Using Two Simulation Tools to Teach Concepts in Introductory Astronomy: A Design-Based Research Approach

Technology in college classrooms has gone from being an enhancement to the learning experience to being something expected by both instructors and students. This design-based research investigation takes technology one step further, putting the tools used to teach directly in the hands of students. The study examined the affordances and constraints of two simulation tools for use in introductory astronomy courses. The variety of experiences participants had using two tools; a virtual reality headset and fulldome immersive planetarium simulation, to manipulate a lunar surface flyby were identified using a multi-method research approach with N = 67 participants. Participants were recruited from classes of students taking astronomy over one academic year at a two-year college. Participants manipulated a lunar flyby using a virtual reality headset and a motion sensor device in the college fulldome planetarium. Data were collected in the form of two post-treatment questionnaires using Likert-type scales and one small group interview. The small group interview was intended to elicit various experiences participants had using the tools. Responses were analyzed quantitatively for optimal flyby speed and qualitatively for salient themes using data reduction informed by a methodological framework of phenomenography to identify the variety of experiences participants had using the tools. Findings for optimal flyby speed of the Moon based on analysis of data for both the Immersion Questionnaire and the Simulator Sickness Questionnaire done using SPSS software determine that the optimal flyby speed for college students to manipulate the Moon was calculated to be .04 x the radius of the Earth (3,959 miles) or 160 miles per second. A variety of different participant experiences were revealed using MAXQDA software to code positive and negative remarks participants had when engaged in the use of each tool. Both tools offer potential to actively engage students with astronomy content in college lecture and laboratory courses

A novel approach to enhancing cellular glutathione levels

20 pages, 9 figures, 1 table.-- PMID: 18702664 [PubMed].-- PMCID: PMC2644427.-- NIHMSID: NIHMS90383.-- Printed version published Nov 2008.Glutathione (GSH) and GSH-associated metabolism provide the major line of defense for the protection of cells from oxidative and other forms of toxic stress. Of the three amino acids that comprise GSH, cysteine is limiting for GSH synthesis. Since extracellularly cysteine is readily oxidized to form cystine, cystine transport mechanisms are essential to provide cells with cysteine. Cystine uptake is mediated by system xc−, a Na+-independent cystine/glutamate antiporter. Inhibition of system xc− by millimolar concentrations of glutamate, a pathway termed oxidative glutamate toxicity, results in GSH depletion and nerve cell death. Recently, we described a series of compounds derived from the conjugation of epicatechin with cysteine and cysteine derivatives that protected nerve cells in culture from oxidative glutamate toxicity by maintaining GSH levels. In this paper, we characterize an additional epicatechin conjugate, cysteamine-epicatechin, that is 5-10 fold more potent than the earlier conjugates. In addition, we show that these epicatechin conjugates maintain GSH levels by enhancing the uptake of cystine into cells through induction of a disulfide exchange reaction, thereby uncoupling the uptake from system xc−. Thus, these novel epicatechin conjugates have the potential to enhance GSH synthesis under a wide variety of forms of toxic stress.Financial support of the NIH (PM) (grant AG025337) and the Spanish Ministry of Education and Science (JLT) (research grants PPQ2003-06602-C04-01 and AGL2006-12210-C03-02/ALI) is acknowledged.Peer reviewe

Fisetin Lowers Methylglyoxal Dependent Protein Glycation and Limits the Complications of Diabetes

The elevated glycation of macromolecules by the reactive dicarbonyl and α-oxoaldehyde methylglyoxal (MG) has been associated with diabetes and its complications. We have identified a rare flavone, fisetin, which increases the level and activity of glyoxalase 1, the enzyme required for the removal of MG, as well as the synthesis of its essential co-factor, glutathione. It is shown that fisetin reduces two major complications of diabetes in Akita mice, a model of type 1 diabetes. Although fisetin had no effect on the elevation of blood sugar, it reduced kidney hypertrophy and albuminuria and maintained normal levels of locomotion in the open field test. This correlated with a reduction in proteins glycated by MG in the blood, kidney and brain of fisetin-treated animals along with an increase in glyoxalase 1 enzyme activity and an elevation in the expression of the rate-limiting enzyme for the synthesis of glutathione, a co-factor for glyoxalase 1. The expression of the receptor for advanced glycation end products (RAGE), serum amyloid A and serum C-reactive protein, markers of protein oxidation, glycation and inflammation, were also increased in diabetic Akita mice and reduced by fisetin. It is concluded that fisetin lowers the elevation of MG-protein glycation that is associated with diabetes and ameliorates multiple complications of the disease. Therefore, fisetin or a synthetic derivative may have potential therapeutic use for the treatment of diabetic complications

A structural comparison of salt forms of dopamine with the structures of other phenylethylamines

The structures of four salt forms of dopamine are reported. These are dopamine [2‐(3,4‐dihydroxyphenyl)ethan‐1‐aminium] benzoate, C8H12NO2+·C7H5O2−, I, dopamine 4‐nitrobenzoate, C8H12NO2+·C7H4NO4−, II, dopamine ethanedisulfonate, 2C8H12NO2+·C2H4O6S22−, III, and dopamine 4‐hydroxybenzenesulfonate monohydrate, C8H12NO2+·C6H5O4S−·H2O, IV. In all four structures, the dopamine cation adopts an extended conformation. Intermolecular interaction motifs that are common in the salt forms of tyramine can be found in related dopamine structures, but hydrogen bonding in the dopamine structures appear to be more variable and less predictable than for tyramine. Packing analysis discovered three dopamine‐containing groups of structures that can be described as isostructural with regards to the cation positions. Two of these groups contain both dopamine and tyramine species, and one of these is also highly variable in other ways too, containing anhydrous and hydrated forms, different anion types and ionized and neutral phenylethylamine species. As such, the group illustrates that packing behaviour can be robust and similar even where intermolecular interactions such as hydrogen bonds are very different

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Effects of dimethyl fumarate on neuroprotection and immunomodulation

BACKGROUND: Neuronal degeneration in multiple sclerosis has been linked to oxidative stress. Dimethyl fumarate is a promising novel oral therapeutic option shown to reduce disease activity and progression in patients with relapsing-remitting multiple sclerosis. These effects are presumed to originate from a combination of immunomodulatory and neuroprotective mechanisms. We aimed to clarify whether neuroprotective concentrations of dimethyl fumarate have immunomodulatory effects. FINDINGS: We determined time- and concentration-dependent effects of dimethyl fumarate and its metabolite monomethyl fumarate on viability in a model of endogenous neuronal oxidative stress and clarified the mechanism of action by quantitating cellular glutathione content and recycling, nuclear translocation of transcription factors, and the expression of antioxidant genes. We compared this with changes in the cytokine profiles released by stimulated splenocytes measured by ELISPOT technology and analyzed the interactions between neuronal and immune cells and neuronal function and viability in cell death assays and multi-electrode arrays. Our observations show that dimethyl fumarate causes short-lived oxidative stress, which leads to increased levels and nuclear localization of the transcription factor nuclear factor erythroid 2-related factor 2 and a subsequent increase in glutathione synthesis and recycling in neuronal cells. Concentrations that were cytoprotective in neuronal cells had no negative effects on viability of splenocytes but suppressed the production of proinflammatory cytokines in cultures from C57BL/6 and SJL mice and had no effects on neuronal activity in multi-electrode arrays. CONCLUSIONS: These results suggest that immunomodulatory concentrations of dimethyl fumarate can reduce oxidative stress without altering neuronal network activity