Publications by authors named "Youngsun Kim"

43 Publications

Acute acalculous cholecystitis as the initial manifestation of systemic lupus erythematous: A case report.

Medicine (Baltimore) 2021 Jun;100(22):e26238

Department of Obstetrics and Gynecology, Kyung Hee University Medical Center, Kyung Hee University College of Medicine, Seoul, Korea.

Rationale: Acute acalculous cholecystitis (AAC) is an extremely rare manifestation of systemic lupus erythematous (SLE). In previous reports, most of the patients were already diagnosed cases of SLE upon confirmation of AAC.

Patient Concerns: A 24-year-old female who initially presented with fever and acute right upper quadrant abdominal pain. She had no medical history.

Diagnoses: Abdominal ultrasonography and computed tomography (CT) showed gallbladder thickening with pericholecystic edema without gallstones or sludge, demonstrating acalculous cholecystitis. She revealed discoid rash on the both shin. Laboratory tests revealed pancytopenia. The titer of antinuclear antibody (ANA) was 1:1280. Anti-dsDNA antibody, anti-phospholipid antibody, anti-Sm antibody test, and proteinuria in 24 hours were positive. Both C3 and C4 were low. Echocardiography and chest CT showed pericardial effusion and pleural effusion. Using the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria, the score was 31. We thought AAC of this case that was one of the initial manifestations of SLE.

Interventions: The patient was treated with high-dose prednisolone (1 mg/kg) and hydroxychloroquine 400 mg.

Outcomes: After 4 days of administration of high-dose corticosteroid therapy, symptoms rapidly improved. After 35 days of the treatment, her symptoms and disease activity of SLE were markedly improved.

Lessons: Although AAC being the initial manifestation of SLE is very rare, prompt diagnosis and management with corticosteroids precluded surgical intervention. Physicians need to be cognizant of AAC as a disease flare and as a rare initial manifestation of SLE.
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http://dx.doi.org/10.1097/MD.0000000000026238DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8183780PMC
June 2021

A clinical trial of submucosal saline injection in inverted colonic diverticula.

Chin Med J (Engl) 2021 04 15;134(12):1511-1512. Epub 2021 Apr 15.

Department of Obstetrics and Gynecology, Kyung Hee University Hospital, Kyung Hee University College of Medicine, Seoul, Korea.

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http://dx.doi.org/10.1097/CM9.0000000000001485DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8213287PMC
April 2021

Cell cycle regulation in human hair follicle dermal papilla cells using nonthermal atmospheric pressure plasma-activated medium.

Medicine (Baltimore) 2021 Apr;100(13):e25409

Department of Obstetrics and Gynecology, Kyung Hee University Medical Center, Seoul, Republic of Korea.

Abstract: Nonthermal atmospheric pressure (NAP) plasmas have recently been developed and have been used for wound healing, blood coagulation, and cancer therapy. NAP plasmas can induce either cell proliferation or cell death, depending on the dose. Due to their efficacy and application easily, plasma activated mediums (PAMs) have been used in human cells recently.In atmosphere, NAP plasmas react with molecular content of air such as N2, O2, H2O vapor, etc, and generate a variety of reactive oxygen and nitrogen species. High reactive oxygen species (ROS) levels promote damage of cellular DNA, proteins, and lipids. Such damage can lead to cell-cycle arrest, and cellular death. However, low levels of ROS have been caused an increase in cell cycle progression.Human skin is arranged in 3 layers, including (from top to bottom) the epidermis (and its appendages), the dermis, and the hypodermis. Human dermal papilla cells (DPCs) are located in the middle or even deep part of the dermis. DPCs play a key role in hair regeneration, and a lot of effort have been made to promote DPC hair formation ability. DPC is increased proliferation, delayed senescence, and enhanced hair by depending on the amount of ROS through the NAP-PAM treatment.In this study, we used NAP plasmas to the human hair follicle DPCs exposed from 0 to 20 minutes, so we were investigated the effects of PAM on cell proliferation and cell cycle progression. After NAP-PAM treatment for 24 hours, cell cycle was arrested in the G0/G1 phase. The NAP-PAM-treated human hair follicle DPCs recovered gradually after 48 hours of the treatment compared to the untreated cells.Therefore, this approach offers promising results for further application of NAP-PAM in clinical dermatology. In future, it can be applied clinically in the form of active water that can delay the progression of baldness and alopecia areata.
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http://dx.doi.org/10.1097/MD.0000000000025409DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8021305PMC
April 2021

Lymphoepithelioma-like carcinoma of the vagina: A rare case report and review of the literature.

J Obstet Gynaecol Res 2021 May 1;47(5):1917-1921. Epub 2021 Mar 1.

Department of Pathology, Kyung Hee Medical Center, College of Medicine, Kyung Hee university, Seoul, Republic of Korea.

A 78-year-old woman with the chief complaint of vaginal bleeding was referred to our institution. Pelvic magnetic resonance imaging showed a 2.1 cm × 2.0 cm soft tissue mass in the left vaginal area with left inguinal lymph node enlargement. A positron emission tomography/computer tomography scan showed a focal hypermetabolic lesion in the left vaginal area with involvement of vulvar area. Pelvic examination showed a vaginal wall mass and the patient underwent surgical excision of the mass. The results of pathology indicated lymphoepithelioma-like carcinoma (LELC) in the vagina. The patient was admitted subsequently in the oncological department for additional chemoradiation treatment. LELC is extremely rare in the vagina, and only three cases have been reported in the literature. Here we report an extremely rare case of this tumor and review of the previous literature.
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http://dx.doi.org/10.1111/jog.14722DOI Listing
May 2021

Multilevel Latent Class Profile Analysis: An Application to Stage-Sequential Patterns of Alcohol Use in a Sample of Canadian Youth.

Eval Health Prof 2021 Mar 29;44(1):50-60. Epub 2021 Jan 29.

Department of Statistics, 34973Korea University, Seoul, South Korea.

Recently, latent class analysis (LCA) and its variants have been proposed to identify subgroups of individuals who follow similar sequential patterns of latent class membership for longitudinal study. A primary assumption underlying the family of LCA is that individual observations are independent. In many applications, however, particularly in research on adolescent substance use, individuals are often dependent because of multilevel data structure, where the unit of observation (e.g., students) is nested in higher level units (e.g., schools). In this study, we propose multilevel latent class profile analysis (MLCPA), which will allow us to analyze the longitudinal data with a multilevel structure under the framework of LCA. We apply an MLCPA using data from the COMPASS study, a 9-year study funded by the Canadian Institutes of Health Research and Health Canada, in order to identify representative sequential drinking patterns of Canadian youth and investigate whether these sequential patterns vary across schools. The MLCPA identified three common student-level drinking behaviors: , , and . The sequence of drinking behaviors can be classified into one of three longitudinal sequential patterns: , , and . In addition, MLCPA uncovered two latent clusters ( and ) out of 64 schools in Ontario and Alberta based on the prevalences of sequential drinking patterns.
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http://dx.doi.org/10.1177/0163278721989547DOI Listing
March 2021

Sensitivity-Enhancing Strategies in Optical Biosensing.

Small 2021 01 28;17(4):e2004988. Epub 2020 Dec 28.

Materials Science and Engineering Program and Texas Materials Institute, Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.

High-sensitivity detection of minute quantities or concentration variations of analytes of clinical importance is critical for biosensing to ensure accurate disease diagnostics and reliable health monitoring. A variety of sensitivity-improving concepts have been proposed from chemical, physical, and biological perspectives. In this review, elements that are responsible for sensitivity enhancement are classified and discussed in accordance with their operating steps in a typical biosensing workflow that runs through sampling, analyte recognition, and signal transduction. With a focus on optical biosensing, exemplary sensitivity-improving strategies are introduced, which can be developed into "plug-and-play" modules for many current and future sensors, and discuss their mechanisms to enhance biosensing performance. Three major strategies are covered: i) amplification of signal transduction by polymerization and nanocatalysts, ii) diffusion-limit-breaking systems for enhancing sensor-analyte contact and subsequent analyte recognition by fluid-mixing and analyte-concentrating, and iii) combined approaches that utilize renal concentration at the sampling and recognition steps and chemical signal amplification at the signal transduction step.
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http://dx.doi.org/10.1002/smll.202004988DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884068PMC
January 2021

Enhancing Surface Capture and Sensing of Proteins with Low-Power Optothermal Bubbles in a Biphasic Liquid.

Nano Lett 2020 10 21;20(10):7020-7027. Epub 2020 Jul 21.

Molecular binding in surface-based biosensing is inherently governed by diffusional transport of molecules in solution to surface-immobilized counterparts. Optothermally generated surface microbubbles can quickly accumulate solutes at the bubble-liquid-substrate interface due to high-velocity fluid flows. Despite its potential as a concentrator, however, the incorporation of bubbles into protein-based sensing is limited by high temperatures. Here, we report a biphasic liquid system, capable of generating microbubbles at a low optical power/temperature by formulating PFP as a volatile, water-immiscible component in the aqueous host. We further exploited zwitterionic surface modification to prevent unwanted printing during bubble generation. In a single protein-protein interaction model, surface binding of dispersed proteins to capture proteins was enhanced by 1 order of magnitude within 1 min by bubbles, compared to that from static incubation for 30 min. Our proof-of-concept study exploiting fluid formulation and optothermal add-on paves an effective way toward improving the performances of sensors and spectroscopies.
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http://dx.doi.org/10.1021/acs.nanolett.0c01969DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7572762PMC
October 2020

Retrospective analysis of prognostic value of the neutrophil-to-lymphocyte ratio in early miscarriages: A 8-year survey.

Authors:
Youngsun Kim

Medicine (Baltimore) 2020 Jul;99(27):e20888

Department of Obstetrics and Gynecology, Kyung Hee Medical Center, College of Medicine, Kyung Hee University, Seoul, Republic of Korea.

This study aims to identify prognostic value of neutrophil-to-lymphocyte ratio (NLR) in early miscarriages. A total of 260 pregnant women with vaginal spotting were recruited from the Department of Obstetrics and Gynecology of the Kyung Hee Medical Center from January 1, 2011, and December 31, 2018. Venous samples were obtained from the women for measurements of platelet-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and NLR. All the patients were in < 14 gestational weeks of their pregnancy. Eighty-four patients were excluded because of incomplete data, loss of follow-up, and serious medical diseases. We enrolled 176 women for analysis and divided them into two groups. Group 1 included 104 women with threatened abortion; and group 2, 72 women with missed abortion. A significant difference in NLR was found between the groups (p = 0.001; P < .01). The multivariate analysis also revealed that NLR was the only prognostic factor of early miscarriage (odd ratio [OR], 0.732; 95% confidence interval [CI], 0.612-0.881, P = .001). The area under the Receiver-operating characteristic of NLR for distinguishing between the missed and threatened abortion groups was 0.792, and the best cutoff value was 5.72 (P < .05).
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http://dx.doi.org/10.1097/MD.0000000000020888DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7337448PMC
July 2020

Does Perceived Ageism Widen the Digital Divide? And Does It Vary by Gender?

Gerontologist 2020 09;60(7):1213-1223

School of Social Work, University of Alabama, Tuscaloosa.

Background And Objectives: Existing literature presents a widening digital divide among older adults in addition to the consideration of the potential adverse impacts of ageism on internet use among the older adult population. Our study aimed to investigate (a) whether older adults' perceived ageism will be associated with their use of the internet and (b) whether the relationship between perceived ageism and internet use will be moderated by age groups and binary gender.

Research Design And Methods: Using the data from the 2016 Health and Retirement Study, regression analyses were separately performed by gender. Two measures of perceived ageism were considered: (a) self-perception of aging and (b) perceived age discrimination.

Results: Our findings suggested that greater exposure to ageism is generally related to less use of the internet. In addition, we found divergent patterns in the relationship between ageism and internet use by gender. For women, a lower level of internet use was predicted by more negative perceptions of aging, whereas men's internet use was associated with the experience of age discrimination. Furthermore, interaction effects between age groups and ageism varied across gender. The negative perception of aging was more strongly associated with less internet use in older women than middle-aged women. In comparison, the perceived age discrimination predicted less internet use in middle-aged men than older men.

Discussion And Implications: Our findings suggest that perceived ageism is significantly associated with internet use, and its association differs by gender.
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http://dx.doi.org/10.1093/geront/gnaa066DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7491432PMC
September 2020

Treatment of Severe Hypertriglyceridemia-Induced Acute Pancreatitis with Subcutaneous Insulin: Case Report.

Clin Drug Investig 2020 07;40(7):671-674

Department of Obstetrics and Gynecology, Kyung Hee University Hospital, Kyung Hee University College of Medicine, Kyungheedae-ro 23, Dongdaemun-gu, Seoul, South Korea.

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http://dx.doi.org/10.1007/s40261-020-00928-0DOI Listing
July 2020

Intense Red-Emitting Upconversion Nanophosphors (800 nm-Driven) with a Core/Double-Shell Structure for Dual-Modal Upconversion Luminescence and Magnetic Resonance in Vivo Imaging Applications.

ACS Appl Mater Interfaces 2018 Apr 4;10(15):12331-12340. Epub 2018 Apr 4.

Korea University of Science and Technology , 217, Gajeong-ro , Yuseong-gu, Daejeon 34113 , Republic of Korea.

In this study, intense single-band red-emitting upconversion nanophosphors (UCNPs) excited with 800 nm near-infrared (NIR) light are reported. When a NaYF:Nd,Yb active-shell is formed on the 12.7 nm sized NaGdF:Yb,Ho,Ce UCNP core, the core/shell (C/S) UCNPs show tunable emission from green to red, depending on the Ce concentration under excitation with 800 nm NIR light. Ce-doped C/S UCNPs (30 mol %) exhibit single-band red emission peaking at 644 nm via a F → I transition of Ho. A high Nd concentration in the shell results in strong absorption at around 800 nm NIR light, even though the shell thickness is not large, and small-sized C/S UCNPs (16.3 nm) emit bright red light under 800 nm excitation. The formation of a thin NaGdF shell on the C/S UCNPs further enhances the upconversion (UC) luminescence and sub-20 nm sized core/double-shell (C/D-S) UCNPs exhibit 2.8 times stronger UC luminescence compared with C/S UCNPs. Owing to the strong UC luminescence intensity and Gd ions on the surface of nanocrystals, they can be applied as a UC luminescence imaging agent and a T contrast agent for magnetic resonance (MR) imaging. In vivo UC luminescence and high-contrast MR images are successfully obtained by utilizing the red-emitting C/D-S UCNPs.
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http://dx.doi.org/10.1021/acsami.7b18078DOI Listing
April 2018

Multifunctional Photonics Nanoparticles for Crossing the Blood-Brain Barrier and Effecting Optically Trackable Brain Theranostics.

Adv Funct Mater 2016 Oct 5;26(39):7057-7066. Epub 2016 Sep 5.

Center for Theragnosis and Center for Neuro-Medicine, Korea Institute of Science and Technology (KIST), Seoul 136-791, South Korea.

Theranostic photonic nanoparticles (TPNs) that cross the blood-brain barrier (BBB) and efficiently deliver a therapeutic agent to treat brain diseases, simultaneously providing optical tracking of drug delivery and release, are introduced. These TPNs are constructed by physical encapsulation of visible and/or near-infrared photonic molecules, in an ultrasmall micellar structure (<15 nm). Phytochemical curcumin is employed as a therapeutic as well as visible-emitting photonic component. In vitro BBB model studies and animal imaging, as well as ex vivo examination, reveal that these TPNs are capable of transmigration across the BBB and subsequent accumulation near the orthotopic xenograft of glioblastoma multiforme (GBM) that is the most common and aggressive brain tumor whose vasculature retains permeability-resistant properties. The intracranial delivery and release of curcumin can be visualized by imaging fluorescence produced by energy transfer from curcumin as the donor to the near-infrared emitting dye, coloaded in TPN, where curcumin induced apoptosis of glioma cells. At an extremely low dose of TPN, a significant therapeutic outcome against GBM is demonstrated noninvasively by bioluminescence monitoring of time-lapse proliferation of luciferase-expressing U-87 MG human GBM in the brain. This approach of TPN can be generally applied to a broad range of brain diseases.
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http://dx.doi.org/10.1002/adfm.201602808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5658140PMC
October 2016

Controlled Synthesis of CuInS/ZnS Nanocubes and Their Sensitive Photoluminescence Response toward Hydrogen Peroxide.

ACS Appl Mater Interfaces 2017 Sep 11;9(37):32097-32105. Epub 2017 Sep 11.

Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Republic of Korea.

We synthesized uniform CuInS/ZnS nanocubes by adjusting reaction parameters at the ZnS growth stage. Higher temperature and zinc concentration were shown to drive resultant crystals to have cubic morphology, which could be ascribed to the facet-dependent ligand dynamics on the crystal surface and concomitantly preferred directions of crystal growth. It was found that these nanocubes exhibit sensitive responses, as of photoluminescence quenching, toward hydrogen peroxide, compared to pyramid-shaped nanocrystals. The origin of quenching was further analyzed to be the oxidation of thiolate ligands that leaves the quenching center on the surface. It was noted that the quenched photoluminescence could be fully recovered by introducing additional ligand molecules into the system. Being adopted in the shape-controlled crystal growth, the ligand-to-crystal interaction was shown to still govern the interfacial reaction, the oxidation by hydrogen peroxide, of faceted crystals in our system. It turns out that the reactivity at the crystal surface depends on the exposed facets, especially induced by shape control, and the weak ligand-binding nature of the nanocube renders it vulnerable to the surface reaction.
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http://dx.doi.org/10.1021/acsami.7b09388DOI Listing
September 2017

Creep Behavior of High-Strength Concrete Subjected to Elevated Temperatures.

Materials (Basel) 2017 Jul 11;10(7). Epub 2017 Jul 11.

Department of Architectural Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea.

Strain is generated in concrete subjected to elevated temperatures owing to the influence of factors such as thermal expansion and design load. Such strains resulting from elevated temperatures and load can significantly influence the stability of a structure during and after a fire. In addition, the lower the water-to-binder (W-B) ratio and the smaller the quantity of aggregates in high-strength concrete, the more likely it is for unstable strain to occur. Hence, in this study, the compressive strength, elastic modulus, and creep behavior were evaluated at target temperatures of 100, 200, 300, 500, and 800 °C for high-strength concretes with W-B ratios of 30%, 26%, and 23%. The loading conditions were set as non-loading and 0.33f. It was found that as the compressive strength of the concrete increased, the mechanical characteristics deteriorated and transient creep increased. Furthermore, when the point at which creep strain occurred at elevated temperatures after the occurrence of transient creep was considered, greater shrinkage strain occurred as the compressive strength of the concrete increased. At a heating temperature of 800 °C, the 80 and 100 MPa test specimens showed creep failure within a shrinkage strain range similar to the strain at the maximum load.
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http://dx.doi.org/10.3390/ma10070781DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5551824PMC
July 2017

Laryngeal Closure during Swallowing in Stroke Survivors with Cortical or Subcortical Lesion.

J Stroke Cerebrovasc Dis 2017 Aug 26;26(8):1766-1772. Epub 2017 Apr 26.

Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, South Korea.

Background: One of the major, and most harmful, symptoms of dysphagia in stroke survivors is aspiration. Survivors of unilateral cortical strokes with dysphagia and resulting aspiration have been reported to have greater initiation delays in laryngeal closure than those who did not aspirate. Few studies have reported such data in survivors of subcortical stroke.

Methods: This study measured initiation of laryngeal closure (ILC) and laryngeal closure duration (LCD) in 2 groups of subjects: 15 stroke survivors with cortical lesions and 15 stroke survivors with subcortical lesions. Means and standard deviations of ILC and LCD were analyzed on 5-mL thin liquid and 5-mL puree boluses using a 100-ms timer during subsequent analysis of videofluoroscopic swallowing examinations. Statistical comparisons were used by repeated measures analysis of variance. Significance level was set at P < .05.

Results: ILC was significantly longer in stroke survivors with a subcortical lesion than in those with a cortical lesion for both bolus consistencies. However, there were no significant differences between the 2 groups in LCD. Stroke survivors with a subcortical lesion had a greater incidence of penetration or aspiration and silent aspiration than those with a cortical lesion and a longer delay in the ILC.

Conclusions: Subcortical lesions may put these survivors at greater risk of aspiration due to delayed initial laryngeal closure and reduced oral and laryngeal sensation. The subcortical damage, which occurs at the basal ganglia, may interrupt the ILC.
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http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2017.04.003DOI Listing
August 2017

A fluorogenic molecular nanoprobe with an engineered internal environment for sensitive and selective detection of biological hydrogen sulfide.

Chem Commun (Camb) 2017 Feb;53(14):2275-2278

Center for Theragnosis, Korea Institute of Science and Technology (KIST), 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791, Korea.

A nanoreactor approach based on the amphiphilic assembly of various molecules offers a chance to finely engineer the internal reaction medium to enable highly selective and sensitive detection of HS in biological media, being useful for microscopic imaging of cellular processes and in vitro diagnostics with blood samples.
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http://dx.doi.org/10.1039/c6cc09696dDOI Listing
February 2017

Vision/INS Integrated Navigation System for Poor Vision Navigation Environments.

Sensors (Basel) 2016 Oct 12;16(10). Epub 2016 Oct 12.

Department of Electronics Engineering, Chungnam National University, Daejon 34134, Korea.

In order to improve the performance of an inertial navigation system, many aiding sensors can be used. Among these aiding sensors, a vision sensor is of particular note due to its benefits in terms of weight, cost, and power consumption. This paper proposes an inertial and vision integrated navigation method for poor vision navigation environments. The proposed method uses focal plane measurements of landmarks in order to provide position, velocity and attitude outputs even when the number of landmarks on the focal plane is not enough for navigation. In order to verify the proposed method, computer simulations and van tests are carried out. The results show that the proposed method gives accurate and reliable position, velocity and attitude outputs when the number of landmarks is insufficient.
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http://dx.doi.org/10.3390/s16101672DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5087460PMC
October 2016

Congestion estimation technique in the optical network unit registration process.

Opt Lett 2016 Jul;41(13):2923-6

We present a congestion estimation technique (CET) to estimate the optical network unit (ONU) registration success ratio for the ONU registration process in passive optical networks. An optical line terminal (OLT) estimates the number of collided ONUs via the proposed scheme during the serial number state. The OLT can obtain congestion level among ONUs to be registered such that this information may be exploited to change the size of a quiet window to decrease the collision probability. We verified the efficiency of the proposed method through simulation and experimental results.
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http://dx.doi.org/10.1364/OL.41.002923DOI Listing
July 2016

Effects of tongue pressing effortful swallow in older healthy individuals.

Arch Gerontol Geriatr 2016 Sep-Oct;66:127-33. Epub 2016 Jun 3.

Communication Sciences and Disorders, Ohio University, Athens, OH 45701-2979, USA. Electronic address:

Introduction: The risk of swallowing disorders is increased for older individuals due to weak tongue and pharyngeal muscle strength. This study was appraised the value of a preventative approach by developing the tongue pressing effortful swallow (TPES) applied using a home-based and self-administered procedure. The TPES was developed by combining two swallowing exercises: tongue strengthening exercise and the effortful swallow. The purpose of this study was to examine the effects of the TPES on maximum tongue pressure and peak amplitude of submental muscle activity in older individuals.

Material And Methods: 27 older individuals (mean 73 years) performed a 4-week TPES. The exercise program was adapted to a home-based and self-administered procedure. The maximum tongue pressure was measured by the Iowa Oral Performance Instrument and peak amplitude of submental muscle activity by surface electromyography (sEMG). Statistical comparisons were made by a matched pairs t-test (p<0.05).

Results: The results of this study showed that the TPES had statistically significant and positive effects on increasing maximum tongue pressure, but the peak amplitude of the submental sEMG did not differ between before and after exercises.

Conclusions: The TPES had a positive impact in older individuals. The TPES, a combining exercise, was possible because two exercises had common physiological events. The TPES was a more innovative and efficient approach than the tongue strengthening exercise alone. In addition, older individuals were able to perform the swallowing exercise at home and by themselves with little assistance. Future research needs to refine the TPES and apply it to patients with dysphagia.
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http://dx.doi.org/10.1016/j.archger.2016.05.009DOI Listing
July 2017

Preparation of Fluorous Solvent-Dispersed Fe3O4 Nanocrystals: Role of Oxygen in Ligand Exchange.

Langmuir 2016 Apr 4;32(14):3348-53. Epub 2016 Apr 4.

Center for Theragnosis and ‡Center for Bionics, Korea Institute of Science and Technology (KIST) , 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea.

Perfluorinated ligand-passivated Fe3O4 nanocrystals were prepared through a biphasic ligand exchange method. It was found that dissolved oxygen in the reaction media predominantly determined the degree of ligand exchange and the resultant dispersion property of nanocrystals in a fluorous solvent. X-ray photoelectron spectroscopic analyses revealed that dissolved oxygen molecules bind to the surface iron species of nanocrystals in competition with the carboxylate moiety of ligands during the exchange reaction, lowering the degree of ligand exchange and colloidal stability significantly. Reducing the oxygen content of the fluorous phase by N2 bubbling was found to result in a highly stable dispersion of phase-transferred Fe3O4 nanocrystals with a single-particle size distribution maintained for a few months.
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http://dx.doi.org/10.1021/acs.langmuir.6b00526DOI Listing
April 2016

The Relation Between the Presence of Aspiration or Penetration and the Clinical Indicators of Dysphagia in Poststroke Survivors.

Ann Rehabil Med 2016 Feb 26;40(1):88-94. Epub 2016 Feb 26.

Communication Sciences and Disorders, Ohio University, Athens, OH, USA.

Objective: To examine the relation between the presence of penetration or aspiration and the occurrence of the clinical indicators of dysphagia. The presence of penetration or aspiration is closely related to the clinical indicators of dysphagia. It is essential to understand these relationships in order to implement proper diagnosis and treatment of dysphagia.

Methods: Fifty-eight poststroke survivors were divided into two groups: patients with or without penetration or aspiration. Medical records and videofluoroscopic swallowing examinations were reviewed. The occurrence of clinical indicators of dysphagia between two groups was analyzed with Cross Tabulation and the Pearson chi-square test (p<0.05).

Results: Poststroke survivors with penetration or aspiration had significantly high occurrences of delayed initiation of the swallow (p=0.04) and reduced hyolaryngeal elevation (p<0.01) than those without penetration or aspiration.

Conclusion: The results of this study indicate that delayed initiation of the swallow is a strong physiological indicator of penetration or aspiration during the oral stage of swallowing in poststroke survivors. For the pharyngeal stage of swallowing, hyoid and laryngeal elevation is a key event related to occurrence of penetration or aspiration. Clinical indicators should be investigated further to allow appropriate implementation of treatment strategies for stroke survivors.
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http://dx.doi.org/10.5535/arm.2016.40.1.88DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4775763PMC
February 2016

Development of highly efficient nanocarrier-mediated delivery approaches for cancer therapy.

Cancer Lett 2016 Apr 6;374(1):31-43. Epub 2016 Feb 6.

Center for Theragnosis, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791, Republic of Korea. Electronic address:

Nanocarriers (NCs) are a group of nano-sized vehicles devised to deliver drugs to targeted malignant tissues or organs that provide remarkably improved targeting efficiency and therapeutic efficacy for cancer therapy. A variety of NCs have been developed to accommodate appropriate loading and release of drugs with a wide spectrum of chemical and physical characteristics. In addition, physicochemical modifications to the surface or interior of NCs allow for modulation of pharmacokinetic features reflecting clinical demands. However, cancer-related mortality is still high and drug-mediated cancer treatment remains a challenging research field despite the remarkable advances in targeting efficiency and therapeutic efficacy resulting from NCs. In this review, we focus on typical approaches and recent trends in NC-mediated drug delivery systems and their potential for targeted cancer therapy.
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http://dx.doi.org/10.1016/j.canlet.2016.01.050DOI Listing
April 2016

Rational design for enhancing inflammation-responsive in vivo chemiluminescence via nanophotonic energy relay to near-infrared AIE-active conjugated polymer.

Biomaterials 2016 Apr 19;84:111-118. Epub 2016 Jan 19.

Center for Theragnosis, Korea Institute of Science and Technology (KIST), 39-1, Hawolgok-dong, Seongbuk-gu, Seoul 136-791, Republic of Korea. Electronic address:

H2O2-specific peroxalate chemiluminescence is recognized as a potential signal for sensitive in vivo imaging of inflammation but the effect of underlying peroxalate-emitter energetics on its efficiency has rarely been understood. Here we report a simple nanophotonic way of boosting near-infrared chemiluminescence with no need of complicated structural design and synthesis of an energetically favored emitter. The signal enhancement was attained from the construction of a nanoparticle imaging probe (∼26 nm in size) by dense nanointegration of multiple molecules possessing unique photonic features, i.e., i) a peroxalate as a chemical fuel generating electronic excitation energy in response to inflammatory H2O2, ii) a low-bandgap conjugated polymer as a bright near-infrared emitter showing aggregation-induced emission (AIE), and iii) an energy gap-bridging photonic molecule that relays the chemically generated excitation energy to the emitter for its efficient excitation. From static and kinetic spectroscopic studies, a green-emissive BODIPY dye has proven to be an efficient relay molecule to bridge the energy gap between the AIE polymer and the chemically generated excited intermediate of H2O2-reacted peroxalates. The energy-relayed nanointegration of AIE polymer and peroxalate in water showed a 50-times boosted sensing signal compared to their dissolved mixture in THF. Besides the high H2O2 detectability down to 10(-9) M, the boosted chemiluminescence presented a fairly high tissue penetration depth (>12 mm) in an ex vivo condition, which enabled deep imaging of inflammatory H2O2 in a hair-covered mouse model of peritonitis.
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http://dx.doi.org/10.1016/j.biomaterials.2016.01.038DOI Listing
April 2016

Fluorogenic nanoreactor assembly with boosted sensing kinetics for timely imaging of cellular hydrogen peroxide.

Chem Commun (Camb) 2016 Jan;52(6):1131-4

Center for Theragnosis, Korea Institute of Science and Technology (KIST), 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791, Korea.

The precise detection of endogenous H2O2 has been considered to be a useful tool for understanding cell physiology. Here, we have developed a nanoreactor co-incorporated with a H2O2-responsive fluorogenic molecule and a catalytic additive. The fast sensing kinetics allows us to visualize a subcellular response in real-time.
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http://dx.doi.org/10.1039/c5cc06387fDOI Listing
January 2016

Rich Pinch: Perception of Object Movement with Tactile Illusion.

IEEE Trans Haptics 2016 Jan-Mar;9(1):80-89. Epub 2015 Sep 1.

Vibrotactile feedback is an effective and economical approach for enriching interactive feedback. However, its effects are mostly limited to providing supplementary alarms or conveying the sense of simple object presence or contact. In this paper, we propose a novel tactile feedback method, called Rich Pinch, based on the "out of body" tactile illusion for selecting and manipulating a virtual object using a two-finger pinch gesture. Rich Pinch uses vibration motors attached only to the two fingertips, but can induce illusory feedback, such as tactile touch/contact and directional movement, as felt from the space between the fingers. We first experimentally verify that the "out of body" illusion technique does in fact exist when applied between the fingertips. Then, we compare three different tactile rendering functions to illustrate different resulting perceptual scales and argue to use the tangent-based interpolation in its actual application for a better user performance and experience due to its near-linear perceptual response. Finally, we assess the user experience (focusing on the perception of the object movement of the selected object) of the proposed pinch method by comparing it to the conventional contact-based method. Our results indicate that, with Rich Pinch, users were able to perceive rich dynamic feedback, and clearly preferred it over the conventional method.
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http://dx.doi.org/10.1109/TOH.2015.2475271DOI Listing
September 2015

Estimation and mitigation of N2O emission and nitrate leaching from intensive crop cultivation in the Haean catchment, South Korea.

Sci Total Environ 2015 Oct 22;529:40-53. Epub 2015 May 22.

Institute of Meteorology and Climate Research (IMK-IFU), Karlsruhe Institute of Technology, 82467 Garmisch-Partenkirchen, Germany. Electronic address:

Considering intensive agricultural management practices and environmental conditions, the LandscapeDNDC model was applied for simulation of yields, N2O emission and nitrate leaching from major upland crops and temperate deciduous forest of the Haean catchment, South Korea. Fertilization rates were high (up to 314 kg N ha(-1) year(-1)) and resulted in simulated direct N2O emissions from potato, radish, soybean and cabbage fields of 1.9 and 2.1 kg N ha(-1) year(-1) in 2009 and 2010, respectively. Nitrate leaching was identified as the dominant pathway of N losses in the Haean catchment with mean annual rates of 112.2 and 125.4 kg N ha(-1) year(-1), causing threats to water quality and leading to substantial indirect N2O emissions of 0.84 and 0.94 kg N ha(-1) year(-1) in 2009 and 2010 as estimates by applying the IPCC EF5. Simulated N2O emissions from temperate deciduous forest were low (approx. 0.50 kg N ha(-1) year(-1)) and predicted nitrate leaching rates were even negligible (≤0.01 kg N ha(-1) year(-1)). On catchment scale more than 50% of the total N2O emissions and up to 75% of nitrate leaching originated from fertilized upland fields, only covering 24% of the catchment area. Taking into account area coverage of simulated upland crops and other land uses these numbers agree well with nitrate loads calculated from discharge and concentration measurements at the catchment outlet. The change of current agricultural management practices showed a high potential of reducing N2O emission and nitrate leaching while maintaining current crop yields. Reducing (39%) and splitting N fertilizer application into 3 times was most effective and lead to about 54% and 77% reducing of N2O emission and nitrate leaching from the Haean catchment, the latter potentially contributing to improved water quality in the Soyang River Dam, which is the major source of drinking water for metropolitan residents.
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http://dx.doi.org/10.1016/j.scitotenv.2015.04.098DOI Listing
October 2015

Upper esophageal sphincter opening during swallow in stroke survivors.

Am J Phys Med Rehabil 2015 Sep;94(9):734-9

From the Communication Sciences and Disorders, Ohio University, Athens (YK, TP); Department of Speech Pathology and Audiology, Calvin College, Grand Rapids, Michigan (EO); and College of Health Sciences, Appalachian State University, Boone, North Carolina (GM).

Objective: Timely and efficient upper esophageal sphincter (UES) opening may be critical to safe transport of food or liquid to the stomach and to prevent aspiration during the swallow. The purpose of this study was to examine the temporal and biomechanical characteristics of the UES opening in stroke survivors.

Method: Maximum duration and width of the UES opening were obtained from 15 stroke survivors with aspiration and 15 stroke survivors with no aspiration. The control group was composed of 15 normal subjects undergoing videofluoroscopic swallowing examinations. The videofluoroscopic swallowing examination protocol was as follows: two swallows of 5 ml thin liquid and two swallows of 10 ml thin liquid. Statistical comparisons were made by repeated measurements of analysis of variance, and the significance level was set at P < 0.025.

Result: The stroke survivors with aspiration, the stroke survivors without aspiration, and the control group differed significantly for duration of UES opening (P < 0.01) but not maximum width of UES opening.

Conclusion: Prolonged UES opening may be related to prolonged pharyngeal transition of the bolus and slower UES muscle contraction and hyolaryngeal excursion after stroke.
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http://dx.doi.org/10.1097/PHM.0000000000000258DOI Listing
September 2015

Immunogenicity and efficacy of flagellin-envelope fusion dengue vaccines in mice and monkeys.

Clin Vaccine Immunol 2015 May 11;22(5):516-25. Epub 2015 Mar 11.

VaxInnate Corporation, Cranbury, New Jersey, USA.

The envelope (E) protein of flaviviruses includes three domains, EI, EII, and EIII, and is the major protective antigen. Because EIII is rich in type-specific and subcomplex-specific neutralizing epitopes and is easy to express, it is particularly attractive as a recombinant vaccine antigen. VaxInnate has developed a vaccine platform that genetically links vaccine antigens to bacterial flagellin, a Toll-like receptor 5 ligand. Here we report that tetravalent dengue vaccines (TDVs) consisting of four constructs, each containing two copies of EIII fused to flagellin (R3.2x format), elicited robust and long-lived neutralizing antibodies (geometric mean titers of 200 to 3,000), as measured with a 50% focus reduction neutralization test (FRNT50). In an immunogenicity study, rhesus macaques (n = 2) immunized subcutaneously with 10 μg or 90 μg of TDV three or four times, at 4- to 6-week intervals, developed neutralizing antibodies to four dengue virus (DENV) serotypes (mean post-dose 3 FRNT50 titers of 102 to 601). In an efficacy study, rhesus macaques (n = 4) were immunized intramuscularly with 16 μg or 48 μg of TDV or a placebo control three times, at 1-month intervals. The animals that received 48-μg doses of TDV developed neutralizing antibodies against the four serotypes (geometric mean titers of 49 to 258) and exhibited reduced viremia after DENV-2 challenge, with a group mean viremia duration of 1.25 days and 2 of 4 animals being completely protected, compared to the placebo-treated animals, which all developed viremia, with a mean duration of 4 days. In conclusion, flagellin-EIII fusion vaccines are immunogenic and partially protective in a nonhuman primate model.
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http://dx.doi.org/10.1128/CVI.00770-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4412944PMC
May 2015

Serum-stable quantum dot-protein hybrid nanocapsules for optical bio-imaging.

Nanotechnology 2014 May 10;25(17):175702. Epub 2014 Apr 10.

Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.

We introduce shell cross-linked protein/quantum dot (QD) hybrid nanocapsules as a serum-stable systemic delivery nanocarrier for tumor-targeted in vivo bio-imaging applications. Highly luminescent, heavy-metal-free Cu0.3InS2/ZnS (CIS/ZnS) core-shell QDs are synthesized and mixed with amine-reactive six-armed poly(ethylene glycol) (PEG) in dichloromethane. Emulsification in an aqueous solution containing human serum albumin (HSA) results in shell cross-linked nanocapsules incorporating CIS/ZnS QDs, exhibiting high luminescence and excellent dispersion stability in a serum-containing medium. Folic acid is introduced as a tumor-targeting ligand. The feasibility of tumor-targeted in vivo bio-imaging is demonstrated by measuring the fluorescence intensity of several major organs and tumor tissue after an intravenous tail vein injection of the nanocapsules into nude mice. The cytotoxicity of the QD-loaded HSA-PEG nanocapsules is also examined in several types of cells. Our results show that the cellular uptake of the QDs is critical for cytotoxicity. Moreover, a significantly lower level of cell death is observed in the CIS/ZnS QDs compared to nanocapsules loaded with cadmium-based QDs. This study suggests that the systemic tumor targeting of heavy-metal-free QDs using shell cross-linked HSA-PEG hybrid nanocapsules is a promising route for in vivo tumor diagnosis with reduced non-specific toxicity.
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http://dx.doi.org/10.1088/0957-4484/25/17/175702DOI Listing
May 2014

Ligand-independent interaction of the type I interferon receptor complex is necessary to observe its biological activity.

Cytokine 2013 Oct 3;64(1):286-97. Epub 2013 Jul 3.

Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, The University of Medicine and Dentistry of New Jersey, 675 Hoes Lane West, Piscataway, NJ 08855, USA. Electronic address:

Ectopic coexpression of the two chains of the Type I and Type III interferon (IFN) receptor complexes (IFN-αR1 and IFN-αR2c, or IFN-λR1 and IL-10R2) yielded sensitivity to IFN-alpha or IFN-lambda in only some cells. We found that IFN-αR1 and IFN-αR2c exhibit FRET only when expressed at equivalent and low levels. Expanded clonal cell lines expressing both IFN-αR1 and IFN-αR2c were sensitive to IFN-alpha only when IFN-αR1 and IFN-αR2c exhibited FRET in the absence of human IFN-alpha. Coexpression of RACK-1 or Jak1 enhanced the affinity of the interaction between IFN-αR1 and IFN-αR2c. Both IFN-αR1 and IFN-αR2c exhibited FRET with Jak1 and Tyk2. Together with data showing that disruption of the preassociation between the IFN-gamma receptor chains inhibited its biological activity, we propose that biologically active IFN receptors require ligand-independent juxtaposition of IFN receptor chains assisted by their associated cytosolic proteins.
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http://dx.doi.org/10.1016/j.cyto.2013.06.309DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3770802PMC
October 2013
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