Uprolides N, O and P from the Panamanian Octocoral Eunicea succinea.

Three new diterpenes, uprolide N (1), uprolide O (2), uprolide P (3) and a known one, dolabellane (4), were isolated from the CH₂Cl₂-MeOH extract of the gorgonian octocoral Eunicea succinea, collected from Bocas del Toro, on the Caribbean coast of Panama. Their structures were determined using spectroscopic analyses, including 1D and 2D NMR and high-resolution mass spectrometry (HRMS) together with molecular modeling studies. Compounds 1-3 displayed anti-inflammatory properties by inhibiting production of Tumor Necrosis Factor (TNF) and Interleukin (IL)-6 induced by lipopolysaccharide (LPS) in murine macrophages

Behavior of tumors under nonstationary theraphy

We present a model for the interaction dynamics of lymphocytes-tumor cells population. This model reproduces all known states for the tumor. Futherly,we develop it taking into account periodical immunotheraphy treatment with cytokines alone. A detailed analysis for the evolution of tumor cells as a function of frecuency and theraphy burden applied for the periodical treatment is carried out. Certain threshold values for the frecuency and applied doses are derived from this analysis. So it seems possible to control and reduce the growth of the tumor. Also, constant values for cytokines doses seems to be a succesful treatment.Comment: 6 pages, 7 figure

Quantum gravity, space-time structure, and cosmology

A set of diverse but mutually consistent results obtained in different settings has spawned a new view of loop quantum gravity and its physical implications, based on the interplay of operator calculations and effective theory: Quantum corrections modify, but do not destroy, space-time and the notion of covariance. Potentially observable effects much more promising than those of higher-curvature effective actions result; loop quantum gravity has turned into a falsifiable framework, with interesting ingredients for new cosmic world views. At Planckian densities, space-time disappears and is replaced by 4-dimensional space without evolution.Comment: 8 pages, 7 figures, Plenary talk at CosGrav12, held at Indian Statistical Institute, Kolkat

Edible Ectomycorrhizal Mushrooms: A Non-Timber Forest Product of Neotropical Forests and its Relation to Sustainability and Climate Change Mitigation

Edible ectomycorrhizal mushrooms (EEM) are a non-timber forest product that constitutes a valuable genetic resource and a nutritious and functional food containing antitumor, antidiabetes, antimicrobial, antihypertensive and antioxidant bioactive compounds, whose sustainable use can contribute to conservation of Neotropical forests. International commerce of some EEM annually is worth billions of dollars, while numerous EEM species represent a valuable food resource and an important source of income for thousands of families in countries with developing economies. Additionally, EEM can be used as biofertilizers which increase nutrient mobilization, health and survival of trees, therefore contributing to successful reforestations. The cultivation of some species of EEM has already been achieved, as in the case of the black truffles in Europe, while efforts in order to cultivate other species currently is being developed in different countries. During the last two decades, ethnomycological and biotechnological research registering EEM consumed in Mexico and selecting species feasible to inoculate Neotropical trees has been conducted by the authors. More than 250 EEM species have been recorded to be consumed as traditional food by 23 ethnic groups in the country; accounting for the second largest biodiversity of EEM worldwide, only after China. The sustainable use of EEM constitutes an important component of forest management, particularly in Neotropical areas with high degree of economic and social margination. Additionally, 25 species of EEM have been tested by the authors e.g. Laccaria, Hebeloma and Suillus species showing increased macro-(N, P, K, Ca and Mg) and micro-(Fe and Ca) nutrient mobilization, photosynthetic rate and chlorophyll a, b and total contents of inoculated plants compared with non-inoculated plants. Conspicuous ectomycorrhizal colonization, up to 100% in some cases, and production of EEM sporomes with 20 tested pine and oak species have demonstrated the feasibility of this biotechnology. Field trials developed in both low- and high-fertility soils have demonstrated increases in the survival of native inoculated pines and oaks; and initial production of EEM sporomes four years after the establishment of tree plantations has occurred. Molecular and metagenomic sequencing of the rRNA S1 and S18 genes studies conducted by the authors, have shown the persistence of the inoculated EEM and conspicuous changes in the microbiomes associated with mycorrhized and non-mycorrized root trees, respectively. This biotechnology has shown to increase natural production of EEM, demonstrating benefits to sustainable ecosystem management and, through successful reforestations, to mitigation of climate change.Keywords: Biodiversity conservation, Edible wild mushrooms, Ectomycorrhiza, Non-timber forest products, Environmental sustainabilit

Practical study of optical stellar interferometry

In this work we present an observational technique and a detailed analysis of the stellar interferograms produced by three bright stars: Betelgeuse, Rigel and Sirius. It is shown that the atmospheric turbulence is responsible for the reduction of the long-exposure fringe visibility of the obtained interference patterns. By using different baselines in our interferometer, we are able to distinguish the decay of the visibility with the baseline, how different parameters such us the diameter of the holes in our interferometer or their distribution affects the pattern, and to measure the turbulence with the estimation of the Fried parameter r0. The work and methodology are presented as a method for postgraduate students that targets practical learning of optical interferometry in astronomy and how it is affected by several causes, such as the atmospheric turbulence.Comment: 11 pages, 6 figures, paper submitted and accepted to AJ

A no-singularity scenario in loop quantum gravity

Canonical methods allow the derivation of effective gravitational actions from the behavior of space-time deformations reflecting general covariance. With quantum effects, the deformations and correspondingly the effective actions change, revealing dynamical implications of quantum corrections. A new systematic way of expanding these actions is introduced showing as a first result that inverse-triad corrections of loop quantum gravity simplify the asymptotic dynamics near a spacelike collapse singularity. By generic quantum effects, the singularity is removed.Comment: 10 page

Synthesis and Characterization of Multilayered CrAlN/Al2O3 Tandem Coating Using HiPIMS for Solar Selective Applications at High Temperature

The effect of applying a negative bias during deposition of a previously designed multilayer solar selective absorber coating was studied on two types of substrates (316L stainless steel and Inconel 625). The solar selective coating is composed of different chromium aluminum nitride layers deposited using a combination of radiofrequency (RF), direct current (DC), and high-power impulse magnetron sputtering (HiPIMS) technologies. The chemical composition is varied to generate an infrared reflective/absorber layer (with low Al addition and N vacancies) and two CrAlN intermediate layers with medium and high aluminum content (Al/Cr = 0.6 and 1.2). A top aluminum oxide layer (Al2O3) is deposited as an antireflective layer. In this work, a simultaneous DC-pulsed bias (−100 V, 250 kHz) was applied to the substrates in order to increase the film density. The optical performance, thermal stability, and oxidation resistance was evaluated and compared with the performance obtained with similar unbiased coating and a commercial Pyromark paint reference at 600, 700, and 800 °C. The coating remained stable after 200 h of annealing at 600 °C, with solar absorptance (α) values of 93% and 92% for samples deposited on stainless steel and Inconel, respectively, and a thermal emittance ϵ25°C of 18%. The introduction of additional ion bombardment during film growth through bias assistance resulted in increased durability, thermal stability, and working temperature limits compared with unbiased coatings. The solar-to-mechanical energy conversion efficiency at 800 °C was found to be up to 2 times higher than Pyromark at C = 100 and comparable at C = 1000

The cDNA and deduced amino acid sequence of the γ subunit of the L-type calcium channel from rabbit skeletal muscle

Complementary DNAs for the γ subunit of the calcium channel of rabbit skeletal muscle were isolated on the basis of peptide sequences derived from the purified protein. The deduced primary structure is without homology to other known protein sequences and is consistent with the γ subunit being an integral membrane protein