Publications by authors named "Jongsik Park"

Nanostructured high-/medium-entropy compounds have emerged as important catalytic materials for energy conversion technologies, but complex thermodynamic relationships involved with the element mixing enthalpy have been a considerable roadblock to the formation of stable single-phase structures. Cation exchange reactions (CERs), in particular with copper sulfide templates, have been extensively investigated for the synthesis of multicomponent heteronanoparticles with unconventional structural features. Because copper cations within the host copper sulfide templates are stoichiometrically released with incoming foreign cations in CERs to maintain the overall charge balance, the complete absence of Cu cations in the nanocrystals after initial CERs would mean that further compositional variation would not be possible by subsequent CERs.

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  • This study explored the relationship between regional cerebral blood flow (rCBF) and neuropsychiatric symptoms in early Alzheimer’s disease (AD) through SPECT scans of 59 patients.* -
  • Results showed that different neuropsychiatric symptom domains (affective, apathy, hyperactivity, and psychotic) correlated with varying levels of rCBF in specific brain regions, particularly in the prefrontal cortex.* -
  • The findings suggest both common and distinct brain perfusion patterns linked to neuropsychiatric symptoms in early AD, indicating a need for further research with larger samples to validate the results.*
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  • Preclinical studies hint that low-intensity transcranial focused ultrasound (tFUS) could help Alzheimer's patients by potentially opening the blood-brain barrier (BBB), reducing amyloid buildup, and enhancing cognitive function.
  • In a clinical trial with eight AD patients, tFUS was applied to the right hippocampus, but no BBB opening was observed; however, immediate recall and recognition memory showed significant improvements.
  • PET scans revealed increased cerebral glucose metabolism in the right hippocampus, correlating with better memory performance, indicating short-term cognitive benefits from tFUS despite the lack of BBB opening; further research is needed to confirm efficacy and safety.
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  • A pilot study examined the effects of low-intensity transcranial focused ultrasound (tFUS) on patients with Alzheimer's disease (AD), focusing on its impact on the blood-brain barrier, cerebral glucose metabolism, and cognition.
  • The study involved four AD patients receiving tFUS targeting the hippocampus, and assessments included MRI, PET scans, and cognitive tests before and after the procedure.
  • Results indicated improved glucose metabolism in specific brain regions and mild cognitive improvements, with no adverse effects reported, suggesting potential benefits of tFUS in AD that warrant further research.
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The neuropathology of Parkinson's disease dementia (PDD) is heterogenous, and the impacts of each pathophysiology and their synergistic effects are not fully understood. The aim of this study was to evaluate the frequency and impacts of co-existence with Alzheimer's disease in patients with PDD by using 18F-florbetaben PET imaging. A total of 23 patients with PDD participated in the study.

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Nanocrystals with multiple compositions and heterointerfaces have received great attention due to promising multifunctional and synergistic physicochemical properties. In particular, heterointerfaces have been at the focal point of nanocatalyst research because the strain caused by lattice mismatches between different phases is the dominant determinant of surface energy and catalytic activity. The ensemble effects of different material phases have also contributed to the interest in heterointerfaced multicomponent materials.

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Background And Purpose: Despite accumulating evidence for the clinical efficacy and neuroprotective properties of rasagiline in Parkinson's disease (PD), effects of rasagiline on brain perfusion in PD patients have not been elucidated. The present study aimed to investigate the effects of rasagiline on regional cerebral blood flow (rCBF) in patients with PD using single-photon emission computed tomography (SPECT).

Methods: A total of 44 PD patients were recruited and treated with dopamine agonist, either alone or in combination with levodopa.

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  • Directed alignment of polymer chains is crucial for improving charge transport properties in materials.
  • The study focuses on synthesizing a lyotropic liquid crystalline conjugated polymer (CP1-P) with photocleavable side chains to facilitate this alignment.
  • By using a floating film transfer method and optimizing solvent conditions, they achieved significantly higher hole transport mobility along the aligned polymer chains compared to the perpendicular direction.
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Background: Although single or multiple sessions of transcranial direct current stimulation (tDCS) on the prefrontal cortex over a few weeks improved cognition in patients with Alzheimer's disease (AD), effects of repeated tDCS over longer period and underlying neural correlates remain to be elucidated.

Objective: This study investigated changes in cognitive performances and regional cerebral metabolic rate for glucose (rCMRglc) after administration of prefrontal tDCS over 6 months in early AD patients.

Methods: Patients with early AD were randomized to receive either active (n = 11) or sham tDCS (n = 7) over the dorsolateral prefrontal cortex (DLPFC) at home every day for 6 months (anode F3/cathode F4, 2 mA for 30 min).

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  • - The study focuses on understanding apathy in Alzheimer's disease (AD) patients, which is common but not well understood, especially how it affects disease progression.
  • - Researchers compared regional cerebral blood flow (rCBF) using SPECT scans between 66 AD patients with apathy and 66 without, finding significant differences in certain brain areas.
  • - Results indicated that patients with apathy had lower rCBF in specific regions like the orbitofrontal cortex and insula, suggesting that decreased blood flow in these areas may relate to the symptoms of apathy.
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Background: Amnestic mild cognitive impairment (aMCI) is highly likely to progress to dementia of the Alzheimer type (DAT). One of the most frequently reported symptoms in aMCI and DAT patients is memory impairment. This study compared the levels of beliefs about memory efficacy and control, cognitive activity, and depression among healthy older adults (OA), patients with aMCI, and patients with DAT.

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Direct methanol fuel cell technology awaits the development of highly efficient and robust nanocatalysts driving the methanol oxidation reaction (MOR) in a CO poisoning-free fashion. Thus far, various Pt-based alloy nanoparticles have been studied as electrocatalysts toward the MOR, and it has been found that the introduction of dopants such as Ru and Cu to Pt has been particularly successful in mitigating the CO poisoning problem. Herein, we report a facile synthesis of Ru-branched RuPtCu nanocages that involves in situ formation of Ru-doped PtCu nanoparticles and subsequent outgrowth of Ru branches by insertion of additional Ru precursors.

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Post-synthetic transformation of nanoparticles has received great attention, because this approach can provide an unusual route to elaborately composition-controlled nanostructures while maintaining the overall structure of the template. In principle, anisotropic heteronanoparticles of semiconductor materials can be synthesized via localized, that is, single site, cation exchange in symmetric nanoparticles. However, the differentiation of multiple identical cation exchange sites in symmetric nanoparticles can be difficult to achieve, especially for semiconductor systems with very fast cation exchange kinetics.

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While the realization of clean and sustainable energy conversion systems primarily requires the development of highly efficient catalysts, one of the main issues had been designing the structure of the catalysts to fulfill minimum cost as well as maximum performance. Until now, noble metal-based nanocatalysts had shown outstanding performances toward the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). However, the scarcity and high cost of them impeded their practical use.

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Highly active and durable electrocatalysts for the hydrogen evolution reaction (HER) may play a pivotal role in commercial success of electrolytic water splitting technology. Among various material classes, binary metal sulphides show a great promise as HER catalysts because of their tunable energy levels conducive to a high catalytic activity and high robustness under harsh operating conditions. On the other hand, facet-controlled nanoparticles with controlled surface energies have gained great recent popularity as active and selective catalysts.

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Pt-based nanoframe catalysts have been explored extensively due to their superior activity toward the oxygen reduction reaction (ORR). Herein, we report the synthesis of Pt-Ni multiframes, which exhibit the unique structure of tightly fused multiple nanoframes and reinforced by an embedded dendrite. Rapid reduction and deposition of Ni atoms on Pt-Ni nanodendrites induce the alloying/dealloying of Pt and Ni in the overall nanostructures.

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  • Nicergoline is a drug used to treat cognitive deficits in conditions like Alzheimer's disease, and this study aimed to explore its effect on brain blood flow in AD patients.
  • Sixteen early AD patients received nicergoline for 1.5 years, undergoing cognitive tests and brain scans before and after treatment.
  • While changes in cognition and daily living tasks were not statistically significant, the study found increased blood flow in specific brain regions, suggesting nicergoline may help delay cognitive decline in AD.
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The development of highly active electrocatalysts is crucial for the advancement of renewable energy conversion devices. The design of core-shell nanoparticle catalysts represents a promising approach to boost catalytic activity as well as save the use of expensive precious metals. Here, a simple, one-step synthetic route is reported to prepare hexagonal nanosandwich-shaped Ni@Ru core-shell nanoparticles (Ni@Ru HNS), in which Ru shell layers are overgrown in a regioselective manner on the top and bottom, and around the center section of a hexagonal Ni nanoplate core.

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Pt-based alloy nanoframes have shown great potential as electrocatalysts toward the oxygen reduction reaction (ORR) in fuel cells. However, the intrinsically infirm nanoframes could be severely deformed during extended electro-cyclings, which eventually leads to the loss of the initial catalytic activity. Therefore, the structurally robust nanoframe is a worthy synthetic target.

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  • Sleep disturbances in Alzheimer's disease (AD) patients are common but not well understood, prompting a study to investigate the connection between regional cerebral blood flow (rCBF) and sleep disturbances using advanced imaging techniques.
  • The study involved 140 AD patients divided into two groups: those with sleep loss and those without, where sleep loss was measured through a specific inventory.
  • Results showed significant differences in brain perfusion between the two groups, with decreased blood flow in certain frontal and temporal regions of the brain in patients experiencing sleep disturbances, suggesting these areas may be linked to sleep issues in AD.
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Nanoframe electrocatalysts have attracted great interest due to their inherently high active surface area per a given mass. Although recent progress has enabled the preparation of single nanoframe structures with a variety of morphologies, more complex nanoframe structures such as a double-layered nanoframe have not yet been realized. Herein, we report a rational synthetic strategy for a structurally robust Ir-based multimetallic double-layered nanoframe (DNF) structure, nanoframe@nanoframe.

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  • This study explored the effects of acetyl-L-carnitine (ALC) treatment on cerebral blood flow in patients with early Alzheimer's disease (AD) using brain imaging techniques.
  • Eighteen AD patients received ALC at a daily dose of 1.5 g for an average of 1.4 years, with assessments conducted on cognitive and neuropsychiatric measures before and after treatment.
  • Results showed increased blood flow in the right precuneus and decreased flow in certain brain areas, but overall cognitive and behavioral scores did not significantly change, suggesting that ALC might have specific effects on brain regions without worsening clinical symptoms.
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Background And Purpose: Although subjective cognitive impairment (SCI) is often accompanied by Parkinson's disease (PD) and may predict the development of mild cognitive impairment or dementia, longitudinal brain perfusion changes in PD patients with SCI remain to be elucidated. The current prospective study examined cerebral perfusion changes in PD patients with SCI using technetium-99m hexamethylpropylene amine oxime single photon emission computed tomography (SPECT).

Methods: Among 53 PD patients at baseline, 30 patients were classified into the PD with SCI group and 23 patients were assigned to the PD without SCI group.

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Background: In preparation for I ablation, temporary withdrawal of thyroid hormone is commonly used in patients with thyroid cancer after total thyroidectomy. The current study aimed to investigate brain glucose metabolism and its relationships with mood or cognitive function in these patients using F-fluoro-2-deoxyglucose positron emission tomography (F-FDG-PET).

Method: A total of 40 consecutive adult patients with thyroid carcinoma who had undergone total thyroidectomy were recruited for this cross-sectional study.

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of RhCu alloy truncated octahedral nanoframes, Cu@Rh core-shell nanoparticles, and a bundle of five RhCu nanowires is demonstrated. The RhCu alloy 3D nanoframe, in particular, exhibits excellent catalytic activity toward the oxygen evolution reaction under alkaline conditions.

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