Deep low-frequency tremors as a proxy for slip monitoring at plate interface

金沢大学理工研究域自然システム学系We propose a new method to monitor slip at the plate interface using non-volcanic deep-low frequency (DLF) tremors. We assume that a DLF tremor is the superposition of frequently excited intermittent events, meaning that the envelope of the reduced displacement of the DLF tremor provides an apparent moment rate function. We estimate a conversion factor from the apparent moment to the seismic moment with an assumption that a total size of DLF tremors of an episode is proportional to the size of corresponding slow slip event (SSE). The cumulative seismic moment estimated by DLF tremors is consistent with that estimated from geodetic methods and provides appropriate slip and slip rate at the plate interface. This proves our assumptions and demonstrates that DLF tremors are useful tool for realtime monitoring of the slip at the plate interface. Copyright 2008 by the American Geophysical Union

Scaling relationship between the duration and the amplitude of non-volcanic deep low-frequency tremors

金沢大学大学院自然科学研究科自然計測金沢大学理学部We investigate a duration-amplitude relation of non-volcanic deep low-frequency (DLF) tremors in the Tokai region, southwest Japan, to constrain the source process of the tremors. We apply two models to the distribution, one is an exponential model as a scale bound distribution and the other a power law model as a scale invariant distribution. The exponential model shows a better fit to the duration-amplitude distribution of the tremors than a power law model, implying that the DLF tremors are caused by a scale-bound source process. The source process of the DLF tremors, therefore, differs from those for earthquakes. We suggest that the non-volcanic DLF tremor is possibly caused by a fixed source dimension with variable excess pressure of fluid or variable stress drop. Copyright 2007 by the American Geophysical Union

Identification and functional characterization of an N-terminal oligomerization domain for polycystin-2*

Autosomal dominant polycystic kidney disease (ADPKD), the most common inherited cause of kidney failure, is caused by mutations in either PKD1 (85%) or PKD2 (15%). The PKD2 protein, polycystin-2 (PC2 or TRPP2), is a member of the transient receptor potential (TRP) superfamily and functions as a non-selective calcium channel. PC2 has been found to form oligomers in native tissues suggesting that it may form functional homo- or heterotetramers with other subunits, similar to other TRP channels. Our experiments unexpectedly revealed that PC2 mutant proteins lacking the known C-terminal dimerization domain were still able to form oligomers and co-immunoprecipitate full-length PC2, implying the possible existence of a proximal dimerization domain. Using yeast two-hybrid and biochemical assays, we have mapped an alternative dimerization domain to the N terminus of PC2 (NT2-1-223, L224X). Functional characterization of this domain demonstrated that it was sufficient to induce cyst formation in zebrafish embryos and inhibit PC2 surface currents in mIMCD3 cells probably by a dominant-negative mechanism. In summary, we propose a model for PC2 assembly as a functional tetramer which depends on both C- and N-terminal dimerization domains. These results have significant implications for our understanding of PC2 function and disease pathogenesis in ADPKD and provide a new strategy for studying PC2 function

Strong exciton‐photon coupling and its polarization dependence in a metal‐mirror microcavity with oriented PIC J‐aggregates

We present a study of strong exciton-photon coupling and its dependence on incident light polarization in a metal-metal mirror microcavity containing PIC J-aggregates. Rabi-splitting energies between upper and lower polariton branches are estimated as 94 meV and 69 meV for s- and p-polarized incident light, respectively. These large values are due to large oscillator strength of Frenkel excitons in the PIC J-aggregates and strong confinement of light attributed to the metallic microcavity as well. As for the effective thickness of the active layer for s-polarized light, a good agreement is obtained between Lfiteff = 201 nm deduced from the experimental data and Lcalceff = 207 nm calculated from the summation of the measured thickness of active layer with the estimated penetration depths into silver mirrors. We also discuss the difference in the polarization dependences of Rabi-splitting energy, quantitatively. It is concluded that the polarization dependence is mainly due to an alignment of the J-aggregates in the active layer and is not affected so much by anisotropy of the penetration depths into the silver mirrors

Geriatric nutritional risk index predicts all‐cause deaths in heart failure with preserved ejection fraction

AimsThe objective of the study was to evaluate whether the geriatric nutritional risk index (GNRI) at discharge may be helpful in predicting the long‐term prognosis of patients hospitalized with heart failure (HF) with preserved ejection fraction (HFpEF, left ventricular ejection fraction ≥50%), a common HF phenotype in the elderly.Methods and resultsOverall, 110 elderly HFpEF patients (≥65 years) from the Ibaraki Cardiovascular Assessment Study‐HF (n = 838) were enrolled. The mean age was 78.5 ± 7.2 years, and male patients accounted for 53.6% (n = 59). All‐cause mortality was compared between the low GNRI (<92) with moderate or severe nutritional risk group and the high GNRI (≥92) with no or low nutritional risk group. Cox proportional hazard regression models were constructed to evaluate the influence of the GNRI on all‐cause death with the following covariates using forward stepwise selection: age, sex, nutritional status based on the GNRI as a categorical variable, history of HF hospitalization, haemoglobin level, estimated glomerular filtration rate, log brain natriuretic peptide levels (logBNP), history of hypertension, log C‐reactive protein levels, left ventricular ejection fraction, left ventricular mass index, and the New York Heart Association functional classification (I/II or III class). The prognostic value of the GNRI was compared with that of serum albumin using C‐statistics. The GNRI was added to the logBNP, serum albumin or the body mass index was added to the logBNP, and the C‐statistic was compared using DeLong\u27s test. Cox regression analysis revealed that age and a low GNRI were independent predictors of all‐cause death (P < 0.05, n = 103; hazard ratio = 1.095, 95% confidence interval = 1.031–1.163, for age, and hazard ratio = 3.075, 95% confidence interval = 1.244–7.600, for the GNRI). DeLong\u27s test for the two correlated receiver operating characteristic curves [area under the receiver operating characteristic curve (AUROC) of serum albumin, 0.71; AUROC of the GNRI, 0.75] demonstrated significant differences between the groups (P = 0.038). Adding the GNRI to the logBNP increased the AUROC for all‐cause death significantly (0.71 and 0.80, respectively; P = 0.040, n = 105). The addition of serum albumin or the body mass index to the logBNP did not significantly increase the AUROC for all‐cause death (P = 0.082 and P = 0.29, respectively).ConclusionsNutritional screening using the GNRI at discharge is helpful to predict the long‐term prognosis of elderly HFpEF patients