311 research outputs found
Block spin transformation on the dual lattice and monopole action
To find a perfect lattice action in terms of monopole action on the dual
lattice, we performed simulations of a monopole effective action obtained
numerically from vacuum configurations in SU(2) QCD. Although the Polyakov loop
behavior near is well reproduced by the action, a small but repulsive
term is needed in addition to get the string tension correctly. It is reported
also a monopole effective action in QCD which is expressed by one kind
of monopole currents.Comment: 4pages (4 figures), Latex, Contribution to Lattice 9
Three topics of monopole dynamics in abelian projected QCD
Three topics about monopole dynamics after abelian projection are reported.
The first is the new and detailed analyses of monopole action obtained
after the block-spin transformation on the dual lattice. The
dependence for all couplings are well fitted with a universal curve. The
distance dependence of the couplings is well reproduced by a massive propagator
with the mass in unit of . The second is the monopole action
recently obtained. The third is new interesting gauges showing abelian and
monopole dominances as in the maximally abelian gauge.Comment: Talk presented at LATTICE96(topology), 4 Pages, 7 eps figure
Monopole action and monopole condensation in SU(3) lattice QCD
Effective monopole actions for various extended monopoles are derived from
vacuum configurations after abelian projection in the maximally abelian gauge
in and lattice QCD. The actions obtained appear to be
independent of the lattice volume adopted. At zero temperature, monopole
condensation is seen to occur from energy-entropy balance in the strong
coupling region.
Larger is included in the monopole condensed phase as more extended
monopoles are considered. The scaling seen in the case is not yet
observed. The renormalization flow diagram suggests the existence of an
infrared fixed point. A hysteresis behavior is seen around the critical
temperature in the case of the action.Comment: 22 pages, latex, 10 figure
Poly(A)-Specific Ribonuclease Mediates 3′-End Trimming of Argonaute2-Cleaved Precursor MicroRNAs
SummaryMicroRNAs (miRNAs) are typically generated as ∼22-nucleotide double-stranded RNAs via the processing of precursor hairpins by the ribonuclease III enzyme Dicer, after which they are loaded into Argonaute (Ago) proteins to form an RNA-induced silencing complex (RISC). However, the biogenesis of miR-451, an erythropoietic miRNA conserved in vertebrates, occurs independently of Dicer and instead requires cleavage of the 3′ arm of the pre-miR-451 precursor hairpin by Ago2. The 3′ end of the Ago2-cleaved pre-miR-451 intermediate is then trimmed to the mature length by an unknown nuclease. Here, using a classical chromatographic approach, we identified poly(A)-specific ribonuclease (PARN) as the enzyme responsible for the 3′–5′ exonucleolytic trimming of Ago2-cleaved pre-miR-451. Surprisingly, our data show that trimming of Ago2-cleaved precursor miRNAs is not essential for target silencing, indicating that RISC is functional with miRNAs longer than the mature length. Our findings define the maturation step in the miRNA biogenesis pathway that depends on Ago2-mediated cleavage
Inner membrane YfgM–PpiD heterodimer acts as a functional unit that associates with the SecY/E/G translocon and promotes protein translocation
PpiD and YfgM are inner membrane proteins that are both composed of an N-terminal transmembrane segment and a C-terminal periplasmic domain. Escherichia coli YfgM and PpiD form a stable complex that interacts with the SecY/E/G (Sec) translocon, a channel that allows protein translocation across the cytoplasmic membrane. Although PpiD is known to function in protein translocation, the functional significance of PpiD-YfgM complex formation as well as the molecular mechanisms of PpiD-YfgM and PpiD/YfgM- Sec translocon interactions remain unclear. Here, we conducted genetic and biochemical studies using yfgM and ppiD mutants and demonstrated that a lack of YfgM caused partial PpiD degradation at its C-terminal region and hindered the membrane translocation of VemP, a Vibrio secretory protein in both Escherichia coli and Vibrio alginolyticus. While ppiD disruption also impaired VemP translocation, we found that the yfgM and ppiD double deletion exhibited no additive or synergistic effects. Together, these results strongly suggest that both PpiD and YfgM are required for efficient VemP translocation. Furthermore, our site-directed in vivo photo-crosslinking analysis revealed that the tetratricopeptide repeat domain of YfgM and a conserved structural domain (NC domain) in PpiD interact with each other and that YfgM, like PpiD, directly interacts with the SecG translocon subunit. Crosslinking analysis also suggested that PpiD/YfgM complex formation is required for these proteins to interact with SecG. In summary, we propose that PpiD and YfgM form a functional unit that stimulates protein translocation by facilitating proper interactions with the Sec translocon
Delayed Follow-up Visits and Thyrotropin Among Patients With Levothyroxine During the COVID-19 Pandemic
Context: The indirect effects of the COVID-19 pandemic on clinical practice have received great attention, but evidence regarding thyroid disease management is lacking. Objective: We aimed to investigate the association between delayed follow-up visits during the pandemic and their serum thyrotropin (TSH) levels among patients being treated with levothyroxine. Methods: This study included 25 361 patients who made a follow-up visit as scheduled (n = 9063) or a delayed follow-up visit ( 4.5 mIU/L, aRR [95% CI] = 1.72 [1.60-1.85]; and TSH > 10 mIU/L, aRR [95% CI] = 2.38 [2.16-2.62]). Conclusion: A delayed follow-up visit during the COVID-19 pandemic was associated with less well-controlled TSH among patients with levothyroxine
Early expression of serum CCL8 closely correlates to non-relapse mortality after allogeneic hematopoietic stem cell transplantation
To explore the role of Chemokine (C-C motif) ligand 8 (CCL8) as a potential biomarker for acute graft-versus-host disease (aGVHD), we retrospectively analyzed the sera and clinical course of 31 patients with grade II?IV aGVHD. No deaths occurred in the ten patients with serum CCL8 concentrations less than 213 pg/mL, whereas 11 of the 21 patients with more than 213 pg/mL died within 180 days post-transplantation. This landmark analysis revealed a significantly lower urvival rate of patients with a CCL8 serum concentration greater than 213 pg/mL. Thus, elevated serum CCL8 concentration before day 100 post-transplantation may predict aGVHD prognosi
Development of a dual phantom technique for measuring the fast neutron component of dose in boron neutron capture therapy.
[Purpose]: Research and development of various accelerator-based irradiation systems for boron neutroncapture therapy (BNCT) is underway throughout the world. Many of these systems are nearing or have started clinical trials. Before the start of treatment with BNCT, the relative biological effectiveness (RBE) for the fast neutrons (over 10 keV) incident to the irradiation field must be estimated. Measurements of RBE are typically performed by biological experiments with a phantom. Although the dose deposition due to secondary gamma rays is dominant, the relative contributions of thermal neutrons (below 0.5 eV) and fast neutrons are virtually equivalent under typical irradiationconditions in a water and/or acrylic phantom. Uniform contributions to the dose deposited from thermal and fast neutrons are based in part on relatively inaccurate dose information for fastneutrons. This study sought to improve the accuracy in the dose estimation for fast neutrons by using two phantoms made of different materials in which the dose components can be separated according to differences in the interaction cross sections. The development of a “dual phantom technique” for measuring the fast neutron component of dose is reported.
[Methods]: One phantom was filled with pure water. The other phantom was filled with a water solution of lithiumhydroxide (LiOH) capitalizing on the absorbing characteristics of lithium-6 (Li-6) for thermal neutrons.Monte Carlo simulations were used to determine the ideal mixing ratio of Li-6 in LiOH solution.Changes in the depth dose distributions for each respective dose component along the central beam axis were used to assess the LiOH concentration at the 0, 0.001, 0.01, 0.1, 1, and 10 wt. % levels. Simulations were also performed with the phantom filled with 10 wt. % [6]LiOH solution for 95%-enriched Li-6. A phantom was constructed containing 10 wt. % [6]LiOH solution based on the simulation results. Experimental characterization of the depth dose distributions of the neutron andgamma-ray components along the central axis was performed at Heavy Water Neutron IrradiationFacility installed at Kyoto University Reactor using activation foils and thermoluminescent dosimeters, respectively. [Results]: Simulation results demonstrated that the absorbing effect for thermal neutrons occurred when the LiOH concentration was over 1%. The most effective Li-6 concentration was determined to be enriched [6]LiOH with a solubility approaching its upper limit. Experiments confirmed that the thermalneutron flux and secondary gamma-ray dose rate decreased substantially; however, the fastneutron flux and primary gamma-ray dose rate were hardly affected in the 10%-[6]LiOH phantom. It was confirmed that the dose contribution of fast neutrons is improved from approximately 10% in the pure water phantom to approximately 50% in the 10%-[6]LiOH phantom. [Conclusions]: The dual phantom technique using the combination of a pure water phantom and a 10%-[6]LiOH phantom developed in this work provides an effective method for dose estimation of the fast neutroncomponent in BNCT. Improvement in the accuracy achieved with the proposed technique results in improved RBE estimation for biological experiments and clinical practice
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