83 research outputs found
Dinámica temporal de la disponibilidad de agua y microclima en aguadas del biotopo protegido Dos Lagunas, Petén, Guatemala
En el territorio de la Selva Maya se han identificado a los cuerpos de agua estacionales denominados localmente aguadas, como un recurso crítico para la supervivencia de especies de fauna silvestre, ya que son su principal fuente de agua durante la temporada seca. En el presente estudio se registró en cinco aguadas, la dinámica temporal de la acumulación de agua empleando una cámara automática, así como la temperatura y la humedad relativa utilizando sensores automáticos a lo largo de abril a agosto del 2016. En cuanto a la disponibilidad de agua, esta fue disminuyendo hasta agotarse al final de la temporada seca en el mes de abril, y fue aumentando al inicio de la temporada lluviosa en junio. Para la temporada seca se registró una temperatura promedio (desviación estándar) de 27.65 (4.52)ªC y una humedad relativa de 71.30 (19.00)%, mientras que para la temporada lluviosa la temperatura promedio fue de 26.09 (3.21)ªC y humedad relativa promedio de 86.16 (14.15)%. Sin embargo no se encontró una diferencia significativa entre los valores registrados en las "distintas" aguadas. Se encontró una correlación significativa entre los valores registrados en las aguadas con los registrados por la estación meteorológica automática (EMA) Calakmul II, por lo que para estudios futuros es posible utilizar los valores de la EMA para representar la dinámica en las aguadas. Entre las estrategias para reducir los potenciales efectos del cambio climático para la fauna es la conservación de las aguadas manteniendo la conectividad entre las mismas
A nature-inspired design yields a new class of steroids against trypanosomatids
This article belongs to the Special Issue Drug Discovery for Neglected DiseasesChagas disease and Leishmaniasis are neglected endemic protozoan diseases recognized as public health problems by the World Health Organization. These diseases affect millions of people around the world however, efficient and low-cost treatments are not available. Different steroid molecules with antimicrobial and antiparasitic activity were isolated from diverse organisms (ticks, plants, fungi). These molecules have complex structures that make de novo synthesis extremely difficult. In this work, we designed new and simpler compounds with antiparasitic potential inspired in natural steroids and synthesized a series of nineteen steroidal arylideneketones and thiazolidenehydrazines. We explored their biological activity against Leishmania infantum, Leishmania amazonensis, and Trypanosoma cruzi in vitro and in vivo. We also assayed their genotoxicity and acute toxicity in vitro and in mice. The best compound, a steroidal thiosemicarbazone compound 8 (ID_1260) was active in vitro (IC50 200 nM) and in vivo (60% infection reduction at 50 mg/kg) in Leishmania and T. cruzi. It also has low toxicity in vitro and in vivo (LD50 >2000 mg/kg) and no genotoxic effects, being a promising compound for anti-trypanosomatid drug development
The clinical and molecular cardiometabolic fingerprint of an exploratory psoriatic arthritis cohort is associated with the disease activity and differentially modulated by methotrexate and apremilast
Objectives: (1) To evaluate clinical and molecular cardiovascular disease (CVD) signs and their relationship with psoriatic arthritis (PsA) features and (2) to identify a clinical patient profile susceptible to benefit from methotrexate (MTX) and/or apremilast regarding CVD risk. Methods: This cross-sectional study included 100 patients with PsA and 100 age-matched healthy donors. In addition, an exploratory cohort of 45 biologically naïve patients treated for 6 months with apremilast, MTX or combined therapy according to routine clinical practice was recruited. Extensive clinical and metabolic profiles were obtained. Ninety-nine surrogate CVD-related molecules were analysed in plasma and peripheral blood mononuclear cells (PBMCs). Hard cluster analysis was performed to identify the clinical and molecular phenotypes. Mechanistic studies were performed on adipocytes. Results: Cardiometabolic comorbidities were associated with disease activity and long-term inflammatory status. Thirty-five CVD-related proteins were altered in the plasma and PBMCs of PsA patients and were associated with the key clinical features of the disease. Plasma levels of some of the CVD-related molecules might distinguish insulin-resistant patients (MMP-3, CD163, FABP-4), high disease activity (GAL-3 and FABP-4) and poor therapy outcomes (CD-163, LTBR and CNTN-1). Hard cluster analysis identified two phenotypes of patients according to the rates of cardiometabolic comorbidities with distinctive clinical and molecular responses to each treatment. Conclusions: (1) Novel CVD-related proteins associated with clinical features could be emerging therapeutic targets in the context of PsA and (2) the pleiotropic action of apremilast could make it an excellent choice for the management of PsA patients with high CVD risk, targeting metabolic alterations and CVD-related molecules
Multi-anti-parasitic activity of arylidene ketones and thiazolidene hydrazines against trypanosoma cruzi and Leishmania spp.
A series of fifty arylideneketones and thiazolidenehydrazines was evaluated against Leishmania infantum and Leishmania braziliensis. Furthermore, new simplified thiazolidenehydrazine derivatives were evaluated against Trypanosoma cruzi. The cytotoxicity of the active compounds on non-infected fibroblasts or macrophages was established in vitro to evaluate the selectivity of their anti-parasitic effects. Seven thiazolidenehydrazine derivatives and ten arylideneketones had good activity against the three parasites. The IC50 values for T. cruzi and Leishmania spp. ranged from 90 nM–25 μM. Eight compounds had multi-trypanocidal activity against T. cruzi and Leishmania spp. (the etiological agents of cutaneous and visceral forms). The selectivity of these active compounds was better than the three reference drugs: benznidazole, glucantime and miltefosine. They also had low toxicity when tested in vivo on zebrafish. Trying to understand the mechanism of action of these compounds, two possible molecular targets were investigated: triosephosphate isomerase and cruzipain. We also used a molecular stripping approach to elucidate the minimal structural requirements for their anti-T. cruzi activity
From vineyards to feedlots: a fund-flow scanning of sociometabolic transition in the Vallès County (Catalonia) 1860-1956-1999
We analyse the changes to agricultural metabolism in four municipalities of Vallès County (Catalonia, Iberia) by accounting for their agroecosystemfunds and flows during the socioecological transition from organic to industrial farming between the late nineteenth and twentieth centuries. The choice of three different stages in this transition allows us to observe the transformation of its funds and flows over time, the links established between them and the effect on their energy profiles.We emphasize the relevance of the integration and consistency of agroecosystem funds for energy efficiency in agriculture and their role as underlying historical drivers of this socioecological transition. While readjustment to market conditions and availability and affordability of external inputs are considered the main drivers of the transition, we also highlight the role of societal energy and nutritional transitions. An analysis of advanced organic agriculture c. 1860 reveals the great effort required to reproduce soil fertility and livestock from the internal recirculation of biomass. Meanwhile, a balance between land produce and livestock densities enabled the integration of funds, with a positive impact on energy performance. The adoption of fossil fuels and synthetic fertilizers c. 1956 reduced somewhat the pressure exerted on the land by overcoming the former dependence on local biomass flows to reproduce the agroecosystem. Yet external inputs diminished sustainability. Partial dependence on external markets existed congruently with internal crop diversity and the predominance of organic over industrial farm management. A shift towards animal production and consumption led to a new specialization process c. 1999 that resulted in crop homogenization and agroecological landscape disintegration. The energy returns of this linear feed-food livestock bioconversion declined compared to earlier mixed farming. Huge energy flows driven by a globalized economy ran through this agroecosystem, provoking deep impacts at both a local and external scale
Primera aproximación al uso de la ocupación del tapir (Tapirella bairdii Gill, 1865) como indicador de la integridad ecológica en la Reserva de la Biosfera Maya, Guatemala
La Reserva de la Biosfera Maya (RBM) es un área protegida de relevancia nacional, regional y mundial por la diversidad biológica asociada y los beneficios que se obtienen de esta. En su plan maestro se plantea el conjunto de elementos de conservación a partir de los cuales se orientan estrategias y se evalúa la efectividad de manejo de dicha reserva, entre los cuales se incluye a Tapirella bairdii (tapir), por lo que es importante contar con un monitoreo de esta especie como una herramienta para la administración de esta reserva. En el 2015 se inició el desarrollo de un protocolo de monitoreo basado en la estimación de la probabilidad de ocupación y el presente estudio constituye la continuación de esta iniciativa a través de la implementación de las temporadas de muestreo en 2017 y 2018. Se registró la presencia del tapir en cinco zonas núcleo de la RBM empleando trampas cámara y se estimó la probabilidad de ocupación. Los valores estimados sugieren una relación de la ocupación con la integridad ecológica, en la cual hay una mayor ocupación en áreas con menor perturbación. Se generaron modelos con cinco covariables relacionadas con amenazas potenciales, sin embargo fue el modelo nulo el que se seleccionó de acuerdo al criterio definido. Los resultados sugieren que la integridad ecológica en las áreas de estudio está siendo afectada como consecuencia de las presiones antrópicas por lo que es necesario el fortalecimiento de aquellas con menores valores de ocupación.
Plasma Androgen Receptor and Docetaxel for Metastatic Castration-resistant Prostate Cancer
Plasma androgen receptor (AR) gain identifies metastatic castration-resistant prostate cancer (mCRPC) patients with worse outcome on abiraterone/enzalutamide but its relevance in the context of taxane chemotherapy is unknown. We aimed to evaluate whether docetaxel is active regardless of plasma AR and to perform exploratory analysis to compare docetaxel with abiraterone/enzalutamide. This multi-institution study was a pooled analysis of AR status, determined by droplet digital PCR, on pre-treatment plasma samples. We evaluated associations between plasma AR and overall/progression-free survival (OS/PFS) and prostate-specific antigen (PSA) response rate in 163 docetaxel-treated patients. OS was significantly shorter in AR-gain [hazard ratio (HR)=1.61, 95% confidence interval (CI)=1.08-2.39, p=0.018), but not PFS (HR=1.04, 95%CI 0.74-1.46, p=0.8), nor PSA response [odds ratio (OR)=1.14, 95%CI=0.65-1.99, p=0.7)]. We investigated the interaction between plasma AR and treatment type after incorporating updated data from our prior study of 7 chemotherapy-naïve, abiraterone/enzalutamide-treated patients with data from 115 first-line docetaxel patients. In an exploratory analysis of mCRPC receiving first-line therapies, a significant interaction was observed between plasma AR and docetaxel versus abiraterone/enzalutamide for OS (HR=0.27,95%CI=0.11-0.68, p=0.005) and PFS (HR=0.28, 95%CI=0.12-0.64, p=0.002). Specifically, we reported a significant difference for OS favoring abiraterone/enzalutamide for AR-normal (HR=1.93, 95%CI=1.19-3.12, p=0.008) and a suggestion favoring docetaxel for AR-gained patients (HR=0.53, 95%CI=0.24-1.16, p=0.11). These data suggest that AR-normal patients should receive abiraterone/enzalutamide and AR-gained docetaxel. This treatment selection merits prospective evaluation in a randomized trial. // Patient summary:
We investigated whether plasma androgen receptor (AR) predicted outcome in metastatic castration-resistant prostate cancer (mCRPC) patients treated with docetaxel, and we performed an exploratory analysis in patients treated with docetaxel or AR-directed drugs as first-line mCRPC therapy. We showed that plasma AR normal favored hormonal treatment, whilst plasma AR-gained patients may have had a longer response to docetaxel, suggesting that plasma AR status could be a useful treatment selection biomarker
Vicariance and dispersal in southern hemisphere freshwater fish clades: a palaeontological perspective
Widespread fish clades that occur mainly or exclusively in fresh water represent a key target of biogeographical investigation due to limited potential for crossing marine barriers. Timescales for the origin and diversification of these groups are crucial tests of vicariant scenarios in which continental break‐ups shaped modern geographic distributions. Evolutionary chronologies are commonly estimated through node‐based palaeontological calibration of molecular phylogenies, but this approach ignores most of the temporal information encoded in the known fossil record of a given taxon. Here, we review the fossil record of freshwater fish clades with a distribution encompassing disjunct landmasses in the southern hemisphere. Palaeontologically derived temporal and geographic data were used to infer the plausible biogeographic processes that shaped the distribution of these clades. For seven extant clades with a relatively well‐known fossil record, we used the stratigraphic distribution of their fossils to estimate confidence intervals on their times of origin. To do this, we employed a Bayesian framework that considers non‐uniform preservation potential of freshwater fish fossils through time, as well as uncertainty in the absolute age of fossil horizons. We provide the following estimates for the origin times of these clades: Lepidosireniformes [125–95 million years ago (Ma)]; total‐group Osteoglossomorpha (207–167 Ma); Characiformes (120–95 Ma; a younger estimate of 97–75 Ma when controversial Cenomanian fossils are excluded); Galaxiidae (235–21 Ma); Cyprinodontiformes (80–67 Ma); Channidae (79–43 Ma); Percichthyidae (127–69 Ma). These dates are mostly congruent with published molecular timetree estimates, despite the use of semi‐independent data. Our reassessment of the biogeographic history of southern hemisphere freshwater fishes shows that long‐distance dispersals and regional extinctions can confound and erode pre‐existing vicariance‐driven patterns. It is probable that disjunct distributions in many extant groups result from complex biogeographic processes that took place during the Late Cretaceous and Cenozoic. Although long‐distance dispersals likely shaped the distributions of several freshwater fish clades, their exact mechanisms and their impact on broader macroevolutionary and ecological dynamics are still unclear and require further investigation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148368/1/brv12473_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148368/2/brv12473.pd
HE-LHC: The High-Energy Large Hadron Collider – Future Circular Collider Conceptual Design Report Volume 4
In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries
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