Photonic-crystal nano-photodetector with ultrasmall capacitance for on-chip light-to-voltage conversion without an amplifier

The power consumption of a conventional photoreceiver is dominated by that of the electric amplifier connected to the photodetector (PD). An ultralow-capacitance PD can overcome this limitation, because it can generate sufficiently large voltage without an amplifier when combined with a high-impedance load. In this work, we demonstrate an ultracompact InGaAs PD based on a photonic crystal waveguide with a length of only 1.7 μm and a capacitance of less than 1 fF. Despite the small size of the device, a high responsivity of 1 A/W and a clear 40 Gbit/s eye diagram are observed, overcoming the conventional trade-off between size and responsivity. A resistor-loaded PD was actually fabricated for light-to-voltage conversion, and a kilo-volt/watt efficiency with a gigahertz bandwidth even without amplifiers was measured with an electro-optic probe. Combined experimental and theoretical results reveal that a bandwidth in excess of 10 GHz can be expected, leading to an ultralow energy consumption of less than 1 fJ/bit for the photoreceiver. Amplifier-less PDs with attractive performance levels are therefore feasible and a step toward a densely integrated photonic network/processor on a chip

Firm's reduction of greenhouse gas emissions and economic performance: analyzing effects through demand and productivity

This paper analyzes how a firmfs reduction of its greenhouse gas (GHG) emissions affects its economic performance. The theoretical model used is derived from the Cobb-Douglas production function and the inverse demand function, and predicts that in reducing its GHG emissions, a firm will increase its value added because it promotes an increase in demand for its output and improves its productivity. The estimation results, using data on Japanese manufacturing firms, suggest that the reduction of GHG emissions increases a firmfs economic performance only through an increase in demand. Thus, firms can improve their overall economic performance because increased demand accompanies their reduction of GHG emissions, even if they cannot achieve this through an improvement in productivity, as estimates here support the traditional view that reducing GHG emissions imposes additional costs on firms.Reduction of greenhouse gas emissions, Economic performance, Increase in demand, Improvement in productivity, Instrumental variables model

3次元再構成を用いた非骨性距踵骨癒合症の形態学的分析

Background: Resection of talocalcaneal coalitions has generally involved osseous coalitions. We attempted to evaluate the morphology of nonosseous talocalcaneal coalitions. This study aimed to investigate if the calcaneal articular surface area of feet with talocalcaneal coalitions is different than that of normal feet. Methods: Twenty nonosseous talocalcaneal coalition cases with analyzable computed tomography (CT) scans were compared to 20 control cases. Three-dimensional models of the talus and calcaneus were constructed, and the surface areas of the posterior facet (SPF), whole talocalcaneal joint of the calcaneus (SWJ), and coalition site (SCS) of each 3D-CT model were measured. "Calibrated" values of the 2 groups were created to adjust for relative size of the tali and then compared. The preoperative and postoperative AOFAS Ankle-Hindfoot scale was calculated for 9 cases that had undergone single coalition resection. Results: The calibrated SPF and SWJ were significantly greater in the coalition group than in the control group (40% and 12%, respectively). No significant difference was detected between the calibrated (SWJ - SCS) value of the coalition group and the calibrated SWJ value of the control group. The AOFAS scale was improved postoperatively in all 9 cases analyzed. Conclusion: The calcaneal articular surface of nonosseous talocalcaneal coalition feet in our series was larger than that of the normal feet. This study indicates that the total calcaneal articular surface after coalition resection may be comparable to the calcaneal articular surface of normal feet. We suggest that the indication for coalition resection be reconsidered for nonosseous coalition. Level of evidence: Level III, retrospective comparative study.博士（医学）・甲第815号・令和4年3月15日© The Author(s) 2021. Creative Commons Non Commercial CC BY-NC: This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/ open-access-at-sage)

Reinforcement learning accelerated by using state transition model with robotic applications

金沢大学工学部This paper discusses a method to accelerate reinforcement learning. Firstly defined is a concept that reduces the state space conserving policy. An algorithm is then given that calculates the optimal cost-to-go and the optimal policy in the reduced space from those in the original space. Using the reduced state space, learning convergence is accelerated. Its usefulness for both DP (dynamic programing) iteration and Q-learning are compared through a maze example. The convergence of the optimal cost-to-go in the original state space needs approximately N or more times as long as that in the reduced state space, where N is a ratio of the state number of the original space to the reduced space. The acceleration effect for Q-learning is more remarkable than that for the DP iteration. The proposed technique is also applied to a robot manipulator working for a peg-in-hole task with geometric constraints. The state space reduction can be considered as a model of the change of observation, i.e., one of cognitive actions. The obtained results explain that the change of observation is reasonable in terms of learning efficiency

状態遷移モデルを持つ強化学習における政策信頼性を考慮した学習効率化

取得学位：博士(工学)，学位授与番号：博甲第870号，学位授与年月日：平成19年3月22

Interleukin 17A plays a role in lipopolysaccharide/d-galactosamine–induced fulminant hepatic injury in mice

AbstractBackgroundLipopolysaccharide/d-galactosamine (LPS/GalN)–induced hepatic injury is an experimental model of fulminant hepatic failure in which tumor necrosis factor alpha (TNF-α) plays a pivotal role. Moreover, it was reported from our laboratory that interleukin (IL) 17A enhanced production of TNF-α by the Kupffer cell.ObjectiveThe purpose of this study was to determine the role of IL-17A in LPS/GalN-induced hepatic injury in mice.MethodsLPS/GalN was injected into three mouse models: wild-type (WT) mice, IL-17A knockout (KO) mice, or IL-17A KO mice treated with recombinant mouse (rm) IL-17A homodimer (KO + rmIL-17A). Survival was assessed for 24 h after LPS/GalN injection, and histopathologic findings were evaluated at various time points after LPS/GalN injection for neutrophil and apoptosis markers. After LPS/GalN injection, expression of the inflammatory mediators TNF-α, IL-6, monocyte chemotactic protein 1, IL-17A, high-mobility group box 1, and soluble intercellular adhesion molecule 1 was assessed in serum by enzyme-linked immunosorbent assay.ResultsSurvival was higher in KO mice compared with WT mice after LPS/GalN injection. However, in KO + rmIL-17A mice, mortality was not significantly different compared to the other groups. Neutrophil infiltration and apoptosis were significantly greater in WT mice than KO mice. Furthermore, serum alanine aminotransferase, serum TNF-α, monocyte chemotactic protein 1, IL-17A, high-mobility group box 1, and soluble intercellular adhesion molecule 1 levels were also significantly greater in WT mice than KO mice. In KO + rmIL-17A mice, these levels were similar to those in WT mice.ConclusionsIL-17A is a key regulator in hepatic injury caused by neutrophil-induced inflammatory responses after LPS/GalN injection

Decomposition analysis of air pollution abatement in China: Empirical study for ten industrial sectors from 1998 to 2009

This study analyzes air pollutant substances management in Chinese industrial sectors from 1998 to 2009. Decomposition analysis applying the logarithmic mean divisia index is used to analyze changes in air pollutant substances emissions by the following five factors: coal pollution intensity (CPI), end-of-pipe treatment (EOP), energy mix (EM), productive efficiency change (EFF), and production scale changes (PSC). We focus on the three pollutants which are sulfur dioxide (SO2), dust substance, and soot substance. We clarify SO2 emissions from Chinese industrial sectors have increased because of the increase in the production scale. However, the inducing EOP equipment and improvements in energy efficiency have prevented an increase in SO2 emissions commensurate with the production increasing. Second, soot emissions were successfully reduced and controlled in all industries except the steel industry between 1998 and 2009, even though the production scale expanded for these industries. This reduction is achieved because of improvements in the EOP equipment technology and in energy efficiency. Finally, dust emissions decreased by nearly 65% between 1998 and 2009 in the Chinese industrial sectors. This successful emissions reduction was achieved by implementing EOP and pollution prevention activities during the production processes, especially in the cement industry. We clarify that pollution prevention effect in cement industry is mainly caused by production technological development rather than scale merit

Changes in Environmentally Sensitive Productivity and Technological Modernization in China’s Iron and Steel Industry in the 1990s

Technological modernization is widely believed to contribute positively both to economic development and to environmental and resource conservation, through productivity improvements and strengthening of business competitiveness. However, this may not always be true, particularly in the short term, as it requires substantial investments and may impose financial burdens on firms undertaking such investments. This study empirically examines the effects of technological modernization in China’s iron and steel industry in the 1990s on conventional economic productivity (CEP) and environmentally sensitive productivities (ESPs). We employ a directional distance function that can handle multiple inputs and outputs to compute relative production efficiencies. We apply these models to the data covering 27 iron and steel firms in China between 1990 and 1999—a period when the Chinese iron and steel industry modernized rapidly. We find that ESPs have continuously improved, even in the period when the CEP declined