Acute respiratory distress syndrome (ARDS) is a clinical entity that acutely affects the lung parenchyma, and is characterized by diffuse alveolar damage and increased pulmonary vascular ...permeability. Currently, computed tomography (CT) is commonly used for classifying and prognosticating ARDS. However, performing this examination in critically ill patients is complex, due to the need to transfer these patients to the CT room. Fortunately, new technologies have been developed that allow the monitoring of patients at the bedside. Electrical impedance tomography (EIT) is a monitoring tool that allows one to evaluate at the bedside the distribution of pulmonary ventilation continuously, in real time, and which has proven to be useful in optimizing mechanical ventilation parameters in critically ill patients. Several clinical applications of EIT have been developed during the last years and the technique has been generating increasing interest among researchers. However, among clinicians, there is still a lack of knowledge regarding the technical principles of EIT and potential applications in ARDS patients. The aim of this review is to present the characteristics, technical concepts, and clinical applications of EIT, which may allow better monitoring of lung function during ARDS.
Bottom‐up tissue engineering is a promising approach for designing modular biomimetic structures that aim to recapitulate the intricate hierarchy and biofunctionality of native human tissues. In ...recent years, this field has seen exciting progress driven by an increasing knowledge of biological systems and their rational deconstruction into key core components. Relevant advances in the bottom‐up assembly of unitary living blocks toward the creation of higher order bioarchitectures based on multicellular‐rich structures or multicomponent cell–biomaterial synergies are described. An up‐to‐date critical overview of long‐term existing and rapidly emerging technologies for integrative bottom‐up tissue engineering is provided, including discussion of their practical challenges and required advances. It is envisioned that a combination of cell–biomaterial constructs with bioadaptable features and biospecific 3D designs will contribute to the development of more robust and functional humanized tissues for therapies and disease models, as well as tools for fundamental biological studies.
The recapitulation of native tissue hierarchy and biofunctionality remains a remarkable challenge. Bottom‐up tissue engineering has arisen as the most promising approach for designing modular biomimetic 3D microtissues that can better display the biofunctionality and biospecific design of living architectures. The most recent advances in integrative bottom‐up engineering of functional microtissues are discussed.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Cultured meat has been proposed as an alternative source of protein to overcome the environmental and ethical problems associated with conventional meat production. However, the lack of consumers' ...acceptance could be a major barrier to the introduction of cultured meat on a large scale. Despite Brazil being one of the countries that consumes the most meat per capita, little is known about Brazilian consumers' preferences for alternative meat. The objective of this study is to identify which attributes influence consumers to possibly replace conventional beef meat with cultured meat in Brazil. An online survey was conducted, and Best-worst scaling methodology was applied to a sample of 225 consumers. The sampling leaned towards educated and employed residents of the southeast region of Brazil, which might not fully represent the Brazilian population. Despite limitations in terms of the sampling demographic, overall, Brazilians appear to be willing to consume cultured meat: 80.9% of the sample would be willing to try it, 61.3% would be willing to eat it regularly, and 56.9% would be willing to eat cultured meat as a replacement for conventionally produced beef. Despite the focus of this study being on attributes of a hypothetical product that is not commercially available, which might pose difficulty to consumers to predict their future consumption behavior, results show that the most important attributes influencing consumers to possibly replace conventional beef meat by cultured meat in Brazil are anticipated risk of zoonotic diseases, anticipated healthiness and anticipated food safety conditions. Attributes related to benefits at a global societal level and intrinsic characteristics of cultured meat were less important.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The aim of this study is to investigate the factors influencing consumer willingness to accept the use of insects to feed poultry, cattle, pigs, and fish. To reach this objective, we conducted an ...online survey with Brazilian consumers. 600 questionnaires were collected. We analyzed data using descriptive statistics and logistic regression models. In general, the use of insects to feed poultry, pigs and cattle was not widely accepted. A more widely acceptance was found for the use of insects to feed fish. The results of logistic regressions models show that positive attitudes are associated with a higher probability of accepting the use of insects to feed poultry, pigs, cattle, and fish. Perceived benefits were associated with a higher likelihood of accepting the use of insects to feed fish. However, perceived benefits were also associated with a lower likelihood of accepting the use of insects to feed poultry. Perceived challenges were associated with a higher likelihood of accepting the use of insects to feed poultry. However, perceived challenges were associated with a lower likelihood of accepting the use of insects to feed pigs.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Electrospun polyvinylpyrrolidone (PVP) nanofibers containing silver, copper, and zinc.•Antimicrobial effect for the bacteria Staphylococcus aureus and Escherichia coli.•Silver strongly reduced ...colony forming units and bacterial viability.•Silver, copper, and zinc led to a significant increase of non-viable cells on mats.
The use of electrospun polyvinylpyrrolidone (PVP) nanofibers containing silver, copper, and zinc nanoparticles was studied to prepare antimicrobial mats using silver and copper nitrates and zinc acetate as precursors. Silver became reduced during electrospinning and formed nanoparticles of several tens of nanometers. Silver nanoparticles and the insoluble forms of copper and zinc were dispersed using low molecular weight PVP as capping agent. High molecular weight PVP formed uniform fibers with a narrow distribution of diameters around 500nm. The fibers were converted into an insoluble network using ultraviolet irradiation crosslinking. The efficiency of metal-loaded mats against the bacteria Escherichia coli and Staphylococcus aureus was tested for different metal loadings by measuring the inhibition of colony forming units and the staining with fluorescent probes for metabolic viability and compromised membranes. The assays included the culture in contact with mats and the direct staining of surface attached microorganisms. The results indicated a strong inhibition for silver-loaded fibers and the absence of significant amounts of viable but non-culturable microorganisms. Copper and zinc-loaded mats also decreased the metabolic activity and cell viability, although in a lesser extent. Metal-loaded fibers allowed the slow release of the soluble forms of the three metals.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
When alveoli collapse the traction forces exerted on their walls by adjacent expanded units may increase and concentrate. These forces may promote its re-expansion at the expense of potentially ...injurious stresses at the interface between the collapsed and the expanded units. We developed an experimental model to test the hypothesis that a local non-lobar atelectasis can act as a stress concentrator, contributing to inflammation and structural alveolar injury in the surrounding healthy lung tissue during mechanical ventilation.
A total of 35 rats were anesthetized, paralyzed and mechanically ventilated. Atelectasis was induced by bronchial blocking: after five minutes of stabilization and pre-oxygenation with FIO2 = 1.0, a silicon cylinder blocker was wedged in the terminal bronchial tree. Afterwards, the animals were randomized between two groups: 1) Tidal volume (VT) = 10 ml/kg and positive end-expiratory pressure (PEEP) = 3 cmH2O (VT10/PEEP3); and 2) VT = 20 ml/kg and PEEP = 0 cmH2O (VT20/zero end-expiratory pressure (ZEEP)). The animals were then ventilated during 180 minutes. Three series of experiments were performed: histological (n = 12); tissue cytokines (n = 12); and micro-computed tomography (microCT; n = 2). An additional six, non-ventilated, healthy animals were used as controls.
Atelectasis was successfully induced in the basal region of the lung of 26 out of 29 animals. The microCT of two animals revealed that the volume of the atelectasis was 0.12 and 0.21 cm3. There were more alveolar disruption and neutrophilic infiltration in the peri-atelectasis region than the corresponding contralateral lung (control) in both groups. Edema was higher in the peri-atelectasis region than the corresponding contralateral lung (control) in the VT20/ZEEP than VT10/PEEP3 group. The volume-to-surface ratio was higher in the peri-atelectasis region than the corresponding contralateral lung (control) in both groups. We did not find statistical difference in tissue interleukin-1β and cytokine-induced neutrophil chemoattractant-1 between regions.
The present findings suggest that a local non-lobar atelectasis acts as a stress concentrator, generating structural alveolar injury and inflammation in the surrounding lung tissue.
Chitosan is a marine-origin polysaccharide obtained from the deacetylation of chitin, the main component of crustaceans' exoskeleton, and the second most abundant in nature. Although this biopolymer ...has received limited attention for several decades right after its discovery, since the new millennium chitosan has emerged owing to its physicochemical, structural and biological properties, multifunctionalities and applications in several sectors. This review aims at providing an overview of chitosan properties, chemical functionalization, and the innovative biomaterials obtained thereof. Firstly, the chemical functionalization of chitosan backbone in the amino and hydroxyl groups will be addressed. Then, the review will focus on the bottom-up strategies to process a wide array of chitosan-based biomaterials. In particular, the preparation of chitosan-based hydrogels, organic-inorganic hybrids, layer-by-layer assemblies, (bio)inks and their use in the biomedical field will be covered aiming to elucidate and inspire the community to keep on exploring the unique features and properties imparted by chitosan to develop advanced biomedical devices. Given the wide body of literature that has appeared in past years, this review is far from being exhaustive. Selected works in the last 10 years will be considered.
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•A new biodegradable poly(ester urethane urea) based on PCL-diol and fish gelatin was synthesized.•Synthesis was confirmed through FTIR, 1H NMR and DSC/TGA.•Electrospun fibrous mats ...and solvent cast films were produced and characterized.•Both fibers and films support fibroblast adhesion and proliferation.
Biodegradable polyurethanes have been studied as scaffolds for tissue engineering due to their adjustable physico-chemical properties. In this work, we synthesized a biodegradable gelatin-based poly(urethane urea) using polycaprolactone-diol, as soft segment, and isophorone diisocyanate and gelatin from cold water fish skin as hard segment. The synthesis was confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance and the influence of the amount of gelatin introduced in the polymer backbone was analyzed by thermal analysis. Gelatin-based poly(urethane urea) electrospun fibrous mats and solvent cast films were then produced and their physico-chemical and biological properties studied. They present an amorphous structure, elastomeric behavior and water contact angles typical of hydrophobic surfaces. Hydrolytic degradation was analyzed in phosphate buffer saline (PBS), lipase and trypsin solutions. No mass changes were detected during 37 days in PBS and trypsin while significant degradation by lipase was observed. Human foetal foreskin fibroblasts were seeded on the fibrous mats and films. Populations were evaluated by colorimetric cell viability assays and morphology by fluorescence imaging. The substrates supported cell adhesion and proliferation. The novel gelatin-based poly(urethane urea) fibrous mats offer attractive physico-chemical and biological properties for soft tissue engineering applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Developing complex supramolecular biomaterials through highly dynamic and reversible noncovalent interactions has attracted great attention from the scientific community aiming key biomedical and ...biotechnological applications, including tissue engineering, regenerative medicine, or drug delivery. In this study, the authors report the fabrication of hybrid supramolecular multilayered biomaterials, comprising high‐molecular‐weight biopolymers and oppositely charged low‐molecular‐weight peptide amphiphiles (PAs), through combination of self‐assembly and electrostatically driven layer‐by‐layer (LbL) assembly approach. Alginate, an anionic polysaccharide, is used to trigger the self‐assembling capability of positively charged PA and formation of 1D nanofiber networks. The LbL technology is further used to fabricate supramolecular multilayered biomaterials by repeating the alternate deposition of both molecules. The fabrication process is monitored by quartz crystal microbalance, revealing that both materials can be successfully combined to conceive stable supramolecular systems. The morphological properties of the systems are studied by advanced microscopy techniques, revealing the nanostructured dimensions and 1D nanofibrous network of the assembly formed by the two molecules. Enhanced C2C12 cell adhesion, proliferation, and differentiation are observed on nanostructures having PA as outermost layer. Such supramolecular biomaterials demonstrate to be innovative matrices for cell culture and hold great potential to be used in the near future as promising biomimetic supramolecular nanoplatforms for practical applications.
The fabrication of hybrid supramolecular nanostructured multilayered biomaterials, comprising high‐molecular‐weight alginate biopolymer and oppositely charged low‐molecular‐weight self‐assembling peptide amphiphile molecule, is reported through the combination of self‐assembly and electrostatically driven layer‐by‐layer assembly approach. Enhanced cell adhesion, proliferation, and differentiation are observed on supramolecular nanostructures having peptide amphiphile as the outermost layer, constituting promising bioinstructive matrices for biomedical and healthcare applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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