Shape Asymmetry Research Articles

Numerical Study of Aerodynamic Characteristics of No-Swinging and Free-to-Swing Cross Parachute

During wind-tunnel experiments on parachutes, it is common to either fix the apex of the canopy to maintain a specific angle of attack or only fix the confluence point of the suspension lines to allow the canopy to move freely. These no-swinging and free-to-swing conditions affect considerably the aerodynamic characteristics of the parachute. This paper investigates the influence of these conditions on the aerodynamic characteristics and dynamic motion characteristics of both symmetric cross parachutes with eight equal suspension lines, and asymmetric cross parachutes with two (of eight) shortened suspension lines. The research reveals that the canopy of a no-swinging cross parachute exhibits a spinning motion around its axis. The free-to-swing parachute undergoes a conical swing motion around the suspension-line confluence point. The frequency of spin and conical swing increases in proportion to . The magnitude and direction of the lift force varies periodically owing to the conical swing of the free-to-swing parachute. Conversely, the no-swinging parachute, at a fixed angle of attack, maintains a comparatively stable lift force. The free-to-swing asymmetric cross parachute produces a stronger lift force because of the larger swing angle compared to the symmetric parachute. The resultant asymmetry in the aerodynamic shape caused by the shortening of suspension lines has minimal effect on aerodynamic characteristics.

Evaluation of Central Quadrentectomy and Immediate Reconstruction in Patients with Retroareolar Breast Cancer

Abstract Background Centrally located breast cancer represents 5–20 % of all breast cancer cases. Oncoplastic breast surgery combines oncological principles with plastic surgical techniques; it requires knowledge of anatomy, and appreciation of symmetry, esthetics and breast function. Aim of the Work The aim of the current study is to present and assess multiple techniques of surgical outcome of oncoplastic techniques following the resection of centrally located breast cancer. Patients and Methods This prospective study comprised of 24 female patients with central breast cancer from November 2018 to Feb 2020 at the department of surgery Ain-Shams University Hospitals. Patients were followed up every 3 months for at least 12 months. Informed consent was obtained from the patients, and this study was approved by Al.Demerdash Hospital ethics committee. Results In our study, statistics shows to some extent, When NAC is not involved Flierl and Hanker [11] reported satisfactory results with central quadrentectomy and immediate reconstruction in patients with retroareolar breast cancer. The mean age was 49.83 ± 7.6 years (range; 39 to 60). 13/24 patients (54.16%) were premenopausal while 11/24 (45.83%) patients were postmenopausal. 5 patients had diabetes mellitus and the rest of patients were non diabetic. Four patients (16.6%) had positive family history of breast cancer. Six patients had nipple retraction (25%). The mean tumour size was 2.52 ± 0.64 cm cm (0.9-2.8 cm). The spectrum of safety margin ranged from (1.9-2.8 cm) the mean safety margin in our study is 2.19±0.32, The overall percentage of complications was 5/24 (20.8%). Pathological nipple infiltration was found in 12 cases (50%) showed clinical and/or radiological evidence of nipple involvement and underwent resection of the NAC (Grissoti and Melon slice techniques). 14 patients (58.33%) had positive axillary lymph nodes, all staged as pN1; while the other 10 patients (41.66%) where staged as pN0. There is significant statistical difference between the two groups; Patient dissatisfaction is due to presence of scar, breast shape asymmetry and absence of NAC as in Grisotti and Melon slice groups or asymmetry as in Inferior pedicle group. Conclusion Multiple oncoplastic breast surgery techniques used in treatment of CLBC with good cosmetic and oncological outcome but need more training to have good results.

The effect of sex and age on facial shape directional asymmetry in adults: A 3D landmarks-based method study.

Facial directional asymmetry research, including age-related changes, is crucial for the evaluation of treatment of craniofacial malformations/trauma in orthodontics, facial surgery and forensic sciences. The aim was to describe facial directional asymmetry (DA) in different age categories of adults using 3D methods. According to our hypothesis, facial shape DA (1) depends on sex; (2) differs among age groups; and (3) has wider variability in older age. A cross-sectional sample of healthy Czech adults without craniofacial trauma or anomalies consisted of 300 3D facial models (151 females). The age-range in the study was between 20-80 years. The shape asymmetry of 28 3D landmarks was evaluated using geometric morphometrics and multivariate statistics. The manifestation of DA was similar in both sexes and in each age category; however, there were some statistical differences. In contrast to the ideal symmetrical face, the mean asymmetrical faces tended to create a slightly bent "C" shape of the midline. Therefore, the upper face was rotated slightly clockwise and the lower face counter-clockwise. The right eye was located slightly higher, with the nasal tip and mandibular region tilting to the left. Sex differences in facial DA were significant before the age of 40. DA was more significant in the youngest males than in the oldest, while the women's DA did not change. The DA patterns were similar in both sexes and in all age categories (a slightly bent C shape of the midline); however, some significant local differences between male age groups were found. A significantly more pronounced asymmetry compared to other age groups was found only in the youngest males from 20 to 40 years. Moreover, significant sexual dimorphism of DA rapidly decreased after middle age, likely caused by the same age-related changes of the face during aging.

Reducing the cyclic tension-compression asymmetry and cyclic hardening of ZK61 magnesium alloy via the compression-extrusion process

In order to reduce the cyclic tension-compression asymmetry and cyclic hardening that exists widely in magnesium alloys, ZK61magnesium alloys with different texture intensities and grain sizes were fabricated by conventional extrusion and compression-extrusion process. It was found that the compression-extrusion process had a remarkable effect on the texture weakening and grain refining, which significantly improved monotonic tension-compression asymmetry and cyclic tension-compression asymmetry. Under their combined effects, the {10–12} twinning-detwinning behavior of ZK61 magnesium alloy during cyclic tension-compression deformation was effectively suppressed, resulting in a remarkable reduction of the difference of peak stresses in tension and compression. In the meantime, shape asymmetry embodied in a concave-up characteristic of the cyclic hysteresis loops was almost eliminated as the weakening of the detwinning-prismatic slip transition. Twinning-promoted dislocation pile-up and twinning-induced grain segmentation were significantly attenuated with texture weakening and grain refining, leading to a substantial weakening of cyclic hardening. Eventually, ZK61 magnesium alloy with low cyclic tension-compression.

Effect of four plant extracts on the mortality, population growth, and fluctuating asymmetry of Sitophilus oryzae

AbstractManagement of storage pest insects relies heavily on chemical control, and there is a need to develop more sustainable management practices. Here, we evaluated the impact of 2% ethanol plant extracts of Ajuga reptans L., Ajuga pyramidalis L. (both Lamiaceae), Urtica dioica L. (Urticaceae), and Cannabis sativa L. (Cannabaceae) plants on mortality, population growth, and developmental stability [measuring fluctuating asymmetry (FA)] of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), a worldwide stored product pest. FA refers to small, random deviations occurring between the left and right sides of bilaterally symmetrical organisms; these deviations increase in response to environmental stress, making FA a reliable method to measure the impact of stress. FA was measured by means of geometric morphometrics, a method that allows for analyzing the whole landmark configuration of the insect, rather than taking single measurements. Extracts of the mentioned plants were used to treat maize (Zea mays L., Poaceae) kernels on which experimental populations of the rice weevil were grown, and we assessed mortality after 24–72 h, population growth after 30–90 days, and developmental stability after 90 days. Screening bioassays showed that S. oryzae adults were most affected by Ajuga extracts; Ajuga spp., especially A. reptans, significantly reduced population growth. In concordance, Ajuga extracts increased FA. The effects of U. dioica and C. sativa extract were less pronounced. None of the extracts significantly affected insect mortality. Overall, it can be concluded that A. reptans and A. pyramidalis are potential sources of bioactive compounds that may be further used for S. oryzae control. The results obtained confirm that variation in body shape asymmetry can be used as an indicator of population disturbance when insects are exposed to different types of stressors.

SDSS-IV MaNGA: The incidence of major mergers in type I and II AGN host galaxies in the DR15 sample

ABSTRACT We present a study on the incidence of major mergers and their impact on the triggering of nuclear activity in 47 type I and 236 type II optically selected AGN from the MaNGA DR15 sample. From an estimate of non-parametric image predictors (Gini, M20, concentration (C), asymmetry (A), clumpiness (S), Sérsic index (n), and shape asymmetry (AS)) using the SDSS images, in combination with a Linear Discriminant Analysis Method, we identified major mergers and merger stages. We reinforced our results by looking for bright tidal features in our post-processed SDSS and DESI legacy images. We find a statistically significant higher incidence of major mergers of 29 per cent ± 3 per cent in our type I+II AGN sample compared to 22 per cent ± 0.8 per cent for a non-AGN sample matched in redshift, stellar mass, colour, and morphological type, finding also a prevalence of post-coalescence (51 per cent ± 5 per cent) over pre-coalescence (23 per cent ± 6 per cent) merger stages. The levels of AGN activity among our massive major mergers are similar to those reported in other works using [O iii] tracers. However, similar levels are produced by our AGN-galaxies hosting stellar bars, suggesting that major mergers are important promoters of nuclear activity but are not the main nor the only mechanism behind the AGN triggering. The tidal strength parameter Q was considered at various scales looking for environmental differences that could affect our results on the merger incidence, finding non-significant differences. Finally, the H-H β diagram could be used as an empirical predictor for the flux coming from an AGN source, useful to correct photometric quantities in large AGN samples emerging from surveys.

Asymmetry of Sagittal Otolith Shape Based on Inner Ear Side Tested on Mediterranean Red Mullet (Mullus barbatus Linnaeus, 1758): Comparative Analysis of 2D and 3D Otolith Shape Data

Sagittal otolith shape analysis is one of the most widespread techniques worldwide to discriminate fish stock units, as this proxy integrates both environmental and genetic factors. All previous otolith shape studies have been carried out using two-dimensional (2D) images, a partial representation of the whole shape of the otolith. However, prior to the identification of stock unit boundaries, the influence of other potential drivers controlling the otolith shape must be analysed to limit their bias. In this study, the presence of asymmetry in otolith shape depending on the inner ear side (i.e., left versus right inner ears) was tested by comparing the approaches of 2D and three-dimensional (3D) sagittal otolith shape analyses. Eighty-two red mullet adults (Mullus barbatus) from three locations in the eastern part of the Mediterranean Sea were studied. Fourier harmonic descriptors computed from 2D outlines and spherical harmonic descriptors computed from 3D meshes were used to evaluate otolith shape variation. The results of a multivariate mixed-effects model from 2D images showed that there was no asymmetry effect of inner ear side on the otolith shape in any location. There was, however, a significant geographical effect for the 2D otolith shape between the Adriatic Sea and the Levantine Sea. In contrast, 3D information showed that both side effects and geographical differences were significant. This is the first study comparing 2D and 3D data showing different results on the same sample of red mullet. These results demonstrate the importance of 3D otolith shape analysis for stock discrimination.

Horizontal transport in the bouncing ball system with a sawtooth-shaped table

The system that consists of a ball bouncing off a sawtooth-shaped table vibrating vertically is considered. The horizontal motion in this system is caused by the table shape, and we plotted the mean horizontal velocity as a function of the asymmetry of the table shape. The ball is transported in the direction which the gentler slopes face for the high-bounce parameter region. To give a description to the net asymmetric transport, we derive a simplified model using assumptions of high bounce and probabilistic collision to the left or right slopes. The simplified model exhibits a horizontal transport qualitatively similar to that observed in the original model.

Interplanetary Magnetic Field By Controls the Magnetopause Location

AbstractWe present a statistical study of interplanetary magnetic field (IMF) effects on the magnetopause location based on nearly 15,000 magnetopause crossings identified in the THEMIS A‐E, Magion 4, Geotail, and Interball‐1 satellite data. In order to exclude the dominant controlling role of the solar wind dynamic pressure, differences between observed and empirical model magnetopause distances are analyzed. We find that the magnetopause distance is significantly controlled by the IMF clock angle, not considered in the used empirical models. Furthermore, during very low Alfvén Mach numbers (MA < 4), IMF By component can induce a considerable dawn‐dusk asymmetry of the magnetopause shape. The magnetopause distance is found to be larger in the direction of the IMF vector, that is, not only the magnitude but also the orientation of the IMF By component is eventually important. The obtained results are qualitatively consistent with a magnetohydrodynamic model run at the Community Coordinated Modeling Center.

Study of drop mobility over a surface having electric charge gradient

Though different methodologies like thermal and magnetic fields have been tried to control a droplet's mobility in biochemical and medical applications, charge imprinted super-amphiphobic surface is the recent and promising development in which droplets can be transported through any predefined path over the surface. Such surfaces are electrified by impacting water droplets from varying release heights through triboelectrification. Impacting droplets on pillared surface dynamics of the same have been analyzed to understand the nature of electrostatic charge distribution generated. Further to this, droplet actuation on such surfaces with surface charge gradient has been simulated. Charge separation inside the liquid droplet and charge accumulation near the interface has been visualized to understand the phenomenon. Asymmetry in droplet shape and charge distribution has been analyzed as the reason behind the droplet actuation. The effect of different charge density gradients and surface wettability over droplet mobility has also been studied.

Impact of bruxism on craniomandibular morphology: A cone-beam computed tomographic study

ABSTRACT Objective The main goal of this work was to address craniomorphological characteristics of patients with bruxism when compared to those without bruxism using cone beam computed tomography (CBCT) imaging. Methods Seventy CBCT images of an equal number (n = 35) of orthodontic patients with and without bruxism (age range, 18–44 years) were retrospectively analyzed. Sagittal evaluation, mandibular shape, and skeletal asymmetry were systematically assessed in both groups. Results Significant differences (p < 0.05) were observed between groups for Right Articular Fossa (AF) – Axial Plane (AP) and Left AF – AP (B > NB), Right Gonial Angle (GA), Left GA, Sella-Nasion and Occlusal Plane (B < NB). Age (13%), Condyle-Gonion (18%), AF to AP (67%), and Mental-AP (16%) had the greatest impact on bruxers. Conclusion In this study, the CBCT 3D image showed significant differences in craniofacial morphology, particularly in the mandibular structure of bruxers compared with non-bruxers.

Acoustic rotation of non-spherical micro-objects: Characterization of acoustophoresis and quantification of rotational stability

Acoustic radiation force and torque arising from wave scattering have the potential to perform the biocompatible, contact-free, and precise translation and rotation of micro-objects. Controllable rotation of objects mainly relies on the use of sophisticated transducer arrays, while it is limited by the spatial Rayleigh limitation and would be costly to miniaturize the array for manipulated objects on the micron scale. Here, we make use of the shape asymmetry of an object and achieve micro-object trap and rotation using a simple standing wavefield. The conformal transformation approach is employed to map an axisymmetric, non-spherical object into a sphere, allowing fast analysis for design or real-time computer-controlled manipulation. A low-cost, simple rotational tweezing system is built, which confirms the theoretical prediction that micro-particles are trapped in the pressure nodes and remotely rotated by the action of the actuator boundaries. The rotational dynamics are guided by two stabilization modes, and Lyapunov stability analysis reveals that at least one mode leads to a stable equilibrium state. We demonstrate the significance of our approach in stably and controllably rotating micron-scale objects. The robustness and versatility of the new handy design hold promise for clinical applications and microscopic research such as drug delivery and microsurgery.

New Insights on the Multivariate Skew Exponential Power Distribution

ABSTRACT The multivariate exponential power is a useful distribution for modeling departures from normality in data by means of a tail weight scalar parameter that regulates the non-normality of the model. The incorporation of a shape asymmetry vector into the model serves to account for potential asymmetries and gives rise to the multivariate skew exponential power distribution. This work is aimed at revisiting the skew exponential power distribution taking as a starting point its formulation as a scale mixture of skew-normal distributions. The paper provides some highlights and theoretical insights on the role played by its parameters to assess two complementary aspects of the multivariate non-normality such as directional asymmetry and tail weight behavior regardless of the asymmetry. The intuition behind both issues relies on well-known mathematical ideas about skewness maximization and convex transform stochastic orderings.

Non-Hermitian control of confined optical skyrmions in microcavities formed by photonic spin–orbit coupling

Optical skyrmions formed by photonic spin–orbit (SO) coupling are of significant interest in high-dimensional optical information processing. We report the formation mechanism and non-Hermitian properties of skyrmion-like states in a circular confinement potential with photonic SO coupling, which is preferably realized in a concave-planar microcavity system. We show that the effective photonic gauge field leads to two split manifolds of degenerate skyrmions whose spin textures can be controlled via the non-Hermitian properties by introducing circularly polarized gain and loss, exhibiting dramatically discrepant evolutions at the two sides of the exceptional point (EP). Furthermore, the lifetime degeneracy can be lifted by spatially inhomogeneous pumping according to the non-Hermitian mechanism, enabling the possibility for the skyrmion laser. By introducing shape asymmetry of the confinement potential, a double EP evolution can be achieved, which allows non-Hermitian control of the SO coupled states with higher degrees of freedom. These results open the way for the non-Hermitian control of photonic spin in confined systems, which would be of great significance for the fundamentals of advanced optical information processing.

First Evidence of Axial Shape Asymmetry and Configuration Coexistence in Zn74 : Suggestion for a Northern Extension of the N=40 Island of Inversion

The excited states of N=44 ^{74}Zn were investigated via γ-ray spectroscopy following ^{74}Cu β decay. By exploiting γ-γ angular correlation analysis, the 2_{2}^{+}, 3_{1}^{+}, 0_{2}^{+}, and 2_{3}^{+} states in ^{74}Zn were firmly established. The γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2_{2}^{+}, 3_{1}^{+}, and 2_{3}^{+} states were measured, allowing for the extraction of relative B(E2) values. In particular, the 2_{3}^{+}→0_{2}^{+} and 2_{3}^{+}→4_{1}^{+} transitions were observed for the first time. The results show excellent agreement with new microscopic large-scale shell-model calculations, and are discussed in terms of underlying shapes, as well as the role of neutron excitations across the N=40 gap. Enhanced axial shape asymmetry (triaxiality) is suggested to characterize ^{74}Zn in its ground state. Furthermore, an excited K=0 band with a significantly larger softness in its shape is identified. A shore of the N=40 "island of inversion" appears to manifest above Z=26, previously thought as its northern limit in the chart of the nuclides.

Spatial Control over Catalyst Positioning for Increased Micromotor Efficiency

Motion is influenced by many different aspects of a micromotor's design, such as shape, roughness and the type of materials used. When designing a motor, asymmetry is the main requirement to take into account, either in shape or in catalyst distribution. It influences both speed and directionality since it dictates the location of propulsion force. Here, we combine asymmetry in shape and asymmetry in catalyst distribution to study the motion of soft micromotors. A microfluidic method is utilized to generate aqueous double emulsions, which upon UV-exposure form asymmetric microgels. Taking advantage of the flexibility of this method, we fabricated micromotors with homogeneous catalyst distribution throughout the microbead and micromotors with different degrees of catalyst localization within the active site. Spatial control over catalyst positioning is advantageous since less enzyme is needed for the same propulsion speed as the homogeneous system and it provides further confinement and compartmentalization of the catalyst. This proof-of-concept of our new design will make the use of enzymes as driving forces for motors more accessible, as well as providing a new route for compartmentalizing enzymes at interfaces without the need for catalyst-specific functionalization.

Asymmetric distribution of aminophospholipids stiffens fluid membranes.

Cellular envelopes contain a large number of lipid species that distribute asymmetrically between the two leaflets of the bilayer. For example, mammalian plasma membranes are composed of an outer leaflet enriched in cholinephospholipids, while the majority of the aminophospholipids are confined to the inner leaflet. Membrane asymmetry can theoretically lead to distinct effects regarding its elastic behavior, either due to lipid specific properties (e.g. size, shape), or simply lipid over/under-crowding of a given leaflet. Corresponding experimental data are scarce. This prompted us to determine the structure and bending rigidity of minimal mammalian plasma membrane mimics composed of milk sphingomyelin (MSM), palmitoyl oleoyl phosphatidylcholine (POPC), palmitoyl oleoyl phosphatidylethanolamine (POPE), and palmitoyl oleoyl phosphatidylserine (POPS) using small-angle neutron/X-ray scattering and neutron spin echo spectroscopy. Most strikingly, we observed an anomalous stiffening of freely-floating fluid vesicles (size ∼ 100 nm) in case of inner leaflets composed of POPE/POPS mixtures and outer leaflets enriched in POPC. That is, the bending rigidities of POPCout/(POPE/POPS)in vesicles did not only exceed those of their scrambled (symmetric) analogs, but also those of symmetric vesicles mimicking either their inner and outer leaflets. Addition MSM in the outer leaflet reduced but not abolished this effect, possibly due to hydrocarbon chain interdigitation. To reconcile our findings, we speculate that lipid shape and charge asymmetry may increase the weight of short-wavelength undulatory modes in membranes by inducing a coupling at distances smaller than the membrane thickness.

Diagnostic Usefulness of Diffusion-Weighted MRI for Axillary Lymph Node Evaluation in Patients with Breast Cancer.

This study aimed to determine whether apparent diffusion coefficient (ADC) and morphological features on diffusion-weighted MRI (DW-MRI) can discriminate metastatic axillary lymph nodes (ALNs) from benign in patients with breast cancer. Two radiologists measured ADC, long and short diameters, long-to-short diameter ratio, and cortical thickness and assessed eccentric cortical thickening, loss of fatty hilum, irregular margin, asymmetry in shape or number, and rim sign of ALNs on DW-MRI and categorized them into benign or suspicious ALNs. Pathologic reports were used as a reference standard. Statistical analysis was performed using the Mann-Whitney U test and chi-square test. Overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of DW-MRI were calculated. The ADC of metastatic ALNs was 0.905 × 10-3 mm2/s, and that of benign ALNs was 0.991 × 10-3 mm2/s (p = 0.243). All morphologic features showed significant difference between the two groups. The sensitivity, specificity, PPV, NPV, and diagnostic accuracy of the final categorization on DW-MRI were 77.1%, 93.3%, 79.4%, 92.5%, and 86.2%, respectively. Our results suggest that morphologic evaluation of ALNs on DWI can discriminate metastatic ALNs from benign. The ADC value of metastatic ALNs was lower than that of benign nodes, but the difference was not statistically significant.

Relationship between the bilateral ratios of the thoracic shape and electromyographic activity of the thoracic and lumbar iliocostalis muscles during thoracic lateral translation.

[Purpose] This study aimed to determine the relationship between thoracic lateral deviation, the bilateral ratio of the thoracic shape, and the bilateral ratio of the thoracic and lumbar iliocostalis muscles during resting sitting and thoracic lateral translation. [Participants and Methods] We included 23 healthy adult males in the study. The measurement tasks were resting sitting and thoracic lateral translation relative to the pelvis. The thoracic lateral deviation and bilateral ratio of the upper and lower thoracic shapes were measured using three-dimensional motion capture. The bilateral ratio of the thoracic and lumbar iliocostalis muscles were measured using the surface electromyographic recording. [Results] The bilateral ratio of the lower thoracic shape was significantly positively correlated with the thoracic translation distance and the bilateral ratio of the thoracic and iliocostalis muscles. In addition, the bilateral ratio of the thoracic iliocostalis muscles was significantly negatively correlated with the bilateral ratios of the lower thoracic shape and lumbar iliocostalis muscles. [Conclusion] Our findings showed that the asymmetry of the lower thoracic shape is associated with left lateral deviation of the thorax at rest and thoracic translation distance. In addition, the thoracic and lumbar iliocostalis muscle activity differed between the left and right translations.

Magnetically actuated swimming and rolling erythrocyte-based biohybrid micromotors.

Erythrocytes are natural multifunctional biomaterials that can be engineered for use as micro robotic vectors for therapeutic applications. Erythrocyte based micromotors offer several advantages over existing bio-hybrid micromotors, but current control mechanisms are often complex, utilizing multiple external signals, such as tandem magnetic and acoustic fields to achieve both actuation and directional control. Further, existing actuation methods rely on proximity to a substrate to achieve effective propulsion through symmetry breaking. Alternatively, control mechanisms only requiring the use of a single control input may aid in the translational use of these devices. Here, we report a simple scalable technique for fabricating erythrocyte-based magnetic biohybrid micromotors and demonstrate the ability to control two modes of motion, surface rolling and bulk swimming, using a single uniform rotating magnetic field. While rolling exploits symmetry breaking from the proximity of a surface, bulk swimming relies on naturally occurring shape asymmetry of erythrocytes. We characterize swimming and rolling kinematics, including step-out frequencies, propulsion velocity, and steerability in aqueous solutions using open-loop control. The observed dynamics may enable the development of future erythrocyte micromotor designs and control strategies for therapeutic applications.