Publications by authors named "Jae-Hong Kim"

451 Publications

Occurrence of unknown reactive species in UV/HO system leading to false interpretation of hydroxyl radical probe reactions.

Water Res 2021 Jun 10;201:117338. Epub 2021 Jun 10.

Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States. Electronic address:

The UV/HO process is a benchmark advanced oxidation process (AOP) that in situ generates highly reactive and nonselective hydroxyl radical (OH) to oxidatively destroy a wide range of organic compounds. Accurately quantifying the concentration of short-lived OH is essential to predict process performance, optimize the operation parameters, and compare with other process options. The OH concentration is typically measured using organic probe molecules that react with OH but not with other oxidants. In the extremely well-characterized UV/HO system in which OH is proven to be the dominant oxidant, using photolysis-resistant probes such as benzoic acid and its derivatives is a widely agreed and practiced norm. We herein report that certain OH probe compounds can be degraded in UV/HO system by unknown reactive species that has not been reported in the past. Several common organic probes, particularly p-substituted benzoic acid compounds (i.e., p-hydroxybenzoic acid, p-chlorobenzoic acid, and p-phthalic acid), were found to be vulnerable to attack by the unknown reactive species, leading to false quantification of OH concentration under high radical scavenging conditions. Lines of evidence obtained from a series of OH scavenging experiments performed under various conditions (i.e., different concentrations of HO, OH probe compounds, and dissolved oxygen) point toward excited state HO. The results from this study suggest the importance of using appropriate OH probe compounds in mechanistic studies and needs for considering the unidentified role of excited state of HO on the UV/HO process and related AOPs.
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http://dx.doi.org/10.1016/j.watres.2021.117338DOI Listing
June 2021

Membrane-Confined Iron Oxychloride Nanocatalysts for Highly Efficient Heterogeneous Fenton Water Treatment.

Environ Sci Technol 2021 07 21;55(13):9266-9275. Epub 2021 Jun 21.

Department of Chemical and Environmental Engineering, Yale University, 17 Hillhouse Avenue, New Haven, Connecticut 06511, United States.

Heterogeneous advanced oxidation processes (AOPs) allow for the destruction of aqueous organic pollutants via oxidation by hydroxyl radicals (OH). However, practical treatment scenarios suffer from the low availability of short-lived OH in aqueous bulk, due to both mass transfer limitations and quenching by water constituents, such as natural organic matter (NOM). Herein, we overcome these challenges by loading iron oxychloride catalysts within the pores of a ceramic ultrafiltration membrane, resulting in an internal heterogeneous Fenton reaction that can degrade organics in complex water matrices with pH up to 6.2. With OH confined inside the nanopores (∼ 20 nm), this membrane reactor completely removed various organic pollutants with water fluxes of up to 100 L m h (equivalent to a retention time of 10 s). This membrane, with a pore size that excludes NOM (>300 kDa), selectively exposed smaller organics to OH within the pores under confinement and showed excellent resiliency to representative water matrices (simulated surface water and sand filtration effluent samples). Moreover, the membrane exhibited sustained AOPs (>24 h) and could be regenerated for multiple cycles. Our results suggest the feasibility of exploiting ultrafiltration membrane-based AOP platforms for organic pollutant degradation in complex water scenarios.
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http://dx.doi.org/10.1021/acs.est.1c01391DOI Listing
July 2021

Leukotriene B Receptors Are Necessary for the Stimulation of NLRP3 Inflammasome and IL-1β Synthesis in Neutrophil-Dominant Asthmatic Airway Inflammation.

Biomedicines 2021 May 11;9(5). Epub 2021 May 11.

Division of Life Sciences, College of Life Sciences, Korea University, Seoul 02841, Korea.

The stimulation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome and IL-1β synthesis are associated with chronic respiratory diseases such as neutrophil-dominant severe asthma. Leukotriene B (LTB) is a principal chemoattractant molecule for neutrophil recruitment, and its receptors BLT1 and BLT2 have been suggested to contribute to neutrophil-dominant asthmatic airway inflammation. However, the relationship between BLT1/2 and NLRP3 in neutrophil-dominant asthmatic airway inflammation has not been previously studied. In the present study, we investigated whether BLT1/2 play any roles in stimulating the NLRP3 inflammasome and IL-1βsynthesis. The blockade of BLT1 or BLT2 clearly suppressed the stimulation of the NLRP3 inflammasome and IL-1β synthesis in house dust mite (HDM)/lipopolysaccharide (LPS)-induced neutrophilic airway inflammation. The enzymes 5-lipoxygenase and 12-lipoxygenase, which catalyze the synthesis of BLT1/2 ligands [LTB, 12()-hydroxyeicosatetraenoic acid (12()-HETE), and 12-hydroxyheptadecatreinoic acid (12-HHT)], were also critically associated with the stimulation of NLRP3 and IL-1β synthesis. Together, our results suggest that the 5-/12-LOX-BLT1/2-linked cascade are necessary for the simulation of the NLRP3 inflammasome and IL-1β synthesis, thus contributing to HDM/LPS-induced neutrophil-dominant airway inflammation.
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http://dx.doi.org/10.3390/biomedicines9050535DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8151312PMC
May 2021

Identification of Molecules from Coffee Silverskin That Suppresses Myostatin Activity and Improves Muscle Mass and Strength in Mice.

Molecules 2021 May 3;26(9). Epub 2021 May 3.

Department of Human Nutrition, Food and Animal Sciences, University of Hawaii, 1955 East-West Rd., Honolulu, HI 96822, USA.

Coffee has been shown to attenuate sarcopenia, the age-associated muscle atrophy. Myostatin (MSTN), a member of the TGF-β growth/differentiation factor superfamily, is a potent negative regulator of skeletal muscle mass, and MSTN-inhibition increases muscle mass or prevents muscle atrophy. This study, thus, investigated the presence of MSTN-inhibitory capacity in coffee extracts. The ethanol-extract of coffee silverskin (CSE) but not other extracts demonstrated anti-MSTN activity in a pGL3-(CAGA)-luciferase reporter gene assay. CSE also blocked Smad3 phosphorylation induced by MSTN but not by GDF11 or Activin A in Western blot analysis, demonstrating its capacity to block the binding of MSTN to its receptor. Oral administration of CSE significantly increased forelimb muscle mass and grip strength in mice. Using solvent partitioning, solid-phase chromatography, and reverse-phase HPLC, two peaks having MSTN-inhibitory capacity were purified from CSE. The two peaks were identified as -arachinoyl-5-hydroxytryptamide (C-5HT) and -behenoyl-5-hydroxytryptamide (C-5HT) using mass spectrometry and NMR analysis. In summary, the results show that CSE has the MSTN-inhibitory capacity, and C-5HT and C-5HT are active components of CSE-suppressing MSTN activity, suggesting the potential of CSE, C-5HT, and C-5HT being developed as agents to combat muscle atrophy and metabolic syndrome.
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http://dx.doi.org/10.3390/molecules26092676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8124993PMC
May 2021

Factors contributing to cognitive improvement effects of acupuncture in patients with mild cognitive impairment: a pilot randomized controlled trial.

Trials 2021 May 12;22(1):341. Epub 2021 May 12.

Department of Nursing, Christian College of Nursing, Gwangju City, 61662, Republic of Korea.

Background: Mild cognitive impairment (MCI) is generally regarded as the borderline between cognitive changes of aging and very early Alzheimer's disease (AD). It is important to develop easily available interventions to delay the progression of MCI to AD. We investigated factors contributing to the cognitive improvement effects of acupuncture to obtain data for developing optimized acupuncture treatments for MCI.

Methods: This outcome assessor-blinded, randomized controlled trial included a full analysis for comparing the efficacy of different acupuncture methods. Thirty-two participants with MCI (i.e., fulfilling the Peterson diagnostic criteria for MCI, K-MMSE scores of 20-23, and MoCA-K scale scores of 0-22) were randomly assigned to basic acupuncture (BA; GV20, EX-HN1, GB20, and GV24 for 30 min), acupoint specificity (AS; adding KI3 to BA), needle duration (ND; BA for 20 min), or electroacupuncture (EA; electrical stimulation to BA) groups (n=8/group) via 1:1:1:1 allocation and administered acupuncture once daily, three times a week for 8 weeks. The measured outcomes included scores on the Korean version of the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-K-cog), Korean version of the Montreal Cognitive Assessment scale (MoCA-K), Center for Epidemiological Studies-Depression Scale, Korean Activities of Daily Living scale, Korean Instrumental Activities of Daily Living scale, and European Quality of Life Five Dimension Five Level Scale. Outcome measurements were recorded at baseline (week 0), intervention endpoint (week 8), and 12 weeks after intervention completion (week 20).

Results: Twenty-five patients with MCI completed the trial (BA group, 8; AS group, 6; ND group, 5; EA group, 6). MoCA-K scores were significantly increased in the BA group compared with the ND (p=0.008, week 8-week 0) and EA groups (p=0.003, week 8-week 0; p=0.043, week 20-week 0). ADAS-K-cog scores were significantly decreased in the BA group compared with the ND group (p=0.019, week 20-week 0).

Conclusions: The BA group showed significant improvement in cognitive function compared to the ND and EA groups. Electrical stimulation and needle duration may contribute to the cognitive improvement effects of acupuncture in patients with MCI.

Trial Registration: Clinical Research Information Service; URL:cris.nih.go.kr .; unique identifier: KCT0003430 (registration date: January 16, 2019).
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http://dx.doi.org/10.1186/s13063-021-05296-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8117619PMC
May 2021

Design of Center Pillar with Composite Reinforcements Using Hybrid Molding Method.

Materials (Basel) 2021 Apr 20;14(8). Epub 2021 Apr 20.

Department of Nanomechatronics Engineering, Pusan National University, Pusan 46241, Korea.

Recently, with the increase in awareness about a clean environment worldwide, fuel efficiency standards are being strengthened in accordance with exhaust gas regulations. In the automotive industry, various studies are ongoing on vehicle body weight reduction to improve fuel efficiency. This study aims to reduce vehicle weight by replacing the existing steel reinforcements in an automobile center pillar with a composite reinforcement. Composite materials are suitable for weight reduction because of their higher specific strength and stiffness compared to existing steel materials; however, one of the disadvantages is their high material cost. Therefore, a hybrid molding method that simultaneously performs compression and injection was proposed to reduce both process time and production cost. To replace existing steel reinforcements with composite materials, various reinforcement shapes were designed using a carbon fiber-reinforced plastic patch and glass fiber-reinforced plastic ribs. Structural analyses confirmed that, using these composite reinforcements, the same or a higher specific stiffness was achieved compared to the that of an existing center pillar using steel reinforcements. The composite reinforcements resulted in a 67.37% weight reduction compared to the steel reinforcements. In addition, a hybrid mold was designed and manufactured to implement the hybrid process.
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http://dx.doi.org/10.3390/ma14082047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8073303PMC
April 2021

Identification of Genetic Modifiers of TDP-43: Inflammatory Activation of Astrocytes for Neuroinflammation.

Cells 2021 Mar 18;10(3). Epub 2021 Mar 18.

Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu 41944, Korea.

Transactive response DNA-binding protein 43 (TDP-43) is a ubiquitously expressed DNA/RNA-binding protein linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). TDP-43 has been implicated in numerous aspects of the mRNA life cycle, as well as in cell toxicity and neuroinflammation. In this study, we used the toxicity of the TDP-43 expression in as an assay to identify genetic interactions. Specifically, we transformed human cDNAs of wild-type or disease-associated mutants ( and ) en masse into 4653 homozygous diploid yeast deletion mutants and then used next-generation sequencing readouts of growth to identify yeast toxicity modifiers. Genetic interaction analysis provided a global view of TDP-43 pathways, some of which are known to be involved in cellular metabolic processes. Selected putative loci with the potential of genetic interactions with were assessed for associations with neurotoxicity and inflammatory activation of astrocytes. The pharmacological inhibition of succinate dehydrogenase flavoprotein subunit A (SDHA) and voltage-dependent anion-selective channel 3 (VDAC3) suppressed TDP-43-induced expression of proinflammatory cytokines in astrocytes, indicating the critical roles played by SDHA and VDAC3 in TDP-43 pathways during inflammatory activation of astrocytes and neuroinflammation. Thus, the findings of our genetic interaction screen provide a global landscape of TDP-43 pathways and may help improve our understanding of the roles of glia and neuroinflammation in ALS and FTD pathogenesis.
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http://dx.doi.org/10.3390/cells10030676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003223PMC
March 2021

Yale School of Public Health Symposium: An overview of the challenges and opportunities associated with per- and polyfluoroalkyl substances (PFAS).

Sci Total Environ 2021 Jul 3;778:146192. Epub 2021 Mar 3.

Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, USA. Electronic address:

On December 13, 2019, the Yale School of Public Health hosted a symposium titled "Per- and Polyfluoroalkyl Substances (PFAS): Challenges and Opportunities" in New Haven, Connecticut. The meeting focused on the current state of the science on these chemicals, highlighted the challenges unique to PFAS, and explored promising opportunities for addressing them. It brought together participants from Yale University, the National Institute of Environmental Health Sciences, the University of Massachusetts Amherst, the University of Connecticut, the Connecticut Agricultural Experiment Station, the Connecticut Departments of Public Health and Energy and Environmental Protection, and the public and private sectors. Presentations during the symposium centered around several primary themes. The first reviewed the current state of the science on the health effects associated with PFAS exposure and noted key areas that warranted future research. As research in this field relies on specialized laboratory analyses, the second theme considered commercially available methods for PFAS analysis as well as several emerging analytical approaches that support health studies and facilitate the investigation of a broader range of PFAS. Since mitigation of PFAS exposure requires prevention and cleanup of contamination, the third theme highlighted new nanotechnology-enabled PFAS remediation technologies and explored the potential of green chemistry to develop safer alternatives to PFAS. The fourth theme covered collaborative efforts to assess the vulnerability of in-state private wells and small public water supplies to PFAS contamination by adjacent landfills, and the fifth focused on strategies that promote successful community engagement. This symposium supported a unique interdisciplinary coalition established during the development of Connecticut's PFAS Action Plan, and discussions occurring throughout the symposium revealed opportunities for collaborations among Connecticut scientists, state and local officials, and community advocates. In doing so, it bolstered the State of Connecticut's efforts to implement the ambitious initiatives that its PFAS Action Plan recommends.
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http://dx.doi.org/10.1016/j.scitotenv.2021.146192DOI Listing
July 2021

Effects of Dangguixu-san in patients with acute lateral ankle sprain: a randomized controlled trial.

Trials 2021 Mar 4;22(1):184. Epub 2021 Mar 4.

Department of Nursing, Christian College of Nursing, Gwangju City, 61662, Republic of Korea.

Background: Dangguixu-san (DS), a herbal extract, is widely used in Korean medicine to treat pain and swelling caused by ankle sprain. However, there is insufficient evidence regarding the effects of DS on ankle sprains. Accordingly, we assessed the efficacy and safety of DS for the treatment of acute lateral ankle sprain (ALAS).

Methods: This study was a multicenter (two Korean hospitals), randomized, double-blind, placebo-controlled, parallel-arm clinical trial with a 1:1 allocation ratio that included a per-protocol analysis and sub-analysis based on symptom severity. Forty-eight participants (n = 28 at Semyung University Korean Medicine Hospital in Chungju; n = 20 at DongShin University Gwangju Korean Medicine Hospital) with grade I or II ALAS that occurred within 72 h before enrollment were randomized to a DS (n = 24) or placebo (n = 24) group. Both groups received acupuncture treatment once daily for 5 consecutive days and the trial medication (DS/placebo capsule) three times a day for 7 consecutive days. Primary (visual analog scale [VAS] scores for pain) and secondary (Foot and Ankle Outcome Scores [FAOS], edema, and European Quality of Life Five-Dimension-Five-Level Scale [EQ-5D-5L] scores) outcome measures were recorded at baseline (week 0), the end of the intervention (week 1), and 4 weeks after treatment completion (week 5).

Results: Forty-six participants completed the trial (n = 23 each). Changes in VAS scores, FAOS Symptom/Rigidity, and FAOS Ache from week 1 to week 5 showed significant differences between the two groups. Sub-analyses showed significant differences in changes of FAOS Ache (week 0 to week 5) and VAS scores, total FAOS, and EQ-5D-5L scores (week 1 to week 5) between the two subgroups (grade II). There were no adverse events and significant negative changes in clinical laboratory parameters in both groups.

Conclusions: Overall, the results of this study are in favor of DS combined with acupuncture and suggest that DS combined with acupuncture is a safe treatment with positive long-term effects in terms of pain reduction and symptom alleviation in patients with grade I or II ALAS.

Trial Registration: Clinical Research Information Service KCT0002374 . Registered on July 11, 2017; retrospectively registered.
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http://dx.doi.org/10.1186/s13063-021-05135-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7934479PMC
March 2021

Short-term treatment outcomes and safety of two representative brands of the fifth-generation silicone gel-filled breast implants in Korea.

J Plast Surg Hand Surg 2021 Mar 4:1-9. Epub 2021 Mar 4.

The W Clinic, Seoul, Korea.

It is allegedly reported that the BellaGel SmoothFine (HansBiomed Co. Ltd., Seoul, Korea) and Motiva Ergonomix (Establishment Labs Holdings Inc., Alajuela, Costa Rica) are representative brands of a microtextured breast implant in Korea. We compared short-term safety outcomes between them. We evaluated the patients who received breast augmentation using the BellaGel SmoothFine ( = 264) or the Motiva Ergonomix™ ( = 76) for aesthetic purposes and those with available medical records. They were followed up during a mean period of 122.11 ± 95.37 (4-477) and 126.80 ± 116.29 (13-534) days in the corresponding order. Early seroma occurred at an incidence of 1.89 and 5.26% following breast augmentation using the BellaGel SmoothFine and the Motiva Ergonomix, respectively. This difference reached statistical significance ( < 0.05). Of note, CC occurred at an incidence of 2.27 and 0.00% in the corresponding order. Cumulative incidences of postoperative complications depending on the type of breast implants showed no significant difference; statistical significance was analyzed using the log-rank test (χ = 1.71,  = 1,  = 0.19). Cumulative survival of the breast implant is shown in Table 3; the Motiva Ergonomix™ showed a longer survival as compared with the BellaGel SmoothFine (130.13 ± 13.70 vs. 120.45 ± 5.76 days). In conclusion, we describe short-term treatment outcomes and safety of an implant-based breast augmentation using two representative brands of the fifth-generation silicone gel-filled breast implants in Korean women.
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http://dx.doi.org/10.1080/2000656X.2021.1888744DOI Listing
March 2021

Leukotriene B4 receptors contribute to house dust mite-induced eosinophilic airway inflammation via TH2 cytokine production.

BMB Rep 2021 Mar;54(3):182-187

Departments of Life Sciences, College of Life Sciences, Korea University, Seoul 02841, Korea.

Leukotriene B4 (LTB4) is a lipid mediator of inflammation that is generated from arachidonic acid via the 5-lipoxygenase pathway. Previous studies have reported that the receptors of LTB4, BLT1, and BLT2 play mediatory roles in the allergic airway inflammation induced by ovalbumin (OVA). However, considering that house dust mites (HDMs) are the most prevalent allergen and well-known risk factor for asthmatic allergies, we are interested in elucidating the contributory roles of BLT1/2 in HDMinduced allergic airway inflammation. Our aim in this study was to investigate whether BLT1/2 play any roles in HDM-induced allergic airway inflammation. In this study, we observed that the levels of ligands for BLT1/2 [LTB4 and 12(S)-HETE (12(S)- hydroxyeicosatetraenoic acid)] were significantly increased in bronchoalveolar lavage fluid (BALF) after HDM challenge. Blockade of BLT1 or BLT2 as well as of 5-lipoxygenase (5-LO) or 12-lipoxygenase (12-LO) markedly suppressed the production of TH2 cytokines (IL-4, IL-5, and IL-13) and alleviated lung inflammation and mucus secretion in an HDM-induced eosinophilic airway-inflammation mouse model. Together, these results indicate that the 5-/12-LO-BLT1/2 cascade plays a role in HDMinduced airway inflammation by mediating the production of TH2 cytokines. Our findings suggest that BLT1/2 may be a potential therapeutic target for patients with HDM-induced allergic asthma. [BMB Reports 2021; 54(3): 182-187].
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8016659PMC
March 2021

Effects of different wavelengths of invasive laser acupuncture on chronic non-specific low back pain: a study protocol for a pilot randomized controlled trial.

Trials 2021 Feb 5;22(1):118. Epub 2021 Feb 5.

Department of Nursing, Christian College of Nursing, 6 Baekseo-ro 70 beon-gil, Nam-gu, Gwangju City, 61662, Republic of Korea.

Background: Chronic non-specific low back pain (CLBP) is a common musculoskeletal disorder for which patients seek complementary and alternative medical treatments, including laser acupuncture (LA). Invasive LA (ILA) involves the simultaneous application of invasive acupuncture treatment at acupoints and focused laser irradiation. The efficacy of ILA for CLBP remains controversial owing to the insufficient clinical trial data. We intend to obtain basic data regarding the efficacy and safety of ILA for CLBP by comparing the effects of different wavelengths of ILA on CLBP.

Methods: This will be a prospective, patient-blinded, parallel-arm, single-center (DongShin University Gwangju Korean Medicine Hospital, Republic of Korea), pilot randomized controlled clinical trial. Forty-five participants with CLBP will be randomized in equal numbers into the control, 650-nm ILA (650 ILA), or 830-nm ILA (830 ILA) group. The control group will receive sham ILA for 10 min and real electroacupuncture (EA) for 10 min. The 650 and 830 ILA groups will receive real ILA (i.e., 650 ILA group, 650-nm wavelength; 830 ILA group, 830-nm wavelength) for 10 min and real EA for 10 min once/day, twice a week for 4 weeks, at bilateral Shenshu (BL23), Qihaishu (BL24), Dachangshu (BL25), and Huantiao (GB30). The primary outcome will be an improvement in pain intensity assessed using the visual analog scale. Scores in the Korean version of the Oswestry Disability Index and the European Quality of Life Five Dimension Five Level scale will be recorded as secondary outcome measures. All scores will be recorded at baseline (before intervention), 4 weeks after the first intervention (at the end of the intervention), and 4 weeks after completion of the intervention.

Discussion: The study is expected to provide preliminary evidence regarding the efficacy, safety, and usefulness of ILA for the treatment of CLBP.

Trial Registration: This trial was registered with the Clinical Research Information Service (registration No. KCT0004610 ; http://cris.nih.go.kr ). Registered on 7 January 2020.
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http://dx.doi.org/10.1186/s13063-021-05038-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7863497PMC
February 2021

Measuring temperature heterogeneities during solar-photothermal heating using quantum dot nanothermometry.

Analyst 2021 Mar 3;146(6):2048-2056. Epub 2021 Feb 3.

Department of Chemical and Environmental Engineering and Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT), Yale University, 17 Hillhouse Ave, New Haven, Connecticut 06511, USA.

Small metallic nanoparticles with appropriate surface plasmon resonance frequencies can be extremely efficient absorbers of solar radiation. This efficient absorption can lead to localized heating and highly heterogeneous temperatures. These unique optical properties have inspired research into the development of environmentally relevant solar-to-heat conversion technologies that are based on the light absorption of nanomaterials. The development of robust, reliable, and straight-forward techniques for measuring spatially resolved temperatures in photothermally heated systems can be an indispensable tool to aid future work in this area. Herein, we consider the application of a fluorescent technique that can measure spatially resolved temperatures in solar photothermal systems using CdSe quantum dots (<10 nm diameter). The local temperature of the quantum dot can be determined by monitoring the shift in its fluorescence wavelength resulting from the dilatation of the lattice with increasing temperature. To exploit this property, we fabricated Au nanorod-quantum dot architectures using linkers of varying lengths, and measured the light induced temperature change increasing more rapidly closer to the surface of an Au nanorod. We also compared the effect of Au nanorod coatings and found that silica coating leads to higher overall temperatures compared to organic stabilized Au nanorods.
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http://dx.doi.org/10.1039/d0an02258fDOI Listing
March 2021

Unusual piezochromic fluorescence of a distyrylpyrazine derivative crystals: phase transition through [2 + 2] photocycloaddition under UV irradiation.

Sci Rep 2021 Feb 2;11(1):2762. Epub 2021 Feb 2.

Department of Polymer Science and Engineering, School of Applied Chemical Engineering, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Daegu, 702-701, Korea.

The piezochromic fluorescence (FL) of a distyrylpyrazine derivative, 2,3-diisocyano-5,6-distyrylpyrazine (DSP), was investigated in this study. Depending on the recrystallization method, DSP afforded two different crystals with green and orange FL emission. The orange color FL emission crystal (O-form) was easily converted to the green color FL emission one (G-form) by manual grinding. The G-form was also converted to a slightly different orange color FL emission crystal (RO-form) by a weak UV irradiation. When the RO-form was ground again, the G-form was regenerated. The FL colors changed between the G- and RO-forms over several ten times by repeated mechanical grinding and UV irradiation. The FL, UV-visible, H-NMR and XRD results showed that the O (or RO)-to-G transformation induced by mechanical stress results from the change of degree of molecular stacking from dense molecular stacking structure to relatively loose molecular stacking structure, whereas the G-to-RO reconversion by UV irradiation results from return to dense molecular stacking structure again due to lattice movement (lattice slipping) allowed by photocycloaddition in solid-state.
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http://dx.doi.org/10.1038/s41598-021-81562-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7854636PMC
February 2021

Improvement of PR8-Derived Recombinant Clade 2.3.4.4c H5N6 Vaccine Strains by Optimization of Internal Genes and H103Y Mutation of Hemagglutinin.

Vaccines (Basel) 2020 Dec 20;8(4). Epub 2020 Dec 20.

Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea.

Clade 2.3.4.4c H5N6 avian influenza A viruses (AIVs) may have originally adapted to infect chickens and have caused highly pathogenic avian influenza (HPAI) in poultry and human fatalities. Although A/Puerto Rico/8/1934 (H1N1) (PR8)-derived recombinant clade 2.3.4.4c H5N6 vaccine strains have been effective in embryonated chicken eggs-based vaccine production system, they need to be improved in terms of immunogenicity and potential mammalian pathogenicity. We replaced the PB2 gene alone or the PB2 (polymerase basic protein 2), NP (nucleoprotein), M (matrix protein) and NS (non-structural protein) genes together in the PR8 strain with corresponding genes from AIVs with low pathogenicity to remove mammalian pathogenicity and to match CD8+ T cell epitopes with contemporary HPAI viruses, respectively, without loss of viral fitness. Additionally, we tested the effect of the H103Y mutation of hemagglutinin (HA) on antigen productivity, mammalian pathogenicity and heat/acid stability. The replacement of PB2 genes and the H103Y mutation reduced the mammalian pathogenicity but increased the antigen productivity of the recombinant vaccine strains. The H103Y mutation increased heat stability but unexpectedly decreased acid stability, probably resulting in increased activation pH for HA. Interestingly, vaccination with inactivated recombinant virus with replaced NP, M and NS genes halted challenge virus shedding earlier than the recombinant vaccine without internal genes replacement. In conclusion, we successfully generated recombinant clade 2.3.4.4c H5N6 vaccine strains that were less pathogenic to mammals and more productive and heat stable than conventional PR8-derived recombinant strains by optimization of internal genes and the H103Y mutation of HA.
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http://dx.doi.org/10.3390/vaccines8040781DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7766170PMC
December 2020

Design of Multi-Stage Roll Die Forming Process for Drum Clutch with Artificial Neural Network.

Materials (Basel) 2020 Dec 25;14(1). Epub 2020 Dec 25.

Department of Nanomechatronics Engineering, Pusan National University, 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 46241, Korea.

The multi-stage roll die forming (RDF) process is a plastic forming process that can manufacture a transmission part with a complex shape, such as a drum clutch, by using a die set with rotational rolls. However, it is difficult to satisfy dimensional accuracy because of spring-back and unfilling. The purpose of this study is to design a multi-stage RDF process for the manufacturing of a drum clutch to improve dimensional accuracy using an artificial neural network (ANN). Finite element (FE) simulation of the multi-stage RDF process is performed to predict the dimensional accuracy according to various clearances for each stage. Moreover, the ANN is used to determine the relationship between the clearance and dimensional accuracy of the drum clutch to reduce the number of FE simulation. The results of the FE simulation and ANN are used to determine the optimal clearance for each stage of the RDF process. Finally, the drum clutch is fabricated using the determined conditions. The experimental results are in good agreement with the results of FE simulation from the aspect of outer diameter, inner diameter, thickness of outer tooth, thickness of inner tooth, and face thickness of tooth.
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http://dx.doi.org/10.3390/ma14010069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7795483PMC
December 2020

Hand-ground fullerene-nanodiamond composite for photosensitized water treatment and photodynamic cancer therapy.

J Colloid Interface Sci 2021 Apr 11;587:101-109. Epub 2020 Dec 11.

School of Chemical and Biological Engineering, Institute of Chemical Process (ICP), and Institute of Engineering Research, Seoul National University, Seoul 08826, Republic of Korea. Electronic address:

The unique capability of fullerene (C) to absorb light and generate reactive oxygen species (ROS) has been extensively studied for photosensitized water treatment and cancer therapy. Various material synthesis strategies have been proposed in parallel to overcome its intrinsic hydrophobicity and to enhance availability in water and physiological media. We present here a strikingly simple approach to make C available to these applications by hand-grinding dry C powder with nanodiamond (ND) using a mortar and pestle. The resulting ND-C composite was found to form a stable aqueous colloidal suspension and efficiently drive photosensitized production of ROS under visible light illumination. ND-C rapidly adsorbed and oxidized organic contaminants by photogenerated ROS. In the experiments for photodynamic cancer therapy, ND-C was internalized by cancer cells and induced cell apoptosis without noticeable toxicity. Treatment of tumor-bearing mice with ND-C and light irradiation resulted in tumor shrinkage and prolonged survival time.
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http://dx.doi.org/10.1016/j.jcis.2020.12.020DOI Listing
April 2021

Cognitive Improvement Effects of Electroacupuncture Combined with Computer-Based Cognitive Rehabilitation in Patients with Mild Cognitive Impairment: A Randomized Controlled Trial.

Brain Sci 2020 Dec 14;10(12). Epub 2020 Dec 14.

Department of Nursing, Christian College of Nursing, Gwangju City 61662, Korea.

This outcome assessor-blinded, randomized controlled clinical trial investigated the effects of electroacupuncture combined with computer-based cognitive rehabilitation (EA-CCR) on mild cognitive impairment (MCI). A per-protocol analysis was employed to compare the efficacy of EA-CCR to that of computer-based cognitive rehabilitation (CCR). Thirty-two patients with MCI completed the trial (EA-CCR group, 16; CCR group, 16). Patients received EA-CCR or CCR treatment once daily three days per week for eight weeks. Outcome (primary, ADAS-K-cog; secondary, MoCA-K, CES-D, K-ADL, K-IADL, and EQ-5D-5L) measurements were performed at baseline (week 0), at the end of the intervention (week 8), and at 12 weeks after completion of the intervention (week 20). Both groups showed significant changes in ADAS-K-cog score (EA-CCR, < 0.001; CCR, < 0.001) and MoCA-K (EA-CCR, < 0.001; CCR, < 0.001). Only the EA-CCR group had a significant change in CES-D ( = 0.024). No significant differences in outcomes and in the results of a subanalysis based on age were noted between the groups. These results indicate that EA-CCR and CCR have beneficial effects on improving cognitive function in patients with MCI. However, electroacupuncture in EA-CCR showed no positive add-on effects on improving cognitive function, depression, activities of daily living, and quality of life in patients with MCI.
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http://dx.doi.org/10.3390/brainsci10120984DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7765117PMC
December 2020

Leukotriene B receptors play critical roles in house dust mites-induced neutrophilic airway inflammation and IL-17 production.

Biochem Biophys Res Commun 2021 01 28;534:646-652. Epub 2020 Nov 28.

Department of Biotechnology, College of Life Sciences, Korea University, Seoul, 02841, Republic of Korea. Electronic address:

Increased levels of neutrophils in bronchoalveolar lavage fluid (BALF) were associated with asthma severity. As leukotriene B4 (LTB) is a principal chemoattractant molecule for neutrophils, its receptors, BLT1 and BLT2, may contribute to neutrophil-dominant airway inflammation. In the present study, we established a mouse model of steroid-resistant, neutrophil-dominant airway inflammation by house dust mite (HDM)/lipopolysaccharide (LPS) sensitization and HDM challenge, and we investigated whether BLT1/BLT2 signaling was associated with the development of neutrophilic airway inflammation. Blockade of BLT1 or BLT2 significantly suppressed airway inflammation and IL-17 production in this mouse model. The 5-LO and 12-LO enzymes, which catalyze the synthesis of BLT1/BLT2 ligands, were also critically associated with neutrophil-dominant airway inflammation and the synthesis of IL-17. Collectively, our results suggest that the 5-/12-LO-BLT1/BLT2-linked cascade significantly contributes to neutrophil-dominant severe airway inflammation via IL-17 synthesis in HDM-induced neutrophilic asthma.
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http://dx.doi.org/10.1016/j.bbrc.2020.11.027DOI Listing
January 2021

Intrapore energy barriers govern ion transport and selectivity of desalination membranes.

Sci Adv 2020 Nov 25;6(48). Epub 2020 Nov 25.

Department of Chemical and Environmental Engineering, Yale University, New Haven, CT 06511, USA.

State-of-the-art desalination membranes exhibit high water-salt selectivity, but their ability to discriminate between ions is limited. Elucidating the fundamental mechanisms underlying ion transport and selectivity in subnanometer pores is therefore imperative for the development of ion-selective membranes. Here, we compare the overall energy barrier for salt transport and energy barriers for individual ion transport, showing that cations and anions traverse the membrane pore in an independent manner. Supported by density functional theory simulations, we demonstrate that electrostatic interactions between permeating counterion and fixed charges on the membrane substantially hinder intrapore diffusion. Furthermore, using quartz crystal microbalance, we break down the contributions of partitioning at the pore mouth and intrapore diffusion to the overall energy barrier for salt transport. Overall, our results indicate that intrapore diffusion governs salt transport through subnanometer pores due to ion-pore wall interactions, providing the scientific base for the design of membranes with high ion-ion selectivity.
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http://dx.doi.org/10.1126/sciadv.abd9045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7688318PMC
November 2020

Astrocytic pyruvate dehydrogenase kinase-2 is involved in hypothalamic inflammation in mouse models of diabetes.

Nat Commun 2020 11 20;11(1):5906. Epub 2020 Nov 20.

BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science and Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.

Hypothalamic inflammation plays an important role in disrupting feeding behavior and energy homeostasis as well as in the pathogenesis of obesity and diabetes. Here, we show that pyruvate dehydrogenase kinase (PDK)-2 plays a role in hypothalamic inflammation and its sequelae in mouse models of diabetes. Cell type-specific genetic ablation and pharmacological inhibition of PDK2 in hypothalamic astrocytes suggest that hypothalamic astrocytes are involved in the diabetic phenotype. We also show that the PDK2-lactic acid axis plays a regulatory role in the observed metabolic imbalance and hypothalamic inflammation in mouse primary astrocyte and organotypic cultures, through the AMPK signaling pathway and neuropeptidergic circuitry governing feeding behavior. Our findings reveal that PDK2 ablation or inhibition in mouse astrocytes attenuates diabetes-induced hypothalamic inflammation and subsequent alterations in feeding behavior.
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http://dx.doi.org/10.1038/s41467-020-19576-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7680139PMC
November 2020

Cobalt Single Atoms on Tetrapyridomacrocyclic Support for Efficient Peroxymonosulfate Activation.

Environ Sci Technol 2021 01 19;55(2):1242-1250. Epub 2020 Nov 19.

Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520-8286, United States.

Transition-metal catalysts that can efficiently activate peroxide bonds have been extensively pursued for various applications including environmental remediation, chemical synthesis, and sensing. Here, we present pyridine-coordinated Co single atoms embedded in a polyaromatic macrostructure as a highly efficient peroxide-activation catalyst. The efficient catalytic production of reactive radicals through peroxymonosulfate activation was demonstrated by the rapid removal of model aqueous pollutants of environmental and public health concerns such as bisphenol A, without pH limitation and Co leaching. The turnover frequency of the newly synthesized Co single-atom catalyst bound to tetrapyridomacrocyclic ligands was found to be 2 to 4 orders of magnitude greater than that of benchmark homogeneous (Co) and nanoparticulate (CoO) catalysts. Experimental results and density functional theory simulation suggest that the abundant π-conjugation in the polyaromatic support and strong metal-support electronic interaction allow the catalysts to effectively adsorb and activate the peroxide precursor. We further loaded the catalysts onto a widely used poly(vinylidene fluoride) microfiltration membrane and demonstrated that the model pollutants were oxidatively removed as they simply passed through the filter, suggesting the promise of utilizing this novel catalyst for realistic applications.
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http://dx.doi.org/10.1021/acs.est.0c06086DOI Listing
January 2021

Astrocytes in the Ventrolateral Preoptic Area Promote Sleep.

J Neurosci 2020 11 16;40(47):8994-9011. Epub 2020 Oct 16.

Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea

Although ventrolateral preoptic (VLPO) nucleus is regarded as a center for sleep promotion, the exact mechanisms underlying the sleep regulation are unknown. Here, we used optogenetic tools to identify the key roles of VLPO astrocytes in sleep promotion. Optogenetic stimulation of VLPO astrocytes increased sleep duration in the active phase in naturally sleep-waking adult male rats ( = 6); it also increased the extracellular ATP concentration ( = 3) and c-Fos expression ( = 3-4) in neurons within the VLPO. microdialysis analyses revealed an increase in the activity of VLPO astrocytes and ATP levels during sleep states ( = 4). Moreover, metabolic inhibition of VLPO astrocytes reduced ATP levels ( = 4) and diminished sleep duration ( = 4). We further show that tissue-nonspecific alkaline phosphatase (TNAP), an ATP-degrading enzyme, plays a key role in mediating the somnogenic effects of ATP released from astrocytes ( = 5). An appropriate sample size for all experiments was based on statistical power calculations. Our results, taken together, indicate that astrocyte-derived ATP may be hydrolyzed into adenosine by TNAP, which may in turn act on VLPO neurons to promote sleep. Glia have recently been at the forefront of neuroscience research. Emerging evidence illustrates that astrocytes, the most abundant glial cell type, are the functional determinants for fates of neurons and other glial cells in the central nervous system. In this study, we newly identified the pivotal role of hypothalamic ventrolateral preoptic (VLPO) astrocytes in the sleep regulation, and provide novel insights into the mechanisms underlying the astrocyte-mediated sleep regulation.
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http://dx.doi.org/10.1523/JNEUROSCI.1486-20.2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7673007PMC
November 2020

Interrogation of kinase genetic interactions provides a global view of PAK1-mediated signal transduction pathways.

J Biol Chem 2020 12 15;295(50):16906-16919. Epub 2020 Oct 15.

Department of Pharmacology, Brain Science and Engineering Institute, and Department of Biomedical Sciences, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, South Korea. Electronic address:

Kinases are critical components of intracellular signaling pathways and have been extensively investigated with regard to their roles in cancer. p21-activated kinase-1 (PAK1) is a serine/threonine kinase that has been previously implicated in numerous biological processes, such as cell migration, cell cycle progression, cell motility, invasion, and angiogenesis, in glioma and other cancers. However, the signaling network linked to PAK1 is not fully defined. We previously reported a large-scale yeast genetic interaction screen using toxicity as a readout to identify candidate genetic interactions. transformation of the gene into 4,653 homozygous diploid yeast deletion mutants identified ∼400 candidates that suppressed yeast toxicity. Here we selected 19 candidate genetic interactions that had human orthologs and were expressed in glioma for further examination in mammalian cells, brain slice cultures, and orthotopic glioma models. RNAi and pharmacological inhibition of potential interactors confirmed that , , , , , , and regulate PAK1-induced cell migration and revealed the importance of genes related to the mitotic spindle, proteolysis, autophagy, and metabolism in PAK1-mediated glioma cell migration, drug resistance, and proliferation. AKT1 was further identified as a downstream mediator of the - genetic interaction. Taken together, these data provide a global view of PAK1-mediated signal transduction pathways and point to potential new drug targets for glioma therapy.
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http://dx.doi.org/10.1074/jbc.RA120.014831DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7863907PMC
December 2020

Analysis of medical services provided to patients with ankle sprains in Korea between 2015 and 2017: a cross-sectional study of the health insurance review and assessment service national patient sample database.

BMJ Open 2020 09 24;10(9):e039297. Epub 2020 Sep 24.

Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Gangnam-gu, Republic of Korea

Objectives: To provide useful information for policy-makers and clinicians by analysing the medical service use-divided into Western medicine (WM) and Korean medicine (KM)-of patients with ankle sprains in South Korea between 2015 and 2017.

Design: Cross-sectional, retrospective, observational study.

Setting: Tertiary hospitals, WM hospitals, WM clinics, KM hospitals, KM clinics and others in South Korea.

Participants: We analysed claim data and patient information from the 2015 to 2017 Health Insurance Review and Assessment National Patient Sample (HIRA-NPS) dataset, including 151 415 patients diagnosed with a 'dislocation, sprain and strain of joints and ligaments at ankle and foot level' (10th revision of the International Statistical Classification of Diseases code S93) who used medical services at least once in 3 years between January 2015 and December 2017 in South Korea.

Primary And Secondary Outcome Measures: Cost of medical care, number of consultations, type of institution visited, types of treatment.

Results: There were 160 200 consultations and 53 044 patients in 2015, 149 956 consultations and 50 830 patients in 2016 and 140 651 consultations and 47 541 patients in 2017. The total treatment costs were US$3 355 044.21, US$3 245 827.70 and US$3 128 938.46 in 2015, 2016 and 2017, respectively. The most common age was 10-19 years. The most frequent type of visit was KM outpatient visit (56%). Physiotherapy was most common in WM outpatient visits, while acupuncture was most common in KM visits. Most patients used one institution, rather than alternating between WM and KM.

Conclusions: By identifying the trends and costs of treatment methods used for ankle sprains and comparing WM and KM, our data provide basic information for future health policy-making. In addition, the duality of the Korean medical system is highlighted as a possible cause of increased costs.
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http://dx.doi.org/10.1136/bmjopen-2020-039297DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7517580PMC
September 2020

Augmented Biodegradation of Textile Azo Dye Effluents by Plant Endophytes: A Sustainable, Eco-Friendly Alternative.

Curr Microbiol 2020 Nov 19;77(11):3240-3255. Epub 2020 Sep 19.

Department of Chemical Engineering, Yeungnam University, 214-1, Dae-hakro 280, Gyeongsan, 712-749, Gyeongbuk, Korea.

Textile industry consumes a large proportion of available water and releases huge amounts of toxic azo dye effluents, leading to an inevitable situation of acute environmental pollution that has been a significant threat to mankind. Decolorization or detoxification of harmful azo dyes has become a global priority to overcome the disastrous consequences and salvage the ecosystem. Biodegradation of textile azo dyes by endophytes stands to be a lucrative and viable alternative over conventional physico-chemical methods, owing to their eco-friendliness, cost-competitive and non-toxic nature. Especially, plant endophytic microbes exhibit promising biodegradation potential which has wired up the effective removal of textile azo dyes, attributing to their ability to produce dye degrading enzymes, laccases, peroxidases and azoreductases. Although both bacterial and fungal endophytes have been tried for azo dye degradation, endophytic fungi find broader application over bacteria. Despite of the advancements made in microbe-mediated biodegradation, there is still a need to fill the gap in lab to in situ translation of biodegradation research. This review concisely accentuates the xenobiotics of textile azo dyes and microbial mechanisms of biodegradation of textile azo dyes, positing plant endophytic community, especially bacterial and fungal endophytes as the potential dye degraders, highlighting currently reported dye degrading endophytic species.
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http://dx.doi.org/10.1007/s00284-020-02202-0DOI Listing
November 2020

CO Curing Efficiency for Cement Paste and Mortars Produced by a Low Water-to-Cement Ratio.

Materials (Basel) 2020 Sep 2;13(17). Epub 2020 Sep 2.

Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.

Curing by CO is a way to utilize CO to reduce greenhouse gas emissions. Placing early-age cement paste in a CO chamber or pressure vessel accelerates its strength development. Cement carbonation is attributed to the quickened strength development, and CO uptake can be quantitatively evaluated by measuring CO gas pressure loss in the pressure vessel. A decrease in CO gas pressure is observed with all cement pastes and mortar samples regardless of the mix proportion and the casting method; one method involves compacting a low water-to-cement ratio mix, and the other method comprises a normal mix consolidated in a mold. The efficiency of the CO curing is superior when a 20% concentration of CO gas is supplied at a relative humidity of 75%. CO uptake in specimens with the same CO curing condition is different for each specimen size. As the specimen scale is larger, the depth of carbonation is smaller. Incorporating colloidal silica enhances the carbonation as well as the hydration of cement, which results in contributing to the increase in the 28-day strength.
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http://dx.doi.org/10.3390/ma13173883DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7503678PMC
September 2020

Enhanced Electrochemical Properties and OER Performances by Cu Substitution in NiCoO Spinel Structure.

Nanomaterials (Basel) 2020 Aug 31;10(9). Epub 2020 Aug 31.

Department of Chemistry, College of Natural Sciences, Yeungnam University, Gyeongsan 38541, Gyeongbuk, Korea.

In order to improve the electrochemical performance of the NiCoO material, Ni ions were partially substituted with Cu ions having excellent reducing ability. All of the electrodes were fabricated by growing the NiCuCoO electrode spinel-structural active materials onto the graphite felt (GF). Five types of electrodes, NiCoO/GF, NiCuCoO/GF, NiCuCoO/GF, NiCuCoO/GF, and NiCuCoO/GF, were prepared for application to the oxygen evolution reaction (OER). As Cu ions were substituted, the electrochemical performances of the NiCoO-based structures were improved, and eventually the OER activities were also greatly increased. In particular, the NiCuCoO/GF electrode exhibited the best OER activity in a 1.0 M KOH alkaline electrolyte: the cell voltage required to reach a current density of 10 mA cm was only 1.74 V (η = 509 mV), and a low Tafel slope of 119 mV dec was obtained. X-ray photoelectron spectroscopy (XPS) analysis of NiCuCoO/GF before and after OER revealed that oxygen vacancies are formed around active metals by the insertion of Cu ions, which act as OH-adsorption sites, resulting in high OER activity. Additionally, the stability of the NiCuCoO/GF electrode was demonstrated through 1000th repeated OER acceleration stability tests with a high faradaic efficiency of 94.3%.
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http://dx.doi.org/10.3390/nano10091727DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7558615PMC
August 2020

Mechanism of Heterogeneous Fenton Reaction Kinetics Enhancement under Nanoscale Spatial Confinement.

Environ Sci Technol 2020 09 12;54(17):10868-10875. Epub 2020 Aug 12.

Department of Chemical and Environmental Engineering, Yale University, 17 Hillhouse Avenue, New Haven, Connecticut 06511, United States.

Nanoscale catalysts that can enable Fenton-like chemistry and produce reactive radicals from hydrogen peroxide activation have been extensively studied in order to overcome the limitations of homogeneous Fenton processes. Despite several advantageous features, limitation in mass transfer of short-lived radical species is an inherent drawback of the heterogeneous system. Here, we present a mechanistic foundation for the way spatial confinement of Fenton chemistry at the nanoscale can significantly enhance the kinetics of radical-mediated oxidation reactions-pollutant degradation in particular. We synthesized a series of FeO-functionalized nanoreactors with precise pore dimensions, based on an anodized aluminum oxide template, to enable quantitative analysis of nanoconfinement effects. Combined with computational simulation of spatial distribution of radicals, we found that hydroxyl radical concentration was strongly dependent on the distance from the surface of Fenton catalysts. This distance dependency significantly influences the gross reaction kinetics and accounts for the observed nanoconfinement effects. We further found that a length scale below 25 nm is critical to avoid the limitation of short-lived species diffusion and achieve kinetics that are orders of magnitude faster than those obtained in a batch suspension of heterogeneous catalysts. These findings suggest a new strategy to develop an innovative heterogeneous catalytic system with the most effective use of hydroxyl radicals in oxidation treatment scenarios.
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http://dx.doi.org/10.1021/acs.est.0c02192DOI Listing
September 2020

Elucidation of Mechanism for Ligand Efficacy at Leukotriene B Receptor 2 (BLT2).

ACS Med Chem Lett 2020 Aug 14;11(8):1529-1534. Epub 2020 Jul 14.

Department of Bioinformatics, Korea University, 2511 Sejong-ro, Sejong 30019, Republic of Korea.

G protein-coupled receptors (GPCRs) have always been important drug targets in the pharmaceutical industry. One major question for the current GPCR drug discovery is how drugs have distinct efficacies at the same GPCR target. Related to this question, we studied how different ligands can have disparate efficacies at Leukotriene B receptor (BLT2). By using molecular modeling studies, we predicted that Tyr271 located at TM6 of BLT2 performs as a key trigger for its activation and verified the prediction by site-directed mutagenesis, chemotactic motility studies, which included a chemical derivative of agonist CAY10583. We further identified Asn275 located at TM6 as a weak activation trigger in BLT2 and performed double mutation studies to confirm our computational results. Our results provide strong evidence for the exact mechanism of ligand efficacy at BLT2.
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http://dx.doi.org/10.1021/acsmedchemlett.0c00065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7430951PMC
August 2020
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