複雑骨格天然物のモジュール型生合成マシナリーの機能解析と再設計

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 阿部 郁朗, 東京大学教授 大和田 智彦, 東京大学教授 井上 将行, 東京大学教授 清水 敏之, 東京大学准教授 花岡 健二郎University of Tokyo(東京大学

Differential recruitment of brain networks in single-digit addition and multiplication: Evidence from EEG oscillations in theta and lower alpha bands

Abstract Previous neuroimaging research investigating dissociation between single-digit addition and multiplication has suggested that the former placed more reliance on the visuo-spatial processing whereas the latter on the verbal processing. However, there has been little exploration into the disassociation in spatio-temporal dynamics of the oscillatory brain activity in specific frequency bands during the two arithmetic operations. To address this issue, the electroencephalogram (EEG) data were recorded from 19 participants engaged in a delayed verification arithmetic task. By analyzing oscillatory EEG activity in theta (5–7 Hz) and lower alpha frequency (9–10 Hz) bands, we found different patterns of oscillatory brain activity between single-digit addition and multiplication during the early processing stage (0–400 ms post-operand onset). Experiment results in this study showed a larger phasic increase of theta-band power for addition than for multiplication in the midline and the right frontal and central regions during the operator and operands presentation intervals, which was extended to the right parietal and the right occipito-temporal regions during the interval immediately after the operands presentation. In contrast, during multiplication higher phase-locking in lower alpha band was evident in the centro-parietal regions during the operator presentation, which was extended to the left fronto-central and anterior regions during the operands presentation. Besides, we found stronger theta phase synchrony between the parietal areas and the right occipital areas for single-digit addition than for multiplication during operands encoding. These findings of oscillatory brain activity extend the previous observations on functional dissociation between the two arithmetic operations

The effect of acupuncture at the Taiyang acupoint on visual function and EEG microstates in myopia

ObjectiveAcupuncture has certain effects to improve myopia visual function, but its neural mechanism is unclear. In this study, we acupunctured at the right Taiyang acupoint of myopic patients to analyze the effects of acupuncture on visual function and electroencephalographic activity and to investigate the correlation between improvements in visual function and changes in the brain.MethodsIn this study, a total of 18 myopic patients were recruited. The contrast sensitivity (CS) of the subjects was examined before and after acupuncture, and electroencephalography (EEG) data of the entire acupuncture process were recorded.ResultsThe study found that compared with before acupuncture, the CS of both eyes in myopic patients at each spatial frequency was increased after acupuncture; compared with the resting state, the contribution of microstate C was decreased during the post-acupuncture state, and the transition probability between microstate A and microstate C was reduced; in addition, the contribution of microstate C was negatively correlated with CS at both 12 and 18 cpd.ConclusionThe contrast sensitivity of myopic patients was improved after acupuncture at the Taiyang acupoint (20 min), which may be related to microstate C

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

A Study of Innovation in the Clean Energy Sector: Patent Trend Analysis

39 pagesDo most countries still stick to the guidelines to alleviate global warming since the Paris Agreement in 2008, and how well do domestic policies contribute to this global mutual goal? One avenue to answer these questions is to examine patenting trends in the clean energy sector, which serve as a proxy for the innovation of clean technologies. Prior research has documented the economic benefits of policies that buttress the scientific research and innovation process, including in the context of environmental regulation. There are also recent studies analyzing the effect of the stringency of environmental regulation on innovation in the clean energy sector. This paper extends the patenting trend analysis in clean sectors with multiple variables to study the effect of the stringency of environmental regulation on patenting. Empirical models explore the effects of regulatory stringency using different time lags, as well as accounting for other factors that vary over countries and time. Although the results are mixed, comparisons across models indicate that standardized variables perform better than non-standardized variables after a country-fixed effect is included in the model. Moreover, the result shows that the stimulative effect of regulation on innovation occurs over relatively short time horizons up to a few years