One-Shot Machine Unlearning with Mnemonic Code

Deep learning has achieved significant improvements in accuracy and has been applied to various fields. With the spread of deep learning, a new problem has also emerged; deep learning models can sometimes have undesirable information from an ethical standpoint. This problem must be resolved if deep learning is to make sensitive decisions such as hiring and prison sentencing. Machine unlearning (MU) is the research area that responds to such demands. MU aims at forgetting about undesirable training data from a trained deep learning model. A naive MU approach is to re-train the whole model with the training data from which the undesirable data has been removed. However, re-training the whole model can take a huge amount of time and consumes significant computer resources. To make MU even more practical, a simple-yet-effective MU method is required. In this paper, we propose a one-shot MU method, which does not need additional training. To design one-shot MU, we add noise to the model parameters that are sensitive to undesirable information. In our proposed method, we use the Fisher information matrix (FIM) to estimate the sensitive model parameters. Training data were usually used to evaluate the FIM in existing methods. In contrast, we avoid the need to retain the training data for calculating the FIM by using class-specific synthetic signals called mnemonic code. Extensive experiments using artificial and natural datasets demonstrate that our method outperforms the existing methods.Comment: 14 pages, welcome coment

Revisiting Permutation Symmetry for Merging Models between Different Datasets

Model merging is a new approach to creating a new model by combining the weights of different trained models. Previous studies report that model merging works well for models trained on a single dataset with different random seeds, while model merging between different datasets is difficult. Merging knowledge from different datasets has practical significance, but it has not been well investigated. In this paper, we investigate the properties of merging models between different datasets. Through theoretical and empirical analyses, we find that the accuracy of the merged model decreases more significantly as the datasets diverge more and that the different loss landscapes for each dataset make model merging between different datasets difficult. We also show that merged models require datasets for merging in order to achieve a high accuracy. Furthermore, we show that condensed datasets created by dataset condensation can be used as substitutes for the original datasets when merging models. We conduct experiments for model merging between different datasets. When merging between MNIST and Fashion- MNIST models, the accuracy significantly improves by 28% using the dataset and 25% using the condensed dataset compared with not using the dataset.Comment: 18 pages; comments are welcom

Pex14p phosphorylation regulates peroxisome import

Peroxisomal matrix proteins are imported into peroxisomes via membrane-bound docking/translocation machinery. One central component of this machinery is Pex14p, a peroxisomal membrane protein involved in the docking of Pex5p, the receptor for peroxisome targeting signal type 1 (PTS1). Studies in several yeast species have shown that Pex14p is phosphorylated in vivo, whereas no function has been assigned to Pex14p phosphorylation in yeast and mammalian cells. Here, we investigated peroxisomal protein import and its dynamics in mitotic mammalian cells. In mitotically arrested cells, Pex14p is phosphorylated at Ser-232, resulting in a lower import efficiency of catalase, but not the majority of proteins including canonical PTS1 proteins. Conformational change induced by the mitotic phosphorylation of Pex14p more likely increases homomeric interacting affinity and suppresses topological change of its N-terminal part, thereby giving rise to the retardation of Pex5p export in mitotic cells. Taken together, these data show that mitotic phosphorylation of Pex14p and consequent suppression of catalase import are a mechanism of protecting DNA upon nuclear envelope breakdown at mitosis

Reconstruction of the Midfoot Area with Vascularized Chimeric Osteocutaneous Scapula Flap: A Case Report

We report a case of reconstruction of a left midfoot defect with a chimeric partial scapula and skin flap in a 20-year-old man. After radical debridement, bone and soft tissue defects were reconstructed with a chimeric scapula and skin flap. The postoperative course was uneventful. The patient could walk well without support, and bone union was achieved 6 months after surgery. In 14 months of follow-up, no clinical complications (including new ulcer or stress fracture) were noted and full ambulation was achieved, with the patient returning to his previous work. We suggest that the chimeric scapula and skin flap may be a useful alternative option for midfoot reconstruction

Enhancement of Dormant Pathways in the Brain following Rat Contusive Spinal Cord Injury

Spinal cord injury (SCI) induces distal effects on neural activity in the brain. To date, precise, high quality anatomical studies have not been performed. The goal of this study was to delineate neuroanatomical enhancement of dormant pathways in the brain following SCI using an appropriate serotype of an adeno-associated-virus (AAV) with a CAG promotor

Processes of Osteophyte Formation in Guinea Pigs with Spontaneous Osteoarthritis

In this study, we investigated osteophyte formation processes in guinea pigs with spontaneous osteoarthritis, histochemically and immunohistochemically. Serial thin frontal sections of right knee joints were prepared from Hartley guinea pigs aged 1, 3, 5, 8, 12 and 18 months. The severity of osteoarthritis was evaluated by safranin-O staining, and the animals were classified into 3 groups: mild, moderate and severe. In addition, immunostaining was performed by using primary antibodies against the proliferating cell nuclear antigen (PCNA), type-I, -II and -III collagens, insulin-like growth factor 1 (IGF-1) and IGF-1 receptor. In the mild group, there was fibrous connective tissue continuous with the synovial membrane and covering the margins of the articular cartilage of the medial tibial condyle. This tissue contained spindle-shaped fibroblastic-like cells. These cells were positive for PCNA, type-I and -III collagens, IGF-1 and IGF-1 receptor. In the moderate group, the chondrocytes beneath the fibroblastic-like cell layer had proliferated and were clustered together. These chondrocytes were also positive for PCNA, type-I and -III collagens, IGF-1 and IGF-1 receptor. In the severe group, this marginal area had been replaced by type-II collagen-positive chondrophytes, which further changed to osteophytes due to the process of endochondral ossification. In guinea pigs, fibroblastic-like cells at the margins of the articular cartilage of the knee joints seemed to be totipotent immature mesenchymal cells. These cells may be the precursors of osteophytes, and IGF-1 appears to be involved in their formation

Unveiling charge dynamics of visible light absorbing oxysulfide for efficient overall water splitting

Oxysulfide semiconductor, Y2Ti2O5S2, has recently discovered its exciting potential for visible-light-induced overall water splitting, and therefore, imperatively requires the probing of unknown fundamental charge loss pathways to engineer the photoactivity enhancement. Herein, transient diffuse reflectance spectroscopy measurements are coupled with theoretical calculations to unveil the nanosecond to microsecond time range dynamics of the photogenerated charge carriers. In early nanosecond range, the pump-fluence-dependent decay dynamics of the absorption signal is originated from the bimolecular recombination of mobile charge carriers, in contrast, the power-law decay kinetics in late microsecond range is dominated by hole detrapping from exponential tail trap states of valence band. A well-calibrated theoretical model estimates various efficiency limiting material parameters like recombination rate constant, n-type doping density and tail-states parameters. Compared to metal oxides, longer effective carrier lifetime ~6 ns is demonstrated. Different design routes are proposed to realize efficiency beyond 10% for commercial solar-to-hydrogen production from oxysulfide photocatalysts

重度大動脈弁狭窄症患者の大動脈弁置換術後における血小板機能および高分子量 von Willebrand 因子多量体の急速な回復

AIM: Patients with severe aortic stenosis (AS) may have bleeding episodes due to the loss of high-molecular-weight (HMW) von Willebrand factor multimers (VWFMs). The absence of HMW-VWFMs and bleeding tendency are usually corrected after aortic valve replacement (AVR). To investigate the process of VWFM recovery and symptoms in patients with severe AS, we analyzed changes in VWF antigen (VWF:Ag), ADAMTS13 activity (ADAMTS13:AC), and platelet thrombus formation under high shear stress conditions. METHODS: Nine patients with severe AS undergoing AVR were analyzed. RESULTS: Evident deficiency of HMW-VWFMs was observed in six patients before surgery, which was rapidly restored within 8 days after AVR. Median levels of VWF:Ag before surgery, on postoperative days (PODs) 1, 8, 15, and 22, and one year after AVR were 78.1%, 130%, 224%, 155%, 134%, and 142%, respectively. In contrast, ADAMTS13:AC was 50.5%, 35.5%, 25.5%, 25.1%, 30.3%, and 84.6%, respectively. Preoperative thrombus formation but not surface coverage was significantly lower than that on POD 22, which was considered as normal level in each patient. Compared with preoperative levels, thrombus volume was significantly lower on POD 1, but rapidly increased by POD 8. CONCLUSION: Bleeding tendency and loss of HMW-VWFMs observed in patients with severe AS before surgery was rapidly corrected after AVR. Instead, patients were in a VWF-predominant state between POD 8 and 22.博士（医学）・乙第1395号・平成29年3月15日Copyright © 2016 Japan Atherosclerosis Society本論文の著作権は日本動脈硬化学会が保持しています。This article is distributed under the terms of the latest version of CC BY-NC-SA defined by the Creative Commons Attribution License

Various Types of HIV Mixed Infections in Cameroon

AbstractIn order to assess the incidence of HIV mixed infection as well as to clarify the molecular epidemiology of HIV in central Africa, we investigated 43 HIVs obtained from 211 Cameroonian AC, ARC, and AIDS patients in 1994 and 1995. Part of thepolregion and part of theenvregion were phylogenetically analyzed. The genotypes observed were varied: of 43 specimens, 28 (65%) were subtype A, 1 (2%) was subtype B, 2 (5%) were subtype D, 3 (7%) were subtype F, and 2 (5%) were group O. Of the remaining 7 specimens, 3 were mixed infections with HIV-1 subtypes A and C, HIV-1 subtypes C and F, and HIV-2 subtype A and HIV-1 subtype A; 1 was a mixed infection with HIV-1 subtypes A and D and the highly divergent group O (triple infection); another 3 appeared to consist of mosaic genomes (A/G, A/E, and B/A recombinant). These data show that various types of mixed infection, such as between different subtypes of HIV-1 group M, between HIV-1 and HIV-2, and even between HIV-1 groups O and M, were confirmed at a rather high frequency (approximately 10%). The mixed infection is particularly significant where there is a greater variety of HIV-1 subtypes circulating, since it results in new genetic diversity generated by intersubtype recombination