Mie University

Subanesthetic doses of ketamine, a non-competitive N-methyl-D-aspartate receptor (NMDAR) antagonist, produce rapid and robust antidepressant effects in patients with treatment-resistant depression (TRD). However, after a single administration, the therapeutic benefit is short-lived, and strategies to maintain its efficacy remain unclear. This study focused on the glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), whose activation is known to be a key effector for the action of ketamine. Thus, we developed a novel positive allosteric modulator of AMPAR (K-4) with potential antidepressant-like effects. In Wistar Kyoto rats, a model of TRD, K-4 produced a more sustained antidepressant-like effect than ketamine. Bulk RNA sequencing analysis revealed that K-4-treated rats showed lower expression of NADPH-oxidase-1 (NOX-1) in the medial prefrontal cortex (mPFC) than in ketamine-treated rats. Furthermore, simultaneous administration of a NOX-1 inhibitor with ketamine prolonged the antidepressant-like effect and reduced burst firing in the lateral habenula (LHb). Similarly, short hairpin RNA knockdown of NOX-1 in the mPFC sustained the antidepressant-like effects of ketamine and suppressed LHb bursting activity. These results indicate that NOX-1 suppression prolongs the antidepressant-like effect of ketamine and represents a promising target for maintenance strategies in TRD.

This study systematically examines the robustness of the Akaike Information Criterion (AIC) in determining the optimal order (p) of an autoregressive (AR) model applied to the RR interval time series of the PhysioNet healthy subject database. The AR approach is widely used to estimate the power spectral density (PSD) of heart rate variability (HRV), and accurate order selection is essential for model stability and reliable spectral estimation. Although the AIC is designed to balance model fit and complexity, it suffers from the problem of arbitrary model selection. This study provides a quantitative robustness analysis of information-criterion-based AR order selection under controlled expansion of the search space. Specifically, we investigated the behavior of the AIC using the PhysioNet database (N = 1257) under conditions where the maximum search order was set to an excessively high value (p = 50), far exceeding the commonly recommended range. Our analysis suggested that the AR model began to capture subtle noise and nonstationary components rather than the intrinsic HRV structure, leading to overfitting and excessive order selection, resulting in false peaks in the PSD and reduced robustness. In conclusion, order decisions based solely on information criteria such as the AIC become unstable when the search range is too large. To ensure robustness, it is recommended to complement the AIC with more stringent criteria such as the Bayesian Information Criterion (BIC) or Final Prediction Error (FPE), in addition to the traditional maximum order restriction.

Probabilistic precipitation, such as the 100-year rainfall, is widely used as the design storm for planning flood control structures. However, due to climate change, the return periods estimated 50 years ago are no longer valid. This shift necessitates a fundamental reconsideration of how we determine design levels for construction. In other words, there is an urgent need for more sophisticated methodologies capable of handling non-stationary precipitation data.To address these challenges, we present two key topics:In Japan, the national and local governments have issued guidelines suggesting that future extreme rainfall intensities can be estimated by multiplying present-day values by a change factor of 1.1 to 1.15, assuming a 2.0°C increase in global temperature. While these guidelines tend to treat the change factor as largely uniform across regions for practical simplicity, we contend that it should be estimated with greater geographical precision. Consequently, we estimated the change factors specifically for Mie Prefecture in central Japan. Our results demonstrate that even within a single prefecture, the factor varies significantly depending on the specific location.We have been developing a novel approach to estimate future 100-year precipitation levels through multivariate analysis. The details of this methodology and our findings will be presented in our poster session.

To fabricate deep-ultraviolet (DUV) LEDs with high efficiency, the crystallinity of AlGaN must be improved, which is strongly influenced by the quality of the underlying AlN template. Face-to-face annealed sputter-deposited AlN templates (FFA Sp-AlN) on sapphire substrates have achieved screw and edge threading dislocation densities (TDDs) as low as 10⁴cm⁻² and 10⁷cm⁻², respectively. The reduction of TDDs in FFA Sp-AlN and the resulting surface flattening of AlₓGa₁₋ₓN layers grown on it play critical roles in enhancing the external quantum efficiency (EQE). Following MOVPE homoepitaxial AlN growth, the FFA Sp-AlN exhibits an atomically smooth surface morphology. The EQE of UV-C LEDs fabricated on FFA Sp-AlN increased as the TDDs decreased. A maximum EQE of 8.0% and output power of 6.6mW at a 20mA injection current were achieved, with a peak emission wavelength of 263nm. Furthermore, we successfully fabricated LEDs with emission wavelengths of 230nm and 236nm on FFA Sp-AlN templates.

症例は80歳代，男性．原発性胆汁性胆管炎による非代償性肝硬変，血小板減少と直腸静脈瘤で2年前より当院にて加療していた．部分的脾動脈塞栓術施行後から腹水貯留と門脈，脾静脈血栓を認め抗凝固療法を開始したが，肛門外突出型直腸静脈瘤（肛門静脈瘤）より出血を繰り返した．4次元CTによる血行動態評価では下腸間膜静脈から直腸静脈瘤に流入し，肛門突出部を経て内陰部静脈と内腸骨静脈に流出する複数の排血路が確認された．ダブルバルーン閉塞下に塞栓術を試みたが不成功で，肛門静脈瘤に対して目視下にn-butyl-2-cyanoacrylateを注入した．その後も肛門静脈瘤より再出血し，直腸静脈瘤に内視鏡的静脈瘤硬化療法を施行し止血し得た．現在，肛門静脈瘤に対する治療戦略は確立していない．今回，肛門外突出型直腸静脈瘤出血に対し，4次元CTで詳細な血行動態を把握後に，硬化療法で止血した症例を経験したため報告する．