University Of Tsukuba Research Articles

Preface

The 6th International Conference on Software Engineering & Computer Systems (ICSECS’19) organised by Faculty of Computing, Universiti Malaysia Pahang, is a biennial conference series that serves as a forum for international community of researchers, practitioners and industries in subfield of Software Engineering and Computer Systems. This year it held in Vistana Kuantan City Center, Kuantan, Pahang, Malaysia from 25-26 September 2019 with the theme of IR 4.0: Eyeing The Future. We are profound to promote the conference to a wider community by contributing the matters of public concern and future applications in the fields of software engineering and computer system with IR 4.0.Three keynote speakers were invited based on their expertise areas. The first keynote speaker was Professor Dr. Ts. Kamal Zuhairi bin Zamli from Universiti Malaysia Pahang. As a well-known professor in software testing, he delivers a speech on “Optimization via Meta/Hyper Heuristics: Achievements & Prospects for the Future”. The second keynote speaker was Professor Dr. Yuko Hatano from University of Tsukuba, Japan. She delivered her keynote speech on “Supercomputing by the Oakforest of University of Tsukuba Regarding the Flow in Porous Media”. The last speaker was Dr. Ishkandar bin Baharin, the President of Malaysia Robotics and Automation Society (MyRAS). His speech ws on “Bridging the Robotics and Automation Gap for IR 4.0 Adoption for local SMEs and the role of Local Academia”.This proceeding book is a compilation of selected papers that are submitted and presented in the conference. The content of the proceeding book is structured based on 4 conference tracks. The track has emphasized on the following topics include, but not limited to:Track 1: Internet of Things, Big Data and Autonomous RobotsTrack 2: Simulation and Virtual/Augmented RealityTrack 3: Additive Manufacturing and System IntegrationTrack 4: Cyber-Security and Cloud ComputingThe editors would like to extend their gratitude to all reviewers and program committees for the hard works. They would also like to thank to all presenters and participants for sharing their research and innovation outcomes in this conference. In addition, their special appreciation is dedicated to the sponsors, namely Malaysian Communications and Multimedia Commission, UMP Holdings, UMP Advance Education, Purnama Sdn. Bhd., Optik Prima Sdn. Bhd., KARAR Solutions Sdn. Bhd., Brilliant Grid Resources and Kafe Bonda Habsah Universiti Malaysia Pahang. Last but not least, the editors would like to thank to all for their enormous supports in this conference.

Meet the First Author.

HomeCirculation ResearchVol. 126, No. 3Meet the First Author Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBMeet the First Author Originally published30 Jan 2020https://doi.org/10.1161/RES.0000000000000324Circulation Research. 2020;126:296–297is related toFunctional Screening of Candidate Causal Genes for Insulin Resistance in Human Preadipocytes and AdipocytesAge-Associated Mitochondrial Dysfunction Accelerates AtherogenesisA Balance Between Intermediate Filaments and Microtubules Maintains Nuclear Architecture in the Cardiomyocyteis related toInterleukin-10 Deficiency Alters Endothelial Progenitor Cell–Derived Exosome Reparative Effect on Myocardial Repair via Integrin-Linked Kinase EnrichmentDuration and Life-Stage of Antibiotic Use and Risks of All-Cause and Cause-Specific MortalityVascular Aging, Mitochondria, and Atherogenesis (p 298)Download figureDownload PowerPointDr Dan Tyrrell is a postdoctoral fellow in Dr Daniel Goldstein’s laboratory at the University of Michigan. He completed his PhD in Dr Anthony Molina’s laboratory in Integrative Physiology and Pharmacology at Wake Forest School of Medicine. Dan’s recent work demonstrates a positive feedback loop of increased IL-6 and mitochondrial dysfunction within the aging aorta that accelerates atherogenesis. His long-term goal is to determine how mitochondria and inflammation interact in multiple vascular beds with aging, and how these changes enhance disease. Dan enjoys running and biking when he isn’t spending time with his family (ie, chasing after his two young sons). He can be found on Twitter @dantyrr.IL-10 Deficiency Impairs EPC Exosome Function (p 315)Download figureDownload PowerPointDr Yujia Yue earned her BS in Medicine from Fudan University in China. She became interested in life sciences and basic biomedical research while earning her MD. She came to the US in 2014 and completed her PhD in May 2019 (mentor, Dr Raj Kishore) at the Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, focusing on stem cell-derived exosome in cardiac regeneration. After earning her PhD, Yujia joined Merck as an Associate Scientist. She is interested in furthering her scientific pursuit of translational medicine and drug discovery and plans to continue her scientific career in industry.CRISPR Screen for Genes Affecting Insulin Resistance (p 330)Download figureDownload PowerPointDr Zhifen Chen is a postdoctoral fellow in Dr Chad Cowan’s group at the Harvard Stem Cell Institute, where her research focuses on functional genomics of polygenic traits, including insulin resistance and glucose levels. She earned her PhD from Technical University of Munich (TUM) in 2016 and her MS from Tsinghua University, Beijing, in 2012. She was mentored by Dr Karl-Ludwig Laugwitz, focussing on cardiac disease modelling using patient-induced pluripotent stem cell (iPSC)-derived cardiomyocytes, including a type of long QT syndrome and a case of familial dilated cardiomyopathy. The goal of her research is to identify unknown genes contributing to adipose insulin resistance and test their therapeutic potentials for obesity or type 2 diabetes and their related cardiometabolic comorbidities. Outside of the lab, she enjoys dancing, biking, and discussing life experiences and diverse fields of science. She plans to establish her own lab in the near future.Desmin and the Nucleus (p e10)Download figureDownload PowerPointJulie Heffler is a doctoral candidate at the University of Pennsylvania in the lab of Dr Ben Prosser. She began her career as an undergraduate at the University of Houston, where she earned her BS in Biochemistry. During her time at UH, she worked in the lab of Dr Kevin Morano at UT Health researching chaperones and protein misfolding. Currently, her research at UPenn has focused on the attachment of the cytoskeleton to the nucleus in adult cardiomyocytes and how these cells sense mechanical signals, continuing her long-held interest in cell sensing and signal transduction. She can be found on Twitter @julieheffler.Antibiotics and Risk of Mortality (p 364)Download figureDownload PowerPointDr Yoriko Heianza is a postdoctoral research fellow in the Department of Epidemiology at Tulane University. She earned her PhD in Medicine from the University of Tsukuba, Japan. She previously earned her BS from the Doshisha Women’s College of Liberal Arts, Kyoto, Japan, where she gained a broad knowledge of nutrition. She has been exploring genetic, metabolomic, diet/lifestyle factors in the development of obesity and cardiovascular disease in Dr Lu Qi’s Lab at Tulane University, with the support of an AHA Postdoctoral Fellowship. She has also received two awards for her research from the AHA. Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesFunctional Screening of Candidate Causal Genes for Insulin Resistance in Human Preadipocytes and AdipocytesZhifen Chen, et al. Circulation Research. 2020;126:330-346Interleukin-10 Deficiency Alters Endothelial Progenitor Cell–Derived Exosome Reparative Effect on Myocardial Repair via Integrin-Linked Kinase EnrichmentYujia Yue, et al. Circulation Research. 2020;126:315-329Age-Associated Mitochondrial Dysfunction Accelerates AtherogenesisDaniel J. Tyrrell, et al. Circulation Research. 2020;126:298-314A Balance Between Intermediate Filaments and Microtubules Maintains Nuclear Architecture in the CardiomyocyteJulie Heffler, et al. Circulation Research. 2020;126:e10-e26Duration and Life-Stage of Antibiotic Use and Risks of All-Cause and Cause-Specific MortalityYoriko Heianza, et al. Circulation Research. 2020;126:364-373 January 31, 2020Vol 126, Issue 3 Advertisement Article InformationMetrics © 2020 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000324PMID: 31999534 Originally publishedJanuary 30, 2020 PDF download Advertisement

Creating opportunities to discuss the nature of Japanese science communication

Build SciComm, an international symposium on strategies for fostering science communication in Japan held at the University of Tsukuba in November 2019, brought together academics and practitioners to discuss issues faced by the field in Japan and vision for future direction. Informally, the symposium was well received and generally considered to be a useful and stimulating event. We discuss issues to be considered for future incarnations and explain why this symposium provides an important forum for inclusive discussions on fundamental questions about the nature of science communication in Japan.

7-2 Initial Experience of Online Problem-based Learning Tutorial at the University of Tsukuba

7-2 Initial Experience of Online Problem-based Learning Tutorial at the University of Tsukuba

8-1 Approaches to Online Clinical Clerkship at the University of Tsukuba, the Department of Gastroenterology under the COVID-19 Outbreak

8-1 Approaches to Online Clinical Clerkship at the University of Tsukuba, the Department of Gastroenterology under the COVID-19 Outbreak

筑波大学自然保護寄附講座編『自然保護学入門─ひとと自然をつなぐ─』（書評）

筑波大学自然保護寄附講座編『自然保護学入門─ひとと自然をつなぐ─』（書評）

4-1 Effects of Online Meetings between the Dean and Students on Clerkship at the University of Tsukuba, College of Medicine

4-1 Effects of Online Meetings between the Dean and Students on Clerkship at the University of Tsukuba, College of Medicine

Application of principle component Analysis in differentiating the three types of Amaranthus based on their photoperiodic flowering response

Response of flowering has become an attracting field for plant breeders and is pre-requisite in plant introduction process from different ecogeographical origins. Time of flowering is mostly induced by the day-length or photoperiod and temperature. Amaranth (Amaranthus sp.) is known as multipurpose plants and utilized as grains or as vegetables. Under tropical environment, likewise in Indonesia, the requirement of day-length to induce flowering in amaranths is unrevealed as the day-length remains always constant with approximately 12 hours per day. During the introduction of amaranth to Japan, we would like to confirm the type of amaranth, which in general has been theoretically classified as short day plants. Under the variation of day-length ranging from 9 up to 15 hours during the four seasons in Japan, thus, we confirmed that amaranth as short day plants. Although, the vegetable ones required day-length up to 12 hours. Such conclusion was obtained from the flowering response of 69 accessions representing amaranth’s eco-geographical variations within two consecutive years. Seeds were sown in two replicates. Plant nursery was conducted on the Norin-Ijutsu Centre belongs to the University of Tsukuba. Mean values from two replicates were obtained and the average was then further subjected to Principle Component Analysis (PCA) [JMP ver. 7.0 (SAS Institute, USA)]. Thus, PCA was able to differentiate the flowering tendency within the three types of amaranths in the form of three ellipsoids. A post-publication change was made to this article on 11 Mar 2020 to correct the conference title in the PDF header.

On achievements and challenges of the University of Tsukuba’s “Global Education Program for Developing Multilingual Human Resources in Japan, NIS and Baltic Countries (Ge-NIS)”

On achievements and challenges of the University of Tsukuba’s “Global Education Program for Developing Multilingual Human Resources in Japan, NIS and Baltic Countries (Ge-NIS)”

Clinical implications of breast ultrasound elastography

Abstract Breast cancer is the most common cancer in Polish women and the second leading cause of cancer deaths. Screening mammography is the only recognized method for early detection of malignant neoplasm and provides to reduction in cancer related deaths so far. The sensitivity of this examination is strongly influenced by the structure of the breast and is definitely lower for breasts of type 2 and 3 in accordance to American College of Radiology. That is why it is suggested that women younger than 35 years should be examined with ultrasound if necessary, and for women 35 years and older it is recommended to perform mammography, as the primary breast study. Ultrasound elastography is noninvasive imaging technique which can contribute to increase the sensitivity and specificity of recognition breast lesions. There are two main types of elastography: static and shear wave one. According to tissue stiffness, static elastography encodes lesions using a 5-point color scale – the Tsukuba University Score. Improvements in the interpretation of non-invasive examinations with using ultrasound elastography were discussed. It is considered that addition ultrasound elastography to ultrasound B-mode can play an important role in verification focal lesions in the breast.

Multiplex exome sequencing reveals genome-wide frequency and distribution of mutations in the 'Micro-Tom' Targeting Induced Local Lesions in Genomes (TILLING) mutant library.

While the 'Micro-Tom' TILLING mutant library is used for a wide range of purposes, including both basic research of gene function and breeding of commercial cultivars, genome-wide distribution and frequency of mutations have not yet been thoroughly elucidated on a population scale. In this study, we developed a 96-plex exome sequencing method to identify and analyze mutations within the TILLING mutants that were developed in the University of Tsukuba. First, an Illumina paired-end sequencing coupled with 96-plex exome capture resulted in the acquisition of an exome sequence dataset with an average read count of 5.6 million for the 95 mutants. Over 98% of the capture target region could be covered by the short reads with an averaged read depth of 12.8, which enabled us to identify single nucleotide polymorphisms and Indels in a genome-wide manner. By subtracting intra-cultivar DNA variations that are present between wild-type 'Micro-Tom' lines, we identified 241,391 mutation candidates in 95 mutant individuals. Of these, 64,319 and 6,480 mutations were expected to cause protein amino acid substitutions or premature stop codon, respectively. Based on the exome mutation dataset, a mutant line designated 'TOMJPW601' was found to carry a premature stop codon mutation (W261*) in a putative auxin influx carrier gene SlLAX1 (Solyc09G014380), consistent with our previous report of its curly leaf phenotype. Our results suggested that a population-scale mutation database developed by multiplexed exome sequencing could be used for in silico mutant screening, which in turn could contribute to both gene function research and breeding programs.

Isolation and characterization of mesenchymal stem cells derived from type 2 diabetes – research conducted in the Regenerative Medicine and Stem Cell Biology Lab (Ohneda Lab)

Stem cells are one of the leading methods through which we will gain the next generation of medical treatments. Given their ability to develop into almost any cell type, the medical applications are endless. Since the methods through which to reprogramme these master progenitors were established, many tests and clinical trials have taken place. However, as is often the case in biology, the picture is more complicated than simply reprogramming these cells with a cocktail of proteins. Stem cell expert Professor Osamu Ohneda is a Principal Investigator at the University of Tsukuba, Japan. 'Our focus is to achieve autologous transplantation whereby, mesenchymal stem cells are taken from the patient, encouraged to grow and reprogrammed before transplantation into the patient,' he observes. This process would be a crucial step in the personalisation of medicine, however, the more this process has been tested, the clearer it has become that additional variables are in play. 'There have been issues with nearly every step of the process after the acquirement of the raw mesenchymal stem cells (MSCs) necessary,' Ohneda highlights. 'The MSCs don't always respond as expected to growth stimulants and differentiation cues and transplants don't always take.' More in depth research is needed to overcome these issues and turn stem cell's potential into a reality. Investigating and solving these issues is the work of Ohneda and his research team, including Assistant Professor Vuong Cat Khanh and Assistant Professor Toshiharu Yamashita.

Radiocarbon dating of Chinese Ancient Tea Trees

ABSTRACTThe jungles of Linyun and Longlin Autonomous Prefecture, located in the heart of the southwestern Guangxi Zhuang Autonomous Region of China, are home to the oldest tea trees (Camellia sinensis) in the world. In the absence of regular annual rings, radiocarbon (14C) dating is one of the most powerful tools that can assist in the determination of the ages and growth rates of these plants. In this work, cores were extracted from large ancient tea trees in a central Longlin rain forest; extraction of carbon was performed with an automated sample preparation system. The 14C levels in the tree cores were measured using accelerator mass spectrometry (AMS) at the University of Tsukuba. These measurements indicated that contrary to conventional views, the ages of trees in these forests range up to ~700 years, and the growth rate of this species is notably slow, exhibiting a long-term radial growth rate of 0.039±0.006 cm/yr. It was demonstrated that 14C analyses provide accurate determination of ages and growth rates for subtropical wild tea trees.

A single-institute experience of trimodal bladder-preserving therapy for histologic variants of urothelial carcinoma.

We retrospectively evaluated the clinical outcomes of patients with histologic variants of muscle invasive bladder cancer (MIBC) treated with trimodal bladder-preserving therapy (TMT). Among 148 patients with clinical T2-3N0M0 MIBC treated with TMT at Tsukuba University Hospital from 1990 to 2015, 11 patients (7.4%) had pathological components of variant urothelial carcinoma (UC). The complete response (CR), overall survival (OS), cause-specific survival (CSS) and progression-free survival (PFS) rates were analyzed in these 11 patients. Among the 11 patients with variant UC, 7 (64%) had UC with squamous and/or glandular differentiation and 4 (36%) had sarcomatoid (n = 1), plasmacytoid (n = 1), signet ring cell (n = 1), or clear cell variant (n = 1). Median follow-up was 49.0months. Nine (82%) out of 11 patients achieved CR and 2 (22%) out of the 9 developed recurrence. Among seven patients who had UC with squamous and/or glandular differentiation, two developed recurrence and one died of disease. In contrast, 2 (50%) out of four patients with other variants, which were sarcomatoid variant or signet ring cell, developed recurrence and died of disease. Overall, the 5-year OS, CSS, and PFS rates of variant UC were 75%, 75%, and 58%, respectively. TMT might provide acceptable clinical outcomes for well-selected MIBC patients with histologic variants, especially for those with squamous and/or glandular differentiation. However, we need to pay special attention to other variants such as sarcomatoid variant or signet ring cell. TMT might be an alternative treatment option for patients with histologic variants, although further experiments will be needed to confirm this.

Influence of Living Environment during Childhood on Helicobacter pylori Infection in Japanese Young Adults

Introduction: Helicobacter pylori infection is usually established during childhood, for which certain responsible environmental factors have been identified. However, the details of the infection routes remain unclear. Objective: To determine the relation between H. pylori infection statuses and living environment of Japanese young adult. Methods: The subjects were 449 healthy young adult medical students of Tsukuba University (299 men and 150 women, mean age: 22.8 years). The H. pylori infection statuses were investigated using the rapid urease test or urine antibody. Questionnaires regarding sanitary conditions including usage of pit toilet or well water and experience of living with one’s grandparents during childhood were surveyed. Each item was compared between the H. pylori-positive and -negative groups. Results: Among all participants, 33 (7.3%) were H. pylori-positive. The usage rates of pit toilets were 12.1 and 3.1% for the H. pylori-positive and -negative groups respectively (p = 0.03; OR 4.35, 95% CI 1.33–14.22). The usage rates of well water were 24.2 and 13.7% for the H. pylori-positive and -negative groups respectively (p = 0.07; OR 2.12, 95% CI 0.91–4.98). The proportion of participants with a history of living with their grandparents was significantly greater in the H. pylori-positive group (46.7%) than in the -negative group (20.9%; p = 0.03; OR 3.28, 95% CI 1.13–9.54). Only a history of living with one’s grandparents during childhood showed statistical significance in the multivariate regression analysis (p = 0.04; OR 3.20, 95% CI 1.08–9.49). Conclusions: These results suggest that H. pylori infection is more strongly related to living with one’s grandparents than living in a hygienic environment.

Why Do Athletes Choose Dietary Supplements? Reliability and Validity of the Dietary Supplement Choice Questionnaire (DSCQ) among Japanese College Athletes.

To assess the reliability and validity of the Dietary Supplement Choice Questionnaire (DSCQ) to capture dietary supplement choice motives among Japanese college athletes. The cross-sectional study was performed in 2014. This study recruited 1,451 college athletes from sports-oriented clubs at the University of Tsukuba, Japan. The participants completed the DSCQ, health literacy, and subjective economic status; part of the participants completed a test-retest (n=378). A sample of 975 participants (28.0% female) included in the analysis. The DSCQ was developed through factor analysis. Seven factors emerged, and were labelled "popularity," "functionality," "price," "taste," "convenience," "antidoping" and "familiarity." Mostly acceptable reliability was seen across seven DSCQ factors (the internal consistency, Cronbach's α=0.62-0.85; the test-retest reliability coefficients, r=0.62-0.82), whereas convergent validity for price and antidoping factors was provided by significant associations with economic status and literacy (p<0.01). Findings showed reasonable evidence of reliability and validity of the DSCQ and provided the opportunity to comprehensively assess dietary supplement choice motives among Japanese college athletes.

Clinical and experimental evaluation of new back-flow hydrodissection technique

To assess the efficacy and safety of a new technique, back-flow hydrodissection. Hirota Eye Clinic, Yamaguchi, and Department of Ophthalmology, University of Tsukuba, Ibaraki, Japan. Prospective case series and experimental study. For back-flow hydrodissection, the irrigation line was connected to the aspiration port of an irrigation/aspiration handpiece using a female-female connector with the irrigation port open. The balanced salt solution was irrigated from the aspiration tip opening with constant pressure, hydrodissection was performed, and the excess fluid was evacuated via the sleeve lumen. In a clinical study, 200 eyes were randomly assigned to conventional hydrodissection with an irrigation cannula or back-flow hydrodissection. In experimental studies, intraocular pressure (IOP) fluctuation and fluid dynamics in the anterior and posterior chamber were evaluated in porcine eyes. The lens became freely mobile in the capsular bag in 99 (99%) of 100 eyes and in 96 (96%) of 100 eyes in the back-flow hydrodissection group and conventional hydrodissection group, respectively (P=.369). There were no between-group differences in any other surgery-related parameters, including surgical time and the complication rate. In porcine eyes, conventional hydrodissection induced a significantly larger increase in IOP than back-flow hydrodissection (P<.0001). Conventional hydrodissection immediately washed out fluorescein-stained ophthalmic viscosurgical device (OVD) from the anterior chamber, while there was little leakage of OVD from the eye with back-flow hydrodissection. The endoscopic view showed that conventional hydrodissection induced rapid and severe bulging of the posterior capsule; however, bulging was gentle and mild with back-flow hydrodissection. Back-flow hydrodissection was safe and effective in disengaging the lens from the capsule, ensuring a freely mobile lens.

Audiovisual telesupport system for cardiovascular catheter interventions: A preliminary report on the clinical implications.

This study aimed to validate the clinical implications of audiovisual telesupport system use. An audiovisual telesupport system with supervisors has been effective in guiding procedures when surgeons have limited experience with the technique. However, cardiovascular catheter interventions using an audiovisual telesupport system has not been previously reported. Starting in September 2017, two cardiologists in Kamisu Saiseikai Hospital (Kamisu, Japan, with limited cardiologists) began performing cardiovascular catheter interventions using an audiovisual telesupport system. This system enabled them to perform catheter interventions with the support of advisors in the University of Tsukuba (Tsukuba, Japan). We retrospectively assessed procedure time and complications of percutaneous coronary intervention (PCI) and catheter ablation (CA). In the first 10 months, 21 patients with coronary artery disease underwent PCI using this system. The mean procedure duration of PCI was 42 ± 10 min. Nine patients with tachyarrhythmia including supraventricular tachycardia (SVT), ventricular premature contraction (VPC), common atrial flutter, and paroxysmal atrial fibrillation (AF) underwent CA using this system. The mean CA procedure time was 134 ± 31 min for SVT, 100 ± 14 min for VPC, and 200 min for AF. All PCI and CA procedures were successfully performed without any complications. The audiovisual telesupport system enabled cardiologists with limited human resources to provide safe and high-quality catheter interventions.

Spatial Analysis of Urbanization in Major Asian and African Cities

Abstract. The world statistics shows that 54% of the world population had been accumulated in urbanized areas by 2014. It is estimated that the global urban population will be increasing up to 66% of the total by 2050. According to the United Nations (UN) projection, the urbanization will be faster in Asian and African countries than the other continents. It is obvious this rapid increase will bring about serious socio-economic and environmental problems in the near future. Thus the geographical thinking of urbanization is becoming a vital topic to introduce proper urban planning for the future sustainability.Many geographers have focused on the urbanization pattern and process of the developing countries during the last two decades. In this connection, the scarcity of the spatial data has been an obstacle to study quantitatively urbanization especially in Asian and African cities. Based on this background, since the 2000s, the Division of Spatial Information Sciences, University of Tsukuba, has conducted the research to establish the city-based spatial information platform to overcome this obstacle, i.e., the lack of the data. The main objective of this project is to capture the urbanization pattern and process over the time by using Remote Sensing (RS) and Geographical Information Systems (GIS) techniques. The data on land use and land cover, land surface temperature, energy consumption, and population density are now available with the same spatial resolution in terms of selected cities.Our goal is to open the web-based GIS system to provide the geospatial database of Asian and African cities and scientifically discuss the urban sustainability by using scenario-based simulation. The projected future scenario will be useful for the urban policy by the “back-casting method.”

「サービス工学×AI」と品質向上：筑波大学の経験から

「サービス工学×AI」と品質向上：筑波大学の経験から