Bioactive flavanones from Luma chequen

A bioassay-guided chemical study of a methanolic extract of fresh leaves of Luma chequen led to the isolation of lumaflavanones A (1), B (2) and C (3) whose structures are proposed on the basis of NMR spectroscopic data. The structure of lumaflavanone A was confirmed by X-ray analysis. Antifeedant (Spodoptera littoralis), brine shrimp (Artemia salina) and fungistatic (Botrytis cinerea) bioassays showed that while 3 was the most active in the first two assays the mixture of 1 and 2 was more effective as a fungistatic

Investigation of Dynamics of Self-Similarly Evolving Magnetic Clouds

Magnetic clouds (MCs) are "magnetized plasma clouds" moving in the solar wind. MCs transport magnetic flux and helicity away from the Sun. These structures are not stationary but feature temporal evolution. Commonly, simplified MC models are considered. The goal of the present study is to investigate the dynamics of more general, radially expanding MCs. They are considered as cylindrically symmetric magnetic structures with low plasma {\beta}. In order to study MC`evolution the self-similar approach method and a numerical approach are used. It is shown that the forces are balanced in the considered self-similarly evolving, cylindrically symmetric magnetic structures. Explicit analytical expressions for magnetic field, plasma velocity, density and pressure within MCs are derived. These solutions are characterized by conserved values of magnetic flux and helicity. We also investigate the dynamics of self-similarly evolving MCs by means of the numerical code "Graale". In addition, their expansion in a medium with higher density and higher plasma {\beta} is studied. It is shown that the physical parameters of the MCs maintain their self-similar character throughout their evolution. Conclusions. A comparison of the different self-similar and numerical solutions allows us to conclude that the evolving MCs are quite adequately described by our self-similar solutions - they retain their self-similar, coherent nature for quite a long time and over large distances from the Sun

2-{[{2-Hy­droxy-3-[2-methyl-5-(propan-2-yl)phen­oxy]prop­yl}(pyridin-2-ylmeth­yl)amino]­meth­yl}phenol

In the title racemic compound, C26H32N2O3, an intra­molecular O—H⋯N hydrogen bond is formed between the phenolic OH group and the tertiary amine N atom. Another O—H⋯N hydrogen bond that is formed between the OH group and the pyridine N atom links the mol­ecules into a polymeric chain extending along the a axis. The structure is further stabilized by intramolecular and intermolecular C—H⋯O interactions

PACE and EISCAT radar observations of short-lived flow bursts on the nightside

Concurrent observations from two widely spaced radar experiments of quasi periodic flow bursts in the nightside are presented. The flow bursts closely resemble single radar observations reported by Williams et al. By using the Polar Anglo-American Conjugate Experiment (PACE) HF radar array at Halley Bay in conjunction with the EISCAT Common Program (CP) 2-D experiment, the flow bursts are shown to be a global phenomenon and important information as to their development and propagation can be determined

Progressive transformation of a flux rope to an ICME

The solar wind conditions at one astronomical unit (AU) can be strongly disturbed by the interplanetary coronal mass ejections (ICMEs). A subset, called magnetic clouds (MCs), is formed by twisted flux ropes that transport an important amount of magnetic flux and helicity which is released in CMEs. At 1 AU from the Sun, the magnetic structure of MCs is generally modeled neglecting their expansion during the spacecraft crossing. However, in some cases, MCs present a significant expansion. We present here an analysis of the huge and significantly expanding MC observed by the Wind spacecraft during 9 and 10 November, 2004. After determining an approximated orientation for the flux rope using the minimum variance method, we precise the orientation of the cloud axis relating its front and rear magnetic discontinuities using a direct method. This method takes into account the conservation of the azimuthal magnetic flux between the in- and out-bound branches, and is valid for a finite impact parameter (i.e., not necessarily a small distance between the spacecraft trajectory and the cloud axis). Moreover, using the direct method, we find that the ICME is formed by a flux rope (MC) followed by an extended coherent magnetic region. These observations are interpreted considering the existence of a previous larger flux rope, which partially reconnected with its environment in the front. These findings imply that the ejected flux rope is progressively peeled by reconnection and transformed to the observed ICME (with a remnant flux rope in the front part).Comment: Solar Physics (in press

4-Chloro­anilinium hydrogen oxalate hemihydrate

In the title hydrated mol­ecular salt, C6H7ClN+·C2HO4 −·0.5H2O, the water O atom lies on a crystallographic twofold axis. In the crystal, the anions are linked by O—H⋯O hydrogen bonds, forming chains propagating along the b axis. These chains are inter­connected through O—H⋯O hydrogen bonds from the water mol­ecules and N—H⋯O hydrogen bonds from the cations, building layers parallel to the ab plane

(4-Chloro­phen­yl)methanaminium chloride hemihydrate

In the title hydrated salt, C7H9ClN+·Cl−·0.5H2O, the water O atom lies on a crystallographic twofold axis. In the crystal, the monoprotonated 4-chloro­benzyl­ammonium cation forms N—H⋯Cl and N—H⋯O hydrogen bonds and the water mol­ecule forms O—H⋯Cl hydrogen bonds, generating layers lying parallel to the bc plane

The role of alpha particles in the emission of plasma waves inside solar ejecta

The enhancement of the resonant instability of right-hand polarized electromagnetic ion cyclotron waves by alpha particles for physical parameters corresponding to coronal mass ejections is studied. We focus on the effects of alpha thermal anisotropy and relative He++/H+ abundance on growth and absorption rates. The first parameter governs directly wave emission, while the second modifies also the wave speed and indirectly enhances the wave excitation

Dibenzyl ferrocene-1,1′-dicarboxyl­ate

In the title compound, [Fe(C13H11O2)2], there are markedly different orientations of the two phenyl­meth­oxy­carbonyl substituents [O—C—C—C torsion angles = 84.5 (3) and 139.6 (2)°]. These orientations are mediated by a number of inter­molecular C—H⋯O inter­actions, which result in a one-dimensional hydrogen-bonded network of mol­ecules

2-Amino­pyrimidinium dihydrogen phosphate monohydrate

In the title compound, C4H6N3 +·H2O4P−·H2O, the pyrimidin­ium ring is essentially planar, with an r.m.s. deviation of 0.0016 Å. In the structure, pairs of symmetry-related anions are connected into centrosymmetric clusters via strong O—H⋯O hydrogen bonds forming six-membered rings with an R 2 2(6) motif. These clusters are inter­connected via water mol­ecules through OW—H⋯O hydrogen bonds, building an infinite layer parallel to the ab plane. Moreover, infinite chains of 2-amino­pyrimidinium cations spread along the a-axis direction. These chains are connected to the inorganic layer through N—H⋯O, C—H⋯O and C—H⋯N hydrogen bonds, which, together with electrostatic and van der Waals inter­actions, contribute to the cohesion and stability of the network in the crystal structure