World's Best Scientists 2026 revealed!

D-Index & Metrics

Biology and Biochemistry

D-Index
43
Citations
7122
World Ranking
19400
National Ranking
1399

Tomoichiro Oka publication distribution in Biology and Biochemistry in 2026

The chart shows the distribution of publications by all Research.com ranked scientists in the field of Biology and Biochemistry in 2026. The highlighted bar marks where Tomoichiro Oka sits on this spectrum.

47–56 publications: 8 scientists 57–66 publications: 35 scientists 67–76 publications: 106 scientists 77–86 publications: 231 scientists 87–96 publications: 414 scientists 97–106 publications: 546 scientists 107–116 publications: 704 scientists 117–126 publications: 849 scientists 127–136 publications: 980 scientists 137–146 publications: 942 scientists 147–156 publications: 969 scientists 157–166 publications: 950 scientists 167–176 publications: 951 scientists 177–186 publications: 915 scientists 187–196 publications: 787 scientists 197–206 publications: 841 scientists 207–216 publications: 735 scientists 217–226 publications: 709 scientists 227–236 publications: 651 scientists 237–246 publications: 605 scientists 247–256 publications: 510 scientists 257–266 publications: 524 scientists 267–276 publications: 434 scientists 277–286 publications: 418 scientists 287–296 publications: 350 scientists 297–306 publications: 363 scientists 307–316 publications: 315 scientists 317–326 publications: 296 scientists 327–336 publications: 261 scientists 337–346 publications: 240 scientists 347–356 publications: 219 scientists 357–366 publications: 197 scientists 367–376 publications: 154 scientists 377–386 publications: 161 scientists 387–396 publications: 155 scientists 397–406 publications: 145 scientists 407–416 publications: 124 scientists 417–426 publications: 112 scientists 427–436 publications: 132 scientists 437–446 publications: 116 scientists 447–456 publications: 99 scientists 457–466 publications: 81 scientists 467–476 publications: 91 scientists 477–486 publications: 80 scientists 487–496 publications: 80 scientists 497–506 publications: 60 scientists 507–516 publications: 36 scientists 517–526 publications: 46 scientists 527–536 publications: 54 scientists 537–546 publications: 44 scientists 547–556 publications: 43 scientists 557–566 publications: 43 scientists 567–576 publications: 42 scientists 577–586 publications: 25 scientists 587–596 publications: 34 scientists 597–606 publications: 23 scientists 607–616 publications: 33 scientists 617–626 publications: 31 scientists 627–636 publications: 27 scientists 637–646 publications: 25 scientists 647–656 publications: 28 scientists 657–666 publications: 34 scientists 667–676 publications: 18 scientists 677–686 publications: 16 scientists 687–696 publications: 10 scientists 697–706 publications: 12 scientists 707–716 publications: 21 scientists 717–726 publications: 12 scientists 727–736 publications: 12 scientists 737–746 publications: 10 scientists 747–756 publications: 7 scientists 757–766 publications: 13 scientists 767–776 publications: 15 scientists 777–786 publications: 13 scientists 787–796 publications: 9 scientists 797–806 publications: 9 scientists 807–816 publications: 7 scientists 817–826 publications: 4 scientists 827–836 publications: 9 scientists 837–846 publications: 7 scientists 847–856 publications: 3 scientists 857–866 publications: 5 scientists 867–876 publications: 5 scientists 877–886 publications: 11 scientists 887–896 publications: 3 scientists 897–906 publications: 4 scientists 907–916 publications: 7 scientists 917–926 publications: 5 scientists 927–936 publications: 6 scientists 937–946 publications: 6 scientists 947–956 publications: 3 scientists 957–966 publications: 7 scientists 967–976 publications: 2 scientists 977–986 publications: 2 scientists 987–996 publications: 1 scientists 997–1,006 publications: 5 scientists 1,007–1,016 publications: 2 scientists 1,017–1,026 publications: 2 scientists 1,027 publications: 1 scientists 1,028+ publications: 100 scientists
47 publications 1,028+

This scientist: 149 publications — 26th percentile

26% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 1,028 publications or more.

Tomoichiro Oka D-index placement in Biology and Biochemistry in 2026

The chart shows the D-index (discipline H-index) distribution of Biology and Biochemistry scientists ranked by Research.com in 2026. The highlighted bar marks where Tomoichiro Oka sits on this spectrum.

40–41 D-Index: 80 scientists 42–43 D-Index: 183 scientists 44–45 D-Index: 317 scientists 46–47 D-Index: 504 scientists 48–49 D-Index: 718 scientists 50–51 D-Index: 900 scientists 52–53 D-Index: 1,026 scientists 54–55 D-Index: 1,150 scientists 56–57 D-Index: 1,236 scientists 58–59 D-Index: 1,253 scientists 60–61 D-Index: 1,163 scientists 62–63 D-Index: 1,131 scientists 64–65 D-Index: 1,032 scientists 66–67 D-Index: 897 scientists 68–69 D-Index: 814 scientists 70–71 D-Index: 715 scientists 72–73 D-Index: 709 scientists 74–75 D-Index: 596 scientists 76–77 D-Index: 512 scientists 78–79 D-Index: 473 scientists 80–81 D-Index: 412 scientists 82–83 D-Index: 373 scientists 84–85 D-Index: 358 scientists 86–87 D-Index: 285 scientists 88–89 D-Index: 273 scientists 90–91 D-Index: 227 scientists 92–93 D-Index: 208 scientists 94–95 D-Index: 193 scientists 96–97 D-Index: 153 scientists 98–99 D-Index: 157 scientists 100–101 D-Index: 148 scientists 102–103 D-Index: 120 scientists 104–105 D-Index: 113 scientists 106–107 D-Index: 100 scientists 108–109 D-Index: 86 scientists 110–111 D-Index: 67 scientists 112–113 D-Index: 72 scientists 114–115 D-Index: 73 scientists 116–117 D-Index: 64 scientists 118–119 D-Index: 53 scientists 120–121 D-Index: 60 scientists 122–123 D-Index: 54 scientists 124–125 D-Index: 43 scientists 126–127 D-Index: 38 scientists 128–129 D-Index: 49 scientists 130–131 D-Index: 26 scientists 132–133 D-Index: 18 scientists 134–135 D-Index: 23 scientists 136–137 D-Index: 32 scientists 138–139 D-Index: 32 scientists 140–141 D-Index: 27 scientists 142–143 D-Index: 19 scientists 144–145 D-Index: 22 scientists 146–147 D-Index: 12 scientists 148–149 D-Index: 16 scientists 150–151 D-Index: 14 scientists 152–153 D-Index: 10 scientists 154–155 D-Index: 13 scientists 156–157 D-Index: 10 scientists 158–159 D-Index: 7 scientists 160–161 D-Index: 9 scientists 162–163 D-Index: 13 scientists 164–165 D-Index: 4 scientists 166 D-Index: 4 scientists 167+ D-Index: 98 scientists
40 D-Index 167+

This scientist: 43 D-Index — 1st percentile

1% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 167 D-Index or more.

Overview

What is he best known for?

The fields of study he is best known for:

  • Gene
  • DNA
  • Virus

His main research concerns Virology, Sapovirus, Norovirus, Genotype and Capsid. His Virology research incorporates elements of Phylogenetics and Microbiology. His Phylogenetics study which covers Genome that intersects with Recombinant DNA.

His study in Norovirus is interdisciplinary in nature, drawing from both Molecular epidemiology and Rotavirus. His research in Genotype is mostly concerned with Genotyping. The study incorporates disciplines such as Molecular typing, Pathogen, Mink and Disease in addition to Outbreak.

His most cited work include:

  • Coexistence of Multiple Genotypes, Including Newly Identified Genotypes, in Outbreaks of Gastroenteritis Due to Norovirus in Japan (371 citations)
  • Phylogenetic analysis of the complete genome of 18 Norwalk-like viruses. (279 citations)
  • Detection of human sapovirus by real-time reverse transcription-polymerase chain reaction (194 citations)

What are the main themes of his work throughout his whole career to date?

His primary scientific interests are in Virology, Sapovirus, Genotype, Norovirus and Genetics. Tomoichiro Oka combines subjects such as Recombinant DNA and Microbiology with his study of Virology. His Sapovirus research includes themes of Pathogen, Feces, Viral replication, Caliciviridae Infections and Sequence analysis.

His biological study spans a wide range of topics, including Phylogenetics and Whole genome sequencing. Tomoichiro Oka focuses mostly in the field of Norovirus, narrowing it down to topics relating to Molecular epidemiology and, in certain cases, Caliciviridae. His research investigates the connection between Capsid and topics such as Molecular biology that intersect with problems in Reverse transcription polymerase chain reaction.

He most often published in these fields:

  • Virology (78.72%)
  • Sapovirus (54.61%)
  • Genotype (34.04%)

What were the highlights of his more recent work (between 2015-2021)?

  • Virology (78.72%)
  • Sapovirus (54.61%)
  • Genome (21.28%)

In recent papers he was focusing on the following fields of study:

His primary areas of study are Virology, Sapovirus, Genome, Genetics and Phylogenetic tree. His Virology research integrates issues from Strain, Recombination and Pathogenesis. Genotype and Norovirus are inextricably linked to his Sapovirus research.

His Genotype study combines topics in areas such as Reverse transcription polymerase chain reaction, Cysteine protease, Outbreak, Complementary DNA and Primer. His work deals with themes such as Feces and Sequence analysis, which intersect with Genome. Tomoichiro Oka interconnects Wild boar, Phylogenetics, Virus and Metagenomics in the investigation of issues within Phylogenetic tree.

Between 2015 and 2021, his most popular works were:

  • Genetic Characterization and Classification of Human and Animal Sapoviruses. (42 citations)
  • Genetic Characterization and Classification of Human and Animal Sapoviruses. (42 citations)
  • Attempts to grow human noroviruses, a sapovirus, and a bovine norovirus in vitro. (26 citations)

In his most recent research, the most cited papers focused on:

  • Gene
  • DNA
  • Virus

The scientist’s investigation covers issues in Sapovirus, Virology, Genetics, Genome and Polymerase chain reaction. His Sapovirus study improves the overall literature in Genotype. He has researched Genotype in several fields, including GenBank, Outbreak and Capsid.

Norovirus and Viral replication are the primary areas of interest in his Virology study. His Polymerase chain reaction research incorporates themes from Amino acid, Sequence analysis, NS3, Mink and Protein sequencing. The various areas that he examines in his Coding region study include Peptide sequence, Strain, Genetic diversity and Phylogenetics.

Best Publications

  • Coexistence of Multiple Genotypes, Including Newly Identified Genotypes, in Outbreaks of Gastroenteritis Due to Norovirus in Japan

    Tsutomu Kageyama;Michiyo Shinohara;Kazue Uchida;Shuetsu Fukushi

  • Phylogenetic analysis of the complete genome of 18 Norwalk-like viruses.

    Kazuhiko Katayama;Haruko Shirato-Horikoshi;Shigeyuki Kojima;Tsutomu Kageyama

  • Comprehensive Review of Human Sapoviruses

    Tomoichiro Oka;Tomoichiro Oka;Qiuhong Wang;Kazuhiko Katayama;Linda J. Saif

  • Detection of human sapovirus by real-time reverse transcription-polymerase chain reaction

    Tomoichiro Oka;Kazuhiko Katayama;Grant S. Hansman;Tsutomu Kageyama

  • Norovirus Infections in Symptomatic and Asymptomatic Food Handlers in Japan

    Kazuhiro Ozawa;Tomoichiro Oka;Naokazu Takeda;Grant S. Hansman

  • Cell culture isolation and sequence analysis of genetically diverse US porcine epidemic diarrhea virus strains including a novel strain with a large deletion in the spike gene.

    Tomoichiro Oka;Linda J. Saif;Douglas Marthaler;Malak A. Esseili

  • Genetic and antigenic diversity among noroviruses.

    Grant S. Hansman;Katsuro Natori;Haruko Shirato-Horikoshi;Satoko Ogawa

  • Human sapoviruses: genetic diversity, recombination, and classification

    Grant S. Hansman;Tomoichiro Oka;Kazuhiko Katayama;Naokazu Takeda

  • Distribution of phospholipid transfer protein in human plasma: presence of two forms of phospholipid transfer protein, one catalytically active and the other inactive.

    Tomoichiro Oka;Takeshi Kujiraoka;Mayumi Ito;Tohru Egashira

  • Antigenic Relationships among Porcine Epidemic Diarrhea Virus and Transmissible Gastroenteritis Virus Strains

    Chun-Ming Lin;Xiang Gao;Tomoichiro Oka;Anastasia N Vlasova

  • Isolation and partial characterization of the inactive and active forms of human plasma phospholipid transfer protein (PLTP).

    Minna Kärkkäinen;Tomoichiro Oka;Vesa M. Olkkonen;Jari Metso

  • Human sapovirus classification based on complete capsid nucleotide sequences

    Tomoichiro Oka;Tomoichiro Oka;Kohji Mori;Nobuhiro Iritani;Seiya Harada

  • Divergent Evolution of Norovirus GII/4 by Genome Recombination from May 2006 to February 2009 in Japan

    Kazushi Motomura;Masaru Yokoyama;Hirotaka Ode;Hiromi Nakamura

  • Identification of Monomorphic and Divergent Haplotypes in the 2006-2007 Norovirus GII/4 Epidemic Population by Genomewide Tracing of Evolutionary History

    Kazushi Motomura;Tomoichiro Oka;Masaru Yokoyama;Hiromi Nakamura

  • Intergenogroup recombination in sapoviruses.

    Grant S. Hansman;Naokazu Takeda;Tomoichiro Oka;Mitsukai Oseto

  • Prevalence of Porcine Noroviruses, Molecular Characterization of Emerging Porcine Sapoviruses from Finisher Swine in the United States, and Unified Classification Scheme for Sapoviruses

    Kelly A. Scheuer;Tomoichiro Oka;Armando E. Hoet;Wondwossen A. Gebreyes

  • Outbreak of Gastroenteritis Due to Sapovirus

    Grant S. Hansman;Hiroyuki Saito;Chihiro Shibata;Shizuko Ishizuka

  • Two novel missense mutations in the CETP gene in Japanese hyperalphalipoproteinemic subjects: high-throughput assay by Invader assay.

    Makoto Nagano;Shizuya Yamashita;Ken-ichi Hirano;Mayumi Ito

  • A sandwich enzyme-linked immunosorbent assay for human serum paraoxonase concentration.

    Takeshi Kujiraoka;Tomoichiro Oka;Mitsuaki Ishihara;Tohru Egashira

  • Novel recombinant sapovirus.

    Kazuhiko Katayama;Tatsuya Miyoshi;Kiyoko Uchino;Tomoichiro Oka

Frequent Co-Authors

Kazuhiko Katayama
Kazuhiko Katayama Kitasato University
Naokazu Takeda
Naokazu Takeda National Institutes of Health
Grant S. Hansman
Grant S. Hansman Griffith University
Takaji Wakita
Takaji Wakita National Institute of Infectious Diseases
Tetsuya Mizutani
Tetsuya Mizutani Tokyo University of Agriculture and Technology
Hirokazu Kimura
Hirokazu Kimura RMIT University
Tatsuo Miyamura
Tatsuo Miyamura National Institutes of Health
Vesa M. Olkkonen
Vesa M. Olkkonen University of Helsinki
Kwonil Jung
Kwonil Jung The Ohio State University
Tetsuya Hosaka
Tetsuya Hosaka Toranomon Hospital

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