Hai Yan
Gründer bei GENETRON HOLDINGS LIMITED
Aktive Beziehungen
| Name | Geschlecht | Alter | Unternehmensverbindungen | Zusammenarbeit |
|---|---|---|---|---|
| Si Zhen Wang | M | 48 |
Beijing Genetron Biotechnology Co. Ltd.
 Beijing Genetron Biotechnology Co. Ltd. Pharmaceuticals: MajorHealth Technology Beijing Genetron Biotechnology Co. Ltd. provides healthcare solutions. It offers Cancer Genetic Testing, DNA Methylation Sequencing, RNA Sequencing, Whole-Exome Sequencing and Glioma Panel. The company was founded in December 2013 by Si-Zhen Wang and Hai Yan and is headquartered in Beijing, China.
Beijing Genetron Health Gene Technology Co., Ltd.
 Beijing Genetron Health Gene Technology Co., Ltd. Information Technology ServicesTechnology Services Beijing Genetron Health Gene Technology Co. Ltd. provides software development services. It also engages in the import, export and sale of medical equipment. The company was founded on May 7, 2015 and is headquartered in Beijing, China. | 11 Jahre |
| Wei Wu He | M | 59 |
Beijing Genetron Health Gene Technology Co., Ltd.
Beijing Genetron Health Gene Technology Co., Ltd. Information Technology ServicesTechnology Services Beijing Genetron Health Gene Technology Co. Ltd. provides software development services. It also engages in the import, export and sale of medical equipment. The company was founded on May 7, 2015 and is headquartered in Beijing, China.
Beijing Genetron Biotechnology Co. Ltd.
Beijing Genetron Biotechnology Co. Ltd. Pharmaceuticals: MajorHealth Technology Beijing Genetron Biotechnology Co. Ltd. provides healthcare solutions. It offers Cancer Genetic Testing, DNA Methylation Sequencing, RNA Sequencing, Whole-Exome Sequencing and Glioma Panel. The company was founded in December 2013 by Si-Zhen Wang and Hai Yan and is headquartered in Beijing, China. | - |
| Yu Chen Jiao | M | 47 |
Beijing Genetron Health Gene Technology Co., Ltd.
Beijing Genetron Health Gene Technology Co., Ltd. Information Technology ServicesTechnology Services Beijing Genetron Health Gene Technology Co. Ltd. provides software development services. It also engages in the import, export and sale of medical equipment. The company was founded on May 7, 2015 and is headquartered in Beijing, China. | 7 Jahre |
| Barbara Weber | M | 67 |
American Society for Clinical Investigation
 American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Wing Kee Lau | M | 60 | 4 Jahre | |
| Webster Cavenee | M | 73 | 4 Jahre | |
| Dian Kang | M | 76 | 4 Jahre | |
| Steven Patierno | M | 66 |
Duke Cancer Institute
 Duke Cancer Institute Hospital/Nursing ManagementHealth Services Duke Cancer Institute is an organization that unites the academic and clinical communities of Duke University and the Duke University Health System. The non-profit company is based in Durham, NC and has subsidiaries in the United States. The company's main focus is to provide access to technologies, services, and scientific consultation through its Shared Resources. | - |
| John Dipersio | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Raymond P. Warrell | M | 74 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Herbert Virgin | M | 68 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Xu Li | M | - |
Beijing Genetron Health Gene Technology Co., Ltd.
Beijing Genetron Health Gene Technology Co., Ltd. Information Technology ServicesTechnology Services Beijing Genetron Health Gene Technology Co. Ltd. provides software development services. It also engages in the import, export and sale of medical equipment. The company was founded on May 7, 2015 and is headquartered in Beijing, China. | - |
| Raymond DuBois | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Phillip Febbo | M | 57 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | 15 Jahre |
| Bruce S. Bochner | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Christine Seidman | M | 71 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Francisco J. Esteva | M | 60 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Boris Pasche | M | 63 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Zhen Bo Shu | M | - |
Beijing Genetron Health Gene Technology Co., Ltd.
Beijing Genetron Health Gene Technology Co., Ltd. Information Technology ServicesTechnology Services Beijing Genetron Health Gene Technology Co. Ltd. provides software development services. It also engages in the import, export and sale of medical equipment. The company was founded on May 7, 2015 and is headquartered in Beijing, China. | - |
| Xia Wu | F | 43 | 7 Jahre | |
| James Rosenbaum | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Yan Rong Zhao | M | - | - | |
| Yun Fu Hu | M | 62 | 4 Jahre | |
| Chao Tang | M | 66 | 3 Jahre | |
| Craig T. Basson | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Aida Habtezion | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Ying Hong | M | 53 | 8 Jahre | |
| Irma Gigli | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Ce Xu | M | 43 | 6 Jahre | |
| Fatih Uckun | M | 65 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Saptarsi Haldar | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Bruce R. Conklin | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| John Strickler | M | - |
Duke Cancer Institute
Duke Cancer Institute Hospital/Nursing ManagementHealth Services Duke Cancer Institute is an organization that unites the academic and clinical communities of Duke University and the Duke University Health System. The non-profit company is based in Durham, NC and has subsidiaries in the United States. The company's main focus is to provide access to technologies, services, and scientific consultation through its Shared Resources. | - |
| Laurence Turka | M | 66 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | 29 Jahre |
| Jonathan Ravdin | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Hagop Youssoufian | M | 67 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Shan Fu | M | 56 | 3 Jahre | |
| Robert Hubbard | M | 66 |
The Trustees of Columbia University in The City of New York
| 27 Jahre |
| Phillip Gold | M | 83 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Edward Holmes | M | 83 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Adel Mahmoud | M | 82 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | 46 Jahre |
| Margaret Liu | M | 67 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Robert Williams | M | 75 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Joshua Hare | M | 61 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Jorge Plutzky | M | 65 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Art Pappas | M | 76 |
Duke Cancer Institute
Duke Cancer Institute Hospital/Nursing ManagementHealth Services Duke Cancer Institute is an organization that unites the academic and clinical communities of Duke University and the Duke University Health System. The non-profit company is based in Durham, NC and has subsidiaries in the United States. The company's main focus is to provide access to technologies, services, and scientific consultation through its Shared Resources. | - |
| Suzanne Oparil | M | 82 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Ellen Oran Kaden | F | 72 |
The Trustees of Columbia University in The City of New York
| 28 Jahre |
| Robert N. Bontempo | M | 64 |
The Trustees of Columbia University in The City of New York
| 30 Jahre |
| Sabin C. Streeter | M | 82 |
The Trustees of Columbia University in The City of New York
| 27 Jahre |
| Paul Friedman | M | 81 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Dennis A. Carson | M | 77 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Paul Rothman | M | 65 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Karl-Heinz Krause | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Merit Janow | F | 66 |
The Trustees of Columbia University in The City of New York
| 30 Jahre |
| David R. Hathaway | M | 76 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| David Altshuler | M | 59 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Dean Li | M | 62 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| David Drutz | M | 86 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| David H. Cohen | M | 85 |
The Trustees of Columbia University in The City of New York
| 29 Jahre |
| Ronald D. Guttmann | M | 87 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Elizabeth J. Keefer | F | - |
The Trustees of Columbia University in The City of New York
| 27 Jahre |
| Craig Thompson | M | 71 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Lawrence Corey | M | 77 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Dennis K. Stone | M | 72 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Jeffrey Glenn | M | 61 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Jess Gilbert Thoene | M | 81 |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
| Phillip A. Bauman | M | 67 |
The Trustees of Columbia University in The City of New York
| 27 Jahre |
| Kirk Campbell | M | - |
American Society for Clinical Investigation
American Society for Clinical Investigation BiotechnologyHealth Technology American Society for Clinical Investigation engages as a medical honor society. It focuses on physician-scientists in research, clinical care, and medical education. The company was founded by Samuel J. Meltzer in 1908 and is headquartered in Ann Arbor, MI. | - |
Beziehungs-Chart
Beziehungen zu mehreren Unternehmen
Ehemalige Beziehungen
| Name | Geschlecht | Alter | Unternehmensverbindungen | Zusammenarbeit |
|---|---|---|---|---|
| Hank L. Torbert | M | 52 |
The Trustees of Columbia University in The City of New York
| 8 Jahre |
| Thanavut Pornrojnangkool | M | - |
The Trustees of Columbia University in The City of New York
| 12 Jahre |
| Grace Kim | F | - |
The Trustees of Columbia University in The City of New York
| 4 Jahre |
| Hui Ou Yang | M | 52 |
Peking University Health Science Center
| 7 Jahre |
| Hai Tao | M | 53 |
The Trustees of Columbia University in The City of New York
| 5 Jahre |
| Henry Lu | M | 58 |
The Trustees of Columbia University in The City of New York
| 6 Jahre |
| Ke Xiang Zhou | M | 60 |
Peking University Health Science Center
| 6 Jahre |
| James Stone | M | - |
The Trustees of Columbia University in The City of New York
| 10 Jahre |
| Ko Yukawa | M | 58 |
The Trustees of Columbia University in The City of New York
| 2 Jahre |
| Ming Yeung Lau | M | 45 |
The Trustees of Columbia University in The City of New York
| 5 Jahre |
| David Carter | M | - |
The Trustees of Columbia University in The City of New York
| 3 Jahre |
| Daniel Abel Monteiro Palhares Traça | M | 57 |
The Trustees of Columbia University in The City of New York
| 3 Jahre |
| Seth T. Goldsamt | M | - |
The Trustees of Columbia University in The City of New York
| 3 Jahre |
| David Ham | M | - |
The Trustees of Columbia University in The City of New York
| 5 Jahre |
| Bruce Badner | M | - |
The Trustees of Columbia University in The City of New York
| 5 Jahre |
| Jane F. Golden | F | - |
The Trustees of Columbia University in The City of New York
| 1 Jahre |
| Steven Gutterman | M | 55 |
The Trustees of Columbia University in The City of New York
| 5 Jahre |
| Gregory Fairchild | M | 61 |
The Trustees of Columbia University in The City of New York
| 5 Jahre |
| Saurin Dinesh Shah | M | 57 |
The Trustees of Columbia University in The City of New York
| 3 Jahre |
| Len Berman | M | - |
The Trustees of Columbia University in The City of New York
| 4 Jahre |
| Yi Ping Wang | M | - |
The Trustees of Columbia University in The City of New York
| 5 Jahre |
| Susan Y. Choe | F | - |
The Trustees of Columbia University in The City of New York
| 2 Jahre |
| Justin Lu | M | 53 |
The Trustees of Columbia University in The City of New York
| 3 Jahre |
| Chris Paldino | M | 48 |
The Trustees of Columbia University in The City of New York
| 4 Jahre |
| Ari H. Shrage | M | - |
The Trustees of Columbia University in The City of New York
| 6 Jahre |
| Anil Patel | M | - |
The Trustees of Columbia University in The City of New York
| 4 Jahre |
| Fauzia Rashid | F | - |
The Trustees of Columbia University in The City of New York
| 3 Jahre |
| Curt LaBelle | M | 53 |
The Trustees of Columbia University in The City of New York
| 5 Jahre |
| Sherri Scribner | F | - |
The Trustees of Columbia University in The City of New York
| 6 Jahre |
| Ehud A. Gelblum | M | - |
The Trustees of Columbia University in The City of New York
| 5 Jahre |
| Yi Han Fang | F | 51 |
The Trustees of Columbia University in The City of New York
| 3 Jahre |
Statistik
| Land | Beziehungen | % des Gesamten |
|---|---|---|
| Vereinigte Staaten | 83 | 83,00% |
| Cayman Islands | 13 | 13,00% |
| China | 7 | 7,00% |
Alter der Beziehungen
Aktive
Vergangene
Herr
Frau
Aufsichtsräte
Führungskräfte
Ursprung der Beziehungen