5n (n = 1-4): Implications for the fluoride ion affinity of nSbF5

This contributions shows with a series of ab initio MP2 and DFT (BP86 and B3-LYP) computations with large basis sets up to cc-pVQZ quality that the literature value of the standard enthalpy of depolymerization of Sb₄F_20(g) to give SbF_5(g) (+18.5 kJ mol⁻¹) [J. Fawcett, J.H. Holloway, R.D. Peacock, D.R. Russell, J. Fluorine Chem. 20 (1982) 9] is by about 50 kJ mol⁻¹ in error and that the correct value of (Sb₄F_20(g)) is +68 ± 10 kJ mol⁻¹. We assign , , and values for Sb_nF_5n with n = 2-4 and compare the results to available experimental gas phase data. Especially the MP2/TZVPP values obtained in an indirect procedure that rely on isodesmic reactions or the highly accurate compound methods G2 and CBS-Q are in excellent agreement with the experimental data, and reproduce also the fine experimental details at temperatures of 423 and 498 K. With these data and the additional calculation of [Sb_nF_5n+1]⁻ (n = 1-4), we then assessed the fluoride ion affinities (FIAs) of Sb_nF_5n(g), nSbF_5(g), nSbF_5(l) and the standard enthalpies of formation of Sb_nF_5n(g) and [Sb_nF_5n+1]⁻_(g): FIA(Sb_nF_5n(g)) = 514 (n = 1), 559 (n = 2), 572 (n = 3) and 580 (n = 4) kJ mol⁻¹; FIA(nSbF_5(g)) = 667 (n = 2), 767 (n = 3) and 855 (n = 4) kJ mol⁻¹; FIA(nSbF_5(l)) = 434 (n = 1), 506 (n = 2), 528 (n = 3) and 534 (n = 4) kJ mol⁻¹. Error bars are approximately ±10 kJ mol⁻¹. Also the related Gibbs energies were derived. Δ_fH°([Sb_nF_5n+1]⁻_(g)) = −2064 ± 18 (n = 1), −3516 ± 25 (n = 2), −4919 ± 31 (n = 3) and −6305 ± 36 (n = 4) kJ mol⁻¹.     

Base- and Co(II)-catalyzed ring-opening reactions of perhydrooxireno[2,3-d][1,2]dioxines: an efficient route to 4-hydroxy-2,3-epoxy-ketones

A series of 3,4,6-substituted 3,6-dihydro-1,2-dioxines were epoxidized with m-chloroperbenzoic acid to furnish perhydrooxireno[2,3-d][1,2]dioxines (epoxy-1,2-dioxines) in yields ranging from 51% to 93% with de's from 26% to 100%. Unsymmetrical epoxy-1,2-dioxines were ring-opened using triethylamine to yield 4-hydroxy-2,3-epoxy-ketones quantitatively, and meso-epoxy-1,2-dioxines were ring-opened using Co(II) salen complexes to afford 4-hydroxy-2,3-epoxy-ketones in 77-98% yield. The first reported examples of the catalytic asymmetric ring-opening of meso-epoxy-1,2-dioxines using a range of chiral Co(II) salen and beta-ketoiminato complexes to afford highly enantio-enriched 4-hydroxy-2,3-epoxy-ketones are also presented.     

PHOTOBIOLOGICAL PROPERTIES OF A NOVEL, NATURALLY OCCURRING FUROISOCOUMARIN, CORIANDRIN

The photobiological properties of a novel, naturally occurring furoisocoumarin isolated from coriander and named coriandrin are described. Photosensitized lethal and mutagenic effects in bacteria indicate that it is more active than psoralen. It is a weak frameshift mutagen in the dark. Mammalian cells in tissue culture are photosensitized more actively with coriandrin than with psoralen even though preliminary evidence from interrupted radiation experiments and DNA analysis suggest that coriandrin does not form DNA interstrand crosslinks. Sister chromatid exchanges were induced with a unit dose of 1.1 x 10(-2) with coriandrin; the value for psoralen is 3 x 10(-3). Coriandrin appears to be metabolized more rapidly than furocoumarins by liver mixed function oxidases. Skin photosensitizing activity is very weak compared with psoralen, a surprising observation considering its potency in biological test systems.