Publications by authors named "O.-H. Lee"

Article Synopsis
  • By age 40, over 90% of adults with Down syndrome develop Alzheimer’s disease, with many progressing to dementia, despite having few typical vascular risk factors.
  • This study analyzed how small vessel cerebrovascular disease impacts Alzheimer's disease progression and neurodegeneration in adults with Down syndrome, using MRI and plasma biomarker data from 185 participants.
  • Results indicated a complex relationship where white matter hyperintensity (WMH) levels influenced phosphorylated tau, linked by glial fibrillary acidic protein, suggesting that cerebrovascular health affects Alzheimer’s pathology in this population.
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Article Synopsis
  • Small interfering RNAs (siRNAs) have the potential to target and silence difficult disease-related genes, providing new ways to treat diseases.* -
  • While delivering siRNAs to the liver via N-acetylgalactosamine (GalNAc) has proven effective, delivering siRNAs to other cell types remains a challenge.* -
  • Research shows that certain cellular mechanisms, including retrograde transport and lipid droplets, can enhance the effectiveness of siRNA delivery and gene silencing in both liver and non-liver cell types.*
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Glycolaldehyde [HOCHC(O)H, GA], the primitive sugar-like molecule detected in the interstellar medium (ISM), is a potential precursor for the synthesis of complex sugars. Despite its importance, the mechanism governing the formation of these higher-order sugars from GA under interstellar circumstances remains elusive. Radical intermediates HOCHCHO (), HOCHCHOH (), HOCHCO (), HOCHC(O)H (), and OCHC(O)H () derived from GA could be potential precursors for the formation of glyceraldehyde (aldose sugar), dihydroxyacetone (ketose sugar), and ethylene glycol (sugar alcohol) in dark regions of ISM.

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Objective: To compare postprandial glucose excursions following a bolus with inhaled technosphere insulin (TI) or subcutaneous rapid-acting analog (RAA) insulin.

Research Design And Methods: A meal challenge was completed by 122 adults with type 1 diabetes who were using multiple daily injections (MDI), a nonautomated pump, or automated insulin delivery (AID) and who were randomized to bolus with their usual RAA insulin (n = 61) or TI (n = 61).

Results: The primary outcome, the treatment group difference in area under the curve for glucose >180 mg/dL over 2 h, was less with TI versus RAA (adjusted difference -12 mg/dL, 95% CI -22 to -2, P = 0.

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Electronic waste (e-waste) and diabetes are global challenges to modern societies. However, solving these two challenges together has been challenging until now. Herein, we propose a laser-induced transfer method to fabricate portable glucose sensors by recycling copper from e-waste.

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Analyzing the concentration of ions in aqueous solutions in real-time plays an important role in the fields of chemistry and biology. Traditional methods for measuring ion concentrations, such as concentration analysis by measuring electrical conductivity, inductively coupled plasma mass spectrometry, and ion chromatography, have been used in many research fields. However, these methods are limited in determining ion concentrations instantaneously.

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ConspectusChemists have long been inspired by biological photosynthesis, wherein a series of excited-state electron transfer (ET) events facilitate the conversion of low energy starting materials such as HO and CO into higher energy products in the form of carbohydrates and O. While this model for utilizing light-driven charge transfer to drive catalytic reactions thermodynamically "uphill" has been extensively adapted for small molecule activation, molecular machines, photoswitches, and solar fuel chemistry, its application in organic synthesis has been less systematically developed. However, the potential benefits of these approaches are significant, both in enabling transformations that cannot be readily achieved using conventional thermal chemistry and in accessing distinct selectivity regimes that are uniquely enabled by excited-state mechanisms.

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A series of mononuclear manganese(III)-hydroxo and -aqua complexes, [Mn(TBDAP)(OH)] (), [Mn(TBDAP)(OH)(OH)] () and [Mn(TBDAP)(OH)] (), were prepared from a manganese(II) precursor and confirmed using various methods including X-ray crystallography. Thermodynamic analysis showed that protonation from hydroxo to aqua species resulted in increased redox potentials () in the order of (-0.15 V) < (0.

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Reaction of a rare and well-characterized Mn-superoxo species, Mn(BDPP)(O⋅) (1, HBDPP=2,6-bis((2-(S)-di(4-bromo)phenylhydroxylmethyl-1-pyrrolidinyl)methyl)pyridine), with 4-dimethylaminophenol at -80 °C proceeds via concerted proton electron transfer (CPET) to produce a Mn-hydroperoxo complex, Mn(BDPP)(OOH) (2), alongside 4-dimethylaminophenoxy radical; whereas, upon treatment with 4-nitrophenol, complex 1 undergoes a proton transfer process to afford a Mn-hydroperoxo complex, [Mn(BDPP)(OOH)] (3). Intriguingly, the reactions of 1 with 4-chlorophenol and 4-methoxyphenol follow two routes of CPET and sequential proton and electron transfer to furnish complex 2 in the end. UV-vis and EPR spectroscopic studies coupled with DFT calculations provided support for this wide mechanistic spectrum of activating various phenol O-H bonds by a single Mn-superoxo complex, 1.

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Despite decades of faculty professional development programs created to prepare women for leadership, gender inequities persist in salary, promotion, and leadership roles. Indeed, men still earn more than women, are more likely than women to hold the rank of professor, and hold the vast majority of positions of power in academic medicine. Institutions demonstrate commitment to their faculty's growth by investing resources, including creating faculty development programs.

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The skeletal muscles account for approximately 40% of the body weight and are crucial in movement, nutrient absorption, and energy metabolism. Muscle loss and decline in function cause a decrease in the quality of life of patients and the elderly, leading to complications that require early diagnosis. Positron emission tomography/computed tomography (PET/CT) offers non-invasive, high-resolution visualization of tissues.

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Reactions of Co(OAc)·4HO, -bis(3-pyridylmethyl)oxalamide () and 4,4'-sulfonyldibenzoic acid (HSDA) afforded four coordination polymers with the same mixed ligands, {[Co()(SDA)(HO)]·HO·CHOH}, , {[Co()(SDA)]·2HO·0.5}, , {[Co()(SDA)(HO)]·HO}, , and {[Co()(SDA)(HO)]·4HO}, , which have been structurally characterized using single-crystal X-ray crystallography. Complexes - are 2D layers, revealing topologies of , 2,6L1, (4,4)Ia, and 6L12, respectively, and demonstrating that the metal-to-ligand ratio, solvent system, and reaction temperature are important in determining the structural diversity.

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Spin engineering is a promising way to modulate the interaction between the metal d-orbital and the intermediates and thus enhance the catalytic kinetics. Herein, an innovative strategy is reported to modulate the spin state of Co by regulating its coordinating environment. o-c-CoSe-Ni is prepared as pre-catalyst, then in situ electrochemical impedance spectroscopy (EIS) and in situ Raman spectroscopy are employed to prove phase transition, and CoOOH/CoO is formed on the surface as active sites.

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Volumetric super-resolution microscopy typically encodes the 3D position of single-molecule fluorescence into a 2D image by changing the shape of the point spread function (PSF) as a function of depth. However, the resulting large and complex PSF spatial footprints reduce biological throughput and applicability by requiring lower labeling densities to avoid overlapping fluorescent signals. We quantitatively compare the density dependence of single-molecule light field microscopy (SMLFM) to other 3D PSFs (astigmatism, double helix and tetrapod) showing that SMLFM enables an order-of-magnitude speed improvement compared to the double helix PSF by resolving overlapping emitters through parallax.

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Climate change can affect precipitation patterns, temperature, and the hydrological cycle, consequently influencing the dynamics of nitrogen (N) within aquatic ecosystems. In this study, multiple stable isotopes (N-NO/O-NO and H-HO/O-HO) were used to investigate the N sources and flowpath within the Bogang stream in South Korea. Within the vicinity of the stream with complex land use where various N sources were present, four end-members (rainfall, soil, sewage, and livestock) were sampled and examined.

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Purpose: To evaluate the biomechanical effects of acellular human dermal allograft tuberoplasty (AHDAT) in a cadaveric model of an irreparable supraspinatus + anterior one-half infraspinatus (stage III) rotator cuff tear.

Methods: Eight cadaveric shoulders were tested at 20°, 40°, and 60° of glenohumeral abduction (AB) and 0°, 30°, 60°, and 90° of external rotation (ER). Superior humeral translation, acromiohumeral distance, and subacromial contact were quantified for 4 conditions: (1) intact, (2) stage III tear (entire supraspinatus and anterior one-half infraspinatus), (3) single-layer AHDAT, and (4) double-layer AHDAT.

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Alkoxide precursors have been highlighted for depositing carbon-free films, but their use in Atomic Layer Deposition (ALD) often exhibits a non-saturated growth. This indicates no self-limiting growth due to the chain reaction of hydrolysis or ligand decomposition caused by β-hydride elimination. In the previous study, we demonstrated that self-limiting growth of ALD can be achieved using our newly developed precursor, hafnium cyclopentadienyl tris(N-ethoxy-2,2-dimethyl propanamido) [HfCp(edpa)3].

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The reaction of CHCHOO with HC(O)OH has a large rate coefficient so that it might play a significant role in the formation of secondary organic aerosols (SOA) in the atmosphere. We investigated the detailed mechanism and kinetics of the reactions of Criegee intermediate - and -CHCHOO with HC(O)OH with a step-scan Fourier-transform infrared spectrometer by recording time-resolved absorption spectra of transient species and end products produced upon irradiation at 308 nm of a flowing mixture of CHCHI/O/HC(O)OH at 298 K and 60 Torr. Thirteen bands of hydroperoxyethyl formate [HC(O)OCH(CH)OOH, HPEF], the hydrogen-transferred adduct of CHCHOO and HC(O)OH, were observed.

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We report the synthesis and characterization of a mononuclear nonheme cobalt(III)-imidyl complex, [Co(NTs)(TQA)(OTf)] (), with an = 3/2 spin state that is capable of facilitating exogenous substrate modifications. Complex was generated from the reaction of Co(TQA)(OTf) with PhINTs at -20 °C. A flow setup with ESI-MS detection was used to explore the kinetics of the formation, stability, and degradation pathway of in solution by treating the Co(II) precursor with PhINTs.

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The IR spectra of benzoic acid (BA), (BA)(HO) and (BA)(HO) ( = 1, 2) clusters, and their ring-deuterated isotopologues in the 2800-3750 cm region were measured with IR-vacuum ultraviolet spectroscopy under the jet-cooled condition. For (BA)(HO) and (BA)(HO), only a single isomer was observed for each species, whereas for (BA)(HO) and (BA)(HO), more than one isomers were present. The observed IR spectra were very complex and showed similar structures between (BA)(HO) and their ring-deuterated isotopologues (BA-)(HO) for specific values of and .

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Oncolytic viruses are of significant clinical interest due to their ability to directly infect and kill tumors and enhance the anti-tumor immune response. Previously, we developed KLS-3010, a novel oncolytic virus derived from the International Health Department-White (IHD-W) strain vaccinia virus, which has robust tumoricidal effects. In the present study, we generated a recombinant oncolytic virus, KLS-3020, by inserting three transgenes (hyaluronidase [PH-20], interleukin-12 [IL-12], and soluble programmed cell death 1 fused to the Fc domain [sPD1-Fc]) into KLS-3010 and investigated its anti-tumor efficacy and ability to induce anti-tumor immune responses in CT26.

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Conversion of methane (CH) to ethylene (CH) and/or acetylene (CH) enables routes to a wide range of products directly from natural gas. However, high reaction temperatures and pressures are often required to activate and convert CH controllably, and separating C products from unreacted CH can be challenging. Here, we report the direct conversion of CH to CH and CH driven by non-thermal plasma under ambient (25 °C and 1 atm) and flow conditions over a metal-organic framework material, MFM-300(Fe).

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The uranium inventory in the Boeun aquifer is situated near an artificial reservoir (40-70 m apart) intended to supply water to nearby cities. However, toxic radionuclides can enter the reservoir. To determine the U mobility in the system, we analyzed groundwater and fracture-filling materials (FFMs) for environmental tracers, including microbial signatures, redox-sensitive elements and isotopes.

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A series of manganese(II) and oxomanganese(IV) complexes supported by neutral, pentadentate ligands with varied equatorial ligand-field strength (N3pyQ, N2py2I, and N4py) were synthesized and then characterized using structural and spectroscopic methods. On the basis of electronic absorption spectroscopy, the [Mn(O)(N4py)] complex has the weakest equatorial ligand field among a set of similar Mn-oxo species. In contrast, [Mn(O)(N2py2I)] shows the strongest equatorial ligand-field strength for this same series.

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