Effect of Chemical Treatments on the Mechanical Properties of Jute/Polyester Composites.

Natural fiber composites have been extensively studied for structural applications, with recent exploration into their potential for various uses. This study investigates the impact of chemical treatments on the properties of Brazilian jute woven fabric/polyester resin composites. Sodium hydroxide, hydrogen peroxide, and peracetic acid were utilized to treat the jute fabrics, followed by resin transfer molding (RTM) to form the composites. Evaluation included water absorption, flexural strength, tensile strength, and short-beam strength. The alkaline treatment induced changes in the chemical composition of the fibers' surface. Chemical treatments resulted in increased flexural and short-beam strength of the composites, with no significant alterations in tensile properties. The hydrogen peroxide treatment exhibited lower water absorption, suggesting its potential as a viable option for enhancing the performance of these composites.

In vivo evaluation of a polyester and fiberglass composite intramedullary nail for femoral osteosynthesis in calves.

The objective of this study was to test a composite of polyester resin and fiberglass in the form of an intramedullary nail for osteosynthesis of femoral fractures in calves. The methodology was established based on a previous study that used a bovine femur finite element model to simulate fractures, which were then stabilized by the same nails as proposed in this study. General anesthesia was induced in six calves followed by fracture creation via an oblique incision in the middle third of the femoral diaphysis, and osteosynthesis was immediately performed by retrograde insertion of the composite nail. Locking was achieved by drilling the bone and nail without using a jig and introducing two stainless steel screws proximal and two distal to the fracture line. Five of the six calves achieved complete fracture healing after 60 days. No signs of incompatibility or toxicity of the composite were observed. However, limitations were observed during the surgery, such as difficulty in drilling the nail and trimming the remainder portion of the nail that extended beyond the length of the bone. Small fragments produced by these maneuvers were considered irritating to soft tissues during the postoperative period. It was also found that small cracks in the nail tended to propagate in the form of longitudinal fractures. In conclusion, an intramedullary nail made of polyester resin and fiberglass (a low-cost and easy-to-acquire material) was considered biocompatible and capable of allowing bone healing of femoral fractures in young cattle. However, the development of solutions for the reported limitations is crucial prior to recommending the proposed composite for clinical use.

Effect of Hydrothermal Aging on Damping Properties in Sisal Mat-Reinforced Polyester Composites.

Hydrothermal aging is a matter of considerable concern for natural fiber-reinforced polymers; it can alter dimensional stability and induce microcracks and macro strain on the composite structure. This study applied a sorption kinetic model and examined the effects of water on the damping factor of sisal mat-reinforced polyester composites. The experimental data were fitted well using a Boltzmann sigmoid function, suggesting a promising first step toward kinetic water sorption modeling. Additionally, a damping test was carried out using the impulse excitation technique, highlighting the composite material's dynamic response under varying water absorption conditions. The result showed that damping exhibited sensitivity to water absorption, increasing significantly during the first 24 h of immersion in water, then remained steady over time, inferring a critical time interval. An empirical model proved satisfactory with the correlation coefficient for sorption rates and damping of sisal mat polymeric composites.

Recent Developments in Synthesis, Properties, Applications and Recycling of Bio-Based Elastomers.

In 2021, global plastics production was 390.7 Mt; in 2022, it was 400.3 Mt, showing an increase of 2.4%, and this rising tendency will increase yearly. Of this data, less than 2% correspond to bio-based plastics. Currently, polymers, including elastomers, are non-recyclable and come from non-renewable sources. Additionally, most elastomers are thermosets, making them complex to recycle and reuse. It takes hundreds to thousands of years to decompose or biodegrade, contributing to plastic waste accumulation, nano and microplastic formation, and environmental pollution. Due to this, the synthesis of elastomers from natural and renewable resources has attracted the attention of researchers and industries. In this review paper, new methods and strategies are proposed for the preparation of bio-based elastomers. The main goals are the advances and improvements in the synthesis, properties, and applications of bio-based elastomers from natural and industrial rubbers, polyurethanes, polyesters, and polyethers, and an approach to their circular economy and sustainability. Olefin metathesis is proposed as a novel and sustainable method for the synthesis of bio-based elastomers, which allows for the depolymerization or degradation of rubbers with the use of essential oils, terpenes, fatty acids, and fatty alcohols from natural resources such as chain transfer agents (CTA) or donors of the terminal groups in the main chain, which allow for control of the molecular weights and functional groups, obtaining new compounds, oligomers, and bio-based elastomers with an added value for the application of new polymers and materials. This tendency contributes to the development of bio-based elastomers that can reduce carbon emissions, avoid cross-contamination from fossil fuels, and obtain a greener material with biodegradable and/or compostable behavior.

Revealing the Structure Formation on Polyglycerol Citrate Polymers-An Environmentally Friendly Polyester as a Seed-Coating Material.

A detailed structural investigation of a promising bio-based polymer, polyglycerol citrate polyester, obtained by the bulk polycondensation of glycerol (Gly) against citric acid (Cit) under mild reaction was performed. The reaction in conditions with and without catalyst use (sulfuric acid, H2SO4) was investigated, showing evidence that it is possible to modify the polymer solubility according to the ratio and catalyst utilization. 13C and 1H NMR indicated that synthesis catalyzed with Cit excess leads to higher esterification degrees of citrate groups. In contrast, the Gly moieties are more prominent in catalyzed polymers regardless of the excess monomers. Overall, a successful conversion of Gly and Cit into polyesters was attained even without catalysis, enabling a simple route for the large-scale production of this green material to be used as a coating material. This polymer has been shown to be well-suited for coating seeds and might be a promising material for similar agricultural applications. Tests on soybean seed coating with a PGCit solution of 75% indicated that the seed quality and germination rate were not affected by the PGCit coating, concluding that this polymer is suitable for this application.

Polyester urethane urea (PEUU) functionalization for enhanced anti-thrombotic performance: advancing regenerative cardiovascular devices through innovative surface modifications.

Introduction: Thrombogenesis, a major cause of implantable cardiovascular device failure, can be addressed through the use of biodegradable polymers modified with anticoagulating moieties. This study introduces a novel polyester urethane urea (PEUU) functionalized with various anti-platelet deposition molecules for enhanced antiplatelet performance in regenerative cardiovascular devices. Methods: PEUU, synthesized from poly-caprolactone, 1,4-diisocyanatobutane, and putrescine, was chemically oxidized to introduce carboxyl groups, creating PEUU-COOH. This polymer was functionalized in situ with polyethyleneimine, 4-arm polyethylene glycol, seleno-L-cystine, heparin sodium, and fondaparinux. Functionalization was confirmed using Fourier-transformed infrared spectroscopy and X-ray photoelectron spectroscopy. Bio-compatibility and hemocompatibility were validated through metabolic activity and hemolysis assays. The anti-thrombotic activity was assessed using platelet aggregation, lactate dehydrogenase activation assays, and scanning electron microscopy surface imaging. The whole-blood clotting time quantification assay was employed to evaluate anticoagulation properties. Results: Results demonstrated high biocompatibility and hemocompatibility, with the most potent anti-thrombotic activity observed on pegylated surfaces. However, seleno-L-cystine and fondaparinux exhibited no anti-platelet activity. Discussion: The findings highlight the importance of balancing various factors and addressing challenges associated with different approaches when developing innovative surface modifications for cardiovascular devices.

The Evolution and Future Trends of Unsaturated Polyester Biocomposites: A Bibliometric Analysis.

Unsaturated polyester resin (UPR) is one of the first commercialized polymer matrices for composites reinforced with glass fibers, but has remained popular to this day. To reduce their environmental impact, natural fibers have been used as reinforcements. Researchers all over the world are still interested in these composites, and numerous papers have been published in the last four decades. Using bibliometric analysis, this work provides compiled, structured, and relevant information about the evolution and current state of these materials. This first study on UPR biocomposites based on bibliometric analysis examined 531 published papers identified in the Scopus database from 1982 to July 2022. An analysis of the most active states, leading institutions, and leading authors is followed by the identification of key areas such as the most common natural fibers used as reinforcements, fiber treatments, and composite design parameters such as processing techniques; recently, composite testing; and technological applications. The findings emphasize the importance of staying active in this global field and provide information on novel promising topics for future research.

Consumption of commercially sold dried fish snack "Charales" contaminated with microplastics in Mexico.

Inadvertent human exposure to microplastics by the ingestion of microplastic-contaminated processed foods poses health risks and new preventative issues; nevertheless, investigations analyzing microplastic occurrences in commercially dried fish for direct human consumption are scarce. This study assessed the abundance and characteristics of microplastics in 25 commercially sold dried fish products (4 supermarkets, 3 street vendors, and 18 traditional agri-product farmers' markets) from two widely consumed and commercially important Chirostoma species (C. jordani and C. patzcuaro) in Mexico. Microplastics were detected in all the samples examined, with abundances ranging from 4.00 ± 0.94 to 55.33 ± 9.43 items g-1. C. jordani dried fish samples had higher mean microplastic abundance (15.17 ± 5.90 items g-1) than the C. patzcuaro dried fish samples (7.82 ± 2.90 items g-1); nevertheless, there was no statistically significant difference in microplastic concentrations between the samples. The most prevalent type of microplastic was fiber (67.55%), followed by fragment (29.18%), film (3.00%), and sphere (0.27%). Non-colored microplastics (67.35%) predominated, while microplastic sizes varied from 24 to 1670 µm, with sizes less than 500 µm (84%) being the most common. ATR-FTIR analysis revealed polyester, acrylonitrile butadiene styrene, polyvinyl alcohol, ethylene-propylene copolymer, nylon-6 (3), cellophane, and viscose in the dried fish samples. Overall, this study's findings are the first in Latin America to demonstrate microplastic contamination in dried fish for human consumption, underscoring the need for developing countermeasures to prevent plastic pollution in fish-caught regions and reduce the risks of human exposure to these micropollutants.

Tailoring/Tuning Properties of Polyester Urea-Urethanes through Hybridization with Titania Obtained Using the Sol-Gel Process.

Hybrid materials have been studied because in these materials the properties of organic components, such as elasticity and biodegradability, could be combined with the properties of inorganic components, such as good biological response, thereby transforming them into a single material with improved properties. In this work, Class I hybrid materials based on polyester-urea-urethanes and titania were obtained using the modified sol-gel method. This was corroborated using the FT-IR and Raman techniques which highlighted the formation of hydrogen bonds and the presence of Ti-OH groups in the hybrid materials. In addition, the mechanical and thermal properties and degradability were measured using techniques, such as Vickers hardness, TGA, DSC, and hydrolytic degradation; these properties could be tailored according to hybridization between both organic and inorganic components. The results show that Vickers hardness increased by 20% in hybrid materials as compared to polymers; also, the surface hydrophilicity increases in the hybrid materials, improving their cell viability. Furthermore, cytotoxicity in vitro test was carried out using osteoblast cells for intended biomedical applications and they showed non-cytotoxic behavior.

Abundance and composition of microplastics in Tampico beach sediments, Tamaulipas State, southern Gulf of Mexico.

The abundance and characteristics of microplastics (MPs) in coastal sediments from the Tampico beach, Gulf of Mexico was investigated. The MPs were extracted by a density separation method with saturated solutions of NaCl and ZnCl2, the sediment-solution relationship was 1:3. MPs were classified according to its shape, color, and size under a stereoscopic microscope. Identification of MPs surface was carried out by a Scanning Electron Microscope (SEM). The polymer types were detected by a Fourier-transformed infrared (FTIR) Spectroscopy. Number of MPs in 20 g of sediments varies from 256 to 283 particles. The average abundance of MPs per kg was inferred as ∼13,392 microplastic particles. Fiber was the only MP particle identified in the Tampico beach, its size varied from 1.76 mm to 3.92 mm. Fibers identified were mostly transparent, blue, white, black, multicolor, yellow, pink, and red. Six different polymers were identified, i.e., polyester (PES), polyethylacrylate (PEA), cellophane, polyacrylonitrile (PAN), polystyrene acrylonitrile (SAN), and polyvinyl acetate ethylene (PVAE). PES is the most prevalent polymer in all samples.

PEGylated and functionalized polylactide-based nanocapsules: An overview.

Polymeric nanocapsules (NC) are versatile mixed vesicular nanocarriers, generally containing a lipid core with a polymeric wall. They have been first developed over four decades ago with outstanding applicability in the cosmetic and pharmaceutical fields. Biodegradable polyesters are frequently used in nanocapsule preparation and among them, polylactic acid (PLA) derivatives and copolymers, such as PLGA and amphiphilic block copolymers, are widely used and considered safe for different administration routes. PLA functionalization strategies have been developed to obtain more versatile polymers and to allow the conjugation with bioactive ligands for cell-targeted NC. This review intends to provide steps in the evolution of NC since its first report and the recent literature on PLA-based NC applications. PLA-based polymer synthesis and surface modifications are included, as well as the use of NC as a novel tool for combined treatment, diagnostics, and imaging in one delivery system. Furthermore, the use of NC to carry therapeutic and/or imaging agents for different diseases, mainly cancer, inflammation, and infections is presented and reviewed. Constraints that impair translation to the clinic are discussed to provide safe and reproducible PLA-based nanocapsules on the market. We reviewed the entire period in the literature where the term "nanocapsules" appears for the first time until the present day, selecting original scientific publications and the most relevant patent literature related to PLA-based NC. We presented to readers a historical overview of these Sui generis nanostructures.

Evaluation of Light Cementitious Matrix with Composite Textile Reinforcement from Garment Waste.

The use of recycled waste has been the focus of several studies due to its potential to allow a more sustainable use of construction materials and minimize improper waste disposal in landfills or incinerators. More specifically, garment textile waste has been examined as internal reinforcement of cementitious matrices to increase the deformability and control fissure formation. In this study, polyester textiles are analyzed and incorporated in cementitious composites in order to evaluate their mechanical properties. Results show that significant improvements in mechanical properties of composites are obtained depending on the impregnation treatment applied to the textile waste. In the direct tensile stress test, the waste impregnation with styrene butadiene polymer plus silica fume improved 35.95% in the weft direction and 9.33% in the warp direction. Maximum stress increased 53.57% and 64.48% for composites with styrene-butadiene rubber impregnation and styrene-butadiene rubber plus silica fume impregnation, respectively, when compared to the unreinforced composite. The flexural tensile strength of composites impregnated reinforcements with styrene-butadiene rubber and styrene-butadiene rubber plus silica fume presented increases in strength by 92.10% and 94.73%, respectively, when compared to the unreinforced sample. The impact test confirmed that styrene-butadiene rubber plus silica fume impregnation produced greater tenacity of the composite. In the microstructure, it is confirmed that the impregnated textile reinforcement resulted in composites with greater adhesion between the fabric and the cementitious matrix. Thus, light textile waste is concluded to be a viable construction material for non-structural elements.

Microplastics incorporated by honeybees from food are transferred to honey, wax and larvae.

Microplastics (MP) are ubiquitous in the environment, and there is little information available on their impact on terrestrial organisms. Their effect on insects and particularly on honeybees is relevant, given the prevalence of these organisms in the environment and the fact that they provide key ecosystem services. We conducted a field study to assess (1) the fate of these ingested MP within the hive, and (2) MP effect on Apis mellifera population growth during chronic exposure. We aimed to determine if MP ingested by honeybees are incorporated into hive matrices, including honey, and their effect on colony development and honey reserves. We fed beehives with sucrose solutions treated or untreated with 50 mg of Polyester microfibers/L for one month. Microplastic fibers (MF) from treated syrup were incorporated by adult worker bees, remaining in their cuticle, digestive tract, larvae, honey, and wax. Most of the MF were accumulated in wax showing that honey remains as a safe food. At the end of the experiment, no differences in honey reserves or bee population were observed. This is the first study to evaluate in the field the effects and dynamics of MP inside honeybee hives. Our results showed that bees can incorporate MP from the environment and deliver them into the different matrices of the hive. Concentration of MF found in honey of treated hives was like that found in commercial honey, suggesting that honeybees might be exposed to similar MP contamination levels in the environment compared to our experiment. Finally, our results highlight a way in which MP might enter the food chain, with direct implication for human health.

3D printed matrix solid forms: Can the drug solubility and dose customisation affect their controlled release behaviour?

The use of 3D printing in pharmaceutics has grown over the last years, along with the number of studies on the impact of the composition of these formulations on their pharmaceutical and biopharmaceutical properties. Recently, we reported the combined effect of the infill percentage and the presence of a pore former on the drug release behaviour of 3D printed matrix solid forms prepared by fused deposition modelling. However, there are some open questions about the effect of the drug solubility and the size of these dosage forms on their controlled release properties. Therefore, we produced poly(Ɛ-caprolactone) filaments containing different soluble forms of dexamethasone (free acid, DEX; acetate ester, DEX-A; and phosphate salt, DEX-P), which showed suitable mechanical properties and printability. 3D printed solid forms were produced in two different sizes. The formulations composed of DEX-P released about 50% of drug after 10 h, while those containing DEX or DEX-A released about 9%. The drug release profiles from the 3D printed forms containing the same drug form but with different sizes were almost completely overlapped. Therefore, these 3D printed matrix solid forms can have their drug content customised by adjusting their size, without changing their controlled release behaviour.

Is domestic polyester suitable for plastination of thin brain slices?

Plastination is a technique used to preserve biological tissues while retaining most of their original appearance. In the technique, developed by Dr. Gunther von Hagens in 1977, specimens were impregnated with a polymer, such as silicone, epoxy, or polyester. Considered the most suitable material for brain plastination, polyester has a wide application in teaching and research compared with imaging techniques. The materials for plastination are usually imported from Germany and more expensive than domestic products. If domestic polymers were to enter the market it would favor the expansion of plastination in Brazil. Hence, this study evaluated the feasibility of using domestic polyesters to replace the usual Biodur® (P40) in plastination of brain slices. For this evaluation, 2-mm-thick sections of bovine brains were prepared and plastinated with domestic polyester. Slices were compared before impregnation and after curing using standardized photographs taken after dehydration and after curing. Plastination followed the standard protocol: fixation, dehydration, forced impregnation, and curing. Fifteen brain slices were plastinated with each polyester (P40, P18, and C1-3). There was no significant difference in the percent shrinkage between groups after plastination of P18 and P40, but the curing time of Cristalan© polymer was too short for impregnation. Therefore, no initiator was used for C polymers impregnation. Thus, domestic polyester P18 was a viable option for the process.

Hybrid Coatings of SiO2-Recycled PET Unsaturated Polyester Resin by Sol-Gel Process.

Hybrid coatings of SiO2 and recycled unsaturated polyester resin (R-UPR) from recycled polyethylene-terephthalate (PET) were prepared by the sol-gel process on glass substrates. First, SiO2 was synthesized by the sol-gel process using a tetraethyl orthosilicate (TEOS) solution. Next, bis(2-hydroxypropyl-terephthalate) (BHPT) was synthesized from mechanical and chemical recycling (glycolysis) of post-consumer PET bottles in propylene glycol (PG) using ZnA as catalyst, in a Vessel-type reactor (20-200 °C); maleic anhydride (MA) was added and, following the same procedure, the unsaturated polyester (UP) was synthetized, which was cooled to room temperature. Next, styrene (St) and benzoyl-peroxide (PBO)-initiator were added to obtain R-UPR. TEOS (T) and three hybrid solutions were synthesized, with molar ratios of 0:1:0 (T), 1:2:0.25 (H1), 1:1:0.25 (H2), and 1:0:0.25 (H3) for R-UPR:TEOS:3-trimethoxy-(silyl)-propyl-methacrylate (TMSPM), respectively, with which TC, HC1, HC2, and HC3 coatings were elaborated using the immersion technique and polymerized (120 °C for 24 h). The solutions were characterized by FT-IR and TGA, and the coatings by SEM, nanoindentation, AFM, adhesion, and contact angle. The results showed that SiO2 enhanced mechanical (hardness and Young's modulus) and thermal properties of the R-UPR. The coatings adhered perfectly to the substrate, with thicknesses of micrometer units and a flat surface; in addition, hydrophilicity decreased as SiO2 decreased.

Accelerated Aging Ultraviolet of a PET Nonwoven Geotextile and Thermoanalytical Evaluation.

Nonwoven geotextiles are geosynthetic products that are highly susceptible to ultraviolet degradation because light can reach a large area of the material due to its fiber arrangement. Even with additives, which delay the degradation process, material decomposition still occurs, and therefore the product's long-term durability can be affected. In this paper, the mechanical and thermal behavior of a commercial nonwoven polyester geotextile subjected to accelerated ultraviolet aging tests were evaluated. The deterioration was evaluated by comparing the physical properties (mass per unit area, thickness, and tensile strength) and thermal behavior (thermogravimetry-TG, thermomechanical analysis-TMA, and differential scanning calorimetry-DSC) before and after exposure times of 500 h and 1000 h. The results showed that the ultraviolet aging tests induced some damage in the polyester fibers, leading to the deterioration of their tensile strength. For 1000 h of exposure, in which the reduction was larger, scanning electron microscopy (SEM) found some superficial disruption of the fibers, indicative of damage. TG and DSC could not capture the effects of UV radiation on polymer degradation, unlike TMA. This latter technique was effective in showing the differences between specimens before and after UV exposure.

Well-of-the-well (WOW) versus polyester mesh (PM): a comparison of single-embryo culture systems in bovines

Background: Mexico is innovating in the livestock industry through in vitro generation of bovine embryos with technologies such as well-of-the-well (WOW) and polyester mesh (PM) single-embryo culture systems. These techniques allow to maintain embryos in separate areas of a shared culture medium. Objective: To compare the quantity and quality of bovine embryos produced in WOW and PM culture systems versus the conventional (CG) culture system. Methods: In total, 345 embryos fertilized in vitro were evaluated for blastocyst yield in the three culture systems. To count blastocyst cell numbers, 69 embryos in each system were differentially stained for trophectoderm (TE), inner cell mass (ICM), and apoptotic cells. A qPCR gene expression analysis was performed for embryos in all three systems. Results: The WOW, PM and CG systems developed similar amount of blastocysts (41, 35 and 36%, respectively; p>0.05). Blastocysts in all three systems showed adequate amounts of ICM and apoptotic cells. Blastocysts in the PM system showed a greater number of TE cells [63.7 versus 58.6% in the CG system (p0.05). The ATP5B expression was higher in WOW than in PM (p0.05). The TJP3 expression was higher in PM than in WOW and CG (p<0.05). Expression of ID2 and CLDN4 was higher in WOW than in PM and CG (p<0.05). The biplot graphic from Principal Component Analysis (PCA) revealed that CG was located near degenerated embryos, whereas PM was located near arrested embryos, larger ICM and TE, and TJP3 expression. The WOW was located toward blastocysts, morulae, and expression of CLDN4, ID2 and GNAS. Conclusion: Compared with CG, both the PM and WOW systems are good options for culturing single embryos in the bovine model. Moreover, the PCA results suggest that embryos developed in the WOW system have greater capacity for generating blastocysts with increased ability to form TE and ICM layers, which might improve implantation.

Antecedentes: México está innovando en la industria ganadera a través de la generación in vitro de embriones bovinos con tecnologías de cultivo individual como lo son Pozo dentro de Pozo (WOW) y Malla de Poliéster (PM). Estos mantienen los embriones en áreas separadas mientras comparten un mismo medio de cultivo celular. Objetivo: Comparar la cantidad y calidad de embriones bovinos producidos en los sistemas WOW y PM contra el sistema de cultivo convencional en grupo (CG). Métodos: En total se evaluaron 345 embriones fertilizados in vitro para determinar la producción de blastocistos generados en los tres sistemas. Para contar el número de células por blastocisto, 69 embriones en cada sistema se tiñeron diferencialmente para trofectodermo (TE), masa celular interna (ICM) y células apoptóticas. Se realizó un análisis de expresión génica por qPCR de los embriones obtenidos en los tres sistemas. Resultados: Los sistemas WOW, PM y CG desarrollaron similares cantidades de blastocistos (41, 35 y 36%, respectivamente; p>0,05). Los blastocistos en los tres sistemas mostraron cantidades adecuadas de ICM y células apoptóticas. Los blastocistos en el sistema PM mostraron un mayor número de células TE [63,7% versus 58,6% en el sistema CG (p0,05). La expresión de ATP5B fue mayor en WOW que en PM (p<0,05), pero similar a CG (p<0,05). La expresión de TJP3 fue mayor en PM que en WOW y CG (p<0,05). La expresión de ID2 y CLDN4 fue mayor en WOW que en PM y CG (p<0,05). El gráfico de biplot del análisis de componentes principales reveló que CG se encontró cerca de embriones degenerados, mientras que PM se encontró cerca de embriones en arresto, ICM, TE, y TJP3. El WOW se localizó hacia blastocistos, mórulas y la expresión de CLDN4, ID2 y GNAS. Conclusión: En el modelo bovino los sistemas PM y WOW son buenas opciones para cultivar embriones individuales, ya que se obtienen resultados muy similares a los obtenidos con el sistema CG. Además, los resultados de PCA sugieren que los embriones individuales desarrollados en el sistema WOW generan blastocistos con mayor capacidad de formar TE e ICM, lo que podría mejorar su éxito de implantación.

Antecedentes: O México está inovando na indústria pecuária por meio da geração in vitro de embriões bovinos com tecnologias de cultura de embriões individuais, bem como em poço (WOW) e malha de poliéster (PM). Estes mantêm os embriões em áreas separadas, enquanto compartilham o mesmo meio de cultura de células. Objetivo: Comparar a quantidade e a qualidade de embriões bovinos produzidos nos sistemas de cultura WOW e PM com o sistema convencional de cultura em grupo (CG). Métodos: No total, 345 embriões fertilizados in vitro foram avaliados para determinar a produção de blastocistos gerados nos três sistemas. O número de células por blatocisto foi contado, 69 embriões em cada sistema foram diferencialmente corados para trofectoderme (TE), massa celular interna (ICM) e células apoptóticas. Uma análise de expressão gênica qPCR foi realizada para os embriões obtidos nos três sistemas. Resultados: Os sistemas WOW, PM e CG desenvolveram quantidades semelhantes de blastocistos (41, 35 e 36%, respectivamente; p>0,05). Os blastocistos nos três sistemas mostraram quantidades adequadas de ICM e células apoptóticas. Os blastocistos no sistema PM mostraram um número maior de células TE [63,7 versus 58,6% no sistema CG (p0,05). A expressão de ATP5B foi maior no WOW do que no PM (p<0,05), mas semelhante ao GC (p<0,05). A expressão de TJP3 foi maior no PM do que no WOW e CG (p<0,05). A expressão de ID2 e CLDN4 foi maior no WOW do que no PM e CG (p<0,05). O gráfico biplot da análise de componentes principais revelou que CG foi encontrado próximo a embriões degenerados, enquanto PM foi encontrado próximo a embriões presos, ICM, TE e TJP3. WOW foi encontrado para ter blastocistos, mórulas e a expressão de CLDN4, ID2 e GNAS. Conclusão: Em comparação com o CG, os sistemas PM e WOW são boas opções para a cultura de embriões individuais no modelo bovino. Além disso, os resultados da PCA sugerem que embriões individuais desenvolvidos no sistema WOW têm maior capacidade de desenvolver blastocistos com maior capacidade de formar as camadas TE e ICM, o que poderia melhorar seu sucesso de implantação.

Multi-Branched Thoracoabdominal Endovascular Aortic Repair With Branch Access Through a Left Thoracotomy and Descending Thoracic Aortic Conduit: A Novel and Effective Alternative Access.

PURPOSE: To demonstrate an alternative access to perform directional branch catheterization during complex endovascular aortic repair. TECHNIQUE: Urgent endovascular aortic repair was indicated to treat a symptomatic post dissection thoracoabdominal aneurysm with large infrarenal dilatation with an off-the-shelf t-Branch endograft (Cook Medical, Bloomington, IN, USA). Traditional proximal arterial accesses were not suitable due to a previous aortic arch endograft. A novel approach was performed through a left postero-lateral thoracotomy, isolation of the descending thoracic aorta and anastomosed a polyester graft conduit to allow sheaths passage to the thoracoabdominal aorta with subsequently directional branch catheterization. CONCLUSION: The descending thoracic aortic conduit technique is an effective alternative for directional branch catheterization and should be considered whenever traditional proximal arterial accesses are not suitable and other endografts configurations not considered due to anatomic limitations.

Antarctic Polyester Hydrolases Degrade Aliphatic and Aromatic Polyesters at Moderate Temperatures.

Polyethylene terephthalate (PET) is one of the most widely used synthetic plastics in the packaging industry, and consequently has become one of the main components of plastic waste found in the environment. However, several microorganisms have been described to encode enzymes that catalyze the depolymerization of PET. While most known PET hydrolases are thermophilic and require reaction temperatures between 60°C and 70°C for an efficient hydrolysis of PET, a partial hydrolysis of amorphous PET at lower temperatures by the polyester hydrolase IsPETase from the mesophilic bacterium Ideonella sakaiensis has also been reported. We show that polyester hydrolases from the Antarctic bacteria Moraxella sp. strain TA144 (Mors1) and Oleispira antarctica RB-8 (OaCut) were able to hydrolyze the aliphatic polyester polycaprolactone as well as the aromatic polyester PET at a reaction temperature of 25°C. Mors1 caused a weight loss of amorphous PET films and thus constitutes a PET-degrading psychrophilic enzyme. Comparative modeling of Mors1 showed that the amino acid composition of its active site resembled both thermophilic and mesophilic PET hydrolases. Lastly, bioinformatic analysis of Antarctic metagenomic samples demonstrated that members of the Moraxellaceae family carry candidate genes coding for further potential psychrophilic PET hydrolases. IMPORTANCE A myriad of consumer products contains polyethylene terephthalate (PET), a plastic that has accumulated as waste in the environment due to its long-term stability and poor waste management. One promising solution is the enzymatic biodegradation of PET, with most known enzymes only catalyzing this process at high temperatures. Here, we bioinformatically identified and biochemically characterized an enzyme from an Antarctic organism that degrades PET at 25°C with similar efficiency to the few PET-degrading enzymes active at moderate temperatures. Reasoning that Antarctica harbors other PET-degrading enzymes, we analyzed available data from Antarctic metagenomic samples and successfully identified other potential enzymes. Our findings contribute to increasing the repertoire of known PET-degrading enzymes that are currently being considered as biocatalysts for the biological recycling of plastic waste.