Publications by authors named "Soo-Bong Choi"

We present a method that uses viscosity-lowering materials to fabricate flexible polydimethylsiloxane-based quantum dot (QD) films with high quantum yield (QY) and improved uniformity. We found that the aggregation of individual QDs was prevented, and the QY improved simultaneously in films that contained surfactants. These films showed an improved absorption of approximately 27% in the near-UV and blue light regions, along with an improved photoluminescence of approximately 18%, indicating improved light conversion from the UV to the visible frequency region.

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The emergence of infectious diseases worldwide necessitates rapid and precise diagnostics. Using gold nanoshells in the PCR mix, we harnessed their unique photothermal properties in the near-infrared regime to attain efficient heating, reaching ideal photothermal PCR cycle temperature profile. Our photothermal PCR method expedited DNA amplification while retaining its detection sensitivity.

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While liver histopathology is heterogeneous in diabetes, the underlying mechanisms remain unclear. We investigated whether glycemic variation resulting from differential diets can induce heterogeneity in diabetic liver and the underlying molecular mechanisms. We generated end-stage non-obese diabetic model rats by subtotal-pancreatectomy in male Sprague- Dawley rats and ad libitum diet for 7 weeks (n = 33).

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Thermally reducible pyroprotein-based electronic textiles (e-textiles) are fabricated using graphene oxide and a pyroprotein such as cocoon silk and spider web without any chemical agents. The electrical conductivity of the e-textile is 11.63 S cm , which is maintained even in bending, washing, and temperature variation.

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Euglycemia is the ultimate goal in diabetes care to prevent complications. However, the benefits of euglycemia in type 2 diabetes are controversial because near-euglycemic subjects show higher mortality than moderately hyperglycemic subjects. We previously reported that euglycemic-diabetic rats on calorie-control lose a critical liver weight (LW) compared with hyperglycemic rats.

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The presence and distribution characteristics of microplastics become a big issue due to the adverse effects on marine organisms caused by not only microplastics but any incorporated and/or adsorbed pollutants. Distribution of microplastics (50- to 5000-μm size) was determined for three sandy beaches on an isolated island in a high-tidal costal region to elucidate spatial distributions in relation to beach locations. The abundances of microplastics (n = 21) measured were 56-285,673 (46,334 ± 71,291) particles/m(2) corresponding to the highest level globally.

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We report near-field and far-field measurements of transmission through nanometer-sized gaps at near-infrared frequencies with varying the gap size from 1 nm to 10 nm. In the far-field measurements, we excluded direct transmission on the metal film surface via interferometric method. Kirchhoff integral formalism was used to relate the far-field intensity to the electric field at the nanogaps.

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Herein, we will propose a new application possibility of epsilon-near-zero (ENZ) materials: high resolution wide-field imaging. We show that the resolution can be dramatically enhanced by simply inserting a thin epsilon-near-zero (ENZ) material between the sample and substrate. By performing metal half-plane imaging, we experimentally demonstrate that the resolution could be enhanced by about 47% with a 300-nm-thick SiO interlayer, an ENZ material at 8-μm-wavelength (1250 cm).

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Intensive glucose control increases the all-cause mortality in type 2 diabetes mellitus (T2DM); however, the underlying mechanisms remain unclear. We hypothesized that strict diet control to achieve euglycemia in diabetes damages major organs, increasing the mortality risk. To evaluate effects on major organs when euglycemia is obtained by diet control, we generated a model of end-stage T2DM in 13-week-old Sprague-Dawley rats by subtotal pancreatectomy, followed by ad libitum feeding for 5 weeks.

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A resonant shift and a decrease of resonance quality of a tuning fork attached to a conventional fiber optic probe in the vicinity of liquid is monitored systematically while varying the protrusion length and immersion depth of the probe. Stable zones where the resonance modification as a function of immersion depth is minimized are observed. A wet near-field scanning optical microscope (wet-NSOM) is operated for a sample within water by using such a stable zone.

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Background: Achieving euglycaemia by continuous subcutaneous insulin infusion (CSII) therapy alone has been shown to restore β-cell function in patients with newly diagnosed type 2 diabetes. However, the efficacy has not been evaluated in patients with non-newly diagnosed type 2 diabetes and suboptimal glycaemic control.

Methods: Of the 1220 patients with type 2 diabetes who began CSII therapy from March 2000 to March 2007, we retrospectively selected patients using the following inclusion criteria: glycosylated haemoglobin (HbA1c ) ≥ 7.

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Yb(3+) and Ln(3+) (Ln(3+) = Er(3+) or Tm(3+)) codoped Lu(2)O(3) nanorods with cubic Ia3 symmetry have been prepared by low temperature hydrothermal procedures, and their luminescence properties and waveguide behavior analyzed by means of scanning near-field optical microscopy (SNOM). Room temperature upconversion (UC) under excitation at 980 nm and cathodoluminescence (CL) spectra were studied as a function of the Yb(+) concentration in the prepared nanorods. UC spectra revealed the strong development of Er(3+) (4)F(9/2) → (4)I(15/2) (red) and Tm(3+) (1)G(4) → (3)H(6) (blue) bands, which became the pre-eminent and even unique emissions for corresponding nanorods with the higher Yb(3+) concentration.

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Background: As in type 1 diabetes, continuous subcutaneous insulin infusion (CSII) therapy is emerging as a promising therapeutic option in type 2 diabetes. However, the insulin requirement profiles of patients with type 2 diabetes when treated via CSII with rapid-acting insulin analogs have not been well investigated.

Methods: We examined insulin requirement profiles of type 2 diabetes patients (n = 300; age, 57.

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Background: The effects of long-term continuous subcutaneous insulin infusion (CSII) on cardiovascular risk factors such as hyperglycaemia, dyslipidaemia, and proinflammatory cytokine levels have not been assessed so far in type 2 diabetes.

Methods: We analysed the levels of HbA(1c), serum lipids, tumor necrosis factor alpha (TNF-alpha), and interleukin 6 (IL-6) at 0, 2, and 30 weeks after CSII in 15 patients with type 2 diabetes (mean age, 53.3+/-10.

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Long-term dexamethasone (DEX) treatment is well known for its ability to increase insulin resistance in liver and adipose tissues leading to hyperinsulinemia. On the other hand, exercise enhances peripheral insulin sensitivity. However, it is not clear whether DEX and/or exercise affect beta-cell mass and function in diabetic rats, and whether their effects can be associated with the modulation of the insulin/IGF-I signaling cascade in pancreatic beta-cells.

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The effective control of blood glucose is the key to preventing or reversing diabetic complications. In this study, we examined the effects of Okchun-San (OCS), a Korean herbal medicine formula, on the blood glucose levels in diabetic C57BL/KsJ db/db mice. Herbal medicines were prepared from dried herbs by adding Coicis semen (OCS-C) or Oryzae semen (OCS-O).

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Extracts from Rhei Rhizoma extracts (RR) have been reported to attenuate metabolic disorders such as diabetic nephropathy, hypercholesterolemia and platelet aggregation. With this study we investigated the anti-diabetic action of 70% ethanol RR extract in streptozotocin-induced diabetic mice, and determined the action mechanism of active compounds of RR in vitro. In the diabetic mice, serum glucose levels at fasting and post-prandial states and glucose area under the curve at modified oral glucose tolerance tests were lowered without altering serum insulin levels, indicating that RR contained potential anti-diabetic agents.

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Clinical observation found that tramadol, mu opioid receptor (MOR) agonist and serotonin (5-HT) reuptake inhibitor, has a hypoglycemic effect in type 2 diabetes patients. The mechanism of its hypoglycemic effect has not been fully defined. This study showed that tramadol activated a neuronal insulin signaling cascade by increasing the induction of insulin receptor substrate-2 expression in primary cultured neuronal cells while this activation was suppressed by naloxone (MOR inhibitor) and dexamethasone (non-specific inhibitor of MOR and 5-HT receptor, DEX).

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Our preliminary study demonstrated that 70% ethanol Cortidis Rhizoma extracts (CR) had a hypoglycemic action in diabetic animal models. We determined whether CR fractions acted as anti-diabetic agent, and a subsequent investigation of the action mechanism of the major compound, berberine ([C(20)H(18)NO(4)](+)), was carried out in vitro. The 20, 40 and 60% methanol fractions from the XAD-4 column contained the most insulin sensitizing activities in 3T3-L1 adipocytes.

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The prevalence and progression of type 2 diabetes have increased remarkably in postmenopausal women. Although estrogen replacement and exercise have been studied for their effect in modulating insulin sensitivity in the case of insufficient estrogen states, their effects on beta-cell function and mass have not been studied. Ovariectomized (OVX) female rats with 90% pancreatectomy were given a 30% fat diet for 8 wk with a corresponding administration of 17beta-estradiol (30 microg/kg body weight) and/or regular exercise.

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Purpose: To determine the feasibility of using a commercially available microinfusion pump for the continuous delivery of eye drops using a rabbit model.

Design: Laboratory investigation.

Methods: Tear secretion was measured after attaching a microinfusion pump to the superior fornix of a rabbit.

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In the present study, we screened candidates for enhancing insulin action, using glucose uptake as an indicator, from Liriope platyphylla Wang et Tang (LPWT) extract, Liliaceae, in 3T3-L1 adipocytes. The mechanism of insulin sensitizing action in the fractions was also investigated. LPWT extract with 70% MeOH was sequentially separated with Diaion HP-20 and silica gel column chromatography.

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Background: Recent research has reported that high sugar diets increase insulin resistance, without abdominal obesity, in male, but not female Wistar rats. Whether a high sucrose (SU) diet increased insulin resistance in ovariectomized (OVX) rats was determined.

Methods: Female Sprague Dawley rats, weighing 273 +/- 20 g, had either an ovariectomy or a sham operation (sham).

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Background: Our previous studies showed that some Korean type 2 diabetic patients could maintain long-term normal blood glucose control without any medication, referred to as remission after a certain period of normalization of blood glucose level by continuous subcutaneous insulin infusion (CSII) treatment. In this study we determined the clinical characteristics that influenced the induction of remission.

Methods: Ninety-one type 2 diabetes mellitus (DM) patients were treated with CSII therapy.

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Synopsis of recent research by authors named "Soo-Bong Choi"

  • - Soo-Bong Choi's recent research focuses on advanced materials and their applications, particularly in the fields of nanotechnology and biomedical diagnostics, as evidenced by the development of uniform quantum dot films and photothermal PCR equipment.
  • - The exploration of metabolic effects in diabetic rats highlights Choi's interest in understanding the molecular mechanisms behind the pathophysiology of diabetes, linking liver histopathology and organ weight loss to diet control and autophagy.
  • - Additionally, Choi investigates environmental issues, exemplified by research on microplastic distribution in coastal areas, emphasizing the ecological impact and the necessity for monitoring pollutants in marine ecosystems.

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