Root Geometry Research Articles

Fluid-structure interaction analysis of a healthy aortic valve and its surrounding haemodynamics.

The opening and closing dynamics of the aortic valve (AV) has a strong influence on haemodynamics in the aortic root, and both play a pivotal role in maintaining normal physiological functions of the valve. The aim of this study was to establish a subject-specific fluid-structure interaction (FSI) workflow capable of simulating the motion of a tricuspid healthy valve and the surrounding haemodynamics under physiologically realistic conditions. A subject-specific aortic root was reconstructed from magnetic resonance (MR) images acquired from a healthy volunteer, whilst the valve leaflets were built using a parametric model fitted to the subject-specific aortic root geometry. The material behaviour of the leaflets was described using the isotropic hyperelastic Ogden model, and subject-specific boundary conditions were derived from 4D-flow MR imaging (4D-MRI). Strongly coupled FSI simulations were performed using a finite volume-based boundary conforming method implemented in FlowVision. Our FSI model was able to simulate the opening and closing of the AV throughout the entire cardiac cycle. Comparisons of simulation results with 4D-MRI showed a good agreement in key haemodynamic parameters, with stroke volume differing by 7.5% and the maximum jet velocity differing by less than 1%. Detailed analysis of wall shear stress (WSS) on the leaflets revealed much higher WSS on the ventricular side than the aortic side and different spatial patterns amongst the three leaflets.

Impact of aortic root geometry and degree of aortic calcification on outcomes of patients undergoing TAVI procedure.

Adequate differentiation of calcifications in contrast-enhanced CT scans remains difficult to assess TAVI parameters. The size of the aortic leaflets has not been taken into account so far in present studies. The aim of our study was to establish a new method for optimized quantification of the aortic valve calcification degree in contrast-enhanced CT scans for better preoperative prediction of postoperative paravalvular leak after TAVI. We retrospectively analyzed preoperative contrast-enhanced CT scans of patients who underwent TAVI in our institution between 2014 and 2017. Calcium volume was quantified by a method using contrast enhanced computer tomography (3mensio-Structural Heart-7.2 software) with different iodine contents for better discrimination of contrast agent from calcium and by an individually set Houndsfield Unit (HU) threshold with 50HU above the individually determined reference value. Calcium volume was correlated with surface area of each aortic cusp. Perioperative variables were analyzed. All patients (n = 150) with severe aortic stenosis were treated with TAVI implantation. Overall incidence of postoperative trace to moderate PVL was 37%. The amount of calcium correlated with the incidence of PVL. In a logistic regression analysis total volume of calcification (p = .032) as well as calcification of each aortic cusp (NC_p = .001; RC_p < .001; LC_p = .001) were independent predictors. Calcification degree as well as its correlation with the surface area of each aortic cusp significantly influence incidence of PVL. Our new method improves preoperative quantification of the calcification degree by use of contrast agents with different iodine contents and thereby helps to improve patients' outcomes.

Effects of Root Architecture on Uprooting Properties between Deciduous and Evergreen Species with Different Growth Habits

Roots anchor plants firmly to the soil, enabling them to effectively resist soil erosion and shear failure. Vegetation restoration has been acknowledged as one of the most useful measures for controlling soil loss; however, which root system characteristics were most beneficial for plant anchoring in the soil remains unclear. In the black soil region of northeastern China, which frequently experiences serious soil erosion, pullout tests were carried out on six species of soil and water conservation woody plants with different growth habits (deciduous shrubs, deciduous trees and evergreen trees), and the root geometry and topology of each species were determined. The results showed that the maximum uprooting force and activation displacement (the displacement at the maximum peak in the relationship curve between pulling force and displacement) of shrubs were significantly greater than those of trees, while deciduous trees were significantly greater than evergreen trees. Therefore, the ability of the whole root system to anchor the soil was the largest for shrubs, followed by deciduous trees, and the smallest for evergreen trees. The uprooting force and activation displacement were mainly affected by the root topological index, total root length and the number of inclined roots. The total root length had the greatest influence on the maximum uprooting force, and the root topology had the greatest influence on the activation displacement, both of which can be used as important predictors of plant root anchorage strength. In addition, the plants with the R-type root structure may have a greater ability to anchor the soi, and can be prioritized for vegetation restoration with black soils. These findings provide references and implications for identifying the effective plant strategies for eroded soil restoration in the black soil region of northeastern China and other areas with similar soil types and bioclimates.

Configuration of the neoaortic root after chimney reconstruction in the Norwood procedure.

After staged reconstruction for hypoplastic left heart syndrome, the neoaortic root tends to dilate, and the incidence of significant neoaortic valve insufficiency increases with time. This study aimed to evaluate the mid-term outcomes of the neoaortic root geometries and valve function after chimney reconstruction in the Norwood procedure. Between 2013 and 2021, 20 consecutive patients who underwent chimney reconstruction during the Norwood procedure for hypoplastic left heart syndrome and its variants in our institution were enrolled. The actual diameters of the following points were measured, and Z-scores were calculated based on the normal aortic root geometries using the long axis view of echocardiography at the pre-Norwood stage and the lateral view of angiography at pre-Glenn, pre-Fontan, post-Fontan and follow-up (age 5-6 years) stages: neoaortic valve annulus; sinus of Valsalva; sinotubular junction; and ascending aorta just proximal to the anastomosis to the aortic arch. The degree of neoaortic valve regurgitation was evaluated by echocardiography at each stage. The median follow-up period was 3.9 years. Neoaortic roots after chimney reconstruction were spared from progressive dilation over time. With growth, the conical configuration of the neoaortic roots was preserved without geometrical distortion. The Z-scores of the annulus, sinus of Valsalva, sinotubular junction and ascending aorta ranged roughly from 4 to 6, 4 to 6, 2 to 4 and 0 to 2, respectively. All neoaortic valves at each stage had mild or no regurgitation. Chimney reconstruction prevented neoaortic root dilation and avoided significant neoaortic valve regurgitation in the mid-term. These neoaortic dimensions with smooth flow profiles in the neoaorta after chimney reconstruction may have contributed to the current results. Further studies are needed to clarify the long-term outcomes.

Florida sleeve procedure for type II aortic regurgitation with aortic root enlargement: a case report

Abstract Background Florida sleeve procedure is an operative technique for aortic root reconstruction that offers advantages such as reduced bleeding risk, shorter operation time, and improved formation of the atrioventricular junction (AVJ) and sinotubular junction (STJ). In our department, we perform a Florida sleeve procedure for aortic regurgitation (AR) associated with aortic root enlargement of less than 40 mm in diameter of the Valsalva sinus. Here, we present a case of severe type II AR with aortic root enlargement where we successfully performed Florida sleeve procedure and augmented it with autologous pericardium. Case presentation A 62-year-old male patient was referred for cardiovascular surgery after a transthoracic echocardiogram indicated left ventricular enlargement and severe AR. Preoperative multidetector computed tomography (MDCT) revealed AVJ of 28.2 mm, Valsalva sinus of 38.4 mm, STJ of 36.1 mm, and ascending aorta of 40.1 mm, indicating enlargement from the aortic root to ascending aorta. Preoperative transesophageal echocardiography (TEE) revealed that the main cause of AR was suspected to be the right coronary cusp prolapse (RCC). Intraoperative findings showed that the tricuspid aortic valve had no limitation of motion, but the RCC was subjected to central bending and prolapsed. The leaflet bend was thickened and shortened causing AR (type II). The geometric height (gH) of RCC was short at 14 mm, while the other valve cusps were 20 mm. An augmentation of RCC was performed using autologous pericardium, followed by a Florida sleeve procedure performed using 26-mm Gelweave Valsalva™ grafts. The gH of RCC after augmentation was 23 mm, and the effective height was adjusted to 10 mm by central plication, showing no AR by TEE. Postoperative MDCT revealed AVJ of 22.2 mm, Valsalva sinus of 30.9 mm, and STJ of 21.9 mm. Therefore, the Florida sleeve procedure provided a reduction that preserved the geometry of the aortic root, including AVJ and STJ, as intended. Conclusions Florida sleeve procedure is a reliable and simple method for ensuring uniform aortic root geometry. A favorable outcome was obtained using the Florida sleeve procedure and augmentation with autologous pericardium in a patient with type II AR and aortic root enlargement.

A Cone Beam Computed Tomographic Evaluation of Root Canal Variations in Primary Mandibular Second Molars and Permanent Mandibular First Molars in Indian Population - A Retrospective Study

Background Primary teeth in some instances can have peculiar internal root and canal geometry including interconnections involving furcation with horizontal anastomoses which makes endodontic management extremely challenging. Being one of the first permanent teeth to erupt the mandibular first permanent molars MFPMs are frequently afflicted by caries neccessitating endodontic management.Aim The study aimed to determine the variations in the morphology of the root canals of primary mandibular second molars PMSMs and MFPMs and also the usefulness of Cone Beam Computerized Tomography CBCT in determining the root canal morphology. Methods Fifty CBCT images of children aged 5-10 years were obtained from the institutional database. Hundred PMSMs and MFPMs each were analyzed for a variety of factors including the number of roots and root canals and their form.Results Most of the PMSMs and MFPMs n96 had two distinct roots and the remaining four had three roots. In the distal root one root and two root canals were recognized in 62 cases one root and a single canal in 34 and two roots and a single canal in each of the remaining 4 cases. In the mesial root two root canals were detected in 96 cases and a single canal was noted in 4 of cases. Moreover 72 of the MFPM specimens had three root canals 20 had four and 8 had just two canals.Conclusion This study showed that different root canal configurations can be found in PMSMs and MFPMs. Therefore these variations should be considered during the management.

Altered blood flow due to larger aortic diameters in patients with transcatheter heart valve thrombosis.

The etiology of transcatheter heart valve thrombosis (THVT) and the relevance of the aortic root geometry on the occurrence of THVT are largely unknown. The first aim of this pilot study is to identify differences in aortic root geometry between THVT patients and patients without THVT after transcatheter aortic valve implantation (TAVI). Second, we aim to investigate how the observed difference in aortic diameters affects the aortic flow using idealized computational geometric models. Aortic dimension was assessed using pre-TAVI multi-detector computed tomography scans of eight patients with clinical apparent THVT and 16 unaffected patients (two for each THVT patient with same valve type and size) from the Bern-TAVI registry. Among patients with THVT the right coronary artery height was lower (-40%), and sinotubular junction (STJ) and ascending aorta (AAo) diameters tended to be larger (9% and 14%, respectively) compared to the unaffected patients. Fluid-structure interaction (FSI) in two idealized aortic models with the observed differences in STJ and AAo diameter showed higher backflow rate at the STJ (+16%), lower velocity magnitudes in the sinus (-5%), and higher systolic turbulent dissipation rate in the AAo (+8%) in the model with larger STJ and AAo diameters. This pilot study suggests a direct effect of the aortic dimensions on clinically apparent THVT. The FSI study indicates that larger STJ and AAo diameters potentially favor thrombus formation by increased backflow rate and reduced wash-out efficiency of the sinus. The reported observations require clinical validation but could potentially help identifying patients at risk for THVT.

Numerical investigation of calcification effects on aortic valve motions and ambient flow characteristics

The pathogenesis and progression of calcific aortic stenosis pose a significant challenge in medical science due to the intricate nature of blood fluid dynamics. To better understand this crucial phenomenon, this study investigates the physiological behaviors of aortic valves with varying degrees of lesions and ambient flow conditions using an in-house CFD solver, CgLES-Y code. The code is validated by simulating two-dimensional valve opening and closure, followed by the extension to three-dimensional symmetrically simplified valve dynamics. The simulation results exhibit great agreement with other numerical, experimental and clinical data. Patient-specific models of the aortic root and inner valve geometries are developed based on CT images. Analysis of fluid dynamics traits, configuration properties and leaflet stress is performed for both normal and calcified aortic valves during the systolic and diastolic periods. The study further examines the impact of calcium deposition on abnormal flow fields and leaflet motion, which indicates that calcium deposition increases the tensional burden on healthy leaflets, therefore, the microcosmic increase in valve modulus leads to global damage extending from the root to the tip, whereas macroscopic calcification primarily induces damage in the vicinity of the calcium compound. Additionally, the generation of additional vortices on the valve surface and sinus lumen heightens the likelihood of calcium accumulation.

Association between invasively measured central aortic pulse pressure and diameter of ascending aorta

Data on the relationship between arterial pulsatile hemodynamics and aortic root geometry, using invasive hemodynamic measurement, has been scarce. Thus, this study aimed to assess the relationship between invasively measured aortic pulse pressure (aPP) and the diameter of ascending aorta (AoD). We analyzed 665 subjects (64.3 ± 11.0 years; 34.6% female) who underwent elective invasive coronary angiography (ICA) for the evaluation of coronary artery disease. Transthoracic echocardiography was performed on the same day, and AoD was measured at the level of 1 cm above the sinotubular junction at the end-diastole. Body surface area (BSA)-adjusted AoD (AoD/BSA) was used for the analysis. A pig-tail catheter was used to measure aortic pressures at a level approximately 3 cm above the aortic valve just before ICA. aPP was calculated as the difference between systolic and diastolic pressures of the aorta. In multiple linear regression analyses, aPP (β = 0.259; P < 0.001) was found to be significantly correlated with AoD/BSA even after controlling for potential confounders. This correlation power was stronger than aortic systolic pressure (β = 0.189; P < 0.001) and brachial pulse pressure (β = 0.091; P = 0.018) at the same multivariable analyses. In conclusion, our study demonstrated a significant association between invasively measured aPP and AoD/BSA, providing stronger evidence for the link between central aortic pulsatile hemodynamics and aortic root geometry.

Evaluation of the anatomic sinus after transcatheter aortic valve replacement

Abstract Background Transcatheter aortic valve replacement (TAVR) determines the creation of outer area between the cage and the aortic wall named the ‘anatomic sinus’ (Figure 1 A-B). This newly formed space of the sinuses of Valsalva (SOV) might disrupt the physiological currents of Valsalva and contribute to the formation of subclinical leaflets thrombosis (SLT). The evaluation of the root geometry after TAVR is generally performed with multi detector computer tomography (MDCT), and the role of transthoracic echocardiography (TTE) needs further validation. Purpose The aim of this study was to test reproducibility of 2D TTE assessment of the anatomic sinus dimension with MDCT as reference. We also investigated predictors for SLT. Methods We enrolled 90 patients who underwent TAVR with self-expandable prosthesis. 2D TTE was performed using Philips EPIQ-7, and echocardiograms analysed offline with Philips QLAB cardiac analysis. Both SOV and prosthesis diameters were assessed in long and short-axis parasternal view (PLAX / PSAX) and the bidimensional area of the anatomic sinus was calculated (Figure 2 A-B). Inter-observer (observer 1 – 2) reproducibility was assessed by the means of interclass correlation coefficient (ICC). MDCT was performed in 50 individuals to evaluate concordance (Bland Altman test) with the 2D TTE anatomic sinus area and also to detect SLT (Figure 2 C-D). Multivariable model was built to assess predictors of SLT. Results Mean follow-up was 13.1 months. There was excellent and good correlation with regard to the diameter of the SOV and the prosthesis measured in PLAX view by observer 1 and 2: ICC: 0.93, 95% Confidence Interval (CI) (0.76–0.97), p&amp;lt; 0.001; ICC: 0.87(0.63,0.96), p&amp;lt;0.001, SOV and prosthesis respectively. The correlation found with regard to the diameter of the SOV and the prosthesis measured in PSAX view was also excellent ICC: 0.90(0.68,0.97), p=0.001; and good ICC: 0.88(0.63,0.96), p &amp;lt;0.001, SOV and prosthesis respectively. The anatomic sinus areas assessed by 2D TTE were similar compared to areas derived by MDCT (4.1 ± 1.09 cm2 vs. 4.02 ± 1.55 cm2, respectively, p=0.57). Bland–Altman analysis of anatomic sinus area measured on 2D TTE and MDCT respectively, indicated high level of agreement and no fixed or proportional bias. Native bicuspid valve, but not the anatomic sinus area, was the only independent predictors for SLT. Conclusions Following TAVR, the newly formed anatomic sinus could be assessed with good reproducibility with 2D TTE. We found a significant association between native bicuspid valve and SLT diagnosed with MDCT.Figure 1A-BFigure 2A-D

Evaluation of the anatomic sinus after transcatheter aortic valve replacement

BackgroundFollowing transcatheter aortic valve replacement (TAVI), the newly formed ‘anatomic sinus’.may contribute to the formation of subclinical leaflet thrombosis (SLT).The evaluation of root geometry after TAVI is generally performed using multi-detector computed tomography (MDCT), and the role of transthoracic echocardiography (2D TTE) requires further validation. Thus, we aimed to test the reproducibility of 2D TTE assessment of the anatomic sinus with MDCT as a reference and its association with SLT. Methods2D TTE was performed in 90 patients, and the echocardiograms were analyzed offline. Both sinus of Valsalva (SOV) and prosthesis diameters were assessed in the long- and short-axis parasternal views (PLAX/PSAX), and the anatomic sinus area was calculated. Inter- and intra-observer reproducibility were assessed using the interclass correlation coefficient (ICC). MDCT was performed in 50 individuals to evaluate concordance with 2D TTE and to detect SLT. ResultsThere was excellent correlation regarding the diameter of the SOV and the prosthesis in PLAX (ICC: 0.93 (95% CI: 0.76,0.97); ICC: 0.80 (95% CI: 0.63,0.96)) and PSAX view (ICC: 0.90 (95% CI: 0.68,0.97); ICC: 0.88 (95% CI: 0.63,0.96)). Bland–Altman analysis of 2D TTE and MDCT anatomic sinus areas indicated a high level of agreement. SLT was detected in 8 individuals (16%); 3 patients had severe SLT at the level of 1 cusp. Conclusions2D TTE might play a role in the evaluation of the anatomic sinus after TAVI. The importance of this space and its effects on the SLT remain uncertain.

Positional trueness of three removable die designs with different root geometries manufactured using stereolithographic 3D printing

Statement of problemThree-dimensional (3D) printed casts are a suitable alternative to dental stone casts. Contemporary dental design computer programs permit designing definitive casts with removable dies with different root geometries and retention mechanisms. Studies on the positional trueness of 3D-printed removable dies with different root geometries are lacking. PurposeThe purpose of this in vitro study was to investigate the 3D displacements of three 3D-printed removable die designs with different root geometries. Material and methodsThe digital file of a dental stone alveolar cast with root-form removable dies (MOD UJ IV Fixed Prosthetics; Ivoclar AG) was used as a reference to create 3 removable die and alveolar cast designs (Root Form, RF; Conical, CON; Cylindric, CYL) with different root geometries in 2 dental design computer programs (DentalCAD 3.1 Rijeka; exocad; GmbH; InLab CAD 22.0; Dentsply Sirona). 3 equidistant Ø1-mm spheres (C, Cervical; M, Middle; O, Occlusal) were designed on the buccal surface of the coronal portion of the removable die to evaluate their displacement. A total of 45 alveolar casts with 45 removable dies were fabricated using a stereolithographic 3D printer (Form 3; Formlabs); each die group consisted of 15 specimens. After fabrication and postprocessing, the specimens were scanned, and their digital files were analyzed in a metrology-grade computer program to evaluate the displacement of the removable dies with respect to the position of the die in the master reference file. Subsequently, the data were analyzed using a 3-way analysis of variance (ANOVA) followed by step-down Bonferroni-corrected pairwise comparisons (α=.05). ResultsTwo statistically significant 2-way interactions were detected between the independent variables, die design and direction (P<.001), and location and direction (P<.001). The post hoc analysis identified significant differences between the displacement values of RF and CYL (P<.001) and RF and the CON (P<.001) designs on the Y axis. The measured displacements were statistically different between the C and O locations on the Y axis (P=.001) and the M and O locations on the Z axis (P=.006). ConclusionsThe root geometry of a 3D-printed removable die and alveolar cast can affect seating, and variable degrees of tipping of the removable die can be seen. The seating and congruence of the removable die with the interocclusal space and relationships observed intraorally should be confirmed before adjusting indirect restorations.

On inclusions of exceptional long root geometries of type E

On inclusions of exceptional long root geometries of type E

A unimodal sequence with mode at a quarter length

ABSTRACT We show that the number of partitions with m even parts and largest hook length n is strongly unimodal with mode for . We establish this result by induction, using a 5-term recurrence due to Lin, Xiong and Yan, and two 4-term recurrences obtained by Zeilberger's algorithm. The sequence is not log-concave. Using Möbius transformation and the method of interlacing zeros, we obtain that every zero of every generating polynomial lies on the left half part of the circle . Moreover, as an application of Wang and Zhang's characterization of root geometry of polynomial sequences that satisfy a recurrence, we confirm that the zeros are densely distributed on the half circle.

An experimental study on root-reinforced soil strength via a steel root analogue in unsaturated silty soil

AbstractLandslides due to catastrophic weather events, especially heavy rainfall, have risen significantly over the last several decades, causing significant damage and affecting the health and livelihoods of millions of people. Using tree roots to bio-engineer shallow slopes has been proven to be a cost-effective, sustainable measure and thus has gained increasing popularity. As slope failure often occurs under heavy precipitation, it is important to understand the mechanical interactions in the soil matrix surrounding a root to better estimate the reinforcement capacity of a root system, especially as the soil undergoes wetting from drier conditions. However, very few studies of root reinforcements have considered the effects of degree of saturation on behaviour. In this study, steel wires are used as a root analogue to explore the impact of root geometry, soil dilation and soil saturation on the pull-out behaviour of a root and three commonly used unsaturated soil strength models have been used to interpret the pull-out results. It was found that roots with larger diameter did not contribute to additional resistance. Also, a linear relationship between degree of saturation and pull-out strength was identified over a large range of suctions and one of the unsaturated soil strength models seemed to provide a more reasonable interpretation. The results will help future bioengineering slope design by improving the understanding of soil-root interface behaviour, including the effect of root diameter in slippage failure and greater emphasis on the importance of taking degree of saturation into account in unsaturated soil strength models.

Aortic root geometry following composite valve graft implantation: Implications for future valve-in-valve procedures

ObjectivesBiological composite valve grafts (CVGs) are being performed more frequently, which increases the need for interventions treating bioprosthetic valve failure. The feasibility of valve-in-valve procedures in this population is uncertain. This study aimed to assess changes in aortic root geometry and coronary height following CVG implantation to better understand future interventions. MethodsWe retrospectively identified 64 patients following bioprosthetic CVG replacement with pre- and postoperative computed tomography angiography. Root assessment was conducted as in preprocedural transcatheter aortic valve evaluation using a virtual valve simulation. ResultsIn 64 patients (age, 67.6 ± 9.3 years; 76.6% men) the preoperative coronary height was 14.3 ± 6.8 mm for the left coronary artery (LCA) and 17.9 ± 5.9 mm for the right coronary artery (RCA), which significantly decreased after CVG implantation, with 8.7 ± 4.4 mm for the LCA and 11.3 ± 4.4 mm for the RCA (P < .001). The virtual valve-to-coronary distances measured 4.0 ± 1.3 mm (LCA) and 4.6 ± 1.4 mm (RCA). Overall, 59.4% (n = 38) of patients with bio-CVGs would have been at risk for coronary obstruction, 29.7% (n = 19) for LCA, 10.9% (n = 7) for RCA, and 18.8% (n = 12) for combined LCA and RCA. ConclusionsCoronary height significantly decreased following CVG implantation. The majority of patients after bio-CVG were at a potential risk for coronary obstruction in future valve-in-valve procedures. Further studies are needed to identify the best possible technique for coronary reimplantation and other measures to diminish the risk for future coronary obstruction in this population.

Numerical Modelling Techniques for Stability Analysis of Slopes Reinforced with Shallow Roots

It is well recognised that plant vegetation and roots are capable of improving the shear strength of hillslopes by reinforcing soil shear resistance. Several key factors influencing the level of slope reinforcement include root geometry, orientation and strength. To assess the mechanical performance of vegetated slopes using numerical methods, root structures can be represented by beam and pile elements to mirror root behaviour. In contrast, root reinforcement can be modelled indirectly through a root cohesion factor, supplying additional strength to the soil surrounding the root zone. In this paper, correlations between these two numerical methods are presented, highlighting the applicability of each technique based on various root characteristics. Three types of root geometries are presented, consisting of a primary tap root, a secondary cohesion zone surrounding the main root and a root branching process. The results of the finite element analysis demonstrate the variation in the slope factor of safety for both methods, with a set of correlations between the two modelling approaches. A series of stability charts are presented for each method, quantifying the effects of root characteristics on slope reinforcement.

Association between the sinus of Valsalva height and biometric parameters in patients with Marfan syndrome associated with aortic root aneurysm

Patients with Marfan syndrome and aortic root aneurysm require pre-surgical analysis of aortic root geometry for aortic reconstruction. The aim of this study is to perform the morphometric analysis of the sinus of Valsalva height and correlation between the former, age, weight, height, body mass index (BMI), and body surface area (BSA) in patients with Marfan syndrome and aortic root aneurysm. Data from 34 patients (28 men, 6 women) with Marfan syndrome and an ascending aortic diameter exceeding 45 cm were obtained using computed tomography angiography. Gender-based differences were observed in the height of the left aortic sinus – by 47.23% (36.47±12.48 mm in men against 24.77±4.26 mm in women, р=0.0003). In men, a strong direct correlation has been identified between height and the right aortic sinus height (r=+0.75, р&lt;0.0001), the posterior aortic sinus height (r=+0.71, р&lt;0.0001), and the left aortic sinus height (r=+0.75, р&lt;0.0001). Moderate reverse correlation has been discovered between the sinus of Valsalva height and BMI. No correlations have been identified between weight, BSA and the sinus of Valsalva height (р&gt;0.05). In women, a strong direct correlation (Pearson) has been identified between age and the right aortic sinus height (r=+0.84, p=0.04), between weight and the left aortic sinus (r=+0.73, p=0.04) and between BSA and the left aortic sinus (r=+0.73, р=0.04). Aortic sinus height in men increases with height and decreases with higher BMI and age. Weight and BSA do not affect the sinus of Valsalva height. In women, the sinus of Valsalva height is impacted by age, weight and BSA.

An integrated geophysical and geological 3D model to characterize the feeder system of La Joya Honda and La Joyuela maars complex in central Mexico

La Joya Honda maar is recognized as one of the largest maar craters of the world (∼1200 m x 930 m), and La Joyuela maar, with axes of ∼1160 m x ∼790 m, is located in San Luis Potosí, México. Geophysical characterization using terrestrial magnetometry, aeromagnetic data, satellital gravimetry, and petrographic analysis of rock samples were interpreted jointly to improve the knowledge of both maars, their structural root geometry, and dimension maar-diatreme volcanoes. Magnetic and gravimetric analysis of both maars exhibit high magnetic anomaly values (≥400 nT) related to low gravimetric signatures (-5.2 to 1.5 mGal) and show characteristic geophysical maar behavior, complemented by positive anomalies (0.137 nT/m and 0.019 mGal/m, respectively) in the Analytic Signal result. Additionally, associated with the diverse tectonic and faulting events that the area has been subjected to, lineaments analysis and rose diagrams were used to determine structural tendencies, indicating the regional stress field (NNW trending) related to local fault orientations (E-W, NE-SW), which might be expected for the formation of maars with a comparable fracturing disposition at a depth between La Joya Honda and La Joyuela maars. This investigation shows the first magnetic inversion model in the zone, identified two vertical conduits susceptibility isosurface (2.53x10-4 SI) with an exceeded depth of -12 km below both volcanic structures, where regional analysis of lineaments and Werner solutions determine weak cortical structures. Furthermore, the petrological evidence (xenoliths) supports the geophysical model, which helps to understand regional factors that make the ideal environmental conditions for maar formation. Our new results contribute to the knowledge of the feeder system of the maars complex found in La Joya Honda and La Joyuela maars, demonstrate that the combination of different regional structural and local trends controls the magmatic evolution producing preferential paths for magma ascent.

Geometric distribution characteristics and mechanical reinforcement effect of herbaceous plant roots at different growth periods

The growth form of herbaceous plant roots and their mechanical reinforcement effect on soil play a positive role in preventing soil erosion. Herbaceous plant roots grow with increasing growth periods, thus resulting in different root geometry and mechanical reinforcement in different growth periods. To explore the difference in root system characteristics of herbaceous plants and their effect on soil reinforcement in different growth periods, two herbaceous plants, Chenopodium album, and Setaria viridis, were taken as the research objects. First, the diameters of the two herbaceous plant roots in each growth period were measured by pixel conversion, and then the root area ratio (RAR) was calculated, and the tensile force of the roots in each growth period was measured with a tensile force meter. The measurement results were substituted into the Wu-Waldron model (WWM), and the WWM was corrected by the direct shear test. The modified WWM was used to calculate the mechanical reinforcement effect of roots at different growth periods. Second, the average root area ratio (ARAR) and the average root additional cohesion (Acr) in different growth periods of the two herbaceous plants were calculated. Finally, to characterize the reinforcement effect of herbaceous plant roots in different growth periods, FLAC3D was used to simulate the compressive strength of the root-soil composite in the unconfined compressive state. The results showed that the RAR of Chenopodium album and Setaria viridis increased with the increase of the growth period, and the standard deviation of RAR after 78d was higher than that in the previous period. The root tensile force of Chenopodium album on 14d and Setaria viridis on 21d was the smallest, and the tensile force of roots increased significantly after continued growth for 7d, and the effect of further growth was not obvious. The root additional cohesion of Chenopodium album and Setaria viridis fluctuated with increasing growth periods. The ARAR and Acr of Chenopodium album and Setaria viridis increased with the increase of the growth period and showed a significant positive correlation (p < 0.01). With the increase in the growth period, the compressive strength of the root-soil composite increased linearly. When the herbaceous plant grew to 131d, the compressive strength of the root-soil composite of Chenopodium album and Setaria viridis increased by 24% and 21% compared with that of the rootless soil. This study can provide a reference for the study of using the mechanical reinforcement of herbaceous plant roots to inhibit soil erosion.