Conduit Dimensions Research Articles

Association of conduit dimensions with perioperative outcomes and long-term quality of life after esophagectomy for malignancy

ObjectiveThe impact of conduit dimensions and location of esophagogastric anastomosis on long-term quality of life after esophagectomy remains unexplored. We investigated the association of these parameters with surgical outcomes and patient-reported quality of life at least 18 months after esophagectomy. MethodsWe identified all patients who underwent esophagectomy for cancer from 2018 to 2020 in our institution. We reviewed each patient's initial postoperative computed tomography scan measuring the gastric conduit's greatest width (centimeters), linear staple line length (centimeters), and relative location of esophagogastric anastomosis (vertebra). Quality of life was ascertained using patient-reported outcome measures. Perioperative complications, length of stay, and mortality were collected. Multivariate regressions were performed. ResultsOur study revealed that a more proximal anastomosis was linked to an increased risk of pulmonary complications, a lower recurrence rate, and greater long-term insomnia. Increased maximum intrathoracic conduit width was significantly associated with trouble enjoying meals and reflux long term after esophagectomy. A longer conduit stapled line correlated with fewer issues related to insomnia, improved appetite, less dysphagia, and significantly enhanced “social,” “role,” and “physical'” aspects of the patient's long-term quality of life. ConclusionsThe dimensions of the gastric conduit and the height of the anastomosis may be independently associated with outcomes and long-term quality of life after esophagectomy for cancer.

Discussion to: Association of conduit dimensions with perioperative outcomes and long-term quality of life after esophagectomy for malignancy

Discussion to: Association of conduit dimensions with perioperative outcomes and long-term quality of life after esophagectomy for malignancy

Wood density relates negatively to maximum plant height across major angiosperm and gymnosperm orders.

Wood density is a crucial plant functional trait related to plant life history strategies. Its ecological importance in small-stature growth forms (e.g., shrubs) has not been extensively examined. Given that hydraulic conduit dimensions vary positively with plant height and that there is a negative relationship between conduits' diameter and wood density, I hypothesized an also negative relationship between wood density and plant height. Knowing that bark and pith proportions are significant in small-diameter stems, I additionally disentangled the contribution of wood, bark, and pith to stem density. I determined density in small-diameter stems across 153 species spanning all major angiosperm and gymnosperm orders by considering a diversity of growth forms (trees, treelets, shrubs, vines, and hemiparasites). Stem cross sections were dissected to consider the densities of wood with bark and pith; wood with pith and without bark; wood with bark and no pith; and wood without bark and pith. Secondary growth was also measured. Trees showed similar wood densities as non-self-supporting vines, and both showed significantly less dense wood than treelets, shrubs, and hemiparasites. General comparisons showed that wood was significantly denser than all other tissues, and these differences did not depend on growth form. Wood density was significantly and negatively related to growth rate and pith area proportions but not to bark thickness proportion. An implicit negative relationship between maximum plant height and stem density emerges as a property of plants likely linked to hydraulic conductive size.

Ultrasound Pulse Emission Spectroscopy Method to Characterize Xylem Conduits in Plant Stems.

Although it is well known that plants emit acoustic pulses under drought stress, the exact origin of the waveform of these ultrasound pulses has remained elusive. Here, we present evidence for a correlation between the characteristics of the waveform of these pulses and the dimensions of xylem conduits in plants. Using a model that relates the resonant vibrations of a vessel to its dimension and viscoelasticity, we extract the xylem radii from the waveforms of ultrasound pulses and show that these are correlated and in good agreement with optical microscopy. We demonstrate the versatility of the method by applying it to shoots of ten different vascular plant species. In particular, for Hydrangea quercifolia, we further extract vessel element lengths with our model and compare them with scanning electron cryomicroscopy. The ultrasonic, noninvasive characterization of internal conduit dimensions enables a breakthrough in speed and accuracy in plant phenotyping and stress detection.

Tracheid and Pit Dimensions Hardly Vary in the Xylem of Pinus sylvestris Under Contrasting Growing Conditions.

Maintaining sufficient water transport via the xylem is crucial for tree survival under variable environmental conditions. Both efficiency and safety of the water transport are based on the anatomical structure of conduits and their connections, the pits. Yet, the plasticity of the xylem anatomy, particularly that of the pit structures, remains unclear. Also, trees adjust conduit dimensions to the water transport distance (i.e., tree size), but knowledge on respective adjustments in pit dimensions is scarce. We compared tracheid traits [mean tracheid diameter d, mean hydraulic diameter dh, cell wall reinforcement (t/b)2], pit dimensions (diameters of pit aperture Da, torus Dt, margo Dm, and pit border Dp), and pit functional properties (margo flexibility F, absolute overlap Oa, torus overlap O, and valve effect Vef) of two Scots pine (Pinus sylvestris L.) stands of similar tree heights but contrasting growth rates. Furthermore, we analyzed the trends of these xylem anatomical parameters across tree rings. Tracheid traits and pit dimensions were similar on both sites, whereas Oa, O, and F were higher at the site with a lower growth rate. On the lower growth rate site, dh and pit dimensions increased across tree rings from pith to bark, and in trees from both sites, dh scaled with pit dimensions. Adjusted pit functional properties indicate slightly higher hydraulic safety in trees with a lower growth rate, although a lack of major differences in measured traits indicated overall low plasticity of the tracheid and pit architecture. Mean hydraulic diameter and pit dimension are well coordinated to increase the hydraulic efficiency toward the outer tree rings and thus with increasing tree height. Our results contribute to a better understanding of tree hydraulics under variable environmental conditions.

Peduncle vulnerability to embolism is related to conduit dimensions of the critically endangered slipper orchids in Southwest China

Members of the family Orchidaceae are amongst the most ornamental and protected plants in the world. The understanding of physiological and ecological characteristics of orchids is of great significance for predicting their response to environmental changes and establishing orchid conservation strategies. The physiological characteristics of flowers affect their relationship with pollinators and successful plant reproduction, but research on water physiology of flowers is still lacking. Cypripedium and Paphiopedilum are closely related phylogenetically in Orchidaceae, but they are different in floral longevity, life history, and habitat. In this study, we used the optical vulnerability method to investigate differences in flower peduncle drought resistance in the four slipper orchids of Cypripedium and Paphiopedilum, which are critically endangered orchids in Southwest China, and to test whether peduncle conduit dimensions determine embolism resistance. We found that the peduncles of Paphiopedilum species had greater xylem embolism resistance than that of Cypripedium. Across species, the time of 50% embolism of the peduncles was strongly correlated with the mean ratio (t/b)3 in peduncles. Our results are in line with habitat-based expectations that flower peduncle embolism resistance and conduit traits in Paphiopedilum species has helped them adapt to seasonal drought stress in karst habitats. However, the peduncle traits of Cypripedium reflect adaptations to an environment characterized by abundant soil water during the flowering period. Moreover, drought resistance of the flower peduncle was related to conduit dimensions. The results of this study contribute to our understanding of the divergent adaptation of flower traits in slipper orchids, which is beneficial for the conservation of endangered orchids.

Analysis and stochastic simulation of geometrical properties of conduits in karstic networks

Despite intensive explorations by speleologists, karstic systems remain only partially described as many conduits are not accessible to humans. The classical exploration techniques produce sparse data, leading to various uncertainties about the conduit dimensions, essential parameters for flow simulations.Stochastic simulations offer a possibility to better assess these uncertainties. In this paper, we propose different methods to stochastically simulate the properties (size and shape anisotropy) of karstic conduits on already existing skeletons. These approaches, based on Sequential Gaussian Simulations (SGS), allow taking different conditioning data into account, while respecting the intricacy of the networks.To infer the input parameters, we perform a statistical study of the conduit dimensions of 49 explored karstic networks, focusing on their equivalent radius and width-height ratio. Thanks to the definition of 1D-curvilinear variograms, we demonstrate the existence of a spatial correlation along the networks, which is even higher when considering independently each conduit. Finally, using ad hoc algorithms implemented for computing both a conduit hierarchy inside karstic networks and a relative position regarding outputs, we find no evidence of an obvious link between these two entities and the studied metrics.The simulation methods are then demonstrated on the karstic network of Arrestelia (Pyrénées-Atlantiques, France), and show the consistency of the proposed approach with the observations made on the explored natural systems.

A Physical Model for Volcanic Eruption Tremor

AbstractSeismic waves are commonly used to monitor unrest before, during, and after volcanic eruptions. The source of seismic tremor during a sustained explosive volcanic eruption is not well understood. Recent observations of the 2016 eruption of Pavlof Volcano, Alaska, revealed a change in the relationship (hysteresis) between ash plume height and seismic amplitude over time. Based on similarities in physical processes and observed seismic tremor in rivers, we explore two key sources of seismic energy in the volcanic conduit: (1) forces exerted by particle impacts and (2) dynamic pressure changes by the turbulent flow. We develop a physical model calculating the seismic power spectral density (PSD), where forces on the conduit wall are convolved with the Green's function for Rayleigh waves. Using reasonable eruption parameters, the model is able to reproduce the frequency spectrum from the Pavlof eruption, although the modeled amplitudes are generally lower. We test the relative importance of different eruption parameters, including grain size, velocity, and conduit dimensions. We find that turbulence generally dominates over particle impacts. However, to reach the PSD amplitude during the Pavlof eruption, large grain sizes are required, as they have the greatest relative influence on the modeled amplitude. The hysteresis between plume height and seismic amplitude can then potentially be explained by grain size changes. The PSD shape is mostly determined by the Rayleigh‐wave quality factor Q, and substantial variations in seismic amplitude can be modeled assuming a constant mass eruption rate.

Post-fire effects on development of leaves and secondary vascular tissues in Quercus pubescens.

An increased frequency of fire events on the Slovenian Karst is in line with future climate change scenarios for drought-prone environments worldwide. It is therefore of the utmost importance to better understand tree-fire-climate interactions for predicting the impact of changing environment on tree functioning. To this purpose, we studied the post-fire effects on leaf development, leaf carbon isotope composition (δ13C), radial growth patterns and the xylem and phloem anatomy in undamaged (H-trees) and fire-damaged trees (F-trees) of Quercus pubescens Willd. with good resprouting ability in spring 2017, the growing season after a rangeland fire in August 2016. We found that the fully developed canopy of F-trees reached only half of the leaf area index values measured in H-trees. Throughout the season, F-trees were characterized by higher water potential and stomatal conductivity and achieved higher photosynthetic rates compared to unburnt H-trees. The foliage of F-trees had more negative δ13C values than those of H-trees. This reflects that F-trees less frequently meet stomatal limitations due to reduced transpirational area and more favourable leaf-to-root ratio. In addition, the growth of leaves in F-trees relied more on the recent photosynthates than on reserves due to the fire disturbed starch accumulation in the previous season. Cambial production stopped 3weeks later in F-trees, resulting in 60 and 22% wider xylem and phloem increments, respectively. A novel approach by including phloem anatomy in the analyses revealed that fire caused changes in conduit dimensions in the early phloem but not in the earlywood. However, premature formation of the tyloses in the earlywood vessels of the youngest two xylem increments in F-trees implies that xylem hydraulic integrity was also affected by heat. Analyses of secondary tissues showed that although xylem and phloem tissues are interlinked changes in their transport systems due to heat damage are not necessarily coordinated.

Scaling of phloem hydraulic resistance in stems and leaves of the understory angiosperm shrub Illicium parviflorum.

Recent studies in canopy-dominant trees revealed axial scaling of phloem structure. However, whether this pattern is found in woody plants of the understory, the environment of most angiosperms from the ANA grade (Amborellales-Nymphaeales-Austrobaileyales), is unknown. We used seedlings and adult plants of the understory tropical shrub Illicium parviflorum, a member of the lineage Austrobaileyales, to explore the anatomy and physiology of the phloem in their aerial parts, including changes through ontogeny. Adult plants maintain a similar proportion of phloem tissue across stem diameters, but larger conduit dimensions and number cause the hydraulic resistance of the phloem to decrease toward the base of the plant. Small sieve plate pores resulted in an overall higher sieve tube hydraulic resistance than has been reported in other woody angiosperms. Sieve elements increase in size from minor to major leaf veins, but were shorter and narrower in petioles. The low carbon assimilation rates of seedlings and mature plants contrasted with a 3-fold higher phloem sap velocity in seedlings, suggesting that phloem transport velocity is modulated through ontogeny. The overall architecture of the phloem tissue in this understory angiosperm shrub scales in a manner consistent with taller trees that make up the forest canopy. Thus, the evolution of larger sieve plate pores in canopy-dominant trees may have played a key role in allowing woody angiosperms to extend beyond their understory origins.

3D bioprinting of heterogeneous bi- and tri-layered hollow channels within gel scaffolds using scalable multi-axial microfluidic extrusion nozzle

One of the primary focuses in recent years in tissue engineering has been the fabrication and integration of vascular structures into artificial tissue constructs. However, most available methodologies lack the ability to create multi-layered concentric conduits inside natural extracellular matrices (ECMs) and gels that replicate more accurately the hierarchical architecture of biological blood vessels. In this work, we present a new microfluidic nozzle design capable of multi-axial extrusion in order to 3D print and pattern bi- and tri-layered hollow channel structures. This nozzle allows, for the first time, for these structures to be embedded within layers of gels and ECMs in a fast, simple and low-cost manner. By varying flow rates (1–6 ml min−1), printspeeds (1–16 m min−1), and material concentration (25–175 mM and 1.5%–2.5% for calcium chloride and alginate, respectively) we are able to accurately determine the operational printing range as well as achieve a wide range of conduit dimensions (0.69–2.31 mm) that can be printed within a few seconds. Our scalable design allows for multi-axial extrusion and versatility in material incorporation in order to create heterogeneous structures. We demonstrate the ability to print distinct concentric layers of different cell types, namely endothelial cells and fibroblasts. By incorporating various layers of different cell-friendly materials (such as collagen and fibrin) alongside materials with high mechanical strength (i.e. alginate), we were able to increase long-term cell viability and growth without compromising the structural integrity. In this way, we can improve cellular adhesion in our biocompatible constructs as well as allow them to remain structurally sound. We are able to realize complex heterogeneous, hierarchical architectures that have strong potential for use not only in vascular tissue applications, but also in other artificially fabricated tubular or fiber-like structures such as skeletal muscle or nerve conduits.

Morphology, Effusion Rates, and Petrology of Postglacial Lavas of Laguna del Maule Volcanic Field, Chilean Andes, and Implications for Their Plumbing System

AbstractWe analyzed the dimensions, morphology, and petrography of nine postglacial lava flows, ranging from andesites to rhyolites, located at the Laguna del Maule Volcanic Field in the Southern Andes of Chile. Our data were used in conjunction with theoretical models of magma ascent and lava flow advance to estimate time scales of lava emplacement, effusion rates, magma chamber volume, and conduit dimensions. The results indicate that the parameters of these past eruptions correspond to eruptions of months to a few years in duration, with peak effusion rates <100 m3/s, and were fed by magma chambers of 6 to 30 km3 and conduits of radius 20 to 70 m. Thermobarometric results indicate crystallization pressures between 260 and 450 MPa and temperatures of 780 to 1060 °C for the analyzed units. These results, taken together with recent geophysical studies, suggest that the most likely scenario, in case of an eruption, corresponds to a medium size eruption (0.1–1 km3). Initial activity would be explosive, followed by the extrusion of lava flows that can last several months.

Leaf vein xylem conduit diameter influences susceptibility to embolism and hydraulic decline.

Ecosystems worldwide are facing increasingly severe and prolonged droughts during which hydraulic failure from drought-induced embolism can lead to organ or whole plant death. Understanding the determinants of xylem failure across species is especially critical in leaves, the engines of plant growth. If the vulnerability segmentation hypothesis holds within leaves, higher order veins that are most terminal in the plant hydraulic system should be more susceptible to embolism to protect the rest of the water transport system. Increased vulnerability in the higher order veins would also be consistent with these experiencing the greatest tensions in the plant xylem network. To test this hypothesis, we combined X-ray micro-computed tomography imaging, hydraulic experiments, cross-sectional anatomy and 3D physiological modelling to investigate how embolisms spread throughout petioles and vein orders during leaf dehydration in relation to conduit dimensions. Decline of leaf xylem hydraulic conductance (Kx ) during dehydration was driven by embolism initiating in petioles and midribs across all species, and Kx vulnerability was strongly correlated with petiole and midrib conduit dimensions. Our simulations showed no significant impact of conduit collapse on Kx decline. We found xylem conduit dimensions play a major role in determining the susceptibility of the leaf water transport system during strong leaf dehydration.

A fuzzy approach to reliability based design of storm water drain network

This paper proposes an approach to estimate reliability of a storm water drain (SWD) network in fuzzy framework. It involves: (i) use of proposed fuzzy Monte-Carlo simulation (FMCS) methodology to estimate fuzzy reliability of conduits in the network, (ii) construction of a reliability block diagram (RBD) for the network (system) using suggested guidelines, and (iii) use of the RBD and reliability estimates of the conduits in the network to compute system reliability based on a proposed procedure. In addition, a system reliability based methodology is proposed for design/retrofitting of SWD network by optimization of its conduit dimensions. Conventionally used reliability analysis approaches assume that the cumulative distribution function (CDF) of performance function (marginal safety) of conduits follows Gaussian distribution, which cannot be ensured in the real world scenario. The proposed approach alleviates the need for making such assumptions and can account for linguistic ambiguity in variables defining the performance function. Effectiveness of the proposed approach is demonstrated on a hypothetical SWD network and a real network in Bangalore, India. Comparison of the results obtained from the proposed approach with those from conventional Monte-Carlo simulation (MCS) reliability assessment approach indicated that the estimate of system reliability and conduit reliability are higher with FMCS approach. Consequently, conduit dimensions required to attain required system (network) reliability could be expected to be lower when FMCS approach is used for designing or retrofitting a system.

Shallow crustal mechanics from volumetric strain data: Insights from Soufrière Hills Volcano, Montserrat

AbstractVolumetric strain data from the 29 July 2008 Vulcanian explosion of the Soufrière Hills Volcano provide an excellent opportunity to probe the mechanical properties of the volcanic edifice and the shallow crust beneath Montserrat. We use Finite Element Analysis to constrain the geometry of the shallow plumbing system as well as edifice and crustal mechanical properties for mechanically plausible pressure drops associated with dilatational volumetric strains recorded during the explosive activity. Our results from both forward and inverse models indicate a conduit radius of ∼40 m and a length of ∼1500 m, and hence much larger conduit dimensions than previously suggested. In order to fit the syneruptive volumetric strain data for a conduit pressure drop of <10 MPa, the conduit needs to be surrounded by a halo of mechanically compliant rocks for which the best fit models indicate a width of ∼600 m and a Young's modulus of ∼1 GPa. Young's moduli for the main edifice and the shallow crust up to ∼1000 m below sea level are found to be ∼10 GPa. Our best fit inverse model predicts a syneruptive radial conduit contraction by 0.24 m with a corresponding volume loss of ∼0.1 Mm3, implying only partial emptying of the conduit upon the explosion. This study demonstrates the critical role of edifice and shallow crustal mechanics for strain partitioning on Montserrat. Our findings may have implications for the assessment of conduit processes at other dome‐building volcanoes.

Reliability Assessment of a Storm Water Drain Network

Most of the cities in India are undergoing rapid development in recent decades, and many rural localities are undergoing transformation to urban hotspots. These developments have associated land use/land cover (LULC) change that effects runoff response from catchments, which is often evident in the form of increase in runoff peaks, volume and velocity in drain networ k. Often most of the existing storm water drains are in dilapidated stage owing to improper maintenance or inadequate design. The drains are conventionally designed using procedures that are based on some anticipated future conditions. Further, values of parameters/variables associated with design of the network are traditionally considered to be deterministic. However, in reality, the parameters/variables have uncertainty due to natural and/or inherent randomness. There is a need to consider the uncertainties for designing a storm water drain network that can effectively convey the discharge. The present study evaluates performance of an existing storm water drain network in Bangalore, India, through reliability analysis by Advance First Order Second Moment (AFOSM) method. In the reliability analysis, parameters that are considered to be random variables are roughness coefficient, slope and conduit dimensions. Performance of the existing network is evaluated considering three failure modes. The first failure mode occurs when runoff exceeds capacity of the storm water drain network, while the second failure mode occurs when the actual flow velocity in the storm water drain network exceeds the maximum allowable velocity for erosion control, whereas the third failure mode occurs when the minimum flow velocity is less than the minimum allowable velocity for deposition control. In the analysis, runoff generated from subcatchments of the study area and flow velocity in storm water drains are estimated using Storm Water Management Model (SWMM). Results from the study are presented and discussed. The reliability values are low under the three failure modes, indicating a need to redesign several of the conduits to improve their reliability. This study finds use in devising plans for expansion of the Bangalore storm water drain system.

COMPUTATIONAL MODEL TO DESIGN CIRCULAR RUNNER CONDUIT FOR PLASTIC INJECTION MOULD

Analytical solution quest for viscoelastic shear th inning fluid flow through circular conduit is a mat ter of great prominence as it directly evolvesmost efficient criteria to investigate various responses of independent parameters. En visaging this facet present endeavour attempts to develop a computational model for designing runner conduit lateral dimension in a plastic injection mould through which thermoplastic melt gets injected. At outset injection phenomenon is represented by gover ning equations on the basis of mass, momentum and energy conservation principles [ 1]. Embracing Hagen Poiseuille flow problem analogo us to runner conduit injection the manuscript uniquely imposes runner co nduit inlet and outlet boundary conditions along wi th relative to appropriate assumptions; governing equations evolve a computati on model as criteria for designing. To overwhelm No n-Newtonian’s abstruse Weissenberg-Rabinowitsch correction factor has been adopted byaccommodating thermoplastic melt behavio ur towards the final stage of derivation. The resulting final computatio nal model is believed to express runner conduit dim ensions as a function of available type of injection moulding machine specif ications, characteristics of thermoplastic melt and required features of component being moulded. Later the equation so obtained has bverified by using dimensional analysis method .

Xylem anatomy and calculated hydraulic conductance of four Nothofagus species with contrasting distribution in South-Central Chile

Nothofagus obliqua, N. dombeyi, N. alpina and N. antarctica are characteristic tree species of the temperate forests on the western slopes of the Andes with centres of distribution that differ in their temperature and moisture regimes. We tested branch wood from co-occurring specimens of these species for the inherent differences in xylem anatomy and theoretical hydraulic conductance to evaluate their resistance to drought or frost. The hydraulic conductivity of the xylem was calculated using a modified Hagen–Poiseuille equation and related to wood density. Conduit dimensions were used to predict the water potential that would cause 50 % loss of hydraulic conductivity (Ψ 50). Nothofagus alpina, which mainly grows at sites with low frost frequency, exhibited the largest conduits and the highest mean values for conduit area, fraction of conduit area in the cross-section and hydraulic conductivity, but the lowest wood density. Opposite relationships were found in the plastic N. antarctica, whose xylem seems to be least vulnerable to freezing-induced, but also to drought-induced embolism. Calculated Ψ 50 was highest (least negative) in N. alpina, indicating a relatively high susceptibility to cavitation. The xylem of the thermophilic N. obliqua and of N. dombeyi, which mainly occurs under oceanic climate, but can also survive at sporadically dry and warm sites, is not particularly adapted to periods of drought stress. Across all species, wood density was negatively correlated with the calculated hydraulic conductance. The xylem traits of N. alpina might contribute to its relatively high growth rate and facilitate its spread into forest gaps.

Numerical investigation of the effect of geometrical parameters on the performance of a micro-reactor

Micro-reactors offer significant advantages over conventional reactors. Due to the small conduit dimensions the flow is usually laminar and the extent of the chemical reactions is governed by the slow diffusive mass transfer, which in turn is controlled by the extent of mixing. In this study, a prototype μ-reactor, which comprises several features that are known to promote chaotic mixing, i.e., curved conduits, split-and-recombine structures, as well as backward and forward facing steps were numerically studied. A Design-of-Experiments ( DOE) method is used for the selection of appropriate design points. The various configurations are then studied by performing computational fluid dynamics ( CFD) simulations. The extent of mixing is investigated by monitoring the Residence Time Distribution ( RTD) of a tracer introduced into the flow and observing the shape of the RTD curves. The effect of Re as well as the curvature of the conduits on mixing efficiency and pressure drop has been studied. RTDs constructed for the various geometrical configurations and Re values were compared and discussed. As expected, mixing efficiency is increased by increasing the curvature of the conduit and/or Re. Quadratic models for mixing efficiency and pressure drop are proposed and can be used to design the optimal μ-reactor for the required pumping power.

The Early and Midterm Function of Decellularized Aortic Valve Allografts

This study evaluates the early and midterm results of decellularized aortic valve allografts (DAVA) as an aortic valve replacement. Between October 2005 and February 2010, 41 patients, 28 of whom were male, with a median age of 34 years (range, 0.1 to 71), had aortic valve replacement with DAVA. Decellularization was obtained with a 0.1% sodium dodecyl sulfate solution. Postoperative evaluation was performed with serial echocardiograms, magnetic resonance imaging, and multislice computed tomography studies to evaluate valve hemodynamics, allograft conduit dimensions, and calcification scores. There were 3 early deaths and 1 late death, with a mean follow-up of 19 months (range, 1 to 53). There was 1 reoperation due to a failed mitral valve repair. By echocardiography in all patients, the median immediate postoperative peak gradient was 7 mm Hg (range, 1 to 26 mm Hg), and at last follow-up it was 4 mm Hg (range, 1 to 16 mm Hg); valvular regurgitation was graded as none or trivial in all but 1 patient, who had a regurgitation graded as mild to moderate. By magnetic resonance imaging (n = 4), mean root dimensions were stable at the annulus (24 mm), sinus of Valsalva (33 mm), and sinotubular junction (28 mm). By computed tomography (n = 22), there was only discrete conduit calcification (median calcium score 63 Hounsfield units [HU]; range, 0 to 894 HU) to 3 years of follow-up. Conduit biopsy in the patient who underwent reoperation demonstrated well-preserved wall structure, absence of calcification, and limited in vivo host repopulation. The early and midterm results with DAVA demonstrated stable structural integrity, low rate of calcification, and adequate hemodynamics. Although longer periods of observation are necessary, DAVA appears to be a promising alternative for aortic valve replacement in selected patients.