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In a recent work (Castanon Quiroz & Di Pietro (2020) A hybrid high-order method for the incompressible Navier–Stokes problem robust for large irrotational body forces. Comput. Math. Appl. , 79 , 2655–2677), we have introduced a pressure-robust hybrid high-order method for the numerical solution of the incompressible Navier–Stokes equations on matching simplicial meshes. Pressure-robust methods are characterized by error estimates for the velocity that are fully independent of the pressure. A crucial question was left open in that work, namely whether the proposed construction could be extended to general polytopal meshes. In this paper, we provide a positive answer to this question. Specifically, we introduce a novel divergence-preserving velocity reconstruction that hinges on the solution inside each element of a mixed problem on a subtriangulation, then use it to design discretizations of the body force and convective terms that lead to pressure robustness. An in-depth theoretical study of the properties of this velocity reconstruction, and their reverberation on the scheme, is carried out for arbitrary polynomial degrees |$k\geq 0$| and meshes composed of general polytopes. The theoretical convergence estimates and the pressure robustness of the method are confirmed by an extensive panel of numerical examples. [ABSTRACT FROM AUTHOR]

In this work, we design and analyse a Hybrid High-Order (HHO) discretization method for incompressible flows of non-Newtonian fluids with power-like convective behaviour. We work under general assumptions on the viscosity and convection laws, which are associated with possibly different Sobolev exponents |$r\in (1,\infty)$| and |$s\in (1,\infty)$|⁠. After providing a novel weak formulation of the continuous problem, we study its well-posedness highlighting how a subtle interplay between the exponents |$r$| and |$s$| determines the existence and uniqueness of a solution. We next design an HHO scheme based on this weak formulation, and perform a comprehensive stability and convergence analysis, including convergence for general data and error estimates for shear-thinning fluids and small data. The HHO scheme is validated on a complete panel of model problems. [ABSTRACT FROM AUTHOR]

The immersion-analogue of Hadwiger's Conjecture states that every graph G contains an immersion of K χ (G). This conjecture has been recently strengthened in the following way: every graph G contains a totally odd immersion of K χ (G). We prove this stronger conjecture for line graphs of constant-multiplicity multigraphs, thus extending a result of Guyer and McDonald. [ABSTRACT FROM AUTHOR]

In this paper, we design and analyze a Hybrid High-Order discretization method for the steady motion of non-Newtonian, incompressible fluids in the Stokes approximation of small velocities. The proposed method has several appealing features including the support of general meshes and high-order, unconditional inf-sup stability, and orders of convergence that match those obtained for scalar Leray–Lions problems. A complete well-posedness and convergence analysis of the method is carried out under new, general assumptions on the strain rate-shear stress law, which encompass several common examples such as the power-law and Carreau–Yasuda models. Numerical examples complete the exposition. [ABSTRACT FROM AUTHOR]

N-alkyl-substituted polyacrylamides exhibit a thermal coil-to-globule transition in aqueous solution driven by an increase in hydrophobic interactions with rising temperature. With the aim of understanding the role of N-alkyl substituents in the thermal transition, this study focuses on the molecular interactions underlying the phase transition of poly(N,N-diethylacrylamide-co-N-ethylacrylamide) random copolymers. Poly(N,N-diethylacrylamide) (PDEAm), poly(N-ethylacrylamide) (PNEAm), and their random copolymers were synthesized by free radical polymerization and their chemical structure characterized spectroscopically. It was found that the values of the cloud-point temperature increased with PNEAm content, and particle aggregation processes took place, increasing the negative charge density on their surface. The cloud-point temperature of each copolymer decreased with respect to the theoretical values calculated assuming an absence of interactions. It is attributed to the formation of intra- and interchain hydrogen bonding in aqueous solutions. These interactions favor the formation of more hydrophobic macromolecular segments, thereby promoting the cooperative nature of the transition. These results definitively reveal the dominant mechanism occurring during the phase transition in the aqueous solutions of these copolymers. [ABSTRACT FROM AUTHOR]

We develop a novel Hybrid High-Order method for the incompressible Navier–Stokes problem robust for large irrotational body forces. The key ingredients of the method are discrete versions of the body force and convective contributions in the momentum equation formulated in terms of a globally divergence-free velocity reconstruction. Two key properties are mimicked at the discrete level, namely the invariance of the velocity with respect to irrotational body forces and the non-dissipativity of the convective term. A full convergence analysis is carried out, showing optimal orders of convergence under a smallness condition involving only the solenoidal part of the body force. The performance of the method is illustrated by a complete panel of numerical tests, including comparisons that highlight the benefits with respect to more standard formulations. [ABSTRACT FROM AUTHOR]

Given two n-vertex graphs G1 and G2 of bounded treewidth, is there an n-vertex graph G of bounded treewidth having subgraphs isomorphic to G1 and G2? Our main result is a negative answer to this question, in a strong sense: we show that the answer is no even if G1 is a binary tree and G2 is a ternary tree. We also provide an extensive study of cases where such "gluing"" is possible. In particular, we prove that if G1 has treewidth k and G2 has pathwidth \l, then there is an n-vertex graph of treewidth at most k + 3\l + 1 containing both G1 and G2 as subgraphs. [ABSTRACT FROM AUTHOR]

The history of the commercial hunting of whales in Chile allows us to distinguish three foreign whaling traditions, which we shall call the "Yankee", the "Norwegian" and the "Japanese", which inserted themselves into a pre-existing tradition: passive hunting or the butchering of whales stranded on beaches undertaken not only by the native populations but Europeans and their descendants as well. This montage of traditions shapes a sequence of superposed processes which have been narrated by a group of contemporary observers of these events. A review of the accounts written by these observers reveals different conceptual constructions about whales (as a "monster", "resource" and "scarce resource") and the whale hunters (as "heroes" and "professionals"), linked to the technological evolution of whale hunting in our country (passive hunting, traditional hunting, modern hunting). [ABSTRACT FROM AUTHOR]

The analogue of Hadwiger's conjecture for the immersion order states that every graph G contains K χ (G) as an immersion. If true, this would imply that every graph with n vertices and independence number α contains K ⌈ n α ⌉ as an immersion. The best currently known bound for this conjecture is due to Gauthier, Le and Wollan, who recently proved that every graph G contains an immersion of a clique on ⌈ χ (G) − 4 3. 54 ⌉ vertices. Their result implies that every n -vertex graph with independence number α contains an immersion of a clique on ⌈ n 3. 54 α − 1. 13 ⌉ vertices. We improve on this result for all α ≥ 3 , by showing that every n -vertex graph with independence number α ≥ 3 contains an immersion of a clique on ⌊ n 2. 25 α − f (α) ⌋ − 1 vertices, where f is a nonnegative function. [ABSTRACT FROM AUTHOR]

Conformational changes of the thermal transitions of chitosan- graft-poly( N-vinylcaprolactam) copolymers in aqueous solution were studied by varying of the length of the grafted poly( N-vinylcaprolactam) (PVCL) chains, as well as the ionic strength and the pH of the solution. The conformational properties of the copolymer were monitored by means of dynamic light scattering and ζ-potential measurements. A series of copolymers with defined molecular architecture were synthesized. Obtained results point out that hydrophobic hydration plays a crucial role on the solubility of this copolymer at neutral and slightly alkaline solutions. The evolution of the size of macromolecular aggregates indicates that, in the coil state, there is a monomodal distribution, passing through a bimodal distribution in the pre-transition region, just before the phase separation. The role of the charge of the copolymers on the cooperative transition is also analyzed. The phase transition of these amphiphilic copolymers shows a strong dependence on the ionic strength of the solution. [ABSTRACT FROM AUTHOR]

A series of thermoresponsive copolymers based on chitosan- g -poly( N -vinylcaprolactam) were synthesized by amidation reaction using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride as coupling reagent. The effect of molecular architecture on the thermoresponsive properties of the graft copolymers solutions was studied by varying the chain length of the grafted poly( N -vinylcaprolactam), PVCL, (in the range from 4 to 26 kDa) and the spacing between grafted chains onto the chitosan backbone. The most interesting characteristic of these copolymers is their solubility in water at temperatures below their lower critical solution temperature (LCST). These solutions presented a LCST between 36 and 44 °C, which decreases with the spacing and length of grafted PVCL chains onto the chitosan backbone, in contrast with the limited decrease of the LCST of PVCL above a critical M ¯ n value around 18 kDa. This behavior offers tangible possibilities for the preparation and application of sensitive bioactive formulations and “smart” drug delivery systems. [ABSTRACT FROM AUTHOR]

A chronological database of 398 dates (247 14 C dates, 148 thermoluminescence dates, and 3 obsidian hydration dates), covering the early peopling period up to the present, is presented for Southern Chile. This information is used to assess both the paleodemography, understood as human population dynamics in the past; and the “archaeo-demography”, understood as the research dynamics of archaeologists in the present, of that region. From the early peopling up to the Late Archaic, information is geographically and chronologically scarce and scattered, the exception being the coast. For this latter area, it is possible to posit the existence of an occupation hiatus extending from at least around 3400 cal BP to around 2350 cal BP. After this latter date, a regional incremental trend is evident, along with the earliest presence of ceramics, as well as evidence of probable horticultural practices. On the other hand, the coast, compared to the valley and cordillera, has been the most active area for archaeological research and dating since the 1990s. This database as a whole helps to expose research biases and current gaps, in order to improve and expand our knowledge of the long history of Southern Chile's human occupation. [ABSTRACT FROM AUTHOR]

A word on q symbols is a sequence of letters from a fixed alphabet of size q. For an integer k ⩾ 1 , we say that a word w is k -universal if, given an arbitrary word of length k , one can obtain it by removing letters from w. It is easily seen that the minimum length of a k -universal word on q symbols is exactly qk. We prove that almost every word of size (1 + o (1)) c q k is k -universal with high probability, where c q is an explicit constant whose value is roughly q log ⁡ q. Moreover, we show that the k -universality property for uniformly chosen words exhibits a sharp threshold. Finally, by extending techniques of Alon (2017) [1] , we give asymptotically tight bounds for every higher dimensional analogue of this problem. [ABSTRACT FROM AUTHOR]

In 2007, based on direct radiocarbon dates, we presented evidence that chickens were introduced to Chile before Europeans first made contact with the New World. The pre- Columbian age of the chicken bones and their mtDNA affinities with one of two prehistoric Pacific chicken haplogroups ( E) led us to conclude that Polynesia was the most likely origin for these pre- Columbian chickens. Subsequently, the mtDNA and radiocarbon evidence provided has been applied to a range of studies and occasionally reinterpreted. This has revealed issues related to the brevity of the initial report in 2007. Here, we provide a full discussion of the evidence, including the relevant archaeological, historical and biological information necessary to provide the context for interpreting genetic analyses and understanding their implications for addressing archaeological questions. We include a comprehensive analysis of the isotope data within a geographical and temporally relevant dataset to verify the pre- Columbian age of the El Arenal chickens. In addition, we provide longer DNA sequences obtained from some of the ancient Chilean chicken remains to address objections raised by critics and to demonstrate that longer sequences do not change the observed affinities of the mtDNA sequences, nor their interpretation. In this analysis, historical information is used to critically evaluate the results of phylogenetic analyses. This comprehensive approach demonstrates that the examination of modern chicken DNA sequences does not contribute to our understanding of the origins of Chile's earliest chickens. Interpretations based on poorly sourced and documented modern chicken populations, divorced from the archaeological and historical evidence, do not withstand scrutiny. Instead, this expanded account will confirm the pre- Columbian age of the El Arenal remains and lend support to our original hypothesis that their appearance in South America is most likely due to Polynesian contact with the Americas in prehistory. [ABSTRACT FROM AUTHOR]

Introduction. Prolonged exposure to high temperatures can pose a major assault to the body when it can not adapt to high temperatures and is unable to rehydrate. Neurologic manifestations accompanying increase in body temperature is most likely to avoid an early diagnosis of heat stroke and cause death if not taken the initial steps necessary. Little is known about the morbidity and mortality from exposure to extreme temperatures and their consequences, the data are not precise because it is underdiagnosed or variability in the definition of this condition. When the core temperature increases, the center active thermoregulatory efferent fibers of the autonomic nervous system that increases heat loss by producing cutaneous vasodilation (convection) and increased sweating (evaporation). The ability to maintain a high body temperature vasoconstriction (42 °C) may be lost, marking the onset of circulatory collapse. The mechanism underlying the marked vasodilation in the mesenteric artery is unknown, the loss of compensatory vasoconstriction does not appear to be due to the reduction of efferent nerve conduction to the region, since the splenic sympathetic nerve activity and plasma catecholamine levels are elevated for moderate and severe hyperthermia. The α1-adrenergic vascular postsynaptic play a role in the maintenance of peripheral vascular resistance and therefore in control of systemic arterial pressure, there are three subtypes of α1-adrenergic receptor functional α1A, α1B, α1D, which mediates vaso constriction nice and so modulate vascular resistance. In the previous studies did not mention the specific action or expression levels of α1 adrenergic receptors during hyperthermia, which can lead to a specific response that is what drives the body into a state of shock, where failure CVD is a key point for treatment, so it is important to try to explain what the possible answer to this disease in the future can be better studied. Objective. The aim of this study was to determine the response and the expression of α1-adrenergic receptors of mouse mesenteric vascular bed exposed to hyperthermia. Material and methods. Two groups of mice to the development of physiological and molecular, which in the case of physiological studies was divided into a control group at 37 ºC and four experimental groups were exposed to 38, 39 40 and 41 ºC using a model of isolated organ for the implementation of Curves Concentration response in the case of molecular studies was divided into a control group at 37 °C and two experimental groups at 39 and 41 ºC to which they perform PCR real time to analyze the expression of α1 adrenergic receptors to be exposed to different temperatures using the method of 2-ΔΔCT (Livak y cols. 2001). Statistical analysis of data and graphs were performed using Sigma STAT software Sigma Plot version 2.03 and 10.0. ANOVA and Tukey was used to compare changes in expression of α1 adrenergic receptors in mouse mesenteric vascular bed exposed to 37. 39 and 41 ºC. Results: Both groups reduced the response of α1 adrenergic receptors in dose-response curves for concentration decreased appreciate the response to stimulation with non-selective and selective agonist for α1 adrenergic as well as reduction of the maximum response generated by the drug under Increasing the temperature, when performing real-time PCR we observed an increase in receptor expression α1A and α1B adrenergic 39 and 41 ºC, which occurs in α1D adrenergic more important because its expression increases 500 times compared to the control at 37 °C decreasing to zero when exposed to 41 ºC. [ABSTRACT FROM AUTHOR]

The Lescure–Meyniel conjecture is the analogue of Hadwiger's conjecture for the immersion order. It states that every graph G contains the complete graph K χ (G) as an immersion, and like its minor-order counterpart it is open even for graphs with independence number 2. We show that every graph G with independence number α (G) ≥ 2 and no hole of length between 4 and 2 α (G) satisfies this conjecture. In particular, every C 4 -free graph G with α (G) = 2 satisfies the Lescure–Meyniel conjecture. We give another generalisation of this corollary, as follows. Let G and H be graphs with independence number at most 2, such that | V (H) | ≤ 4. If G is H -free, then G satisfies the Lescure–Meyniel conjecture. [ABSTRACT FROM AUTHOR]

For a graph G = (V , E) and positive integer p , the exact distance- p graph G [ ♮ p ] is the graph with vertex set V and with an edge between vertices x and y if and only if x and y have distance p. Recently, there has been an effort to obtain bounds on the chromatic number χ (G [ ♮ p ] ) of exact distance- p graphs for G from certain classes of graphs. In particular, if a graph G has tree-width t , it has been shown that χ (G [ ♮ p ] ) ∈ O (p t − 1) for odd p , and χ (G [ ♮ p ] ) ∈ O (p t Δ (G)) for even p. We show that if G is chordal and has tree-width t , then χ (G [ ♮ p ] ) ∈ O (p t 2) for odd p , and χ (G [ ♮ p ] ) ∈ O (p t 2 Δ (G)) for even p. If we could show that for every graph H of tree-width t there is a chordal graph G of tree-width t which contains H as an isometric subgraph (i.e., a distance preserving subgraph), then our results would extend to all graphs of tree-width t. While we cannot do this, we show that for every graph H of genus g there is a graph G which is a triangulation of genus g and contains H as an isometric subgraph. [ABSTRACT FROM AUTHOR]

Natural cyclodextrins (CDs) can be formed by 6, 7, or 8 glucose molecules (α-, β-, and γ-, respectively) linked in a ring, creating a cone shape. Its interior has an affinity for hydrophobic molecules, while the exterior is hydrophilic and can interact with water molecules. This feature has been used to develop active packaging applied to food, interacting with the product or its environment to improve one or more aspects of its quality or safety. It also provides monitoring information when food is optimal for consumption, as intelligent packaging is essential for the consumer and the merchant. Therefore, this review will focus on discerning which packaging is most appropriate for each situation, solubility and toxicological considerations, characterization techniques, effect on the guest properties, and other aspects related to forming the inclusion complex with bioactive molecules applied to packaging. [ABSTRACT FROM AUTHOR]

Abstract For any graph G = (V , E) and positive integer p , the exact distance-p graph G [ ♮ p ] is the graph with vertex set V , which has an edge between vertices x and y if and only if x and y have distance p in G. For odd p , Nešetřil and Ossona de Mendez proved that for any fixed graph class with bounded expansion , the chromatic number of G [ ♮ p ] is bounded by an absolute constant. Using the notion of generalised colouring numbers , we give a much simpler proof for the result of Nešetřil and Ossona de Mendez, which at the same time gives significantly better bounds. In particular, we show that for any graph G and odd positive integer p , the chromatic number of G [ ♮ p ] is bounded by the weak (2 p − 1) -colouring number of G. For even p , we prove that χ (G [ ♮ p ]) is at most the weak (2 p) -colouring number times the maximum degree. For odd p , the existing lower bound on the number of colours needed to colour G [ ♮ p ] when G is planar is improved. Similar lower bounds are given for K t -minor free graphs. [ABSTRACT FROM AUTHOR]

The functionalization of polymeric substances is of great interest for the development of innovative materials for advanced applications. For many decades, the functionalization of chitosan has been a convenient way to improve its properties with the aim of preparing new materials with specialized characteristics. In the present review, we summarize the latest methods for the modification and derivatization of chitin and chitosan under experimental conditions, which allow a control over the macromolecular architecture. This is because an understanding of the interdependence between chemical structure and properties is an important condition for proposing innovative materials. New advances in methods and strategies of functionalization such as the click chemistry approach, grafting onto copolymerization, coupling with cyclodextrins, and reactions in ionic liquids are discussed. [ABSTRACT FROM AUTHOR]

The generalised colouring numbers col r ( G ) and wcol r ( G ) were introduced by Kierstead and Yang as a generalisation of the usual colouring number, and have since then found important theoretical and algorithmic applications. In this paper, we dramatically improve upon the known upper bounds for generalised colouring numbers for graphs excluding a fixed minor, from the exponential bounds of Grohe et al. to a linear bound for the r -colouring number col r and a polynomial bound for the weak r -colouring number wcol r . In particular, we show that if G excludes K t as a minor, for some fixed t ≥ 4 , then col r ( G ) ≤ t − 1 2 ( 2 r + 1 ) and wcol r ( G ) ≤ r + t − 2 t − 2 ( t − 3 ) ( 2 r + 1 ) ∈ O ( r t − 1 ) . In the case of graphs G of bounded genus g , we improve the bounds to col r ( G ) ≤ ( 2 g + 3 ) ( 2 r + 1 ) (and even col r ( G ) ≤ 5 r + 1 if g = 0 , i.e. if G is planar) and wcol r ( G ) ≤ ( 2 g + r + 2 2 ) ( 2 r + 1 ) . [ABSTRACT FROM AUTHOR]

The development of stimuli-responsive release systems as functional platforms for controlled drug delivery is a valuable contribution to modern-day medical practice. In this work, novel electroactive nanocomposite hydrogels were prepared by encapsulating green-synthesized polypyrrole (PPy) colloids within bioamine-crosslinked gellan gum (GG) networks. The structural, physicochemical, and morphological properties of GG/PPy hydrogels were studied by Fourier transform infrared spectroscopy, thermogravimetry, rheological analysis, scanning electron microscopy, and swelling kinetic measurements. The hydrogels exhibited an interconnected porous structure with undefined boundaries. Viscoelastic properties and swelling behavior of materials were dependent on their filler content. In vitro ibuprofen (IBP) release studies from hydrogels were carried out without and under different electrical stimulations. The IBP release kinetic from GG/PPy hydrogels was remarkably activated by electrical stimuli. A unique pulse potential of 5 V increased the drug delivery up to 63% from nanocomposite hydrogel, in contrast to the low IBP amount released in a passive form (10%). The PPy reduction played a determining role as the main driving force in drug release activation. The tuning release profiles evidenced the potential of materials for electrically controlled drug delivery in implantable or transdermal drug release devices. [Display omitted] • Green-synthesized PPy colloids were embedded within bioamine-crosslinked GG networks. • The viscoelastic properties of 3D networks depend on PPy content. • Low IBP amounts were released from hydrogels in passive conditions. • Only with the electrical stimulation of hydrogels, the drug is released on command. • The PPy colloids played a determining role in the drug release activation. [ABSTRACT FROM AUTHOR]

For a graph G = (V , E) , its exact-distance square , G [ ♯ 2 ] , is the graph with vertex set V and with an edge between vertices x and y if and only if x and y have distance (exactly) 2 in G. The graph G is an exact-distance square root of G [ ♯ 2 ]. We give a characterization of graphs having an exact-distance square root, our characterization easily leading to a polynomial-time recognition algorithm. We show that it is NP-complete to recognize graphs with a bipartite exact-distance square root. These two results strongly contrast known results on (usual) graph squares. We then characterize graphs having a tree as an exact-distance square root, and from this obtain a polynomial-time recognition algorithm for these graphs. Finally, we show that, unlike for usual square roots, a graph might have (arbitrarily many) non-isomorphic exact-distance square roots which are trees. [ABSTRACT FROM AUTHOR]

Two issues long debated among Pacific and American prehistorians are (11 whether there was a pre-Columbian introduction of chicken (Gallus gallus) to the Americas and (ii) whether Polynesian contact with South America might be identified archaeologically, through the recovery of remains of unquestionable Polynesian origin. We present a radiocarbon date and an ancient DNA sequence from a single chicken bone recovered from the archaeological site of El Arenal-1, on the Arauco Peninsula, Chile. These results not only provide firm evidence for the pre-Columbian introduction of chickens to the Americas, but strongly suggest that it was a Polynesian introduction. [ABSTRACT FROM AUTHOR]

During the last thirty years, shelterwood cuts has been the most applied regeneration method in Nothofagus pumilio (lenga) forests. This treatment was implemented without any consideration of the landscape, and without considering yield gradients (e.g. stand site qualities), environmental restrictions (e.g. soil water availability) or potential natural disturbance factors (e.g. wind exposure). The objective was to evaluate the dynamics of the remnant forest structure and the natural regeneration 10 years after harvesting across the landscape considering different environmental gradients. Sampling plots were established in nine stands distributed across Tierra del Fuego, Argentina (north, east and south areas) where forestry activity has been concentrated during the last years. The selected areas presented differences in the rainfall regime (402 to 446 mm yr-1) and site qualities of the stands (2.6 to 3.3). Forest structure was similar among the studied areas, nevertheless harvesting intensity was variable (30 % to 57 %) generating different remnant basal areas (BA) (22 to 47 m2 ha-1) and woody debris accumulation in the forest floor (167 to 230 m3 ha-1) after harvesting, or in combination with local wind-throws. The current forest structure presented differences in BA (6 to 34 m2 ha-1) and established regeneration (49 to 110 thousand ha-1) that varied in height (0.6 to 1.0 m) and growth (4.1 to 12.8 cm yr-1) according to the area and the received damage due to abiotic and biotic factors. We can conclude that forests located along the considered landscapes and environmental gradients differentially responded to the proposed silvicultural treatments, where climate influenced over the post-harvest canopy stability and the established regeneration. For this, it is mandatory to define different silvicultural strategies throughout the landscape. [ABSTRACT FROM AUTHOR]

In recent decades, cobalt catalyst has represented a powerful strategy for developing common organic reactions. This review includes the most recent efforts of Co catalysts applications in selective organic reactions such as C–H & C—X activation, hydrogenation & dehydrogenation, and cycloaddition. The contribution of cobalt salt or earth-abundant cobalt complexes usually accomplishes these reactions. It mainly involves different fundamental reaction paths, such as the concerted metalation-deprotonation (CMD) path associated with non-oxidative C–H activation and the intermolecular single-electron transfer (SET) path. Here, we summarize the advances of Co catalyst applications in three main sections: (i) C–H & C—X activation, (ii) hydrogenation-dehydrogenation, and (iii) cycloaddition. The characteristics of each catalyst are discussed according to parameters such as efficiency, recyclability, catalyst life, lack of catalyst nanoparticles agglomeration, and required time of catalyst effects on the reactions. [Display omitted] [ABSTRACT FROM AUTHOR]

Retinal neovascularization is a critical component in the pathogenesis of common ocular disorders that cause blindness, and treatment options are limited. We evaluated the therapeutic effect of a DNA enzyme targeting c-jun mRNA in mice with preexisting retinal neovascularization. A single injection of Dz13 in a lipid formulation containing N-[1-(2,3-dioleoyloxy)propyl]- N,N,N-trimethylammonium methyl-sulfate and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine inhibited c-Jun expression and reduced retinal microvascular density. The DNAzyme inhibited retinal microvascular density as effectively as VEGF-A antibodies. Comparative microarray and gene expression analysis determined that Dz13 suppressed not only c-jun but a range of growth factors and matrix-degrading enzymes. Dz13 in this formulation inhibited microvascular endothelial cell proliferation, migration and tubule formation in vitro. Moreover, animals treated with Dz13 sensed the top of the cage in a modified forepaw reach model, unlike mice given a DNAzyme with scrambled RNA-binding arms that did not affect c-Jun expression. These findings demonstrate reduction of microvascular density and improvement in forepaw reach in mice administered catalytic DNA. [ABSTRACT FROM AUTHOR]

One of the main challenges facing materials science today is the synthesis of new biodegradable and biocompatible materials capable of improving existing ones. This work focused on the synthesis of new biomaterials from the bioconjugation of oleic acid with L-cysteine using carbodiimide. The resulting reaction leads to amide bonds between the carboxylic acid of oleic acid and the primary amine of L-cysteine. The formation of the bioconjugate was corroborated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and nuclear magnetic resonance (NMR). In these techniques, the development of new materials with marked differences with the precursors was confirmed. Furthermore, NMR has elucidated a surfactant structure, with a hydrophilic part and a hydrophobic section. Ultraviolet-visible spectroscopy (UV-Vis) was used to determine the critical micellar concentration (CMC) of the bioconjugate. Subsequently, light diffraction (DLS) was used to analyze the size of the resulting self-assembled structures. Finally, transmission electron microscopy (TEM) was obtained, where the shape and size of the self-assembled structures were appreciated. [ABSTRACT FROM AUTHOR]