Terms Of Symmetry Research Articles

Breast Reconstruction after Surgical Treatment of Ductal Carcinoma In Situ.

The role of plastic surgeon in breast reconstruction is mandatory in those cases of ductal carcinoma in situ (DCIS) requiring a wide surgical excision. The reconstructive treatment must be tailored on each patient with the aim to obtain a good cosmetic result in terms of form and symmetry, avoiding surgical complications.

Dirac equation perspective on higher-order topological insulators

In this Tutorial, we pedagogically review recent developments in the field of non-interacting fermionic phases of matter, focusing on the low-energy description of higher-order topological insulators in terms of the Dirac equation. Our aim is to give a mostly self-contained treatment. After introducing the Dirac approximation of topological crystalline band structures, we use it to derive the anomalous end and corner states of first- and higher-order topological insulators in one and two spatial dimensions. In particular, we recast the classical derivation of domain wall bound states of the Su–Schrieffer–Heeger (SSH) chain in terms of crystalline symmetry. The edge of a two-dimensional higher-order topological insulator can then be viewed as a single crystalline symmetry-protected SSH chain, whose domain wall bound states become the corner states. We never explicitly solve for the full symmetric boundary of the two-dimensional system but instead argue by adiabatic continuity. Our approach captures all salient features of higher-order topology while remaining analytically tractable.

Departing from an ideal: An asymmetric, bimodal and non‐Equatorial latitudinal gradient of marine diversity in Western Atlantic burrowing shrimps (Decapoda: Axiidea and Gebiidea)

AbstractAimDespite the generality of the latitudinal gradient of species diversity (LDG) phenomenon, there is growing evidence showing deviations from an idealized pattern, that is, a single peak of species richness symmetrically centred in the Equator, but the underlying causes remain little studied. We here evaluate the existence of departures from the idealized LDG in a group of marine crustaceans and the explanatory role of environmental variables.LocationCoastal shelf (<200 m depth) along the Western Atlantic coast (46°N–47°S).TaxonBurrowing shrimps (Decapoda: Axiidea and Gebiidea).MethodsWe assessed the shape of the LDG in 100 burrowing shrimp species using the reported latitudinal ranges of distribution. Species richness was calculated in one‐degree latitude bands using a range‐through approach. The shape of the LDG was statistically evaluated in terms of latitudinal symmetry, number of modes and location. We evaluated the importance of 10 environmental variables (proxies of different hypothesis categories) predicting the LDG using a random forest model.ResultsBurrowing shrimps exhibit an increase in diversity towards the tropics, but departures to the idealized LDG were evident. The LDG is asymmetric between hemispheres and bimodal (two peaks within the tropics), and this trend cannot be explained in terms of sampling artifacts. A random forest model explains 92% of species richness, but the only significant variables were bottom seawater temperature, bottom seawater salinity, bottom seawater temperature range, and tidal range. These predictors were nonlinearly related to species richness, whereas only bottom seawater temperature and bottom seawater salinity showed a significant phylogenetic signal.Main conclusionsThe LDG of burrowing shrimps is driven by ecophysiological restrictions of species, reflecting the role of evolutionary (i.e. ‘time for species accumulation’ and/or ‘diversification dynamics’) and ecological processes (i.e. ‘ecological limits’). Departures from the idealized LDG could be explained by the nonlinear responses of species richness to environmental conditions, the spatial structure of these environmental conditions, and a varying degree of phylogenetic conservatism of key ecophysiological constraints.

Superior Pedicle Breast Reduction with Prefiguration of Final Shape: A 10-year Retrospective Study.

Background:Breast reduction, also defined as reduction mammaplasty, is one of the most common procedures performed in aesthetic surgery. Multiple techniques have been proposed throughout the years and several classification systems have been adopted according to: type of incision, pedicle blood supply (cutaneous, glandular, dermoglandular), extent of undermining, excision area, simultaneous or separate tissue excision (fat/gland, skin, or both), and combination of the aforementioned. In the present article, we share our 10 years’ experience with reduction mammaplasty and we describe our personal technique, a modified superior pedicle breast reduction.Methods:We performed a retrospective analysis on 823 consecutive patients undergoing either aesthetic or functional reduction mammaplasty at Humanitas Research Hospital between 2009 and 2018. For each patient, we evaluated the mean resection volume and complication rate. We also assessed patients’ satisfaction (VAS scale) and aesthetic outcome (assessed by independent surgeons, scale from 1 to 5).Results:The average patient age was 48, ranging from 17 to 77 years. The average operative time was 77 minutes, ranging from 62 to 123 minutes. After a thorough follow-up of these patients, we can conclude that our technique has a low complication rate, patients’ satisfaction is excellent, and the result is stable over time in terms of shape and symmetry (the mean VAS score was 8.1). Postoperative surgeon’s photographs evaluation scores were 4.5 ± 0.5. Average resected volume was 860gr.Conclusion:The proposed technique is safe, fast, and simple with a relatively short learning curve, making it didactic and intuitive for young surgeons.

Fracton phases via exotic higher-form symmetry-breaking

We study p-string condensation mechanisms for fracton phases from the viewpoint of higher-form symmetry, focusing on the examples of the X-cube model and the rank-two symmetric-tensor U(1) scalar charge theory. This work is motivated by questions of the relationship between fracton phases and continuum quantum field theories, and also provides general principles to describe p-string condensation independent of specific lattice model constructions. We give a perspective on higher-form symmetry in lattice models in terms of cellular homology. Applying this perspective to the coupled-layer construction of the X-cube model, we identify a foliated 1-form symmetry that is broken in the X-cube phase, but preserved in the phase of decoupled toric code layers. Similar considerations for the scalar charge theory lead to a framed 1-form symmetry. These symmetries are distinct from standard 1-form symmetries that arise, for instance, in relativistic quantum field theory. We also give a general discussion on interpreting p-string condensation, and related constructions involving gauging of symmetry, in terms of higher-form symmetry.

Otoplasty: Rasps or Puncture Needles? A Clinical Trial.

Up to 25% of otoplasties can lead to complications, indicating the need for technical refinement. Stenström's anterior auricular cartilage scoring is used in combination with Mustardé's technique to treat the antihelix deformity in several series, with good results. Both can be performed with different instruments such as rasps or puncture needles. This study aims to compare the use of puncture needles and rasps for anterior cartilage scoring in otoplasty. The association of Stenström and Mustardé were the basic technique. Anatomical and aesthetic endpoints were assessed. We also reviewed postoperative complications. Forty-two patients with prominent ears and no previous surgery were randomly assigned needle or rasps technique. They were operated on by the first-year plastic surgery resident in the years of 2014 and 2019. The patients were followed up and reviewed at days 2 and 15, as well as 1, 3 and 6months postoperatively. The endpoints were evaluated through pre- and postoperative photographs by four experienced plastic surgeons unaware of the techniques used in each case. Patient satisfaction was searched by a "yes" or "no" question. Surgical time and postoperative edema were evaluated in 20 patients (2014 group). There were no statistical differences between the groups in terms of overall results, symmetry, antihelix shape or cartilage fracture. Ninety-five percent of the patients were satisfied with the outcome. The needle technique resulted in less postoperative edema and shorter surgical time. Anterior cartilage scoring used in combination with posterior mattress sutures to treat poorly formed antihelical fold has good and similar results when performed with rasps or puncture needles, even in unexperienced hands. The needle has the advantage of leading to a comparable surgical time and less postoperative edema, while not requiring any special surgical instrument. This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the table of contents or the online instructions to authors www.springer.com/00266 .

Anomalous changes of electric quadrupole order at low temperatures in the spin-orbit coupled metal Cd2Re2O7

Magnetic torque measurements in the spin-orbit coupled metal ${\mathrm{Cd}}_{2}{\mathrm{Re}}_{2}{\mathrm{O}}_{7}$ have been performed to investigate unique multipole orders associated with inversion symmetry breaking. The torque curves as a function of field angle are decomposed into two terms, a fourfold symmetry term (${\ensuremath{\tau}}_{4}\ensuremath{\propto}{H}^{4}$), corresponding to an electric quadrupole order, and a twofold symmetry term (${\ensuremath{\tau}}_{2}\ensuremath{\propto}{H}^{2}$), likely corresponding to an electric toroidal quadrupole order at low temperatures. Below 20 K, a strong enhancement of the fourfold symmetry term following a large phase change is observed toward the superconducting transition whereas no such behavior is evident in the twofold symmetry term. The results show anomalous changes of the electric quadrupole order at the low temperatures.

Sub-muscular Reconstruction after NAC Sparing Mastectomy: Direct to Implant Breast Reconstruction with Human ADM Versus Tissue Expander.

Nipple areola complex (NAC) sparing mastectomy allows good oncological and aesthetic results. The study compares the results, in terms of self-evaluated satisfaction and symmetry, of direct to implant (DTI) sub-muscular breast reconstruction, with the aid of human acellular dermal matrix (ADM) versus two-stage reconstruction with sub-muscular tissue expander, followed by implant. This is a retrospective, observational, single-center, non-randomized, case-control study. Inclusion criteria were: unilateral NAC sparing mastectomy at Forlì Hospital between 2014 and 2018; sub-muscular reconstruction; minimum follow-up of 12months from the reconstructive stage; no history of radiotherapy. Patients were divided into two groups: group A included patients who underwent DTI breast reconstruction with the aid of human ADM; group B were those who underwent a two-stage reconstruction with tissue expander then implant. We collected data on: (1) Self-evaluated satisfaction by Breast Q questionnaire (scores from 0 to 100). (2) Observer-evaluated symmetry. Bi-dimensional photographs were collected and evaluated by 11 breast surgeons blinded to each other, who assigned a score for symmetry (from 0 to 10). (3) Symmetry of anthropometric measures collected by hand and volume estimated by Breast V application. Group A included 28 patients; group included B 26 patients. Breast-Q questionnaires reported the following results: satisfaction with breasts in group A 65 ± 12 versus group B 68 ± 14; satisfaction with outcome in group A 88 ± 16 versus group B 93 ± 11; psychosocial well-being in group A 71 ± 20 versus group B 76 ± 17; sexual well-being in group A 63 ± 26 versus group B 60 ± 13; physical well-being in group A 68 ± 15 versus group B 60 ± 12. The average symmetry breast score assigned to group A was 6.9, versus group B 7.2. Regarding the anthropometric measures in group A, the differences between right and left were major to those in group B. Regarding breast volume, the mean difference between right and left in group A was 31.89cc ± 24.97, whereas in group B was 25.46cc ± 23.59. Our data show better symmetry and better psychosocial well-being in the two-stage reconstruction, and higher satisfaction with sexual and physical well-being in DTI reconstructions. These aspects should be discussed with the patient while collecting the informed consent. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Asymmetries in the Technique and Ground Reaction Forces of Elite Alpine Skiers Influence Their Slalom Performance

Background: Although many of the movements of skiers are asymmetric, little is presently known about how such asymmetry influences performance. Here, our aim was to examine whether asymmetries in technique and the ground reaction forces associated with left and right turns influence the asymmetries in the performance of elite slalom skiers. Methods: As nine elite skiers completed a 20-gate slalom course, their three-dimensional full-body kinematics and ground reaction forces (GRF) were monitored with a global navigation satellite and inertial motion capture systems, in combination with pressure insoles. For multivariable regression models, 26 predictor skiing techniques and GRF variables and 8 predicted skiing performance variables were assessed, all of them determining asymmetries in terms of symmetry and Jaccard indices. Results: Asymmetries in instantaneous and sectional performance were found to have the largest predictor coefficients associated with asymmetries in shank angle and hip flexion of the outside leg. Asymmetry for turn radius had the largest predictor coefficients associated with asymmetries in shank angle and GRF on the entire outside foot. Conclusions: Although slalom skiers were found to move their bodies in a quite symmetrical fashion, asymmetry in their skiing technique and GRF influenced variables related to asymmetries in performance.

‘Sequence graphics’ for gross anatomy diagrams and their objective evaluation

Background and Objectives: Drawing diagrams is an integral part of learning anatomy. The objective of the study was to evaluate sequence graphics to impart drawing skills among medical undergraduates. The other objective of the study was to design and evaluate an objective method of assessment of clinically relevant moderately complex gross anatomy diagrams. Methodology: In an experimental study, participated by 92 students, were asked to draw coronal section of male pelvis (moderately complex diagram) projected on the board. The same diagram was redone with PowerPoint in such a way that each component appears sequentially on command from the teacher, technique called sequence graphics. Sequence labelling followed appearance of each component. The perineal membrane was the key component. Prostate gland (with urethra), deep transverse perineal muscle (with bulbourethral glands) and Colle’s fascia were accessory components. Both diagrams were analyzed for the centeredness, appropriate color usage, bilateral symmetry, and representation of key and accessory components and labelling. Deviation of three accessory components of student images of more than one grid was considered as grossly disproportional diagram. Results: Sequence graphics image scores were significantly more than the scores from projected image tracing (6.04+2.03 vs. 4.72+2.18). The improvement was particularly in terms of symmetry, representation of key and accessory components, labelling and use of appropriate colors. Conclusions: Sequence graphics resulted in drawings with predefined components with labelling. Defining key component and accessory components for moderately difficult diagrams shall result in objective evaluation. Sequence graphics principles aids better drawing skills. Keywords: Artistic anatomy, Medical illustrations, Drawings, Sectional anatomy, Graphics.

Electromagnetic Fields in a Time-Varying Medium: Exceptional Points and Operator Symmetries

In this article, we study the interactions of electromagnetic waves with a non-dispersive dynamic medium that is temporally dependent. Electromagnetic fields under material time-modulation conserve their momentum but not their energy. We assume a time-variation of permittivity, permeability, and conductivity, and derive the appropriate time-domain solutions based on the causality state at a past observation time. We formulate a time-transitioning state matrix and connect the unusual energy transitions of electromagnetic fields in time-varying media with the exceptional point theory. This state-matrix approach allows us to analyze further the electromagnetic waves in terms of parity and time-reversal symmetries and signify parity-time symmetric wave-states without the presence of a spatially symmetric distribution of gain and loss, or any inhomogeneities and material periodicity. This article provides a useful arsenal to study electromagnetic wave phenomena under time-varying media and points out novel physical insights connecting the resulting energy transitions and electromagnetic modes with exceptional point physics and operator symmetries.

Symmetry crossover in layered MPS3 complexes (M=Mn, Fe, Ni) via near-field infrared spectroscopy

Author(s): Neal, SN; Kim, HS; O'Neal, KR; Haglund, AV; Smith, KA; Mandrus, DG; Bechtel, HA; Carr, GL; Haule, K; Vanderbilt, D; Musfeldt, JL | Abstract: We employ synchrotron-based near-field infrared spectroscopy to reveal the vibrational properties of bulk, few-sheet, and single-sheet members of the MPS3 (M=Mn, Fe, Ni) family of materials and compare our findings with complementary lattice dynamics calculations. MnPS3 and the Fe analog are similar in terms of their symmetry crossovers, from C2/m to P3¯1m, as the monolayer is approached. These states differ as to the presence of a C3 rotation around the metal center. On the other hand, NiPS3 does not show a symmetry crossover, and the lack of a Bu symmetry mode near 450 cm-1 suggests that C3 rotational symmetry is already present, even in the bulk material. We discuss these findings in terms of local symmetry and temperature effects as well as the curious relationship between these symmetry transformations and those that take place under pressure.

Coexistence of Multiple Points, Limit Cycles, and Strange Attractors in a Simple Autonomous Hyperjerk Circuit with Hyperbolic Sine Function

In this contribution, a new elegant hyperjerk system with three equilibria and hyperbolic sine nonlinearity is investigated. In contrast to other models of hyperjerk systems where either hidden or self-excited attractors are obtained, the case reported in this work represents a unique one which displays the coexistence of self-excited chaotic attractors and stable fixed points. The dynamic properties of the new system are explored in terms of equilibrium point analyses, symmetry and dissipation, and existence of attractors as well. Common analysis tools (i.e., bifurcation diagram, Lyapunov exponents, and phase portraits) are used to highlight some important phenomena such as period-doubling bifurcation, chaos, periodic windows, and symmetric restoring crises. More interestingly, the system under consideration shows the coexistence of several types of stable states, including the coexistence of two, three, four, six, eight, and ten coexisting attractors. In addition, the system is shown to display antimonotonicity and offset boosting. Laboratory experimental measurements show a very good coherence with the theoretical predictions.

Surgery First and Invisalign System: Combined Digital Approach.

The aim of the present paper is to verify the long-term results in dental and skeletal stability in terms of symmetry, occlusion and functional balance by the association between the IS and the SF technique. In this paper, the authors described 12 cases of severe class III malocclusion treated by the association between the IS and the SF technique. At 1 year of post-orthodontic follow up, the patients present an Angle class I occlusal relationship, no deep bite, no scissor or cross-bite and no open bite. No one patient referred TMJ discomfort nor severe post-surgical complications and no surgical-orthodontic relapse occurred. The surgical and occlusal results are stable in terms of stability in all patients. The results of this study suggest the validity of our protocol in management of class III malocclusion patients.

Rigorous bounds on dynamical response functions and time-translation symmetry breaking

Dynamical response functions are standard tools for probing local physics near the equilibrium. They provide information about relaxation properties after the equilibrium state is weakly perturbed. In this paper we focus on systems which break the assumption of thermalization by exhibiting persistent temporal oscillations. We provide rigorous bounds on the Fourier components of dynamical response functions in terms of extensive or local dynamical symmetries, i.e., extensive or local operators with periodic time dependence. Additionally, we discuss the effects of spatially inhomogeneous dynamical symmetries. The bounds are explicitly implemented on the example of an interacting Floquet system, specifically in the integrable Trotterization of the Heisenberg XXZ model.

A Framework of Modeling Large-Scale Wireless Sensor Networks for Big Data Collection

Large Scale Wireless Sensor Networks (LS-WSNs) are Wireless Sensor Networks (WSNs) composed of an impressive number of sensors, with inherent detection and processing capabilities, to be deployed over large areas of interest. The deployment of a very large number of diverse or similar sensors is certainly a common practice that aims to overcome frequent sensor failures and avoid any human intervention to replace them or recharge their batteries, to ensure the reliability of the network. However, in practice, the complexity of LS-WSNs pose significant challenges to ensuring quality communications in terms of symmetry of radio links and maximizing network life. In recent years, most of the proposed LS-WSN deployment techniques aim either to maximize network connectivity, increase coverage of the area of interest or, of course, extend network life. Few studies have considered the choice of a good LS-WSN deployment strategy as a solution for both connectivity and energy consumption efficiency. In this paper, we designed a LS-WSN as a tool for collecting big data generated by smart cities. The intrinsic characteristics of big data require the use of heterogeneous sensors. Furthermore, in order to build a heterogeneous LS-WSN, our scientific contributions include a model of quantifying the kinds of sensors in the network and the multi-level architecture for LS-WSN deployment, which relies on clustering for the big data collection. The results simulations show that our proposed LS-WSN architecture is better than some well known WSN protocols in the literature including Low Energy Adaptive Clustering Hierarchy (LEACH), E-LEACH, SEP, DEEC, EECDA, DSCHE and BEENISH.

Germanosilicate Cs2In2[(Si2.1Ge0.9)2O15](OH)2 · H2O with a New Corrugated Tetrahedral Layer: Topological Symmetry-Based Prediction of Anionic Radicals

Crystals of a new germanosilicate Cs2In2[(Ge0.4Si0.6)2(Ge0.3Si0.7)2(Ge0.2Si0.8)2O15](OH)2 · H2O were prepared by the hydrothermal synthesis; sp. gr. Pnma, a = 13.3159(3) A, b = 9.2615(2) A, c = 14.9222(4) A. The structure was found to contain a new layered tetrahedral radical. The cores composed of InO6 octahedra are decorated on both sides by (Si,Ge)O4 tetrahedra, which is typical of many layered minerals, for example, of palygorskite and sepiolite. The layers were found to be corrugated due to the presence of large Cs cations in the structure. The principles of formation of anionic radicals are considered. The diversity of anionic radicals is attributed to various symmetrical-topological types of chains and different types of connectedness and arrangement in layers and frameworks in terms of symmetry. Two new hypothetical layers containing four-, six-, and eight-membered rings are predicted based on a deerite chain identified in the layer of the new compound.

Valleytronics in Two-dimensional Materials

A new type of degree of freedom in terms of valley symmetry has recently emerged, allowing an additional control, in addition to the traditional controls of the charge and the spin degrees of freedom, which are widely used in transistors and in spintronic devices, respectively. Valleytronics is a new type of electronics having great potential for faster and more efficient information processing and for high-density data storage in next-generation devices. Two-dimensional materials are considered to be ideal systems for investigating valleytronics due to many systems having two distinguishable valleys of opposite spin textures. In this article, we demonstrate the fundamental properties related to the valley degree of freedom in two-dimensional materials and its potential applications for valleytronic devices.

Costochondral graft in growing patients with hemifacial microsomia case series: Long-term results compared with non-treated patients.

The aim of this study was to evaluate the long-term effectiveness of costochondral graft in hemifacial microsomia (HFM) type III patients. A sample of 10 patients affected by HFM type III treated during growth in the same Centre with costochondral graft (CCG patients group) is compared with a control group (CG) sample of 10 non-treated patients affected by the same malformation in order to understand whether surgery during growth provides advantages in terms of bony and facial symmetry after an 8-year follow-up. The growth of the CCG was assessed on panoramic X-rays. To assess facial symmetry, a photometric evaluation on the frontal view was carried out. In CCG patients group the graft grown in mean less than the healthy ramus, a good facial symmetry was achieved after surgery, but was lost in the majority of the cases at the most recent control. In CG, occlusal canting slightly increased and facial asymmetry was relatively stable during the years. In patients with a congenital deformity, restoring the height of the ramus leads to an immediate restitution of facial symmetry, but in the long term, there is a return to the asymmetrical pattern. In CG, the asymmetry is stable during years with no increase of the facial deformity.

Chiral separation of several pesticides on an immobilized amylose tris(3-chloro-5-methylphenylcarbamate) column under polar-organic conditions. Influence of mobile phase and temperature on enantioselectivity

In this work, the use of different solvents and temperatures was explored, aiming to evaluate their influence on the enantioseparation of pesticides by HPLC in polar-organic conditions, employing a column containing immobilized amylose tris(3-chloro-5-methylphenyl-carbamate). The chiral separation of seventeen different pesticides widely used as herbicides, fungicides, insecticides and precursors were studied. The mobile phases included methanol, ethanol, iso-propanol, n-propanol and acetonitrile; either pure or containing additives such as diethylamine, trifluoroacetic acid, formic acid, acetic acid or mixtures thereof. We studied the influence of these eluents on chiral separation of those pesticides in terms of retention factor, enantioselectivity, enantioresolution and peak symmetry. Regarding temperature influence, evaluated within the range 5 – 40 °C, nearly all the compounds decreased their retention and selectivity factors with the increase in temperature, although the effect was dependent on the mobile phase solvent. Moreover, estimation of thermodynamic parameters was performed based on linear van´t Hoff plots.