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1.
Environ Pollut ; 359: 124525, 2024 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-39004206

RESUMEN

With aging population increasing globally, the use of pharmaceutically active compounds is rising. The cardiovascular drug telmisartan has been widely detected in various environmental compartments, including biota, surface waters, and sewage treatment plant effluents at concentrations ranging from ng/L to µg/L levels. This study evaluated the effects of telmisartan on the microcrustacean Daphnia magna at a wide range of concentrations (0.35, 0.70, 1.40, 500, and 1000 µg/L) and revealed significant ecotoxicological implications of this drug, even at environmentally relevant concentration. Acute exposure to telmisartan (1.40, 500, and 1000 µg/L) resulted in a notable decrease in heart rate, while chronic exposure accelerated the time to the first brood by 3 days and reduced neonate body size. Molecular investigations revealed marked downregulation of vitellogenin genes (Vtg1 and Vtg2). Non-monotonic dose responses were observed for gene expression, early-stage body length, and the total number of offspring produced, while the heart rate and time to the first brood showed clear concentration-dependent responses. These findings highlight the potential risks, notably to reproductive capacity, associated with exposure to telmisartan in environmentally relevant concentration, suggesting the need for further studies on the potential long-term ecological consequences.

2.
Mar Pollut Bull ; 206: 116764, 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39059220

RESUMEN

Comprehensive studies simultaneously investigating the occurrence of chemicals of concern are limited. In this study, sediments and bivalves were collected from 24 locations along the Korean coast to evaluate the relative distribution, contamination characteristics, and ecological risks of legacy/emerging persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs). Our findings reveal that the concentrations of these contaminants were comparable to or lower than historical levels in the same Korean coast and other Asian countries. Notably, PAHs exhibited the highest distribution in sediments (84 %), whereas short-chain chlorinated paraffins (SCCPs) were dominant in bivalves (91 %). This study highlighted significant correlations in the sediment levels of each legacy pollutants, suggesting similar sources and geochemical behaviors. However, SCCPs displayed unique contamination patterns. Ecologically, PAHs and SCCPs presented low risks in sediments compared to Canadian Sediment Quality Guidelines, however 100 % and 33 % of bivalves, respectively, exceeded US EPA/Canadian Fish Tissue Guidelines.

3.
Nanomicro Lett ; 16(1): 244, 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38990425

RESUMEN

Long-term societal prosperity depends on addressing the world's energy and environmental problems, and photocatalysis has emerged as a viable remedy. Improving the efficiency of photocatalytic processes is fundamentally achieved by optimizing the effective utilization of solar energy and enhancing the efficient separation of photogenerated charges. It has been demonstrated that the fabrication of III-V semiconductor-based photocatalysts is effective in increasing solar light absorption, long-term stability, large-scale production and promoting charge transfer. This focused review explores on the current developments in III-V semiconductor materials for solar-powered photocatalytic systems. The review explores on various subjects, including the advancement of III-V semiconductors, photocatalytic mechanisms, and their uses in H2 conversion, CO2 reduction, environmental remediation, and photocatalytic oxidation and reduction reactions. In order to design heterostructures, the review delves into basic concepts including solar light absorption and effective charge separation. It also highlights significant advancements in green energy systems for water splitting, emphasizing the significance of establishing eco-friendly systems for CO2 reduction and hydrogen production. The main purpose is to produce hydrogen through sustainable and ecologically friendly energy conversion. The review intends to foster the development of greener and more sustainable energy source by encouraging researchers and developers to focus on practical applications and advancements in solar-powered photocatalysis.

4.
Artículo en Inglés | MEDLINE | ID: mdl-38977483

RESUMEN

PURPOSE: Single-sided deafness (SSD) presents significant challenges for patients, including compromised sound localization, reduced speech recognition, and often, tinnitus. These issues are typically addressed using interventions such as cochlear implantation (CI) and bone conduction implant (BCI). However, evidence regarding the efficacy of BCI in reducing tinnitus in SSD patients remains limited. This study explored the ability of a novel active transcutaneous BCI (Bonebridge BCI602) to alleviate tinnitus in SSD patients. STUDY DESIGN: Prospective cohort multicenter study. SETTING: Tertiary referral hospitals. METHODS: A prospective multicenter study of 30 SSD patients was conducted. The patients were divided into two groups: those with (n = 19) and without (n = 11) tinnitus. Audiometric assessments, subjective questionnaires including the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Bern Benefit in Single-Sided Deafness (BBSS), and tinnitus evaluations with the Tinnitus Handicap Inventory (THI) and tinnitogram were conducted before and after BCI surgery. RESULTS: THI scores after surgery were significantly reduced in SSD patients with tinnitus. Subjective satisfaction improved in both the tinnitus and non-tinnitus groups; however, the former group exhibited a significantly greater improvement in the APHAB questionnaire score. According to tinnitograms, the loudness of tinnitus decreased, particularly in patients with ipsilateral tinnitus. Patients with residual hearing had greater reductions in their THI scores. However, three patients without residual hearing had a relative worsening of tinnitus after surgery. CONCLUSION: The Bonebridge BCI602 effectively reduced tinnitus in SSD patients, particularly in those with residual hearing. Subjective satisfaction improved in both the tinnitus and non-tinnitus groups. These findings demonstrate the therapeutic potential of BCI for managing SSD and associated tinnitus.

5.
J Hazard Mater ; 476: 135090, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-39024765

RESUMEN

Illicit drugs have become a crucial global social issue, with South Korea experiencing a continuous increase in the number of offenders and drug smuggling. This study employed wastewater-based epidemiology to investigate consumption patterns of 8 illicit drugs and their 7 metabolites during the COVID-19 pandemic (2020-2022) in South Korea. Ten compouds were detected in the wastewater influent. Methamphetamine (METH) was prevalent in samples, followed by amphetamine and ecstasy (MDMA). Interestingly, MDMA and ketamine (KET), which were not detected in previous Korean studies conducted before COVID-19 pandemic, were detected in this study. METH exhibited the highest consumption rates, decreasing from 16.6 to 12.4 mg/day/1000 people between 2020 and 2022, while MDMA increased over the three years (mean: 1.16, 1.24, and 1.62 mg/day/1000 people in 2020, 2021, and 2022, respectively) (p < 0.05). Significant correlations were identified between regional income levels and the consumption rates of METH (p < 0.01), MDMA (p < 0.01), and KET (p < 0.05). Furthermore, METH and MDMA consumption rates in cities were positively correlated with the number of drug offenders arrested and local clubs in those cities. The findings of this study provide valuable insights into shaping regulatory policies related to illicit drugs and future studies.

6.
Protein Sci ; 33(8): e5066, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39074259

RESUMEN

Affinity precipitation is an attractive method for protein purification due to its many advantages, including the rapid capture of target proteins, simple processing, high specificity, and ease of scale-up. We previously reported a robust antibody purification method using Ca2+-dependent precipitation of ZZ-hCSQ2, a fusion protein of human calsequestrin 2, and the antibody-binding protein ZZ. However, the stability of this fusion protein was not sufficiently high for industrial use because the antibody recovery yield decreased to 60% after being reused 10 times. To identify a more stable calsequestrin (CSQ), we calculated Rosetta energy values for the folding stabilities of various CSQ homologs and selected human CSQ1 (hCSQ1) with lowest energy value (-992.6) as the new CSQ platform. We also identified that the linker sequence between ZZ and CSQ was vulnerable to proteases and alkaline pH by N-terminal protein sequencing. Therefore, we changed the linker to four asparagine (4N) sequences, which were shorter and less flexible than the previous glycine-rich linker. The new version of ZZ-CSQ, ZZ-4N-hCSQ1, was stable in a protease-containing conditioned medium obtained from the cultured Chinese hamster ovary cell or high pH condition (0.1M sodium hydroxide) for more than 5 days and could be reused at least 25 times for antibody purification without loss of recovery yield. The antibodies purified by ZZ-4N-hCSQ1 precipitation also showed greater purity (~33.6-fold lower host cell DNA and ~6.4-fold lower host cell protein) than those purified by protein A chromatography. These data suggest that ZZ-4N-hCSQ1 precipitation is more efficient and can achieve cost-effectiveness of up to 12.5-fold cheaper than previous antibody purification methods and can lower the production costs of therapeutic antibodies.


Asunto(s)
Calcio , Humanos , Calcio/química , Calsecuestrina/química , Calsecuestrina/genética , Calsecuestrina/metabolismo , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/aislamiento & purificación , Estabilidad Proteica , Animales , Células CHO , Cricetulus , Precipitación Química
7.
Toxics ; 12(6)2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38922087

RESUMEN

Pyroptosis represents a type of cell death mechanism notable for its cell membrane disruption and the subsequent release of proinflammatory cytokines. The Nod-like receptor family pyrin domain containing inflammasome 3 (NLRP3) plays a critical role in the pyroptosis mechanism associated with various diseases resulting from particulate matter (PM) exposure. Tert-butylhydroquinone (tBHQ) is a synthetic antioxidant commonly used in a variety of foods and products. The aim of this study is to examine the potential of tBHQ as a therapeutic agent for managing sinonasal diseases induced by PM exposure. The occurrence of NLRP3 inflammasome-dependent pyroptosis in RPMI 2650 cells treated with PM < 4 µm in size was confirmed using Western blot analysis and enzyme-linked immunosorbent assay results for the pyroptosis metabolites IL-1ß and IL-18. In addition, the inhibitory effect of tBHQ on PM-induced pyroptosis was confirmed using Western blot and immunofluorescence techniques. The inhibition of tBHQ-mediated pyroptosis was abolished upon nuclear factor erythroid 2-related factor 2 (Nrf2) knockdown, indicating its involvement in the antioxidant mechanism. tBHQ showed potential as a therapeutic agent for sinonasal diseases induced by PM because NLRP3 inflammasome activation was effectively suppressed via the Nrf2 pathway.

8.
N Z Med J ; 137(1597): 53-66, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38901049

RESUMEN

AIM: There are no data on the performance of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in the staging and diagnosis of lung cancer in New Zealand. We aimed to assess the performance of EBUS-TBNA for lung cancer staging and diagnosis at our institution before and after the commencement of regular performance monitoring with comparison to published EBUS quality indicators. METHODS: The performance of EBUS-TBNA in the staging and diagnosis of lung cancer was assessed in two phases. Phase 1 consisted of a retrospective review of all lung cancer EBUS performed over a 2-year period. Published quality indicators were determined from the literature with relevant indicators being extracted and used to determine EBUS performance. Local reporting and education were undertaken and prospective data collection was commenced. Phase 2 consisted of prospective assessment of all lung cancer EBUS over the subsequent year. Performance of EBUS was then compared between phases 1 and 2 in order to determine the effect of performance monitoring and identify areas for service improvement. RESULTS: A total of 115 staging EBUS and 117 diagnostic EBUS were performed during the study period. Staging EBUS demonstrated good performance across phases 1 and 2 with high sensitivity and negative predictive values (NPV) for the detection of N2/3 disease, meeting published quality standards. During phase 2 there was evidence of a transition towards more guideline-concordant practice evidenced by more detailed nodal sampling during staging EBUS; however, this did not affect overall sensitivity or NPV. Diagnostic EBUS resulted in high rates of pathological confirmation meeting published quality standards across both phases. Pathway times were similar between phases 1 and 2, with reporting of molecular profiling being the predominant factor in delayed pathway times. CONCLUSION: Monitoring and reporting of local performance allows critical assessment of practice and can identify areas for quality improvement. This review demonstrated good overall performance but prompted a move towards more guideline-concordant practice with increased mediastinal nodal sampling during staging procedures. Consideration should be given to the adoption of routine EBUS performance monitoring within local and/or regional networks, which could be incorporated alongside the newly proposed Lung Cancer Clinical Quality Registry.


Asunto(s)
Neoplasias Pulmonares , Estadificación de Neoplasias , Indicadores de Calidad de la Atención de Salud , Humanos , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/diagnóstico por imagen , Nueva Zelanda , Masculino , Femenino , Estudios Retrospectivos , Anciano , Persona de Mediana Edad , Biopsia por Aspiración con Aguja Fina Guiada por Ultrasonido Endoscópico/normas , Biopsia por Aspiración con Aguja Fina Guiada por Ultrasonido Endoscópico/métodos , Estudios Prospectivos , Broncoscopía/métodos , Anciano de 80 o más Años , Endosonografía/métodos , Endosonografía/normas , Adulto
9.
Clin Orthop Surg ; 16(3): 470-476, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38827753

RESUMEN

Background: This study aims to report the midterm outcomes after surgical treatment of Hawkins Classification III Talar neck fractures. Methods: From March 2010 to April 2022, among a total of 155 patients who visited our hospital with talus fractures, 31 patients underwent surgical treatment for Hawkins classification III talar neck fractures. The inclusion criteria comprised patients with a symptom duration of over 1 year who were available for outpatient follow-up and underwent magnetic resonance imaging (MRI) follow-up 2 months after surgery. Exclusion criteria included patients without preoperative ankle periarticular arthritis, and a total of 27 patients were enrolled. Traffic accidents and falls accounted for 86% of 23 cases, open fractures were 8 cases, and the mean follow-up period was 34.10 months (range, 12-80 months). Clinical outcomes were measured by American Orthopaedic Foot and Ankle Society (AOFAS) score and Foot function index (FFI), and radiological results were obtained using simple radiographs before and after surgery and MRI at 2 months postoperatively to confirm bone union and complications. Results: Complete bone union was achieved in all cases, and the mean duration of union was 4.9 months (range, 4-6 months) and there were no nonunion and varus malunion. At the final follow-up, the mean AOFAS score was 80.18 points (range, 36-90 points) and the mean FFI score was 31.43 points (range, 10-68 points), showing relatively good clinical outcomes. There were 15 cases of avascular necrosis, 6 cases of traumatic arthritis of the ankle joint, 6 cases of irritation of the posterior tibial nerve, and 4 cases of wound problems. Conclusions: Hawkins classification III talar neck fractures are mostly caused by high-energy injuries and have a relatively poor prognosis due to the high incidence of complications such as avascular necrosis or posttraumatic arthritis. However, if correct anatomical reduction and rigid internal fixation are performed within a short time after the injury, good results can be expected.


Asunto(s)
Fijación Interna de Fracturas , Fracturas Óseas , Astrágalo , Humanos , Astrágalo/cirugía , Astrágalo/lesiones , Astrágalo/diagnóstico por imagen , Masculino , Femenino , Adulto , Persona de Mediana Edad , Fijación Interna de Fracturas/métodos , Fracturas Óseas/cirugía , Fracturas Óseas/diagnóstico por imagen , Adulto Joven , Anciano , Estudios Retrospectivos , Resultado del Tratamiento , Adolescente , Imagen por Resonancia Magnética
10.
Nanomaterials (Basel) ; 14(9)2024 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-38727351

RESUMEN

We developed a novel electrochemical sensor for the detection of alfuzosin (AFZ), a drug used to treat benign prostatic hyperplasia, using a double-shelled Co3O4/NiCo2O4 nanocomposite-modified electrode. The nanocomposites were synthesized using a template-assisted approach, with zeolitic imidazole framework-67 (ZIF-67) as the sacrificial template, involving the formation of uniform ZIF-67/Ni-Co layered double hydroxide (LDH) hollow structures followed by calcination to achieve the final nanocomposite. The nanocomposite was characterized by various techniques and showed high porosity, large surface area, and good conductivity. The nanocomposite-modified electrode exhibited excellent electrocatalytic activity towards AFZ oxidation, with a wide linear range of 5-180 µM and a low limit of detection of 1.37 µM. The sensor also demonstrated good repeatability, reproducibility, and stability selectivity in the presence of common interfering substances. The sensor was successfully applied to determine the AFZ in pharmaceutical tablets and human serum samples, with satisfactory recoveries. Our results suggest that the double-shelled Co3O4/NiCo2O4 nanocomposite is a promising material for the fabrication of electrochemical sensors for AFZ detection.

11.
Sci Rep ; 14(1): 7623, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38561385

RESUMEN

In this paper, high-performance indium gallium oxide (IGO) thin-film transistor (TFT) with a double-gate (DG) structure was developed using an atomic layer deposition route. The device consisting of 10-nm-thick IGO channel and 2/48-nm-thick SiO2/HfO2 dielectric was designed to be suitable for a display backplane in augmented and virtual reality applications. The fabricated DG TFTs exhibit outstanding device performances with field-effect mobility (µFE) of 65.1 ± 2.3 cm2V-1 s-1, subthreshold swing of 65 ± 1 mVdec-1, and threshold voltage (VTH) of 0.42 ± 0.05 V. Both the (µFE) and SS are considerably improved by more than two-fold in the DG IGO TFTs compared to single-gate (SG) IGO TFTs. Important finding was that the DG mode of IGO TFTs exhibits the nearly temperature independent µFE variations in contrast to the SG mode which suffers from the severe remote Coulomb scattering. The rationale for this disparity is discussed in detail based on the potential distribution along the vertical direction using technology computer-aided design simulation. Furthermore, the DG IGO TFTs exhibit a greatly improved reliability with negligible VTH shift of - 0.22 V under a harsh negative bias thermal and illumination stress condition with an electric field of - 2 MVcm-1 and blue light illumination at 80 °C for 3600 s. It could be attributed to the increased electrostatic potential that results in fast re-trapping of the electrons generated by the light-induced ionization of deep level oxygen vacancy defects.

12.
J Hazard Mater ; 469: 133955, 2024 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-38457976

RESUMEN

The complexity around the dynamic markets for new psychoactive substances (NPS) forces researchers to develop and apply innovative analytical strategies to detect and identify them in influent urban wastewater. In this work a comprehensive suspect screening workflow following liquid chromatography - high resolution mass spectrometry analysis was established utilising the open-source InSpectra data processing platform and the HighResNPS library. In total, 278 urban influent wastewater samples from 47 sites in 16 countries were collected to investigate the presence of NPS and other drugs of abuse. A total of 50 compounds were detected in samples from at least one site. Most compounds found were prescription drugs such as gabapentin (detection frequency 79%), codeine (40%) and pregabalin (15%). However, cocaine was the most found illicit drug (83%), in all countries where samples were collected apart from the Republic of Korea and China. Eight NPS were also identified with this protocol: 3-methylmethcathinone 11%), eutylone (6%), etizolam (2%), 3-chloromethcathinone (4%), mitragynine (6%), phenibut (2%), 25I-NBOH (2%) and trimethoxyamphetamine (2%). The latter three have not previously been reported in municipal wastewater samples. The workflow employed allowed the prioritisation of features to be further investigated, reducing processing time and gaining in confidence in their identification.


Asunto(s)
Drogas Ilícitas , Contaminantes Químicos del Agua , Aguas Residuales , Flujo de Trabajo , Psicotrópicos , China , Contaminantes Químicos del Agua/análisis
13.
Sci Total Environ ; 926: 171753, 2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38522552

RESUMEN

Removing perfluoro(2-methyl-3-oxahexanoic) acid (HFPO-DA) in water treatment is hindered by its hydrophobicity and negative charge. Two adsorbents, quaternary-ammonium-functionalized silica gel (Qgel), specifically designed for anionic hydrophobic compounds, and conventional granular activated carbon (GAC) were investigated for HFPO-DA removal. ANOVA results (p â‰ª 0.001) revealed significant effects on initial concentration, contact time, and adsorbent type. Langmuir model-derived capacities were 285.019 and 144.461 mg/g for Qgel and GAC, respectively, with Qgel exhibiting higher capacity irrespective of pH. In column experiments, selective removal of HFPO-DA removal with Qgel was observed; specifically, in the presence of NaCl, the breakthrough time was extended by 10 h from 26 to 36 h. Meanwhile, the addition of NaCl decreased the breakthrough time from 32 to 14 h for GAC. However, in the presence of carbamazepine, neither of the adsorbents significantly changed the breakthrough time for HFPO-DA. Molecular simulations were also used to compare the adsorption energies and determine the preferential interactions of HFPO-DA and salts or other chemicals with Qgel and GAC. Molecular simulations compared adsorption energies, revealing preferential interactions with Qgel and GAC. Notably, HFPO-DA adsorption energy on GAC surpassed other ions during coexistence. Specifically, with Cl- concentrations from 1 to 10 times, Qgel showed lower adsorption energy for HFPO-DA (-62.50 ± 5.44 eV) than Cl- (-52.89 ± 2.59 eV), a significant difference (p = 0.036). Conversely, GAC exhibited comparable or higher adsorption energy for HFPO-DA (-18.33 ± 40.38 eV) than Cl- (-32.36 ± 29.89 eV), with no significant difference (p = 0.175). This suggests heightened selectivity of Qgel for HFPO-DA removal compared to GAC. Consequently, our study positions Qgel as a promising alternative for effective HFPO-DA removal, contributing uniquely to the field. Additionally, our exploration of molecular simulations in predicting micropollutant removal adds novelty to our study.

14.
Methods Mol Biol ; 2755: 227-247, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38319582

RESUMEN

Hypoxia is a common and critical feature of solid tumors that contributes to the plasticity and heterogeneity of the cancer cells. Cancer cell populations take on a region-specific adaptation induced by hypoxia, and each cancer cell population will show different levels of sensitivity and resistance to cancer therapeutics. Therefore, a faithful recapitulation of tumor hypoxia that allows for accurate assessments of hypoxia-induced adaptations, heterogeneity, and response to therapy is needed to develop new therapeutic approaches. The existing hypoxic tumor models rely on complex fabrication methods and external gas sources that make them unfavorable for the early-stage screening of new therapeutics. Here, we demonstrate how to establish a cleanroom-free microfluidic device that supports both 2D and 3D hypoxic tumor modeling through natural cancer cell metabolism and confirm the induction of the hypoxic gradient.


Asunto(s)
Hipoxia , Neoplasias , Humanos , Dispositivos Laboratorio en un Chip , Hipoxia Tumoral
15.
J Hazard Mater ; 467: 133629, 2024 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-38340559

RESUMEN

This study compared target/suspect/nontarget analysis via liquid chromatography-high-resolution mass spectrometry (LC-HRMS) with traditional environmental forensic methods, specifically nitrate and its stable N isotope, in assessing groundwater pollution from livestock manure and agriculture. Using an in-house database of 1471 target and suspects, 35 contaminants (pesticides, veterinary drugs, surfactants) were identified, some uniquely linked to specific pollution sources, such as sulfamethazine and 4-formylaminoantipyrine in manure-affected areas. Pesticides were widespread, typically showing higher intensity in agricultural zones. On the other hand, the results of stable N isotope analysis (δ15N-NO3: 4.8 to 16.4‰) indicated the influence of human activities such as fertilizers, sewage, and manure in all sampling sites, including the control site far from the pollution sources and cannot differentiate the specific sources. The study underscores LC-HRMS's efficacy in different pollution sources, surpassing the limitations of stable N isotope analysis, and provides valuable insights for polluted groundwater source tracking strategies.

16.
ACS Appl Mater Interfaces ; 16(7): 9020-9029, 2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38324755

RESUMEN

Despite the considerable potential of AlGaN-based ultraviolet-B light-emitting diodes (UV-B LEDs) in various applications such as phototherapy, UV curing, plant growth, and analytical technology, their development is still ongoing due to low luminescence efficiency. In this study, we introduced a novel epitaxial growth mechanism to effectively control the height and thickness of AlGaN multiple wells (MWs) on AlGaN nanorod structures using horizontal reactor-based metal-organic chemical vapor deposition (MOCVD). By adjusting the H2 carrier gas flow rate, we could control the growth boundary layer's thickness, successfully separating the AlGaN well and p-AlGaN layer from the substrate. Cathodoluminescence (CL) measurements confirmed the stability of the core-shell AlGaN quantum wells as a highly stable nonpolarized structure, with the wavelength peak remaining almost unchanged under various injection currents. Furthermore, transmission electron microscopy (TEM) provided clear evidence of differentiation, highlighting the distinct formation of the 275 nm AlGaN core and the 295 nm AlGaN shell structure. The developed AlGaN MW structure, characterized by these rectification features, not only demonstrated a significantly improved electroluminescence (EL) peak intensity but also exhibited a much lower leakage current compared to the conventional core-shell AlGaN structure. The newly proposed growth mechanism and advanced nonpolarized core-shell AlGaN structure are expected to serve as excellent alternatives for substantially enhancing the efficiency of the next generation of high-efficiency UV LEDs.

17.
J Biol Chem ; 300(3): 105764, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38367670

RESUMEN

In Mycobacterium smegmatis, the transcriptional activity of the alternative sigma factor SigF is posttranslationally regulated by the partner switching system consisting of SigF, the anti-SigF RsbW1, and three anti-SigF antagonists (RsfA, RsfB, and RsbW3). We previously demonstrated that expression of the SigF regulon is strongly induced in the Δaa3 mutant of M. smegmatis lacking the aa3 cytochrome c oxidase, the major terminal oxidase in the respiratory electron transport chain. Here, we identified and characterized the RsfSR two-component system involved in regulating the phosphorylation state of the major anti-SigF antagonist RsfB. RsfS (MSMEG_6130) is a histidine kinase with the cyclase/histidine kinase-associated sensing extracellular 3 domain at its N terminus, and RsfR (MSMEG_6131) is a receiver domain-containing protein phosphatase 2C-type phosphatase that can dephosphorylate phosphorylated RsfB. We demonstrated that phosphorylation of RsfR on Asp74 by RsfS reduces the phosphatase activity of RsfR toward phosphorylated RsfB and that the cellular abundance of the active unphosphorylated RsfB is increased in the Δaa3 mutant relative to the WT strain. We also demonstrated that the RsfSR two-component system is required for induction of the SigF regulon under respiration-inhibitory conditions such as inactivation of the cytochrome bcc1 complex and aa3 cytochrome c oxidase, as well as hypoxia, electron donor-limiting, high ionic strength, and low pH conditions. Collectively, our results reveal a key regulatory element involved in regulating the SigF signaling system by monitoring the state of the respiratory electron transport chain.


Asunto(s)
Proteínas Bacterianas , Complejo IV de Transporte de Electrones , Mycobacterium smegmatis , Factor sigma , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Transporte de Electrón , Complejo IV de Transporte de Electrones/genética , Complejo IV de Transporte de Electrones/metabolismo , Regulación Bacteriana de la Expresión Génica , Histidina Quinasa/genética , Histidina Quinasa/metabolismo , Mycobacterium smegmatis/enzimología , Mycobacterium smegmatis/genética , Monoéster Fosfórico Hidrolasas/metabolismo , Factor sigma/genética , Factor sigma/metabolismo
18.
Chemosphere ; 353: 141429, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38364917

RESUMEN

Polycyclic aromatic hydrocarbons (PAHs) comprise a group of compounds resulting from the incomplete combustion of organic matter. Firefighters engaged in fire suppression are highly exposed to PAHs. This study centered on evaluating the exposure levels and health risks of PAHs in South Korean firefighters involved in firefighting activities. The concentrations of 10 PAH metabolites in the urine of firefighters were measured immediately after, and two weeks post their engagement in extinguishing a large tire factory fire. The levels of OH-PAHs in urine samples immediately after fire suppression were elevated by a factor of 1.01-1.84 compared to urine samples from non-exposed period. The median concentration of total PAH metabolites (OH-PAHs) was higher in urine samples immediately after fire suppression (5910 ng/g creatinine) than in urine samples from non-exposed periods (5020 ng/g creatinine). However, the ∑OH-PAH levels in firefighters' urine were related to personal habits such as smoking. The concentrations of all individual OH-PAHs in the urine samples of nonsmokers exhibited a substantial increase, ranging from 1.37 to 2.3 times, clearly demonstrating that firefighting activities were a substantial source of PAH exposure. The calculated values associated with the health risks stemming from exposure to PAHs, including carcinogenic risk, total estimated daily intake (TEDI), and hazard quotients/index (HQs/HI), all fell within acceptable limits, indicating negligible risk. However, the HQ/HI values and TEDI for individual and total PAH exposures, except those for naphthalene, were 1.36-2.00 times higher in firefighters' samples taken after firefighting operations compared to those during regular duty. This underscores the need for more comprehensive investigations to comprehend the singular impact of firefighting activities due to the diverse sources of PAH emissions in the environment.


Asunto(s)
Contaminantes Ocupacionales del Aire , Bomberos , Exposición Profesional , Hidrocarburos Policíclicos Aromáticos , Humanos , Contaminantes Ocupacionales del Aire/análisis , Exposición Profesional/análisis , Creatinina , Monitoreo del Ambiente/métodos , Hidrocarburos Policíclicos Aromáticos/análisis
19.
Exp Mol Med ; 56(2): 319-328, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38355825

RESUMEN

DNA damage is a critical threat that poses significant challenges to all cells. To address this issue, cells have evolved a sophisticated molecular and cellular process known as the DNA damage response (DDR). Among the various cell types, mammalian oocytes, which remain dormant in the ovary for extended periods, are particularly susceptible to DNA damage. The occurrence of DNA damage in oocytes can result in genetic abnormalities, potentially leading to infertility, birth defects, and even abortion. Therefore, understanding how oocytes detect and repair DNA damage is of paramount importance in maintaining oocyte quality and preserving fertility. Although the fundamental concept of the DDR is conserved across various cell types, an emerging body of evidence reveals striking distinctions in the DDR between mammalian oocytes and somatic cells. In this review, we highlight the distinctive characteristics of the DDR in oocytes and discuss the clinical implications of DNA damage in oocytes.


Asunto(s)
Reparación del ADN , Oocitos , Animales , Femenino , Embarazo , Oocitos/metabolismo , Ovario , Daño del ADN , Mamíferos
20.
Chemosphere ; 352: 141275, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38253089

RESUMEN

Priority water pollutants comprising six plasticizers, 18 volatile organic compounds (VOCs), total petroleum hydrocarbon (TPH), 1,4-dioxane, epichlorohydrin, formaldehyde, acrylamide, and cyanides were determined in surface river sediments to assess their distribution patterns and ecological risks. Among these, di (2-ethylhexyl) phthalate (DEHP), toluene, TPH, and acrylamide were frequently found in sediments. The industrial sites had higher concentrations of ∑plasticizers (median 628 ng/g dry weight (dw)), ∑VOCs (median 3.35 ng/g dw), acrylamide (median 0.966 ng/g dw), and TPH (median 152 µg/g dw) in sediments than the mixed and non-industrial areas. The other pollutants did not show the significant differences in levels according to site types because of their relatively low detection frequencies. Volatile and soluble substances as well as hydrophobic pollutants were predominantly detected in surface sediments from industrial areas. Sediment contamination patterns were affected by the size and composition of the industrial zones around the sampling sites. The ecological risks determined using the sediment quality guidelines (DEHP, VOCs, and TPH) and the mean probable effect level quotients (DEHP) were mostly acceptable. However, the two most representative industrial regions (the largest industrial area and the first industrial city) showed risks of concern for DEHP and TPH.


Asunto(s)
Dietilhexil Ftalato , Contaminantes Ambientales , Petróleo , Ácidos Ftálicos , Contaminantes Químicos del Agua , Contaminantes del Agua , Ríos/química , Contaminantes Químicos del Agua/análisis , Medición de Riesgo , Plastificantes , Sedimentos Geológicos/química , Acrilamidas , China , Monitoreo del Ambiente
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