Implementation of the FAA research and development electromagnetic database

The Idaho National Engineering Laboratory (INEL) has been assisting the FAA in developing a database of information about lightning. The FAA Research and Development Electromagnetic Database (FRED) will ultimately contain data from a variety of airborne and ground-based lightning research projects. An outline of the data currently available in FRED is presented. The data sources which the FAA intends to incorporate into FRED are listed. In addition, it describes how the researchers may access and use the FRED menu system

Comprehensive Analysis of Escape-Cone Losses from Luminescent Waveguides

Luminescent waveguides (LWs) occur in a wide range of applications, from solar concentrators to doped fiber amplifiers. Here we report a comprehensive analysis of escape-cone losses in LWs, which are losses associated with internal rays making an angle less than the critical angle with a waveguide surface. For applications such as luminescent solar concentrators, escape-cone losses often dominate all others. A statistical treatment of escape-cone losses is given accounting for photoselection, photon polarization, and the Fresnel relations, and the model is used to analyze light absorption and propagation in waveguides with isotropic and orientationally aligned luminophores. The results are then compared to experimental measurements performed on a fluorescent dye-doped poly(methyl methacrylate) waveguide

Stable Determination of the Electromagnetic Coefficients by Boundary Measurements

The goal of this paper is to prove a stable determination of the coefficients for the time-harmonic Maxwell equations, in a Lipschitz domain, by boundary measurements

Distribution and abundance of fish and crayfish in a Waikato stream in relation to basin area

The aim of this study was to relate the longitudinal distribution of fish and crayfish to increasing basin area and physical site characteristics in the Mangaotama Stream, Waikato region, North Island, New Zealand. Fish and crayfish were captured with two-pass removal electroshocking at 11 sites located in hill-country with pasture, native forest, and mixed land uses within the 21.6 km2 basin. Number of fish species and lineal biomass of fish increased with increasing basin area, but barriers to upstream fish migration also influenced fish distribution; only climbing and non-migratory species were present above a series of small waterfalls. Fish biomass increased in direct proportion to stream width, suggesting that fish used much of the available channel, and stream width was closely related to basin area. Conversely, the abundance of crayfish was related to the amount of edge habitat, and therefore crayfish did not increase in abundance as basin area increased. Densities of all fish species combined ranged from 17 to 459 fish 100 m-2, and biomass ranged from 14 to 206 g m-2. Eels dominated the fish assemblages, comprising 85-100% of the total biomass; longfinned eels the majority of the biomass at most sites. Despite the open access of the lower sites to introduced brown trout, native species dominated all the fish communities sampled

Hyperglycaemia and lipid differentially impair mouse oocyte developmental competence

Maternal diabetes and obesity are characterised by elevated blood glucose, insulin and lipids, resulting in upregulation of specific fuel-sensing and stress signalling pathways. Previously, we demonstrated that, separately, upregulation of the hexosamine biosynthetic pathway (HBP; under hyperglycaemic conditions) and endoplasmic reticulum (ER) stress (due to hyperlipidaemia) pathways reduce blastocyst development and alter oocyte metabolism. In order to begin to understand how both glucose and lipid metabolic disruptions influence oocyte developmental competence, in the present study we exposed mouse cumulus–oocyte complexes to hyperglycaemia (30 mM) and/or lipid (40 μM) and examined the effects on embryo development. The presence of glucosamine (GlcN; a hyperglycaemic mimetic) or increased lipid during in vitro maturation severely perturbed blastocyst development (P < 0.05). Hyperglycaemia, GlcN and hyperglycaemia + lipid treatments significantly increased HBP activity, increasing total O-linked glycosylation (O-GlcNAcylation) of proteins (P < 0.0001). All treatments also induced ER stress pathways, indicated by the expression of specific ER stress genes. The expression of genes encoding the HBP enzymes glutamine:fructose-6-phosphate amidotransferase 2 (Gfpt2) and O-linked β-N-acetylglucosaminyltransferase (Ogt) was repressed following lipid treatment (P < 0.001). These findings partially implicate the mechanism of O-GlcNAcylation and ER stress as likely contributors to compromised fertility of obese women.Siew L. Wong, Linda L. Wu, Rebecca L. Robker, Jeremy G. Thompson and Melanie L. Sutton McDowal

Alpha-synuclein ferrireductase activity is detectible in vivo, is altered in Parkinson's disease and increases the neurotoxicity of DOPAL

© 2017 Elsevier Inc. The normal cellular role of α-synuclein is of potential importance in understanding diseases in which an aggregated form of the protein has been implicated. A potential loss or change in the normal function of α-synuclein could play a role in the aetiology of diseases such as Parkinson's disease. Recently, it has been suggested that α-synuclein could cause the enzymatic reduction of iron and a cellular increase in Fe(II) levels. Experiments were carried out to determine if such activity could be measured in vivo. Experiments with rats overexpressing human α-synuclein in nigral dopaminergic neurons demonstrated a correlation between α-synuclein expression and ferrireductase activity. Furthermore, studies on tissue from Parkinson's disease patient brains showed a significant decrease in ferrireductase activity, possibly due to deposition of large amounts of inactive protein. Cellular studies suggest that increase ferrireductase activity results in increased levels of dopamine metabolites and increased sensitivity to the toxicity of DOPAL. These findings demonstrate that α-synuclein ferrireductase activity is present in vivo and its alteration may play a role in neuron loss in disease

Fluctuations and differential contraction during regeneration of Hydra vulgaris tissue toroids

We studied regenerating bilayered tissue toroids dissected from Hydra vulgaris polyps and relate our macroscopic observations to the dynamics of force-generating mesoscopic cytoskeletal structures. Tissue fragments undergo a specific toroid-spheroid folding process leading to complete regeneration towards a new organism. The time scale of folding is too fast for biochemical signalling or morphogenetic gradients which forced us to assume purely mechanical self-organization. The initial pattern selection dynamics was studied by embedding toroids into hydro-gels allowing us to observe the deformation modes over longer periods of time. We found increasing mechanical fluctuations which break the toroidal symmetry and discuss the evolution of their power spectra for various gel stiffnesses. Our observations are related to single cell studies which explain the mechanical feasibility of the folding process. In addition, we observed switching of cells from a tissue bound to a migrating state after folding failure as well as in tissue injury. We found a supra-cellular actin ring assembled along the toroid's inner edge. Its contraction can lead to the observed folding dynamics as we could confirm by finite element simulations. This actin ring in the inner cell layer is assembled by myosin- driven length fluctuations of supra-cellular {\alpha}-actin structures (myonemes) in the outer cell-layer.Comment: 19 pages and 8 figures, submitted to New Journal of Physic

Heparin and cAMP modulators interact during pre-in vitro maturation to affect mouse and human oocyte meiosis and developmental competence

STUDY QUESTION Does heparin ablate the advantageous effects of cyclic adenosine mono-phosphate (cAMP) modulators during pre-in vitro maturation (IVM) and have a deleterious effect in standard oocyte IVM? SUMMARY ANSWER Heparin interrupts energy metabolism and meiotic progression and adversely affects subsequent development of oocytes under conditions of elevated cAMP levels in cumulus-oocyte complexes (COCs) after pre-IVM treatment with forskolin. WHAT IS KNOWN ALREADY In animal IVM studies, artificial regulation of meiotic resumption by cAMP-elevating agents improves subsequent oocyte developmental competence. Heparin has no effect on spontaneous, FSH- or epidermal growth factor (EGF)-stimulated meiotic maturation. STUDY DESIGN, SIZE, DURATION An in vitro cross-sectional study was conducted using immature mouse and human COCs. Depending on individual experimental design, COCs were treated during pre-IVM with or without heparin, in the presence or absence of forskolin and/or 3-isobutyl-1-methylxanthine (IBMX), and then COC function was assessed by various means. PARTICIPANTS/MATERIALS, SETTINGS, METHODS Forty-two women with polycystic ovaries (PCOs) or polycystic ovarian syndrome (PCOS) donated COCs after oocyte retrieval in a non-hCG-triggered IVM cycle. COCs were collected in pre-IVM treatments and then cultured for 40 h and meiotic progression was assessed. COCs from 21- to 24-day-old female CBA F1 mice were collected 46 h after stimulation with equine chorionic gonadotrophin. Following treatments, COCs were checked for meiotic progression. Effects on mouse oocyte metabolism were measured by assessing oocyte mitochondrial membrane potential using JC-1 staining and oocyte ATP content. Post-IVM mouse oocyte developmental competence was assessed by in vitro fertilization and embryo production. Blastocyst quality was evaluated by differential staining of inner cell mass (ICM) and trophectoderm (TE) layers. MAIN RESULTS AND THE ROLE OF CHANCE In the absence of heparin in pre-IVM culture, the addition of cAMP modulators did not affect human oocyte MII competence after 40 h. In standard IVM, heparin supplementation in pre-IVM did not affect MII competence; however, when heparin was combined with cAMP modulators, MII competence was significantly reduced from 65 to 15% (P < 0.05). In mouse experiments, heparin alone in pre-IVM significantly delayed germinal vesicle breakdown (GVBD) so that fewer GVBDs were observed at 0 and 1 h of IVM (P < 0.05), but not by 2 or 3 h of IVM. Combined treatment with IBMX and forskolin in the pre-IVM medium produced a large delay in GVBD such that no COCs exhibited GVBD in the first 1 h of IVM, and the addition of heparin in pre-IVM further significantly delayed the progression of GVBD (P < 0.05), in a dose-dependent manner (P < 0.01). Combined IBMX and forskolin treatment of mouse COCs during pre-IVM significantly increased mitochondrial membrane potential and ATP production in the oocyte at the end of pre-IVM (P < 0.05), and significantly improved fertilization, embryo development and quality (P < 0.05). However, heparin abolished the IBMX + forskolin-stimulated increase in mitochondrial membrane potential and ATP production (P < 0.05), and adversely affected embryonic cleavage, development rates and embryo quality (P < 0.05). This latter adverse combinational effect was negated when mouse COCs were collected in heparin and IBMX for 15 min, washed and then cultured for 45 min in IBMX and forskolin without heparin. LIMITATION, REASONS FOR CAUTION Experiments in mice found that heparin ablation of the advantageous effects of cAMP modulators during pre-IVM was associated with altered oocyte metabolism, but the mechanism by which heparin affects metabolism remains unclear. WIDER IMPLICATIONS OF THE FINDINGS This study has revealed a novel and unexpected interaction between heparin and cAMP modulators in pre-IVM in immature mouse and human oocytes, and established a means to collect oocytes using heparin...Hai-tao Zeng, Zi Ren, Luis Guzman, Xiaoqian Wang, Melanie L. Sutton-McDowall, Lesley J. Ritter, Michel De Vos, Johan Smitz, Jeremy G. Thompson, and Robert B. Gilchris

Microtubules in Bacteria: Ancient Tubulins Build a Five-Protofilament Homolog of the Eukaryotic Cytoskeleton

Microtubules play crucial roles in cytokinesis, transport, and motility, and are therefore superb targets for anti-cancer drugs. All tubulins evolved from a common ancestor they share with the distantly related bacterial cell division protein FtsZ, but while eukaryotic tubulins evolved into highly conserved microtubule-forming heterodimers, bacterial FtsZ presumably continued to function as single homopolymeric protofilaments as it does today. Microtubules have not previously been found in bacteria, and we lack insight into their evolution from the tubulin/FtsZ ancestor. Using electron cryomicroscopy, here we show that the tubulin homologs BtubA and BtubB form microtubules in bacteria and suggest these be referred to as “bacterial microtubules” (bMTs). bMTs share important features with their eukaryotic counterparts, such as straight protofilaments and similar protofilament interactions. bMTs are composed of only five protofilaments, however, instead of the 13 typical in eukaryotes. These and other results suggest that rather than being derived from modern eukaryotic tubulin, BtubA and BtubB arose from early tubulin intermediates that formed small microtubules. Since we show that bacterial microtubules can be produced in abundance in vitro without chaperones, they should be useful tools for tubulin research and drug screening