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Floating breakwaters (FBs) are frequently used to protect marinas, fisheries, or other bodies of water subject to wave attacks of moderate intensity. New forms of FBs are frequently introduced and investigated in the literature as a consequence of technological advancements. In particular, a new possibility is offered by High-Density Polyethylene (HDPE) by extruding pipes of large diameters (e.g., 2.5 m in diameter) and with virtually no limit in length (hundreds of meters). By connecting two or three such pipes in a vertical layout, a novel low-cost floating breakwater with deep draft is devised. This note investigates numerically and experimentally the efficiency of this type of multi-cylindrical FBs in evaluating different geometries and aims at finding design guidelines. Due to the extraordinary length of the breakwater, the investigation is carried out in two dimensions. The 2D numerical model is based on the solution of the rigid body motion in the frequency domain, where the hydrodynamic forces are evaluated (thanks to a linear potential flow model), and the mooring forces do not include dynamic effects nor drag on the lines. The numerical predictions are compared to the results of a 1:10 scale experimental investigation. An atypical shape of the wave transmission (

k_{t}

) curve is found, with a very low minimum in correspondence with the heave resonance frequency. The results essentially point out the influence of the position of the gravity center, the stiffness, and the mutual distance among cylinders on

k_{t}

. Full article

(This article belongs to the Special Issue Coastal Engineering: Sustainability and New Technologies, 2nd Edition)

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14 pages, 1789 KiB

Open AccessArticle

4D Embedded Rotating Black Hole as a Particle Accelerator in the Presence of Magnetic Fields

by Abraão J. S. Capistrano, Carlos Henrique Coimbra-Araújo and Rita de Cássia dos Anjos

Universe 2024, 10(9), 355; https://doi.org/10.3390/universe10090355 (registering DOI) - 4 Sep 2024

Abstract

We analyze a rotating black hole (BH) in a four-dimensional space-time embedded in five-dimensional flat bulk. In Boyer–Lindquist coordinates, we use a generic extension of the Kerr metric by the line element of Gürses–Gürsey metric. We discuss their horizon properties and shadow cast which is tailored by the influence of the extrinsic curvature. By means of the model based on the Nash–Greene theorem, we analyze the Gürses–Gürsey metric embedded in five dimensions acting as a rotating “charged” BH which may be regarded as a source of ultrahigh-energy cosmic rays (UHECRs). We also show that this type of BH presents a different structure of the accretion disk which is modified by the extrinsic curvature leading to an enlargement of the photons ring and an increase in the BH’s inner shadow. In the presence of a magnetic field, our initial results suggest that such BHs may be efficient free-test particle accelerators orbiting the inner stable circular orbit (ISCO). Full article

(This article belongs to the Collection Open Questions in Black Hole Physics)

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17 pages, 862 KiB

Open AccessReview

Menstrual Dysfunction in Adolescent Female Athletes

by Valeria Calcaterra, Matteo Vandoni, Alice Bianchi, Agnese Pirazzi, Lara Tiranini, Paola Baldassarre, Marianna Diotti, Caterina Cavallo, Rossella Elena Nappi and Gianvincenzo Zuccotti

Sports 2024, 12(9), 245; https://doi.org/10.3390/sports12090245 (registering DOI) - 4 Sep 2024

Abstract

Despite the benefits of exercise on mental and physical health, excessive training loads can lead to health problems in the long term, including a wide spectrum of menstrual dysfunction (MD). This narrative review aims to analyze the relationship between physical exercise and MD in adolescent female athletes to support regular menstrual health monitoring and promote educational programs on reproductive risks. When dealing with MD in young athletes, several factors entangled with maturation of the hypothalamus–pituitary–ovarian axis should be considered. Firstly, some disciplines seem to have a higher prevalence of MD due to the high loads of training regimes and the early introduction of athletes to a competitive career. Moreover, low energy intake and a low body mass index appear to exacerbate existing MD. Lastly, disordered eating behaviors and psychological stress can contribute to MD in female athletes. The type of sport, influencing the intensity and duration of exercise, as well as individual psycho-physiological and environmental factors, may influence the role of physical activity in the manifestation of MD. Early recognition and management of MD, along with collaboration between sports organizations and health professionals, are crucial to minimize risks, ensure proper nutrition, and balance training with recovery. Keeping an open discussion on the topic may prospectively improve awareness, early diagnosis, and treatment strategies, as well as reduce injury risk and enhance sports performance. Full article

(This article belongs to the Special Issue Focus on the Health of Young Athletes and Team Sports Performance)

13 pages, 4947 KiB

Open AccessArticle

Ultra-Compact Reflective Waveguide Mode Converter Based on Slanted-Surface and Subwavelength Metamaterials

by Yanxia Zhang, Rui Feng, Bojian Shi, Xiaoxin Li, Yanyu Gao, Wenya Gao, Qi Jia, Fangkui Sun, Yongyin Cao and Weiqiang Ding

Photonics 2024, 11(9), 838; https://doi.org/10.3390/photonics11090838 - 4 Sep 2024

Abstract

Mode converter (MC) is an indispensable element in the mode multiplexing and demultiplexing system. Most previously reported mode converters have been of the transmission type, while reflective mode converters are significantly lacking. In this paper, we propose an ultra-compact reflective mode converter (RMC) structure, which comprises a slanted waveguide surface coated with a metallic film and a subwavelength metamaterial refractive index modulation region. The results demonstrate that this RMC can achieve high-performance mode conversion within an extremely short conversion length. In the two-dimensional (2D) case, the conversion length for TE₀–TE₁ is only 810 nm, and the conversion efficiency reaches to 94.1% at the center wavelength of 1.55 μm. In a three-dimensional (3D) case, the TE₀–TE₁ mode converter is only 1.14 μm, with a conversion efficiency of 92.5%. Additionally, for TE₀–TE₂ mode conversion, the conversion size slightly increases to 1.4 μm, while the efficiency reaches 94.2%. The proposed RMC demonstrates excellent performance and holds great potential for application in various integrated photonic devices. Full article

(This article belongs to the Special Issue Advanced Photonics Metamaterials and Metasurfaces: Science and Applications)

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17 pages, 9731 KiB

Open AccessArticle

CsNWD Encoding VPS62 Emerges as a Candidate Gene Conferring the Glabrous Phenotype in Cucumber

by Yuelong Zhou, Mingyuan Xu, Yong Zhou, Zhaoyang Hu and Shiqiang Liu

Agronomy 2024, 14(9), 2019; https://doi.org/10.3390/agronomy14092019 - 4 Sep 2024

Abstract

The commercial value of cucumbers is influenced by the presence of spines or trichomes on their fruit, while the trichomes found on other parts of the plant are essential for protecting the cucumber against a range of biotic and abiotic stresses. In our research, we identified a glabrous nwd mutant from EMS-induced cucumber (Cucumis sativus L.) mutant lines. This mutant displays a consistent glabrous phenotype across all plant organs. Upon analysis, it was revealed that the nwd mutation is governed by a lone recessive nuclear gene. The nwd plants show a significant reduction in both their photosynthetic capacity and chlorophyll a content when compared to the wild-type. Furthermore, there are notable changes in the antioxidant enzyme activities, soluble protein levels, and malondialdehyde content of the nwd mutant. Genotyping and MutMap approaches identified the CsNWD gene, encoding a VPS protein, as a candidate responsible for the glabrous trait. Transcriptome analysis indicated that 15 trichome-related genes exhibit significant expression changes in the nwd mutant, implying that CsNWD may regulate trichome development through interactions with these genes. This study contributes to the understanding of VPS proteins in trichome initiation and the underlying mechanisms of trichome development. Full article

(This article belongs to the Special Issue Smart Strategies and Technologies for Sustainability and Biodiversity in Herbaceous and Horticultural Crops—2nd Edition)

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12 pages, 1306 KiB

Open AccessCommunication

Deep Integration of Fiber-Optic Communication and Sensing Systems using Forward-Transmission Distributed Vibration Sensing and On–Off Keying

by Runlong Zhu, Xing Rao, Shangwei Dai, Ming Chen, Guoqiang Liu, Hanjie Liu, Rendong Xu, Shuqing Chen, George Y. Chen and Yiping Wang

Sensors 2024, 24(17), 5758; https://doi.org/10.3390/s24175758 - 4 Sep 2024

Abstract

The deep integration of communication and sensing technology in fiber-optic systems has been highly sought after in recent years, with the aim of rapid and cost-effective large-scale upgrading of existing communication cables in order to monitor ocean activities. As a proof-of-concept demonstration, a high-degree of compatibility was shown between forward-transmission distributed fiber-optic vibration sensing and an on–off keying (OOK)-based communication system. This type of deep integration allows distributed sensing to utilize the optical fiber communication cable, wavelength channel, optical signal and demodulation receiver. The addition of distributed sensing functionality does not have an impact on the communication performance, as sensing involves no hardware changes and does not occupy any bandwidth; instead, it non-intrusively analyzes inherent vibration-induced noise in the data transmitted. Likewise, the transmission of communication data does not affect the sensing performance. For data transmission, 150 Mb/s was demonstrated with a BER of 2.8 × 10⁻⁷ and a Q_dB of 14.1. For vibration sensing, the forward-transmission method offers distance, time, frequency, intensity and phase-resolved monitoring. The limit of detection (LoD) is 8.3 pε/Hz^1/2 at 1 kHz. The single-span sensing distance is 101.3 km (no optical amplification), with a spatial resolution of 0.08 m, and positioning accuracy can be as low as 10.1 m. No data averaging was performed during signal processing. The vibration frequency range tested is 10–1000 Hz. Full article

(This article belongs to the Section Optical Sensors)

31 pages, 4308 KiB

Open AccessArticle

Sustainable Protection Strategies for Traditional Villages Based on a Socio-Ecological Systems Spatial Pattern Evaluation: A Case Study from Jinjiang River Basin in China

by Xue Jiang, Shuhan Man, Xianglong Zhu, Hongyu Zhao and Tianjiao Yan

Sustainability 2024, 16(17), 7700; https://doi.org/10.3390/su16177700 - 4 Sep 2024

Abstract

Traditional villages have reached milestones in developing a living culture, politics, economy, and society, among other aspects, while acting as important carriers of agricultural culture formed by long-term interactions between humans and nature. Unfortunately, traditional villages could disappear with the advent of urbanization. Therefore, this study enhances the accuracy of traditional village classification protection work by examining traditional villages in the Jinjiang River Basin in Quanzhou, China. A spatial pattern is extracted for the socio-ecological systems (SES) prototype of traditional villages, and an SES classification protection system is constructed based on a prototype analysis. Given the evaluation results, a K-means cluster analysis is applied to establish the SES sustainability levels for six types of traditional villages. After adjusting the types according to the principles of sustainability, equilibrium, and individual cases, six SES system types are identified: SES decay and shrinkage (Type 1), SES fusion and development (Type 2), SES ecological decline (Type 3), SES social decline (Type 4), SES ecological conservation (Type 5), and SES extensive development (Type 6). This system provides a quantitative analysis method to classify and protect concentrated and contiguous traditional villages. It also helps facilitate a better understanding of local rural society, economy, and culture, especially a deeper understanding of the interactions between humans and the rural environment. Full article

(This article belongs to the Special Issue Sustainable Urban and Rural Land Planning and Utilization)

13 pages, 765 KiB

Open AccessReview

Cisplatin Resistance and Metabolism: Simplification of Complexity

by Nikolay V. Pervushin, Maria A. Yapryntseva, Mikhail A. Panteleev, Boris Zhivotovsky and Gelina S. Kopeina

Cancers 2024, 16(17), 3082; https://doi.org/10.3390/cancers16173082 - 4 Sep 2024

Abstract

Cisplatin is one of the most well-known anti-cancer drugs and has demonstrated efficacy against numerous tumor types for many decades. However, a key challenge with cisplatin, as with any chemotherapeutic agent, is the development of resistance with a resultant loss of efficacy. This resistance is often associated with metabolic alterations that allow insensitive cells to divide and survive under treatment. These adaptations could vary greatly among different tumor types and may seem questionable and incomprehensible at first glance. Here we discuss the disturbances in glucose, lipid, and amino acid metabolism in cisplatin-resistant cells as well as the roles of ferroptosis and autophagy in acquiring this type of drug intolerance. Full article

(This article belongs to the Section Molecular Cancer Biology)

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22 pages, 63144 KiB

Open AccessArticle

Spatiotemporal Evaluation of the Coupling Relationship between Public Service Facilities and Population: A Case Study of Wuhan Metropolitan Area, Central China

by Kaixuan Liang, You Zou and Guiyuan Li

Sustainability 2024, 16(17), 7698; https://doi.org/10.3390/su16177698 - 4 Sep 2024

Abstract

Metropolitan areas are important regions with a high concentration of population and public service facilities. The coupling coordination between public service facilities and population plays an important role in the sustainable development of economy and society. However, previous studies have focused on a few core cities, effectively identifying areas with weak coordination of public services and currently lacking corresponding information support and paradigms at the regional scale. Taking the Wuhan Metropolitan Area as an example, this paper strengthens the concern about the spatiality and locality of public service facilities in the region;, applies the improved CRITIC method and coupling coordination model to study the spatiotemporal distribution characteristics of public service facilities at the county and grid levels by using multisource data, and evaluates the intercity differences and dynamic changes of coupling coordination relationships between public service facilities and population. The findings are as follows: (1) Wuhan was the core of public service facilities in the metropolitan area, and a continuous high-level coordinated distribution was gradually developed on the east-west axis from 2016 to 2022; (2) there were differences in the coupling coordination degree of different types of facilities, among which the imbalance between the supply and demand of elderly care facilities was obvious; and (3) the coupling coordination degree of facilities in the Wu-E-Huang-Huang core development area was relatively high. Finally, we summarize the development stages of the coupling coordination between the facilities and population in the Wuhan Metropolitan Area and obtain the typical development characteristics. The research results could provide scientific support for planning decisions. Full article

(This article belongs to the Section Sustainable Urban and Rural Development)

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11 pages, 9625 KiB

Open AccessArticle

Running-In of DLC–Third Body or Transfer Film Formation

by Joachim Faller and Matthias Scherge

Lubricants 2024, 12(9), 314; https://doi.org/10.3390/lubricants12090314 - 4 Sep 2024

Abstract

Amorphous carbon coatings are widely used due to their beneficial friction and wear characteristics. A detailed understanding of their behavior during running-in, apart from model tribosystems, has yet to be obtained. Multiple analytical methods were used to detect the physical and chemical changes in a ta-C coating and its thermally sprayed, metallic counterpart after a running-in procedure with pin-on-disk experiments. Both coatings exhibited changes in their surface and near-surface chemistry. The mechanisms in and on the metallic coating were identified to be a mixture of the third-body type, with the formation of gradients in the microstructure and chemistry and an additional carbon-rich tribofilm formation on top. The ta-C coating’s changes in chemistry with sp² enrichment and lubricant element inclusions proved to be too complex to allocate them to tribofilm or third-body formation. Full article

(This article belongs to the Special Issue Tribology in Germany: Latest Research and Development)

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29 pages, 6699 KiB

Open AccessArticle

Optimal Signal Wavelengths for Underwater Optical Wireless Communication under Sunlight in Stratified Waters

by Tharuka Govinda Waduge, Boon-Chong Seet and Kay Vopel

J. Sens. Actuator Netw. 2024, 13(5), 54; https://doi.org/10.3390/jsan13050054 - 4 Sep 2024

Abstract

Underwater optical wireless communication (UOWC) is a field of research that has gained popularity with the development of unmanned underwater vehicle (UUV) technologies. Its utilization is crucial in offshore industries engaging in sustainable alternatives for food production and energy security. Although UOWC can meet the high data rate and low latency requirements of underwater video transmission for UUV operations, the links that enable such communication are affected by the inhomogeneous light attenuation and the presence of sunlight. Here, we present how the underwater spectral distribution of the light field can be modeled along the depths of eight stratified oceanic water types. We considered other established models, such as SPCTRL2, Haltrin’s single parameter model for inherent optical properties, and a model for the estimation of the depth distribution of chlorophyll-a, and present insights based on transmission wavelength for the maximum signal-to-noise ratio (SNR) under different optical link parameter combinations such as beam divergence and transmit power under “daytime” and “nighttime” conditions. The results seem to challenge the common notion that the blue-green spectrum is the most suitable for underwater optical communication. We highlight a unique relationship between the transmission wavelength for the optimal SNR and the link parameters and distance, which varies with depth depending on the type of oceanic water stratification. Our analyses further highlighted potential implications for solar discriminatory approaches and strategies for routing in cooperative optical wireless networks in the photic region. Full article

(This article belongs to the Section Communications and Networking)

15 pages, 529 KiB

Open AccessArticle

Integrated Study of Canine Mammary Tumors Histopathology, Immunohistochemistry, and Cytogenetic Findings

by Tiago Ferreira, Maria Miranda, Rosário Pinto-Leite, João F. Mano, Rui Medeiros, Paula A. Oliveira and Adelina Gama

Vet. Sci. 2024, 11(9), 409; https://doi.org/10.3390/vetsci11090409 - 4 Sep 2024

Abstract

Cancer is a complex pathological condition associated with substantial rates of mortality and morbidity in both humans and animals. Mammary gland tumors in intact female dogs are the most prevalent neoplasms. Surgical intervention remains the primary treatment choice. Alternative therapeutic options have emerged, with histopathological examination being fundamental to confirm the diagnosis and to decide the best therapy. This research focused on the clinicopathological, immunohistochemical, and cytogenetic aspects of canine mammary tumors (CMTs). Most of the animals were mixed-breed, with the majority being older than seven years, and only 16.7% had been spayed before surgery. Caudal abdominal and inguinal mammary glands were the most affected, with regional mastectomy being the predominant treatment (75.0%). Of all the tumors, 29.1% were benign, while 70.9% were malignant. Complex adenoma was the most common benign tumor, whereas tubulopapillary carcinoma was the most common malignant type. Grade III tumors (17.6%) were the least encountered, while grades I and II exhibited a similar prevalence (41.2%). All the carcinomas were classified as luminal, and cytogenetics analysis demonstrated a high chromosomal instability with significant aneuploidy observed in all cases and polyploidy detected in 62.5%. This study holds significance as canine and human breast cancers share similar characteristics, suggesting that dogs could be a valuable model for human breast cancer research. Further studies with larger sample sizes are needed to enhance our understanding of CMTs. Full article

(This article belongs to the Special Issue New Insights into Canine Tumors)

18 pages, 499 KiB

Open AccessArticle

Farm-Level Risk Factors for Lameness in 659 German Dairy Herds Kept in Loose Housing Systems

by Anna Tillack, Roswitha Merle, Kerstin-Elisabeth Müller, Martina Hoedemaker, Katharina Charlotte Jensen, Andreas W. Oehm, Marcus Klawitter and Annegret Stock

Animals 2024, 14(17), 2578; https://doi.org/10.3390/ani14172578 - 4 Sep 2024

Abstract

Six hundred fifty-nine farms in three regions of Germany (North: n = 240, East: n = 247, and South: n = 172) were included in the study, which aims at determining the association of management-related risk factors with farm-level lameness in German dairy herds. For each risk factor, a generalised linear regression model with negative binomial distribution and logit link was built. Results showed that cows housed in deep-bedded cubicles had a lower risk of being lame than cows housed in other cubicle types. A larger cubicle width was associated with a lower risk of being lame. Feeding a total mixed ration was associated with lower lameness prevalence (compared to feeding a partial mixed ration or single components). For first lactation cows, lameness assessment performed daily (compared to less than daily) and during other work tasks (compared to lameness assessment as a separate work task) were associated with lower risk for lameness. Finally, the present study provided evidence for crucial associations of management-related risk factors with lameness in German dairy cows, especially in the fields of cubicle design, feeding management, and lameness assessment. Full article

(This article belongs to the Special Issue Step by Step: Detection, Diagnosis, Control and Treatment of Ruminant Lameness and Foot Diseases)

22 pages, 295 KiB

Open AccessArticle

Ostrowski-Type Inequalities for Functions of Two Variables in Banach Spaces

by Muhammad Amer Latif and Ohud Bulayhan Almutairi

Mathematics 2024, 12(17), 2748; https://doi.org/10.3390/math12172748 - 4 Sep 2024

Abstract

In this paper, we offer Ostrowski-type inequalities that extend the findings that have been proven for functions of one variable with values in Banach spaces, conducted in a remarkable study by Dragomir, to functions of two variables containing values in the product Banach spaces. Our findings are also an extension of several previous findings that have been established for functions of two variable functions. Prior studies on Ostrowski-type inequalities incriminated functions that have values in Banach spaces or Hilbert spaces. This study is unique and significant in the field of mathematical inequalities, and specifically in the study of Ostrowski-type inequalities, because they have been established for functions having values in a product of two Banach spaces. Full article

(This article belongs to the Special Issue Mathematical Analysis and Functional Analysis and Their Applications)

11 pages, 1253 KiB

Open AccessArticle

Association between Flexibility, Measured with the Back-Scratch Test, and the Odds of Oxytocin Administration during Labour and Caesarean Section

by Virginia A. Aparicio, Nuria Marín-Jiménez, Jose Castro-Piñero, Marta Flor-Alemany, Irene Coll-Risco and Laura Baena-García

J. Clin. Med. 2024, 13(17), 5245; https://doi.org/10.3390/jcm13175245 - 4 Sep 2024

Abstract

Objective: This study explored whether assessing flexibility levels in clinical settings might predict the odds of oxytocin administration and caesarean section to stimulate labour. Methods: Pregnant women from the GESTAFIT Project (n = 157), participated in this longitudinal study. Maternal upper-body flexibility was assessed at 16 gestational weeks (g.w.) through the Back-scratch test. Clinical data, including oxytocin administration and type of birth, were registered from obstetric medical records. Results: Pregnant women who required oxytocin administration or had caesarean sections showed lower flexibility scores (p < 0.05 and p < 0.01, respectively). The receiver operating characteristic curve analysis showed that the Back-scratch test was able to detect the need for oxytocin administration ((area under the curve [AUC] = 0.672 (95% confidence interval [CI]: 0.682 (95% CI: 0.59–0.78, p = 0.001)). The AUC to establish the ability of flexibility to discriminate between vaginal and caesarean section births was 0.672 (95% CI: 0.60–0.77, p = 0.002). A Back-scratch test worse than 4 centimetres was associated with a ~5 times greater increased odds ratio of requiring exogenous oxytocin administration (95% CI: 2.0–11.6, p = 0.001) and a ~4 times greater increased odds ratio of having a caesarean section (95% CI: 1.7–10.2, p = 0.002). Conclusions: These findings suggest that lower flexibility levels at the 16th g.w. discriminates between pregnant women who will require oxytocin and those who will not, and those with a greater risk of a caesarean section than those with a vaginal birth. Pregnant women below the proposed Back-scratch test cut-offs at 16th g.w. might specifically benefit from physical therapies that include flexibility training. Full article

(This article belongs to the Special Issue Clinical Risks and Perinatal Outcomes in Pregnancy and Childbirth)

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