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RSC Advances Jun 2024Halogen-halogen interactions play a pivotal role in the formation and stability of supramolecular assemblies. Herein, we investigate the assembly dynamics and...
Halogen-halogen interactions play a pivotal role in the formation and stability of supramolecular assemblies. Herein, we investigate the assembly dynamics and dissociation pathways of linear supramolecular polymers based on pillar[5]arene-mediated by guest halogen-halogen interactions (C-X × X-C) in both the solution and solid states. The structure of the solid-state supramolecular assembly was determined by single-crystal X-ray diffraction analysis. The binding affinities of four different 1,4-dihalobutane guests with pillar[5]arene were investigated by H NMR spectroscopic titration and isothermal titration calorimetry (ITC). The formation of the halogen-bonded linear supramolecular polymer in solution was demonstrated using diffusion-ordered spectroscopy (DOSY) and ITC. Our findings highlight the dependence of the dissociation process on halogen nature within the encapsulated guest, revealing that the process is entropically driven (Δ = 27.12 kJ mol) and enthalpically disfavored (Δ = 9.99 kJ mol). Moreover, the disassembly of supramolecular polymers promoted by N-containing compounds was investigated using H NMR spectroscopy and ITC, revealing that the process is driven both enthalpically (Δ = -2.64 kJ mol) and entropically (Δ = 15.70 kJ mol). Notably, the data suggest the formation of N⋯I bonding interactions at both ends of the inclusion guest, elucidating the intricate interplay of halogen interactions and host-guest chemistry in supramolecular polymer systems.
PubMed: 38946765
DOI: 10.1039/d4ra03769c -
Materials Horizons Jul 2024Contrary to previous results, a unique anti-correlation effect of the alkyl chain size on the photovoltaic performance of acceptors was observed. For a...
Contrary to previous results, a unique anti-correlation effect of the alkyl chain size on the photovoltaic performance of acceptors was observed. For a centrally-extended acceptor, replacing linear alkyl chains (-undecyl for CH-BBQ) on the thienothiophene unit with branched ones (2-butyloctyl for CH-BO) leads to a plunge in the power conversion efficiency of organic solar cells (18.12% 11.34% for binary devices), while the largely shortened ones (-heptyl for CH-HP) bring a surge in performance (18.74%/19.44% for binary/ternary devices). Compared with CH-BO, the more compact intermolecular packing of CH-HP facilitates carrier transport. The characterization of organic field effect transistors and carrier dynamics also echoes the above results. Molecular dynamics simulations indicate that the encounter of the branched alkyl chains and the extended central core hinders the effective interfacial interaction of polymer donors and acceptors, thus deteriorating the device performance. This work suggests that the conventional strategy for alkyl chain engineering of Y-series acceptors might need to be reconsidered in other molecular systems.
PubMed: 38946704
DOI: 10.1039/d4mh00699b -
Advanced Science (Weinheim,... Jul 2024Amphiphilic block copolymers are promising candidates for the fabrication of ultrafiltration membranes with an isoporous integral asymmetric structure. The membranes are...
Amphiphilic block copolymers are promising candidates for the fabrication of ultrafiltration membranes with an isoporous integral asymmetric structure. The membranes are typically fabricated by the combination of block copolymer self-assembly and the non-solvent-induced phase separation (SNIPS) process resulting in isoporous integral asymmetric membranes. Certainly, all these membranes lack thermal and chemical stability limiting the usage of such materials. Within this study, the fabrication of completely cross-linked isoporous integral asymmetric block copolymer membranes is demonstrated by UV cross-linking resulting in chemical and thermal stable ultrafiltration membranes. The UV cross-linking process of PVBCB-b-P4VP (poly(4-vinylbenzocyclobutene)-b-poly(4vinylpyridine)) block copolymer membranes in dependency of irradiation time, intensity, distance between membrane and UV source and the wavelength is investigated. Furthermore, it is shown that the penetration depths can be increased by soaking the membranes in wave-guiding solutions before UV cross-linking is carried out. Moreover, a completely new and easy cross-linking strategy is developed based on isorefractive solvents resulting in thermal and chemically stable membranes that are cross-linked through the whole membrane thickness. Finally, the new cross-linking strategy in isorefractive solutions is transferred to commercial PVDF and PAN-co-PVC polymer membranes paving the way for more stable and sustainable ultrafiltration membranes.
PubMed: 38946670
DOI: 10.1002/advs.202403288 -
Physiological Reports Jul 2024The present study aimed to investigate the effect of catechin-loaded Chitosan-Alginate nanoparticles (NPs) on cognitive function in an aluminum chloride (AlCl)-induced...
Oral administration of encapsulated catechin in chitosan-alginate nanoparticles improves cognitive function and neurodegeneration in an aluminum chloride-induced rat model of Alzheimer's disease.
The present study aimed to investigate the effect of catechin-loaded Chitosan-Alginate nanoparticles (NPs) on cognitive function in an aluminum chloride (AlCl)-induced rat model of Alzheimer's disease (AD). The Catechin-loaded Chitosan-Alginate nanocarriers were synthesized through ionotropic gelation (IG) method. Physio-chemical characterization was conducted with the Zetasizer Nano system, the scanning electron microscope, and the Fourier transform infrared spectroscopy. The experiments were performed over 21 days on six groups of male Wistar rats. The control group, AlCl treated group, Catechin group, nanocarrier group, treatment group 1 (AlCl + Catechin), and treatment group 2 (AlCl + nanocarrier). A behavioral study was done by the Morris water maze (MWM) test. In addition, the level of oxidative indices and acetylcholine esterase (AChE) activity was determined by standard procedures at the end of the study. AlCl induced a significant increase in AChE activity, along with a significant decrease in the level of Catalase (CAT) and total antioxidant capacity (TAC) in the hippocampus. Moreover, the significant effect of AlCl was observed on the behavioral parameters of the MWM test. Both forms of Catechin markedly improved AChE activity, oxidative biomarkers, spatial memory, and learning. The present study indicated that the administration of Catechin-loaded Chitosan-Alginate NPs is a beneficial therapeutic option against behavioral and chemical alteration of AD in male Wistar rats.
Topics: Animals; Catechin; Aluminum Chloride; Chitosan; Alginates; Male; Rats, Wistar; Alzheimer Disease; Rats; Nanoparticles; Administration, Oral; Cognition; Acetylcholinesterase; Maze Learning; Hippocampus; Disease Models, Animal; Antioxidants; Oxidative Stress; Drug Carriers
PubMed: 38946616
DOI: 10.14814/phy2.16095 -
Circulation. Cardiovascular... Jul 2024
PubMed: 38946556
DOI: 10.1161/CIRCINTERVENTIONS.124.014276 -
Misleading Pore Size Measurements in Gelatin and Alginate Hydrogels revealed by Confocal Microscopy.Tissue Engineering. Part C, Methods Jul 2024It is a well-documented phenomenon that the porous structure of hydrogels observed with vacuum-based imaging techniques is generated during the freezing and drying...
It is a well-documented phenomenon that the porous structure of hydrogels observed with vacuum-based imaging techniques is generated during the freezing and drying process employed prior to observation. Nevertheless, vacuum-based techniques, such as scanning electron microscopy (SEM), are still being commonly used to measure pore sizes in hydrogels, which is often not representative of the actual pore size in hydrated conditions. The frequent underestimation of the impact of freezing and drying on hydrogel structures could stem from a lack of cross-fertilization between materials science and biomedical or food science communities, or from the simplicity and visually appealing nature of SEM imaging which may lead to an overemphasis on its use. Our study provides a straightforward and impactful way of pinpointing this phenomenon exploiting two hydrogels ubiquitously applied in tissue engineering, including gelatin methacryloyl (GelMA) and alginate as proof-of-concept hydrogels. By comparing images of the samples in the native hydrated state, followed by freezing, freeze-drying and rehydration using SEM and confocal microscopy, we highlight discrepancies between hydrogel pore sizes in the hydrated versus the dry state. To conclude, our study offers recommendations for researchers seeking insight in hydrogel properties and emphasizes key factors that require careful control when using SEM as a characterization tool.
PubMed: 38946552
DOI: 10.1089/ten.TEC.2024.0117 -
Journal of Liposome Research Jul 2024Emtricitabine (FTC) a BCS class I drug, is used for HIV prevention. The high solubility of the drug is the leading cause of severe hepatotoxicity and lactic acidosis....
Emtricitabine (FTC) a BCS class I drug, is used for HIV prevention. The high solubility of the drug is the leading cause of severe hepatotoxicity and lactic acidosis. This research focuses on the use of modified pullulan for the preparation of polymeric liposomes of FTC. Modified pullulan was synthesized using cholesterol, and succinic anhydride in a controlled chemical environment. The formation of the polymer was established through analysis of spectra. Varying the drug-polymer ratio (1:1, 1:2, and 1:3), the drug-polymer composite was loaded in the vesicular system of soya phosphatidylcholine and cholesterol. Formulations were evaluated for drug entrapment, particle size, surface morphology, and and drug release. An study of the pure drug and the best formulation on mice was conducted for 28 days following daily oral administration to evaluate the effect on liver and hematological parameters. The best formulation was further subjected to cytotoxicity study on hepatic cell lines. Spectral analysis confirmed the formation of modified pullulan. All formulations showed high drug entrapment in the nanovesicles. and drug release profiles depicted a controlled release of the drug. Hematological parameters were found to be under control in the animals throughout the experimentation. A comparative histopathology study on the livers and cytotoxicity study on hepatic cell lines revealed the safety of the best formulation over the pure drug. Hence it can be concluded that polymeric liposomes of FTC can be a promising mode of delivery to overcome its limitations.
PubMed: 38946524
DOI: 10.1080/08982104.2024.2362352 -
Journal of Indian Prosthodontic Society Jul 2024Studies have not been done to evaluate the peri-implant stress exerted by materials(like PEEK and resin matrix ceramics) in different osseointegration conditions. To...
AIM
Studies have not been done to evaluate the peri-implant stress exerted by materials(like PEEK and resin matrix ceramics) in different osseointegration conditions. To investigate the effect of different occlusal materials on peri-implant stress distribution with different osseointegration condition using finite element analysis.
SETTINGS AND DESIGN
Eighteen different 3D FEA models of implant fixed with abutment were created involving 6 different occlusal materials (Heat cured temporary acrylic resin (PMMA), Bis-GMA, PEEK, Lithium disilicate, Resin matrix ceramics and translucent Zirconia) and different osseointegrated conditions (50%, 75%, 100%).
MATERIALS AND METHODS
Models were subjected to loading vertically and obliquely followed by evaluation of stress distribution.
STATISTICAL ANALYSIS USED
The results of the simulation obtained were analysed in terms of Von mises, maximum principal and minimal principal stresses using descriptive stastistics.
RESULTS
PMMA (40.14 MPa on vertical loading and 66 MPa on oblique loading) resulted in the highest stresses and lithium disilicate (24 MPa on vertical loading and 52.40 MPa on oblique loading) resulted in least stresses among all the crown materials. Upon oblique loading, von Mises stress increases except for translucent zirconia and lithium disilicate (52.444 MPa on 50%, 47.733 MPa on 75%, and 43.973 MPa on 100% osseointegration). Minimal principal stress values decreased with increase in osseointegration upon oblique loading for PMMA, BisGMA, and PEEK.
CONCLUSION
Translucent zirconia and lithium disilicate offer a better stress transmission. Minimal principal stress values of PEEK and BisGMA decreased with increasing osseointegration.
Topics: Finite Element Analysis; Osseointegration; Dental Materials; Dental Implants; Zirconium; Humans; Dental Porcelain; Ceramics; Materials Testing; Stress, Mechanical; Dental Stress Analysis; Polymethyl Methacrylate; Polymers
PubMed: 38946514
DOI: 10.4103/jips.jips_424_23 -
Journal of Indian Prosthodontic Society Jul 2024The aim of this study was to evaluate the effect of proanthocyanidin and C. sinensis-polyphenols on microtensile bonding properties of prepared teeth with resin-modified... (Comparative Study)
Comparative Study
Comparison of microtensile bond strength of prepared teeth treated with proanthocyanidin, Camellia sinensis - Polyphenols, and metal crowns luted with resin-modified glass ionomer cement: An in vitro study.
AIM
The aim of this study was to evaluate the effect of proanthocyanidin and C. sinensis-polyphenols on microtensile bonding properties of prepared teeth with resin-modified glass ionomer cement (GIC).
SETTING AND DESIGN
This was an in vitro study.
MATERIALS AND METHODS
Seventy-eight maxillary premolars were selected and mounted into auto-polymerizing acrylic resin blocks. The samples were prepared and metal crowns were fabricated. The samples were randomly divided into three groups. Samples under Group 1 were not treated with any of the extracts and followed conventional bonding protocol. Samples under Group 2 and Group 3 were treated with proanthocyanidin and C. sinensis-polyphenols, respectively. After dentin treatment, these samples were luted to metal crowns using resin-modified GIC. Universal testing machine was used to measure the load at which the crowns were debonded and microtensile bond strength in MPa was calculated.
STATISTICAL ANALYSIS
The results were statistically analyzed using one-way ANOVA and post hoc Tukey HSD.
RESULTS
Samples treated with C. sinensis polyphenols (Group 3) had maximum bond strength followed by Group 2, where the samples were treated with proanthocyanidin.
CONCLUSION
C. sinensis polyphenols due to their anti-proteolytic and antioxidant properties showed improved bond strength compared to proanthocyanidin, a cross-linking agent, followed by conventional bonding protocol.
Topics: Proanthocyanidins; Tensile Strength; Glass Ionomer Cements; Polyphenols; Humans; Crowns; Dental Bonding; Camellia sinensis; In Vitro Techniques; Resin Cements; Plant Extracts; Dental Stress Analysis
PubMed: 38946512
DOI: 10.4103/jips.jips_127_24 -
Journal of Indian Prosthodontic Society Jul 2024Occurrence of denture stomatitis and prosthesis breakage are common problems faced by elderly people wearing removable dentures. To overcome this, several attempts are...
AIM
Occurrence of denture stomatitis and prosthesis breakage are common problems faced by elderly people wearing removable dentures. To overcome this, several attempts are made to improve the denture material by addition of antimicrobials without compromising original properties. The aim of the study was to evaluate flexural strength and microhardness of self-cured polymethyl methacrylate (PMMA) denture base resin after addition of Vaccinium macrocarpon (commonly called as cranberry), extract as antimicrobial, at varying proportions.
STUDY SETTING AND DESIGN
Experimental in vitro study.
MATERIALS AND METHODS
Frozen cranberry fruits were subjected to extraction process in the presence of aqueous solvents. Lyophilized extract was added in proportions of 0, 0.5, 1.0, 1.5, and 2.0 dry wt/wt % into polymer of self-cure PMMA denture base resin. Based on cranberry inclusion, the study comprised one control (0%) and four test groups (0.5%-2%) with total of 100 samples. A three-point bending test for flexural strength was done for fifty study samples (n = 10). Surface of fractured samples was analyzed using a scanning electron microscope (SEM). Microhardness was determined using Vickers hardness test.
STATISTICAL ANALYSIS USED
One-way statistical ANOVA test was done to find the difference between groups, followed by Tukey's post hoc test for multiple pairwise comparison.
RESULTS
Flexural strength ranged from 66.80 to 69.28 MPa, and a statistically insignificant difference was observed between groups (P > 0.05). SEM evaluation showed uniformly dispersed strands of cranberry extract in PMMA matrix. With higher concentration, less voids were seen. Vickers microhardness value significantly decreased from 15.96 in the control group to 14.57 with 2% cranberry addition (P < 0.05).
CONCLUSION
Incorporation of cranberry extract into self-cure PMMA denture base resin, up to 2 dry wt %, did not decline the flexural strength. However, there was a significant decrease in Vickers microhardness values when compared against the control group (0% cranberry inclusion).
Topics: Polymethyl Methacrylate; Hardness; Flexural Strength; Vaccinium macrocarpon; Plant Extracts; Materials Testing; Humans; Denture Bases; Dental Materials; Anti-Infective Agents; In Vitro Techniques
PubMed: 38946510
DOI: 10.4103/jips.jips_25_24