5,731 research outputs found
Preparation of macroscopic quantum superposition states of a cavity field via coupling to a superconducting charge qubit
We propose how to generate macroscopic quantum superposition states using a
microwave cavity containing a superconducting charge qubit. Based on the
measurement of charge states, we show that the superpositions of two
macroscopically distinguishable coherent states of a single-mode cavity field
can be generated by a controllable interaction between a cavity field and a
charge qubit. After such superpositions of the cavity field are created, the
interaction can be switched off by the classical magnetic field, and there is
no information transfer between the cavity field and the charge qubit. We also
discuss the generation of the superpositions of two squeezed coherent states.Comment: 6 page
Adaptive Noise Reduction of Scintigrams with a Wavelet Transform
The aim of this study was to eliminate the effect of Poisson noise in scintigrams with a wavelet thresholding method. We developed a new noise reduction method with a wavelet transform. The proposed method was a combination of the translation-invariant denoising method and our newly introduced denoising filter which was applicable for Poisson noise. To evaluate the validity of our proposed method, phantom images and scintigrams were used. The results with the phantom images showed that our method was better than conventional methods in terms of the peak signal-to-noise ratio by 3 dB. Quality of the scintigrams processed with our method was better than that with the conventional methods in terms of reducing Poisson noise while preserving edge components. The results demonstrated that the proposed method was effective for the reduction of Poisson noise in scintigrams
Protocol for Extraction and Electron Microscopy Visualization of Lipids in Viburnum tinus Fruit Using Cryo-Ultramicrotomy.
We recently reported that Viburnum tinus fruit generates its metallic blue color using globular lipid inclusions embedded in its epicarpal cell walls. This protocol describes steps to visualize the lipidic nature of the nanostructure using cryo-ultramicrotomy, chloroform extraction, and transmission electron microscopy (TEM) imaging. This method is useful to localize and characterize novel lipidic nanostructures embedded in both plant and animal tissues at the TEM resolution. For complete details on the use and execution of this protocol, please refer to Middleton et al. (2020)
Observation of large many-body Coulomb interaction effects in a doped quantum wire
We demonstrate strong one dimensional (1-D) many-body interaction effects in
photoluminescence (PL) in a GaAs single quantum wire of unprecedented optical
quality, where 1-D electron plasma densities are controlled via electrical
gating. We observed PL of 1-D charged excitons with large binding energy of 2.3
meV relative to the neutral excitons, and its evolution to a Fermi-edge
singularity at high electron density. Furthermore, we find a strong band-gap
renormalization in the 1-D wire, or a large red-shift of PL with increased
electron plasma density. Such a large PL red-shift is not observed when we
create a high density neutral electron-hole plasma in the same wire, due
probably to cancellation of the Coulomb interaction energy in the neutral
plasma.Comment: 5 pages, 4 figures, RevTeX, to be published in Solid State
Communication
FZL, a dynamin-like protein localized to curved grana edges, is required for efficient photosynthetic electron transfer in Arabidopsis
Photosynthetic electron transfer and its regulation processes take place on thylakoid membranes, and the thylakoid of vascular plants exhibits particularly intricate structure consisting of stacked grana and flat stroma lamellae. It is known that several membrane remodeling proteins contribute to maintain the thylakoid structure, and one putative example is FUZZY ONION LIKE (FZL). In this study, we re-evaluated the controversial function of FZL in thylakoid membrane remodeling and in photosynthesis. We investigated the sub-membrane localization of FZL and found that it is enriched on curved grana edges of thylakoid membranes, consistent with the previously proposed model that FZL mediates fusion of grana and stroma lamellae at the interfaces. The mature fzl thylakoid morphology characterized with the staggered and less connected grana seems to agree with this model as well. In the photosynthetic analysis, the fzl knockout mutants in Arabidopsis displayed reduced electron flow, likely resulting in higher oxidative levels of Photosystem I (PSI) and smaller proton motive force (pmf). However, nonphotochemical quenching (NPQ) of chlorophyll fluorescence was excessively enhanced considering the pmf levels in fzl, and we found that introducing kea3-1 mutation, lowering pH in thylakoid lumen, synergistically reinforced the photosynthetic disorder in the fzl mutant background. We also showed that state transitions normally occurred in fzl, and that they were not involved in the photosynthetic disorders in fzl. We discuss the possible mechanisms by which the altered thylakoid morphology in fzl leads to the photosynthetic modifications
Intrastriatal Memantine Infusion
Although the administration of dopamine precursor levodopa remains as the mainstay for the treatment of Parkinson’s disease, long-term exposure to levodopa often causes a disabling complication, referred to as levodopa-induced dyskinesias. Therefore, the development of new therapeutic interventions to dampen levodopa-induced dyskinesias and parkinsonian motor deficits is needed in the treatment of Parkinson’s disease. Intracerebral brain infusion has the merit of being able to specifically deliver any drug into any brain part. By using an intracerebral infusion system equipped with implantable, programmable, and refillable pumps, we show herein that continuous intrastriatal administration of memantine (MMT), which is a non-competitive N-methyl-D-aspartate receptor antagonist, attenuates levodopa-induced dyskinesias and parkinsonian signs in 6-hydroxydopamine-lesioned hemiparkinsonian mice that received daily levodopa treatment. Corroborating the general thought that overactivation of the striatal N-methyl-D-aspartate receptor function might generate levodopa-induced dyskinesias and parkinsonism, our results suggest that a continuous intrastriatal MMT infusion can be beneficial for the management of Parkinson’s disease with levodopa-induced dyskinesias. Our study also provides indications for the prototypic use of pharmacological deep-brain modulation through intracerebral infusion systems for treating medically intractable movement disorders
Video-based assessments of the hind limb stepping in a mouse model of hemi-parkinsonism
Unilateral injection of 6-hydroxydopamine (6-OHDA) is commonly used to generate a rodent model of Parkinson’s disease (PD). Although motor deficits of the lower extremities represent one of the major clinical symptoms in PD patients, validated tests for assessing motor impairments of the hind limb in 6-OHDA mice are currently unavailable. We here report the video-based assessments of the asymmetric use of hind limbs in 6-OHDA mice. A significantly decreased number of spontaneous hind limb stepping was observed in the contralateral-to-lesioned side, and was dose dependently reversed by levodopa, suggesting that it could be utilized for screening PD therapeutics
Recyclable nanocomposites of well-dispersed 2D layered silicates in cellulose nanofibril (CNF) matrix
Nanocomposites based on components from nature, which can be recycled are of great interest in new materials
for sustainable development. The range of properties of nacre-inspired hybrids of 1D cellulose and 2D clay
platelets are investigated in nanocomposites with improved nanoparticle dispersion in the starting hydrocolloid
mixture. Films with a wide range of compositions are prepared by capillary force assisted physical assembly
(vacuum-assisted filtration) of TEMPO-oxidized cellulose nanofibers (TOCN) reinforced by exfoliated nanoclays
of three different aspect ratios: saponite, montmorillonite and mica. X-ray diffraction and transmission electron
micrographs show almost monolayer dispersion of saponite and montmorillonite and high orientation parallel to
the film surface. Films exhibit ultimate strength up to 573 MPa. Young's modulus exceeds 38 GPa even at high
MTM contents (40–80 vol%). Optical transmittance, UV-shielding, thermal shielding and fire-retardant prop-
erties are measured, found to be very good and are sensitive to the 2D nanoplatelet dispersion
Spin Gap in a Doped Kondo Chain
We show that the Kondo chain away from half-filling has a spin gap upon the
introduction of an additional direct Heisenberg coupling between localized
spins. This is understood in the weak-Kondo-coupling limit of the
Heisenberg-Kondo lattice model by bosonization and in the strong-coupling limit
by a mapping to a modified t-J model. Only for certain ranges of filling and
Heisenberg coupling does the spin gap phase extend from weak to strong
coupling.Comment: 4 pages RevTeX including 4 eps figures; minor corrections and
clarification
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