-
Brazilian Oral Research Oct 2016The objective of this study was to evaluate the marginal and internal fit of zirconia copings obtained with different digital scanning methods. A human mandibular first...
The objective of this study was to evaluate the marginal and internal fit of zirconia copings obtained with different digital scanning methods. A human mandibular first molar was set in a typodont with its adjacent and antagonist teeth and prepared for an all-ceramic crown. Digital impressions were made using an intraoral scanner (3Shape). Polyvinyl siloxane impressions and Type IV gypsum models were also obtained and scanned with a benchtop laboratory scanner (3Shape D700). Ten zirconia copings were fabricated for each group using CAD-CAM technology. The marginal and internal fit of the zirconia copings was assessed by the silicone replica technique. Four sections of each replica were obtained, and each section was evaluated at four points: marginal gap (MG), axial wall (AW), axio-occlusal edge (AO) and centro-occlusal wall (CO), using an image analyzing software. The data were submitted to one-way ANOVA and Tukey's test (α = 0.05). They showed statistically significant differences for MG, AO and CO. Regarding MG, intraoral scanning showed lower gap values, whereas gypsum model scanning showed higher gap values. Regarding AO and CO, intraoral digital scanning showed lower gap values. Polyvinyl siloxane impression scanning and gypsum model scanning showed higher gap values and were statistically similar. It can be concluded that intraoral digital scanning provided a lower mean gap value, in comparison with conventional impressions and gypsum casts scanned with a standard benchtop laboratory scanner.
Topics: Analysis of Variance; Calcium Sulfate; Computer-Aided Design; Dental Casting Technique; Dental Impression Materials; Dental Impression Technique; Dental Marginal Adaptation; Dental Prosthesis Design; Humans; Image Processing, Computer-Assisted; Materials Testing; Polyvinyls; Reference Values; Reproducibility of Results; Siloxanes; Zirconium
PubMed: 27737366
DOI: 10.1590/1807-3107BOR-2016.vol30.0113 -
Biomacromolecules Sep 2015Heparin is a highly sulfated polysaccharide and is useful because of its diverse biological functions. However, because of batch-to-batch variability and other factors,...
Heparin is a highly sulfated polysaccharide and is useful because of its diverse biological functions. However, because of batch-to-batch variability and other factors, there is significant interest in preparing biomimetics of heparin. To identify polymeric heparin mimetics, a cell-based screening assay was developed in cells that express fibroblast growth factor receptors (FGFRs) but not heparan sulfate proteoglycans. Various sulfated and sulfonated polymers were screened, and poly(vinyl sulfonate) (pVS) was identified as the strongest heparin-mimicking polymer in its ability to enhance binding of basic fibroblast growth factor (bFGF) to FGFR. The results were confirmed by an ELISA-based receptor-binding assay. Different molecular weights of pVS polymer were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The polymers were able to facilitate dimerization of FGFRs leading to cell proliferation in FGFR-expressing cells, and no size dependence was observed. The data showed that pVS is comparable to heparin in these assays. In addition, pVS was not cytotoxic to fibroblast cells up to at least 1 mg/mL. Together this data indicates that pVS should be explored further as a replacement for heparin.
Topics: Biomimetic Materials; Cell Proliferation; Cells, Cultured; Fibroblast Growth Factor 2; Heparin; Humans; Polyvinyls; Sulfonic Acids
PubMed: 26212474
DOI: 10.1021/acs.biomac.5b00557 -
Journal of Visualized Experiments : JoVE Aug 2012Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime. Lithium ion batteries have...
Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime. Lithium ion batteries have also been considered to be used in electric and hybrid vehicles or even electrical grid stabilization systems. All these applications simulate a dramatic increase in the research and development of battery materials, including new materials, doping, nanostructuring, coatings or surface modifications and novel binders. Consequently, an increasing number of physicists, chemists and materials scientists have recently ventured into this area. Coin cells are widely used in research laboratories to test new battery materials; even for the research and development that target large-scale and high-power applications, small coin cells are often used to test the capacities and rate capabilities of new materials in the initial stage. In 2010, we started a National Science Foundation (NSF) sponsored research project to investigate the surface adsorption and disordering in battery materials (grant no. DMR-1006515). In the initial stage of this project, we have struggled to learn the techniques of assembling and testing coin cells, which cannot be achieved without numerous help of other researchers in other universities (through frequent calls, email exchanges and two site visits). Thus, we feel that it is beneficial to document, by both text and video, a protocol of assembling and testing a coin cell, which will help other new researchers in this field. This effort represents the "Broader Impact" activities of our NSF project, and it will also help to educate and inspire students. In this video article, we document a protocol to assemble a CR2032 coin cell with a LiCoO2 working electrode, a Li counter electrode, and (the mostly commonly used) polyvinylidene fluoride (PVDF) binder. To ensure new learners to readily repeat the protocol, we keep the protocol as specific and explicit as we can. However, it is important to note that in specific research and development work, many parameters adopted here can be varied. First, one can make coin cells of different sizes and test the working electrode against a counter electrode other than Li. Second, the amounts of C black and binder added into the working electrodes are often varied to suit the particular purpose of research; for example, large amounts of C black or even inert powder were added to the working electrode to test the "intrinsic" performance of cathode materials. Third, better binders (other than PVDF) have also developed and used. Finally, other types of electrolytes (instead of LiPF6) can also be used; in fact, certain high-voltage electrode materials will require the uses of special electrolytes.
Topics: Cations, Monovalent; Cobalt; Electric Power Supplies; Electrodes; Oxides; Polyvinyls
PubMed: 22895280
DOI: 10.3791/4104 -
International Journal of Molecular... Dec 2021The predominant impediments to cutaneous wound regeneration are hemorrhage and bacterial infections that lead to extensive inflammation with lethal impact. We thus...
The predominant impediments to cutaneous wound regeneration are hemorrhage and bacterial infections that lead to extensive inflammation with lethal impact. We thus developed a series of composite sponges based on polyvinyl alcohol (PVA) inspired by marjoram essential oil and kaolin (PVA/marjoram/kaolin), adopting a freeze-thaw method to treat irregular wounds by thwarting lethal bleeding and microbial infections. Microstructure analyses manifested three-dimensional interconnected porous structures for PVA/marjoram/kaolin. Additionally, upon increasing marjoram and kaolin concentrations, the pore diameters of the sponges significantly increased, recording a maximum of 34 ± 5.8 µm for PVA-M0.5-K0.1. Moreover, the porosity and degradation properties of PVA/marjoram/kaolin sponges were markedly enhanced compared with the PVA sponge with high swelling capacity. Furthermore, the PVA/marjoram/kaolin sponges exerted exceptional antibacterial performance against and , along with remarkable antioxidant properties. Moreover, PVA/marjoram/kaolin sponges demonstrated significant thrombogenicity, developing high thrombus mass and hemocompatibility, in addition to their remarkable safety toward fibroblast cells. Notably, this is the first study to our knowledge investigating the effectiveness of marjoram in a polymeric carrier for prospective functioning as a wound dressing. Collectively, the findings suggest the prospective usage of the PVA-M0.5-K0.1 sponge in wound healing for hemorrhage and bacterial infection control.
Topics: Animals; Anti-Bacterial Agents; Antioxidants; Bandages; Hemostatics; Humans; Kaolin; Materials Testing; Mice; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; NIH 3T3 Cells; Origanum; Plant Extracts; Polyvinyl Alcohol; Polyvinyls; Spectroscopy, Fourier Transform Infrared; Thermogravimetry
PubMed: 34884855
DOI: 10.3390/ijms222313050 -
International Journal of Environmental... Jun 2020Due to the high prevalence of periodontitis, dentists have to face a larger group of patients with periodontally compromised dentitions (PCDs) characterized by... (Clinical Trial)
Clinical Trial
Due to the high prevalence of periodontitis, dentists have to face a larger group of patients with periodontally compromised dentitions (PCDs) characterized by pathologic tooth migration and malocclusion. Impression taking in these patients is challenging due to several undercuts and extensive interdental areas (IAs). The aim of this clinical trial was to analyze the ability of analog and digital impression techniques to display the IAs in PCDs. The upper and the lower jaws of 30 patients ( = 60, age: 48-87 years) were investigated with one conventional impression (CVI) using polyvinyl siloxane and four digital impressions with intraoral scanners (IOSs), namely True Definition (TRU), Primescan (PRI), CS 3600 (CAR), and TRIOS 3 (TIO). The gypsum models of the CVIs were digitalized using a laboratory scanner. Subsequently, the percentage of the displayed IAs in relation to the absolute IAs was calculated for the five impression techniques in a three-dimensional measuring software. Significant differences were observed among the impression techniques (except between PRI and CAR, -value < 0.05). TRU displayed the highest percentage of IAs, followed by PRI, CAR, TIO, and CVI. The results indicated that the IOSs are superior to CVI regarding the ability to display the IAs in PCDs.
Topics: Aged; Aged, 80 and over; Calcium Sulfate; Computer-Aided Design; Dental Impression Technique; Humans; Imaging, Three-Dimensional; Middle Aged; Periodontitis; Polyvinyls; Software
PubMed: 32630132
DOI: 10.3390/ijerph17134725 -
Sensors (Basel, Switzerland) Jun 2021The effect of a self-pulsing non-equilibrium plasma discharge on piezoelectric PVDF nanofiber membrane was investigated. The plasma discharge was generated in air with a...
The effect of a self-pulsing non-equilibrium plasma discharge on piezoelectric PVDF nanofiber membrane was investigated. The plasma discharge was generated in air with a DC power source, with a discharge current of 0.012 mA, a nominal interelectrode separation of 1 mm, and discharge voltage of ~970 V. In a continuous fabrication process, the electrospinning method was used to generate thin nanofiber membrane with a flow rate of 0.7-1 mL h and 25-27 kV voltage to obtain the nanofiber with high sensitivity and a higher degree of alignment and uniformity over a larger area. Plasma treatment was applied on both single layer and multi-layer (three layers) nanomembranes. In addition, simultaneously, the nanofiber membranes were heat-treated at a glass transition temperature (80-120 °C) and then underwent plasma treatment. Fourier-transform infrared (FTIR) spectroscopy showed that the area under the curve at 840 and 1272 cm (β phase) increased due to the application of plasma and differential scanning calorimeter (DSC) indicated an increase in the degree of crystallinity. Finally, PVDF sensors were fabricated from the nanofibers and their piezoelectric properties were characterized. The results suggested that compared to the pristine samples the piezoelectric properties in the plasma and plasma-heat-treated sensors were enhanced by 70% and 85% respectively.
Topics: Nanofibers; Polyvinyls; Spectroscopy, Fourier Transform Infrared; Temperature
PubMed: 34207088
DOI: 10.3390/s21124179 -
International Journal of Molecular... Sep 2019The interests of developing antimicrobial biomaterials based on silk sericin from cocoon, have been shooting up in the last decades. Sericin is a valuable natural...
The interests of developing antimicrobial biomaterials based on silk sericin from cocoon, have been shooting up in the last decades. Sericin is a valuable natural protein owing to its hydrophilicity, biodegradability, and biocompatibility. Here, we fabricated a sponge with antibacterial capacities for potential wound dressing application. By co-blending of sericin, polyvinyl alcohol (PVA) and zinc oxide nanoparticles (ZnONPs), the ZnONPs-sericin/PVA composite sponge (ZnONPs-SP) was successfully prepared after freeze-drying. Scanning electron microscopy showed the porous structure of ZnONPs-SP. Energy dispersive spectroscopy indicated the existence of Zn in the sponge. X-ray diffractometry revealed the hexagonal wurtzite structure of ZnONPs. Fourier transform infrared spectroscopy showed the biologic coupling of ZnONPs and sericin resulted in a decrease of α-helix and random coil contents, and an increase of β-sheet structure in the sponge. The swelling experiment suggested ZnONPs-SP has high porosity, good hydrophilicity, and water absorption capability. The plate bacterial colony counting coupled with growth curve assays demonstrated that the composite sponge has an efficiently bacteriostatic effect against and , respectively. Furthermore, the cell compatibility analysis suggested the composite sponge has excellent cytocompatibility on NIH3T3 cells. In all, ZnONPs-SP composite sponge has significant potentials in biomaterials such as wound dressing and tissue engineering.
Topics: Animals; Anti-Bacterial Agents; Bombyx; Cell Survival; Metal Nanoparticles; Mice; Microbial Sensitivity Tests; NIH 3T3 Cells; Polyvinyls; Porosity; Sericins; Spectroscopy, Fourier Transform Infrared; X-Ray Diffraction; Zinc Oxide
PubMed: 31569598
DOI: 10.3390/ijms20194796 -
Nigerian Journal of Clinical Practice Sep 2022To compare the effects of disinfectants on surface roughness of the conventional impression materials following chemical disinfection procedures.
BACKGROUND TO AIM
To compare the effects of disinfectants on surface roughness of the conventional impression materials following chemical disinfection procedures.
MATERIALS AND METHODS
Equal numbers (65 for each impression material) of disc-shaped (15 × 3 mm) samples (Total n = 195) were fabricated from polyvinyl siloxane (Zhermack Elite), polyether (3M Impregum Penta Soft), and vinyl siloxane ether (Kettenbach Identium Lightbody) impression materials. Each impression material group was divided into five subgroups including one control group (n = 13). Impression material samples were immersed in CaviCide for 3 min, Zeta 7 solution for 10 min, and 5.25% sodium hypochlorite solution for 3 and 10 min. Surface roughness (Ra) was measured using a profilometer (Mitutoyo-SJ 410, Mitutoyo Corp.). The study data were analyzed statistically.
RESULTS
A statistically significant difference was found among impression materials and disinfectants in terms of surface roughness (P < 0.05). Polyvinyl siloxane material showed a lower Ra value compared to Polyether and VSE materials; while polyether material showed a significantly lower Ra value compared to VSE material. Ra values of the control group were significantly lower than the disinfectant group immersed in 5.25% NaOCl solution for 10 min.
CONCLUSION
Among all impression materials, polyvinyl siloxane showed the least surface roughness following disinfection procedures. Impression disinfectants that are specially designed for disinfecting dental impressions resulted in less surface roughness in all impression materials. With this study, it was aimed to obtain a smooth and clear model for the production of correct and compatible prostheses in the laboratory while at the same time purifying the impressions from microorganisms.
Topics: Dental Impression Materials; Disinfectants; Disinfection; Ethers; Humans; Materials Testing; Polyvinyls; Siloxanes; Sodium Hypochlorite; Surface Properties
PubMed: 36149208
DOI: 10.4103/njcp.njcp_1920_21 -
International Journal of Molecular... Mar 2023Polyisocyanopeptide (PIC) hydrogels are proposed as promising wound dressings. These gels are thermo-sensitive, allow application as a cold liquid, and rely on gelation...
Polyisocyanopeptide (PIC) hydrogels are proposed as promising wound dressings. These gels are thermo-sensitive, allow application as a cold liquid, and rely on gelation through body heat. It is supposed that the gel can be easily removed by reversing the gelation and washing it away with a cold irrigation solution. The impact on wound healing of the regular application and removal of PIC dressings is compared to a single application of PIC and the clinically used Tegaderm™ in murine splinted full-thickness wounds for up to 14 days. SPECT/CT analysis of In-labelled PIC gels showed that, on average, 58% of the PIC gel could be washed out of the wounds with the employed method, which is, however, heavily influenced by personal technique. Evaluation with photography and (immuno-)histology showed that wounds in which PIC dressings were regularly removed and replaced were smaller at 14 days post-injury but performed on par with the control treatment. Moreover, the encapsulation of PIC in wound tissue was less severe and occurred less often when PIC was regularly refreshed. In addition, no morphological damage related to the removal procedure was observed. Thus, PIC gels are atraumatic and perform similarly to currently employed wound dressing materials, offering possible future benefits for both clinicians and patients.
Topics: Humans; Mice; Animals; Hydrogels; Wound Healing; Bandages; Polyvinyl Alcohol; Povidone
PubMed: 36982201
DOI: 10.3390/ijms24065127 -
Particle and Fibre Toxicology Oct 2021Silver nanoparticles (AgNPs) are widely used in biomedicine due to their strong antimicrobial, antifungal, and antiviral activities. Concerns about their possible...
BACKGROUND
Silver nanoparticles (AgNPs) are widely used in biomedicine due to their strong antimicrobial, antifungal, and antiviral activities. Concerns about their possible negative impacts on human and environmental health directed many researchers towards the assessment of the safety and toxicity of AgNPs in both in vitro and in vivo settings. A growing body of scientific information confirms that the biodistribution of AgNPs and their toxic effects vary depending on the particle size, coating, and dose as well as on the route of administration and duration of exposure. This study aimed to clarify the sex-related differences in the outcomes of oral 28 days repeated dose exposure to AgNPs.
METHODS
Wistar rats of both sexes were gavaged daily using low doses (0.1 and 1 mg Ag/kg b.w.) of polyvinylpyrrolidone (PVP)-coated small-sized (10 nm) AgNPs. After exposure, blood and organs of all rats were analysed through biodistribution and accumulation of Ag, whereas the state of the liver and kidneys was evaluated by the levels of reactive oxygen species (ROS) and glutathione (GSH), catalase (CAT) activity, superoxide dismutase (SOD) and glutathione peroxidase (GPx), expression of metallothionein (Mt) genes and levels of Mt proteins.
RESULTS
In all animals, changes in oxidative stress markers and blood parameters were observed indicating the toxicity of AgNPs applied orally even at low doses. Sex-related differences were noticed in all assessed parameters. While female rats eliminated AgNPs from the liver and kidneys more efficiently than males when treated with low doses, the opposite was observed for animals treated with higher doses of AgNPs. Female Wistar rats exposed to 1 mg PVP-coated AgNPs/kg b.w. accumulated two to three times more silver in the blood, liver, kidney and hearth than males, while the accumulation in most organs of digestive tract was more than ten times higher compared to males. Oxidative stress responses in the organs of males, except the liver of males treated with high doses, were less intense than in the organs of females. However, both Mt genes and Mt protein expression were significantly reduced after treatment in the liver and kidneys of males, while they remained unchanged in females.
CONCLUSIONS
Observed toxicity effects of AgNPs in Wistar rats revealed sex-related differences in response to an oral 28 days repeated exposure.
Topics: Animals; Female; Male; Metal Nanoparticles; Polyvinyls; Povidone; Rats; Rats, Wistar; Silver; Tissue Distribution
PubMed: 34663357
DOI: 10.1186/s12989-021-00425-y