Hasil untuk "General. Including alchemy"

L. Humphrey, R. Fu, D. Buckley et al.

Tanyamon Petcharat, Manat Chaijan, Sylvia Indriani et al.

Fish gelatin (FG) is a promising alternative to mammalian gelatin but is limited by poor gelling ability, low gel strength, and inability to set at room temperature. This study evaluated the effects of furcellaran (FUR), a gelling agent, on the structural and physicochemical properties of FG gels at different substitution levels (25–100%). The addition of 25% FUR improved gel strength and hardness. However, higher FUR levels (>50%) led to reduced springiness and increased syneresis. Intermolecular force measurements revealed that ionic and hydrogen bonds were crucial in the FG/FUR gel system, with higher levels of FUR promoting stronger ionic and hydrogen bonding. Color changes were observed with decreased <i>L*</i> and increased <i>b*</i> and ∆<i>E*</i> values as FUR levels rose. Gelling and melting points also increased proportionally with FUR content. Microstructural analysis showed denser gel networks with smaller gaps upon FUR incorporation. SAXS analysis confirmed enhanced structural conformation with higher FUR levels. An appropriate level of FUR added (25%) could therefore improve gelling properties via increasing gel strength and gelling temperature without negative effects on springiness and syneresis of resulting gel.

Julia E. Ralph, Bradley J. Lauck, Charles B. Colson et al.

As tissue engineering and regenerative medicine (TERM) continues to revolutionize medicine and surgery, there is also growing interest in applying these advancements to foot and ankle surgery. The purpose of this article is to provide a comprehensive review of the types of gel scaffolds and templates, their applications in foot and ankle surgery, the challenges with current utilization, and the future directions of TERM in foot and ankle surgery. With multiple compelling scaffold prospects across the numerous natural, synthetic, and hybrid polymers currently utilized in TERM, promising results have been described in the treatment of osteoarthritis (OA) and osteochondral lesions (OCLs). However, concerns with material biocompatibility, structural integrity, feasibility during surgery, and degradation still exist and limit the extent of utilization. As researchers continue to develop enhanced polymers and formulations that address current issues, there are many opportunities to increase applications across foot and ankle surgery.

Xiaohu Qiang, Zhu Hu, Wang Liu et al.

Natural biomaterials are widely used in the construction of cartilage tissue engineering due to their excellent biocompatibility, easy degradation, and ability to degrade products to be absorbed by the human body. However, due to their poor mechanical properties, it is usually necessary to composite them with other materials to prepare biological scaffolds that meet the expected requirements. This study used freeze-drying technology to introduce calcium polyphosphate fibres (CPPFs) into a chitosan (CS) matrix to prepare composite scaffolds with better performance. CPPF was used as a filler and inorganic skeleton in the CS/CPPF composite to improve the properties of the CS-based scaffold. With little change in porosity, the compressive strength of the CS/CPPF composite scaffold increased from 0.172 MPa of chitosan to 0.332 MPa with the increase in CPPF addition. The water absorption rate of the composite scaffold decreased from 1297.42% to 935.37%. In vitro degradation experiments revealed that CPPF accelerated the degradation of the scaffold and generated calcium phosphate and nano-hydroxyapatite compounds during the degradation process. According to our cytotoxicity testing, the CS/CPPF composite scaffolds exhibited good biocompatibility and could enhance cell proliferation. This method of incorporating CPPF into CS provides important reference values for the application of CPPF in other natural bone tissue engineering scaffold materials.

Yoshitaka Miyamoto

This Special Issue provides an overview of “Global Excellence in Bioactive Gels” [...]

Levi M. Olevsky, Mason G. Jacques, Katherine R. Hixon

Porous gels are frequently utilized as cell scaffolds in tissue engineering. Previous studies have highlighted the significance of scaffold pore size and pore orientation in influencing cell migration and differentiation. Moreover, there exists a considerable body of research focused on optimizing pore characteristics to enhance scaffold performance. However, current methods for numerical pore characterization typically involve expensive machines or manual size measurements using image manipulation software. In this project, our objective is to develop a user-friendly, versatile, and freely accessible software tool using Python scripting. This tool aims to streamline and objectify pore characterization, thereby accelerating research efforts and providing a standardized framework for researchers working with porous gels. Our group found that first-time users of PoreVision and ImageJ take similar amounts of time to use both programs; however, PoreVision is capable of handling larger datasets with reduced variability. Further, PoreVision users exhibited lower variability in area and orientation measurements compared to ImageJ, while perimeter variability was similar between the two. PoreVision showed higher variability in average measurements, likely due to its larger sample size and broader range of pore sizes, which may be missed in ImageJ’s manual scanning approach. By facilitating quantitative analysis of pore size, shape, and orientation, our software tool will contribute to a more comprehensive understanding of scaffold properties and their impact on cellular behavior. Ultimately, we aim to aid researchers in the field of tissue engineering with a user-friendly tool that enhances the reproducibility and reliability of pore characterization analyses.

Sujata Pandey, Gabriella Baki

Microemulsions have been commonly used with various permeation enhancers to improve permeability through the skin. The purpose of this study was to compare the release and permeation ability of two commonly used permeation enhancers—diethylene glycol monoethyl ether (DGME) and oleyl alcohol—by the changes in oil composition, the addition of a gelling agent, and water content using ibuprofen as a model drug. Four microemulsions were formulated, selection was based on ternary phase diagrams, and physicochemical properties were evaluated. The release and permeation of the microemulsion formulations were performed in vitro by Franz cell studies on a regenerated cellulose membrane and a Strat-M^® membrane, respectively, and the amount of ibuprofen permeated and released was analyzed by high-performance liquid chromatography (HPLC). All four microemulsions were compatible with the skin pH, and the average pH ranged from 4.9 to 5.6. The average droplet size of the microemulsions ranged from 119.8 to 153.3 nm. Drug release was significantly the highest from the gel-based microemulsions (59% and 64%, <i>p</i> < 0.05). However, there was a fourfold difference in drug permeation from these gels—a significantly higher permeation from the microemulsion-gel containing oleic acid and oleyl alcohol compared to the DGME formulation. These results indicated that the microemulsion-gel with oleyl alcohol as the permeation enhancer could be a preferable formulation approach for the topical administration of ibuprofen. These results highlight the need for optimization of the microemulsion formulation to confirm the permeation-enhancing effects of chosen permeation enhancers despite being a well-known permeation enhancer.

Caroline Ramos-Souza, Daniel Henrique Bandoni, Veridiana Vera de Rosso

Bigels are promising delivery systems for bioactive compounds, combining the properties of hydrogels and oleogels. Pequi carotenoids, characterized by their natural yellow fluorescence, hold potential to replace the artificial dye tartrazine in foods while simultaneously enhancing their functional properties. This study developed food-grade bigels with varying oleogel-to-hydrogel ratios (40%, 60%, 80% OG) to assess the pigmentation capacity of pequi carotenoid extracts. Hydrogel contained agar and xanthan gum, while oleogel comprised beeswax, lecithin, sunflower oil, and 400 μg/100 g carotenoid extract. Bigel color was analyzed using the CIELAB system. Linear and multiple regression models were applied to assess the influence of crosslinking time (1 vs. 12 h), extraction solvent (acetone vs. [BMIM][BF4]), saponification, and oleogel ratio on color parameters. The color of the carotenoid-enriched bigels was mainly influenced by the extraction solvent and the oleogel ratio, while saponification and crosslinking time had only minor impacts. Although changes in <i>L*</i>, <i>a*</i>, and <i>b*</i> were observed across samples, <i>ΔE*</i> values generally reflected low perceptibility. Notably, more evident color differences were associated with variations in solvent type and oleogel ratio. These findings contribute to a better understanding of how formulation parameters influence the pigmentation behavior and support the development of natural, visually appealing functional foods.

Michele Larocca, Giuseppe Floresta, Daniele Verderese et al.

The genetic material in living systems is mainly stored in DNA molecules, which in turn play a dominant biological role in relation to the coding and transfer of genetic information, the biosynthesis of proteins and RNA and the packaging and regulation of DNA expression and accessibility. These features, strictly dictated by the three-dimensional structure of DNA, are governed by non-covalent chemical interactions that drive the folding process of these biological macromolecules. The Main Mechanical Forces (MMFs) approach is a recently formulated calculation method, based on the accurate prediction of structural features of biomolecules through an in-depth assessment of the interplay between specific non-covalent chemical interactions and related mechanical forces developed during the folding process. By adopting the MMFs method in the context of nucleic acids, we report here the results obtained in terms of predicting three-dimensional DNA oligomer tertiary structures. To this end, we have developed tailored nucleic acid-specific equations, enabling to predict the torsion angles (with a relevant level of agreement with experimental values) of the phosphate-sugar backbone of the three model molecules A-, B- and Z- DNA used in this study. To increase the validity of this methodology, we have conducted RMSD measurements, indicating that there is a weak but rather acceptable match between the calculated vs. predicted A-DNA structure, whereas the prediction of the BII-DNA and Z-DNA tertiary structures was fully correct.

H. Alwael, E. MacHugh, M. S. El-Shahawi et al.

The current study reports on the impact of a series of functional alkoxysilanes on the wettability and structure of a well-established silicon/zirconium hybrid anticorrosion sol–gel coating. The selected functional alkoxysilanes comprise tetra ethylorthosilicate (TEOS), 3-glycidyloxypropyltrimethoxysilane (GPTMS), 3-aminopropyltriethoxysilane (APTES) and vinyltriethoxysilane (VTES) and are incorporated at various concentrations (1, 5, 10 and 20%) within the silicon/zirconium sol–gel material. The prepared materials are successfully processed as coatings and cured at different temperatures in the range of 100–150 °C. The characterisation of the structures and surfaces is performed by dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), silicon nuclear magnetic resonance spectroscopy (²⁹Si-NMR), atomic force microscopy (AFM) and static water contact angle (WCA). Structural characterisations (DLS, FTIR,²⁹Si-NMR) show that the functional alkoxysilanes effectively bind at the surface of the reference sol–gel material, resulting in the formation of functional core–shell nanoparticles. WCA results show that the hydrophobic properties of all materials decrease with curing temperature, and AFM analysis demonstrated that this behaviour is associated with a decrease in roughness. The physico-chemical processes taking place are critically assigned and discussed.

Miloš Nenadović, Sanja Knežević, Marija Ivanović et al.

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.

Max Dombrowski, Michael Herbst, Natalie Preisig et al.

The combination of lyotropic liquid crystals (LLCs) and low-molecular-weight gelators (LMWGs) for the formation of lyotropic liquid crystal gels (LLC gels) leads to a versatile and complex material combining properties of both parent systems. We gelled the calamitic nematic N_C phases of a binary and ternary system using the LMWG 3,5-bis-(5-hexylcarbamoyl-pentoxy)-benzoic acid hexyl ester (BHPB-6). This binary system consists of the surfactant <i>N</i>,<i>N</i>-dimethyl-<i>N</i>-ethyl-1-hexadecylammonium bromide (CDEAB) and water, whereas the ternary system consists of the surfactant <i>N</i>,<i>N</i>,<i>N</i>-trimethyl-<i>N</i>-tetradecylammonium bromide (C₁₄TAB), the cosurfactant <i>n</i>-decanol, and water. Though containing similar surfactants, the gelled N_C phases of the binary and ternary systems show differences in their visual and gel properties. The gelled N_C phase of the binary system remains clear for several days after preparation, whereas the gelled N_C phase of the ternary system turns turbid within 24 h. We investigated the time evolution of the gel strength with oscillation rheology measurements (a) within the first 24 h and (b) up to two weeks after gel formation. The shape of the fibers was investigated over different time scales with freeze fracture electron microscopy (FFEM). We demonstrate that despite their similarities, the two LLC gels also have distinct differences.

L. Jefferson, S. Golder, H. Essex et al.

Background The unadjusted gender pay gap in general practice is reported to be 33.5%. This reflects partly the differential rate at which women become partners, but evidence exploring gender differences in GPs’ career progression is sparse. Aim To explore factors affecting uptake of partnership roles, focusing particularly on gender differences. Design and setting Convergent mixed-methods research design using data from UK GPs. Method Secondary analysis of qualitative interviews and social media analysis of UK GPs’ Twitter commentaries, which informed the conduct of asynchronous online focus groups. Findings were combined using methodological triangulation. Results The sample comprised 40 GP interviews, 232 GPs tweeting about GP partnership roles, and seven focus groups with 50 GPs. Factors at individual, organisational, and national levels influence partnership uptake and career decisions of both men and women GPs. Desire for work–family balance (particularly childcare responsibilities) presented the greatest barrier, for both men and women, as well as workload, responsibility, financial investment, and risk. Greater challenges were, however, reported by women, particularly regarding balancing work–family lives, as well as prohibitive working conditions (including maternity and sickness pay) and discriminatory practices perceived to favour men and full-time GPs. Conclusion There are some long-standing gendered barriers that continue to affect the career decisions of women GPs. The relative attractiveness of salaried, locum, or private roles in general practice appears to discourage both men and women from partnerships presently. Promoting positive workplace cultures through strong role models, improved flexibility in roles, and skills training could potentially encourage greater uptake.

A. Siriwardena, Vanessa Botan, N. Williams et al.

Background Differential attainment has previously been suggested as being due to subjective bias because of racial discrimination in clinical skills assessments. Aim To investigate differential attainment in all UK general practice licensing tests comparing ethnic minority with White doctors. Design and setting Observational study of doctors in GP specialty training in the UK. Method Data were analysed from doctors’ selection in 2016 to the end of GP training, linking selection, licensing, and demographic data to develop multivariable logistic regression models. Predictors of pass rates were identified for each assessment. Results A total of 3429 doctors entering GP specialty training in 2016 were included, with doctors of different sex (female 63.81% versus male 36.19%), ethnic group (White British 53.95%, minority ethnic 43.04%, and mixed 3.01%), country of primary medical qualification (UK 76.76% versus non-UK 23.24%), and declared disability (disability declared 11.98% versus not declared 88.02%). Multi-Specialty Recruitment Assessment (MSRA) scores were highly predictive for GP training end-point assessments, including the Applied Knowledge Test (AKT), Clinical Skills Assessment (CSA), Recorded Consultation Assessment (RCA), and Workplace-Based Assessment (WPBA) and Annual Review of Competency Progression (ARCP). Ethnic minority doctors did significantly better compared with White British doctors in the AKT (odds ratio [OR] 2.05, 95% confidence interval [CI] = 1.03 to 4.10, P = 0.042). There were no significant differences on other assessments: CSA (OR 0.72, 95% CI = 0.43 to 1.20, P = 0.201), RCA (OR 0.48, 95% CI = 0.18 to 1.32, P = 0.156), or WPBA—ARCP (OR 0.70, 95% CI = 0.49 to 1.01, P = 0.057). Conclusion Ethnic background did not reduce the chance of passing GP licensing tests once sex, place of primary medical qualification, declared disability, and MSRA scores were accounted for.

Chao Ma, Shuyi Peng, Lian Chen et al.

Stimuli-responsive color-changing and shape-changing hydrogels are promising intelligent materials for visual detections and bio-inspired actuations, respectively. However, it is still an early stage to integrate the color-changing performance and shape-changing performance together to provide bi-functional synergistic biomimetic devices, which are difficult to design but will greatly expand further applications of intelligent hydrogels. Herein, we present an anisotropic bi-layer hydrogel by combining a pH-responsive rhodamine-B (RhB)-functionalized fluorescent hydrogel layer and a photothermal-responsive shape-changing melanin-added poly (N-isopropylacrylamide) (PNIPAM) hydrogel layer with fluorescent color-changing and shape-changing bi-functional synergy. This bi-layer hydrogel can obtain fast and complex actuations under irradiation with 808 nm near-infrared (NIR) light due to both the melanin-composited PNIPAM hydrogel with high efficiency of photothermal conversion and the anisotropic structure of this bi-hydrogel. Furthermore, the RhB-functionalized fluorescent hydrogel layer can provide rapid pH-responsive fluorescent color change, which can be integrated with NIR-responsive shape change to achieve bi-functional synergy. As a result, this bi-layer hydrogel can be designed using various biomimetic devices, which can show the actuating process in the dark for real-time tracking and even mimetic starfish to synchronously change both the color and shape. This work provides a new bi-layer hydrogel biomimetic actuator with color-changing and shape-changing bi-functional synergy, which will inspire new strategies for other intelligent composite materials and high-level biomimetic devices.

Shanshan Wang, Deqing Zhou, Nan Liu et al.

Acid-solubilized (ASC) and pepsin-solubilized collagen (PSC) extracted at 4 °C (ASC-4 and PSC-4), 12 °C (ASC-12 and PSC-12), and 20 °C (ASC-20 and PSC-20) from the skin of farmed pufferfish (<i>Takifugu obscurus</i>) was characterized by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier-transform infrared spectroscopy (FTIR), and fibril-forming tests. The results indicate that extraction at 12 °C can effectively improve the extraction efficiency of natural collagen compared with extraction at 4 °C. However, extraction at 20 °C results in a decrease in molecular integrity, thus, inducing the resultant collagen to degrade or even lose fibril-forming ability. Transmission electron microscope (TEM) images revealed that ASC-4, PSC-4, ASC-12, and PSC-12 can assemble into fibrils with D-periodicities, and ASC-20 associated into molecular aggregates alongside partial D-banded fibrils, while no well-defined fibrils were observed in PSC-20. Scanning electron microscope (SEM) analysis confirmed the well-defined fibril morphologies of ASC-4, PSC-4, ASC-12, and PSC-12 with imino acid contents between 190.0 and 197.8 residues/1000 residues. The denaturation temperature of ASC-4, PSC-4, ASC-12 and PSC-12 was 30.0, 27.6, 25.9 and 22.7 °C, respectively. This study indicates that ASC and PSC extracted at 4 °C and 12 °C could be alternatives to terrestrial collagens for industrial applications.

Yang Yang, Zixun Wang, Yuanyuan Xu et al.

Collagen and chitosan are frequently used natural biomaterials in tissue engineering. However, most collagen is derived from animal tissue, with inconsistent quality and pathogen transmittance risks. In this context, we aimed to use a reliable Type-III recombinant human collagen (RHC) as an alternative biomaterial together with chitosan to develop novel photo-responsive bioinks for three-dimensional (3D) bioprinting. RHC was modified with methacrylic anhydride to obtain the RHC methacryloyl (RHCMA) and mixed with acidified chitosan (CS) to form composites CS-RHCMA. The characterizations demonstrated that the mechanical properties and the degradation of the bioinks were tunable by introducing the CS. The printabilities improved by adding CS to RHCMA, and various structures were constructed via extrusion-based 3D printing successfully. Moreover, in vitro tests confirmed that these CS-RHCMA bioinks were biocompatible as human umbilical vein endothelial cells (HUVECs) were sustained within the constructs post-printing. The results from the current study illustrated a well-established bioinks system with the potential to construct different tissues through 3D bioprinting.

Ricardo N. Pereira, Rui M. Rodrigues

The increased pressure over soils imposed by the need for agricultural expansion and food production requires development of sustainable and smart strategies for the efficient use of resources and food nutrients. In accordance with worldwide transformative polices, it is crucial to design sustainable systems for food production aimed at reducing environmental impact, contributing to biodiversity preservation, and leveraging a bioeconomy that supports circular byproduct management. Research on the use of emergent protein sources to develop value-added foods and biomaterials is in its infancy. This review intends to summarize recent research dealing with technological functionality of underused protein fractions, recovered from microbial biomass and food waste sources, addressing their potential applications but also bottlenecks. Protein-based materials from dairy byproducts and microalgae biomass gather promising prospects of use related to their techno-functional properties. However, a balance between yield and functionality is needed to turn this approach profitable on an industrial scale basis. In this context, downstream processing should be strategically used and properly integrated. Food solutions based on microbial proteins will expand in forthcoming years, bringing the opportunity to finetune development of novel protein-based biomaterials.

Sophie Dani, Tilman Ahlfeld, Franziska Albrecht et al.

Highly viscous bioinks offer great advantages for the three-dimensional fabrication of cell-laden constructs by microextrusion printing. However, no standardised method of mixing a high viscosity biomaterial ink and a cell suspension has been established so far, leading to non-reproducible printing results. A novel method for the homogeneous and reproducible mixing of the two components using a mixing unit connecting two syringes is developed and investigated. Several static mixing units, based on established mixing designs, were adapted and their functionality was determined by analysing specific features of the resulting bioink. As a model system, we selected a highly viscous ink consisting of fresh frozen human blood plasma, alginate, and methylcellulose, and a cell suspension containing immortalized human mesenchymal stem cells. This bioink is crosslinked after fabrication. A pre-crosslinked gellan gum-based bioink providing a different extrusion behaviour was introduced to validate the conclusions drawn from the model system. For characterisation, bioink from different zones within the mixing device was analysed by measurement of its viscosity, shape fidelity after printing and visual homogeneity. When taking all three parameters into account, a comprehensive and reliable comparison of the mixing quality was possible. In comparison to the established method of manual mixing inside a beaker using a spatula, a significantly higher proportion of viable cells was detected directly after mixing and plotting for both bioinks when the mixing unit was used. A screw-like mixing unit, termed “HighVisc”, was found to result in a homogenous bioink after a low number of mixing cycles while achieving high cell viability rates.

Patrik Berg, Carsten Dieter Prowald, Dirk Kuckling

Several methods to increase the mechanical and swelling properties of Poly(<i>N</i>-isopropylacrylamide) gels are known. In this study different methods were combined to systematically alter the gel properties. The combination of nanocomposite and cryo gels as well as silica post modification was used to modulate the gel strength. This new cryo-clay-silica gel based on <i>N</i>-isopropylacrylamide was investigated in respect to degree of swelling, kinetic of thermo responsive behavior and tensile strength. Here, the properties of new cryo-clay-silica gel were compared with properties of clay-, silica-clay and cryo-clay gels.