Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
 
 
Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (44,073)

Search Parameters:
Keywords = MMS

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
8 pages, 251 KiB  
Article
Does Monopolar Electrocautery Affect the Fetus during Cesarean Section?
by Sevki Goksun Gokulu, Hamza Yildiz, Ali Yildizbakan, Gorkem Ulger, Huseyin Durukan, Yalcin Celik and Hakan Aytan
Medicina 2024, 60(9), 1453; https://doi.org/10.3390/medicina60091453 (registering DOI) - 5 Sep 2024
Abstract
Background and Objectives: This study aimed to assess the impact of monopolar electrocautery on the fetus during cesarean section. Materials and methods: A retrospective analysis was conducted with 552 patients delivered by cesarean section. Patients were grouped based on usage of monopolar electrocautery. [...] Read more.
Background and Objectives: This study aimed to assess the impact of monopolar electrocautery on the fetus during cesarean section. Materials and methods: A retrospective analysis was conducted with 552 patients delivered by cesarean section. Patients were grouped based on usage of monopolar electrocautery. In 272 patients, monopolar electrocautery was used to separate the tissues before the delivery. In 280 patients, no electrocautery was used. Newborn vital signs, Apgar scores, umbilical cord blood parameters, newborn serum parameters collected within 6th postpartum hour, and rate of newborn intensive care unit admission were compared. Results: The 1st and 5th minute Apgar scores were significantly higher in the electrocautery group; however, this difference lost its significance at the 10th minute. The median newborn pulse rate (148 (7) vs. 146 (6) beats per minute, p = 0.026), umbilical cord blood pH, and partial oxygen pressure were significantly higher in the electrocautery group compared to the no-electrocautery group (7.34 ± 0.06 vs. 7.31 ± 0.06, p < 0.001, and 25.5 (14.77) vs. 23 (16.08) mmHg, p = 0.025, respectively). The median umbilical cord blood serum calcium level was 1.51 (0.64) mmol/L in the electrocautery group, which was significantly lower than 1.9 (0.82) mmol/L in the no-electrocautery group (p = 0.002). The incidence of hypoglycemia was significantly lower in the electrocautery group than in the no-electrocautery group (2.2% vs. 5.7%, p = 0.035). Conclusions: Monopolar electrocautery during cesarean section affects the fetus, but it is safe to use it. Electrocautery is independently associated with umbilical cord blood pH and calcium level. Electrocautery may be associated with a lower incidence of hypoglycemia. Full article
(This article belongs to the Section Obstetrics and Gynecology)
9 pages, 3799 KiB  
Communication
The Assessment of Methyl Methanesulfonate Absorption by Amphipods from the Environment Using Lux-Biosensors
by Uliana S. Novoyatlova, Anna A. Kudryavtseva, Sergey V. Bazhenov, Anna A. Utkina, Vadim V. Fomin, Shamil A. Nevmyanov, Bagila S. Zhoshibekova, Maria A. Fedyaeva, Mikhail Y. Kolobov and Ilya V. Manukhov
Biosensors 2024, 14(9), 427; https://doi.org/10.3390/bios14090427 (registering DOI) - 5 Sep 2024
Abstract
The ability of aquatic mesofauna representatives involved in trophic chains to sorb and accumulate toxicants is important for understanding the functioning of aquatic ecosystems and for fishing industry. This study investigated the capacity of marine amphipod Gammarus oceanicus and freshwater amphipods Eulimnogammarus vittatus [...] Read more.
The ability of aquatic mesofauna representatives involved in trophic chains to sorb and accumulate toxicants is important for understanding the functioning of aquatic ecosystems and for fishing industry. This study investigated the capacity of marine amphipod Gammarus oceanicus and freshwater amphipods Eulimnogammarus vittatus and Gammarus lacustris to absorb the DNA-alkylating agent methyl methanesulfonate (MMS). The presence of alkylating agents in the environment and in the tissues of the amphipods was determined using whole-cell lux-biosensor Escherichia coli MG1655 pAlkA-lux, in which the luxCDABE genes from Photorhabdus luminescens, enabling the luminescence of the cell culture, are controlled by the PalkA promoter of DNA glycosylase. It was shown that within one day of incubation in water containing MMS at a concentration above 10 μM, the amphipods absorbed the toxicant and their tissues produce more alkylation damage to biosensor cells than the surrounding water. Concentrations of MMS above 1 mM in the environment caused the death of the amphipods before the toxicant could be significantly concentrated in their tissues. The sensitivity and the capacity to absorb MMS were found to be approximately the same for the marine amphipod G. oceanicus and the freshwater amphipods E. vittatus and G. lacustris. Full article
(This article belongs to the Section Environmental Biosensors and Biosensing)
Show Figures

Figure 1

12 pages, 1694 KiB  
Article
Machine Learning Regressors to Estimate Continuous Oxygen Uptakes (V˙O2)
by Daeeon Hong and Sukkyu Sun
Appl. Sci. 2024, 14(17), 7888; https://doi.org/10.3390/app14177888 (registering DOI) - 5 Sep 2024
Abstract
Oxygen consumption (V˙O2) estimation is vital for evaluating aerobic performance and cardiovascular fitness. This study explores various regression models to develop a real-time V˙O2 and V˙O2max estimation model. Utilizing [...] Read more.
Oxygen consumption (V˙O2) estimation is vital for evaluating aerobic performance and cardiovascular fitness. This study explores various regression models to develop a real-time V˙O2 and V˙O2max estimation model. Utilizing a dataset from PhysioNet, encompassing cardiorespiratory measurements from 992 treadmill tests conducted at the University of Malaga’s Exercise Physiology and Human Performance Lab from 2008 to 2018, participants aged 10 to 63, including amateur and professional athletes, underwent breath-by-breath monitoring of physiological parameters. The study underlines the efficacy of regressor models in handling complex datasets and developing a robust real-time V˙O2 estimation model. After adjusting parameters to V˙O2 in “mL/kg/min” from “mL/min”, and selecting ‘Age’, ‘Weight’, ‘Height’, ‘HR’, ‘Sex’, and ‘Time’ as parameters for V˙O2 estimation, XGBoost emerged as the optimal choice. Validation using a test dataset of 132 participants yielded the following results for Mean Absolute Error (MAE), Mean Squared Error (MSE), Root Mean Squared Error (RMSE), R-squared (R2), Root Mean Squared Logarithmic Error (RMSLE), and Mean Absolute Percentage Error (MAPE) metrics: MAE of 0.1793, MSE of 0.1460, RMSE of 0.3821, R2 of 0.9991, RMSLE of 0.0140, and MAPE of 0.0066. This study demonstrates the effectiveness of various regressor models in developing a continuous V˙O2max estimation model that has promising performance metrics. Full article
Show Figures

Figure 1

16 pages, 5675 KiB  
Article
A Facile and Efficient Protocol for Phospholipid Enrichment in Synovial Joint Fluid: Monodisperse-Mesoporous SiO2 Microspheres as a New Metal Oxide Affinity Sorbent
by Serhat Aladağ, İlayda Demirdiş, Burcu Gökçal Kapucu, Emine Koç, Ozan Kaplan, Batuhan Erhan Aktaş, Mustafa Çelebier, Ali Tuncel and Feza Korkusuz
Separations 2024, 11(9), 262; https://doi.org/10.3390/separations11090262 (registering DOI) - 5 Sep 2024
Abstract
Phospholipids (PLs), essential components of cell membranes, play significant roles in maintaining the structural integrity and functionality of joint tissues. One of the main components of synovial joint fluid (SJF) is PLs. Structures such as PLs that are found in low amounts in [...] Read more.
Phospholipids (PLs), essential components of cell membranes, play significant roles in maintaining the structural integrity and functionality of joint tissues. One of the main components of synovial joint fluid (SJF) is PLs. Structures such as PLs that are found in low amounts in biological fluids may need to be selectively enriched to be analyzed. Monodisperse-mesoporous SiO2 microspheres were synthesized by a multi-step hydrolysis condensation method for the selective enrichment and separation of PLs in the SJF. The microspheres were characterized by SEM, XPS, XRD, and BET analyses. SiO2 microspheres had a 161.5 m2/g surface area, 1.1 cm3/g pore volume, and 6.7 nm pore diameter, which were efficient in the enrichment of PLs in the SJF. The extracted PLs with sorbents were analyzed using Q-TOF LC/MS in a gradient elution mode with a C18 column [2.1 × 100 mm, 2.5 μM, Xbridge Waters (Milford, MA, USA)]. An untargeted lipidomic approach was performed, and the phospholipid enrichment was successfully carried out using the proposed solid-phase extraction (SPE) protocol. Recovery of the SPE extraction of PLs using sorbents was compared to the classical liquid–liquid extraction (LLE) procedure for lipid extraction. The results showed that monodisperse-mesoporous SiO2 microspheres were eligible for selective enrichment of PLs in SJF samples. These microspheres can be used to identify PLs changes in articular joint cartilage (AJC) in physiological and pathological conditions including osteoarthritis (OA) research. Full article
Show Figures

Figure 1

11 pages, 797 KiB  
Article
Haemodynamic Forces: Emerging Markers of Ventricular Remodelling in Multiple Myeloma Cardiovascular Baseline Risk Assessment
by Anna Colomba, Anna Astarita, Giulia Mingrone, Lorenzo Airale, Cinzia Catarinella, Fabrizio Vallelonga, Dario Leone, Marco Cesareo, Arianna Paladino, Sara Bringhen, Francesca Gay, Gianni Pedrizzetti, Franco Veglio and Alberto Milan
Cancers 2024, 16(17), 3081; https://doi.org/10.3390/cancers16173081 - 4 Sep 2024
Abstract
Multiple myeloma (MM) affects a population with a high prevalence of cardiovascular (CV) disease. These patients benefit from an accurate CV risk evaluation in order to choose the safest drug regimen. Haemodynamic forces (HDFs) analysis allows for the earlier detection of myocardial damage [...] Read more.
Multiple myeloma (MM) affects a population with a high prevalence of cardiovascular (CV) disease. These patients benefit from an accurate CV risk evaluation in order to choose the safest drug regimen. Haemodynamic forces (HDFs) analysis allows for the earlier detection of myocardial damage compared with standard markers; the role played by MM in HDFs alteration, with or without the influence of hypertension, is yet to be studied. Therefore, we aimed to identify differences in HDFs analysis in patients with MM, hypertension or both versus normotensive non-oncologic subjects. A total of 173 patients (MM hypertensive patients, MMHT; MM normotensive patients, MMNT; non-oncologic hypertensive patients, CoHT; and non-oncologic normotensive patients, CoNT) underwent transthoracic echocardiography for HDFs analysis and pulse wave velocity (PWV) assessment. Hypertensive patients (MMHT, CoHT) showed decreased ejection fraction (EF), global longitudinal strain (GLS) and HDFs values compared with CoNT, whereas ventricular mass (LVMi) and PWV increased. MMNT displayed a significant reduction in systolic HDFs (p < 0.006) and systolic ejection HDFs (p < 0.008) compared with CoNT, without significant change in EF, GLS, LVMi or PWV. In conclusion, MM leads to ventricular remodelling regardless of hypertension; HDFs application for MM patients could help detect early myocardial damage, especially in patients receiving cardiotoxic drugs. Full article
(This article belongs to the Section Clinical Research of Cancer)
Show Figures

Figure 1

18 pages, 4222 KiB  
Article
Exploring Radioiodinated Anastrozole and Epirubicin as AKT1-Targeted Radiopharmaceuticals in Breast Cancer: In Silico Analysis and Potential Therapeutic Effect with Functional Nuclear Imagining Implications
by Mazen Abdulrahman Binmujlli
Molecules 2024, 29(17), 4203; https://doi.org/10.3390/molecules29174203 - 4 Sep 2024
Abstract
This study evaluates radio-iodinated anastrozole ([125I]anastrozole) and epirubicin ([125I]epirubicin) for AKT1-targeted breast cancer therapy, utilizing radiopharmaceutical therapy (RPT) for personalized treatment. Through molecular docking and dynamics simulations (200 ns), it investigates these compounds’ binding affinities and mechanisms to the [...] Read more.
This study evaluates radio-iodinated anastrozole ([125I]anastrozole) and epirubicin ([125I]epirubicin) for AKT1-targeted breast cancer therapy, utilizing radiopharmaceutical therapy (RPT) for personalized treatment. Through molecular docking and dynamics simulations (200 ns), it investigates these compounds’ binding affinities and mechanisms to the AKT1 enzyme, compared to the co-crystallized ligand, a known AKT1 inhibitor. Molecular docking results show that [125I]epirubicin has the highest ΔGbind (−11.84 kcal/mol), indicating a superior binding affinity compared to [125I] anastrozole (−10.68 kcal/mol) and the co-crystallized ligand (−9.53 kcal/mol). Molecular dynamics (MD) simulations confirmed a stable interaction with the AKT1 enzyme, with [125I]anastrozole and [125I]epirubicin reaching stability after approximately 68 ns with an average RMSD of around 2.2 Å, while the co-crystallized ligand stabilized at approximately 2.69 Å after 87 ns. RMSF analysis showed no significant shifts in residues or segments, with consistent patterns and differences of less than 2 Å, maintaining enzyme stability. The [125I]epirubicin complex maintained an average of four H-bonds, indicating strong and stable interactions, while [125I]anastrozole consistently formed three H-bonds. The average Rg values for both complexes were ~16.8 ± 0.1 Å, indicating no significant changes in the enzyme’s compactness, thus preserving structural integrity. These analyses reveal stable binding and minimal structural perturbations, suggesting the high potential for AKT1 inhibition. MM-PBSA calculations confirm the potential of these radio-iodinated compounds as AKT1 inhibitors, with [125I]epirubicin exhibiting the most favorable binding energy (−23.57 ± 0.14 kcal/mol) compared to [125I]anastrozole (−20.03 ± 0.15 kcal/mol) and the co-crystallized ligand (−16.38 ± 0.14 kcal/mol), highlighting the significant role of electrostatic interactions in stabilizing the complex. The computational analysis shows [125I]anastrozole and [125I]epirubicin may play promising roles as AKT1 inhibitors, especially [125I]epirubicin for its high binding affinity and dynamic receptor interactions. These findings, supported by molecular docking scores and MM-PBSA binding energies, advocate for their potential superior inhibitory capability against the AKT1 enzyme. Nevertheless, it is crucial to validate these computational predictions through in vitro and in vivo studies to thoroughly evaluate the therapeutic potential and viability of these compounds for AKT1-targeted breast cancer treatment. Full article
Show Figures

Figure 1

24 pages, 3471 KiB  
Article
Novel Pyrrole Derivatives as Multi-Target Agents for the Treatment of Alzheimer’s Disease: Microwave-Assisted Synthesis, In Silico Studies and Biological Evaluation
by Emilio Mateev, Valentin Karatchobanov, Marjano Dedja, Konstantinos Diamantakos, Alexandrina Mateeva, Muhammed Tilahun Muhammed, Ali Irfan, Magdalena Kondeva-Burdina, Iva Valkova, Maya Georgieva and Alexander Zlatkov
Pharmaceuticals 2024, 17(9), 1171; https://doi.org/10.3390/ph17091171 - 4 Sep 2024
Abstract
Considering the complex pathogenesis of Alzheimer’s disease (AD), the multi-target ligand strategy is expected to provide superior effects for the treatment of the neurological disease compared to the classic single target strategy. Thus, one novel pyrrole-based hydrazide (vh0) and four corresponding [...] Read more.
Considering the complex pathogenesis of Alzheimer’s disease (AD), the multi-target ligand strategy is expected to provide superior effects for the treatment of the neurological disease compared to the classic single target strategy. Thus, one novel pyrrole-based hydrazide (vh0) and four corresponding hydrazide–hydrazones (vh1-4) were synthesized by applying highly efficient MW-assisted synthetic protocols. The synthetic pathway provided excellent yields and reduced reaction times under microwave conditions compared to conventional heating. The biological assays indicated that most of the novel pyrroles are selective MAO-B inhibitors with IC50 in the nanomolar range (665 nM) and moderate AChE inhibitors. The best dual-acting MAO-B/AChE inhibitor (IC50 hMAOB–0.665 μM; IC50 eeAChE—4.145 μM) was the unsubstituted pyrrole-based hydrazide (vh0). Importantly, none of the novel molecules displayed hMAOA-blocking capacities. The radical-scavenging properties of the compounds were examined using DPPH and ABTS in vitro tests. Notably, the hydrazide vh0 demonstrated the best antioxidant activities. In addition, in silico simulations using molecular docking and MM/GBSA, targeting the AChE (PDB ID: 4EY6) and MAO-B (PDB: 2V5Z), were utilized to obtain active conformations and to optimize the most prominent dual inhibitor (vh0). The ADME and in vitro PAMPA studies demonstrated that vh0 could cross the blood–brain barrier, and it poses good lead-like properties. Moreover, the optimized molecular structures and the frontier molecular orbitals were examined via DFT studies at 6-311G basis set in the ground state. Full article
(This article belongs to the Special Issue Pharmacotherapy of Neurodegeneration Disorders)
Show Figures

Figure 1

21 pages, 6806 KiB  
Article
Periodic Arrays of Plasmonic Ag-Coated Multiscale 3D-Structures with SERS Activity: Fabrication, Modelling and Characterisation
by Marta Lafuente, Lucas J. Kooijman, Sergio G. Rodrigo, Erwin Berenschot, Reyes Mallada, María P. Pina, Niels R. Tas and Roald M. Tiggelaar
Micromachines 2024, 15(9), 1129; https://doi.org/10.3390/mi15091129 - 4 Sep 2024
Abstract
Surface enhanced Raman spectroscopy (SERS) is gaining importance as sensing tool. However, wide application of the SERS technique suffers mainly from limitations in terms of uniformity of the plasmonics structures and sensitivity for low concentrations of target analytes. In this work, we present [...] Read more.
Surface enhanced Raman spectroscopy (SERS) is gaining importance as sensing tool. However, wide application of the SERS technique suffers mainly from limitations in terms of uniformity of the plasmonics structures and sensitivity for low concentrations of target analytes. In this work, we present SERS specimens based on periodic arrays of 3D-structures coated with silver, fabricated by silicon top-down micro and nanofabrication (10 mm × 10 mm footprint). Each 3D-structure is essentially an octahedron on top of a pyramid. The width of the top part—the octahedron—was varied from 0.7 µm to 5 µm. The smallest structures reached an analytical enhancement factor (AEF) of 3.9 × 107 with a relative standard deviation (RSD) below 20%. According to finite-difference time-domain (FDTD) simulations, the origin of this signal amplification lies in the strong localization of electromagnetic fields at the edges and surfaces of the octahedrons. Finally, the sensitivity of these SERS specimens was evaluated under close-to-reality conditions using a portable Raman spectrophotometer and monitoring of the three vibrational bands of 4-nitrobenzenethiol (4-NBT). Thus, this contribution deals with fabrication, characterization and simulation of multiscale 3D-structures with SERS activity. Full article
(This article belongs to the Special Issue The 15th Anniversary of Micromachines)
Show Figures

Figure 1

17 pages, 6627 KiB  
Article
An Optimization Study of 3D Printing Technology Utilizing a Hybrid Gel System Based on Astragalus Polysaccharide and Wheat Starch
by Guofeng Xia, Lilulu Tao, Shiying Zhang, Xiangyang Hao and Shengyang Ou
Processes 2024, 12(9), 1898; https://doi.org/10.3390/pr12091898 - 4 Sep 2024
Abstract
This study utilizes a lab-developed pneumatic-extrusion condensing 3D food printer to prepare astragalus–starch mixed gels by blending different ratios of astragalus polysaccharide and wheat starch and applies these gels to 3D printing experiments. The aim of this paper is to investigate the impacts [...] Read more.
This study utilizes a lab-developed pneumatic-extrusion condensing 3D food printer to prepare astragalus–starch mixed gels by blending different ratios of astragalus polysaccharide and wheat starch and applies these gels to 3D printing experiments. The aim of this paper is to investigate the impacts of mixed-gel concentrations on printing outcomes in order to identify the optimal blending ratio. Under this rationale, the effects of printing layer height and nozzle diameter on print quality were studied. Single-factor analysis and response surface methodology were employed to optimize the experiments and determine the optimal printing process parameters for the astragalus–starch mixed gels. The results indicate that an increase in astragalus polysaccharide content leads to a decrease in the sedimentation rate of the mixed gels and a tendency towards a more fluid consistency. After storage of samples in a sealed space for equal durations, it was found that an increase in astragalus polysaccharide content enhances the textural properties of the mixed gels, with optimal printing effects achieved at a 2% polysaccharide content. The optimal print quality is achieved when the ratio of nozzle diameter to layer height is between 0.5 and 0.55. The influence order of printing process parameters on the overall completion rate of the samples is nozzle diameter > printing speed > fill rate. The predicted optimal printing parameters are a nozzle diameter of 0.6 mm, a printing speed of 767 mm/min, and a fill rate of 83%, with a predicted overall completion rate of the printed samples at 99.45%. Experimental validation revealed an actual overall completion rate of the printed samples at 99.52%, slightly higher than the predicted value. This discrepancy was attributed to the precision of the measurement methods and the variability in the printing process. The study demonstrates that the addition of astragalus polysaccharide significantly improves the 3D printing molding effect of wheat starch, and the printing parameter settings obtained by response surface optimization effectively enhance printing accuracy. This research provides experimental evidence and parameter optimization references for the application of non-starch polysaccharides in starch-based 3D food printing. Full article
(This article belongs to the Special Issue Research and Optimization of Food Processing Technology)
Show Figures

Figure 1

16 pages, 2779 KiB  
Article
Roles of Polymer Concentration and Ionic Strength in the Deposition of Chitosan of Fungal Origin onto Negatively Charged Surfaces
by María Ormeño-Martínez, Eduardo Guzmán, Laura Fernández-Peña, Andrew J. Greaves, Lionel Bureau, Francisco Ortega, Ramón G. Rubio and Gustavo S. Luengo
Biomimetics 2024, 9(9), 534; https://doi.org/10.3390/biomimetics9090534 - 4 Sep 2024
Abstract
This study examines the potential of fungal chitosan derived from Aspergillus niger as a sustainable alternative to traditional petrochemical-based ingredients in cosmetic products. Specifically, the research examines the solubility of fungal chitosan in aqueous solutions of varying ionic strength and its adsorption onto [...] Read more.
This study examines the potential of fungal chitosan derived from Aspergillus niger as a sustainable alternative to traditional petrochemical-based ingredients in cosmetic products. Specifically, the research examines the solubility of fungal chitosan in aqueous solutions of varying ionic strength and its adsorption onto negatively charged surfaces that mimic human hair keratin. The adsorption behavior, water content, and frictional properties of chitosan films were evaluated using a quartz crystal microbalance with dissipation monitoring and a surface force apparatus (SFA). The findings indicated that fungal chitosan exhibits good solubility at a pH of 4.5. Conversely, the adsorption of chitosan is subject to the influence of both polymer concentration and ionic strength. At the lowest ionic strengths, a screening-enhanced adsorption process occurs as a consequence of the reduction in chitosan solubility in the presence of salt. This results in the depletion of polymer chains from the solution and their subsequent deposition. An increase in ionic strength above 15–20 mM results in a worsening of the chitosan–surface interaction, due to the simultaneous screening of both the chitosan and the surface charges. This results in a hindrance to the adsorption process. The deposited films are highly hydrated, and this hydration increases with both polymer concentration and ionic strength. Furthermore, the films exhibit a predominantly elastic behavior, and the response of the films under shear deformations shows a strong dependence on the polymer concentration. These findings contribute to the development of environmentally friendly cosmetic formulations that meet consumer demands for sustainability. Full article
(This article belongs to the Special Issue Advances in Biomaterials, Biocomposites and Biopolymers 2024)
Show Figures

Figure 1

12 pages, 4615 KiB  
Article
A Study on Miniaturized In-Situ Self-Calibrated Thermometers Based on Ga and Ga-Zn Fixed Points
by Haiying Huang, Wenlu Cai, Yongjian Mao, Kun Wan, Yong Wen, Yuqiang Han, Qiang Zhang, Rong Zhang and Xing Zheng
Sensors 2024, 24(17), 5744; https://doi.org/10.3390/s24175744 - 4 Sep 2024
Abstract
In order to ensure the reliability and accuracy of long-term temperature measurement where the thermometers are discommodious or even impossible to access for conventional periodical calibration, a study on miniaturized in-situ self-calibrated (MISSC) thermometers based on Ga and Ga-Zn fixed points was conducted [...] Read more.
In order to ensure the reliability and accuracy of long-term temperature measurement where the thermometers are discommodious or even impossible to access for conventional periodical calibration, a study on miniaturized in-situ self-calibrated (MISSC) thermometers based on Ga and Ga-Zn fixed points was conducted using temperature scale transfer technology. One MISSC thermometer consists of three parts: the first is the fixed-points hardware, including a container with two cells separately filled with Ga and Ga-Zn; the second is the temperature sensing hardware, made of a Type T thermocouple; the third is the mini-power heating hardware, made of a film resistance. The measurement and calibration (M&C) system comprises a temperature measurement and data processing subsystem and a mini-power heating control subsystem. Then, an in-situ self-calibration can be carried out by mini-power heating from a room temperature of about 20 °C, and then by comparison between the measured phase transition plateau results and the standard fixed-points, i.e., Ga fixed point (about 29.76 °C) and Ga-Zn fixed point (about 25.20 °C). A series of experiments were performed, and the results show that: (1) both the proposed hardware design and the self-calibration method are feasible, and (2) the Φ16 mm × 25 mm MISSC thermometer is found to be the most miniaturized one that can realize reliable self-calibration in this study. Full article
(This article belongs to the Section Physical Sensors)
Show Figures

Figure 1

27 pages, 24204 KiB  
Article
Modeling, Simulation and Control of the Double Delta Surgical Robot
by George Moustris and Costas Tzafestas
Machines 2024, 12(9), 620; https://doi.org/10.3390/machines12090620 - 4 Sep 2024
Abstract
Robotic surgery has been steadily growing, with many new platforms entering the field. Research platforms, however, are limited in number, require a sizable capital expenditure or are difficult to access. This paper presents the analysis and development of a novel surgical manipulator based [...] Read more.
Robotic surgery has been steadily growing, with many new platforms entering the field. Research platforms, however, are limited in number, require a sizable capital expenditure or are difficult to access. This paper presents the analysis and development of a novel surgical manipulator based on parallel kinematics, utilizing the Delta robot as a foundational element. We investigate various aspects including kinematics, statics, workspace and constraints of the manipulator. Additionally, a physics-based model is constructed to validate the analysis and facilitate the creation of a control algorithm aimed at input tracking, particularly for teleoperation purposes. Two experiments are conducted to evaluate the manipulator’s performance: one focusing on circle tracking and a second one employing real kinematic data from a suturing task. The results indicate a maximum tracking error under 1 mm and an RMS error below 0.6 mm for the first trial and 0.3 mm by 2 mm for the suturing tracking task, respectively. Furthermore, through non-linear Bode analysis we demonstrate that the closed-loop system effectively decouples input–output cross-gain terms while maintaining minimal amplification in the diagonal terms. This suggests that the system is well-suited for the intricate and precise motions required in surgical procedures. Full article
(This article belongs to the Section Robotics, Mechatronics and Intelligent Machines)
Show Figures

Figure 1

18 pages, 2801 KiB  
Article
Integrated Drip Irrigation Regulates Soil Water–Salt Movement to Improve Water Use Efficiency and Maize Yield in Saline–Alkali Soil
by Mengze Wang, Rui Wang, Quan Sun, Yulong Li, Lizhen Xu and Yaqi Wang
Water 2024, 16(17), 2509; https://doi.org/10.3390/w16172509 - 4 Sep 2024
Abstract
Soil salinization is a critical issue impacting agriculture, particularly in arid and semi-arid regions. The objective of this study was to evaluate the effects of different drip irrigation and fertilization treatments on soil water and salt dynamics, maize water use efficiency, and crop [...] Read more.
Soil salinization is a critical issue impacting agriculture, particularly in arid and semi-arid regions. The objective of this study was to evaluate the effects of different drip irrigation and fertilization treatments on soil water and salt dynamics, maize water use efficiency, and crop yield in the saline–alkali soils of northern Ningxia, China. Over three years, four irrigation treatments were tested: CK (flood irrigation, 810 mm), W1 (low-volume drip irrigation, 360 mm), W2 (medium-volume drip irrigation, 450 mm), and W3 (high-volume drip irrigation, 540 mm). The results demonstrate that treatments W2 and W3 significantly increased soil moisture content at depths of 0–20 cm and 60–100 cm compared to CK, facilitating uniform salt leaching in the 0–40 cm soil layer. However, in the 40–100 cm layer, decreased porosity and upward moisture movement hindered salt migration, resulting in subsurface salt accumulation. Furthermore, drip irrigation combined with fertilization significantly reduced phosphorus fixation and nitrogen leaching, enhancing nutrient availability. This led to a reduction in underground leakage and surface evaporation by up to 39.63%, while water use efficiency improved by 18.97% to 55.13%. By the third year, grain yields under drip irrigation treatments increased significantly compared to CK, with W3 showing the highest gains (up to 21.90%). This study highlights the potential of integrating drip irrigation and fertilization as an effective strategy for managing saline–alkali soils, improving water use, and increasing crop productivity, providing valuable insights for sustainable agricultural practices. Full article
(This article belongs to the Special Issue Sustainable Irrigation Systems Management for Agriculture)
Show Figures

Figure 1

20 pages, 16114 KiB  
Article
Investigation on the Solidification Structure of Q355 in 475 mm Extra-Thick Slabs Adopting Cellular Automaton-Finite Element Model
by Kezai Yu, Minglin Wang, Haihan Fan, Zhonghua Zhan, Zixiang Ren and Lijun Xu
Metals 2024, 14(9), 1012; https://doi.org/10.3390/met14091012 - 4 Sep 2024
Abstract
The solidification structure characteristics are decisive for the production of extra-thick slabs. This study developed a solidification heat transfer model and a cellular automaton–finite element coupled model to investigate the solidification behavior and structure characteristics of a 475 mm extra-thick slab. The models [...] Read more.
The solidification structure characteristics are decisive for the production of extra-thick slabs. This study developed a solidification heat transfer model and a cellular automaton–finite element coupled model to investigate the solidification behavior and structure characteristics of a 475 mm extra-thick slab. The models were applied under various continuous casting process parameters and different alloy element content. The simulation results reveal that casting speed has the most significant effect on the solidification behavior of extra-thick slabs, surpassing the impact of specific water flow and superheat. The solidification structure characteristics of the 475 mm extra-thick slabs were investigated under various conditions. The findings indicate that at higher casting speeds and superheats, the average grain size increases and the grain number decreases. The average grain size initially decreases and then increases with the rise in specific water flow, reaching its minimum at approximately 0.17 L·kg−1. Additionally, the average grain radius first decreases and then slightly increases with an increase in carbon content, achieving the minimum value of about 0.17% carbon. Compared with carbon and manganese, silicon has a greater impact on the solidification structure of ultra-thick slabs, and a moderate increase in silicon content can effectively refine the grain size. This study provides a theoretical foundation for understanding the changes in solidification structure characteristics and optimizing continuous casting process parameters for 475 mm extra-thick slabs. Full article
(This article belongs to the Special Issue Green Super-Clean Steels)
Show Figures

Figure 1

19 pages, 5746 KiB  
Article
Dual-Wavelength LiDAR with a Single-Pixel Detector Based on the Time-Stretched Method
by Simin Chen, Shaojing Song, Yicheng Wang, Hao Pan, Fashuai Li and Yuwei Chen
Sensors 2024, 24(17), 5741; https://doi.org/10.3390/s24175741 - 4 Sep 2024
Abstract
In the fields of agriculture and forestry, the Normalized Difference Vegetation Index (NDVI) is a critical indicator for assessing the physiological state of plants. Traditional imaging sensors can only collect two-dimensional vegetation distribution data, while dual-wavelength LiDAR technology offers the capability to capture [...] Read more.
In the fields of agriculture and forestry, the Normalized Difference Vegetation Index (NDVI) is a critical indicator for assessing the physiological state of plants. Traditional imaging sensors can only collect two-dimensional vegetation distribution data, while dual-wavelength LiDAR technology offers the capability to capture vertical distribution information, which is essential for forest structure recovery and precision agriculture management. However, existing LiDAR systems face challenges in detecting echoes at two wavelengths, typically relying on multiple detectors or array sensors, leading to high costs, bulky systems, and slow detection rates. This study introduces a time-stretched method to separate two laser wavelengths in the time dimension, enabling a more cost-effective and efficient dual-spectral (600 nm and 800 nm) LiDAR system. Utilizing a supercontinuum laser and a single-pixel detector, the system incorporates specifically designed time-stretched transmission optics, enhancing the efficiency of NDVI data collection. We validated the ranging performance of the system, achieving an accuracy of approximately 3 mm by collecting data with a high sampling rate oscilloscope. Furthermore, by detecting branches, soil, and leaves in various health conditions, we evaluated the system’s performance. The dual-wavelength LiDAR can detect variations in NDVI due to differences in chlorophyll concentration and water content. Additionally, we used the radar equation to analyze the actual scene, clarifying the impact of the incidence angle on reflectance and NDVI. Scanning the Red Sumach, we obtained its NDVI distribution, demonstrating its physical characteristics. In conclusion, the proposed dual-wavelength LiDAR based on the time-stretched method has proven effective in agricultural and forestry applications, offering a new technological approach for future precision agriculture and forest management. Full article
(This article belongs to the Section Radar Sensors)
Show Figures

Figure 1

Back to TopTop