Evaluation of the Technical Viability of Distributed Mechanical Recycling of PLA 3D Printing Wastes.

3D printing PLA wastes were recovered from a well-known reference grade and from different sources. The recovered wastes were subjected to an energic washing step and then reprocessed into films by melt-extrusion, followed by compression molding to simulate the industrial processing conditions. The obtained materials were characterized and the optical, structural, thermal and crystallization behavior are reported. The mechanical recycling process leads to an increase of the crystallinity and a decrease of the intrinsic viscosity of the formulations, particularly in the sample based on blends of different 3D-PLA wastes. Moreover, the obtained films were disintegrated under composting conditions in less than one month and it was observed that recycled materials degrade somewhat faster than the starting 3D-PLA filament, as a consequence of the presence of shorter polymer chains. Finally, to increase the molecular weight of the recycled materials, the 3D-PLA wastes were submitted to a solid-state polymerization process at 110, 120, and 130 °C, observing that the recycled 3D-wastes materials based on a well-known reference grade experiences an improvement of the intrinsic viscosity, while that coming from different sources showed no significant changes. Thus, the results show that 3D printing PLA products provides an ideal environment for the implementation of distributed recycling program, in which wastes coming from well-known PLA grades can successfully be processed in films with good overall performance.

Cubic Anisotropic Co- and Zn-Substituted Ferrite Nanoparticles as Multimodal Magnetic Agents.

The use of magnetic nanoparticles as theranostic agents for the detection and treatment of cancer diseases has been extensively analyzed in the last few years. In this work, cubic-shaped cobalt and zinc-doped iron oxide nanoparticles with edge lengths in the range from 28 to 94 nm are proposed as negative contrast agents for magnetic resonance imaging and to generate localized heat by magnetic hyperthermia, obtaining high values of transverse relaxation coefficients and specific adsorption rates. The applied magnetic fields presented suitable characteristics for the potential validation of the results into the clinical practice in all cases. Pure iron oxide and cobalt- and zinc-substituted ferrites have been structurally and magnetically characterized, observing magnetite as the predominant phase and weak ferrimagnetic behavior at room temperature, with saturation values even larger than those of bulk magnetite. The coercive force increased due to the incorporation of cobalt ions, while zinc substitution promotes a significant increase in saturation magnetization. After their transfer to aqueous solution, those particles showing the best properties were chosen for evaluation in in vitro cell models, exhibiting high critical cytotoxic concentrations and high internalization degrees in several cell lines. The magnetic behavior of the nanocubes after their successful cell internalization was analyzed, detecting negligible variations on their magnetic hysteresis loops and a significant decrease in the specific adsorption rate values.

Treatment with the Ketone Body D-ß-hydroxybutyrate Attenuates Autophagy Activated by NMDA and Reduces Excitotoxic Neuronal Damage in the Rat Striatum In Vivo.

BACKGROUND: The ketone bodies (KB), ß-hydroxybutyrate (BHB) and acetoacetate, have been proposed for the treatment of acute and chronic neurological disorders, however, the molecular mechanisms involved in KB protection are not well understood. KB can substitute for glucose and support mitochondrial metabolism increasing cell survival. We have reported that the D-isomer of BHB (D-BHB) stimulates autophagic degradation during glucose deprivation in cultured neurons increasing cell viability. Autophagy is a lysosomal degradation process of damaged proteins and organelles activated during nutrient deprivation to obtain building blocks and energy. However, impaired or excessive autophagy can contribute to neuronal death. OBJECTIVE: The aim of the present study was to test whether D-BHB can preserve autophagic function in an in vivo model of excitotoxic damage induced by the administration of the glutamate receptor agonist, N-methyl-Daspartate (NMDA), in the rat striatum. METHODS: D-BHB was administered through an intravenous injection followed by either an intraperitoneal injection (i.v+i.p) or a continuous epidural infusion (i.v+pump), or through a continuous infusion of D-BHB alone. Changes in the autophagy proteins ATG7, ATG5, BECLIN 1 (BECN1), LC3, Sequestrosome1/p62 (SQSTM1/ p62) and the lysosomal membrane protein LAMP2, were evaluated by immunoblot. The lesion volume was measured in cresyl violet-stained brain sections. RESULTS: Autophagy is activated early after NMDA injection but autophagic degradation is impaired due to the cleavage of LAMP2. Twenty-four h after NMDA intrastriatal injection, the autophagic flux is re-established, but LAMP2 cleavage is still observed. The administration of D-BHB through the i.v+pump protocol reduced the content of autophagic proteins and the cleavage of LAMP2, suggesting decreased autophagosome formation and lysosomal membrane preservation, improving autophagic degradation. D-BHB also reduced brain injury. The i.v+i.p administration protocol and the infusion of D-BHB alone showed no effect on autophagy activation or degradation.

Multicatalysis Combining 3D-Printed Devices and Magnetic Nanoparticles in One-Pot Reactions: Steps Forward in Compartmentation and Recyclability of Catalysts.

A tricatalytic compartmentalized system that immobilizes metallic species to perform one-pot sequential functionalization is described: a three-dimensional (3D)-printed palladium monolith, ferritic copper(I) magnetic nanoparticles, and a 3D-printed polypropylene capsule-containing copper(II) loaded onto polystyrene-supported 1,5,7-triazabicyclo[4.4.0]dec-5-ene (PS-TBD) allowed the rapid synthesis of diverse substituted 1-([1,1'-biphenyl]-4-yl)-1H-1,2,3-triazoles. The procedure is based on the Chan-Lam azidation/copper alkyne-azide cycloaddition/Suzuki reaction strategy in the solution phase. This catalytic system enabled the efficient assembly of the final compounds in high yields without the need for special additives or intermediate isolation. The monolithic catalyst-containing immobilized palladium species was synthesized by surface chemical modification of a 3D-printed silica monolith using a soluble polyimide resin as a key reagent, thus creating an extremely robust composite. All three immobilized catalysts described here were easily recovered and reused in numerous cycles. This work exemplifies the role of 3D printing in the design and manufacture of devices for compartmented multicatalytic systems to carry out complex one-pot transformations.

Leaf wax n-alkane patterns of six tropical montane tree species show species-specific environmental response.

It remains poorly understood how the composition of leaf wax n-alkanes reflects the local environment. This knowledge gap inhibits the interpretation of plant responses to the environment at the community level and, by extension, inhibits the applicability of n-alkane patterns as a proxy for past environments. Here, we studied the n-alkane patterns of five Miconia species and one Guarea species, in the Ecuadorian Andes (653-3,507 m a.s.l.). We tested for species-specific responses in the average chain length (ACL), the C31/(C31 + C29) ratio (ratio), and individual odd n-alkane chain lengths across an altitudinally driven environmental gradient (mean annual temperature, mean annual relative air humidity, and mean annual precipitation). We found significant correlations between the environmental gradients and species-specific ACL and ratio, but with varying magnitude and direction. We found that the n-alkane patterns are species-specific at the individual chain length level, which could explain the high variance in metrics like ACL and ratio. Although we find species-specific sensitivity and responses in leaf n-alkanes, we also find a general decrease in "shorter" (C31) chain lengths with the environmental gradients, most strongly with temperature, suggesting n-alkanes are useful for reconstructing past environments.

Availability, diversification and versatility explain human selection of introduced plants in Ecuadorian traditional medicine.

Globally, a majority of people use plants as a primary source of healthcare and introduced plants are increasingly discussed as medicine. Protecting this resource for human health depends upon understanding which plants are used and how use patterns will change over time. The increasing use of introduced plants in local pharmacopoeia has been explained by their greater abundance or accessibility (availability hypothesis), their ability to cure medical conditions that are not treated by native plants (diversification hypothesis), or as a result of the introduced plants' having many different simultaneous roles (versatility hypothesis). In order to describe the role of introduced plants in Ecuador, and to test these three hypotheses, we asked if introduced plants are over-represented in the Ecuadorian pharmacopoeia, and if their use as medicine is best explained by the introduced plants' greater availability, different therapeutic applications, or greater number of use categories. Drawing on 44,585 plant-use entries, and the checklist of >17,000 species found in Ecuador, we used multi-model inference to test if more introduced plants are used as medicines in Ecuador than expected by chance, and examine the support for each of the three hypotheses above. We find nuanced support for all hypotheses. More introduced plants are utilized than would be expected by chance, which can be explained by geographic distribution, their strong association with cultivation, diversification (except with regard to introduced diseases), and therapeutic versatility, but not versatility of use categories. Introduced plants make a disproportionately high contribution to plant medicine in Ecuador. The strong association of cultivation with introduced medicinal plant use highlights the importance of the maintenance of human-mediated environments such as homegardens and agroforests for the provisioning of healthcare services.

An integrated assessment of the vascular plant species of the Americas.

The cataloging of the vascular plants of the Americas has a centuries-long history, but it is only in recent decades that an overview of the entire flora has become possible. We present an integrated assessment of all known native species of vascular plants in the Americas. Twelve regional and national checklists, prepared over the past 25 years and including two large ongoing flora projects, were merged into a single list. Our publicly searchable checklist includes 124,993 species, 6227 genera, and 355 families, which correspond to 33% of the 383,671 vascular plant species known worldwide. In the past 25 years, the rate at which new species descriptions are added has averaged 744 annually for the Americas, and we can expect the total to reach about 150,000.

Síndrome de shock tóxico no menstrual: presentación de un caso y revisión de la literatura / Non-menstrual toxic shock: report of a case and review of the literature

El Síndrome de Shock Tóxico (SST) asociado con Estafilococo Aureus se presenta más frecuentemente en mujeres, sobre todo en período menstrual y en aquellas que utilizan tampones vaginales. Es una entidad febril aguda con un amplio espectro clínico caracterizado básicamente por hipertermia, eritrodermia, descamación, hipotensión, disfunsión de varios órganos, gran tendencia a la recurrencia, que presenta un diagnóstico diferencial amplio y difícil y que puede dejar secuelas a largo plazo

Síndrome de shock tóxico no menstrual: presentación de un caso y revisión de la literatura / Non-menstrual toxic shock: report of a case and review of the literature

El Síndrome de Shock Tóxico (SST) asociado con Estafilococo Aureus se presenta más frecuentemente en mujeres, sobre todo en período menstrual y en aquellas que utilizan tampones vaginales. Es una entidad febril aguda con un amplio espectro clínico caracterizado básicamente por hipertermia, eritrodermia, descamación, hipotensión, disfunsión de varios órganos, gran tendencia a la recurrencia, que presenta un diagnóstico diferencial amplio y difícil y que puede dejar secuelas a largo plazo (AU)