Publications by authors named "Hyunjung Kim"

267 Publications

A CFD study of the transport and fate of airborne droplets in a ventilated office: The role of droplet-droplet interactions.

Front Environ Sci Eng 2022 20;16(3):31. Epub 2021 Jun 20.

Department of Environment and Energy, Jeonbuk National University, Jeonju Jeonbuk, 54896 Republic of Korea.

Previous studies reported that specially designed ventilation systems provide good air quality and safe environment by removing airborne droplets that contain viruses expelled by infected people. These water droplets can be stable in the environment and remain suspended in air for prolonged periods. Encounters between droplets may occur and droplet interactions should be considered. However, the previous studies focused on other physical phenomena (air flow, drag force, evaporation) for droplet transport and neglected droplet interactions. In this work, we used computational fluid dynamics (CFD) to simulate the transport and fate of airborne droplets expelled by an asymptomatic person and considered droplet interactions. Droplet drag with turbulence for prediction of transport and fate of droplets indicated that the turbulence increased the transport of 1 µm droplets, whereas it decreased the transport of 50 µm droplets. In contrast to only considering drag and turbulence, consideration of droplet interactions tended to increase both the transport and fate. Although the length scale of the office is much larger than the droplet sizes, the droplet interactions, which occurred at the initial stages of release when droplet separation distances were shorter, had a significant effect in droplet fate by considerably manipulating the final locations on surfaces where droplets adhered. Therefore, it is proposed that when an exact prediction of transport and fate is required, especially for high droplet concentrations, the effects of droplet interactions should not be ignored.

Electronic Supplementary Material: Supplementary material is available in the online version of this article at 10.1007/s11783-021-1465-8 and is accessible for authorized users.
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http://dx.doi.org/10.1007/s11783-021-1465-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8239320PMC
June 2021

Application of Thromboelastographic Markers to Predict the Survival in Acute Trauma Patients.

Clin Lab 2021 Jun;67(6)

Background: The aim of the study is to investigate the coagulation status in trauma patients using thromboelastography and their association with survival and blood transfusion.

Methods: We included 452 trauma patients who visited the trauma center of Uijeongbu St. Mary's Hospital. The thromboelastography (TEG) clotting variables and routine coagulation tests were evaluated. Also, we investigated the transfusion requirement and mortality during hospitalization period.

Results: The mean age was 52.3 years and the mortality rate was 39/452 (8.6%). Lower GCS, longer TEG K-time, and lower TEG MA were independent factors associated with mortality. The lower MA group demonstrated the highest probability of survival (odds ratio 0.207), followed by prolonged R-time (odds ratio 0.220). The patient numbers in fibrinolysis shutdown (SD), physiologic fibrinolysis, and hyperfibrinolysis groups were 219 (52.3%), 131 (31.4%), and 68 (16.3%), respectively. The mortality rates of fibrinolysis SD group (11.9%) and hyperfibrinolysis (8.8%) were higher than the physiologic fibrinolysis groups (3.8%). The cutoff obtained from ROC analysis was found to be suitable for predicting survival. The transfusion requirements were significantly higher in the fibrinolysis SD group than in the other two groups.

Conclusions: TEG based markers were shown to be more useful to make a diagnosis of coagulopathies including dysfibrinolysis and predict the survival than routine coagulation tests. Dysfunctional fibrinolysis showed higher mortality than physiologic group. If multiple integrations of each TEG markers are used, it would be helpful for prompt diagnosis and management of coagulopathies and to decrease preventable deaths in trauma.
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http://dx.doi.org/10.7754/Clin.Lab.2020.200834DOI Listing
June 2021

An improved extraction method for acrylamide determination in fruit and vegetable chips through enzyme addition.

Food Chem 2021 Oct 11;360:129740. Epub 2021 May 11.

Department of Food and Drug, Seoul Metropolitan Government Research Institute of Public Health and Environment, 30, Janggunmaeul 3-gil, Gwacheon, Republic of Korea.

An enzyme-addition method to pretreat fried fruit and vegetable chips for acrylamide analysis is reported, followed by determination of the acrylamide contents in 36 marketed fruit and vegetable chip products using LC-MS/MS. To improve the extraction process, the FDA method was modified. Specifically, digestive enzymes were added, overcoming the clogging of filters (or SPE cartridges) after extraction of vegetable chips using water. Diastase was added to extract high-starch products, including potato chips. Recoveries of 90.3-105.5% acrylamide were obtained at the spiking levels of 25-500 μg/kg. LOD and LOQ were similar between the method with (4.5 and 13.7 μg/kg) and without diastase addition (4.4 and 13.2 μg/kg). Okra chip with high mucin content was extracted after adding pepsin. This method provided a recovery of 99.8-102.2%, LOD of 6.0 μg/kg, and LOQ of 18.1 μg/kg. Both methods could be used for analyzing acrylamide, with critical method parameters satisfying European Union regulations.
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http://dx.doi.org/10.1016/j.foodchem.2021.129740DOI Listing
October 2021

Efficient degradation of tetracycline by [email protected] titanium dioxide nanofluid via enhanced catalysis and photothermal conversion.

Sci Total Environ 2021 Sep 5;787:147536. Epub 2021 May 5.

College of Environmental Science and Engineering, Donghua University, Shanghai 201620, PR China. Electronic address:

The applications of photocatalytic pollutant degradation have remained limited due to the low efficiency of solar energy utilization. In this study, a photothermal catalyst consisting of reduced graphene oxide @ black TiO ([email protected]) nanofluid with effective full-spectrum (from ultraviolet to infrared light) absorption was synthesized by a typical two-step method of high temperature calcination and hydrothermal method. Moreover, the photothermal catalytic performance of the [email protected] nanofluid on tetracycline was verified. Compared with individual processes (i.e, photocatalysis and thermocatalysis), the photothermal catalytic process significantly enhanced tetracycline degradation under simulated global standard spectrum sunlight (AM 1.5G, 1000 W m). The maximum photothermal conversion efficiency reached 91.8%, which resulted in 94.7% tetracycline degradation (40 mg L) after 120 min of treatment with 200 mg L [email protected] nanofluid. Holes, OH, and O were found to be the main active species during the photothermal catalytic process. Moreover, heat was spontaneously converted from light energy without the use of any external energy source. The elevated system temperature facilitated the tetracycline degradation based on the Arrhenius behavior. These findings provide insights into the improvement of photocatalytic efficiency in organic contaminant degradation via solar energy-efficient photothermal conversion materials.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147536DOI Listing
September 2021

Sustainable treatment of bimetallic (Ag-Pd/α-AlO) catalyst waste from naptha cracking process: An innovative waste-to-value recycling of precious metals.

J Environ Manage 2021 Aug 7;291:112748. Epub 2021 May 7.

Department of Environment and Energy, Jeonbuk National University, Jeonju, Jeonbuk, 54896, Republic of Korea; Department of Mineral Resources and Energy Engineering, Jeonbuk National University, Jeonju, Jeonbuk, 54896, Republic of Korea. Electronic address:

Bimetallic (Ag-Pd/α-AlO) catalysts are essentially applied to naptha-cracking process with a controlled CO emission. After losing the catalytic properties in long run, the landfilling disposal of spent catalysts poses severe stress to the environment and deprivation of precious metals. Therefore, an innovative solvo-chemical recycling approach that involving the solid-liquid and liquid-liquid mass transfer phenomena was studied. The parametric variations for dissolving precious metals yielded >98% efficiency at a lixiviant concentration, 2.0 mol L HCl; pulp density, 20% (wt./vol.); agitation speed, 300 rpm, temperature, 90 °C, and duration, 60 min. The activation energy of silver (6.9 kJ mol) and palladium (11.9 kJ mol) leaching indicated that the process was governed by a diffusion-controlled mechanism. Subsequently, silver and palladium were separated using 0.15 mol L LIX 84-I at different acid concentration that yielding the maximum separation factor (β = 12,501) at 2.0 mol L HCl. Stripping of separately (Ag/Pd)-loaded organic solutions with different solutions of HNO, (NH)SO, and CHNS showed higher affinity for thiourea, yielding 56%, 38%, and 87% efficiency, respectively. Thus the counter-current extraction at an organic-to-aqueous (O:A) ratio of 1:2.5 and stripping with 0.5 mol L CHNS at an O:A ratio of 2:1 yielded a five-fold enrich solutions of precious metals (75.2 mg L Ag and 188.5 mg L Pd) with a purity of >99.9%. The process essentially aims to Goal 12 under the United Nations' Sustainable Development Goals for sustainable recycling of industrial wastes consequently conserving the natural mineral reserves.
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http://dx.doi.org/10.1016/j.jenvman.2021.112748DOI Listing
August 2021

O-enriched microbial activity with pH-sensitive solvo-chemical and electro-chlorination strategy to reclaim critical metals from the hazardous waste printed circuit boards.

J Hazard Mater 2021 08 30;416:125769. Epub 2021 Mar 30.

Department of Mineral Resources and Energy Engineering, Jeonbuk National University, Jeonju, Jeonbuk 54896, Republic of Korea; Department of Environment and Energy, Jeonbuk National University, Jeonju, Jeonbuk 54896, Republic of Korea. Electronic address:

An innovative process integration for the sustainable recovery of critical metals from waste printed circuit boards (WPCBs) is demonstrated. In the acid pre-treatment of WPCBs, > 95% of highly toxic metals lead and tin could dissolve after 240 min of contact in 4.0 mol L HNO. Thereafter, the microbial activity of Sulfobacillus thermosulfidooxidans (strain RDB) under intense aeration is found favorable for base metals' liberation. ~92% copper, 89% nickel, and 93% zinc get extracted at the optimal condition of O-mixed-aeration, 30%; pulp density, 10 g L; aeration rate, 0.5 L min; sulfur dosage, 2%; temperature, 45 °C; and duration, 21 days. Quantitative separation of base metals is achieved using ketoxime as a function of equilibrium pH that yielding pH order: Cu (1.45) < Ni (5.7) < Zn (8.1). The residual gold from WPCBs is uniquely leached (~99% efficiency) in brine solution (2.0 mol L NaCl) under the electro-chlorination rate, 0.62 mmol min; dissolution pH, 1.0; pulp density, 20 g L; temperature, 30 °C; and time, 60 min. Subsequently, gold from brine solution is solvated with tri-butyl-phosphate at pH, ≤ 0.5, forming [2(RP=O)·HAuCl·HO]¯ complex in the organic phase. Finally, > 99% of high-purity gold is stripped from loaded organic while contacting ammoniacal thiosulfate solution in two-stages of counter-current flow.
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http://dx.doi.org/10.1016/j.jhazmat.2021.125769DOI Listing
August 2021

Compliance with Infection Prevention and Control Practice among Prospective Graduates of Nursing School in South Korea.

Int J Environ Res Public Health 2021 03 1;18(5). Epub 2021 Mar 1.

College of Nursing, Kangwon National University, Gangwon-do 24341, Korea.

The purpose of this study was to examine compliance with infection prevention and control practice and factors affecting compliance in nursing students who are about to graduate. A cross-sectional survey design was used. A total of 178 students from two nursing colleges in South Korea responded to self-reported questionnaires. Descriptive statistics, independent t-test, Pearson correlation, and multiple regression analysis were conducted. Mean score for compliance was 4.09 ± 0.43 out of 5. The highest score was on compliance with prevention of cross-infection (4.42 ± 0.54) and the lowest was on use of protective devices (3.86 ± 0.78). Non-occupational exposure scores on compliance subcategories were significantly higher than those for occupational exposure. Students' perception of safe environment for infection control and a positive attitude toward infection control predicted compliance significantly (β = 0.28, < 0.001; β = 0.18, = 0.014, respectively). The findings clarify that the level of infection control compliance among Korean nursing students is moderate. In order to increase the level of compliance, a climate that emphasizes a safe environment for healthcare-associated infections should be strengthened. In addition, nursing education should endeavor to develop a positive attitude toward infection prevention.
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http://dx.doi.org/10.3390/ijerph18052373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7967753PMC
March 2021

Corrigendum: A Coordinated Suite of Wild-Introgression Lines in and Elite Backgrounds.

Front Plant Sci 2020 2;11:640122. Epub 2021 Mar 2.

Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States.

[This corrects the article DOI: 10.3389/fpls.2020.564824.].
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http://dx.doi.org/10.3389/fpls.2020.640122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7961302PMC
March 2021

Psychometric comparisons of measures of eHealth literacy using a sample of Korean older adults.

Int J Older People Nurs 2021 May 1;16(3):e12369. Epub 2021 Feb 1.

College of Nursing & The Research Institute of Nursing Science, Seoul National University, Seoul, South Korea.

Aims: This study aimed to compare the psychometric properties of two measures of eHealth literacy, namely, the Korean versions of the Digital Health Literacy Instrument (K-DHLI) and eHealth Literacy Scale (K-eHEALS), among older adults in South Korea.

Background: Given the usefulness of eHealth information, measures of eHealth literacy have been developed. It is necessary to examine the validity of such tools among older adults who are likely to experience difficulties in using eHealth resources.

Methods: A validation study was conducted using the secondary data of 180 older adults in South Korea. Two weeks after they had responded to the K-DHLI and K-eHEALS, 89 of them completed the assessments a second time so that the assessments' test-retest reliability could be examined. Using the collected data, their reliability (i.e. internal consistency, test-retest reliability) and validity (i.e. construct validity and criterion validity) were examined.

Results: Both tools demonstrated satisfactory internal consistency (α ≥ 0.90, item-total correlation coefficients = .39-.76) as well as good test-retest reliability with intraclass correlation coefficients .77 and .84, respectively. The 21 items of the K-DHLI loaded onto five factors, which accounted for 71% of the variance. The 10 items of the K-eHEALS loaded onto a single factor, which explained 58% of the total variance. The scores of both tools were strongly correlated (r = .63) and positively related to attitudes towards internet health information and subjective health status (r = .23-.50).

Conclusions: The findings suggest that the K-DHLI and K-eHEALS are reliable and valid tools that can be used to assess the utilisation of eHealth resources by older adults.

Implications For Practice: The findings can help healthcare providers choose a suitable measure of eHealth literacy when working with older adults.
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http://dx.doi.org/10.1111/opn.12369DOI Listing
May 2021

Colloid Interaction Energies for Surfaces with Steric Effects and Incompressible and/or Compressible Roughness.

Langmuir 2021 02 20;37(4):1501-1510. Epub 2021 Jan 20.

Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China.

Colloid aggregation and retention in the presence of macromolecular coatings (e.g., adsorbed polymers, surfactants, proteins, biological exudates, and humic materials) have previously been correlated with electric double layer interactions or repulsive steric interactions, but the underlying causes are not fully resolved. An interaction energy model that accounts for double layer, van der Waals, Born, and steric interactions as well as nanoscale roughness and charge heterogeneity on both surfaces was extended, and theoretical calculations were conducted to address this gap in knowledge. Macromolecular coatings may produce steric interactions in the model, but non-uniform or incomplete surface coverage may also create compressible nanoscale roughness with a charge that is different from the underlying surface. Model results reveal that compressible nanoscale roughness reduces the energy barrier height and the magnitude of the primary minimum at separation distances exterior to the adsorbed organic layer. The depth of the primary minimum initially alters (e.g., increases or decreases) at separation distances smaller than the adsorbed organic coating because of a decrease in the compressible roughness height and an increase in the roughness fraction. However, further decreases in the separation distance create strong steric repulsion that dominates the interaction energy profile and limits the colloid approach distance. Consequently, adsorbed organic coatings on colloids can create shallow primary minimum interactions adjacent to organic coatings that can explain enhanced stability and limited amounts of aggregation and retention that have commonly been observed. The approach outlined in this manuscript provides an improved tool that can be used to design adsorbed organic coatings for specific colloid applications or interpret experimental observations.
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http://dx.doi.org/10.1021/acs.langmuir.0c03029DOI Listing
February 2021

Mobilisation of hazardous elements from arsenic-rich mine drainage ochres by three Aspergillus species.

J Hazard Mater 2021 05 12;409:124938. Epub 2021 Jan 12.

Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, 84215 Bratislava, Slovakia.

Natural ferric ochres that precipitate in streambeds at abandoned mining sites are natural scavengers of various metals and metalloids. Thus, their chemical and structural modification via microbial activity should be considered in evaluation of the risks emerging from probable spread of contamination at mining sites. Our results highlight the role of various aspergilli strains in this process via production of acidic metabolites that affect mobility and bioavailability of coprecipitated contaminants. The Mössbauer analysis revealed subtle structural changes of iron in ochres, while the elemental analysis of non-dissolved residues of ochres that were exposed to filamentous fungi suggest coinciding bioextraction of arsenic and antimony with extensive iron mobilisation. However, the zinc bioextraction by filamentous fungi is less likely dependent on iron leaching from ferric ochres. The strain specific bioextraction efficiency and subsequent bioaccumulation of mobilised metals resulted in distinct tolerance responses among the studied soil fungal strains. However, regardless the burden of bioextracted metal(loid)s on its activity, the Aspergillus niger strain has shown remarkable capability to decrease pH of its environment and, thus, bioextract significant and environmentally relevant amounts of potentially toxic elements from the natural ochres.
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http://dx.doi.org/10.1016/j.jhazmat.2020.124938DOI Listing
May 2021

Unveiling surface charge on chalcogen atoms toward the high aspect-ratio colloidal growth of two-dimensional transition metal chalcogenides.

Nanoscale 2021 Jan;13(2):1291-1302

Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, 2066 Seoburo, Jangan-gu, Sown, Gyeonggi-do 440-746, Republic of Korea. and Department of Chemistry, Sungkyunkwan University, 2066 Seoburo, Jangan-gu, Sown, Gyeonggi-do 440-746, Republic of Korea and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, 2066 Seoburo, Jangan-gu, Suwon 16419, Republic of Korea.

Controlling surface energies of each facet is essential for the anisotropic growth of two-dimensional transition metal chalcogenides (TMCs). However, it is a challenge due to stronger binding energies of ligand head groups to the edge facets compared to the planar facets. Herein, we demonstrate that the adsorption of ligands on metal positions can induce partial electron localization on the chalcogen sites, and then accelerate metal-chalcogen bond formation for enhanced anisotropic growth of nanosheets. And only in the case of trioctylphosphine oxide (TOPO)-adsorbed nanosheets, surface polarization can be unveiled on the surface of the colloidal nanosheets due to restricted development of nonpolar ligand shells by the steric effects of the ligands. Moreover, density functional theory (DFT) calculation results reveal that the decrease of surface energy on the (100) edge facets as well as the increase on the (001) basal facets by the adsorption of triorganylphosphine oxide also contribute to the preferentially lateral growth. As a result, various 2D TMCs, including MoSe2, WSe2, and SnSe2 synthesized with TOPO, show enhanced anisotropic growth.
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http://dx.doi.org/10.1039/d0nr06448cDOI Listing
January 2021

Circular bioeconomy and environmental benignness through microbial recycling of e-waste: A case study on copper and gold restoration.

Waste Manag 2021 Feb 25;121:175-185. Epub 2020 Dec 25.

Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390002, Gujarat, India.

This study has attempted to ascertain the linkages between circular bio-economy (CirBioeco) and recycling of electronic (e-)waste by applying microbial activities instead of the smelter and chemical technologies. To build the research hypothesis, the advances on biotechnology-driven recycling processes for metals extraction from e-waste has been analyzed briefly. Thereafter, based on the potential of microbial techniques and research hypothesis, the structural model has been tested for a significance level of 99%, which is supported by the corresponding standardization co-efficient values. A prediction model applied to determine the recycling impact on CirBioeco indicates to re-circulate 51,833 tons of copper and 58 tons of gold by 2030 for the production of virgin metals/raw-materials, while recycling rate of the accumulated e-waste remains to be 20%. This restoration volume of copper and gold through the microbial activities corresponds to mitigate 174 million kg CO emissions and 24 million m water consumption if compared with the primary production activities. The study potentially opens a new window for environmentally-friendly biotechnological recycling of e-waste under the umbrella concept of CirBioeco.
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http://dx.doi.org/10.1016/j.wasman.2020.12.013DOI Listing
February 2021

A Coordinated Suite of Wild-Introgression Lines in and Elite Backgrounds.

Front Plant Sci 2020 12;11:564824. Epub 2020 Nov 12.

Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States.

Rice, L., is a cultivated, inbreeding species that serves as the staple food for the largest number of people on earth. It has two strongly diverged varietal groups, and , which result from a combination of natural and human selection. The genetic divergence of these groups reflects the underlying population structure of their wild ancestors, and suggests that a pre-breeding strategy designed to take advantage of existing genetic, geographic and ecological substructure may provide a rational approach to the utilization of crop wild ancestors in plant improvement. Here we describe the coordinated development of six introgression libraries ( = 63 to 81 lines per library) in both (cv. IR64) and (cv. Cybonnet) backgrounds using three bio-geographically diverse wild donors representing the Species Complex from China, Laos and Indonesia. The final libraries were genotyped using an Infinium 7K rice SNP array (C7AIR) and analyzed under greenhouse conditions for several simply inherited (Mendelian) traits. These six interspecific populations can be used as individual Chromosome Segment Substitution Line libraries and, when considered together, serve as a powerful genetic resource for systematic genetic dissection of agronomic, physiological and developmental traits in rice.
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http://dx.doi.org/10.3389/fpls.2020.564824DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7688981PMC
November 2020

Screening of myelodysplastic syndrome using cell population data obtained from an automatic hematology analyzer.

Int J Lab Hematol 2021 04 20;43(2):e54-e57. Epub 2020 Nov 20.

Department of Laboratory Medicine, College of Medicine, Catholic University of Korea, Seoul, Korea.

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http://dx.doi.org/10.1111/ijlh.13361DOI Listing
April 2021

Time-resolved in situ visualization of the structural response of zeolites during catalysis.

Nat Commun 2020 Nov 19;11(1):5901. Epub 2020 Nov 19.

Department of Physics, Sogang University, Seoul, 04107, Korea.

Zeolites are three-dimensional aluminosilicates having unique properties from the size and connectivity of their sub-nanometer pores, the Si/Al ratio of the anionic framework, and the charge-balancing cations. The inhomogeneous distribution of the cations affects their catalytic performances because it influences the intra-crystalline diffusion rates of the reactants and products. However, the structural deformation regarding inhomogeneous active regions during the catalysis is not yet observed by conventional analytical tools. Here we employ in situ X-ray free electron laser-based time-resolved coherent X-ray diffraction imaging to investigate the internal deformations originating from the inhomogeneous Cu ion distributions in Cu-exchanged ZSM-5 zeolite crystals during the deoxygenation of nitrogen oxides with propene. We show that the interactions between the reactants and the active sites lead to an unusual strain distribution, confirmed by density functional theory simulations. These observations provide insights into the role of structural inhomogeneity in zeolites during catalysis and will assist the future design of zeolites for their applications.
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http://dx.doi.org/10.1038/s41467-020-19728-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7677390PMC
November 2020

Decreases Bioavailability of Arsenic(V) via Biotransformation of Manganese Oxide into Biogenic Oxalate Minerals.

J Fungi (Basel) 2020 Nov 9;6(4). Epub 2020 Nov 9.

Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, 84215 Bratislava, Slovakia.

The aim of this work was to evaluate the transformation of manganese oxide (hausmannite) by microscopic filamentous fungus and the effects of the transformation on mobility and bioavailability of arsenic. Our results showed that the strain CBS 140837 greatly affected the stability of hausmannite and induced its transformation into biogenic crystals of manganese oxalates-falottaite and lindbergite. The transformation was enabled by fungal acidolysis of hausmannite and subsequent release of manganese ions into the culture medium. While almost 45% of manganese was bioextracted, the arsenic content in manganese precipitates increased throughout the 25-day static cultivation of fungus. This significantly decreased the bioavailability of arsenic for the fungus. These results highlight the unique strain's ability to act as an active geochemical factor via its ability to acidify its environment and to induce formation of biogenic minerals. This affects not only the manganese speciation, but also bioaccumulation of potentially toxic metals and metalloids associated with manganese oxides, including arsenic.
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http://dx.doi.org/10.3390/jof6040270DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7711977PMC
November 2020

In Situ Strain Evolution on Pt Nanoparticles during Hydrogen Peroxide Decomposition.

Nano Lett 2020 Dec 11;20(12):8541-8548. Epub 2020 Nov 11.

Department of Physics, Sogang University, Seoul 04107, Korea.

Fundamental understanding of structural changes during catalytic reactions is crucial to understanding the underlying mechanisms and optimizing efficiencies. Surface energy and related catalytic mechanisms are widely studied. However, the catalyst lattice deformation induced by catalytic processes is not well understood. Here, we study the strain in an individual platinum (Pt) nanoparticle (NP) using Bragg coherent diffraction imaging under in situ oxidation and reduction reactions. When Pt NPs are exposed to HO, a typical oxidizer and an intermediate during the oxygen reduction reaction process, alternating overall strain distribution near the surface and inside the NP is observed at the (111) Bragg reflection. In contrast, relatively insignificant changes appear in the (200) reflection. Density functional theory calculations are employed to rationalize the anisotropic lattice strain in terms of induced stress by HO adsorption and decomposition on the Pt NP surface. Our study provides deeper insight into the activity-structure relationship in this system.
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http://dx.doi.org/10.1021/acs.nanolett.0c03005DOI Listing
December 2020

Synthesis and Application of -methylphthalimidylazo Disperse Dyes to Cellulose Diacetate for High Wash Fastness.

Materials (Basel) 2020 Nov 2;13(21). Epub 2020 Nov 2.

Department of Organic and Nano System Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Korea.

Cellulose diacetate fibers were prepared from cellulosic biomass with high α-cellulose contents such as purified cotton linters and wood pulps. Cellulose diacetate fibers are sensitive to alkaline solution, which causes hydrolysis of the acetate ester to hydroxyl groups, especially at high temperatures. Thus, the low alkali-resistance of cellulose acetate fibers makes it difficult to achieve high wash fastness by restricting the application of intense after-treatment, such as reduction clearing. A series of -methylphthalimide-based high-washable azo disperse dyes were synthesized and their dyeing and fastness properties on cellulose diacetate fabrics were investigated. From the overall results obtained in this study, -methylphthalimidylazo disperse dyes are expected to be a desirable alternative to high value-added dyes that can be used for high color fastness dyeing of cellulose diacetate with a minimal discharge of wastewater during washing process.
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http://dx.doi.org/10.3390/ma13214924DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7662543PMC
November 2020

High-yield synthesis of a tau PET radioligand and its nonradioactive ligand using an alternative protection and deprotection strategy.

J Labelled Comp Radiopharm 2021 Apr 26;64(4):150-158. Epub 2020 Nov 26.

Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.

Recently developed tau imaging radiopharmaceuticals show specific uptake in tau protein-rich regions in human brains without off-target binding. These radiopharmaceuticals and their nonradioactive reference ligands are generally obtained in low (radio)chemical yields. In the present study, we investigated high-yield synthesis of F-RO948 ([ F]1) and its nonradioactive ligand (1). The ligand 1 was synthesized by a Suzuki-Miyaura coupling reaction between 9-(4-methoxybenzyl)-9H-pyrrolo[2,3-b:4,5-c']dipyridin-2-yl trifluoromethanesulfonate (3) and 2-fluoro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (4), followed by oxidative removal of the para-methoxybenzyl (PMB) group with ceric ammonium nitrate (CAN). This two-step reaction gave 1 in 55.8% yield. The precursor for [ F]1 was synthesized from 3 and 2-nitro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (6). The resulting PMB-protected precursor 8 was obtained in 74.5% yield. [ F]1 was synthesized by radiofluorination of 8 (radiochemical conversion (RCC): 95.7 ± 1.7%), followed by deprotection of the PMB group with CAN. This one-pot, two-step radiochemical synthesis followed by HPLC purification gave [ F]1 in high decay-corrected radiochemical yield (54-60%). The RCC of [ F]fluoride to [ F]1 in our two-step synthesis method was similar to that in a one-step radiofluorination reaction of a tert-butoxycarbonyl (BOC)-protected precursor 10 that proceeds with concomitant thermal deprotection of the BOC group. Taken together, the results of this study suggest that this high-yield synthesis method is useful for the synthesis of F-labeled (NH)heteroarene compounds.
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http://dx.doi.org/10.1002/jlcr.3894DOI Listing
April 2021

Assessment of Strain's Suitability for Arsenate-Contaminated Water Treatment and Adsorbent Recycling via Bioextraction in a Laboratory-Scale Experiment.

Microorganisms 2020 Oct 27;8(11). Epub 2020 Oct 27.

Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 84215 Bratislava, Slovakia.

In this work, the viability of bioaccumulation and bioextraction processes for arsenic removal from contaminated waters, as well as the recycling of arsenate-treated amorphous ferric oxyhydroxide adsorbent (FeOOH) were evaluated using the common soil microscopic filamentous fungus . After treating the contaminated arsenate solution (100 mg As L) with FeOOH, the remaining solution was exposed to the growing fungus during a static 19-day cultivation period to further decrease the arsenic concentration. Our data indicated that although the FeOOH adsorbent is suitable for arsenate removal with up to 84% removal efficiency, the fungus was capable of accumulating only up to 13.2% of the remaining arsenic from the culture media. This shows that the fungus , although highly praised for its application in environmental biotechnology research, was insufficient for decreasing the arsenic contamination to an environmentally acceptable level. However, the bioextraction of arsenic from arsenate-treated FeOOH proved relatively effective for reuse of the adsorbent. Due to its production of acidic metabolites, which decreased pH below 2.7, the fungal strain was capable of removing of up to 98.2% of arsenic from the arsenate-treated FeOOH adsorbent.
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http://dx.doi.org/10.3390/microorganisms8111668DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693371PMC
October 2020

Fungus Processes Exogenous Zinc Nanoparticles into a Biogenic Oxalate Mineral.

J Fungi (Basel) 2020 Oct 8;6(4). Epub 2020 Oct 8.

Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia.

Zinc oxide nanoparticles (ZnO NPs) belong to the most widely used nanoparticles in both commercial products and industrial applications. Hence, they are frequently released into the environment. Soil fungi can affect the mobilization of zinc from ZnO NPs in soils, and thus they can heavily influence the mobility and bioavailability of zinc there. Therefore, ubiquitous soil fungus was selected as a test organism to evaluate the fungal interaction with ZnO NPs. As anticipated, the strain significantly affected the stability of particulate forms of ZnO due to the acidification of its environment. The influence of ZnO NPs on fungus was compared to the aqueous Zn cations and to bulk ZnO as well. Bulk ZnO had the least effect on fungal growth, while the response of to ZnO NPs was comparable with ionic zinc. Our results have shown that soil fungus can efficiently bioaccumulate Zn that was bioextracted from ZnO. Furthermore, it influences Zn bioavailability to plants by ZnO NPs transformation to stable biogenic minerals. Hence, a newly formed biogenic mineral phase of zinc oxalate was identified after the experiment with strain's extracellular metabolites highlighting the fungal significance in zinc biogeochemistry.
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http://dx.doi.org/10.3390/jof6040210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7712133PMC
October 2020

Building on Evidence to Improve eHealth Literacy in Older Adults: A Systematic Review.

Comput Inform Nurs 2021 05;39(5):241-247

Author Affiliations: College of Nursing & Research Institute of Nursing Science, Seoul National University (Dr Chang); and Red Cross College of Nursing, Chung-Ang University (Drs Jang and Lee), Seoul; and Division of Nursing & Research Institute of Nursing Science, Hallym University, Chuncheon (Dr Kim), South Korea.

This review aimed to provide information on ways to improve eHealth literacy in older adults by assessing current studies examining eHealth literacy. To achieve the aim, this review focused on what theories or theoretical frameworks were used in the studies, what factors were related to eHealth literacy, and what outcome variables were used in eHealth literacy interventions for older adults. Five electronic databases were searched to identify eligible studies. The Cochrane Handbook for Systematic Reviews of Interventions was followed to select relevant studies, and narrative synthesis was performed. Among a total of 27 studies, 13 described theories or theoretical frameworks. Credibility in Internet health information, knowledge, and experience were identified as modifiable factors related to eHealth literacy. The most frequently used outcome variable was eHealth literacy efficacy. Nurses who are interested in improving eHealth literacy in older adults should consider appropriate theoretical frameworks and multiple factors influencing eHealth literacy.
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http://dx.doi.org/10.1097/CIN.0000000000000674DOI Listing
May 2021

Disinfection technology and strategies for COVID-19 hospital and bio-medical waste management.

Sci Total Environ 2020 Dec 12;749:141652. Epub 2020 Aug 12.

Mineral Resources and Energy Engineering, Jeonbuk National University, Jeonju, Jeonbuk 54896, Republic of Korea. Electronic address:

The isolation wards, institutional quarantine centers, and home quarantine are generating a huge amount of bio-medical waste (BMW) worldwide since the outbreak of novel coronavirus disease-2019 (COVID-19). The personal protective equipment, testing kits, surgical facemasks, and nitrile gloves are the major contributors to waste volume. Discharge of a new category of BMW (COVID-waste) is of great global concern to public health and environmental sustainability if handled inappropriately. It may cause exponential spreading of this fatal disease as waste acts as a vector for SARS-CoV-2, which survives up to 7 days on COVID-waste (like facemasks). Proper disposal of COVID-waste is therefore immediately requires to lower the threat of pandemic spread and for sustainable management of the environmental hazards. Henceforth, in the present article, disinfection technologies for handling COVID-waste from its separate collection to various physical and chemical treatment steps have been reviewed. Furthermore, policy briefs on the global initiatives for COVID-waste management including the applications of different disinfection techniques have also been discussed with some potential examples effectively applied to reduce both health and environmental risks. This article can be of great significance to the strategy development for preventing/controlling the pandemic of similar episodes in the future.
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http://dx.doi.org/10.1016/j.scitotenv.2020.141652DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7419320PMC
December 2020

LXA-FPR2 signaling regulates radiation-induced pulmonary fibrosis via crosstalk with TGF-β/Smad signaling.

Cell Death Dis 2020 08 8;11(8):653. Epub 2020 Aug 8.

Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, South Korea.

Radiation therapy is an important modality in the treatment of lung cancer, but it can lead to radiation pneumonitis, and eventually radiation fibrosis. To date, only few available drugs can effectively manage radiation-induced pulmonary fibrosis. Lipoxins are endogenous molecules exhibit anti-inflammatory and pro-resolving effects. These molecules play a vital role in reducing excessive tissue injury and chronic inflammation; however, their effects on radiation-induced lung injury (RILI) are unknown. In this study, we investigated the effects of lipoxin A (LXA) on RILI using our specialized small-animal model of RILI following focal-ablative lung irradiation (IR). LXA significantly inhibited immune-cell recruitment and reduced IR-induced expression of pro-inflammatory cytokines and fibrotic proteins in the lung lesion sites. In addition, micro-CT revealed that LXA reduced IR-induced increases in lung consolidation volume. The flexiVent assays showed that LXA4 significantly reversed IR-induced lung function damage. Moreover, LXA4 downregulated the activities of NF-κB and the Smad-binding element promoters. The expression of FPR2, an LXA receptor, increased during the development of IR-induced pulmonary fibrosis, whereas silencing of endogenous LXA using an antagonist (WRW4) or FPR2 siRNA resulted in impaired development of pulmonary fibrosis in response to IR. Collectively, these data suggest that LXA could serve as a potent therapeutic agent for alleviating RILI.
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http://dx.doi.org/10.1038/s41419-020-02846-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7434774PMC
August 2020

An ensemble approach of urine sediment image analysis and NMP22 test for detection of bladder cancer cells.

J Clin Lab Anal 2020 Aug 10;34(8):e23345. Epub 2020 Jul 10.

Department of Laboratory Medicine, Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea.

Background: Bladder cancer is the eighth most common cancer and the second most common urological cancer in Korean males. Current diagnostic tools for bladder cancer include cystoscopy (an upper tract study), urine cytology, and nuclear matrix protein 22 (NMP22) test. In this study, we evaluated the detection rate of atypical/malignant urothelial cells in urinary sediment images when flagged for positive NMP22 test.

Methods: NMP22 was measured by NMP22 BladderChek Test (Abbott Laboratories) and urine chemical and sediment analysis were performed by fully automated cobas 6500 urine analyzer (Roche Diagnostics). Specimens that met the manual microscopic examination (MME) criteria were then subjected to an on-screen review of images. We subsequently reviewed sediment images and examined under the microscopy for the flagged cases.

Results: Of the 1217 patients, 345 (28.3%) had positive NMP22 results, whereas 872 (71.7%) had negative results. Out of the positive results, 154 (12.7%) were positive and 191 (15.7%) weakly positive for NMP22. Screened review of flagged specimens (ie, positive NMP22 result) with sediment imaging analysis revealed that suspicious urothelial carcinoma cells were detected in only two cases (0.8%). In the NMP22 negative flagged cases, the suspicious neoplastic cells were not found.

Conclusions: Our findings suggest that the NMP22 test should be added to the flagging criteria for MME to improve diagnostic accuracy. The combination of urine sediment imaging analysis and NMP22 test can significantly assist technicians in the review of specimens.
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http://dx.doi.org/10.1002/jcla.23345DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7439416PMC
August 2020

Activation of Astrocytes in the Dorsomedial Striatum Facilitates Transition From Habitual to Goal-Directed Reward-Seeking Behavior.

Biol Psychiatry 2020 11 6;88(10):797-808. Epub 2020 May 6.

Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota; Department of Psychiatry and Psychology, Mayo Clinic College of Medicine, Rochester, Minnesota. Electronic address:

Background: Habitual reward-seeking behavior is a hallmark of addictive behavior. The role of the dorsomedial striatum (DMS) in regulating goal-directed reward-seeking behavior has been long appreciated. However, it remains unclear how the astrocytic activities in the DMS differentially affect the behavioral shift.

Methods: To investigate the astrocytic activity-driven neuronal synaptic events and behavioral consequences, we chemogenetically activated astrocytes in the DMS using GFAP promoter-driven expression of hM3Dq, the excitatory DREADDs (designer receptors exclusively activated by designer drugs). First, we confirmed the chemogenetically induced cellular activity in the DMS astrocytes using calcium imaging. Then, we recorded electrophysiological changes in the synaptic activity of the two types of medium spiny neurons (MSNs): direct and indirect pathway MSNs. To evaluate the behavioral consequences, we trained mice in nose-poking operant chambers that developed either habitual or goal-directed reward-seeking behaviors.

Results: The activation of DMS astrocytes reduced the frequency of spontaneous excitatory postsynaptic currents in the direct pathway MSNs, whereas it increased the amplitude of the spontaneous excitatory postsynaptic currents and decreased the frequency of spontaneous inhibitory postsynaptic currents in the indirect pathway MSNs. Interestingly, astrocyte-induced DMS neuronal activities are regulated by adenosine metabolism, receptor signaling, and transport. Importantly, mice lacking an astrocytic adenosine transporter, ENT1 (equilibrative nucleoside transporter 1; Slc29a1), show no transition from habitual to goal-directed reward-seeking behaviors upon astrocyte activation, while restoring ENT1 expression in the DMS facilitated this transition.

Conclusions: Our findings reveal that DMS astrocyte activation differentially regulates MSNs' activity and facilitates shifting from habitual to goal-directed reward-seeking behavior.
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http://dx.doi.org/10.1016/j.biopsych.2020.04.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7584758PMC
November 2020

Stromal cell-derived factor-1 as a serologic biomarker for the diagnosis of colon ischemia with chronic cardiovascular disease.

Medicine (Baltimore) 2020 Jun;99(23):e20539

Department of Internal Medicine, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.

Colon ischemia (CI) is the most common ischemic disorder of the gastrointestinal tract. Although some markers of CI, such as procalcitonin and alkaline phosphatase, have been reported, few specific serum markers have been identified. We investigated whether serum stromal cell-derived factor-1 (SDF-1) is a specific marker of CI and clarified the relationship between serum SDF-1 level and CI according to a history of combined chronic cardiovascular disease (CVD).We measured SDF-1 level and other serological markers in 84 patients (control, n = 20; CI without chronic CVD, n = 21; chronic CVD without CI, n = 20; CI with chronic CVD, n = 23).Patients with CI were older than those without CI. There were more women in the CI groups than those without CI. At admission, SDF-1 level was significantly higher in patients having CI with chronic CVD (P < .001) than in other groups. SDF-1 level was significantly higher at admission than at discharge in patients having CI with chronic CVD (P < .001) but not in patients having CI without chronic CVD. SDF-1 level did not differ according to symptoms, involved sites, or duration of hospitalization. At a cutoff value of 0.5 pg/mL for the SDF-1 level in patients having CI with chronic CVD, the sensitivity and specificity for SDF-1 were 91.3% and 95%, respectively. The area-under-the-curve (AUC) value was 0.95. In the logistic regression analysis, an elevation of the SDF-1 level to >0.5 pg/mL was a significant indicator of CI with chronic CVD [odds ratio (OR), 114.914; 95% confidence interval, 10.51 to >999.999; P < .001].SDF-1 could be a useful early biomarker for the diagnosis of CI in patients with chronic CVD.
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http://dx.doi.org/10.1097/MD.0000000000020539DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7306348PMC
June 2020

Impact of C28 Oligosaccharide on Adjuvant Activity of QS-7 Analogues.

J Org Chem 2020 12 28;85(24):15837-15848. Epub 2020 May 28.

We have synthesized a number of Molina (QS) saponin analogues with a different C28 sugar unit, which features either 3,4-diacetyl groups or a 3,4-cyclic carbonate group at the reducing end fucoside to mimic the naturally occurring saponin adjuvant QS-7. Immunological evaluations of these analogues in BALB/c mice indicate that truncating the C28 oligosaccharide of the natural product to the tetrasaccharide (as in (β)) could retain the adjuvant's activity in enhancing IgG1 and IgG2a productions, albeit the activity is lower than that of QS-21. Further truncation or changing stereochemistry of glycosidic linkage between the tetrasaccharide and the triterpenoid quillaic acid (QA) core or within the tetrasaccharide eliminated the saponins' adjuvant activity in terms of IgG production. On the other hand, increasing resemblance to QS-7 increased adjuvant activity and led to saponin 's similar IgG1 and IgG2a activities to QS-21's, indicating that the unique adjuvant activities of QS saponins are determined by their specific structures.
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http://dx.doi.org/10.1021/acs.joc.0c00359DOI Listing
December 2020

Molecular Stacking Effect on Small-Molecular Organic Light-Emitting Diodes Prepared with Solution Process.

ACS Appl Mater Interfaces 2020 May 7;12(20):23244-23251. Epub 2020 May 7.

Department of Information Display, Kyung Hee University, Seoul 02447, Republic of Korea.

The light-emitting layer (EML) is generally prepared by mixing the host and dopant to realize an organic light-emitting diode (OLED). However, phase separation is often observed during the fabrication process to prepare OLEDs, depending on the structure of the host materials. In particular, phase separation because of π-π stacking is frequently observed during thermal annealing for the solution process. The annealing process is required for solvent removal and complete relaxation of the molecule. Hence, the materials with a high glass transition temperature () are ideal because phase separation occurs because of π-π stacking during the annealing process, if is too low. To understand this phenomenon, we compared two host materials with similar molecular weights but different three-dimensional connectivity, which causes different rotational freedom. Then, we investigated the effect on the device properties, depending on the annealing conditions. In both materials, when the annealing temperature rises above 120 °C, the dopant completely escaped from the EML. However, the material that does not disturb the molecular stacking order by annealing because of its limited free rotation through the internal bond shows much better device characteristics even after annealing at a higher temperature than . The results show that interdiffusion at the interface and unstable internal density distribution with annealing temperature are responsible for the device degradation behavior.
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http://dx.doi.org/10.1021/acsami.0c06597DOI Listing
May 2020
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