1,230 research outputs found
Glycosaminoglycans and Glycosaminoglycan Mimetics in Cancer and Inflammation
Glycosaminoglycans (GAGs) are a class of biomolecules expressed virtually on all mammalian cells and usually covalently attached to proteins, forming proteoglycans. They are present not only on the cell surface, but also in the intracellular milieu and extracellular matrix. GAGs interact with multiple ligands, both soluble and insoluble, and modulate an important role in various physiological and pathological processes including cancer, bacterial and viral infections, inflammation, Alzheimer’s disease, and many more. Considering their involvement in multiple diseases, their use in the development of drugs has been of significant interest in both academia and industry. Many GAG-based drugs are being developed with encouraging results in animal models and clinical trials, showcasing their potential for development as therapeutics. In this review, the role GAGs play in both the development and inhibition of cancer and inflammation is presented. Further, advancements in the development of GAGs and their mimetics as anti-cancer and anti-inflammatory agents are discussed
The influence of noise sources on cross-correlation amplitudes
We use analytical examples and asymptotic forms to examine the mathematical
structure and physical meaning of the seismic cross correlation measurement. We
show that in general, cross correlations are not Green's functions of medium,
and may be very different depending on the source distribution. The modeling of
noise sources using spatial distributions as opposed to discrete collections of
sources is emphasized. When stations are illuminated by spatially complex
source distributions, cross correlations show arrivals at a variety of time
lags, from zero to the maximum surface-wave arrival time. Here, we demonstrate
the possibility of inverting for the source distribution using the energy of
the full cross-correlation waveform. The interplay between the source
distribution and wave attenuation in determining the functional dependence of
cross correlation energies on station-pair distance is quantified. Without
question, energies contain information about wave attenuation. However, the
accurate interpretation of such measurements is tightly connected to the
knowledge of the source distribution.Comment: 19 pages, 17 figures; Geophysical Journal Internationa
Measurements and Kernels for Source-Structure Inversions in Noise Tomography
Seismic noise cross correlations are used to image crustal structure and
heterogeneity. Typically, seismic networks are only anisotropically illuminated
by seismic noise, a consequence of the non-uniform distribution of sources.
Here, we study the sensitivity of such a seismic network to structural
heterogeneity in a 2-D setting. We compute finite-frequency cross-correlation
sensitivity kernels for travel-time, waveform-energy and waveform-difference
measurements. In line with expectation, wavespeed anomalies are best imaged
using travel times and the source distribution using cross-correlation
energies. Perturbations in attenuation and impedance are very difficult to
image and reliable inferences require a high degree of certainty in the
knowledge of the source distribution and wavespeed model (at least in the case
of transmission tomography studied here). We perform single-step Gauss-Newton
inversions for the source distribution and the wavespeed, in that order, and
quantify the associated Cram\'{e}r-Rao lower bound. The inversion and
uncertainty estimate are robust to errors in the source model but are sensitive
to the theory used to interpret of measurements. We find that when classical
source-receiver kernels are used instead of cross-correlation kernels, errors
appear in the both the inversion and uncertainty estimate, systematically
biasing the results. We outline a computationally tractable algorithm to
account for distant sources when performing inversions.Comment: 19 pages, 12 figures, Geophysical Journal Internationa
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