Remote Detection of Radioactive Material on the Basis of the Plasma Breakdown Using High-Power Millimeter-Wave Source

Department of PhysicsThis thesis demonstrates the possibility of remote detection of radioactive material in long distance using high-power millimeter/THz wave source, gyrotron. It has been encouraged by a limitation of the current technologies which can only detect in short distance, about few meters, from the source. This proposed novel idea is based on ambient free electron density in the vicinity of the radioactive source. There are only a few free electrons in normal atmospheric air condition (~ 10 electrons/cm3). However, the electron density increases exponentially with radioactive material owing to the Compton scattering among the radiation from the source and air molecules. High density of average free electrons indirectly indicates the presence of the field enhancing factor such as radioactivity. The focused high-power millimeter-wave beam near the source induce the plasma avalanche ionization. As the millimeter-wave source, our laboratory-made gyrotron operates at 95 GHz and tens of kilowatts with 20 ??s of pulse duration. In the experiments, we concentrate on the plasma avalanche delay time, from an appearance of a seed electron up to the emission of the light induced by the breakdown discharge. Beginning with the argon (Ar) discharge phenomena, plasma image, velocity, and spectroscopy were observed without external source. Based on the Paschen curve, which indicates the required electric field for the breakdown, the reduced threshold electric fields were experienced with a radioactive source. Besides, measurements of the eliminated statistical delay time lead to the existence of the radioactive material. Interestingly, even though the induced electromagnetic (EM) field was much lower than the threshold field, the attenuated radio frequency (RF) signal was measured in atmospheric air condition. These new experimental results were sufficient evidence to indicate the possibility of the remote detection of radioactive material. By measuring the breakdown discharge induced by the high-power pulsed millimeter-wave radiation, the detection range of our method can be extended to the kilometer range involving with the proper size of an antenna and simply weak turbulence. Furthermore, the detection sensitivity of the method is 4000 times higher than that suggested by theoretical calculationsthis is achieved by measuring the plasma breakdown delay time with plasma on/off phenomenon. Our results provide a technical breakthrough in the remote sensing of radioactive material, which should not only be useful in the development of high-power EM wave sources but also directly affect the security aspects of modern life.ope

Cuatro nuevas especies de Pycnophyes (Kinorhyncha: Homalorhagida) de Corea y el mar del este de China

Four new species of Pycnophyes are described from Korean waters and the East China Sea. Pycnophyes pardosi n. sp. is distinguished from other congeners by the presence of a single paradorsal seta on segments 2-8 and a pair on segment 9, combined with the presence of longitudinal cuticular thickenings on the dorsal and ventral sides of segment 10. Pycnophyes chalgap n. sp. is easily distinguished by the shape of its midsternal plate with the rounded posterior margin, extending beyond and overlapping half of the following segment. Pycnophyes cristatus n. sp. is recognized by its lack of ventromedial setae on segments 3-6 combined with the presence of pointed middorsal processes that turn progressively longer towards the posterior segments from segment 6. The process on segment 10 is conspicuously long, extending beyond the posterior margin of segment 11. Pycnophyes smaug n. sp. is distinguished by its general scarcity of setae which, with the exception of those in lateroventral positions, only appear in laterodorsal positions on segments 2 and 9 and in ventromedial position on segment 9. The description of four additional species brings the total number of valid kinorhynch species around the Korean Peninsula up to 26.Se describen cuatro nuevas especies de aguas coreanas y del este del mar de China. Pycnophyes pardosi n. sp. se distingue de las demás especies por la presencia de una única seda paradorsal en los segmentos 2-8 y un par en el segmento 9, combinado con la presencia de engrosamientos cuticulares longitudinales en el lado dorsal y ventral del segmento 10. Pycnophyes chalgap n. sp. es fácilmente distinguible por la forma de su placa medioesternal con el margen posterior redondeado, sobrepasando y solapando la mitad anterior del siguiente segmento. Pycnophyes cristatus n. sp. es reconocible por la ausencia de sedas ventromediales en los segmentos 3-6 combinado con la presencia de salientes mediodorsales puntiagudos que a partir del segmento 6 se vuelven progresivamente más largos hacia los segmentos posteriores. El saliente del segmento 10 es llamativamente largo, extendiéndose más allá del margen posterior del segmento 11. Pycnophyes smaug n. sp. se distingue por su carencia general de sedas que, aparte de las lateroventrales, solo aparecen en posición laterodorsal en los segmentos 2 y 9, y en posición ventromedial en el segmento 9. La descripción de las cuatro especies aumenta hasta 26 el número total de especies válidas de kinorrincos entorno a la península coreana

First transcriptome assembly of a newly discovered vent mussel, Gigantidas vrijenhoeki, at Onnuri Vent Field on the northern Central Indian Ridge

This is the first report of a transcriptome assembly of a newly discovered hydrothermal vent mussel, Gigantidas vrijenhoeki (Bivalvia: Mytilidae), on the Central Indian Ridge. Gigantidas vrijenhoeki was identified from material collected at the newly discovered Onnuri Vent Field (OVF) on the Central Indian Ridge in 2018, and was reported as a new species, distinct from another dominant hydrothermal vent mussel, Bathymodiolus marisindicus, in 2020. We sequenced the transcriptome of G. vrijenhoeki using the Illumina HiSeq X System. De novo assembly and analysis of the coding regions predicted 25,405 genes, 84.76% of which was annotated by public databases. The transcriptome of G. vrijenhoeki will be a valuable resource in studying the ecological and biological characteristics of this new species, which is distinct from other deep-sea mussels. These data should also support the investigation of the relationship between the environmental conditions of hydrothermal vents and the unique distribution of G. vrijenhoeki in the OVF of the Central Indian Ridge

Quantitative determinants of aerobic glycolysis identify flux through the enzyme GAPDH as a limiting step

Aerobic glycolysis or the Warburg Effect (WE) is characterized by the increased metabolism of glucose to lactate. It remains unknown what quantitative changes to the activity of metabolism are necessary and sufficient for this phenotype. We developed a computational model of glycolysis and an integrated analysis using metabolic control analysis (MCA), metabolomics data, and statistical simulations. We identified and confirmed a novel mode of regulation specific to aerobic glycolysis where flux through GAPDH, the enzyme separating lower and upper glycolysis, is the rate-limiting step in the pathway and the levels of fructose (1,6) bisphosphate (FBP), are predictive of the rate and control points in glycolysis. Strikingly, negative flux control was found and confirmed for several steps thought to be rate-limiting in glycolysis. Together, these findings enumerate the biochemical determinants of the WE and suggest strategies for identifying the contexts in which agents that target glycolysis might be most effective. DOI: http://dx.doi.org/10.7554/eLife.03342.00