484 research outputs found
Synthetic Studies With Pinus Elliottiis' Rosin Derivatives. Oxidation Of Maleopimaric Anhydride Methyl Ester And Trimethyl Fumaropimarate
Ozonolysis of maleopimaric anhydride methyl ester in the presence of tetracyanoethylene led to an epoxide and an ozonide. Ozonolysis of the trimethyl fumaropimarate, followed by treatment with Me2S, led to an epoxide, a diene, a keto-acid and an allylic oxidation product. Some of the compounds obtained were active against Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus.1115963Seebacher, W., Hüfner, A., Haslingeer, E., Weis, R., (1995) Monatsh. Chem., 129, p. 697. , and references cited thereinKsabati, M.B., Schimtz, F.J., (1987) J. Org. Chem., 52, p. 3766Miyamoto, T., Sakamoto, K., Arao, K., Komori, T., Higuchi, R., Sasaki, T., (1996) Tetrahedron, 52, p. 8187Zalkow, L.H., Ford, R.A., Kutney, J.P., (1962) J. Org. Chem., 27, p. 3535Zalkow, L.H., Brannon, D.R., (1964) J. Org. Chem., 29, p. 1296Zalkow, L.H., Girotra, N.N., (1963) J. Org. Chem., 28, p. 2033Zalkow, L.H., Kulkarni, M.V., Girotra, N.N., (1965) J. Org. Chem., 30, p. 1679Halbrook, N.J., Lawrence, R.V., Dressler, R.L., Blackstone, R.C., Herz, W., (1964) J. Org. Chem., 29, p. 1017Santos, C., Rosso, C.R.S., Imamura, P., (1999) M. Synth. Commun., 29, p. 1903Bailey, P.S., (1978) Ozonization in Organic Chemistry, 1. , Academic Press, New YorkHerz, W., Blackstone, R.C., (1969) Atmos Environ, 34, p. 1257Atmos Environ, p. 135Masaki, Y., Miura, T., Ochiai, M., (1996) Bull. Chem. Soc. Jpn., 69, p. 195. , and references cited thereinThe ozonide could be stored in a freezer without decomposition at -5°C for few weeksShiojima, K., Masuda, K., Ageta, K., (1990) Chem. Pharm. Bull., 38, p. 79Li, T., Yang, Y., Li, Y., (1993) J. Chem. Res. (S), p. 30Carlsen, P.H.J., Katsuki, T., Martin, V.S., Sharpless, K.B., (1981) J. Org. Chem., 46, p. 3936Funk, R.L., Abelman, M.M., (1986) J. Org. Chem., 51, p. 3247For convenience, the numbering of carbons for 14 was used the same given for 3Sam, D.J., Simmons, H.F., (1972) J. Am. Chem. Soc., 94, p. 4024Ferreira, J.T.B., Cruz, W.O., Vieira, P.C., Yonashiro, M., (1987) J. Org. Chem., 52, p. 3698Mitra, R.B., Muljiani, Z., Deshmukh, A.R.A., (1982) S. Synth. Commun., 12, p. 1063Aristoff, P.A., Johnson, P.D., Harrison, A.W., (1985) J. Am. Chem. Soc., 107, p. 7961Homans, A.L., Fuchs, A., (1970) J. Chromatogr., 75, p. 327Hamburger, M.O., Cordell, G.A., (1987) J. Nat. Prod., 50, p. 19Bruch, M.K., (1991) Methods of Testing Antiseptics: Antimicrobials Used Topically in Humans and Procedures for Hand Scrubs, in Disinfection, Sterilization and Preservation, 4th. Ed., , Lea & Febinger, PhiladelphiaHalbrook, N.J., Lawrence, R.V., (1958) J. Am. Chem. Soc., 80, p. 36
Morphological and Structural Characterization of Cro2/Cr2o3 Films Grown by Laser-CVD
This work reports on the synthesis of chromium (III, IV) oxides films by KrF
laser-assisted CVD. Films were deposited onto sapphire substrates at room
temperature by photodissociation of Cr(CO)6 in dynamic atmospheres containing
oxygen and argon. A study of the processing parameters has shown that partial
pressure ratio of O2 to Cr(CO)6 and laser fluence are the prominent parameters
that have to be accurately controlled in order to co-deposit both crystalline
oxide phases. Films consistent with such a two-phase system were synthesised
for a laser fluence of 75 mJ cm-2 and a partial pressure ratio about 1.
PACS: 81.15.Fg, 81.15.Kk, 81.05.JeComment: 17 pages, 4 figure
Magnetoluminescence
Pulsar Wind Nebulae, Blazars, Gamma Ray Bursts and Magnetars all contain
regions where the electromagnetic energy density greatly exceeds the plasma
energy density. These sources exhibit dramatic flaring activity where the
electromagnetic energy distributed over large volumes, appears to be converted
efficiently into high energy particles and gamma-rays. We call this general
process magnetoluminescence. Global requirements on the underlying, extreme
particle acceleration processes are described and the likely importance of
relativistic beaming in enhancing the observed radiation from a flare is
emphasized. Recent research on fluid descriptions of unstable electromagnetic
configurations are summarized and progress on the associated kinetic
simulations that are needed to account for the acceleration and radiation is
discussed. Future observational, simulation and experimental opportunities are
briefly summarized.Comment: To appear in "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts
and Blazars: Physics of Extreme Energy Release" of the Space Science Reviews
serie
Atomic X-ray Spectroscopy of Accreting Black Holes
Current astrophysical research suggests that the most persistently luminous
objects in the Universe are powered by the flow of matter through accretion
disks onto black holes. Accretion disk systems are observed to emit copious
radiation across the electromagnetic spectrum, each energy band providing
access to rather distinct regimes of physical conditions and geometric scale.
X-ray emission probes the innermost regions of the accretion disk, where
relativistic effects prevail. While this has been known for decades, it also
has been acknowledged that inferring physical conditions in the relativistic
regime from the behavior of the X-ray continuum is problematic and not
satisfactorily constraining. With the discovery in the 1990s of iron X-ray
lines bearing signatures of relativistic distortion came the hope that such
emission would more firmly constrain models of disk accretion near black holes,
as well as provide observational criteria by which to test general relativity
in the strong field limit. Here we provide an introduction to this phenomenon.
While the presentation is intended to be primarily tutorial in nature, we aim
also to acquaint the reader with trends in current research. To achieve these
ends, we present the basic applications of general relativity that pertain to
X-ray spectroscopic observations of black hole accretion disk systems, focusing
on the Schwarzschild and Kerr solutions to the Einstein field equations. To
this we add treatments of the fundamental concepts associated with the
theoretical and modeling aspects of accretion disks, as well as relevant topics
from observational and theoretical X-ray spectroscopy.Comment: 63 pages, 21 figures, Einstein Centennial Review Article, Canadian
Journal of Physics, in pres
Flux Phase as a Dynamic Jahn-Teller Phase: Berryonic Matter in the Cuprates?
There is considerable evidence for some form of charge ordering on the
hole-doped stripes in the cuprates, mainly associated with the low-temperature
tetragonal phase, but with some evidence for either charge density waves or a
flux phase, which is a form of dynamic charge-density wave. These three states
form a pseudospin triplet, demonstrating a close connection with the E X e
dynamic Jahn-Teller effect, suggesting that the cuprates constitute a form of
Berryonic matter. This in turn suggests a new model for the dynamic Jahn-Teller
effect as a form of flux phase. A simple model of the Cu-O bond stretching
phonons allows an estimate of electron-phonon coupling for these modes,
explaining why the half breathing mode softens so much more than the full
oxygen breathing mode. The anomalous properties of provide a coupling
(correlated hopping) which acts to stabilize density wave phases.Comment: Major Revisions: includes comparisons with specific cuprate phonon
modes, 16 eps figures, revte
Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement
Background: Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research. Design: A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved. Results: Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients. Conclusions: This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified
Model-independent search for CP violation in D0→K−K+π−π+ and D0→π−π+π+π− decays
A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states K−K+π−π+ and π−π+π+π− is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fb−1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the K−K+π−π+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the π−π+π+π− final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
An analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at TeV
The inclusive transverse momentum () distributions of primary
charged particles are measured in the pseudo-rapidity range as a
function of event centrality in Pb-Pb collisions at
TeV with ALICE at the LHC. The data are presented in the range
GeV/ for nine centrality intervals from 70-80% to 0-5%.
The Pb-Pb spectra are presented in terms of the nuclear modification factor
using a pp reference spectrum measured at the same collision
energy. We observe that the suppression of high- particles strongly
depends on event centrality. In central collisions (0-5%) the yield is most
suppressed with at -7 GeV/. Above
GeV/, there is a significant rise in the nuclear modification
factor, which reaches for GeV/. In
peripheral collisions (70-80%), the suppression is weaker with almost independently of . The measured nuclear
modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/284
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