{"id":"https://openalex.org/A5110086052","orcid":null,"observed_orcids":[],"display_name":"K. Koyama","raw_author_names":["K Koyama","K. KOYAMA","K. Koyama","Keita Koyama"],"full_name":"Keita Koyama","works_count":20,"cited_by_count":51,"summary_stats":{"2yr_mean_citedness":0.0,"h_index":3,"i10_index":2},"ids":{"openalex":"https://openalex.org/A5110086052","orcid":null,"observed_orcids":[]},"affiliations":[{"institution":{"id":"https://openalex.org/I125602781","ror":"https://ror.org/051k3eh31","display_name":"Tokyo Medical and Dental University","country_code":"JP","type":"education","lineage":["https://openalex.org/I125602781","https://openalex.org/I4400009020"]},"years":[2001]},{"institution":{"id":"https://openalex.org/I165735259","ror":"https://ror.org/046fm7598","display_name":"Gunma University","country_code":"JP","type":"education","lineage":["https://openalex.org/I165735259"]},"years":[2000]},{"institution":{"id":"https://openalex.org/I40677808","ror":"https://ror.org/028vxwa22","display_name":"Kyoto Prefectural University of Medicine","country_code":"JP","type":"education","lineage":["https://openalex.org/I40677808","https://openalex.org/I4405285717"]},"years":[1989]},{"institution":{"id":"https://openalex.org/I4210129341","ror":"https://ror.org/037403209","display_name":"Gunma Prefectural Cardiovascular Center","country_code":"JP","type":"healthcare","lineage":["https://openalex.org/I4210129341"]},"years":[2017]},{"institution":{"id":"https://openalex.org/I4210152580","ror":"https://ror.org/04emv5a43","display_name":"Tokyo Metropolitan Geriatric Hospital","country_code":"JP","type":"healthcare","lineage":["https://openalex.org/I4210152580"]},"years":[1998]},{"institution":{"id":"https://openalex.org/I4210164827","ror":"https://ror.org/05kq1z994","display_name":"Gunma University Hospital","country_code":"JP","type":"healthcare","lineage":["https://openalex.org/I4210164827"]},"years":[2000]}],"last_known_institutions":null,"topics":[{"id":"https://openalex.org/T10977","display_name":"Optical Imaging and Spectroscopy Techniques","count":4,"subfield":{"id":"https://openalex.org/subfields/2741","display_name":"Radiology, Nuclear Medicine and Imaging"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}},{"id":"https://openalex.org/T10985","display_name":"Sleep and Wakefulness Research","count":4,"subfield":{"id":"https://openalex.org/subfields/2805","display_name":"Cognitive Neuroscience"},"field":{"id":"https://openalex.org/fields/28","display_name":"Neuroscience"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},{"id":"https://openalex.org/T10155","display_name":"Nitric Oxide and Endothelin Effects","count":2,"subfield":{"id":"https://openalex.org/subfields/2737","display_name":"Physiology (medical)"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}},{"id":"https://openalex.org/T10445","display_name":"Antioxidant Activity and Oxidative Stress","count":2,"subfield":{"id":"https://openalex.org/subfields/2704","display_name":"Biochemistry (medical)"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}},{"id":"https://openalex.org/T10522","display_name":"Medical Imaging Techniques and Applications","count":2,"subfield":{"id":"https://openalex.org/subfields/2741","display_name":"Radiology, Nuclear Medicine and Imaging"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}}],"topic_share":[{"id":"https://openalex.org/T10985","display_name":"Sleep and Wakefulness Research","value":2.63e-05,"subfield":{"id":"https://openalex.org/subfields/2805","display_name":"Cognitive Neuroscience"},"field":{"id":"https://openalex.org/fields/28","display_name":"Neuroscience"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}},{"id":"https://openalex.org/T10977","display_name":"Optical Imaging and Spectroscopy Techniques","value":1.97e-05,"subfield":{"id":"https://openalex.org/subfields/2741","display_name":"Radiology, Nuclear Medicine and Imaging"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}},{"id":"https://openalex.org/T11867","display_name":"Traumatic Ocular and Foreign Body Injuries","value":1.28e-05,"subfield":{"id":"https://openalex.org/subfields/2731","display_name":"Ophthalmology"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}},{"id":"https://openalex.org/T11579","display_name":"Cardiovascular and Diving-Related Complications","value":1.19e-05,"subfield":{"id":"https://openalex.org/subfields/2740","display_name":"Pulmonary and Respiratory Medicine"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}},{"id":"https://openalex.org/T11485","display_name":"Gastrointestinal Tumor Research and Treatment","value":1e-05,"subfield":{"id":"https://openalex.org/subfields/2715","display_name":"Gastroenterology"},"field":{"id":"https://openalex.org/fields/27","display_name":"Medicine"},"domain":{"id":"https://openalex.org/domains/4","display_name":"Health Sciences"}}],"x_concepts":[{"id":"71924100","wikidata":"https://www.wikidata.org/wiki/Q11190","display_name":"Medicine","score":0.976224422454834},{"id":"164705383","wikidata":"https://www.wikidata.org/wiki/Q10379","display_name":"Cardiology","score":0.6545592546463013},{"id":"126322002","wikidata":"https://www.wikidata.org/wiki/Q11180","display_name":"Internal medicine","score":0.6155334711074829},{"id":"15744967","wikidata":"https://www.wikidata.org/wiki/Q9418","display_name":"Psychology","score":0.530106782913208},{"id":"41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","score":0.34227004647254944}],"counts_by_year":[{"year":1967,"works_count":2,"oa_works_count":0,"cited_by_count":0},{"year":1970,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":1977,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":1982,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":1989,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":1990,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":1993,"works_count":2,"oa_works_count":0,"cited_by_count":0},{"year":1996,"works_count":2,"oa_works_count":0,"cited_by_count":0},{"year":1998,"works_count":5,"oa_works_count":1,"cited_by_count":0},{"year":2000,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":2001,"works_count":1,"oa_works_count":0,"cited_by_count":0},{"year":2012,"works_count":0,"oa_works_count":0,"cited_by_count":3},{"year":2013,"works_count":0,"oa_works_count":0,"cited_by_count":1},{"year":2014,"works_count":0,"oa_works_count":0,"cited_by_count":2},{"year":2015,"works_count":0,"oa_works_count":0,"cited_by_count":2},{"year":2017,"works_count":1,"oa_works_count":1,"cited_by_count":0},{"year":2020,"works_count":0,"oa_works_count":0,"cited_by_count":1},{"year":2021,"works_count":0,"oa_works_count":0,"cited_by_count":1},{"year":2022,"works_count":0,"oa_works_count":0,"cited_by_count":3},{"year":2023,"works_count":0,"oa_works_count":0,"cited_by_count":1},{"year":2024,"works_count":1,"oa_works_count":1,"cited_by_count":1},{"year":2025,"works_count":0,"oa_works_count":0,"cited_by_count":2},{"year":2026,"works_count":0,"oa_works_count":0,"cited_by_count":2}],"display_name_alternatives":["K Koyama","K. KOYAMA","K. Koyama","Keita Koyama"],"block_key":"k koyama","works_api_url":"https://api.openalex.org/works?filter=author.id:A5110086052","updated_date":"2026-11-04T11:47:51","created_date":"2016-06-24T00:00:00"}