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The FEBS Journal Oct 2011In the 1990s, a technique was developed to transfer proteins from electrophoresis gels onto poly(vinylidene difluoride) (PVDF) membranes, digest the proteins on the... (Review)
Review
In the 1990s, a technique was developed to transfer proteins from electrophoresis gels onto poly(vinylidene difluoride) (PVDF) membranes, digest the proteins on the membranes with proteases such as trypsin and analyze the resulting peptides on the membranes directly by mass spectrometry to identify the proteins. This technique, based on gel electrophoresis, is particularly useful for analyzing protein isoforms, splicing variants and post-translationally modified proteins. Previously, the low ionization efficiency of peptides immobilized on the membranes often rendered this technique useless. However, this technique has been improved by the use of PVDF membranes with a small pore size, which has enabled highly efficient and effective electroblotting and mass spectrometric analyses. Here, the advantage of this technique is discussed.
Topics: Combinatorial Chemistry Techniques; Electrophoresis, Polyacrylamide Gel; Mass Spectrometry; Peptides; Polyvinyls; Porosity; Proteins
PubMed: 21848805
DOI: 10.1111/j.1742-4658.2011.08303.x -
Environmental Health Perspectives Oct 1981Poly(vinyl chloride) resins are produced by four basic processes: suspension, emulsion, bulk and solution polymerization. PVC suspensions resins are usually relatively...
Poly(vinyl chloride) resins are produced by four basic processes: suspension, emulsion, bulk and solution polymerization. PVC suspensions resins are usually relatively dust-free and granular with varying degrees of particle porosity. PVC emulsion resins are small particle powders containing very little free monomer. Bulk PVC resins are similar to suspension PVC resins, though the particles tend to be more porous. Solution PVC resins are smaller in particle size than suspension PVC with high porosity particles containing essentially no free monomer. The variety of PVC resin products does not lend itself to broad generalizations concerning health hazards. In studying occupational hazards the particular PVC process and the product must be considered and identified in the study.
Topics: Chemical Industry; Humans; Particle Size; Polyvinyl Chloride; Polyvinyls; Risk; Vinyl Chloride
PubMed: 7333230
DOI: 10.1289/ehp.8141123 -
Scientific Reports Feb 2022Clinical use of human pluripotent stem cells (hPSCs) is hampered by the technical limitations of their expansion. Here, we developed a chemically synthetic culture...
Clinical use of human pluripotent stem cells (hPSCs) is hampered by the technical limitations of their expansion. Here, we developed a chemically synthetic culture substrate for human pluripotent stem cell attachment and maintenance. The substrate comprises a hydrophobic polyvinyl butyral-based polymer (PVB) and a short peptide that enables easy and uniform coating of various types of cell culture ware. The coated ware exhibited thermotolerance, underwater stability and could be stored at room temperature. The substrate supported hPSC expansion in combination with most commercial culture media with an efficiency similar to that of commercial substrates. It supported not only the long-term expansion of examined iPS and ES cell lines with normal karyotypes during their undifferentiated state but also directed differentiation of three germ layers. This substrate resolves major concerns associated with currently used recombinant protein substrates and could be applied in large-scale automated manufacturing; it is suitable for affordable and stable production of clinical-grade hPSCs and hPSC-derived products.
Topics: Cell Adhesion; Cell Culture Techniques; Cell Differentiation; Cell Line; Cell Self Renewal; Human Embryonic Stem Cells; Humans; Induced Pluripotent Stem Cells; Peptides; Polyvinyls; Tissue Scaffolds
PubMed: 35169157
DOI: 10.1038/s41598-022-06356-8 -
Proceedings of the National Academy of... Jul 2013Reading out the temperature-memory of polymers, which is their ability to remember the temperature where they were deformed recently, is thus far unavoidably linked to...
Reading out the temperature-memory of polymers, which is their ability to remember the temperature where they were deformed recently, is thus far unavoidably linked to erasing this memory effect. Here temperature-memory polymer actuators (TMPAs) based on cross-linked copolymer networks exhibiting a broad melting temperature range (ΔT(m)) are presented, which are capable of a long-term temperature-memory enabling more than 250 cyclic thermally controlled actuations with almost constant performance. The characteristic actuation temperatures T(act)s of TMPAs can be adjusted by a purely physical process, guiding a directed crystallization in a temperature range of up to 40 °C by variation of the parameter T(sep) in a nearly linear correlation. The temperature T(sep) divides ΔT(m) into an upper T(m) range (T > T(sep)) forming a reshapeable actuation geometry that determines the skeleton and a lower T(m) range (T < T(sep)) that enables the temperature-controlled bidirectional actuation by crystallization-induced elongation and melting-induced contraction. The macroscopic bidirectional shape changes in TMPAs could be correlated with changes in the nanostructure of the crystallizable domains as a result of in situ X-ray investigations. Potential applications of TMPAs include heat engines with adjustable rotation rate and active building facades with self-regulating sun protectors.
Topics: Hot Temperature; Polyethylenes; Polyvinyls
PubMed: 23836673
DOI: 10.1073/pnas.1301895110 -
Chemical & Pharmaceutical Bulletin 2018It is well known that high-pressure carbon dioxide (CO) lowers the glass transition temperature (T) of polymers. We therefore investigated whether T depression of...
It is well known that high-pressure carbon dioxide (CO) lowers the glass transition temperature (T) of polymers. We therefore investigated whether T depression of high-pressure CO results in interparticle bridging of a polymer and the tablet characteristics that makes the manufacture of an orally disintegrating tablet (ODT) possible. Copolyvidone (Kollidon) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus) were examined and found to exhibit a large T depression. Placebo ODTs were prepared and hardness, disintegration rate, porosity, and change in thickness and appearance were evaluated before and after the high-pressure CO treatment. This enabled the establishment of the optimal conditions for pressure, temperature, and treatment time under pressure. Experimental results showed that it was possible to manufacture ODTs comprising Kollidon as a water-soluble polymer with CO treatment under the suitable conditions such as temperature at 45°C, pressure lower than 8 MPa, and a treatment time shorter than 30 min, which is a new ODT manufacturing process called "Carbon Dioxide Assisted Tablet Formation Scheme" (CATS). In comparison to the conventional processes, which require high temperatures or humidity, CATS is expected to be applicable to drugs that are unstable at high temperature and humidity, and to functional drug particles used for bitter taste masking, sustained release, and other uses.
Topics: Administration, Oral; Carbon Dioxide; Drug Compounding; Glass; Particle Size; Polyethylene Glycols; Polymers; Polyvinyls; Povidone; Pressure; Surface Properties; Tablets; Transition Temperature
PubMed: 30270240
DOI: 10.1248/cpb.c18-00220 -
Journal of Applied Biomaterials &... 2022We aim to coat a novel polyvinyl benzyl chloride-D-glucaro-1, 4-lactonate polymer-coated bile duct stent for anti-biliary mud deposition and investigate its in vivo and...
BACKGROUND
We aim to coat a novel polyvinyl benzyl chloride-D-glucaro-1, 4-lactonate polymer-coated bile duct stent for anti-biliary mud deposition and investigate its in vivo and in vitro impacts. Biliary mud deposition is a leading cause of plastic biliary stent obstruction after its placement. Orally administrated D-glucaro-1, 4-lactonate is a specific competitive inhibitor of β-glucuronidase that causes biliary mud deposition.
METHODS
In this study, the stents coated with polyvinyl benzyl chloride-D-glucaro-1,4-lactonate polymer (PVBC-DGL) were placed in an ex vivo bile duct model perfused with porcine bile and observed every week until completely blocked. Post establishing the model of bile duct stenosis in piglets, stents are observed through endoscopy, hematology, patency time, and pathological changes within 6 months.
RESULTS
The 70% PVBC-DGL stents achieved the highest percentage of the inhibitory effect when the drugs were completely released in vitro. Results were obtained from 14 pigs (5: no coating (original), 4: 0% coating, and 5: 70% coating). The overall patency time of the stents was prolonged in all groups; however, the group with 70% coated stents showed a significantly prolonged patency time as compared to no coating (original) and the 0% coating groups in pigs (23.4 ± 1.8 vs 11.2 ± 2.1 w ( = 0.05); 23.4 ± 1.8 vs 10.5 ± 2.5 w ( = 0.05), respectively).
CONCLUSION
The stents with 70% PVBC-DGL better prevent and control the deposition of bile mud and prolong the patency time of stent placement in the subject animals and may be proposed for further clinical trials in patients.
Topics: Animals; Swine; Polyvinyls; Polymers; Stents; Bile Ducts
PubMed: 36366921
DOI: 10.1177/22808000221134988 -
BMC Research Notes Jun 2022Since there is no material in the market met all the ideal requirements of an impression material, thus in an attempt to find one, hybridization between the two most...
OBJECTIVE
Since there is no material in the market met all the ideal requirements of an impression material, thus in an attempt to find one, hybridization between the two most commonly used impression materials were done. The aim of the hybridization was to obtain a new material combining the good merits of both and eliminate their shortcomings. Thus, this study aimed to assess the impact of hybridization between polyether with addition silicone on tear strength and elastic recovery of the new material and compare such effect with regard to parent materials.
RESULTS
A polyether (PE), polyvinyl siloxanse (PVS) and vinyl polyether silicone (VPES) hybrid elastomers were used in the present study. Tear strength was measured one hour after setting time of each material according to the manufacturer and the three materials showed statistically comparable tear strength in N/mm. Elastic recovery was evaluated one minute after the setting time recommended by the manufacturer. The three materials were statistically insignificant from each other, and all met the ISO4823 requirement of having greater than 96.5% recovery.
Topics: Dental Impression Materials; Elasticity; Materials Testing; Polyvinyls; Resins, Synthetic; Silicone Elastomers; Surface Properties
PubMed: 35761301
DOI: 10.1186/s13104-022-06110-3 -
Clinical Oral Investigations Jul 2023Although a new super-quick setting polyether impression material has been commercially recently introduced, its properties have not been yet reported. Thus, it was the...
OBJECTIVES
Although a new super-quick setting polyether impression material has been commercially recently introduced, its properties have not been yet reported. Thus, it was the aim of this study to assess the dimensional stability, tear strength, and elastic recovery of the new material and to compare it with another commonly used polyether and polyvinyl siloxane.
MATERIALS AND METHODS
A new super-quick set polyether, a regular set polyether and a polyvinylsiloxane (PVS) impression material have been used in the study. Dimensional changes were measured using a modified mold as per ISO 4823:2000 after 1 h and 7 days. Tear strength was evaluated by subjecting specimens to tension until failure with a crosshead speed of 250 mm/min. Elastic recovery was measured by deforming specimens using a materials testing machine to a height of 16 mm (20% strain). The change in length (ΔL) was measured afterwards and elastic recovery was calculated in percentages.
RESULTS
Dimensional changes of the super quick and regular set polyether were comparable in both the vertical and horizontal dimensions after 24 h and 7 days. All the tested materials showed dimensional change values far below the maximum accepted ISO requirement (1.5%). The super quick setting polyether showed significantly improved tear strength (4.9 N/mm) in comparison to the regular set polyether (3.5 N/mm) and similar to PVS (5.2 N/mm). The elastic recovery of PVS (99.6%) was the highest among all the groups.
CONCLUSIONS AND CLINICAL RELEVANCE
The newly available super-fast set polyether offers a great potential for a reduced chair side time and comfort for both, the patient and the dentist. Super quick polyether showed as well improved tear strength, which is considered one of the shortcomings of the regular set polyether. In addition, the new polyether was as accurate as the regular set polyether and with good elastic recovery.
Topics: Humans; Dental Impression Materials; Siloxanes; Polyvinyls; Materials Testing
PubMed: 37017760
DOI: 10.1007/s00784-023-04982-8 -
Shokuhin Eiseigaku Zasshi. Journal of... 2023We determined the fifteen types of plasticizers, including four kinds of phthalic acid esters (PAEs) used in 220 polyvinyl chloride (PVC) toys on Japanese market from...
We determined the fifteen types of plasticizers, including four kinds of phthalic acid esters (PAEs) used in 220 polyvinyl chloride (PVC) toys on Japanese market from 2019 to 2020. Three kinds of previously undetected types of PAEs were also detected, but not identified in this study. Di (2-ethylhexyl) terephthalate (DEHTP) was the highest detection rate in 209 soft PVC toys out of 220 toys, with 71.2% for designated toys and 88.9% for not-designated toys, respectively, showing a gradual increase from the previous reports in 2009 and 2014. On the other hand, the usages of o-acetyl tributyl citrate and adipic acid esters decreased, but the six types of PAEs prohibited to use for the designated toys in Japan were not detected in them, the usage of diisobutyl phthalate were increased. In contrast, four types of PAEs were detected in not-designated toys. Among them, the detection ratio of di (2-ethyhexyl) phthalate decreased to about 1/10. The content levels of plasticizers in per each sample were continued to keep low level from the report five years ago. These results showed that the main plasticizer used in PVC toys is DEHTP, and that the usage of other plasticizers was decreased.
Topics: Plasticizers; Polyvinyl Chloride; Esters; Japan
PubMed: 37673604
DOI: 10.3358/shokueishi.64.145 -
Environmental Health Perspectives Oct 1976Poly(vinyl chloride) (PVC) is a complex plastic system. Individual components of the PVC system, including residual vinyl chloride monomer (RVCM) and certain additives,... (Review)
Review
Poly(vinyl chloride) (PVC) is a complex plastic system. Individual components of the PVC system, including residual vinyl chloride monomer (RVCM) and certain additives, may pose risks of harm to human health. There have been significant reductions in the RVCM content of PVC resin since 1974, reducing the cancer risk of workers in PVC fabrication plants and consumers of PVC products. A "no-effect" level for vinyl chloride monomer (VCM)-induced carcinogenesis has not been found to date; therefore, the significance of human exposure to low levels of RVCM remains to be determined. Exposure to PVC dust may cause pulmonary dysfunctions. Pulmonary and other possible health effects of PVC dust require further study. The PVC plastics system should be characterized as to interactions among its various components and as to interactions of the components and the PVC system as a whole with biological systems.
Topics: Air Pollutants, Occupational; Automobiles; Chemical Industry; Dust; Food Contamination; Government Agencies; Hemangiosarcoma; Humans; Industry; Liver Neoplasms; Occupational Diseases; Particle Size; Pneumoconiosis; Polyvinyl Chloride; Polyvinyls; United States; United States Food and Drug Administration; Vinyl Chloride
PubMed: 799961
DOI: 10.1289/ehp.7617107