Effect of different crosslinking agents on hybrid chitosan/collagen hydrogels for potential tissue engineering applications.

Tissue engineering (TE) demands scaffolds that have the necessary resistance to withstand the mechanical stresses once implanted in our body, as well as excellent biocompatibility. Hydrogels are postulated as interesting materials for this purpose, especially those made from biopolymers. In this study, the microstructure and rheological performance, as well as functional and biological properties of chitosan and collagen hydrogels (CH/CG) crosslinked with different coupling agents, both natural such as d-Fructose (F), genipin (G) and transglutaminase (T) and synthetic, using a combination of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride with N-hydroxysuccinimide (EDC/NHS) will be assessed. FTIR tests were carried out to determine if the proposed crosslinking reactions for each crosslinking agent occurred as expected, obtaining positive results in this aspect. Regarding the characterization of the properties of each system, two main trends were observed, from which it could be established that crosslinking with G and EDC-NHS turned out to be more effective and beneficial than with the other two crosslinking agents, producing significant improvements with respect to the base CH/CG hydrogel. In addition, in vitro tests demonstrated the potential application in TE of these systems, especially for those crosslinked with G, T and EDC-NHS.

Evaluation of rice bran varieties and heat treatment for the development of protein/starch-based bioplastics via injection molding.

Improper management of disposable plastics and resource depletion pose significant environmental challenges, prompting interest in alternatives like bioplastics. These novel materials can be produced from by-products of the agro-food industry, offering solutions and valorizing waste. Rice bran, a substantial by-product of rice processing, is abundant and cost-effective, rich in proteins and starch. These components can be transformed into industrial-grade bioplastics through proper processing. This study evaluates the impact of rice bran varieties and thermal treatment during processing on bioplastic development for injection molding. After defatting and sieving, rice bran was mixed with glycerol and subjected to injection molding at 150 °C. Results indicate that parboiled systems, especially from japonica rice bran, showed high viscoelastic moduli and tensile strength. These systems exhibited a denser structure, resulting in lower water absorption. This research sheds light on the connection between rice bran variety, heat treatment, and the final properties of derived bioplastics. This research contributes significantly to understand the relationship between the variety of rice bran and the impact of heat treatment on the ultimate properties of the derived bioplastics.

Valorization of Honduran Agro-Food Waste to Produce Bioplastics.

The development of biodegradable plastics and eco-friendly biomaterials derived from renewable resources is crucial for reducing environmental damage. Agro-industrial waste and rejected food can be polymerized into bioplastics, offering a sustainable solution. Bioplastics find use in various industries, including for food, cosmetics, and the biomedical sector. This research investigated the fabrication and characterization of bioplastics using three types of Honduran agro-wastes: taro, yucca, and banana. The agro-wastes were stabilized and characterized (physicochemically and thermically). Taro flour presented the highest protein content (around 4.7%) and banana flour showed the highest moisture content (around 2%). Furthermore, bioplastics were produced and characterized (mechanically and functionally). Banana bioplastics had the best mechanical properties, with a Young's modulus around 300 MPa, while taro bioplastics had the highest water-uptake capacity (200%). In general, the results showed the potential of these Honduran agro-wastes for producing bioplastics with different characteristics that could add value to these wastes, promoting the circular economy.

Evaluation of an enhanced recovery after lung surgery (ERALS) program in lung cancer lobectomy: An eight-year experience.

INTRODUCTION: Enhanced recovery after lung surgery (ERALS) protocols have proven useful in reducing postoperative stay (POS) and postoperative complications (POC). We studied the performance of an ERALS program for lung cancer lobectomy in our institution, aiming to identify which factors are associated with a reduction of POC and POS. METHODS: Analytic retrospective observational study conducted in a tertiary care teaching hospital involving patients submitted to lobectomy for lung cancer and included in an ERALS program. Univariable and multivariable analysis were employed to identify factors associated with increased risk of POC and prolonged POS. RESULTS: A total 624 patients were enrolled in the ERALS program. The median POS was 4 days (range 1-63), with 2.9% of ICU postoperative admission. A videothoracoscopic approach was used in 66.6% of cases, and 174 patients (27.9%) experienced at least one POC. Perioperative mortality rate was 0.8% (5 cases). Mobilization to chair in the first 24h after surgery was achieved in 82.5% of cases, with 46.5% of patients achieving ambulation in the first 24h. Absence of mobilization to chair and preoperative FEV1% less than 60% predicted, were identified as independent risk factors for POC, while thoracotomy approach and the presence of POC predicted prolonged POS. CONCLUSIONS: We observed a reduction in ICU admissions and POS contemporaneous with the use of an ERALS program in our institution. We demonstrated that early mobilization and videothoracoscopic approach are modifiable independent predictors of reduced POC and POS, respectively.

Evaluation of an enhanced recovery after lung surgery (ERALS) program in lung cancer lobectomy: An eight-year experience / Evaluación de un programa de rehabilitación multimodal en lobectomía por cáncer de pulmón: experiencia de 8 años

Introduction: Enhanced recovery after lung surgery (ERALS) protocols have proven useful in reducing postoperative stay (POS) and postoperative complications (POC). We studied the performance of an ERALS program for lung cancer lobectomy in our institution, aiming to identify which factors are associated with a reduction of POC and POS. Methods: Analytic retrospective observational study conducted in a tertiary care teaching hospital involving patients submitted to lobectomy for lung cancer and included in an ERALS program. Univariable and multivariable analysis were employed to identify factors associated with increased risk of POC and prolonged POS. Results: A total 624 patients were enrolled in the ERALS program. The median POS was 4 days (range 1–63), with 2.9% of ICU postoperative admission. A videothoracoscopic approach was used in 66.6% of cases, and 174 patients (27.9%) experienced at least one POC. Perioperative mortality rate was 0.8% (5 cases). Mobilization to chair in the first 24h after surgery was achieved in 82.5% of cases, with 46.5% of patients achieving ambulation in the first 24h. Absence of mobilization to chair and preoperative FEV1% less than 60% predicted, were identified as independent risk factors for POC, while thoracotomy approach and the presence of POC predicted prolonged POS. Conclusions: We observed a reduction in ICU admissions and POS contemporaneous with the use of an ERALS program in our institution. We demonstrated that early mobilization and videothoracoscopic approach are modifiable independent predictors of reduced POC and POS, respectively. (AU)

Introducción: Los programas de recuperación intensificada en cirugía de pulmón (por sus siglas en inglés, ERALS) han demostrado ser útiles para reducir la estancia hospitalaria y las complicaciones postoperatorias. Estudiamos los resultados de la aplicación de un programa ERALS para lobectomía por cáncer en nuestro centro con la intención de identificar aquellos factores que se relacionan con la reducción de las complicaciones y la estancia. Métodos: Estudio observacional retrospectivo en pacientes sometidos a lobectomía por cáncer de pulmón e incluidos en un programa ERALS. Se empleó análisis univariable y multivariable para identificar los factores de riesgo de complicaciones y estancia prolongada. Resultados: Un total de 624 pacientes se inscribieron en el programa ERALS. La estancia postoperatoria mediana fue de 4 días (1-63), con una tasa de ingreso en la UCI del 2,9%. El abordaje videotoracoscópico fue empleado en el 66,6% de los casos, y la tasa de complicaciones postoperatorias fue del 27,9%, con una tasa de mortalidad del 0,8% (5 casos). La no movilización en las primeras 24h, y el FEV1% inferior al 60% del previsto, se identificaron como factores de riesgo de complicaciones; mientras que el abordaje mediante toracotomía y la presencia de complicaciones predijeron la estancia prolongada. Conclusiones: Observamos una reducción en la estancia hospitalaria y en los ingresos postoperatorios en la UCI concomitante a la puesta en marcha de un programa ERALS en nuestro centro. La movilización precoz y el abordaje quirúrgico videotoracoscópico demostraron ser predictores independientes y modificables para la reducción de las complicaciones y para la duración de la estancia, respectivamente. (AU)

Accuracy and Comprehensiveness in Recording Information of a Web-Based Application for Preoperative Assessment: A Prospective Observational Study.

PURPOSE: Preanestes@s is a web-based application that includes a smart computer-based self-assessment preoperative questionnaire (PreQuest). Preanestes@s enables remote non-telephonic preoperative assessment via a virtual visit. We aimed to determine if the American Society of Anesthesiologists (ASA) physical status classification assigned by PreQuest and virtual visit is comparable with that assigned by face-to-face assessment, and to determine the accuracy of Preanestes@s in recording complementary preoperative information. DESIGN: Prospective, observational, paired study. METHODS: This study was conducted in a tertiary teaching hospital. A total of 510 adult patients scheduled for surgery were consecutively recruited. Of these, 220 patients were included in the analysis of ASA grade agreement. FINDINGS: PreQuest and virtual visit showed higher predictive value than face-to-face assessment in detecting patients with ASA grades 1 to 2. Face-to-face assessment showed the highest rate of false negatives (ASA 3-4 misclassified as ASA 1-2), with a sensitivity of 44.2% versus 69.8% and 50% for PreQuest and virtual visit, respectively. Virtual visit showed the highest agreement with the ASA grade assigned by a panel of experts (kappa index 0.52, 95% confidence interval 0.15-0.89). PreQuest and virtual visit offered a more comprehensive registry of anthropometric data, more detailed record of chronic diseases condition, and more accurate registry of patients' treatments (virtual visit > PreQuest > face-to-face assessment). CONCLUSIONS: The combined use of PreQuest and virtual visit offers a better performance in assigning the ASA grade for non-complex patients and a more accurate and detailed record of complementary information. This finding suggests the feasibility of Preanestes@ as a tool for preoperative assessment.

What are the determinants of the willingness to share rides in pooled on-demand services?

Simulation studies suggest that pooled on-demand services (also referred to as Demand Responsive Transport, ridesharing, shared ride-hailing or shared ridesourcing services) have the potential to bring large benefits to urban areas while inducing limited time losses for their users. However, in reality, the large majority of users request individual rides (and not pooled rides) in existing on-demand services, leading to increases in motorised vehicle miles travelled. In this study, we investigate to what extent fare discounts, additional travel time, and the (un)willingness to share the ride with (different numbers of) other passengers play a role in the decision of individuals to share rides. To this end, we design a stated preference study targeting Dutch urban individuals. In our research, we (1) disentangle the sharing aspect from related time-cost trade-offs (e.g. detours), (2) investigate preference heterogeneity regarding the studied attributes and identify distinct market segments, and (3) simulate scenarios to understand the impact of the obtained parameters in the breakdown between individual and pooled services. We find that less than one third of respondents have strong preferences against sharing their rides. Also, we find that different market segments vary not only in their values of the willingness to share, but also in how they perceive this willingness to share (per-ride or proportional to the in-vehicle time). Further, the scenario analysis demonstrates that the share of individuals who are willing to share rides depends primarily on the time-cost trade-offs, rather than on the disutility stemming from pooling rides per se.

Rice bran-based bioplastics: Effects of the mixing temperature on starch plastification and final properties.

The agro-food industry produces huge amounts of wastes and by-products with high levels of carbohydrates and proteins, basic food groups that, properly treated, can be employed for the development of bioplastics. These high added-value products represent an alternative to traditional polymers. In this research work, rice bran was mixed with glycerol and water obtaining homogeneous blends which then are processed into bioplastics via injection moulding. The mixing temperature aids starch plastification and thus, affects the properties of the final specimens. In this way, the mechanical characterization revealed improvements for the highest temperature (110 °C) used which, at the same time, exhibited poor physical integrity during water immersion. Although the mechanical properties of the dried system obtained at 80 °C are slightly inferior to those obtained for the non-dried 110 °C system, these specimens are considered more adequate since they exhibited higher physical integrity and, consequently, better operating conditions.

Applied Rheology as Tool for the Assessment of Chitosan Hydrogels for Regenerative Medicine.

The regeneration of soft tissues that connect, support or surround other tissues is of great interest. In this sense, hydrogels have great potential as scaffolds for their regeneration. Among the different raw materials, chitosan stands out for being highly biocompatible, which, together with its biodegradability and structure, makes it a great alternative for the manufacture of hydrogels. Therefore, the aim of this work was to develop and characterize chitosan hydrogels. To this end, the most important parameters of their processing, i.e., agitation time, pH, gelation temperature and concentration of the biopolymer used were rheologically evaluated. The results show that the agitation time does not have a significant influence on hydrogels, whereas a change in pH (from 3.2 to 7) is a key factor for their formation. Furthermore, a low gelation temperature (4 °C) favors the formation of the hydrogel, showing better mechanical properties. Finally, there is a percentage of biopolymer saturation, from which the properties of the hydrogels are not further improved (1.5 wt.%). This work addresses the development of hydrogels with high thermal resistance, which allows their use as scaffolds without damaging their mechanical properties.

Effects of Mould Temperature on Rice Bran-Based Bioplastics Obtained by Injection Moulding.

The high production rate of conventional plastics and their low degradability result in severe environmental problems, such as plastic accumulation and some other related consequences. One alternative to these materials is the production of oil-free bioplastics, based on wastes from the agro-food industry, which are biodegradable. Not only is rice bran an abundant and non-expensive waste, but it is also attractive due to its high protein and starch content, which can be used as macromolecules for bioplastic production. The objective of this work was to develop rice-bran-based bioplastics by injection moulding. For this purpose, this raw material was mixed with a plasticizer (glycerol), analysing the effect of three mould temperatures (100, 130 and 150 °C) on the mechanical and microstructural properties and water absorption capacity of the final matrices. The obtained results show that rice bran is a suitable raw material for the development of bioplastics whose properties are strongly influenced by the processing conditions. Thus, higher temperatures produce stiffer and more resistant materials (Young's modulus improves from 12 ± 7 MPa to 23 ± 6 and 33 ± 6 MPa when the temperature increases from 100 to 130 and 150 °C, respectively); however, these materials are highly compact and, consequently, their water absorption capacity diminishes. On the other hand, although lower mould temperatures lead to materials with lower mechanical properties, they exhibit a less compact structure, resulting in enhanced water absorption capacity.

Rice Bran-Based Bioplastics: Effects of Biopolymer Fractions on Their Mechanical, Functional and Microstructural Properties.

Rice bran is an underutilized by-product of rice production, containing proteins, lipids and carbohydrates (mainly starches). Proteins and starches have been previously used to produce rice bran-based bioplastics, providing a high-added-value by-product, while contributing to the development of biobased, biodegradable bioplastics. However, rice bran contains oil (18-22%), which can have a detrimental effect on bioplastic properties. Its extraction could be convenient, since rice bran oil is becoming increasingly attractive due to its variety of applications in the food, pharmacy and cosmetic industries. In this way, the aim of this work was to analyze the effect of the different components of rice bran on the final properties of the bioplastics. Rice bran refining was carried out by extracting the oil and fiber fractions, and the effects of these two procedures on the final properties were addressed with mechanical, functional and microstructural measures. Results revealed that defatted rice bran produced bioplastics with higher viscoelastic moduli and better tensile behavior while decreasing the water uptake capacity and the soluble matter loss of the samples. However, no significant improvements were observed for systems produced from fiber-free rice bran. The microstructures observed in the SEM micrographs matched the obtained results, supporting the conclusions drawn.