METHYLATION OF E. COLI TRANSFER RIBONUCLEIC ACIDS BY A tRNA ADENINE-l-METHYLTRANSFERASE FROM RAT BRAIN CORTEX AND BULK-ISOLATED NEURONS

Brain cortices or bulk-isolated neuronal cell bodies prepared from cortices of 8-day old male rats were used as the source of a l-methyl adenine-specific tRNA methyltransferase (tRNA-AMT). Ammonium sulfate fractionation and chromatography on spheroidal hydroxylapatite and Sephadex G-200 yielded an 80-fold purified enzyme, as determined by using E. coli bulk tRNA as substrate. The kinetic parameters of tRNA-AMT for the substrate S -adenosyl-l-methionine (SAM) ( K m = 6 ΜM) and the inhibitor, S -adenosyl-l-homocysteine (SAH) ( K i = 3.4 Μm) were determined and several SAH analogs tested as inhibitors. S -Adenosyl-l-cysteine (SAC) ( 10 -4 m) and S -adenosyl-d-homocysteine (SADH) (10 -4 m) produced a 35 and a 21% reduction in enzyme activity, respectively. The effects of Mg 2+ , NH 4 + acetate and of the polyamines spermine, putrescine and spermidine on the brain tRNA-AMT mimicked the effects of these agents on hepatic tRNA-AMT (Glick et al , 1975). Comparing the ability of cerebral tRNA-AMT to methylate E. coli tRNA glu2 , tRNA val , tRNA phe and bulk tRNA revealed tRNA glu2 as the best and tRNA phe as the least effective substrate. tRNA-AMT prepared from neuronal cell bodies showed closely similar characteristics to the cortical enzyme. A comparison of the activities of tRNA-AMT in neurons and glial cells revealed higher values in the former.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66287/1/j.1471-4159.1978.tb12436.x.pd

Diphyllobothrium sp. en Canis familiaris de la región del subtrópico argentino (Puerto Iguazú, Misiones)

This paper reports the first finding of Diphyllobothrium sp. eggs in Canis familiaris(domestic dog) from Puerto Iguazú, a subtropical city of Misiones province, Argentina. In 2013,two positive cases of Diphyllobothrium sp. eggs were detected during an annual parasitological survey of dogs. Dog feces were collected in vials containing 10 % formalin and processed using Telemann?s sedimentation and Sheather?s flotation techniques. The two cases were detected in rural areas of the municipality. Since Misiones is not a part of the endemic area of diphyllobothriasis and given the fact that it is located in the three-border area of Argentina, Brazil and Paraguay, we consider this finding of great importance to public health. We stress the need for updating the current knowledge about the life cycle of these parasites considering the range of intermediate and definitive hosts, their zoonotic potential, and the epidemiological situation in non-endemic areas.This paper reports the first finding of Diphyllobothrium sp. eggs in Canis familiaris (domestic dog) from Puerto Iguazú, a subtropical city of Misiones province, Argentina. In 2013, two positive cases of Diphyllobothrium sp. eggs were detected during an annual parasitological survey of dogs. Dog feces were collected in vials containing 10 % formalin and processed using Telemann's sedimentation and Sheather's flotation techniques. The two cases were detected in rural areas of the municipality. Since Misiones is not a part of the endemic area of diphyllobothriasis and given the fact that it is located in the three-border area of Argentina, Brazil and Paraguay, we consider this finding of great importance to public health. We stress the need for updating the current knowledge about the life cycle of these parasites considering the range of intermediate and definitive hosts, their zoonotic potential, and the epidemiological situation in non-endemic areas.Fil: Rivero, Maria Romina. Ministerio de Salud. Instituto Nacional de Medicina Tropical; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Motta, Carlos E.. Universidad Nacional de Rio Cuarto. Facultad de Agronomia y Veterinaria. Departamento de Patología Animal; ArgentinaFil: Salas, Martin Miguel. Ministerio de Salud. Instituto Nacional de Medicina Tropical; ArgentinaFil: Chiaretta, Alicia. Universidad Nacional de Rio Cuarto. Facultad de Agronomia y Veterinaria. Departamento de Patología Animal; ArgentinaFil: Salomón, Oscar Daniel. Ministerio de Salud. Instituto Nacional de Medicina Tropical; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Guided wave structural health monitoring using CLoVER transducers in composite materials

The guided wave (GW) field excited by piezoelectric wafers and piezocomposite transducers in carbon-fiber composite materials is experimentally investigated with applications to structural health monitoring. This investigation supports the characterization of the composite long-range variable-length emitting radar (CLoVER) transducer introduced by the authors. A systematic approach is followed where composite configurations with different levels of anisotropy are analyzed. In particular, unidirectional, cross-ply [0/90]3S and quasi-isotropic [0/45/–45/90]2S IM7-based composite plates are employed. A combination of laser vibrometry and finite element analysis is used to determine the in-plane wave speed and peak-to-peak amplitude distribution in each substrate considered. The results illustrate the effect of the material anisotropy on GW propagation through the steering effect where the wavepackets do not generally travel along the direction in which they are launched. After characterizing the effect of substrate anisotropy on the GW field, the performance of the CLoVER transducer to detect damage in various composite configurations is explored. It is found that the directionality and geometry of the device is effective in detecting the presence and identifying the location of simulated defects in different composite layups.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85432/1/sms10_1_015014.pd

Guided Wave Experimentation Using CLoVER Transducer for Structural Health Monitoring

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76590/1/AIAA-2008-1970-977.pd

Guided wave excitation by a CLoVER transducer for structural health monitoring: theory and experiments

The guided wave (GW) field excited by a wedge-shaped, anisotropic piezocomposite transducer, surface-bonded on an isotropic substrate is investigated with applications to large area structural health monitoring. This investigation supports the development of the composite long-range variable-direction emitting radar (CLoVER) transducer. The analysis is based on the three-dimensional equations of elasticity, and the solution yields expressions for the field variables that are able to capture the multimodal nature of GWs. The assumption of uncoupled dynamics between the actuator and substrate is used, and their interaction is modeled through shear tractions along the transducer's radial edges. A similar problem is modeled using three-dimensional finite element simulations to assess the spatial and transient accuracy of the solution. Experimental tests are also conducted on pristine structures to validate the accuracy of the theoretical approach. The experimental studies employ CLoVER transducers developed in-house, and their manufacturing procedure is briefly described. Frequency response experiments based on piezoelectric sensors are conducted to assess the performance of the solution in the frequency domain. These tests are complemented by laser vibrometer measurements that allow the spatial and temporal evolution of the solution to be evaluated. The numerical simulations and experimental tests show that the wave time of arrival, radial attenuation, and azimuthal distribution are well captured by the theoretical solution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65106/2/sms9_7_075005.pd

Modeling of Wedge-Shaped Anisotropic Piezocomposite Transducer for Guided Wave-based Structural Health Monitoring

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77008/1/AIAA-2007-1723-966.pd

Minimal open sets on generalized topological space

We introduce the notion of minimal open sets in a generalized topological space (X μ). We investigate some of their fundamental properties and proved that any subset of a minimal open set on a GTS (X μ) is a μ-preopen se

Rapid, quantitative separation by high-performance liquid chromatography of methylated bases in transfer RNA

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22961/1/0000528.pd

Balance de la legislación de urgencia emitida en el marco de la emergencia sanitaria por la Covid 19 en el Perú y propuesta de reforma

La pandemia producida por el virus del SARS COV 2, es el episodio más importante a nivel mundial durante los últimos años por cuanto además de sus efectos sanitarios ha cambiado aspectos muy sensibles de la vida social y económica de las sociedades en todo el mundo. La necesidad de enfrentar los efectos de la enfermedad ha obligado a los Estados a recurrir a la emisión de normas de urgencia dictadas en el marco de prerrogativas excepcionales establecidas en la Constitución Política pero que no están diseñadas para enfrentar eventos de la magnitud y características de una emergencia sanitaria de proporciones mundiales. Por esa razón es necesario evaluar la pertinencia de dicha legislación en un contexto en donde la posibilidad de un nuevo episodio similar al vivido desde el 2020 no es un cálculo ajeno a la realidad, y en donde fenómenos como el calentamiento global, la contaminación y la sobre explotación de recursos naturales hacen pensar en la posibilidad de la presentación de emergencias sanitarias que con mayor recurrencia afecten a las sociedades. En esa línea de pensamiento, el siguiente artículo pretende aportar en ese análisis a partir de la descripción de las acciones que el Estado peruano implementó durante los años 2020 y 2021 para concluir en la necesidad de una reforma constitucional que permita al Poder Ejecutivo enfrentar eventos como los vividos en un marco de legalidad y respecto al equilibrio de poderes

Loss of MECP2 Leads to Activation of P53 and Neuronal Senescence.

To determine the role for mutations of MECP2 in Rett syndrome, we generated isogenic lines of human induced pluripotent stem cells, neural progenitor cells, and neurons from patient fibroblasts with and without MECP2 expression in an attempt to recapitulate disease phenotypes in vitro. Molecular profiling uncovered neuronal-specific gene expression changes, including induction of a senescence-associated secretory phenotype (SASP) program. Patient-derived neurons made without MECP2 showed signs of stress, including induction of P53, and senescence. The induction of P53 appeared to affect dendritic branching in Rett neurons, as P53 inhibition restored dendritic complexity. The induction of P53 targets was also detectable in analyses of human Rett patient brain, suggesting that this disease-in-a-dish model can provide relevant insights into the human disorder