National Libraries and the Semantic Web: Requirements and Applications

Semantics are an integral part of bibliographic (meta-)data including authority files. So far, however, there have been only rudimentary attempts to make those data visible on the Semantic Web. This paper presents a sketch of what (national) libraries will need to supply in order to allow for broad use of their data on the Semantic Web. The main points are persistent URIs for all entities, a set of welldefined vocabularies to describe the data, and the provision of query interfaces suitable for the Semantic Web. In the final section three current projects from the German National Library are presented, in which the semantics of bibliographic data is presented using Semantic Web techniques

Influence of the presence of different alkali cations and the amount of Fe(CN)6 vacancies on CO2 adsorption on copper hexacyanoferrates

The CO2 adsorption on various Prussian blue analogue hexacyanoferrates was evaluated by thermogravimetric analysis. Compositions of prepared phases were verified by energydispersive X-ray spectroscopy, infra-red spectroscopy and powder X-ray diffraction. The influence of different alkali cations in the cubic Fm3m structures was investigated for nominal compositions A2/3Cu[Fe(CN)6]2/3 with A = vacant, Li, Na, K, Rb, Cs. The Rb and Cs compounds show the highest CO2 adsorption per unit cell, ~3.3 molecules of CO2 at 20 \ub0C and 1 bar, while in terms of mmol/g the Na compound exhibits the highest adsorption capability, ~3.8 mmol/g at 20 \ub0C and 1 bar. The fastest adsorption/desorption is exhibited by the A-cation free compound and the Li compound. The influence of the amount of Fe(CN)6 vacancies were assessed by determining the CO2 adsorption capabilities of Cu[Fe(CN)6]1/2 (Fm3m symmetry, nominally 50% vacancies), KCu[Fe(CN)6]3/4 (Fm3m symmetry, nominally 25% vacancies), and CsCu[Fe(CN)6] (I-4m2 symmetry, nominally 0% vacancies). Higher adsorption was, as expected, shown on compounds with higher vacancy concentrations

Does right thoracotomy increase the risk of mitral valve reoperation?

ObjectiveThe study objective was to determine whether a right thoracotomy approach increases the risk of mitral valve reoperation.MethodsBetween January of 1993 and January of 2004, 2469 patients with mitral valve disease underwent 2570 reoperations (1508 replacements, 1062 repairs). The approach was median sternotomy in 2444 patients, right thoracotomy in 80 patients, and other in 46 patients. Multivariable logistic regression was used to identify factors associated with median sternotomy versus right thoracotomy, mitral valve repair versus replacement, hospital death, and stroke. Factors favoring median sternotomy (P < .03) included coronary artery bypass grafting (30% vs 2%), aortic valve replacement (39% vs 2%), tricuspid valve repair (27% vs 13%), fewer previous cardiac operations, more recent reoperation, and no prior left internal thoracic artery graft. These factors were used to construct a propensity score for risk-adjusting outcomes.ResultsHospital mortality was 6.7% (163/2444) for the median sternotomy approach and 6.3% (5/80) for the thoracotomy approach (P = .9). Risk factors (P < .04) included earlier surgery date, higher New York Heart Association class, emergency operation, multiple reoperations, and mitral valve replacement. Stroke occurred in 66 patients (2.7%) who underwent a median sternotomy and in 6 patients (7.5%) who underwent a thoracotomy (P = .006). Mitral valve replacement (vs repair) was more common in those receiving a thoracotomy (P < .04).ConclusionsCompared with median sternotomy, right thoracotomy is associated with a higher occurrence of stroke and less frequent mitral valve repair. Specific strategies for conducting the operation should be used to reduce the risk of stroke when right thoracotomy is used for mitral valve reoperation. In most instances, repeat median sternotomy, with its better exposure and greater latitude for concomitant procedures, is preferred

Off-label use of direct oral anticoagulants in patients receiving surgical mechanical and bioprosthetic heart valves

This cohort study assesses direct oral anticoagulant use in patients with surgical prosthetic heart valves in the United States and evaluates differences in preoperative and postoperative profiles in patients discharged while receiving direct oral anticoagulant vs warfarin

Results of matching valve and root repair to aortic valve and root pathology

ObjectiveFor patients with aortic root pathology and aortic valve regurgitation, aortic valve replacement is problematic because no durable bioprosthesis exists, and mechanical valves require lifetime anticoagulation. This study sought to assess outcomes of combined aortic valve and root repair, including comparison with matched bioprosthesis aortic valve replacement.MethodsFrom November 1990 to January 2005, 366 patients underwent modified David reimplantation (n = 72), root remodeling (n = 72), or valve repair with sinotubular junction tailoring (n = 222). Active follow-up was 99% complete, with a mean of 5.6 ± 4.0 years (maximum 17 years); follow-up for vital status averaged 8.5 ± 3.6 years (maximum 19 years). Propensity-adjusted models were developed for fair comparison of outcomes.ResultsThirty-day and 5-, 10-, and 15-year survivals were 98%, 86%, 74%, and 58%, respectively, similar to that of the US matched population and better than that after bioprosthesis aortic valve replacement. Propensity-score–adjusted survival was similar across procedures (P > .3). Freedom from reoperation at 30 days and 5 and 10 years was 99%, 92%, and 89%, respectively, and was similar across procedures (P > .3) after propensity-score adjustment. Patients with tricuspid aortic valves were more likely to be free of reoperation than those with bicuspid valves at 10 years (93% vs 77%, P = .002), equivalent to bioprosthesis aortic valve replacement and superior after 12 years. Bioprostheses increasingly deteriorated after 7 years, and hazard functions for reoperation crossed at 7 years.ConclusionsValve preservation (rather than replacement) and matching root procedures have excellent early and long-term results, with increasing survival benefit at 7 years and fewer reoperations by 12 years. We recommend this procedure for experienced surgical teams

A comprehensive review of the PARTNER trial

ObjectivePercutaneous transcatheter aortic valve replacement was introduced in 2002, but its effectiveness remained to be assessed.MethodsA prospective, randomized trial (the Placement of Aortic Transcatheter Valves, or PARTNER) was designed with 2 arms: PARTNER A (n = 699) for high-risk surgical patients (Society of Thoracic Surgeons score >10%, surgeon assessed risk of mortality >15%) and PARTNER B (n = 358, patients inoperable by assessment of 2 surgeons). PARTNER A patients were divided into femoral artery access transcatheter aortic valve replacement or none (n = 207), and then randomized to open aortic valve replacement (n = 351) or device (n = 348). Inclusion criteria included valve area <0.8 cm2, gradient >40 mm Hg or peak >64 mm Hg, and survival >1 year. The end point of the study was 1-year mortality.ResultsThirty-day mortality for PARTNER A was 3.4% for transcatheter aortic valve replacement and 6.5% for aortic valve replacement; 1-year mortality was 24.2% and 26.8%, respectively (P = .001 for noninferiority). The respective prevalence of stroke was 3.8% and 2.1% (P = .2), although for all neurologic events, the difference between transcatheter aortic valve replacement and aortic valve replacement was significant (P = .04), including 4.6% for femoral artery access transcatheter aortic valve replacement versus 1.4% for open aortic valve replacement (P = .05). For PARTNER B—transcatheter aortic valve replacement versus medical treatment—30-day mortality was 5.0% versus 2.8% (P = .41), and at 1 year, mortality was 30.7% versus 50.7% (P < .001), respectively. Hospitalization cost of transcatheter aortic valve replacement for PARTNER B was $78,542, or$50,200 per year of life gained. Analysis of PARTNER A strokes showed that hazard with transcatheter aortic valve replacement peaked early, but thereafter remained constant in relation to aortic valve replacement. Two-year PARTNER A data showed paravalvular regurgitation was associated with increased mortality, even when mild (P < .001). Continued access to transapical transcatheter aortic valve replacement (n = 853) showed a mortality of 8.2% and decline in strokes to 2.0%. Of the 1801 Cleveland Clinic patients reviewed to December 2010, 214 (12%) underwent transcatheter aortic valve replacement with a mortality of 1%; in 2011, 105 underwent transcatheter aortic valve replacement: 34 transapical aortic valve replacement, with no deaths, and 71 femoral artery access aortic valve replacement with 1 death.ConclusionsThe PARTNER A and B trials showed that survival has been remarkably good, but stroke and perivalvular leakage require further device development

Severe Aortic Stenosis and Coronary Artery Disease—Implications for Management in the Transcatheter Aortic Valve Replacement Era A Comprehensive Review

Management of coronary artery disease (CAD) in patients with severe aortic stenosis (AS) referred for transcatheter aortic valve replacement (TAVR) is posing challenges. Due to limited and heterogeneous data on the prevalence and clinical impact of CAD on the outcomes of TAVR and the management strategies for CAD in patients undergoing TAVR, we performed a comprehensive review of the literature. Significant CAD is present in 40% to 75% of patients undergoing TAVR. The impact of CAD on outcomes after TAVR remains understudied. Based on existing data, not all patients require revascularization before TAVR. Percutaneous coronary intervention (PCI) should be considered for severely stenotic lesions in proximal coronaries that subtend a large area of myocardium at risk. Ongoing studies randomizing patients to surgical or percutaneous management strategies for severe AS will help provide valuable data regarding the impact of CAD on TAVR outcomes, the role of PCI, and its timing in relation to TAVR