FIRST EVIDENCE OF THE TICKICIDE EFFECT OF ENTOMOPATHOGENIC FUNGI ISOLATED FROM MEXICAN CATTLE FARMS AGAINST AMBLYOMMA MIXTUM.

This is the first study to empirically evaluate the mortality of Amblyomma mixtum larvae caused by native entomopathogenic fungi (EPF) from cattle farm soils and the impact of the physicochemical conditions of those soils on the ability of EPF to kill ticks. The efficacy of 25 EPF strains isolated from cattle farms soils in Veracruz, Mexico, against A. mixtum ticks was evaluated using a larval immersion test. Physicochemical analyses of the soils where the EPF were isolated were carried out, and the results were correlated with the obtained mortality. The MaV25 strain showed a mortality of 36.55% (P < 0.05), followed by MaV57 with 27.30%, MaV08 with 26.21%, and MaV31 with 24.32% (P < 0.05). Nitrogen and potassium are nutritional components of soils that seem to be associated with mortality caused by the evaluated fungal strains. This is the first study in Mexico where the effect of EPF against A. mixtum is evaluated and also is the first study in the world that uses native strains from livestock soils against larvae of this tick. It is necessary to determine the virulence characteristics of EPF on A. mixtum to improve knowledge of fungus-tick interactions (Metarhizium anisopliae-A. mixtum).

Collective dynamics of liquid sulfur scrutinized over three decades in frequency.

Liquid sulfur consists mainly of eight-membered rings and hence can be regarded as a model of a molecular liquid. A liquid, which is built from different molecular structures, will demonstrate a wide range in relaxation processes and excitation modes. Three inelastic neutron scattering experiments have been performed to study the collective dynamics of liquid sulfur over three decades in frequencies. A wide range of wave vectors was studied to reveal the response of density fluctuations over different lengthscales. A viscoelastic model with a two-times memory function was applied to the data. The analysis revealed a slow relaxation mode, an acoustic-type excitation, and a high-frequency mode, which resembles an optic-type excitation. The wave-vector dependence of the slow relaxation mode width exhibits the signs of a de Gennes narrowing around the wave vector where the structure factor has a shoulder. This slow relaxation process could be related to diffusive particle movements. The acoustic-type modes evidence a viscoelastic reaction with a 50% enhancement of the sound velocity. This enhancement of the sound velocity and the spectral line shape is qualitatively similar to spectra of molecular liquids. The two relaxation times of the memory function are separated by about two orders of magnitude and underpin the need for a wide frequency range investigation of this complex liquid. The high-frequency response can be interpreted as optic-type modes in the liquid.

Determination of the vibrational contribution to the entropy change at the martensitic transformation in Ni-Mn-Sn metamagnetic shape memory alloys: a combined approach of time-of-flight neutron spectroscopy and ab initio calculations.

The different contributions to the entropy change linked to the austenite-martensitic transition in a Ni-Mn-Sn metamagnetic shape memory alloy have been determined by combining different experimental techniques. The vibrational contribution has been inferred from the vibrational density of states of both the martensitic and austenite phases. This has been accomplished by combining time-of-flight neutron scattering measurements and ab initio calculations. Further, the electronic part of the entropy change has also been calculated. Since the martensitic transformation takes place between two paramagnetic phases, the magnetic contribution can be neglected and the entropy change can be reduced to the sum of two terms: vibrational and electronic. The obtained value of the vibrational contribution ([Formula: see text]) nearly provides the total entropy change measured by calorimetry ([Formula: see text]), the difference being the electronic contribution within the experimental error.

Anisotropy on the collective dynamics of water confined in swelling clay minerals.

Collective excitations of water confined in the interlayer space of swelling clay minerals were studied by means of inelastic neutron scattering. The effect of bidimensional confinement on the dynamics of the interlayer water was investigated by using a synthetic Na-saponite sample with a general formula of Si(7.3)Al(0.7)Mg(6)O(20)(OH)(4)Na(0.7) in a bilayer hydration state. Experimental results reveal two inelastic signals, different from those described for bulk water with a clear anisotropy on the low-energy excitation of the collective dynamics of interlayer water, this difference being stronger in the perpendicular direction. Results obtained for the parallel direction follow the same trend as bulk water, and the effect of the confinement is mainly manifested from the fact that clay interlayer water is more structured than bulk water. Data obtained in the perpendicular direction display a nondispersive behavior below a cutoff wavenumber value, Q(c), indicating a nonpropagative excitation below that value. Molecular dynamics simulations results agree qualitatively with the experimental results.

Anomalous magnetic excitations of cooperative tetrahedral spin clusters.

An inelastic neutron scattering study of Cu2Te2O5X2 (X=Cl, Br) shows strong dispersive modes with large energy gaps persisting far above TN, notably in Cu2Te2O5Br2. The anomalous features: a coexisting unusually weak Goldstone-like mode observed in Cu2Te2O5Cl2 and the size of the energy gaps cannot be explained by existing theories, such as our mean-field or random-phase approximation. We argue that our findings represent a new general type of behavior due to intercluster quantum fluctuations and call for development of a new theoretical approach.

Material de seguridad para cateterización periférica venosa / Security material for venous peripheral. Catheterization evaluation in an emergency ward

La canalización venosa puede ser uno de los motivos másfrecuentes de accidentes por punción accidental. La realizaciónde actividades encaminadas a disminuir estos percances,de elevado riesgo biológico, debe ser una prioridad paralas instituciones sanitarias y para sus profesionales. Dentrode una estrategia global que incida en este aspecto y con elobjetivo de evaluar la idoneidad de estos dispositivos ennuestro centro, se realiza una valoración práctica de unaserie de ellos para conocer su viabilidad técnica y la apreciaciónsubjetiva de los profesionales que los prueben. Pormotivos relacionados con las prácticas del servicio en el quese desarrolla la investigación (Servicio de Urgencias), seseleccionan intencionalmente dos dispositivos pasivos,disponibles en el mercado, y tres enfermeros, que recibieron120 muestras de catéteres de seguridad (60 del producto A,60 del producto B) para realizar las prácticas clínicas habituales,junto con una hoja de incidencias. Con respecto aldispositivo A, se detectaron 30 incidencias (52,6%) y seprocedió a toma de muestras en 37 ocasiones. Con respectoal dispositivo B, se detectaron cuatro incidencias (7,01%)y se procedió a la toma de muestras en 47 ocasiones. En términosabsolutos, ninguno de los dos dispositivos ha mostradoproblemas con la práctica segura, es decir, no han provocadoincidencias relacionadas con la aparición de percancesasociados a punciones accidentales. La menor frecuencia deincidencias en el dispositivo B parece estar relacionada con eluso habitual del catéter convencional (no de seguridad) delmismo fabricante en nuestro centro. Trabajo subvencionadopor el Fondo de Investigaciones Sanitarias. PI 051265(AU)

Venous canalization can be one of the most frequent causesof accidents due to an accidental puncture. To carry out activitieswhich serve to lessen these misfortunes, bearing highbiological risk, should become a priority for sanitary institutionsand for their professionals. Inside a global strategywhich deals with this aspect and with the objective of evaluatingthe convenience these instruments have in our center,the authors made a practical evaluation on a series of themto discover their technical viability and their subjective considerationby professionals who employ them. For motives relatedto the practices of the ward in which this research tookplace, an emergency ward, the authors intentionally chosetwo passive instruments, available on the market, and threenurses who received 120 sample security catheters, 60 eachfor products A and B, to carry out habitual clinical practices,alongside a pad of paper on which to record any incidents.Regarding instrument A, 30 incidents, 52.6%, were detectedwhile 37 sample procedures occurred. Regarding instrumentB, 4 incidents, 7.01%, were detected while 47 sample proceduresoccurred. In absolute terms, neither of the two instrumentsdemonstrated problems of an insecure manner; whichis to say, neither produced a situation related to the appearanceof misfortunate incidents associated to accidentalpunctures. The lower number of incidents with instrument Bappears to be related to the habitual use of a conventionalcatheter, not a security one, produced by the same manufacturerin our center. This research project was subsidized bythe Sanitary Research Fund, PI 051265(AU)

Unconventional density dependence of the stochastic dynamics in an organic liquid.

The density dependence of the diffusive rotational and center-of-mass dynamics of 2-methyl-pyridine is investigated by means of the concurrent use of quasielastic neutron scattering and molecular dynamics simulations. The dependence of both translation and rotational diffusion coefficients shows a distinctive change of slope with increasing density taking place about rho=0.975 g/cm3. Such a change in the dynamics can be related to observations made in other liquids composed of oblate-spheroidal particles.

Molecular approach to the interpretation of the dielectric relaxation spectrum of a molecular glass former

The frequency-dependent dielectric function of ethanol at temperatures within the normal liquid range is evaluated by means of computer molecular dynamics simulations and compared with recent experimental data. The calculated spectra show a similar structure to those reported from experimental measurements and the temperature dependence of its most prominent bands also follows the experimental estimates. An attempt is also made to assign the most intense bands to specific molecular reorientations.