Action of AA9 lytic polysaccharide monooxygenase enzymes on different cellulose allomorphs.

Lytic polysaccharide monooxygenase (LPMO)-catalyzed oxidative processes play a major role in natural biomass conversion. Despite their oxidative cleavage at the surface of polysaccharides, understanding of their mode of action, and the impact of structural patterns of the cellulose fiber on LPMO activity is still not fully understood. In this work, we investigated the action of two different LPMOs from Podospora anserina on celluloses showing different structural patterns. For this purpose, we prepared cellulose II and cellulose III allomorphs from cellulose I cotton linters, as well as amorphous cellulose. LPMO action was monitored in terms of surface morphology, molar mass changes and monosaccharide profile. Both PaLPMO9E and PaLPMO9H were active on the different cellulose allomorphs (I, II and III), and on amorphous cellulose (PASC) whereas they displayed a different behavior, with a higher molar mass decrease observed for cellulose I. Overall, the pretreatment with LPMO enzymes clearly increased the accessibility of all types of cellulose, which was quantified by the higher carboxylate content after carboxymethylation reaction on LPMO-pretreated celluloses. This work gives more insight into the action of LPMOs as a tool for deconstructing lignocellulosic biomass to obtain new bio-based building blocks.

Xyloglucan-Cellulose Nanocrystals Mixtures: A Case Study of Nanocolloidal Hydrogels and Levers for Tuning Functional Properties.

The development of fully biobased hydrogels obtained by simple routes and in the absence of toxic or environmentally harmful reagents is a major challenge in meeting new societal demands. In this work, we discuss the development of hydrogels made from cellulose nanocrystals (CNCs) and xyloglucan (XG), two non-toxic, renewable, and biobased components. We present three strategies to fine-tune the functional properties. The first one consists in varying the XG/CNC ratio that leads to the modulation of the mechanical properties of hydrogels as well as a better comprehension of the gel mechanism formation. The second relies on tuning the XG chains' interaction by enzymatic modification to achieve thermoresponsive systems. Finally, the third one is based on the increase in the hydrogel solid content by osmotic concentration. The high-solid-content gels were found to have very high mechanical properties and self-healing properties that can be used for molding materials. Overall, these approaches are a case study of potential modifications and properties offered by biobased nanocolloidal hydrogels.

Flexoelectric and piezoelectric effects in micro- and nanocellulose films.

In this work, we evaluated the flexoelectric and piezoelectric contributions to the overall macroscopic polarization in cellulose films. To this end, the flexoelectric µ31 and transverse effective piezoelectric e31,f coefficients of cellulose films were determined using cantilever beam bending. The experiments were based on theoretical developments allowing to separate the flexoelectric from the piezoelectric contribution, represented by an effective flexoelectric coefficient, µeff, depending on both e31,f and µ31. Five free-standing and stainless steel/cellulose bilayer films were prepared from cellulose showing different morphologies and surface charge degrees: two almost neutral cellulose microfibers (CMF) and three (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose micro- (TCMF) and nanofibers (TCNF) bearing negative charged groups on the surface. The dielectric properties of the films indicated a low dielectric constant for unmodified CMF, and a huge increase for TEMPO-oxidized samples, which were up to 9 times higher than poly(vinylidene fluoride)-based polymers. TEMPO-oxidized cellulose films exhibited the largest flexoelectric coefficients (almost 7 times higher than those of synthetic polymer dielectrics), which evidenced that the presence of polar groups and surface charge boosted both flexoelectricity and piezoelectricity in unpoled cellulose films. These findings pave the way towards sustainable cellulose-based curvature sensors with large effective flexoelectric coefficients, without the need of preliminary energy consuming poling step.

Optimized Lytic Polysaccharide Monooxygenase Action Increases Fiber Accessibility and Fibrillation by Releasing Tension Stress in Cellulose Cotton Fibers.

Lytic polysaccharide monooxygenase (LPMO) enzymes have recently shaken up our knowledge of the enzymatic degradation of biopolymers and cellulose in particular. This unique class of metalloenzymes cleaves cellulose and other recalcitrant polysaccharides using an oxidative mechanism. Despite their potential in biomass saccharification and cellulose fibrillation, the detailed mode of action of LPMOs at the surface of cellulose fibers still remains poorly understood and highly challenging to investigate. In this study, we first determined the optimal parameters (temperature, pH, enzyme concentration, and pulp consistency) of LPMO action on the cellulose fibers by analyzing the changes in molar mass distribution of solubilized fibers using high performance size exclusion chromatography (HPSEC). Using an experimental design approach with a fungal LPMO from the AA9 family (PaLPMO9H) and cotton fibers, we revealed a maximum decrease in molar mass at 26.6 °C and pH 5.5, with 1.6% w/w enzyme loading in dilute cellulose dispersions (100 mg of cellulose at 0.5% w/v). These optimal conditions were used to further investigate the effect of PaLPMO9H on the cellulosic fiber structure. Direct visualization of the fiber surface by scanning electron microscopy (SEM) revealed that PaLPMO9H created cracks on the cellulose surface while it attacked tension regions that triggered the rearrangement of cellulose chains. Solid-state NMR indicated that PaLPMO9H increased the lateral fibril dimension and created novel accessible surfaces. This study confirms the LPMO-driven disruption of cellulose fibers and extends our knowledge of the mechanism underlying such modifications. We hypothesize that the oxidative cleavage at the surface of the fibers releases the tension stress with loosening of the fiber structure and peeling of the surface, thereby increasing the accessibility and facilitating fibrillation.

Caracterización de adolescentes lesionados por armas blancas en región tóraco-abdominal / Adolescents' characterization injured by steels in tóraco-abdominal region

Introducción: El trauma intencional por arma blanca, que ocasiona lesiones potencialmente fatales, constituye una de las causas de atención médica frecuente en el Servicio de Urgencias. Objetivo: Caracterizar a adolescentes con lesiones por armas blancas en región tóraco-abdominal. Métodos: Se realizó un estudio observacional, descriptivo, de corte transversal en 94 pacientes con lesiones tóraco-abdominales por arma blanca ingresados en el Hospital Pediátrico Juan Manuel Márquez en el período comprendido desde enero del 2016 hasta diciembre del 2020. Las variables estudiadas fueron: edad, sexo, tipo de heridas y localización, lesiones ocasionadas, procedimientos quirúrgicos realizados, complicaciones y casuística según los años estudiados. Resultados: El sexo masculino fue el más frecuente (92,6 por ciento) y las edades entre 15 y 18 años (87,2 por ciento). Predominaron las heridas de tipo no penetrantes (60,7 por ciento) y la localización torácica (59,8 por ciento). En las lesiones penetrantes predominó el neumotórax abierto (31 por ciento). Los procedimientos quirúrgicos más realizados fueron la sutura de herida traumática (100 por ciento) y la pleurostomía (44,8 por ciento). Entre las complicaciones presentadas prevalecieron la neumonía (35,2 por ciento) y la infección de la herida traumática (17,6 por ciento). El 2019 fue el año con mayor número de casos (25,5 por ciento). Conclusiones: Los adolescentes con lesiones tóraco-abdominales por arma blanca se caracterizan, en general, por ser varones entre 15 y 18 años. Las heridas de tipo no penetrante en tórax constituyen la lesión fundamental y la sutura de heridas es el procedimiento quirúrgico más empleado. La complicación más frecuente es la neumonía(AU)

Introduction: Intentional stab wound trauma, which causes potentially fatal injuries, is one of the causes for frequent medical attention in the emergency department. Objective: To characterize adolescents with stab wounds in the thoracoabdominal region. Methods: An observational, descriptive and cross-sectional study was conducted in 94 patients with thoracoabdominal stab wounds admitted to Hospital Pediátrico Juan Manuel Márquez from January 2016 to December 2020. The variables studied were age, sex, wound type and location, caused injuries, performed surgical procedures, complications and casuistry according to the studied years. Results: The male sex was the most frequent (92.6 percent), together with ages between 15 and 18 years (87.2 percent). Nonpenetrating injuries (60.7 percent) and the thoracic location (59.8 percent) predominated. Among penetrating injuries, open pneumothorax (31 percent) dominated. The most frequently performed surgical procedures were traumatic wound suturing (100 percent) and pleurostomy (44.8 percent). Among the complications, pneumonia (35.2 percent) and traumatic wound infection (17.6 percent) prevailed. 2019 was the year with the highest number of cases (25.5 percent). Conclusions: Adolescents with thoracoabdominal stab wounds were generally characterized as males at ages between 15 and 18 years. Nonpenetrating thoracic wounds are the main injuries and wound suturing is the most frequently used surgical procedure. The most frequent complication is pneumonia(AU)

Unraveling the control of reversibility for actuators based on cellulose nanofibers.

In this work, we have prepared cellulose-based actuators taking advantage of the pH-sensitive solubility of chitosan (CH) and the mechanical strength of CNFs. Bilayer films were prepared by vacuum filtration inspired by plant structures that exhibit reversible deformation under pH changes. The presence of CH in one of the layers led to asymmetric swelling at low pH, thanks to the electrostatic repulsion between charged amino groups of CH, and the subsequent twisting with the CH layer on the outside. Reversibility was achieved by substituting pristine CNFs with carboxymethylated CNFs (CMCNFs), that are charged at high pH and thus competed with the effects of amino groups. Swelling and mechanical properties of layers under pH changes were studied by gravimetry and dynamic mechanical analysis (DMA) to quantify the contribution of chitosan and the modified CNFs on the reversibility control. This work evidenced the key role of surface charge and layer stiffness to achieve reversibility. Bending was triggered by the different water uptake of each layer, and shape recovery was achieved when the shrunk layer shower higher rigidity than the swollen layer.

Xyloglucan-cellulose nanocrystal-chitosan double network hydrogels for soft actuators.

Hydrogels are materials consisting in a three-dimensional hydrophilic polymer network swollen by a large amount of water. An efficient strategy to elaborate hydrogels consists in establishing double polymer networks in order to achieve high strengthening effect associated with other properties such as transparency or tailored swelling capacities. In this work, we prepared cellulose nanocrystals (CNC)-based hydrogels with double network architecture. The first network, formed by CNC and xyloglucan (XG), takes advantage of entropic adsorption of XG on the CNC surface while the second network relies on electrostatic interactions between cationic Chitosan (Chi) and anionic CNC. Hydrogels with different compositions were successfully prepared. Their rheological properties, stability and swelling capacities in acidic and alkaline solutions were evaluated. Internal organizations of hydrogels were investigated by fluorescence microscopy after polymer labelling and polarized optical microscopy (POM). Finally, hydrogels demonstrated excellent mechanical properties and tuneable swelling capacities that can be leveraged for the implementation of bilayer actuators. Therefore, we further prepared films composed of two hydrogels layers, each one containing a different XG/CNC ratio. Bilayered films bended in water due to the asymmetric swelling of layers and the extent of bending can be modulated by the XG/CNC ratio.

Divergent growth of poly(amidoamine) dendrimer-like branched polymers at the reducing end of cellulose nanocrystals.

This paper presents the growth of dendritic polymers at the reducing ends of cellulose nanocrystals by the "grafting from" approach. We took advantage of the chemically differentiated ends of cellulose nanocrystals to specifically synthesize dendrimers at their reducing end by the divergent approach. We used acid-amine coupling reactions in aqueous media to synthesize the carboxylic acid- or amine-terminated poly(amidoamine) dendrimers. The growth of dendrimer generations was monitored by UV and FTIR spectroscopies, and we successfully introduced up to 4 generations. The dendrimer growth at reducing ends was demonstrated by the nanocrystal adsorption driven by the peripheral amino groups onto gold surfaces. Hence, the results from quartz crystal microbalance with dissipation (QCM-D) pointed to a rather upright orientation of the dendrimer-modified cellulose nanocrystals. As the generation increased, the adsorbed layers appeared to be more flexible, which demonstrated that the functionality at the reducing end can successfully tune the properties of cellulose nanocrystals.

Guía práctica del traumatismo abdominal en la edad pediátrica

RESUMEN El traumatismo abdominal en la edad pediátrica se considera la segunda causa de muerte después del trauma craneoencefálico. Requiere para su diagnóstico un alto índice de sospecha y su riesgo vital está condicionado por la hemorragia y la peritonitis. Con el propósito de estandarizar en una guía la conducta en Cuba en el traumatismo abdominal pediátrico, se realiza una revisión bibliográfica sobre el tema y el estudio de diferentes casuísticas del hospital pediátrico "Juan Manuel Márquez", que es centro provincial de politrauma infantil de La Habana; la guía se aprueba por consenso en la Sociedad Cubana de Cirugía Pediátrica. Las causas más frecuentes de traumatismo abdominal son: en el niño mayor los accidentes de tránsito y en el niño menor las caídas de altura. En la anamnesis es importante la cinemática del trauma y la superficie de impacto. El examen físico debe ser evolutivo y en la evaluación inicial debe identificarse el riesgo vital. En el diagnóstico por imágenes se considera esencial la tomografía contrastada la que en nuestro centro se reserva para casos con dudas diagnósticas y de evolución no satisfactoria, la ecografía tiene gran utilidad. Se prioriza el tratamiento no quirúrgico en el trauma cerrado con ruptura de víscera maciza, siempre que exista estabilidad hemodinámica. Actualmente la cirugía de control de daños ha demostrado mejorar la sobrevida en pacientes con lesiones abdominales complejas y exanguinantes.

ABSTRACT Abdominal trauma in pediatric age is considered the second leading cause of death after traumatic brain injury. It requires for its diagnosis a high index of suspicion and its vital risk is conditioned by hemorrhage and peritonitis. With the purpose of standardizing in a guide the behavior in Cuba of pediatric abdominal trauma, a bibliographic review is carried out on the subject and the study of different casuistries of "Juan Manuel Márquez" Pediatric Hospital, which functions in turn as a provincial center of children's polytrauma of Havana; the guide is approved by consensus in the Cuban Society of Pediatric Surgery. The most frequent causes of abdominal trauma are: in the older children, traffic accidents and in the younger children falls from heights. In the anamnesis, the kinematics of the trauma and the impact surface are important. The physical examination should be evolutionary and the initial assessment should identify the life risk. In the diagnosis by images is considered essential the contrasted tomography which in our center is reserved for cases with diagnostic doubts and unsatisfactory evolution; ultrasound is very useful. Non-surgical treatment is prioritized in closed trauma with solid viscera rupture, provided that hemodynamic stability exists. Currently, damage control surgery has been shown to improve survival in patients with complex and exanguinating abdominal injuries.

Engineered Multilayer Microcapsules Based on Polysaccharides Nanomaterials.

The preparation of microcapsules composed by natural materials have received great attention, as they represent promising systems for the fabrication of micro-containers for controlled loading and release of active compounds, and for other applications. Using polysaccharides as the main materials is receiving increasing interest, as they constitute the main components of the plant cell wall, which represent an ideal platform to mimic for creating biocompatible systems with specific responsive properties. Several researchers have recently described methods for the preparation of microcapsules with various sizes and properties using cell wall polysaccharide nanomaterials. Researchers have focused mostly in using cellulose nanomaterials as structural components in a bio-mimetic approach, as cellulose constitutes the main structural component of the plant cell wall. In this review, we describe the microcapsules systems presented in the literature, focusing on the works where polysaccharide nanomaterials were used as the main structural components. We present the methods and the principles behind the preparation of these systems, and the interactions involved in stabilizing the structures. We show the specific and stimuli-responsive properties of the reported microcapsules, and we describe how these characteristics can be exploited for specific applications.

Asymmetric modification of cellulose nanocrystals with PAMAM dendrimers for the preparation of pH-responsive hairy surfaces.

In this work, we present a straightforward method to attach a globular dendrimer at the reducing end of cellulose nanocrystals obtained from tunicates (t-CNC). We investigated the first four generations of poly(amidoamine) dendrimers (PAMAMs G0 to G3) to obtain hybrid t-CNCs. The aggregation behavior of hybrid t-CNCs was studied by dynamic light scattering (DLS) and scanning transmission electron microscopy (STEM); and interactions of these asymmetric nanoparticles with gold surface were elucidated using quartz crystal microbalance with dissipation (QCM-D) and surface plasmon resonance (SPR). Hybrid t-CNCs formed hairy layers onto gold surface combining the properties of rigid rod-like nanocrystals with globular and flexible PAMAM dendrimers. Moreover, the presence of amino groups provided pH-responsive properties to hybrid t-CNCs, and QCM-D results revealed reversible swelling/deswelling behavior. Thereby, we achieved to synthesize tree-shaped functional bio-based materials that adsorbed on gold and formed pH-responsive hairy surfaces.

pH-Responsive Properties of Asymmetric Nanopapers of Nanofibrillated Cellulose.

Inspired by plant movements driven by the arrangement of cellulose, we have fabricated nanopapers of nanofibrillated cellulose (NFC) showing actuation under pH changes. Bending was achieved by a concentration gradient of charged groups along the film thickness. Hence, the resulting nanopapers contained higher concentration of charged groups on one side of the film than on the opposite side, so that pH changes resulted in charge-dependent asymmetric deprotonation of the two layers. Electrostatic repulsions separate the nanofibers in the nanopaper, thus facilitating an asymmetric swelling and the subsequent expanding that results in bending. Nanofibrillated cellulose was modified by 2,2,6,6-tetramethylpiperidin-1-yl)oxyl radical (TEMPO) oxidation at two reaction times to get different surface concentrations of carboxylic acid groups. TEMPO-oxidized NFC was further chemically transformed into amine-modified NFC by amidation. The formation of graded nanopapers was accomplished by successive filtration of NFC dispersions with varying charge nature and/or concentration. The extent of bending was controlled by the charge concentration and the nanopaper thickness. The direction of bending was tuned by the layer composition (carboxylic acid or amine groups). In all cases, a steady-state was achieved within less than 25 s. This work opens new routes for the use of cellulosic materials as actuators.

Meaning of xylan acetylation on xylan-cellulose interactions: A quartz crystal microbalance with dissipation (QCM-D) and molecular dynamic study.

In plant cell walls, xylan chains present various substituents including acetate groups. The influence of the acetyl substitution on the organization of xylan-cellulose complexes remains poorly understood. This work combines in vitro and in silico approaches to decipher the functional role of acetyl groups on the xylan/cellulose interaction. Acetylated xylans were extracted from apple pomace with dimethyl sulfoxide-lithium chloride (DMSO-LiCl) and deacetylated using a mild alkali treatment. The adsorption behavior of acetylated and deacetylated xylan fractions was investigated using quartz crystal microbalance with dissipation (QCM-D) and molecular dynamics. Acetylated xylans form a dense and poorly hydrated and rigid layer on cellulose with xylan chains that have two residues per helical turn conformation, whereas the deacetylated fraction forms a swollen and more viscous layer in which only the xylan chains in direct contact with the cellulose surface have two residues per helical turn conformation. The other chains have three residues per turn conformation.

Influence of the carbohydrate-binding module on the activity of a fungal AA9 lytic polysaccharide monooxygenase on cellulosic substrates.

BACKGROUND: Cellulose-active lytic polysaccharide monooxygenases (LPMOs) secreted by filamentous fungi play a key role in the degradation of recalcitrant lignocellulosic biomass. They can occur as multidomain proteins fused to a carbohydrate-binding module (CBM). From a biotech perspective, LPMOs are promising innovative tools for producing nanocelluloses and biofuels, but their direct action on cellulosic substrates is not fully understood. RESULTS: In this study, we probed the role of the CBM from family 1 (CBM1) appended to the LPMO9H from Podospora anserina (PaLPMO9H) using model cellulosic substrates. Deletion of the CBM1 weakened the binding to cellulose nanofibrils, amorphous and crystalline cellulose. Although the release of soluble sugars from cellulose was drastically reduced under standard conditions, the truncated LPMO retained some activity on soluble oligosaccharides. The cellulolytic action of the truncated LPMO was demonstrated using synergy experiments with a cellobiohydrolase (CBH). The truncated LPMO was still able to improve the efficiency of the CBH on cellulose nanofibrils in the same range as the full-length LPMO. Increasing the substrate concentration enhanced the performance of PaLPMO9H without CBM in terms of product release. Interestingly, removing the CBM also altered the regioselectivity of PaLPMO9H, significantly increasing cleavage at the C1 position. Analysis of the insoluble fraction of cellulosic substrates evaluated by optical and atomic force microscopy confirmed that the CBM1 module was not strictly required to promote disruption of the cellulose network. CONCLUSIONS: Absence of the CBM1 does not preclude the activity of the LPMO on cellulose but its presence has an important role in driving the enzyme to the substrate and releasing more soluble sugars (both oxidized and non-oxidized), thus facilitating the detection of LPMO activity at low substrate concentration. These results provide insights into the mechanism of action of fungal LPMOs on cellulose to produce nanocelluloses and biofuels.

Lytic polysaccharide monooxygenases (LPMOs) facilitate cellulose nanofibrils production.

BACKGROUND: Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that cleave polysaccharides through an oxidative mechanism. These enzymes are major contributors to the recycling of carbon in nature and are currently used in the biorefinery industry. LPMOs are commonly used in synergy with cellulases to enhance biomass deconstruction. However, there are few examples of the use of monocomponent LPMOs as a tool for cellulose fibrillation. In this work, we took advantage of the LPMO action to facilitate disruption of wood cellulose fibers as a strategy to produce nanofibrillated cellulose (NFC). RESULTS: The fungal LPMO from AA9 family (PaLPMO9E) was used in this study as it displays high specificity toward cellulose and its recombinant production in bioreactor is easily upscalable. The treatment of birchwood fibers with PaLPMO9E resulted in the release of a mixture of C1-oxidized oligosaccharides without any apparent modification in fiber morphology and dimensions. The subsequent mechanical shearing disintegrated the LPMO-pretreated samples yielding nanoscale cellulose elements. Their gel-like aspect and nanometric dimensions demonstrated that LPMOs disrupt the cellulose structure and facilitate the production of NFC. CONCLUSIONS: This study demonstrates the potential use of LPMOs as a pretreatment in the NFC production process. LPMOs weaken fiber cohesion and facilitate fiber disruption while maintaining the crystallinity of cellulose.

Isolated pulmonary interstitial glycogenosis associated with alveolar growth abnormalities: A long-term follow-up study.

INTRODUCTION: Pulmonary interstitial glycogenosis (PIG) is a rare infant interstitial lung disease characterized by an increase in the number of interstitial mesenchymal cells, presenting as enhanced cytoplasmic glycogen, and is considered to represent the expression of an underlying lung development disorder. METHODS: This study describes the clinical, radiological, and functional characteristics and long-term outcomes (median 12 years) of nine infants diagnosed with isolated PIG associated with alveolar simplification in the absence of other diseases. RESULTS: All patients presented with tachypnea. Additionally, seven patients had breathing difficulties and hypoxemia. Abnormalities in chest-computerized tomography (CT) with a pattern of ground-glass opacity, septal thickening, and air trapping were observed in all individuals, with images suggesting abnormal alveolar growth (parenchymal bands and architectural distortion). All lung biopsies showed alveolar simplification associated with an increased number of interstitial cells, which appeared as accumulated cytoplasmic glycogen. In the follow-up, all patients were asymptomatic. The respiratory function test was normal in only two patients. Five children showed an obstructive pattern, and two children showed a restrictive pattern. Chest-CT, performed after an average of 6.5 years since the initial investigation, revealed a partial improvement of the ground-glass opacity pattern; however, relevant alterations persisted. CONCLUSION: Although the patients with PIG in the absence of other associated pathologies had a good clinical outcome, significant radiographic alterations and sequelae in lung function were still observed after a median follow-up of 12 years, suggesting that PIG is a marker of some other persistent abnormalities in lung growth, which have effects beyond the symptomatic period.

Guía para la enseñanza del apoyo vital pediátrico y neonatal. Consenso para el proyecto de formación e investigación en apoyo vital. Cienfuegos, 2018 / Guideline for pediatric and neonatal life support. Consensus for the project of training and research in life support. Cienfuegos, 2018

Fundamento: La parada cardiorespiratoria en el niño es considerada un problema de salud. El determinante más importante para la supervivencia es la presencia del individuo entrenado para efectuar las maniobras de reanimación cardiopulmocerebral. En el marco del proyecto Formación e investigación en apoyo vital en emergencias y desastres, la actualización de las guías para la enseñanza del apoyo vital pediátrico y neonatal puede contribuir al éxito de la resucitación y sobrevida con calidad.Objetivo: actualizar las guías y estrategia docente para la enseñanza del apoyo vital pediátrico y neonatal.Métodos: se realizó un taller nacional con diez expertos y tres informantes clave, los días 10 y 11 de julio del 2018 en Cienfuegos. Se utilizaron las técnicas de tormenta de ideas y grupo nominal, y se aplicó un cuestionario semiestructurado con revisión documental previa.Desarrollo: se conciliaron los objetivos, aspectos didácticos, estrategia docente, contenidos, alcance y habilidades a desarrollar para la enseñanza del apoyo vital pediátrico y neonatal. Se definió la estructura de un curso prototipo para la enseñanza del tema y las principales consideraciones para su ejecución.Conclusión: las propuestas académicas para el curso Apoyo vital avanzado pediátrico y neonatal permiten el abordaje de la enseñanza en la atención del paciente pediátrico en situaciones de emergencia por el personal médico de asistencia.

Foundation: cardio-respiratory failure in the child is considered a Health problem. The most important determinant for survival is the presence of a trained individual to performer cardio-pulmonary-cerebral resuscitation. In the framework of the project Training and research for life support in Emergencies and disasters, updating guidelines for teaching pediatric and neonatal life support may contribute to resuscitation success and quality survival.Objective: to update the guidelines and strategies for teaching pediatric and neonatal life support.Method: a National Workshop with ten experts and three key informers, during the 10th and 11th of July 2018 in Cienfuegos. Brain storming and nominal group were used as techniques and it was applied a semi-structured questionnaire with previous documentary review.Development: objectives, didactic aspects, teaching strategy, contents, scope, and skills to develop for teaching pediatric and neonatal life support. It was defined the structure a model course for teaching the topic and the main considerations for its execution.Conclusion: academic proposals for the course Advanced pediatric and neonatal life support allow approaching the pediatric patient in emergency situations by the assisting medical personnel.

Lytic xylan oxidases from wood-decay fungi unlock biomass degradation.

Wood biomass is the most abundant feedstock envisioned for the development of modern biorefineries. However, the cost-effective conversion of this form of biomass into commodity products is limited by its resistance to enzymatic degradation. Here we describe a new family of fungal lytic polysaccharide monooxygenases (LPMOs) prevalent among white-rot and brown-rot basidiomycetes that is active on xylans-a recalcitrant polysaccharide abundant in wood biomass. Two AA14 LPMO members from the white-rot fungus Pycnoporus coccineus substantially increase the efficiency of wood saccharification through oxidative cleavage of highly refractory xylan-coated cellulose fibers. The discovery of this unique enzyme activity advances our knowledge on the degradation of woody biomass in nature and offers an innovative solution for improving enzyme cocktails for biorefinery applications.

Star-like Supramolecular Complexes of Reducing-End-Functionalized Cellulose Nanocrystals.

In this work, we take advantage of the parallel organization of cellulose chains in cellulose I yielding an inherent chemical asymmetry of cellulose nanocrystals, i.e., reducing vs nonreducing end, to selectively modify only one end of these rigid rodlike crystals to be used as a linking point for the formation of supramolecular structures. We have prepared biotin-functionalized tunicate cellulose nanocrystals at the reducing end capable of forming new complex supramolecular hierarchies by the addition of the protein streptavidin. Biotin-streptavidin coupling was chosen because streptavidin has a multivalency of four and the biotin-streptavidin bond is known to be highly selective and stable. Hence, streptavidin molecules would link up to four cellulose nanocrystals through their biotin-modified reducing end. Two biotin derivatives were studied, consisting of an anchoring group, i.e., amine or hydrazine; the biotin moiety; and the linker between them. Results show that the length of the linker significantly affects the bond between the biotinylated cellulose nanocrystals and streptavidin, and a certain chain length is necessary for the supramolecular assembly of several cellulose nanocrystals by streptavidin.

The yeast Geotrichum candidum encodes functional lytic polysaccharide monooxygenases.

BACKGROUND: Lytic polysaccharide monooxygenases (LPMOs) are a class of powerful oxidative enzymes that have revolutionized our understanding of lignocellulose degradation. Fungal LPMOs of the AA9 family target cellulose and hemicelluloses. AA9 LPMO-coding genes have been identified across a wide range of fungal saprotrophs (Ascomycotina, Basidiomycotina, etc.), but so far they have not been found in more basal lineages. Recent genome analysis of the yeast Geotrichum candidum (Saccharomycotina) revealed the presence of several LPMO genes, which belong to the AA9 family. RESULTS: In this study, three AA9 LPMOs from G. candidum were successfully produced and biochemically characterized. The use of native signal peptides was well suited to ensure correct processing and high recombinant production of GcLPMO9A, GcLPMO9B, and GcLPMO9C in Pichia pastoris. We show that GcLPMO9A and GcLPMO9B were both active on cellulose and xyloglucan, releasing a mixture of soluble C1- and C4-oxidized oligosaccharides from cellulose. All three enzymes disrupted cellulose fibers and significantly improved the saccharification of pretreated lignocellulosic biomass upon addition to a commercial cellulase cocktail. CONCLUSIONS: The unique enzymatic arsenal of G. candidum compared to other yeasts could be beneficial for plant cell wall decomposition in a saprophytic or pathogenic context. From a biotechnological point of view, G. candidum LPMOs are promising candidates to further enhance enzyme cocktails used in biorefineries such as consolidated bioprocessing.