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Scientific Reports Jul 2022An optimized mixture of polydopamine (PDA) and polyvinyl alcohol (PVA) is employed as the surface functionalizing agent and reducing agent to encapsulate individual...
An optimized mixture of polydopamine (PDA) and polyvinyl alcohol (PVA) is employed as the surface functionalizing agent and reducing agent to encapsulate individual polypropylene (PP) fibers of polypropylene micromembrane (PPMM). The functionalized PPMM becomes hydrophilic to allow the formation of Au nuclei for subsequent electroless Au deposition. The metalized PPMM is further deposited with IrO nanoparticles, and evaluated as a flexible and porous pH sensor. Images from scanning electron microscope confirms the uniform formation of IrO nanoparticles on Au-coated PP fibers. For pH-sensing performance, the IrO-decorated metalized PPMM reveals a super-Nernstian response for a sensing slope of -74.45 mV/pH in aqueous solutions with pH value ranging between 2 and 12. In addition, the pH-sensing performance is properly maintained after 5000 bending cycles and hysteresis is modest in an acidic environment. The cell viability test indicates a negligible bio-toxicity. Our strategy of using a conductive polymeric membrane decorated with IrO nanoparticles enables possible sensing applications in wearable and implantable electronics.
Topics: Electronics; Hydrogen-Ion Concentration; Nanoparticles; Polypropylenes; Polyvinyl Alcohol
PubMed: 35810194
DOI: 10.1038/s41598-022-15961-6 -
American Journal of Ophthalmology Oct 2021To optimize the flanged belt-loop technique of scleral fixation through biomechanical testing and report clinical outcomes of resultant modifications.
OBJECTIVE
To optimize the flanged belt-loop technique of scleral fixation through biomechanical testing and report clinical outcomes of resultant modifications.
DESIGN
Experimental study.
METHODS
The force to disinsert flanged polypropylene suture from human cadaveric sclera was assessed using a tensile testing machine and compared to the breaking strengths of 9-0 and 10-0 polypropylene. The effects of modifying suture gauge (5-0, 6-0, 7-0, or 8-0), amount of suture cauterized (0.5 or 1.0 mm), and sclerotomy size (27, 30, 32, 33 gauge) were investigated. Belt-loop intrascleral fixation using 6-0 and 7-0 polypropylene with 30 and 32 gauge needles, respectively, was performed in 4 patients. Main outcome measures were flanged suture disinsertion forces in cadaveric sclera.
RESULTS
The average force to disinsert a flange created by melting 1.0 mm of 5-0, 6-0, 7-0, and 8-0 polypropylene suture from human cadaveric sclera via 27, 30, 32, and 33 gauge needle sclerotomies was 3.0 ± 0.5 N, 2.1 ± 0.3 N, 0.9 ± 0.2 N, and 0.4 ± 0.1 N, respectively. The disinsertion forces for flanges formed by melting 0.5 mm of the same gauges were 72%-79% lower (P < .001). In comparison, the breaking strengths of 9-0 and 10-0 polypropylene were 0.91 ± 0.4 N and 0.52 ± 0.03 N. Belt-loop fixation using 6-0 and 7-0 polypropylene with 30 and 32 gauge sclerotomies demonstrated good outcomes at 6 months.
CONCLUSIONS
The flanged belt-loop technique is a biomechanically sound method of scleral fixation using 1.0 mm flanges of 5-0 to 7-0 polypropylene paired with 27, 30, and 32 gauge sclerotomies. In contrast, 8-0 polypropylene and 0.5 mm flanges of any suture gauge will likely be unstable with this technique.
Topics: Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Polypropylenes; Sclera; Suture Techniques; Sutures
PubMed: 33945819
DOI: 10.1016/j.ajo.2021.04.017 -
Materials (Basel, Switzerland) May 2023In order to study the influence of vinyl acetate-ethylene copolymerization emulsions on the bonding performance of fiber and mortar, mortar materials with different...
In order to study the influence of vinyl acetate-ethylene copolymerization emulsions on the bonding performance of fiber and mortar, mortar materials with different polymer contents were prepared. The optimal mix ratio of the matrix was obtained using a pull-out test with a 0° inclination angle. On this basis, polypropylene fibers and alkali-resistant glass fibers were set at different burial depths (6 mm, 12 mm, and 18 mm) and different burial angles (0°, 30°, 45°, and 60°). The load-displacement curves of two types of fibers pulled out from the polymer mortar were obtained. The test results show that polymer contents of 3% and 5% increase the peak pull-out loads of glass fibers and polypropylene fibers by 16.28% and 30.72% and 7.41% and 27.11%, respectively. When the polymer content is 7%, the peak pull-out load decreases by 1.31% and 24.26%, especially for polypropylene fiber, which significantly weakens the bonding performance between the matrix and the fiber. The pull-out load of glass fibers and polypropylene fibers increases with the increase in the buried depth, and both show tensile failure at 18 mm. As the embedding angle increases, the pull-out load of polypropylene fibers decreases continuously, while the glass fiber shows a higher pull-out load at 30°.
PubMed: 37176476
DOI: 10.3390/ma16093594 -
Scientific Reports Apr 2023Microplastics (MPs) are now a global issue due to increased plastic production and use. Recently, various studies have been performed in response to the human health...
Microplastics (MPs) are now a global issue due to increased plastic production and use. Recently, various studies have been performed in response to the human health risk assessment. However, these studies have focused on spherical MPs, which have smooth edges and a spherical shape and account for less than 1% of MPs in nature. Unfortunately, studies on fragment-type MPs are very limited and remain in the initial stages. In this study, we studied the effect that 16.4 µm fragment type polypropylene (PP) MPs, which have an irregular shape and sharp edges and form naturally in the environment, had on breast cancer. The detrimental effects of PPMPs on breast cancer metastasis were examined. Here, 1.6 mg/ml of PPMP, which does not induce cytotoxicity in MDA-MB-231, was used, and at this concentration, PPMP did not induce morphological changes or cellular migrating in the MDA-MB-231 and MCF-7 cells. However, PPMP incubation for 24 hours in the MDA-MB-231 cells significantly altered the level of cell cycle-related transcripts in an RNA-seq analysis. When confirmed by qRT-PCR, the gene expression of TMBIM6, AP2M1, and PTP4A2 was increased, while the transcript level of FTH1 was decreased. Further, secretion of the pro-inflammatory cytokine IL-6 from cancer cells was elevated with the incubation of PPMP for 12 hours. These results suggest that PPMP enhances metastasis-related gene expression and cytokines in breast cancer cells, exacerbating breast cancer metastasis.
Topics: Humans; Female; Breast Neoplasms; Polypropylenes; Microplastics; Plastics; Cytokines; Membrane Proteins; Apoptosis Regulatory Proteins; Protein Tyrosine Phosphatases
PubMed: 37069244
DOI: 10.1038/s41598-023-33393-8 -
Polymers Dec 2023Polyethylene (PE)-based elastomers are the ideal choice for enhancing the compatibility of polypropylene/polyethylene (PP/PE) blends and improving the mechanical...
Polyethylene (PE)-based elastomers are the ideal choice for enhancing the compatibility of polypropylene/polyethylene (PP/PE) blends and improving the mechanical properties of PP-based materials. However, the issue of blend systems lies in the interplay between the crystallization processes. Therefore, we investigated the crystallization behavior during the cooling process of a new generation of PP/PE block copolymers (PP-b-PE) and random polypropylene (PPR, a copolymer of propylene and a small amount of ethylene or an alpha-olefin) blends using in-situ X-ray diffraction/scattering and differential scanning calorimetry (DSC) techniques. We also conducted mechanical performance tests on PPR/PP-b-PE blends at room temperature and low temperature (-5 °C). The results indicate that during the cooling process, the PP phase of PP-b-PE will follow the PPR to crystallize in advance and form a eutectic mixture, thereby enhancing the compatibility of PP/PE. Moreover, the PPR/PP-b-PE blend will form stable β-(300) crystals with excellent mechanical properties. Due to the improved compatibility of PP/PE with PP-b-PE, PE crystals are dispersed within PP crystals, providing bonding that improves the toughness of PPR under the low stiffness failure conditions of PPR/PP-b-PE blends, thereby enhancing their impact performance at low and room temperatures. This research has great significance for both recycling waste plastics and enhancing the low-temperature toughness of PPR.
PubMed: 38139931
DOI: 10.3390/polym15244680 -
Materials (Basel, Switzerland) Aug 2022The disposal of steel slag leads to the occupation of large land areas, along with many environmental consequences, due to the release of poisonous substances into the...
The disposal of steel slag leads to the occupation of large land areas, along with many environmental consequences, due to the release of poisonous substances into the water and soil. The use of steel slag in concrete as a sand-replacement material can assist in reducing its impacts on the environment and can be an alternative source of fine aggregates. This is the very first paper that seeks to experimentally investigate the cumulative effect of steel slag and polypropylene fibers, particularly on the impact resistance of concrete. Various concrete mixes were devised by substituting natural sand with steel slag at volumetric replacement ratios of 0%, 10%, 20%, 30%, and 40%, with and without fibers. Polypropylene fibers of 12 mm length were introduced into the steel slag concrete at 0%, 0.5%, and 1.0% by weight of cement as a reinforcing material. Performance evaluation of each mix through extensive experimental testing indicated that the use of steel slag as partial substitution of natural sand, up to a certain optimum replacement level of 30%, considerably improved the compressive strength, flexural strength, and tensile strength of the concrete by 20.4%, 23.8%, and 17.0%, respectively. Furthermore, the addition of polypropylene fibers to the steel slag concrete played a beneficial role in the improvement of strength characteristics, particularly the flexural strength and final drop weight impact energy, which had a maximum rise of 48.1% and 164%, correspondingly. Moreover, integral structure and analytical analyses have also been performed in this study to validate the experimental findings. The results obtained encourage the use of fiber-reinforced steel slag concrete (FRSLC) as a potential impact-resistant material considering the environmental advantages, with the suggested substitution, of an addition ratio of 30% and 1.0% for steel slag and polypropylene fibers, respectively.
PubMed: 36013795
DOI: 10.3390/ma15165654 -
Environmental Research May 2023Pyrolysis oil from oil palm biomass can be a sustainable alternative to fossil fuels and the precursor for synthesizing petrochemical products due to its carbon-neutral...
Pyrolysis oil from oil palm biomass can be a sustainable alternative to fossil fuels and the precursor for synthesizing petrochemical products due to its carbon-neutral properties and low sulfur and nitrogen content. This work investigated the effect of applying mesoporous acidic catalysts, Ni-Mo/TiO and Ni/AlO in a catalytic co-pyrolysis of oil palm trunk (OPT) and polypropylene (PP) from 500 to 700 °C. The obtained oil yields varied between 12.67 and 19.50 wt.% and 12.33-17.17 wt.% for Ni-Mo/TiO and Ni/AlO, respectively. The hydrocarbon content in oil significantly increased up to 54.07-58.18% and 37.28-68.77% after adding Ni-Mo/TiO and Ni/AlO, respectively. The phenolic compounds content was substantially reduced to 8.46-20.16% for Ni-Mo/TiO and 2.93-14.56% for Ni/AlO. Minor reduction in oxygenated compounds was noticed from catalytic co-pyrolysis, though the parametric effects of temperature and catalyst type remain unclear. The enhanced deoxygenation and cracking of phenolic and oxygenated compounds and the PP decomposition resulted in increased hydrocarbon production in oil during catalytic co-pyrolysis. Catalyst addition also promoted the isomerization and oligomerization reactions, enhancing the formation of cyclic relative to aliphatic hydrocarbon.
Topics: Polypropylenes; Pyrolysis; Titanium; Hydrocarbons; Catalysis; Biomass; Biofuels; Hot Temperature
PubMed: 36841526
DOI: 10.1016/j.envres.2023.115550 -
Molecules (Basel, Switzerland) May 2021Dendrimers comprise a specific group of macromolecules, which combine structural properties of both single molecules and long expanded polymers. The three-dimensional... (Review)
Review
Dendrimers comprise a specific group of macromolecules, which combine structural properties of both single molecules and long expanded polymers. The three-dimensional form of dendrimers and the extensive possibilities for use of additional substrates for their construction creates a multivalent potential and a wide possibility for medical, diagnostic and environmental purposes. Depending on their composition and structure, dendrimers have been of interest in many fields of science, ranging from chemistry, biotechnology to biochemical applications. These compounds have found wide application from the production of catalysts for their use as antibacterial, antifungal and antiviral agents. Of particular interest are peptide dendrimers as a medium for transport of therapeutic substances: synthetic vaccines against parasites, bacteria and viruses, contrast agents used in MRI, antibodies and genetic material. This review focuses on the description of the current classes of dendrimers, the methodology for their synthesis and briefly drawbacks of their properties and their use as potential therapies against infectious diseases.
Topics: Animals; Anti-HIV Agents; Anti-Infective Agents; Bacterial Infections; Biotechnology; Catalysis; Communicable Diseases; Contrast Media; Dendrimers; Drug Delivery Systems; Drug Design; HIV Infections; Humans; Infectious Disease Medicine; Magnetic Resonance Imaging; Mice; Nanotechnology; Peptides; Polymers; Polypropylenes; SARS-CoV-2; Stereoisomerism; Tomography, X-Ray Computed; Virus Diseases; COVID-19 Drug Treatment
PubMed: 34072765
DOI: 10.3390/molecules26113304 -
Northern Clinics of Istanbul 2022Post-operative adhesion is a common problem in abdominal surgery. Especially, foreign materials are strong stimulus for the development of adhesions. The aim of this...
OBJECTIVE
Post-operative adhesion is a common problem in abdominal surgery. Especially, foreign materials are strong stimulus for the development of adhesions. The aim of this study was to investigate whether drug release material coated prosthetic mesh decreases intra-abdominal adhesion formation or not.
METHODS
5-Fluorouracil (5-FU) releasing "chitosan gels" were loaded to polypropylene and polyglactin-910 grafts. Polypropylene, polyglactin-910 grafts, chitosan gel, and 5-FU-loaded polyglactin 910, polypropylene grafts were used to cover abdominal defects of rats which were created under sterile conditions (n=84). Each group was divided into two subgroups (n=6). Subgroups were sacrificed on the 7 and 30 days.
RESULTS
The 7 day macroscopic examinations were similar. Polypropylene group was most adhesive group on the 30 day. There were less adhesions in chitosan gel and 5-FU-loaded groups. Capsule and capsule margins showed no difference on both the 7 and 30 days. Polypropylene-5-FU group and polypropylene-chitosan gel group showed significantly less macroscopic adhesions than polypropylene control group. Furthermore, polyglactin-910-chitosan gel group was less adhesive than polypropylene control group.
CONCLUSION
This study showed that 5-FU decreases the adhesions but the dosage and release kinetics need further investigations.
PubMed: 36685624
DOI: 10.14744/nci.2021.45548 -
Scientific Reports May 2024Through tests and micro-observations, the static and dynamic mechanical properties and microstructure of rubber concrete samples modified with varying amounts of silica...
Through tests and micro-observations, the static and dynamic mechanical properties and microstructure of rubber concrete samples modified with varying amounts of silica fume and polypropylene fiber content were explored. The results indicate that incorporation of silica fume and polypropylene fiber can effectively enhance the performance of rubber concrete. Moreover, at 10% and 0.1% of silica fume and polypropylene fiber content respectively, rubber concrete's compressive strength, splitting tensile strength, flexural strength, and dynamic compressive strength reached maxima. Furthermore, microstructure characteristic analysis indicated that inadequate adhesion between rubber particles and the matrix is responsible for compromised bearing capacity in unmodified rubber concrete. However, with the addition of silica fume and polypropylene fiber, the fiber binds the rubber particles closely with the matrix, while the silica fume fills the gaps between the matrix components. This combination results in rubber concrete with a denser internal structure and enhances its bearing capacity significantly.
PubMed: 38822129
DOI: 10.1038/s41598-024-63341-z