2 + 1 flavor lattice QCD toward the physical point Aoki, S.; Ishikawa, K.-I.; Ishizuka, N. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
02/2009, Letnik:
79, Številka:
3
Journal Article
Recenzirano
Odprti dostop
We present the first results of the PACS-CS project which aims to simulate 2+1 flavor lattice QCD on the physical point with the nonperturbatively O(a)-improved Wilson quark action and the Iwasaki ...gauge action. Numerical simulations are carried out at {beta} = 1.9, corresponding to the lattice spacing of a = 0.0907(13) fm, on a 32{sup 3} x 64 lattice with the use of the domain-decomposed HMC algorithm to reduce the up-down quark mass. Further algorithmic improvements make possible the simulation whose up-down quark mass is as light as the physical value. The resulting pseudoscalar meson masses range from 702 MeV down to 156 MeV, which clearly exhibit the presence of chiral logarithms. An analysis of the pseudoscalar meson sector with SU(3) chiral perturbation theory reveals that the next-to-leading order corrections are large at the physical strange quark mass. In order to estimate the physical up-down quark mass, we employ the SU(2) chiral analysis expanding the strange quark contributions analytically around the physical strange quark mass. The SU(2) low energy constants T{sub 3} and T{sub 4} are comparable with the recent estimates by other lattice QCD calculations. We determine the physical point together with the lattice spacing employing m{sub {pi}}, m{sub K} and m{sub {Omega}} as input. The hadron spectrum extrapolated to the physical point shows an agreement with the experimental values at a few % level of statistical errors, albeit there remain possible cutoff effects. We also find that our results of f{sub {pi}}, f{sub K} and their ratio, where renormalization is carries out perturbatively at one loop, are compatible with the experimental values. For the physical quark masses we obtain m{sub ud}{sup MS{sup -}} and m{sub s}{sup MS{sup -}} extracted from the axial-vector Ward-Takahashi identity with the perturbative renormalization factors. We also briefly discuss the results for the static quark potential.
Summary
Background
Chronic rhinosinusitis with nasal polyps is generally characterized by local Th2 inflammation and is categorized into two subtypes in Japan: eosinophilic chronic rhinosinusitis ...(similar to chronic rhinosinusitis with nasal polyps in western countries) and non‐eosinophilic chronic rhinosinusitis (characterized by Th1‐dominant inflammation).
Objective
To investigate local IgE production and class switch recombination to IgE in these two subtypes of chronic rhinosinusitis with nasal polyps.
Methods
The identity of IgE‐positive cells was determined using double‐immunofluorescent staining for IgE and cell‐type‐specific molecular markers. To investigate the local class switch recombination to IgE and IgE synthesis in the mucosa, we performed real‐time polymerase chain reaction to examine the mRNA expression of Th2 cytokines and class‐switch‐related molecules, including IL‐4, IL‐5, IL‐13, ε germline gene transcripts, IgE mature transcript, IgG mature transcript, RAG1, RAG2 and activation‐induced cytidine deaminase in eosinophilic polyps, non‐eosinophilic polyps and controls.
Results
The concentrations of total IgE and number of IgE‐positive cells were significantly higher in the eosinophilic polyps compared with control and non‐eosinophilic polyps. IgE‐positive cells were predominantly mast cells in eosinophilic polyps and significantly correlated with the number of FcεR1‐positive cells in the subepithelial layer. IL‐5 and IL‐13 mRNA and ε germline gene transcripts expression levels were significantly higher in eosinophilic polyps compared with control and non‐eosinophilic polyps. In contrast, the number of plasma cells and the expression of IgG mature transcripts were increased in non‐eosinophilic polyps compared with eosinophilic polyps. RAG2 mRNA was significantly increased in both eosinophilic and non‐eosinophilic polyps compared with control mucosa.
Conclusion and Clinical Relevance
The current study suggests local class switching to IgE, production of IgE and IgE localization to the surface of mast cells in eosinophilic chronic rhinosinusitis in the Japanese population. The difference in the IgE‐related profiles between eosinophilic chronic rhinosinusitis and non‐eosinophilic chronic rhinosinusitis suggests heterogeneity in the pathogenesis of chronic rhinosinusitis with nasal polyps.
To investigate the clinical and radiological features to predict adhesion between vestibular schwannoma (VS) and brain tissue which is a critical risk factor for postoperative infarction and residual ...tumour.
One hundred and seven consecutive VS surgeries were analysed. After excluding cases without contrast-enhanced (CE) computed tomography (CT), Koos grades 1 and 2, and cases with incomplete clinical data, 44 patients were finally included in the study. Enhancement of the tumour capsule on the brainstem side on CE-CT was defined as the CE-CT rim sign, which was analysed along with clinical characteristics, including tumour adhesion and postoperative complications.
Eight patients exhibited CE-CT rim signs; 17 had tumour adhesions. Four patients had postoperative infarction at the ipsilateral middle cerebellar peduncle; 18 exhibited postoperative infarction and/or residual tumour at the middle cerebellar peduncle. The CE-CT rim sign significantly correlated with tumour adhesion, postoperative infarction, and postoperative infarction and/or residual tumour in the cerebellar peduncle. Univariate regression analysis revealed that the CE-CT rim sign significantly correlated with tumour adhesion (odds ratio OR 6.81, 95% confidence interval CI 1.18-39.25, p=0.032) and postoperative infarction and/or residual tumour at the cerebellar peduncle (OR 6.00, 95% CI 1.04-34.31, p=0.044).
The CE-CT rim sign was identified in 18.2% of patients with VS and significantly correlated with tumour adhesion and postoperative complications, such as postoperative infarction and residual tumour. This study highlights the importance of the preoperative CE-CT rim sign in VS, which is predictive of tumour adhesion and postoperative complications.
Our recent studies demonstrated that regional bone loss in the unloaded hind limbs of tail-suspended mice triggered pain-like behaviors due to the acidic environment in the bone induced by osteoclast ...activation. The aims of the present study were to examine whether TRPV1, ASIC and P2X (known as nociceptors) are expressed in bone, and whether the antagonists to those receptors affect the expression of osteoblast and osteoclast regulators, and prevent the triggering of not only pain-like behaviors but also high bone turnover conditions in tail-suspension model mice.
The hind limb-unloaded mice were subjected to tail suspension with the hind limbs elevated for 14days. The effects of the TRPV1, ASIC3, P2X2/3 antagonists on pain-like behaviors as assessed by the von Frey test, paw flick test and spontaneous pain scale; the expressions of TRPV1, ASICs, and P2X2 in the bone; and the effects of those antagonists on osteoblast and osteoclast regulators were examined. In addition, we evaluated the preventive effect of continuous treatment with a TRPV1 antagonist on the trigger for pain-like behavior and bone loss in tail-suspended mice.
Pain-like behaviors were significantly improved by the treatment with TRPV1, ASIC, P2X antagonists; TRPV1, ASICs and P2X were expressed in the bone tissues; and the antagonists to these receptors down-regulated the expression of osteoblast and osteoclast regulators in tail-suspended mice. In addition, continuous treatment with a TRPV1 antagonist during tail-suspension prevented the induction of pain-like behaviors and regional bone loss in the unloaded hind limbs.
We, therefore, believe that those receptor antagonists have a potential role in preventing the triggering of skeletal pain with associated regional bone metabolic disorder.
•Bone loss in tail-suspended mice was related to induction of pain-like behaviors.•TRPV1, ASIC and P2X, known as nociceptors, were expressed in bone.•Antagonist to TRPV1, ASIC and P2X improved pain-like behavior in tail-suspended mice.•Antagonist to TRPV1, ASIC and P2X inhibited expression of regulators of bone cells.•Treatment with TRPV1 antagonist prevented regional bone loss in unloaded hind limbs.
We are developing a new lattice QCD code set "Bridge++" aiming at extensible, readable, and portable workbench for QCD simulations, while keeping a high performance at the same time. Bridge++ covers ...conventional lattice actions and numerical algorithms. The code set is constructed in C++ with an object oriented programming. In this paper we describe fundamental ingredients of the code and the current status of development.
We investigate the charm quark system using the relativistic heavy quark action on 2+1 flavor PACS-CS configurations previously generated on 32{sup 3} x 64 lattice. The dynamical up, down, and ...strange quark masses are set to the physical values by using the technique of reweighting to shift the quark-hopping parameters from the values employed in the configuration generation. At the physical point, the lattice spacing equals a{sup -1} = 2.194(10) GeV and the spatial extent L = 2.88(1) fm. The charm quark mass is determined by the spin-averaged mass of the 1S charmonium state, from which we obtain m{sub charm}{sup M{bar S}} ({mu} = m{sub charm}{sup M{bar S}}) = 1.260(1)(6)(35) GeV, where the errors are due to our statistics, scale determination and renormalization factor. An additional systematic error from the heavy quark is of order {alpha}{sub s}{sup 2}f(m{sub Q}a)(a{Lambda}{sub QCD}), f(m{sub Q}a)(a{Lambda}{sub QCD}){sup 2}, which are estimated to be a percent level if the factor f(m{sub Q}a) analytic in m{sub Q}a is of order unity. Our results for the charmed and charmed-strange meson decay constants are f{sub D} = 226(6)(1)(5) MeV, f{sub D}{sub s} = 257(2)(1)(5) MeV, again up to the heavy quark errors of order {alpha}{sub s}{sup 2}f(m{sub Q}a)(a{Lambda}{sub QCD}), f(m{sub Q}a)(a{Lambda}{sub QCD}){sup 2}. Combined with the CLEO values for the leptonic decay widths, these values yield |V{sub cd}| = 0.205(6)(1)(5)(9), |V{sub cs}| = 1.00(1)(1)(3)(3), where the last error is because of the experimental uncertainty of the decay widths.
We study the equation of state in 2 + 1 flavor QCD with nonperturbatively improved Wilson quarks coupled with the renormalization group-improved Iwasaki glue. We apply the T-integration method to ...nonperturbatively calculate the equation of state by the fixed-scale approach. With the fixed-scale approach, we can purely vary the temperature on a line of constant physics without changing the system size and renormalization constants. Unlike the conventional fixed-Nt approach, it is easy to keep scaling violations small at low temperature in the fixed-scale approach. We study 2 + 1 flavor QCD at light quark mass corresponding to m sub(pi)/m sub(rho) Asymptotically = to 0.63, while the strange quark mass is chosen around the physical point. Although the light quark masses are still heavier than the physical values, our equation of state is roughly consistent with recent results with highly improved staggered quarks at large Nt.
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