Publications by authors named "Ho Young Kim"

171 Publications

Optimal aerobic exercise intensity and its influence on the effectiveness of exercise therapy in patients with pulmonary arterial hypertension: a systematic review.

J Thorac Dis 2021 Jul;13(7):4530-4540

Division of Cardiology, Department of Internal Medicine, Rehabilitation & Prevention Center, Heart Stroke & Vascular Institute, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea.

Background: Exercise intensity in exercise training programs is an important determinant of program efficacy, such as improvement in exercise capacity and quality of life (QOL). It is not well known whether differently applied exercise intensities are efficacious when used in exercise-based cardiac rehabilitation programs for patients with pulmonary arterial hypertension (PAH).

Methods: Three databases (PubMed, EMBASE, and CINAHL) were searched with the following inclusion criteria: comparative study of exercise interventions for patients with pulmonary arterial hypertension. Three clinical specialists (a physician, nurse, and exercise physiologist) selected the included articles using the process of systematic review. Included articles were grouped according to aerobic exercise intensity: low, moderate-to-vigorous, and vigorous. The level of evidence for each study was rated using Sackett's levels of evidence.

Results: Of 1,452 studies reviewed, 8 were included according to the inclusion criteria (3 randomized controlled trials (RCTs), 3 prospective studies, and 2 case series). Exercise capacity for a six-minute walk distance (mean: 57.7 m) and QOL improved in the above moderate intensity group, while the low intensity group did not show improvement after intervention. For termination criteria, data obtained from the reviewed articles were not sufficient to suggest any exercise intensity recommendations for patients with pulmonary arterial hypertension.

Discussion: The findings in this study suggest that at least moderate aerobic exercise intensity is needed to significantly improve six-minute walk distance and QOL in individuals diagnosed with World Health Organization Group 1 of pulmonary arterial hypertension. There is a need for prospective RCTs comparing different exercise intensities in this patient population.
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http://dx.doi.org/10.21037/jtd-20-3296DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8339761PMC
July 2021

Treatment and Outcomes of Metastatic Pancreatic Cancer in Elderly Patients.

Chemotherapy 2021 Aug 4:1-6. Epub 2021 Aug 4.

Department of Internal Medicine, Hallym University Medical Center, Hallym University College of Medicine, Hwaseong-si, Republic of Korea.

Background And Aims: Although pancreatic cancers are common in older age-groups, the prognosis remains poor due to limited studies on treatment approaches and outcomes in a given population. We aimed to examine treatment patterns and their outcomes in older patients with metastatic pancreatic cancer in a real-world context.

Materials And Methods: We conducted a retrospective study including 167 patients with metastatic pancreatic cancer (aged ≥70 years and male/female: 78/89) between January 2010 and July 2015. Patients' retrieved data from medical records were analyzed according to treatment types, followed by a review of clinicopathologic variables and treatment outcomes.

Results: Of the 167 eligible patients for the study, only 21.6% (n = 36) received palliative chemotherapy. The median age of the chemotherapy group was 74.0 years and 78.6 years for the supportive care group. The median survival of the chemotherapy group was 9.2 months (range: 1.0-24.9 months), compared with that of the supportive care group, which was 2.3 months (range: 0.1-31.8 months). Among the patients in the chemotherapy group, 50% (n = 18) received gemcitabine-based double therapy, and 30% patients (n = 9) received second-line chemotherapy.

Conclusions: Our results showed that older patients with metastatic pancreatic cancer were less likely to receive chemotherapy. However, the survival benefit from chemotherapy was comparable to that of younger patients' counterpart. Thus, further study involving identification of older patients who would benefit from cytotoxic chemotherapy is needed.
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http://dx.doi.org/10.1159/000517245DOI Listing
August 2021

Agile reversible shape-morphing of particle rafts.

Soft Matter 2021 Aug 2;17(32):7554-7564. Epub 2021 Aug 2.

Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea.

Materials that transform shapes responding to external stimuli can bring unprecedented innovations to soft matter physics, soft robotics, wearable electronics, and architecture. As most conventional soft actuation technologies induce large deformations only in a preprogrammed manner at designated locations, the material systems capable of agile reversible deformations without prescribed patterns are strongly desired for versatile mechanical morphing systems. Here we report a morphable liquid interface coated with dielectric particles, or a particle raft, which can reversibly change its topography under an external electric field. The rafts change from flat floors to towers within seconds, and the morphed structures are even capable of horizontal translation. Our experiments and theory show that the raft deformation is driven by electrostatic attraction between particles and electrodes, while being modulated by electric discharge. A broad range of materials serving as electrodes, e.g., human fingers and transparent polymers, suggests this system's diverse applications, including the human-machine interface and the three-dimensional physical display.
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http://dx.doi.org/10.1039/d1sm00564bDOI Listing
August 2021

Conformation-modulated three-dimensional electrocatalysts for high-performance fuel cell electrodes.

Sci Adv 2021 Jul 21;7(30). Epub 2021 Jul 21.

Center for Hydrogen and Fuel Cell Research, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea.

Unsupported Pt electrocatalysts demonstrate excellent electrochemical stability when used in polymer electrolyte membrane fuel cells; however, their extreme thinness and low porosity result in insufficient surface area and high mass transfer resistance. Here, we introduce three-dimensionally (3D) customized, multiscale Pt nanoarchitectures (PtNAs) composed of dense and narrow (for sufficient active sites) and sparse (for improved mass transfer) nanoscale building blocks. The 3D-multiscale PtNA fabricated by ultrahigh-resolution nanotransfer printing exhibited excellent performance (45% enhanced maximum power density) and high durability (only 5% loss of surface area for 5000 cycles) compared to commercial Pt/C. We also theoretically elucidate the relationship between the 3D structures and cell performance using computational fluid dynamics. We expect that the structure-controlled 3D electrocatalysts will introduce a new pathway to design and fabricate high-performance electrocatalysts for fuel cells, as well as various electrochemical devices that require the precision engineering of reaction surfaces and mass transfer.
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http://dx.doi.org/10.1126/sciadv.abe9083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8294758PMC
July 2021

Comparing cleaning effects of gas and vapor bubbles in ultrasonic fields.

Ultrason Sonochem 2021 Aug 6;76:105618. Epub 2021 Jun 6.

Department of Mechanical Engineering, Sogang University, Seoul 04107, South Korea; Institute of Emergent Materials, Sogang University, Seoul 04107, South Korea. Electronic address:

The dynamic actions of cavitation bubbles in ultrasonic fields can clean surfaces. Gas and vapor cavitation bubbles exhibit different dynamic behaviors in ultrasonic fields, yet little attention has been given to the distinctive cleaning effects of gas and vapor bubbles. We present an experimental investigation of surface cleaning by gas and vapor bubbles in an ultrasonic field. Using high-speed videography, we found that the primary motions of gas and vapor bubbles responsible for surface cleaning differ. Our cleaning tests under different contamination conditions in terms of contaminant adhesion strength and surface wettability reveal that vapor and gas bubbles are more effective at removing contaminants with strong and weak adhesion, respectively, and furthermore that hydrophobic substrates are better cleaned by vapor bubbles. Our study not only provides a better physical understanding of the ultrasonic cleaning process, but also proposes novel techniques to improve ultrasonic cleaning by selectively employing gas and vapor bubbles depending on the characteristics of the surface to be cleaned.
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http://dx.doi.org/10.1016/j.ultsonch.2021.105618DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8207306PMC
August 2021

Coalescence of oil drops and films on micropillared substrates enabled by enhanced water drainage through pillar gaps.

Soft Matter 2021 Jun 24;17(24):5888-5896. Epub 2021 May 24.

Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea.

Collecting or removing oil drops dispersed in water is essential in a range of industrial processes including oil recovery and oil spill cleanup. However, it is by no means easy to induce merging of oil drops with another body of oil due to slow drainage of the intervening water film. Here, we report immediate coalescence of oil drops with oil films that lie on micropillar arrays as immersed in various aqueous solutions. In addition to experimental demonstrations, we theoretically construct a regime map to predict whether the drop will bounce off or coalesce with the oil film, which is determined by the oil film thickness, geometry of the pillar array and liquid properties. Good agreement between theory and experiment indicates that micropillar arrays provide additional drainage paths of the intervening film, which helps drop-film coalescence. Our results suggest potential implications of utilizing oil-laden microporous structures to achieve efficient demulsification of oil drops in contaminated water.
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http://dx.doi.org/10.1039/d1sm00375eDOI Listing
June 2021

Cutaneous Plasmacytosis Showing a Neuronal Involvement in a 35-Year-Old Female.

Ann Dermatol 2020 Apr 11;32(2):174-176. Epub 2020 Mar 11.

Department of Dermatology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.

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http://dx.doi.org/10.5021/ad.2020.32.2.174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7992543PMC
April 2020

Validity of Diagnostic Codes for Identification of Psoriasis Patients in Korea.

Ann Dermatol 2020 Apr 11;32(2):115-121. Epub 2020 Mar 11.

Department of Dermatology, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea.

Background: Recently, the number of nationwide medical researches on psoriasis using the National Health Insurance Service database has been on the rise. However, identification of psoriasis using diagnostic codes alone can lead to misclassification. Accuracy of the diagnostic codes and their concordance with medical records should be validated first to identify psoriasis patients correctly.

Objective: To validate the diagnostic codes of psoriasis (International Classification of Diseases, 10th Revision L40) and to find the algorithm for the identification of psoriasis.

Methods: We collected medical records of patients who received their first diagnostic codes of psoriasis during 5 years from five hospitals. Fifteen percent of psoriasis patients were randomly selected from each hospital. We performed a validation by reviewing medical records and compared 5 algorithms to identify the best algorithm.

Results: Total of 538 cases were reviewed and classified as psoriasis (n=368), not psoriasis (n=159), and questionable (n=11). The most accurate algorithm was including patients with ≥1 visits with psoriasis as primary diagnostic codes and prescription of vitamin D derivatives. Its positive predictive value was 96.5% (95% confidence interval [CI], 93.9%~98.1%), which was significantly higher than those of the algorithm, including patients with ≥1 visits with psoriasis as primary diagnostic codes or including ≥1 visits with diagnostic codes of psoriasis (primary or additional) (91.0% and 69.8%). Sensitivity was 90.8% (95% CI, 87.2%~93.4%) and specificity was 92.5% (95% CI, 86.9%~95.9%).

Conclusion: Our study demonstrates a validated algorithm to identify psoriasis, which will be useful for the nationwide population-based study of psoriasis in Korea.
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http://dx.doi.org/10.5021/ad.2020.32.2.115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7992553PMC
April 2020

Prognostic effects of cytokine levels on patients treated with taxane and zoledronic acid for metastatic breast cancer in bone (BEAT-ZO) (KCSG BR 10-13).

Cytokine 2021 06 23;142:155487. Epub 2021 Mar 23.

Korea University Anam Hospital, Seoul, Republic of Korea.

Advanced breast cancer frequently metastasizes to the skeleton causing major mobility issues and hazards to quality of life. To manage osteolytic bone metastasis, bone-modifying agents and chemotherapy are recommended as the standard of care. Here, we investigated serologic biomarkers that might be associated with prognosis in breast cancer patients treated with zoledronic acid (ZA) and taxane-based chemotherapy. We collected serum samples from breast cancer patients with bone metastasis who received taxane plus ZA as palliative treatment. Fourteen biomarkers of angiogenesis, immunogenicity, and apoptosis were assessed, and the correlation between serum cytokine levels and patient's prognosis was statistically analyzed. Sixty-six patients were enrolled, and samples from 40 patients were analyzed after laboratory quality control. Patients with low baseline PDGF-AA, high IFN-γ, low MCP-2, low TGF-β1, and low TNF-α were significantly associated with longer progression-free survival (PFS). Decreasing VEGF and TNF-α and increasing FGF-2 and PDGF-AA in the early treatment phase indicated longer PFS. In univariate and multivariate analyses, low TGF-β1 and TNF-α and high IFN-γ at baseline were associated with a significantly low hazard ratio for disease progression. Further, we designed a risk score with TGF-β1, TNF-α, and IFN-γ levels, which could prognosticate patients for PFS. In conclusion, serum cytokine level, such as TGF-β1, TNF-α, and IFN-γ, could be a potential prognostic biomarker for breast cancer patients with bone metastasis treated with ZA and taxane-based chemotherapy.
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http://dx.doi.org/10.1016/j.cyto.2021.155487DOI Listing
June 2021

Scalable High-Efficiency Bi-Facial Solar Evaporator with a Dendritic Copper Oxide Wick.

ACS Appl Mater Interfaces 2021 Mar 4;13(10):11869-11878. Epub 2021 Mar 4.

Department of Mechanical Engineering, Seoul National University, Seoul 08826, Republic of Korea.

Solar thermal distillation is a promising way to harvest clean water due to its sustainability. However, the energy density of solar irradiation inevitably demands scalability of the systems. To realize practical applications, it is highly desirable to fabricate meter-scale solar evaporator panels with high capillary performance as well as optical absorptance using scalable and high-throughput fabrication methods. Here, we demonstrate a truly scalable fabrication process for a bi-facial solar evaporator with copper oxide dendrites via the hydrogen bubble templated electrochemical deposition technique. Furthermore, we construct a theoretical model combining capillarity and evaporative mass transfer, which leads to optimal operation conditions and wick characteristics, including superhydrophilicity, extreme capillary performance, and omni-angular high optical absorptance. The fabricated porous surfaces with excellent capillary performance and productivity provide a pathway toward a highly efficient bi-facial solar evaporator panel with meter-level scalability.
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http://dx.doi.org/10.1021/acsami.0c21570DOI Listing
March 2021

Erratum to "BRAF and NRAS mutations and antitumor immunity in Korean malignant melanomas and their prognostic relevance: Gene set enrichment analysis and CIBERSORT analysis" [Pathol. Res. Pract. 215 (12) (2019) 152671].

Pathol Res Pract 2021 Mar 19;219:153316. Epub 2021 Feb 19.

Department of Hematological Oncology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, 22, Gwanpyeong-ro 170beon-gil, Dongan-gu, Anyang-si, Gyeonggi-do, 14068, Republic of Korea.

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http://dx.doi.org/10.1016/j.prp.2020.153316DOI Listing
March 2021

Avian mud nest architecture by self-secreted saliva.

Proc Natl Acad Sci U S A 2021 01;118(3)

Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea;

Mud nests built by swallows (Hirundinidae) and phoebes () are stable granular piles attached to cliffs, walls, or ceilings. Although these birds have been observed to mix saliva with incohesive mud granules, how such biopolymer solutions provide the nest with sufficient strength to support the weight of the residents as well as its own remains elusive. Here, we elucidate the mechanism of strong granular cohesion by the viscoelastic paste of bird saliva through a combination of theoretical analysis and experimental measurements in both natural and artificial nests. Our mathematical model considering the mechanics of mud nest construction allows us to explain the biological observation that all mud-nesting bird species should be lightweight.
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http://dx.doi.org/10.1073/pnas.2018509118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7826398PMC
January 2021

Awareness and Use of Complementary and Alternative Medicine in Korean Lung Cancer Patients.

Tuberc Respir Dis (Seoul) 2021 Apr 8;84(2):105-114. Epub 2020 Dec 8.

Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Republic of Korea.

Background: Complementary and alternative medicine (CAM) has been used frequently, and its use continues to increase in lung cancer patients, despite insufficient scientific of its efficacy. To investigate this situation, we analyzed the current awareness and use of CAM in Korean lung-cancer patients.

Methods: This prospective survey-based study was performed at seven medical centers in South Korea between August and October 2019. The survey assessed general patient characteristics and the awareness and use of CAM. We analyzed differences in the clinical parameters of patients aware and not aware of CAM and of CAM non-users and users.

Results: Of the 434 patients included in this study, 68.8% responded that they were aware of CAM and 30.9% said they had experienced it. In univariate analysis, the patients aware of CAM were younger with poor performance status, had advanced-stage lung cancer, received more systemic therapy, and received concurrent chemoradiation therapy (CCRT). By multiple logistic regression, younger age, poor performance status, advanced stage, and prior CCRT were identified as independent risk factors for CAM awareness. There were no significant differences in the general characteristics and cancer-associated clinical parameters of CAM non-users and users.

Conclusion: Specific clinical parameters were associated with patients' awareness of CAM, although there were no significantly different characteristics between CAM users and non-users.
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http://dx.doi.org/10.4046/trd.2020.0098DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8010414PMC
April 2021

Direct recovery of spilled oil using hierarchically porous oil scoop with capillary-induced anti-oil-fouling.

J Hazard Mater 2021 05 18;410:124549. Epub 2020 Nov 18.

Materials and Life Science Research Division, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea. Electronic address:

The pitcher plant has evolved its hierarchically grooved peristome to enhance a water-based slippery system for capturing insects with oil-covered footpads. Based on this, we proposed a hierarchically porous oil scoop (HPOS) with capillary-induced oil peel-off ability for repeatable spilled oil recovery. As the HPOS scoops oil-water mixture, water passes through the hole while the oil is confined within a curved geometry. The filter in HPOS has three levels of porous structures; (1) 3D-printed mesh structure with sub-millimeter scale hole to filter out oil from an oil-water mixture, (2) internal micropore in fibers enhancing capillarity and water transport, (3) O plasma-induced high-aspect-ratio nanopillar structures imposing anti-oil-fouling property with capillary-induced oil peeling. As the oil-contaminated HPOS makes contact with water, water meniscus rises and peels off the oil immediately at the air-water interface. The oil-peel-off ability of the HPOS would prevent pores from clogging by oils for reuse. The study demonstrated that the HPOS recovers highly viscous oil (up to 5000 mm·s) with a high recovery rate (>95%), leaving the filtered water with low oil content (<10 ppm), which satisfies the discharge criterion of 15 ppm.
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http://dx.doi.org/10.1016/j.jhazmat.2020.124549DOI Listing
May 2021

A Case of Eosinophilic Pustular Folliculitis Associated With Herpes Zoster.

Am J Dermatopathol 2021 Apr;43(4):298-299

Department of Dermatology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Republic of Korea.

Abstract: Patients with eosinophilic pustular folliculitis (EPF), a sterile eosinophilic infiltration of hair follicles, often present with papulopustules that tend to form annular plaques. Histopathologic examination revealed eosinophilic infiltration around the pilosebaceous units and eosinophilic microabscess formation. Although the pathogenesis of EPF is unknown, T-helper type 2 immune responses were suggested to be important based on their stimulating effect on the sebaceous glands. Here, we report the first case of EPF associated with herpes zoster, indicating that herpes zoster and EPF are correlated with T-helper type 2 immune responses.
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http://dx.doi.org/10.1097/DAD.0000000000001818DOI Listing
April 2021

The 2020 revision of the guidelines for the management of myeloproliferative neoplasms.

Korean J Intern Med 2021 01 4;36(1):45-62. Epub 2020 Dec 4.

Division of Hematology-Oncology, Department of Internal Medicine, Korea University Guro Hospital, Seoul, Korea.

In 2016, the World Health Organization revised the diagnostic criteria for myeloproliferative neoplasms (MPNs) based on the discovery of disease-driving genetic aberrations and extensive analysis of the clinical characteristics of patients with MPNs. Recent studies have suggested that additional somatic mutations have a clinical impact on the prognosis of patients harboring these genetic abnormalities. Treatment strategies have also advanced with the introduction of JAK inhibitors, one of which has been approved for the treatment of patients with myelofibrosis and those with hydroxyurea-resistant or intolerant polycythemia vera. Recently developed drugs aim to elicit hematologic responses, as well as symptomatic and molecular responses, and the response criteria were refined accordingly. Based on these changes, we have revised the guidelines and present the diagnosis, treatment, and risk stratification of MPNs encountered in Korea.
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http://dx.doi.org/10.3904/kjim.2020.319DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820646PMC
January 2021

Water strider females use individual experience to adjust jumping behaviour to their weight within physical constraints of water surface tension.

Sci Rep 2020 10 29;10(1):18657. Epub 2020 Oct 29.

Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, 08826, Korea.

Different species of water striders match leg speeds to their body sizes to maximize their jump take off velocity without breaking the water surface, which might have aided evolution of leg structures optimized for exploitation of the water surface tension. It is not understood how water striders achieve this match. Can individuals modify their leg movements based on their body mass and locomotor experience? Here we tested if water striders, Gerris latiabdominis, adjust jumping behaviour based on their personal experience and how an experimentally added body weight affects this process. Females, but not males, modified their jumping behaviour in weight-dependent manner, but only when they experienced frequent jumping. They did so within the environmental constraint set by the physics of water surface tension. Females' ability to adjust jumping may represent their adaptation to frequent increases or decreases of the weight that they support as mating bouts, during which males ride on top of females, start or end, respectively. This suggests that natural selection for optimized biomechanics combined with sexual selection for mating adaptations shapes this ability to optimally exploit water surface tension, which might have aided adaptive radiation of Gerromorpha into a diversity of semiaquatic niches.
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http://dx.doi.org/10.1038/s41598-020-75564-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7596521PMC
October 2020

Ionic spiderwebs.

Sci Robot 2020 07;5(44)

Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.

Spiders use adhesive, stretchable, and translucent webs to capture their prey. However, sustaining the capturing capability of these webs can be challenging because the webs inevitably invite contamination, thus reducing its adhesion force. To overcome these challenges, spiders have developed strategies of using webs to sense prey and clean contaminants. Here, we emulate the capturing strategies of a spider with a single pair of ionic threads based on electrostatics. Our ionic spiderwebs completed consecutive missions of cleaning contamination on itself, sensing approaching targets, capturing those targets, and releasing them. The ionic spiderwebs demonstrate the importance of learning from nature and push the boundaries of soft robotics in an attempt to combine mutually complementary functions into a single unit with a simple structure.
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http://dx.doi.org/10.1126/scirobotics.aaz5405DOI Listing
July 2020

Intermetallic PtCu Nanoframes as Efficient Oxygen Reduction Electrocatalysts.

Nano Lett 2020 Oct 22;20(10):7413-7421. Epub 2020 Sep 22.

School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea.

Nanoframe alloy structures represent a class of high-performance catalysts for the oxygen reduction reaction (ORR), owing to their high active surface area, efficient molecular accessibility, and nanoconfinement effect. However, structural and chemical instabilities of nanoframes remain an important challenge. Here, we report the synthesis of PtCu nanoframes constructed with an atomically ordered intermetallic structure (-PtCuNF/C) showing high ORR activity, durability, and chemical stability. We rationally designed the -PtCuNF/C catalyst by combining theoretical composition predictions with a silica-coating-mediated synthesis. The -PtCuNF/C combines intensified strain and ligand effects from the intermetallic PtCu L1 structure and advantages of the nanoframes, resulting in superior ORR activity to disordered alloy PtCu nanoframes (-PtCuNF/C) and commercial Pt/C catalysts. Importantly, the -PtCuNF/C showed the highest ORR mass activity among PtCu-based catalysts. Furthermore, the -PtCuNF/C exhibited higher ORR durability and far less etching of constituent atoms than -PtCuNF/C and Pt/C, attesting to the chemically stable nature of the intermetallic structure.
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http://dx.doi.org/10.1021/acs.nanolett.0c02812DOI Listing
October 2020

A Case of Multiple Tiny Osteolipomas on Face.

Am J Dermatopathol 2020 Nov;42(11):896-898

Department of Dermatology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Republic of Korea.

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http://dx.doi.org/10.1097/DAD.0000000000001680DOI Listing
November 2020

Crack density in bloodstains.

Soft Matter 2020 Jun;16(24):5571-5576

Department of Mechanical Engineering, Seoul National University, Seoul 08826, Republic of Korea.

We construct a theoretical framework to understand the crack density of bloodstains by modeling whole blood as a suspension of binary size colloid particles. Our analysis based upon theories of soft capillarity and porous flows explains the observed increase of the crack density with increase of blood viscosity and decrease of environmental humidity. The results have direct implications on forensic science and medical diagnosis.
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http://dx.doi.org/10.1039/d0sm00640hDOI Listing
June 2020

Trails of ants converge or diverge through lens-shaped impediments, resembling principles of optics.

Sci Rep 2020 05 21;10(1):8479. Epub 2020 May 21.

Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, 08826, South Korea.

Analogies across disciplines often indicate the existence of universal principles such as optimization, while the underlying proximate mechanisms may differ. It was reported recently that trails of ants refract at the border of substrates, on which walking speeds differ. This phenomenon is analogous to the travel-time-minimizing routes of light refracting at the borders between different media. Here, we further demonstrate that ant tracks converge or diverge across lens-shaped impediments similar to light rays through concave or convex optical lenses. The results suggest that the optical principle of travel time reduction may apply to ants. We propose a simple mathematical model that assumes nonlinear positive feedback in pheromone accumulation. It provides a possible explanation of the observed similarity between ant behavior and optics, and it is the first quantitative theoretical demonstration that pheromone-based proximate mechanisms of trail formation may produce this similarity. However, the future detailed empirical observations of ant behavior on impediment edges during the process of pheromone trail formation are needed in order to evaluate alternative explanations for this similarity.
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http://dx.doi.org/10.1038/s41598-020-65245-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7242390PMC
May 2020

Preparation of a multi-modal agent for sentinel lymph node mapping using Evans blue and Tc-labeled mannosylated human serum albumin conjugate.

Nucl Med Biol 2020 May - Jun;84-85:38-45. Epub 2020 Feb 4.

Department of Nuclear Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address:

Introduction: The identification of sentinel lymph nodes (SLNs) is important in deciding the resection range during surgery. Tc-labeled mannosylated human serum albumin ([Tc]Tc-MSA) is a radiopharmaceutical developed for SLN detection by targeting macrophages. Evans blue (EB) is a blue dye binding strongly to albumin and has been used for SLN detection. [Tc]Tc-MSA-EB conjugate was prepared as a multi-modal imaging agent and tested its performance by visual investigation, fluorescence imaging and SPECT/CT for SLN mapping in mice.

Methods: EB was mixed with various concentration of MSA to prepare MSA-EB conjugates. The binding efficiencies were determined using thin-layer chromatography. The UV-VIS spectra and molar extinction coefficient of the conjugate were obtained. The fluorescence was monitored at the excitation wavelength range 420-780 nm and the emission wavelength range 520-845 nm. The [Tc]Tc-MSA-EB conjugate and EB were injected into the footpads of normal BALB/c mice to check the lymph node (LN) uptakes. The visible, fluorescence, and SPECT/CT images were obtained after injection.

Results: The conjugation of EB with MSA increased by time and was saturated within 10 min. The molar extinction coefficient of the conjugate was 99,259.3/M/cm at 620 nm. The uptake of conjugate into the popliteal LN after injection into the footpads of mice was investigated visually and fluorescence imaging. SPECT/CT images showed that the standardized uptake values of [Tc]Tc-MSA-EB conjugate in popliteal LN were about 4 times higher than in sciatic LN at all timepoints. It was confirmed by investigating resected LN that the blue color, fluorescence, and radioactivity of the [Tc]Tc-MSA-EB conjugate were retained only on the LN and did not spread to adjoining tissues.

Conclusion: [Tc]Tc-MSA-EB conjugate has a great potential as a multi-modal SLN mapping agent which could be detected by visual investigation, fluorescence imaging, and SPECT/CT.
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http://dx.doi.org/10.1016/j.nucmedbio.2020.02.002DOI Listing
July 2021

Novel genes exhibiting DNA methylation alterations in Korean patients with chronic lymphocytic leukaemia: a methyl-CpG-binding domain sequencing study.

Sci Rep 2020 01 23;10(1):1085. Epub 2020 Jan 23.

Department of Laboratory Medicine, Hallym University Sacred Heart Hospital, Anyang, Republic of Korea.

Chronic lymphocytic leukaemia (CLL) exhibits differences between Asians and Caucasians in terms of incidence rate, age at onset, immunophenotype, and genetic profile. We performed genome-wide methylation profiling of CLL in an Asian cohort for the first time. Eight Korean patients without somatic immunoglobulin heavy chain gene hypermutations underwent methyl-CpG-binding domain sequencing (MBD-seq), as did five control subjects. Gene Ontology, pathway analysis, and network-based prioritization of differentially methylated genes were also performed. More regions were hypomethylated (2,062 windows) than were hypermethylated (777 windows). Promoters contained the highest proportion of differentially methylated regions (0.08%), while distal intergenic and intron regions contained the largest number of differentially methylated regions. Protein-coding genes were the most abundant, followed by long noncoding and short noncoding genes. The most significantly over-represented signalling pathways in the differentially methylated gene list included immune/cancer-related pathways and B-cell receptor signalling. Among the top 10 hub genes identified via network-based prioritization, four (UBC, GRB2, CREBBP, and GAB2) had no known relevance to CLL, while the other six (STAT3, PTPN6, SYK, STAT5B, XPO1, and ABL1) have previously been linked to CLL in Caucasians. As such, our analysis identified four novel candidate genes of potential significance to Asian patients with CLL.
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http://dx.doi.org/10.1038/s41598-020-57919-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6978354PMC
January 2020

Effect of Surface Roughness on Crystal Size of Manganese Phosphate Coating of Carbon Steel.

J Nanosci Nanotechnol 2020 07;20(7):4312-4317

Department of Metallurgical Engineering, College of Engineering, INHA University, Incheon, 22212, Republic of Korea.

In this study, the correlation between surface roughness of carbon steel and crystal size of manganese phosphate coatings has been investigated. The microstructure and surface morphology of the coatings were analyzed by SEM, XRD. The surface roughness test was carried out in order to calculate value by atomic force microscopy (AFM). Also, the tribology property of manganese phosphate coating was tested by ball-on disk. XRD showed that (Mn,Fe)H₂(PO₄)₄·4H₂O in manganese phosphate coating layer was formed by the chemical reaction between manganese phosphate and elements in carbon steel. Also, (Mn,Fe)H₂(PO₄)₄ · 4H₂O was observed to be formed in all manganese phosphate conversion coating. With regard to the effects of surface roughness on manganese phosphate coatings, it can be seen that there is an increase of the crystal size on manganese phosphate coating as the surface roughness of carbon steel decreased. The increase of crystal size by the surface roughness had effect on the tribology property and electrochemical property. It was approved that friction coefficient of manganese phosphate coating is remarkably improved as the surface roughness of carbon steel become rough.
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http://dx.doi.org/10.1166/jnn.2020.17551DOI Listing
July 2020

Highly Exfoliated and Functionalized Single-Walled Carbon Nanotubes as Fast-Charging, High-Capacity Cathodes for Rechargeable Lithium-Ion Batteries.

ACS Appl Mater Interfaces 2020 Jan 27;12(1):1322-1329. Epub 2019 Dec 27.

Nano Hybrid Technology Research Center, Electrical Materials Research Division , Korea Electrotechnology Research Institute (KERI) , Changwon 51543 , Republic of Korea.

Compared with traditional metal-oxide lithium-ion battery (LIB) cathodes, nanocarbon-based cathode materials have received much attention for potential application in LIBs because of their superior power density and long-term cyclability. However, their lithium-ion storage capacity needs further improvement for practical applications, and the trade-off between capacity and conductivity, when oxygen functional groups as lithium-ion storage sites are introduced to the nanocarbon materials, needs to be addressed. Here, we report a sequential oxidation-reduction process for the synthesis of single-walled carbon nanotubes (SWCNTs) for LIB cathodes with fast charging, long-term cyclability, and high gravimetric capacity. A LIB cathode based on highly exfoliated ( < 10 nm) and oxygen-functionalized single-walled carbon nanotubes is obtained via the modified Brodie's method using fuming nitric acid and a mild oxidant (B-SWCNTs). Post treatment including horn sonication and hydrogen thermal reduction developed surface defects and removed the unnecessary C-O groups, resulting in an increase in the Li-ion storage capacity. The B-SWCNTs exhibit a high reversible gravimetric capacity of 344 mA h g at 0.1 A g without noticeable capacity fading after 1000 cycles. Furthermore, it delivers a high gravimetric energy density of 797 W h kg at a low gravimetric power density of 300 W kg and retains its high gravimetric energy density of ∼100 W h kg at a high gravimetric power of 10 W kg. These results suggest that the highly exfoliated, oxygen-functionalized single-walled carbon nanotubes can be applied to LIBs designed for high-rate operations and long cycling.
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http://dx.doi.org/10.1021/acsami.9b17311DOI Listing
January 2020

A design principle of root length distribution of plants.

J R Soc Interface 2019 12 4;16(161):20190556. Epub 2019 Dec 4.

Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.

Shaping a plant root into an ideal structure for water capture is increasingly important for sustainable agriculture in the era of global climate change. Although the current genetic engineering of crops favours deep-reaching roots, here we show that nature has apparently adopted a different strategy of shaping roots. We construct a mathematical model for optimal root length distribution by considering that plants seek maximal water uptake at the metabolic expenses of root growth. Our theory finds a logarithmic decrease of root length density with depth to be most beneficial for efficient water uptake, which is supported by biological data as well as our experiments using root-mimicking network systems. Our study provides a tool to gauge the relative performance of root networks in transgenic plants engineered to endure a water deficit. Moreover, we lay a fundamental framework for mechanical understanding and design of water-absorptive growing networks, such as medical and industrial fluid transport systems and soft robots, which grow in porous media including soils and biotissues.
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http://dx.doi.org/10.1098/rsif.2019.0556DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936045PMC
December 2019

BRAF and NRAS mutations and antitumor immunity in Korean malignant melanomas and their prognostic relevance: Gene set enrichment analysis and CIBERSORT analysis.

Pathol Res Pract 2019 Dec 27;215(12):152671. Epub 2019 Sep 27.

Department of Hematological Oncology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, 22, Gwanpyeong-ro 170beon-gil, Dongan-gu, Anyang-si, Gyeonggi-do, 14068, Republic of Korea.

Cutaneous malignant melanomas (CMMs) are rare but are the cause of the highest skin cancer-related mortality in Korea. Very few studies have investigated the associations between KRAS, NRAS, BRAF, and PIK3CA mutations and TICs, as well as their prognostic impact on Korean CMMs. Peptide nucleic acid-mediated polymerase chain reaction clamping and Mutyper and immunohistochemistry were used to detect these mutations in 47 paraffinized CMMs. BRAF and NRAS mutations were detected in 21.3% and 12.8% of CMMs, respectively. No KRAS or PIK3CA mutations were identified. NRAS mutations correlated with low FOXP3 (regulatory T lymphocyte marker) and indoleamine 2,3-dioxygenase (IDO) (activated dendritic cell marker) TICs in CMMs, which is consistent with the negative correlation of regulatory T cells with NRAS mutations in TCGA data, while BRAF mutations were not associated with any TICs. In gene set enrichment analysis, BRAF and NRAS mutations were enriched in decreased CD8 (suppressor/cytotoxic T lymphocyte marker) T cell-linked and increased CD4 (helper/inducer T lymphocyte marker) T cell-linked gene signatures, respectively, confirming the trend in our cohort of associations only with NRAS. BRAF or NRAS mutations alone did not affect any prognosis. In the subgroup analyses, BRAF mutations, as well as high CD4, CD8, FOXP3, and IDO TICs, caused worse overall survival in NRAS-mutated melanoma. No correlation of CD163 (monocyte-macrophage-specific marker) was detected. We found that approximately one-third of our cohort had BRAF and NRAS mutations, none had KRAS or PIK3CA mutations, and most displayed decreased anti-tumor immunity. These findings may warrant further study on combined immunotherapeutic and molecular targeted therapy in Korean CMMs. Subgroup analyses according to TICs and BRAF/NRAS mutations may help to identify high-risk patients with worse prognoses.
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http://dx.doi.org/10.1016/j.prp.2019.152671DOI Listing
December 2019

A Novel Pathogenic CALR Exon 9 Mutation in a Patient with Essential Thrombocythemia.

Lab Med 2020 May;51(3):306-309

Department of Laboratory Medicine, Hallym University Sacred Heart Hospital, Anyang, South Korea.

The clinical phenotypes and prognoses of CALR-mutant myeloproliferative neoplasms depend on the mutation type. The 2 most common mutations, type 1 (52-bp deletion) and type 2 (5-bp insertion), account for 85% of CALR-mutated neoplasms. The former confers a myelofibrotic phenotype, and the latter is associated with a low risk of thrombosis and an indolent clinical course. Individual case reports for patients with novel pathogenic CALR mutations are rare. Herein, we present the first case in the literature, to our knowledge, of a 63-year old ethnic Korean man with essential thrombocythemia who was diagnosed with a novel +1-bp frameshift mutation in CALR, which was predicted to exhibit a type 2-like phenotype.
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http://dx.doi.org/10.1093/labmed/lmz064DOI Listing
May 2020

Which strategy is better for resectable synchronous liver metastasis from colorectal cancer, simultaneous surgery, or staged surgery? Multicenter retrospective analysis.

Ann Surg Treat Res 2019 Oct 1;97(4):184-193. Epub 2019 Oct 1.

Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.

Purpose: The optimal treatment for synchronous liver metastasis (LM) from colorectal cancer (CRC) depends on various factors. The present study was intended to investigate the oncologic outcome according to the time of resection of metastatic lesions.

Methods: Data from patients who underwent treatment with curative intent for primary CRC and synchronous LM between 2004 and 2009 from 9 university hospitals in Korea were collected retrospectively. One hundred forty-three patients underwent simultaneous resection for primary CRC and synchronous LM (simultaneous surgery group), and 65 patients were treated by 2-stage operation (staged surgery group).

Results: The mean follow-up length was 41.2 ± 24.6 months. In the extent of resection for hepatic metastasis, major hepatectomy was more frequently performed in staged surgery group (33.8% 8.4%, P < 0.001). The rate of severe complications of Clavien-Dindo classification grade III or more was not significantly different between the 2 groups. The 3-year overall survival (OS) rate was 85.0% in staged surgery group and 69.4% in simultaneous surgery group (P = 0.013), and the 3-year recurrence-free survival (RFS) rate was 46.4% in staged surgery group and 30.2% in simultaneous surgery group (P = 0.143). In subgroup analysis based on the location of primary CRC, the benefit of staged surgery for OS and RFS was clearly shown in rectal cancer (P = 0.021 and P = 0.015).

Conclusion: Based on our results, staged surgery with or without neoadjuvant chemotherapy should be considered for resectable synchronous LM from CRC, especially in rectal cancer, as a safe and fairly promising option.
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http://dx.doi.org/10.4174/astr.2019.97.4.184DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6779956PMC
October 2019
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