Publications by authors named "H Y Lee"

58,066 Publications

Organic cultivation practices enhanced antioxidant activities and secondary metabolites in giant granadilla (Passiflora quadrangularis L.).

PLoS One 2021 26;16(7):e0255059. Epub 2021 Jul 26.

Department of Biology, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor Darul Ehsan, Malaysia.

Passiflora quadrangularis L. belongs to the family Passifloraceae which bears larger fruit with edible juicy mesocarp and pulp known as a good source of phytochemicals. Cultivation and plant management practices are known to influence the phytochemical compositions of agricultural produce. This study aimed to examine the influence of the cultivation practices on the antioxidant activities and secondary metabolites of the organically and conventionally grown P. quadrangularis. Findings revealed organically treated P. quadrangularis plants showed enhancement in their antioxidant properties and secondary metabolites profiles. Among the plant parts, leaves of P. quadrangularis grown organically possessed higher antioxidant activities compared to the conventional in all assays evaluated. The antioxidant activities in the edible parts of the P. quadrangularis fruit have also been enhanced through organic cultivation with significantly higher total phenolic content and DPPH in mesocarp, and the pulp showed higher total flavonoid content, DPPH and FRAP. This observation is supported by a higher level of vitamins and secondary metabolites in the samples. The secondary metabolites profile showed mesocarps were phenolic rich, the pulps were flavonoids rich while leaves showed good composition of phenolics, flavonoids and terpenoids with outstanding antioxidant activities. The common secondary metabolites for organically produced P. quadrangularis in different plant parts include 2-isopropyl-3-methoxycinnamic acid (mesocarp and pulp), myricetin isomers (pulp and leaves), and malvidin-3-O-arabinoside isomers (pulp and leaves). This study confirmed that organic cultivated P. quadrangularis possessed higher antioxidant activities contributed by its vitamins and secondary metabolites.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0255059PLOS
July 2021

Unveiling the Origin of Robust Ferroelectricity in Sub-2 nm Hafnium Zirconium Oxide Films.

ACS Appl Mater Interfaces 2021 Jul 26. Epub 2021 Jul 26.

School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.

HfO-based ferroelectrics are highly expected to lead the new paradigm of nanoelectronic devices owing to their unexpected ability to enhance ferroelectricity in the ultimate thickness scaling limit (≤2 nm). However, an understanding of its physical origin remains uncertain because its direct microstructural and chemical characterization in such a thickness regime is extremely challenging. Herein, we solve the mystery for the continuous retention of high ferroelectricity in an ultrathin hafnium zirconium oxide (HZO) film (∼2 nm) by unveiling the evolution of microstructures and crystallographic orientations using a combination of state-of-the-art structural analysis techniques beyond analytical limits and theoretical approaches. We demonstrate that the enhancement of ferroelectricity in ultrathin HZO films originates from textured grains with a preferred orientation along an unusual out-of-plane direction of (112). In principle, (112)-oriented grains can exhibit 62% greater net polarization than the randomly oriented grains observed in thicker samples (>4 nm). Our first-principles calculations prove that the hydroxyl adsorption during the deposition process can significantly reduce the surface energy of (112)-oriented films, thereby stabilizing the high-index facet of (112). This work provides new insights into the ultimate scaling of HfO-based ferroelectrics, which may facilitate the design of future extremely small-scale logic and memory devices.
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http://dx.doi.org/10.1021/acsami.1c08718DOI Listing
July 2021

Morphology Transformation of Foldamer Assemblies Triggered by Single Oxygen Atom on Critical Residue Switch.

Small 2021 Jul 26:e2102525. Epub 2021 Jul 26.

Center for Multiscale Chiral Architectures, Department of Chemistry, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, 34141, Korea.

The synthesis of morphologically well-defined peptidic materials via self-assembly is challenging but demanding for biocompatible functional materials. Moreover, switching morphology from a given shape to other predictable forms by molecular modification of the identical building block is an even more complicated subject because the self-assembly of flexible peptides is prone to diverge upon subtle structural change. To accomplish controllable morphology transformation, systematic self-assembly studies are performed using congener short β-peptide foldamers to find a minimal structural change that alters the self-assembled morphology. Introduction of oxygen-containing β-amino acid (ATFC) for subtle electronic perturbation on hydrophobic foldamer induces a previously inaccessible solid-state conformational split to generate the most susceptible modification site for morphology transformation of the foldamer assemblies. The site-dependent morphological switching power of ATFC is further demonstrated by dual substitution experiments and proven by crystallographic analyses. Stepwise morphology transformation is shown by modifying an identical foldamer scaffold. This study will guide in designing peptidic molecules from scratch to create complex and biofunctional assemblies with nonspherical shapes.
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http://dx.doi.org/10.1002/smll.202102525DOI Listing
July 2021

Modelling of gene loss propensity in the pangenomes of three Brassica species suggests different mechanisms between polyploids and diploids.

Plant Biotechnol J 2021 Jul 26. Epub 2021 Jul 26.

School of Biological Sciences and the Institute of Agriculture, Faculty of Science, The University of Western Australia, Crawley, WA, Australia.

Plant genomes demonstrate significant presence/absence variation (PAV) within a species, however the factors that lead to this variation have not been studied systematically in Brassica across diploids and polyploids. Here, we developed pangenomes of polyploid Brassica napus and its two diploid progenitor genomes B. rapa and B. oleracea to infer how PAV may differ between diploids and polyploids. Modelling of gene loss suggests that loss propensity is primarily associated with transposable elements in the diploids while in B. napus, gene loss propensity is associated with homoeologous recombination. We use these results to gain insights into the different causes of gene loss, both in diploids and following polyploidisation, and pave the way for the application of machine learning methods to understanding the underlying biological and physical causes of gene presence/absence.
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http://dx.doi.org/10.1111/pbi.13674DOI Listing
July 2021

Self-Assembling Peptidic Bolaamphiphiles for Biomimetic Applications.

ACS Biomater Sci Eng 2021 Jul 26. Epub 2021 Jul 26.

Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.

Bolaamphiphile, which is a class of amphiphilic molecules, has a unique structure of two hydrophilic head groups at the ends of the hydrophobic center. Peptidic bolaamphiphiles that employ peptides or amino acids as their hydrophilic groups exhibit unique biochemical activities when they self-organize into supramolecular structures, which are not observed in a single molecule. The self-assembled peptidic bolaamphiphiles hold considerable promise for imitating proteins with biochemical activities, such as specific affinity toward heterogeneous substances, a catalytic activity similar to a metalloenzyme, physicochemical activity from harmonized amino acid segments, and the capability to encapsulate genes like a viral vector. These diverse activities give rise to large research interest in biomaterials engineering, along with the synthesis and characterization of the assembled structures. This review aims to address the recent progress in the applications of peptidic bolaamphiphile assemblies whose densely packed peptide motifs on their surface and their stacked hydrophobic centers exhibit unique protein-like activity and designer functionality, respectively.
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http://dx.doi.org/10.1021/acsbiomaterials.1c00576DOI Listing
July 2021
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