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Search Results: 1 - 10 of 4069 matches for " Seung Yeon Ha "
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The Expression of Matrix Metalloproteinases and Tissue Inhibitors of Metalloproteinases in Idiopathic Interstitisal Pneumonia  [PDF]
Ji Young Shin, Yu Jin Kim, Sun Young Kyung, Seung Yeon Ha, Sung Hwan Jeong
Open Journal of Respiratory Diseases (OJRD) , 2014, DOI: 10.4236/ojrd.2014.43014
Background: Idiopathic interstitial pneumonia is characterized by fibroblast proliferation and extracellular matrix (ECM) accumulation. Matrix metalloproteases (MMPs) and tissue inhibitors of metalloproteases (TIMPs) have been shown to regulate remodeling of the ECM, which indicates that they are important factors in the process of lung fibrosis. Therefore, we evaluated the expression of MMPs and TIMPs in tissues obtained from patients with idiopathic interstitial pneumonia and control tissues. Methods: Thirty-seven patients who were diagnosed with IIP (22: IPF, 13: NSIP, 2: COP) and 5 controls were enrolled in this study. The MMP-2 and -9 activity in lung tissue obtained from these patients was analyzed using gelatin zymography and the levels of TIMP-1 and -2 were measured by western blotting. We also evaluated the expression of MMP-2 and -9, as well as that of TIMP-1 and -2 in lung tissue using immunohistochemistry. Results: The levels of MMP-2 and MMP-9 were significantly increased in patients with IPF compared to those with NSIP and COP. The activities of TIMP-1 and -2 were also higher in patients with IPF than NSIP/COP patients and control subjects. There were no significant differences observed in the activities of MMPs and TIMPs obtained from patients with NSIP/COP and control subjects. The immunohistochemical analysis showed that TIMP-2 and MMP-2 were strongly stained at the fibroblasts of the fibroblastic foci in patients with IPF. Conclusions: These results suggest that over-expression of gelatinases and TIMPs in patients with IPF are important factors in the irreversible fibrosis that is associated with lung parenchyma.
Computer Simulation Study of Biopolymer Betanova  [PDF]
Seung-Yeon Kim
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.312002

Betanova is a monomeric, three-stranded antiparallel beta-sheet protein with twenty residues. The pathways between the folded native structure and unfolded conformations of betanova are studied using UNRES force field and the most popular computer simulation method, Metropolis Monte Carlo algorithm. At a fixed temperature, 100 Monte Carlo simulations are performed, starting from the folded native structure, and the pathways are obtained at two different temperatures.

Folding and Unfolding Simulations of a Three-Stranded Beta-Sheet Protein  [PDF]
Seung-Yeon Kim
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.41003

Understanding the folding processes of a protein into its three-dimensional native structure only with its amino-acid sequence information is a long-standing challenge in modern science. Two- hundred independent folding simulations (starting from non-native conformations) and two- hundred independent unfolding simulations (starting from the folded native structure) are performed using the united-residue force field and Metropolis Monte Carlo algorithm for betanova (three-stranded antiparallel beta-sheet protein). From these extensive computer simulations, two representative folding pathways and two representative unfolding pathways are obtained in the reaction coordinates such as the fraction of native contacts, the radius of gyration, and the root- mean-square deviation. The folding pathways and the unfolding pathways are similar each other. The largest deviation between the folding pathways and the unfolding pathways results from the root-mean-square deviation near the folded native structure. In general, unfolding computer simulations could capture the essentials of folding simulations.

Efficacy and Safety of Low Target Pressure Trabeculectomy: 2-Year Clinical Results  [PDF]
Seung Joo Ha
Open Journal of Ophthalmology (OJOph) , 2018, DOI: 10.4236/ojoph.2018.81007
Purpose: To compare the success and complication rates of low target pressure trabeculectomy (LTT) and conventional trabeculectomy (CT). Methods: A retrospective study was conducted with consecutive patients undergoing trabeculectomy. Twelve eyes of 12 patients underwent LTT, and 17 eyes of 17 patients underwent CT. Surgical success was defined as meeting each target intraocular pressure (IOP) without additional medication or further glaucoma surgery. A Kaplan-Meier survival analysis was used to estimate survival rate. Incidences of surgical complications were also assessed. Results: The median postoperative IOP 2 years after surgery were 10.0 mmHg (interquartile range [IQR] 8.5 - 12.0 mmHg) in the LTT group and 16.0 mmHg (IQR, 14.0 - 18.5 mmHg) in the CT group (P = 0.000). Estimated survival rates for patients who underwent the two types of trabeculectomy were significantly different with all IOP criteria of 10, 12 and 14 mmHg (P < 0.01 for all), except IOP ≤ 18 mmHg. Vision-threatening complications were not found in either group during the observation period. Late-onset bleb leaks occurred in only two eyes in the LTT group but were well treated with autologous blood injection and amniotic membrane transplantation. Conclusion: LTT provided more chances to maintain low postoperative IOP and had no more vision-threatening complication than those of CT.
Fisher zeros and Potts zeros of the Q-state Potts model for nonzero external magnetic field
Seung-Yeon Kim
Physics , 2003,
Abstract: The properties of the partition function zeros in the complex temperature plane (Fisher zeros) and in the complex $Q$ plane (Potts zeros) are investigated for the $Q$-state Potts model in an arbitrary nonzero external magnetic field $H_q$, using the exact partition function of the one-dimensional model.
Density of Yang-Lee zeros for the Ising ferromagnet
Seung-Yeon Kim
Physics , 2006, DOI: 10.1103/PhysRevE.74.011119
Abstract: The densities of Yang-Lee zeros for the Ising ferromagnet on the $L\times L$ square lattice are evaluated from the exact grand partition functions ($L=3\sim16$). The properties of the density of Yang-Lee zeros are discussed as a function of temperature $T$ and system size $L$. The three different classes of phase transitions for the Ising ferromagnet, first-order phase transition, second-order phase transition, and Yang-Lee edge singularity, are clearly distinguished by estimating the magnetic scaling exponent $y_h$ from the densities of zeros for finite-size systems. The divergence of the density of zeros at Yang-Lee edge in high temperatures (Yang-Lee edge singularity), which has been detected only by the series expansion until now for the square-lattice Ising ferromagnet, is obtained from the finite-size data. The identification of the orders of phase transitions in small systems is also discussed using the density of Yang-Lee zeros.
Yang-Lee zeros of the one-dimensional Q-state Potts model
Seung-Yeon Kim
Physics , 2003, DOI: 10.3938/jkps.44.495
Abstract: The distributions of the Yang-Lee zeros of the ferromagnetic and antiferromagnetic Q-state Potts models in one dimension are studied for arbitrary Q and temperature. The Yang-Lee zeros of the Potts antiferromagnet have been fully investigated for the first time. The distributions of the Yang-Lee zeros show a variety of different shapes. Some of the Yang-Lee zeros lie on the positive real axis even for T>0. For the ferromagnetic model this happens only for Q<1, while there exist some zeros of the antiferromagnetic model on the positive real axis both for Q<1 and for Q>1.
Partition function zeros of the Q-state Potts model on the simple-cubic lattice
Seung-Yeon Kim
Physics , 2002, DOI: 10.1016/S0550-3213(02)00465-0
Abstract: The $Q$-state Potts model on the simple-cubic lattice is studied using the zeros of the exact partition function on a finite lattice. The critical behavior of the model in the ferromagnetic and antiferromagnetic phases is discussed based on the distribution of the zeros in the complex temperature plane. The characteristic exponents at complex-temperature singularities, which coexist with the physical critical points in the complex temperature plane for no magnetic field ($H_q=0$), are estimated using the low-temperature series expansion. We also study the partition function zeros of the Potts model for nonzero magnetic field. For $H_q>0$ the physical critical points disappear and the Fisher edge singularities appear in the complex temperature plane. The characteristic exponents at the Fisher edge singularities are calculated using the high-field, low-temperature series expansion. It seems that the Fisher edge singularity is related to the Yang-Lee edge singularity which appears in the complex magnetic-field plane for $T>T_c$.
Analgesic effect of highly reversible ω-conotoxin FVIA on N-type Ca2+ channels
Seungkyu Lee, Yoonji Kim, Seung Keun Back, Hee-Woo Choi, Ju Yeon Lee, Hyun Ho Jung, Jae Ha Ryu, Hong-Won Suh, Heung Sik Na, Hyun Jeong Kim, Hyewhon Rhim, Jae Il Kim
Molecular Pain , 2010, DOI: 10.1186/1744-8069-6-97
Abstract: Here we identify a new CTx, FVIA, from the Korean Conus Fulmen and describe its effects on pain responses and blood pressure. The inhibitory effect of CTx-FVIA on N-type Ca2+ channel currents was dose-dependent and similar to that of CTx-MVIIA. However, the two conopeptides exhibited markedly different degrees of reversibility after block. CTx-FVIA effectively and dose-dependently reduced nociceptive behavior in the formalin test and in neuropathic pain models, and reduced mechanical and thermal allodynia in the tail nerve injury rat model. CTx-FVIA (10 ng) also showed significant analgesic effects on writhing in mouse neurotransmitter- and cytokine-induced pain models, though it had no effect on acute thermal pain and interferon-γ induced pain. Interestingly, although both CTx-FVIA and CTx-MVIIA depressed arterial blood pressure immediately after administration, pressure recovered faster and to a greater degree after CTx-FVIA administration.The analgesic potency of CTx-FVIA and its greater reversibility could represent advantages over CTx-MVIIA for the treatment of refractory pain and contribute to the design of an analgesic with high potency and low side effects.Voltage-gated Ca2+ channels (VGCC) play an important role in the transmission of pain signals from peripheral nerves to the brain [1-3]. Of several types of VGCC, the N-type Ca2+ channel is particularly important for perception of chronic nociceptive pain, as its blockade at the spinal cord and sensory neurons inhibits stimulus-evoked release of pain-inducing peptides, such as substance P, and excitatory neurotransmitters, such as glutamate [4]. It is well known that various peptide toxins from animal venom alleviate pain by specifically binding to N-type Ca2+ channels with high affinity [5]. For example, several ω-conotoxins (CTxs), including GVIA, MVIIA, CVID and SO-3, exert apparent analgesic effects against both inflammatory and neuropathic pain [6-8].Ziconotide (CTx-MVIIA; Prialt?) is the first CTx-de
Preclinical Evidence of Rapid-Onset Antidepressant-Like Effect in Radix Polygalae Extract
Im-Joon Shin, Sung Un Son, Hyunwoo Park, Yoorim Kim, Sung Hyun Park, Kelley Swanberg, Joo-Yeon Shin, Sang-Kyu Ha, Yoonju Cho, Soo-Yong Bang, Jae-Hwan Lew, Seung-Hun Cho, Sungho Maeng
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088617
Abstract: Radix Polygalae (the root of Polygala tenuifolia) is a herb widely used in traditional Asian medicine that is thought to exert a variety of neuropsychiatric effects. Radix Polygalae extract can protect against N-methyl D-aspartate (NMDA) neurotoxicity and induce brain-derived neurotrophic factor (BDNF) expression, suggesting modulatory roles at glutamatergic synapses and possible antidepressant action. In accordance with this hypothesis, Radix Polygalae extract demonstrated antidepressant-like effects in 8-week-old male C57Bl/6 mice by decreasing behavioral despair in the forced swim and tail suspension tasks and increasing hedonic-like behavior in the female urine sniffing test 30 minutes after a single oral administration of 0.1 mg/kg. Reduced latency to acquire a food pellet in the novely suppressed feeding paradigm, without change in anxiety-like behaviors suggested a rapid-onset nature of the antidepressant-like effect. In addition, it decreased the number of failed escapes in the learned helplessness paradigm after two oral administrations 24 hours and 30 minutes before the first test. Finally, it reversed anhedonia as measured by saccharin preference in mice exposed to the chronic stress model after two administrations of 0.1 mg/kg, in contrast to the repeated administration generally needed for similar effect by monoamergic antidepressants. Immobility reduction in tail suspension task was blocked by the α-amino-3-hydroxy-5-methyl-4-isoxazolepr?opionicacid (AMPA) receptor antagonist NBQX, a pattern previously demonstrated by ketamine and other ketamine-like rapid-onset antidepressants. Also similarly to ketamine, Radix Polygalae appeared to acutely decrease phosphorylation of GluR1 serine-845 in the hippocampus while leaving the phosphorylation of hippocampal mTOR serine 2448 unchanged. These findings serve as preclinical evidence that Radix Polygalae extract exerts rapid-onset antidepressant effects by modulating glutamatergic synapses in critical brain circuits of depression and may be worthy of further evaluation as a safe substitute to other rapid-onset antidepressants known to have unacceptable side effects.
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