146 research outputs found
Lokiarchaeota archaeon schizorhodopsin-2 (LaSzR2) is an inward proton pump displaying a characteristic feature of acid-induced spectral blue-shift
The photoreactive protein rhodopsin is widespread in microorganisms and has a variety of photobiological functions. Recently, a novel phylogenetically distinctive group named 'schizorhodopsin (SzR)' has been identified as an inward proton pump. We performed functional and spectroscopic studies on an uncharacterised schizorhodopsin from the phylum Lokiarchaeota archaeon. The protein, LaSzR2, having an all-trans-retinal chromophore, showed inward proton pump activity with an absorption maximum at 549 nm. The pH titration experiments revealed that the protonated Schiff base of the retinal chromophore (Lys188, pK(a)=12.3) is stabilised by the deprotonated counterion (presumably Asp184, pK(a)=3.7). The flash-photolysis experiments revealed the presence of two photointermediates, K and M. A proton was released and uptaken from bulk solution upon the formation and decay of the M intermediate. During the M-decay, the Schiff base was reprotonated by the proton from a proton donating residue (presumably Asp172). These properties were compared with other inward (SzRs and xenorhodopsins, XeRs) and outward proton pumps. Notably, LaSzR2 showed acid-induced spectral 'blue-shift' due to the protonation of the counterion, whereas outward proton pumps showed opposite shifts (red-shifts). Thus, we can distinguish between inward and outward proton pumps by the direction of the acid-induced spectral shift
Characteristics of Clinical and Imaging Findings of Epidermoid Cysts under the Skin of the Mental Region
Epidermoid cyst often arises in the fl oor of oral cavity; however, it is relatively rare to arise subcutaneously in the mental region. We reported characteristics of clinical and imaging fi ndings of epidermoid cysts under the skin of the mental region. The patient was a 53-year-old male. He complained of a subcutaneous mass without pain in the left mental region. A palpable soft and movable thumb-sized mass without pain was observed at the fi rst examination. Ultrasound examination revealed a well-demarcated mass with heterogenous hyper-echoic internal echo and posterior echo enhancement. On power Doppler sonography, a small amount of blood supply was found around the periphery of the mass. Plain CT scan revealeda globular soft-tissue mass with peripheral high and central low CT values area. The mass was removed under local anesthesia using intraoral approach. A histopathologic diagnosis was epidermoid cyst. Recurrence is not observed 2 years after surgery. There were only 3 reports of epidermoid cysts in the mental region, including our case in Japan, clinically characteristics of age ranging 20 to 66 years of age and the mean age of 46 years, with 2 males and 1 female. The size wasfrom 20 mm to 12 mm in diameter and from the tip of a thumb up to the tip of a small fi nger. Ultrasound images of the inside of epidermoid cysts that we experienced this time showed enhancement of relatively uniform hyperechoic image and posterior echo, which was characteristically slightly diff erent from fi ndings of epidermoid cysts generally reported
Toward Identification of Order Parameters in Skutterudites - a Wonderland of Strong Correlation Physics -
Current status is described toward identifying unconventional order
parameters in filled skutterudites with unique ordering phenomena. The order
parameters in PrFeP and PrRuP are discussed in relation
to associated crystalline electric field (CEF) states and angular form factors.
By phenomenological Landau analysis, it is shown that a scalar order model
explains most properties in both PrFeP and PrRuP with
very different magnetic properties. In particular, the highly anisotropic
susceptibility induced by uniaxial pressure in PrFeP is explained in
terms of two types of couplings. In the case of SmRuP, the main
order parameter at low field is identified as magnetic octupoles. A microscopic
mechanism is proposed how the dipole and octupole degrees of freedom mix under
the point group of skutterudites.Comment: To be published in Proc. International Conference on New Quantum
Phenomena in Skutterudite and Related Systems (Suppl. J. Phys. Soc. Jpn 78,
2008
Lateral–Medial Dissociation in Orbitofrontal Cortex–Hypothalamus Connectivity
The orbitofrontal cortex (OFC) is involved in cognitive functions, and is also closely related to autonomic functions. The OFC is densely connected with the hypothalamus, a heterogeneous structure controlling autonomic functions that can be divided into two major parts: the lateral and the medial. Resting-state functional connectivity has allowed us to parcellate the cerebral cortex into putative functional areas based on the changes in the spatial pattern of connectivity in the cerebral cortex when a seed point is moved from one voxel to another. In the present high spatial-resolution fMRI study, we investigate the connectivity-based organization of the OFC with reference to the hypothalamus. The OFC was parcellated using resting-state functional connectivity in an individual subject approach, and then the functional connectivity was examined between the parcellated areas in the OFC and the lateral/medial hypothalamus. We found a functional double dissociation in the OFC: the lateral OFC (the lateral orbital gyrus) was more likely connected with the lateral hypothalamus, whereas the medial OFC (the medial orbital and rectal gyri) was more likely connected with the medial hypothalamus. These results demonstrate the fundamental heterogeneity of the OFC, and suggest a potential neural basis of the OFC-hypothalamic functional interaction
Scalar order: possible candidate for order parameters in skutterudites
Phenomenological Landau analysis shows that the properties of ordered phases
in some skutterudites are consistently accounted for by a scalar order
parameter which preserves the cubic symmetry, even in the ordered phase. A
universal value is found for the anisotropy ratio of the transition temperature
in a magnetic field, homogeneous magnetization, and induced staggered
magnetization. The difference in magnetic behavior between PrFeP and
PrRuP near their phase transitions is explained within a single
framework. For the low-field phase of PrFeP, the scalar order with
the symmetry can explain (i) the absence of field induced dipoles
perpendicular to the magnetic field, (ii) isotropic magnetic susceptibility in
the ordered phase, (iii) the field angle dependence of the transition
temperature, and (iv) the splitting pattern of the P nuclear magnetic
resonance (NMR) spectra. It is proposed how the order parameter in
SmRuP is identified by NMR analysis of a single crystal.Comment: 4 pages, 4 figure
Multipole State of Heavy Lanthanide Filled Skutterudites
We discuss multipole properties of filled skutterudites containing heavy
lanthanide Ln from a microscopic viewpoint on the basis of a seven-orbital
Anderson model. For Ln=Gd, in contrast to naive expectation, quadrupole moments
remain in addition to main dipole ones. For Ln=Ho, we find an exotic state
governed by octupole moment. For Ln=Tb and Tm, no significant multipole moments
appear at low temperatures, while for Ln=Dy, Er, and Yb, dipole and
higher-order multipoles are dominant. We briefly discuss possible relevance of
these multipole states with actual materials.Comment: 5 pages, 3 figure
A novel GTPase, CRAG, mediates promyelocytic leukemia protein–associated nuclear body formation and degradation of expanded polyglutamine protein
Polyglutamine diseases are inherited neurodegenerative diseases caused by the expanded polyglutamine proteins (polyQs). We have identified a novel guanosine triphosphatase (GTPase) named CRAG that contains a nuclear localization signal (NLS) sequence and forms nuclear inclusions in response to stress. After ultraviolet irradiation, CRAG interacted with and induced an enlarged ring-like structure of promyelocytic leukemia protein (PML) body in a GTPase-dependent manner. Reactive oxygen species (ROS) generated by polyQ accumulation triggered the association of CRAG with polyQ and the nuclear translocation of the CRAG–polyQ complex. Furthermore, CRAG promoted the degradation of polyQ at PML/CRAG bodies through the ubiquitin–proteasome pathway. CRAG knockdown by small interfering RNA in neuronal cells consistently blocked the nuclear translocation of polyQ and enhanced polyQ-mediated cell death. We propose that CRAG is a modulator of PML function and dynamics in ROS signaling and is protectively involved in the pathogenesis of polyglutamine diseases
Microscopic Aspects of Multipole Properties of Filled Skutterudites
We discuss low-temperature multipole states of Nd-based filled skutterudites
by analyzing a multiorbital Anderson model with the use of a numerical
renormalization group method. In order to determine the multipole state, we
take a procedure to maximize the multipole susceptibility matrix. Then, it is
found that the dominant multipole state is characterized by the mixture of 4u
magnetic and 5u octupole moments. The secondary state is specified by 2u
octupole. When we further take into account the coupling between electrons
in degenerate () orbitals and dynamical
Jahn-Teller phonons with symmetry, quadrupole fluctuations become
significant at low temperatures in the mixed multipole state with 4u magnetic
and 5u octupole moments. Finally, we briefly discuss possible relevance of the
present results to actual Nd-based filled skutterudite compounds.Comment: 6 pages, 3 figures. To appear in the Proceedings of the 17th
International Conference on Magnetism (ICM2006
Fabrication of Fe-based ribbon with controlled permeability by Joule heating under tensile stress
We prepared an Fe-based ribbon with controlled permeability and low magnetic loss by Continuous Stress-Annealing by Joule Heating (CSA-JH) method. The shortest annealing time necessary for the obtaining of the ribbons with completely developed anisotropy was 1 sec, but in order to obtain the sufficiently crystallized ribbons with small saturation magnetostriction it is required to perform annealing longer than 2 sec. A toroidal core was prepared from a long ribbon with controlled permeability and small saturation magnetostriction, and the magnetic loss and relative permeability of the core were evaluated in the frequency range of 0.1 - 3 MHz. The permeability was kept constant up to 2 MHz, and the magnetic loss is lower than that for other types of core with a similar permeability value. These results suggest that the CSA-JH method is a promising method for realizing an Fe-based core with excellent magnetic properties.Proceedings of the 18th International Symposium on Soft Magnetic Material
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