Axial Segments Research Articles

Performance evaluation for the domain decomposition method in nonlinear vibration of the composite hard-coating cylindrical shell.

The applications of the modified domain decomposition method in nonlinear vibration analysis of the composite hard-coating cylindrical shells are still at a relatively superficial level, owing to the fact that its performance under different decomposition parameters has not been thoroughly investigated for achieving sufficient precision. A parametric domain decomposition method is developed to facilitate self-performance evaluation in nonlinear vibration analysis of the shell. Correspondingly, in order to avoid a mass of redundant computation of the segment stiffness and material damping matrices during iterations, a specialized preprocessing scheme is designed by pre-establishing the parametric analytical expressions and matrix databases. The resonant response is sensitive to the circumferential segment number, but weakly affected by the axial segment number. The optimum circumferential segment number in the present study is suggested to be Nθ = 70, which can achieve good calculation accuracy and efficiency. Highly consistency is shown for the distributions of axial equivalent strain under different axial segment numbers. Smaller circumferential segment numbers would result in larger equivalent strain and bad solution accuracy. The sufficient solution accuracy of nonlinear vibration of the composite hard-coating cylindrical shell can't be achieved by increasing the axial segment number with constant segment width, but only by enough circumferential segment number, which is fundamentally determined by its equivalent strain distributions and gradients, and is with close relation to the axial and circumferential wave numbers of the shell.

Kinematics of the axial segment of horses submitted to dynamic mobilization exercises

This study aimed to investigate the kinematic effects of dynamic mobilization exercises on the axial segment in horses. Twelve horses crossbreed were used, which were monitored before (day 0) and at the end of the experimental period (day 120), distributed in an entirely randomized design, totalizing six repetitions per treatment The treatments consisted of two experimental groups, one composed of horses not performing the dynamic mobilization exercises and the other composed of horses submitted to the mobilization program. The static kinematic variables were evaluated, by means of hemispherical markers such as depth (cm), angle (°), difference in depth and angle, for each vertebral level analyzed (T10, T13, T17, L1 and L3), as well as total range of motion for depth and angle, in which this parameter expressed the thoracolumbar motion in its entirety. The performance of dynamic mobilization produced a significant (P<0.05) decrease in thoracolumbar depth and increase in thoracolumbar flexion angle, compared to the group that did not perform the functional exercises. A reduction in the total thoracolumbar depth of -6.28 cm (P<0.0001) was observed in horses that underwent the exercises. The same response behavior was verified for angular measurement, in which there was an increase in the total ROM of the angle, reflecting thoracolumbar flexion, of 15.54°(P<0.00001). It was concluded that dynamic mobilization exercises consistently produce flexion of the axial segment, becoming a potential tool to improve range of motion and thoracolumbar function in horses.

Axial Attention Convolutional Neural Network for Brain Tumor Segmentation with Multi-Modality MRI Scans.

Accurately identifying tumors from MRI scans is of the utmost importance for clinical diagnostics and when making plans regarding brain tumor treatment. However, manual segmentation is a challenging and time-consuming process in practice and exhibits a high degree of variability between doctors. Therefore, an axial attention brain tumor segmentation network was established in this paper, automatically segmenting tumor subregions from multi-modality MRIs. The axial attention mechanism was employed to capture richer semantic information, which makes it easier for models to provide local-global contextual information by incorporating local and global feature representations while simplifying the computational complexity. The deep supervision mechanism is employed to avoid vanishing gradients and guide the AABTS-Net to generate better feature representations. The hybrid loss is employed in the model to handle the class imbalance of the dataset. Furthermore, we conduct comprehensive experiments on the BraTS 2019 and 2020 datasets. The proposed AABTS-Net shows greater robustness and accuracy, which signifies that the model can be employed in clinical practice and provides a new avenue for medical image segmentation systems.

Timing of Vertical Head, Withers and Pelvis Movements Relative to the Footfalls in Different Equine Gaits and Breeds.

Knowledge of vertical motion patterns of the axial body segments is a prerequisite for the development of algorithms used in automated detection of lameness. To date, the focus has been on the trot. This study investigates the temporal synchronization between vertical motion of the axial body segments with limb kinematic events in walk and trot across three popular types of sport horses (19 Warmbloods, 23 Iberians, 26 Icelandics) that are known to have different stride kinematics, and it presents novel data describing vertical motion of the axial body segments in tölting and pacing Icelandic horses. Inertial measurement unit sensors recorded limb kinematics, vertical motion of the axial body at all symmetrical gaits that the horse could perform (walk, trot, tölt, pace). Limb kinematics, vertical range of motion and lowest/highest positions of the head, withers and pelvis were calculated. For all gaits except walk and pace, lowest/highest positions of the pelvis and withers were found to be closely related temporally to midstance and start of suspension of the hind/fore quarter, respectively. There were differences in pelvic/withers range of motion between all breeds where the Icelandic horses showed the smallest motion, which may explain why lameness evaluation in this breed is challenging.

A novel dynamic modeling method of defective four-row roller bearings considering the spatial contact correlation between the roller and defect zone

Dynamic modeling is an effective method of researching dynamic characteristics of the four-row roller bearing (FRRB) containing localized defects. A novel dynamic modeling method considering the spatial contact correlation between the roller and defect zone is proposed to investigate the dynamic changes of contact force, displacement as well as vibration response as the roller passes through the defect zone. The interaction form is classified based on the spatial dimension correlation between the roller and defect zone. Contact force, displacement and vibration response are compared according to the variation of defect size. The analysis results indicate that the dynamic responses of defective FRRB are closely related to the defect zone width and depth on the axial segment and the length of the radial section. Magnitude and time interval of the multi-impulse are related to the roll's radial load and the rotational speed. The simulated outcomes closely match the results of the experiment.

Simulating self-powered neutron detector responses to infer burnup-induced power distribution perturbations in next-generation light water reactors

Understanding how 3D power distribution will be monitored throughout reactor core volumetric space in next-generation nuclear power reactors is crucial to the design, deployment, and licensing of these reactors. Although numerous techniques exist for 3D power distribution monitoring based on the response of both in situ and ex situ sensors currently implemented or proposed for use in the US reactor fleet, crucial details about these techniques are often unclear. The publicly available documentation does not include information such as how well these techniques are characterized and optimized in their implementations and the levels of uncertainty in the inferred 3D power distribution. The work described herein investigated a recently developed 3D power distribution inferencing method as applied to two next-generation reactor simulations: (1) the NuScale small modular reactor design and (2) the Westinghouse AP1000 design, both of which contain in-core strings of vanadium self-powered neutron detectors (SPNDs). This investigation considered a range of SPND string sensor densities, as well as a range of 3D power distribution axial segment sizes. SPND response simulation is informed by neutron flux calculations in representative homogenized cores. For the different sensor densities and power distribution axial segment sizes in these simulations, the average solution error, solver iterations, and run time were tracked to parameterize the sensor-core configuration.

The Omnitrap Platform: A Versatile Segmented Linear Ion Trap for Multidimensional Multiple-Stage Tandem Mass Spectrometry.

Multidimensional multiple-stage tandem processing of ions is demonstrated successfully in a novel segmented linear ion trap. The enhanced performance is enabled by incorporating the entire range of ion activation methods into a single platform in a highly dynamic fashion. The ion activation network comprises external injection of reagent ions, radical neutral species, photons, electrons, and collisions with neutrals. Axial segmentation of the two-dimensional trapping field provides access to a unique functionality landscape through a system of purpose-designed regions for processing ions with maximum flexibility. Design aspects of the segmented linear ion trap, termed the Omnitrap platform, are highlighted, and motion of ions trapped by rectangular waveforms is investigated experimentally by mapping the stability diagram, tracing secular frequencies, and exploring different isolation techniques. All fragmentation methods incorporated in the Omnitrap platform involving radical chemistry are shown to provide complete sequence coverage for partially unfolded ubiquitin. Three-stage (MS3) tandem mass spectrometry experiments combining collision-induced dissociation of radical ions produced by electron meta-ionization and further involving two intermediate steps of ion isolation and accumulation are performed with high efficiency, producing information rich spectra with signal-to-noise levels comparable to those obtained in a two-stage (MS2) experiment. The advanced capabilities of the Omnitrap platform to provide in-depth top-down MSn characterization of proteins are portrayed. Performance is further enhanced by connecting the Omnitrap platform to an Orbitrap mass analyzer, while successful integration with time-of-flight analyzers has already been demonstrated.

Fast Current Distribution Simulation Method for No-Insulation HTS Coil With Defects

This paper presents a numerical method for fast simulation of current distribution in a no-insulation (NI) high temperature superconductor (HTS) coil with defects. A refined distributed-circuit model based on the partial element equivalent circuit (PEEC) approach is adopted to calculate the transient current distribution due to screening current. To reduce the time required for the simulation, a nonuniform axial segmentation method is presented in which the outer axially-subdivided azimuthal element is narrower than the inner element. In order to verify the simulation method, three NI HTS single-pancake coils are considered with the following characteristics: 1) the coil without any defects; 2) with one defect; 3) with two defects. The simulation results of current distribution due to screening current, total azimuthal current, radial current, and central magnetic field are presented. Moreover, it is proved that the time required for the simulation can be reduced by the nonuniform axial segmentation method without significant discrepancies in results.

Accuracy Of A Portable Motion Capture System For Kinematic Analysis Of Movement Skills In Children

PURPOSE: With recent advances in motion capture technology, there remains to be an accessible field-based measurement system for kinematic analysis in physical education. The purpose of this research is to assess the accuracy of a portable, cost-effective motion capture system to assess movement skills in children. METHODS: Eighteen healthy children ages 5-17 years performed the vertical jump and land (JL) and leap while being recorded by the Microsoft Kinect V2 with AssessLink software and Vicon MX13 with Nexus 2.0. Data was analyzed using Pearson correlation coefficient and a Bland-Altman plot to determine accuracy of the Kinect V2 to collect kinematic data for nine body segments during five phases of the JL and eight body segments during three phases of a leap. RESULTS: Overall, the correlation and mean bias between the two devices varied by body segment, movement type, and movement phase. For JL, the Pearson r for knees and shoulder ranged from -.239 (p = .109) to .521 (p < .001) and -.743 (p < .001) to .410 (p < .05), respectively. For JL, bias and level of agreement showed better agreement in the spine, hips, and knees. Sagittal assessment of leap often produced results for the appendicular skeleton that did not appear valid. Pearson r for axial segments including the sagittal spine ranged from .345 (p = .032) to .553 (p < .001) across the three movement phases. CONCLUSIONS: With limited measurements that are considered acceptable, our results indicate the Kinect V2 with AssessLink should not be used as a replacement for laboratory-based kinematic assessment. If used, the intrinsic limitations of the Kinect V2 promote a necessity to be selective of body segments, movement skills, and phases to be quantitatively assessed.

MBE-Grown Hybrid Axial Core–Shell n-i-p GaAsSb Heterojunction Ensemble Nanowire-Based Near-Infrared Photodetectors up to 1.5 μm

In this paper, high-performance self-assisted molecular beam epitaxy (MBE)-grown conventional core–shell (C–S) n-i-p GaAsSb nanowires (NWs) and a novel hybrid axial C–S n-i-p GaAsSb ensemble NW-based near-infrared photodetector (NIRPD) on nonpatterned Si substrate are demonstrated. The conventional room-temperature (RT) C–S n-i-p GaAsSb NW with a high responsivity of 190 A/W and a higher detectivity of 1.1 × 1014 Jones at −1 V bias and wavelength of 1.1 μm is reported by optimizing the intrinsic region thickness and appropriately compensating the intrinsic p-type behavior with n-dopant Te. Furthermore, hybrid axial C–S n-i-p GaAsSb has been band-gap-engineered for wavelength up to 1.5 μm, exhibiting responsivity of 18 A/W and detectivity of 1.1 × 1013 Jones operating at RT. In this hybrid design, we have combined both axial and radial intrinsic (i-) segments of different Sb% compositions to enhance the photoabsorption in the NIR region; hence, the photogenerated current and also the high-band-gap axial i-region help to suppress the trap-assisted tunneling mechanism, which is found to be advantageous over conventional C–S NW architectures. In addition, high rectification ratio from current–voltage (I–V) measurements, suppression of low-frequency noise, lack of 1/f noise, a low corner frequency of ∼2.5 Hz beyond which there is the presence of only frequency-independent white noise from low-frequency noise (LFN) measurements, and bias- and frequency-dependent capacitance–voltage (C–V) measurements suggest the formation of a high-quality C–S junction in the hybrid structure. Thus, our findings reveal that the hybrid axial C–S NW architecture provides the flexibility of three-dimensional (3D) design, which offers an unprecedented prospect for expanding IRPD and other next-generation optoelectronic device applications.

Transition to magma-driven rifting in the South Turkana Basin, Kenya: Part 1

Characterization of the role of magma in driving rift basin evolution is fundamental to our understanding of how extensional plate boundaries develop. Here, we examine patterns of normal faulting, volcanism and magmatism in the South Turkana Basin, Kenya, to test how magmatism has impacted the Quaternary evolution of this system. Utilizing high-resolution, single-channel reflection seismic data and radiocarbon-dated cores, we estimate that shallow Holocene normal faulting accounts for 3.5–5.8 mm a −1 of extension, consistent with estimates farther south in the Suguta Basin. Spatial fault patterns show that extension in the Holocene is concentrated along a c. 20 km wide intra-rift fault network, aligning with the axial volcano, South Island. We suggest that up to 85% of Late Quaternary regional extension is accommodated within an axial magmatic segment rather than on the border fault system responsible for the original basin architecture. Axial extension increases towards South Island, highlighting magmatism as crucial in driving recent shallow upper crustal faulting in the South Turkana Basin. Below this zone of extensional faulting, geochemical evidence supports a developed magma plumbing system that broadly parallels equivalent axial magmatic systems within the Main Ethiopian Rift. Overall, our data support a recent (Mid- to Late Pleistocene) transition to magma-driven axial extension in the Lake Turkana rift. Supplementary material: Supplementary text and the fault, volcanic cone and radiocarbon age data utilized in this study are available at https://doi.org/10.6084/m9.figshare.c.6026624

Detection of Magma Beneath the Northern and Southern Rift Zones of Axial Seamount at the Juan de Fuca Ridge

AbstractAxial Seamount is an active hotspot‐related volcanic system located along the Juan de Fuca Ridge (JdFR) that includes a central volcano and bounding northern and southern rift zones (NRZ and SRZ). Three documented volcanic eruptions in 1998, 2011, and 2015 included dike propagation into and eruptions within the rift zones that are believed to have been sourced from the well‐imaged large magma reservoir found beneath the central volcano. However, areas beyond the central volcano have not been explored for potential magma sources that could have contributed to these events, and geochemical studies of older rift zone lavas indicate differences in compositions suggestive of magma reservoirs fed by more mid‐ocean ridge‐dominated mantle sources. In this study, we analyze multichannel seismic data acquired in 2002 to characterize the internal crustal structure of the rift zones. The new reflectivity images reveal small (&lt;5 km wide) and discontinuous crustal magma bodies at depths of ∼1.5 to 4 km beneath and in the vicinity of the rift zone lava flows from the three eruptions. We also image wide magma bodies within the overlap regions between the rift zones and neighboring segments of JdFR including a 6.4 km wide body under the east flank of NRZ and a 1‐km wide, ∼400 to 500 m, thick body near the base of the crust under the SRZ‐Vance overlap basin. Collectively the new observations indicate that multiple small crustal magma bodies underlie Axial segment, in addition to the main reservoir, and likely contribute to rift zone magmatism with implications for interpretations of seismicity patterns and lava flow compositions.

Generation and evolution of the oceanic lithosphere in the North Atlantic

Half a century ago, our view of the Earth shifted from that of a Planet with fixed continents and ancient stable ocean basins to one with wandering continents and young, active ocean basins, reviving Wegener’s Continental Drift that had rested dormant for years. The lithosphere is the external, mostly solid and relatively rigid layer of the Earth, with thickness and composition different below the oceans and within the continents. We will review the processes leading to the generation and evolution of the Earth’s lithosphere that lies beneath the oceans. We will discuss how the oceanic lithosphere is generated along mid-ocean ridges due to upwelling of convecting hot mantle. We will consider in particular lithosphere generation occurring along the northern Mid Atlantic Ridge (MAR) from Iceland to the equator, including the formation of transform offsets. We will then focus on the Vema fracture zone at 10°–11° N, where a ~ 300 km long uplifted and exposed sliver of lithosphere allows to reconstruct the evolution of lithosphere generation at a segment of the MAR from 25 million years ago to the Present. This axial ridge segment formed 50 million years ago, and reaches today 80 km in length. The degree of melting of the subridge mantle increased from 16 million years ago to today, although with some oscillations. The mantle presently upwelling beneath the MAR becomes colder and/or less fertile going from Iceland to the Equator, with “waves” of hot/fertile mantle migrating southwards from the Azores plume. Scientific revolutions seem to occur periodically in the history of Science; we wonder when the next revolution will take place in the Earth Science, and to what extent our present views will have to be modified.

Agreement of a Portable Motion Capture System to Analyze Movement Skills in Children

ABSTRACT This study evaluated the agreement between Kinect V2 with AssessLink and Vicon motion capture systems in children performing the vertical jump (JL) and forward leap (Leap). Eighteen healthy children (5–17 years) performed the movements while recorded simultaneously by both motion capture systems. Spearman correlation (ρ) and Bland-Altman were used to determine joint angle agreement. Overall, agreement varied by body segment, movement type, and phase. JL for knees and shoulder ranged from ρ = −.220 to .543; bias = 8.1 to 23.0° and ρ = −.743 to .410; bias = 8.1 to 56.5°, respectively. Leap had poorer correlation and bias for the appendicular segments (ρ = −.091 to .306; bias = −47.5 to 73.7°) than axial segments (ρ = .345 to .553; bias = 11.3 to 22.9°). The Kinect V2 should not replace criterion kinematic systems, but may improve gross motor assessment methods when selecting for specific movement observations.

Characteristics of Anterior Segment in Congenital Ectopia Lentis: An SS-OCT Study.

Purpose To investigate the characteristics of anterior chamber angle parameters in congenital ectopia lentis (CEL) patients and to evaluate the sensitivity and specificity of anterior segment parameters in distinguishing CEL from healthy controls. Setting. Zhongshan Ophthalmic Center, Guangzhou, China. Design Cross-sectional study. Methods 35 CEL patients and 35 age- and sex-matched healthy controls were recruited. Axial length (AL) and anterior segment parameters including anterior chamber width (ACW), angle open distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA), and trabecular-iris angle (TIA) were measured. All the above parameters and the ratio index of angle parameters, which was defined as the angle parameter value of the narrower side to that of the contralateral side, were compared between CEL and controls. Receiver operating characteristic (ROC) curves were also plotted to evaluate the diagnostic performance of anterior chamber angle parameters in CEL patients. Results All angle parameters of the contralateral side to the dislocated lens side were significantly smaller than those of the dislocated lens side in CEL (all P < 0.05). For the diagnostic performance of anterior chamber angle parameters, the ratio index of TIAr500 combined with TIAr750 had the best diagnostic performance for CEL screening (AUC = 0.798), and TIAr500 of 0.887 and TIAr750 of 0.917 were detected to be the optimal cut-off points, representing a sensitivity of 89.8% and specificity of 68.7%. Conclusion The contralateral side to the dislocated lens side in the CEL had a narrower anterior chamber angle. TIAr500 combined with TIAr750 is the optimal combination strategy for ectopia lentis screening.

CT scan versus bioelectrical impedance spectrometry sarcopenia assessment to predict chemotherapy toxicity in early breast cancer.

12078 Background: There is growing literature on the impact of the progressive loss of skeletal muscle known as sarcopenia in women with early breast cancer (EBC). Imaging techniques such as Computed Tomography (CT) scans are the most studied methods to detect sarcopenia in patients with cancer; however, most patients with EBC do not require routine CT scans. Bioelectrical impedance spectrometry (BIS) is a method that does not expose patients to radiation and provides measurements to assess sarcopenia instantaneously. The extent to which BIS-assessed sarcopenia correlates with CT-assessed sarcopenia is uncertain. It is also unclear whether sarcopenia detected with either method can be associated with chemotherapy tolerance To address these questions, we evaluated the correlation between CT and BIS sarcopenia and associations of sarcopenia by each method with chemotherapy related outcomes in patients with EBC. Methods: This retrospective study identified patients with EBC who received chemotherapy (ACT, TC, TH, THP), underwent BIS analyses (ImpediMed) at any point between diagnosis and treatment completion and also received a CT abdomen including L3 level. Axial CT L3 segments were analyzed using Slice-O-Matic software. CT L3, and BIS generated the Skeletal Muscle (SM). Skeletal Muscle Index (SMI) was then calculated to assess for sarcopenia: BIS SMI= (SM in kg)/ (patient height, m2) and CT L3 SMI (SM cm2/ height m2). Patients were divided into normal SMI, and sarcopenia (if BIS was used SMI &lt;6.75 kg/m2 and if CT SMI &lt;40 cm2/m2). Patient medical records were reviewed for patient characteristics, grade 3 and 4 toxicity, including neuropathy symptoms, chemotherapy dose reductions, early treatment discontinuation or need for hospitalization during chemotherapy treatment. Spearman's rank coefficient was used to assess the correlation between CT SMI and BIS SMI. Multivariable logistic regression was used to associate sarcopenia with outcomes, controlling for age and BMI. Results: 361 patients received chemotherapy, underwent BIS; of those 171 had L3 CT scans. The correlation between L3 CT SMI and BIS SMI was r= 0.64 p&lt;0.0001. In the multivariable model, sarcopenia assessed by L3 CT scan was associated with chemotherapy dose reduction (CI 0.04-0.60 p=0.01) and neuropathy (CI 0.10-0.95 P=0.04) but not with grade 3 or 4 chemotherapy toxicity (CI 0.13-1.09 p=0.07), early treatment discontinuation (p=0.3) or hospitalization (p=0.60). Sarcopenia assessed by BIS was associated with grade 3 or 4 chemotherapy toxicity (CI 0.2-0.83 p=0.01), neuropathy (CI 0.1-0.51 p=0.0003), early treatment discontinuation (OR 0.26 CI 0.11-0.80 p=0.001), and hospitalization (CI 0.12-0.68 p=0.004). Conclusions: There is a strong correlation between L3 CT scan and BIS screened sarcopenia in patients with EBC. Sarcopenia detected with either CT L3 or BIS is associated with worse chemotherapy tolerance.

Strain Accommodation by Intrusion and Faulting in a Rift Linkage Zone: Evidences From High‐Resolution Topography Data of the Afrera Plain (Afar, East Africa)

AbstractAt mature magma‐rich continental rifts, extension focuses along discrete axial segments where magmatism and diking are important in accommodating plate divergence. However, the role of magma in influencing the deformation at rift–rift offsets is still unclear as direct observations are rare. Here, we exploited high‐resolution Pléiades‐1 tri‐stereo imagery to produce the first 1 m Digital Elevation Model of the Afrera Plain linkage zone between the Erta Ale and Tat Ali magmatic segments in Northern Afar. We carried out a detailed structural analysis of both tectonic and magmatic features in the area and observed different trends and kinematics of these features. Magmatic features at Afrera strike N160°E ± 5°E, similar to the Erta Ale segment and perpendicular to the extension direction. Conversely, tectonic features fall into two families of ∼NW‐SE‐ and ∼NS‐striking oblique faults with right‐lateral and left‐lateral components, respectively, as shown by Riedel shears. We interpret the extension direction of tectonic features using observed opening of fractures, previous seismic, and InSAR‐based fault models and from that expected for the mapped conjugate fault pattern. While the results show scatter in the range of N46°E–N68°E, it is similar within error to the regional extension direction. The simplest model that explains our data is that in the linkage zone there is both extensional and shear strain. The dikes accommodate only extension, while conjugate oblique faults accommodate extension and shear strain. Our study shows that both magmatism and faulting are important during rift segment interaction and linkage.

Particle mixing and segregation behaviors in the rotating drums with adjacent axial segmentations in different speed directions

The axial mixing and segregation behavior of particles with different properties is a complicated movement process, whose mechanism is still indistinct. Consequently, it is very important to explore dynamic repose angle and flow characteristics of the particles along the axial direction during the mixing and segregation process. Focusing on the mixing and segregation phenomenon in the rotary drum, this paper studies the particle mixing and segregation behavior by changing the speed direction of adjacent axial segmentations. The results show that alternating axial segregation band characteristics can be formed in adjacent axial segmentations with same velocity direction, while the overall mixing degree is better under the condition of the opposite velocity direction. Although the different rotational speed directions of adjacent axial segmentations will cause opposite axial mixing and segregation phenomenon, the general rules of the dynamic angle of repose and axial flow velocity are similar in the rotary drum. In addition, the axial flow structure of the binary particles varies with rotational speed direction of the adjacent axial segments, but not with the drum length to diameter (L / D) ratio and particle filling rate.

Visualization of the distal tibial plafond articular surface using four established approaches and the efficacy of instrumented distraction: a cadaveric study

PurposeDirect visualization is a very effective method in accomplishing adequate articular surface reconstruction in fracture repair. This study investigates distal tibial plafond articular surface visibility using the anteromedial, anterolateral, posteromedial, and posterolateral approaches, the effect of instrumented distraction on visibility, and which zones of the articular surface are visible for each approach.MethodsThe anteromedial, anterolateral, posteromedial, and posterolateral approaches to the distal tibial plafond were performed on 16 cadaveric ankle specimens. The articular surface visualization for each approach was marked using an electrocautery device with manual and instrumented distraction. Articular surface visualization was photographically documented. Digital axial segmentation and quantitative analysis of the visualized distal tibial plafond articular surface were performed.ResultsWith manual distraction, distal tibial plafond articular surface visualization, expressed in percent of overall articular surface, was limited to 9% (SD ± 9) for the anteromedial, 24% (SD ± 18) for the anterolateral, 26% (SD ± 10) for the posteromedial, and 30% (SD ± 18) for the posterolateral approaches. Using instrumented distraction significantly improved articular surface visualization in all instances (p < 0.001). The anteromedial approach visible articular surface increased to 63% (SD ± 13), the anterolateral to 72% (SD ± 22), the posteromedial to 62% (SD ± 11), and the posterolateral to 50% (± 17).ConclusionThis study demonstrates the efficacy of instrumented distraction when attempting surgical visualization of the distal tibial plafond articular surface. Knowledge of approach specific articular surface visibility may assist the surgeon in choosing the appropriate approach(es) based on case-specific distal tibial plafond fracture patterns.Level of evidenceIV, cadaver study.

Based on morphology and molecular data, Palisada rigida comb. nov. and Laurencia decussata comb. et stat. nov. (Rhodophyta, Rhodomelaceae) are proposed

Inspecting herbaria collections of Laurencia rigida highlighted frequent misidentifications between L. rigida and L.heteroclada f. decussata, two poorly studied taxa from Australia. Recent collections of DNA material, including from topotypematerial, allowed for re-examination of these two taxa using molecular techniques. Detailed morphological andmolecular analyses based on two markers (rbcL and COI-5P) strongly supported these two taxa as being distinct fromeach other and requiring nomenclatural changes. Comprehensive morphological analyses highlighted features useful foraccurate identifications. Interestingly, L. rigida was found to belong to the genus Palisada with evidence from both themorphology and molecular data. Therefore, this study proposed recognizing L. rigida as Palisada rigida comb. nov. Moleculardata for L. heteroclada f. decussata on the other hand supported its separation from L. heteroclada, with too greata molecular distance to be considered a variety. Morphological characters that best separated P. rigida from L. decussataincluded seven characters; number of pericentral cells per vegetative axial segment, the presence of secondary pit connections,the presence of lenticular thickenings, tetrasporangia alignment, the presence of corps en cerise, holdfast morphology,and overall plant shape. Morphologically, L. heteroclada f. decussata was also separated from L. heteroclada,particularly by the following characteristics; ultimate branchlets morphologies, lower order branch lengths, primary axisand holdfast morphologies. Therefore, it was proposed that L. heteroclada f. decussata is recognized at a species level asL. decussata comb. et stat. nov.