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1.
Anal Bioanal Chem ; 416(13): 3173-3183, 2024 May.
Article in English | MEDLINE | ID: mdl-38568232

ABSTRACT

A certified reference material (CRM, KRISS 108-01-002) for zearalenone in corn flour was developed to assure reliable and accurate measurements in testing laboratories. Commercially available corn flour underwent freeze-drying, pulverization, sieving, and homogenization. The final product was packed in amber bottles, approximately 14 g per unit, and preserved at -70 °C. 13C18-Zearalenone was used as an internal standard (IS) for the certification of zearalenone by isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC‒MS/MS) and for the analysis of α-zearalenol, ß-zearalenol, and zearalanone by LC‒MS/MS. The prepared CRM was sufficiently homogeneous, as the among-unit relative standard deviation for each mycotoxin ranged from 2.2 to 5.7 %. Additionally, the stability of the mycotoxins in the CRM was evaluated under different temperature conditions and scheduled test periods, including storage at -70°C, -20°C, and 4°C and room temperature for up to 12 months, 6 months, and 1 month, respectively. The content of each target mycotoxin in the CRM remained stable throughout the monitoring period at each temperature. Zearalenone content (153.6 ± 8.0 µg/kg) was assigned as the certified value. Meanwhile, the contents of α-zearalenol (1.30 ± 0.17 µg/kg), ß-zearalenol (4.75 ± 0.33 µg/kg), and zearalanone (2.09 ± 0.16 µg/kg) were provided as informative values.


Subject(s)
Flour , Reference Standards , Tandem Mass Spectrometry , Zea mays , Zearalenone , Zearalenone/analysis , Zea mays/chemistry , Flour/analysis , Flour/standards , Tandem Mass Spectrometry/methods , Chromatography, Liquid/methods , Limit of Detection , Food Contamination/analysis , Reproducibility of Results
2.
Nutrients ; 16(7)2024 Mar 27.
Article in English | MEDLINE | ID: mdl-38612999

ABSTRACT

Atractylodes macrocephala Koidz (AMK) is a traditional herbal medicine used for thousands of years in East Asia to improve a variety of illnesses and conditions, including cancers. This study explored the effect of AMK extract on apoptosis and tumor-grafted mice using AGS human gastric adenocarcinoma cells. We investigated the compounds, target genes, and associated diseases of AMK using the Traditional Chinese Medical Systems Pharmacy (TCMSP) database platform. Cell viability assay, cell cycle and mitochondrial depolarization analysis, caspase activity assay, reactive oxygen species (ROS) assay, and wound healing and spheroid formation assay were used to investigate the anti-cancer effects of AMK extract on AGS cells. Also, in vivo studies were conducted using subcutaneous xenografts. AMK extract reduced the viability of AGS cells and increased the sub-G1 cell fraction and the mitochondrial membrane potential. Also, AMK extract increased the production of ROS. AMK extract induced the increased caspase activities and modulated the mitogen-activated protein kinases (MAPK). In addition, AMK extract effectively inhibited AGS cell migration and led to a notable reduction in the growth of AGS spheroids. Moreover, AMK extract hindered the growth of AGS xenograft tumors in NSG mice. Our results suggest that AMK has anti-cancer effects by promoting cell cycle arrest and inhibiting the proliferation of AGS cancer cells and a xenograft model through apoptosis. This study could provide a novel approach to treat gastric cancer.


Subject(s)
Atractylodes , Stomach Neoplasms , Humans , Animals , Mice , Stomach Neoplasms/drug therapy , Reactive Oxygen Species , Caspases , Plant Extracts/pharmacology
3.
Micromachines (Basel) ; 15(3)2024 Feb 25.
Article in English | MEDLINE | ID: mdl-38542567

ABSTRACT

This research focuses on the manufacturing of a glass interposer that has gone through glass via (TGV) connection holes. Glass has unique properties that make it suitable for 3D integrated circuit (IC) interposers, which include low permittivity, high transparency, and adjustable thermal expansion coefficient. To date, various studies have suggested numerous techniques to generate holes in glass. In this study, we adopt the selective laser etching (SLE) technique. SLE consists of two processes: local modification via an ultrashort pulsed laser and chemical etching. In our previous study, we found that the process speed can be enhanced by changing the local modification method. For further enhancement in the process speed, in this study, we focus on the chemical etching process. In particular, we try to find a proper etchant for TGV formation. Here, four different etchants (HF, KOH, NaOH, and NH4F) are compared in order to improve the etching speed. For a quantitative comparison, we adopt the concept of selectivity. The results show that NH4F has the highest selectivity; therefore, we can tentatively claim that it is a promising candidate etchant for generating TGV. In addition, we also observe a taper angle variation according to the etchant used. The results show that the taper angle of the hole is dependent on the concentration of the etchant as well as the etchant itself. These results may be applicable to various industrial fields that aim to adjust the taper angle of holes.

4.
Adv Sci (Weinh) ; 11(10): e2304702, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38145969

ABSTRACT

The DNA damage response is essential for preserving genome integrity and eliminating damaged cells. Although cellular metabolism plays a central role in cell fate decision between proliferation, survival, or death, the metabolic response to DNA damage remains largely obscure. Here, this work shows that DNA damage induces fatty acid oxidation (FAO), which is required for DNA damage-induced cell death. Mechanistically, FAO induction increases cellular acetyl-CoA levels and promotes N-alpha-acetylation of caspase-2, leading to cell death. Whereas chemotherapy increases FAO related genes through peroxisome proliferator-activated receptor α (PPARα), accelerated hypoxia-inducible factor-1α stabilization by tumor cells in obese mice impedes the upregulation of FAO, which contributes to its chemoresistance. Finally, this work finds that improving FAO by PPARα activation ameliorates obesity-driven chemoresistance and enhances the outcomes of chemotherapy in obese mice. These findings reveal the shift toward FAO induction is an important metabolic response to DNA damage and may provide effective therapeutic strategies for cancer patients with obesity.


Subject(s)
Fatty Acids , PPAR alpha , Mice , Animals , Humans , Oxidation-Reduction , Fatty Acids/metabolism , PPAR alpha/metabolism , Mice, Obese , Drug Resistance, Neoplasm , Obesity/metabolism , Cell Death
5.
Molecules ; 28(19)2023 Oct 09.
Article in English | MEDLINE | ID: mdl-37836838

ABSTRACT

The recent rapid growth of the battery industry has led to a rapid increase in methylene chloride emissions. Methylene chloride causes health and social problems in humans. In this study, cellulose-based activated carbon fibers (CACFs) with improved yield were prepared for the removal of methylene chloride. The concentration of ammonium phosphate in the pretreatment controlled the crosslink density of cellulose fibers and improved the yield. From the results, the specific surface area and total pore volume of cellulose-based activated carbon fibers pretreated with ammonium phosphate (AP-CACFs) were determined to be 1920-2060 m2/g and 0.83-1.02 cm3/g, respectively, and the total yield improved by 6.78-11.59% compared to that of CACFs (4.97%). In particular, a correlation between the textural properties of CACFs and methylene chloride adsorption/desorption behavior was obtained. This correlation can be used to develop efficient adsorbents for methylene chloride removal.

6.
Sci Rep ; 13(1): 17494, 2023 10 15.
Article in English | MEDLINE | ID: mdl-37840076

ABSTRACT

Using aqueous precursors, we report successfully fabricating thin-solid films of two nucleic acids, ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). We investigated the potential of these films deposited on a fiber optic platform as all-fiber integrated saturable absorbers (SAs) for ultrafast nonlinear optics. RNA-SA performances were comparable to those of DNA-SA in terms of its nonlinear transmission, modulation depth, and saturation intensity. Upon insertion of these devices into an Erbium-doped fiber ring-laser cavity, both RNA and DNA SAs enabled efficient passive Q-switching operation. RNA-SA application further facilitated robust mode-locking and generated a transform-limited soliton pulse, exhibiting a pulse duration of 633 femtoseconds. A detailed analysis of these pulsed laser characteristics compared RNA and DNA fiber optic SAs with other nonlinear optic materials. The findings of this research establish the feasibility of utilizing RNA as a saturable absorber in ultrafast laser systems with an equal or higher potential as DNA, which presents novel possibilities for the nonlinear photonic applications of nucleic acid thin solid films.


Subject(s)
Nucleic Acids , Motion Pictures , RNA , Lasers , DNA
7.
J Anal Toxicol ; 47(9): 867-870, 2023 Dec 12.
Article in English | MEDLINE | ID: mdl-37756625

ABSTRACT

Thiocyanate is an inorganic compound used in industrial applications. Here, we report a case of suicidal death due to acute thiocyanate overdose. A 44-year-old man who consumed an unknown amount of thiocyanate solution was transferred to the emergency room and died 2 h after admission. An autopsy was performed 2 days after death. General toxicological analysis of blood using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry found no drug or alcohol. Quantification using GC-MS post-derivatization with pentafluorobenzyl bromide revealed 2,290 and 1,920 mg/L of thiocyanate in the heart and femoral blood samples, respectively. Thus, the cause of death was attributed to thiocyanate overdose. This study provides useful information for the interpretation of thiocyanate-related fatalities.


Subject(s)
Drug Overdose , Thiocyanates , Male , Humans , Adult , Gas Chromatography-Mass Spectrometry , Drug Overdose/diagnosis , Autopsy
8.
Micromachines (Basel) ; 14(9)2023 Sep 14.
Article in English | MEDLINE | ID: mdl-37763929

ABSTRACT

Selective laser etching is a promising candidate for the mass production of glass interposers. It comprises two steps: local modification by an ultrashort-pulsed laser and chemical etching of the modified volume. According to previous studies, when an ultrashort-pulsed laser beam is irradiated on the sample, electron excitation occurs, followed by phonon vibration. In general, the electron excitation occurs for less than a few tens of picoseconds and phonon vibration occurs for more than 100 picoseconds. Thus, in order to compare the electric absorption and thermal absorption of photons in the commercial glass, we attempt to implement an additional laser pulse of 213 ps and 10 ns after the first pulse. The modified glass sample is etched with 8 mol/L KOH solution with 110 °C to verify the effect. Here, we found that the electric absorption of photons is more effective than the thermal absorption of them. We can claim that this result helps to enhance the process speed of TGV generation.

9.
Polymers (Basel) ; 15(18)2023 Sep 16.
Article in English | MEDLINE | ID: mdl-37765638

ABSTRACT

The interfacial adhesion between carbon fibers (CFs) and a thermoplastic matrix is an important aspect that should be improved in manufacturing CF-reinforced thermoplastics with high strength and rigidity. In this study, the effects of a two-step surface treatment comprising electrochemical oxidation and silane treatment of the CF surface on the mechanical properties of CF/maleic anhydride-grafted polypropylene (MAPP) composites were confirmed. The surface characteristics of the treated CFs were analyzed via scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The tensile testing of a single CF and interfacial adhesion of the samples before and after the surface treatment were analyzed using a single-fiber testing machine and a universal testing machine. After the silane treatment, the roughness of the CF surface increased due to the formation of a siloxane network. In addition, the interfacial shear strength increased by ∼450% compared to that of the untreated CFs due to the covalent bond between the -NH2 end group of siloxane and MAPP. This two-step surface treatment, which can be performed continuously, is considered an effective method for improving the mechanical interface strength between the CF and polymer matrix.

10.
Materials (Basel) ; 16(16)2023 Aug 15.
Article in English | MEDLINE | ID: mdl-37629916

ABSTRACT

In this study, the activated carbon was prepared with superior CO2 selective adsorption properties using walnut shells, a biomass waste, as a precursor. The activations were conducted at various times using the microwave heating technique in a steam atmosphere. The surface morphology and chemical composition of activated carbon were analyzed using a scanning electron microscope and energy-dispersive X-ray spectroscopy. The textural properties were investigated using the N2/77K isothermal method, and the structural characteristics were examined using X-ray diffraction analysis. The CO2 and H2 adsorption properties of activated carbon were analyzed using a thermogravimetric analyzer and a high-pressure isothermal adsorption apparatus, respectively, under atmospheric and high-pressure conditions. Depending on the activation time, the specific surface area and total pore volume of the activated carbon were 570-690 m2/g and 0.26-0.34 cm3/g, respectively. The adsorption behaviors of CO2 of the activated carbon were different under atmospheric and high-pressure conditions. At atmospheric pressure, a significant dependence on micropores with diameters less than 0.8 nm was observed, whereas, at high pressure, the micropores and mesopores in the range of 1.6-2.4 nm exhibited a significant dependence. However, H2 adsorption did not occur at relatively low pressures. Consequently, the prepared activated carbon exhibited superior selective adsorption properties for CO2.

11.
Nanomaterials (Basel) ; 13(16)2023 Aug 10.
Article in English | MEDLINE | ID: mdl-37630882

ABSTRACT

Activated carbon fibers (ACFs) are beneficial for adsorbing harmful gases because of the well-developed micropores on their surface. Usually, the physical adsorption of harmful gases by ACFs is limited by their textural properties. In this study, the effect of nickel particle catalyst impregnation on the physicochemical removal of nitric oxide (NO) by polyimide (PI)-based ACFs (PI-ACFs) was investigated. Ni(NO3)2 was used as the precursor of nickel particle catalysts and impregnated on ACFs as a function of concentrations. The Ni(NO3)2/ACFs were then thermally reduced in an argon atmosphere containing 4% hydrogen (400 °C, 1 h). The gases generated during heat treatment were verified using Fourier transform infrared spectroscopy, and the impregnation amount of metallic nickel was also calculated based on the gas amount generated. The specific surface areas of the ACF and Ni-ACFs were determined to be 1010-1180 m2/g, while the nickel impregnation amount was 0.85-5.28 mg/g. The NO removal capacity of the Ni-ACF was found to be enhanced with the addition of Ni catalysts. In addition, metallic nickel particles on the ACFs maintained their chemical molecular structures before and after the NO removal tests.a.

12.
Polymers (Basel) ; 15(16)2023 Aug 19.
Article in English | MEDLINE | ID: mdl-37631528

ABSTRACT

Activated carbon (AC) and activated carbon fibers (ACFs) are materials with a large specific surface area and excellent physical adsorption properties due to their rich porous structure, and they are used as electrode materials to improve the performance of adsorbents or capacitors. Recently, multiple studies have confirmed the applicability of AC/polymer compo-sites in various fields by exploiting the unique physical and chemical properties of AC. As the excellent mechanical properties, stability, antistatic and electromagnetic interference (EMI) shielding functions of activated carbon/polymer composite materials were confirmed in recent studies, it is expected that activated carbon can be utilized as an ideal reinforcing material for low-cost polymer composite materials. Therefore, in this review, we would like to describe the fabrication, characterization and applicability of AC/polymer composites.

13.
Oncogene ; 42(38): 2828-2840, 2023 09.
Article in English | MEDLINE | ID: mdl-37591953

ABSTRACT

Proliferating cells have metabolic dependence on glutamine to fuel anabolic pathways and to refill the mitochondrial carbon pool. The Hippo pathway is essential for coordinating cell survival and growth with nutrient availability, but no molecular connection to glutamine deprivation has been reported. Here, we identify a non-canonical role of YAP, a key effector of the Hippo pathway, in cellular adaptation to perturbation of glutamine metabolism. Whereas YAP is inhibited by nutrient scarcity, enabling cells to restrain proliferation and to maintain energy homeostasis, glutamine shortage induces a rapid YAP dephosphorylation and activation. Upon glutaminolysis inhibition, an increased reactive oxygen species production inhibits LATS kinase via RhoA, leading to YAP dephosphorylation. Activated YAP promotes transcriptional induction of ATF4 to induce the expression of genes involved in amino acid homeostasis, including Sestrin2. We found that YAP-mediated Sestrin2 induction is crucial for cell viability during glutamine deprivation by suppressing mTORC1. Thus, a critical relationship between YAP, ATF4, and mTORC1 is uncovered by our findings. Finally, our data indicate that targeting the Hippo-YAP pathway in combination with glutaminolysis inhibition may provide potential therapeutic approaches to treat tumors.


Subject(s)
Activating Transcription Factor 4 , Glutamine , Humans , Activating Transcription Factor 4/metabolism , Cell Survival , Homeostasis , Mechanistic Target of Rapamycin Complex 1 , Mitochondria
14.
Chemistry ; 29(54): e202301938, 2023 Sep 26.
Article in English | MEDLINE | ID: mdl-37395682

ABSTRACT

A novel and flexible approach for the stereo-controlled synthesis of vicinal tertiary carbinols is reported. The developed strategy featured a highly diastereoselective singlet-oxygen (O2 1 ) [4+2] cycloaddition of rationally designed cyclohexadienones (derived from oxidative dearomatization of the corresponding carboxylic-acid appended phenol precursors), followed by programmed "O-O" and "C-C" bond cleavage. In doing so, a highly functionalized and versatile intermediate was identified and prepared in synthetically useful quantity as a plausible precursor to access a variety of designed and naturally occurring vicinal tertiary carbinol containing compounds. Most notably, the developed strategy was successfully applied in the stereo-controlled synthesis of advanced core structures of zaragozic acid, pactamycin and ryanodol.

15.
Cell Death Dis ; 14(7): 435, 2023 07 15.
Article in English | MEDLINE | ID: mdl-37454129

ABSTRACT

DNA repair is a tightly coordinated stress response to DNA damage, which is critical for preserving genome integrity. Accruing evidence suggests that metabolic pathways have been correlated with cellular response to DNA damage. Here, we show that fatty acid oxidation (FAO) is a crucial regulator of DNA double-strand break repair, particularly homologous recombination repair. Mechanistically, FAO contributes to DNA repair by activating poly(ADP-ribose) polymerase 1 (PARP1), an enzyme that detects DNA breaks and promotes DNA repair pathway. Upon DNA damage, FAO facilitates PARP1 acetylation by providing acetyl-CoA, which is required for proper PARP1 activity. Indeed, cells reconstituted with PARP1 acetylation mutants display impaired DNA repair and enhanced sensitivity to DNA damage. Consequently, FAO inhibition reduces PARP1 activity, leading to increased genomic instability and decreased cell viability upon DNA damage. Finally, our data indicate that FAO serves as an important participant of cellular response to DNA damage, supporting DNA repair and genome stability.


Subject(s)
DNA Repair , DNA , Humans , Acetylation , DNA/metabolism , Poly (ADP-Ribose) Polymerase-1/metabolism , DNA Breaks, Double-Stranded , DNA Damage , Fatty Acids
16.
Nutrients ; 15(12)2023 Jun 06.
Article in English | MEDLINE | ID: mdl-37375548

ABSTRACT

For centuries, Foeniculi fructus (F. fructus) has been used as a traditional herbal medicine in China and Europe and is widely used as a natural therapy for digestive disorders, including indigestion, flatulence, and bloating. The mechanism of F. fructus that alleviates functional dyspepsia was analyzed through network pharmacology, and its therapeutic effect on an animal model of functional dyspepsia were investigated. The traditional Chinese medicine systems pharmacology (TCMSP) database was used to investigate the compounds, targets, and associated diseases of F. fructus. Information on the target genes was classified using the UniProtdatabase. Using the Cytoscape 3.9.1 software, a network was constructed, and the Cytoscape string application was employed to examine genes associated with functional dyspepsia. The efficacy of F. fructus on functional dyspepsia was confirmed by treatment with its extract in a mouse model of loperamide-induced functional dyspepsia. Seven compounds targeted twelve functional dyspepsia-associated genes. When compared to the control group, F. fructus exhibited significant suppression of symptoms in a mouse model of functional dyspepsia. The results of our animal studies indicated a close association between the mechanism of action of F. fructus and gastrointestinal motility. Based on animal experimental results, the results showed that F. fructus provided a potential means to treat functional dyspepsia, suggesting that its medical mechanism for functional dyspepsia could be described by the relationship between seven key compounds of F. fructus, including oleic acid, ß-sitosterol, and 12 functional dyspepsia-related genes.


Subject(s)
Drugs, Chinese Herbal , Dyspepsia , Animals , Mice , Dyspepsia/drug therapy , Drugs, Chinese Herbal/pharmacology , Drugs, Chinese Herbal/therapeutic use , Network Pharmacology , Medicine, Chinese Traditional , Disease Models, Animal , Molecular Docking Simulation
17.
Plants (Basel) ; 12(7)2023 Mar 30.
Article in English | MEDLINE | ID: mdl-37050134

ABSTRACT

Gastrointestinal motility disorder (GMD) is a disease that causes digestive problems due to inhibition of the movement of the gastrointestinal tract and is one of the diseases that reduce the quality of life of modern people. Smilacis Glabrae Rhixoma (SGR) is a traditional herbal medicine for many diseases and is sometimes prescribed to improve digestion. As a network pharmacological approach, we searched the TCMSP database for SGR, reviewed its constituents and target genes, and analyzed its relevance to gastrointestinal motility disorder. The effects of the SGR extract on the pacemaker activity in interstitial cells of Cajal (ICC) and gastric emptying were investigated. In addition, using the GMD mouse model through acetic acid (AA), we investigated the locomotor effect of SGR on the intestinal transit rate (ITR). As a result of network pharmacology analysis, 56 compounds out of 74 candidate compounds of SGR have targets, the number of targets is 390 targets, and there are 904 combinations. Seventeen compounds of SGR were related to GMD, and as a result of comparing the related genes with the GMD-related genes, 17 genes (active only) corresponded to both. When looking at the relationship network between GMD and SGR, it was confirmed that quercetin, resveratrol, SCN5A, TNF, and FOS were most closely related to GMD. In addition, the SGR extract regulated the pacemaker activity in ICC and recovered the delayed gastric emptying. As a result of feeding the SGR extract to AA-induced GMD mice, it was confirmed that the ITR decreased by AA was restored by the SGR extract. Through network pharmacology, it was confirmed that quercetin, resveratrol, SCN5A, TNF, and FOS were related to GMD in SGR, and these were closely related to intestinal motility. Based on these results, it is suggested that SGR in GMD restores digestion through the recovery of intestinal motility.

18.
Materials (Basel) ; 16(7)2023 Mar 24.
Article in English | MEDLINE | ID: mdl-37048898

ABSTRACT

In this study, carbon nanotubes (CNTs) were grown under the same conditions as those of carbon fibers and glass fibers, and a comparative analysis was performed to confirm the potential of glass fibers with grown CNTs as electromagnetic interference (EMI) shielding materials. The CNTs were grown directly on the two fiber surfaces by a chemical vapor deposition process, with the aid of Ni particles loaded on them via a Ni-P plating process followed by heat treatment. The morphology and structural characteristics of the carbon and glass fibers with grown CNTs were analyzed using scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectrometry (XPS), and the EMI shielding efficiency (EMI SE) of the directly grown CNT/carbon and glass fiber-reinforced epoxy matrix composites was determined using a vector-network analyzer. As the plating time increased, a plating layer serving as a catalyst formed on the fiber surface, confirming the growth of numerous nanowire-shaped CNTs. The average EMI SET values of the carbon fiber-reinforced plastic (CFRP) and glass fiber-reinforced plastic (GFRP) with grown CNTs maximized at approximately 81 and 40 dB, respectively. Carbon fibers with grown CNTs exhibited a significantly higher EMI SET value than the glass fiber-based sample, but the latter showed a higher EMI SET increase rate. This indicates that low-cost, high-quality EMI-shielding materials can be developed through the growth of CNTs on the surface of glass fibers.

19.
Article in English | MEDLINE | ID: mdl-37011037

ABSTRACT

The occurrence of zearalenone (ZEN) and its metabolites (α-zearalenol (α-ZEL), ß-zearalenol (ß-ZEL), α-zearalanol (α-ZAL), ß-zearalanol (ß-ZAL), and zearalanone (ZAN)) was investigated in 78 cereal flour from Korea using UHPLC-MS/MS. Among these mycotoxins, ZEN was the most abundant in the analyzed samples at an incidence rate of 41% and concentration range of 0.5-536 µg/kg. The highest contamination and incidence rate of ZEN were found in corn flour samples, while oat flour samples showed the lowest contamination and incidence rate of this mycotoxin. α-ZEL, ß-ZEL, and ZAN were detected only in corn flour samples but at lower frequencies of 23%, 17%, and 15%, respectively, while α-ZAL and ß-ZAL were not detected in any sample. To the best of our knowledge, this is the first investigation of the simultaneous occurrence of ZEN and its major metabolites in commercially available cereal flour from Korea. Among the tested samples, only four were contaminated with ZEN at levels exceeding the maximum regulatory level established in Korea. The co-occurrence of ZEN, α-ZEL, ß-ZEL, and ZAN was observed in 14% of all samples. Although ZEN metabolites were detected at relatively lower levels than ZEN, the relatively high co-occurrence rate of those mycotoxins is of significant concern from a food safety perspective, since they can synergistically contribute to the overall toxicity and estrogenic effects.


Subject(s)
Mycotoxins , Zearalenone , Zearalenone/analysis , Flour , Edible Grain/chemistry , Tandem Mass Spectrometry , Mycotoxins/toxicity , Republic of Korea
20.
Polymers (Basel) ; 15(5)2023 Feb 21.
Article in English | MEDLINE | ID: mdl-36904313

ABSTRACT

In this study, the effects of polyimide (PI) content and postcuring on thermal and mechanical properties in PI and epoxy (EP) blending systems were investigated. EP/PI (EPI) blending reduced the crosslinking density and improved the flexural and impact strength due to ductility. On the other hand, in the postcuring of EPI, the thermal resistance improved due to the increased crosslinking density and the flexural strength increased by up to 57.89% due to the enhanced stiffness, but the impact strength decreased by up to 59.54%. EPI blending induced the improvement in the mechanical properties of EP, and the postcuring process of EPI was shown to be an effective method to improve heat resistance. It was confirmed that EPI blending induces improvement in the mechanical properties of EP, and the postcuring process of EPI is an effective method for improving heat resistance.

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