bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decellularized In-Vitro Tissue-Engineered Heart Valves - First In-Vivo Results
Authors: Driessen-Mol Anita , Dijkman Petra E. , Frese Laura , Emmert Maximilian Y. , Grunenfelder Juerg , Sidler Michele , Weber Benedikt , Sanders Bart , Jenni Rolf , Baaijens Frank P.T. , Simon P. Hoerstrup Simon P. Hoerstrup 
Published: July 2012

AbstractDecellularized xenogeneic and allogeneic heart valves are used as matrices for tissue regeneration. However, xenografts are associated with a risk of immunogenic reactions or disease transmission and homografts are sparse. Further, remodeling capacity of these matrices is questioned, as cell infiltration is limited. Alternatively, biodegradable synthetic materials are attractive as of their unlimited supply and freedom in valve geometry, with sufficient capacity for cell infiltration and neotissue formation and remodeling, but with cell-mediated leaflet retraction and thickening as common problem with in-vivo application. To overcome cell-mediated leaflet retraction and thickening and the limitations when using xenografts or homografts, we propose to decellularize in-vitro cultured tissue-engineered heart valves as off-the-shelf matrices for in-vivo regeneration. Tissue-engineered heart valves are grown based on ovine vascular cells seeded onto PGA/P4HB valvular shaped scaffolds and exposed to dynamic loading in bioreactors for 4 weeks. Decellularization of in-vitro cultured tissue-engineered heart valves is demonstrated feasible with efficient cell removal and preservation of the collagen architecture and tissue strength. Storage of these valves up to 18 months did not affect tissue properties. Decellularization strongly reduced leaflet retraction and, therewith, improved valvular function up to 24 hours in a valve tester. In-vivo performance of decellularized in-vitro cultured tissue-engineered heart valves after trans-apical implantation in pulmonary position in sheep was evaluated after 8 (n=1), 16 (n=1) and 24 (n=1) weeks. Complete cellular repopulation was demonstrated within 8 weeks with excellent in-vivo performance and no signs of tissue thickening. Moderate regurgitation developed after 16 weeks with leaflet prolapse after 24 weeks and a reduced leaflet area, likely due to minimal coaptation in the current valve design. Minimal coaptation makes the leaflets prone to prolapse with direct loss of coaptation when repopulating cells exert traction forces. Mechanical analyses demonstrated tissue remodeling with a trend towards the development of anisotropic tissue properties in time, demonstrating the promising nature of decellularized in-vitro cultured tissue-engineered heart valves for in-vivo regeneration. Efforts are ongoing to increase the number of samples and to optimize valve design and geometry to increase leaflet coaptation and maintain optimal valve performance.
The European Union's Seventh Framework Program is acknowledged for funding this study
Atypical expression and regulation of smooth muscle markers in human calcified valves
Authors: Latif Najma , Sarathchandra Padmini , Yacoub Magdi H. , Chester Adrian H. 
Published: July 2012

AbstractCalcific aortic stenosis and atherosclerosis share many similar characteristics suggesting that similar mediators and pathogenic pathways are involved. In both conditions, the native cells are quiescent. However upon damage, both valve interstitial cells (VICs) and smooth muscle cells (SMCs) in the valve and the vascular wall respectively undergo remodelling and transformation. We hypothesise that the smooth muscle cell phenotype plays a role during the calcification process. 12 normal and 16 calcified valves were analysed for smooth muscle markers including smooth muscle α-actin, smooth muscle myosin, calponin, caldesmon, desmin, SM1 and SM2 by immunocytochemistry. The expression of myocardin-related transcription factors, (MRTFA/B) as key regulators of smooth muscle gene expression, was also evaluated. Normal human valves demonstrated the expression of smooth muscle markers localised to the base of the valve. Occasionally smooth muscle markers were seen in small groups of cells in the region from the base to the central region of the valve but never in the region from the central to the co-apting edge. Smooth muscle markers in all the calcified valves demonstrated an increased and aberrant expression. The expression of smooth muscle myosin, SM1, SM2, calponin and smooth muscle α-actin was found to be abundantly expressed around calcified nodules and distal to the nodules. The pattern of staining was frequently localised along the majority of the valve tissue as well as in isolated cells. Additionally, regions of the endothelium and endothelial cells lining the vessels were found to be positive for smooth muscle markers in 9/16 calcified valves. Normal valves did not demonstrate any expression of MRTFs. However, MRTF-A and MRTF-B were induced in calcified valves in a similar pattern to the expression of smooth muscle markers. They were also induced in the endothelium and the endothelial cells lining some vessels. Importantly, the expression of MRTFs was nuclear in both VICs and endothelial cells indicative of activation. TGFβ1 (10ng/ml) was able to induce and translocate the expression of MRTF-A to the nucleus in VICs within 4 hours in some isolates.
Calcified valves harbour a greatly increased number of smooth muscle marker-positive VICs and endothelial cells. This aberrant expression in endothelial cells may emulate endothelial to mesenchymal transformation (EMT) during embyonic valvulogenesis. Concomittantly, calcified valves expressed MRTFs, key regulators of smooth muscle gene expression. The presence of smooth muscle cell markers and MRTFs in calcified valves suggest a role for this cell phenotype in the development of the calcification process.
A Completely Biological, Tissue Engineered Valve Leaflet Suitable for TAVI
Authors: McAllister Todd , Dusserre Nathalie , Chronos Nicolas , L'Heureux Nicolas 
Published: July 2012

AbstractClinically available transcatheter aortic valve replacement (TAVR) technologies typically use chemically fixed bovine or equine tissues for the valve leaflets. While these fixed, xenogeneic materials have been used with success in devices placed by open surgical access, the tissue thickness (>500 microns) adds significantly to the overall crossing profile of the delivery device. Complications associated with device diameter are generally reported in at least 10-20% of clinical cases, making a reduced crossing profile one of the most critical targets for second generation TAVR devices. Another limitation associated with pericardium is fatigue induced delamination. Previously we have reported clinical results with a completely autologous tissue engineered vascular graft built using a process termed sheet-based tissue engineering. Using this approach, we were able to build small diameter blood vessels with supraphysiologic burst pressures, and demonstrated clinical durability with time points out to 3 years. Importantly, this tissue engineering approach requires no chemical fixation or exogenous biomaterials. More recently, we reported initial human use with an allogeneic version of the vessel. With time points out to 1 year, the allogeneic tissue engineered material demonstrated no evidence of immune reaction. This transition to an off-the shelf, allogeneic approach enables use the material in a variety of new clinical indications, including valve reconstruction. Valve leaflets built from a single sheet, demonstrated ultimate tensile strength in excess of that for bovine valve leaflets. Of note, the thickness of the sheet was less than 200 microns, roughly 30 percent that of bovine pericardium. The tissue can also be compressed, further reducing the thickness to approximately 75 microns. This thin, durable, single layered tissue can be assembled onto commercially available TAVR devices resulting in a reduction in crossing profile of approximately 2 Fr. The valve leaflets can be sutured easily, coapt normally, and can withstand arterial backpressure. Given the non-laminated structure of the tissue engineered leaflet, the lack of synthetic materials, and the durability demonstrated in other clinical indications, this approach may provide not only a reduced crossing profile, but also improved long term clinical results.
A Finite Element Study of Human Pulmonary Autograft Wall Stress after the Ross Procedure
Authors: Wisneski Andrew D. , Matthews Peter B. , Azadani Ali N. , Chitsaz Sam , Lui Natalie , Guccione Julius , Ge Liang , Tseng Elaine E. 
Published: July 2012

AbstractDilatation of the pulmonary autograft after the Ross procedure can lead to aortic insufficiency and/or aneurysmal pathology requiring reoperation. Autograft remodeling occurs as the autograft wall is exposed to systemic pressure and higher wall stresses, which have not been quantified in humans. The aim of the study was to develop a realistic Finite Element (FE) model of the human pulmonary autograft and to perform simulations at systemic pressure to quantify the increases in autograft wall stress immediately after the Ross procedure. Autograft geometry was generated from high-resolution micro-computed tomography images of an explanted human pulmonary root to create a mesh of hexahedral elements. Constitutive equations were used to describe the regional tissue material properties of the human pulmonary root obtained from bi-axial stretch testing. LS-DYNA (LSTC Inc., Livermore, CA) FE software was used to simulate cardiac cycles at pulmonary and systemic pressure. Autograft dilatation and wall stress distribution were determined. Correlation of LS-DYNA model material properties to actual tissue stress-strain data was performed to ensure model accuracy. Human autograft dilation from pulmonary to systemic pressure was minimal (32.1 to 33.4mm) due to the non-linearity of the material properties. Less compliance was demonstrated at greater wall stresses. Significant increases in autograft wall stresses were found at systemic pressures. Maximal wall stresses increased approximately 10-fold in diastole (12.4 to 122.3 kPa) and 5-fold in systole (48.1 to 234.2 kPa), relative to the wall stresses at pulmonary pressures. Pulmonary autograft wall stress increased by an order of magnitude at systemic pressure. Initial autograft dilation at systemic pressure was minimal as validated by clinical studies. Chronically elevated wall stress may lead to pathologic remodeling and aneurysmal formation over time. The correspondence of this model with future studies of post-dilated autografts will lead to an improved understanding of tissue remodeling, and offer necessary data for developing improvements to the Ross procedure.
Sea Fishing at Salango (Manabí Province, Ecuador) During the Middle Formative Machalilla Phase
Authors: Béarez Philippe , Gay Patrick , Lunniss Richard 
Published: July 2012

AbstractFormative Ecuadorian coastal societies possessed the technologies and skills necessary not only for fishing, but also for deep-sea navigation. Although marine shellfish are acknowledged as significant both for dietary and religious purposes, the importance of sea-fishing is rarely highlighted or explored. In order to help evaluate more fully the significance of the sea in the Ecuadorian Formative, this paper presents recently studied evidence, excavated at the Salango site, in the Province of Manabí, for local off-shore tuna fishing during the Middle Formative Machalilla phase (ca. 1500–900 B.C.), where Scombrids constituted 80 percent of recovered fish remains. The results are then compared with those obtained from other Machalilla sites. Finally, data from the subsequent Late Formative Engoroy phase (ca. 900–100 B.C.) indicate that while Scombrid fishing continued to predominate at Salango, species capture changed through time, with a shift from yellowfin tuna in the Machalilla phase to black skipjacks in Engoroy times. It is suggested that the decline in tuna capture reflects not so much change in fishing strategy as change in the populations of fish species reaching the local marine environment.
Non‐Covalent Self‐Assembly and Covalent Polymerization Co‐Contribute to Polydopamine Formation
Authors: Hong Seonki , Na Yun Suk , Choi Sunghwan , Song In Taek , Kim Woo Youn , Lee Haeshin 
Published: July 2012

AbstractPolydopamine is the first adhesive polymer that can functionalize surfaces made of virtually all material chemistries. The material‐independent surface modification properties of polydopamine allow the functionalization of various types of medical and energy devices. However, the mechanism of dopamine polymerization has not yet been clearly demonstrated. Covalent oxidative polymerization via 5,6‐dihydroxyindole (DHI), which is similar to the mechanism for synthetic melanin synthesis, has been the clue. Here, it is reported that a physical, self‐assembled trimer of (dopamine)2/DHI exists in polydopamine, which has been known to be formed only by covalent polymerization. It is also found that the trimeric complex is tightly entrapped within polydopamine and barely escapes from the polydopamine complex. The result explains the previously reported in vitro and in vivo biocompatibility. The study reveals a different perspective of polydopamine formation, where it forms in part by the self‐assembly of dopamine and DHI, providing a new clue toward understanding the structures of catecholamines such as melanin.
Lithium‐Air Batteries: Survey on the Current Status and Perspectives Towards Automotive Applications from a Battery Industry Standpoint
Authors: Park Myounggu , Sun Heeyoung , Lee Hyungbok , Lee Junesoo , Cho Jaephil 
Published: July 2012

AbstractLi‐air rechargeable batteries theoretically have advantages from both secondary batteries and fuel cells, which can be viewed as the best technological blends for automotive applications resolving the so called mileage anxiety problem due to the limited driving range of electrical vehicles based upon Li‐ion batteries; this problem is rooted in the intrinsically small energy density of Li‐ion batteries. This very scientific trait of Li‐air batteries, which is apparently suited to the requirements of batteries for future electric vehicles, has induced quite a strong surge of research recently. This occurrence has motivated the authors to undertake a thorough review in an effort to understand the current status of Li‐air battery related technologies. A comprehensive survey from a battery industry standpoint has been conducted on the fundamentals of chemistry, utilized Li‐air cell configurations (or types) vs. performance, and major components comprising Li‐air batteries using various sources of previously published peer‐reviewed journal papers, book chapters, patents, and industrial reports. The survey results are presented here.
The effect of a booster intervention to promote hearing protection behavior in operating engineers
Authors: Hong OiSaeng , Chin Dal Lae , Fiola Lauren A. , Kazanis Anamaria S. 
Published: July 2012

AbstractBackgroundBooster interventions may be useful in promoting workers' hearing protection device (HPD) use. Previous research on the effectiveness and the optimal timeframe for boosters is limited and inconsistent.MethodsIn this randomized controlled trial, 403 workers were assigned to receive an individually tailored booster, a control booster, or no booster. The booster intervention groups were further divided by timeframe. Frequency of HPD use was measured 12 months post‐intervention.ResultsThe booster intervention groups significantly accounted for the variance in HPD use in Year 2. Workers in middle‐term booster (67–94 days) group reported a significantly greater increase in HPD use in Year 2 than those in other timeframes, when potential covariates were controlled for.ConclusionsBooster intervention letters mailed between 67 and 94 days post‐initial intervention may promote HPD use among participants. Future research should explore additional factors associated with optimal booster design, including more innovative mobile and internet‐based approaches. Am. J. Ind. Med. 56:258–266, 2013. © 2011 Wiley Periodicals, Inc.
Estimating age from adult occlusal wear: A modification of the miles method
Authors: Gilmore Cassandra C. , Grote Mark N. 
Published: July 2012

AbstractThe Miles method of age estimation relies on molar wear to estimate age and is widely used in bioarcheological contexts. However, because the method requires physical seriation and a sample of subadults to estimate wear rates it cannot be applied to many samples. Here, we modify the Miles method by scoring occlusal wear and estimating molar wear rates from adult wear gradients in 311 hunter‐gatherers and provide formulae to estimate the error associated with each age estimate. A check of the modified method in a subsample (n = 22) shows that interval estimates overlap in all but one case with age categories estimated from traditional methods; this suggests that the modifications have not hampered the ability of the Miles method to estimate age even in heterogeneous samples. As expected, the error increases with age and in populations with smaller sample sizes. These modifications allow the Miles method to be applied to skeletal samples of adult crania that were previously only amenable to cranial suture age estimation, and importantly, provide a measure of uncertainty for each age estimate. Am J Phys Anthropol 149:181–192, 2012. © Wiley Periodicals, Inc.
When Unconscious Wishes Become Laws: Policing Memory and Identity in Israel and Palestine
Authors: Cohen Shuki J. 
Published: July 2012

ABSTRACTThis paper proposes a psychoanalytically‐informed model for the policing of memory and identity in Israel and Palestine. Borrowing from both empirically‐ and clinically‐validated insights into psychopathology, it purports to account for the increasingly frequent attempts of the Israeli government to suppress alternatives to the extant Zionist narrative using legislative and administrative means. The model explains why, counter‐intuitively, these attempts to impose an idealized Zionist narrative have markedly increased in the past several years, at a time when Israel's military power, geographical expansion and economic prosperity are arguably at an all‐time high. Supported by examples from both world history and Israeli documents, the proposed model suggests a dynamic link between trauma, annihilation anxiety, hyper‐vigilance and defensive behavior on a nation‐wide level, which runs as a leitmotiv in both Israeli government actions and in sentiments expressed by a considerable portion of Israeli society, from the foundation of the state of Israel in 1948. The model further uses psychodynamic insights to account for the cognitive‐emotional rigidity underpinning the discrepancy in the perceptions of reality between Israel's narrative and its sundry worldwide alternatives. The model posits that this growing discrepancy between worldwide public opinion and Israeli internal reasoning may underlie the growing disapproval and isolation of Israel in both diplomatic circles and world media. Finally, following psychodynamically‐oriented therapeutic practices, the explanatory power of the model is harnessed to suggest potentially effective remedial attitudes and interventions, whose mutative powers may be of use to psychodynamically‐trained mental health professionals who may be involved in future reconciliation efforts between Israel and Palestine. Copyright © 2012 John Wiley & Sons, Ltd.
Applied Psychoanalysis in Biblical Interpretation
Authors: Peri Tuvia 
Published: July 2012

ABSTRACTApplied psychoanalysis is the term used to denote the practice of applying psychoanalytic theoretical concepts to a variety of social and cultural domains. This work focuses on the application of psychoanalytic concepts to the understanding of great works of art or literature. Despite its inherent limitations stemming from the lack of an actual meeting with the patient, character analyses of heroes of dramatic plays or art works is part of the history of psychoanalysis. This work argues for the possible advantages of the use of psychoanalysis to the understanding of enigmatic behaviors of biblical central figures. Ancient rabbinic midrash is suggested as an auxiliary tool that help to uncover unconscious layers of the biblical text. This work uses the enigmatic story of the binding of Isaac and the exegetical midrash about it as an example for such a work. A clinical vignette demonstrates the potential utilization of this analytic interpretation for clinical work and for the teaching of complicated psychoanalytic concepts. Copyright © 2012 John Wiley & Sons, Ltd.
Lack of Tir Ubiquitylation Contributes to Enteropathogenic E. coli Remaining Extracellular During Nonphagocytic Cell Infections
Authors: Lin Ann E. , Guttman Julian A. 
Published: July 2012

AbstractEnteropathogenic Escherichia coli (EPEC) is an extracellular pathogen that alters many host subcellular components during its infectious processes. We have previously shown that EPEC hijacks a large assortment of host cell endocytic components and uses these proteins to form protruding structures called “pedestals” rather than triggering internalization of the bacteria. Other invasive pathogens that also recruit similar endocytic components have been shown to enter their host cells on the ubiquitylation of their host cell receptors. Therefore, we hypothesize that EPEC remains extracellular by maintaining its receptor, translocated intimin receptor (Tir), in an unubiquitylated state. Using immunoprecipitation‐Western blots, we demonstrate no association of ubiquitin with Tir. To further elucidate the effect Tir ubiquitylation would have on EPEC during their infections, we engineered Tir‐ubiquitin fusion constructs, expressed them in host epithelial cells, and infected them with Δtir EPEC. We found these cells induced a significant increase in EPEC invasion as compared with cells that expressed the Tir construct that lacked ubiquitin conjugation. Our results indicate that the lack of EPEC receptor ubiquitylation is a contributing factor that these microbes use to prevent their internalization into epithelial cells. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
A Distributed State Estimation Approach to Condition Monitoring of Nonlinear Electric Power Systems
Authors: Rigatos G. , Siano P. , Zervos N. 
Published: July 2012

AbstractThis paper analyzes distributed state estimation methods for condition monitoring of electric power transmission and distribution systems. When a fault occurs in such large‐scale systems, it is usually difficult to detect it and to determine its exact position. Moreover, due to the cost of installation and maintenance of measurement devices and due to the excessive size of the electric power grid, the complete monitoring of the associated infrastructure is impractical. Therefore, to monitor the condition of the power grid, some form of estimation is required. As suitable approaches for distributed state estimation this paper proposes the extended information filter (EIF) and the unscented information filter (UIF). The Extended Information Filter is actually an implementation of distributed extended Kalman filtering while the unscented information filter is an implementation of distributed unscented Kalman filtering. With the use of the aforementioned filtering algorithms on processing units located at different parts of the power grid, one can produce local estimates of the system's state vector which in turn can be fused into an aggregate state estimation. The produced global state estimate enables continuous monitoring of the condition of the electric power system and early fault diagnosis if used by a suitable fault detection and isolation algorithm.