Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 310
Filter
1.
J Korean Med Sci ; 39(18): e162, 2024 May 13.
Article in English | MEDLINE | ID: mdl-38742293

ABSTRACT

Hereditary hemolytic anemia (HHA) is considered a group of rare hematological diseases in Korea, primarily because of its unique ethnic characteristics and diagnostic challenges. Recently, the prevalence of HHA has increased in Korea, reflecting the increasing number of international marriages and increased awareness of the disease. In particular, the diagnosis of red blood cell (RBC) enzymopathy experienced a resurgence, given the advances in diagnostic techniques. In 2007, the RBC Disorder Working Party of the Korean Society of Hematology developed the Korean Standard Operating Procedure for the Diagnosis of Hereditary Hemolytic Anemia, which has been continuously updated since then. The latest Korean clinical practice guidelines for diagnosing HHA recommends performing next-generation sequencing as a preliminary step before analyzing RBC membrane proteins and enzymes. Recent breakthroughs in molecular genetic testing methods, particularly next-generation sequencing, are proving critical in identifying and providing insight into cases of HHA with previously unknown diagnoses. These innovative molecular genetic testing methods have now become important tools for the management and care planning of patients with HHA. This review aims to provide a comprehensive overview of recent advances in molecular genetic testing for the diagnosis of HHA, with particular emphasis on the Korean context.


Subject(s)
Anemia, Hemolytic, Congenital , Genetic Testing , High-Throughput Nucleotide Sequencing , Humans , Republic of Korea , Anemia, Hemolytic, Congenital/diagnosis , Anemia, Hemolytic, Congenital/genetics
2.
Materials (Basel) ; 17(8)2024 Apr 18.
Article in English | MEDLINE | ID: mdl-38673216

ABSTRACT

In this study, composite particles of rGO/CoFe2O4 were synthesized using a solvothermal method to fabricate a low-density magnetorheological (MR) material with enhanced sedimentation stability. The morphology and crystallographic features of rGO/CoFe2O4 were characterized via SEM, TEM, and XRD, and its magnetic properties were tested using VSM. The MR fluid was formulated by blending rGO/CoFe2O4 particles into silicone oil. Under different magnet strengths (H), a rotational rheometer was used to test its MR properties. Typical MR properties were observed, including shear stress, viscosity, storage/loss modulus, and dynamic yield stress (τdy) following the Herschel-Bulkley model reaching 200 Pa when H is 342 kA/m. Furthermore, the yield stress of the MR fluid follows a power law relation as H increases and the index changes from 2.0 (in the low H region) to 1.5 (in the high H region). Finally, its MR efficiency was calculated to be about 104% at H of 342 kA/m.

4.
ACS Nano ; 18(10): 7570-7579, 2024 Mar 12.
Article in English | MEDLINE | ID: mdl-38377437

ABSTRACT

Organic-inorganic hybrid perovskites (OIHPs) are a promising class of materials that rival conventional semiconductors in various optoelectronic applications. However, unraveling the precise nature of their low-energy electronic structures continues to pose a significant challenge, primarily due to the absence of clear band measurements. Here, we investigate the low-energy electronic structure of CH3NH3PbI3 (MAPI3) using angle-resolved photoelectron spectroscopy combined with ab initio density functional theory. We successfully visualize the electronic structure of MAPI3 near the bulk valence band maximum by using a laboratory photon source (He Iα, 21.2 eV) at low temperature and explore its fundamental properties. The observed valence band exhibits a highly isotropic and parabolic band characterized by small effective masses of 0.20-0.21 me, without notable spectral signatures associated with a large polaron or the Rashba effect, subjects that are intensely debated in the literature. Concurrently, our spin-resolved measurements directly disprove the giant Rashba scenario previously suggested in a similar perovskite compound by establishing an upper limit for the Rashba parameter (αR) of 0.28 eV Å. Our results unveil the unusually complex nature of the low-energy electronic structure of OIHPs, thereby advancing our fundamental understanding of this important class of materials.

5.
Epilepsia ; 65(4): 833-845, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38345387

ABSTRACT

The field of epilepsy has undergone substantial advances as we develop novel drugs and devices. Yet considerable challenges remain in developing broadly effective, well-tolerated treatments, but also precision treatments for rare epilepsies and seizure-monitoring devices. We summarize major recent and ongoing innovations in diagnostic and therapeutic products presented at the seventeenth Epilepsy Therapies & Diagnostics Development (ETDD) conference, which occurred May 31 to June 2, 2023, in Aventura, Florida. Therapeutics under development are targeting genetics, ion channels and other neurotransmitters, and many other potentially first-in-class interventions such as stem cells, glycogen metabolism, cholesterol, the gut microbiome, and novel modalities for delivering electrical neuromodulation.


Subject(s)
Anticonvulsants , Epilepsy , Humans , Anticonvulsants/therapeutic use , Epilepsy/drug therapy , Epilepsy/diagnosis , Seizures/drug therapy
6.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1869(3): 159453, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38244675

ABSTRACT

Vascular smooth muscle cell (VSMC) senescence promotes atherosclerosis via lipid-mediated mitochondrial dysfunction and oxidative stress. However, the mechanisms of mitochondrial dysfunction and VSMC senescence in atherosclerosis have not been established. Here, we investigated the mechanisms whereby signaling pathways regulated by SRT1720 enhance or regulate mitochondrial functions in atherosclerotic VSMCs to suppress atherosclerosis. Initially, we examined the effect of SRT1720 on oleic acid (OA)-induced atherosclerosis. Atherosclerotic VSMCs exhibited elevated expressions of BODIPY and ADRP (adipose differentiation-related protein) and associated intracellular lipid droplet markers. In addition, the expression of collagen I was upregulated by OA, while the expressions of elastin and α-SMA were downregulated. mtDNA copy numbers, an ATP detection assay, transmission electron microscopy (TEM) imaging of mitochondria, mitochondria membrane potentials (assessed using JC-1 probe), and levels of mitochondrial oxidative phosphorylation (OXPHOS) were used to examine the effects of SRT1720 on OA-induced mitochondrial dysfunction. SRT1720 reduced mtDNA damage and accelerated mitochondria repair in VSMCs with OA-induced mitochondria dysfunction. In addition, mitochondrial reactive oxygen species (mtROS) levels were downregulated by SRT1720 in OA-treated VSMCs. Importantly, SRT1720 significantly increased SIRT1 and PGC-1α expression levels, but VSMCs senescence, inflammatory response, and atherosclerosis phenotypes were not recovered by treating cells with EX527 and SR-18292 before SRT1720. Mechanistically, the upregulations of SIRT1 and PGC-1α deacetylation by SRT1720 restored mitochondrial function, and consequently suppressed VSMC senescence and atherosclerosis-associated proteins and phenotypes. Collectively, this study indicates that SRT1720 can attenuate OA-induced atherosclerosis associated with VSMC senescence and mitochondrial dysfunction via SIRT1-mediated deacetylation of the PGC-1α pathway.


Subject(s)
Atherosclerosis , Heterocyclic Compounds, 4 or More Rings , Mitochondrial Diseases , Atherosclerosis/genetics , Atherosclerosis/metabolism , DNA, Mitochondrial/metabolism , Mitochondria/metabolism , Mitochondrial Diseases/metabolism , Sirtuin 1/genetics , Sirtuin 1/metabolism
7.
Small ; 20(6): e2305272, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37702152

ABSTRACT

The magnetomechanical actuation of micropillars is developed for the contactless manipulation of miniaturized actuators and microtextured surfaces. Anisotropic geometry of micropillars can significantly enhance the magnetic actuation compared with their isotropic counterparts by directional stress distributions. However, this strategy is not viable for triangular micropillars owing to insufficient anisotropy. In this study, a significant improvement in the magnetic actuation of triangular micropillars using composite magnetic particles is reported. A minute and optimal amount of hard magnetic gamma-ferrite nanorods are hybridized with soft magnetic iron microspheres to generate synergistic effects of magnetic coupling and percolation phenomenon on the magnetic actuation of polymer composites. The addition of 1 wt% face-centered cubic-phased gamma-ferrite nanorods suppresses the magnetic coupling interference of body-centered cubic-phased iron microspheres. Furthermore, the nanorods reduce the percolation threshold by participating in the percolation of the microspheres. A systematic compositional study on the magnetization and magnetorheological properties reveals that the coupling effect dominates the percolation effect at a low magnetic field, whereas the percolation effect governs the magnetic actuation at a high magnetic field. This hybrid approach can help in designing material constituents for effective magnetic actuators and robotic systems that can sensitively respond to an external magnetic field.

8.
Epilepsia ; 65(4): 846-860, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38135921

ABSTRACT

Substantial efforts are underway toward optimizing the diagnosis, monitoring, and treatment of seizures and epilepsy. We describe preclinical programs in place for screening investigational therapeutic candidates in animal models, with particular attention to identifying and eliminating drugs that might paradoxically aggravate seizure burden. After preclinical development, we discuss challenges and solutions in the design and regulatory logistics of clinical trial execution, and efforts to develop disease biomarkers and interventions that may be not only seizure-suppressing, but also disease-modifying. As disease-modifying treatments are designed, there is clear recognition that, although seizures represent one critical therapeutic target, targeting nonseizure outcomes like cognitive development or functional outcomes requires changes to traditional designs. This reflects our increasing understanding that epilepsy is a disease with profound impact on quality of life for the patient and caregivers due to both seizures themselves and other nonseizure factors. This review examines selected key challenges and future directions in epilepsy diagnostics and therapeutics, from drug discovery to translational application.


Subject(s)
Anticonvulsants , Epilepsy , Animals , Humans , Anticonvulsants/therapeutic use , Quality of Life , Epilepsy/diagnosis , Epilepsy/drug therapy , Seizures/drug therapy , Disease Models, Animal
9.
Int Neurourol J ; 27(Suppl 2): S99-103, 2023 Nov.
Article in English | MEDLINE | ID: mdl-38048824

ABSTRACT

PURPOSE: Urinary stones cause lateral abdominal pain and are a prevalent condition among younger age groups. The diagnosis typically involves assessing symptoms, conducting physical examinations, performing urine tests, and utilizing radiological imaging. Artificial intelligence models have demonstrated remarkable capabilities in detecting stones. However, due to insufficient datasets, the performance of these models has not reached a level suitable for practical application. Consequently, this study introduces a vision transformer (ViT)-based pipeline for detecting urinary stones, using computed tomography images with augmentation. METHODS: The super-resolution convolutional neural network (SRCNN) model was employed to enhance the resolution of a given dataset, followed by data augmentation using CycleGAN. Subsequently, the ViT model facilitated the detection and classification of urinary tract stones. The model's performance was evaluated using accuracy, precision, and recall as metrics. RESULTS: The deep learning model based on ViT showed superior performance compared to other existing models. Furthermore, the performance increased with the size of the backbone model. CONCLUSION: The study proposes a way to utilize medical data to improve the diagnosis of urinary tract stones. SRCNN was used for data preprocessing to enhance resolution, while CycleGAN was utilized for data augmentation. The ViT model was utilized for stone detection, and its performance was validated through metrics such as accuracy, sensitivity, specificity, and the F1 score. It is anticipated that this research will aid in the early diagnosis and treatment of urinary tract stones, thereby improving the efficiency of medical personnel.

10.
Micromachines (Basel) ; 14(11)2023 Nov 04.
Article in English | MEDLINE | ID: mdl-38004918

ABSTRACT

In this work, environmentally friendly and low-cost passive electrical components (PECs) are manufactured based on composites consisting of cotton fabrics soaked with solutions of silicone oil and different amounts of iron oxides microfibers (µFe). The µFe consists of a mixture of three phases: hematite (α-Fe2O3), maghemite (γ-Fe2O3), and magnetite (Fe3O4). The equivalent electrical capacitance (Cp) and resistance (Rp) of PECs are measured as a function of magnetic flux density B in a static and pulsed magnetic field superimposed on an alternating electric field of frequency 1 kHz. The relative variation in the hysteresis curves for both Cp and Rp are obtained by measuring them in the ascending and then the descending mode of B. We show that all these three quantities are sensibly influenced by the volume fractions of µFe and by the values of B. The main influence on this behavior is attributed to the semiconductor properties of the α-Fe2O3 and γ-Fe2O3 components of the oxide microfibers. In addition, it is found that at B≃ 175 mT, the maximum relative variance of the hysteresis curve is about 3.35% for Cp and 3.18 % for Rp. When a pulsed magnetic field is used, it is shown that Cp and Rp closely follow the variation in the magnetic field. Thus, the resulting electrical properties of PECs, together with the fast response to the application of pulsed magnetic fields, make them useful in the fabrication of various devices, such as electric, magnetic, and deformation fields, or mechanical stress sensors with applications in protection against electromagnetic smog, healthcare monitoring, or for human-machine interfacing.

11.
Biochem Pharmacol ; 218: 115892, 2023 12.
Article in English | MEDLINE | ID: mdl-37890594

ABSTRACT

Cellular senescence is caused by diverse stimuli and contributes to cardiovascular diseases. Several studies have indicated that PPARγ acts as a key mediator of lipid metabolism and shown that it has a protective effect on vascular biology. Nevertheless, the mechanism responsible for the anti-aging effects of PPARγ has not been fully elucidated in vascular smooth muscle cell (VSMC). Furthermore, although mTOR complex 2 (mTORC2) is known to be involved in cellular senescence and autophagy, relatively few studies have investigated its effects as compared with mTOR complex 1 (mTORC1). Therefore, we focused on mTORC2 function and investigated the relationship between PPARγ and mTORC2, and the anti-aging mechanism in VSMC. We found PPARγ activation dose-dependently mitigated the hydrogen peroxide (H2O2)-induced senescence. Treatment of fisetin induced the translocation of PPARγ from cytosol to nuclear and inhibited VSMC senescence. Moreover, activated PPARγ increased PTEN transcription, leading to inhibition of the mTORC2 signaling pathway. We determined mTORC2 activation contributed to senescence by suppressing the FoxO3a-autophagy signaling pathway, and dual knockdown of mTORC1 and mTORC2 decreased cellular senescence and increased autophagy activation more than respective single knockdown. Finally, fisetin acted as a PPARγ activator and inhibited VSMC senescence through the mTORC2-FoxO3a-autophagy signaling pathway. These results demonstrate PPARγ is associated with cellular senescence and that fisetin has an anti-aging effect via PPARγ activation and mTORC2 inhibition in VSMC. These results demonstrate that the mTORC2 signaling pathway regulates autophagy and cellular senescence, which suggests mTORC2 should be considered a significant target for preventing cellular senescence and age-related diseases.


Subject(s)
Muscle, Smooth, Vascular , PPAR gamma , Muscle, Smooth, Vascular/metabolism , PPAR gamma/genetics , PPAR gamma/metabolism , Hydrogen Peroxide/metabolism , Signal Transduction , Cellular Senescence , Mechanistic Target of Rapamycin Complex 1/metabolism , Mechanistic Target of Rapamycin Complex 2/metabolism , Autophagy
12.
J Cell Biochem ; 124(10): 1615-1627, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37682868

ABSTRACT

The MYCC and MYCN loci are each associated with two upstream open reading frames (uORFs) potentially encoding small proteins (9-21 kDa). We previously demonstrated that uORFs mrtl and MYCHEX1 of MYCC are translated, and their protein products may function to regulate the expression of the "parent" oncogene. We hypothesized that a similar relationship might exist between MYCN and its two uORFs: MYCNOT and MNOP, and investigated the uORF-encoded proteins associated with MYCN to confirm their expression and intracellular location in neuroblastoma and medulloblastoma cells and tissues. MNOP, MYCNOT, mrtl, and MYCHEX1 were readily detected via reverse transcription polymerase chain reaction and Western blot analysis in tumor cell lines. In tumor tissue, MNOP protein expression was confirmed; however, MCYNOT generated from alternative splicing MYCNΔ1b mRNA was not detected. Immunofluorescence staining of MYCNOT displayed multiple bright foci in the nucleus and diffuse staining in the cytoplasm, suggesting that this small protein may function in both the nucleus and cytoplasm. Upon JQ1 treatment, MYCN, MYCNOT, and mrtl decreased substantially or disappeared completely in three different tumor cell lines. Significant levels of apoptosis were observed in each pediatric embryonal tumor cell line but not T47D breast carcinoma cells, suggesting that response to JQ1 transcriptional inhibition is greatest in tumor cells, which depend on MYC to maintain an undifferentiated phenotype. In conclusion, both MYCN uORF-encoded proteins MNOP and MYCNOT, together with the two MYCC uORF-encoded proteins mrtl and MYCHEX1 were detected simultaneously in tumor cell lines and tumor tissues. These four distinct proteins are translated from the "5'-untranslated region" of MYCN or MYCC mRNA and display consistent distribution patterns within the cell. Additional studies to further elucidate the physiological and pathological roles of these uORF-encoded proteins are warranted, as insights gained could inform new strategies for modulating MYC-family oncogenes by targeting their uORFs.

13.
ACS Nano ; 17(14): 13938-13947, 2023 Jul 25.
Article in English | MEDLINE | ID: mdl-37410957

ABSTRACT

The application of two-dimensional materials has been expanded by introducing the twisted bilayer (TBL) system. However, the landscape of the interlayer interaction in hetero-TBLs has not yet been fully understood, while that in homo-TBLs has been extensively studied, with the dependence on the twist angle between the constituent layers. Here, we present detailed analyses on the interlayer interaction that depends on the twist angle in WSe2/MoSe2 hetero-TBL via Raman and photoluminescence studies combined with first-principles calculation. We observe interlayer vibrational modes, moiré phonons, and the interlayer excitonic states that evolve with the twist angle and identify different regimes with distinct characteristics of such features. Moreover, the interlayer excitons that appear strong in the hetero-TBLs with twist angles near 0° or 60° have different energies and photoluminescence excitation spectra for the two cases, which results from different electronic structures and carrier relaxation dynamics. These results would enable a better understanding of the interlayer interaction in hetero-TBLs.

14.
JMIR Form Res ; 7: e37553, 2023 Jun 12.
Article in English | MEDLINE | ID: mdl-37307035

ABSTRACT

BACKGROUND: According to a 2020 study by the American Cancer Society, colorectal cancer (CRC) represents the third leading cause of cancer both in incidence and death in the United States. Nonetheless, CRC screening remains lower than that for other high-risk cancers such as breast and cervical cancer. Risk calculators are increasingly being used to promote cancer awareness and improve compliance with CRC screening tests. However, research concerning the effects of CRC risk calculators on the intention to undergo CRC screening has been limited. Moreover, some studies have found the impacts of CRC risk calculators to be inconsistent, reporting that receiving personalized assessments from such calculators lowers people's risk perception. OBJECTIVE: The objective of this study is to examine the effect of using CRC risk calculators on individuals' intentions to undergo CRC screening. In addition, this study aims to examine the mechanisms through which using CRC risk calculators might influence individuals' intentions to undergo CRC screening. Specifically, this study focuses on the role of perceived susceptibility to CRC as a potential mechanism mediating the effect of using CRC risk calculators. Finally, this study examines how the effect of using CRC risk calculators on individuals' intentions to undergo CRC screening may vary by gender. METHODS: We recruited a total of 128 participants through Amazon Mechanical Turk who live in the United States, have health insurance, and are in the age group of 45 to 85 years. All participants answered questions needed as input for the CRC risk calculator but were randomly assigned to treatment (CRC risk calculator results immediately received) and control (CRC risk calculator results made available after the experiment ended) groups. The participants in both groups answered a series of questions regarding demographics, perceived susceptibility to CRC, and their intention to get screened. RESULTS: We found that using CRC risk calculators (ie, answering questions needed as input and receiving calculator results) has a positive effect on intentions to undergo CRC screening, but only for men. For women, using CRC risk calculators has a negative effect on their perceived susceptibility to CRC, which in turn reduces the intention to sign up for CRC screening. Additional simple slope and subgroup analyses confirm that the effect of perceived susceptibility on CRC screening intention is moderated by gender. CONCLUSIONS: This study shows that using CRC risk calculators can increase individuals' intentions to undergo CRC screening, but only for men. For women, using CRC risk calculators can reduce their intentions to undergo CRC screening, as it reduces their perceived susceptibility to CRC. Given these mixed results, although CRC risk calculators can be a useful source of information on one's CRC risk, patients should be discouraged from relying solely on them to inform decisions regarding CRC screening.

15.
Int Neurourol J ; 27(Suppl 1): S21-26, 2023 May.
Article in English | MEDLINE | ID: mdl-37280756

ABSTRACT

PURPOSE: Urolithiasis is a common disease that can cause acute pain and complications. The objective of this study was to develop a deep learning model utilizing transfer learning for the rapid and accurate detection of urinary tract stones. By employing this method, we aim to improve the efficiency of medical staff and contribute to the progress of deep learning-based medical image diagnostic technology. METHODS: The ResNet50 model was employed to develop feature extractors for detecting urinary tract stones. Transfer learning was applied by utilizing the weights of pretrained models as initial values, and the models were fine-tuned with the provided data. The model's performance was evaluated using accuracy, precision-recall, and receiver operating characteristic curve metrics. RESULTS: The ResNet-50-based deep learning model demonstrated high accuracy and sensitivity, outperforming traditional methods. Specifically, it enabled a rapid diagnosis of the presence or absence of urinary tract stones, thereby assisting doctors in their decision-making process. CONCLUSION: This research makes a meaningful contribution by accelerating the clinical implementation of urinary tract stone detection technology utilizing ResNet-50. The deep learning model can swiftly identify the presence or absence of urinary tract stones, thereby enhancing the efficiency of medical staff. We expect that this study will contribute to the advancement of medical imaging diagnostic technology based on deep learning.

16.
J Pediatr ; 260: 113515, 2023 09.
Article in English | MEDLINE | ID: mdl-37244579

ABSTRACT

OBJECTIVE: To outline the characteristics of Kikuchi-Fujimoto disease (KFD) in children and analyze factors associated with severe and recurring courses. METHODS: Electronic medical records of children histopathologically diagnosed with KFD at Seoul National University Bundang Hospital from March 2015 to April 2021 were retrospectively reviewed. RESULTS: A total of 114 cases (62 males) were identified. The mean patient age was 12.0 ± 3.5 years. Most patients came to medical attention with cervical lymph node enlargement (97.4%) and fever (85%); 62% had a high-grade fever (≥39°C). Prolonged fever (≥14 days) was seen in 44.3% and was associated with a high-grade fever (P = .004). Splenomegaly, oral ulcer, or rash was present in 10.5%, 9.6%, and 15.8%, respectively. Laboratory findings showed leukopenia, anemia, and thrombocytopenia in 74.1%, 49%, and 24%, respectively. Sixty percent of cases had a self-limited course. Antibiotics were initially prescribed in 20%. A corticosteroid was prescribed in 40% of patients and was associated with oral ulcer (P = .045) and anemia (P = .025). Twelve patients (10.5%) had a recurrence with a median interval of 19 months. No risk factor for recurrence was identified in multivariable analysis. Clinical characteristics of KFD were similar between our current and previous studies. However, antibiotics use decreased (P < .001); nonsteroidal anti-inflammatory drugs use increased (P < .001), and, although statistically not significant, corticosteroid treatment also increased. CONCLUSIONS: Over a span of 18 years, the clinical characteristics of KFD did not change. Patients presenting with high-grade fever, oral ulcer, or anemia may benefit from corticosteroid intervention. All patients should be monitored for recurrence.


Subject(s)
Histiocytic Necrotizing Lymphadenitis , Leukopenia , Oral Ulcer , Male , Humans , Child , Adolescent , Histiocytic Necrotizing Lymphadenitis/complications , Histiocytic Necrotizing Lymphadenitis/diagnosis , Retrospective Studies , Oral Ulcer/complications , Oral Ulcer/drug therapy , Adrenal Cortex Hormones/therapeutic use , Fever/complications , Anti-Bacterial Agents/therapeutic use , Leukopenia/drug therapy
17.
ACS Omega ; 8(15): 14190-14196, 2023 Apr 18.
Article in English | MEDLINE | ID: mdl-37091409

ABSTRACT

We have conducted a terahertz spectroscopic study and a density functional theory analysis of the phonon dynamics of the layered van der Waals semiconductors Nb3Cl8 and Nb3I8. Several infrared-active phonon modes were observed in the terahertz region, and their frequencies were found to be in excellent agreement with our first-principles lattice dynamics calculations. For Nb3Cl8, the observed phonon spectra are consistent with a structural transition at 90 K from the high-temperature P3̅m1 phase to the low-temperature R3̅m phase. Also, our study confirmed that the structural and magnetic transitions were coupled in Nb3Cl8. For Nb3I8, which is nonmagnetic at and below room temperature, no significant temperature or magnetic field dependence was observed in the phonon spectra. Our study provides an intriguing connection between the structural properties and the paramagnetic-nonmagnetic transitions in Nb3Cl8 and Nb3I8.

18.
Polymers (Basel) ; 15(8)2023 Apr 20.
Article in English | MEDLINE | ID: mdl-37112100

ABSTRACT

Thermoplastic starch was blended with commercially available biodegradable polyesters of poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) for its improved performance and processability. The morphology and elemental composition of these biodegradable polymer blends were observed by scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively, while their thermal properties were analyzed using thermogravimetric analysis and differential thermal calorimetry. For rheological analysis, the steady shear and dynamic oscillation tests of three samples at various temperatures were investigated using a rotational rheometer. All three samples exhibited significant shear thinning at all measured temperatures, and their shear viscosity behavior was plotted using the Carreau model. The frequency sweep tests showed that the thermoplastic starch sample exhibited a solid state at all temperatures tested, whereas both starch/PBAT and starch/PBAT/PLA blend samples exhibited viscoelastic liquid behavior after the melting temperature such that their loss modulus at low frequencies was greater than the storage modulus, and inversion occurred at high frequencies (storage modulus > loss modulus).

19.
Arch Gerontol Geriatr ; 108: 104927, 2023 05.
Article in English | MEDLINE | ID: mdl-36645971

ABSTRACT

Reactive oxygen species (ROS) are a key risk factor of cellular senescence and age-related diseases, and protein kinase C (PKC) has been shown to activate NADPH oxidases (NOXs), which generate ROS. Although PKC activation induces oxidative stress, leading to the cellular dysfunction in various cell types, the correlation between PKC and senescence has not been reported in vascular smooth muscle cell (VSMC). Several studies have indicated cellular senescence is accompanied by phosphatase and tensin homolog (PTEN) loss and that an interaction exists between PTEN and PKC. Therefore, we aimed to determine whether PTEN and PKC are associated with VSMC senescence and to investigate the mechanism involved. We found hydrogen peroxide (H2O2) decreased PTEN expression and increased PKCδ phosphorylation. Moreover, H2O2 upregulated the NOX1 subunits, p22phox and p47phox, and induced VSMC senescence via p53-p21 signaling pathway. We identified PKCδ activation contributed to VSMC senescence through activation of NOX1 and ROS production. However, fisetin inhibited cellular senescence induced by the PTEN-PKCδ-NOX1-ROS signaling pathway, and this anti-aging effect was attributed to reduced ROS production caused by suppressing NOX1 activation. These results suggest that the PTEN-PCKδ signaling pathway is directly related to senescence via NOX1 activation and that the downregulation of PKCδ by flavonoids provides a potential means of treating age-associated diseases.


Subject(s)
Hydrogen Peroxide , Muscle, Smooth, Vascular , Humans , Reactive Oxygen Species/metabolism , Reactive Oxygen Species/pharmacology , Muscle, Smooth, Vascular/metabolism , NADPH Oxidase 1/metabolism , NADPH Oxidase 1/pharmacology , Hydrogen Peroxide/metabolism , Hydrogen Peroxide/pharmacology , Cells, Cultured , Cellular Senescence , PTEN Phosphohydrolase/metabolism , PTEN Phosphohydrolase/pharmacology
20.
Cancer Res Treat ; 55(1): 279-290, 2023 Jan.
Article in English | MEDLINE | ID: mdl-35952715

ABSTRACT

PURPOSE: Renal tumors account for approximately 7% of all childhood cancers. These include Wilms tumor (WT), clear cell sarcoma of the kidney (CCSK), malignant rhabdoid tumor of the kidney (MRTK), renal cell carcinoma (RCC), congenital mesoblastic nephroma (CMN) and other rare tumors. We investigated the epidemiology of pediatric renal tumors in Korea. MATERIALS AND METHODS: From January 2001 to December 2015, data of pediatric patients (0-18 years) newly-diagnosed with renal tumors at 26 hospitals were retrospectively analyzed. RESULTS: Among 439 patients (male, 240), the most common tumor was WT (n=342, 77.9%), followed by RCC (n=36, 8.2%), CCSK (n=24, 5.5%), MRTK (n=16, 3.6%), CMN (n=12, 2.7%), and others (n=9, 2.1%). Median age at diagnosis was 27.1 months (range 0-225.5) and median follow-up duration was 88.5 months (range 0-211.6). Overall, 32 patients died, of whom 17, 11, 1, and 3 died of relapse, progressive disease, second malignant neoplasm, and treatment-related mortality. Five-year overall survival and event free survival were 97.2% and 84.8% in WT, 90.6% and 82.1% in RCC, 81.1% and 63.6% in CCSK, 60.3% and 56.2% in MRTK, and 100% and 91.7% in CMN, respectively (p < 0.001). CONCLUSION: The pediatric renal tumor types in Korea are similar to those previously reported in other countries. WT accounted for a large proportion and survival was excellent. Non-Wilms renal tumors included a variety of tumors and showed inferior outcome, especially MRTK. Further efforts are necessary to optimize the treatment and analyze the genetic characteristics of pediatric renal tumors in Korea.


Subject(s)
Carcinoma, Renal Cell , Kidney Neoplasms , Nephroma, Mesoblastic , Rhabdoid Tumor , Sarcoma , Wilms Tumor , Child , Humans , Male , Carcinoma, Renal Cell/epidemiology , Retrospective Studies , Neoplasm Recurrence, Local , Kidney Neoplasms/therapy , Kidney Neoplasms/drug therapy , Nephroma, Mesoblastic/congenital , Nephroma, Mesoblastic/metabolism , Nephroma, Mesoblastic/pathology , Rhabdoid Tumor/pathology , Republic of Korea/epidemiology
SELECTION OF CITATIONS
SEARCH DETAIL
...