• Title/Summary/Keyword: non-symmetry

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Effects of Real-time Visual Feedback Gait Training on Gait Stability in Older Adults (실시간 시각적 피드백 보행 훈련이 노인들의 보행 안정성에 미치는 영향)

  • Byun, Kyungseok;Han, Sooji;Bhang, Dawon;Seo, Hyundam;Lee, Hyo Keun
    • Korean Journal of Applied Biomechanics
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    • v.30 no.3
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    • pp.247-253
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    • 2020
  • Objective: This study aimed to examine the effects of real-time visual feedback gait training on gait stability in older adults. Method: Twelve older adults participated in this study, being divided into 2 groups including a) visual feedback (VF) and b) non-visual feedback (NVF) groups. For 4 weeks, VF performed a treadmill walking training with real-time visual feedback about their postural information while NVF performed a normal treadmill walking training. For evaluations of gait stability, kinematic data of 15-minute treadmill walking were collected from depth-based motion capture system (30 Hz, exbody, Korea). Given that step lengths in both right and left sides were determined based on kinematic data, three variables including step difference, coefficient of variation, approximate entropy were calculated to evaluate gait symmetry, variability and complexity, respectively. Results: For research findings, VF exhibited significant improvements in gait stability after 4-week training in comparison to NVF, particularly in gait symmetry and complexity measures. However, greater improvement in gait variability was observed in NVF than VF. Conclusion: Given that visual feedback walking gives potential effectiveness on gait stability in older adults, gait training with visual feedback may be a robust therapeutic intervention in people with gait disturbances like instability or falls.

Strategies to Design Efficient Donor-Acceptor (D-A) Type Emitting Molecules: Molecular Symmetry and Electron Accepting Ability of D-A Type Molecules

  • Hyun Gi Kim;Young-Seok Baek;Sung Soo Kim;Sang Hyun Paek;Young Chul Kim
    • Applied Chemistry for Engineering
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    • v.34 no.6
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    • pp.633-639
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    • 2023
  • We synthesized 2-(10-methyl-10H-phenothiazin-3-yl)-5-phenyl-1,3,4-oxadiazole (MPPO) and 5,5-(10-methyl-10H-phenothiazin-3,7-diyl)-bis-(2-phenyl-1,3,4-oxadiazole) (DPPO). MPPO has both electron-donating and electron-accepting substituents with asymmetric molecular geometry. By incorporating one extra electron-accepting group into MPPO, we created a symmetric molecule, which is DPPO. The optical and electrochemical properties of these compounds were measured. The lowest unoccupied molecular orbital (LUMO) level of DPPO was lower than that of MPPO. The excited-state dipole moment of DPPO, with symmetric geometry, was calculated to be 4.1 Debye, whereas MPPO, with asymmetric geometry, had a value of 7.0 Debye. The charge-carrier mobility of both compounds was similar. We fabricated non-doped organic light-emitting diodes (OLEDs) using D-A type molecules as an emitting layer. The current efficiency of the DPPO-based device was 7.8 cd/A, and the external quantum efficiency was 2.4% at 100 cd/m2, demonstrating significantly improved performance compared to the MPPO-based device. The photophysical and electroluminescence (EL) characteristics of the two D-A type molecules showed that molecular symmetry, as well as the lowered LUMO level of DPPO, played critical roles in the enhancement of EL performance.

A Study on the Vibration Characteristics of Symmetry, Asymmetry Laminated Composite Materials by using Time-Average ESPI (시간평균 ESPI를 이용한 대칭.비대칭 적층 복합재료의 진동 특성 비교에 관한 연구)

  • Hong Kyung-Min;Ryu Weon-Jae;Kang Young-Jung;Kang Shin-Jae
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.259-260
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    • 2006
  • The ESPI(Electronic Speckle Pattern Interferometry) is a real time, full-field, non-destructive optical measurement technique. In this study, ESPI is proposed for the purpose of vibration analysis for new material, composite material. Composite materials have various complicated characteristics according to the ply materials, ply orientations, ply stacking sequences and boundary conditions. Therefore, it is difficult to analysis composite materials. For efficient use of composite materials in engineering applications the dynamic behavior, that is, natural frequencies, nodal patterns should be informed. If use Time-Average ESPI, can analyze vibration characteristic of composite material by real time easily. This study manufactured laminated composite of symmetry, asymmetry two kinds that is consisted of CFRP(Carbon Fiber Reinforced Plastics) and shape of test piece is rectangular form.

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Characteristics of Flow past a Sphere in Uniform Shear (균일 전단유동 내에 위치한 구 주위의 유동특성)

  • Kim, Dong-Joo;Choi, Hyung-Seok;Choi, Hae-Cheon
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1607-1612
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    • 2004
  • Numerical simulations are performed to investigate the characteristics of flow past a sphere in uniform shear. The Reynolds numbers considered are Re=300, 425 and 480 based on the inlet center velocity and sphere diameter. The non-dimensional shear rate K of the inlet uniform shear is varied from 0 to 0.15. At Re=300, the head of the hairpin vortex loop always locates on the high-velocity side in uniform shear, and the flow maintains the planar symmetry. At Re=425 and 480, the irregularity in the location and strength of the hairpin vortex appearing in uniform inlet flow is much reduced in uniform shear, but the flows still keep the asymmetry for most inlet shear rates. However, in the cases of K=0.075 and 0.1 at Re=425, the flows become planar symmetric and their characteristics of the evolution of the hairpin vortex loops are different from those of asymmetric flows. A hysteresis phenomenon switching from the planar symmetry to the asymmetry (or vice versa) depending on the initial condition is also observed at Re=425.

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The Crystal Structure of L-Leucine Dehydrogenase from Pseudomonas aeruginosa

  • Kim, Seheon;Koh, Seri;Kang, Wonchull;Yang, Jin Kuk
    • Molecules and Cells
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    • v.45 no.7
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    • pp.495-501
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    • 2022
  • Leucine dehydrogenase (LDH, EC 1.4.1.9) catalyzes the reversible deamination of branched-chain L-amino acids to their corresponding keto acids using NAD+ as a cofactor. LDH generally adopts an octameric structure with D4 symmetry, generating a molecular mass of approximately 400 kDa. Here, the crystal structure of the LDH from Pseudomonas aeruginosa (Pa-LDH) was determined at 2.5 Å resolution. Interestingly, the crystal structure shows that the enzyme exists as a dimer with C2 symmetry in a crystal lattice. The dimeric structure was also observed in solution using multiangle light scattering coupled with size-exclusion chromatography. The enzyme assay revealed that the specific activity was maximal at 60℃ and pH 8.5. The kinetic parameters for three different amino acid and the cofactor (NAD+) were determined. The crystal structure represents that the subunit has more compact structure than homologs' structure. In addition, the crystal structure along with sequence alignments indicates a set of non-conserved arginine residues which are important in stability. Subsequent mutation analysis for those residues revealed that the enzyme activity reduced to one third of the wild type. These results provide structural and biochemical insights for its future studies on its application for industrial purposes.

Effects of Ankle Control Training Using Neuromuscular Electrical Stimulation on Leg Muscle Activation and Balance in Patients with Stroke

  • Soo-Yong Lee;Hyo-Jung Park;Yu-Sik Choi
    • The Journal of Korean Physical Therapy
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    • v.35 no.5
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    • pp.145-150
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    • 2023
  • Purpose: This study examined the effects of ankle control training using neuromuscular electrical stimulation (NMES), leg muscle activation, and balance in stroke patients. Methods: Thirty-one stroke patients diagnosed with cerebral infarction and cerebral hemorrhage were selected for the study. The experimental group underwent ankle control training using NMES, while the control group applied NMES to the paretic tibialis anterior muscle for 30 minutes per session, five times a week for four weeks. The muscle activity changes were measured using surface electromyography, and balance parameters were evaluated using a functional reach test (FRT). Results: The intra-group comparison of the concentric muscle activity revealed improvements in the experimental group, including paretic tibialis anterior (TA) muscle (p<0.05), medial gastrocnemius muscle (MG) (p<0.01), and lateral gastrocnemius muscle (LG) (p<0.05), as well as MG (p<0.05), LG (p<0.05), soleus muscle (p<0.05) of the non-paretic side, and soleus muscle symmetry index (p<0.05). The intra-group comparison of the eccentric muscle activity showed improvements in the experimental group, including MG (p<0.01) and LG (p<0.01) of the paretic side, as well as MG (p<0.01), LG (p<0.01) of the non-paretic side, and LG symmetry index (p<0.01). The intra-group comparison of the functional reach test revealed significant differences in the test results in the experimental and control groups (p<0.05). Conclusion: Ankle control training using NMES had a positive effect on the changes in muscle activation and improved balance in patients with stroke.

PRIMORDIAL BLACKHOLE AS A SEED FOR THE COSMIC MAGNETIC FIELD

  • LA DAIL;PARK CHANGBOM
    • Journal of The Korean Astronomical Society
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    • v.29 no.2
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    • pp.83-91
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    • 1996
  • We present a model that rotating primordial blackholes(PBHs) produced at the end of inflation generate the random, non-oriented primordial magnetic field. PBHs are copiously produced as the Universe completes the cosmic phase transition via bubble nucleation and tunneling processes in the extended inflation hypothesis. The PBHs produced acquire angular momentum through the mutual tidal gravitational interaction. For PBHs of mass less than 1013g, one can show that the evaporation (photon) luminosity of PBHs exceeds the Eddington limit. Thus throughout the lifetime of the rotating PBH, radiation flow from the central blackhole along the Kerr-geodesic exerts torque to ambient plasma. In the process similar to the Bierman's battery mechanism electron current reaching up to the horizon scale is induced. For PBHs of Grand Unified Theories extended inflation with the symmetry breaking temperature of $T_{GUT}\;\~\;10^{10}$ GeV, which evaporate near decoupling, we find that they generate random, non-oriented magnetic fields of $\~10^{-11}G$ on the last-scattering surface on (the present comoving) scales of $\~O(10)Mpc$.

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Solution of Eigenproblems for Non-proportional Damping Systems by Lanczos Method (Lanczos 방법에 의한 비비례 감쇠 시스템의 고유치 해석)

  • 김만철;정형조;오주원;이인원
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.283-290
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    • 1998
  • A solution method is presented to solve the eigenproblem arising in tile dynamic analysis of non-proportional damping systems with symmetric matrices. The method is based on tile use of Lanczos method to generate a Krylov subspace of trial vectors, witch is then used to reduce a large eigenvalue problem to a much smaller one. The method retains the η order quadratic eigenproblem, without the need to the method of matrix augmentation traditionally used to cast the problem as a linear eigenproblem of order 2n. In the process, the method preserves tile sparseness and symmetry of the system matrices and does not invoke complex arithmetics, therefore, making it very economical for use in solving large problems. Numerical results are presented to demonstrate the efficiency and accuracy of the method.

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MONTE-CARLO SIMULATION OF NEUTRON STAR ORBITS IN THE GALAXY

  • TAANI, ALI
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.583-584
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    • 2015
  • In this paper, the numerical results concerning different orbits of a 3D axisymmetric non-rotating galactic potential are presented. We use $Paczy{\acute{n}}ski^{\prime}s$ gravitational potential with different birth velocity distributions for the isolated old Neutron Star (NS) population. We note some smooth non-constant segments corresponding to regular orbits as well as the characterization of their chaoticity. This is strongly related to the effect of different kick velocities due to supernovae mass-loss and natal kicks to the newly-formed NS. We further confirm that the dynamical motion of the isolated old NSs in the gravitational field becomes obvious, with some significant diffraction in the symmetry of their orbital characteristics.

The Crystal Structure of Fenbufen, 3-(4-biphenylylcarbonyl)propionic acid ($C_{16}H_{14}O_3$), A Non-steroidal Antiinflammatory Agent

  • Kim, Yang-Bae;Park, Il-Yeong;Park, Yang-Hwan
    • Archives of Pharmacal Research
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    • v.11 no.2
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    • pp.127-133
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    • 1988
  • The crystal structure of fenbufen was determined by X-ray diffraction techniuques. The compound was recrystallized in orthorhombic crystal system, space group $Pca2_1$ a = 31. 918(10), b = 5.550 (2), c = 15.078 (9) ${\AA}, D_m$= $1.26, {\D_x$= 1.264 g/$\textrm{cm}^3$, and Z = 8. The structure was solved by direct methods and refined by least squares procedure to the final R value of 0.051 for 1780 independent reflections. Two molecules in the asymmetric unit are related by a pseudo center of symmetry and dimerized via O-H...O hydrogen bonds. The carbonyl group attached to the phenyl ring is nearly coplanar to the ring. In the crystal the molecules are arranged in paralle stacks in the a direction.

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