A stereoselective synthesis for the (5Z,9Z)-14-methyl-5,9-pentadecadienoic acid and its monounsaturated analog (Z)-14-methyl-9-pentadecenoic acid

A stereoselective synthesis for the (5Z,9Z)-14-methyl-5,9-pentadecadienoic acid and the monounsaturated analog (Z)-14-methyl-9-pentadecenoic acid was accomplished in six to seven steps where double alkyne coupling was the key step. This synthesis will facilitate the study of the topoisomerase I inhibitory profile of this important class of fatty acids.     

17α-acetoxy-17β-methyl-16β-phenyl-D-homo-4,6-pregnadiene-3,17a-dione: synthesis and crystal structure determination of a new rearranged pregnane derivative

The title compound is C₂₉H₃₄O₄, tetragonal, P4₃, a = b = 10.310(1), c = 23.871(2)Å. The A, B, C, and D rings adopt envelope, half-chair, chair, and distorted chair conformations, respectively. The phenyl ring is planar. The methyl substituents at the A/B, C/D, and at C(17) are axial; and the –OCOCH₃ group at C(17) and phenyl ring at C(16) are equatorial. The molecules in the crystal are held together by van der Waals forces and several C–H···O hydrogen bond interactions.     

Phytochemical Constituents and Ameliorative Effect of the Essential Oil from Annona muricata L. Leaves in a Murine Model of Breast Cancer

Annona muricata leaves are traditionally used as an anticancer plant in the world. The aim of this study was to evaluate the ameliorative effect of the essential oil from Annona muricata leaves (EOAm) in an experimental model of breast cancer and to determine the volatile constituents with gas chromatography-mass spectrometry (GC-MS). Thirty female rats were assigned to five groups: the control group; the DMBA (7,12-dimethylbenz[α]anthracene) group; and three groups received daily EOAm doses of 50, 100, and 200 mg/kg/day, plus DMBA, respectively. After 13 weeks of treatment, tumors were analyzed pathologically and biochemical markers in serum were noted. As a result, in GC-MS analysis, 40 compounds were identified and 4 of them were abundant: Z-caryophyllene (40.22%), followed by α-selinene (9.94%), β-pinene (8.92%), and β-elemene (7.48%). Furthermore, EOAm in a dose-dependent form produced a reduction in tumor frequency and the accumulated tumor volume was reduced by 50% and 71% with doses of 100 and 200 mg/kg, respectively. Serum levels of reduced glutathione (GSH) increased and malondialdehyde (MDA) decreased significantly compared to the DMBA group. Serum levels of vascular endothelial growth factor (VEGF) decreased significantly from 70.75 ± 7.15 pg/mL in the DMBA group to 46.50 ± 9.00 and 34.13 ± 11.50 pg/mL in groups treated with doses of 100 and 200 mg/kg, respectively. This study concludes that the EOAm leaves showed an ameliorative effect in a murine model of breast cancer.     

Unification of Spins and Charges

Polynomials in Grassmann algebra can be used to describe the internal degrees, spins and charges of spinors, scalars, and vectors. It was shown by Manko Bortnik and Nielsen that Kähler spinors can be generalized to describe spins of vectors as well as spins and charges of scalars, vectors, and spinors. In dimensions 14 and higher, the spontaneous breaking of symmetry leads gravity in d dimensions to manifest in 4-dimensional subspace as ordinary gravity and all needed gauge fields as well as the Yukawa couplings. Both approaches, Kähler's one (if generalized) and ours, manifest four generations of massless fermions, which are left-handed SU(2) doublets and right-handed SU(2) singlets. A possible way of spontaneously breaking symmetries is pointed out at the level of canonical momentum.     

Necessary conditions for the neutral problem of Bolza with continuously varying time delay

This note uses Clarke's decoupling technique to obtain necessary conditions for the generalized problem of Bolza with Lipschitz continuously varying delay in both the state and velocity variables.     

The interaction of morpholine with metal ions—I: Copper complexes

The synthesis and electronic and IR spectra of CuL₂(NO₃)₂ and CuL₄(NO₃)₂, where L stands for morpholine, are described. The thermal behaviour of the complexes is also discussed. The solids contain distorted octahedral Cu(II) bonded to morpholine through nitrogen only. In aqueous solutions only the species CuL₃(aq)²⁺ is stable in the concentration range 0.5 < [L] < 2 mol dm^?3, its stability constant being log K₃ = 14.64 ± 0.15 at 25.00°C and ionic strength 1 mol dm^?3; at very high morpholine concentrations, 3.4 < [L] < 6 mol dm^?3, evidence is also found for CuL₄(aq)²⁺, the value log K₄ = 15.5 being estimated. The aggressiveness of morpholine-H₂O₂ towards metallic copper is compared with that of ammonia-H₂O₂, both on thermodynamics and kinetics grounds; experimental results seems to be dominated by kinetics factors. The relevance of these results to water treatment in secondary systems of nuclear power reactors is discussed.     

Combustion synthesis and characterization of nanocrystalline WO3

The energy payback time associated with the semiconductor active material is an important parameter in a photovoltaic solar cell device. Thus lowering the energy requirements for the semiconductor synthesis step or making it more energy-efficient is critical toward making the overall device economics more competitive relative to other nonpolluting energy options. In this communication, combustion synthesis is demonstrated to be a versatile and energy-efficient method for preparing inorganic oxide semiconductors such as tungsten trioxide (WO3) for photovoltaic or photocatalytic solar energy conversion. The energy efficiency of combustion synthesis accrues from the fact that high process temperatures are self-sustained by the exothermicity of the combustion process, and the only external thermal energy input needed is for dehydration of the fuel/oxidizer precursor mixture and bringing it to ignition. Importantly, we show that, in this approach, it is also possible to tune the optical characteristics of the oxide semiconductor (i.e., shift its response toward the visible range of the electromagnetic spectrum) in situ by doping the host semiconductor during the formative stage itself. As a bonus, the resultant material shows enhanced surface properties such as markedly improved organic dye uptake relative to benchmark samples obtained from commercial sources. Finally, this synthesis approach requires only very simple equipment, a feature that it shares with other "mild" inorganic semiconductor synthesis routes such as sol-gel chemistry, chemical bath deposition, and electrodeposition. The present study constitutes the first use of combustion synthesis for preparing WO3 powder comprising nanosized particles.     

Molecular dynamics study of triosephosphate isomerase from Trypanosoma cruzi in water/decane mixtures

A comprehensive study of the triosephosphate isomerase from the parasite Trypanosoma cruzi (TcTIM) in water, in decane, and in three water/decane mixtures was performed using molecular dynamics (MD) simulations in a time scale of 40 ns. The structure and dynamics of the enzyme, as well as the solvent molecules' distribution and mobility, were analyzed in detail. In the presence of decane, the amplitudes of the most important internal motions of the enzyme backbone were observed to depend on the solvent concentration: the higher the water concentration, the greater the amplitudes. Contrary to this trend, the amplitudes of the TcTIM motions in pure water were similar to those of the simulation with the lowest water concentration. The enzyme was observed to be almost motionless in pure decane due to a sharp increase of the number of intramolecular hydrogen bonds. This caused a contraction of the enzyme structure accompanied by a loss of secondary structure and of a decrease of the hydrophilic solvent accessible surface. A similar behavior, although to a lesser extent, was observed in the simulation at the lowest water concentration. Our results suggest that the presence of decane molecules located at specific sites of the enzyme might accelerate its internal movements, although a minimum number of water molecules is needed for the protein to keep its structure and dynamics. Altogether, this work provides new insight into protein and water behavior in organic solvents as well as into the dynamics of TcTIM itself.