298 research outputs found
Zinc released from olfactory bulb glomeruli by patterned electrical stimulation of the olfactory nerve
Zinc is a trace element with a multitude of roles in biological systems including structural and cofactor functions for proteins. Although most zinc in the central nervous system (CNS) is protein bound, the CNS contains a pool of mobile zinc housed in synaptic vesicles within a subset of neurons. Such mobile zinc occurs in many brain regions, such as the hippocampus, hypothalamus, and cortex, but the olfactory bulb (OB) contains one of the highest such concentrations in the CNS. Zinc is distributed throughout the OB, with the glomerular and granule cell layers containing the highest levels. Here, we visualize vesicular zinc in the OB using zinc-responsive fluorescent probes developed by one of us. Moreover, we provide the first demonstration that vesicular pools of zinc can be released from olfactory nerve terminals within individual glomeruli by patterned electrical stimulation of the olfactory nerve designed to mimic the breathing cycle in rats. We also provide electrophysiological evidence that elevated extracellular zinc potentiates α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor-mediated synaptic events. AMPA receptors are required for the synchronous activation of neurons within individual OB glomeruli, and zinc-mediated potentiation leads to enhanced synaptic summation.National Institute of General Medical Sciences (U.S.) (Grant GM065519)Florida State University. Program in Neuroscience (Council on Research and Creativity
Examining the effect of health behaviors on wages and healthcare utilization in models with endogeneity
This dissertation contains three essays on applied health economics. Although each essay is independent of the others, all three address the issue of estimating models where the relationship of interest is confounded by factors that are unobservable to the researcher. The first essay is an econometric simulation study while essays 2 and 3 address behavioral health topics. Essay 1 compares the accuracy and efficiency of parametric count data specifications paired with the Extended Olsen Model (EOM; Terza, 1998, 2009). The EOM is a nonlinear instrumental variables approach that allows for consistent estimation of model parameters when the data suffer from binary endogenous switching (e.g., endogenous sample selection or endogenous treatment). Count data models are ubiquitous in the health literature for estimating non-negative, discrete outcomes such as physician visits, hospital admissions, cigarettes smoked, etc. Essay 1 provides insight into the model selection process by informing practitioners which specification is likely to provide the most accurate parameter estimates under a variety of data configurations. Essay 1 also demonstrates the applicability of the Conway-Maxwell Poisson (CMP), a flexible count model developed in the field of industrial engineering that has yet to be utilized in the economic literature. In Essay 2 I apply a count version of the Extended Olsen Model to estimate the relationship between marijuana use disorder (MUD) and ER visits among US Medicaid recipients. This essay is the first in the literature to estimate the relationship between marijuana consumption and the demand for ER visits in isolation from other illicit drugs, thus providing an important addition to the ongoing policy regarding the potential relaxation of marijuana regulation. This study is also the first in the illicit substance literature to use an instrumental variables count data model to estimate the full distribution of ER visits, thus accounting for unobserved factors that may be jointly correlated between individual propensity for MUD and demand for ER visits. I fail to find a positive relationship between MUD and ER visits, instead uncovering suggestive, but inconclusive, evidence that MUD and ER visits may rather be negatively correlated. Essay 3 considers the relationship between wages and obesity. Although prior literature has firmly established a negative relationship between wages and obesity, it is equivocal with regard to the underlying pathway(s) through which obesity results in lower wages. Using firm-level data that gives me unique access to proxies for productivity and discrimination against obese individuals, I find that inputs to productivity, particularly health, are important confounders of the wage-obesity relationship. I fail to find any evidence of discrimination against obese employees, but I do find that among females the negative relationship between wages and obesity exists only among mothers
Massive Stars In The W33 Giant Molecular Complex
Rich in H II regions, giant molecular clouds are natural laboratories to study massive stars and sequential star formation. The Galactic star-forming complex W33 is located at = ∼ ◦ l 12.8 and at a distance of 2.4 kpc and has a size of ≈10 pc and a total mass of ≈(0.8−8.0) × 105 M⊙. The integrated radio and IR luminosity of W33—when combined with the direct detection of methanol masers, the protostellar object W33A, and the protocluster embedded within the radio source W33 main—mark the region as a site of vigorous ongoing star formation. In order to assess the long-term star formation history, we performed an infrared spectroscopic search for massive stars, detecting for the first time 14 early-type stars, including one WN6 star and four O4–7 stars. The distribution of spectral types suggests that this population formed during the past ∼2–4 Myr, while the absence of red supergiants precludes extensive star formation at ages 6–30 Myr. This activity appears distributed throughout the region and does not appear to
have yielded the dense stellar clusters that characterize other star-forming complexes such as Carina and G305. Instead, we anticipate that W33 will eventually evolve into a loose stellar aggregate, with Cyg OB2 serving as a useful, albeit richer and more massive, comparator. Given recent distance estimates, and despite a remarkably similar stellar population, the rich cluster Cl 1813–178 located on the northwest edge of W33 does not appear to be physically associated with W33
Glucose effects on gastric motility and tone evoked from the rat dorsal vagal complex
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66102/1/j.1469-7793.2001.t01-1-00141.x.pd
Massive stars in the giant molecular cloud G23.3−0.3 and W41
Context. Young massive stars and stellar clusters continuously form in the Galactic disk, generating new Hii regions within their natal giant molecular clouds and subsequently enriching the interstellar medium via their winds and supernovae.Aims. Massive stars are among the brightest infrared stars in such regions; their identification permits the characterisation of the star formation history of the associated cloud as well as constraining the location of stellar aggregates and hence their occurrence as a function of global environment.Methods. We present a stellar spectroscopic survey in the direction of the giant molecular cloud G23.3−0.3. This complex is located at a distance of ~4–5 kpc, and consists of several Hii regions and supernova remnants.Results. We discovered 11 OfK+ stars, one candidate luminous blue variable, several OB stars, and candidate red supergiants. Stars with K-band extinction from ~1.3–1.9 mag appear to be associated with the GMC G23.3−0.3; O and B-types satisfying this criterion have spectrophotometric distances consistent with that of the giant molecular cloud. Combining near-IR spectroscopic and photometric data allowed us to characterize the multiple sites of star formation within it. The O-type stars have masses from ~25–45 M⊙, and ages of 5–8 Myr. Two new red supergiants were detected with interstellar extinction typical of the cloud; along with the two RSGs within the cluster GLIMPSE9, they trace an older burst with an age of 20–30 Myr. Massive stars were also detected in the core of three supernova remnants – W41, G22.7−0.2, and G22.7583−0.4917.Conclusions. A large population of massive stars appears associated with the GMC G23.3−0.3, with the properties inferred for them indicative of an extended history of stars formation
Characteristics of Abnormal Diffusivity in Normal-Appearing White Matter Investigated with Diffusion Tensor MR Imaging in Tuberous Sclerosis Complex
The current landscape of nucleic acid tests for filovirus detection.
Nucleic acid testing (NAT) for pathogenic filoviruses plays a key role in surveillance and to control the spread of infection. As they share clinical features with other pathogens, the initial spread of these viruses can be misdiagnosed. Tests that can identify a pathogen in the initial stages of infection are essential to control outbreaks. Since the Ebola virus disease (EVD) outbreak in 2014-2016 several tests have been developed that are faster than previous tests and more suited for field use. Furthermore, the ability to test for a range of pathogens simultaneously has been expanded to improve clinical pathway management of febrile syndromes. This review provides an overview of these novel diagnostic tests
Elucidation of the ebola virus VP24 cellular interactome and disruption of virus biology through targeted inhibition of host-cell protein function
Viral pathogenesis in the infected cell is a balance between antiviral responses and subversion of host-cell processes. Many viral proteins specifically interact with host-cell proteins to promote virus biology. Understanding these interactions can lead to knowledge gains about infection and provide potential targets for antiviral therapy. One such virus is Ebola, which has profound consequences for human health and causes viral hemorrhagic fever where case fatality rates can approach 90%. The Ebola virus VP24 protein plays a critical role in the evasion of the host immune response and is likely to interact with multiple cellular proteins. To map these interactions and better understand the potential functions of VP24, label-free quantitative proteomics was used to identify cellular proteins that had a high probability of forming the VP24 cellular interactome. Several known interactions were confirmed, thus placing confidence in the technique, but new interactions were also discovered including one with ATP1A1, which is involved in osmoregulation and cell signaling. Disrupting the activity of ATP1A1 in Ebola-virus-infected cells with a small molecule inhibitor resulted in a decrease in progeny virus, thus illustrating how quantitative proteomics can be used to identify potential therapeutic targets
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