Celecoxib accelerates functional recovery after sciatic nerve crush in the rat

The inflammatory response appears to be essential in the modulation of the degeneration and regeneration process after peripheral nerve injury. In injured nerves, cyclooxygenase-2 (COX-2) is strongly upregulated around the injury site, possibly playing a role in the regulation of the inflammatory response. In this study we investigated the effect of celecoxib, a COX-2 inhibitor, on functional recovery after sciatic nerve crush in rats. Unilateral sciatic nerve crush injury was performed on 10 male Wistar rats. Animals on the experimental group (n = 5) received celecoxib (10 mg/kg ip) immediately before the crush injury and daily for 7 days after the injury. Control group (n = 5) received normal saline at equal regimen. A sham group (n = 5), where sciatic nerve was exposed but not crushed, was also evaluated. Functional recovery was then assessed by calculating the sciatic functional index (SFI) on days 0,1,7,14 and 21 in all groups, and registering the day of motor and walking onset. In comparison with control group, celecoxib treatment (experimental group) had significant beneficial effects on SFI, with a significantly better score on day 7. Anti-inflammatory drug celecoxib should be considered in the treatment of peripheral nerve injuries, but further studies are needed to explain the mechanism of its neuroprotective effects

Lessons from the operation of the "Penning-Fluorescent" TPC and prospects

We have recently reported the development of a new type of high-pressure Xenon time projection chamber operated with an ultra-low diffusion mixture and that simultaneously displays Penning effect and fluorescence in the near-visible region (300 nm). The concept, dubbed `Penning-Fluorescent' TPC, allows the simultaneous reconstruction of primary charge and scintillation with high topological and calorimetric fidelity

Transmission of Beauveria bassiana from male to female Aedes aegypti mosquitoes

<p>Abstract</p> <p>Background</p> <p>Resistance to chemical insecticides plus high morbidity rates have lead to rising interest in fungi as candidates for biocontrol agents of mosquito vectors. In most studies fungal infections have been induced by exposure of mosquitoes to various surfaces treated with conidia. In the present study eight Mexican strains of <it>Beauveria bassiana </it>were assessed against <it>Aedes aegypti </it>by direct exposure of females to 6 × 10⁸conidia ml ^-1on a filter paper, afterwards, the transmission of the least and most virulent isolates was evaluated by mating behavior from virgin, fungus-contaminated male to females, to examine this ethological pattern as a new approach to deliver conidia against the dengue vector.</p> <p>Methods</p> <p>In an exposure chamber with a filter paper impregnated with 6 × 10⁸conidia ml ^-1of the least and most virulent strains of <it>B. bassiana</it>, 6-8 day old males of <it>A. aegypti </it>were exposed for 48 hours, and then transferred individually (each one was a replicate) to another chamber and confined with twenty healthy females of the same age. Clean males were used in controls. Survival, infection by true mating (insemination) or by mating attempts (no insemination) and fecundity were daily registered until the death of last female. Data analysis was conducted with proc glm for unbalanced experiments and means were separated with the Ryan test with SAS.</p> <p>Results</p> <p>All strains were highly virulent with LT₅₀ranging from 2.70 (± 0.29) to 5.33 (± 0.53) days. However the most (Bb-CBG2) and least virulent (Bb-CBG4) isolates were also transmitted by mating behavior; both killed 78-90% of females in 15 days after being confined with males that had previously been exposed for 48 hours to fungi. Of these mortality rates, 23 and 38% respectively, were infections acquired by copulations where insemination occurred. The LT₅₀for sexually-infected females were 7.92 (± 0.46) and 8.82 (± 0.45) days for both strains, while the one in control was 13.92 (± 0.58). Likewise, fecundity decreased by 95% and 60% for both Bb-CBG2 and Bb-CBG4 isolates in comparison with control. The role of mating attempts in this delivery procedure of <it>B. bassiana </it>is discussed.</p> <p>Conclusions</p> <p>This is the first report about transmission of <it>B. bassiana </it>by mating behavior from virgin, fungus-contaminated males to females in <it>A. aegypti</it>. Fungal infections acquired by this route (autodissemination) infringed high mortality rates (90%) in mated or approached females. However, prior to releasing virgin, fungus-contaminated males to spread <it>B. basasiana </it>among females of <it>A. aegypti</it>, this novel alternative needs further investigations.</p

Infancia y flexibilidad laboral en la agricultura de exportación mexicana

Desde mediados de los ochenta del siglo pasado, la reducción del gasto público destinado al campo y la eliminación de barreras comerciales pusieron en juego la competitividad del sector agrícola mexicano. Las empresas adoptaron cambios tecnológicos y de organización laboral a partir de una combinación de mano de obra calificada con fuerza de trabajo desvalorizada por razones de género, edad o etnia; esta última opera en condiciones de amplia flexibilidad laboral. El presente artículo analiza las formas de inserción del trabajo infantil migrante en la agricultura de exportación mexicana. Los datos fueron levantados en un campo de jornaleros de una de las empresas más importantes del ramo. Se aplicó una encuesta a 66 familias y se hicieron 41 entrevistas semi-estructuradas, 3 talleres con infantes y una matriz de riesgos laborales. El 94% de los niños y niñas trabajan en el corte de pepino y jitomate y el 6% restante (chicas mayores de 14 años) en labores de empaque. Las niñas presentan una doble jornada de trabajo debido a sus responsabilidades domésticas. El ingreso promedio diario es de 97 pesos mexicanos (alrededor de $9.40 dólares de los EE. UU.), que contribuye a cerca de la mitad del ingreso global de la familia. Se concluye que el derecho a la educación y a la salud de la población infantil jornalera son los más afectados, ya que dos tercios de los niños y niñas encuestados no asisten a la escuela y sus condiciones de trabajo conllevan considerables riesgos para la salud.-1. Introducción. -2. Diseño metodológico. -3. Marco conceptual: flexibilidad laboral y trabajo infantil. -4. Flexibilidad laboral y trabajo infantil jornalero. -4.1. Eventualidad en el empleo. -4.2. Jornada laboral.-4.3. Forma de contratación y pago. -4.4. Riesgos para la salud. -5. Conclusiones. -Bibliografí

Known by the company we keep: `Triadic influence' as a proxy for compatibility in social relationships

Networks of social interactions are the substrate upon which civilizations are built. Often, we create new bonds with people that we like or feel that our relationships are damaged through the intervention of third parties. Despite their importance and the huge impact that these processes have in our lives, quantitative scientific understanding of them is still in its infancy, mainly due to the difficulty of collecting large datasets of social networks including individual attributes. In this work, we present a thorough study of real social networks of 13 schools, with more than 3,000 students and 60,000 declared positive and negative relations, including tests for personal traits of all the students. We introduce a metric -- the `triadic influence' -- that measures the influence of nearest-neighbors in the relationships of their contacts. We use neural networks to predict the relationships and to extract the probability that two students are friends or enemies depending on their personal attributes or the triadic influence. We alternatively use a high-dimensional embedding of the network structure to also predict the relationships. Remarkably, the triadic influence (a simple one-dimensional metric) achieves the highest accuracy at predicting the relationship between two students. We postulate that the probabilities extracted from the neural networks -- functions of the triadic influence and the personalities of the students -- control the evolution of real social networks, opening a new avenue for the quantitative study of these systems

Aflatoxin M Determination in Infant Formulae Distributed in Monterrey, Mexico

The occurrence of aflatoxin M (AFM) in infant formulae commercialized in the metropolitan area of Monterrey (Nuevo León, Mexico) was determined by using immunoaffinity column clean-up followed by HPLC determination with fluorimetric detection. For this, 55 infant formula powders were classified in two groups, starter (49 samples) and follow-on (6 samples) formulae. Eleven of the evaluated samples (20%) presented values above the permissible limit set by the European Union for infant formulae (25 ng/L), ranging from 40 to 450 ng/L. The estimated daily intake (EDI) for AFM was determined employing the average body weight (bw) of the groups of age in the ranges of 0-6 and 6-12 months, and 1-2 years. The results evidenced high intake values, ranging from 1.56 to 14 ng/kg bw/day, depending on the group. Finally, with the EDI value, the carcinogenic risk index was determined, presenting a high risk for all the evaluated groups. Based on these results, it is a necessary extra effort by the regulatory agencies to reduce the AFM presence in infant formulae consumed in Mexico

Gaseous time projection chambers for rare event detection: Results from the T-REX project. II. Dark matter

As part of the T-REX project, a number of R&D and prototyping activities have been carried out during the last years to explore the applicability of Micromegas-read gaseous TPCs in rare event searches like double beta decay (DBD), axion research and low-mass WIMP searches. While in the companion paper we focus on DBD, in this paper we focus on the results regarding the search for dark matter candidates, both axions and WIMPs. Small ultra-low background Micromegas detectors are used to image the x-ray signal expected in axion helioscopes like CAST at CERN. Background levels as low as $0.8\times 10^{-6}$ c keV$^{-1}$cm$^{-2}$s$^{-1}$ have already been achieved in CAST while values down to $\sim10^{-7}$ c keV$^{-1}$cm$^{-2}$s$^{-1}$ have been obtained in a test bench placed underground in the Laboratorio Subterr\'aneo de Canfranc. Prospects to consolidate and further reduce these values down to $\sim10^{-8}$ c keV$^{-1}$cm$^{-2}$s$^{-1}$will be described. Such detectors, placed at the focal point of x-ray telescopes in the future IAXO experiment, would allow for 10$^5$ better signal-to-noise ratio than CAST, and search for solar axions with $g_{a\gamma}$ down to few 10$^{12}$ GeV$^{-1}$, well into unexplored axion parameter space. In addition, a scaled-up version of these TPCs, properly shielded and placed underground, can be competitive in the search for low-mass WIMPs. The TREX-DM prototype, with $\sim$0.300 kg of Ar at 10 bar, or alternatively $\sim$0.160 kg of Ne at 10 bar, and energy threshold well below 1 keV, has been built to test this concept. We will describe the main technical solutions developed, as well as the results from the commissioning phase on surface. The anticipated sensitivity of this technique might reach $\sim10^{-44}$ cm$^2$ for low mass ($<10$ GeV) WIMPs, well beyond current experimental limits in this mass range.Comment: Published in JCAP. New version with erratum incorporated (new figure 14

“CLUPS”: A New Culture Medium for the Axenic Growth of Entamoeba histolytica

Amebiasis remains a major health problem in Mexico. Terefore, the search for better culture media and low-cost diagnostic and therapeutic tools is fundamental. We present a new culture medium for Entamoeba histolytica which allows the microbe to preserve its virulence factors and ability to induce hepatic abscesses in animal models. Te novel CLUPS medium is an improved version of the PEHPS medium, previously designed in our laboratory. Te main diference is the substitution of raw beef liver in PEHPS by raw beef lung in the CLUPS medium. To compare the performance of three-culture media (traditional TYI-S-33, PEHPS, and CLUPS), E. histolytica trophozoites were cultured in quintuplicate, followed by the evaluation of phospholipase activity and the induction of liver abscesses in golden hamsters. E. histolytica trophozoites grew signifcantly better in CLUPS medium than in TYIS-33. Likewise, CLUPS-cultured trophozoites produced signifcantly more phospholipases than TYI-S-33-cultured trophozoites. Finally, trophozoites grown in any of the three tested media had similar potential to induce liver abscesse

CAST microbulk micromegas in the Canfranc Underground Laboratory

During the last taking data campaigns of the CAST experiment, the micromegas detectors have achieved background levels of $\approx 5 \times 10^{-6}$keV$^{-1}$cm$^{-2}$s$^{-1}$ between 2 and 9 keV. This performance has been possible thanks to the introduction of the microbulk technology, the implementation of a shielding and the development of discrimination algorithms. It has motivated new studies towards a deeper understanding of CAST detectors background. One of the working lines includes the construction of a replica of the set-up used in CAST by micromegas detectors and its installation in the Canfranc Underground Laboratory. Thanks to the comparison between the performance of the detectors underground and at surface, shielding upgrades, etc, different contributions to the detectors background have been evaluated. In particular, an upper limit $< 2 \times 10^{-7}$keV$^{-1}$cm$^{-2}$s$^{-1}$ for the intrinsic background of the detector has been obtained. This work means a first evaluation of the potential of the newest micromegas technology in an underground laboratory, the most suitable environment for Rare Event Searches.Comment: 6 pages, 8 figures. To appear in the proceedings of the 2nd International Conference on Technology and Instrumentation for Particle Physics (TIPP 2011