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16 pages, 912 KiB

Open AccessArticle

Biomechanical Behavior of Injected Cement Spacers versus Traditional Cages in Low-Density Lumbar Spine under Compression Loading

by Tibor Csakany, Peter Varga, Boyko Gueorguiev, Eva Lakatos and Marta Kurutz

Medicina 2024, 60(7), 1155; https://doi.org/10.3390/medicina60071155 (registering DOI) - 17 Jul 2024

Abstract

Background and Objectives: Osteoporosis renders the use of traditional interbody cages potentially dangerous given the high risk of damage in the bone–implant interface. Instead, injected cement spacers can be applied as interbody devices; however, this technique has been mainly used in cervical [...] Read more.

Background and Objectives: Osteoporosis renders the use of traditional interbody cages potentially dangerous given the high risk of damage in the bone–implant interface. Instead, injected cement spacers can be applied as interbody devices; however, this technique has been mainly used in cervical spine surgery. This study aimed at investigating the biomechanical behavior of cement spacers versus traditional cages in lumbar spine surgery. Materials and Methods: Destructive monotonic axial compression testing was performed on 20 human cadaveric low-density lumbar segments from elderly donors (14 f/6 m, 70.3 ± 12.0 y) treated with either injected cement spacers (n = 10) or traditional cages (n = 10) without posterior instrumentation. Stiffness, failure load and displacement were compared. The effects of bone density, vertebral geometry and spacer contact area were evaluated. Results: Cement spacers demonstrated higher stiffness, significantly smaller displacement (p < 0.001) and a similar failure load compared to traditional cages. In the cage group, stiffness and failure load depended strongly on bone density and vertebral height, whereas failure displacement depended on vertebral anterior height. No such correlations were identified with cement spacers. Conclusions: Cement spacers used in lumbar interbody stabilization provided similar compression strength, significantly smaller failure displacement and a stiffer construct than traditional cages that provided benefits mainly for large and strong vertebrae. Cement stabilization was less sensitive to density and could be more beneficial also for segments with smaller and less dense vertebrae. In contrast to the injection of cement spacers, the optimal insertion of cages into the irregular intervertebral space is challenging and risks damaging bone. Further studies are required to corroborate these findings and the treatment selection thresholds. Full article

(This article belongs to the Section Orthopedics)

16 pages, 1065 KiB

Open AccessSystematic Review

Anti-TNF Alpha and Risk of Lymphoma in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

by Ahmad A. Imam

Medicina 2024, 60(7), 1156; https://doi.org/10.3390/medicina60071156 (registering DOI) - 17 Jul 2024

Abstract

Background and Objectives: Anti-tumor necrosis factor-alpha (TNF-α) agents are effective in treating rheumatoid arthritis (RA) but may entail a risk of lymphoma due to TNF-α’s role in immune surveillance. This systematic review and meta-analysis assesses the risk of lymphoma in patients with [...] Read more.

Background and Objectives: Anti-tumor necrosis factor-alpha (TNF-α) agents are effective in treating rheumatoid arthritis (RA) but may entail a risk of lymphoma due to TNF-α’s role in immune surveillance. This systematic review and meta-analysis assesses the risk of lymphoma in patients with RA treated with anti-TNF agents versus patients treated with methotrexate and/or a placebo. Materials and Methods: The Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Embase, PubMed, and Google Scholar were systematically searched for relevant literature. Data were extracted and analyzed to determine risk ratios (RRs) and 95% confidence intervals (CIs), with heterogeneity assessed using I² statistics. Methodological quality and risk of bias were assessed using the Cochrane Risk of Bias tool for randomized controlled trials (RCTs) and the Newcastle–Ottawa Scale for observational studies. Results: The search yielded 932 articles, 13 of which were retained for qualitative review and 12 for quantitative synthesis. Overall, the studies reviewed included 181,735 participants: 3772 from six RCTs and 177,963 from seven observational studies. The meta-analysis of RCTs revealed no significant difference in the risk of lymphoma between patients receiving anti-TNF-α therapy and patients on conventional treatments, with an overall RR of 1.43 (95% CI: 0.32–5.16) and I² of 0%. Conversely, observational studies showed some variability, with an overall RR of 1.43 (95% CI: 0.59–3.47) and significant heterogeneity (I² = 95%), whereas others indicated a potentially elevated risk of lymphoma in specific subgroups but had inconsistent results. Conclusions: The systematic and meta-analysis revealed no significant difference in the risk of lymphoma for patients with RA treated with anti-TNF-α agents versus conventional therapies. However, given the limitations of the studies included, additional research is needed to validate the results and explore potential risk factors contributing to the development of lymphoma in patients with RA. Full article

(This article belongs to the Section Oncology)

20 pages, 1075 KiB

Open AccessArticle

The Influence of Brand Greenwashing on EV Purchase Intention: The Moderating Role of Consumer Innovativeness and Peer Brand Attitude

by Yuting Liao and Liang Wu

World Electr. Veh. J. 2024, 15(7), 313; https://doi.org/10.3390/wevj15070313 (registering DOI) - 17 Jul 2024

Abstract

In the context of new energy Electric Vehicles (EVs), certain car manufacturers engage in deceptive behaviors known as “greenwashing”, including activities such as “subsidy cheating”, “exaggerating carbon reduction claims”, and “selective disclosure of environmental information”. These behaviors have a negative impact on industry [...] Read more.

In the context of new energy Electric Vehicles (EVs), certain car manufacturers engage in deceptive behaviors known as “greenwashing”, including activities such as “subsidy cheating”, “exaggerating carbon reduction claims”, and “selective disclosure of environmental information”. These behaviors have a negative impact on industry progress. While previous studies suggest that consumers’ perceptions of greenwashing towards individual brands extend to the industry as a whole and influence their overall purchase intentions, there remains a gap in understanding how these behaviors specifically affect consumers’ willingness to purchase EVs. To address this gap and enrich the literature on the relationship between greenwashing and consumer choice, this study uses ABC attitude theory and experimental methods to investigate the impact of greenwashing in the EV sector on consumers’ vehicle preferences in three experiments. The results show that consumers’ perceptions of greenwashing in one EV brand negatively influence their purchase intentions towards other brands, mediated by a general skepticism towards environmental claims in the industry. In addition, consumers’ innovativeness and attitudes towards other brands play a negative moderating role in this relationship. The research findings provide comprehensive insights into the complex impact of brand greenwashing on consumer behavior within the EV industry. Full article

(This article belongs to the Special Issue The Contribution of Electric Vehicles to Realization of Dual Carbon Goal)

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12 pages, 633 KiB

Open AccessArticle

The Impact of Orthodontic Extrusion on Keratinized Gingiva

by Ivan Arsić, Nemanja Marinković, Tina Pajević, Jovan Marković, Miroslav Dragović, Zorana Stamenković, Neda Stefanović and Nenad Nedeljković

Medicina 2024, 60(7), 1157; https://doi.org/10.3390/medicina60071157 (registering DOI) - 17 Jul 2024

Abstract

Background and Objectives: The key factor that enables osteoblastic activity and the formation of new bone, as well as gingiva, during orthodontic tooth extrusion (OE) is the periodontal ligament. The reaction of periodontal tissues associated with changes in the gingiva is a [...] Read more.

Background and Objectives: The key factor that enables osteoblastic activity and the formation of new bone, as well as gingiva, during orthodontic tooth extrusion (OE) is the periodontal ligament. The reaction of periodontal tissues associated with changes in the gingiva is a part of orthodontic tooth displacement. The aim of this study was to examine the effect of OE on the width of the zone of the keratinized and attached gingiva, the position of the mucogingival junction, and the height of the interdental papillae in the region where the OE was performed as well as in the adjacent region. Materials and Methods: This research included 28 adult patients (both orthodontically treated and untreated). The treated group included 15 patients, in whom orthodontic extrusion of the upper or lower frontal teeth was indicated and performed. The untreated group included 13 patients, with no previous or undergoing orthodontic treatment. Patients with periodontal disease and periodontal pockets in the frontal region and patients allergic to iodine were excluded from the study. Gingivomorphometric measurements were performed on two occasions in three groups of teeth (24 extruded and 30 agonist teeth in the treated patients; 66 teeth in the untreated patients). Statistical analysis of the obtained data was performed using the software package SPSS version 26.0. Results: Orthodontic extrusion induced changes in the position of the mucogingival line and an increase in the width of the keratinized gingiva. There were no statistically significant effects on the depth of the gingival sulcus, the attached gingiva width, or the height of the interdental papillae. Conclusions: Orthodontic tooth extrusion has an effect on the periodontium in the observed region. Vertical orthodontic force, directed towards the coronal plane, affects the surrounding soft oral tissues. Full article

(This article belongs to the Special Issue Advances in Clinical Periodontology)

21 pages, 1074 KiB

Open AccessArticle

Probabilistic Path Planning for UAVs in Forest Fire Monitoring: Enhancing Patrol Efficiency through Risk Assessment

by Yuqin Wang, Fengsen Gao and Minghui Li

Fire 2024, 7(7), 254; https://doi.org/10.3390/fire7070254 (registering DOI) - 17 Jul 2024

Abstract

Forest fire is a significant global natural disaster, and unmanned aerial vehicles (UAVs) have gained attention in wildfire prevention for their efficient and flexible monitoring capabilities. Proper UAV patrol path planning can enhance fire-monitoring accuracy and response speed. This paper proposes a probabilistic [...] Read more.

Forest fire is a significant global natural disaster, and unmanned aerial vehicles (UAVs) have gained attention in wildfire prevention for their efficient and flexible monitoring capabilities. Proper UAV patrol path planning can enhance fire-monitoring accuracy and response speed. This paper proposes a probabilistic path planning (PPP) module that plans UAV patrol paths by combining real-time fire occurrence probabilities at different points. Initially, a forest fire risk logistic regression model is established to compute the fire probabilities at different patrol points. Subsequently, a patrol point filter is applied to remove points with low fire probabilities. Finally, combining fire probabilities with distances between patrol points, a dynamic programming (DP) algorithm is employed to generate an optimal UAV patrol route. Compared with conventional approaches, the experimental results demonstrate that the PPP module effectively improves the timeliness of fire monitoring and containment, and the introduction of DP, considering that the fire probabilities and the patrol point filter both contribute positively to the experimental outcomes. Different combinations of patrol point coordinates and their fire probabilities are further studied to summarize the applicability of this method, contributing to UAV applications in forest fire monitoring and prevention. Full article

(This article belongs to the Special Issue Drone Applications Supporting Fire Management)

28 pages, 7587 KiB

Open AccessArticle

Control and Application of Tree Obstacle-Clearing Coaxial Octocopter with Flexible Suspension Saw

by Luwei Liao, Zhong Yang, Haoze Zhuo, Nuo Xu, Wei Wang, Kun Tao, Jiabing Liang and Qiuyan Zhang

Drones 2024, 8(7), 328; https://doi.org/10.3390/drones8070328 (registering DOI) - 17 Jul 2024

Abstract

Aiming at the challenges of clearing tree obstacles along power transmission lines, the control and application of a novel Tree-Obstacle Clearing Coaxial Octocopter with Flexible Suspension Saw (TOCCO-FSS) have been investigated. Firstly, an overall scheme design and modeling of the TOCCO-FSS were conducted, [...] Read more.

Aiming at the challenges of clearing tree obstacles along power transmission lines, the control and application of a novel Tree-Obstacle Clearing Coaxial Octocopter with Flexible Suspension Saw (TOCCO-FSS) have been investigated. Firstly, an overall scheme design and modeling of the TOCCO-FSS were conducted, and dynamic modeling of the TOCCO-FSS was performed using the Lagrange equation. Secondly, to address the interference encountered during the operation, a contact operation model was established to estimate the uncertainties and external disturbances during the contact operation process. Further, the Non-Singular Terminal Sliding-Mode Active Disturbance Rejection Control (NTSM-ADRC) method was researched based on the mathematical model of the TOCCO-FSS. Finally, the performance of the controller was verified through simulations and physical experiments. The results demonstrate that the design, control, and application of the entire TOCCO-FSS system are effective. Full article

11 pages, 8638 KiB

Open AccessArticle

Thermal, Mechanical and Electrical Properties of Ag Nanoparticle–Polymethyl Methacrylate Composites Under Different Service Temperatures

by Xin-Gang Chen and Yang-Fei Zhang

J. Compos. Sci. 2024, 8(7), 279; https://doi.org/10.3390/jcs8070279 (registering DOI) - 17 Jul 2024

Abstract

Ag-nanoparticle-reinforced polymethyl methacrylate (AgNP/PMMA) composites are widely used in healthcare, electronics, construction, transportation and many other fields. As the service temperature fluctuates easily, it is necessary to study the temperature effect on the properties of AgNP/PMMA composites. In this work, a preparation method [...] Read more.

Ag-nanoparticle-reinforced polymethyl methacrylate (AgNP/PMMA) composites are widely used in healthcare, electronics, construction, transportation and many other fields. As the service temperature fluctuates easily, it is necessary to study the temperature effect on the properties of AgNP/PMMA composites. In this work, a preparation method of mixing and hot-pressing was used to fabricate multifunctional AgNP/PMMA composites that are suitable for large-scale industrial production. AgNPs are found to disperse homogeneously in the PMMA matrix. The thermal conductivity of the composite with 15 vol% AgNPs is 116.19% higher than that of PMMA and decreases as the temperature rises. Flexural strength increases first and then decreases with the rising of AgNP content and service temperature, while the flexural modulus decreases gradually. The minimum electrical resistivity of the composite achieves 1.37 × 10⁻³ Ω·m, with a low percolation threshold of 5 vol%, an improvement of nine orders of magnitude over PMMA. The results demonstrate that the service temperature has a significant effect on the comprehensive properties of AgNP/PMMA composites. Full article

(This article belongs to the Special Issue Characterization of Polymer Nanocomposites)

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17 pages, 836 KiB

Open AccessArticle

Bio-Inspired Optimization Algorithm Associated with Reinforcement Learning for Multi-Objective Operating Planning in Radioactive Environment

by Shihan Kong, Fang Wu, Hao Liu, Wei Zhang, Jinan Sun, Jian Wang and Junzhi Yu

Biomimetics 2024, 9(7), 438; https://doi.org/10.3390/biomimetics9070438 (registering DOI) - 17 Jul 2024

Abstract

This paper aims to solve the multi-objective operating planning problem in the radioactive environment. First, a more complicated radiation dose model is constructed, considering difficulty levels at each operating point. Based on this model, the multi-objective operating planning problem is converted to a [...] Read more.

This paper aims to solve the multi-objective operating planning problem in the radioactive environment. First, a more complicated radiation dose model is constructed, considering difficulty levels at each operating point. Based on this model, the multi-objective operating planning problem is converted to a variant traveling salesman problem (VTSP). Second, with respect to this issue, a novel combinatorial algorithm framework, namely hyper-parameter adaptive genetic algorithm (HPAGA), integrating bio-inspired optimization with reinforcement learning, is proposed, which allows for adaptive adjustment of the hyperparameters of GA so as to obtain optimal solutions efficiently. Third, comparative studies demonstrate the superior performance of the proposed HPAGA against classical evolutionary algorithms for various TSP instances. Additionally, a case study in the simulated radioactive environment implies the potential application of HPAGA in the future. Full article

(This article belongs to the Special Issue Bio-Inspired Optimization Algorithms and Designs for Engineering Applications: 2nd Edition)

10 pages, 2508 KiB

Open AccessArticle

CDC’s Laboratory Activities to Support Newborn Screening for Spinal Muscular Atrophy

by Francis K. Lee, Christopher Greene, Kristina Mercer, Jennifer Taylor, Golriz Yazdanpanah, Robert Vogt, Rachel Lee, Carla Cuthbert and Suzanne Cordovado

Int. J. Neonatal Screen. 2024, 10(3), 51; https://doi.org/10.3390/ijns10030051 (registering DOI) - 17 Jul 2024

Abstract

Spinal muscular atrophy (SMA) was added to the HHS Secretary’s Recommended Uniform Screening Panel for newborn screening (NBS) in 2018, enabling early diagnosis and treatment of impacted infants to prevent irreversible motor neuron damage. In anticipation of supporting SMA newborn screening, scientists at [...] Read more.

Spinal muscular atrophy (SMA) was added to the HHS Secretary’s Recommended Uniform Screening Panel for newborn screening (NBS) in 2018, enabling early diagnosis and treatment of impacted infants to prevent irreversible motor neuron damage. In anticipation of supporting SMA newborn screening, scientists at the U.S. Centers for Disease Control and Prevention (CDC) have worked towards building resources for public health laboratories in four phases since 2013. In Phase 1, CDC established a real-time PCR assay, which uses a locked nucleic acid probe to attain the needed specificity, to detect SMN1 exon 7. In Phase 2, we developed quality assurance dried blood spot materials made with transduced lymphoblast cell lines established from de-identified SMA patients, carriers, and unaffected donors. In 2021, CDC implemented Phase 3, a proficiency testing program, that now supports 115 NBS labs around the world. We are currently completing Phase 4, which includes the implementation of an external SMA quality control material program. Also, during this time, CDC has provided individual technical assistance to NBS programs and bench training to NBS scientists during our annual molecular workshop. These CDC-led activities have contributed to the rapid and full implementation of SMA screening in all 50 U.S. states as of February 2024. Full article

(This article belongs to the Special Issue Newborn Screening for SMA—State of the Art)

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17 pages, 2517 KiB

Open AccessArticle

Morpho-Functional Analyses Demonstrate That Tyrosol Rescues Dexamethasone-Induced Muscle Atrophy

by Sara Salucci, Sabrina Burattini, Ilaria Versari, Alberto Bavelloni, Francesco Bavelloni, Davide Curzi, Michela Battistelli, Pietro Gobbi and Irene Faenza

J. Funct. Morphol. Kinesiol. 2024, 9(3), 124; https://doi.org/10.3390/jfmk9030124 (registering DOI) - 17 Jul 2024

Abstract

Prolonged exposure to high dosages of dexamethasone, which is a synthetic glucocorticoid and a well-known anti-inflammatory drug, may lead to an increase in reactive oxygen species production, contributing to muscle wasting. The prevention of muscle atrophy by ingestion of functional foods is an [...] Read more.

Prolonged exposure to high dosages of dexamethasone, which is a synthetic glucocorticoid and a well-known anti-inflammatory drug, may lead to an increase in reactive oxygen species production, contributing to muscle wasting. The prevention of muscle atrophy by ingestion of functional foods is an attractive issue. In the last decade, natural antioxidant compounds have been increasingly investigated as promising molecules able to counteract oxidative-stress-induced muscle atrophy. Recently, we have demonstrated the antioxidant properties of two main olive oil polyphenols also known for their anticancer and anti-inflammatory activities in different cell models. Here, the preventive effect of tyrosol on dexamethasone-induced muscle atrophy has been investigated by means of morpho-functional approaches in C2C12 myotubes. Dexamethasone-treated cells showed a reduced fiber size when compared to control ones. While long and confluent myotubes could be observed in control samples, those exposed to dexamethasone appeared as immature syncytia. Dysfunctional mitochondria and the accumulation of autophagic vacuoles contributed to myotube degeneration and death. Tyrosol administration before glucocorticoid treatment prevented muscle wasting and rescued mitochondrial and lysosomal functionality. These findings demonstrate that tyrosol attenuates dexamethasone-induced myotube damage, and encourage the use of this natural molecule in preclinical and clinical studies and in synergy with other functional foods or physical activity with the aim to prevent muscle atrophy. Full article

(This article belongs to the Section Functional Anatomy and Musculoskeletal System)

21 pages, 1175 KiB

Open AccessArticle

Two Acceleration-Layer Configuration Amendment Schemes of Redundant Robot Arms Based on Zhang Neurodynamics Equivalency

by Zanyu Tang, Mingzhi Mao, Yunong Zhang and Ning Tan

Biomimetics 2024, 9(7), 435; https://doi.org/10.3390/biomimetics9070435 (registering DOI) - 17 Jul 2024

Abstract

Two innovative acceleration-layer configuration amendment (CA) schemes are proposed to achieve the CA of constrained redundant robot arms. Specifically, by applying the Zhang neurodynamics equivalency (ZNE) method, an acceleration-layer CA performance indicator is derived theoretically. To obtain a unified-layer inequality constraint by transforming [...] Read more.

Two innovative acceleration-layer configuration amendment (CA) schemes are proposed to achieve the CA of constrained redundant robot arms. Specifically, by applying the Zhang neurodynamics equivalency (ZNE) method, an acceleration-layer CA performance indicator is derived theoretically. To obtain a unified-layer inequality constraint by transforming from angle-layer and velocity-layer constraints to acceleration-layer constraints, five theorems and three corollaries are theoretically derived and rigorously proved. Then, together with the unified acceleration-layer bound constraint, an enhanced acceleration-layer CA scheme specially considering three-layer time-variant physical limits is proposed, and a simplified acceleration-layer CA scheme considering three-layer time-invariant physical limits is also proposed. The proposed CA schemes are finally formulated in the form of standard quadratic programming and are solved by a projection neurodynamics solver. Moreover, comparative simulative experiments based on a four-link planar arm and a UR3 spatial arm are performed to verify the efficacy and superiority of the proposed CA schemes. At last, physical experiments are conducted on a real Kinova Jaco2 arm to substantiate the practicability of the proposed CA schemes. Full article

(This article belongs to the Special Issue Bio-Inspired Data-Driven Methods and Their Applications in Engineering Control, Optimization and AI)

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20 pages, 6297 KiB

Open AccessArticle

Task-Motion Planning System for Socially Viable Service Robots Based on Object Manipulation

by Jeongmin Jeon, Hong-ryul Jung, Nabih Pico, Tuan Luong and Hyungpil Moon

Biomimetics 2024, 9(7), 436; https://doi.org/10.3390/biomimetics9070436 (registering DOI) - 17 Jul 2024

Abstract

This paper presents a software architecture to implement a task-motion planning system that can improve human-robot interactions by including social behavior when social robots provide services related to object manipulation to users. The proposed system incorporates four main modules: knowledge reasoning, perception, task [...] Read more.

This paper presents a software architecture to implement a task-motion planning system that can improve human-robot interactions by including social behavior when social robots provide services related to object manipulation to users. The proposed system incorporates four main modules: knowledge reasoning, perception, task planning, and motion planning for autonomous service. This system adds constraints to the robot motions based on the recognition of the object affordance from the perception module and environment states from the knowledge reasoning module. Thus, the system performs task planning by adjusting the goal of the task to be performed, and motion planning based on the functional aspects of the object, enabling the robot to execute actions consistent with social behavior to respond to the user’s intent and the task environment. The system is verified through simulated experiments consisting of several object manipulation services such as handover and delivery. The results show that, by using the proposed system, the robot can provide different services depending on the situation, even if it performs the same tasks. In addition, the system demonstrates a modular structure that enables the expansion of the available services by defining additional actions and diverse planning modules. Full article

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16 pages, 2099 KiB

Open AccessArticle

Modeling of the Human Cardiovascular System: Implementing a Sliding Mode Observer for Fault Detection and Isolation

by Dulce A. Serrano-Cruz, Latifa Boutat-Baddas, Mohamed Darouach, Carlos M. Astorga-Zaragoza and Gerardo V. Guerrero Ramírez

Math. Comput. Appl. 2024, 29(4), 57; https://doi.org/10.3390/mca29040057 (registering DOI) - 17 Jul 2024

Abstract

This paper presents a mathematical model of the cardiovascular system (CVS) designed to simulate both normal and pathological conditions within the systemic circulation. The model introduces a novel representation of the CVS through a change of coordinates, transforming it into the “quadratic normal [...] Read more.

This paper presents a mathematical model of the cardiovascular system (CVS) designed to simulate both normal and pathological conditions within the systemic circulation. The model introduces a novel representation of the CVS through a change of coordinates, transforming it into the “quadratic normal form”. This model facilitates the implementation of a sliding mode observer (SMO), allowing for the estimation of system states and the detection of anomalies, even though the system is linearly unobservable. The primary focus is on identifying valvular heart diseases, which are significant risk factors for cardiovascular diseases. The model’s validity is confirmed through simulations that replicate hemodynamic parameters, aligning with existing literature and experimental data. Full article

(This article belongs to the Special Issue Numerical and Evolutionary Optimization 2024)

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4 pages, 167 KiB

Open AccessEditorial

Editorial for the Special Issue: “Biomimicry and Functional Materials—First, Second, and Third Editions”

by Tun Naw Sut and Bo Kyeong Yoon

Biomimetics 2024, 9(7), 437; https://doi.org/10.3390/biomimetics9070437 (registering DOI) - 17 Jul 2024

Abstract

Nature has long been a source of inspiration for innovation in materials science [...] Full article

(This article belongs to the Special Issue Biomimicry and Functional Materials: 3rd Edition)

15 pages, 5522 KiB

Open AccessFeature PaperArticle

Silk Fibroin-Enriched Bioink Promotes Cell Proliferation in 3D-Bioprinted Constructs

by Sara Lipari, Pasquale Sacco, Eleonora Marsich and Ivan Donati

Gels 2024, 10(7), 469; https://doi.org/10.3390/gels10070469 (registering DOI) - 17 Jul 2024

Abstract

Three-dimensional (3D) bioprinting technology enables the controlled deposition of cells and biomaterials (i.e., bioink) to easily create complex 3D biological microenvironments. Silk fibroin (SF) has recently emerged as a compelling bioink component due to its advantageous mechanical and biological properties. This study reports [...] Read more.

Three-dimensional (3D) bioprinting technology enables the controlled deposition of cells and biomaterials (i.e., bioink) to easily create complex 3D biological microenvironments. Silk fibroin (SF) has recently emerged as a compelling bioink component due to its advantageous mechanical and biological properties. This study reports on the development and optimization of a novel bioink for extrusion-based 3D bioprinting and compares different bioink formulations based on mixtures of alginate methacrylate (ALMA), gelatin and SF. The rheological parameters of the bioink were investigated to predict printability and stability, and the optimal concentration of SF was selected. The bioink containing a low amount of SF (0.002% w/V) was found to be the best formulation. Light-assisted gelation of ALMA was exploited to obtain the final hydrogel matrix. Rheological analyses showed that SF-enriched hydrogels exhibited greater elasticity than SF-free hydrogels and were more tolerant to temperature fluctuations. Finally, MG-63 cells were successfully bioprinted and their viability and proliferation over time were analyzed. The SF-enriched bioink represents an excellent biomaterial in terms of printability and allows high cell proliferation over a period of up to 3 weeks. These data confirm the possibility of using the selected formulation for the successful bioprinting of cells into extracellular matrix-like microenvironments. Full article

(This article belongs to the Special Issue Feature Papers in Chemistry and Physics of Biological Gels)

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18 pages, 1190 KiB

Open AccessArticle

Swelling, Protein Adsorption, and Biocompatibility of Pectin–Chitosan Hydrogels

by Sergey Popov, Nikita Paderin, Elizaveta Chistiakova, Alisa Sokolova, Ilya V. Konyshev, Vladislav S. Belozerov and Andrey A. Byvalov

Gels 2024, 10(7), 472; https://doi.org/10.3390/gels10070472 (registering DOI) - 17 Jul 2024

Abstract

The study aims to determine how chitosan impacts pectin hydrogel’s ability to attach peritoneal leukocytes, activate complement, induce hemolysis, and adsorb blood proteins. The hydrogels PEC-Chi0, PEC-Chi25, PEC-Chi50, and PEC-Chi75 were prepared by placing a mixture solution of 4% pectin and 4% chitosan [...] Read more.

The study aims to determine how chitosan impacts pectin hydrogel’s ability to attach peritoneal leukocytes, activate complement, induce hemolysis, and adsorb blood proteins. The hydrogels PEC-Chi0, PEC-Chi25, PEC-Chi50, and PEC-Chi75 were prepared by placing a mixture solution of 4% pectin and 4% chitosan in a ratio of 4:0, 3:1, 2:2, and 1:3 in a solution of 1.0 M CaCl₂. Chitosan was found to modify the mechanical properties of pectin–calcium hydrogels, such as hardness and cohesiveness-to-adhesiveness ratio. Chitosan in the pectin–calcium hydrogel caused pH-sensitive swelling in Hanks’ solution. The PEC-Chi75 hydrogel was shown to adsorb serum proteins at pH 7.4 to a greater extent than other hydrogels. PEC-Chi75’s strong adsorption capacity was related to lower peritoneal leukocyte adherence to its surface when compared to other hydrogels, showing improved biocompatibility. Using the optical tweezers approach, it was shown that the force of interaction between pectin–chitosan hydrogels and plasma proteins increased from 10 to 24 pN with increasing chitosan content from 0 to 75%. Thus, the properties of pectin–calcium hydrogel, which determine interactions with body tissues after implantation, are improved by the addition of chitosan, making pectin–chitosan hydrogel a promising candidate for smart biomaterial development. Full article

(This article belongs to the Special Issue Physically Cross-Linked Gels and Their Applications)

14 pages, 7042 KiB

Open AccessArticle

Sol–Gel Synthesis of TiO₂ with Pectin and Their Efficiency in Solar Cells Sensitized by Quantum Dots

by Jean Flores-Gómez, Silvia Mota-Macías, Juan P. Guerrero-Jiménez, Victor Hugo Romero-Arellano and Juan Morales-Rivera

Gels 2024, 10(7), 470; https://doi.org/10.3390/gels10070470 (registering DOI) - 17 Jul 2024

Abstract

In this study, titanium oxide TiO₂ nanoparticles were produced using the sol–gel approach of green synthesis with pectin as the reducing agent. The synthetized TiO₂ nanoparticles with pectin were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), visible light absorption [...] Read more.

In this study, titanium oxide TiO₂ nanoparticles were produced using the sol–gel approach of green synthesis with pectin as the reducing agent. The synthetized TiO₂ nanoparticles with pectin were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), visible light absorption (UV–Vis) and the BET method. The structure and morphology of the TiO₂ powder were described with SEM, revealing uniform monodisperse grains with a distribution of 80% regarding sizes < 250 nm; the resulting crystal phase of synthetized TiO₂ was identified as an anatase and rutile phase with a crystallinity size estimated between 27 and 40 nm. Also, the surface area was determined by nitrogen adsorption–desorption using the Brown–Emmet–Teller method, with a surface area calculated as 19.56 m²/g, typical of an IV type isotherm, indicating mesoporous NPs. UV–Vis spectra showed that sol–gel synthesis reduced the band gap from the 3.2 eV common value to 2.22 eV after estimating the optical band gap energy using the adsorption coefficient; this translates to a possible extended photo response to the visible region, improving photoactivity. In addition, the power conversion of the photoelectrode was compared based on similar assembly techniques of TiO₂ electrode deposition. Quantum dot crystals were deposited ionically on the electrode surface, as two different paste formulations based on a pectin emulsifier were studied for layer deposition. The results confirm that the TiO₂ paste with TiO₂-synthesized powder maintained good connections between the nanocrystalline mesoporous grains and the deposited layers, with an efficiency of 1.23% with the transparent paste and 2.27% with the opaque paste. These results suggest that pectin could be used as a low-cost, functional sol–gel catalysis agent for the synthesis of controlled NPs of metal oxide. It demonstrates interesting optical properties, such as an increase in photo response, suggesting further applications to photocatalysts and biomedical features. Full article

(This article belongs to the Special Issue Chemical Properties and Application of Gel Materials)

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17 pages, 6718 KiB

Open AccessArticle

Incorporation of Locust Bean Gum and Solid Lipid Microparticles as Strategies to Improve the Properties and Stability of Calcium-Rich Soy Protein Isolate Gels

by Thais C. Brito-Oliveira, Ana Clara M. Cavini, Leticia S. Ferreira, Izabel C. F. Moraes and Samantha C. Pinho

Gels 2024, 10(7), 467; https://doi.org/10.3390/gels10070467 (registering DOI) - 17 Jul 2024

Abstract

The present study aimed to investigate the properties of calcium-rich soy protein isolate (SPI) gels (14% SPI; 100 mM CaCl₂), the effects of incorporating different concentrations locust bean gum (LBG) (0.1–0.3%, w/v) to the systems and the stability [...] Read more.

The present study aimed to investigate the properties of calcium-rich soy protein isolate (SPI) gels (14% SPI; 100 mM CaCl₂), the effects of incorporating different concentrations locust bean gum (LBG) (0.1–0.3%, w/v) to the systems and the stability of the obtained gels. Also, the incorporation of solid lipid microparticles (SLMs) was tested as an alternative strategy to improve the system’s stability and, therefore, potential to be applied as a product prototype. The gels were evaluated regarding their visual aspect, rheological properties, water-holding capacities (WHCs) and microstructural organizations. The CaCl₂-induced gels were self-supported but presented low WHC (40.0% ± 2.2) which was improved by LBG incorporation. The obtained mixed system, however, presented low stability, with high syneresis after 10 days of storage, due to microstructural compaction. The gels’ stability was improved by SLM incorporation, which decreased the gelled matrices’ compaction and syneresis for more than 20 days. Even though the rheological properties of the emulsion-filled gels (EFGs) were very altered due to the ageing process (which may affect the sensory perception of a future food originated from this EFG), the incorporation of SLMs increased the systems potential to be applied as a calcium-rich product prototype. Full article

(This article belongs to the Special Issue Recent Advances on the Use of Different Gels Type in the Food Industry)

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14 pages, 2374 KiB

Open AccessReview

Micelle-Containing Hydrogels and Their Applications in Biomedical Research

by Jinghua Wu, Huapeng Li, Nan Zhang and Qingfei Zheng

Gels 2024, 10(7), 471; https://doi.org/10.3390/gels10070471 (registering DOI) - 17 Jul 2024

Abstract

Hydrogels are one of the most commonly used materials in our daily lives, which possess crosslinked three-dimensional network structures and are capable of absorbing large amounts of fluid. Due to their outstanding properties, such as flexibility, tunability, and biocompatibility, hydrogels have been widely [...] Read more.

Hydrogels are one of the most commonly used materials in our daily lives, which possess crosslinked three-dimensional network structures and are capable of absorbing large amounts of fluid. Due to their outstanding properties, such as flexibility, tunability, and biocompatibility, hydrogels have been widely employed in biomedical research and clinics, especially in on-demand drug release. However, traditional hydrogels face various limitations, e.g., the delivery of hydrophobic drugs due to their highly hydrophilic interior environment. Therefore, micelle-containing hydrogels have been designed and developed, which possess both hydrophilic and hydrophobic microenvironments and enable the storage of diverse cargos. Based on the functionalities of micelles, these hydrogels can be classified into micelle-doped and chemically/physically crosslinked types, which were reported to be responsive to varied stimuli, including temperature, pH, irradiation, electrical signal, magnetic field, etc. Here, we summarize the research advances of micelle-containing hydrogels and provide perspectives on their applications in the biomedical field based on the recent studies from our own lab and others. Full article

(This article belongs to the Special Issue Designing Hydrogels for Sustained Delivery of Therapeutic Agents)

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Graphical abstract

15 pages, 4651 KiB

Open AccessArticle

Influence of Thermal Treatment on the Chemical and Structural Properties of Geopolymer Gels Doped with Nd₂O₃ and Sm₂O₃

by Miloš Nenadović, Sanja Knežević, Marija Ivanović, Snežana Nenadović, Danilo Kisić, Maja Popović and Jelena Potočnik

Gels 2024, 10(7), 468; https://doi.org/10.3390/gels10070468 (registering DOI) - 17 Jul 2024

Abstract

In this research, the influence of the thermal treatment of geopolymer gels at 300 °C, 600 °C and 900 °C when incorporated with 5% rare earth elements (REEs) in the form of (GP-Sm) Sm₂O₃ and (GP-Nd) Nd₂O₃ [...] Read more.

In this research, the influence of the thermal treatment of geopolymer gels at 300 °C, 600 °C and 900 °C when incorporated with 5% rare earth elements (REEs) in the form of (GP-Sm) Sm₂O₃ and (GP-Nd) Nd₂O₃ was investigated. Changes in the chemical and structural properties of the geopolymer gels during thermal treatment for 1 h were monitored. Physico-chemical characterization was performed using the following methods: diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), scanning electron microscopy with energy dispersive spectrometry (SEM-EDS), and X-ray photoelectron spectroscopy (XPS). Besides the characterization of the fundamental properties, some practical macroscopic properties were analyzed as well: sorptivity, open porosity, and Archimedean density. The stretching vibrations of Nd–O–Si and Sm–O–Si were confirmed at a value of around 680 cm⁻¹and an Nd–O–Si absorption band at a higher value, together with the most dominant band of Si–O stretching vibration similar for all the samples. No significant chemical changes occurred. Structural analysis showed that for GP-Nd, the largest pore diameter was obtained at 900 °C, while for GP-Sm, the largest pore diameter was obtained at 600 °C. EDS confirmed the amount of dopant to be about 5%. X-ray photoelectron spectroscopy showed that for GP-Nd, the ratio of Si and Al changed the most, while for GP-Sm, the ratio of Si and Al decreased with increasing temperature. The contributions of both dopants in the GP-gel structure remained almost unchanged and stable at high temperatures. The atomic percentages obtained by XPS analysis were in accordance with the expected trend; the amount of Si increased with the temperature, while the amount of Al decreased with increasing temperature. The sorptivity and open porosity showed the highest values at 600 °C, while the density of both geopolymers decreased linearly with increasing temperature. Full article

(This article belongs to the Special Issue Chemical Properties and Application of Gel Materials)

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28 pages, 15256 KiB

Open AccessArticle

A Computational Analysis of Turbocharger Compressor Flow Field with a Focus on Impeller Stall

by Deb K. Banerjee, Ahmet Selamet and Pranav Sriganesh

Fluids 2024, 9(7), 162; https://doi.org/10.3390/fluids9070162 (registering DOI) - 17 Jul 2024

Abstract

Understanding the flow instabilities encountered by the turbocharger compressor is an important step toward improving its overall design for performance and efficiency. While an experimental study using Particle Image Velocimetry was previously conducted to examine the flow field at the inlet of the [...] Read more.

Understanding the flow instabilities encountered by the turbocharger compressor is an important step toward improving its overall design for performance and efficiency. While an experimental study using Particle Image Velocimetry was previously conducted to examine the flow field at the inlet of the turbocharger compressor, the present work complements that effort by analyzing the flow structures leading to stall instability within the same impeller. Experimentally validated three-dimensional computational fluid dynamics predictions are carried out at three discrete mass flow rates, including 77 g/s (stable, maximum flow condition), 57 g/s (near peak efficiency), and 30 g/s (with strong reverse flow from the impeller) at a fixed rotational speed of 80,000 rpm. Large stationary stall cells were observed deep within the impeller at 30 g/s, occupying a significant portion of the blade passage near the shroud between the suction surface of the main blades and the pressure surface of the splitter blades. These stall cells are mainly created when a substantial portion of the inlet core flow is unable to follow the impeller’s axial to radial bend against the adverse pressure gradient and becomes entrained by the reverse flow and the tip leakage flow, giving rise to a region of low-momentum fluid in its wake. This phenomenon was observed to a lesser extent at 57 g/s and was completely absent at 77 g/s. On the other hand, the inducer rotating stall was found to be most dominant at 57 g/s. The entrainment of the tip leakage flow by the core flow moving into the impeller, leading to the generation of an unstable, wavy shear layer at the inducer plane, was instrumental in the generation of rotating stall. The present analyses provide a detailed characterization of both stationary and rotating stall cells and demonstrate the physics behind their formation, as well as their effect on compressor efficiency. The study also characterizes the entropy generation within the impeller under different operating conditions. While at 77 g/s, the entropy generation is mostly concentrated near the shroud of the impeller with the core flow being almost isentropic, at 30 g/s, there is a significant increase in the area within the blade passage that shows elevated entropy production. The tip leakage flow, its interaction with the blades and the core forward flow, and the reverse flow within the impeller are found to be the major sources of irreversibilities. Full article

(This article belongs to the Special Issue Computational Fluid Dynamics in Fluid Machinery)

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12 pages, 3362 KiB

Open AccessArticle

Alternaria alternata Pathogen from Cuscuta japonica Could Serve as a Potential Bioherbicide

by Yinglong Liu, Ayesha Ahmed, Shahzad Munir, Lei Chen, Pengfei He, Yueqiu He, Ping Tang, Baohua Kong, Yixin Wu and Pengbo He

J. Fungi 2024, 10(7), 494; https://doi.org/10.3390/jof10070494 (registering DOI) - 17 Jul 2024

Abstract

Dodder (Cuscuta spp.) is a dangerous parasitic plant that causes serious damage to crop production and is challenging to eliminate. Herbicide application is a common strategy to control dodder in the field, but it is costly, ineffective, and further results in hazardous [...] Read more.

Dodder (Cuscuta spp.) is a dangerous parasitic plant that causes serious damage to crop production and is challenging to eliminate. Herbicide application is a common strategy to control dodder in the field, but it is costly, ineffective, and further results in hazardous outcomes. Therefore, our study aims to identify the potential pathogens in naturally occurring dodder infections which may provide efficient biocontrol options. In this regard, the pathogens were isolated from the infected plants, their pathogenicity was validated through inoculation, and the optimal culture conditions for their growth were identified by determining the pathogenicity difference. The pathogenicity range was determined in vitro using the leaves of common horticultural plants and crops. Furthermore, a small range of horticultural plants parasitized by Cuscuta reflexa in the field were inoculated with the pathogen to determine their biosafety and biocontrol potential, and the pathogens were identified by morphological and molecular characterization. We found 7 strains that were isolated after pathogen enrichment culture. Among them, Cbp6 and Cbp7 showed the highest pathogenicity against C. reflexa. After testing the inoculation of more than 50 species of plants, only 9 species showed varying degrees of lesions on leaves, which proved the high biosafety for common plants. Field spraying of these pathogens showed a good control effect on C. reflexa after 21 days; the disease severityreached 66.0%, while its host plant did not display obvious symptoms. In conclusion, the pathogens Cbp6 and Cbp7 were identified as Alternaria alternata, and the results of this study provide a theoretical basis for the biological control of dodder. Full article

(This article belongs to the Section Fungal Genomics, Genetics and Molecular Biology)

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30 pages, 2093 KiB

Open AccessArticle

Productivity and Keynes’s 15-Hour Work Week Prediction for 2030: An Alternative, Macroeconomic Analysis for the United States

by Edoardo Beretta, Aurelio F. Bariviera, Marco Desogus, Costanza Naguib and Sergio Rossi

J. Risk Financial Manag. 2024, 17(7), 306; https://doi.org/10.3390/jrfm17070306 (registering DOI) - 17 Jul 2024

Abstract

This paper analyses Keynes’s 1930 prediction that technical advances would cut people’s working week to 15 h by 2030 and investigates why actual working hours are significantly higher in the United States. Elaborating on Keynes’s forecast to provide a general productivity formula while [...] Read more.

This paper analyses Keynes’s 1930 prediction that technical advances would cut people’s working week to 15 h by 2030 and investigates why actual working hours are significantly higher in the United States. Elaborating on Keynes’s forecast to provide a general productivity formula while keeping its simplicity, we ran tests on macro-data from 1929 to 2019 and on estimates for 2030, demonstrating that productivity is surprisingly still insufficient to allow for a reduction in working hours across the US economy. This finding represents a substantial contribution to the literature, which has mostly explained long working hours by means of new consumer needs. Even by using microdata, we show that consumption does not explain the stickiness of working hours to the bottom. Hence, this paper combines a macroeconomic, logical-analytical approach based on historical time series with rigorously constructed time series at the microeconomic level. Finally, we also provide policies to narrow the productivity differential to Keynes’s prediction for 2030 while fostering work-life balance and sustainable growth. To understand long working hours in the US despite technical advances—this being one of our main findings—productivity remains crucial. Full article

(This article belongs to the Special Issue Emerging Trends in International Macroeconomics: Insights and Challenges)

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