The 2023 MDPI Annual Report has
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18 pages, 8350 KiB  
Article
Spacing Ratio Effects on the Evolution of the Flow Structure of Two Tandem Circular Cylinders in Proximity to a Wall
by Xiang Qiu, Xuezhi Ji, Jiankang Zhou, Jiahua Li, Yizhou Tao and Yulu Liu
J. Mar. Sci. Eng. 2024, 12(5), 721; https://doi.org/10.3390/jmse12050721 (registering DOI) - 26 Apr 2024
Abstract
The flow around two tandem circular cylinders in proximity to a wall is investigated using particle image velocimetry (PIV) for Re = 2 × 103. The spacing ratios L/D are 1, 2, and 5, and the gap ratios G [...] Read more.
The flow around two tandem circular cylinders in proximity to a wall is investigated using particle image velocimetry (PIV) for Re = 2 × 103. The spacing ratios L/D are 1, 2, and 5, and the gap ratios G/D are 0.3, 0.6, and 1. The proper orthogonal decomposition (POD) method and λci vortex identification method are used to investigate the evolution of flow structure, and the influences of L/D and G/D on flow physics are shown. At L/D = 2 and G/D = 0.3, a “pairing” process occurs between the wall shear layer and the upstream cylinder’s lower shear layer, resulting in a small separation bubble behind the upstream cylinder. At L/D = 1, the Strouhal number (St) increases with decreasing G/D. At three gap ratios, the St gradually decreases as L/D increases. At G/D = 0.3, there is nearly a 49.98% decrease from St = 0.3295 at L/D = 1 to St = 0.1648 at L/D = 5, which is larger than the reductions in cases of G/D = 0.6 and G/D = 1. The effects of L/D on the evolution of flow structure at G/D = 0.6 are revealed in detail. At L/D = 1, the vortex shedding resembles that of the single cylinder. As L/D increases to 2, a squarish flow structure is formed between two cylinders, and a small secondary vortex is formed due to induction of the lower shear layer of the upstream cylinder. At L/D = 5, there is a vortex merging process between the upper wake vortices of the upstream and downstream cylinders, and the lower wake vortex of the upstream cylinder directly impinges the downstream cylinder. In addition, the shear layers and wake vortices of the upstream cylinder interact with the wake of the downstream cylinder as L/D increases, resulting in reductions in velocity fluctuations, and the production and turbulent diffusion of turbulent kinetic energy are decreased behind the downstream cylinder. Full article
(This article belongs to the Section Ocean Engineering)
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25 pages, 6226 KiB  
Article
RisDes_Index: An Index for Analysing the Advance of Areas Undergoing Desertification Using Satellite Data
by Thieres George Freire da Silva, José Francisco da Cruz Neto, Alexandre Maniçoba da Rosa Ferraz Jardim, Carlos André Alves de Souza, George do Nascimento Araújo Júnior, Marcos Vinícius da Silva, Jhon Lennon Bezerra da Silva, Ailton Alves de Carvalho, Abelardo Antônio de Assunção Montenegro and Luciana Sandra Bastos de Souza
AgriEngineering 2024, 6(2), 1150-1174; https://doi.org/10.3390/agriengineering6020066 (registering DOI) - 26 Apr 2024
Abstract
The proposal for a method of identifying the occurrence of desertification that has a strong association with in situ data leads to more assertive results when analysing the contribution of climate and social and economic factors to advancing the process. This study aimed [...] Read more.
The proposal for a method of identifying the occurrence of desertification that has a strong association with in situ data leads to more assertive results when analysing the contribution of climate and social and economic factors to advancing the process. This study aimed to develop a methodology called the RisDes_Index to evaluate the evolution of the desertification process based on satellite data. The concept of the RisDes_Index method was based on the reflectance variables of the R, B and G bands, albedo and LAI of the Landsat 5/TM and Landsat 8/OLI satellites. Principal component analysis was used to assess the biophysical basis of the RisDes_Index by associating the results with micrometeorological data, physical and chemical properties, and vegetation cover data collected from five experimental sites in the semi-arid region of Brazil. These sites included one from a seasonally dry forest (i.e., the Caatinga), an agricultural cactus plantation, an area undergoing desertification, and two irrigated sugarcane crops (wetlands), one with and one without straw cover. The RisDes_Index was applied to all pixels of the images from 5 December 1991, 14 November 2001, 20 November 2009 and 6 October 2016 of an important desertification nucleus (DN) in the semi-arid region of Brazil, i.e., the DN of Cabrobó. The proposed RisDes_Index was able to identify areas with significant processes of desertification, which mainly occur in areas of sandy, acidic, bare soils with a high β value (Bowen ratio) and high soil temperature. The results of the RisDes_Index showed that in 5 December 1991, desertified areas comprised 38% of the total area of the DN of Cabrobó, expanding to 51% in 2016. Application of the RisDes_Index confirmed the advance of desertification in the DN of Cabrobó. This was due to a consequent increase in the water deficit and intensified deforestation to increase the areas of livestock farming. The RisDes_Index proved to be a robust method, as its estimation based on simple satellite products exhibited a strong association with biophysical variables of areas with different land uses and degradation levels. Thus, it is suggested that the RisDes_Index be applied in various regions of the world, with the idea of directing action to meet the advance of desertification. Full article
(This article belongs to the Section Remote Sensing in Agriculture)
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15 pages, 5679 KiB  
Article
Consecutive Pruning Enhances Leaf Flavonoids, Leaf Yield, and Cutting Rooting in Ginkgo biloba
by Lei Zhong, Shiyuan Xu, Shuwen Xu, Wanxiang Zhou, Zhaogeng Lu, Biao Jin and Li Wang
Forests 2024, 15(5), 761; https://doi.org/10.3390/f15050761 (registering DOI) - 26 Apr 2024
Abstract
Ginkgo biloba L. is a valuable medicinal plant known for its high content of flavonoids and terpenoids in the leaves of young trees. Pruning can increase leaf yield in ginkgo plantations; however, it is unclear how the intensity of pruning affects leaf yield [...] Read more.
Ginkgo biloba L. is a valuable medicinal plant known for its high content of flavonoids and terpenoids in the leaves of young trees. Pruning can increase leaf yield in ginkgo plantations; however, it is unclear how the intensity of pruning affects leaf yield and quality. In addition, G. biloba exhibits low cutting rooting rates, which limits its efficiency in asexual propagation. In our study, we compared consecutive pruning with varying levels of intensity, including top pruning, light pruning, and heavy pruning, to evaluate the effects of pruning on leaf yield and cutting rooting. The results showed that these three pruning methods all contributed to an increase in the number of new branches, the leaf weight, and the flavonoid content in five-year-old trees. Among them, the effect of light pruning was the best, with a 150% increase in branch number, a 130% increase in leaf weight, and a 40.6% increase in flavonoid content. The secondary pruning further increased leaf area by 22.3%, indicating that secondary pruning further enhanced the rejuvenation of plants and increased leaf yield. At the transcriptional level, pruning can significantly change the expression of genes related to bud sprouting, resulting in a particularly significant increase in SHR expression in the buds. Pruning also promoted the expression of important genes related to flavonoid synthesis, including chalcone synthase (CHS), flavonoid 3′-hydroxylase (F3′H), flavonol synthase (FLS), and dihydroflavonol reductase (DFR). Furthermore, we demonstrated a significant increase in the rooting rate of these second-pruned branch cuttings and screened the optimal hormone ratio for rooting, which is 1.5 μM MeJA + 400 mg/L NAA + 100 mg/L Uniconazole-P. These results suggest that secondary pruning can effectively rejuvenate plants to promote cutting rooting in G. biloba. This method can not only be used to improve the yield and quality of ginkgo leaves, but also for cutting propagation. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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18 pages, 1169 KiB  
Systematic Review
The Effect of Extremely Low-Frequency Magnetic Field on Stroke Patients: A Systematic Review
by Renata Marchewka, Tomasz Trzmiel and Katarzyna Hojan
Brain Sci. 2024, 14(5), 430; https://doi.org/10.3390/brainsci14050430 (registering DOI) - 26 Apr 2024
Abstract
Background: The aim of this study was to review the current state of scientific evidence on the effect of extremely low-frequency magnetic fields stimulation (ELF-MFs) on stroke patients. Methods: A systematic review of PubMed, ScienceDirect, PeDro and Embase databases was conducted. Only articles [...] Read more.
Background: The aim of this study was to review the current state of scientific evidence on the effect of extremely low-frequency magnetic fields stimulation (ELF-MFs) on stroke patients. Methods: A systematic review of PubMed, ScienceDirect, PeDro and Embase databases was conducted. Only articles published in English, involving adult participants and focusing on individuals who had experienced a stroke, specifically examining the impact of ELF-MFs on post-stroke patients and had well-defined criteria for inclusion and exclusion of participants, were included. The methodological quality of the included studies was assessed using the Quality Assessment Tool for Quantitative Studies (QATQS). Results: A total of 71 studies were identified through database and reference lists’ search, from which 9 were included in the final synthesis. All included studies showed a beneficial effect of ELF-MFs on stroke patients, however seven of the included studies were carried by the same research group. Improvements were observed in domains such as oxidative stress, inflammation, ischemic lesion size, functional status, depressive symptoms and cognitive abilities. Conclusions: The available literature suggests a beneficial effect of ELF-MFs on post-stroke patients; however, the current data are too limited to broadly recommend the use of this method. Further research with improved methodological quality is necessary. Full article
(This article belongs to the Special Issue Stroke and Acute Stroke Care: Looking Ahead)
24 pages, 1116 KiB  
Article
How to Create Healthy, Stress-Resilient Post-Pandemic Cities
by Magdalena Wdowicka, Lidia Mierzejewska, Marta Szejnfeld, Bogusz Modrzewski, Kamila Sikorska-Podyma, Adam Wronkowski and Ewa Lechowska
Sustainability 2024, 16(9), 3644; https://doi.org/10.3390/su16093644 (registering DOI) - 26 Apr 2024
Abstract
This article analyzes the correlation between the city size, population density and character of three Polish cities and the following aspects: (1) inhabitants’ subjective stress level and its change during the COVID-19 pandemic, (2) sources and effects of their stress during the pandemic, [...] Read more.
This article analyzes the correlation between the city size, population density and character of three Polish cities and the following aspects: (1) inhabitants’ subjective stress level and its change during the COVID-19 pandemic, (2) sources and effects of their stress during the pandemic, (3) ways of reducing stress by residents and the role of greenery in this respect and (4) directions of changes in the structure of post-pandemic cities desired by their residents. The main research method was geo-surveys, the results of which were developed using statistical analysis and GIS methods. On the basis of the constructed scale, respondents subjectively assessed the level of experienced stress and its change during the COVID-19 pandemic. The research shows that none of the considered features of cities (including size measured by the number of inhabitants) are related to the level of pandemic stress of their inhabitants. All of them, on the other hand, are correlated with the directions of urban spatial development desired by the residents, conducive to stress reduction. Furthermore, the size of the city and its character affect the subjectively perceived change in stress levels during the pandemic (compared to the stress level before pandemic). Some of the effects of pandemic stress and ways of reducing it depend on the character of the city. The stress experienced by the inhabitants is the lowest in cities with the largest share of green areas in the spatial structure (especially with forest complexes and naturally shaped areas of river valleys), where an effective system of greenery has been adopted (the Howard’s garden city model), and at the same time with dominant single-family housing. The research results were used to indicate new directions for shaping post-pandemic cities that are more resistant to stress and thus healthier for their residents. Full article
20 pages, 2280 KiB  
Article
Revealing Genetic Dynamics: scRNA-seq Unravels Modifications in Human PDL Cells across In Vivo and In Vitro Environments
by Ali T. Abdallah, Michael Peitz and Anna Konermann
Int. J. Mol. Sci. 2024, 25(9), 4731; https://doi.org/10.3390/ijms25094731 (registering DOI) - 26 Apr 2024
Abstract
 The periodontal ligament (PDL) is a highly specialized fibrous tissue comprising heterogeneous cell populations of an intricate nature. These complexities, along with challenges due to cell culture, impede a comprehensive understanding of periodontal pathophysiology. This study aims to address this gap, employing [...] Read more.
 The periodontal ligament (PDL) is a highly specialized fibrous tissue comprising heterogeneous cell populations of an intricate nature. These complexities, along with challenges due to cell culture, impede a comprehensive understanding of periodontal pathophysiology. This study aims to address this gap, employing single-cell RNA sequencing (scRNA-seq) technology to analyze the genetic intricacies of PDL both in vivo and in vitro. Primary human PDL samples (n = 7) were split for direct in vivo analysis and cell culture under serum-containing and serum-free conditions. Cell hashing and sorting, scRNA-seq library preparation using the 10x Genomics protocol, and Illumina sequencing were conducted. Primary analysis was performed using Cellranger, with downstream analysis via the R packages Seurat and SCORPIUS. Seven distinct PDL cell clusters were identified comprising different cellular subsets, each characterized by unique genetic profiles, with some showing donor-specific patterns in representation and distribution. Formation of these cellular clusters was influenced by culture conditions, particularly serum presence. Furthermore, certain cell populations were found to be inherent to the PDL tissue, while others exhibited variability across donors. This study elucidates specific genes and cell clusters within the PDL, revealing both inherent and context-driven subpopulations. The impact of culture conditions—notably the presence of serum—on cell cluster formation highlights the critical need for refining culture protocols, as comprehending these influences can drive the creation of superior culture systems vital for advancing research in PDL biology and regenerative therapies. These discoveries not only deepen our comprehension of PDL biology but also open avenues for future investigations into uncovering underlying mechanisms.  Full article
(This article belongs to the Special Issue Cutting-Edge Insights into Oral Health and Disease)
21 pages, 9417 KiB  
Article
Linking the Evolution of the Andalién River Morphology (Central–Southern Chile) to Anthropogenic Interventions by Using a New QGIS Tool
by Andrea Gianni Cristoforo Nardini, Constanza Gonzalez, Angela Contreras, Germán Velásquez, José Vargas-Baecheler, Hervé Piégay, Joaquin Espinoza and Santiago Yépez
Sustainability 2024, 16(9), 3642; https://doi.org/10.3390/su16093642 (registering DOI) - 26 Apr 2024
Abstract
In recent decades, the interplay of several factors, including land use change (particularly urbanization) and global warming, has resulted in harsher flooding, often associated with geomorphic disruption. These events in Latin America are predominantly driven by the El Niño Southern Oscillation (ENSO) phenomenon. [...] Read more.
In recent decades, the interplay of several factors, including land use change (particularly urbanization) and global warming, has resulted in harsher flooding, often associated with geomorphic disruption. These events in Latin America are predominantly driven by the El Niño Southern Oscillation (ENSO) phenomenon. The Andalién River basin is no exception, with a notable incident occurring in July 2006. This reality points out the need to study the geomorphological behavior of rivers. Geomatic tools can contribute to address this issue, thereby improving the planning and management of water courses. This paper presents the assessment of the morphological evolution of the Andalién River, downstream to the city of Concepción in a period of 75 years (1945–2020), in response to changes in land use and anthropogenic interventions on the river itself. Based on temporal satellite imagery and historical aerial images (from 1945 to 2020) combined with digital elevation models (LiDAR and TamDEM-X data), morphological alterations are revealed, which were caused by urbanization and anthropogenic activities. We demonstrate how the South River Toolbox (SRT), an original GIS tool developing in QGIS (in-house), enables the extraction of key geomorphological features of a river and their analysis, including their time evolution. This retrospective analysis includes an innovative method and tool to measure the lateral migration rate of the active channel. Ultimately, this study provides valuable insights for future management strategies, offering a comprehensive basin-level analysis of the Andalién River and a cartographic framework to aid decision-making, planning, and management of the fluvial corridor. Full article
15 pages, 784 KiB  
Article
Institutional Surgical Setting and Volume Effects of Certified Arthroplasty Centers in Germany: Evaluation of the Quality of Care in a 5-Year Comparison
by Katrin Osmanski-Zenk, Annett Klinder, Andreas Pingsmann, Christoph H. Lohmann, Hermann Josef Bail, Bernd Kladny and Wolfram Mittelmeier
Healthcare 2024, 12(9), 904; https://doi.org/10.3390/healthcare12090904 (registering DOI) - 26 Apr 2024
Abstract
To improve arthroplasty care quality, the EndoCert initiative focuses on structural, processual, and surgeon-related quality assurance. The aim of this study was to assess the impact of a surgeon’s case load in certified centers on quality of care, distinguished by different types of [...] Read more.
To improve arthroplasty care quality, the EndoCert initiative focuses on structural, processual, and surgeon-related quality assurance. The aim of this study was to assess the impact of a surgeon’s case load in certified centers on quality of care, distinguished by different types of surgeons. Data from the annual reports of EndoCert certified centers for the years 2017 to 2021 were analyzed. The study revealed reduced numbers of cases, while the number of surgeons remained constant. Since 2020, the decrease in the average case load per surgeons has become more pronounced. There were also differences between senior (sECrs) and EndoCert-registered surgeons (ECrs). Before the 2020 pandemic, over half of surgeons exceeded minimum annual case requirements, while, afterwards, this number declined, especially for the ECrs. Affiliated surgeons, who are also sECrs or ECrs, performed predominantly lower numbers of arthroplasties. However, a higher percentage of affiliated surgeons in a center correlated with faster surgeries and lower mortality rates. High numbers of arthroplasties per center or surgeon were not necessarily associated with better quality indicators, especially in the knee. While the comprehensive quality standards may offset volume effects, EndoCert should reconsider minimum volume regulations based on surgeon, but also on each joint. Full article
19 pages, 737 KiB  
Article
Machine Learning to Enhance the Detection of Terrorist Financing and Suspicious Transactions in Migrant Remittances
by Stanley Munamato Mbiva and Fabio Mathias Correa
J. Risk Financial Manag. 2024, 17(5), 181; https://doi.org/10.3390/jrfm17050181 (registering DOI) - 26 Apr 2024
Abstract
Migrant remittances have become significant in poverty alleviation and microeconomic development in low-income countries. However, the ease of conducting global migrant remittance transfers has also introduced the risk of misuse by terrorist organizations to quickly move and conceal operational funds, facilitating terrorism financing. [...] Read more.
Migrant remittances have become significant in poverty alleviation and microeconomic development in low-income countries. However, the ease of conducting global migrant remittance transfers has also introduced the risk of misuse by terrorist organizations to quickly move and conceal operational funds, facilitating terrorism financing. This study aims to develop an unsupervised machine learning algorithm capable of detecting suspicious financial transactions associated with terrorist financing in migrant remittances. To achieve this goal, a structural equation model (SEM) and an outlier detection algorithm were developed to analyze and identify suspicious transactions among the financial activities of migrants residing in Belgium. The results show that the SEM model classifies a significantly high number of transactions as suspicious, making it prone to detecting false positives. Finally, the study developed an ensemble outlier detection algorithm that comprises an isolation forest (IF) and a local outlier factor (LOF) to detect suspicious transactions in the same dataset. The model performed exceptionally well, being able to detect over 90% of suspicious transactions. Full article
(This article belongs to the Section Mathematics and Finance)
16 pages, 850 KiB  
Article
Effects of Commercial Probiotics on the Growth Performance, Intestinal Microbiota and Intestinal Histomorphology of Nile Tilapia (Oreochromis niloticus) Reared in Biofloc Technology (BFT)
by Ayesha Akter Asha, Mohammad Mahfujul Haque, Md. Kabir Hossain, Md. Mahmudul Hasan, Abul Bashar, Md. Zahid Hasan, Mobin Hossain Shohan, Nawshin Nayla Farin, Petra Schneider and Alif Layla Bablee
Biology 2024, 13(5), 299; https://doi.org/10.3390/biology13050299 (registering DOI) - 26 Apr 2024
Abstract
Though different types of commercial probiotics are supplemented in biofloc technology (BFT), very little information is available on their effects on the farmed fish. Therefore, this study focused on evaluating the effects of three most commonly used commercial probiotics on the growth performance, [...] Read more.
Though different types of commercial probiotics are supplemented in biofloc technology (BFT), very little information is available on their effects on the farmed fish. Therefore, this study focused on evaluating the effects of three most commonly used commercial probiotics on the growth performance, intestinal histomorphology, and intestinal microbiota of Nile tilapia (Oreochromis niloticus) reared in BFT. Tilapia fry, with an average weight of 3.02 ± 0.50 g, were stocked at a density of 60 fry/0.2 m3, and cultured for 90 days. Three commercial probiotics were administered, with three replications for each: a single-genus multi-species probiotic (Bacillus spp.) (T1), a multi-genus multi-species probiotic (Bacillus sp., Lactobacillus sp., Nitrosomonas sp., Nitrobacter sp.) (T2), and a multi-species probiotic (Bacillus spp.) combined with enzymes including amylase, protease, cellulase, and xylanase (T3). The results showed significant variations in growth and feed utilization, with T3 outperforming other treatments in terms of weight gain, liver weight, and intestine weight. Adding Bacillus spp. with enzymes (T3) to water significantly increased the histomorphological parameters (villi length, villi depth, crypt depth, muscle thickness, intestinal thickness) as well as microbes (total viable count and total lactic acid bacteria) of intestine of fish compared to T1 and T2, leading to improved digestion and absorption responses. It is concluded that the supplementation of commercial probiotics has potential benefits on farmed fish species in BFT. Full article
(This article belongs to the Special Issue Mechanisms of Immunity and Disease Resistance in Aquatic Animals)
17 pages, 7250 KiB  
Article
Study on the Adaptability Evaluation of Micro-Dispersed-Gel-Strengthened-Alkali-Compound System and the Production Mechanism of Crude Oil
by Teng Wang, Tianjiang Wu, Yunlong Liu, Chen Cheng and Guang Zhao
Processes 2024, 12(5), 871; https://doi.org/10.3390/pr12050871 (registering DOI) - 26 Apr 2024
Abstract
A novel micro-dispersed-gel (MDG)-strengthened-alkali-compound flooding system was proposed for enhanced oil recovery in high-water-cut mature oilfields. Micro-dispersed gel has different adaptability and application schemes with sodium carbonate and sodium hydroxide. The MDG-strengthened-alkali flooding system can reduce the interfacial tension to an ultra-low interfacial-tension [...] Read more.
A novel micro-dispersed-gel (MDG)-strengthened-alkali-compound flooding system was proposed for enhanced oil recovery in high-water-cut mature oilfields. Micro-dispersed gel has different adaptability and application schemes with sodium carbonate and sodium hydroxide. The MDG-strengthened-alkali flooding system can reduce the interfacial tension to an ultra-low interfacial-tension level of 10−2 mN/m, which can reverse the wettability of rock surface. After 30 days aging, the MDG-strengthened-Na2CO3 flooding system has good viscosity retention of 74.5%, with an emulsion stability of 79.13%. The enhanced-oil-recovery ability of the MDG-strengthened-Na2CO3 (MDGSC) flooding system is 43.91%, which is slightly weaker than the 47.78% of the MDG-strengthened-NaOH (MDGSH) flooding system. The crude-oil-production mechanism of the two systems is different, but they all show excellent performance in enhanced oil recovery. The MDGSC flooding system mainly regulates and seals micro-fractures, forcing subsequent injected water to enter the low-permeability area, and it has the ability to wash the remaining oil in micro-fractures. The MDGSH flooding system mainly removes the remaining oil on the rock wall surface in the micro-fractures by efficient washing, and the MDG particles can also form weak plugging of the micro-fractures. The MDG-strengthened-alkali flooding system can be used as an alternative to enhance oil recovery in high-water-cut and highly heterogeneous mature oilfields. Full article
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14 pages, 853 KiB  
Article
Damage Effects and Mechanisms of High-Power Microwaves on Double Heterojunction GaN HEMT
by Zhenyang Ma, Dexu Liu, Shun Yuan, Zhaobin Duan and Zhijun Wu
Aerospace 2024, 11(5), 346; https://doi.org/10.3390/aerospace11050346 (registering DOI) - 26 Apr 2024
Abstract
In this paper, simulation modeling was carried out using Sentaurus Technology Computer-Aided Design. Two types of high electron mobility transistors (HEMT), an AlGaN/GaN/AlGaN double heterojunction and AlGaN/GaN single heterojunction, were designed and compared. The breakdown characteristics and damage mechanisms of the two [...] Read more.
In this paper, simulation modeling was carried out using Sentaurus Technology Computer-Aided Design. Two types of high electron mobility transistors (HEMT), an AlGaN/GaN/AlGaN double heterojunction and AlGaN/GaN single heterojunction, were designed and compared. The breakdown characteristics and damage mechanisms of the two devices under the injection of high-power microwaves (HPM) were studied. The variation in current density and peak temperature inside the device was analyzed. The effect of Al components at different layers of the device on the breakdown of HEMTs is discussed. The effect and law of the power damage threshold versus pulse width when the device was subjected to HPM signals was verified. It was shown that the GaN HEMT was prone to thermal breakdown below the gate, near the carrier channels. A moderate increase in the Al component can effectively increased the breakdown voltage of the device. Compared with the single heterojunction, the double heterojunction HEMT devices were more sensitive to Al components. The high domain-limiting characteristics effectively inhibited the overflow of channel electrons into the buffer layer, which in turn regulated the current density inside the device and improved the temperature distribution. The leakage current was reduced and the device switching characteristics and breakdown voltage were improved. Moreover, the double heterojunction device had little effect on HPM power damage and high damage resistance. Therefore, a theoretical foundation is proposed in this paper, indicating that double heterojunction devices are more stable compared to single heterojunction devices and are more suitable for applications in aviation equipment operating in high-frequency and high-voltage environments. In addition, double heterojunction GaN devices have higher radiation resistance than SiC devices of the same generation. Full article
23 pages, 6786 KiB  
Article
Aboveground Biomass Inversion Based on Object-Oriented Classification and Pearson–mRMR–Machine Learning Model
by Xinyang Chen, Keming Yang, Jun Ma, Kegui Jiang, Xinru Gu and Lishun Peng
Remote Sens. 2024, 16(9), 1537; https://doi.org/10.3390/rs16091537 (registering DOI) - 26 Apr 2024
Abstract
Cities play a crucial role in the carbon cycle. Measuring urban aboveground biomass (AGB) is essential for evaluating carbon sequestration. Satellite remote sensing enables large-scale AGB inversion. However, the apparent differences between forest and grassland biomass pose a significant challenge to the accurate [...] Read more.
Cities play a crucial role in the carbon cycle. Measuring urban aboveground biomass (AGB) is essential for evaluating carbon sequestration. Satellite remote sensing enables large-scale AGB inversion. However, the apparent differences between forest and grassland biomass pose a significant challenge to the accurate estimation of urban AGB using satellite-based data. To address this limitation, this study proposed a novel AGB estimation method using the eastern part of the Zhahe mining area in Huaibei City as the study area, which integrates land cover classification, feature selection, and machine learning modelling to generate high quality biomass maps of different vegetation types in an urban area with complex feature distribution. Utilizing the GEE platform and Sentinel-2 image, we developed an object-oriented machine learning classification algorithm, combining SNIC and GLCM to extract vegetation information. Optimal feature variables for forest and crop-grass AGB inversion were selected using the Pearson–mRMR algorithm. Finally, we constructed nine machine learning models for AGB inversion and selected the model with the highest accuracy to generate the AGB map of the study area. The results of the study are as follows: (1) Compared with the pixel-based classification method, the object-oriented classification method can extract the boundaries of different vegetation types more accurately. (2) Forest AGB is strongly correlated with vegetation indices and physiological parameters, while agri-grass AGB is primarily associated with vegetation indices and vegetation physiological parameters. (3) For forest AGB modelling, the RF-R model outperforms other machine learning models with an R2 of 0.77. For agri-grass AGB modelling, the XGBoost-R model is more accurate, with an R2 of 0.86. (4) The mean forest AGB in the study area was 4.60 kg/m2, while the mean agri-grass AGB was 0.71 kg/m2. High AGB values were predominantly observed in forested areas, which were mainly distributed along roads, waterways, and mountain ranges. Overall, this study contributes to a better understanding of the health of local urban ecosystems and provides valuable insights for ecosystem protection and the sustainable use of natural resources. Full article
(This article belongs to the Section Environmental Remote Sensing)
23 pages, 612 KiB  
Systematic Review
Korean Hospital Nurses’ Experiences with COVID-19: A Meta-Synthesis of Qualitative Findings
by Suk-Jung Han, Hee-Jung Hong and Bok-Soon Shin
Healthcare 2024, 12(9), 903; https://doi.org/10.3390/healthcare12090903 (registering DOI) - 26 Apr 2024
Abstract
During the COVID-19 pandemic, hospital nurses in South Korea cared for patients amid their own anxiety and fear of infection, armed with a sense of professional duty and overcoming all odds to end the country’s infectious disease pandemic. This study aims to provide [...] Read more.
During the COVID-19 pandemic, hospital nurses in South Korea cared for patients amid their own anxiety and fear of infection, armed with a sense of professional duty and overcoming all odds to end the country’s infectious disease pandemic. This study aims to provide a meta-synthesis of qualitative studies examining the perceptions and experiences of nurses who cared for patients in dedicated COVID-19 hospitals in South Korea. Electronic databases, including RISS, KISS, KMbase, NDSL, KoreaMed, DBpia, PubMed, CINAHL, and Cochrane, were searched for research published until 2023. The study included research using qualitative approaches. These were reviewed and analyzed using a thematic synthesis approach. The quality of the studies was ascertained using the Critical Appraisal Skills Program checklist for qualitative research. Ultimately, 13 studies involving 219 nurses were included in the final review. Six major themes and thirteen subthemes emerged. The six topics are: “The crisis of a pandemic that suddenly appeared”, “Challenges in nursing patients with infectious diseases”, “A struggle in an unknown time due to a prolonged infectious disease”, “Ethical dilemmas in the face of infectious diseases”, “Duality of the social support system”, and “Professional growth for nurses regarding infectious diseases”. During the unexpected COVID-19 pandemic, nurses were able to overcome difficult situations through their interactions with patients, sense of professional mission, and commitment to nursing. Most importantly, they persevered through their collaboration and closeness with fellow nurses, despite confusion about their professional identity, the ethical dilemmas they faced in patient care, and dual attitudes regarding their social support system. To prepare for future infectious disease outbreaks, a multifaceted support system should be established to enable nurses to have positive interactions with their families, colleagues, and patients, which are central to their resilience. Full article
(This article belongs to the Collection COVID-19: Impact on Public Health and Healthcare)
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15 pages, 3054 KiB  
Article
Assessing the Predictive Accuracy of EORTC, CUETO and EAU Risk Stratification Models for High-Grade Recurrence and Progression after Bacillus Calmette–Guérin Therapy in Non-Muscle-Invasive Bladder Cancer
by Aleksander Ślusarczyk, Karolina Garbas, Patryk Pustuła, Łukasz Zapała and Piotr Radziszewski
Cancers 2024, 16(9), 1684; https://doi.org/10.3390/cancers16091684 (registering DOI) - 26 Apr 2024
Abstract
The currently available EORTC, CUETO and EAU2021 risk stratifications were originally developed to predict recurrence and progression in non-muscle-invasive bladder cancer (NMIBC). However, they have not been validated to differentiate between high-grade (HG) and low-grade (LG) recurrence-free survival (RFS), which are distinct events [...] Read more.
The currently available EORTC, CUETO and EAU2021 risk stratifications were originally developed to predict recurrence and progression in non-muscle-invasive bladder cancer (NMIBC). However, they have not been validated to differentiate between high-grade (HG) and low-grade (LG) recurrence-free survival (RFS), which are distinct events with specific implications. We aimed to evaluate the accuracy of available risk models and identify additional risk factors for HG RFS and PFS among NMIBC patients treated with Bacillus Calmette–Guérin (BCG). We retrospectively included 171 patients who underwent transurethral resection of the bladder tumor (TURBT), of whom 73 patients (42.7%) experienced recurrence and 29 (17%) developed progression. Initially, there were 21 low-grade and 52 high-grade recurrences. EORTC2006, EORTC2016 and CUETO recurrence scoring systems lacked accuracy in the prediction of HG RFS (C-index 0.63/0.55/0.59, respectively). EAU2021 risk stratification, EORTC2006, EORTC2016, and CUETO progression scoring systems demonstrated low to moderate accuracy (C-index 0.59/0.68/0.65/0.65) in the prediction of PFS. In the multivariable analysis, T1HG at repeat TURBT (HR = 3.17 p < 0.01), tumor multiplicity (HR = 2.07 p < 0.05), previous history of HG NMIBC (HR = 2.37 p = 0.06) and EORTC2006 progression risk score (HR = 1.1 p < 0.01) were independent predictors for HG RFS. To conclude, available risk models lack accuracy in predicting HG RFS and PFS in -NMIBC patients treated with BCG. Full article
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15 pages, 768 KiB  
Review
Digital Pathology for Better Clinical Practice
by Assia Hijazi, Carlo Bifulco, Pamela Baldin and Jérôme Galon
Cancers 2024, 16(9), 1686; https://doi.org/10.3390/cancers16091686 (registering DOI) - 26 Apr 2024
Abstract
(1) Background: Digital pathology (DP) is transforming the landscape of clinical practice, offering a revolutionary approach to traditional pathology analysis and diagnosis. (2) Methods: This innovative technology involves the digitization of traditional glass slides which enables pathologists to access, analyze, and share high-resolution [...] Read more.
(1) Background: Digital pathology (DP) is transforming the landscape of clinical practice, offering a revolutionary approach to traditional pathology analysis and diagnosis. (2) Methods: This innovative technology involves the digitization of traditional glass slides which enables pathologists to access, analyze, and share high-resolution whole-slide images (WSI) of tissue specimens in a digital format. By integrating cutting-edge imaging technology with advanced software, DP promises to enhance clinical practice in numerous ways. DP not only improves quality assurance and standardization but also allows remote collaboration among experts for a more accurate diagnosis. Artificial intelligence (AI) in pathology significantly improves cancer diagnosis, classification, and prognosis by automating various tasks. It also enhances the spatial analysis of tumor microenvironment (TME) and enables the discovery of new biomarkers, advancing their translation for therapeutic applications. (3) Results: The AI-driven immune assays, Immunoscore (IS) and Immunoscore-Immune Checkpoint (IS-IC), have emerged as powerful tools for improving cancer diagnosis, prognosis, and treatment selection by assessing the tumor immune contexture in cancer patients. Digital IS quantitative assessment performed on hematoxylin–eosin (H&E) and CD3+/CD8+ stained slides from colon cancer patients has proven to be more reproducible, concordant, and reliable than expert pathologists’ evaluation of immune response. Outperforming traditional staging systems, IS demonstrated robust potential to enhance treatment efficiency in clinical practice, ultimately advancing cancer patient care. Certainly, addressing the challenges DP has encountered is essential to ensure its successful integration into clinical guidelines and its implementation into clinical use. (4) Conclusion: The ongoing progress in DP holds the potential to revolutionize pathology practices, emphasizing the need to incorporate powerful AI technologies, including IS, into clinical settings to enhance personalized cancer therapy. Full article
(This article belongs to the Special Issue Predictive Biomarkers for Colorectal Cancer)
20 pages, 8571 KiB  
Technical Note
Airborne Platform Three-Dimensional Positioning Method Based on Interferometric Synthetic Aperture Radar Interferogram Matching
by Lanyu Li, Yachao Wang, Bingnan Wang and Maosheng Xiang
Remote Sens. 2024, 16(9), 1536; https://doi.org/10.3390/rs16091536 (registering DOI) - 26 Apr 2024
Abstract
As the demand for precise navigation of aircraft increases in modern society, researching high-precision, high-autonomy navigation systems is both theoretically valuable and practically significant. Because the inertial navigation system (INS) has systematic and random errors, its output information diverges. Therefore, it is necessary [...] Read more.
As the demand for precise navigation of aircraft increases in modern society, researching high-precision, high-autonomy navigation systems is both theoretically valuable and practically significant. Because the inertial navigation system (INS) has systematic and random errors, its output information diverges. Therefore, it is necessary to combine them with other navigation systems for real-time compensation and correction of these errors. The SAR matching positioning and navigation system uses synthetic aperture radar (SAR) image matching for platform positioning and compensates for the drift caused by errors in the inertial measurement unit (IMU). Images obtained by SAR are matched with digital landmark data, and the platform’s position is calculated based on the SAR imaging geometry. However, SAR matching positioning faces challenges due to seasonal variations in SAR images, the need for typical landmarks for matching, and the lack of elevation information in two-dimensional SAR image matching. This paper proposes an airborne platform positioning method based on interferometric SAR (InSAR) interferogram matching. InSAR interferograms contain terrain elevation information, are less affected by seasonal changes, and provide higher positioning accuracy and robustness. By matching real-time InSAR-processed interferograms with simulated interferograms using a digital elevation model (DEM), three-dimensional position information about the matching points has been obtained. Subsequently, a three-dimensional positioning model for the platform has bene established using the unit line-of-sight vector decomposition method. In actual flight experiments using an FMCW Ku-band Interferometric SAR system, the proposed platform positioning framework demonstrated its ability to achieve precise positioning in the absence of signals from the global navigation satellite system (GNSS). Full article
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32 pages, 3528 KiB  
Article
Identifying Characteristic Fire Properties with Stationary and Non-Stationary Fire Alarm Systems
by Michał Wiśnios, Sebastian Tatko, Michał Mazur, Jacek Paś, Jarosław Mateusz Łukasiak and Tomasz Klimczak
Sensors 2024, 24(9), 2772; https://doi.org/10.3390/s24092772 (registering DOI) - 26 Apr 2024
Abstract
The article reviews issues associated with the operation of stationary and non-stationary electronic fire alarm systems (FASs). These systems are employed for the fire protection of selected buildings (stationary) or to monitor vast areas, e.g., forests, airports, logistics hubs, etc. (non-stationary). An FAS [...] Read more.
The article reviews issues associated with the operation of stationary and non-stationary electronic fire alarm systems (FASs). These systems are employed for the fire protection of selected buildings (stationary) or to monitor vast areas, e.g., forests, airports, logistics hubs, etc. (non-stationary). An FAS is operated under various environmental conditions, indoor and outdoor, favourable or unfavourable to the operation process. Therefore, an FAS has to exhibit a reliable structure in terms of power supply and operation. To this end, the paper discusses a representative FAS monitoring a facility and presents basic tactical and technical assumptions for a non-stationary system. The authors reviewed fire detection methods in terms of fire characteristic values (FCVs) impacting detector sensors. Another part of the article focuses on false alarm causes. Assumptions behind the use of unmanned aerial vehicles (UAVs) with visible-range cameras (e.g., Aviotec) and thermal imaging were presented for non-stationary FASs. The FAS operation process model was defined and a computer simulation related to its operation was conducted. Analysing the FAS operation process in the form of models and graphs, and the conducted computer simulation enabled conclusions to be drawn. They may be applied for the design, ongoing maintenance and operation of an FAS. As part of the paper, the authors conducted a reliability analysis of a selected FAS based on the original performance tests of an actual system in operation. They formulated basic technical and tactical requirements applicable to stationary and mobile FASs detecting the so-called vast fires. Full article
(This article belongs to the Section Environmental Sensing)
15 pages, 2030 KiB  
Article
Berberine Improves Cancer-Derived Myocardial Impairment in Experimental Cachexia Models by Targeting High-Mobility Group Box-1
by Kei Goto, Rina Fujiwara-Tani, Shota Nukaga, Yoshihiro Miyagawa, Isao Kawahara, Ryoichi Nishida, Ayaka Ikemoto, Rika Sasaki, Ruiko Ogata, Shingo Kishi, Yi Luo, Kiyomu Fujii, Hitoshi Ohmori and Hiroki Kuniyasu
Int. J. Mol. Sci. 2024, 25(9), 4735; https://doi.org/10.3390/ijms25094735 (registering DOI) - 26 Apr 2024
Abstract
Cardiac disorders in cancer patients pose significant challenges to disease prognosis. While it has been established that these disorders are linked to cancer cells, the precise underlying mechanisms remain elusive. In this study, we investigated the impact of cancerous ascites from the rat [...] Read more.
Cardiac disorders in cancer patients pose significant challenges to disease prognosis. While it has been established that these disorders are linked to cancer cells, the precise underlying mechanisms remain elusive. In this study, we investigated the impact of cancerous ascites from the rat colonic carcinoma cell line RCN9 on H9c2 cardiomyoblast cells. We found that the ascites reduced mitochondrial volume, increased oxidative stress, and decreased membrane potential in the cardiomyoblast cells, leading to apoptosis and autophagy. Although the ascites fluid contained a substantial amount of high-mobility group box-1 (HMGB1), we observed that neutralizing HMGB1 with a specific antibody mitigated the damage inflicted on myocardial cells. Our mechanistic investigations revealed that HMGB1 activated both nuclear factor κB and phosphoinositide 3-kinases-AKT signals through HMGB1 receptors, namely the receptor for advanced glycation end products and toll-like receptor-4, thereby promoting apoptosis and autophagy. In contrast, treatment with berberine (BBR) induced the expression of miR-181c-5p and miR-340-5p while suppressing HMGB1 expression in RCN9 cells. Furthermore, BBR reduced HMGB1 receptor expression in cardiomyocytes, consequently mitigating HMGB1-induced damage. We validated the myocardial protective effects of BBR in a cachectic rat model. These findings underscore the strong association between HMGB1 and cancer cachexia, highlighting BBR as a promising therapeutic agent for myocardial protection through HMGB1 suppression and modulation of the signaling system. Full article
16 pages, 555 KiB  
Article
Feasibility and Acute Toxicity of Hypo-Fractionated Radiotherapy on 0.35T MR-LINAC: The First Prospective Study in Spain
by Daniela Gonsalves, Abrahams Ocanto, Eduardo Meilan, Alberto Gomez, Jesus Dominguez, Lisselott Torres, Castalia Fernández Pascual, Macarena Teja, Miguel Montijano Linde, Marcos Guijarro, Daniel Rivas, Jose Begara, Jose Antonio González, Jon Andreescu, Esther Holgado, Diego Alcaraz, Escarlata López, Maia Dzhugashvli, Fernando Lopez-Campos, Filippo Alongi and Felipe Couñagoadd Show full author list remove Hide full author list
Cancers 2024, 16(9), 1685; https://doi.org/10.3390/cancers16091685 (registering DOI) - 26 Apr 2024
Abstract
This observational, descriptive, longitudinal, and prospective basket-type study (Registry #5289) prospectively evaluated the feasibility and acute toxicity of hypo-fractionated radiotherapy on the first 0.35T MR-LINAC in Spain. A total of 37 patients were included between August and December 2023, primarily with prostate tumors [...] Read more.
This observational, descriptive, longitudinal, and prospective basket-type study (Registry #5289) prospectively evaluated the feasibility and acute toxicity of hypo-fractionated radiotherapy on the first 0.35T MR-LINAC in Spain. A total of 37 patients were included between August and December 2023, primarily with prostate tumors (59.46%), followed by pancreatic tumors (32.44%). Treatment regimens typically involved extreme hypo-fractionated radiotherapy, with precise dose delivery verified through quality assurance measures. Acute toxicity assessment at treatment completion revealed manageable cystitis, with one case persisting at the three-month follow-up. Gastrointestinal toxicity was minimal. For pancreatic tumors, daily adaptation of organ-at-risk (OAR) and gross tumor volume (GTV) was practiced, with median doses to OAR within acceptable limits. Three patients experienced gastrointestinal toxicity, mainly nausea. Overall, the study demonstrates the feasibility and safety of extreme hypo-fractionated radiotherapy on a 0.35T MR-LINAC, especially for challenging anatomical sites like prostate and pancreatic tumors. These findings support the feasibility of MR-LINAC-based radiotherapy in delivering precise treatments with minimal toxicity, highlighting its potential for optimizing cancer treatment strategies. Full article
(This article belongs to the Special Issue MRI-Guided Real-Time Adaptive Radiotherapy)
22 pages, 2464 KiB  
Article
The Impact of Internet Addiction on Mental Health: Exploring the Mediating Effects of Positive Psychological Capital in University Students
by Girum Tareke Zewude, Derib Gosim Bereded, Endris Abera, Goche Tegegne, Solomon Goraw and Tesfaye Segon
Adolescents 2024, 4(2), 200-221; https://doi.org/10.3390/adolescents4020014 (registering DOI) - 26 Apr 2024
Abstract
Introduction: The widespread use of the internet has brought numerous benefits, but it has also raised concerns about its potential negative impact on mental health, particularly among university students. This study aims to investigate the relationship between internet addiction (IA) and mental [...] Read more.
Introduction: The widespread use of the internet has brought numerous benefits, but it has also raised concerns about its potential negative impact on mental health, particularly among university students. This study aims to investigate the relationship between internet addiction (IA) and mental health (MH) in university students, as well as explore the mediating effects of positive psychological capital (PsyCap) in this relationship. Objective: The main goal of this study was to examine the psychometric properties of the measures and to determine whether internet addiction could negatively predict university students’ mental health, mediated through PsyCap. Method: A cross-sectional design with an inferential approach was employed to address this objective. The data were collected using the Psychological Capital Questionnaire (PCQ-24), Internet Addiction Scale (IAS), and Keyes’ Mental Health Continuum-Short Form (MHC-SF). The total sample of this study comprised 850 students from two large public higher education institutions in Ethiopia, of whom 334 (39.3%) were female and 516 (60.7%) were male, with a mean age of 22.32 (SD = 4.04). Several analyses were performed to achieve the stated objectives, such as Cronbach’s alpha and composite reliabilities, bivariate correlation, discriminant validity, common method biases, and structural equation modeling (confirmatory factor analysis, path analysis, and mediation analysis). Confirmatory factor analysis was conducted to test the construct validity of IAS, PCQ-24, and MHC-SF. Additionally, the mediating model was examined using structural equation modeling with the corrected biased bootstrap method. Results: The preliminary study results found that the construct validity of IAS, PCQ-24, and MHC-SF was excellent and appropriate. Furthermore, the findings demonstrate that internet addiction had a negative and direct effect on PsyCap and MH. Moreover, PsyCap fully mediated the relationship between IA and MH. Additionally, this study confirmed that all the scales exhibited strong internal consistency and good psychometric properties. Conclusion: This study contributes to a better understanding of the complex interplay between IA, PsyCap, and MH among university students, confirming previous findings. Recommendation: The findings, discussed in relation to the recent and relevant literature, will be valuable for practitioners and researchers aiming to improve mental health and reduce internet addiction by utilizing positive psychological resources as protective factors for university students. Full article
(This article belongs to the Section Adolescent Health and Mental Health)
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15 pages, 1499 KiB  
Article
Gallic Acid Can Promote Low-Density Lipoprotein Uptake in HepG2 Cells via Increasing Low-Density Lipoprotein Receptor Accumulation
by Dongying Zhang, Qixing Zhou, Xiangxuan Yang, Zhen Zhang, Dongxue Wang, Dandan Hu, Yewei Huang, Jun Sheng and Xuanjun Wang
Molecules 2024, 29(9), 1999; https://doi.org/10.3390/molecules29091999 (registering DOI) - 26 Apr 2024
Abstract
Gallic acid (GA) is a type of polyphenolic compound that can be found in a range of fruits, vegetables, and tea. Although it has been confirmed it improves non-alcoholic fatty liver disease (NAFLD), it is still unknown whether GA can improve the occurrence [...] Read more.
Gallic acid (GA) is a type of polyphenolic compound that can be found in a range of fruits, vegetables, and tea. Although it has been confirmed it improves non-alcoholic fatty liver disease (NAFLD), it is still unknown whether GA can improve the occurrence of NAFLD by increasing the low-density lipoprotein receptor (LDLR) accumulation and alleviating cholesterol metabolism disorders. Therefore, the present study explored the effect of GA on LDLR and its mechanism of action. The findings indicated that the increase in LDLR accumulation in HepG2 cells induced by GA was associated with the stimulation of the epidermal growth factor receptor–extracellular regulated protein kinase (EGFR-ERK1/2) signaling pathway. When the pathway was inhibited by EGFR mab cetuximab, it was observed that the activation of the EGFR-ERK1/2 signaling pathway induced by GA was also blocked. At the same time, the accumulation of LDLR protein and the uptake of LDL were also suppressed. Additionally, GA can also promote the accumulation of forkhead box O3 (FOXO3) and suppress the accumulation of hepatocyte nuclear factor-1α (HNF1α), leading to the inhibition of proprotein convertase subtilisin/kexin 9 (PCSK9) mRNA expression and protein accumulation. This ultimately results in increased LDLR protein accumulation and enhanced uptake of LDL in cells. In summary, the present study revealed the potential mechanism of GA’s role in ameliorating NAFLD, with a view of providing a theoretical basis for the dietary supplementation of GA. Full article
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17 pages, 5807 KiB  
Article
Cinnamaldehyde Protects against P. gingivalis Induced Intestinal Epithelial Barrier Dysfunction in IEC-6 Cells via the PI3K/Akt-Mediated NO/Nrf2 Signaling Pathway
by Chethan Sampath, Sasanka S. Chukkapalli, Abhinav V. Raju, Leela Subhashini C. Alluri, Dollada Srisai and Pandu R. Gangula
Int. J. Mol. Sci. 2024, 25(9), 4734; https://doi.org/10.3390/ijms25094734 (registering DOI) - 26 Apr 2024
Abstract
Porphyromonas gingivalis (Pg), a Gram-negative oral pathogen, promotes and accelerates periodontitis-associated gut disorders. Intestinal epithelial barrier dysfunction is crucial in the pathogenesis of intestinal and systemic diseases. In this study, we sought to elucidate the protective role of cinnamaldehyde (CNM, an [...] Read more.
Porphyromonas gingivalis (Pg), a Gram-negative oral pathogen, promotes and accelerates periodontitis-associated gut disorders. Intestinal epithelial barrier dysfunction is crucial in the pathogenesis of intestinal and systemic diseases. In this study, we sought to elucidate the protective role of cinnamaldehyde (CNM, an activator of Nrf2) against P. gingivalis (W83) and Pg-derived lipopolysaccharide (Pg-LPS) induced intestinal epithelial barrier dysfunction via antioxidative mechanisms in IEC-6 cells. IEC-6 (ATCC, CRL-1592) cells were pretreated with or without CNM (100 µM), in the presence or absence of P. gingivalis (strain W83, 109 MOI) or Pg-LPS (1, 10, and 100 µg/mL), respectively, between 0–72 h time points by adopting a co-culture method. Intestinal barrier function, cytokine secretion, and intestinal oxidative stress protein markers were analyzed. P. gingivalis or Pg-LPS significantly (p < 0.05) increased reactive oxygen species (ROS) and malondialdehyde (MDA) levels expressing oxidative stress damage. Pg-LPS, as well as Pg alone, induces inflammatory cytokines via TLR-4 signaling. Furthermore, infection reduced Nrf2 and NAD(P)H quinone dehydrogenase 1 (NQO1). Interestingly, inducible nitric oxide synthase (iNOS) protein expression significantly (p < 0.05) increased with Pg-LPS or Pg infection, with elevated levels of nitric oxide (NO). CNM treatment suppressed both Pg- and Pg-LPS-induced intestinal oxidative stress damage by reducing ROS, MDA, and NO production. Furthermore, CNM treatment significantly upregulated the expression of tight junction proteins via increasing the phosphorylation levels of PI3K/Akt/Nrf2 suppressing inflammatory cytokines. CNM protected against Pg infection-induced intestinal epithelial barrier dysfunction by activating the PI3K/Akt-mediated Nrf2 signaling pathway in IEC-6 cells. Full article
(This article belongs to the Special Issue Nitric Oxide Synthases: Function and Regulation 2.0)
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