100 research outputs found
Exact results on ABJ theory and the refined topological string
We study the partition function of the ABJ theory, which is the N=6
superconformal Chern-Simons matter theory with gauge group U(N)xU(N+M) and
Chern-Simons levels (k,-k). We exactly compute the ABJ partition function on a
three sphere for various k, M and N via the Fermi gas approach. By using these
exact data, we show that the ABJ partition function is completely determined by
the refined topological string on local P^1 x P^1, including membrane instanton
effects in the M-theory dual.Comment: 24+29 pages, 4 figures; v2:minor improvement
Large N non-perturbative effects in superconformal Chern-Simons theories
We investigate the large instanton effects of partition functions in a
class of circular quiver Chern-Simons theories on a
three-sphere. Our analysis is based on the supersymmetry localization and the
Fermi-gas formalism. The resulting matrix model can be regarded as a
two-parameter deformation of the ABJM matrix model, and has richer
non-perturbative structures. Based on a systematic semi-classical analysis, we
find analytic expressions of membrane instanton corrections. We also exactly
compute the partition function for various cases and find some exact forms of
worldsheet instanton corrections, which appear as quantum mechanical
non-perturbative corrections in the Fermi-gas system.Comment: 35+18 pages, 3 figures; v2: minor correction
ABJM Wilson Loops in Arbitrary Representations
We study vacuum expectation values (VEVs) of circular half BPS Wilson loops
in arbitrary representations in ABJM theory. We find that those in hook
representations are reduced to elementary integrations thanks to the Fermi gas
formalism, which are accessible from the numerical studies similar to the
partition function in the previous studies. For non-hook representations, we
show that the VEVs in the grand canonical formalism can be exactly expressed as
determinants of those in the hook representations. Using these facts, we can
study the instanton effects of the VEVs in various representations. Our results
are consistent with the worldsheet instanton effects studied from the
topological string and a prescription to include the membrane instanton effects
by shifting the chemical potential, which has been successful for the partition
function.Comment: 30 pages, 1 figure; v2: references added; v3: minor correction
Multiscale expansion of the lattice potential KdV equation on functions of infinite slow-varyness order
We present a discrete multiscale expansion of the lattice potential
Korteweg-de Vries (lpKdV) equation on functions of infinite order of
slow-varyness. To do so we introduce a formal expansion of the shift operator
on many lattices holding at all orders. The lowest secularity condition from
the expansion of the lpKdV equation gives a nonlinear lattice equation,
depending on shifts of all orders, of the form of the nonlinear Schr\"odinger
(NLS) equationComment: 9 pages, submitted to Journ. Phys.
Basal ganglia-cortical connectivity underlies self-regulation of brain oscillations in humans
Brain-Computer Interface操作の得手不得手に関わる脳回路を発見 --操作を「考える」か「感じる」か、個人差に合わせた技術開発へ期待--. 京都大学プレスリリース. 2022-08-10.Brain-computer interfaces provide an artificial link by which the brain can directly interact with the environment. To achieve fine brain-computer interface control, participants must modulate the patterns of the cortical oscillations generated from the motor and somatosensory cortices. However, it remains unclear how humans regulate cortical oscillations, the controllability of which substantially varies across individuals. Here, we performed simultaneous electroencephalography (to assess brain-computer interface control) and functional magnetic resonance imaging (to measure brain activity) in healthy participants. Self-regulation of cortical oscillations induced activity in the basal ganglia-cortical network and the neurofeedback control network. Successful self-regulation correlated with striatal activity in the basal ganglia-cortical network, through which patterns of cortical oscillations were likely modulated. Moreover, basal ganglia-cortical network and neurofeedback control network connectivity correlated with strong and weak self-regulation, respectively. The findings indicate that the basal ganglia-cortical network is important for self-regulation, the understanding of which should help advance brain-computer interface technology
A calmodulin inhibitor, W-7 influences the effect of cyclic adenosine 3', 5'-monophosphate signaling on ligninolytic enzyme gene expression in Phanerochaete chrysosporium
The capacity of white-rot fungi to degrade wood lignin may be highly applicable to the development of novel bioreactor systems, but the mechanisms underlying this function are not yet fully understood. Lignin peroxidase (LiP) and manganese peroxidase (MnP), which are thought to be very important for the ligninolytic property, demonstrated increased activity in Phanerochaete chrysosporium RP-78 (FGSC #9002, ATCC MYA-4764™) cultures following exposure to 5 mM cyclic adenosine 3', 5'-monophosphate (cAMP) and 500 μM 3'-isobutyl-1-methylxanthine (IBMX), a phosphodiesterase inhibitor. Real-time reverse transcription polymerase chain reaction (RT-PCR) analysis revealed that transcription of most LiP and MnP isozyme genes was statistically significantly upregulated in the presence of the cAMP and IBMX compared to the untreated condition. However, 100 μM calmodulin (CaM) inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), which had insignificant effects on fungal growth and intracellular cAMP concentration, not only offset the increased activity and transcription induced by the drugs, but also decreased them to below basal levels. Like the isozyme genes, transcription of the CaM gene (cam) was also upregulated by cAMP and IBMX. These results suggest that cAMP signaling functions to increase the transcription of LiP and MnP through the induction of cam transcription
Expression of chondroitin-glucuronate C5-epimerase and cellular immune responses in patients with hepatocellular carcinoma
Background & Aims: Chondroitin-glucuronate C5-epimerase is an enzyme that converts D-glucuronic acid to L-iduronic acid residues in dermatan sulphate biosynthesis. It is also identified to be a tumour-associated antigen recognized by cytotoxic T cells (CTLs) and its enhanced expression in many cancers has been reported. In the present study, we investigated the usefulness of this molecule as an immunotherapeutic target in hepatocellular carcinoma (HCC). Methods: The expression of chondroitin-glucuronate C5-epimerase in hepatoma cell lines and HCC tissues was confirmed by immunofluorescence and immunohistochemical analysis. CTL responses were investigated by several immunological techniques using peripheral blood mononuclear cells (PBMCs) or tumour-infiltrating lymphocytes. To determine the safety of immunotherapy using chondroitin-glucuronate C5-epimerase-derived peptide, 12 patients with HCC were administered s.c. vaccinations of the peptides and analysed. Results: Chondroitin-glucuronate C5-epimerase was expressed in HCC cell lines and human tissues including alpha-foetoprotein (AFP)-negative individuals. Chondroitin-glucuronate C5-epimerase-specific CTLs could be generated by stimulating PBMCs of HCC patients with peptides and they showed cytotoxicity against HCC cells expressing the protein. The frequency of CTL precursors investigated by enzyme-linked immunospot (ELISPOT) assay was 0-34 cells/3 × 10 5 PBMCs and the infiltration of interferon-gamma-producing CTLs into the tumour site was confirmed. In the vaccination study, no severe adverse events were observed and the peptide-specific CTLs were induced in 4 of 12 patients tested. Conclusions: Chondroitin-glucuronate C5-epimerase is a potential candidate for tumour antigen with immunogenicity and the peptides derived from this antigen could be useful in HCC immunotherapy. © 2012 John Wiley & Sons A/S
ABJ theory in the higher spin limit
This article is distributed under the terms of the Creative Commons
Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in
any medium, provided the original author(s) and source are creditedArticle funded by SCOAP3 .Article funded by SCOAP3 .The work of SH
was supported in part by the National Research Foundation of South Africa and DSTNRF
Centre of Excellence in Mathematical and Statistical Sciences (CoE-MaSS). Opinions
expressed and conclusions arrived at are those of the author and are not necessarily to be
attributed to the NRF or the CoE-MaSS. The work of KO was supported in part by JSPS
Grant-in-Aid for Young Scientists (B) 23740178. MS is grateful to the Weizmann Institute
for the stimulating environment at the “Black Holes and Quantum Information” workshop.
The work of MS was supported in part by Grant-in-Aid for Young Scientists (B) 24740159
from the Japan Society for the Promotion of Science (JSPS)
Association between self-reported walking speed and calcaneal stiffness index in postmenopausal Japanese women
Background: Osteoporosis and related fractures, a worldwide public health issue of growing concern, is characterized by compromised bone strength and an increased risk of fracture. Here we show an association between self-reported walking speed and bone mass among community-dwelling postmenopausal Japanese women aged 50 years and older. Design; cross-sectional study: Setting and Participants; The survey population included 1008 postmenopausal women 50?92 years of age residing in rural communities. Methods: Self-reported walking speed was ascertained by asking the participants: “Is your walking speed faster than others of the same age and sex?” to which participants responded “yes (faster)” or “no (moderate/slower).” Calcaneal stiffness index was measured. Results: Women with a faster self-reported walking speed were younger and had a lower BMI, higher stiffness index, and higher grip strength than women with a slower walking speed. Multiple linear regression analysis adjusted for age, BMI, grip strength, comorbidity, current smoking, and alcohol drinking status showed a significant association between faster self-reported walking speed and higher calcaneal stiffness index (p < 0.001). Conclusions: Our findings suggest that questionnaires of walking speed may be useful for predicting bone mass and that a fast self-reported walking may benefit bone health in postmenopausal women
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