University of North Carolina at Charlotte

About: University of North Carolina at Charlotte is a education organization based out in Charlotte, North Carolina, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 8772 authors who have published 22239 publications receiving 562529 citations. The organization is also known as: UNC Charlotte & UNCC.

Optical dielectric function of silver

Abstract: Using broadband spectroscopic ellipsometry, the authors determine the complex valued dielectric function of silver films from 0.05 eV (\ensuremath{\lambda}=25 \ensuremath{\mu}) to 4.14 eV (\ensuremath{\lambda} = 300 nm) with a statistical uncertainty of less than 1%. While several previous similar measurements exist, they span considerably shorter energy ranges and report partially inconsistent results. In view of the wide-ranging applications of silver in nanophotonics, plasmonics and optical metamaterials, we anticipate this paper to become a standard reference for many scientists and engineers.

Cultured astrocytes express toll‐like receptors for bacterial products

Abstract: It has become apparent that astrocytes may be important contributors to inflammatory immune responses within the brain in response to microbial challenges. To date, the mechanisms that underlie activation of this major glial cell type by such challenges have not been investigated. In the present study, we present evidence for members of a recently discovered family of receptors for highly conserved microbial components, the Toll-like receptors (TLRs), in isolated cultures of primary murine astrocytes. We describe the low-level constitutive expression of messenger RNA-encoding TLR2, TLR4, TLR5, and TLR9 in resting cultures of these cells. Importantly, the level of expression of messenger RNA for each of these receptors is markedly elevated following exposure to specific bacteria-derived ligands for these receptors. The functional expression of these receptor proteins is further supported by the ability of known ligands for each TLR to induce both message expression and protein secretion of the proinflammatory cytokine, interleukin-6. In addition, the recent availability of antibodies to TLR2 and TLR4 has enabled us to demonstrate directly the presence of these receptors on astrocytes by Western blot and immunofluorescence analysis, respectively. Furthermore, we have confirmed the sensitivity of such receptor expression to ligand stimulation. The present demonstration of Toll-like microbial pattern-recognition receptors on primary astrocytes provides a mechanistic link between bacterial challenge and inflammatory immune responses that may be an important component of the pathologies of bacterially induced inflammatory CNS disorders.

Impact of Ocean Acidification on Energy Metabolism of Oyster, Crassostrea gigas—Changes in Metabolic Pathways and Thermal Response

Abstract: Climate change with increasing temperature and ocean acidification (OA) poses risks for marine ecosystems. According to Portner and Farrell [1], synergistic effects of elevated temperature and CO(2)-induced OA on energy metabolism will narrow the thermal tolerance window of marine ectothermal animals. To test this hypothesis, we investigated the effect of an acute temperature rise on energy metabolism of the oyster, Crassostrea gigas chronically exposed to elevated CO(2) levels (partial pressure of CO(2) in the seawater similar to 0.15 kPa, seawater pH similar to 7.7). Within one month of incubation at elevated PCO(2) and 15 degrees C hemolymph pH fell (pH(e) = 7.1 +/- 0.2 (CO(2)-group) vs. 7.6 +/- 0.1 (control)) and P(e)CO(2) values in hemolymph increased (0.5 +/- 0.2 kPa (CO(2)-group) vs. 0.2 +/- 0.04 kPa (control)). Slightly but significantly elevated bicarbonate concentrations in the hemolymph of CO(2)-incubated oysters ([HCO(3)(-)](e) = 1.8 +/- 0.3 mM (CO(2)-group) vs. 1.3 +/- 0.1 mM (control)) indicate only minimal regulation of extracellular acid-base status. At the acclimation temperature of 15 degrees C the OA-induced decrease in pHe did not lead to metabolic depression in oysters as standard metabolism rates (SMR) of CO(2)-exposed oysters were similar to controls. Upon acute warming SMR rose in both groups, but displayed a stronger increase in the CO(2)-incubated group. Investigation in isolated gill cells revealed a similar temperature-dependence of respiration between groups. Furthermore, the fraction of cellular energy demand for ion regulation via Na(+)/K(+)-ATPase was not affected by chronic hypercapnia or temperature. Metabolic profiling using (1)H-NMR spectroscopy revealed substantial changes in some tissues following OA exposure at 15 degrees C. In mantle tissue alanine and ATP levels decreased significantly whereas an increase in succinate levels was observed in gill tissue. These findings suggest shifts in metabolic pathways following OA-exposure. Our study confirms that OA affects energy metabolism in oysters and suggests that climate change may affect populations of sessile coastal invertebrates such as mollusks.

Personality moderators of the relationship between abusive supervision and subordinates' resistance.

Abstract: Results of a study using data collected at 2 points in time, separated by 6 months, suggested that subordinates resisted their supervisors' downward influence tactics with greater frequency when their supervisors were more abusive and that subordinates' personality moderated the effects of abusive supervision. The relationship between abusive supervision and subordinates' dysfunctional resistance was stronger among subordinates who were lower in conscientiousness than among subordinates who were higher in conscientiousness, but this effect emerged only for subordinates who were also lower in agreeableness. The relationship between abusive supervision and subordinates' constructive resistance was stronger among subordinates who were higher in conscientiousness than among subordinates who were lower in conscientiousness. The study's implications for theory and research are discussed.

A 3D human triculture system modeling neurodegeneration and neuroinflammation in Alzheimer's disease.

Abstract: Alzheimer's disease (AD) is characterized by beta-amyloid accumulation, phosphorylated tau formation, hyperactivation of glial cells, and neuronal loss. The mechanisms of AD pathogenesis, however, remain poorly understood, partially due to the lack of relevant models that can comprehensively recapitulate multistage intercellular interactions in human AD brains. Here we present a new three-dimensional (3D) human AD triculture model using neurons, astrocytes, and microglia in a 3D microfluidic platform. Our model provided key representative AD features: beta-amyloid aggregation, phosphorylated tau accumulation, and neuroinflammatory activity. In particular, the model mirrored microglial recruitment, neurotoxic activities such as axonal cleavage, and NO release damaging AD neurons and astrocytes. Our model will serve to facilitate the development of more precise human brain models for basic mechanistic studies in neural-glial interactions and drug discovery.