The 2023 MDPI Annual Report has
been released!
 
28 pages, 1010 KiB  
Article
On the Structure of SO(3): Trace and Canonical Decompositions
by Demeter Krupka and Ján Brajerčík
Mathematics 2024, 12(10), 1490; https://doi.org/10.3390/math12101490 (registering DOI) - 10 May 2024
Abstract
This paper is devoted to some selected topics of the theory of special orthogonal group SO(3). First, we discuss the trace of orthogonal matrices and its relation to the characteristic polynomial; on this basis, the partition of SO(3) formed by conjugation classes is [...] Read more.
This paper is devoted to some selected topics of the theory of special orthogonal group SO(3). First, we discuss the trace of orthogonal matrices and its relation to the characteristic polynomial; on this basis, the partition of SO(3) formed by conjugation classes is described by trace mapping. Second, we show that every special orthogonal matrix can be expressed as the product of three elementary special orthogonal matrices. Explicit formulas for the decomposition as needed for applications in differential geometry and physics as symmetry transformations are given. Full article
(This article belongs to the Special Issue Differentiable Manifolds and Geometric Structures)
23 pages, 352 KiB  
Article
Convergence Results for History-Dependent Variational Inequalities
by Mircea Sofonea and Domingo A. Tarzia
Axioms 2024, 13(5), 316; https://doi.org/10.3390/axioms13050316 (registering DOI) - 10 May 2024
Abstract
We consider a history-dependent variational inequality in a real Hilbert space, for which we recall an existence and uniqueness result. We associate this inequality with a gap function, together with two additional problems: a nonlinear equation and a minimization problem. Then, we prove [...] Read more.
We consider a history-dependent variational inequality in a real Hilbert space, for which we recall an existence and uniqueness result. We associate this inequality with a gap function, together with two additional problems: a nonlinear equation and a minimization problem. Then, we prove that solving these problems is equivalent to solving the original history-dependent variational inequality. Next, we state and prove a convergence criterion, i.e., we provide necessary and sufficient conditions which guarantee the convergence of a sequence of functions to the solution of the considered inequality. Based on the equivalence above, we deduce various consequences that present some interest on their own, and, moreover, we obtain convergence results for the two additional problems considered. Finally, we apply our abstract results to the study of an inequality problem in solid mechanics. It concerns the study of a viscoelastic constitutive law with long memory and unilateral constraints, for which we deduce a convergence result and provide the corresponding mechanical interpretations. Full article
(This article belongs to the Section Hilbert’s Sixth Problem)
9 pages, 993 KiB  
Article
A New Species and a New Record of Byssoid Arthoniaceae (Lichenized Ascomycota) from Southern China
by Lulu Zhang, Junxia Xue and Linlin Liu
Diversity 2024, 16(5), 287; https://doi.org/10.3390/d16050287 (registering DOI) - 10 May 2024
Abstract
This paper illustrates two species in the lichen-forming family Arthoniaceae from southern China, including a new species of Herpothallon, H. fibrosum L.L. Liu & Lu L. Zhang and a new record of Cryptothecia, C. striata G. Thor for China. Herpothallon [...] Read more.
This paper illustrates two species in the lichen-forming family Arthoniaceae from southern China, including a new species of Herpothallon, H. fibrosum L.L. Liu & Lu L. Zhang and a new record of Cryptothecia, C. striata G. Thor for China. Herpothallon fibrosum has fluffy, cylindrical pseudoisidia, like a bundle of fiber, and psoromic acid and confluentic acid are present. Furthermore, the new record of Cryptothecia striata has been identified by morphological, anatomical, chemical, and molecular studies. The systematic position of the two species was clarified by the molecular sequence data from the small subunit of the mitochondrial ribosomal DNA (mtSSU). Detailed taxonomic descriptions, chemical characters, comparisons, and discussion of the characteristics of similar species are provided for the two species; the relationship between Cryptothecia and Herpothallon is also discussed here. Full article
(This article belongs to the Special Issue Phylogeny, Taxonomy and Ecosystems of Lichens)
12 pages, 885 KiB  
Article
Disclosing the Antifungal Mechanisms of the Cyclam Salt H4[H2(4-CF3PhCH2)2Cyclam]Cl4 against Candida albicans and Candida krusei
by Inês Costa, Inês Lopes, Mariana Morais, Renata Silva, Fernando Remião, Rui Medeiros, Luís G. Alves, Eugénia Pinto and Fátima Cerqueira
Int. J. Mol. Sci. 2024, 25(10), 5209; https://doi.org/10.3390/ijms25105209 (registering DOI) - 10 May 2024
Abstract
Mycoses are one of the major causes of morbidity/mortality among immunocompromised individuals. Considering the importance of these infections, the World Health Organization (WHO) defined a priority list of fungi for health in 2022 that include Candida albicans as belonging to the critical priority [...] Read more.
Mycoses are one of the major causes of morbidity/mortality among immunocompromised individuals. Considering the importance of these infections, the World Health Organization (WHO) defined a priority list of fungi for health in 2022 that include Candida albicans as belonging to the critical priority group and Pichia kudriavzevii (Candida krusei) to the medium priority group. The existence of few available antifungal drugs, their high toxicity, the acquired fungal resistance, and the appearance of new species with a broader spectrum of resistance, points out the need for searching for new antifungals, preferably with new and multiple mechanisms of action. The cyclam salt H4[H2(4-CF3PhCH2)2Cyclam]Cl4 was previously tested against several fungi and revealed an interesting activity, with minimal inhibitory concentration (MIC) values of 8 µg/mL for C. krusei and of 128 µg/mL for C. albicans. The main objective of the present work was to deeply understand the mechanisms involved in its antifungal activity. The effects of the cyclam salt on yeast metabolic viability (resazurin reduction assay), yeast mitochondrial function (JC-1 probe), production of reactive oxygen species (DCFH-DA probe) and on intracellular ATP levels (luciferin/luciferase assay) were evaluated. H4[H2(4-CF3PhCH2)2Cyclam]Cl4 induced a significant decrease in the metabolic activity of both C. albicans and C. krusei, an increase in Reactive Oxygen Species (ROS) production, and an impaired mitochondrial function. The latter was observed by the depolarization of the mitochondrial membrane and decrease in ATP intracellular levels, mechanisms that seems to be involved in the antifungal activity of H4[H2(4-CF3PhCH2)2Cyclam]Cl4. The interference of the cyclam salt with human cells revealed a CC50 value against HEK-293 embryonic kidney cells of 1.1 mg/mL and a HC10 value against human red blood cells of 0.8 mg/mL. Full article
(This article belongs to the Special Issue Antifungal Drug Design, Synthesis and Molecular Mechanisms)
31 pages, 1772 KiB  
Review
Estimating Economic and Livelihood Values of the World’s Largest Mangrove Forest (Sundarbans): A Meta-Analysis
by Akbar Hossain Kanan, Mauro Masiero and Francesco Pirotti
Forests 2024, 15(5), 837; https://doi.org/10.3390/f15050837 (registering DOI) - 10 May 2024
Abstract
We explored the state of the art economic and livelihood valuation of ecosystem services (ES) in the Sundarbans mangroves, including a comparative analysis between the Bangladesh and Indian parts of the region. We identified 145 values from 26 studies to estimate the Sundarbans’ [...] Read more.
We explored the state of the art economic and livelihood valuation of ecosystem services (ES) in the Sundarbans mangroves, including a comparative analysis between the Bangladesh and Indian parts of the region. We identified 145 values from 26 studies to estimate the Sundarbans’ economic and livelihood values. The number of ES valuation studies of the Sundarbans is scant, and it has gradually increased over time, focusing mainly on the estimation of provisioning ES (66.2%), followed by regulating and maintenance (25.5%), and cultural (8.3%) ES. However, recently, attention has been paid to estimation, regulating and maintenance, and cultural ES. The number of studies on ES was higher for the Bangladesh (73%) part of the Sundarbans than the Indian (27%) one. The estimated economic values of the Sundarbans’ provisioning, regulating and maintenance, and cultural ES were US $ 713.30 ha−1 yr−1, US $ 2584.46 ha−1 yr−1, and US $ 151.88 ha−1 yr−1, respectively. Except for cultural ES, the identified values for the other two ES categories were about 1.5 to 2.5 times higher for the Bangladesh Sundarbans compared to the Indian ones. The results of the meta-regression model showed that the estimated economic and livelihood values of ES are affected by the associated variables (e.g., type of ES, valuation methods, study area, population, and GDP). Our study also identified some remarkable gaps and limitations in the economic and livelihood valuation of the ES of the Sundarbans, highlighting the need for further research to find out the values of all ES to help with policy decision-making. Full article
(This article belongs to the Special Issue Economic Valuation of Forest Resources)
25 pages, 2999 KiB  
Article
Sparse-View Spectral CT Reconstruction Based on Tensor Decomposition and Total Generalized Variation
by Xuru Li, Kun Wang, Xiaoqin Xue and Fuzhong Li
Electronics 2024, 13(10), 1868; https://doi.org/10.3390/electronics13101868 (registering DOI) - 10 May 2024
Abstract
Spectral computed tomography (CT)-reconstructed images often exhibit severe noise and artifacts, which compromise the practical application of spectral CT imaging technology. Methods that use tensor dictionary learning (TDL) have shown superior performance, but it is difficult to obtain a high-quality pre-trained global tensor [...] Read more.
Spectral computed tomography (CT)-reconstructed images often exhibit severe noise and artifacts, which compromise the practical application of spectral CT imaging technology. Methods that use tensor dictionary learning (TDL) have shown superior performance, but it is difficult to obtain a high-quality pre-trained global tensor dictionary in practice. In order to resolve this problem, this paper develops an algorithm called tensor decomposition with total generalized variation (TGV) for sparse-view spectral CT reconstruction. In the process of constructing tensor volumes, the proposed algorithm utilizes the non-local similarity feature of images to construct fourth-order tensor volumes and uses Canonical Polyadic (CP) tensor decomposition instead of pre-trained tensor dictionaries to further explore the inter-channel correlation of images. Simultaneously, introducing the TGV regularization term to characterize spatial sparsity features, the use of higher-order derivatives can better adapt to different image structures and noise levels. The proposed objective minimization model has been addressed using the split-Bregman algorithm. To assess the performance of the proposed algorithm, several numerical simulations and actual preclinical mice are studied. The final results demonstrate that the proposed algorithm has an enormous improvement in the quality of spectral CT images when compared to several existing competing algorithms. Full article
(This article belongs to the Special Issue Pattern Recognition and Machine Learning Applications, 2nd Edition)
20 pages, 1827 KiB  
Article
Robust CA-GO-TiO2/PTFE Photocatalytic Membranes for the Degradation of the Azithromycin Formulation from Wastewaters
by Veronica Satulu, Andreea Madalina Pandele, Giovanina-Iuliana Ionica, Liliana Bobirică, Anca Florina Bonciu, Alexandra Scarlatescu, Constantin Bobirică, Cristina Orbeci, Stefan Ioan Voicu, Bogdana Mitu and Gheorghe Dinescu
Polymers 2024, 16(10), 1368; https://doi.org/10.3390/polym16101368 (registering DOI) - 10 May 2024
Abstract
We have developed an innovative thin-film nanocomposite membrane that contains cellulose acetate (CA) with small amounts of TiO2-decorated graphene oxide (GO) (ranging from 0.5 wt.% to 2 wt.%) sandwiched between two polytetrafluoroethylene (PTFE)-like thin films. The PTFE-like films succeeded in maintaining [...] Read more.
We have developed an innovative thin-film nanocomposite membrane that contains cellulose acetate (CA) with small amounts of TiO2-decorated graphene oxide (GO) (ranging from 0.5 wt.% to 2 wt.%) sandwiched between two polytetrafluoroethylene (PTFE)-like thin films. The PTFE-like films succeeded in maintaining the bulk porosity of the support while increasing the thermal and chemical robustness of the membrane and boosting the catalytic activity of TiO2 nanoparticles. The membranes exhibited a specific chemical composition and bonding, with predominant carbon–oxygen bonds from CA and GO in the bulk, and carbon–fluorine bonds on their PTFE-like coated sides. We have also tested the membranes’ photocatalytic activities on azithromycin-containing wastewaters, demonstrating excellent efficiency with more than 80% degradation for 2 wt.% TiO2-decorated GO in the CA-GO-TiO2/PTFE-like membranes. The degradation of the azithromycin formulation occurs in two steps, with reaction rates being correlated to the amount of GO-TiO2 in the membranes. Full article
(This article belongs to the Special Issue Advances in Cellulose-Based Polymers and Composites)
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18 pages, 7498 KiB  
Article
Core Optimization for Extending the Graphite Irradiation Lifespan in a Small Modular Thorium-Based Molten Salt Reactor
by Xuzhong Kang, Guifeng Zhu, Jianhui Wu, Rui Yan, Yang Zou and Yafen Liu
J. Nucl. Eng. 2024, 5(2), 168-185; https://doi.org/10.3390/jne5020012 (registering DOI) - 10 May 2024
Abstract
The lifespan of core graphite under neutron irradiation in a commercial molten salt reactor (MSR) has an important influence on its economy. Flattening the fast neutron flux (≥0.05 MeV) distribution in the core is the main method to extend the graphite irradiation lifespan. [...] Read more.
The lifespan of core graphite under neutron irradiation in a commercial molten salt reactor (MSR) has an important influence on its economy. Flattening the fast neutron flux (≥0.05 MeV) distribution in the core is the main method to extend the graphite irradiation lifespan. In this paper, the effects of the key parameters of MSRs on fast neutron flux distribution, including volume fraction (VF) of fuel salt, pitch of hexagonal fuel assembly, core zoning, and layout of control rod assemblies, were studied. The fast neutron flux distribution in a regular hexagon fuel assembly was first analyzed by varying VF and pitch. It was demonstrated that changing VF is more effective in reducing the fast neutron flux in both global and local graphite blocks. Flattening the fast neutron flux distribution of a commercial MSR core was then carried out by zoning the core into two regions under different VFs. Considering both the fast neutron flux distribution and burnup depth, an optimized core was obtained. The fast neutron flux distribution of the optimized core was further flattened by the rational arrangement of control rod channels. The calculation results show that the final optimized core could reduce the maximum fast neutron flux of the graphite blocks by about 30% and result in a more negative temperature reactivity coefficient, while slightly decreasing the burnup and maintaining a fully acceptable core temperature distribution. Full article
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19 pages, 7014 KiB  
Article
Integrated Metabolomics and Transcriptomics Analysis of Flavonoid Biosynthesis Pathway in Polygonatum cyrtonema Hua
by Luyun Yang, Qingwen Yang, Luping Zhang, Fengxiao Ren, Zhouyao Zhang and Qiaojun Jia
Molecules 2024, 29(10), 2248; https://doi.org/10.3390/molecules29102248 (registering DOI) - 10 May 2024
Abstract
Flavonoids, a class of phenolic compounds, are one of the main functional components and have a wide range of molecular structures and biological activities in Polygonatum. A few of them, including homoisoflavonoids, chalcones, isoflavones, and flavones, were identified in Polygonatum and displayed [...] Read more.
Flavonoids, a class of phenolic compounds, are one of the main functional components and have a wide range of molecular structures and biological activities in Polygonatum. A few of them, including homoisoflavonoids, chalcones, isoflavones, and flavones, were identified in Polygonatum and displayed a wide range of powerful biological activities, such as anti-cancer, anti-viral, and blood sugar regulation. However, few studies have systematically been published on the flavonoid biosynthesis pathway in Polygonatum cyrtonema Hua. Therefore, in the present study, a combined transcriptome and metabolome analysis was performed on the leaf, stem, rhizome, and root tissues of P. cyrtonema to uncover the synthesis pathway of flavonoids and to identify key regulatory genes. Flavonoid-targeted metabolomics detected a total of 65 active substances from four different tissues, among which 49 substances were first study to identify in Polygonatum, and 38 substances were flavonoids. A total of 19 differentially accumulated metabolites (DAMs) (five flavonols, three flavones, two dihydrochalcones, two flavanones, one flavanol, five phenylpropanoids, and one coumarin) were finally screened by KEGG enrichment analysis. Transcriptome analysis indicated that a total of 222 unigenes encoding 28 enzymes were annotated into three flavonoid biosynthesis pathways, which were “phenylpropanoid biosynthesis”, “flavonoid biosynthesis”, and “flavone and flavonol biosynthesis”. The combined analysis of the metabolome and transcriptome revealed that 37 differentially expressed genes (DEGs) encoding 11 enzymes (C4H, PAL, 4CL, CHS, CHI, F3H, DFR, LAR, ANR, FNS, FLS) and 19 DAMs were more likely to be regulated in the flavonoid biosynthesis pathway. The expression of 11 DEGs was validated by qRT-PCR, resulting in good agreement with the RNA-Seq. Our studies provide a theoretical basis for further elucidating the flavonoid biosynthesis pathway in Polygonatum. Full article
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18 pages, 16065 KiB  
Article
A Novel Frame-Selection Metric for Video Inpainting to Enhance Urban Feature Extraction
by Yuhu Feng, Jiahuan Zhang, Guang Li, Ren Togo, Keisuke Maeda, Takahiro Ogawa and Miki Haseyama
Sensors 2024, 24(10), 3035; https://doi.org/10.3390/s24103035 (registering DOI) - 10 May 2024
Abstract
In our digitally driven society, advances in software and hardware to capture video data allow extensive gathering and analysis of large datasets. This has stimulated interest in extracting information from video data, such as buildings and urban streets, to enhance understanding of the [...] Read more.
In our digitally driven society, advances in software and hardware to capture video data allow extensive gathering and analysis of large datasets. This has stimulated interest in extracting information from video data, such as buildings and urban streets, to enhance understanding of the environment. Urban buildings and streets, as essential parts of cities, carry valuable information relevant to daily life. Extracting features from these elements and integrating them with technologies such as VR and AR can contribute to more intelligent and personalized urban public services. Despite its potential benefits, collecting videos of urban environments introduces challenges because of the presence of dynamic objects. The varying shape of the target building in each frame necessitates careful selection to ensure the extraction of quality features. To address this problem, we propose a novel evaluation metric that considers the video-inpainting-restoration quality and the relevance of the target object, considering minimizing areas with cars, maximizing areas with the target building, and minimizing overlapping areas. This metric extends existing video-inpainting-evaluation metrics by considering the relevance of the target object and interconnectivity between objects. We conducted experiment to validate the proposed metrics using real-world datasets from Japanese cities Sapporo and Yokohama. The experiment results demonstrate feasibility of selecting video frames conducive to building feature extraction. Full article
(This article belongs to the Topic Applications in Image Analysis and Pattern Recognition)
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30 pages, 1772 KiB  
Review
Tumor versus Tumor Cell Targeting in Metal-Based Nanoparticles for Cancer Theranostics
by Jesús David Urbano-Gámez, Cinzia Guzzi, Manuel Bernal, Juan Solivera, Iñigo Martínez-Zubiaurre, Carlos Caro and María Luisa García-Martín
Int. J. Mol. Sci. 2024, 25(10), 5213; https://doi.org/10.3390/ijms25105213 (registering DOI) - 10 May 2024
Abstract
 The application of metal-based nanoparticles (mNPs) in cancer therapy and diagnostics (theranostics) has been a hot research topic since the early days of nanotechnology, becoming even more relevant in recent years. However, the clinical translation of this technology has been notably poor, [...] Read more.
 The application of metal-based nanoparticles (mNPs) in cancer therapy and diagnostics (theranostics) has been a hot research topic since the early days of nanotechnology, becoming even more relevant in recent years. However, the clinical translation of this technology has been notably poor, with one of the main reasons being a lack of understanding of the disease and conceptual errors in the design of mNPs. Strikingly, throughout the reported studies to date on in vivo experiments, the concepts of “tumor targeting” and “tumor cell targeting” are often intertwined, particularly in the context of active targeting. These misconceptions may lead to design flaws, resulting in failed theranostic strategies. In the context of mNPs, tumor targeting can be described as the process by which mNPs reach the tumor mass (as a tissue), while tumor cell targeting refers to the specific interaction of mNPs with tumor cells once they have reached the tumor tissue. In this review, we conduct a critical analysis of key challenges that must be addressed for the successful targeting of either tumor tissue or cancer cells within the tumor tissue. Additionally, we explore essential features necessary for the smart design of theranostic mNPs, where ‘smart design’ refers to the process involving advanced consideration of the physicochemical features of the mNPs, targeting motifs, and physiological barriers that must be overcome for successful tumor targeting and/or tumor cell targeting. Full article
(This article belongs to the Special Issue Application of Nanostructures in Biology and Medicine)
19 pages, 65974 KiB  
Article
Experimental Study on the Performance of Glass/Basalt Fiber Reinforced Concrete Unidirectional Plate under Impact Load
by Liancheng Li, Jueliang Chen, Siyu Liu, Xin Huang and Hui Chen
Buildings 2024, 14(5), 1367; https://doi.org/10.3390/buildings14051367 (registering DOI) - 10 May 2024
Abstract
Fiber-reinforced composite materials have emerged as essential solutions for addressing the durability challenges of traditional reinforced concrete, owing to their lightweight nature, high strength, ease of construction, superior tensile capacity, robust corrosion resistance, and excellent electromagnetic insulation properties. This paper delves into the [...] Read more.
Fiber-reinforced composite materials have emerged as essential solutions for addressing the durability challenges of traditional reinforced concrete, owing to their lightweight nature, high strength, ease of construction, superior tensile capacity, robust corrosion resistance, and excellent electromagnetic insulation properties. This paper delves into the influence of loading rate and fiber bar type on the mechanical characteristics of concrete one-way plates through impact experiments on such plates fitted with glass/basalt fiber bars at varying drop weight heights. The test results reveal a direct correlation between increasing loading rates and escalating damage in fiber-reinforced concrete one-way plates, reflected in the progressive rise in peak deflection and residual displacement at the mid-span of the specimens. Notably, when subjected to higher impact loads, glass fiber-reinforced concrete specimens exhibit amplified deformation and intricate crack formations, consequently diminishing the overall deformation resistance of the plate. Furthermore, glass/basalt fiber-reinforced composites demonstrate notable vibration damping qualities, characterized by substantial residual displacement, minimal rebound, and rapid decay following vibration stimulation. Overall, glass fiber-reinforced one-way plates display marginally superior impact resistance compared to their basalt fiber-reinforced counterparts. Full article
(This article belongs to the Special Issue Low-Carbon and Green Materials in Construction—2nd Edition)
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11 pages, 283 KiB  
Article
The Prevalence and Risk Factors of Postpartum Depression among Mothers in Najran City, Saudi Arabia
by Majed Alshahrani, Nisreen Oudah Tami Alqarni, Sarah Saeed Aldughar, Shuruq Talea Asiri and Ruba Ibrahim Alharbi
Healthcare 2024, 12(10), 986; https://doi.org/10.3390/healthcare12100986 (registering DOI) - 10 May 2024
Abstract
Background: Postpartum depression (PPD) is a significant mental health concern affecting mothers globally. However, research on PPD prevalence and risk factors in Najran City, Saudi Arabia, is limited. Study Aim: this cross-sectional study aimed to determine the prevalence and risk factors associated with [...] Read more.
Background: Postpartum depression (PPD) is a significant mental health concern affecting mothers globally. However, research on PPD prevalence and risk factors in Najran City, Saudi Arabia, is limited. Study Aim: this cross-sectional study aimed to determine the prevalence and risk factors associated with PPD among mothers in Najran City. Methodology: A questionnaire-based study was conducted from September 2023 to January 2024, involving 420 mothers aged 16–50 years with newborns (2–10 weeks after delivery). The questionnaire included demographic information and the Arabic version of the Edinburgh Postnatal Depression Scale (EPDS). Statistical analysis utilized SPSS software v. 26, including descriptive statistics, Mann–Whitney U test, Kruskal–Wallis H test, and logistic regression. Results: The majority of participants were aged 20–35 years (61.4%), Saudi nationals (87.6%), and had university education (51.4%). EPDS scores indicated that 66.7% of mothers screened positive for possible depression. Significant associations were found between higher EPDS scores and factors such as unemployment (p = 0.004), younger age (p = 0.003), caesarean delivery (p = 0.043), mental illness (p = 0.0001), lack of adequate family support (p = 0.0001), and higher stress levels (p = 0.0001). Conclusion: The study revealed a high prevalence of PPD among mothers in Najran City, with sociodemographic, obstetric, and psychosocial factors significantly influencing PPD risk. These findings emphasize the need for targeted interventions and support systems to address maternal mental health needs effectively. Full article
20 pages, 334 KiB  
Article
Parameter Estimation in Spatial Autoregressive Models with Missing Data and Measurement Errors
by Tengjun Li, Zhikang Zhang and Yunquan Song
Axioms 2024, 13(5), 315; https://doi.org/10.3390/axioms13050315 (registering DOI) - 10 May 2024
Abstract
This study addresses the problem of parameter estimation in spatial autoregressive models with missing data and measurement errors in covariates. Specifically, a corrected likelihood estimation approach is employed to rectify the bias in the log-maximum likelihood function induced by measurement errors. Additionally, a [...] Read more.
This study addresses the problem of parameter estimation in spatial autoregressive models with missing data and measurement errors in covariates. Specifically, a corrected likelihood estimation approach is employed to rectify the bias in the log-maximum likelihood function induced by measurement errors. Additionally, a combination of inverse probability weighting (IPW) and mean imputation is utilized to mitigate the bias caused by missing data. Under several mild conditions, it is demonstrated that the proposed estimators are consistent and possess oracle properties. The efficacy of the proposed parameter estimation process is assessed through Monte Carlo simulation studies. Finally, the applicability of the proposed method is further substantiated using the Boston Housing Dataset. Full article
(This article belongs to the Special Issue Mathematical and Statistical Methods and Their Applications)
13 pages, 7089 KiB  
Article
Leptin Promotes Vasculogenic Mimicry in Breast Cancer Cells by Regulating Aquaporin-1
by Deok-Soo Han and Eun-Ok Lee
Int. J. Mol. Sci. 2024, 25(10), 5215; https://doi.org/10.3390/ijms25105215 (registering DOI) - 10 May 2024
Abstract
Leptin is an obesity-related hormone that plays an important role in breast cancer progression. Vasculogenic mimicry (VM) refers to the formation of vascular channels lined by tumor cells. This study aimed to investigate the relationship between leptin and VM in human breast cancer [...] Read more.
Leptin is an obesity-related hormone that plays an important role in breast cancer progression. Vasculogenic mimicry (VM) refers to the formation of vascular channels lined by tumor cells. This study aimed to investigate the relationship between leptin and VM in human breast cancer cells. VM was measured by a 3D culture assay. Signal transducers and activators of transcription 3 (STAT3) signaling, aquaporin-1 (AQP1), and the expression of VM-related proteins, including vascular endothelial cadherin (VE-cadherin), twist, matrix metalloproteinase-2 (MMP-2), and laminin subunit 5 gamma-2 (LAMC2), were examined by Western blot. AQP1 mRNA was analyzed by a reverse transcriptase-polymerase chain reaction (RT-PCR). Leptin increased VM and upregulated phospho-STAT3, VE-cadherin, twist, MMP-2, and LAMC2. These effects were inhibited by the leptin receptor-blocking peptide, Ob-R BP, and the STAT3 inhibitor, AG490. A positive correlation between leptin and AQP1 mRNA was observed and was confirmed by RT-PCR. Leptin upregulated AQP1 expression, which was blocked by Ob-R BP and AG490. AQP1 overexpression increased VM and the expression of VM-related proteins. AQP1 silencing inhibited leptin-induced VM and the expression of VM-related proteins. Thus, these results showed that leptin facilitates VM in breast cancer cells via the Ob-R/STAT3 pathway and that AQP1 is a key mediator in leptin-induced VM. Full article
(This article belongs to the Special Issue Cancer Biomarkers and Bioinformatics)
19 pages, 321 KiB  
Article
Some New Results on Stochastic Comparisons of Spacings of Generalized Order Statistics from One and Two Samples
by Maryam Esna-Ashari, Mahdi Alimohammadi, Elnaz Garousi and Antonio Di Crescenzo
Mathematics 2024, 12(10), 1489; https://doi.org/10.3390/math12101489 (registering DOI) - 10 May 2024
Abstract
Generalized order statistics (GOSs) are often adopted as a tool for providing a unified approach to several stochastic models dealing with ordered random variables. In this contribution, we first recall various useful results based on the notion of total positivity. Then, some stochastic [...] Read more.
Generalized order statistics (GOSs) are often adopted as a tool for providing a unified approach to several stochastic models dealing with ordered random variables. In this contribution, we first recall various useful results based on the notion of total positivity. Then, some stochastic comparisons between spacings of GOSs from one sample, as well as two samples, are developed under the more general assumptions on the parameters of the model. Specifically, the given results deal with the likelihood ratio order, the hazard rate order and the mean residual life order. Finally, an application is demonstrated for sequential systems. Full article
(This article belongs to the Section Probability and Statistics)
35 pages, 15372 KiB  
Review
Wireless Power Transfer for Unmanned Underwater Vehicles: Technologies, Challenges and Applications
by Iñigo Martínez de Alegría, Iñigo Rozas Holgado, Edorta Ibarra, Eider Robles and José Luís Martín
Energies 2024, 17(10), 2305; https://doi.org/10.3390/en17102305 (registering DOI) - 10 May 2024
Abstract
Unmanned underwater vehicles (UUVs) are key technologies to conduct preventive inspection and maintenance tasks in offshore renewable energy plants. Making such vehicles autonomous would lead to benefits such as improved availability, cost reduction and carbon emission minimization. However, some technological aspects, including the [...] Read more.
Unmanned underwater vehicles (UUVs) are key technologies to conduct preventive inspection and maintenance tasks in offshore renewable energy plants. Making such vehicles autonomous would lead to benefits such as improved availability, cost reduction and carbon emission minimization. However, some technological aspects, including the powering of these devices, remain with a long way to go. In this context, underwater wireless power transfer (UWPT) solutions have potential to overcome UUV powering drawbacks. Considering the relevance of this topic for offshore renewable plants, this work aims to provide a comprehensive summary of the state of the art regarding UPWT technologies. A technology intelligence study is conducted by means of a bibliographical survey. Regarding underwater wireless power transfer, the main methods are reviewed, and it is concluded that inductive wireless power transfer (IWPT) technologies have the most potential. These inductive systems are described, and their challenges in underwater environments are presented. A review of the underwater IWPT experiments and applications is conducted, and innovative solutions are listed. Achieving efficient and reliable UWPT technologies is not trivial, but significant progress is identified. Generally, the latest solutions exhibit efficiencies between 88% and 93% in laboratory settings, with power ratings reaching up to 1–3 kW. Based on the assessment, a power transfer within the range of 1 kW appears to be feasible and may be sufficient to operate small UUVs. However, work-class UUVs require at least a tenfold power increase. Thus, although UPWT has advanced significantly, further research is required to industrially establish these technologies. Full article
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17 pages, 3068 KiB  
Article
Effect of U-Shaped Metallic Dampers on the Seismic Performance of Steel Structures based on Endurance-Time Analysis
by Farhad Farajiani, Farzaneh Elyasigorji, Sina Elyasigorji, Mohammad Javad Moradi and Visar Farhangi
Buildings 2024, 14(5), 1368; https://doi.org/10.3390/buildings14051368 (registering DOI) - 10 May 2024
Abstract
Seismic performance of steel moment-resisting frames is investigated through the incorporation of U-shaped metallic dampers. The primary objective is to assess the effectiveness of these dampers in mitigating seismic responses by utilizing various analysis techniques. Two representative structural configurations (5 and 10-story) are [...] Read more.
Seismic performance of steel moment-resisting frames is investigated through the incorporation of U-shaped metallic dampers. The primary objective is to assess the effectiveness of these dampers in mitigating seismic responses by utilizing various analysis techniques. Two representative structural configurations (5 and 10-story) are studied in both damped and undamped states to reveal the impact of dampers on seismic response reduction. The study utilizes the endurance time analysis (ETA) method, known for its efficiency in evaluating structural seismic performance. To validate the analysis results, a benchmark comparison is made through nonlinear time history analysis (NTHA). Incremental dynamic analysis (IDA) is also conducted to assess structures’ intensity measures with respect to their damage intensity index. The findings demonstrate that U-shaped metallic dampers substantially reduce inter-story drift and story shear forces. Importantly, a close alignment between the results obtained from ETA and NTHA underscores the reliability of the former in assessing seismic performance with supplemental damping devices. Full article
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18 pages, 1274 KiB  
Article
The Role of Homogeneous Waiting Group Criteria in Patient Referrals: Views of General Practitioners and Specialists in South Tyrol, Italy
by Giuliano Piccoliori, Christian J. Wiedermann, Verena Barbieri and Adolf Engl
Healthcare 2024, 12(10), 985; https://doi.org/10.3390/healthcare12100985 (registering DOI) - 10 May 2024
Abstract
Homogeneous waiting group (HWG) criteria are central to the patient referral process, guiding primary care physicians and hospitalists in directing patient care to specialists. This cross-sectional observational study, conducted in South Tyrol, Italy, in 2023, aimed to assess the implementation and impact of [...] Read more.
Homogeneous waiting group (HWG) criteria are central to the patient referral process, guiding primary care physicians and hospitalists in directing patient care to specialists. This cross-sectional observational study, conducted in South Tyrol, Italy, in 2023, aimed to assess the implementation and impact of HWG criteria on healthcare from the perspective of general practitioners and hospital physicians. A questionnaire was developed to gain knowledge about referral practices as perceived by general practitioners and specialists. The survey included 313 participants (82 general practitioners and 231 hospital physicians) and was designed to capture a range of factors influencing the application of HWG criteria, including communication and collaboration practices. The results showed moderate levels of familiarity with HWG criteria and opinions about the need for criteria refinement among hospitalists, indicating that further education and refinement of these criteria are warranted. Both general practitioners and hospital physicians expressed dissatisfaction with the current specialist referral system, highlighting the significant gaps in effective communication and collaboration. The survey also demonstrated the influence of patient demands and waiting times on referral practices, and the need for streamlined and accessible specialist care. This study highlights the need for improvement and adaptation of HWG criteria to better meet the needs of healthcare providers and patients in South Tyrol. By addressing the identified gaps in communication, collaboration, and education related to the HWG system, the efficiency, effectiveness, and patient-centeredness of the referral process can be improved, ultimately leading to better health outcomes. Full article
(This article belongs to the Special Issue Health Professional Education and Primary Health Care)
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15 pages, 8365 KiB  
Article
Ceramic Fiber-Reinforced Polyimide Aerogel Composites with Improved Shape Stability against Shrinkage
by Wanlin Shi, Mengmeng Wan, Yating Tang and Weiwang Chen
Gels 2024, 10(5), 327; https://doi.org/10.3390/gels10050327 (registering DOI) - 10 May 2024
Abstract
Polyimide (PI) aerogels, renowned for their nano-porous structure and exceptional performance across a spectrum of applications, often encounter significant challenges during fabrication, primarily due to severe shrinkage. In this study, we innovatively incorporated ceramic fibers of varying diameters into the PI aerogel matrix [...] Read more.
Polyimide (PI) aerogels, renowned for their nano-porous structure and exceptional performance across a spectrum of applications, often encounter significant challenges during fabrication, primarily due to severe shrinkage. In this study, we innovatively incorporated ceramic fibers of varying diameters into the PI aerogel matrix to enhance the shape stability against shrinkage. The
structure of the resulting ceramic fiber-reinforced PI (CF-PI) aerogel composites as well as their performance in thermal decomposition, thermal insulation, and compression resistance were characterized. The results revealed that the CF-PI aerogel composites dried by supercritical ethanol achieved greatly reduced shrinkage as low as 5.0 vol.% and low thermal conductivity ranging from 31.2 mW·m−1·K−1 to 35.3 mW·m−1·K−1, showcasing their excellent performance in shape stability and thermal insulation. These composites also inherited the superior residue-forming ability of ceramic fibers and the robust mechanical attributes of PI, thereby exhibiting enhanced thermal stability and compression resistance. Besides, the effects of different drying conditions on the structure and properties of CF-PI aerogels were also discussed. The coupling use of supercritical ethanol drying with the addition of ceramic fibers is preferred. This preferred condition gives birth to low-shrinkage CF-PI aerogel composites, which also stand out for their integrated advantages include high thermal stability, low thermal conductivity, and high mechanical strength. These advantages attribute to CF-PI aerogel composites substantial potential for a wide range of applications, particularly as high-performance thermal insulation materials for extreme conditions. Full article
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13 pages, 588 KiB  
Article
Optimized Wide-Angle Metamaterial Edge Filters: Enhanced Performance with Multi-Layer Designs and Anti-Reflection Coatings
by Baidong Wu, James N. Monks, Liyang Yue, Andrew Hurst and Zengbo Wang
Photonics 2024, 11(5), 446; https://doi.org/10.3390/photonics11050446 (registering DOI) - 10 May 2024
Abstract
This study presents a systematic optimization of wide-angle metamaterial long-pass (LP) edge filters based on silicon nanospheres (SiNP). Multi-layered configurations incorporating SiNP-meta-films and anti-reflection coating (ARC) elements not previously considered in the literature are explored to enhance their filter performance in both stop [...] Read more.
This study presents a systematic optimization of wide-angle metamaterial long-pass (LP) edge filters based on silicon nanospheres (SiNP). Multi-layered configurations incorporating SiNP-meta-films and anti-reflection coating (ARC) elements not previously considered in the literature are explored to enhance their filter performance in both stop and pass bands. This research has successfully developed an accurate model for the effective refractive index using Kramers–Kronig relations, enabling the use of classical thin-film design software for rapid device performance optimization, which is verified by full-wave numerical software. This systematic optimization has produced highly efficient, near-shift-free long-pass metamaterial filters, evidenced by their high optical density (OD = 2.55) and low spectral shift across a wide angular range (0°–60°). These advancements herald the development of high-efficiency metamaterial optical components suitable for a variety of applications that require a consistent performance across diverse angles of incidence. Full article
(This article belongs to the Special Issue Emerging Trends in Metamaterials and Metasurfaces Research)
14 pages, 1461 KiB  
Article
Mucolytic Drugs Ambroxol and Bromhexine: Transformation under Aqueous Chlorination Conditions
by Sergey A. Sypalov, Ilya S. Varsegov, Nikolay V. Ulyanovskii, Albert T. Lebedev and Dmitry S. Kosyakov
Int. J. Mol. Sci. 2024, 25(10), 5214; https://doi.org/10.3390/ijms25105214 (registering DOI) - 10 May 2024
Abstract
Bromhexine and ambroxol are among the mucolytic drugs most widely used to treat acute and chronic respiratory diseases. Entering the municipal wastewater and undergoing transformations during disinfection with active chlorine, these compounds can produce nitrogen- and bromine-containing disinfection by-products (DBPs) that are dangerous [...] Read more.
Bromhexine and ambroxol are among the mucolytic drugs most widely used to treat acute and chronic respiratory diseases. Entering the municipal wastewater and undergoing transformations during disinfection with active chlorine, these compounds can produce nitrogen- and bromine-containing disinfection by-products (DBPs) that are dangerous for aquatic ecosystems. In the present study, primary and deep degradation products of ambroxol and bromhexine obtained in model aquatic chlorination experiments were studied via the combination of high-performance liquid and gas chromatography with high-resolution mass spectrometry. It was shown that at the initial stages, the reactions of cyclization, hydroxylation, chlorination, electrophilic ipso-substitution of bromine atoms with chlorine, and oxidative N-dealkylation occur. Along with known metabolites, a number of novel primary DBPs were tentatively identified based on their elemental compositions and tandem mass spectra. Deep degradation of bromhexine and ambroxol gives twenty-four identified volatile and semi-volatile compounds of six classes, among which trihalomethanes account for more than 50%. The specific class of bromhexine- and ambroxol-related DBPs are bromine-containing haloanilines. Seven of them, including methoxy derivatives, were first discovered in the present study. One more novel class of DBPs associated with bromhexine and ambroxol is represented by halogenated indazoles formed through dealkylation of the primary transformation products containing pyrazoline or tetrahydropyrimidine cycle in their structure. Full article
(This article belongs to the Section Molecular Pharmacology)
3 pages, 262 KiB  
Editorial
Special Issue on “Application of Power Electronics Technologies in Power System”
by Chang-Hua Lin and Jahangir Hossain
Processes 2024, 12(5), 976; https://doi.org/10.3390/pr12050976 (registering DOI) - 10 May 2024
Abstract
Over the years, all countries have agreed to alleviate the greenhouse effect and pro-mote net zero carbon emissions [...] Full article
(This article belongs to the Special Issue Application of Power Electronics Technologies in Power System)

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