Publications by authors named "Kyusik Yun"

Next-generation 2D materials, such as transition metal carbides and nitrides (MXenes), have received increasing attention owing to their physicochemical properties. In this study, we synthesized highly intense fluorescent materials, nitrogen-doped MXene quantum dots (N-MQDs) using an easy and less time-consuming microwave-assisted method. These N-MQDs are spherical, fluorescent, and highly sensitive materials, as confirmed by high-resolution transmission electron microscopy, atomic force microscopy, UV-visible, fluorescence, Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, zeta potential, and contact angle measurements.

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An zoonotic viral infection called monkeypox (MPXV) is the leading infectious disease globally. MPXV can easily spread from human to human through direct and indirect sexual contact; therefore, accurate and early detection of MPXV is crucial for reducing mortality. Fluorescence-based materials have received significant attention in recent years for biomedical applications.

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Quantum dots (QDs), a novel category of semiconductor materials, exhibit extraordinary capabilities in tuning optical characteristics. Their emergence in biophotonics has been noteworthy, particularly in bio-imaging, biosensing, and theranostics applications. Although conventional QDs such as PbS, CdSe, CdS, and HgTe have garnered attention for their promising features, the presence of heavy metals in these QDs poses significant challenges for biological use.

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Monkeypox is a zoonotic viral infection caused by the monkeypox virus (MPXV), which belongs to the Poxviridae family of the Orthopoxvirus (OPXV) genus. Monkeypox is transmitted from animals to humans and humans to humans; therefore, the accurate and early detection of MPXV is crucial for reducing mortality. A novel graphene-based material, graphene quantum rods (GQRs) was synthesized and confirmed using high-resolution transmission electron microscopy (HR-TEM) and atomic force microscopy (AFM).

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Neurotransmitters (NTs) are endogenous low-molecular-weight chemical compounds that transmit synaptic signals in the central nervous system. These NTs play a crucial role in facilitating signal communication, motor control, and processes related to memory and learning. Abnormalities in the levels of NTs lead to chronic mental health disorders and heart diseases.

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Article Synopsis
  • The development of green fuel from water splitting is crucial for future generations, but the scarcity of fresh water poses a significant challenge.
  • Current electrolyzer techniques cannot directly use seawater due to corrosion issues and the need for single atom catalysts has historically involved harsh chemical processes.
  • A new cobalt-based electrocatalyst, synthesized from waste orange peel, demonstrates high efficiency in oxygen evolution reactions and can successfully operate in desalinated seawater, showing 15 times more activity than commercial counterparts.
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Nanomaterials (NMs) synthesized from natural sources have been attracting greater attention, due to their intrinsic advantages including biocompatibility, stimuli-responsive property, nontoxicity, cost-effectiveness, and non-immunogenic characteristics in the biological environment. Among various biomedical applications, a breakthrough has been achieved in the development of drug delivery systems (DDS). Biocompatibility is necessary for treating a disease safely without any adverse effects.

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Mesenchymal stem cells (MSCs) repair tissue injury by upregulating the paracrine secretion of cytokines and growth factors. Human MSC has been recognized as a promising therapeutic material for treatment of various human diseases. Even though the effect of epidermal growth factor (EGF) has been well investigated, the synergetic effect of EGF and MSC has not been studied.

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Gel polymer electrolytes (GPEs) hold tremendous potential for advancing high-energy-density and safe rechargeable solid-state batteries, making them a transformative technology for advancing electric vehicles. GPEs offer high ionic conductivity and mechanical stability, enabling their use in quasi-solid-state batteries that combine solid-state interfaces with liquid-like behavior. Various GPEs based on different materials, including flame-retardant GPEs, dendrite-free polymer gel electrolytes, hybrid solid-state batteries, and 3D printable GPEs, have been developed.

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Article Synopsis
  • Pollution by heavy metals (HMs) is a major global concern driven primarily by industrialization and urbanization, negatively impacting the health of all living organisms.
  • Two conventional methods for reducing HMs—physical and chemical—are costly and inefficient, leading researchers to explore more sustainable alternatives like phytoremediation, which uses hyper-accumulator plants to clean up contaminated environments.
  • This review highlights the different types of phytoremediation, the effectiveness of Arabidopsis thaliana in accumulating HMs, and discusses the potential of genome editing technologies to enhance the phytoremediation process for environmental conservation.
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Pollution by microplastics (MPs) formed by the physicochemical breakdown of plastics are a worldwide issue with long-lasting and hazardous natural effects. The natural expulsion of MPs takes several years and can be dangerous. Several effective technological innovations have been developed over the years to remediate harmful MPs.

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A label-free biosensor is described based on the Raman spectroscopic signatures of monolayer graphene, which are modified in the compartment of cancer cells because of electron-phonon coupling in monolayer graphene. Specifically, the Raman spectra of electrostatically gated monolayer graphene on SiO/Si substrates, in the voltage range from 0 to 5 V, were studied in the absence and the presence of cancer cells. Density functional theory simulations afforded a correlation between cancer cells and the observed Raman spectra, through the regulation of the intensities of the G and 2D Raman vibrational modes with applied voltage.

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A simple, cost-effective system was developed for dopamine (DA) detection using green synthesized 1-6 ​nm honey-based carbon quantum dots (H-CQDs) exhibiting bluish green fluorescence. The H-CQDs exhibited emission at 445 ​nm, with a quantum yield of ∼44%. The H-CQDs were used as a probe for electron transfer based DA detection and changes in H-CQD color in the presence of DA.

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As the second wave of COVID-19 hits South Asia, an increasing deadly complication 'fungal infections (such as Mycosis, Candida and Aspergillus) outbreak' has been raised concern about the insufficient technologies and medicals for its diagnosis and therapy. Biosilica based nano-therapy can be used for therapeutic efficacy, yet their direct role as antibiotic agent with biocompatibility and stability remains unclear. Here, we report that a diatomaceous earth (DE) framework semiconductor composite conjugated DE and in-house synthesized zinc oxide (DE-ZnO), as an antibiotic agent for the enhancement of antibiotic efficacy and persistence.

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To materialize the excellent photocatalyst for crystal violet dye-degradation, the graphitic carbon-encapsulated vanadium pentoxide (GC-VO) nanocomposites were synthesized through the simple sonication method by using the green tea waste-derived GC nanoflakes and the sonochemically synthesized VO nanorods. The nanocomposites were confirmed to comprise an aggregated morphology, in which the orthorhombic VO nanorods were well anchored with the intertwingled GC nanoflakes. Owing to the encapsulation of defective VO by conductive GC, the GC-VO nanocomposites exhibited the enhanced photocatalytic dye-degradation efficiency up to 98.

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The two-dimensional carbonaceous nanocomposites tend to have extreme capacitance and catalysis activity because of their surface tunability of oxygenated moieties aiding in photocatalytic degradation. Herewith, we performed microwave-assisted alkaline treatment of graphene oxide sheets to attain defective sites on the graphitic surface by altering microwave parameters. The synergism of zinc oxide (ZnO) on the graphitic surface impacts electronic transitions paving paths for vacant oxygen sites to promote photocatalytic degradation and catalytic activity.

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Carbon quantum dots (CQDs) synthesized from biological sources play a significant role in biomedical and environmental applications, including bioimaging, biosensing, metal ions detection and electrocatalytic oxidations. Herein, we synthesized blue-emitting carbon quantum dots using maple tree leaves via a one-step hydrothermal process to detect Cesium ions selectively. The synthesized CQDs' functional group composition, morphology, and pH stability was analytical and morphologically investigated.

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Facile and modest synthesis of significantly effective and less-cost catalysts for environmental pollutant degradation and oxygen evolution holds substantial potential in environmental and energy fields. Hereby, Trimetallic organic frameworks (TriMOF) consisting of Fe, Co, and Zn synergized on the surface of activated carbon (AC) from pineapple leaves tend to show exponential catalytic activity due to the more excellent ionic conductivity, catalytic stability and multiple active sites provided by different metal precursors. Furthermore, the developed nanocomposite was coated on the stainless-steel electrode substrate at room temperature, delivering greater electrocatalytic surface area and numerous active sites.

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The synthesis of BiWO and CeO photocatalytic nanomaterials exhibit a great ability to photodegrade the antibiotics and shown excellent oxidation of various organic pollutants. Heterostructure 1:1 & 2:1 BiWO/CeO nanocomposite was successfully synthesized via the facile sono-dispersion method and exquisite photocatalytic activity. The 0.

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An emerging global necessity for alternative resources combined with maximum catalytic efficiency, low cost, and eco-friendly composite remains a hotspot in the scientific society. Hereby, a novel protocol is approached to design a heterostructure of Zinc MOF decorated on the surface of 2D activated carbon (AC) through a simplistic approach. To begin with, analytical, morphological and spectroscopical studies were performed to identify the functional moieties, cruciate-flower like morphology and oxidative state of atoms present in the composite Zn-MOF @AC.

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The hydrothermal preparation of o-dianisidine and triazine interlinked porous organic polymer and its successive derivatisation via metal infusion (Ni, Cu) under hydrothermal and calcination conditions (700 °C) to yield pristine (ANIPOP-700) and Ni/Cu decorated porous carbon are described here (Ni-ANIPOP-700 and Cu-ANIPOP-700). To confirm their chemical and morphological properties, the as-prepared materials were methodically analyzed using solid state C and N NMR, X-ray diffraction, Raman spectroscopy, field emission scanning and high resolution transmission electron microscopic techniques, and x-ray photoelectron spectroscopy. Furthermore, the electrocatalytic activities of these electrocatalysts were thoroughly investigated under standard oxygen evolution (OER) and hydrogen evolution reaction (HER) conditions.

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This report details the preparation, characterization, and applications of an inexpensive adsorbent obtained from Azadirachta indica leaves (Neem biochar (NBC)) and used to remove Cr(VI) from the synthetic waste water. The obtained NBC was characterized by XRD, FTIR, FESEM, EDX and Zeta potential measurements. Adsorption experiments conducted at various pH levels confirmed that 58.

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Heterostructured transition metal oxide hybrid have more attention in energy saving and environmental related field due to their higher electro-catalytic activity. In this work, we demonstrated SnO decorated with NiO nanocrystal electrocatalyst is successfully synthesized through solvothermal method and well characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction and X-ray photoelectron spectroscopy. Physical characterizations confirm that spherical shape of SnO nanoparticles are homogeneously dispersed on the surface of NiO.

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Demonstrating a highly efficient non-noble bifunctional catalyst for complete water electrolysis remains challenging because of kinetic limitations and crucial importance for future energy harvesting. Herein, a low-cost, integrated composite of a Ni-Co metal-organic framework decorated with thin MoS nanosheets was synthesized by a simple hydrothermal method followed by carbonization and phosphorization for electrochemical oxygen and hydrogen evolution reactions. Such a composite heterostructure exhibits outstanding performance in the electrocatalysis process with a lower overpotential of 184 mV for the oxygen evolution reaction (OER) and 84 mV for the hydrogen evolution reaction (HER) in 1.

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