608 research outputs found
Development and Validation of Spectrophotometric, Atomic Absorption and Kinetic Methods for Determination of Moxifloxacin Hydrochloride
Three simple spectrophotometric and atomic absorption spectrometric methods are developed and validated for the determination of moxifloxacin HCl in pure form and in pharmaceutical formulations. Method (A) is a kinetic method based on the oxidation of moxifloxacin HCl by Fe3+ ion in the presence of 1,10 o-phenanthroline (o-phen). Method (B) describes spectrophotometric procedures for determination of moxifloxacin HCl based on its ability to reduce Fe (III) to Fe (II), which was rapidly converted to the corresponding stable coloured complex after reacting with 2,2âČ bipyridyl (bipy). The formation of the tris-complex formed in both methods (A) and (B) were carefully studied and their absorbance were measured at 510 and 520 nm respectively. Method (C) is based on the formation of ion- pair associated between the drug and bismuth (III) tetraiodide in acidic medium to form orangeâred ion-pair associates. This associate can be quantitatively determined by three different procedures. The formed precipitate is either filtered off, dissolved in acetone and quantified spectrophotometrically at 462 nm (Procedure 1), or decomposed by hydrochloric acid, and the bismuth content is determined by direct atomic absorption spectrometric (Procedure 2). Also the residual unreacted metal complex in the filtrate is determined through its metal content using indirect atomic absorption spectrometric technique (procedure 3). All the proposed methods were validated according to the International Conference on Harmonization (ICH) guidelines, the three proposed methods permit the determination of moxifloxacin HCl in the range of (0.8â6, 0.8â4) for methods A and B, (16â96, 16â96 and 16â72) for procedures 1â3 in method C. The limits of detection and quantitation were calculated, the precision of the methods were satisfactory; the values of relative standard deviations did not exceed 2%. The proposed methods were successfully applied to determine the drug in its pharmaceutical formulations without interference from the common excipients. The results obtained by the proposed methods were comparable with those obtained by the reference method
Radiation-Induced Leiomyosarcoma after Breast Cancer Treatment and TRAM Flap Reconstruction
The development of a radiation-induced sarcoma (RIS) in the post mastectomy thoracic treatment volume is an infrequent, but recognized, event. Its frequency is rising in relation with increasing survival of breast cancer patients treated with adjuvant radiation therapy, and is associated with poor prognosis despite treatment.
We present a case of leiomyosarcoma in a patient who underwent mastectomy followed by radiotherapy for invasive ductal carcinoma. A delayed TRAM flap reconstruction was performed 10 years after and a rapid growing mass under the reconstructed flap appeared, on routine follow-up, twenty years later. This report analyzes the diagnostic and therapeutic approach of patients with RIS
High-Energy Gamma-Ray Observations of Two Young, Energetic Radio Pulsars
We present results of Compton Gamma-Ray Observatory EGRET observations of the
unidentified high-energy gamma-ray sources 2EG J1049-5847 (GEV J1047-5840, 3EG
J1048-5840) and 2EG J1103-6106 (3EG J1102-6103). These sources are spatially
coincident with the young, energetic radio pulsars PSRs B1046-58 and
J1105-6107, respectively. We find evidence for an association between PSR
B1046-58 and 2EG J1049-5847. The gamma-ray pulse profile, obtained by folding
time-tagged photons having energies above 400 MeV using contemporaneous radio
ephemerides, has probability of arising by chance of 1.2E-4 according to the
binning-independent H-test. A spatial analysis of the on-pulse photons reveals
a point source of equivalent significance 10.2 sigma. Off-pulse, the
significance drops to 5.8 sigma. Archival ASCA data show that the only hard
X-ray point source in the 95% confidence error box of the gamma-ray source is
spatially coincident with the pulsar within the 1' uncertainty (Pivovaroff,
Kaspi & Gotthelf 1999). The double peaked gamma-ray pulse morphology and
leading radio pulse are similar to those seen for other gamma-ray pulsars and
are well-explained in models in which the gamma-ray emission is produced in
charge-depleted gaps in the outer magnetosphere. The inferred pulsed gamma-ray
flux above 400 MeV, (2.5 +/- 0.6) x 10E-10 erg/cm^2/s, represents 0.011 +/-
0.003 of the pulsar's spin-down luminosity, for a distance of 3 kpc and 1 sr
beaming. For PSR J1105-6107, light curves obtained by folding EGRET photons
using contemporaneous radio ephemerides show no significant features. We
conclude that this pulsar converts less than 0.014 of its spin-down luminosity
into E > 100 MeV gamma-rays beaming in our direction (99% confidence), assuming
a distance of 7 kpc, 1 sr beaming and a duty cycle of 0.5.Comment: Accepted for publication in the Astrophysical Journa
Detection of 33.8 ms X-ray pulsations in SAX J0635+0533
We revisited the BeppoSAX observation of SAX J0635+0533, suggested as a
possible counterpart to the gamma-ray source
2EG J0635+0521. We have discovered a 33.8 ms pulsation from the source and
derived an improved position, consistent with the location of the Be star
proposed as a binary companion.
We interpret the periodicity as the spin period of a neutron star in a binary
system with a Be companion.Comment: 13 pages, LaTeX, 5 PS figures, requires aasms4,apjfonts,psfig styles,
accepted for publication on ApJ Letter
3EG J2027+3429 another Blazar behind the Galactic Plane
We report on the association of an X-ray source (WGA J2025.1+3342),
serendipitously found with BeppoSAX in two separate observations, with the
unidentified EGRET source 3EG J2027+3429. The source is detected from 1 keV up
to about 100 keV, has a flat (0.6-1.5) spectrum and is highly variable both in
intensity and shape. The data indicate marginal evidence for an iron line in
the source rest frame. The overall X-ray luminosity is 4 10^{45} erg s^{-1}
typical of a quasar. The X-ray source is coincident in radio with a bright
object characterized by a flat spectrum over the band 0.3-10 GHz while in
optical it is identified with a quasar at redshift 0.22. All available data
indicate a SED compatible with a low frequency peaked or red blazar type
object. This identification is interesting because this is the second blazar
found behind the galactic plane in the direction of the Cygnus region.Comment: 6 pages, 5 figures, 3 tables, accepted for publication in A&
Study of the Composite Supernova Remnant MSH 11-62
We present the analysis of the X-ray data collected during an observation of
the supernova remnant (SNR) MSH 11-62 by the Advanced Satellite for Cosmology
and Astrophysics (ASCA). We show that MSH 11-62 is a composite remnant whose
X-ray emission comes from two distinct contributions. Nonthermal, synchrotron
emission, localized to a region of radius (~~)3' (consistent with a point
source) dominates the total flux above 2 keV. A second contribution comes from
a thermal component, extended up to a radius of (~~)6' and detected only at
energies below 2keV. The spatial and spectral analysis imply the presence of a
neutron star losing energy at a rate of about (10**36 - 10**37) ergs/s. No
pulsed emission is detected and we set a limit on the pulsed fraction of 10%.
This is consistent with the lack of a radio pulsar in the remnant, which may
indicate that the pulsed emission from the rapidly rotating compact object that
should be powering the synchrotron nebula is beamed and our viewing direction
is unfavorable. In either event, the central neutron star deposits much of its
spin-down energy into the surrounding synchrotron nebula where, through direct
imaging with broadband satellites such as ASCA, it is possible to study the
energetics and evolution of the compact remnant.Comment: 30 pages, including 5 figures, Latex. To appear in ApJ (May 20, 1998
issue, Vol. 499.
A luminosity constraint on the origin of unidentified high energy sources
The identification of point sources poses a great challenge for the high
energy community. We present a new approach to evaluate the likelihood of a set
of sources being a Galactic population based on the simple assumption that
galaxies similar to the Milky Way host comparable populations of gamma-ray
emitters. We propose a luminosity constraint on Galactic source populations
which complements existing approaches by constraining the abundance and spatial
distribution of any objects of Galactic origin, rather than focusing on the
properties of a specific candidate emitter. We use M31 as a proxy for the Milky
Way, and demonstrate this technique by applying it to the unidentified EGRET
sources. We find that it is highly improbable that the majority of the
unidentified EGRET sources are members of a Galactic halo population (e.g.,
dark matter subhalos), but that current observations do not provide any
constraints on all of these sources being Galactic objects if they reside
entirely in the disk and bulge. Applying this method to upcoming observations
by the Fermi Gamma-ray Space Telescope has the potential to exclude association
of an even larger number of unidentified sources with any Galactic source
class.Comment: 18 pages, 4 figures, to appear in JPhys
MAGIC observations of very high energy gamma-rays from HESS J1813-178
Recently, the HESS collaboration has reported the detection of gamma-ray
emission above a few hundred GeV from eight new sources located close to the
Galactic Plane. The source HESS J1813-178 has sparked particular interest, as
subsequent radio observations imply an association with SNR G12.82-0.02.
Triggered by the detection in VHE gamma-rays, a positionally coincident source
has also been found in INTEGRAL and ASCA data. In this Letter we present MAGIC
observations of HESS J1813-178, resulting in the detection of a differential
gamma-ray flux consistent with a hard-slope power law, described as dN/(dA dt
dE) = (3.3+/-0.5)*10^{-12} (E/TeV)^{-2.1+/-0.2} cm^(-2)s^(-1)TeV^(-1). We
briefly discuss the observational technique used, the procedure implemented for
the data analysis, and put this detection in the perspective of multifrequency
observations.Comment: Accepted by ApJ Letter
Young Women and Consumer Culture
This article is presented as an intervention in the field of feminist media and cultural studies with particular reference to consumer culture. It is concerned with the seeming evasion of critique which can be detected in a number of recent feminist responses to the way in which modalities of âpopular feminismâ have found themselves incorporated into women's genres of television, such as, in particular, the US series Sex in the City. This usage or instrumentalization of feminism (in its most conventionally liberal feminist guise) also provides corporate culture with the means of presenting itself to young women as their ally and even champion of âgirlsâ while at the same time earning seeming approval for adopting the mantle of social responsibility, which makes the concept of popular feminism more problematic than it first appeared. Such appropriation of popular feminist discourse by the commercial domain prompts a self-critique on the part of the author alongside an analysis of recent approaches toward consumer culture in cultural studies. The article continues by presenting a schematic account of how the commercial domain increasingly supplants state and public sector institutions in the intensity and dedication of its address to girls and young women. Whilst some may argue that the intersection of youthful femininity and the commercial sphere is not a new phenomenon, what is being explored here is the connection between this intensification of attention and the logic of current neo-liberal economic rationalities. The argument is, therefore, that it is by these means including the instrumentalization of a specific modality of âfeminismâ that there emerges into existence a neo-liberal culture, with global aspirations, which has as its ideal subject the category of âgirlâ
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