Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Jeffrey P. Jacobs is active.

Publication


Featured researches published by Jeffrey P. Jacobs.


The New England Journal of Medicine | 2010

Comparison of shunt types in the Norwood procedure for single-ventricle lesions.

Richard G. Ohye; Lynn A. Sleeper; Lynn Mahony; Jane W. Newburger; Gail D. Pearson; Minmin Lu; Caren S. Goldberg; Sarah Tabbutt; Peter C. Frommelt; Nancy S. Ghanayem; Peter C. Laussen; John F. Rhodes; Alan B. Lewis; Seema Mital; Chitra Ravishankar; Ismee A. Williams; Carolyn Dunbar-Masterson; Andrew M. Atz; Steven D. Colan; L. Lu Ann Minich; Christian Pizarro; Kirk R. Kanter; James Jaggers; Jeffrey P. Jacobs; Catherine D. Krawczeski; Nancy A. Pike; Brian W. McCrindle; Lisa Virzi; J. William Gaynor

BACKGROUND The Norwood procedure with a modified Blalock-Taussig (MBT) shunt, the first palliative stage for single-ventricle lesions with systemic outflow obstruction, is associated with high mortality. The right ventricle-pulmonary artery (RVPA) shunt may improve coronary flow but requires a ventriculotomy. We compared the two shunts in infants with hypoplastic heart syndrome or related anomalies. METHODS Infants undergoing the Norwood procedure were randomly assigned to the MBT shunt (275 infants) or the RVPA shunt (274 infants) at 15 North American centers. The primary outcome was death or cardiac transplantation 12 months after randomization. Secondary outcomes included unintended cardiovascular interventions and right ventricular size and function at 14 months and transplantation-free survival until the last subject reached 14 months of age. RESULTS Transplantation-free survival 12 months after randomization was higher with the RVPA shunt than with the MBT shunt (74% vs. 64%, P=0.01). However, the RVPA shunt group had more unintended interventions (P=0.003) and complications (P=0.002). Right ventricular size and function at the age of 14 months and the rate of nonfatal serious adverse events at the age of 12 months were similar in the two groups. Data collected over a mean (+/-SD) follow-up period of 32+/-11 months showed a nonsignificant difference in transplantation-free survival between the two groups (P=0.06). On nonproportional-hazards analysis, the size of the treatment effect differed before and after 12 months (P=0.02). CONCLUSIONS In children undergoing the Norwood procedure, transplantation-free survival at 12 months was better with the RVPA shunt than with the MBT shunt. After 12 months, available data showed no significant difference in transplantation-free survival between the two groups. (ClinicalTrials.gov number, NCT00115934.)


The Journal of Thoracic and Cardiovascular Surgery | 2009

An empirically based tool for analyzing mortality associated with congenital heart surgery

Sean M. O'Brien; David R. Clarke; Jeffrey P. Jacobs; Marshall L. Jacobs; François Lacour-Gayet; Christian Pizarro; Karl F. Welke; Bohdan Maruszewski; Zdzislaw Tobota; Weldon J. Miller; Leslie Hamilton; Eric D. Peterson; Constantine Mavroudis; Fred H. Edwards

OBJECTIVE Analysis of congenital heart surgery results requires a reliable method of estimating the risk of adverse outcomes. Two major systems in current use are based on projections of risk or complexity that were predominantly subjectively derived. Our goal was to create an objective, empirically based index that can be used to identify the statistically estimated risk of in-hospital mortality by procedure and to group procedures into risk categories. METHODS Mortality risk was estimated for 148 types of operative procedures using data from 77,294 operations entered into the European Association for Cardiothoracic Surgery (EACTS) Congenital Heart Surgery Database (33,360 operations) and the Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (43,934 patients) between 2002 and 2007. Procedure-specific mortality rate estimates were calculated using a Bayesian model that adjusted for small denominators. Each procedure was assigned a numeric score (the STS-EACTS Congenital Heart Surgery Mortality Score [2009]) ranging from 0.1 to 5.0 based on the estimated mortality rate. Procedures were also sorted by increasing risk and grouped into 5 categories (the STS-EACTS Congenital Heart Surgery Mortality Categories [2009]) that were chosen to be optimal with respect to minimizing within-category variation and maximizing between-category variation. Model performance was subsequently assessed in an independent validation sample (n = 27,700) and compared with 2 existing methods: Risk Adjustment for Congenital Heart Surgery (RACHS-1) categories and Aristotle Basis Complexity scores. RESULTS Estimated mortality rates ranged across procedure types from 0.3% (atrial septal defect repair with patch) to 29.8% (truncus plus interrupted aortic arch repair). The proposed STS-EACTS score and STS-EACTS categories demonstrated good discrimination for predicting mortality in the validation sample (C-index = 0.784 and 0.773, respectively). For procedures with more than 40 occurrences, the Pearson correlation coefficient between a procedures STS-EACTS score and its actual mortality rate in the validation sample was 0.80. In the subset of procedures for which RACHS-1 and Aristotle Basic Complexity scores are defined, discrimination was highest for the STS-EACTS score (C-index = 0.787), followed by STS-EACTS categories (C-index = 0.778), RACHS-1 categories (C-index = 0.745), and Aristotle Basic Complexity scores (C-index = 0.687). When patient covariates were added to each model, the C-index improved: STS-EACTS score (C-index = 0.816), STS-EACTS categories (C-index = 0.812), RACHS-1 categories (C-index = 0.802), and Aristotle Basic Complexity scores (C-index = 0.795). CONCLUSION The proposed risk scores and categories have a high degree of discrimination for predicting mortality and represent an improvement over existing consensus-based methods. Risk models incorporating these measures may be used to compare mortality outcomes across institutions with differing case mixes.


Circulation | 2015

2014 ACC/AHA Key Data Elements and Definitions for Cardiovascular Endpoint Events in Clinical Trials A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Data Standards (Writing Committee to Develop Cardiovascular Endpoints Data Standards)

Karen A. Hicks; James E. Tcheng; Biykem Bozkurt; Bernard R. Chaitman; Donald E. Cutlip; Andrew Farb; Gregg C. Fonarow; Jeffrey P. Jacobs; Michael R. Jaff; Judith H. Lichtman; Marian C. Limacher; Kenneth W. Mahaffey; Roxana Mehran; Steven E. Nissen; Eric E. Smith; Shari Targum

This document was approved by the American Heart Association Science A College of Cardiology Board of Trustees on November 12, 2014. The American College of Cardiology requests that this document be cited a Fonarow GC, Jacobs JP, Jaff MR, Lichtman JH, Limacher MC, Mahaffey KW elements and definitions for cardiovascular endpoint events in clinical trials: Task Force on Clinical Data Standards (Writing Committee to Develop Cardi This article has been copublished in Circulation. Copies: This document is available on the World Wide Web sites of the Association (my.americanheart.org). For copies of this document, please con [email protected]. Permissions: Multiple copies, modification, alteration, enhancement, and permission of the American College of Cardiology. Requests may be compl author-agreement/obtaining-permission). Marian C. Limacher, MD, FACC, FAHA Kenneth W. Mahaffey, MD, FACC Roxana Mehran, MD, FACC, FAHA Steven E. Nissen, MD, MACC, FAHA Eric E. Smith, MD, MPH, FAHA Shari L. Targum, MD, FACC*


The Journal of Thoracic and Cardiovascular Surgery | 2008

Cardiac surgery in infants with low birth weight is associated with increased mortality: Analysis of the Society of Thoracic Surgeons Congenital Heart Database

Christopher L. Curzon; Sarah Milford-Beland; Jennifer S. Li; Sean M. O'Brien; Jeffrey P. Jacobs; Marshall L. Jacobs; Karl F. Welke; Andrew J. Lodge; Eric D. Peterson; James Jaggers

OBJECTIVE The evaluation of operative mortality risk for cardiac surgery in infants with low weight is limited. To determine whether low weight is a risk factor for increased mortality, we reviewed the experience within the Society of Thoracic Surgeons Congenital Heart Surgery Database of infants who have undergone surgical correction or palliation for congenital heart disease. METHODS We analyzed mortality in 3022 infants ages 0 to 90 days weighing 1 to 2.5 kg (n = 517) and greater than 2.5 to 4 kg (n = 2505) who underwent cardiac surgery from 2002 through 2004 at 32 participating centers. Patients were grouped according to the primary procedure performed and analyzed according to their weight at the time of surgical intervention. Patients were also analyzed according to Risk Adjustment for Congenital Heart Surgery-1 and Aristotle Basic Complexity scores. RESULTS Compared with infants weighing 2.5 to 4 kg, infants weighing less than 2.5 kg had a significantly higher mortality for the following operations: repair of coarctation of the aorta, total anomalous pulmonary venous connection repair, arterial switch procedure, systemic to pulmonary artery shunt, and the Norwood procedure. Lower infant weight remained strongly associated with mortality risk after stratifying the population by Risk Adjustment for Congenital Heart Surgery-1 levels 2 through 6 and Aristotle Basic Complexity levels 2 through 4. CONCLUSIONS Low weight at the time of surgical intervention is associated with increased mortality in patients undergoing several types of cardiovascular procedures. These data do not allow assessment of specific risks or benefits of any particular treatment strategy. However, they do support the need for prospective analysis of specific treatment strategies for these high-risk patients.


Critical Care Medicine | 2000

Outcome of cardiopulmonary resuscitation in a pediatric cardiac intensive care unit.

David Parra; Bala R Totapally; Evan M. Zahn; Jeffrey P. Jacobs; Abdul Aldousany; Redmond P. Burke; Anthony C. Chang

ObjectiveTo determine the eventual outcome of children with heart disease who had cardiopulmonary resuscitation (CPR) in a specialized pediatric cardiac intensive care unit (CICU), and to define the influence of any prearrest variables on the outcome. DesignA retrospective review of patients’ medical records. SettingA pediatric CICU of a tertiary pediatric teaching hospital. Patients and MethodsPatients were all children who presented with cardiopulmonary arrest and who were administered CPR in the pediatric CICU between June 1995 and June 1997. Prearrest variables such as age, diagnosis, prior cardiac surgery, and inotropic support with epinephrine, as well as cause of arrest, were evaluated. Measurements and Main ResultsThirty-two patients, ranging in age from 1 day to 21 yrs (median, 1 month), satisfied criteria for inclusion in the study group. These 32 patients had a total of 38 episodes of cardiopulmonary arrest. Twenty-five of these patients (78%) had cardiac surgery before arrest. Inotropic support with continuous infusion of epinephrine was being administered at the time of arrest in 18 of 38 (47%) arrests. These prearrest variables did not influence outcome of CPR.Of the 38 episodes of CPR, 24 episodes (63%) were successful, with 20 episodes resulting in return of spontaneous circulation and four patients being successfully placed on mechanical cardiopulmonary support. Fourteen children, including all four patients who were rescued with mechanical cardiopulmonary support, survived to discharge. At 6-month follow-up, 11 patients were still alive, with three having neurologic impairment. ConclusionsAfter cardiopulmonary resuscitation in this pediatric CICU, the rate of success was 63% and the rate of survival was 42%. Prior cardiac surgery and use of epinephrine before arrest did not influence the outcome of CPR. The availability of effective mechanical cardiopulmonary support can improve the outcome of CPR.


Circulation | 2012

Predictors of long-term survival after coronary artery bypass grafting surgery: results from the Society of Thoracic Surgeons Adult Cardiac Surgery Database (the ASCERT study).

David M. Shahian; Sean M. O'Brien; Shubin Sheng; Frederick L. Grover; John E. Mayer; Jeffrey P. Jacobs; Jocelyn M. Weiss; Elizabeth R. DeLong; Eric D. Peterson; William S. Weintraub; Maria V. Grau-Sepulveda; Lloyd W. Klein; Richard E. Shaw; Kirk N. Garratt; Issam Moussa; Cynthia M. Shewan; George Dangas; Fred H. Edwards

Background— Most survival prediction models for coronary artery bypass grafting surgery are limited to in-hospital or 30-day end points. We estimate a long-term survival model using data from the Society of Thoracic Surgeons Adult Cardiac Surgery Database and Centers for Medicare and Medicaid Services. Methods and Results— The final study cohort included 348 341 isolated coronary artery bypass grafting patients aged ≥65 years, discharged between January 1, 2002, and December 31, 2007, from 917 Society of Thoracic Surgeons–participating hospitals, randomly divided into training (n=174 506) and validation (n=173 835) samples. Through linkage with Centers for Medicare and Medicaid Services claims data, we ascertained vital status from date of surgery through December 31, 2008 (1- to 6-year follow-up). Because the proportional hazards assumption was violated, we fit 4 Cox regression models conditional on being alive at the beginning of the following intervals: 0 to 30 days, 31 to 180 days, 181 days to 2 years, and >2 years. Kaplan-Meier–estimated mortality was 3.2% at 30 days, 6.4% at 180 days, 8.1% at 1 year, and 23.3% at 3 years of follow-up. Harrells C statistic for predicting overall survival time was 0.732. Some risk factors (eg, emergency status, shock, reoperation) were strong predictors of short-term outcome but, for early survivors, became nonsignificant within 2 years. The adverse impact of some other risk factors (eg, dialysis-dependent renal failure, insulin-dependent diabetes mellitus) continued to increase. Conclusions— Using clinical registry data and longitudinal claims data, we developed a long-term survival prediction model for isolated coronary artery bypass grafting. This provides valuable information for shared decision making, comparative effectiveness research, quality improvement, and provider profiling.Background— Most survival prediction models for coronary artery bypass grafting surgery are limited to in-hospital or 30-day end points. We estimate a long-term survival model using data from the Society of Thoracic Surgeons Adult Cardiac Surgery Database and Centers for Medicare and Medicaid Services. Methods and Results— The final study cohort included 348 341 isolated coronary artery bypass grafting patients aged ≥65 years, discharged between January 1, 2002, and December 31, 2007, from 917 Society of Thoracic Surgeons–participating hospitals, randomly divided into training (n=174 506) and validation (n=173 835) samples. Through linkage with Centers for Medicare and Medicaid Services claims data, we ascertained vital status from date of surgery through December 31, 2008 (1- to 6-year follow-up). Because the proportional hazards assumption was violated, we fit 4 Cox regression models conditional on being alive at the beginning of the following intervals: 0 to 30 days, 31 to 180 days, 181 days to 2 years, and >2 years. Kaplan-Meier–estimated mortality was 3.2% at 30 days, 6.4% at 180 days, 8.1% at 1 year, and 23.3% at 3 years of follow-up. Harrells C statistic for predicting overall survival time was 0.732. Some risk factors (eg, emergency status, shock, reoperation) were strong predictors of short-term outcome but, for early survivors, became nonsignificant within 2 years. The adverse impact of some other risk factors (eg, dialysis-dependent renal failure, insulin-dependent diabetes mellitus) continued to increase. Conclusions— Using clinical registry data and longitudinal claims data, we developed a long-term survival prediction model for isolated coronary artery bypass grafting. This provides valuable information for shared decision making, comparative effectiveness research, quality improvement, and provider profiling. # CLINICAL PERSPECTIVE {#article-title-39}


The Annals of Thoracic Surgery | 2010

Contemporary Patterns of Management of Tetralogy of Fallot: Data From The Society of Thoracic Surgeons Database

Hamad F. Al Habib; Jeffrey P. Jacobs; Constantine Mavroudis; Christo I. Tchervenkov; Sean M. O'Brien; Siamak Mohammadi; Marshall L. Jacobs

BACKGROUND The Society of Thoracic Surgeons Database was queried to ascertain current trends in management of tetralogy of Fallot (TOF) and to determine the prevalence of various surgical techniques. METHODS The study population (n = 3059 operations) was all index operations in 2002-2007, age 0-18 years with Primary Diagnosis of TOF, and Primary Procedure TOF repair or palliation. Patients with Pulmonary Atresia, Absent Pulmonary Valve, and Atrioventricular Canal were excluded. RESULTS 294 patients had initial palliation, including 178 neonates. 2534 patients had repair of TOF as the initial operation (primary repair), including 154 neonates. 217 patients had repair of TOF after prior palliation. Of patients who had primary repair (n = 2534), 975 had repair at 3 to 6 months, 614 at 6 months to 1 year, 492 at 1 to 3 months, and 154 at 0 to 30 days. Of patients who had repair following prior palliation (n = 217), 65 had repair in the first 6 months of life, 111 at 6 months to 1 year, and only 41 (18.9%) at more than 1 year of age. Type of repair: Of 2534 primary repairs, 581 (23%) had no ventriculotomy, 571 (23%) had nontransanular patch, 1329 (52%) had transanular patch, and 53 (2%) had right ventricle to pulmonary artery conduits. Of repairs after prior palliation (n = 217), 20 (9%) had no ventriculotomy, 30 (14%) had nontransanular patch, 144 (66%) had transanular patch, and 24 (11%) had conduits. Discharge mortality (95% confidence interval; CI) was 22 of 294 (7.5%; CI: 4.7%-11.1%) for initial palliation, 33 of 2534 (1.3%; CI: 0.9%-1.8%) for primary repair, and 2 of 217 (0.9%; CI: 0.1%-3.3%) for secondary repair. For neonates, discharge mortality was 11 of 178 (6.2%; CI: 3.1%-10.8%) for palliation and 12 of 154 (7.8%; CI: 4.1%-13.2%) for primary repair. CONCLUSIONS Primary repair in the first year of life is the most prevalent strategy. Despite contemporary awareness of the late consequences of pulmonary insufficiency, ventriculotomy with transanular patch remains the most prevalent technique, both for primary repair and for repair following palliation.


The Annals of Thoracic Surgery | 2010

Successful linking of the Society of Thoracic Surgeons adult cardiac surgery database to Centers for Medicare and Medicaid Services Medicare data.

Jeffrey P. Jacobs; Fred H. Edwards; David M. Shahian; Constance K. Haan; John D. Puskas; David L.S. Morales; James S. Gammie; Juan A. Sanchez; J. Matthew Brennan; Sean M. O'Brien; Rachel S. Dokholyan; Bradley G. Hammill; Lesley H. Curtis; Eric D. Peterson; Vinay Badhwar; Kristopher M. George; John E. Mayer; W. Randolph Chitwood; Gordon F. Murray; Frederick L. Grover

BACKGROUND The Centers for Medicare and Medicaid Services (CMS) Medicare database complements The Society of Thoracic Surgeons (STS) database by providing information about long-term outcomes and cost. This study demonstrates the feasibility of linking STS data to CMS data and examines the penetration, completeness, and representativeness of the STS database. METHODS Using variables common to both STS and CMS databases, STS operations were linked to CMS data for all CMS coronary artery bypass graft surgery (CABG) hospitalizations discharged between 2000 and 2007, inclusive. For each CMS CABG hospitalization, it was determined whether a matching STS record existed. RESULTS Center-level penetration (number of CMS sites with at least one matched STS participant divided by the total number of CMS CABG sites) increased from 45% to 78%. In 2007, 854 of 1,101 CMS CABG sites (78%) were linked to an STS site. Patient-level penetration (number of CMS CABG hospitalizations done at STS sites divided by the total number of CMS CABG hospitalizations) increased from 51% to 84%. In 2007, 94,409 of 111,967 CMS CABG hospitalizations (84%) were at an STS site. Completeness of case inclusion at STS sites (number of CMS CABG cases at STS sites linked to STS records divided by the total number of CMS CABG cases at STS sites) increased from 88% to 97%. In 2007, 88,857 of 91,363 CMS CABG hospitalizations at STS sites (97%) were linked to an STS record. CONCLUSIONS The successful linking of STS and CMS databases demonstrates high and increasing penetration and completeness of the STS database. Linking STS and CMS data will facilitate studying long-term outcomes of cardiothoracic surgery.


Pediatrics | 2015

Neurodevelopmental Outcomes After Cardiac Surgery in Infancy

J. William Gaynor; Christian Stopp; David Wypij; Dean B. Andropoulos; Joseph Atallah; Andrew M. Atz; John Beca; Mary T. Donofrio; Kim Duncan; Nancy S. Ghanayem; Caren S. Goldberg; Hedwig H. Hövels-Gürich; Fukiko Ichida; Jeffrey P. Jacobs; Robert Justo; Beatrice Latal; Jennifer S. Li; William T. Mahle; Patrick S. McQuillen; Shaji C. Menon; Victoria L. Pemberton; Nancy A. Pike; Christian Pizarro; Lara S. Shekerdemian; Anne Synnes; Ismee A. Williams; David C. Bellinger; Jane W. Newburger

BACKGROUND: Neurodevelopmental disability is the most common complication for survivors of surgery for congenital heart disease (CHD). METHODS: We analyzed individual participant data from studies of children evaluated with the Bayley Scales of Infant Development, second edition, after cardiac surgery between 1996 and 2009. The primary outcome was Psychomotor Development Index (PDI), and the secondary outcome was Mental Development Index (MDI). RESULTS: Among 1770 subjects from 22 institutions, assessed at age 14.5 ± 3.7 months, PDIs and MDIs (77.6 ± 18.8 and 88.2 ± 16.7, respectively) were lower than normative means (each P < .001). Later calendar year of birth was associated with an increased proportion of high-risk infants (complexity of CHD and prevalence of genetic/extracardiac anomalies). After adjustment for center and type of CHD, later year of birth was not significantly associated with better PDI or MDI. Risk factors for lower PDI were lower birth weight, white race, and presence of a genetic/extracardiac anomaly (all P ≤ .01). After adjustment for these factors, PDIs improved over time (0.39 points/year, 95% confidence interval 0.01 to 0.78; P = .045). Risk factors for lower MDI were lower birth weight, male gender, less maternal education, and presence of a genetic/extracardiac anomaly (all P < .001). After adjustment for these factors, MDIs improved over time (0.38 points/year, 95% confidence interval 0.05 to 0.71; P = .02). CONCLUSIONS: Early neurodevelopmental outcomes for survivors of cardiac surgery in infancy have improved modestly over time, but only after adjustment for innate patient risk factors. As more high-risk CHD infants undergo cardiac surgery and survive, a growing population will require significant societal resources.


Cardiology in The Young | 2006

The nomenclature, definition and classification of hypoplastic left heart syndrome

Christo I. Tchervenkov; Jeffrey P. Jacobs; Paul M. Weinberg; Vera Demarchi Aiello; Marie J. Béland; Steven D. Colan; Martin J. Elliott; Rodney Franklin; J. William Gaynor; Otto N. Krogmann; Hiromi Kurosawa; Bohdan Maruszewski; Giovanni Stellin

The hypoplastic left heart syndrome encompasses a spectrum of cardiac malformations that are characterized by significant underdevelopment of the components of the left heart and the aorta, including the left ventricular cavity and mass. At the severe end of the spectrum is found the combination of aortic and mitral atresia, when the left ventricle can be close to non-existent. At the mild end are the patients with hypoplasia of the aortic and mitral valves, but without intrinsic valvar stenosis or atresia, and milder degrees of left ventricular hypoplasia. Although the majority of the patients are suitable only for functionally univentricular repair, a small minority may be candidates for biventricular repair. The nature of the syndrome was a topic for discussion at the second meeting of the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, the Nomenclature Working Group, held in Montreal, Canada, over the period January 17 through 19, 2003. Subsequent to these discussions, the Nomenclature Working Group was able to create a bidirectional crossmap between the nomenclature initially produced jointly on behalf of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and the alternative nomenclature developed on behalf of the Association for European Paediatric Cardiology. This process is a part of the overall efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system of nomenclature for paediatric and congenital cardiac disease, the International Paediatric and Congenital Cardiac Code. In this review, we discuss the evolution of nomenclature and surgical treatment for the spectrum of lesions making up the hypoplastic left heart syndrome and its related malformations. We also present the crossmap of the associated terms for diagnoses and procedures, as recently completed by the Nomenclature Working Group.

Collaboration


Dive into the Jeffrey P. Jacobs's collaboration.

Top Co-Authors

Avatar

Marshall L. Jacobs

Johns Hopkins University School of Medicine

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

J. William Gaynor

Children's Hospital of Philadelphia

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Christo I. Tchervenkov

University of Alabama at Birmingham

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge