Partial Reconstructions Research Articles

Paleomagnetism‐Based Chronology of Holocene Lava Flows at Mt Ruapehu, Aotearoa New Zealand

AbstractDating young lava flows is essential for understanding volcano's eruption frequency, yet challenging due to methodological limitations of commonly used dating techniques. Ruapehu (Aotearoa New Zealand) produced many lava flows during the Holocene, but constraints on the timing of these eruptions are scarce. Here, we use paleomagnetic dating to deliver new eruption ages of 18 lava flows with uncertainties ranging between 500 and 2,700 years (at the 95% confidence level). Comparison between lava flows' paleomagnetic directions and a local paleosecular variation record indicates that the large lava flow field located on the Whakapapa area was emplaced during at least three distinct eruptive episodes between 10600 and 7400 BP. Two of these episodes closely followed a large collapse event that affected Ruapehu's northern area and generated large volumes of lava between 10600 and 8800 BP, with the third episode producing less voluminous lava flows between 8100 and 7400 BP. Following a smaller collapse of the southeastern sector of the edifice at ca. 5300 BP, several low‐volume lava flows were emplaced during at least two distinct eruptive episodes prior to ca. 1000 BP, which supplied the Whangaehu valley with lava. The youngest age inferred from our data represents the youngest eruption age provided for a lava flow outside Ruapehu's summit region. This research provides greater detail to the Holocene effusive chronology at Ruapehu, shedding light on partial cone reconstructions after edifice collapses during the Holocene, and the time relationships between trends observed in its effusive and explosive activity.

Vessel-targeted compensation of deformable motion in interventional cone-beam CT

The present standard of care for unresectable liver cancer is transarterial chemoembolization (TACE), which involves using chemotherapeutic particles to selectively embolize the arteries supplying hepatic tumors. Accurate volumetric identification of intricate fine vascularity is crucial for selective embolization. Three-dimensional imaging, particularly cone-beam CT (CBCT), aids in visualization and targeting of small vessels in such highly variable anatomy, but long image acquisition time results in intra-scan patient motion, which distorts vascular structures and tissue boundaries. To improve clarity of vascular anatomy and intra-procedural utility, this work proposes a targeted motion estimation and compensation framework that removes the need for any prior information or external tracking and for user interaction. Motion estimation is performed in two stages: (i) a target identification stage that segments arteries and catheters in the projection domain using a multi-view convolutional neural network to construct a coarse 3D vascular mask; and (ii) a targeted motion estimation stage that iteratively solves for the time-varying motion field via optimization of a vessel-enhancing objective function computed over the target vascular mask. The vessel-enhancing objective is derived through eigenvalues of the local image Hessian to emphasize bright tubular structures. Motion compensation is achieved via spatial transformer operators that apply time-dependent deformations to partial angle reconstructions, allowing efficient minimization via gradient backpropagation. The framework was trained and evaluated in anatomically realistic simulated motion-corrupted CBCTs mimicking TACE of hepatic tumors, at intermediate (3.0 mm) and large (6.0 mm) motion magnitudes. Motion compensation substantially improved median vascular DICE score (from 0.30 to 0.59 for large motion), image SSIM (from 0.77 to 0.93 for large motion), and vessel sharpness (0.189 mm−1 to 0.233 mm−1 for large motion) in simulated cases. Motion compensation also demonstrated increased vessel sharpness (0.188 mm−1 before to 0.205 mm−1 after) and reconstructed vessel length (median increased from 37.37 to 41.00 mm) on a clinical interventional CBCT. The proposed anatomy-aware motion compensation framework presented a promising approach for improving the utility of CBCT for intra-procedural vascular imaging, facilitating selective embolization procedures.

‘I know how to live from what the hill gives’: biocultural uses, tensions and partial reconstructions around the common goods of the Cerro Caracol urban park

Abstract In the south-central Chilean city of Concepción, an irregular urban settlement named ‘Agüita de la Perdiz’ (Partridge Creek) built on the slopes of Cerro Caracol (Snail Hill) has become an emblematic neighbourhood, located within an urban biodiversity hotspot. The richness and biodiversity of the landscape have been used in different ways by the inhabitants of Concepción, but in the case of the Agüita de la Perdiz residents, it is also part of their way of life, representing an unusual people–nature relationship in urban spaces. We analyze the relationship between the community and the hill, with its forest, fauna, waters and recreational areas; the successive territorial dispossessions and the various conflicts involved in the operation of the Metropolitan Park, created to protect the hill; and the efforts led by community members to recompose their relationship with the hill. The case problematizes urban bioculture, from a political ecology of commons perspective, and co-management approaches for conservation.

TC-SfM: Robust Track-Community-Based Structure-from-Motion.

Structure-from-Motion (SfM) aims to recover 3D scene structures and camera poses based on the correspondences between input images, and thus the ambiguity caused by duplicate structures (i.e., different structures with strong visual resemblance) always results in incorrect camera poses and 3D structures. To deal with the ambiguity, most existing studies resort to additional constraint information or implicit inference by analyzing two-view geometries or feature points. In this paper, we propose to exploit high-level information in the scene, i.e., the spatial contextual information of local regions, to guide the reconstruction. Specifically, a novel structure is proposed, namely, track-community, in which each community consists of a group of tracks and represents a local segment in the scene. A community detection algorithm is performed on the track-graph to partition the scene into segments. Then, the potential ambiguous segments are detected by analyzing the neighborhood of tracks and corrected by checking the pose consistency. Finally, we perform partial reconstruction on each segment and align them with a novel bidirectional consistency cost function which considers both 3D-3D correspondences and pairwise relative camera poses. Experimental results demonstrate that our approach can robustly alleviate reconstruction failure resulting from visually indistinguishable structures and accurately merge the partial reconstructions.

Aesthetic results were more satisfactory after oncoplastic surgery than after total breast reconstruction according to patients and surgeons.

Patient satisfaction after breast cancer surgery has an impact on body image, sexual function, self-esteem, and quality of life and may differ from the perception of the attending physician. This study aimed to compare the aesthetic outcomes and satisfaction with conservative oncoplastic surgeries, mastectomies, and total breast reconstruction. We included 760 women diagnosed with invasive breast carcinoma or phyllodes tumors who returned at least 6 months after surgery or radiotherapy at two public hospitals and a private clinic between 2014 and 2022. Data was collected prospectively from patients and retrospectively from their medical records using a specific form after obtaining their informed consent. Aesthetic outcomes and quality of life were assessed using the BREAST-Q©, Harris Scale, and BCCT.core software. Data were evaluated using the SPSS statistical software. Statistical significance was set at p<0.05. This study was approved by the hospital ethics committees. A total of 405 (53.29%) partial and 355 (46.71%) total reconstructions were included. Patients who underwent partial reconstruction were older and had higher body mass index. Patients who underwent total reconstruction had larger tumors with advanced clinical and pathological stages. Clinical and surgical complications occurred more frequently in the total reconstruction group. A greater number of reparative surgeries and lipofilling procedures were required for total reconstruction. According to the BREAST-Q, the partial reconstruction group showed significantly higher levels of women's satisfaction with their breasts, the surgical outcomes, psychosocial and sexual well-being, provision of information, and the reconstructive surgeon. Only physical well-being was slightly higher in the total reconstruction group. In most cases, the results were rated good or excellent. Physicians considered partial reconstructions to have better results than total reconstructions, although this difference was not perceived by the BCCT.core software. Women who underwent partial breast reconstruction had higher levels of satisfaction in several domains, lower frequency of complications, and required fewer surgeries to complete their reconstruction than women who underwent total reconstruction. Physicians were also more satisfied with the results of partial reconstructions.

VirMAP for cancer: Characterization of the intratumoral virome in virally associated cancers and a resource for investigators.

2568 Background: A major barrier to understanding the role of viruses in cancer progression has been the lack of sensitivity of current tools to assemble viral genomes in an untargeted way. Here, we utilize our novel VirMAP algorithm to identify eukaryotic and prokaryotic viruses associated with cancers, using RNA sequencing data from The Cancer Genome Atlas (TCGA). Methods: VirMAP was run on 16 TCGA RNASeq datasets of primary tumor tissues, with a focus on cancers with known viral associations (including cervical, head and neck, liver, stomach, esophagus and ovarian). Previously published survival data were used for exploratory analysis. Overall survival (OS) was assessed using the Kaplan-Meier method, and p-values were calculated using log-rank test. Multivariate analysis (MVA) was done using Cox proportional hazards model to control for age, sex, stage, and histology. Results: Viral sequence recovery (among 537 billion sequencing reads from 6185 patients) was at least equal to previously published algorithms such as Kraken, but with higher taxonomic resolution; overall recovery was 0.0041% from 16 tumor types. Cancers with high viral loads such as cervical cancer demonstrated high recovery rates (0.012% of all reads mapped to viral taxa, followed by 0.004% for liver, 0.0018% head and neck, 0.0016% stomach, 0.0009% esophageal, and 0.0002% ovarian). There was a wide range of viral signature richness, with cervical cancer showing the highest viral read count predominated by 18 different HPV serotypes; in contrast, stomach cancer had lower abundance but contained over 300 unique viral species. Exploratory analysis revealed novel correlations between viral signatures and OS. In cervical cancer, presence of HPV45 predicted worse survival (median OS 837 days vs 4086, p=0.0043); MVA demonstrated hazard ratio (HR) of 5.7 [2.6-11.4, p&lt;0.0001]. In stomach cancer, patients often had more than one viral taxon present (mean 3.7, range 0-18); presence of seven or more unique taxa predicted worse OS (median OS 403 days vs 1153, p=0.0001). MVA showed HR of 1.1 for every additional taxon (p=0.0004). Across all 16 tumor types, the detection of phage virus was associated with worse OS (1073 days vs. 2094 days for non-phage virus and 2131 days for no virus, p&lt;0.0001). Conclusions: VirMAP performs deep characterization of the tumor-associated virome in both high and low abundance settings, with generation of partial genome reconstructions and strain level taxonomic classification including phages. Further work is ongoing to optimize viral read normalization based on genome length, as well as subset analysis with disease-specific modifiers such as histology, race, and exposures. Utilizing publicly available platforms such as TCGA, clinical and correlative published data can be leveraged to better understand the nuanced pleotropic effects of the tumor virome on cancer progression.

Exclusive endoscopic ossiculoplasty with autologous material: step-by-step procedure and functional results.

To describe the surgical procedure of exclusive endoscopic ossiculoplasty (EEO) with autologous grafts and evaluate audiological results, focusing on the advantages or drawbacks compared to the corresponding microscopic technique. A retrospective review of consecutive adult and pediatric patients affected by chronic otitis media (COM) with or without cholesteatoma who underwent EEO was conducted. Only autologous ossiculoplasty was included in the study. The procedure was performed by experienced surgeons of our institution between November 2014 and September 2019. Hearing outcomes were evaluated using postoperative air-bone gap (ABG) and success rates in different subgroups of patients and different types of ossiculoplasty (OPL) were analyzed. Our results were finally compared with the existing literature regarding both microscopic and endoscopic ossicular chain reconstruction. In total, 74 endoscopic ossicular chain repair procedures performed within the study period met the inclusion criteria. Of these, 21 were pediatric patients (28%) and 53 were adults (72%). Surgical reconstruction procedures included 43 partial ossicular reconstructions (POR) and 31 total ossicular reconstructions (TOR). The postoperative ABG improved significantly compared to preoperative measurements, and the mean ABG closure was 7.85dB HL (p = 0.00064). No statistically significant differences in audiological outcomes between TOR/POR techniques and pediatric/adult groups were found in our study cohort, with p values of 0.10 and 0.88, respectively. At present, EEO can be considered a valid surgical option for re-establishing a functioning ossicular chain with acceptable hearing restoration in children and adults. Further reports in wider case series are required to confirm these results.

Abstract 641: VirMAP for cancer: Characterization of the intratumoral virome in virally-associated cancers and a resource for investigators

Abstract Background: A major barrier to understanding the role of viruses in cancer progression has been the lack of sensitivity of current tools to identify and assemble viral genomes in an untargeted way. Here, we utilize our novel VirMAP algorithm to identify eukaryotic and prokaryotic viruses associated with cancers, using RNA sequencing data from The Cancer Genome Atlas (TCGA). Methods: VirMAP was used to analyze TCGA RNA-Seq data derived from primary tumor tissues, with a focus on cancers with known viral associations (cervical, ovarian, head and neck, liver, stomach and esophagus). Previously published survival data were matched with viral signatures for exploratory analysis. Ancom-BC, a differential abundance pipeline, was utilized to screen for viruses which drive outcome. Overall survival (OS) was assessed using the Kaplan-Meier method, and p-values were calculated using log-rank test. Multivariate analysis (MVA) was done using the Cox proportional hazards model to control for age, sex, stage, and histology. Results: Viral sequence recovery (among 723 billion sequencing reads from 2090 patients) was at least equal to previously published algorithms such as Kraken, but with higher taxonomic resolution. Cancers with high viral loads such as cervical cancer demonstrated high recovery rates (0.012% of all sequencing reads mapped to viral taxa, followed by 0.004% for liver, 0.0018% for head and neck squamous cell, 0.0016% for stomach, 0.0009% for esophageal, and 0.0002% for ovarian). There was a wide range of viral signature richness, with cervical cancer showing the highest viral read count predominated by HPV serotypes; in contrast, stomach cancer had lower abundance but contained over 300 unique viral taxa. Exploratory clinical analysis revealed novel correlations between viral signatures and OS. In cervical cancer, presence of HPV45 predicted worse survival (median OS 837 days vs 4086, p=0.0043); MVA demonstrated hazard ratio (HR) of 5.7 [2.6-11.4, p&amp;lt;0.0001]. In stomach cancer, patients often had more than one viral taxon present (mean 3.7, range 0-18); presence of 7 or more unique taxa predicted worse OS (median OS 403 days vs 1153, p=0.0001). MVA showed HR 1.1 for every additional taxon (p=0.0004). Conclusions: VirMAP performs deep characterization of the tumor-associated virome in both high and low abundance settings, with generation of partial genome reconstructions and strain level taxonomic classification. Utilizing publicly available platforms such as TCGA, clinical and correlative published data can be leveraged to better understand the nuanced pleotropic effects of the tumor virome on cancer progression. Citation Format: Yongwoo D. Seo, Neal Bhutiani, Matthew C. Wong, Ashish V. Damania, Golnaz Morad, Matthew Lastrapes, Alexander J. Lazar, Jennifer A. Wargo, Nadim J. Ajami. VirMAP for cancer: Characterization of the intratumoral virome in virally-associated cancers and a resource for investigators [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 641.

Precision partial scapular bone sarcoma resections and functional reconstructions with 3D printed Patient-Specific implants: Cases report

Precision partial scapular bone sarcoma resections and functional reconstructions with 3D printed Patient-Specific implants: Cases report

INV-Flow2PoseNet: Light-Resistant Rigid Object Pose from Optical Flow of RGB-D Images Using Images, Normals and Vertices.

This paper presents a novel architecture for simultaneous estimation of highly accurate optical flows and rigid scene transformations for difficult scenarios where the brightness assumption is violated by strong shading changes. In the case of rotating objects or moving light sources, such as those encountered for driving cars in the dark, the scene appearance often changes significantly from one view to the next. Unfortunately, standard methods for calculating optical flows or poses are based on the expectation that the appearance of features in the scene remains constant between views. These methods may fail frequently in the investigated cases. The presented method fuses texture and geometry information by combining image, vertex and normal data to compute an illumination-invariant optical flow. By using a coarse-to-fine strategy, globally anchored optical flows are learned, reducing the impact of erroneous shading-based pseudo-correspondences. Based on the learned optical flows, a second architecture is proposed that predicts robust rigid transformations from the warped vertex and normal maps. Particular attention is paid to situations with strong rotations, which often cause such shading changes. Therefore, a 3-step procedure is proposed that profitably exploits correlations between the normals and vertices. The method has been evaluated on a newly created dataset containing both synthetic and real data with strong rotations and shading effects. These data represent the typical use case in 3D reconstruction, where the object often rotates in large steps between the partial reconstructions. Additionally, we apply the method to the well-known Kitti Odometry dataset. Even if, due to fulfillment of the brightness assumption, this is not the typical use case of the method, the applicability to standard situations and the relation to other methods is therefore established.

Off-axis propagation algorithm for partial reconstruction of wide-angle computer-generated holograms.

A method for reconstruction of partial off-axis areas of arbitrary size for wide-angle viewing computer generated holograms is presented. Proposed method employs paraxial spherical phase factors and modified propagation kernels. This significantly reduces the numerical space-bandwidth product needed for off-axis wave field calculations, which makes it an efficient propagation method. As a result, propagated wavefields of high-off axis and large size output windows can be obtained. To that end, a phase-space analysis for obtaining the proper condition for implementing spatial-frequency zero-padding for accurate wavefield propagation is carried out. Hence, suppression of aliased components and high spatial resolution is possible. Nevertheless, proposed algorithm faces a computer memory bottleneck when reconstructing very large off-axis areas due to too extensive zero-padding needed. To solve this problem, a memory optimized tiling implementation is introduced. Utility of the developed propagation tools are proven by partial reconstructions from a high-resolution hologram. The size of the reconstructions areas ranges from 100 × 100 mm2 up to 550 × 550 mm2.

Outcomes, Including Graft Tears, Contralateral Anterior Cruciate Ligament Tears, and All-Cause Ipsilateral Knee Operations, are Similar for Adult-type, Transphyseal, and Partial Transphyseal Anterior Cruciate Ligament Reconstruction Using Hamstring Autograft in Pediatric and Adolescent Patients

PurposeTo compare hamstring autograft primary anterior cruciate ligament reconstruction (ACLR) techniques including adult-type/anatomic, transphyseal, and transphyseal techniques by (1) ACL graft tear, (2) contralateral ACL tear, and (3) all-cause ipsilateral reoperation.MethodsA retrospective, single-surgeon review was performed including all ACLR with hamstring autograft in pediatric and adolescent patients from 2011 to 2019. Minimum 2-year follow-up was required for patients unless a tear or reoperation was sustained before that time point. Data collected included demographics and baseline surgical variables, type of reconstruction, sporting activity, and deviations from rehabilitation protocols. Comparisons were made among hamstring autograft reconstruction groups (adult-type/anatomic, transphyseal, and partial transphyseal) for primary outcomes of graft tear, contralateral ACL tears, and all-cause ipsilateral knee reoperations, including hardware removal. Secondary surgeries performed with different surgeons were noted.ResultsIn total, 214 patients of age 15.2 ± 2.0 years with 4.1 ± 1.7-year follow-up were included. Overall graft tear rate was 11.7% (11.0% adult-type vs 19.1% transphyseal vs 5.6% partial transphyseal; P = .18). On univariate analyses, all-cause ipsilateral reoperation did not differ by technique (21.3% vs 31.0% vs 33.3%; P = .20), and neither did contralateral ACL tear (8.1% vs 9.5% vs 0%; P = .17). 21.7% of ipsilateral revision ACLRs (all adult-type) and 16.7% of patients with any reoperations had subsequent procedures performed with a different surgeon.ConclusionsThe graft tear rates in primary hamstring autograft ACLRs in the adolescent population did not significantly differ by technique (11.0% vs 19.1% vs 5.6% in adult-type, transphyseal, and partial transphyseal reconstructions, respectively). Furthermore, contralateral ACL tears (8.1% vs 9.5% vs 0%) and all-cause (including > 1/4 hardware removal) ipsilateral knee reoperations (21.3% vs 31.0% vs 33.3%) did not statistically differ. Higher powered studies may detect statistical significance in the observed differences in this study.Level of evidenceLevel IV, therapeutic case series.

The Khirbet Qeiyafa Ostracon: A New Collation Based on the Multispectral Images, with Translation and Commentary

This paper provides a new collation of the Khirbet Qeiyafa ostracon on the basis of the multispectral images produced by Gregory Bearman and William Christens-Barry in collaboration with a number of imaging labs in 2009. It proposes 59 letters in total, with 12 new readings, including 5 new partial reconstructions, all supported by an analysis of these detailed, high-definition images. This new collation permits a renewed attempt at translation of the ostracon, which is interpreted as a record of the summons of a defendant in a legal dispute. In the course of analysis, it is argued that if the decipherment is accepted, the language of the text appears to be an archaic, dialectal form of Hebrew.

Where Does It Belong? Autonomous Object Mapping in Open-World Settings.

Detecting changes such as moved, removed, or new objects is the essence for numerous indoor applications in robotics such as tidying-up, patrolling, and fetch/carry tasks. The problem is particularly challenging in open-world scenarios where novel objects may appear at any time. The main idea of this paper is to detect objects from partial 3D reconstructions of interesting areas in the environment. In our pipeline we first identify planes, consider clusters on top as objects, and compute their point-pair-features. They are used to match potential objects and categorize them robustly into static, moved, removed, and novel objects even in the presence of partial object reconstructions and clutter. Our approach dissolves heaps of objects without specific object knowledge, but only with the knowledge acquired from change detection. The evaluation is performed on real-world data that includes challenges affecting the quality of the reconstruction as a result of noisy input data. We present the novel dataset ObChange for quantitative evaluation, and we compare our method against a baseline using learning-based object detection. The results show that, even with a targeted training set, our approach outperforms the baseline for most test cases. Lastly, we also demonstrate our method’s effectiveness in real robot experiments.

Motion compensation for aortic valves using partial angle CT reconstructions.

A motion compensation method that is aimed at correcting motion artifacts of cardiac valves is proposed. The primary focus is the aorticvalve. The method is based around partial angle reconstructions and a cost function including the image entropy. A motion model is applied to approximate the cardiac motion in the temporal and spatial domain. Based on characteristic values for velocities and strain during cardiac motion, penalties for the velocity and spatial derivatives are introduced to maintain anatomically realistic motion vector fields and avoid distortions. The model addresses global elastic deformation, but not the finer and more complicated motion of the valve leaflets. The method is verified based on clinical data. Image quality was improved for most artifact-impaired reconstructions. An image quality study with Likert scoring of the motion artifact severity on a scale from 1 (highest image quality) to 5 (lowest image quality/extreme artifact presence) was performed. The biggest improvements after applying motion compensation were achieved for strongly artifact-impaired initial images scoring 4 and 5, resulting in an average change of the scores by and , respectively. In the case of artifact-free images, a chance to introduce blurring was observed and their average score was raised by 0.42 ± 0.03. Motion artifacts were consistently removed and image qualityimproved.

View Path Planning via Online Multiview Stereo for 3-D Modeling of Large-Scale Structures

This study addresses a view-path-planning problem during 3-D scanning of a large-scale structure based on multiview stereo (MVS) for unmanned aerial platforms. Recently, most studies have adopted an explore-then-exploit strategy for 3-D scanning. The strategy first generates a coarse model from a simple overhead scanning and then plans an inspection path to cover the entire surface of the coarse model. However, even though the inspection path may be optimal, it is difficult to guarantee a complete and accurate reconstruction result due to defective factors of MVS such as occlusions, textureless surfaces, and insufficient parallaxes. Furthermore, the entire procedure of this strategy is inefficiently slow because of path redundancies and long MVS processing time. Therefore, we propose a novel view-path-planning method for 3-D scanning based on an online MVS reconstruction algorithm. The suggested method incrementally reconstructs the target model online and iteratively plans view paths by analyzing the current partial reconstructions. The method continuously analyzes the quality of the model and detects inaccurately reconstructed surfaces. It then plans an inspection path that provides a complete coverage of the detected surfaces while maximizing the performance of MVS. This method can construct a complete 3-D model in a single scanning trial without the need for rescanning. Extensive experiments show that our method outperforms the other state-of-the-art methods, especially in terms of the model completeness of complex structures.

Beirut Heritage Initiative: Safeguarding the City’s Built Heritage After the August 4, 2020, Port Explosion

The devastating explosion in Beirut’s port on August 4, 2020 will forever be engraved in the memory of the Lebanese people. Within moments, a city with over 5,000 years of history was in ruins. Aside from the terrible casualties, the blast impacted one of the largest concentrations of heritage buildings in the city, dating from the 19th and 20th centuries. For this reason Beirut Heritage Initiative (BHI) was established in an attempt to help restore the city’s built heritage and to preserve both the urban and the social fabric of the damaged neighborhoods. BHI’s first mission was focused on emergency works such as rapid sheltering and consolidation of damaged buildings to prevent further damage due to the winter weather. After this emergency phase, BHI has engaged in partial reconstructions to enable vulnerable inhabitants to return to their homes, and a third phase has focused on full restoration projects for highly damaged buildings.

Accurate Inlet Boundary Conditions to Capture Combustion Chamber and Turbine Coupling With Large-Eddy Simulation

Abstract The coupling between different components of a turbomachinery is becoming more widely studied especially by use of computational fluid dynamics. Such simulations are of particular interest especially at the interface between a combustion chamber and a turbine, for which the prediction of the migration of hotspots generated in the chamber is of paramount importance for performance and life-duration issues. Despite this need for fully integrated simulations, typical turbomachinery simulations however often only consider isolated components with either time-averaged constant value, radial profile or least frequently two-dimensional maps imposed at their inlet boundaries preventing any accurate two-way coupling. The objective of this study is to investigate available solutions to perform isolated simulations while taking into account the effect of multicomponent coupling. Investigations presented in the paper focus on the full aero-thermal combustor-turbine interaction research (FACTOR) configuration. The first step of the proposed method is to record conservative variables solved by the large-eddy simulation (LES) code at the interface plane between the chamber and the turbine of a reference simulation. Then, using the spectral proper orthogonal decomposition (SPOD) method, the recorded data is analyzed and can be partially reconstructed using different numbers of frequencies. Using the partial reconstructions, it is then possible to replicate a realistic inlet boundary condition for isolated turbine simulations with both velocity and temperature fluctuations, while reducing the storage cost compared to the initial database. The integrated simulation is then compared to the isolated simulations as well as against simulations making use of averaged quantities with or without synthetic turbulence injection at their inlet. The isolated simulations for which the inlet condition is reconstructed with a large number of frequencies show very good agreement with the fully integrated simulation compared to the typical isolated simulation using average quantities at the inlet. As expected, decreasing the number of frequencies in the reconstructed signal deteriorates the accuracy of the resulting signal compared to the full recorded database. However, isolated simulations with a low number of frequencies still perform better than standard boundary conditions, especially from an aero-thermal point of view.

Evolutionary patterns of cranial ontogeny in Sigmodontines (Rodentia, Cricetidae)

Sigmodontines comprise one of the most diverse radiations of mammals. The cranial ontogeny has been studied in several mammals, but remains poorly studied in the group. We quantified the ontogenetic pattern for 22 sigmodontine species and 8 outgroups, generating partial reconstructions of ancestral allometric growth patterns, and testing the role of evolutionary history on cranial ontogeny. Sigmodontines were conservative in growth pattern, without unique patterns defining tribes. The allometric growth of the cranium was mostly negative, with Akodontini being the most isometric and Phyllotini the most allometric tribes. Allometry of variables associated with the neurocranium was mostly negative, while those linked to trophic functions showed positive allometry or isometry. A general cranial lengthening was detected, but variables associated with cranial width or height grew at lower rates. Cranial growth and development were associated with changes in the musculature functionally involved in bite and mastication. Most changes occurred in earlier postnatal stages, achieving an early morphological optimum. Few changes in the rate of growth at internal nodes were detected, and the stasis along the backbone was recurrent. Cranial elongation was a pattern widespread in the sample and likely a plesiomorphic condition. The few synapomorphies defining the ancestor of Sigmodontinae conform to a pattern with zygomatic arches little expanded laterally and globose braincases. The conservative pattern may be attributed to the biomechanically optimal morphology for omnivorous diets, suggesting that the generalized morphology allows the exploitation of multiple types of food with minor morphological adjustments.

Complete and partial replacement of the inferior vena cava with autologous peritoneum in cancer surgery.

Resection of the inferior vena cava may be required in the courses of oncological surgeries for the tumors originating from or invading it. Management of the remaining defect depends on the extension of the resection. Partial or complete replacement of the inferior vena cava, with a patch or interposition graft, may be required. Standard techniques for the reconstruction with a prosthetic material or the autologous veins can be associated with the prosthetic graft infection, high cost, long-standing anticoagulation, technical difficulties, and/or need for extra incisions. The use of the autologous peritoneum represents an easy and inexpensive alternative for the partial and complete inferior vena cava reconstructions.