World's Best Scientists 2026 revealed!
VIEW LIST
Peter J. Mohler

D-Index & Metrics

Biology and Biochemistry

D-Index
77
Citations
20406
World Ranking
4796
National Ranking
2317

Peter J. Mohler 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 Peter J. Mohler 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: 335 publications — 84th percentile

84% of scientists in this discipline score the same or lower.

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

Peter J. Mohler 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 Peter J. Mohler 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: 77 D-Index — 76th percentile

76% of scientists in this discipline score the same or lower.

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

Overview

Peter J. Mohler is affiliated with The Ohio State University in the United States and has contributed extensively to the fields of medicine, biochemistry, genetics, and molecular biology. Their research primarily focuses on cardiology and cardiovascular medicine, with notable work in cardiac electrophysiology and arrhythmias, cardiac fibrosis and remodeling, and ion channel regulation and function.

Mohler's recent publications cover topics related to COVID-19 and cardiac physiology, reflecting a multidisciplinary approach. Selected recent papers include:

  • Neutralization of the SARS-CoV-2 Omicron BA.4/5 and BA.2.12.1 Subvariants, 2022, New England Journal of Medicine
  • Neutralization of SARS-CoV-2 Omicron sub-lineages BA.1, BA.1.1, and BA.2, 2022, Cell Host & Microbe
  • Neutralization and Stability of SARS-CoV-2 Omicron Variant, 2021, bioRxiv (Cold Spring Harbor Laboratory)
  • MicroRNA Biophysically Modulates Cardiac Action Potential by Direct Binding to Ion Channel, 2021, Circulation
  • Impaired neuronal sodium channels cause intranodal conduction failure and reentrant arrhythmias in human sinoatrial node, 2020, Nature Communications

Frequent coauthors in Mohler's publications include:

  • Thomas J. Hund
  • Vadim V. Fedorov
  • Xianyao Xu
  • Bryan A. Whitson
  • Anuradha Kalyanasundaram

Common publication venues where Mohler's work appears are:

  • Circulation
  • Heart Rhythm
  • Circulation Research
  • bioRxiv (Cold Spring Harbor Laboratory)
  • Circulation Arrhythmia and Electrophysiology

Mohler's research spans several specialized subfields:

  • Cardiology and Cardiovascular Medicine
  • Molecular Biology
  • Infectious Diseases
  • Cancer Research
  • Surgery

The main topics of Mohler's scientific work cover:

  • Cardiac electrophysiology and arrhythmias
  • Cardiac Fibrosis and Remodeling
  • Ion channel regulation and function
  • SARS-CoV-2 and COVID-19 Research
  • MicroRNA in disease regulation
  • Cardiac Arrhythmias and Treatments
  • Cardiomyopathy and Myosin Studies

Overall, Mohler's research addresses key mechanisms underlying cardiac function and disease along with emerging infectious threats such as COVID-19, integrating molecular biology techniques with clinical cardiovascular investigations.

Best Publications

  • Ankyrin-B mutation causes type 4 long-QT cardiac arrhythmia and sudden cardiac death

    Peter J. Mohler;Jean-Jacques Schott;Anthony O. Gramolini;Keith W. Dilly

  • A dynamic pathway for calcium-independent activation of CaMKII by methionine oxidation

    Jeffrey R. Erickson;Mei ling A. Joiner;Xiaoqun Guan;William Kutschke

  • FKBP12.6 Deficiency and Defective Calcium Release Channel (Ryanodine Receptor) Function Linked to Exercise-Induced Sudden Cardiac Death

    Xander H T Wehrens;Stephan E. Lehnart;Fannie Huang;John A. Vest

  • Nav1.5 E1053K mutation causing Brugada syndrome blocks binding to ankyrin-G and expression of Nav1.5 on the surface of cardiomyocytes

    Peter J. Mohler;Ilaria Rivolta;Carlo Napolitano;Guy LeMaillet

  • CaMKII determines mitochondrial stress responses in heart

    Mei Ling A. Joiner;Olha M. Koval;Jingdong Li;Jingdong Li;B. Julie He

  • A cardiac arrhythmia syndrome caused by loss of ankyrin-B function

    Peter J. Mohler;Igor Splawski;Carlo Napolitano;Georgia Bottelli

  • Atrial fibrillation driven by micro-anatomic intramural re-entry revealed by simultaneous sub-epicardial and sub-endocardial optical mapping in explanted human hearts.

    Brian J. Hansen;Jichao Zhao;Thomas A. Csepe;Brandon T. Moore

  • Inherited Arrhythmias A National Heart, Lung, and Blood Institute and Office of Rare Diseases Workshop Consensus Report About the Diagnosis, Phenotyping, Molecular Mechanisms, and Therapeutic Approaches for Primary Cardiomyopathies of Gene Mutations Affecting Ion Channel Function

    Stephan E. Lehnart;Michael J. Ackerman;D. Woodrow Benson;Ramon Brugada

  • Ankyrin-B Coordinates the Na/K ATPase, Na/Ca Exchanger, and InsP3 Receptor in a Cardiac T-Tubule/SR Microdomain

    Peter J Mohler;Jonathan Q Davis;Vann Bennett

  • A βIV-spectrin/CaMKII signaling complex is essential for membrane excitability in mice

    Thomas J. Hund;Olha M. Koval;Jingdong Li;Patrick J. Wright

  • A distal axonal cytoskeleton forms an intra-axonal boundary that controls axon initial segment assembly.

    Mauricio R. Galiano;Smita Jha;Tammy Szu-Yu Ho;Chuansheng Zhang

  • Oxidation of CaMKII determines the cardiotoxic effects of aldosterone

    B. Julie He;Mei Ling A. Joiner;Madhu V. Singh;Elizabeth D. Luczak

  • RETRACTED: L-Type Ca2+ Channel Facilitation Mediated by Phosphorylation of the β Subunit by CaMKII

    Chad E. Grueter;Sunday A. Abiria;Igor Dzhura;Yuejin Wu

  • Reduced heterogeneous expression of Cx43 results in decreased Nav1.5 expression and reduced sodium current that accounts for arrhythmia vulnerability in conditional Cx43 knockout mice.

    John A. Jansen;Maartje Noorman;Hassan Musa;Mèra Stein

  • Defining the Cellular Phenotype of “Ankyrin-B Syndrome” Variants Human ANK2 Variants Associated With Clinical Phenotypes Display a Spectrum of Activities in Cardiomyocytes

    Peter J. Mohler;Solena Le Scouarnec;Isabelle Denjoy;John S. Lowe

  • Oxidized CaMKII causes cardiac sinus node dysfunction in mice

    Paari Dominic Swaminathan;Anil Purohit;Siddarth Soni;Niels Voigt;Niels Voigt

  • Phosphorylation of the ryanodine receptor mediates the cardiac fight or flight response in mice.

    Jian Shan;Alexander Kushnir;Matthew J. Betzenhauser;Steven Reiken

  • Sodium current deficit and arrhythmogenesis in a murine model of plakophilin-2 haploinsufficiency.

    Marina Cerrone;Maartje Noorman;Maartje Noorman;Xianming Lin;Halina Chkourko

  • Yes-Associated Protein 65 Localizes P62c-Yes to the Apical Compartment of Airway Epithelia by Association with Ebp50

    Peter J. Mohler;Silvia M. Kreda;Richard C. Boucher;Marius Sudol

  • Voltage-gated Nav channel targeting in the heart requires an ankyrin-G–dependent cellular pathway

    John S. Lowe;Oleg Palygin;Naina Bhasin;Thomas J. Hund

Frequent Co-Authors

Mark E. Anderson
Mark E. Anderson Johns Hopkins University
Vann Bennett
Vann Bennett Duke University
Matthew N. Rasband
Matthew N. Rasband Baylor College of Medicine
Douglas R. Spitz
Douglas R. Spitz University of Iowa
Xander H.T. Wehrens
Xander H.T. Wehrens Baylor College of Medicine
Silvia G. Priori
Silvia G. Priori University of Pavia
Donald M. Bers
Donald M. Bers University of California, Davis
Robert M. Weiss
Robert M. Weiss University of Iowa
Gianrico Farrugia
Gianrico Farrugia Mayo Clinic
Eric Boerwinkle
Eric Boerwinkle The University of Texas Health Science Center at Houston

External Links

Personal website of Peter J. Mohler

If you think any of the details on this page are incorrect, let us know.

Report an issue

We appreciate your kind effort to assist us to improve this page, it would be helpful providing us with as much detail as possible in the text box below:

Best Scientists Citing Peter J. Mohler

Xander H.T. Wehrens

Xander H.T. Wehrens

Baylor College of Medicine

Publications: 95

Michael J. Ackerman

Michael J. Ackerman

Mayo Clinic

Publications: 81

Silvia G. Priori

Silvia G. Priori

University of Pavia

Publications: 73

Donald M. Bers

Donald M. Bers

University of California, Davis

Publications: 72

Arthur A.M. Wilde

Arthur A.M. Wilde

University of Amsterdam

Publications: 67

Mark E. Anderson

Mark E. Anderson

Johns Hopkins University

Publications: 66

Andrew R. Marks

Andrew R. Marks

Columbia University

Publications: 65

Stanley Nattel

Stanley Nattel

Montreal Heart Institute

Publications: 64

Dobromir Dobrev

Dobromir Dobrev

University of Duisburg-Essen

Publications: 59

Vann Bennett

Vann Bennett

Duke University

Publications: 55

Matthew N. Rasband

Matthew N. Rasband

Baylor College of Medicine

Publications: 45

Charles Antzelevitch

Charles Antzelevitch

Lankenau Institute for Medical Research

Publications: 40

Edward G. Lakatta

Edward G. Lakatta

National Institutes of Health

Publications: 39

Carlo Napolitano

Carlo Napolitano

University of Pavia

Publications: 38

José Jalife

José Jalife

University of Michigan–Ann Arbor

Publications: 37

Dan M. Roden

Dan M. Roden

Vanderbilt University Medical Center

Publications: 36

Trending Scientists

Peng Zhou

Peng Zhou

Fudan University

Virginia Walbot

Virginia Walbot

Stanford University

Didier Lacombe

Didier Lacombe

University of Bordeaux

Carol Wagstaff

Carol Wagstaff

University of Reading

Junya Suehiro

Junya Suehiro

Kyushu University

William D. Marslen-Wilson

William D. Marslen-Wilson

University of Cambridge

Paul J. Eslinger

Paul J. Eslinger

Penn State Milton S. Hershey Medical Center

Kirstin Krüger

Kirstin Krüger

University of Oslo

Jian-Dong Jiang

Jian-Dong Jiang

Peking Union Medical College Hospital

Masahiro Nishijima

Masahiro Nishijima

Showa Pharmaceutical University

John D. Mountz

John D. Mountz

University of Alabama at Birmingham

Patrick Pérez

Patrick Pérez

Kyutai

Abdu I. Alayash

Abdu I. Alayash

US Food and Drug Administration

Johan F.M. Swinnen

Johan F.M. Swinnen

International Food Policy Research Institute

Robert O. Bonow

Robert O. Bonow

Northwestern University

Hansjörg Albrecher

Hansjörg Albrecher

University of Lausanne

Related Biology and Biochemistry Rankings & Guides

2026 Best Online Bachelor’s Degrees in Nutritional Science Programs

2026 Best Online Bachelor’s Degrees in Nutritional Science Programs
2026 How Much Does a Pharmacy Degree Program Cost? Tuition, Fees & Total Expense Breakdown

2026 How Much Does a Pharmacy Degree Program Cost? Tuition, Fees & Total Expense Breakdown
2026 Is a Care Coordination Online Degree Worth It?

2026 Is a Care Coordination Online Degree Worth It?
2026 Fastest Online Pediatric Care Nurse Practitioner Degree Programs You Can Finish in Under 2 Years

2026 Fastest Online Pediatric Care Nurse Practitioner Degree Programs You Can Finish in Under 2 Years
2026 How Fast Can You Get a Nutrition Degree Online?

2026 How Fast Can You Get a Nutrition Degree Online?
2026 Admission Requirements for Family Nurse Practitioner Degree Programs

2026 Admission Requirements for Family Nurse Practitioner Degree Programs
2026 Is a Healthcare Administration Online Degree Worth It?

2026 Is a Healthcare Administration Online Degree Worth It?
2026 How Fast Can You Get a Biology Degree Online?

2026 How Fast Can You Get a Biology Degree Online?
2026 Diagnostic Medical Sonographer vs. Registered Nurse: Explaining the Difference

2026 Diagnostic Medical Sonographer vs. Registered Nurse: Explaining the Difference
2026 Radiology Technologist vs. Ultrasound Technologist: Explaining the Difference

2026 Radiology Technologist vs. Ultrasound Technologist: Explaining the Difference
2026 What Prerequisites Do You Need for a Public Health Degree? Entry Requirements, Credits & Eligibility Rules

2026 What Prerequisites Do You Need for a Public Health Degree? Entry Requirements, Credits & Eligibility Rules
2026 Can You Get Into a Psychiatric Mental Health Nurse Practitioner Program with a Low GPA? Admission Chances & Workarounds

2026 Can You Get Into a Psychiatric Mental Health Nurse Practitioner Program with a Low GPA? Admission Chances & Workarounds
2026 MSN vs. NP Nursing Degrees: Explaining the Difference

2026 MSN vs. NP Nursing Degrees: Explaining the Difference
2026 Cheapest and Shortest Online Ultrasound Technology Degree Programs That Pay Well: Cost, Duration, and Salary Outlook

2026 Cheapest and Shortest Online Ultrasound Technology Degree Programs That Pay Well: Cost, Duration, and Salary Outlook
2026 Online Psychiatric Mental Health Nurse Practitioner Degree Programs Costs: Tuition & Fees

2026 Online Psychiatric Mental Health Nurse Practitioner Degree Programs Costs: Tuition & Fees
2026 Cheapest and Shortest Online Dental Assistant Degree Programs That Pay Well: Cost, Duration, and Salary Outlook

2026 Cheapest and Shortest Online Dental Assistant Degree Programs That Pay Well: Cost, Duration, and Salary Outlook
2026 How to Become an ER Tech: Education, Salary, and Job Outlook

2026 How to Become an ER Tech: Education, Salary, and Job Outlook
2026 Online Family Nurse Practitioner Degree Master's Programs That Accept Transfer Credits

2026 Online Family Nurse Practitioner Degree Master's Programs That Accept Transfer Credits
2026 Can You Get a Speech Pathology Degree Master's Without a Related Bachelor's Degree?

2026 Can You Get a Speech Pathology Degree Master's Without a Related Bachelor's Degree?
2026 Medical Assisting Degree vs. Certificate: Which Should You Choose?

2026 Medical Assisting Degree vs. Certificate: Which Should You Choose?
2026 Fastest Online Nutrition Degree Programs You Can Finish in Under 2 Years

2026 Fastest Online Nutrition Degree Programs You Can Finish in Under 2 Years

Recently Published Articles

2026 How to Become a Marriage and Family Therapist (MFT) in Cleveland, OH: License Requirements & Salary

2026 How to Become a Marriage and Family Therapist (MFT) in Cleveland, OH: License Requirements & Salary
2026 Taxation Degree Coursework Explained: What Classes Can You Expect to Take?

2026 Taxation Degree Coursework Explained: What Classes Can You Expect to Take?
2026 Most Affordable Online Education Degrees

2026 Most Affordable Online Education Degrees
2026 Engineering Technology Degree Oversupply or Undersupply? Student Volume vs Employer Demand

2026 Engineering Technology Degree Oversupply or Undersupply? Student Volume vs Employer Demand
2026 Shortest Online Political Science Degree Master's Programs That Pay Well: Cost, Time to Completion, and Salary Outlook

2026 Shortest Online Political Science Degree Master's Programs That Pay Well: Cost, Time to Completion, and Salary Outlook
2026 Online Nutrition Degree Programs for Veterans: GI Bill Benefits, Costs & Top Considerations

2026 Online Nutrition Degree Programs for Veterans: GI Bill Benefits, Costs & Top Considerations
2026 Business Law Degree vs. Certificate: Which Should You Choose?

2026 Business Law Degree vs. Certificate: Which Should You Choose?
2026 Industrial Design Career Outcomes by Degree Level Report: Pay, Employment, and Advancement Patterns

2026 Industrial Design Career Outcomes by Degree Level Report: Pay, Employment, and Advancement Patterns
2026 Cheapest and Shortest Online Reading & Literacy Degree Programs That Pay Well: Cost, Duration, and Salary Outlook

2026 Cheapest and Shortest Online Reading & Literacy Degree Programs That Pay Well: Cost, Duration, and Salary Outlook
2026 Most In-Demand Bioinformatics Master's Specializations

2026 Most In-Demand Bioinformatics Master's Specializations
2026 Best Online Theology Degree Programs

2026 Best Online Theology Degree Programs
2026 Military-Friendly Online Criminal Justice Bachelor's Degree Programs

2026 Military-Friendly Online Criminal Justice Bachelor's Degree Programs
2026 Information Technology Career Hotspots: Cities With the Best Pay, Job Openings, and Growth

2026 Information Technology Career Hotspots: Cities With the Best Pay, Job Openings, and Growth
2026 AI Bachelor's Degree Programs That Offer Laptop Loaner Programs

2026 AI Bachelor's Degree Programs That Offer Laptop Loaner Programs
2026 Graduate Assistantships for Speech Pathology Students: What to Know

2026 Graduate Assistantships for Speech Pathology Students: What to Know
2026 Best Online Pharmacy Technician Associate Programs

2026 Best Online Pharmacy Technician Associate Programs
2026 Best Online Public Administration Degree Master's Programs for Working Professionals

2026 Best Online Public Administration Degree Master's Programs for Working Professionals
2026 Certified Nurse Aide (CNA) License Education Requirements in Virginia

2026 Certified Nurse Aide (CNA) License Education Requirements in Virginia
2026 Cheapest Online Computer Science Bachelor's Degrees That Pay Well: Tuition, Duration, and Earnings

2026 Cheapest Online Computer Science Bachelor's Degrees That Pay Well: Tuition, Duration, and Earnings
2026 Most Affordable Online Environmental Engineering Degree Programs

2026 Most Affordable Online Environmental Engineering Degree Programs
2026 Online Medical Billing & Coding Degree Programs for Veterans: GI Bill Benefits, Costs & Top Considerations

2026 Online Medical Billing & Coding Degree Programs for Veterans: GI Bill Benefits, Costs & Top Considerations