Maluangnont, Tosapol

Preferred name

Alternative Name

Maluangnont, T.

Main Affiliation

Integrated Innovative Technology

tosapol.ma@kmitl.ac.th

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Titania nanosheet generates peroxynitrite-dependent S-nitrosylation and enhances p53 function in lung cancer cells
(2021-08-01)
Soonnarong, Rapeepun
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Tungsukruthai, Sucharat
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Nutho, Bodee
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Rungrotmongkol, Thanyada
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Vinayanuwattikun, Chanida
Metal nanomaterials can enhance the efficacy of current cancer therapies. Here, we show that Ti<inf>0.8</inf> O<inf>2</inf> nanosheets cause cytotoxicity in several lung cancer cells but not in normal cells. The nanosheet-treated cells showed certain apoptosis characteristics. Protein analysis further indicated the activation of the p53-dependent death mechanism. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses revealed the cellular uptake of the nanosheets and the induction of cell morphological change. The nanosheets also exhibited a substantial apoptosis effect on drug-resistant metastatic primary lung cancer cells, and it was found that the potency of the nanosheets was dramatically higher than standard drugs. Ti<inf>0.8</inf> O<inf>2</inf> nanosheets induce apoptosis through a molecular mechanism involving peroxynitrite (ONOO−) generation. As peroxynitrite is known to be a potent inducer of S-nitrosylation, we further found that the nanosheets mediated the S-nitrosylation of p53 at C182, resulting in higher protein-protein complex stability, and this was likely to induce the surrounding residues, located in the interface region, to bind more strongly to each other. Molecular dynamics analysis revealed that S-nitrosylation stabilized the p53 dimer with a ∆Gbindresidue of <−1.5 kcal/mol. These results provide novel insight on the apoptosis induction effect of the nanosheets via a molecular mechanism involving S-nitrosylation of the p53 protein, emphasizing the mechanism of action of nanomaterials for cancer therapy.
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The role of γ-C2H5NO2 as a new transient liquid phase in cold sintering process of BaTiO3 composites
(2024-07-01)
Noisak, Jitrawan
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Ieamviteevanich, Pimchanok
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Charoonsuk, Thitirat
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Pakawanit, Phakkhananan
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Pinpru, Nattapong
Dielectric materials, such as barium titanate (BT)-based materials, have excellent dielectric properties but require high temperatures (above 1300 °C) for ceramic fabrication, leading to high costs and energy loss. The cold sintering process (CSP) offers a solution to these issues and is gaining worldwide attention as an innovative fabrication route. In this work, we proposed an alternative organic ferroelectric phase, gamma-glycine (γ-GC), which acts as a transient liquid phase to fabricate high-density composites with barium titanate (BT) at low temperatures through CSP. Our findings show that the density of 15γ-GC/85BT reached 96.7%±1.6% when it was sintered at 120 °C for 6 h under 10 MPa uniaxial pressure. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) mappings of the composite suggested that γ-GC completely underwent the precipitation–dissolution process and, therefore, filled between BT particles. Moreover, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the preservation of γ-GC without undesired phase transformation. In addition, the ferroelectric and dielectric properties of γ-GC/BT composites have been reported. The high dielectric constant (ε<inf>r</inf>) was 3600, and the low dielectric loss (tanδ) was 1.20 at 200 °C and 100 kHz for the 15γ-GC/85BT composite. The hysteresis loop showed a remanent polarization (P<inf>r</inf>) of 0.55 µC·cm-2 and a coercive field (E<inf>c</inf>) of 7.25 kV·cm-1. Our findings reaffirmed that an organic ferroelectric material (γ-GC) can act as a transient liquid phase in a CSP that can successfully and sustainably fabricate γ-GC/BT composites at low temperatures while delivering outstandingly high performance.
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Production of liquid fuel from palmitic acid over nanocrystalline CeO2-based catalysts with minimal use of H2
(2017-01-01)
Maluangnont, Tosapol
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Dararat, Chalinee
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Kulrat, Teerapong
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Soontontaweesub, Surachet
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Anothaiwalaikul, Thitima
The deoxygenation of palmitic acid into diesel-range hydrocarbons can be promoted over nanocrystalline ceria-based catalysts under atmospheric N<inf>2</inf> or 10% H<inf>2</inf>/N<inf>2</inf> in a fixed-bed flow reactor at 400 °C. Oxygen vacancy sites are active for ketonization of palmitic acid to C<inf>31</inf> ketone and also subsequent cracking of the formed ketone to hydrocarbons. The 22–31% selectivity of C<inf>9</inf> to C<inf>17</inf> liquid hydrocarbons can be achieved at 100% palmitic acid conversion. The deoxygenation under N<inf>2</inf> can be facilitated, presumably by hydrogen transfer from coke precursors. Catalytic activity of ceria-based catalysts can be tuned by pretreatment conditions, type of a carrier gas, or lattice modification.
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Local structure of stoichiometric and oxygen-deficient A 2Ti6O13 (A = Li, Na, and K) studied by X-ray absorption spectroscopy and first-principles calculations
(2018-10-21)
Kanchanawarin, Jarin
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Limphirat, Wanwisa
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Promchana, Pratya
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Sooknoi, Tawan
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Maluangnont, Tosapol
Oxygen vacancy defects (V<inf>O</inf>) in Ti-based oxides play important roles in catalytic processes despite limited knowledge regarding their formation and characterization. Here, we demonstrate the use of X-ray absorption spectroscopy (XAS) measurements to compare the relative proportion of V<inf>O</inf> defects in as-grown alkali hexatitanate A<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf> (A = Li, Na, K). Both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) regions were studied. The similarity of measured XANES spectra of Ti K-edge in all samples indicates the presence of (Ti4+)O<inf>6</inf> units in good agreement with reported X-ray diffraction results. The small influence of cations A at the tunnel was observed and can be well reproduced in the simulated spectra. In addition, we present a semi-quantitative approach to intuitively determine the content of V<inf>O</inf> defects in oxygen-deficient K<inf>2</inf>Ti<inf>6</inf>O<inf>13-x</inf> by in situ time-resolved XAS measurements under reducing conditions (10%H<inf>2</inf>/Ar, 50-650 °C). The in situ XANES measurements indicate that the oxidation state of bulk Ti remains the same as the as-grown sample, i.e., 4+, at elevated temperatures. By in situ EXAFS measurements, the relative number of V<inf>O</inf> defects is highest at a reduction temperature of ∼550 °C and slightly decreases after that. To confirm the formation of V<inf>O</inf> defects, first-principles calculations were independently carried out using a 126-atom K<inf>2</inf>Ti<inf>6</inf>O<inf>13</inf> supercell with V<inf>O</inf> at various positions. Based on calculated EXAFS, the removal of the oxygen atom nearest to the tunnel, which is the lowest energy structure, provides a good match to the experimental spectra.
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Enabling enhanced lithium storage capacity of two-dimensional pentagonal BN2 by aluminum doping
(2023-04-21)
Thanasarnsurapong, Thanasee
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Detrattanawichai, Panyalak
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Dabsamut, Klichchupong
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Simalaotao, Kodchakorn
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Maluangnont, Tosapol
Researchers studying Li-ion batteries (LIBs) have become very interested in two-dimensional (2D) materials possessing an unusual pentagonal atomic structure. Recently, penta-graphene, penta-B<inf>2</inf>C, and penta-BN<inf>2</inf> have been theoretically described. These materials are attractive for use as state-of-the-art anodes in LIBs due to their high storage capacities of 1489, 1594, and 2071 mA h g−1, respectively. Here, we propose enhancing storage capacity by introducing defect doping. For example, one Al atom was incorporated into 2 × 2 penta-BN<inf>2</inf>, corresponding to AlB<inf>7</inf>N<inf>16</inf>. The energy calculated for the adsorption of a single Li atom onto the Al-doped material is more favorable than that for the Al-free analog, indicating that doping can strengthen an affinity for Li. The Al-doped penta-BN<inf>2</inf> exhibits metallic conductivity during Li adsorption. In the layer-by-layer Li adsorption, doping a single Al atom into 2 × 2 penta-BN<inf>2</inf> has an 11% higher storage capacity (2297 mA h g−1) than penta-BN<inf>2</inf> despite having a slightly heavier formula weight. The Al-doped penta-BN<inf>2</inf> displays a low open-circuit voltage of 0.48 V. Substituting aluminum for boron enhances the Li adsorption capacity of penta-BN<inf>2</inf>, and the computed storage capacity is presently one of the highest published values for pentagonal materials.
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FABRICATION OF BA5NB4O15 CERAMICS BY FLUX-ASSISTED ULTRA-LOW SINTERING TEMPERATURE TECHNIQUE
(2025-01-01)
Pulphol, Phieraya
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Teandam, Apichayaporn
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Charoonsuk, Thitirat
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Vittayakorn, Wanwilai
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Maluangnont, Tosapol
Ba<inf>5</inf>Nb<inf>4</inf>O<inf>15</inf> ceramic is a promising dielectric material for microwave frequencies. One of the factors that affects its dielectric properties is density, which can be controlled by fabrication processes such as sintering. Normally, conventional sintering requires high sintering temperature (T?> 1,200ºC) to produce grain coarsening and pore reduction which consumes high energy. However, there has been growing interest in low-temperature ceramic processing due to its potential to revolutionize the way ceramic materials are manufactured. Cold sintering is a new sintering technique that can be used to fabricate dense ceramics below 300°C. It can be applied to a variety of compounds, and the densification process is driven by the dissolution-precipitation mechanism, with the aid of a congruent solvent, pressure, and temperature. Herein, Ba<inf>5</inf>Nb<inf>4</inf>O<inf>15</inf> ceramics are prepared by cold sintering technique using hydrated barium hydroxide (Ba(OH)<inf>2</inf>-8H<inf>2</inf>O) as a flux to reduce sintering temperature and introduce densification process. The effects of processing parameters, including sintering temperature, dwelling time, pressure, and flux concentration, on the density and dielectric properties of sintered samples were investigated. Phase formation and electrical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and an LCR meter. Under the sintering conditions T = 150°C, pressure = 7,000 kPa, and t = 60 min, the obtained Ba<inf>5</inf>Nb<inf>4</inf>O<inf>15</inf> ceramic exhibited a relative density of ˜80% which closes to the ceramics obtained from conventional sintering. These results suggest that sintering temperature has little influence on sample density, while applied pressure is the dominant factor in improving density. The mechanism of flux-assisted cold sintering and dielectric properties are also discussed.
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Composition–structure mapping of fluorine–graphite intercalation compounds
(2026-07-01)
Maluangnont, Tosapol
Fluorine–graphite intercalation compounds (FGICs) have been extensively studied for their enhanced conductivity, yet their reported composition–structure relationships remain scattered. Here, we present an empirical analysis of FGICs focusing on interlayer spacing dᵢ, carbon-to-fluorine ratio C/F, and stage number s, compiling literature data spanning multiple decades. Variations to graphite host (including highly oriented pyrolytic graphite, natural graphite, powder, fiber, mesophase pitch, microbead, and specialized carbon sources) and synthetic methods are also considered. Despite substantial variability in experimental protocols, the data (184 entries) collapse into three regimes across stages 1–4 with C/F ∼0.63–16.7 (71.5−8.6 wt%F). The dᵢ ∼4.4, ∼6.0, and ∼11.4 Å regimes have been interpreted in the literature as corresponding to fluorine nesting, semi-ionic fluorine intercalation, and graphite bi-intercalation structures, respectively. Other smaller subsets are also identified at dᵢ ∼5.5 Å (coexistence of planar sp2 C=C/puckered sp3 C−F), 6.0 Å (covalent C−F), and 7.8 Å (F<inf>2</inf> perpendicular to graphene sheets). This diversity reflects the anisotropic mechanical response of graphite: stiffness along the stacking direction constrains expansion, while in-plane softness accommodates compositional variation. We introduce V<inf>gal</inf> representing the available gallery volume (i.e., at the interlayer space) per carbon atom which does not require assumptions about fluorine size. This descriptor preserves such three regimes, whereas the traditional packing fraction varies widely and may exceed physically meaningful limits. Taken together, this work provides an interpretative classification of FGICs, consolidating insights into fluorine intercalation that are not evident from individual reports while helping place future FGICs within, and potentially extend, the known composition–structure landscape.
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Structural and Compositional Characteristics of Ball-Milled Lepidocrocite Alkali Titanate and the Correlation to Its Surface Acidic-Basic Properties
(2021-11-01)
Maluangnont, Tosapol
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Chanlek, Narong
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Khamman, Orawan
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Vittayakorn, Wanwilai
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Sooknoi, Tawan
The studies on mechanical treatments of layered alkali metal oxides are limited despite their diverse compositions/structures and potential for property tuning. In this work, we vibratory mill Cs0.7Zn0.35Ti1.65O4, K0.8Zn0.4Ti1.6O4, and Cs2Ti6O13 for up to 4 h, during which the lepidocrocite-type structure and the plate-like morphology are well preserved. X-ray diffraction (XRD) indicates a tiny (≤0.6 Å) interlayer expansion accompanied by the enhancement of the preferred orientation along the stacking direction. Chemical analyses across multiple length scales suggest Cs deintercalation, elemental redistributions, and bulk-to-surface (or crystal edge) Cs migration. This ball-milling-induced Cs-rich moiety partially blocks the surface acid sites, although the solids still show a dominating acidic character. The ball-milled samples Cs0.7-pZn0.35-qTi1.65O4-δ contain vacancies between the sheets (p) and at the sheets (q and δ). It is deduced from Sanderson's electronegativity equalization principle and experimentally verified by X-ray photoelectron spectroscopy (XPS) that ball milling increases (decreases) the partial charge at the surface acidic Ti4+/Zn2+ (basic O2-) sites. These nonporous solids (≤20 m2·g-1) contain water sorbed on the external surface as high as 1.1 mol·mol-1, which is comparable to that in a water-intercalated sample. Our work expands the current understanding of the reactivity vs robustness in layered alkali titanates under physically demanding conditions, complementing knowledge gathered via the soft chemistry approach.
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Point Defects in Rare-Earth Perovskite Systems BaMO3 (M = Ce, Pr and Tb) on Dielectric and Magnetic Behaviors
(2023-01-01)
Pulphol, Phieraya
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Tariwong, Yaowaluk
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Charoonsuk, Thitirat
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Maluangnont, Tosapol
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Vittayakorn, Wanwilai
This study focused on the rare-earth hetero-valent substituted perovskite BaMO<inf>3</inf> (M = Ce, Pr and Tb) which expected to show magnetoelectric response. In general, diamagnetic feature is presented in the 4f 0 BaCeO<inf>3</inf> system down to 2 K which is chosen as a reference in the study while BaPrO<inf>3</inf> (4f 1) and BaTbO<inf>3</inf> (4f 7) display antiferromagnetic phase transition at T<inf>N</inf> = 11.7 and 33.2 K, respectively, measured by MPMS magnetometer. At high oxygen partial pressure and donor ion-substitution (Nb5+), the BaMO<inf>3</inf> systems demonstrate a similar defect chemistry to titanate perovskite which compensated by Ba-vacancy. Dielectric relaxation is detected for the doublet (BaPrO<inf>3</inf> and BaTbO<inf>3</inf>) at the antiferromagnetic phase transition region. In order to examine the magnetoelectric response, the 8 Tesla of magnetic field is applied to the samples during the dielectric measurement. BaTbO<inf>3</inf> shows a modest magnetoelectric response around 0.2% at the antiferromagnetic phase transition while that of BaPrO<inf>3</inf> is silent. The activation energies derived from Arrhenius equation are reported to be in the range of 0.2 − 0.6 eV.
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Sodium-Poor, Hydroxyl-Rich, Defective Na2Ti3O7 Prepared by γ-Irradiation and Its Enhanced Proton Conductivity
(2024-09-30)
Maluangnont, Tosapol
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Sangtawesin, Tanagorn
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Pulphol, Phieraya
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Khamman, Orawan
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Reunchan, Pakpoom
The use of γ-irradiation to tailor the physicochemical properties of materials is not widely applied to layered alkali metal oxides. Herein, we show that γ-irradiation (up to 400 kGy) of Na<inf>2</inf>Ti<inf>3</inf>O<inf>7</inf> leads to a sodium-poor, hydroxyl-rich analogue where the layered structure, plate-like morphology, and textural properties are preserved. The deintercalation of sodium ions modifies the Ti-O bond lengths and expands the unit cell; the latter is supported by density functional theory (DFT) calculations. 23Na solid-state NMR suggests the transport of the symmetric, 7-fold Na2 sites to an intermediate environment, which is closer to the asymmetric, 9-fold Na1 sites. An 8 wt % mass loss (1.4 mol water/mol titanate) is observed, indicating an increased concentration of protons/hydroxyls. These hydroxyl groups (i.e., lattice protons) possess higher thermal stability than solely surface-adsorbed ones in the nonirradiated sample. At 200-400 kGy, the proton conduction (50 °C and ∼70% RH) of ∼10-6 S·cm-1 is 1 order of magnitude larger than that in the nonirradiated sample; the relaxation time decreases from 30 to 2-6 μs with γ-irradiation. The γ-dose dependence of dielectric loss is also present and analyzed using the Jonscher universal power law, indicating the low-frequency dispersion behavior characteristics of high charge densities.

Maluangnont, Tosapol

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