18 results on '"Minjeong Cha"'
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2. Unifying structural descriptors for biological and bioinspired nanoscale complexes.
- Author
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Minjeong Cha, Emine Sumeyra Turali-Emre, Xiongye Xiao, Ji-Young Kim, Paul Bogdan, J. Scott Vanepps, Angela Violi, and Nicholas A. Kotov
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- 2022
- Full Text
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3. Tapered chiral nanoparticles as broad-spectrum thermally stable antivirals for SARS-CoV-2 variants.
- Author
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Rui Gao, Xinxin Xu, Kumar, Prashant, Ye Liu, Hongyu Zhang, Xiao Guo, Maozhong Sun, Coiombari, Felippe Mariano, de Moura, André F., Changiong Hao, Ma, Jessica, Turali Emre, Emine Sumeyra, Minjeong Cha, Liguang Xu, Hua Kuang, Kotov, Nicholas A., and Chuanlai Xu
- Subjects
SARS-CoV-2 Omicron variant ,SARS-CoV-2 ,NANOPARTICLES ,ANTIVIRAL agents ,VIRAL mutation ,NANOPARTICLES manufacturing - Abstract
The incessant mutations of viruses, variable immune responses, and likely emergence of new viral threats necessitate multiple approaches to novel antiviral therapeutics. Furthermore, the new antiviral agents should have broad-spectrum activity and be environmentally stable. Here, we show that biocompatible tapered CuS nanoparticles (NPs) efficiently agglutinate coronaviruses with binding affinity dependent on the chirality of surface ligands and particle shape. Z-penicillamine-stabilized NPs with left-handed curved apexes display half-maximal inhibitory concentrations (IC
50 ) as low as 0.66 pM (1.4 ng/mL) and 0.57 pM (1.2 ng/mL) for pseudo-type SARS-CoV-2 viruses and wild-type Wuhan-1 SARS-CoV-2 viruses, respectively, which are about 1,100 times lower than those for antibodies (0.73 nM). Benefiting from strong NPs-protein interactions, the same particles are also effective against other strains of coronaviruses, such as HCoV-HKU1, HCoV-OC43, HCoV-NL63, and SARS-CoV-2 Omicron variants with IC50 values below 10 pM (21.8 ng/mL). Considering rapid response to outbreaks, exposure to elevated temperatures causes no change in the antiviral activity of NPs while anti-bodies are completely deactivated. Testing in mice indicates that the chirality-optimized NPs can serve as thermally stable analogs of antiviral biologics complementing the current spectrum of treatments. [ABSTRACT FROM AUTHOR]- Published
- 2024
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4. Direct-write 3D printing of plasmonic nanohelicoids by circularly polarized light.
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Ji-Young Kim, McGlothin, Connor, Minjeong Cha, Pfaffenberger, Zechariah J., Turali Emre, Emine Sumeyra, Wonjin Choi, Sanghoon Kim, Biteen, Julie S., and Kotov, Nicholas A.
- Subjects
THREE-dimensional printing ,PLASMONICS ,OPTICAL rotation ,SILVER nanoparticles ,NANOFABRICATION - Abstract
Chiral plasmonic surfaces with 3D "forests" from nanohelicoids should provide strong optical rotation due to alignment of helical axis with propagation vector of photons. However, such three-dimensional nanostructures also demand multi-step nanofabrication, which is incompatible with many substrates. Large-scale photonic patterns on polymeric and flexible substrates remain unattainable. Here, we demonstrate the substrate-tolerant direct-write printing and patterning of silver nanohelicoids with out-of-plane 3D orientation using circularly polarized light. Centimeter-scale chiral plasmonic surfaces can be produced within minutes using inexpensive medium-power lasers. The growth of nanohelicoids is driven by the symmetry-broken site-selective deposition and self-assembly of the silver nanoparticles (NPs). The ellipticity and wavelength of the incident photons control the local handedness and size of the printed nanohelicoids, which enables on-the-fly modulation of nanohelicoid chirality during direct writing and simple pathways to complex multifunctional metasurfaces. Processing simplicity, high polarization rotation, and fine spatial resolution of the light-driven printing of stand-up helicoids provide a rapid pathway to chiral plasmonic surfaces, accelerating the development of chiral photonics for health and information technologies. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Photonically active bowtie nanoassemblies with chirality continuum
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Prashant Kumar, Thi Vo, Minjeong Cha, Anastasia Visheratina, Ji-Young Kim, Wenqian Xu, Jonathan Schwartz, Alexander Simon, Daniel Katz, Valentin Paul Nicu, Emanuele Marino, Won Jin Choi, Michael Veksler, Si Chen, Christopher Murray, Robert Hovden, Sharon Glotzer, and Nicholas A. Kotov
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Multidisciplinary - Published
- 2023
6. Targeted Agglutination of Corona Virus by Tapered Chiral Nanoparticles
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Rui Gao, Xinxin Xu, Prashant Kumar, Ye Liu, Hongyu Zhang, Xiao Guo, maozhong sun, Felippe Colombari, André de Moura, changlong hao, Minjeong Cha, Emine Turali-Emre, Jessica Ma, Liguang Xu, hua kuang, Nicholas Kotov, and Chuanlai Xu
- Abstract
The emergence of new viral threats, wide applications of viruses in biotechnology and challenges associated with viral contamination necessitate multiple types of virustatic agents. Here, we show that highly biocompatible tapered CuS nanoparticles efficiently agglutinate COVID virus with binding affinity dependent on chirality of surface ligands and particle shape. L-penicillamine-stabilized nanoparticles with left-handed curved apexes display half-maximal inhibitory concentration as low as 0.57 pM for authentic SARS-CoV-2 viruses, which is ca 15 times greater than for antibodies. Exposure to elevated temperatures causes no change in activity or biocompatibility of nanoparticles while completely deactivating antibodies. Testing with mice indicates that the chirality-optimized nanoparticles can serve as analogs of high antiviral molecular weight biologics complementing the current spectrum of virustatic agents. Their thermal and chemical stability simplifies their applications in biomedical and biotechnological processes.
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- 2023
7. Direct Printing of Helical Metal Arrays by Circularly Polarized Light
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Ji Young Kim, Connor McGlothin, Minjeong Cha, Zechariah Pfaffenberger, Emine Turali Emre, Wonjin Choi, Sanghoon Kim, Julie Biteen, and Nicholas Kotov
- Abstract
Chiral metasurface with orthogonal nanohelical metal arrays provide strong optical rotation but demands multi-step nanofabrication at low-pressure and/or high-temperature conditions, which is incompatible with many substrates and high-throughput assessment. Submillimeter local photonic patterns with various optical polarization were also hitherto unattainable over the same substrate. Here, we demonstrate direct substrate-tolerant printing of silver nanohelicoids with a locally variable optical activity using circularly polarized light (CPL), producing centimeter-scale chiral metasurface within minutes. The light-illuminated sites on the substrate immersed in an aqueous silver ion solution are activated for heterogeneous nucleation at room temperature. Subsequent CPL-induced asymmetric site-selective deposition and self-assembly of the silver nanoparticles (NPs) sculpt the orthogonal silver helicoids at the interface as one-pot synthesis. The ellipticity and wavelength of the incident photons control the handedness and size of the printed silver helicoids, realizing on-the-fly modulation of optical polarization while printing local patterns. Processing simplicity, high polarization rotation, and fine spatial resolution of the light-driven printing can provide a pathway to the sustainable production of chiral plasmonic metasurfaces, accelerating the development of chiral photonics for health and information technologies.
- Published
- 2023
8. Voltage‐Modulated Untwist Deformations and Multispectral Optical Effects from Ion Intercalation into Chiral Ceramic Nanoparticles
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Xiao Shao, Cheng Zhu, Prashant Kumar, Yanan Wang, Jun Lu, Minjeong Cha, Lin Yao, Yuan Cao, Xiaoming Mao, Hendrik Heinz, and Nicholas A. Kotov
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Published
- 2023
9. Chiral phonons in microcrystals and nanofibrils of biomolecules
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Won Jin Choi, Keiichi Yano, Minjeong Cha, Felippe M. Colombari, Ji-Young Kim, Yichun Wang, Sang Hyun Lee, Kai Sun, John M. Kruger, André F. de Moura, and Nicholas A. Kotov
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Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Published
- 2022
10. Abstract 994: Chiroptical detection and mutation analysis of cancer-associated extracellular vesicles in microfluidic devices with oriented chiral nanoparticles
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Yoon-Tae Kang, Ji-Young Kim, Emine Sumeyra Turali-Emre, Hee-Jeong Jang, Minjeong Cha, Abha Kumari, Colin Palacios-Rolston, Chitra Subramanian, Emma Purcell, Sarah Owen, Chung-Man Lim, Rishindra Reddy, Shruthi Jolly, Nithya Ramnath, Nicholas A. Kotov, and Sunitha Nagrath
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Cancer Research ,Oncology - Abstract
Small extracellular vesicles, often termed as “exosomes” carry informative cargo containing proteins and lipids, reflective of their cellular origin. Thus, they are promising biomarkers for early diagnosis of cancer. However, conventional profiling methods like quantitative polymerase chain reaction (qPCR) require complex procedures, thereby limiting the analytical sensitivity of exosomes for liquid biopsies. Here, we demonstrate a sensitive microfluidic device (CDEXO) that isolates and profiles cancer-associated exosomes directly from blood plasma using assembled chiral gold nanoparticles (AuNPs). The unique changes in chiral signals are associated with specific biomolecules on the exosomes’ membranes. Thus, we can distinguish exosomes of lung cancer patients from those of healthy individuals and detect mutated EGFR proteins on the membrane. Hence, this low-cost microfluidic device is an attractive technique for rapid, sensitive, and versatile profiling of various extracellular vesicles. Methods: The top layer of CDEXO devices were fabricated by soft lithography using polydimethylsiloxane (PDMS). The bottom glass slide was functionalized with a layer-by-layer assembly of cationic poly(dimethyl diallyl ammonium chloride) and anionic polystyrene sulfonate. AuNPs were prepared by adding gold nanoplates to a growth solution. Next, AuNPs were conjugated with biotinylated Annexin-V, using Neutravidin-biotin chemistry. Exosomes were harvested from lung cancer cell lines (A549, H1650, H3255) and lung fibroblasts (MRC5) and spiked into the CDEXO chip. EDTA was used to release the captured exosomes and quantified using nanoparticle tracking analysis (NTA). CD spectra were measured by spectrometry. Imaging of AuNPs and exosomes were done using scanning electron microscope (SEM). Results: CDEXO captures cancer-associated exosomes with an efficiency of 81.1±1.5%. H3255 derived exosomes that exhibited EGFR point mutation showed the greatest change in spectral signals from the baseline, followed by A549 (wild type), H1650, (EGFR exon19 deletion) and MRC5 (healthy). The CD responses were measurable at exosome numbers as low as 100. Further validation with 19 lung cancer patients showed an average 40% change in chiral signals from isolated exosomes that were 5.6 times higher in patients than healthy donors. Conclusions: A microfluidic device with chiral AuNPs allows sensitive and accurate detection of lung cancer-associated exosomes by conjugation with Annexin V. The resulting strong CD peaks that arise from specific interactions between exosomal surface proteins and chiral AuNPs facilitate in-depth profiling of target exosomes, including EGFR mutation expression. Citation Format: Yoon-Tae Kang, Ji-Young Kim, Emine Sumeyra Turali-Emre, Hee-Jeong Jang, Minjeong Cha, Abha Kumari, Colin Palacios-Rolston, Chitra Subramanian, Emma Purcell, Sarah Owen, Chung-Man Lim, Rishindra Reddy, Shruthi Jolly, Nithya Ramnath, Nicholas A. Kotov, Sunitha Nagrath. Chiroptical detection and mutation analysis of cancer-associated extracellular vesicles in microfluidic devices with oriented chiral nanoparticles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 994.
- Published
- 2023
11. Photonically Active Bowtie Nanoassemblies with Chirality Continuum
- Author
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Nicholas Kotov, Prashant Kumar, Thi Vo, Minjeong Cha, Anastasia Visheratina, Ji-Young Kim, Wenqian Xu, Jonathan Schwartz, Alexander Simon, Daniel Katz, Emanuele Marino, Won Jin Choi, Si Chen, Christopher Murray, Robert Hovden, and Sharon Glotzer
- Abstract
Chirality is a geometrical property described by continuous mathematical functions.1–5 However, in chemical disciplines chirality is often treated as a binary left/right characteristic of molecules rather than a continuity of chiral shapes. While being theoretically possible, a family of stable chemical structures with the same shape and progressively tunable chirality is yet unknown. Here we present such structures in the form of nanostructured microparticles with anisotropic bowtie shape and widely tunable twist angle, pitch, size, thickness, and length. The self-limited assembly of the bowties enables high synthetic reproducibility, size monodispersity, and computational predictability of their geometries for different assembly conditions.6 The bowties nanoassemblies display multiple strong circular dichroism peaks originating from absorptive and scattering phenomena. Unlike classical chiral molecules, these particles display a continuum of chirality measures2 that correlate exponentially with the spectral positions of the circular dichroism peaks. Bowtie particles with variable polarization rotation were used to print photonically active metasurfaces with spectrally tunable positive/negative polarization signatures for light detection and ranging (LIDAR) devices.
- Published
- 2022
12. Long-term efficient organic photovoltaics based on quaternary bulk heterojunctions
- Author
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Doo-Hyun Ko, Hyun Hwi Lee, Minwoo Nam, Il Ki Han, Minjeong Cha, S. Joon Kwon, Kahyun Hur, Kyu-Tae Lee, and Jaehong Yoo
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Materials science ,Fullerene ,Organic solar cell ,Science ,General Physics and Astronomy ,Nanotechnology ,02 engineering and technology ,Conjugated system ,010402 general chemistry ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Polymer solar cell ,chemistry.chemical_classification ,Multidisciplinary ,business.industry ,Heterojunction ,General Chemistry ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Degradation (geology) ,Optoelectronics ,0210 nano-technology ,business - Abstract
A major impediment to the commercialization of organic photovoltaics (OPVs) is attaining long-term morphological stability of the bulk heterojunction (BHJ) layer. To secure the stability while pursuing optimized performance, multi-component BHJ-based OPVs have been strategically explored. Here we demonstrate the use of quaternary BHJs (q-BHJs) composed of two conjugated polymer donors and two fullerene acceptors as a novel platform to produce high-efficiency and long-term durable OPVs. A q-BHJ OPV (q-OPV) with an experimentally optimized composition exhibits an enhanced efficiency and extended operational lifetime than does the binary reference OPV. The q-OPV would retain more than 72% of its initial efficiency (for example, 8.42–6.06%) after a 1-year operation at an elevated temperature of 65 °C. This is superior to those of the state-of-the-art BHJ-based OPVs. We attribute the enhanced stability to the significant suppression of domain growth and phase separation between the components via kinetic trapping effect., Organic photovoltaics suffer from degradation. Here, Nam et al. develop a quaternary blend and fabricate devices which lose 28% of their initial efficiency after one year of operation at 65 °C.
- Published
- 2017
13. A Self-Reducible and Alcohol-Soluble Copper-Based Metal–Organic Decomposition Ink for Printed Electronics
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Sooncheol Jeong, Sanghun Cho, Seunghee Woo, Kyung-Tae Kang, Hyesuk Yem, Yoonhyun Kim, Mingyu Kang, Minjeong Cha, Yuanzhe Piao, and Dong-Hun Shin
- Subjects
Materials science ,Reducing atmosphere ,chemistry.chemical_element ,Copper ,body regions ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,visual_art ,Printed electronics ,Conductive ink ,visual_art.visual_art_medium ,Offset printing ,Organic chemistry ,General Materials Science ,Formate ,Alkanolamine ,Electrical conductor ,circulatory and respiratory physiology - Abstract
We report a novel method for the synthesis of a self-reducible (thermally reducible without a reducing atmosphere) and alcohol-soluble copper-based metal-organic decomposition (MOD) ink for printed electronics. Alcohol-solvent-based conductive inks are necessary for commercial printing processes such as reverse offset printing. We selected copper(II) formate as a precursor and alkanolamine (2-amino-2-methyl-1-propanol) as a ligand to make an alcohol-solvent-based conductive ink and to assist in the reduction reaction of copper(II) formate. In addition, a co-complexing agent (octylamine) and a sintering helper (hexanoic acid) were introduced to improve the metallic copper film. The specific resistivity of copper-based MOD ink (Cuf-AMP-OH ink) after heat treatment at 350 °C is 9.46 μΩ·cm, which is 5.5 times higher than the specific resistivity of bulk copper. A simple stamping transfer was conducted to demonstrate the potential of our ink for commercial printing processes.
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- 2014
14. Low-Temperature, Dry Transfer-Printing of a Patterned Graphene Monolayer
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Sugkyun Cha, Jin Hyoun Kang, Seojun Lee, Minjeong Cha, and Changsoon Kim
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Condensed Matter - Materials Science ,Multidisciplinary ,Materials science ,Graphene ,Graphene foam ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Nanotechnology ,Substrate (printing) ,Bioinformatics ,Article ,law.invention ,Polystyrene sulfonate ,chemistry.chemical_compound ,chemistry ,law ,Monolayer ,Dry transfer ,Layer (electronics) ,Graphene oxide paper - Abstract
Graphene has recently attracted much interest as a material for flexible, transparent electrodes or active layers in electronic and photonic devices. However, realization of such graphene-based devices is limited due to difficulties in obtaining patterned graphene monolayers on top of materials that are degraded when exposed to a high-temperature or wet process. We demonstrate a low-temperature, dry process capable of transfer-printing a patterned graphene monolayer grown on Cu foil onto a target substrate using an elastomeric stamp. A challenge in realizing this is to obtain a high-quality graphene layer on a hydrophobic stamp made of poly(dimethylsiloxane), which is overcome by introducing two crucial modifications to the conventional wet-transfer method – the use of a support layer composed of Au and the decrease in surface tension of the liquid bath. Using this technique, patterns of a graphene monolayer were transfer-printed on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and MoO3, both of which are easily degraded when exposed to an aqueous or aggressive patterning process. We discuss the range of application of this technique, which is currently limited by oligomer contaminants and possible means to expand it by eliminating the contamination problem.
- Published
- 2015
15. Chiromagnetic nanoparticles and gels.
- Author
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Jihyeon Yeom, Santos, Uallisson S., Chekini, Mahshid, Minjeong Cha, de Moura, André F., and Kotov, Nicholas A.
- Published
- 2018
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16. Multi-Functional Transparent Luminescent Configuration for Advanced Photovoltaics
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Young Rag Do, Il Ki Han, Minjeong Cha, Hyun Keun Kwon, S. Joon Kwon, Kyu-Tae Lee, Soon-Hong Kwon, Doo-Hyun Ko, Richard H. Friend, Minwoo Nam, Sangpil Park, Sung Hwan Lee, Hanju Rhee, Kyoungsik Kim, Joon Soo Han, Sangin Kim, and Dawoon Jeong
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Materials science ,Organic solar cell ,Renewable Energy, Sustainability and the Environment ,business.industry ,Photovoltaic system ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Nanoimprint lithography ,law.invention ,Modulation ,law ,Photovoltaics ,Solar cell ,Optoelectronics ,General Materials Science ,Photonics ,0210 nano-technology ,business ,Nanoscopic scale - Abstract
The conversion and manipulation of light via luminescent down-shifting (LDS) show promise in numerous applications. An elegant combination of lanthanide-doped polymer-derived ceramics incorporated with versatile nanopatterns is demonstrated using direct nanoimprint techniques. The prompt formation of nanoscale photonic structures enhances the fluorescence emission from the LDS while retaining the material's optical transparency. The functionality of this material is further expanded to accommodate surface energy modulation by nanopatterns. The practical applicability of this platform in photovoltaic devices is evaluated, showing distinctively enhanced efficiency and lifetime mainly attributed to the nanopattern assisted strong LDS property. Moreover, to efficiently combine two lanthanide emissions, so called a “double imprint” approach is devised by superpositioning two LDS nanopatterned arrays. Combined with the multi-functionality such as prominent LDS characteristics, color tunability, and surface energy modulation, the developed LDS platform offers promise for esthetic building-integrated photovoltaics.
- Published
- 2016
17. Higher Branched-Chain Amino Acid Intake Is Associated with Handgrip Strength among Korean Older Adults
- Author
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Seonghee Park, Minjeong Chae, Hyoungsu Park, and Kyong Park
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branched-chain amino acids ,leucine ,dietary intake ,older adults ,handgrip strength ,Nutrition. Foods and food supply ,TX341-641 - Abstract
Sarcopenia is a disease of old age characterized by decreased muscle mass and strength. Branched-chain amino acids (BCAAs) promote muscle mass synthesis and increase muscle strength. We aimed to develop a dietary amino acid database and to examine the association between BCAA intake and handgrip strength in Korean older adults. Data from the Korea National Health and Nutrition Examination Survey 2014–2018 were used. Overall, 4852 participants aged ≥65 years were included in the study. Demographic, lifestyle, and health data were obtained through interviews and questionnaires. The 24-h recall method was used to assess dietary intake. An amino acid database was established using the 9th revision of the Korean Standard Food Composition Table. The mean handgrip strength was estimated from triplicate measurements obtained using the dominant hand. Multivariable linear regression analysis was performed to assess the association between BCAA intake and handgrip strength. Grains greatly contributed to amino acid intake; however, a significant negative association was observed between handgrip strength and increased BCAA intake through grains. In the fully adjusted model, leucine intake and handgrip strength showed a positive association. Thus, consuming BCAAs (especially leucine) via a variety of food sources can help maintain muscle health in older people.
- Published
- 2021
- Full Text
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18. Estimation of Dietary Amino Acid Intake and Independent Correlates of Skeletal Muscle Mass Index among Korean Adults
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Minjeong Chae, Hyoungsu Park, and Kyong Park
- Subjects
amino acid ,dietary intake ,skeletal muscle mass ,Nutrition. Foods and food supply ,TX341-641 - Abstract
The aim of this study was to develop a database to identify dietary amino acid intake levels, and to determine whether any amino acid groups were independently correlated with skeletal muscle mass index (SMI). We used data from the Korea National Health and Nutrition Examination Survey 2008–2011, and a total of 3292 participants aged 50–64 years were included in the analysis. Dietary data were obtained using the 24 h recall method. Data regarding dietary amino acid intake was assessed using the computer-aided nutritional analysis program 4.0 published by the Korean Nutrition Society. Multivariate linear regression analysis was used to identify independent correlates of SMI. The major food group that contributed the highest essential amino acid intake was grain and grain products (histidine 25.5%, isoleucine 43.9%, leucine 44.2%, methionine 31.0%, phenylalanine 44.8%, tryptophan 26.4%, and valine 50.8%). Higher SMI was independently associated with sex (men), lower age and body mass index, higher levels of physical activity, and a higher intake of energy and branched-chain amino acids. These results are expected to be used as a basis for developing dietary amino acid intake guidelines for Koreans.
- Published
- 2020
- Full Text
- View/download PDF
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