Study of a High-Power, Pulsed Plasma Jet with a Heterodyne Interferometer

Presented is a method to measure the line-averaged electron density and velocity of a plasma jet generated by a pulsed plasma source, using a heterodyne interferometer. This source will produce a plasma jet that exhibits instabilities and magnetic reconnection [1] inside Embry-Riddle’s two meter long, cylindrical plasma chamber. Magnetic reconnection is a process by which a portion of magnetic field energy is transferred into kinetic or thermal energy of plasma [1]. A heterodyne interferometer is similar to a Michelson interferometer, with the difference that the non-plasma beam is passed through an acoustic-optical modulator that isolates the 1st harmonic of the beam. The Interferometer measures the change in the index of refraction of the plasma chamber, this enables the determination of the change of the line-averaged electron density of the plasma jet. By interpreting this data over system parameter variations, changes in the density of the plasma jet over the course of the experiment will be studied. This study will investigate fundamental plasma physics and applications, such as the drivers and patterns of reconnection and may lead to improved fusion energy generation and pulsed plasma propulsion. References: [1] Seo, B., Wongwaitayakornkul, P., Haw, Magnus. A., Marshall, Ryan S., Li, Hui, and Bellan, Paul (2020) Determination of macro to microscale progression leading to a magnetized plasma disruption, Physics of plasmas, 27, 02210

Study of a High-Power, Pulsed Plasma Jet with a Heterodyne Interferometer

Presented is a method to measure the line-averaged electron density and velocity of a plasma jet generated by a pulsed plasma source, using a heterodyne interferometer. This source will produce a plasma jet that exhibits instabilities and magnetic reconnection inside Embry-Riddle’s two meter long, cylindrical plasma chamber. A heterodyne interferometer is similar to a Michelson interferometer, with the difference that the non-plasma beam is passed through an acoustic-optical modulator that isolates the 1st harmonic of the beam. A fiber optic cable is used to transmit the scene beam to the vacuum chamber from the optics bench and back, allowing easy variation to sampling location across experiments. The Interferometer measures the change in the index of refraction of the plasma chamber, this enables the determination of the change of the line-averaged electron density of the plasma jet. Preliminary data has measured jet velocities of ~9.1 km/s and maximum line-averaged number densities of 2.09*1021 (1/m-3). By interpreting this data over system parameter variations, changes in the density of the plasma jet over the course of the experiment will be studied. This study will investigate fundamental plasma physics and applications, such as the drivers and patterns of reconnection

Potable Water For a Volcanic Community In Rural Guatemala

The project, in partnership with Santa Clara University Frugal Innovation Hub and Instituto de Investigacion y Proyeccion sobre Ciencia y Tecnologia (INCYT) at Universidad Rafael Landivar, aimed to provide Panimache II, a small volcanic Guatemalan community, with access to clean and affordable water. The team designed a water treatment plant and distribution system, consisting of a hydraulic flocculator, sedimentation basin, slow-sand filter, and chlorination chamber, to remove the high levels of ash and other suspended solids. Components of the project included analyzing water source and quality, availability of construction materials, and recommended construction to effectively design and implement the community\u27s water treatment and distribution system. Due to restrictions caused by the COVID-19 pandemic, this project was theoretical and will only be considered for implementation when conditions permit

Shear and Bearing Capacity of Corroded Steel Beam Bridges and the Effects on Load Rating

Corrosion in the girders of steel girder bridges often occurs due to the deicing salts, water, and other debris that leak through the deck joints into the web and bottom flange at the girder ends. Corrosion causes loss of cross-sectional area leading to a reduction in section properties of the member, which eventually results in a reduction in structural resistance against shear and bearing. In this study, seven full-scale tests were performed on decommissioned steel girders acquired from bridges scheduled for demolition in Indiana. Two of the four girders had severe corrosion with cracks and holes in the bottom of the web induced by corrosion, while four girders had moderate section loss induced artificially. All seven girders were subjected to shear loading to determine the residual shear and bearing capacity. Test results revealed a reduction in strength due to section loss compared to nominal sections. Failure modes observed during these four large-scale experiments were shear buckling, shear rupture, and web local crippling. Finite element models were developed and benchmarked to the experimental results. Parametric studies were performed for unstiffened and stiffened girders and included different corrosion scenarios by varying parameters such as corrosion height, length, and thickness loss. Results were analyzed to investigate the effect of each parameter and a modification factor was developed to estimate the residual shear and bearing capacity of corroded girders

Protection by Chrysanthemum zawadskii extract from liver damage of mice caused by carbon tetrachloride is maybe mediated by modulation of QR activity

Our previous study demonstrated that methanolic extract of Chrysanthemum zawadskii Herbich var. latilobum Kitamura (Compositae) has the potential to induce detoxifying enzymes such as NAD(P)H:(quinone acceptor) oxidoreductase 1 (EC 1.6.99.2) (NQO1, QR) and glutathione S-transferase (GST). In this study we further fractionated methanolic extract of Chrysanthemum zawadskii and investigated the detoxifying enzyme-inducing potential of each fraction. The fraction (CZ-6) shown the highest QR-inducing activity was found to contain (+)-(3S,4S,5R,8S)-(E)-8-acetoxy-4-hydroxy-3-isovaleroyloxy-2-(hexa-2,4-diynyliden)-1,6-dioxaspiro [4,5] decane and increased QR enzyme activity in a dose-dependent manner. Furthermore, CZ-6 fraction caused a dose-dependent enhancement of luciferase activity in HepG2-C8 cells generated by stably transfecting antioxidant response element-luciferase gene construct, suggesting that it induces antioxidant/detoxifying enzymes through antioxidant response element (ARE)-mediated transcriptional activation of the relevant genes. Although CZ-6 fraction failed to induce hepatic QR in mice over the control, it restored QR activity suppressed by CCl4 treatment to the control level. Hepatic injury induced by CCl4 was also slightly protected by pretreatment with CZ-6. In conclusion, although CZ-6 fractionated from methanolic extract of Chrysanthemum zawadskii did not cause a significant QR induction in mice organs such as liver, kidney, and stomach, it showed protective effect from liver damage caused by CCl4

Chemical composition and antigenotoxic properties of Lippia alba essential oils

The present work evaluated the chemical composition and the DNA protective effect of the essential oils (EOs) from Lippia alba against bleomycin-induced genotoxicity. EO constituents were determined by Gas Chromatography/Mass Spectrometric (GC-MS) analysis. The major compounds encountered being citral (33% geranial and 25% neral), geraniol (7%) and trans-β-caryophyllene (7%) for L. alba specimen COL512077, and carvone (38%), limonene (33%) and bicyclosesquiphellandrene (8%) for the other, COL512078. The genotoxicity and antigenotoxicity of EO and the compounds citral, carvone and limonene, were assayed using the SOS Chromotest in Escherichia coli. The EOs were not genotoxic in the SOS chromotest, but one of the major compound (limonene) showed genotoxicity at doses between 97 and 1549 mM. Both EOs protected bacterial cells against bleomycin-induced genotoxicity. Antigenotoxicity in the two L. alba chemotypes was related to the major compounds, citral and carvone, respectively. The results were discussed in relation to the chemopreventive potential of L. alba EOs and its major compounds

Pyrosequencing of the Camptotheca acuminata transcriptome reveals putative genes involved in camptothecin biosynthesis and transport

Background: Camptotheca acuminata is a Nyssaceae plant, often called the "happy tree", which is indigenous in Southern China. C. acuminata produces the terpenoid indole alkaloid, camptothecin (CPT), which exhibits clinical effects in various cancer treatments. Despite its importance, little is known about the transcriptome of C. acuminata and the mechanism of CPT biosynthesis, as only few nucleotide sequences are included in the GenBank database.Results: From a constructed cDNA library of young C. acuminata leaves, a total of 30,358 unigenes, with an average length of 403 bp, were obtained after assembly of 74,858 high quality reads using GS De Novo assembler software. Through functional annotation, a total of 21,213 unigenes were annotated at least once against the NCBI nucleotide (Nt), non-redundant protein (Nr), Uniprot/SwissProt, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Arabidopsis thaliana proteome (TAIR) databases. Further analysis identified 521 ESTs representing 20 enzyme genes that are involved in the backbone of the CPT biosynthetic pathway in the library. Three putative genes in the upstream pathway, including genes for geraniol-10-hydroxylase (CaPG10H), secologanin synthase (CaPSCS), and strictosidine synthase (CaPSTR) were cloned and analyzed. The expression level of the three genes was also detected using qRT-PCR in C. acuminata. With respect to the branch pathway of CPT synthesis, six cytochrome P450s transcripts were selected as candidate transcripts by detection of transcript expression in different tissues using qRT-PCR. In addition, one glucosidase gene was identified that might participate in CPT biosynthesis. For CPT transport, three of 21 transcripts for multidrug resistance protein (MDR) transporters were also screened from the dataset by their annotation result and gene expression analysis.Conclusion: This study produced a large amount of transcriptome data from C. acuminata by 454 pyrosequencing. According to EST annotation, catalytic features prediction, and expression analysis, novel putative transcripts involved in CPT biosynthesis and transport were discovered in C. acuminata. This study will facilitate further identification of key enzymes and transporter genes in C. acuminata

Study protocol: EXERcise and Cognition In Sedentary adults with Early-ONset dementia (EXERCISE-ON)

<p>Abstract</p> <p>Background</p> <p>Although the development of early-onset dementia is a radical and invalidating experience for both patient and family there are hardly any non-pharmacological studies that focus on this group of patients. One type of a non-pharmacological intervention that appears to have a beneficial effect on cognition in older persons without dementia and older persons at risk for dementia is exercise. In view of their younger age early-onset dementia patients may be well able to participate in an exercise program. The main aim of the EXERCISE-ON study is to assess whether exercise slows down the progressive course of the symptoms of dementia.</p> <p>Methods/Design</p> <p>One hundred and fifty patients with early-onset dementia are recruited. After completion of the baseline measurements, participants living within a 50 kilometre radius to one of the rehabilitation centres are randomly assigned to either an <it>aerobic exercise program in a rehabilitation centre</it> or a <it>flexibility and relaxation program in a rehabilitation centre</it>. Both programs are applied three times a week during 3 months. Participants living outside the 50 kilometre radius are included in a feasibility study where participants join in a <it>daily physical activity program set at home making use of pedometers</it>. Measurements take place at baseline (entry of the study), after three months (end of the exercise program) and after six months (follow-up). Primary outcomes are cognitive functioning; psychomotor speed and executive functioning; (instrumental) activities of daily living, and quality of life. Secondary outcomes include physical, neuropsychological, and rest-activity rhythm measures.</p> <p>Discussion</p> <p>The EXERCISE-ON study is the first study to offer exercise programs to patients with early-onset dementia. We expect this study to supply evidence regarding the effects of exercise on the symptoms of early-onset dementia, influencing quality of life.</p> <p>Trial registration</p> <p>The present study is registered within The Netherlands National Trial Register (ref: NTR2124)</p