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Materials (Basel, Switzerland) Sep 2021The research reported in this paper aims to evaluate the epoxy injection technique used to strengthen fiber-reinforced self-compacting concrete (FRSCC) with high...
The research reported in this paper aims to evaluate the epoxy injection technique used to strengthen fiber-reinforced self-compacting concrete (FRSCC) with high strength. This method is carried out on ruptured concrete specimens to assess the efficiency of the epoxy resin adhesive injection retrofitting technique for strength and stiffness. Five FRSCC mixes were designed and placed using different types (steel and polypropylene) and contents (0%, 0.25%, and 0.45% by volume) of fibers. The fresh and mechanical properties in addition to the microstructure of produced mixes were evaluated to assess the impact of fibers on the behavior of FRSCC. Results showed that the workability of FRSCC is reduced by increasing steel or polypropylene fiber content; however, the rheological characteristics of placed mixes satisfied the European Guidelines for Self-Compacting Concrete recommendation for fresh concrete. Also, splitting tensile, flexural, and shear strengths were enhanced by increasing fiber content. The simultaneous application of epoxy injection in FRSCC for repairing damaged concrete beams was shown to be highly effective.
PubMed: 34639919
DOI: 10.3390/ma14195506 -
International Urogynecology Journal Apr 2022To assess the long-term satisfaction, cure rate and safety of a new titanium-covered transobturator tape compared to polypropylene tape for the treatment of stress...
INTRODUCTION AND HYPOTHESIS
To assess the long-term satisfaction, cure rate and safety of a new titanium-covered transobturator tape compared to polypropylene tape for the treatment of stress urinary incontinence (SUI).
METHODS
A prospective study was conducted with 151 patients. Seventy patients underwent transobturator sling surgery with titanium tape from 2011 to 2019, and a historical control group (CG) of 81 patients was treated with a noncoated tape and underwent incontinence surgery from 1999 to 2009. We compared patient-reported outcome measures (PROMs) with the incontinence outcome questionnaire (IOQ).
RESULTS
The median follow-up was 2½ years in both groups. Based on responses to the IOQ, a statistically significantly shorter time of recovery (IOQ 15: 21.3 ± 26.4 [TG], 40.2 ± 38.5 [CG], p = 0.02), improvement of sex life (IOQ 13: 34.1 ± 29.4 [TG] vs. 65.3 ± 35.6 [CG], p = 0.01) and less voiding dysfunction (IOQ 19: 30.9 ± 28.1 [CG], 9.3 ± 18.6 [TG], p = 0.01) were observed in the TG. Objectively, no postoperative urinary retention was observed in the TG, but four cases were described in the CG. Ten patients needed a reoperation for SUI in the CG compared to three in the TG (p = 0.03).
CONCLUSION
The titanium-covered transobturator sling had superior recovery time, improved sexual function and reduced reoperation rate compared to a historical polypropylene group.
Topics: Female; Humans; Male; Polypropylenes; Prospective Studies; Suburethral Slings; Titanium; Treatment Outcome; Urinary Incontinence; Urinary Incontinence, Stress; Urologic Surgical Procedures
PubMed: 34599671
DOI: 10.1007/s00192-021-04976-8 -
Journal of Materials Science. Materials... Nov 20233D printing technology is an emerging method that gained extensive attention from researchers worldwide, especially in the health and medical fields. Biopolymers are an... (Review)
Review
3D printing technology is an emerging method that gained extensive attention from researchers worldwide, especially in the health and medical fields. Biopolymers are an emerging class of materials offering excellent properties and flexibility for additive manufacturing. Biopolymers are widely used in biomedical applications in biosensing, immunotherapy, drug delivery, tissue engineering and regeneration, implants, and medical devices. Various biodegradable and non-biodegradable polymeric materials are considered as bio-ink for 3d printing. Here, we offer an extensive literature review on the current applications of synthetic biopolymers in the field of 3D printing. A trend in the publication of biopolymers in the last 10 years are focused on the review by analyzing more than 100 publications. Their application and classification based on biodegradability are discussed. The various studies, along with their practical applications, are elaborated in the subsequent sections for polyethylene, polypropylene, polycaprolactone, polylactide, etc. for biomedical applications. The disadvantages of various biopolymers are discussed, and future perspectives like combating biocompatibility problems using 3D printed biomaterials to build compatible prosthetics are also discussed and the potential application of using resin with the combination of biopolymers to build customized implants, personalized drug delivery systems and organ on a chip technologies are expected to open a new set of chances for the development of healthcare and regenerative medicine in the future.
Topics: Artificial Limbs; Biopolymers; Polyethylene; Polymers; Printing, Three-Dimensional; Polypropylenes
PubMed: 37982917
DOI: 10.1007/s10856-023-06765-9 -
Analytical and Bioanalytical Chemistry Feb 2022Plastics undergo successive fragmentation and chemical leaching steps in the environment due to weathering processes such as photo-oxidation. Here, we report the...
Plastics undergo successive fragmentation and chemical leaching steps in the environment due to weathering processes such as photo-oxidation. Here, we report the effects of leachates from UV-irradiated microplastics towards the chlorophyte Scenedesmus vacuolatus. The microplastics tested were derived from an additive-containing electronic waste (EW) and a computer keyboard (KB) as well as commercial virgin polymers with low additive content, including polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS). Whereas leachates from additive-containing EW and KB induced severe effects, the leachates from virgin PET, PP, and PS did not show substantial adverse effects in our autotrophic test system. Leachates from PE reduced algae biomass, cell growth, and photosynthetic activity. Experimental data were consistent with predicted effect concentrations based on the ionization-corrected liposome/water distribution ratios (D) of polymer degradation products of PE (mono- and dicarboxylic acids), indicating that leachates from weathering PE were mainly baseline toxic. This study provides insight into algae toxicity elicited by leachates from UV-weathered microplastics of different origin, complementing the current particle- vs. chemical-focused research towards the toxicity of plastics and their leachates.
Topics: Electronic Waste; Microalgae; Microplastics; Polyethylene; Polypropylenes; Polystyrenes; Scenedesmus; Ultraviolet Rays; Water Pollutants, Chemical
PubMed: 34936008
DOI: 10.1007/s00216-021-03798-3 -
Environmental Pollution (Barking, Essex... Aug 2022Plastics are produced and used in large quantities worldwide (e.g. as food packaging). In line with this, plastic particles are found throughout the ecosphere and in...
Plastics are produced and used in large quantities worldwide (e.g. as food packaging). In line with this, plastic particles are found throughout the ecosphere and in various foods. As a result, plastics are also present in energy-rich waste biomass derived from the food industry, supermarkets, restaurants, etc. These waste streams are a valuable source for biogas production but can also be used to feed insects that in turn upcycle it into new high-value biomass. In both applications, the remaining residue can be used as fertilizer. Due to the present plastic particles, these applications could pose a continued threat to the environment, and both human and animal health. Therefore, the need of determining the (micro)plastic content to assess the potential danger is rising. In this research, a closed-vessel microwave-assisted acid digestion method was developed to accurately determine meso- and microplastic contents in food (waste) matrices by solubilising this food matrix. Polyvinyl chloride (PVC) food packaging foil was used to develop the method, using a full factorial design with three parameters (nitric acid concentration (c(HNO)), temperature (T), and time (t)). According to this model, the best practical conditions were c(HNO) = 0.50 mol/L, T = 170 °C, and t = 5.00 min. Subsequently, the method was tested on five other plastics, namely high- and low-density polyethylene (HDPE and LDPE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET), mixed with a food matrix, resulting in a mean plastic recovery of 102.2 ± 4.1%. Additionally, the polymers were not oxidised during the microwave digestion. For PVC and PS hardly any degradation was found, while HDPE, LDPE, and PP showed slight chain degradation, although without recovery loss. In conclusion, the method is an accurate approach to quantify the total meso- and microplastic content in food (waste) matrices with minimal change in their intrinsic characteristics.
Topics: Animals; Food; Microplastics; Plastics; Polyethylene; Polypropylenes; Polystyrenes; Polyvinyl Chloride; Refuse Disposal
PubMed: 35613682
DOI: 10.1016/j.envpol.2022.119511 -
PloS One 2020Microplastics (MPs) are omnipresent in the environment, including the human food chain; a likely important contributor to human exposure is drinking water.
BACKGROUND
Microplastics (MPs) are omnipresent in the environment, including the human food chain; a likely important contributor to human exposure is drinking water.
OBJECTIVE
To undertake a systematic review of MP contamination of drinking water and estimate quantitative exposures.
METHODS
The protocol for the systematic review employed has been published in PROSPERO (PROSPERO 2019, Registration number: CRD42019145290). MEDLINE, EMBASE and Web of Science were searched from launch to the 3rd of June 2020, selecting studies that used procedural blank samples and a validated method for particle composition analysis. Studies were reviewed within a narrative analysis. A bespoke risk of bias (RoB) assessment tool was used.
RESULTS
12 studies were included in the review: six of tap water (TW) and six of bottled water (BW). Meta-analysis was not appropriate due to high statistical heterogeneity (I2>95%). Seven studies were rated low RoB and all confirmed MP contamination of drinking water. The most common polymers identified in samples were polyethylene terephthalate (PET) and polypropylene (PP), Methodological variability was observed throughout the experimental protocols. For example, the minimum size of particles extracted and analysed, which varied from 1 to 100 μm, was seen to be critical in the data reported. The maximum reported MP contamination was 628 MPs/L for TW and 4889 MPs/L for BW, detected in European samples. Based on typical consumption data, this may be extrapolated to a maximum yearly human adult uptake of 458,000 MPs for TW and 3,569,000 MPs for BW.
CONCLUSIONS
This is the first systematic review that appraises the quality of existing evidence on MP contamination of drinking water and estimates human exposures. The precautionary principle should be adopted to address concerns on possible human health effects from consumption of MPs. Future research should aim to standardise experimental protocols to aid comparison and elevate quality.
Topics: Drinking Water; Environmental Monitoring; Food Chain; Microplastics; Polyethylene Terephthalates; Polypropylenes; Public Health; Water Pollutants, Chemical
PubMed: 32735575
DOI: 10.1371/journal.pone.0236838 -
Heart Rhythm Jul 2023Transvenous lead extraction has been possible since the 1980s. However, complications during lead extraction, such as the distal end fragment of the lead remaining in...
BACKGROUND
Transvenous lead extraction has been possible since the 1980s. However, complications during lead extraction, such as the distal end fragment of the lead remaining in the myocardium or venous system and injury to the veins or heart, have been reported.
OBJECTIVE
The purpose of this study was to examine our method for complete removal of a separated lead, as extraction of long-term implanted devices is difficult using standard methods and may require additional procedures. The removal of leads with inner conductor coil and lead tip separated from outer insulation, conductor coil, and proximal ring electrode using a multipurpose catheter is reported.
METHODS
In total, 345 consecutive patients who underwent transvenous lead extraction (TLE) from April 2014 to March 2021 were retrospectively analyzed. Lead characteristics, device type, and indications for extraction were further analyzed in 20 patients who developed separation of the proximal ring electrode and outer conductor coil from the inner conductor and distal tip at the time of extraction.
RESULTS
Extractions were performed using an excimer laser sheath laser and a Byrd polypropylene telescoping sheath (n = 15); laser, Byrd polypropylene telescoping sheath, and Evolution RL (n = 2); laser and Evolution RL (n = 3); Byrd polypropylene telescoping sheath and Evolution RL (n = 1); Byrd polypropylene telescoping sheath only (n = 4); and Evolution RL only (n = 2). Twenty-seven leads implanted for more than 10 years had lead separation. A multipurpose catheter was used to protect the fragile leads from further damage. All leads were completely extracted.
CONCLUSION
All distal tip-to-proximal ring electrode separated leads were successfully removed using laser and other sheaths with the assistance of a multipurpose catheter, without any part of the leads remaining in the heart.
Topics: Humans; Electrodes, Implanted; Pacemaker, Artificial; Retrospective Studies; Polypropylenes; Device Removal; Defibrillators, Implantable; Catheters; Treatment Outcome
PubMed: 37001747
DOI: 10.1016/j.hrthm.2023.03.209 -
Environmental Science and Pollution... Sep 2023Butachlor (BUT) is a widely used herbicide that can cause environmental problems when used excessively. BUT has been found to exist in large quantities in the water...
Butachlor (BUT) is a widely used herbicide that can cause environmental problems when used excessively. BUT has been found to exist in large quantities in the water environment so far. As an agricultural pre-emergent herbicide, BUT can enter the water environment through multiple channels and cause pollution. This study investigated the mechanism of three types of microplastics (MPs): polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC) to remove BUT from water. The adsorption behavior between MPs and BUT under different factors, namely pH, salt ion concentration, and aging, was investigated. This study further investigated the desorption and aging of BUT-adsorbed MPs. In this research, the adsorption capacity of BUT by PE, PP, and PVC are 13.65 μg/g, 14.82 μg/g, and 18.88 μg/g, respectively, and the order of carrier effect was: PVC>PP>PE. Experiments show that MPs have low adsorption performance on the microgram level for BUT. The adsorption behavior of PE, PP, and PVC on BUT conformed to pseudo-second-order kinetics, indicating the presence of physical and chemical adsorption. The Langmuir isotherm model fits well, indicating that the adsorption is a single-layer adsorption process. The pH value causes slight fluctuations in the overall carrier effect. Low concentration of salt ions can inhibit the carrier effect, and high concentration will promote the interaction between MPs and BUT. Aging experiments show that the carrier effect of the original materials was higher than the adsorption capacity of hydrogen peroxide and MPs after acid aging, and acid aging can cause the adsorption capacity to drop significantly.
Topics: Microplastics; Plastics; Water; Polypropylenes; Polyethylene; Adsorption; Herbicides; Water Pollutants, Chemical
PubMed: 36112288
DOI: 10.1007/s11356-022-23027-3 -
ACS Biomaterials Science & Engineering Aug 2022Polypropylene (PP) surgical meshes, with different knitted architectures, were chemically functionalized with gold nanoparticles (AuNPs) and 4-mercaptothiazole (4-MB) to...
Polypropylene (PP) surgical meshes, with different knitted architectures, were chemically functionalized with gold nanoparticles (AuNPs) and 4-mercaptothiazole (4-MB) to transform their fibers into a surface enhanced Raman scattering (SERS) detectable plastic material. The application of a thin layer of poly[-isopropylacrylamide---methylene bis(acrylamide)] (PNIPAAm--MBA) graft copolymer, covalently polymerized to the mesh-gold substrate, caused the conversion of the inert plastic into a thermoresponsive material, resulting in the first PP implantable mesh with both SERS and temperature stimulus responses. AuNPs were homogeneously distributed over the PP yarns, offering a clear SERS recognition together with higher PNIPAAm lower critical solution temperature (LCST ∼ 37 °C) than without the metallic particles (LCST ∼ 32 °C). An infrared thermographic camera was used to observe the polymer-hydrogel folding-unfolding process and to identify the new value of the LCST, connected with the heat generation by plasmonic-resonance gold NPs. The development of SERS PP prosthesis will be relevant for the bioimaging and biomarker detection of the implant by using the plasmonic effect and Raman vibrational spectroscopy for minimally invasive interventions (such as laparoscopy), to prevent patient inflammatory processes. Furthermore, Raman sources have been proved to not damage the cells, like happens with near-infrared irradiation, representing another advantage of moving to SERS approaches. The findings reported here offer unprecedented application possibilities in the biomedical field by extrapolating the material functionalization to other nonabsorbable polymer made devices (e.g., surgical sutures, grapes, wound dressings, among others).
Topics: Gold; Humans; Hydrogels; Metal Nanoparticles; Polypropylenes; Spectrum Analysis, Raman
PubMed: 35653133
DOI: 10.1021/acsbiomaterials.2c00334 -
European Journal of Trauma and... Dec 2022High clinical success rates have been reported with the Masquelet technique in the treatment of traumatic bone loss. An increasing number of studies suggest that various... (Review)
Review
PURPOSE
High clinical success rates have been reported with the Masquelet technique in the treatment of traumatic bone loss. An increasing number of studies suggest that various factors can influence the properties of induced membranes. Goal of this systematic review is to answer the following questions: (1) which are the ideal spacer properties (material, surface topography, antibiotic supplementation) to booster the quality and osteogenic potential of induced membranes? (2) what is the ideal time to perform the second-stage operation?
METHODS
A systematic search using the keywords "((Masquelet) OR (Induced Periosteum)) AND ((Spacer) OR (Time))" was performed in PubMed, Embase and Cochrane Library according to PRISMA guidelines. Studies published up to the 23rd of February 2022 were included and assessed independently by two reviewers.
RESULTS
Thirteen animal and 1 clinical studies were identified to address the above questions. Spacer materials used were PMMA, silicone, titanium, polypropylene, PVA, PCL and calcium sulfate. With the exception of PVA sponges, all solid materials could induce membranes. Low union rates have been reported with titanium and rough surfaced spacers. Scraping of the inner surface of the IM also increased bony union rates. In terms of the ideal timing to perform the second-stage evidence suggests that membranes older than 8 weeks continue to have regenerative capacities similar to younger ones.
CONCLUSION
Membranes induced by smooth PMMA spacers loaded with low concentrations of antibiotics showed powerful osteogenic properties. Other materials such as Polypropylene or Calcium sulfate can also be used with good results. Despite current recommendation to perform the second stage operation in 4-8 weeks, membranes older than 8 weeks seem to have similar regenerative capacities to younger ones.
Topics: Animals; Polymethyl Methacrylate; Titanium; Calcium Sulfate; Polypropylenes
PubMed: 35726029
DOI: 10.1007/s00068-022-02005-x