The pyroantimonate pigments Naples yellow and lead tin antimonate yellow are recognized as some of the most stable synthetic yellow pigments in the history of art. However, this exceptional ...lightfastness is in contrast with experimental evidence suggesting that this class of mixed oxides is of semiconducting nature. In this study the electronic structure and light-induced behavior of the lead pyroantimonate pigments were determined by means of a combined multifaceted analytical and computational approach (photoelectrochemical measurements, UV–vis diffuse reflectance spectroscopy, STEM-EDS, STEM-HAADF, and density functional theory calculations). The results demonstrate both the semiconducting nature and the lightfastness of these pigments. Poor optical absorption and minority carrier mobility are the main properties responsible for the observed stability. In addition, novel fundamental insights into the role played by Na atoms in the stabilization of the otherwise intrinsically unstable Pb2Sb2O7 pyrochlore were obtained.
Cardiac surgery waitlist recommendations, which were developed based on expert opinion, poorly predict preoperative mortality. Studies reporting risk factors for waitlist mortality have not evaluated ...the risks including nonadherence to waitlist benchmarks.
In patients who underwent cardiac surgery or died on the waitlist between 2005 and 2015, we used a Fine and Gray competing risk model to identify independent predictors of waitlist mortality in 12,106 patients scheduled for urgent, semiurgent, or nonurgent surgery. The predictive variables were compared with Canadian Cardiovascular Society (CCS) waitlist recommendations using the Akaike information criterion.
A total of 101 (0.8%) patients died awaiting surgery. The median wait times and frequency waitlist deaths among emergent, urgent, semi-urgent, and nonurgent surgery were 0.6, 7.4, 69.0, 55.5 days (P < 0.001) and 6.3%, 0.8%, 0.3%, 0.6% (P < 0.001), respectively. Adherence to CCS waitlist recommendations was higher in patients who died on the waitlist (51.6% vs 70.8%, P = 0.001) and was not predictive of waitlist mortality (hazard ratio 1.48, 95% confidence interval 0.62-0.56). Independent predictors of waitlist mortality were age, aortic surgery, ejection fraction < 35%, urgent surgery, prior myocardial infarction, haemodynamic instability during cardiac catheterization, hypertension, and dyslipidemia. These variables were superior to current CCS guidelines (Akaike information criterion 1251 vs 1317, likelihood ratio test P < 0.001).
CCS waitlist recommendations were poorly predictive of waitlist mortality and the majority of waitlist deaths occur within recommended benchmarks. We identified variables associated with waitlist mortality with improved clinical performance. Our findings suggest a need to re-evaluate cardiac surgical triage criteria using evidence-based data.
Les recommandations en matière de listes d’attente en chirurgie cardiaque, qui sont fondées sur l’opinion d’experts, ne permettent pas de bien prédire la mortalité préopératoire. Les études qui rapportent des facteurs de risque de mortalité durant l’attente n’ont pas permis d’évaluer les risques, y compris le non-respect des délais de référence de la liste d’attente.
Chez les patients qui ont subi une intervention chirurgicale au cœur ou qui sont morts durant l’attente entre 2005 et 2015, nous avons utilisé le modèle de risque concurrent Fine et Gray pour déterminer les prédicteurs indépendants de mortalité durant l’attente de 12 106 patients inscrits pour une intervention chirurgicale urgente, semi-urgente ou non urgente. Nous avons comparé les variables de prédiction aux recommandations en matière de listes d’attente de la Société canadienne de cardiologie (SCC) à l’aide du critère d’information d’Akaike.
Un total de 101 (0,8 %) patients sont morts durant l’attente d’une intervention chirurgicale. Les temps d’attente médians et la fréquence des décès durant l’attente pour les interventions chirurgicales émergentes, urgentes, semi-urgentes et non urgentes étaient respectivement de 0,6, de 7,4, de 69,0 et de 55,5 jours (P < 0,001), et de 6,3 %, de 0,8 %, de 0,3 % et de 0,6 % (P < 0,001). Le respect des recommandations en matière de listes d’attente de la SCC était plus élevé chez les patients qui sont morts durant l’attente (51,6 % vs 70,8 %, P = 0,001) et n’ont pas permis de prédire la mortalité durant l’attente (rapport de risque 1,48, intervalle de confiance à 95 % 0,62-0,56). Les prédicteurs indépendants de mortalité durant l’attente étaient l’âge, la chirurgie aortique, la fraction d’éjection < 35 %, l’intervention chirurgicale urgente, l’infarctus du myocarde antérieur, l’instabilité hémodynamique durant le cathétérisme cardiaque, l’hypertension et la dyslipidémie. Ces variables étaient supérieures aux lignes directrices actuelles de la SCC (critère d’information d’Akaike 1251 vs 1317, test du rapport de vraisemblance P < 0,001).
Les recommandations en matière de listes d’attente de la SCC n’ont pas permis de bien prédire la mortalité durant l’attente et la majorité des décès durant l’attente sont survenus dans les délais de référence recommandés. Nous avons déterminé les variables associées à la mortalité durant l’attente avec une meilleure performance clinique. Nos résultats laissent croire qu’il y a lieu de réévaluer les critères de triage en chirurgie cardiaque à l’aide des données probantes.
Background Reoperative mitral valve (MV) surgery through sternotomy can be technically challenging. Limited exposure and injury to the right ventricle or patent grafts (previous coronary artery ...bypass graft surgery CABG) are potential complications upon sternal reentry. The purpose of this study was to examine the results of port access MV surgery through right minithoracotomy in patients with previous cardiac surgery performed through median sternotomy. Methods From 1998 through July 2007, 651 port access MV procedures were performed. In 107 patients (16.4%), previous cardiac surgery had been performed through midline sternotomy. Mean age was 67.5 ± 11.2 years, and 60.7% (n = 65) were male. Previous surgery included CABG (n = 45, 42.1%), aortic valve replacement (n = 9, 8.4%), aortic valve replacement/MV repair (n = 2, 1.9%), MV repair (n = 21, 19.6%), MV replacement (n = 5, 4.7%), CABG/MV replacement (n = 1, 0.9%), CABG/MV repair (n = 8, 7.5%), CABG/aortic valve replacement (n = 2, 1.9%), and others (n = 14, 13.1%). New York Heart Association functional classes were I (n = 2, 1.9%), II (n = 28, 26.2%), III (n = 50, 46.7%), and IV (n = 27, 25.2%). The endoaortic balloon was used in 75 patients (70.1%) and the Chitwood clamp in 11 patients (10.2%). In the remaining patients (n = 21, 19.6%), fibrillatory arrest was employed. Results Mitral valve repair and MV replacement were performed in 60 patients (56.1%) and 47 patients (43.9%), respectively. The 30-day mortality was 4.7% (n = 5). The mean cardiopulmonary bypass and aortic cross-clamp times were 140.8 ± 43.7 minutes and 77.0 ± 49.7 minutes, respectively. Complications included 6 reoperations for bleeding (5.6%), 1 stroke (0.9%), and 2 wound infections (1.9%). Conversion to sternotomy was required in 1 patient (0.9%) because of an acute type A dissection secondary to aortic occlusion with Chitwood clamp. The mean hospital stay was 9.6 days. During follow-up, reoperation for failure of MV repair was performed in 4 patients (3.7%). Conclusions Reoperative port access MV surgery can be performed with minimal morbidity and mortality. This approach may be the preferred technique for patients who require MV procedures after previous cardiac surgery performed through median sternotomy.
Background and aims
When children hear a novel word, they tend to associate it with a novel rather than a familiar object. The ability to map a novel word to its corresponding referent is thought to ...depend, at least in part, on language-learning strategies, such as mutual exclusivity and lexical contrast. Although the importance of word learning strategies has been broadly investigated in typically developing children as well as younger children with autism spectrum disorder, who are usually language delayed, there is a paucity of research on such strategies and their role in language learning in school-age children and adolescents with autism spectrum disorder who have failed to develop fluent speech. In this study, we examined the ability of minimally verbal children and adolescents with autism spectrum disorder to learn and retain novel words in an experimental task, as well as the cognitive, language, and social correlates of these abilities. We were primarily interested in the characteristics that differentiated between three subgroups of participants: those unable to use word learning strategies, particularly mutual exclusivity, to learn novel words; those able to learn novel words over several exposure trials but not able retain them; and those able to retain the words they learned.
Methods
Participants were 29 minimally verbal individuals with autism spectrum disorder from 5 to 17 years of age. Participants completed a computerized touchscreen novel-word-learning procedure followed by assessments of immediate retention and of delayed retention, two hours later. Participants were grouped according to whether they passed/failed at least 7 of 8 (binomial p < .035) novel word learning trials and 7 of 8 immediate or delayed retention trials, and were compared on measures of nonverbal IQ, receptive and expressive vocabulary, phonological processing, joint attention and symptom severity.
Results
Of 29 participants, 14 failed both learning and immediate retention, 8 passed learning but failed immediate retention, and 7 passed both learning and immediate retention. Group performance was highly similar for delayed retention. Language level, particularly expressive vocabulary, differentiated between participants who did and did not succeed in retention, even while controlling for differences in nonverbal IQ.
Conclusions
The ability of minimally verbal school-age children and adolescents with autism spectrum disorder to identify the referents of novel words was associated with nonverbal cognitive abilities. Retention of words was associated with concurrent expressive language abilities.
Implications
Our findings of associations between the retention of novel words acquired in a lab-based experimental task and concurrent language ability warrants further investigation with larger samples and longitudinal research designs, which may support the incorporation of contrastive word learning strategies into language learning interventions for severely language-impaired individuals with autism spectrum disorder.
Decellularization reduces the immune response to aortic valve allografts in the rat Meyer, Steven R.; Nagendran, Jeevan; Desai, Leena S. ...
Journal of thoracic and cardiovascular surgery/The Journal of thoracic and cardiovascular surgery/The journal of thoracic and cardiovascular surgery,
08/2005, Letnik:
130, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Cryopreserved valve allografts used in congenital cardiac surgery are associated with a significant cellular and humoral immune response. This might be reduced by removal of antigenic cellular ...elements (decellularization). The aim of this study was to determine the immunologic effect of decellularization in a rat allograft valve model.
Brown Norway and Lewis rat aortic valves were decellularized with a series of hypotonic and hypertonic buffers, protease inhibitors, gentle detergents (Triton X-100), and phosphate-buffered saline. Valves were implanted into Lewis rats in syngeneic and allogeneic combinations. Cellular (CD3 and CD8) infiltrates were assessed with morphometric analysis, and the humoral response was assessed with flow cytometry.
Morphometric analysis identified a significant reduction in CD3
+ cell infiltrates (cells per square millimeter of leaflet tissue) in decellularized allografts compared with that seen in nondecellularized allografts at 1 (79 ± 29 vs 3310 ± 223,
P < .001), 2 (26 ± 11 vs 109 ± 20,
P = .004), and 4 weeks (283 ± 122 vs 984 ± 145,
P < .001). Anti-CD8 staining confirmed the majority of infiltrates were cytotoxic T cells. Flow cytometric mean channel fluorescence intensity identified a negative shift (abrogated antibody formation) for decellularized allografts compared with nondecellularized allografts at 2 (19 ± 1 vs 27 ± 3,
P = .033), 4 (35 ± 2 vs 133 ± 29,
P = .001), and 16 weeks (28 ± 2 vs 166 ± 54,
P = .017).
Decellularization significantly reduces the cellular and humoral immune response to allograft tissue. This could prolong the durability of valve allografts and might prevent immunologic sensitization of allograft recipients.
Procedural outcomes for transcatheter aortic valve implantation (TAVI) are well described. However, limited information exists regarding patient screening and selection. Thus, the purpose of the ...study was to review consecutive patients referred for TAVI from an inclusive-defined population. The Mazankowski Alberta Heart Institute TAVI program has maintained a prospective database on all referred patients. Patients are reviewed in outpatient clinic attended by a nurse, cardiologist, cardiac surgeon, and administrative assistant. After workup is complete, a TAVI Heart Team conference occurs to accept or reject each patient. Since November 2009, 276 patients (145 men and 131 women) have been referred with a steady increase in the number of referrals annually. Mean age was 82.2 years (men 81.6 and women 82.8), with 13% aged <70 years. Mean EuroSCORE was 13.8 and mean STS score was 5.7. Of the referred patients, 34% received TAVI, 17% were rejected, 12% underwent open AVR, 10% refused TAVI, and 27% are currently being assessed or followed. There were no differences in the mean EuroSCORE (13.4 vs 14.3; p = 0.64) or STS scores (5.2 vs 6.4; p = 0.13) of those accepted for TAVI versus those who were not. In conclusion, a team-based approach to assess this complex patient population is essential to ensure efficient and comprehensive evaluation, in turn determining appropriate care allocation. With expansion of clinical experience and the evidence supporting TAVI, the Heart Teams defined to assess this patient population will be burdened with increased clinical commitment and require appropriate support.
Polymeric materials have been used by painting conservator-restorers as consolidants and/or varnishes for wall paintings. The application of these materials is carried out when confronting loose ...paint layers or as a protective coating. However, these materials deteriorate and cause physiochemical alterations to the treated surface. In the past, the monumental neo-gothic wall painting ‘The Last Judgment’ in the chapel of Sint-Jan Berchmanscollege in Antwerp, Belgium was treated with a synthetic polymeric material. This varnish deteriorated significantly and turned brown, obscuring the paint layers. Given also that the varnish was applied to some parts of the wall painting and did not cover the entire surface, it was necessary to remove it in order to restore the original appearance of the wall painting. Previous attempts carried out by conservator-restorers made use of traditional cleaning methods, which led to damage of the fragile paint layers. Therefore, gel cleaning was proposed as a less invasive and more controllable method for gently softening and removing the varnish. The work started by identifying the paint stratigraphy and the deteriorated varnish via optical microscopy (OM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. A polyvinyl alcohol–borax/agarose (PVA–B/AG) hydrogel loaded with a number of solvents/solvent mixtures was employed in a series of tests to select the most suitable hydrogel composite. By means of the hydrogel composite loaded with 10% propylene carbonate, it was possible to safely remove the brown varnish layer. The results were verified by visual examinations (under visible light ‘VIS’ and ultraviolet light ‘UV’) as well as OM and FTIR spectroscopy.
Objective Cryopreserved allograft tissue used in the Norwood procedure for infants with hypoplastic left heart syndrome causes a marked immunologic sensitization that may complicate future heart ...transplantation. Treatment of the allograft tissue before implantation may prevent this sensitization. The purpose of this study was to assess the anti-human leukocyte antigen antibody response to glutaraldehyde-treated allograft tissue used in the repair of hypoplastic left heart syndrome. Methods Since June 2005, the University of Alberta has subjected allograft vascular tissue used in the Norwood procedure to glutaraldehyde treatment. An observational study was designed to assess whether glutaraldehyde treatment of the allograft tissue affected subsequent panel reactive antibody after patch implantation. Panel reactive antibodies for class I (human leukocyte antigen-A, B, C) and class II (human leukocyte antigen-DR, DQ) antibodies were measured 4 months postoperatively using flow cytometry. Results Fourteen patients underwent a Norwood procedure using glutaraldehyde-treated allograft tissue. Historical controls consisted of 12 patients who underwent a Norwood procedure using untreated allograft tissue. At 4 months, infants who had received glutaraldehyde-treated allograft tissue had lower class I panel reactive antibody (7.3% ± 17.4% median, 0% vs 61.9% median, 73% ± 39.9%; P = .0005) and class II panel reactive antibody (6.1% median, 0% ± 22.7% vs 49.3% median, 63% ± 41.9%, P = .001) compared with the historical controls. Conclusion Intraoperative glutaraldehyde treatment of allograft tissue used in hypoplastic left heart syndrome repair prevents the profound immunologic sensitization that occurs in the majority of infants undergoing surgical palliation. In patients requiring subsequent heart transplantation, this decreases the risk of antibody-mediated rejection and increases the likelihood of finding a suitable donor, thus improving access to transplantation.
With increasing frequency, so-called "patent trolls," patent owners that do not manufacture products embodying its patent (i.e., non-practicing entities or NPEs), are pursuing patent infringement ...before the United States International Trade Commission. Currently, the only impediment to a NPE to do so is the ITC's statutory domestic industry requirement under 19 U.S.C. § 1337(a)(3)(A)-(C). Currently, a successful NPE, which has already licensed its asserted patent, may be able to satisfy the domestic industry requirement through its licensee's domestic activities related to an embodying product or by its own domestic licensing activity. In order to protect American industry from the costs of NPE infringement suits before the ITC, Congress would need to amend § 1337(a)(3)(A)-(C) to add an explicit "manufacturing in the United States" requirement.
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