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# Symmetry

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#1
Oliver A Kannape, Hugh M Herr, Oliver A Kannape, Hugh M Herr, Oliver A Kannape, Hugh M Herr
Our ability to automatically adapt our walking pattern to the demands of our environment is central to maintaining a steady gait. Accordingly, a large effort is being made to extend and integrate this adaptability to lower-limb prostheses. To date, the main focus of this research has been on short term adaptation, such as in response to a terrain transition or a sudden change in the environment. However, long term adaptation and underlying sensorimotor learning processes are critical to optimizing walking patterns and predictively changing our gait when faced with continued perturbations...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#2
Subrahmanyam Gorthi, Subrahmanyam Gorthi, Subrahmanyam Gorthi
Normal human brain exhibits approximately bi-fold symmetry with respect to its midsagittal plane (MSP). The objective of this work is to investigate the effect of doubling atlases (i.e., reference images) used in multi-atlas fusion methods by exploiting the inherent bilateral symmetry of human brain. To this end, we perform automated segmentation of 15 subcortical structures using Local Weighted Voting (LWV) fusion method with varying number of atlases. We consider three specific scenarios for atlases while performing fusion: (i) fusion with original OASIS atlases, (ii) with atlases obtained by flipping the original atlases based on their MSP, and (iii) with both original and flipped atlases...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#3
Nan Xu, Peter C Doerschuk, Nan Xu, Peter C Doerschuk, Nan Xu, Peter C Doerschuk
Stochastic models of nano-biomachines have been studied by 3-D reconstruction from cryo electron microscopy images in recent years. The image data is the projection of many heterogeneous instances of the object under study (e.g., a virus). Initial reconstruction algorithms require different instances of the object, while still heterogeneous, to have the same symmetry. This paper presents a maximum likelihood reconstruction approach which allows each object to lack symmetry while constraining the statistics of the ensemble of objects to have symmetry...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#4
Ilija Uzelac, Conner Herndon, James Farmer, Flavio Fenton, Ilija Uzelac, Conner Herndon, James Farmer, Flavio Fenton, Ilija Uzelac, Conner Herndon, James Farmer, Flavio Fenton
Electrocardiogram recordings during opucal mapping experiments in heart tissue are commonly used tu monitor the health of the preparation and to obtain dominant frequencies during arrhythmic and defibrillatory studies. However the use of ECG reconstructed from optical mapping is seldom used and to date it has not been strictly validated. In this manuscript we present the first detailed validation and comparison of Optical Mapping ECG, or OM-ECG, with standard ECG recordings by calculating the electrostatic potential in space as a function of the voltage measured optically and describe the different approximations that can be used to obtain unipolar or bipolar ECG recordings...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#5
Tyagi Ramakrishnan, Haris Muratagic, Kyle B Reed, Tyagi Ramakrishnan, Haris Muratagic, Kyle B Reed, Kyle B Reed, Tyagi Ramakrishnan, Haris Muratagic
People with physical impairments often have asymmetric gait. To evaluate if their overall symmetry is improving during intervention, there needs to be a simple metric that can help classify gait patterns that includes multiple measures of gait asymmetry. The Combined Gait Asymmetry Metric presented here is based on the Mahalanobis distance of multiple step parameters. We tested able-bodied subjects with perturbations that involve a change in leg length, the addition of ankle weights, and a combination of both perturbations...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#6
Andre V Pigatto, Karina O A Moura, Gabriela W Favieiro, Alexandre Balbinot, Andre V Pigatto, Karina O A Moura, Gabriela W Favieiro, Alexandre Balbinot, Karina O A Moura, Gabriela W Favieiro, Alexandre Balbinot, Andre V Pigatto
This report describes the development of a force platform based on instrumented load cells with built-in conditioning circuit and strain gages to measure and acquire the components of the force that is applied to the bike crank arm during pedaling in real conditions, and save them on a SD Card. To accomplish that, a complete new crank arm 3D solid model was developed in the SolidWorks, with dimensions equivalent to a commercial crank set and compatible with a conventional road bike, but with a compartment to support all the electronics necessary to measure 3 components of the force applied to the pedal during pedaling...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#7
Yinan Li, Babak Fahimi, Yinan Li, Babak Fahimi, Babak Fahimi, Yinan Li
Infrared thermography (IRT), or thermal imaging has long been proposed as a novel method in early detection of breast cancer. Most of the work done was through the detection of abnormal hotspot, or asymmetries in a thermal texture map. However, the surface temperature may not appear symmetric even for a healthy breast because of variations in blood supply and individual differences. In this paper, a method that is independent of the aforementioned symmetry is proposed. The breast under detection is initially excited by a group of patch antennas...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#8
Dongxia Zhang, Yangzhou Gan, Zeyang Xia, Xinwen Zhou, Shoubin Liu, Jing Xiong, Guanglin Li, Dongxia Zhang, Yangzhou Gan, Zeyang Xia, Xinwen Zhou, Shoubin Liu, Jing Xiong, Guanglin Li, Zeyang Xia, Shoubin Liu, Xinwen Zhou, Dongxia Zhang, Yangzhou Gan, Guanglin Li, Jing Xiong
Estimation of tooth axis is needed for some clinical dental treatment. Existing methods require to segment the tooth volume from Computed Tomography (CT) images, and then estimate the axis from the tooth volume. However, they may fail during estimating molar axis due to that the tooth segmentation from CT images is challenging and current segmentation methods may get poor segmentation results especially for these molars with angle which will result in the failure of axis estimation. To resolve this problem, this paper proposes a new method for molar axis estimation from CT images...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#9
In this study, we used a model-based approach to explore the potential contributions of central pattern generating circuits (CPGs) during adaptation to external perturbations during locomotion. We constructed a neuromechanical modeled of locomotion using a reduced-phase CPG controller and an inverted pendulum mechanical model. Two different forms of locomotor adaptation were examined in this study: split-belt treadmill adaptation and adaptation to a unilateral, elastic force field. For each simulation, we first examined the effects of phase resetting and varying the model's initial conditions on the resulting adaptation...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
#10
Ruchin G Patel
The nose is a complex structure important in facial aesthetics and in respiratory physiology. Nasal defects can pose a challenge to reconstructive surgeons who must re-create nasal symmetry while maintaining nasal function. A basic understanding of the underlying nasal anatomy is thus necessary for successful nasal reconstruction.
February 2017: Facial Plastic Surgery: FPS
#11
Feiyun Long, Haitao Liu, Dafang Li, Jun Yan
With the help of density functional theory, a series of matryoshka superatoms $\rm{X@Y_{12}@X_{20}}$ (X=Ge, Y=Zn; X=Sn, Y=Mg, Mn, Zn or Cd; X=Pb, Y= Mg, Mn, Cd or Hg) with icosahedral symmetry has been extensively studied, to focus on the influence of the spin-orbit coupling on geometries, stabilities, electronic structures and magnetic moments for these clusters. Generally speaking, the effect of spin-orbit coupling is highly correlated with composition elements of these clusters. $\rm{Ge@Zn_{12}@Ge_{20}}$ is little affected by the spin-orbit coupling, while clusters containing Sn atom will generally undergo a moderate influence on their atomization energy, HOMO-LUMO gap and projected density of states...
February 22, 2017: Journal of Physical Chemistry. A
#12
Serena Corallini, Monica Ceretti, Alain Cousson, Clemens Ritter, Marco Longhin, Philippe Papet, Werner Paulus
Oxygen-deficient Sr2ScGaO5 single crystals with a cubic perovskite structure were grown by the floating-zone technique. The transparent crystals of this pure 3D oxygen electrolyte are metastable at ambient temperature, showing one-sixth of all oxygen positions vacant. While neutron single-crystal diffraction, followed by maximum entropy analysis, revealed a strong anharmonic displacements for the oxygen atoms, a predominant formation of ScO6 octahedra and GaO4 tetrahedra is indicated by Raman spectroscopic studies, resulting in a complex oxygen defect structure with short-range order...
February 22, 2017: Inorganic Chemistry
#13
Michel Rickhaus, Marcel Mayor, Michal Juríček
Carbon allotropes constituted of sp(2)-hybridised carbon atoms display a variety of properties that arise from their delocalised π-conjugated electronic structure. Apart from carbon's planar allotropic form graphene, bent or curved structures, such as carbon nanotubes or fullerenes, respectively, have been discovered. In this Tutorial Review, we analyse and conceptually categorise chiral synthetic molecular fragments of non-planar sp(2)-carbon allotropes, including hypothetical forms of carbon that have been proposed to exist as stable entities...
February 22, 2017: Chemical Society Reviews
#14
László Deák, László Bottyán, Tamás Fülöp, Dániel Géza Merkel, Dénes Lajos Nagy, Szilárd Sajti, Kai Sven Schulze, Hartmut Spiering, Ingo Uschmann, Hans-Christian Wille
Reciprocity is when wave or quantum scattering satisfies a symmetry property, connecting a scattering process with the reversed one. While reciprocity involves the interchange of source and detector, it is fundamentally different from rotational invariance, and is a generalization of time reversal invariance, occurring in absorptive media as well. Due to its presence at diverse areas of physics, it admits a wide variety of applications. For polarization dependent scatterings, reciprocity is often violated, but violation in the phase of the scattering amplitude is much harder to experimentally observe than violation in magnitude...
February 22, 2017: Scientific Reports
#15
Amelia J H Arundale, Kathleen Cummer, Jacob J Capin, Ryan Zarzycki, Lynn Snyder-Mackler
BACKGROUND: Athletes often are cleared to return to activities 6 months after anterior cruciate ligament (ACL) reconstruction; however, knee function measures continue to improve up to 2 years after surgery. Interventions beyond standard care may facilitate successful return to preinjury activities and improve functional outcomes. Perturbation training has been used in nonoperative ACL injury and preoperative ACL reconstruction rehabilitation, but has not been examined in postoperative ACL reconstruction rehabilitation, specifically return to sport rehabilitation...
February 21, 2017: Clinical Orthopaedics and related Research
#16
Jacob John Capin, Ryan Zarzycki, Amelia Arundale, Kathleen Cummer, Lynn Snyder-Mackler
BACKGROUND: Movement asymmetries during walking are common after anterior cruciate ligament (ACL) injury and reconstruction and may influence the early development of posttraumatic osteoarthritis. Preoperative neuromuscular training (like perturbation training, which is neuromuscular training requiring selective muscle activation in response to surface perturbations) improves gait asymmetries and functional outcomes among people who are ACL-deficient, but the effect of postoperative perturbation training on gait mechanics after ACL reconstruction is unknown...
February 21, 2017: Clinical Orthopaedics and related Research
#17
Syed Baker, Azmath Pasha, Sreedharamurthy Satish
The present study emphasizes on synthesis of bimetallic silver-gold nanoparticles from cell free supernatant of Pseudomonas veronii strain AS41G inhabiting Annona squamosa L. The synthesized nanoparticles were characterized using hyphenated techniques with UV-Visible spectra ascertained absorbance peak between 400 and 800 nm. Possible interaction of biomolecules in mediating and stabilization of nanoparticles was depicted with Fourier transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) displayed Bragg's peak conferring the 1 0 0, 1 1 1, 2 0 0, and 2 2 0 facets of the face centered cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature...
January 2017: Saudi Pharmaceutical Journal: SPJ: the Official Publication of the Saudi Pharmaceutical Society
#18
Jamie Weaver, Chuck Z Soderquist, Nancy M Washton, Andrew S Lipton, Paul L Gassman, Wayne W Lukens, Albert A Kruger, Nathalie A Wall, John S McCloy
Insight into the solid-state chemistry of pure technetium-99 ((99)Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorption spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction...
February 21, 2017: Inorganic Chemistry
#19
Oleksandr Stetsovych, Martin Švec, Jaroslav Vacek, Jana Vacek Chocholoušová, Andrej Jančařík, Jiří Rybáček, Krzysztof Kosmider, Irena G Stará, Pavel Jelínek, Ivo Starý
The chirality of molecular structures is paramount in many phenomena, including enantioselective reactions, molecular self-assembly, biological processes and light or electron-spin polarization. Flat prochiral molecules, which are achiral in the gas phase or solution, can exhibit adsorption-induced chirality when deposited on surfaces. The whole array of such molecular adsorbates is naturally racemic as spontaneous global mirror-symmetry breaking is disfavoured. Here we demonstrate a chemical method of obtaining flat prochiral molecules adsorbed on the solid achiral surface in such a way that a specific adsorbate handedness globally dominates...
March 2017: Nature Chemistry
#20
Jarret T Crawford, Mark J Brandt, Yoel Inbar, John R Chambers, Matt Motyl
Liberals and conservatives both express prejudice toward ideologically dissimilar others (Brandt et al., 2014). Previous work on ideological prejudice did not take advantage of evidence showing that ideology is multidimensional, with social and economic ideologies representing related but separable belief systems. In 5 studies (total N = 4912), we test 3 competing hypotheses of a multidimensional account of ideological prejudice. The dimension-specific symmetry hypothesis predicts that social and economic ideologies differentially predict prejudice against targets who are perceived to vary on the social and economic political dimensions, respectively...
March 2017: Journal of Personality and Social Psychology
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