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Magnetic Resonance Spectroscopy of the Brain in Alcohol Abuse.
Magnetic resonance (MR) technology produces data on brain structure and activity without relying on radiation or invasive surgery. Magnetic resonance imaging (MRI) creates images, and magnetic resonance spectroscopy (MRS) produces spectra based on the ability of atomic nuclei in tissues to absorb and release pulses of energy. MRS studies of alcohol in the brain reveal that only a portion of the alcohol in the brain can be detected by MR technology, suggesting that alcohol there exists in multiple pools. The pools not visible using MRS is hypothesized to be bound to cell membranes. Indirect evidence from MR studies of chronic alcohol abusers suggests that tolerance to alcohol's effects results in an increased rigidity of cell membranes that forces more alcohol to remain in the MR-visible pool (i.e., the pool not bound to membranes) compared with alcohol in the brains of nontolerant people
Time-dependent heterogeneity leads to transient suppression of the COVID-19 epidemic, not herd immunity
Epidemics generally spread through a succession of waves that reflect factors
on multiple timescales. On short timescales, super-spreading events lead to
burstiness and overdispersion, while long-term persistent heterogeneity in
susceptibility is expected to lead to a reduction in the infection peak and the
herd immunity threshold (HIT). Here, we develop a general approach to encompass
both timescales, including time variations in individual social activity, and
demonstrate how to incorporate them phenomenologically into a wide class of
epidemiological models through parameterization. We derive a non-linear
dependence of the effective reproduction number Re on the susceptible
population fraction S. We show that a state of transient collective immunity
(TCI) emerges well below the HIT during early, high-paced stages of the
epidemic. However, this is a fragile state that wanes over time due to changing
levels of social activity, and so the infection peak is not an indication of
herd immunity: subsequent waves can and will emerge due to behavioral changes
in the population, driven (e.g.) by seasonal factors. Transient and long-term
levels of heterogeneity are estimated by using empirical data from the COVID-19
epidemic as well as from real-life face-to-face contact networks. These results
suggest that the hardest-hit areas, such as NYC, have achieved TCI following
the first wave of the epidemic, but likely remain below the long-term HIT.
Thus, in contrast to some previous claims, these regions can still experience
subsequent waves
Optimized loading of an optical dipole trap for the production of Chromium BECs
We report on a strategy to maximize the number of chromium atoms transferred
from a magneto-optical trap into an optical trap through accumulation in
metastable states via strong optical pumping. We analyse how the number of
atoms in a chromium Bose Einstein condensate can be raised by a proper handling
of the metastable state populations. Four laser diodes have been implemented to
address the four levels that are populated during the MOT phase. The individual
importance of each state is specified. To stabilize two of our laser diode, we
have developed a simple ultrastable passive reference cavity whose long term
stability is better than 1 MHz
A Biometric Model for Mineralization of Type-I Collagen Fibrils
The bone and dentin mainly consist of type-I collagen fibrils mineralized by hydroxyapatite (HAP) nanocrystals. In vitro biomimetic models based on self-assembled collagen fibrils have been widely used in studying the mineralization mechanism of type-I collagen. In this chapter, the protocol we used to build a biomimetic model for the mechanistic study of type-I collagen mineralization is described. Type-I collagen extracted from rat tail tendon or horse tendon is self-assembled into fibrils and mineralized by HAP in vitro. The mineralization process is monitored by cryoTEM in combination with two-dimensional (2D) and three-dimensional (3D) stochastic optical reconstruction microscopy (STORM), which enables in situ and high-resolution visualization of the process
Characterization of AGN and their hosts in the Extended Groth Strip: a multiwavelength analysis
We have employed a reliable technique of classification of Active Galactic
Nuclei (AGN) based on the fit of well-sampled spectral energy distributions
(SEDs) with a complete set of AGN and starburst galaxy templates. We have
compiled ultraviolet, optical, and infrared data for a sample of 116 AGN
originally selected for their X-ray and mid-infrared emissions (96 with single
detections and 20 with double optical counterparts). This is the most complete
compilation of multiwavelength data for such a big sample of AGN in the
Extended Groth Strip (EGS). Through these SEDs, we are able to obtain highly
reliable photometric redshifts and to distinguish between pure and
host-dominated AGN. For the objects with unique detection we find that they can
be separated into five main groups, namely: Starburst-dominated AGN (24 % of
the sample), Starburst-contaminated AGN (7 %), Type-1 AGN (21 %), Type-2 AGN
(24 %), and Normal galaxy hosting AGN (24 %). We find these groups concentrated
at different redshifts: Type-2 AGN and Normal galaxy hosting AGN are
concentrated at low redshifts, whereas Starburst-dominated AGN and Type-1 AGN
show a larger span. Correlations between hard/soft X-ray and ultraviolet,
optical and infrared luminosities, respectively, are reported for the first
time for such a sample of AGN spanning a wide range of redshifts. For the 20
objects with double detection the percentage of Starburst-dominated AGN
increases up to 48%.Comment: 38 pages, 8 figures, 5 tables. Accepted by A
Essential Components of Cancer Education
Modern cancer therapy/care involves the integration of basic, clinical, and population-based research professionals using state-of-the-art science to achieve the best possible patient outcomes. A well-integrated team of basic, clinical, and population science professionals and educators working with a fully engaged group of creative junior investigators and trainees provides a structure to achieve these common goals. To this end, the structure provided by cancer-focused educational programs can create the integrated culture of academic medicine needed to reduce the burden of cancer on society. This summary outlines fundamental principles and potential best practice strategies for the development of integrated educational programs directed at achieving a work force of professionals that broadly appreciate the principals of academic medicine spanning the breadth of knowledge necessary to advance the goal of improving the current practice of cancer care medicine
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