Editorial Board

Founder & Editor in Chief
Prof. Gregory J Tsay M.D., Ph.D., FACR

Prof. Gregory J Tsay M.D., Ph.D., FACR
Professor of Medicine & Director
Immunology Research and Development Center
China Medical University (CMU)
Taiwan

  Biography :

Gregory J Tsay is professor of School of Medicine and director, Immunology Research and Development Center, China Medical University Hospital, Taichung, Taiwan. He graduated from Medical School of Chung Shan Medical with M.D. and earned Ph.D. Following a one-year research fellow at Royal North Shore hospital, Sydney, Australia (under the supervision of Dr. David Nelson) and a two-year research fellow at The Scripps Research Institute, La Jolla, USA (under the supervision of Dr. Eng M Tan), He returned to Taiwan to head the division of Rheumatology and Immunology, Chung Shan Medical University Hospital, Taichung, Taiwan. He was appointed as an assistant professor, associated professor, and then full professor in 1990. His main fields of scientific interest are in autoimmune diseases. He is vice-president of Federation of Immunological Society of Asia- Oceania (FIMSA 2015-) and He was president of Taiwan Immunology Society and Taiwan Rheumatolgy Society, and Secretary General of FIMSA.

Biography
  Research Interest :

His main fieldds of scientific interest are in autoimmune diseases.

Research Interest
Editorial Board Member
Dr. Omnia Madgy Mohammed

Dr. Omnia Madgy Mohammed
Assistant Professor of Pharmacology
Faculty of Pharmacy
Jouf University
Saudi Arabia

  Biography :

* 6/2004- 3/2011 Demonstrator of Experimental, Clinical Pharmacology, Faculty of Medicine, Beni-Suef University. * 7/2011 Assistant Lecturer of Experimental, Clinical Pharmacology, Faculty of Medicine, Beni-Suef University. * 2012 Assistant Lecturer of Experimental, Clinical Pharmacology, Faculty of Dentistry, Nahda University. * 2012 Assistant Lecturer of Experimental, Clinical Pharmacology, Faculty of Pharmacy, Nahda University. * 10/2015 Lecturer of Experimental, Clinical Pharmacology, Faculty of Medicine, Beni-Suef University. * 2016 Assistant Professor of Clinical Pharmacology, Faculty of Pharmacy, Al jouf University.

Biography
  Research Interest :

Statistics, Preparing a collage teacher, Ethics of teaching, Methods of medical research, Skills of effective data show, Skills of good thinking, Student evaluation and examination technique, Quality standards in teaching, International publication of research, University management, University legal and financial aspects, Organization of scientific conferences, Toefel and The Eygptian Society of Pharmacology and Experimental Therapeutics "ESPET" as a tutor during the work shop.

Research Interest
Editorial Board Member
Dr. Abbas Mirzaei

Dr. Abbas Mirzaei
Researcher
VALIASR HOSPITAL
ZANJAN
Iran

  Biography :

Dr. Abbas Mirzaei was born in Iran. He had passed the residency period in internal medicine in Tabriz University of Medical School during 2012 – 2016 years. His main work is within an academic hospital in Zanjan University of Medical School as a consultant doctor and ICU care worker. In 2018, Dr. Mirzaei write the article, An Analysis on Pyrin E148Q Mutations in Patients with Refractory Rheumatoid Arthritis. The results of this article showed MEFV gene mutations has no possible roles in RA development. Most of Dr. Mirzaei spare time is taken up with his families or studying medical journals, articles and books. At present he is passing research to publication course of British medical journal (bmj).

Biography
  Research Interest :

Dr. Abbas Mirzaei interest in pulmonology & rheumatology & medical educations

Research Interest
Editorial Board Member
Prof. Marvin Fritzler PhD MD FRCP(C)

Prof. Marvin Fritzler PhD MD FRCP(C)
Professor of Medicine
Cumming School of Medicine
University of Calgary
Canada

  Biography :

Dr. Marvin Fritzler PhD MD FRCP(C) is Professor of Medicine in the Cumming School of Medicine at the University of Calgary. He is the Founder of Mitogen Advanced Diagnostics Laboratory. His research focused on the molecular and cell biology of autoantigens and the induction of autoimmunity by environmental exposures. The spectrum of diagnostic tests based on his discoveries reflect his commitment to knowledge translation. Dr. Fritzler has published more than 400 peer-reviewed manuscripts and his work has been cited more than 14,000 times (H index 51). He has been invited to lecture in international symposia focusing on autoantibodies as biomarkers for predicting, preventing and treating autoimmune diseases, and especially their application to precision medicine. He was appointed to the Government of Alberta’s science, technology and innovation policy and strategy board and in 2005 was appointed as the Chair of the Alberta Research and Innovation Authority. Among his many awards, he was inducted into the BioAlberta Hall of Fame, was awarded the Alberta Centennial Medal and the ASTech Foundation Award in 1996, was inducted as an Honorary Member into the Mexican Academy of Medicine in 2002, was inducted as a Master of the American College of Rheumatology in 2013 and the Order of the University of Calgary in 2014. More recently, he was awarded the American Association of Clinical Chemistry - Carl R Jolliff - Lifetime Achievement Award in 2016, Le Prix Rogers Demers, International Contributions to Rheumatology in 2018 and the Canadian Society Clinical Chemists Research Excellence Award in 2018.

Biography
  Research Interest :

Rheumatology

Research Interest
Editorial Board Member
Dr. Arif Ahmed MD

Dr. Arif Ahmed MD
Consultant
Anesthesia, Critical care and Pain Management
C K Birla Hospital for Women
India

  Biography :

Dr Arif Ahmed has done his MBBS and MD ( Anesthesiology ) from Assam Medical College. After that he has done his senior residency from the prestigious All India Institute of Medical Sciences, New Delhi. He got himself empowered with the knowledge of chronic pain with the fellowship from the prestigious Singapore General Hospital, Singapore. He has also done a end of life mini-fellowship from Stanford University, USA. Presently, working as a consultant in Columbia Asia Hospital, New Delhi in Anesthesia and Pain Management. He is doing excellent work in the field of pain medicine and has done a few innovative works with the use of ultra-sound for the relief of chronic painful conditions and few of which has been published and well acclaimed. He is also involved in the research and also a editorial board member of a few journals.

Biography
  Research Interest :

• Chronic Pain- Radiofrequency ablation, epidural steroid injection, neurolysis, intra-thecal pump, nerve stimulators. • Cancer Pain & Palliative care • Anesthesia in oncological surgeries. • Acute pain management. • Labor analgesia. • Difficult airway management • Research in pain management.

Research Interest
Editorial Board Member
Prof. Jaung-Geng Lin

Prof. Jaung-Geng Lin
Chair Professor
China Medical University

Taiwan

  Biography :

(1) Director, Acupuncture Research Center of China Medicine University (1985-99), Associate Professor (1988-92), Professor (1992-present), Chairperson of the Institute of China Medical Science (1993-95), Chair Professor (2013-present) (2) Adjunct Professor (1997-2014), Institute of Traditional Medicine, National Yang-Ming University. (3) Visiting Professor, The National Victoria University, Australia(1997); Senior Academic Consultant in Chinese Medicine for The Chinese Medicine Unit, RMIT University, Australia(1999-2002) (4) Adjunct Professor, National Taiwan University(1998-99) (5) Visiting Professor, University of Oradea, Romania(2004-present); Visiting Professor, Vasile Goldiș Western University of Arad, Romania(2004-present) (6) Chair Professor, Department of Healthcare Administration, Asia University(2013-present); Chair Professor, School of Post-Baccalaureate Chinese Medicine, Tzu Chi University(2014-present)

Biography
  Research Interest :

Traditional Chinese medicine; acupuncture and moxibustion, Chinese medicine

Research Interest
Editorial Board Member
Prof. Ming-Chi Lu, MD

Prof. Ming-Chi Lu, MD
Professor
Department of Life Science,
National Chung Cheng University
Taiwan

  Biography :

Division of Immunology, Rheumatology and Allergy, Buddhist Dalin Tzu Chi Hospital, No.2, Min-Sheng Road, Dalin Town, Chia-Yi, Taiwan, Chia-Yi, Taiwan 622, R.O.C.

Biography
  Research Interest :

Immunology Research

Research Interest
Editorial Board Member
Prof. Jeng-Hsien Yen, MD, PhD, MSc

Prof. Jeng-Hsien Yen, MD, PhD, MSc
Professor & Chief
Kaohsiung Medical University
Division of Rheumatology Department of Internal Medicine
Taiwan

  Biography :

Dr. Jeng-Hsien Yen received his MD, MSc, and PhD from Kaohsiung Medical University in Taiwan. He was trained as a resident in Kaohsiung Medical University Hospital. He had been a postdoctoral fellow at Rheumatology Lab of Mayo Clinic in Rochester, Minnesota. He has been a professor of Kaohsiung Medical University since 2002. He was the Dean of College of Medicine, Dean of College of Medicine, Kaohsiung Medical University (2012- 2018). Now he is a professor at Graduate Institute of Clinical Medicine and the chief of Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital.

Biography
  Research Interest :

Genetics and epigenetics of rheumatic diseases

Research Interest
Editorial Board Member
Dr. Chi-Chiu MOK (MD, FRCP)

Dr. Chi-Chiu MOK (MD, FRCP)
Chief of the Division of Rheumatology
Department of Medicine
Tuen Mun Hospital
Hong Kong

  Biography :

Dr. Mok is currently the chief of the Division of Rheumatology, Department of Medicine, Tuen Mun Hospital, Hong Kong. He is a consultant physician and honorary teaching professor of the Chinese University of Hong Kong. Dr. Mok serves as the program director of the Rheumatology / Immunology accreditation board of the Hong Kong College of Physicians.

Biography
  Research Interest :

Dr. Mok is currently the senior associate editor of the International Journal of Rheumatic Diseases and an editorial member of the Journal of Rheumatology, Current Rheumatology Review, Open Orthopedic Journal and Immunology and Immunogenetic Insights. In addition, he is an ad-hoc reviewer of more than 60 medical and rheumatology journals. Dr. Mok is a Past President of the Hong Kong Society of Rheumatology. He is the founder editor of the Hong Kong Bulletin on Rheumatic Diseases, the official publication of the Hong Kong Society of Rheumatology.

Research Interest
Editorial Board Member
Prof. Zhanguo Li, MD, PhD

Prof. Zhanguo Li, MD, PhD
Professor of Rheumatology,
Chief, Department of Rheumatology and Immunity
Medical School of Peking University
China

  Biography :

Professor Zhanguo Li obtained his medical degree from the First Millitary Medical University, China, followed by postgraduate training at the Faculty of Medicine, University of Sydney. He then worked as a Research Fellow in Immunopathology at Dana-Farber Institute, Harvard University Medical School prior to his current role at Peking University Medical School. Professor Li is the President of Clinical Immunology Association of China, the Honorary President of Chinese Rheumatology Association (CRA), the Past President of Asian and Pacific League Against Rheumatism (APLAR). He is also the Past President of International League of Associations for Rheumatology (ILAR). He is currently the Associate Editor of Clinical Rheumatology, and Associate Editor of International Journal of Rheumatic Disease, the Chief Editor of Chinese Journal of Rheumatology, and the Chief Editor of Chinese Journal of Clinical Immunology and Rheumatology. In addition, he serves on the editorial boards of Nat Rev Rheum, Ann Rheum Dis, Curr Opin Rheum, and Clin Exp Rheum. He has published over 500 articles on peer reviewed journals, e.g. Nat Med, Nat Genet, Immunity, Cell H&M, Ann Internal Med, Nat Rev Rheum, and Ann Rheum Dis. He has contributed as Chief-Editor or author to over 30 textbooks and book chapters in Rheumatology and Immunology.

Biography
  Research Interest :

He is the founder of International Forum of Rheumatoid arthritis which has been held annually since 2009. He has received a number of national and international acclaim for his dedication to rheumatology. Professor Li played a leading role in development of classification criteria for early rheumatoid arthritis (ERA), and in establishing of a diagnostic model for Sjögren's syndrome (SS) by novel biomarkers. He developed by using low-dose IL2, small-pulse of cyclophasphamide and T cell vaccine treatment of SLE, and the PRINT strategy for high remission in RA.

Research Interest
Editorial Board Member
Prof. Ping-Ning Hsu, MD, PhD.

Prof. Ping-Ning Hsu, MD, PhD.
Professor
Graduate Institute of Immunology College of Medicine
National Taiwan University
Taiwan

  Biography :

Professional Societies: American Association of Immunologists Chinese Society of Immunology Taiwan Rheumatology Society

Biography
  Research Interest :

Microbiology, Immunology and Infection, Rheumatology

Research Interest
Editorial Board Member
Dr. Mir Nadeem

Dr. Mir Nadeem
Senior Resident
Shree guru gobind tricentenary (SGT) medical college
Gurgaon
India

  Biography :

As a highly motivated and patient oriented doctor, recently completed my post graduation and working as registrar Internal Medicine with hands on ex-perience in dealing with patients in the emergency and both OPD and inpatient departments from all medical departments. Seeking to enrich my clinical skills, inculcate holistic patient care, and learn newer research techniques particularly in the field of critical care and gain a plethora of personal experience which would help me gain more self aware-ness.

Biography
  Research Interest :

o Rheumatological disorders particularly Rheumatoid ,SLE etc o gastroenterology and hepatology particularly autoimmune hepatitis and IBD o o cardiology ,interventional cardiology

Research Interest
Editorial Board Member
Prof. Edward K.L. Chan, Ph.D.

Prof. Edward K.L. Chan, Ph.D.
Professor
Department of Oral Biology
University of Florida, Health Science Center
USA

  Biography :

Dr. Edward K.L. Chan obtained his Bachelor in Biochemistry from the University of British Columbia, M.Sc. in Clinical Chemistry and Ph.D. in Medical Science and Immunopathology from the University of Calgary, respectively. It was during his postdoctoral training in the laboratory of Professor Eng M. Tan at the Scripps Research Institute, La Jolla, California, that he developed lifelong interests in the biological significance of autoantibodies in patients with systemic rheumatic diseases and cancers. His early work focused on the study of human autoantibodies and autoantigens in systemic lupus erythematosus and Sjögren’s syndrome including the characterization of SS-B/La and the initial identification and cloning of the Ro52/TRIM21 autoantigen. His laboratory has been highly successful in using unique autoimmune antibodies as probes to identify and clone a number of interesting macromolecular self-antigens. These include the ribosomal RNA transcription factor NOR90/hUBF localized to the nucleolar organizer region on mitotic chromosomes; p80-coilin, the primary marker for the Cajal body; a coiled-coil-rich protein family of Golgi autoantigens known as golgins; and GW182, a marker protein for cytoplasmic foci GW bodies. In 2002, Dr. Chan moved to the University of Florida, Gainesville, FL, as Professor in Department of Oral Biology and Department of Anatomy and Cell Biology. Dr. Chan’s research interests continue in autoantigens and autoantibodies.

Biography
  Research Interest :

Professor Chan’s lab has been highly successful in using autoimmune antibodies to identify and clone a number of interesting self-antigens. These include SS-B/La; Ro52/TRIM21; the ribosomal RNA transcription factor NOR90/hUBF; p80-coilin of the Cajal body; coiled-coil-rich Golgi proteins known as golgins; and GW182, a marker for cytoplasmic foci GW bodies. A new research area is the identification of novel rod/ring structures that are targets of autoantibodies in patients with hepatitis C infection and undergone interferon/ribavirin therapy. These structures are observed in conditions requiring increased GTP biosynthesis in all mammalian cells examined to date. His lab has also published extensively in microRNA function in innate immunity, autoimmune diseases, and oral cancer.

Research Interest
Editorial Board Member
Prof. Ming-Chi Lu, MD

Prof. Ming-Chi Lu, MD
Professor
Division of Immunology, Rheumatology and Allergy
Buddhist Dalin Tzu Chi Hospital
Taiwan

  Biography :

• 2008-2012 Vice-director, Department of Medical Research, Buddhist Dalin Tzu Chi Hospital • 2012 Director, Department of Medical Research, Buddhist Dalin Tzu Chi Hospital • 2018 Chief of Clinical Pathology, Buddhist Dalin Tzu Chi Hospital

Biography
  Research Interest :

Rheumatoid arthritis, especially for the ACPAs in its immunopathogenesis. Aberrant expression of non-coding RNAs in T cells from patients with RA, SLE or AS. Epidemiologic studies of rheumatic diseases using claim data base.

Research Interest
Editorial Board Member
Prof. Der-Yuan Chen (M.D, Ph.D.)

Prof. Der-Yuan Chen (M.D, Ph.D.)
Professor & Vice Superintendent
Rheumatology and Immunology Center
China Medical University Hospital
Taiwan

  Biography :

Der-Yuan Chen (M.D, Ph.D.) is the Vice Superintendent of Rheumatology and Immunology Center, China Medical University Hospital, Taiwan. He is also the professor of Medicine, China Medical University, Taiwan.

Biography
  Research Interest :

In the past 15 years, the Dr. Chen’s Lab has focused on research related to rheumatology, immunogenetics, and molecular immunology. The research directions mainly include: I. Insights into the immunopathogenesis of autoimmune dieases (SLE, RA, dermatomyositis/polymyositis, and Sjögren’s syndrome) or autoinflammatory disease (adult-onset Still’s disease), II. Identification of potential biomarkers in the diagnosis of rheuamtic diseases, III. Investigation of clinical implication or safety profile of therapies with biologics or small molecular inhibitors. In the recent one year, Dr. Chen’s Lab. also has a study regarding stem cell therapy on disease animal models. In the recent 15 years, more than 150 articles related to rheumatic diseases have been published.

Research Interest
Editorial Board Member
Prof. Wan-Wan Lin

Prof. Wan-Wan Lin
Distinguished Professor/Director
Pharmacology; College of Medicine
National Taiwan University
Taiwan

  Biography :

Director (Department of Pharmacology, College of Medicine, National Taiwan University) Director (Graduate Institute of Medical Science, Taipei Medical University) (Temporal appointment) Distinguish Professor (Department of Pharmacology, National Taiwan University, College of Medicine) Visiting Scientist (Burnham Institute for Medical Research, San Diego) Visiting Scientist (University of San Diego) Professor (Department of Pharmacology, National Taiwan University, College of Medicine) Post doc (Stanford University, CA, USA) Associate professor (Department of Pharmacology, National Taiwan University, College of Medicine) 2015/2-present 2012/4-2015/1 2006/8-present 2009/1-2009/6 (Innate Immunity and Cell Death Control 2005/8-2006/7 (Pharmacology) 1998/8--present 1993/3-1994/2 (Pharmacology) 1991/8-1998/7

Biography
  Research Interest :

Innate Immunity, Pattern Recognition Receptors, Inflammation, Inflammasome, Cell Death, Signal Transduction, Mitochondria, Cytokines

Research Interest
Editorial Board Member
Prof. Rong-Sen Yang

Prof. Rong-Sen Yang
Professor and Chairman
Department of Orthopaedics, College of Medicine
National Taiwan University Hospital
Taiwan

  Biography :

Professor Rong-Sen Yang is the Director of the Department of Orthopaedics at the National Taiwan University Hospital, Taipei, Taiwan. He obtained the MD and PhD from the College of Medicine, National Taiwan University, and was awarded a post-doctoral fellowship at the University of California, Los Angeles, United States of America. Professor Yang is the current President of the Taiwan Maple Orthopaedics Association and the immediate past president of the Taiwanese Osteoporosis Association. He is active in a number of national and international associations including the past president of Taiwan Orthopedics Research Society, council member of Taiwan Orthopaedic Association, council member of Formosa Association of Regenerative Medicine, full faculty of International Society of Clinical Densitometry, National delegate of Asia-Pacific Musculoskeletal Tumor Society, member of the International Society of Limb Salvage, the Orthopaedic Research Society and the American Society for Bone and Mineral Research. He has authored and co-authored more than 200 peer-reviewed articles, book chapters, guidelines and reviews in the field of osteoporosis, bone metastases and orthopedics.

Biography
  Research Interest :

His research interests include musculoskeletal health and diseases; osteoporosis; physical therapy aspects of osteoporosis in men; osteoporosis drug discovery; bone cell biology; arthritis biology; as well as orthopedics oncology.

Research Interest
Editorial Board Member
Prof. Fu-Tong Liu, M.D., Ph.D.

Prof. Fu-Tong Liu, M.D., Ph.D.
Professor & Vice President
Academia Sinica
Taipei
Taiwan

  Biography :

Dr. Fu-Tong Liu is currently Vice President of Academia Sinica, Taiwan. He received his BS degree in Chemistry from National Taiwan University, PhD degree in Chemistry from University of Chicago, and MD degree from University of Miami. He served as Head of the Allergy Research Section at the Scripps Research Institute, Head of the Division of Allergy at La Jolla Institute for Allergy and Immunology, and Distinguished Professor and Chair at Department of Dermatology, University of California-Davis. He became Distinguished Research Fellow and Director at Institute of Biomedical Sciences, Academia Sinica, in 2010 and was appointed Vice President of the organization in 2016. He has published over 340 original scientific papers and review articles. His papers have been cited over 27,000 times and his h-index is 90 (Google Scholar). He is on the editorial board of a number of journals, including Glycobiology. He is a Fellow of American Association for the Advancement of Science (AAAS) and Academician of Academia Sinica. He was First Laureate of the 2015 Khwarizmi International Award.

Biography
  Research Interest :

Dr. Liu contributed to the identification of the family of animal lectins galectins, and his research is focused on the roles of these proteins in inflammation and immunity, as well as cancer progression and adiposity.

Research Interest
Editorial Board Member
Dr. Md. Monoarul Haque

Dr. Md. Monoarul Haque
Assistant Professor
Department of Public Health
Fareast International University
Bangladesh

  Biography :

Md Monoarul Haque was born in Dhaka, Bangladesh. He has done PhD under Faculty of Medical Studies in Bangladesh University of Professionals (BUP). He got NOMA Grant from University of Oslo, Norway for research. Besides he got one year teaching & research fellowship Funded by USAID Developing Next Generation of Public Health Experts Project (NGPHEP). He is a member of Geneva Foundation for Medical Education and Research. He has number of publications in International Open Access peer reviewed index journals. As a young scientist he is expert on editorial writing also and already lot of editorial has been published. At present he is working as Assistant Professor, Department of Public Health, Fareast International University.

Biography
  Research Interest :

Community nutrition, Ethnic nutrition, Pre-school nutrition

Research Interest
Editorial Board Member

Prof. K Satya Kumar
Professor
Orthopaedics
Nri Academy Of Sciences
India

  Biography :

F I A S & F I T Fellowship In Arthroplasty Surgery : :Cantonal Hospital, Fribourg,Switzerland Fellowship In Traumatology: :Cantonal Hospital, Fribourg,Switzerland August 2016

Biography
  Research Interest :

As Professor & Associate Professor, I Am Involved In Presenting Seminars/Cases At Departmental Meetings And In Teaching Programs For Orthopaedic Residents And Post Graduate Students. I Was The Teaching Programme Co Coordinator In The Department Of Orthopedics, Psims, Gannavaram, Andhrapradesh, India

Research Interest
Editorial Board Member
Dr. S. S. Jha

Dr. S. S. Jha
Head of Department
Department of Orthopaedics, Orthopaedic Rheumatology & Joint Replacement Surgery
Mahavir Vaatsalya Aspatal
India

  Biography :

• Patron and Founder President, Indian Orthopaedic Rheumatology Association • Director, Mahavir Vaatsalya Aspatal, Patna, Bihar, India • Head, Department of Orthopaedics, Orthopaedic Rheumatology & Joint Replacement Surgery, Mahavir Vaatsalya Aspatal, Patna • Teaching experience of 30 years in various medical colleges of Bihar, India • Vice Secretary General, Asia-Pacific Society for Foot & Ankle Surgery • Past President, Indian Foot and Ankle Society

Biography
  Research Interest :

Orthopaedics, Rheumatology

Research Interest
Editorial Board Member
Prof. Manish Khanna

Prof. Manish Khanna
Professor
President Emeritus
Indian Orthopaedic Rheumatology Association
India

  Biography :

Dr Khanna Prof Orthopaedics is a former Sr Consultant Sanjay Gandhi Post Graduate Instute Lucknow . He previously Charter Secretary General is now President Emeritus, Indian Orthopaedic Rheumatology Association and also Founder President of Indian stem cell study Group. Presently attached as Prof & Head ,Hind Medical college,Lucknow and as Director , Apley Orthopaedic Centre, Lucknow. . He is also advisor for stem cell research to few Indian Priemier research Organizations & for past five years working on stem cell / cellular therapy in various orthopaedic conditions. Trained in Paeditrics Orthopaedics specially in Foot & Ankle Deformity correction and Regenerative science in Cerebral Palsy

Biography
  Research Interest :

Foot and Ankle surgery

Research Interest