Antimicrobial activity of Bursera morelensis ramírez essential oil

Background: Bursera morelensis, known as “Aceitillo”, is an endemic tree of Mexico. Infusions made from the bark of this species have been used for the treatment of skin infections and for their wound healing properties. In this work, we present the results of a phytochemical and antimicrobial investigation of the essential oil of B. morelensis.Materials and Methods: The essential oil was obtained by a steam distillation method and analyzed using GC-MS. The antibacterial and antifungal activities were evaluated.Results: GC-MS of the essential oil demonstrated the presence of 28 compounds. The principal compound of the essential oil was α-Phellandrene (32.69%). The essential oil had antibacterial activity against Gram positive and negative strains. The most sensitive strains were S. pneumoniae, V. cholerae (cc) and E. coli (MIC 0.125 mg/mL, MBC 0.25 mg/mL). The essential oil was bactericidal for V. cholera (cc). The essential oil inhibited all the filamentous fungi. F. monilifome (IC50 = 2.27 mg/mL) was the most sensitive fungal strain.Conclusions: This work provides evidence that confirms the antimicrobial activity of the B. morelensis essential oil and this is a scientific support about of traditional uses of this species.Keywords: Essential oil; Medicinal plants; Tehuacan-Cuicatlan Valley; Burseraceae; Burser

HyperCP: A high-rate spectrometer for the study of charged hyperon and kaon decays

The HyperCP experiment (Fermilab E871) was designed to search for rare phenomena in the decays of charged strange particles, in particular CP violation in $\Xi$ and $\Lambda$ hyperon decays with a sensitivity of $10^{-4}$. Intense charged secondary beams were produced by 800 GeV/c protons and momentum-selected by a magnetic channel. Decay products were detected in a large-acceptance, high-rate magnetic spectrometer using multiwire proportional chambers, trigger hodoscopes, a hadronic calorimeter, and a muon-detection system. Nearly identical acceptances and efficiencies for hyperons and antihyperons decaying within an evacuated volume were achieved by reversing the polarities of the channel and spectrometer magnets. A high-rate data-acquisition system enabled 231 billion events to be recorded in twelve months of data-taking.Comment: 107 pages, 45 Postscript figures, 14 tables, Elsevier LaTeX, submitted to Nucl. Instrum. Meth.

Asymmetric nuclear matter:the role of the isovector scalar channel

We try to single out some qualitative new effects of the coupling to the $\delta$-isovector-scalar meson introduced in a minimal way in a phenomenological hadronic field theory. Results for the equation of state ($EOS$) and the phase diagram of asymmetric nuclear matter ($ANM$) are discussed. We stress the consistency of the $\delta$-coupling introduction in a relativistic approach. New contributions to the slope and curvature of the symmetry energy and the neutron-proton effective mass splitting appear particularly interesting. A more repulsive $EOS$ for neutron matter at high baryon densities is expected. Effects on new critical properties of warm $ANM$, mixing of mechanical and chemical instabilities and isospin distillation, are also presented. The $\delta$ influence is mostly on the {\it isovectorlike} collective response. The results are largely analytical and this makes the physical meaning quite transparent. Implications for nuclear structure properties of drip-line nuclei and for reaction dynamics with Radioactive Beams are finally pointed out.Comment: 12 pages, 10 Postscript figure

Economical and technological study of surface grinding versus face milling in hardened AISI D3 steel machining operations

[EN] This work deals with the technological and economic considerations required to select face milling vs. surface grinding operations in the manufacture of hardened steel flat surfaces for dies and moulds. In terms of technological considerations, factors such as component geometry, material and surface quality (dimensional tolerance and surface finish) are taken into account. The economic considerations include the cost of machine depreciation, labour and consumables (cutting tools in face milling vs. grinding wheels and dressing tool in surface grinding). A case study is presented based on the prismatic components in ceramic tile moulds and their associated manufacturing operations. Surface grinding and face milling experimentation was conducted on cold work steel AISI D3 (with hardness of 60 HRC) with aluminium oxide grinding wheels and coated tungsten carbide cutting tool, respectively. Technological attributes and economics of face milling are compared with surface grinding of this type of mould components. The main conclusion is that face milling with chamfered edge preparation in coated tungsten carbide tools is a competitive process, compared with surface grinding, in terms of product quality and economics.The research team would like to acknowledge the main support of the Caja Castello-Bancaixa Foundation and Universitat Jaume I, which support the project: "Integration of Planning, Execution and Control of High Speed Machining Operations in Collaborative Engineering Environments: Application in Moulds for Tile Industry", the ceramic tile mould company MACER S.L., and would like to extend their gratitude to Roberto Menendez, student of industrial engineering. Particular thanks go to the Programme Alssan: European Union Programme of High Level Scholarships for Latin America (scholarship no. E04D030982MX). Additional support was provided by Tecnologico de Monterrey through the research group in Mechatronics and Intelligent Machines (http://cidyt.mty.itesm/cimec).Vila Pastor, C.; Siller, H.; Rodríguez, C.; Bruscas Bellido, G.; Serrano, J. (2012). Economical and technological study of surface grinding versus face milling in hardened AISI D3 steel machining operations. International Journal of Production Economics. 138(2):273-283. doi:10.1016/j.ijpe.2012.03.028S273283138

Adsorption of mono- and multivalent cat- and anions on DNA molecules

Adsorption of monovalent and multivalent cat- and anions on a deoxyribose nucleic acid (DNA) molecule from a salt solution is investigated by computer simulation. The ions are modelled as charged hard spheres, the DNA molecule as a point charge pattern following the double-helical phosphate strands. The geometrical shape of the DNA molecules is modelled on different levels ranging from a simple cylindrical shape to structured models which include the major and minor grooves between the phosphate strands. The densities of the ions adsorbed on the phosphate strands, in the major and in the minor grooves are calculated. First, we find that the adsorption pattern on the DNA surface depends strongly on its geometrical shape: counterions adsorb preferentially along the phosphate strands for a cylindrical model shape, but in the minor groove for a geometrically structured model. Second, we find that an addition of monovalent salt ions results in an increase of the charge density in the minor groove while the total charge density of ions adsorbed in the major groove stays unchanged. The adsorbed ion densities are highly structured along the minor groove while they are almost smeared along the major groove. Furthermore, for a fixed amount of added salt, the major groove cationic charge is independent on the counterion valency. For increasing salt concentration the major groove is neutralized while the total charge adsorbed in the minor groove is constant. DNA overcharging is detected for multivalent salt. Simulations for a larger ion radii, which mimic the effect of the ion hydration, indicate an increased adsorbtion of cations in the major groove.Comment: 34 pages with 14 figure

The Risk of Contracting COVID-19 Is Not Increased in Patients With Celiac Disease

The World Health Organization declared coronavirus disease-2019 (COVID-19) a global pandemic in March 2020. Since then, there are more than 34 million cases of COVID-19 leading to more than 1 million deaths worldwide. Numerous studies suggest that celiac disease (CeD), a chronic immune-mediated gastrointestinal condition triggered by gluten, is associated with an increased risk of respiratory infections.1-3 However, how it relates to the risk of COVID-19 is unknown. To address this gap, we conducted a cross-sectional study to evaluate whether patients with self-reported CeD are at an increased risk of contracting COVID-19

Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{$6\times 10^{19}$eV}. The anisotropy was measured by the fraction of arrival directions that are less than $3.1^\circ$ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron $12^{\rm th}$ catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is $(38^{+7}_{-6})$, compared with $21$ expected for isotropic cosmic rays. This is down from the early estimate of $(69^{+11}_{-13})$. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201