6,085 research outputs found
メダカにおける実用的なノックインシステムの確立とその応用
京都大学0048新制・課程博士博士(農学)甲第22503号農博第2407号新制||農||1077(附属図書館)学位論文||R2||N5283(農学部図書室)京都大学大学院農学研究科応用生物科学専攻(主査)教授 佐藤 健司, 教授 澤山 茂樹, 准教授 豊原 治彦学位規則第4条第1項該当Doctor of Agricultural ScienceKyoto UniversityDGA
Extreme case of Faraday effect: magnetic splitting of ultrashort laser pulses in plasmas
The Faraday effect, caused by a magnetic-field-induced change in the optical
properties, takes place in a vast variety of systems from a single atomic layer
of graphenes to huge galaxies. Currently, it plays a pivot role in many
applications such as the manipulation of light and the probing of magnetic
fields and material's properties. Basically, this effect causes a polarization
rotation of light during its propagation along the magnetic field in a medium.
Here, we report an extreme case of the Faraday effect where a linearly
polarized ultrashort laser pulse splits in time into two circularly polarized
pulses of opposite handedness during its propagation in a highly magnetized
plasma. This offers a new degree of freedom for manipulating ultrashort and
ultrahigh power laser pulses. Together with technologies of ultra-strong
magnetic fields, it may pave the way for novel optical devices, such as
magnetized plasma polarizers. In addition, it may offer a powerful means to
measure strong magnetic fields in laser-produced plasmas.Comment: 18 pages, 5 figure
Development of an efficient bioreactor system for delivering foreign proteins secreted from liver into eggs with a vitellogenin signal in medaka Oryzias latipes
In this study, we developed a novel bioreactor system to deliver and accumulate foreign proteins in eggs using medaka fish Oryzias latipes with the aid of a partial sequence of vitellogenin (Vtg). In teleost fish, Vtg, the hepatically generated precursor of egg yolk proteins, is secreted into the bloodstream and then taken up into eggs. We predicted in silico a probable region (Vtg signal) of Vtg that mediates transportation of proteins from the liver into eggs. Then, we established two transgenic lines expressing the fused proteins including the Vtg signal and each reporter gene, enhanced green fluorescent protein (EGFP) or firefly luciferase (LUC)-fused EGFP, in the liver driven by a liver-specific choriogeninH (chgH) promoter. Each reporter signal was detected from the fertilized eggs spawned by the transgenic females, showing successful transportation of the proteins into the eggs with the Vtg signal. This is the first report demonstrating that the Vtg signal has capability to deliver exogenous proteins into eggs. Because Vtg is a highly conserved protein among most of oviparous organisms, our findings hold promise for establishing bioreactor systems viable in a wide range of organisms
Dense blocks of energetic ions driven by multi-petawatt lasers
Laser-driven ion accelerators have the advantages of compact size, high
density, and short bunch duration over conventional accelerators. Nevertheless,
it is still challenging to simultaneously enhance the yield and quality of
laser-driven ion beams for practical applications. Here we propose a scheme to
address this challenge via the use of emerging multi-petawatt lasers and a
density-modulated target. The density-modulated target permits its ions to be
uniformly accelerated as a dense block by laser radiation pressure. In
addition, the beam quality of the accelerated ions is remarkably improved by
embedding the target in a thick enough substrate, which suppresses hot electron
refluxing and thus alleviates plasma heating. Particle-in-cell simulations
demonstrate that almost all ions in a solid-density plasma of a few microns can
be uniformly accelerated to about 25% of the speed of light by a laser pulse at
an intensity around 1022 W/cm2. The resulting dense block of energetic ions may
drive fusion ignition and more generally create matter with unprecedented high
energy density.Comment: 18 pages, 4 figure
The perineuronal proteoglycan surface coat in the adult rat brain, with special reference to its reactions to Gomori's ammoniacal silver.
The present study showed that many neurons in the adult rat brain possessed a perineuronal sulfated proteoglycan surface coat which reacted to cationic iron colloid and aldehyde fuchsin. This surface coat was stained supravitally with Ehrlich's methylene blue and doubly stained with Ehrlich's methylene blue and aldehyde fuchsin. The surface coat was also stained with Gomori's ammoniacal silver and doubly stained with Gomori's ammoniacal silver and cationic iron colloid. The surface coat was usually expressed together with a nerve cell surface glycoprotein net detectable with lectin Wisteria floribunda agglutinin. These findings indicate that the perineuronal proteoglycan surface coat is identical to Cajal's superficial reticulum and contains some collagenous elements. It was further demonstrated that collagenase digestion erased Gomori's ammoniacal silver impregnation within the perineuronal proteoglycan surface coat.</p
The Recent Overview and Prospects of Nuclear Power Policy and Industrial Strategies in the UK, Italy and Sweden
European countries that had moved away from nuclear energy or frozen the construction of new nuclear power plants have begun to return to the construction due to their pursuit of low-carbon electricity sources, energy security and requirements for replacements for existing nuclear plants. Particularly, we should pay attention to developments in the UK that vowed to launch the construction of new nuclear power plants in its 2007 Energy White Paper, and in Italy and Sweden that have begun to reconsider their legal ban on new nuclear plants. These countries launched nuclear power generation development comparatively in the early stage in the world, and built solid nuclear industry infrastructure, however after that, suspended the construction of new nuclear power plants for energy-related or economic reasons. In view of recent conditions, however, they are trying to reintroduce nuclear energy or expand nuclear energy use. Given these points, the three countries are viewed as symbols of Europes return to nuclear energy.nuclear energy, nuclear power, regulation, energy security, carbon emissions
Effective continuous model for surface states and thin films of three dimensional topological insulators
Two-dimensional effective continuous models are derived for the surface
states and thin films of the three-dimensional topological insulator (3DTI).
Starting from an effective model for 3DTI based on the first principles
calculation [Zhang \emph{et al}, Nat. Phys. 5, 438 (2009)], we present
solutions for both the surface states in a semi-infinite boundary condition and
in the thin film with finite thickness. An effective continuous model was
derived for surface states and the thin film 3DTI. The coupling between
opposite topological surfaces and structure inversion asymmetry (SIA) give rise
to gapped Dirac hyperbolas with Rashba-like splittings in energy spectrum.
Besides, the SIA leads to asymmetric distributions of wavefunctions along the
film growth direction, making some branches in the energy spectra much harder
than others to be probed by light. These features agree well with the recent
angle-resolved photoemission spectra of BiSe films grown on SiC
substrate [Zhang et al, arXiv: 0911.3706]. More importantly, we use the
effective model to fit the experimental data and determine the model
parameters. The result indicates that the thin film BiSe lies in
quantum spin Hall region based on the calculation of the Chern number and the
invariant. In addition, strong SIA always intends to destroy the
quantum spin Hall state.Comment: 12 pages, 7 figures, references are update
Myxedema coma accompanied by sick sinus syndrome and hypoventilation: A case report
Myxedema coma is an emergency presentation of hypothyroidism, and cardiopulmonary manifestations of the disease are related to a high mortality rate. We herein report a case of myxedema coma accompanied by sick sinus syndrome requiring temporary cardiac pacing and hypercapnic respiratory failure in an 87-year-old woman. This case is unique because both of the cardiac and pulmonary manifestations were reversible and successfully treated with thyroid hormone replacement. Our case indicates that early detection of the condition and administration of levothyroxine are essential to improve the life-threatening condition and avoid invasive treatment such as permanent pacemaker implantation or intubation
Three dimensionality of pulsed second-sound waves in He II
Three dimensionality of 3D pulsed second sound wave in He II emitted from a
finite size heater is experimentally investigated and theoretically studied
based on two-fluid model in this study. The detailed propagation of 3D pulsed
second sound wave is presented and reasonable agreement between the
experimental and theoretical results is obtained. Heater size has a big
influence on the profile of 3D second sound wave. The counterflow between the
superfluid and normal fluid components becomes inverse in the rarefaction of 3D
second sound wave. The amplitude of rarefaction decreases due to the
interaction between second sound wave and quantized vortices, which explains
the experimental results about second sound wave near [Phys. Rev. Lett. 73,
2480 (1994)]. The accumulation of dense quantized vortices in the vicinity of
heater surface leads to the formation of a thermal boundary layer, and further
increase of heating duration results in the occurrence of boiling phenomena.
PACS numbers: 67.40.Pm 43.25.+y 67.40.BzComment: 30 pages, 9 figures. Physical Review B, Accepte
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