130,497 research outputs found
Repair of post-infarction left ventricular free wall rupture using an extracellular matrix patch
No full textSuccessful first-in-man Melody transcatheter valve implant in a dehisced mitral annuloplasty ring transapical valve-in-ring implant
No full textMeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Early endovascular aneurysm repair after percutaneous coronary interventions
No full textOBJECTIVE: The objective of this study was to report long-term results of early endovascular aortic aneurysm repair after percutaneous coronary intervention (PCI).
METHODS: This was a retrospective analysis of all patients presenting with abdominal aortic aneurysm and coronary artery disease treated during the same hospitalization by endovascular aortic aneurysm repair performed soon after PCI. Primary outcomes were perioperative mortality, perioperative complications, survival after treatment, and freedom from reintervention.
RESULTS: A total of 20 patients were included, and all completed both procedures. No deaths or abdominal aortic aneurysm ruptures occurred between the PCI and the aortic intervention. Perioperative mortality was 5% as one patient died of mesenteric ischemia after endovascular aneurysm repair. Major cardiovascular vascular complications occurred in four patients (20%) and included non-ST-segment elevation myocardial infarction (one) and access vessel complication (three). Mean follow-up was 94 (range, 1-164; standard deviation, 47) months. Estimated survival at 1 year, 2 years, 5 years, and 10 years was 90%, 90%, 90%, and 60%, respectively. A reoperation was required in six patients. Estimated freedom from reintervention at 1 year, 2 years, 5 years, and 10 years was 83%, 83%, 78%, and 72%, respectively.
CONCLUSIONS: Our study indicates that early endovascular aneurysm repair performed within a week after PCI may be a reasonable approach in patients with large or symptomatic aneurysms
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Investigating the Usability and Acute Effects of a Bedside Video Console to Prefrontal Cortical Activity Alterations: A Preclinical Study in Healthy Elderly
No full textElderly people at risk of developing cognitive decline; e.g., following surgery, may benefit from structured, challenging, and repetitive cognitive video training. This study assessed usability and acute effects of a newly developed bedside console (COPHYCON). Fifteen healthy elderly individuals performed a one-time 80-min intervention, including cognitive video games aimed at improving awareness and selective attention. Perceived usefulness and perceived ease of use (Technology Acceptance Model) were assessed together with measures of the achieved game level, reaction times, (in-) correct responses during ALERT and SELECT game play. Further, prefrontal cortical involvement of the regional cerebral hemoglobin saturation (rS02%) assessed with functional near infrared spectroscopy (fNIRS) (n = 5) and EEG power (n = 10) was analyzed. All participants completed the study without any adverse events. Perceived usefulness and perceived ease of use (TAM scores range 1-7) of the system varied between 3.9 and 6.3. The game levels reached for awareness varied between 9 and 11 (initial score 8-10), for reaction speed between 439 and 469 ms, and for correct responses between 74.1 and 78.8%. The highest level for the selective attention games was 2 (initial score 1), where reaction speed varied between 439 and 469ms, correct responses between 96.2 and 98.5%, respectively. The decrease of rS02% in the right prefrontal cortex during gameplay was significantly (p < 0.001) lower, compared to the left prefrontal cortex. Four participants yielded significant lower rS02% measures after exergaming with the ALERT games (p < 0.000), but not with the SELECT games. EEG recordings of theta power significantly decreased in the averaged similar to 0.25-0.75 time interval for the left prefrontal cortex sensor across the cognitive game levels between the ALERT 1 and SELECT 1, as well as between SELECT 1 and 2 games. Participants rated the usability of the COPHYCON training positively. Further results indicate that video gaming may be an effective measure to affect prefrontal cortical functioning in elderly. The results warrant a clinical explorative study investigating the feasibility of the COPHYCON in a clinical setting
Chimney and periscope grafts observed over 2 years after their use to revascularize 169 renovisceral branches in 77 patients with complex aortic aneurysms
No full textPURPOSE: To evaluate the performance of periscope and/or chimney grafts (CPGs) in the endovascular treatment of pararenal or thoracoabdominal aneurysms using off-the-shelf devices.
METHODS: Between February 2002 and August 2012, 77 consecutive patients (62 men; mean age 73±9 years) suffering from pararenal aortic (n=55), thoracoabdominal (n=16), or arch to visceral artery aneurysms (n=6) were treated with aortic stent-graft implantation requiring chimney and/or periscope grafts to maintain side branch perfusion. CPGs were planned in advance and were not used as bailout. A standardized follow-up protocol including computed tomographic angiography, laboratory testing, and clinical examination was performed at 6 weeks; 3, 6, and 12 months; and annually thereafter.
RESULTS: Technical success was achieved in 76 (99%) patients; 1 branch stent-graft became dislocated from a renal artery, which could not be re-accessed. Overall, 169 target vessels (121 renal arteries, 30 superior mesenteric arteries, 17 celiac trunks, and 1 inferior mesenteric artery) were addressed with the chimney graft configuration in 111 and the periscope graft configuration in 58. In total, 228 devices were used for the CPGs: 213 Viabahn stent-grafts and 15 bare metal stents. Over a mean 25±16 months (range 1-121), 9 patients died of unrelated causes. Nearly all (95%) of the patients demonstrated a decreased or stable aneurysm size on imaging; there was a mean 13% shrinkage in aneurysm diameter. Twenty patients had primary type I/III endoleaks at discharge; in follow-up, only 3 of these were still present (no secondary or recurrent endoleaks were noted). Additional endovascular maneuvers were required for CPG-related complications in 13 patients from intervention throughout follow-up. Overall, 4 CPGs occluded (98% target vessel patency); no stent-graft migration was observed. Renal function remained stable in all patients.
CONCLUSION: In this series, the use of CPGs has proven to be a feasible, safe, and effective way to treat thoracoabdominal and pararenal aneurysms with maintenance of blood flow to the renovisceral arteries. Nearly all of the aneurysms showed no increase in diameter over a >2-year mean follow-up, which supports the midterm adequacy of the CPG technique as a method to effectively revascularize branch vessels with few endoleaks or branch occlusions
- …
