361 research outputs found
First Nonperturbative Test of a Relativistic Heavy Quark Action in Quenched Lattice QCD
We perform a numerical test of a relativistic heavy quark(RHQ) action,
recently proposed by Tsukuba group, in quenched lattice QCD at
fm. With the use of the improvement parameters previously determined at
one-loop level for the RHQ action, we investigate a restoration of rotational
symmetry for heavy-heavy and heavy-light meson systems around the charm quark
mass. We focused on two quantities, the meson dispersion relation and the
pseudo-scalar meson decay constants. It is shown that the RHQ action
significantly reduces the discretization errors due to the charm quark mass. We
also calculate the S-state hyperfine splittings for the charmonium and
charmed-strange mesons and the meson decay constant. The remaining
discretization errors in the physical quantities are discussed.Comment: 21 pages, 16 figures. A reference and a comment added, a major
modification in appendix, several minor changes in the abstract and the main
text. Errors in affiliation are corrected. Version appeared in JHE
Charmed meson spectra and decay constants with one-loop improved relativistic heavy quark action
We calculate charmed meson spectra and decay constants in lattice QCD
employing one-loop improved heavy quark action and axial-vector
currents. In quenched simulations at fm with the plaquette gauge
action as well as a renormalization-group improved one, it is shown that the
deviation from the continuum dispersion relation and the violation of
space-time symmetry for the pseudoscalar meson decay constants are
substantially reduced, once the improvement is applied. Preliminary
results with two flavors of dynamical quarks are also presented.Comment: 3 pages, 4 figure, talk presented at Lattice2004(heavy), Fermilab,
June 21-26, 200
Relationship of Chinese Tungusic ethnic minorities with Okhotsk cultural people in regard to dental metric traits
We used crown measurements to analyze the anthropological characteristics of three Tungusic tribes, Ewenki, Hezhen, and Oroqen, residing in the Amur River basin of China. Previous findings suggest that Amur River basin populations were involved in the population structure of Tungusic people. We then compared our findings with those of individuals with a north Asian ethnic background to examine the distribution of those characteristics in north Asian Mongoloids (1). The total crown area was classified as Sinodont (2). A deviation diagram showed scant differences among Hezhen, Oroqen, and Okhotsk individuals, indicating the closeness of those populations (3). Q-mode correlation coefficients and 2-dimensional expression suggested that Tungusic individuals were the Central Asia type. Hezhen and Oroqen were plotted closer to Okhotsk cultural people, and closely related. Race mixture occurred among the Baikal, then spread from Lake Baikal and Central Asia from the south in the post-Neolithic Era, and the groups gradually diffused to the lower Amur region. Therefore, it is reasonable to conclude that a different degree of miscegenation occurred between the Baikal and Central Asian regions in the area from Lake Baikal to lower Amur in accordance with the geographical features
Oral health status: relationship to nutrient and food intake among 80âyearâold Japanese adults
Objectives The aim of this crossâsectional study was to investigate the relationship of oral health status defined on the basis of presence of posterior occluding pairs ( POP s) and adequacy of removable denture fit as determined by selfâreport to nutrient and food intake among older Japanese. Methods The subjects were 353 Japanese aged 80 years in 2008 and were classified into four groups according to the number of POP s, defined as pairs of occluding natural, restored, or fixed prosthetic postcanine teeth (range: 0â8) and removable denture status. The groups were: (i) good dentition ( n =  56; 8 POP s and no removable prosthesis), (ii) wellâfitting dentures ( n =  158; <8 POP s with selfâreported goodâfitting dentures), (iii) illâfitting dentures ( n =  70; <8 POP s with selfâreported illâfitting dentures), and (iv) compromised dentition ( n =  69; <8 POP s and no removable prosthesis). Multivariable analysis of the differences in nutrient and food intake outcome variables which were collected via validated food frequency questionnaire among the four oral health status groups was conducted using general linear models. Results Intake of multiple nutrients was significantly ( P <  0.05) lower in the group with illâfitting dentures or compromised dentition than in the good dentition group. Vegetable, fish, and shellfish consumption was significantly lower in the illâfitting dentures or compromised dentition groups. No significant differences were seen in dietary intake between the wellâfitting dentures and good dentition groups. Conclusions Dietary intake was poorer in those with selfâperceived illâfitting dentures or fewer POP s than among those having all POP s. Regular dental care to maintain intact dentition, as well as dental treatment to replace missing teeth and ensure adequate denture fit and function, may be important to the diet intake and subsequent nutritional status of older Japanese.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108691/1/cdoe12100.pd
Systemic and Ocular Determinants of Choroidal Structures on Optical Coherence Tomography of Eyes with Diabetes and Diabetic Retinopathy
Knowledgeof the choroidal structures in eyes with diabetes and diabetic retinopathy (DR) should provide information on the pathogenesis of DR. A prospective study was performed to determine the systemic and ocular factors that affect the choroidal structures in eyes with diabetes. Two-hundred consecutive diabetic subjects consisted of 160 treatment-naĂŻve patients with different stages of DR and 40 patients with proliferative DR with prior panretinal photocoagulation (PRP). All underwent blood and urine tests and enhanced depth imaging optical coherence tomography (EDI-OCT). The cross-sectional EDI-OCT images of the subfoveal choroid were binarized to measure the total choroidal area (TCA), luminal area, and stromal area. Multivariate regression analyses were performed to determine the systemic and ocular factors that were significantly correlated with the choroidal structures. The subfoveal choroidal thickness, TCA, luminal area, and stromal area were larger at more advanced stage of DR, and smaller in eyes with PRP than those without (Pâ<â0.001). The TCA and stromal area were significantly and positively correlated with the degree of albuminuria (Pâ=â0.034, Pâ=â0.025, respectively). The choroidal lumen and stroma may increase as the stages of DR progress and decrease after PRP. Albuminuria may be associated with the choroidal stromal edema
Effect of lifestyle on 6âyear periodontitis incidence or progression and tooth loss in older adults
AimTo evaluate the longitudinal association of combined healthy lifestyle factors with incidence or progression of periodontitis and tooth loss in older adults.Materials and methodsThis 6âyear study included 374 Japanese 70âyear olds with 7,157 teeth, from a source eligible baseline population of 554 individuals. Four lifestyle factorsâcigarette smoking, physical activity, relative weight, and dietary qualityâwere scored as healthy (1 point) or unhealthy (0 point). Adding the individual scores generated the âhealthy lifestyle scoreâ (0â4 points). Multilevel mixedâeffects logistic regression models were applied to evaluate toothâspecific associations between the baseline healthy lifestyle score and the incidence or progression of periodontitis (increase in clinical attachment loss â„3 mm) and tooth loss.ResultsAfter 6 years, 19.0% of the teeth exhibited periodontitis incidence or progression and 8.2% were lost. Compared with a healthy lifestyle score of 0â1 (least healthy), the highest score (4 points) was associated with a significantly lower toothâspecific risk of periodontitis (adjusted odds ratio = 0.32; 95% confidence interval: 0.16â0.62) and tooth loss (adjusted odds ratio = 0.42; 95% confidence interval: 0.23â0.77).ConclusionsSimultaneous adherence to multiple healthy lifestyle factors significantly lowers the risk of incidence or progression of periodontitis and tooth loss in older adults.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145573/1/jcpe12920_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145573/2/jcpe12920.pd
Two distinct prions in fatal familial insomnia and its sporadic form
Abstract
Fatal familial insomnia is a genetic prion disease, which is associated with the aspartic acid to asparagine substitution at codon 178 of the prion protein gene. Although the hallmark pathological feature is thalamic and olivary degeneration, there is a patient with an atypical fatal familial insomnia without the hallmark feature. The cause of the pathological variability is unclear. We analysed a Japanese fatal familial insomnia kindred and compared one atypical clinicopathological fatal familial insomnia phenotype case and typical fatal familial insomnia phenotype cases with transmission studies using multiple lines of knock-in mice and with protein misfolding cyclic amplification. We also analysed the transmissibility and the amplification properties of sporadic fatal insomnia. Transmission studies revealed that the typical fatal familial insomnia with thalamic and olivary degeneration showed successful transmission only using knock-in mice expressing humanâmouse chimeric prion protein gene. The atypical fatal familial insomnia with spongiform changes showed successful transmission only using knock-in mice expressing bank vole prion protein gene. Two sporadic fatal insomnia cases with thalamic and olivary degeneration showed the same transmissibility as the typical fatal familial insomnia phenotype. Interestingly, one sporadic fatal insomnia case with thalamic/olivary degeneration and spongiform changes showed transmissibility of both the typical and atypical fatal familial insomnia phenotypes. Protein misfolding cyclic amplification could amplify both typical fatal familial insomnia cases and sporadic fatal insomnia cases but not the atypical fatal familial insomnia phenotype or other sporadic CreutzfeldtâJakob disease subtypes. In addition to clinical findings and neuropathological features, the transmission properties and the amplification properties were different between the typical and atypical fatal familial insomnia phenotypes. It is suggested that two distinct prions were associated with the diversity in the fatal familial insomnia phenotype, and these two prions could also be detected in sporadic fatal insomnia
The bifurcation angle is associated with the progression of saccular aneurysms
The role of the bifurcation angle in progression of saccular intracranial aneurysms (sIAs) has been undetermined. We, therefore, assessed the association of bifurcation angles with aneurysm progression using a bifurcation-type aneurysm model in rats and anterior communicating artery aneurysms in a multicenter case-control study. Aneurysm progression was defined as growth byââ„â1 mm or rupture during observation, and controls as progression-free for 30 days in rats andââ„â36 months in humans. In the rat model, baseline bifurcation angles were significantly wider in progressive aneurysms than in stable ones. In the case-control study, 27 and 65 patients were enrolled in the progression and control groups. Inter-observer agreement for the presence or absence of the growth was excellent (Îș coefficient, 0.82; 95% CI, 0.61-1.0). Multivariate logistic regression analysis showed that wider baseline bifurcation angles were significantly associated with subsequent progressions. The odds ratio for the progression of the second (145°-179°) or third (180°-274°) tertiles compared to the first tertile (46°-143°) were 5.5 (95% CI, 1.3-35). Besides, the bifurcation angle was positively correlated with the size of aneurysms (Spearman's rho, 0.39; Pâ=â0.00014). The present study suggests the usefulness of the bifurcation angle for predicting the progression of sIAs
A novel in vitro survival assay of small intestinal stem cells after exposure to ionizing radiation
The microcolony assay developed by Withers and Elkind has been a gold standard to assess the surviving fraction of small intestinal stem cells after exposure to high (?8 Gy) doses of ionizing radiation (IR), but is not applicable in cases of exposure to lower doses. Here, we developed a novel in vitro assay that enables assessment of the surviving fraction of small intestinal stem cells after exposure to lower IR doses. The assay includes in vitro culture of small intestinal stem cells, which allows the stem cells to develop into epithelial organoids containing all four differentiated cell types of the small intestine. We used Lgr5-EGFP-IRES-CreERT2/ROSA26-tdTomato mice to identify Lgr5+ stem cells and their progeny. Enzymatically dissociated single crypt cells from the duodenum and jejunum of mice were irradiated with 7.25, 29, 101, 304, 1000, 2000 and 4000 mGy of X-rays immediately after plating, and the number of organoids was counted on Day 12. Organoid-forming efficiency of irradiated cells relative to that of unirradiated controls was defined as the surviving fraction of stem cells. We observed a significant decrease in the surviving fraction of stem cells at ?1000 mGy. Moreover, fluorescence-activated cell sorting analyses and passage of the organoids revealed that proliferation of stem cells surviving IR is significantly potentiated. Together, the present study demonstrates that the in vitro assay is useful for quantitatively assessing the surviving fraction of small intestinal stem cells after exposure to lower doses of IR as compared with previous examinations using the microcolony assay
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