Green Pathways for the Enzymatic Synthesis of Furan-Based Polyesters and Polyamides

The attention towards the utilization of sustainable feedstocks for polymer synthesis has grown exponentially in recent years. One of the spotlighted monomers derived from renewable resources is 2,5-furandicarboxylic acid (FDCA), one of the most promising bio-based monomers, due to its resemblance to petroleum-based terephthalic acid. Very interesting synthetic routes using this monomer have been reported in the last two decades. Combining the use of bio-based monomers and non-toxic chemicals via enzymatic polymerizations can lead to a robust and favorable approach towards a greener technology of bio-based polymer production. In this chapter, a brief introduction to FDCA-based monomers and enzymatic polymerizations is given, particularly focusing on furan-based polymers and their polymerization. In addition, an outline of the recent developments in the field of enzymatic polymerizations is discussed. </p

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Biodiversity recovery of Neotropical secondary forests

Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes. Copyright © 2019 The Authors, some rights reserved

First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way

We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric array of eight telescopes operating at a wavelength of lambda = 1.3 mm. The EHT data resolve a compact emission region with intrahour variability. A variety of imaging and modeling analyses all support an image that is dominated by a bright, thick ring with a diameter of 51.8 +/- 2.3 mu as (68% credible interval). The ring has modest azimuthal brightness asymmetry and a comparatively dim interior. Using a large suite of numerical simulations, we demonstrate that the EHT images of Sgr A* are consistent with the expected appearance of a Kerr black hole with mass similar to 4 x 10(6) M (circle dot), which is inferred to exist at this location based on previous infrared observations of individual stellar orbits, as well as maser proper-motion studies. Our model comparisons disfavor scenarios where the black hole is viewed at high inclination (i > 50 degrees), as well as nonspinning black holes and those with retrograde accretion disks. Our results provide direct evidence for the presence of a supermassive black hole at the center of the Milky Way, and for the first time we connect the predictions from dynamical measurements of stellar orbits on scales of 10(3)-10(5) gravitational radii to event-horizon-scale images and variability. Furthermore, a comparison with the EHT results for the supermassive black hole M87* shows consistency with the predictions of general relativity spanning over three orders of magnitude in central mass

Estudio de la cinética de formación de nanopartículas de ZnO en dispersión coloidal

En el presente trabajo se estudian las primeras etapas relacionadas a la formación de nanopartículas de ZnO obtenidas por la aproximación coloidal. Se presentan resultados preliminares de la cinética de hidrólisis forzada del sistema ZnCl2 en presencia de NaOH a concentraciones controladas de agua en metanol. Es posible observar el fenómeno de nucleación y crecimiento por el control de la concentración de agua

Estudio de la cinética de formación de nanopartículas de ZnO en dispersión coloidal

En el presente trabajo se estudian las primeras etapas relacionadas a la formación de nanopartículas de ZnO obtenidas por la aproximación coloidal. El estudio aborda la evolución de los espectros de absorción electrónica en función del tiempo durante la nucleación del material en solución. Los resultados experimentales serán comparados con resultados teóricos obtenidos de la aplicación de metodologías de Dinámica Molecular Cuántica (DMC) que incluyen el efecto de la temperatura y del solvente en un sistema periódico. Para el estimar los posibles precursores que participan en los procesos de nucleación se aplican diferentes metodologías de cálculo teórico cuántico a nivel ab-initio

Regeneration of the dog's axotomized sciatic nerve with pregnenolone-saturated chitosan prosthesis implanted through the tubulization technique [Regeneración del nervio ciático axotomizado del perro con prótesis de quitosana precargadas con pregnenolona y la técnica de tubulización]

Peripheral nerves can be injured by traumatisms or mechanical causes, and thermal, ischemic or tumoral damage, this could present inconveniences of the mobility, sensibility and loss of motor function at the denervated area. The surgical techniques applied to repair nerves have gone through several phases of evolution such as the tubulization technique which consists of a prosthesis with a pipe shape at the segment injured. In this work the biomaterial utilized to manufacture the prosthesis was chitosan, since this compound allows to incorporate to its matrix promoting nervous growing substances that are released in situ for a long time while being degraded by titular lysosomes of organic origin. It is known, by diverse studies, that several neurosteroids are involved during the regeneration process of peripheral nerves, which functions are already described, as pregnenolone. In order to determine if there was or not regeneration and the degree of maturity of this,12 young French Poodle female dogs of 1 to 1.5 years old were used (four were used as intact control group, four were subjected to tubulization technique with chitosan, and four went into tubulization technique with chitosan and pregnenolone neurosteroid, which is a stem hormone), in order to correct 15 mm of axotomized segment. The regenerated nerves were evaluated by means of electronic microscopy of transmission and light, performing cross cuts of 60-70 nm and 1 μm in thickness for their histological analysis. The morphological findings showed a similar structure to that of an intact nerve, since the number of myelinated axons, not myelinated and the proportion "g" (which indicates the ripening degree of the axon), were similar, indicating that the regeneration of the axotomized nerves and tubulization was achieved, independently of the administered treatment

Valorization of Agrifood By-Products by Extracting Valuable Bioactive Compounds Using Green Processes

In Chapter 4, Valorization of Agrifood By-Products by Extracting Valuable BioactiveCompounds Using Green Processes, prepared by Carciochi et al., is presented the current challenge for the food industry, related to the exploitation of various by-products as sources of new commodities using eco-friendly technologies with an optimal cost-benefit relationship.The main green technologies used to recover natural products from agrifood by-products, such as enzyme-assisted extraction, ultrasound-assisted extraction, microwave-assisted extraction, electrically assisted extraction, pressurized liquid extraction, supercritical fluid extraction, and instant controlled pressure drop, are presented here.Fil: Carciochi, Ramiro Ariel. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; ArgentinaFil: D’Alessandro, Leandro G.. Artois University; FranciaFil: Vauchel, Peggy. Charles Viollette Institute; FranciaFil: Rodriguez, Maria Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría; ArgentinaFil: Nolasco, Susana Maria. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ingeniería Olavarría; ArgentinaFil: Dimitrov, Krasimir. Lille University; Franci

Regeneration of the dog's axotomized sciatic nerve with pregnenolone-saturated chitosan prosthesis implanted through the tubulization technique [Regeneraci�n del nervio ci�tico axotomizado del perro con pr�tesis de quitosana precargadas con pregnenolona y la t�cnica de tubulizaci�n]

Peripheral nerves can be injured by traumatisms or mechanical causes, and thermal, ischemic or tumoral damage, this could present inconveniences of the mobility, sensibility and loss of motor function at the denervated area. The surgical techniques applied to repair nerves have gone through several phases of evolution such as the tubulization technique which consists of a prosthesis with a pipe shape at the segment injured. In this work the biomaterial utilized to manufacture the prosthesis was chitosan, since this compound allows to incorporate to its matrix promoting nervous growing substances that are released in situ for a long time while being degraded by titular lysosomes of organic origin. It is known, by diverse studies, that several neurosteroids are involved during the regeneration process of peripheral nerves, which functions are already described, as pregnenolone. In order to determine if there was or not regeneration and the degree of maturity of this,12 young French Poodle female dogs of 1 to 1.5 years old were used (four were used as intact control group, four were subjected to tubulization technique with chitosan, and four went into tubulization technique with chitosan and pregnenolone neurosteroid, which is a stem hormone), in order to correct 15 mm of axotomized segment. The regenerated nerves were evaluated by means of electronic microscopy of transmission and light, performing cross cuts of 60-70 nm and 1 ?m in thickness for their histological analysis. The morphological findings showed a similar structure to that of an intact nerve, since the number of myelinated axons, not myelinated and the proportion "g" (which indicates the ripening degree of the axon), were similar, indicating that the regeneration of the axotomized nerves and tubulization was achieved, independently of the administered treatment