2,159 research outputs found
Endocrine and Cell Surface Receptor Signaling in Breast Carcinogenesis
Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer-related death in female. To better understand the growth and progression as well as therapeutic management, breast cancers are grouped based on histopathological and molecular classification. A number of factors have been implicated in the development of breast cancer. Various cell surface as well as hormone receptor signaling play crucial role in breast cancer initiation and progression. This chapter briefly discusses few of the important receptor signaling pathways and the various strategies in practice as well as at different stages of development to target these pathways
Assessment of bioavailability of some potential toxic metals in mining-affected soils using EDTA extraction and principle component analysis (PCA) approach, Derbyshire, UK
The current study area has long mining history for copper, lead, and zinc. As a result, these metals may have elevated levels and pose a potential risk to the surrounding area. This area is currently being used for agriculture and sheep rearing, therefore, the bioavailable fraction of some selected heavy metals namely (Cu, Pb, Zn, Mn, Cr, Ni, and V) has been evaluated using 0.01 M EDTA procedure, as this would help for better understanding of the risk that these heavy metals can pose to living organisms. A total of 51 samples of topsoils, floodplain soils, and stream sediment soils were collected and analysed for their total concentrations using ICP (Inductively Coupled Plasma) optical emission spectroscopy. Results show that, depending on the bioavailable ratio, soil samples have the biggest EDTA extractable amount for all studied metals, except for Mn and Cr for which highest levels were found in the floodplain samples. However, based on national bioavailable mean amount in England and Wales, the amount of EDTA metal extractable for all selected metals from soil samples are exceeded the national average amounts of England and Wales, except for Mn and Ni, whereas in floodplain and stream sediment samples, all EDTA metals extractions are lower than the national mean levels, except Cu and Zn for flood plan samples. Principal component analysis (PCA) technique was performed to investigate how the bioavailable fractions of studied metals and factors namely (organic matter contents, soil pH, and different granulometric ranges) are correlated. Results show that both organic matter amounts and fine fractions (clay and silt) were the master factors controlling the bioavailable portion in all soil types
A Dependence of the Tidal Disruption Event Rate on Global Stellar Surface Mass Density and Stellar Velocity Dispersion
© 2018. The American Astronomical Society. All rights reserved. The rate of tidal disruption events (TDEs), R TDE , is predicted to depend on stellar conditions near the super-massive black hole (SMBH), which are on difficult-to-measure sub-parsec scales. We test whether R TDE depends on kpcscale global galaxy properties, which are observable. We concentrate on stellar surface mass density, ∑ M∗ , and velocity dispersion, σ v , which correlate with the stellar density and velocity dispersion of the stars around the SMBH. We consider 35 TDE candidates, with and without known X-ray emission. The hosts range from starforming to quiescent to quiescent with strong Balmer absorption lines. The last (often with post-starburst spectra) are overrepresented in our sample by a factor of 35 +21 -17 or 18 +8 -7 , depending on the strength of the Hδ absorption line. For a subsample of hosts with homogeneous measurements, ∑ M∗ = 10 9 -10 10 M ⊙ /kpc 2 , higher on average than for a volume-weighted control sample of Sloan Digital Sky Survey galaxies with similar redshifts and stellar masses. This is because (1) most of the TDE hosts here are quiescent galaxies, which tend to have higher ∑ M∗ than the star-forming galaxies that dominate the control, and (2) the star-forming hosts have higher average ∑ M∗ than the star-forming control. There is also a weak suggestion that TDE hosts have lower σ v than for the quiescent control. Assuming that R TDE ∝ ∑ M∗ α × σ v β , and applying a statistical model to the TDE hosts and control sample, we estimate α = 0.9 ; 0.2 and β = -1.0 0.6. This is broadly consistent with RTDE being tied to the dynamical relaxation of stars surrounding the SMBH
Effectiveness of the BNT162b2 (Pfizer-BioNTech) Vaccine in Children and Adolescents: A Systematic Review and Meta-Analysis
Efforts to control the COVID-19 pandemic have expanded to the vaccination of children and
adolescents. This systematic review assesses the utility of the BNT162b2 (Pfizer-BioNTech) vaccine
in children and adolescents aged 5–18 years, considering its effectiveness against COVID infection,
hospital and intensive care admission and duration of effectiveness after vaccination. Six databases
were searched following the PRISMA guidelines. Pooled estimates and 95% confidence intervals
(CIs) were calculated using meta-analysis. Fifteen studies were included in the systematic review,
while 12 studies were included in the meta-analysis. Evidence suggests that the two-dose vaccination
regime provided high effectiveness of 92% (95% CI, 86–96) against COVID infection. Vaccination
also conferred high protection against hospitalisation (91%) and intensive care admission (85%). The
vaccine was highly protective against the Delta variant of the virus, but showed a lower protection
against the Omicron variant. Most adverse effects were transient and mild, commonly including pain
at the injection site, fatigue and headache. Current findings are suggestive of waning immunity over
time; however, further research is needed to investigate the relevance of booster doses in this age
group. In summary, the Pfizer-BioNTech BNT162b2 vaccine demonstrated high levels of protection
against COVID-19 infection and its complications while maintaining an adequate safety profile in
children and adolescents
The combined effect of biological control with plant competition on the management of parthenium weed (Parthenium hysterophorus L.)
Parthenium hysterophorus L., (Asteraceae) commonly known as parthenium weed, is a highly invasive plant that has become a problematic weed of pasture lands in Australia and many other countries around the world. For the management of this weed, an integrated approach comprising biological control and plant competition strategies was tested in southern central Queensland. Two competitive pasture plant species (butterfly pea and buffel grass), selected for their high competitive ability, worked successfully with the biological control agent (Epiblema strenuana Walker) to synergistically reduce the biomass of parthenium weed, by between 62 and 69%. In the presence of biological control agent, the corresponding biomass of competitive plants, butterfly pea and buffel grass increased in comparison to when the biological control agent had been excluded, by 15 and 35%, respectively. This suggests that biological control and competitive plants can complement one another to bring about improved management of parthenium weed in Australia. Further, this approach may be adopted in countries where some of the biological control agents are already present including South Africa, Ethiopia, India, Pakistan and Nepal
The FMOS-COSMOS survey of star-forming galaxies at z~1.6. IV: Excitation state and chemical enrichment of the interstellar medium
We investigate the physical conditions of ionized gas in high-z star-forming
galaxies using diagnostic diagrams based on the rest-frame optical emission
lines. The sample consists of 701 galaxies with an Ha detection at , from the FMOS-COSMOS survey, that represent the normal
star-forming population over the stellar mass range with those at being
well sampled. We confirm an offset of the average location of star-forming
galaxies in the BPT diagram ([OIII]/Hb vs. [NII]/Ha), primarily towards higher
[OIII]/Hb, compared with local galaxies. Based on the [SII] ratio, we measure
an electron density (), that is higher
than that of local galaxies. Based on comparisons to theoretical models, we
argue that changes in emission-line ratios, including the offset in the BPT
diagram, are caused by a higher ionization parameter both at fixed stellar mass
and at fixed metallicity with additional contributions from a higher gas
density and possibly a hardening of the ionizing radiation field. Ionization
due to AGNs is ruled out as assessed with Chandra. As a consequence, we revisit
the mass-metallicity relation using [NII]/Ha and a new calibration including
[NII]/[SII] as recently introduced by Dopita et al. Consistent with our
previous results, the most massive galaxies ()
are fully enriched, while those at lower masses have metallicities lower than
local galaxies. Finally, we demonstrate that the stellar masses, metallicities
and star formation rates of the FMOS sample are well fit with a
physically-motivated model for the chemical evolution of star-forming galaxies.Comment: 38 pages; Accepted for publication in Ap
Efficient synthesis of novel benzo[b][1,8]naphthyridin-4(1H)-ones and pyrido[2,3-b]quinoxalin-4(1H)-ones from alkynones and primary amines
An efficient palladium-catalyzed cyclization of o-chlorohetaryl ynones with aliphatic and aromatic primary amines represents a simple access to a wide range of benzo[b][1,8]naphthyridin-4(1H)-one and pyrido[2,3-b]quinoxalin-4(1H)- one derivatives in good to excellent yields. © 2013 Elsevier Ltd. All rights reserved
The FMOS-COSMOS survey of star-forming galaxies at z ~ 1.6. I. H\alpha -based star formation rates and dust extinction
We present the first results from a near-IR spectroscopic survey of the
COSMOS field, using the Fiber Multi-Object Spectrograph on the Subaru
telescope, designed to characterize the star-forming galaxy population at
. The high-resolution mode is implemented to detect H in
emission between with erg cm s. Here, we specifically
focus on 271 sBzK-selected galaxies that yield a H detection thus
providing a redshift and emission line luminosity to establish the relation
between star formation rate and stellar mass. With further -band
spectroscopy for 89 of these, the level of dust extinction is assessed by
measuring the Balmer decrement using co-added spectra. We find that the
extinction () rises with stellar
mass and is elevated at high masses compared to low-redshift galaxies. Using
this subset of the spectroscopic sample, we further find that the differential
extinction between stellar and nebular emission
\hbox{} is 0.7--0.8, dissimilar to
that typically seen at low redshift. After correcting for extinction, we derive
an H-based main sequence with a slope () and normalization
similar to previous studies at these redshifts.Comment: 6 pages, 4 figures, and 1 table. Published in ApJ Letter
The FMOS-COSMOS survey of star-forming galaxies at z~1.6 III. Survey design, performance, and sample characteristics
We present a spectroscopic survey of galaxies in the COSMOS field using the
Fiber Multi-Object Spectrograph (FMOS), a near-infrared instrument on the
Subaru Telescope. Our survey is specifically designed to detect the Halpha
emission line that falls within the H-band (1.6-1.8 um) spectroscopic window
from star-forming galaxies with 1.4 ~10^10 Msolar. With
the high multiplex capability of FMOS, it is now feasible to construct samples
of over one thousand galaxies having spectroscopic redshifts at epochs that
were previously challenging. The high-resolution mode (R~2600) effectively
separates Halpha and [NII]6585 thus enabling studies of the gas-phase
metallicity and photoionization state of the interstellar medium. The primary
aim of our program is to establish how star formation depends on stellar mass
and environment, both recognized as drivers of galaxy evolution at lower
redshifts. In addition to the main galaxy sample, our target selection places
priority on those detected in the far-infrared by Herschel/PACS to assess the
level of obscured star formation and investigate, in detail, outliers from the
star formation rate - stellar mass relation. Galaxies with Halpha detections
are followed up with FMOS observations at shorter wavelengths using the J-long
(1.11-1.35 um) grating to detect Hbeta and [OIII]5008 that provides an
assessment of extinction required to measure star formation rates not hampered
by dust, and an indication of embedded Active Galactic Nuclei. With 460
redshifts measured from 1153 spectra, we assess the performance of the
instrument with respect to achieving our goals, discuss inherent biases in the
sample, and detail the emission-line properties. Our higher-level data
products, including catalogs and spectra, are available to the community.Comment: 26 pages, Updated version resubmitted to ApJSS; Data products and
catalogs are now available at http://member.ipmu.jp/fmos-cosmos
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