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Search Results (303)

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Keywords = new step-up converter

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39 pages, 1310 KiB  
Article
How Agricultural Innovation Talents Influence County-Level Industrial Structure Upgrading: A Knowledge-Empowerment Perspective
by Lizhan Lv and Feng Dai
Agriculture 2025, 15(14), 1500; https://doi.org/10.3390/agriculture15141500 - 12 Jul 2025
Viewed by 393
Abstract
Upgrading the industrial structure is an essential step for economic growth and the transformation of old and new development drivers. Counties situated at the rural–urban interface hold a comparative advantage in industrial upgrading compared to cities, converting agricultural resource dividends into economic value. [...] Read more.
Upgrading the industrial structure is an essential step for economic growth and the transformation of old and new development drivers. Counties situated at the rural–urban interface hold a comparative advantage in industrial upgrading compared to cities, converting agricultural resource dividends into economic value. However, whether agricultural innovation talent can facilitate this process requires further investigation. Based on a sample of 1771 Chinese counties, this study employs a quasi-natural experiment using China’s “World-Class Disciplines” construction program in agriculture and establishes a difference-in-differences (DID) model to examine the impact of agricultural innovation talent on county-level industrial structure upgrading. The results show that agricultural innovation talent significantly promotes industrial upgrading, with this effect being more pronounced in counties with smaller urban–rural income gaps, greater household savings, and higher levels of industrial sophistication. Spatial spillover effects are also evident, indicating regional knowledge diffusion. Knowledge empowerment emerges as the core mechanism: agricultural innovation talent drives industrial convergence, responds to supply–demand dynamics, and integrates digital and intelligent elements through knowledge creation, dissemination, and application, thereby supporting county-level industrial upgrading. The findings highlight the necessity of establishing world-class agricultural research and talent incubation platforms, particularly emphasizing the supportive role of universities and the knowledge-driven contributions of agricultural innovation talents to county development. Full article
(This article belongs to the Section Agricultural Economics, Policies and Rural Management)
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13 pages, 603 KiB  
Communication
Synthesis and In Vitro Pharmacological Evaluation of 5,8-Dideaza Analogs of Methotrexate
by Marta Abellán-Flos, Charles Skarbek, Dáire J. Gibbons, Estelle Rascol, Ainhoa García and Raphaël Labruère
Molecules 2025, 30(13), 2772; https://doi.org/10.3390/molecules30132772 - 27 Jun 2025
Viewed by 293
Abstract
This study describes the synthesis of a series of dideaza analogs of methotrexate and their preliminary pharmacological and metabolic evaluation. The 5,8-dideazamethotrexate was efficiently obtained in five steps using a new synthetic route. Oxygenated and thiolated analogs of dideazamethotrexate were prepared following the [...] Read more.
This study describes the synthesis of a series of dideaza analogs of methotrexate and their preliminary pharmacological and metabolic evaluation. The 5,8-dideazamethotrexate was efficiently obtained in five steps using a new synthetic route. Oxygenated and thiolated analogs of dideazamethotrexate were prepared following the devised pathway. Their cytotoxicity was studied in the A549 lung cancer cell line, as well as their DHFR dihydrofolate reductase inhibition activity and in vitro metabolism. The two new analogs showed strong activity on cancer cells and the enzymatic target. These compounds were not metabolized, a clear advantage over methotrexate, which is rapidly converted to the toxic metabolite 7-hydroxymethotrexate. Full article
(This article belongs to the Section Medicinal Chemistry)
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20 pages, 1703 KiB  
Article
A GIS-Based Approach to Land Take Monitoring and Actual Land Use Analysis
by Peter Lamovec, Katarina Kuk, Barbara Černič, Tomaž Černe and Ines Lupše
Land 2025, 14(7), 1322; https://doi.org/10.3390/land14071322 - 21 Jun 2025
Viewed by 604
Abstract
In September 2023, the European Commission approved a proposal for a Directive on Soil Monitoring and Resilience, representing a significant step forward in the EU’s efforts toward more sustainable land use management. The proposal mandates the monitoring of land take and soil sealing [...] Read more.
In September 2023, the European Commission approved a proposal for a Directive on Soil Monitoring and Resilience, representing a significant step forward in the EU’s efforts toward more sustainable land use management. The proposal mandates the monitoring of land take and soil sealing indicators but does not specify the method for determining their values. Instead, it allows for the use of scientific literature or other publicly available methods. This study presents a methodology based on GIS analyses for monitoring artificial land and the land take indicator. A quantitative analysis of two municipalities in the Podravska region in Slovenia is complemented by a qualitative assessment of detailed actual land use in these municipalities. The results show that the annual land take rate in the period 2019–2022 amounted to 881.96 m2/year·km2 in the municipality of Maribor and 731.31 m2/year·km2 in the municipality of Kungota. If current trends continue, the extent of (semi-)natural land will continue to decline, which is considered unsustainable. Further analysis reveals that the expansion of artificial land in these areas is mainly due to the development of new residential land, accounting for 60.8% of newly converted land in the municipality of Maribor and 50.2% in the municipality of Kungota during the period under review. As the results point to unsustainable land management, the study is aimed at policymakers and public authorities, highlighting the urgent need to limit the conversion of (semi-)natural land and to initiate land restoration measures as compensation for new land take. It may also be of interest to scientists and researchers developing methodologies for monitoring artificial land and refining land take indicators. Full article
(This article belongs to the Special Issue Spatial-Temporal Evolution Analysis of Land Use)
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27 pages, 3479 KiB  
Article
A Hybrid IVFF-AHP and Deep Reinforcement Learning Framework for an ATM Location and Routing Problem
by Bahar Yalcin Kavus, Kübra Yazici Sahin, Alev Taskin and Tolga Kudret Karaca
Appl. Sci. 2025, 15(12), 6747; https://doi.org/10.3390/app15126747 - 16 Jun 2025
Viewed by 632
Abstract
The impact of alternative distribution channels, such as bank Automated Teller Machines (ATMs), on the financial industry is growing due to technological advancements. Investing in ideal locations is critical for new ATM companies. Due to the many factors to be evaluated, this study [...] Read more.
The impact of alternative distribution channels, such as bank Automated Teller Machines (ATMs), on the financial industry is growing due to technological advancements. Investing in ideal locations is critical for new ATM companies. Due to the many factors to be evaluated, this study addresses the problem of determining the best location for ATMs to be deployed in Istanbul districts by utilizing the multi-criteria decision-making framework. Furthermore, the advantages of fuzzy logic are used to convert expert opinions into mathematical expressions and incorporate them into decision-making processes. For the first time in the literature, a model has been proposed for ATM location selection, integrating clustering and the interval-valued Fermatean fuzzy analytic hierarchy process (IVFF-AHP). With the proposed methodology, the districts of Istanbul are first clustered to find the risky ones. Then, the most suitable alternative location in this district is determined using IVFF-AHP. After deciding the ATM locations with IVFF-AHP, in the last step, a Double Deep Q-Network Reinforcement Learning model is used to optimize the Cash in Transit (CIT) vehicle route. The study results reveal that the proposed approach provides stable, efficient, and adaptive routing for real-world CIT operations. Full article
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23 pages, 1202 KiB  
Article
Harnessing Pyrolysis for Industrial Energy Autonomy and Sustainable Waste Management
by Dimitrios-Aristotelis Koumpakis, Alexandra V. Michailidou and Christos Vlachokostas
Energies 2025, 18(12), 3041; https://doi.org/10.3390/en18123041 - 8 Jun 2025
Viewed by 1149
Abstract
This study describes the step-by-step development of a simplified system which can be implemented in industrial facilities with the help of their own surplus of plastic waste, mainly packaging waste, to reach a level of energy autonomy or semi-autonomy. This waste is converted [...] Read more.
This study describes the step-by-step development of a simplified system which can be implemented in industrial facilities with the help of their own surplus of plastic waste, mainly packaging waste, to reach a level of energy autonomy or semi-autonomy. This waste is converted to about 57,500 L of synthetic pyrolysis oil, which can then be used to power industries, being fed into a Combined Heat and Power system. To achieve this goal, the design has hydrocarbon stability at elevated temperature and restricted oxygen exposure, so that they can be converted to new products. Pyrolysis is a key process which causes thermo-chemical changes—ignition and vaporization. The research outlines the complete process of creating a basic small-scale pyrolysis system which industrial facilities can use to generate energy from their plastic waste. The proposed unit processes 360 tons of plastic waste yearly to produce 160 tons of synthetic pyrolysis oil which enables the generation of 500 MWh of electricity and 60 MWh of heat. The total investment cost is estimated at EUR 41,000, with potential annual revenue of up to EUR 45,000 via net metering. The conceptual design proves both environmental and economic viability by providing a workable method for decentralized waste-to-energy solutions for Small and Medium-sized Enterprises. Full article
(This article belongs to the Section B: Energy and Environment)
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20 pages, 1834 KiB  
Article
Conversion of Sewage Sludge with Combined Pyrolysis and Gasification via the Enhanced Carbon-To-X-Output Technology
by Wolfgang Gebhard, Sebastian Zant, Johannes Neidel, Andreas Apfelbacher and Robert Daschner
Biomass 2025, 5(2), 28; https://doi.org/10.3390/biomass5020028 - 17 May 2025
Viewed by 1346
Abstract
Sustainably produced hydrogen has the potential to substitute fossil fuels and significantly reduce CO2 emissions. Fraunhofer UMSICHT develops a new thermochemical conversion technology to gasify ash-rich biogenic residues and waste materials that are difficult to treat with conventional gasifiers, enabling their conversion [...] Read more.
Sustainably produced hydrogen has the potential to substitute fossil fuels and significantly reduce CO2 emissions. Fraunhofer UMSICHT develops a new thermochemical conversion technology to gasify ash-rich biogenic residues and waste materials that are difficult to treat with conventional gasifiers, enabling their conversion into higher-quality energy carriers such as hydrogen and syngas. Ash-rich feedstocks are difficult to convert in conventional gasification methods, as they tend to agglomerate and form slag, leading to blockages in the reactor and process disturbances. In this experimental study, hydrogen-rich syngas is produced from biogenic residual and waste materials (sewage sludge) using the Enhanced Carbon-To-X-Output (EXO) process. The EXO process is a three-stage thermochemical conversion process that consists of a combination of multi-stage gasification and a subsequent reforming step. The influence of temperature in the reforming step on the gas composition and hydrogen yield is systematically investigated. The reformer temperature of the process is gradually increased from 500 °C to 900 °C. The feedstock throughput of the pilot plant is approximately 10 kg/h. The results demonstrate that the temperature of the reforming step has a significant impact on the composition and yield of syngas as well as the hydrogen yield. By increasing the reformer temperature, the syngas yield could be enhanced. The hydrogen yield increased from 15.7 gH2/kgFeed to 35.7 gH2/kgFeed. The hydrogen content in the syngas significantly increased from 23.6 vol.% to 39 vol.%. The produced syngas can be effectively utilized for sustainable hydrogen production, as a feedstock for subsequent syntheses, or for power and heat generation. Full article
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19 pages, 7639 KiB  
Article
Triple Filtering of Terrain Conductivity Data for Precise Tracing of Underground Utilities
by Mohamed Rashed, Abdulaziz Alqarawy, Nassir Al-Amri, Riyadh Halawani, Milad Masoud and Maged El Osta
Geosciences 2025, 15(5), 179; https://doi.org/10.3390/geosciences15050179 - 15 May 2025
Viewed by 298
Abstract
Terrain conductivity meters (TCMs) are efficient devices for different sorts of subsurface investigations, including detecting and tracing buried utilities, such as metallic pipes and cables. However, data collected using TCMs are usually ambiguous and hard to interpret. This ambiguity originates from the complex [...] Read more.
Terrain conductivity meters (TCMs) are efficient devices for different sorts of subsurface investigations, including detecting and tracing buried utilities, such as metallic pipes and cables. However, data collected using TCMs are usually ambiguous and hard to interpret. This ambiguity originates from the complex shape of apparent conductivity anomalies, the influence of irrelevant conductive bodies, and the interference of random noise with the collected data. To overcome this ambiguity and produce more interpretable apparent conductivity maps, a three-step filtering routine is proposed and tested using different real datasets. The filtering routine begins with applying a Savitzky–Golay (SG) filter to reduce the effect of random noise. This is followed by a modified rolling ball (MRB) filter to convert the complex M-shape of the anomaly into a single trough pointing to the underground utility. Finally, a virtual resolution enhancement (VRE) filter is applied to enhance the pinpointing apex of the trough. The application of the proposed filtering routine to apparent conductivity data collected using different terrain conductivity meters over different utilities in different urban environments shows a significant improvement of the data and an effective ability to reveal masked underground utilities. The proposed triple filtering routine can be a starting point for a new generation of TCMs with a built-in operation mode for instantaneous delineation and characterization of underground utilities in real time. Full article
(This article belongs to the Section Geophysics)
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15 pages, 2826 KiB  
Article
Electrochemical Looping Green Hydrogen Production by Using Water Electrochemically Treated as a Raw Material for the Electrolyzer
by Mayra K. Sales Monteiro, Jussara C. Cardozo, Aruzza M. de Morais Araújo, Amanda D. Gondim, Tabata N. Feijoó, Luis D. Loor-Urgilés, Carlos A. Martínez-Huitle, Marco A. Quiroz and Elisama V. dos Santos
Catalysts 2025, 15(5), 447; https://doi.org/10.3390/catal15050447 - 2 May 2025
Cited by 1 | Viewed by 814
Abstract
In this study, the applicability of an integrated-hybrid process was performed in a divided electrochemical cell for removing organic matter from a polluted effluent with simultaneous production of green H2. After that, the depolluted water was reused, for the first time, [...] Read more.
In this study, the applicability of an integrated-hybrid process was performed in a divided electrochemical cell for removing organic matter from a polluted effluent with simultaneous production of green H2. After that, the depolluted water was reused, for the first time, in the cathodic compartment once again, in the same cell to be a viable environmental alternative for converting water into energy (green H2) with higher efficiency and reasonable cost requirements. The production of green H2 in the cathodic compartment (Ni-Fe-based steel stainless (SS) mesh as cathode), in concomitance with the electrochemical oxidation (EO) of wastewater in the anodic compartment (boron-doped diamond (BDD) supported in Nb as anode), was studied (by applying different current densities (j = 30, 60 and 90 mA cm−2) at 25 °C) in a divided-membrane type electrochemical cell driven by a photovoltaic (PV) energy source. The results clearly showed that, in the first step, the water anodically treated by applying 90 mA cm−2 for 180 min reached high-quality water parameters. Meanwhile, green H2 production was greater than 1.3 L, with a Faradaic efficiency of 100%. Then, in a second step, the water anodically treated was reused in the cathodic compartment again for a new integrated-hybrid process with the same electrodes under the same experimental conditions. The results showed that the reuse of water in the cathodic compartment is a sustainable strategy to produce green H2 when compared to the electrolysis using clean water. Finally, two implied benefits of the proposed process are the production of green H2 and wastewater cleanup, both of which are equally significant and sustainable. The possible use of H2 as an energetic carrier in developing nations is a final point about sustainability improvements. This is a win-win solution. Full article
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18 pages, 1682 KiB  
Article
Optimisation for Sustainable Supply Chain of Aviation Fuel, Green Diesel, and Gasoline from Microalgae Cultivated in Sugarcane Vinasse
by Jorge Eduardo Infante Cuan, Víctor Fernández García, Reynaldo Palacios and Adriano Viana Ensinas
Processes 2025, 13(5), 1326; https://doi.org/10.3390/pr13051326 - 26 Apr 2025
Viewed by 685
Abstract
The development of new technologies for the production of renewable energy is fundamental to reducing greenhouse gas emissions. Therefore, the search for new energy generation methods that are environmentally responsible, socially rational, and economically viable is gaining momentum in order to mitigate carbon [...] Read more.
The development of new technologies for the production of renewable energy is fundamental to reducing greenhouse gas emissions. Therefore, the search for new energy generation methods that are environmentally responsible, socially rational, and economically viable is gaining momentum in order to mitigate carbon footprint. The aviation sector is responsible for a significant fraction of greenhouse gas emissions; for this reason, the decarbonisation of this sector must be investigated using biorefinery models. This study presents a mixed-integer linear programming (MILP) model for optimising the design and configuration of the supply chain in different states of Brazil for the production of sustainable aviation fuel (SAF) and green diesel and gasoline, using microalgae cultivated in sugarcane vinasse as the raw material. The technology of hydrothermal liquefaction was assessed in terms of its capacity to convert microalgae without need for the energy-intensive drying step. The MILP model was developed in the LINGO v.20 software using a library of physical and economic process models. We consider the selection of processes based on the object of total minimum cost, with optimal production plant scaling and regional supply chain design, including an assessment of resources and final product distribution. A case study was implemented in Brazil, considering different regions of the country and its local demands for fuels. São Paulo is the most profitable state, with a cash flow of 1071.09 and an IRR of 36.19%, far outperforming the rest. Transport emissions alone represent between 0.6 and 8.6% of emissions generated by the model. The costs of raw materials, mainly hydrogen (57%) and electricity (27%) represent the main costs evaluated in the model. The production cost (MUS$/TJ biofuel) is in the range of 0.009–0.011. Finally, changes in the cost of electricity have the greatest impact on the model. Full article
(This article belongs to the Special Issue Design and Application of Microalgal Bioreactors)
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16 pages, 7598 KiB  
Article
Vehicle Height Lifting Strategy Based on Double-Vector Control of Permanent Magnet Synchronous Linear Motor
by Cheng Wang and Jialing Yao
Electronics 2025, 14(8), 1515; https://doi.org/10.3390/electronics14081515 - 9 Apr 2025
Viewed by 449
Abstract
Conventional active vehicle height control systems predominantly employ hydraulic or pneumatic suspension mechanisms. Although these established approaches have achieved widespread adoption in automotive applications, they remain fundamentally constrained by three critical drawbacks: (1) inadequate dynamic response characteristics, (2) high energy consumption, and (3) [...] Read more.
Conventional active vehicle height control systems predominantly employ hydraulic or pneumatic suspension mechanisms. Although these established approaches have achieved widespread adoption in automotive applications, they remain fundamentally constrained by three critical drawbacks: (1) inadequate dynamic response characteristics, (2) high energy consumption, and (3) inherent mechanical complexity. The ongoing electrification revolution in vehicle technologies has spurred significant research interest in linear electromagnetic suspension systems. Nevertheless, their practical implementation encounters dual technical barriers: (a) complex multi-phase motor configurations requiring precise coordination, and (b) substantial thrust ripple generation under dynamic operating conditions. To address these critical limitations, our research proposes a novel motor structure, known as the flat rectangular slot structure, which offers advantages such as simple installation and high thrust with low current. Additionally, we have designed a double-vector control strategy for the motor control section, which modifies the finite-set model predictive control and enhances the accuracy of the model’s calculations. By integrating the vehicle model, we have developed a multi-layer hierarchical control strategy for the vehicle height controller. In the first layer, a PI controller is used to convert the target height into current, which is then input into the value function. In the second layer, we improve the control strategy for the linear motor by optimizing the finite-set model predictive control through the double-vector control. Through multi-step predictive calculations, we determine the optimal sector, enabling the motor to receive the corresponding control force. In the third layer, the motor thrust is input into the vehicle model to achieve closed-loop control of the vehicle body. Finally, we conduct simulation verification of the proposed control strategy. The simulation results indicate that the double-vector control significantly reduces the fluctuation in the sprung mass displacement by approximately 70% compared to single-vector control, the response speed is increased by approximately 20%, and the thrust required to achieve the target vehicle height is reduced by 5.7%. Therefore, the proposed double-vector control strategy can significantly enhance the stability of the automotive electronic control suspension, opening up new research avenues for the study of suspension stability control and energy saving in vehicles. Full article
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30 pages, 13767 KiB  
Article
A Novel Transformerless Soft-Switching Symmetrical Bipolar Power Converter: Analysis, Design, Simulation and Validation
by Cristian Díaz-Martín, Eladio Durán Aranda, Fernando Alves da Silva and Sérgio André
Electronics 2025, 14(7), 1434; https://doi.org/10.3390/electronics14071434 - 2 Apr 2025
Viewed by 522
Abstract
In order to obtain acceptable efficiencies, hard-switching techniques and the converters that implement them must operate at relatively low frequencies (tens of kilohertz), which translate into converters of large size, weight, and volume, and therefore higher cost. To improve these characteristics, this work [...] Read more.
In order to obtain acceptable efficiencies, hard-switching techniques and the converters that implement them must operate at relatively low frequencies (tens of kilohertz), which translate into converters of large size, weight, and volume, and therefore higher cost. To improve these characteristics, this work introduces a new transformerless MHz-range DC–DC converter that provides symmetrical bipolar outputs. The developed topology uses a single grounded switch, achieves soft switching (ZVS) over a wide load range, and does not require the use of floating or isolated controllers, reducing cost, size, and complexity. The output voltages are self-regulated to maintain the same value, ensuring balanced bipolar operation. A comprehensive analysis, design, sizing, simulation, implementation and testing are provided on a 150 W prototype operating at a switching frequency of 1 MHz, with step-up and step-down capability and implemented with GaN FET. The evaluated configuration shows an efficiency close to 90% and high power density, making it suitable for compact designs in a variety of applications requiring reliable power management and high efficiency such as lighting, electric vehicles, or auxiliary power supplies. Full article
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19 pages, 8720 KiB  
Article
High Step-Up Interleaved DC–DC Converter with Voltage-Lift Capacitor and Voltage Multiplier Cell
by Shin-Ju Chen, Sung-Pei Yang, Chao-Ming Huang and Po-Yuan Hu
Electronics 2025, 14(6), 1209; https://doi.org/10.3390/electronics14061209 - 19 Mar 2025
Viewed by 783
Abstract
In this article, a new high step-up interleaved DC–DC converter is presented for renewable energy systems. The converter circuit is based on the interleaved two-phase boost converter and integrates a voltage-lift capacitor and a voltage multiplier cell. A high voltage gain of the [...] Read more.
In this article, a new high step-up interleaved DC–DC converter is presented for renewable energy systems. The converter circuit is based on the interleaved two-phase boost converter and integrates a voltage-lift capacitor and a voltage multiplier cell. A high voltage gain of the converter can be achieved with a reasonable duty ratio and the voltage stresses of semiconductor devices are reduced. Because of low voltage stress, the switches with low on-resistance and the diodes with low forward voltage drops can be adopted to minimize the conduction losses. Additionally, the switching losses are reduced because the switches are turned on under zero-current switching (ZCS) conditions. Due to the existence of leakage inductances of the coupled inductors, the diode reverse-recovery problem is alleviated. Moreover, the leakage energy is recycled and the voltage spikes during switch turn-off are avoided. The parallel input architecture and interleaved operation reduce the input current ripple. The operating principles, steady-state characteristics, and design considerations of the presented converter are proposed in detail. Furthermore, a closed-loop control is designed to maintain a well-regulated output voltage despite variations in input voltage and output load. A prototype converter with a rated 1000 W output power is realized for demonstration. Finally, experimental results show the converter effectiveness and verify the theoretical analysis. Full article
(This article belongs to the Special Issue Efficient and Resilient DC Energy Distribution Systems)
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24 pages, 1860 KiB  
Review
Exploiting the Molecular Properties of Fibrinogen to Control Bleeding Following Vascular Injury
by Tanjot Singh, Muhammad Hasan, Thembaninkosi G. Gaule and Ramzi A. Ajjan
Int. J. Mol. Sci. 2025, 26(3), 1336; https://doi.org/10.3390/ijms26031336 - 5 Feb 2025
Cited by 4 | Viewed by 2046
Abstract
The plasma protein fibrinogen is critical for haemostasis and wound healing, serving as the structural foundation of the blood clot. Through a complex interaction between coagulation factors, the soluble plasma fibrinogen is converted to insoluble fibrin networks, which form the skeleton of the [...] Read more.
The plasma protein fibrinogen is critical for haemostasis and wound healing, serving as the structural foundation of the blood clot. Through a complex interaction between coagulation factors, the soluble plasma fibrinogen is converted to insoluble fibrin networks, which form the skeleton of the blood clot, an essential step to limit blood loss after vascular trauma. This review examines the molecular mechanisms by which fibrinogen modulates bleeding, focusing on its interactions with other proteins that maintain fibrin network stability and prevent premature breakdown. Moreover, we also cover the role of fibrinogen in ensuring clot stability through the physiological interaction with platelets. We address the therapeutic applications of fibrinogen across various clinical contexts, including trauma-induced coagulopathy, postpartum haemorrhage, and cardiac surgery. Importantly, a full understanding of protein function will allow the development of new therapeutics to limit blood loss following vascular trauma, which remains a key cause of mortality worldwide. While current management strategies help with blood loss following vascular injury, they are far from perfect and future research should prioritise refining fibrinogen replacement strategies and developing novel agents to stabilise the fibrin network. Exploiting fibrinogen’s molecular properties holds significant potential for improving outcomes in trauma care, surgical interventions and obstetric haemorrhage. Full article
(This article belongs to the Special Issue New Advances in Thrombosis: 3rd Edition)
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24 pages, 4188 KiB  
Article
On the Biosynthesis of Bioactive Tryptamines in Black Cohosh (Actaea racemosa L.)
by Martin J. Spiering, James F. Parsons and Edward Eisenstein
Plants 2025, 14(2), 292; https://doi.org/10.3390/plants14020292 - 20 Jan 2025
Viewed by 1297
Abstract
Botanical dietary supplements are widely used, but issues of authenticity, consistency, safety, and efficacy that complicate their poorly understood mechanism of action have prompted questions and concerns in the popular and scientific literature. Black cohosh (Actaea racemosa L., syn. Cimicifuga racemosa, [...] Read more.
Botanical dietary supplements are widely used, but issues of authenticity, consistency, safety, and efficacy that complicate their poorly understood mechanism of action have prompted questions and concerns in the popular and scientific literature. Black cohosh (Actaea racemosa L., syn. Cimicifuga racemosa, Nutt., Ranunculaceae) is a multicomponent botanical therapeutic used as a popular remedy for menopause and dysmenorrhea and explored as a treatment in breast and prostate cancer. However, its use and safety are controversial. A. racemosa tissues contain the bioactive serotonin analog N-methylserotonin, which is thought to contribute to the serotonergic activities of black cohosh–containing preparations. A. racemosa has several TDC-like genes hypothesized to encode tryptophan decarboxylases (TDCs) converting L-tryptophan to tryptamine, a direct serotonin precursor in plants. Expression of black cohosh TDC1, TDC2, and TDC3 in Saccharomyces cerevisiae resulted in the production of tryptamine. TDC1 and TDC3 had approximately fourfold higher activity than TDC2, which was attributable to a variable Cys/Ser active site residue identified by site-directed mutagenesis. Co-expression in yeast of the high-activity black cohosh TDCs with the next enzyme in serotonin biosynthesis, tryptamine 5-hydroxylase (T5H), from rice (Oryza sativa) resulted in the production of serotonin, whereas co-expression with low-activity TDCs did not, suggesting that TDC activity is a rate-limiting step in serotonin biosynthesis. Two T5H-like sequences were identified in A. racemose, but their co-expression with the high-activity TDCs in yeast did not result in serotonin production. TDC expression was detected in several black cohosh tissues, and phytochemical analysis using LC-MS revealed several new tryptamines, including tryptamine and serotonin, along with N-methylserotonin and, interestingly, N-N-dimethyl-5-hydroxytryptamine (bufotenine), which may contribute to hepatotoxicity. Incubation of A. racemosa leaves with tryptamine and N-methyltryptamine resulted in increased concentrations of serotonin and N-methylserotonin, respectively, suggesting that methylation of tryptamine precedes hydroxylation in the biosynthesis of N-methylserotonin. This work indicates a significantly greater variety of serotonin derivatives in A. racemosa than previously reported. Moreover, the activities of the TDCs underscore their key role in the production of serotonergic compounds in A. racemosa. Finally, it is proposed that tryptamine is first methylated and then hydroxylated to form the black cohosh signature compound N-methylserotonin. Full article
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17 pages, 4096 KiB  
Article
Tending to the Facial Surfaces of a Mathematical Biology Head-Scratcher: Why Does the Head of the Sea Turtle Natator depressus Resemble a Convex Zygomorphic Dodecahedron?
by David A. Becker
Animals 2025, 15(1), 100; https://doi.org/10.3390/ani15010100 - 4 Jan 2025
Viewed by 1512
Abstract
Two convex polyhedra that markedly resemble the head of the flatback sea turtle hatchling are identified. The first example is a zygomorphic tetragonal dodecahedron, while the other, an even better matching structure, is a related tetradecahedron, herein speculated to arise from this particular [...] Read more.
Two convex polyhedra that markedly resemble the head of the flatback sea turtle hatchling are identified. The first example is a zygomorphic tetragonal dodecahedron, while the other, an even better matching structure, is a related tetradecahedron, herein speculated to arise from this particular dodecahedron via known mechanisms gleaned from studies of the behavior of foams. A segmented, biomorphic, convex polyhedral model to address cephalic topology is thus presented stemming from solid geometry, anatomical observations, and a recently computed densest local packing arrangement of fifteen slightly oblate spheroids in which fourteen oblate spheroids surround a central such spheroid. This particular array of oblate spheroids shares salient structural features with the aforementioned dodecahedron. Successful testing of the model has been achieved by converting this array of fifteen oblate spheroids constructed with putty to the cephaloid dodecahedron in a process involving ventral elongation induced by stretching in the anterior direction along the anteroposterior axis (convergent extension). During convergent extension, the two left most anterolateral oblate spheroids that are in direct contact with the ventral spheroid of the array merge into a single lateral facet of the incipient dodecahedron, while the corresponding two right such oblate spheroids do the same. Thus, the fourteen outer oblate spheroids of the array give rise to the twelve facets of the finalized dodecahedron, while the central oblate spheroid remnant assumes an interior dodecahedral position. The hypothetical dodecahedron to tetradecahedron transformation entails the collapse of a tetravalent vertex (which is known to occur in foams as part of a T1 transition) followed by bilateral facet splitting. Remarkably, a model stipulating that convexity is to be retained in connection with this sequence of steps necessitates that the starting dodecahedral template undergoes modification to become a tetradecahedron in possession of precisely the highly ordered feature found at the top of the head of numerous specimens of the flatback sea turtle hatchling, namely, a fused medial pentagon–heptagon pair in the form of a pentagonal frontal scute and heptagonal frontoparietal scute. Such a possible new instance of geometric biomorphy, taken together with the correct anticipation of the cephalic pentagon–heptagon pair, might serve to instill further confidence in renewed efforts to shed light on morphogenesis with foam embryo models. Full article
(This article belongs to the Special Issue Animal Geometric Morphometrics—Concepts, Methods, and Applications)
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