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Molecules (Basel, Switzerland) Aug 2022A sensitive and selective fluorescence-detection platform based on carbon quantum dots (CQDs) was designed and developed for the determination of methotrexate (MTX), for...
OBJECTIVE
A sensitive and selective fluorescence-detection platform based on carbon quantum dots (CQDs) was designed and developed for the determination of methotrexate (MTX), for the purpose of minimizing the possible toxic threat of MTX in clinics.
METHODS
The approach was prepared for the first time by a simple, hydrothermal method, making the synthesis and modification processes realized in one step using polyethyleneimine (PEI), and the proposed PEI-CQDs were obtained with high fluorescence quantum yield (38%).
RESULTS
MTX was found highly responsive and effective in quenching the fluorescence of the PEI-CQDs, due to a suggested fluorescence resonance energy transfer mechanism or inner-filter effect. The linear range of MTX was between 1 and 600 μmol/L under optimum conditions, with a detection limit (LOD) as low as 0.33 μmol/L. Furthermore, the fluorescent method was established for the MTX assay, and satisfactory results were acquired in real-sample determination. The average labeled quantity was 98.2%, and the average added standard recovery was 100.9%.
CONCLUSIONS
The proposed PEI-CQDs showed a remarkable potential for broad applications in biological molecule determination and environmental analysis.
Topics: Carbon; Fluorescent Dyes; Limit of Detection; Methotrexate; Polyethyleneimine; Polyvinyls; Quantum Dots; Spectrometry, Fluorescence
PubMed: 36014493
DOI: 10.3390/molecules27165254 -
BMC Oral Health Jul 2023Polyvinyl ether siloxane (PVES) possesses ideal characteristics for making precise and accurate dental impressions. PVES dimensional stability owes to its better... (Meta-Analysis)
Meta-Analysis
BACKGROUND AND OBJECTIVES
Polyvinyl ether siloxane (PVES) possesses ideal characteristics for making precise and accurate dental impressions. PVES dimensional stability owes to its better polymeric properties derived from its parent materials poly ethers and polyvinyl siloxanes. As recommended use of chemical disinfecting agents is getting more popular, there is a growing concern associated with the effect of disinfectants on PVES dimensional stability. This study was aimed to understand the PVES behavior when subjected to chemical disinfectants.
MATERIALS AND METHODOLOGY
The data was collected from research studies retrieved from Google Scholar, Scopus, and PubMed using MeSH terms of keywords "vinyl polyether siloxane AND Disinfection" or (Vinyl polyether siloxane OR polyvinyl siloxane ether OR PVES) AND (disinfectant OR disinfection)" without any restriction to publication date. The PRISMA (Preferred Reporting Items for Systemic Review and Meta-Analysis) directions were observed during the data collection, screening of studies, and meta-analysis. The primary data were retrieved, and batch exported from databases using Harzing's Publish or Perish software; primary analysis was performed in Microsoft Excel, while statistical analysis for effect size, two-tailed p-values, and heterogeneity among studies was performed using Meta Essentials. The effect size was calculated using Hedge's g values at the 95% confidence level using the random-effects model. Heterogeneity among studies was measured using the Cochrane Q and I.
RESULTS AND CONCLUSION
Dental impressions made from the PVES elastomeric impression materials showed no significant changes in dimensional stability. Immersion in the chemical disinfectant for 10 min was associated with clinically irrelevant changes in the dimensions of the PVES impressions. Disinfection with sodium hypochlorite was associated with clinically significant changes in dimensions, with a two-tailed p-value of 0.049. Disinfection with 2-2.5% glutaraldehyde solution was not associated with any significant dimensional variability.
Topics: Humans; Disinfectants; Disinfection; Ether; Ethers; Ethyl Ethers; Polyvinyls; Siloxanes
PubMed: 37430254
DOI: 10.1186/s12903-023-03168-8 -
Molecules (Basel, Switzerland) Feb 2023Presently, the rising concerns about the fossil fuel crisis and ecological deterioration have greatly affected the world economy and hence have attracted attention to... (Review)
Review
Presently, the rising concerns about the fossil fuel crisis and ecological deterioration have greatly affected the world economy and hence have attracted attention to the utilization of renewable energies. Among the renewable energy being developed, supercapacitors hold great promise in broad applications such as electric vehicles. Presently, the main challenge facing supercapacitors is the amount of energy stored. This, however, does not satisfy the increasing demand for higher energy storage devices, and therefore, intensive research is being undertaken to overcome the challenges of low energy density. The purpose of this review is to report on solid polymer electrolytes (SPEs) based on polyvinyl alcohol (PVA). The review discussed the PVA as a host polymer in SPEs followed by a discussion on the influence of conducting salts. The formation of SPEs as well as the ion transport mechanism in PVA SPEs were discussed. The application and development of PVA-based polymer electrolytes on supercapacitors and other energy storage devices were elucidated. The fundamentals of electrochemical characterization for analyzing the mechanism of supercapacitor applications, such as EIS, LSV and dielectric constant, are highlighted. Similarly, thermodynamic transport models of ions and their mechanism about temperature based on Arrhenius and Vogel-Tammann-Fulcher (VTF) are analyzed. Methods for enhancing the electrochemical performance of PVA-based SPEs were reported. Likely challenges facing the current electrolytes are well discussed. Finally, research directions to overcome the present challenges in producing SPEs are proposed. Therefore, this review is expected to be source material for other researchers concerned with the development of PVA-based SPE material.
Topics: Polyvinyl Alcohol; Polymers; Ethanol; Electrolytes; Salts
PubMed: 36838770
DOI: 10.3390/molecules28041781 -
Australian Dental Journal Dec 1998Polyvinyl siloxane impression materials have applications in a variety of indirect procedures in prosthodontics and restorative dentistry. Favourable handling... (Review)
Review
Polyvinyl siloxane impression materials have applications in a variety of indirect procedures in prosthodontics and restorative dentistry. Favourable handling properties, good patient acceptance and excellent physical properties have resulted in their popularity in today's practice. In this review, the chemistry and important physical properties of polyvinyl siloxanes are summarized, and recent clinical questions of improved hydrophilics, tray adhesives, disinfection, and glove-induced polymerization inhibition are addressed.
Topics: Adhesives; Chemical Phenomena; Chemistry, Physical; Dental Impression Materials; Dental Impression Technique; Dental Restoration, Permanent; Dentures; Disinfection; Humans; Latex; Polymers; Polyvinyls; Siloxanes; Surface Properties; Water
PubMed: 9973714
DOI: 10.1111/j.1834-7819.1998.tb00204.x -
Molecules (Basel, Switzerland) May 2020In nanoimprint lithography (NIL), a pattern is created by mechanical deformation of an imprint resist via embossing with a stamp, where the adhesion behavior during the...
In nanoimprint lithography (NIL), a pattern is created by mechanical deformation of an imprint resist via embossing with a stamp, where the adhesion behavior during the filling of the imprint stamp and its subsequent detachment may impose some practical challenges. Here we explored thermal and reverse NIL patterning of polyvinylferrocene and vinylferrocene-methyl methacrylate copolymers to prepare complex non-spherical objects and patterns. While neat polyvinylferrocene was found to be unsuitable for NIL, freshly-prepared vinylferrocene-methyl methacrylate copolymers, for which identity and purity were established, have been structured into 3D-micro/nano-patterns using NIL. The cross-, square-, and circle-shaped columnar structures form a 3 × 3 mm arrangement with periodicity of 3 µm, 1 µm, 542 nm, and 506 nm. According to our findings, vinylferrocene-methyl methacrylate copolymers can be imprinted without further additives in NIL processes, which opens the way for redox-responsive 3D-nano/micro-objects and patterns via NIL to be explored in the future.
Topics: Ferrous Compounds; Methylmethacrylate; Molecular Imprinting; Nanocomposites; Polymers; Polyvinyls; Surface Properties; Vinyl Compounds
PubMed: 32456151
DOI: 10.3390/molecules25102438 -
Molecules (Basel, Switzerland) Sep 2022The development of targeted therapies for wound repair is knowing a growing interest due to the increasing aging of the population and the incidence of chronic...
The development of targeted therapies for wound repair is knowing a growing interest due to the increasing aging of the population and the incidence of chronic pathologies, mainly pressure ulcers. Among molecules recruiting cell populations and promoting the formation of new vital tissue, sodium mesoglycan (MSG) has been proven to be effective in wound healing. In this work, MSG impregnation of polymer matrices has been attempted by a supercritical carbon dioxide-based process. Polymeric matrices are composed of polycaprolactone blends, where water-soluble polymers, polyethylene glycol, polyvinyl pyrrolidone, gelatin, and thermoplastic starch, have been employed to modulate the MSG release, making the devices potentially suitable for topical administrations. Two different techniques have been used to obtain the films: the first one is compression molding, producing compact and continuous structures, and the second one is electrospinning, producing membrane-like designs. A higher amount of MSG can be loaded into the polymeric matrix in the membrane-like structures since, in these films, the impregnation process is faster than in the case of compression molded films, where the carbon dioxide has firstly diffused and then released the active molecule. The type of water-soluble polymer influences the drug release rate: the blend polycaprolactone-gelatin gives a prolonged release potentially suitable for topical administration.
Topics: Carbon Dioxide; Gelatin; Glycosaminoglycans; Polyesters; Polyethylene Glycols; Polymers; Polyvinyls; Povidone; Sodium; Starch; Water
PubMed: 36144536
DOI: 10.3390/molecules27185800 -
Drug Delivery and Translational Research Aug 2022The issue of poor aqueous solubility is often a great hitch in the development of liquid dosage forms for those drugs that the Biopharmaceutics Classification System...
The issue of poor aqueous solubility is often a great hitch in the development of liquid dosage forms for those drugs that the Biopharmaceutics Classification System (BCS) includes in classes II and IV. Among the possible technological solutions, inclusion of the drug molecule within polymeric micelles, and particularly nanomicelles, has been proposed in the last years as a valid strategy. Our attention has been recently attracted by Soluplus, an amphiphilic polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer able to form small and stable nanomicelles. The aim of this study was to characterize Soluplus nanomicelles to enhance the apparent solubility of three model APIs, categorized in BCS class II: ibuprofen (IBU), idebenone (IDE), and miconazole (MIC). Drug-loaded Soluplus micelles with a mean size around 60-70 nm were prepared by two methods (direct dissolution or film hydration method). The prepared nanosystems were characterized in terms of mean particle size and Zeta potential, physical stability, drug solubility, and in vitro drug release. The solubility of the tested APIs was shown to increase linearly with the concentration of graft copolymer. Soluplus can be easily submitted to membrane filtration (0.2 µm PES or PTFE membranes), showing the potential to be sterilized by this method. Freeze-drying enabled to obtain powder materials that, upon reconstitution with water, maintained the initial micelle size. Finally, viscosity studies indicated that these nanomicelles have potential applications where a bioadhesive material is advantageous, such as in topical ocular administration.
Topics: Biopharmaceutics; Micelles; Polyethylene Glycols; Polymers; Polyvinyls; Solubility
PubMed: 35604634
DOI: 10.1007/s13346-022-01182-x -
Proceedings of the Royal Society of... Oct 1970
Topics: Humans; Polyvinyls; Protective Clothing; Radiation Protection; Ventilators, Mechanical
PubMed: 5274210
DOI: No ID Found -
BMC Oral Health Sep 2022This study aimed to compare the dimensional accuracy, hydrophilicity and detail reproduction of the hybrid vinylsiloxnether with polyether and polyvinylsiloxane parent...
BACKGROUND
This study aimed to compare the dimensional accuracy, hydrophilicity and detail reproduction of the hybrid vinylsiloxnether with polyether and polyvinylsiloxane parent elastomers using modified digital techniques and software. This was done in an attempt to aid in solving the conflict between the different studies published by competitive manufacturers using different common manual approaches.
METHODS
A polyether, polyvinylsiloxanes and vinyl polyether silicone hybrid elastomeric impression materials were used in the study. Dimensional accuracy was evaluated through taking impressions of a metallic mold with four posts representing a partially edentulous maxillary arch, that were then poured with stone. Accuracy was calculated from the mean of measurements taken between fixed points on the casts using digital single-lens reflex camera to produce high-resolution digital pictures for all the casts with magnification up to 35×. Hydrophilicity was assessed by contact angle measurements using AutoCAD software. The detail reproduction was measured under dry conditions according to ANSI/ADA Standard No. 19 and under wet conditions as per ISO 4823. A metallic mold was used with three V shaped grooves of 20, 50, and 75 µm width. Specimens were prepared and examination was made immediately after setting using digital images at a magnification of 16×.
RESULTS
The hybrid impression (0.035 mm) material showed significantly higher dimensional accuracy compared to the polyether (0.051 mm) but was not as accurate as the polyvinyl siloxane impression material (0.024 mm). The contact angles of the hybrid material before and after setting was significantly lower than the parent materials. With regard to the detail reproduction, the three tested materials were able precisely to reproduce the three grooves of the mold under dry conditions. Whereas, under wet conditions, the hybrid material showed higher prevalence of well-defined reproduction of details same as polyether but higher than polyvinylsiloxane that showed prevalence of details with loss of sharpness and continuity.
CONCLUSIONS
The digital technique used could be a more reliable and an easier method for assessment of impression materials properties. The hybridization of polyvinyl siloxane and polyether yielded a promising material that combines the good merits of both materials and overcomes some of their drawbacks.
Topics: Dental Impression Materials; Dental Impression Technique; Elastomers; Humans; Materials Testing; Polyvinyls; Silicones; Siloxanes; Surface Properties
PubMed: 36064393
DOI: 10.1186/s12903-022-02419-4 -
General Thoracic and Cardiovascular... May 2022The increasing use of total arch replacement and frozen elephant trunk (FET) is expected to lead to an increase in the prevalence of graft infections requiring...
The increasing use of total arch replacement and frozen elephant trunk (FET) is expected to lead to an increase in the prevalence of graft infections requiring replacement involving an FET, which is generally a more invasive procedure than the initial surgery. Herein, we describe a novel method for FET removal using a polyvinyl tube as the storage device. The procedure is completed using the same median sternotomy approach as the initial surgery. We report on the outcomes for six patients. Our procedure is simple to perform and safe and caused no injury to the aorta in our case series.
Topics: Aorta; Aorta, Thoracic; Aortic Aneurysm, Thoracic; Blood Vessel Prosthesis Implantation; Humans; Polyvinyls; Retrospective Studies
PubMed: 35246777
DOI: 10.1007/s11748-022-01790-x