Publications by authors named "Hyun Duk Yang"

Alzheimer's disease (AD) is the most serious age-related neurodegenerative disease and causes destructive and irreversible cognitive decline. Failures in the development of therapeutics targeting amyloid-β (Aβ) and tau, principal proteins inducing pathology in AD, suggest a paradigm shift towards the development of new therapeutic targets. The gram-negative bacteria and lipopolysaccharides (LPS) are attractive new targets for AD treatment.

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SiO is a commonly used insulation layer for QCLs but has high absorption peak around 8 to 10 µm. Instead of SiO, we used YO as an insulation layer for DC-QCL and successfully demonstrated lasing operation at the wavelength around 8.1 µm.

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As modern society ages rapidly, the number of people with dementia is sharply increasing. Direct medical costs and indirect social costs for dementia patients are also increasing exponentially. However, the lack of social awareness about dementia results in difficulties to dementia patients and their families.

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Si-based integrated circuits have been intensively developed over the past several decades through ultimate device scaling. However, the Si technology has reached the physical limitations of the scaling. These limitations have fuelled the search for alternative active materials (for transistors) and the introduction of optical interconnects (called "Si photonics").

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We fabricated interdigitated germanium (Ge) metal-semiconductor-metal photodetectors (MSM PDs) with interdigitated platinum (Pt) finger electrodes and investigated the effects of Pt finger width and spacing on their spectral response. An increase in the incident optical power enhances the creation of electron-hole pairs, resulting in a significant increase in photo current. Lowering of the Schottky barrier could be a main cause of the increase in both photo and dark current with increasing applied bias.

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Alzheimer's disease (AD) is the most common cause of memory impairment and dementia in the elderly. AD is pathologically characterized by extracellular deposits of beta-amyloid (Aβ) peptide, neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau, neuronal loss, and neurotransmitter dysfunction. Clinically, AD is characterized by progressive cognitive decline that usually starts with memory impairment and progresses to cause a more generalized cognitive dysfunction, behavioral dysregulation, and neuropsychiatric symptoms.

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Background: The main complication of cerebral cavernous angioma is hemorrhage. Ischemic stroke as a complication of cerebral cavernous angioma has rarely been described, and hemorrhage after ischemic Wallenberg's syndrome has not been reported before.

Case Report: A 45-year-old woman presented with perioral numbness, hoarseness, dysphagia, and worsening of her previous sensory symptoms.

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The accumulation of beta-amyloid (Abeta) aggregates is a characteristic of Alzheimer's disease (AD). Furthermore, these aggregates have neurotoxic effects on cells, and thus, molecules that inhibit Abeta aggregate formation could be valuable therapeutics for AD. It is well known that aggregation of Abeta depends on its hydrophobicity, and thus, in order to increase the hydrophilicity of Abeta, we considered using citrate, an anionic surfactant with three carboxylic acid groups.

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The dissection of the intracranial vertebral artery (VAD) is a common cause of young age brain stem stroke. VAD can be detected by conventional angiography, but there is yet no agreement on the most effective tool to use for the detection of VAD. Here, we report a patient with VAD, who was diagnosed with an intimal flap within the left vertebral artery by the magnetic resonance angiography (MRA) source images.

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During our investigation of the neuroprotective activity of Platycodi radix we found that an aqueous extract of this folk medicine exhibited significant protection against glutamate-induced toxicity in primary cultured rat cortical cells. In order to clarify the neuroprotective mechanism(s) of this observed effect, activity-guided isolation was performed to seek and identify active fractions and components. By such fractionation, four known triterpene saponin compounds--platycodins A, C and D and deapioplatycodin D--were isolated from the n-butanol fraction.

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A sulfur compound, bis(4-hydroxybenzyl)sulfide (1) was isolated from the root extract of Pleuropterus ciliinervis. Its structure was elucidated using NMR spectroscopic techniques and mass spectrometric analysis. Compound 1 showed potent inhibitory activity in a histone deacetylase (HDAC) enzyme assay.

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The major constituents from the fruits of Maclura pomifera are the prenylated isoflavones, osajin (1) and pomiferin (2). Their structures were elucidated using NMR spectroscopic techniques and mass spectrometric analysis. Compound 2 showed potential inhibitory activity in histone deacetylase (HDAC) enzyme assay.

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It is well known that motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) of the motor cortex are facilitated by voluntary muscle contraction. We evaluated the effects of imagination of movements on MEP latencies of agonist and antagonist muscles in the hand using TMS. Twenty-two healthy volunteers were studied.

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The involvement of the nervous system in Kikuchi's disease (KD) is rare. Although some reports of meningeal involvement in KD were described in the literature from Japan, it has rarely been reported in Korea. A 23-year-old man presented with severe headache, fever, and vomiting.

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